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Articles 1 - 15 of 15
Full-Text Articles in Engineering
A Synchronous Primary-Side Dimming Controller For Cold-Cathode Fluorescent Lamp Ballast, Jenn-Jong Shieh
A Synchronous Primary-Side Dimming Controller For Cold-Cathode Fluorescent Lamp Ballast, Jenn-Jong Shieh
Journal of Marine Science and Technology
In this paper, a rectified quasi-sinusoidal pulse width modulation (RQSPWM) controller is first proposed for the cold-cathode fluorescent lamp (CCFL) ballast to achieve a synchronous primary-side dimming control. It is seen that, with the novel controller, not only the lamp flickering problem and the thermometer effect can be eliminated but also the useful photo-coupler in secondary side can be avoided to reduce cost. Then, small signal models of the CCFL ballast and the proposed RQSPWM dimming controller are derived to analyze the performance of the ballast system and help corroborate hardware loop measurements. Finally, a prototype is constructed for verifying …
Developing A Gis And Hydrological Modeling Approach For Sustainable Water Resources Management In The West Bank -- Palestine, Walid Wajeeh Sabbah
Developing A Gis And Hydrological Modeling Approach For Sustainable Water Resources Management In The West Bank -- Palestine, Walid Wajeeh Sabbah
Theses and Dissertations
This research deals with setting up a GIS and hydrological modeling based approach for sustainable water resources management in the West Bank of Palestine. This water sustainability approach took into consideration the water balance, the social, the economic, the demographic, the environmental, and the institutional components in order to enhance and promote the sustainable development in Palestine, both on the short and long runs. To evaluate the water balance component, a methodology was introduced to create the Water Sustainability Map (WSM). Since the groundwater is currently the only accessible water source by the Palestinians, the WSM is represented by the …
Electrothermomechanical Modeling Of A Surface-Micromachined Linear Displacement Microactuator, Christian D. Lott
Electrothermomechanical Modeling Of A Surface-Micromachined Linear Displacement Microactuator, Christian D. Lott
Theses and Dissertations
The electrothermomechanical characteristics of an electrically-heated polycrystallinesilicon microactuator are explored. Using finite-difference techniques, an electrothermal model based on the balance of heat dissipation and heat losses is developed. For accurate simulation, the relevant temperature dependent properties from the microactuator material are included in the model. The electrothermal model accurately predicts the steady-state power required to hold position, and the energy consumed during the thermal transient. Thermomechanical models use the predictions of temperature from the electrothermal solution to calculate displacement and force from pseudo-rigid-body approximations and commercial finite-element code. The models are verified by comparing experimental data to simulation results of …
Modeling The Effect Of P53 On Tumor Heterogeneity And The Mutator Phenotype, Melissa Ryan, Matthew J. Berryman, Derek Abbott
Modeling The Effect Of P53 On Tumor Heterogeneity And The Mutator Phenotype, Melissa Ryan, Matthew J. Berryman, Derek Abbott
Faculty of Engineering - Papers (Archive)
p53 is an important gene, involved in apoptosis (programmed cell death), DNA repair, and cell cycle progression. We explore the selective advantages and disadvantages of mutations in the p53 gene on tumor cells, and the heterogeneity of tumor cell populations. Based on an evolutionary computational approach, our model considers changes in mutation rate caused by lack of DNA repair processes, and the lack of apoptosis caused by mutations in p53. We find that the degree of robustness of p53 to mutations has a significant effect on the tumor heterogeneity and “fitness”, with clinical consequences for people who inherit p53 mutations.
