8,917 research outputs found

    Single action separation mechanism Patent

    Get PDF
    Separation mechanism for use between stages of multistage rocket vehicle

    Electrical characterization Of SiGe thin films

    Get PDF
    An apparatus for measuring electrical resistivity and Hall coefficient on both thin films and bulk material over a temperature range of 300K to 1300K has been built. A unique alumina fixture, with four molybdenum probes, allows arbitrarily shaped samples, up to 2.5 cm diameter, to be measured using van der Pauw's method. The system is fully automated and is constructed with commercially available components. Measurements of the electrical properties of doped and undoped Si-Ge thin films, grown by liquid phase epitaxy reported here, are to illustrate the capabilities of the apparatus

    Controls on Cyclic Formation of Quaternary Early Diagenetic Dolomite

    Get PDF
    The origin of sedimentary dolomite and the factors that control its formation within the geological record remain speculative. In most models, dolomite formation is linked to evaporative conditions, high water temperature, increasing Mg/Ca ratio, increasing alkalinity, and high amounts of biomass. Here we challenge these archetypal views, by documenting a case example of Quaternary dolomite which formed in Lake Van at constantly low temperature (<4°C) and without direct control of the latter conditions. Dolomite occurs within highstand sediments related to suborbital climate variability (Dansgaard‐Oeschger cycles). We propose that dolomite precipitation is a product of a microbially influenced process, triggered by ecological stress, resulting from reventilation of the water‐sediment interface. Independently from the validity of this hypothesis, our results call for a reevaluation of the paleoenvironmental conditions often invoked for early diagenetic dolomite‐rich intervals within sedimentary sequences and for caution when interpreting time series of subrecent lacustrine carbonates

    Networks among British Immigrants and Accomodation to Canadian Society: Winnipeg, 1900-1914

    Get PDF
    Recently scholars have begun to explain migration in terms of the mechanisms which immigrants employ as groups to accommodate to new societies. Upon arrival in Canada, British immigrants established a new set of social relationships still strongly informed by their pre-emigration culture. The most important social institution facilitating accommodation was the nuclear family. Families were the basis for networks providing reliable information, emotional solace and material support. Other institutions flourishing in British immigrant communities — churches, benefit societies and boarding-houses — functioned as surrogate families. Networks gave the British a competitive advantage in Canada's heterogeneous society. On a commencĂ© Ă  expliquer la migration en terme de mĂ©canismes d’adaptation des groupes d'immigrants. À leur arrivĂ©e au Canada, les immigrants britanniques y ont Ă©tabli un nouveau mode de relations sociales fondĂ© en grande partie, en fait, sur leur culture d’origine. La famille nuclĂ©aire fut la plus importante des institutions sociales facilitant l’adaptation des immigrants. Elle leur fournit des informations provenant de sources fiables, un rĂ©confort affectif et un support matĂ©riel. D’autres institutions fleurissant dans la communautĂ© britannique — les Ă©glises, les sociĂ©tĂ©s de bienfaisance et les maisons d’accueil — fonctionnĂšrent comme des substituts aux familles. Ces rĂ©seaux mirent les britanniques dans une position plus compĂ©titive Ă  l’intĂ©rieur de la sociĂ©tĂ© hĂ©tĂ©rogĂšne canadienne

    The Political Economy of Bison Management in Wood Buffalo National Park

    Get PDF
    Nearly a century ago government initiatives saved Canada's wild bison from extinction, and in the 1920s Wood Buffalo National Park (WBNP) was established as a preserve for wood and plains bison. Today new government initiatives threaten these northern bison with extermination as a "game management" strategy. This paper outlines the history of bison management in WBNP and addresses critical issues for the 1990s. It is argued that until the mid-1960s, when the park came under the jurisdiction of Parks Canada, management strategies were presented as biologically based but were conditioned by external political and economic considerations. Similarly, an analysis of current proposals to "replace" the bison of WBNP concludes the contemporary issues of political economy are obscured by attempts to justify the plan on biological grounds.Key words: bison, game management, Wood Buffalo National Park, political economy, EARP, tuberculosis, brucellosisR&Eacute;SUM&Eacute;. Il y a presque un si&egrave;cle, des mesures instaur&eacute;es par le gouvernement ont emp&ecirc;ch&eacute; la disparition du bison sauvage canadien et, durant les ann&eacute;es 20, le parc national Wood Buffalo a &eacute;t&eacute; cr&eacute;&eacute; en tant que r&eacute;serve int&eacute;grale pour le bison des bois et le bison des plaines. Aujourd&rsquo;hui, de nouvelles mesures prises par le gouvernement dans le cadre d&rsquo;une strat&eacute;gie d&rsquo;am&eacute;nagement cyn&eacute;g&eacute;tique menacent ces bisons du Nord de disparition compl&egrave;te. Cet article retrace l&rsquo;historique de la conservation du bison dans le parc national Wood Buffalo et traite des enjeux critiques des ann&eacute;es 90. Il soutient que, jusqu&rsquo;au milieu des ann&eacute;es 60, lorsque le parc a commenc&eacute; &agrave; faire partie de Parcs Canada, les strat&eacute;gies de conservation &eacute;taient mises de l&rsquo;avant sur des bases biologiques mais qu&rsquo;elles &eacute;taient en fait conditionn&eacute;es par des consid&eacute;rations politiques et &eacute;conomique. De la m&ecirc;me fa&ccedil;on, une analyse des propositions actuelles visant &agrave; remplacer le bison du parc national Wood Buffalo nous am&egrave;ne &agrave; conclure que les enjeux actuels d&rsquo;&eacute;conomie politiques ont brouill&eacute;s par la tentative de justifier ces propositisounrs des bases biologiques.Mots cl&eacute;s: bison, am&eacute;nagement cyn&eacute;g&eacute;tique, parc national Wood Buffalo, &eacute;conomie politique, PEEE, tuberculose, brucellos
    • 

    corecore