Optical enhancement of photomultiplier sensitivity

Transmission and reflection light losses are reduced by introducing light into end-window of device at an angle large enough to normal so total internal reflection occurs at both photocathode-vacuum and window-air interfaces

Lunar sample analysis

The surface composition of two samples from the highly shocked, glass-coated lunar basalt (12054) and from four glass-coated fragments from the 1-2 mm (14161) fines were examined by X-ray photoemission spectroscopy to determine whether the agglutination process itself is responsible for the difference between their surface and bulk compositions. Auger electron spectroscopy of glass balls from the 15425 and 74001 fines were analyzed to understand the nature, extent, and behavior of volatile phases associated with lunar volcanism. Initial results indicate that (1) volatiles, in the outer few atomic layers sampled, vary considerably from ball to ball; (2) variability over the surface of individual balls is smaller; (3) the dominant volatiles on the balls are S and Zn; and (4) other volatiles commonly observed are P, Cl, and K

Flight data analysis of power subsystem degradation at near synchronous altitude Quarterly report

Flight data analysis of spacecraft power subsystem degradation at near synchronous altitud

X-ray photoelectron spectroscopy investigation of the mixed anion GaSb/InAs heterointerface

X-ray photoelectron spectroscopy has been used to measure levels of anion cross-incorporation and to study interface formation for the mixed anion GaSb/lnAs heterojunction. Anion cross-incorporation was measured in 20 Å thick GaSb layers grown on lnAs, and 20 Å thick InAs layers grown on GaSb for cracked and uncracked sources. It was found that significantly less anion cross-incorporation occurs in structures grown with cracked sources. Interface formation was investigated by studying Sb soaks of InAs surfaces and As soaks of GaSb surfaces as a function of cracker power and soak time. Exchange of the group V surface atoms was found to be an increasing function of both cracker power and soak time. We find that further optimization of current growth parameters may be possible by modifying the soak time used at interfaces

A range expanding signal conditioner

Telemetry system modifications to improve signal resolution are described. Process uses zero suppression technique which consists of subtracting known voltage from input and amplifying remainder. Schematic diagram of circuit is provided and details of operation are presented

Study of interface asymmetry in InAs–GaSb heterojunctions

We present reflection high energy electron diffraction, secondary ion mass spectroscopy, scanning tunneling microscopy and x‐ray photoelectron spectroscopy studies of the abruptness of InAs–GaSb interfaces. We find that the interface abruptness depends on growth order: InAs grown on GaSb is extended, while GaSb grown on InAs is more abrupt. We first present observations of the interfacial asymmetry, including measurements of band alignments as a function of growth order. We then examine more detailed studies of the InAs–GaSb interface to determine the mechanisms causing the extended interface. Our results show that Sb incorporation into the InAs overlayer and As exchange for Sb in the GaSb underlayer are the most likely causes of the interfacial asymmetry

Optical enhancement of sensitivity in laser Doppler velocity systems

Utilization of optical enhancement techniques prevents loss of light by reflections at the photocathode of a photomultiplier and increases signal detection sensitivity

Laser velocimeter for simultaneous two-dimensional velocity measurements

Laser velocimeter provides simultaneous orthogonal measurements in manner which minimizes many problems attending prior systems, and allows spatial traversing of flowfield in order to obtain velocity profiles. Velocimeter permits rapid interrogation of unsteady flows where area of interest is of the order of one meter in extent and flow does not vary appreciably over time of about one second

Studies of satellite support to weather modification in the western US region

The applications of meteorological satellite data to both summer and winter weather modification programs are addressed. Appraisals of the capability of satellites to assess seedability, to provide real-time operational support, and to assist in the post-experiment analysis of a seeding experiment led to the incorporation of satellite observing systems as a major component in the Bureau of Reclamations weather modification activities. Satellite observations are an integral part of the South Park Area cumulus experiment (SPACE) which aims to formulate a quantitative hypothesis for enhancing precipitation from orographically induced summertime mesoscale convective systems (orogenic mesoscale systems). Progress is reported in using satellite observations to assist in classifying the important mesoscale systems, and in defining their frequency and coverage, and potential area of effect. Satellite studies of severe storms are also covered

The ecological niche of storm-petrels in the North Pacific and a global model of dimethylsulfide concentration

Thesis (M.S.) University of Alaska Fairbanks, 2010Ecological niche modeling techniques were used to create global, monthly predictions of sea surface dimethylsulfide (DMS) concentrations, and breeding season distribution of Leach's Storm-Petrel (Oceanodroma luncorhoa) and Fork-Tailed Storm-Petrel (O. furcata) in the North Pacific. This work represents the first attempt to model DMS concentrations on a global scale using ecological niche modeling, and the first models of Storm-Petrel distribution for the North Pacific. Storm-Petrels have been shown to be attracted to DMS, and it is therefore likely that a model of sea surface DMS concentration would help explain and predict Storm-Petrel distribution. We have successfully created the most accurate models of sea surface DMS concentrations that we are currently aware of with global correlation (r) values greater than 0.45. We also created Storm-Petrel models with area under the receiver operating characteristic curve (AUC) values of greater than 0.90. Using just DMS as a predictor variable we were also able to create models with AUC values upwards of 0.84. Future conservation efforts on pelagic seabird species may be dependent on models like the ones created here, and it is therefore important that these methods are improved upon to help seabird management on all scales (global, national, regional and local).General introduction -- Storm-petrels of the North Pacific -- Dimethylsulfide -- Ecological niche modeling -- Data mining (TreeNet) -- Study goals -- References -- 1. Predicting monthly surface seawater dimethylsulfide (DMS) concentrations on a global scale using a machine learning algorithm (TreeNet) -- 2. Predicted distribution of storm-petrels (Oceanodroma) in the North Pacific using Geographic Information Systems (GIS), TreeNet and dimethylsulfide (DMS) concentrations -- Acknowledgements -- Literature cited -- General conclusions -- Dimethylsulfide -- Storm petrels -- Final conclusions -- References -- Appendices