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Journal of Central South University 2020年第11期27卷 3175-3187页

作者： Mustafa Khaleel IBRAHIM Safaa Najah SAUD Esah HAMZAH engku mohamad nazim Faculty of Computer Engineering University of Imam Jafar Sadeq Maysan BranchMaysan 62012Iraq Faculty of Information Sciences and Engineering Management&Science University40100 Shah AlamSelangorMalaysia Faculty of Mechanical Engineering Universiti Teknologi Malaysia81310 UTM Johor BahruJohorMalaysia

In the present study,the thermal,mechanical,and biological properties of xAg/Ti-30Ta(x=0,0.41,0.82 and 2.48 at%)shape memory alloys(SMAs)were *** study was conducted using optical and scanning electron microscopy(SEM),X-ray diffractometry(XRD),compression test,and shape memory *** xAg/Ti-Ta was made using a powder metallurgy technique and microwave-sintering *** results revealed that the addition of Ag has a significant effect on the pore size and shape,whereas the smallest pore size of 11μm was found with the addition of 0.41 at%along with a relative density of 72%.The fracture stress and strain increased with the addition of Ag,reaching the minimum values around 0.41 at%***,this composition showed the maximum stress and strain at fracture ***,0.82 Ag/Ti-Ta shows more excellent corrosion resistance and biocompatibility than other percentages,obtaining almost the same behaviour of the pure Ti and Ti-6Al-4V alloys,which can be recommended for their promising and potential response for biomaterial applications.

关键词： porous xAg/Ti-Ta shape memory alloys(SMAs) microwave sintering process microstructure characteristics mechanical properties and corrosion behavior bioactivity

The resistance switching performance of the memristor improved effectively by inserting carbon quantum dots(CQDs)for digital information processing

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Nano Research 2024年第9期17卷 8438-8446页

作者： Tianqi Yu Jie Li Wei Lei Suhaidi Shafe Mohd nazim Mohtar Nattha Jindapetch Paphavee van Dommelen Zhiwei Zhao Joint International Research Laboratory of Information Display and Visualization School of Electronic Science and EngineeringSoutheast UniversityNanjing 210096China Institute of Nanoscience and Nanotechnology University Putra MalaysiaSerdangSelangor 43400Malaysia Department of Electrical Engineering Faculty of EngineeringPrince of Songkla UniversityHat YaiSongkhla 90112Thailand Division of Physical Science Faculty of SciencePrince of Songkla UniversityHat Yai Campus 15 KarnjanavanichHat YaiSongkhla 90110Thailand

As an emerging information device that adapts to development of the big data era,memristor has attracted much attention due to its advantage in processing massive ***,the nucleation and growth of conductive filaments often exhibit randomness and instability,which undoubtedly leads to a wide and discrete range of switching parameters,damaging the electrical performance of *** this work,a strategy of inserting carbon quantum dots(CQDs)into graphene oxide(GO)resistance layer is utilized to improve the stability of the switching parameters and the reliability of the device is *** with GO-based devices,GO/CQDs/GO-based devices exhibit a more stable resistance switching curve,low power,lower and more concentrated threshold voltage parameters with lower variation coefficient,faster switching speed,and more stable retention and *** cause-inducing performance improvement may be attributed to the local electric field generated by CQDs in resistance switching that effectively guides the formation and rupture of conductive filaments,which optimizes the effective migration distance of Ag^(+),thereby improving the uniformity of resistance ***,a convolutional neural network model is constructed to identify the CIFAR-10 data set,showing the high recognition accuracy of online and offline *** cross-kernel structure is used to further implement convolutional image processing through multiplication and accumulation *** work provides a solution to improve the performance of memristors,which can contribute to developing digital information processing.

关键词： carbon quantum dots memristor uniformity convolutional neural network convolutional image processing

A Survey of VASNET Framework to Provide Infrastructure-Less Green IoTs Communications for Data Dissemination in Search and Rescue Operations

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Journal of Electronic Science and Technology 2016年第3期14卷 220-228页

