Operational modules for space station construction

Identification of an effective space construction concept is a current objective of NASA studies. One concept, described in this memorandum, consists of repetitive use of operational modules, which minimizes on-orbit stay time for the shuttle. A space station constructed of operational modules may benefit from fabrication and system checkout in ground-based facilities, and since the modules are the primary structure of the space station, a minimum of additional structure, and trips and on-orbit stay time of the shuttle are required

Joint design for improved fatigue life of diffusion-bonded box-stiffened panels

Simple photoelastic models were used to identify a cross-section geometry that would eliminate the severe stress concentrations at the bond line between box stiffeners diffusion bonded to a panel skin. Experimental fatigue-test data from titanium test specimens quantified the allowable stress in terms of cycle life for various joint geometries. It is shown that the effect of stress concentration is reduced and an acceptable fatigue life is achieved

Four Phases Quality Function Deployment (QFD) by Considering Kano Concept, TIME and Manufacturing Cost

Each company must carry out product development to maintain or build sales. Relationship between specifications and parameters of quality products to the wishes of the customer is an important consideration in doing product development. Product development methods QFD (Quality Function Deployment) has been widely applied in industry to maximize customer satisfaction based on quality, cost, time and other, become source of constraints. Quality, time and cost are important factors for a company to maintain existency of the company in the industry. This study will provide customer deployment requirements to consider not only the quality factors are more often a point of view assuming the successful development of a product, but also on the factors of time and cost. Factors to be considered in stages creating new products or improving old products are not only detailed data about the four phases of phasing as product planning, product design, process planning, process control and planning is needed, but also a complete view of the overall technical response . The final integration of the four phases of QFD is influential in producing and marketing the products. Team of product development must plan how to design new products to exploit existing technical response. Matters relating to the quality characteristic and the voice of stakeholders is very relevant and should be well understood and thoroughly. Technical approach to a more detailed response can lead a team of product developers to pay attention to the changes of each phase to obtain the allocation of resources for each of the responses are perfectly

Temperature dependence of the interlayer magnetoresistance of quasi-one-dimensional Fermi liquids at the magic angles

The interlayer magnetoresistance of a quasi-one-dimensional Fermi liquid is considered for the case of a magnetic field that is rotated within the plane perpendicular to the most-conducting direction. Within semi-classical transport theory dips in the magnetoresistance occur at integer amgic angles only when the electronic dispersion parallel to the chains is nonlinear. If the field direction is fixed at one of the magic angles and the temperature is varied the resulting variation of the scattering rate can lead to a non-monotonic variation of the interlayer magnetoresistance with temperature. Although the model considered here gives a good description of some of the properties of the Bechgaard salts, (TMTSF)2PF6 for pressures less than 8kbar and (TMTSF)2ClO4 it gives a poor description of their properties when the field is parallel to the layers and of the intralayer transport.Comment: 10pages, RevTeX + epsf, 3 figure

Visualizing atomic-scale redox dynamics in vanadium oxide-based catalysts

Surface redox processes involving oxygen atom exchange are fundamental in catalytic reactions mediated by metal oxides. These processes are often difficult to uncover due to changes in the surface stoichiometry and atomic arrangement. Here we employ high-resolution transmission electron microscopy to study vanadium oxide supported on titanium dioxide, which is of relevance as a catalyst in, e.g., nitrogen oxide emission abatement for environmental protection. The observations reveal a reversible transformation of the vanadium oxide surface between an ordered and disordered state, concomitant with a reversible change in the vanadium oxidation state, when alternating between oxidizing and reducing conditions. The transformation depends on the anatase titanium dioxide surface termination and the vanadium oxide layer thickness, suggesting that the properties of vanadium oxide are sensitive to the supporting oxide. These atomic-resolution observations offer a basis for rationalizing previous reports on shape-sensitive catalytic properties

Motive8!: feasibility of a text messaging intervention to promote physical activity in knee osteoarthritis

