Science.gov

Sample records for mineral electronic components

  1. Electron microprobe mineral analysis guide

    NASA Technical Reports Server (NTRS)

    Brown, R. W.

    1980-01-01

    Electron microprobe mineral analysis guide is a compilation of X-ray tables and spectra recorded from various mineral matrices. Spectra were obtained using electron microprobe, equipped with LiF geared, curved crystal X-ray spectrometers, utilizing typical analytical operating conditions: 15 Kv acceleration potential, 0.02 microampere sample current as measured on a clinopyroxene standard (CP19). Tables and spectra are presented for the majority of elements, fluorine through uranium, occurring in mineral samples from lunar, meteoritic and terrestrial sources. Tables for each element contain relevant analytical information, i.e., analyzing crystal, X-ray peak, background and relative intensity information, X-ray interferences and a section containing notes on the measurement. Originally intended to cover silicates and oxide minerals the tables and spectra have been expanded to cover other mineral phases. Electron microprobe mineral analysis guide is intended as a spectral base to which additional spectra can be added as the analyst encounters new mineral matrices.

  2. Electronic Component Obsolescence

    SciTech Connect

    Sohns, Carl William; Ward, Christina D

    2010-01-01

    Electronic component obsolescence occurs when parts are no longer available to support the manufacture and/or repair of equipment still in service. Future instrumentation containing complex components WILL face obsolescence issues as technology advances. This paper describes hardware and software obsolescence as well as factors to consider when designing new instrumentation.

  3. Cooling system for electronic components

    DOEpatents

    Anderl, William James; Colgan, Evan George; Gerken, James Dorance; Marroquin, Christopher Michael; Tian, Shurong

    2016-05-17

    Embodiments of the present invention provide for non interruptive fluid cooling of an electronic enclosure. One or more electronic component packages may be removable from a circuit card having a fluid flow system. When installed, the electronic component packages are coincident to and in a thermal relationship with the fluid flow system. If a particular electronic component package becomes non-functional, it may be removed from the electronic enclosure without affecting either the fluid flow system or other neighboring electronic component packages.

  4. Cooling system for electronic components

    SciTech Connect

    Anderl, William James; Colgan, Evan George; Gerken, James Dorance; Marroquin, Christopher Michael; Tian, Shurong

    2015-12-15

    Embodiments of the present invention provide for non interruptive fluid cooling of an electronic enclosure. One or more electronic component packages may be removable from a circuit card having a fluid flow system. When installed, the electronic component packages are coincident to and in a thermal relationship with the fluid flow system. If a particular electronic component package becomes non-functional, it may be removed from the electronic enclosure without affecting either the fluid flow system or other neighboring electronic component packages.

  5. Advanced Power Electronics Components

    NASA Technical Reports Server (NTRS)

    Schwarze, Gene E.

    2004-01-01

    This paper will give a description and status of the Advanced Power Electronics Materials and Components Technology program being conducted by the NASA Glenn Research Center for future aerospace power applications. The focus of this research program is on the following: 1) New and/or significantly improved dielectric materials for the development of power capacitors with increased volumetric efficiency, energy density, and operating temperature. Materials being investigated include nanocrystalline and composite ceramic dielectrics and diamond-like carbon films; 2) New and/or significantly improved high frequency, high temperature, low loss soft magnetic materials for the development of transformers/inductors with increased power/energy density, electrical efficiency, and operating temperature. Materials being investigated include nanocrystalline and nanocomposite soft magnetic materials; 3) Packaged high temperature, high power density, high voltage, and low loss SiC diodes and switches. Development of high quality 4H- and 6H- SiC atomically smooth substrates to significantly improve device performance is a major emphasis of the SiC materials program; 4) Demonstration of high temperature (> 200 C) circuits using the components developed above.

  6. Modeling the electron strahl component

    NASA Astrophysics Data System (ADS)

    Nieves-Chinchilla, Teresa

    The electron velocity distribution functions in the solar wind consist of three different populations: core, halo and strahl. The core and halo are mainly responsible for the temperature and density. However, it has been suggested that the field-aligned strahl component could play an important role in the anisotropy, heat flux and fluctuating fluid velocity. In this work we have the following goals: a) develop a method to distinguish the strahl from the core and halo populations of the electron velocity distribution function; and, b) describe this component by modeling and fitting. To accomplish this, we use the high angular and energy resolution data of the Cluster/PEACE electron spectrometer.

  7. The mineralization of crystalline inorganic components in Japanese serow horn.

    PubMed

    Hashiguchi, K; Hashimoto, K

    1995-12-01

    The Japanese serow (Capricornis crispus) is protected as a special natural monument in Japan. The ring count of the soft X-ray photographs of Japanese serow horn was found to be a useful criteria to determine the ages exactly. The mineralization process in Japanese serow horn was examined microscopic, ICP and X-ray diffraction methods. The incremental lines appeared as light and dark layers in the section stained for fuchsin and methylen blue. Mineral depositions were observed among the keratin fibers, no matrix vesicle in the electron dense regions. X-ray diffraction pattern of crystalline inorganic components in Japanese serow horn was determined as beta-tricalcium phosphate (TCP), hydroxyapatite (HA) and unknown phase. ICP measurement was also carried out. The horn contained trace elements of K besides Na, Ca, Fe and P. The Ca/P molar was found to be 2.9. The ratio was much higher than the theoretical value of HA. Presumably, keratin was the seed which might be related to mineralization and higher Ca activity was detected in the initial phase of epitaxial growth. Analytical results of the measurement of trace elements in Japanese serow horn by using ICP method seemed to be correlated with the evaluation of environmental conditions. The present study indicated that the mineralization of Japanese serow horn directly related with deposition Ca-deficient HA among the keratin fibers.

  8. Thermoluminescence of the mineral components in granite

    SciTech Connect

    Schwartzman, R.G.; Kierstead, J.A.; Levy, P.W.

    1982-01-01

    The thermoluminescence (TL) of the minerals in Climax Stock (Nevada, USA) granite has been studied. The principal mineral constituents are plagioclase, quartz, potassium feldspar and biotite. Pyrite, sphene apatite and zircon occur at one percent or less. All exhibit TL except biotite. The TL kinetics were determined for plagioclase, quartz, potassium feldspar and pyrite. Plagioclase and potassium feldspar exhibit second order and pyrite first orker kinetics. Natural TL of quartz follows second order and artificial TL first order kinetics. However, in these four minerals unrealistic kinetic parameters are often obtained; thus more general kinetics, e.g. interactive kinetics, may apply. 8 figures.

  9. Automated cleaning of electronic components

    SciTech Connect

    Drotning, W.; Meirans, L.; Wapman, W.; Hwang, Y.; Koenig, L.; Petterson, B.

    1994-07-01

    Environmental and operator safety concerns are leading to the elimination of trichloroethylene and chlorofluorocarbon solvents in cleaning processes that remove rosin flux, organic and inorganic contamination, and particulates from electronic components. Present processes depend heavily on these solvents for manual spray cleaning of small components and subassemblies. Use of alternative solvent systems can lead to longer processing times and reduced quality. Automated spray cleaning can improve the quality of the cleaning process, thus enabling the productive use of environmentally conscious materials, while minimizing personnel exposure to hazardous materials. We describe the development of a prototype robotic system for cleaning electronic components in a spray cleaning workcell. An important feature of the prototype system is the capability to generate the robot paths and motions automatically from the CAD models of the part to be cleaned, and to embed cleaning process knowledge into the automatically programmed operations.

  10. Towards Prognostics for Electronics Components

    NASA Technical Reports Server (NTRS)

    Saha, Bhaskar; Celaya, Jose R.; Wysocki, Philip F.; Goebel, Kai F.

    2013-01-01

    Electronics components have an increasingly critical role in avionics systems and in the development of future aircraft systems. Prognostics of such components is becoming a very important research field as a result of the need to provide aircraft systems with system level health management information. This paper focuses on a prognostics application for electronics components within avionics systems, and in particular its application to an Isolated Gate Bipolar Transistor (IGBT). This application utilizes the remaining useful life prediction, accomplished by employing the particle filter framework, leveraging data from accelerated aging tests on IGBTs. These tests induced thermal-electrical overstresses by applying thermal cycling to the IGBT devices. In-situ state monitoring, including measurements of steady-state voltages and currents, electrical transients, and thermal transients are recorded and used as potential precursors of failure.

  11. Electronic Components Subsystems and Equipment: a Compilation

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Developments in electronic components, subsystems, and equipment are summarized. Topics discussed include integrated circuit components and techniques, circuit components and techniques, and cables and connectors.

  12. Automated cleaning of electronic components

    SciTech Connect

    Drotning, W.

    1994-03-01

    Environmental and operator safety concerns are leading to the elimination of trichloroethylene (TCE) and chlorofluorocarbon (CFC) solvents in electronic component cleaning processes that remove rosin flux, organic and inorganic contamination, and particulates. Present processes depend heavily on these solvents for manual spray cleaning of small components and subassemblies. Use of alternative solvent systems can lead to longer processing times and reduced quality. Automated spray cleaning can improve the quality of the cleaning process, thus enabling the productive use of environmentally conscious materials, while minimizing personnel exposure to hazardous materials. In addition, the use of robotic and automated systems can reduce the manual handling of parts that necessitates additional cleaning. We describe the development of a prototype robotic system for cleaning electronic components in a spray cleaning workcell. An important feature of the prototype system is the capability to generate the robot paths and motions automatically from the CAD models of the part to be cleaned, and to embed cleaning process knowledge into the automatically programmed operations.

  13. Analytical transmission electron microscopy in minerals processing

    SciTech Connect

    Fraser, H.L.; Hsieh, K.C.; Twigg, M.E.

    1981-01-01

    A review of the possibilities of performing microchemical analysis in thin sections using a combination of scanning transmission electron microscopy and energy dispersive spectroscopy of x-rays is given. Particular attention is paid to the factors that limit accurate analysis at the highest spatial resolution. As an example of the use of these techniques applied to a potential problem in minerals processing, the identification of pyrite and pyrrhotite particles in Illinois, Herrin number 6 coal is presented.

  14. Mineral components and anti-oxidant activities of tropical seaweeds

    NASA Astrophysics Data System (ADS)

    Takeshi, Suzuki; Yumiko, Yoshie-Stark; Joko, Santoso

    2005-07-01

    Seaweeds are known to hold substances of high nutritional value; they are the richest resources of minerals important to the biochemical reactions in the human body. Seaweeds also hold non-nutrient compounds like dietary fiber and polyphenols. However, there is not enough information on the mineral compounds of tropical seaweeds. Also we are interested in the antioxidant activities of seaweeds, especially those in the tropical area. In this study, Indonesian green, brown and red algae were used as experimental materials with their mineral components analyzed by using an atomic absorption spectrophotometer. The catechins and flavonoids of these seaweeds were extracted with methanol and analyzed by high performance liquid chromatography (HPLC); the antioxidant activities of these seaweeds were evaluated in a fish oil emulsion system. The mineral components of tropical seaweeds are dominated by calcium, potassium and sodium, as well as small amounts of copper, iron and zinc. A green alga usually contains epigallocatechin, gallocatechin, epigallocatechin gallate and catechin. However, catechin and its isomers are not found in some green and red algae. In the presence of a ferrous ion catalyst, all the methanol extracts from the seaweeds show significantly lower peroxide values of the emulsion than the control, and that of a green alga shows the strongest antioxidant activity. The highest chelation on ferrous ions is also found in the extract of this alga, which is significantly different from the other methanol extracts in both 3 and 24 h incubations.

  15. Carbon Nanotubes: Molecular Electronic Components

    NASA Technical Reports Server (NTRS)

    Srivastava, Deepak; Saini, Subhash; Menon, Madhu

    1997-01-01

    The carbon Nanotube junctions have recently emerged as excellent candidates for use as the building blocks in the formation of nanoscale molecular electronic networks. While the simple joint of two dissimilar tubes can be generated by the introduction of a pair of heptagon-pentagon defects in an otherwise perfect hexagonal graphene sheet, more complex joints require other mechanisms. In this work we explore structural characteristics of complex 3-point junctions of carbon nanotubes using a generalized tight-binding molecular-dynamics scheme. The study of pi-electron local densities of states (LDOS) of these junctions reveal many interesting features, most prominent among them being the defect-induced states in the gap.

  16. Extracellular electron transfer mechanisms between microorganisms and minerals.

    PubMed

    Shi, Liang; Dong, Hailiang; Reguera, Gemma; Beyenal, Haluk; Lu, Anhuai; Liu, Juan; Yu, Han-Qing; Fredrickson, James K

    2016-10-01

    Electrons can be transferred from microorganisms to multivalent metal ions that are associated with minerals and vice versa. As the microbial cell envelope is neither physically permeable to minerals nor electrically conductive, microorganisms have evolved strategies to exchange electrons with extracellular minerals. In this Review, we discuss the molecular mechanisms that underlie the ability of microorganisms to exchange electrons, such as c-type cytochromes and microbial nanowires, with extracellular minerals and with microorganisms of the same or different species. Microorganisms that have extracellular electron transfer capability can be used for biotechnological applications, including bioremediation, biomining and the production of biofuels and nanomaterials. PMID:27573579

  17. Extracellular electron transfer mechanisms between microorganisms and minerals.

    PubMed

    Shi, Liang; Dong, Hailiang; Reguera, Gemma; Beyenal, Haluk; Lu, Anhuai; Liu, Juan; Yu, Han-Qing; Fredrickson, James K

    2016-10-01

    Electrons can be transferred from microorganisms to multivalent metal ions that are associated with minerals and vice versa. As the microbial cell envelope is neither physically permeable to minerals nor electrically conductive, microorganisms have evolved strategies to exchange electrons with extracellular minerals. In this Review, we discuss the molecular mechanisms that underlie the ability of microorganisms to exchange electrons, such as c-type cytochromes and microbial nanowires, with extracellular minerals and with microorganisms of the same or different species. Microorganisms that have extracellular electron transfer capability can be used for biotechnological applications, including bioremediation, biomining and the production of biofuels and nanomaterials.

  18. Image analysis of electron micrographs relating to mineralization in calcifying cartilage: theoretical considerations.

    PubMed

    Hunziker, E B; Herrmann, W; Cruz-Orive, L M; Arsenault, A L

    1989-01-01

    Biological mineralization kis a cell-mediated process which is believed to be triggered by a "nucleating agent." Various matrix structures, such as matrix vesicles, collagen fibrils and macromolecules, have been claimed to be the source of this substance, since these components have been found by transmission electron microscopy (TEM) of thin sections to be associated with early mineral crystals. Systematic image analysis of the relationships revealed in electron micrographs between specific matrix components and early mineral deposits has shown that unequivocal image interpretation is not possible. This is due principally to the problems posed by overprojection and truncation phenomena, since the structures being analyzed lie within the same dimensional range as thin section thickness. Various examples are illustrated and discussed. The site at which mineral crystals are initially laid down thus cannot be identified with any matrix structure using thin section TEM. Possible technical approaches to resolve this problem of image analysis are discussed.

  19. Prognostics for Electronics Components of Avionics Systems

    NASA Technical Reports Server (NTRS)

    Celaya, Jose R.; Saha, Bhaskar; Wysocki, Philip F.; Goebel, Kai F.

    2009-01-01

    Electronics components have and increasingly critical role in avionics systems and for the development of future aircraft systems. Prognostics of such components is becoming a very important research filed as a result of the need to provide aircraft systems with system level health management. This paper reports on a prognostics application for electronics components of avionics systems, in particular, its application to the Isolated Gate Bipolar Transistor (IGBT). The remaining useful life prediction for the IGBT is based on the particle filter framework, leveraging data from an accelerated aging tests on IGBTs. The accelerated aging test provided thermal-electrical overstress by applying thermal cycling to the device. In-situ state monitoring, including measurements of the steady-state voltages and currents, electrical transients, and thermal transients are recorded and used as potential precursors of failure.

  20. Applications of scanning electron microscopy to the study of mineral matter in peat

    SciTech Connect

    Raymond, R. Jr.; Andrejko, M.J.; Bardin, S.W.

    1983-01-01

    Scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) have been used for in situ analysis of minerals in peats by combining methods for producing oriented microtome sections of peat with methods for critical point drying. The combined technique allows SEM analysis of the inorganic components and their associated botanical constituents, along with petrographic identification of the botanical constituents. In peat deposits with abundant fluvial- or marine-derived minerals, one may use the above technique and/or medium- or low-temperature ashing followed by x-ray diffraction to readily identify the various mineral components. However, in some freshwater environments the scarcity of non-silica minerals makes the above techniques impractical. By separating the inorganic residues from the peat, one can isolate the non-silica mineral matter in the SEM for analysis by EDS. Furthermore, such separation allows SEM analysis of features and textures of both silica and non-silica mineral particles that might otherwise be unidentifiable. Results indicate the occurrence of detritial minerals in both Okefenokee and Snuggedy Swamp peats, the presence of authigenic or diagenetic minerals growing within peats, and dissolution features on freshwater sponge spicules that may account for the absence of spicules in Tertiary lignites.

  1. Cryogenic Applications of Commercial Electronic Components

    NASA Technical Reports Server (NTRS)

    Buchanan, Ernest D.; Benford, Dominic J.; Forgione, Joshua B.; Moseley, S. Harvey; Wollack, Edward J.

    2012-01-01

    We have developed a range of techniques useful for constructing analog and digital circuits for operation in a liquid Helium environment (4.2K), using commercially available low power components. The challenges encountered in designing cryogenic electronics include finding components that can function usefully in the cold and possess low enough power dissipation so as not to heat the systems they are designed to measure. From design, test, and integration perspectives it is useful for components to operate similarly at room and cryogenic temperatures; however this is not a necessity. Some of the circuits presented here have been used successfully in the MUSTANG and in the GISMO camera to build a complete digital to analog multiplexer (which will be referred to as the Cryogenic Address Driver board). Many of the circuit elements described are of a more general nature rather than specific to the Cryogenic Address Driver board, and were studied as a part of a more comprehensive approach to addressing a larger set of cryogenic electronic needs.

  2. Cryogenic applications of commercial electronic components

    NASA Astrophysics Data System (ADS)

    Buchanan, Ernest D.; Benford, Dominic J.; Forgione, Joshua B.; Harvey Moseley, S.; Wollack, Edward J.

    2012-10-01

    We have developed a range of techniques useful for constructing analog and digital circuits for operation in a liquid Helium environment (4.2 K), using commercially available low power components. The challenges encountered in designing cryogenic electronics include finding components that can function usefully in the cold and possess low enough power dissipation so as not to heat the systems they are designed to measure. From design, test, and integration perspectives it is useful for components to operate similarly at room and cryogenic temperatures; however this is not a necessity. Some of the circuits presented here have been used successfully in the MUSTANG [1] and in the GISMO [2] camera to build a complete digital to analog multiplexer (which will be referred to as the Cryogenic Address Driver board). Many of the circuit elements described are of a more general nature rather than specific to the Cryogenic Address Driver board, and were studied as a part of a more comprehensive approach to addressing a larger set of cryogenic electronic needs.

  3. 21 CFR 11.200 - Electronic signature components and controls.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Electronic signature components and controls. 11... SERVICES GENERAL ELECTRONIC RECORDS; ELECTRONIC SIGNATURES Electronic Signatures § 11.200 Electronic signature components and controls. (a) Electronic signatures that are not based upon biometrics shall:...

  4. Imaging Cytoskeleton Components by Electron Microscopy

    PubMed Central

    Svitkina, Tatyana

    2016-01-01

    The cytoskeleton is a complex of detergent-insoluble components of the cytoplasm playing critical roles in cell motility, shape generation, and mechanical properties of a cell. Fibrillar polymers—actin filaments, microtubules, and intermediate filaments—are major constituents of the cytoskeleton, which constantly change their organization during cellular activities. The actin cytoskeleton is especially polymorphic, as actin filaments can form multiple higher order assemblies performing different functions. Structural information about cytoskeleton organization is critical for understanding its functions and mechanisms underlying various forms of cellular activity. Because of the nanometer-scale thickness of cytoskeletal fibers, electron microscopy (EM) is a key tool to determine the structure of the cytoskeleton. This article describes application of rotary shadowing (or metal replica) EM for visualization of the cytoskeleton. The procedure is applicable to thin cultured cells growing on glass coverslips and consists of detergent extraction of cells to expose their cytoskeleton, chemical fixation to provide stability, ethanol dehydration and critical point drying to preserve three-dimensionality, rotary shadowing with platinum to create contrast, and carbon coating to stabilize replicas. This technique provides easily interpretable three-dimensional images, in which individual cytoskeletal fibers are clearly resolved, and individual proteins can be identified by immunogold labeling. More importantly, replica EM is easily compatible with live cell imaging, so that one can correlate the dynamics of a cell or its components, e.g., expressed fluorescent proteins, with high resolution structural organization of the cytoskeleton in the same cell. PMID:26498781

  5. Imaging Cytoskeleton Components by Electron Microscopy

    PubMed Central

    Svitkina, Tatyana

    2010-01-01

    Summary The cytoskeleton is a complex of detergent-insoluble components of the cytoplasm playing critical roles in cell motility, shape generation, and mechanical properties of a cell. Fibrillar polymers-actin filaments, microtubules, and intermediate filaments- are major constituents of the cytoskeleton, which constantly change their organization during cellular activities. The actin cytoskeleton is especially polymorphic, as actin filaments can form multiple higher order assemblies performing different functions. Structural information about cytoskeleton organization is critical for understanding its functions and mechanisms underlying various forms of cellular activity. Because of the nanometer-scale thickness of cytoskeletal fibers, electron microscopy (EM) is a key tool to determine the structure of the cytoskeleton. This article describes application of rotary shadowing (or metal replica) EM for visualization of the cytoskeleton. The procedure is applicable to thin cultured cells growing on glass coverslips and consists of detergent extraction of cells to expose their cytoskeleton, chemical fixation to provide stability, ethanol dehydration and critical point drying to preserve three-dimensionality, rotary shadowing with platinum to create contrast, and carbon coating to stabilize replicas. This technique provides easily interpretable three-dimensional images, in which individual cytoskeletal fibers are clearly resolved, and individual proteins can be identified by immunogold labeling. More importantly, replica EM is easily compatible with live cell imaging, so that one can correlate the dynamics of a cell or its components, e.g., expressed fluorescent proteins, with high resolution structural organization of the cytoskeleton in the same cell. PMID:19768431

  6. Scanning electron microscopy of clays and clay minerals

    USGS Publications Warehouse

    Bohor, B.F.; Hughes, R.E.

    1971-01-01

    The scanning electron microscope (SEM) proves to be ideally suited for studying the configuration, texture, and fabric of clay samples. Growth mechanics of crystalline units-interpenetration and interlocking of crystallites, crystal habits, twinning, helical growth, and topotaxis-also are uniquely revealed by the SEM. Authigenic kaolins make up the bulk of the examples because their larger crystallite size, better crystallinity, and open texture make them more suited to examination by the SEM than most other clay mineral types. ?? 1971.

  7. Infrared Attenuated Total Reflectance Spectroscopy: An Innovative Strategy for Analyzing Mineral Components in Energy Relevant Systems

    PubMed Central

    Müller, Christian Menno; Pejcic, Bobby; Esteban, Lionel; Piane, Claudio Delle; Raven, Mark; Mizaikoff, Boris

    2014-01-01

    The direct qualitative and quantitative determination of mineral components in shale rocks is a problem that has not been satisfactorily resolved to date. Infrared spectroscopy (IR) is a non-destructive method frequently used in mineral identification, yet challenging due to the similarity of spectral features resulting from quartz, clay, and feldspar minerals. This study reports on a significant improvement of this methodology by combining infrared attenuated total reflection spectroscopy (IR-ATR) with partial least squares (PLS) regression techniques for classifying and quantifying various mineral components present in a number of different shale rocks. The developed multivariate classification model was calibrated using pure component mixtures of the most common shale minerals (i.e., kaolinite, illite, montmorillonite, calcite, and quartz). Using this model, the IR spectra of 11 real-world shale samples were analyzed and evaluated. Finally, the performance of the developed IR-ATR method was compared with results obtained via X-ray diffraction (XRD) analysis. PMID:25358261

  8. Pulmonary mineral dust. A study of ninety patients by electron microscopy, electron microanalysis, and electron microdiffraction.

    PubMed Central

    Berry, J. P.; Henoc, P.; Galle, P.; Pariente, R.

    1976-01-01

    The results of a study of 90 patients are presented. Intrapulmonary mineral deposits were characterized by electron diffraction and electron probe microanalysis. Using this method, pneumoconioses may be distinguidhed from other pneumopathies. In cases of pneumoconiosis, there exists a specific relationship between the etiology of the dust exposure and the crystallographic characteristics of the intrapulmonary deposits. The nature of the deposits may be indicative of a specific type of pneumoconiosis. This method is particularly useful in differentiating between asbestos bodies and ferruginous bodies. The value of the method in general and its importance in the study of pneumoconiosis are discussed. Images Figure 4 Figure 13 Figure 5 Figure 14 Figure 6 Figure 15 Figure 7 Figure 16 Figure 8 Figure 17 Figure 1 Figure 9 Figure 10 Figure 2 Figure 11 Figure 3 Figure 12 PMID:937507

  9. [The balneotherapeutic components of sulfide-containing mineral waters].

    PubMed

    Khutoryansky, V A; Gorshkov, A G

    2015-01-01

    It has been suggested in an early study that sulfanes may serve as a source of sulfur contained in hydrogen sulfide sources. We have performed derivatization of sulfanes, known to be present in the "Novonukutskaya" mineral water. The presence of polysulfanes in balneotherapeutic sulfide waters was confirmed by the HPLC-UV and chromato-mass spectrometric techniques. Derivatization of inorganic polysulfides was achieved by using the reaction with methyl iodide. It was shown that polysulfanes contained in the examined samples were metastable and disintegrated into So and H2S. Almost all molecular zero-valent sulfur was present in the form of S8. The application of HPLC allowed to determine the equilibrium concentration of molecular sulfur. The presence of the above compounds in therapeutic sulfide waters raises the question of the mechanism of their curative action. The authors hypothesize that it may be related to the high therapeutic potency of the substances obtained by steam distillation from the "Novonukutskaya" mineral water. PMID:26841531

  10. Transmission electron microscopy (TEM) study of minerals in coal

    SciTech Connect

    Hsieh, Kuang-Chien

    1982-01-01

    Minerals in eight coals from different mines were characterized in the micron-size range by using analytical transmission electron microscopy. Specimens were thinned by ion-milling wafers cut from these coals; a cold stage cooled by liquid nitrogen was used to reduce thermal degradation of the minerals by the ion-beam. Different mineral compounds were observed in different coals. The major minerals are clays, sulfides, oxides, carbonates and some minor-element-bearing phosphates. Clays (kaolinite, illite and others) have been most commonly found as either flat sheets or round globules. Iron sulfide was mostly found in the No. 5 and No. 6 coals from Illinois, distributed as massive polycrystals, as clusters of single crystals (framboids) or as isolated single crystals with size range down to some 0.25 microns. Other sulfides and some oxides were found in other coals with particle size as small as some 200 angstroms. Quartz, titanium oxides and many other carbonates and phosphate compounds were also characterized. Brief TEM work in the organic mass of coal was also introduced to study the nature of the coal macerals.

  11. JPL preferred parts list: Reliable electronic components

    NASA Technical Reports Server (NTRS)

    Covey, R. E.; Scott, W. R.; Hess, L. M.; Steffy, T. G.; Stott, F. R.

    1982-01-01

    The JPL Preferred Parts List was prepared to provide a basis for selection of electronic parts for JPL spacecraft programs. Supporting tests for the listed parts were designed to comply with specific spacecraft environmental requirements. The list tabulates the electronic, magnetic, and electromechanical parts applicable to all JPL electronic equipment wherein reliability is a major concern. The parts listed are revelant to equipment supplied by subcontractors as well as fabricated at the laboratory.

  12. Minerals

    MedlinePlus

    Minerals are important for your body to stay healthy. Your body uses minerals for many different jobs, including building bones, making ... regulating your heartbeat. There are two kinds of minerals: macrominerals and trace minerals. Macrominerals are minerals your ...

  13. Multilayer electronic component systems and methods of manufacture

    NASA Technical Reports Server (NTRS)

    Thompson, Dane (Inventor); Wang, Guoan (Inventor); Kingsley, Nickolas D. (Inventor); Papapolymerou, Ioannis (Inventor); Tentzeris, Emmanouil M. (Inventor); Bairavasubramanian, Ramanan (Inventor); DeJean, Gerald (Inventor); Li, RongLin (Inventor)

    2010-01-01

    Multilayer electronic component systems and methods of manufacture are provided. In this regard, an exemplary system comprises a first layer of liquid crystal polymer (LCP), first electronic components supported by the first layer, and a second layer of LCP. The first layer is attached to the second layer by thermal bonds. Additionally, at least a portion of the first electronic components are located between the first layer and the second layer.

  14. Quantitative determination of mineral types and abundances from reflectance spectra using principal components analysis

    NASA Technical Reports Server (NTRS)

    Smith, M. O.; Adams, J. B.; Johnson, P. E.

    1985-01-01

    A procedure was developed for analyzing remote reflectance spectra, including multispectral images, that quantifies parameters such as types of mineral mixtures, the abundances of mixed minerals, and particle sizes. Principal components analysis reduced the spectral dimensionality and allowed testing the uniqueness and validity of spectral mixing models. By analyzing variations in the overall spectral reflectance curves, the type of spectral mixture was identified, mineral abundances quantified and the effects of particle size identified. The results demonstrate an advantage in classification accuracy over classical forms of analysis that ignore effects of particle-size or mineral-mixture systematics on spectra. The approach is applicable to remote sensing data of planetary surfaces for quantitative determinations of mineral abundances.

  15. 21 CFR 11.200 - Electronic signature components and controls.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... system access, the first signing shall be executed using all electronic signature components; subsequent... not performed during a single, continuous period of controlled system access, each signing shall be... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Electronic signature components and controls....

  16. 21 CFR 11.200 - Electronic signature components and controls.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... system access, the first signing shall be executed using all electronic signature components; subsequent... not performed during a single, continuous period of controlled system access, each signing shall be... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Electronic signature components and controls....

  17. 21 CFR 11.200 - Electronic signature components and controls.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... system access, the first signing shall be executed using all electronic signature components; subsequent... not performed during a single, continuous period of controlled system access, each signing shall be... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Electronic signature components and controls....

  18. Electrical and electronic devices and components: A compilation

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Components and techniques which may be useful in the electronics industry are described. Topics discussed include transducer technology, printed-circuit technology, solid state devices, MOS transistors, Gunn device, microwave antennas, and position indicators.

  19. 21 CFR 11.200 - Electronic signature components and controls.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... signature components and controls. (a) Electronic signatures that are not based upon biometrics shall: (1... signatures based upon biometrics shall be designed to ensure that they cannot be used by anyone other...

  20. State of the mineral component of rat bone tissue during hypokinesia and the recovery period

    NASA Technical Reports Server (NTRS)

    Volozhin, A. I.; Stupakov, G. P.; Pavlova, M. N.; Muradov, I. S.

    1980-01-01

    Experiments were conducted on young growing rats. Hypokinesia lasting from 20 to 200 days caused retarded gain in weight and volume of the femur and delayed development of the cortical layer of the diaphysis. In contrast, the density of the cortical layer of the femoral diaphysis increased due to elevation of the mineral saturation of the bone tissue microstructures. Incorporation of Ca into the bone tissue in hypokinesia had a tendency to reduce. Partial normalization of the bone tissue mineral component occurred during a 20 day recovery period following hypokinesia.

  1. Fixture aids soldering of electronic components on circuit board

    NASA Technical Reports Server (NTRS)

    Ross, M. H.

    1966-01-01

    Spring clamp fixture holds small electronic components in a desired position while they are being soldered on a circuit board. The spring clamp is clipped on the edge of the circuit board and an adjustable spring-steel boom holds components against the board. The felt pad at the end of the boom is replaced with different attachments for other holding tasks.

  2. Magnetic beneficiation of highland and hi-Ti mare soils - Rock, mineral, and glassy components

    NASA Technical Reports Server (NTRS)

    Taylor, Lawrence A.; Oder, Robin R.

    1990-01-01

    The exploitation of lunar soil can provide valuable raw materials for in situ resource utilization at a lunar base. A study of magnetic characterization was undertaken of three mare and two highland soils obtained from NASA. Beneficiation of mare and highland soils by sizing and magnetic separation can effectively concentrate the important components of the soils (e.g., ilmenite, native Fe, plagioclase, and aggluminates). As a soil matures and the impact melts consume additional minerals and rocks, the modal percentage of the minerals will decrease. The 'normative' percentage will become much greater than the modal percentage. Therefore, greater efficiency of separation can be realized with the proper selection of maturity of the soil, as well as by secondary grinding to further liberate specific minerals from lithic fragments (e.g., ilmenite and plagioclase).

  3. The enabling technology for recovery of valued components from minerals in the upper and Mid Amur region

    SciTech Connect

    Sorokin, A.P.; Rimkevich, V.S.; Dem'yanova, L.P.; Artemenko, T.V.

    2009-05-15

    Based on the physico-technical operations involved in the mineral processing technologies, the optimal production conditions are found for refractory fiber materials, aluminium, silicium, their compounds and other valued components. Ecologically safe and efficient aggregate technologies are developed for recovery of valued components from nonmetallic minerals and anthracides (brown coals).

  4. Composition and method for removing photoresist materials from electronic components

    DOEpatents

    Davenhall, Leisa B.; Rubin, James B.; Taylor, Craig M.

    2005-01-25

    Composition and method for removing photoresist materials from electronic components. The composition is a mixture of at least one dense phase fluid and at least one dense phase fluid modifier. The method includes exposing a substrate to at least one pulse of the composition in a supercritical state to remove photoresist materials from the substrate.

  5. Composition and method for removing photoresist materials from electronic components

    DOEpatents

    Davenhall, Leisa B.; Rubin, James B.; Taylor, Craig M. V.

    2008-06-03

    Composition and method for removing photoresist materials from electronic components. The composition is a mixture of at least one dense phase fluid and at least one dense phase fluid modifier. The method includes exposing a substrate to at least one pulse of the composition in a supercritical state to remove photoresist materials from the substrate.

  6. Current Space Station Experiments Investigating Component Level Electronics Repair

    NASA Technical Reports Server (NTRS)

    Easton, John W.; Struk, Peter M.

    2010-01-01

    The Soldering in a Reduced Gravity Experiment (SoRGE) and Component Repair Experiment (CRE)-1 are tests performed on the International Space Station to determine the techniques, tools, and training necessary to allow future crews to perform manual electronics repairs at the component level. SoRGE provides information on the formation and internal structure of through-hole solder joints, illustrating the challenges and implications of soldering in reduced gravity. SoRGE showed a significant increase in internal void defects for joints formed in low gravity compared to normal gravity. Methods for mitigating these void defects were evaluated using a modified soldering process. CRE-1 demonstrated the removal, cleaning, and replacement of electronics components by manual means on functional circuit boards. The majority of components successful passed a post-repair functional test demonstrating the feasibility of component-level repair within the confines of a spacecraft. Together, these tasks provide information to recommend material and tool improvements, training improvements, and future work to help enable electronics repairs in future space missions.

  7. Screen printed passive components for flexible power electronics.

    PubMed

    Ostfeld, Aminy E; Deckman, Igal; Gaikwad, Abhinav M; Lochner, Claire M; Arias, Ana C

    2015-01-01

    Additive and low-temperature printing processes enable the integration of diverse electronic devices, both power-supplying and power-consuming, on flexible substrates at low cost. Production of a complete electronic system from these devices, however, often requires power electronics to convert between the various operating voltages of the devices. Passive components-inductors, capacitors, and resistors-perform functions such as filtering, short-term energy storage, and voltage measurement, which are vital in power electronics and many other applications. In this paper, we present screen-printed inductors, capacitors, resistors and an RLC circuit on flexible plastic substrates, and report on the design process for minimization of inductor series resistance that enables their use in power electronics. Printed inductors and resistors are then incorporated into a step-up voltage regulator circuit. Organic light-emitting diodes and a flexible lithium ion battery are fabricated and the voltage regulator is used to power the diodes from the battery, demonstrating the potential of printed passive components to replace conventional surface-mount components in a DC-DC converter application.

  8. 77 FR 51572 - Certain Wireless Consumer Electronics Devices and Components Thereof; Institution of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-24

    ... COMMISSION Certain Wireless Consumer Electronics Devices and Components Thereof; Institution of Investigation... United States after importation of certain wireless consumer electronics devices and components thereof... importation of certain wireless consumer electronics devices and components thereof that infringe one or...

  9. Antenna with distributed strip and integrated electronic components

    DOEpatents

    Rodenbeck, Christopher T.; Payne, Jason A.; Ottesen, Cory W.

    2008-08-05

    An antenna comprises electrical conductors arranged to form a radiating element including a folded line configuration and a distributed strip configuration, where the radiating element can be in proximity to a ground conductor and/or arranged as a dipole. Embodiments of the antenna include conductor patterns formed on a printed wiring board, having a ground plane, spacedly adjacent to and coplanar with the radiating element. An antenna can comprise a distributed strip patterned on a printed wiring board, integrated with electronic components mounted on top of or below the distributed strip, and substantially within the extents of the distributed strip. Mounting of electronic components on top of or below the distributed strip has little effect on the performance of the antenna, and allows for realizing the combination of the antenna and integrated components in a compact form. An embodiment of the invention comprises an antenna including a distributed strip, integrated with a battery mounted on the distributed strip.

  10. Screen printed passive components for flexible power electronics

    NASA Astrophysics Data System (ADS)

    Ostfeld, Aminy E.; Deckman, Igal; Gaikwad, Abhinav M.; Lochner, Claire M.; Arias, Ana C.

    2015-10-01

    Additive and low-temperature printing processes enable the integration of diverse electronic devices, both power-supplying and power-consuming, on flexible substrates at low cost. Production of a complete electronic system from these devices, however, often requires power electronics to convert between the various operating voltages of the devices. Passive components—inductors, capacitors, and resistors—perform functions such as filtering, short-term energy storage, and voltage measurement, which are vital in power electronics and many other applications. In this paper, we present screen-printed inductors, capacitors, resistors and an RLC circuit on flexible plastic substrates, and report on the design process for minimization of inductor series resistance that enables their use in power electronics. Printed inductors and resistors are then incorporated into a step-up voltage regulator circuit. Organic light-emitting diodes and a flexible lithium ion battery are fabricated and the voltage regulator is used to power the diodes from the battery, demonstrating the potential of printed passive components to replace conventional surface-mount components in a DC-DC converter application.

  11. Screen printed passive components for flexible power electronics

    PubMed Central

    Ostfeld, Aminy E.; Deckman, Igal; Gaikwad, Abhinav M.; Lochner, Claire M.; Arias, Ana C.

    2015-01-01

    Additive and low-temperature printing processes enable the integration of diverse electronic devices, both power-supplying and power-consuming, on flexible substrates at low cost. Production of a complete electronic system from these devices, however, often requires power electronics to convert between the various operating voltages of the devices. Passive components—inductors, capacitors, and resistors—perform functions such as filtering, short-term energy storage, and voltage measurement, which are vital in power electronics and many other applications. In this paper, we present screen-printed inductors, capacitors, resistors and an RLC circuit on flexible plastic substrates, and report on the design process for minimization of inductor series resistance that enables their use in power electronics. Printed inductors and resistors are then incorporated into a step-up voltage regulator circuit. Organic light-emitting diodes and a flexible lithium ion battery are fabricated and the voltage regulator is used to power the diodes from the battery, demonstrating the potential of printed passive components to replace conventional surface-mount components in a DC-DC converter application. PMID:26514331

  12. The Coulomb, exchange, and correlation components of the electron-electron repulsion in harmonium atoms.

    PubMed

    Cioslowski, Jerzy

    2015-03-21

    Highly accurate Coulomb, exchange, and correlation components of the electron-electron repulsion energies of the three-electron harmonium atoms in the (2)P- and (4)P+ states are obtained for 19 values of the confinement strength ω ranging from 10(-3) to 10(3). The computed data are consistent with their ω → 0 and ω → ∞ asymptotics that are given by closed-form algebraic expressions. Robust approximants that accurately reproduce the actual values of the energy components while strictly conforming to these limits are constructed, opening an avenue to stringent tests capable of predicting the performance of electronic structure methods for systems with varying extents of the dynamical and nondynamical electron correlation. The values of the correlation components, paired with the computed 1-matrices are expected to be particularly useful in the context of benchmarking of approximate density matrix functionals.

  13. The Coulomb, exchange, and correlation components of the electron-electron repulsion in harmonium atoms

    SciTech Connect

    Cioslowski, Jerzy

    2015-03-21

    Highly accurate Coulomb, exchange, and correlation components of the electron-electron repulsion energies of the three-electron harmonium atoms in the {sup 2}P{sub −} and {sup 4}P{sub +} states are obtained for 19 values of the confinement strength ω ranging from 10{sup −3} to 10{sup 3}. The computed data are consistent with their ω → 0 and ω → ∞ asymptotics that are given by closed-form algebraic expressions. Robust approximants that accurately reproduce the actual values of the energy components while strictly conforming to these limits are constructed, opening an avenue to stringent tests capable of predicting the performance of electronic structure methods for systems with varying extents of the dynamical and nondynamical electron correlation. The values of the correlation components, paired with the computed 1-matrices are expected to be particularly useful in the context of benchmarking of approximate density matrix functionals.

  14. Airborne mineral components and trace metals in Paris region: spatial and temporal variability.

    PubMed

    Poulakis, E; Theodosi, C; Bressi, M; Sciare, J; Ghersi, V; Mihalopoulos, N

    2015-10-01

    A variety of mineral components (Al, Fe) and trace metals (V, Cr, Mn, Ni, Cu, Zn, Cd, Pb) were simultaneously measured in PM2.5 and PM10 fractions at three different locations (traffic, urban, and suburban) in the Greater Paris Area (GPA) on a daily basis throughout a year. Mineral species and trace metal levels measured in both fractions are in agreement with those reported in the literature and below the thresholds defined by the European guidelines for toxic metals (Cd, Ni, Pb). Size distribution between PM2.5 and PM10 fractions revealed that mineral components prevail in the coarse mode, while trace metals are mainly confined in the fine one. Enrichment factor analysis, statistical analysis, and seasonal variability suggest that elements such as Mn, Cr, Zn, Fe, and Cu are attributed to traffic, V and Ni to oil combustion while Cd and Pb to industrial activities with regional origin. Meteorological parameters such as rain, boundary layer height (BLH), and air mass origin were found to significantly influence element concentrations. Periods with high frequency of northern and eastern air masses (from high populated and industrialized areas) are characterized by high metal concentrations. Finally, inner city and traffic emissions were also evaluated in PM2.5 fraction. Significant contributions (>50 %) were measured in the traffic site for Mn, Fe, Cr, Zn, and Cu, confirming that vehicle emissions contribute significantly to their levels, while in the urban site, the lower contributions (18 to 33 %) for all measured metals highlight the influence of regional sources on their levels.

  15. Impact of mineral components and selected trace metals on ambient PM10 concentrations

    NASA Astrophysics Data System (ADS)

    Limbeck, Andreas; Handler, Markus; Puls, Christoph; Zbiral, Johannes; Bauer, Heidi; Puxbaum, Hans

    PM10 levels of the mineral components Si, Al, Fe, Ca, Mg and some trace metals were measured at three different sites in the urban area of Vienna (Austria). Observed trace metal concentrations varied between less than 0.1 ng m -3 (Cd) and approximately 200 ng m -3 (Zn), mineral components showed enhanced concentrations ranging from 0.01 μg m -3 (Ca) to 16.3 μg m -3 (Si). The contribution of the respective mineral oxides to PM10 mass concentrations accounted on average for 26.4 ± 16% (n = 1090) of the PM10 mass, with enhanced rates in spring and autumn (monthly averages of up to 40%) and decreased contributions in the cold season (monthly averages below 10%). The atmospheric occurrence of Al, Ti and Sr could be assigned to crustal sources, whereas for the elements Ba, Ca, Fe, Mg, Mn and V an increased contribution of non-crustal origin was observed. PM10 levels of As, Cd, Co, Cr, Cu, Ni, Pb, Sb, Sn and Zn were predominantly derived from man-made emissions. Intersite comparison indicated that urban PM10 mass concentrations and PM10 levels of As, Pb and Zn were predominantly influenced from the transport of aerosols from outside into the city, whereas for the elements Ba, Mg, Ca, Cu and Fe a distinctly increased impact of local emissions was observed. The contribution of these urban emissions to total PM10 concentrations was estimated by calculating the so-called "urban impact", which was found to be 32.7 ± 18% (n = 392) in the case of PM10 mass concentrations. The investigated elements accounted on average for 31.3 ± 19% (n = 392) of the observed PM10 mass increase. The mean values for the "urban impacts" of individual elements varied between 25.5% (As) and 77.0% (Ba).

  16. Copper-diamond composite substrates for electronic components

    SciTech Connect

    Davidson, H.L.; Colella, N.J.; Kerns, J.A.; Makowiecki, D.

    1995-01-25

    High-power density electronic components such as fast microprocessors and power semiconductors are often limited by inability to keep the device junctions below their max rated operating temperature. Present high power multichip module and single chip package designs use substrate materials such as Si nitride or copper tungsten with thermal conductivity in the range of 200 W/m{center_dot}K. We have developed a copper-diamond composite (Dymalloy) with a thermal conductivity of 420 W/m{center_dot}K, better than Cu, and an adjustable thermal expansion coefficient (TCE=5.5 ppM/C at 25 C), compatible with Si and GaAs. Because of the matched TCE, it is possible to use low thermal resistance hard die attach methods. The mechanical properties of the composite also make it attractive as an electronic component substrate material.

  17. A transmission electron microscopy study of mineralization in age-induced transparent dentin.

    PubMed

    Porter, Alexandra E; Nalla, Ravi K; Minor, Andrew; Jinschek, Joerg R; Kisielowski, Christian; Radmilovic, Velimir; Kinney, John H; Tomsia, Antoni P; Ritchie, R O

    2005-12-01

    It is known that fractures are more likely to occur in altered teeth, particularly following restoration or endodontic repair; consequently, it is important to understand the structure of altered forms of dentin, the most abundant tissue in the human tooth, in order to better define the increased propensity for such fractures. Transparent (or sclerotic) dentin, wherein the dentinal tubules become occluded with mineral as a natural progressive consequence of aging, is one such altered form. In the present study, high-resolution transmission electron microscopy is used to investigate the effect of aging on the mineral phase of dentin. Such studies revealed that the intertubular mineral crystallites were smaller in transparent dentin, and that the intratubular mineral (larger crystals deposited within the tubules) was chemically similar to the surrounding intertubular mineral. Exit-wave reconstructed lattice-plane images suggested that the intratubular mineral had nanometer-size grains. These observations support a "dissolution and reprecipitation" mechanism for the formation of transparent dentin.

  18. Component technologies for a recirculating linac free-electron laser

    NASA Astrophysics Data System (ADS)

    Litvinenko, Vladimir N.; Madey, John M. J.; Vinokurov, Nikolai A.

    1994-05-01

    The key component technologies required for a high average power free-electron laser (FEL) are described. Some basic aspects of approaches for high average power (scalable to megawatt level) accelerators and FELs are presented. A short description of the Novosibirsk 100 kW average power near infrared (IR) FEL driven by a race-track microtron-recuperator is given. The current status and plans for this facility are provided by Institute of Nuclear Physics (Novosibirsk).

  19. Electronic Components and Circuits for Extreme Temperature Environments

    NASA Technical Reports Server (NTRS)

    Patterson, Richard L.; Hammoud, Ahmad; Dickman, John E.; Gerber, Scott

    2003-01-01

    Planetary exploration missions and deep space probes require electrical power management and control systems that are capable of efficient and reliable operation in very low temperature environments. Presently, spacecraft operating in the cold environment of deep space carry a large number of radioisotope heating units in order to maintain the surrounding temperature of the on-board electronics at approximately 20 C. Electronics capable of operation at cryogenic temperatures will not only tolerate the hostile environment of deep space but also reduce system size and weight by eliminating or reducing the radioisotope heating units and their associate structures; thereby reducing system development as well as launch costs. In addition, power electronic circuits designed for operation at low temperatures are expected to result in more efficient systems than those at room temperature. This improvement results from better behavior and tolerance in the electrical and thermal properties of semiconductor and dielectric materials at low temperatures. The Low Temperature Electronics Program at the NASA Glenn Research Center focuses on research and development of electrical components, circuits, and systems suitable for applications in the aerospace environment and deep space exploration missions. Research is being conducted on devices and systems for reliable use down to cryogenic temperatures. Some of the commercial-off-the-shelf as well as developed components that are being characterized include switching devices, resistors, magnetics, and capacitors. Semiconductor devices and integrated circuits including digital-to-analog and analog-to-digital converters, DC/DC converters, operational amplifiers, and oscillators are also being investigated for potential use in low temperature applications. An overview of the NASA Glenn Research Center Low Temperature Electronic Program will be presented in this paper. A description of the low temperature test facilities along with

  20. Electronic Components and Systems for Cryogenic Space Applications

    NASA Technical Reports Server (NTRS)

    Patterson, R. L.; Hammoud, A.; Dickman, J. E.; Gerber, S.; Elbuluk, M. E.; Overton, E.

    2001-01-01

    Electronic components and systems capable of operation at cryogenic temperatures are anticipated in many future NASA space missions such as deep space probes and planetary surface exploration. For example, an unheated interplanetary probe launched to explore the rings of Saturn would reach an average temperature near Saturn of about - 183 C. In addition to surviving the deep space harsh environment, electronics capable of low temperature operation would contribute to improving circuit performance, increasing system efficiency, and reducing payload development and launch costs. Terrestrial applications where components and systems must operate in low temperature environments include cryogenic instrumentation, superconducting magnetic energy storage, magnetic levitation transportation system, and arctic exploration. An on-going research and development program at the NASA Glenn Research Center focuses on the development of reliable electronic devices and efficient power systems capable of surviving in low temperature environments. An overview of the program will be presented in this paper. A description of the low temperature test facilities along with selected data obtained from in-house component testing will also be discussed. Ongoing research activities that are being performed in collaboration with various organizations will also be presented.

  1. Transmission electron microscopic examination of phosphoric acid fuel cell components

    NASA Technical Reports Server (NTRS)

    Pebler, A.

    1986-01-01

    Transmission electron microscopy (TEM) was used to physically characterize tested and untested phosphoric acid fuel cell (PAFC) components. Those examined included carbon-supported platinum catalysts, carbon backing paper, and Teflon-bonded catalyst layers at various stages of fabrication and after testing in pressurized PAFC's. Applicability of electron diffraction and electron energy loss spectroscopy for identifying the various phases was explored. The discussion focuses on the morphology and size distribution of platinum, the morphology and structural aspects of Teflon in catalyst layers, and the structural evidence of carbon corrosion. Reference is made to other physical characterization techniques where appropriate. A qualitative model of the catalyst layer that emerged from the TEM studies is presented.

  2. Electron transfer from humic substances to biogenic and abiogenic Fe(III) oxyhydroxide minerals.

    PubMed

    Piepenbrock, Annette; Schröder, Christian; Kappler, Andreas

    2014-01-01

    Microbial humic substance (HS) reduction and subsequent abiotic electron transfer from reduced HS to poorly soluble Fe(III) (oxyhydr)oxides, a process named electron shuttling, significantly increases microbial Fe(III) mineral reduction rates. However, the importance of electron shuttling in nature and notably the electron transfer from HS to biogenic Fe(III) (oxyhydr)oxides have thus far not been determined. In this study, we have quantified the rate and extent of electron transfer from reduced and nonreduced Pahokee Peat humic acids (PPHA) and fresh soil organic matter (SOM) extracts to both synthetic and environmentally relevant biogenic Fe(III) (oxyhydr)oxides. We found that biogenic Fe(III) minerals were reduced faster and to an equal or higher degree than their abiogenic counterparts. Differences were attributed to differences in crystallinity and the association of bacterial biomass with biogenic minerals. Compared to purified PPHA, SOM extract transferred fewer electrons per milligram of carbon and electron transfer was observed only to poorly crystalline ferrihydrite but not to more crystalline goethite. This indicates a difference in redox potential distribution of the redox-active functional groups in extracted SOM relative to the purified PPHA. Our results suggest that HS electron shuttling can also contribute to iron redox processes in environments where biogenic Fe(III) minerals are present.

  3. Component Repair Experiment-1: An Experiment Evaluating Electronic Component-Level Repair During Spaceflight

    NASA Technical Reports Server (NTRS)

    Easton, John W.; Struk, Peter M.

    2012-01-01

    The Component Repair Experiment-1 (CRE-1) examines the capability for astronauts to perform electronics repair tasks in space. The goal is to determine the current capabilities and limits for the crew, and to make recommendations to improve and expand the range of work that astronauts may perform. CRE-1 provided two-layer, functional circuit boards and replacement components, a small tool kit, written and video training materials, and 1 hr of hands on training for the crew slated to perform the experiment approximately 7 months prior to the mission. Astronauts Michael Fincke and Sandra Magnus performed the work aboard the International Space Station (ISS) in February and March 2009. The astronauts were able to remove and replace components successfully, demonstrating the feasibility of performing component-level electronics repairs within a spacecraft. Several unsuccessful tasks demonstrated areas in need of improvement. These include improved and longer training prior to a mission, an improved soldering iron with a higher operating temperature and steady power source, video training and practice boards for refresher work or practice before a repair, and improved and varied hand tools and containment system.

  4. Electronic Components for use in Extreme Temperature Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Patterson, Richard L.; Hammoud, Ahmad; Elbuluk, Malik

    2008-01-01

    Electrical power management and control systems designed for use in planetary exploration missions and deep space probes require electronics that are capable of efficient and reliable operation under extreme temperature conditions. Space-based infra-red satellites, all-electric ships, jet engines, electromagnetic launchers, magnetic levitation transport systems, and power facilities are also typical examples where the electronics are expected to be exposed to harsh temperatures and to operate under severe thermal swings. Most commercial-off-the-shelf (COTS) devices are not designed to function under such extreme conditions and, therefore, new parts must be developed or the conventional devices need to be modified. For example, spacecraft operating in the cold environment of deep space carry a large number of radioisotope heating units in order to maintain the surrounding temperature of the on-board electronics at approximately 20 C. At the other end, built-in radiators and coolers render the operation of electronics possible under hot conditions. These thermal measures lead to design complexity, affect development costs, and increase size and weight. Electronics capable of operation at extreme temperatures, thus, will not only tolerate the hostile operational environment, but also make the overall system efficient, more reliable, and less expensive. The Extreme Temperature Electronics Program at the NASA Glenn Research Center focuses on research and development of electronics suitable for applications in the aerospace environment and deep space exploration missions. Research is being conducted on devices, including COTS parts, for potential use under extreme temperatures. These components include semiconductor switching devices, passive devices, DC/DC converters, operational amplifiers, and oscillators. An overview of the program will be presented along with some experimental findings.

  5. 77 FR 34063 - Certain Electronic Devices, Including Mobile Phones and Tablet Computers, and Components Thereof...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-08

    ... COMMISSION Certain Electronic Devices, Including Mobile Phones and Tablet Computers, and Components Thereof... devices, including mobile phones and tablet computers, and components thereof by reason of infringement of... certain electronics devices, including mobile phones and tablet computers, and components thereof...

  6. 77 FR 44671 - Certain Wireless Consumer Electronics Devices and Components Thereof; Notice of Receipt of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-30

    ... COMMISSION Certain Wireless Consumer Electronics Devices and Components Thereof; Notice of Receipt of... received a complaint entitled Certain Wireless Consumer Electronics Devices and Components Thereof, DN 2904... within the United States after importation of certain wireless consumer electronics devices...

  7. 77 FR 27078 - Certain Electronic Devices, Including Mobile Phones and Tablet Computers, and Components Thereof...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-08

    ... COMMISSION Certain Electronic Devices, Including Mobile Phones and Tablet Computers, and Components Thereof... Trade Commission has received a complaint entitled Certain Electronic Devices, Including Mobile Phones... electronic devices, including mobile phones and tablet computers, and components thereof. The complaint...

  8. 76 FR 22918 - In the Matter of Certain Handheld Electronic Computing Devices, Related Software, and Components...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-25

    ... COMMISSION In the Matter of Certain Handheld Electronic Computing Devices, Related Software, and Components... States after importation of certain handheld electronic computing devices, related software, and... importation of certain handheld electronic computing devices, related software, and components thereof...

  9. Analysis of minerals containing dissolved traces of the fluid phase components water and carbon dioxide

    NASA Technical Reports Server (NTRS)

    Freund, Friedemann

    1991-01-01

    Substantial progress has been made towards a better understanding of the dissolution of common gas/fluid phase components, notably H2O and CO2, in minerals. It has been shown that the dissolution mechanisms are significantly more complex than currently believed. By judiciously combining various solid state analytical techniques, convincing evidence was obtained that traces of dissolved gas/fluid phase components undergo, at least in part, a redox conversion by which they split into reduced H2 and and reduced C on one hand and oxidized oxygen, O(-), on the other. Analysis for 2 and C as well as for any organic molecules which may form during the process of co-segregation are still impeded by the omnipresent danger of extraneous contamination. However, the presence of O(-), an unusual oxidized form of oxygen, has been proven beyond a reasonable doubt. The presence of O(-) testifies to the fact that a redox reaction must have taken place in the solid state involving the dissolved traces of gas/fluid phase components. Detailed information on the techniques used and the results obtained are given.

  10. Mass specific optical absorption coefficients of mineral dust components measured by a multi wavelength photoacoustic spectrometer

    NASA Astrophysics Data System (ADS)

    Utry, N.; Ajtai, T.; Pintér, M.; Tombácz, E.; Illés, E.; Bozóki, Z.; Szabó, G.

    2014-09-01

    Mass specific optical absorption coefficients of various mineral dust components including silicate clays (illite, kaolin and bentonite), oxides (quartz, hematite and rutile), and carbonate (limestone) were determined at wavelengths of 1064, 532, 355 and 266 nm. These values were calculated from aerosol optical absorption coefficients measured by a multi-wavelength photoacoustic (PA) instrument, the mass concentration and the number size distribution of the generated aerosol samples as well as the size transfer functions of the measuring instruments. These results are expected to have considerable importance in global radiative forcing calculations. They can also serve as reference for validating calculated wavelength dependent imaginary parts (κ) of complex refractive indices which up to now have been typically deduced from bulk phase measurements by using indirect measurement methods. Accordingly, the presented comparison of the measured and calculated aerosol optical absorption spectra revealed the strong need for standardized sample preparation and measurement methodology in case of bulk phase measurements.

  11. The ‘porin–cytochrome’ model for microbe-to-mineral electron transfer

    SciTech Connect

    Richardson, David J.; Butt, Julea N.; Fredrickson, Jim K.; Zachara, John M.; Shi, Liang; Edwards, Marcus J.; White, Gaye F.; Baiden, Nanakow; Gates, Andrew J.; Marritt, Sophie; Clarke, Thomas A.

    2012-05-30

    Many species of bacteria can couple anaerobic growth to the respiratory reduction of insoluble minerals containing Fe(III) or Mn(III/IV). It has been suggested that in Shewanella species electrons cross the outer membrane to extracellular substrates via 'porin-cytochrome' electron transport modules. The molecular structure of an outer-membrane extracellular-facing deca-haem terminus for such a module has recently been resolved. It is debated how, once outside the cells, electrons are transferred from outer-membrane cytochromes to insoluble electron sinks. This may occur directly or by assemblies of cytochromes, perhaps functioning as 'nanowires', or via electron shuttles. Here we review recent work in this field and explore whether it allows for unification of the electron transport mechanisms supporting extracellular mineral respiration in Shewanella that may extend into other genera of Gram-negative bacteria.

  12. Secondary Mineralization of Components in CV3 Chondrites: Nebular and Asteroidal Models

    NASA Astrophysics Data System (ADS)

    Scott, E. R. D.; Krot, A. N.; Zolensky, M. E.

    1995-09-01

    Our review of mineralogical variations among CV3 chondrites suggests that all components, chondrules, matrices, and CAIs, were affected by various degrees of secondary mineralization. Chondrules and CAIs are rimmed with fayalitic olivine [1, 2]; metal in all components is oxidized and sulfidized to magnetite, Ni-rich metal and sulfides [3]; silicates in all components are aqueously altered to phyllosilicates [4]; and nepheline, sodalite, wollastonite, and hedenbergite replace primary minerals in CAIs [5]. In those CV3s with altered CAIs, nepheline etc. are also present in chondrule mesostases [6] and in matrices [7]. Correlated occurrences of secondary minerals indicate that they have related origins. CV3 chondrites can be divided into three kinds according to their secondary features. Reduced CV3s (e.g., Efremovka) lack magnetite [8] and show minimal secondary features. Oxidized CV3s [8] generally show all features: those like Mokoia contain minor fayalitic rims, nepheline, etc, whereas those like Allende lack phyllosilicates but contain well developed fayalite rims and abundant nepheline, etc. Allende-like CV3 chondrites also contain abundant plate-like matrix olivine (Fa(sub)45-55). Similarities in chemistry and O isotopic composition and petrographic observations suggest that fayalitic rims and plate-like matrix olivine have related origins [1, 9]. The presence of secondary minerals in all components implies that alteration postdated component formation. The absence of secondary minerals in reduced CV3s indicates that CV3 oxidized formed from CV3 reduced-like material. Oxidized and reduced materials coexist in some breccias indicating a common parent asteroid. Nebular origins are widely accepted for most secondary features. To form fayalitic rims and matrix , Palme and colleagues [10, 11] suggest that chondritic components were briefly exposed to a hot (>1500 K), highly oxidizing nebula with H2O/H2 to about 1. Such an environment could have resulted from

  13. Analysis of electronic component failures using high-density radiography

    SciTech Connect

    Tuohig, W.D.; Potter, T.J.

    1991-11-01

    The exceptional resolution and nondestructive nature of microfocus radiography has proven to be extremely useful in the diagnosis of electronic component failures, particularly when the components are contained in sealed or encapsulated assemblies. An epoxy-encapsulated NTC thermistor and an epitaxial silicon P-N junction photodetector are examples of discrete devices in which the cause of failure was correctly hypothesized directly from a radiographic image. Subsequent destructive physical examinations confirmed the initial hypothesis and established the underlying cause in each case. The problem in a vacuum switch tube which failed to function was apparent in the radiographic image, but the underlying cause was not clear. However, radiography also showed that the position of a flat cable in the assembly could contribute to failure, an observation which resulted in a change in manufacturing procedure. In each of these instances, microradiography played a key role in decisions concerning the root cause of failure, product viability, and corrective action. 15 refs., 10 figs.

  14. A new active solder for joining electronic components

    SciTech Connect

    SMITH,RONALD W.; VIANCO,PAUL T.; HERNANDEZ,CYNTHIA L.; LUGSCHEIDER,E.; RASS,I.; HILLEN,F.

    2000-05-11

    Electronic components and micro-sensors utilize ceramic substrates, copper and aluminum interconnect and silicon. The joining of these combinations require pre-metallization such that solders with fluxes can wet such combinations of metals and ceramics. The paper will present a new solder alloy that can bond metals, ceramics and composites. The alloy directly wets and bonds in air without the use flux or premetallized layers. The paper will present typical processing steps and joint microstructures in copper, aluminum, aluminum oxide, aluminum nitride, and silicon joints.

  15. Solder Reflow Failures in Electronic Components During Manual Soldering

    NASA Technical Reports Server (NTRS)

    Teverovsky, Alexander; Greenwell, Chris; Felt, Frederick

    2008-01-01

    This viewgraph presentation reviews the solder reflow failures in electronic components that occur during manual soldering. It discusses the specifics of manual-soldering-induced failures in plastic devices with internal solder joints. The failure analysis turned up that molten solder had squeezed up to the die surface along the die molding compound interface, and the dice were not protected with glassivation allowing solder to short gate and source to the drain contact. The failure analysis concluded that the parts failed due to overheating during manual soldering.

  16. Dymalloy: A composite substrate for high power density electronic components

    SciTech Connect

    Kerns, J.A.; Colella, N.J.; Makowiecki, D.; Davidson, H.L.

    1995-06-29

    High power density electronic components such as fast microprocessors and power semiconductors must operate below the maximum rated device junction temperature to ensure reliability. function temperatures are determined by the amount of heat generated and the thermal resistance from junction to the ambient thermal environment. Two of the Largest contributions to this thermal resistance are the die attach interface and the package base. A decrease in these resistances can allow increased component packing density in MCMs, reduction of heat sink volume in tightly packed systems, enable the use of higher performance circuit components, and improve reliability. The substrate for high power density devices is the primary thermal link between the junctions and the heat sink. Present high power multichip modules and single chip packages use substrate materials such as silicon nitride or copper tungsten that have thermal conductivity in the range of 200 W/mK. We have developed Dymalloy, a copper-diamond composite, that has a thermal conductivity of 420 W/mK and an adjustable coefficient of thermal expansion, nominally 5.5 ppm/C at 25 C, compatible with silicon and gallium arsenide. Because of the matched coefficient of thermal expansion it is possible to use low thermal resistance hard die attach methods. Dymalloy is a composite material made using micron size Type I diamond powder that has a published thermal conductivity of 600 to 1000 W/mK in a metal matrix that has a thermal conductivity of 350 W/mK. The region of chemical bonding between the matrix material and diamond is limited to approximately 1000 A to maintain a high effective thermal conductivity for the composite. The material may be fabricated in near net shapes. Besides having exceptional thermal properties, the mechanical properties of this material also make it an attractive candidate as an electronic component substrate material.

  17. Optical-electronic system for express analysis of mineral raw materials dressability by color sorting method

    NASA Astrophysics Data System (ADS)

    Alekhin, Artem A.; Gorbunova, Elena V.; Chertov, Aleksandr N.; Petuhova, Darya B.

    2013-04-01

    Due to the depletion of solid minerals ore reserves and the involvement in the production of the poor and refractory ores a process of continuous appreciation of minerals is going. In present time at the market of enrichment equipment are well represented optical sorters of various firms. All these sorters are essentially different from each other by parameters of productivity, classes of particles sizes for processed raw, nuances of decision algorithm, as well as by color model (RGB, YUV, HSB, etc.) chosen to describe the color of separating mineral samples. At the same time there is no dressability estimation method for mineral raw materials without direct semi-industrial test on the existing type of optical sorter, as well as there is no equipment realizing mentioned dressability estimation method. It should also be note the lack of criteria for choosing of one or another manufacturer (or type) of optical sorter. A direct consequence of this situation is the "opacity" of the color sorting method and the rejection of its potential customers. The proposed solution of mentioned problems is to develop the dressability estimation method, and to create an optical-electronic system for express analysis of mineral raw materials dressability by color sorting method. This paper has the description of structure organization and operating principles of experimental model optical-electronic system for express analysis of mineral raw material. Also in this work are represented comparison results of the proposed optical-electronic system and the real color sorter.

  18. Microbial mineralization of VC and DCE under different terminal electron accepting conditions

    USGS Publications Warehouse

    Bradley, P.M.; Chapelle, F.H.

    1998-01-01

    Production of 14CO2 from [1,2-14C] dichloroethene (DCE) or [1,2-14C] vinyl chloride (VC) was quantified in aquifer and stream-bed sediment microcosms to evaluate the potential for microbial mineralization as a pathway for DCE and VC biodegradation under aerobic, Fe(III)-reducing, SO4-reducing, and methanogenic conditions. Mineralization of [1,2-14C] DCE and [1,2-14C] VC to 14CO2 decreased under increasingly reducing conditions, but significant mineralization was observed for both sediments even under anaerobic conditions. VC mineralization decreased in the order of aerobic > Fe(III)-reducing > SO4-reducing > methanogenic conditions. For both sediments, VC mineralization was greater than DCE mineralization under all electron-accepting conditions examined. For both sediments, DCE mineralization was at least two times greater under aerobic conditions than under anaerobic conditions. Although significant microbial mineralization of DCE was observed under anaerobic conditions, recovery of 14CO2 did not differ substantially between anaerobic treatments.

  19. Nanostructured component fabrication by electron beam-physical vapor deposition

    NASA Astrophysics Data System (ADS)

    Singh, Jogender; Wolfe, Douglas E.

