The aim of the current study was to find a reliable Joint between Borosilicate glass and Kovar alloys. For this purpose, the Dilatometer test was applied to calculate the thermal expansion coefficient of glass and Kovar alloys, and the materials with lower differences in the thermal expansion coefficient were used to join the Kovar to glass. Due to the nonmetallic properties of glass, it is theoretically impossible to join glass to metal as it shows no wettability. Therefore, a material was applied as a sealer between Kovar and glass to solve this problem. The Kovar samples were oxidized in the N2-H2-H2O atmosphere to control the chemical composition and also form an oxide layer that does not contain Fe2O3. The tensile strength of the produced Joints was investigated at different times and temperatures. The results showed that the highest tensile strength was 16.63 MPa which was achieved at 10 min and 1000°C.

Mechanical behavior of articular cartilage is affected by many factors. Inhomogeneous distribution ofproteoglycans and collagen fibers through the thickness causes some depth-wise behavior. Mechanicalproperties directly affect stress and deformation of the tissue. In previous studies complexities andvariation in Mechanical properties were ignored. The aim of the present study is to create a model closeto real anatomy of articular cartilage in knee Joint and to simulate its behavior under dynamic gate in thestance phase.A 3D finite element (FE) model was created. It was constructed considering femur and tibialcartilages as well as medial and lateral meniscus. In the FE model, a nonlinear isotropic viscoelasticmaterial model was used for cartilages and linear anisotropic elastic one was chosen for meniscuses.Morever, cartilages were assumed saturated. Numerical simulations on the model showed that peak ofmaximum principal stress occurred in superficial layer. It was decreased through thickness. Thisexplains the existence of osteoarthritis in the exterior layers. The present study showed that hydraulicpermeability variation in cartilage as a strain-dependent variable was negligible in dynamic loading.Also, results showed good agreement with experimental ones.

Despite the increased use of aluminium alloys in several industries, their common concern is the difficulty of joining dissimilar alloys using welding techniques. Based on this, the primary purpose of this research is to assess the Mechanical characteristics of dissimilar joining of heat-treatable 6061 and non-heat-treatable 5083 aluminium alloys by gas tungsten arc welding and to discover the link between microstructure and Mechanical properties. Similar welds were also implemented and evaluated in order to more properly analyze and compare the outcomes. The quality of the weld generated after establishing the health of the Joint using non-destructive testing was evaluated by destructive bending, tensile, metallographic, and hardness tests to check the Mechanical and microstructural qualities. The intended dissimilar weld was produced under the parameters of pulse current 120-80 amps, voltage 20 volts, welding speed 15 cm/min, and filler 5356. It should be highlighted that the dissimilar weld had the maximum Joint efficiency, and with perfect control of welding settings and the absence of flaws, only 36% loss of strength was recorded when compared to the base metal. Metallographic images revealed that the formation of hot cracks in the dendritic structure of the weld metal is the major cause of strength loss for 5083 similar weld and the production of numerous porosities in the weld metal for 6061 similar welds.

Objective: The goal of the present study was to improve the extension and flexion of the elbow Joint for rehabilitation purposes, in terms of energy dissipation and of injuries caused by stress imposed on connective tissue by exercise equipments during force transfer, by investigation of viscoelastic property variations during change in speed of motion.Materials & Methods: A sample of five men without any previous neuromuscular impairment of the elbow Joint was chosen by the BMI factor. The passive continuous motion test (CPM) was performed by the CYBEX isokinetic system in the extension and flexion movements of the elbow Joint of the left hand, at 4 different speeds (15, 45, 75 and120 Deg/s) during 5 consecutive cycles at the range of motion of about 0 to 130 degrees.The experimental data was exported to the MATLAB software for analysis. In order to determine viscoelastic property effects and bioMechanical parameters, we used a passive viscoelastic Mechanical model constructed by 3 elements for simulation, and also we used the curve fitting method to derive the elastic and viscose coefficients for the model.Results: Results of experiments showed that by increasing the speed of motion, the value of work done, hysteresis and elastic coefficient increased and the value of viscose coefficient decreased. Also, it appeared that by increasing the speed of motion, the effect of viscose resistance on the passive torque curves increased. In addition, there was significant correlation between the action of the Mechanical model and the action of the concerned limbs, during the movement.Conclusion: It was concluded that in order to improve motion and to reduce imposed risks and injuries to Joints and limbs, rehabilitation exercises better be performed at lower speeds and with rehabilitation equipments supported by viscoelastic resistant force.

In this study, the effects of sodium hydroxide solution concentration and sodium hydroxide to sodium silicate weight ratio on compressive strength, tensile strength, and elastic modulus of slag-based geopolymer concrete are investigated. The results of the experiments show that by reducing the ratio of sodium hydroxide to sodium silicate and increasing the concentration of sodium hydroxide, the compressive strength and tensile strength of concrete increase. In addition, by increasing the concentration of sodium hydroxide and reducing the ratio of sodium hydroxide to sodium silicate, the modulus of elasticity decreases, and no clear relationship is observed between compressive strength and modulus of elasticity of geopolymer concrete. Therefore, a mix design with a ratio of sodium hydroxide to sodium silicate equal to 0.4 and a concentration of 6 molarity sodium hydroxide with the highest compressive strength was selected to be used for the second step of the research. The performance of beam-column Joints in past earthquakes shows their importance in the performance of concrete moment-resisting frames. Therefore, in the second step of this research, an experimental study is done for two beam-column Joints with geopolymer concrete and ordinary concrete. In order to investigate the cyclic behavior of the Joint, the experiment is performed according to the loading protocol of ACI 374.1-05. The results of the experiment show that the geopolymer concrete beam-column Joint has the acceptance criteria of ACI 374.1-05 regulations, and also, its seismic performance assures that the plastic hinge is generated in the beam properly.

Alarm systems are essential in safe operation of industrial plants. Since many process variables are interacting with each other, so in this paper, an approximate method is introduced to design and analysis of a multivariate alarm system. In this method, the alarm system is designed base on Joint indices. The Joint FAR and Joint MAR are defined for a m-variable alarm system thanks to multivariate Markov scheme. In proposed method, the alarm Joint indices are defined by solving a Linear Programing (LP) optimization problem. By defining Joint indices, tuning of the alarm parameters (like, threshold and etc. ) can be done by these indices instead of correlation analysis. In this paper, penalty scenario and Genetic algorithm are used for alarm generation, and parameter optimization in Tennessee Eastman (TE) Process. The results of proposed method are compared with other methods.