Utilization of the water soluable fraction of wheat straw as a plant nutrient source

Recovery of water soluble, inorganic nutrients from the inedible portion of wheat was found to be an effective means of recycling nutrients within hydroponic systems. Through aqueous extraction (leaching), 60 percent of the total inorganic nutrient weight was removed from wheat straw and roots, although the recovery of individual nutrients varied. Leaching also removed about 20 percent of the total organic carbon from the biomass. In terms of dry weight, the leachate was comprised of approximately 60 percent organic and 40 percent inorganic compounds. Direct use of wheat straw leachate in static hydroponic systems had an inhibitory effect on wheat growth, both in the presence and absence of microorganisms. Biological treatment of leachate either with a mixed microbial community or the oyster mushroom Pleurotus ostreatus L., prior to use in hydroponic solutions, significantly reduced both the organic content and the inhibitory effects of the leachate. The inhibitory effects of unprocessed leachate appear to be a result of rapidly acting phytotoxic compounds that are detoxified by microbial activity. Leaching holds considerable promise as a method for nutrient recycling in a Controlled Ecological Life Support System (CELSS)

Evaluation of shuttle solid rocket booster case materials. Corrosion and stress corrosion susceptibility of several high temperature materials

Candidate alloys for the Shuttle Solid Rocket Booster (SRB) case were tested under simulated service conditions to define subcritical flaw growth behavior under both sustained and cyclic loading conditions. The materials evaluated were D6AC and 18 Ni maraging steel, both heat treated to a nominal yield strength of 1380 MN/sq m (200 ksi). The sustained load tests were conducted by exposing precracked, stressed specimens of both alloys to alternate immersion in synthetic sea water. It was found that the corrosion and stress corrosion resistance of the 18 Ni maraging steel were superior to that of the D6AC steel under these test conditions. It was also found that austenitizing temperature had little influence on the threshold stress intensity of the D6AC. The cyclic tests were conducted by subjecting precracked surface-flawed specimens of both alloys to repeated load/thermal/environmental profiles which were selected to simulate the SRB missions. It was found that linear removal operations that involve heating to 589 K (600 F) cause a decrease in cyclic life of D6AC steel relative to those tests conducted with no thermal cycling

Supercritical Conversion Of The 3rd Blue Phase To The Isotropic-Phase In A Highly Chiral Liquid-Crystal

The results of two independent experiments in the vicinity of the “transition” from the third blue phase ( BPIII) to isotropic phase ( I) are reported for a highly chiral liquid crystal. Heat capacity measurements using a high-resolution calorimeter and dynamic light-scattering measurements using circularly polarized light have been performed. The data show a continuous evolution of BPIII into I with no critical fluctuations. This is strong evidence that the BPIII-I transition in this compound is supercritical, indicating that the BPIII and I phases possess the same macroscopic symmetry

Epitaxial silicon grown on CeO2/Si(111) structure by molecular beam epitaxy

Using electron beam evaporation, a Si/CeO2/Si(111) structure has been grown in a molecular beam epitaxy machine. In situ low energy electron diffraction, cross sectional transmission electron microscopy, selected area diffraction, and atomic force microscopy have been used to structurally characterize the overlying silicon layer and show it to be single crystalline and epitaxially oriented. Rutherford backscattering and energy dispersive x-ray analysis have been used to confirm the presence of a continuous 23 Å CeO2 layer at the interface. Rutherford backscattering and x-ray photoemission spectroscopy show an additional presence of cerium both at the exposed silicon surface and incorporated in low levels (~ 1%) within the silicon film, suggesting a growth mechanism with cerium riding atop the silicon growth front leaving behind small amounts of cerium incorporated in the growing silicon crystal

The Evolution of Luminous Compact Blue Galaxies: Disks or Spheroids?

Luminous compact blue galaxies (LCBGs) are a diverse class of galaxies characterized by high luminosities, blue colors, and high surface brightnesses. Residing at the high luminosity, high mass end of the blue sequence, LCBGs sit at the critical juncture of galaxies that are evolving from the blue to the red sequence. Yet we do not understand what drives the evolution of LCBGs, nor how they will evolve. Based on single-dish HI observations, we know that they have a diverse range of properties. LCBGs are HI-rich with M(HI)=10^{9-10.5} M(sun), have moderate M(dyn)=10^{10-12} M(sun), and 80% have gas depletion timescales less than 3 Gyr. These properties are consistent with LCBGs evolving into low-mass spirals or high mass dwarf ellipticals or dwarf irregulars. However, LCBGs do not follow the Tully-Fisher relation, nor can most evolve onto it, implying that many LCBGs are not smoothly rotating, virialized systems. GMRT and VLA HI maps confirm this conclusion revealing signatures of recent interactions and dynamically hot components in some local LCBGs, consistent with the formation of a thick disk or spheroid. Such signatures and the high incidence of close companions around LCBGs suggest that star formation in local LCBGs is likely triggered by interactions. The dynamical masses and apparent spheroid formation in LCBGs combined with previous results from optical spectroscopy are consistent with virial heating being the primary mechanism for quenching star formation in these galaxies.Comment: 4 pages, 1 figure, to appear in "Hunting for the Dark: The Hidden Side of Galaxy Formation", Malta, 19-23 Oct. 2009, eds. V.P. Debattista & C.C. Popescu, AIP Conf. Se

Physical Chemistry

Contains a report on a research project

Low Temperature Physics

Contains reports on one research project

Indium oxide diffusion barriers for Al/Si metallizations

Indium oxide (In2O3) films were prepared by reactive rf sputtering of an In target in O2/Ar plasma. We have investigated the application of these films as diffusion barriers in Si/In2O3/Al and Si/TiSi2.3/In2O3/Al metallizations. Scanning transmission electron microscopy together with energy dispersive analysis of x ray of cross-sectional Si/In2O3/Al specimens, and electrical measurements on shallow n + -p junction diodes were used to evaluate the diffusion barrier capability of In2O3 films. We find that 100-nm-thick In2O3 layers prevent the intermixing between Al and Si in Si/In2O3/Al contacts up to 650°C for 30 min, which makes this material one of the best thin-film diffusion barriers on record between Al and Si. (The Si-Al eutectic temperature is 577°C, Al melts at 660°C.) When a contacting layer of titanium silicide is incorporated to form a Si/TiSi2.3/In2O3/Al metallization structure, the thermal stability of the contact drops to 600°C for 30 min heat treatment