MIlad Mojtahedi

  High-entropy alloys (HEAs), as advanced multicomponent systems comprising at least five principal elements with atomic concentrations ranging from 5 to 35%, have garnered significant attention in engineering research due to their outstanding mechanical, chemical, and thermodynamic properties. Although the fabrication of these alloys has predominantly been investigated in bulk form, limited studies have explored their synthesis as thin-film coatings. In this study, a CoCrNiCuZn high-entropy alloy coating was synthesized via direct current (DC) electrochemical deposition in a chloride-based electrolyte onto a 304 stainless steel substrate. The deposition parameters were systematically examined to analyze the coating’s morphology, chemical composition, and crystallographic structure. Characterization was performed using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and grazing incidence X-ray diffraction (GIXRD). The results indicated that under constant current conditions, the synthesized coating exhibited a smooth, dense, and crack-free surface. Thermodynamic calculations using the HEAPS software predicted the formation of a solid solution phase with a face-centered cubic (FCC) structure, which was consistent with the GIXRD data. The agreement between experimental observations and thermodynamic predictions validated the accuracy of the modeling approach. Corrosion resistance evaluation revealed that the CoCrNiCuZn coating possessed favorable anti-corrosive properties. The sample with a corrosion current density of 3.07 µA/cm² and a corrosion rate of 1.31 mpy was identified as optimal, whereas the sample with a corrosion rate of 23.99 mpy demonstrated inferior performance. The formation of a passive Cr?O? oxide layer by chromium, the stabilizing effect of nickel, and the presence of copper oxides (Cu?O) in the synthesized coating contributed to the mitigation of pitting and galvanic corrosion. Moreover, the homogeneous elemental distribution within the HEA structure reduced susceptibility to intergranular corrosion. The antibacterial properties of the synthesized coating were also investigated. The results demonstrated that leveraging the synergistic effects of the high-entropy alloy enabled exceptional antibacterial efficacy against planktonic bacteria and biofilms, achieved through the integration of antibacterial elements into the final CoCrNiCuZn coating. This study enhanced the antibacterial performance of HEAs through advanced fabrication techniques and assessed their feasibility as biomedical and corrosion-resistant materials with antibacterial functionality. Overall, this research presents a one-step, scalable, and cost-effective approach for synthesizing nanocrystalline HEA coatings, offering substantial potential for industrial and academic applications in materials science and metallurgy.

   Abstract   The Beyglar Beygi Mansion is a historically significant structure from the Qajar era. It was constructed in 1276 AH (1859 AD) in the Feyzabad neighborhood of Kermanshah. Between 1311 and 1315 AH (1893-1897 AD), the mansion underwent expansions, during which the Takyeh was added to the original structure. In 1326 AH (1908 AD), intricate plasterwork and mirror decorations were incorporated. Today, the mansion serves as the Museum of Calligraphy and the Zagros Paleolithic Museum. Recent seismic events in Kermanshah province, especially the Sarpol-e-Zahab earthquake on November 21, 2017, have highlighted the need for a comprehensive seismic assessment of this historic monument. This study aims to evaluate the seismic response of the Beyglar Beygi Mansion and Takyeh under design-level earthquake conditions. A finite element model of the structure was developed using ABAQUS software, which incorporated validated material properties and geometric characteristics based on frequency analyses and historical documentation. The results indicate that the numerical model accurately represents the existing structural conditions. The findings reveal that the structure maintains stability under gravity loads, despite localized weaknesses in the masonry piers and brick components. Additionally, dynamic time-history analyses were conducted using acceleration time history records from the 2017 Sarpol-e-Zahab earthquake in Kermanshah. The modelled damage patterns were compared with observed structural damage to validate the analytical results. Seismic behavior was analyzed using one scaled ground motions that represented the design of the earthquake. The results highlight that the western and northern facades are particularly susceptible to seismic loads, with maximum displacements of up to 70 mm observed in these regions. Such vulnerabilities could lead to localized failure and progressive damage accumulation during future seismic events. Ultimately, this study identifies the critical weak points and seismic response characteristics of the Beyglar Beygi Mansion and Tekyeh, providing valuable insights for future conservation and retrofitting strategies. Keywords: Beyglar Beygi Mansion and Takyeh, Historical Structures, Nonlinear Dynamic Analysis, Seismic Vulnerability, Kermanshah.

