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Inertia-Centric Stability Analysis of a planar Uniform Dust Molecular Cloud with Weak Neutral-Charged Dust Frictional Coupling

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plasma Science and Technology 2014年第5期16卷 433-447页

作者： p.K.KARMAKAR b.bORAH Department of physics Tezpur University

This paper adopts an inertia-centric evolutionary model to study the excitation mechanism of new gravito-electrostatic eigenmode structures in a one-dimensional（1-D） planar self-gravitating dust molecular cloud（DMC） on the Jeans scale.A quasi-neutral multi-fluid consisting of warm electrons,warm ions,neutral gas and identical inertial cold dust grains with partial ionization is *** grain-charge is assumed not to vary at the fluctuation evolution time *** neutral gas particles form the background,which is weakly coupled with the collapsing grainy plasma *** gravitational decoupling of the background neutral particles is justifiable for a higher inertial mass of the grains with higher neutral population density so that the Jeans mode frequency becomes reasonably *** physical basis is the Jeans assumption of a self-gravitating uniform medium adopted for fiducially analytical simplification by neglecting the zero-order ***,the equilibrium is justifiably treated initially as ＂homogeneous＂.The efficacious inertial role of the thermal species amidst weak collisions of the neutral-charged grains is taken into account.A standard multiscale technique over the gravito-electrostatic equilibrium yields a unique pair of Korteweg-de Vries（KdV） *** is integrated numerically by the fourth-order Runge-Kutta method with multi-parameter variation for exact shape ***,the model is conducive for the propagation of new conservative solitary spectral *** basic physics,parametric features and unique characteristics are *** results go qualitatively in good correspondence with the earlier observations made by *** applications relevant to space and astrophysical environments are concisely highlighted.

关键词： molecular cloud pair KdV equations solitary patterns

Graphs of NMS Flows on S^3 with Knotted Saddle Orbits and No Heteroclinic Trajectories

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Acta Mathematica Sinica,English Series 2007年第12期23卷 2213-2224页

作者： b.CAMpOS p.VINDEL Dpt.Matemàtiques Universitat JaumeI

We consider NMS systems on S^3 without heteroclinic trajectories connecting two saddles orbits and we build the dual graphs associated with this kind of flows. We prove that flows coming from essential attachments of ... 详细信息

关键词： NMS systems Wada operations dual graphs

Quadratic convective flow of radiated nano-Jeffrey liquid subject to multiple convective conditions and Cattaneo-Christov double diffusion

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Applied Mathematics and Mechanics(English Edition) 2018年第9期39卷 1311-1326页

作者： p.b.SAMpATH KUMAR b.MAHANTHESH b.J.GIREESHA S.A.SHEHZAD Department of Studies and Research in Mathematics Kuvempu University Department of Mathematics Christ University Department of Mathematics COMSATS Institute of Information Technology

A nonlinear flow of Jeffrey liquid with Cattaneo-Christov heat flux is investigated in the presence of nanoparticles. The features of thermophoretic and brownian movement are retained. The effects of nonlinear radiation, magnetohydrodynamic(MHD), and convective conditions are accounted. The conversion of governing equations into ordinary differential equations is prepared via stretching transformations. The consequent equations are solved using the Runge-Kutta-Fehlberg(RKF) method. Impacts of physical constraints on the liquid velocity, the temperature, and the nanoparticle volume fraction are analyzed through graphical illustrations. It is established that the velocity of the liquid and its associated boundary layer width increase with the mixed convection parameter and the Deborah number.

关键词： nonlinear convection Jeffrey liquid nanoliquid convective condition thermophoretic brownian motion

Evaluation of pedestrian crossing speed change patterns at unprotected mid-block crosswalks in India

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Journal of Traffic and Transportation Engineering(English Edition) 2020年第6期7卷 832-842页

作者： b.Raghuram Kadali p.Vedagiri Department of Civil Engineering National Institute of Technology WarangalWarcmgal 506004India Department of Civil Engineering Indian Institute of Technology BombayMumbai 400076India

