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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Pokročilé oxidační procesy v environmentálních aplikacích / Advanced oxidation processes in environmental applications

OLŠAN, Pavel January 2013 (has links)
The aim of this thesis is the study of application of the synergistic effects of various advanced oxidation processes (AOP) used for decomposition of chemical compounds resistant to biodegradation. The synergistic effect of photocatalytically active material and low temperature plasma were tested in my thesis. Model substances with photocatalytically active material were exposed to atmospheric plasma discharge (Gliding Arc) in order to improve generation of the active hydroxyl groups and oxidation processes. The first chapter of the theoretical part summarizes the knowledge of advanced oxidation processes, their principles and utilization. Next chapters are dedicated to basic summary of titanium dioxide and types of creating the thin films. The last part of theoretical chapter describes the types of plasma discharges. The experimental part describes the equipment for decomposition of chemical compounds resistant to biodegradation using AOP. Next chapter of the experimental part is dedicated to decomposition of organic dye AO7 and antibiotic Verapamil hydrochloride. The last chapter summarizes the results of the experiments.
22

Etude des procédés plasmas dans l'élimination des polluants organiques persistants dans les effluents aqueux / Study of process plasmas in elimination of the persistent organic polutants in the aqueous effluents

Koyaouili, Thierry-Jocker 12 December 2016 (has links)
Ces travaux de recherche ont permis de comparer la performance de réacteur glidarc première et deuxième génération pour le traitement de l'eau polluée. Le réacteur DBD pointe/plan a été également développe. L'étude de caractérisation de transfert de matière dans les réacteurs glidarc ainsi que de l'efficacité énergétique ont montre que le reacteur glidarc de la première génération est plus performant que celui de la deuxième génération. La différence entre ces deux reacteurs est due par le temps de contact plasma solution et le phénomène transfert gaz-liquide. Notons cependant que la conversion du phénol est majoritairement réalisée avec les espèces nitrogènes. La modélisation numérique sous COMSOL a confirme le mécanisme de conversion du phénol propose. L'étude paramétrique d'élimination de l'acide acétique avec le réacteur DBD pointe/plan a montre que le générateur de haute fréquence (40 kHz) dégage énormément de chaleur qui contribue certainement au transfert de matière du polluant de la solution vers le gaz. il est donc envisageable d'apporter l'énergie petit a petit au système en utilisant le générateur de basse fréquence (500 Hz). / These research tasks made it possible to compare the performance of reactors gliding arcs first and second generation for the water treatment polluted. A reactor DBB point/plane was also developed. The study of characterization of transfer of matter in the rectors gliding arc as of the energy effectiveness showed that the engine gliding arc first generation is performent than that of the second generation. The difference between these two reactors must by the time of contact plasma solution and the phenomenon gas-liquid transfer. Let us note however that the conversion of phenol is mainly carried out with the species nitrogens. The numerical modeling under Comsol confirmed the mechanism of conversion of phenol proposed. The parametric study of elimination of the acetic acid with reactor DBD point/plane showed that the high frequency generator (40 kHz) releases enormously from heat which contributes certainly to the transfer of matter of the pollutant of the solution towards gas. It is thus possible to bring energy gradually to the system by using the low frequency generator (500 Hz) However, energy efficiency study has shown that low-frequency generator (500Hz) is more efficient than the high-frequency generator (40kHz). Which is justified by the fact that the energy consumed by the power of high-frequency generator is higher, making it uncompetitive.
23

Diversity, Distribution and Status of Gliding Squirrels in Protected and Non-protected Areas of the Eastern Himalayas in India

Krishna, Murali C., Kumar, Awadhesh, Tripathi, Om Prakash, Koprowski, John L. January 2016 (has links)
The tropical forests of South and Southeast Asia hold the highest gliding squirrel diversity but our knowledge of species diversity, ecology and major threats is limited. The present study was undertaken in Arunachal Pradesh, Northeast India between June 2011 and March 2015 to address the paucity of data available on gliding squirrels. Based on field and literature surveys, 14 species of gliding squirrels were detected in the state of Arunachal Pradesh. However, species such as Biswamoyopterus biswasi, which is reported as endemic to Namdapha National Park, were not detected. The high gliding squirrel diversity in this region could be related to a diversity of forest types and its location between the Himalayas and the Indomalayan region. Encounter rates with four different species revealed that Petaurista petaurista was most frequently detected in Namdapha National Park. Major threats include hunting for traditional medicine, cultural purposes or bushmeat, and habitat loss due to forest degradation caused by shifting cultivation. In addition, more intensive studies on population, ecology and conservation status are needed in order to design species and site specific conservation action plans in this region which represents the highest diversity of gliding squirrels globally.
24

