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2003

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Articles 391 - 420 of 2071

Full-Text Articles in Engineering

Optimal And Intelligent Decision Making In Sustainable Development Of Electronic Products, Meimei Gao Aug 2003

Optimal And Intelligent Decision Making In Sustainable Development Of Electronic Products, Meimei Gao

Dissertations

Increasing global population and consumption are causing declining natural and social systems. Multi-lifecycle engineering and sustainable development address these issues by integrating strategies for economic successes, environmental quality, and social equity. Based on multi-lifecycle engineering and sustainable development concepts, this doctoral dissertation aims to provide decision making approaches to growing a strong industrial economy while maintaining a clean, healthy environment. The research develops a methodology to complete both the disassembly leveling and bin assignment decisions in demanufacturing through balancing the disassembly efforts, value returns, and environmental impacts. The proposed method is successfully implemented into a demanufacturing module of a Multi-LifeCycle …


Thermochemistry And Kinetic Analysis On Radicals Of Acetaldehyde + O2, Allyl Radical + O2 And Diethyl And Chlorodiethyl Sulfides, Jongwoo Lee Aug 2003

Thermochemistry And Kinetic Analysis On Radicals Of Acetaldehyde + O2, Allyl Radical + O2 And Diethyl And Chlorodiethyl Sulfides, Jongwoo Lee

Dissertations

Thermochemical properties for reactants, intermediates, products and transition states important in the radicals of acetaldehyde + O2 and allyl radical + O2 reaction systems are analyzed with density functional and ab initic calculations, to evaluate the reaction paths and kinetics in oxidation and pyrolysis. Ketene is one important product resulting from acetaldehyde oxidation; thus thermochemistry plus isomerization and conversion reactions of ketene are also analyzed. Enthalpies of formation are determined using isodesmic reaction analysis at the CBSQ composite and density functional levels. Entropies and heat capacities are determined using geometric parameters and vibration frequencies obtained at the HF/6-31G(d') …


Performance Evaluation For Communication Systems With Receive Diversity And Interference, Debang Lao Aug 2003

Performance Evaluation For Communication Systems With Receive Diversity And Interference, Debang Lao

Dissertations

Optimum combining (OC) is a well-known coherent detection technique used to combat fading and suppress cochannel interference. In this dissertation, expressions are developed to evaluate the error probability of OC for systems with multiple interferers and multiple receiving branches. Three approaches are taken to derive the expressions. The first one starts from the decision metrics of OC. It facilitates obtaining closed-form expressions for binary phase-shift keying modulation. The second approach utilizes the moment generating function of the output signal to interference plus noise ratio (SINR) and results in expressions for symbol and bit error probability for multiple phaseshift keying modulation. …


Method For Theoretically Determining The Locus And Location Of The Transmission Zeros In Microwave Filter Networks, Keehong Um Aug 2003

Method For Theoretically Determining The Locus And Location Of The Transmission Zeros In Microwave Filter Networks, Keehong Um

Dissertations

This dissertation presents a theoretical investigation of a practical method to determine quantitatively the locations and loci of complex transmission zeros (TZ's) of positively and negatively cross-coupled RF or microwave bandpass filter networks.

Bandpass filters can be effectively designed by adjusting the locations of TZ's in the complex s-domain. To locate TZ's, this practical method uses chain matrices for subsystems (discrete parts of the network) of the filter network, and can be extended to other types of filters with cross-coupled sections.

An important result is that a complex doublet, triplet and/or quadruplet, (one-, two-, or four-pairs) of TZ's are shown …


Development Of A New Apparatus To Measure Flame Spread Through A Free Stratified Fuel/Air Mixture: Numerical Modeling And Experimental Results, Fred Hovermann Aug 2003

Development Of A New Apparatus To Measure Flame Spread Through A Free Stratified Fuel/Air Mixture: Numerical Modeling And Experimental Results, Fred Hovermann

Theses and Dissertations

While flame spread through uniform fuel-air mixtures has been widely studied in combustion science, there has been relatively little attention given to the study of non-homogenous, or layered, fuel-air mixtures. However, these systems are common occurrences in such cases as terrestrial fuel spills and fuel leaks in both normal and microgravity. Conducting research on layered fuel-air mixtures and understanding the properties of flame propagation has potential implications for fire safety (both on earth and in space), as well as being of fundamental interest. The main objective behind this study is to determine flame speed, flammability regions, stability limits, and the …


