http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
A. Hafizi,A. AHMADPOUR,M. Koolivand-Salooki,M.M. Heravi,F.F. Bamoharram 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.6
Design of experiments (DOE) and artificial neural networks (ANNs) were successfully applied for studying the operating parameters of benzene alkylation with 1-decene over H14[NaP5W30O110]/SiO2catalyst. In this reaction catalyst loading, catalyst weight percent and benzene to 1-decene molar ratio (Bz/C10) were chosen as independent variables in experimental design. Prediction of 1-decene conversion and 2-phenyldecane selectivity was performed applying response surface method (RSM) and ANN models. Final selected multi-layer (3-6-2-2) ANN model resulted a coefficient of determination (R2)of 0.95 for 1-decene conversion and 0.99 for 2-phenyldecane selectivity, while the R2 of RSM was 0.93and 0.92 for these two parameters.
Mohd Hafizi Ahmad,Nouruddeen Bashir,Hussein Ahmad,Mohamed Afendi Mohamed Piah,Zulkurnain Abdul-Malek,Fadhilah Yusof 대한전기학회 2013 Journal of Electrical Engineering & Technology Vol.8 No.4
This paper presents a statistical approach to analyze electrical tree inception voltage, electrical tree breakdown voltage and tree breakdown time of unsaturated polyester resin subjected to AC voltage. The aim of this work was to show that Weibull and lognormal distribution may not be the most suitable distributions for analysis of electrical treeing data. In this paper, an investigation of statistical distributions of electrical tree inception voltage, electrical tree breakdown voltage and breakdown time data was performed on 108 leaf-like specimen samples. Revelations from the test results showed that Johnson SB distribution is the best fit for electrical tree inception voltage and tree breakdown time data while electrical tree breakdown voltage data is best suited with Wakeby distribution. The fitting step was performed by means of Anderson-Darling (AD) Goodness-of-fit test (GOF). Based on the fitting results of tree inception voltage, tree breakdown time and tree breakdown voltage data, Johnson SB and Wakeby exhibit the lowest error value respectively compared to Weibull and lognormal.
Ahmad, Mohd Hafizi,Bashir, Nouruddeen,Ahmad, Hussein,Piah, Mohamed Afendi Mohamed,Abdul-Malek, Zulkurnain,Yusof, Fadhilah The Korean Institute of Electrical Engineers 2013 Journal of Electrical Engineering & Technology Vol.8 No.4
This paper presents a statistical approach to analyze electrical tree inception voltage, electrical tree breakdown voltage and tree breakdown time of unsaturated polyester resin subjected to AC voltage. The aim of this work was to show that Weibull and lognormal distribution may not be the most suitable distributions for analysis of electrical treeing data. In this paper, an investigation of statistical distributions of electrical tree inception voltage, electrical tree breakdown voltage and breakdown time data was performed on 108 leaf-like specimen samples. Revelations from the test results showed that Johnson SB distribution is the best fit for electrical tree inception voltage and tree breakdown time data while electrical tree breakdown voltage data is best suited with Wakeby distribution. The fitting step was performed by means of Anderson-Darling (AD) Goodness-of-fit test (GOF). Based on the fitting results of tree inception voltage, tree breakdown time and tree breakdown voltage data, Johnson SB and Wakeby exhibit the lowest error value respectively compared to Weibull and lognormal.
Partial Discharge Characteristics in LLDPE-Natural Rubber Blends
Aulia,Mohd Hafizi Ahmad,Zulkurnain Abdul-Malek,Yanuar Z. Arief,Kwan Yiew Lau,Novizon 대한전기학회 2016 Journal of Electrical Engineering & Technology Vol.11 No.3
Partial discharges (PD) lead to the degradation of high voltage cables and accessories. PD activities occur due to the existence of impurities, voids, contaminants, defects and protrusions during the manufacture and installation of power cables. Commonly, insulation failures occur at cable joints and terminations, caused by inhomogeneous electric field distributions. In this work, a blend of natural rubber (NR) and linear low density polyethylene (LLDPE) was investigated, and the optimal formulation of the blend that could resist PD was discussed. The experiments were conducted under a constant high voltage stress test of 6.5 kV AC and the magnitude of partial discharge activities was recorded using the CIGRE method II. Pattern analysis of PD signals was performed along with the interpretation of morphological changes. The results showed that the addition of 10 wt% of NR and 5 wt% of Alumina Trihydrate (ATH) provided promising results in resisting PD activities. However, as the NR content increased, more micropores existed, thus resulting in increased PD activities within the samples.
