Humans use lateral bracing systems in structures to deal with the lateral force that is applied to structures through earthquakes. In metal structures, braces are used to deal with this force, which behave in tension and compression. Brace systems are classified into different types, such as divergent and convergent brace frames and knee element braces. Convergent brace systems are more rigid than reduced section frames and bending frames, but less ductile. In order to increase the ductility of frames, the divergent brace system was invented by Mr. Popov in 1987. In this system, a member that was located as a connecting beam along the main beam element of the frame was responsible for energy dissipation. After the earthquake, if the beam element was continuous, the entire element would have to be replaced. However, if the connecting beam was guided and flanged to the main beam, it would be repairable and replaceable. In this case, the roof of the floor would have to be destroyed. After this, researchers searched for a system through research and laboratory studies. In 1986, a system called the Knee Brace Frame (KBF) was developed by Mr. Ochoa, which eliminated the shortcomings of previous systems. This system has reduced the cross-section and the bending frame has more stiffness and energy dissipation compared to divergent systems. In this study, the hysteresis curve of the knee brace frame (KBF) was first extracted through finite element software (ABACUS) and compared with the experimental model for verification. Then, by doubling the column length and considering it for the beam length, this rectangular sample was examined and analyzed in three models in ABACUS. In the KBF1 model, the beam length is 5.6 meters and the column height is 2.8 meters. The knee brace length is 0.55 meters. The diagonal brace X is passed through the beam and column X at the connection node, and the diagonal brace is perpendicular to the knee brace, but the knee brace length is not divided into two equal parts. In the KBF model, the beam length 5.6 meters and the column height is 2.85 meters, the length of the knee brace is 0.55 meters. And the diagonal brace is again perpendicular to the knee brace, but the X of the brace does not pass through the X of the beam and column at the connection node and divides the knee brace into two equal parts. Continuing in the KBF3 model, where the beam length is 5.6 meters and the column height is 2.85 meters, the length of the knee brace is 0.55 meters, the X of the diagonal brace passes through the X of the beam and column at the connection node and the diagonal brace is not perpendicular to the knee element, but the length of the knee brace is divided into two equal parts. Continuing in the form of a square model, which considers the height of the beam and column as 2.8 meters and the length of the knee brace as 0.22 meters, and the X of the diagonal brace passes through the X of the beam and column connection node and the diagonal brace is perpendicular to the knee element and divides the length of the knee element into two equal parts, but makes the length of the knee element much shorter, as much as twice the length. The knee element length in KBF1 mode is considered to be 22 cm, which means that the square model shows better stiffness, energy dissipation, and lateral load-bearing capacity than the other models. In this study, the behavior of steel materials and welds is controlled by failure criteria in different parts of the connection and the failure mechanism.

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

   Abstract 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.

   This research investigates the transient liquid phase bonding process assisted by electric current for joining thin sections. The simulation of this process was conducted using COMSOL software in two systems: copper-carbon steel-copper and copper-tin-copper, with varying layer thicknesses. The primary objective was to analyze temperature distribution and atomic diffusion during the bonding process. The results showed that in the copper-carbon steel-copper system, the temperature at the center of the piece reached approximately 1590°C, sufficient to melt the interlayer. It was also observed that increasing the base layer thickness from 1 mm to 5 mm resulted in a higher final bonding temperature. Atomic diffusion analysis revealed that the maximum diffusion depth occurred with a base layer thickness of 1 mm and an interlayer thickness of 0.02 mm, reaching a depth of 0.252 mm. In the copper-tin-copper system, the center temperature of the sample reached approximately 766°C, adequate for melting the tin layer. Modeling indicated that in both systems, the sample remained at the final bonding temperature for over 95% of the bonding time, highlighting a unique advantage of this method. The results were validated by comparing them with experimental data available in the literature, showing good agreement. This research's findings can contribute to the optimal design of transient liquid phase resistance bonding processes for industrial applications, particularly in microelectronics.