The pedestrian crossing speed is one of the important factors in pedestrian crossing facility *** studies have shown that the pedestrian crossing speed is influenced by availability of green time at signalized crosswalks and pedestrian characteristics such as gender and ***,the effects of vehicular time gap and additional pedestrian behavioural characteristics on pedestrian crossing speed patterns have not been examined at unprotected(un-signalized)mid-block *** present study examines the pedestrian crossing speed change patterns considering the effect of vehicular time gap and pedestrian behavioural characteristics such as rolling behaviour,path change,etc.,at selected unprotected mid-block crosswalk locations under mixed traffic conditions in *** graphic survey has been conducted at eight selected unprotected mid-block crosswalk locations in Mumbai City for two to three hours duration during normal weather *** data was mined using AVS video editor software,and the extracted data includes pedestrian speed,pedestrian characteristics(gender and age),pedestrian behaviour(rolling behaviour,path change,etc.),vehicle characteristics(type and speed of the vehicle)and traffic *** crossing speed change patterns(whether pedestrian is changing speed or not while crossing a road)was considered as a binary variable and a logistic regression model was developed with vehicular gaps and other pedestrian behavioural characteristics as independent *** results revealed that there is a reduction in pedestrian crossing speed change behaviour with an increase in vehicular gap size at unprotected mid-block *** younger pedestrians have more probability of exhibiting crossing speed change patterns as compared to the elderly pedestrians at mid-block ***,it is identified that there is an increase in pedestrian crossing speed with increase in vehicle speed as well as heavy vehicle type

关键词： pedestrian behavior Crossing Speed patterns Mid-block Vehicle gap

Slurry wear characteristics of zinc-based alloys： Effects of sand content of slurry, silicon addition to alloy system and traversal distance

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中国有色金属学会会刊：英文版 2009年第2期19卷 277-286页

作者： b.K. pRASAD, O.p. MODI Advanced Materials and processes Research Institute （CSIR） Bhopal-462026 India

这调查处理在泥浆上与标本和泥浆作文以及遍历距离的效果相关的观察穿基于锌的合金的反应。合金的作文被把 4% 硅加到它改变。泥浆作文通过在被推迟在的 060% 的范围改变沙粒子的集中被改变(液体) 电解质。电解质包含了集中的硫的酸在水... 详细信息

这调查处理在泥浆上与标本和泥浆作文以及遍历距离的效果相关的观察穿基于锌的合金的反应。合金的作文被把 4% 硅加到它改变。泥浆作文通过在被推迟在的 060% 的范围改变沙粒子的集中被改变(液体) 电解质。电解质包含了集中的硫的酸在水的 10 L 溶解了的 4 g 钠氯化物和 5 mL。泥浆穿测试在 15500 km 的遍历距离范围上以 7.02 m/s 的速度被进行。wear 率开始与遍历距离增加了，达到了最大值并且不管标本和测试环境，此后减少了。然而， wear 率山峰比液体唯一的媒介在加沙环境的液体是不太突出的。进一步，在液体唯一的媒介的 wear 率山峰在包含泥浆的沙比那座出现在更短的遍历距离。到电解质的沙粒子的增加把样品的 wear 率归结为取决于泥浆的沙集中的 5%15% 。而且，中介(40%) 沙内容导致了最大值穿率什么时候与相比在加沙媒介的液体。然而，这最大值是静止的不到在里面液体唯一的媒介。包含更高受不了的合金的硅比当在液体唯一的媒介测试了时，免费合金取样的硅穿率。相反，而混合回答在包含 60% 沙的泥浆被注意，趋势加 20% 和 40% 沙环境在液体逆行。在后者盒子中，当一个相反的趋势在更长的遍历距离被观察时，硅的存在开始证明有害。样品的 wear 反应在试验性的条件的一个给定的集合以他们象硅和占优势的材料移动机制一样的 microconstituents 的特定的特征被讨论。合金的观察行为也通过他们的影响表面和表面下的区域的特征进一步被证实。

关键词：锌基合金磨损特性硅合金泥浆加砂远程系统渣浆泵测试环境

The great catastrophe: causes of the permo-Triassic marine mass extinction

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National Science Review 2024年第1期11卷 37-50页

作者： paul b.Wignall David p.G.bond School of Earth & Environment University of Leeds School of Environmental Sciences University of Hull

The marine losses during the permo-Triassic mass extinction were the worst ever experienced. All groups were badly affected, especially amongst the benthos(e.g. brachiopods, corals, bryozoans, foraminifers,ostracods). planktonic populations underwent a fundamental change with eukaryotic algae being replaced by nitrogen-fixing bacteria, green-sulphur bacteria, sulphate-reducing bacteria and prasinophytes. Detailed studies of boundary sections, especially those in South China, have resolved the crisis to a ～55 kyr interval straddling the permo-Triassic boundary. Many of the losses occur at the beginning and end of this interval painting a picture of a two-phase extinction. Improved knowledge of the extinction has been supported by numerous geochemical studies that allow diverse proposed extinction mechanisms to be studied. A transition from oxygenated to anoxic-euxinic conditions is seen in most sections globally, although the intensity and timing shows regional variability. Decreased ocean ventilation coincides with rapidly rising temperatures and many extinction scenarios attribute the losses to both anoxia and high *** kill mechanisms include ocean acidification for which there is conflicting support from geochemical proxies and, even less likely, siltation(burial under a massive influx of terrigenous sediment) which lacks substantive sedimentological evidence. The ultimate driver of the catastrophic changes at the end of the permian was likely Siberian Trap eruptions and their associated carbon dioxide emissions with consequences such as warming, ocean stagnation and acidification. Volcanic winter episodes stemming from Siberian volcanism have also been linked to the crisis, but the short-term nature of these episodes(pid warming during the crisis makes this an unlikely cause. Finally, whilst the extinction is well studied in equatorial latitudes, a different history is found in northern boreal latitudes

