3,198 research outputs found
The Liege-balloon program
The Liege-balloon program is intended to make high-spectral resolution observations of the sun in the near- and intermediate infrared regions not accessible from the ground. A description of the equipment, followed by a summary of the data obtained till now is presented. Except for ozone whose maximum of concentration lies near 25 Km altitude, the residual mass distribution of the other mentioned molecules decreases with altitude. This is a self-explanatory argument for carrying out spectroscopic observations from platforms transcending the densest layers of the earth's atmosphere. The Liege balloon equipment is primarily intended for very high-resolution solar observations from about 27-30 Km altitude, in all spectral regions between 1.5 and 15.0 microns, not accessible from the ground
Entanglement and the Quantum Brachistochrone Problem
Entanglement is closely related to some fundamental features of the dynamics
of composite quantum systems: quantum entanglement enhances the "speed" of
evolution of certain quantum states, as measured by the time required to reach
an orthogonal state. The concept of "speed" of quantum evolution constitutes an
important ingredient in any attempt to determine the fundamental limits that
basic physical laws impose on how fast a physical system can process or
transmit information. Here we explore the relationship between entanglement and
the speed of quantum evolution in the context of the quantum brachistochrone
problem. Given an initial and a final state of a composite system we consider
the amount of entanglement associated with the brachistochrone evolution
between those states, showing that entanglement is an essential resource to
achieve the alluded time-optimal quantum evolution.Comment: 6 pages, 3 figures. Corrected typos in Eqs. 1 and
Optimization of the indications for allogeneic stem cell transplantation in Acute Myeloid Leukemia based on interactive diagnostic strategies
The indications for allogeneic stem cell transplantation (SCT) in Acute Myeloid Leukemia (AML) represent a real challenge due to the clinical and genetic heterogeneity of the disorder. Therefore, an optimized indication for SCT in AML first requires the determination of the individual relapse risk based on diverse chromosomal and molecular prognosis-defining aberrations. A broad panel of diagnostic methods is needed to allow such subclassification and prognostic stratification: cytomorphology, cytogenetics, molecular genetics, and immunophenotyping by multiparameter flow cytometry. These methods should not be seen as isolated techniques but as parts of an integral network with hierarchies and interactions. Examples for a poor risk constellation as a clear indication for allogeneic SCT are provided by anomalies of chromosome 7, complex aberrations, or FLT3-length mutations. In contrast, the favorable reciprocal translocations such as the t(15;17)/PML-RARA or t(8;21)/AML1-ETO are not indications for SCT in first remission due to the rather good prognosis after standard therapy. Further, the indication for SCT should include the results of minimal residual disease (MRD) diagnostics by polymerase chain reaction (PCR) or flow cytometry. New aspects for a safe and fast risk stratification as basis for an optimized indication for SCT in AML might be provided by novel technologies such as microarray-based gene expression profiling. Keywords: Acute Myeloid Leukemia (AML), Allogeneic Stem Cell Transplantation (SCT), Indication, Cytogenetics, Polymerase Chain Reaction (PCR
Transient Heat Analysis of a Carbon Composite Scramjet Combustion Chamber
A preliminary 2D transient analysis for a predicted trajectory in a representative scramjet flight path is presented. This model incorporates hypersonic convection and radiation heat transfer at the combustor walls and heat transfer to the fuel which is used as an endothermic heat sink. A heavy hydrocarbon fuel is selected due to the high density and energy release required for combustion, whilst still providing the necessary heat sink for cooling. In this process the fuel can be cracked to smaller carbon chained molecules for improved ignition and combustion. This analysis will be used in parallel with materials development to ensure appropriate composites are available in Australia for flight structures. The results show that for a postulated Mach 8 scramjet flight at 27km altitude that a combustor structure comprising of 1mm RCC, 1mm graphite foam insulation and a 3mm inconel fuel manifold the maximum temperatures reached are of the order of 1950K in the RCC. This falls within the temperature range allowed for the chosen materials to ensure that structural integrity is maintained. These results justify the further investigation into the use of composite materials and regenerative cooling with the aim of potentially using the analysis for the design of flight vehicles, including the upcoming HiFire series of experiments
Methods for Assessing Energy Efficiency of Buildings
This article analyzes the case of a Brazilian Institute of Higher Education, in relation to compliance with a normative instruction, according to which all federal public buildings must follow the rules of energy efficiency. The aim of this work is to demonstrate the potential of Building Information Modeling to optimize the execution of reference
instructions. As a case study, the energy efficiency of one of the Institute buildings was observed using the conventional method and a new method. Subsequently, a comparative analysis was carried out to indicate the most appropriate procedure for the Institute. Finally, it was observed that the new method showed an approximately 85% reduction in classification time due to its better performance in obtaining architectural design information and, if incorporated in the routine of the project, will contribute more adequately to the interests of the Institute
Measurements of CH4, N2O, CO, H2O and O3 in the middle atmosphere by the ATMOS experiment on Spacelab 3
The volume mixing ratios of five minor gases (CH4, N2O, CO, H2O, and O3) were retrieved through the middle atmosphere from the analysis of 0.01/cm resolution infrared solar occultation spectra recorded near 28 N and 48 S latitudes with the ATMOS (Atmospheric Trace Molecule Spectroscopy) instrument, flown on board Spacelab 3. The results, which constitute the first simultaneous observations of continuous profiles through the middle atmosphere for these gases, are in general agreement with reported measurements from ground, balloon and satellite-based instruments for the same seasons. In detail, the vertical profiles of these gases show the effects of the upper and middle atmospheric transport patterns dominant during the season of these observations. The profiles inferred at different longitudes around 28 N suggest a near-uniform zonal distribution of these gases. Although based on fewer observations, the sunrise occultation measurements point to a larger variability in the vertical distribution of these gases at 48 S
Analysis of controlled source electromagnetic data in the Black Sea: Regularized 2-D inversion with seismic constraints and trans-dimensional Bayesian inversion to estimate uncertainties
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