检索结果-南通市图书馆

Communications in Computational Physics 2012年第8期12卷 767-788页

作者： ravi kannan CFD Research Corporation 215Wynn DriveHuntsville AL 35805USA

In this paper,the second in a series,we improve the discretization of the higher spatial derivative terms in a spectral volume(SV)*** motivation for the above comes from[***.,46(2),314–328],wherein the authors developed a variant of the LDG(Local Discontinuous Galerkin)flux discretization *** variant(aptly named LDG2),not only displayed higher accuracy than the LDG approach,but also vastly reduced its unsymmetrical *** this paper,we adapt the LDG2 formulation for discretizing third derivative terms.A linear Fourier analysis was performed to compare the dispersion and the dissipation properties of the LDG2 and the LDG *** results of the analysis showed that the LDG2 scheme(i)is stable for 2nd and 3rd orders and(ii)generates smaller dissipation and dispersion errors than the LDG formulation for all the *** 4th order LDG2 scheme is howevermildly unstable:as the real component of the principal eigen value briefly becomes *** order to circumvent the above,a weighted average of the LDG and the LDG2 fluxes was used as the final numerical *** a weight of 1.5%for the LDG(i.e.,98.5%for the LDG2)was sufficient tomake the scheme *** scheme is still predominantly LDG2 and hence generated smaller dissipation and dispersion errors than the LDG *** experiments are performed to validate the *** general,the numerical results are very promising and indicate that the approach has a great potential for higher dimension Korteweg-de Vries(KdV)type problems.

关键词： Spectral volume LDG2 LDG higher spatial derivative terms KDV Fourier analysis

A High Order Spectral Volume Formulation for Solving Equations Containing Higher Spatial Derivative Terms:Formulation and Analysis for Third Derivative Spatial Terms Using the LDG Discretization Procedure

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Computational Physics 2011年第10期10卷 1257-1279页

作者： ravi kannan CFD Research Corporation 215Wynn DriveHuntsvilleAL 35805USA

In this paper,we develop a formulation for solving equations containing higher spatial derivative terms in a spectral volume(SV)context;more specifically the emphasis is on handling equations containing third derivative *** formulation is based on the LDG(Local Discontinuous Galerkin)flux discretization method,originally employed for viscous equations containing second derivatives.A linear Fourier analysis was performed to study the dispersion and the dissipation properties of the new *** Fourier analysis was utilized for two purposes:firstly to eliminate all the unstable SV partitions,secondly to obtain the optimal SV *** experiments are performed to illustrate the capability of this *** this formulation is extremely local,it can be easily parallelized and a h-p adaptation is relatively straightforward to *** general,the numerical results are very promising and indicate that the approach has a great potential for higher dimension Korteweg-de Vries(KdV)type problems.

关键词： Spectral volume LDG higher spatial derivative terms KDV Fourier analysis

Improving the High Order Spectral Volume Formulation Using a Diffusion Regulator

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Computational Physics 2012年第6期12卷 247-260页

作者： ravi kannan Zhijian Wang CFD Research Corporation 215Wynn DriveHuntsvilleAL 35805USA Iowa State University Howe HallAmesIA 50011USA

The concept of diffusion regulation(DR)was originally proposed by Jaisankar for traditional second order finite volume Euler *** was used to decrease the inherent dissipation associated with using approximate Riemann *** this paper,the above concept is extended to the high order spectral volume(SV)*** DR formulation was used in conjunction with the Rusanov flux to handle the inviscid flux *** experiments were conducted to compare and contrast the original and the DR *** experiments demonstrated(i)retention of high order accuracy for the new formulation,(ii)higher fidelity of the DR formulation,when compared to the original scheme for all orders and(iii)straightforward extension to Navier Stokes equations,since the DR does not interfere with the discretization of the viscous *** general,the 2D numerical results are very promising and indicate that the approach has a great potential for 3D flow problems.

关键词： Diffusion regulation spectral volume high-order Rusanov flux Navier Stokes equations

Mercury remediation potential of a mercury resistant strain Sphingopyxis ***2 isolated from contaminated soil

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2017年第1期29卷 128-137页

作者： Khandaker Rayhan Mahbub kannan Krishnan ravi Naidu Mallavarapu Megharaj Global Centre for Environmental Remediation(GCER) Cooperative Research Centre for Contamination Assessment and Remediation of the Environment(CRC-CARE)Faculty of Science and Information TechnologyThe University of NewcastleCallaghanNSW 9308Australia.