   In recent years, fluidized beds have garnered attention across various industries due to their advantageous characteristics, such as uniform temperature distribution, effective phase mixing, and high heat transfer rates. One effective method to enhance the efficiency of these beds is the use of a pulsed inlet. This technique improves the homogeneity of the bed and eliminates inactive and stagnant zones (dead zones) within the particles by varying the inlet air flow. Despite extensive research on the simulation of conventional fluidized beds, the study of pulsed bed systems has been relatively limited. In this thesis, the gas-particle two-phase flow in a spouted fluidized bed with a rectangular geometry and pulsed air inflow was numerically investigated. The simulation was carried out using a combination of Computational Fluid Dynamics (CFD) and the Discrete Element Method (DEM). To reduce computational costs, the geometry was defined as quasi-two-dimensional with a depth of 6 particles. The modeling was performed in a transient state, where a specific number of particles were initially placed at a certain height within the bed, and then gas was injected into the bed at a specified pulsed velocity. In this study, the pulses were applied in three waveforms: square, sinusoidal, and sawtooth, with frequencies of 1, 4, and 10 Hz. The results showed that when fluidizing (side) gases were present in the bed, applying a pulsed inlet in the spout positively impacted the elimination of dead zones and the circulation of particles across all three frequencies and waveforms. It was demonstrated that a frequency of 10 Hz and a square waveform yielded the best results. For instance, in a spouted fluidized bed at 10 Hz, the particle travel distance improved by 12.81%, 5.99%, and 5.97% for square, sinusoidal, and sawtooth waveforms, respectively. Similarly, improvements of 55%, 35%, and 30% were observed in the reduction of dead zones. In rectangular beds, it was found that the removal of fluidizing gases had significant negative effects on particle circulation and increased the dead zones, with the proportion of dead zones rising from 0.5% to 7.7% of the total particles. Finally, to examine the effect of fluidizing gases, different configurations with varying spout and fluidizing gas velocities were investigated. In these configurations, the spout velocity was gradually decreased while simultaneously increasing the fluidizing gas velocity, keeping the total inlet gas flow constant. The results showed that in two configurations where the fluidizing gas velocity reached its maximum, the dead zones were completely eliminated, particle mixing improved, and homogeneity in particle distribution increased. In the optimal gas inlet configuration, applying a square pulsed inlet at 10 Hz resulted in a 1.55% improvement in the average particle travel distance. In this study, it was demonstrated that by applying a pulsed flow and adjusting the inlet gas velocities, the hydrodynamic performance of the bed can be improved without the need for changes in the system geometry or the total inlet flow rate.

      Abstract The present study investigates and analyzes the energy and exergy of solar desiccant cooling systems with the aim of providing thermal comfort in residential buildings with high internal loads in three cities: Ahvaz, Bushehr, and Rasht. Considering the increasing energy demand in buildings and the environmental challenges arising from the consumption of fossil fuels, the use of innovative and sustainable systems in air conditioning has become more important than ever. Accordingly, desiccant cooling systems, which operate based on moisture absorption, have been introduced as an efficient solution for optimizing energy consumption and reducing environmental impacts. The results indicate the high potential of desiccant cooling systems. In this research, a maximum COP (Coefficient of Performance) of 0.404 was recorded for the system at temperatures of 15°C. Additionally, at temperatures of 35°C and 45°C, the COP decreased to 0.32 and 0.33, respectively, indicating better performance of this system at lower temperatures. The analyses also emphasize that the cooling capacity at temperatures ranging from 28°C to 40°C in Bushehr varies between 18.2 to 20.6 kW, and in Ahvaz between 19.5 to 21.5 kW. This research, while providing a roadmap for selecting optimal design parameters, hopes to offer practical solutions for ensuring thermal comfort in hot and humid regions. Overall, the results suggest improved performance of air conditioning systems and achieving thermal comfort in residential buildings through the use of desiccant materials and solar energy. Key words: Solar Desiccant Cooling, Thermal Comfort, Energy and Exergy Analysis, Residential Buildings, Hot and Humid Climates   

  One of the most important sources of energy for the

Nowadays, in order to improve the features and flexibility of DC microgrids, energy storage systems, generation sources, and various loads are connected to each other through bidirectional isolated DC-DC converters for better integration and power exchange between the buses. The Dual Active Bridge (DAB) converter, which is considered an engineering masterpiece among isolated converters, has attracted significant attention due to its numerous advantages such as bidirectional operation, high voltage capability, galvanic isolation, buck-boost functionality, and high efficiency resulting from soft switching. In recent years, the performance of this converter has improved based on different control modulations, including traditional methods such as Single-Phase Shift (  ) and Extended Phase Shift (EPS), which researchers have studied Conventional approaches for modeling these types of converters pose significant challenges and difficulties. DAB converter modulation is an interesting part of ??research, as traditional modulations have significant limitations such as restricted switching regions. Therefore, to overcome these limitations, dual phase shift (DPS) and hybrid phase shift (HPS) modulations have been introduced. Furthermore, another aspect of the efficiency of the DAB converter lies in its ability to connect to various systems, including energy storage devices In explaining the mentioned modulations, operational waveforms are first analyzed for different switching conditions, followed by a control strategy for achieving the desired power transfer. In this thesis, after studying the details of the previous phase shift modulations and presenting new modeling techniques and closed-loop control for the converter, the design process has been thoroughly analyzed in the software environment (Matlab/Simulink). Also, the specifications, design of parameters and the equivalent circuit of the DAB converter have been completely described and different scenarios have been performed in the simulation and obtaining its results. The comparison of the modulations in terms of efficiency, common mode voltages, and zero voltage switching area confirms the accuracy and correctness of the theoretical contents. The simulation results show the success of the control modulations in power transmission operations by the DAB converter. As a result, the DAB converter has a suitable performance for placement in the DC microgrid simulator system. Keywords: Dual Active Bridge (DAB), Phase Shift Modulation, DC Microgrid, Energy Storage Systems, Closed Loop Control,   , EPS, DPS, HPS.   

