Srinivasa R. Bakshi

Bio: Srinivasa R. Bakshi is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Spark plasma sintering & Carbon nanotube. The author has an hindex of 34, co-authored 99 publications receiving 4515 citations. Previous affiliations of Srinivasa R. Bakshi include Naval Postgraduate School & Indian Institutes of Technology.

Microstructure and tribological behavior of spark plasma sintered iron-based amorphous coatings

Abstract: Spark plasma sintering (SPS) has been used to produce thick (∼400 μm) amorphous coatings of Fe48Cr15Mo14Y2C15B6 alloy composition on aluminum substrates. The coatings were fabricated using uniaxial pressure of 50 MPa over a range of temperatures (550–590 °C) below crystallization temperature (∼631 °C) of this glassy alloy. Under the investigated SPS processing parameters, the infiltration of the aluminum substrate material in the overlaid amorphous powder was observed resulting in composite amorphous coating. Detailed investigations on evolution of phases, microstructure, and interface characteristics in the amorphous coatings are presented. The amorphous coatings exhibited high surface hardness (∼880–1007 HV) and superior wear resistance (∼75–80% decrease in weight loss) compared to substrate material. The wear mechanisms were dominated by ploughing of soft aluminum phase in the interparticle regions, dislodging of amorphous particles, and microcutting (abrasion) of amorphous regions of the coatings.

In-situ formed graphene nanoribbon induced toughening and thermal shock resistance of spark plasma sintered carbon nanotube reinforced titanium carbide composite

Abstract: CNTs (2 wt%) reinforced TiC composite with WC (3.5 wt%) as sintering aid was densified using SPS technique at 1600 °C. In-situ formation of wide GNRs (Graphene nanoribbon) was observed due to CNT unzipping in TiC-WC-CNT (TWC) pellet. A phenomenal increase in fracture toughness (∼118%) was observed in TWC pellet compared to TiC. This significant improvement was due to novel toughening mechanisms like GNR grain wrapping, GNR crack bridging and crack bifurcation. Further, TWC pellet showed ∼48% improved thermal shock resistance compared to TiC, which could be due to the suppressed large thermal cracks by CNT and in-situ formed GNR.

Fast parallel algorithms for short-range molecular dynamics

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.

Phd by thesis

Abstract: Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Carbon Nanotubes: Present and Future Commercial Applications

Abstract: Worldwide commercial interest in carbon nanotubes (CNTs) is reflected in a production capacity that presently exceeds several thousand tons per year. Currently, bulk CNT powders are incorporated in diverse commercial products ranging from rechargeable batteries, automotive parts, and sporting goods to boat hulls and water filters. Advances in CNT synthesis, purification, and chemical modification are enabling integration of CNTs in thin-film electronics and large-area coatings. Although not yet providing compelling mechanical strength or electrical or thermal conductivities for many applications, CNT yarns and sheets already have promising performance for applications including supercapacitors, actuators, and lightweight electromagnetic shields.