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1.
Ride comfort optimization of a city bus is considered in this article, using stiffness and related damping of the power unit
mounts as design variables. The response of the bus, due to road irregularities, is calculated in the time domain by using
a finite element (FE) model describing the complete vehicle. The body of the bus is condensed, using a substructuring technique,
in order to reduce the simulation times. Operational deflection shapes (ODS) have been used to compare measured and calculated
vibrations and some corrections of the FE model have been done. The response, i.e. acceleration, at three locations in the
bus has been frequency-weighted according to the comfort standard ISO 2631:1997. The resulting root mean square (RMS) values
of these responses are then used in the objective functions in the optimization procedure. The computational results show
that it is possible to increase the ride comfort. However, the improvement of the ride comfort is probably too small to have
a substantial subjective impact on the passenger in the bus. The results show that the objective function, regarding the overall
ride comfort in the bus, has local optima.
Received October 10, 1999 相似文献
2.
Interfacial Tension; a Stabilizing Factor for Janus Emulsions of Silicone Bixa Orellana Oils
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Gislaine Ricci Leonardi Silas A. Monteiro e Silva Carina M. Guimarães Fabiana A. Perrechil Richardt G. Landgraf Stig E. Friberg 《Journal of surfactants and detergents》2016,19(5):1009-1014
The destabilization process was investigated for a Janus emulsion of silicone and Bixa Orellana oils stabilized by polyoxyethylene sorbitan monooleate (Tw 80) and carboxymethyl cellulose. The emulsion stabilized with Tw 80 showed significant and fast creaming, a process that was prevented by the addition of the polymer. During the extensive coalescence of the emulsions stabilized by Tw 80, the Janus topology was retained for months of storage until, finally, separation of the oils occurred. This result strongly indicates an unexpected stabilizing action of the i nterfacial free energy. This conclusion was supported by a calculation for a realistic model system of the interfacial energy difference between two cases of coalescence. In the first case, the two coalescing Janus drops united into a larger Janus drop, while in the second case two drops formed, each with only one oil. The first case gave a spontaneous reaction (reduced interfacial energy), while the second one meant an increase of energy, i.e. it cannot happen without adding energy. The authors are aware that this stabilization is a new phenomenon in emulsion science with potential ramifications in future emulsion technology. However, it is essential to realize that the stabilization is of temporary occurrence in the destabilization process, and the free energy to give a final emulsion state with separated oils is overwhelmingly dominant. In short, Janus emulsions will, in the end, separate into layers of the liquids, like all emulsions. 相似文献
3.
An error indicator for the generalized eigenvalue problem using the hierarchical finite element method 总被引:1,自引:0,他引:1
The hierarchical concept applied to eigenvalue problems is considered. An error indicator is derived from the pertinent Rayleigh quotient. The indicator serves as an estimation ‘a posteriori’ of the relative change in an eigenvalue for a hierarchical refinement. A numerical example is included. 相似文献
4.
Stig E. Friberg 《加拿大化工杂志》2007,85(5):602-608
The evaporation path was determined for the emulsion system water, linalool and 5% Laureth 4, (L4), from the phase diagram of the components. The initial part of the evaporation took place in a two‐phase region of the emulsion and the path, expressed as fractions of the compounds, was non‐linear reflecting the changed vapour pressure of the linalool. The latter part of the evaporation, on the other hand, occurred through a three‐phase region and the path now formed a straight line. The recently introduced algebraic approach to extracting information from phase diagrams enabled presenting quantitative changes in composition, phase fractions and total content of the emulsion, as well as the vapour pressure versus different variables; including time. 相似文献
5.
