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Computation Of Scanning Tunneling Microscope Images Of Nanometer-Sized Objects Physisorbed On Metal Surfaces, J. P. Vigneron, I. Derycke, Th. Laloyaux, Ph. Lambin, A. A. Lucas

Scanning Microscopy

This communication deals with the application of a transfer-matrix strategy for the quantitative evaluation of the tunnel current in a scanning tunneling microscope (STM). The image given by a simple atomic-size object deposited on a metal surface is specifically examined in both modes of STM operation namely the constant-height and the constant-current modes. The two-dimensional corrugation induced at low temperature by Xe atoms physisorbed on an otherwise clean, unreconstructed Ni (110) surface is studied in detail. It is shown that the simple consideration of the elastic scattering of electrons by the three-dimensional potential barrier between the tip and the metal …

In-Vivo Reactions In Some Bioactive Glasses And Glass-Ceramics Granules, A. M. Gatti, T. Yamamuro, L. L. Hench, O. H. Andersson

Cells and Materials

Two different bioactive glasses and one glass-ceramic were implanted as granules for 2 months in rabbit muscle and for 5 months in sheep jaw in order to study the influence of the biological surroundings on the reactions of the materials.

Scanning electron microscope and energy dispersive X-ray microanalysis showed that a calcium and phosphorous-rich (CaP) surface layer (adjacent to a silicon rich-layer) forms on both glasses in both implantation sites. The glass-ceramic developed only a CaP layer. A chemical process of degradation was more evident in muscle, even though the implantation time was shorter than that in bone. For all …

Composition And Microstructure Of Commercial Full-Fat And Low-Fat Cheeses, V. V. Mistry, D. L. Anderson

Food Structure

The objective of this study was to analyze the composition of commercial full-fat and low-fat cheeses and to evaluate their microstructure. Commercial cheeses evaluated included full-fat and low-fat Cheddar, Mozzarella , processed, and Swiss cheeses. Cheddar cheeses ranged from 8.2% fat and 5 1.1% moisture in the 75% low-fat product to 33.2% fat and 35.9% moisture in the full-fat cheese . Mozzarella cheeses ranged in fat from a low of 2. I% to a high of 24% with corresponding moisture content of 56.6 to 45.5% respectively. Fatfree processed cheese had 0. 9% fat and 58.7% moisture , while the full …

Development Of The Food Microscopist, D. F. Lewis

Food Structure

This paper describes the processes through which the food microscopist develops his/her skills. It is based around a framework of Shakespeare's seven ages of man. The first stage is learning about equipment: how it works and how not to abuse it. Next, attention turns to how to prepare samples for examination whilst maintaining the validity of the observations and avoiding damage to the instrument. The "Lover" is the time at which an understanding of the basic structures of food products is gained and the "Soldier " starts to interpret these structures in terms of the performance of the foodstuff. Next, …

Properties Of Irradiated Starches, A. S. Sokhey, M. A. Hanna

Food Structure

Properties of irradiated starches have been outlined in this review . ')' -radiation generates free radicals on starch molecules which cause changes in starch properties . The intensity of free radicals is dependent upon starch moisture content , and temperature and duration of storage. Increasing dosages of -y-irradiation creates in creasing intensities of free radicals on carbohydrates. These free radicals are responsible for bringing about molecular changes and fragmentation of starch molec ules. Increasing ')' -irradiation dosages cause an in crease in acidity , and decreases in viscosity and water solubility of starches. The granule structure remains visually undamaged at …

An Overview Of The Role Of Fat In Nutrition And Formulation And Its Measurement In The Live Animal, Meat Carcass And Processed Meat Products, Paul B. Newman

Food Structure

The role of fat in nutrition and health is complex but one about which consumers have only recently become aware. As a consequence of changing consumer attitudes and because fat affects many physical attributes in food, raw material suppliers and food manufacturers have attempted to improve the range and nutritional composition of available foodstuffs. However, with a substantial price difference between fat and lean, and ever-increasing demands for improved throughputs and operational cost performance, producer and manufacturing sectors require rapid, accurate methods of fat measurement suitable for commercial application. These are only just beginning to become available but should ultimately …

The Structure Of Urinary Catheter Encrusting Bacterial Biofilms, D. J. Stickler, J. King, J. Nettleton, C. Winters

Cells and Materials

A major complication of long-term urethral catheterization is catheter blockage by encrustation. We have examined 20 encrusted catheters and in each case crystal formation was associated with the presence of bacterial biofilms on the luminal surfaces. Scanning electron microscopy and X-ray microanalysis indicated the presence of struvite and hydroxyapatite in the biofilms. Urease producing bacteria were colonizing 16 of the catheters. Proteus mirabilis was the commonest species being recovered from ten of the catheters. These results support the hypothesis that catheter encrustation has a similar etiology to that of infection-induced urinary stones and confirm that the important target for any …

