رضا قنبری

Leadership talent is one of the important capabilities and abilities for organizational leadership and guiding the organization's forces to achieve goals. Talented leaders play a significant role in the change and transformation of the organization and act dynamically and creatively against environmental changes and transformations and provide the most competitive advantage for the organization. Therefore, recognizing and paying attention to leadership talent and its development plays an important role in the success of the organization. The present research was conducted with the aim of identifying the effective factors on the development of students' leadership talent with a qualitative approach and thematic analysis method. The participants of the current research were 18 experts in the field of leadership and students who were responsible for leadership in scientific and academic organizations and associations, who were selected by snowball sampling. The data collection tool was a semi-structured interview. After analyzing and coding the data, 134 propositions or basic concepts were identified, which were classified into 26 sub-components . Finally, these sub-components were categorized into four main components (personality characteristics, background, organizational and extra- organizational). Universities' attention to the important factors identified in this research can help attract and better develop leadership talents among students.

Vertical transportation technology is essential for constructing tall and medium-rise buildings. Although lifts are a functional component of buildings, their vital nature depends on the continuous and uninterrupted use of lifts in each tall building. Therefore, using lifts for vertical transportation of materials and human resources has gained greater importance. Extensive research has been conducted on reducing lift travel time between floors, optimizing lift systems design, optimizing lift movement paths, determining the sequence of floor travel, managing lift energy consumption, and floor zoning. However, the optimization of lift installation locations and quantities has not been examined so far. The use of lifts in construction projects incurs multiple costs, including rental or purchase costs, energy consumption during vertical transportation of materials, and operator salaries. One of the main solutions to reduce these costs is to minimize the duration of lift usage, which, by delivering the required materials on time, can also reduce the project's execution time. The installation costs of lifts may also vary at different candidate points due to factors such as weight and dimensional capacity, electricity consumption, the number of visits for monthly or annual maintenance and repair, and lift operator salaries. Additionally, some candidate points may have advantages over other points in terms of the amount of horizontal movement of materials on building floors. These distinctive features present challenges in selecting the optimal installation point. In this article, an integer linear programming model has been proposed to determine the optimal number and location of lift installations. The number of lifts used can affect the number of project working days, and as a result, the optimization is performed simultaneously for the number of working days and the number of lifts. The goal of this optimization model is to minimize the duration of lift usage and the associated costs. Additionally, using this model, the number of project working days is obtained with a balanced distribution of lift activities. The effectiveness of the proposed model was tested in a case study to evaluate its effectiveness. The case study involved a 20-story building located in the city of Mashhad, which requires determining the number and location of lifts during the workshop preparation phase. Using this model can lead to cost reduction and a decrease in the number of project working days.

Low-light images often suffer from low brightness and contrast, which makes some scene details hard to see. This can affect the performance of many computer vision tasks, such as object recognition, tracking, scene understanding, and occlusion detection. Therefore, it is important and useful to enhance low-light images. One technique to enhance low-light images is based on the Retinex theory, which decomposes images into two components: reflection and illumination. Several mathematical models have been recently developed to estimate the illumination map using this theory. These methods first compute an initial illumination map and then refine it by solving a mathematical model. This paper introduces a novel method based on the Retinex theory to estimate the illumination map. The proposed method employs a new mathematical model with a differentiable objective function, unlike other similar models. This allows us to use more diverse methods to solve the proposed model, as classical optimization methods such as Newton, Gradient, and Trust-Region methods need the objective function to be differentiable. The proposed model also has linear constraints and is convex, which are desirable properties for optimization. We use the CPLEX solver to solve the proposed model, as it performs well and exploits the features of the model. Finally, we improve the illumination map obtained from the mathematical model using a simple linear transformation. This paper introduces a new method based on the Retinex theory for enhancing low-light images. The proposed method improves the illumination and the visibility of the scene details. We compare the performance of our method with six existing methods AMSR, NPE, SRIE, DONG, MF, and LIME. We use four common metrics to evaluate the visual quality of the enhanced images: AMBE, LOE, SSIM, and NIQE. The results demonstrate that our method is competitive with many of the state-of-the-art methods for low-light image enhancement.

