Browsing by Subject "Electric"
Now showing 1 - 10 of 10
Results Per Page
Sort Options
Item A critical path based parametric ring oscillator(Texas Tech University, 2000-12) Black, Todd A.This paper details the design and verification of a new type of semiconductor parametric oscillator. The oscillator will be designed to incorporate a close representation of the actual critical path of the device being tested. The oscillator will allow for more accurate modeling of device speed, leading to improvements in yield analysis and material planning. The oscillator is designed for an advanced CMOS process to model a complex microprocessor.Item Alternator analysis for pulsating loads(Texas Tech University, 1978-05) Lee, Chung-ShingNot availableItem Controlling neural cell behavior with electric field stimulation across a conductive substrate(2012-12) Nguyen, Hieu Trung 1980-; Schmidt, Christine E.Electrical stimulation of tissues induces cell alignment, directed migration, extended processes, differentiation, and proliferation, but the mechanisms involved remain largely unknown. To reveal effects of electric fields (EF) through the media on cell behavior, voltage (7.45 – 22 V), current density (36 – 106 mA/cm2), duration (2 – 24 hrs), and alternating currents (AC, 2 – 1000 Hz) were varied independently when exposed to cell cultures. It was determined that current density and duration are the primary attribute Schwann cells respond to when an EF is applied through the media. This implies that the number of charges moving across the cell surface may play a key role in EF-induced changes in cell behavior. Identical conditions were used to stimulate cells grown on the surface of a conductive substrate to examine if a scaffold can provide structural and EF cues. The effects of an EF through the substrate were examined by placing a protein gel on the surface during stimulation and observing the morphology of subsequent cell cultures and the physical topology of the gel. EFs were shown to create Ca2+ redistribution across gels and subtle changes in collagen I fibril banding. Stimulated gels were able to induce perpendicular Schwann cell alignment on newly seeded cultures days after initial EF exposure, and the cell response decreased when seeded at longer times, indicating the effects of EF on the matrix environment has a relaxation time. These findings were then integrated into a biodegradable, electrically conductive polypyrrole-poly-ε-caprolactone polymer developed by collaborators. Dorsal root ganglia placed in matrix gels on top of conducting polymer exhibited significantly longer axons when stimulated with DC and AC signals. The overall results demonstrate that EFs have a significant effect on the extracellular environment. The broad implication of this data grants researchers with the ability to physically and metabolically control cell behavior with EFs, including improved wound healing or reduced cancer metastasis.Item Deposition, Diagenesis, and Porosity Relationships of the Lower San Andres Formation, Quay and Roosevelt Counties, New Mexico(Texas Tech University, 1979-05) Worthen, John AldrichNot Available.Item Drivers of environmentally-friendly technology adoption : electric vehicle and residential solar PV adoption in California(2016-05) Nath, Vivek; Rai, Varun; Zarnikau, JayThe use of electric vehicles (EVs) and residential solar photovoltaic (PV) panels is expected to play a role in stabilizing greenhouse gas concentrations in the atmosphere within an acceptable range, to mitigate detrimental climate change impacts. This thesis uses two uniquely rich datasets from the EV and residential solar PV market in California to study the demographic, motivational, social and informational influences on technology adoption decision-making. Rogers’ diffusion of innovations theory and the theory of planned behavior (TPB) are extensively used to contextualize the findings. Several findings aligned with Rogers’ generalizations regarding communication channels and characteristics of earlier adopters, and the increasing role of interpersonal communication channels signaled a shift to the early majority. Strong support was also found for the theory of planned behavior through the identification of the role of personal norms, subjective norms, attitude, and perceived behavioral control on intention and, ultimately, behavior. Information channels used by the EV cohort suggest a possible departure from TPB through the role of habitual behavior and attitudinal formation.Item Feasibility of variable frequency speed control for irrigation wells(Texas Tech University, 1983-12) Hendrick, Levi KyleNot availableItem Multi-speed electric hub drive wheel design(2013-08) Woodard, Timothy Paul; Tesar, DelbertAdvances in electro-mechanical actuation have encouraged revolutions in automobile design which promise to increase fuel efficiency, reduce costs, improve safety and performance, and allow a wider range of architectural choices for the vehicle designer and manufacturer. This is facilitated by the concept of an intelligent corner (IC). The IC consists of traction, steering, camber, and suspension actuators working together to control the forces generated at the wheel/surface interface, allowing complete control of vehicle motion with completely active, as opposed to passive, systems. The most critical actuator to the longitudinal performance of an IC vehicle is the traction system, envisioned in this case as a hub mounted electro-mechanical actuator connected directly to the wheel. This traction actuator consists of a number of primary and supplementary components, including a prime mover, gear train, clutch, brake, bearings, seals, shafts, housing, etc. The consideration of these components in the design of an in-hub electric drive actuator is the subject of this report. Currently, gear trains are used in automobiles to match the operating speed of an internal combustion engine (ICE) to the speed of the vehicle on the road. The same need is anticipated for the hub drive wheel, although with fewer reduction ratio choices due to the responsiveness of the electric motor. Specifying a gear train design includes selecting a gear train architecture, and designing the gears to handle the expected loads. A review of gear design and gear train architectures is presented. A number of electric machines are used in industrial, and now more commonly, vehicle