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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.
101

Cardiac Looping und die frühe Topogenese der AV-Region: Untersuchung an Hühnerembryonen / Cardiac looping and the early topogenesis of the atrioventricular canal (avc) in the embryonic chick heart

Reichel, Thomas 22 August 2017 (has links)
No description available.
102

Construction, manipulation et visualisation de processus sonores dans des environnements virtuels immersifs pour la performance musicale

Berthaut, Florent 07 October 2010 (has links)
Le travail présenté dans cette thèse s’inscrit à la fois dans le domaine de l’informatique musicale et dans celui de la réalité virtuelle. Nous présentons tout d’abord les avantages des environnements virtuels immersifs et de l’interaction graphique 3D pour les instruments multi-processus et en particulier pour le live-looping hiérarchique, un nouveau modèle d’instrument que nous définissons. Nous proposons ensuite des solutions pour la visualisation et la manipulation des processus sonores dans ces environnements virtuels. Afin de représenter les processus sonores, nous introduisons les widgets réactifs 3D qui s’appuient sur des mappings audiovisuels que nous évaluons. Nous développons un nouveau dispositif d’interaction 3D adapté à l’interaction musicale, appelé Piivert, ainsi que des techniques associées, dont les tunnels, afin de manipuler les widgets réactifs 3D. Finalement, nous mettons en œuvre le live-looping hiérarchique avec l’instrument immersif Drile, en utilisant les techniques développées précédemment, et nous étudions plusieurs scènes pour les performances musicales immersives. / The work presented in this thesis belongs to the computer music field as well as to the virtual reality field. First, we describe the advantages of immersive virtual environments and of 3D graphical interaction for multiprocesses instruments and particularly for the hierarchical live-looping, a new instrument model that we define. We then suggest solutions to visualize and manipulate sound processes in these virtual environments. In order to display the sound processes, we introduce the 3D reactive widgets, which rely on audiovisual mappings that we study. We develop a novel 3D interaction device suitable for musical interaction, called Piivert, together with associated interaction techniques, among which the tunnels, in order to manipulate the 3D reactive widgets Finally, we implement the hierarchical live-looping with an immersive instrument called Drile, using the previously developped techniques, and we study different stages for immersive musical performances.
103

Steam Enhanced Calcination for CO2 Capture with CaO

Champagne, Scott January 2014 (has links)
Carbon capture and storage technologies are necessary to start lowering greenhouse gas emissions while continuing to utilize existing thermal power generation infrastructure. Calcium looping is a promising technology based on cyclic calcination/carbonation reactions which utilizes limestone as a sorbent. Steam is present in combustion flue gas and in the calciner used for sorbent regeneration. The effect of steam during calcination on sorbent performance has not been extensively studied in the literature. Here, experiments were conducted using a thermogravimetric analyzer (TGA) and subsequently a dual-fluidized bed pilot plant to determine the effect of steam injection during calcination on sorbent reactivity during carbonation. In a TGA, various levels of steam (0-40% vol.) were injected during sorbent regeneration throughout 15 calcination/carbonation cycles. All concentrations of steam were found to increase sorbent reactivity during carbonation. A level of 15% steam during calcination had the largest impact. Steam changes the morphology of the sorbent during calcination, likely by shifting the pore volume to larger pores, resulting in a structure which has an increased carrying capacity. This effect was then examined at the pilot scale to determine if the phase contacting patterns and solids heat-up rates in a fluidized bed were factors. Three levels of steam (0%, 15%, 65%) were injected during sorbent regeneration throughout 5 hours of steady state operation. Again, all levels of steam were found to increase sorbent reactivity and reduce the required sorbent make-up rate with the best performance seen at 65% steam.
104

Energy and Exergy Analysis of Chemical Looping Systems for Hydrogen and Sulfur Recovery

Reddy, Sharath 30 September 2019 (has links)
No description available.
105

Envisioning Catalytic Processes in Chemical Looping Systems: Material and Process Development

Baser, Deven Swapneshu 05 October 2020 (has links)
No description available.
106

Chemical Looping Partial Oxidation for the Conversion of Natural Gas and Biomass to Syngas: Experimental Aspects, Process Integration, and Electric Capacitance Volume Tomography

Park, Cody 12 September 2022 (has links)
No description available.
107

The Effects of Looping on the Academic Achievement of Elementary School Students.