The concepts of stakeholder participation and interaction have been highlighted in science and technology policy literature for about two decades. The research question is "What are the obstacles and mechanisms facing stakeholders' interactions in the science and technology policy making process?". To answer this question, thematic analysis was used. For this purpose, two specialized journals, Research Policy and Science and Public Policy, with the most articles related to the topic of this research, were selected and analyzed. Based on the findings of the research, components such as: differences in views, interests, background and position of stakeholders, restrictive laws and regulations, complexity of Policy and specialization, unbalanced distribution of power, limited policy options, distance between theory And political action, confrontation of values and beliefs with technical issues, wrong timing for participation, political system and limited experience and knowledge of the stakeholders are obstacles to the interactions of the stakeholders. Despite these obstacles, in the analyzed articles, 26 interaction methods were introduced in three general categories: "virtual and face-to-face", "general methods for people and experts" and "direct and indirect interaction methods".

Higher education plays an important and effective role in the education of society's human resources by providing appropriate platforms and opportunities to acquire and develop students' leadership skills. In fact, many higher education institutions consider developing students' leadership skills as an important mission of higher education in order to prepare graduates for future leaders. Therefore, identifying the basic competencies of student leadership is a basic and fundamental step to move towards the professional development of student leadership. The current research was conducted with the aim of identifying students' leadership competencies with a qualitative approach and thematic analysis method. The participants of the current research were 18 experts in the field of leadership and students who were responsible for leadership in scientific and academic organizations and associations, who were selected by snowball sampling. The data collection tool was a semi-structured interview. The interviews continued until theoretical saturation. In order to ensure the validity of the data obtained from the interview, the method of recoding and receiving feedback from the participants was used. After analyzing and coding the data and combining and adjusting the data, 54 main competencies were identified for student leadership competencies. Then the identified competencies were classified into 7 main categories (individual/personality, cognitive, psychological, managerial, interpersonal, technical and moral competencies(. The attention of universities to the development of competencies identified in this research can help to better develop talent and leadership competencies among students.

Self-efficacy, which means people's trust in their abilities and capabilities in critical situations, can be related to life satisfaction, and it is one of the components related to people's health and happiness. This study aimed to determine the relationship between self-efficacy and life satisfaction in pregnant women.

This descriptive and cross-sectional study was carried out in 2021 on 135 pregnant women who were selected randomly. The data collection tool included a checklist of personal-social characteristics of the expectant mother, gestational age, number of pregnancies, and sex of the fetus. The second part included the main variables of the study, i.e., life satisfaction and self-efficacy. Due to the hidden nature of the life satisfaction variable, latent profile analysis was used for optimal classification with the least error. Descriptive analysis, chi-square, and one-way analysis of variance were performed in Stata-16 software, and latent profile analysis by MPLUS 8.3.

The general self-efficacy score of pregnant women had a significant difference based on fetal gender (P=0.0004), number of pregnancies (P=0.04), and gestational age (P=0.002); However, based on the variables of occupation (P=0.667), mother's education (P=0.345), and age group (P=0.439), there was no statistically significant difference. Profiles of life satisfaction based on the variables of fetal sex (P=0.744), number of pregnancies (0.521), gestational age (0.194), occupation (P=0.433), mother's education (P=0.429) and age group (P=0.563) was not statistically significant. In addition, the pregnant women's general self-efficacy score had no statistically significant difference based on the life satisfaction profiles (P=0.152).

Typically, general self-efficacy is not correlated with life satisfaction in pregnant women. Maybe indirect self-efficacy (for example as mediator) can justify this issue.

