• Energy Research
• social sciences close
• 7. Clean energy close
• 13. Climate action close
• 8. Economic growth close
• 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.

Introduction: Identifying the effect of energy consumption, economic growth and foreign trade on CO2 emissions have been studied at both national and international levels. However, there have been very few researches on the effect of financial and banking development on the CO2 emissions, especially in Iran. So, this study aimed to cover this research gap. Methods: This study was a time-series analyses over the period of 1971-2011. In order to investigate about existence of a long-run co-integration relationship between CO2 emissions and banking development indicators in Iran, long-run coefficients were estimated by Autoregressive Distributed Lag (ARDL) and Dynamic Ordinary Least Squares (DOLS) approaches. Moreover, to carry out the econometric tests Microfit (5.0) and Eviews (9.0) software were used. Results: Findings showed that the ratio of domestic credit to private sector by banks to GDP (Banking Development Indicator) reduces CO2 emissions in Iran. In addition, results confirm with theories and other empirical studies showed that energy consumption has positive and significant effect on CO2 emissions in long-run. Conclusion: The government can help to improve environment quality by establishing a strong policy making on credit to firms by banking system. Because in this framework firms to receive credit from banking system are required codified programs to reduce negative outcomes of energy consumption and this lead to a less CO2 emissions in long-run.

Current conventional agricultural systems using intensive energy have to be revitalized through new integrated approaches relying on renewable energy resources, which can allow farmers to stop dependence on fossil resources. The aim of this study was determining the amount of input–output energy used in onion (Allium cepa L.) production in Khorasan Razavi province. For this purpose, the data was collected from 55 onion farm workers in Khorasan Razavi. Inquiries were conducted in face-to-face interviews in April-May 2011. Farm workers were selected based on random sampling method. The results indicated that total energy input was 98479 MJ.ha-1. The share of electricity and nitrogen fertilizer was 50.9 and 14.7%, respectively out of total energy input. The average onion yield under normal conditions was 73227 kg.ha-1 on irrigated farms. The net energy and energy productivity values were estimated to be 18684 MJ.ha-1 and 0.74 kg.MJ-1, respectively, and the ratio of energy output to energy input was found to be 1.19. This indicated an intensive use of input in onion production, which is not parallel to the increase in the final yield. Approximately 77.3% of the total energy input used in onion production was non-renewable (machinery, diesel, fertilizers, chemicals and electricity) and only 22.7% was renewable energy form (human labor, manure, water for irrigation, seeds). Cost analysis revealed that total cost of onion production for one hectare was 79262908 Rials. Benefit–cost ratio was calculated as 1.65. Although energy efficiency of onion production in Khorasan Razavi province is low, it is economically justified.

Background and Objective: Solid waste management has always been one of the major challenges of large cities. Conversion of waste to energy in the form of biogas is known to be an appropriate solution. The aim of this study was to investigate the effect of total solids (TS) content and alkaline pretreatment on biogas production from municipal solid waste (MSW). Materials and Methods: Experiments were done in 1 L glass bottles at 37 °C with different TS contents (5, 10, and 15%), each in 3 replications based on a completely randomized design. Comparison of means was used for interpretations of the result. The volume of the produced biogas, the amount of methane, and changes in pH were measured on a daily basis. In order for better mixing, the digesters were manually shaken for 30 seconds every day. TS, volatile solids (VS), carbon and nitrogen of the feedstock were determined according to APHA standard methods. Results: The highest methane yield and VS reduction was observed in 5% TS. Therefore, this TS was chosen for alkaline pre-treatment. The results showed that pre-treatment with NaOH significantly improved biodegradability of MSW. In 25 days, the production of biogas was 30.38% higher than that of the untreated digester. The highest methane yield was 83.35 mL/g TS and 132 mL/g TS from the control and the pretreated digesters, respectively. Conclusion: The results of the lab experiments showed that the TS of 5 % and the alkaline pre-treatment, significantly improved biodegradability of MSW and consequently increased biogas and methane yield.

Aims: Persons with lower-limb amputations need to achieve more natural gait through more effort, leading to an increase in the energy consumption in them compared to the healthy persons. The aim of this study was to investigate the effects of the socket fit on gait energy consumption level in persons with lower limb amputations. Materials & Methods: In the semi-experimental study, 9 persons with below knee amputation, referred to Tehran Veterans Foundation Center, were studied in 2015. The subjects were selected via available sampling method. The study was consisted of two steps, including improper fit and proper fit conditions. The socket fitting was assessed by the trinity amputation scale and the socket comfort scale. The level of energy consumption of the subjects was measured by the physiological cost index. Data was analyzed by SPSS 19 software using paired T test. Findings: Mean values of persons’ gait speed (p=0.001) and the physiological cost index (p=0.019) with improper fit and proper fit were significantly different. Nevertheless, the difference between gait heart beat and resting heart beat at two steps was not significant (p=0.093). Conclusion: Lower energy consumption can be achieved in persons with lower-limb amputations through the utilization of a proper fit, leading to a better gait.

Global warming and climate change due to increasing greenhouse gases (GHGs) concentration caused widespread concerns in the national and international societies. Carbon dioxide and methane as the most important greenhouse gases in the atmosphere account for more than about 80% of global warming due to greenhouse gases emission. In this study, Multivariate linear regression (method: enter and stepwise) was used to determine the relationship of CO2 and CH4 concentration with NDVI, LST, humidity, and temperature by GOSAT TANSO-FTS level 2 data, MODIS products (MOD13Q1 and MOD11C3), and meteorological parameters (Temperature and Humidity) in Iran. According to the results, the negative correlation among GHGs and NDVI, HUM, and HIG and the positive correlation among these gases and LST and TEM were observed in different seasons of 2013. These correlations showed concentration of carbon dioxide and methane diminished in the study area by increase in humidity, elevation and NDVI and decrease in LST. In spring, important factor in change of CO2 and CH4 was NDVI while, in other seasons climatic parameters were important.