فهرست مطالب mahsa moradi

In the capital structure, there is a necessity and thematic importance for the scientific expression of the impact of strategy and capital structure on the company's cash flows. Tehran securities and exchange in the period 2013 to 2018, which were extracted and analyzed as a sample by the method of systematic deletion of information of 139 companies. The statistical method used is the combined data method and the regression models were fitted with Eviews software. The results of hypothesis testing show that cost leadership and differentiation strategies have a significant effect on different types of cash flows by considering capital structures.

The purpose of this study was to investigate the relationship between Hexad player styles and Kolb learning styles. The research method was a correlation. The statistical population of the study included all students of Zanjan University in the 2019 academic year, of which 120 people were selected as a sample of research by available sampling method. To measure the variables, the Hexad player style Questionaire (Marczewski, 2016) and learning styles Questionaire (Kolb's,2005) were used. The research data were analyzed using the logistics regression method. The results of data analysis on the relationship between game styles and learning styles indicate that the social player style is predictable by divergent, pragmatic, and convergent learning styles and the direction of the relationship in these three styles is positive: divergent (p = ./05), pragmatic (p =./05) and convergent (p =. /05). Also, the results show that the Diverging learning style significantly predicts achiever player style. The direction of this relationship is negative (p = ./05); That is, people who have a higher achiever player style have a less divergent learning style. Also, the Converging learning style can significantly predict the Disrupter player style. The direction of this relationship is positive so learners who have a convergent learning style also have a Disrupter player style. As a result, the dimensions of learning styles and their components can be a good predictor of game styles.

The amount of bread waste is mainly due to the non-principled and incorrect production. The researchers to improving the technological and sensory characteristics of bread types especially bulk and semi-bulk breads have proposed so different approaches. One of the most important way is application of sourdough in this strategic product. Therefore, the aim of this study was investigation of the possibility of using of wheat, rye and quinoa flour in sourdough preparing during different fermentation periods (4, 8 and 12h) and evaluation of sourdough addition on physicochemical, texture, visual and sensory properties of toast bread in the form of a completely randomized design with factorial arrangement (P≤0.05). Results showed that the lowest pHand the highest amount of moisture, acidity, organic acids (acetic acid and lactic acid), specific volume, porosity and softness of the texture was observed in the toast bread containing sourdough prepared by fermented rye flour for 12 hours. By evaluation of crumb color values the highest L* and a* values in samples containing wheat and quinoa flour, respectively were observed. While, by increasing the fermentation time the L* and a* values increased and decreased respectively. Finally, by evaluation of sensory characteristics, two samples prepared by wheat and rye flour that fermented for 12h had the most acceptability. Therefore, it can be said that in order to producing bulk and semi-bulk breads rye flour can be used while improving nutritional value, it also improves the physicochemical, texture and sensory properties of the final product.

Game-based instruction is one of the methods that encourage exploration among learners. Identifying and incorporating exploratory components should be considered as a principal goal in designing a game that provides exploratory instruction. The present study aims to investigate the exploratory components of an educational game.

A systematic review of the literature was performed in accordance with PRISMA guidelines. Based on the inclusion criteria, a comprehensive search was conducted in Google Scholar, ProQuest, ScienceDirect and Scopus for articles published between 1995-2019. A combination of keywords were used in the search, including ("educational game" OR "serious game" OR "adaptive game") AND ("player type" OR "player style" OR "player modeling" OR "Bartle player style" OR "explorer player"). A manual search was also conducted in Google to identify more literature. Furthermore, out of 1034 articles, 39 were studied in depth.

The obtained components were categorized in six sections, including: educational elements (research, serious game, projectbased activities, test hypotheses, question and answer, role play, simulation), exploratory dynamics (exploration, solving, collecting, and build), mechanics (chance, conflict or challenge, collaboration [negative relationship], prizes upon completion, non-linear space, existence of creative tools, existence of ancillary equipment, guidance, open content, customizability, access to all facilities, different ways to study elements and environment, and puzzle), aesthetics, branch stories and proportionality, exploration-based games (emphasis on the pivotal challenge to success, emphasis on meaningful choices, emphasis on thinking versus physical work, emphasis on longer game sessions, no punishment, emphasis on freedom versus control, emphasis on details versus imagination).

