One of the fundamental challenges in photovoltaic (PV) systems is the rise in panel temperature under intense solar radiation, which leads to reduced efficiency and service life. The use of phase change materials (PCM) as thermal energy storage can help reduce the surface temperature of panels. In this study, the combination of PCM with metal foams (MF) is investigated; metal foams, due to their high porosity and suitable thermal conductivity, can accelerate heat transfer and reduce PCM melting time. This research employs a computational fluid dynamics (CFD) approach to numerically simulate a PV-PCM-MF system and analyzes the effect of parameters such as metal foam porosity and geometric dimensions of the heat sink on the thermal and electrical performance of the solar panel. The main objective is to present a novel method for optimizing heat transfer and enhancing the electrical efficiency of photovoltaic systems. The results of this study are expected to demonstrate that appropriate selection of cavity geometry and optimal combination of PCM and metal foam can lead to reduced panel operating temperature, increased thermal storage capacity, and significant improvement in electrical efficiency. This research provides practical guidance for the optimal design of hybrid PV-PCM-MF systems in the field of renewable energy.

   Slope stabilization is one of the important challenges of geotechnical engineering, and failure to pay attention to it can lead to dangerous subsidence and collapse of soil. In the Shahu region, frequent landslides and increased slope displacement have made it more evident than ever before the necessity of investigating and selecting appropriate stabilization methods. The present study investigated and compared three slope stabilization methods, including anchorage, anti-slip piles, and retaining walls, using finite element numerical analysis and PLAXIS 2D software. The main objective of the study was to determine the effectiveness of each method in reducing total slope displacement, increasing the safety factor, and controlling failure lines. In the analyses, geometric and mechanical parameters such as anchor angle and length, pile center distance, and the distance of the retaining wall from the slope toe were examined as key variables. The results showed that the anti-slip pile had the greatest effect in reducing total displacement and increasing the safety factor; the maximum safety factor of 1.405 was recorded at a distance of 0.5 m from the highest point of the slope, which is beyond the design criterion limit (1.25). The anchoring method has a good performance in stabilizing the surface layers of the slope, but excessive increase in the anchoring length causes stress concentration and increased local settlement. While the retaining wall has limited control over the total displacement and is more suitable for surface stabilization and local control of displacements. The analysis of the failure lines also showed that the combination of the load transfer mechanism, system stiffness and failure depth plays a decisive role in the stabilization performance. The findings are consistent with previous studies and emphasize that the selection of the optimal method should be based on the geotechnical properties of the soil, failure depth and implementation constraints. This research also suggests that the combination of methods, 3D modeling and intelligent monitoring can increase the prediction accuracy and efficiency of slope engineering designs. Keywords: Slope stabilization, anti-slip pile, anchorage, retaining wall   

The main goal of e-government is to create an electronic city that uses digital services based on need. Governments play an important role in protecting property rights, providing infrastructure, functioning of monetary, financial and human resources markets, monitoring economic activities and controlling corruption. This research is an applied research based on the purpose, a descriptive research based on data collection and a quantitative and qualitative research based on the approach or methodology. In this research, content analysis and Delphi methods are used to collect data.  

      Due to the significant share of the building sector in total energy consumption, investigating innovative methods to reduce energy use and enhance energy efficiency in this sector is of particular importance. One of the effective approaches in this regard is the use of phase change materials (PCMs) to improve the thermal performance of the building envelope. In this study, the performance of six types of phase change materials with five different thicknesses (ranging from 0.01 m to 0.05 m) was simulated using EnergyPlus software for a 48 m² residential building located in Kermanshah, during the period from November to March. The results showed that the building’s heating load, which was 3914.38 kWh in the reference case, decreased to 3601.94 kWh after incorporating PCM. The highest reduction in heating load, equal to 312.43 kWh, was achieved with paraffin RT21, which has a melting temperature of 21 °C, corresponding to 7.98% energy savings. Furthermore, it was found that increasing the PCM layer thickness beyond 4 cm had no significant effect on improving thermal performance, and the greatest impact of PCM occurred when it was applied to the inner layer of the building envelope.

   Abstract Two-phase matrix carbide ductile irons are a new idea i  ired by the processes of producing two-phase matrix ductile irons and producing austempered carbide ductile irons containing free carbide. As an emerging align="left" dir="LTR" >Keywords: Intercritical austenite, carbide ductile iron, austemper temperature, corrosion behavior, two-phase contex.

  Abstract Multiple sclerosis (MS), as a chronic and disabling disease of the central nervous system, has created many challenges in the field of diagnosis and treatment for doctors and health systems. Rapid and accurate identification of lesions caused by this disease in MRI images due to structural similarities with other brain tissues requires the use of accurate and advanced image processing and machine learning methods. In this study, an optimized model called DE-CNN-Gray is presented for automatic diagnosis of MS from gray-scale MRI images. In this model, a convolutional neural network is first designed and then the network structure including the number of layers and effective parameters is optimized using the Differential Evolution algorithm. The main goal of this optimization was to increase the classification accuracy and reduce the computational complexity of the model. Model evaluation using 5-Fold validation showed that the proposed method performed very well in identifying MS patients with an accuracy of 99.40%, sensitivity of 98.89%, positive accuracy of 99.90%, and F1 score of 99.33%. The results show that the DE-CNN-Gray method, using gray images and meta-heuristic algorithms, can be used as an accurate, fast, and low-cost tool for developing MS diagnosis systems and play an effective role in improving the treatment process and reducing treatment costs . Keywords: MS, Deep Learning, Convolutional Neural Network, Differential Evolution Algorithm, MRI, DE-CNN-Gray,Medical Diagnosis, Image Processing.

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در بسياري از صنايع مهندسي ذرات جامدي كه همراه سيالات حمل مي¬شوند، توانايي آسيب سايش به خطوط لوله و خصوصاً اتصالات را دارند و آن¬ها را در معرض نشت و شكست قرار مي¬دهند. در واقع سايش يك مكانيسم مكانيكي است كه سبب جداشدن مواد از سطح به دليل برخورد مكرر ذرات جامد است و خسارت¬هاي مالي و جاني در پي دارد. به همين سبب باعث شده است كه اين موضوع اهميت پيدا كند و روش¬هايي در جهت كنترل سايش پيشنهاد شود. يك روش مناسب براي پيش¬بيني نرخ سايش حل ديناميك سيالات محاسباتي است كه در سال 1990 امكان استفاده از اين روش فراهم شد. پژوهش حاضر سعي در استفاده از رويكرد اويلر - لاگرانژ با نرم‌افزار انسيس فلوئنت دارد بدين منظور كه شبيه‌سازي جريان سيال (فاز پيوسته) در ديدگاه اويلري و شبيه‌سازي رديابي ذرات جامد (فاز گسسته) در ديدگاه لاگرانژي صورت مي¬گيرند. در ادامه فرايند استقلال از شبكه و ذرات براي جريان دوفازي گاز - جامد در هندسه زانويي 90 درجه استاندارد انجام مي¬شود. همچنين اعتبارسنجي داده¬هاي عددي حاضر مساله با داده¬هاي تجربي ديگر مقالات تحت شرايط يكسان، براي جريان تك¬فاز و دوفاز مقايسه مي¬گردند تا نتايج قابل‌قبولي لحاظ گردد. در همين راستا سبب شد مدل آشفتگي از نوع تنش رينولدز، كوپل يك¬طرفه، مدل سايش اوكا، مدل ضريب بازگشت ذرات گرانت و تاباكف و نيروهاي وارده بر ذرات شامل پسا، جرم مجازي، شناوري و گرانش در حل عددي اين پايان‌نامه انتخاب شوند. پارامترهاي زيادي در ميزان سايش دخيل هستند كه در اين پژوهش برخي پارامترها شامل سرعت جريان، اندازه قطر ذرات، نرخ ورودي ذرات و تأثير زبري سطح ديواره مورد بررسي عددي قرار داده شدند. در بين اتصالات، زانويي¬ها در معرض خطر جدي¬تري هستند. با پيشنهاد جايگزيني اتصالات ديگر كه هدف و ماهيتي شبيه به كارايي زانويي دارند، انتخاب مي¬شوند و سايش را نسبت به زانويي 90 درجه استاندارد كاهش مي¬دهند. اتصالات شامل دو نوع خم مايتر، سه نوع اتصال كور، زانويي كاهنده و دو نوع زانويي كروي شكل هستند. شرايط حل عددي براي تمام اتصالات جهت مقايسه نتايج با يكديگر به¬صورت مشابه تنظيم مي¬گردند. سپس نتايج عددي نهايي پايان‌نامه بيان مي¬كند كه در سرعت جريان و قطر ذرات يكسان براي بحراني‌ترين حالت، اتصالات ذكر شده مقاومت سايشي را 22/5% تا 39/6% نسبت به زانويي 90 درجه استاندارد افزايش مي¬دهند.

