23,642 research outputs found
Film breakers prevent migration of aqueous potassium hydroxide in fuel cells
Electrolyte film breakers made from polytetrafluoroethylene are installed in the reactant and water vapor removal outlets of each cell and sealed by elastomers. Use of these devices in the water vapor removal cavity outlets prevents loss of KOH solution through film migration during water removal
Vent subsystem - development plan
Vent subsystem design specifications for use in fuel cell assembl
Fuel cell module development plan - Activity 145 - 205
Development plan for fuel cell modules consisting of 35 two-cell sections and incorporating static moisture control subsystems as integral part of modul
The Economic Welfare Cost of Conflict: An Empirical Assessment
War, whether external or internal, large or small, is a costly endeavor. Loss of life, loss of close friends or family, and the destruction of material possessions all play a part in the costs of war. The purpose of this paper is to capture only the material, economic welfare costs of conflict stemming from the altered path of consumption resulting from conflict. As such, our measure is quite a lower bound for the true and more encompassing welfare loss from living in a non-peaceful world. Remarkably, however, even these pure economic welfare losses from conflict are large. We find that, on average, individuals would give up over 8 percent of their current level of consumption to live in a peaceful world. Such large potential welfare gains from reducing warfare should make economists and policy-makers take note.Growth; Conflict; Welfare Costs
Normal and conormal maps in homotopy theory
Let M be a monoidal category endowed with a distinguished class of weak
equivalences and with appropriately compatible classifying bundles for monoids
and comonoids. We define and study homotopy-invariant notions of normality for
maps of monoids and of conormality for maps of comonoids in M. These notions
generalize both principal bundles and crossed modules and are preserved by nice
enough monoidal functors, such as the normaliized chain complex functor.
We provide several explicit classes of examples of homotopy-normal and of
homotopy-conormal maps, when M is the category of simplicial sets or the
category of chain complexes over a commutative ring.Comment: 32 pages. The definition of twisting structure in Appendix B has been
reformulated, leading to further slight modifications of definitions in
Section 1. To appear in HH
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Volumetric Calibration Refinement using masked back projection and image correlation superposition
This paper deals with a new, reconstruction based, approach of refining a volumetric calibration. The technique is based on a 2D cross-correlation between particle images on the sensor plane with a planar back projection from a tomographic reconstruction in the same sensor plane to determine potential disparities between the initial camera calibration and the measurement. Additive superposition of the correlation maps from different sets or particle images allows reducing the influence of noise and ghost particles such that the systematic errors in the calibration can be corrected. The different sections describe the theory, the principle processing steps and the convergence of the procedure. Furthermore, the concept is proven by simulating the entire process of the measurement chain, with the help of a synthetic comparison. The results show that disparities of over 9 pixels could be corrected to an average of below 0.1 pixels during the refinement steps. Finally, the technique demonstrates it´s potential to measured data, where the numbers of outliers in the raw results are reduced after the volumetric calibration refinement
Multiloop Manual Control of Dynamic Systems
Human interaction with a simple, multiloop dynamic system in which the human's activity was systematically varied by changing the levels of automation was studied. The control loop structure resulting from the task definition parallels that for any multiloop manual control system, is considered a sterotype. Simple models of the human in the task, and upon extending a technique for describing the manner in which the human subjectively quantifies his opinion of task difficulty were developed. A man in the loop simulation which provides data to support and direct the analytical effort is presented
What’s in a Name?
Plenty. This paper analyzes two broad questions: Does your first name matter? And how did you get your first name anyway? Using data from the National Opinion Research Centers (NORC’s) General Social Survey, including access to respondents first names from the 1994 and 2002 surveys, we extract the important “first name features” (FNF), e.g. popularity, number of syllables, phonetic features, Scrabble score, “blackness” (i.e. the fraction of people with that name who are black), etc ... We then explore whether these first name features are useful explanatory factors of a respondent’s exogenous background factors (sex, race, parents’ education, etc...) and lifetime outcomes (e.g. financial status, occupational prestige, perceived social class, education, happiness, and whether they became a parent before 25). We find that first name features on their own do have significant predictive power for a number of these lifetime outcomes, even after controlling for a myriad of exogenous background factors. We find evidence that first name features are independent predictors of lifetime outcomes that are likely related to labor productivity such as education, happiness and early fertility. Importantly, however, we also find evidence based on the differential impacts of gender and race on the blackness of a name and its popularity that suggest that discrimination may also be a factor.names, identity, discrimination
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