فهرست مطالب amirhosein javid

Eddies formation is an important oceanic phenomenon that plays a significant role in the transport of fluid in the ocean. The main eddy in the Persian Gulf is mainly due to factors such as wind, tide and density variations. This paper uses the HD model of MIKE3D packages to perform the simulations; first a large-scale flow model is implemented for the entire area of the Oman Sea and the Persian Gulf, and then the formation of mesoscale in the Persian Gulf and the Oman Sea is simulated by the output of Model 3 MIKE with a resolution of ten kilometers for 2013 in 30 layers of Sigma and Z coordinates. Almost all year round, a thermohaline stream enters the Oman Sea Persian Gulf and penetrates deeper areas, causing fluctuations in the temperature and salinity in the Oman Sea. This thermohaline flow that enters the Oman Sea causes temperature changes and these changes cause the formation of eddy in the Oman Sea. It was also seen that a coastal stream in the northwest direction from the north of the Strait of Hormuz enters the Persian Gulf and there is a southwest stream in the southern part of the strait. The main eddy in the Persian Gulf is clockwise and it was observed that the general shape of the eddy in the Persian Gulf is clockwise and the counterclockwise eddy in the center of the Persian Gulf becomes stronger from April to July and in August, it has the highest resolution. In this study, more attention was paid to the months when eddy has more clarity.

So as to conserve and manage reservoirs effectively, a comprehensive awareness is necessary for the spatial and temporal pattern of water quality.  

. In this research, a three-dimensional EFDC dynamic environmental model has been utilized, for the assessment and simulation of the thermal-regime and quality parameters of the Mamloo-Dam Reservoir. The information required for the calibration and validation of the model in the 12 months of the year of 2019, has been taken from 6 stations.

The thermal stratification has prolonged, for several months. Stability in stratification has obstructed the transfer of oxygen to the lower layers and the dissolved oxygen (DO) concentration in the hypolimnion, decreases intensely, in to less than 2 mg/L. In the entire seasons of the year, the highest concentration of Chlorophyll is relative to photic zones (with highest concentration 35.6 µg/L in august). The phosphorous factor restricts the growth of algae in the reservoir; and a high correlation between the modifications in total phosphorous concentration and chlorophyll was observed. The trend of modifications in total nitrogen illustrates its control by external input loads. Furthermore, the results attained in comparing the simulated and real values (R2 and RMSE values), display that the EFDC model has the capacity to simulate the hydrodynamic and qualitative parameters of the Mamloo-Dam Reservoir. Moreover, provided appropriate statistical indicators (RMSE=0.15, R2=0.72) in water level simulation.

One of the key factors in the conservation and development of urban green space is use of available water resource in each region according to the characteristics of green space in this paper providing of water for boeen-zahra's green space irrigation has been studied.

First available water resources were determined then questionnaires completed by experts, and the effective criteria in the decision-making process of water resources selection were weighed using AHP (Analytical Hierarchy Process) method. Finally, the best option was selected using the preferential prioritization method to enrich the evaluations (Promethee).

The results of AHP method in Expert Choice software indicated that the weight of technical, practical and managerial criteria were higher than other options and water resources of municipal garden wells with miscellaneous wells were selected as the best option. In the second stage, the weights and scores obtained from the criteria and options of the first part, were selected and ranked as input to the Decision Lab 2000 software, and in this stage, the result obtained was confirmed in the first stage.

The present study indicates that technical, practical, managerial and environmental criteria are the most important factors in choosing the type of water source for irrigation of green space. In other words, in choosing the right water resources, achieving standards, hydraulic shock resistance, no need for advanced technology to control, system efficiency, are the parameters that are most considered.

