Showing 9 results for Ravesh
R Ravesh, B Shiran, A Alavi, J Zarvagis,
Volume 13, Issue 47 (4-2009)
Abstract
In this study, 45 Pleurotus isolates with a wide range of geographical origins (in five provinces of Iran: Isfahan, Chaharmahal Bakhtiary, Kohkiloye boyrahmad, Lorestan and Fars) were collected. A random amplified polymorphic DNA polymerase chain reaction (RAPD-PCR) was used to assess the genetic diversity in ten populations of the Pleurotus eryngii complex. The use of ten primers allowed the production of 150 polymorphic bands. In addition, the evalution of the principal ecological and morphological characters provided further evidence for discriminating between populations. The results show a higher level of diversity of RAPD polymorphism in the populations. 28.67% of the RAPD diversity was among populations and 71.33% was within populations. In the RAPD patterns, Pleurotus strains growing on Ferula assa-foetida, Ferula ovina and Prangus ferulacea formed distinct groups. In this study, the resolution of the RAPD-PCR analysis was better than the morphological analysis.
M. Khoshravesh, J. Abedi-Koupai, E. Nikzad-Tehrani,
Volume 19, Issue 74 (Winter 2016)
Abstract
During the past few decades, the southern part of the Caspian Sea has more frequently experienced extreme climatic events such as drought and flood. Trend analysis of hydro-climatic variables was conducted using non-parametric Mann-Kendall test and regression test for Neka basin in the north of Iran. Trends of precipitation and stream flow characteristics including maximum flow, mean flow and low flow indices were analyzed at the annual, seasonal and monthly time scales from 1358 to 1391 (34 years). Results showed a general decrease in annual and winter precipitation and decrease in daily maximum precipitation, with an increased trend in daily maximum precipitation of spring season. A decreasing trend was observed in 7-day low flow in summer for all sub-basins. Annual and monthly mean flows specifically in winter in all sub-basins decreased, but annual maximum flow increased from upstream to downstream. Land use changes showed that deforestation and urbanization increased during 34 years in the mid and downstream sub-basins. The analysis showed that low flow indices and mean flows are strictly sensitive to climate change. Overall, from hydrological perspective, these results indicate that the study region is getting dryer and facing more severe drought events. The results of this study can predict future droughts to make better decisions for irrigation planning and management of water resources.
M. Khoshravesh, M. Valizadeh,
Volume 21, Issue 2 (Summer 2017)
Abstract
Construction of a dam in the upstream of Tajan basin, as one of the human activities in order to provide drinking water, hydropower, agriculture, flood control or other purposes, can be effective on other sectors such as water resources. The purpose of this study is investigating the impact of Rajaei dam on groundwater resources in Sari-Neka plain during 26 years period (1985-2011) using geostatistical method, parametric and non-parametric tests. The results of statistical tests showed that groundwater table variation during 26 years has experienced insignificant upward trend. Quality factors such as EC, TDS, TH, Cl, SO4, Mg, Na and SAR had significant downward trend at 5% confidence level for Pearson and Kendall test. The Quality changes of groundwater resources in the region had good condition due to construction of dam. The results of spatial analysis for the study area using Kriging interpolation method in the three years for 1985, 1999, 2011 showed that in 1999 (the year of exploitation of the dam) most of the quality factors had reached the highest level from 1985 until the dam operation (1999) and then decreased to 2011. The results of this study showed that, agricultural activities after dam construction, operation of irrigation system and drainage network design of Rajaei dams, have raised the water table in northern part of the region and consequently had a significant impact on the quality of water resources.