Cooling of electronic equipment is a fundamental challenge in the electronics industry, so the development of new electronic systems depends on solving this challenge. In a Core I7 processor, more than 731 million transistors are accumulated in an area of 270 square millimeters, and their design thermal power reaches 140 watts. Removing this thermal load requires new methods. In recent years, the use of phase change materials in these systems has shown that these materials are effective in improving the thermal performance of heat sinks. Due to the increasing use of these materials, it is necessary to examine their thermal behavior in different conditions and to study the conditions where the presence of these materials leads to the improvement of the performance of heat sinks. These conditions depend on the geometry and materials of the heat sink components as well as its functional conditions. In this thesis, the thermal efficiency of a thermal heat sink equipped with a phase change material is investigated. The type of phase change material and its mass fraction in the presence of vanes and the arrangement of vanes are among the parameters that are studied. In addition, the efficiency of the heat sink may change over time depending on the amount and type of PCM, and therefore it is necessary to study this parameter over time. The results of this study can determine the conditions in which the presence of PCM leads to the improvement of the efficiency of the heat sink and introduce the appropriate limit for the use of PCMs. Also, in this study, it has been investigated that the presence of the valley in which wall of the heat sink has improved the performance of the heat sink in terms of cooling.  

     Medical imaging plays an important role in clinical diagnosis and treatment. Medical imaging is a way to show the anatomical structures of the body with the help of X-rays, which is obtained from computed tomography and magnetic resonance imaging. But often this type of photography is more suitable for physiological function than anatomy. With the development of computer and imaging technology, medical imaging has greatly affected the medical field. Since the quality of medical imaging has had a great impact on disease diagnosis, medical image processing has become one of the most important clinical applications that store and retrieve images for the future, which are prerequisites for accurate storage of these images. Bones are solid organs in the human body that protect many important organs such as the brain, heart, lungs and other internal organs. The human body has 206 bones of different shapes, sizes and sizes. The largest bone is the femur, and the smallest is the ossicle. A common problem in humans is "bone fracture". A bone fracture can be caused by an accident or any other case where a lot of pressure is applied to the bone. There are different types of bone fractures: oblique, compound, comminuted, spiral, girrin's stick1 and transverse. Compared to other methods, X-ray imaging provides precise details of bones and less details of tissue and muscle, which makes it easier to detect fractures

  ased on the studies and investigations carried out and with the aim of designing and producing an effective and practical structural damper in the consumption of earthquake energy and high ability to protect the structure against damage caused by earthquakes with the ability to install and replace easily and also cost-effectively. From an economic point of view, after examining many mechanisms and presenting various initial ideas, a damper with an energy consuming mechanism based on cyclic bending of cheap steel rods was designed and built. In such a way that these inexpensive rods, after bearing the cyclic load and deformation of the plastic, and after losing their ability to absorb energy due to the deformation of the plastic, can be easily replaced with a new rod. So, our damper will be serviceable again.

   ABSTRACT    Since the nailed walls of the excavation are considered as permanent structures, its necessary to study and describe the creep behavior of the nailed wall. For this reason, it is necessary to investigate more the soils that have creep potential. Generally, soft clay soil or clay with a high plastic index show a greater tendency to creep than other soils, which has a negative effect on the stability of the excavated wall in the long term. For this reason, the use of nailing method in soft clay soils has certain sensitivities and the parameters of soft clay, the effect of various behavioral models and the effect of choosing the type of analysis (plastic or consolidation) should be investigated in order to have a correct understanding of the development of soil creep and long-term deformations.It should be mentioned that excavation stabilization by nailing method is one of the suitable and practical methods in most urban excavation , which can be effective as a scientific and practical method due to the lack of interference with the work environment (excavation area). It should be checked whether this method is effective in soft clay soils or not

Abstract Research Aim: Floods cause extreme and irretrievable human and economic loss. Estimating flow of floods leads to designing hydraulic structures in order to prevent flooding. The aim of this thesis is to find a formula to predict the flow of floods using physiological parameters in ungagged stations. Research method: In this research at first the most important and effective factors to estimate peak flow would be investigated. Then the parameters would be probed through Exploratory factor analysis technique and the most sufficient ones would be chosen. In order to increase the accuracy of this investment, dimensionless parameters were used. Afterwards regression analysis relates a dependent variable, which is discharge, to explanatory variables and generates equations for estimating the peak flow. To achieve more complicated and more accurate formula and also increase coefficient of determination utilizing genetic programming algorithm is helpful. Findings: The most important factors to affect floods through some recurrence intervals included 2, 5, 10, 25, 50 and 100 years were examined and some formulas were presented as a way to predict peak flow. Conclusion: Efficacious factors in estimating peak flow are drainage area, storage, lake area, annual runoff and slope of watershed. Implementing dimensional analysis and genetic algorithm gives some equations to predict peak flow which the coefficient of determination is more than using regression. Keywords: Peak flow, Regression, Non-dimensional parameters, Factor analysis, Genetic Programming هدف از اين پژوهش پيش بيني دبي پيك در مناطق فاقد داده‌هاي آماري با استفاده از پارامترهاي بدون بعد مي¬باشد.

  

   Water is a vital resource for humans, both for consumption and the production of goods. Today, with the rapid development of industries, water pollution caused by heavy metals has become one of the most significant environmental problems and a key goal of wastewater treatment. Among the methods for water purification, membrane filtration has garnered considerable attention. In this study, we conducted the fabrication and investigation of polyethersulfone-based nanocomposite membranes using the phase inversion process, incorporating graphite carbon nitride nanoparticles and nanoparticles functionalized with salicyl aldehyde, indigo, and indigo carmine. This study aims to examine the impact of adding nanoparticles on heavy metal removal and anti-fouling properties. We performed Fourier transform infrared spectroscopic analysis, X-ray diffraction, and scanning electron microscopy to study the structure of nanoparticles and verify the functionalization of nanoparticles. Additionally, scanning electron microscope analysis, contact angle measurements, and porosity assessment were conducted to investigate the structure of nanocomposite membranes. The fabricated membranes were evaluated for pure water flux, the ability to remove Cu+2 heavy metal ions, antifouling properties, and flux recovery ratio against a milk powder solution. The results demonstrate an increase in the hydrophilicity and pure water flux of nanocomposite membranes when nanoparticles are added, primarily due to the presence of hydrophilic functional groups on their surface. Surface scanning electron microscope images and cross-sections of the nanocomposite membranes show that all the produced membranes possess an asymmetric structure, characterized by a compact, thin, and dense upper layer and a porous bottom layer with finger-like structures. Regarding the filtration of copper nitrate solution, nanocomposite membranes containing 0.5%wt of g-C3N4/Indigo and g-C3N4/IndigoCarmin displayed removal efficiencies of 97.43% and 98.35%, respectively. The membrane containing 1.5%wt of g-C3N4/Salicylaldehyde exhibited a 98.05% removal of copper ions, significantly outperforming the pure polyethersulfone membrane and nanocomposite membrane containing unmodified nanoparticles, which achieved removal efficiencies of 37.23% and 70.65%, respectively. This makes the modified nanofiltration membranes highly suitable for practical applications. The flux recovery ratio for nanocomposite membranes containing 1.5%wt of g-C3N4/Salicylaldehyde, 0.5%wt of g-C3N4/IndigoCarmin, and 0.5%wt of g-C3N4/Indigo was found to be 86.58%, 90.16%, and 79.93%, respectively. These values indicate superior antifouling properties compared to the pure polyethersulfone membrane, which achieved a 61.44% flux recovery ratio. Keywords: Membrane filtration, Graphite carbon nitride, Wastewater treatment, Surface properties, Antifouling

  Global awareness of climate change and global warming, which with the rapid growth of the economy and population, has significantly increased the energy and resources needed by humans in the past few years, and the negative consequences of the emission of greenhouse gases and the subsequent greenhouse effect. It is widely accepted. The building sector is one of the largest producers of carbon dioxide pollutants in the world, so it can play an important role in achieving the goals of reducing pollutants. Therefore, the necessity of research on the climate empowerment category seeks to design an ideal residential complex that, in addition to To reduce the consumption of fossil energy and the production of carbon dioxide, to provide a favorable environment for the life of the people of that complex. This thesis aims to identify policies and strategies of sustainable development in order to improve building energy efficiency and reduce carbon emissions. Based on such a goal, the research method of this dissertation is quantitative and a combined strategy that includes descriptive-analytical and simulation is used. In line with the final goal, in the theoretical part, firstly, to review, analyze, recognize and collect information related to sustainable development, sustainable architecture. Static and dynamic solutions have been discussed and after evaluating the examples of the world based on the criteria extracted from the theoretical part of the research as well as knowing the design platform, finally presenting and applying the proposed solutions including insulation (thermal insulation and double-glazed windows), Trombe wall design, canopy And the use of solar cells to design a low-carbon residential complex has been discussed. In short, the results of this research can be expressed as follows: the implementation of the aforementioned solutions, which are all based on sustainable development policies, has been able to reduce energy consumption in the heating sector by 50% and in the cooling sector by 86%. Also, the use of cell Photovoltaic systems have been able to provide approximately 63% of the building's energy needs. The use of these solutions in the designed building will reduce the production of carbon dioxide consumed. So that this amount of production has been negative for 9 months, the total amount of carbon dioxide production during the year is -16,160.13 kg. That is, throughout the year, the building will reduce carbon dioxide.

  atural disasters kill an average of 60,000 people annually and account for 0.1% of global deaths. Events such as earthquakes and tsunamis cannot be prevented and have high losses in human life. Historical data shows that the world has seen significant reductions in accident deaths through early warning, more resilient infrastructure and emergency preparedness. Housing reconstruction programs play a decisive role in disaster recovery, and providing temporary housing is an important step in these programs. Temporary housing allows victims to have a private and safe place to return to their normal lives while permanent homes are being rebuilt. However, the long-term effects of temporary housing projects are often destructive, and it is important to assign a sustainable function to temporary homes and plan for their future. The aim of this thesis is to improve the conditions of temporary settlements and increase the level of satisfaction of the homeless population caused by the earthquake and reduce the vulnerability of the earthquake victims who are forced to accept these settlements. Considering the main features of temporary settlements, this thesis tries to propose a new solution using mobile architecture that is easily portable and flexible, and at the same time tries to provide the goals of sustainable living. This thesis uses a combined analytical-modeling and simulation research method. The community under study is the areas affected by accidents and disasters, and the sample under study is the village of Ramki Ramadan, one of the earthquake-affected villages of Sar Pol Zahab, Kermanshah.

