967 resultados para CFRP aging composite thermal
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This bimonthly electronic newsletter will provide information and resources on nutrition and health promotion and disease prevention. The Healthy Aging Update is produced for informal and educational purposes only. The newsletter will be distributed electronically and posted on the Department’s website at www.state.ia.us/elderaffairs.
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Report on Aging Resources of Central Iowa for the period July 1, 2005 through June 30, 2009
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This bimonthly electronic newsletter will provide information and resources on nutrition and health promotion and disease prevention. The Healthy Aging Update is produced for informal and educational purposes only. The newsletter will be distributed electronically and posted on the Department’s website at www.state.ia.us/elderaffairs.
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Report on the Iowa Department on Aging for the year ended June 30, 2009
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The State Long-Term Care Ombudsman program operates as a unit within the Iowa Department on Aging. Duties of all long-term care ombudsmen are mandated by the Older Americans Act. This office serves people living in nursing facilities, skilled nursing facilities, residential care facilities, nursing facilities in hospitals, elder group homes and assisted living programs. In order to carry out all of the mandates of the Older Americans Act this office recommends to increase the number of local long-term care ombudsman, develop a volunteer long-term care ombudsman program, clarify the definition of assisted living in Iowa, expand the long-term care ombudsman program into home and community based services, and reinstate the Iowa Office of Substitute Decision Maker.
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The cytoskeleton (CSK) is a nonequilibrium polymer network that uses hydrolyzable sources of free energy such as adenosine triphosphate (ATP) to remodel its internal structure. As in inert nonequilibrium soft materials, CSK remodeling has been associated with structural rearrangements driven by energy-activated processes. We carry out particle tracking and traction microscopy measurements of alveolar epithelial cells at various temperatures and ATP concentrations. We provide the first experimental evidence that the remodeling dynamics of the CSK is driven by structural rearrangements over free-energy barriers induced by thermally activated forces mediated by ATP. The measured activation energy of these forces is ~40kBTr (kB being the Boltzmann constant and Tr being the room temperature). Our experiments provide clues to understand the analogy between the dynamics of the living CSK and that of inert nonequilibrium soft materials.
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Thermal analysis, powder diffraction, and Raman scattering as a function of the temperature were carried out on K2BeF4. Moreover, the crystal structure was determined at 293 K from powder diffraction. The compound shows a transition from Pna21 to Pnam space group at 921 K with a transition enthalpy of 5 kJ/mol. The transition is assumed to be first order because the compound shows metastability. Structurally and spectroscopically the transition is similar to those observed in (NH4)2SO4, which suggests that the low-temperature phase is ferroelectric. In order to confirm it, the spontaneous polarization has been computed using an ionic model.
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Selostus: Kaseiinien yhdistelmägenotyyppien ja [beta]-laktoglobuliinin genotyyppien vaikutus maidon juoksettumisominaisuuksiin ja koostumukseen
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The postsynaptic density protein PSD-95 is a major element of synapses. PSD-95 is involved in aging, Alzheimer's disease (AD) and numerous psychiatric disorders. However, contradictory data about PSD-95 expression in aging and AD have been reported. Indeed in AD versus control brains PSD-95 varies according to regions, increasing in the frontal cortex, at least in a primary stage, and decreasing in the temporal cortex. In contrast, in transgenic mouse models of aging and AD PSD-95 expression is decreased, in behaviorally aged impaired versus unimpaired rodents it can decrease or increase and finally, it is increased in rodents grown in enriched environments. Different factors explain these contradictory results in both animals and humans, among others concomitant psychiatric endophenotypes, such as depression. The possible involvement of PSD-95 in reactive and/or compensatory mechanisms during AD progression is underscored, at least before the occurrence of important synaptic elimination. Thus, in AD but not in AD transgenic mice, enhanced expression might precede the diminution commonly observed in advanced aging. A two-compartments cell model, separating events taking place in cell bodies and synapses, is presented. Overall these data suggest that AD research will progress by untangling pathological from protective events, a prerequisite for effective therapeutic strategies.
