Investigation on the trophic status of Ekbatan reservoir: a drinking water supply reservoir in Iran

BACKGROUND: Eutrophication is one of the detrimental environmental problems in water reservoirs dye to the irregular introducing nutrients (phosphorus and nitrogen). This study aimed to explore the eutrophication state of Ekbatan Reservoir, Hamadan, western Iran. METHODS: Monthly sampling was conducted during April 2010 to March 2011. Seven sampling stations were selected in the various locations of the reservoir and the samples were collected in the depth of 50 cm. The grab sampling of water for nitrogen, phosphorous and chlorophyll-a was carried out at all localities by Hatch sampler. The trophic state of the dam was determined by Carlson's Trophic State Index (TSI) and Chapra's classification. RESULTS: The highest concentrations of phosphorus and chlorophyll-a were measured in August and the lowest concentration for both of the parameters was determined in February. The TSI index according phosphorus concentration showed that the reservoir was in eutrophic status during May to November and was in mesotrophic status over November to May. CONCLUSIONS: It seems that the eutrophication process in the lake was resulted from the rural wastewaters and agricultural fertilizers. Therefore, using long term management methods including prevent of uncontrolled discharge of agricultural wastewaters is recommended in order to reduce the eutrophication in the reservoir. Decrease of phosphorus concentration in the dam by 50 can convert the eutrophic state to mesotrophic state

The Effect of Dust Storm on the Microbial Quality of Ambient Air in Sanandaj: A City Located in the West of Iran.

BACKGROUND & AIMS: The presence of pathogenic microorganisms in the dust storm can cause diseases such as Asthma, Pneumonia, and respiratory infections. The aim of this study was to determine the relationship between air-borne particles with airborne microorganisms in normal and dusty days in Sanandaj, a city located in the west of Iran. MATERIALS & METHODS: Air sampling was conducted during the normal and dusty days through Andersen single-stage impactor (28.3 L/min) for 2.5 min. Air particles concentration (PM10) was measured daily and microbial sampling was also conducted on every six days and on the dusty days. Finally, the data was analyzed by SPSS-16 (ANOVA and paired T-tests). RESULTS: The concentration of airborne microorganisms (bacteria and fungi) was increased by an increase of the airborne particles. Particles concentration in May, June and July (twice per month) was more than of the standard value. The predominant species of bacteria and fungi during the occurrence of Dust storm was Bacillus spp. (56.2% of total bacteria) and Mycosporium spp. (28.6% of total fungi), respectively. DISCUSSION AND CONCLUSION: The results showed that the number of airborne microorganisms (bacteria and fungi) increased during the dust storm. Therefore, the microorganisms in the dust storm can cause biological harmful effects on human health

Human health risk assessment due to ambient PM10 and SO2 by an air quality modeling technique

Exposure to air pollutants may be an important environmental risk factor for human health. The main objective of this study was to assess the health impacts of exposure to particulate matter of aerodynamic diameter <= 10 mu g (PM10) and to sulfur dioxide (SO2) using the AirQ2.2.3 software developed by the WHO European Center for Environment and Health. Daily concentrations of PM10 and SO2 were used to assess the health effects. With regard to the mortality, the results showed that 3.9 (95 CI: 3.3-4.5) of total, 4.2 (95 CI: 2.7-9.05) of cardiovascular, and 6.2 (95 CI: 4.2-16.9) of respiratory mortality were related to PM10 concentrations above 10 mu g/m(3), respectively. In addition, 1.7 (95 CI: 1.3-2.06) of total, 3.4 (95 CI: 0.78-5.0) of cardiovascular, and 2 (95 CI: 2.5-5.7) of respiratory death were attributed to SO2 levels higher than 10 mu g/m(3), respectively. Given these findings, urgent policy decisions are needed to reduce the death caused by air pollution, and better quantification studies are recommended. (C) 2017 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved

Insider trading and the forecast of future stock returns—Study on Chinese stock market

自从2006年新的《证券法》施行以来，在高度繁荣的金融市场中，内部人交易作为影响股票市场波动的重要因素越来越受关注。本文研究的重点就在于内部人交易对股票市场预期收益的预测。通过对2006年到2014年间的中国股票市场数据进行分析研究，本文在内部人总交易净次数这一指数的基础上，又建立了一个全新的内部人总交易净市值指数，不同于单纯考虑交易次数的行为，在新指数中充分考虑了市场价格和交易量因素，从市场资金量的方面定义新指数，更加精确的预测股票市场未来的收益波动。通过对内部人总交易净次数和净市值这两项不同指数在不同期限长度下，利用线性模型预测股票市场超额预期收益，本文分别采用过去1个月、3个月、6个月、...The focus of this paper is whether insider trading has important impact on the future return of the stock market, and how much effect this paper can predict. Based on the China stock market data from 2006 to 2014, this paper first uses the aggregate net number of insider trading to design models in different periods. But most importantly, this paper designs a new index named aggregate net market v...学位：经济学硕士院系专业：王亚南经济研究院_金融学(含保险学)学号：2772012115261

Active removal of waste dye pollutants using Ta[sub]3N[sub]5/W[sub]18O[sub]49 nanocomposite fibres