    2005-08-01

    Fabrication of cost-effective, nano-grained net-shaped components has brought considerable interest to Department of Defense, National Aeronautics and Space Administration, and Department of Energy. The objective of this paper is to demonstrate the versatility of electron beam-physical vapor deposition (EB-PVD) technology in engineering new nanostructured materials with controlled microstructure and microchemistry in the form of coatings and net-shaped components for many applications including the space, turbine, optical, biomedical, and auto industries. Coatings are often applied on components to extent their performance and life under severe environmental conditions including thermal, corrosion, wear, and oxidation. Performance and properties of the coatings depend upon their composition, microstructure, and deposition condition. Simultaneous co-evaporation of multiple ingots of different compositions in the high energy EB-PVD chamber has brought considerable interest in the architecture of functional graded coatings, nano-laminated coatings, and design of new structural materials that could not be produced economically by conventional methods. In addition, high evaporation and condensate rates allowed fabricating precision net-shaped components with nanograined microstructure for various applications. Using EB-PVD, nano-grained rhenium (Re) coatings and net-shaped components with tailored microstructure and properties were fabricated in the form of tubes, plates, and Re-coated spherical graphite cores. This paper will also present the results of various metallic and ceramic coatings including chromium, titanium carbide (TiC), titanium diboride (TiB2), hafnium nitride (HfN), titanium-boron-carbonitride (TiBCN), and partially yttria stabilized zirconia (YSZ) TBC coatings deposited by EB-PVD for various applications.

  20. Component-Level Electronic-Assembly Repair (CLEAR) Operational Concept

    NASA Technical Reports Server (NTRS)

    Oeftering, Richard C.; Bradish, Martin A.; Juergens, Jeffrey R.; Lewis, Michael J.; Vrnak, Daniel R.

    2011-01-01

    This Component-Level Electronic-Assembly Repair (CLEAR) Operational Concept document was developed as a first step in developing the Component-Level Electronic-Assembly Repair (CLEAR) System Architecture (NASA/TM-2011-216956). The CLEAR operational concept defines how the system will be used by the Constellation Program and what needs it meets. The document creates scenarios for major elements of the CLEAR architecture. These scenarios are generic enough to apply to near-Earth, Moon, and Mars missions. The CLEAR operational concept involves basic assumptions about the overall program architecture and interactions with the CLEAR system architecture. The assumptions include spacecraft and operational constraints for near-Earth orbit, Moon, and Mars missions. This document addresses an incremental development strategy where capabilities evolve over time, but it is structured to prevent obsolescence. The approach minimizes flight hardware by exploiting Internet-like telecommunications that enables CLEAR capabilities to remain on Earth and to be uplinked as needed. To minimize crew time and operational cost, CLEAR exploits offline development and validation to support online teleoperations. Operational concept scenarios are developed for diagnostics, repair, and functional test operations. Many of the supporting functions defined in these operational scenarios are further defined as technologies in NASA/TM-2011-216956.

  1. Polarizing and Light Microscopic Analysis of Mineralized Components and Stromal Elements in Fibrous Ossifying Lesions

    PubMed Central

    Kulkarni, Rasika R; Sarvade, Sriranjani D; Boaz, Karen; KP, Nandita; Lewis, Amitha J

    2014-01-01

    Introduction: Fibro-osseous lesions, along with few reactive lesions of the jaws exhibit an overlapping histo-morphologic spectrum with respect to the nature of calcifications and stromal components. This causes difficulty in assessing the origin, pathogenesis and diagnosis of these lesions. Aim: The present study analyses the mineralized components, cellularity, stromal density and stromal composition (nature of collagen, presence of elastic and oxytalan fibres) in cases of ossifying fibroma (OF), fibrous dysplasia (FD) and peripheral ossifying fibroma (POF). Materials and Methods: The study included a histochemical evaluation of six cases each of FD, OF and POF. Five consecutive sections of each case were stained with hematoxylin and eosin, picrosirius red (to assess maturation of fibres in polarizing light), van Gieson (for area fraction and collagen density) and aldehyde fuchsin (for elastic and oxytalan fibres) respectively. Results: Significantly higher amounts of mature bone were seen in FD while cementicles having microlamellar pattern were predominant in OF and POF (p < 0.001). Area fraction, collagen density and immature stromal fibre content was higher in POF followed by FD and OF (p= 0.039). Oxytalan and elastic fibres were absent in FD. Conclusion: Higher cellularity of the stroma in OF was indicative of its neoplastic behaviour. Higher composition of oxytalan and elastic fibres in OF and POF supports their periodontal ligament origin. FD was distinct with more mature fibres in a lamellated bone and absence of oxytalan fibres. PMID:25121063

  2. Electron Transport at the Microbe–Mineral Interface: A Synthesis of Current Research Challenges

    SciTech Connect

    Richardson, David; Fredrickson, Jim K.; Zachara, John M.

    2012-12-01

    Many bacterial and archaeal species can couple growth to the respiratory reduction or oxidation of insoluble mineral oxides of transition metals. These solid substrates are abundant electron sinks and sources for life on Earth, but, since they are insoluble in water, they cannot enter the bacterial cells. So, to exploit these electron sinks and sources, specific respiratory electron-transfer mechanisms must overcome the physical limitations associated with electron transfer between a microbe and extracellular metal oxides. Recent microbiological, geochemical, biochemical, spectroscopic and structural work is beginning to shed light on the molecular mechanism and impacts of electron transfer at themicrobe–mineral interface from a nanometre to kilometre scale. The research field is attracting attention in applied quarters from those with interests in nanowires, microbial fuel cells, bioremediation and microbial cell factories.

  3. Electron transport at the microbe-mineral interface: a synthesis of current research challenges.

    PubMed

    Richardson, David J; Fredrickson, James K; Zachara, John M

    2012-12-01

    Many bacterial and archaeal species can couple growth to the respiratory reduction or oxidation of insoluble mineral oxides of transition metals. These solid substrates are abundant electron sinks and sources for life on Earth, but, since they are insoluble in water, they cannot enter the bacterial cells. So, to exploit these electron sinks and sources, specific respiratory electron-transfer mechanisms must overcome the physical limitations associated with electron transfer between a microbe and extracellular metal oxides. Recent microbiological, geochemical, biochemical, spectroscopic and structural work is beginning to shed light on the molecular mechanism and impacts of electron transfer at the microbe-mineral interface from a nanometre to kilometre scale. The research field is attracting attention in applied quarters from those with interests in nanowires, microbial fuel cells, bioremediation and microbial cell factories. PMID:23176448

  4. High energy electron beam joining of ceramic components

    SciTech Connect

    Turman, B.N.; Glass, S.J.; Halbleib, J.A.

    1997-07-01

    High strength, hermetic braze joints between ceramic components have been produced using high energy electron beams. With a penetration depth into a typical ceramic of {approximately}1 cm for a 10 MeV electron beam, this method provides the capability for rapid, transient brazing operations where temperature control of critical components is essential. The method deposits energy directly into a buried joint, allowing otherwise inaccessible interfaces to be brazed. Because of transient heating, higher thermal conductivity, lower heat capacity, and lower melting temperature of braze metals relative to the ceramic materials, a pulsed high power beam can melt a braze metal without producing excessive ceramic temperatures. We have demonstrated the feasibility of this process related to ceramic coupons as well as ceramic and glass tubes. The transient thermal response was predicted, using as input the energy absorption predicted from the coupled electron-photon transport analysis. The joining experiments were conducted with an RF Linac accelerator at 10-13 MV. The repetition rate of the pulsed beam was varied between 8 and 120 Hz, the average beam current was varied between 8 and 120 microamps, and the power was varied up to 1.5 kW. These beam parameters gave a beam power density between 0.2 to 2 kW/cm{sup 2}. The duration of the joining runs varied from 5 to 600 sec. Joining experiments have provided high strength between alumina - alumina and alumina - cermet joints in cylindrical geometry. These joints provided good hermetic seals. A series of tests was conducted to determine the minimum beam power and exposure time for producing, a hermetic seal.

  5. Nanoanalytical Electron Microscopy Reveals a Sequential Mineralization Process Involving Carbonate-Containing Amorphous Precursors.

    PubMed

    Nitiputri, Kharissa; Ramasse, Quentin M; Autefage, Hélène; McGilvery, Catriona M; Boonrungsiman, Suwimon; Evans, Nicholas D; Stevens, Molly M; Porter, Alexandra E

    2016-07-26

    A direct observation and an in-depth characterization of the steps by which bone mineral nucleates and grows in the extracellular matrix during the earliest stages of maturation, using relevant biomineralization models as they grow into mature bone mineral, is an important research goal. To better understand the process of bone mineralization in the extracellular matrix, we used nanoanalytical electron microscopy techniques to examine an in vitro model of bone formation. This study demonstrates the presence of three dominant CaP structures in the mineralizing osteoblast cultures: <80 nm dense granules with a low calcium to phosphate ratio (Ca/P) and crystalline domains; calcium phosphate needles emanating from a focus: "needle-like globules" (100-300 nm in diameter) and mature mineral, both with statistically higher Ca/P compared to that of the dense granules. Many of the submicron granules and globules were interspersed around fibrillar structures containing nitrogen, which are most likely the signature of the organic phase. With high spatial resolution electron energy loss spectroscopy (EELS) mapping, spatially resolved maps were acquired showing the distribution of carbonate within each mineral structure. The carbonate was located in the middle of the granules, which suggested the nucleation of the younger mineral starts with a carbonate-containing precursor and that this precursor may act as seed for growth into larger, submicron-sized, needle-like globules of hydroxyapatite with a different stoichiometry. Application of analytical electron microscopy has important implications in deciphering both how normal bone forms and in understanding pathological mineralization. PMID:27383526

  6. Component-Level Electronic-Assembly Repair (CLEAR) System Architecture

    NASA Technical Reports Server (NTRS)

    Oeftering, Richard C.; Bradish, Martin A.; Juergens, Jeffrey R.; Lewis, Michael J.; Vrnak, Daniel R.

    2011-01-01

    This document captures the system architecture for a Component-Level Electronic-Assembly Repair (CLEAR) capability needed for electronics maintenance and repair of the Constellation Program (CxP). CLEAR is intended to improve flight system supportability and reduce the mass of spares required to maintain the electronics of human rated spacecraft on long duration missions. By necessity it allows the crew to make repairs that would otherwise be performed by Earth based repair depots. Because of practical knowledge and skill limitations of small spaceflight crews they must be augmented by Earth based support crews and automated repair equipment. This system architecture covers the complete system from ground-user to flight hardware and flight crew and defines an Earth segment and a Space segment. The Earth Segment involves database management, operational planning, and remote equipment programming and validation processes. The Space Segment involves the automated diagnostic, test and repair equipment required for a complete repair process. This document defines three major subsystems including, tele-operations that links the flight hardware to ground support, highly reconfigurable diagnostics and test instruments, and a CLEAR Repair Apparatus that automates the physical repair process.

  7. [Spatial heterogeneity of surface soil mineral components in a small catchment in Karst peak-cluster depression area, South China].

    PubMed

    Gao, Peng; Fu, Tong-Gang; Wang, Ke-Lin; Chen, Hong-Song; Zeng, Fu-Ping

    2013-11-01

    A total of 163 soil samples (0-20 cm layer) were collected from the grid sampling plots (80 m x 80 m) in Huanjiang Observation and Research Station of Karst Ecosystem in a small catchment in Karst cluster-peak depression area, South China. By using classical statistics and geostatistics, the spatial heterogeneity of mineral components (SiO2, Fe2O3, CaO, MgO, Al2O3, MnO, and TiO2) in the soils were studied. The contents of the seven soil mineral components in the study area differed greatly, being in the order of SiO2 > Al2O3 > CaO > MgO > Fe2O3 > TiO2 > MnO, and the variance coefficients also varied obviously, in the order of CaO > MgO > Fe2O3 > TiO2 > SiO2 > Al2O3 > MnO. The seven mineral components accounted for 69.4% of the total soil mass. The spatial patterns and the fittest models of the seven soil mineral components differed from each other. All the seven soil mineral components had a strong spatial autocorrelation, with shorter variation ranges and stronger spatial dependence. The Kriging contour maps indicated that the distribution patterns of soil SiO2, Fe2O3, Al2O3, MnO, and TiO2 were similar, being higher in south and east, lower in north and west, higher in depression, and lower in slope, while the distribution patterns of soil CaO and MgO were in adverse. Natural conditions (vegetation, bare rock rate, slope degree, and slope aspect, etc. ) and human disturbance were the most important factors affecting the spatial patterns of the soil mineral components. PMID:24564147

  8. [Spatial heterogeneity of surface soil mineral components in a small catchment in Karst peak-cluster depression area, South China].

    PubMed

    Gao, Peng; Fu, Tong-Gang; Wang, Ke-Lin; Chen, Hong-Song; Zeng, Fu-Ping

    2013-11-01

    A total of 163 soil samples (0-20 cm layer) were collected from the grid sampling plots (80 m x 80 m) in Huanjiang Observation and Research Station of Karst Ecosystem in a small catchment in Karst cluster-peak depression area, South China. By using classical statistics and geostatistics, the spatial heterogeneity of mineral components (SiO2, Fe2O3, CaO, MgO, Al2O3, MnO, and TiO2) in the soils were studied. The contents of the seven soil mineral components in the study area differed greatly, being in the order of SiO2 > Al2O3 > CaO > MgO > Fe2O3 > TiO2 > MnO, and the variance coefficients also varied obviously, in the order of CaO > MgO > Fe2O3 > TiO2 > SiO2 > Al2O3 > MnO. The seven mineral components accounted for 69.4% of the total soil mass. The spatial patterns and the fittest models of the seven soil mineral components differed from each other. All the seven soil mineral components had a strong spatial autocorrelation, with shorter variation ranges and stronger spatial dependence. The Kriging contour maps indicated that the distribution patterns of soil SiO2, Fe2O3, Al2O3, MnO, and TiO2 were similar, being higher in south and east, lower in north and west, higher in depression, and lower in slope, while the distribution patterns of soil CaO and MgO were in adverse. Natural conditions (vegetation, bare rock rate, slope degree, and slope aspect, etc. ) and human disturbance were the most important factors affecting the spatial patterns of the soil mineral components.

  9. Two-component magnetic structure of iron oxide nanoparticles mineralized in Listeria innocua protein cages

    NASA Astrophysics Data System (ADS)

    Usselman, Robert J.; Klem, Michael T.; Russek, Stephen E.; Young, Mark; Douglas, Trevor; Goldfarb, Ron B.

    2010-06-01

    Magnetometry was used to determine the magnetic properties of maghemite (γ-Fe2O3) nanoparticles formed within Listeria innocua protein cage. The electron magnetic resonance spectrum shows the presence of at least two magnetization components. The magnetization curves are explained by a sum of two Langevin functions in which each filled protein cage contains both a large magnetic iron oxide core plus an amorphous surface consisting of small noncoupled iron oxide spin clusters. This model qualitatively explains the observed decrease in the temperature dependent saturation moment and removes an unrealistic temperature dependent increase in the particle moment often observed in nanoparticle magnetization measurements.

  10. Arbitrary amplitude fast electron-acoustic solitons in three-electron component space plasmas

    NASA Astrophysics Data System (ADS)

    Mbuli, L. N.; Maharaj, S. K.; Bharuthram, R.; Singh, S. V.; Lakhina, G. S.

    2016-06-01

    We examine the characteristics of fast electron-acoustic solitons in a four-component unmagnetised plasma model consisting of cool, warm, and hot electrons, and cool ions. We retain the inertia and pressure for all the plasma species by assuming adiabatic fluid behaviour for all the species. By using the Sagdeev pseudo-potential technique, the allowable Mach number ranges for fast electron-acoustic solitary waves are explored and discussed. It is found that the cool and warm electron number densities determine the polarity switch of the fast electron-acoustic solitons which are limited by either the occurrence of fast electron-acoustic double layers or warm and hot electron number density becoming unreal. For the first time in the study of solitons, we report on the coexistence of fast electron-acoustic solitons, in addition to the regular fast electron-acoustic solitons and double layers in our multi-species plasma model. Our results are applied to the generation of broadband electrostatic noise in the dayside auroral region.

  11. EPR and electronic absorption spectra of copper bearing turquoise mineral

    NASA Astrophysics Data System (ADS)

    Sharma, K. B. N.; Moorthy, L. R.; Reddy, B. J.; Vedanand, S.

    1988-10-01

    Electron paramagnetic resonance and optical absorption spectra of turquoise have been studied both at room and low temperatures. It is concluded from the EPR spectra that the ground state of Cu 2+ ion in turquoise is 2A g(d x2- y2) and it is sited in an elongated rhombic octahedron (D 2π). The observed absorption bands at 14970 and 18354 cm -1 are assigned at 2A g→ 2B 1 g( dx2- y2→ xy) and 2A g→[ su2B 3g(d x 2-y 2→d yz) respectively assuming D 2π symmetry which are inconsistent with EPR studies. The three bands in the NIR region are attributed to combinations of fundamental modes of the H 2O molecule present in the sample.

  12. Cooled electronic system with liquid-cooled cold plate and thermal spreader coupled to electronic component

    DOEpatents

    Chainer, Timothy J.; Graybill, David P.; Iyengar, Madhusudan K.; Kamath, Vinod; Kochuparambil, Bejoy J.; Schmidt, Roger R.; Steinke, Mark E.

    2016-04-05

    Apparatus and method are provided for facilitating cooling of an electronic component. The apparatus includes a liquid-cooled cold plate and a thermal spreader associated with the cold plate. The cold plate includes multiple coolant-carrying channel sections extending within the cold plate, and a thermal conduction surface with a larger surface area than a surface area of the component to be cooled. The thermal spreader includes one or more heat pipes including multiple heat pipe sections. One or more heat pipe sections are partially aligned to a first region of the cold plate, that is, where aligned to the surface to be cooled, and partially aligned to a second region of the cold plate, which is outside the first region. The one or more heat pipes facilitate distribution of heat from the electronic component to coolant-carrying channel sections of the cold plate located in the second region of the cold plate.

  13. Cooled electronic system with liquid-cooled cold plate and thermal spreader coupled to electronic component

    DOEpatents

    Chainer, Timothy J.; Graybill, David P.; Iyengar, Madhusudan K.; Kamath, Vinod; Kochuparambil, Bejoy J.; Schmidt, Roger R.; Steinke, Mark E.

    2016-08-09

    Apparatus and method are provided for facilitating cooling of an electronic component. The apparatus includes a liquid-cooled cold plate and a thermal spreader associated with the cold plate. The cold plate includes multiple coolant-carrying channel sections extending within the cold plate, and a thermal conduction surface with a larger surface area than a surface area of the component to be cooled. The thermal spreader includes one or more heat pipes including multiple heat pipe sections. One or more heat pipe sections are partially aligned to a first region of the cold plate, that is, where aligned to the surface to be cooled, and partially aligned to a second region of the cold plate, which is outside the first region. The one or more heat pipes facilitate distribution of heat from the electronic component to coolant-carrying channel sections of the cold plate located in the second region of the cold plate.

  14. The biological factors influence on the conversion of mineral components of Extremely Arid Desert Soils (Kazakhstan)

    NASA Astrophysics Data System (ADS)

    Kutovaya, Olga; Vasilenko, Elena; Lebedeva, Marina; Tkhakakhova, Azida

    2013-04-01

    Extremely arid soils of stony deserts (hamadas) along the southern periphery of the Ili Depression are considered to be analogous to extremely arid soils of Mongolia, also named as "ultra-arid primitive gray-brown soils." In general, the morphology of extremely arid soils of hamadas in the Ili Depression is similar to that of the soils of stony deserts in other parts of the world, including the Gobi, Atacama, and Tarim deserts. The diagnostics of the active communities of microorganisms were performed according to the method of Rybalkina-Kononenko. The exact identification of the living forms of microorganisms to the species level is not always possible with the use of this method. However, it allows us to study the physiological role of the microorganisms and their ecological functions, including the relationships with the soil matrix and other organisms. In particular, it is possible to estimate the contribution of the microorganisms to the transformation of mineral soil components. The obtained materials allow us to conclude that the extremely arid desert soils are characterized by the very high biological activity during short periods of the increased soil moistening after rare and strong rains. The diversity of living forms is very considerable; both prokaryotes (cyanobacteria, actinomycetes, and iron bacteria) and protists (green algae, diatoms, and dinoflagellates) are developed in the soil. Thus, during a short period after the rains, these microorganisms pass from the stage of anabiosis to the stage of active growth and reproduction. Then, upon drying of the soil, the biotic activity of the soil slows down and, finally, terminates. The organisms remain in the state of anabiosis until the next rain. During the period of active growth, the microorganisms compose a specific consortium of different species and exert a profound impact on the soil properties. They participate in the transformation of the soil minerals with the formation of amorphous substances

  15. Patterns of spatial distribution of mineral components of the complex of gray forest soils Vladimir opolye

    NASA Astrophysics Data System (ADS)

    Karpova, Dina; Chizhikova, Natalya; Starokozhko, Natalya; Hadyushina, Viktorya; Korotaeva, Valentina

    2014-05-01

    The aim of the work is the analysis of spatial distribution of soil fundamental characteristics - fine fractions content (less than 1, 1-5, 5-10 and more than 10 mkm) and their mineralogical composition. The experiments were carried out on the experimental field in Suzdal region in a trench (22 m length and 2 m depth) laid in upland, well-drained conditions. Soil samples from 5 different soil profiles were collected. Fractions were obtained by Gorbunov method. Mineralogical analysis were carried out by universal X-ray diffractometer (Carl Zeiss Jena, Germany). The dominant fraction is a coarse silt fraction, the sand fraction content is negligible. The soil is characterized by medium-textured loam composition from the above and a sandy loam composition in the bottom. Textural differentiation occured due to the distribution of clay fraction. The content of this fraction in plough horizons varies depending on addition of part of other horizons during plowing. The plogh-layer of the residual-carbonate agrogrey soil is characterized by higher (20-23 %) amount of fraction less than 1 mkm, in comparison with plough horizon above the second humus horizon (SHH ), where the amount of silt is 15-16 %. The main components of the fraction derived from the rock are complex mixed- lattice formations dominated by mica - smectite with a high proportion of smectite packages, mica - smectites with low content of smectite packages were in subordinate quantity. The next component is hydromica - a mixture of dioctahedral and trioctahedral varieties. Smectite phase and hydromica add up to 85-90 % of the silt component. The amount of kaolinite and chlorite usually range in 7-13 %. Kaolinite is generally imperfect, chlorite is magnesia-ferric. The presence of fine quartz and feldspars (less amount) is revealed. During the soil formation the redistribution of the above minerals whose behavior is caused by the type of soil is occurring. Agrogrey heavy-textured soils are characterized by

  16. Emergency Dosimetry Using Ceramic Components in Personal Electronic Devices

    NASA Astrophysics Data System (ADS)

    Kouroukla, E. C.; Bailiff, I. K.; Terry, I.

    2014-02-01

    The rapid assessment of radiation dose to members of the public exposed to significant levels of ionizing radiation during a radiological incident presents a significant difficulty in the absence of planned radiation monitoring. However, within most personal electronic devices components such as resistors with alumina substrates can be found that have potentially suitable properties as solid state dosimeters using luminescence measurement techniques. The suitability of several types of ceramic-based components (e.g., resonators, inductors and resistors) has been previously examined using optically stimulated luminescence (OSL) and thermoluminescence (TL) techniques to establish their basic characteristics for the retrospective determination of absorbed dose. In this paper, we present results obtained with aluminum oxide surface mount resistors extracted from mobile phones that further extend this work. Very encouraging results have been obtained related to the measurement of luminescence sensitivity, dose response, reusability, limit of detection, signal reproducibility and known-dose recovery. However, the alumina exhibits a rapid loss of the latent luminescence signal with time following irradiation attributed to athermal (or anomalous) fading. The issues related to obtaining a reliable correction protocol for this loss and the detailed examinations required of the fading behavior are discussed.

  17. Electron Microprobe Analyses of Lithic Fragments and Their Minerals from Luna 20 Fines

    NASA Technical Reports Server (NTRS)

    Conrad, G. H.; Hlava, P. F.; Green, J. A.; Moore, R. B.; Moreland, G.; Dowty, E.; Prinz, M.; Keil, K.; Nehru, C. E.; Bunch, T. E.

    1973-01-01

    The bulk analyses (determined with the broad beam electron microprobe technique) of lithic fragments are given in weight percentages and are arranged according to the rock classification. Within each rock group the analyses are arranged in order of increasing FeO content. Thin section and lithic fragment numbers are given at the top of each column of analysis and correspond to the numbers recorded on photo mosaics on file in the Institute of Meteoritics. CIPW molecular norms are given for each analysis. Electron microprobe mineral analyses (given in oxide weight percentages), structural formulae and molecular end member values are presented for plagioclase, olivine, pyroxene and K-feldspar. The minerals are selected mostly from lithic fragments that were also analyzed for bulk composition. Within each mineral group the analyses are presented according to the section number and lithic fragment number. Within each lithic fragment the mineral analyses are arranged as follows: Plagioclase in order of increasing CaO; olivine and pyroexene in order of increasing FeO; and K-feldspar in order of increasing K2O. The mineral grains are identified at the top of each column of analysis by grain number and lithic fragment number.

  18. Trace metal and mineral speciation of remediated wastes using electron microscopy.

    PubMed

    Klich, I; Wilding, L P; Drees, L R

    2002-02-01

    Electron microscopic techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), and electron probe microanalyses (EPMA), were used to evaluate metal species and mineralogical phases associated with metal-bearing contaminated soil and industrial wastes that have been solidified and stabilized with Portland cement. Metals present in the wastes included arsenic, barium, cadmium, chromium, copper, lead, nickel, and zinc. In addition, mineral alterations and weathering features that affect the durability and containment of metals in aged remediated wastes were analyzed microscopically. Physical and chemical alteration processes identified included: freeze-thaw cracking; cracking caused by the formation of expansive minerals, such as ettringite and thaumasite; carbonation; and the movement of metals from waste aggregates into the surrounding cement matrix. Preliminary results show that although the extent of degradation after 6 years is considered slight to moderate, evaluations of durability and permanence of metals containment cannot be based on leaching and bulk chemistry analyses alone. The use of electron microscopic analyses is vital in studies that evaluate trace metal and mineral species and that attempt to predict the long-term performance of metal containment in solidified and stabilized wastes. PMID:11939530

  19. Trace metal and mineral speciation of remediated wastes using electron microscopy.

    PubMed

    Klich, I; Wilding, L P; Drees, L R

    2002-02-01

    Electron microscopic techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), and electron probe microanalyses (EPMA), were used to evaluate metal species and mineralogical phases associated with metal-bearing contaminated soil and industrial wastes that have been solidified and stabilized with Portland cement. Metals present in the wastes included arsenic, barium, cadmium, chromium, copper, lead, nickel, and zinc. In addition, mineral alterations and weathering features that affect the durability and containment of metals in aged remediated wastes were analyzed microscopically. Physical and chemical alteration processes identified included: freeze-thaw cracking; cracking caused by the formation of expansive minerals, such as ettringite and thaumasite; carbonation; and the movement of metals from waste aggregates into the surrounding cement matrix. Preliminary results show that although the extent of degradation after 6 years is considered slight to moderate, evaluations of durability and permanence of metals containment cannot be based on leaching and bulk chemistry analyses alone. The use of electron microscopic analyses is vital in studies that evaluate trace metal and mineral species and that attempt to predict the long-term performance of metal containment in solidified and stabilized wastes.

  20. 78 FR 38361 - Certain Portable Electronic Communications Devices, Including Mobile Phones and Components...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-26

    ... COMMISSION Certain Portable Electronic Communications Devices, Including Mobile Phones and Components Thereof... States after importation of certain portable electronic ] communications devices, including mobile phones... importation of certain portable electronic communications devices, including mobile phones and...

  1. Analysis of sub-micron mineral matter in coal via scanning transmission electron microscopy

    SciTech Connect

    Allen, R.M.; VanderSande, J.B.

    1982-01-01

    The Scanning Transmission Electron Microscope (STEM) is an instrument well suited for the characterization of the sub-micron sized mineral matter in coal and can also be used to identify inorganic elements atomically bound in the organic coal matrix. For the three coals studied, a random survey was taken of mineral inclusions < 100nm in mean diameter observed within coal particles in powdered coal samples. The results indicate that the predominant mineral species making up these inclusions differ from those species predominating in mineral particles at larger size ranges. Two of the coals examined showed characteristic matrix signatures of inorganic elements which were observed in greater than or equal to 90% of the matrix areas examined. The third coal did not. All three coals exhibited various elements with Z greater than or equal to 11, most notably S, which were only irregularly associated with the matrix signal (i.e., found <50% of the time). For all three coals, the predominant mineral species observed in the less than or equal to 100nm size range would not be predicted from the results of the chemical analyses of the high temperature ash of the coals. None of the major elements (Z greater than or equal to 11) observed (with the exception of sulfur in the Ba, s-rich particles) constitutes more than 10% of the HTA for the respective coals; indeed, Ba, in the lignite, Ti in the bituminous coal, and Ca in the semianthracite all make up less than 1% of the respective ashes. Encountering these elements as the major constituents in the predominant mineral species observed in a random sampling of particles <100nm in diameter indicates that the distribution of inorganic elements must not be uniform over all size ranges of mineral inclusions. In particular, for all three coals, the predominant mineral species observed in the <100nm size range must therefore differ from those species predominating at larger size ranges.

  2. Electron Transfer at the Microbe-Mineral Interface: A Grand Challenge in Biogeochemistry

    SciTech Connect

    Fredrickson, Jim K.; Zachara, John M.

    2008-06-01

    The interplay between microorganisms and minerals is a complex and dynamic process that has sculpted the geosphere for nearly the entire history of the Earth. The work of Dr. Terry Beveridge and colleagues provided some of the first insights into metal-microbe and mineral-microbe interactions and established a foundation for subsequent detailed investigations of interactions between microorganisms and minerals. Beveridge also envisioned that interdisciplinary approaches and teams would be required to explain how individual microbial cells interact with their immediate environment at nano- or sub-molecular scales and that through such approaches and using emerging technologies that the details of such interactions would be revealed at the molecular level. With this vision as incentive and inspiration, a multidisciplinary, collaborative team-based investigation was initiated to probe the process of electron transfer at the microbe-mineral interface. This grand challenge to this team was to address the hypothesis that multi-heme c-type cytochromes of dissimilatory metal reducing bacteria localized to the cell exterior function as the terminal reductases in electron transfer to Fe(III) and Mn(IV) oxides. This question has been the subject of extensive investigation for years yet the answer has remained elusive. The team involves an integrated group of experimental and computational capabilities at DOE’s Environmental Molecular Sciences Laboratory, a national scientific user facility, as the collaborative focal point. The approach involves a combination of in vitro and in vivo biologic and biogeochemical experiments and computational analyses that, when integrated, provide a conceptual model of the electron transfer process. The resulting conceptual model will be evaluated by integrating and comparing various experimental, i.e., in vitro and in vivo ET kinetics, and theoretical results. Collectively the grand challenge will provide a detailed view of how organisms

  3. Rapid electron exchange between surface-exposed bacterial cytochromes and Fe(III) minerals.

    PubMed

    White, Gaye F; Shi, Zhi; Shi, Liang; Wang, Zheming; Dohnalkova, Alice C; Marshall, Matthew J; Fredrickson, James K; Zachara, John M; Butt, Julea N; Richardson, David J; Clarke, Thomas A

    2013-04-16

    The mineral-respiring bacterium Shewanella oneidensis uses a protein complex, MtrCAB, composed of two decaheme cytochromes, MtrC and MtrA, brought together inside a transmembrane porin, MtrB, to transport electrons across the outer membrane to a variety of mineral-based electron acceptors. A proteoliposome system containing a pool of internalized electron carriers was used to investigate how the topology of the MtrCAB complex relates to its ability to transport electrons across a lipid bilayer to externally located Fe(III) oxides. With MtrA facing the interior and MtrC exposed on the outer surface of the phospholipid bilayer, the established in vivo orientation, electron transfer from the interior electron carrier pool through MtrCAB to solid-phase Fe(III) oxides was demonstrated. The rates were 10(3) times higher than those reported for reduction of goethite, hematite, and lepidocrocite by S. oneidensis, and the order of the reaction rates was consistent with those observed in S. oneidensis cultures. In contrast, established rates for single turnover reactions between purified MtrC and Fe(III) oxides were 10(3) times lower. By providing a continuous flow of electrons, the proteoliposome experiments demonstrate that conduction through MtrCAB directly to Fe(III) oxides is sufficient to support in vivo, anaerobic, solid-phase iron respiration.

  4. Rapid electron exchange between surface-exposed bacterial cytochromes and Fe(III) minerals

    NASA Astrophysics Data System (ADS)

    White, Gaye F.; Shi, Zhi; Shi, Liang; Wang, Zheming; Dohnalkova, Alice C.; Marshall, Matthew J.; Fredrickson, James K.; Zachara, John M.; Butt, Julea N.; Richardson, David J.; Clarke, Thomas A.

    2013-04-01

    The mineral-respiring bacterium Shewanella oneidensis uses a protein complex, MtrCAB, composed of two decaheme cytochromes, MtrC and MtrA, brought together inside a transmembrane porin, MtrB, to transport electrons across the outer membrane to a variety of mineral-based electron acceptors. A proteoliposome system containing a pool of internalized electron carriers was used to investigate how the topology of the MtrCAB complex relates to its ability to transport electrons across a lipid bilayer to externally located Fe(III) oxides. With MtrA facing the interior and MtrC exposed on the outer surface of the phospholipid bilayer, the established in vivo orientation, electron transfer from the interior electron carrier pool through MtrCAB to solid-phase Fe(III) oxides was demonstrated. The rates were 103 times higher than those reported for reduction of goethite, hematite, and lepidocrocite by S. oneidensis, and the order of the reaction rates was consistent with those observed in S. oneidensis cultures. In contrast, established rates for single turnover reactions between purified MtrC and Fe(III) oxides were 103 times lower. By providing a continuous flow of electrons, the proteoliposome experiments demonstrate that conduction through MtrCAB directly to Fe(III) oxides is sufficient to support in vivo, anaerobic, solid-phase iron respiration.

  5. Centimeter-long electron transport in marine sediments via conductive minerals.

    PubMed

    Malvankar, Nikhil S; King, Gary M; Lovley, Derek R

    2015-02-01

    Centimeter-long electron conduction through marine sediments, in which electrons derived from sulfide in anoxic sediments are transported to oxygen in surficial sediments, may have an important influence on sediment geochemistry. Filamentous bacteria have been proposed to mediate the electron transport, but the filament conductivity could not be verified and other mechanisms are possible. Surprisingly, previous investigations have never actually measured the sediment conductivity or its basic physical properties. Here we report direct measurements that demonstrate centimeter-long electron flow through marine sediments, with conductivities sufficient to account for previously estimated electron fluxes. Conductivity was lost for oxidized sediments, which contrasts with the previously described increase in the conductivity of microbial biofilms upon oxidation. Adding pyrite to the sediments significantly enhanced the conductivity. These results suggest that the role of conductive minerals, which are more commonly found in sediments than centimeter-long microbial filaments, need to be considered when modeling marine sediment biogeochemistry.

  6. Rapid electron exchange between surface-exposed bacterial cytochromes and Fe(III) minerals

    SciTech Connect

    White, Gaye F.; Shi, Zhi; Shi, Liang; Wang, Zheming; Dohnalkova, Alice; Marshall, Matthew J.; Fredrickson, Jim K.; Zachara, John M.; Butt, Julea N.; Richardson, David; Clarke, Thomas A.

    2013-04-16

    The mineral respiring bacterium Shewanella oneidensis uses a protein complex, MtrCAB, composed of two decaheme cytochromes brought together inside a transmembrane porin to transport electrons across the outer membrane to a variety of mineral-based electron acceptors. A proteoliposome system that contains methyl viologen as an internalised electron carrier has been used to investigate how the topology of the MtrCAB complex relates to its ability to transport electrons across a lipid bilayer to externally-located Fe(III) oxides. With MtrA facing the interior and MtrC exposed on the outer surface of the phospholipid bilayer, direct electron transfer from the interior through MtrCAB to solid-phase Fe(III) oxides was demonstrated. The observed rates of conduction through the protein complex were 2 to 3 orders of magnitude higher than that observed in whole cells, demonstrating that direct electron exchange between MtrCAB and Fe(III) oxides is efficient enough to support in-vivo, anaerobic, solid phase iron respiration.

  7. Recovery of precious metals from military electronic components

    SciTech Connect

    Gundiler, I.H.; Lutz, J.D.; Neiswander, P.G.

    1996-09-01

    Sandia National Laboratories developed a process to identify and remove the hazardous sub-components from dismantled weapons components utilizing real-time radiography and abrasive water-jet cutting. The components were then crushed, granulated, screened, and separated into an aluminium and a precious-and-base-metals fraction using air-tables. Plastics were further cleaned for disposal as non- hazardous waste.

  8. 78 FR 6130 - Certain Electronic Digital Media Devices and Components Thereof: Commission Determination To...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-29

    ... COMMISSION Certain Electronic Digital Media Devices and Components Thereof: Commission Determination To... certain electronic digital media devices and components thereof by reason of infringement of certain....usitc.gov . The public record for this investigation may be viewed on the Commission's electronic...

  9. 77 FR 68829 - Certain Electronic Digital Media Devices and Components Thereof; Notice of Request for Statements...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-16

    ... COMMISSION Certain Electronic Digital Media Devices and Components Thereof; Notice of Request for Statements... limited exclusion order against certain electronic digital media devices and components thereof imported... electronic docket (EDIS) at http://edis.usitc.gov , and will be available for inspection during...

  10. ELECTRONIC COMPONENT COOLING ALTERNATIVES: COMPRESSED AIR AND LIQUID NITROGEN

    EPA Science Inventory

    The goal of this study was to evaluate topics used to troubleshoot circuit boards with known or suspected thermally intermittent components. Failure modes for thermally intermittent components are typically mechanical defects, such as cracks in solder paths or joints, or broken b...

  11. Structural relations between collagen and mineral in bone as determined by high voltage electron microscopic tomography

    NASA Technical Reports Server (NTRS)

    Landis, W. J.; Hodgens, K. J.; Arena, J.; Song, M. J.; McEwen, B. F.

    1996-01-01

    Aspects of the ultrastructural interaction between collagen and mineral crystals in embryonic chick bone have been examined by the novel technique of high voltage electron microscopic tomography to obtain three-dimensional information concerning extracellular calcification in this tissue. Newly mineralizing osteoid along periosteal surfaces of mid-diaphyseal regions from normal chick tibiae was embedded, cut into 0.25 microns thick sections, and documented at 1.0 MV in the Albany AEI-EM7 high voltage electron microscope. The areas of the tissue studied contained electron dense mineral crystals associated with collagen fibrils, some marked by crystals disposed along their cylindrically shaped lengths. Tomographic reconstructions of one site with two mineralizing fibrils were computed from a 5 degrees tilt series of micrographs over a +/- 60 degrees range. Reconstructions showed that the mineral crystals were platelets of irregular shape. Their sizes were variable, measured here up to 80 x 30 x 8 nm in length, width, and thickness, respectively. The longest crystal dimension, corresponding to the c-axis crystallographically, was generally parallel to the collagen fibril long axis. Individual crystals were oriented parallel to one another in each fibril examined. They were also parallel in the neighboring but apparently spatially separate fibrils. Crystals were periodically (approximately 67 nm repeat distance) arranged along the fibrils and their location appeared to correspond to collagen hole and overlap zones defined by geometrical imaging techniques. The crystals appeared to be continuously distributed along a fibril, their size and number increasing in a tapered fashion from a relatively narrow tip containing smaller and infrequent crystals to wider regions having more densely packed and larger crystals. Defined for the first time by direct visual 3D imaging, these data describe the size, shape, location, orientation, and development of early crystals in normal

  12. The GfW handbook for data compilation of irradiation tested electronic components, volume 3

    NASA Astrophysics Data System (ADS)

    Wulf, F.; Braeunig, D.; Boden, A.

    1984-05-01

    Fifty-three standardized reports of spacecraft electronic components irradiation tests are presented. Statistical values are given which enable reader to evaluate the components life time in a radiative environment.

  13. 27 CFR 73.11 - What are the required components and controls for acceptable electronic signatures?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... components and controls for acceptable electronic signatures? 73.11 Section 73.11 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY (CONTINUED) PROCEDURES AND PRACTICES ELECTRONIC SIGNATURES; ELECTRONIC SUBMISSION OF FORMS Electronic Signatures §...

  14. Virtual enterprise model for the electronic components business in the Nuclear Weapons Complex

    SciTech Connect

    Ferguson, T.J.; Long, K.S.; Sayre, J.A.; Hull, A.L.; Carey, D.A.; Sim, J.R.; Smith, M.G.

    1994-08-01

    The electronic components business within the Nuclear Weapons Complex spans organizational and Department of Energy contractor boundaries. An assessment of the current processes indicates a need for fundamentally changing the way electronic components are developed, procured, and manufactured. A model is provided based on a virtual enterprise that recognizes distinctive competencies within the Nuclear Weapons Complex and at the vendors. The model incorporates changes that reduce component delivery cycle time and improve cost effectiveness while delivering components of the appropriate quality.

  15. Electronic switching circuit uses complementary non-linear components

    NASA Technical Reports Server (NTRS)

    Zucker, O. S.

    1972-01-01

    Inherent switching properties of saturable inductors and storage diodes are combined to perform large variety of electronic functions, such as pulse shaping, gating, and multiplexing. Passive elements replace active switching devices in generation of complex waveforms.

  16. Effect of electrolyte on surface free energy components of feldspar minerals using thin-layer wicking method.

    PubMed

    Karagüzel, C; Can, M F; Sönmez, E; Celik, M S

    2005-05-01

    Application of the thin-layer wicking (TLW) technique on powdered minerals is useful for characterizing their surfaces. Albite (Na-feldspar) and orthoclase (K-feldspar) are feldspar minerals which are frequently found in the same matrix. Despite similarities in their physicochemical properties, separation of these minerals from each other by flotation is generally possible in the presence of monovalent salts such as NaCl. Both albite and orthoclase exhibit the same microflotation properties and rather close electrokinetic profiles in the absence of salt. In this study, contact angles of albite and orthoclase determined by the TLW technique yielded close values in the absence and presence of amine collector. While the calculated surface energies and their components determined using contact angle data reveal that the energy terms remain farther apart in the absence of the collector, the differences narrow down at collector concentrations where full flotation recoveries are obtained. However, the effect of addition of NaCl on contact angles and surface free energy components at constant amine concentration indicates that albite is significantly affected by salt addition, whereas orthoclase remains marginally affected. This interesting finding is explained on the basis of ion-exchange properties, the stability of the interface, flotation data, and zeta potential data in the presence of NaCl.

  17. Investigation of Mineral Transformations in Wet Supercritical CO2 by Electron Microscopy

    SciTech Connect

    Arey, Bruce W.; Kovarik, Libor; Wang, Zheming; Felmy, Andrew R.

    2011-10-10

    The capture and storage of carbon dioxide and other greenhouse gases in deep geologic formations represents one of the most promising options for mitigating the impacts of greenhouse gases on global warming. In this regard, mineral-fluid interactions are of prime importance since such reactions can result in the long term sequestration of CO2 by trapping in mineral phases. Recently it has been recognized that interactions with neat to water-saturated non-aqueous fluids are of prime importance in understanding mineralization reactions since the introduced CO2 is likely to contain water initially or soon after injection and the supercritical CO2 (scCO2) is less dense than the aqueous phase which can result in a buoyant scCO2 plume contacting the isolating caprock. As a result, unraveling the molecular/microscopic mechanisms of mineral transformation in neat to water saturated scCO2 has taken on an added important. In this study, we are examining the interfacial reactions of the olivine mineral forsterite (Mg2SiO4) over a range of water contents up to and including complete water saturation in scCO2. The surface precipitates that form on the reacted forsterite grains are extremely fragile and difficult to experimentally characterize. In order to address this issue we have developed experimental protocols for preparing and imaging electron-transparent samples from fragile structures. These electron-transparent samples are then examined using a combination of STEM/EDX, FIB-TEM, and helium ion microscope (HIM) imaging (Figures 1-3). This combination of capabilities has provided unique insight into the geochemical processes that occur on scCO2 reacted mineral surfaces. The experimental procedures and protocols that have been developed also have useful applications for examining fragile structures on a wide variety of materials. This research was performed using EMSL, a national scientific user facility sponsored by the Department of Energy's Office of Biological and

  18. Abundance and distribution of mineral components associated with Moses Rock (kimberlite) diatreme

    NASA Technical Reports Server (NTRS)

    Mustard, J. F.; Pieters, C. M.

    1986-01-01

    The surface mineralogy in and around Moses Rock diatreme, a kimberlite-bearing dike in SW Utah, was examined using internally calibrated Airborne Imaging Spectrometer (AIS) data. Distinct near-infrared absorption characteristics of clays, gypsum, and serpentine (a key marker for kinberlite concentration) allowed the surface units containing these components to be identified spatially and the relative abundance of each component measured. Within the dike itself, channels and dispersed components of kimberlite and blocks of country rocks were accurately determined.

  19. Electronic Office Hours: A Component of Distance Learning.

    ERIC Educational Resources Information Center

    Wallace, F. Layne; Wallace, Susan R.

    2001-01-01

    Describes a technique to blend distance learning with traditional educational methods using electronic office hours to connect teachers and students outside the classroom. Explains the use of various existing computer mediated communication tools and techniques, including email, Usenet newsgroups, text-based conferences, video-based conferences,…

  20. Electronic Journals as a Component of the Digital Library.

    ERIC Educational Resources Information Center

    Stackpole, Laurie E.; King, Richard James

    1999-01-01

    Describes services of the Naval Research Laboratory Library that provide users in four geographical locations with digital library services, including over 500 electronic journals. Highlights include a Web-based information system, cooperative agreements, licensing, online catalogs, databases, hardware configuration, and future development.…

  1. 78 FR 34132 - Certain Portable Electronic Communications Devices, Including Mobile Phones and Components...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-06

    ... COMMISSION Certain Portable Electronic Communications Devices, Including Mobile Phones and Components Thereof... published a notice (78 FR 12892, May 31, 2013) of receipt of complaint entitled Certain Portable Electronic Communications Devices, Including Mobile Phones and Components Thereof, DN 2958; the Commission...

  2. Three Aromatic Residues are Required for Electron Transfer during Iron Mineralization in Bacterioferritin.

    PubMed

    Bradley, Justin M; Svistunenko, Dimitri A; Lawson, Tamara L; Hemmings, Andrew M; Moore, Geoffrey R; Le Brun, Nick E

    2015-12-01

    Ferritins are iron storage proteins that overcome the problems of toxicity and poor bioavailability of iron by catalyzing iron oxidation and mineralization through the activity of a diiron ferroxidase site. Unlike in other ferritins, the oxidized di-Fe(3+) site of Escherichia coli bacterioferritin (EcBFR) is stable and therefore does not function as a conduit for the transfer of Fe(3+) into the storage cavity, but instead acts as a true catalytic cofactor that cycles its oxidation state while driving Fe(2+) oxidation in the cavity. Herein, we demonstrate that EcBFR mineralization depends on three aromatic residues near the diiron site, Tyr25, Tyr58, and Trp133, and that a transient radical is formed on Tyr25. The data indicate that the aromatic residues, together with a previously identified inner surface iron site, promote mineralization by ensuring the simultaneous delivery of two electrons, derived from Fe(2+) oxidation in the BFR cavity, to the di-ferric catalytic site for safe reduction of O2.

  3. Electron microscopic examination of wastewater biofilm formation and structural components.

    PubMed Central

    Eighmy, T T; Maratea, D; Bishop, P L

    1983-01-01

    This research documents in situ wastewater biofilm formation, structure, and physiochemical properties as revealed by scanning and transmission electron microscopy. Cationized ferritin was used to label anionic sites of the biofilm glycocalyx for viewing in thin section. Wastewater biofilm formation paralleled the processes involved in marine biofilm formation. Scanning electron microscopy revealed a dramatic increase in cell colonization and growth over a 144-h period. Constituents included a variety of actively dividing morphological types. Many of the colonizing bacteria were flagellated. Filaments were seen after primary colonization of the surface. Transmission electron microscopy revealed a dominant gram-negative cell wall structure in the biofilm constituents. At least three types of glycocalyces were observed. The predominant glycocalyx possessed interstices and was densely labeled with cationized ferritin. Two of the glycocalyces appeared to mediate biofilm adhesion to the substratum. The results suggest that the predominant glycocalyx of this thin wastewater biofilm serves, in part, to: (i) enclose the bacteria in a matrix and anchor the biofilm to the substratum and (ii) provide an extensive surface area with polyanionic properties. Images PMID:6881965

  4. 78 FR 32689 - Certain Portable Electronic Communications Devices, Including Mobile Phones and Components...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-31

    ... COMMISSION Certain Portable Electronic Communications Devices, Including Mobile Phones and Components Thereof..., Including Mobile Phones and Components Thereof, DN 2958; the Commission is soliciting comments on any public... communications devices, including mobile phones and components thereof. The complaint names as respondents...

  5. 77 FR 4059 - Certain Electronic Devices for Capturing and Transmitting Images, and Components Thereof; Receipt...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-26

    ... COMMISSION Certain Electronic Devices for Capturing and Transmitting Images, and Components Thereof; Receipt... Images, and Components Thereof, DN 2869; the Commission is soliciting comments on any public interest... for capturing and transmitting images, and components thereof. The complaint names Apple Inc....

  6. 77 FR 11588 - Certain Electronic Devices for Capturing and Transmitting Images, and Components Thereof

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-27

    ... COMMISSION Certain Electronic Devices for Capturing and Transmitting Images, and Components Thereof AGENCY: U... capturing and transmitting images and components thereof by reason of infringement of certain claims of U.S... capturing and transmitting images and components thereof by reason of infringement of one or more of...

  7. [Age-related changes of the mineral component content in the hemolymph of 2d- and 3d-stage larvae of the reindeer warble fly (Hypodermatidae)].

    PubMed

    Borozdina, N I

    1979-01-01

    A mineral components concentration in the haemolymph of the IInd- and IIIrd-stage larvae of Oedemagena tarandi depends on the physiological state of parasites. Metabolism of mineral components is most intensive in a young actively growing organism and during moulting. The moulting is characterized by the decrease in the concentration of inorganic phosphorus and potassium and by the increase of calcium, magnesium and natrium.

  8. Composition and method for removing photoresist materials from electronic components

    DOEpatents

    Davenhall, Leisa B.; Rubin, James B.

    2002-01-01

    The invention is a combination of at least one dense phase fluid and at least one dense phase fluid modifier which can be used to contact substrates for electronic parts such as semiconductor wafers or chips to remove photoresist materials which are applied to the substrates during manufacture of the electronic parts. The dense phase fluid modifier is one selected from the group of cyclic, aliphatic or alicyclic compounds having the functional group: ##STR1## wherein Y is a carbon, oxygen, nitrogen, phosphorus or sulfur atom or a hydrocarbon group having from 1 to 10 carbon atoms, a halogen or halogenated hydrocarbon group having from 1 to 10 carbon atoms, silicon or a fluorinated silicon group; and wherein R.sub.1 and R.sub.2 can be the same or different substituents; and wherein, as in the case where X is nitrogen, R.sub.1 or R.sub.2 may not be present. The invention compositions generally are applied to the substrates in a pulsed fashion in order to remove the hard baked photoresist material remaining on the surface of the substrate after removal of soft baked photoresist material and etching of the barrier layer.

  9. Pulmonary epithelial response in the rat lung to instilled Montserrat respirable dusts and their major mineral components

    PubMed Central

    Housley, D; Berube, K; Jones, T; Anderson, S; Pooley, F; Richards, R

    2002-01-01

    Background: The Soufriere Hills, a stratovolcano on Montserrat, started erupting in July 1995, producing volcanic ash, both from dome collapse pyroclastic flows and phreatic explosions. The eruptions/ash resuspension result in high concentrations of suspended particulate matter in the atmosphere, which includes cristobalite, a mineral implicated in respiratory disorders. Aims: To conduct toxicological studies on characterised samples of ash, together with major components of the dust mixture (anorthite, cristobalite), and a bioreactive mineral control (DQ12 quartz). Methods: Rats were challenged with a single mass (1 mg) dose of particles via intratracheal instillation and groups sacrificed at one, three, and nine weeks. Acute bioreactivity of the particles was assessed by increases in lung permeability and inflammation, changes in epithelial cell markers, and increase in the size of bronchothoracic lymph nodes. Results: Data indicated that respirable ash derived from pyroclastic flows (20.1% cristobalite) or phreatic explosion (8.6% cristobalite) had minimal bioreactivity in the lung. Anorthite showed low bioreactivity, in contrast to pure cristobalite, which showed progressive increases in lung damage. Conclusion: Results suggests that either the percentage mass of cristobalite particles present in Montserrat ash was not sufficient as a catalyst in the lung environment, or its surface reactivity was masked by the non-reactive volcanic glass components during the process of ash formation. PMID:12107295

  10. A gyro-oriented 3-component borehole magnetometer for mineral prospecting, with examples of its application

    SciTech Connect

    Bosum, W.; Eberle, D.; Rehli, H.J.

    1988-11-01

    A triple axis borehole magnetometer is described that consists of a Foerster-probe (fluxgate) triplet (sensitivity 1 nT), a Foerster-probe gradiometer (sensitivity 2 nT/40 cm), a gyro unit (mean angular drift approx 0.5/sup 0//h) which is equipped with accelerometers (sensitivity 1/100/sup 0/), and a data transmission unit (with multiplexer and 16-bit AD converter). The sensitive fluxgate-magnetometer can detect weakly magnetic or small source bodies. Data from the gyro and the accelerometers allow the 3-component magnetic field values to be transformed to north, east and vertical components. Since they do not rely on magnetically-determined directional data, the results are not disturbed by local anomalies of the magnetic declination. Furthermore, the magnetometer can also be used in vertical boreholes. 3-component measurements are carried out at discrete points in the neighbourhood of a source body to locate its position, and within the source body to determine the direction of magnetization. The strength of magnetization and information on magnetic classification are obtained by continuous measurement of one or more components within the source body. Calculation algorithms and computer programs are available to simplify data processing and interpretation. Survey examples are discussed.

  11. The Composition of Bovine Peritubular Dentin: Matching TOF-SIMS, Scanning Electron Microscopy and Biochemical Component Distributions

    PubMed Central

    Gotliv, Bat Ami; Veis, Arthur

    2008-01-01

    Peritubular dentin (PTD) is a hypermineralized phase within the dentinal tubules in some vertebrate teeth as an interface between the intertubular dentin (ITD) and the cell processes. Our aim has been to understand the composition, structure and role of PTD as a mineralized tissue. We have utilized the technique of time of flight secondary ion mass spectrometry (TOF-SIMS) to map the distribution of positive and negative inorganic ions as well as organic components in the fully mineralized, intact PTD structure in bovine tooth cross-sections, and correlated these with scanning electron microscopy (SEM) in standard and backscatter modes. In recent work, we developed a procedure to freeze fracture the teeth and separate PTD from the less dense ITD by the use of aqueous sodium phosphotungstate step density gradients, after degrading the ITD collagen with NaOCl. Here, PTD-containing fragments were characterized by SEM and TOF-SIMS surface structure analysis. The TOF-SIMS data show that the isolated PTD does not contain collagen, but its surface is rich in glutamic acid-containing protein(s). The TOF-SIMS spectra also indicated that the intact PTD fragments contain phospholipids, and chemical analyses showed phosphatidylserine, phosphatidylinositol and phosphatidylcholine as the principal lipid components. In SEM sections, untreated PTD shows as a smooth collar around the tubule, but after digestion with ethylenediamine to remove all organic components, the porous nature of the mineral phase of small, thin platy apatite crystals becomes evident. Thus, the organic matrix of PTD appears to be a proteolipid-phospholipid complex. PMID:18728348

  12. An overview of the NASA electronic components information management system

    NASA Technical Reports Server (NTRS)

    Kramer, G.; Waterbury, S.

    1991-01-01

    The NASA Parts Project Office (NPPO) comprehensive data system to support all NASA Electric, Electronic, and Electromechanical (EEE) parts management and technical data requirements is described. A phase delivery approach is adopted, comprising four principal phases. Phases 1 and 2 support Space Station Freedom (SSF) and use a centralized architecture with all data and processing kept on a mainframe computer. Phases 3 and 4 support all NASA centers and projects and implement a distributed system architecture, in which data and processing are shared among networked database servers. The Phase 1 system, which became operational in February of 1990, implements a core set of functions. Phase 2, scheduled for release in 1991, adds functions to the Phase 1 system. Phase 3, to be prototyped beginning in 1991 and delivered in 1992, introduces a distributed system, separate from the Phase 1 and 2 system, with a refined semantic data model. Phase 4 extends the data model and functionality of the Phase 3 system to provide support for the NASA design community, including integration with Computer Aided Design (CAD) environments. Phase 4 is scheduled for prototyping in 1992 to 93 and delivery in 1994.

  13. Porous tantalum tibial component prevents periprosthetic loss of bone mineral density after total knee arthroplasty for five years-a matched cohort study.

    PubMed

    Minoda, Yukihide; Kobayashi, Akio; Ikebuchi, Mitsuhiko; Iwaki, Hiroyoshi; Inori, Fumiaki; Nakamura, Hiroaki

    2013-12-01

    In 21 knees receiving porous tantalum tibial component and 21 knees receiving a cemented cobalt-chromium tibial component, dual x-ray absorptiometry scans were performed for five years post-operatively. The postoperative decrease in the bone mineral density in the lateral aspect of the tibia was significantly less in knees with porous tantalum tibial components (11.6%) than in knees with cemented cobalt-chromium tibial components (29.6%) at five years (p < 0.05). No prosthetic migration or periprosthetic fracture was detected in either group. The present study is one of the studies with the longest follow-up period on bone mineral density after total knee arthroplasty. Porous tantalum tibial component has a favorable effect on the bone mineral density of the proximal tibia after total knee arthroplasty up to five years.

  14. Application of Quantitative Analytical Electron Microscopy to the Mineral Content of Insect Cuticle

    NASA Astrophysics Data System (ADS)

    Rasch, Ron; Cribb, Bronwen W.; Barry, John; Palmer, Christopher M.

    2003-04-01

    Quantification of calcium in the cuticle of the fly larva Exeretonevra angustifrons was undertaken at the micron scale using wavelength dispersive X-ray microanalysis, analytical standards, and a full matrix correction. Calcium and phosphorus were found to be present in the exoskeleton in a ratio that indicates amorphous calcium phosphate. This was confirmed through electron diffraction of the calcium-containing tissue. Due to the pragmatic difficulties of measuring light elements, it is not uncommon in the field of entomology to neglect the use of matrix corrections when performing microanalysis of bulk insect specimens. To determine, firstly, whether such a strategy affects the outcome and secondly, which matrix correction is preferable, phi-rho (z) and ZAF matrix corrections were contrasted with each other and without matrix correction. The best estimate of the mineral phase was found to be given by using the phi-rho (z) correction. When no correction was made, the ratio of Ca to P fell outside the range for amorphous calcium phosphate, possibly leading to flawed interpretation of the mineral form when used on its own.

  15. Apollo 15 rake sample microbreccias and non-mare rocks: Bulk rock, mineral and glass electron microprobe analyses

    NASA Technical Reports Server (NTRS)

    Hlava, P. F.; Green, J. A.; Prinz, M.; Nehru, C. E.; Keil, K.; Dowty, E.; Bunch, T. E.

    1972-01-01

    Quantitative electron microprobe data of Apollo 15 nonmare rake samples are presented. Bulk analyses of lithic fragments in the nomare rocks (expressed in oxide weight-percent) and the corresponding CIPW molecular norms are given. The mineralogy of the rocks and lithic fragments are also given; structural formulae for complete analyses and molecular end-members for all mineral analyses are included. The mineral analyses include pyroxene, olivine, plagioclase, barian K-feldspar, spinel and ilmenite, cobaltian metallic nickel-iron as well as SiO2-K2O-rich residual glass. Electron micropobe analyses (oxide weight percent) of glasses in loose fines and microbreccia samples and their CIPW molecular norms are presented along with electron microprobe data on bulk, mineral, and matrix glass from chondrules.

  16. 78 FR 63492 - Certain Electronic Devices, Including Mobile Phones and Tablet Computers, and Components Thereof...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-24

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Certain Electronic Devices, Including Mobile Phones and Tablet Computers, and Components Thereof; Notice of Request for Statements on the Public Interest AGENCY: U.S. International Trade...

  17. Extending Ball and Stick Models by Using Three-Center, Two-Electron Bonding Components.

    ERIC Educational Resources Information Center

    Jensen, William B.

    1980-01-01

    Described is a method of utilizing the standard ball and stick models, used in demonstrating molecular structure, for building two electron bonding components. Included is the construction of several molecules with word and picture descriptions. (Author/DS)

  18. THREE-COMPONENT BOREHOLE MAGNETOMETER PROBE FOR MINERAL INVESTIGATIONS AND GEOLOGIC RESEARCH.

    USGS Publications Warehouse

    Scott, James H.; Olson, Gary G.

    1985-01-01

    A small-diameter three-component fluxgate magnetometer probe with gyroscopic and inclinometer orientation has been developed to meet U. S. Geological Survey design and performance specifications for measurement of the direction and intensity of the Earth's magnetic field in vertical and inclined boreholes. The orthogonal fluxgate magnetometer elements have a measurement resolution of 10 nanoteslas (nT) and a range of plus or minus 80,000 nT. The gyroscope has an effective resolution of one degree, and the orthogonal inclinometers, 0. 1 degree. The magnetometer probe has been field tested in several holes drilled through volcanic rocks in Nevada. Results indicate that reversals of polarization can be detected, and some rock units in this area appear to be characterized by unique magnetic signatures.

  19. Radiation studies of optical and electronic components used in astronomical satellite studies

    NASA Technical Reports Server (NTRS)

    Becher, J.; Kernell, R. L.

    1981-01-01

    The synchronous orbit of the IUE carries the satellite through Earth's outer electron belt. A 40 mCi Sr90 source was used to simulate these electrons. A 5 mCi source of Co60 was used to simulate bremmstrahlung. A 10 MeV electron Linac and a 1.7 MeV electron Van de Graaf wer used to investigate the energy dependence of radiation effects and to perform radiations at a high flux rate. A 100 MeV proton cyclotron was used to simulate cosmic rays. Results are presented for three instrument systems of the IUE and measurements for specific components are reported. The three instrument systems were the ultraviolet converter, the fine error sensor (FES), and the SEC vidicon camera tube. The components were optical glasses, electronic components, silicon photodiodes, and UV window materials.

  20. Spectroscopic evidence for Fe(II)-Fe(III) electron transfer at clay mineral edge and basal sites.

    PubMed

    Neumann, Anke; Olson, Tyler L; Scherer, Michelle M

    2013-07-01

    Despite the importance of Fe redox cycling in clay minerals, the mechanism and location of electron transfer remain unclear. More specifically, there is some controversy whether electron transfer can occur through both basal and edge surfaces. Here we used Mössbauer spectroscopy combined with selective chemical extractions to study electron transfer from Fe(II) sorbed to basal planes and edge OH-groups of clay mineral NAu-1. Fe(II) sorbed predominantly to basal planes at pH values below 6.0 and to edge OH-groups at pH value 7.5. Significant electron transfer occurred from edge OH-group bound Fe(II) at pH 7.5, whereas electron transfer from basal plane-sorbed Fe(II) to structural Fe(III) in clay mineral NAu-1 at pH 4.0 and 6.0 occurred but to a much lower extent than from edge-bound Fe(II). Mössbauer hyperfine parameters for Fe(II)-reacted NAu-1 at pH 7.5 were consistent with structural Fe(II), whereas values found at pH 4.0 and 6.0 were indicative of binding environments similar to basal plane-sorbed Fe(II). Reference experiments with Fe-free synthetic montmorillonite SYn-1 provided supporting evidence for the assignment of the hyperfine parameters to Fe(II) bound to basal planes and edge OH-groups. Our findings demonstrate that electron transfer to structural Fe in clay minerals can occur from Fe(II) sorbed to both basal planes and edge OH-groups. These findings require us to reassess the mechanisms of abiotic and microbial Fe reduction in clay minerals as well as the importance of Fe-bearing clay minerals as a renewable source of redox equivalents in subsurface environments.

  1. Strength of mineral absorption features in the transmitted component of near-infrared reflected light - First results from RELAB

    NASA Astrophysics Data System (ADS)

    Pieters, C. M.

    1983-11-01

    Bidirectional reflectance measurements are the only type of reflectance data available to the remote observer. For compositional interpretations, data are desired not only for identification of possible mineral components but also for modal abundance. The latter requires detailed information about the strength of absorption features. Using a new laboratory facility, the RELAB, laboratory data in the near infrared are presented that document effects of particle size, mineral mixtures, and viewing geometry for selected materials with well-developed absorption bands. The commonly observed increase in reflectance with decrease in particle size is also observed for absorption bands as well as a related decrease in absorption strength. For small particles in parts of the spectrum of maximum reflectance, however, a minor decrease in reflectance with a decrese in particle size is sometimes observed. Small particles dominate the observed characteristics of particulate surfaces, which contain a range of particle sizes. The mean optical path length (transmission through particles) of reflected radiation measured for a variety of particle sizes has an apparent upper limit of about 2 mm for particles of less than 250 microns. The typical number of particles involved in the optical path is less than 50.

  2. Spatial distribution of mineral components in microcombinations of agrogrey soils with the second humus horizon in the Vladimir opolie area

    NASA Astrophysics Data System (ADS)

    Chizhikova, N. P.; Karpova, D. V.

    2016-09-01

    Mineralogical composition of silt and clay fractions (<1.1-5 and 5-10 µm) in heavy loamy agrogrey soils (Luvic Retic Phaeozems) considerably changes both in the vertical (along the soil profile) and horizontal (along soil microcatenas) directions. The eluvial-illuvial distribution pattern of the clay fraction in the podzolized agrogrey soils with the second humus horizon is replaced by the homogeneous distribution in the agrogrey soils with residual carbonates. The distribution of silt fractions in the soil profiles is relatively homogeneous. The clay (<1 µm) fraction of the parent material is represented by the poorly ordered micasmectite interstratifications minerals, the proportion between which changes in the soil profiles in dependence on the particular pedogenetic processes. Hydromicas represent the second important component of the clay fraction. They consist of di- and trioctahedral varieties, the proportion between which changes in the soil profiles. Kaolinite and iron-magnesium chlorite are present in smaller amounts. The second humus horizon is characterized by the lowest content of mica-smectite interstratifications minerals with the high content of smectitic layers and by the lowest content of the clay fraction. Silt fractions are composed of quartz, micas, potassium feldspars, and plagioclases.

  3. 78 FR 16531 - Certain Electronic Devices for Capturing and Transmitting Images, and Components Thereof...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-15

    ... Eastman Kodak Company of Rochester, New York. 77 FR 11588-89 (Feb. 27, 2012). The complaint alleges a... COMMISSION Certain Electronic Devices for Capturing and Transmitting Images, and Components Thereof... images, and components thereof. The complaint further alleges that an industry in the United...

  4. Mineral and organic matrix interaction in normally calcifying tendon visualized in three dimensions by high-voltage electron microscopic tomography and graphic image reconstruction

    NASA Technical Reports Server (NTRS)

    Landis, W. J.; Song, M. J.; Leith, A.; McEwen, L.; McEwen, B. F.

