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2006

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Articles 1 - 30 of 3617

Full-Text Articles in Engineering

Upper Extremity Dynamics During Lofstrand Crutch-Assisted Gait In Children With Myelomeningocele, Brooke A. Slavens, Jamie Frantz, Peter F. Sturm, Gerald F. Harris Dec 2006

Upper Extremity Dynamics During Lofstrand Crutch-Assisted Gait In Children With Myelomeningocele, Brooke A. Slavens, Jamie Frantz, Peter F. Sturm, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Background/Objective:

We present a 3-dimensional biomechanical model of the upper extremities to characterize joint dynamics during 2 patterns of Lofstrand crutch-assisted gait in children with myelomeningocele. The upper extremity model incorporates recommendations by the International Society of Biomechanics.

Methods:

A Vicon motion analysis system (14 cameras) captured the marker patterns. Instrumented crutches measured reaction forces. Five subjects with L3 or L4 level myelodysplasia (aged 9.8 ± 1.6 years) were analyzed during reciprocal and swing-through Lofstrand crutch-assisted gait.

Results:

The mean walking speed, cadence, and stride length were greatest during swing-through gait. Although the gait patterns had different morphologies ...


Hydrodynamics Investigation Of In-Vitro Dissolution Testing, Ge Bai Dec 2006

Hydrodynamics Investigation Of In-Vitro Dissolution Testing, Ge Bai

Dissertations

Dissolution testing is routinely carried out in the pharmaceutical industry to determine dissolution rate of solid dosage forms. The United States Pharmacopoeia (USP) Dissolution Apparatus II is the device most commonly used for this purpose. Despite its widespread use, dissolution testing remains susceptible to significant error and test failures. Limited information is available on the hydrodynamics of this apparatus, although hydrodynamic effects can play a major role on test performance.

Laser-Doppler Velocimetry (LDV) and Computational Fluid Dynamics (CFD) were used here to experimentally map and computationally predict the velocity distribution inside a standard USP Apparatus II under the typical operating ...


Some Contributions On Mimo Radar, Nikolaus Lehmann Dec 2006

Some Contributions On Mimo Radar, Nikolaus Lehmann

Dissertations

Motivated by recent advances in Multiple Input Multiple Output (MIMO) wireless communications, this dissertation aims at exploring the potential of MIMO approaches in the radar context. In communications, MIMO systems combat the fading effects of the multi-path channel with spatial diversity. Further, the scattering environment can be used by such systems to achieve spatial multiplexing. In radar, a complex target consisting of several scatterers takes the place of the multi-path channel of the communication problem. A target's radar cross section (RCS), which determines the amount of returned power, greatly varies with the considered aspect. Those variations significantly impair the ...


Investigation Of Formation And Applications Of High-Speed Liquid Projectiles, Oleg Petrenko Dec 2006

Investigation Of Formation And Applications Of High-Speed Liquid Projectiles, Oleg Petrenko

Dissertations

The work comprises experimental and numerical studies of generation and application of high-speed liquid projectiles. Numerical models were created for a projectile formation by two kinds of launchers, water extruder and water cannon. In the water extruder the kinetic energy of a fast moving piston is transferred to the water load and extrudes the load at a high speed. By contrast in the water cannon the water load itself accumulates the kinetic energy from the expanding combustion gasses. Then, in the course of water motion through the converging nozzle the energy is redistributed between head and tail of the projectile ...


Enhancement Of Fluidization And Filtration Using Nanoparticle Agglomerates And Aerogels, Jose A. Quevedo Dec 2006

Enhancement Of Fluidization And Filtration Using Nanoparticle Agglomerates And Aerogels, Jose A. Quevedo

Dissertations

Previous works have classified the fluidization behavior of nanoparticles as Agglomerate Particulate Fluidization (APF) and Agglomerate Bubbling Fluidization (ABE). These fluidization behaviors are quite different in regard to the fluidized bed expansion, the presence of bubbles and the smoothness of the bed surface, with APF nanopowders showing a much more homogeneous fluidization and a much better dispersion than ABE nanopowders which are generally very difficult to fluidize and show vigorous bubbling. In the present work, the fluidization of APF as well as ABF nanopowders is studied in depth, both conventionally, and in the presence of extemal assistance; several related topics ...


