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Steel plates are widely used in various industries, especially in civil engineering. Low cost in implementation and reduction of seismic mass are the advantage of steel shear wall system compared to other structural systems. The goal of a good design is that along with following the existing guidelines and achieving the desired seismic resistance of the structure, the structure is affordable in terms of weight and cost. Considering that according to the design, it is not possible to achieve the optimal use of the structure's capacity by force control method, the theory of uniform deformations was proposed with the assumption of a constant performance level. The subject of design based on performance increase the safety of the structure against earthquake force and design with optimal seismic performance during the useful life of the structure in seismic areas. Also, compared to the design method based on force control, it can lead to a lighter and economical design.
One of the significant ways to reduce the weight and stiffness of shear walls and boundary elements connected to them is to limit the connection of filler plates to boundary elements. In this method, limiting the length of the connection reduces the force on the beams and columns, and as a result, smaller sections can be used.
In this research, in order to achieve the optimal performance level, two concrete frames with steel shear wall resistant system are subjected to nonlinear analysis. Then, the initial evaluation of the behavior and the correctness of the used method are checked. After that, the effective factors in achieving uniform stress in the height of the structure will be investigated. For this purpose, by using the effect of the thickness parameter and the appropriate pattern of connection of the shear steel plate to the surrounding elements, the way of changing the performance and behavior of the structure will be investigated. For this purpose, 3- and 4-story concrete frames with steel shear wall systems were modeled using ABAQUS^TM finite element software. The steel used in the steel shear wall system is ST37. First, the connection of steel shear plates to floor beams was considered and then the influence of the partial connection pattern on the seismic performance of the steel shear wall system was investigated. The modeled frames were subjected to dynamic analysis, linear and nonlinear buckling analysis, and cyclic analysis. Based on the obtained results, the property of energy dissipation in the frame with a steel shear wall system with partial connection has increased significantly. Changing the partial connection pattern led to changing the maximum in-plan relative displacement. Also, the surface of the stress distribution shows that in the partial connection, the stress concentration mainly occurred in the place of the steel shear plate connections. In addition, according to the results of cyclic analysis, considering the partial connection of the steel shear wall has led to a decrease in the average energy absorbed in the structure and an increase in its ductility. Also, changing the connection pattern has affected the average amount of absorbed energy in different loading cycles.

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Marine transportation is the most conventional method for transportation of natural gas, mostly liquid form; namely, Liquefied Natural Gas (LNG) to international far market. Hereon provide safe transportation of natural gas is very important. In the event of exterior material contact to LNG, swift boiling and exploding anticipated. The paper, investigates thermo physical water contact (0oC as a fluid with higher temperature) with liquid methane (cause the similarity of thermo physical properties to LNG) at low temperature (-162oC). The intensity of heat transfer between water particle and liquefied methane resulted to swift pressure increase in vapor film. It causes the generation and swift growth of methane vapor film which has been resulted from abrupt evaporation and results to liquid methane explosion. In this situation, the intense vapor explosion phenomena, endangers the safety of system. Mathematical model of these phenomena has been developed by assuming saturation condition on interface phase. Then, the effects of different thermo physical parameter changes on vapor film growth have been investigated. Based on the results, in some cases, the vapor pressure pulse created in the film has been more than 3 times the initial pressure, which can endanger the safety of system.

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In this paper, dynamic analysis of simply-supported composite sandwich beam under a moving mass including rotary inertia and transverse shear deformation are investigated. Governing equations are gained using Hamilton's principal. Modal superposition method used to deriving ordinary differential equation of motion in matrix form. Fourth order Runge-Kutta method applied to solving the ODE with time varying coefficients. Parametric studies such as effects of stacking, aspect ratio, core thickness and stiffness, mass and speed of moving load on the midpoint deflection, dynamic magnification factor and critical speed have been studied. The obtained results show that core thickness and stiffness have considerable effects on critical speed. Inertia of moving mass has distinct effects on dynamic response of beam depend on load velocity.

