6,084 research outputs found
Study of a water-vapor electrolysis unit
Sulfuric acid type water vapor electrolysis module for oxygen generation in advanced life support system
Continuous catalytic decomposition of methane
Continuous catalytic decomposition of methane and application to space life support syste
Continuous catalytic decomposition of methane
Water is conserved by employing sequence of reactions whereby 75 percent of methane from Sabatier reaction is decomposed to solid carbon and hydrogen; hydrogen is then separated from residual methane and utilized in usual Sabatier reaction to reduce remaining metabolic carbon dioxide
Farm organizations and farm profits in Tama County, Iowa
To learn in detail how farmers in Tama County, Iowa, have combined the elements of their businesses into going concerns, and the financial results which have attended their attempt to secure the most profitably organized farm, is the purpose of this study. It seeks not only to learn the anatomy or organization, but also, as far as possible, the physiology , or operation, of the farming business as found in this area. It compares the organization of these farms in 1921 with that in 1918 and in 1913. These three years, for which data have been secured, represent pre-war conditions, war-time prosperity at its height, and post-war depression at its worst. They provide a critical test for the economic principles which have been laid down for the guidance of farmers in the organization and management of their farms
LTL pricing: Looking back to the future
Numerous LTL carriers struggled during the recent recession as customers demanded lower prices. This study is designed to qualitatively evaluate the data gathered from three industry segments regarding LTL pricing. Researchers used semi-structured interviews to conduct an in-depth investigation with over two dozen industry experts who represented shippers, carriers, and 3PLs. Interview transcripts were analyzed using a grounded theory coding technique. Five major themes emerged from the interview transcripts. These themes are used to describe possible future adjustments to industry pricing structure
Post-Newtonian gravitational radiation and equations of motion via direct integration of the relaxed Einstein equations. III. Radiation reaction for binary systems with spinning bodies
Using post-Newtonian equations of motion for fluid bodies that include
radiation-reaction terms at 2.5 and 3.5 post-Newtonian (PN) order (O[(v/c)^5]
and O[(v/c)^7] beyond Newtonian order), we derive the equations of motion for
binary systems with spinning bodies. In particular we determine the effects of
radiation-reaction coupled to spin-orbit effects on the two-body equations of
motion, and on the evolution of the spins. For a suitable definition of spin,
we reproduce the standard equations of motion and spin-precession at the first
post-Newtonian order. At 3.5PN order, we determine the spin-orbit induced
reaction effects on the orbital motion, but we find that radiation damping has
no effect on either the magnitude or the direction of the spins. Using the
equations of motion, we find that the loss of total energy and total angular
momentum induced by spin-orbit effects precisely balances the radiative flux of
those quantities calculated by Kidder et al. The equations of motion may be
useful for evolving inspiraling orbits of compact spinning binaries.Comment: 19 pages, small corrections, equivalent to published versio
Hemochromatosis (HFE) gene variants are associated with increased mitochondrial DNA levels during HIV-1 infection and antiretroviral therapy
The Need to Feed Homeostatic and Hedonic Control of Eating
AbstractFeeding provides substrate for energy metabolism, which is vital to the survival of every living animal and therefore is subject to intense regulation by brain homeostatic and hedonic systems. Over the last decade, our understanding of the circuits and molecules involved in this process has changed dramatically, in large part due to the availability of animal models with genetic lesions. In this review, we examine the role played in homeostatic regulation of feeding by systemic mediators such as leptin and ghrelin, which act on brain systems utilizing neuropeptide Y, agouti-related peptide, melanocortins, orexins, and melanin concentrating hormone, among other mediators. We also examine the mechanisms for taste and reward systems that provide food with its intrinsically reinforcing properties and explore the links between the homeostatic and hedonic systems that ensure intake of adequate nutrition
Magnetohydrodynamics of Cloud Collisions in a Multi-phase Interstellar Medium
We extend previous studies of the physics of interstellar cloud collisions by
beginning investigation of the role of magnetic fields through 2D
magnetohydrodynamic (MHD) numerical simulations. We study head-on collisions
between equal mass, mildly supersonic diffuse clouds. We include a moderate
magnetic field and two limiting field geometries, with the field lines parallel
(aligned) and perpendicular (transverse) to the colliding cloud motion. We
explore both adiabatic and radiative cases, as well as symmetric and asymmetric
ones. We also compute collisions between clouds evolved through prior motion in
the intercloud medium and compare with unevolved cases.
We find that: In the (i) aligned case, adiabatic collisions, like their HD
counterparts, are very disruptive, independent of the cloud symmetry. However,
when radiative processes are taken into account, partial coalescence takes
place even in the asymmetric case, unlike the HD calculations. In the (ii)
transverse case, collisions between initially adjacent unevolved clouds are
almost unaffected by magnetic fields. However, the interaction with the
magnetized intercloud gas during the pre-collision evolution produces a region
of very high magnetic energy in front of the cloud. In collisions between
evolved clouds with transverse field geometry, this region acts like a
``bumper'', preventing direct contact between the clouds, and eventually
reverses their motion. The ``elasticity'', defined as the ratio of the final to
the initial kinetic energy of each cloud, is about 0.5-0.6 in the cases we
considered. This behavior is found both in adiabatic and radiative cases.Comment: 40 pages in AAS LaTeX v4.0, 13 figures (in degraded jpeg format).
Full resolution images as well as mpeg animations are available at
http://www.msi.umn.edu:80/Projects/twj/mhd-cc/ . Accepted for publication in
The Astrophysical Journa
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