4,155 research outputs found

    Specifications for and preliminary design of a plant growth chamber for orbital experimental experiments

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    It was proposed that plant experiments be performed on board the space shuttle. To permit the proper execution of most tests, the craft must contain a plant growth chamber which is adequately designed to control those environmental factors which can induce changes in a plant's physiology and morphology. The various needs of, and environmental factors affecting, plants are identified. The permissilbe design, construction and performance limits for a plant-growth chamber are set, and tentative designs were prepared for units which are compatible with both the botanical requirements and the constraints imposed by the space shuttle

    Tables and charts of equilibrium thermodynamic properties of ammonia for temperatures from 500 to 50,000 K.

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    Equilibrium thermodynamic properties for pure ammonia were generated for a range of temperature from 500 to 50,000 K and pressure from 0.01 to 40 MN/sq m and are presented in tabulated and graphical form. Properties include pressure, temperature, density, enthalpy, speed of sound, entropy, molecular-weight ratio, specific heat at constant pressure, specific heat at constant volume, isentropic exponent, and species mole fractions. These properties were calculated by the method which is based on minimization of the Gibbs free energy. The data presented herein are for an 18-species ammonia model. Heats of formation and spectroscopic constants used as input data are presented. Comparison of several thermodynamic properties calculated with the present program and a second computer code is performed for a range of pressure and for temperatures up to 30,000 K

    Distribution of TT virus (TTV), TTV-like minivirus, and related viruses in humans and nonhuman primates

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    AbstractTT virus (TTV) and TTV-like minivirus (TLMV) are small DNA viruses with single-stranded, closed circular, antisense genomes infecting man. Despite their extreme sequence heterogeneity (>50%), a highly conserved region in the untranslated region (UTR) allows both viruses to be amplified by polymerase chain reaction (PCR). TTV/TLMV infection was detected in 88 of 100 human plasma samples; amplified sequences were differentiated into TTV and TLMV by analysis of melting profiles, showing that both viruses were similarly prevalent. PCR with UTR primers also detected frequent infection with TTV/TLMV-related viruses in a wide range of apes (chimpanzees, gorillas, orangutans, gibbons) and African monkey species (mangabeys, drills, mandrills). These findings support the hypothesis for the co-evolution of TTV-like viruses with their hosts over the period of primate speciation, potentially analogous to the evolution of primate herpesviruses

    A new paradigm for virtual knowledge sharing in product development based on emergent social software platforms

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    The UK Government considers its Aerospace Industry a remarkable success story, enjoying a global market share of 17% in 2015. The capture, management and sharing of employee knowledge is seen as vital if the industry is to remain highly innovative and retain its pre-eminent position internationally. Aerospace manufacturers, such as BAE Systems, often have to re-engineer business processes routinely to ensure their survival. Knowledge sharing in the industry is seen as challenging due to the dispersed nature of its operations and multi-tier supply chains. This article, through a 5-year participant-observation study at the Worldā€™s second largest aerospace and defence organisation, BAE Systems, proposes a new paradigm for virtual knowledge sharing in dispersed aerospace product development based on emergent social software platforms such as Enterprise 2.0 technologies. The developed framework and methodologies are applied to the bespoke BAE Systemsā€™ engineering lifecycle process to validate its effectiveness with results indicating that Enterprise 2.0 technologies offer a more openly innovative environment in which employees may share and interact with knowledge more effectively and easily across geographical and functional boundaries, compared with conventional engineering information systems

    Integrating social knowledge and collaboration tools into dispersed product development

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    Employee collaboration and knowledge sharing is vital for manufacturing organisations wishing to be successful in an ever-changing global market place; Product Development (PD) teams, in particular, rely heavily on these activities to generate innovative designs and enhancements to existing product ranges. To this end, the purpose of this paper is to present the results of a validation study carried out during an Engineering Education Scheme project to confirm the benefits of using bespoke Web 2.0-based groupware to improve collaboration and knowledge sharing between dispersed PD teams. The results of a cross-sectional survey concluded that employees would welcome greater usage of social computing technologies. The study confirmed that groupware offers the potential to deliver a more effective collaborative and knowledge sharing environment with additional communication channels on offer. Furthermore, a series of recommended guidelines are presented to show how PD teams, operating in globally-dispersed organisations, may use Web 2.0 tools to improve employee collaboration and knowledge sharing

    An Investigation into the Potential Use of Social Media Technologies to improve the Product Development Functions within the Aerospace and Defence Industry

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    Competition in global markets has resulted in increased demands for improvements in manufacturing processes. Enterprises have to re-engineer work practices and have shown that the effective communication of knowledge is fundamental to Product Development (PD). It is vital that cross-functional internal and external collaboration is optimised within PD processes and this should be facilitated through early, frequent and effective communication of information and knowledge. Social Media sites represent a new stage in the evolution of the Internet. Sites such as Facebook and Twitter, offer users the ability to stay connected online with friends and colleagues around the world in real-time; similarly, they offer the ability to locate expertise, knowledge and solutions to problems. The results of an industrial investigation, carried out within a leading aerospace and defence organisation, are commented upon and an interactive groupware solution is introduced, which aims to facilitate collaboration between dispersed product development teams

    Remote Sensing and Control of Phase Qubits

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    We demonstrate a remote sensing design of phase qubits by separating the control and readout circuits from the qubit loop. This design improves measurement reliability because the control readout chip can be fabricated using more robust materials and can be reused to test different qubit chips. Typical qubit measurements such as Rabi oscillations, spectroscopy, and excited-state energy relaxation are presented.Comment: 3 pages, 4 figure
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