Finite Element Modeling Of A Commuter Category Aircraft Seat Under Crash Loading, David William Bowen Aug 2003

Finite Element Modeling Of A Commuter Category Aircraft Seat Under Crash Loading, David William Bowen

Theses and Dissertations

This thesis describes the development and validation of a finite element model of a commuter aircraft seat under crash loading. In particular, this effort has developed an LS-DYNA model of a Beechcraft 1900C low back passenger seat.

Although air travel is one of the safest forms of transportation, crash-related fatalities do occur even in relatively low severity crashes. Many of these fatalities can be traced to the inability of production seats to absorb crash energy. The goal of this research effort is to develop a computational model of a production aircraft seat as a first step towards the development of …


Transport Properties Of Nc-Si / A-Sio2 Superlattices And Their Applications In Non-Volatile Memory, Lakshmi Susmitha Koneru Aug 2003

Transport Properties Of Nc-Si / A-Sio2 Superlattices And Their Applications In Non-Volatile Memory, Lakshmi Susmitha Koneru

Theses

The dc current-voltage characteristics, ac conductivity, equivalent capacitance, photocurrent transients of the n-Si/nanocrystalline-Si/amorphous-SiO2/Al heterostructure were measured in a wide range of illumination intensities for temperatures from 4.2 K to 300 K. Electrical transport properties of the nanocrystalline-Si/amorphous-SiO2 superlattices were discussed. The observed domination of the electron component at negative bias and of the hole component at positive bias above 0.7 V in a dc current allows to separate transport features of electrons and holes in a nc-Si/a-SiO2 superlattices. Transport of electrons is thermally activated if potential barrier at c-Si/SL interface of 70 meV is suppressed and …


Study Of Baroreceptor Sensitivity Index In Chronic Fatigue Syndrome, Diane L. Donnelly Aug 2003

Study Of Baroreceptor Sensitivity Index In Chronic Fatigue Syndrome, Diane L. Donnelly

Theses

Although numerous studies evaluate baroreflex response as part of their research protocol, only one was identified as having evaluated continuous baroreceptor response as part of a 70° head-up tilt. It was done by Youde et al. [28] and was limited in that it evaluated only sequences of three beats for lag 0. The limitations of the Youde study [28] are not present in this thesis.

The data for this thesis came from a 70° head-up tilt study performed on chronic fatigue syndrome subjects by LaManca et al. [3] at the East Orange VA Medical Center. Baroreflex was not evaluated as …


Synthesis Of Nano/Micro Particles Using Supercritical Method And Particle Characterization, Abhijit Aniruddha Gokhale Aug 2003

Synthesis Of Nano/Micro Particles Using Supercritical Method And Particle Characterization, Abhijit Aniruddha Gokhale

Theses

The thesis work consists of the two parts, jet behavior of solvents (ethanol and acetone) and the particle formation using SAS method. In the first part, the study of the effects of process parameters like temperature, pressure, injection velocity and internal diameter of nozzle on liquid jets are studied. The critical pressure for which liquid jet of solvents changes to gas - like jet, is investigated.

In the second part, the experiments are done to study the process of the particle formation using SAS method. Effects of process parameters like pressure, injection velocity of solution, the inner diameter of nozzle …


Issues Of Seismic Response And Retrofit For Critical Substation Equipment, Seyed Ali Hashemi Nezhad Ashrafi Aug 2003

Issues Of Seismic Response And Retrofit For Critical Substation Equipment, Seyed Ali Hashemi Nezhad Ashrafi

Theses

This study focuses on means to reduce the seismic hazard for transformer-bushing systems and different issues of the response and rehabilitation of transformers. The primary means of seismic mitigation investigated is the use of the Friction Pendulum System (FPS) bearings to seismically isolate transformers. This is done by developing a finite element model representing the behavior of FPS bearings and implementing this model on to ADINA finite element package for further use in analytical studies. This model is used to study the behavior of isolated primary-secondary systems and the effects of parameters like different FPS radii or vertical excitations. Also …


