Research Article
Design and Construction
S. M. Nassiri; S. Samsami; M. Loghavi
Abstract
Introduction Iran is a frontier of pomegranate fruit production in the world (with almost 40 % of the world`s production). However due to traditional processing operations is not ranked as the largest pomegranate exporter. Saveh, Neyriz and Ferdows are the top pomegranate producing cities in Iran. Pomegranate ...
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Introduction Iran is a frontier of pomegranate fruit production in the world (with almost 40 % of the world`s production). However due to traditional processing operations is not ranked as the largest pomegranate exporter. Saveh, Neyriz and Ferdows are the top pomegranate producing cities in Iran. Pomegranate is consumed as a fresh fruit as well as processed product as food additive, paste, syrup, jelly, pectin, jam, beverage, essence, vinegar and concentrate. Aril extraction is the first and essential postharvest operation for pomegranate processing. Arils are mostly extracted manually even in large scales for fresh and processed consumption. This labor intensive operation is rational when aril quality is an important index for consumer. But whenever pomegranate juice is desired, the aril quality has no priority for consumer, and therefore arils can be extracted with less care. Sarig (1985) was the first inventor of a pomegranate aril extractor who employed air jet force to extract the arils. Later, other researchers employed the same method as well as water jet to extract fruit juice and sac. In the present study, fabrication and evaluation of vibratory aril extractor augmented with air system was conducted. Materials and Methods The study was conducted using Rabab cultivar samples which were manually harvested from an orchard in Neyriz town, Fars province. Samples were kept in refrigerator at 5 0C till experimental trials. Initial moisture content of fruit skin, arils and internal fleshes were measured by gravimetric method as 31.7±2.6 %, 61.5±1.8 % and 42.8±1.4 %, respectively and for a whole fruit was measured 45.3±11.5 % (w.b.). For conducting laboratory tests, an aril extraction unit was designed and fabricated. It comprised a steel main frame, a 746 W electric motor, drive mechanism (eccentric and shaft), sample retentive unit, air jet unit, aril tank, and an air compressor-tank assembly. Sample retentive unit was designed in such a manner to hold a halved fruit. This unit was made from four elements, a hemisphere bowel, four pressure (spring) arms to apply force on skin of the sample, and four tension (spring) arms for fixing the sample in the bowel by applying pressure on the edges of the halved sample. Such configuration helped sample to open more and more while extracting the arils to expose trapped aril for easier extraction. Sample retentive assembly was vibrated by the electric motor and drive mechanism. Electric motor was equipped with an electric convertor to create different levels of vibration frequency. Also, the drive mechanism was designed in such a manner to create different levels of vibration amplitudes. According to the previous studies, 2 nozzles with 3.5 mm diameter were selected for air jet unit. Nozzles were spaced at 8 cm apart according to the measured mean diameter of samples. Outlet air jet from nozzles covered the cross sectional area of the halved fruit. Nozzles assembly was rotated 180 degrees clockwise and counterclockwise with an electronically controlled stepper motor. Pressurized air (from air tank) was transferred to nozzles assembly by flexible pipes. Air pressure was controlled at 500 kPa level by air regulator. To conduct experimental trials, samples halved at three different cutting directions (horizontal (equatorial), vertical and oblique) by a sharp cutter and halved samples were used for tests. Halved sample was fixed in bowel and then the unit was excited by the electric motor. The assembly was vibrated for 60 seconds before blowing the air jet for extra 30 seconds. Tests for air jet alone were conducted for 90 seconds and percentage of detached and damaged arils were calculated. Damaged aril during cutting process was subtracted from total damaged arils for each trial. Collected data were analyzed according to factorial experiments based on completely randomized design, and means were compared by Duncan post-hoc test. Data of combined and air jet alone systems were analyzed by two independent sample t tests. Results and Discussion ANOVA results revealed that cutting type, frequency and amplitude, significantly influenced the percentage of aril extraction at 5 % level of significance. The highest amount of extraction was obtained at 30 Hz frequency and 4 mm amplitude for diagonal cutting by 87 %. At this condition, 13.9 % of arils were damaged by air jet pressure. A significant difference in percentage of extracted and damaged arils was observed between vibratory-air and air systems at 5 % level of significance. The highest amount of aril extraction as well as damage was observed for vibratory-air system with the means of 80.1 % and 9.9 %, respectively. Conclusion Maximum percentages of extraction and aril damage were achieved by applying the combined system with as compared to air jet system alone, so that combined system increased aril extraction by 7.1 % with 2.2 % extra damages.
Research Article
Design and Construction
H. Rahmati Aidinlou; A. M. Nikbakht
Abstract
Introduction Increasing the area of absorber plate between the flowed air through the duct can be accomplished by corrugating the absorber plate or by using the artificial roughness underside of the absorber plate as the commercial methods for enhancing the thermohydraulic performance of the flat plate ...
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Introduction Increasing the area of absorber plate between the flowed air through the duct can be accomplished by corrugating the absorber plate or by using the artificial roughness underside of the absorber plate as the commercial methods for enhancing the thermohydraulic performance of the flat plate solar air heaters. Evaluation of this requires the construction of separated solar air heater which is costly and time consuming. The constructed solar flat-plate collector simulator can be a sufficient solution for obtaining the heat transfer and thermodynamic parameters for evaluating the absorber plate. The inclined broken roughness was chosen as the optimum roughness which is surrounded by three aluminum smooth walls. Materials and Methods The duct for both smooth and roughened plate have been constructed based on the ASHRAE 93-2010 standard. In order to achieve a fully thermal and hydraulic developed flow, the plenum is constructed. The centrifugal fan is considered by applying the required air volume at the pressure drop obtained by the duct, plenum and the orifice meter. The TSI velocity-meter 8355 is used to measure the velocity of air crossing through the pipe connected to the centrifugal fan. The micro manometer Kimo CPE310-s with the resolution of 0.1 Pa is used to measure the pressure drop across the test section of the smooth and roughened duct. The LM35 sensors are used to measure the absorber plate and air temperature through the test section. Obtained parameters are used to calculate the Nusselt number and friction factor across the test section for smooth and roughened absorber plate. The Nusselt number and friction factor parameters which is obtained for smooth absorber plate based on experimental set-up, is compared with Dittus-Bolter and Blasius equations, respectively, for validating the simulator. By calculating the Nusselt number and friction factor, Stanton number is obtained based on the equation (6), and thermohydraulic coefficient is calculated by the equation (5) for the desired roughness. Results and Discussion Pressure drop for smooth duct is obtained to be 20 Pa. Maximum velocity crossed through the plenum is calculated by the equation (8). Thereafter, pressure drop for plenum by considering the maximum velocity in equation (7), is obtained to be 1.16 Pa. The same procedure for maximum velocity which is crossed through the orifice meter is obtained by the equation (10) and then the pressure drop for orifice meter is calculated equal to 243 Pa by considering the velocity in equation (9). Total pressure is given by the equation (11) to be 246.16 Pa. The required power for centrifugal fan is obtained equal to 105 W from equations (12), (13) and (14), respectively. Both aforementioned Nusselt number variations with Reynolds number were monotonously increased by increasing the Reynolds number. The gained RMSE and coefficient of determination between the Nusselt numbers are 0.0566 and 0.6944, respectively. The obtained RMSE and coefficient of determination between the friction factors are 0.0004 and 0.6814, respectively. The low value of the RSME and high value of the R2 analysis for both Nusselt number and friction factor shows that there is a good agreement between the experimental data and empirical correlations. Fig. 8 demonstrates that the thermohydraulic coefficient is decreasing as the Reynolds number increased. The effect of friction factor related to the Stanton number is shown up more effective by increasing the Reynolds number. It should be noted that the same procedure is conducted for Han's experiment where the thermohydraulic performance is decreased as the Reynolds number increased. The maximum magnitude of the thermohydraulic performance was achieved at minimum 3149 Reynolds number. Conclusion The flat-plate solar collector simulator was designed based on the ASHRAE 93-2010 standard which consists of the centrifugal fan, chosen based on the required air volume by considering the pressure drop in the duct, plenum and orifice meter. The experiment was conducted between 3149 to 19247 Reynolds numbers. The good agreement between the comparison of the Nusselt number and friction factor obtained by the experiment for smooth duct was achieved by the Dittus-Bolter and Blasius equations, respectively, to validate the simulator. The obtained thermohydraulic coefficient for optimized roughness surrounded by three smooth walls was lower than the former investigated roughnesses at each Reynolds number
Research Article
H. Gholami; D. Kalantari; M. Rajabi Vandechali
Abstract
Introduction Recently, employment of rotary tillers has been expanded in gardens and small farms, especially in the northern of Iran. However using the L-shaped blades in the conventional rotary tillers have some problems such as severe vibration problems, weeds stucking around the blades, forming the ...
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Introduction Recently, employment of rotary tillers has been expanded in gardens and small farms, especially in the northern of Iran. However using the L-shaped blades in the conventional rotary tillers have some problems such as severe vibration problems, weeds stucking around the blades, forming the plow pan and lower performance due to the less powers of such small rototillers. Therefore in order to overcome the above mentioned problems, a rototiller with new ridged blades was designed, fabricated and tested in this research. Materials and Methods Experiments were carried out in one of the citrus orchards in Mazandaran, Sari. The experimental design was split plots based on randomized complete block design with three replications. The soil moisture as main plot varied in two levels of 13.5-21.9 and 21.9-30.3 percent based on dry weight and the rotational speed of blades as subplots varied in three levels of 140-170, 170-200 and 200-230 rpm. The measured parameters consist of soil particle mean weight diameter, soil bulk density, soil crumbling percentage, specific fuel consumption and machine efficiency. The diameter of soil particles was measured using a set of standard sieves with diameter ranging from 0.5 to 8 mm. Then a laboratory shaker was used to sift the samples. Each sample was shaken in 30 sec. The fuel consumption during the experiments was determined by the filled fuel tank method. Analysis of variance (ANOVA) and mean comparisons and interaction between the parameters were performed using the SPSS 16 software. Results and Discussion The results indicated that the soil particle mean weight diameter reduced by increasing blades rotational speed in both examined soil moisture contents. Results indicated that the soil crumbling percent increases with increasing the rotational speed. The main reason for this effect could be due to the more energy transferring to the soil at higher rotational speeds, which result in further crumbling of the soil slices. Regarding the results obtained in this study, the specific fuel consumption increased at first in a light slope, then in a steep rise with increasing the blades rotational speed. The reason can be the higher crumbling percent of the soil at higher rotational speeds and higher soil moisture contents (at the range of 21.9-30.3%), providing the more specific energy consumptions. The specific fuel consumption was the maximum at higher soil moisture content of 30 %. The results indicated that the blades rotational speed and soil moisture content had no significant effect on the field efficiency of the examined rototiller. The field efficiency varied in the range of 92 to 97% in all of the experiments, i.e., rotational speed between 140 to 230 rpm and moisture content ranging from 13.5 to 30.3%. The reason for that was due to the roughly similar turning times, minor adjustments, changing operators and some other parameters influencing the field efficiency. Reduction of the rotational speed of the rototiller from high-to-moderate speeds leads to decrease the fuel consumption to 17 liter ha-1, which could be significant in wide scale of soil tillage operations. As a general result, reduction of the rotational speed had some considerable advantages such as reducing power requirements, reducing blade wearing and maintaining soil structure. Conclusion Influence of soil moisture and rotational speed of blades on the soil particle mean weight diameter, soil crumbling percentage and specific fuel consumption were significant (P<0.01) for fabricated rototiller with new ridged blades. Statistical analysis indicated that the soil crumbling percentage and specific fuel consumptions increased linearly with increasing the rotational speed of blades. The determination coefficients of the crumbling percentage and specific fuel consumption as a function of rotational speed were 0.996 and 0.860, respectively. Meanwhile, clod mean weight diameter decreased linearly by increasing the rotational speed with a determination coefficient of 0.990. For achieving fine soil aggregates, combining high rotational speed and higher soil moisture (20 to 30%) is suggested, while to obtain a coarse soil gradation, low rotational speed and low soil moisture are more suitable compositions. The use of high rotational speed is not recommended due to increasing fuel consumption and consequently the soil erosion and environmental issues.
