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91.
92.
S. Heimbs P. Middendorf S. Kilchert A. F. Johnson M. Maier 《Applied Composite Materials》2007,14(5-6):363-377
The characterisation of the mechanical behaviour of folded core structures for advanced sandwich composites under flatwise
compression load using a virtual testing approach is presented. In this context dynamic compression test simulations with
the explicit solvers PAM-CRASH and LS-DYNA are compared to experimental data of two different folded core structures made
of aramid paper and carbon fibre-reinforced plastic (CFRP). The focus of the investigations is the constitutive modelling
of the cell wall material, the consideration of imperfections and the representation of cell wall buckling, folding or crushing
phenomena. The consistency of the numerical results shows that this can be a promising and efficient approach for the determination
of the effective mechanical properties and a cell geometry optimisation of folded core structures. 相似文献
93.
94.
Meng-Che Wu Jian Guo Liu Philippa Jane Mason 《International journal of remote sensing》2013,34(21):7589-7606
Kriging is a widely used technique for raster data interpolation from point samples, such as in the generation of digital elevation models and geochemical maps. The quality of the result depends on both spatial distribution of the sampled values and nature of the semivariogram model, which fits an empirical global function to the sample data set to predict values at the unknown locations. However, such a semivariogram model may not be suitable for data sets with complex local trends in spatial distribution, such as those observed in differential interferometric synthetic aperture radar (DInSAR) data of the Wenchuan earthquake. Here we propose a modified kriging method, adaptive local kriging (ALK), for the retrieval of data lost through decoherence in Advanced Land Observing Satellite (ALOS) phased array L-band synthetic aperture radar (PALSAR) DInSAR data, within the intensely deformed fault zone of the 2008 Wenchuan earthquake. In ALK, a series of dynamic linear local semivariogram models is used rather than a global semivariogram for the whole data set. The localized adaptive approach ensures accurate interpolation in the areas of good DInSAR data with small decoherence gaps and avoids drastic errors in the extensive decoherence gaps; the overall value prediction is thus significantly improved, as confirmed by comparison with the original DInSAR data and fidelity verification experiments. 相似文献
95.
96.
Hülsheger Ute R.; Lang Jonas W. B.; Maier Günter W. 《Canadian Metallurgical Quarterly》2010,15(4):505
Models of emotional labor suggest that emotional labor leads to strain and affects job performance. Although the link between emotional labor, strain, and performance has been well documented in cross-sectional field studies, not much is known about the causal direction of relationships between emotional labor, strain, and performance. Goal of the present study was therefore to test the direction of effects in a two-wave longitudinal panel study using a sample of 151 trainee teachers. Longitudinal lagged effects were tested using structural equation modeling. Results revealed that the emotional labor strategy of surface acting led to increases in subsequent strain while deep acting led to increases in job performance. In contrast, there was no indication of reverse causation: Neither strain nor job performance had a significant lagged effect on subsequent surface or deep acting. Overall, results support models of emotional labor suggesting that surface and deep acting causally precede individual and organizational well-being. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
97.
Ohne Zusammenfassung 相似文献
98.
Huseyin Sehitoglu Tracy Smith Xinlin Qing Hans J. Maier J. A. Allison 《Metallurgical and Materials Transactions A》2000,31(1):139-151
The stress-strain behavior of cast 319-T6 aluminum-copper alloys with three different secondary dendrite arm spacings (SDASs)
was studied at high temperatures and under thermomechanical deformation, exposing marked cyclic softening. A two state-variable
unified inelastic constitutive model proposed earlier was modified to describe the stress-strain responses of these alloys
by considering the variation of hardening and recovery functions of back-stress and drag stress. The SDAS was incorporated
in the model as a length-scale parameter, and the material constants were determined systematically from experiments on a
cast 319-T6 aluminum with small and large SDASs. The capabilities of the constitutive model were checked by the comparisons
of simulations to experiments in the small-strain regime (<0.005). The results show that the model provides successful simulations
for material response after thermal exposure at high temperature and cyclic transient stress-strain behavior. The causes of
mechanical behaviors at the macro scale are discussed based on microstructural changes during thermal exposure. 相似文献
99.
L. Badano M. Benedikt P. Bryant M. Crescenti P. Holy P. Knaus A. Maier M. Pullia S. Rossi 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》1999,430(2-3)
The treatment of cancer with accelerator beams has a long history with betatrons, linacs, cyclotrons and now synchrotrons being exploited for this purpose. Treatment techniques can be broadly divided into the use of spread-out beams and scanned ‘pencil’ beams. The Bragg-peak behaviour of hadrons makes them ideal candidates for the latter. The combination of precisely focused ‘pencil’ beams with controllable penetration (Bragg peak) and high, radio-biological efficiency (light ions) opens the way to treating the more awkward tumours that are radio-resistant, complex in shape and lodged against critical organs. To accelerate light ions (probably carbon) with pulse-to-pulse energy variation, a synchrotron is the natural choice. The beam scanning system is controlled via an on-line measurement of the particle flux entering the patient and, for this reason, the beam spill must be extended in time (seconds) by a slow-extraction scheme. The quality of the dose intensity profile ultimately depends on the uniformity of the beam spill. This is the greatest challenge for the synchrotron, since slow-extraction schemes are notoriously sensitive. This paper reviews the extraction techniques, describes methods for smoothing the beam spill and outlines the implications for the extraction line and beam delivery system 相似文献
100.
Philippa Howden-Chapman Helen Viggers Ralph Chapman Des ODea Sarah Free Kimberley OSullivan 《Energy Policy》2009,37(9):3387
New Zealand houses are large, often poorly constructed and heated, by OECD standards, and consequently are colder and damper indoors than recommended by the World Health Organisation. This affects both the energy consumption and the health of households. The traditional New Zealand household pattern of only heating one room of the house has been unchanged for decades, although there has been substantial market penetration of unflued gas heaters and more recently heat pumps. This paper describes the residential sector and the results of two community-based trials of housing and heating interventions that have been designed to measure the impact of (1) retrofitting insulation and (2) replacing unflued gas heaters and electric resistance heaters with heat pumps, wood pellet burners and flued gas heaters. The paper describes findings on the rebound effect or ‘take-back’—the extent to which households take the gains from insulation and heating improvements as comfort (higher temperatures) rather than energy savings, and compares energy-saving patterns with those suggested by an earlier study. Findings on these aspects of household space heating are discussed in the context of the New Zealand government's policy drive for a more sustainable energy system, and the implications for climate change policy. 相似文献