A mercury resistant bacterial strain SE2 was isolated from contaminated *** 16 s rRNA gene sequencing confirms the strain as Sphingopyxis belongs to the Sphingomonadaceae family of the α-Proteobacteria *** isolate showed high resistance to mercury with estimated concentrations of Hg that caused 50%reduction in growth（EC_（50）） of 5.97 and 6.22 mg/L and minimum inhibitory concentrations（MICs） of 32.19 and 34.95 mg/L in minimal and rich media,*** qualitative detection of volatilized mercury and the presence of mercuric reductase enzyme proved that the strain SE2 can potentially remediate ***-QQQ-MS analysis of the remaining mercury in experimental broths indicated that a maximum of 44%mercury was volatilized within 6 hr by live SE2 *** a small quantity（23%） of mercury was accumulated in live cell *** no volatilization was caused by dead cells,sorption of mercury was *** mercuric reductase gene merA was amplified and *** was observed among the amino acid sequences of mercuric reductase enzyme of different organisms from a-Proteobacteria and ascomycota groups,

关键词： Mercury resistance Sphingopyxis Mercury volatilization Mercury remediation Mercury reductase

Downwash airflow distribution pattern of hexa-copter unmanned aerial vehicles

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

International Journal of Agricultural and Biological Engineering 2024年第4期17卷 24-34页

作者： Dengeru Yallappa Ramasamy Kavitha Allimuthu Surendrakumar kannan Balaji Balakrishnan Suthakar Ayyasamy Paramasivam Mohan Kumar Yathendranaik ravi Narayananaik Ashoka Kumar Kavan Department of Farm Machinery and Power Engineering Agricultural Engineering College and Research InstituteTamil Nadu Agricultural UniversityCoimbatore

In recent times,the use of vertical take-off and landing(VTOL)multi-rotor Unmanned Aerial Vehicle(UAVs)for spraying chemical pesticides against weeds and pests has recently become *** current aerial spray application research is primarily focused on examining the influence of UAV spraying parameters such as flight height,travel speed,rotor configuration,droplet size,payload and wind *** downwash airflow velocity generated by the UAV rotor propeller has a significant impact on the droplet deposition process.A test rig was developed to measure the downwash airflow pattern generated by the rotor propeller of a *** this investigation,a six-rotor electric autonomous UAV sprayer was used to investigate the parameters and distribution laws of downwash airflow *** downwash airflow velocity was measured using portable anemometers mounted on the test rig at radial positions viz.,0 m,0.5 m,1 m,1.5 m and 2 m,perpendicular to(X)and parallel to the UAV’s flight direction(Y).The experiment was conducted at three levels of hover height,viz.,1 m,2 m and 3 m(Z)and three levels of payload,viz.,0 kg,5 kg,and 10 *** special downwash airflow distribution pattern was analysed using the Python programming language(Version 3.7).Results show that the downwash airflow velocity generated by the radial position of the UAV rotor is evenly distributed on the rotating loop and the standard deviation of the downwash airflow velocity is less than 0.5 m/*** maximum downwash airflow velocity of 13.8 m/s was observed below the rotor at 10 kg payload capacity,1 m hover height(Z),and 0.5 m in the *** minimum downwash wind field of 0.3 m/s was observed at 0 kg pay load capacity,1 m height,and 2 m in the *** downwash airflow velocity along each position in the radial direction of the rotor increases initially and then *** downwash airflow distribution results helps in mounting of spray nozzle configuration to drone sprayer which helps to

关键词： downwash air payload rotor propeller flight height distribution analysis flight direction

Effect of local longitudinal shortening on the transport of luminal contents through small intestine

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2019年第1期35卷 45-60,I0002页

作者： ravi Kant Avvari Sasi Institute of Technology and Engineering Tadepalligudem 534101India

A theoretical analysis of the rheological fluid flow due to peristalsis is studied. We have applied the classical lubrication theory to predict the near physiological behavior of the intestinal segment, mixing and transport. A parametric study involving the changes in local longitudinal shortening (LLS) magnitude, LLS spacing, fluid viscosity, wavelength of the wave, and occlusion of lumen caused by the wave provided insights into the dynamics of the peristalsis flow of a non-Newtonian fluid. LLS appear to have little significance in modulating the flow patterns that are caused by circular contraction alone. Results also indicate that there exists trade-off between the power requirement for peristalsis at a certain occlusion against the percentage LLS. LLS appear to be more advantageous to perform the peristalsis activity at higher occlusion than lower occlusion. Having mucosal folds in the inner lining of the intestine allows for one more advantage of slowing the transit due to increased friction factor and increase in time for absorption of the nutrients.