Designers can draw on these components when developing a game that suits the learners’ styles. Analysis of the studies showed that the obtained components could be used in educational game design, and the obtained framework is a useful guide for game designers.

The intensity of competition in business markets is to the extent that even the slightest strategic mistakes will lead to the failure of the organizations. The lack of knowledge and implementation of appropriate competitive strategies in such markets and, on the other hand, the failure to review the effects of these strategies on the types of cash flows in diverse capital structures is no also an exception to this rule. The subject of this study is to design and explain the affectivity model of types of cash flows in a diversified capital structure based on the type of strategy. The present study is an applied one in terms of objective, a quantitative one in terms of data type and a descriptive survey one regarding how to conduct. The statistical population consisted of all companies listed on the Tehran Stock Exchange during 2013 to 2017, among which 139 companies were selected as the sample by systematic elimination method. The statistical method used is the panel data method and fitting the regression models has been conducted using the same data. The results indicated that there is no significant difference between the effect of the differentiation strategy on the cash flow of accounting and cash flows to equity in companies that have a debt-based capital structure with companies whose capital structure is based on equity.

The Instructional design plays a key role in the effectiveness of various educational courses. Studies have shown that the Instructional design is one of the key factors that affect the quality of e-learning courses; however, not enough attention has been paid to the instructional design for designing and implementation of e-learning courses. As a result, we face courses and programs which lack quality. Therefore, exploring the effective components of e-learning designing in the literature and offering an e-learning instructional design for higher education was the purpose of this study. To this end, the study used a systematic review and some keywords related to the instructional design were searched for in scientific databases. After reviewing the articles, 33 studies, conducted between 2015 and 2019, were reviewed. The findings showed that needs analysis, content analysis, learner analysis, instructional principles and strategies, learning environment design, electronic content development, messages design, guidance and support, and assessment and evaluation were the primary components affecting the effectiveness of e-learning. Finally, having reviewed and analyzed the results, examined their relevance to the instructional design, and taken into account the experience of authors in the field of e-learning, a framework was proposed for e-learning instructional design, hoped to be utilized by researchers and e-learning   practitioners.

High volumes of wastewater along with contaminants, such as colloids and dyes are discharged from different industries into the environment. These wastewaters create major problems and serious threats for water resources. Therefore, it is essential to treat such wastewaters and reach the effluent discharge standards. In this regard, chitosan as a coagulant has a comparable performance with other coagulants. Moreover, the addition of chitosan and removal of turbidity probably lead to higher efficiency of nanoparticles in lower dosages which is investigated in the current study. Therefore, the purpose of this study was to investigate the efficiency of chitosan and magnesium oxide (MgO) nanoparticles for the removal of color and turbidity. Synthetic wastewater was prepared by mixing specific amounts of bentonite and direct blue 71 dye in distilled water. After the preparation of different concentrations of color and turbidity, the experiments were conducted with different dosages of chitosan and MgO separately and in combination. The influence of variables such as pH, initial concentration of dye and turbidity, MgO and chitosan dosages on removal efficiency was investigated in this study. According to the results, the highest rate of color and turbidity removal was obtained at 1.5 mg/L chitosan in combination with 1.5 g/L MgO with the efficiency of 97.5%. In addition, the highest removal efficiency was obtained at pH of 7. Due to the need for high doses of MgO in high turbidities, the use of chitosan as a coagulant can be effective in reducing the use of MgO.

