19,079 research outputs found

    Confronting Technological and Tactical Change: Allied Anti-Submarine Warfare in the Last Year of the Battle for the Atlantic

    Get PDF
    The recall of German U-boat wolfpacks from the central north Atlantic at the end of May 1943 ended the most costly phase of the shipping war for the Allies. Never again would the German U-boats inflict dangerously high shipping losses. The naval war remained bitter, nonetheless, for the U-boats refused to give up, turning instead to new technology and new tactics. Right to the end, they continued to present a plausible threat that caused concern in high Allied circles. Indeed, in January 1945 the First Sea Lord of the Admiralty was moved to warn that, “The high shipping losses which may occur during the first half of 1945 may well prejudice the maintenance of our forces in Europe....” The ensuing struggle in early 1945 led to a confrontation and tactical changes by the U-boats countered by operational and tactical adaptation produced in reply by Allied anti-submarine warfare (ASW) forces. This last phase of the battle of the Atlantic was fought out for the most part in the confusing and difficult shallow waters around the coasts of the United Kingdom and off the east coast of Canada, moving to the shores of the United States only in the last few months of the war. This campaign provides insights into how new and unexpected initiatives by an enemy could be dealt with even when no technological solutions were readily at hand. It also illustrates the difficulty that both submarine and antisubmarine forces encounter when operating in the challenging environment of shallow water

    In-depth research into rural road crashes

    Get PDF
    This report was produced under an agreement between Transport SA and the Road Accident Research Unit formed in the late 1990s. Due to various delays in the publication of this report, Transport SA has since become the Department for Transport, Energy and Infrastructure and the Road Accident Research Unit has become the Centre for Automotive Safety Research. The report describes a series of 236 rural road crashes investigated between 1 March 1998 and 29 February 2000 in South Australia. Investigations began with immediate attendance at the scene of the crash. The information collected for each crash included: photographs of the crash scene and vehicles involved, video record of the crash scene and vehicles in selected cases, examination of the road environment, a site plan of the crash scene and vehicle movements in the crash, examination and measurements of the vehicles involved, interviews with crash participants, interviews with witnesses, interviews with police, information on the official police report, information from Coroner’s reports, and injury data for the injured crash participants. The report provides an overall statistical summary of the sample of crashes investigated, followed by a detailed examination of the road infrastructure issues contributing to the crashes. This is done on the basis of crash type, with separate sections concerned with single vehicle crashes, midblock crashes and crashes at intersections. A section is also provided that examines the role of roadside hazards in the crashes.Baldock MRJ, Kloeden CN and McLean A

    Transient thermal analysis of a data centre cooling system under fault conditions

    Get PDF
    Data centres housing the IT infrastructure of large organisations constitute a considerable technical challenge to ensure 100% operational availability for mission critical IT systems. Specifying plant cooling systems to maintain suitable temperature levels and dissipate the heat generated can be carried out using industry standard design methods. However, accounting for perturbations in cooling due to failure of plant and restart of backup systems requires for faster thermal transients to be addressed than would normally be encountered in building system analysis. It is in this context that this paper describes the modelling and analysis of a 5 MW chilled water cooling system used for the cooling of a recently constructed UK data centre. The model has been developed using the TRNSYS software and includes a full model of the energy transfers for the data centre including chillers, hydraulic network, valve models and each of the 70 Room Air Conditioning Units. The coupling between the data centre air temperature levels and the cooler system has enabled a full assessment of the cooling system design in response to system perturbations. A number of scenarios are examined involving the failure of the chillers and how the inherent thermal inertia of the system plus additional inertia achieved through buffer vessels allowed a suitable design to be achieved. The detailed transient analysis model allowed the sizing of these vessels effectively and to gain a better understanding of the chilled water plant operation, both in normal conditions and in the case of failure

    Wireworm Control using Fodder Rape and Mustard – evaluating the use of brassica green manures for the control of wireworm (Agriotes spp.) in organic crops

    Get PDF
    In a field experiment at ADAS Pwllpeiran in 2001, brassica green manures were grown for 6 weeks and dug in before planting King Edward potatoes, to see if they suppressed wireworm in the crop. There was a trend for potatoes grown after mustard to suffer less damage from both wireworms and slugs than potatoes grown after fodder rape or no green manure, but the differences were not significant. Further trials, with longer green manuring periods, are needed to establish if there is a benefit, and whether the breakdown products of brassica green manures are toxic to wireworms

    The use of Bioceramics as root-end filling materials in periradicular surgery: a literature review

