124 research outputs found
Entrepreneurial marketing in subsistence marketplaces
No full textThere are more than a billion poverty-stricken entrepreneurs in the world who run micro-enterprises to meet basic consumption needs. This pervasive phenomenon presents an interesting theoretical conundrum - that of consumer-entrepreneur duality. This duality blurs the boundaries between consumption and entrepreneurship, which have traditionally been distinct domains of scholarly inquiry. The research reported in this dissertation aims to a) provide a theoretical foundation for the notion of consumer-entrepreneur duality and b) test the implications of the aforementioned duality empirically. A key insight flowing from the investigations is that factors in the consumption domain impact important outcomes in the entrepreneurial domain and vice versa.Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2018-05-01The student, Srinivas Venugopal, accepted the attached license on 2016-04-18 at 08:47.The student, Srinivas Venugopal, submitted this Dissertation for approval on 2016-04-18 at 09:04.This Dissertation was approved for publication on 2016-04-19 at 08:14.DSpace SAF Submission Ingestion Package generated from Vireo submission #9286 on 2016-07-07 at 14:17:05Made available in DSpace on 2016-07-07T21:17:37Z (GMT). No. of bitstreams: 4
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Aggregate breakdown of nanoparticulate titania
No full textSix nanosized titanium dioxide powders synthesized from a sulfate process were investigated. The targeted end-use of this powder was for a de-NOx catalyst honeycomb monolith. Alteration of synthesis parameters had resulted principally in differences in soluble ion level and specific surface area of the powders. The goal of this investigation was to understand the role of synthesis parameters in the aggregation behavior of these powders. Investigation via scanning electron microscopy of the powders revealed three different aggregation iterations at specific length scales.
Secondary and higher order aggregate strength was investigated via oscillatory stress rheometry as a means of simulating shear conditions encountered during extrusion. G' and G'' were measured as a function of the applied oscillatory stress. Oscillatory rheometry indicated a strong variation as a function of the sulfate level of the particles in the viscoelastic yield strengths. Powder yield stresses ranged from 3.0 Pa to 24.0 Pa of oscillatory stress. Compaction curves to 750 MPa found strong similarities in extrapolated yield point of stage I and II compaction for each of the powders (at approximately 500 MPa) suggesting that the variation in sulfate was greatest above the primary aggregate level. Scanning electron microscopy of samples at different states of shear in oscillatory rheometry confirmed the variation in the linear elastic region and the viscous flow regime.
A technique of this investigation was to approach aggregation via a novel perspective: aggregates are distinguished as being loose open structures that are highly disordered and stochastic in nature. The methodology used was to investigate the shear stresses required to rupture the various aggregation stages encountered and investigate the attempt to realign the now free-flowing constituents comprising the aggregate into a denser configuration. Mercury porosimetry was utilized to measure the pore size of the compact resulting from compaction via dry pressing and tape casting secondary scale aggregates. Mercury porosimetry of tapes cast at 0.85 and 9.09 cm/sec exhibited pore sizes ranging from 200-500 nm suggesting packing of intact micron-sized primary aggregates. Porosimetry further showed that this peak was absent in pressed pellets corroborating arguments of ruptured primary aggregates during compaction to 750 MPa.Ph.D.Includes bibliographical references (p. 166-170)
Parallelizing Unstructured Sparse Matrix Computations on Large-Scale Multiprocessors
No full textProblems in the class of unstructured sparse matrix computations are characterized by highly irregular dependencies and communication patterns that are not known at compile-time, but can be completely determined at run-time before the computations are actually performed. For this class of problems, current parallelizing compilers are unable to produce efficient code on large-scale distributed memory MIMD multiprocessors, and manual techniques are inflexible and too ad hoc to be generally effective.
In this thesis, we propose a run-time automatic partitioning and scheduling methodology for unstructured sparse matrix computations on large-scale multiprocessors. Our methodology is based on extracting information from the problem instance by preprocessing its symbolic structure, and using this information to achieve high performance in repeated iterations of the computations during which the symbolic structure is unchanged. We present efficient software tools to help users build their parallelization system by following this methodology.
