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Title: REGIONAL POLITICAL POWER IN FLORIDA.
Creator: Caouette, Bradley J., Jewett, Aubrey, University of Central Florida
Abstract / Description: According to well-known political science professors in Florida universities, the only constitutional mandate to which the Florida Legislature must adhere is to pass a balanced budget (MacManus, Jewett, Bonanza, & Dye, 2015, p. 184). The process begins with each of Florida's state agencies crafting their individual budgets almost as soon as the new budget year takes effect (July 1). These budgets are submitted to the Governor's office where they are reviewed by staff and then ultimately...
Show moreAccording to well-known political science professors in Florida universities, the only constitutional mandate to which the Florida Legislature must adhere is to pass a balanced budget (MacManus, Jewett, Bonanza, & Dye, 2015, p. 184). The process begins with each of Florida's state agencies crafting their individual budgets almost as soon as the new budget year takes effect (July 1). These budgets are submitted to the Governor's office where they are reviewed by staff and then ultimately submitted to the legislature (p. 243). During the budget process, legislators are careful to ensure that they procure state dollars, oftentimes referred to as "pork," for the constituents who elected them (p. 209). The premise of this paper is to explore the possibility that political influence or power has a direct effect on the amount of tax dollars appropriated to Florida's 67 counties, 10 media markets, and in turn to Florida's three geographic regions. First, a legislative power index is developed. We then analyze county by county allocations of budget year 2016/2017 and the legislative power index to determine if there is a relationship between the amount of money distributed by county and the legislative influence that exists in that county. The research finds that the legislative power of a county as measured by the legislative power index had no statistically significant effect on per capita allocation. The presence of a state university and miles of roadway in a county did have an influence.
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Date Issued: 2016
Identifier: CFH2000144, ucf:45944
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFH2000144

Title: STUDY OF ESD EFFECTS ON RF POWER AMPLIFIERS.
Creator: Narasimha Raju, Divya, Yuan, Jiann, University of Central Florida
Abstract / Description: Today, ESD is a major consideration in the design and manufacture of ICs. ESD problems are increasing in the electronics industry because of the increasing trend toward higher speed and smaller device sizes. There is growing interest in knowing the effects of ESD protection circuit on the performance of semiconductor integrated circuits (ICs) because of the impact it has on core RF circuit performance. This study investigated the impact of ESD protection circuit on RF Power amplifiers. Even...
Show moreToday, ESD is a major consideration in the design and manufacture of ICs. ESD problems are increasing in the electronics industry because of the increasing trend toward higher speed and smaller device sizes. There is growing interest in knowing the effects of ESD protection circuit on the performance of semiconductor integrated circuits (ICs) because of the impact it has on core RF circuit performance. This study investigated the impact of ESD protection circuit on RF Power amplifiers. Even though ESD protection for digital circuits has been known for a while, RF-ESD is a challenge. From a thorough literature search on prior art ESD protection circuits, Silicon controlled rectifier was found to be most effective and reliable ESD protection for power amplifier circuit. A SCR based ESD protection was used to protect the power amplifier and a model was developed to gain better understanding of ESD protected power amplifiers. Simulated results were compared and contrasted against theoretically derived equations. A 5.2GHz fully ESD protected Class AB power amplifier was designed and simulated using TSMC 0.18 um technology. Further, the ESD protection circuit was added to a cascoded Class-E power amplifier operating at 5.2 GHz. ADS simulation results were used to analyze the PA's RF performance degradation. Various optimization techniques were used to improve the RF circuit performance.
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Date Issued: 2011
Identifier: CFE0003630, ucf:48881
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0003630

Title: Three-Dimensional Simulation Study of Low Voltage ((<)100V) Superjunction Lateral DMOS power transistors.
Creator: Garcia, Jhonatan, Yuan, Jiann-Shiun, Sundaram, Kalpathy, Fan, Deliang, University of Central Florida
Abstract / Description: A new revolutionary concept was presented two decades ago, known as (")semiconductor Superjunction (SJ) theory(") to enhance the trade-off relationship between speci?c on resistance, Rsp, and off-state breakdown voltage, BV, in medium to high voltages (more than 100 V) power MOSFETs. The SJ concept was ?rst applied and commercialized to vertical structures, but it hasn't been used yet in low voltage MOSFETs with lateral structures. This thesis provides a review of the most common structures,...
Show moreA new revolutionary concept was presented two decades ago, known as (")semiconductor Superjunction (SJ) theory(") to enhance the trade-off relationship between speci?c on resistance, Rsp, and off-state breakdown voltage, BV, in medium to high voltages (more than 100 V) power MOSFETs. The SJ concept was ?rst applied and commercialized to vertical structures, but it hasn't been used yet in low voltage MOSFETs with lateral structures. This thesis provides a review of the most common structures, principles and design techniques for discrete power MOSFETs. It also presents a simulation study of the application of these SJ concepts in the design of a Low Voltage SJ LDMOS transistor, using TCAD software. To make the device commercially feasible, this device design targets aggressive goals such as an off-state Breakdown Voltage of 60V with Rspof 20 miliohms per milimiter square. This study includes the analysis of the ?ow process for the fabrication of this transistor, using semiconductor technologies, and the simulation results, including Breakdown Voltage, on-state resistance, electric ?eld distribution among others simulation analysis.
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Date Issued: 2016
Identifier: CFE0006306, ucf:51600
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006306