   The prevalence of frequent earthquakes throughout the world and the extensive human and financial damage caused by this phenomenon have prompted many researchers to explore ways to reduce this damage. Numerous systems have been employed to mitigate the aforementioned damage, among which seismic isolators can be considered one of the most important. Fiber-reinforced circular isolators represent a novel type of seismic isolator composed of alternating layers of elastomers and fiber fabrics. Utilized in an unbonded (non-connected) application, these isolators were placed above the foundation and below the superstructure, successfully isolating the superstructure from ground motions during an earthquake event. In an unbonded application, shear forces are transferred to the isolator through friction between the isolator’s contact surfaces and its contact supports. When the isolator is subjected to a lateral force, it undergoes a pseudo-rolling deformation, resulting in a nonlinear force-displacement curve. Consequently, the existing analytical relationships for traditional elastomeric isolators cannot be generalized to this type of isolator. In the isolator design process, determining the lateral stiffness under the influence of lateral forces is of particular importance. In the literature, only one analytical relationship has been proposed for this type of isolator, which, according to the investigations conducted in this thesis, does not provide a suitable approximation of the lateral stiffness in many cases. In this dissertation, not only has the existing relationship been modified, but also novel analytical correlations, which have been calibrated utilizing the outcomes of finite element simulations of fiber-reinforced circular isolators for the purpose of generating their lateral force-displacement diagrams. To verify the accuracy of the suggested associations, the force-displacement curves were assessed by comparing them with the hysteresis loops obtained from four experimental laboratory specimens. The equations introduced in this study can effectively approximate the lateral stiffness derived from laboratory experiments on isolators, exhibiting an average accuracy of 20% for shear strains of up to 0.5, and improving to an average accuracy of less than 10% for greater strains. Consequently, these correlations have sufficient precision for utilization in the initial design stages of unconnected fiber-reinforced circular isolators.

  Due to events such as the advancement of technology, consumerism of goods, attention to fleeting needs and such things, in the present era, the quality-oriented world has given way to an advanced and quantitative-oriented world. In such a way that the meaning of many issues has been forgotten and consigned to history. In fact, the house is not an exception to this rule; So that it has lost its meaning and nature to a large extent. The lack of a suitable home makes a person feel lost and homeless in this busy world. As a result, the concept of living in a beloved shelter has gradually become dim and meaningless. There are various factors that improve the quality of the house, one of which is the correct and rational use of materials in the architecture of the house. In this regard, the current thesis, assuming the center of human and his need to understand the meaning of his house, seeks to revive a part of the forgotten quality of the house by means of brick materials. In general, in order to achieve this important in the research process of this thesis, first, relying on the correlational research method, it was determined that there is a relationship between bricks and the meaning of the house, so that these two variables affect each other. . In the next stage, an open interview was conducted with those respondents who believed that there is a connection between bricks and the meaning of the house, and with the help of qualitative research method, primary codes were extracted from the interviews and then From the centralization of the codes, concepts such as: sensory perception, Iranian identity, revitalization of the sense of place, stability, personalization and atmosphere were created. The information obtained improves the quality of the house, and in general, these information are the characteristics attributed by the respondents to the brick materials used in the houses. Finally, the results obtained from the research part of this thesis show that a significant number of people in Kermanshah consider brick as one of the appropriate materials to create meaning and improve quality in the exterior and interior of the house.

بيماري‌هاي ريه داراي آمار بالاي مرگ و مير در جهان هستند. دراين‌ميان آسم به عنوان شايع‌ترين بيماري شناخته‌مي‌شود و طبق گزارشات در سال ???? بيش از ?? ميليون نفر در آمريكا مبتلا به آسم بوده‌اند. بسياري از روش‌هاي درماني بيماري‌هاي ريوي و همچنين برخي بيماري‌ها، استنشاقي مي‌باشند، بنابراين شناخت رفتار ذرات استنشاقي (آلودگي‌ها و ذرات دارويي) همراه هوا درون مجاري تنفسي امري ضروري است. در مطالعه حاضر چهار نسل از ريه يك خانم ?? ساله سالم و غير سيگاري از تصاوير پزشكي سي تي اسكن استخراج شد. هندسه به 7 ناحيه تقسيم شد، سپس توسط شبكه بي‌سازمان با روش هموارسازي و با سلول‌هاي چندوجهي جهت حل عددي شبكه‌بندي گرديد. جهت شبكه‌بندي، ابتدا هندسه وارد محيط نرم‌افزار اسپيس‌كليم شده و در آن‌جا يكپارچه‌سازي هندسه انجام شد. سپس با استفاده از قابليت توپولوژي مجازي محيط انسيس مشينگ ، صفحات انتخاب شده و با گزينه تركيب سلول، تلفيق صفحات جهت ورود به محيط فلوئنت مشينگ انجام‌شد. سپس به وسيله استقلال حل از شبكه، شبكه مناسب انتخاب شد. از مدل آشفتگي k-?   براي شبيه‌سازي جريان آرام تا آشفته استفاده‌گرديد. ذرات با ديدگاه لاگرانژي و با استفاده از مدل فاز گسسته به ناحيه محاسباتي تزريق شد و مسيريابي و مدل‌سازي الگوي نشست در نواحي مختلف انجام شد. بر روي ساختار جريان در مجاري تنفسي براي نرخ‌هاي جريان مختلف و اثرات پديده‌هاي مختلف به‌وجودآمده در اين مجاري بر روي نشست ذرات بحث گرديد. الگوي نشست ذرات براي نرخ‌هاي مختلف جريان، به صورت منطقه‌اي و كلي به‌دست‌آمد و اثر نرخ جريان، اندازه و شكل ذرات بر ميزان نشست بررسي شد و در نهايت با استفاده از بهينه‌سازي و بهره‌گيري از روش پاسخ سطح و الگوريتم ژنتيك، حالت بهينه براي كمينه و بيشينه نشست ذرات در ناحيه درخت برونش به‌دست‌آمد. راندمان نشست بر حسب پارامتر برخورد نشان داد كه در تمامي نواحي مدل از جمله دهان- گلو، ناي و درخت برونشي، برخورد اينرسي نقش مهمي در نشست ذرات دارد. تحليل ساختار جريان سيال در مدل هندسه نشان داد كه جريان برگشتي، تشكيل گردابه و جت حنجره همگي بر ساختار جريان هوا و الگوي نشست ذرات اثرگذار هستند. ناحيه دهان-گلو داراي بيشترين كسر نشست به ازاي نرخ‌هاي جريان مختلف است. نتايج نشان داد كه تزريق به دو صورت تك ذره و استفاده از تابع توزيع بر ميزان نشست ذرات اثرگذار است. همچنين افزايش قطر ذرات باعث تغيير الگوي نشست ذرات شده و كسر نشست در ناحيه دهان-گلو افزايش يافت و شكل ذرات با اثرگذاري بر روي ضريب پسا، موجب تغيير الگوي نشست ذرات گرديد. از جمله نتايج ديگر اين بود كه بيشترين كسر نشست مربوط به ذرات كروي است. بررسي همزمان اثر قطر، شكل ذرات و سرعت ذرات و آناليز حساسيت نشان داد كه قطر با تاثير 60%، موثرترين پارامتر بر ميزان نشست ذرات است و پس از آن، ضريب شكل و سرعت قرار مي‌گيرند. در نهايت پيش‌بيني الگوريتم ژنتيك، بيشينه نشست ذرات در ناحيه درخت برونش را، 17% گزارش‌كرد، درحالي‌كه براساس نتايج عددي بيشينه نشست ذرات در ناحيه درخت برونش 20% گزارش شد. همچنين كمينه نشست ذرات توسط الگوريتم ژنتيك در ناحيه درخت برونش، 2/0 % گزارش گرديد، درحالي‌كه براساس نتايج عددي كمينه نشست ذرات در اين ناحيه، 24/0 % گزارش‌شد.   