Research Article
K. Andekaeizadeh; M. J. Sheikhdavoodi; M. E. Khorasani
Abstract
Introduction Main part of energy consumption in agricultural mechanization is tillage operations therefore optimization of energy consumption in tillage operation is very important. A management method for system to optimize in agriculture is Simple Additive Weighting (SAW) methodology that this method ...
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Introduction Main part of energy consumption in agricultural mechanization is tillage operations therefore optimization of energy consumption in tillage operation is very important. A management method for system to optimize in agriculture is Simple Additive Weighting (SAW) methodology that this method can operate according to criteria of the systems. This method states that, which system has better performance? (for example the system for agricultural tractors, type of implements, methods of tillage, planting and harvesting, and etc). Fuel consumption is the most important factor in terms of energy consumption in tractor because the fuel energy contributes to help tractor to work . Specific draught is important force that measured for investigation of energy consumption of tillage implements, it can show the amount of drawbar force that optimized (for work width 1 meter implements tillage) by using this method. The multiplication of the drawbar force in forward speed factor resulted drawbar power. The most common method is using of tractors drawbar power in mechanized agriculture. Important factor for assessment and determination performance of tractor is drawbar power. Several studies have been showed that about 20 to 55%of available drawbar power was wasting by implements tillage. Another important parameters that affect on traction efficiency pull’s machine is slip. A simple additive weighting two-step procedure involving basic weighted as follows: (1) scale the values of all attributes to make them comparable; (2) sum up the values of the all attributes for each alternative. Materials and Methods In this study, three implements tillage were studied including moldboard plow, disk plow and disk harrow and they called A, B and C, respectively. Three different forward speeds of 3, 4, 5, 6 km.h-1 for each implements were selected according to the type of work at various depths. In this study fuel consumption factor was measured by means of micro-oval flow meter, forward speed was measured by a Doppler radar, Slip was measured by Proxy Sensor, and drawbar force was measured by a three point auto hitch dynamometer. Depth tillage was maintained by depth-knob control system. tillage implements for comparison proper class was rated tables (1), (2) and (3) that includes low depth (12.4 cm moldboard plow, disk plow 12.3 cm and 12.4 cm disk harrow), middle depth (18 cm moldboard plow, disk plow 17.4 cm and 15.2 cm disk harrow) and the high depth (23.5 cm moldboard plow, disk plow 23.4 cm and 17.2 cm disk harrow). Results and Discussion The results of Table 5 shows a higher combined ratio of the amount of energy that is optimum performance in the form of (1), (2) and (3). Also Combined ratio is a way that the whole system will be valued according to their criteria that objective criteria according to the study, we classified as positive and negative criteria and all its problems the system had a higher combined ratio than the rest of the system is the optimal system performance. Kheiralla et al. (2004) in their research used statistical methods and indicated that energy efficiency disk harrow, disk plow and moldboard plow was better than the other devices but Simple Additive Weight way of energy efficiency in different conditions partially expressed. Conclusion The results showed that disk plow in different depth tillage and forward speed, has higher energy efficiency. Disk harrow compared with other tillage implements recommended for the high depth. Disc harrow is not optimal in the low depth because it compared to other implements has lower slip and tractive efficiency. Moldboard plow is optimum use energy in depth and average speeds (4 and 5 km h-1).
Research Article
H. Abedi; S. Firouzi; M. S. Allahyari
Abstract
Introduction Olive is one of the most valuable worldwide trees that produces useful products having high nutritional values. It is widely grown in many parts of world. The cost of olives hand picking is estimated to be about two-thirds of the total gross return of olive production. Therefore, various ...
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Introduction Olive is one of the most valuable worldwide trees that produces useful products having high nutritional values. It is widely grown in many parts of world. The cost of olives hand picking is estimated to be about two-thirds of the total gross return of olive production. Therefore, various types of olive harvesting machineries were developed in the world. Guilan Province of Iran is one of the leading regions for olives production in Iran. At the present time, almost all olives produced in Guilan province of Iran are manually harvested. Review of the reports showed that no research was performed to study the factors affecting the development of mechanized olive picking in Guilan Province, Iran. Due to the complexity of using the olive harvest machineries, identifying the factors affecting of their application is essential. Therefore, a Delphi study were conducted to identify and analysis the drivers and barriers for mechanized olive harvest in Guilan province, Iran. Materials and Methods This research was conducted using the Delphi technique in Guilan Province, Northern Iran. Delphi technique is a structured process to gather and classify the knowledge of a group of experts. Through consultation with professors and researchers in related institutions, 22 experts from the subsidiary offices of agricultural organization of Guilan Province were selected for the study. In the first round of the study, the participants were asked to answer to two open questions about the driving factors and barriers of mechanical olive harvest in Guilan Province. Nineteen items were found as driving factors and seventeen as barriers for developing the mechanical olive harvesting in Guilan Province. In the second phase of the study, the respondents were asked to answer to the all items written in the form of a five-level Likert scale, and finally, experts of panel were asked to answer to the top 10 items of driving factors and barriers in percent form. The results were analyzed using SPSS computer software and arranged in various tables. Results and Discussion Based on the findings of last phase of the Delphi study, ‘modification of olive groves and applying the technical fundamentals to the orchards’, agreed upon by 98.15% of the participants, was identified as the first driving priority to mechanize the olive harvest in Guilan Province. In this regard, pruning olive trees is the first modification practice which should be applied to the old olive groves of the region. Olive cultivar is the other parameter affecting on the performance of olive harvest machinery. Therefore, this parameter also must be considered in construction of new groves or renovate the old olive gardens. ‘Special support for related researches to construct and optimize the olive harvesting machinery’ was also as the second driving factor to develop mechanized olive harvesting in Guilan Province. In this regard, design and fabricate the new machinery based on the local conditions is a matter of great importance. The findings of last phase of the Delphi study also indicated that ‘the slope of most olive growing plots’, agreed upon by 95.62% of the respondents was identified as the first barrier for mechanical olive harvesting in Guilan Province. Thus, research on all the technical aspects of hand-held harvesting machines, including hand-held shakers should take priority. Lack or shortcoming of planning for the development of the olive harvest mechanization was also as the second barrier to develop mechanized olive harvesting in Guilan Province. Therefore, codifying a regional macro-plan to develop mechanized olive harvesting in Guilan Province must be considered among the important programs of Guilan’s Agricultural Organization, Iran. Conclusion The results of this study showed that many factors affect the mechanical harvesting of olives in Guilan province which modification of olive groves, special support for related researches to construct and optimize the olive harvesting machinery are among the most important driving factors. Therefore, to develop the mechanical olive harvester, developing the applied strategies to support the olive growers, modification of foreign machinery, and design and fabricate of new olives harvest machinery are essential in Guilan province, Iran.
Research Article
Image Processing
F. Behzadi Pour; M. Ghasemi-Nejad Raeini; M. A. Asoodar; A. Marzban; S. Abdanan Mehdizadeh
Abstract
Introduction Today, attention to safety and environmental issues in all sectors in agriculture, industry and services is very important. Chemical poisons play an important role in rapid progress of agricultural products. Every year about 25 to 35 percent of the world's crops are affected by insects, ...
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Introduction Today, attention to safety and environmental issues in all sectors in agriculture, industry and services is very important. Chemical poisons play an important role in rapid progress of agricultural products. Every year about 25 to 35 percent of the world's crops are affected by insects, weeds and plant pathogens disappear and this figure would be raised to 80% if no control was applied. Drift problem and its devastating effects are the most important issue which related to users and sprayers manufacturers. Spray drift reduction and improvements in the efficiency of pesticide application processes are global goals. Where ever spraying is applied, drift will be produced and it must be controlled by controlled of the droplet size. The application of these sprayers is the high in the farms (the number of 2303 in Iran). So, this research was carried out to improve the quality of work in these sprayers by studying the droplets diameter and the spray quality index. Materials and Methods The research was conducted at the University of Khouzestan Ramin Agriculture and Natural Resources. Tests were done with 20 m of water sensitive papers at a distance of 2 meters from each other. To evaluate the technical items affecting on drift, an experiment was conducted using a turbo liner sprayer (TURBINA S.A. 800) and the John Deer (JD) 3140 tractor. A completely randomized factorial design was applied. By using 3 replications and the factors were spraying pressure applying three levels (10, 25 and 35 bar), the fan speed with two levels (1998 and 2430 rpm) and forward speed with two levels (9 and 13.5 km hr-1). The sprayer started the application, spraying a solution of water and tracer (yellow Tartrazine E 102), 15m before the water sensitive papers and then moved over the water sensitive papers. The spraying was continued 15 m after the end of the sampling area. After spraying, sensitive papers were photographed and then volume diameter of 50% (DV50) and median numerical diameter (NMD) and spraying quality indicator were calculated. A Spectrophotometry device at the wavelength of 427 nm, Image J and sas 9.2 software were used for measurement. This research was carried out in accordance with the calendar crop canola spraying in field conditions and the weather was calm that the wind speed was 0- 2.5 km hr-1, relative humidity was 29.7% - 32.5% and air temperature was 18.8˚C – 20.7˚C. Results and Discussion According to the results sprayer pressure, fan speed and forward speed were shown significantly different (P≤0.01) on the volume diameter of 50% (DV50) and median numerical diameter (NMD). The effect of spraying pressure on distributing quality indicator was shown significant (P ≤ 0.01), but the fan and forward speed did not shown any significant effect. Mean comparison of the interaction of pressure and forward speed on the spray quality index and the number median diameter were shown significant (P ≤ 0.01), but they did not shown any significant effect on the volume diameter of 50% (DV50). With increasing spraying pressure and fan speed, the droplet size, volume diameter of 50% (DV50) at 72% and numerical median diameter (NMD) at 69% and distributing quality indicator at 46% were decreased that were corresponded with the result of Czaczyk et al. (2012), Peyman et al. (2011), Nuyttens et al. (2009) and Landers and Farooq (2004). With increasing spraying pressure and forward speed, the droplet size, numerical median diameter (NMD) at 63% and distributing quality indicator at 35% were decreased that these resulted were corresponded with the results of Naseri et al. (2007) and Dorr et al. (2013). Conclusion With increasing spraying pressure, fan and forward speed, the droplet size, volume diameter of 50% (DV50) and numerical median diameter (NMD) were decreased. Therefore, spraying quality indicator was decreased. The maximum pressure (35 bars), maximum fan speed (2430 rpm) and maximum forward speed (13.5 km hr-1) were able to produce the minimum spraying quality indicator (10.3). At the minimum pressure (10 bars), maximum fan speed (2430 rpm) and minimum forward speed (9 km hr-1), the maximum spraying quality indicator (2.91) was resulted.
Research Article
A. Bakhshipour Ziaratgahi; A. A. Jafari; Y. Emam; S. M. Nassiri; S. Kamgar; D. Zare
Abstract
Introduction Sugar beet (Beta vulgaris L.) as the second most important world’s sugar source after sugarcane is one of the major industrial crops. The presence of weeds in sugar beet fields, especially at early growth stages, results in a substantial decrease in the crop yield. It is very important ...