Title: ANALYSIS AND SIMULATION TOOLS FOR SOLAR ARRAY POWER SYSTEMS.
Creator: Pongratananukul, Nattorn, Kasparis, Takis, University of Central Florida
Abstract / Description: This dissertation presents simulation tools developed specifically for the design of solar array power systems. Contributions are made in several aspects of the system design phases, including solar source modeling, system simulation, and controller verification. A tool to automate the study of solar array configurations using general purpose circuit simulators has been developed based on the modeling of individual solar cells. Hierarchical structure of solar cell elements, including...
Show moreThis dissertation presents simulation tools developed specifically for the design of solar array power systems. Contributions are made in several aspects of the system design phases, including solar source modeling, system simulation, and controller verification. A tool to automate the study of solar array configurations using general purpose circuit simulators has been developed based on the modeling of individual solar cells. Hierarchical structure of solar cell elements, including semiconductor properties, allows simulation of electrical properties as well as the evaluation of the impact of environmental conditions. A second developed tool provides a co-simulation platform with the capability to verify the performance of an actual digital controller implemented in programmable hardware such as a DSP processor, while the entire solar array including the DC-DC power converter is modeled in software algorithms running on a computer. This "virtual plant" allows developing and debugging code for the digital controller, and also to improve the control algorithm. One important task in solar arrays is to track the maximum power point on the array in order to maximize the power that can be delivered. Digital controllers implemented with programmable processors are particularly attractive for this task because sophisticated tracking algorithms can be implemented and revised when needed to optimize their performance. The proposed co-simulation tools are thus very valuable in developing and optimizing the control algorithm, before the system is built. Examples that demonstrate the effectiveness of the proposed methodologies are presented. The proposed simulation tools are also valuable in the design of multi-channel arrays. In the specific system that we have designed and tested, the control algorithm is implemented on a single digital signal processor. In each of the channels the maximum power point is tracked individually. In the prototype we built, off-the-shelf commercial DC-DC converters were utilized. At the end, the overall performance of the entire system was evaluated using solar array simulators capable of simulating various I-V characteristics, and also by using an electronic load. Experimental results are presented.
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Date Issued: 2005
Identifier: CFE0000331, ucf:46290
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0000331

Title: MODELING AND DIGITAL CONTROL OF HIGH FREQUENCY DC-DC POWER CONVERTERS.
Creator: Wen, Yangyang, Batarseh, Issa, University of Central Florida
Abstract / Description: The power requirements for leading edge digital integrated circuits have become increasingly demanding. Power converter systems must be faster, more flexible, more precisely controllable and easily monitored. Meanwhile, in addition to control process, the new functions such as power sequencing, communication with other systems, voltage dynamic programming,load line specifications, phase current balance, protection, power status monitoring and system diagnosis are going into today's power...
Show moreThe power requirements for leading edge digital integrated circuits have become increasingly demanding. Power converter systems must be faster, more flexible, more precisely controllable and easily monitored. Meanwhile, in addition to control process, the new functions such as power sequencing, communication with other systems, voltage dynamic programming,load line specifications, phase current balance, protection, power status monitoring and system diagnosis are going into today's power supply systems. Digital controllers, compared withanalog controllers, are in a favorable position to provide basic feedback control as well as those power management functions with lower cost and great flexibility. The dissertation gives an overview of digital controlled power supply systems bycomparing with conventional analog controlled power systems in term of system architecture,modeling methods, and design approaches. In addition, digital power management, as one of the most valuable and "cheap" function, is introduced in Chapter 2. Based on a leading-edge digital controller product, Chapter 3 focuses on digital PID compensator design methodologies, design issues, and optimization and development of digital controlled single-phase point-of-load (POL)dc-dc converter. Nonlinear control is another valuable advantage of digital controllers over analogcontrollers. Based on the modeling of an isolated half-bridge dc-dc converter, a nonlinear control method is proposed in Chapter 4. Nonlinear adaptive PID compensation scheme is implemented based on digital controller Si8250. The variable PID coefficient during transients improves power system's transient response and thus output capacitance can be reduced to save cost. In Chapter 5, another nonlinear compensation algorithm is proposed for asymmetric flybackforward half bridge dc-dc converter to reduce the system loop gain's dependence on the input voltage, and improve the system's dynamic response at high input line. In Chapter 6, a unified pulse width modulation (PWM) scheme is proposed to extend the duty-cycle-shift (DCS) control, where PWM pattern is adaptively generated according to the input voltage level, such that the power converter's voltage stress are reduced and efficiency is improved. With the great flexibility of digital PWM modulation offered by the digital controller Si8250, the proposed control scheme is implemented and verified. Conclusion of the dissertation work and suggestions for future work in related directions are given in final Chapter.
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Date Issued: 2007
Identifier: CFE0001612, ucf:47172
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001612

