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Selected Works

2004

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Articles 1 - 30 of 65

Full-Text Articles in Engineering

Religious Sectarianism: Lessons To Be Learnt From Pakistan, Vikas Kumar Dec 2004

Religious Sectarianism: Lessons To Be Learnt From Pakistan, Vikas Kumar

Vikas Kumar

No abstract provided.


Biomimetic Actuators: Where Technology And Cell Biology Merge [Review Article], Michael Knoblauch, Winfried Peters Nov 2004

Biomimetic Actuators: Where Technology And Cell Biology Merge [Review Article], Michael Knoblauch, Winfried Peters

Winfried S. Peters

The structural and functional analysis of biological macromolecules has reached a level of resolution that allows mechanistic interpretations of molecular action, giving rise to the view of enzymes as molecular machines. This machine analogy is not merely metaphorical, as bio-analogous molecular machines actually are being used as motors in the fields of nanotechnology and robotics. As the borderline between molecular cell biology and technology blurs, developments in the engineering and material sciences become increasingly instructive sources of models and concepts for biologists. In this review, we provide a – necessarily selective – summary of recent progress in the usage of …


A Method Of Minimizing The Power Losses In An Induction Motor With A Squirrel-Cage With Vector, Boukhemis Chetate, Aissa Kheldoun Nov 2004

A Method Of Minimizing The Power Losses In An Induction Motor With A Squirrel-Cage With Vector, Boukhemis Chetate, Aissa Kheldoun

Boukhemis Chetate

No abstract provided.


A Method Of Minimizing The Power Losses In An Induction Motor With A Squirrel-Cage With Vector Control, Boukhemis Chetate, Aissa Kheldoun Nov 2004

A Method Of Minimizing The Power Losses In An Induction Motor With A Squirrel-Cage With Vector Control, Boukhemis Chetate, Aissa Kheldoun

Boukhemis Chetate

An approach to optimizing the flux linkage of the rotor of an induction motor is considered when the motor operates in a vector control mode with indirect orientation in the direction of the field. In this system, the expression for the frequency of the rotor e.m.f. contains the rotor winding impedance; this impedance must therefore be precisely estimated in real time. It is proposed that this should be done using a fuzzy-logic adaptation mechanism. The results of using such a mechanism in a physical model confirm its effectiveness. Key words: induction motor, rotor, vector control, fuzzy logic.


Microzonation Of Earthquake Hazard In Greater Delhi Area, R. N. Iyengar, Susanta Ghosh Nov 2004

Microzonation Of Earthquake Hazard In Greater Delhi Area, R. N. Iyengar, Susanta Ghosh

Susanta Ghosh

spate of earthquakes in the recent past, causing extensive damage, has heightened the sensitivity
of engineers and planners to the looming seismic risk in densely populated Indian cities. Delhi city
is in a seismically active region and hence it is important to understand the existing earthquake hazard
to the city on a scientific basis. This article, after discussing the seismo-tectonic status of the city and
its environs, presents probabilistic seismic hazard analysis of an area of 30 km x 40 km with its
centre at India Gate, Delhi city. The quantified hazard in terms of the rock level peak ground …


Ionic Strength Enhanced Surface Cleaning In Surfactant Solutions, Samuel Morton, D. Keffer, R. Counce Oct 2004

Ionic Strength Enhanced Surface Cleaning In Surfactant Solutions, Samuel Morton, D. Keffer, R. Counce

Samuel A Morton

No abstract provided.


Micro-Bathymetric Mapping Using Acoustic Range Images, Christopher Roman, Hanumant Singh Oct 2004

Micro-Bathymetric Mapping Using Acoustic Range Images, Christopher Roman, Hanumant Singh

Christopher N. Roman

This work focuses on the creation of high resolution micro-bathymetric maps using a high frequency pencil beam sonar. These maps typically cover areas of 10's to 100's of square meters. Data is collected using a sonar mounted to an underwater vehicle that can be positioned at discrete locations on the sea floor or flown in a survey pattern above the bottom. Specifically, we are focused on improving the accuracy of these terrain maps by merging sonar pings taken from multiple vantage points over the same location. This requires the adaption of data registration techniques to handle errors related to the …


Utilizing Green Engineering Concepts In Industrial Conceptual Process Synthesis, Samuel Morton, R. Counce Oct 2004

Utilizing Green Engineering Concepts In Industrial Conceptual Process Synthesis, Samuel Morton, R. Counce

Samuel A Morton

No abstract provided.