Modeling the dispersion of pollutants from factory stacks addresses the problem of matching emissions of a cement plant with the capacity of the environment to avoid affecting the environment and society. The main objective of this study was to simulate the dispersion of carbon monoxide (CO) from the main stack of a cement plant in Doroud, Iran using SCREEN3 software developed by the US Environmental Protection Agency (US EPA).
Four samplings were conducted to measure the concentration of CO in the three-stack flow of a cement factory. The input parameters were those affecting gas dispersion and included CO rate, meteorological parameters, factors associated with the stack, and various factors related to the receptor. All factors were incorporated in the model, and dispersion was modeled by SCREEN3.
Southwesterly winds have been dominant in the past 5 years. According to the results of this study, the highest and the lowest CO levels were estimated by the model in spring and autumn as having maximum amounts of 842.06 and 88.31 μg/m3, respectively, within distances of 526 and 960 m from the cement plant, respectively, at a downwind southwesterly direction from the plant.
Although the maximum predicted CO levels in each of the four seasons were lower than the NAAQS criteria, the simulation results can be used as a base for reducing CO emissions to prevent the potentially significant health and environmental impacts imposed by long-term contact to such emissions.

Background & Aims of the Study: One of the most important pollutants in drinking water, air and soils is heavy metals. It is very harmful for humans and other live organisms. The purpose of this study was the usage of a co-composting process for removal of heavy metals from municipal solid waste and sewage sludge.
This experimental study was a conducted sewage sludge and municipal solid waste. For collection of samples from urban solid waste composting and wastewater treatment plant, a 200 mL polyethylene bottles was used, samples after acidification were stored in a dark place at 4°C temperature until the metals analysis the heavy metals values remaining in the samples was measured by graphite furnace absorption spectrometer method (Varian, SpectrAA 240, Australia). In this study, we used SPSS version 16 for data processing; and they were also analyzed by descriptive statistics.
Result of this study showed that values of C/N in the first, second and third stage compost were 31.7, 27.3 and 41.8, respectively. Based on the result of this study the value of removal of Cd with 9.8 mg kg-1 in first stage and Cr, Cu and Zn with 89, 21 and 87.6 mg kg-1 in third stage were highest treatment.
Our results show that co-composting process between many treatment processes having to be cost effective for heavy metal removal from solid waste and wastewater treatment.

The emergence of any new technology in education gives rise to optimistic predictions of significant advances in learning. One of these technologies is an electronic learning system that often needs extensive hardware and software resources to provide a rich learning environment, that requires a great deal of cost to provide these resources. Cloud computing is the perfect solution for providing these resources at the lowest cost and providing rich services in e-learning. The purpose of this research is to study the technology of cloud computing and its advantages and limitations in order to improve the quality of education and learning. For this purpose, by studying the sources of recent years by library method, first while introducing cloud computing and its various services, its advantages and limitations in e-learning have been taken into account and then its solutions for improving the quality of higher education were studied. In the following, after discussion about mobile cloud services in education, the best model of using these services in e-learning and its success factors have been introduced. Based on the analysis, it was found that the best model for providing such services is hybrid cloud computing model and success factors in this case include the integration of education technology, teacher modeling, creating learning community, selecting Web 2.0 devices and softwares, technological and education support, and building sustainable engagement.

The majority of diseases caused by air pollution, such as asthma and allergies, are caused by pathogenic bacteria, which are transmitted through bioaerosols. Bacteria and fungi are the main sources of hospital infections causing the majority of diseases and cases of mortality. The aim of this study was to determine the ratio of indoor to outdoor fungi concentration, the effect of population density on fungi concentration, and the relationship between indoor and outdoor environments. In this study, 3 stations were assessed; the outdoor environment, general indoor environment, and intensive care units (ICUs) of a hospital affiliated to Ahvaz University of Medical Sciences, Iran. These stations were used for the sampling of airborne fungi from October to December 2010.
The samples were collected over a period of 2 minutes in a flow rate of 28.3 l/minute using a QuickTake 30 air sampling pump. The 3 dominant fungi genera in the sampling stations were Aspergillus, Penicillium, and Cladosporium. The average of total fungi concentration before visiting hours was 365.8 CFU/m which was reduced to 578 CFU/m after visiting hours. The indoor to outdoor ratios in the ICU and internal wards for fungi before visiting hours were 0.36 and 0.68, respectively. However, these ratios in the ICU and internal wards for fungi after visiting hours were 0.78 and 0.99, respectively. Following the visiting hours, the concentration of fungi available indoors was conspicuously higher (even in the wards in which no visitors were allowed (e.g., ICUs). Hence, the amount of indoor fungi was affected by the concentration of outdoor fungi and the number of visitors.