A scalable solvothermal technique is reported for the synthesis of a photocatalytic composite material consisting of orthorhombic Ta3N5 nanoparticles and WOx≤3 nanowires. Through X-ray diffraction and X-ray photoelectron spectroscopy, the as-grown tungsten(VI) sub-oxide was identified as monoclinic W18O49. The composite material catalysed the degradation of Rhodamine B at over double the rate of the Ta3N5 nanoparticles alone under illumination by white light, and continued to exhibit superior catalytic properties following recycling of the catalysts. Moreover, strong molecular adsorption of the dye to the W18O49 component of the composite resulted in near-complete decolourisation of the solution prior to light exposure. The radical species involved within the photocatalytic mechanisms were also explored through use of scavenger reagents. Our research demonstrates the exciting potential of this novel photocatalyst for the degradation of organic contaminants, and to the authors’ knowledge the material has not been investigated previously. In addition, the simplicity of the synthesis process indicates that the material is a viable candidate for the scale-up and removal of dye pollutants on a wider scale

Experimental Study and Mathematical Modeling of Propane-SCR-NOx Using Group Method of Data Handling and Artificial Neural Network

In this study, the catalytic behavior of protonated clinoptilolite in propane-SCR-NOx was investigated. The experiments were carried out in the temperature range of 200-500 degrees C as a function of zeolite mesh size 20, 35 and 70 at different weights of zeolite (0.45-1 g) and flow rates (300-600 ml/min) and consequently at various gas hourly space velocities (GHSV). Group method of data handling (GMDH) and artificial neural network (ANN) system were applied for mathematical modeling of NOx conversion to N-2 in propane-SCR-NOx. The operating temperature (T), volumetric flow rate (F) and the weight of clinoptilolite zeolite (W) and the conversion of NOx to N-2 (X) were considered as the inputs and output, respectively. In order to evaluate the models performance, conversions of NOx obtained from the GMDH and ANN systems were compared with those obtained from the experimental method. It is concluded that the ANN could successively estimate the conversion and the results were in a good agreement with the experimental data

Multi-Component Adsorption of Benzene, Toluene, Ethylbenzene, and Xylene from Aqueous Solutions by Montmorillonite Modified with Tetradecyl Trimethyl Ammonium Bromide

Multicomponent adsorption of benzene, toluene, ethylbenzene, and xylene (BTEX) was assessed in aqueous solutions by montmorillonite modified with tetradecyl trimethyl ammonium bromide (TTAB-Mt). Batch experiments were conducted to determine the influences of parameters including loading rates of surfactant, contact time, pH, adsorbate concentration, and temperature on the adsorption efficiency. Scanning electron microscope (SEM) and X-ray diffractometer (XRD) were used to determine the adsorbent properties. Results showed that the modification of the adsorbent via the surfactant causes structural changes of the adsorbent. It was found that the optimum adsorption condition achieves with the surfactant loading rate of 200 of the cation exchange capacity (CEC) of the adsorbent for a period of 24 h. The sorption of BTEX by TTAB-Mt was in the order of B < T < E < X . The experimental data were fitted by many kinetic and isotherm models. The results also showed that the pseudo-second-order kinetic model and Freundlich isotherm model could, respectively, be fitted to the experimental data better than other available kinetic and isotherm models. The thermodynamic study indicated that the sorption of BTEX with TTAB-Mt was achieved spontaneously and the adsorption process was endothermic as well as physical in nature. The regeneration results of the adsorbent also showed that the adsorption capacity of adsorbent after one use was 51 to 70 of original TTAB-Mt

Removal of lindane as a health-toxic pesticide in drinking water by slow sand filtration

Lindane is applied in agriculture as insecticide and in veterinary medicine to control the insect-borne diseases. Contact to this synthetic chemical has various adverse effects on human health. This study was conducted to remove lindane in water by slow sand filtration (SSF). The effects of different parameters including lindane concentration, turbidity, filter bed depth and Schmutzdecke type were assessed on the removal of lindane by SSF. The results indicated that the filter media caused the removal of 85.4, 95.4 and 100 inlet lindane concentration of 200, 100 and 20 mu g/L, respectively, over 1 d after operation. These removal efficiencies were approximately constant by increasing operation period up to 5 d. Water turbidity up to 5 NTU had an insignificant effect on the removal of lindane. The filter depth more than 20 cm had negligible effect on the removal of lindane. The findings also showed that the filter media decreased 98.0 and 98.3 of water turbidity and heterotrophic plate count, respectively. The removal efficiency of lindane by the SSF-modified Schmutzdecke layer was nearly 15 higher than that of SSF with the natural Schmutzdecke layer. On the basis of the results, SSF can meet the WHO guideline for lindane in drinking water only in low concentration (up to 20 mu g/L)

Comparison of advanced oxidation methods of Fenton, UV/Fenton, and O-3/Fenton in treatment of municipal wastewater

The present study aimed to evaluate the efficiency of advanced oxidation methods: Fenton, UV/Fenton, and O-3/Fenton in the treatment of municipal wastewater. The effect of H2O2:Fe2+ ratio, pH, and reaction time on chemical and biological parameters: chemical oxygen demand (COD), biological oxygen demand (BOD5), total coliform (TC), and Fecal coliform (FC) were evaluated in different advanced oxidation processes (AOPs) methods (Fenton, UV/Fenton, and O-3/Fenton). All parameters were measured according to the standards methods. The results obtained from the present study showed that the highest removal of pollutants was achieved in H2O2:Fe2+ mole ratio of 0.7:1. Furthermore, the removal of COD, BOD5 were increased when pH increased from 4 to 7. Moreover, reaction time influenced COD, BOD5, TC, and FC until equilibrium time, however, its influence was not significant after equilibrium value. A comparative study on different AOP systems showed the order of highest to lowest removal efficiency of all parameters is as follows: O-3/H2O2/Fe2+ > UV/H2O2 /Fe2+ > H2O2/Fe2+. It can be concluded that Fenton and its modified methods have the promising potential for advanced municipal wastewater treatment