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31.
A mediation service for monitoring terms of service can facilitate collaboration in virtual organizations (VO) by ensuring secure, private access to service resources. The author envisions a VO requiring a mediation service for monitoring and enforcing terms and conditions as well as a QoS-monitoring service. One or more trusted third parties (TTPs) could provide these two services. Indeed, legal regulatory requirements might explicitly state that third parties must provide such services. 相似文献
32.
The response of Nomex sheets to some penetrants has been analyzed. The process of moisture uptake depends on the relative
humidity (RH) of the ambient atmosphere and the initial characteristics of the polymer. In the case of common laboratory solvents,the uptake by the polymer shows an inverse dependence on the molar volume of the former. Although the calendered and the uncalendered
Nomex sheets exhibit an overall similarity in their response to various penetrants,quantitative comparison reveals distinct differences. 相似文献
33.
Synthesis of Hg(Tl)Ba
2
Ca
2
Cu
3
O
8+δ
superconducting tapes have been accomplished by annealing the precursor tape, Ba
2
Ca
2
Cu
3
O
y
(fabricated by doctor blade tape casting technique) in an environment of Hg(Tl) vapour. Characterization of superconducting
HTSC tape sample was carried out through XRD, TEM, SEM and R-T measurements. Surface morphological investigations of the as-synthesized
Hg(Tl)Ba
2
Ca
2
Cu
3
O
8+δ
HTSC tapes by scanning electron microscope have shown the occurrence of curious growth characteristics resembling spiral like
features. These growth spirals encompass nearly the whole grain suggesting that spiral growth led to the formation of small
crystal like grains of superconducting material Hg(Tl)Ba
2
Ca
2
Cu
2
O
8+δ
.The likely mechanism for the generation of these screw dislocations has been elucidated in terms of incoherent coalescence
of growth fronts formed from Hg(Tl):1223 and Hg(Tl):1234 nuclei. 相似文献
34.
The residual effects of cumulative thermal aging on the crystal structural characteristics of the fluoro carbon poly(tetra fluoro ethylene) (PTFE) have been studied by X‐ray diffraction methods. The initial hexagonal arrangement of the PTFE chains in a 157 helical conformation is left unaffected by the exposures to temperatures (T), up to and beyond its melting point, Tm. The unit cell registers a residual anisotropic volume expansion. The anisotropy arises from the enhanced enlargement of the basal plane dimension a compared with the axial dimension c. Conformational changes contributing to the observed increase in the chain length have been examined. Enhancement of residual crystallinity of samples aged at T's < Tm suggests that the selective thermal aging could be used as an effective tool to improve the initial crystallinity of commercially available PTFE. The activation energy for 50% enhancement in initial crystallinity has been estimated as 53.9 kJ mol?1. Aging at 400°C, a temperature above Tm, is accompanied by markedly different features viz., deterioration in crystallinity and other structural characteristics. The overall behavior of thermally aged PTFE bears a marked similarity to many polyamides. POLYM. ENG. SCI., 47:1724–1729, 2007. © 2007 Society of Plastics Engineers 相似文献
35.
Iron crosslinked carboxy methyl cellulose (CMC) nanoparticles prepared by the process of emulsion crosslinking were studied for the removal of arsenic(V) ions from aqueous solution. Batch and column studies were conducted in order to investigate the efficiency of nanoparticles towards arsenic remediation. The Langmuir and Freundlich equations were applied to describe the biosorption isotherm. The results obtained from fixed bed studies showed that the column demonstrates fairly well at lowest flow rate and also, bed exhaustion time was found to increase with increasing bed height. The bed depth service time (BDST) model was used to analyze the experimental data and the model parameters were evaluated. Antibacterial studies were also conducted which confirms that Fe-CMC nanoparticles are efficient towards the removal of bacteriological contamination also. 相似文献
36.
