M. Porabolghasem; A. Ghazanfari Moghaddam; F. Mozafari ghoraba
Abstract
IntroductionKnowledge of mechanical and viscoelastic properties of agricultural material will be helpful in the transportation and processing of these materials. Giant reed grass, also known as wild cane, is a tall, perennial, bamboo-like, grass that grows in wet areas. The giant reed grass can ...
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IntroductionKnowledge of mechanical and viscoelastic properties of agricultural material will be helpful in the transportation and processing of these materials. Giant reed grass, also known as wild cane, is a tall, perennial, bamboo-like, grass that grows in wet areas. The giant reed grass can flourish in a wide variety of soils, including coarse sands, gravelly soil, heavy clay, and river sediment. This grass attains heights of 7 m and once established the stems can reach a thickness close to 3 cm. The stems of giant reed grass are used for different purposes. Traditionally the stems are used in the villages for fencing, roofing, and producing handcrafts. The modern uses of the giant reed stems include plywood, composites panels and paper production. The giant reed stems are not uniform and are made from many nodes. The number of nodes and the distance between nodes can affect the mechanical properties of the stems. In order to attain a suitable use of the stems in various industries, the physical and mechanical properties of the stems must be determined. Knowledge of mechanical and viscoelastic properties of agricultural material will be helpful in transportation and processing of these materials. The purpose of this research was to determine some relevant mechanical properties of the stems of giant reed grass with different nodes and moisture contents.Materials and MethodsIn this research, different mechanical and viscoelastic tests were performed on the stems of cane at various levels of moisture and number of nodes. The Burger-Voigt model with different number of elements was also used to model the creep behaviors of the stems. The cane stems were cut and divided to three groups of two, four, and six-node stems. The moisture contents of the stems were adjusted to three levels of 30, 40 and 50% (w.b.). After preparing the stems the mechanical tests were performed using an Instron testing machine with a three-point support. The creep tests were done by hanging a 10 kg weight at the middle of each stem. The experiments were done using factorial tests based on completely randomized design. The Young module, toughness, and the yield points of the stems were measured by the three-point method. These parameters were obtained from the stress-strain curves of the three-point compression bending tests. The results showed that the Young module was affected by both moisture and the number of nodes, but there were no interaction effects. The creeps of the stems under 10 kg loading were modeled using 3 to 5 elements Burger-Voigt models. In these models a combination of springs and dashpots are used to represent the stems. The curve fitting was performed using the MATLAB software and the goodness of fitness was verified using the fitted curves and calculating the coefficient of determinations.Results and DiscussionThe results by investigating the graphs and the ANOVA tests showed that the Young module was significantly affected by both moisture and the number of nodes. The obtained Young module for cane stem ranged from 572-1268 MPa. Both yield point and toughness were affected by both moisture and the number of nodes and their values were 65-250 N and 0.016-0.132 J.m-3, respectively. The creep test results indicated that the maximum deformation and maximum time for of the interaction of the two factors was insignificant. The maximum deformations ranged from 2.1-42.5 mm, and the maximum time for reaching the final deformation was 12.5-75 minutes for various moistures and the number of nodes combinations and showed that the 5-element Burger was best for explaining the viscoelastic behavior of cane stems (R2>0.97).ConclusionIn this research, some mechanical properties of the giant reed grass stems were measured and the creep behavior of the stem was modeled using 3-5 elements Burger-Voigt models. The results indicated a decrease in the Young module of the stems with increase with moisture content and increase in the Young module with increase in the number of nodes. On the other hand, the elongation of the stems increased with both number of the nodes and the level of moisture. The 5-element Burger-Voigt model was best fitted to the creep data.
M. H. Aghkhani; M. Baghani
Abstract
The eggshell of birds, as a natural shield and package, protects the tissues inside it from microbial and mechanical damages. Proper intake of calcium, as an important and effective factor in increasing the strength and quality of the eggshell, could reduce complications. In this paper, the effect of ...
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The eggshell of birds, as a natural shield and package, protects the tissues inside it from microbial and mechanical damages. Proper intake of calcium, as an important and effective factor in increasing the strength and quality of the eggshell, could reduce complications. In this paper, the effect of dietary calcium at five different levels on engineering features of Japanese quail eggs in a in their first laying period was investigated. The values for an average of mass, volume, specific mass, shell thickness, major diameter, central diameter and rupture force along the longitudinal and transverse axes were measured. Rupture energy or toughness, slope of the rupture curve (hardness), deformation along the longitudinal and transverse axis to the point of rupture as well as longitudinal and transverse deformation of 450 tested quail eggs (3 period of time, 5 treatment of calcium, 5 replication, 6 observation) were measured. The characters of the specific mass, shell thickness, rupture force, and slope of the rupture curve of quail eggs indicate the strength of quail egg. In this study, variations in all parameters indicating shell strength at different levels of dietary calcium were consistent with each other. Five different treatments with 1.5%, 2%, 2.5%, 3%, and 3.5% calcium content were supplied for the study. By increasing the calcium content of the quail diet from 1.5 to 3 wt%, the volume and weight of quail eggs dropped and shell thickness was reinforced. According to the results, the shell strength of quail eggs along the transverse axis was slightly less than the longitudinal axis, but the flexibility and energy required for quail egg rupture were much greater across the longitudinal axis.
M. Ghasemi; M. Khojastehpour; M. H. Aghkhani
Abstract
Evaluation of mechanical and electrical properties of agricultural products plays an important role in equipment design and optimizing post-harvest operations. Among the crops, tomato and its products are the major processing industries in the world and its economic importance is increasing. Considering ...