Title: The new nationalism and the Negro struggle.
Creator: Wohlforth, Tim
Date Issued: c1968
Identifier: 2667392, CFDT2667392, ucf:4994
Format: Document (PDF)
PURL: http://purl.flvc.org/FCLA/DT/2667392

Title: COMPARISON OF THEORETICAL MODELS OF POWER SPECTRAL DENSITY TO THE EXPERIMENTAL VALUE FOR SPECTRUM OF IRRADIANCE FLUCTUATIONS.
Creator: Hershberger, Craig, Phillips, Ronald, University of Central Florida
Abstract / Description: A propagation experiment was designed, assembled, and conducted on an extended range to verify theoretical temporal models for weak to strong fluctuation theory. Laser light intensity was propagated over terrain at the Kennedy Space Center (Florida), and detected using optical receivers at a distance of 13.3 Km from the optical source. The intensity data from the experiment was used to generate an experimental Power Spectral Density (PSD) function. The theoretical Mutual Coherence Function ...
Show moreA propagation experiment was designed, assembled, and conducted on an extended range to verify theoretical temporal models for weak to strong fluctuation theory. Laser light intensity was propagated over terrain at the Kennedy Space Center (Florida), and detected using optical receivers at a distance of 13.3 Km from the optical source. The intensity data from the experiment was used to generate an experimental Power Spectral Density (PSD) function. The theoretical Mutual Coherence Function (MCF) and Wave Structure Function (WSF) as set forth by Andrews/Phillips , were evaluated to determine the effective relationship between the statistical moments of the random optical field and the laser light intensity. Two scales of interest were identified (refractive large-scale and diffractive small-scale) and plotted revealing the characteristic shape of each component. In addition, statistical principles applied to the correlation/covariance function relationship and a graphical convolution process were used to generate a theoretical PSD function. Further, utilizing Taylor's "frozen turbulence" hypothesis an analysis of the theoretical temporal covariance function was performed. Functional forms for refractive and diffractive log-irradiance components were developed and used to generate a second theoretical PSD function. Finally, the experimental and theoretical Power Spectral Density functions are plotted on the same graph and a comparison is performed.
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Date Issued: 2008
Identifier: CFE0002403, ucf:47734
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0002403

Title: HIGH LINEARITY 5.8 GHZ POWER AMPLIFIER WITH AN INTERNAL LINEARIZER.
Creator: Wang, Yiheng, Yuan, Jiann S., University of Central Florida
Abstract / Description: A 5.8 GHz RF Power Amplifier (PA) is designed and fabricated in this work, which has very high linearity through a built-in linearizer. The PA is designed, post-layout simulated by Agilent Advanced Design System (ADS) software and fabricated by Win-Semiconductors 0.15µm pHEMT process technology. The post-layout simulation results illustrate the power amplifier can obtained an output power of 23.98 dBm, a power gain of 32.28 dB and a power added efficiency (PAE) of 29% at saturation region,...
Show moreA 5.8 GHz RF Power Amplifier (PA) is designed and fabricated in this work, which has very high linearity through a built-in linearizer. The PA is designed, post-layout simulated by Agilent Advanced Design System (ADS) software and fabricated by Win-Semiconductors 0.15µm pHEMT process technology. The post-layout simulation results illustrate the power amplifier can obtained an output power of 23.98 dBm, a power gain of 32.28 dB and a power added efficiency (PAE) of 29% at saturation region, the 3rd intermodulation distortion (IMD3) of -37.7 dBc at 0 dBm input power is attained when operation frequency is 5.8 GHz. We finally obtain that the output power of 17.97 dBm and power gain of 27.97 dB at input power of -10 dBm, PAE of 11.65% at input power of 0 dBm and the IMD3 of -25.66 dBc at -20 dBm input power by measurement, when operation frequency is 5.2 GHz. So the overall RF performance of the PA demonstrates high power, high efficiency and high linearity.
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Date Issued: 2011
Identifier: CFE0003615, ucf:48857
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0003615

