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Ansari S.,Shiraz University | Farahnaky A.,Shiraz University | Majzoobi M.,Shiraz University | Badii F.,Agricultural Engineering Research Institute AERI
Food Biophysics | Year: 2011

Moisture sorption isotherms of figs with and without glucose syrup (at 20% and 40%, w/w) were determined at 5 °C, 25 °C, and 40 °C. A static gravimetric method was used under 0.11-0.84 water activity ranges for the determination of sorption isotherms that were found to be typical type III for control sample. The inclusion of glucose syrup had significant effects on the sorption isotherms, and the moisture content of samples at each a w decreased with increasing temperature. The experimental data were fitted well with two-parameter Brunauer-Emmet-Teller, three-parameter Guggenheim-Anderson-de Boer, and four-parameter Peleg models that all had R 2 of greater than 0.99. The net isosteric heats of sorption were estimated using the Clausius-Clapeyron equation from the equilibrium data at different temperatures. It was found that the addition of glucose syrup significantly increased the amount of monolayer water and the isosteric heat of sorption. Both water activity and isosteric heat of sorption increased with glucose syrup level and the shape and status of sorption isotherms tend to change toward the typical sigmoid shape of most food systems. © 2011 Springer Science+Business Media, LLC.

Ebrahimian H.,University of Tehran | Liaghat A.,University of Tehran | Ghanbarian-Alavijeh B.,University of Tehran | Abbasi F.,Agricultural Engineering Research Institute AERI
Irrigation Science | Year: 2010

For estimating infiltration properties of surface irrigation, some 'quick' and easy methods have been developed. The main objective of this study was to evaluate different 'quick' methods and to compare the obtained results with two new methods proposed based on the Shepard one-point approach. For this purpose, data sets measured in six borders and five furrows were used for evaluating different methods. Using the volume balance equation and estimated infiltration parameters, the total infiltrated volume and advance times were predicted to evaluate the accuracy of estimated infiltration parameters. The results showed that the modified Mailapalli and Elliott and Walker methods provided the lowest errors for both furrow and border irrigations. The Elliott and Walker method predicted advance times with highest accuracy. There was very small difference between the Shepard and new proposed one-point methods. The performance of the Elliott and Walker method was slightly better than the new proposed two-point method for the experimental furrows, while a minor difference was found for the experimental borders. The results also showed that the performance of the Elliot and Walker method would be improved using binomial approximation instead of Kiefer approximation. © 2010 Springer-Verlag.

Ebrahimian H.,University of Tehran | Liaghat A.,University of Tehran | Parsinejad M.,University of Tehran | Playan E.,CSIC - Aula Dei Experimental Station | And 2 more authors.
Irrigation Science | Year: 2013

Increasing water and fertilizer productivity stands as a relevant challenge for sustainable agriculture. Alternate furrow irrigation and surface fertigation have long been identified as water and fertilizer conserving techniques in agricultural lands. The objective of this study was to simulate water flow and fertilizer transport in the soil surface and in the soil profile for variable and fixed alternate furrow fertigation and for conventional furrow fertigation. An experimental data set was used to calibrate and validate two simulation models: a 1D surface fertigation model and the 2D subsurface water and solute transfer model HYDRUS-2D. Both models were combined to simulate the fertigation process in furrow irrigation. The surface fertigation model could successfully simulate runoff discharge and nitrate concentration for all irrigation treatments. Six soil hydraulic and solute transport parameters were inversely estimated using the Levenberg-Marquardt optimization technique. The outcome of this process calibrated HYDRUS-2D to the observed field data. HYDRUS-2D was run in validation mode, simulating water content and nitrate concentration in the soil profiles of the wet furrows, ridges and dry furrows at the upstream, middle and downstream parts of the experimental field. This model produced adequate agreement between measured and predicted soil water content and nitrate concentration. The combined model stands as a valuable tool to better design and manage fertigation in alternate and conventional furrow irrigation. © 2011 Springer-Verlag.

