The aim of this study was to develop a model for estimation of major THMs produced as a result of river water disinfection. Experiments were designed for this purpose and different ratios of Cl2 to DOC were created in water samples to which were then added different concentrations of bromide ions. After the incubation period, analyzers were used to measure natural organic compounds, TOC, and DOC in the samples and the data thus obtained were fed into the SPSS software. Moreover, multivariate regression analysis was performed to extract the relevant statistical model. Four different formulas were obtained for predicting the rate of each of the THMs produced. Reaction time and bromide ion concentration were identified as the main factors involved in the production of THMs in the water supply investigated. In addition, the carcinogenicity of THMs in water samples reached its maximum with bromide concentrations between 207 and 246mg/l. The formulas obtained in this study can be used as a simple and accurate tool for the initial estimation of THMs production in different water supplies.

Whilst booster chlorination stations are suggested to resolve the drawback of chlorination at water resources, determination of exact amount of injection is still a problem with respect to FORMATION of THM as disinfection byproduct (DBP) of chlorination. In this paper, a multi-objective genetic algoriTHM is used to optimize both the location of chlorination stations and their schedule with respect to residual chlorine and formed THM which is indirectly estimated by a linear relation based on the amount of chlorine consumed. The objectives are to minimize the total amount of consumed disinfectant and to maximize percent of safety drinking water (SDW) assuming a specific number of disinfectant stations. The results show the increase in the number of stations would lead to both a decrease in DBP and maintenance of residual chlorine in standard limits in many parts of the network. Particularly, distant points with a very long resident time often suffer both residual chlorine less than standard limit and DBP with high concentrations. A maximum amount in which no risk of cancer would occur due to DBP is then determined for each specific number of chlorination stations.

The purpose of this research is to investigate the factors affecting the FORMATION of leading schools, so that it can be used in Iran's education. For this purpose, first, according to the research background and theoretical foundations, a conceptual framework was presented in the field of the components of an efficient and progressive school. Due to the nature of the subject, this research is an applied and developmental research and its method is of a mixed type, and includes quantitative and qualitative methods. According to the obtained inFORMATION, the statistical population is about 3000 people. The sample size is estimated to be 344 people using Morgan's table. Stratified sampling method was used for sampling in this research, and 84 managers and 260 teachers participated in this study. The tool of this research is a researcher-made questionnaire. To analyze the data and answer the research questions, the correlation coefficient test and factor analysis were used. The results of the research showed that the components of management and leadership, research factors, educational factors, human resources, budget and infrastructure, technology and equipment are the main components of the FORMATION of leading schools, and the component of educational factors has the largest contribution.

Introduction: Organic matters enter to drinking water from a variety of sources, but one of the major sources of these compounds in aqueous solution can be decomposed plant and microbial residues. Chlorination is the most common method for water disinfection, the free chlorine in the water reacts with natural organic compounds and form disinfection byproducts. One of the dangerous byproducts is Trihalomethanes (THMs). These compounds are suspected to be carcinogenic for humans.Methods: In this study, 96 samples were taken from 4 points (Mianb Steghlal dam, output Minab water treatment plant, input and output of water treatment plant in Bandar Abbas) within 6 months. Parameters such as TOC, pH, temperature and chlorine residual were measured and used for prediction of THM FORMATION by a methematical model.Results: Results showed that Bandar Abbas drinking water has high TOC and THM FORMATION potential is high. Minimum and maximum of THM was measured 14.78 and 84.86mg/l, respectively. Positive correlation was seen between concentrations of organic carbon and pH with THM FORMATION.Conclusion: Increasing pH and TOC concentration in water, leads to increase of THM FORMATION potential. Bandar Abbas drinking water has high potential to form THM, therefore, it is necessary to consider measures in this field.

Background and Objective: Bordetella pertussis is a gram-negative cocobacilli bacterium and etiologic agent of whooping cough that in recent years, the number of its cases is on the rise. The ability of biofilm production helps this bacterium in interference with host immune system, severity of illness and antibiotic sensitivity. Thus, due to the importance of this factor, in this investigation, we tested the ability of Bordetella pertussis isolates in biofilm FORMATION.Materials and Methods: Nasopharyngeal samples were collected from persons who suspected whooping cough from throughout of Iran from 2014 to 2016 and were transferred to pertussis reference laboratory in Pasteur Institute of Iran. The bacterium in question was isolated by culture so that finally we had 20 positive samples. At the end, we performed in vitro biofilm FORMATION test for isolated strains.Results: All of the 20 clinical samples of Bordetella pertussis which in this study were examined could form biofilm and their final OD became between 0.606 and 1.212, the power of the biofilm made by them was intermediate. Conclusion: Findings of this study was similar to researches conducted by other researchers, which showed the ability of the strains of Bordetella pertussis to form biofilm and to create adverse effects on the host for example antibiotic resistance, illness severity, and so on. Thus, considering the importance of this issue, more and broader researches are needed in this area.