No description available.

<p>The production of a novel micropump based on the synthetic jet principle is investigated both numerically and experimentally. The proposed micropump consists of a synthetic jet actuator driven by a vibrating diaphragm issuing into an inverted T- shaped channel structure forming the inlet/outlet channels of the pump.</p> <p>The software package Ansys is used to perform numerical investigations of the operation of the proposed micropump. Simulations were performed to study the effect of changing the inlet/outlet channel dimensions as well as the operating frequency, amplitude and duty cycle of the excitation signal. Inlet/outlet channel widths ranging from 200 to 800 μm and operating amplitude and frequency of excitation of the 5 mm square membrane driving the synthetic jet actuator ranging from 20 to 60 μm and from 20 to 60 Hz respectively were investigated.</p> <p>Based on the findings of the numerical simulations, a prototype design was chosen and produced. Prototype production using microfabrication techniques as well as micromachining was investigated. The final prototype was micromachined using plexiglass as the working material. An experimental setup was constructed to test the performance of the produced prototype, which allowed for measuring the produced flow rate, pressure head, actuation amplitude and frequency.</p> <p>The findings of the numerical simulations verified the possibility to produce a working micropump with flow rates of up to 1.3 ml/min. Simulation results also showed the dependence of the produced flow rate on both the inlet and outlet channel widths. An increase in the inlet channel width resulted in a gain in the average flow rate through the pump while an increase in the outlet channel width results in a reduction in the flow rate. Increases in either the actuation amplitude or frequency of excitation both resulted in an improvement in the produced flow rate. Changes in the ejection duty cycle, or the ejection time relative to the suction time during an actuation cycle, were found to influence the flow rate produced by the pump. A shorter ejection time produced a higher flow rate from the pump as compared to a longer ejection time. It was also found that changes in dimensions or operating parameters affected the fluctuations in the flow rate through the pump associated with the pulsating nature of the synthetic jet. Experimental investigations confirmed the findings of the numerical simulations in terms of the flow rate and the trends in the dependence of the flow rate on operating parameters. Values of maximum back pressure of up to 500 Pa were also reported experimentally and membrane driving powers of up to 122 μW were calculated numerically.</p> / Doctor of Philosophy (PhD)

The advent of synthetic transcriptional regulators built mainly on human-derived proteins, namely synthetic Zinc Finger Transcription Regulators (synZiFTRs), has enabled fine-tuned control of therapeutically significant genes in primary T cells. However, their clinical relevance could be enhanced by amplifying synthetic gene circuit activation and expanding the synZiFTR toolkit with standardized compo-nents for the construction of more complex circuits. This study describes the de-velopment of the next iteration of synZiFTR, the synZiFTR2.0, incorporating the human-derived transcription elongation domain, IWS1. We present an engi-neered version 2.0 of GZV- and 4OHT/TMX-regulated gene switches, exhibiting a robust increase in transcriptional output upon drug induction. Furthermore, the synZiFTR toolkit was expanded and utilized to examine the feasibility of con-structing a two-input AND logic gate. Interestingly, the integration of IWS1 un-veiled a potential role of PP1-NUTS phosphatase in enhancing synthetic circuit output, though the precise mechanism warrants further investigation. The intro-duction of synZiFTR2.0 is projected to boost its clinical applicability, particularly in settings where circuit output strength is contingent on disease context that is often uncertain. / 2025-10-03T00:00:00Z

Made available in DSpace on 2014-06-11T19:25:29Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-10-30Bitstream added on 2014-06-13T18:28:51Z : No. of bitstreams: 1 junqueira_lhp_me_mar_prot.pdf: 265340 bytes, checksum: daf69a1d10690f402ce7b118240d49da (MD5) / É antiga a preocupação do ser humano com as questões relacionadas ao conhecimento, incluindo as discussões sobre a sua origem, seu aprendizado, sobre a nossa capacidade de utiliza-lo e sobre as características específicas da cognição humana. Essa preocupação remonta aos antigos filósofos gregos (2.500 A.C.), desenvolvendo-se posteriormente a partir da abordagem da Epistemologia, originária da Filosofia ocidental, e mais recentemente a partir do Funcionalismo, pertencente aos estudos em Filosofia da Mente e em Ciência Cognitiva. Essa última abordagem, em particular, contribuiu para o surgimento de programas de pesquisas que procuram entender o funcionamento da mente humana com a ajuda do computador. A Ciência Cognitiva possui fortes ligações com as pesquisas em Inteligência Artificial, e ambas vem se desenvolvendo desde a década de 1950. Mais recentemente, a partir da década de 1980, uma nova área de estudos surgiu, formada por pesquisas em Vida Artificial, que trabalha com a possibilidade de síntese de entidades vivas, por meios artificiais, e desde então vem chamando a atenção de pesquisadores interessados no estudo da cognição. Enquanto a Ciência Cognitiva tem ligações estreitas com a Filosofia e a Psicologia, a Vida Artificial tem uma forte inspiração na Biologia. Neste trabalho, procuramos investigar o encontro entre essas disciplinas, e seus programas de pesquisas, considerando as possibilidades de contribuição para o estudo da cognição humana, a partir de uma abordagem conjunta entre essas áreas. / It is na old thing the human concern about knowledge related questions, including discussions on its origin, its learning, about our capacity to utilize it and about specific characteristics of the human cognition. That concern remounts to the ancient greek philosophers (2.500 B.C.), developing itself later from the approach of Epistemology, originated in the occidental Philosophy, and more recently from the Functionalism, that makes part of the studies of Philosophy of Mind and of Cognitive Science. This last approach, particularly, contributed to appearing of research programs that try to understand the function of the human mind with the help of the computer. The Cognitive Science has strong relation with research in Artificial Intelligence, and both areas have been growing since the 1950 decade. More recently, from the decade 1980 on, a new area of atudies appeared, formed by researches in Artificial Life, that work with the possibility of synthesis of alive entities, by artificial means, and sice then has been attracting the attention of researchers interested in the study of Cognition. While Cognitive Science has strict relations with the Philosophy and the Psychology, Artifiical life has a strong inspiration in the Biology. In this work, we tried to investigate the meeting between these subjects, and their research programs, considering the possibilities of the contribution to the study of the human cognition, by means of an integrated approach of these areas.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

