3,460 research outputs found

    Composition and sensory properties of Cabernet Sauvignon wine aged in French versus American oak barrels

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    Cabernet Sauvignon wine aged in similarly coopered, lightly charred French and American oak barrels had increased titratable acidity and decreased pH values over the control glass-aged wine, which was primarily the result of extraction of acid from the wood. Extracted volatile acids accounted for 22.5 and 27.5 % of the increase in titratable acidity in American and French barrels, respectively. As with the pH and titratable acidity changes, the increase in total and nonflavonoid phenols extracted from the barrels was greater in the French than in the American oak-aged wines. Potassium increased significantly with barre! aging in the American oak samples, with no significant difference occuring between the control and the French. In sensory difference tests, all oak-aged wines could be discriminated from the glass-aged control. However, in comparing wines aged in French and American oak for the same time, only those aged for 115 d were significantly different (P < 0.05).Zusammensetzung und sensorische Eigenschaften von Cabernet-Sauvignon-Wein nach Lagerung in französischen und amerikanischen EichenfässernKalifornischer Cabernet-Sauvignon-Wein des Jahrgangs 1980 wurde 115, 239 und 338 d lang in neuen Eichenfässern (228 1) gelagert, die in den USA (Missouri) und Frankreich (Nevers) nach ähnlichen Verfahren gefertigt worden waren. Wein, der in 19-1-Glasballons unter denselben Bedingungen gelagert wurde, diente als Kontrolle. Die Eichenfaß-gelagerten Weine besaßen signifikant höhere Gehalte an titrierbarer Säure (TA), flüchtiger Säure (VA), Äthanol, Gesamtphenolen (TP), polymeren Phenolen (PP) und nicht-flavonoiden Phenolen (NFP) als die Kontrolle. In französischen Eichenfässern gelagerter Wein zeigte einen signifikant niedrigeren Kaliumspiegel und signifikant höhere Gehalte an TA, VA, TP und NFP als Wein aus amerikanischen Fässern. Während die erhöhte Äthanolkonzentration durch die Verdunstung von Wasser zustande kam, stieg der Gehalt an TA, VA, TP und NFP hauptsächlich infolge der Extraktion aus dem Eichenholz an. Die signifikant höheren Werte der PP waren das Ergebnis einer schnelleren Polymerisierung von flavonoiden Weinphenolen in den Eichengebinden. Im sensorischen Triangeltest unterschied sich der Kontrollwein signifikant von beiden faßgelagerten Weinen; ein Vergleich der Weine, die gleich lang in französischen und amerikanischen Eichenfässern lagerten, zeigte nur bei den 115 d lang gelagerten Weinen einen signifikanten Unterschied

    Helicopter mathematical models and control law development for handling qualities research

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    Progress made in joint NASA/Army research concerning rotorcraft flight-dynamics modeling, design methodologies for rotorcraft flight-control laws, and rotorcraft parameter identification is reviewed. Research into these interactive disciplines is needed to develop the analytical tools necessary to conduct flying qualities investigations using both the ground-based and in-flight simulators, and to permit an efficient means of performing flight test evaluation of rotorcraft flying qualities for specification compliance. The need for the research is particularly acute for rotorcraft because of their mathematical complexity, high order dynamic characteristics, and demanding mission requirements. The research in rotorcraft flight-dynamics modeling is pursued along two general directions: generic nonlinear models and nonlinear models for specific rotorcraft. In addition, linear models are generated that extend their utilization from 1-g flight to high-g maneuvers and expand their frequency range of validity for the design analysis of high-gain flight control systems. A variety of methods ranging from classical frequency-domain approaches to modern time-domain control methodology that are used in the design of rotorcraft flight control laws is reviewed. Also reviewed is a study conducted to investigate the design details associated with high-gain, digital flight control systems for combat rotorcraft. Parameter identification techniques developed for rotorcraft applications are reviewed

