saeed daneshmand

Nowadays, the use of bimetallic laminates with special capabilities and features is increasing and has experienced high growth. These properties include high mechanical properties, corrosion resistance, light weight, resistance to noted good abrasion and thermal stability. In the midst of the technologies of multilayer composite materials Accumulative Press Bonding (APB) is one of the most common techniques for the production of multilayer composites. One of the most important aims for this choice is the press pressure, which can create a strong and suitable mechanical connection between Produced metal layer components. In this study, the Accumulative Press Bonding method has been used to produce aluminum and copper composites and the process modeling has been done by ABAQUS finite element analysis software. In this paper, the effect of Press parameters such as strain and number of layers on the distribution stress of forming this type of composites has been investigated. Shear stress among the layers reached to about 4MPa for samples with eight layers which is a good condition to generation a successful bonding.  With increasing thickness, the stress applied on the layers has also increased. Maximum stress also increases significantly. As the thickness decreases, the interlayer shear stresses also increase. With increasing percentage of thickness decrease, the amount of sinking of the layers in each other has greater than before, which has led to the crushing of copper layers along the entire length of the sample. During the process, as the number of passes increases, the volume of virgin material in the direction of the press rises, which leads to increased compaction and better adhesion of the layers to each other.

To fabricate ultra-fine grain structures containing high strength, accumulative roll bonding is a kind of severe plastic deformation (SPD). In the present study, magnetic Al/ Fe2</sub>O3</sub> composites reinforced with 0, 2.5% and 5Wt.% of Fe2</sub>O3 </sub>particles have been manufactured via ARB. A uniform distribution of Iron oxide particles was achieved after the 8th</sup> cycles of ARB. Mechanical properties include (hardness, elongation, toughness) and also, magnetic and electrical properties such as magnetic saturation, magnetic permeability and magnetic residuals were studied. The presence of Fe2</sub>O3 </sub>particles improved the mechanical, electrical and magnetic properties of this kind of laminated composites. Vibrating sample magnetometer was utilized to study the magnetic properties of samples vs No. of steps.

Metal matrix composites, high mechanical performance, usability at high temperatures, good wear resistance and low creep rate. This type of composite manufacturing method is very important. Among manufacturing processes, ARB process as a method of applying severe plastic deformation is used on the sheets. In this study 5Wt. % Al/alumina composites fabricated by accumulative roll bonding process up to eight steps using Al1060. Microstructure, mechanical properties and corrosion behavior of the composite were studied by scanning electron microscopy (SEM), potentiodynamic polarization and electrochemical impedance spectroscopy (EIS), measurement in 3.5wt% NaCl solution. Corrosion behavior of the composite revealed a considerable improvement in the main electrochemical parameters, as a result of enhancing influence of cold rolling. Also, the electrochemical experiments showed that corrosion resistance of samples increasing with increasing the number of ARB cycles. After 8- cycle ARB have a low corrosion density in comparison with high corrosion density of annealed specimens.

Needle graphite electrodes are one of the main parts used in electric arc furnaces. These electrodes have a significant impact on melt quality and product quality, and their consumption is one of the most important parameters of steel production cost in EAF furnaces. Therefore, reducing the consumption of needle graphite electrodes in these furnaces is very important. The main reasons for continuous use of needle graphite electrodes in arc furnaces are oxidation of the sidewalls and sublimation of their tips, and many solutions have been proposed to reduce them. In the present study, the effect of coating consisting of TiO2/SiC/SiO2 elements on the wear rate of the needle graphite electrode in the sublimation state is investigated using EDM (Electrical Discharge Machining- Spark device). For this purpose, the effect of voltage, current, pulse on time and pulse off time on the electrode wear rate are investigated and in this regard, Taguchi design method has been used to reduce the number of experiments. Based on the test results, TiO2/SiC/SiO2 coating reduces the wear rate of the needle graphite electrode due to sublimation.

Nowadays, due to population growth, urban development and lack of fresh (drinking) water resources, the discovery of new ways of water production is of great importance. One of the new methods of producing the drinking (fresh) water at low capacities is the use of air humidity, which is known as condensed water production system. In the present research, drinking water production systems have been studied with the aim of obtaining the optimal length and evaluating the parameters affecting the amount of water produced in condensed systems. The obtained results show that 2.1 Kg water/day will be approximately extracted with considering D=0.2 m,y=0.5 m,L=15m,T_i=70 ℃,H_r=70 %. Sensitivity analysis has been also performed on various parameters and soil type. The obtained results of this analysis also show that air temperature and relative humidity have the greatest effect on the amount of produced water, and also sand, gravel, wet soil and clay produce the highest amount of water respectively. So, this research work may be beneficial and useful for human comfort and convenience. Finally, suitable and good results are obtained by the proposed method.