  Humans use lateral restraint systems in structures to deal with the lateral force that enters the structures through earthquakes, and braces are used in metal structures to deal with this force, which behave in a tensile and compressive manner. Braces are classified in different types, such as divergent and convergent bracing frames and knee element bracing systems. Convergent bracing systems have a reduced cross-section compared to frames and the bending frame is more rigid but less malleable, in order to increase malleability. Frames In 1987, the diverging brace system was invented by Mr. Popov. In this system, the member that was located as a connecting beam along the length of the main beam element of the frame was responsible for energy consumption. After the earthquake, if the beam element was continuous, the entire element should be replaced and replaced. If the connecting beam was guided and installed in the main beam with a flange connection, it could be repaired and replaced, otherwise the roof of the floor would have to be destroyed. In 1986, a system by Mr. Ochoa called the knee brace frame(KBF)which fixed the shortcomings of the previous systems. Compared to the divergent and segmental systems, this system has reduced stiffness and more energy consumption of the bending frame. In this study, first, through the finite element software (Abaqus), the hysteresis curve of the bending frame was calculated. With the knee brace, we extracted and compared it with a laboratory model for validation. In the following, we checked the same bending frame by removing the knee element, and then by increasing the length of the knee element and changing the knee connection from bending to joint, which in the first case, considering The bending frame means the connection of the beam to the welded support column and the support bracket (welded) and the increase in the length of the knee element, the stiffness and the energy consumption and the lateral load are increased. In the following, all these models are changed from the connection of the beam to the support column in the previous state to a joint (welded joint). We have changed and considered the bracing to be of the welded type, which reduces the hardness, energy consumption, and side load a little, which in the following is in a similar model, such as the verification sample of the connection of the beam to the hinged column (welded) and considering the brace to be of the hinged type (pin) Considering that the hardness and energy consumption have decreased, but the resistance limit has slightly decreased with s Shear and bending mode in the link beam is dealt with in EBF frames, and if there is an architectural need and creating an opening in the frames, KBMF frame can be used with the failure of the link beam shear mode because it has Translated from Persian to English - www.onlinedoctranslator.com better stiffness and energy consumption. In this study, the behavior of steel and welding materials has been controlled by failure criteria in different parts of the connection and rupture mechanism

  يكي از سيستم هاي

   Dental implants are subject to complex mechanical and biological conditions. On the one hand, it is under cyclic pressure and corrosive environment, and on the other hand, chemical reactions occur on the surface of the implant with the biological environment. Therefore, not only surface conditions and topography, but also strength, fatigue resistance and biocompatibility will be important in the implant placement process. Currently, some grades of titanium such as grade 2, 4 and 5, as well as some alloys such as Ti-6Al-4V alloy and Ti-Ni duplex alloy are used by different manufacturers to make dental implants. Considerable information on the properties of these materials can be found in scientific sources, however, it is difficult to compare these materials in order to select appropriate materials for biological applications. Because the different working conditions for using these materials, as well as the history of the operations performed on these materials, make it difficult to compare them. In this research, the surface properties, corrosion, and biocompatibility of some titanium alloys will be studied after acid washing and surface modification under the same conditions.   Keywords: implant - fatigue - titanium zirconium alloy.

connections experienced brittle failure. Therefore, in order to prevent the brittlefailure of connections and to protect the main structural members from damagedue to seismic forces, slotted steel dampers were used at the beam-to-columnjunction. The analyzes carried out in the finite element software showed that in thecase of using slotted dampers with a conventional slot shape, the stressconcentration is only created at the end points of the strips and the middle parts donot play a role in energy consumption. In order to solve this problem, in this study,semi-elliptical gaps were used in the slotted damper. Then, the influence of thewidth of the damper strips on the seismic performance of beam-to-columnconnections was investigated. The results of the analysis showed that the use ofthe proposed slotted damper improves the seismic performance of the connection.Also, by reducing the distance between the slits, the participation rate of the middleparts of the slitted damper strips in energy absorption increases. In the next step,the effect of the distribution of the height of the slits on the behavior of the slotteddamper in beam-to-column connections was investigated. The results ofexamination of the samples in the finite element software showed that thedistribution of the height of the slits in the slotted damper with the shape of a halfelliptical slit with a slope of 2 degrees in such a way that the lowest slit height isin the corner and the highest slit height is in the middle, has the highest energyabsorption and ultimate resistance.Key words: earthquake, slit damper, semi-elliptical slot, strip width, slit heightdistribution   

