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Abstract- Considering the diverse climates of Iran, the need for architectural design according to climate zones is obvious. Especially in critical thermal conditions this need will be more important and becomes the architect’s most important challenge. Cold climate is one of the important climates which deserve special design. In cold climate, summer is very short and environmental temperature is often below the comfort range, so the most important issue is heating. Since in most of the time we require to increase the temperature up to the comfort range. This article aims to provide solutions for critical climate conditions. So Tabriz with a dry and cold climate was selected and its thermal analysis was done. Through this analysis we find out when there is heating problems and we can design solutions based on these findings. This information will help us to design the selected site conditions.

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In this paper, the effect of high frequency induction welding parameters on the weld quality of welded pipes is studied. In this purpose, process parameters such as current, frequency and edge shape of the weld connection and their effects on the heat distribution are investigated. Experimental investigation is performed by using tensile test, metallography, and micro hardness. This reveals three regions with different grading and various thermo-mechanical treatments. The results show that the grain size decreases about 27 percents as the edge shape is improved. By conducting thermo-magnetic analysis, different current intensities and frequencies are evaluated in the creation of appropriate temperature distribution. The results show that with increasing the current and frequency, the heat-affected zone is expanded and other areas become smaller. The maximum increase of the average temperature in the weld edge, was about 42 percents from 1250 to 1500 amperes per unit increase of the frequency. Micro-hardness test is used to detect micro-structural phases of the weld zone.By comparing the results of the metallography and micro-hardness tests, more uniform weld width was observed with modified edge of the in welded samples. The results represent 18 percents of decrease in the weld width of the modified samples in comparison with samples without edge preparation.

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The purpose of this study was to investigate the possibility of producing a biodegradable film from a new source known as opopanax gum and investigating its physical and mechanical properties. Opopanax gum was purified after two extraction steps and the film was prepared with 4% gum solution and 2.5% glycerol in deionized water. The apparent viscosity of the film solution showed the non-Newtonian shear thickening behavior of the solution. The contraction ratio obtained from opopanax gum film was -0.267 ± 0.095. Water vapor permeability (WVP) of opopanax film was 25.059 ± 0.623. The tensile strength and the elongation percentage at break point obtained for opopanax gum film were 0.376 ± 0.124 MPa and 350.625±108.599, respectively. The opacity percentage of the film was 15.633 ± 0.404, which indicates the desirable clarity of the film. The average contact angle for the film was 34.618 ± 1.992, which can be said that the film is relatively sensitive to humidity. The X-ray diffraction spectrometer pattern showed the semi-crystalline structure of the film. Two endothermic peaks and two exothermic peaks were observed in the DSC thermograms. The thermal analysis of the film also showed 4 mass losses. The structure of the film was investigated using Atomic Force Microscopy. The FTIR test showed that the main part of the film is polysaccharide. The total results from different experiments showed that opopanax gum has the ability to form film. However, opopanax gum is not alone desirable to produce edible film due to its high thickness, high solubility in water, high permeability to water vapor and poor mechanical properties. Therefore, it could be an appropriate option for combining with other films to enhance biodegradability of the films.

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In the present paper, thermal analysis of used spiral bevel gears in main gearbox of helicopter- belong to Iran Aircraft Manufacturing- is investigated. Firstly, with introducing the geometry properties of gears, basic lubrication and thermal analyses are considered based on standards of gear design such as AGMA. Then, in order to create the finite element model, initial and boundary conditions with considering the oil viscosity and calculating the friction coefficient, convection and heat conduction coefficients are determined based on experimental and analytical models in spiral bevel gear. It is noted that, the goal of finite element model is considered to reduce the complex calculation errors and increase the speed of problem solving. Effects of various parameters such as increasing the FLASH temperature and influences of initial temperature on it, contact stresses and heat fluxes, comparison of different mineral oils on the decreasing of temperature and fatigue life are examined. The obtained results of present work show that the FLASH temperature of main gearbox is linear function of initial temperature, so that FLASH temperature increases 56 centigrade in comparison of initial temperature. Also, it is demonstrated that the presence of various mineral oils in this system lead to reduce the solid-solid surface contact and friction coefficient. Moreover, these lubricants cause the cooling in the gearbox and enhancing more temperature, thus the employing these lubricants lead to exceed the system temperature to 90 centigrade.

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In this paper, optimization phase angle of alpha Stirling engine performed step by step method. After studying on the operation of various types of Stirling engines, the effect of the phase angle on the power and efficiency of Alpha Stirling engines was studied. The kinematic modeling of volumetric compression and expansion volumes has been done by ADAMS software. Then, the linearization of the thermodynamic equations was carried out on the basis of analysis of the isothermal and five-volume adiabatic stirling cycles to obtain the initial solution of its effective parameters on the power and efficiency. To optimize the phase angle between compression and expansion pistons, stepwise numerical solution of the stirling cycle was performed. Comparison of numerical solution with experimental data indicates an error rate of less than 5.3%. The simulation results show the optimum phase angle of 103 °. At this optimal angle, the results indicate an increase of 4.8% of the output power rather than the output power at a 90 ° pre-aligned angle. Simulation results indicate an improvement of 1.2% of the Alpha Stirling engine efficiency by adjusting this phase priority angle to the efficiency at 90 °.