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In recent years, development of effective devices for seismic energy dissipation in structures has become more important to keep response of structure in elastic range. Dampers are used in structures to reduce response and effect of seismic forces. Also, using secondary mass technology can help seismic energy dissipation. Among these systems one can mention tuned mass damper and tuned liquid column damper, working base on secondary inertia in structures. In this paper, hybrid system of tuned mass & liquid column dampers in series was considered with mass ratios 0.035-0.005, 0.03-0.01 and 0.02-0.02. Time history analysis using the Northridge, Tabas and Loma Prieta earthquakes for 20 story structures were modeled in Simulink Matlab software considering shearing structure and damper modeling in every blocks separately. Effect of damper to structure is determined as forces applying on corresponding story. Performance indices using software outputs such as root mean square and Maximum of displacement and acceleration of stories were calculated. Performance of single and hybrid systems has been compared due to different earthquakes. Also effect of hybrid systems in series was studied by increasing head loss coefficient. Results show that performance of hybrid systems is dependent on earthquake characteristics that improves with increasing secondary mass ratio. For example under the Northridge earthquake, hybrid system in series tuned mass & liquid column damper with mass ratios 0.035-0.005, 0.03-0.01 and 0.02-0.02 decrease root mean square of displacement of stories 45, 27 and 2 percent respectively and also by selecting optimum frequency ratio based on responses of structure. For example maximum acceleration of hybrid system of tuned mass & liquid column damper in series with mass ratio 0.035-0.005 is optimum frequency ratio in 2.9 and also by selecting this frequency ratio decrease maximum acceleration of up and down stories in 20 story structure. By comparing effects of hybrid system Tuned Mass & Liquid Column Damper in series with different mass ratios on two structures with periods of 1.5 and 2.44 second are considering where by increasing stiffness of structure, performance of hybrid system was improved leading to decrease of acceleration responses and reduction of displacement responses. For example, J1 in 20 story structure with period 1.5 second is 0.71 whereas in other structure is 0.79 that show hybrid system has better performance in structure with period 1.5 second. Hybrid system in series damper with mass ratio 0.035-0.005 have best performance to reduce displacement stories of 20 story structure with period 1.5 second as J3=0.56 means decrease 44%. Also in other structure, hybrid system with mass ratio 0.035-0.005 has best performance to reduce displacement at top floor with J4=0.56. Also performance of hybrid system to reduce maximum displacement of stories was improved by increasing head loss coefficient in tuned liquid column damper

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Plasma assisted machining (PAM) is a method to improve machinability of hard turning. The process of plasma assisted machining for turning applications utilizes a high-temperature plasma arc to provide a controlled source of localized heat, which softens only that small portion of the work material removed by the cutting tool. The goal of this study is to present a methodology for determination cutting force during plasma enhanced turning of hardened steel AISI 4140. In this regard, a finite differential model was made to estimate the uncut chip temperature under different plasma currents, cutting speeds and feeds during PAM. A mechanistic model developed to estimate cutting force under different PAM conditions by considering shear stresses in the primary, secondary shear zones and force on the tool edge. The proposed model was calibrated with experimental hard turning data, and further validated over practical PAM conditions. Mean errors of predicted values and experimental data is lower than 10 percent. It is shown that PAM can decrease main cutting force in comparison to convectional to 40 percent in turning of hardened steel at high levels of uncut chip temperature due to softening the material.