H. Dabbaghi, M. Khoshravesh, M. A. Gholami Sefidkouhi,
Volume 22, Issue 2 (Summer 2018)
Abstract
Emitter clogging for using agricultural wastewater increases the operating costs and reduces the motivation of farmers. The new method to reduce the emitters clogging is the use of a Merus ring that does not have the problems of chlorination and pickling methods, such as pollution and high cost. Due to the importance of agricultural wastewater use, this study investigated the emitters clogging and the effect of Merus ring on the emitter's efficiency in a trickle irrigation system. The treatments including irrigation water (well water and wastewater) and modified water (irrigation with Merus ring and irrigation without Merus ring), as the main factor and the emitters type treatment including Irritec (D1), Corona (D2), Axios (D3), Netafim (D4), Polirood (D5), and Paya (D6) as the sub treatments were performed in three replications. The results showed that the agricultural wastewater caused the emitters clogging in irrigation water and modified water treatments, but over time, the Merus ring had a positive effect on the evaluation parameters of the emitters. For agricultural wastewater, in the first and last irrigation periods, the average discharge of emitters with the Merus ring was 0.05 and 0.33 Liter per hours, respectively, more than the treatment without the Merus ring. The uniformity coefficient of emitters in the first and last irrigation periods, in well water with the Merus ring, was 0.31%and 6.67%, respectively, more than that in the well water without the Merus ring. Also, the uniformity coefficient of emitters in the first and last irrigation periods in agricultural wastewater with the Merus ring was 0.85% and 12.10%, respectively, more than that in agricultural wastewater without the Merus ring. At the end of irrigation period, the results showed that Netafim and Axios had the best and weakest efficiency, respectively. In general, the emitters used in the treatment of well water with the Merus ring had the highest discharge and the emitters used in the treatment of wastewater without the Merus ring had the lowest discharge.
S. Shiukhy Soqanloo, S. Golshan, M. Khoshravesh,
Volume 22, Issue 4 (Winter 2019)
Abstract
The effects of climate change can be released from the surface to the soil depth, thereby affecting soil thermal regime. Thermal energy in the soil plays a very important role in causing climate changes. In this study, for the assessment and detection of the climate changes, soil depths temperature, the measured data related to the daily air temperature at a height of 2 meters (screen) during the years (1951-2014), and the soil depths daily temperature (5-10-20-30-50 to 100 cm), for 3, 9 and 15 hours, were obtained during a period (1992-2014) in Shahrud station. The climate change detection was employed to compare the treatment mean. As well, for detection of trends related to the annual, seasonal and monthly time series and their relation to the soil depths temperature, parametric methods (regression analysis and Pearson) and nonparametric (Mann-Kendall, Spearman) were applied. The results showed that the soil temperature was increased in all months except January, February and March. Also, in the seasonal time series, the soil depths temperature was increased in all seasons except winter. In fact, based on the results, the soil temperature in spring, summer and autumn was increased. Detection trends of the annual soil depths temperature showed that, except for the Pearson correlation coefficient method, soil temperature was increased at all soil depths.
A. Darzi-Naftchali, S. Rafierad, M. Khoshravesh, A. Asgari, M. R. Babaei, H. Zabardast-Rostami,
Volume 23, Issue 1 (Spring 2019)
Abstract
Water is a vital source for both human and biological living. Today, water management and conservation, not only both in developing countries but also in and the developed countries ones, has is of great importance. In the traditional economy, water is not considered as a productive factor in the national accounts; however, but in reality, water is the primary factor in many direct and indirect goods and services. To evaluate the effect of growth in the added value of agriculture, industry and electricity sectors on the added value of water sector in the Mazandaran province, coefficients of ARDL model were estimated using the Micro fit software. The extended Dickey-Fuller unit root test was used for the statistical test of variables. The static test of variables showed that all variables were significant at the 95% confidence level and were also consistent with the theory. A 1% increase (decrease) in the added value of industry and electricity resulted in the increase of 0.54 % and 0.39 %, respectively, increase (decrease) in the added value of the water sector, respectively. Also, 1% increase (decrease) in the added value of the agricultural sector caused in a 0.54% increase (decrease) in the added value of the water sector. Industry and electricity sectors affected the added value of water sector more than agriculture. In the long-term, the growth of the added value of the industry sector had the greatest impact on the growth of the added value of water sector. Based on the results, controlling water use in agriculture, industry and electricity sectors increases increased the effects of the added value of these sectors on the added value of the water sector.
