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Study on the flow structure around discontinued vertically layered vegetation in an open channel

Journal of Hydrodynamics 2020年第3期32卷 454-467页

作者： naveed Anjum Norio Tanakia Graduate School of Science and Engineering Saitama UniversitySaitama-shiJapan International Institute for Resilient Society Saitama UniversitySaitama-shiJapan

The flow structure and geomorphology of rivers are significantly affected by vegetation patterns. In the present study, the effect of vegetation in the form of discontinuous and vertically double layered patches particularly on the resulting flow turbulence was examined computationally in an open channel. A k-ɛ model was implemented in this research work which was developed using 3-d numerical code FLUENT (ANSYS). After the validation process of numerical model, the impact of discontinuous layered vegetation patches on the flow turbulence was investigated against varying vegetation density and patch length. The mean stream-wise velocities at specified positions showed larger spatial fluctuations directly upstream and downstream of vegetation elements, whereas sharp inflections in the profiles were witnessed at the top of smaller submerged elements i.e. z/hs= 1 (where z is the flow depth and hs is the smaller vegetation height). The reduction in flow velocity due to tall vegetation structure was more as compared with that of short vegetation. The mean velocity in the patch regions was visibly higher than that in the gap regions. The profiles of turbulent flow properties showed more rise and fall within the patches with a high vegetation density i.e. Ss/d= 4;and St/d= 8 (where Ss/d and St/d are the smaller and taller vegetation spacing, while d is the vegetation diameter) as compared with low vegetation density i.e. Ss/d= 8;and St/d= 16. The turbulent flow structure in the large patch and gap regions was found to be more stable than that in the small patches and gaps;whereas, due to the variation in distribution form of the patch, turbulence is relatively unaffected, and the flow structure variation is low. Turbulence was observed to be large, followed by a saw-tooth distribution within the patches;whereas, low turbulence is observed in the non-vegetation regions. The turbulent intensity acquired maximum of 13% turbulence for dense vegetation arrangement as compared t

关键词： discontinuous and layered vegetation patches open channel flow numerical simulation mean flow velocity turbulence modeling flow characteristics

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Numerical investigation of velocity distribution of turbulent flow through vertically double-layered vegetation

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Water Science and Engineering 2019年第4期12卷 319-329页

作者： naveed Anjum Norio Tanaka Graduate School of Science and Engineering Saitama UniversitySaitama 338-8570Japan International Institute for Resilient Society Saitama UniversitySaitama 338-8570Japan

The velocity structures of flow through vertically double-layered vegetation(VdLV)as well as single-layered rigid vegetation(SLV)were investigated computationally with a three-dimensional(3d)Reynolds stress turbulence model,using the computational fluid dynamics(CFd)code *** detailed velocity distribution was explored with a varying initial Froude number(Fr),with consideration of the steady subcritical flow conditions of an inland *** VdLV flows,the numerical model successfully captured the inflection point in the profiles of mean streamwise velocities in the mixing-layer region around the top of short submerged *** upward and downward movement of flow occurred at the positions located just behind the tall and short vegetation,***,higher streamwise velocities were observed in the upper vegetation layer due to high porosity,with Pr=98%(sparse vegetation,where Pr is the porosity),as compared to those in the lower vegetation layer,which had comparatively low porosity,with Pr=91%(dense vegetation).A rising trend of velocities was found as the flow passed through the vegetation region,followed by a clear sawtooth distribution,as compared to the regions just upstream and downstream of vegetation where the flow was almost *** VdLV flows,a rising trend in the flow resistance was observed with the increase in the initial Froude number,i.e.,Fr?0.67,0.70,and ***,the flow resistance in the case of SLV was relatively very *** numerical results also show the flow structures within the vicinity of short and tall vegetation,which are difficult to attain through experimental measurements.