    1993-01-01

    To define the ultrastructural accommodation of mineral crystals by collagen fibrils and other organic matrix components during vertebrate calcification, electron microscopic 3-D reconstructions were generated from the normally mineralizing leg tendons from the domestic turkey, Meleagris gallopavo. Embedded specimens containing initial collagen mineralizing sites were cut into 0.5-micron-thick sections and viewed and photographed at 1.0 MV in the Albany AEI-EM7 high-voltage electron microscope. Tomographic 3-D reconstructions were computed from a 2 degree tilt series of micrographs taken over a minimum angular range of +/- 60 degrees. Reconstructions of longitudinal tendon profiles confirm the presence of irregularly shaped mineral platelets, whose crystallographic c-axes are oriented generally parallel to one another and directed along the collagen long axes. The reconstructions also corroborate observations of a variable crystal length (up to 170 nm measured along crystallographic c-axes), the presence of crystals initially in either the hole or overlap zones of collagen, and crystal growth in the c-axis direction beyond these zones into adjacent overlap and other hole regions. Tomography shows for the first time that crystal width varies (30-45 nm) but crystal thickness is uniform (approximately 4-6 nm at the resolution limit of tomography); more crystals are located in the collagen hole zones than in the overlap regions at the earliest stages of tendon mineralization; the crystallographic c-axes of the platelets lie within +/- 15-20 degrees of one another rather than being perfectly parallel; adjacent platelets are spatially separated by a minimum of 4.2 +/- 1.0 nm; crystals apparently fuse in coplanar alignment to form larger platelets; development of crystals in width occurs to dimensions beyond single collagen hole zones; and a thin envelope of organic origin may be present along or just beneath the surfaces of individual mineral platelets. Implicit in the

  5. Investigating Microbe-Mineral Interactions: Recent Advances in X-Ray and Electron Microscopy and Redox-Sensitive Methods

    NASA Astrophysics Data System (ADS)

    Miot, Jennyfer; Benzerara, Karim; Kappler, Andreas

    2014-05-01

    Microbe-mineral interactions occur in diverse modern environments, from the deep sea and subsurface rocks to soils and surface aquatic environments. They may have played a central role in the geochemical cycling of major (e.g., C, Fe, Ca, Mn, S, P) and trace (e.g., Ni, Mo, As, Cr) elements over Earth's history. Such interactions include electron transfer at the microbe-mineral interface that left traces in the rock record. Geomicrobiology consists in studying interactions at these organic-mineral interfaces in modern samples and looking for traces of past microbe-mineral interactions recorded in ancient rocks. Specific tools are required to probe these interfaces and to understand the mechanisms of interaction between microbes and minerals from the scale of the biofilm to the nanometer scale. In this review, we focus on recent advances in electron microscopy, in particular in cryoelectron microscopy, and on a panel of electrochemical and synchrotron-based methods that have recently provided new understanding and imaging of the microbe-mineral interface, ultimately opening new fields to be explored.

  6. Redox linked flavin sites in extracellular decaheme proteins involved in microbe-mineral electron transfer.

    DOE PAGES

    Edwards, Marcus J.; White, Gaye F.; Norman, Michael; Tome-Fernandez, Alice; Ainsworth, Emma; Shi, Liang; Fredrickson, Jim K.; Zachara, John M.; Butt, Julea N.; Richardson, David J.; et al

    2015-07-01

    Extracellular microbe-mineral electron transfer is a major driving force for the oxidation of organic carbon in many subsurface environments. Extracellular multi-heme cytochromes of the Shewenella genus play a major role in this process but the mechanism of electron exchange at the interface between cytochrome and acceptor is widely debated. The 1.8 Å x-ray crystal structure of the decaheme MtrC revealed a highly conserved CX₈C disulfide that, when substituted for AX₈A, severely compromised the ability of S. oneidensis to grow under aerobic conditions. Reductive cleavage of the disulfide in the presence of flavin mononucleotide (FMN) resulted in the reversible formation ofmore » a stable flavocytochrome. Similar results were also observed with other decaheme cytochromes, OmcA, MtrF and UndA. The data suggest that these decaheme cytochromes can transition between highly reactive flavocytochromes or less reactive cytochromes, and that this transition is controlled by a redox active disulfide that responds to the presence of oxygen.« less

  7. Redox linked flavin sites in extracellular decaheme proteins involved in microbe-mineral electron transfer.

    SciTech Connect

    Edwards, Marcus J.; White, Gaye F.; Norman, Michael; Tome-Fernandez, Alice; Ainsworth, Emma; Shi, Liang; Fredrickson, Jim K.; Zachara, John M.; Butt, Julea N.; Richardson, David J.; Clarke, Thomas A.

    2015-07-01

    Extracellular microbe-mineral electron transfer is a major driving force for the oxidation of organic carbon in many subsurface environments. Extracellular multi-heme cytochromes of the Shewenella genus play a major role in this process but the mechanism of electron exchange at the interface between cytochrome and acceptor is widely debated. The 1.8 Å x-ray crystal structure of the decaheme MtrC revealed a highly conserved CX₈C disulfide that, when substituted for AX₈A, severely compromised the ability of S. oneidensis to grow under aerobic conditions. Reductive cleavage of the disulfide in the presence of flavin mononucleotide (FMN) resulted in the reversible formation of a stable flavocytochrome. Similar results were also observed with other decaheme cytochromes, OmcA, MtrF and UndA. The data suggest that these decaheme cytochromes can transition between highly reactive flavocytochromes or less reactive cytochromes, and that this transition is controlled by a redox active disulfide that responds to the presence of oxygen.

  8. Redox Linked Flavin Sites in Extracellular Decaheme Proteins Involved in Microbe-Mineral Electron Transfer.

    PubMed Central

    Edwards, Marcus J.; White, Gaye F.; Norman, Michael; Tome-Fernandez, Alice; Ainsworth, Emma; Shi, Liang; Fredrickson, Jim K.; Zachara, John M.; Butt, Julea N.; Richardson, David J.; Clarke, Thomas A.

    2015-01-01

    Extracellular microbe-mineral electron transfer is a major driving force for the oxidation of organic carbon in many subsurface environments. Extracellular multi-heme cytochromes of the Shewenella genus play a major role in this process but the mechanism of electron exchange at the interface between cytochrome and acceptor is widely debated. The 1.8 Å x-ray crystal structure of the decaheme MtrC revealed a highly conserved CX8C disulfide that, when substituted for AX8A, severely compromised the ability of S. oneidensis to grow under aerobic conditions. Reductive cleavage of the disulfide in the presence of flavin mononucleotide (FMN) resulted in the reversible formation of a stable flavocytochrome. Similar results were also observed with other decaheme cytochromes, OmcA, MtrF and UndA. The data suggest that these decaheme cytochromes can transition between highly reactive flavocytochromes or less reactive cytochromes, and that this transition is controlled by a redox active disulfide that responds to the presence of oxygen. PMID:26126857

  9. Critical density for Landau damping in a two-electron-component plasma

    SciTech Connect

    Rupp, Constantin F.; López, Rodrigo A.; Araneda, Jaime A.

    2015-10-15

    The asymptotic evolution of an initial perturbation in a collisionless two-electron-component plasma with different temperatures is studied numerically. The transition between linear and nonlinear damping regimes is determined by slowly varying the density of the secondary electron-component using high-resolution Vlasov-Poisson simulations. It is shown that, for fixed amplitude perturbations, this transition behaves as a critical phenomenon with time scales and field amplitudes exhibiting power-law dependencies on the threshold density, similar to the critical amplitude behavior in a single-component plasma.

  10. Effect of Three-year Multi-Component Exercise Training on Bone Mineral Density and Content in a Postmenopausal Woman with Osteoporosis: A Case Report.

    PubMed

    Movaseghi, Farzaneh; Sadeghi, Heydar

    2015-05-01

    The purpose of the present study was to examine the effect of 3-years of moderate multi-component exercise training on bone mineral density and bone mineral content in a female subject with osteoporosis. A 57-year-old postmenopausal woman, a known case of osteoporosis following an accident, participated in this study. Bone mineral density and bone mineral content was measured in the femoral neck area and the lumbar spine by dual energy X-ray absorptiometry. The measurements lasted four years, first year without any exercise training and three succeeding years with exercise intervention. After three years of exercise training, bone mineral density and bone mineral content were improved in both regions, despite the increase in age and decrease in weight. This case highlights the importance of exercise training in maintaining and increasing bone mineral density and bone mineral content of the spine and hip in post-menopausal women. Considering its positive effects, regular and lifelong exercise training must be incorporated into peoples' life due to the chronic nature of bone loss in aging process.

  11. Ulysses observations of electron and proton components in a magnetic cloud and related wave activity

    NASA Technical Reports Server (NTRS)

    Osherovich, V. A.; Fainberg, J.; Stone, R. G.; MacDowall, R. J.; Phillips, J. L.; Balogh, A.

    1995-01-01

    In addition to a smooth rotation of the magnetic field vector, magnetic clouds have a low proton temperature T(sub p). Their expansion in the solar wind leads to depletion and therefore the ion component cools down. It has been shown recently that the electron component in magnetic clouds behaves differently: when the cloud expands, electron temperature Te anti correlates with density and therefore Te increases in the cloud, creating favorable conditions for the rise of ion-acoustic waves. For the magnetic cloud observed by Ulysses on June 10 - 12, 1993 at 4.64 AU at S 32.5 deg, we present observations for both electron and proton components and related plasma wave activity. Our results confirm the anti correlation between T(sub e) and electron density and also exhibit a high ratio of T(sub e)/T(sub P) in the cloud. Since Landau damping is not effective for T(sub e)/T(sub p) much greater than 1, Doppler shifted ion acoustic waves are expected in the cloud. Calculation of ion acoustic wave frequencies in the cloud and comparison with observed wave activity confirm this expectation. As in our previous work, we show that the electron component in the cloud obeys a polytropic law with gamma is less than 1 (gamma approximately equals 0.3-0.4). The dynamics of the magnetic cloud are determined to a large degree by the dominating electron pressure.

  12. The use of the scanning electron microscope in the determination of the mineral composition of Ballachulish slate

    SciTech Connect

    Walsh, Joan A.

    2007-11-15

    Slate is a fine-grained, low-grade metamorphic rock derived from argillaceous sediments or occasionally volcanic ash. Although most slates contain mainly quartz, chlorite and white mica, they vary considerably in their durability, some lasting centuries while others fail after a few years of service. A detailed characterisation of their mineralogy is required for the assessment of performance, and to establish the provenance of a used slate. A combination of methods was used to examine Ballachulish slates; XRD analysis to determine the principal minerals present, XRF analysis to determine the total chemical composition, and scanning electron microscopy to determine the chemical composition of individual minerals. It was found that the white mica in Ballachulish slate is phengite and the chlorite is ripidolite. Feldspar is present as albite and carbonate as ferroan dolomite. Several accessory minerals were also identified, including chloritoid, monzonite and zircon. There was considerable variation in the ratio of the principal minerals, making it impossible to identify used slates by this criterion. Instead, chemical composition of the individual minerals, and possibly key accessory minerals, should be used to determine the provenance of slates.

  13. Electron paramagnetic resonance of natural and gamma-irradiated alunite and kaolin mineral powders

    NASA Astrophysics Data System (ADS)

    Koksal, F.; Koseoglu, R.; Saka, I.; Basaran, E.; Sener, F.

    2004-06-01

    Natural alunite and kaolin minerals obtained from West Anatolia were investigated by electron paramagnetic resonance (EPR) in natural and gamma-irradiated states at room temperature and at 113 K. The paramagnetic centres at ambient temperature in natural alunite were attributed to the (C) over dot H 2OH, (C) over dot O-3(-), (S) over dot O-2(-), (C) over dot O-2(-) and [AlO4 ](0) radicals. In natural kaolin, the paramagnetic centres were attributed to the (C) over dot O-3(-), (S) over dot O-2(-) (C) over dot O-2(-) and [AlO4](0) radicals. The gamma-irradiation does not produce any detectable effects on these radicals. At 113 K, the lines for (C) over dot H2OH could not be observed well, probably due to the anisotropic behaviour of the hyperfine interaction of the methylene protons, but the lines for [AlO4](0) centres were found to be perfectly observable at above 20 mW microwave power in both alunite and kaolin powders before and after gamma-irradiation. The EPR parameters of the observed paramagnetic centres were reported.

  14. Thermoelectric-enhanced, liquid-based cooling of a multi-component electronic system

    SciTech Connect

    Chainer, Timothy J; Graybill, David P; Iyengar, Madhusudan K; Kamath, Vinod; Kochuparambil, Bejoy J; Schmidt, Roger R; Steinke, Mark E

    2015-05-12

    Apparatus and method are provided for facilitating cooling of an electronic component. The apparatus includes a liquid-cooled structure, a thermal conduction path coupling the electronic component and the liquid-cooled structure, a coolant loop in fluid communication with a coolant-carrying channel of the liquid-cooled structure, and an outdoor-air-cooled heat exchange unit coupled to facilitate heat transfer from the liquid-cooled structure via, at least in part, the coolant loop. The thermoelectric array facilitates transfer of heat from the electronic component to the liquid-cooled structure, and the heat exchange unit cools coolant passing through the coolant loop by dissipating heat from the coolant to outdoor ambient air. In one implementation, temperature of coolant entering the liquid-cooled structure is greater than temperature of the outdoor ambient air to which heat is dissipated.

  15. Thermoelectric-enhanced, liquid-based cooling of a multi-component electronic system

    SciTech Connect

    Chainer, Timothy J; Graybill, David P; Iyengar, Madhusudan K; Kamath, Vinod; Kochuparambil, Bejoy J; Schmidt, Roger R; Steinke, Mark E

    2015-11-10

    Methods are provided for facilitating cooling of an electronic component. The methods include providing: a liquid-cooled structure, a thermal conduction path coupling the electronic component and the liquid-cooled structure, a coolant loop in fluid communication with a coolant-carrying channel of the liquid-cooled structure, and an outdoor-air-cooled heat exchange unit coupled to facilitate heat transfer from the liquid-cooled structure via, at least in part, the coolant loop. The thermoelectric array facilitates transfer of heat from the electronic component to the liquid-cooled structure, and the heat exchange unit cools coolant passing through the coolant loop by dissipating heat from the coolant to outdoor ambient air. In one implementation, temperature of coolant entering the liquid-cooled structure is greater than temperature of the outdoor ambient air to which heat is dissipated.

  16. Analysis of electron spin resonance spectra of irradiated gingers: Organic radical components derived from carbohydrates

    NASA Astrophysics Data System (ADS)

    Yamaoki, Rumi; Kimura, Shojiro; Ohta, Masatoshi

    2010-04-01

    Electron spin resonance (ESR) spectral characterizations of gingers irradiated with electron beam were studied. Complex asymmetrical spectra (near g=2.005) with major spectral components (line width=2.4 mT) and minor signals (at 6 mT apart) were observed in irradiated gingers. The spectral intensity decreased considerably 30 days after irradiation, and continued to decrease steadily thereafter. The spectra simulated on the basis of characteristics of free radical components derived from carbohydrates in gingers are in good agreement with the observed spectra. Analysis showed that shortly after irradiation the major radical components of gingers were composed of radical species derived from amylose and cellulose, and the amylose radicals subsequently decreased considerably. At 30 days after irradiation, the major radical components of gingers were composed of radical species derived from cellulose, glucose, fructose or sucrose.

  17. Melt rock components in KREEPy breccia 15205: Petrography and mineral chemistry of KREEP basalts and quartz-normative mare basalts

    NASA Technical Reports Server (NTRS)

    Shervais, John W.; Vetter, Scott K.

    1993-01-01

    Many current models for the origin of lunar highland rocks feature as an essential component the assimilation of KREEPy material by primitive magmas parental to the Mg-rich suite and alkali suite plutonic rocks. Similar models have also been proposed for the origin of various mare basalt suites. However, any model which considers assimilation of KREEP an important petrologic process must sooner-or-later deal with the question: what is KREEP? Because pristine KREEP basalts are rare, and most known samples are small (e.g., 15382/15386), the geochemical variability of KREEP basalts is poorly known. Other KREEP compositions which are commonly used in these models include the hypothetical 'high-K KREEP' component of Warren and Wasson, which is derived from Apollo 14 soil data, and the 'superKREEP' quartz-monzodiorite 15405. Lunar breccia 15205 is a polymict regolith breccia that consists of approximately 20% KREEP basalt clasts and 20% quartz-normative basalt clasts in a KREEP-rich matrix. Bulk rock mixing calculations show that this sample comprises about 84% KREEP. The clasts range up to 1 cm in size, but most are considerably smaller. The primary aim is to characterize pristine KREEP basalts petrographically, to establish the range in chemical compositions of KREEP basalts, and to test models that were proposed for their origin. In addition, we may be able to extend the compositional range recognized in the quartz-normative basalt suite and cast some light on its origin as well. Preliminary whole rock geochemical data on the KREEP basalts are presented in a companion paper by M.M. Lindstrom and co-workers. Concentration is on petrography and mineral chemistry of these clasts, and the implications these data have for the origin of the different melt rock suites.

  18. Linear electrostatic waves in a three-component electron-positron-ion plasma

    SciTech Connect

    Mugemana, A. Moolla, S.; Lazarus, I. J.

    2014-12-15

    Analytical linear electrostatic waves in a magnetized three-component electron-positron-ion plasma are studied in the low-frequency limit. By using the continuity and momentum equations with Poisson's equation, the dispersion relation for the electron-positron-ion plasma consisting of cool ions, and hot Boltzmann electrons and positrons is derived. In the linear regime, the propagation of two possible modes and their evolution are studied. In the cases of parallel and perpendicular propagation, it is shown that these two possible modes are always stable. The present investigation contributes to nonlinear propagation of electrostatic waves in space and the laboratory.

  19. Analysis of the thermal response of plasma facing components during a runaway electron impact

    NASA Astrophysics Data System (ADS)

    Ward, Robert Cameron

    The generation of runaway electrons during a thermal plasma disruption is a concern for the safe and economical operation of a tokamak power system. Runaway electrons have high energy, 10--300 MeV, and may potentially cause extensive damage to plasma facing components through large temperature increases, melting of metallic components, surface erosion, and possible burnout of coolant tubes. The EPQ code system was developed to simulate the thermal response of plasma facing components to a runaway electron impact. The EPQ code system consists of several parts: UNIX scripts which control the operation of an electron-photon monte carlo code to calculate the interaction of the runaway electrons with the plasma facing materials; a finite difference code to calculate the thermal response, melting, and surface erosion of the materials using the modified heat conduction equation; a code to process, scale, transform, and convert the electron monte carlo data to volumetric heating rates for use in the thermal code; and several minor and auxiliary codes for the manipulation and post-processing of the data. The electron-photon monte carlo code used was the Electron-Gamma-Shower (EGS) code, developed and maintained by the National Research Center of Canada. The other codes were written in C++ for this study. The thermal code, called QTTN, solves the two-dimensional cylindrical modified heat conduction equation using the Quickest third-order accurate and stable explicit finite difference method and is capable of tracking melting or surface erosion. The EPQ code system was validated using a series of analytical solutions and simulations of experiments. QTTN and EPQ was verified and validated as able to calculate the temperature distribution, phase change, and surface erosion successfully. EPQ was then employed in a parametric study to simulate a typical runaway electron disruption impact on the FIRE design's plasma facing components. The results of the FIRE parametric study

  20. 78 FR 71643 - Certain Wireless Consumer Electronics Devices and Components Thereof; Commission Determination To...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-29

    ... (collectively ``Complainants''). 77 FR 51572-573 (August 24, 2012). The complaint alleges violations of section... 21, 2005, 70 FR 43251 (July 26, 2005). During this period, the subject articles would be entitled to... COMMISSION Certain Wireless Consumer Electronics Devices and Components Thereof; Commission Determination...

  1. 76 FR 55944 - In the Matter of Certain Electronic Devices With Image Processing Systems, Components Thereof...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-09

    ... filed by S3 Graphics Co. Ltd. and S3 Graphics Inc. (collectively, ``S3G''). 75 FR 38118 (July 1, 2010... 21, 2005, 70 FR 43251 (July 26, 2005). During this period, the subject articles would be entitled to... COMMISSION In the Matter of Certain Electronic Devices With Image Processing Systems, Components Thereof,...

  2. 76 FR 60870 - In the Matter of Certain Electronic Devices With Communication Capabilities, Components Thereof...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-30

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION In the Matter of Certain Electronic Devices With Communication Capabilities, Components Thereof... 19 U.S.C. 1337 AGENCY: U.S. International Trade Commission. ACTION: Notice. SUMMARY: Notice is...

  3. Formal estimation of the random component in global maps of total electron content

    NASA Astrophysics Data System (ADS)

    Choliy, V. Ya.

    2016-09-01

    Random component of the total electron content (TEC) maps, produced by global navigation satellite system processing centres, was analysed. Helmert transform (HT) and two-dimension singular spectrum analysis (2dSSA) were used. Optimal parameters (in the sense calculation speed versus quality) of the 2dSSA windows were determined along with precision estimations.

  4. 75 FR 28651 - In the Matter of Certain Electronic Paper Towel Dispensing Devices and Components Thereof; Notice...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-21

    ... COMMISSION In the Matter of Certain Electronic Paper Towel Dispensing Devices and Components Thereof; Notice... the sale within the United States after importation of certain electronic paper towel dispensing... electronic paper towel dispensing devices or components thereof that infringe one or more of claims 1-7 of...

  5. Interpretation of analysis of variance models using principal component analysis to assess the effect of a maternal anticancer treatment on the mineralization of rat bones.

    PubMed

    Stanimirova, I; Michalik, K; Drzazga, Z; Trzeciak, H; Wentzell, P D; Walczak, B

    2011-03-01

    The goal of the present study is to assess the effects of anticancer treatment with cyclophosphamide and cytarabine during pregnancy on the mineralization of mandible bones in 7-, 14- and 28-day-old rats. Each bone sample was described by its X-ray fluorescence spectrum characterizing the mineral composition. The data collected are multivariate in nature and their structure is difficult to visualize and interpret directly. Therefore, methods like analysis of variance-principal component analysis (ANOVA-PCA) and ANOVA-simultaneous component analysis (ASCA), which are suitable for the analysis of highly correlated spectral data and are able to incorporate information about the underlined experimental design, are greatly valued. In this study, the ASCA methodology adapted for unbalanced data was used to investigate the impact of the anticancer drug treatment during pregnancy on the mineralization of the mandible bones of newborn rats and to examine any changes in the mineralization of the bones over time. The results showed that treatment with cyclophosphamide and cytarabine during pregnancy induces a decrease in the K and Zn levels in the mandible bones of newborns. This suppresses the development of mandible bones in rats in the early stages (up to 14 days) of formation. An interesting observation was that the levels of essential minerals like K, Mg, Na and Ca vary considerably in the different regions of the mandible bones.

  6. The Use of Backscattered Electron Imaging and Transmission Electron Microscopy to Assess Bone Architecture and Mineral Loci: Effect of Intermittent Slow-Release Sodium Fluoride Therapy

    NASA Astrophysics Data System (ADS)

    Zerwekh, Joseph E.; Bellotto, Dennis; Prostak, Kenneth S.; Hagler, Herbert K.; Pak, Charles Y. C.

    1996-04-01

    Backscattered electron imaging (BEI) and transmission electron microscopy (TEM) were used to examine the effects of treatment with intermittent slow-release sodium fluoride (SRNaF) and continuous calcium citrate on bone architecture and crystallinity. Examination was performed in nondecalcified biopsies obtained from patients following up to four years of therapy (placebo or SRNaF) and compared to pretreatment biopsies from each patient, as well as to bone from young, normal subjects. BEI images disclosed increased areas of recent bone formation following fluoride administration. There was no evidence of a mineralization defect in any biopsy and both cortical and trabecular architecture remained normal. TEM analysis demonstrated intrafibrillar platelike crystals and extrafibrillar needlelike crystals for both the pre- and post-treatment biopsies as well as for the bone from young normal subjects. There was no evidence of increased crystal size or of an increase in extrafibrillar mineral deposition. These observations suggest that intermittent SRNaF and continuous calcium therapy exerts an anabolic action on the skeleton not accompanied by a mineralization defect or an alteration of bone mineral deposition. The use of BEI and TEM holds promise for the study of the pathophysiology and treatment of metabolic bone diseases.

  7. Thermoelectricity Generation and Electron-Magnon Scattering in a Natural Chalcopyrite Mineral from a Deep-Sea Hydrothermal Vent.

    PubMed

    Ang, Ran; Khan, Atta Ullah; Tsujii, Naohito; Takai, Ken; Nakamura, Ryuhei; Mori, Takao

    2015-10-26

    Current high-performance thermoelectric materials require elaborate doping and synthesis procedures, particularly in regard to the artificial structure, and the underlying thermoelectric mechanisms are still poorly understood. Here, we report that a natural chalcopyrite mineral, Cu1+x Fe1-x S2 , obtained from a deep-sea hydrothermal vent can directly generate thermoelectricity. The resistivity displayed an excellent semiconducting character, and a large thermoelectric power and high power factor were found in the low x region. Notably, electron-magnon scattering and a large effective mass was detected in this region, thus suggesting that the strong coupling of doped carriers and antiferromagnetic spins resulted in the natural enhancement of thermoelectric properties during mineralization reactions. The present findings demonstrate the feasibility of thermoelectric energy generation and electron/hole carrier modulation with natural materials that are abundant in the Earth's crust.

  8. Thermoelectricity Generation and Electron-Magnon Scattering in a Natural Chalcopyrite Mineral from a Deep-Sea Hydrothermal Vent.

    PubMed

    Ang, Ran; Khan, Atta Ullah; Tsujii, Naohito; Takai, Ken; Nakamura, Ryuhei; Mori, Takao

    2015-10-26

    Current high-performance thermoelectric materials require elaborate doping and synthesis procedures, particularly in regard to the artificial structure, and the underlying thermoelectric mechanisms are still poorly understood. Here, we report that a natural chalcopyrite mineral, Cu1+x Fe1-x S2 , obtained from a deep-sea hydrothermal vent can directly generate thermoelectricity. The resistivity displayed an excellent semiconducting character, and a large thermoelectric power and high power factor were found in the low x region. Notably, electron-magnon scattering and a large effective mass was detected in this region, thus suggesting that the strong coupling of doped carriers and antiferromagnetic spins resulted in the natural enhancement of thermoelectric properties during mineralization reactions. The present findings demonstrate the feasibility of thermoelectric energy generation and electron/hole carrier modulation with natural materials that are abundant in the Earth's crust. PMID:26332260

  9. Redox properties of structural Fe in clay minerals. 1. Electrochemical quantification of electron-donating and -accepting capacities of smectites.

    PubMed

    Gorski, Christopher A; Aeschbacher, Michael; Soltermann, Daniela; Voegelin, Andreas; Baeyens, Bart; Marques Fernandes, Maria; Hofstetter, Thomas B; Sander, Michael

    2012-09-01

    Clay minerals often contain redox-active structural iron that participates in electron transfer reactions with environmental pollutants, bacteria, and biological nutrients. Measuring the redox properties of structural Fe in clay minerals using electrochemical approaches, however, has proven to be difficult due to a lack of reactivity between clay minerals and electrodes. Here, we overcome this limitation by using one-electron-transfer mediating compounds to facilitate electron transfer between structural Fe in clay minerals and a vitreous carbon working electrode in an electrochemical cell. Using this approach, the electron-accepting and -donating capacities (Q(EAC) and Q(EDC)) were quantified at applied potentials (E(H)) of -0.60 V and +0.61 V (vs SHE), respectively, for four natural Fe-bearing smectites (i.e., SWa-1, SWy-2, NAu-1, and NAu-2) having different total Fe contents (Fe(total) = 2.3 to 21.2 wt % Fe) and varied initial Fe(2+)/Fe(total) states. For every SWa-1 and SWy-2 sample, all the structural Fe was redox-active over the tested E(H) range, demonstrating reliable quantification of Fe content and redox state. Yet for NAu-1 and NAu-2, a significant fraction of the structural Fe was redox-inactive, which was attributed to Fe-rich smectites requiring more extreme E(H)-values to achieve complete Fe reduction and/or oxidation. The Q(EAC) and Q(EDC) values provided here can be used as benchmarks in future studies examining the extent of reduction and oxidation of Fe-bearing smectites.

  10. Mid-Infrared Spectroscopy Analysis of the Effects of Erbium, Chromium:Yattrium-Scandium-Gallium-Garnet (Er,Cr:YSGG) Laser Irradiation on Bone Mineral and Organic Components.

    PubMed

    Benetti, Carolina; Ana, Patricia Aparecida; Bachmann, Luciano; Zezell, Denise Maria

    2015-12-01

    The effects of varying the energy density of a high-intensity erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser on the mineral and organic components of bone tissue were evaluated using Fourier transform infrared spectroscopy. Bone samples obtained from the tibias of rabbits were irradiated with five energy densities (3, 6, 8, 12, and 15 J/cm(2)), and the effects on the carbonate to phosphate ratio and in the organic components were compared with those of nonirradiated samples. The increased temperature during the laser irradiation was also measured using infrared thermography to relate the observed spectral changes to the laser thermal effects. The analyses of the infrared spectra suggests that the irradiation with Er,Cr:YSGG promoted changes in bone tissue in both the mineral and organic components that depend on the laser energy density, pointing to the importance of using the proper energy density in clinical procedures.

  11. Mid-Infrared Spectroscopy Analysis of the Effects of Erbium, Chromium:Yattrium-Scandium-Gallium-Garnet (Er,Cr:YSGG) Laser Irradiation on Bone Mineral and Organic Components.

    PubMed

    Benetti, Carolina; Ana, Patricia Aparecida; Bachmann, Luciano; Zezell, Denise Maria

    2015-12-01

    The effects of varying the energy density of a high-intensity erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser on the mineral and organic components of bone tissue were evaluated using Fourier transform infrared spectroscopy. Bone samples obtained from the tibias of rabbits were irradiated with five energy densities (3, 6, 8, 12, and 15 J/cm(2)), and the effects on the carbonate to phosphate ratio and in the organic components were compared with those of nonirradiated samples. The increased temperature during the laser irradiation was also measured using infrared thermography to relate the observed spectral changes to the laser thermal effects. The analyses of the infrared spectra suggests that the irradiation with Er,Cr:YSGG promoted changes in bone tissue in both the mineral and organic components that depend on the laser energy density, pointing to the importance of using the proper energy density in clinical procedures. PMID:26555304

  12. A review of current and future components for electronic warfare receivers

    NASA Astrophysics Data System (ADS)

    Collins, J. H.; Grant, P. M.

    1981-05-01

    This paper addresses the role of conventional and new components in passive electronic warfare (EW) receivers. The various areas of EW are defined before restricting the discussion predominantly to the radar intercept problem at microwave frequencies. The operational parameters of conventional components are then reviewed including the multiplexer; crystal video, instantaneous frequency measurement (IFM), and scanning superheterodyne receivers. The significance of modularity, digital control, and hybrid combinations of components is highlighted. A brief description follows of the operational Cutlass EW equipment. New components based on surface-acoustic waves (SAW) and acoustooptic (AO) Bragg cells are then presented and their particular importance in channelized receivers, IFM's, and microscan receivers noted. Finally, a number of conclusions are drawn covering likely trends in EW receivers and the need for continuing development of large-scale integrated (LSI) circuits for signal sorting and overall digital management.

  13. Graphene radio frequency and microwave passive components for low cost wearable electronics

    NASA Astrophysics Data System (ADS)

    Huang, Xianjun; Leng, Ting; Hsin Chang, Kuo; Cing Chen, Jia; Novoselov, Kostya S.; Hu, Zhirun

    2016-06-01

    Graphene RF and microwave passive components such as coplanar waveguide transmission lines, open/short-circuited resonators and wideband antenna on paper substrate were designed, screen printed and characterized in this work. The experimental results demonstrate that the screen printed graphene passive components can be used for RF signal transmitting, processing and radiating/receiving; revealing that graphene ink can be a low cost alternative to much more expensive metal nanoparticle inks, such as silver nanoparticle ink. The screen printed graphene is processed at low temperature so that it is compatible with heat-sensitive flexible materials like papers, PTFE (Polytetrafluoroethylene) and textiles. The screen printed graphene passive components reported here are of high conductivity, high flexibility, light weight and low cost, making them ideal candidate for low cost wearable electronics. This work makes it prospective to manufacture RF and microwave passive components in mass production by screen printing in much lower cost to any other known techniques.

  14. Approach to In Situ Component Level Electronics Assembly Repair (CLEAR) for Constellation

    NASA Technical Reports Server (NTRS)

    Struk, Peter M.; Oeftering, Richard C.

    2010-01-01

    Maintenance resupply is a significant issue for long duration space missions. Currently, the International Space Station (ISS) approaches maintenance primarily around replaceable modules called Orbital Replacement Units (ORU). While swapping out ORUs has served the ISS well keeping crew time for maintenance to a minimum, this approach assumes a substantial logistics capacity to provide replacement ORUs and return ORUs to Earth for repair. The ORUs used for ISS require relatively large blocks of replacement hardware even though the actual failed component may be several orders of magnitude smaller. The Component Level Electronics Assembly Repair (CLEAR) task was created to explore electronics repair down to the component level for future space missions. From 2006 to 2009, CLEAR was an activity under the Supportability project of the Exploration Technology Development Program. This paper describes the activities of CLEAR including making a case for component-level electronics repair, examination of current terrestrial repair hardware, and potential repair needs. Based on those needs, the CLEAR team proposes an architecture for an in-situ repair capability aboard a spacecraft or habitat. Additionally, this paper discusses recent progress toward developing in-space repair capabilities--including two spaceflight experiments-- and presents technology concepts which could help enable or benefit the same.

  15. Sequential energy and electron transfer in a three-component system aligned on a clay nanosheet.

    PubMed

    Fujimura, Takuya; Ramasamy, Elamparuthi; Ishida, Yohei; Shimada, Tetsuya; Takagi, Shinsuke; Ramamurthy, Vaidhyanathan

    2016-02-21

    To achieve the goal of energy transfer and subsequent electron transfer across three molecules, a phenomenon often utilized in artificial light harvesting systems, we have assembled a light absorber (that also serves as an energy donor), an energy acceptor (that also serves as an electron donor) and an electron acceptor on the surface of an anionic clay nanosheet. Since neutral organic molecules have no tendency to adsorb onto the anionic surface of clay, a positively charged water-soluble organic capsule was used to hold neutral light absorbers on the above surface. A three-component assembly was prepared by the co-adsorption of a cationic bipyridinium derivative, cationic zinc porphyrin and cationic octaamine encapsulated 2-acetylanthracene on an exfoliated anionic clay surface in water. Energy and electron transfer phenomena were monitored by steady state fluorescence and picosecond time resolved fluorescence decay. The excitation of 2-acetylanthracene in the three-component system resulted in energy transfer from 2-acetylanthracene to zinc porphyrin with 71% efficiency. Very little loss due to electron transfer from 2-acetylanthracene in the cavitand to the bipyridinium derivative was noticed. Energy transfer was followed by electron transfer from the zinc porphyrin to the cationic bipyridinium derivative with 81% efficiency. Analyses of fluorescence decay profiles confirmed the occurrence of energy transfer and subsequent electron transfer. Merging the concepts of supramolecular chemistry and surface chemistry we realized sequential energy and electron transfer between three hydrophobic molecules in water. Exfoliated transparent saponite clay served as a matrix to align the three photoactive molecules at a close distance in aqueous solutions. PMID:26820105

  16. A New Approach to Provide Reliable Data Systems Without Using Space-Qualified Electronic Components

    NASA Astrophysics Data System (ADS)

    Häbel, W.

    This paper describes the present situation and the expected trends with regard to the availability of electronic components, their quality levels, technology trends and sensitivity to the space environment. Many recognized vendors have already discontinued their MIL production line and state of the art components will in many cases not be offered in this quality level because of the shrinking market. It becomes therefore obvious that new methods need to be considered "How to build reliable Data Systems for space applications without High-Rel parts". One of the most promising approaches is the identification, masking and suppression of faults by developing Fault Tolerant Computer systems which is described in this paper.

  17. Influence of humic substances on Co[sup 2+] sorption by a subsurface mineral separate and its mineralogic components

    SciTech Connect

    Zachara, J.M.; Resch, C.T.; Smith, S.C. )

    1994-01-01

    The sorption of Co[sup 2+] (10[sup [minus]6] mol/L) was measured on subsurface mineral materials in the absence and presence of a sorbed leonardite humic acid (LHA) to (1) evaluate the sorptive role of mineral-bound humic substances, and (2) establish approaches to model metal ion binding in composite materials. The subsurface materials were a <2.0 [mu]m size fraction of an ultisol saprolite (CP) and this same material treated with dithonite-citrate-bicarbonate (DCB) to remove Fe-oxides (DCP). Comparable experiments (with and without LHA) were also performed with mineral sorbents representing dominant phases in the CP separate (gibbsite, Al-geothite, and kalonite) to evaluate their potential contributions to Co sorption. The mineral-bound LHA ranged in concentration between 0.1-0.4 mg-C/m[sup 2], representing approximately 0.7% of the subsurface isolate by mass. In solid-free suspensions, the affinity of LHA for Co increased with pH and decreasing I (K[sub d] ranging 20-450 L/g). Mineral-bound LHA increased Co sorption on all the sorbents by factors of 10-60%, with the greatest augmentation noted at pH values (4.5-6.5) where (1) maximum LHA sorption occurred, and (2) Co sorption to the mineral phase was weak and dominated by ion exchange. The LHA appeared simply to augment, rather than to change the intrinsic adsorption behavior of the mineral sorbents. Accordingly, predictions of the K[sub d] for Co on the LHA-coated subsurface materials (DCP, CP) based on a linear additivity model agreed well with the experimental data, suggesting that the complex humic-mineral association acted as a noninterative sorbent mixture at low aqueous Co concentrations.

  18. Radiation and temperature effects on electronic components investigated under the CSTI high capacity power project

    NASA Astrophysics Data System (ADS)

    Schwarze, Gene E.; Niedra, Janis M.; Frasca, Albert J.; Wieserman, William R.

    1993-01-01

    The effects of nuclear radiation and high temperature environments must be fully known and understood for the electronic components and materials used in both the Power Conditioning and Control subsystem and the reactor Instrumentation and Control subsystem of future high capacity nuclear space power systems. This knowledge is required by the designer of these subsystems in order to develop highly reliable, long-life power systems for future NASA missions. A review and summary of the experimental results obtained for the electronic components and materials investigated under the power management element of the CSTI high capacity power project will be presented in this paper: (1) Neutron, gamma ray, and temperature effects on power semiconductor switches, (2) Temperature and frequency effects on soft magnetic materials; and (3) Temperature effects on rare-earth permanent magnets.

  19. Radiation and temperature effects on electronic components investigated under the CSTI high capacity power project

    NASA Technical Reports Server (NTRS)

    Schwarze, Gene E.; Niedra, Janis M.; Frasca, Albert J.; Wieserman, William R.

    1993-01-01

    The effects of nuclear radiation and high temperature environments must be fully known and understood for the electronic components and materials used in both the Power Conditioning and Control subsystem and the reactor Instrumentation and Control subsystem of future high capacity nuclear space power systems. This knowledge is required by the designer of these subsystems in order to develop highly reliable, long-life power systems for future NASA missions. A review and summary of the experimental results obtained for the electronic components and materials investigated under the power management element of the Civilian Space Technology Initiative (CSTI) high capacity power project are presented: (1) neutron, gamma ray, and temperature effects on power semiconductor switches, (2) temperature and frequency effects on soft magnetic materials; and (3) temperature effects on rare earth permanent magnets.

  20. DEVELOPMENT OF MULTI-PHASE AND MULTI-COMPONENT FLOW MODEL WITH REACTION IN POROUS MEDIA FOR RISK ASSESSMENT ON SOIL CONTAMINATION DUE TO MINERAL OIL

    NASA Astrophysics Data System (ADS)

    Sakamoto, Yasuhide; Nishiwaki, Junko; Hara, Junko; Kawabe, Yoshishige; Sugai, Yuichi; Komai, Takeshi

    In late years, soil contamination due to mineral oil in vacant lots of oil factory and oil field has become obvious. Measure for soil contamina tion and risk assessment are neces sary for sustainable development of industrial activity. Especially, in addition to contaminated sites, various exposure paths for human body such as well water, soil and farm crop are supposed. So it is very important to comprehend the transport phenomena of contaminated material under the environments of soil and ground water. In this study, mineral oil as c ontaminated material consisting of mu lti-component such as aliphatic and aromatic series was modeled. Then numerical mode l for transport phenomena in surface soil and aquifer was constructed. On the basis of modeling for mineral oil, our numerical model consists of three-phase (oil, water and gas) forty three-component. This numerical model becomes base program for risk assessment system on soil contamination due to mineral oil. Using this numerical model, we carried out some numerical simulation for a laboratory-scale experiment on oil-water multi-phase flow. Relative permeability that dominate flow behavior in multi-phase condition was formulated and the validity of the numerical model developed in this study was considered.

  1. Changes in the mineral density distribution in human bone with age: image analysis using backscattered electrons in the SEM.

    PubMed

    Reid, S A; Boyde, A

    1987-02-01

    We report a study to test the feasibility of studying mineral density distributions in bone using the backscattered electron signal in scanning electron microscopy. Samples were human sixth ribs ranging in age from 8 weeks to 59 years, embedded in polymethylmethacrylate (PMMA), cut, polished, and carbon coated. The proportions of pixels falling in a uniform set of gray level slices of the BSE signal were determined using a microcomputer-based image analysis system interfaced directly to the SEM. The amount of high-density bone gradually increased with age at the expense of low-density bone, and there was an associated compression of the range of the mineral density distribution. Age-related differences were noted between the density distributions in the outer and inner rib cortices. The distribution in the inner cortex in neonates was influenced by the inclusion of densely mineralized endochondral bone and cartilage trabeculae formed at the growth cartilage zone. In adults it appeared that greater bone turnover occurred in the outer cortex, perhaps reflecting a differential mechanical loading across the rib. The technique enabled rapid, unbiased discrimination between the bone of neonates, children, and adults. PMID:3455153

  2. The nanometre-scale physiology of bone: steric modelling and scanning transmission electron microscopy of collagen-mineral structure.

    PubMed

    Alexander, Benjamin; Daulton, Tyrone L; Genin, Guy M; Lipner, Justin; Pasteris, Jill D; Wopenka, Brigitte; Thomopoulos, Stavros

    2012-08-01

    The nanometre-scale structure of collagen and bioapatite within bone establishes bone's physical properties, including strength and toughness. However, the nanostructural organization within bone is not well known and is debated. Widely accepted models hypothesize that apatite mineral ('bioapatite') is present predominantly inside collagen fibrils: in 'gap channels' between abutting collagen molecules, and in 'intermolecular spaces' between adjacent collagen molecules. However, recent studies report evidence of substantial extrafibrillar bioapatite, challenging this hypothesis. We studied the nanostructure of bioapatite and collagen in mouse bones by scanning transmission electron microscopy (STEM) using electron energy loss spectroscopy and high-angle annular dark-field imaging. Additionally, we developed a steric model to estimate the packing density of bioapatite within gap channels. Our steric model and STEM results constrain the fraction of total bioapatite in bone that is distributed within fibrils at less than or equal to 0.42 inside gap channels and less than or equal to 0.28 inside intermolecular overlap regions. Therefore, a significant fraction of bone's bioapatite (greater than or equal to 0.3) must be external to the fibrils. Furthermore, we observe extrafibrillar bioapatite between non-mineralized collagen fibrils, suggesting that initial bioapatite nucleation and growth are not confined to the gap channels as hypothesized in some models. These results have important implications for the mechanics of partially mineralized and developing tissues.

  3. Recommendations for Enabling Manual Component Level Electronic Repair for Future Space Missions

    NASA Technical Reports Server (NTRS)

    Struk, Peter M.; Easton, John W.; Funk, Gregory P.; Latta, Gary S.; Ganster, Andrew W.; Estes, Brett E.

    2011-01-01

    Long duration missions to the Moon and Mars pose a number of challenges to mission designers, controllers, and the crews. Among these challenges are planning for corrective maintenance actions which often require a repair. Current repair strategies on the International Space Station (ISS) rely primarily on the use of Orbital Replacement Units (ORUs), where a faulty unit is replaced with a spare, and the faulty unit typically returns to Earth for analysis and possible repair. The strategy of replace to repair has posed challenges even for the ISS program. Repairing faulty hardware at lower levels such as the component level can help maintain system availability in situations where no spares exist and potentially reduce logistic resupply mass.This report provides recommendations to help enable manual replacement of electronics at the component-level for future manned space missions. The recommendations include hardware, tools, containment options, and crew training. The recommendations are based on the work of the Component Level Electronics Assembly Repair (CLEAR) task of the Exploration Technology Development Program from 2006 to 2009. The recommendations are derived based on the experience of two experiments conducted by the CLEAR team aboard the International Space Station as well as a group of experienced Miniature/Microminiature (2M) electronics repair technicians and instructors from the U.S. Navy 2M Project Office. The emphasis of the recommendations is the physical repair. Fault diagnostics and post-repair functional test are discussed in other CLEAR reports.

  4. A model for computing vibration induced stresses of electronic components in a general flexible mounting

    NASA Astrophysics Data System (ADS)

    Silva, Gustavo H. C.; Paupitz Gonçalves, Paulo J.

    2013-09-01

    This paper develops a novel full analytic model for vibration analysis of solid-state electronic components. The model is just as accurate as finite element models and numerically light enough to permit for quick design trade-offs and statistical analysis. The paper shows the development of the model, comparison to finite elements and an application to a common engineering problem. A gull-wing flat pack component was selected as the benchmark test case, although the presented methodology is applicable to a wide range of component packages. Results showed very good agreement between the presented method and finite elements and demonstrated the usefulness of the method in how to use standard test data for a general application. The properties E, G, A, I, J and κ need not be constants; they may all be functions of s.

  5. Transmission Electron Microscopy of the Matrix Minerals in the Tagish Lake Carbonaceous Chondrite

    NASA Technical Reports Server (NTRS)

    Mikouchi, T.; Kasama, T.; Zolensky, M. E.; Tachikawa, O.

    2001-01-01

    We studied the Tagish Lake matrix minerals by TEM. The result shows similarities to CIs (and CRs) and differences from CMs, but its heterogeneity (e.g., carbonate abundance, saponite/serpentine ratio) suggests its complex history. Additional information is contained in the original extended abstract.

  6. Modeling dust as component minerals in the Community Atmosphere Model: development of framework and impact on radiative forcing

    DOE PAGES

    Scanza, R. A.; Mahowald, N.; Ghan, S.; Zender, C. S.; Kok, J. F.; Liu, X.; Zhang, Y.; Albani, S.

    2015-01-15

    The mineralogy of desert dust is important due to its effect on radiation, clouds and biogeochemical cycling of trace nutrients. This study presents the simulation of dust radiative forcing as a function of both mineral composition and size at the global scale, using mineral soil maps for estimating emissions. Externally mixed mineral aerosols in the bulk aerosol module in the Community Atmosphere Model version 4 (CAM4) and internally mixed mineral aerosols in the modal aerosol module in the Community Atmosphere Model version 5.1 (CAM5) embedded in the Community Earth System Model version 1.0.5 (CESM) are speciated into common mineral componentsmore » in place of total dust. The simulations with mineralogy are compared to available observations of mineral atmospheric distribution and deposition along with observations of clear-sky radiative forcing efficiency. Based on these simulations, we estimate the all-sky direct radiative forcing at the top of the atmosphere as + 0.05 Wm−2 for both CAM4 and CAM5 simulations with mineralogy. We compare this to the radiative forcing from simulations of dust in release versions of CAM4 and CAM5 (+0.08 and +0.17 Wm−2) and of dust with optimized optical properties, wet scavenging and particle size distribution in CAM4 and CAM5, −0.05 and −0.17 Wm−2, respectively. The ability to correctly include the mineralogy of dust in climate models is hindered by its spatial and temporal variability as well as insufficient global in situ observations, incomplete and uncertain source mineralogies and the uncertainties associated with data retrieved from remote sensing methods.« less

  7. Modeling dust as component minerals in the Community Atmosphere Model: development of framework and impact on radiative forcing

    DOE PAGES

    Scanza, R. A.; Mahowald, N.; Ghan, S.; Zender, C. S.; Kok, J. F.; Liu, X.; Zhang, Y.

    2014-07-02

    The mineralogy of desert dust is important due to its effect on radiation, clouds and biogeochemical cycling of trace nutrients. This study presents the simulation of dust radiative forcing as a function of both mineral composition and size at the global scale using mineral soil maps for estimating emissions. Externally mixed mineral aerosols in the bulk aerosol module in the Community Atmosphere Model version 4 (CAM4) and internally mixed mineral aerosols in the modal aerosol module in the Community Atmosphere Model version 5.1 (CAM5) embedded in the Community Earth System Model version 1.0.5 (CESM) are speciated into common mineral componentsmore » in place of total dust. The simulations with mineralogy are compared to available observations of mineral atmospheric distribution and deposition along with observations of clear-sky radiative forcing efficiency. Based on these simulations, we estimate the all-sky direct radiative forcing at the top of the atmosphere as +0.05 W m−2 for both CAM4 and CAM5 simulations with mineralogy and compare this both with simulations of dust in release versions of CAM4 and CAM5 (+0.08 and +0.17 W m−2) and of dust with optimized optical properties, wet scavenging and particle size distribution in CAM4 and CAM5, −0.05 and −0.17 W m−2, respectively. The ability to correctly include the mineralogy of dust in climate models is hindered by its spatial and temporal variability as well as insufficient global in-situ observations, incomplete and uncertain source mineralogies and the uncertainties associated with data retrieved from remote sensing methods.« less

  8. 76 FR 32373 - In the Matter of Certain Electronic Devices Having a Digital Television Receiver and Components...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-06

    ... COMMISSION In the Matter of Certain Electronic Devices Having a Digital Television Receiver and Components... electronic devices having a digital television receiver and components thereof that infringe one or more of... sale for importation, and the sale within the United States after importation of certain...

  9. 78 FR 75336 - Notice of Intent To Grant an Exclusive License; Aviation Devices and Electronic Components, L.L.C.

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-11

    ... Department of Navy Notice of Intent To Grant an Exclusive License; Aviation Devices and Electronic Components... hereby gives notice of its intent to grant to Aviation Devices and Electronic Components, L.L.C. located.... ADDRESSES: Written objections are to be filed with the Naval Air Warfare Center Aircraft...

  10. Evaluation of Power Electronic Components and Systems at Cryogenic Temperatures For Space Missions

    NASA Technical Reports Server (NTRS)

    Elbuluk, Malik E.; Gerber, Scott; Hammoud, Ahmad; Patterson, Richard L.

    2005-01-01

    Power electronic circuits and systems designed for deep space applications and outer planetary exploration are required to operate reliably and efficiently under extreme temperature conditions. This requirement is dictated by the fact that the operational environments associated with some of the space missions would encompass temperatures as low as -183 C. The development and utilization of electronics capable of low temperature operation would not only fulfill the advanced technology requirements, but also would contribute to improving circuit performance, increasing system efficiency, and reducing development and launch costs. These benefits are generally achieved by the improved intrinsic properties of some of the electronic materials at low temperature, reduced device losses, and the elimination of heating elements used in conventional systems at low temperatures. Power electronic circuits are widely used in space power systems in the areas of power management, conditioning, and control. In this work, the performance of certain power electronic components and systems was investigated under low temperature. These include inductors, capacitors, pulse-width-modulation (PWM) controllers, and advanced commercial DC/DC converter modules. Different properties were determined as a function of temperature in the range of 20 C to -140 C, at various current and voltages levels. The experimental procedures along with the experimental data obtained are presented and discussed in this paper.

  11. Hexavalent chromium reduction by Cellulomonas sp. strain ES6: the influence of carbon source, iron minerals, and electron shuttling compounds.

    PubMed

    Field, Erin K; Gerlach, Robin; Viamajala, Sridhar; Jennings, Laura K; Peyton, Brent M; Apel, William A

    2013-06-01

    The reduction of hexavalent chromium, Cr(VI), to trivalent chromium, Cr(III), can be an important aspect of remediation processes at contaminated sites. Cellulomonas species are found at several Cr(VI) contaminated and uncontaminated locations at the Department of Energy site in Hanford, Washington. Members of this genus have demonstrated the ability to effectively reduce Cr(VI) to Cr(III) fermentatively and therefore play a potential role in Cr(VI) remediation at this site. Batch studies were conducted with Cellulomonas sp. strain ES6 to assess the influence of various carbon sources, iron minerals, and electron shuttling compounds on Cr(VI) reduction rates as these chemical species are likely to be present in, or added to, the environment during in situ bioremediation. Results indicated that the type of carbon source as well as the type of electron shuttle present influenced Cr(VI) reduction rates. Molasses stimulated Cr(VI) reduction more effectively than pure sucrose, presumably due to presence of more easily utilizable sugars, electron shuttling compounds or compounds with direct Cr(VI) reduction capabilities. Cr(VI) reduction rates increased with increasing concentration of anthraquinone-2,6-disulfonate (AQDS) regardless of the carbon source. The presence of iron minerals and their concentrations did not significantly influence Cr(VI) reduction rates. However, strain ES6 or AQDS could directly reduce surface-associated Fe(III) to Fe(II), which was capable of reducing Cr(VI) at a near instantaneous rate. These results suggest the rate limiting step in these systems was the transfer of electrons from strain ES6 to the intermediate or terminal electron acceptor whether that was Cr(VI), Fe(III), or AQDS.

  12. Vibrational Analysis of Engine Components Using Neural-Net Processing and Electronic Holography

    NASA Technical Reports Server (NTRS)

    Decker, Arthur J.; Fite, E. Brian; Mehmed, Oral; Thorp, Scott A.

    1998-01-01

    The use of computational-model trained artificial neural networks to acquire damage specific information from electronic holograms is discussed. A neural network is trained to transform two time-average holograms into a pattern related to the bending-induced-strain distribution of the vibrating component. The bending distribution is very sensitive to component damage unlike the characteristic fringe pattern or the displacement amplitude distribution. The neural network processor is fast for real-time visualization of damage. The two-hologram limit makes the processor more robust to speckle pattern decorrelation. Undamaged and cracked cantilever plates serve as effective objects for testing the combination of electronic holography and neural-net processing. The requirements are discussed for using finite-element-model trained neural networks for field inspections of engine components. The paper specifically discusses neural-network fringe pattern analysis in the presence of the laser speckle effect and the performances of two limiting cases of the neural-net architecture.

  13. Vibrational Analysis of Engine Components Using Neural-Net Processing and Electronic Holography

    NASA Technical Reports Server (NTRS)

    Decker, Arthur J.; Fite, E. Brian; Mehmed, Oral; Thorp, Scott A.

    1997-01-01

    The use of computational-model trained artificial neural networks to acquire damage specific information from electronic holograms is discussed. A neural network is trained to transform two time-average holograms into a pattern related to the bending-induced-strain distribution of the vibrating component. The bending distribution is very sensitive to component damage unlike the characteristic fringe pattern or the displacement amplitude distribution. The neural network processor is fast for real-time visualization of damage. The two-hologram limit makes the processor more robust to speckle pattern decorrelation. Undamaged and cracked cantilever plates serve as effective objects for testing the combination of electronic holography and neural-net processing. The requirements are discussed for using finite-element-model trained neural networks for field inspections of engine components. The paper specifically discusses neural-network fringe pattern analysis in the presence of the laser speckle effect and the performances of two limiting cases of the neural-net architecture.

  14. Assessment of Selected CERES Electronic Component Survivability under Simulated Overvoltage Conditions

    NASA Technical Reports Server (NTRS)

    Chapman, John J.; Grant, M. S.; Bockman, J.; Clark, V. M.; Hess, P. C.

    1999-01-01

    In August, 1998 a Clouds and the Earth's Radiant Energy System (CERES) instrument telemetry housekeeping parameter generated a yellow warning message that indicated an on-board + 15V Data Acquisition Assembly (DAA) power converter deregulation anomaly. An exhaustive investigation was undertaken to understand this anomaly and the long-term consequences which have severely reduced CERES operations on the Tropical Rainfall Measuring Mission (TRMM) spacecraft. Among investigations performed were ground tests that approximated the on-board electronic circuitry using a small quantity of flight identical components exposed to maximum spacecraft bus over-voltage conditions. These components include monolithic integrated microcircuits that perform analog signal conditioning on instrument sensor signals and an analog- to-digital converter (ADC) for the entire DAA. All microcircuit packages have either a bipolar silicon design with internal current limiting protections or have a complementary metal oxide semiconductor (CMOS) design with bias protections. Ground tests that have been running for approximately 8 months have indicated that these components are capable of withstanding as much as twice their input supply voltage ratings without noticeable performance degradation. These data provide CERES operators with confidence of being able to continue science operations over the remaining life of the TRMM mission. This paper will discuss this anomaly and some possible causes, a simulator of affected electronics, test results, prognosis for future CERES operations, and conclusions.

  15. 76 FR 54496 - In the Matter of Certain Electronic Devices Having a Digital Television Receiver and Components...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-01

    ... COMMISSION In the Matter of Certain Electronic Devices Having a Digital Television Receiver and Components..., and the sale within the United States after importation of certain electronic devices having a digital... for this investigation may be viewed on the Commission's electronic docket (EDIS) at...

  16. Microbial mineralization of cis-dichloroethene and vinyl chloride as a component of natural attenuation of chloroethene contaminants under conditions identified in the field as anoxic

    USGS Publications Warehouse

    Bradley, Paul M.

    2012-01-01

    Chlororespiration is a key component of remediation at many chloroethene-contaminated sites. In some instances, limited accumulation of reductive dechlorination daughter products may suggest that natural attenuation is not adequate for site remediation. This conclusion is justified when evidence for parent compound (tetrachloroethene, PCE, or trichloroethene, TCE) degradation is lacking. For many chloroethene-contaminated shallow aquifer systems, however, non-conservative losses of the parent compounds are clear but the mass balance between parent compound attenuation and accumulation of reductive dechlorination daughter products is incomplete. Incomplete mass balance indicates a failure to account for important contaminant attenuation mechanisms, and is consistent with contaminant degradation to non-diagnostic mineralization products. An ongoing technical debate over the potential for mineralization of dichloroethene (DCE) and vinyl chloride (VC) to CO2 in the complete absence of diatomic oxygen has largely obscured the importance of microbial DCE/VC mineralization at dissolved oxygen (DO) concentrations below the current field standard (DO < 0.1-0.5 milligrams per liter) for nominally anoxic conditions. This study demonstrates that oxygen-based microbial mineralization of DCE and VC can be substantial under field conditions that are frequently characterized as "anoxic." Because mischaracterization of operant contaminant biodegradation processes can lead to expensive and ineffective remedial actions, a modified framework for assessing the potential importance of oxygen during chloroethene biodegradation was developed.

  17. Effect of Electrostatic Discharge on Electrical Characteristics of Discrete Electronic Components

    NASA Technical Reports Server (NTRS)

    Wysocki, Phil; Vashchenko, Vladislav; Celaya, Jose; Saha, Sankalita; Goebel, Kai

    2009-01-01

    This article reports on preliminary results of a study conducted to examine how temporary electrical overstress seed fault conditions in discrete power electronic components that cannot be detected with reliability tests but impact longevity of the device. These defects do not result in formal parametric failures per datasheet specifications, but result in substantial change in the electrical characteristics when compared with pristine device parameters. Tests were carried out on commercially available 600V IGBT devices using transmission line pulse (TLP) and system level ESD stress. It was hypothesized that the ESD causes local damage during the ESD discharge which may greatly accelerate degradation mechanisms and thus reduce the life of the components. This hypothesis was explored in simulation studies where different types of damage were imposed to different parts of the device. Experimental results agree qualitatively with the simulation for a number of tests which will motivate more in-depth modeling of the damage.

  18. The study of ionization by electron impact of a substance simulating spent nuclear fuel components

    NASA Astrophysics Data System (ADS)

    Antonov, N. N.; Bochkarev, E. I.; Gavrikov, A. V.; Samokhin, A. A.; Smirnov, V. P.

    2015-11-01

    Plasma sources of model substances are necessary to solve problems associated with development of the spent nuclear fuel (SNF) plasma separation method. Lead was chosen to simulate kinetic and dynamic properties of the heavy SNF components. In this paper we present the results of a study of a lead vapor discharge with a lead concentration of 1012-1013 cm-3. Ionization was carried out by an electron beam (with energy of up to 500 eV per electron) inside a centimeter gap between planar electrodes. The discharge was numerically modeled using the hydrodynamic and single-particle approximation. Current-voltage characteristics and single ionization efficiency were obtained as functions of the vapors concentration and thermoelectric current. An ion current of hundreds of microamperes at the ionization efficiency near tenths of a percent was experimentally obtained. These results are in good agreement with our model.

  19. Space Radiation Shielding Studies for Astronaut and Electronic Component Risk Assessment

    NASA Technical Reports Server (NTRS)

    Fuchs, Jordan Robert

    2010-01-01

    The dosimetry component of the Center for Radiation Engineering and Science for Space Exploration (CRESSE) will design, develop and characterize the response of a suite of radiation detectors and supporting instrumentation and electronics with three primary goals that will: (1) Use established space radiation detection systems to characterize the primary and secondary radiation fields existing in the experimental test-bed zones during exposures at particle accelerator facilities. (2) Characterize the responses of newly developed space radiation detection systems in the experimental test-bed zones during exposures at particle accelerator facilities, and (3) Provide CRESSE collaborators with detailed dosimetry information in experimental test-bed zones.

  20. Quantitative determination of the mineral distribution in different collagen zones of calcifying tendon using high voltage electron microscopic tomography

    NASA Technical Reports Server (NTRS)

    McEwen, B. F.; Song, M. J.; Landis, W. J.

    1991-01-01

    High voltage electron microscopic tomography was used to make the first quantitative determination of the distribution of mineral between different regions of collagen fibrils undergoing early calcification in normal leg tendons of the domestic turkey, Meleagris gallopavo. The tomographic 3-D reconstruction was computed from a tilt series of 61 different views spanning an angular range of +/- 60 degrees in 2 degrees intervals. Successive applications of an interactive computer operation were used to mask the collagen banding pattern of either hole or overlap zones into separate versions of the reconstruction. In such 3-D volumes, regions specified by the mask retained their original image density while the remaining volume was set to background levels. This approach was also applied to the mineral crystals present in the same volumes to yield versions of the 3-D reconstructions that were masked for both the crystal mass and the respective collagen zones. Density profiles from these volumes contained a distinct peak corresponding only to the crystal mass. A comparison of the integrated density of this peak from each profile established that 64% of the crystals observed were located in the collagen hole zones and 36% were found in the overlap zones. If no changes in crystal stability occur once crystals are formed, this result suggests the possibilities that nucleation of mineral is preferentially and initially associated with the hole zones, nucleation occurs more frequently in the hole zones, the rate of crystal growth is more rapid in the hole zones, or a combination of these alternatives. All lead to the conclusion that the overall accumulation of mineral mass is predominant in the collagen hole zones compared to overlap zones during early collagen fibril calcification.

  1. Process development for electron beam joining of ceramic and glass components

    SciTech Connect

    Turman, B.N.; Glass, S.J.; Yang, P.; Gerstle, F.P.; Halbleib, J.A.; Voth, T.E.; McKenzie, B.; Clifford, J.R.; Habiger, K.

    1997-11-01

    The purpose of this project is to develop and extend the electron beam joining process to applications related to Mo/Al{sub 2}O{sub 3} cermets for neutron tube fabrication, glass seals for flat panel displays, and ceramics for structural applications. The key issue is the identification of the allowable operating ranges that produce thermal conditions favorable to robust joining and sealing. High strength, hermetic braze joints between ceramic components have been produced using high energy electron beams. With a penetration depth into a typical ceramic of {approximately} 1 cm for a 10 MeV electron beam, this method provides the capability for rapid, transient brazing operations where temperature control of heat sensitive components is essential. The method deposits energy directly into a buried joint, allowing otherwise inaccessible interfaces to be brazed. The combination of transient heating, with higher thermal conductivity, lower heat capacity, and lower melting temperature of braze metals relative to the ceramic materials, enables a pulsed high power beam to melt a braze metal without producing excessive ceramic temperatures. The authors have demonstrated the feasibility of this process related to ceramic coupons a well as ceramic and glass tubes and cylindrical shapes. The transient thermal response was predicted, using as input the energy absorption predicted from the coupled electron-photon and thermal transport analysis. The joining experiments were conducted with an RF linear accelerator at 10--13 MV. Joining experiments have provided high strength joints between alumina and alumina and between alumina and cermet joints in cylindrical geometry. These joints provided good hermetic seals.

  2. Identification of concrete deteriorating minerals by polarizing and scanning electron microscopy

    SciTech Connect

    Gregerova, Miroslava; Vsiansky, Dalibor

    2009-07-15

    The deterioration of concrete represents one of the most serious problems of civil engineering worldwide. Besides other processes, deterioration of concrete consists of sulfate attack and carbonation. Sulfate attack results in the formation of gypsum, ettringite and thaumasite in hardened concrete. Products of sulfate attack may cause a loss of material strength and a risk of collapse of the concrete constructions. The authors focused especially on the microscopical research of sulfate attack. Concrete samples were taken from the Charles Bridge in Prague, Czech Republic. A succession of degrading mineral formation was suggested. Microscope methods represent a new approach to solving the deterioration problems. They enable evaluation of the state of concrete constructions and in cooperation with hydro-geochemistry, mathematics and statistics permit prediction of the durability of a structure. Considering the number of concrete constructions and their age, research of concrete deterioration has an increasing importance. The results obtained can also be useful for future construction, because they identify the risk factors associated with formation of minerals known to degrade structures.

  3. A World of Minerals in Your Mobile Device

    USGS Publications Warehouse

    Jenness, Jane E.; Ober, Joyce A.; Wilkins, Aleeza M.; Gambogi, Joseph

    2016-09-15

    Mobile phones and other high-technology communications devices could not exist without mineral commodities. More than one-half of all components in a mobile device—including its electronics, display, battery, speakers, and more—are made from mined and semiprocessed materials (mineral commodities). Some mineral commodities can be recovered as byproducts during the production and processing of other commodities. As an example, bauxite is mined for its aluminum content, but gallium is recovered during the aluminum production process. The images show the ore minerals (sources) of some mineral commodities that are used to make components of a mobile device. On the reverse side, the map and table depict the major source countries producing these mineral commodities along with how these commodities are used in mobile devices. For more information on minerals, visit http://minerals.usgs.gov.

  4. A world of minerals in your mobile device

    USGS Publications Warehouse

    Jenness, Jane E.; Ober, Joyce A.; Wilkins, Aleeza M.; Gambogi, Joseph

    2016-09-15

    Mobile phones and other high-technology communications devices could not exist without mineral commodities. More than one-half of all components in a mobile device—including its electronics, display, battery, speakers, and more—are made from mined and semiprocessed materials (mineral commodities). Some mineral commodities can be recovered as byproducts during the production and processing of other commodities. As an example, bauxite is mined for its aluminum content, but gallium is recovered during the aluminum production process. The images show the ore minerals (sources) of some mineral commodities that are used to make components of a mobile device. On the reverse side, the map and table depict the major source countries producing these mineral commodities along with how these commodities are used in mobile devices. For more information on minerals, visit http://minerals.usgs.gov.

  5. Effect of six-month hypokinesia in dogs on mineral component, reconstruction and mechanical properties of bone tissue

    NASA Technical Reports Server (NTRS)

    Volozhin, A. I.; Pavlova, M. P.; Muradov, I. S.; Stupakov, G. P.; Korzhenyants, V. A.

    1980-01-01

    Ca45 incorporation into the bones of the limbs, particularly in the area of the muscle attachment increased in dogs as a result of 6 month hypokinesia. There were no phenomena of osteoporosis in the cortical layer of the diaphyses; however, changes in the form of osteons, an increase in the number of anastomoses between the channels and the thinning of the subperiosteal layer pointed to disturbances of the bone tissue reconstruction. Mineral saturation of the bone microstructures of the experimental dogs had a tendency to rise. No changes in the mechanical properties of the long bones occurred as a result of hypokinesia in dogs.

