Study of the costs and benefits of composite materials in advanced turbofan engines

Composite component designs were developed for a number of applicable engine parts and functions. The cost and weight of each detail component was determined and its effect on the total engine cost to the aircraft manufacturer was ascertained. The economic benefits of engine or nacelle composite or eutectic turbine alloy substitutions was then calculated. Two time periods of engine certification were considered for this investigation, namely 1979 and 1985. Two methods of applying composites to these engines were employed. The first method just considered replacing an existing metal part with a composite part with no other change to the engine. The other method involved major engine redesign so that more efficient composite designs could be employed. Utilization of polymeric composites wherever payoffs were available indicated that a total improvement in Direct Operating Cost (DOC) of 2.82 to 4.64 percent, depending on the engine considered, could be attained. In addition, the percent fuel saving ranged from 1.91 to 3.53 percent. The advantages of using advanced materials in the turbine are more difficult to quantify but could go as high as an improvement in DOC of 2.33 percent and a fuel savings of 2.62 percent. Typically, based on a fleet of one hundred aircraft, a percent savings in DOC represents a savings of four million dollars per year and a percent of fuel savings equals 23,000 cu m (7,000,000 gallons) per year

Quiet engine program flight engine design study

The results are presented of a preliminary flight engine design study based on the Quiet Engine Program high-bypass, low-noise turbofan engines. Engine configurations, weight, noise characteristics, and performance over a range of flight conditions typical of a subsonic transport aircraft were considered. High and low tip speed engines in various acoustically treated nacelle configurations were included

Energy efficient engine: Preliminary design and integration studies

Parametric design and mission evaluations of advanced turbofan configurations were conducted for future transport aircraft application. Economics, environmental suitability and fuel efficiency were investigated and compared with goals set by NASA. Of the candidate engines which included mixed- and separate-flow, direct-drive and geared configurations, an advanced mixed-flow direct-drive configuration was selected for further design and evaluation. All goals were judged to have been met except the acoustic goal. Also conducted was a performance risk analysis and a preliminary aerodynamic design of the 10 stage 23:1 pressure ratio compressor used in the study engines

"Stay at Home and Live with Integrity": Advice to German Emigrants to the United States from the Journeymen’s Father

In recent decades, American historians have asserted that a broad chasm existed between the rhetoric of equality in Jacksonian America and the actual economic reality that existed. Several years ago, Edward Pessen observed that the so-called Era of the Common Man brought no startling social or economic improvements for the common sort of people. More recently, authors like Alan Dawley, Paul E. Johnson, and Sean Wilentz have argued that not only was there no improvement in the conditions for working men, but the universe of options for skilled journeymen was undergoing a radical contraction, which endangered their integrity as an independent productive class.* Furthermore, eroding economic conditions seem to have led to a decline in the commitment to democratic ideology. Michael Holt posits that economic dislocation of the artisan class as a result of the industrial revolution and increased pressure for jobs created by rising immigration led many Americans to support programs which were designed to reduce immigration, or at least to reduce the political influence of incoming immigrants. This support resulted in the rise of such antidemocratic organizations as the nativist societies which eventually formed the American Know-Nothing party.

Stay at Home and Live with Integrity : Advice to German Emigrants to the United States from the Journeymen’s Father

In recent decades, American historians have asserted that a broad chasm existed between the rhetoric of equality in Jacksonian America and the actual economic reality that existed. Several years ago, Edward Pessen observed that the so-called Era of the Common Man brought no startling social or economic improvements for the common sort of people. More recently, authors like Alan Dawley, Paul E. Johnson, and Sean Wilentz have argued that not only was there no improvement in the conditions for working men, but the universe of options for skilled journeymen was undergoing a radical contraction, which endangered their integrity as an independent productive class.* Furthermore, eroding economic conditions seem to have led to a decline in the commitment to democratic ideology. Michael Holt posits that economic dislocation of the artisan class as a result of the industrial revolution and increased pressure for jobs created by rising immigration led many Americans to support programs which were designed to reduce immigration, or at least to reduce the political influence of incoming immigrants. This support resulted in the rise of such antidemocratic organizations as the nativist societies which eventually formed the American Know-Nothing party.

