Digital Commons Network^™

Mammal Research In Southern Africa: Present Patterns And Future Priorities, Johan T. Du Toit, L. S. Broomhall

Wildland Resources Faculty Publications

We conducted a survey to identify present patterns and future priorities for mammal research in southern Africa (countries including and southwards of Angola, Zambia and Tanzania). Two sets of peer-reviewed journals were scanned for papers on southern African mammal research over the period 1988-1998: one set comprised five journals published in South Africa; the other comprised 10 journals published abroad. For the same period we reviewed titles of M.Sc. and Ph.D. dissertations completed in zoology departments of South African universities. A questionaire was administered by e-mail to. 126 researchers active in mammal research in southern Africa, concurrently with a separate …

Insights, Fall, 1999, Utah State University

Discovery Magazine

Bi-annual alumni newsletter for the College of Science of Utah State University in Logan.

Video And Photometric Observations Of A Sprite In Coincidence With A Meteor-Triggered Jet Event, D. M. Suszcynsky, R. Strabley, R. Roussel-Dupre, E. M.D. Symbalisty, R. A. Armstrong, W. A. Lyons, Michael J. Taylor

All Physics Faculty Publications

Video and photometric observations of a meteor-triggered “jet” event in association with the occurrence of a sprite were collected during the SPRITES '98 campaign. The event raises interest in the question of possible meteoric triggering of upper atmospheric transients as originally suggested by Muller [1995]. The event consisted of three stages: (1) the observation of a moderately bright meteor, (2) the development of a sprite in the immediate vicinity of the meteor as the meteor reached no lower than ∼70 km altitude, and (3) a slower-forming jet of luminosity that appeared during the late stages of the sprite and propagated …

Environmental Assessment, Decision Record, And Finding Of No Significant Impact For The Ixc Communications, Inc.'S Proposed Fiber Optic Telecommunications System, Denver, Colorado, To Salt Lake City, Utah, U.S. Department Of The Interior, Bureau Of Land Management

All U.S. Government Documents (Utah Regional Depository)

IXC proposes to install and operate a telecommunications system from Denver, Colorado, to Salt Lake City, Utah, to provide service to these and other western cities. The approximately 611-mile long cable would cross 116 miles of federal land administered by the BLM (all within Wyoming), 1 mile of National Forest lands administered by the Forest Service (all within Utah), and 494 miles of state, county, municipal, and private lands. Three 1.9-inch and three 2.4-inch high-density polyethylene conduits would be installed simultaneously and a fiber optic cable would be installed in one conduit; the other conduits would be used for future …

1991-1992 & 1996 Utah Usage Of Ems Services By Children: Year Iii Research Report, Intermountain Injury Control Research Center, U.S. Department Of Commerce

All U.S. Government Documents (Utah Regional Depository)

This study examined how Utah children used emergency medical services (EMS) and related hospital care in 1991-1992. The EMS and hospital records were linked using special software (probabilistic linkage) . The principal findings of the study concerned the care of young children less than 5 years of age. They received fewer procedures prior to being transported to a hospital and required more time at the scene for assessment. Some interventions such as splinting of fractured arms prior to transport to a hospital were related to reduced hospital charges. Ambulance and hospital charges for children were estimated to by $35,000,000 not …

Mormon Domestic Life In The 1870s: Pandemonium Or Arcadia?, Utah State University Press

Arrington Annual Lecture

No abstract provided.

Marginalia No. 7, Merrill-Cazier Library

Marginalia

Issue Number 7: the proverb issue Autumn 1999

A MESSAGE FROM DEAN WHITE - new Dean of Libraries introduces herself.

“BIG THINGS COME IN SMALL PACKAGES”-Randy Williams on Proverbs, Power and Books.

INSTRUCTION: ‘IT TAKES SHARP WITS…’-Listing of Reference Librarians & Library instruction services

MERRILL LIBRARY RENOVATIONS-A brief discussion of recent changes in the Merrill Library

THE ART OF LARRY ELSNER-Art curator Rose Milovich on the upcoming exhibit and silent auction fund-raiser

USU LIBRARIES EXHIBITION SCHEDULE, 1999-Upcoming exhibits in the Library Gallery

THE STANFORD O. CAZIER SCITECH LIBRARY-Director Max Peterson reports

UTAH ACADEMIC LIBRARY CONSORTIUM- Assoc. Director, Robert Murdoch describes …

Utah Science Vol. 59 No. 4, Fall 1999

Utah Science

2 UTAH AG GETTING A TASTE FOR ONIONS

8 FEEDING THE OVERFED NO WAY TO PROSPERITY

11 A NEW RIPPLE IN THE AMBER WAVES

18 HOUSING THE NEW CENTURY

23 AT HOME ON THE RANCHETTE

26 WHAT'S BEEN DONE FOR YOU LATELY

Water Resources Systems Analysis - Course Notes, A Bruce Bishop, Trevor Hughes, Mac Mckee