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Study of the seismic response of a site, requires the accurate estimation of the Shear modulus (G) and damping ratio (D) of under ground layers in that area. According to the unsaturated condition of an extensive part of the earth surface, it is necessary to perform unsaturated tests to determine dynamic or cyclic parameters of these regions. On the other hand, because of inherent complications of unsaturated testing equipment, this field of experience has had less attention. But in recent years by development of advanced experimental equipment some studies have been developed based on the dynamic parameters of unsaturated soils.
A large amount of the researches related to cyclic and dynamic parameters of unsaturated soils are the studies about determination of these parameters in very small strain levels (initial shear modulus and initial damping ratio) and the effects of some factors such as suction, mean net stress, suction history, anisotropy and pre-consolidation on them, using bender element technique and resonant column torsional shear apparatus. But there is less attention in experimental studies in the strain ranges of medium to large and determination of the parameters G (shear modulus) and D (damping ratio), and also the normalized shear modulus reduction and damping ratio curves for unsaturated soils.
In this research, it is tried to determine the shear modulus and damping ratio parameters in medium to large strain levels using suction controlled cyclic triaxial apparatus and study the effect of changes in matric suction and mean net stress on these parameters in a kind of unsaturated clay with plasticity index of 24 under high loading rates. In this regard, some tests are performed on different paths including two suction levels (zero and 300 KPa), in mean net stress level of 200 KPa and three deviatoric cyclic stress ranges (18, 42 and 81 KPa) up to 60 loading cycles. Also a comparison is done between the results obtained from the current research and the results of another research which was performed in the same paths on a fine grained soil with plasticity index of 12 using the same equipment.
The results of this research show that increase in suction level results in raising shear modulus and decreasing in damping ratio values. In addition in the same strain level, by increasing the number of loading cycles, the shear modulus values are increased and the damping ratio values are decreased.
Considering the results of current research (unsaturated cyclic tests on unsaturated normally consolidated fat clay with plasticity index of 24) with the results of another experimental research in the field of unsaturated cyclic tests on unsaturated normally consolidated lean clay with plasticity index of 12, in the same sample preparation process and the same stress paths, is indicated that the changes of the shear modulus values of the high plasticity samples are in the lower level related to the values of the samples with plasticity index of 12. In the other word, the increase in plasticity index decreases the stiffness of the samples considerably. But the change in damping ratio values is shown relatively the same trend in both groups of the samples.

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The velocity of shear wave, which is utilized in evaluation of the stiffness and strength of subsurface layers, the geotechnical site effects of earthquakes, and determination of the profile of subsurface layers is one of the most prominent and essential parameters in geotechnical studies. The profile of shear wave velocity of soil layer is usually discerned in the site by means of prevalent direct seismic and geophysical methods such as reflection, refraction like SASW and MASW, and borehole ways or indirectly, by geotechnical methods such as conducting CPT or SPT sounding and employing experimental relations among Vs and CPT or SPT quantities. As far as these methods need to dig boreholes, it is obvious that deploying borehole geophysical methods or geotechnical ones to certify the profile of shear wave velocity is expensive and time-consuming. As an economical and practical alternative, the measurements of microtremors which can be easily implemented on the ground surface at a single station. Firstly, the method registers ambient vibrations; then, the spectral proportion of the average of horizontal components to vertical component of microtremors (H/V) are determined. At the end, shear wave velocity profile of the site are discerned by inversion of the H/V spectrum in a reversal algorithm. The analyses are easily performed by means Dinver program of useful package of Geopsy software. In this study, single station microtremor measurements are done at six points along Kermanshah Urban Railroad project. In order to determine shear wave velocity profile from inversion of H/V spectrum, four shear wave models with 3,5,7,and 10 layers are initially suggested for all mentioned six points. All initial models were similar in parameters like thickness of layers and range of shear wave velocity in each layer, so that final conclusions and interpretations can be made for future studies. The best of achieved shear wave velocity profiles in terms of minimum misfit error of inversion of horizontal to vertical spectral peak are compared with the result of field Vs measurements that were performed by down-hole experiments. The most outstanding point is that, the procedure is utilized to find shear wave velocity profile without considering the results of down-hole tests for thickness and velocity limits. The comparison showed that there are significant compatibility between shear wave velocity profiles achieved by inversion method and the results of field down-hole tests. Generally, this compatibility increases with increasing the number of layers from three to ten layers of initial models. Furthermore, the depth of exploration grows with increasing the number of layers as well as the accuracy of profiles, so the initial model with 10 layers has more consistency with the results of borehole experiments of all six points in relation to other models. However, it is obvious that the time for analyzing initial model with 10 layers is more than other ones and a tradeoff between accuracy and time of analyses must determine the acceptable results. In conclusion, inversion of H/V spectrum method shows the ability to appropriately estimate shear wave velocity profile even in deeper sediments in relation to down-hole tests.