Flow Characteristics And Phase Interactions Of Evaporating Sprays In Gas-Solid Suspensions, Muhammad Mushahid Rafique Qureshi Dec 2006

Flow Characteristics And Phase Interactions Of Evaporating Sprays In Gas-Solid Suspensions, Muhammad Mushahid Rafique Qureshi

Dissertations

Evaporating spray jets have a wide range of applications in many industrial processes such as fluidized catalytic cracking of crude oil in petroleum refinery, coal gasification, fluidized coking to make synthetic crude oil, and condensed mode gas polymerization. The rapid evaporation of spray jets significantly affects the gas-solids mixing, solids concentration, gas/solids temperature and gas/solids velocity acceleration. The complex interactions mechanism of phase change, three phase interaction, heat and mass transfer of gas, solids and evaporating droplets dominate the process efficiency and product quality. In such three-phase flows, the phase transport characteristics are influenced by both droplet-gas interaction ...


Doppler Spread Estimation In Mobile Fading Channels, Hong Zhang Dec 2006

Doppler Spread Estimation In Mobile Fading Channels, Hong Zhang

Dissertations

The Doppler spread, or equivalently, the mobile speed, is a measure of the spectral dispersion of a mobile fading channel. Accurate estimation of the mobile speed is important in wireless mobile applications which require such as knowledge of the rate of channel variations. In this dissertation, first the performance of classical crossing- and covariance-based speed estimators is studied. Next, the problem of mobile speed estimation using diversity combining is investigated. Then, a nonparametric estimation technique is proposed that is robust to different channel variations. Finally, cyclostationarity-based speed estimators which can be applied either blindly or with the aid of pilot ...


Afci Quarterly Input: Unlv October 1 Through December 31, 2006, Harry Reid Center For Environmental Studies. Nuclear Science And Technology Division Dec 2006

Afci Quarterly Input: Unlv October 1 Through December 31, 2006, Harry Reid Center For Environmental Studies. Nuclear Science And Technology Division

Transmutation Research Program Reports (TRP)

Quarterly report highlighting research projects, activities and objectives of the Transmutation Research Program at the Nuclear Science & Technology Division, Harry Reid Research Center.

The University of Nevada, Las Vegas supports the AFCI through research and development of technologies for economic and environmentally sound refinement of spent nuclear fuel. The UNLV program has four components: infrastructure, international collaboration, student-based research, and management and program support.


Nanoparticle Formation And Coating Using Supercritical Fluids, Abhijit Aniruddha Gokhale Dec 2006

Nanoparticle Formation And Coating Using Supercritical Fluids, Abhijit Aniruddha Gokhale

Dissertations

Jet breakup phenomenon and nanoparticle formation

The focus of this dissertation is to study the SAS process to manufacture nanoparticles with minimum agglomeration, controlled size and size distribution. Solution jet breakup and solvent evaporation into supercritical fluid (SC CO2) is studied using high speed charged coupled device (CCD) camera facilitated with double shot particle image veloimetry (PIV) laser and a high pressure view cell. Particles formation using SAS is studied. Polyvinylpyrrolidone (PVP) particles are formed using micron size capillary nozzles and combination of thermodynamically good and poor solvents in order to achieve nano-sized particles with reduced agglomeration and narrow ...


Reactive Modification And Crystallization Behavior Of Foamed Poly(Butylene Terephthalate), Byeong Joon Jeong Dec 2006

Reactive Modification And Crystallization Behavior Of Foamed Poly(Butylene Terephthalate), Byeong Joon Jeong

Dissertations

The objective of this study is to investigate the feasibility of preparing low density foams based on poly(butylene terephthalate) (PBT) through modification of its molecular structure and rheological characteristics by reactive extrusion. The scientific and/or engineering interpretation of the experimental data was based on fundamentals of extrusion, crystallization mechanisms, as well as information on reactivity and tendency toward degradation of PBT.

