Digital Commons Network^™

A Satellite Link Analysis Tool For A Portable Ground Station, Capt. William Jackson

Small Satellite Conference

The product of this research effort is a comprehensive and integrated software package for the analysis of digital satellite links. The system is designed to run on the IBM PC, and would be a useful addition to any portable ground station based on a compatible personal computer. The system performs three basic classes of functions: satellite orbital analysis, antenna gain pattern plotting, and link analysis. The first class of functions includes the computation of such quantities as velocity, orbital period, and coverage area for satellites in circular and elliptical orbits. The second class of functions is concerned with plotting the …

The Integrated Housekeeping Unit: A Method Of Telemetry, Command And Control For Small Spacecraft, Gordon Hardman

Small Satellite Conference

In a small satellite environment where the total power budget for telemetry command, ranging and all satellite control functions is not to exceed 2 Watts rather focused measures must be taken to consolidate these functions. Since 1975 AMSAT has been developing the concept of the Integrated Housekeeping Unit (IHU) for this purpose. The IHU combines the traditional telemetry encoder and command decoder with a multi-tasking microcomputer so that this single module is capable of handling all spacecraft functions simultaneously. The nature of the orbit planned for the series of spacecraft for which this unit was developed results in a high …

Mission Design And Operations: Spartan-Halley As A Paradigm For Small Satellites, Alan Stern, J.G. Watzin, N. White

Small Satellite Conference

The SPARTAN reusable spacecraft opened a new arena for innovative scientific and engineering experimentation in low earth orbit. SPARTAN's a free flying, 3-axis inertially stabilized spacecraft which is deployed and retrieved by the Space Shuttle. The spacecraft is unique in that it performs all scientific observations as well as its guidance, navigation, and control functions completely autonomously. This paper will describe the innovative approach that was taken in the design of the SPARTAN guidance and navigation system for a 48-hour observation of Halley's Comet near perihelion passage. Autonomous vehicle navigation techniques that utilized solar sensors, a single star tracker, a …

System Design And Capabilities Of A Current Technology, Low-Cost, Small Satellite, J.R. Stuart, D.L. Taylor

Small Satellite Conference

Ball Aerospace, with its successful background and strong interest in low-cost lightweight satellites, is studying the designs of current technology satellites for a variety of launchers (e.g., STS/GAS, Pershing, Scout, Poseidon, Conestoga, Titan 11, ILV, and Delta II). Ball Aerospace has completed the design of a current technology, multi-mission, low-cost Scout-compatible satellite. This paper summarizes the system design features and capabilities of this Ball Scout Satellite (BSS). The BSS is designed to accommodate a wide range of Earth and celestially oriented missions, both spinning and 3-axis stabilized. The BSS design provides a marked improvement in payload support capabilities (mass, power, …

Nusat Ii - Manufacturing Design Of Lightweight Satellites, John Boyer Jr.

Small Satellite Conference

The successful flight of NUSAT I during 1985 and 1986 encouraged the Weber State College Center for Aerospace Technology (CAST) to continue developing other small satellites. This paper focuses on the mechanical design and construction of the NUSAT II space frame.

A Study For Semi-Passive Gravity Gradient Stabilization Of Small Satellites, Ali Siahpush, Andrew Sexton

Small Satellite Conference

This paper gives the results of a dynamical analysis of the Globesat gravity gradient stabilized satellite in a 500 km circular orbit. The linearized equations of motion are developed and the stability of the satellite is investigated. The satellite is equipped with magnetic torquers for the purpose of providing attitude correction torques. These correction torques can be used to effect large changes in orientation and for producing small impulses for damping residual librational motions. The analysis shows that such a satellite can be captured into a gravity gradient stabilized mode, and that residual motions can be damped to small steady …