关键词： ocean anoxia ocean acidification siltation productivity collapse volcanic winter

Application of multi-criteria decision making methods for selection of micro-EDM process parameters

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Advances in Manufacturing 2014年第3期2卷 251-258页

作者： A.p.Tiwary b.b.pradhan b.bhattacharyya Department of Mechanical Engineering Sikkim Manipal Institute of TechnologyEast Sikkim.Majitar 737136.India Department of production Engineering Jadavpur UniversityKolkata 700032India

Ti-6A1-4V super alloy is an important engi- neering material with good strength to weight ratio and a wide range of applications in a number of engineering fields because of its excellent physical and mechanical properties. This work determines optimum process parameters such as pulse on time, peak current, gap voltage and flushing pressure, which influence the micro-electro discharge machining （EDM） process during machining of Ti-6AI-4V using combined methods of response surface methodology （RSM） and fuzzy-technique for order pref- erence by similarity to ideal solution （TOpSIS）. Central composite design （CCD） is used in the experimental investigation. A decision making model is developed to identify the optimum process parameters in the micro- EDM process, which influences several machining criteri- ons such as material removal rate （MRR）, tool wear rate （TWR）, overcut （OC） and taper. Triangular fuzzy numbers are used to determine the weighting factor for each process criterion. Further a fuzzy-TOpSIS method is used to select the most desirable factor level combinations. The proposed technique can be used to select optimal process parameters from various sets of combinations of process parameters in a micro-EDM process.

关键词： Micro-EDM - Ti-6A1-4V Fuzzy-techniquefor order preference by similarity to ideal solution(TOpSIS) Micromachining

Scour prevention in bottomless arch culverts

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International Journal of Sediment Research 2012年第2期27卷 213-225页

作者： b.M.CROOKSTON b.p.TULLIS Utah Water Research Laboratory Utah State University8200 Old Main HillLoganUT 84322 Utah State University Utah Water Research Laboratory8200 Old Main HillLoganUT 84322

bottomless arch culverts are employed as ecological bridges at road crossings with their most common application being fish *** simulated culvert streambed should mimic the existing natural channel but be engineered to resist erosion during high flow *** provide some design guidance for simulated streambed stability in culverts,a culvert streambed stability study was conducted using a 0.61-m(2-ft) diameter smooth-walled bottomless arch culvert featuring streambed materials ranging in size from pea gravel to *** culvert entrance geometries over a range of headwater depths(unsubmerged and submerged inlets conditions) were *** riprap stone-sizing stability relationships were evaluated,relative to the experimental data,to determine their potential applicability to arched bottomless culverts streambed stability *** general observations are discussed regarding the location and extent of scour events in bottomless culverts and incipient motion velocity variations between the bottomless arched culvert and a rectangular flume for the same substrate materials.

关键词： Scour prevention bottomless arch culvert Fish passage Riprap Gravel streambed

Modeling and simulation of centroid and inversion charge density in cylindrical surrounding gate MOSFETs including quantum effects

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Journal of Semiconductors 2013年第11期34卷 25-30页

作者： p.Vimala N.b.balamurugan Department of Electronics and Communication Engineering Thiagarajar College of Engineering

An analytical model for surrounding gate metal-oxide-semiconductor field effect transistors （MOS- FETs） considering quantum effects is presented. To achieve this goal, we have used a variational approach for solving the poisson and Schrodinger equations. This model is developed to provide an analytical expression for the inversion charge distribution function for all regions of the device operation. This expression is used to calculate the other important parameters like the inversion charge centroid, threshold voltage and inversion charge density. The calculated expressions for the above parameters are simple and accurate. The validity of this model was checked for the devices with different device dimensions and bias voltages. The calculated results are compared with the simulation results and they show good agreement.

关键词： surrounding gate MOSFETs energy quantization centroid inversion charge density