9,830 research outputs found
Designing transition paths for the diffusion of sustainable system innovations. A new potential role for design in transition management?
Copyright @ 2008 Umberto AllemandiIt is a shared opinion that the transition towards sustainability will be a continuous and articulated learning process, which will require radical changes on multiple levels (social, cultural, institutional and technological). It is also shared that, given the nature and the dimension of those changes, a system discontinuity is needed, and that therefore it is necessary to act on a system innovation level. The challenge now is to understand how it is possible to facilitate and support the introduction and diffusion of such innovations. Bringing together insights from both Design for sustainability and Transition management literatures, the paper puts forward a model, called Transition model of evolutionary co-design for sustainable (product-service) system innovations, aimed at facilitating and speed-up the process of designing, experimentation, niche introduction and branching of sustainable such innovations
Laser-heated thruster
The development of a computer program for the design of the thrust chamber for a CW laser heated thruster was examined. Hydrodgen was employed as the propellant gas and high temperature absorber. The laser absorption coefficient of the mixture/laser radiation combination is given in temperature and species densities. Radiative and absorptive properties are given to determine radiation from such gas mixtures. A computer code for calculating the axisymmetric channel flow of a gas mixture in chemical equilibrium, and laser energy absorption and convective and radiative heating is described. It is concluded that: (1) small amounts of cesium seed substantially increase the absorption coefficient of hydrogen; (2) cesium is a strong radiator and contributes greatly to radiation of cesium seeded hydrogen; (3) water vapor is a poor absorber; and (4) for 5.3mcm radiation, both H2O/CO and NO/CO seeded hydrogen mixtures are good absorbers
Electrostatic propulsion beam divergence effects on spacecraft surfaces, volume 3
Tests were conducted to determine the effects of electrostatic propulsion beam divergence effects on spacecraft surfaces. The subjects discussed are: (1) sensitive surfaces on the ATS 6 spacecraft, (2) the cesium ion source and testing facility, (3) cesium ion effects on thermophysical properties, and (4) simulated charge-exchange ion exposure. The compatibility of the ATS 6 ion engine experiment with the engineering subsystems and other experiments aboard the ATS 6 spacecraft was analyzed
Diverse Aging and Health Inequality by Race and Ethnicity
Although gerontologists have long embraced the concept of heterogeneity in theories and models of aging, recent research reveals the importance of racial and ethnic diversity on life course processes leading to health inequality. This article examines research on health inequality by race and ethnicity and identifies theoretical and methodological innovations that are transforming the study of health disparities. Drawing from cumulative inequality theory, we propose greater use of life course analysis, more attention to variability within racial and ethnic groups, and better integration of environmental context into the study of accumulation processes leading to health disparities
Early Phased Development of SDI as a National Insurance Policy;The Reagan Legacy and the Strategic Defense Initiative: Articles and Essays
Navigating the Updated Anaphylaxis Parameters
<p/> <p>Anaphylaxis, an acute and potentially lethal multi-system clinical syndrome resulting from the sudden, systemic degranulation of mast cells and basophils, occurs in a variety of clinical scenarios and is almost unavoidable inmedical practice. Healthcare professionalsmust be able to recognize its features, treat an episode promptly and appropriately, and be able to provide recommendations to prevent future episodes. Epinephrine, administered immediately, is the drug of choice for acute anaphylaxis. The discussion provides an overview of one set of evidence-based and consensus parameters for the diagnosis and management of anaphylaxis.</p
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