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Introduction Sugar beet (Beta vulgaris L.) as the second most important world’s sugar source after sugarcane is one of the major industrial crops. The presence of weeds in sugar beet fields, especially at early growth stages, results in a substantial decrease in the crop yield. It is very important to efficiently eliminate weeds at early growing stages. The first step of precision weed control is accurate detection of weeds location in the field. This operation can be performed by machine vision techniques. Hough transform is one of the shape feature extraction methods for object tracking in image processing which is basically used to identify lines or other geometrical shapes in an image. Generalized Hough transform (GHT) is a modified version of the Hough transform used not only for geometrical forms, but also for detecting any arbitrary shape. This method is based on a pattern matching principle that uses a set of vectors of feature points (usually object edge points) to a reference point to construct a pattern. By comparing this pattern with a set pattern, the desired shape is detected. The aim of this study was to identify the sugar beet plant from some common weeds in a field using the GHT. Materials and Methods Images required for this study were taken at the four-leaf stage of sugar beet as the beginning of the critical period of weed control. A shelter was used to avoid direct sunlight and prevent leaf shadows on each other. The obtained images were then introduced to the Image Processing Toolbox of MATLAB programming software for further processing. Green and Red color components were extracted from primary RGB images. In the first step, binary images were obtained by applying the optimal threshold on the G-R images. A comprehensive study of several sugar beet images revealed that there is a unique feature in sugar beet leaves which makes them differentiable from the weeds. The feature observed in all sugar beet plants at the four-leaf stage was a stretched S-shaped curve at the junction of the leaf and petiole. This unique shape characteristic was used as the pattern for sugar beet detection using GHT. To implement the Hough transform in the images, a 50-member group of samples was prepared from S-shaped curve to build appropriate patterns. Desired features for the Hough transformation were extracted from the patterns. In the next step, the attempts were made to find the images for the shapes similar to each of the patterns. Results and Discussion Plants were thoroughly separated from soil and residues. The accuracy of segmentation algorithm was achieved by almost 100%. The accuracy of the generalized Hough algorithm was evaluated in two stages. In the first stage, the algorithm accuracy was assessed in detecting patterns in the images. Results showed that the accuracy of the algorithm was 96.21%. In the second stage, the algorithm was evaluated for some other test images, whereas the algorithm achieved an overall accuracy of 91.65%. In some cases, the presence of a large overlap between objects in the image reduced the detection accuracy. This was because of two main reasons; 1) high interference and ambiguity in the object edges, so that Hough transform was not able to detect the predefined patterns in the objects and, 2) weeds highly overlapped with sugar beet plants and thereby they were wrongly detected as sugar beet. However, since there is no or little interference between plants at the four-leaf stage, this interference can be eliminated by morphological operations. Due to this fact, it can be said that the results of GHT algorithm are acceptable for the detection of sugar beet in the plants close to four-leaf stage. Conclusion A special feature in the shape of sugar beet leaves was used as a criterion to distinguish between sugar beet and weeds. The results showed that by quantifying this special feature, which is an S-shaped curve near the petioles connection of beet leaves, sugar beet can be discriminated from weeds with an accuracy of 91.65 %. Recalled that this feature is a shape characteristic, therefore, the generalized Hough algorithm must be applied prior to plant canopy development, which is consistent with the critical period of weed control in sugar beet fields.
Research Article
F. Mahdiyeh Broujeni; A. Maleki
Abstract
Introduction Nowadays, many studies were performed about noise source and its type and effects related to duration of sound emission. Most of these researches just report sound pressure level in frequency or time domain. These researches should be continued in order to find better absorber material in ...
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Introduction Nowadays, many studies were performed about noise source and its type and effects related to duration of sound emission. Most of these researches just report sound pressure level in frequency or time domain. These researches should be continued in order to find better absorber material in noise pollution. Use of fractal geometry is a new method in this filed. Wave fractal dimension value is a strong tool for diagnosis of signal instability and fractal analysis is a good method to finding sound signal characteristics. Therefore the aim of this study is on the fractal geometry of SAMPO 3065 combine harvester signals and determine the fractal dimension value of these signals in different operational conditions by Katz, Sevcik, Higuchi and MRBC methods. Materials and Methods In this research, sound signals of SAMPO 3065 harvester combine that were recorded by Maleki and Lashgari (2014), were analyzed. Engine speed (high and low), gear ratio (neutral, 1st, 2nd, 3rd gear), type of operation (traveling and harvesting) and microphone position (in and out of the cabin) were the main factors of this research. For determining signal fractal dimension value in time domain, wave shape supposed as a geometrical shape and for calculation of fractal dimension value of these signals, total area of wave shape was divided into boxes in 50, 100, 200 milliseconds with an interval 25 millisecond box. Then Fractal dimension value of these boxes was calculated by Katz, Sevcik, Higuchi and MRBC methods using MATLAB (2010a) software. SPSS (Ver.20) software was used for further analysis. Results and Discussion Results showed mean effects of engine speed, microphone position, gear ratio, type of operation, box length, calculation method and all of two way interaction effects were significant. Means of Fractal Dimension in the road and field position were 1.4 and 1.28 respectively. The Maximum growth ratio of fractal dimension value during engine speed levels was related to road position. By increasing of box length and number of data points in each box, the fractal dimension value was increased. Investigation of fractal dimension methods showed changes of box length did not affect fractal dimension value in Higuchi method and range of this factor while box length varied were 0.001, 0.171, 0.005 and 0.024 in Higuchi, Katz, MRBC and Sevcik method respectively. These results showed that Katz method has maximum sensitivity and MRBC method like Higuchi method had the minimum sensitivity by changing of box length. In this research fractal dimension value of SAMPO Combine signals in the time domain in different operation conditions were investigated by Katz, Sevcik, Higuchi and MRBC methods. These values varied from 1 to 1.5 in different conditions. Maximum fractal dimension value was 1.63 in case of no cabin by MRBC method. Increasing of box length or further the data point cause of increasing fractal dimension value with increasing of sound pressure level of combine due to increasing of engine speed and working of different parts of harvesting combine. Due to define of sound pressure level, and increasing of this item in each gear ratio ,this can be justify that in high engine speed, wave turbulent is higher than low speed and this turbulent appeared in fractal dimension value. Conclusion One of the important factors in the evaluation of the time series disturbance is fractal dimension. Therefore, the study of sound signals can be an effective role in this regard. Factors such as the cabin existence, gear type, engine speed and operational state of combining parts had a considerable role in distribution of combinimg sound signals and fractal dimention of these signals. For example cabin acts as a barrier in the sound wave and decrease the sound pressure level near driver ear and cause decrease fractal dimention of signals. The study of time series with different lengths have shown that the duration time of the calculation in various methods had a significant effect. Increasing the length of signals due to a higher number of signal data cause to increase calculation time of fractal dimension calculation, while the changes of fractal dimension in increasing of the number of data is minimum and negligible. Therefore, the choice of the appropriate length of the signal is important.
Research Article
R. Rostami Baroji; S. S. Seiiedlou Heris; J. Dehghannya
Abstract
Introduction Drying foods, fruits and vegetables is a suitable method to reduce post-harvest losses of the crops. Drying is considered as a simultaneous heat and mass transfer process. Various physical, chemical and nutritional changes occur during drying of foods and are affected by a number of internal ...
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Introduction Drying foods, fruits and vegetables is a suitable method to reduce post-harvest losses of the crops. Drying is considered as a simultaneous heat and mass transfer process. Various physical, chemical and nutritional changes occur during drying of foods and are affected by a number of internal and external heat and mass transfer parameters. External parameters may include temperature, velocity and relative humidity of the drying medium (air), while internal parameters may include density, permeability, porosity, sorption–desorption characteristics and thermo physical properties of the material being dried. In this regard, understanding the heat and mass transfer in the product will help to improve drying process parameters and hence the quality. The mathematical model that reflects the drying process physics is a complex model. Particularly because of the process of convection drying of materials with high initial water content, boundary conditions should be assumed in the model describing heat and mass transfer. Ruiz-López and García-Alvarado (2007) proposed a model that provides a simple mathematical description for food drying kinetics and considered both shrinkage and a moisture dependent diffusivity. Food temperature was considered constant. The objectives of this work are: (a) to develop a mathematical model for simulating simultaneous moisture transport and heat transfer of pretreated carrot sample; (b) to study numerically the effect of the air drying conditions and pretreated on the drying of carrot and (c) to calculate the density and effective diffusion coefficients of carrot under various conditions. Materials and Methods In order to compare experimental and numerical analysis results, a laboratory scale convection dryer was used for experimental work. Cylindrical samples before entering the dryer were pretreated with ultrasound at frequency of 28 kHz for 10 min and microwave at 1 W g-1 power for 15 min. Experimental results of moisture evolution and volume changes during drying were used to estimate moisture diffusivity and product density. Transient three-dimensional simulation of heat and mass transfer was performed with a set of initial and boundary conditions using the finite element method. The effect of the aforementioned pretreatments was applied in terms of the modified effective moisture diffusion coefficient in the heat and mass transfer equations. Results and Discussion The effect of the ultrasonic pretreatment on drying was mainly observed during the air-drying stage where a significant increase in water effective diffusivity was found. Ultrasonic waves can cause a rapid series of alternative compressions and expansions, in a similar way to a sponge when it is squeezed and released repeatedly (sponge effect). Microwave pretreatment reduced the initial moisture content and slightly increased the coefficient. The values of moisture diffusivity found in this study was in the order of - m2 s-1 which is typical value for drying of agricultural product (Zielinska and Markowski, 2010). Comparison of the experimental and predicted moisture and temperature profiles showed that the model could predict the heat and mass transfer phenomena with good accuracy. In this section, some simulation results are presented. The simulated moisture contents in the center and on the surface during drying showed that moisture content on the surface decreases rapidly for a short time due to the evaporation during precooling. Then it starts to increase because of the moisture diffusion from the layers under the surface towards. The temperature inside the object increases with an increase in the drying time since the temperature of the drying air is higher than that of the object. As a result of these transient and non-uniform temperature distributions, the moisture diffusivity which depends on the moisture will vary and in turn the rate of the moisture diffusion inside the object. As seen in the figure, the distributions appear not to be symmetrical. Higher temperature and moisture gradients are obtained at the side wall due to the upstream of the drying air. Conclusion A theoretical analysis of pretreated and non-pretreated carrot drying process was presented. The main innovation introduced by this study was represented by the model formulation. This, in fact, simulated the simultaneous three dimensional heat and moisture transfer accounting for the variation of both air and food physical properties as functions of local values of temperature and moisture content. Moisture diffusivities of pretreated and non-pretreated carrot have been determined experimentally and moisture diffusivities of pretreated and non-pretreated carrot were found to increase with using of ultrasound pretreated. The effect of the aforementioned pretreatments was applied in terms of the modified effective moisture diffusion coefficient in the heat and mass transfer equations. Comparison of the experimental and predicted moisture and temperature profiles showed that the model could predict the heat and mass transfer phenomena with good accuracy. The model can be used as a proper tool in the design optimization and the optimal determination of the dryer performance parameters.
Research Article
J. Habibi Asl; L. Behbahani; A. Azizi
Abstract
Introduction Many vegetables such as mint are highly seasonal in nature. They are available in plenty at a particular period of time in specific regions that many times result in market glut. Due to perishable nature, huge quantity of vegetables is spoiled within a short period. The post-harvest loss ...
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Introduction Many vegetables such as mint are highly seasonal in nature. They are available in plenty at a particular period of time in specific regions that many times result in market glut. Due to perishable nature, huge quantity of vegetables is spoiled within a short period. The post-harvest loss in vegetables has been estimated to be about 30-40% due to inadequate post-harvest handling, lack of infrastructure, processing, marketing and storage facilities. Therefore, the food processing sector can play a vital role in reducing the post-harvest losses and value addition of vegetables which will ensure better remuneration to the growers. Drying is a common technique for preservation of food and other products; including fruits and vegetables. The major advantage of drying food products is the reduction of moisture content to a safe level that allows extending the shelf life of dried products. The removal of water from foods provides microbiological stability and reduces deteriorate chemical reactions. Also, the process allows a substantial reduction in terms of mass, volume, packaging requirement, storage and transportation costs with more convenience. Sun drying is a well known traditional method of drying agricultural products immediately after harvest. However, it is plagued with in-built problems, since the product is unprotected from rain, storm, windborne dirt, dust, and infestation by insects, rodents, and other animals. It may result in physical and structural changes in the product such as shrinkage, case hardening, loss of volatiles and nutrient components and lower water reabsorption during rehydration. Therefore, the quality of sun dried product is degraded and sometimes become not suitable for human consumption. For these reasons, to utilize renewable energy sources, reduce vegetable losses and increase farmers income, the current project has been conducted in the Agricultural Engineering Department of Khuzestan Agricultural Research Center during the years 2011-2013. Materials and Methods In this research an indirect cabinet solar dryer with three trays and grooved collector was constructed. To improve air convection, a chimney was mounted above the dryer. The dryer performance was evaluated by drying mint leaves in three levels of mass density of 2, 3, and 4 kg m-2 at two drying manners of natural and forced convection and compared with drying mint leaves in shade as the traditional method. Results and Discussion The results showed that total drying time required in different solar drier treatments was 3.5 to 15 h, while it was about 5 days in traditional method. Drying time in upper trays was more as the air flow decreased due to increase in mass density. Mean required drying time in forced convection was 29.7% less than that of natural convection. Maximum essences with 0.80% and 0.76% were belonged to "natural convection and 3kg m-2 mass density" and "forced convection and 4 kg m-2 mass density" treatments respectively, while minimum one with 0.30% was for "forced convection and 2 kg m-2 mass density" treatment. Also, the highest and lowest chlorophyll content with 8.51 and 4.18 mg ml-1 were measured in "natural convection and 3 kg m-2 mass density" and "forced convection and 4 kg m-2 mass density" treatments respectively. According to obtained results, 3 and 4 kg m-2 mass density can be suggested for natural and forced convection solar drying of mint leaves in Khuzestan condition respectively. Conclusion In order to reduce vegetable losses and increase Khuzestan vegetable producers income, indirect cabinet solar dryer for drying mint leaves in winter season, could be an appropriate option. For natural and forced convection drying methods, mass density of 3 and 4 kg m-2 is recommended respectively.