Developing the scope of application of new material depends on understanding the behavior of these in different environments and also gaining knowledge on the effect of various factors such as heat treatment parameters on their properties.   With regard to this issue we focused on the investigation the effect of partial austenitizing duration on creating a matrix with a dual structure of ferrite-ausferrite, corrosion resistance, bending strength, time to failure in crosive media under applied bending loads and stress corrosion threshold stress of a carbidic austempered ductile iron (CADI) which has been known as new family of ADI. In this regard, cast parts from a non-alloy carbidc cast iron were first subjected to ferritizing annealing to obtain full ferritic matrix. Then, the samples were partially austenitized at 870 ?C for 10, 15, and 20 minutes, followed by austempering in a molten salt bath at 350 ?C for one hour. After it, samples microstructures were examined with an optical microscope. In the next step, electrochemical corrosion tests were performed with Tafel polarization method. Then, by preparing notched and smooth C-ring samples, the loads leading to their failure were determined under the bending tests in air. Finally, the behavior of C-ring samples in corrosive caustic soda solution were investigated under bending loads. According to the obtained results, with the increase of the partial austenitizing time, the ausferrite phase fraction increased according to the JMAK equation. The creation of dual matrix structure of ferrite-ausferrite caused the corrosion resistance of the samples to be weakened compared to the samples with fully ferritic matrix and conventional ADI. As the partial austenitizing time increased, the corrosion resistance, bending tensile strength in air and time to failure in corrosive media under constant load, increased. The bending loads leading to the failure of notched samples in air were significantly lower than those of smooth samples. The results of stress analysis in C-ring samples under bending test in air showed that the reduction of cross-sectional area, change the outer effective radius and neutral radius of the samples, and stress concentration are three contributing factors in reducing the tolerable bending load without occouranse failure with the contribution of 35%, 35% and 30%, respectively. The notch strength ratio (NSR) was independent of the effect of partial austenitizing time and it was about 0.87. All the smooth samples endured 100 hours of stress-corrosion testing under maximum applied loads (equivalent to 85% of failure load in air) without occurrence of failure. By decreasing the applied load in the corrosive environment, the time to failure of all samples increased greatly. There was a power relationship between the stress-corrosion threshold stress and the ultimate tensile strength of the samples. Also, during stress-corrosion testing the gradual fracture along with growth of cracks was not observed and failure of all samples in both environments air and caustic soda occurred via very rapid crack propagation in a completely brittle mode over the whole range of the applied loads.   

  هدف،

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

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

      In recent years and with the increase in the number of elderly people in different countries, the supply and demand for the use of titanium and its alloys in the manufacture of implants used in the human body such as hip joint prosthesis, joint replacement, knee replacement, fracture fixation and dental implants have increased.   has increased widely.   In medical applications, in addition to the usual properties of alloys, other factors such as topography and surface energy are also considered, which play an important role in the adhesion of bone cells to the implanted surface.   As a result, the surface of the material plays an important role in the body's response to the implantable material.   The purpose of this research is to investigate the effect of some variables of the sandblasting process, acid washing and heat treatment on the surface characteristics and cellular response of titanium.   In order to modify the surface of the titanium substrate, first the samples were sandblasted using alumina powder, then they were etched in a solution containing nitric acid and sulfuric acid for the necessary time.   After that, the samples were placed in the oven at temperatures of 300, 400, and 500 degrees Celsius for one hour. A group of samples were left without heat treatment.   In order to measure roughness, hydrophilicity, investigate surface morphology, investigate phase compounds, cytotoxicity and biocompatibility of substrates, various tests and equipment including roughness meter, water contact angle measurement system, XRD, cytotoxicity and SEM were used to investigate cellular morphology.   The results of the X-ray diffraction test showed that the dominant phase formed is the Ti6O phase.   Of course, a small amount of Ti2O3 was also formed.   The above groups cause better calcium deposition through reaction with body fluids.   And the results of the hydrophilicity test showed that the amount of wetting angle ?m decreased with increasing sandblast pressure and especially with heat treatment compared to the control samples.   However, in most of the samples, by increasing the temperature of heat treatment to 500 degrees Celsius, the contact angle has increased and the wettability has decreased.   Regarding the evaluation of cell viability, the produced levels did not show any signs of cytotoxicity.   In fact, the roughness of the surfaces obtained after sandblasting and acid etching were able to strengthen the attachment and proliferation of MG-63 cells on their surfaces.

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.  

Implant Insertion is not always successful, Because of inappropriate stability of implant-bone intersection. It seems implant geometrical including length, diameter, Number and depths flutes are affected on stresses and mechanical stability. The purpose of this research is study of implant geometrical variable such as numbers, angle and length of vertical grooves (Flute) on stress distribution and the amount of the implant displacement during static and periodic loads using finite elements Method (FEM) according to ISO 14801 international Standard. founded, that the effect of geometrical variables such as the length of the groove on the implant stem, the angles and Flute’s Number on the overall life of the dental implant and the amount of displacement after implantation has been very effective, so that the diagonalization of the groove has increased the tension better and its length is also more optimal in the original implant. Convergence of geometric variables such as alpha 6 degrees, beta 12 degrees, three grooves, with a fixed groove length will increase the life and stability of the implant by reducing the displacement of the implant in the anchor(bone). Since creating the final torque on the abutment causes the mechanical stability of the dental implant, the torque and loading couple will also stabilize the implant in the bone and increase its lifelog. When the abutment in the implant is tightened with a torque of 35 newton.mm. It causes more stability through more engagement with the surrounding bone.