One of the most important problems of oil reservoirs is damage to the formation, which occurs due to induced and natural factors. The most common method to repair the damage to the formation and increase the productivity of the well is acidizing. Among the important acids for matrix acidification in carbonate tanks, he mentioned organic and inorganic acids, especially hydrochloric acid. In some oil fields, such as the Azar oil field, due to the high temperature and pressure in the drilled well, the speed of acid reaction with the reservoir rock increases, which in turn causes the intensification of sludge generation. Failure to create wormholes. In addition, acids based on hydrochloric acid cause corrosion in the wall pipes of wells. One of the ways to control the reaction kinetics is the use of hybrid acids. Citric acid as an effective organic acid as well as glutamic acid as a chelating acid along with pure hydrochloric acid can be used in acidification of oil fields. Due to their reversibility and low dissociation constant, these acids reduce the reaction rate of acids and are less corrosive and anticorrosive than mineral acids. The purpose of this research is to investigate the effect of hydrochloric-citric acid mixture as well as hydrochloric-glutamic acid on carbonate rock samples and compare it with pure hydrochloric acid, as well as to investigate the changes in the concentration and speed of the impact time of these three types of carbonate acid. In this research, the purpose of measuring the concentration The optimal combination of hydrochloric acid-citric acid-hydrochloric acid-glutamic acid is high temperature in Azar field oil reservoirs. The design of the experiment is by RSM method with two concentration factors of hydrochloric acid and citric acid, respectively, at two levels of 5-15 for hydrochloric acid, two levels of 10-5 for citric acid, and also 8.5% of glutamic acid. It has been used. The method of kinetic calculations based on determining the concentration of the reactant (H+) by the tetration method has been used. In this research, in order to achieve the best concentration of hybrid acid, the qualitative analysis of the results obtained from the experiments was used, and the concentration of 10% hydrochloric acid, 7.5% citric acid, and 8.5% glutamic acid was chosen as the best and most optimal concentration of hybrid acid. It has been achieved. At the end, kinetic experiments were performed at three temperatures of 80, 60 and 40 degrees Celsius on acids with concentrations of 10% citric - 7.5% hydrochloric and 10% glutamic - 8.5% hydrochloric acid with the sample stone until the parameters of the reaction weight. Calculate. The obtained results showed that two separate reactions took place, in the first phase of the reaction, the predominant acid was hydrochloric acid, and in the second stage, the dominant mechanism was with citric acid or glutamic acid.   

The bending frame is one of the favorite lateral load systems of structural designers due to high redundancy. This type of lateral bearing system shows good ductility and energy dissipation. In recent years, progressive damage in various structures has caused irreparable financial and human losses, and the increase in such damage in the structure has led structural engineers to know and deal with such damage. after the 1994 Northridge and 1995 Kobe earthquakes, several studies were conducted on the seismic performance of beam-to-column connections and two general approaches to improve the seismic performance of connections emerged. Strengthening the connection of the beam to the column and weakening the cross section of the beam. By weakening the cross section of the beam, a part of the cross section of the beam near the connection to the column is reduced, and the potential for the formation of a plastic hinge is placed in that place. Weakening the beam cross-section is more economical than strengthening the connection and prevents failures such as weld failure at the beam-to-column connection, which was seen abundantly in the Northridge earthquake. this study ; for improve the performance of steel bending frames with RBS connections after the sudden removal of the column in During progressive failure, A new model has been presented by using a curved steel piece under the title of quarter-circle element. Validation of the laboratory sample has been done in Abaqus 2022 software, and in order to see the effectiveness of the proposed model, we will do parametric studies on the influence of the outer radius, thickness and width of the quarter-circle element. The results of the studies indicate that the proposed model has a positive effect on the strength and ductility of the connection and does not prevent the formation of a plastic hinge in the place of the reduced section of the beam.   

In order to increase the reliability in supplying the energy needed by consumers, plans have been proposed regarding the behavior of resources connected to the power grid in recent years, which are called microgrids. Microgrid systems are formed by the combination of several energy production and storage systems and local consumers. These structures have recently attracted attention all over the world, because these networks can work both connected to the national network and independently or in islands, and they can also cover rural consumers or consumers far from the main network. put A large part of the production of these networks is made up of renewable energy sources such as wind turbines and solar panels. Due to the environmental problems and global warming as well as the energy crisis of the last few decades and the movement of governments towards not depending on fossil fuels, the distribution systems have faced an increase in the penetration of scattered productions based on renewable sources such as wind and solar sources. One of the important factors that affects the performance of the microgrid is the uncertainties in its various parts and components. Various uncertainties such as load uncertainty, DG availability, etc., make the management of this network a serious challenge. With the high penetration of DGs based on renewable energies in the microgrid and the dependence of the production power of these sources on weather conditions, the operation of the microgrid has faced serious uncertainty. The presence of these uncertainties has jeopardized the security of system operation. Providing an effective and efficient solution for the safe operation of future distribution systems in conditions of uncertainty is a necessary and necessary thing. One of the main solutions for this purpose is to use an energy storage system, especially batteries, as a supplement for distributed production, especially production based on renewable energy. In addition to maintaining stability, batteries can make the microgrid a more economical option with ESS when the price of electricity is cheap or there is excess production of local resources. In addition to all these advantages, the investment cost of batteries is high and its technologies are improving and introducing new types every year. Due to the relatively low life span of these equipments, along with the cost factor, the life span is also considered as one of the most important factors for choosing batteries. Therefore, choosing the optimal number and place to install batteries, along with the type of technology chosen, is one of the most important challenges for power grid planners. In the proposed plan, a comprehensive and uncertainty-based model is presented to determine the capacity and optimal location of ESS installation in the microgrid with the penetration of renewable energy-based productions. The proposed model also evaluates the type of battery storage source technology. In other words, the proposed structure is proposed based on conventional and widely used battery models, and the effect of these technologies on the location and total cost of the microgrid is evaluated.  