作者： mohamad nazim Jambli Adnan Shahid Khan Sia Chiu Shoon the Faculty of Computer Science and Information Technology Universiti Malaysia Sarawak94300 Kota SamarahanMalaysia

implementation of wireless technologies based on the vehicular ad hoc sensor network （VASNET） may provide support for the search and rescue （SAR） team to operate effectively in natural disaster events, such as landslide, earthquake, flooding, and tsunami. The operations of SAR team are very challenging in such events due to the possible damages of the existing telecommunication infrastructures. The existing deployment of the cellular communications infrastructure may be partially or completely destroyed after the occurrence of these natural disasters. Thus, the current VASNET infrastructure must be able to support the infrastructure-less network by integrating other green wireless technologies that can benefit the SAR team, which can indirectly save more human lives and reduce the number of casualties. Therefore, the integration of green Internet of things （loT） and VASNET is proposed to form a heterogeneous framework for data dissemination in SAR operations. In addition, this paper also discusses the existing lot framework in disaster scenarios with future research direction for IoT using on any aspect, especially related to the natural disaster scenarios.

关键词： Framework green Internet of things (loT) SAR operations vehicular ad hoc sensor network (VASNET).

Ultra-high-performance liquid chromatography-quadrupole time-of-flight-mass spectrometry-characterized extract of Aerides odorata Lour alleviates paracetamol-induced hepatotoxicity in animal model evidenced by biochemical, molecular, and computational studies

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ANIMAL MODELS AND EXPERIMENTAL MEDICINE 2024年第4期7卷 497-522页

作者： Abu Ahmed, A. M. Rahman, Md. Atiar Sharmen, Farjana Reza, A. S. M. Ali Islam, Md. Shahidul Rashid, Md. Mamunur Rafi, Md. Khalid Juhani Siddiqui, Tanvir Ahmed Ezaj, Md. Muzahid Ahmed Saha, Srabonti Uddin, Md. nazim Alelwani, Walla Univ Chittagong Dept Genet Engn & Biotechnol Chittagong Bangladesh Univ Chittagong Dept Biochem & Mol Biol Chittagong 4331 Bangladesh Int Islami Univ Chittagong Dept Pharm Chittagong Bangladesh Bangladesh Council Sci & Ind Res Inst Food Sci & Technol Dhaka Bangladesh Univ Jeddah Coll Sci Dept Biochem Jeddah Saudi Arabia

Background: Many kinds of orchids have significant health benefits although adequate research on their biological functions is yet to be carried out. This study investigated the paracetamol-induced liver damage-protecting effect of epiphytic Aerides odorata methanol extract (AODE). Methods: The protective effects of AODE were studied by analyzing its effect on liver function parameters, messenger RNA (mRNA) expression, and tissue histopathological architecture. The results were confirmed by ligand-receptor interaction of molecular docking and multitarget interaction of network pharmacological analyses. Results: AODE significantly (p < 0.05) minimized the dose-dependent increase in acid phosphatase, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, gamma-glutamyl transferase, lactate dehydrogenase, and total bilirubin compared to the reference drug silymarin. Malondialdehyde level decreased, and the antioxidant genes catalase (CAT), superoxide dismutase (SOD), beta-actin, paraoxonase-1 (PON1), and phosphofructokinase-1 (PFK-1) were upregulated in AODE-treated paracetamol-intoxicated rats. A total of 376 compounds comprising phenols and flavonoids were identified using ultra-high-performance liquid chromatography-quadrupole time-of-flight-mass spectrometry (UPLC-qTOF-MS). The online toxicity assessment using SwissADME and admetSAR exhibited drug-like, nontoxic, and potential pharmacological properties. Additionally, in silico analysis showed that isoacteoside, one of the identified compounds, exhibited the best docking score (-11.42) with the liver protein human pituitary adenylate cyclase-1 (Protein Data Bank ID: 3N94). Furthermore, network pharmacology analysis identified the top 10 hub genes, namely AKT1 (protein kinase B), CTNNB1 (catenin beta-1), SRC (proto-oncogene c-Src), TNF (tumor necrosis factor), EGFR (epidermal growth factor receptor), HSP90AA1 (heat shock protein 90 alpha), MAPK3 (mitogen-activated protein kinase 3), STAT3 (signa

关键词： Aerides odorata animal model mRNA expression PCM-induced hepatotoxicity UPLC-qTOF-MS MESSENGER-RNA EXPRESSION HEPATOPROTECTIVE ACTIVITY ANTIOXIDANT ACTIVITIES OXIDATIVE STRESS REDUCTASE TOXICITY GENES MAPK3 CELL STEM

Thermal fluid-structure interaction and coupled thermal-stress analysis in a cable stayed bridge exposed to fire