Aluminum 3819 due to its good corrosion resistance and high strength-to-weight ratio in marine, military, pipe- It is widely used in pressure vessels, shipbuilding, refrigeration industries, oil rigs and gas transmission lines. among All aluminum alloys, alloy 3819 for all welded assemblies, tanks with the highest welding efficiency and maximum strength, connection of marine equipment, bridges, cargo ships, heavy ships and marine organizations, TV masts, grinding equipment, recycling machine body transfer equipment and wherever needed Corrosion resistance equipment is widely used. A Ag/Sn/Ag system to Shar et al connected with ultrasonic assistance and concluded that the acceleration of Ag atomic penetration with ultrasonic assistance is 6 3 times faster - - than the traditional TLP connection. Gio et al. fine-grained 4897 aluminum alloys with zinc interlayer TLP method with the help of ultrasonic bonding and reported that long ultrasonic time increases Zinc penetrates into aluminum. Li et al. for bonding Ag/Mg using ultrasonic assisted TLP method used and obtained the optimum shear strength of 68 MPa in a short period of 7 seconds. At This research has examined the TLP connection with the help of ultrasonics. This type of connection can not only connect with It provides high mechanical properties but also acts as a low temperature joining method. TLP with help Ultrasonic does not need shielding gas and can accommodate complex structures. Until today TLP It is used to connect different materials with the help of ultrasonic.  

The rapid economic growth in the world has led to anincrease in energy consumption during the last decades. According to recentstudies, the energy consumption of cooling and heating systems in buildings isabout 60%. As a result, any development in thermal system technology to lessenenergy consumption, especially in buildings, is welcomed. Phase changematerials (PCM) with high density for energy storage are one of the mosteffective ways to reduce energy consumption in buildings. In this thesis, usingDesign Builder version 7 software, heat transfer of a 4x4x3 electrical facilityroom located in Tehran city is simulated. Throughout these simulations, thethermal behavior of wall equipped with PCM layers has been examined. The various parametersof wall and PCM considered in the simulations include the thickness,conductivity coefficient, melting temperature of PCM material, and also heatgeneration within the room. The results showed that by increasing the thicknessof PCM, the amount of daily thermal load of the building decreases and as aresult, the thermal performance of the room is improved. By changing thethickness of PCM from 5 to 10 cm, the thermal performance coefficient of PCMincreases by 20-25% depending on the melting temperature of PCM. It is foundthat there is an effective thickness for PCM, after which increasing thethickness has a negligible effect on reducing the thermal load. As anotherresult, it was found that the conductivity coefficient has a small effect on thethermal performance coefficient so that for all the studied cases, the effectof conductivity changes in the range of 0.2 to 2 W/m2 °C on the thermalperformance coefficient is less than 13%. Also, the results showed that anincrease in the internal production of heat, leads to a decrease in the valueof the thermal performance coefficient, and in this case, the phase changematerial has a poor performance.  

  In this research, the effect ofroughness on thermal creep flow in microchannels has been investigated. Forthis purpose, a planar microchannel is considered in which a linear temperaturegradient is applied on the walls. In order for the wall temperature gradient tobe the only factor for creating the flow, the pressure at the inlet and outletof the microchannel is assumed to be the same. The dimensions of the channelare 0.2 x 1.2 µm, and different linear temperature gradients are applied to itswall. The flow is in the range of 0.002 ? Kn ? 0.2, that is, the slip flowregime. The governing equations, including continuity, Navier-Stokes and energyequations along with the velocity slip and temperature jump boundaryconditions, have been solved in the COMSOL Multiphysics software environment.Roughness is modeled using W-M fractal function, which is a completely randommodel. The effect of various fractal roughness parameters on thermal creep flowhas been investigated in detail, including relative roughness, 0 ? ? ? 4,fractal dimension, 2 < D < 1, and roughness density 1 ? Rd ? 5. Theresults show that the mass flow rate in rough microchannels is lower than thesmooth ones; And this decrease is more noticeable in higher Knudsen numbers.Therefore, in small Knudsen numbers and close to the continuum flow regime, theroughness effect is less important. For example, a high relative roughness of4% in near continuum flow with Kn = 0.002, leads to 15% decrease in mass flowrate; While the relative roughness as small as 0.5% in the Knudsen number of0.2 causes the mass flow rate to decrease by more than 27% compared to thesmooth channel. In general, it was observed that in different conditions, themass flow rate increases with the decrease of relative roughness, but there isa limit beyond which the flow behavior becomes independent of the roughnessheight, that is ? = 1%. So that, in the relative roughness of less than 1%, theflow is independent of the roughness parameters and the mass flow rate remainsalmost constant. In addition, it was found that the increase in roughnessdensity strongly reduces the mass flow rate, so that at high densities (Rd =5), the effect of thermal creep flow almost disappears. These last two featuresare specific to thermal creep flow and are not seen in pressure-driven andshear-driven flows.

   Abstract:    Ti-6Al-4V alloy with good tribological properties, low elastic modulus, high strength to weight ratio and Co-Cr-Mo alloy with excellent corrosion and abrasion resistance are used as metal biomaterials in artificial joints. In this study, the biocompatibility of the bimetallic system of Co-Cr-Mo and Ti-6Al-4V alloys, which are connected to each other through the transient liquid phase (TLP) process was evaluated. In this study, samples without coating and with hydroxyapatite coating were evaluated. The Phase composition, coating microstructure, corrosion resistance, metal ion release rate and cytotoxicity of samples were examined by using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Polarization, Inductively Coupled Plasma (ICP) and MTT tests. The results showed the presence of uniform and nanometer coating on the coated samples. Examination of corrosion resistance in SBF solution and blood serum showed that CT1 sample without coating had optimal resistance (icorr = 1.01 ?Acm?2 in serum solution and icorr = 1.25 ?Acm?2 in body simulation solution) and also the resistance of coated samples It is much more desirable than uncoated samples and the best result was related to HAp-CT1 sample (icorr = 0.1 ?Acm?2 in serum solution and icorr = 0.08 ?Acm?2 in body simulation solution). The results of ICP test showed that the release rate of ions in 7, 14, 28 days was less than the allowable limit. By performing cytotoxicity test, it was observed that the death rate of cultured cells on the samples within 3 days was a desirable value and close to the control sample and had a significant difference of p <0.05. In addition, cell growth on CT1 sample increased during 3 days, which indicates the optimal biocompatibility of CT1 sample compared to other samples. The results of tests performed in this study showed that the samples have good biocompatibility and the best result is related to CT1 sample. It was also observed that the hydroxyapatite coating applied on the samples significantly increased the biocompatibility rate. Key Words: TLP bonding, Biocompatibility, Corrosion Resistance, Metal Ion Release, Cytotoxicity.

Choosing an optimal filteration system can reduce operating, repair and breakdown costs in many industries. If the suspended particles in the fluid are magnetic ones, magnetic filters can be used to separate them. Since internal magnetic filters are not able to separate FeS particles and other sub-micron particles, the use of high gradient magnetic filters is suggested as a solution. An important parameter in evaluation of these filters is the rate of adsorption of suspended particles in the liquid. Therefore, in this research, with the aim of COMSOL simulation software, the amount of particle adsorption and the effect of effective parameters on this parameter have been investigated. In both two-dimensional and three-dimensional simulations, a transverse configuration with a constant matrix diameter and a constant magnetic flux density is used. Important parameters of this research are the Reynolds number of the flow, the transverse distance of the rod matrices and the particle diameter. In three-dimensional analysis, according to the given variable parameters, the horizontal distance of the matrices and Reynolds number play an important role in the amount of particle adsorption, so that for horizontal distances greater than H = 1.4, the particle adsorption rate is significantly reduced, and the percentage Particle absorption is below 27%. It was observed that changing the particle diameter has less effect on the particle adsorption rate. The highest particle adsorption in the fluid occurs with the magnetic field strength of 1 Tesla with a rectangular arrangement for the horizontal distance H = 1.4 and the Reynolds number Re = 2, which has an adsorption rate of about 35%. The absorption rate of particles in the three-dimensional state is approximately one-half that of the absorption in the two-dimensional state. This can be explained due to the fact that all variables in two-dimensional and three-dimensional simulation were the same. Therefore, the same number of particles is considered in both geometries leading different values of adsorption.   