Hierarchical Bayesian Modeling Of The Movement Of Ice Streams, L M. Berliner, Noel A. Cressie, Kenneth Jezek, Yongku Kim, Calvin Lam
Hierarchical Bayesian Modeling Of The Movement Of Ice Streams, L M. Berliner, Noel A. Cressie, Kenneth Jezek, Yongku Kim, Calvin Lam
Faculty of Engineering and Information Sciences - Papers: Part A
Modern studies of the behaviors of glaciers, ice-sheets, and ice-streams rely heavily on both observations and physically based models. Data acquired via remote-sensing provide critical information on geometry and movement of ice over large sections of the Antarctic and Greenland. Though these datasets represent significant advances in terms of spatial coverage and the range of processes we can observe, the physical systems to be modeled are nevertheless incompletely observed. Uncertainties associated with measurement errors are also present. In addition, physical models are also subject to uncertainties. Hence, there is a need for combining observations and models in a fashion that …
Dynamic Modeling And Simulation Of A Multi Effect Humidification-Dehumidification Desalination Unit, Mohammed I. Sohel, B Dawoud
Dynamic Modeling And Simulation Of A Multi Effect Humidification-Dehumidification Desalination Unit, Mohammed I. Sohel, B Dawoud
Faculty of Engineering and Information Sciences - Papers: Part A
Recently solar distillation using Multi Effect Humidification-dehumidification (MEH) cycle is receiving special attention. In this communication detailed models of MEH are presented that take into account most of the dynamic behavior with reasonable accuracy. Using these models simulation was carried out and the results of simulation were discussed in this paper. To find out the competence of the newly developed models, some of the simulation results were compared with the available experimental data in the literature. It turned out that the result of simulation give a very good agreement with the experimental data. The maximum deviation between simulation and experimental …
A New Paradigm Of Modeling Watershed Water Quality, Fan Zhang
A New Paradigm Of Modeling Watershed Water Quality, Fan Zhang
Electronic Theses and Dissertations
Accurate models to reliably predict sediment and chemical transport in watershed water systems enhance the ability of environmental scientists, engineers and decision makers to analyze the impact of contamination problems and to evaluate the efficacy of alternative remediation techniques and management strategies prior to incurring expense in the field. This dissertation presents the conceptual and mathematical development of a general numerical model simulating (1) sediment and reactive chemical transport in river/stream networks of watershed systems; (2) sediment and reactive chemical transport in overland shallow water of watershed systems; and (3) reactive chemical transport in three-dimensional subsurface systems. Through the decomposition …
Numerical Modeling Of Synthetic Jets In Quiescent Air With Moving Boundary Conditions, Nicholas D. Castro
Numerical Modeling Of Synthetic Jets In Quiescent Air With Moving Boundary Conditions, Nicholas D. Castro
Theses and Dissertations
Flow control is a key factor in optimizing the performance of any vehicle moving through fluids. Particularly, in aerodynamics there are many potential benefits for implementing synthetic jets to achieve aircraft designs with less moving parts, uper- maneuverability, and separation control for fuel economy. Piezoelectric synthetic jets are of special interest because of their lightweight and low power consumption. Numerous publications on such jets are available. Actuator properties and boundary conditions relevant to this particular application however are often overlooked. The focus of this project is to numerically model synthetic jets in quiescent air to study the influence of cavity …
Modeling And Simulation Of Long Term Degradation And Lifetime Of Deep-Submicron Mos Device And Circuit, Zhi Cui
Electronic Theses and Dissertations
Long-term hot-carrier induced degradation of MOS devices has become more severe as the device size continues to scale down to submicron range. In our work, a simple yet effective method has been developed to provide the degradation laws with a better predictability. The method can be easily augmented into any of the existing degradation laws without requiring additional algorithm. With more accurate extrapolation method, we present a direct and accurate approach to modeling empirically the 0.18-ìm MOS reliability, which can predict the MOS lifetime as a function of drain voltage and channel length. With the further study on physical mechanism …
An Automated Methodology For A Comprehensive Definition Of The Supply Chain Using Generic Ontological Components, Mohamed Fayez
An Automated Methodology For A Comprehensive Definition Of The Supply Chain Using Generic Ontological Components, Mohamed Fayez
Electronic Theses and Dissertations
