73,238 research outputs found
Carrying Canadian Troops: The Story of RMS \u3cem\u3eOlympic\u3c/em\u3e as a First World War Troopship
In the long adventurous life of Royal Mail Ship (RMS) Olympic, the older sister of the ill-fated RMS Titanic, the time she spent as a troopship ferrying Canadian troops during the First World War is a notable but frequently overlooked part of her career. Olympic was cheered enthusiastically by Canadian troops who sailed aboard her, respected as the “Old Reliable,” praised for services rendered to other ships, and honoured for her own success in attacking an enemy submarine. Carrying more Canadian soldiers than any other troopship, Olympic was an important part of Canada’s war effort.
Able to accommodate close to 6000 troops at a time, Olympic made ten round trips from Liverpool to Halifax between March and December 1916. On the return voyages she carried wounded soldiers and civilians back to Canada. For the next two years Olympic continued to ferry Canadian and American troops across the Atlantic, and in 1919, brought the victorious soldiers home. Although she was once a household name in Canada, Olympic’s wartime service has since slipped into obscurity.
Most information on Olympic as a troopship is derived from the memoirs of the Olympic’s wartime Captain, Sir Bertram Hayes. Using Hayes’s account as a framework, this article helps to further illuminate Olympic’s wartime history with new material such as diaries, and other sources housed at the National Archives of Canada and at the hitherto largely untapped Archives of the Canadian War Museum. These sources provide interesting details of the experiences of sailing on the vessel and of life on board, including the difficulties of embarkation and disembarkation, the danger from submarines, and the general supply and handling of this large ship in frequently hazardous circumstances
The promise of eutectics for aircraft turbines
The current status of the first generation eutectics, gamma/gamma transition - delta and NiTaC-13, is described in detail. Several second generation systems, such as gamma/gamma transition - alpha and NiTaC 3-116A, gamma - beta, and COTAC 74 are also reviewed with particular emphasis on their critical physical and mechanical properties, future research directions, and potential applications. Results of recent cost-benefit analyses of eutectic turbine blades are discussed
A management model for selecting major subcontractors in the aerospace industry
Management model for selecting major subcontractors in aerospace industr
Hydrogen environment embrittlement
Hydrogen embrittlement is classified into three types: internal reversible hydrogen embrittlement, hydrogen reaction embrittlement, and hydrogen environment embrittlement. Characteristics of and materials embrittled by these types of hydrogen embrittlement are discussed. Hydrogen environment embrittlement is reviewed in detail. Factors involved in standardizing test methods for detecting the occurrence of and evaluating the severity of hydrogen environment embrittlement are considered. The effect of test technique, hydrogen pressure, purity, strain rate, stress concentration factor, and test temperature are discussed. Additional research is required to determine whether hydrogen environment embrittlement and internal reversible hydrogen embrittlement are similar or distinct types of embrittlement
Electron Transfer in Proteins
Electron-transfer (ET) reactions are key steps in a diverse array of biological transformations ranging from photosynthesis to aerobic respiration. A powerful theoretical formalism has been developed that describes ET rates in terms of two parameters: the nuclear reorganization [lambda] energy (1) and the electronic-coupling strength (HAB). Studies of ET reactions in ruthenium-modified proteins have probed [lambda] and HAB in several metalloproteins (cytochrome c, myoglobin, azurin). This work has shown that protein reorganization energies are sensitive to the medium surrounding the redox sites and that an aqueous environment, in particular, leads to large reorganization energies. Analyses of electronic-coupling strengths suggest that the efficiency of long-range ET depends on the protein secondary structure: [beta]sheets appear to mediate coupling more efficiently than [alpha]-helical structures, and hydrogen bonds play a critical role in both
AdS Strings with Torsion: Non-complex Heterotic Compactifications
Combining the effects of fluxes and gaugino condensation in heterotic
supergravity, we use a ten-dimensional approach to find a new class of
four-dimensional supersymmetric AdS compactifications on almost-Hermitian
manifolds of SU(3) structure. Computation of the torsion allows a
classification of the internal geometry, which for a particular combination of
fluxes and condensate, is nearly Kahler. We argue that all moduli are fixed,
and we show that the Kahler potential and superpotential proposed in the
literature yield the correct AdS radius. In the nearly Kahler case, we are able
to solve the H Bianchi using a nonstandard embedding. Finally, we point out
subtleties in deriving the effective superpotential and understanding the
heterotic supergravity in the presence of a gaugino condensate.Comment: 42 pages; v2. added refs, revised discussion of Bianchi for N
Effect of exposure cycle on hot salt stress corrosion of a titanium alloy
The influence of exposure cycle on the hot-salt stress-corrosion cracking resistance of the Ti-8Al-1Mo-1V alloy was determined. Both temperature and stress were cycled simultaneously to simulate turbine-powered aircraft service cycles. Temperature and stress were also cycled independently to determine their individual effects. Substantial increases in crack threshold stresses were observed for cycles in which both temperature and stress or temperature alone were applied for 1 hour and removed for 3 hours. The crack threshold stresses for these cyclic exposures were twice those determined for continuous exposure for the same total time of 96 hours
P/M superalloys: A troubled adolescent?
The history of powder metallurgy P/M superalloy technology is reviewed with a comment on the state of the art, and speculates on the technology's future potential growth and maturity
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