On the approach of job creating oriented policy, taking the determinants which affect on the job creation power of investment into account, can play very effective role in enhancing the policies results. The elasticity of substitution and return to scale are two important factors which affect the efficacy of investment in job creation. Theoretically, it could be inferred that the lower the elasticity of input substitution, the higher the effectiveness of investment expenditure in the creation of job opportunities for labor forces. On the other hand, the efficacy of investment in job creation will be increased if there is increasing in the degree of return to the scale of production. This paper aims to investigate the contribution of return to scale and elasticity of substitution to the efficacy of investment in job creation in Iran agricultural sector.
Different econometric methods were applied to analyze the data and to estimate the presented models in this paper. Augmented Dickey Fuller (ADF) method was used to test the stationary of variables and showed that all variables are I (1). The co integration between variables was tested using Jonson Co integration approach. Jonson Co integration test results rejected the hypothesis of no Co integration between the variables of the estimated models. The values of elasticity of substitution and return to scale have been calculated for the agricultural sector by estimating the coefficients of the per capita production function using Calman Filter approach. This approach was also used to calculate the effect of the investment on employment by estimating the coefficients of the labor demand function in the agricultural sector. Next, the contribution of the elasticity of substitution and return to scale to the effect of the investment on employment in the agricultural sector has been estimated using three estimation methods including ordinary least squares, robust least squares, and generalized linear models. Required date, including agricultural sector production, agricultural sector capital, agricultural sector employment, agricultural sector wage index and interest rate were gathered from Iran central bank, and Iran statistics organization during 1974-2012.
The estimation results of per capita production function in agricultural sectors show that the coefficient of labor in estimated per capita production function is negative. This reveals the existence of decreasing returns to scale in this sector during the studied period. The agricultural sector has also experienced low levels of elasticity of substitution during the period and there was no significant fluctuation in the trend of substitution elasticity. According to the estimation of labor demand function for the agricultural sector, variables like investment, production and interest rate have statistically positive effect on labor demand in this sector. Wage index, however, negatively affects the labor demand and employment in the agricultural sector. Estimating the effect of a return to scale and the elasticity of substitution on the employment effects of investment, by robust least square, reveals that one unit increase in the return to scale index leads to 0.02 unit increase in the effecting coefficient of investment on employment in the agricultural sector. The elasticity of substitution, however, has a negative effect on the effecting coefficient of investment on employment, so that one unit increase in elasticity of substitution leads to 0.077 unit decrease in the effecting coefficient of investment on employment in the agricultural sector. Ordinary least squares and generalized linear models estimation also show that a one unit increase in the return to scale index leads to 0.009 unit increase in the effecting coefficient of investment on employment in the agricultural sector. Elasticity of substitution, however, has a negative effect on the effecting coefficient of investment on employment, so that one unit increase in elasticity of substitution leads to 0.06 unit decrease in the effecting coefficient of investment on employment in the agricultural sector. All findings are in line with theoretical expectation and verify the positive role of return to scale and negative role of elasticity of substitution on the employment effects of investment in the agricultural sector.
The policy making the implication of the findings is that the allocation of investment to agricultural subsectors with a higher degree of return to scale and lower degree of substitution elasticity, would enhance the efficacy of investment in job creation in the agricultural sector. Improving factor productivity via integrated the agricultural lands and utilizing new irrigation systems, in this regard, lead to enhance the degree of return to scale and increase the job creation potential of investment in this sector.

