High efficiency thermionic converter studies

The objective is to improve thermionic converter performance by means of reduced interelectrode losses, greater emitter capabilities, and lower collector work functions until the converter performance level is suitable for out-of-core space reactors and radioisotope generators. Electrode screening experiments have identified several promising collector materials. Back emission work function measurements of a ZnO collector in a thermionic diode have given values less than 1.3 eV. Diode tests were conducted over the range of temperatures of interest for space power applications. Enhanced mode converter experiments have included triodes operated in both the surface ionization and plasmatron modes. Pulsed triodes were studied as a function of pulse length, pulse potential, inert gas fill pressure, cesium pressure, spacing, emitter temperature and collector temperature. Current amplifications (i.e., mean output current/mean grid current) of several hundred were observed up to output current densities of one amp/sq cm. These data correspond to an equivalent arc drop less than 0.1 eV

High efficiency thermionic converter studies

Research in thermionic energy conversion technology is reported. The objectives were to produce converters suitable for use in out of core space reactors, radioisotope generators, and solar satellites. The development of emitter electrodes that operate at low cesium pressure, stable low work function collector electrodes, and more efficient means of space charge neutralization were investigated to improve thermionic converter performance. Potential improvements in collector properties were noted with evaporated thin film barium oxide coatings. Experiments with cesium carbonate suggest this substance may provide optimum combinations of cesium and oxygen for thermionic conversion

Overview of the Langley subsonic research effort on SCR configuration

Recent advances achieved in the subsonic aerodynamics of low aspect ratio, highly swept wing designs are summarized. The most significant of these advances was the development of leading edge deflection concepts which effectively reduce leading edge flow separation. The improved flow attachment results in substantial improvements in low speed performance, significant delay of longitudinal pitch up, increased trailing edge flap effectiveness, and increased lateral control capability. Various additional theoretical and/or experimental studies are considered which, in conjunction with the leading edge deflection studies, form the basis for future subsonic research effort

Isolation and characterization of the herpes simplex virus 1 terminase complex

During herpes simplex virus 1 (HSV-1) infection, empty procapsids are assembled and subsequently filled with the viral genome by means of a protein complex called the terminase, which is comprised of the HSV-1 UL15, UL28, and UL33 proteins. Biochemical studies of the terminase proteins have been hampered by the inability to purify the intact terminase complex. In this study, terminase complexes were isolated by tandem-affinity purification (TAP) using recombinant viruses expressing either a full-length NTAP-UL28 fusion protein (vFH476) or a C-terminally truncated NTAP-UL28 fusion protein (vFH499). TAP of the UL28 protein from vFH476-infected cells, followed by silver staining, Western blotting, and mass spectrometry, identified the UL15, UL28, and UL33 subunits, while TAP of vFH499-infected cells confirmed previous findings that the C terminus of UL28 is required for UL28 interaction with UL33 and UL15. Analysis of the oligomeric state of the purified complexes by sucrose density gradient ultracentrifugation revealed that the three proteins formed a complex with a molecular mass that is consistent with the formation of a UL15-UL28-UL33 heterotrimer. In order to assess the importance of conserved regions of the UL15 and UL28 proteins, recombinant NTAP-UL28 viruses with mutations of the putative UL28 metal-binding domain or within the UL15 nuclease domain were generated. TAP of UL28 complexes from cells infected with each domain mutant demonstrated that the conserved cysteine residues of the putative UL28 metal-binding domain and conserved amino acids within the UL15 nuclease domain are required for the cleavage and packaging functions of the viral terminase, but not for terminase complex assembly

Adapting SAM for CDF

The CDF and D0 experiments probe the high-energy frontier and as they do so have accumulated hundreds of Terabytes of data on the way to petabytes of data over the next two years. The experiments have made a commitment to use the developing Grid based on the SAM system to handle these data. The D0 SAM has been extended for use in CDF as common patterns of design emerged to meet the similar requirements of these experiments. The process by which the merger was achieved is explained with particular emphasis on lessons learned concerning the database design patterns plus realization of the use cases.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics (CHEP03), La Jolla, Ca, USA, March 2003, 4 pages, pdf format, TUAT00

From Skew-Cyclic Codes to Asymmetric Quantum Codes

We introduce an additive but not $\mathbb{F}_4$-linear map $S$ from $\mathbb{F}_4^{n}$ to $\mathbb{F}_4^{2n}$ and exhibit some of its interesting structural properties. If $C$ is a linear $[n,k,d]_4$-code, then $S(C)$ is an additive $(2n,2^{2k},2d)_4$-code. If $C$ is an additive cyclic code then $S(C)$ is an additive quasi-cyclic code of index $2$. Moreover, if $C$ is a module $\theta$-cyclic code, a recently introduced type of code which will be explained below, then $S(C)$ is equivalent to an additive cyclic code if $n$ is odd and to an additive quasi-cyclic code of index $2$ if $n$ is even. Given any $(n,M,d)_4$-code $C$, the code $S(C)$ is self-orthogonal under the trace Hermitian inner product. Since the mapping $S$ preserves nestedness, it can be used as a tool in constructing additive asymmetric quantum codes.Comment: 16 pages, 3 tables, submitted to Advances in Mathematics of Communication