5,471 research outputs found
Cold-air investigation of a 31/2-stage fan-drive turbine with a stage loading factor of 4 designed for an integral lift engine. 2: Performance of 2-, 3- and 3 1/2-stage configurations
The stage work distribution among the three stages was very close to the design value. The specific work output-mass flow characteristics of the three stages were closely matched. The efficiency of the 3 1/2 stage turbine at design specific work output and design speed was within 0.008 of the estimated value, and this agreement was felt to demonstrate the adequacy of the prediction method in the high stage loading factor regime
Identification and Estimation of Triangular Simultaneous Equations Models Without Additivity
This paper investigates identification and inference in a nonparametric structural model with instrumental variables and non-additive errors. We allow for non-additive errors because the unobserved heterogeneity in marginal returns that often motivates concerns about endogeneity of choices requires objective functions that are non-additive in observed and unobserved components. We formulate several independence and monotonicity conditions that are sufficient for identification of a number of objects of interest, including the average conditional response, the average structural function, as well as the full structural response function. For inference we propose a two-step series estimator. The first step consists of estimating the conditional distribution of the endogenous regressor given the instrument. In the second step the estimated conditional distribution function is used as a regressor in a nonlinear control function approach. We establish rates of convergence, asymptotic normality, and give a consistent asymptotic variance estimator.
More inter- and transdisciplinary research needed in agroecology
Agroecology embraces a collection of different disciplinary fields, ranging from agriculture and ecology to political theory. A stronger recognition of agroecology in agricultural research, which often has a strong production focus, could help to achieve sustainable development if more holistic and transdisciplinary research approaches are adopted
Aerodynamic effect of a honeycomb rotor tip shroud on a 50.8-centimeter-tip-diameter core turbine
A 50.8-cm-tip-diameter turbine equipped with a rotor tip shroud of hexagonal cell (or honeycomb) cross section has been tested in warm air (416 K) for a range of shroud coolant to primary flow rates. Test results were also obtained for the same turbine operated with a solid shroud for comparison. The results showed that the combined effect of the honeycomb shroud and the coolant flow was to cause a reduction of 2.8 points in efficiency at design speed, pressure ratio, and coolant flow rate. With the coolant system inactivated, the honeycomb shroud caused a decrease in efficiency of 2.3 points. These results and those obtained from a small reference turbine indicate that the dominant factor governing honeycomb tip shroud loss is the ratio of honeycomb depth to blade span. The loss results of the two shrouds could be correlated on this basis. The same honeycomb and coolant effects are expected to occur for the hot (2200 K) version of this turbine
Agroforestry Options in Northwest Vietnam
The mountainous northwest of Vietnam is home for the majority of the countryās ethnic minorities. Poverty and food insecurity are common in the region, increasing population and land scarcity have induced the expansion of agricultural areas and consequent decline of land productivity due to soil erosion and land degradation. Local farmers have begun to practice agroforestry through the introduction of high value trees into traditional cropping systems with various combinations of timber, fruit, nut forage trees and annual crops. However, because of inherent production risks and many remaining uncertainties, assessing the long-term performance of agroforestry has remained challenging. We simulated prospective system benefits of agroforestry options by developing comprehensive and holistic models that aimed to explicitly consider all relevant risks and uncertainties. The initial findings reveal model components such as drought and frost and potential extreme weather events as the primary risks to agroforestry in the region. The analysis approach is a promising tool for ex-ante assessments of other planned interventions
Applications of Two Body Dirac Equations to Hadron and Positronium Spectroscopy
We review recent applications of the Two Body Dirac equations of constraint
dynamics to meson spectroscopy and describe new extensions to three-body
problems in their use in the study of baryon spectroscopy. We outline unique
aspects of these equations for QED bound states that distinguish them among the
various other approaches to the relativistic two body problem. Finally we
discuss recent theorectial solutions of new peculiar bound states for
positronium arising from the Two Body Dirac equations of constraint dynamics,
assuming point particles for the electron and the positron.Comment: Invited talk: CST-MISC joint international symposium on particle
physics - From spacetime dynamics to phenomenology - Tokyo, March 15-16, 201
A Question of Triumph: Effectively Measuring the Success of Intelligence against Terrorism
As intelligence programs continue to be expanded in order to combat the growing threat of terrorism seen around the globe, many critics have questioned whether the success of intelligence against terrorism can be effectively measured. Through the implementation of the United States PATRIOT Act and the mass data collection programs which it created, intelligence programs have gained access to the private interactions and intentions of government officials, civilians, and businesses, foreign and domestic, while terror acts continue to occur on a, seemingly, daily basis. This article seeks to show how the success of intelligence against terrorism can, in fact, be effectively measured when examined in regard to the various aspects of terrorism it seeks to prevent; while acknowledging the continued existence of terrorist groups as a whole. It becomes clear, through the examination of the post-9/11 terror plots, attacks, and bolstered counterstrategies against them, that success of intelligence against terrorism can be effectively measured and is clearly evident
AN EXAMINATION OF RELATIONS AMONG FEAR, GUILT, SELF-COMPASSION, AND MULTICULTURAL ATTITUDES IN WHITE ADULTS
Structural racism is often perpetuated by well-intentioned White individuals who passively accept or are unaware of its existence. However, when their perceptions and understanding of the world are challenged through learning about structural racism, White people may experience emotions such as fear, and guilt, which seem to serve either a debilitating or a motivating role in multicultural attitude development. Self-compassion, which is the ability to process distressing emotions without resorting to avoidance of the emotional experience, may help White individuals work through strong negative affect that accompanies an awareness of structural racism and ultimately aid in the development of multicultural attitudes.
This hypothesized model of moderated mediation was tested using a sample of White adults (N = 240; 70.8% women, 26.3% men, 2.9% gender-expansive) who completed an online survey. Awareness of structural racism had a larger positive relationship with White guilt in individuals who endorsed lower levels of self-compassion. For individuals with high levels of self-compassion, more awareness of structural racism was associated with more fear, which in turn was associated with lower multicultural attitudes. For individuals with low levels of self-compassion, more awareness of structural racism was associated with less fear, which in turn was associated with more multicultural attitudes. Contrary to the theoretical model, the indirect effect of awareness of structural racism on multicultural attitudes through White guilt was not moderated by self-compassion. Implications and recommendations for research and practice in the field of counseling psychology are discussed
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