One of the important issues in excavation in urban environments is the monitoring of the pit wall, which, if not monitored accurately, can lead to irreparable loss of life and property. Pit wall monitoring is a vital aspect in geotechnical and civil engineering that can have significant effects on the safety and sustainability of construction projects. This study investigates the effect of time on changes in the shape and position of semi-deep pit walls using a total station camera and Plaxis software, using the Mohr-Columbus behavior, and emphasizes the importance of master monitoring and time-based analysis. By simulating real construction and loading conditions in Plaxis software, the behavior of pit walls over time is analyzed under the influence of various factors such as soil type, loading, environmental conditions, etc. In this type of monitoring, by considering the effect of time in the analyses, more optimal solutions are provided for the design and implementation of excavation operations and will reduce potential risks. In this study, a project (under construction) during the semi-deep excavation operation (12.5 m) was considered, and with increasing excavation depth, ten reference points were examined as selected monitoring points, and with the information obtained from the monitoring, we modeled it in Plaxis software and examined the driving and resisting forces and the rupture wedge by considering the effect of time in the analyses. In this software, the different stages of pit construction are accurately modeled and the time changes in lateral pressures, settlements and deformations of the pit wall are examined. Among the outstanding results of the study, the following can be mentioned: 1- In time-dependent analysis, it always predicts a greater displacement than the instantaneous analysis. 2- The greatest deformation usually occurs at half the height of the pit wall. 3- The pause between excavation stages has a significant effect on increasing the deformation of the pit wall. 4- In soft fine-grained soils, creep behavior is very effective. 5- Field monitoring results are usually closer to time-dependent analysis than static analysis. 6- The speed of project implementation due to weather conditions is the main controlling factor of pit wall deformation. 7- Time-dependent analysis usually shows the actual likely failure pattern better.   

   با افزايش روزافزون تقاضاي جهاني براي انرژي و نگراني‌هاي زيست‌محيطي ناشي از مصرف سوخت‌هاي فسيلي، توسعه و به‌كارگيري فناوري‌هاي نوين انرژي‌هاي تجديدپذير بيش از پيش ضرورت يافته است. در اين ميان، سيستم‌هاي فتوولتائيك حرارتي (PVT) كه توانايي توليد هم‌زمان برق و گرما را دارند، به عنوان راهكاري مؤثر براي افزايش بهره‌وري انرژي و كاهش انتشار آلاينده‌ها مطرح شده‌اند. در اين پژوهش با استفاده از نرم افزار تجاري شبيه سازيANSYS Fluent ، به تحليل و ارزيابي عملكرد حرارتي يك سيستم PVT مبتني بر سيال خنك‌كننده پرداخته شده است. در اين مطالعه، تأثير پارامترهاي مهمي همچون شدت تابش خورشيدي، دماي محيط، سرعت باد، دبي جرمي سيال خنك‌كننده و فاصله هوايي بين پوشش شفاف و پنل فتوولتائيك بر عملكرد سيستم بررسي شده است. مدل‌سازي با استفاده از روش حجم محدود و الگوريتم SIMPLE انجام گرفته و براي افزايش دقت، از روش Second Order Upwind در گسسته‌سازي معادلات بهره گرفته شده است. شبيه‌سازي‌ها در دو اقليم متفاوت كرمانشاه (با آب‌وهواي گرم‌تر و خشك‌تر) و بخارست (با آب‌وهواي خنك‌تر و مرطوب‌تر) انجام شد تا تأثير شرايط محيطي به‌صورت مقايسه‌اي مورد ارزيابي قرار گيرد. نتايج نشان مي‌دهد كه عملكرد حرارتي سيستم PVT به شدت تحت تأثير شرايط اقليمي است. در كرمانشاه، به دليل دماي بالاتر و رطوبت كمتر، توان حرارتي سيستم حدود ?.? درصد بيشتر بوده و به ???? وات مي‌رسد، در حالي كه در بخارست توان حرارتي ???? وات محاسبه شد. همچنين، گراديان دماي شديدي در ناحيه انتقال حرارت از پنل به سيال خنك‌كننده مشاهده شده كه اين افت دما در اقليم سردتر بخارست محسوس‌تر است. تحليل توزيع جريان هوا در بالاي پنل‌ها نشان مي‌دهد كه جابجايي طبيعي نقش مؤثري در تهويه و كاهش دماي سطح دارد، اما در اقليم گرم‌تر، اتلاف حرارت تابشي سهم بيشتري از اتلاف حرارت كل را به خود اختصاص مي‌دهد. علاوه بر اين، نتايج حاكي از آن است كه انتخاب بهينه پارامترهايي مانند سرعت سيال، فاصله هوايي و خواص ترموفيزيكي مي‌تواند بازده نهايي سيستم را به طور چشمگيري بهبود بخشد. استفاده از سيال خنك‌كننده علاوه بر افزايش راندمان الكتريكي سلول‌هاي خورشيدي، امكان بازيابي گرماي جذب‌شده را براي مصارف گرمايشي فراهم مي‌كند. بنابراين، سيستم‌هاي PVT در صورت طراحي بهينه و كنترل دقيق شرايط عملياتي، مي‌توانند به عنوان راهكاري كارآمد براي تأمين همزمان انرژي الكتريكي و حرارتي در ساختمان‌ها، به ويژه در مناطق خشك و نيمه‌خشك، نقش مهمي در توسعه پايدار و كاهش هزينه‌هاي انرژي ايفا كنند.