Title: STEADY STATE AND DYNAMIC ANALYSIS AND OPTIMIZATION OF SINGLE-STAGE POWER FACTOR CORRECTION CONVERTERS.
Creator: Rustom, Khalid, Batarseh, Issa, University of Central Florida
Abstract / Description: With the increased interest in applying Power Factor Correction (PFC) to off-line AC-DC converters, the field of integrated, single-stage PFC converter development has attracted wide attention. Considering the tens of millions of low-to-medium power supplies manufactured each year for today's rechargeable equipment, the expected reduction in cost by utilizing advanced technologies is significant. To date, only a few single-stage topologies have made it to the market due to the inherit...
Show moreWith the increased interest in applying Power Factor Correction (PFC) to off-line AC-DC converters, the field of integrated, single-stage PFC converter development has attracted wide attention. Considering the tens of millions of low-to-medium power supplies manufactured each year for today's rechargeable equipment, the expected reduction in cost by utilizing advanced technologies is significant. To date, only a few single-stage topologies have made it to the market due to the inherit limitations in this structure. The high voltage and current stresses on the components led to reduced efficiency and an increased failure rate. In addition, the component prices tend to increase with increased electrical and thermal requirements, jeopardizing the overarching goal of price reduction. The absence of dedicated control circuitry for each stage complicates the power balance in these converters, often resulting in an oversized bus capacitance. These factors have impeded widespread acceptance of these new techniques by manufacturers, and as such single stage PFC has remained largely a drawing board concept. This dissertation will present an in-depth study of innovative solutions that address these problems directly, rather than proposing more topologies with the same type of issues. The direct energy transfer concept is analyzed and presented as a promising solution for the majority of the single-stage PFC converter limitations. Three topologies are presented and analyzed based on this innovative structure. To complete the picture, the dynamics of a variety of single-stage converters can be analyzed using a proposed switched transformer model.
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Date Issued: 2007
Identifier: CFE0001940, ucf:47449
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001940

Title: High Performance Low Voltage Power MOSFET for High-Frequency Synchronous Buck Converters.
Creator: Yang, Boyi, Shen, Zheng, Yuan, Jiann-Shiun, Sundaram, Kalpathy, Wu, Xinzhang, Xu, Shuming, University of Central Florida
Abstract / Description: Power management solutions such as voltage regulator (VR) mandate DC-DC converters with high power density, high switching frequency and high efficiency to meet the needs of future computers and telecom equipment. The trend towards DC-DC converters with higher switching frequency presents significant challenges to power MOSFET technology. Optimization of the MOSFETs plays an important role in improving low-voltage DC-DC converter performance. This dissertation focuses on developing and...
Show morePower management solutions such as voltage regulator (VR) mandate DC-DC converters with high power density, high switching frequency and high efficiency to meet the needs of future computers and telecom equipment. The trend towards DC-DC converters with higher switching frequency presents significant challenges to power MOSFET technology. Optimization of the MOSFETs plays an important role in improving low-voltage DC-DC converter performance. This dissertation focuses on developing and optimizing high performance low voltage power MOSFETs for high frequency applications.With an inherently large gate charge, the trench MOSFET suffers significant switching power losses and cannot continue to provide sufficient performance in high frequency applications. Moreover, the influence of parasitic impedance introduced by device packaging and PCB assembly in board level power supply designs becomes more pronounced as the output voltage continues to decrease and the nominal current continues to increase. This eventually raises the need for highly integrated solutions such as power supply in package (PSiP) or on chip (PSoC). However, it is often more desirable in some PSiP architectures to reverse the source/drain electrodes from electrical and/or thermal point of view. In this dissertation, a stacked-die Power Block PSiP architecture is first introduced to enable DC-DC buck converters with a current rating up to 40 A and a switching frequency in the MHz range. New high- and low-side NexFETs are specially designed and optimized for the new PSiP architecture to maximize its efficiency and power density. In particular, a new NexFET structure with its source electrode on the bottom side of the die (source-down) is designed to enable the innovative stacked-die PSiP technology with significantly reduced parasitic inductance and package footprint.It is also observed that in synchronous buck converter very fast switching of power MOSFETs sometimes leads to high voltage oscillations at the phase node of the buck converter, which may introduce additional power loss and cause EMI related problems and undesirable electrical stress to the power MOSFET. At the same time, the synchronous MOSFET plays an important role in determining the performance of the synchronous buck converter. The reverse recovery of its body diode and the Cdv/dt induced false trigger-on are two major mechanisms that impact the performance of the SyncFET. This dissertation introduces a new approach to effectively overcome the aforementioned challenges associated with the state-of-art technology. The threshold voltage of the low-side NexFET is intentionally reduced to minimize the conduction and body diode related power losses. Meanwhile, a monolithically integrated gate voltage pull-down circuitry is proposed to overcome the possible Cdv/dt induced turn-on issue inadvertently induced by the low VTH SynFET.Through extensive modeling and simulation, all these innovative concepts are integrated together in a power module and fabricated with a 0.35(&)#181;m process. With all these novel device technology improvements, the new power module delivers a significant improvement in efficiency and offers an excellent solution for future high frequency, high current density DC-DC converters. Megahertz operation of a Power Block incorporating these new device techniques is demonstrated with an excellent efficiency observed.
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Date Issued: 2012
Identifier: CFE0004642, ucf:49885
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004642