  Separation of theethylene/ethane mixture by the cryogenic distillation method is a process withsignificant energy consumption and high operating and capital costs due to theclose boiling point of the components and their low relative volatility and similarmolecule sizes. Reducing these costs and lowering energy consumption requiresan efficient separation procedure, and adsorption separation is a promisingenergy-efficient process for ethylene/ethane separation among the separationmethods. In order to use the adsorption separation process successfully,providing an adsorbent that can perform separation at low pressures andtemperatures near ambient is a necessity.The Cu-MOF-74 metal-organicframework is utilized as an adsorbent in this research to separate ethylene andethane. Because of the open metal sites, this framework is favorable for theformation of complexes with unsaturated hydrocarbons (ethylene). One of thepurposes of this research is to investigate and measure ethylene and ethaneadsorption at 278, 298, 313, and 353 K temperatures and to provide the isothermparameters. Additionally, the conventional methods of synthesis oforganic-metallic frameworks have been investigated, and the mechano-chemicalsynthesis method was chosen to synthesize this MOF. Prior to that, wedeveloped, evaluated, and reported scalable techniques for synthesis inindustrial production for them, as well as optimized their operating parametersdue to the unavailability of some of the required raw materials and theexpensive cost of some due to their rarities.Disodium hydroquinone saltwas synthesized using water as a solvent, and an effective approach forproducing it in the industry with a high yield was provided. In contrast toearlier techniques, this one is carried out at room temperature and pressure anddoesn't require the use of hazardous, expensive, or hazardous solvents. The2,5-dihydroxyterephthalic acid (DHTA) ligand was subsequently synthesized usingthis compound, and the DHTA synthesis's operational parameters have beenoptimized. These parameters, which were used to synthesize the chemical with an83% concentration, are temperature (200 ?), pressure (10 bar), the molar ratioof the catalyst to the reactant (2.085), and the reaction time (4.18 hours).Finally, the synthesized DHTA was used to produce Cu-MOF-74 adsorbent. Themaximum amount of adsorption for ethylene and ethane, respectively, was 7.33and 5.26 mmol/g, determined by measuring the amount of adsorption at 278 K. Theamount of adsorption and selectivity decreased and increased, respectively,with increasing temperature. The maximum selectivity occurred at 313 K, andethylene was adsorbed more than twice as much as ethane.

  هدف،

   Currently, removing sulfur from gas or liquid fuels is one of the most important tasks of the oil refining industry. Sulfur compounds such as mercaptans, thiophenes, benzothiophenes, and dibenzothiophenes can be converted into SOx during gas or liquid combustion. Various physical, chemical and biological methods have been investigated in order to remove sulfur impurities from petroleum compounds, which include HDS, ADS, BDS, EDS and ODS. In this research, the oxidative desulfurization process of simulated oil cut containing 1000ppm di-benzothiophene using heterogeneous catalysts with loading of potassium tungsten oxide based on natural kaolin zeolite along with hydrogen peroxide as oxidizing agent and acetonitrile as solvent. The extraction was done in which catalysts with 5, 10, 15, 20% by weight of potassium tungstate based on metakaolin were made by dry inoculation method. After testing the %W catalyst /metaKaolin 15 was chosen as the best catalyst in this research . Then, using Design Expert version 11 software, the experiments were designed and the optimal operating conditions (t=60min, T=60Co, O/S=12, cat=0.04g) were determined and the amount of desulfurization from the model oil in these conditions 98.9% was obtained. Also, the corresponding catalyst still had an acceptable performance after five recovery steps.

  In this research, the effects of sandblasting variables, including mesh size, pressure, distance and time of particle spraying, on the hydrophilicity and roughness of titanium samples were investigated. For this purpose, the desired surface properties were obtained by cleaning the samples through two-step acid washing. After each step, the samples were tested in terms of roughness and hydrophilicity. Also, the surface morphology of the samples was analyzed by scanning electron microscopy (FESEM) in order to determine the best acid washing time. Various biological tests including cell culture, cell toxicity, antibacterial, and protein adsorption were also performed on the samples. SEM images obtained from the sandblasted samples showed that increasing the acid washing time from 5 min to 10 min in the second acid solution results in a rough titanium surface with smaller surface pores. In order to enhance the hydrophilicity of the surface and thus, to reduce the stabilization time of the implants in the dental cavity, the samples were exposed to various surface treatments such as nitrogen plasma, liquid nitrogen washing, visible light irradiation, and hydrothermal treatment. Then the samples were stored in 5X    solution in nitrogen atmosphere for 5 months. After that, hydrophilicity, protein absorption, cell culture, MTT, and antibacterial tests were performed on the samples. XRD analysis performed after hydrothermal treatment also showed that the structure of titanium has changed to anatase phase. Hydrophilicity tests showed that the wetting angle of all the samples is less than 10?. Therefore, it can be concluded that superhydrophilic properties have been achieved in all the titanium samples. Nitrogen plasma and hydrothermal treatment showed the most effect on the superhydrophilic properties. In addition, the highest protein adsorption (0.110) and cell adhesion was achieved after hydrothermal treatment. The results of antibacterial test also showed that surface activation methods have no significant effect on antibacterial properties.