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Evaluation of mechanical and electrical properties of agricultural products plays an important role in equipment design and optimizing post-harvest operations. Among the crops, tomato and its products are the major processing industries in the world and its economic importance is increasing. Considering the importance of the quality and various post harvesting uses of tomato, the evaluation of mechanical properties including rupture force and deformation and the work done to establish the rupture of two tomato cultivars (Petoearly CH and Newton) were studied under penetration test based on the electrical conductivity. These properties were measured at three levels of 1, 3 and 5 days after harvesting. The evaluated mechanical properties of both cultivars were decreased by increasing the storage time. Interaction of cultivar and time were significant at the 1% level, for all mechanical parameters except the deformation failure in both cultivars. The electrical conductivity of both cultivars was decreased by increasing the storage time. Interaction of cultivar and time on the electrical conductivity of both cultivars were significant at the 1% level. Significant relationships were found at the 1% level between electrical conductivity and mechanical properties except for deformation of Petoearly CH cultivar. Among the mechanical parameters, rupture forces and rupture works of both cultivars were highly correlated with the electrical conductivity.
S. Kordi; A. Fadavi; M. Eskandari; M. Barari; M. Rafiee; A. Ashraf Mehrabi
Abstract
Mechanical properties of grain are influenced by various factors including soil nutrients and grain moisture content at harvest time. In order to reduce mechanical losses, the design of different processing operations should be performed based on the knowledge of factors influencing the mechanical properties. ...
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Mechanical properties of grain are influenced by various factors including soil nutrients and grain moisture content at harvest time. In order to reduce mechanical losses, the design of different processing operations should be performed based on the knowledge of factors influencing the mechanical properties. The effects of urea fertilization methods and grain moisture content at harvest time on mechanical properties of dried corn were investigated in a field experiment as a strip split plot with four replications based on randomized complete block design at Khorram Abad Agricultural Research Station in 2010. The investigated factors were urea fertilization methods (urea foliar application and urea side-dress application), grain moisture content at harvest time (20, 30 and 40%) and four corn hybrids (NS 640, Konsur 580, Jeta 600 and control SC 704). The moisture content of dried grains due to different absorption property of the treatments was about 7±1 percent. The results showed that the interaction of fertilization methods and hybrid was significant (P < 0.05) for grain toughness. However, the grain moisture content at harvest time had significant effect on all studied traits except on grain firmness. The highest maximum fracture force, displacement at the maximum rupture force, energy consumption at maximum force point, specific deformation, rupture power and toughness were obtained at 20% grain’s moisture content Also, the results showed that NS hybrid had the highest maximum rupture force (219 N), displacement at the maximum fracture force (0.37 mm), energy consumption at maximum force (42.51 mj), rupture power (3.89 . 10-3W) and toughness (0.33 mj mm-3).
K. Hedayati; B. Emadi; M. Khojastehpour; Sh. Beiraghi-Toosi
Abstract
Sugar, which can be extracted from sugar cane and sugar beet, is one of the most important ingredients of food. Conducting more research to increase the extraction efficiency of sugar is necessary due to high production of sugar beet and its numerous processing units in northern Khorasan province. In ...
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Sugar, which can be extracted from sugar cane and sugar beet, is one of the most important ingredients of food. Conducting more research to increase the extraction efficiency of sugar is necessary due to high production of sugar beet and its numerous processing units in northern Khorasan province. In this research, the effect of temperature, time and the frequency of ultrasonic waves on mechanical properties of sugar beet and its extraction rate of sugar in moisture content of 75% were studied. In this regard, an ultrasonic bath in laboratory scale was used. The studied parameters and their levels were frequency in three levels (zero, 25 and 45 KHz), temperature in three levels (25, 50 and 70 ° C) and the imposed time of ultrasonic waves in three levels (10, 20 and 30 min). Samples were prepared using planned experiments and the results were compared with control sugar beet samples. A Saccharimeter was used to measure the concenteration of sugar in samples. Two different types of probe including semi-spherical end and the other one with sharpened edges were used to measure mechanical properties. The studied parameters of frequency, temperature and time showed significant effect on sugar extraction and their resulted effect in optimized levels revealed up to 56% increase in sugar extraction compared with control samples. The obtained values of elastic modulus and shear modulus showed a decreasing trend. The obtained values of total energy of rupture, the total energy of shear, the maximum force of rupture, and the yield point of rupture showed an increasing trend. The frequency had no significant effect on the yield point of rupture and shear force.
E. Velayati; B. Emadi; M. Khojastehpour; M. H. Saeidirad
Abstract
The study of mechanical properties of Berberis not only is useful for design and optimization of transportation, processing and packaging equipment but also can prevent mechanical injuries and losses. In this study force, deformation, energy and toughness were measured at different moisture content levels ...
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The study of mechanical properties of Berberis not only is useful for design and optimization of transportation, processing and packaging equipment but also can prevent mechanical injuries and losses. In this study force, deformation, energy and toughness were measured at different moisture content levels including 70-76, 45-50, 25-30 and 7-10 percent (w.b.). The decrease of moisture content caused increasing rupture force from 1.387 to 2.679 N, decreasing shape deformation from 3.387 to 2.413mm, increasing toughness from 4.297 to 8.220 J/cm3 and decreasing rupture energy from 0.921 to 0.661mJ. Effects of loading speed, force orientation and their interaction were investigated on just fresh Berberis fruit. It was indicated that only force orientation was effective on all investigated properties except toughness. The moisture content was identified as an effective parameter on terminal velocity. It decreased from 9 to 4.5 m/s with decrease of moisture content from 76 to 7 percent (w.b.).
