داریوش برزوئی

Increased demand for fossil fuels has led to climate change, global warming, and declining energy reserves. The use of renewable energy, such as solar energy, is a suitable approach to generating electricity and heat. One of the common systems in using solar energy is parabolic collectors, which enable this clean energy by converting the incoming radiation into thermal energy. In the present paper, to assess the potential of climates to make optimal use of solar parabolic collectors, a numerical model was developed in MATLAB software. Then, while validating the model with existing experimental results, the effect of climate change has been studied in four areas: energy, exergy, economy, and environment. For this purpose, five cities: Rasht, Shiraz, Tehran, Abadan, and Sanandaj, have been selected as representatives of Iran's climate and energy efficiency and exergy, the unit cost of energy, and the amount of carbon dioxide produced during the life cycle of the system has been obtained. The results show that Shiraz, with a  Semi-Arid Cool climate and thermal efficiency of 72% and a unit cost of  0. 035 $/ kWh, is the optimal climate in the fields of energy and economy, and Sanandaj with a Humid Continental climate and exergy efficiency of 17. 7% is the optimal climate in the field of exergy. In the environment, Rasht, with a Humid Subtropical Climate, was introduced as the optimal climate.

Diaphragm pressure sensors are used in various industries. Much research has been done to optimize and improve the quality of these sensors. This paper investigates "sensitivity" as a critical variable in diaphragm pressure sensors based on MEMS technology. Aperture geometry is one of the most influential variables in the sensitivity of a diaphragm sphygmomanometer, which in addition to sensitivity, can affect other variables such as operating range, sensor accuracy, dimensions, and even price. To increase the performance and sensitivity of pressure sensors, the sensor aperture was simulated in AbaqusFEA software, and while validating the computational solver, different geometries were evaluated. The results showed that the circular diaphragm has the best performance. Then the effect of corrugations on the surface of the diaphragm was investigated, and different forms of waves were simulated. The results showed that creating a circular wave with a radius of 15 μm at the end of the diaphragm surface increases the sensor's sensitivity by 18%.

The increasing emission of greenhouse gases as the most crucial factor in global warming has made this a global concern in recent years. One concept proposed to better understand the amount of greenhouse gas emissions is the carbon footprint. Carbon footprint is the amount of greenhouse gases produced by a particular product or activity in its simplest definition. Since the power generation industry is one of the most highly emitting sectors, the study of carbon footprint has also become significant. This is primarily because fossil fuels are still the number one energy source for electricity generation, and even coal-fired power plants, which have the highest greenhouse gas emissions, will be the number one source in the coming years. They will still have a high share. Therefore, in the present study, while examining the concept of carbon footprint and its calculation method in the electricity industry, in a case study of South Khorasan province, the carbon footprint from steam and combined cycle gas and diesel power plants has been compared with Tabas coal-fired power plant. The obtained results show that the site's elevation according to the air density can have up to 10% impact the carbon footprint of the combined cycle power plant, and sites with low height should be chosen as much as possible. Also, the carbon footprint of the coal-burning power plant with a value of 968 grams per kilowatt hour is far higher than other fossil power plants with a value of 579 grams per kilowatt hour.

The fuel distribution network in the country has a vital role and is responsible for supplying the fuel chain from the refinery to the consumption stage at the refueling station. Due to the critical role of this network in providing the required fuel to vehicles, estimating the reliability and risk and the amount of unsupplied fuel in it is of particular importance. In this study, with the aim of evaluating the reliability of complex fuel distribution networks, a numerical model based on the route graph method in MATLAB software has been developed, and the fuel distribution network of Damavand city has been studied as a case study by the model. In this regard, first, the existing fuel stations in the city are identified and classified. While forming the general graph of the distribution network and naming its nodes, the communication lines between the stations are drawn according to common standards (supporting and adjacent stations), and the developed algorithm has calculated all the available routes from the source refinery to the destination sites. Finally, with the acquisition of the routes, the final assurance of fuel supply at the destination stations has been obtained. The results show that the fuel station "Velayat Abali " with 94% reliability has the minimum amount, and the fuel station "Besat" with 96% reliability has the maximum amount of reliability in the distribution network. Also, defining the configuration of supporting stations in the distribution network increases the reliability of the system.Introduction Reliability modeling and evaluation in distribution networks, including energy, water, and fuel distribution, has progressed significantly in recent years. The statistics show that water and energy distribution networks have the largest share in the unsupplied energy of subscribers. For example, power distribution networks contribute to consumer blackouts, and water distribution networks make a significant contribution to customer water outages. Energy and fuel networks may suffer from performance and failure due to various external and internal factors. External factors mainly include earthquakes, avalanches, special weather conditions, etc., and internal factors, depending on the type of network, are due to failure of control systems, manpower error and limited useful life of equipment. Due to the importance of maintaining network performance in such situations at the desired level, in recent years, several methods have been proposed to evaluate the performance of complex networks that express network reliability in conditions of uncertainty (critical conditions). Since energy and fuel distribution networks are generally complex systems, it is appropriate to use the concept of network equivalent graphs to simplify them.The primary purpose of this study is to introduce an algorithm to calculate the reliability of fuel distribution networks. Achieving this goal requires considering a range to generalize the proposed model and calculate the final reliability. In this regard, by considering the fuel distribution network in Damavand city as a case study, the final reliability of this network is calculated.