关键词： Vertically double-layered vegetation Single-layered rigid vegetation Numerical modeling FLUENT Velocity distribution Turbulent flow

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Electro-derived Cu-Cu2O nanocluster from LdH for stable and selective C2 hydrocarbons production from CO2 electrochemical reduction

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Journal of Energy Chemistry 2020年第9期29卷 169-180,I0005页

作者： naveed Altaf Shuyu Liang Liang Huang Qiang Wang College of Environmental Science and Engineering Beijing Forestry UniversityBeijing 100083China

Recently,CO2 conversion by electrochemical tool into value-added chemicals has been considered as one of the most promising strategies to offer sustainable development in energy and *** this contribution,we investigated electro-derived composites from Cu-based layered double hydroxide(LdH)for CO2 electrochemical *** Cu-Cu2O based nanocomposite(HPR-LdH)were derived by using electro-strategy from LdH having the stability up to 20 h and selectivity toward C2H4 with faraday efficiency up to 36%by significantly suppressing CH4 and H2 with respect to bulk Cu foil.A highly negative reduction potential derived catalyst(HPR-LdH)maintained long-term stability for the selective production of ethylene over methane,and a small amount of Cu2O was still observed on the catalyst surface after CO2 reduction reaction(CO2RR).Moreover,such unique strategy for electro-derived composite from LdH having small nanoparticles stacked each other grown on layered structure,would provide new insight to improve durability of O-Cu combination catalysts for C-C coupling products during electrochemical CO2conversion by suppressing *** XRd,SEM,ESR,and XPS analyses confirmed that the long-term ethylene selectivity of HPR-LdH is due to the presence of subsurface *** designed composite catalyst significantly enhances the stability and selectivity,and also decreases the over potential for CO2 *** predict that the new designed LdH 2d-derived composites may attract new insight for transition metal and may open up a new direction for known structural properties of selective catalyst synthesis regarding effective CO2 reduction reaction.

关键词： Electrochemical Electro-derived strategy Layered double hydroxide Ethylene Cu2O nanocomposites

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development of multi-physics numerical simulation model to investigate thermo-mechanical fatigue crack propagation in an autofrettaged gun barrel

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defence Technology（防务技术） 2021年第5期17卷 1579-1591页

作者： naveed Hussain Faisal Qayyum Riffat Asim Pasha Masood Shah department of Mechanical Engineering University of Engineering and TechnologyTaxilaPakistan Institut für Metallformung Technische Universitat BeragakademieFreibergGermany

In this research,a detailed multi-physics study has been carried out by numerically simulating a solid fractured gun barrel for 20 thermo-mechanical *** numerical model is based on thermal effects,mechanical stress fields and fatigue crack ***-plastic material data of modified AISI 4340 at temperatures ranging from 25 to 1200℃and at strain rates of 4,16,32 and 48 s^(-1) was acquired from high-temperature compression *** was used as material property data in the simulation *** boundary conditions applied are kept similar to the working gun barrel during continuous firing.A methodology has been provided to define thermo-mechanically active surface-to-surface type interface between the crack faces for a better approximation of stresses at the crack *** of results from non-autofrettaged and autofrettaged simulation models provide useful information about the evolution of strains and stresses in the barrel at different points under combined thermo-mechanical loading cycles in both *** effect of thermal fatigue under already induced compressive yield due to autofrettage and the progressive degradation of the accumulated stresses due to thermo-mechanical cyclic loads on the internal surface of the gun barrel(mimicking the continuous firing scenario)has been *** between energy release rate at tips of varying crack lengths due to cyclic thermo-mechanical loading in the non-autofrettaged and autofrettaged gun has been carried out.

关键词： Steel Autofrettage Gun barrel Crack propagation Thermo-mechanical fatigue Numerical simulation Residual stress dissipation

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Overgrowth of the indigenous gut microbiome and irritable bowel syndrome

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World Journal of Gastroenterology 2014年第10期20卷 2449-2455页

作者： William Bye naveed Ishaq Terry d Bolin Vic M duncombe Stephen M Riordan Gastrointestinal and Liver Unit Prince of Wales Hospital Randwick 2031 New South Wales Australia Prince of Wales Clinical School Randwick NSW 2031 Australia

Culture-independent molecular techniques have demonstrated that the majority of the gut microbiota is *** of these molecular techniques to more accurately identify the indigenous gut microbiome has moved with great pace over recent years,leading to a substantial increase in understanding of gut microbial communities in both health and a number of disorders,including irritable bowel syndrome(IBS).Use of culture-independent molecular techniques already employed to characterise faecal and,to a lesser extent,colonic mucosal microbial populations in IBS,without reliance on insensitive,traditional microbiological culture techniques,has the potential to more accurately determine microbial composition in the small intestine of patients with this disorder,at least that occurring proximally and within reach of *** data concerning culture-based and culture-independent analyses of the small intestinal microbiome in IBS are considered here.