Research Article
F. Khoshnam; S. R. Hassan Beigi Bidgoli; M. Namjoo; M. Doroozi
Abstract
Introduction Cucumis melo includes a wide range of varieties. The acoustic is production, transmission and energy received form medium vibrations. Acoustic or sonic tests applies for grading productions, ripening determination of fruit firmness and sorting of broken eggs and so on in agriculture. Currently ...
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Introduction Cucumis melo includes a wide range of varieties. The acoustic is production, transmission and energy received form medium vibrations. Acoustic or sonic tests applies for grading productions, ripening determination of fruit firmness and sorting of broken eggs and so on in agriculture. Currently these methods are generalized for measuring non-spherical fruits properties. The primary objective of the present research was to investigate the effect of acoustic system variables such as impact places, impactor material type, pendulum angle and sound level meter position on acoustics response of two different melon varieties, including Zard-Eyvanekey and Sousky-Sabz. These results can be useful for designing acoustic implements related to agricultural products. Materials and Methods This research was conducted on 65 samples of Zard-Eyvanekey and Sousky-Sabz varieties (export varieties). A laboratory recording system used to acquire the acoustic impulse information that was comprised a mechanical excitement mechanism (an impactor such as pendulum), sound level meter, a lap-top computer and software to control the experimental setup and to analyze its results (Cool Edit Pro 2.0 Software), and melon-bed. The impactor consists of diameter and long copper rod 3 mm and 256 mm, respectively. The ball mass was 72.13 gram. The acoustic signal was sensed by a sound level meter (SLM) type 2270 B&K company Denmark. The samples locate on soft cushion for keeping because this bed prevents vibration distortion and causes free vibration. We consider three measurements on equator or mid-section of each fruit (approximately 120 degree) for diminishing inherent diversity of sample shapes. The sound level meter was placed at a distance of 2-5 mm from the fruit surface. The effects of sound level meter, impactor ball and pendulum angle on sound signals were investigated. The effects of other parameters were analyzed by factorial test in randomized complete plot by three replications for each sample. The treatments were 36 and 65 melons of each variety were selected. Results and Discussion The average samples peaks were 10576 and 28663 at 90 and 180 degrees respect to impact place, respectively. Other factors such as impactor ball type (steel), impact angle (70 degrees) and variety type (Zard-Eyvanekey) were constant. The resonance frequency was 123.05 Hz for both SLM position. The averages of peak sound pressure level were 55.29 and 52.38 dB at 90 and 180 degrees positions, respectively. It concluded that the change of sound pressure meter (SLM) position of 90 to 180 degree caused to increase sound pressure level but had no effect on reach the time to peak and resonance frequency. The effect of impactor ball material and impact angle of pendulum on recording signals approximately resemble up and did not state here. The factor levels were sound level meter position respect to impact place (two levels), impactor ball material (three levels) and impact angle of pendulum (three levels). We found that effect of sound level meter position; ball material and impact angle variables on sound pressure level values and interaction effect of sound level meter impact angle on FFT magnitude was significant at 1% level in both varieties. None of the variables and interactions has effect on the resonance frequency in both varieties. It can be concluded from tables that resonance frequency was more suitable than sound pressure level and FFT magnitude in acoustic tests. The increment of angle caused to increase impact velocity because the length and mass of pendulum rod were constant. We can state the above conclusion about impact velocity (excitement velocity) too, e.g. the impact velocity (excitement velocity) had no effect on resonance frequency while it effected on sound pressure level and FFT magnitude. This conclusion coincides to others researchers. Conclusion The impactor ball, pendulum angle, sound level meter position and variety type factors did not showve significant effect on resonance frequency but they had significant effect on FFT magnitude and sound pressure meter. Because of the high pressure level and measurement easily, it was recommended the position 90 degrees of microphone respect to impact place for acoustics measurements. The maximum sound pressure levels were 54.43, 54.81 and 55.11dB for glass, steel and plastic, respectively. Other factors such as SLM position (180 degrees respect to impact), impact angle (70 degrees) and variety type (Zard-Eyvanekey) were constant. Because of receiving high pressure level from impact angle of 70 degrees respect to 20 and 45 degrees, it was recommended for acoustics measurements. It can be used the lower angles by considering the low background sound.
Research Article
B. Jamshidi; A. Arefi; S. Minaei
Abstract
Introduction In recent years, the determination of firmness as an important quality attribute of apple fruits has been widely noticed. Common methods for firmness measurement are destructive and cannot be applied in sorting lines. Therefore, development of a non-destructive, simple, fast, and the low-cost ...
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Introduction In recent years, the determination of firmness as an important quality attribute of apple fruits has been widely noticed. Common methods for firmness measurement are destructive and cannot be applied in sorting lines. Therefore, development of a non-destructive, simple, fast, and the low-cost determination technique of firmness is imperative. Dynamic speckle patterns (DSP) or bio speckle imaging as a new optical technique has been recently noticed for non-destructive quality assessment of food and agricultural products. In this research, the feasibility of using this technique was investigated for non-destructive prediction of firmness in intact apples during five months of cold storage. Materials and Methods During the harvest season, in 2013, a total of 540 ‘Red Delicious’ apples were obtained from a local orchard in Oshnaviyeh, Iran. The apples with similar color and shape were collected from several trees in the same place. The samples were stored under cold conditions for five months. Five experiments were carried out; the first experiment was done immediately after harvesting and other tests were performed during storage time, i.e. 30, 60, 120, and 150 days after harvesting date. In each experiment, the samples were illuminated by two laser diodes at the wavelengths of 680 nm and 780 nm, separately. DSP images of each fruit were acquired using a CCD camera. Then, time history of the speckle pattern (THSP) was created for each sample. After taking images, reference measurements were carried out for each sample to determine its firmness. Quantification of DSP activity was done using the statistical features of inertia moment (IM) and the absolute value of differences (AVD) extracted from the THSP images. Moreover, features of the images were extracted based on texture and wavelet transform. Finally, artificial neural network (ANN) models were developed for prediction of apple firmness based on image’s information obtained from the wavelengths of 680 nm and 780 nm, and the reference measurements. The 60, 15, and 25 percent of total samples were randomly used for calibration, cross-validation, and test validation sets, respectively. The correlation coefficient between measured and predicted values of the firmness and also the standard error of prediction (SEP) were calculated to compare the performance of the different ANN models. Results and Discussion After one month of the storage, apples lost about 15 percent of their initial firmness.The softening process continued and the firmness index dropped to 48.05 N (a total decrease of 42%). A significant difference was observed among the mean values of the firmness belong to the different storage times. In first and second months of the storage, a negative linear relationship was observed between DSP activity and the firmness. The lowest value of IM was observed for apples belonged to the harvesting date. DSP activity suddenly increased after 30 days of the storage. This ascending trend continued and reached to its maximum value on the 60th days of the storage. It was noted that DSP activity is significantly affected by the chlorophyll absorption during this period. Moreover, DSP activity at the wavelength of 680 nm was more than that at 780 nm. After two months of the storage, a significant decrease in DSP activity was observed for both wavelengths of 680 nm and 780 nm. The main reason for this phenomenon came back to changes in carbohydrates. During this ripping period, starch, which plays a main role in backscattering phenomenon is converted into simpler carbohydrates and it causes an increase in soluble solid contents and a decrease in the number of scattering centers. After developing the ANN models, the correlation coefficient of the prediction (rp) for different topologies was ranged from 0.74-0.81 and 0.81-0.83 for the wavelengths of 680 nm and 780 nm, respectively. Moreover, standard error of prediction (SEP) was between 8.4-9 N and 8.1-8.7 N for the wavelengths of 680 nm and 780 nm, respectively. The achieved results may be more attractive when they are compared with obtained results using multispectral/hyperspectral scattering imaging, as expensive and rather complicate techniques for non-destructive firmness assessment in apple fruits. Conclusion It was concluded that dynamic speckle patterns (DSP) or bio speckle imaging could be a simple, low-cost and appropriate technique for non-destructive prediction of firmness in intact apples during storage.
Research Article
M. Torkian Boldaji; A. M. Borghaee; B. Beheshti; S. E. Hosseini
Abstract
Introduction Thermal processing has a huge impact on the textural attribute of the final food product and texture is a major factor contributing the overall quality of food. Ohmic heating is an advanced thermal processing method in which heat is internally generated within foods by passing an alternating ...
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Introduction Thermal processing has a huge impact on the textural attribute of the final food product and texture is a major factor contributing the overall quality of food. Ohmic heating is an advanced thermal processing method in which heat is internally generated within foods by passing an alternating electric current through them. Ohmic heating can volumetrically heat the entire mass of a food system, resulting in faster heating, better quality and less energy consumption than conventional thermal processing. Gradient voltage and electrode type have high effect on ohmic heating system. Materials and Methods In this study, the effect of voltage gradient and electrode type on moisture reduction time, a/b, ΔE color indexes and energy consumption were studied. For this purpose, four levels of voltage gradients (5, 7, 9 and 11 V cm-1) and four electrode types (Aluminum, Stainless steel, Brass and Graphite) was investigated by ohmic heating in tomato paste processing. Tomato used in this study was purchased from a local market. The whole tomatoes were washed, crushed and mixed in a way that a red less-viscous liquid obtained (Fig. 1). This liquid was considered as tomato samples in the remainder of the article. Ohmic cooking experiments were conducted in laboratory scale ohmic heating system consists of a power supply, a variable transformer, power analyzer, a microcomputer, digital scale (GF-6000) and thermometer (Dual inpur RTD 804U) (Fig. 3). The ohmic cell had a PTF cylinder with an inner diameter of 0.05 m, a length of 0.10 m and two electrodes on both side of the cell. A hole with 3 mm diameter to insert the thermocouple was created and two holes with 5 mm diameter was created on surface of cell. One of them was used for pouring tomato puree and other for exiting steam from cell. Temperature uniformity was checked during previous heating experiments by measuring the temperatures at different locations in the test cell. Ohmic heating was accomplished till the moisture content of the tomato samples reduced from initial moisture content of as 91(wet basis) to a safer level of 70 (wet basis). Moisture reduction time, a/b and ΔE color indexes, temperature and energy consumption were measured. Results and Discussion The results of the nonlinear mathematical model showed that the effect of different voltage gradient levels on moisture reduction time, ΔE parameters and energy consumption had a good agreement (α≤0.01) as well as voltage gradient had a significant effect on a/b color index (α≤0.05). Electrode type had significant effect on processing time, ΔE (α≤0.01), on energy consumption and a/b index (α≤0.05). Interaction of voltage gradient and electrode type was significant on processing time, energy consumption, a/b and ΔE (α≤0.05). In all electrodes by increasing the voltage gradient, processing time and energy consumption were reduced. For example by increasing the voltage gradient from 5 to 11 V cm-1, processing time and energy consumption were decreased on average 38% and 23%, respectively. Minimal processing time and minimal energy consumption were observed in 11 V cm-1 with graphite electrode that were 17 min and 203 kJ, respectively. As well as maximum processing time and maximum energy consumption were obtained in 5V cm-1 with aluminum electrode that were 105.21 min and 321 kJ, respectively. But maximum a/b parameter and minimal ΔE index were observed with stainless steel electrode in 11V cm-1. In determining the best electrode, in addition to the processing time and energy consumption, product quality is also an important parameter. However, graphite electrode has better performance in terms of time and energy consumption, but stainless steel electrode has better performance in term of product quality. Since the production of food, quality is an important parameter, and also the two electrodes graphite and steel are similar in terms of energy consumption and processing time, but stainless steel electrode is better in term of quality, so stainless steel electrode is selected for ohmic heating tomato paste. Conclusion Different voltage gradients and Electrode type have a significant effect on processing time, energy consumption, ΔE and a/b color indexes. Minimal processing time and minimal energy consumption were observed in 11 V cm-1 with graphite electrode that were 17 min and 203 kJ, respectively. But maximum a/b parameter and minimal ΔE index were observed with stainless steel electrode in 11V cm-1. Stainless steel electrode and 11 V cm-1 voltage gradient were the best condition for tomato paste processing by ohmic heating.