Aim: To develop and test the feasibility of using a SMS text messaging intervention to promote physical activity in patients with knee OA. Methods: 27 people (6 male, 21 female; aged 25-81 years) with knee osteoarthritis received 4 text messages per week, for 6 weeks. Telephone surveys were conducted at baseline and 6 weeks to measure physical activity levels and beliefs, including self-efficacy for exercise, barriers and benefits of exercise, social support and pain. Participants completed physical activity diaries. Process evaluation included participant perceptions of the intervention and 'real-time' data on intervention fidelity (automated collection of delivery and response data) and participant engagement (text response). Results: 648 messages were sent, 100% were accurately delivered. From baseline to 6 weeks, physical activity, self-efficacy for exercise, perceived benefits of exercise and social support significantly increased; reductions were observed in barriers to exercise and pain. Participants engaged with the intervention; 100% read the messages, 89% responded to texts requesting replies, 64% completed physical activity diaries with low attenuation (1.8% drop) by six weeks. Participants perceived messaging to be enjoyable (96%), personally relevant (85%), of appropriate frequency (100%) and duration (88%). Mobile phones, email and web were perceived to be most acceptable for health promotion compared with other forms of technology. Conclusions: People with knee osteoarthritis can engage meaningfully with an interactive mobile phone messaging intervention over a six-week period. Health communications promoting physical activity demonstrate potential for behaviour change and positive implications for perceptions of exercise and pain; this needs to be tested in a randomised trial. Data collected in 'real-time' can be used for process evaluation to demonstrate participant engagement and intervention fidelity

Influence of Homeotropic Anchoring Walls upon Nematic and Smectic Phases

McMillan liquid crystal model sandwiched between strong homeotropic anchoring walls is studied. Phase transitions between isotropic, nematic, and smectic A phases are investigated for wide ranges of an interaction parameter and of the system thickness. It is confirmed that the anchoring walls induce an increase in transition temperatures, dissappearance of phase transitions, and an appearance of non-spontaneous nematic phase. The similarity between influence of anchoring walls and that of external fields is discussed.Comment: 5 pages, 6 figure

Rhomboid homologs in mycobacteria: insights from phylogeny and genomic analysis

<p>Abstract</p> <p>Background</p> <p>Rhomboids are ubiquitous proteins with diverse functions in all life kingdoms, and are emerging as important factors in the biology of some pathogenic apicomplexa and <it>Providencia stuartii</it>. Although prokaryotic genomes contain one rhomboid, actinobacteria can have two or more copies whose sequences have not been analyzed for the presence putative rhomboid catalytic signatures. We report detailed phylogenetic and genomic analyses devoted to prokaryotic rhomboids of an important genus, <it>Mycobacterium</it>.</p> <p>Results</p> <p>Many mycobacterial genomes contained two phylogenetically distinct active rhomboids orthologous to Rv0110 (rhomboid protease 1) and Rv1337 (rhomboid protease 2) of <it>Mycobacterium tuberculosis </it>H37Rv, which were acquired independently. There was a genome-wide conservation and organization of the orthologs of Rv1337 arranged in proximity with glutamate racemase (<it>mur1</it>), while the orthologs of Rv0110 appeared evolutionary unstable and were lost in <it>Mycobacterium leprae </it>and the <it>Mycobacterium avium </it>complex. The orthologs of Rv0110 clustered with eukaryotic rhomboids and contained eukaryotic motifs, suggesting a possible common lineage. A novel nonsense mutation at the Trp73 codon split the rhomboid of <it>Mycobacterium avium </it>subsp. <it>Paratuberculosis </it>into two hypothetical proteins (MAP2425c and MAP2426c) that are identical to MAV_1554 of <it>Mycobacterium avium</it>. Mycobacterial rhomboids contain putative rhomboid catalytic signatures, with the protease active site stabilized by Phenylalanine. The topology and transmembrane helices of the Rv0110 orthologs were similar to those of eukaryotic secretase rhomboids, while those of Rv1337 orthologs were unique. Transcription assays indicated that both mycobacterial rhomboids are possibly expressed.</p> <p>Conclusions</p> <p>Mycobacterial rhomboids are active rhomboid proteases with different evolutionary history. The Rv0110 (rhomboid protease 1) orthologs represent prokaryotic rhomboids whose progenitor may be the ancestors of eukaryotic rhomboids. The Rv1337 (rhomboid protease 2) orthologs appear more stable and are conserved nearly in all mycobacteria, possibly alluding to their importance in mycobacteria. MAP2425c and MAP2426c provide the first evidence for a split homologous rhomboid, contrasting whole orthologs of genetically related species. Although valuable insights to the roles of rhomboids are provided, the data herein only lays a foundation for future investigations for the roles of rhomboids in mycobacteria.</p