2,923 research outputs found
Quality requirements for reclaimed/recycled water
Water used during current and previous space missions has been either carried or made aloft. Future human space endeavors will require some form of water reclamation and recycling. There is little experience in the U.S. space program with this technology. Water reclamation and recycling constitute engineering challenges of the broadest nature that will require an intensive research and development effort if this technology is to mature in time for practical use on the proposed U.S. Space Station. In order for this to happen, reclaimed/recycled water specifications will need to be devised to guide engineering development. Present NASA Potable Water Specifications are not applicable to reclaimed or recycled water. Adequate specifications for ensuring the quality of the reclaimed or recycled potable water system is reviewed, limitations of present water specifications are examined, world experience with potable water reclamation/recycling systems and systems analogs is reviewed, and an approach to developing pertinent biomedical water specifications for spacecraft is presented. Space Station water specifications should be designed to ensure the health of all likely spacecraft inhabitants including man, animals, and plants
Renormalization Group Study of the Intrinsic Finite Size Effect in 2D Superconductors
Vortices in a thin-film superconductor interact logarithmically out to a
distance on the order of the two-dimensional (2D) magnetic penetration depth
, at which point the interaction approaches a constant. Thus,
because of the finite , the system exhibits what amounts to an
{\it intrinsic} finite size effect. It is not described by the 2D Coulomb gas
but rather by the 2D Yukawa gas (2DYG). To study the critical behavior of the
2DYG, we map the 2DYG to the massive sine-Gordon model and then perform a
renormalization group study to derive the recursion relations and to verify
that is a relevant parameter. We solve the recursion relations
to study important physical quantities for this system including the
renormalized stiffness constant and the correlation length. We also address the
effect of current on this system to explain why finite size effects are not
more prevalent in experiments given that the 2D magnetic penetration depth is a
relevant parameter.Comment: 8 pages inRevTex, 5 embedded EPS figure
The Current-Temperature Phase Diagram of Layered Superconductors
The behavior of clean layered superconductors in the presence of a finite
electric current and in zero-magnetic field behavior is addressed. The
structure of the current temperature phase diagram and the properties of each
of the four regions will be explained. We will discuss the expected current
voltage and resistance characteristics of each region as well as the effects of
finite size and weak disorder on the phase diagram. In addition, the reason for
which a weakly non-ohmic region exists above the transition temperature will be
explained.Comment: 8 pages (RevTeX), 4 encapsulated postscript figure
Evaluation of Foliar Fungicides and Insecticides on Soybeans in Central Iowa
Iowa State University personnel assessed foliar fungicides and insecticide use on soybeans at seven locations across Iowa including the Northwest Farm (Sutherland), Northern Farm (Kanawha), Northeast Farm (Nashua), Curtiss Farm (Ames), Armstrong Farm (Lewis), McNay Farm (Chariton), and Southeast Farm (Crawfordsville) (Figure 1)
Intake of Fish and Omega-3 (n-3) Fatty Acids: Effect on Humans During Actual and Simulated Weightlessness
Space flight has many negative effects on human physiology, including bone and muscle loss. Bone and muscle are two systems that are positively affected by dietary intake of fish and n-3 fatty acids. The mechanism is likely to be related to inhibition by n-3 fatty acids of inflammatory cytokines (such as TNF) and thus inhibition of downstream NF-kB activation. We have documented this effect in a 3-dimensional cell culture model, where NF-kB activation in osteoclasts was inhibited by eicosapentaenoic acid, an n-3 fatty acid. We have also indentified that NF-kB activation in peripheral blood mononuclear cells of Space Shuttle crews. We found that after Shuttle flights of ~2 wk, expression of the protein p65 (evidence of NF-kB activation) was increased at landing (P less than 0.001). When evaluating the effects of n-3 fatty acid intake on bone breakdown after 60 d of bed rest (a weightlessness analog). We found that after 60 d of bed rest, greater intake of n-3 fatty acids was associated with less N-telopeptide excretion (Pearson r = -0.62, P less than 0.05). We also evaluated the relationship of fish intake and bone loss in astronauts after 4 to 6 mo missions on the International Space Station. Higher consumption of fish during flight was associated with higher bone mineral density (Pearson r = 0.46, P less than 0.05). Together, these findings provide evidence of the cellular mechanism by which n-3 fatty acids can inhibit bone loss, and preliminary human evidence of the potential for n-3 fatty acids to counteract bone loss associated with space flight. This study was supported by the NASA Human Research Program
Evaluation of Foliar Fungicides and Insecticides on Soybeans in Northern Iowa
Iowa State University personnel assessed foliar fungicides and insecticide use on soybeans at seven locations across Iowa including the Northwest Farm (Sutherland), Northern Farm (Kanawha), Northeast Farm (Nashua), Curtiss Farm (Ames), Armstrong Farm (Lewis), McNay Farm (Chariton), and Southeast Farm (Crawfordsville)
Evaluation of Foliar Fungicides and Insecticides on Soybeans in Northwest Iowa
Iowa State University personnel assessed foliar fungicides and insecticide use on soybeans at seven locations across Iowa including the Northwest Farm (Sutherland), Northern Farm (Kanawha), Northeast Farm (Nashua), Curtiss Farm (Ames), Armstrong Farm (Lewis), McNay Farm (Chariton), and Southeast Farm (Crawfordsville)
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