Development And Analysis Of A Software Package To Quantify In Vivo Polyethylene Wear After Total Hip Arthroplasty, Allison Kinney, Catherine Ambrose Oct 2004

Development And Analysis Of A Software Package To Quantify In Vivo Polyethylene Wear After Total Hip Arthroplasty, Allison Kinney, Catherine Ambrose

Allison Kinney

Since the first total hip arthroplasty (THA) in 1938, THA evolved and developed into one of the major concentrations of orthopaedic research. The typical hip implant device used today incorporates a femoral and an acetabular component that serve to replicate the anatomical and mechanical functions of the natural hip joint. However, several problems exist that can effect the function of the implant device. Wear in the polyethylene liner of the acetabular component of the total hip replacement device is known as one of the major factors that affects the longevity of total hip replacement devices. Both manual and computer-aided techniques …


The Biggest Experience To Reduce Environmental Pollutants By Substitute Fuel Cng In The Middle East & The Middle Asia, Ali Momeni, Maziar Rostamnezhad, Nader Ale Ebrahim Oct 2004

The Biggest Experience To Reduce Environmental Pollutants By Substitute Fuel Cng In The Middle East & The Middle Asia, Ali Momeni, Maziar Rostamnezhad, Nader Ale Ebrahim

Nader Ale Ebrahim

Automobile industry is an exhaustive industry bringing development for any country. The industrial capabilities needed for development rest in this branch of industry. The Iranian automobile making companies move in line with this aim. But in recent decades, in addition to development of automobile industry, the pollution too has occupied the minds of the authorities of these companies. Some measures, investments, researches, and exhaustive studies related to the pollution problem have been made to produce an automobile of higher technology and lower pollution.


White Light Electrophosphorescence From Polyfluorene-Based Light-Emitting Diodes:€‰ Utilization Of Fluorenone Defects†, Xiong Gong Sep 2004

White Light Electrophosphorescence From Polyfluorene-Based Light-Emitting Diodes:€‰ Utilization Of Fluorenone Defects†, Xiong Gong

Xiong Gong

Poly(9,9-dioctylfluorene-co-fluorenone) with 1% fluorenone, (PFO−F(1%)), was synthesized as a model compound to investigate the optical and electrical effects of fluorenone defects in poly(9,9-dioctylfluoren-2,7-diyl), PFO. Photoluminescence (PL) and electroluminescence (EL) measurements demonstrate that PFO−F(1%) emits stable green light. PL and EL studies indicate that Förster energy transfer to and charge carrier trapping on fluorenone defects (with subsequent fluorenone emission) are responsible for the color degradation typically observed with the polyfluorenes. By utilization of “fluorenone defects” in PFO−fluorenone copolymers (PFO−F), white electrophosphorescent light-emitting diodes were fabricated. Polymer blends were spin-cast from solution containing PFO, PFO−F (1%), and tris[2,5-bis(9,9-dihexylfluoren-2-yl)pyridine-κ2NC3]iridium(III), Ir(HFP)3. The white emission …


Growth Dynamics Of Isotactic Polypropylene Single Crystals During Isothermal Crystallization From A Miscible Polymeric Solvent, Thein Kyu Sep 2004

Growth Dynamics Of Isotactic Polypropylene Single Crystals During Isothermal Crystallization From A Miscible Polymeric Solvent, Thein Kyu

Thein Kyu

The present article presents a spatiotemporal growth of isotactic polypropylene (iPP) single crystals, melt crystallized from a polymeric solvent, i.e., poly (ethylene octene) copolymer that is known to be miscible with iPP. Optical and atomic force microscopic investigations reveal that the melt grown single crystals of iPP develop in the form of two parallel rows of crystal lamellae, but these crystals merge at the tips. To elucidate the mechanism of these emerging parallel rows of iPP crystals, a phase field model pertaining to solidification phenomena has been employed that involves a nonconserved crystal order parameter and a chain-tilting angle. This …


Knowledge Discovery From Multispectral Satellite Images, Arun D. Kulkarni Sep 2004