Abstract

In this numerical study, heat transfer and fluid flow in circular microchannels with porous and solid ribs were investigated. Water was used as the cooling fluid. A total of 23 circular ribs were analyzed across 8 porous and 6 solid cases in the microchannel. The rib volumes were kept constant across all cases, and in each case, increasing the inner diameter resulted in increased rib thickness. Due to the small size of the channel, laminar flow was used to avoid excessive pressure drop, with the Reynolds number ranging from 100 to 800. The Darcy–Brinkman–Forchheimer equations were applied to simulate the porous regions. The Nusselt number, pressure drop, and figure of merit (FOM) were calculated for all cases and compared. For the same inner diameter, solid ribs exhibited a higher pressure drop. The first solid case achieved the highest heat transfer among all cases. For the same inner diameter, porous cases demonstrated better FOM, with the first porous case having the highest FOM. This case was identified as optimal, as it provided satisfactory heat transfer without imposing excessive pressure drop on the system. The effects of porosity, permeability, and Al?O? nanofluid concentration were analyzed for the optimal case. Both solid and porous ribs improved the FOM compared to a ribless channel. For systems where both heat transfer and pressure drop are critical, porous ribs are a suitable choice. For systems where pressure drop is of greater concern, porous ribs are preferable. The third, fourth, and fifth solid cases, as well as the sixth, seventh, and eighth porous cases are recommended for systems prioritizing heat transfer performance.   

Abstract The islanding of interconnected power systems, which is also known as the isolation and breaking of power systems, is the last defense method to deal with the collapse of the system and prevent the occurrence of catastrophic events in the power network, which as a widespread control method is a comprehensive decision problem with There are many details and it is presented as an important part of corrective control strategies. After the occurrence of a major disturbance in a power system, if there is no suitable solution plan and model in time, this disturbance may lead to the total collapse of the system. Islandization of power systems means determining the correct points of isolation of the integrated system into a number of smaller islands if maintaining the integrity of the system is not possible. The aim of this thesis is to provide a method to predict the appropriate time for applying controlled islanding in the network by means of indicators based on the relationships between the generator harmonic groups. The defined indicators can predict the weakening of security and fragility of the network in the context of the dynamic behavior of the system and as a result the islanding of the network with high speed and accuracy and in a timely manner. The IEEE 39 bus network has been used to obtain the critical limit of the introduced indicators in a timely manner and to predict the appropriate time for islanding in a timely manner. The results obtained from the dynamic simulation indicate that the controlled islanding at the right time can prevent the occurrence of consecutive incidents, global blackouts and crises in the network.   

