• XML

    isc pubmed crossref medra doaj doaj
  • List of Articles


      • Open Access Article

        1 - Characterization of SiO2-TiO2 Coatings on 316l Stainless Steel Substrates
        Manuel Gutierrez Martinez Lizangela Guerra Barbara Bermudez Reyes Roberto Cabriales Luis Reyes
        This paper reports nano-structured SiO2-TiO2 coatings using the sol-gel technique on 316L steel substrates. Nanoindentation, surface analysis and corrosion resistance tests were performed on different samples. The nanomechanical tests allowed to compare uncoated steel s More
        This paper reports nano-structured SiO2-TiO2 coatings using the sol-gel technique on 316L steel substrates. Nanoindentation, surface analysis and corrosion resistance tests were performed on different samples. The nanomechanical tests allowed to compare uncoated steel samples (Eavg = 193.24 GPa and mean hardness of 2.63 GPa and coated steel samples (Eavg = 287.38 GPa and mean hardness of 5.74 GPa), resulting into an improvement of the resistance and modulus of elasticity on the coated steel substrates. From a surface analysis an average thickness of 1.12 μm was obtained in the coated samples, presenting a dense and consolidated coating. Polarization resistance (PR) and electrochemical impedance spectroscopy (EIS) tests were performed. The PR tests showed a resistance of 2.11  105 (Ω cm2) for the uncoated steel, while the coated steel showed a resistance of 3.46  105 (Ω cm2), observing an increase in resistance compared to bare steel. The EIS tests showed greater resistance by the coated steel (5.8  105 (Ω cm2)) compared to the bare steel (2.8  105 (Ω cm2)). The effects of the electrolyte in both conditions were observed by SEM after immersion for 24 hours, showing pitting by the bare steel and good protection by the coated steel. Manuscript profile
      • Open Access Article

        2 - CORROSION BEHAVIOR OF BIOACTIVATED TITANIUM DENTAL IMPLANT USING DIFFERENT CHEMICAL METHODS
        Mohammad Khodaei Ehsan Khoda Bande Dastjerdi Hamid Nazemi Alireza Valanezhad Ikuya Watanabe
        At the past, damaged tissue was removed from the body of patients. But now tissue regeneration using scaffolds and implants are used to repair the damaged tissue and organs. Besides of the mechanical properties of metallic biomaterials, they suffer from bioinertness. Us More
        At the past, damaged tissue was removed from the body of patients. But now tissue regeneration using scaffolds and implants are used to repair the damaged tissue and organs. Besides of the mechanical properties of metallic biomaterials, they suffer from bioinertness. Using some surface treatment techniques, the bioactivity and also corrosion resistance of titanium implants could be improved. In this study the effect of H2O2 and alkali treatments on the corrosion behavior of titanium implant in the artificial saliva, surface morphology and phases formed on the surface, were investigated using electrochemical corrosion test, scanning electron microscopy (SEM) and thin film x-ray diffractometery (TF-XRD) respectively. Results indicated that on the surface of H2O2 and alkali treated titanium samples, fine particles of anatase and fine wire of rutile was formed respectively. The results indicated that the corrosion resistance of alkali treated titanium in the artificial saliva was higher than H2O2 treated titanium sample. The corrosion current density for untreated, H2O2 and alkali treated titanium samples were about 0.6×10-8, 5×10-8, 3×10-8 A/cm2respectively. Manuscript profile
      • Open Access Article

        3 - Optimization of die geometry for Tube Channel Pressing
        Mohammad Hassan Farshidi
        Since tubes have numerous industrial applications, different attempts are focused on the Severe Plastic Deformation (SPD) processes of tubes. As an illustration, Tube Channel Pressing (TCP) is an attractive process for this purpose since it can be used for processing of More
        Since tubes have numerous industrial applications, different attempts are focused on the Severe Plastic Deformation (SPD) processes of tubes. As an illustration, Tube Channel Pressing (TCP) is an attractive process for this purpose since it can be used for processing of different sizes of tubes. However, more attempts are needed to improve the outcomes of TCP. For example, imposing of greater strain besides reductions of strain heterogeneity are the challenges of this process. This work is aimed to optimize the die geometry of TCP in order to increase imposed strain as well as to decrease strain heterogeneity through an FEM simulation method verified by experiment. Results show that the increase of die curvature radius causes decrease of imposed plastic strain and increase of strain heterogeneity. In addition, the minimum amount of die convex height for imposing of reasonable strain through TCP is calculated considering tube thickness and channel angle. Besides this, the optimum die geometry is recommended in order to minimize the strain heterogeneity. Manuscript profile
      • Open Access Article

        4 - Editorial
        Editorial
        Editorial Manuscript profile
      • Open Access Article