Knowledge Discovery From Multispectral Satellite Images, Arun D. Kulkarni

Arun Kulkarni

A new approach to extract knowledge from multispectral images is suggested. We describe a method to extract and optimize classification rules using fuzzy neural networks (FNNs). The FNNs consist of two stages. The first stage represents a fuzzifier block, and the second stage represents the inference engine. After training, classification rules are extracted by backtracking along the weighted paths through the FNN. The extracted rules are then optimized by use of a fuzzy associate memory bank. We use the algorithm to extract classification rules from a multispectral image obtained with a Landsat Thematic Mapper sensor. The scene represents the Mississippi …


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 …


A System Engineering Approach To The Design Of Asynchronous Online Systems Engineering Courses, M. Pennotti, Caroline Lubert, D Verma Aug 2004

A System Engineering Approach To The Design Of Asynchronous Online Systems Engineering Courses, M. Pennotti, Caroline Lubert, D Verma

Caroline P Lubert

No abstract provided.


How A Mirage Is Formed, Christopher Roman Aug 2004

How A Mirage Is Formed, Christopher Roman

Christopher N. Roman

Article that appeared in Sail magazine (ISSN: 0036-2700).


Planning Evaluation Of Radiotherapy For Complex Lung Cancer Cases Using Helical Tomotherapy, Tomas Kron, Grigor Grigorov, Edward Yu, Slav Yartsev, Jeff Chen, Eugene Wong, George Rodrigues, Kris Trenka, Terry Coad, Glenn Bauman, Jake Van Dyk Aug 2004

Planning Evaluation Of Radiotherapy For Complex Lung Cancer Cases Using Helical Tomotherapy, Tomas Kron, Grigor Grigorov, Edward Yu, Slav Yartsev, Jeff Chen, Eugene Wong, George Rodrigues, Kris Trenka, Terry Coad, Glenn Bauman, Jake Van Dyk

Edward Yu

Lung cancer treatment is one of the most challenging fields in radiotherapy. The aim of the present study was to investigate what role helical tomotherapy (HT), a novel approach to the delivery of highly conformal dose distributions using intensity-modulated radiation fan beams, can play in difficult cases with large target volumes typical for many of these patients. Tomotherapy plans were developed for 15 patients with stage III inoperable non-small-cell lung cancer. While not necessarily clinically indicated, elective nodal irradiation was included for all cases to create the most challenging scenarios with large target volumes. A 2 cm margin was used …


Investigation Of Weight Reuse In Multi-Layer Perceptron Networks Foraccelerating The Solution Of Differential Equations, Kevin Mcfall, J. R. Mahan Jul 2004

Investigation Of Weight Reuse In Multi-Layer Perceptron Networks Foraccelerating The Solution Of Differential Equations, Kevin Mcfall, J. R. Mahan

Kevin McFall

Research has shown that training multi-layer perceptron networks to solve ordinary and partial differential
equations (DEs) can be accelerated by reusing network weights from a previously solved similar problem. This paper compares weight reuse for two existing methods of defining the network error function. Weight reuse is shown to accelerate training of one ordinary and two partial DEs even for equations with significantly different parameters or boundary/initial conditions. The second method outperforms the first for partial DEs where multiple boundary/initial conditions are defined, but fails unpredictably when weight reuse is applied to accelerate solution of the diffusion equation.


Multidimensional Digital Signal Estimation Using Kalman's Theory For Computer-Aided Applications, Ivan E. Villalon-Turrubiates, Jose A. Andrade-Lucio, Oscar G. Ibarra-Manzano Jul 2004

Multidimensional Digital Signal Estimation Using Kalman's Theory For Computer-Aided Applications, Ivan E. Villalon-Turrubiates, Jose A. Andrade-Lucio, Oscar G. Ibarra-Manzano

Iván Esteban Villalón Turrubiates

In this paper, we analyze the Multidimensional Kalman Algorithm to estimate a signal corrupted by white Gaussian noise. Because the theory provide a good solution to the problem with a large number of signals, we developed an algorithm for three-dimensional Kalman filtering applied to the positioning problem (latitude, altitude and longitude) of a stationary object based on GPS signals. This application was selected because the incoming signals of the GPS encounters some noise on its way to the receiver, which is originated from different types of sources, the consequences are that the received signals are noisy, therefore inaccurate. The signals …


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.