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Seismic wave propagation in surficial stratified soil and deep rock is studied in many engineering fields like Geotechnical earthquake engineering, Geophysics and seismology. Seismic waves might be generated by a significant seismic event, volume collapse in earth’s mantle, chemical or nuclear explosions and surface impact sources. Although the seismic waves’ path in soil layers may be shorter than their path in bedrock, they are influenced significantly by the mechanical properties of surficial soil layers. Soil layers may be saturated or not fully-saturated by a single fluid, which is known as unsaturated soil. Seismic waves generated at the source are known to be body waves of two categories (a) compressional wave (P-wave), (b) shear wave (S-wave).In spite of the abundance and deepness of theoretical analyses, experimental results on measuring the compressional waves in unsaturated soils and rocks are inadequate and mainly have focused on the relation between first compressional wave velocity and degree of saturation instead of suction. Furthermore, the experiments focus on the specimens of sandy soils and rocks with a series of repeated experiments in various degree of saturation conditions. This paper presents the results of three series of ultrasonic tests carried out on fine grained soils.The soils chosen for experimental study are three commercial kaolin named ZK1, ZK2, and ZK3, from Zenoz mine in northwest Iran. These materials have plasticity index (IP) of 9%, 15%, and 19%, and classified as lean clay (CL), silt (ML), and elastic silt (MH) respectively according to Unified Soil Classification System. 15 specimens were compacted at different initial water contents and void ratios and subsequently allowed to dry gradually until air-dry. cylindrical samples, 50 mm in diameter and 100 mm high, were prepared in a mold by compacting a soil – distilled water mixture at proctor optimum dry density and another four points of standard proctor compaction curves; two at 0.5 kN/m3 less than optimum dry density in both dry and wet side of optimum water content point and two at 1 kN/m3 less than optimum dry density in dry and wet side of optimum water content point. All samples were compacted in seven layers using the under-compaction technique to ensure specimen homogeneity along the height. Measurements of compressional wave velocity (Vp) (using ultrasonic) and matrix suction (using the filter paper technique), together with water content, were made at various stages during the drying process (4 times for each specimens; at the time of making the sample and after 4, 8, and 16 hours). The results of the tests suggest that, as a soil dries, its compressional wave velocity increases with increasing in suction. The results imply that in prediction of compressional wave velocity the effectiveness of void ratio must be considered as well as the suction effects. Both compressional wave velocity (Vp) and the corresponding suction (s), have been shown to vary in consist and predictable manner as a function of the initial void ratio at compaction state (ecomp), the suction and the soil’s plasticity index (PI). Thus, an empirical expression was developed which permits estimation of the value of compressional wave velocity, Vp of compacted fine grained soils subject to drying at the suction and material properties expected in prototype conditions.

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Extensive consumption of confectionery cream and production of products with reduced fat, strengthens the need to replace stabilizing and emulsifying compounds in it. Therefore, in this study, the effect of adding modified basil seed gum (BSG) and rice bran protein isolate (RBP) was investigated. First, the amount of insoluble aggregates and turbidity of basil seed gum solutions and rice bran protein at pH 3, 5 and 7 were investigated. Then, in confectionery creams with 25, 30 and 35% fat content in concentrations of 0.5 and 1% were added and the characteristics of volume increase, foam stability and firmness of confectionery cream were studied as important physicochemical characteristics of cream. The results showed that the highest amount of insoluble accumulations was obtained in basil seed gum at pHs 3 and 5 and the lowest in rice bran protein isolate at pH 7. In contrast, the highest turbidity was observed for RBP at pH 7 and the lowest turbidity in BSG at the same pH. The highest increase in volume and stability of confectionery cream foam was obtained in RBP in 30% fat cream, followed by RBP with 25% fat cream and whey protein containing 35% fat cream. In contrast, the lowest increase in volume was observed in BSG samples.I n contrast, confectionery cream with the highest percentage of fat and the highest amount of basil seed gum had the highest texture firmness. Therefore, according to the results, it is clear that pastry cream with the highest percentage of fat and the least amount of protein can lead to maximum foam stability. Overall, the results showed that RBP has a good ability to be used in confectionery cream formula, although BSG is not able to be used in cream due to lack of protein.