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Since transformers are one of the most important and most used equipment in power network, investigating the factors which affect the loss of these equipments is of particular importance. Nowadays Amorphous metal core transformers have a significant place in today power market, since they exhibit 60-70% lower no-load losses compared to the Silicon crystalline steel core transformers. In order to enhance the design and cost and also to shorten the time to produce Amorphous metal core transformers, numerical analysis of the no-load as well as load conditions are of paramount importance and hence should be considered. On the other hand, temperature is one of the important and effective factors in transformer life, because increasing the transformer temperature leads to reduction of its rated life. In this paper, a 100 KVA unit transformer has been simulated by coupling ANSYS Maxwell and ANSYS FLUENT softwares and no-load and load losses are investigated. The results show that amorphous core transformer compared to Silicon Crystalline Steel core transformer reduce no-load losses about 65 percent. Furthermore, thermal analysis shows amorphous core transformer has lower temperature compared to the Silicon core transformer in no-load conditions.

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In this study, 19 samples of biodegradable films using modified starch (0-2 g), albumin (2-0 g), nanoparticles of magnesium oxide (0-5%), were prepared and physicochemical properties including colorimetric, transparency, mechanical, calorimetry and morphological properties were investigated. Addition of magnesium nanoparticles to modified starch-based nanocomposite films and albumin decreased the transparency and increased the opacity of the films and increased the a, b and YI index, indicating an increase in yellow color in films containing high concentrations of MgO nanoparticles and an increase in E film. The addition of MgO nanoparticles to them also improved the strength and mechanical properties of the films (tensile strength and strain to breaking point). Films containing magnesium oxide nanoparticles showed an increase in glass transition temperature, a melting temperature and a decrease in crystallization temperature; Which confirms the positive effect of MgO nanoparticles on increasing the thermal stability of nanobiocomposite films. SEM images of the produced films showed a heterogeneous level in films containing magnesium oxide nanoparticles compared to films without nanoparticles.

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This paper investigates the behavior of a steel moment frame system with long spans subjected to compartment fires and progressive collapse scenarios due to girder drop and column removal. In this study, initially, a typical 15 – story building with moment frame system with long spans and story height 3.2 (m) was designed using relevant chapters of national building code of Iran for conventional gravity and lateral loads. In order to perform thermal analyses, the most critical frame of this structure is modelled in finite element software OpenSees. Then the nonlinear behavior of the frame is studied at elevated temperatures under different fire scenarios and progressive collapse Scenarios due to girder drop and column removal. In this analyses, the structure is subjected to both gravity and thermal loading simultaneously. Also for performing thermal analyses, nonlinear analyses and standard fire curve (ISO 834) are used.
Results of this study indicate that beams do not deform significantly until approximately 400°C, but after that, vertical displacements of beams increase significantly due to degrading mechanical properties of steel. So beams deform and collapse at about 500°C to 600°C. Also heating the beams of structure, initially causes the axial force in the beams due to thermal expansion restraint. So Demand to Capacity Ratios of beams increase from early stages of fire and the most increase in DCR_nom occurs at about 350°C to 400°C. Also by one story girder drop, columns survive to 500°C. But at higher temperatures (about 600°C to 800°C), these heated columns lose their strength and buckle. In column removal scenarios in first and 7^th story, where beams have lost their strength under effect of gravity loads and at about 400°C respectively, more damage is observed compared to girder drop scenarios.
 

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Given the growing interest in the production of new and low cost bioemulsifiers, the rice and wheat bran and straw were investigated in this study for the production of bioemulsifier by Lactobacillus plantarum subsp. plantarum PTCC 1896 (probiotic). The strain produced bioemulsifier only in the rice bran hydrolysate medium. The bioemulsifier amount reached around 0.7 g L^-1 for 72 hours of fermentation. The new biomolecule was extracted, purified, and its structural and thermal properties were evaluated. The functional groups and the structure of the molecule were revealed by GPC, FT-IR, ¹HNMR and ¹³CNMR techniques. The bioemulsifier was a water soluble extracellular high molecular weight (>10⁷ Da) α-glucan (81.74%) bound with protein (18.18%). Thermal behavior was studied using DSC and TG analysis. Thermal analysis showed the bioemulsifier broke down above 211.74°C, and the melting point was 182.0°C with the enthalpy value of 101.7 J g^-1. These results might provide incentives for the industrial production of the biodegradable and safe bioemulsifier introduced in this study, which seems to offer potential applications in the food and medical industries.

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Inconel 718 is used in a wide range of industries such as oil and gas, nuclear, aviation, and etc. due to its excellent mechanical properties. The use of additive manufacturing (AM) to manufacture parts is increasing rapidly Due to the dimensional limitations in the manufacturing of parts using the additive manufacturing methods, these parts must be connected to other parts in different applications with the help of conventional methods such as welding. In this research, the thermal analysis of plasma welding of an Inconel 718 sheet made by SLM method using ABAQUS software is discussed. Input heat with Gaussian distribution was entered into the model by DFLUX subprogram with FORTRAN program language. In order to validate the thermal model, the temperature was measured during the welding process using a thermocouple. A relatively good match is observed between the numerical and experimental thermal analysis results. The microstructure of the welded samples was examined with an optical microscope and the microstructure of base metal, fusion zone, and heat affected zone were investigated. The dendritic structure in the welding area and the occurrence of recrystallization in the heat-affected area was evident. The tensile test results showed that the sample without welding has a higher yield and ductility.