Hybrid Aircraft Propulsion System Synthesis (HAPSS) is a computer program that sizes and analyzes pure-series hybrid electric propulsion systems for aircraft. The development of this program began during a NASA SBIR contract, in conjunction with Empirical Systems Aerospace (ESAero), with the creation of a propulsion fan design tool. Since the completion of this contract in July 2010, the HAPSS program has been expanded to combine the many aspects of a hybrid propulsion system such as the propulsive fans, electric motors, generators, and controllers, and the internal combustion engines. This thesis describes the benefits and drawbacks of aircraft hybrid propulsion systems to reveal the usefulness of a program of this nature. The methodology behind HAPSS, the creation of the program, its operation, and its many applications are also discussed in detail. Finally, this thesis includes a brief example in which HAPSS is used to analyze a hybrid propulsion system for a commercial transport aircraft. This example demonstrated the usefulness of the program and revealed interesting behavior and trends unique to hybrid propulsion. To date, the HAPSS program has been utilized on several different contract projects in which an aircraft hybrid propulsion system was designed. In the summer of 2012, a government organization in conjunction with ESAero will begin funding a contract to continue the development of HAPSS by adding functionality and improving accuracy while making the tool available to other government agencies.

Experiments were conducted on the Cal Poly air augmented rocket (AAR) in order to characterize two-dimensional flowfield phenomenon occurring in the mixing duct. The testing utilized a direct connect system where high pressure nitrogen is fed into the combustion chamber, to form a primary flow. The high pressure nitrogen is then expanded through a nozzle, with an area ratio of 22 and an exit area of 0.75 in2, up to Mach 4.3. Secondary air is entrained from a plenum chamber which is used to create a lower stagnation pressure for the secondary flow. The two flows mix in a duct that has a cross sectional area of 2.06 in2. The maximum pressure ratio, the ratio of primary to secondary stagnation pressure, achieved during testing was 132. The stagnation pressures of the primary and secondary flows are transient throughout the test. The quasi-steady portion of each run increased with increasing pressure ratio. Pressure and temperature measurements were collected from ten test runs. Shadowgraph images were taken of the mixing duct during testing in order to image the interactions between the primary and secondary flows. The images show an oblique shock forming in the primary flow. The angle of the shock matches theoretical predictions to within 8.41%. The oblique shock begins at a distance of 1.5 inches downstream of nozzle exit when the AAR is operating in the Fabri choked condition. The images also show the mixing region which forms between the primary and secondary flows. The mixing region represents as much as 25% of the cross-sectional area of the flow field in the mixing duct two inches downstream of the nozzle exit. An analysis of the secondary Mach number in the mixing duct shows that Fabri choking is occurring during testing. The secondary Mach number decreases as pressure ratio increases, in the Fabri choked condition. The transition to Fabri choking occurs at a pressure ratio of 100, suggesting that this is the pressure ratio of the saturated case. The shape of the primary plume was compared to results from a 2-D simulation developed to predict the flow field inside the Cal Poly AAR. Although, the simulation is unable to predict the entire flowfield, modifications made it able to predict the velocity of the secondary, entrained, flow within 3.7%. The modified simulation also predicts the that the primary plume will have expanded 98% of its total distance from the centerline of the mixing duct 1.7 inches downstream of the primary nozzle exit. Pressure data taken along the wall of the mixing duct was used to identify the location of Fabri choking in the mixing duct. Tests showed that Fabri choking is occurring between 1 inch and 2.5 inches downstream of the nozzle exit. The location of Fabri choking moves farther downstream of the nozzle as pressure ratio increases.

The power requirements for the microprocessor have been increasing as per Moore's Law. According to International Technology Roadmap (ITRS), the Voltage Regulator Module (VRM) for the microprocessor will be 200 W(with 1V, 200A output) in 2010. With the VRMs topology of synchronous buck, serious technical challenges such as small duty cycle, high switching frequencies, and higher current demands, contribute to decreased power density and increased cost. This thesis proposes a Multiphase Multi-Interleave Buck topology to solve the technical challenges of powering future microprocessors. The critical design parameter values are selected using the theoretical design equations and calculations. The design is simulated in OrCAD Pspice to evaluate the performance criteria of the VRM. A prototype of four-phase Multiphase Multi-Interleave Buck Converter is constructed. The critical performance parameters of the prototype are tested and measured. The thesis concludes with the performance of the prototype as compared with the performance of the design simulation.

In this study, a standard bulk FET design is fabricated with a piezoelectric gate, allowing a microwave-frequency voltage signal to be transmitted from a transducer to the transistor via acoustic conduction through the substrate. Using a single polycrystalline aluminum nitride film as the piezoelectric material, microwave-frequency piezoelectric transducers were fabricated in parallel with piezoelectric FETs. These device pairs function by generating high frequency acoustic waves in the substrate via application of AC voltage to the transducers; the transistors then recover these signals by detecting these waves in their gates via the piezoelectric film, reproducing an attenuated version of the original voltage signal. By taking advantage of the active nature of the transistor and properly controlling the gate and drain bias voltages to maximize gain, the signal recovered by the transistor can be amplified beyond what is passively recovered. In this paper, the design, fabrication, and testing processes for these devices are described at length; the results of these processes, demonstrating devices equivalent to standard FETs that are capable of harnessing incident acoustic waves to generate AC voltages at microwave frequencies, are also presented.