Groundwater management requires accurate quantitative and qualitative monitoring of groundwater with proper spatial and temporal distribution. Minimizing the number of monitoring wells with maximum spatial distribution for making it economical to monitor groundwater systems is required by managers. Therefore, the structure of groundwater monitoring networks and the number of required wells becomes an engineering optimization problem. The purpose of this study is to find candidates for optimal monitoring network with the least number of wells that provide sufficient coverage to identify groundwater quality in an area. Hence, the excess wells in the network are identified. The meta-heuristic Tabu search algorithm has been used in this research. The objective function in this study consists of two conflicting goals. The first goal is the maximization of the match between the interpolated groundwater quality index distributions obtained using data from all wells and the wells from newly-generated network. The Nash-Sutcliffe model was utilized as a criterion to evaluate this compliance. In this study, groundwater quality is expressed using a water quality index, including nine quality parameters. The second goal is to minimize the number of monitoring wells selected to save on monitoring costs. The two mentioned goals are summed up in a function using a weight coefficient that determines the importance of the goals compared to each other. The mentioned model was used for a number of different active wells. Also, using the Tabu search algorithm, the best combination of different active wells that achieves the maximum objective function was identified. Optimal networks suggest managers and decision makers to choose the optimal network to monitor water quality according to the accepted budget and error. Consequently, this optimizing model could reduce the number of monitoring wells by 34 - 75%.

One of the most important and main concepts in the religion of Islam is Islamic spirituality. Islamic spirituality is in fact the essence and foundation of Islamic civilization. Islamic spirituality considers man worthy and deserving of approaching God and introduces him as having the talent of the divine caliphate and the manifestation of divine names and attributes. The purpose of this study is to identify the characteristics and dimensions of Islamic spirituality for students of medical universities.

The present study is a qualitative study. Semi-structured interview tools were used to collect data. 19 participants in the field of Islamic ethics and spirituality in Tehran University of Medical Sciences participated in the study and were selected by snowball sampling method and interviews were conducted until data saturation. Data analysis was performed by Strauss-Corbin method.

From the analysis of the content of the interviews, 3 main themes of insight, attitude and behavior as dimensions and 21 sub-themes as indicators of Islamic spirituality were obtained.

According to the findings of the present study, educational officials and curriculum planners are recommended to use the benefits of this study in the development of curricula or workshops for students of medical universities.

One of the important components of the internationalization of higher education is recruiting international students.  Despite the small number of international students and due the effects and consequences of their education on the educational systems of different countries, their satisfaction with the quality of university services is important.  Given the importance of this issue, few studies have focused on the evaluation of the quality of university services from the point of view of international students in Iran. Therefore, the purpose of this descriptive survey study was to evaluate the quality of university services from the point of view of international students studying at Shahid Beheshti University. The statistical population was all 221 international students studying at Shahid Beheshti University.  sample size was determined 140 via Krejci & Morgan table. Based on simple random sampling method and Considering the drop coefficient, 150 questionnaires were distributed among students and 126 questionnaires were collected. The instrument was a researcher-made questionnaire. It included 6 components of the quality of university services including educational-research services, library, and media services, administrative services, welfare services, physical spaces, social and cultural services. These 6 components were measured in expectations and real existing levels. To assess the validity of the questionnaire, the opinions of academic experts was used and the reliability of the questionnaire was estimated at 0.96 at the expectations and 0.96 at the existing   levels, using the Cronbach's alpha test. Findings indicated that there is a gap between the expectations and reality (p=0.001). Most gaps between expectations and reality included the quality of administrative services (-1.45) and the quality of educational and research services (-0.73).

Although urbanization brings prosperity and comfort to rural migrants and increases the income and perhaps the socio-economic base of migrants, it may endanger the health of people and their health Issues such as air pollution, noise pollution and urban pollution in general, migration from the village to the city is an inevitable process that takes place with different standards in all countries of the world, including our country, and this has attracted the attention of most urban thinkers. The cultural inconsistencies that immigrants have with the urban population increases the possibility of social deviations .The research method is analytical and it is classified as applied research in terms of the type of research. The statistical population of the research is 10,038 people aged 20-34 from rural areas living in Semiram city, and using Cochran's formula, a sample size of 320 people was selected. The sampling method in this research is random. The findings of the study show that there is a significant relationship between the variables of age, access to facilities and welfare services of villagers, the level of satisfaction with educational facilities, the ease of access to the city and the influence of mass communication tools and the desire to settle in the city.Also, there was no significant relationship between the variables of socio-economic base, gender, distance from the village to the city, and the type of use of mass communication tools and the desire to live in the city.