关键词： Gut microbiome Small intestinal bacterial overgrowth Irritable bowel syndrome

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Self-Interference Elimination by Physical Feedback Channel in CCFd for 3-d Beamforming Communication

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China Communications 2017年第9期14卷 62-71页

作者： naveed Ali Kaimkhani Zhe Chen Fuliang Yin School of Information and Communication Engineering Dalian University of Technology

The 3-d beamforming scheme has elite as evolving interest because of its efficiency to empower assorted techniques such as vertical and horizontal domains and emanation beamforming according to subscriber's provisions. Usually, 3-d beamforming communication is set up on Fdd/Tdd approach those effects on the performance of spectrum and energy efficiency. Co-frequency and CoTime Full duplex(CCFd) is an effective solution to improve the spectrum and energy efficiency by transmitting and receiving simultaneously in frequency and time domain. While, CCFd communication often face the self-interference issue when communication occurs, simultaneously. Consequently, in this paper a self-interference elimination by physical feedback channel in CCFd for 3-d Beamforming communication scheme is proposed to improve the over-all system performance in terms of energy and spectrum efficiency. The simulation and analytical outcomes demonstrated that the proposed system is superior than the traditional one.

关键词： spectrum efficiency energy effi-ciency co-frequency and co-time full duplex self-interference suppression 3-d beamform-ing

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Novel LaFe_(2)O_(4)spinel structure with a large oxygen reduction response towards protonic ceramic fuel cell cathode

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Journal of Rare Earths 2023年第3期41卷 413-421,I0004页

作者： Jinping Wang Yuzheng Lu naveed Mushtaq M.A.K Yousaf Shah Sajid Rauf Peter d.Lund Muhammad Imran Asghar School of Energy and Power Engineering Nanjing Institute of TechnologyNanjing 211167China School of Electronic Engineering Nanjing Xiao Zhuang UniversityNanjing 211171China Jiangsu Provincial Key Laboratory of Solar Energy Science and Technology/Energy Storage Joint Research Center School of Energy and EnvironmentSoutheast UniversityNanjing 210096China College of Electronics and Information Engineering Shenzhen UniversityShenzhen 518000China New Energy Technologies Group Department of Applied PhysicsAalto University School of ScienceP.O.Box.15100FI00076AaltoEspooFinland Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials Faculty of Physics and Electronic ScienceHubei UniversityWuhan 430062China

Highly active and stable electrocatalysts are mandatory for developing high-performance and longlasting fuel *** current study demonstrates a high oxygen reduction reaction(ORR)electrocatalytic activity of a novel spinel-structured LaFe_(2)O_(4)via a self-doping *** LaFe_(2)O_(4)demonstrates excellent ORR activity in a protonic ceramic fuel cell(PCFC)at temperature range of 350-500℃.The high ORR activity of LaFe_(2)O_(4)is mainly attributed to the facile release of oxide and proton ions,and improved synergistic incorporation abilities associated with interplay of multivalent Fe^(3+)/Fe^(2+)and La^(3+)*** LaFe_(2)O_(4)as cathode over proton conducting BaZr_(0.4)Ce_(0.4)Y_(0.2)O_(3)(BZCY)electrolyte,the fuel cell has delivered a high-power density of 806 mW/cm^(2)operating at 500℃.different spectroscopic and calculations methods such as UV-visible,Raman,X-ray photoelectron spectroscopy and density functional theory(dFT)calculations were performed to screen the potential application of LaFe_(2)O_(4)as *** study would help in developing functional cobalt-free ORR electrocatalysts for low temperature-PCFCs(LT-PCFCs)and solid oxide fuel cells(SOFCs)applications.

