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31.
Xing Ruan 《Frontiers of Structural and Civil Engineering》2010,4(4):450-455
This essay begins with a reflection on what has been taught in architectural design since the turn of the twentieth century. I shall trace back to the two disciplinary foundations of the French École des Beaux-Arts — parti and poché — in the education of an architect in the eighteenth and nineteenth centuries. I shall then attempt to superimpose parti and poché on a modern disciplinary framework, say that of mathematics, which leads to musings on a series of architectural problems that include pattern versus type, stability versus mobility, orthogonal versus oblique, confinement versus transparency, and aging versus metallic sheen. These paradoxes, I suggest, demand the education of an architect to address both the instrumental pattern of a building configuration and the ambient felt qualities of a room, rather than vision alone. 相似文献
32.
H. Manz P. Loutzenhiser T. Frank P.A. Strachan R. Bundi G. Maxwell 《Building and Environment》2006,41(12):1784-1797
33.
Ten full-scale test fires were conducted in a chamber simulating a three person ship accommodation quarter. The test fires used three different ventilation conditions, two types of bunks and furnishings with either polyurethane foam or chloroprene foam. The chamber was instrumented to follow the development of the fire.The furnishings with polyurethane foam were readily ignited and produced an intense fire within 2 to 4 minutes. The furnishings with chloroprene foam ignited but burned slowly with a small flame or in smoldering combustion.The ventilation conditions had a significant effect on the development and intensity of the fire as the test fires were burning under oxygen-limiting conditions.The solid pan bunks retarded the early development of the fire compared to open bunks for polyurethane furnishings. However, once the mattresses on the three bunks were ignited the intensity of the test fires was similar for both types of bunks. 相似文献
34.
Spatial competition and regulatory change in the grain handling and transportation system in western Canada 总被引:2,自引:0,他引:2
The grain handling and transportation system (GHTS) has been a defining component of the western Canadian economy since the
early part of the last century. Only two major railways serve the grain handling industry, so the potential for the exercise
of market power in transportation appears to be significant. In fact, spatially oriented regulations applicable to railways
exist in Canada to mitigate this, but to date they have not often been used by shippers. While the reasons for this are not
completely clear, we suggest that the regulations are now inadequate for the current state of the GHTS. Using a unique data
set from the year 2000, we assess the effect on the grain handling industry of modifications to these regulations, and find
that significant gains for shippers from these modifications are possible. These gains are computed to be on the order of
C$10–15 million per year for grain shippers alone.
We would like to thank conference and presentation participants (Transportation Research Board, Canadian Agricultural Economics
Society, University of British Columbia, University of Leeds and California State University, Long Beach) as well as the anonymous
reviewers who commented on the earlier versions of this paper. We would also like to acknowledge support from the Saskatchewan
Department of Highways. 相似文献
35.
Finite element modelling of plate girders with web openings 总被引:1,自引:0,他引:1
This paper is concerned with a finite element model to predict the behaviour and ultimate load of plate girders with web openings. The finite element package
is used to model the plate girders with web openings. Accuracy of the model is assessed by applying it to plate girders tested earlier by other researchers. Comparison of analytical results with the available experimental results for yielding patterns, ultimate load values and load–deflection relationships show good agreement between the finite element and experimental results thus validating the accuracy of the proposed model. The proposed finite element method was extended to carry out a parametric study. The study covered parameters such as web slenderness and flange stiffness. 相似文献
36.
K. Suzuki M. Oda M. Yamazaki T. Kuwahara 《International Journal of Rock Mechanics and Mining Sciences》1998,35(7):907-921
Permeability tests and observation of induced, as well as inherent, cracks have been carried out to quantitatively explain permeability changes in granite taking place during a weathering test in terms of micro-structure by cracks. To this end, permeability tensors were estimated from observations of crack systems using the Replica Method and of the crack apertures with a scanning electron microscope. The following conclusions were reached: the drastic increase in permeability around an immersion of 1000 d in 90°C water could not be explained by the existence of a percolation threshold because all the specimens were percolative in the sense that the traces of crack tensor were above the critical density for percolation. On the other hand, SEM observation revealed that, with immersion, crack apertures widened and their distribution spread. Permeability estimated using the third (not the first) moment of observed apertures showed the increase in measured permeability well. When evaluating the connectivity parameter λ to give a quantitative accordance between measured and estimated permeability, it had a constant value as low as 0.17, irrespective of the immersion period, in spite of the higher density of micro-cracks than the percolation threshold. It can be said that, in considering the natural three-dimensional crack system, the third moment of physical apertures plays a more important role in predicting the permeability and λ is greatly affected by the spread of crack apertures. 相似文献
37.