In this study, NiFe2O4 nanoparticles, with respecting two variables, were prepared through co-precipitation. These two variables are the temperature gradient reaching the temperature of the heat treatment of 500 °C at 10°C/sec, 35°C/sec and 60 °C/sec and the pure oxygen pressure as the heat treatment atmosphere for one hour, at 0.5 psi, 1 psi, and 1.5 psi. So, we found 9 samples, that the sample with the best sensitivity response to formaldehyde (sample with 10°C/sec heat treatment and 1 psi pure oxygen pressure) was characterized. X-ray diffraction (XRD), scanning electron microscopy (SEM), transition electron microscopy (TEM) and X-ray fluorescence (XRF) experiments were used to study the structure of these nanoparticles. X-ray diffraction experiment has verified formation of nickel ferrite phases. Furthermore, scanning electron microscopy and transition electron microscopy experiments confirmed that the ferrite was indeed a nano-structure. Finally, NiFe2O4 formula ratio was derived by X-ray fluorescence experiment. The sensitivity property of NiFe2O4 nanoparticles for formaldehyde gas detection was studied at 100 °C. For testing the sensitivity of nanosensors, a laboratory 5 liters system was used with temperature and humidity control. This system equipped with a temperature control heater for heating sensors. Relationship between gas concentration (from 20 ppm to 200 ppm) and resistance change of nano sensor with the best response to formaldehyde was investigated.

In order to improve the performance of the ejector systems, this research has been conducted with the purpose of validation and thermodynamic analysis of multi-stage ejector refrigeration cycle in car cooler using combustion heat. For this purpose, one of a variety of combined ejector cycles using a numerical flow method inside a refrigeration cycle, and role of operating parameters, operating fluid, and throttle diameter of the mixing chamber were studied. The obtained results show that the use of a multi-stage oscillation cycle with an increase of 10% to 15% of the coefficient of performance, compared to the simple cycle of inclination. Also, the obtained results indicate that the R12 fluid has the highest coefficient of performance COP but will have effects on the ozone layer and is better than other refrigerants used. It seems that considering the low cost of maintaining the two-stage ejector refrigeration cycle is very suitable alternative for other cycles in different applications. Given the using two ejectors instead of a compressor and using automobile heat dissipation as the energy needed to start the cycle can save up to 35% of energy consumption, as most of the energy in the cooling cycle is consumed by the compressor. Due to the size of the ejectors in this cycle and considering the creation of a suitable space for fitting it inside the car hood, there is no particular problem and can be used massively and extensively in the automotive industry to create cooling.

Recently, with reducing the energy resources and increasing the energy costs (price), the energy saving has been attracted any more. Pinch analysis of an industrial process has been employed to identify pinch point and energy price together with heat exchanger network cost. To do so, we simulate the refinery process using Hysis software and analyze the results with Aspen Energy Analyzer. After validating the model using field data, simulated model was studied. The results showed with 1.7E04 $ investment, 31492$ will be returned annually using modified retrofit network. The payback time would be 180 days. In this paper, the Pinch Point is investigated and analyzed at various temperatures using Aspen Hysis software and Aspen Energy Analyzer software. In addition, economic calculations related to operating costs (energy) and total costs have been done. With the modification of the above-mentioned heat exchanger network, notable saving will be earned for the mentioned organization. So, the return period of capital will be approximately 180 days (less than one year) for the mentioned organization in this model.

