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211.
Three-dimensional hydrodynamic analysis of a journal bearing with a two-component surface layer 总被引:1,自引:0,他引:1
Jaros
aw Sep 《Tribology International》2005,38(2):97-104
The article presents a three-dimensional hydrodynamic analysis of a bearing with a two-component surface layer journal. This kind of bearing is characterized by an experimentally proved susceptibility to oil contaminants which is five times lower than that of a typical bearing. The oil flow was described with the Navier–Stokes and energy equations. The equation system was solved by the finite element method. The distributions of pressure, temperature and oil flow velocity were determined. The computation results made it clear that a journal with a two-component surface layer causes a reduction in the bearing load capacity for high eccentricity ratio values (0.7–0.9). Besides, contrary to a typical bearing, considerable velocity changes in oil flow in all directions (circumferential, radial and axial) were observed in the bearing under consideration. Particularly great velocity changes occurred in the radial direction. However, no essential changes were found in the temperature of the oil film and in the attitude angle. 相似文献
212.
Piotr Zawadzki Zbigniew Puchała Jarosław Adam Miszczak 《Quantum Information Processing》2013,12(1):569-576
In this paper we propose an extended version of the ping–pong protocol and study its security. The proposed protocol incorporates the usage of mutually unbiased bases in the control mode. We show that, by increasing the number of bases, it is possible to improve the security of this protocol. We also provide the upper bounds on eavesdropping average non-detection probability and propose a control mode modification that increases the attack detection probability. 相似文献
213.
Dwiecki K Siger A Czubiński J Nogala-Kałucka M Lampart-Szczapa E 《Journal of the American Oil Chemists' Society》2012,89(3):379-387
The focus of the present research was to study inhibition of lipoxygenase activity by rapeseed native polyphenols and the
interactions between those compounds and the enzyme. The enzyme and polyphenolic compounds (polyphenols, phenolic acids) were
extracted from rapeseed (Brassica napus) varieties Aviso and PR45DO3. The total phenolic compounds concentration in tested rapeseed was 1,485–1,691 mg/100 g d.m. (dry matter) and the free phenolic
acids content in both rapeseed varieties was about 76 μg/100 g d.m. The isolated proteins showed lipoxygenase activity. Prooxidant
properties of phenolic compounds in the presence of lipoxygenase and linoleic acid were observed rather in the case of extracts
containing a relatively high concentration of miscellaneous polyphenols. Antioxidant properties were recorded in the case
of phenolic acid extracts which contain only 1.4–1.9% of phenolics present in raw phenolic extracts. We propose that the prooxidant
effect of phenolic compounds comes from quinone and oxidized polyphenols formation. The observed antioxidant activity of phenolic
acid extracts is probably due to their ability to scavenge free radicals formed from linoleic acid. However, reduction of
lipoxygenase ferric to ferrous ions, which prevent the activation of the enzyme and inhibited its activity, was also observed. 相似文献
214.
Maciej Pietrzyk Roman Kuziak Valeriy Pidvysots’kyy Jarosław Nowak Stanisław Węglarczyk Krzysztof Drozdowski 《Metallurgical and Materials Transactions A》2013,44(7):3281-3302
Two copper-based alloys were considered, Cu-1 pct Cr and Cu-0.7 pct Cr-1 pct Si-2 pct Ni. The thermal, electrical, and mechanical properties of these alloys are given in the paper and compared to pure copper and steel. The role of aging and precipitation kinetics in hardening of the alloys is discussed based upon the developed model. Results of plastometric tests performed at various temperatures and various strain rates are presented. The effect of the initial microstructure on the flow stress was investigated. Rheologic models for the alloys were developed. A finite element (FE) model based on the Norton–Hoff visco-plastic flow rule was applied to the simulation of forging of the alloys. Analysis of the die wear for various processes of hot and cold forging is presented as well. A microstructure evolution model was implemented into the FE code, and the microstructure and mechanical properties of final products were predicted. Various variants of the manufacturing cycles were considered. These include different preheating schedules, hot forging, cold forging, and aging. All variants were simulated using the FE method and loads, die filling, tool wear, and mechanical properties of products were predicted. Three variants giving the best combination of forging parameters were selected and industrial trials were performed. The best manufacturing technology for the copper-based alloys is proposed. 相似文献
215.
Monika Trojanowska‐Tomczak Ryszard Steller Jarosław Janukiewicz Jan Ziaja Grzegorz Szafran 《应用聚合物科学杂志》2013,129(6):3536-3545
This work presents composite materials with interpenetrating network structure based on thermoplastic polymer and low melting metal alloy. Composites with various alloy content were prepared by PVC powder sintering to obtain polymer matrix with open pores. Then, liquid Wood's metal was intruded into the matrix using a pressure autoclave. Obtained composites have been studied with respect to microstructure, mechanical, thermal, and electrical properties. SEM micrographs revealed good dispersion of metal in the matrix but at low loading levels it is incomplete. Addition of metal improved mechanical properties, especially flexural strength. Electrical resistivity of samples varies from 10?4 to 10?5 Ω m and these values are typical of conductors. The measurements of electromagnetic interference shielding effectiveness (EMI SE) shows that generally PVC/Wood's metal composites have a good ability to shield electromagnetic waves. Composites containing more than 15 vol % Wood's metal exhibited EMI SE above 40 dB in the major part of frequency range. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献
216.
217.
G Wormser RA Ong G Abrams D Amidei AR Baden T Barklow AM Boyarski J Boyer PR Burchat DL Burke F Butler JM Dorfan GJ Feldman G Gidal L Gladney MS Gold G Goldhaber L Golding J Haggerty G Hanson K Hayes D Herrup RJ Hollebeek WR Innes JA Jaros I Juricic JA Kadyk D Karlen SR Klein AJ Lankford RR Larsen BW LeClaire M Levi NS Lockyer V Lüth C Matteuzzi ME Nelson B Richter K Riles PC Rowson T Schaad H Schellman WB Schmidke PD Sheldon GH Trilling de la Vaissiere C DR Wood JM Yelton 《Canadian Metallurgical Quarterly》1988,38(3):1001-1003
218.
219.
H. Rohm Martina Strobl Doris Jaros 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1997,205(2):108-110
Two butter samples of significantly different yellowness were subjected to cone penetration experiments to measure their
apparent yield value, as an instrumental measure of spreadability, at different temperatures. A ten-member panel evaluated
sensory spreadability of selected pairs of samples, adjusted to particular apparent yield values, by means of simple difference
tests both in the daylight and in a dark-room under red light. The results imply that sensory perception of spreadability
is heavily affected by butter colour. Whereas the results of the dark-room experiments were in line with instrumental measures,
the more yellowish butter was selected as the “easier-to spread” sample when colour differences were perceptible by the panellists.
Received: 26 November 1996 相似文献
220.
ABSTRACTStudying information diffusion and the spread of goods in the real world and in many digital services can be extremely difficult since information about the information flows is challenging to accurately track. How information spreads has commonly been analysed from the perspective of homophily, social influence, and initial seed selection. However, in virtual worlds and virtual economies, the movements of information and goods can be precisely tracked. Therefore, these environments create laboratories for the accurate study of information diffusion characteristics that have been difficult to study in prior research. In this paper, we study how content visibility as well as sender and receiver characteristics, the relationship between them, and the types of multilayer social network layers affect content absorption and diffusion in virtual world. The results show that prior visibility of distributed content is the strongest predictor of content adoption and its further spread across networks. Among other analysed factors, the mechanics of diffusion, content quality, and content adoption by users’ neighbours on the social activity layer had very strong influences on the adoption of new content. 相似文献