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Showing 4 results for Time.

N. Mehrdad, M. Alikhani, G. R. Ghorbani,
Volume 8, Issue 2 (7-2004)
Abstract

In a completely randomized design with a factorial arrangement (3× 5× 3), three fistulated sheep with an average body weight of 47.5 ± 2.5 kg were used to determine the effect of cutting and growing stages (no bloom , early bloom and full bloom) on chemical composition and In situ degradability of alfalfa (Medicago sativa). Nylon bags (50 µm pore size) were filled with 3.5 g of each sample and suspended in the rumen before morning feeding and incubated for seven different times (0, 2, 4, 8, 16, 24 and 48 h). The results showed that alfalfa at no bloom stage had the highest crude protein and the lowest crude fiber content. The third – cut alfalfa had the highest degradability of dry matter and organic matter. Extent of degradability depended on crude fiber and solubility. During growth stage, the protein, soluble material and degradability levels decreased while crude fiber, neutral detergent insoluble crude protein (NDICP), and acid detergent insoluble crude protein (ADICP) increased. The amount of ADICP was an estimate of unavailable crude protein in the rumen. Although the rate of organic matter degradation was maximum in full bloom, no significant difference was observed between the three stages of growth. Effective degradability (ED) of crude protein was significantly different among stages the growth (p<0.05). Effective dry matter degradability (EDDM) with a passage rate of 6%/h was significantly higher in the third cutting of alfalfa. The results of this study showed that first cutting and full bloom alfalfa had the lowest and fifth cutting and no bloom had the highest CP levels. The effect of cutting and growing stages on degradability parameters was variable and did not allow any firm conclusions to be made.
M. Ghanbari , M. Shahedi,
Volume 12, Issue 43 (4-2008)
Abstract

Baking is obviously one of the most important stages of bread production. Baking time and oven temperature have greatest effects on bread quality. The aim of this study was to investigate the effect of baking time and temperature on bread quality and its shelf life. In this study, the effect of three rates of oven temperature (top and under bread surface) and baking time levels on bread quality and its shelf life was investigated. Baking temperature and time were 300 and 280 °C for 3 minutes and 20 seconds, 300 and 350 °C for 2 minutes and 30 seconds and 350 and 380 °C for 2 minutes respectively. Soluble starch and staling factors of the samples were measured. The data was statistically analyzed by complete randomized design and comparison was made between the means via Duncan,s multiple range test at 5% level. The results showed that the bread baked in various time–temperature conditions were different in moisture content. The bread baked at lower temperature and longer time had the lowest moisture. Also, the result showed that the amount of soluble starch increased by increasing the baking time and decreasing the baking temperature. The bread baked in various baking conditions showed significant differences in staling rates. Lower baking time and higher baking temperature caused the lowest bread staling rates.
S. S. Okhravi, S. S. Eslamian, N. Fathianpour, M. Heidarpour,
Volume 19, Issue 74 (1-2016)
Abstract

In addition to kinematic description of biological reaction, flow pattern plays an important role in designing constructed wetlands. This study investigates the effects of flow distribution on constructed sub-surface horizontal flow wetland with a length of 26 m, width of 4 m and 1% bed slope in order to understand internal hydraulic functioning patterns. Inlet configuration is selected as a variable parameter. Three different cases of inlet and outlet configurations were 1) midpoint, 2) corner, and 3) uniform. Outlet has been fixed in all configurations. Uranine tracer was used to determine the influences of flow distribution by drawing hydraulic retention time curve in different cases. Results showed that mean residence times for each configuration were equal to 4.53, 3.24 and 4.65 days, respectively.  Retention time distribution curve provided conditions, not only for showing dispersion patterns throughout system but also for interpreting hydraulic parameters like hydraulic efficiency and effective volume. According to the retention time curve, effective volume was 87.5% in configurations 1 and 3, and 62.1% in configuration 2 following numerous short-circuiting ratios. Finally, the best configuration of inlet-outlet layout to improve the performance of effluent treatment and use the geometry effectively was found to be the uniform-midpoint based on physical experiments followed by midpoint–midpoint as the second best.


Amir Mahdi Bayat, Mohammad Shayannejad, Mahmood Akbari,
Volume 30, Issue 1 (3-2026)
Abstract

Mathematical models are a suitable tool for surface irrigation design. The EDOSIM model, as a surface irrigation simulation-optimization model, utilizes simulation with the volume balance model and meta-heuristic optimization. In this study, with the aim of improving the simulation of the advanced phase in the EDOSIM model, the Full Hydrodynamic model was replaced by the Volume Balance model for furrow irrigation design, leading to the development of the EDOSIM-HD model. The Saint-Venant equations were discretized using the implicit Preissmann’s finite difference scheme and transformed into a set of nonlinear equations in the form of a system of equations. The resulting system of equations was linearized using the Newton-Raphson method and solved using the Sparse matrix method. The results were compared with the SIRMOD software to validate the simulation. Using the particleswarm solver of the MATLAB software optimization toolbox, the inflow rate as a decision variable was used to optimize the hydraulic objective function consisting of efficiency, adequacy, and uniformity. The results in the experimental field showed that in the initial simulation with an inflow rate of 1.4 lps, important irrigation times, infiltration volume, performance indicators, profiles, and hydrographs showed a deep percolation loss of about 50 percent of water. Also, the results of the EDOSIM-HD model were closer to the Hydrodynamic model of the SIRMOD software than the EDOSIM model. By optimizing and increasing the optimal flow rate (1.8 lps) compared to the initial inflow rate, the advance, cut-off, depletion, and recession times were reduced, and the required infiltration time remained unchanged. The reduction in infiltration volume was also achieved by applying higher inflow rates in less time. All performance indicators also moved closer to their optimal state. Except for Tail Water Ration (TWR), which showed a slight increase of 11 percent (due to higher inflow rate), was negligible compared to the sharp 22% reduction in Depth Percolation Ratio (DPR), and 10% increase in Application Efficiency (Ea). Totally, according to the performance indicators obtained in the validation with the SIRMOD, the simulation of the EDOSIM-HD model was better than in the EDOSIM model in the advanced phase of furrow irrigation design


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