Research Article
A. Safrangian; L. Naderloo; H. Javadikia; M. Mostafaei; S. S. Mohtasebi
Abstract
Introduction Vibrations include a wide range of engineering sciences and discuss from different aspects. One of the aspects is related to various types of engines vibrations, which are often used as power sources in agriculture. The created vibrations can cause lack of comfort and reduce effective work ...
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Introduction Vibrations include a wide range of engineering sciences and discuss from different aspects. One of the aspects is related to various types of engines vibrations, which are often used as power sources in agriculture. The created vibrations can cause lack of comfort and reduce effective work and have bad influence on the health and safety. One of the important parameters of the diesel engine that has the ability to create vibration and knocking is the type of fuel. In this study, the effects of different blends of biodiesel, bioethanol and diesel on the engine vibration were investigated. As a result, a blend of fuels such as synthetic fuel that creates less vibration engine can be identified and introduced. Materials and Methods In this study, canola oil and methanol alcohol with purity of 99.99% and the molar ratio of 6:1 and sodium hydroxide catalyst with 1% by weight of oil were used for biodiesel production. Reactor configurations include: maintaining the temperature at 50 ° C, the reaction time of 5 minutes and the intensity of mixing (8000 rpm), and pump flow, 0.83 liters per minute. A Massey Ferguson (MF) 285 tractor with single differential (2WD), built in 2012 at Tractor factory of Iran was used for the experiment. To measure the engine vibration signals, an oscillator with model of VM120 British MONITRAN was used. Vibration signals were measured at three levels of engine speed (2000, 1600, 1000 rpm) in three directions (X, Y, Z). The analysis performed by two methods in this study: statistical data analysis and data analysis using Adaptive neuro-fuzzy inference system (ANFIS). Statistical analysis of data: a factorial experiment of 10×3 based on completely randomized design with three replications was used in each direction of X, Y and Z that conducted separately. Data were compiled and analyzed by SPSS 19 software. Ten levels of fuel were including of biodiesel (5, 15 and 25%) and bioethanol (2, 4 and 6%), and diesel fuel. Data analysis by ANFIS: ANFIS is the combination of fuzzy systems and artificial neural network so that it has both benefits. This system is useful to solve the complex non-linear problems in agricultural engineering applications such as systems involved in the soil, plant and air. ANFIS by linguistic concepts can establish and inference non-linear relationship between inputs and outputs. In this research, modeling was generally performed by Toolbox of ANFIS and coding in MATLAB too. Five important and effective factors in modeling were optimized until the best ANFIS model is obtained. The five factors were: type of input fuzzy sets, the number of input fuzzy sets, fuzzy set of output, methods of optimization and the number of epochs. Results and Discussion Based on the total vibration acceleration values for different fuels in different rpm, pure diesel (B5E4D91) had the highest vibration and the lowest vibration was seen in the mixed fuel of B25E4D71. Based on the results, two combined fuel of (B25E2D73, B25E4D71) have the lowest vibration and highest amount of biodiesel fuel (25%). After them, three combined fuels of (B5E2D83, B5E4D81, and B5E6D79) have created more vibration and the lowest amount of biodiesel fuel in this study (5%) has created the greatest amount of vibration. With increasing engine speed, the number of combustion courses and piston shock per unit of time increases. As a result, the engine body vibration increases. The results are consistent with results from other researchers. Conclusion In this study, motor vibration of MF285 tractors, by replacing a portion of diesel fuel with biodiesel produced from canola oil and bioethanol, was investigated. In the beginning, necessary biodiesel fuel was produced by research reactor in biodiesel workshop, and then different percentages of diesel and bio-ethanol were mixed to biodiesel and ten combined fuels were created. Finally the effect of different fuel combinations and different engine rotational speeds on the tractor engine vibrations was studied based on a factorial randomized complete block design and then analyzed and modeled by ANFIS. The results showed that the vibration of pure diesel fuel had the highest vibration. Also, with increasing biodiesel fuel blends, the amount of vibration reduced significantly. Increase in engine speed had direct effect on increasing the amount of vibration. Also by increasing the percent of bioethanol from 0 to 4%, the amount of vibration was reduced then vibration value increased by raising the percent of bioethanol. After modeling and analyzing, our results showed that the best fuel in terms of having the lowest vibration motor was B25E4D71.
Research Article
A. Farhadi; S. Rostami; B. Ghobadian; Sh. Besharati
Abstract
Introduction Nowadays, due to higher environmental pollution and decreasing fossil fuels many countries make decisions to use renewable fuels and restrict using of fossil fuels. Renewable fuels generally produce from biological sources. Biodiesel is an alternative diesel fuel derived from the transesterification ...
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Introduction Nowadays, due to higher environmental pollution and decreasing fossil fuels many countries make decisions to use renewable fuels and restrict using of fossil fuels. Renewable fuels generally produce from biological sources. Biodiesel is an alternative diesel fuel derived from the transesterification of vegetable oils, animal fats, or waste frying oils. Considering the differences between diesel and biodiesel fuels, engine condition should be modified based on the fuel or fuel blends to achieve optimum performance. One of the simplest and yet the most widely used models is the thermodynamic model. After verification of the data obtained by model with experimental data it is possible to generalize the extracted data to an unlimited number of functional conditions or unlimited number of fuel types which saves time and reduces costs for experimental engine tests. Using the second law of thermodynamics, it is possible to calculate and analyze the exergy of the engine.4 Materials and Methods In this work, the zero-dimensional model was used to account for internal energy variations, pressure work, heat transfer losses to the solid walls and heat release. The applied assumptions include: The cylinder mixture temperature, pressure and composition were assumed uniform throughout the cylinder. Furthermore, the one-zone thermodynamic model assumes instantaneous mixing between the burned and unburned gases. The cylinder gases were assumed to behave as an ideal gas mixture, Gas properties, include enthalpy, internal energy modeled using polynomial equations associated with temperature. In this research, the equations 1 to 20 were used in Fortran programming language. The results of incylinder pressure obtained by the model were validated by the results of experimental test of OM314 engine. Then the effects of injection timing on Energy and Exergy of the engine were analyzed for B20 fuel. Results and Discussion Comparing the results of the model with the experimental data shows that there was a good agreement between the model and experimental results. The results showed that advancing fuel injection timing increases the peak cylinder pressure. When fuel injecting occurs before the standard injection timing, the pressure and temperature of the charged air in the cylinder is less than that of the fuel when it is injected at standard injection timing. Thus, ignition delay of the injected fuel extends further. As a consequence, the reaction between fuel and air improves, which prepares a good mixture for burning. When the combustion starts, the rate of heat release increases in the premixed or rapid combustion phase of the combustion process due to the suitability of the mixture of air and fuel and hence the peak pressure of cylinder increases. When the injection timing is retarded, the fuel is injected into charged air that has a high temperature and pressure. Thus, in the injection timing of 10 degrees before top dead center, the maximum of incylinder pressure and temperature are reduced compared to the standard injection timing. By retarding the fuel injection into the cylinder, the indicator availability, the heat loss availability by heat transfer from cylinder walls and irreversibility are increased and by advancing the fuel injection into the cylinder, the indicator availability, the heat loss availability by heat transfer from the cylinder walls and irreversibility are reduced. High temperature will increase the produced entropy, so by advancing the injection timing the produced entropy will increase while the retarding injection timing reduces the produced entropy. Exergy and energy efficiencies increased by advancing the injection timing. At 2000 rpm the total availability and heat loss availability by heat transfer was increased compared to 1200 and 1600 rpm. Conclusion The proposed model was able to predict the pressure and temperature of the cylinder at different injection timings. By advancing the fuel injection timing energy and exergy efficiency and heat loss availability by heat transfer was increased. At 2000 rpm the total availability and heat loss availability by heat transfer was increased.
Research Article
M. Mahmoodi-Eshkaftaki; R. Ebrahimi; A. Ghasemi-Pirbaloti
Abstract
Introduction As reported by Sabetghadam (2005), 53.4, 36.3, 1.1, 8.9, and 0.2% of total energy consumption in Iran consisted of oil products, natural gas, coal, electricity energy, and modern energy sources, respectively. The modern energies included solar, biomass, wind and nuclear. The energy mix has ...
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Introduction As reported by Sabetghadam (2005), 53.4, 36.3, 1.1, 8.9, and 0.2% of total energy consumption in Iran consisted of oil products, natural gas, coal, electricity energy, and modern energy sources, respectively. The modern energies included solar, biomass, wind and nuclear. The energy mix has been evolving towards clean energies. From 1966–2005, the contribution of natural gas increased from 1.3% to 36.3% and the contribution of electricity was doubled from 4.1% to 8.9%. The share of oil products in domestic consumption has dropped from 84.3% to 53.4%. Iran has abundant renewable energy resources, including solar energy, wind power, geothermal energy, and biomass, as well as the ability to manufacture the relatively labor-intensive systems that harness these. By developing such energy sources developing countries can reduce their dependence on oil and natural gas, creating energy portfolios that are less vulnerable to price rises. In many circumstances, these investments can be less expensive than fossil fuel energy systems. Over the past ten years some researches on solar and biomass energy have resulted in development and the establishment of a few small- and medium-scale electricity generation plants, powered via solar and biomass energy. There has also been the development of digesters to increase biogas production. Renewable energy is new to Iran and there is a long way to go. Except for the few afore mentioned projects, small-scale technologies to bring power to remote villages have a better chance of being adopted than those implemented at the national level. Materials and Methods In this research the amount of generated methane (methane content of biogas %) from co-digestion of municipal sewage, kitchen waste, and cow dung was measured in 7 different combinations (treatment). Two important parameters affecting methane production such as volatile solid (VS) and total solid (TS) were measured according to Method 1684 and CEN/TS 15148. Furthermore some environmental conditions such as temperature, pH, EC and some of the most important elements of desired substrate such as amount of C, N, P, K, and SO42- were determined. pH using pH-meter and EC using EC-meter, C using titration method according to Rongping et al. (2010) and N using Kjeldahl apparatus, P using Spectrophotometer, K using Flame photometer, and SO42- using weighting were determined according to Standard Method for the Examination of Water and Wastewater. Methane (CH4) was determined using a multi-function gas detector brand GMI Ltd model GT-42. Its detection ranges were 0–10000 ppm (parts per million), 0–100 % LEL (lower explosive limit), and 0–100 % VOL (volume) in temperature limit -20–50 °C and 0–95% R.H (relative humidity). Results and Discussion The mean amount of methane contents of biogas during the co-digestion of the substrates for all 7 treatments reported in table 1 were 4363.25, 875.13, 169.13, 3424.38, 2911.88, 2714.38, and 193.5 ppm, respectively. Methane contents obtained from municipal waste was the highest among the substrates and after that the combination of 1:1:1 of the substrates was more than the others. The methane content was low in the first seven days of digestion, and thereafter rapidly increased over 85% within 22 days. Totally the highest methane contents of treatments were during 30–35 days of digestion which was agreed with other researches. This can be shown in Fig. 5 that the highest methane content was 10000 ppm and appertain to treatment 1. The results showed that TS and VS of kitchen waste were lower than the other substrates. These findings agreed with Chen et al. (2010) researches in which had been reported the commercial kitchen waste has lower TS and VS contents, possibly because the commercial kitchen waste stream contains food with higher moisture contents such as fruits. Furthermore it can be shown that after digestion, the amount of TS of municipal waste, cow manure, and kitchen waste decreased 46, 57, and 46% respectively, while amount of VS of these substrates decreased 82, 92, and 85%, respectively. The results were similar to Chen et al. (2010) results. They reported that between 58 and 99% of the VS were degraded to methane and carbon dioxide under most feed concentrations. The obtained methane significantly correlated with VS, TS at level of 5 %. The pH of the substrate nearly was constant during the digestion. The results showed that the treatments with more municipal waste had more VS and TS while the treatments with more cow dung had more C/N. Some mathematical models were made between the properties and generated methane. The best empirical model which can estimate amount of generated methane using the properties was a polynomial function. The function coefficients were determined for each parameter by normalizing them. Finally the results show that the model made using difference of VS and TS before and after of digestion had the most accuracy among the models (R2=0.897, RMSE=630, SSE=4.76e+06). Conclusion The results of conducted methane fermentation study on physico-chemical properties of substrates including municipal waste, kitchen waste and cow dung reviled that VS, TS, C/N, P, K, and SO42- affect biogas and methane production. However the correlation between methane contents with VS and TS was more than the other properties and the methane estimation models made using the VS and TS was more accurate than the other models.