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

   Abstract Today, pollution of aquatic ecosystems with a wide range of organic and inorganic pollutants has become one of the biggest human challenges, so that research studies examining techniques and the use of effective attractants in reducing and Or the elimination of some of these harmful pollutants, including arsenic, has many study priorities. The aim of this study was to optimize the adsorption conditions of arsenic heavy metal from water using magnetite-chitosan composite nanosorbent. The advantage of using chitosan coating is higher adsorption capacity and higher stability of adsorbent nanoparticles and its easy separation from aqueous solution. In this study, first magnetite nanoparticles were synthesized by co-precipitation method of iron (II) and (III) chloride ions and the obtained nanoparticles were first identified by FT-IR spectrum, then UV-Visible spectrum, TEM, XRD, VSM. , DLS, Zeta potential were obtained. After reviewing the results and obtaining the result, carboxymethylcytosans were sonochemically bonded to the surface of the modified magnetite nanoparticles and the surface of the magnetite nanoparticles was coated with carboxymethylcytosane. Magnetite-chitosan composite nanoparticles were taken by material analyzers, first FT-IR, UV-Visible, XRD which showed the presence of magnetite with chitosan coating, then TEM, VSM images, magnetic saturation change of nanoparticles after coating Delivery, DLS particle size distribution and Zeta potential surface load were investigated. Then, the adsorption test was performed using Design Expert software and the experiment was designed with Taguchi model from four factors: adsorbent dose, pH, temperature and time, and arsenic solution with an initial concentration of 1 ppm. Residual arsenic concentration was measured by ICP-Mass and statistical operations were performed on the test results and the effect of various factors on the adsorption efficiency was shown as contours so that the adsorption efficiency increased with increasing adsorbent dose and with increasing pH of The adsorption efficiency increased from 3.5 to 8.5 at a certain dose and the increase in temperature and time also increased the adsorption. Dose was 0.0300 g and pH = 3.5, contact time was 1440 min and temperature was 35 ° C. The optimal absorption point with 99.3% yield was obtained at a dose of 0.0283 g and pH = 6.4, and the contact time was 976 min and the temperature was C38, and the validation test showed a value of 99.4%. The weight ratio of chitosan to magnetite was synthesized in four different ratios of 1: 1, 2: 1, 3: 1 and 4: 1, and in optimal adsorption conditions, a test was performed. . Using the linear, nonlinear Langmuir equations and then the linear and nonlinear Friendlich isotherms, the isotherm that was consistent with the adsorption process and showed the highest correlation coefficient was the linear Langmuir and Friendlich isotherms, which obtained the maximum absorption capacity from the equation. The magnetite-chitosan composite was calculated to show 313.57 mg / g. According to the obtained results, the synthesized nanocomposite can be used for water filtration and arsenic adsorption under optimal conditions.

   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.

One of the most important issues in welded parts is the existence of residual stress due to the heat distribution. In this research the effect of residual stress on the energy absorption of steel tubes due to spiral welding, using various parameters such as the number of spirals and welding current intensity, in the manner of experimental/simulation has been studied. The compressive test has been used in order to determine the amount of energy absorption in the welded tubes. Also in the numerical simulation, the spiral welding process, heat distribution, residual stress distribution, tube folding and the force-displacement diagrams has been investigated. At the end, the results of experimental tests and numerical simulation has been compared and analyzed.   