  در پايان­نامه حاضر جريان پايا و گذراي خون در مدل

در اين مطالعه عددي، اثر شكل نانوذرات بر روي عملكرد حرارتي-هيدروليكي نانوسيال آب-آلومينا در هيت سينك داراي ريز مجراها با هندسه­هاي مختلف براي خنك كاري پردازشگرهاي الكترونيكي مورد مطالعه قرار گرفته است. اين مطالعه، براي پنج شكل نانوذره پلاكتي، تيغه­اي، مكعب مربع، بيضوي و استوانه­اي در چهار عدد رينولدز 400، 800، 1200 و 1600 در چاه گرمايي داراي ريزمجرا­ها با چهار مقطع دايروي، مثلثي، بيضوي و شش ضلعي انجام شده است. غلظت نانوسيال ثابت و مقدار آن برابر با 1% در نظر گرفته شده است. در اين مطالعه مشاهده شد كه هيت سينك با مقطع مثلثي بيشترين ضريب انتقال حرارت جابجايي را ايجاد مي­كند، و پس از آن، هيت سينك با مقاطع بيضوي، شش ضلعي و دايروي به ترتيب موجب ضرايب انتقال حرارت بزرگ­تري مي­شوند. همچنين، نانوذرات با شكل پلاكتي بيشترين افت فشار را ايجاد مي­كنند، و پس از آن، نانوذرات با شكل­ها­ي استوانه­اي، تيغه­اي، مكعب مربع و بيضوي به ترتيب موجب افت شار بزرگ­تري مي­شوند. در نهايت با ارائه يك پاراكتر مناسب (FoM) كه معرف نسبت افزايش نرخ انتقال حرارت جابجايي به افزايش افت فشار است، ميزان بهره­وري انرژي مورد ارزيابي قرار گرفته است.   

Abstract    Industrial processes that involve the heating and cooling of a variety of fluids flowing through the ducts are very extensive and today represent some of the most common and important processes in engineering. Actually, in heat engineering, forced convection is probably one of the most effective and widely used heat transfer tools. Metals in their solid form have much higher thermal conductivity than fluids, which is why it is expected that fluids containing metallic suspended particles or metal oxide will have higher thermal conductivity than pure fluids. In the present work, the effect of magnetic field on the fluid flow and heat transfer of a nanofluid in the tube is experimentally studied, and the nanofluid is a type of Fe3O4   magnetic nanofluid with distilled water base fluid. After designing the experimental apparatus, experiments conducted to investigate the effect of the main operating variables such as voltage applied to an electric field applied with an alternating current (V), nanofluid concentration (C) and the intensity of the inlet fluid flow to the sub-field (Q) on the difference between the inlet and outlet temperature of the nanofluid. The channel crossing was selected based on the design of the experiments using response surface methodology based on the Box-Behnken model. The values of the variables in the study of the effect of applied voltage are 40, 80 and 120 volts, concentration of nanoparticles in solution of 0, 0.02 and 0.04   gL   and fluid flow intensity of 180, 360 and 540 L

  شبيه­سازي جريان­هاي چند فازي و مطالعه نشست ذرات

چكيده اين پژوهش به بررسي عددي تاثير امولسيون حاوي مواد تغيير فاز دهنده ميكروكپسول شده بر روي انتقال حرارت جا بجايي در جريان آشفته، درون يك لوله افقي با شرط مرزي شار حرارتي ثابت مي پردازد. براي اين منظور، امولسيوني بر پايه آب حاوي غلظت هاي مختلف ميكروكپسول با هسته ميريستيك اسيد به عنوان ماده تغيير فاز دهنده بررسي شد. همچنين تاثير غلظت ميكروكپسول ها بر روي عدد ناسلت ، ضريب هدايت حرارتي، ضريب اصطكاك و دماي لوله مورد مطالعه قرار گرفت. براي انجام تحقيقات، مسئله شامل لوله و شار ثابت و امولسيون تغيير فاز دهنده در نرم افزار كامسول شبيه سازي شد . نتايج نشان داد كه افزودن ميكروكپسول هاي تغيير فاز دهنده به آب منجر به افزايش عدد ناسلت، ويسكوزيته و انتقال حرارت جابجايي در تمامي رينولدزها مي شود . همچنين مشخص شد با افزايش كسر حجمي اين افزايش همچنان ادامه دارد اما ضريب اصطكاك هم افزايش مي يابد كه منجر به ايجاد اختلاف فشار مي شود . در اين پژوهش علاوه بر موارد گفته شده مقدار ضخامت ميكروكپسول ها نيز مورد بررسي قرار گرفت كه مشخص شد با كاهش اين ضخامت با بيشتر شدن حجم ماده تغيير فاز دهنده، ميزان اثرگذاري امولسيون بر انتقال حرارت هم افزايش مي يابد .   

Numerical Study of Magnetic Field Effect on Convection Heat Transfer of Nanofluid Flow in a Microchannel  

  Drug delivery within the human body has a significant role in the treatment of many diseases. There are different methods for tra  orting a pharmaceutical compound to a specified part of the body among which magnetic drug targeting is of great attention.   A magnetic drug delivery system utilizes the magnetic field to tra  ort the magnetic nanoparticles as a means of a delivery vehicle. Therefore, it is possible to control the delivery of the drug in such a way that the particles of the drug to be focused adequately where necessary. This will accelerate the recovery of the disease and also prevent the destruction of healthy tissues by the drug. Cardiovascular diseases are one of the major causes of deaths of women and men in recent years which have different types. One of the most common cardiac diseases is abdominal aortic aneurysm. In this disorder, due to the weakening of the vessel wall and blood pressure, the aortic vessel in the abdominal region expands and may lead to tearing of the vessel. Usually, treatment of this disorder is aggressive and has a high risk. But an alternative approach based on embolization of aneurysm, brought up recently seems to be a cure for this disease. In this method, aneurysm region will be targeted by particles of demanded drug, using an external magnetic field. So the pressure on targeted vessel wall will reduce. In this thesis, the three-dimensional transient flow of blood and transfer of drug are simulated with Eulerian-Lagrangian approach in the region of abdominal aorta vessel suffering from an aneurysm. According to the physics of the problem, the oscillating velocity at the inlet with non-Newtonian fluid are considered for the blood flow and the effect of aneurysm geometry, magnetic field and specifications of drug particle are studied. The results indicate that an increase in the size of an aneurysm, vertical distance between aortic vessel and magnetic source and Reynolds number leads to a decrease in the efficiency of drug absorption. At the other hand increasing the strength of magnetic field, size of particles and magnetization of nanoparticles leads to increase in the capture efficiency. These findings can be used to design and develop the drug targeting systems for the human body.Keywords: Magnetic drug targeting, abdominal aortic aneurysm, magnetic nanoparticles, Eulerian-Lagrangian approach, non-newtonian fluid

  This thesis examines the numerical and experimental performance of a metal foam heat sink in the free convection heat transfer. Metal foams are porcelain materials that used recently in the wide range application. This welcome is due to the appropriate thermo physical properties such as high volume ratio and high thermal conductivity. They are very lightweight because of their high porosity (0.9 and further).   The specimen used in this experiment is an aluminum foam (13 mm × 40 mm × 40 mm) of 92% porosity with 10 ppi. The experiments were carried out for heat sink inclination position of 0 °, 30 °, 60 °, 90 ° and 4, 8, 12, 16 watt power input. Numerical simulation was performed by finite element method and commercial software Comsol Multiphysics5.2. The heat transfer and fluid flow in the metal foam is expressed in terms of the macro volume theory based on the local thermal non-equilibrium condition (LTNE) for the energy equation. In this work, effect of foam geometric parameters, foam height, heat sink inclination angle and base temperature on the thermal performance of metal foam was investigated. The experiments results, show that the thermal performance of heat sink with increasing input heat flux decreases. For power input of 16 watts, the highest Nusselt number belong the inclination of 60 degrees (25.75).Comparison of thermal performance between horizontal and vertical heat sink indicates that the performance of horizontal heat sink is better than the vertical. The results of the numerical model show that the highest mean Nusselt number for all foam samples are in the horizontal position. It can be concluded that the average Nusselt number decreases with increasing porosity, and increases with decreasing in pore density. Influence of metal foam pore density of on the Nusselt number shows that in the samples with a 10 ppi and ppi 20 do not differ greatly, but the specimen with ppi 5 has a better performance. Comparison of Nusselt number in vertical(25.29) and horizontal(30.94) heat sink with 0.92% porosity and 5 ppi show that the mean Nusselt number in the horizontal position is %22.34 more than the vertical position. Comparison of Nusselt number of a metal foam heat sink ( 0.92% porosity and 10 ppi) with a flat plate in the horizontal position at the same base temperature (97.7 ?) indicated that the Aluminum metal foam increasing Nusselt number by %62.59. mean Nusselt number in the horizontal upward position is %29.52 more than the horizontal downward position

  موضوع بهبود كيفيت صدا امروزه به يكي از موضوعات مهم و اساسي روز تبديل‌شده است .ازاين‌رو بهبود گفتارهاي آغشته به نويز يكي از موضوعات مهم در حوزه پردازش سيگنال است و در موارد بسياري مثل تشخيص صدا، شناسايي احساسات صوتي و...كاربرد دارد. تضعيف نويز به‌نحوي‌كه اختلالي در سيگنال اصلي به وجود نياورد يك چالش مهم براي بهبود صدا محسوب مي‌شود. روش‌هاي مختلفي براي كاهش نويز ارائه‌شده‌اند كه ازجمله روش‌هاي پايه مي‌توان به روش تفريق طيفي ، تبديل موجك، و...ساير موارد اشاره كرد. موضوع تحقيق اين پايان­نامه نيز بررسي نويز موجود در سيگنالِ گفتار، حذف و يا كاهش آن نويز ازسيگنال گفتارِنويزي و ايجاد بهبود در سيگنال‌هاي گفتارِ آغشته به نويز مي­باشد.در اين پايان­نامه دو   روش جديد براي كاهش نويز موجود در سيگنال گفتار نويزي ارائه داده ايم . در روش اول ، يك روش تخمين نويز براي نويزهاي غير ايستان همراه با اعمال تبديل موجك بر روي سيگنال و استفاده از الگوريتم بهينه‌سازي گروه ذرات با رفتار كوانتومي،را به صورت تركيبي با روش Bayesian ارائه داده‌ايم تا نويزهاي موجود در سيگنال نويزي را حذف كند و سيگنال بازيابي شده به سيگنال اصلي نزديك‌تر باشد.در روش دوم نيز با اعمال تبديل موجك بر روي سيگنال و تركيب آن با روش SMPR   روشي جديد براي كاهش نويز ارائه داده ايم. روش­هاي پيشنهادي نسبت به روش‌هاي موردتحقيق در اين پايان­نامه بهتر عمل مي‌كنند و منجر به كاهش نويز از سيگنال با كمترين اعوجاج مي‌شوند.