As a preliminary study, the extrusion foaming behavior of a commercial linear semi-crystalline PBT with a chemical blowing agent (CBA) was investigated. Foam characteristics were functions of extrusion operational variables, such as die set temperature and screw ...


Solvent Resistant Microporous/Nanoporous Polymeric Hollow Fiber And Flat Film Membranes And Their Applications, Praveen B. Kosaraju Dec 2006

Solvent Resistant Microporous/Nanoporous Polymeric Hollow Fiber And Flat Film Membranes And Their Applications, Praveen B. Kosaraju

Dissertations

The separation and purification of organic-solvent-based process streams may be carried out by membrane processes such as nanofiltration/ultrafiltration/microfiltration and membrane solvent extraction. Lack of solvent stability and chemical stability of most commercially available membranes is limiting the utilization of the above mentioned membrane technologies. This dissertation was primarily focused on developing solvent resistant hollow fiber and flat film membranes for separation and purification of organic-solvent-based process streams.

Available porous polymeric supports (Polypropylene (PP), Polyethersulfone (PES) and Nylon) suitable for the required solvent-stable applications were chosen first and then the supports were modified to satisfy the requirements for the ...


Multi-Degree Of Freedom Telemanipulation In An Unstructured Environment, Diego Ramirez Dec 2006

Multi-Degree Of Freedom Telemanipulation In An Unstructured Environment, Diego Ramirez

Theses

Two approaches to 6-degrees-of-freedom telemanipulation that will accommodate different needs and skills of potential users with congenital amputation, arthrogryposis, muscular dystrophy and cerebral palsy were developed. One method uses scalable movements (i.e. position and orientation), and the second employs isometric forces and torques without movement. The scalable position approach employs a 6-degress-of-freedom electromechanical stylus whose joint orientations are used by the controlling computer to determine the position and orientation of the robot's end effector via inverse kinematics or by one-to-one matching of the stylus joint angles with those of the manipulator. The isometric method uses the measured forces ...


Solubility In Supercritical Carbon Dioxide, Syed Asif Abdullah Dec 2006

Solubility In Supercritical Carbon Dioxide, Syed Asif Abdullah

Theses

The different techniques used for the determination of the solubility of compounds in supercritical carbon dioxide are described. A comparative study is made of the methods used in the measurement of the concentration of benzoic acid and caffeine in supercritical carbon dioxide. The difference in measurement techniques did not have much effect on the solubility data at lower pressures. However, at higher pressures, the solubility data obtained by different techniques began to deviate from each other.

Further, the method used by different researchers in generating the solubility data in supercritical carbon dioxide is also discussed. A number of data sheets ...


Numerical Analysis Of The Operation Of A Water Cannon, Teymuraz G. Bitadze Dec 2006

Numerical Analysis Of The Operation Of A Water Cannon, Teymuraz G. Bitadze

Theses

This study was designed to investigate the operational process of a launcher for generation of high speed water projectiles, and it involved the optimization of the geometry of a launcher body. The objective of the optimization of the internal geometry was to increase the effective momentum of the projectile while the optimization of the external geometry resulted in the reduction of the mass of the launcher.

In the course of the optimization of the internal geometry the exit velocity variation was determined, and used to compute an effective projectile momentum, which actually affects a workpiece. In this research, it was ...


Channel-Predictive Link Layer Arq Protocols In Wireless Networks, Huseyin Dogukan Cavdar Dec 2006

Channel-Predictive Link Layer Arq Protocols In Wireless Networks, Huseyin Dogukan Cavdar

Theses

Communication performance over a wireless channel should be considered according to two main parameters: energy and throughput. The reliable data transfer is a key to these goals. The reliable node-to-node data transfer is performed by link layer protocols. One prominent approach is Automatic Repeat Request (ARQ) protocol. The traditional ARQ protocols attempt to recover the erroneously transmitted frames by retransmitting those frames, regardless of the channel state. Since this channel state unaware behaviour may cause unnecessary retransmissions, traditional ARQ protocols are expected to be energy inefficient. Some ideas have been proposed such as stochastic learning automaton based ARQ, and channel ...


