• Energy Research
• Persian close

Background and Objective: In recent years, management and disposal of municipal solid waste has become a global problem and the most important environmental concern. Anaerobic digestion is a cost-effective solution for treatment of both solid waste and wastewater. The aim of this study was to investigate the positive or negative effects of calcium chloride content in anaerobic digestion process of municipal solid waste and leachate on biogas production. Materials and Methods: Experiments with 8 levels of calcium chloride on co-digestion of municipal solid waste and leachate were investigated in 500 ml digesters under mesophilic conditions in a completely randomized design with three replications. Reactors with a ratio of substrate to inoculum of 2 (on VS basis) were operated and the volume of the biogas was measured daily. Volatile and total solids, carbon/nitrogen of waste, COD, BOD and heavy metals were measured by following APHA. Results: The results of the experiment showed that the pH was decreased with increasing calcium chloride concentration. The highest amount of cumulative biogas production was obtained in CaCl2 of 2 g/L with the highest VS and TS reduction. Higher concentrations of CaCl2 (≥3 g/L) caused a reduction in the degradability of volatile and total solids and, as a result, a decreased performance of the digester. Conclusion: The results clearly confirmed that the addition of calcium chloride was an effective solution to improve biodegradability in co-digestion of the MSW and leachate and consequently to reduce the total and volatile solids and to increase the amount of‌ biogas.

Background and objective: Alcoholic drinks are interested in societies since long time ago. Other than its psychological effects in drinkers, several researches have been done about ethanol side-effects. In this study, we investigate different aspects of ethanol consumption by oral intake. Results: Ethanol interferes in active transport of nutrients on the brush border. With regard to macronutrients, it disturbs the normal hydrolysis in the intestine. Although, lower absorption of macronutrients in the small intestine is compensated by their increased absorption in the lower gastrointestinal tract. It has been reported that ethanol intake at lower doses may protect the heart, but its prolonged intake could damage surface of villi, make lesions in the intestine, induce diarrhea, and stimulate growth of intestinal pathogens (known as endotoxemia). Chronic alcohol consumption induces inflammation and oxidative stress in drinkers, which affect the liver as the main metabolizing organ followed by brain. Reduced supply of antioxidants in drinkers and increased inflammation after alcohol intake makes the body susceptible to further infections. Conclusion: Despite the positive effect of ethanol in prevention of cardiovascular diseases at low doses, its negative impacts on the other organs are not deniable. Importantly, no sale level has been introduced for ethanol oral intake. Therefore, the scientists recommend to avoid its drinking every time.

Globalization is a driving force in emitting carbon dioxide (CO2), which causes countries to interact with each other economically, socially and politically. The interaction between countries will inevitably affect CO2 emissions. The aim of this study is to investigate the dynamic effects of globalization and energy consumption on environmental degradation in Iran. Therefore, it examines which variable (globalization, energy consumption or economic growth) is more effective in the process of environmental degradation. The Fully Modified Least Squares (FMOLS) and Charnes, Cooper and Rhodes (CCR) models are applied to investigate the subject over the period 1978-2016. In addition, Maki co-integration test is used to check the long-term dynamic relationships. The results show that globalization increases environmental degradation regardless of the decrease or increase in economic growth. This indicates that the scale effect of is dominant in Iran.

This study investigates the Granger causality relationship between energy consumption, carbon emission and industrial value added, including labor and gross fixed capital formation in the model. We found that energy consumption is Granger cause of carbon dioxide emission and industrial value added. Also results of variance analysis model suggests that the long term effects of variables on their own swings gradually declines, and share of other variables increases.

Abstract Solar radiation is an essential factor in irrigation scheduling, hydrological cycle, crop growth simulation models and estimation of reference evapotranspiration. The aim of the present research was to investigate the accuracy of solar radiation estimation models and their effects on reference evapotranspiration. For this purpose, the meteorological data of 4 synoptic stations including Urmia, Takab, Salmas and Mahabad in West of Urmia lake catchment in daily scale were used. Solar radiation was estimated using seven models including, Hargreaves-Samani, Allen, Self-Calibrating, Samani, Annandale, Bristow-Campbell and Angstrom–Prescott. Then, the obtained values were used in FAO- Penman-Monteith equation to estimate the reference evapotranspiration. In order to evaluate the models' accuracy, the statistical indicators including root mean square error, mean bias error and determination coefficient were used. The evaluation results of the models showed that the Angstrom – Prescott model had the best performance, and the Samani method was the weakest method in the studied stations. The average values of the root mean square error for the Angstrom–Prescott and Samani methods in the studied region were obtained 0.48 and 1.43 mm/day, respectively.