Friberg SE Szymula M Fei L Barber J Al-Bawab A Aikens PA 《International journal of cosmetic science》1997,19(6):259-270
The phase diagram water, phenethyl alcohol and laureth 4 was determined and the variation of the vapour pressure of the alcohol was determined during evaporation using gas chromatographic head-space analysis. The phase changes during evaporation were estimated from the phase diagram and compared to the appearance of the emulsion using optical microscopy. The transfer of the fragrance ingredient between different phases during the process was estimated and its measured vapour pressures compared to those calculated from values of earlier determination in different phases in the system. The agreement was good. 相似文献
6.
Nonparaxial eigenmodes of stable resonators 总被引:5,自引:0,他引:5
A method to determine the nonparaxial eigenmodes of stable resonators is presented. The method is based on the perturbation theory of Lax et al. For calculating nonparaxial components of the electric field. A matrix formalism which uses a mode expansion into paraxial Hermite-Gaussian modes is applied to describe the nonparaxial propagation and the phase shift at a parabolic and a spherical mirror. Expressions for these matrices are derived analytically. Multiplying all matrices corresponding to a round trip, a matrix for the resonator is obtained. Eigenmodes of the resonator are numerically found by solving the eigenvalue problem. In the special case of paraxial propagation and parabolic mirror profiles, the standard Hermite-Gaussian modes result analytically. Nonparaxial modes of a given resonator are compared for different mirror profiles. It is found that, in the nonparaxial domain, spherical mirrors do not change the mode profile and the frequencies of the transverse modes, in contrast to parabolic mirrors which aberrate the beam profile and cause frequency shifts 相似文献
7.
U L?nn S L?nn S Friberg B Nilsson C Silfversw?rd B Stenkvist 《Canadian Metallurgical Quarterly》1995,1(10):1189-1194
Amplification of c-erb-B2 is examined in patients with transitional cell bladder carcinoma. In a pilot study we found that the amplification correlated with high tumor grade. Tumor grade is a known prognostic factor. Therefore, we next examined the prognostic value of c-erb-B2 amplification in patients with >16 years of clinical follow-up. The gene copy number was determined, using semiquantitative PCR, in archival formalin-fixed tissues. Twenty-three percent (37/163 patients) showed the amplification. The amplification correlated with grade and stage. Moreover, we found that tumor grade (P < 0.001) and c-erb-B2 amplification (P < 0.001) showed prognostic information for survival. Patients with grade 3 tumors and concomitant c-erb-B2 amplification showed the worst prognosis. Multivariate analysis indicates that grade and c-erb-B2 amplification are independent prognostic factors. 相似文献
8.
A semiconductor saturable absorber modulator is used, for the first time, in a passively Q-switched microchip laser in transmitting mode. The laser has a wavelength of 1.55 μm in a single longitudinal TEM00 mode beam and has pulse characteristics that compare favourably with previously reported data on comparable devices 相似文献
9.
To identify the level of compliance with the new radiation protection regulation among Norwegian health care enterprises (HCEs). Totally, 41 HCEs were authorised to use advanced X-ray equipment for medical purposes during 2005-07. Follow-up inspections with 14 HCEs were carried out during 2007-09. Main topics for the inspections were those requirements identified as most challenging to implement in the authorisation process. Totally, 192 non-conformities with the regulation were revealed during the authorisation process. The inspections revealed that 93 % of the inspected HCEs had non-conformities with the regulation. Most common non-conformities dealt with skills in radiation protection, establishment of local diagnostic reference levels, access to medical physicists and performance of quality control of X-ray equipment. Inspections are an effective tool for implementation of regulation the requirements at the HCEs, thus improving radiation protection awareness. 相似文献
10.
Rong Guo Thomas Moffett Jr. Mary E. Compo Stig E. Friberg Marcel Benton Raymond Wong 《Journal of the American Oil Chemists' Society》1996,73(1):15-19
Addition of n-decanol at appropriate concentrations is beneficial to increasing the solubilization amount of water in a water-in-oil
microemulsion in the system of nonylphenol ethoxylate/olive oil/water, but it destabilized the lamellar liquid crystal and
reduced the solubilization of olive oil in the lamellar liquid crystal. 相似文献