• Energy Research
• 6. Clean water close
• Persian close

Introduction: The latest report of the Intergovernmental Panel on Climate Change (IPCC) states that future emissions of greenhouse gases (GHGs) will continue to increase and cause climatic change (16). These conditions are also true for Iran. The three greenhouse gases associated with agriculture are carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). The three GHGs associated with agriculture CO2, CH4, and N2O differ in their effectiveness in trapping heat and in their turnover rates in the atmosphere. This environmental change will have serious impacts on different growth and development processes of crops. Increasing temperature could affect physiological processes such as photosynthesis, respiration and partitioning of photoassimilates. Farmers are not able to change or manage the climatic conditions, but some factors such as soil, water, seed and agricultural practices can be managed to reduce the adverse impacts of climate change (32). Mitigation and adaptation are two known ways for reducing the negative impacts of climate change. Mitigation strategies are associated with decreasing greenhouse gas (GHG) emissions through management practices such as reducing chemical fertilizer application, mechanization, increasing carbon storage in agroecosystems, planting biofuel crops and moving towards organic farming (42), etc. Material and Methods: This study was carried out at the experimental field of the Ferdowsi University of Mashhad in 2011 and was repeated in 2012. The Research Station (36°16´N, 59°36´E) is located at about 985 m a.s.l. Average temperature and precipitation rate of the research station in two years are shown in Figure. 1. The three-factor experiment was set up in a strip-split-plot arranged in a randomized complete block design with three replications. The experimental treatments were tillage systems (conventional and reduced tillage) and residual management (remaining and leaving of maize residual) assigned to main plots and different levels of N fertilizer (0, 150, 300 and 450 kg urea ha-1) was randomized as a subplot in tillage treatment. The seedbed preparation was made based on common practices at the location. Plot size under the trial was 4 m × 3 m so as to get 70 cm inter row spacing. Maize seeds (single-cross 704 cultivar) were hand sown in May for two years. The ideal density of the crops was considered as spacing 20 cm inter plant. As soon as the seeds were sown, irrigation continued every 10 days. No herbicides or chemical fertilizers were applied during the course of the trials and weeding was done manually when necessary. Measurement of CO2 emissions was performed by the closed chamber method. For this purpose, PVC plastic rings (20 cm in diameter and 30 cm height) were scattered on each of the plots. The chambers were placed in soil for two hours and the gathered air was collected by 10 ml vacuum syringe. Then, the samples were transferred to the laboratory and CO2 was measured using GC-mass. Results and Discussion: The results showed that CO2 emissions for conventional tillage was about 15 and 10% higher than the reduced tillage in 2011 and 2012, respectively. The CO2 emissions can be taken as indicators of soil tillage effects on the soil ecosystem, because CO2 emissions are closely connected to the microbial turnover and the physical accessibility of organic matter to microbes. These parameters were more available in the conventional tillage than the reduced tillage. CO2 emissions were strongly higher in the remaining residual condition rather than leaving condition in two years. CO2 emissions in the remaining residual condition was about 4.36 and 5.37 times higher than that of the leaving residual condition in 2011 and 2012, respectively. The microbial respiration and humidity of soil in the remaining residual condition is higher than that of the leaving residual condition. CO2 emission was elevated with increasing the rate of N fertilizer. The N fertilizer can increase the microbial activity of the soil. Cover cropping and N fertilization can increase CO2 emissions in full and reduced tilled soils by increasing the amount of crop residue returned to the soil. The results showed that CO2 emissions in 2011 were higher than 2012 in all treatments. The residual treatment had more effect on daily CO2 emission in comparison with tillage and N fertilizer treatments in both years. The trait was higher under conventional tillage, residue remaining and higher N fertilizer levels compared to reduced tillage, residue leaving and lower N fertilizer application. Linear regression for air temperature and mean CO2 emission illustrated that there was a positive correlation between air temperature and CO2 emission. Conclusion: In essence, the results showed that CO2 emissions for conventional tillage were higher than that of reduced tillage in two years. Remaining residual condition had strongly higher CO2 emission rather than leaving condition. CO2 emission was elevated with increasing the rate of N fertilizer.