اين تحقيق به منظور نشان دادن تاثير زواياي گوشه و هندسه گودبرداري بر روي تغييرشكل­ ها و سطوح گسيختگي اطراف گود ميخ­ گذاري شده، انجام شده­است. در اكثر تحقيقات صورت گرفته به بررسي و تحليل عناصر پايدارسازي ديواره‌ي گود با فرض كرنش مسطح و به‌صورت مسئله دوبعدي پرداخته شده­ است، حال آن‌كه مسئله‌ي پايداري در گوشه‌هاي گود و اثرات هندسه و شكل گود از جمله موضوعات مهم و تاثيرگذار بر پايداري و كنترل تغييرشكل‌ها و سطوح گسيختگي مي­ باشد. در اين تحقيق از نرم‌افزار اجزاء‌محدود Abaqus CAE-2016 استفاده شده و مدل­رفتاري مورد استفاده در اين تحقيق موهر-كولمب در نظر گرفته شده ­است. عمده تمركز اين تحقيق بر تغييرشكل سه ­بعدي گود و نشان دادن اثر گوشه‌ي گود است به همين منظور بررسي تغييرشكل‌هاي افقي و قائم گود و سطوح گسيختگي آن انجام ‌مي‌گردد. در اين تحقيق براي بررسي اثر هندسه و گوشه گود، 4 حالت مختلف براي گوشه گود در نظر گرفته ‌شده ­است؛ حالت گود مقعر با زاويه­ ي گوشه 60درجه، 90درجه، 120 درجه و حالت گود محدب با زاويه ­ي گوشه 270 درجه؛ كه براي هر كدام از حالت‌هاي ذكر شده از سه مدول الاستيسيته مختلف براي ميخ‌ها بررسي گرديده كه بتوان تاثير همزمان بازدارندگي گوشه گود را با تغيير مدول الاستيسيته ميخ‌ها بررسي كرد. با استفاده از تحليل­هاي عددي اثر مدول الاستيسيته و اثر زاويه گوشه گود بر‌روي تغييرمكان‌ها و نشست‌هاي ايجاد شده با فاصله گرفتن از سطح ديواره‌ي ميخ‌گذاري شده و تغييرشكل ديواره گود در گوشه‌هاي گود با ديوار ميخ‌گذاري شده و محل سطوح گسيختگي بحراني در حالت سرويس مورد ارزيابي قرار مي‌گيرد. در اين تحقيق بار سرويس متشكل از بار يكنواخت 135kpa بر روي سطح كل گودبرداري است. كه نتايج كلي مشهود از اين تحقيق، تاثير بازدارندگي گوشه‌هاي گود مقعر مي باشد، به‌طوري كه هرچه گوشه گود داراي زاويه‌ي كمتري باشد اين تاثير بازدارندگي در نشست‌هاي سطحي و تغييرمكان افقي ديواره­ي گود بيشتر است اما با كم شدن بيشتر زاويه گوشه اين تغييرات كمتر شده و بهينه نيست، بهترين زاويه كه تاثير بازدارندگي بهينه را دارد زاويه 90 درجه مي­باشد. براي حالت محدب عكس اين موضوع اتفاق مي‌افتد و اثر تحدب در گوشه باعث ناپايداري در گود افزايش در مقدار نشست‌ها خواهد­شد. تاثير سختي ميخ‌ها نيز مشابه تاثير گوشه گود است به طوري كه با افزايش سختي، كاهش در مقدار نشست‌هاي سطحي و تغييرمكان افقي ديواره­ ي گودبرداري مشهود مي‌گردد. در حالت محدب كه گود به حالت ناپايداري نزديك مي‌شود مي توان با ميخ‌هايي با سختي زياد اين اثر افزايش نشست را   تا حدود زيادي كاهش داد. كرنش­ هاي برشي پلاستيك باعث ايجاد 2ناحيه در گودبرداري مي­گردد،­ با نزديك شدن به گوشه گود، ناحيه 2 كه ناحيه­ اي فعال و محرك است به تدريج از ناحيه 1 كوچك‌تر شده و گود پايدارتر مي­گردد، اين اثر زاويه گوشه بر روي گوه­ هاي گسيختگي به اين شكل است كه با كوچك‌تر شدن زاويه گوشه تا 90درجه اين تاثير چشم گير است اما با كاهش بيشتر آن تغيير زيادي نسبت به مدل 90درجه مشاهده نمي­ گردد. براي حالت محدب نيز گوه­ هاي گسيختگي بسيار به لبه گود نزديك شده و حالت بحراني رخ مي­ دهد.