Experimental Studies Of Generalized Neuron Based Power System Stabilizer, D. K. Chaturvedi, O. P. Malik, P. K. Kalra Jul 2004

Experimental Studies Of Generalized Neuron Based Power System Stabilizer, D. K. Chaturvedi, O. P. Malik, P. K. Kalra

D. K. Chaturvedi Dr.

Artificial neural networks (ANNs) can be used as intelligent controllers to control nonlinear, dynamic systems through learning, which can easily accommodate the nonlinearities and time dependencies. However, they require large training time and large number of neurons to deal with complex problems. To overcome these drawbacks, a generalized neuron (GN) has been developed that requires much smaller training data and shorter training time. Taking benefit of these characteristics of the GN, a new power system stabilizer (PSS) is proposed. Results show that the proposed GN-based PSS can provide a consistently good dynamic performance of the system over a wide range …


Grandmother’S Syncretic Hinduism Caught In The Whirlwind Of Vhp’S Sectarianism, Vikas Kumar Jul 2004

Grandmother’S Syncretic Hinduism Caught In The Whirlwind Of Vhp’S Sectarianism, Vikas Kumar

Vikas Kumar

No abstract provided.


Does Active Learning Work? A Review Of The Research, Michael Prince Jun 2004

Does Active Learning Work? A Review Of The Research, Michael Prince

Michael J. Prince

No abstract provided.


Wind Shear, Christopher Roman Jun 2004

Wind Shear, Christopher Roman

Christopher N. Roman

Article that appeared in Sail magazine (ISSN: 0036-2700).


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 …


Optimization Of Protocrystalline Silicon P-Type Layers For Amorphous Silicon N-I-P Solar Cells, G. M. Ferreira, Chi Chen, R. J. Koval, Joshua M. Pearce, C. R. Wronski, R. W. Collins May 2004

Optimization Of Protocrystalline Silicon P-Type Layers For Amorphous Silicon N-I-P Solar Cells, G. M. Ferreira, Chi Chen, R. J. Koval, Joshua M. Pearce, C. R. Wronski, R. W. Collins

Joshua M. Pearce

Real time spectroscopic ellipsometry has been applied to develop deposition phase diagrams for p-type hydrogenated silicon (Si:H) films prepared at low temperature (200 °C) by rf plasma-enhanced chemical vapor deposition using gas mixtures of SiH4, H2, and BF3. These diagrams depict the regimes of accumulated thickness and H2-dilution ratio R=[H2]/[SiH4] within which p-type amorphous Si:H [a-Si:H], mixed-phase Si:H [(a + μc)-Si:H], and single-phase microcrystalline Si:H [μc-Si:H] films are obtained in depositions on R=0 a-Si:H surfaces. The performance of n–i–p solar cells incorporating p-layers deposited under the same conditions as those used in the phase diagram development has been correlated with …


The Technical Requirements For Multichannel Qam Rf Modulators, Ron D. Katznelson May 2004

The Technical Requirements For Multichannel Qam Rf Modulators, Ron D. Katznelson

Ron D. Katznelson

This paper addresses the technical requirements and implications for multichannel QAM RF modulators and upconverters and the factors that affect their proposed RF specifications. RF output power levels per channel, adjacent channel noise and broadband noise levels of such a class of multichannel modulators will be discussed. A spectral noise specification mask that is equivalent to that obtained from a combination of multiple identical masks of a standard single channel noise specifications based on power addition will be presented. The power back-off required for maintaining the proposed distortion mask levels as a function of the number of adjacent channels supported …


Standard-Deviation Minimization For Calibrating The Radii Of Spheres Attached To Atomic Force Microscope Cantilevers, Nancy Burnham, E Thoreson Apr 2004

Standard-Deviation Minimization For Calibrating The Radii Of Spheres Attached To Atomic Force Microscope Cantilevers, Nancy Burnham, E Thoreson

Nancy A. Burnham

We describe an efficient method for determining the radii of spheres attached to atomic force microscope(AFM) cantilevers by minimizing the square root of the square error for a segment of circular arc cross-sectional data. The approach we present has benefits: (1) The method fits a function, with two fitting parameters, to a number of data points, rather than calculating the radius based on two points of cross-sectional data, (2) a fit is performed in a common spreadsheet application, using a solving feature, and (3) spheres of diameters 2 to 60 μm were measured to an accuracy of 9% and a …


What Makes The Trades?, Christopher Roman Apr 2004

What Makes The Trades?, Christopher Roman

Christopher N. Roman

Article that appeared in Sail magazine (ISSN: 0036-2700).