Research Article
M. Taki; Y. Ajabshirchi; S. F. Ranjbar; A. Rohani; M. Matloobi
Abstract
Introduction Controlling greenhouse microclimate not only influences the growth of plants, but also is critical in the spread of diseases inside the greenhouse. The microclimate parameters were inside air, greenhouse roof and soil temperature, relative humidity and solar radiation intensity. Predicting ...
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Introduction Controlling greenhouse microclimate not only influences the growth of plants, but also is critical in the spread of diseases inside the greenhouse. The microclimate parameters were inside air, greenhouse roof and soil temperature, relative humidity and solar radiation intensity. Predicting the microclimate conditions inside a greenhouse and enabling the use of automatic control systems are the two main objectives of greenhouse climate model. The microclimate inside a greenhouse can be predicted by conducting experiments or by using simulation. Static and dynamic models are used for this purpose as a function of the metrological conditions and the parameters of the greenhouse components. Some works were done in past to 2015 year to simulation and predict the inside variables in different greenhouse structures. Usually simulation has a lot of problems to predict the inside climate of greenhouse and the error of simulation is higher in literature. The main objective of this paper is comparison between heat transfer and regression models to evaluate them to predict inside air and roof temperature in a semi-solar greenhouse in Tabriz University. Materials and Methods In this study, a semi-solar greenhouse was designed and constructed at the North-West of Iran in Azerbaijan Province (geographical location of 38°10′ N and 46°18′ E with elevation of 1364 m above the sea level). In this research, shape and orientation of the greenhouse, selected between some greenhouses common shapes and according to receive maximum solar radiation whole the year. Also internal thermal screen and cement north wall was used to store and prevent of heat lost during the cold period of year. So we called this structure, ‘semi-solar’ greenhouse. It was covered with glass (4 mm thickness). It occupies a surface of approximately 15.36 m2 and 26.4 m3. The orientation of this greenhouse was East–West and perpendicular to the direction of the wind prevailing. To measure the temperature and the relative humidity of the air, soil and roof inside and outside the greenhouse, the SHT 11 sensors were used. The accuracy of the measurement of temperature was ±0.4% at 20 °C and the precision measurement of the moisture was ±3% for a clear sky. We used these sensors in soil, on the roof (inside greenhouse) and in the air of greenhouse and outside to measure the temperature and relative humidity. At a 1 m height above the ground outside the greenhouse, we used a pyranometre type TES 1333. Its sensitivity was proportional to the cosine of the incidence angle of the radiation. It is a measure of global radiation of the spectral band solar in the 400–1110 nm. Its measurement accuracy was approximately ±5%. Some heat transfer models used to predict the inside and roof temperature are according to equation (1) and (5): Results and Discussion Results showed that solar radiation on the roof of semi-solar greenhouse was higher after noon so this shape can receive high amounts of solar energy during a day. From statistical point of view, both desired and predicted test data have been analyzed to determine whether there are statistically significant differences between them. The null hypothesis assumes that statistical parameters of both series are equal. P value was used to check each hypothesis. Its threshold value was 0.05. If p value is greater than the threshold, the null hypothesis is then fulfilled. To check the differences between the data series, different tests were performed and p value was calculated for each case. The so called t-test was used to compare the means of both series. It was also assumed that the variance of both samples could be considered equal. The variance was analyzed using the F-test. Here, a normal distribution of samples was assumed. The results showed that the p values for heat model in all 2 statistical factors (Comparison of means, and variance) is lower than regression model and so the heat model did not have a good efficient to predict Tri and Ta. RMSE, MAPE, EF and W factor was calculated for to models. Results showed that heat model cannot predict the inside air and roof temperature compare to regression model. Conclusion This article focused on the application of heat and regression models to predict inside air (Ta) and roof (Tri) temperature of a semi-solar greenhouse in Iran. To show the applicability and superiority of the proposed approach, the measured data of inside air and roof temperature were used. To improve the output, the data was first preprocessed. Results showed that RMSE for heat model to predict Ta and Tri is about 1.58 and 6.56 times higher than this factor for regression model. Also EF and W factor for heat model to predict above factors is about 0.003 and 0.041, 0.013 and 0.220 lower than regression model respectively. We propose to use Artificial Neural Network (ANN) and Genetic Algorithm (GA) to predict inside variables in greenhouses and compare the results with heat and regression models.
Research Article
M. Mohammadi Sarduei; H. Mortezapour; K. Jafari Naeimi
Abstract
Introduction Electrical performance of solar cells decreases with increasing cell temperature, basically because of growth of the internal charge carrier recombination rates, caused by increased carrier concentrations. Hybrid Photovoltaic/thermal (PVT) systems produce electrical and thermal energy simultaneously. ...
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Introduction Electrical performance of solar cells decreases with increasing cell temperature, basically because of growth of the internal charge carrier recombination rates, caused by increased carrier concentrations. Hybrid Photovoltaic/thermal (PVT) systems produce electrical and thermal energy simultaneously. PVT solar collectors convert the heat generated in the solar cells to low temperature useful heat energy and so they provide a lower working temperature for solar cells which subsequently leads to a higher electrical efficiency. Recently, in Iran, the reforming government policy in subsidy and increasing fossil fuels price led to growing an interest in use of renewable energies for residual and industrial applications. In spite of this, the PV power generator investment is not economically feasible, so far. Hybrid PVT devices are well known as an alternative method to improve energy performance and therefore economic feasibility of the conventional PV systems. The aim of this study is to investigate the performance of a PVT solar water heater in four different cities of Iran using TRNSYS program. Materials and Methods The designed PVT solar water system consists of two separate water flow circuits namely closed cycle and open circuit. The closed cycle circuit was comprised of a solar PVT collector (with nominal power of 880 W and area of 5.6 m2), a heat exchanger in the tank (with volume of 300 L), a pump and connecting pipes. The water stream in the collector absorbs the heat accumulated in the solar cells and delivers it to the water in the tank though the heat exchanger. An on/off controller system was used to activate the pump when the collector outlet temperature was higher than that of the tank in the closed cycle circuit. The water in the open circuit, comes from city water at low temperature, enters in the lower part of the storage tank where the heat transfer occurs between the two separate circuits. An auxiliary heater, connected to the tank outlet, rises the fluid temperature to the set point. The performance of the designed system has been investigated in different cities (including Tabriz, Tehran, Kerman and Bandar-Abbas) during 4 seasons of year using Transient System Simulation (TRNSYS) program. The performance parameters included electrical and thermal energy generation and solar fraction. Solar fraction, which expresses the share of energy supplied by solar radiation on the collector in total thermal energy consumption, was obtained from equation 1. Results and Discussion The results showed that the average daily electricity generation in the cities for summer and winter were 4.65 and 2.67 kWh day-1, respectively. The annual electricity generation of the designed system is almost constant in the various cities. In winter, in spite of lower solar intensity and sunny hours, lower average temperature of solar cells in Kerman leads to a slightly better electrical performance than Bandar-Abbas. The highest cell temperatures, in Bandar-Abbas between 12 noon and 1pm, were found to be 33, 37, 31 and 25 oC in spring, summer, autumn and winter, respectively. Thermal energy generation was significantly different at various cities and seasons. In winter, the designed system provides a little fraction (below 10 percent) of thermal demands in Tabriz and Tehran. This is mainly because of the low ambient temperature and solar intensity. The PVT system had a maximum average thermal energy of 16 kWh day-1 and solar fraction of 0.5 which were observed in Bandar-Abbas. Tabriz, because of the lowest ambient temperature, had the least thermal energy generation and solar fraction. The maximum average solar fraction obtained in summer was about 60% while its lowest value in winter was 24%. Conclusion In the present study, a hybrid PVT solar water heater with nominal power of 880 W was proposed for application in Iran. The system was comprised of a PVT solar water collector, an auxiliary heater, a pump and connecting tubes. Technical feasibility of applying the proposed system in different cities was investigated using TRNSYS program. The results are summarized as follows: The annual electricity generation of the designed system was almost constant in the various cities. The highest and lowest values of average electricity generation in summer and winter were determined to be 4.65 and 2.67 kWh day-1, respectively. The PVT system had the maximum average thermal energy of 16 kWh day-1 and solar fraction of 50%, which was observed in Bandar-Abbas.
Research Article
Modeling
A. Zareei; R. Farrokhi Teimourlou; L. Naderloo; M. H. Komarizade
Abstract
Introduction Spiral conveyors effectively carry solid masses as free or partly free flow of materials. They create good throughput and they are the perfect solution to solve the problems of transport, due to their simple structure, high efficiency and low maintenance costs. This study aims to investigate ...
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Introduction Spiral conveyors effectively carry solid masses as free or partly free flow of materials. They create good throughput and they are the perfect solution to solve the problems of transport, due to their simple structure, high efficiency and low maintenance costs. This study aims to investigate the performance characteristics of conveyors as function of auger diameter, rotational speed and handling inclination angle. The performance characteristic was investigated according to volumetric efficiency. In another words, the purpose of this study was obtaining a suitable model for volumetric efficiency changes of steep auger to transfer agricultural products. Three different diameters of auger, five levels of rotational speed and three slope angles were used to investigate the effects of changes in these parameters on volumetric efficiency of auger. The used method is novel in this area and the results show that performance by ANFIS models is much better than common statistical models. Materials and Methods The experiments were conducted in Department of Mechanical Engineering of Agricultural Machinery in Urmia University. In this study, SAYOS cultivar of wheat was used. This cultivar of wheat had hard seeds and the humidity was 12% (based on wet). Before testing, all foreign material was separated from the wheat such as stone, dust, plant residues and green seeds. Bulk density of wheat was 790 kg m-3. The auger shaft of the spiral conveyor was received its rotational force through belt and electric motor and its rotation leading to transfer the product to the output. In this study, three conveyors at diameters of 13, 17.5, and 22.5 cm, five levels of rotational speed at 100, 200, 300, 400, and 500 rpm and three handling angles of 10, 20, and 30º were tested. Adaptive Nero-fuzzy inference system (ANFIS) is the combination of fuzzy systems and artificial neural network, so it has both benefits. This system is useful to solve the complex non-linear problems in agricultural engineering applications. ANFIS by linguistic concepts can establish and inference non-linear relationship between inputs and outputs. In this research, generally modeling was performed by using toolbox of ANFIS and coding in MATLAB software. Five important and effective factors in modeling were optimized until the best ANFIS model was obtained. The five factors were: type of fuzzy sets for inputs, number of fuzzy sets for inputs, type of fuzzy set for output, method of optimization and number of epochs. The statistical model was done by using SPSS and in the multivariate regression method. In multivariate linear regression in statistical model, the independent variables were auger blade diameter, rotational speed and the angle of slope of the auger and dependent variable was volumetric efficiency. The factorial test in randomized complete block design was conducted for variance analysis of volumetric efficiency. Mean Comparison of volumetric efficiency in different levels of factors was performed using Duncan' test in 5% level. Conclusion In this study, volumetric efficiency of spiral conveyors was investigated as a function of auger blade diameter, auger rotational speed and slope of transfer. The performance was measured in terms of volumetric efficiency using ANFIS and statistical models with SPSS. The results showed that: Volumetric efficiency almost decreased by increasing of rotational speed, for all three conveyors. Maximum volumetric efficiency in all three spiral conveyors was in the speed range of 100 to 200 rpm. Volumetric efficiency significantly reduced in all three spiral conveyors by increasing in rotational speed and slope of transferring in spiral conveyors. Effect of spiral conveyor diameter on the volumetric efficiency in product transferring was irregular and no specific process is appeared. The correlation coefficient between the actual and predicted values was obtained as 0.98 in ANFIS model and 0.94 in multivariate linear regression with SPSS which showed the ANFIS model was more accurate than statistical model. Comparison between performances of spiral conveyor to transfer the seeds of wheat, with results by other researchers that has been reported for spiral conveyors with the same slope to transfer of corn kernels, was found that the angle effect on volumetric efficiency is quite significant. Therefore, it proves that performances of spiral conveyor are impressed by characteristics of transition material considerably. The maximum volumetric efficiency was corresponded in rotational speed of 100 rpm, inclination angle of 10º, and blade diameter of 17.5 cm that it was approximately 29.11%.