MultiMo-Bat: Biologically Inspired Integrated Multi-Modal Locomotion

Woodward, Matthew A. 01 December 2017 (has links)
The combination or integration of locomotion modes, is analyzed through the design, development, and verification of a miniature integrated jumping and gliding robot, the MultiMo-Bat, which is inspired by the locomotion strategies of vampire bats, locusts, and pelicans. This robot has a mass of between 100 and 162 grams and exhibits high jumping and gliding performance, reaching heights of over 4.5 meters, to overcome obstacles in the environment. Integration results in a smaller, lighter robot with high cooperation between the modes. This thesis presents a previously unstudied robot design concept and highlights the understudied evolutionary concept within organism mobility of integration of locomotion modes. High performance locomotion modes also require high energy density actuators. To this end, a design methodology is developed for tailoring magnetic springs to the characteristics of shape memory alloy-actuated mechanisms, which allow the MultiMo-Bat to reach jumping heights of 3.5 m with active wing deployment and full controller. Through a combinations of permanent magnets, a magnetic spring can be customized to desired characteristics; theoretically any welldefined function of force vs. displacement can be created. The methodology is not limited to SMA but can be adapted to any smart actuator, joint, or situation which requires a fixed complex force-displacement relationship with extension other interactions and magnetic field design. Robotic locomotion is also much more idealized than that of their biological counter parts. This thesis serves to highlight just how non-ideal, yet robust, biological locomotion can inspire concepts for enhancing the robustness of robot locomotion. We studied the desert locust (Schistocerca gregaria), which is adapted for jumping at the extreme limits of its surface friction, as evident by its morphological adaptations for not only jumping, but slipping. Analysis of both foot morphology and jumping behavior are used to understand how the feet interact with different surfaces, including hydrophobic glass, hydrophilic glass, wood, sandstone, and mesh. The results demonstrate a complex interplay of embodied mechanical intelligence, allowing the foot to interact and adapt passively to different surfaces without burdening the organism with additional tasks. The key morphological and dynamical features are extracted to create a concept for developing multi-Surface Locust Inspired Passively-adaptable (SLIP) feet. A simple interpretation of the concepts are then used to construct a SLIP foot for the MultiMo-Bat. These feet allow the MultiMo-Bat to reach jumping heights of well over 4 m, greater than any other electrically powered robot, and this is achieved on a 45 degree angled surface while slipping. The SLIP foot concept can be directly applied to a wide range of robot size scales, thus enhancing their dynamic terrestrial locomotion on variable surfaces.
25

Evidence that a partner-switching regulatory system modulates hormogonium motility in the filamentous cyanobacterium Nostoc punctiforme

Riley, Kelsey Wynne 01 January 2018 (has links)
Partner-switching regulatory systems (PSRSs) are utilized by many different bacteria to regulate a wide array of cellular responses, from stress response to expression of virulence factors. The filamentous cyanobacterium Nostoc punctiforme can transiently differentiate motile filaments, called hormogonia, in response to various changes in the environment. Hormogonia utilize a Type IV pilus (T4P) complex in conjunction with a secreted polysaccharide for gliding motility along solid surfaces. This study identified three genes, designated hmpU, hmpW, and hmpV, encoding the protein components of a PSRS involved in regulation of hormogonium motility in N. punctiforme. Although mutant strains with in-frame deletions in hmpU, hmpW, and hmpV differentiated morphologically distinct hormogonium-like filaments, further phenotypic analysis demonstrated significant distinctions among the strains. The ∆hmpW strain contained a higher percentage of motile filaments that moved faster than the wild-type strain, while the ∆hmpU and ∆hmpV strains consisted of fewer motile filaments that moved at a slower rate compared to wild type. Immunoblotting and immunofluorescence of PilA, the major component of the pilus in the T4P system, showed that although all mutant strains appeared to express similar levels of PilA protein, the ∆hmpU and ∆hmpV strains displayed reduced extracellular PilA. Lectin blotting and staining with fluorescently-labeled UEA lectin demonstrated a decrease in extracellular hormogonium polysaccharide in the ∆hmpU and ∆hmpV strains, consistent with the current understanding that the polysaccharide is secreted via the T4P system. Epistasis analysis demonstrated that the ∆hmpW, ∆hmpV double-deletion mutant strain displayed reduced spreading in plate motility assays, similar to the ∆hmpV single mutant. Together, these results support a model in which the HmpU phosphatase and HmpW serine kinase control the phosphorylation state of the HmpV protein, modulating its activity on a downstream target to ultimately promote activation of the T4P motor complex and enhance hormogonium motility.
26