Sumesh George Prabhakaran S. Anjana Mailadil T. Sebastian Jerzy Krupka Sreekumar Uma Jacob Philip 《International Journal of Applied Ceramic Technology》2010,7(4):461-474
A new low-permittivity polymer–ceramic composite for packaging applications has been developed. The ceramic-reinforced polyethylene and polystyrene composites were prepared by melt mixing and hot molding techniques. Low-loss, low-permittivity Li2MgSiO4 (LMS) ceramics prepared by the solid-state ceramic route were used as the filler to improve the dielectric properties of the composites. The relative permittivity and dielectric loss were increased with the increase in the ceramic loading at radio and microwave frequencies. The mechanical properties and thermal conductivity of the Li2MgSiO4-reinforced polymer–ceramic composite were also investigated. The stability of the relative permittivity of polymer–ceramic composites with temperature and frequency was investigated. The experimentally observed relative permittivity, thermal expansion, and thermal conductivity were compared with theoretical models. 相似文献
37.
Manish Shrivastava Ashok Gidwani Heejung S. Jung 《Aerosol science and technology》2013,47(12):1218-1229
This work examines the measurement of surface specific soot oxidation rates with the High Temperature Oxidation-Tandem Differential Mobility Analyzer (HTO-TDMA) method. The Computational Fluid Dynamics package CFD-ACE+ is used to understand particle flow, oxidation and size dependent particle losses in the laminar aerosol flow reactor using an Eulerian-Lagrangian framework. Decrease of DMA selected mono-disperse particle size distribution due to oxidation within the aerosol tube is modeled using fitted kinetic soot oxidation parameters. The effects of Brownian diffusion and thermophoresis on particle flow and loss to the reactor walls are evaluated. The position of peak particle diameter, which is used as an indicator to determine oxidation rate, is found to be independent of diffusion, thermophoresis and secondary flow effects, thus validating its use in deriving kinetic soot oxidation parameters. Diffusion does not affect the evolution of particle size distribution within the reactor. However, thermophoresis is found to be the dominant mechanism influencing both shape of particle size distribution and particle loss to the walls of the aerosol reactor. Simulations show reduced effects of secondary recirculating flows on the particle flow trajectories in a vertical furnace as compared to horizontal furnace orientation. This work highlights the importance of making accurate measurements of temperature within the modeling domain. Since gas temperature within the flow tube could not be measured with high radial resolution using radiation shielded thermocouple, the derived soot oxidation rate may be uncertain by a factor of 2. Importantly, CFD simulations suggest that a distribution of temperature and size-dependent particle reactivities may be present in the reactor, requiring further theoretical and experimental investigation. 相似文献
38.
Ford Julian D.; Racusin Robert; Daviss William B.; Ellis Cynthia G.; Thomas Julie; Rogers Karen; Reiser Jessica; Schiffman Jill; Sengupta Anjana 《Canadian Metallurgical Quarterly》1999,67(5):786
Consecutive admissions to an outpatient child psychiatry clinic diagnosed with oppositional defiant disorder (ODD), attention deficit-hyperactivity disorder (ADHD), or adjustment disorder were assessed for trauma exposure by a structured clinical interview and parent report. Controlling for age, gender, severity of internalizing behavior problems, social competence, family psychopathology, and parent–child relationship quality (assessed by parent report), an ODD diagnosis, with or without comorbid ADHD, was associated with increased likelihood of prior victimization (but not nonvictimization) trauma. ADHD alone was not associated with an increased likelihood of a history of trauma exposure Traumatic victimization contributed uniquely to the prediction of ODD but not ADHD diagnoses. Children in psychiatric treatment who are diagnosed with ODD, but not those diagnosed solely with ADHD, may particularly require evaluation and care for posttraumatic sequelae. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
39.
This paper presents the analysis of a two-unit warm standby system assuming a bivariate exponential density for the joint distribution of failure and repair times of the units. Investigations regarding the stochastic behaviour and important reliability characteristics of the system have been made and earlier results have been verified as particular cases. A few graphs have also been provided to support the theoretical results. 相似文献
40.