• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 3686
  • 1177
  • 596
  • 520
  • 502
  • 247
  • 202
  • 202
  • 202
  • 202
  • 202
  • 193
  • 107
  • 74
  • 61
  • Tagged with
  • 9084
  • 1907
  • 1041
  • 903
  • 876
  • 808
  • 720
  • 513
  • 489
  • 457
  • 453
  • 452
  • 436
  • 425
  • 400
  • 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.
251

AQM Shell Development - Creating a Framework for Airspace and Airfield Operations and Air Quality Visualization Software

Peterson, Todd Alan 15 October 1997 (has links)
It is believed that the analysis of air traffic impacts on air quality will benefit from attention to the three-dimensional nature of the air traffic network as well as the actions of individual aircraft during the study period. With the existence of air traffic simulation models, the actions of individual aircraft may already be defined in a simulated environment. SIMMOD, the Federal Aviation Administration's airport and airspace modeling software, performs such models of scheduled air traffic. The results of such models may be used to determine the impacts of scheduled air traffic on air quality as well as other parameters. This report addresses the interpretation of output from SIMMOD models for use in air quality analysis and visualization of the air traffic network, and the application of these techniques in a stand-alone computer program. This program, named AQM for its purpose in assisting development of Air Quality Models, provides a working framework for future development of software for detailed air quality analysis and visualization. / Master of Science
252

Investigation of the Cause and Effect of Air Void Coalescence in Air-Entrianed Concrete Mixes

Camposagrado, Gabriel Rene 07 August 2004 (has links)
Air entraining admixtures (vinsol or non-vinsol) are used in concrete mixes that will be exposed to freeze-thaw cycles or sulfate attack. Entrained air is intended to improve the durability and resistance of hardened concrete to freeze-thaw cycles. However in many instances a significant loss of compressive strength has been observed in concrete mixes containing non-vinsol admixtures. Mixture forensic analysis has determined air void coalescing to be the main factor in observed low compressive strengths. The result of air void coalescing is the over design of compressive strength to account for the possible lower strengths and decreased confidence in the compressive strengths obtained during the quality control/assurance process.
253

Fouling of Air Cooled Condensers On the Air Side

Matune, Nicholas J. 04 June 2012 (has links)
No description available.
254

Optimal and suboptimal terminal guidance laws with practical considerations for a short range missile against an accelerating target /

Bates, Carlton James January 1980 (has links)
No description available.
255

Qualité microbiologique de l'air et de la litière de fumier recyclé en production laitière