Numerous methods have been developed to calculate system reliability, especially in cases where the system cannot be considered in series. The most prominent methods developed are: conditional probability method, cut method, tree diagram method, logic diagram method, connection matrix method, and path graph method. Due to the appropriate approach of the path graph method and its ability to be developed in the software platform, this method has been used in the present study. In this method, all the paths that connect the system input to its output are considered and the reliability of each path is calculated; In other words, the conditions leading to the successful operation of the system are determined. This method is based on the concept of connection set; A connection set is a non-duplicate path of components, the failure of each of which leads to the failure of the connection set, and if any of the sets are in place, the system will function properly. Each set has a parallel connection with the other sets and its members are in series.

After determining the set of available routes developed by the algorithm and having the reliability of each fuel station, the overall reliability of the network is obtained according to Table 4. Table 4. Calculation of the final reliability of the fuel distribution network in Damavand citySelected route setReliabilityBreakabilityfuel not supplied (liters)Routes leading to station number 50.9402330.0597762988.4Routes leading to station number 60.9550310.0449691798.8Routes leading to station number 70.9581540.0418461673.8Routes leading to station number 80.9611560.0388441942.2  

 The summary of the results is as follows:Regarding the reliability of the fuel supply chain of the fuel station of Abali province, with 94% reliability, it has the minimum value. It is the critical point of the distribution network.Besat fuel station located on the south side of the central area with 96.1% reliability is the most reliable station in the fuel distribution network of Damavand city.The use of support stations and two-way communication between adjacent stations in the fuel supply management method increases the system's reliability.

The stock exchange market, as a representative of the capital market, is one of the essential financial-economic pillars of the country. This market plays an effective role in providing financial and capital resources for the economic growth and development of the country. Among the tasks of the stock market, we can mention the increase of capital, investor services, the index contributing to financial health, and the impact on the economic development. Economic development requires a commitment to long-term investment. The stock market provides longterm capital to crucial sectors of the economy, including business and government. For this reason, stock market indices are often used as an indicator of economic health. This article examines the role of the stock market in economic development and explores the reasons for the lack of capital market development based on savings and stock market indicators. Finally, after reviewing the available indicators and statistics, the main reasons for the lack of development of the capital market are: the attractiveness of investment in banks compared to the capital market, high risk of industrial companies in the stock market, and low return on the capital market (with Taking into account the inflation rate) are counted.

Investigating the history of production and dynamics of growing or collapsing bubbles under various environmental conditions plays an important role in the correct understanding of the process of boiling, evaporation, cavitation, and condensation. In this paper, the rising shape regime the air bubble injected into the water column was studied and simulated using numerical and experimental methods. For this purpose, a column filled with water was used in the laboratory as a host fluid and using the high-speed image recording method, the most important hydrodynamic properties of the bubbles, such as velocity, size, pathway, and other bubble properties were measured. Then, using the computational fluid dynamics and the volume of fluid two-phase flow model, ascent and deformation of the single-bubble injected into a stationary reservoir were investigated and compared with previous and current experimental and numerical results. The result of this validation with a good approximation was in accordance with the reference results and it proved the correctness of the solver's and its settings. Finally, the bubble shape regime was calculated by the non-dimensional numbers of Eötvös and Morton and compared with the numerical simulation and empirical test. The regime obtained from the Clift diagram is a spherical cap regime, which at the same conditions, is in accordance with the bubble shaped regime simulated by numerical and experimental methods and this confirms the validity of the numerical solution.