We demonstrate the efficacy of our methodology on sparse Cholesky factorization, which has historically proven to be hard to parallelize. The highlight of our approach is a new two-dimensional block partitioning scheme. We build a run-time parallel system for block sparse Cholesky factorization called Sparse Hybrid Automatic Parallelization Environment (SHAPE), consisting of a parallel partitioner, a parallel scheduler and a parallel communication optimization algorithm. These are modular tools tied together by an explicit representation for block-based unstructured computations. We employ SHAPE to carry out an extensive experimental study of sparse Cholesky factorization on the iPSC/860. The experimental results show that with a judicious choice of partitioning parameters, our block-based partitioning and scheduling method outperforms a well-known column-based method in delivering high performance on a variety of structured and unstructured matrices. The preprocessing itself is shown to be very efficient, its cost being recovered in a small number of iterations of the factorization.
Our methodology and tools may be used to parallelize other unstructured sparse matrix computations for which the same symbolic structure is used in several iterations of the computations. Such computations include sparse triangular solution and sparse
matrix-vector multiplication.Technical report DCS-TR-30
SHAPE: A Parallelization Tool for Sparse Matrix Computations
No full textWe describe the design, implementation and performance of a Sparse Hybrid Automatic Parallelization Environment (SHAPE). SHAPE partitions and schedules sparse matrix computations for Cholesky factorization with the goal of achieving good performance at low cost, while providing flexibility for use as an experimental tool. It employs efficient parallelization algorithms which reduce the communication cost without adversely affecting the load balance by using a hybrid mixture of column and block partitions. Through several parameters, SHAPE aims for portability across a diverse range of sparse matrix structures and message-passing multiprocessors with different communication cost parameters. We present preliminary timing results on the iPSC/860 and compare the performance of SHAPE with that of a commonly used column-based method. The results show that SHAPE significantly reduces computation time, number of messages, and overall communication time for a variety of test matrices.Technical report dcs-tr-29
Supplementation of (Trigonella foenum-graecum L.) Fenugreek Leaves Stimulates the Insulin Action in Streptozotocin- Induced Diabetic Rats
No full textTrigonella foenum-graecum (Fenugreek) leaves exhibit antidiabetic and antioxidant properties. The present study was designed to elucidate the insulin stimulatory effect on supplementation of fenugreek leaves in streptozotocin-induced diabetes in rats. Supplementation of fenugreek leaves mixed with diet at doses of 0.5g and 1.0g/kg of body weight twice daily to diabetic rats for a period of 45days resulted in change in bodyweight, increase in weight of pancreas, enhances the insulin levels and a significant decrease in fasting blood glucose levels. Histopathological observations showed marked changes of the pancreas in treatment with the fenugreek leaves improved the functional state of the pancreatic β-cells and partially retained the damage caused by streptozotocin to the pancreatic islets. These findings of our study clearly indicate the insulin stimulatory effect of fenugreek leaves. The effect observed with the fenugreek leaves was better than that of glibenclamide (600 µg/kg bodyweight). ----------------------------------------------------------------------------------1Reader, Department of Biochemistry, Sathyabama University Dental College and Hospital, Chennai, Tamil Nadu, India2Director of Research, Ex-Dean of Science, Department of Biochemistry and Biotechnology, Annamalai University, Chidambaram*Corresponding author, Email: [email protected], Ph: +91-44- 24503064, Mob: +91-9244488676Cite This Article As:Annida Balakrishnan and Venugopal. P. Menon. 2010. Supplementation of (Trigonella foenum-graecum L.) Fenugreek Leaves Stimulates the Insulin Action in Streptozotocin- Induced Diabetic Rats. J. Ecobiotechnol. 2(3): 26-32
Impacts of physical calibration of a spectral wave model and effects of using different temporal wind inputs