Nowadays, changes in cultivation pattern towards drought resistant species are proposed as a solution to tackle drought. To study the effect of irrigation levels and planting date on yield and water use efficiency of Hibiscus sabdariffa L., an experiment was conducted in the research field of agriculture college of Islamic Azad University of Birjand during 2010-2011. Three levels of irrigation (20, 60 and 100 percent evapotranspiration of source plant) as main plots and different planting dates (May 10th, June 1th and June 20th) as sub plots were studied in a split plot experiment with three replications in a randomized complete blocks design. The results indicated that different irrigation levels and planting dates had significant effects on number of flowers per square meter, dry and fresh weight of flowers, total biomass yield and water use efficiency (flower and biomass). The highest number of flowers per square meter (62.42), flower fresh weight (62.50 grams per square meter), flower dry weight (10.30 grams per square meter), total biomass yield (150.3 grams per square meter), water use efficiency of flowers (0.024 gram per) and water use efficiency of biomass (0.532 gram per liter) were obtained from the first planting date i.e. May 10th. Also, the highest number of flowers per square meter (55.88), flower fresh weight (72.40 grams per square meter), flower dry weight (11.46 grams per square meter), biomass yield (142.5 grams per square meter), water use efficiency of flower (0.042 gram per liter) and water use efficiency of biomass (0.897 gram per liter) were recorded for the irrigation level of 20 percent evapotranspiration of the source plant. Irrigation levels and planting dates had no significant effect on flower harvest index. The interaction effect of irrigation levels and planting dates was significant on flower dry and fresh weight, total biomass yield and water use efficiency (flower and biomass). The highest values of these traits were obtained at planting date of 10 May and irrigation level of 20 percent evapotranspiration of source plant. Generally, with regard to the early cold fall and long growth period of Hibiscus sabdariffa, its plantation is not recommended in Birjand climate. According to the results of this experiment, water requirement of this plant was low.

Nowadays, different methods of hydrocolloid extraction has been studied and the effect of these methods has been investigated on functional properties of these hydrocolloids. According to these studies, it has been found that different variables has influence on hydrocolloids properties such as temperature, water to seed ratio, pH, salt concentration and extraction time. “Quince” tree is local tree in Asia and widely grow in north of Iran. The fruit of this tree has seeds which have extractable mucilage on its outer surface. Extraction of “Quince” seeds mucilage always was done by conventional methods and there is limited information about using new technology such as ultrasound on extraction. The objective of present study is to assess the effect of extraction by ultra sound wave in addition to some variables such as temperature and pH on extraction yield and rheological properties of extracted mucilage. In order to obtain optimum extraction yield and apparent viscosity, optimization of “Quince” seed mucilage extraction was done using “Response Surface Methodology” and “Central Composite Rotational Design” and Optimum operating condition of extraction was predicted.
“Quince” seeds were obtained from Gilan ecotype. In order to determine the effect of different parameters on yield (%) and apparent viscosity (mPa.s) of extracted mucilage, three independent variables including temperature (25–55ºC), ultra-sonication time (3–10 min), and pH (6–8) were investigated. Response Surface Method was used to design Experiments. Apparent viscosity of mucilage were measured by rotational viscometer Brookfield at 50 RPM in constant temperature 25ºC. Using regression analysis, a second-order polynomial model was developed for each response. Chemical composition of extracted mucilage was determined using AOAC standard methods.
among investigated variables, temperature and ultra-sonication time had significant effect on extraction yield and viscosity while pH was not significant (p “Quince” seed mucilage showed a non-Newtonian and shear thinning (pseudoplastic) behavior. Extraction yield and apparent viscosity has affected by some extraction parameters such as temperature and ultra-sonication time so optimum yield and viscosity can access with determining suitable conditions of mucilage extraction.