"Bare Bones" Propulsion For Small, Low Cost Satellites, Richard Daniels

Small Satellite Conference

The radio amateur satellite community pioneered in the design, fabrication and launch of small, low-cost satellites. While these satellites became increasingly more sophisticated, they continued for years as piggyback passengers with no capability for orbital adjustment once released. Beginning with the Phase III spacecraft series an onboard propulsion capability was included permitting significant adjustments to the initial orbit. This paper describes the design of the propulsion modules of three Phase III spacecraft initially using a solid rocket motor and moving to a bi-propellant liquid propulsion system in following spacecraft. While the specific hardware and system design utilized may not be …

Scout/Crres, Patrick Cudmore

Small Satellite Conference

This paper describes a Scout-launched chemical release satellite that the Goddard Space Flight Center (GSFC) will design, fabricate, integrate, test, and qualify. This will be done using off-the-shelf components assembled to a NASA/GSFC-supplied spacecraft structure as follows: Four chemical release modules from the CRRES satellite (BASD), and Communications, data handling, and power systems from GLOMR (DSI). This satellite will also include flight electronic instrumentation that will measure electric and magnetic fields and particles, and will be furnished by TBD.

Secondary Electron Emission From Solids By Electron And Proton Bombardment, Jørgen Schou

Scanning Microscopy

In the present work the experimental features of secondary electron emission from solids are considered in view of the standard semiempirical theory as well as recent transport theory based on similar principles as sputtering theory. Electron as well as proton-induced secondary electron emission are included. The yield, the energy distribution and angular distribution of the secondaries, and the contribution from reflected electrons are compared with the predictions of the theories. The deficiencies in the semiempirical theory are discussed. The results of the transport theory depend on the dominant production mechanism for the internal secondaries, cascade multiplication or primary ionization only. …

Specific Factors, Unemployment, And Immiserizing Growth In A Small Open Economy, Anjana Bhattacharyya, Basudeb Biswas

Economic Research Institute Study Papers

The economic rationale of import-substituting strategy of development pursued by the majority of the developing countries has long been questioned. Apart from the familiar argument that tariff tends to discourage exports and hence, can be viewed as an export tax, there is the immiserization argument proposed by Professor Johnson. Within the framework of a two-factor two-commodity model, Johnson has shown that a small tariff-imposing country may suffer a welfare loss from an increase in the stock of resources or technological change if the growth is biased in favor of the importable sector so that it tends to magnify the distortion …

Hydraulic Model Studies Of Upper Stillwater Dam Stepped Spillway And Outlet Works, Engineering Research Center, U.S. Department Of The Interior, Bureau Of Reclamation

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

Concrete dam and part of the Bonneville Unit of the Central Utah Project, is located about 80 miles east of Salt Lake City, Utah (fig. 1). Upper Stillwater Reservoir will be used to regulate the flows of Rock Creek and South Fork of Rock Creek for release to the Strawberry Aqueduct. The reservoir water surface will be kept constant during the summer but will be lowered about 160 feet during fall and winter releases. The structural height of the dam is 285 feet. Its crest length is 2,800 feet at elevation 8175.5 feet with parapets to elevation 8180.0. The spillway, …

A Possible Site Of Calcium Regulation In Rat Exocrine Pancreas Cells: An X-Ray Microanalytical Study, Norbert Roos

Scanning Microscopy

We analysed four subcellular compartments in rat exocrine pancreas cells, zymogen granules, cytoplasm surrounding the zymogen granules, mitochondria and cytoplasm in the basal part of the cells for sodium, magnesium, phosphorus, sulfur, chlorine, potassium and calcium content, using ultrathin frozen-dried cryosections. The highest concentrations of calcium were measured in the zymogen granules and the surrounding apical part of the cell containing Golgi apparatus, smooth endoplasmic reticulum and condensing vacuoles.

Calcium concentrations in the basal part of the cells (mostly rough endoplasmic reticulum) were 60% lower than in the apical part of the cells. The lowest calcium concentrations were measured in …

Utah Science Vol. 48 No. 3, Fall 1987

Utah Science

114 GROWING OLD IN NORTHERN UTAH: AN EVALUATION OF SOCIAL SERVICES FOR THE ELDERLY Y. Kim. M. Wilson and S. Chiba How elderly residents of Cache and Box Elder counties view available services.