According to the US Energy and Information Administration, between 2022-2023 60% of planned new electricity generation consists of solar farms with a battery energy storage system [1]. The demand for these paired systems has increased since batteries can be charged during the day with the energy captured from the solar farm then released to the customer in the evening during peak energy demand. This achieves peak load shaving which reduces the cost of electricity for the customer and is ecologically friendly. This thesis aims to create an efficient solar farm with a battery energy storage system for a farmer in California that achieves peak load shaving. Full cell modules and half-cell modules were explored to determine the type that best suits this project. The half-cell modules were best suited because of the increased efficiency. Six different solar farm designs were created, four fixed tilt designs and two single axis tracking designs. Two types of software, System Advisor Model (SAM) and REopt, were compared to determine which would be most useful in simulating these designs. It was concluded that System Advisor Model (SAM) would be the most accurate to simulate the six designs and produce metrics such as the annual energy production, capacity factor, DC to AC ratio, and levelized cost of energy. The final design, design 6, a 2-string single axis tracking design produced the best metrics that met the project requirements and a battery energy storage system was sized for the design.

The use of renewable energy and specifically solar energy in power systems is rapidly increasing due to significantly lower carbon emissions and low energy costs. Although the widespread use of renewable energy generation provides many benefits to the power system, high levels of renewable energy generation introduce several new challenges to the power system operation. The high level of uncertainty associated with solar power output complicates operation and planning decisions for the power system. Therefore, accurate and reliable solar power forecasts are needed for the planning and operation of the power system more than ever before. This thesis first focuses on improving probabilistic solar power forecasts that provide detailed information on the uncertainty of the forecasts. The proposed copula-based Bayesian method utilizes the underlying relation between temperature and solar power output to improve forecast accuracy and performance. The results show significant improvement compared to the direct use of temperature as an input to the forecast model. Secondly, a novel improvement is made to the State Frequency Memory (SFM) method for solar forecasting. The SFM model, which is based on the Long Short Term Memory (LSTM) method, incorporates the patterns in the frequency domain on top of the time domain considerations. The SFM model is improved by frequency band selection based on the Fourier transform of the solar power data. The improved SFM model is able to include the low-frequency patterns in solar data compared to the sampling frequency of second and minute-level and significantly improve results in very short-term forecasting. Thirdly, One of the challenges that arise from high penetration of solar power is investigated further. An essential part of power system operation is maintaining the balance between generation and loads in the power system. The intermittency of solar power makes it very challenging for the operators to maintain the balance and increases the need for spinning reserves in the power system. In this thesis, solar forecasts are used in a multistep optimization model to control energy storage and electric vehicle charging to minimize violations from the ramp rate limits of the system. A detailed analysis of forecast error is performed to tackle the trade-off between longer forecast horizons and increasing forecast error and find the optimal forecast horizon for predictive solar power smoothing.

This study was designed to explore the importance a pet can have on someone's life, including ways a pet affects the relationships an individual has with other family members. This study assessed how pets can be influential in people's lives, especially with regard to the cultivation of family relationships and the development and maintenance of emotional stability. The opinions of pet owners were reviewed with regard to whether they felt their pets loved them and considered a family member. Also evaluated was how a relationship with one's pet might have been similar to any other relationship within one's family, along with the extent one's pet added harmony or discomfort to family relationships.The following research questions guided this exploratory and qualitative study: (a) In what ways can a pet influence a person's life regarding family relationships? (b) In what ways can a pet replace or act as a beneficial substitute for other interpersonal and significant relationships? Specific attention was paid to how pets affect individuals in their family and various relationships between the family members, including the different roles the pet plays within family circumstances.An open-ended, 12-question survey was distributed to six undergraduate classes, two at Radford University and four at Virginia Polytechnic Institute and State University. Individuals identified different pets in their lives, and in some cases, described several positive attributes about their pets in the context of a personal anecdote about their pets and certain family relationships.The results of this study showed that pets are an important aspect to many families, and in several cases represent another "family member," or another "sister or brother." Pets often serve as a relief of distress for families by listening to verbal behavior, providing a best friend, encouraging family bonding, and acting as a protector. / Master of Science

With the growing concerns of climate change due to fossil fuel-based electricity generation, solar integration to the grid is swiftly increasing. However, the intermittency of solar power is a major obstacle to harness it efficiently. Energy storage system (ESS) with its declining price over the last few years is a viable solution to address this issue. Another source of greenhouse gas emission is fossil fuel-based transportation system which is likely to be replaced by electric vehicles (EVs) in near future. To match the driving range of EVs with the internal combustion engine-based vehicle, fast and extreme fast charging infrastructure in terms of power electronics and control must be developed. Utilization of multiport converters in both applications (EV charging and grid-connected solar+ESS) ensures higher efficiency, higher power density and improved reliability owing to the reduced number of power stages. This dissertation discusses multiport converter design and its control method for photovoltaic (PV) and EV applications. A system-level model predictive control (MPC) for a grid-connected ESS system with PV and load is developed to smooth the PV intermittency and improve ESS lifetime. Also, power electronic circuit level MPC guarantees real and reactive power control, output voltage regulation, and maximum power point tracking. Furthermore, a comprehensive review of converter topologies is carried out which leads to the selection of the dual active bridge (DAB) dc-dc converter as the fundamental power conversion unit. DAB topology is well-suited for its high efficiency, high power density, bidirectionality, soft switching, isolation, and wide range of voltage transfer ratio. Adding a resonant tank (LC or CLLLC) in the DAB configuration results in lower conduction loss and extended soft switching range. A three-port dc-dc-dc converter based on DAB with LC & CLLLC resonant tank has been introduced that integrates EV battery, PV, and dc-link for EV fast charging.

ITC/USA 2006 Conference Proceedings / The Forty-Second Annual International Telemetering Conference and Technical Exhibition / October 23-26, 2006 / Town and Country Resort & Convention Center, San Diego, California / This paper will present methods to both measure the unmodulated carrier power of a modulated signal and to estimate the unmodulated carrier power level from the measured power spectrum. The unmodulated carrier power level is needed to convert measured spectra into units of dBc.

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