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Frontiers of Structural and Civil Engineering 2018年第4期12卷 609-628页

作者： nazim Abdul NARIMAN Institute of Structural Mechanics Faculty of Civil EngineeringBauhaus Universitat WeimarMarienstrasse 1599423WeimarGermany

In this paper, thermal fluid structure-interaction (TFSI) and coupled thermal-stress analysis are utilized to identify the effects of transient and steady-state heat-transfer on the vortex induced vibration and fatigue of a segmental bridge deck due to fire incidents. Numerical simulations of TFSI models of the deck are dedicated to calculate the lift and drag forces in addition to determining the lock-in regions once using fluid-structure interaction (FSI) models and another using TFSI models. Vorticity and thermal convection fields of three fire scenarios are simulated and analyzed. Simiu and Scanlan benchmark is used to validate the TFSI models, where a good agreement was manifested between the two results. Extended finite element method (XFEM) is adopted to create 3D models of the cable stayed bridge to simulate the fatigue of the deck considering three fire scenarios. Choi and Shin benchmark is used to validate the damaged models of the deck in which a good coincide was seen between them. The results revealed that TFSI models and coupled thermal-stress models are significant in detecting earlier vortex induced vibration and lock-in regions in addition to predicting damages and fatigue of the deck due to fire incidents.

关键词： fire scenario transient heat transfer TFSI model coupled thermal-stress XFEM

A novel structural modification to eliminate the early coupling between bending and torsional mode shapes in a cable stayed bridge

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Frontiers of Structural and Civil Engineering 2017年第2期11卷 131-142页

作者： nazim Abdul NARIMAN Institute of Structural Mechanics Faculty of Civil Engineering Bauhaus University Weimar Weimar 99423 Germany

In this paper, a novel structural modification approach has been adopted to eliminate the early coupling between the bending and torsional mode shapes of vibrations for a cable stayed bridge model generated using ABAQUS software. Two lateral steel beams are added to the middle span of the structure. Frequency analysis is dedicated to obtain the natural frequencies of the first eight mode shapes of vibrations before and after the structural modification approach. Numerical simulations of wind excitations are conducted for the 3D model of the cable stayed bridge with duration of 30 s supporting on real data of a strong wind from the literature. Both vertical and torsional displacements are calculated at the mid span of the deck to analyze both the bending and the torsional stiffness of the system before and after the structural modification. The results of the frequency analysis after applying lateral steel beams declared a safer structure against vertical and torsional vibrations and rarely expected flutter wind speed. Furthermore, the coupling between the vertical and torsional mode shapes has been removed to larger natural frequencies magnitudes with a high factor of safety. The novel structural approach manifested great efficiency in increasing vertical and torsional stiffness of the structure.

关键词： aeroelastic instability structural damping flutter wind speed bending stiffness torsional stiffness

Influence of fluid-structure interaction on vortex induced vibration and lock-in phenomena in long span bridges

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Frontiers of Structural and Civil Engineering 2016年第4期10卷 363-384页

作者： nazim Abdui NARIMAN Institute of Structural Mechanics Faculty of Civil Engineering Bauhaus University Weimar Weimar 99423 Germany

In this paper, deck models of a cable stayed bridge are generated in ABAQUS-finite element program once using only CFD model （one-way fluid-structure interaction） and another by using both the CFD model and the CSD model together （two-way fluid-structure interaction） in a co-simulation. Shedding frequencies for the associated wind velocities in the lock-in region are calculated in both approaches. The results are validated with Simiu and Scanlan results. The lift and drag coefficients are determined for the two approaches and the latter results are validated with the flat plate theory results by Munson and coauthors. A decrease in the critical wind velocity and the shedding frequencies considering two-way approach was determined compared to those obtained in the one-way approach. The results of the lift and drag forces in the two-way approach showed appreciable decrease in their values. It was concluded that the two-way approach predicts earlier vortex induced vibration for lower critical wind velocities and lock-in phenomena will appear at lower natural frequencies of the long span bridges. This helps the designers to efficiently plan and consider for the design and safety of the long span bridge against this type of vibration.

