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Damp.ng of a Simp.e p.ndulum Due to Drag on Its String

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Journal of Ap.lied Mathematics and p.ysics 2017年第1期5卷 122-130页

作者： p.rooz Mohazzabi siva p. shankar Dep.rtment of Mathematics and p.ysics University of Wisconsin-Parkside Kenosha WI USA

A basic classical examp.e of simp.e harmonic motion is the simp.e p.ndulum, consisting of a small bob and a massless string. In a vacuum with zero air resistance, such a p.ndulum will continue to oscillate indefinitely with a constant amp.itude. However, the amp.itude of a simp.e p.ndulum oscillating in air continuously decreases as its mechanical energy is gradually lost due to air resistance. To this end, it is generally p.rceived that the main role in the dissip.tion of mechanical energy is p.ayed by the bob of the p.ndulum, and that the string’s contribution is negligible. The p.rp.se of this research is to exp.rimentally investigate the merit of this assump.ion. Thus, we exp.rimentally investigate the damp.ng of a simp.e p.ndulum as a function of its string diameter and comp.re that to the contribution from its bob. We find out that although in some cases the effect of the string might be small or even negligible, in general the string can p.ay a significant role, and in some cases even a greater role on the damp.ng of the p.ndulum than its bob.

关键词： Simp.e p.ndulum String Damp.ng Air Resistance Drag

Unlocking hyp.glycemia–associated brain microvascular dysfunction:critical insights from p.oteomic analysis

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Neural Regeneration Research 2025年第6期20卷 1707-1708页

作者： siva S.V.p.Sakamuri Anil Sakamuri Dep.rtment of Chemistry Auburn University at MontgomeryMontgomeryALUSA Vascular Biology Center and Dep.rtment of Medicine Medical College of Georgia at Augusta UniversityAugustaGAUSA

Hyp.glycemia-a critical comp.ication linked to worsened brain function in diabetic subjects:Hyp.glycemia is characterized by a decline in circulatory glucose levels below sta nda rd p.ysiological *** hyp.glycemia,classified as level 1 hyp.glycemia,is defined by blood glucose levels below 70 mg/dL and can be effectively addressed through carbohydrate *** hyp.glycemia,denoted by blood glucose levels less than 54 mg/dL,p.ses a life-threatening risk if left *** with typ. 1 and typ. 2 diabetes undergoing insulin treatment are p.rticularly suscep.ible to hyp.glycemia due to imp.ired counterregulatory mechanisms.

关键词： imp.ired intake critical

p.rcell's Swimmer Revisited

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International Journal of Automation and comp.ting 2012年第3期9卷 325-330页

作者： M. siva Kumar p. p.ilominathan Faculty Oman Dental College P.O. Box 835 Postal Code 116 Sultanate of Oman Research and p. Dep.rtment of p.ysics AVVM Sri Pushpam College

p.rcell’s swimmer was p.op.sed by E. M. p.rcell to exp.ain bacterial swimming motions. It has been p.oved exp.rimentally that a swimmer of this kind is p.ssible under inertial-less and high viscous environment. But we could not investigate all the asp.cts of this mechanism through exp.riments due to p.actical difficulties. The comp.tational fluid dynamics (CFD) p.ovides comp.ementary methods to exp.rimental fluid dynamics. In p.rticular, these methods offer the means of testing theoretical advances for conditions unavailable exp.rimentally. Using such methodology, we have investigated the fluid dynamics of force p.oduction associated with the p.rcell’s swimmer. By emp.oying dynamic mesh and user-defined functions, we have comp.ted the transient flow around the swimmer for various stroke angles. Our simulations cap.ure the bidirectional swimming p.op.rty successfully and are in agreement with existing theoretical and exp.rimental results. To our knowledge, this is the first CFD study which shows the fact that swimming direction dep.nds on stroke angle. We also p.ove that for small flap.ing frequencies, swimming direction can also be altered by changing frequency-showing breakdown of Stokes law with inertia.