Given the nature of many development projects, it is necessary to evaluate their effects on human health. Due to the lack of a specific model, the purpose of this study was to provide a tool to prioritize the effects of construction and operation (C&O) of a combined cycle power plants (CCPPs) on physical health.

By reviewing the documents and interviewing 15 experts, the variables affecting physical health in the C&O of the CCPPs were identified. Then, the content validity of the variables was assessed and the enumerated questionnaire was provided to the experts to determine the range, duration, probability, magnitude and extent of health effects using a multiple-choice Likert scale. Finally, with an innovative method, high priority variables were determined to evaluate the physical health effects on individuals.

According to expert’s comments, 480 variables affecting physical health in the C&O of the CCPPs were selected and 41 variables were rejected based on the content validity index. The obtained results showed that diseases attributed to particulate matter (PM2.5 and PM10), SO2 and nitrogen oxide, under normal and emergency conditions, highly contributed to the physical health problems during the construction of CCPPs.

 The method presented in this study is applicable to (1) identifies the factors affecting physical health, (2) determines the range of each physical health- associated factor and (3) prioritizes influencing criteria that might affect human health status during the construction and operation of a combined cycle power plant.

Job satisfaction and related factors are very important in emergency nurses and have a significant impact on their performance. Accordingly, this study aimed at assessing job satisfaction and its related factors in pre-hospital and hospital emergency nurses  at Ahvaz Jundishapur University of Medical Sciences.

This research is a descriptive correlational study that was performed on 170 nurses working in pre-hospital emergency and hospital emergency wards in 2018 using simple random sampling. Data collection was performed by two tools including Wysocki and Kromm standard job satisfaction questionnaire and demographic questionnaire for 3 months. Data were analyzed using SPSS software version 22 using descriptive statistics including frequency and mean analytical statistics including Pearson correlation coefficient tests. A significant level (P <0.05) was considered to examine the relationship between variables.

Finding was revealed that 0.6% of nurses were completely dissatisfied and (84.7%) had moderate satisfaction and (14.7%) had high job satisfaction. Further linear regression analysis showed that the factors that had the most impact on job satisfaction were job nature (88.8%), supervision (71.8%), salary (69.8%), co-worker (67%), working conditions (62.2%) and promotions (60.2%). There was no significant correlation between demographic variables (gender, age, education and work experience) and total job satisfaction.

Due to the fact that in this study the job satisfaction of the majority of emergency nurses was at a moderate level, there is still a long way to go to reach a good and excellent level, so it is recommended to officials and stakeholders to create a suitable atmosphere in the workplace, solve the economic problems of the employees in order to increasing their job satisfaction.

Science and Technology Parks and Growth Centers, as major contributors to the economic development of the regional business enterprises, are committed to provide targeted support for entrepreneurs, improve manufacturing efficiency, and create economic growth in the community. In order to improve the impact of these supports, STPs and incubators periodically evaluate the activities of residents and, after identifying strengths and weaknesses, provide services tailored to each company's individual needs. However, it is worthy to ask, what indicators should the evaluation system include that can reflect a true and more comprehensive picture of the company's condition with presenting the company's core needs to the incubator manager? Therefore, in this research some general models of performance evaluation have been reviewed, and as the benefits of BSC model, especially its compatibility to manufacturing SMEs, this system has been used for the principle of the current study. Then, based on 17 years’ experience of Khorasan Science and Technology Park in unlocking the region's manufacturing potential, and the opinions of experts in other incubators in the country and around the world, 104 critical indicators have been identified in evaluating the manufacturing SMEs. These indicators also were ranked using U Mann Whitney and Friedman statistical tests. The results showed that the "customer and market" is more important than the other three perspectives in BSC model, and "Market research" and "CEO capability and expertise" are the most important indicators and sub-indicators, respectively.

Professional ethics is one of the key issues in the field of treatment and its observance can be the main factor for satisfaction and trust of the medical staff. This study endeavored to investigate the relationship between Islamic spirituality and spiritual health and professional ethics among Internal residents of Universities of Medical Sciences in Tehran.