Estudo da cinética de multiplicação e de viabilidade celular de Saccharomyces cerevisiae.

Resumo

Transient, Non-Axisymmetric Modes in Instability of Unsteady Circular Couette Flow

Laboratory and numerical experiments were conducted to quantitatively determine the modal structure of transient, nonaxisymmetric modes observed during the instability of an impulsively initiated circular‐Couette flow. The instability develops initially as an axisymmetric, Görtler‐vortex state and persists ultimately as a steady, axisymmetric Taylor‐vortex state of different wavelength. The transition between these two states results from the instability of the Görtler mode combined with the underlying developing swirl flow and is dominated by nonaxisymmetric modes. The laboratory experiments employed flow visualization coupled with digital video and image‐processing techniques; numerical experiments were performed using the spectral‐element code

Hanford Site National Environmental Policy Act (NEPA) characterization. Revision 9

This ninth revision of the Hanford Site National Environmental Policy Act (NEPA) Characterization presents current environmental data regarding the hanford Site and its immediate environs. This information is intended for use in preparing Chapters 4 and 6 in Hanford Site-related NEPA documents. Chapter 4.0 (Affected Environment) includes information on climate and meteorology, geology, hydrology, ecology, cultural, archaeological and historical resources, socioeconomics, and noise. Chapter 6.0 (Statutory and Regulatory Requirements) provides the preparer with the federal and state regulations, DOE directives and permits, and environmental standards directly applicable to the NEPA documents on the Hanford Site. Not all of the sections have been updated for this revision. The following lists the updated sections: climate and meteorology; ecology (threatened and endangered species section only); culture, archaeological, and historical resources; socioeconomics; all of Chapter 6

Distinctive correspondence between separable visual attention functions and intrinsic brain networks

Separable visual attention functions are assumed to rely on distinct but interacting neural mechanisms. Bundesen's “theory of visual attention” (TVA) allows the mathematical estimation of independent parameters that characterize individuals' visual attentional capacity (i.e., visual processing speed and visual short-term memory storage capacity) and selectivity functions (i.e., top-down control and spatial laterality). However, it is unclear whether these parameters distinctively map onto different brain networks obtained from intrinsic functional connectivity, which organizes slowly fluctuating ongoing brain activity. In our study, 31 demographically homogeneous healthy young participants performed whole- and partial-report tasks and underwent resting-state functional magnetic resonance imaging (rs-fMRI). Report accuracy was modeled using TVA to estimate, individually, the four TVA parameters. Networks encompassing cortical areas relevant for visual attention were derived from independent component analysis of rs-fMRI data: visual, executive control, right and left frontoparietal, and ventral and dorsal attention networks. Two TVA parameters were mapped on particular functional networks. First, participants with higher (vs. lower) visual processing speed showed lower functional connectivity within the ventral attention network. Second, participants with more (vs. less) efficient top-down control showed higher functional connectivity within the dorsal attention network and lower functional connectivity within the visual network. Additionally, higher performance was associated with higher functional connectivity between networks: specifically, between the ventral attention and right frontoparietal networks for visual processing speed, and between the visual and executive control networks for top-down control. The higher inter-network functional connectivity was related to lower intra-network connectivity. These results demonstrate that separable visual attention parameters that are assumed to constitute relatively stable traits correspond distinctly to the functional connectivity both within and between particular functional networks. This implies that individual differences in basic attention functions are represented by differences in the coherence of slowly fluctuating brain activity

COMPETITION AMONG HOSPITALS AND ITS MEASUREMENT: THEORY AND A CASE STUDY

Our paper provides several insights on the characteristics of the concept of “Poles d’Excellence Rurale” (PER) through bilateral comparisons with that of Competitive Pole (CP) and cluster. The concept of PER is a French government’ initiative designed for the development of rural areas similar to that of the Competitive Pole. We emphasize important particularities of these concepts by analyzing some of their similarities and major differences.Pole d’Excellence Rurale, Competitive Pole, cluster, rural development