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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.
51

Time-resolved study of third harmonic generation from anisotropically expanding clusters

Shim, Bonggu 28 August 2008 (has links)
Not available / text
52

K-Ar relationships in a Cambrian shale as a function of burial depth

Sedivy, Robert Alan 12 1900 (has links)
No description available.
53

Pulse shape discrimination studies in liquid argon for the DEAP-1 detector

Lidgard, Jeffrey Jack 25 April 2008 (has links)
A detector with a target mass of 7 kg of liquid argon was designed, constructed and operated at Queen’s University. This detector is a scaled model for the DEAP project toward a tonne-scale argon detector to search for the WIMP candidate of the so far undetected, dark matter of the universe. The primary intent of the scaled detector was to measure the achievable level to reject background events by use of pulse shape discrimination, being based upon the scintillation timing properties of liquid argon. After refining the apparatus and components, the detector was in operation from the 20th of August until the 16th of October 2007 before being moved to its current location in SNOLAB. During this time, a population of 31 million well-tagged gamma events were collected, of which 15.8 million were in the energy range of interest for calibration. This population was sufficient to demonstrate the discrimination of background events by pulse shape discrimination at the level of 6.3 × 10-8. An analytical model was constructed, based on the scintillation processes and detector response, and has been sufficiently investigated to make predictions of further achievable discrimination. / Thesis (Master, Physics, Engineering Physics and Astronomy) -- Queen's University, 2008-04-25 01:39:39.121
54

Vapor-liquid phase equilibria of the binary system argon-helium

McCain, William David 05 1900 (has links)
No description available.
55

Carbothermal synthesis of titanium oxycarbide

Dewan, Mohammad Ashikur Rahman, Materials Science & Engineering, Faculty of Science, UNSW January 2009 (has links)
The aim of the project was to establish the rate and mechanisms of solid stage reduction of titania and ilmenite ores. The project examined carbothermal reduction of titania and various types of ilmenite ores in argon, helium, hydrogen, and their mixtures. Effect of CO in the gas atmosphere on reduction behavior of titania and primary ilmenite ore was also studied. Isothermal and non-isothermal reduction experiments were conducted in a fixed bed reactor in the high temperature furnace in the temperature range up to 1500oC. The off-gas composition in the reduction process was monitored by a CO/CO2/CH4 infrared analyser. The extent of reduction was calculated using data on gas composition and LECO oxygen analysis. Phase composition and morphology of reduced samples were studied using XRD, SEM and optical microscopy. The major findings of this project are as follows: • The reduction of titania to titanium oxycarbide occurred in the following sequence: TiO2 → Ti5O9 → Ti4O7 → Ti3O5 → Ti2O3 → (TiO-TiC) solid solution. • Carbothermal reduction of ilmenite concentrates proceeded in two main stages. In the first stage pseudorutile and ilmenite were reduced to metallic iron and titania. Second stage involved the reduction of titania to titanium oxycarbide. • Rate and degree of reduction of titania and ilmenite concentrates increased with increasing temperature. • Reduction rate of titania and ilmenite concentrates was faster in hydrogen than in helium and argon. The difference in the reduction behavior in helium and argon was insignificant; reduction rate of ilmenite was slightly faster in helium than in argon. • High rate of reduction of titania and ilmenite in hydrogen was attributed to formation of methane which facilitated mass transfer of carbon from graphite to oxide. Hydrogen was also directly involved in reduction of titania and ilmenite concentrates; hydrogen reduced pseudorutile to iron and titania. Titania was further reduced to titanium oxycarbide by carbon through methane. • Increased gas flow rate slightly improved the reduction rate in hydrogen and suppressed the reduction in inert gases. • Addition of CO to hydrogen and inert gases above 3 vol% suppressed the reduction process.
56

Carbothermal synthesis of titanium oxycarbide

Dewan, Mohammad Ashikur Rahman, Materials Science & Engineering, Faculty of Science, UNSW January 2009 (has links)
The aim of the project was to establish the rate and mechanisms of solid stage reduction of titania and ilmenite ores. The project examined carbothermal reduction of titania and various types of ilmenite ores in argon, helium, hydrogen, and their mixtures. Effect of CO in the gas atmosphere on reduction behavior of titania and primary ilmenite ore was also studied. Isothermal and non-isothermal reduction experiments were conducted in a fixed bed reactor in the high temperature furnace in the temperature range up to 1500oC. The off-gas composition in the reduction process was monitored by a CO/CO2/CH4 infrared analyser. The extent of reduction was calculated using data on gas composition and LECO oxygen analysis. Phase composition and morphology of reduced samples were studied using XRD, SEM and optical microscopy. The major findings of this project are as follows: • The reduction of titania to titanium oxycarbide occurred in the following sequence: TiO2 → Ti5O9 → Ti4O7 → Ti3O5 → Ti2O3 → (TiO-TiC) solid solution. • Carbothermal reduction of ilmenite concentrates proceeded in two main stages. In the first stage pseudorutile and ilmenite were reduced to metallic iron and titania. Second stage involved the reduction of titania to titanium oxycarbide. • Rate and degree of reduction of titania and ilmenite concentrates increased with increasing temperature. • Reduction rate of titania and ilmenite concentrates was faster in hydrogen than in helium and argon. The difference in the reduction behavior in helium and argon was insignificant; reduction rate of ilmenite was slightly faster in helium than in argon. • High rate of reduction of titania and ilmenite in hydrogen was attributed to formation of methane which facilitated mass transfer of carbon from graphite to oxide. Hydrogen was also directly involved in reduction of titania and ilmenite concentrates; hydrogen reduced pseudorutile to iron and titania. Titania was further reduced to titanium oxycarbide by carbon through methane. • Increased gas flow rate slightly improved the reduction rate in hydrogen and suppressed the reduction in inert gases. • Addition of CO to hydrogen and inert gases above 3 vol% suppressed the reduction process.
57

A versatile molecular beam apparatus utilizing electron bombardment detection observation of the rainbow effect for argon-nitrogen /

Bickes, Robert W. January 1970 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1970. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.
58

Time-resolved study of third harmonic generation from anisotropically expanding clusters

Shim, Bonggu, January 1900 (has links) (PDF)
Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.
59

Étude des écarts à l'équilibre thermodynamique local complet dans un arc d'argon à la pression atmosphérique.

Gomes, Anne-Marie Lautier, January 1900 (has links)
Th.--Sci. phys.--Toulouse 3, 1978. N°: 847.
60

Potassium-argon age determinations on biotites and amphiboles, Bethlehem Copper Property, B.C.

Dirom, Gavin Ewan January 1965 (has links)
Potassium-argon apparent ages obtained on biotite and amphibole from various phases of the Guichon Creek batholith present on the Bethlehem Copper property are reported and their geological significances are discussed in this thesis. Although the individual phases were found to be essentially indistinguishable in terms of their potassium-argon apparent ages, the results obtained indicated with considerable certainty that these phases were emplaced during an interval not greater than 10 m.y. centered around 200 m.y. ago and that no major metamorphic event has occurred in this area since this time. It is also believed that this average apparent age of 200 m.y. may represent a better approximation to the maximum age of the Triassic-Jurassic boundary than that previously reported in the literature. The potassium and argon analytical techniques employed are described briefly, and the analytical precision and accuracy obtained are discussed. Descriptions of the samples collected and samples analyzed are given as an appendix. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

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