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Fine grain materials exhibit excellent mechanical properties and are widely used in various industries. One way to produce fine grain bar is by using the severe plastic deformation techniques. Cyclic extrusion and expansion of the sample is used as one of the methods of severe plastic deformation for production of fine-grained bars. As the length of piece increases, the friction force increases, so that the required force for shaping operation is increased to such an extent that the process cannot be performed. For solving this problem, the "Cyclic Extrusion and Expansion under Hydrostatic Pressure" is proposed as a new method of severe plastic deformation for production of long-length fine-grained bars. In this method, the forming operation was done by using a pressure oil, so the hydrostatic compressive stresses are applying to the material and improve the mechanical properties. Also, the results of simulation of finite elements of this method show the effect of friction coefficient on the forming force and independence of the forming force from the bar length due to the hydrostatic process. Therefor the process is capable of producing rods of long length and fine structure. Results of pure copper rebar underwent this process showing that the yield strength and final strength increased by 200% and 33%, respectively. Also, the sample hardness increased substantially by 120%, and the distribution of relatively homogeneous hardness in rebar diameter was obtained. The microstructure results showed a fine-grain after the process, with the grain size reduced to 8μm in center and 5μm in outer diameter.

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In the present study, the feasibility of ensuring uniform deformations in the lateral bearing system of thin steel shear walls has been investigated. For this purpose, using ABAQUSTM finite element software, a 3-story concrete frame was modeled and analyzed by the nonlinear time history analysis method. Due to the lower weight, speed of execution and consequently the reduction of construction costs in steel shear walls compared to reinforced concrete shear walls, they have been significantly developed. In important buildings in North America and Japan, this type of lateral bearing system has shown very good behavior against strongly earthquakes. Also, due to the good performance of steel shear wall systems, the use of steel shear wall in seismic countries during earthquakes in North Ridge, USA, Kobe and Japan has greatly increased. The system of steel shear walls is similar in performance to plate girder. In steel shear walls, the columns act like flanges, the filler steel plate acts as the web and beam similar to the stiffeners in the plate girder system. In general, the performance of steel shear walls is based on the creation of a diagonal tensile field in the steel plate that occurs after buckling. In 2003, the Canadian Steel Structures FEMA 450 proposed guidelines for the design of steel shear walls. In 2005, the design requirements for steel shear walls with special details were added to the steel structures section of the AISC Regulation. According to ASSHTO 2018 regulations, steel plates are divided into three behavioral ranges slender, moderate, and stocky according to their thickness. In 2021, during research, a new method for evaluating the behavior of steel shear walls with the relationship of part of the plate height to the vertical boundary elements was reviewed. In this type of connection, the middle of the filler plate was not connected to the vertical boundary elements. In this type of connection, reducing the connection length between the filler plate and the vertical elements leads to a reduction in stiffness and bending on the vertical boundary elements. In this paper, three different thicknesses were selected in the behavioral range of slender plates and how to connect them to the surrounding elements was defined in whole and in partial. In this evaluation, the effect of changing the connection length of the steel plate for the range of slender plates is investigated. The connection of steel shear walls to the surrounding members (beams and columns) is based on the percentage of the shear plate and the connection length ratio of steel plates are examined on the maximum relative in-plane displacement (drift) and the displacement of all stories. Uniform distribution of live and dead loads for the roof floor 1 and 5.3 (KNm2) respectively and for the other floors equal to 2.5 and 5.5 (KNm2) respectively is assumed. The behavior of the frame in the first stage is evaluated by the record of the Kobe earthquake. The results showed that in general, reducing the length of the plate connection leads to an increase in the maximum relative in-plane displacement (drift) of the stories and it is possible to control the ductility of the structure. 0. 6  is the critical area for a sender plate 5 mm. Because due to the early buckling and the occurrence of resistance after buckling, the maximum relative in-plane displacement (drift) has decreased. Also, 0.6 and CLR≥0 / 75 introduced as critical areas for 2 mm and 8 mm plates, respectively. In slender plates with very small thicknesses, the shear strength is very low and can be ignored, and the plate enters the post-buckling resistance immediately after loading. For this reason, the results of these plates determine the behavior of the structure. By reducing the thickness, the non-uniformity in the maximum relative in-plane displacement (drift) of the stories was seen, which was significantly improved by using suitable partial connections of the shear steel plate to the surrounding elements.