  سيستم مهاربندي كمانش تاب با استفاده قابليت استهلاك

   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

   Experimental study of the effect of using phase change materials in heat pipe condensers for cooling of electronic components

For many years, the separation of ethylene (C2H4) from ethane (C2H6) for the production of pure ethylene for industrialpurposes has been of great importance. The separation of ethylene from ethane is a vital process in the industry, which requires high-purity separation for ethylene to produce high-quality final products. The pure ethylene obtained from this process is used as an important raw material in the production of plastic, rubber, and other chemical products. The process of ethylene separation acts as a fundamental basis for the petrochemical industry and is of great importance in meeting global industrial and economic needs. Cryogenic distillation is the main technology for separating ethylene and ethane, which is used due to the close boiling point of ethylene and ethane (187.6 K for ethane and 169.5 K for ethylene) under very low temperatures and high pressures. However, this process is very costly in terms of investment and energy consumption in the petrochemical industry. Therefore, various alternative methods have been investigated to increase its efficiency and reduce the associated costs. One ofthe significant limitations of these alternative methods is their limited selectivity, making them incapable of serving as a complete replacement for cryogenic distillation. Nevertheless, internal absorption processes can potentially serve as a suitable substitute for cryogenic distillation. The main objective of this study is to investigate the amount of pure ethylene and ethane gas absorption by CuAlCl4 absorbent in a toluene solvent. In this study, the effect of various parameters such as concentration, temperature, and pressure on the amount of absorption of these two gases has been evaluated. Finally, we found that the current process shows very good selectivity between ethylene and ethane. Additionally, there is a trade-off between the absorption and selectivity of ethylene. With increasing pressure, the capacity of ethylene absorption increases, but the selectivity decreases. At low pressures, the selectivity increases, but the capacity decreases. The maximum selectivity of ethylene to ethane is achieved at the lowest possible pressure, but the low capacity of ethylene at low pressures is a limiting factor for optimal process design.

   Identification of two-phase flows and its Taylor bubble characteristics is one of the most important parameters designing industrial installations for intermittent gas-liquid two-phase flow. Also, it is important to know the characteristics of two-phase flow in order to improve the exploitation of oil wells and to optimize the process of maintenance and repair of flow transmission lines with the purpose of cleaning pipelines along with reducing its costs in the oil and gas industries and in chemical and electronic chip cooling industry. The purpose of this research to analyze bubble flow patterns, achieve two-phase flow patterns of water and air using numerous experimental tests and investigate the effect of pulsating gas flow on the characteristics of the Taylor flow field (Taylor bubble length and velocity) under different two-phase inlet conditions air and water done in the form of an upward parallel flow. The range of studied apparent velocity Gas and Liquid phase is 0.12-0.28 m/s and 0.05-0.25 m/s, respectively, and the pulsating gas flow frequency is 0.25-0.4 Hz. In this study, by examining more than 100 different apparent velocities for the phases, three patterns of bubble, slug and churn were observed and a map of the two-phase flow pattern of water and air was drawn. Also, the effect of pulsating gas flow on the length of the Taylor bubble was investigated in 150 different experiments, and the results of this study showed that with the increase of the pulsating gas flow and the frequency, the stability of the Taylor bubble flow increased and the length of the Taylor bubble decreased significantly. So that at the frequencies of 0.25, 0.5, 1, 2 and 4 Hz, respectively, the maximum bubble length was observed at the liquid velocity of 0.12 m/s and gas velocity of 0.25 m/s are 455.5, 367, 313.1, 286.3 and 244.2 mm.   Also, at a constant frequency, the length of the Taylor bubble increases with the increase of the apparent velocity of the gas phase. For example, at a constant frequency of 1 Hz and a liquid velocity of 0.12 m/s, the bubble length increased from 147.8 mm to 1.313 mm when the gas velocity increased from 0.10 to 0.25 m/s. In addition, in this research, with the help of image processing, the movement speed of the Taylor bubble was measured and determined for 15 different apparent speeds using the speed measurement technique. Comparison of the obtained linear equation with previous studies showed that the relationship has a good fitting accuracy. The results of the present work proves that the pulsating gas flow technique enables the control of the gas-liquid Taylor bubble flow pattern and the stability of the motion of the Taylor bubbles, which will be very useful for future industrial applications in gas-liquid reactions.

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.   