No full textSpectral wave modelling can reduce uncertainties in the estimation of wave energy resource assessment, converter design, extreme value analysis, etc. In spectral models, wave growth is represented with different approaches, resulting in wave resource assessments having large differences especially at high wave values. In this paper a modified version of the North Sea Wave Database is used to quantify the impact of wind temporal fidelity on the wind growth components. The Simulating WAves Nearshore (SWAN) model has been modified, with two different wind inputs used from the European Centre for Medium-Range Weather Forecasts (ECMWF). Results are compared with in-situ measurements an inter-comparison for 20 years (1980-1999). Differences are found on mean and maxima values of wave parameters, with little changes in directionality. However, higher temporal resolution of the wind does not mean always a better hindcast, in fact attention to the calibration of wind-wave growth interactions and whitecaps leads to similar results. Finally, the high fidelity hindcasts are compared, identifying limitations and opportunities for improvements in wave energy assessments.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Offshore Engineerin
The Submerged Floating Tunnel: An experimental study on the hydrodynamics and kinematics of a submerged rectangular cylinder in a wave-current environment
No full textThis study presents the results of small scale flume experiments on a submerged rectangular cylinder subjected to a current, regular wave and combined wave-current environment. The objective of the study is to gain more knowledge about the hydrodynamics around and the kinematics of a submerged structure, to give a contribute to the research field of the submerged floating tunnel. For this study a rectangular cylinder with an aspect ratio (breadth-depth) of 2.5 is used. Two relative submergence depths (flume depth/model submergence) of 2.75 and 1.63 are tested. For all tests a still water depth of 0.7 m is applied. Waves resulting in very low KC numbers of <1 for regular waves and KC[1+U_c/U_m ]<2 for combined waves-current are generated. To create a combined wave-current environment, a current is created in the flume, to which waves are added by the wave generator. The water velocity is measured in front of the model. To approximate the water velocity at the model, a time/phase shift is added to the velocity signal. Linear wave theory is applied to approximate the amplitudes of the orbital velocities at the depth of the model. For the first part of the study, on the hydrodynamic forces, the cylinder is rigidly fixed in the flume. Due to the inertia dominance for low KC numbers, the relationship between the wave parameters and the hydrodynamic forces is well described by the relationship between the wave parameters and the water particle accelerations. The vertical hydrodynamic forces are found to be larger than the horizontal hydrodynamic forces. The force coefficients from this study are compared to coefficient found in previous studies. The drag coefficients for the only current tests agree well with the results from (Courchesne & Laneville, 1979), (Bearman & Trueman, 1972), (Nakaguchi, 1968) and (Venugopal, 2006). For the regular wave and combined wave-current conditions comparable results are found to those by Venugopal for a rectangular cylinder towed through a wave field (Venugopal, 2008). The drag coefficients in the present study show a similar trend in magnitude as in the study by Venugopal. However, the magnitudes have an opposite sign due to the velocity phase shift method applied in the present study. Nevertheless, the effect of this difference on the total force prediction is insignificant, because of inertia dominance. In general, the Morison equation predicts the measured horizontal force well for regular waves. Adding a current component to the waves results in a larger error between the computed Morison forces and the measured force. However, an increase in the magnitude of the added velocity does not lead to a significant increase of this error. The second part of the study focuses on the same cylinder, only not fixed but held in place by 4 tethers. For these tests a buoyancy to weight ratio of 1.5 is applied. The used tested angles between the tethers and the flume bottom are 30˚ and 70 ̊. The water depth, the wave types and model submergence depths are remained equal to the first part of the study. By comparing the kinematics found in three different configurations, a 30˚ tether angle combined with the largest submergence depth of ds=035 m are found to gives the smallest displacements and accelerations. To reduce the kinematics more, it is recommended to add vertical tethers to limit the vertical movement. In general, dynamic features are seen in the tethered model, influencing the magnitude of the kinematics. To predict the magnitude of the tether forces it is recommended to integrated these features in a structural dynamic model.Civil Engineerin
Defects and thermal stability of nanothin Cu films on Mo and Ta