The Influence Of Exercise On Oxygen Uptake In Mild Hypertension, Matthew Joseph Herban Aug 2003

The Influence Of Exercise On Oxygen Uptake In Mild Hypertension, Matthew Joseph Herban

Theses

The amount of oxygen used by muscle cells increase with exercise. The two body systems that influence the amount of oxygen delivered are the cardiovascular system and the pulmonary system. Two groups of patients were studied, those that were mildly hypertensive (but are not taking prescription medication for hypertension) and the control or normal group. The two groups exercised on a bicycle ergometer. Work rate was increased in steps (multiples of thirty watts) until anaerobic threshold (as measured by an ear oximeter) was reached. Heart rate, blood pressure, oxygen uptake and carbon dioxide production were measured during exercise. Their data …


Internet Traffic Over Wide Area Network - Statistical Modeling And Analysis, Yan Yi Lee Aug 2003

Internet Traffic Over Wide Area Network - Statistical Modeling And Analysis, Yan Yi Lee

Theses

This thesis provides results on trace data collecting and modeling of the Internet traffic over a Wide Area Network. The study is based on extensive data, gathered by tracing the actual packet exchange at the interfaces of devices on the WAN of BCCLS (Bergen County Cooperative Library System). A powerful network monitoring system WhatsUp Gold was employed to monitor the WAN, and logged the byte rates and packet rates sent and received at the interfaces. Different statistical distributions were employed to model the data traces. In comparison with some other statistical models - normal, lognormal, Weibull, and Pareto, which are …


Deposition And Characterization Of Laser-Ablated Silicon, Wenwen Luo Aug 2003

Deposition And Characterization Of Laser-Ablated Silicon, Wenwen Luo

Theses

Laser ablation is a powerful thin film deposition and material processing technology. In the Nonlinear Nanostructure Lab at NJIT, silicon films deposited by laser ablation have been studied for the potential applications in nonlinear optoelectronic devices. The previous studies have suggested that the deposited silicon has a hexagonal symmetry, being a polymorph of silicon that previously has been obtained only at very high pressure. This thesis is part of the continuous study and characterization of this new structure. The objective of the research was to gain better understanding of the hexagonal silicon properties as well as the mechanism that lead …


Service Differentiation In Multihop Wireless Packet Networks, Ilker Onat Aug 2003

Service Differentiation In Multihop Wireless Packet Networks, Ilker Onat

Theses

This work explores the potential of link layer scheduling combined with MAC layer prioritization for providing service differentiation in multihop wireless packet networks. As a result of limited power, multihop characteristic and mobility, packet loss ratio in wireless ad hoc networks tends to be high compared to wireline and one-hop mobile data networks. Therefore, for wireless ad hoc networks, DiffServ-like distributed service differentiation schemes are more viable than hard QoS solutions, which are mainly designed for wireline networks. The choice and implementation of proper queuing and scheduling methods, which determine how packets will use the channel when bandwidth becomes available, …


A Biologically Inspired Joint Model Using Engineering Methods To Enhance Understanding Of Muscle Activity, Richard Paradiso Aug 2003

A Biologically Inspired Joint Model Using Engineering Methods To Enhance Understanding Of Muscle Activity, Richard Paradiso

Theses

Compliant actuators and control methods have been known to exhibit similarities in human musculoskeletal systems. In order to better understand and improve the effects of force optimization under closed- loop conditions, a physical joint model was constructed with an agonist and an antagonist muscle operating under linear control. Utilizing LabVIEW software, compliant McKibben air muscles and Merlin stretch sensors, the author was able to incorporate a Bang-Bang controller and propose the inclusion of pulse width modulation (PWM) as well as a Proportional-Integral-Derivative (PD) controller to study the reflex loops under various levels of feedback sensitivity. The feedback mechanism, similar to …


Photonic Crystals Composed Of Thick Inductive And Capacitive Meshes, Jay Shah Aug 2003

Photonic Crystals Composed Of Thick Inductive And Capacitive Meshes, Jay Shah

Theses

The transmission properties of metal meshes are studied for single meshes, photonic double layers and photonic crystals. Simulations are performed with the Flomerics Micro-Stripes program for light of infrared and millimeter wavelengths. The Micro-Stripes program solves Maxwell's equations numerically and, for simulations of the transmittance of metal meshes, has been proven as good as an experiment. Input data are the geometrical parameters, the indices of refraction and the conductivity, chosen according to the Drude model. The light is assumed to be at normal incidence and the simulation results are compared with experiments.

