499 research outputs found

    Control of static electricity in 35mm film transports under vacuum conditions

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    Control of static electricity in transporting 35mm film in vacuu

    Tether applications for space station

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    A wide variety of space station applications for tethers were reviewed. Many will affect the operation of the station itself while others are in the category of research or scientific platforms. One of the most expensive aspects of operating the space station will be the continuing shuttle traffic to transport logistic supplies and payloads to the space station. If a means can be found to use tethers to improve the efficiency of that transportation operation, it will increase the operating efficiency of the system and reduce the overall cost of the space station. The concept studied consists of using a tether to lower the shuttle from the space station. This results in a transfer of angular momentum and energy from the orbiter to the space station. The consequences of this transfer is studied and how beneficial use can be made of it

    Rocket studies of solar corona and transition region

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    The XSST (X-Ray Spectrometer/Spectrograph Telescope) rocket payload launched by a Nike Boosted Black Brant was designed to provide high spectral resolution coronal soft X-ray line information on a spectrographic plate, as well as time resolved photo-electric records of pre-selected lines and spectral regions. This spectral data is obtained from a 1 x 10 arc second solar region defined by the paraboloidal telescope of the XSST. The transition region camera provided full disc images in selected spectral intervals originating in lower temperature zones than the emitting regions accessible to the XSST. A H-alpha camera system allowed referencing the measurements to the chromospheric temperatures and altitudes. Payload flight and recovery information is provided along with X-ray photoelectric and UV flight data, transition camera results and a summary of the anomalies encountered. Instrument mechanical stability and spectrometer pointing direction are also examined

    Pan African Humanness and Sakhu Djaer as Praxis for Indigenous Knowledge Systems

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    This paper will explore the notion of Sakhu Djaer (Skh Djr) as a further refinement and deeper extension of Black Psychology’s African essence. Through an exposition of the thinking and beliefs about African knowing and being, the discussion will further unpack the necessary link between UbuNtu, African language and logic, epistemic justice, and indigenous knowledge systems as central to an understanding of African existence and being. In representing a requisite paradigm shift from Eurocentric to African-centred analyses, this discussion will demonstrate the adoption of African notions of Pan African Humanness, indigenous knowledge systems and terminology (Sumunu, Kizungu Zongu, etc.) as key to the illumination and reframing of a Pan African therapeutic engagement and the teaching and training of psychologists in the African worldview, ontology and culture

    Feasibility study of the solar scientific instruments for Spacelab/Orbiter

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    The feasibility and economics of mounting and operating a set of solar scientific instruments in the backup Skylab Apollo Telescope Mount (ATM) hardware was evaluated. The instruments used as the study test payload and integrated into the ATM were: the Solar EUV Telescope/Spectrometer; the Solar Active Region Observing Telescope; and the Lyman Alpha White Light Coronagraph. The backup ATM hardware consists of a central cruciform structure, called the "SPAR', a "Sun End Canister' and a "Multiple Docking Adapter End Canister'. Basically, the ATM hardware and software provides a structural interface for the instruments; a closely controlled thermal environment; and a very accurate attitude and pointing control capability. The hardware is an identical set to the hardware that flow on Skylab

    Multidimensional Model of Racial Identity: A Reconceptualization of African American Racial Identity

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    Research on African American racial identity has utilized 2 distinct approaches. The mainstream approach has focused on universal properties associated with ethnic and racial identities. In contrast, the underground approach has focused on documenting the qualitative meaning of being African American, with an emphasis on the unique cultural and historical experiences of African Americans. The Multidimensional Model of Racial Identity (MMRI) represents a synthesis of the strengths of these two approaches. The underlying assumptions associated with the model are explored. The model proposes 4 dimensions of African American racial identity: salience, centrality, regard, and ideology. A description of these dimensions is provided along with a discussion of how they interact to influence behavior at the level of the event. We argue that the MMRI has the potential to make contributions to traditional research objectives of both approaches, as well as to provide the impetus to explore new questions.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68695/2/10.1207_s15327957pspr0201_2.pd

    What About my Privacy, Habibi? Understanding Privacy Concerns and Perceptions of Users From Different Socioeconomic Groups in the Arab World

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    This paper contributes an in-depth understanding of privacy concerns and perceptions of Arab users. We report on the first comparison of privacy perceptions among (1) users from high socioeconomic groups in Arab countries (HSA), (2) users from medium to low socioeconomic groups in Arab countries (LSA), and (3) as a baseline, users from high socioeconomic groups in Germany (HSG). Our work is motivated by the fact that most research in privacy focused on Western, Educated, Industrialized, Rich, and Democratic (WEIRD) societies. This excludes a segment of the population whose cultural norms and socioeconomic status influence privacy perception and needs. We report on multiple novel findings and unexpected similarities and differences across the user groups. For example, shoulder surfing is more common across LSA and HSG, and defamation is a major threat in LSA. We discuss the implications of our findings on the design of privacy protection measures for investigated groups

    The preparation of graft copolymers of cellulose and cellulose derivatives using ATRP under homogeneous reaction conditions

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    In this comprehensive review, we report on the preparation of graft-copolymers of cellulose and cellulose derivatives using atom transfer radical polymerization (ATRP) under homogeneous conditions. The review is divided into four sections according to the cellulosic material that is graft-copolymerised; (i) cellulose, (ii) ethyl cellulose, (iii) hydroxypropyl cellulose and (iv) other cellulose derivatives. In each section, the grafted synthetic polymers are described as well as the methods used for ATRP macro-initiator formation and graft-copolymerisation. The physical properties of the graft-copolymers including their self-assembly in solution into nanostructures and their stimuli responsive behaviour are described. Potential applications of the self-assembled graft copolymers in areas such as nanocontainers for drug delivery are outline

    Human Pathogen Shown to Cause Disease in the Threatened Eklhorn Coral Acropora palmata

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    Coral reefs are in severe decline. Infections by the human pathogen Serratia marcescens have contributed to precipitous losses in the common Caribbean elkhorn coral, Acropora palmata, culminating in its listing under the United States Endangered Species Act. During a 2003 outbreak of this coral disease, called acroporid serratiosis (APS), a unique strain of the pathogen, Serratia marcescens strain PDR60, was identified from diseased A. palmata, human wastewater, the non-host coral Siderastrea siderea and the corallivorous snail Coralliophila abbreviata. In order to examine humans as a source and other marine invertebrates as vectors and/or reservoirs of the APS pathogen, challenge experiments were conducted with A. palmata maintained in closed aquaria to determine infectivity of strain PDR60 from reef and wastewater sources. Strain PDR60 from wastewater and diseased A. palmata caused disease signs in elkhorn coral in as little as four and five days, respectively, demonstrating that wastewater is a definitive source of APS and identifying human strain PDR60 as a coral pathogen through fulfillment of Koch's postulates. A. palmata inoculated with strain PDR60 from C. abbreviata showed limited virulence, with one of three inoculated fragments developing APS signs within 13 days. Strain PDR60 from non-host coral S. siderea showed a delayed pathogenic effect, with disease signs developing within an average of 20 days. These results suggest that C. abbreviata and non-host corals may function as reservoirs or vectors of the APS pathogen. Our results provide the first example of a marine “reverse zoonosis” involving the transmission of a human pathogen (S. marcescens) to a marine invertebrate (A. palmata). These findings underscore the interaction between public health practices and environmental health indices such as coral reef survival
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