Indiana University-Purdue University Indianapolis (IUPUI) / In the present work, we consider a class of Finsler metrics using the warped product notion introduced by B. Chen, Z. Shen and L. Zhao (2018), with another “warping”, one that is consistent with the form of metrics modeling static spacetimes and simplified by spherical symmetry over spatial coordinates, which emerged from the Schwarzschild metric in isotropic coordinates. We will give the PDE characterization for the proposed metrics to be Ricci-flat and construct explicit examples. Whenever possible, we describe both positive-definite solutions and solutions with Lorentz signature. For the latter, the 4-dimensional metrics may also be studied as Finsler spacetimes.

This diploma work is dealing with the design of a multifunctional complex. These are two buildings on plot number 8618 on cat. the territory of the city of Trnava. The technical background of the buildings and hygiene background for employees are designed in the buildings. Vertical support structures are from ceramic blocks. Horizontal support structures are designed as reinforced concrete monolithic. The construction is based on the foundation strips. The roofing of the buildings is performed by a single-coated area non-permitable roof

Thermoelectric generator (TEG) is a solid state technology based on the Seebeck effect that can generate electrical power from waste heat. For continuous electrical power generation heat exchangers are integrated into the “cold side” and the “hot side” of the TEG such that a temperature difference across the TEG can be established and maintained. This thesis will focus on characterizing two different flat-plate cold side heat exchanger prototypes specifically designed for dissipating the thermal loads from TEG modules. The majority of TEGs modules available have a flat geometry design and a square shape with typical dimension of 40 mm × 40 mm or 56 mm × 56 mm. To maximize the net electrical power generated by the TEGs the cold side heat exchanger is required to have uniform surface temperature distribution, and excellent heat transfer performance with minimum pressure drop. To achieve the previously mentioned requirements, two flat-plate heat exchanger prototypes having two distinct heat transfer techniques were investigated. Each heat exchanger is designed to accommodate an array of 14 TEG modules arranged in two parallel rows with 7 TEGs per row a typical arrangement for large waste energy harvesting applications. The first heat exchanger prototype utilized single-phase forced convection through 140 minichannels (1 mm × 1 mm × 90 mm long) as a heat transfer technique. The second prototype utilized 14 liquid jets, 3 mm in diameter and 40.3 mm apart, impinging on a flat surface located 5 mm above. Each impinging jets was positioned at the centre of the TEG cooling area. An experimental facility was constructed in order to test the minichannels heat exchanger and the impinging jets thermally and hydrodynamically. The heat transfer, pressure drop and temperature distribution results were compared to determine the most appropriate cold side heat exchanger prototype for the TEG POWER system. The TEG POWER system is a waste heat recovery system designed to recoup waste heat from the exhaust gases of commercial pizza ovens. The TEG POWER system is capable of harvesting waste thermal energy produced by an establishment and utilize it for electrical power generation and thermal storage purposes. Heat transfer results indicated that for a given mass flow rate the minichannels heat exchanger has better heat transfer performance compared to the impinging jets heat exchanger. The minichannels heat exchanger design had a thermal conductance of 238 W/C at 0.19 kg/s coolant flow rate compared to 111 W/C for the impinging jets heat exchanger. The total pressure drop and the minor losses for each heat exchanger prototype were measured experimentally. For the minichannels heat exchanger, the total pressure drop is 23.3 kPa at flow rate of 0.235 kg/s. Comparatively, the total pressure drop for the impinging jets heat exchanger was 27.4 kPa at the same flow rate. Fittings losses for the minichannels heat and impinging jets heat exchanger were found to be 50% and 80% respectively. The maximum total measured drop corresponded to pumping power requirements of 5.7 W and 6.8 W for the minichannels and impinging jets heat exchanger respectively. Local and average temperature distributions and their influence on the electrical power generated were studied for both heat exchanger prototypes. It was found that the minichannels heat exchanger offers more uniform surface temperature distribution per row of TEGs compared to the impinging jets heat exchanger. Therefore the minichannels heat exchanger is well suited for cooling two rows of TEGs simultaneously. Based on the thermal and hydrodynamics comparison results the minichannels heat exchanger prototype is recommended for implementation in the TEG POWER system. / Thesis / Master of Applied Science (MASc)