Neonates and infants are the most likely group to present with congestive cardiac failule, one of the most cause of mortality in newborns, so that, one out of 125 are born ech year with some form of heart failure. This cardiac failure ranges from mild to severe in terms of severity.In has been well established that the early diagnosis of cardiac disease in the embryyonic period may prevent the cardiac failures after birth and consequently decrease the rate of mortality in newborns.Recording heart electrical activity by electrocardiogram is commonly used to detect abnormal arrythmias. How ever the non-invasive extraction of fetal ECG   from maternal abdominal is challenging, since the fECG signals are aften corrupted by electrical noise from other sources such as maternal heart activity, uterine contractions and respiration, in addition to instrumental noise.Many approaches has been presented to non-invasively extract fECG, However their performance are not entirely satisfactory. Among all exising methods Blind Sourse Seperation have been of great interest to researchers for many applications. In this thesis, we use the method of time-frequency based blind source separation method for the separation of Convolutive Mixtures. We also use the Compressive sensing and the fast independent component analysis method to reduce the complexity of the signal.We apply our proposed method to the database in the 2013 Physionet Challenge and compare the results with existing methods using Compressive Sensing and Independent Component Analysis, which yielded a Mean squar Error of 171.65 and a time of 7.85 minutesKeywords: Fetel Electrocardiogram signal, Blind Source Seperation, Time-frequency analysis, Convolutive Mixtures, fast independent component analysis, Compressive sensing, Discet Wavelet Transform

شبيه سازي رشد ترك در چدن نشكن آستمپر شده تحت سايش خستگي

دو عامل اصلي در صدمه ديدن سازه ها و محتويات آن ها در حين زلزله، تغييرمكان هاي نسبي و شتاب هاي ايجاد شده در سازه هستند. طرح هاي لرزه اي همواره به دنبال كاهش اين دو عامل و درنتيجه كاستن خسارات وارده مي باشند. جداسازي پايه در سازه ها به طور همزمان موجب كاهش قابل توجهي در مقادير تغييرمكان هاي نسبي و شتاب هاي ايجاد شده در سازه مي شود و لذا با كاربرد سيستم جداسازي لرزه اي علاوه بر امكان طراحي يك سازه مطمئن مي توان به عملكرد اجزاي غيرسازه اي و محتويات سازه نيز در موقع زلزله مطمئن بود. تحقيقات نشان داده اند كه استفاده از ميراگرهاي ويسكوز مي تواند نقش موثري در كنترل پاسخ سازه ها در برابر باد، انفجار و زلزله داشته باشد] 2و1 [. اكثر سازه ها هنگام زلزله هاي شديد با كمك شكل پذيري اعضا با آن مقابله مي نمايند كه سبب آسيب هاي اساسي و بعضا غيرقابل جبراني به اعضاي سازه اي و غيرسازه اي مي گردد. استفاده از ميراگرها مي تواند تغييرمكان ها و شتاب هاي زياد سازه و به تبع آن نياز به شكل پذيري را كاهش دهد. در حال حاضر كشورهاي پيشرفته با مناطق زلزله خيز مانند ايالات متحده، ژاپن و نيوزيلند پيشگامان استفاده از جداسازي لرزه اي در جهان هستند و جداسازي پايه در سازه ها به عنوان رويكرد جديد مقاوم سازي لرزه اي مطرح شده و جنبه عملي به خود گرفته است. در كنار اين رويكرد بسترهاي تحقيقاتي فراواني به وجود آمده است كه تمام مراحل توليد تا اجراي سيستم هاي جداساز را شامل مي شود و تحليل ديناميكي سازه هاي جداسازي شده يكي از مهم ترين اين بسسترها است.مي دانيم كه پيچش اثر معكوس بر پاسخ سازه هاي مرسوم همچنين سازه هاي جداسازي شده مي گذارد. به دليل آنكه 42% تخريب ها در طول زلزله 1985 در شهر مكزيك بخاطر پاسخ پيچشي ساختمان هاي نامتقارن بود، آيين نامه فدرال مكزيك(2و1) اين فلسفه طراحي را   براي سازه هاي مرسوم، از سال 1987 معرفي كرده اند و ديگر آيين نامه هاي مكزيكي مثل منيول سازه هاي مهندسي در اين فلسفه سهيم اند. طبق اين فلسفه اگر خروج ازمركزيت هاي پلان محاسبه شده براي هر طبقه   از 10% بعد پلان در جهت داده شده بيشتر باشد به عنوان سازه هاي نامتقارن طراحي شود و اگر خروج ازمركزيت از 20% بيشتر شود آن ها بايد به عنوان سازه هاي شديدا نامتقارن طراحي شود.هدف اين پايان نامه بررسي اثر جداسازي پايه بر سازه هاي نامتقارن جرمي است. به اين منظور سه مقدار خروج از مركزيت جرمي 10% ، 20% و 30% در سازه با پاي ثابت و سازه جداسازي شده در نظر گرفته شد و پاسخ تغييرمكان هايشان با هم مقايسه شد. جداسازي اثر پيچش را در سازه به ميزان قابل توجهي كاهش مي دهد. جانمايي جداساز و ميراگرها به گونه اي تنظيم شد تا در هر خروج از مركزيت جرمي، مركز سختي و ميرايي سيستم جداسازي در گام هاي 5% درصدي روي محوري كه از مراكز جرم مي گذرد تغيير كند. سپس پاسخ تغييرمكان روسازه و زير سازه در تمام اين حالت ها تحت 7 شتاب نگاشت منتخب مطالعه و با هم مقايسه شدند. در واقع هدف از مطالعه جانمايي جداسازها و ميراگرها، بهينه كردن تغييرمكان هاي روسازه و زيرسازه به صورت همزمان است، به گونه اي كه جداسازي به بهترين نحو پاسخ هاي سازه نامتقارن جرمي را به سازه متقارن نزديك كند.واژه هاي كليدي: سازه هاي نامتقارن جرمي، جداساز لاستيكي با هسته سربي، ميراگر ويسكوز غيرخطي، تحليل ديناميكي غيرخطي، سازه جداسازي شده

