Use of inedible wheat residues from the KSC-CELSS breadboard facility for production of fungal cellulase

Cellulose and xylan (a hemicellulose) comprise 50 percent of inedible wheat residue (which is 60 percent of total wheat biomass) produced in the Kennedy Space Center Closed Ecological Life Support System (CELSS) Breadboard Biomass Production Chamber (BPC). These polysaccharides can be converted by enzymatic hydrolysis into useful monosaccharides, thus maximizing the use of BPC volume and energy, and minimizing waste material to be treated. The evaluation of CELSS-derived wheat residues for production for cellulase enzyme complex by Trichoderma reesei and supplemental beta-glucosidase by Aspergillus phoenicis is in progress. Results to date are given

Optimal aero-structural design of an adaptive surface for boundary layer motivation using an auxetic lattice skin

The aero-structural design of an adaptive vortex generator for repeatable, elastic, deployment and retraction from an aerodynamically clean surface is presented. A multidisciplinary objective function, containing geometrically nonlinear nite element analysis and large eddy simulation, is used to derive the optimal adaptive geometry for increasing the momentum of the near wall uid. It is found that the rapid increase of in-plane membrane stress with de ection is a signi cant limitation on achievable deformation of a continuous skin with uniform section. Use of a 2D auxetic lattice structure in place of the continuous skin allows signi cantly larger deformations and thus a signi cant improvement in performance. The optimal deformed geometry is replicated statically and the e ect on the boundary layer is validated in a wind tunnel experiment. The lattice structure is then manufactured and actuated. The deformed geometry is shown to compare well with the FEA predictions. The surface is re-examined post actuation and shown to return to the initial position, demonstrating the deformation is elastic and hence repeatable

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

Nearby Clumpy, Gas Rich, Star Forming Galaxies: Local Analogs of High Redshift Clumpy Galaxies

Luminous compact blue galaxies (LCBGs) have enhanced star formation rates and compact morphologies. We combine Sloan Digital Sky Survey data with HI data of 29 LCBGs at redshift z~0 to understand their nature. We find that local LCBGs have high atomic gas fractions (~50%) and star formation rates per stellar mass consistent with some high redshift star forming galaxies. Many local LCBGs also have clumpy morphologies, with clumps distributed across their disks. Although rare, these galaxies appear to be similar to the clumpy star forming galaxies commonly observed at z~1-3. Local LCBGs separate into three groups: 1. Interacting galaxies (~20%); 2. Clumpy spirals (~40%); 3. Non-clumpy, non-spirals with regular shapes and smaller effective radii and stellar masses (~40%). It seems that the method of building up a high gas fraction, which then triggers star formation, is not the same for all local LCBGs. This may lead to a dichotomy in galaxy characteristics. We consider possible gas delivery scenarios and suggest that clumpy spirals, preferentially located in clusters and with companions, are smoothly accreting gas from tidally disrupted companions and/or intracluster gas enriched by stripped satellites. Conversely, as non-clumpy galaxies are preferentially located in the field and tend to be isolated, we suggest clumpy, cold streams, which destroy galaxy disks and prevent clump formation, as a likely gas delivery mechanism for these systems. Other possibilities include smooth cold streams, a series of minor mergers, or major interactions.Comment: 22 pages, 5 figure

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

Optical nonlinearity enhancement of graded metallic films

The effective linear and third-order nonlinear susceptibility of graded metallic films with weak nonlinearity have been investigated. Due to the simple geometry, we were able to derive exactly the local field inside the graded structures having a Drude dielectric gradation profile. We calculated the effective linear dielectric constant and third-order nonlinear susceptibility. We investigated the surface plasmon resonant effect on the optical absorption, optical nonlinearity enhancement, and figure of merit of graded metallic films. It is found that the presence of gradation in metallic films yields a broad resonant plasmon band in the optical region, resulting in a large enhancement of the optical nonlinearity and hence a large figure of merit. We suggest experiments be done to check our theoretical predictions, because graded metallic films can be fabricated more easily than graded particles.Comment: 11 pages, 2 eps figures, submitted to Applied Physics Letter

Matching small β\beta functions using centroid jitter and two beam position monitors

Matching to small beta functions is required to preserve emittance in plasma accelerators. The plasma wake provides strong focusing fields, which typically require beta functions on the mm-scale, comparable to those found in the final focusing of a linear collider. Such beams can be time consuming to experimentally produce and diagnose. We present a simple, fast, and noninvasive method to measure Twiss parameters in a linac using two beam position monitors only, relying on the similarity of the beam phase space and the jitter phase space. By benchmarking against conventional quadrupole scans, the viability of this technique was experimentally demonstrated at the FLASHForward plasma-accelerator facility.Comment: 8 pages, 7 figure