Research Article
H. Bagheri; M. Rasekh; M. H. Kianmehr
Abstract
Introduction Lentil (Lens culinaris medic) is an important and highly nutritious crop belonging to the family of legumes. Lentil is cultivated worldwide but competition with weeds is a problem affecting production and can reduce yield by more than 80%. The study on the separation of impurities in bulk ...
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Introduction Lentil (Lens culinaris medic) is an important and highly nutritious crop belonging to the family of legumes. Lentil is cultivated worldwide but competition with weeds is a problem affecting production and can reduce yield by more than 80%. The study on the separation of impurities in bulk lentils (Euphorbia helioscopia weed, Wild oat weed and etc.) by a gravity separator has an extreme importance. Since no study has been done to date, in this study, the effects of different parameters of a gravity separator (longitudinal and latitudinal slopes, oscillation frequency and amplitude) on the separation of foreign matters in lentil seeds were evaluated. A dimensionless number (v/aω) which shows ration of air current velocity blown to lentil to the maximum velocity of table oscillation, was considered in ratio of separation. Materials and Methods In this research, lentil samples were taken from farms in Ardebil Province (Bileh-Savar cultivar). A gravity separator apparatus was also used for separating impurities from lentil seeds. A Laboratory Gravity Separator Type LA-K (Westrup A/S Denmark) was used to separate impurities from bulk lentils. In this machine, table settings were as follows; longitudinal slope parameters (1°,1.5°, 1.75°, 2° and 2.5°), latitudinal slope (0.5°, 1°, and 1.5°), frequency of oscillation (380, 400, 420 and 450 cycles min-1), and amplitude of oscillation (5 and 7 mm), these settings were all adjustable. Similarly, the instrument had 5 boxes whereby, through proper adjustment, the heavier material was transferred toward the right side of the table and lighter material moved toward the left side. Through proper adjustment of the main parameters of the instrument, the impurities were separated from bulk lentils. Then using an electronic seed counter, five groups of seed which each group containing 100 seeds were counted and selected. Results and Discussion The results of variance analysis of the factorial design with three factors of table settings; (longitudinal slope at 5 levels, latitudinal slope at 3 levels, and frequency of oscillation of the table at 4 levels) are demonstrated in Table 1. It showed the main effect of table settings. Oscillation of frequency, latitudinal slope, and longitudinal slope, the mutual binary effect of latitudinal and longitudinal slope, the mutual binary effect of the latitudinal slope and the frequency of oscillation, the mutual binary effect of the longitudinal slope and the frequency of oscillation and the mutual triple effect of oscillation frequency, longitudinal slope, and latitudinal slope, were significant at the probability level of 1% and the mutual binary effect of the latitudinal slope and frequency of oscillation significant at the probability level of 5%. The results showed that increase of latitudinal slope of table and increase of longitudinal slope from 1 to 2 degrees will increase the separation percentage of impurities from lentil seeds. Moreover, the separation percentage of impurities from lentil seeds to longitudinal slope, under the various latitudinal slope and dimensionless number of (v/aω) and amplitude of oscillation of 5 mm and 7 mm, were investigated. Results showed that in all conditions with increasing of the longitudinal slope from 2^°-〖2.5〗^°, separation percentage of impurities from bulk lentils will decrease. This was due to the fact that under the stated conditions, distribution of seeds on the surface of the table was more homogenous. Note that at the amplitude of oscillation of 7 mm, transference of materials towards the right side of the table output edge was halted and the surface of the table was not fully covered by the fed materials, and separation decreased. The results of the experiment showed that the maximum separation of impurities from bulk lentils was 90.2 percent (v/aω=171). Conclusion 1- Increased latitudinal slope of the table from 0.5° to 1° and longitudinal slope of table from 1° to 2° were resulted in increased separation percentage of impurities from bulk lentils. 2- The results demonstrated that at settings of longitudinal slope of 2°, latitudinal slope of 1°, and frequency of oscillation of 400 cycles min-1, air velocity of 5.7 m s-1 and amplitude of oscillation of 5 mm (v/aω=171), the maximum separation will be 90.2%. In this case, the output lentil seeds contained the least amount of impurities here.
Research Article
H. Javadikia; Y. Nosrati; M. Mostafaei; L. Naderloo; M. Tabatabaei
Abstract
Introduction Biofuels are considered as one of the largest sources of renewable fuels or replacement of fossil fuels. Combustion of plant-based fuels is the indirect use of solar energy. Biofuels significantly have less pollution than other fossil fuels and can easily generate from residual plant material. ...
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Introduction Biofuels are considered as one of the largest sources of renewable fuels or replacement of fossil fuels. Combustion of plant-based fuels is the indirect use of solar energy. Biofuels significantly have less pollution than other fossil fuels and can easily generate from residual plant material. Waste and residues of foods and wastewater can also be a good source for biofuel production. Transesterification method (one of biodiesel production methods) is the most common forms to produce mono-alkyl esters from vegetable oil and animal fats. The procedure aims are reduction the oil viscosity during the reaction between triglycerides and alcohol in the presence of a catalyst or without it. In this study, the method of transesterification with alkaline catalysts is used that it is the most common and most commercial biodiesel production method. In this study, configurations of made hydrodynamic cavitation reactor were studied to measure biodiesel fuel quality and enhanced device performance with optimum condition. The Design Expert software and response surface methodology were used to get this purpose. Materials and Methods Transesterification method was used in this study. The procedure aims were reduction of the oil viscosity during the reaction between triglycerides and alcohol in the presence of a catalyst or without it. Materials needed in the production of biodiesel transesterification method include: vegetable oil, alcohol and catalysts. The used oil in the production of biodiesel was sunflower oil, which was used 0.6 liters per each test in the production process base on titration method. Methanol with purity of 99.8 percent and the molar ratio of 6:1 to oil was used based on titration equation and according to the results of other researchers. The used catalyst in continuous production process was high-purity sodium hydroxide (99%) that it is one of alkaline catalysts. Weight of hydroxide was 1% of the used oil weight in the reaction. Response surface methodology: Three important settings of reactor were considered to optimize reactor performance, which include: inlet flow to reactor, reactor rotational speed and the fluid cycle time in the system. Each set was considered at three levels. The factorial design was used to the analysis without any repeat, there will be 27 situations that because of the cost of analysis per sample by GC, practically not possible to do it. Therefore, response surface methodology was used by Design Expert software. In the other words, after defining the number of variables and their boundaries, software determined the number of necessary tests and the value of the relevant variables. Results and Discussion Three parameters include the inlet flow to reactor, reactor rotational speed and the fluid cycle time in the system were considered as input variables and performance of reactor as outcome in analyzing of extracted data from the reactor and GC by Design Expert software. The results of tests and optimization by software indicated that in 3.51 minutes as retention time of the raw material of biodiesel fuel in the system, the method of transesterification reaction had more than 88% Methyl ester and this represents an improvement in reaction time of biodiesel production. This method has very low retention time rather than biodiesel fuel production in conventional batch reactors that it takes 20 minutes to more than one hour. Conclusion According to the researches, efficiency of biodiesel fuel production in hydrodynamic cavitation reactors is higher than ultrasonic reactors so in this study, the settings of hydrodynamic reactor were investigated so that the settings were optimized in production of biodiesel fuel. Sunflower oil was used in this research. The molar ratio of Methanol to oil was 6 to 1 and sodium hydroxide as a catalyst was used. Three important settings of reactor were considered which include: inlet flow to reactor, reactor rotational speed and the fluid cycle time in the system. The results were analyzed by gas chromatography. The results showed that at 8447 rpm of reactor speed, inlet flow of reactor at 0.86 liters per minute and 1.02 minute of circulation time, the best performance of reactor were created. The flash point, kinematic viscosity and density of biodiesel in this study were 172 °C, 2.4 square millimeters per second and 861 kg per cubic meter, respectively. Maximum and minimum performances of hydrodynamic cavitation reactor in biodiesel production were 6.19 and 1.13 mg kJ-1, respectively.
Research Article
H. Taghizadeh; M. Ziyaei Hajipirlu; V. Khederli; B. Shamsi
Abstract
Introduction Discovering and understanding customer needs and expectations are considered as important factors on customer satisfaction and play vital role to maintain the current activity among its competitors, proceeding and obtaining customer satisfaction which are critical factors to design a successful ...
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Introduction Discovering and understanding customer needs and expectations are considered as important factors on customer satisfaction and play vital role to maintain the current activity among its competitors, proceeding and obtaining customer satisfaction which are critical factors to design a successful production; thus the successful organizations must meet their needs containing the quality of the products or services to customers. Quality Function Deployment (QFD) is a technique for studying demands and needs of customers which is going to give more emphasis to the customer's interests in this way. The QFD method in general implemented various tools and methods for reaching qualitative goals; but the most important and the main tool of this method is the house of quality diagrams. The Analytic Hierarchy Process (AHP) is a famous and common MADM method based on pair wise comparisons used for determining the priority of understudied factors in various studies until now. With considering effectiveness of QFD method to explicating customer's demands and obtaining customer satisfaction, generally, the researchers followed this question's suite and scientific answer: how can QFD explicate real demands and requirements of customers from tractor final production and what is the prioritization of these demands and requirements in view of customers. Accordingly, the aim of this study was to identify and prioritize the customer requirements of Massey Ferguson (MF 285) tractor production in Iran tractor manufacturing company with t- student statistical test, AHP and QFD methods. Materials and Methods Research method was descriptive and statistical population included all of the tractor customers of Tractor Manufacturing Company in Iran from March 2011 to March 2015. The statistical sample size was 171 which are determined with Cochran index. Moreover, 20 experts' opinion has been considered for determining product's technical requirements. Literature and theoretical bases of this study have been collected with research paper tab and the research data has been collected through four researcher-made questionnaires and interview tools. The questionnaire Type 1, used for determining the most important demands and needs of customers based on five choices Likert scale. The questionnaire Type 2 was for gathering data requirements to hierarchical AHP method, and the questionnaire Type 3 was for doing some evaluation about organization's present situation related with competitor's situation based on customer's demands and needs; and the questionnaire Type 4 had been implemented for finding technical requirement weights respect to customer's demands and needs. The reliability of the type 1, 3 and 4 questionnaires determined by Chronbach's Alpha method; after gathering required data for mentioned statistical test, these questionnaires' reliability rates are obtained: 0.768, 0.784 and 0.793, respectively. As well as, the validity of the questionnaires has been examined with content validity method. In this research, for analyzing the gathered data, while taking into account the different stages of QFD method, t- student statistical test was used for identifing the needs and demands of customers, and AHP was used for determining the priority of needs and demands of customers. Results and Discussion The results of one sample t-test for identifying the customer’s most important demands and needs showed that the factors such as: producing low price tractor, the quality of used auto-parts, sustainability and long-lasting the final production (production life and durability), comfort and peace during work, creating operator cabin, easy access to spare components, the amount of fuel consumption, warranty and maintenance, easy access to official repair stations, technical experts and suitable auto-parts, fast respond of brake system during braking and smooth moving identified the important demands and needs of customers. The results of AHP method for determining primary priorities of perceived customers needs and demands revealed as follows respectively: quality of parts, warranty and maintenance, low price, fuel consumption, comfort and peace, life and durability, smooth moving, fast respond of brakes, creating operator cabin and easy access to spare components. Finally, the main demands and related technical requirements have been identified and prioritized with QFD method; the Final results of customer demands and needs by QFD method revealed this prioritization: Quality of Parts, Warranty And Maintenance, low price, Fuel Consumption, Peace and Comfort, Life and Durability, Smooth Movement and lower engine knocking, Fast Respond of Braking System, Creating Operator Room and Easy Access to Components. Conclusion Without any doubt it is obvious that the obtaining customer satisfaction is the most important strategic tool for having successful and highly developed industry in this era. Knowing the customer demands and needs can lead the organization to enhance competitive advantages. This research showed that how could use structured QFD method for identifying prioritization of tractor customer demands and needs for maintain their satisfaction, and identifying importance of each demands, considering the production techniques.