Bogart, Vada S. 14 December 2002 (has links) (PDF)
The purpose of this study was to compare the academic achievement of students in looping programs from school systems in East Tennessee to their peers in traditional one-year instructional programs. Looping is defined as any program design that perpetuates a cohesive student group with the same teacher for more than one year. The study included all students who had completed fourth grade in 2001 at every school in East Tennessee that implemented a third/fourth grade looping design. Student scores reported for 1999, 2000, and 2001 on the TerraNova Standardized Achievement Test were obtained from individual student records. Comparisons were made on the Total Reading, Total Language, Total Math, and Total Battery scores. Differences between program design groups (looping and traditional) on "pre-looping" second grade (1999) scores were assessed using t-tests for two independent groups. Two-way Analysis of Covariance (ANCOVA), was used to examine the main effects of program design and student gender on 2000 and 2001 test scores, along with program design x gender interactions, while controlling for prior test score differences. The findings suggested that students in looping classrooms benefited academically by remaining with the same teacher and classmates for two successive years. Significant main effects were detected for program design in first year comparisons, as indicated by significantly higher scores on all four subtests. Scores for those in the looping classrooms remained significantly higher in second year comparisons on each subtest, except Total Language, even after controlling for third grade (2000) test scores. Significant main effects for gender were detected after the first year of participation in each design. This included significantly higher Total Language and Total Battery scores for female participants. No significant differences by gender were detected when scores were compared on the four subtests at the end of the two-year cycle. A program design x gender interaction was detected at the end of the first year. This interaction showed that female participants in looping classrooms showed higher Total Math achievement. A program design x gender interaction also occurred after the second year where male participants in the looping classrooms obtained higher Total Language scores.
108

Exploring Strategies for Syngas Generation using Calcium-Iron based Oxygen Carriers in Chemical Looping Systems

Shah, Vedant R. January 2021 (has links)
No description available.
109

Calcium Oxide based Carbon Capture in District Energy Systems / Kalciumoxidbaserad koldioxidavskiljning i distriktets energisystem

Vora, Mit Jayesh January 2022 (has links)
Global carbon emissions are higher than ever before and in the last decade of 21st century, focus has shifted on reducing these emissions in various ways possible. Carbon capture, utilization and storage (CCUS) has been identified as one of the important ways to reduce carbon emissions and meet climate targets. For a long time, Sweden has promoted the use of biomass as fuel for heat and power generation which has enabled it to meet its climate targets earlier than projected. Now, major Swedish energy companies are looking into coupling exiting biomass fired heat and power plants with CCUS. This opens up the possibility of attaining negative emissions, also known as Bio Energy Carbon Capture and Storage (BECCS). With the right policy framework in place, BECCS can be a major boon and help Sweden attaining net zero carbon emissions. As a contribution in meeting net zero targets, this thesis is aimed to evaluate the installation of a carbon capture plant to abate flue gas emissions from District heating facility in Jordbro which is a ~70 MW (fuel) CHP plant running on biomass.  Among the available carbon capture technologies, Calcium oxide-based carbon capture has been expected to show great promise due to its lower environmental impacts and possibility to extract high quality energy when installed. Hence a concept system for integration calcium looping at Jordbro has been developed through the use of modeling tools like ASPEN. A techno economic assessment was needed to be performed to give conclusive results on the overall viability of the process. Further, key process indicators like energy penalty, plant footprint and cost of capture per tonne of CO2 were identified for making the final evaluation. Finally, through a strategic collaboration with SaltX, major process improvements were introduced and applied to the modeled process.  It was concluded that with the current average flowrates at Jordbro it was possible to capture 154,000 tonnes of CO2 annually. The required amount of energy input to the calciner is 48MW (7.29 MW/kg-CO2 captured) which is one of the major findings of this study. Even though a significant amount of heat is recovered, the main boiler is not capable of producing heat over 900 οC and additional biomass needs to be combusted, leading to an additional CO2 emission of about 125 000 tonnes annually. Considering an optimal integration, the energy penalties became 6.25 %.  However, the plant footprint increased substantially due to requirement for burning additional biomass in the regeneration reactor and addition of several auxiliary units that come along with calcium-based carbon capture. Further, the total capital investment for this project is 1,219 MSEK with reactor costs being most capital intensive. Assuming a plant life of 25 years, the cost of capture per tonne of CO2 (excluding the costs for carbon transport and storage) was evaluated at 988 SEK, which is 58% higher than the reference Mono-ethanol amine based chemical absorption case. The innovative improvements from SaltX substantially reduced the plant footprint but capture costs did not reduce since material transport costs proved to be the major bottleneck.  Upon comparison of this technology with the amine-based technology it was found that Calcium oxide-based carbon capture would need further research and improvements to be more viable than amine-based carbon capture. Integration of thermal energy storage and process intensification can be the possible paths for further improvement.
110

Continuous Processing of Agricultural and Plastic Wastes via Chemical Looping and the Integration of Advanced System Design for the Production of Direct Reduced Iron

Falascino, Eric Joseph January 2022 (has links)
No description available.

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