JOURNAL OF AGRICULTURAL ENGINEERING RESEARCH
Year:2015 | Volume:16 | Issue:3|Papers Count:9

Estimation of hydraulic conductivity is a basic requirement in the design and implementation of underground dams. Evaluation of the materials used in the body of the underground dam in accordance with the standards and principles of design is essential. The question is whether experimental study of the materials used in the core of underground dams considering hydraulic conductivity parameters can produce an appropriate and easy model for estimation of saturated hydraulic conductivity. A new method was developed to prepare nine cohesive soil samples from a physical model of square cross-sections of three Plexiglass boxes having dimensions of 20 ´ 20 ´ 30 cm and a total height of 90 cm were used. The water level could increase toa head of 2 m on the model. The data was recorded at the 0.5, 1, and 1.5 m water heads. Stepwise regression was used to obtain data and present an equation for the saturated hydraulic conductivity coefficient. Two relationships for hydraulic conductivity of compacted soils were developed from the data. The secondary porosity was calculated according to Chapuis theory and nonlinear regression using ksat as a function of the secondary porosity exponent was introduced. The ksat curve and Srcwere drawn in linear formin a graph where axis x = w (soil moisture) and axix y = ρw/ρd. The charts demonstrate that Src and ksat are dense sticky with appropriate estimates to obtain lift.

Autumn sowing of sugar beets for harvesting the root yield the following spring is possible in some regions of Iran. Autumnal beets effectively conserve irrigation water because they make use of precipitation during the autumn and winter months and do not grow during the warm summer periodn. The presents study determined the water-use efficiency of autumn-sown sugar beets and investigated the best irrigation scheduling for the Mashhad plain. Testing was carried out during the 2013-2014 growing season at the Agricultural Research Center of KhorasaneRazavi province using a randomized complete block design with a split plot arrangement and four replications. This experiment examined with three irrigation intervals (7, 10 and 14 d) as the main plot and four irrigation levels (50%, 75%, 100%, and 125% of water content of field capacity) as subplots. The results showed that the yields of roots, dry matter, sugar, and white sugar showed no significant difference for irrigation interval, but that irrigation level had significant effect on yield at the 1% level. The best irrigation water-use efficiency for the yield of conversion to white sugar as the final economic product of sugar beet cultivation was achieved at the 75% and 100% irrigation levels using the 14 d irrigation interval. The results of this project for the Mashhad plain under similar climatic conditions indicates that autumn-sown sugar beets should be irrigated every 14 d at 75% to 100% of field capacity. This irrigation schedule decreased irrigation costs (33%), conserved irrigation water (18%), and achieved maximum irrigation water-use efficiency compared with the 7 d irrigation interval.

Water and energy resources are limited; however, water and energy consumption for production of agricultural crops is increasing to meet the food demands of a growing population. The present study compared the energy and economic productivity of sprinkler irrigation with surface irrigation when groundwater is used as an irrigation source. The study used data on irrigation systems and yield of crops cultivated on the Qazvin plain in 2011. The data was obtained by survey from regional farms, design plans for the irrigation systems, and the Qazvin Agricultural Organization. Results showed that maximum and minimum energy productivity of sprinkler irrigation were 9 and 1.3 kg/kWh for wheat, 7.79 and 2.09 kg/kWh for barley, 8.64 and 1.09 kg/kWh for corn, and 3.74 and 3.37 kg/kWh for alfalfa, respectively. The values for surface irrigation were 13.7 and 2.5 kg/kWh for wheat, 20.28 and 2.93 kg/kWh for barley, 15.2 and 1.5 kg/kWh for corn, and 6.3 and 0.3 kg/kWh for alfalfa, respectively. The energy economic productivity for surface and sprinkler irrigation systems for wheat was greater than for the other three crops. The results also showed that energy productivity for the conjunctive use of surface and groundwater for irrigation was greater than for the sole use of groundwater.

Proteins and polysaccharides are suitable sources for the production of edible film. In this research, whey protein isolate was combined with pullulan at different ratios (30:70, 50:50, 70:30). The film was prepared using the casting method. The mechanical properties (tensile strength, elongation at break) and physical properties (moisture content, solubility in water, water vapor permeability, thickness, total color difference) of the film were evaluated. The results showed that water vapor permeability decreased solubility in water for the film with the 50:50 ratio. The tensile strength and total color difference was highest at this concentration. There was no significant change in moisture content. An increase in pullulan increased elongation at break and decreased thickness. Scanning electron micrography of the film showed a homogeneous structure of the composite film without signs of phase separation between film edges. This indicates that the two components were compatible.

Knowledge of the attributes of a cultivar is important to selection of the appropriate cultivar for modern olive culture. These include productivity, resistance to pests and natural conditions, high oil content, oil quality, size and shape of fruit, and high proportion of meat to core. The type and amount of fatty acid in olive oil determines its quality and the economic value of the oil. The composition of olive is significantly affected by the cultivar and climatic conditions. The present study determined the physical and chemical characteristics of olive and olive oil extracted from two Iranian varieties of olive (Zard and Dezful), both grown in the regions of Shiraz and Kazeroon, two major olive producing areas in Fars province. After determining the physical characteristics of the fruit, the olive oil was mechanically extracted. Physical characteristics of the fruit (weight, density, length, diameter of fruit and core, and meat-to-core ratio) were recorded. The fatty acid composition of the oil was determined by gas chromatography. The results showed that the physical and chemical properties of both cultivars were in accordance with national and international standards. The Dezful cultivar showed a longer length of core, but there were no significant differences between cultivars for other physical characteristics. The length of fruit in Shiraz and the meat-to-core ratio was higher than offruit in Kazeroon. There was no significant differences between areas for the other physical characteristics. The biochemical indicators between cultivars indicated that the oleic, stearic, and arachidic acid content of the Zard cultivar was higher than for the Dezful cultivar and the palmitic, palmitoleic, and linoleic acid content of the Dezful was higher than the Zard. There was a positive correlation between oleic acid content and temperature. Shiraz olives had the highest oil and oleic acid contents and the linoleic acid, palmitic, and palmitoleic acid content of Kazeroon oliveswere higher. The Zard cultivar in Shiraz had the highest oleic acid content. The superior quality of the Zard cultivar in Shiraz, which had the highest oleic acid content (74.2%) and lowest linoleic acid content, recommends it as the best variety. These results indicate that the quality of the olive oil depends both on the olive cultivar and the geographical location.