Call number: LD2668 .T4 1978 N57 / Master of Science

This thesis provides a new explanation for the behaviour of radar backscatter of forests using vegetation structure models from the field of macroecology. The forests modelled in this work are produced using allometry-based ecological models with backscatter derived from the parameterisation of a radiative transfer model. This work is produced as a series of papers, each portraying the importance of macroecology in defining the forest radar response. Each contribution does so by incorporating structural and dynamic effects of forest growth using one of two allometric models to expose variations in backscatter as a response to vertical and horizontal forest profiles. The major findings of these studies concern the origin of backscatter saturation effects from forest SAR surveys. In each work the importance of transition from Rayleigh to Optical scattering, combined with the scaling effects of forest structure, is emphasised. These findings are administered through evidence including the transition’s emergence as the region of dominant backscatter in a vertical profile (according to a dominant canopy scattering layer), also through the existence of a two trend backscatter relationship with volume in the shape of the typical “saturation curve” (in the absence of additional attenuating factors). The importance of scattering regime change is also demonstrated through the relationships with volume, basal area and thinning. This work’s findings are reinforced by the examination of the relationships between forest height and volume, as collective values, providing evidence to suggest the non-uniqueness of volume-toheight relationships. Each of the studies refer to growing forest communities not single trees, so that unlike typical studies of radar remote sensing of forests the impact of the macroecological structural aspects are more explicit. This study emphasises the importance of the overall forest structure in producing SAR backscatter and how backscatter is not solely influenced by electrical properties of scatteres or the singular aspects of a tree but also by the collective forest parameters defining a dynamically changing forest.

The development of sustainable replacements for fossil fuels has been spurred by concerns over global warming effects. Biofuels are typically produced through fermentation of edible crops, or forest or agricultural residues requiring cost-intensive pretreatment. An alternative is to use photosynthetic cyanobacteria to directly convert CO2 and sunlight into fuel. In this thesis, the cyanobacterium Synechocystis sp. PCC 6803 was genetically engineered to produce the biofuel n­-butanol. Several metabolic engineering strategies were explored with the aim to increase butanol titers and tolerance. In papers I-II, different driving forces for n-butanol production were evaluated. Expression of a phosphoketolase increased acetyl-CoA levels and subsequently butanol titers. Attempts to increase the NADH pool further improved titers to 100 mg/L in four days. In paper III, enzymes were co-localized onto a scaffold to aid intermediate channeling. The scaffold was tested on a farnesene and polyhydroxybutyrate (PHB) pathway in yeast and in E. coli, respectively, and could be extended to cyanobacteria. Enzyme co-localization increased farnesene titers by 120%. Additionally, fusion of scaffold-recognizing proteins to the enzymes improved farnesene and PHB production by 20% and 300%, respectively, even in the absence of scaffold. In paper IV, the gene repression technology CRISPRi was implemented in Synechocystis to enable parallel repression of multiple genes. CRISPRi allowed 50-95% repression of four genes simultaneously. The method will be valuable for repression of competing pathways to butanol synthesis. Butanol becomes toxic at high concentrations, impeding growth and thus limiting titers. In papers V-VI, butanol tolerance was increased by overexpressing a heat shock protein or a stress-related sigma factor. Taken together, this thesis demonstrates several strategies to improve butanol production from cyanobacteria. The strategies could ultimately be combined to increase titers further.

International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California / To help students learn the principles of microwave engineering and electromagnetic theory, labs were developed in which the students built a rail-synthetic aperture radar(SAR) and a Doppler radar. These labs gave the students practical experience in the paper design, simulation, construction, testing, and debugging of RF circuits. This paper includes a description of the design, physical construction, the basic operation, and the results from these projects.

International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / In this paper, the research prototype of a high-performance GPR imaging system is presented. The system is equipped with the capability of synthetic-aperture scan, stepfrequency FMCW illumination, and high-resolution tomographic image reconstruction.