Duquette-Lozeau, Karine 20 December 2019 (has links)
La litière de fumier recyclé (LFR) (séparation du fumier et fraction solide remise sous les animaux) est de plus en plus utilisée dans l’industrie laitière au Québec. Pourtant, les risques reliés à son utilisation sur la santé humaine sont méconnus. La présente étude tente donc d’identifier la meilleure méthode de compostage de la LFR quant à la qualité de l’air dans les fermes laitières. Quatre méthodes de compostage du solide ont été testées : SW) statique; TW) retourné quotidiennement; DC24) statique après 24 h dans un composteur rotatif; et DC72) statique après 72 h dans un composteur rotatif. Des échantillons d’air ont été prélevés aux jours 0, 5, 10 à l’aide d’un échantillonneur liquide et d’un autre sur filtre. Les poussières ont été mesurées par compteur optique de particules. Les microorganismes ont été analysés par culture (bactéries et moisissures mésophiles, moisissures thermotolérantes) ou par qPCR pour les bactéries totales et Penicillium/Aspergillus, ainsi que plusieurs agents pathogènes et un gène de résistance aux carbapénèmes. Au jour 0, les poussières et les moisissures mésophiles sont inférieures pour SW, TW et DC24. Les bactéries totales sont plus faibles pour SW et TW et Penicilium/Aspergillus pour DC24. Au jour 5, les poussières sont inférieures pour DC24 et DC72, alors que les moisissures mésophiles, bactéries totales et Penicillium/Aspergillus sont en plus faibles concentrations pour SW et TW. Au jour 10, les poussières et Penicillium/Aspergillus sont plus faibles pour SW et TW, les bactéries totales pour DC72 et les résultats ne diffèrent pas pour les moisissures mésophiles. Pour les trois journées d’échantillonnage, SW a des concentrations inférieures à DC72 en bactéries mésophiles. Aucun des résultats de moisissures thermotolérantes ni d’endotoxines ne diffère et aucun des agents pathogènes ni le gène de résistance n’a été détecté par qPCR. Les traitements SW et TW semblent représenter les meilleurs choix quant à la qualité de l’air. / Recycled manure solids (RMS) (solid-liquid separation f fresh manure where the solid fraction is used as bedding) gain rising interest in Quebec’s dairy industry. However, RMS use’s associated risks on human and animal health are unknown. This study tried to identify the best composting method regarding to air quality in dairy barns. Four composting methods were tested: SW) static, TW) daily turned, DC24) static after 24 h in a drum composter and DC72) static after 72 h in a drum composter. Air sampling were done with a liquid sampler and a filter sampler at days 0, 5 and 10. Dust concentrations were measured by an optical particle counter. Microorganisms were analysed by culture (mesophilic bacteria and fungi, thermotolerant fungi) or by qPCR for total bacteria (16s rDNA) and Penicillium/Aspergillus (ITS1), as well for several pathogenic agents and a carbapeneme resistance gene (KPC). At day 0 and 5, SW, TW and DC24 lead to the lowest concentrations for dust and mesophilic fungi. Total bacteria were lower for SW and TW, while Penicillium/Aspergillus were lower for DC24. At day 5, DC24 and DC72 lead to the lowest concentrations for dust, while SW and TW lead to lower concentrations for mesophilic fungi, total bacteria and Penicillium/Aspergillus. At day 10, dust and Penicillium/Aspergillus were lower for SW and TW, while total bacteria were lower for DC72 and no mesophilic fungi did not differ. For the three sampling days, SW lead to lower concentration of mesophilic bacteria than DC72. No thermotolerant fungi or endotoxins results differ and no pathogenic agent or the carbapenem resistance gene were detected by qPCR. Thus, SW and TW seem to be the methods to privilege regarding air quality in dairy barns.
256

Studies of the fungus content of the air

Bhatti, M. Abdur Razzaque January 2011 (has links)
Digitized by Kansas State University Libraries
257

Air movement and energy flows in an air-conditioned and partitioned industrial environment

Pitts, Adrian C. January 1986 (has links)
This study concerns an investigation into air movement and associated energy flows within the environment of a synthetic fibre producing factory. A multiplicity of airconditioning and ventilation systems were operated within the factory to provide a suitable atmosphere for the yarn, and also to allow some degree of comfort in hot production areas. Potential for improved operation of these systems was anticipated. Initial experiments showed certain anomalies and problems relating to air conditions and air movement; and an important facet of the production areas was identified as the regular partitioning created by the machine layout. A review of previous studies of building air flows indicated a lack of information relating to industrial and partitioned areas. Mathematical relationships for air flows were studied and the interactions of similar, closely spaced partitions were considered. A series of model scale tests using simple layouts supported a theory of interaction. The effect was substantial for wall type partitions and a considerable overestimation could result from the simple additive approach to determination of total resistance. At the factory a computer based monitoring scheme was designed and installed in order to establish environmental conditions and energy flows. The concept of "total thermal efficiency" was developed as a means of evaluating the performance of some of the air-conditioning systems. Considerable variations were evident between seasons and between systems; improvements being possible and recommended. Air flows were also investigated using Nitrous Oxide as a tracer gas. The effect of the internal partitioning combined with the high degree of ventilation and air-conditioning was to "compartmentalize" the spaces between the machines in the production areas, semi-isolating each from its neighbours. Thus, the results of the simplified model scale work could not be applied directly. However the isolation of the spaces offers potential for better systems operation by reducing air-conditioning requirements.
258

Performance studies of externally pressurized air thrust bearings

何光偉, Ho, Kwong-wai. January 1976 (has links)
published_or_final_version / Industrial Engineering / Master / Master of Philosophy
259

A study of thermally-induced Meso-scale airflows over inhomogeneous terrain

Li, Jain-Guo January 1997 (has links)
No description available.
260

The design and development of devices for aerial pollution abatement

Lewis, Andrew January 2002 (has links)
No description available.

Page generated in 0.0322 seconds