Showing 5 results for Temperature.
Gh. Chegini, B. Ghobadian, M. Barekatin,
Volume 7, Issue 4 (1-2004)
Abstract
The difficulties in the storage of fruit juice and the use of juice powder in various food processing industries has made the juice powder attractive to consumers and producers. Making powder from fruit juice is one of the most complex methods of fruit processing.The hygroscopic nature of fruit juice component and its thermoplastic properties has caused the drying time control and the transportation of the product from the drying zone to the next stage to become very difficult. In this investigation with laboratory spray dryer, the effective parameters on orange juice powder deposit on the wall of the spray dryer was studied. The results indicate that the powder can not be made without the use of additives. Using liquid glucose as an additive to orange juice concentration increased the dryer performance and reduced the wall deposit considerably. With the help of liquid glucose additive, spray dryer optimum conditions were obtained with a feed flow rate of 15 ml/min, inlet air temperature of 130oC and outlet air temperature of 85oC. The results from the statistical analysis of the experimental data show that the parameters of inlet air temperature and feed flow rate have significant effects on the dryer yield and wall deposit both individually and jointly. By increasing inlet air temperature and feed flow rate, the dryer yield decreased but wall deposit increased. In spite of using suitable additives, the wall deposit was still in the range of 14 to 65 %. The results of experiments indicate that the main cause of wall deposit can be attributed to the wall high temperature. It is, therefore, necessary to keep the wall temperature below the orange powder sticky point temperature to prevent rising temperature in wall deposit. For the orange powder containing 2% moisture, the sticky point temperature is 44oC. To control the wall temperature, a dryer with double partition wall chamber and a cooling system is proposed.
M. Basirat,
Volume 12, Issue 45 (10-2008)
Abstract
The pistachio twig borer moth, Kermania pistaciella Amsel (Lep.: Tineidae) is one of the most important pests of pistachio trees (Pistacia vera L.) in Iran. This study was carried out in two pistachio orchards of Rafsanjan area. Periods of pupal cocoon and adult emergence were recorded in two pistachio orchards for four years. Minimum threshold temperatures were calculated according to the least coefficient of variation method for different developmental stages. Cumulative effective temperatures were calculated for different percentages of pupal cocoon and adult emergence. Results showed that minimum threshold temperatures for overwintering larvae to pupal cocoon formation, Larvae to adult and pupal cocoon to adult were calculated 10ْ C, 11ْ C and 12ْ C, respectively. Cumulative effective temperatures for occurrence of 50% pupal cocoon from overwintering larvae with minimum threshold temperatures 10ْ C under field conditions were 73.6 degree-day. Cumulative effective temperatures for occurrence of 65% adult emergence from overwintering larvae with minimum threshold temperature of 11ْ C under field conditions were 213.8 degree-day. Cumulative effective temperature for occurrence of 65% adult emergence from 5% pupal cocoon, 50% pupal cocoon and 5% adult emergence with minimum threshold temperature of 12 ْ C were 145.3, 126.9 and 71.6 degree days, respectively.
N. Abbasi, A. A. Afsharian,
Volume 22, Issue 1 (6-2018)
Abstract
Gypsiferous soils are one of the problematic soils which, due to solubility and contact with water, are a threat to various civil structures, especially water structures. Various factors affect the rate and amount of gypsum particles solubility. Gypsum types, the soil texture, the amount of gypsum in soil, the hydraulic gradient, and temperature and flowing water from gypsum soil are the major factors affecting the quality and quantity of the gypsum solution. In this research, the effects of some peripheral conditions including water temperature and hydraulic gradient on the solubility of gypsum soils were studied. To this aim, samples of gypsum soils were provided artificially by adding various rates of the natural gypsum rock including 0, 5, 10, 20 and 30 percent by weight of clay soil. Then, all gypsum soils were leached under five hydraulic gradients levels including 0.5, 1, 2, 5 and 10. The results indicated that the rate of Gypsum in the soil had a direct effect on the rate of solution in a way that by increasing the percent of Gypsum, the rate of solubility was increased. Also, the rate of leaching (the rate of the derived Gypsum from soil to the primary rate of Gypsum) was decreased by increasing the rate of Gypsum. In addition, by increasing hydraulic gradient, the speed of water and its amount in soil environment within a specified time were raised; further the rate of gypsum was increased too. Also, it was found that the rate of the solubility was increased directly by the temperature. The solubility rate of the gypsum soil at 50 C0 was found to be 2.5 and 1.6 times greater than that of the soil at 5 and 20 C0, respectively.
Sh. Zand-Parsa, S. Parvizi, A. R. Sepaskhah, A. A. Kamgar Haghighi,
Volume 22, Issue 1 (6-2018)
Abstract
In this study, the values of moisture and soil temperature were estimated at different depths and times under unsteady conditions by solving the Richards’ equation in an explicit finite difference method provided in Visual Studio C#. For the estimation of soil hydraulic parameters, including av and nv (coefficients of van Genuchten’s equation) and Ks (saturated hydraulic conductivity), soil moisture and temperature at different depths were measured by TDR probes and the stability apparatus, respectively. The objective function [equal to Root Mean Square Error (RMSE)] was minimized by the optimization of a parameter separately, using the Newton-Raphson method, while, the other parameters were considered as the constant values. Then, by replacing the optimized value of this parameter, the same was done for other parameters. The procedure of optimization was iterated until reaching minor changes to the objective function. The results showed that soil hydraulic parameters (coefficients of van Genuchten’s equation) could be optimized by using the SWCT (Soil Water Content and Temperature) model with measuring the soil water content at different depths and meteorological parameters including the minimum and maximum temperature,, air vapor pressure, rainfall and solar radiation. Finally, the measured values of soil moisture and temperature were compared to the depth of 70cm in spring, summer, and autumn of 2015. The values of the normalized RMSE of soil water content were 0.090, 0.096 and 0.056 at the soil depths of 5, 35 and 70 cm, respectively, while the values of the normalized RSME of soil temperatures were 2.000, 1.175 and 1.5 oC at these depths, respectively. In this research, the values of soil hydraulic parameters were compared with other previous models in a wider range of soil moisture varying from saturation to air dry condition, as more preferred in soil researches.
A. H. Nasrollahi, H. Ahmadi, Y. Sabzevari, S. Nouri,
Volume 24, Issue 2 (7-2020)
Abstract
The Plant Water Resistance Index (CWSI) is a tool that can be used for the rapid monitoring of plant water status, which is a key requirement for the accurate product irrigation management.The purpose of this study was to calculate the CWSI index for bean hares in the Khorramabad region for two methods of surface irrigation and drip tape irrigation. For this purpose, a design was implemented in the form of randomized complete block design and split plot experiment. The main factors included drip tape irrigation (T) and surface irrigation (F), and the cultivars of Chibi cultivars including COS16 (C), Sadri (S) and diluted (K) served as sub-plots. By using the field measurements, the position of the upper and lower base lines was estimated for each treatment in different months and used to calculate the CWSI index. The results showed that CWSI values calculated in the surface irrigation during plant growth period were always higher than those in the drip tape irrigation. The highest value of CWSI index was obtained for the Sadri variety, which was equal to 0.20 and 0.26, for the type and surface method, respectively. Statistical analysis showed that the effect of irrigation method on the amount of water stress index was significant at 5% level, but there was no significant difference between different cultivars. According to the results of this study, the threshold values for CWSI were considered to be 0.19 and 0.24 for surface and drip tape irrigation respectively, and relationships were presented based on the differences in vegetation and air temperature to determine the irrigation time.