One of the types of steelshear wall is the composite shear wall, which consists of a steel sheet and a layerof reinforced concrete. This type of shear wall is used in high and mediumheight steel structures to improve the performance of the structure and controlvibrations during earthquakes. On the other hand, one of the serious threats insteel pasture structures is fire. Therefore, the necessity of investigating thebehavior after fire in steel structures with shear walls is felt more thanever.After studying theprevious researches, the scientific gaps and scientific challenges wereidentified and based on that, the purpose of the research was determined. Themain goal of this research is to investigate the seismic behavior of thecomposite shear wall with reinforced concrete cover at different temperaturesin the first step and to compare its behavior with the shear wall withoutreinforced concrete cover in the second step. For this purpose, three types ofsteel frame, including steel frame without shear wall (reference specimen),frame with steel shear wall without reinforced concrete cover and frame withsteel shear wall covered with reinforced concrete were studied in the conditionsbefore and after the fire.   Thetemperatures selected in this research are 25, 350, and 700 degrees Celsius,and the numerical models are subjected to cyclic loading, and the seismicbehavior, including the ultimate strength, energy dissipated, is compared andinvestigated. Also, the thermal stress caused by the fire is also evaluated.The results of thisresearch show that at all temperatures, the composite steel shear wall hasbetter seismic behavior than the steel shear wall, so that at 25 degreesCelsius, the ultimate strength of the frame with steel shear wall and the framewith composite shear wall It is 12.8 and 24.6 times of the reference sample(steel frame without steel shear wall), respectively. As a result oftemperature increase from 25 to 700 degrees Celsius, in the frame with steelshear wall, the ultimate strength has decreased from 483 to 11 tons, while inthe frame with composite shear wall it has decreased from 925 to 124 tons.Also, the presence of reinforced concrete cover on the steel sheet at alltemperatures has increased the cumulative dissipated energy. In other words,the presence of reinforced concrete coating on the steel sheet has protectedthe frame with shear wall against fire.  

Cracking in concrete is alimiting factor for the inelastic performance of the structure, so byconfinement the concrete, its strength can be increased. Due to the highcompressive strength of high performance concretes, it is one of the well-knownmethods in increasing the strength of structures that has always beenconsidered by researchers and designers. Due to the need to respond to somedesign issues and the lack of uniform design criteria in the regulations, inthis research, an attempt has been made to test high performance concrete(UHPC) and by incorporating confinement conditions, compressive strength andstress diagrams. The aim of this thesiswas to experimental investigation the compressive behavior of ultra-highperformance concrete confined with FRP. For this purpose in this research, atfirst, reliable sources and new articles have been studied and reviewed. In thenext step, based on reliable sources, the mixing plan for normal concrete andhigh performance concrete (UHPC) is prepared. In the final step, 20 cylindricalsamples with different confinement conditions were subjected to compressiveloading and their stress-strain diagrams were evaluated.The results of thisthesis shown that, the ultimate strength of the third pattern was higher in thesample with NC concrete. Therefore, that in samples N25L1P3 and N50L1P3,respectively, the ultimate strength was 14% and 59% higher than the referencesample (N). While the second pattern has the lowest ultimate strength.5- The ultimate strengthof the third pattern was higher in the sample with UHPC concrete. So that inU25L1P3 and U50L1P3 samples, the ultimate strength was 394% and 433% higher thanthe reference sample (N).Also, increasing thepercentage of confinement in samples has increased the dissipated energy. Thelowest dissipated energy is related to the reference sample (N) and is equal to3.77 Kn.m, and the highest dissipated energy is related to the N100L1 sampleand is equal to 24.88 Kn.M. In addition, among the samples with UHPC concrete,the lowest dissipated energy corresponds to sample U and is equal to 10.28Kn.m, and the highest amount of dissipated energy is related to sample U100L1and is equal to 44.42 Kn.m.  