Malt is germinated cereal grain being rich in carbohydrates, proteins and B group vitamins and minerals. Malting is complex biotechnological process that includes steeping; germination and kilning of cereal grains under controlled conditions of temperature and humidity. In this study, two Wheat varieties (Kohdasht, Zagros) were obtained from Jahad-e-Agricultural organization of Golestan province. The preliminary assessment of samples such as viability and physico chemical properties were determined after two months storage. Malts were made from them in laboratory scale, mashed and then physicochemical properties of wort such as hot water extract, color, pH, Brix, reduced sugar, total solid nitrogen and free α-amino nitrogen were measured. Analysis of variance was performed with SAS and the differences among means were evaluated using the Duncan's multiple range tests. The results showed that during malting diastatic power and cold water extract improved and thousand kernel weight and protein content were decreased (P<0.05). The results also confirmed that there were linear relationship between nitrogen content (wheat), diastatic power, cold and hot water extract. Thousand kernel weight (40.78 gr) and cold water extract (20.77%) of malted wheat (Kohdast) was more than Zagros but ash (1.3%), diastatic power (179.91 °L) and total nitrogen (2.18%) of it was less (P<0.05). The results of physico-chemical properties of malted wheat showed that kohdasht variety had more hot water extract (67.154%), reduced sugars (64.192 g/L) and brix (8.25% w/w) but lower total soluble nitrogen (0.742%) and free amino nitrogen (98.585 mg/L) compared to Zagros (P<0.05).

Now days، nutritional labeling of fish edible products and calculation of its fillet yield are important needs for fish processing industries. The present study was done to investigate Determination of chemical composition and fillet yield of silver carp (Hypophthalmichthys molitrix) for grading and nutritional labeling of its products by regression equations. For this purpose 50 specimens silver carp were applied in marketing size and their fillet yield، moisture، lipid، protein، ash and energy content were measured. Then، the relationships between these parameters with total length were considered and type of relationship and equation of them were determined. According to obtained results، the relationship between moisture content with fish total length was in inverse linear regression form (p<0. 05)، while the relationships between lipid، protein and energy content of fillet with fish total length was in positive linear regression form (p<0. 05). In generally these equations was in Y= bX± a form. The relationship between protein content and fish total length was significant but weak. According to obtained results there is not relationship between fillet ash content and fish size. Regarding these results and determining their equations، fish length can be used for fish sorting by sorting machine and then economic calculations and determination of moisture، lipid، protein and energy content by obtained equations were done for each group and finally، nutritional labeling and deciding for processing were done for each group.

Sourdough fermentation by lactic acid bacteria and baker''s yeast with acidification of dough and producing lactic acid and acetic acid has significant effects on quality characteristics of bread. Application of liquid sourdough in bakery industry has attracted much attention due to higher dough yield، ease of transition and one-step process in order to achieve desired texture and flavor characteristics in final product. In the research، Response surface liquid methodology was used to optimize sourdough fermentation for increased acidification. Fermentation time (5. 3- 18. 7 hrs.)، temperature (21. 6- 38. 4 °C)، and dough yield (249. 6- 350. 4) were considered as independent factors according to central composite design and their effects were studied in liquid sourdoughs fermented with Lactobacillus casei subsp casei، Lactobacillus fermentum and Saccharomyces cerevisiae. lactic acid and acetic acid contents and total titrable acidity (TTA) were considered as the main responses. The second order polynomial models satisfactory predicted the effects of variables on acidification properties (R2adj> 0. 80). Statistical analysis showed that all the responses were significantly (P<0. 01) correlated to fermentation time and temperature. Increase in fermentation time and temperature was associated with an increase in lactic acid، acetic acid and TTA and fermentation time was the most affecting factor on acidification. Lactic acid was not affected by dough yield but the lower dough yield caused in high acetic acid content and acidity. Based on response surface and contour plots، the optimum conditions for maximum acidification were: fermentation time (21 hrs.)، temperature (38°C) and dough yield (DY: 325).