117 WILL IT PAY TO PROCESS VEGETABLES IN UTAH? D. L. Snyder. T. F. Glover. L. K. Bond. D. Bailey. J. C. Andersen. W. C. Lewis and H. H. Fullerton Economists say a multi-commodity processing facility might be economically Feasible, but it involves considerable economic risk.

124 EMPLOYMENT OPPORTUNITIES IN ORNAMENTAL HORTICULTURE AND AGRICULTURAL MECHANIZATION G.A.Long Results of a recent survey indicate there are plenty of job …

Clonal Foraging In Perennial Wheatgrasses: A Strategy For Exploiting Patchy Soil Nutrients, L. D. Humphrey, D. A. Pyke

Aspen Bibliography

1 Foraging by means of plasticity in placement of tillers in response to low- and high- nutrient patches was examined in the rhizomatous wheatgrass Elymus lanceolatus ssp. lanceolatus. Its ability to exploit soil nutrient patches was compared to that of the closely related but caespitose E. lanceolatus ssp. wawawaiensis. 2 Clones of 14 genets of each taxon were planted in boxes consisting of two 30 x 30 cm cells: the 'origin cell' where clones were planted, and the adjacent 'destination cell', with each cell containing soil with either low or high levels of nutrients. 3 The rhizomatous taxon, which can …

Proton-Induced X-Ray Emission Spectrometry In Archaeology, C. P. Swann, S. J. Fleming

Scanning Microscopy

Proton-induced x-ray emission (PIXE) spectrometry is fast developing a reputation as a powerful analytical tool in the study of a range of ancient materials, including bronze, iron, gold, glass, faience, and smelting slag. PIXE data allows determination of the primary constituents which would indicate their recipe of production and determine their bulk physical properties (e.g., color of a glass, brittleness in a metal), and of a wide range of trace elements which may indicate the source of raw material s from which an artifact was constituted. Over the past seven years, PIXE spectrometry's primary advantage over other recognized methods now …

Influence Of Cytomatrix Proteins On Water And On Ions In Cells, I. L. Cameron, G. D. Fullerton, N. K. R. Smith

Scanning Microscopy

This review concerns the influence that cytomatrix proteins have on the motional properties of water and on the major inorganic ions in cells. The techniques we used for study of water in cells and on the cytomatrix proteins include: pulsed NMR of water protons, quench cooled ice crystal imprint size, and osmotic behavior. The technique for study of ions involved use of electron-probe X-ray microanalysis of thin cryosections of cells. The cytomatrix was found to play the major role in determining the extent of hydration water in cells, The amount of hydration water varied greatly between cell types (e.g., lens …

Sertoli Cell Death By Apoptosis In The Immature Rat Testis Following X-Irradiation, David J. Allan, Glenda C. Gobé, Brian V. Harmon

Scanning Microscopy

The importance of the morphological study of cell death has recently been emphasized by the recognition that the ultrastructural features of dying cells allow categorization of the death as either apoptosis or necrosis. This classification enables inferences to be drawn about the mechanism and biological significance of the death occurring in a particular set of circumstances.

In this study, Sertoli cell death induced in the immature testis of three and four day old rats by 5 Gy (500 rads) x-irradiation was described by light and transmission electron microscopy with the objective of categorizing the death as apoptosis or necrosis. The …

Scanning Electron Microscopy Of Early Atherosclerosis In Rabbits Using Aortic Casts, Ralph G. Kratky, Margot R. Roach

Scanning Microscopy

Our research involves measuring the size and location of atherosclerotic lesions on the intimal surface of arteries. To this end we have developed a new method in which scanning electron micrographs of vascular casts with impressions of these lesions on their surface are used. This method is compared with light microscopy and scanning electron microscopy of tissue with lesions. All three methods are found to detect lesions equally well. We also examine the cellular elements in the lesion to determine how the images are formed.

