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Thermospheric neutral wind studies over the equatorial region:A review

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Earth and Planetary Physics 2025年第1期9卷 81-100页

作者： Siti Syazwani Nasuha Idahwati Sarudin Nurul Shazana abdul Hamid Ahmad Fairuz Omar School of Physics Universiti Sains Malaysia11800 USMPulau PinangMalaysia Department of Applied Physics Faculty of Science and TechnologyUniversiti Kebangsaan Malaysia43600 UKM BangiSelangorMalaysia Space Science Centre(ANGKASA) Institute of Climate ChangesUniversiti Kebangsaan Malaysia43600 UKM BangiSelangorMalaysia

Thermospheric neutral winds(TNWs)refer to the neutral gases in the thermosphere circulating as tides,which play a crucial role in the dynamics of the thermosphere-ionosphere system(TIS).Global geospace neutral winds,particularly over the magnetic equator,have been a subject of study for several ***,despite the known importance of neutral winds,a comprehensive understanding and characterization of the winds is still *** ground-based and satellite missions have provided valuable information on the contribution of neutral winds to the global atmospheric ***,efforts in the global monitoring of neutral winds are still lacking,and the drivers behind the behavior of TNWs as well as their influence on the TIS remain *** address these knowledge gaps in the global circulation of TNWs,it is crucial to develop a deep understanding of the neutral wind characteristics over different *** low-latitude equatorial region in particular has been observed to exert complex influences on TNWs because of the unique effects of the Earth’s magnetic field at the dip *** neutral winds over this region will provide valuable insights into the unique dynamics and processes that occur in this region,thereby enhancing our understanding of their role in the overall dynamics of the ***,through empirical observations,an improved ability to accurately model and predict the behavior of this region can be *** review article addresses challenges in understanding equatorial winds by reviewing historical measurements,current missions,and the interactions of ionospheric and thermospheric phenomena,emphasizing the need for comprehensive measurements to improve global atmospheric dynamics and weather forecasting.

关键词： thermospheric neutral wind thermosphere-ionosphere system dip equator equatorial region

Antioxidant and lipoxygenase inhibitory properties of a novel flavonoid from Pistacia chinensis Bunge and its molecular docking analysis

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Traditional Medicine Research 2025年第2期10卷 30-36页

作者： Abdur Rauf Zuneera Akram Naveed Muhammad Najla AlMasoud Taghrid Saad Alomar Saima Naz abdul Wadood Chandni Hayat Marcello Iriti Department of Chemistry University of SwabiAmbar 23561Pakistan Department of Pharmacology Faculty of Pharmaceutical SciencesBaqai Medical UniversityKarachi 74600Pakistan Department of Pharmacy Abdul Wali Khan University MardanMardan 23200Pakistan Department of Chemistry College of SciencePrincess Nourah bint Abdulrahman UniversityRiyadh 11671Saudi Arabia Department of Biotechnology BKUC-Bacha Khan University CharsaddaCharsadda 24620Pakistan Department of Biochemistry Abdul Wali Khan University MardanMardan 23200Pakistan Department of Biomedical Surgical and Dental SciencesUniversity of MilanMilan 20129Italy National Interuniversity Consortium of Materials Science and Technology(INSTM) Firenze 50121Italy

Background:Pistacia chinensis Bunge has been traditionally used to manage various conditions,including asthma,pain,inflammation,hepatoprotection,and *** study was conducted to investigate the antioxidant and anti-lipoxygenase(LOX)properties of the isolated compound 2-(3,4-dihydroxyphenyl)-5,7-dihydroxy-4H-chromen-4-one from Pistacia ***:LOX assay and antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl(DPPH)assay were *** docking studies were conducted using a molecular operating ***:The LOX assay revealed significant inhibitory effects at 0.2µM concentration,with an IC50 value of 37.80µ*** antioxidant effect demonstrated dose-dependency across 5 to 100µg/mL concentrations,reaching 93.09%at 100µg/mL,comparable to ascorbic acid’s 95.43%*** docking studies highlighted strong interactions with the lipoxygenase enzyme,presenting an excellent docking score of-10.98 kcal/***:These findings provide valuable insights into Pistacia chinensis’chemical components and biological effects,reinforcing its traditional medicinal applications.