Laminar flat flame combustion has been studied with molecular-beam mass-spectrometry (MBMS) for a fuel-rich cyclohexane (Ф = 2.003) flame, a fuel-lean toluene (Ф = 0.895), and a fuel-rich toluene (Ф = 1.497) flame. Different hydrocarbon species in these flames were identified, and their mole fraction profiles were measured. The information can be used to propose reaction mechanisms for the different hydrocarbon flames. One MBMS apparatus located at Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory was used to identify and measure the mole-fraction profiles of different species in these flames. The MBMS apparatus located at University of Massachusetts Amherst was used to measure the temperature profile of the cyclohexane flame. The temperature profile of two different fuel-rich toluene flames (Ф= 2.02 , Ф = 3.94) and a fuel-lean (Ф=0.452) methane flame were also measured with the UMass apparatus.

In this bachelor’s thesis an introduction to the fundamentals of algebraic geometry is given. Some concepts in algebraic geometry are introduced such as Spec of a ring and Proj of a graded ring and several results related to these are either proven or stated. Special focus is directed towards defining the so called ”Hilbert scheme” which is the main topic in a lot of modern algebraic geometry research.

Flat affect (i.e., diminished expressivity) and self-reported anhedonia (i.e., lack of pleasure) are associated with many psychiatric disorders. There is a need to examine the relationship between specific anhedonia subtypes and flat affect in a non-clinical sample. Forty-seven undergraduate students (59% male; mean age 20.37; SD = 4.74) completed self-report questionnaires assessing four subtypes of anhedonia - consummatory/anticipatory by social/non-social. Participants then viewed 15 randomly-presented pictures (five neutral, ten negative) from the International Affective Pictures System while facial muscle activity (electromyography; EMG) was recorded. Male participants reporting a greater level of anhedonia, particularly consummatory social anhedonia, showed greater EMG activity change in the corrugator supercilii muscle to negative pictures, as compared with neutral pictures. Females showed the opposite pattern: more consummatory social anhedonia related to less EMG activity change in the corrugator muscle. In summary, consummatory social anhedonia in particular showed a strong relationship with facial expressivity that interacted with sex. In the presence of more consummatory social anhedonia, males show more negative facial reactions to negative stimuli while females show a more flattened affect. These findings may help explain discrepancies in existing research examining anhedonia and flat affect in clinical populations and have implications for etiology and treatments.

Thin filament pyrometry is a proven technique used to measure flame temperature by capturing the spectral radiance produced by the immersion of silicon carbide filaments in a hot gas environment. In this study a commercially available CMOS color camera was used, and the spectral response of each color channel was integrated with respect to the assumed graybody radiation spectrum to form a look up table between color ratio and temperature. Interpolated filament temperatures are then corrected for radiation losses via an energy balance to determine the flame temperature. Verification of the technique was performed on the Holthuis and Associates Flat Flame Burner, formerly known as the Mckenna Burner, and the results are directly compared to literature values measured on a similar burner. The results are also supported by radiation corrected measurements taken using a type B thermocouple on the same burner setup. An error propagation analysis was performed to determine which factors contribute the most to the final measurement uncertainty and confidence intervals are calculated for the results. Uncertainty values for a single point measurement were determined to be between ±15 and ±50 K depending on the color ratio and the total uncertainty associated with day-to-day changes in the measurement setup was found to be ±55 K. / Master of Science / Determination of flame temperature is an important aspect of combustion research and is often critical to the evaluation of combustion systems as well as the integration of those systems into more complex devices. In this thesis the technique of thin filament pyrometry was implemented and verified through the use of a well characterized calibration flame. This technique involves placing thin filaments usually made from silicon carbide into the flame and capturing the spectrum of light they emit with a detector. Since the amount of light emitted as well as which wavelengths the light is concentrated in is a strong function of temperature, this methodology may be used to calculate the temperature of the flame. Thin filament pyrometry has the advantage compared to other techniques in that it is extremely cheap to implement and requires no advanced scientific equipment. The SiC filaments have been shown to have a very high resistance to the flame environment and do not face many of the same challenges that can cause problems for other techniques. A statistical analysis of the method implemented in this work was also performed and the expected uncertainty was similar to many of the alternative techniques which necessitate a more complex or expensive setup.