The oxidation of protocatechuic acid with ozone in aqueous solution has been studied varying the temperature, pH, ozone partial pressure and initial acid concentration. A stoichiometric ratio of 2 mol of ozone consumed per mol of protocatechuic acid reacted is deduced from homogeneous experiments in a discontinuous tank reactor.In the ozonation experiments, the influence of the operating variables was established and the kinetic regime of ozone absorption was shown to be fast and pseudo m-order with respect to ozone, except at pH 2, when the reaction develops in the moderate kinetic regime. After applying a mass transfer with chemical reaction model, the reaction orders are deduced and the kinetic rate constants are determined as a function of pH and temperature. A modified Arrhenius expression is proposed to correlate them. 相似文献
38.
After the Chernobyl accident in April 1986, considerable deposition of radionuclides occurred regionally in eastern, central and northwestern Sweden. Locally, the fallout of radiocesium exceeded the remainder from atmospheric nuclear weapons tests by several magnitudes. Since the end of the 1960s samples of organs from various plant and animal species, annually collected at different localities, have been preserved in the Swedish Environmental Specimen Bank (ESB). In this work samples from the ESB have been used for retrospective studies of radioactive pollution. The activities of Cs-134 and Cs-137 in muscle tissues from reindeer, Rangifer tarandus, and pike, Esox lucius, preserved in the ESB, were measured. The samples were collected annually; the reindeer at three localities in northern Sweden and the pike at one of them. In material collected prior to the Chernobyl accident, the levels of Cs-137 were 57-180 Bq/kg in reindeer and 14-24 Bq/kg in pike, fresh weight basis. These levels relate to earlier nuclear bomb tests. A significant decrease was found in pike during the pre-Chernobyl period (1971-86). In post-Chernobyl samples the burden of Cs-137 varied from amounts equal to the former levels in the northernmost locality and up to 80 times higher for the maximum values in the southernmost locality. The highest value recorded was 18,425 Bq/kg in reindeer. The geographic variations in reindeer from Chernobyl fallout were in accordance with the pattern of deposition estimated by aircraft surveys performed in May 1986. The ratio between 'new' and 'old' radiocesium burdens in pike, caught in 1987, approached the corresponding ratio for reindeer grazing in the precipitation area of the lake; 33 and 19, respectively. 相似文献
39.
Data from compartment tests of polyurethane foam seating assemblies are reported. Results show that the behavior of such assemblies during fires is strongly dependent on the type and position of interliners and upholstery fabrics. An incidental comparison of peak rate of heat release obtained in a compartment test with a predictive model equation is made and selected data from the tests are presented. 相似文献
40.
In recent years the presence of haloforms has been observed by some researchers in waters of various origins.The aim of this study is to determine the conditions in which chloroform is formed by chlorination of aqueous solutions of some organic compounds.The first part of this work was carried out by chlorination of synthetic basic solutions of acetone and thus enabled us to determine the reagent concentrations needed to obtain the maximum quantity of chloroform.We studied next the effect of chlorination on organic material solutions (humic acids and phenols), in the course of an oxidation treatment; the results obtained by chlorination of aqueous solutions of humic substances show that the quantity of chloroform produced passes through a maximum value which depends on the time of ozonisation. Similar results were obtained for the chlorination of phenol solutions during oxidation by the u.v. + H2O2 system. These results may be explained by the partial degradation of the molecules which leads in the formation of reactional intermediate precursors of the haloform reaction. We undertook at the same time the study of a rapid test allowing us to detect the presence of haloform reaction precursors in a certain sample of water. 相似文献