The Versatility Of Scanning Electron Microscopy In Thin Film Device Analysis, D. J. Drake, W. G. Hawkins, R. W. Anderson

Scanning Microscopy

The versatility of scanning electron microscopy is shown for many stages of fabrication of thin film transistor driver matrices for actively addressed liquid crystal displays. Electron channeling and Schottky barrier charge collection modes allow rapid assessment of silicon crystal quality. The secondary electron mode allows examination of conductor lead crossover integrity. A form of voltage contrast is used on the completed array to monitor performance of the array prior to liquid crystal filling.

Image Simulation For Secondary Electron Micrographs In The Scanning Electron Microscope, David C. Joy

Scanning Microscopy

The interpretation of high resolution secondary electron images, and quantitative measurements of micrometer size features on integrated circuits, both require accurate modelling of the process of image formation in the scanning electron microscope. A Monte Carlo model, based on the semi-empirical theory of Salow, has been developed which permits the simultaneous computation of the secondary and backscattered yields. The physical constants necessary to apply this model can be derived from straightforward measurements of the total electron yield as a function of beam energy. On the basis of simplifying assumptions line profiles and images can then be simulated for specimens of …

Extension's Perspective Of Federal, State And Private Animal Damage Control Programs, Gary J. San Julian

Wildlife Damage Management Conference

Extension personnel are in a unique position to observe and to be involved in animal damage control (ADC) programs at the federal, state and private levels. In order to offer educational programs, we must interpret regulations and policies to provide a workable interface between ourselves, other agencies and the public. This is not an easy task in such a sensitive and emotional area.

Trophectoderm: The First Epithelium To Develop In The Mammalian Embryo, Lynn M. Wiley

Scanning Microscopy

The first epithelium to appear during mammalian embryogenesis is the trophectoderm, a polarized transporting single cell layer that comprises the wall of the blastocyst. The trophectoderm develops concurrently with blastocoele fluid production as the morula develops into a blastocyst. The process whereby the morula becomes a fluid-filled cyst is called 'cavitation', which can be regarded as the first functional expression of the trophectoderm phenotype. The outer layer of eel ls of the morula comprise the nascent trophectoderm and are already morphologically polarized prior to the onset of cavitation. A major working hypothesis in the field of mammalian embryogenesis is that …

Scanning Electron Microscopy And Electron Probe Microanalyses Of The Crystalline Components Of Human And Animal Dental Calculi, R. Z. Legeros, I. Orly, J. P. Legeros, C. Gomez, J. Kazimiroff, T. Tarpley, B. Kerebel

Scanning Microscopy

A review of the use of scanning electron microscopy (SEM) and electron probe microanalyses in the study of dental calculus showed that such studies provided confirmatory and supplementary data on the morphological features of human dental calculi but gave only limited information on the identity of the crystalline or inorganic components.

This study aimed to explore the potential of combined SEM and microanalyses in the identification of the crystalline components of the human and animal dental calculi. Human and animal calculi were analyzed. Identification of the crystalline components were made based on the combined information of the morphology (SEM) and …

Applications Of Transmission Electron Microscopy To Coal, C. A. Wert, K. C. Hsieh, Mike Buckentin, B. H. Tseng

Scanning Microscopy

Coal consists of a hydrocarbon matrix in which minerals are embedded. The hydrocarbon matter also contains impurities distributed as individual atoms. Thus, coal has phases similar to those in metallic or ceramic alloy systems; a matrix, included precipitates and atoms distributed individually in solid solution. Consequently, techniques of electron microscopy developed to examine metallic and ceramic alloy systems are directly applicable to coal. We report application of microanalytical techniques of electron microscopy to coal using examples of measurements for several coals. Identification and characterization of clays and sulfides is described. Use of x-ray emission spectroscopy for organic element measurement is …

The Bulk Specimen X-Ray Microanalysis Of Freeze-Fractured, Freeze-Dried Tissues In Gerontological Research, I. Zs.-Nagy

