Perfluoropolyether Lubricant Interactions With Novel Overcoat via Coarse-Grained Molecular Dynamics

Vemuri, S. H.,Pil Seung Chung,Smith, R.,Geun-Young Yeom,Young In Jhon,Nae-Eung Lee,Biegler, L. T.,Jhon, M. S. IEEE 2012 IEEE transactions on magnetics Vol.48 No.11

<P>In this paper, we investigated physiochemical properties of new lubricant candidates for head-disk interface through various perfluoropolyether lubricant films on diamond, diamond-like carbon, and graphene overcoat surfaces via large scale coarse-grained bead-spring molecular dynamics stemming from the atomistic theory. Lubricant film conformations were characterized by investigating perpendicular component of molecular conformation, which determines the thickness of monolayer lubricant film. The distribution of functional endgroups and the mobility were analyzed via self-diffusion process. Here, we illustrate the effects of endgroup structure and carbon-surface structure on the film conformation and the mobility by expanding the multiscale simulation methodology and select candidates for future HDI design.</P>

Analysis of Australia-Korea Economic Relations : Lessons and Implications for the Future

Vemuri, S. Ram 이화여자대학교 사회과학연구소 2008 사회과학연구논총 Vol.19 No.-

이 논문은 두 가지 목적을 두고 있다. 첫째,지난 50년간의 경제에서 배운 것의 주 교훈이라고 생각되는 것을 기술하는 것이고,다른 하나는 경제 관계를 설립하는 것에 있어서의 영향을 추적해 보는 것이다. 배움이 언제나 조촐한 꾸러미가 아닌 것처럼 지난 50년의 소개는 연대기 순에 의한 것이 아니다. 대신에 배움의 교훈에 대해,시스템과 가치들이 변화한 점에서,경제와 그것의 의미,내용,구조,수행, 전략과 실행 과 정책 관찰한 이야기로 접근했다. 그리고 경제 관계를 설립하는 것에서 배움의 교훈의 이론적 배경을 풍자함으로써,호주와 한국의 미래 관계 의미에 대한 간단한 관점을 제공할 것이다. This paper has two objectives. One, to sketch what I deem to be the main lessons of learning in economics over the past fifty years, and the other, to trace any impacts they had in establishing economic relations. The presentation of the past fifty years does not follow a chronological order, as learning does not occur in neat packages. Instead I have approached the lessons of learning as a narrative wherein I observe that systems have changed and values have shifted about economics and its meaning, content, structure, conduct, strategies, performances and policies. Having caricatured a theoretical backdrop of lessons of learning in establishing economic relations, I would then provide a brief perspective of the implications of future relationships between Australia and Korea.

Head-disk interface design in magnetic data storage

Vemuri, Sesha Hari,Chung, Pil Seung,Smith, Robert L.,Lee, Nae-Eung,Biegler, Lorenz T.,Jhon, Myung S. American Institute of Physics 2012 JOURNAL OF APPLIED PHYSICS - Vol.111 No.7

Importance of Volumetric Measurement Processes in Oncology Imaging Trials for Screening and Evaluation of Tumors as Per Response Evaluation Criteria in Solid Tumors

Vemuri, Ravi Chandra,Jarecha, Rudresh,Hwi, Kim Kah,Gundamaraju, Rohit,MaruthiKanth, Aripaka,Kulkarni, AravindRao,Reddy, Sundeep Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.5

Cancer, like any disease, is a pathologic biological process. Drugs are designed to interfere with the pathologic process and should therefore also be validated using a functional screening method directed at these processes. Screening for cancers at an appropriate time and also evaluating results is also very important. Volumetric measurement helps in better screening and evaluation of tumors. Volumetry is a process of quantification of the tumors by identification (pre-cancerous or target lesion) and measurement. Volumetric image analysis allows an accurate, precise, sensitive, and medically valuable assessment of tumor response. It also helps in identifying possible outcomes such disease progression (PD) or complete response as per Response Evaluation Criteria in Solid Tumors (RECIST).

Hyperbolic Averaged Models for Describing Dispersion Effects in Chromatographs and Reactors

Vemuri Balakotaiah 한국화학공학회 2004 Korean Journal of Chemical Engineering Vol.21 No.2

We show that dispersion effects due to local velocity gradients and transverse molecular diffusion in chromatographs and chemical reactors can be better described in terms of averaged models that are hyperbolic in the longitudinal coordinate and time, and with an effective local time or length scale in place of the traditional axial dispersion coefficient. This description not only eliminates the use of artificial exit boundary conditions but also inconsistencies such as upstream propagation and infinite speed of signals associated with the traditional parabolic averaged models. We also show that the hyperbolic models can describe dispersion effects accurately and have a much larger region of validity in the physical parameter space compared to the traditional parabolic models. Our method of obtaining averaged models from the governing partial differential equations is based on the Lyapunov-Schmidt technique of classical bifurcation theory and is rigorous. We illustrate our approach using three well known chemical engineering problems.

