فهرست مطالب حامد جعفری

The purpose of this study is to investigate the conditions governing a flameless combustion furnace with natural gas fuel. In this article, by changing the arrangement and distances of the four symmetrical air inlets from the central fuel inlet, The concept of eddy dissipation model with coefficient correction has been used to model combustion with reduced chemical kinetics DRM22. Two symmetrical cross arrangements "X" and "+" configuration, were determined to minimize the dead space in the furnace for air inlets. Lower limit of the air and fuel inlet distance was assumed to be 12 mm and the upper limit of this distance was 36 mm in the simulation. Most of all, by examining the combustion parameters, the proposed geometry was selected for the construction of the furnace. The recirculation factor (Kv) has been increased by 2.6 times compared to the base furnace. Also, the maximum temperature has decreased by 5% and the difference between the maximum and average temperature by 77 Kelvin compared to the basic furnace, and this indicates better temperature uniformity. Also, the maximum heat of reaction of specified point in the furnace has increased by 63% compared to the base furnace and indicates the higher potential of the furnace in heat treatment. It is possible to extend results of this research to natural gas industrial furnaces.

In the current study, the competition between two substitutable products is investigated on a supply chain containing two manufacturers and two sellers. In this structure, two substitutable products are made by two competing manufacturers and are then delivered to customers through two competing sellers. One of the manufacturers sells his products with no investment on advertising, whereas another one aims to attract more customers by investing on the advertisement level. In this setting, a cooperative advertising contract is implemented between the manufacturer and seller of the second product in which the seller undertakes a portion of the related investment. Then, the game theory is applied to make the pricing and advertising decisions under the considered problem. Note that in the previous studies, the issue of the cooperative advertising has been considered for a specific product and then the game theory has been used in order to set the decisions among its supply chain members, while in this research, two substitutable products are considered and the effect of implementing a cooperative advertising contract is investigated on their demands and the profit values of their supply chain members. Regarding the results, increasing the elasticity of the demand for a product with respect to its advertisement level leads to enhancing the profits for its members and reducing the profits for the others. Moreover, if the required budget does not exceed a specific value, then investing on the advertisement level of a product is beneficial for its members.

In procedure for analysis, design and optimization of reinforced concrete buildings, for most or maybe all regular buildings, different parts of the procedure for different parts of the building, including main structure and its foundation, are usually carried out independently. This means that these structures are mainly analyzed and designed by supposing a fixed-base, and then, forces at the foot of columns are obtained and used to analyze and design the foundation. Thereby, no attention is paid to the effects of foundation settlements on the distribution of forces in structural elements. Interaction between the structure, the foundation and its subsoil (flexible-base), changes the actual behavior of the structure compared to the method in which the structure is investigated alone (fixed-base). In this paper, various RC buildings, including low-, mid- and high-rise types, with foundations and soil under their foundations in three different layers, with a depth of each layer equal to ten meters, are modeled using SAP2000. Also, all the frames are optimized using Artificial-Bee-Colony algorithm in MATLAB, subject to stress and drift constraints. The results show that, since in a structure with optimal design the values of stress in elements and drift of stories are usually very close to the maximum allowable limits, hence, a slight increase in structural response, induced by soil-structure interaction effects, may lead to the violation of optimal design constraints. Therefore, taking not into account such effects in design optimization of structure, may lead to not only a non-optimal but also an infeasible design.

After the collapse of the Soviet :union:, the Caspian Sea has become a place of competition between newly independent countries, and the quantitative and qualitative increase of modern sea vessels has been one of the actions of these countries. This research is applied in terms of purpose, descriptive in terms of nature, and survey type in terms of the method of collecting and analyzing information. The obtained data has been analyzed in SPSS software platform. The findings of the research show that there is a significant relationship between the level and class of vessels, the quantity and number of vessels, the equipment and facilities of vessels and the improvement of the security of the borders of the Caspian Sea in Mazandaran province. The obtained results show that the Islamic Republic of Iran had the lowest growth rate of military and security expenses in the matter of navigation among the five countries on the shores of the Caspian Sea, while Russia has the best navigation vessels, equipment and facilities and can It should be a good example for the Islamic Republic of Iran in strengthening the buoyancy of the coast guard and the way of controlling and monitoring the Caspian sea borders.