    Get PDF
    Introduction: Periradicular surgery involves the placement of a root-end filling following root-end resection, to provide an apical seal to the root canal system. Historically several materials have been used in order to achieve this seal. Recently a class of materials known as Bioceramics have been adopted. The aim of this article is to provide a review of the outcomes of periradicular surgery when Bioceramic root-end filling materials are used on human permanent teeth in comparison to “traditional” materials. Methods & results: An electronic literature search was performed in the databases of Web of Science, PubMed and Google Scholar, between 2006 and 2017, to collect clinical studies where Bioceramic materials were utilised as retrograde filling materials, and to compare such materials with traditional materials. In this search, 1 systematic review and 14 clinical studies were identified. Of these, 8 reported the success rates of retrograde Bioceramics, and 6 compared treatment outcomes of mineral trioxide aggregate (MTA) and traditional cements when used as root-end filling materials. Conclusion: Bioceramic root-end filling materials are shown to have success rates of 86.4–95.6% (over 1–5 years). Bioceramics has significantly higher success rates than amalgam, but they were statistically similar to intermediate restorative material (IRM) and Super ethoxybenzoic acid (Super EBA) when used as retrograde filling materials in apical surgery. However, it seems that the high success rates were not solely attributable to the type of the root-end filling materials. The surgical/microsurgical techniques and tooth prognostic factors may significantly affect treatment outcome

    Australian Growth: A California Perspective

    Get PDF
    Examination of special cases assists understanding of the mechanics of long-run economic growth more generally. Australia and California are two economies having the rare distinction of achieving 150 years of sustained high and rising living standards for rapidly expanding populations. They are suitable comparators since in some respects they are quite similar, especially in their initial conditions in the mid-nineteenth century, their legal and cultural inheritances, and with respect to some long-term performance indicators. However, their growth trajectories have differed markedly in some sub-periods, and over the longer term with respect to the growth in the size of their economies. Most important, the comparison of an economy that remained a region in a much larger national economy with one that evolved into an independent political unit helps identify the role of several key policies. California had no independent monetary policy, or exchange rate, or controls over immigration or capital movements, or trade policy. Australia did, and after 1900 pursued an increasingly interventionist and inward-oriented development strategy until the 1970s. What difference did this make to long-run growth? And what other factors, exogenous and endogenous, account for the differences that have emerged between two economies that shared such similar initial conditions?

    The DART-Europe project: towards developing a European theses portal

    Get PDF
    This paper will report on the new European theses project DART-Europe. The purpose of this project is to align institutional and national e-theses developments across Europe with the wider open archives movement by the construction of a European portal for research theses, thus enabling a global view of European institutional research assets. This project is driven through an innovative partnership between an information provider and an international body of university libraries and open access consortia. The project’s goal is to explore the creation of a European model for the deposit, discovery, use and long-term care of research theses in an open access environment. The paper will outline the projected outcomes of DART-Europe, which is an active group of institutions in addition to a technical service. To this end, DART-Europe is engaged with disciplines and institutions that are widening the definition of research by redefining the formats of theses. For institutions and countries without a repository infrastructure, DART-Europe will enable the creation of a depository. Institutions and countries with a repository infrastructure can engage with DART-Europe to deliver their e-theses. DART-Europe acts as a technology bridge for researchers between those who have existing infrastructures and those who do not. The DART-Europe architecture assumes free at point of use access to full text theses, whether held on the DART-Europe server or by institutional repositories. This paper will provide session attendees with the current progress of this initiative, including a report on the 5 strands of the project, including: architecture; creation of a management tool kit; content acquisition; digital preservation and an investigation of business models

    The use of feed blocks as supplementation for the upland hill flock: (2) Cost effective lamb production

    Get PDF
    This report was presented at the UK Organic Research 2002 Conference of the Colloquium of Organic Researchers (COR).Under EU organic livestock regulations introduced in 2000, new restrictions were placed on the use of bought-in feedstuffs in hill systems. These reduced the non-organic annual percentage previously allowed in LFAs from 20% to 10% of annual dry matter intake. A further stepping down of these allowances may be introduced ahead of a complete ban in 2005. Bought-in feed supplements must therefore, be used strategically and offer “best value for money” in terms of ewe performance and lamb growth. The economic cost of supplementing the diet of twin-rearing ewes post lambing with either an approved non-organic feed block + half ration of commercial concentrate mix (B+CCM) or full ration commercial concentrate mix (CCM) was investigated. Lambs reared by ewes receiving the B+CCM diet had a greater liveweight gain than those reared by ewes receiving the CCM diet per kg of ewe supplementary feed. The costs in terms of kg lamb liveweight were lower for the B+CCM ewes than the CCM ewe

    Eight years of organic farming at Pwllpeiran – livestock production and the financial performance of organic upland

    Get PDF
    This report was presented at the UK Organic Research 2002 Conference. Established for 8 years, this project evaluates the practicalities of organic beef and sheep production on an upland farm in an ESA. Grassland productivity, stocking rates and animal performance are closely related to seasonal variations in the clover content of the small area of improved land. Improving sales have been offset by increasing input costs. Subsidy payments assist financial performance, but ESA prescriptions effectively prevent increased production
    corecore