Purpose: Tailings dams that are built in mines and processing plants are hydraulic structures for collecting and storing waste materials in the form of effluents and waste materials from the concentration process in processing plants and minerals. The discharge of sewage and waste materials stored in the dam due to the leakage or failure of the dam creates an important environmental environment in the region, and its entry into surface water, underground and soil causes irreparable damage to the environment and human life. . comes with Due to the inefficiency of tailings dams, less attention is paid to their proper design and construction, which breaks 2.5 times more than water dams. Waste materials in dams may have a longitudinal slope or both longitudinal and transverse slopes. In this project, an attempt has been made to investigate the effects of the longitudinal slope and the combined lateral and longitudinal slope of the bed on the volume of output material and the shape of the eroded bed. Methodology: Due to the fact that the way waste material is placed in the reservoir of the dam may have an effect on the appearance of the eroded bed and the volume of material removed due to failure. A laboratory study should be done in this case. In this research, in order to investigate the effect of longitudinal slope and combined lateral and longitudinal slope of the bed on the volume of output material and the shape of the eroded bed at the end of the experiment, scans of the topography of the eroded bed were prepared. According to bed topography scans, the volume of output material and the shape of scour hole have been investigated. Findings: When the slope of the bed in tailings is only a longitudinal slope, the volume of removed material has decreased by 8.3% compared to the largest volume of material removed in the case of both longitudinal and transverse slope. Also, the development of the eroded cavity along the width of the reservoir or the dam body during the longitudinal slope of the tailings material is about 12 times the width of the failure. While this amount is about 5 to 6 times in both longitudinal and transverse slopes. Result: When tailings have only a longitudinal slope, the development of the scour hole is across the reservoir or the main body of the dam. When the tailings have a slope of both length and width, the development of the shale hole is along the length of the tank, and there is no significant change in the volume of the external material due to the failure of the bed slope change.   

  The main factors in accidents include three factors: human, vehicle and road. In all accidents, there is error and disorder in one of the three mentioned factors. Human factors play a very important role in accidents and are the most important factors in accidents. Personality traits can affect risky driving behavior and people's perception of health and risk. The current research is correlational with regard to the purpose, application and method of execution, with the general goal of investigating and explaining the predictive role of neurotic personality traits. , excitement seeking and self-esteem were conducted with the mediation of emotion regulation in risky driving behavior in drivers of passenger vehicles in Kermanshah city. The statistical population of the present study included all the drivers of passenger vehicles in the city of Kermanshah, using Cochran's formula, 384 drivers were selected as the sample of the study using the available sampling method, and using Zuckerman's sensation seeking questionnaires (1978), Rosenberg's self-esteem scale (1965), Neo's 5 personality factor test, Manchester driving behavior questionnaire (1990) and Gross emotion regulation questionnaire were measured, and the relationships between research variables were also measured using the structural equation model test and    and amos software. was investigated and the following results were obtained: there is a positive and significant relationship between excitement seeking and risky driving behaviors, there is a positive and significant relationship between neuroticism and risky driving behaviors, there is a significant relationship between self-esteem and risky driving behaviors It doesn't exist, and the emotion regulation component had a significant mediating role between the variables. In general, people with higher neuroticism and excitement showed more risky driving behaviors, but the self-esteem component did not have much effect on risky driving behaviors in people.

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Due to their favorable biocompatible properties, titanium and its alloys are used as popular raw materials for making all kinds of implants. Therefore, the efficiency of the implant is always being developed in order to better adapt to the biological tissue and increase its retention time in the place of cultivation, in different ways that lead to the creation of an oxide layer on the surface. The aim of this research is to investigate the biocompatibility of titanium in different morphologies obtained from anodizing in alkaline and acidic electrolytes.  

   In the process of additive manufacturing of metals, the ability to predict and control the microstructure can reduce the need for subsequent heat treatment. In this research, the numerical simulation of the additive manufacturing process of 316L stainless steel was studied. The ability to predict and control the microstructure of materials in selective laser melting (SLM) requires understanding the thermal conditions during the solidification process. In this research, process parameters were selected with transient thermal characteristics, i.e. temperature and cooling rate. The relationship between the cooling rate and the temperature gradient during local freezing, and the control parameters of the laser selective melting process were investigated, which were the control parameters of the laser scanning speed and the thickness of the powder layer. Also, solidification parameters, namely thermal gradient (G) and solidification rate (R) were investigated to predict the microstructure. In this project, the cooling rate and thermal gradient during solidification were calculated numerically by solving the relevant heat transfer equation using the finite element method in Comsol software, and then the results included the solidification parameters mentioned on the solidification map of 316L stainless steel alloy to predict the solidification microstructure. was imaged The results of this research (obtained using simulation) showed that the microstructure of 316L stainless steel produced by the selective laser melting (SLM) process will be columnar or cellular dendrites. Also, it was found that high laser scanning speed (i.e. speed of 1000 mm/s) leads to finer microstructure. Furthermore, the values of G × R increase from the bottom to the top of the melt pool geometry, leading to a finer structure in the top region. But the values of G/R decrease from the bottom to the top of the molten pool geometry. Also, in this research, it was found that the greater the thickness of the powder in each layer, the lower scanning speed should be used so that the laser heat flux can melt the powder and the sub-layer completely. By increasing the laser scanning speed from 200 to 1000 mm/s, the width decreases from 85 microns to 58 microns and the depth of the molten pool decreases from 23 to 13 microns, but the length of the pool increases from 93 to 97 microns.

