نشریه مهندسی بیوسیستم ایران
سال چهل و ششم شماره 1 (بهار 1394)

In this work، fresh pomegranate peel of three dominant Iranian cultivaris was extracted by soxhlet extraction method via different four solvents. The extracts were analyzed by high performance liquid chromatography (HPLC)، using ultraviolet-visible spectrometric detection. In this study، the extraction yields and presence of seven phytoestrogenic compounds، two tannic acids and their quantities in extracts were evaluated. The compounds were identified and quantified according to their retention times with external standards. Comparison of fresh pomegranate peel of three cultivars indicated that yield of extraction from PoostGoliyeMalaseSaveh variety was more than other two cultivars and the yield of extraction of extracts obtained from the mix solvent was more than three other solvents (p≤0. 05). HPLC analysis indicated besides ellagic and syringic acids، some of phytoestrogens such as Esteriol (up to 7. 45 mg/100 g fresh peel)، Testosteron and α-Estradiol (up to 8. 43 mg/100 g fresh peel) were also found in extract of pomegranate peels. The results show that، between two tannic acids، high value of ellagic acid (up to 103/0 mg/100g fresh peel of post siyahe-Ardestan) were recognized in all extracts.

In this paper a survey to determine the spring and damper settings of ITM285 tractor’s cabin which ensured optimal ride comfort of tractor operator was conducted. Analysis has been done in terms of root mean square acceleration response (RMSAR) in one-third-octave band and International Standard Organization (ISO). Optimization was performed using particle swarm optimization (PSO) method on a 2 DOF modeled in MatLab software for frequencies ranging from 1 to 10 Hz. Obtained results for C1، C2، K1 and K2 were 943 (Ns/m)، 850 (Ns/m)، 3927 (N/m) and 26199 (N/m)، respectively. Modeling tractor cabin using optimized parameters according to ISO 2631-1985، showed 16. 7، 10. 1، 11. 5 and 12. 2 % reduction in rise time، peak time، settling time and max. overshoot of tractor cabin displacement. Therefore، transmitted vibration was reduced and also improve the ride comfort of the tractor operator.

A portable and light pneumatic branch shake system was designed and manufactured in this research for harvesting fruits that can be harvested by shaking branch. Required air flow and electric current are provided for operating system from category containing electrical generator and air compressor on wheelbarrows and portable chassis. Vibration is equipped by programmable logic controller (PLC) for controlling frequency and it is equipped by pantograph system to change amplitude. First farm test was done on olive with three levels of frequency (8، 12 and 16 Hertz) and three times to shaking (5، 10 and 15 seconds) and in constant amplitude of oscillation 5 cm in completely randomized design with four reduplications and second farm test was performed on olive with three levels of frequency (8، 12 and 16 Hertz) and three amplitudes of oscillation (50، 80 and 100 mm) for a fixed period of 5 s in completely randomized design with four reduplication for determining application of branch shake. Some experiments were done for determining static force separating fruit from branch and for comparing it with dynamic force due to performing vibration، as well. The results showed that oscillatory frequency and duration of shaking out have meaningful effect on one percent level on efficiency of shaking system whereas their interaction was not meaningful effect. Comparison of averages showed that increase of the time of vibration didn''t have meaningful effect on percent of harvesting olive in constant oscillation but increase of oscillation in constant time of vibration had meaningful effect on percent of harvesting. Also the result of indicator was based on meaningful effect of amplitude of oscillation on falling olive. And by comparing averages، it was given that falling olive is increased with increasing frequency in constant amplitudes of oscillation. Also، it was not observed meaningful differences between percent of falling olive with increasing amplitude of oscillation from 50 mm to 80 mm in constant frequencies. But when amplitude of oscillation increases from 80 mm to 100 mm، the percent of falling olive meaningfully increases. Finally، concerning by performing 16 Hz frequency and 100 mm amplitude of oscillation for 5 s، 90 percents of olive were separated from branches، therefore they were selected as the best amplitude، frequency and time of vibration.

A mixed solar dryer with a specific mechanism to vary the tilted angle of collector، is utilized to fulfill all tests. The efficiency of the dryers is low because of various reasons such as heat loss of air in an open flow circuit. Getting air back toward the air inlet of dryer can increase the efficiency of dryer and decrease drying process period. A new mechanism considered for dryer which controls the percentage of air recirculation. It contains two dampers which embedded in return air channel of dryer. In order to investigate the effect of air recirculation on energy consumption of drying and dryer efficiency، thin layer of tomato slices are dried in three levels of air flow rate (0. 018، 0. 036 and 0. 054 m3/s) and four levels of air recirculation percentage (0، 50، 75 and 87. 5%). Total experiments were achieved in the beginning of autumn season to reach the moisture content of 12% (w. b) of the samples. The results illustrated the minimum of energy consumption and the maximum of efficiency was provided when 75% of air flow was got back to the inlet of dryer.

