1,640 research outputs found
Airborne Advanced Reconfigurable Computer System (ARCS)
A digital computer subsystem fault-tolerant concept was defined, and the potential benefits and costs of such a subsystem were assessed when used as the central element of a new transport's flight control system. The derived advanced reconfigurable computer system (ARCS) is a triple-redundant computer subsystem that automatically reconfigures, under multiple fault conditions, from triplex to duplex to simplex operation, with redundancy recovery if the fault condition is transient. The study included criteria development covering factors at the aircraft's operation level that would influence the design of a fault-tolerant system for commercial airline use. A new reliability analysis tool was developed for evaluating redundant, fault-tolerant system availability and survivability; and a stringent digital system software design methodology was used to achieve design/implementation visibility
Quantum critical behavior in the heavy Fermion single crystal Ce(NiPd)Ge
We have performed magnetic susceptibility, specific heat, resistivity, and
inelastic neutron scattering measurements on a single crystal of the heavy
Fermion compound Ce(NiPd)Ge, which is believed to
be close to a quantum critical point (QCP) at T = 0. At lowest
temperature(1.8-3.5 K), the magnetic susceptibility behaves as with m/mole
(0.0025 emu/mole). For 1 K, the specific heat can be fit to the formula
with of order 700 mJ/mole-K.
The resistivity behaves as for temperatures below 2
K. This low temperature behavior for and is in accord
with the SCR theory of Moriya and Takimoto\cite{Moriya}. The inelastic neutron
scattering spectra show a broad peak near 1.5 meV that appears to be
independent of ; we interpret this as Kondo scattering with 17 K. In
addition, the scattering is enhanced near =(1/2, 1/2, 0) with maximum
scattering at = 0.45 meV; we interpret this as scattering from
antiferromagnetic fluctuations near the antiferromagnetic QCP.Comment: to be published in J. Phys: Conference Serie
Strategic Shift to a Diagnostic Model of Care in a Multi-Site Group Dental Practice.
BackgroundDocumenting standardized dental diagnostic terms represents an emerging change for how dentistry is practiced. We focused on a mid-sized dental group practice as it shifted to a policy of documenting patients' diagnoses using standardized terms in the electronic health record.MethodsKotter's change framework was translated into interview questions posed to the senior leadership in a mid-size dental group practice. In addition, quantitative content analyses were conducted on the written policies and forms before and after the implementation of standardized diagnosis documentation to assess the extent to which the forms and policies reflected the shift. Three reviewers analyzed the data individually and reached consensuses where needed.ResultsKotter's guiding change framework explained the steps taken to 97 percent utilization rate of the Electronic Health Record and Dental Diagnostic Code. Of the 96 documents included in the forms and policy analysis, 31 documents were officially updated but only two added a diagnostic element.ConclusionChange strategies established in the business literature hold utility for dental practices seeking diagnosis-centered care.Practical implicationsA practice that shifts to a diagnosis-driven care philosophy would be best served by ensuring that the change process follows a leadership framework that is calibrated to the organization's culture
Recommended from our members
Ceramic/polymer functionally graded material (FGM) lightweight armor system
This is the final report of a two-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Functionally graded material is an enabling technology for lightweight body armor improvements. The objective was to demonstrate the ability to produce functionally graded ceramic-polymer and ceramic-metal lightweight armor materials. This objective involved two aspects. The first and key aspect was the development of graded-porosity boron-carbide ceramic microstructures. The second aspect was the development of techniques for liquid infiltration of lightweight metals and polymers into the graded-porosity ceramic. The authors were successful in synthesizing boron-carbide ceramic microstructures with graded porosity. These graded-porosity boron-carbide hot-pressed pieces were then successfully liquid-infiltrated in vacuum with molten aluminum at 1,300 C, and with liquid polymers at room temperature. Thus, they were able to demonstrate the feasibility of producing boron carbide-aluminum and boron carbide-polymer functionally graded materials
Stimulation of Adenosine A 3 Receptors in Cerebral Ischemia: Neuronal Death, Recovery, or Both?
The role of the adenosine A 3 receptor continues to baffle, and, despite an increasing number of studies, the currently available data add to, rather than alleviate, the existing confusion. The reported effects of adenosine A 3 receptor stimulation appear to depend on the pattern of drug administration (acute vs. chronic), dose, and type of the target tissue. Thus, while acute exposure to A 3 receptor agonists protects against myocardial ischemia, it is severely damaging when these agents are given shortly prior to cerebral ischemia. Mast cells degranulate when their A 3 receptors are stimulated. Degranulation of neutrophils is, on the other hand, impaired. While reduced production of reactive nitrogen species has been reported following activation of A 3 receptors in collagen-induced arthritis, the process appears to be enhanced in cerebral ischemia. Indeed, immunocytochemical studies indicate that both pre- and postischemic treatment with A 3 receptor antagonist dramatically reduces nitric oxide synthase in the affected hippocampus. Even more surprisingly, low doses of A 3 receptor agonists seem to enhance astrocyte proliferation, while high doses induce their apoptosis. This review concentrates on the studies of cerebral A 3 receptors and, based on the available evidence, discusses the possibility of adenosine A 3 receptor serving as an integral element of the endogenous cerebral neuroprotective complex consisting of adenosine and its receptors.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75391/1/j.1749-6632.1999.tb07984.x.pd
Recommended from our members
Fabrication and properties of erbium oxide
Erbium oxide (Er{sub 2}O{sub 3}) is a rare earth oxide of interest because of its chemical and thermal stability and high melting point, 2,430 C. However, there is relatively little information available regarding the relation between the structure and the mechanical properties of this material. A densification study of polycrystalline erbium oxide powders is reported here. Erbium oxide pellets were uniaxially pressed (40--280 MPa) and sintered (1,500--1,800 C) in order to obtain density data for as-received commercial powders. In addition, the particle size and distribution of as-received powders were varied by milling and the effects on densification were studied. The powders were characterized for particle size, phase and impurity content and surface area. The mechanical properties of high density sintered erbium oxide bodies were characterized using indentation hardness and toughness as a function of temperature and microstructure. Relations between the microstructure and mechanical properties are described
Recommended from our members
Functionally graded boron carbide
Lightweight body armor is important for the protection of US soldiers in the field. Here, fabrication techniques were developed for producing graded porosity B{sub 4}C, and for producing aluminum-B{sub 4}C and epoxy-B{sub 4}C functionally graded materials. The key fabrication aspect was obtaining the graded porosity B{sub 4}C. The feasibility of producing graded porosity B{sub 4}C using a grading of carbon densification aid produced from a gradient of furfuryl alcohol carbon precursor was demonstrated. This approach is quite promising, but it was not optimized in the present investigation. Graded porosity B{sub 4}C materials were produced by a layering approach using different size distributions of B{sub 4}C powders in the green state, and then densifying the layered assembly by hot pressing at 1,900 C. The hardness of uninfiltrated graded B{sub 4}C, aluminum infiltrated B{sub 4}C, and epoxy infiltrated B{sub 4}C was observed to be similar
- …