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Aerosols are very small solid particles or liquid droplets suspended in a gas phase. It is very important to study aerosols evolution and its relevant processes including coagulation, deposition, condensation, and source reinforcement. It seems even more essential in issues such as nuclear reactor containments contamination and its environmental effects. On the other hand, Analytical solution of the governing aerosol evolution equations is not possible except in some limited cases. In this research direct simulation Monte Carlo (DSMC) method is employed to develop a numerical computer code which simulates coagulation and deposition processes in multicomponent aerosols with different densities. The coagulation and deposition processes are simulated based on Brownian motions and diffusion of particles, respectively. The effects of gravity are considered for both processes as well. Sectional method, which is the common technique in simulation of aerosols evolution, is used to validate the ability of our DSMC code in modeling coagulation and deposition processes. The comparison results in a well agreement between two methods. Furthermore, the evolution of nuclear aerosol of Uranium dioxide enriched with water particles is investigated using the validated DSMC code. The Uranium dioxide particles, ranged from 0.01 to 0.04 micrometers in diameter, are distributed in a cubic repository of one meter edge length. Then water particles are added to the aerosol and the evolution of Uranium dioxide particles including mass distribution variations as well as deposition and coagulation of suspended particles are studied. The water particles, which have the same size in each study, are ranged from 0.012 to 0.551 micrometers in diameter. It is observed that increasing the water particles diameter results in decrease of uranium dioxide particles deposition; such that for water particles with mean diameter 0.55 micrometers, the uranium dioxide particles are mainly suspended. On the other hand, due to coagulation of small particles over the time, remaining suspended particles have much larger diameters (70 times greater than initial size in average). These features can be beneficial in many ways such as tra  orting and deposition controlling of aerosols as well as using larger hole filters (less flow restriction) in case of air purification of nuclear repositories. Finally, taking a closer look at the deposition process, an estimated relation is used to improve the simulation of the coagulation. We call this method modified deposition rate DSMC in contrast to common DSMC. This modification results in more realistic simulation with completely different results compared to common DSMC. Another disadvantage of the prevalent DSMC is using estimated deposition rates in modeling diffusional deposition which does not take advantage of the prominent feature of the DSMC method that is particle tracking. However, simulating diffusional deposition by means of estimated deposition rates fail to use the ability of DSMC method in particle tracking. Therefore, a new scheme for simulation of diffusional deposition is proposed which is based on movement and position of particles and hence more accurate. The results of this method are close to modified deposition rate DSMC.

  در اكثر محاسبات مهندسي مكانيكبراي جريان­هاي در ابعاد معمول به­جاي تحليل پيچيده­ي اثرات واقعي ملكول­ها از يكفرض توزيع پيوسته ماده استفاده مي­شود و محاسبات جريان با اين فرض پيوستگي انجاممي­شود. اگرمتوسط مسير پويش آزاد ملكولي با كوچكترين طول مسأله هم­مرتبه باشد فرضپيوستگي ماده صادق نيست. براي تحليل اين جريان بايد از روش­هاي پايه­اي­تر مانندروش­هاي ملكولي استفاده كرد. در چندسال اخير با گسترش زمينه­هاي مكانيك سيالاتجريان در ابعاد ميكرو و نانو بيشتر مورد توجه محققين قرار گرفته است. جريان­هايگازي ميكرو و نانو به­واسطه­ي طول مشخصه كوچك­شان معمولا در محدوده­ي ناپيوستگيجريان قرار دارند. يكي از پركاربردترين روش­ها براي حل اين جريان­ها استفاده مي­شودروش ذره­مبناي شبيه­سازي مستقيم مونت­كارلو (DSMC) مي­باشد.اين روش در جريان­هاي با عدد نودسن بالا به­خوبي عمل مي­كند.اما مشكل اين روش در جريان­هاي كم­سرعت مشاهده مي­شود. نوسانات آماري موجود در روشDSMCمانع از شكل­گيري درست جريان در مواردي كه سرعت پايين است مي­شود. يكي از روش­هاييكه براي رفع اين مشكل ارائه شده است روش ذره­مبناي نگه­داري اطلاعات(IP) مي­باشد. در اين روش قوانين بقا (بقاي جرم، بقاي مومنتوم و بقايانرژي) مشابه تحليل­هاي ماكروسكوپي، در خصوص اطلاعات IPپياده مي­شود. در اين پايان­نامه اساس روش­ DSMC-IPبه­عنوان ابزار عددي و ذره­مبنا براي حل جريان­هاي گازي رقيق­شده ارائه شده است.كد DSMC2 توسعه داده شده و روش IP بهآن اضافه شده است. هندسه­ي مورد مطالعه ميكرومحفظه­ي مربعي با ديواره­ي متحرك مي­باشد.اين جريان به واسطه­ي گردابه­هاي موجود در آن جرياني پيچيده است.برهم­كنش بينملكولي با استفاده از مدل كره­ي سخت متغير مدل­سازي شده و همچنين از طرح برخورد SBT براي انتخاب جفت برخوردي استفاده شده است. جريان دما ثابت است وگاز تك اتمي آرگون به­عنوان سيال مدل­سازي شده است. نتايج به­دست آمده موفقيت روش IP را در رفع نوسانات چگالي، سرعت، تنش برشي و... را نشان مي­دهد.همچنين علاوه­بر رفع نوسانات موجود در جريان­هاي سرعت پايين، نوساناتي كه در جريان­هايبا نودسن كوچك ايجاد مي­شود را نيز برطرف مي­كند. روش IPعلاوه­بر رفع نوسانات، در كاهش هزينه­ي محاسباتي نيز بسيار مؤثر است. نتايج حاصلاز حل IP نشان مي­دهد كه موقعيت مركز گردابه­ي اصلي با افزايش سرعت ديوارهدر جهت حركت ديواره جابه­جا مي­شود و همچنين با كاهش عدد نودسن جريان مركز گردابهبه سمت بالا جابجا مي­شود.

  Over the past several years, different control methods have been presented to avoid hyper synchronization of neurons in various papers, Because this abnormal synchrony disturbs the function of the brain and causes the diseases Like epilepsy and Parkinson. The primary treatment of disease   is drug therapy. if drug   treatment is unsuccessful, other therapies are there such as surgery and stimulation of the damaged area. in the surgical procedure, the damaged area of the brain is destroyed , which will have many side effects. In the direct stimulation technique, due to permanent stimulation of the damaged area, surgical problems can be reversed. Since stimulating methods of feedback and non- feedback are mathematical equations and have no biological background,   tried to use astrocytic stimulant as a biological stimulant. Several studies have shown that the effect of astrocytes on the absorption or release of glutamate in the synaptic space, the storage of potassium ion, and the regulation of extracellular pH is necessary to maintain the correct level of irritability in the CNS. The impairment of this function can lead to an increase in the stimulation of the neurons and their synchronization with each other. The disorder of this function can lead to an increase in the stimulation of the neurons and their synchronization with another. Therefore, astrocytes can apply appropriate control feedback to regulate neuronal activity. In this study, we tried to investigate the biological stimulus ability   induced by the behavioral dynamics of astrocytes using analog circuit design. Because astrocytes play a major role in neurological interactions in the neurons synchronization and desynchronization , the above stimulant advantage can be considered as the biological basis based on the interaction between neurons and astrocytes. To simulate the behavior of neurons in diseases caused by super-synchronization of neurons, the biological network of the neuronal population is considered, and the suggested stimulatory ability is investigate in their desynchronization. Considering the many applications that digital systems have, the design of analog circuits continues to apply where digital equivalents can not perform their tasks well. For example, in applications that require very low power, such as medicine, implantable elements, and portable and lightweight devices, digital circuits may not be appropriate. Also, all the signals in the real world are analog, and these analog signals will never be substitutable. For this reasons, the proposed system   is designed with analog circuits and simulated in the HSpice software.Key words: synchronization, stimulation, astrocyte, neuronal population, analog circuit design.  