In order to study the effect of irrigation interval, Nitrogen (N) fertilization and plant density on yield and yield components of fenugreek (Trigonella foenum-graecum L.), a split-split-plot experiment was conducted in Darmian, Iran in Spring 2010 based on a randomized complete block design with three replications. The main plots were irrigation interval at two levels of 5 and 10 days. The sub-plots were N fertilization at three rates of 0, 75 and 150 kg N.ha-1 from urea source and the sub-sub-plots were plant density at three levels of 22, 33 and 66 plants.m-2. According to the results of analysis of variance, irrigation interval significantly affected traits of pod length and water use efficiency (WUE) for seed and biomass production. In addition, main branch number per plant, pod length, seed yield, chlorophyll index and WUE for seed and biomass production, were significantly affected by nitrogen rate and plant density had significant effect on main branch number per plant and ring diameter. Means comparison showed that as irrigation interval was increased from 5 to 10 days, pod length decreased 8.7%, but WUE for seed and biomass production increased 40.5 and 47.5%, respectively. Also, as N rate was increased from 0 to 150 kg N.ha-1, main branch number per plant, pod length, seed yield, chlorophyll index and WUE for seed and biomass production increased by 23.5, 26.4, 23.2, 67.1, 72.3 and 71.5%, respectively. Moreover, with increasing of density from 22 to 66 plant. m-2, branch number per plant and ring diameter decrased 7.9 and 11.2%, respectively. In total, given the results of the study and the importance of water saving, it is recommended to use irrigation interval of 10 days with the application of 150 kg N.ha-1 and density of 66 plants.m-2 for the cultivation of fenugreek in Darmian, Iran.

Dissolving pulp, generally producing from wood and cotton linter and is determined as high α-cellulose which is widely used by numerus cellulosic products like microcelluloses, nanocelluloses and various cellulose derivatives. Huge attempts have been focused on non-woods as pulping raw materials, due to limitations of the resources of wood and cotton. Extreme exploitation of biomass via extraction and conversion of unsuitable components respect to a special application (non-cellulosic materials in dissolving pulp) is biorefinery purpose. Toward biorefinery approach, in this study Kenaf (Hibiscus cannabinus) stalk pre-hydrolyzed by hot water and the optimum residence time (40min) at 160 oC was selected based on the stalk yield loss (27 wt%) and then subjected to soda-anthraquinone pulping at different alkaline and time levels. Concerning optimum purity and brightness, the pulped biomass under 22 wt% alkalinity at 90 min with 17.8 kappa NO and pulping yield of 65.9 wt% was followed by AD1EpD2P bleaching sequences based on kappa factors of 0.3, 0.4 and 0.45. Pre-hydrolyze treatment revealed that the yield and acidity reduced due to hemicelluloses removal that were increased by longer times which is valuable respected to the biorefinery approach and α-cellulose requirements. Bleaching Kappa factor of 0.45 resulted in: kappa NO. 1, yield 30.6 wt% (based on the kenaf stalk), α-cellulose 94.1 wt%, viscosity 6.4 cP, ash content 0.51%, DP 1670, and brightness 80.9 respectively. Kappa factor increment led to yield (-2.2%) and ash (-0.25%) loss, together with increase in viscosity (+2%), brightness (+4.3%) and degree of polymerization (+360). Therefore, kenaf stalk could be used as a proper non woody feedstock for α-cellulose production.

Some unit operations of food process engineering such as drying consumes a high amount of energy. Therefore, analysis of energy and exergy can be a suitable method to manage the energy consumption of the drying. Hence, in the present research, analysis of energy and exergy for the drying process of lemon verbena leaves was performed.