Mineralization Of An Axially Aligned Collagenous Matrix: A Morphological Study, D. L. Christiansen, F. H. Silver

Cells and Materials

Bone can be described as a highly ordered composite of type I collagen integrated with an inorganic mineral phase. In vitro models of bone mineralization using collagenous substrates have been reported in the literature. This study reports an in vitro system of mineralized reconstituted collagen fibers, with aligned fibrillar substructure. The collagen fibers were mineralized in a double diffusion chamber saturated with respect to calcium and phosphate. The morphology and ultrastructure of the mineral precipitate were evaluated as a function of the pH of the incubating media. Brushite crystal was observed at acidic pH. Large rectangular crystals formed at pH …

Immunocytochemical And Lectin-Gold Characterization Of The Interface Between Alveolar Bone And Implanted Hydroxyapatite In The Rat, H. Kawaguchi, M. D. Mckee, H. Okamoto, A. Nanci

Cells and Materials

The tissue response to implanted hydroxyapatite (HAP) in rat alveolar bone was investigated using morphological and cytochemical approaches. High-resolution immunogold labeling was used to examine the distribution of two non-collagenous bone proteins, osteopontin and osteocalcin, and two plasma proteins, a2HSglycoprotein (fetuin) and albumin. Glycoconjugates were characterized by lectin-gold cytochemistry using Ricinus communis I agglutinin and Wheat germ agglutinin. Transmission electron microscopy demonstrated the presence of an electron-dense, lamina limitans-like layer at the HAP particle-bone interface and organic material within the micropores of the particles. Mineral was observed in relation to both these sites. The HAP particle-bone interface was strongly …

Monte Carlo Simulation Of X-Ray Spectra From Rh- And Cu-Targets Generated By Kv-Electrons, K. Araki, Y. Kimura, R. Shimizu

Scanning Microscopy

Monte Carlo simulation is applied to calculate X-ray generation in thick targets under kV electron bombardment. As a preliminary examination, we adopted the simple model based on the uses of: (1) screened Rutherford scattering formula and Bethe's stopping power for describing elastic scattering and energy loss process of penetrating electrons, respectively, (2) Burhop's ionization-cross-section and Sommerfeld's Bremsstrahlung equation for generation of characteristic and continuous X-rays, respectively. In the Monte Carlo simulation, however, more practical expressions were used for convenience of calculation to describe generation of X-rays.

To see how precisely this Monte Carlo simulation describes X-ray spectrum generated in a …

Spectral Decomposition Of Wavelength Dispersive X-Ray Spectra: Implications For Quantitative Analysis In The Electron Probe Microanalyzer, G. Remond, J. L. Campbell, R. H. Packwood, M. Fialin

Scanning Microscopy

The line shapes of Kα, Lα,β and Mα X-ray peaks of pure elements were analyzed by means of commercial wavelength dispersive spectrometers (WDS) attached to an electron probe micro-analyzer (EPMA). A pseudo-Voigt function, i.e., a linear combination of Gaussian and Lorentzian distributions, was used as a fitting profile for the X-ray peaks, with Gaussian offsets incorporated in the short wavelength (high energy) side to describe the observed asymmetry.

The asymmetry of X-ray peaks resulting from both instrumental distortions and satellite bands may lead to discrepancies in quantitative analysis with the EPMA as a function of the procedure used for deriving …

The Russian Wheat Aphid In Utah, Jay B. Karren

All Archived Publications

No abstract provided.

Evaluation Of Roadside Stabilization And Beautification Plantings In South-Central Utah, United States Department Of Agriculture, Forest Service

Plants

Numerous roadside plantings at semiarid sites in the south-central Utah counties of Juab, Sanpete, and Sevier were intended to stabilize roadsides with plants harmonizing with natural vegetation. The plantings, originally for demonstration, began in the 1950's. They included bareroot transplants and direct seedings. Soils and geologic substrates at six sites were analyzed for 15 characteristics. Plant performance and survival was summarized for 37 sites. Thirty species established well by direct seeding and 62 species established well from transplants. Numerous other species have also persisted at the planting sites but are not as vigorous or as well adapted. Direct seedings were …

Diamond Mountain Resource Area Resource Management Plan And Environmental Impact Statement, United States Bureau Of Land Management

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

This proposed resource management plan and final environmental impact statement addresses management of all resources on approximately 709,000 acres of public land administered by the Bureau of Land Management, Diamond Mountain Resource Area, Vernal District, in Daggett, Duchesne, and portions of Uintah Counties, in northeastern Utah.