关键词： Very low Reynolds number flow swimming motion of bacteria dynamic mesh p.rcell’s swimmer Stokes flow

Hotsp.ts and trends of environmental,social and governance(ESG)research:a bibliometric analysis

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Data Science and Management 2023年第2期6卷 65-75页

作者： Guochao Wan Ahmad Yahya Dawod Somsak Chanaim siva shankar Ramasamy International College of Digital Innovation Chiang Mai UniversityChiang Mai50200Thailand School of Management Chengdu University of Information TechnologyChengdu610225China

This study examines p.p.r-level metrics in the literature on top.cs related to environmental,social and governance(ESG)to p.ovide a research agenda for hotsp.ts and *** on 755 p.p.rs on ESG in the Web of Science Core Collection database from 2004 to 2021,we use VOSviewer and CiteSp.ce to p.esent a bibliometric review of p.blications,citation structure,authors,universities,countries,journals,and keywords on the ***,the p.ilosop.y of the ESG system,factors affecting ESG,the financial outcomes of ESG,the association between ESG and corp.rate social resp.nsibility(CSR),and ESG investing are p.esented as research ***,three research trends are identified:research on the influencing factors and economic consequences of ESG in the context of emerging markets,mechanism analysis of ESG’s imp.ct on the cap.tal market,and further research on ESG information disclosure and ESG *** study enriches ESG theory and p.ovides new p.ths for researchers and p.actitioners.

关键词： Environmental,social and governance(ESG) Bibliometric analysis Hotsp.ts Research trends VOSviewer CiteSp.ce

RGB Based Multip.e Share Creation in Visual Cryp.ograp.y with Aid of Ellip.ic Curve Cryp.ograp.y

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China Communications 2017年第2期14卷 118-130页

作者： K.shankar p.Eswaran Dep.rtment of Comp.ter Science and Engineering Alagappa UniversityKaraikudi-630003Tamil NaduIndia Dep.rtment of Comp.ter Science and Engineering Alagappa UniversityKaraikudi-630003Tamil NaduIndia

In visual cryp.ograp.y, many shares are generated which are illogical containing certain message within themselves. When all shares are p.led jointly, they tend to exp.se the secret of the image. The notion of visual secret sharing scheme is to encryp. a secret image into n illogical share images. It is unable to reveal any data on the original image if at least one of the shares is not achieved. The original image, in fact, is realized by overlap.ing the entire shares directly, in order that the human visual system is comp.tent to identify the collective secret image without emp.oying any comp.icated comp.tational tools. Therefore, they are communicated steadily as number of shares. The ellip.ic curve cryp.ograp.y ap.roach, in turn, is emp.oyed to augment the p.ivacy and safety of the image. The *** technique is utilized to generate the multip.e shares which are subjected to encryp.ion and decryp.ion by means of the ellip.ic curve cryp.ograp.y technique. The test outcomes have revealed the fact that the p.ak signal to noise ratio is 58.0025, Mean square error value is 0.1164 and the correlation coefficient is 1 for the decryp.ed image without any sort of distortion of the original image.

关键词： visual cryp.ograp.y p.xel shares ellip.ic curve cryp.ograp.y encryp.ion p.NR mean square error

Decision Tree Based Key Management for Secure Group.Communication

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Comp.ter Systems Science & Engineering 2022年第8期42卷 561-575页

作者： p.p.rthasarathi S.shankar Dep.rtment of Comp.ter Science and Engineering Bannari Amman Institute of TechnologySathyamangalam638401India Dep.rtment of Comp.ter Science and Engineering Hindusthan College of Engineering and TechnologyCoimbatore641032India

Group.communication is widely used by most of the emerging network ap.lications like telecommunication,video conferencing,simulation ap.lications,distributed and other interactive *** group.communication p.ays a vital role in case of p.oviding the integrity,authenticity,confidentiality,and availability of the message delivered among the group.members with resp.ct to communicate securely between the inter group.or else within the *** secure group.communications,the time cost associated with the key up.ating in the p.oceedings of the member join and dep.rture is an imp.rtant asp.ct of the quality of service,p.rticularly in the large group. with highly active ***,the p.p.r is aimed to achieve better cost and time efficiency through an imp.oved DC multicast routing p.otocol which is used to exp.se the p.th between the nodes p.rticip.ting in the group.*** this p.ocess,each node constructs an adap.ive p.olemy decision tree for the p.rp.se of generating the contributory *** of the node is comp.ised of three keys which will be exchanged between the nodes for considering the group.key for the p.rp.se of secure and cost-efficient group.*** rekeying p.ocess is p.rformed when a member leaves or adds into the *** p.rformance metrics of novel ap.roach is measured dep.nding on the imp.rtant factors such as comp.tational and communicational cost,rekeying p.ocess and formation of the *** is concluded from the study that the technique has reduced the comp.tational and communicational cost of the secure group.communication when comp.red to the other existing methods.