S. Nikkhoo Amiri, M. Khoshravesh, R. Norooz Valashedi,
Volume 23, Issue 4 (Special Issue of Flood and Soil Erosion, Winter 2019)
Abstract
Today, the rising surface temperature of the planet and its effects on the water cycle have attracted the attention of many researchers. The aim of this study was to investigate the effect of climate change on the Tajan (the upstream of Shahid Rajaei dam) catchment area. In order to study the output of CanESM2 model, the SDSM method was used to estimate the magnitude of the data. Flow discharge changes in Shahid Rajaei Dam were simulated using the weather data of Kiasar synoptic station and the temperature and precipitation changes were simulated using the climate scenarios of RCP2.6 and RCP8.5 for the 2016-2066 period. Also, the effect of different scenarios on the outflow of the Soleiman Tangeh hydrometric station was evaluated by SWAT hydrologic model. The results showed that the annual precipitation would be decreased by 58% and the air temperature would be increased by 14% under RCP2.6 scenario. Also, in the RCP8.5 scenario, precipitation would be decreased by 59.5% and the temperature would be increased by 21%. Peak discharge for RCP2.6 and RCP8.5 scenarios would be increased by 4% and 5.7%, respectively, and the average annual discharge might be decreased by 16% and 16.5% in the future period (2016-2066). Therefore, it can be planned by the investigation of conditions for cropping patterns in the downstream to consider the environmental impacts for future periods.
T. Dehgan, M. A. Gholami Sefidkouhi, M. Khoshravesh, N. Samadani Langroudi,
Volume 25, Issue 1 (Spring 2021)
Abstract
In this research, the nitrate removal by beech leaves was investigated in batch and column systems. The batch experiment was performed to address the effect of pH, contact time, adsorbent dosage and initial nitrate ion concentration on the nitrate removal. The results showed that with an increase in pH, the removal efficiency and adsorption capacity were decreased and nitrate removal by millimeter and nano adsorbent beech leaves reached equilibrium 120 and 90 minutes after experiment, respectively. With an increase in the nitrate concentration, the removal efficiency was decreased from 59.2% to 39.7% and 82.1% to 69.9% for millimeter and the nanoparticles of Beech leaves, respectively. In fixed-bed column adsorption experiments, the flow rates of 5, 8 and 11 ml/min and the nitrate concentration of 15, 50 and 120 mg/L were studied. The results showed with an increase in the nitrate concentration from 15 to 120 mg/L, the saturation time was decreased from 240 to 150 and 360 to 270 minutes for millimeter and nanoparticles of Beech leaves, respectively. Thomas, Dose-response and Yoon-Nelson models were fitted to the results of the continuous experiments. The Thomas model fitted the experimental data with high accuracy. Compared to the adsorbents, nano-adsorbent had more adsorption capacity in the batch and column systems.
M.h. Sadeghi Ravesh,
Volume 26, Issue 2 (ُSummer 2022)
Abstract
The optimal strategy selection is an influential factor to enhance the efficiency of land reclamation projects. On the other hand, the process of desertification of the land during environmental degradation is the consequence of the interaction between various factors that make it challenging to select appropriate solutions. Therefore, this study aimed to provide systematic optimization strategies in the form of a group decision-making model in the Yazd-Khezrabad plain. The important strategies were identified using the Delphi model. Then, the alternative initial ranking was formed by Cook and Seiford method framework using the vote taken from the decision makers on strategies. Finally, by estimating the linear distance of each option and including the matrix of the intervals, the last priority of the strategies was obtained from solving the assignment problem. The results indicated that the strategies of "prevent land use inappropriate change" (A18) and "the regeneration of vegetation cover" (A23) with Value=1 and Reduced Cost=0, were identified as the most important combating-desertification strategies in the region, respectively. The results of this study help desert managers to utilize limited facilities and capital dedicated to controlling the desertification process efficiently and effectively.