Structure and Function of the Electron-dense Core in Mycoplasma pneumoniae and its Relatives

Hatchel, Jennifer M. 22 July 2009 (has links)
No description available.
27

Gliding Motility Mechanisms in Divergent Mycoplasma Species

Relich, Ryan F. 23 September 2011 (has links)
No description available.
28

Structure, Organization, and Function of the Terminal Organelle in Mycoplasma penetrans

Jurkovic, Dominika Angelika 04 September 2012 (has links)
No description available.
29

A Self-Sustaining, Boundary-Layer-Adapted System for Terrain Exploration and Environmental Sampling

Morrow, Michael Thomas 18 August 2005 (has links)
This thesis describes the preliminary design of a system for remote terrain exploration and environmental sampling on worlds with dense atmospheres. The motivation for the system is to provide a platform for long-term scientific studies of these celestial bodies. The proposed system consists of three main components: a buoyancy-driven glider, designed to operate at low altitude; a tethered energy harvester, extracting wind energy at high altitudes; and a base station to recharge the gliders. This system is self-sustaining, extracting energy from the planetary boundary layer. A nine degree of freedom vehicle dynamic model has been developed for the buoyancydriven glider. This model was used to illustrate anecdotal evidence of the stability and controllability of the system. A representative system was simulated to examine the energy harvesting concept. / Master of Science
30

Flying snakes: Aerodynamics of body cross-sectional shape

Holden, Daniel Patrick 26 May 2011 (has links)
Chrysopelea paradisi, also known as the flying snake, possesses one of the most unique forms of aerial locomotion found in nature, using its entire body as a dynamic lifting surface without the use of wings or membranes. Unlike other airborne creatures, this species lacks appendages to aid in controlling its flight trajectory and producing lift. The snake exhibits exception gliding and maneuvering capabilities compared with other species of gliders despite this lack of appendages. While gliding, C. paradisi morphs its body by expanding its ribs, essentially doubling its width and utilizing its entire length as a reconfigurable wing. Its cross-sectional shape transforms into a thick, airfoil shape with a concave ventral surface, outwards protruding lips at the leading and trailing edges, a somewhat triangular dorsal surface with a round apex, and fore-aft symmetry. This study investigated the aerodynamic performance of this unique shape by simulating a single, static segment of the snake's body over a wide range of Reynolds numbers (3,000 to 15,000) and angles of attack (-10 to 60o) to simulate the full range of the snake's flight kinematics. This is the first study on an anatomically accurate snake model, and few aerodynamic studies have been performed in this low Reynolds number regime. Load cell measurements and time-resolved digital particle image velocimetry (TRDPIV) were performed on a 2D anatomically accurate model to determine the lift and drag coefficients, wake dynamics, and vortex shedding characteristics. This geometry produced a maximum lift coefficient of 1.9 and maximum lift to drag ratio of 2.7, and maintained increases in lift up to 35o. Overall, this geometry demonstrated robust aerodynamic behavior by maintain significant lift production and near maximum lift to drag ratios over a wide range of test parameters. These aerodynamic characteristics may enable the flying snake to glide at steep angles and over a wide range of angles of attack, often encountered in gliding trajectories. This geometry also produced larger maximum lift coefficients than many other bluff bodies and airfoils in this low Reynolds number regime. This thesis is organized as follows. The first section contains a broad introduction on gliding flight and C. paradisi's unique mode of gliding. The following section is a manuscript that will be submitted to a journal and contains the experimental analysis on the snake's cross-sectional shape. Several appendices attached to the end of this thesis contain additional analysis and work performed throughout the duration of this project and unique Matlab algorithms developed during this research. / Master of Science

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