Title: SOFT POWER AND HARD POWER APPROACHES IN U.S. FOREIGN POLICY: A CASE STUDY COMPARISON IN LATIN AMERICA.
Creator: Weinbrenner, John, Dolan, Chris, University of Central Florida
Abstract / Description: The purpose of this study was to examine the effects of soft power versus hard power in U.S. policy towards Latin America. In recent years America's unipolar moment has been challenged from populist leaders in the region to its inability to get a handle on the flow of illegal immigrants and illicit drugs that reach its shores. This thesis is a step to understanding the difference between power and influence as well as the effects of hard power and soft power in U.S. foreign policy. A...
Show moreThe purpose of this study was to examine the effects of soft power versus hard power in U.S. policy towards Latin America. In recent years America's unipolar moment has been challenged from populist leaders in the region to its inability to get a handle on the flow of illegal immigrants and illicit drugs that reach its shores. This thesis is a step to understanding the difference between power and influence as well as the effects of hard power and soft power in U.S. foreign policy. A historical comparative case study analysis has been conducted utilizing the cases of FDR's Good Neighbor policy and Reagan's contra war policies. This qualitative approach examined specific short-term and long-term goals of each policy and analyzed each strategy's ability to achieve those stated goals. The results of the study reveal that both soft and hard power approaches can have positive as well as negative effects on American influence in Latin America.
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Date Issued: 2007
Identifier: CFE0001600, ucf:47175
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001600

Title: REALIZATION OF POWER FACTOR CORRECTION AND MAXIMUM POWER POINT TRACKING FOR LOW POWER WIND TURBINES.
Creator: Gamboa, Gustavo, Batarseh, Issa, University of Central Florida
Abstract / Description: In recent years, wind energy technology has become one of the top areas of interest for energy harvesting in the power electronics world. This interest has especially peaked recently due to the increasing demand for a reliable source of renewable energy. In a recent study, the American Wind Energy Association (AWEA) ranked the U.S as the leading competitor in wind energy harvesting followed by Germany and Spain. Although the United States is the leading competitor in this area, no one has...
Show moreIn recent years, wind energy technology has become one of the top areas of interest for energy harvesting in the power electronics world. This interest has especially peaked recently due to the increasing demand for a reliable source of renewable energy. In a recent study, the American Wind Energy Association (AWEA) ranked the U.S as the leading competitor in wind energy harvesting followed by Germany and Spain. Although the United States is the leading competitor in this area, no one has been able successfully develop an efficient, low-cost AC/DC convertor for low power turbines to be used by the average American consumer. There has been very little research in low power AC/DC converters for low to medium power wind energy turbines for battery charging applications. Due to the low power coefficient of wind turbines, power converters are required to transfer the maximum available power at the highest efficiency. Power factor correction (PFC) and maximum power point tracking (MPPT) algorithms have been proposed for high power wind turbines. These turbines are out of the price range of what a common household can afford. They also occupy a large amount of space, which is not practical for use in one's home. A low cost AC/DC converter with efficient power transfer is needed in order to promote the use of cheaper low power wind turbines. Only MPPT is implemented in most of these low power wind turbine power converters. The concept of power factor correction with MPPT has not been completely adapted just yet. The research conducted involved analyzing the effect of power factor correction and maximum power point tracking algorithm in AC/DC converters for wind turbine applications. Although maximum power to the load is always desired, most converters only take electrical efficiency into consideration. However, not only the electrical efficiency must be considered, but the mechanical energy as well. If the converter is designed to look like a purely resistive load and not a switched load, a wind turbine is able to supply the maximum power with lower conduction loss at the input side due to high current spikes. Two power converters, VIENNA with buck converter and a Buck-boost converter, were designed and experimentally analyzed. A unique approach of controlling the MPPT algorithm through a conductance G for PFC is proposed and applied in the VIENNA topology. On the other hand, the Buck-boost only operates MPPT. With the same wind profile applied for both converters, an increase in power drawn from the input increased when PFC was used even when the power level was low. Both topologies present their own unique advantages. The main advantage for the VIENNA converter is that PFC allowed more power extraction from the turbine, increasing both electrical and mechanical efficiency. The buck-boost converter, on the other hand, presents a very low component count which decreases the overall cost and volume. Therefore, a small, cost-effective converter that maximizes the power transfer from a small power wind turbine to a DC load, can motivate consumers to utilize the power available from the wind.
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Date Issued: 2009
Identifier: CFE0002730, ucf:48158
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0002730

Title: LDMOS Power Transistor Design and Evaluation using 2D and 3D Device Simulation.
Creator: Salih, Aiman, Yuan, Jiann-Shiun, Sundaram, Kalpathy, Kapoor, Vikram, University of Central Florida
Abstract / Description: The benefit of the super-junction (SJ) technique and the use of a floating P layer for low voltage (30 V) laterally double-diffused metal oxide semiconductor (LDMOS) transistors are investigated in this thesis using Sentaurus TCAD simulation software. Optimizations to the SJ LDMOS were attempted such as adding a buffer layer to the device, but simulation and theoretical evidence point out that the benefits of the SJ technique are marginal at the 30 V application. A replacement for the SJ...
Show moreThe benefit of the super-junction (SJ) technique and the use of a floating P layer for low voltage (30 V) laterally double-diffused metal oxide semiconductor (LDMOS) transistors are investigated in this thesis using Sentaurus TCAD simulation software. Optimizations to the SJ LDMOS were attempted such as adding a buffer layer to the device, but simulation and theoretical evidence point out that the benefits of the SJ technique are marginal at the 30 V application. A replacement for the SJ technique was sought, the floating P structure proved to be a good solution at the low voltage range due to its simpler cost effective process and performance gains achieved with optimization. A new idea of combining the floating P layer with shallow trench isolation is simulated yielding a low figure of merit (on state resistance (&)#215; gate charge) of 5.93 m?-nC.
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Date Issued: 2017
Identifier: CFE0006955, ucf:51673
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006955

