Introduction: Carrot juice is one of the most consumed and healthy fruit juices and is a rich source of carotenoids, such as beta-carotene, which is responsible for its orange color and is a precursor of vitamin A (Zhou et al., 2009). In conventional methods of food heating, due to the transfer of heat by the conduction method and the presence of a hot surface in contact with the food, particles near the surface are exposed to heat more than distant particles; therefore, food compounds are damaged and there is a possibility of burning of surface part of the food (Kamali and Farahnak 2015). Ohmic heating is a thermal process that produces heat by passing an alternating current through the food. This heating system differs from conventional heating methods in terms of heat generation and heat transfer, as well as in terms of temperature distribution that occurs during heating. Studies show that this method has a very high thermal uniformity, environmentally friendly, high efficiency and easy control over other common thermal techniques. Ohmic heating is also used as a method to inactivate microbial activity (such as pasteurization), extraction, dehydration or solid to liquid transformation (Pereira et al., 2007). Many agricultural products spoil very quickly due to high humidity, which makes them particularly difficult to store. In addition, due to the seasonality of these products and on the other hand the demand for its consumption in other seasons, the need to processing of these products (such as drying and concentrating of its extract) seems necessary (Darvishi et al., 2013). The amount of heat generated by ohmic heating directly depends on the electrical resistance of the food and the Voltage gradient applied (Marcos et al., 2010). Ohmic heating derives its name from Ohm's law, which is the known relationship between current, Voltage and electrical resistance. In ohmic heating, the food placed between the electrodes acts as a resistor in the electrical circuit. This food must be physically able to conduct electricity (Sakr and Liu 2014). The purpose of this study was to investigate the quality characteristics of carrot juice such as color changes, pH and specific energy consumption. Materials and methods: Carrot samples used in this study were prepared from the city of Khorramabad in 2018. After washing the fruits with water, the surface water of the fruits was taken with absorbent paper. An industrial juicer extracted the juices. It should be noted that no filtration was performed on the extracted fruit juices because the heating rate of a substance in the ohmic heating method is strongly dependent on the particle size of the substance. The presence of pulp increases the heating rate and thus increases the final quality of the product (Shiby et al., 2014). In addition, fruit pulp has a very high percentage of vitamins and minerals. The amount of fruit pulp was about 12% by weight. The initial humidity of carrot was calculated using AOAC (2002) standard of oven heating (24 hours heating at 103° C) equal to 89. 7%. In all experiments, the weight of the carrot juice sample was considered constant and equal to 100 g. Ohmic heating system used include temperature sensor, digital scale, power analyzer, Voltage variable (Voltage regulator-to select the required Voltage), ohmic cell (ohmic container) and computer. The ohmic container is a rectangular cubic tank made of glass with a thickness of 4 mm and a height of 18 cm in the form of a piece. Two electrodes (made of stainless steel, aluminum, zinc and copper) with dimensions of 10 × 11 cm (electrode surface) and with a thickness of 1 mm are connected vertically to the inner walls of the chamber with steel screws to the inner body of the ohmic container. The distance between the electrodes is 9. 5 cm. Heating tests were performed at Voltage gradient levels of 15, 20 and 25 V/cm until the weight of the material reached 60 g (40% concentration) and the variable Voltage was switched off. Prior to testing, the samples were placed in the laboratory for 10 minutes to be at the same temperature as the environment. After heating, the parameters of temperature, weight, electric current and Voltage passing through the food material were measured and recorded. A digital power analyzer was used to measure changes in Voltage, current and energy consumption during the heating process. In order to make changes in the input Voltage to the ohmic heating system, a number of Voltage variable devices with a working range of 0 to 330 volts were used. The pH of carrot juice samples before and after ohmic heating was measured and recorded by a pH meter. It is noteworthy that the pH of the heated samples was measured after isothermal exposure to the Environment. Lab color space was used to obtain the color of the product and also to compare the product obtained from different treatments with each other. Photoshop software was used for this purpose. In this study, the effect of changing the Voltage gradient and the type of electrode material on the quality characteristics of carrot juice was studied by performing a basic test in a completely randomized design with three replications. Independent variables include Voltage gradient (15, 20 and 25 V/cm) and type of electrodes (steel, copper, zinc and aluminum) and dependent variables include product quality characteristics before and after the ohmic heating process including color changes, pH and special energy consumption. Data analysis of variance was performed using SPSS 16 software. Results and discussion: The results showed that the interaction of electrode material and Voltage gradient on the total color change (Δ E) of carrot juice was significant (P<0. 05) and the best performance (lowest Δ E index) was related to the use of copper and steel electrodes and Voltage gradient of 25 V/cm. The interaction of electrode material and Voltage gradient on the specific energy consumption of carrot juice was significant (P<0. 05). The results also showed that the interaction of electrode material and Voltage gradient on the percentage of pH changes in carrot juice was significant and the lowest percentage changes in pH of carrot juice were related to steel and copper electrodes in the Voltage gradient of 25 V/cm, respectively. As the Voltage gradient increased, the specific energy consumption decreased. Specific energy consumption was changed from 3. 45 to 3. 87 MJ/kg for copper electrode in Voltage gradient of 25 V/cm and steel electrode in Voltage gradient of 15 V/cm, respectively. Conclusion: The interaction of electrode material and Voltage gradient on the percentage of pH changes, total color change (Δ E) and specific energy consumption of carrot juice was significant. In this research, the best performance of the ohmic heating system with the least energy consumption, the least changes and the least changes were related to the copper electrode and Voltage gradient of 25 V/cm.