Maftoonazad N.,Agricultural Engineering Research Institute AERI
Recent Patents on Food, Nutrition and Agriculture | Year: 2010

Osmotic treatment describes a preparation step to further processing of foods involving simultaneous transient moisture loss and solids gain when immersing in osmotic solutions, resulting in partial drying and improving the overall quality of food products. The different aspects of the osmotic dehydration (OD) technology namely the solutes employed, solutions characteristics used, process variables influence, as well as, the quality characteristics of the osmodehydrated products will be discussed in this review. As the process is carried out at mild temperatures and the moisture is removed by a liquid diffusion process, phase change that would be present in the other drying processes will be avoided, resulting in high quality products and may also lead to substantial energy savings. To optimize this process, modeling of the mass transfer phenomenon can improve high product quality. Several techniques such as microwave heating, vacuum, high pressure, pulsed electric field, etc. may be employed during or after osmotic treatment to enhance performance of the osmotic dehydration. Moreover new technologies used in osmotic dehydration will be discussed. Patents on osmotic dehydration of fruits and vegetables are also discussed in this article. © 2010 Bentham Science Publishers Ltd.

Asghari S.,University of Mohaghegh | Abbasi F.,Agricultural Engineering Research Institute AERI | Neyshabouri M.R.,University of Tabriz
Biosystems Engineering | Year: 2011

In coarse-textured soils, water and nutrients are lost from the root zone through deep percolation and preferential flow, resulting in poor soil quality. The objective of this study was to investigate the influences of polyacrylamide, cattle manure, vermicompost and biological sludge as soil conditioners on moisture retention and bromide transport parameters in a sandy loam soil. Polyacrylamide (0.25 and 0.5 g kg-1 of air-dried soil), cattle manure (12.5 and 25 g kg-1 of air-dried soil), vermicompost (2.5 and 5 g kg-1 of air-dried soil) and biological sludge (1.7 and 3.4 g kg-1 of air-dried soil) were mixed with the soil and uniformly packed into plastic pans and PVC columns, and incubated in a greenhouse at 0.7 to 0.8 field capacity moisture content (0.143-0.163 g g-1) and at 22 ± 4 °C for 6 months. Pans were used to take core samples to determine soil moisture curve parameters at 7, 30, 60, 120, and 180 days. Bromide breakthrough curves were measured at the same time in the PVC columns. Polyacrylamide significantly increased slope of soil moisture curve at its inflection point as compared to the control and other soil conditioners. Polyacrylamide also prevented early breakthrough of bromide at 7 days by decreasing saturated hydraulic conductivity, compared to the control and biological sludge. All soil conditioners reduced dispersivity parameter in convection-dispersion model. Significant (P ≤ 0.01) positive correlation (r = 0.81) was found between dispersivity parameter in convection-dispersion and mobile-immobile models at the five incubation times. The results showed that polyacrylamide was more effective than other soil conditioners in improving physical quality of sandy loam soils. © 2011 IAgrE.

Vahedi A.,Agricultural Engineering Research Institute AERI
Ecology, Environment and Conservation | Year: 2014

The aim of this study is to consider the energy consuming process and factors influencing rice production in semi-mechanized and traditional systems in Mazandaran Province of Iran. Data used in this study were obtained from farmers using a face to face questionnaire method. Results showed that the total energy used for semi-mechanized and traditional rice production system was 67217.95 and 67356.28 MJ/ha, respectively. Based on the results, irrigation and fertilizer in both systems with 50232 and 610.32 MJ/ha was the most input energy. Total energy output of the traditional method was 127.5 GJ/ha and that of the semi-mechanized was 132.26 GJ/ha. Parallel to the mechanization level of operations that increased, consumption of fuel and machinery energy increased similarly, but the labor and seed energy consumption dropped. The renewable energy in the traditional and semi-mechanized systems was 3168.3 (4.70% total energy) and 2312.1MJ/ha (3.44%), respectively. Energy ratio and energy productivity in traditional and semi-mechanized systems was 3 and 3.08, and 0.111 and 0.116 kg/MJ 116.0, respectively. Nonetheless, net energy gain and specific energy showed that energy efficiency of semi-mechanized systems was more than the traditional system.