Introduction: The increasing Greenhouse Gases in atmosphere is the main cause of climate and ecosystems changes. The most important greenhouse gas is CO2 that causes global warming or the greenhouse effect. One of the known solutions that reduces atmospheric carbon and helps to improve the situation, is carbon sequestration in vegetation cover and soil. Carbon sequestration refers to the change in atmospheric CO2 into organic carbon compounds by plants and capture it for a certain time . However, the ecosystems with different vegetation have Impressive Influence on soil carbon sequestration (SCS). Soil as the main component of these ecosystems is a world-wide indicator which has been known to play an important role in global balance of carbon sequestration. Furthermore, carbon sequestration can be a standard world trade and becomes guaranteed. Costs of transfer of CO2 (carbon transfer From the atmosphere into the soil) based on the negative effects of increased CO2 on Weather is always increasing, This issue can be faced by developing countries to create a new industry, especially when conservation and restoration of rangeland to follow. This research was regarded due to estimation of SCS in three land use types (orchard, paddy rice and forest) in a Part of Ramsar Lands, Northern Iran. Materials and Methods: Ramsar city with an area of about 729/7 km2 is located in the western part of Mazandaran province. Its height above sea level is 20 meters. Ramsar city is situated in a temperate and humid climate. Land area covered by forest, orchard and paddy rice. After field inspection of the area, detailed topographic maps of the specified zone on the study were also tested. In each of the three land types, 500 hectares in the every growing and totally 1,500 hectares as study area were selected .For evaluation the sequestration of carbon in different vegetation systems,15 soil profile selected and sampling from depth of 0 to 100 centimetres of each profile was done by collecting 15 samples with the total number of 45 samples. Soil sampling (at the 0-100 cm depth) was carried out following determination of points on map. Some of soil features (i.e., Soil structure, Bulk density ,Texture, Acidity, CEC, total Nitrogen and Organic Carbon) were measured in the laboratory. Then, the ANOVA and Duncan tests were employed due to statistical analysis using of SPSS software package. Also The map of carbon sequestration was prepared using of GIS approach. Results and Discussion :According to obtained results, the amounts of SCS were imposed by different land uses as non-significant. The amounts of SCS were found in forest (4532.35 ton/ha), orchard (2997.66 ton/ha) and paddy rice (2682.55 ton/ha) land use, respectively. The differences may be resulted from the variation among the ecosystem types and plant species. Forests are located in wetlands in the high forest and agricultural land more organic carbon levels (0 to 20 cm), but non-significant difference was observed in the soil depth in these areas. The Increased amount of carbon sequestration in the Orchard of the Paddy Rice can be interpreted due to long-term use of fertilizer in the orchards. In Paddy Rice of study due to deep plowing, results showed more decline of organic matter and the loss of carbon from soils.In addition, the maximumtotal nitrogen, organic and sequestrated carbon in top soil (0-10cm depth) were detected in forest (866.968 ton/ha),whereas the least amount dedicated in paddy rice (393.4 ton/ha) land uses. Four classes of detected soil in the study area were included AlfiSols, Inceptisols, Entisols and Mollisols Conclusions: We found no significant differences in terms of carbon sequestration in land use due to the impact of climate, annually high rainfall and washing clay seems logical. The plant communities in forest ecosystems can become more capable to absorb and retain carbon than other vegetation cover. Agriculture and farming operations are due to dispersion aggregates, reduce of organic matter and carbon sequestration compared to forest intact soils. Considering the vital role of soil carbon sequestration as one of the known values in terms of natural ecosystems and the importance of soil conservation programs, further research works are recommended on the effects of biotic factors such as grazing and land-use changes.

Climate change represents changes in the climate within the earth's atmosphere and its consequences in different parts of the planet. Changes in temperature and rainfall patterns have a great influence on the quantity and quality of water resources, especially in arid regions such as Iran, and consequences of this change on water resources are undeniable. This effect is reported to be on general circulation of the atmosphere, temperature, and precipitation. General atmospheric circulation models are the basis of all studies on climate change phenomena (Su et al., 2016). Because of the large network of these models and the low spatial resolution, some microscopic phenomena in general atmospheres cannot provide an accurate approximation of the climate conditions of the area; therefore, their output should be left to meteorological station’s micro-scale (Perkins et al., 2007).