Title: PROTOTYPE OF COUPLING UNIT NETWORK FOR POWER LINE COMMUNICATIONS.
Creator: Srinivasan, Bharath, Wei, Lei, University of Central Florida
Abstract / Description: Power Line Communications has made impressive strides since its introduction. Power Line Communications (PLC) or Broadband over Power Lines (BPL) is the method of transmitting broadband signals over the power lines and making it available at the power outlet in homes. It provides last mile communication and makes use of existing power lines to transmit signals, thereby eliminating the need to lay cables all over again. PLC is fast becoming a commercial reality in the United States. The...
Show morePower Line Communications has made impressive strides since its introduction. Power Line Communications (PLC) or Broadband over Power Lines (BPL) is the method of transmitting broadband signals over the power lines and making it available at the power outlet in homes. It provides last mile communication and makes use of existing power lines to transmit signals, thereby eliminating the need to lay cables all over again. PLC is fast becoming a commercial reality in the United States. The Federal Communications Commission (FCC) is working toward making PLC a standard with particular emphasis on power emission issues and interference with nearby bands. Power companies, vendors and ISPs (Internet Service Providers) have tied up to bring this new technology to market. The Power line environment is inherently unpredictable due to interference, low signaling impedance and the highly linear operating environment that PLC transmitters require. The coupling unit in the PLC system acts as a filter and eliminates the harmful AC signal from interfering with the broadband signals. A coupling unit amplifier topology that provides gain equalization and wideband mitigation to the effects of low-impedance loads on PLC in the high frequency range has been explored in detail in this study. The amplifier is verified for its performance by means of circuit simulation using industry-standard software such as Agilent's Advanced Design System (ADS). The coupling unit has also been fabricated to verify the performance. An experimental setup for verifying the performance of the coupling unit using a PLC transmitter and PLC receiver has also been proposed.
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Date Issued: 2006
Identifier: CFE0001306, ucf:47029
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001306

Title: EFFECT OF INNER SCALE ATMOSPHERIC SPECTRUM MODELS ON SCINTILLATION IN ALL OPTICAL TURBULENCE REGIMES.
Creator: Mayer, Kenneth, Young, Cynthia, University of Central Florida
Abstract / Description: Experimental studies have shown that a "bump" occurs in the atmospheric spectrum just prior to turbulence cell dissipation.1,3,4 In weak optical turbulence, this bump affects calculated scintillation. The purpose of this thesis was to determine if a "non-bump" atmospheric power spectrum can be used to model scintillation for plane waves and spherical waves in moderate to strong optical turbulence regimes. Scintillation expressions were developed from an "effective" von Karman spectrum using...
Show moreExperimental studies have shown that a "bump" occurs in the atmospheric spectrum just prior to turbulence cell dissipation.1,3,4 In weak optical turbulence, this bump affects calculated scintillation. The purpose of this thesis was to determine if a "non-bump" atmospheric power spectrum can be used to model scintillation for plane waves and spherical waves in moderate to strong optical turbulence regimes. Scintillation expressions were developed from an "effective" von Karman spectrum using an approach similar to that used by Andrews et al.8,14,15 in developing expressions from an "effective" modified (bump) spectrum. The effective spectrum extends the Rytov approximation into all optical turbulence regimes using filter functions to eliminate mid-range turbulent cell size effects to the scintillation index. Filter cutoffs were established by matching to known weak and saturated scintillation results. The resulting new expressions track those derived from the effective bump spectrum fairly closely. In extremely strong turbulence, differences are minimal.
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Date Issued: 2007
Identifier: CFE0001559, ucf:47141
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001559

