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71.
72.
Results are recorded of topographical details, weight loss and corrosion product analysis for short-term atmospheric exposure of mild steel, in relation to weather and pollutant factors. Various structured corrosion features, e.g. doughnut-like, were noted. The major corrosion product found was γ-Fe2O3,H2O, with some α-Fe2O3,H2O and α-FeOOH.Wet initial conditions of exposure and subsequent high levels of humidity, were found to have the dominant overriding effect in promoting corrosion losses. Smoke was shown to be capable of exerting a very strong influence upon the effective corrosivity of atmospheric sulphur dioxide. 相似文献
73.
W.S. Elliott 《Computer aided design》1978,10(2):91-100
While considerable success has attended the application of CAD in the electronics, aerospace, ship, offshore structure and other industries, less progress has been reported in general mechanical engineering; yet the opportunities are great and the CAD idea started in mechanical engineering.This paper considers some of the problems in applying computer aid to the sequential processes of initial design, detailing, planning, piece-part manufacture and assembly. Recent achievements in separate parts of this process are identified, especially in modelling and in user-oriented interactive input of design parameters and insight-giving output of analysis results. Case histories are mentioned and possibilities for a cost-effective solution to the CAD/CAM problem in medium-sized engineering companies are discussed. 相似文献
74.
Streptokinase-streptodornase (SK-SD) induced immediate and delayed skin test reactions in a high proportion of patients with disorders in which beta-streptococcal infection may be involved. The P-K test and absorption experiments with antigen or anti-IgE suggested that the immediate reaction was mediated by specific IgE antibody against SK-SD. Furthermore, the ratio of specific IgE antibody against SK-SD to total IgE was roughly calculated to be 20 percent. Finally, the RAST technique was applied to detect specific IgE antibody against SK-SD which showed high radiocounts bound to SK-SD-coupled particles in the sera of nephrotic patients who had a strong immediate reaction against SK-SD and a severe disease state. 相似文献
75.
A metastable -Pu (bcc) solid solution has been retained to room temperature by rapid quenching of Pu-rich Pu-Ti alloys from the liquid state. Until now, -Pu solid solutions were limited to high temperatures and had not been successfully quenched to room temperature without transformation. The apparatus used to quench the specimens was a modified gun-type splat-cooling unit, capable of producing extremely high cooling rates of from 106 to 108 ° C sec–1. -Pu(Ti) was retained in the composition region from 20 to more than 45 at.% Ti, and extrapolation of the lattice parameter/composition curve yielded a value of a
0 = 3.530 Å for -Pu at 20° C. This modification differs from the -Pu modification derived by extrapolating from high temperature to 20° C by a small valence increase of 0.1. Metastable -Pu (Ti) (fcc) solid solutions were also quenched-in with alloys containing lesser amounts of Ti, and evidence was found to indicate that the was probably a product of -Pu(Ti) solid-state decomposition. 相似文献
76.
Regelous M Turner SP Elliott TR Rostami K Hawkesworth CJ 《Analytical chemistry》2004,76(13):3584-3589
We describe a new method for the chemical separation and analysis of Pa in silicate rock samples by isotope dilution. Our new technique has the following advantages over previous methods: (a) The initial separation of Pa from the rock matrix is carried out using anionic exchange resin and HCl-HF mixtures, avoiding the need to remove F(-) quantitatively from the sample solution prior to this step, (b) Efficient ionization of Pa is achieved using a multicollector inductively coupled plasma mass spectrometer, so that smaller sample sizes and shorter measurement times are required, compared to previous methods using thermal ionization mass spectrometry or alpha spectrometry. (c) Plasma ionization requires less efficient separation of the high field strength elements from Pa, thus reducing reagent volumes, blanks, and sample preparation times. Instrumental mass fractionation can be corrected for using admixed U of known isotopic composition. Using this method, Pa concentrations can be measured to a precision of approximately 0.5% and an accuracy of approximately 1% using only a few tens of femtograms of Pa. 相似文献
77.
Roger W. Elliott Miner P. Marchbanks Michael G. McWilliams Larry J. Ringer D.B. Simmons 《Computers & Industrial Engineering》1978,2(3):141-151
Under certain conditions, traditional hypothesis-testing techniques may be used as a management tool by software developers or software purchasers who wish to insure that their packages have some specified reliability level. These conditions are: (1) the existence of independent collections of test data, (2) a way of determining the correctness of processing of these collections, and (3) a way of randomly selecting test data.Two basic approaches have been described. In a fixed sample size test, the user decides on the reliability desired. He can then determine the number of test cases which must be examined and the acceptance/rejection criteria. In a sequential test, the desired reliability level is again pre-determined, but samples are tested one at a time until an accept/reject decision can be made.Experiments with a large amount of error data derived from six separate systems indicate that reliability results derived from these models are consistent with actual reliability figures.Most current acceptance procedures are based on a naive assumption that a large program can be exhaustively tested and delivered in an error-free condition. Because these expectations cannot be fulfilled, the manager of a software development project or the purchaser of a software product is provided with no quantitative information on which to base an acceptance decision and is thus forced to make these decisions based mostly on intuition and his own experience in similar situations. These models allow one to replace these intuition-based decisions with quantitatively-based decisions and thus constitute an important contribution to the science of management of software development efforts. 相似文献
78.
This paper discusses the general problem of designing building subsystems which include probabilistic demands thus producing a stochastic problem. This class of problem, if linear, can be readily solved using classical stochastic linear programming. It is shown that the problem may be formulated as a stochastic dynamic program. A problem of designing the HVAC subsystem is formulated and solved as a dynamic program. Comparisons are made between the two methods. It is shown that dynamic programming is the more powerful method both in terms of obtaining the solution and in its post-optimality analysis. It is suggested that dynamic programming is a suitable technique for a wide range of building and architectural design problems. 相似文献
79.
80.
J J Doesburg E C Lamprecht M Elliott 《Journal of the science of food and agriculture》1970,21(12):632-635
Fishmeals with different moisture contents, having water activities (aw) ranging from 0.34 to 0.71, were infected with strains of Salmonella oranienburg or S. senftenberg and were stored at 15, 20 and 30°c, packed in nitrogen or air. The initial death rates (calculated over storage periods of 70 days) were not appreciably influenced by reduction of aw from 0.71 to 0.54. Further reduction of aw to 0.34 caused a decrease of the initial death rate, in particular in meals stored at 15 or 20°c. As compared with fishmeals packed in air, meals packed in nitrogen showed a decrease of initial death rates, especially in meals with the lowest aw and stored at 15 and 20°c. Death rates calculated over longer storage periods were smaller than initial death rates, in particular in meals with aw 0.54 stored at 15 and 20°c and meals with aw 0.34 stored at 15, 20 and 30°c. Pelletisation of meals with aw 0.72-0.74 caused a 102-103-fold reduction of initial Salmonella counts. The death rates of salmonellae which survived the pelletisation treatments were of about the same order as found for the initial death rates of salmonellae in non-pelletised meals with about the same aw. 相似文献