A cabinet solar dryer was employed to investigate the energy consumption of thin layer drying of lemon verbena leaves. The dryer had a galvanized solar plate collector which had a surface area of 0.75 m2 and to absorb the maximum solar energy, the collector painted with the black color. The collector was set at an angle of 45 degrees relative to the horizon and an electric blower was installed in the bottom of the collector to blow the ambient air through the solar collector and hence, hot air entered the drying chamber to dry the lemon verbena leaves. In order to record the air temperature and humidity in different locations of the dryer, an Arduino board with 8 smart sensors (AM2301, with temperature accuracy of 0.5°C and humidity accuracy of 3%) were used. To obtain the initial moisture content of the leaves, they inserted in an electrical oven for 16 hours at a temperature of 70°C. In order to measure the moisture content of the leaves during drying, they weighted at different times using a digital balance (A & D, Japan with accuracy of 0.001 g).Energy consumption rate of the drying was calculated by Equation (1):Where, Ein: energy consumption rate (kW), : mass flow rate of drying air (kg s-1), cp: specific heat of drying air (kJ kg-1 °C-1), Δt: temperature difference between the ambient air and drying air (°C).Also, the specific energy consumption of drying (SEC) was calculated by Equation (2):Where; SEC: Specific energy consumption (MJ kg-1 of removed water) t: drying time (s), and M: mass of removed water from the drying material (kg).Also, useful power can be calculated from Equation (3):Where; Eout: useful power (kW), ms: Evaporation rate (kg s-1), lg: latent heat of vaporization (kJ kg-1 of water)In order to calculate energy efficiency, Equation (4) was used: Also inlet and outlet exergy were calculated by equations (5) and (6), respectively: Where; T1: Inlet air temperature into the drying chamber (°C), T2: Outlet air temperature from the drying chamber (°C), T0: Ambient air temperature (°C).
Also, Equations (7) and (8) were used to calculate exergy efficiency and loss, respectively:

The results of energy analysis showed specific energy consumption (SEC) increased with increasing of drying temperature and decreasing of air velocity. Accordingly, in the air velocity of 2 m s-1 and the temperatures of 30, 40, and 50 ˚C, SEC were 276.3, 694.7, and 708.0 MJ kg-1 of removed water, respectively. While SEC for an air velocity of 2.5 m s-1 and air temperatures of 30, 40, and 50 ˚C were 266.9, 469.8, and 638.0 MJ kg-1 of removed water, respectively, the corresponded values for air velocity of 3 m s-1 were as 217.0, 391.3, and 501.8 MJ kg-1 of removed water, respectively. Also, the results revealed that with an increase of temperature and a reduction of velocity, energy efficiency reduced, so that the maximum value of energy efficiency observed in an experiment with temperature of 30˚C and velocity of 3 m s-1. Also, the highest value of exergy efficiency obtained in temperature of 50˚C and velocity of 3 m s-1.

A hot air solar dryer was used for drying lemon verbena leaves. Results of specific energy consumption of drying showed a high amount of fossil fuels can be saved by using this dryer. Also, from the aspect of energy and exergy efficiency, using of the dryer in the lower temperature and higher air velocity is recommended.

Cropping pattern optimization is an important strategy in the optimal use of water in agriculture. The present study attempted to develop and evaluate four hybrid models based on maximizing economic return rate and minimizing risk based on risk indices including variance (MVar model), semi-variance (MSVar model), absolute value deviation from mean (MADev model) and conditional value at risk (MCOVaR model). The MCOVaR model is governed by observing the rules, which at a selective confidence level allows determining the best cropping pattern scenario with selective return rate and the lowest risk that can be measured in the decision-making stage. The data used are related to the downstream irrigation network of Ardabil Yamchi Dam and for the 1397-98 crop year. The development of the model in MATLAB is based on nonlinear programming and optimization problem solving using particle swarm algorithm in a multi-objective solution. The highest correlation coefficient in regression of the models with Fourier equation was R2=0.9997 with accuracy (RMSE=0.0011) for MADev model, The results showed that the highest yield of 0.31 belonged to potatoes with a maximum risk of 58% and the lowest yield of 0.13 belonged to the maize plant with a maximum risk of 63%. By calculating 50 scenarios of the best possible cropping patterns in terms of satisfying the target functions and governing conditions, the pareto front of each model was drawn and the table of system income values for risk levels of 20% and 30% was extracted and presented. The results obtained in all models indicate an increase in economic efficiency by increasing the risk level of the system in selecting the optimal cropping pattern and this increase in MADev model is more steep than other models and increasing risk-taking leads to increasing the area under cultivation of plants with more water consumption.