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Asymptotic Accuracy Of Geoacoustic Inversions, Michele Zanolin, Ian Ingram, Aaron Thode, Nicholas C. Makris Sep 2004

Asymptotic Accuracy Of Geoacoustic Inversions, Michele Zanolin, Ian Ingram, Aaron Thode, Nicholas C. Makris

Michele Zanolin

Criteria necessary to accurately estimate a set of unknown geoacoustic parameters from remote acoustic measurements are developed in order to aid the design of geoacoustic experiments. The approach is to have estimation error fall within a specified design threshold by adjusting controllable quantities such as experimental sample size or signal-to-noise ratio (SNR). This is done by computing conditions on sample size and SNR necessary for any estimate to have a variance that (1) asymptotically attains the Cramer–Rao lower bound (CRLB) and (2) has a CRLB that falls within the specified design error threshold. Applications to narrow band deterministic signals received …


Dual-Pump Dual-Broadband Coherent Anti-Stokes Raman Scattering In Reacting Flows, Sukesh Roy, Terrence R. Meyer, Robert P. Lucht, Mikael Afzelius, Per-Erik Bengtsson, James R. Gord Jul 2004

Dual-Pump Dual-Broadband Coherent Anti-Stokes Raman Scattering In Reacting Flows, Sukesh Roy, Terrence R. Meyer, Robert P. Lucht, Mikael Afzelius, Per-Erik Bengtsson, James R. Gord

Terrence R Meyer

A dual-pump, dual-broadband coherent anti-Stokes Raman scattering system for simultaneous measurements of temperature and concentrations of N2, O2, and CO2 in reacting f lows is demonstrated. In this system pure rotational transitions of N2 O2 and rovibrational transitions of N2 CO2 are probed simultaneously with two narrowband pump beams, a broadband pump beam, and a broadband Stokes beam. The main advantage of this technique is that it permits accurate temperature measurements at both low and high temperatures as well as concentration measurements of three molecules.


Velocity Effects On The Wear, Friction And Tribochemistry Of Aluminum Mmc Sliding Against Phenolic Brake Pad May 2004

Velocity Effects On The Wear, Friction And Tribochemistry Of Aluminum Mmc Sliding Against Phenolic Brake Pad

A.S. Md Abdul Haseeb

Two aluminum metal matrix composites (MMC) reinforced with 13 vol.% of SiC or B4C particles were made by stir casting followed by hot extrusion. Effects of sliding velocity on the wear, friction and tribochemistry of the worn surfaces of both composites sliding against a commercial phenolic brake pad have been investigated under dry condition. The wear tests were carried out using a pin-on-disc type apparatus at two linear sliding speeds: 1.62 and 4.17 m s-1 under a constant contact pressure of 0.75 MPa for a sliding distance of 5832 m. The coefficient of friction was recorded and wear rate of …


Food Based Approaches For A Healthy Nutrition In Africa, Mamoudou Hama Dicko May 2004

Food Based Approaches For A Healthy Nutrition In Africa, Mamoudou Hama Dicko

Pr. Mamoudou H. DICKO, PhD

The latest estimates of the FAO demonstrate the problems of the fight against hunger. These problems are manifested by the ever-increasing number of chronically undernourished people worldwide. Their numbers during the 1999-2001 period were estimated at about 840 million of which 798 million live in developing countries. Sub-Saharan Africa alone represented 198 million of those. In this part of Africa the prevalence of undernourishment ranges from 5-34%, causing growth retardation and insufficient weight gain among one third of the children under five years of age and resulting in a mortality of 5-15% among these children. Malnutrition resulting from undernourishment is …


Three-Dimensional Simulations Of Self-Assembly Of Hut Shaped Si-Ge Quantum Dots, Ashwin Ramasubramaniam, V. B. Shenoy Dec 2003

Three-Dimensional Simulations Of Self-Assembly Of Hut Shaped Si-Ge Quantum Dots, Ashwin Ramasubramaniam, V. B. Shenoy

Ashwin Ramasubramaniam

This article presents the results of three-dimensional modeling of heteroepitaxial thin film growth with the objective of understanding recent experiments on the early stages of quantum dot formation in SiGe/Si systems. We use a continuum model, based on the underlying physics of crystallographic surface steps, to study the growth of quantum dots, their spatial ordering and coarsening behavior. Using appropriate parameters, obtained from atomistic calculations, the (100) orientation is found to be unstable under compressive strains. The surface energy now develops a minimum at an orientation that may be interpreted as the (105) facet observed in SiGe/Si systems. This form …