  6. An ex-vivo comparative study of root-end marginal adaptation using grey mineral trioxide aggregate, white mineral trioxide aggregate, and Portland cement under scanning electron microscopy

    PubMed Central

    Baranwal, Akash Kumar; Paul, Mohan L.; Mazumdar, Dibyendu; Adhikari, Haridas Das; Vyavahare, Nishant K.; Jhajharia, Kapil

    2015-01-01

    Context: Where nonsurgical endodontic intervention is not possible, or it will not solve the problem, surgical endodontic treatment must be considered. A major cause of surgical endodontic failures is an inadequate apical seal, so the use of the suitable substance as root-end filling material that prevents egress of potential contaminants into periapical tissue is very critical. Aims: The aim of the present ex-vivo study was to compare and evaluate the three root-end filling materials of mineral trioxide aggregate (MTA) family (white MTA [WMTA], grey MTA [GMTA] and Portland cement [PC]) for their marginal adaptation at the root-end dentinal wall using scanning electron microscopy (SEM). Materials and Methods: Sixty human single-rooted teeth were decoronated, instrumented, and obturated with Gutta-percha. After the root-end resection and apical cavity preparation, the teeth were randomly divided into three-experimental groups (each containing 20 teeth) and each group was filled with their respective experimental materials. After longitudinal sectioning of root, SEM examination was done to determine the overall gap between retrograde materials and cavity walls in terms of length and width of the gap (maximum) at the interface. Descriptive statistical analysis was performed to calculate the means with corresponding standard errors, median and ranges along with an analysis of variance and Tukey's test. Results: The least overall gap was observed in GMTA followed by PC and WMTA. While after statistically analyzing the various data obtained from different groups, there was no significant difference among these three groups in terms of marginal adaptation. Conclusion: GMTA showed the best overall adaptation to root dentinal wall compared to PC and WMTA. Being biocompatible and cheaper, the PC may be an alternative but not a substitute for MTA. PMID:26430305

  7. Optical coating performance for heat reflectors of JWST-ISIM electronic component

    NASA Astrophysics Data System (ADS)

    Quijada, Manuel A.; Bousquet, Robert; Garrison, Matt; Perrygo, Chuck; Threat, Felix; Rashford, Robert

    2008-07-01

    The James Webb Space Telescope (JWST) consists of an infrared-optimized Optical Telescope Element (OTE) that is cooled down to 40 degrees Kelvin. A second adjacent component to the OTE is the Integrated Science Instrument Module, or ISIM. This module includes the electronic compartment, which provides the mounting surfaces and ambient thermally controlled environment for the instrument control electronics. Dissipating the 200 watts generated from the ISIM structure away from the OTE is of paramount importance so that the spacecraft's own heat does not interfere with the infrared light detected from distant cosmic sources. This technical challenge is overcome by a thermal subsystem unit that provides passive cooling to the ISIM control electronics. The proposed design of this thermal radiator consists of a lightweight structure made out of composite materials and low-emittance metal coatings. In this paper, we will present characterizations of the coating emittance, bidirectional reflectance, and mechanical structure design that will affect the performance of this passive cooling reflector.

  8. Enhancement of hadron-electron discrimination in calorimeters by detection of the neutron component

    NASA Astrophysics Data System (ADS)

    Adriani, O.; Bonechi, L.; Bongi, M.; Bottai, S.; Calamai, M.; Castellini, G.; D'Alessandro, R.; Grandi, M.; Papini, P.; Ricciarini, S.; Sguazzoni, G.; Sona, P.; Sorichetti, G.

    2011-02-01

    In many physics experiments where calorimeters are employed, the requirement of an accurate energy measurement is accompanied by the requirement of very high hadron-electron discrimination power. Normally the latter requirement is achieved by designing a high-granularity detector with sufficient depth so that the showers can fully develop. This method has many drawbacks ranging from the high number of electronic channels to the high mass of the detector itself. Some of these drawbacks may in fact severely limit the deployment of such a detector in many experiments, most notably in space-based ones. Another method, proposed by our group and currently under investigation, relies on the use of scintillation detectors which are sensitive to the neutron component of the hadron showers. Here a review of the current status will be presented starting with the simulations performed both with GEANT4 and FLUKA. A small prototype detector has been built and has been tested in a high-energy pion/electron beam behind a "shallow" calorimeter. Results are encouraging and indicate that it is possible to enhance the discrimination power of an existing calorimeter by the addition of a small-mass neutron detector, thus paving the way for better performing astroparticle experiments.

  9. Development of Standardized Power Electronic Components, Subsystems, and Systems for Increased Modularity and Scalability

    SciTech Connect

    Chakraborty, S.; Pink, C.; Price, J.; Kroposki, B.; Kern, G.

    2007-11-01

    Power electronics devices hold substantial promise for making distributed energy applications more efficient and cost effective. This project is motivated towards developing and testing inverters that will allow distributed energy systems to provide ancillary services such as voltage and VAR regulation, and increased grid reliability by seamlessly transitioning between grid-tied and stand-alone operation modes. The objectives of this project are to identify system integration and optimization issues and technologies and to provide solutions through research, analysis, and testing of power electronic interfaces for distributed energy applications that are cost-competitive and have substantially faster response times than conventional technologies. In addition, the testing of power electronics interfaces will develop a technical basis for performance assessment for distributed energy systems, subsystems, and components that will finally create a foundation for standardized measurements and test procedures. The ultimate goal for this research is to advance the potential benefits of distributed energy to provide ancillary services, enhance power system reliability, and allow customer choice.

  10. Electron Energy-Loss Spectroscopy: Fundamentals and applications in the characterization of minerals

    SciTech Connect

    Krishnan, K.M.

    1989-04-01

    The combined use of an energy-loss spectrometer and an analytical electron microscope with fine probe forming capabilities provides a wealth of information about the sample at high spatial resolution. Fundamental principles governing the physics of the interaction between the fast electron and a thin foil sample, to account for the fine structure in the inelastically scattered fast electron distribution (Electron-Energy Loss Spectroscopy, EELS), will be reviewed. General application of EELS is in the area of low atomic number elements (Z < 11) microanalysis, where it significantly complements the more widely used Energy Dispersive X-ray Spectroscopy (EDXS). However, a careful analysis of the low loss plasmon oscillations and the fine structure in the core-loss edges, can provide additional information related to the bonding and electronic structure of the sample. An illustration of this is presented from our study of Cdelta diamond residue from the Allende carbonaceous chondrite. Combination of EELS with channeling effects can provide specific site occupation/valence information in crystalline materials. Details of this novel crystallographic method will be outlined and illustrated with an example of the study of chromite spinels. Finally, some pertinent experimental details will be discussed. 7 figs.

  11. Improved source assessment of Si, Al and related mineral components to PM10 based on a daily sampling procedure.

    PubMed

    Peng, Ge; Puxbaum, Hans; Bauer, Heidi; Jankowski, Nicole; Shi, Yao

    2010-01-01

    Samples obtained from an industrialized valley in the East Alpine region were collected daily for a half year and analyzed using X-ray fluorescence to examine the elements Si, Al, Fe, Ca, Mg, Na, K, Zn, P, S and Cl. Some factors affecting the changes of these elements were considered, including time, elemental correlations, weekday, weekend and seasonal changes. Diagnostic analysis provided an insight into a decoupling behavior that occursin siliceous and carbonates minerals. A decrease in Si and Al and an increase in carbonates, Na, K, Zn and P were observed during the cold season. However, a consistently high correlation of Si and Al was observed in all seasons. It was established that such high levels originated from street surface abrasion. The increase in variability and absolute levels of carbonates during the cold season was demonstrated by adding carbonates to the street surface as gritting material to increase the grip on snowy surfaces. A marked increase in Na and Cl was observed in winter which may have been caused by thaw salt that is widely used in winter in Austria. This was associated with a significant increase in K, Zn, and P in the cold season that was the result of domestic space heating with wood. PM10 levels in December were 12 microg/m3 and were higher than levels detected in July. It was established that such high levels originated from mineral oxides, wood smoke, and inorganic ionic material(s).

  12. Water Soluble Components of ‘Osteocare’ Promote Cell Proliferation, Differentiation, and Matrix Mineralization in Human Osteoblast-Like SaOS-2 Cells

    PubMed Central

    Varma, Sandeep R.; Sharath Kumar, L. M.; Vidyashankar, Satyakumar; Patki, Pralhad Sadashiv

    2014-01-01

    Osteocare, a herbal formulation, has been found to be very effective in bone mineralization and support of the microstructure of bone tissue. The water-soluble components of Osteocare (WSCO) induced osteogenic activity in human osteoblast-like SaOS-2 cells. The addition of WSCO (100 μg/ml) to SaOS-2 cells was effective in increasing the cell proliferation by 41.49% and DNA content by 1.9-fold. WSCO increased matrix mineralization in SaOS-2 cells by increased alkaline phosphatase levels and calcium-rich deposits as observed by Alizarin red staining. WSCO markedly increased mRNA expression for osteopontin (OPN), osteocalcin (OCN), type I collagen (Col I) in SaOS-2 cells, and it down-regulated IL-6 mRNA levels in SaOS-2 cells. The present study showed that WSCO plays an important role in osteoblastic bone formation through enhanced activities of ALP, Col I, bone matrix proteins such as OPN and OCN, down-regulation of cytokines like IL-6, as well as promoting mineralization in SaOS-2 cells. PMID:24959407

  13. Water Soluble Components of 'Osteocare' Promote Cell Proliferation, Differentiation, and Matrix Mineralization in Human Osteoblast-Like SaOS-2 Cells.

    PubMed

    Varma, Sandeep R; Sharath Kumar, L M; Vidyashankar, Satyakumar; Patki, Pralhad Sadashiv

    2014-06-01

    Osteocare, a herbal formulation, has been found to be very effective in bone mineralization and support of the microstructure of bone tissue. The water-soluble components of Osteocare (WSCO) induced osteogenic activity in human osteoblast-like SaOS-2 cells. The addition of WSCO (100 μg/ml) to SaOS-2 cells was effective in increasing the cell proliferation by 41.49% and DNA content by 1.9-fold. WSCO increased matrix mineralization in SaOS-2 cells by increased alkaline phosphatase levels and calcium-rich deposits as observed by Alizarin red staining. WSCO markedly increased mRNA expression for osteopontin (OPN), osteocalcin (OCN), type I collagen (Col I) in SaOS-2 cells, and it down-regulated IL-6 mRNA levels in SaOS-2 cells. The present study showed that WSCO plays an important role in osteoblastic bone formation through enhanced activities of ALP, Col I, bone matrix proteins such as OPN and OCN, down-regulation of cytokines like IL-6, as well as promoting mineralization in SaOS-2 cells.

  14. 32 CFR 21.565 - Must DoD Components' electronic systems accept Data Universal Numbering System (DUNS) numbers?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Data Universal Numbering System (DUNS) numbers? 21.565 Section 21.565 National Defense Department of... Components' electronic systems accept Data Universal Numbering System (DUNS) numbers? The DoD Components must... DUNS numbers with a copy to: Director for Basic Sciences, ODDR&E, 3040 Defense Pentagon, Washington,...

  15. 32 CFR 21.565 - Must DoD Components' electronic systems accept Data Universal Numbering System (DUNS) numbers?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Data Universal Numbering System (DUNS) numbers? 21.565 Section 21.565 National Defense Department of... Components' electronic systems accept Data Universal Numbering System (DUNS) numbers? The DoD Components must... DUNS numbers with a copy to: Director for Basic Sciences, ODDR&E, 3040 Defense Pentagon, Washington,...

  16. 32 CFR 21.565 - Must DoD Components' electronic systems accept Data Universal Numbering System (DUNS) numbers?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Data Universal Numbering System (DUNS) numbers? 21.565 Section 21.565 National Defense Department of... Components' electronic systems accept Data Universal Numbering System (DUNS) numbers? The DoD Components must... DUNS numbers with a copy to: Director for Basic Sciences, ODDR&E, 3040 Defense Pentagon, Washington,...

  17. 76 FR 53154 - In the Matter of Certain Electronic Paper Towel Dispensing Devices and Components Thereof; Notice...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-25

    ... COMMISSION In the Matter of Certain Electronic Paper Towel Dispensing Devices and Components Thereof; Notice... Commission has determined not to review an initial determination (``ID'') (Order No. 36) of the presiding... Section 337 by defaulting respondents in Inv. No. 337-TA- 718, Certain Electronic Paper Towel...

  18. Exploring the Relationships between the Electronic Health Record System Components and Patient Outcomes in an Acute Hospital Setting

    ERIC Educational Resources Information Center

    Wiggley, Shirley L.

    2011-01-01

    Purpose: The purpose of this study was to examine the relationship between the electronic health record system components and patient outcomes in an acute hospital setting, given that the current presidential administration has earmarked nearly $50 billion to the implementation of the electronic health record. The relationship between the…

  19. Component-Level Electronic-Assembly Repair (CLEAR) Synthetic Instrument Capabilities Assessment and Test Report

    NASA Technical Reports Server (NTRS)

    Oeftering, Richard C.; Bradish, Martin A.

    2011-01-01

    The role of synthetic instruments (SIs) for Component-Level Electronic-Assembly Repair (CLEAR) is to provide an external lower-level diagnostic and functional test capability beyond the built-in-test capabilities of spacecraft electronics. Built-in diagnostics can report faults and symptoms, but isolating the root cause and performing corrective action requires specialized instruments. Often a fault can be revealed by emulating the operation of external hardware. This implies complex hardware that is too massive to be accommodated in spacecraft. The SI strategy is aimed at minimizing complexity and mass by employing highly reconfigurable instruments that perform diagnostics and emulate external functions. In effect, SI can synthesize an instrument on demand. The SI architecture section of this document summarizes the result of a recent program diagnostic and test needs assessment based on the International Space Station. The SI architecture addresses operational issues such as minimizing crew time and crew skill level, and the SI data transactions between the crew and supporting ground engineering searching for the root cause and formulating corrective actions. SI technology is described within a teleoperations framework. The remaining sections describe a lab demonstration intended to show that a single SI circuit could synthesize an instrument in hardware and subsequently clear the hardware and synthesize a completely different instrument on demand. An analysis of the capabilities and limitations of commercially available SI hardware and programming tools is included. Future work in SI technology is also described.

  20. Design and characterization of the annular cathode high current pulsed electron beam source for circular components

    NASA Astrophysics Data System (ADS)

    Jiang, Wei; Wang, Langping; Wang, Xiaofeng

    2016-08-01

    In order to irradiate circular components with high current pulsed electron beam (HCPEB), an annular cathode based on carbon fiber bunches was designed and fabricated. Using an acceleration voltage of 25 kV, the maximum pulsed irradiation current and energy of this annular cathode can reach 7.9 kA and 300 J, respectively. The irradiation current density distribution of the annular cathode HCPEB source measured along the circumferential direction shows that the annular cathode has good emission uniformity. In addition, four 9310 steel substrates fixed uniformly along the circumferential direction of a metal ring substrate were irradiated by this annular cathode HCPEB source. The surface and cross-section morphologies of the irradiated samples were characterized by scanning electron microscopy (SEM). SEM images of the surface reveal that crater and surface undulation have been formed, which hints that the irradiation energy of the HCPEB process is large enough for surface modification of 9310 steel. Meanwhile, SEM cross-section images exhibit that remelted layers with a thickness of about 5.4 μm have been obtained in all samples, which proves that a good practical irradiation uniformity can be achieved by this annular cathode HCPEB source.

  1. Key components of anaphylaxis management plans: consensus findings from a national electronic Delphi study

    PubMed Central

    Worth, Allison; Nurmatov, Ulugbek; Sheikh, Aziz

    2010-01-01

    Objectives There is no international consensus on the components of anaphylaxis management plans and responsibility for their design and delivery is contested. We set out to establish consensus among relevant specialist and generalist clinicians on this issue to inform future randomized controlled trials. Design A two-round electronic Delphi study completed by a 25-person, multidisciplinary expert panel. Participants scored the importance of a range of statements on anaphylaxis management, identified from a systematic review of the literature, on a five-point scale ranging from ‘very important’ to ‘irrelevant’. Consensus was defined a priori as being achieved if 80% or more of panel members rated a statement as ‘important’ or ‘very important’ after Round 2. Setting Primary and secondary care and academic settings in the UK and Ireland. Participants Twenty-five medical, nursing and allied health professionals. Main outcome measures Consensus on the key components of anaphylaxis management plans. Results The response rate was 84% (n = 21) for Round 1 and 96% (n = 24) for Round 2. The key components of emergency care on which consensus was achieved included: awareness of trigger factors (100%); recognition and emergency management of reactions of different severity (100%); and clear information on adrenaline (epinephrine) use (100%). Consensus on longer-term management issues included: clear written guidelines on anaphylaxis management (96%); annual review of plans (87%); and plans that were tailored to individual needs (82%). Conclusions This national consensus-building exercise generated widespread agreement that emergency plans need to be simple, clear and generic, making them easy to implement in a crisis. In contrast, long-term plans need to be negotiated between patient/carers and professionals, and tailored to individual needs. The effectiveness of this expert-agreed long-term plan now needs to be evaluated rigorously. PMID:21103134

  2. Role of soil mineral components in the stabilization of organic matter in Umbric Ferralsols of South Brazil

    NASA Astrophysics Data System (ADS)

    Velasco-Molina, Marta; Berns, Anne E.; Macias, Felipe; Knicker, Heike

    2013-04-01

    Climatic conditions of subtropical and tropical regions support fast carbon (C) mineralization, and thus an accelerated degradation of soil organic matter (SOM) if compared to temperate region (Sánchez & Logan, 1992). However, even in those regions, there are still soil horizons that show notable C accumulation. Examples for the latter are umbric horizons in typical tropical soils, such as Ferralsols. The occurrence of this soils with thick umbric epipedons (× 100 cm thickness) in areas of South Brazil is a paradox, that still needs a better understanding (Marques et al., 2011), in particular since the processes that are responsible for the thickness and darkness of the umbric horizons are of special interest with respect to the role of soils as carbon sink. One major contributor to SOM stabilization represents the soil mineral phase. Therefore the main goal of this work its to study the impact of this factor on the SOM sequestration in Umbric Ferralsols from Atibaia, Campinas (São Paulo State) and Chapecó (Santa Catarina State) developed under different environmental conditions. With this objective the mineral fractions have been isolated by selective extraction of iron and aluminium oxides with different extracting solutions (sodium pyrophosphate, ammonium oxalate and dithionite-citrate-bicarbonate solution) and related to SOM quality and quantity. The latter was studied by the use of solid-state cross polarisation (CPMAS) 13C NMR spectroscopy after demineralization with hydrofluoric acid (Gonçalves et al., 2003). Quantification of the NMR spectra was performed by integration of the respective chemical shift regions under consideration of the contribution of spinning side bands. For our study the following regions were distinguished (Knicker & Lüdemann, 1995): alkyl C (0-45 ppm), N-alkyl C (45-60ppm), O-alkyl C (60-110 ppm), aryl C (110-160 ppm), carbonyl C (160-245 ppm). Preliminary results show that, the minimum vertical variation of total Fe into the

  3. Clay Minerals

    SciTech Connect

    Mueller, Karl T.; Sanders, Rebecca L.; Washton, Nancy M.

    2014-03-14

    Clay minerals are important components of the environment and are involved or implicated in processes such as the uptake of pollutants and the release of nutrients and as potential platforms for a number of chemical reactions. Owing to their small particle sizes (typically, on the order of microns or smaller) and mixing with a variety of other minerals and soil components, advanced characterization methods are needed to study their structures, dynamics, and reactivities. In this article, we describe the use of solid-state NMR methods to characterize the structures and chemistries of clay minerals. Early one-pulse magic-angle spinning (MAS) NMR studies of 27Al and 29Si have now been enhanced and extended with new studies utilizing advanced methodologies (such as Multiple Quantum MAS) as well as studies of less-sensitive nuclei. In additional work, the issue of reactivity of clay minerals has been addressed, including studies of reactive surface area in the environment. Utilizations of NMR-sensitive nuclides within the clay minerals themselves, and in molecules that react with specific sites on the clay mineral surfaces, have aided in understanding the reactivity of these complex aluminosilicate systems.

  4. Single-component chemically amplified resist materials for electron-beam and x-ray lithography

    NASA Astrophysics Data System (ADS)

    Novembre, Anthony E.; Tai, Woon W.; Kometani, Janet M.; Hanson, James E.; Nalamasu, Omkaram; Taylor, Gary N.; Reichmanis, Elsa; Thompson, Larry F.

    1991-06-01

    Copolymers of 4-tert-butoxycarbonyloxystyrene (TBS) and sulfur dioxide (SO2) have been found to act as sensitive x-ray ((lambda) equals 14 angstrom) and moderately sensitive electron-beam, single component, chemically amplified, aqueous base soluble positive acting resists. The x-ray and electron-beam response of these materials was a function of copolymer composition, where an increase in the sulfur dioxide content enhanced the resist sensitivity. Initial investigation into the radiation induced reaction mechanism provided evidence that acid formation occurs via polymer main chain scission. It is proposed that at the scission sites radical species are produced which in turn are responsible for the formation of the acidic moieties. Heat treatment of resist films after exposure converted the copolymers to poly(4- hydroxystyrene sulfone) and permitted the exposed film areas to be developed in an aqueous base solution. Preliminary lithographic evaluation has resolved 0.5 micrometers line and space patterns in 0.65 micrometers thick 1.75/1 TBS/SO2 resist films using an x-ray dose of 10 mJ/cm2. For a resist having a composition of 2.1/1 TBS/SO2, 0.25 micrometers line and space features where delineated using an electron-beam dose of 90 (mu) C/cm2 at 30 KV. In addition, minimal surface residue of the exposed areas of the resist film after development was observed when the time interval between the exposure and the post-exposure baking steps was varied from 2-10 minutes.

  5. Microfabrication of passive electronic components with printed graphene-oxide deposition

    NASA Astrophysics Data System (ADS)

    Sinar, Dogan; Knopf, George K.; Nikumb, Suwas

    2014-03-01

    Flexible electronic circuitry is an emerging technology that will significantly impact the future of healthcare and medicine, food safety inspection, environmental monitoring, and public security. Recent advances in drop-on-demand printing technology and electrically conductive inks have enabled simple electronic circuits to be fabricated on mechanically flexible polymers, paper, and bioresorbable silk. Research has shown that graphene, and its derivative formulations, can be used to create low-cost electrically conductive inks. Graphene is a one atom thick two-dimensional layer composed of carbon atoms arranged in a hexagonal lattice forming a material with very high fracture strength, high Young's Modulus, and low electrical resistance. Non-conductive graphene-oxide (GO) inks can also be synthesized from inexpensive graphite powders. Once deposited on the flexible substrate the electrical conductivity of the printed GO microcircuit traces can be restored through thermal reduction. In this paper, a femtosecond laser with a wavelength of 775nm and pulse width of 120fs is used to transform the non-conductive printed GO film into electrically conductive oxygen reduced graphene-oxide (rGO) passive electronic components by the process of laser assisted thermal reduction. The heat affected zone produced during the process was minimized because of the femtosecond pulsed laser. The degree of conductivity exhibited by the microstructure is directly related to the laser power level and exposure time. Although rGO films have higher resistances than pristine graphene, the ability to inkjet print capacitive elements and modify local resistive properties provides for a new method of fabricating sensor microcircuits on a variety of substrate surfaces.

  6. A spin rotator for detecting all three magnetization vector components by spin-polarized scanning electron microscopy

    NASA Astrophysics Data System (ADS)

    Kohashi, Teruo; Matsuyama, Hideo; Koike, Kazuyuki

    1995-12-01

    A spin rotator for observing magnetic domains with all three magnetization components of a sample surface by spin-polarized scanning electron microscopy (spin SEM) has been developed. The spin rotator is placed between the sample and the spin detector in a spin SEM, and can rotate the polarization vector of secondary electrons by π/2. Although the spin detector itself can detect only two independent polarization components, the rotation of polarization makes third-component detection possible. The conventional spin rotator, which is a well-known energy filter named a Wien filter, has been much improved to have a large focusing area by using hyperbolic cylindrical pole pieces as a magnet and several auxiliary electrodes. As a result, all the secondary electrons emitted from the area of a surface as large as 1 mm in diameter can pass the spin rotator with uniform spin rotation, and the distribution of all three magnetization components can be imaged successfully by spin SEM.

  7. Electron- and Photon-stimulated Desorption of Alkali Atoms from Lunar Sample and a Model Mineral Surface

    NASA Technical Reports Server (NTRS)

    Yakshinskiy, B. V.; Madey, T. E.

    2003-01-01

    We report recent results on an investigation of source mechanisms for the origin of alkali atoms in the tenuous planetary atmospheres, with focus on non-thermal processes (photon stimulated desorption (PSD), electron stimulated desorption (ESD), and ion sputtering). Whereas alkaline earth oxides (MgO, CaO) are far more abundant in lunar samples than alkali oxides (Na2O, K2O), the atmosphere of the Moon contains easily measurable concentrations of Na and K, while Ca and Mg are undetected there; traces of Ca have recently been seen in the Moon's atmosphere (10-3 of Na). The experiments have included ESD, PSD and ion sputtering of alkali atoms from model mineral surface (amorphous SiO2) and from a lunar basalt sample obtained from NASA. The comparison is made between ESD and PSD efficiency of monovalent alkalis (Na, K) and divalent alkaline earths (Ba, Ca).The ultrahigh vacuum measurement scheme for ESD and PSD of Na atoms includes a highly sensitive alkali metal detector based on surface ionization, and a time-of-flight technique. For PSD measurements, a mercury arc light source (filtered and chopped) is used. We find that bombardment of the alkali covered surfaces by ultraviolet photons or by low energy electrons (E>4 eV) causes desorption of hot alkali atoms. This results are consistent with the model developed to explain our previous measurements of sodium desorption from a silica surface and from water ice: electron- or photon-induced charge transfer from the substrate to the ionic adsorbate causes formation of a neutral alkali atom in a repulsive configuration, from which desorption occurs. The two-electron charge transfer to cause desorption of divalent alkaline eath ions is a less likely process.The data support the suggestion that PSD by UV solar photons is a dominant source process for alkalis in the tenuous lunar atmosphere.

  8. Scanning electron microscopic analysis of the mineralization of type I collagen via a polymer-induced liquid-precursor (PILP) process.

    PubMed

    Olszta, M J; Douglas, E P; Gower, L B

    2003-05-01

    We have put forth the hypothesis that collagen is mineralized during bone formation by means of a polymer-induced liquid-precursor (PILP) process, in which a liquid-phase mineral precursor could be drawn into the gaps and grooves of the collagen fibrils by capillary action, and upon solidification, leave the collagenous matrix embedded with nanoscopic crystallites of hydroxyapatite. This hypothesis is based upon our observations of capillarity seen for liquid-phase mineral precursors generated with calcium carbonate. Here, we demonstrate proof-of-concept of this mechanism by mineralizing Cellagen sponges (type I reconstituted bovine collagen) in the presence of a liquid-precursor phase to calcium carbonate. Scanning electron microscopy (SEM) was used to examine the mineralized collagen, which in combination with selective etching studies, revealed the extent to which the mineral phase infiltrated the collagenous matrix. A roughly periodic array of disk-like crystals was found to be embedded within the collagen fibers, demonstrating that the mineral phase spans across the diameter of the fibers. Some of the morphological features of the mineralized fibers in our in vitro model system are similar to those seen in natural bone (albeit of a different mineral phase), lending support to our hypothesis that these non-equilibrium morphologies might be generated by a PILP process. SEM provides a different perspective on the morphology of bone, and has been useful here for examining the extent of mineralization in composite structures generated via the PILP process. However, further investigation is needed to examine the nanostructural arrangement of the crystallites embedded within the collagenous matrix.

  9. 27 CFR 73.11 - What are the required components and controls for acceptable electronic signatures?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... signatures not based on biometrics. If you use electronic signatures that are not based upon biometrics you...) Electronic signatures based on biometrics. If you use electronic signatures based upon biometrics, they...

  10. 27 CFR 73.11 - What are the required components and controls for acceptable electronic signatures?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... signatures not based on biometrics. If you use electronic signatures that are not based upon biometrics you...) Electronic signatures based on biometrics. If you use electronic signatures based upon biometrics, they...

  11. 27 CFR 73.11 - What are the required components and controls for acceptable electronic signatures?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... signatures not based on biometrics. If you use electronic signatures that are not based upon biometrics you...) Electronic signatures based on biometrics. If you use electronic signatures based upon biometrics, they...

  12. 27 CFR 73.11 - What are the required components and controls for acceptable electronic signatures?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... signatures not based on biometrics. If you use electronic signatures that are not based upon biometrics you...) Electronic signatures based on biometrics. If you use electronic signatures based upon biometrics, they...

  13. Mineralization of collagen may occur on fibril surfaces: evidence from conventional and high-voltage electron microscopy and three-dimensional imaging

    NASA Technical Reports Server (NTRS)

    Landis, W. J.; Hodgens, K. J.; Song, M. J.; Arena, J.; Kiyonaga, S.; Marko, M.; Owen, C.; McEwen, B. F.

    1996-01-01

    The interaction between collagen and mineral crystals in the normally calcifying leg tendons from the domestic turkey, Meleagris gallopavo, has been investigated at an ultrastructural level with conventional and high-voltage electron microscopy, computed tomography, and three-dimensional image reconstruction methods. Specimens treated by either aqueous or anhydrous techniques and resin-embedded were appropriately sectioned and regions of early tendon mineralization were photographed. On the basis of individual photomicrographs, stereoscopic pairs of images, and tomographic three-dimensional image reconstructions, platelet-shaped crystals may be demonstrated for the first time in association with the surface of collagen fibrils. Mineral is also observed in closely parallel arrays within collagen hole and overlap zones. The mineral deposition at these spatially distinct locations in the tendon provides insight into possible means by which calcification is mediated by collagen as a fundamental event in skeletal and dental formation among vertebrates.

  14. Strength of mineral absorption features in the transmitted component of near-infrared reflected light - First results from RELAB. [spectrogoniometer for planetary and lunar surface composition experiments

    NASA Technical Reports Server (NTRS)

    Pieters, C. M.

    1983-01-01

    Bidirectional reflectance measurements are the only type of reflectance data available to the remote observer. For compositional interpretations, data are desired not only for identification of possible mineral components but also for modal abundance. The latter requires detailed information about the strength of absorption features. Using a new laboratory facility, the RELAB, laboratory data in the near infrared are presented that document effects of particle size, mineral mixtures, and viewing geometry for selected materials with well-developed absorption bands. The commonly observed increase in reflectance with decrease in particle size is also observed for absorption bands as well as a related decrease in absorption strength. For small particles in parts of the spectrum of maximum reflectance, however, a minor decrease in reflectance with a decrese in particle size is sometimes observed. Small particles dominate the observed characteristics of particulate surfaces, which contain a range of particle sizes. The mean optical path length (transmission through particles) of reflected radiation measured for a variety of particle sizes has an apparent upper limit of about 2 mm for particles of less than 250 microns. The typical number of particles involved in the optical path is less than 50.

  15. An environmentally friendly technology of disassembling electronic components from waste printed circuit boards.

    PubMed

    Wang, Jianbo; Guo, Jie; Xu, Zhenming

    2016-07-01

    Electronic components (ECs) disassembling from waste printed circuit boards (WPCBs) is the first and essential step in WPCBs recycling chain. Over the past decades, primitive methods like simply heating WPCBs on a coal-heated plate to melt solders are dominated in practice, causing serious environmental pollution and also putting a real threat to the human health. In order to solve this problem, in this article, an automatic system in pilot-scale for ECs disassembling from WPCBs is designed, manufactured, and investigated. This system contains two parts: ECs automatic disassembly and off-gas purification. Meanwhile, WPCBs from television (i.e., TV-WPCBs) and personal computer (i.e., PC-WPCBs) are used for disassembling tests, respectively. When the disassembling temperature, rotating speed, and incubation time are 265±5°C, 10rpm, and 8min, respectively, the solder can be completely removed from both TV-WPCBs and PC-WPCBs. No pollutant is discharged from this system. Finally, the disassembling procedures for ECs from both TV-WPCBs and PC-WPCBs are suggested to promote WPCBs disassembling in an environment-friendly way, without threaten the environment and human health. PMID:27026495

  16. An environmentally friendly technology of disassembling electronic components from waste printed circuit boards.

    PubMed

    Wang, Jianbo; Guo, Jie; Xu, Zhenming

    2016-07-01

    Electronic components (ECs) disassembling from waste printed circuit boards (WPCBs) is the first and essential step in WPCBs recycling chain. Over the past decades, primitive methods like simply heating WPCBs on a coal-heated plate to melt solders are dominated in practice, causing serious environmental pollution and also putting a real threat to the human health. In order to solve this problem, in this article, an automatic system in pilot-scale for ECs disassembling from WPCBs is designed, manufactured, and investigated. This system contains two parts: ECs automatic disassembly and off-gas purification. Meanwhile, WPCBs from television (i.e., TV-WPCBs) and personal computer (i.e., PC-WPCBs) are used for disassembling tests, respectively. When the disassembling temperature, rotating speed, and incubation time are 265±5°C, 10rpm, and 8min, respectively, the solder can be completely removed from both TV-WPCBs and PC-WPCBs. No pollutant is discharged from this system. Finally, the disassembling procedures for ECs from both TV-WPCBs and PC-WPCBs are suggested to promote WPCBs disassembling in an environment-friendly way, without threaten the environment and human health.

  17. Toxicity of electronic waste leachates to Daphnia magna: screening and toxicity identification evaluation of different products, components, and materials.

    PubMed

    Lithner, Delilah; Halling, Maja; Dave, Göran

    2012-05-01

    Electronic waste has become one of the fastest growing waste problems in the world. It contains both toxic metals and toxic organics. The aim of this study was to (1) investigate to what extent toxicants can leach from different electronic products, components, and materials into water and (2) identify which group of toxicants (metals or hydrophobic organics) that is causing toxicity. Components from five discarded electronic products (cell phone, computer, phone modem, keyboard, and computer mouse) were leached in deionised water for 3 days at 23°C in concentrations of 25 g/l for metal components, 50 g/l for mixed-material components, and 100 g/l for plastic components. The water phase was tested for acute toxicity to Daphnia magna. Eighteen of 68 leachates showed toxicity (with immobility of D. magna ≥ 50% after 48 h) and came from metal or mixed-material components. The 8 most toxic leachates, with 48 h EC(50)s ranging from 0.4 to 20 g/l, came from 2 circuit sheets (key board), integrated drive electronics (IDE) cable clips (computer), metal studs (computer), a circuit board (computer mouse), a cord (phone modem), mixed parts (cell phone), and a circuit board (key board). All 5 electronic products were represented among them. Toxicity identification evaluations (with C18 and CM resins filtrations and ethylenediaminetetraacetic acid addition) indicated that metals caused the toxicity in the majority of the most toxic leachates. Overall, this study has shown that electronic waste can leach toxic compounds also during short-term leaching with pure water.

  18. Kingian Co-Evolution of the Water and Mineral/Rock Components for Earth and Mars: Implications for Planetary Habitability (Invited)

    NASA Astrophysics Data System (ADS)

    Baker, V. R.

    2013-12-01

    Planetary habitability may fluctuate episodically against a background provided by the co-evolution of a planet's mineral/rock (geosphere) components and its water (hydrosphere) in relation to its position in a circumstellar system. The water/rock (geosphere/hydrosphere) co-evolution can be inferred from the geological histories of the terrestrial planets of the solar system, particularly from the very extensive understanding of Earth and Mars. Habitability and water/rock co-evolution have components that are tychistic (i.e., driven by chance) and anancastic (i.e., dynamically driven largely by deterministic forces). They also have a final, end-directed (i.e., teleomatic) aspect that operates in accordance with natural laws. This is a larger perspective on the idea of planetary habitability than is generally associated with an astronomical approach, and it incorporates additional insights from a geological perspective on the issue. The geological histories of Mars and Earth are punctuated with critical, short-term epochs of extreme change, which for Earth are known to be associated with major disruptions of its biosphere. These catastrophic epochs can be described as a type of non-Darwinian evolution that was envisioned by the geologist Clarence King. In an 1877 paper King proposed that accelerated evolutionary change occurs during sudden environmental disruptions. Such Kingian disruptions in mineral/rock and water evolution mark the planetary histories of Mars and Earth, including the early formation and condensation of a steam atmosphere, an impacting cataclysm at about 3.9 to 4 Ga, episodes of concentrated volcanism and tectonism, and associated rapid changes in the linked atmosphere and hydrosphere. These disruptions are closely tied to migrations of water between different planetary reservoirs, the nature of planetary accretion, the origin of a physically coupled atmosphere and ocean, the prospects for initiating plate tectonics, and punctuated greenhouse

  19. Electron transfer at the mineral/water interface: Selenium reduction by ferrous iron sorbed on clay

    NASA Astrophysics Data System (ADS)

    Charlet, L.; Scheinost, A. C.; Tournassat, C.; Greneche, J. M.; Géhin, A.; Fernández-Martínez, A.; Coudert, S.; Tisserand, D.; Brendle, J.

    2007-12-01

    The mobility and availability of the toxic metalloid selenium in the environment are largely controlled by sorption and redox reactions, which may proceed at temporal scales similar to that of subsurface water movement under saturated or unsaturated conditions. Since such waters are often anaerobic and rich in Fe 2+, we investigated the long-term (⩽1 month) kinetics of selenite (Se(IV)O3-) sorption to montmorillonite in the presence of Fe 2+ under anoxic conditions. A synthetic montmorillonite was used to eliminate the influence of structural Fe. In the absence of aqueous Fe 2+, selenite was sorbed as outer-sphere sorption complex, covering only part of the positive edge sites, as verified by a structure-based MUSIC model and Se K-edge XAS (X-ray absorption spectroscopy). When selenite was added to montmorillonite previously equilibrated with Fe 2+ solution however, slow reduction of Se and formation of a solid phase was observed with Se K-edge XANES (X-ray absorption near-edge spectroscopy) and EXAFS (extended X-ray absorption fine-structure) spectroscopy. Iterative transformation factor analysis of XANES and EXAFS spectra suggested that only one Se reaction product formed, which was identified as nano-particulate Se(0). Even after one month, only 75% of the initially sorbed Se(IV) was reduced to this solid species. Mössbauer spectrometry revealed that before and after addition and reduction of Se, 5% of total sorbed Fe occurred as Fe(III) species on edge sites of montmorillonite (≈2 mmol kg -1). The only change observed after addition of Se was the formation of a new Fe(II) species (15%) attributed to the formation of an outer-sphere Fe(II)-Se sorption complex. The combined Mössbauer and XAS results hence clearly suggest that the Se and Fe redox reactions are not directly coupled. Based on the results of a companion paper, we hypothesize that the electrons produced in the absence of Se by oxidation of sorbed Fe(II) are stored, for example by formation of

  20. Measurement of the intrinsic electron neutrino component in the T2K neutrino beam with the ND280 detector

    NASA Astrophysics Data System (ADS)

    Abe, K.; Adam, J.; Aihara, H.; Akiri, T.; Andreopoulos, C.; Aoki, S.; Ariga, A.; Ariga, T.; Assylbekov, S.; Autiero, D.; Barbi, M.; Barker, G. J.; Barr, G.; Bass, M.; Batkiewicz, M.; Bay, F.; Bentham, S. W.; Berardi, V.; Berger, B. E.; Berkman, S.; Bertram, I.; Bhadra, S.; Blaszczyk, F. d. M.; Blondel, A.; Bojechko, C.; Bordoni, S.; Boyd, S. B.; Brailsford, D.; Bravar, A.; Bronner, C.; Buchanan, N.; Calland, R. G.; Caravaca Rodríguez, J.; Cartwright, S. L.; Castillo, R.; Catanesi, M. G.; Cervera, A.; Cherdack, D.; Christodoulou, G.; Clifton, A.; Coleman, J.; Coleman, S. J.; Collazuol, G.; Connolly, K.; Cremonesi, L.; Dabrowska, A.; Danko, I.; Das, R.; Davis, S.; de Perio, P.; De Rosa, G.; Dealtry, T.; Dennis, S. R.; Densham, C.; Di Lodovico, F.; Di Luise, S.; Drapier, O.; Duboyski, T.; Duffy, K.; Dufour, F.; Dumarchez, J.; Dytman, S.; Dziewiecki, M.; Emery, S.; Ereditato, A.; Escudero, L.; Finch, A. J.; Floetotto, L.; Friend, M.; Fujii, Y.; Fukuda, Y.; Furmanski, A. P.; Galymov, V.; Giffin, S.; Giganti, C.; Gilje, K.; Goeldi, D.; Golan, T.; Gomez-Cadenas, J. J.; Gonin, M.; Grant, N.; Gudin, D.; Hadley, D. R.; Haesler, A.; Haigh, M. D.; Hamilton, P.; Hansen, D.; Hara, T.; Hartz, M.; Hasegawa, T.; Hastings, N. C.; Hayato, Y.; Hearty, C.; Helmer, R. L.; Hierholzer, M.; Hignight, J.; Hillairet, A.; Himmel, A.; Hiraki, T.; Hirota, S.; Holeczek, J.; Horikawa, S.; Huang, K.; Ichikawa, A. K.; Ieki, K.; Ieva, M.; Ikeda, M.; Imber, J.; Insler, J.; Irvine, T. J.; Ishida, T.; Ishii, T.; Ives, S. J.; Iwai, E.; Iyogi, K.; Izmaylov, A.; Jacob, A.; Jamieson, B.; Johnson, R. A.; Jo, J. H.; Jonsson, P.; Jung, C. K.; Kabirnezhad, M.; Kaboth, A. C.; Kajita, T.; Kakuno, H.; Kameda, J.; Kanazawa, Y.; Karlen, D.; Karpikov, I.; Kearns, E.; Khabibullin, M.; Khotjantsev, A.; Kielczewska, D.; Kikawa, T.; Kilinski, A.; Kim, J.; Kisiel, J.; Kitching, P.; Kobayashi, T.; Koch, L.; Kolaceke, A.; Konaka, A.; Kormos, L. L.; Korzenev, A.; Koseki, K.; Koshio, Y.; Kreslo, I.; Kropp, W.; Kubo, H.; Kudenko, Y.; Kumaratunga, S.; Kurjata, R.; Kutter, T.; Lagoda, J.; Laihem, K.; Lamont, I.; Larkin, E.; Laveder, M.; Lawe, M.; Lazos, M.; Lee, K. P.; Lindner, T.; Lister, C.; Litchfield, R. P.; Longhin, A.; Ludovici, L.; Macaire, M.; Magaletti, L.; Mahn, K.; Malek, M.; Manly, S.; Marino, A. D.; Marteau, J.; Martin, J. F.; Maruyama, T.; Marzec, J.; Mathie, E. L.; Matveev, V.; Mavrokoridis, K.; Mazzucato, E.; McCarthy, M.; McCauley, N.; McFarland, K. S.; McGrew, C.; Metelko, C.; Mezzetto, M.; Mijakowski, P.; Miller, C. A.; Minamino, A.; Mineev, O.; Mine, S.; Missert, A.; Miura, M.; Monfregola, L.; Moriyama, S.; Mueller, Th. A.; Murakami, A.; Murdoch, M.; Murphy, S.; Myslik, J.; Nagasaki, T.; Nakadaira, T.; Nakahata, M.; Nakai, T.; Nakamura, K.; Nakayama, S.; Nakaya, T.; Nakayoshi, K.; Naples, D.; Nielsen, C.; Nirkko, M.; Nishikawa, K.; Nishimura, Y.; O'Keeffe, H. M.; Ohta, R.; Okumura, K.; Okusawa, T.; Oryszczak, W.; Oser, S. M.; Owen, R. A.; Oyama, Y.; Palladino, V.; Palomino, J.; Paolone, V.; Payne, D.; Perevozchikov, O.; Perkin, J. D.; Petrov, Y.; Pickard, L.; Pinzon Guerra, E. S.; Pistillo, C.; Plonski, P.; Poplawska, E.; Popov, B.; Posiadala, M.; Poutissou, J.-M.; Poutissou, R.; Przewlocki, P.; Quilain, B.; Radicioni, E.; Ratoff, P. N.; Ravonel, M.; Rayner, M. A. M.; Redij, A.; Reeves, M.; Reinherz-Aronis, E.; Retiere, F.; Robert, A.; Rodrigues, P. A.; Rojas, P.; Rondio, E.; Roth, S.; Rubbia, A.; Ruterbories, D.; Sacco, R.; Sakashita, K.; Sánchez, F.; Sato, F.; Scantamburlo, E.; Scholberg, K.; Schoppmann, S.; Schwehr, J.; Scott, M.; Seiya, Y.; Sekiguchi, T.; Sekiya, H.; Sgalaberna, D.; Shiozawa, M.; Short, S.; Shustrov, Y.; Sinclair, P.; Smith, B.; Smith, R. J.; Smy, M.; Sobczyk, J. T.; Sobel, H.; Sorel, M.; Southwell, L.; Stamoulis, P.; Steinmann, J.; Still, B.; Suda, Y.; Suzuki, A.; Suzuki, K.; Suzuki, S. Y.; Suzuki, Y.; Szeglowski, T.; Tacik, R.; Tada, M.; Takahashi, S.; Takeda, A.; Takeuchi, Y.; Tanaka, H. K.; Tanaka, H. A.; Tanaka, M. M.; Terhorst, D.; Terri, R.; Thompson, L. F.; Thorley, A.; Tobayama, S.; Toki, W.; Tomura, T.; Totsuka, Y.; Touramanis, C.; Tsukamoto, T.; Tzanov, M.; Uchida, Y.; Ueno, K.; Vacheret, A.; Vagins, M.; Vasseur, G.; Wachala, T.; Waldron, A. V.; Walter, C. W.; Wark, D.; Wascko, M. O.; Weber, A.; Wendell, R.; Wilkes, R. J.; Wilking, M. J.; Wilkinson, C.; Williamson, Z.; Wilson, J. R.; Wilson, R. J.; Wongjirad, T.; Yamada, Y.; Yamamoto, K.; Yanagisawa, C.; Yen, S.; Yershov, N.; Yokoyama, M.; Yuan, T.; Yu, M.; Zalewska, A.; Zalipska, J.; Zambelli, L.; Zaremba, K.; Ziembicki, M.; Zimmerman, E. D.; Zito, M.; Żmuda, J.; T2K Collaboration

    2014-05-01

    The T2K experiment has reported the first observation of the appearance of electron neutrinos in a muon neutrino beam. The main and irreducible background to the appearance signal comes from the presence in the neutrino beam of a small intrinsic component of electron neutrinos originating from muon and kaon decays. In T2K, this component is expected to represent 1.2% of the total neutrino flux. A measurement of this component using the near detector (ND280), located 280 m from the target, is presented. The charged current interactions of electron neutrinos are selected by combining the particle identification capabilities of both the time projection chambers and electromagnetic calorimeters of ND280. The measured ratio between the observed electron neutrino beam component and the prediction is 1.01±0.10 providing a direct confirmation of the neutrino fluxes and neutrino cross section modeling used for T2K neutrino oscillation analyses. Electron neutrinos coming from muons and kaons decay are also separately measured, resulting in a ratio with respect to the prediction of 0.68±0.30 and 1.10±0.14, respectively.

  1. Space radiation shielding studies for astronaut and electronic component risk assessment

    NASA Astrophysics Data System (ADS)

    Fuchs, Jordan; Gersey, Brad; Wilkins, Richard

    The space radiation environment is comprised of a complex and variable mix of high energy charged particles, gamma rays and other exotic species. Elements of this radiation field may also interact with intervening matter (such as a spaceship wall) and create secondary radiation particles such as neutrons. Some of the components of the space radiation environment are highly penetrating and can cause adverse effects in humans and electronic components aboard spacecraft. Developing and testing materials capable of providing effective shielding against the space radiation environment presents special challenges to researchers. Researchers at the Cen-ter for Radiation Engineering and Science for Space Exploration (CRESSE) at Prairie View AM University (PVAMU) perform accelerator based experiments testing the effectiveness of various materials for use as space radiation shields. These experiments take place at the NASA Space Radiation Laboratory at Brookhaven National Laboratory, the proton synchrotron at Loma Linda University Medical Center, and the Los Alamos Neutron Science Center at Los Alamos National Laboratory where charged particles and neutrons are produced at energies similar to those found in the space radiation environment. The work presented in this paper constitutes the beginning phase of an undergraduate research project created to contribute to this ongoing space radiation shielding project. Specifically, this student project entails devel-oping and maintaining a database of information concerning the historical data from shielding experiments along with a systematic categorization and storage system for the actual shielding materials. The shielding materials referred to here range in composition from standard materi-als such as high density polyethylene and aluminum to exotic multifunctional materials such as spectra-fiber infused composites. The categorization process for each material includes deter-mination of the density thickness of individual

  2. Electronic spectra of DyF studied by four-component relativistic configuration interaction methods

    SciTech Connect

    Yamamoto, Shigeyoshi; Tatewaki, Hiroshi

    2015-03-07

    The electronic states of the DyF molecule below 3.0 eV are studied using 4-component relativistic CI methods. Spinors generated by the average-of-configuration Hartree-Fock method with the Dirac-Coulomb Hamiltonian were used in CI calculations by the KRCI (Kramers-restricted configuration interaction) program. The CI reference space was generated by distributing 11 electrons among the 11 Kramers pairs composed mainly of Dy [4f], [6s], [6p] atomic spinors, and double excitations are allowed from this space to the virtual molecular spinors. The CI calculations indicate that the ground state has the dominant configuration (4f{sup 9})(6s{sup 2})(Ω = 7.5). Above this ground state, 4 low-lying excited states (Ω = 8.5, 7.5, 7.5, 7.5) are found with dominant configurations (4f{sup 10})(6s). These results are consistent with the experimental studies of McCarthy et al. Above these 5 states, 2 states were observed at T{sub 0} = 2.39 eV, 2.52 eV by McCarthy et al. and were named as [19.3]8.5 and [20.3]8.5. McCarthy et al. proposed that both states have dominant configurations (4f{sup 9})(6s)(6p), but these configurations are not consistent with the large R{sub e}’s (∼3.9 a.u.) estimated from the observed rotational constants. The present CI calculations provide near-degenerate states of (4f{sup 10})(6p{sub 3/2,1/2}), (4f{sup 10})(6p{sub 3/2,3/2}), and (4f{sup 9})(6s)(6p{sub 3/2,1/2}) at around 3 eV. The former two states have larger R{sub e} (3.88 a.u.) than the third, so that it is reasonable to assign (4f{sup 10})(6p{sub 3/2,1/2}) to [19.3]8.5 and (4f{sup 10})(6p{sub 3/2,3/2}) to [20.3]8.5.

  3. 78 FR 56245 - Certain Wireless Consumer Electronics Devices and Components Thereof; Notice of Request for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-12

    ... Corporation of Kyoto, Japan; Kyocera Communications, Inc. of San Diego, California; LG Electronics, Inc. of Seoul, Korea; LG Electronics U.S.A., Inc. of Englewood Cliffs, New Jersey; Nintendo Co. Ltd. of...

  4. Disassembly and physical separation of electric/electronic components layered in printed circuit boards (PCB).

    PubMed

    Lee, Jaeryeong; Kim, Youngjin; Lee, Jae-chun

    2012-11-30

    Although printed circuit boards (PCBs) contain various elements, only the major elements (i.e., those with content levels in wt% or over grade) of and precious metals (e.g., Ag, Au, and platinum groups) contained within PCBs can be recycled. To recover other elements from PCBs, the PCBs should be properly disassembled as the first step of the recycling process. The recovery of these other elements would be beneficial for efforts to conserve scarce resources, reuse electric/electronic components (EECs), and eliminate environmental problems. This paper examines the disassembly of EECs from wasted PCBs (WPCBs) and the physical separation of these EECs using a self-designed disassembling apparatus and a 3-step separation process of sieving, magnetic separation, and dense medium separation. The disassembling efficiencies were evaluated by using the ratio of grinding area (E(area)) and the weight ratio of the detached EECs (E(weight)). In the disassembly treatment, these efficiencies were improved with an increase of grinder speed and grinder height. 97.7% (E(area)) and 98% (E(weight)) could be accomplished ultimately by 3 repetitive treatments at a grinder speed of 5500 rpm and a grinder height of 1.5mm. Through a series of physical separations, most groups of the EECs (except for the diode, transistor, and IC chip groups) could be sorted at a relatively high separation efficiency of about 75% or more. To evaluate the separation efficiency with regard to the elemental composition, the distribution ratio (R(dis)) and the concentration ratio (R(conc)) were used. 15 elements could be separated with the highest R(dis) and R(conc) in the same separated division. This result implies that the recyclability of the elements is highly feasible, even though the initial content in EECs is lower than several tens of mg/kg.

  5. Growth of iron(III)-reducing bacteria on clay minerals as the sole electron acceptor and comparison of growth yields on a variety of oxidized iron forms.

    PubMed

    Kostka, Joel E; Dalton, Dava D; Skelton, Hayley; Dollhopf, Sherry; Stucki, Joseph W

    2002-12-01

    Smectite clay minerals are abundant in soils and sediments worldwide and are typically rich in Fe. While recent investigations have shown that the structural Fe(III) bound in clay minerals is reduced by microorganisms, previous studies have not tested growth with clay minerals as the sole electron acceptor. Here we have demonstrated that a pure culture of Shewanella oneidensis strain MR-1 as well as enrichment cultures of Fe(III)-reducing bacteria from rice paddy soil and subsurface sediments are capable of conserving energy for growth with the structural Fe(III) bound in smectite clay as the sole electron acceptor. Pure cultures of S. oneidensis were used for more detailed growth rate and yield experiments on various solid- and soluble-phase electron acceptors [smectite, Fe(III) oxyhydroxide FeOOH, Fe(III) citrate, and oxygen] in the same minimal medium. Growth was assessed as direct cell counts or as an increase in cell carbon (measured as particulate organic carbon). Cell counts showed that similar growth of S. oneidensis (10(8) cells ml(-1)) occurred with smectitic Fe(III) and on other Fe forms [amorphous Fe(III) oxyhydroxide, and Fe citrate] or oxygen as the electron acceptor. In contrast, cell yields of S. oneidensis measured as the increase in cell carbon were similar on all Fe forms tested while yields on oxygen were five times higher, in agreement with thermodynamic predictions. Over a range of particle loadings (0.5 to 4 g liter(-1)), the increase in cell number was highly correlated to the amount of structural Fe in smectite reduced. From phylogenetic analysis of the complete 16S rRNA gene sequences, a predominance of clones retrieved from the clay mineral-reducing enrichment cultures were most closely related to the low-G+C gram-positive members of the Bacteria (Clostridium and Desulfitobacterium) and the delta-Proteobacteria (members of the Geobacteraceae). Results indicate that growth with smectitic Fe(III) is similar in magnitude to that with Fe

  6. Separation between Allowed and Forbidden Component of the He I 447 nm Line in High Electron Density Plasma

    SciTech Connect

    Ivkovic, M.; Jovicevic, S.; Konjevic, N.; Gonzalez, M. A.; Gigosos, M. A.

    2008-10-22

    Stark broadened He I 447.1 nm line is measured and the dependence of the separation between its allowed and forbidden components upon electron density is analyzed. Experimental results are compared with computer simulation results and with former experimental results.

  7. 32 CFR 21.565 - Must DoD Components' electronic systems accept Data Universal Numbering System (DUNS) numbers?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 1 2012-07-01 2012-07-01 false Must DoD Components' electronic systems accept Data Universal Numbering System (DUNS) numbers? 21.565 Section 21.565 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE DoD GRANT AND AGREEMENT REGULATIONS DoD GRANTS AND AGREEMENTS-GENERAL MATTERS Information Reporting...

  8. Slowly moving test charge in two-electron component non-Maxwellian plasma

    SciTech Connect

    Ali, S.; Eliasson, B.

    2015-08-15

    Potential distributions around a slowly moving test charge are calculated by taking into account the electron-acoustic waves in an unmagnetized plasma. Considering a neutralizing background of static positive ions, the supra-thermal hot and cold electrons are described by the Vlasov equations to account for the Kappa (power-law in velocity space) and Maxwell equilibrium distributions. Fourier analysis further leads to the derivation of electrostatic potential showing the impact of supra-thermal hot electrons. The test charge moves slowly in comparison with the hot and cold electron thermal speeds and is therefore shielded by the electrons. This gives rise to a short-range Debye-Hückel potential decaying exponentially with distance and to a far field potential decaying as inverse third power of the distance from the test charge. The results are relevant for both laboratory and space plasmas, where supra-thermal hot electrons with power-law distributions have been observed.

  9. Single-Particle Cryo-EM and 3D Reconstruction of Hybrid Nanoparticles with Electron-Dense Components.

    PubMed

    Yu, Guimei; Yan, Rui; Zhang, Chuan; Mao, Chengde; Jiang, Wen

    2015-10-01

    Single-particle cryo-electron microscopy (cryo-EM), accompanied with 3D reconstruction, is a broadly applicable tool for the structural characterization of macromolecules and nanoparticles. Recently, the cryo-EM field has pushed the limits of this technique to higher resolutions and samples of smaller molecular mass, however, some samples still present hurdles to this technique. Hybrid particles with electron-dense components, which have been studied using single-particle cryo-EM yet with limited success in 3D reconstruction due to the interference caused by electron-dense elements, constitute one group of such challenging samples. To process such hybrid particles, a masking method is developed in this work to adaptively remove pixels arising from electron-dense portions in individual projection images while maintaining maximal biomass signals for subsequent 2D alignment, 3D reconstruction, and iterative refinements. As demonstrated by the success in 3D reconstruction of an octahedron DNA/gold hybrid particle, which has been previously published without a 3D reconstruction, the devised strategy that combines adaptive masking and standard single-particle 3D reconstruction approach has overcome the hurdle of electron-dense elements interference, and is generally applicable to cryo-EM structural characterization of most, if not all, hybrid nanomaterials with electron-dense components.

  10. 76 FR 12994 - In the Matter of Certain Digital Televisions and Components Thereof, and Certain Electronic...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-09

    ... February 4, 2011, under section 337 of the Tariff Act of 1930, as amended, 19 U.S.C. 1337, on behalf of LG... 1930, as amended, 19 U.S.C. 1337, on behalf of LG Electronics, Inc. The complaint alleges violations of...: LG Electronics, Inc., LG Twin Towers, 20, Yeouido-dong, Yeongdeungpo-gu, Seoul 150-721, Korea....

  11. Radial Profiles of Electron Density and Current Components at Cathode Surface in LaB6 Hollow Cathode Arc

    NASA Astrophysics Data System (ADS)

    Suzuki, Setsuo; Asano, Toshiaki; Morimiya, Osami

    1987-06-01

    Experimental studies on a hydrogen-fed LaB6 hollow cathode arc have been pursued. The plasma parameter in the cathode has been measured by a Langmuir probe. The radial variation in the electron density inside the cathode was calculated using the continuity and momentum equations, showing good agreement with the experimental results. The electron density at the cathode surface was estimated to be 15%-20% of that at the cathode axis. It was also found from the current balance that the arc current components at the cathode surface consist of a thermionic current which takes into account the Schottky effect, the ion current and the secondary electron current induced by ion bombardment. The ion current and the cathode surface is larger than the electron current emitted from the cathode.

  12. Component-Level Electronic-Assembly Repair (CLEAR) Spacecraft Circuit Diagnostics by Analog and Complex Signature Analysis

    NASA Technical Reports Server (NTRS)

    Oeftering, Richard C.; Wade, Raymond P.; Izadnegahdar, Alain

    2011-01-01

    The Component-Level Electronic-Assembly Repair (CLEAR) project at the NASA Glenn Research Center is aimed at developing technologies that will enable space-flight crews to perform in situ component-level repair of electronics on Moon and Mars outposts, where there is no existing infrastructure for logistics spares. These technologies must provide effective repair capabilities yet meet the payload and operational constraints of space facilities. Effective repair depends on a diagnostic capability that is versatile but easy to use by crew members that have limited training in electronics. CLEAR studied two techniques that involve extensive precharacterization of "known good" circuits to produce graphical signatures that provide an easy-to-use comparison method to quickly identify faulty components. Analog Signature Analysis (ASA) allows relatively rapid diagnostics of complex electronics by technicians with limited experience. Because of frequency limits and the growing dependence on broadband technologies, ASA must be augmented with other capabilities. To meet this challenge while preserving ease of use, CLEAR proposed an alternative called Complex Signature Analysis (CSA). Tests of ASA and CSA were used to compare capabilities and to determine if the techniques provided an overlapping or complementary capability. The results showed that the methods are complementary.

  13. The EPQ Code System for Simulating the Thermal Response of Plasma-Facing Components to High-Energy Electron Impact

    SciTech Connect

    Ward, Robert Cameron; Steiner, Don

    2004-06-15

    The generation of runaway electrons during a thermal plasma disruption is a concern for the safe and economical operation of a tokamak power system. Runaway electrons have high energy, 10 to 300 MeV, and may potentially cause extensive damage to plasma-facing components (PFCs) through large temperature increases, melting of metallic components, surface erosion, and possible burnout of coolant tubes. The EPQ code system was developed to simulate the thermal response of PFCs to a runaway electron impact. The EPQ code system consists of several parts: UNIX scripts that control the operation of an electron-photon Monte Carlo code to calculate the interaction of the runaway electrons with the plasma-facing materials; a finite difference code to calculate the thermal response, melting, and surface erosion of the materials; a code to process, scale, transform, and convert the electron Monte Carlo data to volumetric heating rates for use in the thermal code; and several minor and auxiliary codes for the manipulation and postprocessing of the data. The electron-photon Monte Carlo code used was Electron-Gamma-Shower (EGS), developed and maintained by the National Research Center of Canada. The Quick-Therm-Two-Dimensional-Nonlinear (QTTN) thermal code solves the two-dimensional cylindrical modified heat conduction equation using the Quickest third-order accurate and stable explicit finite difference method and is capable of tracking melting or surface erosion. The EPQ code system is validated using a series of analytical solutions and simulations of experiments. The verification of the QTTN thermal code with analytical solutions shows that the code with the Quickest method is better than 99.9% accurate. The benchmarking of the EPQ code system and QTTN versus experiments showed that QTTN's erosion tracking method is accurate within 30% and that EPQ is able to predict the occurrence of melting within the proper time constraints. QTTN and EPQ are verified and validated as able

  14. Estimating the contribution of the authigenic mineral component to the long-term reactive silica accumulation on the western shelf of the Mississippi River Delta

    NASA Astrophysics Data System (ADS)

    Presti, Massimo; Michalopoulos, Panagiotis

    2008-04-01

    Previous studies have shown how biogenic silica particles undergo conversion to aluminosilicate phases in large tropical deltaic systems, thus affecting the world ocean budget of major seawater cations. This study tackles the important question of the silica budget in the coastal zone of the Mississippi River Delta, providing evidence for the role of biogenic silica diagenesis in this subtropical system from direct examination of individual diatom particles, sediment leachates and pore-water composition. The estimated reactive silica stored in the study area (5990 km 2) is based on operational leaches that account for altered biogenic silica particles and other authigenic aluminosilicate phases in addition to fresh biogenic silica. Early diagenesis of silica in the delta front occurs mainly where more siliceous material is deposited. An inner-shelf area, where hypoxic conditions are found, significantly contributes to the formation of authigenic products of Si alteration. Data suggest that the limiting factor of silica alteration processes is the availability of detrital phases such as Al and Fe. The estimated total reactive silica accumulation in the study area is 1.45×10 10 mol Si year -1, representing ˜2.2% of the long-term bulk sediment accumulation. On the basis of a conservative appraisal, the authigenic mineral components account for ˜40% of the long-term reactive silica storage. This study shows that non-tropical deltaic systems are significantly more important sinks of silica than previously thought and that, where conditions are favourable, a consistent portion of reactive silica not leaving the shelf is stored within the delta in the form of authigenic components.

  15. Mass-specific optical absorption coefficients and imaginary part of the complex refractive indices of mineral dust components measured by a multi-wavelength photoacoustic spectrometer

    NASA Astrophysics Data System (ADS)

    Utry, N.; Ajtai, T.; Pintér, M.; Tombácz, E.; Illés, E.; Bozóki, Z.; Szabó, G.

    2015-01-01

    Mass-specific optical absorption coefficients (MACs) and the imaginary part (κ) of the refractive indices of various mineral dust components including silicate clays (illite, kaolin and bentonite), oxides (quartz, hematite and rutile), and carbonate (limestone) were determined at the wavelengths of 1064, 532, 355 and 266 nm. The MAC values were calculated from aerosol optical absorption coefficients measured by a multi-wavelength photoacoustic (PA) instrument, the mass concentration and the number size distribution of the generated aerosol samples as well as the size transfer functions of the measuring instruments. Values of κ were calculated from the measured and particle-loss-corrected data by using a Mie-theory-based retrieval algorithm. The determined values could be used for comparisons with calculated wavelength-dependent κ values typically deduced from bulk-phase measurements by using indirect measurement methods. Accordingly, the presented comparison of the measured and calculated aerosol optical absorption spectra revealed the strong need for standardized sample preparation and measurement methodology in case of bulk-phase measurements.

  16. A new approach to provide high-reliability data systems without using space-qualified electronic components

    NASA Astrophysics Data System (ADS)

    Haebel, Wolfgang

    2004-08-01

    This paper describes the present situation and the expected trends with regard to the availability of electronic components, their quality levels, technology trends and sensitivity to the space environment. Many recognized vendors have already discontinued their MIL production line and state of the art components will in many cases not be offered in this quality level because of the shrinking market. It becomes therefore obvious that new methods need to be considered "How to build reliable Data Systems for space applications without High-Rel parts". One of the most promising approaches is the identification, masking and suppression of faults by developing fault-tolerant computer systems which is described in this paper.

  17. Finite-element-method study of stresses on simulated electronic components encapsulated in polystyrene-bead foam

    SciTech Connect

    Swanson, G.D.

    1981-03-01

    As part of an encapsulant evaluation for a high voltage electronic assembly, the linear elastic finite element method computer code SASL was used to calculate the stress distribution in an axisymmetric solder joint under load. A simulated electronic component in the form of a thumb tack was used as a physical model to calculate lead wire loads when encapsulated in 0.6 g/cm/sup 3/ polystyrene bead form. The calculated lead wire loads disagreed with previous experimental data. Reanalysis of those data revealed nonlinear effects which were not adequately modeled in the SASL calculation.

  18. 76 FR 58841 - Certain Digital Televisions and Components Thereof, and Certain Electronic Devices Having a Blu...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-22

    ... investigation on March 9, 2011, based on complaints filed by LG Electronics, Inc. of Seoul, Korea (``LGE''). 76 FR 12994-5 (Mar. 9, 2011). The complaints allege violations of section 337 of the Tariff Act of...

  19. Stakeholder engagement: a key component of integrating genomic information into electronic health records.

    PubMed

    Hartzler, Andrea; McCarty, Catherine A; Rasmussen, Luke V; Williams, Marc S; Brilliant, Murray; Bowton, Erica A; Clayton, Ellen Wright; Faucett, William A; Ferryman, Kadija; Field, Julie R; Fullerton, Stephanie M; Horowitz, Carol R; Koenig, Barbara A; McCormick, Jennifer B; Ralston, James D; Sanderson, Saskia C; Smith, Maureen E; Trinidad, Susan Brown

    2013-10-01

    Integrating genomic information into clinical care and the electronic health record can facilitate personalized medicine through genetically guided clinical decision support. Stakeholder involvement is critical to the success of these implementation efforts. Prior work on implementation of clinical information systems provides broad guidance to inform effective engagement strategies. We add to this evidence-based recommendations that are specific to issues at the intersection of genomics and the electronic health record. We describe stakeholder engagement strategies employed by the Electronic Medical Records and Genomics Network, a national consortium of US research institutions funded by the National Human Genome Research Institute to develop, disseminate, and apply approaches that combine genomic and electronic health record data. Through select examples drawn from sites of the Electronic Medical Records and Genomics Network, we illustrate a continuum of engagement strategies to inform genomic integration into commercial and homegrown electronic health records across a range of health-care settings. We frame engagement as activities to consult, involve, and partner with key stakeholder groups throughout specific phases of health information technology implementation. Our aim is to provide insights into engagement strategies to guide genomic integration based on our unique network experiences and lessons learned within the broader context of implementation research in biomedical informatics. On the basis of our collective experience, we describe key stakeholder practices, challenges, and considerations for successful genomic integration to support personalized medicine.

  20. Preservation of protein globules and peptidoglycan in the mineralized cell wall of nitrate-reducing, iron(II)-oxidizing bacteria: a cryo-electron microscopy study.

    PubMed

    Miot, J; Maclellan, K; Benzerara, K; Boisset, N

    2011-11-01

    Iron-oxidizing bacteria are important actors of the geochemical cycle of iron in modern environments and may have played a key role all over Earth's history. However, in order to better assess that role on the modern and the past Earth, there is a need for better understanding the mechanisms of bacterial iron oxidation and for defining potential biosignatures to be looked for in the geologic record. In this study, we investigated experimentally and at the nanometre scale the mineralization of iron-oxidizing bacteria with a combination of synchrotron-based scanning transmission X-ray microscopy (STXM), scanning transmission electron microscopy (STEM) and cryo-transmission electron microscopy (cryo-TEM). We show that the use of cryo-TEM instead of conventional microscopy provides detailed information of the successive iron biomineralization stages in anaerobic nitrate-reducing iron-oxidizing bacteria. These results suggest the existence of preferential Fe-binding and Fe-oxidizing sites on the outer face of the plasma membrane leading to the nucleation and growth of Fe minerals within the periplasm of these cells that eventually become completely encrusted. In contrast, the septa of dividing cells remain nonmineralized. In addition, the use of cryo-TEM offers a detailed view of the exceptional preservation of protein globules and the peptidoglycan within the Fe-mineralized cell walls of these bacteria. These organic molecules and ultrastructural details might be protected from further degradation by entrapment in the mineral matrix down to the nanometre scale. This is discussed in the light of previous studies on the properties of Fe-organic interactions and more generally on the fossilization of mineral-organic assemblies.