Single layers of inductive meshes are studied for …


Co-Operative Location Updates For Mobile Nodes For Cellular Networks, Samir Shah Aug 2003

Co-Operative Location Updates For Mobile Nodes For Cellular Networks, Samir Shah

Theses

In current pure cellular networks, each and every mobile node updates it's location to the particular base station separately following certain algorithms, say timer based, mobility based or both. For the next generation wireless networks, which we can consider as a highly dense network, such location update algorithms prove to be very costly in the terms of overall location update traffic to the base station and average battery usage by each mobile node for location updates due to large number of mobile nodes for particular base station area.

Instead of using such one-to-one link for location updates, this report describes …


Production Of Nanocrystalline Nitramine Energetic Materials By Rapid Expansion Of Supercritical Solutions, Victor Stepanov Aug 2003

Production Of Nanocrystalline Nitramine Energetic Materials By Rapid Expansion Of Supercritical Solutions, Victor Stepanov

Theses

Nanotechnology is a rapidly evolving field and has been characterized as "the next industrial revolution". Nanostructured materials are receiving increasing amount of attention in fields ranging from electronics to metallurgy due to their novel and unique properties. This work was focused on exploring the benefits of nanofabrication of high density energetic materials. The work primarily focused on the feasibility and viability of recrystallization of nitramine explosives down to the nanometer crystal size (<100 nm). It is anticipated that properties of the high density energetic materials such as sensitivity, packing density, crystal quality, energetic performance will be benefited.

Rapid Expansion of Supercritical Solutions was chosen as the process most appropriate to realize the objective. Solubility of CL-20 in supercritical solutions was studied. Nitramine crystals with …


Low Interference Routing For Wireless Ad-Hoc Networks, Mohit Gupta Aug 2003

Low Interference Routing For Wireless Ad-Hoc Networks, Mohit Gupta

Theses

In this thesis the primary focus is on the problem of interference between messages. The thesis discusses why the messages are blocked in a system? How adding a message impacts the cost of all other available links, which can be established in the system.

This thesis analyzes how the availability of channels, increase in number of nodes and increase in the transmission range help in increasing the number of messages that can be handled in the network. It is also analyzes how critical is the selection of the maximum transmission range MTR, transmission range TR and required transmission range RTR. …


Design And Evaluation Of Processes For Fuel Fabrication: Quarterly Progress Report #8, Georg F. Mauer Aug 2003

Design And Evaluation Of Processes For Fuel Fabrication: Quarterly Progress Report #8, Georg F. Mauer

Fuels Campaign (TRP)

The eighth quarter of the project covered the following:

· Mr. Richard Silva continued the development of a simulation model with a Waelischmiller hot cell robot. Rich will continue to develop detailed 3-D process simulation models as his M.Sc. thesis project.

· A paper submitted for ANS for the Winter Annual Meeting on hot cell robotics was accepted for presentation and publication.

· Further advances on Concepts and Methods for Vision-Based Hot Cell Supervision and control, focusing on rule-based object recognition (Ph.D. Student Jae-Kyu Lee)

· Undergraduate student Jamil Renno created simulations of fuel pin assembly (robotic insertion of pellets …


A Combined Channel-Modified Adaptive Array Mmse Canceller And Viterbi Equalizer, Richard M. Friedman Aug 2003

A Combined Channel-Modified Adaptive Array Mmse Canceller And Viterbi Equalizer, Richard M. Friedman

Theses

In this thesis, a very simple scheme is proposed which couples a maximum-likelihood sequence estimator (MLSE) with a X-element canceller. The method makes use of the MLSE's channel estimator to modify the locally generated training sequence used to calculate the antenna array weights. This method will increase the array's degree of freedom for interference cancellation by allowing the dispersive, desired signal to pass through the array undisturbed. Temporal equalization of the desired signal is then accomplished using maximum-likelihood sequence estimation. The T-spaced channel estimator coefficients and the array weights are obtained simultaneously using the minimum mean square error criteria. The …


Elastic Brain Image Registration Using Mutual Information, Srisheela Devabhaktuni Aug 2003

Elastic Brain Image Registration Using Mutual Information, Srisheela Devabhaktuni

Theses

Image Registration is the determination of a geometrical transformation that aligns points in one image of an object with corresponding points in another image. The source image is geometrically transformed to match the target image. The geometric transformation can be rigid or non-rigid. Rigid transformations preserve straight lines and angles between straight lines. The basic rigid transformations are rotation, scaling and translation.

