188,758 research outputs found
Krishnan and the sampling theorem
No full textKrishnan loved mathematics and those who knew him had
great respect and even awe for his skill as a mathematician. However, he chose to publish in mathematics just once, and for future generations this particular work of Krishnan remains just about the only source from which to gain a glimpse of his mathematics. This work is outlined, and it is shown that his main result is essentially equivalent to the
sampling theorem of Shannon that appeared a little later. While conventional wisdom viewed the sampling theorem as a powerful engineering tool in signal processing, Krishnan saw in his main result a rich source of deep mathematical identities
Data for: Enhanced elastomer toughness and fracture properties imparted by chemically reactive flat nanoparticles
No full textThe files named "Fsweep_NAME", where "NAME" refers to NC45, NG45, CB45, CF45-PARL, CF45-PERP, and BASE, contain frequency-sweep dynamic mechanical analysis (DMA) data acquired at 30 °C for the respective elastomers. Measurements were made in the dual-cantilever mode using a strain amplitude of 0.1%.The files named "Tsweep_NAME" contain temperature-sweep DMA data acquired at a constant heating rate of 3 °C/min, a strain amplitude of 0.1 %, and a strain frequency of 1 Hz.The files named "TENSILE_NAME" contain stress vs. strain data acquired on dumbbell specimens with a gauge length of 20 mm, a width of 2 mm, and a thickness of 2 mm, at a constant extension rate of 500 mm/min. The files named "CYCLIC_TENSILE_NAME" contain stress vs. strain data for these specimens using a triangular strain waveform, consisting of loading and unloading of the dumbbell specimen at a constant displacement rate of 50 mm/min. All the tensile testing data were acquired at room temperature.The files named "LOAD_DISP_NAME" contain normalized load vs. displacement data acquired on SENT specimens, as discussed in ref. 1. The load is normalized by the initial area of the uncracked ligament. The files named "R_CURVE_SENT_NAME" contain R-curve data for the SENT specimens. The normalized strain energy is obtained by dividing the strain energy, U, by the initial area of the uncracked ligament. All the fracture testing data were acquired at room temperature.Reference:1. M. Torabizadeh, Z.A. Putnam, M. Sankarasubramanian, J.C. Moosbrugger, S. Krishnan, The effects of initial crack length on fracture characterization of rubbers using the j-integral approach, Polymer Testing, 73 (2019) 327-337
Effect of Mach number on the structure of turbulent spots
No full textDirect numerical simulations have been performed to study the dynamics of isolated turbulent spots in compressible isothermal-wall boundary layers. Results of a bypass transition scenario at Mach 2, 4 and 6 are presented. At all Mach numbers the evolved spots have a leading-edge overhang, followed by a turbulent core and a calmed region at the rear interface. The spots have an upstream-pointing arrowhead shape when visualized by near-wall slices, but a downstream-pointing arrowhead in slices away front the wall. The lateral spreading of the spot decreases substantially with the Mach number, consistent with a growth mechanism based on the instability of lateral shear layers. Evidence for a supersonic (Mach) mode substructure is found in the Mach 6 case, where coherent spanwise structures are observed under the spot overhang region
On the merging of turbulent spots in a supersonic boundary-layer flow
No full textThe complex transition flow physics associated with the merging of turbulent spots in a Mach 2 boundary-layer has been studied using direct numerical simulation. Dynamics of an isolated turbulent spot, merging of laterally displaced spots, and merging of two spots in tandem are considered. The coherent structures associated with the wingtip region of the spot are found to play a major role in destabilising the surrounding laminar fluid. In the merging of laterally displaced spots a strong velocity defect, resulting in unstable inflectional velocity profiles, is observed in the interaction zone. These local inflectional instabilities within the interaction region trigger new large scale coherent structures. During the inline merging, the calmed region behind the tail of the downstream spot is found to suppress the growth of the upstream spot. The upstream spot is ultimately engulfed by the downstream spot
Spark Monitor 0.0.8
No full text<p>Jupyter extension to monitor Apache Spark from notebooks.</p>
<p>Available at:</p>
<p>https://github.com/krishnan-r/sparkmonitor</p>
R&D intensity and market valuation of firm: a study of R&D incurring manufacturing firms in India
No full textThe present study examines the impact of R&D expenditure on market valuation of firm using Tobin’s q. The study uses firm level data for Indian manufacturing sector obtained from Prowess database of CMIE for the period 2001-2010. The study forms an unbalanced panel with 326 R&D incurring (reporting) firms and employs Pooled-OLS and fixed effects models to analyze the relationship between R&D investment and firm value. After controlling some firm specific variables the present study finds an inverted U-shaped relationship between R&D intensity and firm value indicating the diminishing marginal return to each rupee spent on R&D. This finding is consistent with the findings of Huang and Liu (2005) for Taiwan and Bracker and Krishnan (2011) for US. It indicates that, R&D investment have a positive impact on the market value of firm at the beginning, but, when the investment exceeds an optimal level, these investments lower the firm value
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
INTRODUCING HALO - THE DIGITAL (R)EVOLUTION IN MEDICAL TEACHING
No full textAsia Pacific Medical Education Conference 2023285-285Singapor
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Supplementary_material – Supplemental material for Abrupt climate change at ~2800 yr BP evidenced by a stalagmite record from peninsular India
No full textSupplemental material, Supplementary_material for Abrupt climate change at ~2800 yr BP evidenced by a stalagmite record from peninsular India by Nitesh Sinha, Naveen Gandhi, S Chakraborty, R Krishnan, MG Yadava and R Ramesh in The Holocene</p
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