  1. Some Aspects of the Implementation of Double Group Symmetry and Electron Correlation in Molecular 4-Component Calculations

    NASA Technical Reports Server (NTRS)

    Dyall, Kenneth G.; Arnold, James O. (Technical Monitor)

    1994-01-01

    The efficient implementation of method for electron correlation in molecular 4-component calculations demands that symmetry be exploited where possible. Algorithms for the construction of matrices and the transformation of integrals over symmetry-adapted basis functions, where the point group is restricted to D(sub 2h) and subgroups, will be presented. The merits of keeping the primitive integrals in the scalar basis will be compared with those of transforming them to the 2-spinor basis.

  2. First principles study on the electronic structures and stability of Cr 7C 3 type multi-component carbides

    NASA Astrophysics Data System (ADS)

    Xiao, B.; Feng, J.; Zhou, C. T.; Xing, J. D.; Xie, X. J.; Chen, Y. H.

    2008-06-01

    First principles calculations were conducted to investigate the stabilities of six multi-component carbides of Cr 7C 3 by calculating the cohesive energy and formation enthalpy of them. The theoretical predictions were compared with the experimental results and they were in agreement with each other. The electronic structures of the six carbides were also calculated in order to provide more information about the relationship between the stability and crystal compositions at atomic scale.

  3. Ecology and thermal inactivation of microbes in and on interplanetary space vehicle components. [examined with a scanning electron microscope

    NASA Technical Reports Server (NTRS)

    Campbell, J. E.

    1974-01-01

    The uses of scanning electron microscopy in assessing changes that occur in spores exposed to wet and dry heat cycles at elevated temperatures were examined. Several species of Bacillus and other nonspore-forming species of organisms were used for the experiment. Surface morphology of viable and nonviable organisms was clearly detectable by this method, making it a potentially useful technique for investigating microbial inactivation on space vehicle surfaces and components. Micrographs of the spores and bacterial cells are provided.

  4. Dynamics of coupled simplest chaotic two-component electronic circuits and its potential application to random bit generation

    SciTech Connect

    Modeste Nguimdo, Romain; Tchitnga, Robert; Woafo, Paul

    2013-12-15

    We numerically investigate the possibility of using a coupling to increase the complexity in simplest chaotic two-component electronic circuits operating at high frequency. We subsequently show that complex behaviors generated in such coupled systems, together with the post-processing are suitable for generating bit-streams which pass all the NIST tests for randomness. The electronic circuit is built up by unidirectionally coupling three two-component (one active and one passive) oscillators in a ring configuration through resistances. It turns out that, with such a coupling, high chaotic signals can be obtained. By extracting points at fixed interval of 10 ns (corresponding to a bit rate of 100 Mb/s) on such chaotic signals, each point being simultaneously converted in 16-bits (or 8-bits), we find that the binary sequence constructed by including the 10(or 2) least significant bits pass statistical tests of randomness, meaning that bit-streams with random properties can be achieved with an overall bit rate up to 10×100 Mb/s =1Gbit/s (or 2×100 Mb/s =200 Megabit/s). Moreover, by varying the bias voltages, we also investigate the parameter range for which more complex signals can be obtained. Besides being simple to implement, the two-component electronic circuit setup is very cheap as compared to optical and electro-optical systems.

  5. Dynamics of coupled simplest chaotic two-component electronic circuits and its potential application to random bit generation.

    PubMed

    Nguimdo, Romain Modeste; Tchitnga, Robert; Woafo, Paul

    2013-12-01

    We numerically investigate the possibility of using a coupling to increase the complexity in simplest chaotic two-component electronic circuits operating at high frequency. We subsequently show that complex behaviors generated in such coupled systems, together with the post-processing are suitable for generating bit-streams which pass all the NIST tests for randomness. The electronic circuit is built up by unidirectionally coupling three two-component (one active and one passive) oscillators in a ring configuration through resistances. It turns out that, with such a coupling, high chaotic signals can be obtained. By extracting points at fixed interval of 10 ns (corresponding to a bit rate of 100 Mb/s) on such chaotic signals, each point being simultaneously converted in 16-bits (or 8-bits), we find that the binary sequence constructed by including the 10(or 2) least significant bits pass statistical tests of randomness, meaning that bit-streams with random properties can be achieved with an overall bit rate up to 10×100 Mb/s = 1 Gbit/s (or 2×100 Mb/s =200 Megabit/s). Moreover, by varying the bias voltages, we also investigate the parameter range for which more complex signals can be obtained. Besides being simple to implement, the two-component electronic circuit setup is very cheap as compared to optical and electro-optical systems.

  6. Quality of determinations obtained from laboratory reference samples used in the calibration of X-ray electron probe microanalysis of silicate minerals

    NASA Astrophysics Data System (ADS)

    Pavlova, Ludmila A.; Suvorova, Ludmila F.; Belozerova, Olga Yu; Pavlov, Sergey M.

    2003-02-01

    Nine simple minerals and oxides, traditionally used as laboratory reference samples in the electron probe microanalysis (EPMA) of silicate minerals, have been quantitatively evaluated. Three separate series of data, comprising the average concentration, standard deviation, relative standard deviation, confidence interval and the z-score of data quality, were calculated for 21 control samples derived from calibrations obtained from three sets of reference samples: (1) simple minerals; (2) oxides; and (3) certified glass reference materials. No systematic difference was observed between the concentrations obtained from these three calibration sets when analyzed results were compared to certified compositions. The relative standard deviations obtained for each element were smaller than target values for all determinations. The z-score values for all elements determined fell within acceptable limits (-2< z<2) for concentrations ranging from 0.1 to 100%. These experiments show that the quality of data obtained from laboratory reference calibration samples is not inferior to that from certified reference glasses. The quality of results obtained corresponds to the 'applied geochemistry' type of analysis (category 2) as defined in the GeoPT proficiency testing program. Therefore, the laboratory reference samples can be used for calibrating EPMA techniques in the analysis of silicate minerals and for controlling the quality of results.

  7. Electronic structure calculations of mercury mobilization from mineral phases and photocatalytic removal from water and the atmosphere.

    PubMed

    Da Pieve, Fabiana; Stankowski, Martin; Hogan, Conor

    2014-09-15

    Mercury is a hazardous environmental pollutant mobilized from natural sources, and anthropogenically contaminated and disturbed areas. Current methods to assess mobility and environmental impact are mainly based on field measurements, soil monitoring, and kinetic modelling. In order to understand in detail the extent to which different mineral sources can give rise to mercury release it is necessary to investigate the complexity at the microscopic level and the possible degradation/dissolution processes. In this work, we investigated the potential for mobilization of mercury structurally trapped in three relevant minerals occurring in hot spring environments and mining areas, namely, cinnabar (α-HgS), corderoite (α-Hg3S2Cl2), and mercuric chloride (HgCl2). Quantum chemical methods based on density functional theory as well as more sophisticated approaches are used to assess the possibility of a) direct photoreduction and formation of elemental Hg at the surface of the minerals, providing a path for ready release in the environment; and b) reductive dissolution of the minerals in the presence of solutions containing halogens. Furthermore, we study the use of TiO2 as a potential photocatalyst for decontamination of polluted waters (mainly Hg(2+)-containing species) and air (atmospheric Hg(0)). Our results partially explain the observed pathways of Hg mobilization from relevant minerals and the microscopic mechanisms behind photocatalytic removal of Hg-based pollutants. Possible sources of disagreement with observations are discussed and further improvements to our approach are suggested.

  8. Electronic Components, Transducers, and Basic Circuits. A Study Guide of the Science and Engineering Technician Curriculum.

    ERIC Educational Resources Information Center

    Mowery, Donald R.

    This study guide is part of a program of studies entitled the Science and Engineering Technician (SET) Curriculum developed for the purpose of training technicians in the use of electronic instruments and their applications. The program integrates elements from the disciplines of chemistry, physics, mathematics, mechanical technology, and…

  9. Correlation of redox levels of component electron carriers with total electron flux in an electron-transport system. P-700 and the photoreduction of NADP+ in chloroplast fragments.

    PubMed

    Hiyama, T; McSwain, B D; Arnon, D I

    1977-04-11

    A mathematical analysis is described which measures the effects of actinic light intensity and concentration of an artificial electron donor on the steady-state light-induced redox level of a reaction-center pigment (e.g. P-700) and on the overall light-induced electron flux (e.g. reduction of NADP+). The analysis led to a formulation (somewhat similar to the Michaelis-Menten equation for enzyme kinetics) in which a parameter, I1/2, is defined as the actinic light intensity that, at a given concentration of electron donro, renders the reaction-center pigment half oxidized and half reduced. To determine the role of a presumed reaction-center pigment, I1/2 is compared with another parameter, equivalent to I1/2, that is obtained independently of the reaciton-center pigment by measuring the effect of actinic light intensity and concentration of electron donor on the overall electron flow. The theory was tested and validated in a model system with spinach Photosystem I chloroplast fragments by measurements of photooxidation of P-700 and light-induced reduction of NADP+ by reduced 2,6-dichlorophenolindophenol. A possible extension of this mathematical analysis to more general electron-transport systems is discussed.

  10. In-situ formation of multiphase electron beam physical vapor deposited barrier coatings for turbine components

    DOEpatents

    Subramanian, Ramesh

    2001-01-01

    A turbine component (10), such as a turbine blade, is provided which is made of a metal alloy (22) and a base columnar thermal barrier coating (20) on the alloy surface, where a heat resistant ceramic oxide sheath material (32' or 34') covers the columns (28), and the sheath material is the reaction product of a precursor ceramic oxide sheath material and the base thermal barrier coating material.

  11. Modeling the effects of low-LET cosmic rays on electronic components.

    PubMed

    Keating, A; Goncalves, P; Pimenta, M; Brogueira, P; Zadeh, A; Daly, E

    2012-08-01

    The effects of cosmic radiation in single cells, organic tissues and electronics are a major concern for space exploration and manned missions. Standard heavy ions radiation tests employ ion cocktails with energy of the order of 10 MeV per nucleon and with a linear energy transfer ranging from a few MeV cm(2) mg(-1) to hundreds of MeV cm(2) mg(-1). In space, cosmic rays show significant fluxes at energies up to the order of GeV per nucleon. The present work aims at investigating single event damage due to low-, high- and very-high-energy ions. The European Space Agency reference single event upset monitor data are used to support the discussion. Finally, the effect of ionization induced directly by primary particles and ionization induced by recoils produced in an electronic device is investigated for different types of devices.

  12. Optical Coating Performance for Heat Reflectors of the JWST-ISIM Electronic Component

    NASA Technical Reports Server (NTRS)

    Rashford, Robert A.; Perrygo, Charles M.; Garrison, Matthew B.; White, Bryant K.; Threat, Felix T.; Quijada, Manuel A.; Jeans, James W.; Huber, Frank K.; Bousquet, Robert R.; Shaw, Dave

    2011-01-01

    A document discusses a thermal radiator design consisting of lightweight composite materials and low-emittance metal coatings for use on the James Webb Space Telescope (JWST) structure. The structure will have a Thermal Subsystem unit to provide passive cooling to the Integrated Science Instrument Module (ISIM) control electronics. The ISIM, in the JWST observatory, is the platform that provides the mounting surfaces for the instrument control electronics. Dissipating the control electronic generated-heat away from JWST is of paramount importance so that the spacecraft s own heat does not interfere with the infrared-light gathering of distant cosmic sources. The need to have lateral control in the emission direction of the IEC (ISIM Electronics Compartment) radiators led to the development of a directional baffle design that uses multiple curved mirrorlike surfaces. This concept started out from the so-called Winston non-imaging optical concentrators that use opposing parabolic reflector surfaces, where each parabola has its focus at the opposite edge of the exit aperture. For this reason they are often known as compound parabolic concentrators or CPCs. This radiator system with the circular section was chosen for the IEC reflectors because it offers two advantages over other designs. The first is that the area of the reflector strips for a given radiator area is less, which results in a lower mass baffle assembly. Secondly, the fraction of energy emitted by the radiator strips and subsequently reflected by the baffle is less. These fewer reflections reduced the amount of energy that is absorbed and eventually re-emitted, typically in a direction outside the design emission range angle. A baffle frame holds the mirrors in position above a radiator panel on the IEC. Together, these will direct the majority of the heat from the IEC above the sunshield away towards empty space.

  13. Degradation of Silicone Oils Exposed to Geostationary Environment Components: Ultraviolet Radiations and Electron Flux

    NASA Astrophysics Data System (ADS)

    Jochem, H.; Rejsek-Riba, V.; Maerten, E.; Baceiredo, A.; Remaury, S.

    Degradation of polydimethylsiloxane and vinyl-terminated polydimethylsiloxane oils exposed to UV radiation or 1.25 MeV electron flux was investigated using EPR, GC Headspace, NMR, GPC and UV-vis-NIR spectroscopy. To examine the influence of synthetic method, these two oils were prepared by ring opening polymerization using either an inorganic initiator KOH or an organic catalyst N-Heterocyclic carbene. Under UV radiation, any chemical change is observed for polydimethylsiloxane, whereas vinyl-terminated polydimethylsiloxane presents a decrease of vinyl functions and an increase of chain length. Both polydimethylsiloxane and vinyl terminated polydimethylsiloxane demonstrated a degradation of thermo-optical properties, more significant for oils synthesized with organic catalyst. By improving oil purification, the degradation of thermo-optical properties can be reduced. Effects of electron flux are similar for each oil, thus independently of synthetic method and end functions. Electron flux generates important chemical damages initiated by homolytic chain scissions. Radical recombination produces gases (methane and ethane), new functions (Si-H) and bonds across silicone chains leading to a solid state material. Crosslinking of chains occurs by formation of R-Si-(O)3 and Si-CH2-Si groups. Silyl radicals are trapped in the polymer network and can be detected even 1 week after the end of irradiation.

  14. Homologous electron transport components fail to increase fatty acid hydroxylation in transgenic Arabidopsis thaliana.

    PubMed

    Wayne, Laura L; Browse, John

    2013-01-01

    Ricinoleic acid, a hydroxylated fatty acid (HFA) present in castor ( Ricinus communis) seeds, is an important industrial commodity used in products ranging from inks and paints to polymers and fuels. However, due to the deadly toxin ricin and allergens also present in castor, it would be advantageous to produce ricinoleic acid in a different agricultural crop. Unfortunately, repeated efforts at heterologous expression of the castor fatty acid hydroxylase (RcFAH12) in the model plant Arabidopsis thaliana have produced only 17-19% HFA in the seed triacylglycerols (TAG), whereas castor seeds accumulate up to 90% ricinoleic acid in the endosperm TAG. RcFAH12 requires an electron supply from NADH:cytochrome b5 reductase (CBR1) and cytochrome b5 (Cb5) to synthesize ricinoleic acid. Previously, our laboratory found a mutation in the Arabidopsis CBR1 gene, cbr1-1, that caused an 85% decrease in HFA levels in the RcFAH12 Arabidopsis line. These results raise the possibility that electron supply to the heterologous RcFAH12 may limit the production of HFA. Therefore, we hypothesized that by heterologously expressing RcCb5, the reductant supply to RcFAH12 would be improved and lead to increased HFA accumulation in Arabidopsis seeds. Contrary to this proposal, heterologous expression of the top three RcCb5 candidates did not increase HFA accumulation. Furthermore, coexpression of RcCBR1 and RcCb5 in RcFAH12 Arabidopsis also did not increase in HFA levels compared to the parental lines. These results demonstrate that the Arabidopsis electron transfer system is supplying sufficient reductant to RcFAH12 and that there must be other bottlenecks limiting the accumulation of HFA.

  15. The electron temperature and optical emission structure of the central component of CTB 80

    NASA Technical Reports Server (NTRS)

    Blair, William P.; Fesen, Robert A.; Becker, Robert H.

    1988-01-01

    Optical spectra on the central component of the galactic supernova remnant CTB 80 are presented. Long slit CCD spectra reveal relative line-intensity variations among individual filaments, the presence of Balmer-dominated emission in the core's east and west optical lobes, and no radial velocities in excess of 300 km/s. Aperture spectrophotometry of the temperature-sensitive forbiddden O III lines suggests Te = 25,000 K, thus favoring a shock-heated interpretation for the remnant's optical core emission. These results indicate that fundamental differences exist betweem the optical emission of CTB 80's central core component and the Crab Nebula, despite similarities in these remnants' radio and X-ray properties. The optical emission from CTB 80's core is likely to be a direct result of the interaction of an active pulsar with its adjacent partially neutral interstellar medium. The size of CTB 80's outer structure and the absence of either high velocity or enhanced abundances in the region local to CTB 80's pulsar argue for a considerably larger age for CTB 80 than the Crab Nebula's 1000 yr. A qualitative picture for CTB 80 that can plausibly explain many of the core's properties is proposed.

  16. Quantum diffraction and shielding effects on the low-energy electron-ion bremsstrahlung in two-component semiclassical plasmas

    SciTech Connect

    Lee, Myoung-Jae; Jung, Young-Dae

    2015-10-15

    The quantum diffraction and shielding effects on the low-energy bremsstrahlung process are investigated in two-component semiclassical plasmas. The impact-parameter analysis with the micropotential taking into account the quantum diffraction and shielding effects is employed to obtain the electron-ion bremsstrahlung radiation cross section as a function of the de Broglie wavelength, density parameter, impact parameter, photon energy, and projectile energy. The result shows that the influence of quantum diffraction and shielding strongly suppresses the bremsstrahlung radiation spectrum in semiclassical plasmas. It is found that the quantum diffraction and shielding effects have broaden the photon emission domain. It is also found that the photon emission domain is almost independent of the radiation photon energy. In addition, it is found that the influence of quantum diffraction and shielding on the bremsstrahlung spectrum decreases with an increase of the projectile energy. The density effect on the electron-ion bremsstrahlung cross section is also discussed.

  17. Ion-acoustic double layers in a five component cometary plasma with kappa described electrons and ions

    NASA Astrophysics Data System (ADS)

    Michael, Manesh; Venugopal, C.; Sreekala, G.; Willington, Neethu Theresa; Sebastian, Sijo

    2016-07-01

    We investigate the propagation characteristics of Ion-acoustic solitons and double layers in a five component cometary plasma consisting of positively and negatively charged oxygen ions, kappa described hydrogen ions, hot solar electrons, and slightly colder cometary electrons. The KdV and modified KdV equations are derived for the system and its solution is plotted for different kappa values and negatively charged oxygen ion densities. It is found that the strength of double layer increases with increasing spectral indices. It, however, decreases with increasing negatively charged oxygen ion densities. The parameter for the transition from compressive to rarefactive soliton is also specified. The presence of negatively charged oxygen ions can significantly affect the nonlinearity coefficients (both quadratic and cubic) of a double layer.

  18. Enantiomer-specific analysis of multi-component mixtures by correlated electron imaging-ion mass spectrometry

    NASA Astrophysics Data System (ADS)

    Fanood, Mohammad M. Rafiee; Ram, N. Bhargava; Lehmann, C. Stefan; Powis, Ivan; Janssen, Maurice H. M.

    2015-06-01

    Simultaneous, enantiomer-specific identification of chiral molecules in multi-component mixtures is extremely challenging. Many established techniques for single-component analysis fail to provide selectivity in multi-component mixtures and lack sensitivity for dilute samples. Here we show how enantiomers may be differentiated by mass-selected photoelectron circular dichroism using an electron-ion coincidence imaging spectrometer. As proof of concept, vapours containing ~1% of two chiral monoterpene molecules, limonene and camphor, are irradiated by a circularly polarized femtosecond laser, resulting in multiphoton near-threshold ionization with little molecular fragmentation. Large chiral asymmetries (2-4%) are observed in the mass-tagged photoelectron angular distributions. These asymmetries switch sign according to the handedness (R- or S-) of the enantiomer in the mixture and scale with enantiomeric excess of a component. The results demonstrate that mass spectrometric identification of mixtures of chiral molecules and quantitative determination of enantiomeric excess can be achieved in a table-top instrument.

  19. Electronic Nose Based on Independent Component Analysis Combined with Partial Least Squares and Artificial Neural Networks for Wine Prediction

    PubMed Central

    Aguilera, Teodoro; Lozano, Jesús; Paredes, José A.; Álvarez, Fernando J.; Suárez, José I.

    2012-01-01

    The aim of this work is to propose an alternative way for wine classification and prediction based on an electronic nose (e-nose) combined with Independent Component Analysis (ICA) as a dimensionality reduction technique, Partial Least Squares (PLS) to predict sensorial descriptors and Artificial Neural Networks (ANNs) for classification purpose. A total of 26 wines from different regions, varieties and elaboration processes have been analyzed with an e-nose and tasted by a sensory panel. Successful results have been obtained in most cases for prediction and classification. PMID:22969387

  20. Directed self-assembly of mesoscopic electronic components into sparse arrays with controlled orientation using diamagnetic levitation

    NASA Astrophysics Data System (ADS)

    Tkachenko, Anton; Lu, James J.-Q.

    2015-07-01

    This paper presents a directed self-assembly (DSA) approach for assembling small electronic components, such as semiconductor dies, into sparse 2D arrays using diamagnetic levitation. The dies attached to a diamagnetic layer can be levitated at a room temperature over a stage made of magnets arranged in a checkerboard pattern. By selecting a proper die design, levitation height, and vibration pattern of the magnetic stage we assemble the dies into a regular 2D array with a specific lateral and vertical orientation of the dies. The assembled dies are transferred to a receiving substrate using capillary force.

  1. Efficient and Accurate Identification of Platinum-Group Minerals by a Combination of Mineral Liberation and Electron Probe Microanalysis with a New Approach to the Offline Overlap Correction of Platinum-Group Element Concentrations.

    PubMed

    Osbahr, Inga; Krause, Joachim; Bachmann, Kai; Gutzmer, Jens

    2015-10-01

    Identification and accurate characterization of platinum-group minerals (PGMs) is usually a very cumbersome procedure due to their small grain size (typically below 10 µm) and inconspicuous appearance under reflected light. A novel strategy for finding PGMs and quantifying their composition was developed. It combines a mineral liberation analyzer (MLA), a point logging system, and electron probe microanalysis (EPMA). As a first step, the PGMs are identified using the MLA. Grains identified as PGMs are then marked and coordinates recorded and transferred to the EPMA. Case studies illustrate that the combination of MLA, point logging, and EPMA results in the identification of a significantly higher number of PGM grains than reflected light microscopy. Analysis of PGMs by EPMA requires considerable effort due to the often significant overlaps between the X-ray spectra of almost all platinum-group and associated elements. X-ray lines suitable for quantitative analysis need to be carefully selected. As peak overlaps cannot be avoided completely, an offline overlap correction based on weight proportions has been developed. Results obtained with the procedure proposed in this study attain acceptable totals and atomic proportions, indicating that the applied corrections are appropriate.

  2. Pb-free surface-finishing on electronic components' terminals for Pb-free soldering assembly

    SciTech Connect

    Tanaka, Hitoshi; Tanimoto, Morimasa; Matsuda, Akira; Uno, Takeo; Kurihara, Masaaki; Shiga, Shoji

    1999-11-01

    Pb-free solderable surface finishing is essential to implement Pb-free solder assembly in order to meet with the growing demand of environmental consciousness to eliminate Pb from electronic products. Two types of widely applicable Pb-free surface finishing technologies are developed. One is the multilayer-system including Pd with Ni undercoat. Heat-resistance of Pd enables whole-surface-plating on to leadframe before IC-assembling process. The other is the double-layer-system with low-melting-point-materials, for example, thicker Sn underlayer and thinner Sn-Bi alloy overlayer, dilutes Sn-Bi alloy's defects of harmful reactivity along with substrate metal and mechanical brittleness with keeping its advantages of solder-wettability and no whisker.

  3. Liquid on Paper: Rapid Prototyping of Soft Functional Components for Paper Electronics

    PubMed Central

    Long Han, Yu; Liu, Hao; Ouyang, Cheng; Jian Lu, Tian; Xu, Feng

    2015-01-01

    This paper describes a novel approach to fabricate paper-based electric circuits consisting of a paper matrix embedded with three-dimensional (3D) microchannels and liquid metal. Leveraging the high electric conductivity and good flowability of liquid metal, and metallophobic property of paper, it is possible to keep electric and mechanical functionality of the electric circuit even after a thousand cycles of deformation. Embedding liquid metal into paper matrix is a promising method to rapidly fabricate low-cost, disposable, and soft electric circuits for electronics. As a demonstration, we designed a programmable displacement transducer and applied it as variable resistors and pressure sensors. The unique metallophobic property, combined with softness, low cost and light weight, makes paper an attractive alternative to other materials in which liquid metal are currently embedded. PMID:26129723

  4. Specialty Task Force: A Strategic Component to Electronic Health Record (EHR) Optimization.

    PubMed

    Romero, Mary Rachel; Staub, Allison

    2016-01-01

    Post-implementation stage comes after an electronic health record (EHR) deployment. Analyst and end users deal with the reality that some of the concepts and designs initially planned and created may not be complementary to the workflow; creating anxiety, dissatisfaction, and failure with early adoption of system. Problems encountered during deployment are numerous and can vary from simple to complex. Redundant ticket submission creates backlog for Information Technology personnel resulting in delays in resolving concerns with EHR system. The process of optimization allows for evaluation of system and reassessment of users' needs. A solid and well executed optimization infrastructure can help minimize unexpected end-user disruptions and help tailor the system to meet regulatory agency goals and practice standards. A well device plan to resolve problems during post implementation is necessary for cost containment and to streamline communication efforts. Creating a specialty specific collaborative task force is efficacious and expedites resolution of users' concerns through a more structured process. PMID:27332478

  5. Control of Vertebrate Skeletal Mineralization by Polyphosphates

    PubMed Central

    Omelon, Sidney; Georgiou, John; Henneman, Zachary J.; Wise, Lisa M.; Sukhu, Balram; Hunt, Tanya; Wynnyckyj, Chrystia; Holmyard, Douglas; Bielecki, Ryszard; Grynpas, Marc D.

    2009-01-01

    Background Skeletons are formed in a wide variety of shapes, sizes, and compositions of organic and mineral components. Many invertebrate skeletons are constructed from carbonate or silicate minerals, whereas vertebrate skeletons are instead composed of a calcium phosphate mineral known as apatite. No one yet knows why the dynamic vertebrate skeleton, which is continually rebuilt, repaired, and resorbed during growth and normal remodeling, is composed of apatite. Nor is the control of bone and calcifying cartilage mineralization well understood, though it is thought to be associated with phosphate-cleaving proteins. Researchers have assumed that skeletal mineralization is also associated with non-crystalline, calcium- and phosphate-containing electron-dense granules that have been detected in vertebrate skeletal tissue prepared under non-aqueous conditions. Again, however, the role of these granules remains poorly understood. Here, we review bone and growth plate mineralization before showing that polymers of phosphate ions (polyphosphates: (PO3−)n) are co-located with mineralizing cartilage and resorbing bone. We propose that the electron-dense granules contain polyphosphates, and explain how these polyphosphates may play an important role in apatite biomineralization. Principal Findings/Methodology The enzymatic formation (condensation) and destruction (hydrolytic degradation) of polyphosphates offers a simple mechanism for enzymatic control of phosphate accumulation and the relative saturation of apatite. Under circumstances in which apatite mineral formation is undesirable, such as within cartilage tissue or during bone resorption, the production of polyphosphates reduces the free orthophosphate (PO43−) concentration while permitting the accumulation of a high total PO43− concentration. Sequestering calcium into amorphous calcium polyphosphate complexes can reduce the concentration of free calcium. The resulting reduction of both free PO43− and free

  6. A quantitative estimation of the exhaust, abrasion and resuspension components of particulate traffic emissions using electron microscopy

    NASA Astrophysics Data System (ADS)

    Weinbruch, Stephan; Worringen, Annette; Ebert, Martin; Scheuvens, Dirk; Kandler, Konrad; Pfeffer, Ulrich; Bruckmann, Peter

    2014-12-01

    The contribution of the three traffic-related components exhaust, abrasion, and resuspension to kerbside and urban background PM10 and PM1 levels was quantified based on the analysis of individual particles by scanning electron microscopy. A total of 160 samples was collected on 38 days between February and September 2009 at a kerbside and an urban background station in the urban/industrial Ruhr area (Germany). Based on size, morphology, chemical composition and stability under electron bombardment, the 111,003 particles studied in detail were classified into the following 14 particle classes: traffic/exhaust, traffic/abrasion, traffic/resuspension, carbonaceous/organic, industry/metallurgy, industry/power plants, secondary particles, (aged) sea salt, silicates, Ca sulfates, carbonates, Fe oxides/hydroxides, biological particles, and other particles. The traffic/exhaust component consists predominantly of externally mixed soot particles and soot internally mixed with secondary particles. The traffic/abrasion component contains all particles with characteristic tracer elements (Fe, Cu, Ba, Sb, Zn) for brake and tire abrasion. The traffic/resuspension component is defined by the mixing state and comprises all internally mixed particles with a high proportion of silicates or Fe oxides/hydroxides which contain soot or abrasion particles as minor constituent. In addition, silicates and Fe oxides/hydroxides internally mixed with chlorine and sulphur containing particles were also assigned to the traffic/resuspension component. The total contribution of traffic to PM10 was found to be 27% at the urban background station and 48% at the kerbside station, the corresponding values for PM1 are 15% and 39%. These values lie within the range reported in previous literature. The relative share of the different traffic components for PM10 at the kerbside station was 27% exhaust, 15% abrasion, and 58% resuspension (38%, 8%, 54% for PM1). For the urban background, the following

  7. Application of Scanning Electron Microscopy/Energy-Dispersive X-Ray Spectroscopy for Characterization of Detrital Minerals in Karst Cave Speleothems.

    PubMed

    Zupančič, Nina; Miler, Miloš; Šebela, Stanka; Jarc, Simona

    2016-02-01

    Micro-scale observations in karst caves help to identify different processes that shaped local morphology. Scanning electron microscopy/energy-dispersive X-ray spectroscopy inspection of speleothems from two karst caves in Slovenia, Predjama and Črna Jama, confirmed the presence of sub-angular to sub-rounded detrital fragments of clay minerals, feldspars, quartz, Fe-oxides/hydroxides, rutile and Nb-rutile, xenotime, kassite, allanite, fluorapatite, epidote, ilmenite, monazite, sphene, and zircon, between 2 and 50 μm across. These occur in porous layers separating calcite laminae in the clayey coating on the layer below the surface of the speleothems, and are also incorporated within actual crystals. It is likely that they are derived from the weathered rocks of the Eocene flysch. Probably they were first transported into the caves by floodwaters forming cave sediments. Later, depending upon the climate conditions, they were moved by air currents or by water to the surface of active speleothems. They might also be redeposited from overlying soils enriched with wind-transported minerals from the flysch, or from higher passages filled with weathered flysch sediment, by drip water percolating through the fissured limestone. As some of the identified minerals are carriers of rare earth elements, Ti and Zr, their presence could affect any palaeoclimatic interpretations that are based upon the geochemical composition of the speleothems. PMID:26914996

  8. Application of Scanning Electron Microscopy/Energy-Dispersive X-Ray Spectroscopy for Characterization of Detrital Minerals in Karst Cave Speleothems.

    PubMed

    Zupančič, Nina; Miler, Miloš; Šebela, Stanka; Jarc, Simona

    2016-02-01

    Micro-scale observations in karst caves help to identify different processes that shaped local morphology. Scanning electron microscopy/energy-dispersive X-ray spectroscopy inspection of speleothems from two karst caves in Slovenia, Predjama and Črna Jama, confirmed the presence of sub-angular to sub-rounded detrital fragments of clay minerals, feldspars, quartz, Fe-oxides/hydroxides, rutile and Nb-rutile, xenotime, kassite, allanite, fluorapatite, epidote, ilmenite, monazite, sphene, and zircon, between 2 and 50 μm across. These occur in porous layers separating calcite laminae in the clayey coating on the layer below the surface of the speleothems, and are also incorporated within actual crystals. It is likely that they are derived from the weathered rocks of the Eocene flysch. Probably they were first transported into the caves by floodwaters forming cave sediments. Later, depending upon the climate conditions, they were moved by air currents or by water to the surface of active speleothems. They might also be redeposited from overlying soils enriched with wind-transported minerals from the flysch, or from higher passages filled with weathered flysch sediment, by drip water percolating through the fissured limestone. As some of the identified minerals are carriers of rare earth elements, Ti and Zr, their presence could affect any palaeoclimatic interpretations that are based upon the geochemical composition of the speleothems.

  9. Immuno-electron labelling of matrix components in congenital hereditary endothelial dystrophy.

    PubMed

    Sekundo, W; Marshall, G E; Lee, W R; Kirkness, C M

    1994-06-01

    Two corneal buttons were obtained from a patient with congenital hereditary endothelial dystrophy (CHED) at the ages of 2.5 years (right eye) and 14 years (left eye) and were studied by light and electron microscopy including immunogold labelling for collagen types I-V and laminin. The posterior collagenous layer (PCL) of Descemet's membrane contained collagen types I, III-V, and laminin: the latter was also localised to fine-banded and granular material in the posterior non-banded zone (PNBZ). Comparison of the endothelium 2.5 years and 14 years revealed occasional dystrophic changes in the former and extensive dystrophic changes in the latter. The distribution of collagen types I, III and V within the PCL supports previous morphological observations of fibroblast-like change of the endothelium in CHED. Persisting endothelial properties were manifest as positive labelling of type IV collagen and laminin. An excessive amount of laminin found in PNBZ and PCL is another stress-related endothelial reaction.

  10. Model-independent electron spin resonance for measuring order of immobile components in a biological assembly.

    PubMed Central

    Burghardt, T P; Thompson, N L

    1985-01-01

    A model-independent description of the angular orientation distribution of elements in an ordered biological assembly is applied to the electron spin resonance (ESR) technique. As in a previous model-independent treatment of fluorescence polarization (Burghardt, T.P., 1984, Biopolymers, 23:2383-2406) the elemental order is described by an angular distribution of molecular frames with one frame fixed in each element of the assembly. The distribution is expanded in a complete orthonormal set of functions. The coefficients of the series expansion (the order parameters) describe the orientation distribution of the elements in the assembly without reference to a model and can be obtained from the observed spectrum. The method establishes the limitations of ESR in detecting order in the assembly by determining which distribution coefficients the technique can detect. A method of determining the order parameters from an ESR spectra, using a set of ESR basis spectra, is developed. We also describe a treatment that incorporates the actual line shape measured from randomly oriented, immobile elements. In this treatment, no model-dependent assumptions about the line shape are required. We have applied the model-independent analysis to ESR spectra from spin-labeled myosin cross-bridges in muscle fibers. The results contain detailed information on the spin-probe angular distribution and differ in interesting ways from previous model-dependent interpretations of the spectra. PMID:2994768

  11. Separation of electron-transfer and coupled chemical reaction components of biocatalytic processes using Fourier transform ac voltammetry.

    PubMed

    Fleming, Barry D; Zhang, Jie; Bond, Alan M; Bell, Stephen G; Wong, Luet-Lok

    2005-06-01

    The underlying electron-transfer and coupled chemical processes associated with biologically important catalytic reactions can be resolved using a combination of Fourier transform ac voltammetry with an analysis of the separated dc and ac components. This outcome can be achieved because the response associated with generation of the catalytic current is essentially confined to the steady-state dc component, whereas the electron-transfer step is dominant in the fundamental and higher harmonics. For the mediated oxidation of glucose with glucose oxidase, it was found that the underlying reversible redox chemistry of the mediator, ferrocenemonocarboxylic acid, as detected in the third and higher harmonics, was totally unaffected by introduction of the catalytic process. In contrast, for the catalytic reduction of molecular oxygen by cytochrome P450, slight changes in the P450 redox process were detected when the catalytic reaction was present. Simulations of a simple catalytic reaction scheme support the fidelity of this novel FT ac voltammetric approach for examining mechanistic nuances of catalytic forms of electrochemical reaction schemes.

  12. Electron transport in plasmas with lithium-coated plasma-facing components

    NASA Astrophysics Data System (ADS)

    Jacobson, Craig Michael

    The Lithium Tokamak Experiment (LTX) is a spherical tokamak designed to study the lowrecycling regime through the use of lithium-coated shells conformal to the last closed flux surface (LCFS). A lowered recycling rate is expected to flatten core Te profiles, raise edge Te, strongly affect n e profiles, and enhance confinement. To study these unique plasmas, a Thomson scattering diagnostic uses a ≤ 20 J, 30 ns FWHM pulsed ruby laser to measure Te and ne at 11 radial points on the horizontal midplane, spaced from the magnetic axis to the outer edge at a single temporal point for each discharge. Scattered light is imaged through a spectrometer onto an intensified CCD. The diagnostic is absolutely calibrated using a precision light source and Raman scattering. Measurements of n e are compared with line integrated density measurements from a microwave interferometer. Adequate signal to noise is obtained with ne ≥ 2 x10 18 m--3. Thomson profiles of plasmas following evaporation of lithium onto room-temperature plasmafacing components (PFCs) are used in conjunction with magnetic equilibria as input for TRANSP modeling runs. Neoclassical calculations are used to determine Ti profiles, which have levels that agree with passive charge exchange recombination spectroscopy (CHERS) measurements. TRANSP results for confinement times and stored energies agree with diamagnetic loop measurements. Results of chie result in values as low as 7 m2/s near the core, which rise to around 100 m2/s near the edge. These are the first measurements of chie in LTX, or its predecessor, the Current Drive Experiment-Upgrade (CDX-U), with lithium PFCs.

  13. Charge recombination processes in minerals studied using optically stimulated luminescence and time-resolved exo-electrons

    NASA Astrophysics Data System (ADS)

    Tsukamoto, Sumiko; Murray, Andrew; Ankjærgaard, Christina; Jain, Mayank; Lapp, Torben

    2010-08-01

    A time-resolved optically stimulated exo-electron (TR-OSE) measurement system has been developed using a Photon Timer attached to a gas-flow semi-proportional pancake electron detector within a Risø TL/OSL reader. The decay rate of the exo-electron emission after the stimulation pulse depends on the probability of (1) escape of electrons into the detector gas from the conduction band by overcoming the work function of the material and (2) thermalization of electrons in the conduction band, and subsequent re-trapping/recombination. Thus, we expect the exo-electron signal to reflect the instantaneous electron concentration in the conduction band. In this study, TR-OSE and time-resolved optically stimulated luminescence (TR-OSL) were measured for the first time using quartz, K-feldspar and NaCl by stimulating the samples using pulsed blue LEDs at different temperatures between 50 and 250 °C after beta irradiation and preheating to 280 °C. The majority of TR-OSE signals from all the samples decayed much faster than TR-OSL signals irrespective of the stimulation temperatures. This suggests that the lifetime of OSL in these dosimeters arises mainly from the relaxation of an excited state of the recombination centre, rather than from residence time of an electron in the conduction band.

  14. Extraction of mineral elements from inedible wastes of biological components of a life-support system and their utilization for plant nutrition

    NASA Astrophysics Data System (ADS)

    Gribovskaya, I. V.; Gladchenko, I. A.; Zinenko, G. K.

    Two methods of extracting mineral elements from otherwise deadlock products of a life-support system are presented. We describe first optimum conditions for recovering elements by water extraction from dry wastes of plants, biomass ash, and solid human wastes after passing them through the catalytic furnace; and, second, we describe acid extracts of biogenous elements by 1N and 2N HNO_3 from these products. Ways to use the extracts of elements in plant nutrition are considered in order to increase the extent to which the mineral loop of a life-support system can be closed.

  15. Interpreting Al-in Hornblende and Hbl-Plag thermobarometry results from the Tuolumne batholith and magmatic lobes in conjunction with single mineral element distribution electron microprobe maps

    NASA Astrophysics Data System (ADS)

    Memeti, V.; Krause, J.; Anderson, J. L.; Paterson, S. R.

    2009-12-01

    Several recent thermobarometry studies have been conducted on the 95-85 Ma Tuolumne batholith, Sierra Nevada, CA, since Ague & Brimhall (1988) first reported ~2.5-3 kbar pressures and an emplacement depth of ~ 10 km from these sphene bearing granodioritic rocks. Average pressure estimates from more recent reports using the simultaneous solution of the plagioclase-amphibole thermometer by Holland & Blundy (1994), and the temperature corrected Al-in-hornblende barometer by Anderson & Smith (1995) are around 2 kbar, but vary in detail from 2 to 3 kbar. Further complications are revealed on temperature-pressure plots since some results fall below the granite and tonalite solidi and are thus subsolidus in nature. Many recent studies also indicate that single minerals in volcanic and plutonic rocks preserve complex magmatic growth histories, and in one sample or thin section can show heterogeneous mineral chemistries and multiple mineral populations, likely due to recycling and mixing processes occurring in large magma chambers. This implies that the pairing of minerals for thermobarometry calculations and thus the usage of these methods is complicated and requires the prior evaluation of the geochemistry of the individual minerals used for the analyses. We have done pressure and temperature estimates using the thermometer by Holland & Blundy (1994) and the Al-in-hornblende barometer by Anderson & Smith (1995) in conjunction with X-ray electron microprobe element distribution maps of the amphiboles and plagioclase grains used for the thermobarometry. With this approach, we attempt to better control the process of analyses pairing for the calculations since we establish a better awareness of the nature of individual mineral chemistry heterogeneities and the presence of multiple mineral populations. We selected a number of granodiorite samples from the peripheral magmatic lobes of the batholith, which have been determined to represent less complex and shorter lived, local

  16. Design and fabrication of circular and rectangular components for electron-cyclotron-resonant heating of tandem mirror experiment-upgrade

    SciTech Connect

    Felker, B.; Calderon, M.O.; Chargin, A.K.; Coffield, F.E.; Lang, D.D.; Rubert, R.R.; Pedrotti, L.R.; Stallard, B.W.; Gallagher, N.C. Jr.; Sweeney, D.W.

    1983-11-18

    The electron-cyclotron-resonant heating (ECRH) systems of rectangular waveguides on Tandem Mirror Experiment-Upgrade (TMX-U) operated with a overall efficiency of 50%, each system using a 28-GHz, 200-kW pulsed gyrotron. We designed and built four circular-waveguide systems with greater efficiency and greater power-handling capabilities to replace the rectangular waveguides. Two of these circular systems, at the 5-kG second-harmonic heating locations, have a total transmission efficiency of >90%. The two systems at the 10-kG fundamental heating locations have a total transmission efficiency of 80%. The difference in efficiency is due to the additional components required to launch the microwaves in the desired orientation and polarization with respect to magnetic-field lines at the 10-kG points. These systems handle the total power available from each gyrotron but do not have the arcing limitation problem of the rectangular waveguide. Each system requires several complex components. The overall physical layout and the design considerations for the rectangular and circular waveguide components are described here.

  17. Conceptual Design of Vacuum Chamber for testing of high heat flux components using electron beam as a source

    NASA Astrophysics Data System (ADS)

    Khan, M. S.; Swamy, Rajamannar; Khirwadkar, S. S.; Divertors Division, Prototype

    2012-11-01

    A conceptual design of vacuum chamber is proposed to study the thermal response of high heat flux components under energy depositions of the magnitude and durations expected in plasma fusion devices. It is equipped with high power electron beam with maximum beam power of 200 KW mounted in a stationary horizontal position from back side of the chamber. The electron beam is used as a heat source to evaluate the heat removal capacity, material performance under thermal loads & stresses, thermal fatigue etc on actively cooled mock - ups which are mounted on a flange system which is the front side door of the chamber. The tests mock - ups are connected to a high pressure high temperature water circulation system (HPHT-WCS) operated over a wide range of conditions. The vacuum chamber consists of different ports at different angles to view the mock -up surface available for mock -up diagnostics. The vacuum chamber is pumped with different pumps mounted on side ports of the chamber. The chamber is shielded from X - rays which are generated inside the chamber when high-energy electrons are incident on the mock-up. The design includes development of a conceptual design with theoretical calculations and CAD modelling of the system using CATIA V5. These CAD models give an outline on the complete geometry of HHF test chamber, fabrication challenges and safety issues. FEA analysis of the system has been performed to check the structural integrity when the system is subjected to structural & thermal loads.

  18. Mass transfer in fuel cells. [electron microscopy of components, thermal decomposition of Teflon, water transport, and surface tension of KOH solutions

    NASA Technical Reports Server (NTRS)

    Walker, R. D., Jr.

    1973-01-01

    Results of experiments on electron microscopy of fuel cell components, thermal decomposition of Teflon by thermogravimetry, surface area and pore size distribution measurements, water transport in fuel cells, and surface tension of KOH solutions are described.

  19. Electronic and optical characteristics of an m-plane GaN single crystal grown by hydride vapor phase epitaxy on a GaN seed synthesized by the ammonothermal method using an acidic mineralizer

    NASA Astrophysics Data System (ADS)

    Kojima, Kazunobu; Tsukada, Yusuke; Furukawa, Erika; Saito, Makoto; Mikawa, Yutaka; Kubo, Shuichi; Ikeda, Hirotaka; Fujito, Kenji; Uedono, Akira; Chichibu, Shigefusa F.

    2016-05-01

    Fundamental electronic and optical properties of a low-resistivity m-plane GaN single crystal, which was grown by hydride vapor phase epitaxy on a bulk GaN seed crystal synthesized by the ammonothermal method in supercritical ammonia using an acidic mineralizer, were investigated. The threading dislocation and basal-plane staking-fault densities of the crystal were around 104 cm-2 and less than 100 cm-1, respectively. Oxygen doping achieved a high electron concentration of 4 × 1018 cm-3 at room temperature. Accordingly, a photoluminescence (PL) band originating from the recombination of hot carriers was observed at low temperatures, even under weak excitation conditions. The simultaneous realization of low-level incorporation of Ga vacancies (VGa) less than 1016 cm-3 was confirmed by using the positron annihilation technique. Consistent with our long-standing claim that VGa complexes are the major nonradiative recombination centers in GaN, the fast-component PL lifetime of the near-band-edge emission at room temperature longer than 2 ns was achieved.

  20. ePhenotyping for Abdominal Aortic Aneurysm in the Electronic Medical Records and Genomics (eMERGE) Network: Algorithm Development and Konstanz Information Miner Workflow

    PubMed Central

    Borthwick, Kenneth M; Smelser, Diane T; Bock, Jonathan A; Elmore, James R; Ryer, Evan J; Ye, Zi; Pacheco, Jennifer A.; Carrell, David S.; Michalkiewicz, Michael; Thompson, William K; Pathak, Jyotishman; Bielinski, Suzette J; Denny, Joshua C; Linneman, James G; Peissig, Peggy L; Kho, Abel N; Gottesman, Omri; Parmar, Harpreet; Kullo, Iftikhar J; McCarty, Catherine A; Böttinger, Erwin P; Larson, Eric B; Jarvik, Gail P; Harley, John B; Bajwa, Tanvir; Franklin, David P; Carey, David J; Kuivaniemi, Helena; Tromp, Gerard

    2015-01-01

    Background and objective We designed an algorithm to identify abdominal aortic aneurysm cases and controls from electronic health records to be shared and executed within the “electronic Medical Records and Genomics” (eMERGE) Network. Materials and methods Structured Query Language, was used to script the algorithm utilizing “Current Procedural Terminology” and “International Classification of Diseases” codes, with demographic and encounter data to classify individuals as case, control, or excluded. The algorithm was validated using blinded manual chart review at three eMERGE Network sites and one non-eMERGE Network site. Validation comprised evaluation of an equal number of predicted cases and controls selected at random from the algorithm predictions. After validation at the three eMERGE Network sites, the remaining eMERGE Network sites performed verification only. Finally, the algorithm was implemented as a workflow in the Konstanz Information Miner, which represented the logic graphically while retaining intermediate data for inspection at each node. The algorithm was configured to be independent of specific access to data and was exportable (without data) to other sites. Results The algorithm demonstrated positive predictive values (PPV) of 92.8% (CI: 86.8-96.7) and 100% (CI: 97.0-100) for cases and controls, respectively. It performed well also outside the eMERGE Network. Implementation of the transportable executable algorithm as a Konstanz Information Miner workflow required much less effort than implementation from pseudo code, and ensured that the logic was as intended. Discussion and conclusion This ePhenotyping algorithm identifies abdominal aortic aneurysm cases and controls from the electronic health record with high case and control PPV necessary for research purposes, can be disseminated easily, and applied to high-throughput genetic and other studies. PMID:27054044

  1. All-electron formalism for total energy strain derivatives and stress tensor components for numeric atom-centered orbitals

    NASA Astrophysics Data System (ADS)

    Knuth, Franz; Carbogno, Christian; Atalla, Viktor; Blum, Volker; Scheffler, Matthias

    2015-05-01

    We derive and implement the strain derivatives of the total energy of solids, i.e., the analytic stress tensor components, in an all-electron, numeric atom-centered orbital based density-functional formalism. We account for contributions that arise in the semi-local approximation (LDA/GGA) as well as in the generalized Kohn-Sham case, in which a fraction of exact exchange (hybrid functionals) is included. In this work, we discuss the details of the implementation including the numerical corrections for sparse integrations grids which allow to produce accurate results. We validate the implementation for a variety of test cases by comparing to strain derivatives performed via finite differences. Additionally, we include the detailed definition of the overlapping atom-centered integration formalism used in this work to obtain total energies and their derivatives.

  2. Non-rigid registration and non-local principle component analysis to improve electron microscopy spectrum images

    NASA Astrophysics Data System (ADS)

    Yankovich, Andrew B.; Zhang, Chenyu; Oh, Albert; Slater, Thomas J. A.; Azough, Feridoon; Freer, Robert; Haigh, Sarah J.; Willett, Rebecca; Voyles, Paul M.

    2016-09-01

    Image registration and non-local Poisson principal component analysis (PCA) denoising improve the quality of characteristic x-ray (EDS) spectrum imaging of Ca-stabilized Nd2/3TiO3 acquired at atomic resolution in a scanning transmission electron microscope. Image registration based on the simultaneously acquired high angle annular dark field image significantly outperforms acquisition with a long pixel dwell time or drift correction using a reference image. Non-local Poisson PCA denoising reduces noise more strongly than conventional weighted PCA while preserving atomic structure more faithfully. The reliability of and optimal internal parameters for non-local Poisson PCA denoising of EDS spectrum images is assessed using tests on phantom data.

  3. Impact of the amount of working fluid in loop heat pipe to remove waste heat from electronic component

    NASA Astrophysics Data System (ADS)

    Smitka, Martin; Kolková, Z.; Nemec, Patrik; Malcho, M.

    2014-03-01

    One of the options on how to remove waste heat from electronic components is using loop heat pipe. The loop heat pipe (LHP) is a two-phase device with high effective thermal conductivity that utilizes change phase to transport heat. It was invented in Russia in the early 1980's. The main parts of LHP are an evaporator, a condenser, a compensation chamber and a vapor and liquid lines. Only the evaporator and part of the compensation chamber are equipped with a wick structure. Inside loop heat pipe is working fluid. As a working fluid can be used distilled water, acetone, ammonia, methanol etc. Amount of filling is important for the operation and performance of LHP. This work deals with the design of loop heat pipe and impact of filling ratio of working fluid to remove waste heat from insulated gate bipolar transistor (IGBT).

  4. Dynamic Mechanical Properties and Thermal Effect of an Epoxy Resin Composite, Encapsulation's Element of a New Electronic Component

    NASA Astrophysics Data System (ADS)

    Rmili, W.; Deffarges, M. P.; Chalon, F.; Ma, Z.; Leroy, R.

    2013-11-01

    Epoxy resin is used in many industrial applications principally in the microelectronic field to protect integrated circuits. However, these components are subject to various environments such as moisture and thermal fluctuations during packaging. Consequently, mechanical, physical and chemical properties of the resin can be affected. For an epoxy resin composite designed for a future application, an evaluation of the relevant properties was carried out using a dynamic mechanical analyzer and a thermogravimetric analysis (TGA) instrument. The surface morphology was investigated using scanning electron microscopy to examine the impact of post-cured treatment through evolution of the rigidity and of the glass transition temperature. Subsequently, a temperature classification was proposed to define the temperature limit for safe use of the material. Finally, temperature degradation was observed and confirmed by TGA tests. Results from all of these analyses bring understanding to the phenomenon of thermal degradation and its influence on the stability of the epoxy resin composite.

  5. Effects of the Electronic Spin Transitions of Iron in Lower Mantle Minerals: Implications for Deep Mantle Geophysics and Geochemistry

    NASA Astrophysics Data System (ADS)

    Lin, Jung-Fu; Speziale, Sergio; Mao, Zhu; Marquardt, Hauke

    2013-04-01

    We have critically reviewed and discussed currently available information regarding the spin and valence states of iron in lower mantle minerals and the associated effects of the spin transitions on physical, chemical, and transport properties of the deep Earth. A high-spin to low-spin crossover of Fe2+ in ferropericlase has been observed to occur at pressure-temperature conditions corresponding to the middle part of the lower mantle. In contrast, recent studies consistently show that Fe2+ predominantly exhibits extremely high quadrupole splitting values in the pseudo-dodecahedral site (A site) of perovskite and post-perovskite, indicative of a strong lattice distortion. Fe3+ in the A site of these structures likely remains in the high-spin state, while a high-spin to low-spin transition of Fe3+ in the octahedral site of perovskite occurs at pressures of 15-50 GPa. In post-perovskite, the octahedral-site Fe3+ remains in the low-spin state at the pressure conditions of the lowermost mantle. These changes in the spin and valence states of iron as a function of pressure and temperature have been reported to affect physical, chemical, rheological, and transport properties of the lower mantle minerals. The spin crossover of Fe2+ in ferropericlase has been documented to affect these properties and is discussed in depth here, whereas the effects of the spin transition of iron in perovskite and post-perovskite are much more complex and remain debated. The consequences of the transitions are evaluated in terms of their implications to deep Earth geophysics, geochemistry, and geodynamics including elasticity, element partitioning, fractionation and diffusion, and rheological and transport properties.

  6. Investigation of the mineral components of porcelain raw material and their phase evolution during a firing process by using a Rietveld quantitative analysis

    NASA Astrophysics Data System (ADS)

    Kim, Jaegyeom; Heo, Eunae; Kim, Seung-Joo; Kim, Jong-Young

    2016-01-01

    A ceramic raw material for white porcelain and its phase evolution during a firing process were investigated by using Rietveld method based on powder X-ray diffraction data. The raw material was mainly composed of five mineral phases: quartz (SiO2), microcline (KAlSi3O8), albite (NaAlSi3O8), muscovite (KAl2(AlSi3O10)(OH)2), and kaolinite (Al2Si2O5(OH)4). The amount of each mineral phase could be determined by using Rietveld quantitative phase analyses. During the firing process, the microcline, albite, muscovite and kaolinite phases started to react with each other to produce the mullite phase embedded in an amorphous matrix. The amount of quartz remained nearly unchanged until a temperature above 1200 °C; then, it converted to an amorphous phase at higher temperatures.

  7. Amino acid and mineral composition of protein and other components and their recovery yields from whole Antarctic krill (Euphausia superba) using isoelectric solubilization/precipitation.

    PubMed

    Chen, Y-C; Tou, J C; Jaczynski, J

    2009-03-01

    Proteins and insolubles were recovered from whole Antarctic krill via novel isoelectric solubilization/precipitation using different pH treatments. The protein recovery yield was 45% to 50% (dry basis). The recovered proteins had higher (P < 0.05) content of essential amino acids (EAAs) and non-EAAs as well as higher (P < 0.05) ratio of total EAA/total AA than whole krill. The EAAs constituted almost 50% of total AAs. The least extreme pH treatments (pHs 3 and 12) yielded highest (P < 0.05) content of EAAs. The quality of recovered proteins was high based on EAAs meeting FAO/WHO/UNU recommendations for adults and infants. The basic pH yielded proteins with the lowest (P < 0.05) amount of minerals and the highest (P < 0.05) amount of Ca, P, and Mg in the insolubles when compared to the acidic treatments. However, both basic and acidic treatments effectively removed minerals from recovered proteins without the removal of the exoskeleton before processing. Therefore, besides high-quality proteins, the insolubles may provide a mineral supplement in the animal diet.

  8. Investigation of the mechanical performance of Siemens linacs components during arc: gantry, MLC, and electronic portal imaging device

    PubMed Central

    Rowshanfarzad, Pejman; Häring, Peter; Riis, Hans L; Zimmermann, Sune J; Ebert, Martin A

    2015-01-01

    Background In radiotherapy treatments, it is crucial to monitor the performance of linac components including gantry, collimation system, and electronic portal imaging device (EPID) during arc deliveries. In this study, a simple EPID-based measurement method is suggested in conjunction with an algorithm to investigate the stability of these systems at various gantry angles with the aim of evaluating machine-related errors in treatments. Methods The EPID sag, gantry sag, changes in source-to-detector distance (SDD), EPID and collimator skewness, EPID tilt, and the sag in leaf bank assembly due to linac rotation were separately investigated by acquisition of 37 EPID images of a simple phantom with five ball bearings at various gantry angles. A fast and robust software package was developed for automated analysis of image data. Three Siemens linacs were investigated. Results The average EPID sag was within 1 mm for all tested linacs. Two machines showed >1 mm gantry sag. Changes in the SDD values were within 7.5 mm. EPID skewness and tilt values were <1° in all machines. The maximum sag in leaf bank assembly was <1 mm. Conclusion The method and software developed in this study provide a simple tool for effective investigation of the behavior of Siemens linac components with gantry rotation. Such a comprehensive study has been performed for the first time on Siemens machines. PMID:26604840

  9. Efficient Parallel All-Electron Four-Component Dirac-Kohn-Sham Program Using a Distributed Matrix Approach II.

    PubMed

    Storchi, Loriano; Rampino, Sergio; Belpassi, Leonardo; Tarantelli, Francesco; Quiney, Harry M

    2013-12-10

    We propose a new complete memory-distributed algorithm, which significantly improves the parallel implementation of the all-electron four-component Dirac-Kohn-Sham (DKS) module of BERTHA (J. Chem. Theory Comput. 2010, 6, 384). We devised an original procedure for mapping the DKS matrix between an efficient integral-driven distribution, guided by the structure of specific G-spinor basis sets and by density fitting algorithms, and the two-dimensional block-cyclic distribution scheme required by the ScaLAPACK library employed for the linear algebra operations. This implementation, because of the efficiency in the memory distribution, represents a leap forward in the applicability of the DKS procedure to arbitrarily large molecular systems and its porting on last-generation massively parallel systems. The performance of the code is illustrated by some test calculations on several gold clusters of increasing size. The DKS self-consistent procedure has been explicitly converged for two representative clusters, namely Au20 and Au34, for which the density of electronic states is reported and discussed. The largest gold cluster uses more than 39k basis functions and DKS matrices of the order of 23 GB. PMID:26592273

  10. X-ray spectroscopy of warm and hot electron components in the CAPRICE source plasma at EIS testbench at GSI

    NASA Astrophysics Data System (ADS)

    Mascali, D.; Celona, L.; Maimone, F.; Maeder, J.; Castro, G.; Romano, F. P.; Musumarra, A.; Altana, C.; Caliri, C.; Torrisi, G.; Neri, L.; Gammino, S.; Tinschert, K.; Spaedtke, K. P.; Rossbach, J.; Lang, R.; Ciavola, G.

    2014-02-01

    An experimental campaign aiming to detect X radiation emitted by the plasma of the CAPRICE source - operating at GSI, Darmstadt - has been carried out. Two different detectors (a SDD - Silicon Drift Detector and a HpGe - hyper-pure Germanium detector) have been used to characterize the warm (2-30 keV) and hot (30-500 keV) electrons in the plasma, collecting the emission intensity and the energy spectra for different pumping wave frequencies and then correlating them with the CSD of the extracted beam measured by means of a bending magnet. A plasma emissivity model has been used to extract the plasma density along the cone of sight of the SDD and HpGe detectors, which have been placed beyond specific collimators developed on purpose. Results show that the tuning of the pumping frequency considerably modifies the plasma density especially in the warm electron population domain, which is the component responsible for ionization processes: a strong variation of the plasma density near axis region has been detected. Potential correlations with the charge state distribution in the plasma are explored.

  11. X-ray spectroscopy of warm and hot electron components in the CAPRICE source plasma at EIS testbench at GSI

    SciTech Connect

    Mascali, D. Celona, L.; Castro, G.; Torrisi, G.; Neri, L.; Gammino, S.; Ciavola, G.; Maimone, F.; Maeder, J.; Tinschert, K.; Spaedtke, K. P.; Rossbach, J.; Lang, R.; Romano, F. P.; Musumarra, A.; Altana, C.; Caliri, C.

    2014-02-15

    An experimental campaign aiming to detect X radiation emitted by the plasma of the CAPRICE source – operating at GSI, Darmstadt – has been carried out. Two different detectors (a SDD – Silicon Drift Detector and a HpGe – hyper-pure Germanium detector) have been used to characterize the warm (2–30 keV) and hot (30–500 keV) electrons in the plasma, collecting the emission intensity and the energy spectra for different pumping wave frequencies and then correlating them with the CSD of the extracted beam measured by means of a bending magnet. A plasma emissivity model has been used to extract the plasma density along the cone of sight of the SDD and HpGe detectors, which have been placed beyond specific collimators developed on purpose. Results show that the tuning of the pumping frequency considerably modifies the plasma density especially in the warm electron population domain, which is the component responsible for ionization processes: a strong variation of the plasma density near axis region has been detected. Potential correlations with the charge state distribution in the plasma are explored.

  12. Direct observation of nitrate and sulfate formations from mineral dust and sea-salts using low- Z particle electron probe X-ray microanalysis

    NASA Astrophysics Data System (ADS)

    Hwang, HeeJin; Ro, Chul-Un

    In the present work, it is demonstrated that a single particle analytical technique, named low- Z particle electron probe X-ray microanalysis, is a practically useful tool for the study of heterogeneous reactions of mineral dust and sea-salts when this analytical technique was applied to a sample collected during an Asian Dust storm event. The technique does not require a special treatment of sample to identify particles reacted in the air. Also, quantitative chemical speciation of reacted particles can provide concrete information on what chemical reaction, if any, occurred for individual particles. Among overall 178 analyzed particles, the number of reacted particles is 81 and heterogeneous chemical reactions mostly occurred on CaCO 3 mineral dust (54 particles) and sea-salts (26 particles). Several observations made for the Asian Dust sample in the present work are: (1) CaCO 3 species almost completely reacted to produce mostly Ca(NO 3) 2 species, and CaSO 4 to a much lesser extent. (2) When reacted particles contain CaSO 4, almost all of them are internally mixed with nitrate. (3) Reacted CaCO 3 particles seem to contain moisture when they were collected. (4) Some reacted CaCO 3 particles have unreacted mineral species, such as aluminosilicates, iron oxide, SiO 2, etc., in the core region. (5) All sea-salt particles are observed to have reacted in the air. Some of them were recrystallized in the air before being collected and they are observed as crystalline NaNO 3 particles. (6) Many sea-salts were collected as water drops, and some of them were fractionally recrystallized on Ag collecting substrate. When sea-salts were not recrystallized on the substrate, they are found as particles internally mixed with NaNO 3 and Mg(NO 3) 2, and in some cases SO 4 and Cl species as additional anions.

  13. Binding of Pseudomonas aeruginosa Apo-Bacterioferritin Associated Ferredoxin to Bacterioferritin B Promotes Heme Mediation of Electron Delivery and Mobilization of Core Mineral Iron†

    PubMed Central

    Weeratunga, Saroja K.; Gee, Casey E.; Lovell, Scott; Zeng, Yuhong; Woodin, Carrie L.; Rivera, Mario

    2009-01-01

    The bfrB gene from Pseudomonas aeruginosa was cloned and expressed in E. coli. The resultant protein (BfrB), which assembles into a 445.3 kDa complex0020from 24 identical subunits, binds 12 molecules of heme axially coordinated by two Met residues. BfrB, isolated with 5–10 iron atoms per protein molecule, was reconstituted with ferrous ions to prepare samples with a core mineral containing 600 ± 40 ferric ions per BfrB molecule and approximately one phosphate molecule per iron atom. In the presence of sodium dithionite or in the presence of P. aeruginosa ferredoxin NADP reductase (FPR) and NADPH the heme in BfrB remains oxidized and the core iron mineral is mobilized sluggishly. In stark contrast, addition of NADPH to a solution containing BfrB, FPR and the apo-form of P. aeruginosa bacterioferritin associated ferredoxin (apo-Bfd) results in rapid reduction of the heme in BfrB and in the efficient mobilization of the core iron mineral. Results from additional experimentation indicate that Bfd must bind to BfrB to promote heme mediation of electrons from the surface to the core to support the efficient mobilization of ferrous ions from BfrB. In this context, the thus far mysterious role of heme in bacterioferritins has been brought to the front by reconstituting BfrB with its physiological partner, apo-Bfd. These findings are discussed in the context of a model for the utilization of stored iron in which the significant upregulation of the bfd gene under low-iron conditions [Ochsner, U.A., Wilderman, P.J., Vasil, A.I., and Vasil, M.L. (2002) Mol. Microbiol. 45, 1277–1287] ensures sufficient concentrations of apo-Bfd to bind BfrB and unlock the iron stored in its core. Although these findings are in contrast to previous speculations suggesting redox mediation of electron transfer by holo-Bfd, the ability of apo-Bfd to promote iron mobilization is an economical strategy used by the cell because it obviates the need to further deplete cellular iron levels to

  14. Determination of trace element mineral/liquid partition coefficients in melilite and diopside by ion and electron microprobe techniques

    NASA Technical Reports Server (NTRS)

    Kuehner, S. M.; Laughlin, J. R.; Grossman, L.; Johnson, M. L.; Burnett, D. S.

    1989-01-01

    The applicability of ion microprobe (IMP) for quantitative analysis of minor elements (Sr, Y, Zr, La, Sm, and Yb) in the major phases present in natural Ca-, Al-rich inclusions (CAIs) was investigated by comparing IMP results with those of an electron microprobe (EMP). Results on three trace-element-doped glasses indicated that it is not possible to obtain precise quantitative analysis by using IMP if there are large differences in SiO2 content between the standards used to derive the ion yields and the unknowns.

  15. Electron

    NASA Astrophysics Data System (ADS)

    Springford, Michael

    1997-03-01

    1. J. J. Thomson and the discovery of the electron A. B. P. Pippard; 2. The isolated electron W. N. Cottingham; 3. The relativistic electron D. I. Olive; 4. The electron glue B. L. Gyorffy; 5. The electron fluid P. Coleman; 6. The magnetic electron G. G. Lonzarich; 7. The paired electron A. J. Leggett; 8. The heavy electron M. Springford; 9. The coherent electron Y. Imry and M. Peskin; 10. The composite electron R. Nicholas; 11. The electron in the cosmos M. S. Longair.

  16. Electron

    NASA Astrophysics Data System (ADS)

    Springford, Michael

    2008-12-01

    1. J. J. Thomson and the discovery of the electron A. B. P. Pippard; 2. The isolated electron W. N. Cottingham; 3. The relativistic electron D. I. Olive; 4. The electron glue B. L. Gyorffy; 5. The electron fluid P. Coleman; 6. The magnetic electron G. G. Lonzarich; 7. The paired electron A. J. Leggett; 8. The heavy electron M. Springford; 9. The coherent electron Y. Imry and M. Peskin; 10. The composite electron R. Nicholas; 11. The electron in the cosmos M. S. Longair.

  17. Mineral Chart

    MedlinePlus

    ... How Can I Help a Friend Who Cuts? Mineral Chart KidsHealth > For Teens > Mineral Chart Print A A A Text Size en ... sources of calcium. You'll also find this mineral in broccoli and dark green, leafy vegetables. Soy ...