Electrokinetic removal of heavy metals from the contaminated soils seems an innovative approach for their remediation. This technique may require much less time for the removal particularly in the soil with lower permeability comparing to the conventional leaching methods. In the current study electrokinetic remediation of a calcareous soil contaminated by three heavy metals (Zn=1400 mg kg-1, Cd=15 mg kg-1 and Pb=250 mg kg-1) due to the release of sludge' s from mining industry around Zanjan city north west of Iran, was investigated in disturbed soil columns. Treatments imposed during the experiment were three moisture contents (saturated, FC and 0.7 FC), and two Voltage gradients (1.3 and 2.66 volts per cm of the column length). Effects of three electrolytes (distilled water, Acetic acid, EDTA), electrolyte circulation and anodes displacement on the removal efficiency were also studied. Experimental data showed that raising Voltage gradient and water content both enhanced ion migration through the column and thus led to considerably grater removal. After 10 days imposing the above Voltage gradient under saturation condition, the removal of Cd, Zn and Pb achieved to 32.6%, 31.3% and 18.9%, respectively. Reducing water content to 0.7 FC reduced the removal percents to 21%, 18.4% and 12.3%, respectively.The largest removal belonged to Cd; with Zn and Pb being the second and third in this respect.

Objective: To examine the efficiency of both the Zeta and density gradient centrifugation (DGC) methods for the selection of normal chromatin sperm by TUNEL, sperm chromatin dispersion (SCD), acridine orange and chromomycin A3 (CMA3).Materials and Methods: The study was performed on 63 patients. Semen analysis was carried out according to WHO criteria. Semen samples were divided into three equal portions. One portion was used as the control, the second portion was used for the Zeta method and the third portion underwent DGC method. All portions were evaluated for sperm morphology (Diff Quick staining), protamine deficiency (CMA3) and DNA integrity (SCD, AO and TUNEL). Coefficients of correlation and student’s t test were carried out using SPSS 11.5.Results: The mean percentage of abnormal sperm, protamine deficiency and DNA fragmentation in the Zeta and DGC methods were significantly decreased as compared to the control group (p<0.005). In addition, the DGC method was higher in comparison to the Zeta method in the selection of sperm with normal morphology (p<0.005). The Zeta method was higher in comparison to the DGC method in the selection of sperm with intact DNA (p<0.005).Conclusion: Both Zeta and DGC methods were effective in the selection of sperm with better quality in terms of normal morphology, normal protamine content and DNA integrity. Therefore, we suggested that the combined Zeta and DGC method should be used for selection of normal sperm.

Introduction: Thermal processing has a huge impact on the textural attribute of the final food product and texture is a major factor contributing the overall quality of food. Ohmic heating is an advanced thermal processing method in which heat is internally generated within foods by passing an alternating electric current through them. Ohmic heating can volumetrically heat the entire mass of a food system, resulting in faster heating, better quality and less energy consumption than conventional thermal processing. gradient Voltage and electrode type have high effect on ohmic heating system. …

Abstract: Establishment of gradient layer is the most important step in the filling of a solar pond. While saline diffusion that occurs naturally in a solar lake sets up the gradient layer automatically, stacking and salinity redistribution methods are applied in man-made solar ponds, practically. In this paper advantages and disadvantages of each method are discussed and author's experiences in the filling of two solar ponds are presented The theory of step by step raising of diffuser in redistribution technique is elaborated and a criterion for diffuser discharge is evaluated.

Severe Voltage fluctuations at different points of the network are the main concerns of the widespread low-Voltage electrical energy distribution networks. In particular, small industrial loads and rural consumers in remote geographical areas, which are fed by long lines, always experience great Voltage drops. The use of common distribution transformers equipped with off-load tap changers has not been effective in solving this problem due to issues such as lack of access to all network points for operators, the need to de-energize the line during tap change, and the successive and unpredictable load changes. Therefore, the use of transformers with automatic Voltage adjustment at different points of distribution networks has attracted much attention. The present research aimed to implement a simple solid-state Voltage regulator (SSVR) in the low power range to automatically eliminate severe Voltage fluctuations. In this research, a solid-state Voltage regulator with a rated power of 5 KVA was designed and built to automatically compensate for the Voltage of a small group of home customers (who have a severe Voltage drop due to the distance from the distribution post). The results of the measurements showed that this equipment can limit the Voltage changes to 220±3%, while it does not affect the power quality. In addition, various hardware and software protections were designed for the device built against network disturbances and abnormal consumer functions.

Voltage stability may be improved by various control functions. In this paper, it is shown that how High Side Voltage Control (HIVC) may be employed for this purpose. Two test systems, namely a 22- bus and IEEE U8-bus systems are used to demonstrate the proposed tuning strategy for HSVC control parameters.

There are fewer problems encountered with optical Voltage transducers in comparison with their inductive and capacitive counterparts. Although capacitive and inductive transformers are used vastly for the purpose of measurement and protection in the networks, they cause problems such as core saturation and improper transient responses which decrease the accuracy of measurement and efficiency of the protection schemes. As a result, optical Voltage transducers are considered as proper candidates for replacing the conventional inductive and capacitive transformers. Lighter weight, smaller size, larger dynamic range, wider bandwidth, insensitivity to electromagnetic interference, stability over temperature change, absence of iron core saturation, low maintenance and replacement cost, etc. are some of the advantages of optical Voltage transducers over inductive and capacitive transformers. In this paper, the Modified Adaptive Method is introduced in order to measure the integral of electric field with minimum number of sensors. Using this algorithm makes the effects of other fields minimum. One more advantage of this method is the possibility of improving the accuracy of the measurement by using a correction factor. The correction factor is determined by considering the level of accuracy, environmental conditions and the number of sensors. Simulation results show the great validity and effectiveness of this method over a wide range of variations.