Gazor H.R.,Agricultural Engineering Research Institute AERI | Eyvani A.,Agricultural Engineering Research Institute AERI
International Journal of Food Engineering | Year: 2011

Moisture sorption isotherms of red onion slices were determined at 30, 40, 50, and 60°C using the standard gravimetric static method over a range of relative humidity from 0.11 to 0.83. The experimental sorption curves were fitted by seven empirical equations: modified Henderson, modified Chung-Pfost, modified Halsey, modified Oswin, modified Smith, modified BET, and GAB. Also three types of Artificial neural network models: linear, multilayer perceptron, and radial basis function were tested and developed to predict the equilibrium moisture content of onion slices and the selected models were trained by using related algorithms. The modified Oswin model was found acceptable for predicting adsorption moisture isotherms and fitting to the experimental data, based on the coefficient of determination (R 2= 0.991), mean relative percent error (MRE=15.019), and standard error of estimation (SEE=1.371). Besides, multilayer perceptron model with four layers (2: 17: 14: 1) was selected as the best artificial neural network for estimation of onion slices' equilibrium moisture content by considering R 2= 0.993 and good performance. The net isosteric heat of adsorption of moisture was determined by applying the Clausius-Clapeyron equation to the sorption isotherms at different temperatures. The net isosteric heat of adsorption of red onion slices varied between 1.46 and 4.96 kJ/mol at moisture content varying between 2% and 52% (d.b.). © 2011 De Gruyter. All rights reserved.

Tajeddin B.,Agricultural Engineering Research Institute AERI | Rahman R.A.,Technical University of Madrid | Abdulah L.C.,Technical University of Madrid
International Journal of Biological Macromolecules | Year: 2010

Toward the development of biocomposites for packaging applications, the possibility of using kenaf cellulose (KC) was investigated in the production of low-density polyethylene (LDPE)/KC/polyethylene glycol (PEG) biocomposites. First, cellulose was extracted from the cell walls of kenaf-bast fibers. Then, different weights of LDPE, KC, and PEG were blended, and the effects of varying the concentrations of KC and PEG on the synthesis process were evaluated, and the resulting composites were characterized with respect to their mechanical, thermal, biodegradability and water-absorption properties. A scanning electron microscope (SEM) was also used to observe the surface morphology of the samples before and after biodegradation tests. The results showed that the mechanical properties of the biocomposites decreased slightly as the KC content was increased from 0 to 50. wt% in the biocomposite formulation; however, there was a good homogeneity between samples with added PEG. The addition of KC improved the thermal resistance of these biocomposites; PEG also had positive role in the thermal behavior of the composites. Based on a soil-burial test, the biodegradability of the composites showed a clear trend of increase degradation with increasing KC content in the formulation. While water-absorption values for the composites were higher than that of pure LDPE polymer, the addition of PEG to the formulation reduced the water absorption of the composites. © 2010 Elsevier B.V.

Vahedi A.,Agricultural Engineering Research Institute AERI
Ecology, Environment and Conservation | Year: 2016

Achieving self-sufficiency in rice production in Iran is not possible without increasing the area under cultivation, increasing yield and reducing loss. Evaluation of mechanization of rice transplanters in the Mazandaran province showed that by adding 5511 four-row rice transplanters to existing transplanters, the degree of planting mechanization can be achieved to 70 percent. Production of paddy will be increased up to 13432 tons, whose value was estimated 335.8 billion Rials. To promote the mechanization degree of six-row rice transplanters to 30 percent, 574 six-row rice transplanters must be added to the existing rice transplanters that 5807.7 tons rice will be added to rice production of the province, and its value was estimated at 145.2 billion Rials. Copyright © EM International.

Vahedi A.,Agricultural Engineering Research Institute AERI
Ecology, Environment and Conservation | Year: 2016

Rice in Iran, with acreage of more than 630 thousand hectares is considered as the most important crop after wheat, and major acreage of this strategic crop is located in the provinces of Mazandaran and Guilan. Obviously, achieving self-sufficiency in rice production in the country is not possible without increasing the area under cultivation, increasing yield and reducing loss. With increasing 1018 rice combine harvester in rice combine fleet in Mazandaran province, the mechanization degree of harvesting by rice combine can be increased to 80%. With such increase, 10202 tons is added to paddy production in Mazandaran province, and its value was estimated at 255 billion Rials. In this study it was found that the number of rice harvesters in the province is enough for 20 percent of the province's rice harvester. Copyright © EM International.

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