50,491 research outputs found
Determination of a Definition of Solar Grade Silicon
A definition of solar grade silicon was determined by investigating the singular and the combined effect of the impurities usually found in metallurgical grade silicon on solar cell device performance. The impurity matrix was defined by Jet Propulsion Laboratory Technical Direction Memorandum. The initial work was focussed on standardizing the solar cell process and test procedure, growing baseline crystals, growing crystals contaminated with carbon, iron, nickel, zirconium, aluminum and vanadium, solar blank preparation, and material characterization
A monostrain test apparatus
Test apparatus is designed for determining tensile strength, modulus of elasticity, elongation, and thermal coefficient of contraction or expansion of uniformly shaped plastics, adhesives, and foam materials over temperature range of 700 to 90 K (800 to -300). Tests may be used in design quality control, and in evaluation of new adhesives and plastic materials
The cell cycle program of polypeptide labeling in Chlamydomonas reinhardtii
The cell cycle program of polypeptide labeling in syndhronous cultures of wild-type Chlamydomonas reinhardtii was analyzed by pulse-labeling cells with 35SO4 = or [3H]arginine at different cell cycle stages. Nearly 100 labeled membrane and soluble polypeptides were resolved and studied using one-dimensional sodium dodecyl sulfate (SDS)- polyacrylamide gel electrophoresis. The labeling experiments produced the following results. (a) Total 35SO4 = and [3H]arginine incorporation rates varied independently throughout the cell cycle. 35SO4 = incorporation was highest in the mid-light phase, while [3H]arginine incorporation peaked in the dark phase just before cell division. (b) The relative labeling rate for 20 of 100 polypeptides showed significant fluctuations (3-12 fold) during the cell cycle. The remaining polypeptides were labeled at a rate commensurate with total 35SO4 = or [3H]arginine incorporation. The polypeptides that showed significant fluctuations in relative labeling rates served as markers to identify cell cycle stages. (c) The effects of illumination conditions on the apparent cell cycle stage-specific labeling of polypeptides were tested. Shifting light-grown asynchronous cells to the dark had an immediate and pronounced effect on the pattern of polypeptide labeling, but shifting dark-phase syndhronous cells to the light had little effect. The apparent cell cycle variations in the labeling of ribulose 1,5-biphosphate (RUBP)-carboxylase were strongly influenced by illumination effects. (d) Pulse-chase experiments with light-grown asynchronous cells revealed little turnover or inter- conversion of labeled polypeptides within one cell generation, meaning that major polypeptides, whether labeled in a stage-specific manner or not, do not appear transiently in the cell cycle of actively dividing, light-grown cells. The cell cycle program of labeling was used to analyze effects of a temperature-sensitive cycle blocked (cb) mutant. A synchronous culture of ts10001 was shifted to restrictive temperature before its block point to prevent it from dividing. The mutant continued its cell cycle program of polypeptide labeling for over a cell generation, despite its inability to divide
Solar-cycle variation of the sound-speed asphericity from GONG and MDI data 1995-2000
We study the variation of the frequency splitting coefficients describing the
solar asphericity in both GONG and MDI data, and use these data to investigate
temporal sound-speed variations as a function of both depth and latitude during
the period from 1995-2000 and a little beyond. The temporal variations in even
splitting coefficients are found to be correlated to the corresponding
component of magnetic flux at the solar surface. We confirm that the
sound-speed variations associated with the surface magnetic field are
superficial. Temporally averaged results show a significant excess in sound
speed around 0.92 solar radii and latitude of 60 degrees.Comment: To be published in MNRAS, accepted July 200
Social cost considerations and legal constraints in implementing modular integrated utility systems
Social costs associated with the design, demonstration, and implementation of the Modular Integrated Utility System are considered including the social climate of communities, leadership patterns, conflicts and cleavages, specific developmental values, MIUS utility goal assessment, and the suitability of certian alternative options for use in a program of implementation. General considerations are discussed in the field of socio-technological planning. These include guidelines for understanding the conflict and diversity; some relevant goal choices and ideas useful to planners of the MIUS facility
Testing the Validity of Standard Representative Agent Import Demand Systems
Demand and Price Analysis, International Relations/Trade,
Relationship between Thermodynamic Driving Force and One-Way Fluxes in Reversible Chemical Reactions
Chemical reaction systems operating in nonequilibrium open-system states
arise in a great number of contexts, including the study of living organisms,
in which chemical reactions, in general, are far from equilibrium. Here we
introduce a theorem that relates forward and re-verse fluxes and free energy
for any chemical process operating in a steady state. This rela-tionship, which
is a generalization of equilibrium conditions to the case of a chemical process
occurring in a nonequilibrium steady state, provides a novel equivalent
definition for chemical reaction free energy. In addition, it is shown that
previously unrelated theories introduced by Ussing and Hodgkin and Huxley for
transport of ions across membranes, Hill for catalytic cycle fluxes, and Crooks
for entropy production in microscopically reversible systems, are united in a
common framework based on this relationship.Comment: 11 page
Metallic multilayers for X-band Bragg reflector applications
We present a structural and high frequency (8.72GHz) electrical characterization of sputter deposited Ti/W, Ti/Ru and Mo/Ti metallic multilayers for potential application as acoustic Bragg reflectors. We prove that all metallic multilayers comprised of different acoustic impedance metals such as Ti, W, Mo are promising candidates for Bragg reflector/bottom electrode in full X-band thin film acoustic resonators. Values for high frequency resistivity of the order of are measured by use of a contact-free/non-invasive sheet resistance method
Sprayable low density ablator and application process
A sprayable, low density ablative composition is described consisting esentially of: (1) 100 parts by weight of a mixture of 25-65% by weight of phenolic microballoons, 0-20% by weight of glass microballoons, 4-10% by weight of glass fibers, 25-45% by weight of an epoxy-modified polyurethane resin, 2-4% by weight of a bentonite dispersing aid, and 1-2% by weight of an alcohol activator for the bentonite; (2) 1-10 parts by weight of an aromatic amine curing agent; and (3) 200-400 parts by weight of a solvent
Exceptional accumulation and retention of dimethylsulfoniopropionate by molluscs
Author Posting. © The Author(s), 2015. This is the author's version of the work. It is posted here by permission of CSIRO Publishing for personal use, not for redistribution. The definitive version was published in Environmental Chemistry 13 (2016): 231-238, doi:10.1071/EN14267.Molluscs often play major roles in processing phytoplankton-synthesized dimethylsulfoniopropionate (DMSP) in local ecosystems. We find that some mollusc species retain tissue DMSP exceptionally tightly and exhibit unusually great and statistically nonnormal interindividual variation in DMSP accumulation and retention. Individual mussels (Mytilus, Geukensia) living within a single clump, for example, range 6- to 11-fold in tissue [DMSP] and are often nonnormal in statistical distribution. These properties cannot be explained by the elevation of the substrate on which the mussels are living or by mussel position in a clump. When mussels (M. edulis) are deprived of DMSP for up to 5 weeks in depuration experiments, some individuals retain high tissue [DMSP], whereas others exhibit reduced [DMSP]. Such interindividual divergence helps explain nonnormal distributions of tissue [DMSP] after depuration. We re-analyze published data from which the half-time for tissue DMSP loss during depuration can be calculated. In the only mollusc so studied (Haliotis), the half-time is 13-25 times longer than in similar-size fish. Besides posing a challenge for DMSP mass balance studies, retention and interindividual variation may point to as yet unknown properties of molluscs: Tight retention suggests functional roles for DMSP, and nonnormal statistical distributions suggest discontinuities among individuals in DMSP metabolism
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