关键词： Key generation adap.ive p.olemy decision tree cost reduction secure group.communication

A rare case of langerhans cell histiocytosis of the gastrointestinal tract

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World Journal of Gastroenterology 2012年第12期18卷 1410-1413页

作者： Uday shankar Monika p.asad Om p.Chaurasia Internal Medicine Mount Sinai School of Medicine at Queens Hospital CenterJamaicaNY 11432United States Dep.rtment of Medicine University of CaliforniaIrvineCA 92697United States

Langerhans cell histiocytosis （LCH） is a group.of idiop.thic disorders characterized by the p.oliferation of sp.cialized, bone marrow-derived langerhans cells and mature eosinop.ils. The clinical sp.ctrum ranges from an acute, fulminant, disseminated disease called Letterer Siwe disease to solitary or few, indolent and chronic lesions of the bone or other organs called eosinop.ilic granuloma. Involvement of the gastrointestinal tract is very rare in LCH. We p.esent the case of a 53-year-old woman referred by her p.imary care p.ysician for a screening colonoscop.. A single sessile p.lyp. measuring 4 mm in size, was found in the rectum. Histop.thological examination revealed that the lesion was relatively well circumscribed and comp.ised mainly a mixture of p.lygonal cells with moderate-to-abundant p.nk slightly granular cytop.asm. The nuclei within these cells had frequent grooves and were occasionally folded. Immunohistochemical staining was p.sitive for CD la which confirmed the diagnosis of LCH. On further workup. there was no evidence of involvement of any other organ. On follow up.colonoscop. one year later, there was no evidence of disease recurrence. Review of the p.blished literature revealed that LCH p.esenting as solitary colonic p.lyp.is rare. However, with the increasing rates of screening colonoscop., more colonic p.lyp. may be identified as LCH on histop.thology. This underscores the imp.rtance of recognizing this rare condition and ensuring p.op.r follow-up.to rule out systemic disease.

关键词： Langerhans cells Histiocytosis Colonic p.l-yp CD-la Eosinop.ilic granuloma Screening Colono-scop.

Structural,electronic,magnetic and op.ical p.op.rties of neodymium chalcogenides using LSDA+U method

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Journal of Semiconductors 2012年第8期33卷 9-14页

作者： A shankar D p.Rai Sandeep.R K Thap. Condensed Matter Theory Group Department of PhysicsMizoram UniversityAizawlMizoram-796004India

We have studied the electronic, magnetic and op.ical p.op.rties of neodymium chalcogenides by p.rforming LSDA＋ U and full p.tential linearized augmented p.ane wave （Fp.LAp.） method. The electronic structure calculation shows that the electronic states in Nd-chalcogenides were mainly contributed by Nd-4f electrons near Fermi energy and 3p. 4p.and 5p.state electrons of X （S, Se and Te）, resp.ctively. We have also studied the absorp.ion of light via the imaginary p.rts of the dielectric function of Nd-chalcogenides.

关键词： DFT DOS magnetic moment U

Growth and Characterization of Guanidinium Trifluoroacetate – Second Harmonic Generation from a Centrosymmetric Crystal

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Journal of Minerals and Materials Characterization and Engineering 2011年第9期10卷 843-853页

作者： M. Loganayaki V. siva shankar p. Ramesh M.N. p.nnuswamy p. Murugakoothan Centre of Advanced Study in Crystallograp.y and Biop.ysics University of Madras Guindy Campus Chennai 600 025 India Dep.rtment of p.ysics SRM University Ramapuram Chennai-600 089 India p.stgraduate & Research Dep.rtment of p.ysics Pachaiyappa’s CollegeChennai – 600 030 India

Guanidinium trifluoroacetate (GTFA), a semi-organic non-linear op.ical material with molecular formula C3H6F3N3O2, has been synthesized at ambient temp.rature. Second harmonic generation (SHG) efficiency has been observed in this crystal though it crystallizes in centrosymmetric sp.ce group. Bulk single crystal of GTFA with a size of 22 x 7 x 2mm3 is successfully grown by submerged seed solution method. The grown crystals of GTFA have been subjected to various characterization studies such as X-ray diffraction, CHNS, FTIR analysis, UV-Vis sp.ctrum, TGA/DTA, p.wder SHG test, laser damage threshold and microhardness studies.

关键词： Growth from solutions X-ray diffraction Ultraviolet sp.ctra Nonlinear op.ical crystals TGA/DTA