ا رشد پلتفرم ها و برنامه هاي كاربردي شبكه هاي اجتماعي آنالين، روزانه مقادير زيادي محتواي متني توسط كاربر به روشهاي مختلف مانند نظرات، تحليلها، اخبار و پيام هاي متني كوتاه ايجاد مي شود. در نتيجه، كاربران اغلب براي استخراج اطالعات مفيد در مورد موضوع مورد بحث اين گونه محتوا را پالش برانگيز ميدانند. امروزه براي 1 استخراج راحتتر اطالعات مفيد از روشي به نام استخراج موضوع استفاده ميكنند. استخراج موضوع با اسستقاده از يك سري محاسبات آماري خالصه يا موضوع اصلي سند مورد نظر را از متن بيرون ميكشد، كه با اين كار ميتوان با مشكالت كمتري به تجزيه و تحليل اسناد پرداخت. در اين پژوهش قصد داريم با استفاده از روشهاي يادگيري عميق همچون)DNN,LSTM )يك شبكه يادگيري عميق جهت استخراج موضوع با دقت بيشتر از كارهاي انجام شده در اين زمينه طراحي كنيم. ديتابيسي كه در اين پژوهش بر روي آن كار خواهيم كرد ديتابيسي متني شامل اخبار است. كه در ابتدا با استفاده از تكنيكهاي پيشپردازش متن )تبديل كردن تمامي حروف موجود در دادههاي متني به »حروف كوچك« )letters Lowercase ،)پاك كردن عالئم نقطهگذاري )Punctuations ،)پاك كردن »كلمات بي اثر« )Stopwords ،)مصدر سازي كلمات)Stemming ) )عمليات نرمل 2 سازي را انجان داديم. از LDA بعنوان روش يادگيري شبكه استفاده ميكنيم به بياني واضح تر شبكه يادگيري عميق بر اساس تكنيك استخراج موضوع LDA كار خواهد كرد. نتيجه اين پژوهش دقت بشتر شبكه يادگيري نسبت به شبكههاي ساخته شده در كارهاي پيشين است كه توانستهايم دقت شبكه بر روي ديتابيس مورد نظر را نسبت به آنها بيشتر كنيم.  

  Usually, most of the destructive earthquakes that occurred in Iran and left many casualties and damage were near earthquakes. Earthquakes such as Manjil 1369, Bam 1382 and Sarpol-e Zahab 1396 are examples of these near-field earthquakes that occurred in Iran. Determining the performance and evaluating the structure and its components is important to determine the seismic capacity and requirements. Due to the fact that most instruments enter the nonlinear area during moderate and severe earthquakes, so estimating the exact capacity of the structure requires the use of more efficient methods in the science of structural analysis. In the analysis and design of structures according to the type and manner of application of loads on the structure and the philosophy of seismic design and the occurrence of nonlinear behavior under the forces on the structure due to earthquakes, in order to determine the exact behavior of the structure is necessary. Different nonlinear dynamic analyzes are used. Dampers are considered as the best method to control and improve the behavior of structures as well as to improve the performance of structures. The main purpose of the thesis is to investigate the seismic performance of flexural frames of reinforced concrete equipped with rotary friction dampers. The results showed that the coefficient of increasing resistance for medium flexural frames equipped with dampers was obtained according to the overlay analysis of 2.63 and based on nonlinear dynamic analysis of 2.90. The obtained ductility coefficient for flexural frames with medium ductility equipped with dampers according to the cover analysis is 2.52 and based on nonlinear dynamic analysis is 3.15. The behavior coefficient for medium bending frames equipped with dampers was 6.56 according to the cover analysis and 8.83 according to the nonlinear dynamic analysis. The coefficient of increasing resistance decreases with increasing number of classes, while the coefficient of behavioral ductility has the opposite. The damper improves the three factors of increasing strength, ductility and modifying the response (coefficient of behavior) according to nonlinear dynamic analysis, while the other analysis of the ductility factor for short structures shows the opposite.

   Abstract Like other steel systems, steel moment frame system is used for various reasons such as high manufacturing speed, high strength, ductility, etc. The significant advantage of this system is the architectural considerations that make it possible to open the openings. This system analysis and design process assumes that the connections have a complete rigid behavior, while this assumption may not be accurate, and the connections’ rigid behavior assumption will cause errors in the analysis and design results.    This paper examines the effect of semi-rigid connections on the behavior of steel moment frames to determine the structure behavior factor. Hence, we analyzed and designed rigid steel moment frames, with different openings and floors, following 2800 regulations and topic 10 of the National Building Regulations. Then, we conducted pushover analysis on the frames and plotted the capacity curve of the frames, once assuming the rigid connection and then considering the nonlinear behavior of the connection. We used two springs with zero length at the end of the beams with the anchor-connection curve to model the connection behavior. The results show that for frames, assuming a rigid connection, the calculated behavior factor is close to 5, which is the recommended value for this structural system in Regulation 2800. In semi-rigid structures, the values ??of the behavior factor are in the range of the behavior factor of the rigid structure.    Keywords: Rigid Connections, Semi-Rigid Connections, Steel Moment Frames, Nonlinear Static Analysis, Extensive and Concentrated plasticity