Hyperbolic Averaged Models for Describing Dispersion Effects in Chromatographs and Reactors

Balakotaiah, Vemuri 한국화학공학회 2004 Korean Journal of Chemical Engineering Vol.21 No.2

We show that dispersion effects due to local velocity gradients and transverse molecular diffusion in chromatographs and chemical reactors can be better described in terms of averaged models that are hyperbolic in the longitudinal coordinate and time, and with an effective local time or length scale in place of the traditional axial dispersion coefficient. This description not only eliminates the use of artificial exit boundary conditions but also inconsistencies such as upstream propagation and infinite speed of signals associated with the traditional parabolic averaged models. We also show that the hyperbolic models can describe dispersion effects accurately and have a much larger region of validity in the physical parameter space compared to the traditional parabolic models. Our method of obtaining averaged models from the governing partial differential equations is based on the Lyapunov-Schmidt technique of classical bifurcation theory and is rigorous. We illustrate our approach using three well known chemical engineering problems.

Analysis of Australia-Korea Economic Relations: Lessons and Implications for the Future

S. Ram Vemuri 이화여자대학교 이화사회과학원 2008 사회과학연구논총 Vol.19 No.-

이 논문은 두 가지 목적을 두고 있다. 첫째, 지난 50년간의 경제에서 배운 것의 주교훈이라고 생각되는 것을 기술하는 것이고, 다른 하나는 경제 관계를 설립하는 것에 있어서의 영향을 추적해 보는 것이다. 배움이 언제나 조촐한 꾸러미가 아닌 것처럼 지난 50년의 소개는 연대기 순에 의한 것이 아니다. 대신에 배움의 교훈에 대해, 시스템과 가치들이 변화한 점에서, 경제와 그것의 의미, 내용, 구조, 수행, 전략과 실행 과 정책 관찰한 이야기로 접근했다. 그리고 경제 관계를 설립하는 것에서 배움의 교훈의 이론적 배경을 풍자함으로써, 호주와 한국의 미래 관계 의미에 대한 간단한 관점을 제공할 것이다. This paper has two objectives. One, to sketch what I deem to be the main lessons of learning in economics over the past fifty years, and the other, to trace any impacts they had in establishing economic relations. The presentation of the past fifty years does not follow a chronological order, as learning does not occur in neat packages. Instead I have approached the lessons of learning as a narrative wherein I observe that systems have changed and values have shifted about economics and its meaning, content, structure, conduct, strategies, performances and policies. Having caricatured a theoretical backdrop of lessons of learning in establishing economic relations, I would then provide a brief perspective of the implications of future relationships between Australia and Korea.

An Estimation of the Latent Bilateral Trade between India and Pakistan Using Panel Data Methods

VIJAY K. VEMURI,SHAHID SIDDIQI 연세대학교 동서문제연구원 2011 Global economic review Vol.40 No.1

The aim of this paper is to estimate the potential for trade between India and Pakistan, assuming a normalized neighborly relationship. We used an augmented gravity model with a panel data for 21 years. This paper utilizes the panel fixed effects decomposition and Hausman and Taylor estimation methods to estimate the effect of time-invariant variables on the volume of potential trade. The present volume of trade is dwarfed by our estimates of the potential trade. This seems to ratify the expectation of businesses on both sides. It would appear that the development of a bilateral relationship between India and Pakistan, in the context of regionalization, should be motivated by strong economic considerations. It would include sectordriven as well as market-access approaches. While the theoretical background appears subtle, strategic market consequences arise from the dynamics of regional market structure. Assuming a positive relationship between trade and per capita income, here is a peace dividend that is difficult to ignore in a regional environment of oppressive poverty.

Managing Selective Linkages in a Global Economic Environment

S. Ram Vemuri 한국전문경영인학회 2004 專門經營人硏究 Vol.7 No.2

Temperature Profile in the Presence of Hotspots in Heat Assisted Magnetic Recording

Hyung Min Kim,Vemuri, S. H.,Chung, P. S.,Young In Jhon,Nae-Eung Lee,Geun-Young Yeom,Jhon, M. S. IEEE 2012 IEEE transactions on magnetics Vol.48 No.11

<P>Recently, the demands for increasing memory capacities in hard disk drives (HDDs) has resulted in state-of-the-art technologies including heat assisted magnetic recording (HAMR) with significantly higher operating temperatures. HAMR results in swift degradation of current lubricant and carbon overcoat (COC) materials, leading to magnetic media corrosion which is detrimental to HDD operation. In addition, the lack of thorough understanding of the temperature profiles arising from the hotspot and energy management throughout these materials also exacerbates the problem. To address this issue, in this paper we will focus on the COC and investigate the transient heat transfer in various examples of nanoscale thin films when a hot spot is created via lattice Boltzmann method (LBM) since traditional conduction models like Fourier law are not accurate due to dominant sub-continuum effects. LBM originates from the Boltzmann transport equations (BTEs) and is computationally efficient due to easy parallelization with convenient handling of complex geometries. Our results of the heat transfer mechanism and temperature profiles show that Fourier equation under-predicts the peak temperature rise at the center of the hot-spot as the system size approaches the nanoscale domain. Applying LBM to a multilayered system, we observe a temperature slip along the interface of two materials indicated by the broken isothermal contours, as the heat is confined to a single layer. Using LBM, we then explore a novel graphene overcoat which has outstanding thermo-mechanical properties, and thereby extremely compatible in HAMR applications.</P>