طراحي و ساخت ماشين نورد نامتقارن ورق هاي فلزي

study

  In this research, utilizing transient liquid phase (TLP) joining for bio as-cast Co-28Cr-6Mo alloy similar bonding was investigated. Due to the good abrasion resistance, high mechanical properties, adequate corrosion resistance, high biocompatibility, as well as lower prices than gold base alloys, these alloys are the most suitable for biomedical applications. To this end, the TLP connection was performed using a MBF-100 cobalt-based and MBM-60 nickel-based interfacial layer with a thickness of 25 microns under argon gas atmosphere conditions at 1175 ?C and 15 min, and 1160?C and 60 min, 1170?C and 30 minutes , 1170 ?C and 60 min, and 1170 ?C and 120 min. The MBF-60 nickel base MBF-60 interface was also subjected to ambient atmospheres and vacuum of   torr at 950, 1000, 1050, 1100, 1170 and 1240 ?C.In order to test the mechanical properties of bonding, the bonded specimens were subjected to cutting tests. The results showed that the bond strength of MBF-100 interlayer at 1170 ° C and 2 h had the highest shear strength. The strength of sample bonding was reached 81% of base metal. Also, the effect of complete thermal solvent treatment at 1240 ° C and 4 h on shear bond strength was investigated. It was observed that at the same temperature and time, the complete solution sample had a higher strength than the bonding of as-cast samples in similar conditions. The highest bond strength was   for MBF-60 at 1000 ° C and 2 h.Investigation of microstructural analysis of the bonding was done using optical microscope and scanning electron microscopy (SEM) and SEM-EDS analysis results. The results of the bonding samples of 1175?C and 15 min using MBF-100 interlayer indicated that the melting was done on the boundaries at a bonding. By increasing the bonding time to 2 h at 1170?C, the penetration rate expanded, resulting in uniformity of the bonding region compounds and reduction of the phases present in the bonding region, indicating the expansion of the isothermal solidification zone. Boride compounds were also found in this sample indicate their stability.In joining studies conducted with the MBF-60 interlayer, it was found that in the bonding sample at 1000 ° C and 2 h, according to the EDS analysis the compounds were isolated as Cr3P3, Crp, Cr12P7, and CoP, and the phases Spherical is also seen in the DAZ zone. At temperatures, 1170° C was also observed continuous eutectic compounds at the center of the joint. The standard homogenization carbides dissolution process was carried out at 1240 ° C for 4 h the temperature for 4 hours. According to the microstructure bonding, the undesired phases of the bonding zone were significantly reduced and the homogeneity was observed. At this temperature, the carbides were completely dissolved and the granularity formed in the bonding zone.  

