1,808 research outputs found

    Aspects of economic restructuring in Canada, 1989-1994

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    The way in which Canadian firms produce goods and services has changed dramatically during the 1990s. A major feature of this restructuring has been a shift towards greater use of capital goods, particularly computer-based technology, relative to labour in production processes. The author examines this phenomenon from a macroeconomic perspective, identifying the principal factors behind the trends in investment and employment since the late 1980s. The analysis focusses on the relative costs of capital and labour over the period and on their implications for output and employment.

    An Evaluation of Fixed Announcement Dates

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    When it launched a new system for regularly announcing its decisions regarding the overnight rate of interest in December 2000, the Bank of Canada had a number of key objectives in mind. These included reduced uncertainty in financial markets, greater focus on the Canadian rather than the U.S. economic environment, more emphasis on the medium-term perspective of monetary policy, and increased transparency regarding the Bank's interest rate decisions. Evidence to date suggests that all four objectives have been met to a substantial degree. Fixed announcement dates have provided regular opportunities for the Bank to communicate its views on the state of the Canadian economy to the public. This has helped to improve understanding of the broad direction of monetary policy and of the rationale behind the Bank's policy decisions although the decisions themselves are not always fully anticipated.

    Temperature Transients of Fusion-fission Hybrid Reactors in Loss of Coolant Accidents

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    Field Evaluation of Herbicides on Small Fruit, Vegetable, and Ornamental Crops, 1997

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    Growers generally use herbicides to efficiently produce high-quality fruit and vegetables for processing or fresh market sales. Due to the smaller acreage of these crops compared to major field crops, fewer herbicides are registered for use in fruit and vegetable crops than for field crops. Each year, new herbicides are evaluated under Arkansas growing conditions with the objective of improving the herbicide technology for the grower, processor, and ultimately the consumer. This report includes studies on the control of many of the more serious weed problems in important crops of this region, including snapbeans, spinach, southern pea, watermelon, cantaloupe, tomato, blackberry, and grape. In addition, the report includes information on the tolerance of selected bedding plants to some effective herbicides

    Functional requirements document for the Earth Observing System Data and Information System (EOSDIS) Scientific Computing Facilities (SCF) of the NASA/MSFC Earth Science and Applications Division, 1992

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    Five scientists at MSFC/ESAD have EOS SCF investigator status. Each SCF has unique tasks which require the establishment of a computing facility dedicated to accomplishing those tasks. A SCF Working Group was established at ESAD with the charter of defining the computing requirements of the individual SCFs and recommending options for meeting these requirements. The primary goal of the working group was to determine which computing needs can be satisfied using either shared resources or separate but compatible resources, and which needs require unique individual resources. The requirements investigated included CPU-intensive vector and scalar processing, visualization, data storage, connectivity, and I/O peripherals. A review of computer industry directions and a market survey of computing hardware provided information regarding important industry standards and candidate computing platforms. It was determined that the total SCF computing requirements might be most effectively met using a hierarchy consisting of shared and individual resources. This hierarchy is composed of five major system types: (1) a supercomputer class vector processor; (2) a high-end scalar multiprocessor workstation; (3) a file server; (4) a few medium- to high-end visualization workstations; and (5) several low- to medium-range personal graphics workstations. Specific recommendations for meeting the needs of each of these types are presented

    Space Launch System Base Heating Test: Tunable Diode Laser Absorption Spectroscopy

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    This paper describes the Tunable Diode Laser Absorption Spectroscopy (TDLAS) measurement of several water transitions that were interrogated during a hot-fire testing of the Space Launch Systems (SLS) sub-scale vehicle installed in LENS II. The temperature of the recirculating gas flow over the base plate was found to increase with altitude and is consistent with CFD results. It was also observed that the gas above the base plate has significant velocity along the optical path of the sensor at the higher altitudes. The line-by-line analysis of the H2O absorption features must include the effects of the Doppler shift phenomena particularly at high altitude. The TDLAS experimental measurements and the analysis procedure which incorporates the velocity dependent flow will be described

    Scaled Rocket Testing in Hypersonic Flow

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    NASA's Space Launch System (SLS) uses four clustered liquid rocket engines along with two solid rocket boosters. The interaction between all six rocket exhaust plumes will produce a complex and severe thermal environment in the base of the vehicle. This work focuses on a recent 2% scale, hot-fire SLS base heating test. These base heating tests are short-duration tests executed with chamber pressures near the full-scale values with gaseous hydrogen/oxygen engines and RSRMV analogous solid propellant motors. The LENS II shock tunnel/Ludwieg tube tunnel was used at or near flight duplicated conditions up to Mach 5. Model development was strongly based on the Space Shuttle base heating tests with several improvements including doubling of the maximum chamber pressures and duplication of freestream conditions. Detailed base heating results are outside of the scope of the current work, rather test methodology and techniques are presented along with broader applicability toward scaled rocket testing in supersonic and hypersonic flow
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