        5 - Prediction of forging force and barreling behavior in isothermal hot forging of AlCuMgPb aluminum alloy using artificial neural network
        hamidreza Rezaei Ashtiani p shahsavari
        In the present investigation, an artificial neural network (ANN) model is developed to predict the isothermal hot forging behavior of AlCuMgPb aluminum alloy. The inputs of the ANN are deformation temperature, frictional factor, ram velocity and displacement whereas the More
        In the present investigation, an artificial neural network (ANN) model is developed to predict the isothermal hot forging behavior of AlCuMgPb aluminum alloy. The inputs of the ANN are deformation temperature, frictional factor, ram velocity and displacement whereas the forging force, barreling parameter and final shape are considered as the output variable. The developed feed-forward back-propagation ANN model is trained with Leven berg–Marquardt learning algorithm. Since the finite element (FE) simulation of the process is a time-consuming procedure, the ANN has been designed and the outputs of the FE simulation of the hot forging are used for training the network and then, the network is employed for prediction of the behavior of the output parameters during the isothermal forging process. Experimental data is compared with the FE predictions to verify the model accuracy. The performance of the ANN model is evaluated using a wide variety of standard statistical indices. Results show that the ANN model can efficiently and accurately predict isothermal hot forging behavior of AlCuMgPb alloy. Finally the extrapolation ability and noise sensitivity of the ANN model are also investigated. It is found that the extrapolation ability is very high in the proximity of the training domain, and the noise tolerance ability very robust. Manuscript profile
      • Open Access Article

        6 - Microstructure evolution and mechanical properties of Mo40/C93200 bimetal processed by compound casting process
        Mohammad Honarpisheh Mobin Javaheri Hadi mansouri
        Compound casting refers to a process that used to produce bimetals. This study investigates the interface of Mo40/C93200 that is produced by compound casting process. In this research, molten bronze is poured around steel core, interaction between liquid and solid creat More
        Compound casting refers to a process that used to produce bimetals. This study investigates the interface of Mo40/C93200 that is produced by compound casting process. In this research, molten bronze is poured around steel core, interaction between liquid and solid creates a diffusion zone and followed by a transition layer which leads to the creation of diffused region between the interfaces of metal layers. The results of micro-hardness and macro hardness used to complete the studies. The results of the hardness of the Mo40 alloy revealed that the micro-hardness of the alloy was almost 308 Vickers which this amount of hardness confirms the ferrite-pearlite state of microstructures. The results of metallography revealed that the boundary between steel and bronze alloys due to the difference in electric potential during etching evolved a galvanic cell and one section formed as the cathode and the other section as the anode. In this situation steel was corroding and bronze was protecting. As well as, the results of SEM show that the boundaries between two alloys have an acceptable adhesion and the strength of interface is sufficient. The result of tensile test indicates that the final yield strength was about 800 MPa and the elongation increases by 2%, which is an acceptable value. It is also observed that the failure is a soft defect type and a sufficient connection between steel and bronze is formed. Manuscript profile
      • Open Access Article

        7 - Investigation of Influence External Pressures on Vibration of Thin-Walled Cylindrical Shell Supported Composed of Functionally Graded Materials
        Mohammad Reza Isvandzibaei
        This paper presents the study on influence external pressures on vibration of functionally graded materials thin-walled cylindrical shell supported. The functionally graded materials (FGMs) properties are graded in the thickness direction of the shell. FGMs are advanced More
        This paper presents the study on influence external pressures on vibration of functionally graded materials thin-walled cylindrical shell supported. The functionally graded materials (FGMs) properties are graded in the thickness direction of the shell. FGMs are advanced composite materials, consisting of different types of materials, in which the properties shift continuously from one material on the one side to another material on the other side with a specific gradient. The FGM cylindrical shell supported equations with external pressure are established based on classical shell theory with beam functions as axial modal function. The governing equations of motion were employed, using energy functional and by applying the Ritz method. The boundary conditions represented by end conditions of the FGM structure which are sliding-sliding, clamped-free and clamped-simply supported being considered. This problem was solved with computer programming using MAPLE package. Comparison results are carried out to verify the validity with published papers. The influence of the external pressures, loop support and effect of the different boundary conditions on natural frequencies of FGM thin-walled cylindrical shell are studied. Manuscript profile
      • Open Access Article

        8 - Comparing the capability of various models for predicting of the Bayer process parameters
        Ahad Ghaemi Shahrokh Shahhosseini Mostafa Mahmoudian
        In the present study, prediction of Alumina recovery efficiency (A.R.E), the amount of produced red mud (A.P.R), red mud settling rate (R.S.R) and bound-soda losses (B.S.L) in Bayer process red mud has been carried out for the first time in the field. These predictions More
        In the present study, prediction of Alumina recovery efficiency (A.R.E), the amount of produced red mud (A.P.R), red mud settling rate (R.S.R) and bound-soda losses (B.S.L) in Bayer process red mud has been carried out for the first time in the field. These predictions are based on Lime to bauxite ratio and chemical analyses of bauxite and lime as Bayer process feed materials. Radial basis function (RBF) and Multilayer perceptron (MLP) as artificial neural networks and the multiple linear regression (MLR) method have been used to predict these parameters in the Iran Alumina Company. According to the obtained results, it is evident that the RBF method has outperformed the other two methods in the prediction of A.R.E, A.P.R and B.S.L. However the Multilayer perceptron (MLP) method can produce better and more precise results in the prediction of R.S.R. This research also exposes more effective variables on A.R.E, A.P.R, R.S.R, and B.S.L. Manuscript profile