A Dynamic Supine Stander For Subjects With Disabilities Leading To Prolonged Immobility, Luis Alberto Espina Dec 2006

A Dynamic Supine Stander For Subjects With Disabilities Leading To Prolonged Immobility, Luis Alberto Espina

Theses

Bone tissue needs to be exposed to loading in order to stimulate the osteogenic response of the body. Disabilities that lead to prolonged immobility will result in a decrease of the osteogenic processes and an increase in resorption of bone by osteoclast cells. This disuse modeling can lead to osteopenia, osteoporosis, and subsequent non-traumatic fractures. These disabilities are varied in nature and duration, and can include load bearing bone fracture, excessive obesity, spinal cord injury, and cerebral palsy.

The following describes the concept and design of a novel dynamic supine stander that will provide loads simulating ambulation to the lower ...


Functionalization Of Nanoclays Through Exchange Reactions, Jin Uk Ha Dec 2006

Functionalization Of Nanoclays Through Exchange Reactions, Jin Uk Ha

Theses

A cationic clay (sodium-montmorillonite, MMT) and an anionic clay (hydrotalcite, HT) were treated with two phosphonium based ionic liquids (ILs) and a commercial corrosion inhibitor. Clay modification was examined by TGA, FTLR and WXRD. The cationic clay modified with both ILs had similar thermal stabilities since they contained the same cation although the original anions were different. The thermal stability of the modified clays was higher than that of a commercial organoclay and of clays modified in our group with smaller MW pyridinium and imidazolium based cations. 10 wt% of interchanged cation was found under selected time/temperature treatment conditions ...


A Kinematic Analysis Of Sign Language, Chemuttaai C. Koech Dec 2006

A Kinematic Analysis Of Sign Language, Chemuttaai C. Koech

Theses

Signed languages develop among deaf populations and employ manual communication instead of voiced communication. Stokoe attributes classify individual signs in American Sign Language (ASL) and include handshape, hand location, movement, orientation, and facial expression. Signed and oral languages are not mutually understood, and many deaf individuals live in linguistic isolation. This research addresses computer translation between signing and speech, investigating sign duration in sentence context versus in isolation and identifying kinematic sign markers. To date, there has been little study of continuous signing kinematics; it was previously unknown if kinematic markers existed.

Kinematic data were collected from a proficient signer ...


Burmester Curve And Numerical Motion Generation Of Grashof Mechanisms With Perimeter And Transmission Angle Optimization In Mathcad, Peter J. Martin Dec 2006

Burmester Curve And Numerical Motion Generation Of Grashof Mechanisms With Perimeter And Transmission Angle Optimization In Mathcad, Peter J. Martin

Theses

An infinite number of planar four-bar mechanism solutions exist for a series of prescribed rigid-body positions. Given a set of Burmester curves or numerically-generated fixed and moving pivot curves, sorting through the limitless number of possible mechanism solutions to find one that ensures full link rotatibility, satisfies compactness criteria and produces feasible transmission angles can be a daunting task. In this work, two algorithms are developed and presented by which the user can select optimum planar four-bar motion generators (optimum with respect to Grashof criteria, mechanism perimeter criteria and transmission angle criteria) from a set of all mechanism solutions produced ...


Jet Assisted Fluidization Of Nanoparticle Agglomerates, Ayokunle O. Omosebi Dec 2006

Jet Assisted Fluidization Of Nanoparticle Agglomerates, Ayokunle O. Omosebi

Theses

Fluidization serves as a primary operation used to disperse, handle and process nanoparticles, but due to the complications involved with achieving homogenous fluidization of the agglomerates of nanoparticles, several methods have been developed to assist their conventional mode of fluidization.

In this work, the conventional mode of fluidization was coupled with secondary gas flow emerging from a micro jet nozzle. The effect of the jet on the fluidization behavior of various APF and ABF nanopowders was studied and compared with the pure conventional fluidization mode. Generally, experiments were conducted to find the optimal operation of the jet by varying parameters ...