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This paper presents a thermal modeling for power management of a new three-dimensional (3-D) thinned dies stacking process. Besides the high concentration of power dissipating sources, which is the direct consequence of the very interesting integration efficiency increase, this new ultra-compact packaging technology can suffer of the poor thermal conductivity (about 700 times smaller than silicon one) of the benzocyclobutene (BCB) used as both adhesive and planarization layers in each level of the stack. Thermal simulation was conducted using three-dimensional (3-D) FEM tool to analyze the specific behaviors in such stacked structure and to optimize the design rules. This study first describes the heat transfer limitation through the vertical path by examining particularly the case of the high dissipating sources under small area. First results of characterization in transient regime by means of dedicated test device mounted in single level structure are presented. For the design optimization, the thermal draining capabilities of a copper grid or full copper plate embedded in the intermediate layer of stacked structure are evaluated as a function of the technological parameters and the physical properties. It is shown an interest for the transverse heat extraction under the buffer devices dissipating most the power and generally localized in the peripheral zone, and for the temperature uniformization, by heat spreading mechanism, in the localized regions where the attachment of the thin die is altered. Finally, all conclusions of this analysis are used for the quantitative projections of the thermal performance of a first demonstrator based on a three-levels stacking structure for space application.
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Whereas numerical modeling using finite-element methods (FEM) can provide transient temperature distribution in the component with enough accuracy, it is of the most importance the development of compact dynamic thermal models that can be used for electrothermal simulation. While in most cases single power sources are considered, here we focus on the simultaneous presence of multiple sources. The thermal model will be in the form of a thermal impedance matrix containing the thermal impedance transfer functions between two arbitrary ports. Eachindividual transfer function element ( ) is obtained from the analysis of the thermal temperature transient at node ¿ ¿ after a power step at node ¿ .¿ Different options for multiexponential transient analysis are detailed and compared. Among the options explored, small thermal models can be obtained by constrained nonlinear least squares (NLSQ) methods if the order is selected properly using validation signals. The methods are applied to the extraction of dynamic compact thermal models for a new ultrathin chip stack technology (UTCS).
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We predict the existence of an anomalous crossover between thermal and shot noise in macroscopic diffusive conductors. We first show that, besides thermal noise, these systems may also exhibit shot noise due to fluctuations of the total number of carriers in the system. Then we show that at increasing currents the crossover between the two noise behaviors is anomalous, in the sense that the low-frequency current spectral density displays a region with a superlinear dependence on the current up to a cubic law. The anomaly is due to the nontrivial coupling in the presence of the long-range Coulomb interaction among the three time scales relevant to the phenomenon, namely, diffusion, transit, and dielectric relaxation time.
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Within a drift-diffusion model we investigate the role of the self-consistent electric field in determining the impedance field of a macroscopic Ohmic (linear) resistor made by a compensated semi-insulating semiconductor at arbitrary values of the applied voltage. The presence of long-range Coulomb correlations is found to be responsible for a reshaping of the spatial profile of the impedance field. This reshaping gives a null contribution to the macroscopic impedance but modifies essentially the transition from thermal to shot noise of a macroscopic linear resistor. Theoretical calculations explain a set of noise experiments carried out in semi-insulating CdZnTe detectors.
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The study of the thermal behavior of complex packages as multichip modules (MCM¿s) is usually carried out by measuring the so-called thermal impedance response, that is: the transient temperature after a power step. From the analysis of this signal, the thermal frequency response can be estimated, and consequently, compact thermal models may be extracted. We present a method to obtain an estimate of the time constant distribution underlying the observed transient. The method is based on an iterative deconvolution that produces an approximation to the time constant spectrum while preserving a convenient convolution form. This method is applied to the obtained thermal response of a microstructure as analyzed by finite element method as well as to the measured thermal response of a transistor array integrated circuit (IC) in a SMD package.