The bulk of energy consumption and greenhouse gas emissions are attributed to buildings. The heating of water required for buildings consumes a considerable amount of energy. As a result, the use of solar water heaters can play an important role both in the storage of fossil fuels and in reducing air pollution and emissions of greenhouse gases. Many factors affect the thermal and economic performance of solar water heater systems. In this thesis, a forced-circulation solar water heater system has been simulated with flat plate collectors as well as a evacuated tube collectors. Given that the performance of solar systems is inherently dynamic and tend to vary over time, simulation has been done dynamically. The main objective of this thesis is to study the effect of hot water consumption patterns on the thermal and economic performance of solar water heaters. In addition, by applying different patterns of water consumption, appropriate values of collector mass flow rate and volume of hot water storage tank are determined based on the achievement of the highest thermal performance of the system. Moreover, the appropriate values of collector area are determined to achieve the most economic performance of the system. The results show that by choosing the consumption pattern that is almost identical to the hourly variations of the solar radiation, compared to other consumption patterns, system achieves the largest annual solar fraction in lower ratio of tank volume to collector area. Furthermore according to the results the hot water consumption patterns can have a significant effect on both the annual life cycle saving and the pay back time of the system. On the other hand, due to the low radiation from 6 to 10 AM and the heat loss of the storage tank over night, the auxiliary energy required during these hours, increases. This, in turn, will increase the cost of energy supply to the auxiliary system as well as the solar systems pay back time. Substitution of hot water consumption patterns with flat plate collectors for those employing evacuated tube collectors might increase the annual life cycle saving to a remarkable extent.

Rotary Regenerative Air Preheater (RRAPH) is one of the main equipment for energy recovery in the steam boiler of the power plants. In the present study, Ljungstrom air preheater of the Bisotoun Thermal power plant has been investigated with the aim of optimizing its thermal performance. In this regard, with Computational Fluid Dynamics (CFD), three-dimensional simulation of the rotary air preheater was performed to solve the continuity, momentum and energy equations in porous medium. Considering the structure of the plates of the Ljungstrom matrix, the use of the porous medium assumption is acceptable. The results of simulation show acceptable accuracy in comparison with the experimental results which is achieved from Bisetoon power plant data. In this research, the effect of rotational speed on the efficiency of air preheater in variety of loads and mass flow rates for both without leakage and with leakage conditions was investigated. The results of the present study show that the impact of the rotational speed on the performance of RRAPH is in the range of 0.5 to 4 rpm, and after this increase in speed does not have a significant effect on efficiency. The present study also shows that leakage has a significant effect on reducing the efficiency of the RRAPH in all thermal loads and rotational speeds. In the following, the optimum rotary speed was studied in different loads, mass flow rate of air and flue gas. For this purpose, both without leakage and with leakage have been studied. Results show, the efficiency of the power plant was almost constant for various thermal loads, and performance is only increasing with increasing rotating speed. On the other hand, with considering leakage effect, the maximum RRAPH efficiency is related to the power plants nominal load (320 MW). One of the most important and limiting factors in increasing the speed of rotation is the dew point temperature forms acid. Therefore, in this study, this index was extracted for optimal rotary speeds in different thermal loads. In the following, the effect of material change on the efficiency of RRAPH was investigated. According to the results, for both without leakage and with leakage the best thermal performance is related to the stainless steel, which has the lowest thermal diffusivity, lowest thermal performance is related to the copper, which has the highest thermal diffusivity.  

  Usually pile foundatios in addition to vertical load, because of some reasons such as earthquake force, wind effects, sea waves and soil pressure affected under the influence of considerable horizontal forces. Although the applied load to pile foundations is usually a combination of vertical and lateral components, there have been few investigations on the behavior of piles subjected to combined loadings. In common methods of pile design, due to the complexity of the analysis of piles under combined load and interaction between them, the analysis of piles under combined load is ignored. This matter is acceptable if the lateral load applied to the piles was small but for lateral loads with larger quantities, study the effects of applied combined vertical and lateral loads seems necessary.In this study the influence of vertical loads on the   lateral response of a 3×3 group pile for piles used in Arvand jahan ara steel making plant located in khoramshahr that connected together by a concrete cap is studied through finite element analysis. The analysis focus on the three piles in the middle row of pile group. The response of piles to pure lateral loads was first evaluated and then the response of piles to combined loads is examined for different values of vertical loads. The soil profile contains five layers and the Mohr-Coulomb model was adopted to simulate the behavior of soil. The piles are modelled as Linear-elastic material.The results have shown that increases in horizontal soil stresses around the piles is the main affective factor in changing the lateral response of pile group under combined loads. The effect of vertical loads on the lateral response of piles depends on the pile position. The vertical loads lead to increase in the horizontal bearing capacity of piles and thus lead to more economical design of pile foundations. Bending moment and shear force values in the piles under lateral load shown that the values of these parameters also depends on the value of vertical loads applied to the piles.

This research discusses photovoltaic cell modeling with two diodes. With respect to the problem parameters and available equations, seven parameters were recognized as unknown parameters. The parameters were determined by descending numerical sequence. A mathematical model was created using governing equations and a model was coded and prepared in MATLAB. The code was validated and the results were compared with the credible works carried out in this field. After being ensured of the validity of the code, different parameters effective in current and power were discussed in a photovoltaic array. Finally, optimization of problem parameters was discussed. To determine the important and effective parameters, the literature was referred to. Studying the literature revealed that most of the studies discussed and optimized the seven parameters to maximize the power generation. Consequently, this study discussed model optimization using the determined parameters, adopting an appropriate change interval, and applying meta-heuristic algorithms. Genetic algorithm and particle swarm algorithm have been used commonly and have been effective in this field. Therefore, the two algorithms were used and their results were presented. The remaining section discusses and evaluates the results.It was concluded form the results for examining radiation parameters that the major parameters on radiation include geographic location, day of year, and ambient temperature. Efficiency and power generation improve with the parameters increasing. Maximum power increases up to 6 times with the amount of radiation increasing from 200 W/m2 to 1000 W/M2. (Figure 1-6 shows the changes.)The study of the amount of radiation on different days of the year determined that the amount of power on the first day of summer was higher because the amount of radiation was maximal. Ambient temperature increases on summer days. The temperature rise improves PV efficiency. Temperature variations from 20 to 40 indicate an increase of power generation from 27 to 83 watts, which represents a 3-fold increase. According to reference [61], it was selected for optimization of parameters and its proportional interval. The results of genetic algorithm show that a maximum power of 74.27 watts could be generated.

  AbstractIn this study, it was investigated the use of nano-silica heterogeneous catalyst in biodiesel production from canola oil. This catalyst was synthesized from wheat bran during acidic processing under controlled conditions. Wheat bran is an agriculture by-product which its burning is accompanied by environmental pollutants. This by-product contains high much amorph silica. Acidic processing of wheat bran and then thermal treating under controlled conditions in 700 C caused to nano-silica production with high area and with amorph structure. Nano-silica had high amount acidic sites. XRD analysis approved the synthesized nano-silica structure. The results for SEM showed that particles had spherical structure, regular and homogenous. The effects of four parameters including reaction temperature, catalyst concentration, molar ratio of methanol/oil and reaction time on biodiesel conversion was evaluated by response surface method. Molar ratio of methanol/oil was 99.01% under optimum conditions including 70 C, 3% catalyst weight and for 5 hours. The data for catalyst recovery showed that the prepared catalyst has renewability for 5 times which can be used as sustainable and economical catalyst for biodiesel production. Key words: wheat bran, nanosilica, biodiesel, canola oil, RSM optimization       

In this study, natural convection flow in a micro enclosure is investigated using direct simulation Monte Carlo (DSMC) method. Argon molecules are used for gaseous medium. The sidewalls of the enclosure are subjected to various boundary conditions including adiabatic, constant temperature and symmetry where symmetry boundary condition simulates the flow in a long channel. The aspect ratio of the enclosure is set to AS = 2. The lower wall is heated to temperature TH and the upper wall is cooled to TL while the thermal ratio is preset to rT = TH/TL= 0.1. Similar problem for macro-scale channels which is known as Rayleigh-Benard problem is widely investigate. However, the micro enclosure problem which classified as rarefied flow is still under study. The Knudsen number is assumed in the range 0.001 ? Kn ? 0.12 and a wide range of 0.2 ? Fr ? 10000 is studied for Froud number. The results show that the thermal creep effect has an important role in formation of convective rolls in the enclosure. Unlike the channel flow where no vortex will appear in adequate low or high Froud numbers (based on Knudsen number), in enclosures we have vortexes in all Froud numbers at all Knudsen numbers due to thermal creep phenomenon.   It is shown that the heat transfer rate is the same for channel and enclosure at very small or very high Froud number. However, for mediate Froud numbers heat transfer rate decreases in enclosure as where the side walls resist against convective rolls. The bounds for the values of high or low Froud number depend on the Knudsen number. Finally, the ability of SBT collision scheme in simulation of Rayleigh-Benard convective flow is evaluated in this study. Comparing to NTC scheme which is conventional collision scheme for DSMC method, it is shown the SBT scheme is accurate enough to simulate the Rayleigh-Benard instability flow.