  18. Investigations of irradiation effects on electronic components to be used in VUV-FEL and X-FEL facilities at DESY

    NASA Astrophysics Data System (ADS)

    Rybka, Dominik; Kalicki, Arkadiusz; Pozniak, Krzysztof; Romaniuk, Ryszard; Mukherjee, Bhaskar; Simrock, Stefan

    2005-09-01

    Electronic components during High Energy Physics experiments are exposed to high level of radiation. Radiation environment causes many problems to electronic devices. The goal of several experiments done at DESY (Deutsches Elektronen Synchrotron, Hamburg) was to investigate nature of irradiation effects, caused damages and possible techniques of mitigation. One of aspects of experiments is radiation measurements. The propositions of building radiation monitoring system, using different semiconductor components, are presented. Second aspect is radiation tolerance. Different electronic devices were tested: FPGA chips, CCD sensors, bubble dosimeters and LED diodes. Components were irradiated in TESLA Test Facility 2 tunnel and in laboratory using 241Am/Be neutron source. The results of experiments are included and discussed.

  19. Management status of end-of-life vehicles and development strategies of used automotive electronic control components recycling industry in China.

    PubMed

    Wang, Junjun; Chen, Ming

    2012-11-01

    Recycling companies play a leading role in the system of end-of-life vehicles (ELVs) in China. Automotive manufacturers in China are rarely involved in recycling ELVs, and they seldom provide dismantling information for recycling companies. In addition, no professional shredding plant is available. The used automotive electronic control components recycling industry in China has yet to take shape because of the lack of supporting technology and profitable models. Given the rapid growth of the vehicle population and electronic control units in automotives in China, the used automotive electronic control components recycling industry requires immediate development. This paper analyses the current recycling system of ELVs in China and introduces the automotive product recycling technology roadmap as well as the recycling industry development goals. The strengths, weaknesses, opportunities and challenges of the current used automotive electronic control components recycling industry in China are analysed comprehensively based on the 'strengths, weaknesses, opportunities and threats' (SWOT) method. The results of the analysis indicate that this recycling industry responds well to all the factors and has good opportunities for development. Based on the analysis, new development strategies for the used automotive electronic control components recycling industry in accordance with the actual conditions of China are presented.

  20. Structural, elastic, electronic and optical properties of various mineral phases of TiO2 from first-principles calculations

    NASA Astrophysics Data System (ADS)

    Liu, Qi-Jun; Zhang, Ning-Chao; Liu, Fu-Sheng; Liu, Zheng-Tang

    2014-07-01

    Titanium dioxide is well known as a semiconductor material, which attracts a great deal of attention for promising applications in many fields due to its outstanding physical and chemical properties. To investigate the structural, elastic, mechanical, electronic and optical properties of various TiO2 phases systematically, we present the ultrasoft pseudopotential planewave method within local density approximation and generalized gradient approximation, as well as the norm-conserving pseudopotential within hybrid functional B3LYP by first-principles calculations on fluorite, pyrite, rutile, anatase, hollandite, brookite, columbite, cotunnite, bronze and baddeleyite TiO2 phases. The structural parameters of ten phases are calculated, which are shown to be consistent with previous theoretical and experimental data. We obtain the elastic constants of ten phases and then estimate the bulk, shear and Young’s moduli, Poisson’s coefficient and Lamé’s constants using the Voigt-Reuss-Hill approximation. The energy band structures, density of states and charge populations of ten phases were obtained and indicated there is covalency in TiO2. Moreover, the complex dielectric function, refractive index and extinction coefficient of the ten phases were calculated; this data can aid future experimental research.

  1. Zernike phase contrast cryo-electron microscopy reveals 100 kDa component in a protein complex

    NASA Astrophysics Data System (ADS)

    Wu, Yi-Min; Wang, Chun-Hsiung; Chang, Jen-wei; Chen, Yi-yun; Miyazaki, Naoyuki; Murata, Kazuyoshi; Nagayama, Kuniaki; Chang, Wei-Hau

    2013-12-01

    Cryo-electron microscopy (cryo-EM) has become a powerful technique for obtaining near atomic structures for large protein assemblies or large virus particles, but the application to protein particles smaller than 200-300 kDa has been hampered by the feeble phase contrast obtained for such small samples and the limited number of electrons tolerated by them without incurring excessive radiation damage. By implementing a thin-film quarter-wave phase plate to a cryo-EM, Nagayama, one of the present authors, has recently restored the long-lost very low spatial frequencies, generating in-focus phase contrast superior to that of conventional defocusing phase contrast, and successfully applied the so-called Zernike phase-plate cryo-EM to target various biological samples in native state. Nevertheless, the sought-after goal of using enhanced phase contrast to reveal a native protein as small as 100 kDa waits to be realized. Here, we report a study in which 200 kV Zernike phase-plate cryo-EM with a plate cut-on periodicity of 36 nm was applied to visualize 100 kDa components of various protein complexes, including the small domains on the surface of an icosahedral particle of ˜38 nm derived from the dragon grouper nervous necrosis virus (DGNNV) and the labile sub-complex dissociated from yeast RNA polymerase III of 17 nm. In the former case, we observed a phase contrast reversal phenomenon at the centre of the icosahedral particle and traced its root cause to the near matching of the cut-on size and the particle size. In summary, our work has demonstrated that Zernike phase-plate implementation can indeed expand the size range of proteins that can be successfully investigated by cryo-EM, opening the door for countless proteins. Finally, we briefly discuss the possibility of using a transfer lens system to enlarge the cut-on periodicity without further miniaturizing the plate pinhole.

  2. [Research on the mineral phase and component of non-crystalline and nano-crystalline corrosion products on bronzes unearthed from Shang Tomb in Xingan].

    PubMed

    Cheng, Xiao-lin; Pan, Lu

    2012-05-01

    The patinas on bronzes in Shang Tomb of Xingan were powdery, pale green, which were more like "bronze disease", but the mineral composition of patinas was not paratacamite or atacamite. Micro X-ray diffraction (XRD) and high performance transmission electroscope (HTEM) showed that the patinas were mainly composed of non-crystalline and nano-crystalline SnO2, and the size of nano-crystalline particle was in the range of 4-5.7 nm; Moreover, the energy-dispersive X-ray spectrometry showed that element tin is the primary ingredient of the sample, as well as little copper, silicon, lead and iron were detected. By studying the crystal lattice stripe image of the nanometer SnO2, it was deduced that the chemical formula of nano-crystalline SnO2 did not include other elements; The Raman spectrum of the sample showed that there were not any characteristic peaks of SnO2, the spectrum was more like non-crystalline SnO2, and the weak and broad peak of 973 cm(-1) indicated that the sample may contain silicate grains, It was inferred that little of copper, silicon, lead and iron should exist in the form of non-crystalline silicate particles.

  3. Effect of gamma radiation and accelerated electron beam on stable paramagnetic centers induction in bone mineral: influence of dose, irradiation temperature and bone defatting.

    PubMed

    Jastrzebska, Anna; Kaminski, Artur; Grazka, Ewelina; Marowska, Joanna; Sadlo, Jaroslaw; Gut, Grzegorz; Uhrynowska-Tyszkiewicz, Izabela

    2014-09-01

    Ionizing radiation has been found to induce stable defects in the crystalline lattice of bone mineral hydroxyapatite, defined as CO(2) (-) radical ions possessing spins. The purpose of our study was to evaluate CO(2) (-) radical ions induced in non-defatted or defatted human compact bone by gamma radiation (G) and accelerated electron beam (EB), applied with two doses at different temperatures. Moreover, the potential effect of free radical ion formation on mechanical parameters of compact bone, tested under compression in the previous studies, was evaluated. Bone rings from femoral shafts of six male donors (age 51 ± 3 years) were collected and assigned to sixteen experimental groups according to different processing methods (non-defatted or defatted), G and EB irradiation dose (25 or 35 kGy), and irradiation temperature [ambient temperature (AT) or dry ice (DI)]. Untreated group served as control. Following grinding under LN2 and lyophilization, CO(2) (-) radical ions in bone powder were measured by electron paramagnetic resonance spectrometry. We have found that irradiation of bone with G and EB induces formation of enormous amounts of CO(2) (-) radical ions, absent from native tissue. Free radical ion formation was dose-dependent when irradiation was performed at AT, and significantly lower in EB as compared to G-irradiated groups. In contrast, no marked effect of dose was observed when deep-frozen (DI) bone samples were irradiated with G or EB, and free radical ion numbers seemed to be slightly higher in EB-irradiated groups. Irradiation at AT induced much higher quantities of CO(2) (-) radical ions then on DI. That effect was more pronounced in G-irradiated bone specimens, probably due to longer exposure time. Similarly, bone defatting protective effect on free radical ion formation was found only in groups irradiated for several hours with gamma radiation at ambient temperature. Ambient irradiation temperature together with exposure time seem to be key

  4. Temperature dependence of electron magnetic resonance spectra of iron oxide nanoparticles mineralized in Listeria innocua protein cages

    PubMed Central

    Usselman, Robert J.; Russek, Stephen E.; Klem, Michael T.; Allen, Mark A.; Douglas, Trevor; Young, Mark; Idzerda, Yves U.; Singel, David J.

    2012-01-01

    Electron magnetic resonance (EMR) spectroscopy was used to determine the magnetic properties of maghemite (γ-Fe2O3) nanoparticles formed within size-constraining Listeria innocua (LDps)-(DNA-binding protein from starved cells) protein cages that have an inner diameter of 5 nm. Variable-temperature X-band EMR spectra exhibited broad asymmetric resonances with a superimposed narrow peak at a gyromagnetic factor of g ≈ 2. The resonance structure, which depends on both superparamagnetic fluctuations and inhomogeneous broadening, changes dramatically as a function of temperature, and the overall linewidth becomes narrower with increasing temperature. Here, we compare two different models to simulate temperature-dependent lineshape trends. The temperature dependence for both models is derived from a Langevin behavior of the linewidth resulting from “anisotropy melting.” The first uses either a truncated log-normal distribution of particle sizes or a bi-modal distribution and then a Landau-Liftshitz lineshape to describe the nanoparticle resonances. The essential feature of this model is that small particles have narrow linewidths and account for the g ≈ 2 feature with a constant resonance field, whereas larger particles have broad linewidths and undergo a shift in resonance field. The second model assumes uniform particles with a diameter around 4 nm and a random distribution of uniaxial anisotropy axes. This model uses a more precise calculation of the linewidth due to superparamagnetic fluctuations and a random distribution of anisotropies. Sharp features in the spectrum near g ≈ 2 are qualitatively predicted at high temperatures. Both models can account for many features of the observed spectra, although each has deficiencies. The first model leads to a nonphysical increase in magnetic moment as the temperature is increased if a log normal distribution of particles sizes is used. Introducing a bi-modal distribution of particle sizes resolves

  5. Temperature dependence of electron magnetic resonance spectra of iron oxide nanoparticles mineralized in Listeria innocua protein cages

    NASA Astrophysics Data System (ADS)

    Usselman, Robert J.; Russek, Stephen E.; Klem, Michael T.; Allen, Mark A.; Douglas, Trevor; Young, Mark; Idzerda, Yves U.; Singel, David J.

    2012-10-01

    Electron magnetic resonance (EMR) spectroscopy was used to determine the magnetic properties of maghemite (γ-Fe2O3) nanoparticles formed within size-constraining Listeria innocua (LDps)-(DNA-binding protein from starved cells) protein cages that have an inner diameter of 5 nm. Variable-temperature X-band EMR spectra exhibited broad asymmetric resonances with a superimposed narrow peak at a gyromagnetic factor of g ≈ 2. The resonance structure, which depends on both superparamagnetic fluctuations and inhomogeneous broadening, changes dramatically as a function of temperature, and the overall linewidth becomes narrower with increasing temperature. Here, we compare two different models to simulate temperature-dependent lineshape trends. The temperature dependence for both models is derived from a Langevin behavior of the linewidth resulting from "anisotropy melting." The first uses either a truncated log-normal distribution of particle sizes or a bi-modal distribution and then a Landau-Liftshitz lineshape to describe the nanoparticle resonances. The essential feature of this model is that small particles have narrow linewidths and account for the g ≈ 2 feature with a constant resonance field, whereas larger particles have broad linewidths and undergo a shift in resonance field. The second model assumes uniform particles with a diameter around 4 nm and a random distribution of uniaxial anisotropy axes. This model uses a more precise calculation of the linewidth due to superparamagnetic fluctuations and a random distribution of anisotropies. Sharp features in the spectrum near g ≈ 2 are qualitatively predicted at high temperatures. Both models can account for many features of the observed spectra, although each has deficiencies. The first model leads to a nonphysical increase in magnetic moment as the temperature is increased if a log normal distribution of particles sizes is used. Introducing a bi-modal distribution of particle sizes resolves the unphysical

  6. Effects of magnesium deficiency on joint cartilage in immature beagle dogs: immunohistochemistry, electron microscopy, and mineral concentrations.

    PubMed

    Stahlmann, R; Kühner, S; Shakibaei, M; Flores, J; Vormann, J; van Sickle, D C

    2000-01-01

    Quinolone-induced chondrotoxicity is possibly associated with the magnesium-chelating properties of quinolones. This toxic effect seems to be restricted to a rather short time period during postnatal development as shown in rats and dogs. We studied developmental changes of the integrin pattern on canine chondrocytes (e.g. the alpha(v)beta(3)- or alpha(5)beta(1)-integrin), because integrin function depends on divalent cations, as well as the matrix composition (e.g., collagen type II, fibronectin), in 11-, 18-, and 55-week-old Beagles (n=8) by immunohistochemistry. We also analyzed the magnesium and calcium content by atomic absorption spectroscopy in cartilage and bone and studied the effects of a magnesium-deficient diet on joint cartilage in four immature Beagles (18 weeks old at necropsy). The dogs were fed the magnesium-deficient diet for 40 to 46 days. All dogs exhibited gait alterations ('limping') after 4 weeks on the magnesium-deficient diet. Male, magnesium-deficient dogs exhibited pronounced weakness in their front legs; in one of these dogs the front legs were hyperextended to a 90 degrees angle. We observed no significant differences in the integrin pattern in samples from dogs at different developmental stages or in magnesium-deficient dogs in comparison to age-matched controls. Localization of fibronectin in the joint cartilage was found to vary with the age of the dogs as well as with the site of collection. In the middle zone of immature joint cartilage, corresponding to the predilective site of quinolone-induced cartilage lesions, we observed a slight increase in staining with the fibronectin antibody in some samples from magnesium-deficient dogs. Electron microscopy revealed alterations in chondrocytes from the magnesium-deficient dogs (e.g., swollen mitochondria and enlarged endoplasmic reticulum) which are also seen after treatment with quinolones. In summary, we found no significant differences of the integrin pattern on chondrocytes from

  7. Coherent terahertz radiation from high-harmonic component of modulated free-electron beam in a tapered two-asymmetric grating structure

    SciTech Connect

    Zhang Yaxin; Zhou Yucong; Dong Liang; Liu Shenggang

    2012-09-17

    Based on the mechanism of incoherent diffraction radiation excited by an electron bunch in a waveguide with periodic structure, this paper presents the concept of coherent terahertz (THz) radiation from the high-harmonic component of a modulated free-electron beam in a tapered two-asymmetric grating structure. The results show that in this mechanism 0.43 THz radiation can be generated with 10 A/cm{sup 2} current density, and the efficiency can reach 0.5%. Because of the low required current density and relative high efficiency, this concept shows the application potential for electron-beam-driven terahertz sources.

  8. On the relation between the electron content of the ionospheric D-region, variations of the riometer absorption, and the H-component of the geomagnetic field

    NASA Technical Reports Server (NTRS)

    Zelenkova, L. V.; Soldatov, V. A.; Arkhipov, J. V.; Laikova, V. F.

    1989-01-01

    The correlation between lower ionosphere disturbances, geomagnetic variations and radiowave absorption is an important geophysical problem. The correlation is investigated between the electron density profile structure and riometer absorption, and between the absorption and the H-component magnetic field, in order to determine the relation between the (e)-profile parameters and the geomagnetic field variations.

  9. Hygroscopic properties of large aerosol particles using the example of aged Saharan mineral dust - a semi-automated electron microscopy approach

    NASA Astrophysics Data System (ADS)

    Hartmann, Markus; Heim, Lars-Oliver; Ebert, Martin; Weinbruch, Stephan; Kandler, Konrad

    2015-04-01

    Hygroscopic properties of large aerosol particles using the example of aged Saharan mineral dust - a semi-automated electron microscopy approach Markus Hartmann(1), Lars-Oliver Heim(2), Martin Ebert(1), Stephan Weinbruch(1), Konrad Kandler(1) The Saharan Aerosol Long-range Transport and Aerosol-Cloud-Interaction Experiment (SALTRACE) took place at Barbados from June 10 to July 15 2013. During this period, dust was frequently transported from Africa across the Atlantic Ocean toward the Caribbean. In this study, we investigate the atmospheric aging of the dust aerosol based on its hygroscopicity. Aerosol samples were collected ground-based at Ragged Point (13°9'54.4"N, 59°25'55.7"W) with a single round jet cascade impactor on nickel-substrates. The particles from the stage with a 50% efficiency cutoff size of 1 µm were analyzed with an Environmental Scanning Electron Microscope (ESEM) equipped with an energy-dispersive X-ray detector (EDX) and a cooling stage. In an initial automated run, information on particle size and chemical composition for elements heavier than carbon were gathered. Afterwards, electron microscope images of the same sample areas as before were taken during a stepwise increase of relative humidities (between 50 % and 92%), so that the hygroscopic growth of the droplets could be directly observed. The observed hygroscopic growth can be correlated to the chemical composition of the respective particles. For the automated analysis of several hundred images of droplets an image processing algorithm in Python was developed. The algorithm is based on histogram equalization and watershed segmentation. Since SEM images can only deliver two-dimensional information, but the hygroscopic growth factor usually refers to the volume of a drop, Atomic Force Microscopy (AFM) was used to derive an empirical function for the drop volume depending on the apparent drop diameter in the electron images. Aside from the mineral dust, composed of mostly silicates and

  10. Clay Minerals: Adsorbophysical Properties

    NASA Astrophysics Data System (ADS)

    Kotova, O.

    2013-12-01

    The structure and features of surfaces of clay minerals (kaolin, montmorillonite, etc) have an important scientific and practical value. On the surface the interrelation of processes at electronic, atomic and molecular levels is realized. Availability of mineral surface to external influences opens wide scientific and technical opportunities of use of the surface phenomena, so the research of crystal-chemical and crystal-physical processes in near-surface area of clay minerals is important. After long term researches of gas-clay mineral system in physical fields the author has obtained experimental and theoretical material contributing to the creation of the surface theory of clays. A part of the researches is dedicated to studying the mechanism of crystal-chemical and crystal-physical processes in near surface area of clay mineral systems, selectivity of the surface centers to interact with gas phase molecules and adsorbophysical properties. The study of physical and chemical properties of fine clay minerals and their modification has a decisive importance for development of theory and practice of nanotechnologies: they are sorbents, membranes, ceramics and other materials with required electronic features.

  11. Evaluation of sealing ability of Biodentine™ and mineral trioxide aggregate in primary molars using scanning electron microscope: A randomized controlled in vitro trial

    PubMed Central

    Samuel, Allwyn; Asokan, Sharath; Geetha Priya, P. R.; Thomas, Seby

    2016-01-01

    Objective: The aim of this study was to compare the sealing ability of mineral trioxide aggregate (MTA) and Biodentine™ when used to repair the furcal perforations in primary molars using scanning electron microscope (SEM). Study Design: The study sample comprised forty recently extracted primary molars. These teeth were placed in a 5.25% sodium hypochlorite solution for 24 h and washed with tap water. Access cavities were made using a round bur in high-speed handpiece. Perforations were made in the center of the floor of the pulpal chamber using a 0.5 mm round bur. The teeth were randomly assigned into two experimental groups based on the material used to seal the perforation: Group A – MTA and Group B – Biodentine™. The packed materials were allowed to set for 24 h. The samples were sectioned longitudinally and the extent of marginal adaptation was measured by SEM. Wilcoxon-signed rank test was used for statistical analysis using SPSS software. Results: All teeth exhibited microleakage, but Biodentine™ showed significantly less leakage (0.149) compared to MTA (0.583). Conclusion: Based on the results of this study, Biodentine™ showed lesser microleakage compared to MTA and thus may be a good alternative to MTA. PMID:27630495

  12. Effect of bleaching agents having a neutral pH on the surface of mineral trioxide aggregate using electron microscopy and energy dispersive X-ray microanalysis

    PubMed Central

    Kazia, Nooh; Suvarna, Nithin; Shetty, Harish Kumar; Kumar, Pradeep

    2016-01-01

    Aim: To investigate the effect of bleaching agents having a neutral pH on the surface of mineral trioxide aggregate (MTA) used as a coronal seal material for nonvital bleaching, beneath the bleaching agent, with the help of energy dispersive X-ray microanalysis and scanning electron microscopy (SEM). Materials and Methods: Six samples of plastic tubes filled with white MTA (Angelus white) were kept in 100% humidity for 21 days. Each sample was divided into 2 and made into 12 samples. These were then divided into three groups. Group A was exposed to Opalescence Boost 40% hydrogen peroxide (HP) (Ultradent). Group B to Opalescence 10% carbamide peroxide (Ultradent) and Group C (control group) not exposed to any bleaching agent. After recommended period of exposure to bleaching agents according to manufacturers’ instructions, the samples were observed under SEM with an energy dispersive X-ray microanalysis system (JSM-6380 LA). Results: There were no relevant changes in color and no statistically significant surface structure changes of the MTA in both the experimental groups. Conclusion: The present findings suggest that even high concentration HP containing bleaching agents with neutral pH can be used on the surface of MTA without causing structural changes. The superior sealing ability of MTA and the high alkalinity would prevent cervical resorption postbleaching.

  13. Effect of bleaching agents having a neutral pH on the surface of mineral trioxide aggregate using electron microscopy and energy dispersive X-ray microanalysis

    PubMed Central

    Kazia, Nooh; Suvarna, Nithin; Shetty, Harish Kumar; Kumar, Pradeep

    2016-01-01

    Aim: To investigate the effect of bleaching agents having a neutral pH on the surface of mineral trioxide aggregate (MTA) used as a coronal seal material for nonvital bleaching, beneath the bleaching agent, with the help of energy dispersive X-ray microanalysis and scanning electron microscopy (SEM). Materials and Methods: Six samples of plastic tubes filled with white MTA (Angelus white) were kept in 100% humidity for 21 days. Each sample was divided into 2 and made into 12 samples. These were then divided into three groups. Group A was exposed to Opalescence Boost 40% hydrogen peroxide (HP) (Ultradent). Group B to Opalescence 10% carbamide peroxide (Ultradent) and Group C (control group) not exposed to any bleaching agent. After recommended period of exposure to bleaching agents according to manufacturers’ instructions, the samples were observed under SEM with an energy dispersive X-ray microanalysis system (JSM-6380 LA). Results: There were no relevant changes in color and no statistically significant surface structure changes of the MTA in both the experimental groups. Conclusion: The present findings suggest that even high concentration HP containing bleaching agents with neutral pH can be used on the surface of MTA without causing structural changes. The superior sealing ability of MTA and the high alkalinity would prevent cervical resorption postbleaching. PMID:27656061

  14. Evaluation of sealing ability of Biodentine™ and mineral trioxide aggregate in primary molars using scanning electron microscope: A randomized controlled in vitro trial

    PubMed Central

    Samuel, Allwyn; Asokan, Sharath; Geetha Priya, P. R.; Thomas, Seby

    2016-01-01

    Objective: The aim of this study was to compare the sealing ability of mineral trioxide aggregate (MTA) and Biodentine™ when used to repair the furcal perforations in primary molars using scanning electron microscope (SEM). Study Design: The study sample comprised forty recently extracted primary molars. These teeth were placed in a 5.25% sodium hypochlorite solution for 24 h and washed with tap water. Access cavities were made using a round bur in high-speed handpiece. Perforations were made in the center of the floor of the pulpal chamber using a 0.5 mm round bur. The teeth were randomly assigned into two experimental groups based on the material used to seal the perforation: Group A – MTA and Group B – Biodentine™. The packed materials were allowed to set for 24 h. The samples were sectioned longitudinally and the extent of marginal adaptation was measured by SEM. Wilcoxon-signed rank test was used for statistical analysis using SPSS software. Results: All teeth exhibited microleakage, but Biodentine™ showed significantly less leakage (0.149) compared to MTA (0.583). Conclusion: Based on the results of this study, Biodentine™ showed lesser microleakage compared to MTA and thus may be a good alternative to MTA.

  15. Industrial Minerals.

    ERIC Educational Resources Information Center

    Brady, Lawrence L.

    1983-01-01

    Discusses trends in and factors related to the production of industrial minerals during 1982, indicating that, as 1981 marked a downturn in production of industrial minerals, 1982 continued the trend with temporary and permanent cutbacks in mine and plant production. Includes highlights of several conferences/conference papers in this field.…

  16. Organo-mineral interactions in Pseudomonas putida-birnessite assemblages: Impact on mineral reactivity

    NASA Astrophysics Data System (ADS)

    Simanova, Anna; Kroll, Alexandra; Pena, Jasquelin

    2016-04-01

    The ability of microorganisms to precipitate biogenic birnessite nanoparticles is widely spread in the bacterial and fungal trees of life, with this process accounting largely for the formation of birnessite in nature. Birnessite minerals occur typically as nanoparticles that exhibit significant chemical and structural disorder. Furthermore, the mineral is embedded within a biomass matrix composed of microbial cells and extracellular polymeric substances, where the biomass not only provides reactive surfaces but can mediate electron transfer reactions. The overarching question guiding our research is: How do nanoscale properties and admixing with microbial biomass modify the reactivity of Mn oxide minerals? In this study, we investigate the biomass-birnessite composites of Pseudomonas putida GB-1 biomass and δ-MnO2 nanoparticles. We characterized the structure and composition of the mineral fraction using X-ray diffraction, Mn K-edge X-ray absorption spectroscopy and wet-chemical methods. To characterize the biomass fraction, we employed FTIR spectroscopy and size-exclusion chromatography analysis of the extracellular polymeric substances. Finally, we measured Ni(II) sorption isotherms at pH 6 and Ni K-edge EXAFS spectra to determine the extent and mechanism of Ni sorption in the biomass-mineral composites and in biomass-only and mineral-only systems. This approach provided direct and indirect evidence for the extent of organo-mineral interactions in the composites, as well as a direct measure of sorption reactivity in the composites relative to biomass-only and mineral-only systems. We found that admixing of mineral nanoparticles with biomass reduced the reactivity of the edge sites of birnessite particles towards Ni(II) through the attachment of organic moieties to the mineral particles and/or modification of the assemblage surface charge properties. In addition, the interaction of biomass components with MnO2 particles leads to partial Mn(IV) reduction and

  17. Microwave measurement test results of circular waveguide components for electron cyclotron resonant heating (ECRH) of the Tandem Mirror Experiment-Upgrade (TMX-U)

    SciTech Connect

    Williams, C.W.; Rubert, R.R.; Coffield, F.E.; Felker, B.; Stallard, B.W.; Taska, J.

    1983-12-01

    Development of high-power components for electron cyclotron resonant heating (ECRH) applications requires extensive testing. In this paper we describe the high-power testing of various circular waveguide components designed for application on the Tandem Mirror Experiment-Upgrade (TMX-U). These include a 2.5-in. vacuum valve, polarizing reflectors, directional couplers, mode converters, and flexible waveguides. All of these components were tested to 200 kW power level with 40-ms pulses. Cold tests were used to determine field distribution. The techniques used in these tests are illustrated. The new high-power test facility at Lawrence Livermore National Laboratory (LLNL) is described and test procedures are discussed. We discuss the following test results: efficiency at high power of mode converters, comparison of high power vs low power for waveguide components, and full power tests of the waveguide system. We also explain the reasons behind selection of these systems for use on TMX-U.

  18. Observation of nitrate coatings on atmospheric mineral dust particles

    NASA Astrophysics Data System (ADS)

    Li, W. J.; Shao, L. Y.

    2009-03-01

    Nitrate compounds have received much attention because of their ability to alter the hygroscopic properties and cloud condensation nuclei (CCN) activity of mineral dust particles in the atmosphere. However, very little is known about specific characteristics of ambient nitrate-coated mineral particles on an individual particle scale. In this study, sample collection was conducted during brown haze and dust episodes between 24 May and 21 June 2007 in Beijing, northern China. Sizes, morphologies, and compositions of 332 mineral dust particles together with their coatings were analyzed using transmission electron microscopy (TEM) coupled with energy-dispersive X-ray (EDX) microanalyses. Structures of some mineral particles were verified using selected-area electron diffraction (SAED). TEM observation indicates that approximately 90% of the collected mineral particles are covered by visible coatings in haze samples whereas only 5% are coated in the dust sample. 92% of the analyzed mineral particles are covered with Ca-, Mg-, and Na-rich coatings, and 8% are associated with K- and S-rich coatings. The majority of coatings contain Ca, Mg, O, and N with minor amounts of S and Cl, suggesting that they are possibly nitrates mixed with small amounts of sulfates and chlorides. These nitrate coatings are strongly correlated with the presence of alkaline mineral components (e.g., calcite and dolomite). CaSO4 particles with diameters from 10 to 500 nm were also detected in the coatings including Ca(NO3)2 and Mg(NO3)2. Our results indicate that mineral particles in brown haze episodes were involved in atmospheric heterogeneous reactions with two or more acidic gases (e.g., SO2, NO2, HCl, and HNO3). Mineral particles that acquire hygroscopic nitrate coatings tend to be more spherical and larger, enhancing their light scattering and CCN activity, both of which have cooling effects on the climate.

  19. Mineral Commodity Summaries 2010

    USGS Publications Warehouse

    ,

    2010-01-01

    International Strategic Minerals Inventory) are the basis for some reserves estimates. The USGS collects information about the quantity and quality of mineral resources but does not directly measure reserves, and companies or governments do not directly report reserves to the USGS. Reassessment of reserves is a continuing process, and the intensity of this process differs for mineral commodities, countries, and time period. Throughout the history of Mineral Commodity Summaries and its predecessor prior to 1978, Commodity Data Summaries, the presentation of resource data has evolved. Although world resources have been discussed each year, presentation of reserves and reserve base data varied. From 1957 through 1979, only reserves information was published in the reports, but from 1980 through 1987, only estimates of reserve base, a concept introduced by the U.S. Bureau of Mines (USBM) and the USGS in 1980, were published. Beginning in 1988, both reserves and reserve base information were listed for each mineral commodity where applicable and available. Prior to 1996, the minerals availability studies conducted by the USBM and work with international collaborators were the basis for reserve base data reported in Mineral Commodity Summaries. When the USBM was closed in 1996, this function was discontinued. Since that time, reserve base estimates have been updated to be consistent with changes in reserves, but the nonreserves component of the information upon which the reserve base data were estimated is not current enough to support defensible reserve base estimates. For that reason, publication of reserve base estimates was discontinued for Mineral Commodity Summaries 2010. Abbreviations and units of measure, and definitions of selected terms used in the report, are in Appendix A and Appendix B, respectively. A resource/reserve classification for minerals, based on USGS Circular 831 (published with the U.S. Bureau of Mines) is Appendix C, and a directory of USGS minerals

  20. Component-Level Electronic-Assembly Repair (CLEAR) Analysis of the Problem Reporting and Corrective Action (PRACA) Database of the International Space Station On-Orbit Electrical Systems

    NASA Technical Reports Server (NTRS)

    Oeftering, Richard C.; Bradish, Martin A.; Juergens, Jeffrey R.; Lewis, Michael J.

    2011-01-01

    The NASA Constellation Program is investigating and developing technologies to support human exploration of the Moon and Mars. The Component-Level Electronic-Assembly Repair (CLEAR) task is part of the Supportability Project managed by the Exploration Technology Development Program. CLEAR is aimed at enabling a flight crew to diagnose and repair electronic circuits in space yet minimize logistics spares, equipment, and crew time and training. For insight into actual space repair needs, in early 2008 the project examined the operational experience of the International Space Station (ISS) program. CLEAR examined the ISS on-orbit Problem Reporting and Corrective Action database for electrical and electronic system problems. The ISS has higher than predicted reliability yet, as expected, it has persistent problems. A goal was to identify which on-orbit electrical problems could be resolved by a component-level replacement. A further goal was to identify problems that could benefit from the additional diagnostic and test capability that a component-level repair capability could provide. The study indicated that many problems stem from a small set of root causes that also represent distinct component problems. The study also determined that there are certain recurring problems where the current telemetry instrumentation and built-in tests are unable to completely resolve the problem. As a result, the root cause is listed as unknown. Overall, roughly 42 percent of on-orbit electrical problems on ISS could be addressed with a component-level repair. Furthermore, 63 percent of on-orbit electrical problems on ISS could benefit from additional external diagnostic and test capability. These results indicate that in situ component-level repair in combination with diagnostic and test capability can be expected to increase system availability and reduce logistics. The CLEAR approach can increase the flight crew s ability to act decisively to resolve problems while reducing

  1. Korteweg-deVries-Burgers (KdVB) equation in a five component cometary plasma with kappa described electrons and ions

    NASA Astrophysics Data System (ADS)

    Michael, Manesh; Willington, Neethu T.; Jayakumar, Neethu; Sebastian, Sijo; Sreekala, G.; Venugopal, Chandu

    2016-07-01

    We investigate the existence of ion-acoustic shock waves in a five component cometary plasma consisting of positively and negatively charged oxygen ions, kappa described hydrogen ions, hot solar electrons, and slightly colder cometary electrons. The KdVB equation has been derived for the system, and its solution plotted for different kappa values, oxygen ion densities, as well as the temperature ratios for the ions. It is found that the amplitude of the shock wave decreases with increasing kappa values. The strength of the shock profile decreases with increasing temperatures of the positively charged oxygen ions and densities of negatively charged oxygen ions.

  2. Effect of acid etching on marginal adaptation of mineral trioxide aggregate to apical dentin: microcomputed tomography and scanning electron microscopy analysis.

    PubMed

    Al-Fouzan, Khalid; Al-Garawi, Ziad; Al-Hezaimi, Khalid; Javed, Fawad; Al-Shalan, Thakib; Rotstein, Ilan

    2012-12-01

    The present investigation assessed the effect of acid etching on marginal adaptation of white- and gray-colored mineral trioxide aggregate (MTA) to apical dentin using microcomputed tomography (micro-CT) and scanning electron microscopy (SEM). Sixty-four extracted single-rooted human maxillary teeth were used. Following root-end resection and apical preparation, the teeth were equally divided into four groups according to the following root end filling materials: (i) white-colored MTA (WMTA), (ii) etched WMTA (EWMTA), (iii) gray-colored MTA (GMTA) and (iv) etched GMTA (EGMTA). After 48 h, the interface between root-end filling materials and the dentinal walls was assessed using micro-CT and SEM. Data were statistically analyzed using the Kruskal-Wallis and Dunn tests. Micro-CT analysis revealed gap volumes between the apical cavity dentin walls and EGMTA, GMTA, EWMTA and WMTA of (0.007 1±0.004) mm(3), (0.053±0.002) mm(3), (0.003 6±0.001) mm(3) and (0.005 9±0.002) mm(3) respectively. SEM analysis revealed gap sizes for EGMTA, WMTA, EWMTA and GMTA to be (492.3±13.8) µm, (594.5±17.12) µm, (543.1±15.33) µm and (910.7±26.2) µm respectively. A significant difference in gap size between root end preparations filled with GMTA and EGMTA was found (P<0.05). No significance difference in gap size between WMTA and EWMTA were found in either SEM or micro-CT analysis. In conclusion, pre-etching of apical dentin can provide a better seal for GMTA but not for WMTA. PMID:23306857

  3. Comparing the Marginal Adaptation of Cold Ceramic and Mineral Trioxide Aggregate by Means of Scanning Electron Microscope: An In vitro Study

    PubMed Central

    Mokhtari, Fatemeh; Modaresi, Jalil; Javadi, Gholamreza; Davoudi, Amin; Badrian, Hamid

    2015-01-01

    Background: Long-term success of endodontic surgeries is often influenced by the type of root-end filling material (RFM). The aim of present study was to compare the marginal adaptation of two different RFM, cold ceramic (CC) and mineral trioxide aggregate (MTA), using scanning electron microscope (SEM). Materials and Methods: About 20 extracted human single-rooted teeth were collected and stored into sodium hypochlorite 5.25%. The teeth were decronated from the cemento-enamel junction to prepare 16 mm roots. The working length was measured, and 1/3 coronal of the canal was prepared by Gates-Glidden drills. Apical flaring was followed by K file size # 40-70 based on step back technique. After filling of the canals, 3 mm above the apex was cut at 90° to the long axis. Furthermore, 3 mm of the filling was removed from the apical part using the ultrasonic device. All of the prepared specimens were divided into two groups and were retro filled by MTA and CC. The roots were cut horizontally from 1 mm above the apical part, and dentin-filling material interface was observed by SEM. Finally, the collected data were analyzed by Mann-Whitney test and using SPSS software version 18 at a significant level of 0.05. Results: The mean interfacial adaptation was higher in CC group. However, no significant differences were observed by statistical test (P = 0.35). Conclusion: Both CC and MTA had similar marginal adaptation as RFM however in vivo studies are recommended for better determination. PMID:26435608

  4. COMPONENTS OF LASER SYSTEMS: Pumping of the GARPUN wide-aperture excimer laser by counterpropagating electron beams

    NASA Astrophysics Data System (ADS)

    Arlantsev, S. V.; Grigor'yants, E. A.; Vadkovskii, A. D.; Zvorykin, V. D.; Metreveli, G. E.

    1994-03-01

    The transport of high-current electron beams from vacuum diodes to the laser chamber of the GARPUN wide-aperture excimer laser was investigated experimentally and theoretically. The processes involving the transport of fast electrons in argon and krypton in a longitudinal magnetic field were also studied. Pumping by counter-propagating electron beams resulted in the deposition of up to 2.1 kJ of energy into the active medium of the laser, which corresponded to a specific excitation power of ~0.8 MW cm-3 with an inhomogeneity of less than 20% over a 12 cm × 18 cm aperture. The efficiency of the energy deposition by electron beams was ~60% and the overall efficiency of the laser pumping system was ~16%.

  5. Mineral Quantification.

    PubMed

    2016-01-01

    Optimal intakes of elements, such as sodium, potassium, magnesium, calcium, manganese, copper, zinc and iodine, can reduce individual risk factors including those related to cardiovascular diseases among humans and animals. In order to meet the need for vitamins, major minerals, trace minerals, fatty acids and amino acids, it is necessary to include a full spectrum programme that can deliver all of the nutrients in the right ratio. Minerals are required for normal growth, activities of muscles, skeletal development (such as calcium), cellular activity, oxygen transport (copper and iron), chemical reactions in the body, intestinal absorption (magnesium), fluid balance and nerve transmission (sodium and potassium), as well as the regulation of the acid base balance (phosphorus). The chapter discusses the chemical and instrumentation techniques used for estimation of minerals such as N, P, Ca, Mg, K, Na, Fe, Cu, Zn, B and Mb. PMID:26939263

  6. Mineral Quantification.

    PubMed

    2016-01-01

    Optimal intakes of elements, such as sodium, potassium, magnesium, calcium, manganese, copper, zinc and iodine, can reduce individual risk factors including those related to cardiovascular diseases among humans and animals. In order to meet the need for vitamins, major minerals, trace minerals, fatty acids and amino acids, it is necessary to include a full spectrum programme that can deliver all of the nutrients in the right ratio. Minerals are required for normal growth, activities of muscles, skeletal development (such as calcium), cellular activity, oxygen transport (copper and iron), chemical reactions in the body, intestinal absorption (magnesium), fluid balance and nerve transmission (sodium and potassium), as well as the regulation of the acid base balance (phosphorus). The chapter discusses the chemical and instrumentation techniques used for estimation of minerals such as N, P, Ca, Mg, K, Na, Fe, Cu, Zn, B and Mb.

  7. Higher-order contributions to ion-acoustic solitary waves in a multicomponent plasma consisting of warm ions and two-component nonisothermal electrons

    SciTech Connect

    Das, K.P.; Majumdar, S.R.; Paul, S.N. ||

    1995-05-01

    An integrated form of the governing equations in terms of pseudopotential higher-order nonlinear and dispersive effects is obtained by applying the reductive perturbation method for ion-acoustic solitary waves in a collisionless unmagnetized multicomponent plasma having warm ions and two-component nonisothermal electrons. The present method is advantageous because instead of solving an inhomogeneous second-order differential equation at each order, as in the standard procedure, we solve a first-order inhomogeneous equation at each order except at the lowest. The expressions of both Mach number and width of the solitary wave are obtained as a function of the amplitude of the wave for third-order nonlinear and dispersive effects. The variations of potential, width, and Mach number against soliton amplitude are shown graphically, taking into consideration the nonisothermality of two-component electrons in the plasma.

  8. The Space Radiation Environment as it Relates to Electronic System Performance: Or Why Not to Fly Commercial Electronic Components in Space

    NASA Technical Reports Server (NTRS)

    Barth, Janet L.; Xapsos, Michael A.; LaBel, Kenneth A.; Polvey, Christian

    2005-01-01

    This viewgraph presentation offers an overview of the space radiation environment, primarily in near-Earth environments such as Low Earth Orbit (LEO). The presentation describes the Halloween solar event of 2003 as an example of how solar activity can affect spacecraft electronic systems. The lunar radiation environment is also briefly summarized.

  9. Nanographenes as active components of single-molecule electronics and how a scanning tunneling microscope puts them to work.

    PubMed

    Müllen, Klaus; Rabe, Jürgen P

    2008-04-01

    Single-molecule electronics, that is, realizing novel electronic functionalities from single (or very few) molecules, holds promise for application in various technologies, including signal processing and sensing. Nanographenes, which are extended polycyclic aromatic hydrocarbons (PAHs), are highly attractive subjects for studies of single-molecule electronics because the electronic properties of their flat conjugated systems can be varied dramatically through synthetic modification of their sizes and topologies. Single nanographenes provide high tunneling currents when adsorbed flat onto conducting substrates, such as graphite. Because of their chemical inertness, nanographenes interact only weakly with these substrates, thereby preventing the need for special epitaxial structure matching. Instead, self-assembly at the interface between a conducting solid, such as the basal plane of graphite, and a nanographene solution generally leads to highly ordered monolayers. Scanning tunneling spectroscopy (STS) allows the current-voltage characteristics to be measured through a single molecule positioned between two electrodes; the key to the success of STS is the ability to position the scanning tunneling microscopy (STM) tip freely with respect to the molecule in all dimensions, that is, both parallel and perpendicular to the surface. In this Account, we report the properties of nanographenes having sizes ranging from 0.7 to 3.1 nm and exhibiting various symmetry, periphery, and substitution types. The size of the aromatic system and the nature of its perimeter are two essential features affecting its HOMO-LUMO gap and charge carrier mobility in the condensed phase. Moreover, the extended pi area of larger substituted PAHs improves the degree of self-ordering, another key requirement for high-performance electronic devices. Self-assembly at the interface between an organic solution and the basal plane of graphite allows deposition of single molecules within the well

  10. Iron oxyhydroxide mineralization on microbial extracellular polysaccharides

    NASA Astrophysics Data System (ADS)

    Chan, Clara S.; Fakra, Sirine C.; Edwards, David C.; Emerson, David; Banfield, Jillian F.

    2009-07-01

    Iron biominerals can form in neutral pH microaerophilic environments where microbes both catalyze iron oxidation and create polymers that localize mineral precipitation. In order to classify the microbial polymers that influence FeOOH mineralogy, we studied the organic and mineral components of biominerals using scanning transmission X-ray microscopy (STXM), micro X-ray fluorescence (μXRF) microscopy, and high-resolution transmission electron microscopy (HRTEM). We focused on iron microbial mat samples from a creek and abandoned mine; these samples are dominated by iron oxyhydroxide-coated structures with sheath, stalk, and filament morphologies. In addition, we characterized the mineralized products of an iron-oxidizing, stalk-forming bacterial culture isolated from the mine. In both natural and cultured samples, microbial polymers were found to be acidic polysaccharides with carboxyl functional groups, strongly spatially correlated with iron oxyhydroxide distribution patterns. Organic fibrils collect FeOOH and control its recrystallization, in some cases resulting in oriented crystals with high aspect ratios. The impact of polymers is particularly pronounced as the materials age. Synthesis experiments designed to mimic the biomineralization processes show that the polysaccharide carboxyl groups bind dissolved iron strongly but release it as mineralization proceeds. Our results suggest that carboxyl groups of acidic polysaccharides are produced by different microorganisms to create a wide range of iron oxyhydroxide biomineral structures. The intimate and potentially long-term association controls the crystal growth, phase, and reactivity of iron oxyhydroxide nanoparticles in natural systems.

  11. Iron oxyhydroxide mineralization on microbial extracellular polysaccharides

    SciTech Connect

    Chan, Clara S.; Fakra, Sirine C.; Edwards, David C.; Emerson, David; Banfield, Jillian F.

    2010-06-22

    Iron biominerals can form in neutral pH microaerophilic environments where microbes both catalyze iron oxidation and create polymers that localize mineral precipitation. In order to classify the microbial polymers that influence FeOOH mineralogy, we studied the organic and mineral components of biominerals using scanning transmission X-ray microscopy (STXM), micro X-ray fluorescence ({mu}XRF) microscopy, and high-resolution transmission electron microscopy (HRTEM). We focused on iron microbial mat samples from a creek and abandoned mine; these samples are dominated by iron oxyhydroxide-coated structures with sheath, stalk, and filament morphologies. In addition, we characterized the mineralized products of an iron-oxidizing, stalk-forming bacterial culture isolated from the mine. In both natural and cultured samples, microbial polymers were found to be acidic polysaccharides with carboxyl functional groups, strongly spatially correlated with iron oxyhydroxide distribution patterns. Organic fibrils collect FeOOH and control its recrystallization, in some cases resulting in oriented crystals with high aspect ratios. The impact of polymers is particularly pronounced as the materials age. Synthesis experiments designed to mimic the biomineralization processes show that the polysaccharide carboxyl groups bind dissolved iron strongly but release it as mineralization proceeds. Our results suggest that carboxyl groups of acidic polysaccharides are produced by different microorganisms to create a wide range of iron oxyhydroxide biomineral structures. The intimate and potentially long-term association controls the crystal growth, phase, and reactivity of iron oxyhydroxide nanoparticles in natural systems.

  12. The Diesel Exhaust in Miners Study: III. Interrelations between Respirable Elemental Carbon and Gaseous and Particulate Components of Diesel Exhaust derived from Area Sampling in Underground Non-metal Mining Facilities

    PubMed Central

    Vermeulen, Roel; Coble, Joseph B.; Yereb, Daniel; Lubin, Jay H.; Blair, Aaron; Portengen, Lützen; Stewart, Patricia A.; Attfield, Michael; Silverman, Debra T.

    2010-01-01

    Diesel exhaust (DE) has been implicated as a potential lung carcinogen. However, the exact components of DE that might be involved have not been clearly identified. In the past, nitrogen oxides (NOx) and carbon oxides (COx) were measured most frequently to estimate DE, but since the 1990s, the most commonly accepted surrogate for DE has been elemental carbon (EC). We developed quantitative estimates of historical exposure levels of respirable elemental carbon (REC) for an epidemiologic study of mortality, particularly lung cancer, among diesel-exposed miners by back-extrapolating 1998–2001 REC exposure levels using historical measurements of carbon monoxide (CO). The choice of CO was based on the availability of historical measurement data. Here, we evaluated the relationship of REC with CO and other current and historical components of DE from side-by-side area measurements taken in underground operations of seven non-metal mining facilities. The Pearson correlation coefficient of the natural log-transformed (Ln)REC measurements with the Ln(CO) measurements was 0.4. The correlation of REC with the other gaseous, organic carbon (OC), and particulate measurements ranged from 0.3 to 0.8. Factor analyses indicated that the gaseous components, including CO, together with REC, loaded most strongly on a presumed ‘Diesel exhaust’ factor, while the OC and particulate agents loaded predominantly on other factors. In addition, the relationship between Ln(REC) and Ln(CO) was approximately linear over a wide range of REC concentrations. The fact that CO correlated with REC, loaded on the same factor, and increased linearly in log–log space supported the use of CO in estimating historical exposure levels to DE. PMID:20876234

  13. Stability of hybrid modes of a single-component electron plasma containing an admixture of background gas ions

    NASA Astrophysics Data System (ADS)

    Yeliseyev, Yu. N.

    2014-05-01

    The spectrum of eigenmodes of a waveguide completely filled with a cold electron plasma containing a small admixture of ions produced due to electron-impact ionization of background gas atoms is calculated numerically. The calculations were performed within the entire range of allowable values of the radial electric and longitudinal magnetic fields for both magnetized and unmagnetized ions by using the earlier derived nonlocal dispersion relation [Plasma Phys. Rep. 36, 563 (2010)]. The spectrum consists of three families of electron modes with frequencies equal to the Doppler-shifted upper and lower hybrid frequencies and modified ion cyclotron (MIC) modes. When the Doppler shift caused by electron rotation in the crossed electric and magnetic fields compensates for the hybrid frequency, the electron modes become low-frequency modes and interact with the ion modes. For m = 1, only the lower hybrid modes can be low-frequency ones, whereas at m ≥ 2, both lower and upper hybrid modes can be low-frequency ones. The spectrum of modes having the azimuthal number m = 2 is thoroughly analyzed. It is shown that, in this case, the lower hybrid modes behave similar to the m = 1 modes. The dispersion curves of the upper hybrid modes intersect with all harmonics of the MIC frequency (positive, negative, and zero) and are unstable in the vicinities of the intersections. The maximum value of the instability growth rate is several times higher than the ion plasma frequency. The MIC modes are unstable within a wide range of the field strengths, and their growth rates are two orders of magnitude slower. Instabilities are caused by the relative motion of electrons and ions (the transverse current) and the anisotropy of the ion distribution function.

  14. H I free-bound emission of planetary nebulae with large abundance discrepancies: Two-component models versus κ-distributed electrons

    SciTech Connect

    Zhang, Yong; Liu, Xiao-Wei; Zhang, Bing

    2014-01-01

    The 'abundance discrepancy' problem in the study of planetary nebulae (PNe), viz., the problem concerning systematically higher heavy-element abundances derived from optical recombination lines relative to those from collisionally excited lines, has been under discussion for decades, but no consensus on its solution has yet been reached. In this paper, we investigate the hydrogen free-bound emission near the Balmer jump region of four PNe that are among those with the largest abundance discrepancies, aiming to examine two recently proposed solutions to this problem: two-component models and κ electron energy distributions. We find that the Balmer jump intensities and the spectrum slopes cannot be simultaneously matched by the theoretical calculations based upon single Maxwell-Boltzmann electron-energy distributions, whereas the fitting can be equally improved by introducing κ electron energy distributions or an additional Maxwell-Boltzmann component. We show that although H I free-bound emission alone cannot distinguish between the two scenarios, it can provide important constraints on the electron energy distributions, especially for cold and low-κ plasmas.

  15. Connecting the irreversible capacity loss in Li-ion batteries with the electronic insulating properties of solid electrolyte interphase (SEI) components.

    SciTech Connect

    Leung, Kevin; Lin, Yu -Xiao; Liu, Zhe; Chen, Long -Qing; Lu, Peng; Qi, Yue

    2016-01-01

    The formation and continuous growth of a solid electrolyte interphase (SEI) layer are responsible for the irreversible capacity loss of batteries in the initial and subsequent cycles, respectively. In this article, the electron tunneling barriers from Li metal through three insulating SEI components, namely Li2CO3, LiF and Li3PO4, are computed by density function theory (DFT) approaches. Based on electron tunneling theory, it is estimated that sufficient to block electron tunneling. It is also found that the band gap decreases under tension while the work function remains the same, and thus the tunneling barrier decreases under tension and increases under compression. A new parameter, η, characterizing the average distances between anions, is proposed to unify the variation of band gap with strain under different loading conditions into a single linear function of η. An analytical model based on the tunneling results is developed to connect the irreversible capacity loss, due to the Li ions consumed in forming these SEI component layers on the surface of negative electrodes. As a result, the agreement between the model predictions and experimental results suggests that only the initial irreversible capacity loss is due to the self-limiting electron tunneling property of the SEI.

  16. Connecting the irreversible capacity loss in Li-ion batteries with the electronic insulating properties of solid electrolyte interphase (SEI) components.

    DOE PAGES

    Leung, Kevin; Lin, Yu -Xiao; Liu, Zhe; Chen, Long -Qing; Lu, Peng; Qi, Yue

    2016-01-01

    The formation and continuous growth of a solid electrolyte interphase (SEI) layer are responsible for the irreversible capacity loss of batteries in the initial and subsequent cycles, respectively. In this article, the electron tunneling barriers from Li metal through three insulating SEI components, namely Li2CO3, LiF and Li3PO4, are computed by density function theory (DFT) approaches. Based on electron tunneling theory, it is estimated that sufficient to block electron tunneling. It is also found that the band gap decreases under tension while the work function remains the same, and thus the tunneling barrier decreases under tension and increases under compression.more » A new parameter, η, characterizing the average distances between anions, is proposed to unify the variation of band gap with strain under different loading conditions into a single linear function of η. An analytical model based on the tunneling results is developed to connect the irreversible capacity loss, due to the Li ions consumed in forming these SEI component layers on the surface of negative electrodes. As a result, the agreement between the model predictions and experimental results suggests that only the initial irreversible capacity loss is due to the self-limiting electron tunneling property of the SEI.« less

  17. Enantiomer-specific analysis of multi-component mixtures by correlated electron imaging–ion mass spectrometry

    PubMed Central

    Fanood, Mohammad M Rafiee; Ram, N. Bhargava; Lehmann, C. Stefan; Powis, Ivan; Janssen, Maurice H. M.

    2015-01-01

    Simultaneous, enantiomer-specific identification of chiral molecules in multi-component mixtures is extremely challenging. Many established techniques for single-component analysis fail to provide selectivity in multi-component mixtures and lack sensitivity for dilute samples. Here we show how enantiomers may be differentiated by mass-selected photoelectron circular dichroism using an electron–ion coincidence imaging spectrometer. As proof of concept, vapours containing ∼1% of two chiral monoterpene molecules, limonene and camphor, are irradiated by a circularly polarized femtosecond laser, resulting in multiphoton near-threshold ionization with little molecular fragmentation. Large chiral asymmetries (2–4%) are observed in the mass-tagged photoelectron angular distributions. These asymmetries switch sign according to the handedness (R- or S-) of the enantiomer in the mixture and scale with enantiomeric excess of a component. The results demonstrate that mass spectrometric identification of mixtures of chiral molecules and quantitative determination of enantiomeric excess can be achieved in a table-top instrument. PMID:26104140

  18. Efficiency and Loss Models for Key Electronic Components of Hybrid and Plug-in Hybrid Electric Vehicles' Electrical Propulsion Systems

    SciTech Connect

    Cao, J.; Bharathan, D.; Emadi, A.

    2007-01-01

    Isolated gate bipolar transistors (IGBTs) are widely used in power electronic applications including electric, hybrid electric, and plug-in hybrid electric vehicles (EVs, HEVs, and PHEVs). The trend towards more electric vehicles (MEVs) has demanded the need for power electronic devices capable of handling power in the range of 10-100 kW. However, the converter losses in this power range are of critical importance. Therefore, thermal management of the power electronic devices/converters is crucial for the reliability and longevity of the advanced vehicles. To aid the design of heat exchangers for the IGBT modules used in propulsion motor drives, a loss model for the IGBTs is necessary. The loss model of the IGBTs will help in the process of developing new heat exchangers and advanced thermal interface materials by reducing cost and time. This paper deals with the detailed loss modeling of IGBTs for advanced electrical propulsion systems. An experimental based loss model is proposed. The proposed loss calculation method utilizes the experimental data to reconstruct the loss surface of the power electronic devices by means of curve fitting and linear extrapolating. This enables the calculation of thermal losses in different voltage, current, and temperature conditions of operation. To verify the calculation method, an experimental test set-up was designed and built. The experimental set-up is an IGBT based bi-directional DC/DC converter. In addition, simulation results are presented to verify the proposed calculation method.

  19. Higher order nonlinear effects on wave structures in a four-component dusty plasma with nonisothermal electrons

    SciTech Connect

    Singh Gill, Tarsem; Bedi, Chanchal; Saini, Nareshpal Singh

    2011-04-15

    The higher order solutions of dust acoustic wave in dusty plasma consisting of positively charged warm adiabatic dust, negatively charged cold dust, and nonisothermally distributed electrons are studied. The Schamel-KdV equation is derived using reductive perturbation method (RPM). RPM is further extended to include the contributions of higher order terms and a generalized KdV equation is derived to observe the deviation from isothermality. Effects of nonisothermal parameter, mass and charge ratio, ratio of ion to electron temperatures, and ratio of dust to ion temperatures have been thoroughly studied. By using the renormalization method of Kodama and Taniuti [J. Phys. Soc. Jpn. 45, 298 (1978)], authors have also discussed characteristics of the dressed solitons.

  20. Rational engineering of Geobacter sulfurreducens electron transfer components: a foundation for building improved Geobacter-based bioelectrochemical technologies

    PubMed Central

    Dantas, Joana M.; Morgado, Leonor; Aklujkar, Muktak; Bruix, Marta; Londer, Yuri Y.; Schiffer, Marianne; Pokkuluri, P. Raj; Salgueiro, Carlos A.

    2015-01-01

    Multiheme cytochromes have been implicated in Geobacter sulfurreducens extracellular electron transfer (EET). These proteins are potential targets to improve EET and enhance bioremediation and electrical current production by G. sulfurreducens. However, the functional characterization of multiheme cytochromes is particularly complex due to the co-existence of several microstates in solution, connecting the fully reduced and fully oxidized states. Over the last decade, new strategies have been developed to characterize multiheme redox proteins functionally and structurally. These strategies were used to reveal the functional mechanism of G. sulfurreducens multiheme cytochromes and also to identify key residues in these proteins for EET. In previous studies, we set the foundations for enhancement of the EET abilities of G. sulfurreducens by characterizing a family of five triheme cytochromes (PpcA-E). These periplasmic cytochromes are implicated in electron transfer between the oxidative reactions of metabolism in the cytoplasm and the reduction of extracellular terminal electron acceptors at the cell's outer surface. The results obtained suggested that PpcA can couple e−/H+ transfer, a property that might contribute to the proton electrochemical gradient across the cytoplasmic membrane for metabolic energy production. The structural and functional properties of PpcA were characterized in detail and used for rational design of a family of 23 single site PpcA mutants. In this review, we summarize the functional characterization of the native and mutant proteins. Mutants that retain the mechanistic features of PpcA and adopt preferential e−/H+ transfer pathways at lower reduction potential values compared to the wild-type protein were selected for in vivo studies as the best candidates to increase the electron transfer rate of G. sulfurreducens. For the first time G. sulfurreducens strains have been manipulated by the introduction of mutant forms of essential

  1. Rational engineering of Geobacter sulfurreducens electron transfer components: A foundation for building improved Geobacter-based bioelectrochemical technologies

    DOE PAGES

    Dantas, Joana M.; Morgado, Leonor; Aklujkar, Muktak; Bruix, Marta; Londer, Yuri Y.; Schiffer, Marianne; Pokkuluri, P. Raj; Salgueiro, Carlos A.

    2015-07-30

    Multiheme cytochromes have been implicated in Geobacter sulfurreducens extracellular electron transfer (EET). These proteins are potential targets to improve EET and enhance bioremediation and electrical current production by G. sulfurreducens. However, the functional characterization of multiheme cytochromes is particularly complex due to the co-existence of several microstates in solution, connecting the fully reduced and fully oxidized states. Throughout the last decade, new strategies have been developed to characterize multiheme redox proteins functionally and structurally. These strategies were used to reveal the functional mechanism of G. sulfurreducens multiheme cytochromes and also to identify key residues in these proteins for EET. Inmore » previous studies, we set the foundations for enhancement of the EET abilities of G. sulfurreducens by characterizing a family of five triheme cytochromes (PpcA-E). These periplasmic cytochromes are implicated in electron transfer between the oxidative reactions of metabolism in the cytoplasm and the reduction of extracellular terminal electron acceptors at the cell's outer surface. The results obtained suggested that PpcA can couple e-/H+ transfer, a property that might contribute to the proton electrochemical gradient across the cytoplasmic membrane for metabolic energy production. The structural and functional properties of PpcA were characterized in detail and used for rational design of a family of 23 single site PpcA mutants. In this review, we summarize the functional characterization of the native and mutant proteins. Mutants that retain the mechanistic features of PpcA and adopt preferential e-/H+ transfer pathways at lower reduction potential values compared to the wild-type protein were selected for in vivo studies as the best candidates to increase the electron transfer rate of G. sulfurreducens. For the first time G. sulfurreducens strains have been manipulated by the introduction of mutant forms of

  2. Rational engineering of Geobacter sulfurreducens electron transfer components: a foundation for building improved Geobacter-based bioelectrochemical technologies.

    PubMed

    Dantas, Joana M; Morgado, Leonor; Aklujkar, Muktak; Bruix, Marta; Londer, Yuri Y; Schiffer, Marianne; Pokkuluri, P Raj; Salgueiro, Carlos A

    2015-01-01

    Multiheme cytochromes have been implicated in Geobacter sulfurreducens extracellular electron transfer (EET). These proteins are potential targets to improve EET and enhance bioremediation and electrical current production by G. sulfurreducens. However, the functional characterization of multiheme cytochromes is particularly complex due to the co-existence of several microstates in solution, connecting the fully reduced and fully oxidized states. Over the last decade, new strategies have been developed to characterize multiheme redox proteins functionally and structurally. These strategies were used to reveal the functional mechanism of G. sulfurreducens multiheme cytochromes and also to identify key residues in these proteins for EET. In previous studies, we set the foundations for enhancement of the EET abilities of G. sulfurreducens by characterizing a family of five triheme cytochromes (PpcA-E). These periplasmic cytochromes are implicated in electron transfer between the oxidative reactions of metabolism in the cytoplasm and the reduction of extracellular terminal electron acceptors at the cell's outer surface. The results obtained suggested that PpcA can couple e(-)/H(+) transfer, a property that might contribute to the proton electrochemical gradient across the cytoplasmic membrane for metabolic energy production. The structural and functional properties of PpcA were characterized in detail and used for rational design of a family of 23 single site PpcA mutants. In this review, we summarize the functional characterization of the native and mutant proteins. Mutants that retain the mechanistic features of PpcA and adopt preferential e(-)/H(+) transfer pathways at lower reduction potential values compared to the wild-type protein were selected for in vivo studies as the best candidates to increase the electron transfer rate of G. sulfurreducens. For the first time G. sulfurreducens strains have been manipulated by the introduction of mutant forms of essential

  3. Measurement of the high energy component of the x-ray spectra in the VENUS electron cyclotron resonance ion source.

    PubMed

    Leitner, D; Benitez, J Y; Lyneis, C M; Todd, D S; Ropponen, T; Ropponen, J; Koivisto, H; Gammino, S

    2008-03-01

    High performance electron cyclotron resonance (ECR) ion sources, such as VENUS (Versatile ECR for NUclear Science), produce large amounts of x-rays. By studying their energy spectra, conclusions can be drawn about the electron heating process and the electron confinement. In addition, the bremsstrahlung from the plasma chamber is partly absorbed by the cold mass of the superconducting magnet, adding an extra heat load to the cryostat. Germanium or NaI detectors are generally used for x-ray measurements. Due to the high x-ray flux from the source, the experimental setup to measure bremsstrahlung spectra from ECR ion sources is somewhat different from that for the traditional nuclear physics measurements these detectors are generally used for. In particular, the collimation and background shielding can be problematic. In this paper, we will discuss the experimental setup for such a measurement, the energy calibration and background reduction, the shielding of the detector, and collimation of the x-ray flux. We will present x-ray energy spectra and cryostat heating rates depending on various ion source parameters, such as confinement fields, minimum B-field, rf power, and heating frequency. PMID:18377002

  4. Shewanella oneidensis MR-1 nanowires are outer membrane and periplasmic extensions of the extracellular electron transport components.

    PubMed

    Pirbadian, Sahand; Barchinger, Sarah E; Leung, Kar Man; Byun, Hye Suk; Jangir, Yamini; Bouhenni, Rachida A; Reed, Samantha B; Romine, Margaret F; Saffarini, Daad A; Shi, Liang; Gorby, Yuri A; Golbeck, John H; El-Naggar, Mohamed Y

    2014-09-01

    Bacterial nanowires offer an extracellular electron transport (EET) pathway for linking the respiratory chain of bacteria to external surfaces, including oxidized metals in the environment and engineered electrodes in renewable energy devices. Despite the global, environmental, and technological consequences of this biotic-abiotic interaction, the composition, physiological relevance, and electron transport mechanisms of bacterial nanowires remain unclear. We report, to our knowledge, the first in vivo observations of the formation and respiratory impact of nanowires in the model metal-reducing microbe Shewanella oneidensis MR-1. Live fluorescence measurements, immunolabeling, and quantitative gene expression analysis point to S. oneidensis MR-1 nanowires as extensions of the outer membrane and periplasm that include the multiheme cytochromes responsible for EET, rather than pilin-based structures as previously thought. These membrane extensions are associated with outer membrane vesicles, structures ubiquitous in Gram-negative bacteria, and are consistent with bacterial nanowires that mediate long-range EET by the previously proposed multistep redox hopping mechanism. Redox-functionalized membrane and vesicular extensions may represent a general microbial strategy for electron transport and energy distribution.

  5. Shewanella oneidensis MR-1 Nanowires are Outer Membrane and Periplasmic Extensions of the Extracellular Electron Transport Components

    SciTech Connect

    Pirbadian, S.; Barchinger, S. E.; Leung, K. M.; Byun, H. S.; Jangir, Y.; Bouhenni, Rachida; Reed, Samantha B.; Romine, Margaret F.; Saffarini, Daad; Shi, Liang; Gorby, Yuri A.; Golbeck, J. H.; El-Naggar, Mohamed Y.

    2014-08-20

    Bacterial nanowires offer an extracellular electron transport (EET) pathway for linking the respiratory chain of bacteria to external surfaces, including oxidized metals in the environment and engineered electrodes in renewable energy devices. Despite the global, environmental, and technological consequences of this biotic-abiotic interaction, the composition, physiological relevance, and electron transport mechanisms of bacterial nanowires remain unclear. We report the first in vivo observations of the formation and respiratory impact of nanowires in the model metal-reducing microbe Shewanella neidensis MR-1. Using live fluorescence measurements, immunolabeling, and quantitative gene expression analysis, we report that S. oneidensis MR-1 nanowires are extensions of the outer membrane and periplasm that include the multiheme cytochromes responsible for EET, rather than pilin-based structures, as previously thought. These bacterial nanowires were also associated with outer membrane vesicles and vesicle chains, structures ubiquitous in gram-negative bacteria. Redoxfunctionalized membrane and vesicular extensions may represent a general microbial strategy for electron transport and energy distribution.

  6. UPGRADE TO INITIAL BPM ELECTRONICS MODULE AND BEAMLINE COMPONENTS FOR CALIBRATION OF THE LEDA BEAM POSITION MEASUREMENTS

    SciTech Connect

    D.S. BARR; J.D. GILPATRICK; R.B. SHURTER

    2001-06-01

    The Low-Energy Demonstration Accelerator (LEDA), designed and built at the Los Alamos National Laboratory, is part of the Accelerator Production of Tritium (APT) program and provides a platform for measuring high-power proton beam-halo formation. Beam Position Monitors (BPMs) are placed along the FODO lattice and the HEBT. The BPM systems employing log-ratio processor electronics have recently been upgraded for all fifteen BPMs along the accelerator. Two types of calibration are now used. The first corrects for errors within the electronics module and the log-amp transfer function non-conformity. The second is a single-point routine used to correct for cable plant attenuation differences. This paper will also cover the new switching systems used for various system calibration modes as well as various results from LEDA beam runs. New switching algorithms were implemented in order to remove sensitive electronic switches from within the beam tunnel radiation environment. Attention will be paid to the calibration algorithms and switching system interactions, and how well they work in practice.

  7. Shewanella oneidensis MR-1 nanowires are outer membrane and periplasmic extensions of the extracellular electron transport components

    PubMed Central

    Pirbadian, Sahand; Barchinger, Sarah E.; Leung, Kar Man; Byun, Hye Suk; Jangir, Yamini; Bouhenni, Rachida A.; Reed, Samantha B.; Romine, Margaret F.; Saffarini, Daad A.; Shi, Liang; Gorby, Yuri A.; Golbeck, John H.; El-Naggar, Mohamed Y.