  The Ti-6Al-4V alloy with good tribiological characteristics, low elastic modulus, high strength to weight ratio and the Co-Cr-Mo with excellent resistance to corrosion and erosion, are practical as metal bio-materials in artificial joints. The Co-Cr-Mo alloy leads to reduced corrosion in the thigh joint and the Ti-6Al-4V alloy easily pairs up with surrounding bones and is therefore preferred for thigh stem. To build such a bimetal system, given the disparity of welding parameters, connection is a big hurdle. Different welding methods such as fusion welding, laser welding, hard and soft soldering, and penetration bonding for simillar and disimillar bonding of these alloys have been used. In this study, the transient liquid phase   rocess has been used for the Ti-6Al-4V/Co-Cr-Mo dissimilar system in order to address the shortcomings of other welding methods and access mechanical properties comparable with base metal. In this method, samples were cut as cylinders with 8 mm in diameter and 5.7 mm in height and their surfaces were prepared for bonding. An copper interlayer was placed between the two surfaces as covering on cobalt sample, and a constant pressure of 1 MPa was applied to the samples using fixture. Next, the bonding set was exposed to heating in under-pressure stove with the different temperatures of 925, 950 and 975, considering the eutectic temperature of Ti-Cu (about 875 °C), for 5 to 120 minutes. On the connected samples, cross section cut was performed and the substructure was studied using optical microscope. Results suggested that as a result of the bonding, 3 zones of DAZ (diffusion-affected region), ASZ (athermally solidified zone), and ISZ (isothermally solidified zone) appear in the bonding point, with the length of these zones differing depending on conditions of performing the bonding, and as joint temperature and duration increases, the athermally solidified zone can be removed, thus leading to progressed isothermally solidification during the bonding. Cut test was used to investigate mechanical strength of the samples, with the maximum shear strength equal to 350 MPa, which is around 50% of the base metal, obtained for the bonding made at 950 °C and in duration of 2 hours. Also, the failure level of the samples was identified with the X-ray diffraction test and failure level combination was considered. Type of failure and elements present in different phases of sample cross-sections were investigated using scanning electron microscopy. Elements constituting present elements were identified via the EDS test, and element changes in the sample were obtained with linear analysis. Keywords: transient liquid phase (TLP), Ti-6Al-4V, Co-Cr-Mo, evaluation of microstructure, mechanical properties, copper interlayer  

<  gt;توليد كامپوزيت زمينه آلومينيومي تقويت شده با شبكه سيمي فولادي</P>

Abstract:  The pipelines that are used in the petroleum industry tra  ort gas and oil with content of sulfidric gas that intensifies the adsorption of hydrogen in the metallic surface provoking the absorption of hydrogen in the wall of the pipe, what can flow in a embrittlement processThe welding process and the manufacturing process can also facilitate entry of hydrogen into the steel.The work done by other researchers suggest several parameters in the hydrogen losses had an impact. For example, have shown that the microstructures ferritic microstructure of ferrite needle more resistant to damage by hydrogen. Also tempered martensite microstructure bainite structures to very fine particles, perlite and martensite shows better behavior. Impurities and inclusions as trapping hydrogen in steels resources to act. Manganese sulfide is known as a harmful impurities.In this project, API 5L X60 pipes used in oil refineries Ntg Bijar area Kermanshah related to oil and gas companies have been defeated West under analysis. It was found that impurities MnS significant role in the formation of cracks were HIC. So that all EDS analysis show the presence of these impurities left in the region. Studies also show that the microstructure of the steel microstructure ferrite - pearlite with a hardness of 210 Vickers is that in some parts of needle ferrite and ferrite Weidman Ashtatn was observed in some areas.

Nowday injuries of hard tissues, forcing us to replace and fix them. In this regard, metal implants and among them titanium and its alloys has the most applications. In order to improve the biocompatibility and bioactivity of them, calcium phosphate coatings, especially hydroxyapatite, on which they are applied. The presence of silver ions in the structure of hydroxyapatite signifcatnly reduces the implant site infections, because of its antibacterial properties. Fluorine ions that are normally present in bone structure, in addition to improving the biocompatibility also have antimicrobial effects.   A composite coating containing silver, fluoride and hydroxyapatite (Ag-FHA) was developed on titanium substrate by sol-gel method. Triethyl phosphite, hydrated calcium nitrate, ammonium fluoride and silver nitrate were used respectively, as P, Ca, F and Ag precursors with a Ca:P ratio 1.67 and concentration of silver was 0.3 wt.%. Coatings were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and Atomic absorption spectrometry (AAS). Results showed that in presence of such a low concentration of silver in hydroxyapatite can’t make significant changes in its structure. In presence of fluoride the crystallite size reduced from 29 to 11 nm and the films, with 1.3 micrometers thickness, showed a uniform and dense morphology. Corrosion behavior in SBF at 37 °C showed that the corrosion resistance of coatings increased with increasing the amount of fluoride. Antibacterial activity of coatings against Escherichia coli indicated a significant enhancement in the antibacterial property of Ag-FHA nanocomposite with increasing the amount of fluoride. These coatings can prevent the bacterial infections of implants