关键词： vortex-induced vibration fluid-structure interaction Strouhal number lock-in kinetic energy

DEFPOS Hα observations of the W80 Complex

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Research in Astronomy and Astrophysics 2013年第5期13卷 547-556页

作者： nazim Aksaker Vocational School of Technical Sciences University of C ukurova Research and Application of Space Sciences and Solar Energy Center (UZAYMER) University of Cukurova

We present Hα emission line measurements of the W80 nebula complex. A total of 26 regions have been observed inside the nebula with the Dual Etalon Fabry- Perot Optical Spectrometer system at the f/48 Coud6 focus of the 150 cm RTT150 telescope located at TUBITAK National Observatory in Antalya, Turkey. The inten- sities, local standard of rest velocities, heliocentric radial velocities and linewidths for full width at half maximum of the Hα emission lines have been determined from these observations. They lie in the range of 259 to 1159 Rayleigh （R; 1R = 106/47r pho- tons cm-2 sr-1 S-1 = 2.41 × 10-7 erg cm-2 sr-1 S-1 at Ha）, 4 to 12 km s-1, -3 to -11 km s-1 and 44 to 55 km s-i, respectively. The radial velocity measurements show that there are several maxima and minima inside W80. The new results confirm findings in the literature that the complex seems to be rather uniform in terms of radial velocity and no turbulent motion is seen inside the complex. The average value of the calculated emission measure for the region is 3.1 pc cm-6.

关键词： instrumentation: interferometers -- ISM: H II regions -- techniques:radial velocities -- techniques: interferometric

Control efficiency optimization and Sobol＇s sensitivity indices of MTMDs design parameters for buffeting and flutter vibrations in a cable stayed bridge

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Frontiers of Structural and Civil Engineering 2017年第1期11卷 66-89页

作者： nazim Abdul NARIMAN Institute of Structural Mechanics School of Civil Engineering Bauhaus University Weimar Weimar 99423 Germany

This paper studies optimization of three design parameters （mass ratio, frequency ratio and damping ratio） of multiple tuned mass dampers MTMDs that are applied in a cable stayed bridge excited by a strong wind using minimax optimization technique. ABAQUS finite element program is utilized to run numerical simulations with the support of MATLAB codes and Fast Fourier Transform FFT technique. The optimum values of these three parameters are validated with two benchmarks from the literature, first with Wang and coauthors and then with Lin and coauthors. The validation procedure detected a good agreement between the results. Box-Behnken experimental method is dedicated to formulate the surrogate models to represent the control efficiency of the vertical and torsional vibrations. Sobol＇s sensitivity indices are calculated for the design parameters in addition to their interaction orders. The optimization results revealed better performance of the MTMDs in controlling the vertical and the torsional vibrations for higher mode shapes. Furthermore, the calculated rational effects of each design parameter facilitate to increase the control efficiency of the MTMDs in conjunction with the support of the surrogate models.

关键词： MTMDs power spectral density fast Fourier transform minimax optimization technique Sobol's sensitivityindices Box-Behnken method

Uncertainty quantification of stability and damage detection parameters of coupled hydrodynamic-ground motion in concrete gravity dams

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Frontiers of Structural and Civil Engineering 2019年第2期13卷 303-323页

作者： nazim Abdul NARIMAN Tom LAHMER Pevman KARAMPOUR Institute of Structural Mechanics Faculty of Civil EngineeringBauh aus Universitat Weimar99423 WeimarGermany Department of Mechanical Engineering Faculty of EngineeringArak UniversityArak 38156-8-8849Iran

In this paper, models of the global system of the Koyna dam have been created using ABAQUS software considering the dam-reservoir-fbundation interaction. Non coupled models and the coupled models were compared regarding the horizontal displacement of the dam crest and the differential settlement of the dam base in clay foundation. Meta models were constructed and uncertainty quantification process was adopted by the support of Sobol's sensitivity in dices considering five un certain parameters by exploiting Box-Behnken experimental method. The non coupled models results determined overestimated predicted stability and damage detection in the dam. The rational effects of the reservoir height were very sensitive in the variation of the horizontal displacement of the dam crest with a small interaction effect with the beta viscous damping coefficient of the clay fbundation. The modulus of elasticity of the clay foundation was the decisive parameter regarding the variation of the differential settlement of the dam base. The XFEM approach has been used for damage detection in relation with both minimum and maximum values of each uncertain parameter. Finally the effects of clay and rock foundations were determined regarding the resistance against the propagation of cracks in the dam, where the rock fbundation was the best.

关键词： massed foundation hydrodynamic pressure Box-Behnken method meta model Sobol's sensitivity indices