A review of nonequilibrium effects and surface catalysis on shuttle heating

A review is given of the nonequilibrium calculation techniques by various authors over the past decade to predict heat fluxes to the windward side of the Space Shuttle orbiter. The results of these techniques are compared with measurements made on the first few flights of the Space Shuttle. The calculations attempt to account for finite rate chemistry in the shock layer around the vehicle and for finite rate catalytic atom recombination on the thermal protection materials. The techniques considered are the axisymmetric viscous shock layer method, three dimensional reacting Euler equation solutions coupled with axisymmetric analog boundary layer method, and a recently developed nonequilibrium 3-D viscous shock layer method

Engaging the Digitally Engaged Student: Comparing Technology-Mediated Communication Use and Effects on Student Learning

The role of communication technologies in the learning process is both a dynamic and complex issue. Yet, we know surprisingly little about how the use of specific communication technologies may influence classroom performance, key learning outcomes, and other measures of course satisfaction. The research reported here attempts to add to our knowledge about the role of communication in the technology enhanced classroom (TEC) education and in technology-enhanced online (TEO) education through a direct comparison of two courses. Our findings indicate additional support for “The No Significant Difference Phenomenon.” Furthermore, we found that prior experiences lead students to gravitate towards their preferred learning environments, and that basic website elements are required in any learning environment to enhance student outcomes. Finally, we found that when used appropriately, the benefits of communication technology use in education outweigh many of the drawbacks

Whoʼs Watching Us at Work? Toward a Structural-Perceptual Model of Electronic Monitoring and Surveillance in Organizations

Nearly 80% of organizations now employ some form of employee surveillance. This significant level of use infers a salient need for additional theory and research into the effects of monitoring and surveillance. Accordingly, this essay examines the panoptic effects of electronic monitoring and surveillance (EM/S) of social communication in the workplace and the underlying structural and perceptual elements that lead to these effects. It also provides future scholarly perspectives for studying EM/S and privacy in the organization from the vantage point of contemporary communication technologies, such as the telephone, voice mail, e-mail, and instant messaging, utilized for organizational communication. Finally, four propositions are presented in conjunction with a new communication-based model of EM/S, providing a framework incorporating three key components of the panoptic effect: (a) communication technology use, (b) organizational factors, and (c) organizational policies for EM/S

Towards the Final Frontier: Using Strategic Communication Activities to Engage the Latent Public as a Key Stakeholder in a Corporate Mission

Private corporations that do not normally interact with, nor regularly communicate with, the public often do not perceive the public as a relevant or active stakeholder. The public may not view themselves as a stakeholder, particularly when they are unaware of, have no direct dealings with, or do not have any problems associated with such a corporation. The current study, utilizing a national survey of the United States public (N = 424) found that through directed strategic communication activities of a private spaceflight corporation, utilizing social and new media tools, a latent public can perceive a corporation and its mission in a positive manner, and transition it towards a status of an aware public and possible active public. Positive perceptions were found regarding corporate credibility, brand awareness, public engagement, communicating a corporate mission, educating the public, and influencing public opinion

Wall boundary equations with slip and catalysis for multicomponent, nonequilibrium gas flows

Boundary equations obtained for a low Reynolds number, high enthalpy gas flow in regions of velocity slip and temperature jump are presented. The formulation treats, through a first-order distribution function used to include multicomponent diffusion, a multicomponent gas mixture that may be in nonequilibrium with finite-rate catalytic recombination occurring on the wall. In the boundary equations, which are obtained for use in flow-field calculations applicable to low-density flow regimes, a simplified gas/wall interaction is assumed wherein individual atoms or molecules either reflect specularly off the wall or stick and are fully accommodated. Fluxes in terms of evaluated integrals over the distribution function and integrals necessary for determining fluxes are given

Measured catalycities of various candidate space shuttle thermal protection system coatings at low temperatures

Atom recombination catalytic rates for surface coatings of various candidate thermal protection system materials for the space shuttle vehicle were obtained from measurements in arc jet, air flow. The coatings, chrome oxides, siliconized carbon/carbon, hafnium/tantalum carbide on carbon/carbon, and niobium silicide, were bonded to the sensitive surface of transient slug calorimeters that measured the heat transfer rates to the coatings. The catalytic rates were inferred from these heat transfer rates Surface temperatures of the calorimeters varied from approximately 300 to 410 K

p-topological and p-regular: dual notions in convergence theory

The natural duality between "topological" and "regular," both considered as convergence space properties, extends naturally to p-regular convergence spaces, resulting in the new concept of a p-topological convergence space. Taking advantage of this duality, the behavior of p-topological and p-regular convergence spaces is explored, with particular emphasis on the former, since they have not been previously studied. Their study leads to the new notion of a neighborhood operator for filters, which in turn leads to an especially simple characterization of a topology in terms of convergence criteria. Applications include the topological and regularity series of a convergence space.Comment: 12 pages in Acrobat 3.0 PDF forma

Getting on the E List: E-Mail Use in a Community of Service Provider

This case examines how a community of organizations providing service to people experiencing homelessness made use of an electronic mail list. Current economic conditions have encouraged organizations in various sectors—including nonprofits—that might normally compete for scarce resources to collaborate with one another to increase their chances of survival. One set of tools likely to be of value in such relationships includes various online discussion technologies. An examination of this community’s email list use over a three-year period suggests a somewhat complex picture regarding technology use. More specifically, some issues both constrain and enable use. Additionally, seemingly basic and minimal uses of the list provided not only the greatest functionality for the users, but also led to several unanticipated consequences for those involved

Impacts of Urbanization on Base Flow and Recharge Rates, Northeastern Illinois: Summary of Year 1 Activities

During year one of a two-year project to investigate the impacts of urbanization on base flow and ground-water recharge rates in northeastern Illinois, three gaged watersheds in urbanized areas of northeastern Illinois, and one watershed located in rural northwestern Illinois, have been selected for study. The gages have a common period of record extending from October 1952 through the present, a period during which the northeastern Illinois watersheds underwent substantial urbanization. Mean daily discharge data from the gages have been analyzed using an automated hydrograph separation technique, and monthly estimates of mean total discharge, base flow, and direct runoff have been calculated. Spearman rank correlation coefficients indicate a stronger correlation between precipitation and total discharge, base flow, and direct runoff in the northeastern Illinois watersheds than in the rural watershed. Smoothed time-series plots of total discharge, base flow, and direct runoff in the urban watersheds are less consistent with precipitation than similar plots constructed from the rural watershed data. The trends indicate that rates of direct runoff have overtaken rates of base flow in two of the three northeastern Illinois watersheds, but in one of these watersheds, this relationship probably reflects the cessation of effluent discharges to the stream. In general, double-mass curve analysis suggests that, relative to the rural watershed, base flow in the urban watersheds has proportionally decreased, and direct runoff has proportionally increased. The trends suggested by the smoothed time-series plots and the double-mass curves are consistent with a conceptual model of the northeastern Illinois watersheds in which sewering and impervious surfaces have reduced infiltration, and thence ground-water recharge and base flow, in the watersheds.Ope