.Nano-particles used in metal matrix composites show a various range of mechanical, chemical and physical features, causing significant improvements in mechanical strength, hardness and thermal characteristics. They can also change the capability of machining. Electrical discharge machining is considered as an integrate part of hard metal machining. In this paper, the parameters of electrical discharge machining for aluminum composite material improved by Nano-particles of titanium dioxide have been studied. The purpose of this study was to evaluate the impacts of electrical current and voltage and pulse on and off-time on the material removal rate, tool wear rate and surface roughness. Kerosene as a dielectric and copper electrode were used to carry out the experiment. In addition, Analysis of variance was utilized to authenticate the experimental results. The result shows that Nano-particles titanium dioxide has trivial effects on machining parameters due to being insulators. They also do not melt in the process of electrical discharge machining. Moreover, the electrical current and the pulse on time have the most influence on the material removal rate, tool wear rate and surface roughness. By increasing the electrical current and pulse on time, tool wear rate and surface roughness have grown, while by increasing the pulse off time tool wear rate has decreased. The average wear rate of the electrode in the aluminum alloy 2024 reinforced with 5% titanium oxide nanoparticles is 46.3%, equivalent to 0.346 gr, more than the weight loss of the aluminum 2024 specimen.

Metal matrix composites, according to the type of reinforcement used, have a different machinability. 2024 Aluminum matrix composites reinforced with aluminum oxide is among the materials the machining of which through traditional methods leads to the rapid wear of the tool; hence, EDM is a suitable method for machining this class of materials. Given that this machining method has different parameters, optimal set of machining parameters has a major effect on machining time, surface quality and tool wear rate. Using calculation and analysis of the total normalized quality loss (TNQL) and simultaneous signal to noise ratio of the outputs, this research is an attempt to investigate the effect of EDM parameters including current intensity, voltage, pulse on-time, and pulse off-time on material removal rate, tool wear rate and surface roughness in a the states of with and without powder and rotary tool. The results showed that current intensity and then pulse on-time, pulse off-time, and voltage have respectively the most important effect on output parameters of machining. The use of aluminum oxide powder and rotary tool increases gap and creates a centrifugal force and hence moves particles away from the area of machining and finally increases MRR. The use of aluminum powder in collision with sparks makes the sparks smaller and reduces their penetration depth and, thus, reduces the surface roughness. The results of optimization without powder and rotary tool proposes the combination of parameters as A3B1C2D3 while with powder and rotary tool proposes the combination of parameters as A1B1C2D3.

Nowadays, we live in a world which quality, speed, accuracy and cost are the most important parameters in part's design and manufacturing. Due to the complexity of part manufacturing, traditional and nontraditional manufacturing techniques are used. Aerodynamic tests usually requires one or several models for testing in wind tunnels and these models typically have particular complexities in which necessitates different techniques such as machining, casting or rapid prototyping in order to manufacture them; However, these techniques imply certain advantages and disadvantages. Selection of an optimal method affects the results and quality of manufacturing. In this study, the surface roughness experimental effect of a projectile on its aerodynamic coefficients is investigated. For this purpose, three projectiles with three levels of high, medium and rough surface quality were built and analyzed in different angles of attack and velocities, the aerodynamic coefficients and the ratio of lift to drag. The results indicated that at high velocities and high angles of attack, it is better to use a model with the highest surface quality because it reduces the drag and increases the ratio of lift to drag, thus has influence on the aerodynamic coefficients and with increasing roughness, critical Reynolds number is also reduced.

In this study, as for the re-casting, surface alloying and re-solidification layer of this alloys at the work piece level machining with Wire Electro discharge machining (WEDM), changes of surface micro hardness with changes of operational parameters has been studied. Therefore, study shows using surface alloying phenomena with the diffusion of wire material into the machined surface and selection of operational parameters and suitable materials for wire cutting, surface mechanical properties can be modified simultaneously with the workpiece machining process. Also Shown in this study, by changing operating parameters such as peak power and open circuit voltage, the diffusion of wire material into the workpiece surface layer is increased, whereas with increasing pulse off time and dielectric flushing pressure, the diffusion of wire material into the workpiece surface layer is decreased. At last with increasing these parameters also change of micro hardness surface layer accompanied by a change alloy surface layer formed on the surface.

According to recent achievements in Nano technology we can see its effects in different engineering fields. In Nano manufacture process the first essential step is modeling coordinately in order to make it available different software are developing for this propose. In this paper Nano modeling for two papers is developed first understanding structure in Nano and micro size and second simulations of molecular movements in Nano size. In this paper fundamental concepts of both methods are discussed and MATLAB based software is developed for this purpose. In first step cubic and cylindrical shapes are modeled by the software then some simulations in which temperature’s effect modeled are presented. In second part a 2D model based on molecular dynamics is presented wit using this model we can find effects of force on AFM cantilever’s tip which has a great important in different Nano manufacture areas