In this research, a recyclable waste is used to manufacture a specific product. For this reason, a supply chain is considered containing manufacturer, recycler, and waste warehouse. First, the customers’ demand for the considered product is determined based on its price. Then, the manufacturer produces it from a waste with specific recyclability rate. The waste warehouse collects the waste and the recycler recycles it. The manufacturer meets his requirements through two different channels. He can procure the non-recycled waste from the waste warehouse and then recycles it himself, or can buy the recycled waste from the recycler. The manufacturer selects these channels based on the established situations.

The game theory is applied to make the decisions under two considered channels. In this setting, a Stackelberg game is developed based on the competitive situation established among the members, where the manufacturer has higher decision power than the waste warehouse and recycler.

Eventually, the given strategies are discussed and the obtained results are presented. Results indicate that the manufacturer selects each channel as a threshold is met. Moreover, more recyclability rate of the considered waste leads to higher profits for the members.

Originality/Value:

 In this research, to provide the waste materials required for producing a product, the game-theoretic approach as well as the concept of the channel-selection are used. It can be stated that this issue has been proposed for the first time in the literature.

The purpose of this paper is to consider products such as disposable tableware produced from plastic waste. In this setting, plastic waste is collected, recycled, and reused. In this research, a supply chain including waste depot, recycler, and manufacturer is considered in which plastic waste is reused in order to manufacture a product. Under this supply chain, the waste depot collects non-recycled plastic waste and the recycler recycles it. Then, the manufacturer uses recycled plastic waste to produce final product and meet customer demand. In this structure, the waste depot, recycler, and manufacturer set the price of non-recycled plastic waste, the price of recycled plastic waste, and the price of final product, respectively.

The game theory is used to make the decisions under the considered supply chain. It is assumed that the decision power of the manufacturer is more than of the waste depot and recycler. In this setting, Stackelberg game-theoretic model is established in order to specify the prices adopted by the members.

Results indicate that decision powers of the waste depot and recycler have no effect on the price and demand of final product. The profits allocated to the manufacturer are the same when decision powers of the waste depot and recycler are different. Moreover, more the price elasticity of the demand for final product leads to lower profits for the members.

Originality/Value: 

Using plastic waste is an effective approach to sustain environment and reduce pollution. In this research, plastic waste is used to produce products such as disposable tableware in a supply chain including manufacturer, recycler and waste depot. The game theory approach is also used to make decisions. To our knowledge, the idea of applying the game theory to use plastic waste in production of products under the considered supply chain has been raised for the first time in the literature.

The purpose of this study was to explain the role of media in developing the personal brand of professional athletes. This research was of mixed method which was done in two stages of qualitative and quantitative. In the qualitative section, purposive sampling method was used for in-depth interviews. 24 in-depth semi-structured interviews were conducted with media professionals and sports marketers, professional athletes and sports fans. The statistical population of this research consisted of all sports media and marketing specialists, professional athletes and sports fans in which 384 people were selected by stratified random sampling method. In order to collect data, a researcher-made questionnaire. To test the hypotheses, Smart PLS software version 3 was used. Based on the results of the qualitative section, the three main themes of illustration and creating a social base, advertising and validation, interaction and communication, along with nine corresponding categories in the field of media function in developing the personal brand of professional athletes were extracted and explained. The results also showed that the proposed model has a good fit and in analyzing the relationship between the main factors, media function (0.807) has a direct positive and significant effect on the development of personal brand of athletes and 0.8% explains its changes. Therefore, it seems that the media with different functions can provide an effective role in developing the personal brand of athletes and the loyalty of their fans.

Building sports brands is not only related to sports products, teams, and leagues but also has a special place among professional athletes. Therefore, the present study aimed to identify the components that play a role in developing the personal brand of professional athletes. This research was exploratory, and its qualitative method was customary content analysis. Twenty-four semi-structured in-depth interviews were conducted with sports management and marketing professionals, well-known athletes, and sports fans who were selected based on purposive sampling. The collected data were analyzed via open and axial coding. The coding validity was also verified by reviewing and controlling the accuracy of the extracted codes and re-coding the interviews by two collaborating experts. Based on the results of role-playing components in the personal brand development of professional athletes in seven main themes including the role of media, the role of government and federations, communication and interaction, social status, team and sport, individual competencies and Professional competencies, and twenty-five corresponding categories were extracted and explained. Athletes have many components in the construction and development of a personal brand that attention to them can play a significant role in generating income for athletes, sports teams, and fan loyalty. Professional athletes can gain a competitive advantage by improving their individual and professional competencies, paying attention to internal and external interactions that differentiate their brand from competitors.