    Rotorcraft handling-qualities design criteria development

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    Joint NASA/Army efforts at the Ames Research Center to develop rotorcraft handling-qualities design criteria began in earnest in 1975. Notable results were the UH-1H VSTOLAND variable stability helicopter, the VFA-2 camera-and-terrain-board simulator visual system, and the generic helicopter real-time mathematical model, ARMCOP. An initial series of handling-qualities studies was conducted to assess the effects of rotor design parameters, interaxis coupling, and various levels of stability and control augmentation. The ability to conduct in-flight handling-qualities research was enhanced by the development of the NASA/Army CH-47 variable-stability helicopter. Research programs conducted using this vehicle include vertical-response investigations, hover augmentation systems, and the effects of control-force characteristics. The handling-qualities data base was judged to be sufficient to allow an update of the military helicopter handling-qualities specification, MIL-H-8501. These efforts, including not only the in-house experimental work but also contracted research and collaborative programs performed under the auspices of various international agreements. The report concludes by reviewing the topics that are currently most in need of work, and the plans for addressing these topics

    Rotorcraft In-Flight Simulation Research at NASA Ames Research Center: A Review of the 1980's and plans for the 1990's

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    A new flight research vehicle, the Rotorcraft-Aircrew System Concepts Airborne Laboratory (RASCAL), is being developed by the U.S. Army and NASA at ARC. The requirements for this new facility stem from a perception of rotorcraft system technology requirements for the next decade together with operational experience with the Boeing Vertol CH-47B research helicopter that was operated as an in-flight simulator at ARC during the past 10 years. Accordingly, both the principal design features of the CH-47B variable-stability system and the flight-control and cockpit-display programs that were conducted using this aircraft at ARC are reviewed. Another U.S Army helicopter, a Sikorsky UH-60A Black Hawk, was selected as the baseline vehicle for the RASCAL. The research programs that influence the design of the RASCAL are summarized, and the resultant requirements for the RASCAL research system are described. These research programs include investigations of advanced, integrated control concepts for achieving high levels of agility and maneuverability, and guidance technologies, employing computer/sensor-aiding, designed to assist the pilot during low-altitude flight in conditions of limited visibility. The approach to the development of the new facility is presented and selected plans for the preliminary design of the RASCAL are described

    Is sexism a gender issue? A motivated social cognition perspective on men’s and women’s sexist attitudes toward own and other gender

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    The present research investigated the antecedents of ambivalent sexism (i.e., hostile and benevolent forms) in both men and women toward own and other gender. In two heterogeneous adult samples (Study 1: N = 179 and Study 2: N = 222), it as revealed that gender itself was only a minor predictor of sexist attitudes compared to the substantial impact of individual differences in general motivated cognition (i.e., Need for closure). Analyses further showed that the relationship between Need for closure and sexism was mediated by social attitudes (i.e., right-wing authoritarianism and social dominance orientation), which were differently related to benevolent and hostile forms of sexism. In the discussion it is argued that sexism primarily stems from individual differences in motivated cognitive style, which relates to peoples? perspective on the social world, rather than from group differences between men and women

    Direct contact and authoritarianism as moderators between extended contact and reduced prejudice: Lower threat and greater trust as mediators

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    Using a representative sample of Dutch adults (N = 1238), we investigated the moderating influence of direct contact and authoritarianism on the potential of extended contact to reduce prejudice. As expected, direct contact and authoritarianism moderated the effect of extended contact on prejudice. Moreover, the third-order moderation effect was also significant, revealing that extended contact has the strongest effect among high authoritarians with low levels of direct contact. We identified trust and perceived threat as the mediating processes underlying these moderation effects. The present study thus attests to the theoretical and practical relevance of reducing prejudice via extended contact. The discussion focuses on the role of extended contact in relation to direct contact and authoritarianism as well as on the importance of trust in intergroup contexts

    What difference does ("good") HRM make?