Environmental pollution due to heavy metals has increased enormously in the world in the last two centuries. The presence of some heavy metals in aquatic ecosystems is a continuous hazard to human health. Electrospinning technology is the most effective way to produce nanofibers. In this study, the technology of producing nanofiber aluminum for maximum separation of nickel through the adsorption process has been investigated. In this research, nanofiber alumina has been synthesized by electrospinning method. Spinning solution with a concentration of 10% by weight of aluminum precursor was selected. Considering different weight ratios of polymer to precursor, the electrolysis process was better selected. The stable spinning voltage was in the range of 17-20 kV and the flow rate was 0.5 ml/h. Eventually, XRD, SEM, FTIR, and Raman tests were performed to ensure the formation of nanoparticles and to determine their physical, chemical, and morphological structure. The pH, contact time, nano-adsorption value, pollutant concentration, and solution volume parameters were evaluated. Therefore, the optimal conditions for separating nickel-metal were provided and isothermal and kinetic absorption calculations were performed for it. The results indicate that the best conditions for nickel adsorption by this type of nano-adsorbent occurs at pH=8, a contact time of 60 minutes, nano-adsorbent in the amount of 0.05 gr, concentration of 5 mg/L of nickel metal and the solution volume of 50 ml and it has been 99%. In addition, the adsorbent behavior was consistent with the Langmuir and Freundlich isotherms and the first and second-degree quasi-quintet kinetic models. Finally, it is clear that the method of nanofiber aluminum synthesis by electrospinning is complex but at the same time very practical and effective, leading to its use as a new and promising solution in removing nickel metal ions from water.