In this paper the energy and exergy analyses in chamber drying process of thin layer drying of tomato in a forced solar drying was investigated. The experiments were carried out with two thicknesses of 5 and 7 and two airflows 0. 5 m. s-1 and 1 m. s-1. During the experimental process، ambient temperature was between 22 and 36، air relative humidity between was 14 and 50، and solar radiation ranged from 150 to 850 W. m-2. The effects of drying variables on energy utilization، energy utilization ratio، exergy loss and exergy efficiency were studied by applying the first law of thermodynamics. In chamber drying at airflow of 1 m. s-1 and thickness of 5mm،the values of energy utilization، energy utilization ratio، exergy loss and exergy efficiency varied from 6. 62 to 152. 72W، 0. 02 to 0. 45، 2. 42 to 32W and 32 to 80، Respectively. In addition، the results showed that both energy utilization rate and exergy loss efficiency of the drying chamber decreased with increasing drying mass flow rate and drying thickness while the exergetic efficiency and energy utilization of the drying chamber increased.

Mechanical damagesin theprocessof harvestingandpost-harvest are the most important reason in Cucurbits losses. It causes the tissue destructionand consequentfruits decay. Because of difference in the mechanical strength of flesh and skin of cantaloupe، internal bruising are more usual damages with no visibility. This type of injuriesis hard to predict byanalytical methods. In this study،the mechanical properties of skin and flesh were determined by individual experiments and then finite element model was developed by ABAQUS software. The applied displacements on model were equal to 5. 5، 11 and 16. 5 mm or 10، 20 and 30% of final deformation، respectively. The analytical results showedthat the internal tissue of fruit got to yield in 20%of whole displacementor in 90N force and the internal failure were occurred that it was not visible in the surface of fruit. The model was verified by the comparison of force-displacement graph from experimental data and FEM results. High correlation (R2=0. 983) between the predicted force and the actual force showed the validity of FEM model.

In this study، wasinvestigated the effect of two thickening agents، carboxymethyl cellulose (CMC) and guar on the rheological properties of set fruit yogurt. Viscoelastic modulus (G''، G'')، apparent viscosity and complex viscosity increased and loss factor decreased by increasing carboxymethyl cellulose and guar content up to 0. 2% and 0. 06% respectively. However، in the concentrations greater than these amounts، the contradictory results were observed. Also by adding CMC and guar to fruit yogurt، syneresis and water holding capacity decreased and increased respectively. In spite of possitive effect of two thikening agents on rheological properties، addition of mixture of them had negative effect. By increasing of different proportion of CMC in constant concentrations of guar (0. 02% and 0. 04%) no synergistic effect on improvement of three-dimensional yogurt structure was observed and rheological properties and water holding capacity weakened and syneresis increased.

In modern agriculture، image processing technique is used for mechanization and intelligent machines instead of humans. One of them is identifying varieties of plants and fruits. Identifying plant varieties is important in Plant eugenic programs. Visual examination of plant leaves and fruits are the common processes for this aim. Identification and classification of plants using machine vision techniques can be performed more quickly. In this study، four varieties of apple، Granny Smith، Golab Kohans، Gala، and Delbar-astyval were studied. After collecting leaf samples، the images of leaves were captured and then color، texture، and morphological properties from each image were extracted and adaptive neuro - fuzzy inference system (Anfis) was used for classification. The results showed that ANFIS was able to successfully classify leaves with input and output membership functions، respectively، linear and triangular and hybrid learning method in grid partitioning FIS mood with 95. 83% accuracy.

Low density polyethylene films incorporating different types of organically modified nanoclays were prepared. Physical، surface morphology and mechanical properties of the films were analyzed by x-ray diffraction pattern، scanning electron microscopy and tensile strength (TS) and length increase until fracture point (E) parameters، respectively. Colony counting method was used to investigate anti-microbial activity of the resulting films. X-ray diffraction pattern showed layered structures for the most of the produced films. It was found that Cloisite 20A nanoclay produce a smooth and uniform surface in the films due to a good compatibility with low density poly ethylene matrix. Mechanical properties of the films were not significantly influenced by the addition of nanoclays into the polymeric matrix، although there was a little improvement. Microbial results showed that Cloisite 15A and 20A films at concentrations of 6% exhibited a good anti-microbial activity. All nanoclays at any concentrations tested in this study showed anti-microbial activity against E. coli.

One of the best applications of automated navigation systems is the use of automatic steering systems in agricultural vehicles. In this research، a machine vision algorithm was designed، based on image acquisition from a camera mounted on front of acombine harvester cab fordetection of its forward path. After filtration and optimization of the image، Hough transform was utilized for extracting the path as a line. Then lateral and angular deviations from the path obtained as main inputs for the automatic guidance system of combine harvester. The algorithm was tested in 7 lateral and 7 angular deviation treatments with three replications. The tests were carried out under different conditions of day light. Comparison of the values extraction by the image processing algorithm with angles and deviations measured manually showed that the algorithm is able to detect the designed line with an accuracy of 98%.