This study is quantitative descriptive-survey. The population consisted of all Internal residents of Universities of Medical Sciences in Tehran who were selected by cluster sampling method. Data were collected using three researcher-made questionnaires. Their face validity was confirmed. And their reliability was calculated through Cronbachchr('39')s alpha coefficient. Pearson correlation test and structural equations were used for data analysis and PLS software.

The results showed that there is a significant relationship (P=0/001) between Islamic spirituality and spiritual health (β = 0.54), between Islamic spirituality and professional ethics (β = 0.25) as well as between Islamic spirituality and professional ethics with mediating role of spiritual health (β = 0.58).

Considering the findings of this study and the positive and significant relationship between Islamic spirituality and spiritual health with professional ethics, to expand and strengthen professional ethics it is recommended to consider the values of spiritual aspects and principles in medical science curricula.

Among the various maintenance methods the condition monitoring method is a proactive method, because before the failure occurs, the time, place and type of failure can be identified. One of the most important methods of condition monitoring is vibration analysis. In the study, the vibration behavior of rotary machines has been studied and an experimental approach has been used to conclude and achieve the research objectives. In this research, it has been tried to take data from the diesel pump under study that the diesel engine has a power of 200 kW and a working pressure of 14 bar; The working health status of this group of machines should be evaluated This is done with the help of vibration measuring tools. By observing the alarm and critical state according to the standards including API610, the exact type of fault has been determined by means of frequency spectrum analysis.

About 5% to 15% of the general population is affected by subclinical hypothyroidism. This disorder is an important risk factor for cardiovascular disease, which is a major cause of mortality in patients on dialysis. Since the treatment of subclinical hypothyroidism leads to recovery of cardiac muscle plasticity and dyslipidemia, screening is essential.
The present case-control study was performed during autumn of 2016 at Imam Ali Hospital (Bojnurd, North Khorasan Province, Iran) on patients on dialysis. Overall, 47 patients, including 21 subjects with normal serum TSH and Free T4 as the case group and 26 subjects with normal thyroid hormone as the control group, were selected and their Thyroid Stimulating Hormone (TSH), FT3, FT4, iPTH, triglycerides, cholesterol, High Density Lipoprotein (HDL), Low Density Lipoprotein (LDL), and calcium were measured. Chi-square test was used to compare the two groups in terms of gender. Independent t-test was used to compare mean age, body mass index, and other factors. Pearson correlation coefficient was used to examine the relationship between variables.
A significant correlation was observed between the mean BMI (22.3 ± 6.8 kg/m2), Triglyceride (TG) (246 ± 126 mg/dl), and Ca (8.5 ± 1.8 mg/dl), and also there were no significant differences in lipid parameters in the case group (P The findings of the current study showed obesity and triglyceridemia in patients with subclinical hypothyroidism deficiency compared to patients without this problem, also it was indicated that PTH has a correlation with dyslipidemia.

Antibiotic-resistant bacteria and genes enter the environment in different ways. The release of these factors into the environment has increased concerns related to public health. The aim of the study was to evaluate the antibiotic resistance genes (ARGs) in the environmental resources. In this systematic review, the data were extracted from valid sources of information including ScienceDirect, PubMed, Google Scholar and SID. Evaluation and selection of articles were conducted on the basis of the PRISMA checklist. A total of 39 articles were included in the study, which were chosen from a total of 1249 papers. The inclusion criterion was the identification of genes encoding antibiotic resistance against the eight important groups of antibiotics determined by using the PCR technique in the environmental sources including municipal and hospital wastewater treatment plants, animal and agricultural wastes, effluents from treatment plants, natural waters, sediments, and drinking waters. In this study, 113 genes encoding antibiotic resistance to eight groups of antibiotics (beta-lactams, aminoglycosides, tetracyclines, macrolides, sulfonamides, chloramphenicol, glycopeptides and quinolones) were identified in various environments. Antibiotic resistance genes were found in all the investigated environments. The investigation of microorganisms carrying these genes shows that most of the bacteria especially gram-negative bacteria are effective in the acquisition and the dissemination of these pollutants in the environment. Discharging the raw wastewaters and effluents from wastewater treatments acts as major routes in the dissemination of ARGs into environment sources and can pose hazards to public health.

