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Prathap Haridoss

Bio: Prathap Haridoss is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Carbon nanotube & Proton exchange membrane fuel cell. The author has an hindex of 21, co-authored 61 publications receiving 1228 citations. Previous affiliations of Prathap Haridoss include Los Alamos National Laboratory & Plug Power.


Papers
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Journal ArticleDOI
TL;DR: In this paper, the variation of structural and physical properties of mesocarbon microbeads, a potential anode material for rechargeable lithium batteries, as a function of heat-treatment temperature in the range 400{endash}1100thinsp{degree}C was described.
Abstract: We describe the variation of structural and physical properties of mesocarbon microbeads, a potential anode material for rechargeable lithium batteries, as a function of heat-treatment temperature in the range 400{endash}1100thinsp{degree}C. Scanning electron microscope (SEM) studies indicated changes in the morphology of the mesocarbons with heat treatment. X-ray studies show that average crystallite size varies considerably with heat treatment. The d{sub 002} spacing decreases with increasing heat treatment temperatures. The electronic conductivity of the mesocarbon microbeads also increases substantially with increasing heat-treatment temperature. Based on thermogravimetrical analysis (TGA) and other measurements, we find that organic fractions volatilizes out of these carbons in two distinct stages. The observed weight loss correlates with the structural changes observed. We suggest that these observations are consistent with two types of hydrogenated fractions present in the {open_quotes}green{close_quotes} mesocarbons. {copyright} {ital 1998 Materials Research Society.}

9 citations

Journal ArticleDOI
TL;DR: In this article, the influence of nanocrystalline grain size on the solid particle erosion behavior of nickel was investigated, and it was observed that the higher erosion rates exhibited by 21 and 42-nm-grain size PED Ni samples were associated with the formation of adiabatic shear bands (ASBs) originating from the eroded surface and propagating into the eroded sample.
Abstract: The primary objective of the present study is to investigate the influence of nanocrystalline grain size on the solid particle erosion behavior of nickel. For the above purpose, 450-μm-thick nanocrystalline Ni coatings having the average grain sizes of 21, 42, 70, and 195 nm were obtained using pulsed electrodeposition (PED). All these samples along with bulk annealed Ni samples (43 μm grain size) were subjected to solid particle erosion using SiO2 particles as an erodent at a constant impact velocity of 45 m/s and two impact angles (30 and 90 deg). Erosion results indicate that bulk Ni and PED Ni coatings of grain sizes 195 and 70 nm exhibit the same erosion rate, while PED Ni coatings of 42 and 21 nm grain size exhibit marginally higher erosion rates with a clear trend of increasing erosion rate with decreasing grain size. It was also observed that the higher erosion rates exhibited by 21- and 42-nm-grain size PED Ni samples were associated with the formation of adiabatic shear bands (ASBs) originating from the eroded surface and propagating into the eroded sample. The experimental observations have been understood on the basis of a transition from a localization model for erosion for coarse-grained Ni (> 70 nm) to an ASB-induced erosion model for grain sizes less than 70 nm.

9 citations

Journal ArticleDOI
TL;DR: In this paper, the benefits of pre-oxidation process that generated nanowindows morphology on carbon surface that facilitated increased generation, effective utilization and minimizes the recombination of electron-hole pairs in turn triggered enhanced hydrogen production.

8 citations

Journal ArticleDOI
TL;DR: The graded NCA shows excellent reversibility of the H2↔H3 phase leading to low impedance development confirming the reduced surface reconstruction during the initial cycles, and its specific capacity is 65% higher than that of pristine NCA at 10C.
Abstract: LiNi1–x–yCoxAlyO2 (NCA) possessing a nano-/micro hierarchical architecture delivers a high specific capacity of 200 mAh/g with an upper cutoff voltage of 4.4 V. However, the structural reconstructi...

8 citations


Cited by
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08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

01 May 1993
TL;DR: Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems.
Abstract: Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

29,323 citations

Reference EntryDOI
31 Oct 2001
TL;DR: The American Society for Testing and Materials (ASTM) as mentioned in this paper is an independent organization devoted to the development of standards for testing and materials, and is a member of IEEE 802.11.
Abstract: The American Society for Testing and Materials (ASTM) is an independent organization devoted to the development of standards.

3,792 citations

Journal ArticleDOI
TL;DR: Increasing research efforts are carried out to design and develop more efficient anode electrocatalysts for DAFCs, which are attracting increasing interest as power sources for portable applications.
Abstract: Direct alcohol fuel cells (DAFCs) are attracting increasing interest as power sources for portable applications due to some unquestionable advantages over analogous devices fed with hydrogen.1 Alcohols, such as methanol, ethanol, ethylene glycol, and glycerol, exhibit high volumetric energy density, and their storage and transport are much easier as compared to hydrogen. On the other hand, the oxidation kinetics of any alcohol are much slower and still H2-fueled polymer electrolyte fuel cells (PEMFCs) exhibit superior electrical performance as compared to DAFCs with comparable electroactive surface areas.2,3 Increasing research efforts are therefore being carried out to design and develop more efficient anode electrocatalysts for DAFCs.

1,427 citations

Journal ArticleDOI
TL;DR: The faster kinetics of the alcohol oxidation and oxygen reduction reactions in ADAFCs, opening up the possibility of using less expensive metal catalysts, such as silver, nickel and palladium, makes the ADAFC a potentially low cost technology compared to acid direct alcohol fuel cell technology, which employs platinum catalysts.

777 citations