Osteoporosis is one of the chronic diseases of the skeletal system characterized by low bone mineral density. Mouth saliva is made up of complex proteins and ions including calcium, potassium, and sodium. Since calcium is an important component of the skeletal system and exists also in saliva, in this study we examined the relationship between salivary calcium and osteoporosis.
In this analytical cross-sectional study, unstimulated saliva samples were collected from 60 patients with rheumatoid arthritis who had history of steroid use. They were divided into equal groups of osteoporosis, osteopenia, and control. All data were analyzed using ANOVA statistical test in SPSS (v.18).
The average calcium concentration in groups of osteoporosis and osteopenia was 1.7 ± 0.70 and 1.7 ± 0.76, respectively. Also, the average frequency of dry mouth in osteoporosis and osteopenia groups was 5 and 6, respectively. The observed differences were not statistically significant between the groups (P = 0.4).
According to the present study, there is no significant relationship between salivary and serum calcium and osteoporosis caused by treatment with glucocorticoid.

Nowadays, volatile organic compounds (TVOCs) are considered as one of the most well-known air pollutants, especially in the indoor environments. The aim of this study was to measure the amount of TVOCs in indoor and fresh air around the intended kindergartens and investigation the association between indoor and outdoor concentrations.
The measurement was done in four kindergartens in Ahvaz city in five days between 9 to 10 oclock in the morning. Overall, 40 samples were collected.The PhoCheck PID Detector portal device was used for activity sampling in this study. Also, the results were reported by SPSS16 Software and descriptive statistics.
The mean of measured TVOC in the indoor and outdoor air were 50 µg/m3 (SD= ±74) and 495 µg/m3 (SD= ±310) respectively. The analyses conducted by the paired-samples t-test and it indicated that the amount of fresh air is not effective on the indoor environment values.
The measured values in indoor air of these kindergartens depend on internal factors and appropriate ventilation is slightly had been effective.

Osteoporosis is one of the chronic diseases of the skeletal system characterized by low bone mineral density. Mouth saliva is made up of complex proteins and ions including calcium, potassium, and sodium. Since calcium is an important component of the skeletal system and exists also in saliva, in this study we examined the relationship between salivary calcium and osteoporosis.
In this analytical cross-sectional study, unstimulated saliva samples were collected from 60 patients with rheumatoid arthritis who had history of steroid use. They were divided into equal groups of osteoporosis, osteopenia, and control. All data were analyzed using ANOVA statistical test in SPSS (v.18).
The average calcium concentration in groups of osteoporosis and osteopenia was 1.7 ± 0.70 and 1.7 ± 0.76, respectively. Also, the average frequency of dry mouth in osteoporosis and osteopenia groups was 5 and 6, respectively. The observed differences were not statistically significant between the groups (P = 0.4).
According to the present study, there is no significant relationship between salivary and serum calcium and osteoporosis caused by treatment with glucocorticoid.

This research was conducted with the aim of evaluating electronic software quality applied at Allameh Tabataba’i university’s libraries (Pars Azarakhsh software) based on ISO 9126. The survey method was used in this research. The statistic population included all employees and managers of Allameh Tabatabaei university’s libraries were 35 people that 32 employees and managers of Psychology & Educational Sciences, Law and Political Sciences, Literature and Foreign languages colleges and free professional training center were selected by Morgan table and through Cluster sampling. The research instrument was a researcher-made questionnaire that its validity was confirmed by experts and professors and its reliability was calculated by Cronbach's Alfa that its value was 0.72. ​​Descriptive statistic manners (Frequency, Mean and Standard Deviation) and inferential statistic manner (One-sample T test) were used for data analysis. At the end of the research, this achieved result was that there is a straight and significant relationship between Pars Azarakhsh software quality with all six components of ISO 9126 quality evaluation model (maintainability, portability, functionality, reliability, usability and efficiency) and Pars Azarakhsh software is compatible with all six components of ISO 9126.