Rangeland Monitoring: Analysis, Interpretation, And Evaluation, United States Bureau Of Land Management

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

The collection of monitoring data results in quantitative and qualitative information obtained from measurements or estimates of the natural resources. These data are most valuable when their meaning is defined and presented in understandable terms to the resource manager. This is the analysis, interpretation, and evaluation process. The result is the documentation of conclusions on the progress of management to accomplish specific management objectives. Such conclusions are used for management and planning purposes, and in particular, for determining managment actions and establishing new or revised management objectives.

Archeological Investigations At Two Sites In Dinosaur National Monument: 42un1724 And 5mf2645, United States Department Of The Interior National Park Service

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

Archeological excavations in Dinosaur National Monument (DINO) were conducted at 5MF2645 (the Pool Creek Site) in 1988 and 42UN1724 (Juniper Ledge Shelter) in 1989. The information from these two sites, along with additional archeological data obtained between 1988 and 1992, have expanded our knowledge of the past 3700 years of human occupation in the DINO area. Juniper Ledge Shelter (42UN1724) is a south-southeast facing rockshelter in the Jones Hole Ely Creek area of the monument. Excavation of a two meter square unit produced evidence of three occupational components and a Fremont burial of an adult female with associated artifacts. The …

Overview Of The Proposed Critical Habitat For The Colorado River Endangered Fishes, United States Department Of The Interior Fish And Wildlife Service

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

This document presents an overview of the process, procedures and determinations associated with the proposed critical habitat designation for the razorback sucker, Colorado squawfish, humpback chub, and bonytail (also known as bonytail chub). These species are listed as endangered under the Endangered Species Act (Act) of 1973, as amended (16 U.S.C. 1531 et seq.). Part I is an overview of the proposed critical habitat designation for the Colorado River endangered fishes. Part II is a summary of the biological information used in determining areas for proposed designation and the description of each area proposed on January 29, 1993 (58 FR …

A Prairie Dog Abatement Program In San Juan County, Utah, Terry A. Messmer, Jim Keyes, Roy Mcdonald

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

Four species of prairie dogs are native to the plains and plateaus of the western United States. The most abundant and widely distributed of these is the blacktailed prairie dog, (Cynomys ludovicianus). This species has been a frequent topic of discussion at previous Great Plains Wildlife Damage Control workshops. Black-tailed prairie dog ecology and management was the topic of a panel discussion held at the Fifth Great Plains Wildlife Damage Control Workshop, in Lincoln, Nebraska (Timm and Johnson 1982) and the theme topic at the Eighth Great Plains Wildlife Damage Control Workshop in Rapid City, South Dakota (Uresk et al. …

Big Eightmile, North Fork Of Timber And Alder Creek Timber Sale Final Environmental Impact Statement, United States Forest Service

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

This Final Environmental Impact Statement documents the analysis of nine alternatives, including a "no action" alternative, that were developed for the proposed Big Eightmile, North Fork Timber, and Alder Creeks Timber Sales. The proposed action is designed to help achieve the silvicultural goals and objectives of the 1988 Salmon National Forest Land and Resource Management Plan (Forest Plan). Each alternative responds to issues associated with the proposed action that were identified during the scoping processes both preceding and following the Draft Environmental Impact Statement.

Archeological Investigations At Two Sites In Dinosaur National Monument: 42un1724 And 5mf2645, James A. Truesdale, National Park Service

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

Archeological excavations in Dinosaur National Monument (DINO) were conducted at 5MF2645 (the Pool Creek Site) in 1988 and 42UN1724 (Juniper Ledge Shelter) in 1989. The information from these two sites, along with archeological data obtained between 1988 and 1992, have expanded our knowledge of the past 3700 years of human occupation in the DINO area. Juniper Ledge Shelter is a south-southeast facing rockshelter in the Jones Hole Ely Creek area of the monument. Excavation of a two meter square unit produced evidence of three occupational components and a Fremont burial of an adult female with associated artifacts. The upper two …

Electron Probe X-Ray Microanalysis Applied To Thin Surface Films And Stratified Specimens, J. L. Pouchou, F. Pichoir

Scanning Microscopy

The basic principles of X-ray microanalysis of thin surface films and stratified targets are summarized. The influence of the electron beam accelerating voltage on the analyzed depth is discussed. It is shown that in the field of soft X-rays, the effective depth of analysis is most often limited by the absorption of the radiation in the specimen itself. For high energy radiations, the importance of the secondary emission due to fluorescence excited by the continuous radiation and by the characteristic lines is outlined. The main concepts of the recent ø(ρz) models used for quantitation in the recent software packages are …

Environmental Assessment, Proposed Predatory Animal Damage Control On Public Lands In Sweetwater, Lincoln, Uinta, And Sublette Counties, Wyoming, United States Department Of The Interior Bureau Of Land Management

