نشریه مهندسی بیوسیستم ایران
سال چهل و ششم شماره 3 (پاییز 1394)

The aims of this study were to assess the energy and economic flows of biodiesel production from olive pomace oil using transesterification method with ultrasound waves. For this purpose biodiesel production from this feedstock were examined through a life-cycle process with considering five main stages of agricultural production, transportation, olive oil extraction, pomace oil extraction and biodiesel production. The results revealed that total energy input were 2601.91 and 3805.04 MJ/ha based on mass-based allocation and economic-based allocation model, respectively. Total energy output (biodiesel as the final outcome) was found to be as 34898.36 MJ/ha. Some energy indicators for production of biodiesel include: energy efficiency, energy productivity, net energy and fossil energy ratio (FER), which were 1.34-0.92 (with no unit), 0.04-0.03 l/MJ, 1413.50-(-) 315.68 MJ/ha, 1(with no unit), respectively for mass-based and economic-based allocation. The share of indirect energy and non-renewable energy were higher than the share of direct energy and renewable energy. Analysis of economic performance indicates that total production value, gross return, net return, benefit to cost (ratio) and productivity were 3.24 million Rial/ha, 1.02 million Rial/ha, 1.01 million Rial/ha, 1.45 (with no unit) and 48.43 l/ million Rial respectively.

Detecting microbial contamination of milk using novel engineering techniques is very worthy. In current study, microbial contamination of UHT milk packages was detected using ultrasonic sensors. Milk packages artificially were inoculated to E. coli in four dilutions and three replications. Monitoring of ultrasonic properties was performed by measuring amplitude and time delay factors. Artificial neural network designed for predicting total count and pH of milk packages based on ultrasonic properties. Results showed that contamination of milk packages for initial dilution 1000 CFU/ml after 7.5 h is capable to detect, and detection period would be increased in conjunction with initial bacterial dilution decreasing. Trained neural network predicted total count and pH values with the coefficient of determination 0.979 and 0.795 against the experimental values. According to the current project, is resulted that microbial contamination is detectable using ultrasonic technique, and to achieve high accuracies, more researches are needed.

Quality evaluation is one of the effective activities in trade, economy and the health of communities. For this purpose, non-destructive methods are increasingly used, as they are faster and more economical in comparison with destructive ones. This study investigated the feasibility of predicting firmness by laser light backscattering imaging system, as a new non-destructive method for one cultivar of peaches. Thus, a laser imaging system was assembled for capturing backscattering images, which consisted of one laser diode at 650 nm. After taking images, essential information of intensity and texture based statistical features was obtained by image analysis techniques, to build two types of calibration models. Non-linear regression and artificial neural network were developed in order to find the best prediction models. Consequently, final models based on the non-linear regression, gave the highest correlation coefficient of r = 0.89 to predict firmness.

A Poly(lactic acid) (PLA) based nanocomposite active packaging has been developed for the controlled release of tert-butylhydroquinone (TBHQ) antioxidant. PLA based active films were loaded with TBHQ (3%wt) or mixture of modified cellulose nanofiber (MCNF) (8%wt) and TBHQ (3%wt) to obtain active and nanocomposite active films, respectively. Release studies indicated that the release rate of TBHQ in 95% ethanol simulant decreased by the addition of MCNF. Faster and higher release of TBHQ occurred at 40 °C according to Arrhenius law. However, the presence of MCNF diminished the increasing effect of temperature on the release rate. The diffusion coefficient (D) for PLA-TBHQ and PLA-MCNF-TBHQ films increased from 6.75 and 4.34 ×10-8 cm2.s-1 to 19.85 and 8.49 ×10-8 cm2.s-1 respectively by increasing temperature from 4 °C to 40 °C. Also the presence of MCNF caused to increase in activation energy of naocomposite active film.

A constant problem in the production, maintenance, and use of agricultural pesticides, is their physical-chemical corrosive properties in contact with machines and equipment. The present study attempted to increase the corrosion resistance of steel parts to agricultural pesticide with the application of appropriate thin TiO2 nanoparticle coatings. This coating was applied on mild steel coupons with different pre-determined thicknesses with the sol-gel method. To determine the rate of corrosion of the coupons, a corrosion simulator system was designed and built. The corrosion properties of coupons were evaluated with two common types of agricultural pesticide in three different concentrations using the weight loss method. The corrosion tests were done in a factorial design with randomized complete block with three replications and three factors: thickness with four levels; type of the pesticide in two levels; and the concentration of pesticide solution in three levels, respectively. The results showed that the coating of TiO2 nanoparticles with a thickness in the range of T3= 1300-1400 nm had the best performance, and improved the corrosion resistance of mild steel up to 89.8%. Furthermore, it was observed that increasing the concentration of agricultural pesticide increases the rate of corrosion on both coated and uncoated coupons.

