1,012 research outputs found
Study of Multimission Modular Spacecraft (MMS) propulsion requirements
The cost effectiveness of various propulsion technologies for shuttle-launched multimission modular spacecraft (MMS) missions was determined with special attention to the potential role of ion propulsion. The primary criterion chosen for comparison for the different types of propulsion technologies was the total propulsion related cost, including the Shuttle charges, propulsion module costs, upper stage costs, and propulsion module development. In addition to the cost comparison, other criteria such as reliability, risk, and STS compatibility are examined. Topics covered include MMS mission models, propulsion technology definition, trajectory/performance analysis, cost assessment, program evaluation, sensitivity analysis, and conclusions and recommendations
Studies and analyses of the space shuttle main engine: High-pressure oxidizer turbopump failure information propagation model
The high-pressure oxidizer turbopump (HPOTP) failure information propagation model (FIPM) is presented. The text includes a brief discussion of the FIPM methodology and the various elements which comprise a model. Specific details of the HPOTP FIPM are described. Listings of all the HPOTP data records are included as appendices
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Engineering Development of Slurry Bubble Column Reactor (SBCR) Technology. Quarterly Report, January 1--March 31, 1996
The major technical objectives of this program are threefold: (1) to develop the design tools and a fundamental understanding of the fluid dynamics of a slurry bubble column reactor to maximize reactor productivity; (2) to develop the mathematical reactor design models and gain an understanding of the hydrodynamic fundamentals under industrially relevant process conditions; and (3) to develop an understanding of the hydrodynamics and their interaction with the chemistries occurring in the bubble column reactor. Successful completion of these objectives will permit more efficient usage of the reactor column and tighter design criteria, increase overall reactor efficiency, and ensure a design that leads to stable reactor behavior when scaling up to large diameter reactors. The main part of this report describes tracer studies of slurry bubble column hydrodynamics during methanol synthesis
Sustainable and conventional banking in Europe
At the end of the 20th century a new banking model, the so-called ethical banking, emerged becoming the maximum exponent of a socially responsible investment. The financial crisis in 2008 led to a distrust of the conventional financial system and consequently investors began to look with interest this new banking, which only invests in ethical activities and products, with social and environmental criteria, total transparency and a democratic management. The aim of this article is to analyze the economic structure of ethical banking, compared to that of conventional banking, by paying attention to its liquidity, coverage and solvency. Specifically, We compare the financial statements of Triodos Bank, the main European ethical bank belonging to the Global Alliance for Banking on Values, with two of the main conventional banks of each of the five countries in Europe in which it operates. To do this, we apply a financial and economic analysis to the period from 2015 to 2018, the means difference test and analysis of variance on an array of financial ratios and, finally, probit regressions. The results reveal that ethical banking is growing more than conventional banking and it presents greater liquidity and solvency, although, in general terms, its profitability is not higher. In conclusion, both savers and investors have guarantees that their savings are invested not only in a responsible but also in a confident way in ethical banking
Mortality of Patients with Hematological Malignancy after Admission to the Intensive Care Unit
Background: The admission of patients with malignancies to an intensive care unit (ICU) still remains a matter of substantial controversy. The identification of factors that potentially influence the patient outcome can help ICU professionals make appropriate decisions. Patients and Methods: 90 adult patients with hematological malignancy (leukemia 47.8%, high-grade lymphoma 50%) admitted to the ICU were analyzed retrospectively in this single-center study considering numerous variables with regard to their influence on ICU and day-100 mortality. Results: The median simplified acute physiology score (SAPS) II at ICU admission was 55 (ICU survivors 47 vs. 60.5 for non-survivors). The overall ICU mortality rate was 45.6%. With multivariate regression analysis, patients admitted with sepsis and acute respiratory failure had a significantly increased ICU mortality (sepsis odds ratio (OR) 9.12, 95% confidence interval (CI) 1.1-99.7, p = 0.04; respiratory failure OR 13.72, 95% CI 1.39-136.15, p = 0.025). Additional factors associated with an increased mortality were: high doses of catecholamines (ICU: OR 7.37, p = 0.005; day 100: hazard ratio (HR) 2.96, p < 0.0001), renal replacement therapy (day 100: HR 1.93, p = 0.026), and high SAPS II (ICU: HR 1.05, p = 0.038; day 100: HR 1.2, p = 0.027). Conclusion: The decision for or against ICU admission of patients with hematological diseases should become increasingly independent of the underlying malignant disease
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Commentary: What We Know About Stemflow's Infiltration Area
[No abstract available
The human genome: a multifractal analysis
<p>Abstract</p> <p>Background</p> <p>Several studies have shown that genomes can be studied via a multifractal formalism. Recently, we used a multifractal approach to study the genetic information content of the <it>Caenorhabditis elegans </it>genome. Here we investigate the possibility that the human genome shows a similar behavior to that observed in the nematode.</p> <p>Results</p> <p>We report here multifractality in the human genome sequence. This behavior correlates strongly on the presence of Alu elements and to a lesser extent on CpG islands and (G+C) content. In contrast, no or low relationship was found for LINE, MIR, MER, LTRs elements and DNA regions poor in genetic information. Gene function, cluster of orthologous genes, metabolic pathways, and exons tended to increase their frequencies with ranges of multifractality and large gene families were located in genomic regions with varied multifractality. Additionally, a multifractal map and classification for human chromosomes are proposed.</p> <p>Conclusions</p> <p>Based on these findings, we propose a descriptive non-linear model for the structure of the human genome, with some biological implications. This model reveals 1) a multifractal regionalization where many regions coexist that are far from equilibrium and 2) this non-linear organization has significant molecular and medical genetic implications for understanding the role of Alu elements in genome stability and structure of the human genome. Given the role of Alu sequences in gene regulation, genetic diseases, human genetic diversity, adaptation and phylogenetic analyses, these quantifications are especially useful.</p
Soft capacitor fibers using conductive polymers for electronic textiles
A novel, highly flexible, conductive polymer-based fiber with high electric
capacitance is reported. In its crossection the fiber features a periodic
sequence of hundreds of conductive and isolating plastic layers positioned
around metallic electrodes. The fiber is fabricated using fiber drawing method,
where a multi-material macroscopic preform is drawn into a sub-millimeter
capacitor fiber in a single fabrication step. Several kilometres of fibers can
be obtained from a single preform with fiber diameters ranging between 500um
-1000um. A typical measured capacitance of our fibers is 60-100 nF/m and it is
independent of the fiber diameter. For comparison, a coaxial cable of the
comparable dimensions would have only ~0.06nF/m capacitance. Analysis of the
fiber frequency response shows that in its simplest interrogation mode the
capacitor fiber has a transverse resistance of 5 kOhm/L, which is inversely
proportional to the fiber length L and is independent of the fiber diameter.
Softness of the fiber materials, absence of liquid electrolyte in the fiber
structure, ease of scalability to large production volumes, and high
capacitance of our fibers make them interesting for various smart textile
applications ranging from distributed sensing to energy storage
Understanding Sulfur Poisoning of Bimetallic Pd-Pt Methane Oxidation Catalysts and their Regeneration
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