    2014-01-01

    Bacterial nanowires offer an extracellular electron transport (EET) pathway for linking the respiratory chain of bacteria to external surfaces, including oxidized metals in the environment and engineered electrodes in renewable energy devices. Despite the global, environmental, and technological consequences of this biotic–abiotic interaction, the composition, physiological relevance, and electron transport mechanisms of bacterial nanowires remain unclear. We report, to our knowledge, the first in vivo observations of the formation and respiratory impact of nanowires in the model metal-reducing microbe Shewanella oneidensis MR-1. Live fluorescence measurements, immunolabeling, and quantitative gene expression analysis point to S. oneidensis MR-1 nanowires as extensions of the outer membrane and periplasm that include the multiheme cytochromes responsible for EET, rather than pilin-based structures as previously thought. These membrane extensions are associated with outer membrane vesicles, structures ubiquitous in Gram-negative bacteria, and are consistent with bacterial nanowires that mediate long-range EET by the previously proposed multistep redox hopping mechanism. Redox-functionalized membrane and vesicular extensions may represent a general microbial strategy for electron transport and energy distribution. PMID:25143589

  8. Measurement of the high energy component of the x-ray spectra in the VENUS electron cyclotron resonance ion source

    SciTech Connect

    Leitner, D.; Benitez, J. Y.; Lyneis, C. M.; Todd, D. S.; Ropponen, T.; Ropponen, J.; Koivisto, H.; Gammino, S.

    2008-03-15

    High performance electron cyclotron resonance (ECR) ion sources, such as VENUS (Versatile ECR for NUclear Science), produce large amounts of x-rays. By studying their energy spectra, conclusions can be drawn about the electron heating process and the electron confinement. In addition, the bremsstrahlung from the plasma chamber is partly absorbed by the cold mass of the superconducting magnet, adding an extra heat load to the cryostat. Germanium or NaI detectors are generally used for x-ray measurements. Due to the high x-ray flux from the source, the experimental setup to measure bremsstrahlung spectra from ECR ion sources is somewhat different from that for the traditional nuclear physics measurements these detectors are generally used for. In particular, the collimation and background shielding can be problematic. In this paper, we will discuss the experimental setup for such a measurement, the energy calibration and background reduction, the shielding of the detector, and collimation of the x-ray flux. We will present x-ray energy spectra and cryostat heating rates depending on various ion source parameters, such as confinement fields, minimum B-field, rf power, and heating frequency.

  9. Carboxymethyl cellulose/silica hybrids as templates for calcium phosphate biomimetic mineralization.

    PubMed

    Salama, Ahmed; Abou-Zeid, Ragab E; El-Sakhawy, Mohamed; El-Gendy, Ahmed

    2015-03-01

    Multiphase hybrid materials were synthesized using carboxymethyl cellulose (CMC) as bioactive polymer, silica gel as matrix assisted networks and calcium phosphate as inorganic mineral phase. These hybrids were investigated with infrared spectroscopy, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy and transmission electron microscopy. Biomimetic crystal growth nucleated from the CMC/silica hybrids was suggested as amorphous calcium phosphate with an evidence that hydroxyapatite, the mineralized component of bone, may be formed at high CMC content. This study provides an efficient approach toward bone-like hybrids with potential bone healing applications. PMID:25526694

  10. Industrial Minerals

    ERIC Educational Resources Information Center

    Bradbury, James C.

    1978-01-01

    The past year is seen as not particularly good for industrial minerals and for industry in general. Environmental concerns continued to trouble the industry with unacceptable asbestos concentrations and chlorofluorocarbon effects on ozone. A halting U.S. economy also affected industrial progress. (MA)

  11. [Photosynthetic activity and components of the electron transport chain in the aerobic bacteriochlorophyll A-containing bacterium Roseinatronobacter thiooxidans].

    PubMed

    Stadnichuk, I N; Ianiushin, M F; Boĭchenko, V A; Lukashev, E P; Boldareva, E N; Solov'ev, A A; Gorlenko, V M

    2009-01-01

    Bioenergetics of the aerobic bacteriochlorophyll a-containing (BCl a) bacterium (ABC bacterium) Roseinatronobacter thiooxidans is a combination of photosynthesis, oxygen respiration, and oxidation of sulfur compounds under alkaliphilic conditions. The photosynthetic activity of Rna. thiooxidans cells was established by the photoinhibition of cell respiration and reversible photobleaching discoloration of the BCl a of reaction centers (RC), connected by the chain of electron transfer with cytochrome c551 oxidation. The species under study, like many purple bacteria and some of the known ABC bacteria, possesses a light-harvesting pigment-protein (LHI) complex with the average number of 30 molecules of antenna BCl a per one photosynthetic RC. Under microaerobic growth conditions, the cells contained bc1 complex and two terminal oxidases: cbb3-cytochrome oxidase and the alternative cytochrome oxidase of the a3 type. Besides, Rna. thiooxidans was shown to have several different soluble low- and high-potential cytochromes c, probably associated with the ability of utilizing sulfur compounds as additional electron donors.

  12. Electron density characteristics in bond critical point (QTAIM) versus interaction energy components (SAPT): the case of charge-assisted hydrogen bonding.

    PubMed

    Bankiewicz, Barbara; Matczak, Piotr; Palusiak, Marcin

    2012-01-12

    Charge-assisted hydrogen bonds (CAHBs) of N-H···Cl, N-H···Br, and P-H···Cl type were investigated using advanced computational approach (MP2/aug-cc-pVTZ level of theory). The properties of electron density function defined in the framework of Quantum Theory of Atoms in Molecules (QTAIM) were estimated as a function of distance in H-bridges. Additionally, the interaction energy decomposition was performed for H-bonded complexes with different H-bond lengths using the Symmetry-Adapted Perturbation Theory (SAPT). In this way both QTAIM parameters and SAPT energy components could be expressed as a function of the same variable, that is, the distance in H-bridge. A detailed analysis of the changes in QTAIM and SAPT parameters due to the changes in H···A distance revealed that, over some ranges of H···A distances, electrostatic, inductive and dispersive components of the SAPT interaction energy show a linear correlation with the value of the electron density at H-BCP ρ(BCP). The linear relation between the induction component, E(ind), and ρ(BCP) confirms numerically the intuitive expectation that the ρ(BCP) reflects directly the effects connected with the sharing of electron density between interacting centers. These conclusions are important in view of charge density studies performed for crystals in which the distance between atoms results not only from effects connected with the interaction between atomic centers directly involved in bonding, but also from packing effects which may strongly influence the length of the H-bond.

  13. Policy design in closed-loop supply chains for the integrated management of component recycling and spare parts supply in the electronics industry

    NASA Astrophysics Data System (ADS)

    Schroeter, Marcus; Spengler, Thomas

    2004-02-01

    The strategy to recover components from discarded electrical and electronic equipment to obtain spare parts is promising, especially during the final service phase. In that phase, the original product is no longer produced and the sources of new parts are often limited. Controlling those closed-loop supply chains is challenging. Decision makers have to choose when to acquire discarded equipment, when to recover used parts, and when to produce new parts. We developed a generic system dynamics model that provides a test for various proposed policies to control closed-loop supply chains with parts recovery and spare-parts supply.

  14. A Discussion on Uncertainty Representation and Interpretation in Model-Based Prognostics Algorithms based on Kalman Filter Estimation Applied to Prognostics of Electronics Components

    NASA Technical Reports Server (NTRS)

    Celaya, Jose R.; Saxen, Abhinav; Goebel, Kai

    2012-01-01

    This article discusses several aspects of uncertainty representation and management for model-based prognostics methodologies based on our experience with Kalman Filters when applied to prognostics for electronics components. In particular, it explores the implications of modeling remaining useful life prediction as a stochastic process and how it relates to uncertainty representation, management, and the role of prognostics in decision-making. A distinction between the interpretations of estimated remaining useful life probability density function and the true remaining useful life probability density function is explained and a cautionary argument is provided against mixing interpretations for the two while considering prognostics in making critical decisions.

  15. Controlling Electron Transfer between the Two Cofactor Chains of Photosystem I by the Redox State of One of Their Components

    PubMed Central

    Santabarbara, Stefano; Bullock, Bradford; Rappaport, Fabrice; Redding, Kevin E.

    2015-01-01

    Two functional electron transfer (ET) chains, related by a pseudo-C2 symmetry, are present in the reaction center of photosystem I (PSI). Due to slight differences in the environment around the cofactors of the two branches, there are differences in both the kinetics of ET and the proportion of ET that occurs on the two branches. The strongest evidence that this is indeed the case relied on the observation that the oxidation rates of the reduced phylloquinone (PhQ) cofactor differ by an order of magnitude. Site-directed mutagenesis of residues involved in the respective PhQ-binding sites resulted in a specific alteration of the rates of semiquinone oxidation. Here, we show that the PsaA-F689N mutation results in an ∼100-fold decrease in the observed rate of PhQA− oxidation. This is the largest change of PhQA− oxidation kinetics observed so far for a single-point mutation, resulting in a lifetime that exceeds that of the terminal electron donor, P700+. This situation allows a second photochemical charge separation event to be initiated before PhQA− has decayed, thereby mimicking in PSI a situation that occurs in type II reaction centers. The results indicate that the presence of PhQA− does not impact the overall quantum yield and leads to an almost complete redistribution of the fractional utilization of the two functional ET chains, in favor of the one that does not bear the charged species. The evolutionary implications of these results are also briefly discussed. PMID:25809266

  16. Structural determination of carvone, a component of spearmint, by means of gas electron diffraction augmented by theoretical calculations

    NASA Astrophysics Data System (ADS)

    Egawa, Toru; Kachi, Yukari; Takeshima, Tsuguhide; Takeuchi, Hiroshi; Konaka, Shigehiro

    2003-10-01

    The molecular structure and conformation of carvone, a compound with a minty odor, were investigated by means of gas electron diffraction supported by theoretical calculations. Electron diffraction patterns were recorded by heating the nozzle up to 128 °C to obtain enough scattering intensity. The infrared spectrum was also measured by using an absorption cell with a path length of 10 m. The obtained molecular scattering intensities were analyzed with the aid of theoretical calculations and infrared spectroscopy. It was revealed that the experimental data are well reproduced by assuming that carvone consists of a mixture of three conformers that have the isopropenyl group in the equatorial position and mutually differ in the torsional angle around the single bond connecting the ring and the isopropenyl group. It was also found that the puckering amplitude of the ring of carvone is close to those of menthol and isomenthol, a minty compound and its nonminty isomer. The determined structural parameters ( rg and ∠ α) of the most abundant conformer of carvone are as follows: < r(C-C)>=1.520(3) Å; < r(CC)>=1.360(5) Å; r(CO)=1.225(5) Å; < r(C-H)>=1.104(4)Å; <∠CC-C>=121.1(5)°; <∠C-C-C>=110.4(5)°; ∠C-CO-C=117.1(14)°; <∠C-C-H>=111.1(13)°. Angle brackets denote average values and parenthesized values are the estimated limits of error (3 σ) referring to the last significant digit.

  17. Mineral bioprocessing

    SciTech Connect

    Torma, A.E.

    1993-05-01

    In the last 25 years, the introduction of biotechnological methods in hydrometallurgy has created new opportunities and challenges for the mineral processing industry. This was especially true for the production of metal values from mining wastes and low-and-complex-grade mineral resources, which were considered economically not amenable for processing by conventional extraction methods. Using bio-assisted heap, dump and in-situ leaching technologies, copper and uranium extractions gained their first industrial applications. The precious metal industries were the next to adopt the bio-preoxidation technique in the extraction of gold from refractory sulfide-bearing ores and concentrates. A variety of other bioleaching opportunities exist for nickel, cobalt, cadmium and zinc sulfide leaching. Recently developed bioremediation methods and biosorption technologies have shown a good potential for industrial applications to remove trace heavy metal and radionuclide concentrations from contaminated soils, and mining and processing effluents.

  18. Oxidation reactions of cytosine DNA components by hydroxyl radical and one-electron oxidants in aerated aqueous solutions.

    PubMed

    Wagner, J Richard; Cadet, Jean

    2010-04-20

    Indirect evidence strongly suggests that oxidation reactions of cytosine and its minor derivative 5-methylcytosine play a major role in mutagenesis and cancer. Therefore, there is an emerging necessity to identify the final oxidation products of these reactions, to search for their formation in cellular DNA, and to assess their mutagenic features. In this Account, we report and discuss the main *OH and one-electron-mediated oxidation reactions, two of the most potent sources of DNA damage, of cytosine and 5-methylcytosine nucleosides that have been recently characterized. The addition of *OH to the 5,6-unsaturated double bond of cytosine and 5-methylcytosine generates final degradation products that resemble those observed for uracil and thymine. The main product from the oxidation of cytosine, cytosine glycol, has been shown to undergo dehydration at a much faster rate as a free nucleoside than when inserted into double-stranded DNA. On the other hand, the predominant *OH addition at C5 of cytosine or 5-methylcytosine leads to the formation of 5-hydroxy-5,6-dihydro radicals that give rise to novel products with an imidazolidine structure. The mechanism of the formation of imidazolidine products is accounted for by rearrangement reactions that in the presence of molecular oxygen likely involve an intermediate pyrimidine endoperoxide. The reactions of the radical cations of cytosine and 5-methylcytosine are governed by competitive hydration, mainly at C6 of the pyrimidine ring, and deprotonation from the exocyclic amino and methyl group, leading in most cases to products similar to those generated by *OH. 5-Hydroxypyrimidines, the dehydration products of cytosine and uracil glycols, have a low oxidation potential, and their one-electron oxidation results in a cascade of decomposition reactions involving the formation of isodialuric acid, dialuric acid, 5-hydroxyhydantoin, and its hydroxyketone isomer. In biology, GC --> AT transitions are the most common mutations

  19. Relationship between nanoscale mineral properties and calcein labeling in mineralizing bone surfaces.

    PubMed

    Aido, Marta; Kerschnitzki, Michael; Hoerth, Rebecca; Burghammer, Manfred; Montero, Cédric; Checa, Sara; Fratzl, Peter; Duda, Georg N; Willie, Bettina M; Wagermaier, Wolfgang

    2014-08-01

    Bone's mineral properties, such as particle thickness and degree of alignment have been associated with bone quality. Bone formation, remodeling, aging of the tissue and mineral homeostasis influence mineral particle properties leading to specific patterns across bone. Scanning small angle X-ray scattering (sSAXS) with synchrotron radiation is a powerful tool, which allows us to study bone's nanoscale mineral properties in a position-resolved way. We used sSAXS, fluorescence light microscopy and backscattered electron (BSE) imaging to study bone's mineral properties at the tibial midshaft of in vivo-loaded mice. By combining these techniques, we could detect local changes in mineral properties. Regions labeled with calcein fluorochrome have lower mean mineral thickness and degree of mineral alignment. We also observed thinner and less aligned mineral particles near blood vessels. We conclude that mineral properties (i) are altered by fluorochrome labeling and (ii) depend on the proximity to blood vessels.

  20. Green Clay Minerals

    NASA Astrophysics Data System (ADS)

    Velde, B.

    2003-12-01

    part of it is reduced, another is formed. This is the fundamental geochemical aspect of the genesis of green clay minerals; they contain iron in both oxidation states.Unfortunately modern methods of mineral analysis on a microscopic scale, electron microbeam and others, do not allow the determination of the different oxidation states of iron especially for nonstoichiometric minerals. One can use Mössbauer spectral analysis, but the scales of observations are not the same (Mössbauer needing more material); one method used for observations on a microscale, the other on a macroscale. Given the problems of micro- and macroscale observations, oxidation state information is almost excluded from data gathered since the 1980s or so, and hence information concerning the relations of iron reduction and clay genesis must be taken from older studies. A second, much greater problem is that little X-ray diffraction (XRD) work is done on samples which are analyzed chemically by electron microbeam studies. In the past both types of information, structural and chemical, were available for the same sample. Hence not only do we have no precise chemical data for many samples (oxidation state of iron), but there is a rarity of mineral structural information to go along with the incomplete chemistry. This is critical for the study of clay minerals, because slight chemical changes in a clay mineral are frequently accompanied by changes in its structure, especially when one deals with interstratified clay minerals (mica/smectites for example). In fact, the tendency to obtain more and more precision (analysis of a smaller and smaller sized sample) has led to a total loss of mineralogical data. The Heisenberg principle is unwittingly verified by geologists. We know more about a small part of a sample, but we know less about its whole. As a result, the following discussion is based largely upon old data, those which combine iron oxidation states and XRD information.

  1. BET Measurements: Outgassing of Minerals.

    PubMed

    Clausen; Fabricius

    2000-07-01

    Outgassing minerals at elevated temperatures prior to BET measurements can lead to phase changes, especially in the case of amorphous and poorly crystalline materials. In order to evaluate the applicability of the BET method when low outgassing temperatures are required, selected aquifer minerals were outgassed at different temperatures and for different times. The studied minerals are 2-line ferrihydrite, goethite, lepidocrocite, quartz, calcite, alpha-alumina, and kaolinite. The results demonstrate that measured specific surface areas of iron oxides are strongly dependent on outgassing conditions because the surface area increased by 170% with increasing temperature. In the poorly crystalline minerals, phase changes caused by heating were observed at temperatures lower than 100 degrees C. Therefore low outgassing temperatures are preferable for minimizing phase changes. As demonstrated in this study, stable BET values can be obtained by increasing the outgassing time without heating iron oxides. For quartz, calcite, alpha-alumina, and kaolinite, stable BET values were obtained after outgassing the minerals at 100 to 250 degrees C for 2 h. However, outgassing these minerals at room temperature (20 degrees C) only resulted in minor errors, implying that aquifer sediments containing poorly crystalline materials can be outgassed at low temperatures if the outgassing time is increased. Scanning electron microscopy of the studied minerals demonstrated that the particle size as calculated from BET data compares well with particle size observed by scanning electron microscopy images. Copyright 2000 Academic Press.

  2. Two-component relativistic density-functional calculations of the dimers of the halogens from bromine through element 117 using effective core potential and all-electron methods.

    PubMed

    Mitin, Alexander V; van Wüllen, Christoph

    2006-02-14

    A two-component quasirelativistic Hamiltonian based on spin-dependent effective core potentials is used to calculate ionization energies and electron affinities of the heavy halogen atom bromine through the superheavy element 117 (eka-astatine) as well as spectroscopic constants of the homonuclear dimers of these atoms. We describe a two-component Hartree-Fock and density-functional program that treats spin-orbit coupling self-consistently within the orbital optimization procedure. A comparison with results from high-order Douglas-Kroll calculations--for the superheavy systems also with zeroth-order regular approximation and four-component Dirac results--demonstrates the validity of the pseudopotential approximation. The density-functional (but not the Hartree-Fock) results show very satisfactory agreement with theoretical coupled cluster as well as experimental data where available, such that the theoretical results can serve as an estimate for the hitherto unknown properties of astatine, element 117, and their dimers. PMID:16483205

  3. Changes to the Disordered Phase and Apatite Crystallite Morphology during Mineralization by an Acidic Mineral Binding Peptide from Osteonectin.

    PubMed

    Iline-Vul, Taly; Matlahov, Irina; Grinblat, Judith; Keinan-Adamsky, Keren; Goobes, Gil

    2015-09-14

    Noncollagenous proteins regulate the formation of the mineral constituent in hard tissue. The mineral formed contains apatite crystals coated by a functional disordered calcium phosphate phase. Although the crystalline phase of bone mineral was extensively investigated, little is known about the disordered layer's composition and structure, and less is known regarding the function of noncollagenous proteins in the context of this layer. In the current study, apatite was prepared with an acidic peptide (ON29) derived from the bone/dentin protein osteonectin. The mineral formed comprises needle-shaped hydroxyapatite crystals like in dentin and a stable disordered phase coating the apatitic crystals as shown using X-ray diffraction, transmission electron microscopy, and solid-state NMR techniques. The peptide, embedded between the mineral particles, reduces the overall phosphate content in the mineral formed as inferred from inductively coupled plasma and elemental analysis results. Magnetization transfers between disordered phase species and apatitic phase species are observed for the first time using 2D (1)H-(31)P heteronuclear correlation NMR measurements. The dynamics of phosphate magnetization transfers reveal that ON29 decreases significantly the amount of water molecules in the disordered phase and increases slightly their content at the ordered-disordered interface. The peptide decreases hydroxyl to disordered phosphate transfers within the surface layer but does not influence transfer within the bulk crystalline mineral. Overall, these results indicate that control of crystallite morphology and properties of the inorganic component in hard tissue by biomolecules is more involved than just direct interaction between protein functional groups and mineral crystal faces. Subtler mechanisms such as modulation of the disordered phase composition and structural changes at the ordered-disordered interface may be involved. PMID:26207448

  4. Micro and nano-size pores of clay minerals in shale reservoirs: Implication for the accumulation of shale gas

    NASA Astrophysics Data System (ADS)

    Chen, Shangbin; Han, Yufu; Fu, Changqin; Zhang, han; Zhu, Yanming; Zuo, Zhaoxi

    2016-08-01

    A pore is an essential component of shale gas reservoirs. Clay minerals are the adsorption carrier second only to organic matter. This paper uses the organic maturity test, Field-Emission Scanning Electron Microscopy (FE-SEM), and X-ray Diffraction (XRD) to study the structure and effect of clay minerals on storing gas in shales. Results show the depositional environment and organic maturity influence the content and types of clay minerals as well as their structure in the three types of sedimentary facies in China. Clay minerals develop multi-size pores which shrink to micro- and nano-size by close compaction during diagenesis. Micro- and nano-pores can be divided into six types: 1) interlayer, 2) intergranular, 3) pore and fracture in contact with organic matter, 4) pore and fracture in contact with other types of minerals, 5) dissolved and, 6) micro-cracks. The contribution of clay minerals to the presence of pores in shale is evident and the clay plane porosity can even reach 16%, close to the contribution of organic matter. The amount of clay minerals and pores displays a positive correlation. Clay minerals possess a strong adsorption which is affected by moisture and reservoir maturity. Different pore levels of clay minerals are mutually arranged, thus essentially producing distinct reservoir adsorption effects. Understanding the structural characteristics of micro- and nano-pores in clay minerals can provide a tool for the exploration and development of shale gas reservoirs.

  5. Vitamins and Minerals

    MedlinePlus

    ... I Help a Friend Who Cuts? Vitamins and Minerals KidsHealth > For Teens > Vitamins and Minerals Print A ... of a good thing? What Are Vitamins and Minerals? Vitamins and minerals make people's bodies work properly. ...

  6. [Mineral water as a cure].

    PubMed

    Nocco, Priska Binz

    2008-01-01

    The treatment of diseases with mineral spring water belongs to the oldest medical therapies. The "remedy" mineral water is therefore of importance also within the pharmacy. The present pharmacy historical work examines the impact of the use of mineral waters, as well as of their dried components, as therapeutic agents in the 19th and early 20th centuries, i.e. from approx. 1810 to 1930, as well as the contributions given by pharmacists in the development and analysis of mineral water springs. Beside these aspects, the aim here is also to describe the role played by pharmacists in the production of artificial mineral water as well as in the sale and wholesale of natural and artificial mineral water. In the first part of this work the situation in Switzerland and its surrounding countries, such as Germany, France, Italy and Austria, is discussed. The second part contains a case-study of the particular situation in the Canton Tessin. It is known from the scientific literature published at that time that information on mineral water was frequently reported. Starting from the beginning of the 19th century the number of such publications increased tremendously. The major part of them were publications in scientific journals or contributions to medical and pharmaceutical manuals and reference books. In particular the spa-related literature, such as spa-guides, was of growing interest to a broad public. The inclusion of monographs into the Swiss, the Cantonal as well the foreign pharmacopoeias granted a legal frame for the mineral waters and their dried components. These works are of major importance from a pharmacy historical standpoint and represent a unique proof of historical evidence of the old medicinal drug heritage. The most frequently used therapies based on mineral waters were drinking and bath cures. Several diseases, particularly those of a chronic character, were treated with mineral waters. The positive influence of these cures on the recovery of the patients

  7. Microstructural architecture developed in the fabrication of solid and open-cellular copper components by additive manufacturing using electron beam melting

    NASA Astrophysics Data System (ADS)

    Ramirez, Diana Alejandra

    The fabrication of Cu components were first built by additive manufacturing using electron beam melting (EBM) from low-purity, atomized Cu powder containing a high density of Cu2O precipitates leading to a novel example of precipitate-dislocation architecture. These microstructures exhibit cell-like arrays (1-3microm) in the horizontal reference plane perpendicular to the build direction with columnar-like arrays extending from ~12 to >60 microm in length and corresponding spatial dimensions of 1-3 microm. These observations were observed by the use of optical metallography, and scanning and transmission electron microscopy. The hardness measurements were taken both on the atomized powder and the Cu components. The hardness for these architectures ranged from ~HV 83 to 88, in contrast to the original Cu powder microindentation hardness of HV 72 and the commercial Cu base plate hardness of HV 57. These observations were utilized for the fabrication of open-cellular copper structures by additive manufacturing using EBM and illustrated the ability to fabricate some form of controlled microstructural architecture by EBM parameter alteration or optimizing. The fabrication of these structures ranged in densities from 0.73g/cm3 to 6.67g/cm3. These structures correspond to four different articulated mesh arrays. While these components contained some porosity as a consequence of some unmelted regions, the Cu2O precipitates also contributed to a reduced density. Using X-ray Diffraction showed the approximate volume fraction estimated to be ~2%. The addition of precipitates created in the EBM melt scan formed microstructural arrays which contributed to hardening contributing to the strength of mesh struts and foam ligaments. The measurements of relative stiffness versus relative density plots for Cu compared very closely with Ti-6Al-4V open cellular structures - both mesh and foams. The Cu reticulated mesh structures exhibit a slope of n = 2 in contrast to a slope of n = 2

  8. Manganese oxide minerals: Crystal structures and economic and environmental significance

    PubMed Central

    Post, Jeffrey E.

    1999-01-01

    Manganese oxide minerals have been used for thousands of years—by the ancients for pigments and to clarify glass, and today as ores of Mn metal, catalysts, and battery material. More than 30 Mn oxide minerals occur in a wide variety of geological settings. They are major components of Mn nodules that pave huge areas of the ocean floor and bottoms of many fresh-water lakes. Mn oxide minerals are ubiquitous in soils and sediments and participate in a variety of chemical reactions that affect groundwater and bulk soil composition. Their typical occurrence as fine-grained mixtures makes it difficult to study their atomic structures and crystal chemistries. In recent years, however, investigations using transmission electron microscopy and powder x-ray and neutron diffraction methods have provided important new insights into the structures and properties of these materials. The crystal structures for todorokite and birnessite, two of the more common Mn oxide minerals in terrestrial deposits and ocean nodules, were determined by using powder x-ray diffraction data and the Rietveld refinement method. Because of the large tunnels in todorokite and related structures there is considerable interest in the use of these materials and synthetic analogues as catalysts and cation exchange agents. Birnessite-group minerals have layer structures and readily undergo oxidation reduction and cation-exchange reactions and play a major role in controlling groundwater chemistry. PMID:10097056

  9. 4-Component correlated all-electron study on Eka-actinium Fluoride (E121F) including Gaunt interaction: Accurate analytical form, bonding and influence on rovibrational spectra

    NASA Astrophysics Data System (ADS)

    Amador, Davi H. T.; de Oliveira, Heibbe C. B.; Sambrano, Julio R.; Gargano, Ricardo; de Macedo, Luiz Guilherme M.

    2016-10-01

    A prolapse-free basis set for Eka-Actinium (E121, Z = 121), numerical atomic calculations on E121, spectroscopic constants and accurate analytical form for the potential energy curve of diatomic E121F obtained at 4-component all-electron CCSD(T) level including Gaunt interaction are presented. The results show a strong and polarized bond (≈181 kcal/mol in strength) between E121 and F, the outermost frontier molecular orbitals from E121F should be fairly similar to the ones from AcF and there is no evidence of break of periodic trends. Moreover, the Gaunt interaction, although small, is expected to influence considerably the overall rovibrational spectra.

  10. Structure and chemical characteristics of natural mineral deposit Terbunskaya (Lipetsk region, Russia)

    SciTech Connect

    Motyleva, S. Mertvishcheva, M.; Shchuchka, R.; Gulidova, V.

    2015-07-22

    New knowledge about the mineralogical features Terbunsky mineral. Investigated 5 fractions isolated from the incision (2-2,5 m). Terbunskaya deposit belongs to minerals Santonian age. Scanning electron microscopy and energy dispersive analysis of fractions isolated studied in detail. In the coarse fractions found ancient organic remains of algae and micro-organisms that have been sedimented together with the mineral component during geological periods. The share of organic inclusions does not exceed 1.5%. Chemical composition confirms the presence of silicon and carbonate organisms. Advantageously proportion of minerals having a layered structure with a plurality of micro and nano pore size 600 - 80-nm and an average chemical composition (wt%): Na (0,64), Mg (0,54), Al (13.48), Si (27 57), K (2.39) Ca (0.75)

  11. An electron microscopy study of the microstructure and microarchitecture of the Strombus gigas shell

    SciTech Connect

    Rieke, P.C.; Laraia, V.J. ); Heuer, A.H. ); Aindow, M. )

    1989-11-01

    A scanning and transmission electron microscopy study is presented of the microstructure of the Strombus gigas shell. The hierarchical nature of this crossed-lamellar structure and the defect content of the mineral component are described. The mineral component consists of small single crystal grains of aragonite, the metastable orthorhombic polymorph of CaCO{sub 3}. The habit and morphology of the grains discussed here have not been determined previously. The observed habit and defect structure suggest that the organic matrix exerts a high degree of control over the crystal growth of the mineral phase and is responsible for the long range order in the microarhitecture. Electron beam heating of the mineral component leads to certain phase changes and these are discussed. 15 refs., 6 figs.

  12. [Determination of carcinogenic aromatic amines derived from azo colorants in plastic components of electrical and electronic products by high performance liquid chromatography-mass spectrometry].

    PubMed

    Niu, Zengyuan; Luo, Xin; Ye, Xiwen; Wang, Huihui; Li, Jingying

    2014-01-01

    A study for the simultaneous determination of 21 primary aromatic amines derived from the reduction of the azo colorants in plastic components of electrical and electronic products was conducted. Organic solvents were used to dissolve or swell the plastics to release the azo dyes existing in the plastic components. The azo colorants were reduced to aromatic amines under strong reducing condition of dithionite. Aromatic amines were extracted with methyl tert-butyl ether. Methanol-water (1: 1, v/v) was used to concentrate the extract to constant-volume for HPLC-MS analysis. The analytes were separated on a ZORBAX Eclipse XDB C18 column using the gradient elution with acetonitrile and 0.1% (v/v) formic acid aqueous solution at a flow rate of 0.6 mL/min. The analyte confirmation was performed using retention time and characteristic ions in selected ion monitoring (SIM) mode. The correlation coefficients (r) of all the standard curves were more than 0.998, and the limits of quantification of the analytes were 0.5 mg/kg. The recoveries were 60.1% - 129.5% for the 21 aromatic amines with the RSDs not more than 14.0% except for a few compounds. The results showed that the banned azo colorants in the plastic products can be analyzed qualitatively and quantitatively through reductive conversion into aromatic amines. In addition, this method has high accuracy and good precision.

  13. Solution of the Dirac equation using the Rayleigh-Ritz method: Flexible basis coupling large and small components. Results for one-electron systems.

    PubMed

    Bağcı, A; Hoggan, P E

    2016-07-01

    An algebraic solution of the Dirac equation is reinvestigated. Slater-type spinor orbitals and their corresponding system of differential equations are defined in two- and four-component formalism. They describe the radial function in components of the wave function of the Dirac equation solution to high accuracy. They constitute the matrix elements arising in a generalized eigenvalue equation. These terms are evaluated through prolate spheroidal coordinates. The corresponding integrals are calculated by the numerical global-adaptive method taking into account the Gauss-Kronrod numerical integration extension. Sample calculations are performed using flexible basis sets generated with both signs of the relativistic angular momentum quantum number κ. Applications to one-electron atoms and diatomics are detailed. Variationally optimum values for orbital parameters are obtained at given nuclear separation. Methods discussed in this work are capable of yielding highly accurate relativistic two-center integrals for all ranges of orbital parameters. This work provides an efficient way to overcome the problems that arise in relativistic calculations. PMID:27575231

  14. Solution of the Dirac equation using the Rayleigh-Ritz method: Flexible basis coupling large and small components. Results for one-electron systems

    NASA Astrophysics Data System (ADS)

    Baǧcı, A.; Hoggan, P. E.

    2016-07-01

    An algebraic solution of the Dirac equation is reinvestigated. Slater-type spinor orbitals and their corresponding system of differential equations are defined in two- and four-component formalism. They describe the radial function in components of the wave function of the Dirac equation solution to high accuracy. They constitute the matrix elements arising in a generalized eigenvalue equation. These terms are evaluated through prolate spheroidal coordinates. The corresponding integrals are calculated by the numerical global-adaptive method taking into account the Gauss-Kronrod numerical integration extension. Sample calculations are performed using flexible basis sets generated with both signs of the relativistic angular momentum quantum number κ . Applications to one-electron atoms and diatomics are detailed. Variationally optimum values for orbital parameters are obtained at given nuclear separation. Methods discussed in this work are capable of yielding highly accurate relativistic two-center integrals for all ranges of orbital parameters. This work provides an efficient way to overcome the problems that arise in relativistic calculations.

  15. Molecular Characterization of Bacterial Respiration on Minerals

    SciTech Connect

    Blake, Robert C.

    2013-04-26

    The overall aim of this project was to contribute to our fundamental understanding of proteins and biological processes under extreme environmental conditions. We sought to define the biochemical and physiological mechanisms that underlie biodegradative and other cellular processes in normal, extreme, and engineered environments. Toward that end, we sought to understand the substrate oxidation pathways, the electron transport mechanisms, and the modes of energy conservation employed during respiration by bacteria on soluble iron and insoluble sulfide minerals. In accordance with these general aims, the specific aims were two-fold: To identify, separate, and characterize the extracellular biomolecules necessary for aerobic respiration on iron under strongly acidic conditions; and to elucidate the molecular principles whereby these bacteria recognize and adhere to their insoluble mineral substrates under harsh environmental conditions. The results of these studies were described in a total of nineteen manuscripts. Highlights include the following: 1. The complete genome of Acidithiobacillus ferrooxidans ATCC 23270 (type strain) was sequenced in collaboration with the DOE Joint Genome Institute; 2. Genomic and mass spectrometry-based proteomic methods were used to evaluate gene expression and in situ microbial activity in a low-complexity natural acid mine drainage microbial biofilm community. This was the first effort to successfully analyze a natural community using these techniques; 3. Detailed functional and structural studies were conducted on rusticyanin, an acid-stable electron transfer protein purified from cell-free extracts of At. ferrooxidans. The three-dimensional structure of reduced rusticyanin was determined from a combination of homonuclear proton and heteronuclear 15N- and 13C-edited NMR spectra. Concomitantly, the three-dimensional structure of oxidized rusticyanin was determined by X-ray crystallography to a resolution of 1.9 A by multiwavelength

  16. Mineralization of Carbon Dioxide: Literature Review

    SciTech Connect

    Romanov, V; Soong, Y; Carney, C; Rush, G; Nielsen, B; O'Connor, W

    2015-01-01

    CCS research has been focused on CO2 storage in geologic formations, with many potential risks. An alternative to conventional geologic storage is carbon mineralization, where CO2 is reacted with metal cations to form carbonate minerals. Mineralization methods can be broadly divided into two categories: in situ and ex situ. In situ mineralization, or mineral trapping, is a component of underground geologic sequestration, in which a portion of the injected CO2 reacts with alkaline rock present in the target formation to form solid carbonate species. In ex situ mineralization, the carbonation reaction occurs above ground, within a separate reactor or industrial process. This literature review is meant to provide an update on the current status of research on CO2 mineralization. 2

  17. Glycine Polymerization on Oxide Minerals

    NASA Astrophysics Data System (ADS)

    Kitadai, Norio; Oonishi, Hiroyuki; Umemoto, Koichiro; Usui, Tomohiro; Fukushi, Keisuke; Nakashima, Satoru

    2016-07-01

    It has long been suggested that mineral surfaces played an important role in peptide bond formation on the primitive Earth. However, it remains unclear which mineral species was key to the prebiotic processes. This is because great discrepancies exist among the reported catalytic efficiencies of minerals for amino acid polymerizations, owing to mutually different experimental conditions. This study examined polymerization of glycine (Gly) on nine oxide minerals (amorphous silica, quartz, α-alumina and γ-alumina, anatase, rutile, hematite, magnetite, and forsterite) using identical preparation, heating, and analytical procedures. Results showed that a rutile surface is the most effective site for Gly polymerization in terms of both amounts and lengths of Gly polymers synthesized. The catalytic efficiency decreased as rutile > anatase > γ-alumina > forsterite > α- alumina > magnetite > hematite > quartz > amorphous silica. Based on reported molecular-level information for adsorption of Gly on these minerals, polymerization activation was inferred to have arisen from deprotonation of the NH3 + group of adsorbed Gly to the nucleophilic NH2 group, and from withdrawal of electron density from the carboxyl carbon to the surface metal ions. The orientation of adsorbed Gly on minerals is also a factor influencing the Gly reactivity. The examination of Gly-mineral interactions under identical experimental conditions has enabled the direct comparison of various minerals' catalytic efficiencies and has made discussion of polymerization mechanisms and their relative influences possible Further systematic investigations using the approach reported herein (which are expected to be fruitful) combined with future microscopic surface analyses will elucidate the role of minerals in the process of abiotic peptide bond formation.

  18. Characterization of mineral particles in winter fog of Beijing analyzed by TEM and SEM.

    PubMed

    Li, Weijun; Shao, Longyi

    2010-02-01

    Aerosol samples were collected during winter fog and nonfog episodes in Beijing. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were applied to study morphologies, sizes, and compositions of aerosol particles. TEM observation indicates that most mineral particles collected in fog episode are scavenged in fog droplets. Number-size distributions of mineral particles collected in fog and nonfog episodes show two main peaks at the ranges of 0.1-0.3 and 1-2.5 microm, respectively. Based on their major compositions, mineral particles mainly include Si-rich, Ca-rich, and S-rich. Average S/Ca ratio of mineral particles collected in fog episode is 6.11, being eight times higher than that in nonfog episodes. Development mechanism of individual mineral particles in fog droplets is proposed. It is suggested that mineral particles with abundant alkaline components (e.g., "Ca-rich" particles) occurred in air should alleviate acidic degree of fog and contribute to complexity of fog droplets in Beijing.

  19. Earth mineral resource of the month: asbestos

    USGS Publications Warehouse

    Virta, Robert L.

    2010-01-01

    The article discusses the characteristics and feature of asbestos. According to the author, asbestos is a generic name for six needle-shaped minerals that possess high tensile strengths, flexibility, and resistance to chemical and thermal degradation. These minerals are actinolite, amosite, anthophyllite, chrysolite, crocilodite and tremolite. Asbestos is used for strengthening concrete pipe, plastic components, and gypsum plasters.

  20. Potassium Solubilization in Fungal Degradation of Aluminosilicate Minerals

    NASA Astrophysics Data System (ADS)

    Teng, H.; Lian, B.

    2007-12-01

    Potassium is an essential soil nutrient that performs a multitude of important biological functions to maintain plant growth and health. However, plants cannot directly use mineralic potassium. Only those that are released by weathering or dissolved in soil water are available for plants' nutrient uptake. On the other hand, microorganisms and related biological activities often play critical roles in mineral weathering and hence participate heavily in the geochemical cycles of nutrient elements. Here, we study the microbial release of potassium from K-bearing minerals orthoclase and illite. A strain of thermophilic fungus A. fumigatus was cultured with a mixture of the minerals to determine if microbe-mineral interactions enhance the solubilization of mineralic potassium. Experiments were carried in two settings, one with the mineral grains and the fungal cells in direct contact, and the other employing a membrane (pore size 0.22 um) to separate the two. Measurements over a period of 30 days showed that, irrespective of the experimental setup, the concentration of free K in the culture was drastically higher than those in any of the control experiments where no living organism was present. Moreover, the occurrence of mineral-cell physical contact enhanced potassium release by an additional factor of 3 to 4 in comparison to the separation experiments. For contact experiments, Electron Probe Microanalysis revealed the formation of mycelium-mineral aggregates, and Atomic Force Microscopy imaging further indicated the possible ingestion of mineral particles by the fungus cells. Contrasting to what was observed and expected in control experiments, the potassium solubilization rate showed a positive dependence upon pH when fungi and minerals were mixed directly, and exhibited no correlations with solution acidity if cell-rock contact was restrained. These results appear to suggest that A. fumigatus promoted potassium release by means of at least three likely routes, one

  1. Chemical Bonding in Sulfide Minerals

    SciTech Connect

    Vaughan, David J.; Rosso, Kevin M.

    2006-08-01

    An understanding of chemical bonding and electronic structure in sulfide minerals is central to any attempt at understanding their crystal structures, stabilities and physical properties. It is also an essential precursor to understanding reactivity through modeling surface structure at the molecular scale. In recent decades, there have been remarkable advances in first principles (ab initio) methods for the quantitative calculation of electronic structure. These advances have been made possible by the very rapid development of high performance computers. Several review volumes that chart the applications of these developments in mineralogy and geochemistry are available (Tossell and Vaughan, 1992; Cygan and Kubicki, 2001). An important feature of the sulfide minerals is the diversity of their electronic structures, as evidenced by their electrical and magnetic properties (see Pearce et al. 2006, this volume). Thus, sulfide minerals range from insulators through semiconductors to metals, and exhibit every type of magnetic behavior. This has presented problems for those attempting to develop bonding models for sulfides, and also led to certain misconceptions regarding the kinds of models that may be appropriate. In this chapter, chemical bonding and electronic structure models for sulfides are reviewed with emphasis on more recent developments. Although the fully ab initio quantitative methods are now capable of a remarkable degree of sophistication in terms of agreement with experiment and potential to interpret and predict behavior with varying conditions, both qualitative and more simplistic quantitative approaches will also be briefly discussed. This is because we believe that the insights which they provide are still helpful to those studying sulfide minerals. In addition to the application of electronic structure models and calculations to solid sulfides, work on sulfide mineral surfaces (Rosso and Vaughan 2006a,b) and solution complexes and clusters (Rickard

  2. Quantifying elemental compositions of primary minerals from granitic rocks and saprolite within the Santa Catalina Mountain Critical Zone Observatory

    NASA Astrophysics Data System (ADS)

    Lybrand, R. A.; Rasmussen, C.

    2011-12-01

    Granitic terrain comprises a significant area of the earth's land surface (>15%). Quantifying weathering processes involved in the transformation of granitic rock to saprolite and soil is central to understanding landscape evolution in these systems. The quantification of primary mineral composition is important for assessing subsequent mineral transformations and soil production. This study focuses on coupling detailed analysis of primary mineral composition to soil development across an array of field sites sampled from the Santa Catalina Mountain Critical Zone observatory (SCM-CZO) environmental gradient. The gradient spans substantial climate-driven shifts in vegetation, ranging from desert scrub to mixed conifer forests. The parent material is a combination of Precambrian and Tertiary aged granites and quartz diorite. Primary mineral type and composition are known to vary among the various aged granitic materials and this variability is hypothesized to manifest as significant variation in regolith forming processes across the SCM-CZO. To address this variability, the mineral composition and mineral formulae of rock and saprolite samples were determined by electron microprobe chemical analyses. The rocks were pre-dominantly quartz, biotite, muscovite, orthoclase and calcium/sodium-rich plagioclase feldspars. Trace minerals observed in the samples included sphene, rutile, zircon, garnet, ilmenite, and apatite. Mineral formulae from electron microprobe analyses were combined with quantitative x-ray diffraction (QXRD) and x-ray fluorescence (XRF) data to quantify both primary and secondary mineralogical components in soil profiles from each of the field sites. Further, electron microprobe analyses of <2mm mixed conifer saprolite revealed weathered plagioclase grains coated with clay-sized particles enriched in silica and aluminum (~25% and 15%, respectively), suggesting kaolin as the secondary phase. The coatings were interspersed within each plagioclase grain, a

  3. The MINER$\

    SciTech Connect

    Perdue, G.N.; Bagby, L.; Baldin, B.; Gingu, C.; Olsen, J.; Rubinov, P.; Schulte, E.C.; Bradford, R.; Brooks, W.K.; Caicedo, D.A.M.; Castromonte, C.M.; /Rio de Janeiro, CBPF /Rochester U.

    2012-09-01

    MINERvA (Main INjector ExpeRiment v-A) is a new few-GeV neutrino cross-section experiment that began taking data in the FNAL NuMI (Fermi National Accelerator Laboratory Neutrinos at the Main Injector) beam-line in March of 2010. MINERvA employs a fine-grained scintillator detector capable of complete kinematic characterization of neutrino interactions. This paper describes the MINERvA data acquisition system (DAQ) including the readout electronics, software, and computing architecture.

  4. New Minerals and Science.

    ERIC Educational Resources Information Center

    Birch, William D.

    1997-01-01

    Defines geodiversity, compares it to biodiversity, and discusses the mineral classification system. Charts the discovery of new minerals in Australia over time and focuses on uses of these minerals in technological advances. (DDR)

  5. Rocks and Minerals.

    ERIC Educational Resources Information Center

    Naturescope, 1987

    1987-01-01

    Provides background information on rocks and minerals, including the unique characteristics of each. Teaching activities on rock-hunting and identification, mineral configurations, mystery minerals, and growing crystals are provided. Reproducible worksheets are included for two of the activities. (TW)

  6. Mineral spirits poisoning

    MedlinePlus

    Mineral spirits are liquid chemicals used to thin paint and as a degreaser. Mineral spirits poisoning occurs ... be found in: Mineral spirits ( Stoddard solvent ) Some paints Some floor and furniture waxes and polishes Some ...

  7. Local unitary transformation method for large-scale two-component relativistic calculations. II. Extension to two-electron Coulomb interaction

    NASA Astrophysics Data System (ADS)

    Seino, Junji; Nakai, Hiromi

    2012-10-01

    The local unitary transformation (LUT) scheme at the spin-free infinite-order Douglas-Kroll-Hess (IODKH) level [J. Seino and H. Nakai, J. Chem. Phys. 136, 244102 (2012), 10.1063/1.4729463], which is based on the locality of relativistic effects, has been extended to a four-component Dirac-Coulomb Hamiltonian. In the previous study, the LUT scheme was applied only to a one-particle IODKH Hamiltonian with non-relativistic two-electron Coulomb interaction, termed IODKH/C. The current study extends the LUT scheme to a two-particle IODKH Hamiltonian as well as one-particle one, termed IODKH/IODKH, which has been a real bottleneck in numerical calculation. The LUT scheme with the IODKH/IODKH Hamiltonian was numerically assessed in the diatomic molecules HX and X2 and hydrogen halide molecules, (HX)n (X = F, Cl, Br, and I). The total Hartree-Fock energies calculated by the LUT method agree well with conventional IODKH/IODKH results. The computational cost of the LUT method is reduced drastically compared with that of the conventional method. In addition, the LUT method achieves linear-scaling with respect to the system size and a small prefactor.

  8. Microorganisms meet solid minerals: interactions and biotechnological applications.

    PubMed

    Ng, Daphne H P; Kumar, Amit; Cao, Bin

    2016-08-01

    In natural and engineered environments, microorganisms often co-exist and interact with various minerals or mineral-containing solids. Microorganism-mineral interactions contribute significantly to environmental processes, including biogeochemical cycles in natural ecosystems and biodeterioration of materials in engineered environments. In this mini-review, we provide a summary of several key mechanisms involved in microorganism-mineral interactions, including the following: (i) solid minerals serve as substrata for biofilm development; (ii) solid minerals serve as an electron source or sink for microbial respiration; (iii) solid minerals provide microorganisms with macro or micronutrients for cell growth; and (iv) (semi)conductive solid minerals serve as extracellular electron conduits facilitating cell-to-cell interactions. We also highlight recent developments in harnessing microbe-mineral interactions for biotechnological applications. PMID:27338573

  9. Microorganisms meet solid minerals: interactions and biotechnological applications.

    PubMed

    Ng, Daphne H P; Kumar, Amit; Cao, Bin

    2016-08-01

    In natural and engineered environments, microorganisms often co-exist and interact with various minerals or mineral-containing solids. Microorganism-mineral interactions contribute significantly to environmental processes, including biogeochemical cycles in natural ecosystems and biodeterioration of materials in engineered environments. In this mini-review, we provide a summary of several key mechanisms involved in microorganism-mineral interactions, including the following: (i) solid minerals serve as substrata for biofilm development; (ii) solid minerals serve as an electron source or sink for microbial respiration; (iii) solid minerals provide microorganisms with macro or micronutrients for cell growth; and (iv) (semi)conductive solid minerals serve as extracellular electron conduits facilitating cell-to-cell interactions. We also highlight recent developments in harnessing microbe-mineral interactions for biotechnological applications.

  10. Indiction of Work Function in Mineral Electrostatic Migration

    NASA Astrophysics Data System (ADS)

    Li, X. Y.; Gan, H.; Mo, B.; Wang, S. J.; Tang, H.; Wei, G. F.; Zhao, Y.-Y. S.

    2016-08-01

    Our preliminary experiments measured WFs of olivine, plagioclase, pyroxene, ilmenite using the SPM. These mineral grains can be charged to several thousand positive electrons under solar UV irrdations.

  11. Lunar highland rocks - Element partitioning among minerals. II - Electron microprobe analyses of Al, P, Ca, Ti, Cr, Mn and Fe in olivine

    NASA Technical Reports Server (NTRS)

    Smith, J. V.; Hansen, E. C.; Steele, I. M.

    1980-01-01

    Lunar olivines from anorthosites, granulitic impactites, and rocks in the Mg-rich plutonic trend were subjected to electron probe measurements for Al, P, Ca, Ti, Cr and Mn, which show that the FeO/MnO ratio for lunar olivines lies between 80 and 110 with little difference among the rock types. The low values of Ca in lunar olivines indicate slow cooling to subsolidus temperatures, with blocking temperatures of about 750 C for 67667 and 1000 C for 60255,73-alpha determined by the Finnerty and Boyd (1978) experiments. An important paradox is noted in the low Ti content of Fe-rich olivines from anorthosites, although both Ti and Fe tend to become enriched in liquid during fractional distillation. Except for Ca and Mn, olivine from anorthosites has lower minor element values than other rock types. Formation from a chemically distinct system is therefore implied.

  12. Determinants of pathologic mineralization.

    PubMed

    Kirsch, Thorsten

    2008-01-01

    Physiologic mineralization is necessary for the formation of skeletal tissues and for their appropriate functions during adulthood. Mineralization has to be controlled and restricted to specific regions. If the mineralization process occurs in regions that normally do not mineralize, there can be severe consequences (pathologic or ectopic mineralization). Recent findings have indicated that physiologic and pathologic mineralization events are initiated by matrix vesicles, membrane-enclosed particles released from the plasma membranes of mineralization-competent cells. The understanding of how these vesicles are released from the plasma membrane and initiate the mineralization process may provide novel therapeutic strategies to prevent pathologic mineralization. In addition, other regulators (activators and inhibitors) of physiologic mineralization have been identified and characterized, and there is evidence that the same factors also contribute to the regulation of pathologic mineralization. Finally, programmed cell death (apoptosis) may be a contributor to physiologic mineralization and if occurring after tissue injury may induce pathologic mineralization and mineralization-related differentiation events in the injured and surrounding areas. This review describes how the understanding of mechanisms and factors regulating physiologic mineralization can be used to develop new therapeutic strategies to prevent pathologic or ectopic mineralization events.

  13. XCT analysis of the influence of melt strategies on defect population in Ti–6Al–4V components manufactured by Selective Electron Beam Melting

    SciTech Connect

    Tammas-Williams, S.; Zhao, H.; Léonard, F.; Derguti, F.; Todd, I.; Prangnell, P.B.

    2015-04-15

    Selective Electron Beam Melting (SEBM) is a promising powder bed Additive Manufacturing technique for near-net-shape manufacture of high-value titanium components. However without post-manufacture HIPing the fatigue life of SEBM parts is currently dominated by the presence of porosity. In this study, the size, volume fraction, and spatial distribution of the pores in model samples have been characterised in 3D, using X-ray Computed Tomography, and correlated to the process variables. The average volume fraction of the pores (< 0.2%) was measured to be lower than that usually observed in competing processes, such as selective laser melting, but a strong relationship was found with the different beam strategies used to contour, and infill by hatching, a part section. The majority of pores were found to be small spherical gas pores, concentrated in the infill hatched region; this was attributed to the lower energy density and less focused beam used in the infill strategy allowing less opportunity for gas bubbles to escape the melt pool. Overall, increasing the energy density or focus of the beam was found to correlate strongly to a reduction in the level of gas porosity. Rarer irregular shaped pores were mostly located in the contour region and have been attributed to a lack of fusion between powder particles. - Graphical abstract: Display Omitted - Highlights: • Vast majority of defects detected were small spherical gas pores. • Gas bubbles trapped in the powder granules expand and coalesce in the melt pool. • Pores have been shown not to be randomly distributed. • Larger and deeper melt pools give more opportunity for gas to escape. • Minor changes to melt strategy result in significant reductions in pore population.

  14. 21 CFR 177.2355 - Mineral reinforced nylon resins.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Mineral reinforced nylon resins. 177.2355 Section... as Components of Articles Intended for Repeated Use § 177.2355 Mineral reinforced nylon resins. Mineral reinforced nylon resins identified in paragraph (a) of this section may be safely used as...

  15. 21 CFR 177.2355 - Mineral reinforced nylon resins.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Mineral reinforced nylon resins. 177.2355 Section... as Components of Articles Intended for Repeated Use § 177.2355 Mineral reinforced nylon resins. Mineral reinforced nylon resins identified in paragraph (a) of this section may be safely used as...

  16. 21 CFR 177.2355 - Mineral reinforced nylon resins.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Mineral reinforced nylon resins. 177.2355 Section... as Components of Articles Intended for Repeated Use § 177.2355 Mineral reinforced nylon resins. Mineral reinforced nylon resins identified in paragraph (a) of this section may be safely used as...

  17. 21 CFR 177.2355 - Mineral reinforced nylon resins.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Mineral reinforced nylon resins. 177.2355 Section... as Components of Articles Intended for Repeated Use § 177.2355 Mineral reinforced nylon resins. Mineral reinforced nylon resins identified in paragraph (a) of this section may be safely used as...

  18. Protein- mediated enamel mineralization

    PubMed Central

    Moradian-Oldak, Janet

    2012-01-01

    Enamel is a hard nanocomposite bioceramic with significant resilience that protects the mammalian tooth from external physical and chemical damages. The remarkable mechanical properties of enamel are associated with its hierarchical structural organization and its thorough connection with underlying dentin. This dynamic mineralizing system offers scientists a wealth of information that allows the study of basic principals of organic matrix-mediated biomineralization and can potentially be utilized in the fields of material science and engineering for development and design of biomimetic materials. This chapter will provide a brief overview of enamel hierarchical structure and properties as well as the process and stages of amelogenesis. Particular emphasis is given to current knowledge of extracellular matrix protein and proteinases, and the structural chemistry of the matrix components and their putative functions. The chapter will conclude by discussing the potential of enamel for regrowth. PMID:22652761

  19. In Vitro Enzymatic Reduction Kinetics of Mineral Oxides by Membrane Fractions from Shewanella oneidensis MR-1

    SciTech Connect

    Ruebush,S.; Icopini, G.; Brantley, S.; Tien, M.

    2006-01-01

    This study documents the first example of in vitro solid-phase mineral oxide reduction by enzyme-containing membrane fractions. Previous in vitro studies have only reported the reduction of aqueous ions. Total membrane (TM) fractions from iron-grown cultures of Shewanella oneidensis MR-1 were isolated and shown to catalyze the reduction of goethite, hematite, birnessite, and ramsdellite/pyrolusite using formate. In contrast, nicotinamide adenine dinucleotide (NADH) and succinate cannot function as electron donors. The significant implications of observations related to this cell-free system are: (i) both iron and manganese mineral oxides are reduced by the TM fraction, but aqueous U(VI) is not; (ii) TM fractions from anaerobically grown, but not aerobically grown, cells can reduce the mineral oxides; (iii) electron shuttles and iron chelators are not needed for this in vitro reduction, documenting conclusively that reduction can occur by direct contact with the mineral oxide; (iv) electron shuttles and EDTA stimulate the in vitro Fe(III) reduction, documenting that exogenous molecules can enhance rates of enzymatic mineral reduction; and (v) multiple membrane components are involved in solid-phase oxide reduction. The membrane fractions, consisting of liposomes of cytoplasmic and outer membrane segments, contain at least 100 proteins including the enzyme that oxidizes formate, formate dehydrogenase. Mineral oxide reduction was inhibited by the addition of detergent Triton X-100, which solubilizes membranes and their associated proteins, consistent with the involvement of multiple electron carriers that are disrupted by detergent addition. In contrast, formate dehydrogenase activity was not inhibited by Triton X-100. The addition of anthraquinone-2,6-disulfonate (AQDS) and menaquinone-4 was unable to restore activity; however, menadione (MD) restored 33% of the activity. The addition of AQDS and MD to reactions without added detergent increased the rate of goethite

  20. Bone mineralization pathways during the rapid growth of embryonic chicken long bones.

    PubMed

    Kerschnitzki, Michael; Akiva, Anat; Ben Shoham, Adi; Asscher, Yotam; Wagermaier, Wolfgang; Fratzl, Peter; Addadi, Lia; Weiner, Steve

    2016-07-01

    The uptake and transport of ions from the environment to the site of bone formation is only partially understood and, for the most part, based on disparate observations in different animals. Here we study different aspects of the biomineralization pathways in one system, the rapidly forming long bones of the chicken embryo. We mainly used cryo-fixation and cryo-electron imaging to preserve the often unstable mineral phases in the tissues. We show the presence of surprisingly large amounts of mineral particles located inside membrane-delineated vesicles in the bone forming tissue between the blood vessels and the forming bone surface. Some of these particles are also located inside mitochondrial networks. The surfaces of the forming bones in the extracellular space contain abundant aggregates of amorphous calcium phosphate particles, but these are not enveloped by vesicle membranes. In the bone resorbing region, osteoclasts also contain many particles in both mitochondrial networks and within vesicles. Some of these particles are present also between cells. These observations, together with the previously reported observation that CaP mineral particles inside membranes are present in blood vessels, leads us to the conclusion that important components of the bone mineralization pathways in rapidly forming chicken bone are dense phase mineral particles bound within membranes. It remains to be determined whether these mineral particles are transported to the site of bone formation in the solid state, fluid state or dissolve and re-precipitate. PMID:27108185

  1. Bone mineralization pathways during the rapid growth of embryonic chicken long bones.

    PubMed

    Kerschnitzki, Michael; Akiva, Anat; Ben Shoham, Adi; Asscher, Yotam; Wagermaier, Wolfgang; Fratzl, Peter; Addadi, Lia; Weiner, Steve

    2016-07-01

    The uptake and transport of ions from the environment to the site of bone formation is only partially understood and, for the most part, based on disparate observations in different animals. Here we study different aspects of the biomineralization pathways in one system, the rapidly forming long bones of the chicken embryo. We mainly used cryo-fixation and cryo-electron imaging to preserve the often unstable mineral phases in the tissues. We show the presence of surprisingly large amounts of mineral particles located inside membrane-delineated vesicles in the bone forming tissue between the blood vessels and the forming bone surface. Some of these particles are also located inside mitochondrial networks. The surfaces of the forming bones in the extracellular space contain abundant aggregates of amorphous calcium phosphate particles, but these are not enveloped by vesicle membranes. In the bone resorbing region, osteoclasts also contain many particles in both mitochondrial networks and within vesicles. Some of these particles are present also between cells. These observations, together with the previously reported observation that CaP mineral particles inside membranes are present in blood vessels, leads us to the conclusion that important components of the bone mineralization pathways in rapidly forming chicken bone are dense phase mineral particles bound within membranes. It remains to be determined whether these mineral particles are transported to the site of bone formation in the solid state, fluid state or dissolve and re-precipitate.

  2. Microbial Community Acquisition of Nutrients from Mineral Surfaces. Final Report

    SciTech Connect

    Hochella, M. F.

    2003-06-03

    Minerals and microbes undergo complex interactions in nature that impact broad aspects of near-surface Earth chemistry. Our primary objective in this project was to gain insight into how microbial species and communities acquire critical but tightly held nutrients residing on or within minerals common in rocks and soils, and to quantitatively study related microbe-mineral interactions including cell adhesion, electron transfer, and siderophore-mineral interaction processes.

  3. Energy-conserving reactions in phosphorylating electron-transport particles from Nitrobacter winogradskyi. Activation of nitrite oxidation by the electrical component of the protonmotive force.

    PubMed Central

    Cobley, J G

    1976-01-01

    1. In electron-transport particles (ET particles) prepared from Nitrobacter winogradskyi, the uncoupling agent carbonyl cyanide phenylhydrazone increased the rate of NADH oxidation but decreased the rate of oxidation of NO2-. Its effectiveness in stimulating NADH oxidation closely paralleled its effectiveness in inhibiting NO2- oxidation. 2. In the presence of ADP and phosphate the oxidation of NADH was stimulated, whereas the oxidation of NO2- was inhibited. In the presence of excess of Pi the concentration dependence with respect to ADP was the same for acceleration of NADH oxidation and inhibition of NO2- oxidation. 3. Oligomycin inhibited NADH oxidation and stimulated the oxidation of NO2-. The concentration of oligomycin required to produce half-maximal effect in both systems was the same. 4. The apparent Km for NO2- was not affected by ADP together with Pi, by uncoupling agent or by oligomycin. 5. With NADH as substrate, classical respiratory control was observed. With NO2- as substrate the respiratory-control ratio was less than unity. 6. A reversible uptake of H+ accompanied the oxidation of NO2- by ET particles. 7. In the presence of NH4Cl or cyclohexylamine hydrochloride, H+ uptake was abolished and increased rates of NO2- oxidation were observed. When valinomycin was present in the reaction medium, low concentrations of NH4Cl inhibited NO2- oxidation. 8. Pretreatment of ET particles with oligomycin enhanced the stimulation of NO2- oxidation induced by NH4Cl or by cyclohexylamine hydrochloride. Pretreatment with the uncoupler carbonyl cyanide phenylhydrazone prevented these stimulations. 9. In the presence of dianemycin together with K+, the uptake of H+ was abolished and the rate of NO2- oxidation was increased. In contrast, in the presence of valinomycin together with K+, the uptake of H+ was increased, and the rate of NO2- oxidation decreased. 10. Sodium tetraphenylboron was found to be an inhibitor of NO2- oxidation, but caused a stimulation of NADH

  4. Minerals in the Foods Eaten by Mountain Gorillas (Gorilla beringei)

    PubMed Central

    Cancelliere, Emma C.; DeAngelis, Nicole; Nkurunungi, John Bosco; Raubenheimer, David; Rothman, Jessica M.

    2014-01-01

    Minerals are critical to an individual’s health and fitness, and yet little is known about mineral nutrition and requirements in free-ranging primates. We estimated the mineral content of foods consumed by mountain gorillas (Gorilla beringei beringei) in the Bwindi Impenetrable National Park, Uganda. Mountain gorillas acquire the majority of their minerals from herbaceous leaves, which constitute the bulk of their diet. However, less commonly eaten foods were sometimes found to be higher in specific minerals, suggesting their potential importance. A principal component analysis demonstrated little correlation among minerals in food items, which further suggests that mountain gorillas might increase dietary diversity to obtain a full complement of minerals in their diet. Future work is needed to examine the bioavailability of minerals to mountain gorillas in order to better understand their intake in relation to estimated needs and the consequences of suboptimal mineral balance in gorilla foods. PMID:25372712

  5. Minerals in the foods eaten by mountain gorillas (Gorilla beringei).

    PubMed

    Cancelliere, Emma C; DeAngelis, Nicole; Nkurunungi, John Bosco; Raubenheimer, David; Rothman, Jessica M

    2014-01-01

    Minerals are critical to an individual's health and fitness, and yet little is known about mineral nutrition and requirements in free-ranging primates. We estimated the mineral content of foods consumed by mountain gorillas (Gorilla beringei beringei) in the Bwindi Impenetrable National Park, Uganda. Mountain gorillas acquire the majority of their minerals from herbaceous leaves, which constitute the bulk of their diet. However, less commonly eaten foods were sometimes found to be higher in specific minerals, suggesting their potential importance. A principal component analysis demonstrated little correlation among minerals in food items, which further suggests that mountain gorillas might increase dietary diversity to obtain a full complement of minerals in their diet. Future work is needed to examine the bioavailability of minerals to mountain gorillas in order to better understand their intake in relation to estimated needs and the consequences of suboptimal mineral balance in gorilla foods.

  6. Does the preferential microbial colonisation of ferromagnesian minerals affect mineral weathering in soil?

    PubMed

    Wilson, Michael J; Certini, Giacomo; Campbell, Colin D; Anderson, Ian C; Hillier, Stephen

    2008-09-01

    Fungal activity is thought to play a direct and effective role in the breakdown and dissolution of primary minerals and in the synthesis of clay minerals in soil environments, with important consequences for plant growth and ecosystem functioning. We have studied primary mineral weathering in volcanic soils developed on trachydacite in southern Tuscany using a combination of qualitative and quantitative mineralogical and microbiological techniques. Specifically, we characterized the weathering and microbiological colonization of the magnetically separated ferromagnesian minerals (biotite and orthopyroxene) and non-ferromagnesian constituents (K-feldspar and volcanic glass) of the coarse sand fraction (250-1,000 microm). Our results show that in the basal horizons of the soils, the ferromagnesian minerals are much more intensively colonized by microorganisms than K-feldspar and glass, but that the composition of the microbial communities living on the two mineral fractions is similar. Moreover, X-ray diffraction, optical and scanning electron microscope observations show that although the ferromagnesian minerals are preferentially associated with an embryonic form of the clay mineral halloysite, they are still relatively fresh. We interpret our results as indicating that in this instance microbial activity, and particularly fungal activity, has not been an effective agent of mineral weathering, that the association with clay minerals is indirect, and that fungal weathering of primary minerals may not be as important a source of plant nutrients as previously claimed.

  7. TUCS/phosphate mineralization of actinides

    SciTech Connect

    Nash, K.L.

    1997-10-01

    This program has as its objective the development of a new technology that combines cation exchange and mineralization to reduce the concentration of heavy metals (in particular actinides) in groundwaters. The treatment regimen must be compatible with the groundwater and soil, potentially using groundwater/soil components to aid in the immobilization process. The delivery system (probably a water-soluble chelating agent) should first concentrate the radionuclides then release the precipitating anion, which forms thermodynamically stable mineral phases, either with the target metal ions alone or in combination with matrix cations. This approach should generate thermodynamically stable mineral phases resistant to weathering. The chelating agent should decompose spontaneously with time, release the mineralizing agent, and leave a residue that does not interfere with mineral formation. For the actinides, the ideal compound probably will release phosphate, as actinide phosphate mineral phases are among the least soluble species for these metals. The most promising means of delivering the precipitant would be to use a water-soluble, hydrolytically unstable complexant that functions in the initial stages as a cation exchanger to concentrate the metal ions. As it decomposes, the chelating agent releases phosphate to foster formation of crystalline mineral phases. Because it involves only the application of inexpensive reagents, the method of phosphate mineralization promises to be an economical alternative for in situ immobilization of radionuclides (actinides in particular). The method relies on the inherent (thermodynamic) stability of actinide mineral phases.

  8. Citrate bridges between mineral platelets in bone.

    PubMed

    Davies, Erika; Müller, Karin H; Wong, Wai Ching; Pickard, Chris J; Reid, David G; Skepper, Jeremy N; Duer, Melinda J

    2014-04-01

    We provide evidence that citrate anions bridge between mineral platelets in bone and hypothesize that their presence acts to maintain separate platelets with disordered regions between them rather than gradual transformations into larger, more ordered blocks of mineral. To assess this hypothesis, we take as a model for a citrate bridging between layers of calcium phosphate mineral a double salt octacalcium phosphate citrate (OCP-citrate). We use a combination of multinuclear solid-state NMR spectroscopy, powder X-ray diffraction, and first principles electronic structure calculations to propose a quantitative structure for this material, in which citrate anions reside in a hydrated layer, bridging between apatitic layers. To assess the relevance of such a structure in native bone mineral, we present for the first time, to our knowledge, (17)O NMR data on bone and compare them with (17)O NMR data for OCP-citrate and other calcium phosphate minerals relevant to bone. The proposed structural model that we deduce from this work for bone mineral is a layered structure with thin apatitic platelets sandwiched between OCP-citrate-like hydrated layers. Such a structure can explain a number of known structural features of bone mineral: the thin, plate-like morphology of mature bone mineral crystals, the presence of significant quantities of strongly bound water molecules, and the relatively high concentration of hydrogen phosphate as well as the maintenance of a disordered region between mineral platelets.