Today, worldwide business communities are in the era of the Supply Chains. A Supply Chain is a collection of several independent enterprises that partner together to achieve specific goals. These enterprises may plan, source, produce, deliver, or transport materials to satisfy an immediate or projected market demand, and may provide the after sales support, warranty services, and returns. Each enterprise in the Supply Chain has roles and elements. The roles include supplier, customer, or carrier and the elements include functional units, processes, information, information resources, materials, objects, decisions, practices, and performance measures. Each enterprise, individually, manages these elements in addition …
The Development Of A Fuzzy Model To Quantify Training Andeducational Factors And The Resulting Impact On Student Successand Lear, Chandre Butler
The Development Of A Fuzzy Model To Quantify Training Andeducational Factors And The Resulting Impact On Student Successand Lear, Chandre Butler
Electronic Theses and Dissertations
The utilization of fuzzy mathematical modeling for quantification of the quality of training and educational delivery is an innovative application that can result in measurable and repeatable results. This research was designed to apply proven quantification techniques and Industrial Engineering methodologies to a nontraditional environment. The outcomes of this research provide the foundation, initial steps and preliminary validation for the development of a systematic fuzzy theoretical model to be applied for the quantification of various areas within training and education delivery. The test bed for this methodology is Orange County Public School system, the twelfth largest school district in the …
Modeling The Fate And Transport Of Chlorinated Benzenes In Baton Rouge Bayou, Sudheer Nimmagadda
Modeling The Fate And Transport Of Chlorinated Benzenes In Baton Rouge Bayou, Sudheer Nimmagadda
LSU Master's Theses
Knowledge of the fate and transport of chlorinated benzenes is necessary at certain sites for effective remediation of contaminated soils using plants. Current research is examining the capability of wetland plants to catalyze degradation or attenuate migration, but again requires knowledge of the uptake of contaminants from an aqueous environment. A two stage model was used to estimate the rate of uptake of contaminants from sediments. The first stage of the model predicts pollutant leaching rates from sediments to the overlying water, which would then be fed into the plant or bioreactor model systems. In this study the flux from …
Analysis And Shape Modeling Of Thin Piezoelectric Actuators, Makram Mouhli
Analysis And Shape Modeling Of Thin Piezoelectric Actuators, Makram Mouhli
Theses and Dissertations
The field of smart materials is an increasingly growing area of research. In aerodynamics applications especially, transducers have to fulfill a series of requirements such as light weight, size, energy consumption, robustness and durability. Piezoelectric transducers, devices which transform an electrical signal into motion, fulfill many of these requirements. Specifically, piezoelectric composites are of interest due to their added toughness and ease of integration into a structure. Resulting composites have a characteristic initial curvature with accompanying residual stresses that are responsible for enhanced performance, relative to flat actuators, when the active material is energized. A number of transducer designs based …
A Microphone Array System For Multimedia Applications With Near-Field Signal Targets, Y. Rosa Zheng, M. El-Tanany, R. A. Goubran, Hongchi Shi
A Microphone Array System For Multimedia Applications With Near-Field Signal Targets, Y. Rosa Zheng, M. El-Tanany, R. A. Goubran, Hongchi Shi
Electrical and Computer Engineering Faculty Research & Creative Works
A microphone array beamforming system is proposed for multimedia communication applications using four sets of small planar arrays mounted on a computer monitor. A new virtual array approach is employed such that the original signals received by the array elements are weighted and delayed to synthesize a large, nonuniformly spaced, harmonically nested virtual array covering the frequency band [50, 7000] Hz of the wideband telephony. Subband multirate processing and near-field beamforming techniques are then used jointly by the nested virtual array to improve the performances in reverberant environments. A new beamforming algorithm is also proposed using a broadband near-field spherically …
Runoff Production In The Upper Rio Chagres Watershed, Panama, Fred Ogden
Runoff Production In The Upper Rio Chagres Watershed, Panama, Fred Ogden
Fred L. Ogden
Runoff production in tropical watersheds is governed by a wide variety of potential sources and there have been few rigorous studies to date. The 414 km2 upper Río Chagres basin offers a unique opportunity to better understand the runoff production mechanisms in tropical watersheds through data analysis and modeling with rainfall and runoff data. Flow data and tipping bucket rain gage data are available at both the basin outlet (Chico gage) and for an 80.6 km2 internal basin location (Piedras gage). Modeling is performed using the Sacramento Soil Moisture Accounting Model (SAC-SMA), calibrated using data from 2000 and verified using …