Small, efficient power supply for xenon lamps

Device, which operates from 28 V dc, has four sections, a preregulator, a dc-to-dc converter, a current regulator, and a high voltage starter. The unique characteristics of the individual sections are described

Temperature dependence of species concentrations near the substrate during diamond chemical vapor deposition

Measurements have been made of the temperature dependence of CH3, CH4, and C2H2 very near the substrate during filament-assisted diamond growth. CH3 was detected using (2+1) resonance-enhanced multiphoton ionization (REMPI), and CH4 and C2H2 concentrations were measured using sampling mass spectrometry. A strong dependence of the CH3 REMPI signal on substrate temperature was observed, which at low temperatures may be characterized as having an activation energy of approximately 4±1 kcal/mole. Methane and acetylene, on the other hand, are relatively independent of substrate temperature. These results are most likely due to recombination of methyl to methane or ethane in the cool gas layer near the substrate or on the surface at low substrate temperatures

Opto-mechanical subsystem with temperature compensation through isothemal design

An opto-mechanical subsystem for supporting a laser structure which minimizes changes in the alignment of the laser optics in response to temperature variations is described. Both optical and mechanical structural components of the system are formed of the same material, preferably beryllium, which is selected for high mechanical strength and good thermal conducting qualities. All mechanical and optical components are mounted and assembled to provide thorough thermal coupling throughout the subsystem to prevent the development of temperature gradients

Detection of Turbidity Dynamics in Tampa Bay, Florida Using Multispectral Imagery from ERTS-1

Detection of turbidity dynamics in Tampa Bay, Florida using multispectral imagery from ERTS-

Spatial Analysis of Market Linkages in North Carolina Using Threshold Autoregression Models with Variable Transaction Costs

In North Carolina, where soybeans and corn are the two primary crops, the recent increase in the demand for U.S. corn has triggered a shift of farm acreage from soybeans to corn, leading to a rapid rise in prices of both commodities. However, the rate of the price changes, as well as the price level, is significantly different in markets that are located in different parts of the state. This study extends the literature that examines linkages between spatially separated markets by using a threshold autoregressive model with a less restrictive assumption for estimating the transaction cost neutral band -- the band within which trade is not profitable. This generalization allows the neutral band of transactions costs to change according to various external factors, including fuel costs and seasonality. The estimation results indicate that for longer time series data, variable thresholds models statistically outperform the constant thresholds specification, and may provide a better representation of corn and soybean price data. Additionally, impulse response functions that use the asymmetric variable threshold model parameters indicate that the magnitude of the shock as well as the time-to-price-parity-equilibrium in the linked markets may be underestimated if a constant thresholds specification is implemented.threshold autoregression, spatially separated markets, impulse response, neutral band, Demand and Price Analysis, Marketing, Q11, Q13,

Simulating star formation in molecular cloud cores IV. The role of turbulence and thermodynamics

We perform SPH simulations of the collapse and fragmentation of low-mass cores having different initial levels of turbulence (alpha_turb=0.05,0.10,0.25). We use a new treatment of the energy equation which captures the transport of cooling radiation against opacity due to both dust and gas (including the effects of dust sublimation, molecules, and H^- ions). We also perform comparison simulations using a standard barotropic equation of state. We find that -- when compared with the barotropic equation of state -- our more realistic treatment of the energy equation results in more protostellar objects being formed, and a higher proportion of brown dwarfs; the multiplicity frequency is essentially unchanged, but the multiple systems tend to have shorter periods (by a factor ~3), higher eccentricities, and higher mass ratios. The reason for this is that small fragments are able to cool more effectively with the new treatment, as compared with the barotropic equation of state. We find that the process of fragmentation is often bimodal. The first protostar to form is usually, at the end, the most massive, i.e. the primary. However, frequently a disc-like structure subsequently forms round this primary, and then, once it has accumulated sufficient mass, quickly fragments to produce several secondaries. We believe that this delayed fragmentation of a disc-like structure is likely to be an important source of very low-mass hydrogen-burning stars and brown dwarfs.Comment: 14 pages, 8 figures. Accepted for publication by A&

Experiment definition phase shuttle laboratory (LDRL-10.6 experiment): Shuttle sortie to elliptical orbit satellite

The following topics were reviewed: (1) design options for shuttle terminal, (2) elliptical orbit satellite design options, (3) shuttle terminal details, (4) technology status and development requirements, (5) transmitter technology, and (6) carbon dioxide laser life studies

Addressable time division multiplexer system /cable and connector study/ Final report

Reliability studies of single interrogation and single data cables used in prototype addressable time division multiplexer syste