Boundary element analysis of a plate on elastic foundations

The objective of this study is to examine the applicability of the boundary element method to analysing a plate on elastic foundation. The fundamental solution of the problem is presented as a Fourier-Bessel integral. For the computation of the values of the fundamental solution an algorithm was developed in which the Fourier-Bessel integral was decomposed into an alternative convergent sequence. Equations based on the direct and indirect boundary element method were derived for a plate situated on a one- or two-parametric elastic foundation. According to the theory presented, computer programs based on the direct and indirect boundary element method were developed. These programs can be used for examining the behaviour of a smooth-boundary plate on a one- or two-parametric elastic foundation. The computer programs were tested by several examples. The results obtained by using a small number of boundary elements compared favourably to the results obtained by a fine finite element mesh. The study shows that the boundary element method is applicable to the analysis of a plate on elastic foundation.     

ASYMPTOTIC PROPERTIES OF SOME PRELIMINARY ESTIMATORS FOR AUTOREGRESSIVE MOVING AVERAGE TIME SERIES MODELS

Abstract. Some simple preliminary estimators for the coefficients of mixed autoregressive moving average time series models are considered. As the first step the estimators require the fitting of a long autoregression to the data. The first two methods of the paper are non-iterative and generally inefficient. The estimators are Yule-Walker type modifications of the least squares estimators of the coefficients in auxiliary linear regression models derived, respectively, for the coefficients of the long autoregression and for the coefficients of the corresponding long moving average approximation of the model. Both of these estimators are shown to be strongly consistent and their asymptotic distributions are derived. The asymptotic distributions are used in studying the loss in efficiency and in constructing the third estimator of the paper which is an asymptotically efficient two-step estimator. A numerical illustration of the third estimator with real data is given.     

Studies on Helium Liquids by Vibrating Wires and Quartz Tuning Forks

We present results of low-temperature experiments on dilute mixtures of ³He in ⁴He and on pure ³He, obtained by means of two kinds of mechanical oscillators immersed in the liquid sample: vibrating wires and quartz tuning forks. The helium sample was cooled either by adiabatic demagnetization of an immersed copper nuclear stage or by adiabatic melting of ⁴He in superfluid ³He. The measured effect of the surrounding fluid on the mechanical resonance of the oscillators is compared with existing theories. We also discuss resonances of second sound and the state of supersaturation, both observed by a tuning fork in helium mixtures.     

Dynamic mechanical properties and morphology of polypropylene/maleated polypropylene blends

The dynamic mechanical properties of both homopolypropylene (PPVC)/Maleated Poly-propylene (PP-g-MA) and ethylene-propylene block copolymer (PPSC)/Maleated Poly-propylene (PP-g-MA) blends have been studied by using a dynamic mechanical thermal analyzer (PL-DMTA MKII) over a wide temperature range, covering a frequency zone from 0.3 to 30 Hz. With increasing content of PP-g-MA, α relaxation of both blends gradually shift to a lower temperature and the apparent activation energy ΔE_α increases. In PPVC/PP-g-MA blends, β relaxation shifts to a higher temperature as the content of PP-g-MA increases from 0 to 20 wt % and then change unobviously for further varying content of PP-g-MA from 20 to 35 wt %. On the contrary, in the PPSC/PP-g-MA blends β₁ relaxation, the apparent activation energy ΔE_β1 and β₂ relaxation are almost unchanged with blend composition, while ΔE_β2 increases with an increase of PP-g-MA content. In the composition range studied, storage modulus É value for PPSC/PP-g-MA blends decreases progressively between β₂ and α relaxation with increasing temperature, but in the region the increment for PPVC/PP-g-MA blends is independent of temperature. The flexural properties of PPVC/PP-g-MA blend show more obvious improvement on PP than one of PPSC/PP-g-MA blends. Scanning electron micrographs of fracture surfaces of the blends clearly demonstrate two-phase morphology, viz. the discrete particles homogeneously disperse in the continous phase, the main difference in the morphology between both blends is that the interaction between the particles and the continuous phase is stronger for for PPVC/PP-g-MA than for PPSC/PP-g-MA blend. By the correlation of the morphology with dynamic and mechanical properties of the blends, the variation of the relaxation behavior and mechanical properties with the componenet structure, blend composition, vibration frequency, and as well as the features observed in these variation are reasonably interpreted. © 1996 John Wiley & Sons, Inc.     