Inverse Solid-Liquid Fluidization Of Aerogel Granules And Its Application In Removing Oil From Water, Gaurav Babubhai Patel Dec 2006

Inverse Solid-Liquid Fluidization Of Aerogel Granules And Its Application In Removing Oil From Water, Gaurav Babubhai Patel

Theses

Fluidization is a very well known unit operation used in the chemical industry for various purposes. Inverse solid-liquid fluidization, where the solid particles to be fluidized are less dense than the fluid, is one of the several different kinds of fluidization being studied for its potential in industrial applications. The present work focuses on finding the hydrodynamic characteristics (minimum fluidization velocity, bed expansion and pressure drop) of an inverse fluidized bed of aerogel granules and using this system to remove oil from an oil-water mixture. The solid particles employed for this study are low density (100 kg/m3) surface ...


Implementation Of Stereo Correspondence Algorithms For Multi-Baseline Vision System, Navaneetha Shivram Dec 2006

Implementation Of Stereo Correspondence Algorithms For Multi-Baseline Vision System, Navaneetha Shivram

Theses

The purpose of this study is to determine the impact of varying camera baselines on correspondence and depth estimation. As the baseline increases the resolution of depth increases but finding correspondences is very tedious. On the other hand when cameras are placed close to each other and thereby reducing the baseline distance points in the images are easily matched however depth resolution deteriorates. This problem is solved by using a multi-camera system is used in which the cameras are spaced close to each other along a straight line. Calculating the correspondence along successive camera pairs is relatively easy. These respondences ...


Non-Repudiation Secure File Transfer Protocol (Nrsftp), Jerry Chen Dec 2006

Non-Repudiation Secure File Transfer Protocol (Nrsftp), Jerry Chen

Theses

Non Repudiation Secure File Transfer Protocol (NRSFTP) is designed to resolve three main concerns for today's electronic file transfer methodology. The three main concerns are Non-Repudiation, Secure, and Non-Real Time file transfer. Non-repudiation is to assure the receiver that the sender of the document is not an imposter. Secure document transfer is to assure the sender that only the intended receiver will be able to read the document. Non-real-time file transfer is to provide convenient and low cost transportability of the encrypted data from one party to another. With the above three concerns addressed, the NRSFTP protocol can be ...


Boosted Ensemble Algorithm Strategically Trained For The Incremental Learning Of Unbalanced Data, Michael David Muhlbaier Dec 2006

Boosted Ensemble Algorithm Strategically Trained For The Incremental Learning Of Unbalanced Data, Michael David Muhlbaier

Theses and Dissertations

Many pattern classification problems require a solution that needs to be incrementally updated over a period of time. Incremental learning problems are often complicated by the appearance of new concept classes and unbalanced cardinality in training data. The purpose of this research is to develop an algorithm capable of incrementally learning from severely unbalanced data. This work introduces three novel ensemble based algorithms derived from the incremental learning algorithm, Learn++. Learn++.NC is designed specifically for incrementally learning New Classes through dynamically adjusting the combination weights of the classifiers' decisions. Learn++.UD handles Unbalanced Data through ...


Inverse Dynamic Modeling For Characterization Of Spasticity, Katharine Markel Swift Dec 2006

Inverse Dynamic Modeling For Characterization Of Spasticity, Katharine Markel Swift

Theses

Spasticity affects subjects with cerebral palsy, stroke, multiple sclerosis, and traumatic brain injury. The need to develop a deeper understanding of spasticity is driven by the existing limited understanding and the lack of satisfactory interventions for this disabling phenomenon.

An inverse model is implemented to describe the motion in the pendulum knee drop test. Inverse kinematic modeling is implemented to investigate the pathophysiology of spasticity.

Using the equilibrium point hypothesis as a conceptual framework to explain disabled and non-disabled neuromuscular control, it has been demonstrated that the equilibrium point of the passive knee is dynamic and exhibits a pseudo-exponential trajectory ...