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The present study seeks to examine the functions of transformational leadership in knowledge-based organizations using the grounded theory. Research method is based on the qualitative method of grounded theory. Depth interviews were conducted with 16 experts of the Technical and Vocational University of Tehran selected through snowball sampling. After open, selective, and axial coding of collected data, 160 primary concepts, 29 subcategories and 5 main categories were extracted. The final outcome of this study is the design of a 5-dimensional model whose dimensions are categorized into four bases of strategy, outcomes, interventional conditions, ground-making conditions and causal conditions. The findings of this study indicate that the main function of transformational leaders is a capacity for organizational adaptability. In fact, transformational leaders at Tehran’s Technical and Vocational University resort to adaptability strategy to affect the performance of followers and manage organizational change. It is, therefore, suggested that transformational leaders strengthen corporate social capital by improving horizontal interactions between colleagues, building trust, engaging and collaborating with employees in decision-making, reinforcing the spirit of taking criticism among themselves and colleagues; empower the human labor by their involvement in important organizational decisions and ultimately encourage employees to adapt to changes through empowerment techniques.
 

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Steel bracing is known as one of the most effective systems resistant to lateral loads, and its use has been the subject of numerous studies to improve the lateral deformation tolerance of existing reinforced concrete frames. In this study, the seismic performance of steel bracing in the concentric plane in order to strengthen the existing reinforced concrete structures has been numerically investigated. A scaled reinforced concrete frame was modeled by finite element method by simple cross bracing. In the retrofitting of damaged reinforced concrete structures, attention should be paid to the continuity of service of the structure in structures of high importance. The important point in buildings of special importance such as hospitals and government buildings is that in such buildings the maintenance of the structure must be maintained at all hours. In addition, the implementation of in-plane bracing causes the destruction of intermediate frame components and can reduce the effective role of intermediate frame components in the seismic load of reinforced concrete frames. The interaction between the frame and the frame in seismic loading is an important issue that has been extensively focused on by various researches. Another important point is to pay attention to architectural issues and match the retrofit method with the aesthetic aspects of the structure. If there is an opening in the damaged frame, using the internal reinforcement method may cause problems in the opening space in the desired frame.
According to the mentioned points, in order to continue the service of the structure during the retrofit operation and to reduce the destruction operation in the intermediate frame components, the reinforcement member can be externally connected to the damaged frame. Therefore, in this study, in order to achieve the mentioned goals, the implementation of steel bracing outside the plane was also investigated using the numerical method and its Possibility was verified. The studied sample was subjected to lateral load by displacement control method by ABAQUS software and analyzed by quasi-static method. This enables a better understanding of the performance of frames strengthened with in-plane and out-of-plane steel braces and the evaluation of the proposed method. In this study, the models were examined in terms of deformation and cracking characteristics, hysteresis, lateral stiffness reduction and energy absorption capability.The results of this study showed that after strengthening with braces, there was no local rupture due to the application of lateral load in the place of the plastic joints of the frames. As a result of the application of lateral load, the normal moment frame specimen showed a more fragile hysteretic behavior. The maximum resistance value of the reinforced concrete frame in a certain displacement after strengthening increased to 2.5 times of its original sample and resulted in less stress concentration in the boundary elements compared to in-plane bracing. The amount of hardness created in the sample increased to 1.35 times of the original sample and the amount of energy absorption increased to 2.25 times of the original sample. The results obtained in hysteresis, stiffness reduction and energy absorption sections indicate the effective performance of the proposed method in strengthening damaged reinforced concrete structures.