  9. Investigation on mineralization behaviour of Type I collagen and noncollageneous extracellular matrix protein immobilized on polymer thin film

    NASA Astrophysics Data System (ADS)

    Ba, Xiaolan; Kristal, Ariella; Dimisi, Elaine; Rafailovich, Miriam

    2009-03-01

    The effects of the components of extracellular matrix on the bone formation and the kinetics of crystal growth of calcium phosphate have remained unknown. Here we reported a method to investigate the role of Type I collagen and the interactions with other ECM proteins such as fibronectin and elastin during biomineralization process. The early stage of mineralization was characterized by atomic force microscopy (AFM) and shear modulation force microscopy (SMFM). The late stage of mineralization was investigated by scanning electron microscopy (SEM), grazing incident x-ray diffraction (GIXD). The results showed the calcium phosphate biomineralization only occurred when the collagen interacted with fibronectin or elastin.

  10. Component analyses of urinary nanocrystallites of uric acid stone formers by combination of high-resolution transmission electron microscopy, fast Fourier transformation, energy dispersive X-ray spectroscopy, X-ray diffraction and Fourier transform infrared spectroscopy.

    PubMed

    Sun, Xin-Yuan; Xue, Jun-Fa; Xia, Zhi-Yue; Ouyang, Jian-Ming

    2015-06-01

    This study aimed to analyse the components of nanocrystallites in urines of patients with uric acid (UA) stones. X-ray diffraction (XRD), Fourier transform infrared spectroscopy, high-resolution transmission electron microscopy (HRTEM), fast Fourier transformation (FFT) of HRTEM, and energy dispersive X-ray spectroscopy (EDS) were performed to analyse the components of these nanocrystallites. XRD and FFT showed that the main component of urinary nanocrystallites was UA, which contains a small amount of calcium oxalate monohydrate and phosphates. EDS showed the characteristic absorption peaks of C, O, Ca and P. The formation of UA stones was closely related to a large number of UA nanocrystallites in urine. A combination of HRTEM, FFT, EDS and XRD analyses could be performed accurately to analyse the components of urinary nanocrystallites.

  11. Ceramic component for electrodes

    DOEpatents

    Marchant, David D.

    1979-01-01

    A ceramic component suitable for preparing MHD generator electrodes consists of HfO.sub.2 and sufficient Tb.sub.4 O.sub.7 to stabilize at least 60 volume percent of the HfO.sub.2 into the cubic structure. The ceramic component may also contain a small amount of PrO.sub.2, Yb.sub.2 O.sub.3 or a mixture of both to improve stability and electronic conductivity of the electrode. The component is highly resistant to corrosion by molten potassium seed and molten coal slag in the MHD fluid and exhibits both ionic and electronic conductivity.

  12. Comparison of marginal adaptation of mineral trioxide aggregate, glass ionomer cement and intermediate restorative material as root-end filling materials, using scanning electron microscope: An in vitro study

    PubMed Central

    Gundam, Sirisha; Patil, Jayaprakash; Venigalla, Bhuvan Shome; Yadanaparti, Sravanthi; Maddu, Radhika; Gurram, Sindhura Reddy

    2014-01-01

    Aim: The present study compares the marginal adaption of Mineral Trioxide Aggregate (MTA), Glass Ionomer Cement (GIC) and Intermediate Restorative Material (IRM) as root-end filling materials in extracted human teeth using Scanning Electron Microscope (SEM). Materials and Methods: Thirty single rooted human teeth were obturated with Gutta-percha after cleaning and shaping. Apical 3 mm of roots were resected and retrofilled with MTA, GIC and IRM. One millimeter transverse section of the retrofilled area was used to study the marginal adaptation of the restorative material with the dentin. Mounted specimens were examined using SEM at approximately 15 Kv and 10-6 Torr under high vacuum condition. At 2000 X magnification, the gap size at the material-tooth interface was recorded at 2 points in microns. Statistical Analysis: One way ANOVA Analysis of the data from the experimental group was carried out with gap size as the dependent variable, and material as independent variable. Results: The lowest mean value of gap size was recorded in MTA group (0.722 ± 0.438 μm) and the largest mean gap in GIC group (1.778 ± 0.697 μm). Conclusion: MTA showed least gap size when compared to IRM and GIC suggesting a better marginal adaptation. PMID:25506146

  13. Altered matrix mineralization in a case of a sclerosing osteosarcoma.

    PubMed

    Hofstaetter, Jochen G; Roschger, Andreas; Puchner, Stephan E; Dominkus, Martin; Sulzbacher, Irene; Windhager, Reinhard; Klaushofer, Klaus; Roschger, Paul

    2013-04-01

    Little is known about the tumor matrix mineralization of highly sclerotic osteosarcoma. We used quantitative backscattered electron imaging (qBEI) to determine the Bone mineralization density distribution (BMDD) of a highly sclerosing osteosarcoma of the proximal tibia as well as adjacent normal bone of a 10-year-old girl following chemotherapy according to the EURAMOS-1 protocol. Data were compared to recently published normative reference data for young individuals. Backscattered electron imaging of the tumor region revealed a dense accumulation of mineralized tumor bone matrix (up to 90% of the medullar space). The BMDD was shifted tremendously towards higher matrix mineralization (CaMean +18.5%, CaPeak +22.5%, CaHigh +100 fold) compared to normal bone. Additionally the BMDD became much wider, indicating a higher heterogeneity in mineralization (CaWidth +40%). In contrast to lamellar bone, which mineralizes via a mineralization front, the mineralization of the tumor matrix starts by randomly distributed spots of mineral clusters fusing together to a highly mineralized non-lamellar bone matrix. We also found an altered BMDD of the patient's normal bone when compared with the reference BMDD of young individuals. In conclusion this high radiodensity region of the sclerosing sarcoma is not only due to the high amount of tumor matrix but also to its high mineralization density. Chemotherapy may lead to altered matrix mineralization of normal bone due to suppression of bone turnover. The mechanism of matrix mineralization in a sclerosing osteosarcoma warrants further studies.

  14. Bartering for Minerals.

    ERIC Educational Resources Information Center

    May, Kathie

    2002-01-01

    Presents an activity in which students are assigned occupations that rely on specific minerals. To obtain the needed minerals, students learn how to trade services and commodities. Includes details on preparation, modeling behaviors, and printed materials. (DDR)

  15. Application of singular value decomposition (SVD) in extraction of gravity components indicating the deeply and shallowly buried granitic complex associated with tin polymetallic mineralization in the Gejiu tin ore field, Southwestern China

    NASA Astrophysics Data System (ADS)

    Chen, Yongqing; Zhang, Lina; Zhao, Binbin

    2015-12-01

    The Gejiu tin polymetallic ore deposit, located at the westernmost end of the Cathaysia Block, is one of the largest tin polymetallic ore deposits in the world. It is associated with a magmatic-hydrothermal ore-forming system triggered by the deeply buried geological structures and concealed granites. A singular value decomposition (SVD) program on a MATLAB platform was effectively used to extract deeply buried geological information reflecting deep-seated geological structures and the concealed granites by decomposing gravity signals within the Gejiu tin polymetallic ore field. Firstly, the gravity signals were decomposed into a few components with different eigenvalues using a singular value decomposition (SVD) approach. Secondly, the thresholds between the eigenvalues of gravity components reflecting deeply and shallowly buried ore-controlling geological structures and/or geological bodies were established by a multifractal method. Finally, the images of gravity components reflecting deeply and shallowly buried ore-controlling geological structures and/or geological bodies were reconstituted. This yielded two layers of significant two dimensional singular value gravity component images that indicate deeply and shallowly buried ore-controlling geological structures and/or geological bodies, respectively. The deep layer of gravity component image reveals a negative gravity anomaly (I) which indicates that the granites exposed in the west ore field, bounded by the Gejiu Fault, may be extended to the east ore field at depth, forming concealed granites (Fig. 4). The shallow layer of gravity component image reveals a structural framework created by two groups of NW-trending and three groups of NE-trending positive gravity component images defining two negative gravity anomalies (I and II), which may reflect existence of the exposed granites in the western ore field (I) and the concealed granites in the eastern ore field (II) (Figs. 5 and 6). Almost all tin

  16. Potential health risks from the use of fibrous mineral absorption granulates.

    PubMed Central

    Rödelsperger, K; Brückel, B; Manke, J; Woitowitz, H J; Pott, F

    1987-01-01

    Attapulgite (palygorskite) and sepiolite are fibrous clay minerals used commercially as components in a wide variety of products including oil and grease adsorbents, carriers for pharmaceuticals, cosmetics, and pesticides. They are also components of drilling muds and animal litter and they are used as paint thickeners. The current annual worldwide production of these minerals exceeds one million tons. Although fibrous in nature, the fibre length may vary greatly depending on the location of the geological deposits. American attapulgite is short (0.1-2.5 micron in length, median of 0.4 micron) but palygorskite from other parts of the world is much longer (30% longer than 5 micron). Several samples of these materials have been submitted to scanning transmission electron microscopy (STEM). This paper reports the results of microscopic evaluations and makes a comparison with the data from experimental carcinogenicity studies and it is concluded that fibre length is a most important carcinogenic property. Images PMID:2954581

  17. Potential health risks from the use of fibrous mineral absorption granulates.

    PubMed

    Rödelsperger, K; Brückel, B; Manke, J; Woitowitz, H J; Pott, F

    1987-05-01

    Attapulgite (palygorskite) and sepiolite are fibrous clay minerals used commercially as components in a wide variety of products including oil and grease adsorbents, carriers for pharmaceuticals, cosmetics, and pesticides. They are also components of drilling muds and animal litter and they are used as paint thickeners. The current annual worldwide production of these minerals exceeds one million tons. Although fibrous in nature, the fibre length may vary greatly depending on the location of the geological deposits. American attapulgite is short (0.1-2.5 micron in length, median of 0.4 micron) but palygorskite from other parts of the world is much longer (30% longer than 5 micron). Several samples of these materials have been submitted to scanning transmission electron microscopy (STEM). This paper reports the results of microscopic evaluations and makes a comparison with the data from experimental carcinogenicity studies and it is concluded that fibre length is a most important carcinogenic property. PMID:2954581

  18. Separation of the electron and proton cosmic-ray components by means of a calorimeter in the PAMELA satellite-borne experiment for the case of particle detection within a large aperture

    SciTech Connect

    Karelin, A. V. Borisov, S. V.; Voronov, S. A.; Malakhov, V. V.

    2013-06-15

    The PAMELA satellite-borne experiment is designed to study cosmic rays over a broad energy range. The apparatus has been in near-Earth cosmic space from June 2006 to the present time. It is equipped with a magnetic spectrometer for determining the sign of the particle charge and rigidity. In solving some problems, however, information from the magnetic spectrometer becomes inaccessible, so that it is necessary to employ a calorimeter to separate the electron and nuclear cosmic-ray components. A procedure for separating these components for particles arriving off the magnetic-spectrometer aperture is considered.

  19. Age and disease-related changes in the mineral of bone.

    PubMed

    Grynpas, M

    1993-01-01

    Bone mineralization changes with age and disease. The distribution of mineral particles in a given bone (mineralization profile) has been studied using density fractionation as well as microradiography and electron backscattering imaging. The biological determinant of mineralization is the rate of turnover. During rapid growth and periods of high remodeling, mineralization is shifted towards lower mineral density (hypomineralization). During aging and periods of low remodeling, mineralization is shifted towards higher mineral densities (hypermineralization). Chemicals can also influence the mineralization profile of bone. Fluoride induces hypermineralization by stabilizing the apatite lattice and reducing bone mineral solubility, whereas strontium induces hypomineralization by loosening the apatite lattice and increasing bone mineral solubility. Drugs such as bisphosphonates induce hypermineralization by inhibiting resorption and acting as crystal poison. Finally, mineralization can be impaired by defects as in rickets and osteomalacia or made excessive by continuous accretion of mineral without resorption as in osteopetrosis. PMID:8275381

  20. Authigenic minerals: Biologically influenced and induced organomineralization

    NASA Astrophysics Data System (ADS)

    Dupraz, Christophe

    2016-04-01

    Organominerals are minerals precipitated by interactions with organic matter without enzymatic control. Organomineralization of authigenic carbonate minerals depends on two key components: (1) the "carbonate alkalinity engine" impacting the calcium carbonate saturation index and (2) the organic matrix comprised of extracellular organic matter (EOM), which provides a template for carbonate nucleation. The alkalinity engine can be "intrinsic" when microbial metabolisms increase supersaturation or lower the kinetic barrier of precipitation, or "extrinsic" when the physicochemical environment creates the conditions for mineral formation. The organic matrix produced by various communities within the microbial mats is known to influence nucleation, morphology and mineralogy of minerals through binding of cations. By playing with these two key components, three types of authigenic minerals can be formed: (1) a purely physicochemical precipitation on an abiotic substrate, (2) a precipitation "influenced" by the presence of an organic matrix but resulting from a physicochemical forcing (environmentally driven), or (3) a "microbially-induced" precipitation, in which both supersaturation and organic matrix are resulting from microbial activity. In this keynote, we will review important processes involved in the precipitation of authigenic carbonate minerals in modern microbial mats and open the discussion on the potential use of authigenic carbonate minerals as biosignatures in the fossil record.

  1. A revised dosimetric characterization of the model S700 electronic brachytherapy source containing an anode-centering plastic insert and other components not included in the 2006 model

    SciTech Connect

    Hiatt, Jessica R.; Davis, Stephen D.; Rivard, Mark J.

    2015-06-15

    Purpose: The model S700 Axxent electronic brachytherapy source by Xoft, Inc., was characterized by Rivard et al. in 2006. Since then, the source design was modified to include a new insert at the source tip. Current study objectives were to establish an accurate source model for simulation purposes, dosimetrically characterize the new source and obtain its TG-43 brachytherapy dosimetry parameters, and determine dose differences between the original simulation model and the current model S700 source design. Methods: Design information from measurements of dissected model S700 sources and from vendor-supplied CAD drawings was used to aid establishment of an updated Monte Carlo source model, which included the complex-shaped plastic source-centering insert intended to promote water flow for cooling the source anode. These data were used to create a model for subsequent radiation transport simulations in a water phantom. Compared to the 2006 simulation geometry, the influence of volume averaging close to the source was substantially reduced. A track-length estimator was used to evaluate collision kerma as a function of radial distance and polar angle for determination of TG-43 dosimetry parameters. Results for the 50 kV source were determined every 0.1 cm from 0.3 to 15 cm and every 1° from 0° to 180°. Photon spectra in water with 0.1 keV resolution were also obtained from 0.5 to 15 cm and polar angles from 0° to 165°. Simulations were run for 10{sup 10} histories, resulting in statistical uncertainties on the transverse plane of 0.04% at r = 1 cm and 0.06% at r = 5 cm. Results: The dose-rate distribution ratio for the model S700 source as compared to the 2006 model exceeded unity by more than 5% for roughly one quarter of the solid angle surrounding the source, i.e., θ ≥ 120°. The radial dose function diminished in a similar manner as for an {sup 125}I seed, with values of 1.434, 0.636, 0.283, and 0.0975 at 0.5, 2, 5, and 10 cm, respectively. The radial dose

  2. Direct characterization of the energy level alignments and molecular components in an organic hetero-junction by integrated photoemission spectroscopy and reflection electron energy loss spectroscopy analysis.

    PubMed

    Yun, Dong-Jin; Shin, Weon-Ho; Bulliard, Xavier; Park, Jong Hwan; Kim, Seyun; Chung, Jae Gwan; Kim, Yongsu; Heo, Sung; Kim, Seong Heon

    2016-08-26

    A novel, direct method for the characterization of the energy level alignments at bulk-heterojunction (BHJ)/electrode interfaces on the basis of electronic spectroscopy measurements is proposed. The home-made in situ photoemission system is used to perform x-ray/ultraviolet photoemission spectroscopy (XPS/UPS), reflection electron energy loss spectroscopy (REELS) and inverse photoemission spectroscopy of organic-semiconductors (OSCs) deposited onto a Au substrate. Through this analysis system, we are able to obtain the electronic structures of a boron subphthalocyanine chloride:fullerene (SubPC:C60) BHJ and those of the separate OSC/electrode structures (SubPC/Au and C60/Au). Morphology and chemical composition analyses confirm that the original SubPC and C60 electronic structures remain unchanged in the electrodes prepared. Using this technique, we ascertain that the position and area of the nearest peak to the Fermi energy (EF = 0 eV) in the UPS (REELS) spectra of SubPC:C60 BHJ provide information on the highest occupied molecular orbital level (optical band gap) and combination ratio of the materials, respectively. Thus, extracting the adjusted spectrum from the corresponding SubPC:C60 BHJ UPS (REELS) spectrum reveals its electronic structure, equivalent to that of the C60 materials. This novel analytical approach allows complete energy-level determination for each combination ratio by separating its electronic structure information from the BHJ spectrum. PMID:27420635

  3. Direct characterization of the energy level alignments and molecular components in an organic hetero-junction by integrated photoemission spectroscopy and reflection electron energy loss spectroscopy analysis

    NASA Astrophysics Data System (ADS)

    Yun, Dong-Jin; Shin, Weon-Ho; Bulliard, Xavier; Park, Jong Hwan; Kim, Seyun; Chung, Jae Gwan; Kim, Yongsu; Heo, Sung; Kim, Seong Heon

    2016-08-01

    A novel, direct method for the characterization of the energy level alignments at bulk-heterojunction (BHJ)/electrode interfaces on the basis of electronic spectroscopy measurements is proposed. The home-made in situ photoemission system is used to perform x-ray/ultraviolet photoemission spectroscopy (XPS/UPS), reflection electron energy loss spectroscopy (REELS) and inverse photoemission spectroscopy of organic-semiconductors (OSCs) deposited onto a Au substrate. Through this analysis system, we are able to obtain the electronic structures of a boron subphthalocyanine chloride:fullerene (SubPC:C60) BHJ and those of the separate OSC/electrode structures (SubPC/Au and C60/Au). Morphology and chemical composition analyses confirm that the original SubPC and C60 electronic structures remain unchanged in the electrodes prepared. Using this technique, we ascertain that the position and area of the nearest peak to the Fermi energy (EF = 0 eV) in the UPS (REELS) spectra of SubPC:C60 BHJ provide information on the highest occupied molecular orbital level (optical band gap) and combination ratio of the materials, respectively. Thus, extracting the adjusted spectrum from the corresponding SubPC:C60 BHJ UPS (REELS) spectrum reveals its electronic structure, equivalent to that of the C60 materials. This novel analytical approach allows complete energy-level determination for each combination ratio by separating its electronic structure information from the BHJ spectrum.

  4. The organic-mineral interaction in mollusk shell

    NASA Astrophysics Data System (ADS)

    Metzler, Rebecca A.

    Macromolecules are a minority but important component of the minerals formed by living organisms, or biominerals. While many proteins from the nacre and prismatic layers of mollusk shells have been identified and sequenced, the molecular interaction, organization, and rearrangements of proteins upon organic-mineral bond formation, and the effect of this interaction on crystal formation, deformation, and orientation are poorly understood. To examine the organic-mineral interaction in mollusk shells, we prepared model systems consisting of calcium carbonate grown in the presence of synthetic mollusk shell polypeptides. X-ray absorption near-edge structure (XANES) spectroscopy and x-ray photoelectron emission microscopy (X-PEEM) were used to examine the electronic structure and bonding environment of both the surface and bulk of model biomineral crystals, thereby determining that the organic-mineral interaction is a series of events starting with bond formation and ending with the fully formed mineral. XANES spectra acquired from the model biomineral systems showed that upon organic-mineral bond formation both the crystal and the polypeptides exhibit bond and molecular structure alterations. We acquired XANES spectra from the surface of calcium carbonate crystals grown in the presence of six synthetic polypeptides sequenced after mollusk nacre proteins: AP7N, AP24N, N16N, asp1, asp2, and ACCN. All of these model biominerals gave similar results, namely the disruption of CO bonds in calcite and enhancement of the peaks associated with C-H bonds bonds in peptides, indicating disordering of the calcite crystal and ordering of the peptides upon binding. We also show that these changes do not occur when the acidic amino acids, Asp and Glu, are replaced in the N16N sequence with Asn and Gln, respectively, demonstrating the importance of carboxyl groups in organic-mineral bond formation. We examined the bulk crystal structure of crystals grown in the presence of N16N and asp

  5. Nanowires, Capacitors, and Other Novel Outer-Surface Components Involved in Electron Transfer to Fe(III) Oxides in Geobacter Species

    SciTech Connect

    Lovley, Derek, R.

    2008-12-22

    The overall goal of this project was to better understand the mechanisms by which Geobacter species transfer electrons outside the cell onto Fe(III) oxides. The rationale for this study was that Geobacter species are often the predominant microorganisms involved in in situ uranium bioremediation and the growth and activity of the Geobacter species during bioremediation is primarily supported by electron transfer to Fe(III) oxides. These studies greatly expanded the understanding of electron transfer to Fe(III). Novel concepts developed included the potential role of microbial nanowires for long range electron transfer in Geobacter species and the importance of extracytoplasmic cytochromes functioning as capacitors to permit continued electron transfer during the hunt for Fe(III) oxide. Furthermore, these studies provided target sequences that were then used in other studies to tract the activity of Geobacter species in the subsurface through monitoring the abundance of gene transcripts of the target genes. A brief summary of the major accomplishments of the project is provided.

  6. 30 CFR 56.11007 - Wooden components of ladders.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Wooden components of ladders. 56.11007 Section 56.11007 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... § 56.11007 Wooden components of ladders. Wooden components of ladders shall not be painted except...

  7. 30 CFR 56.11007 - Wooden components of ladders.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Wooden components of ladders. 56.11007 Section 56.11007 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... § 56.11007 Wooden components of ladders. Wooden components of ladders shall not be painted except...

  8. Mineralization by nanobacteria

    NASA Astrophysics Data System (ADS)

    Kajander, E. Olavi; Bjorklund, Michael; Ciftcioglu, Neva

    1998-07-01

    Nanobacteria are the smallest cell-walled bacteria, only recently discovered in human and cow blood and in commercial cell culture serum. In this study, we identified with energy-dispersive x-ray microanalysis and chemical analysis that all growth phases of nanobacteria produce biogenic apatite on their cell envelope. Fourier transform IR spectroscopy revealed the mineral as carbonate apatite. Previous models for stone formation have lead to a hypothesis that an elevated pH due to urease and/or alkaline phosphatase activity are important lithogenic factors. Our results indicate that carbonate apatite can be formed without these factors at pH 7.4 at physiological phosphate and calcium concentrations. Due to their specific macromolecules, nanobacteria can produce apatite very efficiency in media mimicking tissue fluids and glomerular filtrate and rapidly mineralizing most of available calcium and phosphate. This can be also monitored by (superscript 85)Sr incorporation and provides a unique model for in vitro studies on calcification. Recently, bacteria have been implicated in the formation of carbonate (hydroxy)fluorapatite in marine sediments. Apatite grains are found so commonly in sedimentary rocks that apatite is omitted in naming the stone. To prove that apatite and other minerals are formed by bacteria would implicate that the bacteria could be observed and their actions followed in stones. We have started to approach this in two ways. Firstly, by the use of sensitive methods for detecting specific bacterial components, like antigens, muramic acid and nucleic acids, that allow for detecting the presence of bacteria and, secondly, by follow-up of volatile bacterial metabolites observed by continuous monitoring with ion mobility spectrometry, IMCELL, working like an artificial, educatable smelling nose. The latter method might allow for remote real time detection of bacterial metabolism, a signature of life, in rocks via fractures of drillholes with or without

  9. Mineral commodity profiles: Germanium

    USGS Publications Warehouse

    Butterman, W.C.; Jorgenson, John D.

    2005-01-01

    Overview -- Germanium is a hard, brittle semimetal that first came into use a half-century ago as a semiconductor material in radar units and as the material from which the first transistor was made. Today it is used principally as a component of the glass in telecommunications fiber optics; as a polymerization catalyst for polyethylene terephthalate (PET), a commercially important plastic; in infrared (IR) night vision devices; and as a semiconductor and substrate in electronics circuitry. Most germanium is recovered as a byproduct of zinc smelting, although it also has been recovered at some copper smelters and from the fly ash of coal-burning industrial powerplants. It is a highly dispersed element, associated primarily with base-metal sulfide ores. In the United States, germanium is recovered from zinc smelter residues and manufacturing scrap and is refined by two companies at four germanium refineries. One of the four refineries is dedicated to processing scrap. In 2000, producers sold zone-refined (high-purity) germanium at about $1,250 per kilogram and electronic-grade germanium dioxide (GeO2) at $800 per kilogram. Domestic refined production was valued at $22 million. Germanium is a critical component in highly technical devices and processes. It is likely to remain in demand in the future at levels at least as high as those of 2000. U.S. resources of germanium are probably adequate to meet domestic needs for several decades.

  10. Determination of the electron energy distribution function in the plasma by means of numerical simulations of multiple harmonic components on a Langmuir probe characteristic—measurements in expanding microwave plasma

    NASA Astrophysics Data System (ADS)

    Jauberteau, J. L.; Jauberteau, I.

    2007-05-01

    A method is proposed to determine the electron energy distribution function (EEDF), which is related to the second derivative of the electrostatic probe characteristic by the Druyvesteyn theory. The method is based on the numerical simulation of the effect induced by a sinusoidal perturbation superimposed on to the dc voltage applied to the probe. This simulation generates a multiple harmonic components' signal over the rough experimental data. Each harmonic component can be isolated by means of finite impulse response filters. Then, the second derivative is deduced from the second harmonic component using the Taylor expansion. The efficiency of the multiple harmonic simulation method is proved first on simple models and second on a typical Langmuir probe characteristic recorded in a plasma-containing argon. This method is used to investigate expanding microwave plasma in the case of two different reactor configurations.

  11. Influence of bacteria on lanthanide and actinide transfer from specific soil components (humus, soil minerals and vitrified municipal solid waste incinerator bottom ash) to corn plants: Sr-Nd isotope evidence.

    PubMed

    Aouad, Georges; Stille, Peter; Crovisier, Jean-Louis; Geoffroy, Valérie A; Meyer, Jean-Marie; Lahd-Geagea, Majdi

    2006-11-01

    Experiments have been performed to test the stability of vitrified municipal solid waste (MSW) incinerator bottom ash under the presence of bacteria (Pseudomonas aeruginosa) and plants (corn). The substratum used for the plant growth was a humus-rich soil mixed with vitrified waste. For the first time, information on the stability of waste glasses in the presence of bacteria and plants is given. Results show that inoculated plant samples contained always about two times higher lanthanide and actinide element concentrations. Bacteria support the element transfer since plants growing in inoculated environment developed a smaller root system but have higher trace element concentrations. Compared with the substratum, plants are light rare earth element (LREE) enriched. The vitrified bottom ash has to some extent been corroded by bacteria and plant activities as indicated by the presence of Nd (REE) and Sr from the vitrified waste in the plants. (87)Sr/(86)Sr and (143)Nd/(144)Nd isotope ratios of plants and soil components allow the identification of the corroded soil components and confirm that bacteria accelerate the assimilation of elements from the vitrified bottom ash. These findings are of importance for landfill disposal scenarios, and similar experiments should be performed in order to better constrain the processes of microbially mediated alteration of the MSW glasses in the biosphere.

  12. Application of decision tree algorithm for identification of rock forming minerals using energy dispersive spectrometry

    NASA Astrophysics Data System (ADS)

    Akkaş, Efe; Çubukçu, H. Evren; Artuner, Harun

    2014-05-01

    Rapid and automated mineral identification is compulsory in certain applications concerning natural rocks. Among all microscopic and spectrometric methods, energy dispersive X-ray spectrometers (EDS) integrated with scanning electron microscopes produce rapid information with reliable chemical data. Although obtaining elemental data with EDS analyses is fast and easy by the help of improving technology, it is rather challenging to perform accurate and rapid identification considering the large quantity of minerals in a rock sample with varying dimensions ranging between nanometer to centimeter. Furthermore, the physical properties of the specimen (roughness, thickness, electrical conductivity, position in the instrument etc.) and the incident electron beam (accelerating voltage, beam current, spot size etc.) control the produced characteristic X-ray, which in turn affect the elemental analyses. In order to minimize the effects of these physical constraints and develop an automated mineral identification system, a rule induction paradigm has been applied to energy dispersive spectral data. Decision tree classifiers divide training data sets into subclasses using generated rules or decisions and thereby it produces classification or recognition associated with these data sets. A number of thinsections prepared from rock samples with suitable mineralogy have been investigated and a preliminary 12 distinct mineral groups (olivine, orthopyroxene, clinopyroxene, apatite, amphibole, plagioclase, K- feldspar, zircon, magnetite, titanomagnetite, biotite, quartz), comprised mostly of silicates and oxides, have been selected. Energy dispersive spectral data for each group, consisting of 240 reference and 200 test analyses, have been acquired under various, non-standard, physical and electrical conditions. The reference X-Ray data have been used to assign the spectral distribution of elements to the specified mineral groups. Consequently, the test data have been analyzed using

  13. Light-dependent regulation of photosynthesis genes in Rhodobacter sphaeroides 2.4.1 is coordinately controlled by photosynthetic electron transport via the PrrBA two-component system and the photoreceptor AppA.

    PubMed

    Happ, Hendrik N; Braatsch, Stephan; Broschek, Vera; Osterloh, Lisa; Klug, Gabriele

    2005-11-01

    Formation of the photosynthetic apparatus in Rhodobacter is regulated by oxygen tension and light intensity. Here we show that in anaerobically grown Rhodobacter cells a light-dependent increase in expression of the puc and puf operons encoding structural proteins of the photosynthetic complexes requires an active photosynthetic electron transport. The redox-sensitive CrtJ/PpsR repressor of photosynthesis genes, which was suggested to mediate electron transport-dependent signals, is not involved in this light-dependent signal chain. Our data reveal that the signal initiated in the photosynthetic reaction centre is transmitted via components of the electron transport chain and the PrrB/PrrA two-component system in Rhodobacter sphaeroides. Under blue light illumination in the absence of oxygen this signal leads to activation of photosynthesis genes and interferes with a blue-light repression mediated by the AppA photoreceptor and the PpsR transcriptional repressor in R. sphaeroides. Thus, light either sensed by a photoreceptor or initiating photosynthetic electron transport has opposite effects on the transcription of photosynthesis genes. Both signalling pathways involve redox-dependent steps that finally determine the effect of light on gene expression.

  14. A Model for the Ultrastructure of Bone Based on Electron Microscopy of Ion-Milled Sections

    PubMed Central

    McNally, Elizabeth A.; Schwarcz, Henry P.; Botton, Gianluigi A.; Arsenault, A. Larry

    2012-01-01

    The relationship between the mineral component of bone and associated collagen has been a matter of continued dispute. We use transmission electron microscopy (TEM) of cryogenically ion milled sections of fully-mineralized cortical bone to study the spatial and topological relationship between mineral and collagen. We observe that hydroxyapatite (HA) occurs largely as elongated plate-like structures which are external to and oriented parallel to the collagen fibrils. Dark field images suggest that the structures (“mineral structures”) are polycrystalline. They are approximately 5 nm thick, 70 nm wide and several hundred nm long. Using energy-dispersive X-ray analysis we show that approximately 70% of the HA occurs as mineral structures external to the fibrils. The remainder is found constrained to the gap zones. Comparative studies of other species suggest that this structural motif is ubiquitous in all vertebrates. PMID:22272230

  15. A Role for Antibiotics in Mineral Dissolution and Biofilm Physiology

    NASA Astrophysics Data System (ADS)

    Newman, D. K.

    2002-12-01

    Respiration by bacteria is remarkable due to their ability to use a variety of compounds, including insoluble minerals, as terminal electron acceptors. How bacteria solve the problem of breathing something that is solid is poorly understood, but recent evidence points to the role of redox active natural products in shuttling electrons between microbes and minerals. Given the ubiquity of these substances in natural waters and soils, we must now revisit previous conclusions about whether direct contact between microbes and minerals is necessary to promote reductive mineral dissolution. To explore the degree to which extracellular electron transfer catalyzes important biogeochemical processes, we are studying the types of molecules that function as electron shuttles, including redox active antibiotics. I will discuss my laboratory's current understanding of how interspecies exchange of these molecules promotes mineral dissolution, as well as our emerging hypotheses regarding their function in biofilms.

  16. An X-ray electron study of nanodisperse hydroxyapatite

    NASA Astrophysics Data System (ADS)

    Melikhov, I. V.; Teterin, Yu. A.; Rudin, V. N.; Teterin, A. Yu.; Maslakov, K. I.; Severin, A. V.

    2009-01-01

    Two states of surface valence electrons localized on faces with different molecular reliefs were observed for nanodisperse hydroxyapatite. Thermal treatment of nanocrystals caused a shift Δ E b = 0.5 eV of the spectrum of valence electrons on molecularly rough faces and a shift of 0.8 eV of the spectrum from smooth faces. Similar electron spectrum shifts were observed for sorption, in particular, of sodium succinate. These results are of importance for the diagnostics of various hydroxyapatite kinds, since hydroxyapatite is a constituent mineral component of living organisms, and for the synthesis of medicines with enhanced biological activity used in treatment of various bone diseases.

  17. Elastic Properties of Mantle Minerals

    NASA Astrophysics Data System (ADS)

    Duffy, T. S.; Stan, C. V.

    2012-12-01

    The most direct information about the interior structure of the Earth comes from seismic wave velocities. Interpretation of seismic data requires an understanding of how sound velocities and elastic properties of minerals vary with pressure, temperature, crystal structure, and composition as well as the role of anelasticity, melts, etc. More generally, elastic moduli are important for understanding many solid-state phenomena including mechanical stability, interatomic interactions, material strength, compressibility, and phase transition mechanisms. The database of mineral elasticity measurements has been growing rapidly in recent years. In this work, we report initial results of an ongoing survey of our current knowledge of mineral elasticity at both ambient conditions and high pressures and temperatures. The analysis is selective, emphasizing single crystal measurements but also incorporating polycrystalline measurements and volume compression data as appropriate. The goal is to synthesize our current understanding of mineral elasticity in terms of structure and composition, and to identify the major remaining needs for experimental and theoretical work. Clinopyroxenes (Cpx) provide an example of our approach. A wide range of clinopyroxene compositions are found geologically and Mg-, Ca-, and Na-rich clinopyroxenes are expected to be important components in the upper mantle. The single-crystal elastic properties of a number of endmember Cpx compositions have been measured and these exhibit a range of ~25% in shear velocity. Those with monovalent cations (spodumene, jadeite) in the M2 site exhibit the highest velocities while Fe-rich (hendenbergit, acmite) compositions have the lowest velocities. The effects on velocity due to a wide range of chemical substitutions can be defined, but there are important discrepancies and omissions in the database. New measurements of omphacites, intermediate diopside-hedenbergite compositions, aegerine/acmite, augite, etc. are

  18. Irradiation records in regolith materials, II: Solar wind and solar energetic particle components in helium, neon, and argon extracted from single lunar mineral grains and from the Kapoeta howardite by stepwise pulse heating

    NASA Astrophysics Data System (ADS)

    Palma, R. L.; Becker, R. H.; Pepin, R. O.; Schlutter, D. J.

    2002-09-01

    .'s (1993) SW estimate. Elemental ratios of He, Ne, and Ar initially released from grain-surface SW implantation zones are solar-like, as found earlier by Pepin et al. (1999). Gases evolved from these reservoirs at higher temperatures show evidence for perturbations from solar elemental compositions by prior He loss, thermal mobilization of excess Ne from fractionated SW components, or both. Attention in this second investigation was focused on estimating the isotopic compositions of both the SW and the more deeply sited SEP components in regolith grains. Several high-temperature "isotopic plateaus" - approximately constant isotopic ratios in gas fractions released over a number of consecutive heating steps - were observed in the close vicinities of the SEP ratios for He, Ne, and Ar reported by Benkert et al. (1993). Arguments presented in the text suggest that these plateaus are relatively free of interferences from multicomponent mixing artifacts that can mimic pure component signatures. Average SEP compositions derived from the stepped-heating plateau measurements are in remarkable agreement with the Zürich acid-etch values for all three gases.

  19. Reagan issues mineral policy

    NASA Astrophysics Data System (ADS)

    The National Materials and Minerals Program plan and report that President Reagan sent to Congress on April 5 aims to ‘decrease America's minerals vulnerability’ while reducing future dependence on potentially unstable foreign sources of minerals. These goals would be accomplished by taking inventory of federal lands to determine mineral potential; by meeting the stockpile goals set by the Strategic and Critical Material Stockpiling Act; and by establishing a business and political climate that would encourage private-sector research and development on minerals.Now that the Administration has issued its plan, the Subcommittee on Mines and Mining of the House Committee on Interior and Insular Affairs will consider the National Minerals Security Act (NMSA), which was introduced 1 year ago by subcommittee chairman Jim Santini (D-Nev.) [Eos, May 19, 1981, p. 497]. The bill calls for establishing a three-member White-House-level council to coordinate the development of a national minerals policy; amending tax laws to assist the mining industry to make capital investments to locate and produce strategic materials; and creating a revolving fund for the sale and purchase of strategic minerals. In addition, the NMSA bill would allow the secretary of the interior to make previously withdrawn public lands available for mineral development. The subcommittee will hold a hearing on the Administration's plan on May 11. Interior Secretary James Watt has been invited to testify.

  20. Cellular components of the immune barrier in the spinal meninges and dorsal root ganglia of the normal rat: immunohistochemical (MHC class II) and electron-microscopic observations.

    PubMed

    Braun, J S; Kaissling, B; Le Hir, M; Zenker, W

    1993-08-01

    This report deals with the distribution, morphology and specific topical relationships of bone-marrow-derived cells (free cells) in the spinal meninges and dorsal root ganglia of the normal rat. The morphology of these cells has been studied by transmission and scanning electron microscopy. Cells expressing the major histocompatibility complex (MHC) class II gene product have been recognized by immunofluorescence. At the level of the transmission electron microscope, free cells are found in all layers of the meninges. Many of them display characteristic ultrastructural features of macrophages, whereas others show a highly vacuolated cytoplasm and are endowed with many processes. These elements lack a conspicuous lysosomal system and might represent dendritic cells. Scanning electron microscopy has revealed that free cells contact the cerebrospinal fluid via abundant cytoplasmic processes that cross the cell layers of the pia mater and of the arachnoid. Cells expressing the MHC class II antigen are also found in all layers of the meninges. They are particularly abundant in the layers immediately adjacent to the subarachnoid space, in the neighbourhood of dural vessels, along the spinal roots and in the dural funnels. In addition to the meninges, strong immunoreactivity for MHC class II antigen is observed in the dorsal root ganglia. The ultrastructural and immunohistochemical findings of this study suggest the existence of a well-developed system of immunological surveillance of the subarachnoid space and of the dorsal root ganglia.

  1. Time Dependence of the Electron and Positron Components of the Cosmic Radiation Measured by the PAMELA Experiment between July 2006 and December 2015.

    PubMed

    Adriani, O; Barbarino, G C; Bazilevskaya, G A; Bellotti, R; Boezio, M; Bogomolov, E A; Bongi, M; Bonvicini, V; Bottai, S; Bruno, A; Cafagna, F; Campana, D; Carlson, P; Casolino, M; Castellini, G; De Santis, C; Di Felice, V; Galper, A M; Karelin, A V; Koldashov, S V; Koldobskiy, S A; Krutkov, S Y; Kvashnin, A N; Leonov, A; Malakhov, V; Marcelli, L; Martucci, M; Mayorov, A G; Menn, W; Mergé, M; Mikhailov, V V; Mocchiutti, E; Monaco, A; Mori, N; Munini, R; Osteria, G; Panico, B; Papini, P; Pearce, M; Picozza, P; Ricci, M; Ricciarini, S B; Simon, M; Sparvoli, R; Spillantini, P; Stozhkov, Y I; Vacchi, A; Vannuccini, E; Vasilyev, G I; Voronov, S A; Yurkin, Y T; Zampa, G; Zampa, N; Potgieter, M S; Vos, E E

    2016-06-17

    Cosmic-ray electrons and positrons are a unique probe of the propagation of cosmic rays as well as of the nature and distribution of particle sources in our Galaxy. Recent measurements of these particles are challenging our basic understanding of the mechanisms of production, acceleration, and propagation of cosmic rays. Particularly striking are the differences between the low energy results collected by the space-borne PAMELA and AMS-02 experiments and older measurements pointing to sign-charge dependence of the solar modulation of cosmic-ray spectra. The PAMELA experiment has been measuring the time variation of the positron and electron intensity at Earth from July 2006 to December 2015 covering the period for the minimum of solar cycle 23 (2006-2009) until the middle of the maximum of solar cycle 24, through the polarity reversal of the heliospheric magnetic field which took place between 2013 and 2014. The positron to electron ratio measured in this time period clearly shows a sign-charge dependence of the solar modulation introduced by particle drifts. These results provide the first clear and continuous observation of how drift effects on solar modulation have unfolded with time from solar minimum to solar maximum and their dependence on the particle rigidity and the cyclic polarity of the solar magnetic field.

  2. Measurement of the high energy component of the x-ray spectra in the VENUS electron cyclotron resonance ion source (abstract only)

    SciTech Connect

    Leitner, D.; Benitez, J. Y.; Lyneis, C. M.; Todd, D. S.; Ropponen, T.; Ropponen, J.; Koivisto, H.; Gammino, S.

    2008-02-15

    High performance electron cyclotron resonance (ECR) ion sources, such as VENUS (versatile ECR for nuclear science), produce large amounts of x rays. By studying their energy spectra, conclusions can be drawn about the electron heating process and the electron confinement. In addition, the bremsstrahlung from the plasma chamber is partly absorbed by the cold mass of the superconducting magnet adding an extra heat load to the cryostat. Germanium or NaI detectors are generally used for x-ray measurements. Due to the high x-ray flux from the source, the experimental setup to measure bremsstrahlung spectra from ECR ion sources is somewhat different than for the traditional nuclear physics measurements these detectors are generally used for. In particular, the collimation and background shielding can be problematic. In this paper we will discuss the experimental setup for such a measurement, the energy calibration and background reduction, the shielding of the detector, and collimation of the x-ray flux. We will present x-ray energy spectra and cryostat heating rates in dependence of various ion source parameters such as confinement fields, minimum B-field, rf power, and heating frequency.

  3. Time Dependence of the Electron and Positron Components of the Cosmic Radiation Measured by the PAMELA Experiment between July 2006 and December 2015

    NASA Astrophysics Data System (ADS)

    Adriani, O.; Barbarino, G. C.; Bazilevskaya, G. A.; Bellotti, R.; Boezio, M.; Bogomolov, E. A.; Bongi, M.; Bonvicini, V.; Bottai, S.; Bruno, A.; Cafagna, F.; Campana, D.; Carlson, P.; Casolino, M.; Castellini, G.; De Santis, C.; Di Felice, V.; Galper, A. M.; Karelin, A. V.; Koldashov, S. V.; Koldobskiy, S. A.; Krutkov, S. Y.; Kvashnin, A. N.; Leonov, A.; Malakhov, V.; Marcelli, L.; Martucci, M.; Mayorov, A. G.; Menn, W.; Mergé, M.; Mikhailov, V. V.; Mocchiutti, E.; Monaco, A.; Mori, N.; Munini, R.; Osteria, G.; Panico, B.; Papini, P.; Pearce, M.; Picozza, P.; Ricci, M.; Ricciarini, S. B.; Simon, M.; Sparvoli, R.; Spillantini, P.; Stozhkov, Y. I.; Vacchi, A.; Vannuccini, E.; Vasilyev, G. I.; Voronov, S. A.; Yurkin, Y. T.; Zampa, G.; Zampa, N.; Potgieter, M. S.; Vos, E. E.

    2016-06-01

    Cosmic-ray electrons and positrons are a unique probe of the propagation of cosmic rays as well as of the nature and distribution of particle sources in our Galaxy. Recent measurements of these particles are challenging our basic understanding of the mechanisms of production, acceleration, and propagation of cosmic rays. Particularly striking are the differences between the low energy results collected by the space-borne PAMELA and AMS-02 experiments and older measurements pointing to sign-charge dependence of the solar modulation of cosmic-ray spectra. The PAMELA experiment has been measuring the time variation of the positron and electron intensity at Earth from July 2006 to December 2015 covering the period for the minimum of solar cycle 23 (2006-2009) until the middle of the maximum of solar cycle 24, through the polarity reversal of the heliospheric magnetic field which took place between 2013 and 2014. The positron to electron ratio measured in this time period clearly shows a sign-charge dependence of the solar modulation introduced by particle drifts. These results provide the first clear and continuous observation of how drift effects on solar modulation have unfolded with time from solar minimum to solar maximum and their dependence on the particle rigidity and the cyclic polarity of the solar magnetic field.

  4. Time Dependence of the Electron and Positron Components of the Cosmic Radiation Measured by the PAMELA Experiment between July 2006 and December 2015.

    PubMed

    Adriani, O; Barbarino, G C; Bazilevskaya, G A; Bellotti, R; Boezio, M; Bogomolov, E A; Bongi, M; Bonvicini, V; Bottai, S; Bruno, A; Cafagna, F; Campana, D; Carlson, P; Casolino, M; Castellini, G; De Santis, C; Di Felice, V; Galper, A M; Karelin, A V; Koldashov, S V; Koldobskiy, S A; Krutkov, S Y; Kvashnin, A N; Leonov, A; Malakhov, V; Marcelli, L; Martucci, M; Mayorov, A G; Menn, W; Mergé, M; Mikhailov, V V; Mocchiutti, E; Monaco, A; Mori, N; Munini, R; Osteria, G; Panico, B; Papini, P; Pearce, M; Picozza, P; Ricci, M; Ricciarini, S B; Simon, M; Sparvoli, R; Spillantini, P; Stozhkov, Y I; Vacchi, A; Vannuccini, E; Vasilyev, G I; Voronov, S A; Yurkin, Y T; Zampa, G; Zampa, N; Potgieter, M S; Vos, E E

    2016-06-17

    Cosmic-ray electrons and positrons are a unique probe of the propagation of cosmic rays as well as of the nature and distribution of particle sources in our Galaxy. Recent measurements of these particles are challenging our basic understanding of the mechanisms of production, acceleration, and propagation of cosmic rays. Particularly striking are the differences between the low energy results collected by the space-borne PAMELA and AMS-02 experiments and older measurements pointing to sign-charge dependence of the solar modulation of cosmic-ray spectra. The PAMELA experiment has been measuring the time variation of the positron and electron intensity at Earth from July 2006 to December 2015 covering the period for the minimum of solar cycle 23 (2006-2009) until the middle of the maximum of solar cycle 24, through the polarity reversal of the heliospheric magnetic field which took place between 2013 and 2014. The positron to electron ratio measured in this time period clearly shows a sign-charge dependence of the solar modulation introduced by particle drifts. These results provide the first clear and continuous observation of how drift effects on solar modulation have unfolded with time from solar minimum to solar maximum and their dependence on the particle rigidity and the cyclic polarity of the solar magnetic field. PMID:27367381

  5. Mineral chemistry of lunar samples.

    PubMed

    Keil, K; Prinz, M; Bunch, T E

    1970-01-30

    Glass spherules, glass fragments, augite, ferroaugite, titanaugite, pyroxmangite, pigeonite, hypersthene, plagioclase, potassium feldspar, maskelynite, olivine, silica, ilmenite, TiO(2), "ferropseudobrookite," spinel, ulvöspinel, native iron, nickel-iron, troilite, and chlorapatite were analyzed with the electron microprobe. There are no indications of large-scale chemical differentiation, chemical weathering, or hydrous minerals. Contributions of meteoritic material to lunar surface rocks are small. Rocks with igneous textures originated from a melt that crystallized at or near the surface, and oxygen fugacities have been low. Shock features indicate that at least some surface material is impact-produced.

  6. Skeletal biology: Where matrix meets mineral.

    PubMed

    Young, Marian F

    2016-01-01

    The skeleton is unique from all other tissues in the body because of its ability to mineralize. The incorporation of mineral into bones and teeth is essential to give them strength and structure for body support and function. For years, researchers have wondered how mineralized tissues form and repair. A major focus in this context has been on the role of the extracellular matrix, which harbors key regulators of the mineralization process. In this introductory minireview, we will review some key concepts of matrix biology as it related to mineralized tissues. Concurrently, we will highlight the subject of this special issue covering many aspects of mineralized tissues, including bones and teeth and their associated structures cartilage and tendon. Areas of emphasis are on the generation and analysis of new animal models with permutations of matrix components as well as the development of new approaches for tissue engineering for repair of damaged hard tissue. In assembling key topics on mineralized tissues written by leaders in our field, we hope the reader will get a broad view of the topic and all of its fascinating complexities. PMID:27131884

  7. Magnetic Resonance Microscopy of Collagen Mineralization

    PubMed Central

    Chesnick, Ingrid E.; Mason, Jeffrey T.; Giuseppetti, Anthony A.; Eidelman, Naomi; Potter, Kimberlee

    2008-01-01

    A model mineralizing system was subjected to magnetic resonance microscopy to investigate how water proton transverse (T2) relaxation times and magnetization transfer ratios can be applied to monitor collagen mineralization. In our model system, a collagen sponge was mineralized with polymer-stabilized amorphous calcium carbonate. The lower hydration and water proton T2 values of collagen sponges during the initial mineralization phase were attributed to the replacement of the water within the collagen fibrils by amorphous calcium carbonate. The significant reduction in T2 values by day 6 (p < 0.001) was attributed to the appearance of mineral crystallites, which were also detected by x-ray diffraction and scanning electron microscopy. In the second phase, between days 6 and 13, magnetic resonance microscopy properties appear to plateau as amorphous calcium carbonate droplets began to coalesce within the intrafibrillar space of collagen. In the third phase, after day 15, the amorphous mineral phase crystallized, resulting in a reduction in the absolute intensity of the collagen diffraction pattern. We speculate that magnetization transfer ratio values for collagen sponges, with similar collagen contents, increased from 0.25 ± 0.02 for control strips to a maximum value of 0.31 ± 0.04 at day 15 (p = 0.03) because mineral crystals greatly reduce the mobility of the collagen fibrils. PMID:18487295

  8. Matrix Gla protein inhibition of tooth mineralization.

    PubMed

    Kaipatur, N R; Murshed, M; McKee, M D

    2008-09-01

    Extracellular matrix (ECM) mineralization is regulated by mineral ion availability, proteins, and other molecular determinants. To investigate protein regulation of mineralization in tooth dentin and cementum, and in alveolar bone, we expressed matrix Gla protein (MGP) ectopically in bones and teeth in mice, using an osteoblast/odontoblast-specific 2.3-kb Col1a1 promoter. Mandibles were analyzed by radiography, micro-computed tomography, light microscopy, histomorphometry, and transmission electron microscopy. While bone and tooth ECMs were established in the Col1a1-Mgp mice, extensive hypomineralization was observed, with values of unmineralized ECM from four- to eight-fold higher in dentin and alveolar bone when compared with that in wild-type tissues. Mineralization was virtually absent in tooth root dentin and cellular cementum, while crown dentin showed "breakthrough" areas of mineralization. Acellular cementum was lacking in Col1a1-Mgp teeth, and unmineralized osteodentin formed within the pulp. These results strengthen the view that bone and tooth mineralization is critically regulated by mineralization inhibitors. PMID:18719210

  9. Quantitative x ray microanalysis of pulmonary mineral particles in a patient with pneumoconiosis and two primary lung tumours.

    PubMed Central

    Anttila, S; Sutinen, S; Pääkkö, P; Alapieti, T; Peura, R; Sivonen, S J

    1984-01-01

    The right upper lung lobe of a 74 year old man was resected for a central tumour. Two primary cancers were found; a central small cell carcinoma and a peripheral squamous cell carcinoma. In addition, the peripheral lung tissue showed generalised peribronchiolar fibrosis extending from the non-respiratory bronchioles to the level of the alveolar ducts. Abundant asbestos bodies and large amounts of black dust were seen around the bronchioles. Pulmonary mineral particles were studied by quantitative energy dispersive x ray microanalysis (EDS) using scanning transmission electron microscopy (STEM). The x ray spectra for mineral particles were measured in thin sections, and the characteristic peak intensities of the elements were converted to weight fractions (in oxides). The results enabled the minerals present to be identified and their presence confirmed by calculating the mineral formula. These originated from nine natural minerals, anthophyllite and chrysotile asbestos, talc, and quartz, feldspars, and muscovite, which are components of sand, and also from two artificial mullites used in fire clay. The exposure history of the patient explained the most likely origins of the minerals detected. The patient had been a mason for 23 years, repairing and demolishing stoves and fireplaces and using asbestos for insulation work. Images PMID:6093848

  10. 36 CFR 293.14 - Mineral leases and mineral permits.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 2 2014-07-01 2014-07-01 false Mineral leases and mineral... AGRICULTURE WILDERNESS-PRIMITIVE AREAS § 293.14 Mineral leases and mineral permits. (a) All laws pertaining to mineral leasing shall extend to each National Forest Wilderness for the period specified in the...

  11. 36 CFR 293.14 - Mineral leases and mineral permits.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Mineral leases and mineral... AGRICULTURE WILDERNESS-PRIMITIVE AREAS § 293.14 Mineral leases and mineral permits. (a) All laws pertaining to mineral leasing shall extend to each National Forest Wilderness for the period specified in the...

  12. 36 CFR 293.14 - Mineral leases and mineral permits.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 2 2012-07-01 2012-07-01 false Mineral leases and mineral... AGRICULTURE WILDERNESS-PRIMITIVE AREAS § 293.14 Mineral leases and mineral permits. (a) All laws pertaining to mineral leasing shall extend to each National Forest Wilderness for the period specified in the...

  13. 36 CFR 293.14 - Mineral leases and mineral permits.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 2 2011-07-01 2011-07-01 false Mineral leases and mineral... AGRICULTURE WILDERNESS-PRIMITIVE AREAS § 293.14 Mineral leases and mineral permits. (a) All laws pertaining to mineral leasing shall extend to each National Forest Wilderness for the period specified in the...

  14. 36 CFR 293.14 - Mineral leases and mineral permits.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 2 2013-07-01 2013-07-01 false Mineral leases and mineral... AGRICULTURE WILDERNESS-PRIMITIVE AREAS § 293.14 Mineral leases and mineral permits. (a) All laws pertaining to mineral leasing shall extend to each National Forest Wilderness for the period specified in the...

  15. Digging into Minnesota Minerals.

    ERIC Educational Resources Information Center

    Minnesota State Dept. of Natural Resources, St. Paul.

    This publication presents students with facts about geology and several learning activities. Topics covered include rocks and minerals, volcanoes and earthquakes, fossils, exploration geology, mining in Minnesota, environmental issues related to mining, mineral uses, mining history, and the geology of Minnesota's state parks. A geologic timetable…

  16. Mineral Fiber Toxicology

    EPA Science Inventory

    The chemical and physical properties of different forms of mineral fibers impact biopersistence and pathology in the lung. Fiber chemistry, length, aspect ratio, surface area and dose are critical factors determining mineral fiber-associated health effects including cancer and as...

  17. Mineral Commodity Summaries 2001

    USGS Publications Warehouse

    ,

    2001-01-01

    Published on an annual basis, this report is the earliest Government publication to furnish estimates covering nonfuel mineral industry data. Data sheets contain information on the domestic industry structure, Government programs, tariffs, and 5-year salient statistics for over 90 individual minerals and materials.

  18. Mineral Commodity Summaries 2005

    USGS Publications Warehouse

    ,

    2005-01-01

    Published on an annual basis, this report is the earliest Government publication to furnish estimates covering nonfuel mineral industry data. Data sheets contain information on the domestic industry structure, Government programs, tariffs, and 5-year salient statistics for over 90 individual minerals and materials.

  19. Mineral Commodity Summaries 2004

    USGS Publications Warehouse

    ,

    2004-01-01

    Published on an annual basis, this report is the earliest Government publication to furnish estimates covering nonfuel mineral industry data. Data sheets contain information on the domestic industry structure, Government programs, tariffs, and 5-year salient statistics for over 90 individual minerals and materials.

  20. Mineral Commodity Summaries 2000

    USGS Publications Warehouse

    ,

    2000-01-01

    Published on an annual basis, this report is the earliest Government publication to furnish estimates covering nonfuel mineral industry data. Data sheets contain information on the domestic industry structure, Government programs, tariffs, and 5-year salient statistics for over 90 individual minerals and materials.

  1. Mineral Commodity Summaries 2006

    USGS Publications Warehouse

    ,

    2006-01-01

    Published on an annual basis, this report is the earliest Government publication to furnish estimates covering nonfuel mineral industry data. Data sheets contain information on the domestic industry structure, Government programs, tariffs, and 5-year salient statistics for over 90 individual minerals and materials.

  2. Mineral Commodity Summaries 2003

    USGS Publications Warehouse

    ,

    2003-01-01

    Published on an annual basis, this report is the earliest Government publication to furnish estimates covering nonfuel mineral industry data. Data sheets contain information on the domestic industry structure, Government programs, tariffs, and 5-year salient statistics for over 90 individual minerals and materials.

  3. Mineral Commodity Summaries 1999

    USGS Publications Warehouse

    ,

    1999-01-01

    Published on an annual basis, this report is the earliest Government publication to furnish estimates covering nonfuel mineral industry data. Data sheets contain information on the domestic industry structure, Government programs, tariffs, and 5-year salient statistics for over 90 individual minerals and materials.

  4. Mineral Commodity Summaries 2007

    USGS Publications Warehouse

    ,

    2007-01-01

    Published on an annual basis, this report is the earliest Government publication to furnish estimates covering nonfuel mineral industry data. Data sheets contain information on the domestic industry structure, Government programs, tariffs, and 5-year salient statistics for over 90 individual minerals and materials.

  5. Mineral Commodity Summaries 1998

    USGS Publications Warehouse

    ,

    1998-01-01

    Published on an annual basis, this report is the earliest Government publication to furnish estimates covering nonfuel mineral industry data. Data sheets contain information on the domestic industry structure, Government programs, tariffs, and 5-year salient statistics for over 90 individual minerals and materials.

  6. Mineral Commodity Summaries 1997

    USGS Publications Warehouse

    ,

    1997-01-01

    Published on an annual basis, this report is the earliest Government publication to furnish estimates covering nonfuel mineral industry data. Data sheets contain information on the domestic industry structure, Government programs, tariffs, and 5-year salient statistics for over 90 individual minerals and materials

  7. Mineral Commodity Summaries 2002

    USGS Publications Warehouse

    ,

    2002-01-01

    Published on an annual basis, this report is the earliest Government publication to furnish estimates covering nonfuel mineral industry data. Data sheets contain information on the domestic industry structure, Government programs, tariffs, and 5-year salient statistics for over 90 individual minerals and materials.

  8. The Miner's Canary

    ERIC Educational Resources Information Center

    Guinier, Lani

    2005-01-01

    Miners used canaries as early warning signals: when a canary gasped for breath, the miners knew there was a problem with the atmosphere in the mine. The experience of people of color in higher education can be used similarly as a diagnostic tool.

  9. Vitamins, Minerals, and Mood

    ERIC Educational Resources Information Center

    Kaplan, Bonnie J.; Crawford, Susan G.; Field, Catherine J.; Simpson, J. Steven A.

    2007-01-01

    In this article, the authors explore the breadth and depth of published research linking dietary vitamins and minerals (micronutrients) to mood. Since the 1920s, there have been many studies on individual vitamins (especially B vitamins and Vitamins C, D, and E), minerals (calcium, chromium, iron, magnesium, zinc, and selenium), and vitamin-like…

  10. Mineral commodity summaries 2016

    USGS Publications Warehouse

    Ober, Joyce A.

    2016-01-01

    This report is the earliest Government publication to furnish estimates covering 2015 nonfuel mineral industry data. Data sheets contain information on the domestic industry structure, Government programs, tariffs, and 5-year salient statistics for more than 90 individual minerals and materials

  11. Rational engineering of Geobacter sulfurreducens electron transfer components: A foundation for building improved Geobacter-based bioelectrochemical technologies

    SciTech Connect

    Dantas, Joana M.; Morgado, Leonor; Aklujkar, Muktak; Bruix, Marta; Londer, Yuri Y.; Schiffer, Marianne; Pokkuluri, P. Raj; Salgueiro, Carlos A.

    2015-07-30

    Multiheme cytochromes have been implicated in Geobacter sulfurreducens extracellular electron transfer (EET). These proteins are potential targets to improve EET and enhance bioremediation and electrical current production by G. sulfurreducens. However, the functional characterization of multiheme cytochromes is particularly complex due to the co-existence of several microstates in solution, connecting the fully reduced and fully oxidized states. Throughout the last decade, new strategies have been developed to characterize multiheme redox proteins functionally and structurally. These strategies were used to reveal the functional mechanism of G. sulfurreducens multiheme cytochromes and also to identify key residues in these proteins for EET. In previous studies, we set the foundations for enhancement of the EET abilities of G. sulfurreducens by characterizing a family of five triheme cytochromes (PpcA-E). These periplasmic cytochromes are implicated in electron transfer between the oxidative reactions of metabolism in the cytoplasm and the reduction of extracellular terminal electron acceptors at the cell's outer surface. The results obtained suggested that PpcA can couple e-/H+ transfer, a property that might contribute to the proton electrochemical gradient across the cytoplasmic membrane for metabolic energy production. The structural and functional properties of PpcA were characterized in detail and used for rational design of a family of 23 single site PpcA mutants. In this review, we summarize the functional characterization of the native and mutant proteins. Mutants that retain the mechanistic features of PpcA and adopt preferential e-/H+ transfer pathways at lower reduction potential values compared to the wild-type protein were selected for in vivo studies as the best candidates to increase the electron transfer rate of G. sulfurreducens. For the first time G. sulfurreducens

  12. Electronic states and molecular dynamics of single-component molecular conductors [M (tmdt) 2] (M =Ni , Pt) studied by 13C and 1H NMR

    NASA Astrophysics Data System (ADS)

    Takagi, Rina; Miyagawa, Kazuya; Yoshimura, Masahide; Gangi, Hiro; Kanoda, Kazushi; Zhou, Biao; Idobata, Yuki; Kobayashi, Akiko

    2016-01-01

    The molecular conductors [M(tmdt) 2] (M =Ni , Pt) consisting of single molecular species are investigated with 13C NMR and 1H NMR. The temperature dependences of the 13C NMR shift and relaxation rate provide microscopic evidence for the metallic nature with appreciable electron correlations. Both compounds exhibit an anomalous frequency-dependent enhancement in the 1H nuclear spin-lattice relaxation rate in a wide temperature range. These observations signify the presence of extraordinary molecular motions with low energy excitations.

  13. Nanowires, Capacitors, and Other Novel Outer-Surface Components Involved in Electron Transfer to Fe(III) Oxides in Geobacter Species

    SciTech Connect

    Lovley, Derek R.

    2005-06-01

    In the past year studies have primarily focused on elucidating the role of pili in electron transport to Fe(III) oxide in Geobacter sulfurreducens. As summarized in last year's report, it was previously found that pili are specifically expressed during growth on Fe(III) oxide and that Fe(III) oxide reduction is inhibited if the gene for the structural pilin protein is deleted. However, it was also found that a pilin-deficient mutant of G. sulfurreducens could attached to Fe(III) oxide as well as wild type.

  14. Factors affecting ex-situ aqueous mineral carbonation using calcium and magnesium silicate minerals

    SciTech Connect

    Gerdemann, Stephen J.; Dahlin, David C.; O'Connor, William K.; Penner, Larry R.; Rush, G.E.

    2004-01-01

    Carbonation of magnesium- and calcium-silicate minerals to form their respective carbonates is one method to sequester carbon dioxide. Process development studies have identified reactor design as a key component affecting both the capital and operating costs of ex-situ mineral sequestration. Results from mineral carbonation studies conducted in a batch autoclave were utilized to design and construct a unique continuous pipe reactor with 100% recycle (flow-loop reactor). Results from the flow-loop reactor are consistent with batch autoclave tests, and are being used to derive engineering data necessary to design a bench-scale continuous pipeline reactor.

  15. Compounded PHOSPHO1/ALPL deficiencies reduce dentin mineralization.

    PubMed

    McKee, M D; Yadav, M C; Foster, B L; Somerman, M J; Farquharson, C; Millán, J L

    2013-08-01

    Phosphatases are involved in bone and tooth mineralization, but their mechanisms of action are not completely understood. Tissue-nonspecific alkaline phosphatase (TNAP, ALPL) regulates inhibitory extracellular pyrophosphate through its pyrophosphatase activity to control mineral propagation in the matrix; mice without TNAP lack acellular cementum, and have mineralization defects in dentin, enamel, and bone. PHOSPHO1 is a phosphatase found within membrane-bounded matrix vesicles in mineralized tissues, and double ablation of Alpl and Phospho1 in mice leads to a complete absence of skeletal mineralization. Here, we describe mineralization abnormalities in the teeth of Phospho1(-/-) mice, and in compound knockout mice lacking Phospho1 and one allele of Alpl (Phospho1(-/-);Alpl(+/-) ). In wild-type mice, PHOSPHO1 and TNAP co-localized to odontoblasts at early stages of dentinogenesis, coincident with the early mineralization of mantle dentin. In Phospho1 knockout mice, radiography, micro-computed tomography, histology, and transmission electron microscopy all demonstrated mineralization abnormalities of incisor dentin, with the most remarkable findings being reduced overall mineralization coincident with decreased matrix vesicle mineralization in the Phospho1(-/-) mice, and the almost complete absence of matrix vesicles in the Phospho1(-/-);Alpl(+/-) mice, whose incisors showed a further reduction in mineralization. Results from this study support prominent non-redundant roles for both PHOSPHO1 and TNAP in dentin mineralization.

  16. Underground mineral extraction

    NASA Technical Reports Server (NTRS)

    Miller, C. G.; Stephens, J. B.

    1980-01-01

    A method was developed for extracting underground minerals such as coal, which avoids the need for sending personnel underground and which enables the mining of steeply pitched seams of the mineral. The method includes the use of a narrow vehicle which moves underground along the mineral seam and which is connected by pipes or hoses to water pumps at the surface of the Earth. The vehicle hydraulically drills pilot holes during its entrances into the seam, and then directs sideward jets at the seam during its withdrawal from each pilot hole to comminute the mineral surrounding the pilot hole and combine it with water into a slurry, so that the slurried mineral can flow to a location where a pump raises the slurry to the surface.

  17. Mineral resource of the month: phosphate rock

    USGS Publications Warehouse

    Jasinski, Stephen M.

    2007-01-01

    Phosphate rock minerals provide the only significant global resources of phosphorus, which is an essential element for plant and animal nutrition. Phosphate rock is used primarily as a principal component of nitrogen-phosphorus-potassium fertilizers, but also to produce elemental phosphorus and animal feed.

  18. Mineral resource of the month: lithium

    USGS Publications Warehouse

    Ober, Joyce A.

    2006-01-01

    Lithium, the lightest metallic element, is silvery, white and soft, and highly reactive. It is used most frequently in chemical compounds or traded as mineral concentrates. Its thermal properties make it an ideal component in thermal shock-resistant ceramics, and its electrochemical properties make it an ideal material for several types of batteries.

  19. Mineral resource of the month: diatomite

    USGS Publications Warehouse

    ,

    2013-01-01

    The article discusses the properties and applications of the mineral diatomite. According to the author, diatomite is a soft, friable and very fine-grained siliceous sedimentary rock made of the remains of fossilized diatoms. The author adds that its properties make diatomite very useful as a filtration medium and as a component in cement.

  20. Desert varnish: the importance of clay minerals.

    PubMed

    Potter, R M; Rossman, G R

    1977-06-24

    Desert varnish has been characterized by infrared spectroscopy, x-ray diffraction, and electron microscopy. It is a distinct morphological entity having an abrupt boundary with the underlying rock. Clay minerals comprise more than 70 percent of the varnish. Iron and manganese oxides constitute the bulk of the remainder and are dispersed throughout the clay layer. PMID:17776923