Background and purpose: The popularity of fermented beverages is increasing due to the preservation of food value and health characteristics of the product during fermentation. Kombucha is a probiotic and beneficial fermented beverage obtained from the social coexistence of bacteria and osmophilic yeasts in a sweetened black tea environment with sucrose. Sucrose is hydrolyzed to glucose and fructose by the invertase enzyme produced by the yeasts in the Kombucha consortium, and fructose is converted to ethanol and carbon dioxide by the yeasts. Despite the excellent health benefits of this drink, it can sometimes be controversial due to the increase in ethanol levels and the issue of halal quality. Results: The final concentration of ethanol alcohol in kombucha varies depending on parameters such as the species of microorganisms present in the solution, temperature, fermentation time and the initial sugar consumption. Using measurements such as controlling the amount of consumed sucrose, regular aeration during the fermentation process, using green and black tea as a substrate, using certain species of microorganisms to reduce the amount of ethanol produced, reducing the pH of the solution during the process and using Alternative sources of sucrose with lower sweetness such as honey and berry juice, can reduce the amount of ethanol produced in kombucha by 0.5%. Conclusion: Kombucha with an alcohol content of less than 3% is considered a non-alcoholic beverage. Using simple and practical solutions, the amount of ethanol produced in the Kombucha solution can be significantly reduced and the miraculous properties of this drink can be benefited.

In recent years, human activities induced increases in atmospheric carbon dioxide (CO2) which caused global warming and climate change. Climate change is anticipated to cause negative and adverse impacts on water systems throughout the world. Higher temperatures are expected to lead to a host of problems. These include melting snowpack, altering both the intensity and frequency of precipitation, increasing evapotranspiration and else. (Delghandi, 2016). Reference evapotranspiration (ETo) is a key hydrological variable quantifying a major water loss from catchments and basins, which can be used to calculate actual evapotranspiration (ETa), scheduled irrigation and prepare input data for hydrological models. The irrigation water requirement basically represents the difference between the crop water requirement and effective precipitation. The only factors affecting ETo are climatic parameters as water is abundantly available at the reference evapotranspiring surface (Allen et al., 1998). The first of climatic parameters is air temperature. As temperature increases, evapotranspiration also goes up. Some study conducted to indicate climate change impact on ET (e.g, Behmanesh et al., 2015; Sheidaeian et al., 2015; Babaeian and Kouhi, 2012). In this study, climate change impacts on reference evapotranspiration (ETo) and precipitation deficit (PD) were studied from 2010 to 2099 in Semnan region. The objective of this study was to examine the climate change impact on the ETo regarding the uncertainty of Atmosphere-Ocean General Circulation Models (AOGCM) and Greenhouse Gases Emission (GHG) scenarios.

The occurrence of wind erosion and the spread of dust particles can be regarded as one of the most important and threatening environmental factors. Climate change and the frequency of droughts have played an important role in exacerbating or weakening these events. The primary objective of the present study was to investigate the trend of changes in four important climatic elements (precipitation, temperature, wind speed and relative humidity) and dust storm index (DSI) in Qazvin city using the Mann-Kendall pre-whitened test and to determine the relationship between them based on the multiple linear regression method. Assessment of the meteorological drought status based on two standardized precipitation index and standardized precipitation, as well as the evapotranspiration index and analysis of their effect on activity level of dust events, was the other objective of this study in the study area. For this purpose, after preparing and processing the climatic data and calculating the dust storm index, the trend of changes and the relationship between climatic parameters and dust events were investigated. The results showed that the changes of trend in the annual precipitation and relative humidity in Qazvin city were increasing, while the trend of annual changes in the wind speed and the mean air temperature was a decreasing one. Investigation of the monthly changes in the dust events also showed that there was a sharp decrease in the occurrence of wind erosion and the spread of domestic dust particles only in July. On a seasonal scale, with the exception of winter that has been reported without trends, in other seasons, the intensity of these events was significantly reduced. The effect of the meteorological drought on wind erosion was estimated to be 11% at the confidence level of 99%. In general, these findings indicate a decreasing trend of land degradation and desertification caused by wind erosion in Qazvin.

The principle of economically optimal design of water conveyance and water supply systems has been one of the major concerns of researchers and designers for along time. In order to design a hydropower plant many combinations of headrace tunnel, penstockand surge tank sizes may be selected.The designalternative that has a maximum benefit-cost ratio is the one which must be sought. be selected that has the maximum benefit-cost ratio. In this paper, unsteady flow analysis is performed initially to get maximum pressures in headrace tunnel and penstocks and maximum water elevation in surge tanks. Based on these results structural design of headrace tunnel, penstocks and surge tanks is done. Total cost of the project is then calculated. Having calculated the head at turbines, sales of power and revenues are determined to get the benefit-cost ratio. It is obvious that for every selected size of involved structures, hydraulic and optimization analyses should be done. The genetic algorithm optimization technique is utilized for optimal design of headrace tunnel, penstocks, and surge tanks. The benefit-cost ratio is considered to be the objective function in the optimization analysis. The hydraulic and optimization analyses have been linked in an iterative procedure to develop a general model for optimal design of hydropower plant projects. The accuracy and convergence of the developed model have been quite satisfactory.

