Mass transfer experiments were conducted to study the thermal performance characteristics of blockages with round and elongated holes, positioned in a 12:1 rectangular channel. Naphthalene sublimation technique was adopted to conduct experiments with four different blockage configurations, flow rates corresponding to Reynolds numbers (based on channel hydraulic diameter) of 7,000 and 17,000, and at three blockage locations. The hole area to channel area ratio for all four blockage configurations was the same at 0.196. The hole width was half the channel height, and the distance between consecutive blockages was twice the channel height. Average heat transfer, local heat (mass) transfer and overall pressure drop results were obtained. The thermal performance for a particular blockage configuration was measured in terms of the heat transfer enhancement and the friction factor ratio. Heat transfer enhancement was measured as a ratio of average Nusselt number on the blockage surface to the Nusselt number for a thermally fully developed turbulent flow in a smooth channel. Results indicate that this ratio ranged between 3.6 and 12.4, while the friction factor ratio varied between 500-1700. The blockage configuration with round holes was found to yield best thermal performance, while the configuration with largest hole elongation was nearly equal in thermal performance. In order to compare different blockage configurations, an average value of upstream and downstream side thermal performances was used. A general downward trend in Nusselt number ratio with elongation of holes was observed on the upstream side and a reverse trend was observed on the downstream side. An upward trend in the Nusselt number ratio with blockage hole elongation on the downstream side of a blockage was primarily due to jet reversal from the downstream blockage and its impingement on the downstream surface of the upstream blockage. Local experiments were performed to compare against the results from average experiments and also to gain insights into the flow behaviour. There was good agreement between the results from local and average mass transfer experiments. The average variation in Nusselt number ratio between local and average mass transfer experiments was about 5.06%.

Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (leaves 85-93).

Simulation, optimization, and implementation of a capacitor-loaded wireless power transfer structure at 6.78 MHz for a target transfer distance of one meter are presented. First, an investigation into the operating principles behind a capacitor-loaded coupled loop structure is carried out via simulation. By adjusting the structural design parameters, it is found that an optimal configuration for this structure is coplanar. A prototype constructed using thin 18 AWG wire for the loops and a variable capacitor for tuning is used to verify simulation. To reduce losses in the wire, thick 9 AWG wire is implemented and measured. Thick wire is necessary for high efficiency yet undesirable for planarization. Since current flows only on the surface of the wire, ‘unwrapping’ that portion yields copper strips that reduce loss by increasing only the width. Thus, by replacing thick wires with copper strips, a planarized structure can be obtained that can reduce ohmic losses without sacrificing its form factor. Next, additional advantages of a capacitor-loaded system, which include reduced electric near-field and the possibility of resonant frequency tuning, are investigated. It is shown by simulation that the capacitor-loaded structure is not strongly affected by nearby dielectric materials since the stored electric energy is significantly lower than the stored magnetic energy in air at resonance. Finally, further optimizations of the structure are considered along with the analytical expressions for maximum efficiency. / text

Buildings are responsible for over a third of the energy consumption in the United States annually. This energy consumption contributes to some of the most pressing problems facing our society. Modeling of buildings and their systems is an integral part of most strategies for reduction of energy use in buildings. Modeling allows for informed building designs, optimization of systems, and greater market acceptance of new energy-saving technologies. This work addresses two particular modeling applications concerned with reduction of energy usage in buildings: convective heat transfer modeling in perimeter zones, and liquid desiccant dehumidification modeling. The first objective of this work is concerned with modeling convective transport in buildings and creation of inputs for energy modeling programs and passive pollutant removal calculations. This is accomplished through four investigations. In the first investigation, the influence of floor diffusers on convection heat transfer at perimeter zone windows in commercial buildings is measured. In the second, the impact of blinds on convection under a variety of circumstances is quantified. In the third, movement of air jets issuing from floor diffusers is predicted, and the effect of buoyancy on convective heat transfer at perimeter zone surfaces is analyzed. In the fourth investigation, convective mass transfer at indoor surfaces is investigated. Full scale experiments were conducted in support of these four investigations and semi-empirical correlations vii consistent with theory are given to predict jet movement and convective transport under a variety of circumstances. The second objective of this dissertation is concerned with modeling and analysis of liquid desiccant dehumidification systems and is pursued through three additional investigations. The first is concerned with modeling small-scale transport within the channels of a liquid desiccant absorber and regenerator. Physical and empirical models are developed which agree well with laboratory data. During the second investigation, a dynamic model of a liquid desiccant dehumidification system is developed and integrated into a full-building energy simulation. This is used to assess the potential applicability of the system in supermarkets in various climates. The models developed are used to optimize the system and develop a procedure to size components in the final investigation. / text

The iOS 7 Core Bluetooth Framework (CB) is finally at a level where it can be used in projects to create valuable iOS applications. Due to its maximum broadcast radius of 30ft it lends itself to nearby communication. This thesis explores the Bluetooth space generally before delving into location-based data transfer using Bluetooth. The CB provided by Apple is powerful, but somewhat cumbersome. It forces the developer to deal with details related to device discovery and connections which can be tangential to the goal of the developer: sending data between devices. I built the Lightweight Bluetooth Framework (LBF) which makes the features of the CB more accessible by abstracting away from the implementation details of CB. LBF supports any number of data types being transferred as well as any number of total pieces of data regardless of data type. The system accomplishes this by assigning specific Characteristics to a particular data type and having pieces of data be uniquely identified with an ID when they are broadcasted. This unique ID is then used to associated the proper object with the received data. This will enable developers to focus on the implementation of their App without getting hung up on the details of the CB. Additionally, benchmark tests are done on the Lightweight Bluetooth Framework to determine what data transfer speed the framework supports. These tests reveal that transfer speed depends on hardware, but independent of hardware are too slow to transfer images, video, or sound.

A mechanism for the mass transfer of anthraquinone (AQ) into wood during alkaline pulping has been developed. Although the chemistry of action of AQ is well-developed, there has not been much work conducted on its diffusion properties. The discrepancies between different experiments with AQ indicate that something other than the chemistry is at work. Because most of the differences arise from differences in pulping conditions, it is likely that mass transfer is the source of these discrepancies. A model system was therefore developed to explore the mass transfer properties of AQ. It was shown that AQ must be reduced to anthrahydroquinone (AHQ) at the membrane surface before any permeation of a membrane can occur. It was also shown that increasing surface coverage of the membrane through AQ particle size reduction could improve the rate of membrane permeation. The mechanism described by the model system was then tested against pulping data. It was shown that the addition of surfactants increases the pulping efficiency of AQ. This is probably through better dispersion of AQ particles to cover more chip surface area. Bulk reduction effects were also tested, and it was shown that bulk phase reducing agents decrease the efficacy of AQ in pulping. This led to the development of the mechanism for AQ diffusion in alkaline pulping.

Thesis (doctoral)--Universität Erlangen.

Revision of Thesis (Ph. D.)--George Washington University, 1979. / Includes bibliographical references (p. [159]-165) and index.

Thesis (Ph.D.)--University of Delaware, 2009. / Principal faculty advisor: Fabrice Veron, College of Earth, Ocean, & Environment. Includes bibliographical references.

Thesis (Ph. D.)--University of California, Berkeley, 1991. / Includes bibliographical references (leaves 364-378).