Aluminum-lithium alloys are among the ultra-lightweight and workable alloys that have replaced some air alloys (such as 2000 and 7000 groups) due to their higher elastic modulus and lower specific gravity. Increasing the mechanical properties of these alloys using various thermal-mechanical methods (Thermo Mechanical) has always been considered by researchers. Creating GP regions through low temperature aging processes has a great impact on the physical and mechanical properties of aluminum-lithium alloys. In this research, in the first part of the experiments, by performing natural aging and artificial aging at a temperature of 100 اد C, the formation and impact of these areas on the properties of the alloy were investigated. In the second part of the experiments, the precipitation of phase T1 during the aging process and the effective effect on the optimal time of the aging process at temperatures C150 and C190 for a sample of aluminum-copper-copper-lithium alloy sheet have been investigated. The results show that the formation of GP areas in the structure increases the hardness, strength and special strength of the alloy and by performing the aging process at higher temperatures and forming stable sediments, the process of increasing the hardness and strength continues while the special strength of the alloy decreases. It was found that the change in energy level in the range C250 to C300 is related to the deposition of phase T1 and the change in energy level in the temperature range C450 to C305 due to its dissolution in the alloy structure. The energy of the formation and dissolution activations of phase T1 in this study was calculated to be (kj / mol) 1/122 and (/ mol (kj3 / 130), respectively, which is equal to the activation energy of the penetration of the constituent elements of this phase (copper and lithium) in the network structure. It is aluminum.

AbstractIntroduction and objectives: As a result of global warming, the climate will change in terms of average temperature and rainfall, with groundwater being one of the factors impacted. Consequently, the influence of climatic elements such as temperature and precipitation on groundwater drought values in the Talesh plain was investigated.Materials and Methods: Initially, the LARS-WG model was used to calculate climate change values. Subsequently, using the Mann-Kendall test and the Pearson correlation of these two indices, the values of meteorological and groundwater drought indices were produced, as well as a study of the trend of these indices.Findings and discussion: The findings of the annual changes in rainfall and temperature throughout the following period (2020–2040) reveal that precipitation of 9, 1.75, and 0.75% and the temperature of those have grown by 1.05, 1.32, and 1.81 °C under the scenarios of RCP2.6, RCP4.5, and RCP8.5, respectively. Also, in the basic period, the declined average level of the aquifer in this 15-year period was 0.86 m. On the other hand, the impacts of climate change on decreasing groundwater level over the future period compared to the base period under the above scenarios indicated that the aquifer by 2.07, 2.21, and 2.34 m, respectively. Although it indicates that the rainfall has risen in the area, unrestricted drain from the aquifer has resulted in a decline in groundwater. The study also reveals that meteorological drought occurred in the basic era at a rate of 49.66, 50.35, and 41.73% at the scales of 12, 24, and 48 months, respectively. Therefore, in order to mitigate the severity of the drought and avoid excessive groundwater aquifer fall in this plain, required actions are essential to decrease water consumption by water resources managers and executive bodies under the present circumstances.

Energy consumption in the world is increasing for economic growth, and as a result of the emission of greenhouse gases, especially carbon dioxide, which has destructive environmental effects, the consumption of fossil fuels has an increasing trend. Present study tries to find the effect of renewable and non-renewable energy consumption on air pollution with respect to the moderating role of economic growth, utilizing the data of time series from 1990 to 2017 in Iran and with the generalized method of moments and in terms of some control variables such as energy efficiency coefficient and urbanization, the hypotheses were tested. Findings indicate that, the effect of renewable energy consumption in reducing carbon dioxide emissions (negative coefficient at a significant level of 10%) and the effect of non-renewable energy consumption in increasing carbon dioxide emissions (positive coefficient at a significant level of 5%). Also, the role of economic growth as a moderating variable on the relationship between renewable energy consumption and carbon dioxide emissions is positive and on the relationship between non-renewable energy consumption and carbon dioxide emissions is negative and significant. Developing investment and increasing the share of the renewable energy sector in the country along with improving energy efficiency and technology level can be effective in reducing air pollution.

The main objective of this study is to design and construct the new, spouted bed dryer, for food drying sensitive foods specially. For this purpose, firstly a new design of dryer was planned to achieve the maximum efficiency and flexibility for liquids and solids drying. After constructing and initial setup of spouted bed, basic experiments such as investigation of an inert particles motion, pressure drop, energy consumption were conducted and optimal system requirements for two particle size (5.8 & 7.8 mm) were determined. The results indicated that changes in pressure drop in the dryer chamber containing inert particles are followed from the Ergun equation. Energy consumption in this system is variable in the range of 3-8 kW per hour. Also results reveals that the energy consumption of the new design of spouted bed dryer is less than the spray dryer for liquid foods drying.

Today’s world faces two major crises including environmental pollution due to fossil fuels and the reduction of these fuels, so energy supply through renewable energies has been considered a sustainable solution. The purpose of this study was to assess factors affecting the tendency to use biofuels among villagers. Heads of households in rural areas in Chavarzagh district, Tarom township, Zanjan province formed the statistical population of the study (N=2742). The sample size was estimated using the Cochrane formula (n=161) and samples were selected using multi-stage cluster sampling method. The descriptive and correlational research method was used in this study. The validity of the questionnaire was approved by a panel of related faculty members. Cronbach's alpha coefficient was used to confirm the reliability of the questionnaire (0.70-0.83). Data was analyzed using SPSS 21. Regression analysis showed that risk, attitudes towards biofuels, self-efficacy, training, eliminating subsidies for fossil fuels and encouraging the use of biofuels, increasing public awareness about the benefits of biofuels and perceived barriers explained 40.6 percent of the variation of villagers’ tendency to use biofuels.