In this study, pricing and retail-servicing decisions are investigated on a dual-channel supply chain including one manufacturer and one retailer. For this reason, the game-theoretic approach is used to make the decisions under both the competitive and cooperative situations in the considered supply chain. Under the competitive situation, the players maximize their profits independently, while under the cooperative situation, the manufacturer and retailer cooperate to maximize the profit of the whole system. A numerical example is presented to illustrate the obtained results. Then, the analysis obtained from the investigated models will be presented. The results indicate that the retailer’s profit increases by increasing the price in the e-tail channel as well as by decreasing the price set by the manufacturer to the retailer. Under the competitive situation, the retail price increases as the retail services increase. The change of the retail price with respect to the retail services is greater than the change of the etail price. Under the cooperative situation, the retail price of the product increases by increasing the retail services. In addition, the change of the retail price with respect to the retail services is higher than the change of the etail price. Finally, a sensitivity analysis is performed on the considered parameters to determine the effect of the change of the parameters on the players’ profits

Nowadays, the health systems consume a significant share of the budget in each country. Hospitals are considered as the largest organizations to provide the healthcare services. Nurses as one of the major portion of hospitals' human resources consume a considerable part of the hospitals' annual budget. From this point of view, the hospitals' managers must arrange the available nurses efficiently. This problem is worsened by the shortage of the available nurses in many countries. In this setting, the Nurse Scheduling Problem (NSP) has received significant attention in recent years. In this problem, the aim is to assign the shifts to the nurses by satisfying the requirements during the planning horizon. Several factors such as hospital managers' policies, labor laws, governmental regulation, and the status of the nurses at the end of the previous planning horizon should be considered for assigning the shifts to the nurses. Several mathematical models and heuristic and meta-heuristic algorithms have been proposed to solve the NSP by considering various assumptions and constraints. In the real-world problems, the good quality solutions can be obtained by considering the uncertainty concepts in the research problem. In this point of view, in the current study, the uncertainty concepts are considered in the nurse scheduling problem. It can be stated that the nurses' preferences for the working shifts cannot be deterministically specified. For this reason, first, a mathematical programming model is developed to maximize the nurses' preferences to work in their favorable shifts. Then, a fuzzy mathematical modeling approach based on the averaging fuzzy operator is proposed to investigate the uncertainty concepts on the nurses' preferences for the working shifts. Then, some random test problems are generated and solved to evaluate the performance of the developed fuzzy model. Regarding the obtained results, it can be stated that high quality schedules are generated by the proposed fuzzy model.

Due to the competition of regional and trans-regional powers, the Caspian Sea has become a tense and unstable environment after the collapse of the Soviet Union. As a result, the region's movement towards militarization and ultimately the military structure of the countries in the region has expanded significantly. Quantitative and qualitative increase in new naval vessels is one of the measures taken by coastal countries. Given this, the purpose of this study is to investigate the impact of the use of new vessels on the security of the Caspian Sea borders. This research is applied in terms of purpose and descriptive-survey in terms of nature. The statistical population of the study is 70 commanders of vessels of Mazandaran province. The sampling method in this study is a whole questionnaire and data collection tool is a questionnaire. The validity of the present questionnaire has been confirmed by obtaining the opinion of elites and experts and the reliability of the questionnaire has been confirmed by Cronbach's alpha test with a coefficient of (0.912). Spss software has been used to analyze and analyze the obtained data. The obtained findings show that the level and class, quantity and number, equipment and facilities of new vessels have a direct impact on the security of the Caspian Sea water borders in Mazandaran province. The results also show that the Islamic Republic of Iran has the lowest growth rate of military and security spending in the Caspian littoral among the five Caspian littoral states, while Russia has the best vessels, equipment and vessels and can be a good model. For the Islamic Republic of Iran, it should be in strengthening the Coast Guard and how to control and monitor the Caspian Sea borders.

Magnesium alloys, with suitable strength, human-like elastic modulus and density, have potential medical applications in the field of biodegradable implant materials. However, one of the most important barriers to clinical applications of magnesium alloys is the rapid corrosion of these alloys in human body fluids. Grain refinement is an effective way to increase the strength and ductility of magnesium alloys and may improve the corrosion resistance of them. Grain refinement due to the thermomechanical process is an effective way to increase the strength and ductility of magnesium alloys and may affect the corrosion resistance of magnesium alloys. Hence, in this study, the effect of thermomechanical process (including warm forging at 250 ˚C and then annealing for 1 hour at 300 ˚C) on the corrosion behaviour of AZ31 magnesium alloy after 1, 4 and 7 days of immersion in a simulated body fluid was investigated at 25 ˚C. To investigate the microstructure of the samples, an optical and scanning electron microscopes were used. The electrochemical polarization and impedance tests were used to evaluate corrosion rate and corrosion resistance, respectively. The microstructure analysis of the samples showed that the thermomechanical process refined the grain and caused the twins to appear. In fact, the recrystallization resulting from the thermomechanical process caused the grain to refine, increasing the grain boundaries, and reducing the dislocations density, which, in turn, prevented corrosion. The results of impedance and polarization tests also showed that the corrosion resistance of AZ31 sample under thermomechanical operation increased after 7 days of immersion and decreased its corrosion rate.