Increment of ovulation rate in farm animals improves reproductive performance through increasing in litter size and fecundity rate. Estrus synchronization or the induction of estrus is a valuable management tool for increasing the pregnancy rate in goats. Stimulation of ovulation using different methods can improves reproduction performance by increasing the proportion of goats having twin ovulations and thereby increase kidding percentage (Khaldari 2008; Rahman et al. 2008). It has been suggested to use new reproductive approaches such as controlling and synchronizing of estrus and using hormones by applied Artificial Insemination (AI) to increase prolificacy leading to gain practical and economical advantages. Recently, Progesterone or its analogues is generally used to synchronize estrous during the breeding and non-breeding season. Administration of gonadotropins such as equine Chorionic Gonadotropin (eCG) after stopping progesterone treatment, causes an increase in rate of ovulation (Lopez-Sebastian et al. 2007). Also using Gonadotropin Releasing Hormone (GnRH) with eCG leads to a raise in ovulation rate and litter size in different goats breed (Akifcam and Kuran 2003). The objective of this study was to improve the reproductive performance using GnRH and eCG administration in breeding season.
Material and The experiment was carried out on 150 mature (2–5 years of age), non-lactating does with a body weight varying between 37 and 39 kg. The current study was performed in the natural breeding season under natural photoperiod environment. Synchronization of estrus was done by inserting intravaginal sponges containing 40 mg flugestone acetate (FGA, Chrono-Gest, Intervet International B.V., Holland) for 16 days. Goats were randomly assigned to three groups. The control group (T1) exposed to Khalkhali bucks without any treatments for mating after sponge removal. Goats in second (T2) and Third (T3) groups were injected intramuscularly 400 IU eCG (Serogonadotropin®, Biowet S.A., Poland) and 400 IU eCG with 50 mg GnRH (Vetocept®, Aboureyhan Co., Karaj, Iran) respectively in sponge removal time. Then the does were mated naturally with Khalkhali bucks. Five fertile Khalkhali bucks were introduced to each group twice a day, starting about 24 h after CIDR withdrawal, and left with them for estrus detection and natural mating. Does were observed continuously for 3 h when bucks were introduced to them and their mating were recorded. The date of birth, numbers of kids born per does and weight of each kid were recorded at kidding time. Reproductive parameters, including pregnancy rate, kidding rate, fecundity rate, twinning rate was determined as well. Blood was sampled from the external jugular vein into heparinized test tubes. The first blood samples were collected before inserting intravaginal sponges, the second, 7 days after inserting sponges and the third, one day after intravaginal sponge withdrawal. Samples were immediately transferred to the lab and centrifuged in the tubes for 15 min at 1000 ×g to separate the plasma. Plasma samples were stored at −20 ◦C for less than 2 months until analyzed for estrogen and progesterone concentrations. All assays were carried out in duplicate. The reproductive parameters were analyzed by ProcGenmod using SAS 9.2 in completelyrandomized design. The means of all reproductive traits were compared by using Chi-Square test. Born weight of kids and hormone concentration data were analyzed using the General Linear Models procedure of SAS and P 0.05) in breeding season. Control group had lower fecundity rate (106%) than the treatment groups (158% and 188 % in second and third groups respectively). Lambing rate in 1 to 3 treatments were calculated 113, 175 and 177% respectively that the treatment groups had higher (P 0.05). There was no significant difference in plasma estrogen and progesterone concentrations between treatments as well (P>0.05). eCG has biological activity of FSH and LH hormones and luteinizing effect of eCG promotes the maturation of follicle that lead to increase the production of estrogen hormone. Estrogen is effective in causing the estrous cycle (Godfery et al. 1997). Results of the current study showed that the injection of 400 IU eCG after sponge removal had no effect on kidding rate and pregnancy rate. But Zaiem et al (1996) observed that the goats treated with eCG had a higher pregnancy rate compared to the control group. Although some studies have reported that administration of eCG can improve the kidding rate and pregnancy rate in breeding season (Kermani Moakhar et al. 2012) as well as non-breeding season (Husein and Ababneh 2008). On the other hand, some studies reported that eCG has negative effects on pregnancy rate (Zeleke et al. 2005; Menchaca and Rubianes 2004). In the current study, treatment with eCG and eCGᩴ increased twinning rate. This result agrees with those reported by Ali et al (2007). Zarkawi et al (1999) reported that using eCG at CIDR withdrawal increased twinning rate from 7% in control group to 30% in treatment group. Also they observed no significant difference in twinning rates for high eCG doses. In another study using eCG in breeding season led to significant increase in twinning rate (61.9% vs 29.2%), lambing rate (86.2% vs 68.6%) and fecundity rate (127.6% vs 71.4%) compared with the control group (Koyuncu and Ozis Altıcekic 2010). These results were similar to the findings in the present study. There was no significant difference in weight of kids at kidding between treatments groups and control and this result shows that weight of kids was not affected by hormones treatments.
In conclusion, using of synthetic hormone caused improvement of reproductive efficiency of Khalkhali goat in breeding season.