The aim of this study is comparing the effect of Dick & Carey instructional design model And Bybee instructional design model on students’ motivation and learning. The method of this study is Quasi-experimental and the research plan is pretest-posttest with two groups. The statistical society of this study included all female students in first year of high school in Shiraz. The statistical sample in this study was 54 female students and the available sampling was used. The data collection instrument was Herman's promotion motivation questionnaire and researcher-made learning test and in order to calculate the motivation questionnaire reliability, the Cronbach's Alfa method was used that its value was 0.87 and In order to calculate the reliability of learning test the Kuder Richardson 20 was used with the value of. /73. For data analysis, Covariance statistical test was used and the results showed that there is no difference between the Dick & Carey and Bybee methods in the rate of motivation, but there is a significant difference between Dick & Carey and Bybee methods in rate of learning and the Bybee method is more effective on students learning.

The main purpose of this study was comparing the effect of two teaching methods based on Dick & Carey instructional design model and Gagne instructional design model on motivation and learning in science at the first year high school students. The method of this study is Quasi-experimental research and the research design pretest-posttest with the two groups. The statistical society of this study included all female students of six year primary school who were studying in Shiraz city in the academic year 2013-2014. The statistical sample in this study was 54 female students due to limitation in implement was ran as an available sample. The data collection instrument was Hermans promotion motivation questionnaire and researcher-made learning test. In order to calculate the motivation questionnaire reliability, the Cronbach's Alfa method was used that its value was 0.87. In order to calculate the reliability of learning test the kuder.Richardson 20 was used that its value was 73%. For data analysis, Covariance statistical test was used and the results showed that there is no difference in the rate of motivation between Dick & Carey’s model and Gagne’s model but it was showed that there is a significant difference in rate of learning between the Dick & Carey model and Gagne’s model is more effective on students learning.

Introdouction: Dentinal hypersensitivity (DH) is one of the most painful chronic problems reported in dental offices. Various methods have been applied for the treatment of DH. However, majority of them are either ineffective or last for a short period of time. It has been reported that lasers, particularly Neodymium- doped: Yttrium Aluminum Garnet laser (Nd: YAG), can be helpful in the treatment of this disease. However, systematic reviews have shown that the available evidence for its effectiveness is weak. The aim of this study was to evaluate the Nd: YAG laser-prepared dentine surface with different powers and energies. Fifteen extracted human molars were randomly divided into five groups receiving different powers and energies of Nd:YAG laser (Group A: power: 0.7 W, energy: 70 mJ; Group B: power: 0.9 W, energy: 90 mJ; Group C: power: 1.1 W, energy: 110 mJ; Group D: power: 1.3 W, energy: 130 mJ; and Group E: power: 1.5 W, energy: 150 mJ) in three pulse modes. The surfaces of the specimens were then studied using scanning electron microscopy (SEM). With output power of 0.7 W in single, double and triple radiation modes, sealed dentinal tubules and absence of smear layer were observed. The surfaces prepared by using higher powers of 0.9, 1.1, 1.3, and 1.5 W showed the same features as those prepared with 0.7 W power in single and double pulse modes. In addition, carbonization centers were observed when single pulse mode with power of 1.5 W was employed. All combinations of power and energy tested in this study were found to have produced sealing of the dentinal tubules. However, 0.7 W power in double and triple radiation modes is suggested to be the best option for the clinician, due to having the lowest energy, fewer side effects and lower risk of physical dangers, as well as decreasing the occurrence of unwanted carbonizations. Experimental and clinical studies, especially randomized clinical trials, comparing the effects of Nd: YAG lasers with conventional methods are recommended.