All ECSTATIC Materials

Water resources systems analysis course notes for CEE 6410 taught at Utah State University. Coverage includes:

Chapter 1 - Concepts and methods

Chapter 2 - Linear programming-introduction and graphical methods

Chapter 3 - Linear programming - simplex method

Chapter 4 - Linear programming - applications to simple water problems

Chapter 5 - Dual LP and post optimality analysis

Chapter 6 - Integer programming

Chapter 7 - More applications of integer programmign

Chapter 8 - Piecewise linearization

Chapter 9 - Other types of LP models

Chapter 10 - Dynamic programming

Chapter 11 - Gradient-based nonlinear optimization methods

Chapter 12 - Genetic …

Behavioral Checklist Forms, Unknown Unknown

All Current Publications

No abstract provided.

Abortion In Cattle, Clell Bagley

All Current Publications

Abortion is the premature expulsion of the fetus from the dam and usually occurs because the fetus has died in-utero. If death occurs at 1-2 months of gestation, it is usually termed “early embryonic death.”

Conformal Actions In Any Dimension, Andre Wehner, James Thomas Wheeler

All Physics Faculty Publications

Biconformal gauging of the conformal group gives a scale-invariant volume form, permitting a single form of the action to be invariant in any dimension. We display several 2n-dimensional scale-invariant polynomial actions and a dual action. We solve the field equations for the most general action linear in the curvatures for a minimal torsion geometry. In any dimension n > 2, the solution is foliated by equivalent n-dimensional Ricci-flat Riemannian space-times, and the full 2n-dimensional space is symplectic. Two fields defined entirely on the Riemannian submanifolds completely determine the solution: a metric e_μ^α, and …

Effects Of The Vertical Plasma Drift Velocity On The Generation And Evolution Of Equatorial Spread F, Bela G. Fejer, L. Scherliess, E. R. De Paula

Bela G. Fejer

We use radar observations from the Jicamarca Observatory from 1968 to 1992 to study the effects of the F region vertical plasma drift velocity on the generation and evolution of equatorial spread F. The dependence of these irregularities on season, solar cycle, and magnetic activity can be explained as resulting from the corresponding effects on the evening and nighttime vertical drifts. In the early night sector, the bottomside of the F layer is almost always unstable. The evolution of the unstable layer is controlled by the history of the vertical drift velocity. When the drift velocities are large enough, the …

Salt Lake City, Utah Profile Of Drug Indicators, Office Of National Drug Control Policy, Drug Policy Information Clearinghouse

All U.S. Government Documents (Utah Regional Depository)

The following profile contains information on demographics, political figures, funding, programs, crime, drug use, drug trafficking, and enforcement statistics.

Final Intrinsic Remediation, Engineering Evaluation/Cost Analysis Addendum For Ust Site 870, Hill Air Force Base, Ogden, Utah, Parsons Engineering Science, Inc.

All U.S. Government Documents (Utah Regional Depository)

This report was prepared for the Air Force Center for Environmental Excellence (AFCEE) by Parsons Engineering Science, Inc. (parsons ES) as an update to the Final Intrinsic Remediation Engineering Evaluation/Cost Analysis (EE/CA) for Underground Storage Tank (UST) Site 870, Hill Air Force Base (AFB), Utah (parsons ES, 1995). The EE/CA was conducted to evaluate the use of intrinsic remediation with long-term monitoring (LTM) for remediation of fuel hydrocarbon contamination dissolved in groundwater at UST Site 870. This update summarizes the results of the third sampling event performed as part of longterm groundwater monitoring at the site. This sampling was conducted …

A Consolidated Acs Flight Software Development Approach For The Earth Observing-1 Spacecraft , Kathie Blackman, Jeff D'Agostino

Small Satellite Conference

The Earth Observing 1 (EO-l) mission is part of NASA's New Millennium Program (NMP). The EO-l Attitude Control System (ACS) flight software was based on the Tropical Rainfall Measuring Mission (TRMM) flight software, both of which were developed by the Hammers Company, Inc. Lessons learned during TRMM ACS software development led to a consolidated software development approach for the EO-l ACS. The approach started with a standalone system that incorporated the ''first-cut'' flight software into the spacecraft simulation, allowing closed loop simulations to run on a desktop computer. Consequently, more algorithm and coding errors were detected earlier in the development …

Design, Construction And Testing Of A Voltage-Based Maximum Power Point Tracker (Vmppt) For Small Satellite Power Supply, Mohammad Masoum, Hooman Dehbonei