Determining Continual Improvement Process Methods Within Quality Management Systems, Diane M. Bové Dec 2006

Determining Continual Improvement Process Methods Within Quality Management Systems, Diane M. Bové

Theses

Institutionalized standards require organizations to actively define and implement quality management systems, which includes active participation in continual improvement efforts. Interpretations and practices vary on implementation methodology.

Traditional views of quality do not integrate the technical disciplines into a defined science which would support a standardized approach for continual improvement implementation.

In order to optimize improvement efforts, a conceptual hypothesis is proposed to integrate quality through combining and collaborating implementation efforts of engineering, control, assurance, improvement and costs. The purpose of this thesis is to establish a roadmap to assist in choosing effective quality improvement methodologies and toolsets that assist ...


Multiresolution Wavelet Analysis Of Event-Related Eeg Potentials Using Ensemble Of Classifier Data Fusion Techniques For Early Diagnosis Of Alzheimer's Disease, Apostolos Topalis Dec 2006

Multiresolution Wavelet Analysis Of Event-Related Eeg Potentials Using Ensemble Of Classifier Data Fusion Techniques For Early Diagnosis Of Alzheimer's Disease, Apostolos Topalis

Theses and Dissertations

The recent advances and knowledge in medicine and nutrition have greatly improved our average life expectancy. An unfortunate consequence of this longer life span, however, is a dramatic increase in the number of individuals suffering from dementia, and more specifically, from Alzheimer's disease (AD). Furthermore, AD remains under-diagnosed and under-treated until its more severe stages due to lack of standard diagnostic tools available to community clinics. A search for biomarkers that will allow early diagnosis of the disease is therefore necessary to develop effective medical treatments. Such a biomarker should be non-invasive, simple to obtain, safe, inexpensive, accurate, and ...


An Architecture For Intelligent Health Assessment Enabled Ieee 1451 Compliant Smart Sensors, Donald Albert Nickles Dec 2006

An Architecture For Intelligent Health Assessment Enabled Ieee 1451 Compliant Smart Sensors, Donald Albert Nickles

Theses and Dissertations

As systems become increasingly complex and costly, potential failure mechanisms and indicators are numerous and difficult to identify, while the cost of loss is very expensive - human lives, replacement units, and impacts to national security. In order to ensure the safety and long-term reliability of vehicles, structures, and devices attention must be directed toward the assessment and management of system health. System health is the key component that links data, information, and knowledge to action. Integrated Systems Health Management (ISHM) doctrine calls for comprehensive real-time health assessment and management of systems where the distillation of raw data into information takes ...


Data Fusion Of Complementary Information From Parietal And Occipital Event Related Potentials For Early Diagnosis Of Alzheimer's Disease, Nicholas Stepenosky Dec 2006

Data Fusion Of Complementary Information From Parietal And Occipital Event Related Potentials For Early Diagnosis Of Alzheimer's Disease, Nicholas Stepenosky

Theses and Dissertations

The number of the elderly population affected by Alzheimer's disease is rapidly rising. The need to find an accurate, inexpensive, and non-intrusive procedure that can be made available to community healthcare providers for the early diagnosis of Alzheimer's disease is becoming an increasingly urgent public health concern. Several recent studies have looked at analyzing electroencephalogram signals through the use of many signal processing techniques. While their methods show great promise, the final outcome of these studies has been largely inconclusive. The inherent difficulty of the problem may be the cause of this outcome, but most likely it is ...


Random Feature Subspace Ensemble Based Approaches For The Analysis Of Data With Missing Features, Hussein Syed Mohammed Dec 2006

Random Feature Subspace Ensemble Based Approaches For The Analysis Of Data With Missing Features, Hussein Syed Mohammed

Theses and Dissertations

Missing data in real world applications is not an uncommon occurrence. It is not unusual for training, validation or field data to have missing features in some (or even all) of their instances, as bad sensors, failed pixels, malfunctioning equipment, unexpected noise causing signal saturation, data corruption, and so on, are all familiar scenarios in many practical applications.

In this thesis, the feasibility of an ensemble of classifiers trained on a feature subset space is investigated as an effective and practical solution for the missing feature problem. Two ensemble of classifiers approach motivated by the Random Subspace Method are proposed ...