يكي از مباحث مهم در جامعه امروزي كه دغدغه بسياري از كارشناسان و همچنين كاربران مي‌باشد بحث امنيت و تشخيص و تاييد هويت است. مردم خواستار اقدامات امنيتي بي­عيب، ساده و كاربرپسند هستند. بيومتريك، احراز هويت افراد براساس ويژگي­هاي منحصربفرد و متمايز كننده ، مقاوم و قابل­سنجش است كه بتواند جهت تعيين يا تأييد هويت افراد بكار رود. شناسايي از طريق بيومتريك، شناسايي يك فرد براساس صفات فيزيولوژي، رفتاري و شيميايي يك شخص است. تشخيص هويت از طريق بيومتريك مزاياي بسياري دارد و تاكنون روش­هاي مختلفي ارائه شده است. روش­هاي بكار رفته در هر دوره قوت و ضعف فناوري آن را به همراه دارد. در بين ويژگي­هاي بيومتريك مختلف استفاده از الگوي رگ دست افراد يكي از مناسب­ترين و قابل اطمينان­ترين خصيصه­هاي بيومتريكي مي­باشد كه ما در اين پايان­نامه به آن مي­پردازيم. سيستم­هاي تصديق هويت مبتني بر الگوي رگ دست شامل چندين مرحله مختلف از قبيل پيش­پردازش، استخراج ويژگي الگوي رگ­ها و تطابق الگو است. در سال­هاي اخير روش­هاي مختلفي براي هر كدام از اين مراحل ارائه شده است. در اين پايان نامه، تمركز ما بر روي استخراج ويژگي و بكارگيري توصيفگرهاي بافت تصوير و تركيب چند توصيفگر مي­باشد. به منظور استخراج ويژگي توصيفگرهاي الگوي باينري يكنواخت، الگوي باينري يكنواخت مستقل از چرخش و كوانتيزه ساز فاز محلي مستقل از چرخش به كار گرفته شده است. همچنين در روش پيشنهادي تركيب چند توصيفگر را نيز بررسي نموده ايم. در ادامه براي طبقه بندي تصاوير، سه طبقه بند متفاوت ماشين بردار پشتيبان، درخت تصميم و كا نزديك­ترين همسايه بكار گرفته شده است. براي ارزيابي دقيق روش پيشنهادي، از مجموعه داده PUT Hand Vein   كه خود شامل دو مجموعه داده از تصاوير رگ كف دست و رگ پشت دست است، استفاده شده است. پايگاه داده شامل 1200 تصوير رگ كف دست و همچنين 1200 تصوير رگ پشت دست است. همچنين پارامتر دقت طبقه بندي تصاوير و زمان محاسبات اندازه گيري شده است. نتايج بدست آمده از اجراي اين الگوريتم­ها و تركيبات مختلف آنها نشان مي­دهد كه بهترين الگوريتم تركيب الگوي باينري يكنواخت و كوانتيزه ساز فاز محلي است كه دقت اين روش در تصاوير رگ كف دست براي دست راست 99 درصد و براي دست چپ 33/ 99 درصد با طبقه­بند ماشين بردار پشتيبان بدست آمده است. در تصاوير رگ پشت دست براي دست راست مقدار دقت طبقه بندي 83/97 درصد و براي دست چپ 66/97 درصد با بكارگيري طبقه­بند كا نزديكترين همسايه بدست امده است. علاوه بر اين در مقايسه با روش هاي پيشين، نتايج بدست آمده از روش پيشنهادي بهبود دقت را نشان مي­دهد.  

  The present work is aimed at energy and exergy analysing of a IX-SAHP system considering the effects of the pressure drop associated with the ?ow of R134a refrigerant through the condenser, evaporator and connection pipes and the flow of Ethylene glycol through the collector, using Homogeneous method for two-phase pressure drop inside horizontal pipes. This system mainly employs a collector with a surface area of 5.5 m2, a hot water tank with the volume of 150 L, an electrical rotary-type hermetic compressor and a thermostatic expansion valve. The effect of various parameters, including solar radiation, ambient temperature, collector surface area, compressor speed and number of collector cover has been studied on the thermal performance of the system. The simulation results have good agreement with experimental results and they indicate that with the increase in ambient temperature (Ta) from -5 to 30 °C, for a given solar radiation of 700 W.m-2, the system COP and collector ef?ciency (?C) increases from 2 to 3.5 and from 35.8 to 58.8%, respectively. With the increase in radiation intensity (IT) from 350 to 1200 W.m2, for a given ambient temperature of 20 °C, the system COP increases from 2.1 to 5.5 and collector ef?ciency decreases from 71.4 to 45.6% and also with increasing ambient temperature, solar radiation and compressor speed, the pressure drop in the condenser, collector and evaporator increases.

  AbstractIn this thesis, a model has been introduced to simulate the capture efficiency of 3D high gradient magnetic filters for the separation of iron sulfide particles from the amine solution in the sweetening gas process. The geometry of the filter consists of a matrix of rods located in a channel with a square cross section. In order to study this problem, initially the Navier-Stokes equations coupled with Ampere equation are solved numerically in a 2D geometry. Having the flow field, the problem of particle capturing has been studied due to Lagrangian viewpoint and the effects of governing parameters including the particle diameter, fluid velocity and the geometrical parameters of the matrix have been investigated. Finally, the results of 2D analysis have been extended to simulate the particle capturing in a 3D filter. The 2D numerical simulations have been performed with COMSOL MULTIPHISICS 5.0 based on the finite element method and the extension of results to the 3D case has been carry out with proper code in MATLAB. This code interpolates or extrapolates the 2D results for any cases rather than those simulated in COMSOL. It has been demonstrated that the capture efficiency of filters with triangular configuration is higher than the rectangular one in the same conditions because the triangular configuration provides a better fluid mixing. However, the difference between capture efficiency of these two filters decreases with the increase in fluid velocity or distance between the matrices or decrease in particle diameter. Also, it has been demonstrated that the capture efficiency of these filters is directly related to the particles diameter and reversely dependent to the fluid velocity and the distance between the matrices. In addition, the performance of these filters are investigated in the case of non-uniform distribution of particles in the inlet. In order to demonstrate a useful graph, the performance contours of the 3D filter in the operational conditions are presented in terms of Reynolds number and the distance between the matrices. These counters show that the capturing efficiency of 60% will maintained when the dimensionless distance between the matrices is less than 1.2 independent of the Reynolds number.   Keywords: Magnetic filter, Capture efficiency, High gradient magnetic separation, Particle tracing

In this thesis, numerical simulation of fluid mixing has been performed for non-Newtonian flow under the effect of electric filed (Electroosmotic flow). This problem is of great importance as a frequent process in advanced and progressive technology of Lab-on-Chips and has numerous applications introduced in medical and biochemical areas. One of the major purposes of this field is to design high performance micromixers so that ideal mixing can be achieved in minimum time and energy consumption. In this study, the effects of governing parameters on mixing performance have been investigated in a flow field consisted of combined electroosmotic and pressure driven flows in presence of physical hurdles and zeta-potential heterogeneities. The simulations have been conducted for 2D geometry using finite element method by means of commercial code COMSOL Multiphysics 5.2a. Nernst-Planck equations have been used for the modeling of electric double layer (EDL) and the distribution of ions. The results indicate that several factors such as dilatant fluid behavior, adverse pressure gradient, zeta-potential heterogeneities as well as height of hurdles can have augmentative effects on the mixing performance. It is found that increasing the length of the hurdles has small effects on mixing performance while the location of the hurdles along the channel hardly changes the mixing quality. It is also seen that the effect of patches’ arrangement on the mixing is mostly depended on the magnitude of the zeta-potentials of the patches. The results showed that among the various effective parameters, the best choice for increasing the mixing quality is to increase the value of zeta-potential of the patches, because the mass flow rate passing the micromixer has no reduction and it is almost constant. This is a key characteristic because any reduction in mass flow rate is undesirable and deteriorates the performance of micromixer.

  Due to the growing need of the industry for energy and the increasing price of fuel and limited energy resources, it is significant of optimizing energy consumption and preventing its loss in industries. The exergy method is a powerful and effective tool for analyzing the energy system of industrial processes. The purpose of exergy analysis is to determine the location of exergy loss and its amount in a process. In this study, the exergy and energy analysis were carried out for amine sweetening unit of Ilam Gas Refinery. Since the temperature change of the environment plays a major role in the amount of waste and exergy efficiency of the components, in this study, the changes in these parameters have been investigated by changing the ambient temperature from 10 to 40 oC. According to energy analysis, most energy losses occur in air coolers, and both air coolers in this unit together causing 87% of energy dissipation. In this study, components are specified with the highest and lowest amount of exergy loss. The results of the exergy analysis show that the air cooler 1 at 10 °C and the filter 1 at 10 °C have the lowest and the highest exergy efficiency, respectively. At all temperatures, the highest exergy losses occur in the amine recovery tower and the lowest losses occur in filter 3. By increasing the ambient temperature, the maximum change in exergy efficiency occurs in air coolers.

همانند سازي نرم افزاري تراوش جداسازي غشايي گازهابا غشاء پليمري

  analyzing THE SMART BUILDINGS ON THE LOSS REDUCTION AND IMPROVING THE VOLTAGE PROFILE APPLYING TLBO