Small Satellite Conference

It is shown that at maximum power, the Photovoltaic (PV) voltage varies nonlinearily with temperature and isolation level, but is directly proportional to the PV cell open circuit voltage. The proportionality voltage-factor is fixed for a given PV generator regardless of temperature, isolation and panel configuration, but depends on cell material and manufacturing. This remarkable property is used to achieve temperature and insolation independent maximum power point tracking of satellite's solar cells with a simple and reliable technique. The open circuit voltage is continuously measured by a microcontroller and is used to estimate the maximum power operating point of the …

Spacecraft Computers On The Seastar Satellite, Sawat Tantiphanwadi

Small Satellite Conference

The SeaStar spacecraft requires a high performance computer system to handle its various requirements. It must process not only the high-rate data from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) instrument, but also the spacecraft ground interface system and the attitude control system data. This paper will describe the spacecraft computer architecture and its hardware. With minimum peripheral changes, the same computer can be configured to perform the payload, or the ground interface, or the attitude control functions. Each flight computer consists of three computer slices and a power module. There are two main flight computers on the SeaStar satellite; the …

Progress Toward Hydrogen Peroxide Micropropulsion, John Whitehead, Michael Dittman, Arno Ledebuhr

Small Satellite Conference

A new self-pressurizing propulsion system has liquid thrusters and gas jet attitude control without heavy gas storage vessels. A pump boosts the pressure of a small fraction of the hydrogen peroxide, so that reacted propellant can controllably pressurize its own source tank. The warm decomposition gas also powers the pump and is supplied to the attitude control jets. The system has been incorporated into a prototype microsatellite for terrestrial maneuvering tests. Additional progress includes preliminary testing of a bipropellant thruster, and storage of unstabilized hydrogen peroxide in small sealed tanks.

A Low Power Approach To Small Satellite Propulsion, Joe Cardin, Larry Mosher

Small Satellite Conference

Small Satellites are emerging as the preferred platform for a wide variety of earth orbit and even interplanetary missions. These spacecraft are, by their very nature, extremely limited in volume, mass and power. Existing fluid propulsion options are too large, costly and complex for many small satellite applications. In an attempt to address this problem the Applied Physics Laboratory of Johns Hopkins University, as part of an advanced development contract with NASA, has contracted with V ACCO Industries. The objective of this program is to conceive and demonstrate a cold gas propulsion system specifically designed for small satellites. Major design …

Low Cost Propulsion Development For Small Satellites At The Surrey Space Centre , Gary Haag, Martin Sweeting, Guy Richardson

Small Satellite Conference

The Surrey Space Centre (SSC) has led the way in demonstrating the utility of microsatellite size spacecraft for research, humanitarian, commercial, and military applications. SSC recognises that cost effective propulsion technology for small spacecraft is an enabling technology for expanding the utility of these assets and has been actively researching this field since 1993. This paper provides an overview of propulsion research and development at the Surrey Space Centre. The paper will summarise SSC goals for small spacecraft propulsion technology and link them to areas of propulsion research past, present and future. A review of Surrey's propulsion history to include …

A Maintenance-Free Battery Charge Control Approach For Nickel-Hydrogen Batteries, Andrew Lewin

Small Satellite Conference

The most common battery charging approaches for nickel-hydrogen batteries suffer from two key limitations. They either consistently under- or overcharge the battery or they require accurate knowledge of the battery capacity. For the ORBCOMM constellation of 36 small communications satellites, regular overcharging is unacceptable because it decreases battery life. Worse, the lost life occurs when the satellite constellation is facing its greatest usage demand. On the other hand, obtaining an accurate knowledge of the battery capacity requires an upfront effort to develop the necessary engineering tools and characterize battery performance. In addition, the satellite operator must bear the recurring expense …

Gyrowheel™ - An Innovative New Actuator/Sensor For 3-Axis Spacecraft Attitude Control , George Tyc, William Whitehead, Satya Pradhan, Douglas Staley, Cameron Ower, Jeff Cain, Michael Wiktowy

Small Satellite Conference

The Bristol Gyro Wheel is an innovative attitude control system device that provides both an angular momentum bias and control torques about three axes while at the same time measuring the spacecraft angular rates about two axes. The principles of operation of this device are explained and the flight model design is described that is targeted at small satellite applications which is currently under development. A fully functional prototype of the GyroWheel has been developed that has demonstrated the actuator and rate sensing capabilities and some of the test results are given. One of the key advantages of the Gyro …

Development Of Shape Memory Alloy (Sma) Actuated Mechanisms For Spacecraft Release Applications , Shawn Smith, David Dowen, Eugene Fossness, Andrew Peffer