In this thesis non-rigid registration using B-splines is the method being used to take into account the elastic change in the brain structure. The B-spline equation is a type of curved transformation that does not preserve the straightness …


Tree Based Reliable Topology For Distributing Link State Information, Ram Narayan Krishnan Aug 2003

Tree Based Reliable Topology For Distributing Link State Information, Ram Narayan Krishnan

Theses

Finding paths that satisfy the performance requirements of applications according to link state information in a network is known as the Quality-of- Service (QoS) routing problem and has been extensively studied. However, distributing link state information may introduce a significant protocol overhead on network resources. In this thesis, the issue on how to update link state information efficiently and effectively is investigated. A theoretical framework is presented, and a high performance link state policy that is capable of minimizing the false blocking probability of connections under a given update rate constraint is proposed. Through theoretical analysis, it is shown that …


Study Of Mosfet Degradation Under Substrate Injection And Hot Carrier Degradation, Bhawar S. Patel Aug 2003

Study Of Mosfet Degradation Under Substrate Injection And Hot Carrier Degradation, Bhawar S. Patel

Theses

With continued scaling of MOSFET's, the reliability of thin gate oxides is becoming increasingly important. Degradation issues due to fabrication technology may result in misinterpretation unless the actual physical situation arising at source, drain, gate and substrate of a transistor during processing is understood. This degradation is prominent in plasma processing due to wafer charging which occurs due to the reactive ions in the plasma. The voltages developed at source and drain junctions, depending upon polarity relative to the substrate cause the source and drain junctions to be forward biased or reverse biased. Keeping in view this type of physical …


Modeling Corrosion In Oxygen Controlled Lbe Systems With Coupling Of Chemical Kinetics And Hydrodynamics-Task V: Fourth Quarterly Report 06/01/2003-08/30/2003, Samir Moujaes, Yitung Chen Aug 2003

Modeling Corrosion In Oxygen Controlled Lbe Systems With Coupling Of Chemical Kinetics And Hydrodynamics-Task V: Fourth Quarterly Report 06/01/2003-08/30/2003, Samir Moujaes, Yitung Chen

Transmutation Sciences Materials (TRP)

The Lead-Bismuth eutectic (LBE) has been determined from previous experimental studies by the Russians and the European scientific community to be a potential material that can be used as a spallation target and coolant for the TRP proposed application. Properly controlling the oxygen content in LBE can drastically reduce the LBE corrosion to structural steels. However, existing knowledge of material corrosion performance was obtained from point-wise testing with only very sparse experimental data. Scientists have noticed that the concentration of oxygen dissolved in the liquid alloy could control the corrosion rate of steels exposed to Pb or Pb-Bi. At high …


Modeling Corrosion In Oxygen Controlled Lbe Systems With Coupling Of Chemical Kinetics And Hydrodynamics-Task V: Annual Report -Phase Ii 09/01/2002-08/30/2003, Samir Moujaes, Yitung Chen Aug 2003

Modeling Corrosion In Oxygen Controlled Lbe Systems With Coupling Of Chemical Kinetics And Hydrodynamics-Task V: Annual Report -Phase Ii 09/01/2002-08/30/2003, Samir Moujaes, Yitung Chen

Transmutation Sciences Materials (TRP)

The Lead-Bismuth eutectic (LBE) has been determined from previous experimental studies by the Russians and the European scientific community to be a potential material that can be used as a spallation target and coolant for the TRP proposed application. Properly controlling the oxygen content in LBE can drastically reduce the LBE corrosion to structural steels. However, existing knowledge of material corrosion performance was obtained from point-wise testing with only very sparse experimental data. Scientists have noticed that the concentration of oxygen dissolved in the liquid alloy could control the corrosion rate of steels exposed to Pb or Pb-Bi. At high …