关键词： Circular contraction Local longitudinal shortening Lubrication theory

Multiferroism in Pr_2FeCrO_6 perovskite

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rare Earths 2018年第11期36卷 1175-1178页

作者： S.ravi Department of Physics Mepco Schlenk Engineering College

Pr2FeCrO6 perovskite crystallizes in an orthorhombic structure with R3c space group. Magnetic stuay nas revealed that Pr2FeCrO6 exhibits room-temperature ferromagnetism with a Curie temperature of about 562 K. Pr2FeCrO6 also exhibits weak ferroelectricity. Thus, given its ferroelectric and ferromagnetic na- ture, the Pr2FeCrO6 material can be considered as a multiferroic. In addition, due to its high Curie temperature and multiferroicity, it could be a promising candidate for spintronics applications.

关键词： Magnetic materials Double perovskite Magnetoresistance Spintronics Rare earths

Exploring nitrogen reduction reaction mechanisms in electrocatalytic ammonia synthesis:A comprehensive review

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2024年第5期92卷 681-697页

作者： Abhishek Umesh Shetty ravi Sankannavar School of Chemical and Materials Science Indian Institute of Technology GoaFarmagudiPonda 403401GoaIndia Department of Chemical Engineering M.S.Ramaiah Institute of TechnologyMSR NagarMSRIT PostBengaluru 560054KarnatakaIndia

The electrochemical nitrogen reduction reaction(eNRR)holds significant promise as a sustainable alternative to the conventional large-scale Haber Bosch process,offering a carbon footprint-free approach for ammonia *** the process is thermodynamically feasible at ambient temperature and pressure,challenges such as the competing hydrogen evolution reaction,low nitrogen solubility in electrolytes,and the activation of inert dinitrogen(N_(2))gas adversely affect the performance of ammonia *** hurdles result in low Faradaic efficiency and low ammonia production rate,which pose obstacles to the commercialisation of the *** have been actively designing and proposing various electrocatalysts to address these issues,but challenges still need to be resolved.A key strategy in electrocatalyst design lies in understanding the underlying mechanisms that govern the success or failure of the electrocatalyst in driving the electrochemical *** mechanistic studies,we gain valuable insights into the factors affecting the reaction,enabling us to propose optimised designs to overcome the *** review aims to provide a comprehensive understanding of the various mechanisms involved in eNRR on the electrocatalyst *** delves into the various mechanisms such as dissociative,associative,Mars-van Krevelen,lithium-mediated nitrogen reduction and surface hydrogenation mechanisms of nitrogen *** unravelling the intricacies of eNRR mechanisms and exploring promising avenues,we can pave the way for more efficient and commercially viable ammonia synthesis through this sustainable electrochemical process by designing an efficient electrocatalyst.

关键词： Green ammonia synthesis Electrolysis Electrocatalysis Nitrogen reductionreaction Electrochemical reaction pathways Reactionmechanism

The bioinformatics of next generation sequencing:a meeting report

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Journal of Molecular Cell Biology 2011年第3期3卷 147-150页

作者： ravi Shankar Studio of Computational Biology&Bioinformatics Institute of Himalayan Bioresource TechnologyCouncil of Scientific&Industrial Research(CSIR)PalampurHimachal PradeshIndia

The Studio of Computational Biology&Bioinformatics(SCBB),IHBT,CSIR,Palampur,India organized one of the very first national workshop funded by DBT,*** India,on the Bioinformatics issues associated with next generation sequencing *** course structure was designed by SCBB,*** workshop took place in the IHBT premise on 17 and 18 June 2010.

关键词： struc India workshop

An Efficient Image Analysis Framework for the Classification of Glioma Brain Images Using CNN Approach

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2020年第6期63卷 1133-1142页

作者： ravi Samikannu Rohini ravi Sivaram Murugan Bakary Diarra Faculty of Electrical Engineering Botswana International University of Science and TechnologyPalapyeBotswana Faculty of Computer Science Engineering Vivekanandha College of Engineering for WomenNamakkal637205India Department of Computer Networking Lebanese French UniversityErbil44001Iraq Institute of Applied Sciences University of SciencesTechniques and Technologies of BamakoBamakoMali

The identification of brain tumors is multifarious work for the separation of the similar intensity pixels from their surrounding *** detection of tumors is performed with the help of automatic computing technique as presented in the proposed *** non-active cells in brain region are known to be benign and they will never cause the death of the *** non-active cells follow a uniform pattern in brain and have lower density than the surrounding *** Magnetic Resonance(MR)image contrast is improved by the cost map construction *** deep learning algorithm for differentiating the normal brain MRI images from glioma cases is implemented in the proposed *** technique permits to extract the linear features from the brain MR image and glioma tumors are detected based on these extracted *** k-mean clustering algorithm the tumor regions in glioma are *** proposed algorithm provides high sensitivity,specificity and tumor segmentation accuracy.

关键词： Brain glioma features tumors classifications