In this research, the effect of ultrasound-osmotic dehydration process in different conditions on the drying kinetics parameters of rhubarb was investigated. Before dying process, rhubarb samples were placed in contact of ultrasound-osmotic pretreatment and then dried by convection hot air dryer equipped with circulated fan. The results showed that using osmotic pretreatment at 40% sucrose solution along with 30 min sonication could the drying rate to reach maximum. After optimization and determination the best pretreatment for final drying, drying behavior of rhubarb in optimal conditions by ten empirical models such as Parabolic, Midli-kucuk, Silva et alii, Peleg and suchlike was fitted. The modelling results showed that, Midli-kucuk model due to the highest R2 and the lowest χ2 and RMSE were selected as goodness model to predict drying curve of rhubarb. The values of these parameters were estimated equal to 0.9957, 0.0032 and 0.0256, respectively.

The objectives of this study at the first step are to analyze energy consumption and economical profitability in canola production in Mazandaran province of Iran and then to investigate environmental emissions of the production using life cycle assessment methodology. At the next step, the corresponding coefficients are applied to investigate environmental indices in canola production. Required data were obtained through interviews with farmers in the counties of Sari, Neka and Behshahr in the province. For investigating environmental emissions Impact 2002 was applied and a single score was obtained. Then the coefficients were applied. The results revealed that there was no difference between the two methods and the results was completely same.

Light, amber and dark colored kernels were rated by eye on a scale of 3 different genotypes (zh1, zh2 and zh3). The oil content was measured using the Soxhlet extraction method, ranged from 57.26 to 68.29%, for zh1 (light) and zh2 (amber) respectively. Fatty acid compositions were measured using gas chromatography. The main fatty acids were linoleic, oleic and linolenic acids, respectively. Also, no significant difference was found between total protein and crude fiber in colored kernels. zh3 (dark) indicated the highest protein content. The results showed that the different colored kernels had high effect on the physicochemical properties and oxidative stabilities of three walnut genotypes with different colored kernels.

In this study, a three wheel dynamic model refer to a field tractor with an implement was developed to control the tractor in the field accurately. Main difference between a tractor and in-road vehicles is implements connected to the tractor. These implements exert lateral and draft force to the tractor. In order to investigate these kinds of forces, behavior of implements was simulated like a tire. The study was supposed that side slip angle, steering angle and traction of left wheels of tractor are as same as right wheels. In addition a torque was made by draft force moved to the center of gravity of implement. So six wheels traditional model was simplified to three wheels model. The model was simulated by MATLAB software. Results showed that the lateral force and the draft force of implements had effect on the yaw rate and the side slip angle. In addition, controllability of the model was surveyed and results showed that the model have capability of predicting different states of motion in a finite interval of time.

In the present study, optimization of active-blend coating formulation was investigated by response surface methodology (RSM). For this purpose, central composite design with four variables (concentration of carboxymethyl cellulose-pectin, ascorbic acid-citric acid, potassium sorbate and Butylated hydroxyanisole ) were used. Weight loss is selected as responses of model. On the base of minimum weight loss, optimum coating solution was determined. Effects of coating solutions on quality attributes of apples were studied. The coated apples lost their 1.23% weight, while uncoated ones lost of 5% their weight (P

In this study, a laboratory scale continuous plug flow fluidized bed dryer was designed and constructed. A backward-curved centrifugal fan with a 4 kW electromotor was selected based on the maximum pressure drop in the minimum fluidization state and the ability to produce the velocity required for fluidization of the most granular agricultural materials. The fluidization chamber was a rectangular cuboid with 100, 8, and 40 cm in length, width and height, respectively. The solid feed system was consisted of a bin, a screw conveyor, and an electromotor-gearbox. The uniform fluidization and appropriate drying confirmed that it is possible to develop the industrial prototype of the dryer based on the laboratory one. The decrease of solid moisture content along the dryer length was nonlinear. Increasing the inlet solid mass flow rate at constant inlet gas temperature and weir height increased the solid moisture content at the outlet and along the length of the dryer.

An aerobic, meophilic and lipolitic Bacillus.sp bacterium (lipase activity 40 U/ml) was isolated from the olive extract. This isolate was identified based on morphological and biochemical characterization and 16S rRNA gene sequence. Effect of the solid substrate (pomegranate seed ground, grape seed ground and coriander seed ground as a solid substrate), the substrate particle size, moisture content and rotation speed as factors affecting the solid state fermentation was studied.The optimum lipase activity (120 U/ml) was achieved at optimum levels of factors of coriander seed extract (3.0w/w), olive oil concentration (25 g/L), yeast extract (10 g/l), moisture content (70.0%), and agitation rate (170.0rpm) that lipase activity increased to 3.07-fold.

The aim of this study was to evaluate the effects of Echinophora cinerea Boiss and Stachys lavandulifolia Vahl extracts on quality and sensory properties of Doogh, as a dairy drinking, to enhance public health society. For this purpose, different levels of each plant extract was added to the Doogh. Stability, acidity, pH, microbial and sensory properties of Doogh samples were studied during 45 days of storage at 5˚C. The results showed that the acidity of all samples significantly increased during storage. However, the addition of plant extracts could not prevent the phase separation of Doogh, but the survival rate of starters increased significantly. This study revealed that adding these plant extracts in addition to enhance the flavor of samples, were effective to prevent the growth of mold and yeast in Doogh. In conclusion, these aromatic plants extract could be used as natural flavoring in Doogh.