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    The importance of human resources management (HRM) to the success or failure of health system performance has, until recently, been generally overlooked. In recent years it has been increasingly recognised that getting HR policy and management "right" has to be at the core of any sustainable solution to health system performance. In comparison to the evidence base on health care reform-related issues of health system finance and appropriate purchaser/provider incentive structures, there is very limited information on the HRM dimension or its impact. Despite the limited, but growing, evidence base on the impact of HRM on organisational performance in other sectors, there have been relatively few attempts to assess the implications of this evidence for the health sector. This paper examines this broader evidence base on HRM in other sectors and examines some of the underlying issues related to "good" HRM in the health sector. The paper considers how human resource management (HRM) has been defined and evaluated in other sectors. Essentially there are two sub-themes: how have HRM interventions been defined? and how have the effects of these interventions been measured in order to identify which interventions are most effective? In other words, what is "good" HRM? The paper argues that it is not only the organisational context that differentiates the health sector from many other sectors, in terms of HRM. Many of the measures of organisational performance are also unique. "Performance" in the health sector can be fully assessed only by means of indicators that are sector-specific. These can focus on measures of clinical activity or workload (e.g. staff per occupied bed, or patient acuity measures), on measures of output (e.g. number of patients treated) or, less frequently, on measures of outcome (e.g. mortality rates or rate of post-surgery complications). The paper also stresses the need for a "fit" between the HRM approach and the organisational characteristics, context and priorities, and for recognition that so-called "bundles" of linked and coordinated HRM interventions will be more likely to achieve sustained improvements in organisational performance than single or uncoordinated interventions

    Lattice-Mismatched Monolithic GAAS/INGAAS Two-Junction Solar Cells by Direct Wafer Bonding

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    Direct bonded interconnect between subcells of a lattice-mismatched III-V compound multijunction cell would enable dislocation-free active regions by confining the defect network needed for lattice mismatch accommodation to tunnel junction interfaces, while metamorphic growth inevitably results in less design flexibility and lower material quality than is desirable. The first direct-bond interconnected multijunction solar cell, a two-terminal monolithic GaAs/InGaAs two-junction solar cell, is reported and demonstrates viability of direct wafer bonding for solar cell applications. The tandem cell open-circuit voltage was approximately the sum of the subcell open-circuit voltages. This achievement shows direct bonding enables us to construct lattice-mismatched III-V multijunction solar cells and is extensible to an ultrahigh efficiency InGaP/GaAs/InGaAsP/InGaAs four-junction cell by bonding a GaAs-based lattice-matched InGaP/GaAs subcell and an InP-based lattice-matched InGaAsP/InGaAs subcell. The interfacial resistance experimentally obtained for bonded GaAs/InP smaller than 0.10 Ohm-cm^2 would result in a negligible decrease in overall cell efficiency of ~0.02%, under 1-sun illumination

    Primary and secondary contributions to aerosol light scattering and absorption in Mexico City during the MILAGRO 2006 campaign

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    A photoacoustic spectrometer, a nephelometer, an aethalometer, and an aerosol mass spectrometer were used to measure at ground level real-time aerosol light absorption, scattering, and chemistry at an urban site located in North East Mexico City (Instituto Mexicano del Petroleo, Mexican Petroleum Institute, denoted by IMP), as part of the Megacity Impact on Regional and Global Environments field experiment, MILAGRO, in March 2006. Photoacoustic and reciprocal nephelometer measurements at 532 nm accomplished with a single instrument compare favorably with conventional measurements made with an aethalometer and a TSI nephelometer. The diurnally averaged single scattering albedo at 532 nm was found to vary from 0.60 to 0.85 with the peak value at midday and the minimum value at 07:00 a.m. local time, indicating that the Mexico City plume is likely to have a net warming effect on local climate. The peak value is associated with strong photochemical generation of secondary aerosol. It is estimated that the photochemical production of secondary aerosol (inorganic and organic) is approximately 75% of the aerosol mass concentration and light scattering in association with the peak single scattering albedo. A strong correlation of aerosol scattering at 532 nm and total aerosol mass concentration was found, and an average mass scattering efficiency factor of 3.8 m<sup>2</sup>/g was determined. Comparisons of photoacoustic and aethalometer light absorption with oxygenated organic aerosol concentration (OOA) indicate a very small systematic bias of the filter based measurement associated with OOA and the peak aerosol single scattering albedo
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