Discharging effluents containing heavy metals is very harmful due to accumulative property and non-biodegradability of them. Electrocoagulation, due to easy operation and less chemical consumption, is being considered as a process for removal of heavy metals from aqueous environments.
The aim of the study was to evaluate the effects of variables influencing the removal of cadmium from aqueous environment during electrocoagulation and to develop a model for predicting the results.
This experimental study was performed in a batch electrocoagulation reactor using aluminum electrodes. Direct current was supplied using D.C power supply. Cadmium concentrations were measured using standard methods for the examination of water and wastewater. Response surface methodology and central composite design were used to determine the effects of variables (pH, initial concentration of cadmium, electric current density, reaction time and distance between electrodes) on the removal of cadmium, to design the experiments, to prepare the prediction model for cadmium removal and to optimize the variables.
Findings: The optimal removal efficiency in the conditions of pH; 8.32, current density; 2.965mA/cm2, initial concentration; 65.5 mg/L, reaction time; 54 min and distance between electrodes: 0.723cm was 97.5%. Also R2, Adj.R2 and Pred. R2 were 0.98, 0.97 and 0.96, respectively, which indicates a good fit of the data on quadratic equations. The interactions of all variables were significant in the removal of cadmium by electrocoagulation. The quadratic model is a suitable model for predicting the removal of cadmium using electrocoagulation.
Electrocoagulation equipped with aluminum electrodes has high performances in cadmium removal from aqueous environment. This process can be used in primary or supplementary treatment of industrial wastewater containing this heavy metal.

High concentration of aluminum in drinking water may cause adverse health effects. But adding phosphate compounds after coagulant can reduce the concentrations of residual metals. The aim of this study was to apply phosphate compounds to remove residual aluminum resulting from water coagulation process. In this research، Jar tests were used to investigate residual Al removal by use of phosphate compounds in conventional and enhanced coagulation and to determine its affecting parameters. Phosphate compounds were added during rapid mixing. Dosage of alum in conventional coagulation test was 10 mg/l and the tests were done at different temperatures (i. e. 35، 22، and 5o C) and pHs (i. e. 8. 5، 7. 5، 6. 5، and 5. 5). For enhanced coagulation tests، alum at dosages of 10، 20، 30، 40، and 50 mg/l were applied in different pHs (i. e. 5. 5 and normal pH of water). This research showed that phosphate compounds are effective in reducing residual metals. The maximum removal of residual Al was observed at coagulant dosage of 50 mg/l. Concentration of residual metals in conventional coagulation was different at various pHs. Minimum and maximum concentrations of Al were observed in pHs of 6. 5 and 5. 5، respectively. This study showed that addition of phosphate at rapid mixing stage reduces the residual Al. However، the required dosages of phosphate should be increased at pH=5. 5.