关键词： Pistacia chinensis Bunge antioxidant DPPH assay antilipoxygenase docking analysis

Histopathological studies and oxidative stress of synthesized silver nanoparticles in Mozambique tilapia (Oreochromis mossambicus)

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Journal of Environmental Sciences 2012年第6期24卷 1091-1098页

作者： Rajakumar Govindasamy abdul abdul Rahuman Unit of Nanotechnology and Bioactive Natural Products Post Graduate and Research Department of ZoologyC.Abdul Hakeem CollegeMelvisharam-632509Vellore DistrictTamil NaduIndia

To evaluate the potential environmental effects of engineered nano metals,it is important to determine the adverse effects of various nanomaterials on aquatic *** tilapia （Oreochromis mossambicus） were maintained in 10 L glass aquaria,and exposed to a graded series of synthesized silver nanoparticles （Ag-NPs） at 25,50 and 75 mg/L for eight *** LC 50 value was 12.6 mg/*** activities of antioxidant enzymes and the contents of antioxidants were lowered in the gills and liver of fishes treated with AgNPs,which resulted in heavy accumulation of free *** results imply that the balance between the oxidative and antioxidant system in the fish was broken down during Ag-NPs *** principal concern related with the release of nanomaterials and their smaller particle may change the materials transport and potential toxicity to aquatic organisms compared to larger particles.

关键词： silver nanoparticles Oreochromis mossambicus oxidative stress analysis histopathological studies toxic effect

MODELING DAM-BREAK FLOOD OVER NATURAL RIVERS USING DISCONTINUOUS GALERKIN METHOD

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Journal of Hydrodynamics 2012年第4期24卷 467-478页

作者： KHAN abdul A. Glenn Department of Civil Engineering Clemson University

A well-balanced numerical model is presented for two-dimensional, depth-averaged, shallow water flows based on the Discontinuous Galerkin （DG） method. The model is applied to simulate dam-break flood in natural rivers with wet/dry bed and complex topography. To eliminate numerical imbalance, the pressure force and bed slope terms are combined in the shallow water flow equations. For partially wet/dry elements, a treatment of the source term that preserves the well-balanced property is presented. A treatment for modeling flow over initially dry bed is presented. Numerical results show that the time step used is related to the dry bed criterion. The intercell numerical flux in the DG method is computed by the Harten-Lax-van Contact （HLLC） approximate Riemann solver. A two-dimensional slope limiting procedure is employed to prevent spurious oscillation. The robustness and accuracy of the model are demonstrated through several test cases, including dam-break flow in a channel with three bumps, laboratory dam-break tests over a triangular bump and an L-shape bend, dam-break flood in the Paute River, and the Malpasset dam-break case. Numerical results show that the model is robust and accurate to simulate dam-break flood over natural rivers with complex geometry and wet/dry beds.

关键词： Discontinuous Galerkin (DG) method shallow water flows dam-break flood well-balanced scheme

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

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

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

Systematic Geometric Error Modeling for Workspace Volumetric Calibration of a 5-axis Turbine Blade Grinding Machine

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Chinese Journal of Aeronautics 2010年第5期23卷 604-615页

作者： abdul Wahid Khan School of Mechanical Engineering and Automation Beijing University of Aeronautics and Astronautics

A systematic geometric model has been presented for calibration of a newly designed 5-axis turbine blade grinding machine. This machine is designed to serve a specific purpose to attain high accuracy and high efficiency grinding of turbine blades by eliminating the hand grinding process. Although its topology is RPPPR （P： prismatic; R： rotary）, its design is quite distinct from the competitive machine tools. As error quantification is the only way to investigate, maintain and improve its accuracy, calibra- tion is recommended for its performance assessment and acceptance testing. Systematic geometric error modeling technique is implemented and 52 position dependent and position independent errors are identified while considering the machine as five rigid bodies by eliminating the set-up errors of workpiece and cutting tool. 39 of them are found to have influential errors and are accommodated for finding the resultant effect between the cutting tool and the workpiece in workspace volume. Rigid body kinematics techniques and homogenous transformation matrices are used for error synthesis.

关键词： 5-axis machine tools calibration modeling geometric errors kinematics homogenous transformation matrices

Integrated ozone–photo–Fenton process for the removal of pollutant from industrial wastewater

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Chinese Journal of Chemical Engineering 2017年第4期25卷 516-522页

作者： P.Asaithambi Baharak Sajjadi abdul Raman abdul Aziz Department of Chemical Engineering Faculty of EngineeringUniversity of Malaya50603Malaysia

The use of hybrid advanced oxidation processes(AOPs) for the removal of pollutants from industrial effluents has been extensively studied in recent literature. The aim of this study is to compare the performance of the photo,Fenton, photo-Fenton and ozone–photo–Fenton processes in terms of color removal and chemical oxygen demand(COD) removal of distillery industrial effluent together with the associated electrical energy per order. It was observed from the experimental results that the O_3/UV/Fe^(2 +)/H_2O_2 process yielded a 100% color and95.50% COD removals with electrical energy per order of 0.015 k W·h·m^(-3) compared to all other combinations of the AOPs. The effects of various operating parameters such as H_2O_2 and Fe^(2+) concentration, effluent pH, COD concentration and UV power on the removal of color, COD and electrical energy per order for the ozone–photo–Fenton process was critically studied and reported. The color and COD removals were analyzed using a UV/Vis spectrometer and closed reflux method.

关键词： Fenton photo ozone wastewater pollutant effluent AOPs hydroxyl inorganic irradiation