Scanning Microscopy

The rationale for choosing the freeze-fracture freeze-drying (FFFD) method of biological bulk specimen preparation as well as the theoretical and practical problems of this method are treated. FFFD specimens are suitable for quantitative X-ray microanalysis of biologically relevant elements. Although the spatial resolution of this analytical technique is low, the application of properly selected bulk standard crystals as well as the measurement of the intracellular water and dry mass content by means of another method developed in the same laboratory, allow us to obtain useful information about the age-dependent changes of ionic composition in the main intracellular compartments. The paper …

Response Of Mouse Lung Air-Blood Barrier To X-Irradiation: Ultrastructural And Stereological Analysis, L. De Saint-Georges, U. Van Gorp, J. R. Maisin

Scanning Microscopy

Male mice of the Balb/c strain were exposed, at an age of three months, to a single dose of 10 or 20 Gy on the right hemithorax. At 3, 4, 6, 9 and 12 months after exposure, lungs were processed for electron microscopy following a standardized procedure in order to allow stereological analysis. By this method, the arithmetical mean thickness and, the air-blood barrier mean thickness in the lung parenchyma was shown to increase quickly with time by oedemization and fibrinization of the septal space. The ratio endothelium/epithelium surfaces (Sr/SF) gradually decreased by reduction of both surfaces but this was …

Impurity Lattice And Sublattice Location By Electron Channeling, S. J. Pennycook

Scanning Microscopy

A new formulation is presented for the use of crystallographic orientation effects in electron scattering to determine impurity lattice location. The development of electron channeling techniques is reviewed and compared to high energy ion channeling and to the Borrmann effect in x-ray diffraction. The advantages of axial over planar geometry are discussed. Delocalization effects are more serious for quantitative analysis than have generally been believed. The new formulation applies to any crystal lattice and quantitatively includes delocalization effects via c-factors, which have been experimentally determined for diamond structure semiconductors. For sublattice site location this formulation removes the two major approximations …

Electron Beam Testing Of Passivated Devices Via Capacitive Coupling Voltage Contrast, W. Reiners, K. D. Herrman, E. Kubalek

Scanning Microscopy

By fundamental experiments and theoretical treatments a detailed understanding of the capacitive coupling voltage contrast {CCVC) has been gained, demonstrating that this technique is, in principle, applicable to a non-destructive testing of passivated integrated circuits (IC) by means of electron beams. In fact, however, several problems have to be eliminated in order to introduce this testing technique into a production line procedure.

In a first step, preconditions have to be met. These are a primary electron (PE) energy where the electron yield is greater than one and a sufficiently low extraction field above the IC. Secondly, as CCVC vanishes within …

Advanced Scanning Electron Microscopy Methods And Applications To Integrated Circuit Failure Analysis, E. I. Cole Jr., C. R. Bagnell Jr., B. G. Davies, A. M. Neacsu, W. V. Oxford, R. H. Propst

Scanning Microscopy

Semiconductor device failure analysis using the scanning electron microscope (SEM) has become a standard component of integrated circuit fabrication. Improvements in SEM capabilities and in digital imaging and processing have advanced standard acquisition modes and have promoted new failure analysis methods. The physical basis of various data acquisition modes, both standard and new, and their implementation on a computer controlled SEM image acquisition/processing system are discussed, emphasizing the advantages of each method. Design considerations for an integrated, online failure analysis system are also described. Recent developments in the integration of the information provided by electron beam analysis, conventional integrated circuit …

X-Ray Microanalysis Of Dentin: A Review, E. Hals, A. B. Tveit, B. Tøtdal

Scanning Microscopy

The aim of this review was to present a condensed summary of the literature on X-ray microanalysis of dentin, including both energy-dispersive (EDS) and wavelength-dispersive (WDS) analysis. Estimations of concentrations by XMA of dentin should be regarded as semiquantitative values. The Ca level in rat odontoblasts was elevated in the secreting end of the cell body. In predentin Ca accumulated at a concentration of 2% that of mineralized dentin. In coronal dentin the peritubular areas were hypermineralized (Ca, P, Mg). Primary caries lesions showed a decrease of Ca, P, Mg and Cl, and usually an increase of S and Zn. …