Small Satellite Conference

Current methods of deploying spacecraft payloads typically employ explosive-type separation devices which do not address shock concerns and are not resettable without disassembly from the spacecraft or significant refurbishment of parts. Other separation mechanisms exist which eliminate explosives, but also do not offer reduced shock or the advantages of insitu resettability. Several new, shape-memory alloy (SMA) actuated release mechanisms have been developed for satellite release applications for loads of 500 lbf and greater. These mechanisms all offer fast, non-pyro releases and are completely testable and reusable while mounted on the spacecraft. The Qwknut and the Low-Force Nut (LFN) are suitable …

Adcs Of Thns-1 Nanosatellite With Off-Pointing Capability, Li Junfeng, You Zheng, Xu Min

Small Satellite Conference

One of the broad objectives of the THNS-1 nanosatellite, which mass will be less 5kg, is to demonstrate the availability of micro/nano-technology. The attitude control system has a three-axis magnetometer, four two-axis sun sensors and a MIMU for providing an attitude knowledge. The extended Kalman filter will be used for determining the attitude angles and attitude velocity. Three reaction wheels will be used to perform off-nadir pointing manoeuvres with magnetorquers for momentum dumping. A gravity gradient boom with top mass, which was successfully used on many microsatellites in the world, will be used for passive nadir pointing stabilisation.

An Attitude Control System For A Low-Cost Earth Observation Satellite With Orbit Maintenance Capability , Willem Steyn, Yoshi Hashida

Small Satellite Conference

UoSAT-12 is a low-cost minisatellite built by Surrey Satellite Technology Ltd. (SSTL), it is amongst other objectives also a technology demonstrator for high performance attitude control and orbit maintenance on a future constellation of earth observation satellites. The satellite uses a 3-axis reaction wheel configuration and a cold gas propulsion system to enable precise and fast control of its attitude, for example, during orbit manoeuvres. Magnetorquer coils assist the wheels mainly for momentum dumping. This paper describes the various attitude control modes required to support: 1) the initial attitude acquisition phase, 2) a high resolution imager payload during pointing and …

Space Testing Of The Advanced Instrument Controller, Todd Goforth, Scott Cannon, James Lyke

Small Satellite Conference

An extremely compact, low-power instrument controller and data processor system has been developed for space-based applications. Known as the Advanced Instrument Controller (AIC), this hybrid device contains both digital and analog components in a package less than 5 grams in weight and 2 x 3 em in size. Based on the Intel 8031151 microprocessor and implementing a superset of the 8051 instruction set, the AIC supports l28k of SRAM, 128k of EEPROM, four 8-bit parallel ports, six serial communications ports, 32 analog l2-bit AID channels, and eight D/A channels. Rugged (30k g) with a wide operating temperature range (-120 to …

New Approach To Achieving Stand Alone Gps Attitude Determination Using Dual Short Baselines For Small-Satellite , S. Purivigraipong, M. S. Hodgart, Y. Hashida, M. J. Unwin

Small Satellite Conference

This paper proposes a new approach to GPS (Global Positioning System) attitude determination for small satellite application in LEO (low Earth orbit). Prior knowledge of attitude and integer resolution is not required. The methodology of the new approach includes integer ambiguity search, initial estimation of attitude and line bias, attitude initialisation, path difference estimation and fine attitude determination. The observable is the carrier phase difference measurement between two GPS antennas. A dual short baseline (typical baseline length up to 30 cm) is assumed in this research. The key point to initialising attitude is to estimated the attitude of individual baseline …

High Speed, Low Weight Momentum/Reaction Wheels, Larry Wilhide, Louis Brothers, Eugene Breyer

Small Satellite Conference

Advancements in several critical areas have made possible lightweight, strong and highly reliable momentum / reaction wheels. The development of reliable bearings with design features that allow high speed operation for space flight applications has significantly altered the weight / speed / wheel design considerations. Current designs typically operate at speeds at or below 6,000 RPM The new retainerless can achieve speeds 10 times that and meet or improve all other significant bearing operating parameters. These bearings offer a design life of 20 years or greater and are free of retainer caused anomalies. The development and test of these bearings …

The Sprite Mini-Lift Vehicle: Performance, Cost, And Schedule Projections For The First Of The Scorpius™ Low-Cost Launch Vehicles, James Berry, Robert Conger, James Wertz

Small Satellite Conference

Scorpius™ is a Microcosm program, under two Phase III Small Business Innovation Research contracts at the Air Force Research Laboratory, Space Vehicles Directorate. The Scorpius™ program is to develop an entirely new launch vehicle family with the objective of reducing total launch cost by a factor of 5 to 10. This paper reports on status and substantial progress of the program since our last USU update. Specifically, the Sprite Mini-Lift Vehicle is projected to have a first DT &E tlight in the first quarter of 200 I and first production flight in the first quarter of 2002. It has a …