No full textIn situ thermal helium desorption spectrometry (THDS) has been used to characterize defects and thermal stability of nanothin Cu films (0.5-30 nm) deposited on Mo and Ta by electron beam evaporation in ultrahigh vacuum. The substrates used were Mo(110), Mo(100), polycrystalline Mo, Ta(110) and Ta(100). Cu/Mo and Cu/Ta are heteroepitaxial systems, Cu is fcc with a low melting point (1358 K) while Mo and Ta are bcc with high melting points (2890 K and 3287 K respectively). Cu is immiscible in Mo and Ta. Cu/Mo has been used in the superconducting transition-edge microcalorimeters. In the ultralarge-scale integration (ULSI) circuits, Cu is the interconnect material, while Ta is a diffusion barrier candidate. The thermal stability of the Cu seed layers used in Cu interconnection has become an important reliability issue. Helium implanted into the sample after thermalization diffuses interstatially until it encounters a defect where it can be trapped. When the sample is heated, helium is released from the defects at temperatures depending on the helium-defect dissociation energy. In addition, helium can be released when the film undergoes agglomeration and when the film evaporates from the substrate. Defects present in the nanothin Cu films were near surface defects, vacancies, vacancy clusters and defects near the film-substrate interface. Nanothin Cu films on Mo and Ta are metastable at room temperature. On heating the film agglomerates into islands. This transformation is seen as a peak in the helium desorption spectrum. The temperature of agglomeration is strongly dependent on film thickness and substrate surface orientation. The shape and size of the islands is dependent on the substrate surface orientation. Helium-defect interaction in Ta(110) and Ta(100) has also been investigated.Applied Science
Overview of Manufacturing PMC's Using Traditional and 3D printing Technology (FDM)
No full textAbstract: Composite materials are those materials which are made by combining two or more materials with unique properties. Polymer matrix composites are one of the most important composites which are used in various industries due to their light weight, high stiffness and high strength. Because of its advantages it is important to know the manufacturing techniques of PMCs. PMCs are used by automotive, pharmaceutical, sports and aerospace industries. This paper gives detailed review of different traditional and 3d printing methods of manufacturing Polymer Matrix Composites. These methods are more effective in making special shapes west bullet proofs, boat bodies and heavy cylinders. In recent research on effecting manufacturing of composite materials, it is found that the 3d printing technology makes some difference in making PMC with much better properties. In this review we also discuss about one of the 3d printing methods, that is Fusion Deposition Modeling for making PMCs with improved strength and properties.
Keywords: Stiffness, Strength, Polymer Matrix Composite, Manufacturing, FDM, 3d printing.
Title: Overview of Manufacturing PMC’s Using Traditional and 3D printing Technology (FDM)
Author: Eashwaroju Venugopal Chary, G Akshay Kumar
International Journal of Recent Research in Civil and Mechanical Engineering (IJRRCME)
ISSN 2393-8471
Vol. 9, Issue 1, April 2022 - September 2022
Page No: 6-10
Paper Publications
Website: www.paperpublications.org
Published date: 02-July-2022
DOI: https://doi.org/10.5281/zenodo.6790490
Paper Download Link (Source)
https://www.paperpublications.org/upload/book/Overview%20of%20Manufacturing%20PMC’s-02072022-8.pdfInternational Journal of Recent Research in Civil and Mechanical Engineering (IJRRCME), ISSN 2393-8471, Paper Publications, Website: www.paperpublications.or
India’s Macroeconomic Performance and Policies since 2000
No full textThe paper reviews Indias macroeconomic performance and policies since 2000. The first section briefly summarizes key macroeconomic developments regarding economic growth, inflation, external balance, the fiscal situation and aggregate savings and investment. The second section considers some of the challenges posed to macroeconomic management in this period and the efficacy of the policy responses adopted. In particular, it analyses the progress in fiscal consolidation and the policies adopted to deal with the challenge of the unprecedented surge in external capital inflows into India. The final section outlines some of the major macro policy issues that need to be addressed in the years ahead, including : the resurgence of high fiscal deficits; the issues relating to external convertibility and exchange rate management; the role of the Reserve Bank of India in macroeconomic policy and coping with a weak international economic environment.economic growth, inflation, Fiscal Policy, savings and investment, Capital Inflows, exchange rate policy, central bank role
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