Given the key importance of the bridges in transportation system lifelines and due to their high initial cost, there is a constant need for the study and monitoring of such structures. The FRP composites, due to their special characteristics including high specific modulus, high specific strength, corrosion resistance, low mass density, and modular construction, can be a good alternative for common bridge deck systems. Too much effort is devoted to implement FRP materials as a whole or in part in bridge construction. There have been several different methods of using FRP materials in bridges, including FRP stay-in-place forms for concrete decks and whole FRP bridge decks. Bridges constantly bear moving mass loads while due to technological progress the moving speeds are approaching higher and higher thresholds, so in this study, effects of moving mass on the dynamic response of steel-FRP and steel-concrete bridges are studied and compared. The deck and moving mass inertia substantially affect the dynamic response of the bridge system. To compare the effect of moving mass on both bridge types, at first, the multi layered beam method (MLB) for determining the FRP beam characteristics is reviewed and its applicability on determining the mechanical properties of laminated beams is investigated through comparison of this method results with numerical and experimental data. It is shown that by using the MLB method very good estimates of the mechanical properties of FRP composite can be achieved. Consequently, the problem of moving mass and its governing differential equations is reviewed and the numerical procedure for solving the set of governing PDEs of the moving mass problem is verified against experimental data. Comparing the theoretical results with the experimental data reveals that the presented methodology correctly estimates the dynamic response of beams subjected to moving masses. After setting up the theoretical framework for the moving mass problem on steel-FRP bridges, the effect of moving mass loading on the dynamic response of steel-FRP and steel-concrete bridge systems is investigated. The results indicate that the mass per length and the stiffness of the deck significantly affect the response of the bridge subjected to moving mass. These effects are captured through two different main parameters which characterize the dynamic behavior of beams subjected to moving masses. The first parameter is the Critical Influential Speed (CIS) at which the maximum deflection of deck at certain location happens. The calculated CIS through the aforementioned methodology indicate that the CIS for steel-FRP system is significantly higher than steel-concrete system. The second important parameter which is determined is the Dynamic Amplification Factor (DAF) which is defined as the ratio of maximum dynamics deflection at the midspan of the beam to its static value. The corresponding results of the DAF indicate that the steel-FRP bridges are less influenced by the moving masses than steel-concrete bridges of the same stiffness. It is shown that the values of DAF are lower in the case of steel-FRP bridge. It can be concluded that this will result in lower vibration amplitudes, which will contribute to higher fatigue life of the bridge system. Regarding these results, this system can be advised in the cases of high and ordinary speed transportation.

The aim of this study was to compare spiritual and emotional intelligences of high schooler girls who memorized the Quran and who did not memorize the Quran in the Esfahan in 2016. The study is applied in terms of purpose and causal-comparative in terms of data collection. The study popula-tion was all high school students of the Esfahan city which includes 33,928 students, of whom 800 are the ones who have memorized the Quran. The sample consisted of 90 students (30 students who memorized the Quran and 30 who did not memorize the Quran, and 30 who are beginners) that chosen randomly. Badi et al.’s Spiritual Intelligence questionnaire and Bar-On emotional intelligence ques-tionnaire were applied. The results showed that there were differences in the scores of general and critical thinking among students who memorized the Quran, students who did not memorize the Quran, and the beginners (they were higher in students who memorized the Quran and the beginners). Independence, happiness, reality testing, interpersonal relations, social respon-sibility, and emotional intelligence were higher in students who memorized the Quran.

Organizations have always been trying to create superior customer value in competitive environment via their operating processes. Marketing and sales departments, as two vital units of organizations, play an important role in value creation process. This study examines marketing and sales interaction in domains of information sharing, structural linkage, power orientation and knowledge and analyzes the impact of this interaction on the operating process of value creation. The findings suggest that positive interaction between these departments results in higher productivity, thus creates higher customer value.