关键词： LaFe_(2)O_(4)cathode Facile Fe^(3+/2+)ions resale Oxygen reductionreaction(ORR) Excellent electrocatalyst Protonic ceramicfuel cell(PCFC) Rare earths

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Highly Active Interfacial Sites in SFT-SnO_(2) Heterojunction Electrolyte for Enhanced Fuel Cell Performance via Engineered Energy Bands:Envisioned Theoretically and Experimentally

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Energy & Environmental Materials 2024年第3期7卷 384-397页

作者： Sajid Rauf Muhammad Bilal Hanif Faiz Wali Zuhra Tayyab Bin Zhu naveed Mushtaq Yatao Yang Kashif Khan Peter d.Lund Martin Motola Wei Xu College of Electronic and Information Engineering and State Key Laboratory of Radio frequency Heterogeneous Integration Shenzhen UniversityShenzhen 518000China department of Inorganic Chemistry Faculty of Natural SciencesComenius University in BratislavaIlkovicova 684215BratislavaSlovakia College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhen 518060China School of Energy and Environment Southeast UniversityNo.2 Si Pai LouNanjing 210096China School of Materials and Energy University of Electronic Science and Technology of ChinaChengdu 611731China New Energy Technologies Group Department of Applied PhysicsAalto University School of ScienceP.O.Box 15100Fl-00076AaltoEspoo Finland

Extending the ionic conductivity is the pre-requisite of electrolytes in fuel cell technology for high-electrochemical *** this regard,the introduction of semiconductor-oxide materials and the approach of heterostructure formation by modulating energy bands to enhance ionic conduction acting as an electrolyte in fuel ***(n-type;SnO_(2))plays a key role by introducing into p-type SrFe_(0.2)Ti_(0.8)O_(3-δ)(SFT)semiconductor perovskite materials to construct p-n heterojunction for high ionic ***,two different composites of SFT and SnO_(2)are constructed by gluing p-and n-type SFT-SnO_(2),where the optimal composition of SFT-SnO_(2)(6∶4)heterostructure electrolyte-based fuel cell achieved excellent ionic conductivity 0.24 S cm^(-1)with power-output of 1004 mW cm^(-2)and high OCV 1.12 V at a low operational temperature of 500℃.The high power-output and significant ionic conductivity with durable operation of 54 h are accredited to SFT-SnO_(2)heterojunction formation including interfacial conduction assisted by a built-in electric field in fuel cell ***,the fuel conversion efficiency and considerable Faradaic efficiency reveal the compatibility of SFT-SnO_(2)heterostructure electrolyte and ruled-out short-circuiting ***,the first principle calculation provides sufficient information on structure optimization and energy-band structure modulation of SFT-SnO_(2).This strategy will provide new insight into semiconductor-based fuel cell technology to design novel electrolytes.

关键词： high ionic conductivity interfacial conduction modulated energy band structure p-n heterojunction semiconductors

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Superposition of Stationary Wave Fields Via Atom Microscopy

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Communications in Theoretical Physics 2015年第3期63卷 340-346页

作者： Hizbullah Anwar Ali khan naveed Khan Iftikhar ahm.d Bakht Amin Bacha department of Physics University of Malakand Chakdara department of Physics Hazara University

We investigate one-dimensional position microscopy of a three-level atom moving through a stationary wave region under the condition of electromagnetically induced *** precise position information of an atom is observed on the resonance absorption and dispersion distribution spectrum of a weak probe *** and multiple localization peaks are observed in specific directions of the corresponding wave numbers and phase of the standing wave *** strength of space-independent Rabi frequency reduces the position uncertainty in the localized peaks without disturbing the probability of the *** a hot atomic medium the localized probability of an atom is reduced which depends upon the temperature of that *** results provide useful applications in the development of laser cooling,atom nanolithography and Bose-Einstein condensation.

关键词： 1d atom localization superposition of standing waves fields

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Structure-based protein-protein interaction networks and drug design

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Frontiers of Electrical and Electronic Engineering in China 2013年第3期8卷 183-191页

作者： Hammad naveed Jingdong J. Han Chinese Academy of Sciences Key Laboratory of Computational Biology Chinese Academy of Sciences-Max Planck PartnerInstitute for Computational Biology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences Shanghai200031 China

Proteins carry out their functions by interacting with other proteins and small molecules, forming a complex interaction network. In this review, we briefly introduce classical graph theory based protein-protein interaction networks. We also describe the commonly used experimental methods to construct these networks, and the insights that can be gained from these networks. We then discuss the recent transition from graph theory based networks to structure based protein-protein interaction networks and the advantages of the latter over the former, using two networks as examples. We further discuss the usefulness of structure based protein-protein interaction networks for drug discovery, with a special emphasis on drug repositioning.

关键词： protein-protein interaction network structure-based drug design drug reposition

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