Title: BI-DIRECTIONAL DCM DC-TO-DC CONVERTER FOR HYBRID ELECTRIC VEHICLES.
Creator: Pepper, Michael, Batarseh, Issa, University of Central Florida
Abstract / Description: With the recent revival of the hybrid vehicle much advancement in power management has been made. The most popular hybrid vehicle, the hybrid electric vehicle, has many topologies developed to realize this hybrid vehicle. From these topologies, as sub set was created to define a particular group of vehicles where the converter discussed in this thesis has the most advantage. This sub set is defined by two electric sources of power coupled together at a common bus. This set up presents many...
Show moreWith the recent revival of the hybrid vehicle much advancement in power management has been made. The most popular hybrid vehicle, the hybrid electric vehicle, has many topologies developed to realize this hybrid vehicle. From these topologies, as sub set was created to define a particular group of vehicles where the converter discussed in this thesis has the most advantage. This sub set is defined by two electric sources of power coupled together at a common bus. This set up presents many unique operating conditions which can be handled seamlessly by the DC-to-DC converter when designed properly. The DC-to-DC converter discussed in this thesis is operated in Discontinuous Conduction Mode (DCM) of operation because of its unique advantages over the Continuous Conduction Mode (CCM) operated converter. The most relevant being the reduction of size of the magnetic components such as inductor, capacitor and transformers. However, the DC-to-DC converter operated in DCM does not have the inherent capability of bi-directional power flow. This problem can be overcome with a unique digital control technique developed here. The control is developed in a hierarchical fashion to separate the functions required for this sub set of hybrid electric vehicle topologies. This layered approach for the controller allows for the seamless integration of this converter into the vehicle. The first and lowest level of control includes a group of voltage and controller regulators. The average and small signal model of these controllers were developed here to be stable and have a relatively fast recovery time to handle the transient dynamics of the vehicle system. The second level of control commands and organizes the regulators from the first level of control to perform high level task that is more specific to the operation of the vehicle. This level of control is divided into three modes called hybrid boost, hybrid buck and electric vehicle mode. These modes are developed to handle the specific operating conditions found when the vehicle is operated in the specific mode. The third level of control is used to command the second level of control and is left opened via a communication area network (CAN) bus controller. This level of control is intended to come from the vehicle's system controller. Because the DC-to-DC converter is operated in DCM, this introduces added voltage ripple on the output voltage as well as higher current ripple demand from the input voltage. Since this is generally undesirable, the converter is split into three phases and properly interleaved. The interleaving operation is used to counteract the effects of the added voltage and current ripple. Finally, a level of protection is added to protect the converter and surrounding components from harm. All protection is designed and implemented digitally in DSP.
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Date Issued: 2008
Identifier: CFE0002496, ucf:47676
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0002496

Title: MINIMIZATION OF POWER DISSIPATION IN DIGITAL CIRCUITS USING PIPELINING AND A STUDY OF CLOCK GATING TECHNIQUE.
Creator: Panchangam, Ranganath, Yuan, Jiann, University of Central Florida
Abstract / Description: Power dissipation is one of the major design issues of digital circuits. The power dissipated by a circuit affects its speed and performance. Multiplier is one of the most commonly used circuits in the digital devices. There are various types of multipliers available depending upon the application in which they are used. In the present thesis report, the importance of power dissipation in today's digital technology is discussed and the various types and sources of power dissipation have been...
Show morePower dissipation is one of the major design issues of digital circuits. The power dissipated by a circuit affects its speed and performance. Multiplier is one of the most commonly used circuits in the digital devices. There are various types of multipliers available depending upon the application in which they are used. In the present thesis report, the importance of power dissipation in today's digital technology is discussed and the various types and sources of power dissipation have been elaborated. Different types of multipliers have been designed which vary in their structure and amount of power dissipation. The concept of pipelining is explained and the reduction in the power dissipation of the multipliers after pipelining is experimentally determined. Clock gating is a very important technique used in the design of digital circuits to reduce power dissipation. Various types of clock gating techniques have been presented as a case study. The technology used in the simulation of these circuits is 0.35µm CMOS and the simulator used is SPECTRE S.
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Date Issued: 2004
Identifier: CFE0000130, ucf:46207
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0000130

Title: Minimal Effects of Moderate Normobaric Hypoxia on the Upper-Body Work-Time Relationship in Recreationally-Active Women.
Creator: Starling-Smith, Tristan, Fukuda, David, Stout, Jeffrey, Wells, Adam, University of Central Florida
Abstract / Description: INTRODUCTION: Hypoxic training protocols vary with respect to exercise modality and intensity. Variables derived from the work-time relationship, namely critical power (CP) and anaerobic working capacity (W'), have been previously examined during upper and lower-body exercise in hypoxia. However, these studies have neglected to examine women who reportedly exhibit different responses to exercise in hypoxia compared to men.PURPOSE: To evaluate the effects of moderate normobaric hypoxia on the...
Show moreINTRODUCTION: Hypoxic training protocols vary with respect to exercise modality and intensity. Variables derived from the work-time relationship, namely critical power (CP) and anaerobic working capacity (W'), have been previously examined during upper and lower-body exercise in hypoxia. However, these studies have neglected to examine women who reportedly exhibit different responses to exercise in hypoxia compared to men.PURPOSE: To evaluate the effects of moderate normobaric hypoxia on the parameters of the work-time relationship during upper body exercise in women. METHODS: Thirteen recreationally active women (age: 22.7 (&)#177; 2.6 y; height: 167 (&)#177; 8.6 cm; weight: 66.4 (&)#177; 9.7 kg; body fat: 27.6 (&)#177; 5% body fat) completed a graded exercise test in both normobaric hypoxia (H; FiO2=~14%) and normoxia (N; FiO2=~20%) to exhaustion on an arm ergometer to determine V?O2peak and peak power output (PPO). Each participant completed four constant work-rate arm-cranking tests at 90-120% PPO in both environmental conditions. Linear regression was used to estimate CP and AWC via the work-time relationship during the constant work-rate tests. Paired samples t tests compared mean differences between V?O2peak, PPO, CP and AWC between conditions (N vs. H). Two-way (condition (&)#215; intensity) repeated measures ANOVA was used to compare total work and time-to-exhaustion.RESULTS: H significantly reduced VO2peak (N: 1.73L/min (&)#177; .31L/min vs. H: 1.62L/min (&)#177; .27L/min, p=.008) but had minimal effects on PPO (N: 78.08W(&)#177;14.51W vs. H: 75.38W(&)#177;13.46, p=.089), CP (N: 57.44W(&)#177;18.89W vs. H: 56.01W(&)#177;12.36W, p=.546), and AWC (N: 4.81kJ(&)#177;1.01kJ vs. H: 4.56kJ(&)#177;.91kJ, p=.510). No significant condition (&)#215; intensity interactions were noted for total work or time-to-exhaustion (p(>).05). CONCLUSIONS: Moderate normobaric hypoxia significantly reduced VO2peak but had minimal effects on CP and AWC using the work-time model
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Date Issued: 2018
Identifier: CFE0007248, ucf:52184
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007248