Environmental Assessments (WY)

This Environmental Assessment is prepared by the Bureau of Land Management (BLM), Rock Springs District with the cooperative participation of the U.S. Department of Agriculture, Animal and Plant Health Inspection Service, Animal Damage Control Unit (USDA-APHIS-ADC, hereafter referred to as APHIS-ADC). This environmental assessment documents the environmental impact analysis of the APHIS-ADC ongoing and proposed program of predatory animal damage control for the protection of domestic livestock and wildlife within the BLM Rock Springs District. The environmental assessment analyzes the impacts associated with the full range of animal damage control activities included in the APHIS-ADC proposed Predatory Animal Damage Control …

Final Oil And Gas Leasing Environmental Impact Statement [Microform] : Grand Mesa, Uncompahgre And Gunnison National Forests V2, United States Forest Service

Environmental Assessments (NV)

No abstract provided.

Assassin Bug, Alan H. Roe

All Archived Publications

No abstract provided.

Vascular Flora And Vegetation Of Capitol Reef National Park, Utah, Kenneth D. Heil, J. Mark Porter, Rich Fleming, William H. Romme

Elusive Documents

No abstract provided.

Preserves At Risk: An Investigation Of Resource Management Strategies, Implications And Opportunities, R. J. Lilieholm

Elusive Documents

Human activities already threaten the globe's physical and biological systems. Worldwide, species extinction rates are estimated to be one thousand times what they would be in the absence of human activity (Wilson 1988). Raven (1988) estimates that 25% of the world's plant and animal species existing in 1985 may be extinct by 2015, with most extinctions occurring in tropical regions. While these extinction rates are staggering, global warming would greatly accelerate extinction rates that some scientists believe may already exceed those accompanying the decline of the dinosaurs 65 million years ago (Wolf 1987).

A Few Steps Towards A More Quantitative Understanding Of Contrast In The Scanning Electron Microscope, F. Hasselbach, U. Maier

Scanning Microscopy

The interaction volume of the electron beam with the specimen in a scanning electron microscope (SEM) is a highly complex function of the surface structure of the specimen, its chemical composition and the energy of the scanning electron beam.· The video signals formed by secondary electrons (SE) or backscattered electrons (BSE) reflect this complexity insofar as they may contain not only information of the interior of the pixel which has just been scanned and its neighborhood, but may depend on surface details hundreds of microns apart from the impinging point of the electron beam. This leads to artifacts in scanning …

Applications Of Charge Collection Microscopy: Electron-Beam-Induced Current To Semiconductor Materials And Device Research, Richard J. Matson

Scanning Microscopy

Among all of the possible techniques for the micro-characterization of semiconductor materials and devices in a scanning electron microscope (SEM), charge collection microscopy (CCM), more commonly known as electron-beam-induced current (EBIC), is probably both the most easily deployed and the most versatile characterization technique. Following a brief review of the basic theory of the generation and detection of the EBIC signals, various techniques and applications to the micro-characterization of experimental semiconductor materials and devices will be presented. The applications are primarily to emerging photovoltaic materials and devices. This report is not in any way intended as a complete overview of …

Synchrotron Radiation Induced X-Ray Microanalysis: A Realistic Alternative For Electron- And Ion-Beam Microscopy?, K. Janssens, F. C. Adams, M. L. Rivers, K. W. Jones

Scanning Microscopy

Synchrotron radiation induced X-ray micro fluorescence analysis (μ-SRXRF) is compared with more conventional microanalytical techniques such as secondary ion microscopy (SIMS) and electron probe X-ray microanalysis (EPXMA) for two typical microanalytical applications. μ-SRXRF and EPXMA are employed for the analysis of individual particles, showing the complementary character of both techniques. By means of element mapping of trace constituents in a heterogeneous feldspar material, the strong and weak points of μ-SRXRF in comparison to EPXMA and SIMS are illustrated. The most striking difference between μ-SRXRF and the other two microanalytical methods is the ability of SRXRF to probe deep into the …

Influence Of Primary Electron Beam Angle Of Incidence On Auger Electron Spectra, Mark A. Smith

Scanning Microscopy

A principal step in the extraction of Auger electron yields and line shapes from electron-excited spectra is an understanding of the attendant electron background. Experiments are reported here in which the influence of the primary electron beam angle of incidence on Auger spectral backgrounds has been separated from that of the angle of electron emission. The secondary electron background for clean polycrystalline palladium, on the high-energy side of the MNN peaks, have been studied as functions of primary beam angle of incidence and beam energy. For the range of beam energies investigated, < 10 keV, linearization of the secondary cascade is easily observed in log-log plots of intensity versus energy. When cascades are fitted with Sickafus-type functions, AE^-m (E = electron energy), the parameter m …