   Abstract: this paper presents a technique for low noise figure reduction of low-noise-amplifier. The proposed LNA is designed in a current reuse technique that offers lower noise figure. Also, using inductor as a gate inductor reduces the effect of the input parasitic capacitance on the noise figure and provides a good matching at the input and output of the LNA. It shows that the proposed technique reduces significantly the noise figure and improves the matching. The proposed LNA is designed in 0.18 ?m process with 1.5 V supply voltage and simulated cadence software. The simulation results show that The LNA achieves voltage gain of 13.3 dB, noise figure of 2.3 dB, and S11 less than ?10 dB, while consuming only 8.1   mW. The layout schematic occupies 0.812 of chip area.

در اين پايان نامه، يك تقسيم كننده توان ويلكينسون ارائه شده است. كه در ان علاوه بر دارا بودن دو باند كاري داراي حذف هارمونيك نيز مي باشد. اين تقسيم كننده با كمك رزناتتورهاي متقارن و استاب هاي بلند و كوتاه طراحي شده است.اولين فركانس كاري اين (WPD) در فركانس 2GHz مي باشد و دومين فركانس كاري 14/1GHz مي باشد و اندازه اين كار   مي باشد لازم به ذكر است كه حذف هارمونيك و تقسيم كننده بسيار مهم است كه در اين تقسيم كننده 5 هارمونيك حذف شده است.اين تقسيم كننده بر روي برد RT-5880 ساخته و اندازه گيري شده است جواب ساخت و شبيه سازي تطبيق مناسبي دارند.

   Proper design of solar panels and increasing their thermal performance is one of the most important issues of the day. In this dissertation, using Ansys Fluent 19.2 software, a three-dimensional solar chimney power plant for Kermanshah weather conditions and the effect of collector geometric dimensions such as collector height and radius, solar radiation and ambient temperature on mass flow rate, air pressure temperature In the chimney, the output power, thermal efficiency and total efficiency of the power plant as well as the distribution of temperature, pressure and pressure meters were examined. In this study, the collector height was 2 to 8 meters, the collector radius was 100 to 400 meters, the chimney height was 2 meters, the chimney radius was 4 meters and the sunlight was 400 to 1000 watts per square meter. Increased sunlight leads to increased mass flow in the chimney. Increasing the ambient temperature reduces the fluid flow and thus the output power. There is a direct relationship between heat flux and power output of the power plant so that with increasing (decreasing) solar radiation, the output power also increases (decreases) and the thermal efficiency of the solar chimney power plant increases. Increasing the collector radius increases the mass flow rate and thus the power output of the power plant, but increasing the collector height has an inverse relationship with power. As the collector radius or height increases, the total power plant efficiency decreases. Changing the collector radius from 100 meters to 400 meters for a solar flux of 800 watts per square meter increases the output power by 93.6%.    Keywords: Thermal performance, Chimney power plant, Solar energy, Numerical simulation

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.   

  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

Design and Simulation of Microstrip Patch Antenna Array for Wireless Power Transmissio  

مطالعه عددي تاثير عملكرد قوسي در پايداري گودبرداري عميق با سيستم شمع نگهبان

  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.

  Choosing an appropriate Appropriate Retaining Structures is a key for successful completion of the each project. However, such an evaluation involves a complex decision-making process associated with numerous uncertainty factors, imprecise information and judgments. The Analytical Hierarchy Process (AHP) and TOPSIS widely applied to evaluate alternatives related to multiple decision criteria. Nevertheless, the AHP and TOPSIS are incapable of dealing with the inherent subjectivity and ambiguity existing in the mapping of the decision-maker’s judgment to exact numerical values.in this Research , using FAHP and FTOPSIS trying to be an appropriate Appropriate Retaining Structures to be determined. . A case study about the use of these methods is also provided. The results demonstrate the applicability of the methods that can be used for effectively evaluating alternatives