Synthesis And Electrochemical Properties Of K2Feo4, Ning Zhou, Shi-Hai Ye, Yong-Long Wang, Xue-Ping Gao, Dong-Feng Lin, Zuo-Xiang Zhou, De-Ying Song Aug 2003

Synthesis And Electrochemical Properties Of K2Feo4, Ning Zhou, Shi-Hai Ye, Yong-Long Wang, Xue-Ping Gao, Dong-Feng Lin, Zuo-Xiang Zhou, De-Ying Song

Journal of Electrochemistry

The K2FeO4 used for new positive electrode materials was prepared. The primary batteries were used in different concentration of electrolyte and different currents. In 9 mol/L KOH , the capacity was the best. The higher the concentration of electrolyte, the lower the electric potential was. When the batteries discharged in 0.4 C , the capacity reached 521.3 mAh/g. By XRD, we gave the reasonable explanations for the discharge products of K2FeO4. Possible mechanism of discharge is discussed.


Corrosion Fatigue And Dynamic Strain Aging Of Duplex Stainless Steel In Aqueous Solution, Chuan-Ming Tseng, I-Hsuang Lo, Wen-Ta Tsai Aug 2003

Corrosion Fatigue And Dynamic Strain Aging Of Duplex Stainless Steel In Aqueous Solution, Chuan-Ming Tseng, I-Hsuang Lo, Wen-Ta Tsai

Journal of Electrochemistry

The corrosion fatigue and dynamic strain aging behaviors of 22%Cr duplex stainless steel (DSS) in sodium chloride solutions were investigated. Austenitic 316L SS and ferrtic 430 SS were also used in this study for a comparison. The experimental results showed that no stress corrosion cracking (SCC) occurred in all these SSs tested in 3.5wt% NaCl solution at 80 ℃. However, dynamic strain aging (DSA) occurred in 316L austenitic SS and 22%Cr DSS during slow strain rate testing (SSRT) in this solution.The occurrence of DSA was dependent on solution temperature,strain rate and the presence of austenitic phase. The corrosion rate of …


Synthesis Of Polyunit Vapor Phase Inhibitor And Its Volatile Corrosion Inhibition Performance, Da-Quan Zhang, Li-Xin Gao, Guo-Ding Zhou Aug 2003

Synthesis Of Polyunit Vapor Phase Inhibitor And Its Volatile Corrosion Inhibition Performance, Da-Quan Zhang, Li-Xin Gao, Guo-Ding Zhou

Journal of Electrochemistry

A Mannich Base derivative (BMMCH), containing two morpholinum moieties and one cyclohexylamnonium moiety, was synthesized through aminomethy1 reaction. Its configuration was verified by IR and 1H-NMR. Its volatile rustproofing effect was appraised by volatile rustproofing sieve test and vapor inhabitability test. The result shows that BMMCH has good protection effect for carbon steel. BMMCH has lower volatility compared with dicyclohexylamnonium nitrite (DICHAN) via closed space volatile weight-loss test. The inhibition mechanism was studied by potentiodynamic polarization electrochemistry technique in ASTM simulated atmospheric water. The corrosion potential of carbon steel electrode shifted to a negative direction when BMMCH was joined …


Effect Of Heat Laminating Aggregation Status Of Polymer Lithium-Ion Battery Cathode On Battery Performance, Ming-Gang Jin, Quan-Feng Dong, Ming-Sen Zheng, Li Huang, Hui-Qun Cai, Jin-Qua You, Zu-Geng Lin Aug 2003

Effect Of Heat Laminating Aggregation Status Of Polymer Lithium-Ion Battery Cathode On Battery Performance, Ming-Gang Jin, Quan-Feng Dong, Ming-Sen Zheng, Li Huang, Hui-Qun Cai, Jin-Qua You, Zu-Geng Lin

Journal of Electrochemistry

Multi-layer heat laminated polymer lithium ion battery was made, the effect of temperature of cathode laminating on battry performance was also investigated. It was discovered that suitable temperature of cathode laminating is critical to battery performance and is a key parameter to manufacture process control of polymer lithium ion battery.