1,010 research outputs found
Thermal Dissipation Performance of a Heat Sink/Vapor Chamber Prepared by Metal Injection Molding Process
No full textFlow behavior of aluminum-based materials at ultrahigh temperatures in the presence of a liquid phase
No full textExperiments were conducted to determine the flow behavior of three materials at ultrahigh temperatures: an Al-6061 composite containing 20 vol% SiC whiskers and unreinforced Al-6061 and Al-1050 alloys prepared by casting. Tensile tests were performed at strain rates up to 5× 10-1 s-1 and over a range of ultrahigh temperatures up to and above the temperatures where there is a small amount of liquid phase. High strain rate superplasticity was achieved in the composite material but not in the unreinforced alloys. For all three materials, it is shown that the true activation energy for flow changes from values of <200 kJ mol-1 at the lower temperatures where there is no liquid phase to exceptionally high values in the presence of a liquid phase: these values are up to >1000 kJ mol-1 for the composite and the Al-1050 alloy. It is concluded that exceptionally high activation energies are an inherent feature of flow in materials containing a small amount of discontinuous liquid at temperatures immediately above the onset of partial melting. <br/
On the activation energies observed in Al-based materials deformed at ultrahigh temperatures
No full textThis study examines the exceptionally high activation energies estimated fi om data obtained from various composites exhibiting high strain rate superplasticity and loaded at ultrahigh temperatures near or slightly above the solidus. It is shown that the activation energies for the 6061 composite and for Al 6061 and 1050 alloys are below 200 kJ/mol at temperatures lower than the incipient melting temperature, T-i, but they become significantly higher at temperatures near or slightly above T-i and this increase is independent of the alloy system, the grain size, whether the material is superplastic and the dominant deformation mechanism at T<T-i. There is a transition from plastic flow in a solid state to a viscous-like flow behavior in the Al-6061 systems at T>610 degreesC and in the Al-1050 alloy at T>650 degreesC. It is concluded that the high values of Q(t) have no physical meaning in terms of the rate-controlling diffusive species
Oral administration of milk from cows immunized with human intestinal bacteria leads to significant improvements of symptoms and signs in patients with oral submucous fibrosis.
No full textCorrection to : Cost-Effectiveness of Parent–Child Interaction Therapy in Clinics versus Homes : Client, Provider, Administrator, and Overall Perspectives (Journal of Child and Family Studies, (2018), 27, 10, (3329-3344), 10.1007/s10826-018-1159-4)
No full textThe original version of this article unfortunately contained a mistake. The Author contributions section currently states: “A.F.: designed and conducted data analyses for this study, supervised by B.Y. with input by T.F. A.F. and T.F. assisted B.Y. in writing and revising the manuscript.” In fact, B.Y. and T.F. assisted A.F. in writing and revising the manuscript. Although T.F. and B.Y. were both involved in the writing, primary credit should go to A.F. (Alexis French, the first author). The authorship order above is accurate.</p
Natural attenuation of high concentrations of organic pollutants by biodegradation in soils
No full textIn view of its relatively low cost, monitored natural attenuation by biodegradation is increasingly relied upon to clean up pollution of soils caused by landfills, industrial activities and major transport and storage related spills. Current policy tends to aim at reducing soil pollution to levels reflecting tolerable risk for specific recipients within a reasonable time frame. Natural attenuation by biodegradation of high concentrations of major pollutants that preferentially partition to the particle fraction of soils tends to be poor. These pollutants include hazardous hydrocarbons, highly halogenated hydrocarbons and nitro-organics. Relying on natural attenuation of these compounds, when feasible at all, leads to exceeding tolerable risk levels for a long time. Better perspectives exist for natural attenuation by biodegradation of pollutants that partition to a significant extent to the aqueous phase, especially for low molecular weight organic aromatics and chlorinated solvents. Dependent on conditions in the aquifer and the presence of suitable micro-organisms, there can be substantial biodegradation of a variety of hydrocarbons, organochlorines and oxygenates. In some cases natural attenuation has been found to bring down high levels of pollution to levels meeting current standards of tolerable risk. Predictions whether in the future levels reflecting tolerable risk can be attained, are uncertain. Uncertainty is especially large in case of expanding plumes. There are uncertainties that beset current modelling to predict future concentrations and there is uncertainty about what in the future will be considered tolerable risk. Even when it is supposed that current standards will be applied indefinitely, uncertainties related to present modelling and sampling often prevent certainty that these standards will be met in the future. In practice, natural attenuation is often falling short of attaining promised outcomes. This means that often interventions aimed at enhanced remediation will be necessary to achieve tolerable risk within a reasonable time frame. These may include enhanced biodegradation
Further refinement of self-normalized Cramér-type moderate deviations
Get PDFIn this paper, we study the self-normalized Cramér-type moderate deviations for centered independent random variables X1,X2,... with 0 <E | Xi | 3< ∞. The main results refine Theorems 1.1 and 1.2 of Wang [Q. Wang, J. Theoret. Probab. 24 (2011) 307–329], the Berry−Esseen bound (2.11) and Corollaries 2.2 and 2.3 of Jing, et al. [B.Y. Jing, Q.M. Shao and Q. Wang, Ann. Probab. 31 (2003) 2167–2215] under stronger moment conditions
A THEOREM ON COMMON FIXED POINTS OF EXPANSION TYPE MAPPINGS IN CONE METRIC SPACES
No full textIn this paper, we present a common fixed point theorem for expansion type mappings in complete cone metric spaces. This result generalizes and extends the theorem of S.Z. Wang, B.Y. Li and Z.M. Gao and K. Iseki [8, Theorem 4] for a pair of mappings to cone metric spaces
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