• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 338
  • 125
  • 25
  • 25
  • 23
  • 10
  • 7
  • 6
  • 4
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • Tagged with
  • 681
  • 681
  • 188
  • 156
  • 149
  • 129
  • 110
  • 86
  • 84
  • 84
  • 83
  • 67
  • 59
  • 55
  • 52
  • 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.
51

Correlation Studies of Cosmic Ray Flux and Atmospheric and Space Weather

Dayananda, Mathes A 18 December 2013 (has links)
Since 1950's there has been a growing interest of understanding the effects of cosmic ray radiation on the increase in average global temperature. Recent studies showed that galactic cosmic rays play a significant role in the formation of low cloud coverage and its consequent impact on the global temperature variation of the earth. A long-term measurement of the cosmic ray flux distribution at the surface of the earth has been established at Georgia State University. The current effort is focused on understanding the correlations between the cosmic ray particle flux distribution and the atmospheric and space weather measurements. In order to understand the observed atmospheric effects on cosmic ray flux, numerical simulations of cosmic muon and neutron flux variations at the surface of the earth have been carried out with varying air densities in the troposphere and stratosphere based on the Geant4 package. The simulation results show a remarkably good agreement with observations. The simulation results also show that the stratosphere air density variation dominates the effects on the muon flux changes while the density variation in the troposphere mainly influences the neutron count variation. This suggests that the long-term variation of muon flux could possibly direct us to a new path to understand the global climate warming trend.
52

Photolysis of 2-pentyl nitrite : quantum yield and relevance to atmospheric chemistry

Hussain, Altaf January 1997 (has links)
One of the remaining problems associated with the photo-degradation of organic species in the atmosphere, is concerned with the mechanisms of C<sub>5</sub> and larger fragments. In this respect the 2-pentoxy radical has been chosen as a model radical. The subsequent mechanisms for it are thought to be similar to those for all other larger species. The photolysis of 2-pentyl nitrite in the near ultraviolet (UV) region at 328-383 nm resulted in the formation of 2-pentoxy radicals and nitric oxide with the quantum yield of 0.97 ± 0.08 at 298-393K, consistent with the assumption that the quantum yield was unity for alkyl nitrites. In the present work, <I>tert-</I>butyl nitrite has been shown to be unity. The reactions of the model radical were investigated in inert (CF<sub>4</sub>), and oxygen atmospheres, by end product analysis using on-line gas-liquid chromatography. The expected reaction routes were: decomposition, oxidation (β-H atom abstraction), and 1,5-H shift isomerisation which would produce acetaldehyde, 2-pentanone and acetone respectively. Its reaction scheme was evaluated by comparing the experimental with model results, derived by the Gear Algorithm. The estimated or calculated rate constants in the literature were "brute force" adjusted to adapt the modelling results to the experimental results. Our investigations suggested, among the rate constants for the 2-pentoxy radical: k<sub>dec </sub>9.2 x 10<sup>3</sup>s<sup>-1</sup>: CH<sub>3</sub>CH(O)(CH<sub>2</sub>)<sub>2</sub>CH<sub>3</sub> → n-CH<sub>3</sub>CHO + n-C<sub>3</sub>H<sub>7, </sub>k<sub>02</sub> 7.0 x 10<sup>5</sup>M<sup>-1</sup>s<sup>-1</sup>: CH<sub>3</sub>CH(O)(CH<sub>2</sub>)<sub>2</sub>CH<sub>3</sub>+0<sub>2</sub> → CH<sub>3</sub>C(O)(CH<sub>2</sub>)<sub>2</sub>CH<sub>3</sub> + HO<sub>2</sub>, and k<sub>isom</sub> 1.4 x 10<sup>4</sup>s<sup>-1</sup>; CH<sub>3</sub>CH(O)(CH<sub>2</sub>)<sub>2</sub>CH<sub>3</sub> → CH<sub>3</sub>CH(OH)(CH<sub>2</sub>)<sub>2</sub>CH<sub>2</sub>) The 1,5-H shift isomerisation is relatively fast. The Arrhenius parameters of these rate constants were also modified.
53

Two extreme cases of atmospheric blocking over Europe and North America

Glisan, Justin Michael. January 2007 (has links)
Thesis (M.S.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on March 26, 2008) Includes bibliographical references.
54

Response of rainbow trout (Oncorhynchus mykiss) to simulated climate warming and sublethal ammonia /

Linton, Tyler K. January 1997 (has links)
Thesis (Ph.D.) -- McMaster University, 1997. / Includes bibliographical references. Also available via World Wide Web.
55

ReDesign for a new energy paradigm /

Lewton, Alexander Tripp. January 2008 (has links) (PDF)
Thesis (M Arch)--Montana State University--Bozeman, 2008. / Typescript. Chairperson, Graduate Committee: Christopher Livingston. Includes bibliographical references (leaves 97-99).
56

Promoting environmental stewardship through exhibitions : the challenge of representing global warming in science museums /

Ryan, Shelly E. January 2005 (has links)
Final Project (M.A.)--John F. Kennedy University, 2005. / "August 29, 2005"--T.p. Includes bibliographical references (p. 136-141).
57

Responding to global warming a legitimacy critique of the proposed Kyoto Protocol compliance regime /

Crossen, Teall. January 1900 (has links) (PDF)
Thesis (LL.M.)--University of Calgary (Canada), 2004. / Adviser: Alastair Lucas. Includes bibliographical references.
58

Benchmarking climate change strategies under constrained resource usage /

Nettleton, Stuart John. January 2009 (has links)
Thesis.
59

Emission estimtes for some acidifying and greenhouse gases and options for their control in Finland /

Pipatti, Riitta. January 1998 (has links) (PDF)
Thesis (D. Tech.)--Helsinki University of Technology, 1998. / Issued also in electronic form.
60

A new international environmental order? an assessment of the impact of the global warming epistemic community /

Smith, Heather A. January 1993 (has links)
Thesis (Ph. D.)--Queen's University, 1993. / Vita. Includes bibliographical references (leaves 222-238).

Page generated in 0.111 seconds