The use of essential oils and extracts of medicinal plants for thefood, feed, and pharmaceutical industries is growing in response to their medicinal, antifungal, antibacterial, and antioxidant properties. The inhibitory effect of nettle and Mentha piperita on the growth of Aspergillus flavus and decrease in aflatoxin B1level was studied. Essential oils (62.5, 125, 250, 500 and 1000 mg/l) and aqueous, ethanol, and 70% ethanolextracts (500, 1000, 2000, 4000 and 6000 mg/l) of the plants were testingfor reducing A. flavus growth and AFB1content in a liquid culture. The AFB1 content was evaluated using high-performance thin-layer chromatography. Essential oil of M. piperita and nettle at the 1000 mg/l concentration decreasedthe dried mycelia weight 79.40% and 53.30% and decreased AFB1production 88.25% and 57.3%,respectively. The extracts of M. piperita were stronger thannettle for reducing AFB1 content and mycelial growth; the ethanol extract of M. piperita at 6000mg/l decreasedmycelial growth 95.25% and FB1 production 89.58%. Essential oils, ethanol and 70% ethanolextracts of both plants did notsignificantly decrease AFB1 content, whereas aqueous extracts of nettle and M. piperita at the 4000 mg/l concentration decreased AFB1 content 78.15% and 56.1%, respectively. In general, essential oil and extracts of M. piperita were stronger than those from nettlefor reducing AFB1 content and mycelial growth. Aqueous extracts of nettle showed strong AFB1degradation activity andshould be considereda promising new candidate for decreasing AFB1 content.

The use of nano fillers is a good strategy to improve the properties of biopolymer-based packaging films. The present study prepared zein-based nano composite film containing montmorillonite using the solvent casting method. Mechanical, barrier, and thermal properties of the film were investigated. The x-ray diffraction patterns indicated that the composite film has an exfoliated structure. The results showed that the montmorillonite significantly improved the mechanical, barrier, and thermal properties of the zein film. The highest elongation (9.65%) and tensile strength (22.62 MPa) were obtained for the zein nano coposites containing 0 and 10% montmorillonite, respectively. Increasing the montmorillonite content from 0% to 5% decreased the water vapor permeability of the zein film from 1.73 to 1.23 (28%). This parameter significantly increased (1.93) in film containing 10% montmorillonite. The thermal degradation temperature of zein film increased (from 353 to 373 °C) by increasing the montmorillonite content from 0% to 10%. The results revealed that a small amount of montmorillonite can improve the mechanical and barrier properties of zein film, although uniform dispersion of montmorillonite in the zein network is essential to improving the properties of the film.

The present study examined the physical properties, rupture force, and milling characteristics of the common Hashemi, Alikazemi, and Tarom rice varieties in main and ratoon crops. The experiment was conducted as a factorial (3´2) randomized complete block design with five replications. The results revealed that the thickness (1.68 mm) and sphericity of grains (0.388) were less in the main crop thanin the ratoon rice (1.71 mm and 0.398, respectively). The Hashemi variety recorded the greatest length (7.58 mm). Alikazemi recorded the greatest width (2.03 mm), thickness (1.80 mm), geometric mean diameter (3.00 mm), sphericity (0.408), surface area (25.40 mm2), bulk density (561.54kgm-3), true density (1292.24 kgm-3), and thousand grain mass (26.96 g). The highest bending rupture force (24.68 N) and head rice yield (81.36%) was obtained for the ratoon rice crop of the Hashemi variety and the lowest corresponding values (19.6 N and 73.41%, respectively) were recorded for the main rice crop of the Alikazemi variety (P<0.01). There was no significant difference in compressive grain rupture force between varieties or between the main and ratoon crops.

The presents study designed, constructed, and statically calibrated a 6DOF force torque sensor to measure forces and moments acting on a tillage implement. The instrument could measure the three orthogonal forces acting on the implement and the three moments acting around the orthogonal axes up to a maximum force of 5 kN and a maximum moment of 5 kNm. For mechanical design of the 6DOF force torque sensor, the finite element method and Solid Works software were used. The sensing element was constructed from AISI 1045 cold-drawn steel by machining. Strain distributions were analyzed to find the optimal strain node positions in the sensor to minimize cross-sensitivity between horizontal and vertical force measurement. The forces and moments acting on the sensor were measured using strain gauge bridges. A data logger (model DT800; DataTaker) was used for logging and saving data. Calibration of the measurement system was conducted by a calibration system designed for static calibration of a 6DOF force torque sensor. The calibration results showed that the sensor had appropriate precision, sensitivity, and good repeatability for measuring forces and moments. The results showed a high degree of linearity between bridge output voltage and applied force. The interaction of the applied forces and moments was not significant.