applications; of these, the switched reluctance motor (SRM) represents an excellent candidate for a vehicle prime mover due to its ruggedness, broad torque speed curve, low cost, and simplicity. Integrating the motor and gear train into an electro-mechanical actuator with multiple speeds requires consideration of other ancillary components. Brief design guides are presented for clutches, brakes, bearings, seals, and the structure for the in-hub wheel drive. Given the analytical descriptions of the drive wheel components, methods for managing the numerous design parameters are developed and expanded. Actuator specifications are chosen based upon meeting various vehicle performance requirements such as maximum speed, gradeability, acceleration, and drawbar pull. A proposed parametric drive wheel design is presented to meet the requirements of a generic heavy vehicle. The design demonstrates the feasibility of actuator technology that can be used to increase the performance, maintainability, and refreshability of hybrid electric vehicles while allowing open architecture paradigms to lower costs and spur new levels of manufacturing and innovation.Item Multiphase flow application to ESP pump design program(Texas Tech University, 1996-05) Carrascal, Jorge FernandoThe exploitation of a hydrocarbon reservoir may involve the flow of liquids and gases together. The simultaneous flow of these fluids is called multiphase flow. During the production process, the produced fluids are submitted to changes in pressure and temperature. As a result of these changes in pressure and temperature, the fluids physical properties change. The changes in volume of the liquid systems are due to gas liberation, reduction in pressure, and reduction in temperature. Viscosity, surface tension, and other physical properties are functions of pressure and temperature. Therefore, these properties are different for different conditions. The design of well artificial lifr systems and well completion strings involves the calculation of pressure gradients. The determination of these pressures gradients requires the use of in-situ rates and the knowledge of the different fluid physical properties. Finding the value of the pressure gradients for multiphase flow is not easy. The reason for this is that the simultaneous flow of gases and liquids involves slippage between the phases. This slippage involves transfer of energy from gases to liquids and to the surroundings. An analytical solution does not exist. Therefore, the use of empirical correlations is necessary. Additionally, the PVT analysis from the fluids is not always available, and again, the use of empirical correlations for the determination of these properties is necessary. ESPs are designed to lift water. Operators and pump companies do not account for the estimation of pressure losses for multiphase flow nor the in-situ volumetric flow rates for the selection design of these pumps. The purpose of this thesis is the application of correlations for estimation of pressure losses in multiphase flow and the use of in-situ volumetric flow rates for the calculations of selection design for ESPs. A computer program that contains these correlations was translated from FORTRAN to Basic. Three topics in the literature review are covered. These topics comprise multiphase flow methods, PVT relationships and generalities about ESPs. Chapter 2 is a review of multiphase flow correlations. The methods by Hagedom and Brown, Duns and Ros, Beggs and Brill, and Orkiszewski are discussed. Chapter 3 covers the different fluid physical properties. PVT correlations are presented. A set of references about the different correlations is provided. Chapter 4 covers information of ESPs. This information is about the ESP system, typical installation, ESP system components, selection data and method, and troubleshooting. Chapter 5 presents information about the computer program that was translated. Information such as some small changes in the original program, a flow diagram for the determination of pressure traverse, why the change from FORTRAN to BASIC was made, problems in the translation, and results are covered. Chapter 6 finishes with some conclusions about the project in general and presents some recommendations for future work.Item Stability in the Series-Tuned Colpitts Oscillator: A Thesis in Electrical Engineering(Texas Tech University, 1951-02) Combs, Samuel ANot Available.Item The effect of household life-cycle stages, poverty, and demographic characteristics on rental expenditures(Texas Tech University, 1997-05) Lokken, Sheri LynnRent-to-own outlets market to the poor. There is a lack of scholarly research on rental expenditures of consumers across the household life cycle. The purpose of this study was to investigate the value of the household life cycle as an indicator of the allocation of rental expenditures by families. This study also examined the effect of poverty, ethnicity, family size, and education on rental expenditures. Rental expenditures on furniture, audio visual equipment, and appliances, as reported by the 1992 Consumer Expenditure Interview Survey, were the focus of this study. A sample size of 25,953 households was used. A total of 307 occurrences of renting appliances, furniture, and audio visual equipment representing 171 households was provided. An Analysis of Variance (ANOVA) was used to examine whether the rental expenditure means were significantly different among household lifecycle categories. An ANOVA was also used to investigate whether the rental expenditure means were significantly different among categories for poverty, household life cycle, family size, family type, education, and ethnicity. Multiple regression techniques were used to analyze whether the household life-cycle variable was a more valuable indicator of rental expenditures than ethnicity, poverty, education, income, or family size. This study offers further research to support the fact that consumers in poverty and consumers with lower levels of education are more likely to rent appliances and audio visual equipment. The rental of audio visual equipment was found to be generally decreasing across the household life cycle. The results of this study also found that the household life cycle is a valuable indicator of the allocation of rental expenditures by families. Implications for government, education, and business are discussed.