ABSTRACT This study investigates the performance of modified Nano tin(IV) oxide sorbent in oil pollution removal from sea water. This sorbent synthesized in two stages: synthesizing tin(IV) oxide nano particles and modifying its surface, using (3-mercaptopropyl) trimethoxysilane and grafting of N,N-dimethylacrylamide-allyl butyl ether copolymer on it. The resulting sorbent was characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, and scanning electron microscopy, then evaluated for TPH adsorption from environmental water samples. Total Petroleum Hydrocarbons (TPH) is considered as water pollution index and measured by Gas Chromatography. Batch experiments were conducted to evaluate the effect of analytical parameters of pH, contact time, and temperature. The optimum pH was 5 and contact time was 10 minutes. The capacity of the sorbent was 11.46 mg g-1. Results showed good accessibility of the active sites. The equilibrium adsorption data of TPH sorption onto grafted nano-tin(IV) oxide were analyzed using the Langmuir and Freundlich isotherm models. The adsorption data was modeled as pseudo-first-order and pseudo-second-order kinetic equations. The results show that adsorption followed by the Langmuir isotherm and the pseudo-second-order model. The sorbent removed more than 80% of the TPH from the water solution samples. Key words: Oil removal, TPH removal from water, Nano tin oxide, Modified sorbent 1. Introduction Oil pollution has several long-term effects on environment and economy. Cleaning oil pollutions and oil spills are very expensive, and among different methods for removing oil from water, such as physical methods, adsorption, and biological treatment, adsorption methods are widely applied. Nano-materials have interesting characteristics that make them promising sorbents in aqueous solutions. Surface modification of nano-materials by grafting of polymer chains enhances their structural properties and sorption capacity. This study focuses on removing oil pollutions from water by synthesizing an efficient nano-sorbent. Tin(IV) oxide (SnO2) nano-particles were synthesized using the co-precipitation method; after modification by 3-mercaptopropyl trimethoxysilane, they were grafted with N,N-dimethylacrylamide and allyl butyl ether. The performance of this grafted synthesized nano-sorbent was then evaluated for use in oil adsorption from water. 2. Materials and Methods 2.1. Synthesis of SnO2 nano-particles grafted with hydrophobic groups 2.1.1. Synthesis of nano-SnO2 At the first stage, SnCl2.2H2O (116.3 g) was dissolved in 250 ml distilled water to prepare 2 M SnCl2.2H2O solution. Then, 2 M NH3 solution was added gradually to the SnCl2 solution while stirring at room temperature (25°C) to reach pH = 7. The slurry was stirred for 2 h and then filtered and dried. 2.1.2. Polymer grafting A two-step method was applied for this stage. The first step was modification of SnO2 with 3-mercaptopropyl trimethoxysilane and second step, Graft polymerization, was grafting the N,N-dimethylacrylamide (DMAA)- allyl butyl ether (ABE) copolymer onto the modified SnO2. First step SnO2 nano-particles were silylated using an anhydrous solution of 5% 3-mercaptopropyl trimethoxysilane in 1,4-dioxane. A mixture of SnO2 nano-particles (3 g), 1,4-dioxane (2.5 ml) and 3-mercaptopropyl trimethoxysilane (47.5 ml) was refluxed for 24 h at 100°C. The solid precipitate was filtered and washed several times with 30 ml of 1,4-dioxane and dried under vacuum in a desiccator over dry calcium chloride. Second step In this stage, a mixture of modified SnO2 nano-particles (3 g), ethanol (30 ml), ABE (4 ml), DMAA (1 ml) and 2,2'-azobis (2-methylpropionittrile) (0.1 g) was prepared and the mixture was refluxed in a nitrogen atmosphere for 8 h at 65°C. The grafted particles were filtered and washed with ethanol and water and then dried. This poly-grafted nano-SnO2 with (ABE-co-DMAA) is named AD-GNS. 2.2. Oil pollution index assessment Total Petroleum Hydrocarbon (TPH) is considered as an index assessment of oil pollution in water, and this index is measured by Gas Chromatography (GC). 2.3. Batch adsorption experiments A set of solutions (each 200 ml) containing crude oil and water were prepared and their pH values adjusted to the optimum value of 5. Then each 200 ml solution was divided to two 100 ml solutions, and one of them considered as standard solution for initial TPH assessment. Then desired dosage of AD-GNS was added to other 100 ml solution and it was shaken for 1 hr. The sorbent was filtered, and the suspensions were centrifuged at 7000 rpm for 5 min and the clear supernatant and the standard solution were analyzed using a GC-FID. 2.4. Parameters optimization for sorption and isotherm study In this study, the effects of initial pH, contact time, and adsorbent dose were investigated to obtain the optimize condition for adsorption of oil on AD-GNS. Then adsorption isotherms, Langmuir and Freundlich isotherms, and adsorption kinetic models, the pseudo-first-order and the pseudo-second-order, are applied to investigate the mechanism of adsorption and efficiency of oil removal. 3. Results and Discussion The AD-GNS was characterized by FTIR, TEM and SEM. FTIR of the SnO2 nano-particles confirmed the presence of Sn-O-Sn and O-H. A peak at 1091 cm-1 caused by the Si-O band in the FTIR of the modified SnO2 nano-particles confirms the modification with 3-mercaptopropyl trimethoxysilane. The presence of CH2, CH, and OH are confirmed by FTIR. The IR spectrum of the AD-GNS was compared with that of the modified SnO2nano-particles. Two additional bands appear at about 1103 and 1641 cm-1 that correspond to C-O and C=O, respectively. TEM showed spherical agglomerated micro-particles with diameters of less than 100 nm, and SEM confirmed that particle size for AD-GNS was ranged from 30 to 50 nm. The degree of oil sorption by pH value was determined using the batch equilibration technique at pH values ranging from 3 to 8. Fig. 1(a) shows the effect of pH on the sorption of oil. Evidently, adsorbate uptake depended on solution pH and the maximum adsorption was achieved at a pH of 5. The effect of contact time on the adsorption of TPH was investigated at different initial concentrations of oil and an optimized pH of 5. The AD-GNS amount was constant during this stage. As seen in Fig. 1(b), oil uptake was rapid at the start of the process in response to the huge surface area with functionalized and available active sites, but then slowed. The adsorption rate became constant as the active sites were covered with xylene and equilibrium was reached. As seen, at lower initial concentrations, adsorption was faster, and 10 minutes was usually enough for complete sorption. This reflects that active sites on the sorbent are easily accessible. The effect of adsorbent dose is also evaluated by adding different dosage of AD-GNS to solutions with constant TPH value and pH=5. The results are shown in Table. 1. For better interpretation of the results of Table. 1, Langmuir and Freundlich isotherms, can be determined, and results are listed in Table. 2. As shown in Table 2, RL =0.02, and it is in the range of 0-1, which shows highly favorable adsorption. The maximum adsorption capacity of AD-GNS for complete monolayer coverage on the surface (qmax) is 11.61 and it confirms the very high capacity of the synthesized sorbent. To analyze the data and evaluate the mechanism of adsorption and efficiency of oil removal, two adsorption kinetic models, pseudo-first-order and pseudo-second-order, are applied, and proves that the pseudo-second-order model presents the adsorption kinetics better. 4. Conclusions A new sorbent synthesized by a two-stage method. Although the synthesis of the sorbent is simple and economical, it is time-consuming. The optimum pH for oil removal from water by the sorbent was 5, and contact time was 10 minutes. The capacity of the sorbent was 11.46 mg g-1. Results showed good accessibility of the active sites. The equilibrium adsorption data of TPH sorption onto grafted nano-tin(IV) oxide were analyzed using the Langmuir and Freundlich isotherm models. The adsorption data was modeled as pseudo-first-order and pseudo-second-order kinetic equations. The results show that adsorption followed by the Langmuir isotherm and the pseudo-second-order model. The sorbent removed more than 80% of the TPH from the real water solution samples.

