Effects of anisotropic conduction and heat pipe interaction on minimum mass space radiators

Equations are formulated for the two dimensional, anisotropic conduction of heat in space radiator fins. The transverse temperature field was obtained by the integral method, and the axial field by numerical integration. A shape factor, defined for the axial boundary condition, simplifies the analysis and renders the results applicable to general heat pipe/conduction fin interface designs. The thermal results are summarized in terms of the fin efficiency, a radiation/axial conductance number, and a transverse conductance surface Biot number. These relations, together with those for mass distribution between fins and heat pipes, were used in predicting the minimum radiator mass for fixed thermal properties and fin efficiency. This mass is found to decrease monotonically with increasing fin conductivity. Sensitivities of the minimum mass designs to the problem parameters are determined

A numerical simulation of galaxy subcluster mergers

We present preliminary results of a 3-D numerical simulation of two merging subclusters of galaxies. By self-consistently modelling the intracluster gas and dark matter dynamics, we hope to gain insight as to how the dynamics of both relate to such observables as the cluster x-ray emission, radio source morphology, and velocity dispersions

Proximity-induced density-of-states oscillations in a superconductor/strong-ferromagnet system

We have measured the evolution of the tunneling density of states (DOS) in superconductor/ferromagnet (S/F) bilayers with increasing F-layer thickness, where F in our experiment is the strong ferromagnet Ni. As a function of increasing Ni thickness, we detect multiple oscillations in the DOS at the Fermi energy from differential conductance measurements. The features in the DOS associated with the proximity effect change from normal to inverted twice as the Ni thickness increases from 1 to 5 nm.Comment: 4 pages, 4 figure

Computer-Aided Student Study Group Formation

Students thrive in a variety of collaborative learning environments. Furthermore, research has shown student study groups are especially effective methods to promote learning. Our research project developed an artificially intelligent, Internet-based system that aids in formation of study groups outside the classroom setting. The system utilized a HTML/PHP/ CSS web interface with a MySQL database backend for the system design. Analysis of student feedback following system demonstration revealed significant support on viability and potential usage. A formal study will be conducted during the fall 2009 semester at Grand Valley State University and analysis of results will follow

Multiple Fluxes Influencing Amazonian River Chemistry

The rivers flowing through the Amazon Basin are both physically and chemically heterogeneous. Through detailed geochemical analyses, this study indicates that variability is primarily controlled by substrate lithology in the source region and the erosional regime. Observations suggest that it is possible to classify the chemical composition of Amazonian rivers according to the geochemistry of the soils in their catchment regions and vice versa.;The ability of microorganisms to undergo chemical exchanges with their aqueous environment, involving both the uptake and excretion of various elements, has been overlooked as an important factor in determining the chemistry of Amazonian rivers. Silicon extracted and precipitated by diatoms indicate that the dissolved silicon levels of the Rio Negro are in part controlled by biological activity. In the Rio Solimoes, both filamentous algae and bacteria were shown to bind and accumulate significant amounts of dissolved metals. In a solute-rich river system, the metal-loaded microorganisms play an important role in the transfer of metals from the hydrosphere to the sediment. It is not difficult to imagine that algae and bacteria could effectively cleanse the water of dissolved metals and partition them into the sediments.;In the Amazon Basin, many of the rivers are characterized by their high organic content and their solute-deficiency. In the Rio Negro, major cations such as Fe, Al, and Si are significantly bound into organo-metallic complexes, contributing largely to the mobilization and transport of these metals in the river. The high organic-inorganic matter ratio of this river also seems to provide sufficient reactive sites for the adsorption of trace metals. This process may cause significant changes in the overall chemical composition of rivers.;Lastly, anthropogenic forces now influence the nutrient dynamics of the forest system. Results indicate that numerous metals are released as aerosols through the combustion of vegetation. In addition, an entire suite of metals are concentrated in the residual ash, which potentially can be dispersed into the atmosphere. Analyses of radiogenic isotopes (Sr, Pb) in rainfall suggest that these emissions may provide nuclei for the condensation of water vapor, with the net result being a high concentration of dissolved metals in the precipitation. (Abstract shortened by UMI.

Numerical models of jet disruption in cluster cooling flows

We present a coherent picture for the formation of the observed diverse radio morphological structures in dominant cluster galaxies based on the jet Mach number. Realistic, supersonic, steady-state cooling flow atmospheres are evolved numerically and then used as the ambient medium through which jets of various properties are propagated. Low Mach number jets effectively stagnate due to the ram pressure of the cooling flow atmosphere while medium Mach number jets become unstable and disrupt in the cooling flow to form amorphous structures. High Mach number jets manage to avoid disruption and are able to propagate through the cooling flow

Effects of inulin, carrot and cellulose fibres on the properties of raw and fried chicken meatballs

The effects of inulin, carrot, and cellulose fibres (3%, 6%, and 9%) on raw and fried chicken meatballs were studied. Meatball pH, thiobarbituric acid reactive substances (TBARS), and colour values were determined for raw samples in refrigerated storage on the 1st, 5th and 10th days. The effects of fibres and their various levels on frying characteristics such as yield, diameter reduction, moisture retention, fat absorption, colour and sensory properties of fried chicken meatballs were evaluated. Fibres caused significant differences in the pH and TBARS values of the raw meatballs owing to their sources and levels. They improved colour properties (L: lightness, a: redness, b: yellowness) of the raw and fried samples. In addition, cellulose and carrot fibres affected the yield, moisture absorption, and diameter reduction values of the fried samples positively. In conclusion, the use of fibres in such products can affect product quality positively. The use of 3% inulin, 9% carrot, and 6% and 9% cellulose fibres had more beneficial effects on chicken meatballs.Keywords: Dietary fibre, frying, poultry products, product quality, storage stabilit

Analysis of radiative and phase-change phenomena with application to space-based thermal energy storage

The simplified geometry for the analysis is an infinite, axis symmetric annulus with a specified solar flux at the outer radius. The inner radius is either adiabatic (modeling Flight Experiment conditions), or convective (modeling Solar Dynamic conditions). Liquid LiF either contacts the outer wall (modeling ground based testing), or faces a void gap at the outer wall (modeling possible space based conditions). The analysis is presented in three parts: Part 3 considers and adiabatic inner wall and linearized radiation equations; part 2 adds effects of convection at the inner wall; and part 1 includes the effect of the void gap, as well as previous effects, and develops the radiation model further. The main results are the differences in melting behavior which can occur between ground based 1 g experiments and the microgravity flight experiments. Under 1 gravity, melted PCM will always contact the outer wall having the heat flux source, thus providing conductance from this source to the phase change front. In space based tests where a void gap may likely form during solidification, the situation is reversed; radiation is now the only mode of heat transfer and the majority of melting takes place from the inner wall