Background and Objectives: Cadmium can enter water resources through the industrial wastewater. It could cause intensivly damages to the liver and kidney of humans. Magnetic iron nanoparticles are used to control and eliminate heavy metals from industrial effluents through the mechanisms of adsorption, ion exchange and electrostatic forces. The aim of this study was to evaluate the efficiency of magnetic nanoparticles for adsorption of cadmium. Methods: The magnetite nanoparticles were prepared by co-precipitation method through the addition of bivalent and trivalent iron chloride under alkaline conditions. Characteristics of nanoparticles including particles structure, composition and size were determined using analytical devices such as XRD, SEM, and FT-IR. For optimization of adsorption process of cadmium, some parameters such as pH, contact time, initial concentration of cadmium, nanoparticles concentration, and temperature were studied under different conditions. Results: It was found that 95% of cadmium could be removedAt pH ≥ 5.6, 10 mg/L initial cadmium concentration, a dose of 1 mg synthesized magnetite nanoparticles, 10 minutes contact time, and 200 rpm mixing rate at 25 °C. The isotherm of adsorption follows the Langmuir model (R2 < 0.995). Maximum capacity of cadmium adsorption was found to be 20.41 mg/g. Conclusion: Magnetite nanoparticles exhibit high capability for removal of cadmium. The nanoparticles synthesized could be used at industrial scale because of having the magnetic property, which make them easily recovered from aqueous solution through applying a magnetic field.

Background and Objectives: As a green fuel and environmentally friendly energy, biodiesel has recently attracted much attention and efforts are ongoing to optimizing biodiesel production from microalgae’s. The aim of this study was to determine the appropriate method of dewatering and drying biomass and selecting a suitable organic solvent for extraction lipids from biomass. Materials and Methods: After culturing Nannochloropsis Oculata in Gillard F/2 medium and reaching at the end of the stationary growth phase, algal biomass was separated from aqueous by centrifuge and drying in three methods: fore, air-dried and lyophilized. Lipid extractions of each sample was performed using soxhlet apparatus and three solvents including diethyl ether, n-hexane and n-pentane. At each stage, the quantity and quality of the extracted lipids was determined by gas chromatography. Results: In all three drying methods, palmitic acid and palmitoleic acid were significantly the main fatty acid composition of microalgae. The fatty acid composition of palmitic acid extracted by diethyl ether was significantly more than the other two solvents. Maximum production of triglyceride was observed in air dried and lyophilized (using diethyl ether solvent) microalgae as 75.03 and 76.72 % of fatty acid respectively. Conclusion: The use of lyophilized method for dewatering and drying of biomass and diethyl ether as solvent for the extraction of lipids from biomass yielded more compared with other methods studied in this paper and would be more efficient in research works related to the production of biodiesel from microalgae’s lipid.

Abstract Background: Increase of nitrate concentration in water sources is becoming a serious problem in many parts of the world. Nitrogen containing compounds released into environment can create serious problems, such as eutrophication of water sources and hazard potential to human health, because it has potency of causing methemoglubinemia disease and cancer. Between recommended methods, biological denitrification is an effective method to remove nitrate from water and wastewater. Materials and methods: In this study, biological nitrogen removal process was evaluated using ethanol, methanol and succinate as different organic carbon sources in batch scale. The different parameters, carbon source, initial nitrate concentration, pH, and inoculated of bacteria were evaluated. Results: The experimental results were showed that bacteria can not use methanol as carbon source. The dinitrifyers bacteria can dissimilate 200 mg/L No3-N, in the optimum condition: 28 ºC, pH 7.2 and initial inoculation of 3×108 CFU/ml, respectively. In the process, produced nitrate-N was less than 1 mg/l. Conclusion: The bacterium Pseudomonas stutzeri can use ethanol as carbon source for biological denitrification, but efficiency of succinate was better than ethanol.