Study and development of a mathematical analysis for the performance assessment of space communication system parameters

Electronic computer program user manual for optimum design of space communication syste

User's manual for COPTRAN, a method of optimum communication system design

User manual for COPTRAN /communication system optimization program translator

COPTRAN - A method of optimum communication systems design

Single set of mathematical expressions describes system cost and probability of error of data transmission in terms of four basic parameters in the link equation. A Lagrange multiplier sets up equations whose solutions yield the optimum values for system design considerations and weight and cost values

Parametric analysis of microwave and laser systems for communication and tracking. Volume 2 - System selection

System selection criteria of microwave and laser systems for communication and tracking - Vol.

Childhood Vaccination and Autism

In March, 2008, parents of a girl in Georgia were ruled to be entitled to compensation because their daughter developed autistic symptoms after being vaccinated with childhood vaccines (Doheny, 2008). This ruling truly questions the necessity of vaccination for childhood diseases and puts the question in the mind of every parent as to if they should vaccinate their child or not. The purpose of this study is to review literature on the epidemiologic relationship between childhood vaccinations and the development of autism

Central mode and soft mode behavior in PbMg1/Nb2/3O3 relaxor ferroelectric

The relaxor ferroelectric PbMg1/Nb2/3O3 was investigated by means of broad-band dielectric and Fourier Transform Infrared (FTIR) transmission spectroscopy in the frequency range from 1 MHz to 15 THz at temperatures between 20 and 900 K using PMN films on infrared transparent sapphire substrates. While thin film relaxors display reduced dielectric permittivity at low frequencies, their high frequency intrinsic or lattice response is shown to be the same as single crystal/ceramic specemins. It was observed that in contrast to the results of inelastic neutron scattering, the optic soft mode was underdamped at all temperatures. On heating, the TO1 soft phonon followed the Cochran law with an extrapolated critical temperature equal to the Burns temperature of 670 K and softened down to 50 cm-1. Above 450 K the soft mode frequency leveled off and slightly increased above the Burns temperature. A central mode, describing the dynamics of polar nanoclusters appeared below the Burns temperature at frequencies near the optic soft mode and dramatically slowed down below 1 MHz on cooling below room temperature. It broadened on cooling, giving rise to frequency independent losses in microwave and lower frequency range below the freezing temperature of 200 K. In addition, a new heavily damped mode appeared in the FTIR spectra below the soft mode frequency at room temperature and below. The origin of this mode as well as the discrepancy between the soft mode damping in neutron and infrared spectra is discussed.Comment: 7 pages with 7 figures, submitted to Phys. Rev.

Hubbard physics in the symmetric half-filled periodic Anderson-Hubbard model

Two very different methods -- exact diagonalization on finite chains and a variational method -- are used to study the possibility of a metal-insulator transition in the symmetric half-filled periodic Anderson-Hubbard model. With this aim we calculate the density of doubly occupied $d$ sites as a function of various parameters. In the absence of on-site Coulomb interaction ($U_f$) between $f$ electrons, the two methods yield similar results. The double occupancy of $d$ levels remains always finite just as in the one-dimensional Hubbard model. Exact diagonalization on finite chains gives the same result for finite $U_f$, while the Gutzwiller method leads to a Brinkman-Rice transition at a critical value ($U_d^c$), which depends on $U_f$ and $V$.Comment: 10 pages, 5 figure

PRELIMINARY STUDY OF CERAMICS FOR IMMOBILIZATION OF ADVANCED FUEL CYCLE REPROCESSING WASTES

The Savannah River National Laboratory (SRNL) developed a series of ceramic waste forms for the immobilization of Cesium/Lanthanide (CS/LN) and Cesium/Lanthanide/Transition Metal (CS/LN/TM) waste streams anticipated to result from nuclear fuel reprocessing. Simple raw materials, including Al{sub 2}O{sub 3}, CaO, and TiO{sub 2} were combined with simulated waste components to produce multiphase ceramics containing hollandite-type phases, perovskites (particularly BaTiO{sub 3}), pyrochlores, zirconolite, and other minor metal titanate phases. Identification of excess Al{sub 2}O{sub 3} via X-ray Diffraction (XRD) and Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM/EDS) in the first series of compositions led to a Phase II study, with significantly reduced Al{sub 2}O{sub 3} concentrations and increased waste loadings. Three fabrication methodologies were used, including melting and crystallizing, pressing and sintering, and Spark Plasma Sintering (SPS), with the intent of studying phase evolution under various sintering conditions. XRD and SEM/EDS results showed that the partitioning of the waste elements in the sintered materials was very similar, despite varying stoichiometry of the phases formed. The Phase II compositions generally contained a reduced amount of unreacted Al{sub 2}O{sub 3} as identified by XRD, and had phase assemblages that were closer to the initial targets. Chemical composition measurements showed no significant issues with meeting the target compositions. However, volatilization of Cs and Mo was identified, particularly during melting, since sintering of the pressed pellets and SPS were performed at lower temperatures. Partitioning of some of the waste components was difficult to determine via XRD. SEM/EDS mapping showed that those elements, which were generally present in small concentrations, were well distributed throughout the waste forms. Initial studies of radiation damage tolerance using ion beam irradiation at Los Alamos National Laboratory (LANL) showed little if any modification of the material after irradiation. Additional study in this area is needed. Chemical durability was briefly studied using the Product Consistency Test (PCT). Most of the elements measured were retained by the ceramic waste forms, indicating good chemical durability. Cs, Mo, and Rb were released at somewhat higher rates as compared to the matrix components, although benchmark compositions and additional characterization are needed in order to qualify the PCT results

Factors Influencing the Size of Student Debt

The overall purpose of this study is to analyze the influence of selected sociodemographic variables and students\u27 knowledge about their educational loans on the amount of total debt. The specific objectives were to: (1) ascertain students\u27 perception of knowledge about their student loans, as well as their actual knowledge about various aspects of their student loans including: when they first borrowed, interest rate, grace period, when payment will begin, amount of monthly payment, and their overall self-reported level of knowledge; and (2) ascertain the relationship between students\u27 sociodemographic characteristics and level of knowledge on total debt