Title: Critical Exposure Pathways: An Analysis of the Environmental Impact of Gaseous Effluents from Light-Water-Cooled Reactors.
Creator: Danna, Robert, McLellon, Waldron M., Engineering
Abstract / Description: University of Central Florida College of Engineering Thesis; The analysis of the environmental impact of routine radioactive gaseous releases from operating nuclear power stations is discussed using a radiation dose assessment. This analysis includes a discussion of the origin of radionuclide effluents, a discussion of federal policies, and a calculation of radiation doses to man. A model of estimating the radioactive dose from gaseous effluents from light-water-cooled reactors is described...
Show moreUniversity of Central Florida College of Engineering Thesis; The analysis of the environmental impact of routine radioactive gaseous releases from operating nuclear power stations is discussed using a radiation dose assessment. This analysis includes a discussion of the origin of radionuclide effluents, a discussion of federal policies, and a calculation of radiation doses to man. A model of estimating the radioactive dose from gaseous effluents from light-water-cooled reactors is described using guidelines described in the Code of Federal Regulations and the Nuclear Regulatory Commission's Regulatory Guides. The environmental impact of these sources is then analyzed using dose rates calculated along critical exposure pathways for various radioactive nuclides. Examples are given using ractors that have been heretofore documented in the literature. the major radionuclides in the airborne effluents from a PWR, used as an example are noble gases, H-3, radioiodines, and radioactive particles. The results from the methodologies described in this paper are compared to federal radiation limits
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Date Issued: 1979
Identifier: CFR0008134, ucf:52949
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFR0008134

Title: Super-adiabatic combustion in porous media with catalytic enhancement for thermoelectric power conversion.
Creator: Mueller, Kyle, Orlovskaya, Nina, Chen, Ruey-Hung, Kapat, Jayanta, University of Central Florida
Abstract / Description: The combustion of ultra-lean fuel to air mixtures provides an efficient way to convert the chemical energy of hydrocarbons into useful power. Conventional burning techniques of a mixture have defined flammability limits beyond which a flame cannot self-propagate due to heat losses. Matrix stabilized porous medium combustion is an advanced technique in which a solid porous matrix within the combustion chamber accumulates heat from the hot gaseous products and preheats incoming reactants. This...
Show moreThe combustion of ultra-lean fuel to air mixtures provides an efficient way to convert the chemical energy of hydrocarbons into useful power. Conventional burning techniques of a mixture have defined flammability limits beyond which a flame cannot self-propagate due to heat losses. Matrix stabilized porous medium combustion is an advanced technique in which a solid porous matrix within the combustion chamber accumulates heat from the hot gaseous products and preheats incoming reactants. This heat recirculation extends the standard flammability limits and allows the burning of ultra-lean fuel mixtures, conserving energy resources, or the burning of gases of low calorific value, utilizing otherwise wasted resources. The heat generated by the porous burner can be harvested with thermoelectric devices for a reliable method of generating electricity for portable electronic devices by the burning of otherwise noncombustible mixtures.The design of the porous media burner, its assembly and testing are presented. Highly porous (~80% porosity) alumina foam was used as the central media and alumina honeycomb structure was used as an inlet for fuel and an outlet for products of the methane-air combustion. The upstream and downstream honeycomb structures were designed with pore sizes smaller than the flame quenching distance, preventing the flame from propagating outside of the central section. Experimental results include measurements from thermocouples distributed throughout the burner and on each side of the thermoelectric module along with associated current, voltage and power outputs. Measurements of the burner with catalytic coating were obtained for stoichiometric and lean mixtures and compared to the results obtained from the catalytically inert matrix, showing the effect on overall efficiency for the combustion of fuel-lean mixtures.
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Date Issued: 2011
Identifier: CFE0004142, ucf:49043
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004142

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