Wind energy is identified a promising energy resource in Sri Lanka. Therefore, it is important to use proper technologies for efficient energy capturing in order to minimize cost of energy. Small scale wind turbines are usually installed in constricted places (particularly in urban areas) where wind flow is turbulent and difficult to predict. Savonious type vertical axis wind turbines are important due to several reasons such as good response to turbulent winds, high initial torque, low cost, low noise, less maintenance.In this study, a modified flat plate type Savonius wind rotor was proposed to cost effectively harness wind energy in constricted places. Generally, vertical axis wind turbines (VAWT) are less efficient than horizontal axis wind turbines, one reason behind this issue is wind force difference between the 2 sides of the axis is small and due to this reason torque is small and power generation capacity is less.A prototype of the proposed VAWT was fabricated and the performance was determined by acquiring experimental data. Artificial wind blow which was generated by a huge fan was used to measure rotational speed and torque characteristics at varying wind speeds. Data were collected with 1-second sampling time and a data acquisition system was developed under this study. In the proposed design one side of the turbine blades are facing the wind direction in order to capture maximum force while other side is edging the blades to have minimum opposite torque. With this concept it is expected to maximize the torque of the axis and generate more power. A sort of a passive pitch mechanism is therefore utilized in order to save energy and simplify the system. Turbine blades are simple flat plates and it eliminates usage of complex aero foils. Due to the simplicity of this design it would be possible to use this turbine for domestic electricity generation at affordable costs.Nowadays, net metering systems are being promoted in Sri Lanka and it would be beneficial to introduce low cost VAWT which operates at low winds as well as turbulent wind conditions. Based on typical household hourly load profile, viability of proposed vertical axis wind turbine was evaluated by considering rural and urban wind regimes in Sri Lanka. The costs of wind energy at two selected locations were determined in the context of net metering.

Manufacturing methods for aerospace composite parts are various. Vacuum assisted resin transfer moulding (VARTM) is one of the common methods. It requires manual draping of fabrics to produce preforms. The cost and quality of this method depend on the draping strategy, which is the sequence of draping operations performed by staff as they lay fabrics on moulds. These sequences can be very numerous with many possible starting points, yarn orientations, and fabrics used. In this group project, a predictive software tool is designed ultimately to identify the best draping strategy to reduce cost and improve quality in producing preforms. Generation of preform flat patterns for the CNC cutting tables, and of plybooks for providing instructions to shop floor staff, are developed and integrated into the predictive tool so that the manual draping process can potentially be conducted under the best draping strategy. The work presented in this thesis details the solutions for finding flat patterns for the best draping strategy for the CNC cutting tables, and the generation of plybooks for providing instructions to shop floor staff. The work is organized into four main parts: developing flattening algorithms for three types of base surfaces (BaS) defined in this project, developing a subsequent stitching algorithm aimed at stitching individual flattened BaS into a unified flat pattern for a given mould, lab validations to assess the proposed flattening and stitching algorithms, and establishing the capability to generate instruction .DXF files and plybooks for any received draping strategy. These algorithms are integrated into the predictive tool to facilitate manual draping processes under the optimal draping strategy.

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