Tailings dams are structures builtto store waste from mining operations as well as mineral extraction operationsfrom ore. Tailings dams are completed over time and raised according to thevolume of tailings produced. The purpose of building these structures is tostore waste materials in order to prevent environmental pollution. In thisresearch, the amount of mineral tailings transferred due to a local gap farfrom the support in tailings dams with water in the reservoir is investigatedin a laboratory manner. It should be noted that three different water levelswere considered in this study. In order to validate the failure of the dam was repeatedthree times in each water level. According to the laboratory results, it wasobserved that three types of flow patterns can be seen in these failures. Thedimensions of the scour hole caused by the failure of the dam in the directionof the failure are 2 to 5 times that of the direction perpendicular to thefailure. It also found that with the increase of the water level, the volume ofthe discharging materials increases.

   امروزه، رشد سريع شهرها و توسعه كالبدي آن، بحران‌هاي مختلفي در زندگي شهري، از جمله كمبود مسكن را به وجود آورده است. در ايران نيز باتوجه‌به مشكلاتي كه در زمينه كمبود مسكن و به‌ويژه گراني آن وجود داشته، طرح مسكن مهر به‌عنوان محوري‌ترين سياست شناخته مي‌شود. پروژه مسكن مهر، بزرگ‌ترين طرح ملي مسكن در ايران است كه به علت گستردگي طرح، نياز به بررسي نتايج حاصل از اين تجربه و ميزان رضايتمندي ساكنان از آن، احساس مي‌شود. شناسايي عوامل مؤثر در ميزان رضايت و نارضايتي سكونتي ساكنان، مي‌تواند در جهت تحليل وضع موجود سكونتي و تصميمات آتي به‌منظور ارتقاي سطح كيفي محدوده‌هاي سكونتي افراد و جلوگيري از تكرار نواقص در ساير پروژه‌ها مؤثر واقع گردد. بنابراين، هدف اين پژوهش، ارتقاي كيفيت زندگي و ايجاد رضايتمندي در مجتمع‌هاي مسكن ملي از طريق شناخت آسيب‌ها و مشكلات موجود در مجتمع مسكن مهرهاي شهر كرمانشاه وهمچنين ارائة راهكارهايي جهت اصلاح آسيب‌ها و جلوگيري از تكرار نواقص مسكن مهر در طراحي پروژة جديد مسكن ملي است. اين پژوهش ازنظر هدف كاربردي، ازنظر روش تحقيق، نمونه موردي و ازنظر گردآوري داده‌ها، اسنادي و پيمايشي است. ابزار گردآوري داده‌ها اطلاعات كتابخانه‌اي و پرسش‌نامه است. جامعه آماري شامل ???? نفر ساكن مجتمع مسكن مهر دولت آباد كرمانشاه است كه با استفاده از فرمول كوكران ??? نفر به‌عنوان نمونه انتخاب گرديد. پرسش‌نامه تحقيق شامل ? متغير اصلي از شاخص‌هاي مؤثر بر رضايتمندي ساكنان با ?6 گويه است. اطلاعات جمع‌آوري‌شده از طريق نرم‌افزارهاي    و smart pls مورد تجزيه‌وتحليل قرار گرفتند. يافته‌هاي تحقيق نشان مي‌دهد كه ارتباط معناداري بين شاخص‌هاي استخراج شده و رضايتمندي سكونتي وجود دارد. اين پژوهش نشان داد كه ميزان رضايت ساكنان مسكن مهر دولت‌آباد از اين مجتمع به ميزان متوسط هست. سپس همة معيارهاي رضايتمندي سكونتي را در ? مجتمع مسكن مهر دولت‌آباد، رازي ? و ?، تلاش، رازي، زيتون، سجاديه، اميريه و چشمه سفيد كرمانشاه بررسي كرده و به آسيب‌شناسي اين مجتمع‌ها پرداخته شده است.