Malvindran RAVIE,Mohd Hafizi SAID,Noorul Shaiful Fitri ABDUL RAHMAN,Syed Faizal Shah SYED JOHARI SHAH 국제이네비해양경제학회 2017 International Journal of e-Navigation and Maritime Vol.8 No.1
Recently, the migration of refugees has been drastically increasing and became a global issue which indirectly affects the shipmasters, authorities and shipowners during rescue operations. The objective of this paper is to study the challenges or difficulties in rescuing refugees at sea from the perspectives of shipmasters, authorities and shipowners in Malaysia. In this study, the key challenges faced by these three groups of individuals are collected and classified based on the primary data reviewed. The interview sessions were conducted with selected expertise and the data collected are analyzed based on the Analytical Hierarchy Process (AHP) or precisely the pair-wise comparison methods. Through the calculations, the challenges are ranked from the most important challenges to the least important challenges. Furthermore, the data is analyzed by using expert judgments focusing on the relatively most important challenges faced by the three groups of individuals. Finally, the most important challenge faced by shipmasters is the safety of ships and crews, while for authorities, the most important challenge faced is delays in the initiation of rescue operations. For ship-owners, the most important challenge faced is time sensitive cargo loss. Ultimately, two suggestions have been proposed to encounter the most important challenge faced by these groups.
Induced nonlocal electric wave propagation of boron nitride nanotubes
A. Ghorbanpour Arani,A. Hafizi Bidgoli,A. Karamali Ravandi,M. A. Roudbari,S. Amir,M. B. Azizkhani 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.10
Axial displacement and electric wave propagation of single-walled Boron-Nitride nanotubes (SWBNNTs) induced by alternating current (AC) are investigated in this study. A single- walled zigzag structure BNNT is modeled based on nonlocal piezoelasticity theory and Euler-Bernoulli beam (EBB). Equations correspond to lateral displacement have been obtained. Using Hamilton’s principle and considering charge equation for coupling of electrical and mechanical fields, the higher order of governing equations are derived. Analytical solution is applied to solve governing equations. Also the axial and lateral displacement of a SWBNNT and electric potential induced by AC through it are presented. The detailed parametric study is conducted, focusing on the remarkable effects of the half wave number on the behavior of the SWBNNT. The results indicate applying alternating field, leads to propagation of axial displacement along the SWBNNT. Also the result of this study can be useful to design and manufacture of smart micro/nano-electro-mechanical systems in advanced biomechanics applications by controlling axial and lateral displacements.
Aulia, Aulia,Ahmad, Mohd Hafizi,Abdul-Malek, Zulkurnain,Arief, Yanuar Z.,Lau, KwanYiew,Novizon, Novizon The Korean Institute of Electrical Engineers 2016 Journal of Electrical Engineering & Technology Vol.11 No.3
Partial discharges (PD) lead to the degradation of high voltage cables and accessories. PD activities occur due to the existence of impurities, voids, contaminants, defects and protrusions during the manufacture and installation of power cables. Commonly, insulation failures occur at cable joints and terminations, caused by inhomogeneous electric field distributions. In this work, a blend of natural rubber (NR) and linear low density polyethylene (LLDPE) was investigated, and the optimal formulation of the blend that could resist PD was discussed. The experiments were conducted under a constant high voltage stress test of 6.5 kV AC and the magnitude of partial discharge activities was recorded using the CIGRE method II. Pattern analysis of PD signals was performed along with the interpretation of morphological changes. The results showed that the addition of 10 wt% of NR and 5 wt% of Alumina Trihydrate (ATH) provided promising results in resisting PD activities. However, as the NR content increased, more micropores existed, thus resulting in increased PD activities within the samples.
Maryam Rajabzadeh,Reza Khalifeh,Hossein Eshghi,Ali Hafizi 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.89 No.-
A new nanoreactor type structure composed of hollow mesoporous silica spheres and CuO nanoparticlesloaded inside the interior cavity of spheres has been designed and successfully prepared. The synthesismethod is proceed in a four step procedure by using carbon spheres as the hard template together with acoating of tetraethyl orthosilicate (TEOS) and cetyltrimethyl ammonium bromide (CTAB) mixture. Theobtained nanoreactors were characterized with FE-SEM, elemental mapping, TEM, XRD, BET, ICP and TPRanalysis. The CO2 fixation reaction is applied to evaluate the catalytic performance of the synthesizedCuO@SiO2 multi-yolk@shell catalyst. This catalyst exhibits superior activity in CO2 fixation reactions with96% yield in 4 h at low pressure. The catalyst demonstrates superb mechanical stability, high activity andis recovered for at least six times without loss of activity in CO2 fixation reaction, showing that this type ofnanoreactor could be applied as a promising material in advanced catalysis applications.