Research Article
H. Sadrnia; M. Khojastehpour; H. Aghel; A. Saiedi Rashk Olya
Abstract
Introduction The high energy consumption is one of the serious problems in poultry industry. The poultry industry consume about five percent of total energy sources in different countries, with consideration of losses, it increases up to 16-20%. In the year 2003 also, the Iranian chicken meat consumption ...
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Introduction The high energy consumption is one of the serious problems in poultry industry. The poultry industry consume about five percent of total energy sources in different countries, with consideration of losses, it increases up to 16-20%. In the year 2003 also, the Iranian chicken meat consumption per capita was 13.3 kg, while in the year 2013 it increased to 25.9 kg (FAO, 2014). It shows that in the diet of Iranian people, the chicken meat has become a strategic food. Poultry industry is one of the biggest and most developed industries in Iran. In the past two decays, mainly due to population growth and increase demand of white meats, it is necessary to change and improve energy efficiency in this industry. Technical efficiency of broiler farms in the central region of Saudi Arabia was analyzed through stochastic frontier approach (Alrwis and Francis, 2003). They reported that many farms under study work lower than their total capacity. In the research, the output was chicken meat weight in the term of the kilogram per one period and the inputs were the number of chicks, feed, the total of all variable expenses and fixed input except chicks and feed and the total cost of fixed inputs including building, equipment and machinery used for the broiler houses. They found that the small and large size broiler farms in the Central Region of Saudi Arabia were produced chicken with mean technical efficiency 83 and 88%, respectively (Alrwis and Francis, 2003). Efficiency measurement of broiler production units in Hamadan province was investigated by Fotros and Solgi (2003). They reported that the minimum, maximum and mean technical efficiency under variable return to scale were 12.7, 100 and 64.4%, respectively. Their results showed that technical efficiency at 16.5 (14 units) and 42.35% (24 units) of farms were more than 90 and 70%, respectively (Fotros and Salgi, 2003). Khorasan Razavi province after Esfahan and Mazandaran provinces is the third largest producer of broilers in Iran. This research was performed because it is necessary to have energy consumption status; also there is a few data about broiler’s energy consumption in Mashhad. In this research, the data of Mashhad’s broilers was analyzed by Data Envelopment Analysis Method. The other objectives of this study were to separate efficient and inefficient units to use energy resource efficiently and determine total energy saving. Materials and Methods This study was performed in 2013 in Mashhad, Iran. The data were collected through interviews and questionnaires from 36 poultry farmers for a growing period of April to May. Input energies were the feed, fuel (gas and gas oil), electricity, labor, equipment and chicken, and the output energies were the chicken meat and the manure. The energy consumption for each element was calculated by multiplied amount of inputs/outputs to energy equivalents. Results and Discussion The total of input and output energies were obtained 125.2, 24.9 GJ/1000Birds, respectively. Energy indices such as energy ratio, energy efficiency and specific energy were determined to be 0.2, 0.019 kg/MJ and 52.55 MJ/kg, respectively. The highest share of energy consumption were 50.84 and 42.43%, for fuel (natural gas and diesel fuel) and feed respectively, the lowest share among the input energies were 0.39 and 0.06%, for chicken and labor respectively. Comparison of energy in three levels of farm sizes (≤15000, 15000-30000 and ≥30000 chicks) showed the energy ratio for large farms were higher than the other levels. Data Envelopment Analysis (DEA) was used to evaluate the poultry efficiency. The results showed that 13 poultry units had average technical efficiency (0.93) in the definition of Constant Returns to Scale (CRS), and 21 poultry units had pure technical efficiency (0.99) in the definition of Variable Returns to Scale (VRS). Conclusion The Fuel (natural gas and diesel fuel) consumption energy had the highest shares of energy consumption; it is because of the low efficient heating equipment in poultry houses and low fuel prices in Iran. Energy efficiency of broiler farms in Mashhad was obtained 0.2 that show low energy efficiency. Improvements in energy efficiency could be achieved by increasing yield or reducing inputs energies.
Research Article
F. Nadi; S. Abdanan Mehdizadeh; O. Nourani Zonouz
Abstract
Introduction The significant of solar energy as a renewable energy source, clean and without damage to the environment, for the production of electricity and heat is of great importance. Furthermore, due to the oil crisis as well as reducing the cost of home heating by 70%, solar energy in the past two ...
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Introduction The significant of solar energy as a renewable energy source, clean and without damage to the environment, for the production of electricity and heat is of great importance. Furthermore, due to the oil crisis as well as reducing the cost of home heating by 70%, solar energy in the past two decades has been a favorite of many researchers. Solar collectors are devices for collecting solar radiant energy through which this energy is converted into heat and then heat is transferred to a fluid (usually air or water). Therefore, a key component in performance improvement of solar heating system is a solar collector optimization under different testing conditions. However, estimation of output parameters under different testing conditions is costly, time consuming and mostly impossible. As a result, smart use of neural networks as well as CFD (computational fluid dynamics) to predict the properties with which desired output would have been acquired is valuable. To the best of our knowledge, there are no any studies that compare experimental results with CFD and ANN. Materials and Methods A corrugated galvanized iron sheet of 2 m length, 1 m wide and 0.5 mm in thickness was used as an absorber plate for absorbing the incident solar radiation (Fig. 1 and 2). Corrugations in absorber were caused turbulent air and improved heat transfer coefficient. Computational fluid dynamics K-ε turbulence model was used for simulation. The following assumptions are made in the analysis. (1) Air is a continuous medium and incompressible. (2) The flow is steady and possesses have turbulent flow characteristics, due to the high velocity of flow. (3) The thermal-physical properties of the absorber sheet and the absorber tube are constant with respect to the operating temperature. (4) The bottom side of the absorber tube and the absorber plate are assumed to be adiabatic. Artificial neural network In this research a one-hidden-layer feed-forward network based on the back propagation learning rule was used to simulate the output temperature of a solar collector. The number of neurons within the hidden layer varied from 1 to 20. The hyperbolic tan- sigmoid and pure-line were used as the transfer function in the hidden layer and output layer, respectively. Minimization of error was achieved using the Levenberg-Marquardt algorithm. To carry out the aforementioned steps, the dataset (105 observations) was split into training (70 observations), and test (35 observations) data. Training sets used to develop models included air velocity, solar radiation, time of the day, ambient moisture and temperature values as inputs with an associated temperature of the collector as outputs. The aim of every training algorithm is to reduce this global error by adjusting the weights and biases. Results and Discussion Compare experimental results with ANN The performance of the three-layer ANN for the prediction of output temperature of flat-plate solar collector by the Levenberg–Marquardt training algorithm was illustrated in Fig. 4. ANN predicted output temperatures with R2 and RMSE of 0.92 and 1.23, respectively. Furthermore, the maximum error in prediction of output temperature of solar collector was 3.3 K. These results are in agreement with Tripathy and Kumar, (2009) those who have predicted the output temperatures of food product in the solar drier using ANN with and RMSE of 0.95 and 0.77, respectively. Compare experimental results with CFD simulation Fig. 6 shows that over the starting length of the absorber plate, there is a variation of the velocity profile which is caused by sharp geometry and it leads to some recirculation of the air in this part of absorber plate. After this part of boundary layers, flow is fully developed and velocity profile becomes smoother and constant. Fig. 8 shows that the predicted temperature was within the experimentally measured temperature. The highest differences between simulated and experimental temperatures were around -2.4K to 4.6K for different time periods. The temperature differences of 4K were reported by Selmi et al. (2008). This disagreement is due possibly to the fact that there are unknown experimental inputs such as turbulence intensity, radiative heat loss from the absorber sheet to the surroundings, Leakage, and measurement tool errors which were not accounted in the model simulations. These losses by radiation are significant at high irradiation levels. This result agrees with studies done in Badache et al. (2012). Thickness of absorber plate and radiation loss, in CFD model, does not take into consideration. For this reason maximum output temperature is seen in maximum radiation which is 12 p.m. While in real condition, it takes some time for absorber plate to get to its maximum temperature. Moreover, the numerical temperature is smaller than the real temperature after 12 p.m. This may occur because of the thickness of metal which keeping the absorbed heat and losing it after awhile. Generally there is a time step hysteresis for the numerical temperature. Conclusion According to this study it can be concluded that the ANN operates better than CFD to predict the output temperature operation. However, ANN method does not give any information about the prediction of temperature distribution and velocity profiles in the solar collector. Although prediction accuracy of the CFD method is less than ANN method, but the provided information on the velocity and temperature profile of the solar collector is still valuable.
Short Paper
Design and Construction
A. Akbarnia
Abstract
Introduction Sugarcane, a plant which sugar is extracted from, is planted in vast areas with hot and humid climate. Brazil is the largest producer of sugarcane in the world. The next five major producers, in decreasing order, are India, China, Thailand, Pakistan and Mexico. Sugarcane is a tropical, perennial ...
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Introduction Sugarcane, a plant which sugar is extracted from, is planted in vast areas with hot and humid climate. Brazil is the largest producer of sugarcane in the world. The next five major producers, in decreasing order, are India, China, Thailand, Pakistan and Mexico. Sugarcane is a tropical, perennial grass that forms lateral shoots at the base to produce multiple stems, typically three to four meters high and about 5 cm in diameter. The total area under sugarcane plantation in Iran (Khozestan Province) is about 80,000 hectares with an average yield of 100 tons per hectare. To increase the yield per unit of land and reduce production costs and move toward sustainable agriculture, mechanization of agricultural operations seems inevitable. Planters are the most important of farm machinery among the mechanization equipment. Sugarcane cultivation is done both by hand and machine. Hand planting operations is laborious and painstaking work and work efficiency is so low and culture costs are so high. In Iran farms, the sugarcane plantation process is carried out manually by the farmers. Considering the climatic conditions, the agricultural soil composition and constitution, and the different plantation pattern used in Iran, the imported planting machines are not suitable for the farming conditions in the country. Moreover, the domestically produced machines, which are mostly based on the imported versions, do not provide adequate performance. Therefore, fabrication of a machine, capable of continuously lifting the sugarcane scions from a container and sending them to a dropper pipe, uniformly and in conformance with the climatic conditions of the sugarcane farms in the country, is of great importance. Materials and Methods In this research, initially, a field study was carried out to identify the problems and shortcomings of imported and copied planting machines in sugarcane farms, such as jamming of the scions conveying mechanism and the existence of unplanted sections in the farm. Subsequently, a new compound seeding unit with unique capabilities for solving the above mentioned problems was fabricated, with the aim of application in sugarcane planting machines. The various components of the system include: 1- Tank split in two pieces and connected to each other by two hinges through the middle and it can adjust to different angles. 2- Tube fall for cuttings scions. 3- Two rows of chain on a conveyor screwed on belt. 4- Number of 9 cups (channels) to receive and transmit cutting scions from the tank and guided them to the falls duct. 5- 18 pcs of metal preservative, the chain screwed to conveyor. 6- Four Number of gears on two shafts in order to drive the conveyor chain. 7- Two shafts, one on top and one another on the bottom of the anchor-conveyors chain. 8- The mechanism of driven Endless belt as a mobile bed to showing the steady rate of falling the scions from the fallen channel. 9- Two variable speeds electromotor to provide the movement of complex distributer and planter’s mobile bed belt. 10- Controlling mechanism of falling number of scion. After preparing and manufacturing the different machine’s pieces, they were installed on the chassis and then different units were prepared and the machine are run. Results and Discussion Therefore, fabrication of a mechanism, capable of continuously lifting the sugarcane scions from a container and sending them to a dropper pipe, uniformly and in conformance with the conditions of the sugarcane farms is of great importance. In the new mechanism, as opposed to the existing seeding units in which the seeding operation is performed lengthwise, planting of the scions is performed in a widthwise pattern. Using the manufactured machine had a great effect on method of tillage and planting. The farm field was changed to a smooth surface in tillage then in planting the scions with installing the two diagonal plate the soil putted on scions and the made furrows for irrigating. Conclusion This mechanism reduces the number of planted scions per hectare, results in a more uniform planting and growth of the scions, and reduces the number of machine trips in the farm, increasing the planter productivity. The seeding unit was fabricated and is presently ready for use in the sugarcane planters.