Review : There are various methods of surface coating to deal with corrosion and wear and other surface damage. One of the easiest and most economical coating methods is electroplating or electroplating. In the past, the best element for electroplating coating was chromium, but today, due to the toxicity of the ions obtained from the chrome plating bath, nickel is used instead of this element. Nickel coating is alloyed with elements such as tungsten, molybdenum, cobalt, etc. for better properties. One of the innovations that has led to the production of coatings with better properties and performance is composite coating through the deposition of base and reinforcing nanoparticles. TiO2 and SiC hard nanoparticles are among the most widely used nanoparticles for creating composite coatings. The simultaneous presence of these Nanoparticles in the coating, if they are properly dispersed, can give the coating good chemical and physical properties. In this research, nickel-tungsten coating along with TiO2 and SiC nanoparticles were applied with direct plating current on the substrate of low carbon steel and their wear and corrosion behavior was investigated. The effect of variable Ph parameters, plating time, plating current density, the amount of nanoparticles in the plating bath, and the presence of ultrasonic waves during plating were investigated. In order to check the wear resistance of the pin on the disk, the corrosion resistance of the polarization test was used to determine the existing phases as well as the grain size by X-ray diffraction patterns (XRD) and to check the microstructure of the coating by field emission scanning electron microscope (FESEM). The results showed that for nickel-tungsten coating, the optimal pH is 7.5 ± 0.5 and the optimal current is 200 mA/cm2. Adding TiO2 nanoparticles to the plating bath increased the wear and corrosion resistance as well as the hardness of the coating and reduced the size of the crystals. Adding SiC nanoparticles to the bath led to an increase in hardness and wear resistance, as well as a decrease in crystal size and corrosion resistance. Coating in the presence of ultrasonic waves with powers of 40 and 60 led to an increase in the abrasion properties and hardness of the coating, but the increase in the power of the ultrasonic waves led to a decrease in these properties, which is due to the distortion and removal of particles from the surface of the coating due to the high power of the ultrasonic waves. is. In all the powers of the ultrasonic waves, the corrosion resistance decreased due to the cracks in the microstructure.   

Forging is one of the bulk metalforming processes that has been used in the past centuries as an importantprocess in metal forming. An important point in forging processes is tocalculate the force and pressure required to form the piece.in this dissertation, the process ofopen die forging of a long billet with a circular cross section is analyzed andsimulated. The analysis has been done in two ways, the slab method and thebased on which the equations governing the slab method can be expressed andupper bound method. In the slab method, first a deformation model is presentedfinally the force required to perform the process is calculated.in order to analyze the process by theupper bound method, the deformed material is divided into three regions. Theseareas are separated by shear boundaries. The deformation model in this methodnot solvable, but in the analysis, this equation is solved by force optimization.is expressed by a two-unknown equation. In normal conditions, this equation isIn the first region, the Cartesian coordinate system is used, and in theof matter in this region. Then an allowable velocity field containinganalysis of the second region, the cylindrical coordinate system is used. Thethird region is modeled as the dead region, meaning that there is no movementmathematical relationships are obtained for the expressions of internal, shearhorizontal and normal components for the first region and an allowable velocityfield containing radial and peripheral components for the first and secondestimated.deformation zones are developed. Strain rate components are calculated andand frictional powers. By calculating the powers and optimizing the force, thegeometric shape as well as the force required to perform the process isThe results of the analysis arecompared with the data obtained from the finite element method (Deformsoftware). The results showed that there is an acceptable correlation betweenanalytical predictions and simulation results. Also, the constant effect ofsolution can be used in industrial applications to evaluate the load requiredfriction on small deformations on the amount of force is negligible. Thisissue to choose a deformation device with sufficient capacity.

   Skin cancer is one of the most common cancers in human societies and its prevalence is increasing dramatically. Melanoma is one of the most dangerous types of skin cancer, and the more the skin lesion grows, the lower the chance of cure. Early detection of cancer plays an important role in its treatment. Definitive treatment of melanoma cancer is possible with early detection. In this dissertation, a new method for diagnosing skin cancer was presented. In this method, two types of discrete and stationary wavelet transform were first applied to the images. A number of statistical features were then extracted from these converted images. Also, various global, local, etc. features were applied to the gray and color surface images. In the next step, to improve the results, the extraction features were combined to obtain the best combination of features that >Keywords: Melanoma Cancer, Discrete Wavelet Transform, Stationary Wavelet Transform, Least Squares Support Vector

Sustainability - Sustainable architecture - Sustainable development - Climate - Climate empowerment   

AbstractToday, the issue of pollutants in water resources such as organic matter and minerals is of great importance. Among the available water pollutants, paints, which are a group of organics with a complex structure and enter the environment through various processes such as dyeing, can be considered as the main sources of water pollution.According to research on the removal of dyes from water sources, photocatalytic degradation (a branch of the advanced oxidation process) is an efficient and low-risk method or the so-called green. Among the photocatalytic compounds developed, the two compounds zinc oxide and titanium dioxide are known to be more widely used, so-called more industrial, because of their cost-effectiveness, high jump, no pollution, and low energy requirements. Zinc oxide compound, which is white and environmentally friendly, is a non-toxic compound with high stability, high light sensitivity, wide energy gap and photocatalytic properties and high efficiency, which has attracted much attention in electron production.Pure photocatalysts such as ZnO have disadvantages such as rapid electron-hole recombination rates and low photocatalytic efficiencies in aqueous media, which can be improved by a variety of methods. Is another photocatalyst. In this way, the photocatalytic property of the host semiconductor is significantly increased. In recent years, studies have been conducted on the positive effect of ZnO on the photocatalytic process, which include increasing the specific surface area, coupling ZnO with other semiconductors, correcting ZnO with metals and non-metals, reducing particle size, and sensitizing zinc oxide. Due to the importance of dye removal from wastewater of various industries such as textiles, in this study, the efficiency of the photocatalytic process of perovskites with ABO3 structure such as LaNiO3 has been investigated. LaNiO3 perovskite has good photocatalytic properties and is one of the semiconductors with limited band gap that is activated when exposed to visible light, the synthesis of which is also investigated in this study.  