Colored wastewaters are major source of aquatic pollution which will cause considerable impacts to the environment if discharge without treatment. In recent years، Electrocoagulation (EC) process has been attracted a great attention for treatment of industrial wastewaters as an appropriate method. In this study، the efficiency of electrocoagulation process on color removal of natural dyeing wastewater was investigated. This study experimentally was run in a batch electrochemical reactor consisting of a 0. 6 L glass beaker، two anodes and two cathodes. The anodesand the cathodeswere made of aluminumand iron or copper respectively which installed in parallel. In each of test، 400mLof wastewater add into the reactor، then effect of three parameters including the current (50-500mA)، reaction time (5-40 min) and the pH of wastewater (pH=4-8) on process performance were investigated. Theresults showed that optimal conditions for Al/Cu and Al/Fe systems was in 400 mA applied current، pH of 4 and 40 minutes. In these conditions، EC with Al/Cu electrodes were capableto remove of almost complete color (98%) and efficiency of COD removal was 28 %، whereas EC with Al/Fe resulted in 97% color removal and 21% COD reduction. Electrical energy consumption and current efficiency of EC process for optimal condition werefound 2. 9kWhm-3 and 110% respectively. According to our finding،it proposed that EC process is very efficient and economic process for color removalfrom wastewater.

Background and Indirect electro-oxidation method with H2O2 electrogeneration is an electrochemical process for wastewater treatment based on the production of hydroxyl radicals by means of H2O2 generation in the presence of transition metals such as copper. The electrogenerated hydrogen peroxide process was performed in an open and undivided cell to be assessed for degradation of real textile wastewater using graphite felt (cathode) and Pt (anode) in the presence of copper ions. The effect of major parameters such as dissolved oxygen concentration, initial pH, applied current, copper concentration and time reaction on the decolorization was investigated. 67.9% decolorization and 56.3% chemical oxygen demand (COD) removal were achieved after 210 minutes reaction under the conditions 7.8-7.9 mg/l dissolved oxygen, 250 mA applied current, 7 mM copper concentration and pH=4. The electrogenrated H2O2 process in presence of copper ions could degrade real textile wastewater. Moreover, due to generation of hydrogen peroxide, this process can be economically important.

Today, there is attention on new and active methods in learning. The emphasis of active methods is to engaging students with real-life issues that are related on Life. Bybee teaching method is one of the new and active teaching methods. The main purpose of this study was to compare the effects of Bybee (5E) and traditional teaching methods on creativity and learning of Third year students in science class. The research method of this study was Quasi-experimental research and the research design pre-test-post-test with control group and the experimental group. The statistical population included all female of third year junior high school students who were studying in Qazvin city in the academic year of 2011-2012. The statistical sample in this study was 61 female students. Due to limitation in implementation, an available sample method was adopted In order to select our sample a school was selected from which two classes Ancova and T test were used for data analysis. Result (s): The results showed that the Bybee’s (5E) teaching method influenced on students’ learning and creativity and confirmed the research hypothesis. New teaching methods development a personal connection between students and the topic of study and it helps students think in a less personally biased way. So, Bybee’s model is a good model for learners to achieve a deep understanding of the subject and increase divergent thinking.

Electro-Fenton process has been widely applied for dye removal from aqueous solution lately. Fenton's reagent is formed in the electrolysis medium through the simultaneous electrochemical reduction of O2 and Fe3+ to H2O2 and Fe2+ respectively on the cathode surface. In this paper, COD reduction potential and decolorization of real textile wastewater were evaluated by electrochemically generated Fenton reagent process. This wastewater mainly contains non-biodegradable acidic dyes, which are highly resistant against conventional oxidizing agents. Electro-Fenton process was carried out in an open and undivided cell in order to evaluate the removal of color and COD from real textile wastewater using graphite felt (cathode) and Pt plate (anode) at room temperature. The effects of current density, flow rate of air, electrolysis time, initial pH, and ferrous ion concentration were investigated for real textile wastewater. The results showed that the optimal experimental conditions obtained in electrochemical studies were as follows: current density=4.8 mA cm-2, pH=3, flow rate of air=1.5L/min, Fe2+=3mM and reaction time=160 min. Under these conditions, COD removal and decolorization achieved were 63% and 77.2% respectively. According to the results achieved, electro-Fenton process can be used as a pretreatment for degradation of colored wastewater and refractory pollutants. Moreover, this feasible technology improves biodegradability of the textile wastewater.