Water has always some soluble salts, such as sulphate. Sulphate enters the water through different resources such as, dissolved gypsum, waste water of industrial factories and automobiles smoke, dissolved in rain. Presence of sulphate in potable water has an enormous role in creating constant hardness.On the other hand Presence of sulphate with high density in drinking water, causes changes in taste and it's combination with Calcium and Magnesium anions has laxative effect. The goal of this study is to assess the amount of existing sulphate in Yasuj city potable ground water, and determining the procedure of changes in chemical parameters of sulphate and recognizing effective factors on these parameters and preparing qualitative plan for water resources for sulphate parameter by means of GIS tools.
In the study described above, 42 specimens in the 7 earely months of the year 1387 were acquired and tested. Sulphate tests were done based on the measuring method of the instrument of Filter photometer (Model: 7000). For analysing the results, Excel software and for preparing qualitative plan, GIS software was used.
This study showed that sulfate levels in water resources by reducing water level in summer and autumn and with a water level of under ground water resources increases.
Decrease of ground water resources of Yasuj city, causes the sulphate density to increase.

In this study، NASIR program is implemented to numerically simulate the temperature field near the intake/outlet of Paresar thermal power plant and assess the environmental provisions. According to low depth of coastal regions، two-dimensional depth-average governing equations and convection and temperature diffusion relationships are considered and solved by a finite volume method in NASIR program. Coastal boundary condition، currents and out-let discharges of the power plant are considered in the modeling and the performance of the numerical method is estimated in the coastal region near the thermal power plant to assess the excess water temperature. According to the current environmental provisions، the efficiency of the intake/outlet system is evaluated.

Using the sludge as fertilizer on farms is one of the options to dispose it, which due to its variety of pathogenic microorganisms, it may cause a wide range of bacterial and parasitic diseases in human and livestock. The purpose of this study is to investigate the feasibility of using dried sludge produced in municipal wastewater treatment processes to fertilize agricultural lands in accordance to the health and environmental standards.

In this analytical-descriptive study, three sewage treatment plants of Chahar Mahal and bakhtiary province were selected as the sample plant, including Shahrekord, Farsan and Borujen due to their similarity in the weather condition and the treatment process. In order to investigate the sludge in its lowest and the highest rate of evaporation, in the freezing cold winter and burning hot summer respectively, two winters and two summers were selected as the timeframe. In this study, faecal coliform and total coliform were determined as the sludge microbial indexes and examined in accordance to the EPA standards.

The findings of this study indicated that the mean value of faecal coliform for the three treatment plants in winter were 1.63 × 106, 1.93 × 106 and 1.98 × 106 respectively. Also in summer they were 4.51 × 106, 5.75 × 106 and 9.23 × 106 respectively.

The evaluations of this study indicated that the biological sludge generated from the three treatment plants in the winter after drying off naturally were located in class B of the EPA standards. Thus, based on recommendations of the organization, such sludge can be used with regards to standard restrictions for agricultural purposes. However, the microbiological quality of the sludge in summer was lower than the U.S. EPA standards for Class B sludge, and thus is not applicable in agricultural use.

Due to the plentiful abilities of GIS and its usage in various knowledge's specially water andwastewater, usage of GIS because of abundant advantages compare of its disadvantages is ascompleted and very suitable software for designer engineers. In this research has been investigatedusage of ArcGIS for determination of demanded parameters for sewerage designing in studying zone(Nabovat minicity in the Ilam province).In this research, ArcGIS was used as perfected software and SewerCad was used asaccounting software. Therefore sewerage designing was devided to below phases:First phase: Pipe length, zone area of covering a pipe and interpolation of earth height digits onmanholes were determined by ArcGIS software.Second phase: Data related to characteristics of topography, meteorology and statistical (forexample, population, water and wastewater capita) were prepared.Third phase: Ago data were used for analysis by SewerCad software.Fourth phase: Usage of ArcGIS software was compared with similar softwares as qualitative.Results of this research showed: Usage of ArcGIS software for data determination of seweragedesigning, eliminated main defects other softwares used for this object and increased precision,quickness and readiness of data determination for sewerage designing (for example: defection ofAutoCad software for covering area determination of each pipe by selection a point on pipe).