  First, by reviewing the scientific literature, suitable conditions for the electrodeposition of nickel-tungsten nano-coatings are determined, and after preparing a suitable coating, nitriding operations are performed on the samples. Further erosive corrosion of pure steel, nickel and tungsten nickel coating were investigated .The electron microscope and X-ray diffraction studies are performed at each step.   

    Erosion-corrosion is a main type of damage mechanisms taking place in equipment and hydraulic components exposed to corrosive flowing fluid. Hence, in order to applications of dual phase steels for such engineering components, it is essential to have a comprehensive understanding of their erosion-corrosion behavior and involved affecting variables. The microstructure of dual phase steels is governed by the heat treatment variables like temperature of medium in which the samples are rapidly quenched from intercritical austenitizing temperature. As a results, the change in quenching medium temperature is expected to have a significant impacts on the erosion-corrosion resistance of dual phase steels. The purpose of this work was to provide comprehensive information on this issue and to evaluate erosion-corrosion correlation with the hardness and erosion resistance of dual phase steels. In this regard, several sets of samples of Ck45 steel were austenitized at 730 oC for 60 min, then quenched and held 120 min in water and/or salt bath with different temperatures ranging of 25 to 400 oC to obtain dual structures with ~40 vol. % fraction ferrite. Optical microscopy and scanning electron microscopy utilized to characterize the samples microstructures. The hardness of specimens were evaluated using Brinell hardness test method. Erosion and erosion-corrosion tests were carried out by immersion of samples in a solution of distilled water, 3.5 wt% NaCl and 1 wt% Al2O3 and rotating them with 715 rpm (9 m/s) for durations of 24-120 h. The slope of variation of mass loss various duration test was determined as erosion or erosion-corrosion rate. The obtained results revealed that increasing the quenching medium temperature from 25 to 400 ?C leads to a reduction in hardness and erosion resistance. The erosion rate was correlated with quenching medium temperature as a power model with exponents of 5.7. The rate of erosion-corrosion was raised with increasing quenching medium temperature from 25 to 325?C, while austempering at higher temperature resulted to improvement of erosion-corrosion resistance when compared to specimen austempered at 325 oC.   The power model was valid for correlation between the erosion rate and Brinell hardness, while there was no significant correlation between erosion-corrosion rate with hardness and rate of pure mechanical erosion. Compared with pure mechanical erosion in non-corrosive fluid, the degradation rates were higher than 193% to 305% and 21% to 132% for samples austempered at temperatures below and above 325 oC, respectively, when the erosion tests were performed in the aggressive condition. The erosion-corrosion resistance of ferrite-bainite samples prepared by austempering at temperature of 400 oC was similar to ferrite-martensite sample provided by quenching into water at temperature of 90 oC and had the best results compared to the rest of the specimens, except for quenched samples in water at 25 ° C.   While the pure mechanical erosion resistance of later was approximately  three time  greater  tha  that of former. These results indicate that the type of hard phase in the dual phase steel does not have much effect on its efficiency in the corrosive flowing fluid, if the appropriate temperature was selected for the quenching medium. But, ferritic-martensitic dual-phase steel is preferred for use in the non-corrosive environment and/or when the samples are subjected to cathode protection.

  In this research, the AISI304 steel was bonded successfully with MBF-15 and MBF-80 interlayers by Transient Liquid Phase [1]method. Then friction stir process[2] was performed on the bond region and the effect of the process on microstructure and mechanical properties was investigated. The base metal and each of interlayers separately was assembled and the bonding operation was done in 11350c temperature for 20 min in a semi-vacuum environment furnace. Afterward Friction Stir process applied with using a designed tool made from tungsten carbide material. The process was accomplished with a milling machine. Rotating speed of tool was 600 Rpm/min and traverse speed was 10 mm/s. the process was applied at two side of the bond line. Processed and not processed samples were prepared and investigate with optical and scanning electron microscope. The microstructure of samples compared with each other. To analyze the composition and phase recognition energy dispersive spectrometry[3] and XRD was used. To evaluate the mechanical properties and the effect of FSP on it shear strength test and micro hardness performed. The microstructure evaluation showed that before FSP for each of interlayers, there were some eutectic phase in center of bond and residual phase in the diffusion zone of TLP. Before FSP, for MBF-15 interlayer, the central phase is Ni-Si, Fe-B, Ni-B and CrB4 in DAZ of TLP. The eutectic phases in the central zone of bond by MBF-80 interlayer are Fe-B-Ni-B and brittle Cr5B3 in DAZ. These eutectic and residual phases reduce the mechanical strength of the joint.FSP was applied as a technique to modify the distribution of alloying elements and intermetallic phases. Underneath of FSP route, 3 zones were formed: 1. Nugget zone that distribution of intermetallic is perfect. 2.Thermo Mechanically Affected Zone[4]. and. 3. Heat Affected Zone [5]that the quantity of intermetallic phases is reduced because of dissolution of eutectic and residual phase. The shear strength and hardness of the nugget zone after FSP will be better than before FSP for both interlayers. This improvement for joint with MBF-15 interlayer is better than MBF-80.   And shear strength of joint with MBF-15 interlayer is close to base metal shear strength after the process.1-TLP2-FSP3-EDS