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RISS 인기검색어
- 검색키워드
- 저자 : Erfan Zalnezhad (검색결과 6 건)
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Surface Hardness Prediction of CrN Thin Film Coating on AL7075-T6 Alloy Using Fuzzy Logic System
Erfan Zalnezhad,Ahmed Aly Diaa Mohammed Sarhan,Mohd Hamdi 한국정밀공학회 2013 International Journal of Precision Engineering and Vol. No.
In recent years, CrN coating has been identified as one of the most promising protective layers on surfaces of tools and dies due to its excellent mechanical properties, corrosion resistance, and surface hardness. This study presents the predicting of chromium nitride (CrN) coating surface hardness on AL7075-T6 using fuzzy logic technique. First, Al7075-T6 was coated with CrN at different parameter conditions, after which the surfaces hardness of the CrN-coated specimens was measured using a micro hardness machine. Next, a fuzzy logic model was established to predict the surface hardness of CrN coating on AL7075-T6 with respect to changes in input process parameters, DC power, temperature, and nitrogen flow rate based on the trained data obtained from the micro hardness test. Three membership functions were allocated in connection with each model input. Finally, five new experimental tests were carried out to verify the predicted results achieved via the fuzzy logic model. The results indicate an agreement between the fuzzy model and experimental results with 94.664% accuracy.
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Erfan Zalnezhad,Ahmed Aly Diaa Mohammed Sarhan,Mohd Hamdi 한국정밀공학회 2012 International Journal of Precision Engineering and Vol. No.
In this research work, predicting of titanium nitride (TiN) coating adhesion on AL7075-T6 is presented. First TiN was coated on Al7075-T6 in different conditions and the surfaces adhesion of TiN coated specimens were measured using micro scratch force machine. Second a fuzzy logic model was established to predict the of TiN coating adhesion on AL7075-T6with respect to changes in input process parameters, DC power, DC bias voltage, and nitrogen flow rate based on the tried data obtained from the scratch force test. Four membership functions are allocated to be connected with each input of the model. Third, new five experimental tests were carried out to verify the predicted results achieved via fuzzy logic model. The result indicated settlement between the fuzzy model and experimental results with the 95.534% accuracy.
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Investigation of Optical and Structural Properties of Ion-Assisted Deposition (IAD) ZrO2 Thin Films
Mansour Suker Farhan,Erfan Zalnezhad,Abdul Razak Bushroa 한국정밀공학회 2013 International Journal of Precision Engineering and Vol. No.
Zirconium dioxide thin films were deposited onto fused silica glass substrates by electron-beam assisted by oxygen ions using high vacuum coater equipped with electron beam gun at ambient substrate temperature. The properties of the films have been investigated using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), micro-hardness testing, laser induced damage threshold (LIDT) and optical analysis. It is found that the crystalline phase is strongly influenced by ion energy and current density and an amorphous to monoclinic transition is occurred. The changes in crystallinity resulted in increase in the film micro-hardness up to19GPa, revealed in minimum residual stress -2GPa. LIDT increased up to 19 J/cm2 and the optical refractive index improved up to 2.23 at 550 nm wavelength for films deposited at ion energy of 400eV and 100μA/cm2 current density.
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Hui Li,Xin Chen,Erfan Zalnezhad,K.N. Hui,K.S. Hui,Min Jae Ko 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.82 No.-
MXene has been considered as a promising two-dimensional material for supercapacitors owing to itslarge surface area, high conductivity, and excellent cycling stability. However, its low specific capacitancerestricts its extensive applications. Therefore, to address the issue, we homogeneously deposited NiCo2S4nanoflakes on the surface of MXene on conductive nickel foam (denoted as MXene-NiCo2S4@NF), whichwas used as a composite binder-free electrode for supercapacitor applications. The NiCo2S4 nanoflakesincreased the surface area of the composite electrode, thereby increasing its specific capacity from106.34 C g 1 to 596.69 C g 1 at 1 A g 1. Compared to the pristine MXene, MXene-NiCo2S4@NF maintainedthe high retention rate of pristine MXene and exhibited excellent cycling stability with 80.4% of its initialspecific capacity after 3000 cycles. The composite electrode exhibited improved electrochemicalperformance for supercapacitors, owing to the combined merits of NiCo2S4 (high specific capacity) andMXene (high retention rate and good cycling stability. The fabricated asymmetric solid-statesupercapacitor using MXene-NiCo2S4 as a positive electrode and active carbon as a negative electrode,exhibited an energy density of 27.24 Wh kg 1 at 0.48 kW kg 1 of power density.
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Mansour S. Farhan,Abdul Razak Bushroa,Erfan Zalnezhad,Ahmed Aly Diaa Sarhan 한국정밀공학회 2013 International Journal of Precision Engineering and Vol. No.
Indium-tin oxide (ITO) films have been traditionally deposited at elevated substrate temperature of 400oC to achieve low resistivity and high transmission. In some cases, films deposited at low substrate temperatures can be annealed at higher temperature to achieve lower resistivity. In this paper, thin films of ITO with various oxygen flow rates are prepared by ion-assisted electron beam evaporation at room temperature. Electrical, optical and structural properties of ITO thin films have been investigated with the function of oxygen flow rate, rate of deposition and layer thickness. Low resistivity of 7.5 × 10-4Ω-cm, high optical transmittance of 85% at wavelength 550 nm, optical band-gap of 4.2 eV and crystalline ITO films can be achieved at room temperature almost one order smaller than that prepared by other method.
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Shamshirband, Shahaboddin,Mohammadi, Kasra,Khorasanizadeh, Hossein,Yee, Por Lip,Lee, Malrey,Petković,, Dalibor,Zalnezhad, Erfan Elsevier 2016 RENEWABLE & SUSTAINABLE ENERGY REVIEWS Vol.56 No.-
<P><B>Abstract</B></P> <P>Diffuse solar radiation is a fundamental parameter highly required in several solar energy applications. Despite its significance, diffuse solar radiation is not measured in many locations around the world due to technical and fiscal limitations. On this account, determining the amount of diffuse radiation alternatively based upon precise and reliable estimating methods is indeed essential. In this paper, a coupled model is developed for estimating daily horizontal diffuse solar radiation by integrating the support vector machine (SVM) with wavelet transform (WT) algorithm. To test the validity of the coupled SVM–WT method, daily measured global and diffuse solar radiation data sets for city of Kerman situated in a sunny part of Iran are utilized. For the developed SVM–WT model, diffuse fraction (cloudiness index) is correlated with clearness index as the only input parameter. The suitability of SVM–WT is evaluated against radial basis function SVM (SVM–RBF), artificial neural network (ANN) and a 3rd degree empirical model established for this study. It is found that the estimated diffuse solar radiation values by the SVM–WT model are in favourable agreements with measured data. According to the conducted statistical analysis, the obtained mean absolute bias error, root mean square error and correlation coefficient are 0.5757MJ/m<SUP>2</SUP>, 0.6940MJ/m<SUP>2</SUP> and 0.9631, respectively. While for the SVM–RBF ranked next the attained values are 1.0877MJ/m<SUP>2</SUP>, 1.2583MJ/m<SUP>2</SUP> and 0.8599, respectively. In fact, the study results indicate that SVM–WT is an efficient method which enjoys much higher precision than other models, especially the 3rd degree empirical model.</P>
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