多层帘式涂布和一种新型压光技术

帘式涂布是一种低冲击预计量涂布方式,可用于纸和纸板的涂布、帘式涂布技术所产生的涂层为仿形涂层,因而能提供良好的纤维覆盖。在多层帘式涂布中,可以同时进行多层涂布。与单层帘式涂布相比,多层帘式涂布具有许多优点：投资成本更低、设计不同涂层性质更具灵活性、具有更大的涂布操作空间及涂层更薄等,     

Cardiac status and cardiovascular risk factors among Finnish sea pilots

The present study investigated the expressed number of CR1 on erythrocytes (E) in relationship of the CR1 density genotype from 46 patients with systemic lupus erythematosus (SLE) and 47 healthy volunteers. The CR1 genotype was determined by a method based on polymerase chain reaction (PCR) amplification of the genomic DNA fragment of 1.8 kb separated by HindIII endonuclease digestion and agarose gel electrophoresis. Our data supported the earlier results that the number of binding sites/E for monoclonal anti-CR1 decreased among SLE patients compared with normal individuals having the same alleles for the CR1/E density. At the same time the novelty of our recent results was that the decreased expression of CR1 on E correlated significantly with kidney involvement in patients homozygous for the CR1/E high density allele (HH). These data suggest that the deficiency of the detectable number of CR1 on erythrocytes is acquired in this SLE population.     

Reliability Growth and Duane Learning Curves

This paper examines Duane learning curves for reliability improvement between successive reliability tests. A constant failure rate ratio between successive tests gives curved lines on a Duane plot. Gordon's observation that dominant failures appear exponentially with test time leads to exponential failure rate ratio models. These models, although not the only possible ones, give results that agree well with observations from practice.     

Multilinear model for spatial pattern analysis of the Measurement of Haze and Visual Effects project

A multilinear model was developed for the analysis of the spatial patterns and possible sources affecting haze and its visual effects in the southwestern United States. The data from the project Measurement of Haze and Visual Effects (MOHAVE) collected during the late winter and mid-summer of 1992 at the monitoring sites in four states (i.e., California, Arizona, Nevada and Utah) were used in the study. The three-way data array was analyzed by a four-product-term model. This study makes a direct effort to include wind patterns as a component in the model in order to obtain the information of the spatial patterns of source contributions. The solution is computed using the conjugate gradient algorithm with applied non-negativity constraints. For the winter data set, reasonable solutions contained six sources and six wind patterns. The analysis of summer data required seven sources and seven wind patterns. The ME results are compared to the prior single-species empirical orthogonal function analysis results--and prior work describing the transport pathways.     

Analysis of wines for metals using atomic-absorption spectrophotometry

Summary Ca, Cd, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Pb and Zn were determined using Atomic-Absorption Spectrophotometry (AAS) in 59 Finnish (n =10) and foreign (n = 49) wines sold in Finland. Cd and Pb were determined in a graphite furnace and the other metals with an air-acetylene flame. All wines contained only low levels of heavy metals; in all cases the concentration of Pb was under 0.3 mg/1, that of Cu was under 1.0 mg/1, that of Zn was under 5.0 mg/1 and that of Cd was under 0.1 mg/l, which are the maximum levels permitted in some countries. Finnish wines contained less Pb and Mg and more Cr and Na than the foreign wines analysed.

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Die Analyse von Weinen auf Metalle mittels Atomabsorptionsspektrophotometrie

Zusammenfassung Ca, Cd, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Pb und Zn wurden unter Anwendung der Atomabsorptionsspektrophotometrie (AAS) in 59 finnischen (n =10) und ausländischen (n = 49) in Finnland zum Verkauf gelangenden Weinen analysiert. Die Bestimmung von Cd und Pb wurde im Graphitofen, die der übrigen in einer Luft-Acetylenflamme vorgenommen. Alle untersuchten Weine enthielten nur geringe Mengen von Schwermetallen; in allen Fällen blieb die Pb-Konzentration unter 0,3 mg/l, die Cu-Konzentrationunter 1,0 mg/1, die Zn-Konzentration unter 5,0 mg/1 und die Cd-Konzentration unter 0,1 mg/1. Die angegebenen Konzentrationen stellen die in einigen Ländern zugelassenen Höchstwerte dar. Die finnischen Weine enthielten weniger Pb und Mg, aber mehr Cr und Na als die zur Untersuchung gelangten ausländischen Weine.

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Paper presented at the 27th IUPAC Congress, 27–31 August, 1979, Helsinki