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  1. Physically and chemically stable ionic liquid-infused textured surfaces showing excellent dynamic omniphobicity

    Energy Technology Data Exchange (ETDEWEB)

    Miranda, Daniel F.; Urata, Chihiro; Masheder, Benjamin; Dunderdale, Gary J.; Hozumi, Atsushi, E-mail: a.hozumi@aist.go.jp [National Institute of Advanced Industrial Science and Technology (AIST), 2266-98, Anagahora, Shimo-Shidami, Moriyama-ku, Nagoya, Aichi 463-8560 (Japan); Yagihashi, Makoto [Nagoya Municipal Industrial Research Institute, Rokuban, Atsuta-ku, Nagoya 456-0058 (Japan)

    2014-05-01

    A fluorinated and hydrophobic ionic liquid (IL), 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide, effectively served as an advantageous lubricating liquid for the preparation of physically and chemically stable omniphobic surfaces based on slippery liquid-infused porous surfaces. Here, we used particulate microstructures as supports, prepared by the chemical vapor deposition of 1,3,5,7-tetramethylcyclotetrasiloxane and subsequent surface modification with (3-aminopropyl)triethoxysilane. Confirmed by SEM and contact angle measurements, the resulting IL-infused microtextured surfaces are smooth and not only water but also various low surface tension liquids can easily slide off at low substrate tilt angles of <5°, even after exposure to high temperature, vacuum, and UV irradiation.

  2. Physically and chemically stable ionic liquid-infused textured surfaces showing excellent dynamic omniphobicity

    Directory of Open Access Journals (Sweden)

    Daniel F. Miranda

    2014-05-01

    Full Text Available A fluorinated and hydrophobic ionic liquid (IL, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl imide, effectively served as an advantageous lubricating liquid for the preparation of physically and chemically stable omniphobic surfaces based on slippery liquid-infused porous surfaces. Here, we used particulate microstructures as supports, prepared by the chemical vapor deposition of 1,3,5,7-tetramethylcyclotetrasiloxane and subsequent surface modification with (3-aminopropyltriethoxysilane. Confirmed by SEM and contact angle measurements, the resulting IL-infused microtextured surfaces are smooth and not only water but also various low surface tension liquids can easily slide off at low substrate tilt angles of <5°, even after exposure to high temperature, vacuum, and UV irradiation.

  3. Are Vicinal Metal Surfaces Stable?

    DEFF Research Database (Denmark)

    Frenken, J. W. M.; Stoltze, Per

    1999-01-01

    We use effective medium theory to demonstrate that the energies of many metal surfaces are lowered when these surfaces are replaced by facets with lower-index orientations. This implies that the low-temperature equilibrium shapes of many metal crystals should be heavily faceted. The predicted...... instability of vicinal metal surfaces is at variance with the almost generally observed stability of these surfaces. We argue that the unstable orientations undergo a defaceting transition at relatively low temperatures, driven by the high vibrational entropy of steps....

  4. Exploring Scintillometry in the Stable Atmospheric Surface Layer

    NARCIS (Netherlands)

    Hartogensis, O.K.

    2006-01-01

    The main objective of this thesis is to investigate observation methods of heat and momentum exchange and key variables that characterise turbulence in the atmospheric stable surface layer (SSL), a layer defined as the lower part of the stable boundary layer (SBL) where surface fluxes do not change

  5. Structure of stable degeneration of K3 surfaces into pairs of rational elliptic surfaces

    OpenAIRE

    Kimura, Yusuke

    2018-01-01

    F-theory/heterotic duality is formulated in the stable degeneration limit of a K3 fibration on the F-theory side. In this note, we analyze the structure of the stable degeneration limit. We discuss whether stable degeneration exists for pairs of rational elliptic surfaces. We demonstrate that, when two rational elliptic surfaces have an identical complex structure, stable degeneration always exists. We provide an equation that systematically describes the stable degeneration of a K3 surface i...

  6. Graphene Films Show Stable Cell Attachment and Biocompatibility with Electrogenic Primary Cardiac Cells

    OpenAIRE

    Kim, Taeyong; Kahng, Yung Ho; Lee, Takhee; Lee, Kwanghee; Kim, Do Han

    2013-01-01

    Graphene has attracted substantial attention due to its advantageous materialistic applicability. In the present study, we tested the biocompatibility of graphene films synthesized by chemical vapor deposition with electrogenic primary adult cardiac cells (cardiomyocytes) by measuring the cell properties such as cell attachment, survival, contractility and calcium transients. The results show that the graphene films showed stable cell attachment and excellent biocompatibility with the electro...

  7. Long-term stable surface modification of DLC coatings

    Directory of Open Access Journals (Sweden)

    Gotzmann Gaby

    2017-09-01

    Full Text Available The use of coatings based on diamond like carbon (DLC for medical applications was established during the last years. Main advantages of these coatings are its high hardness, good wear and friction behavior and its biocompatibility. Using low-energy electron-beam treatment, we addressed the surface modification of DLC coatings. The aim was to generate new biofunctional surface characteristics that are long-term stable.

  8. Macromolecular surface design: photopatterning of functional stable nitrile oxides.

    Science.gov (United States)

    Altintas, Ozcan; Glassner, Mathias; Rodriguez-Emmenegger, Cesar; Welle, Alexander; Trouillet, Vanessa; Barner-Kowollik, Christopher

    2015-05-04

    The efficient trapping of photogenerated thioaldehydes with functional shelf-stable nitrile oxides in a 1,3-dipolar cycloaddition is a novel and versatile photochemical strategy for polymer end-group functionalization and surface modification under mild and equimolar conditions. The modular ligation in solution was followed in detail by electrospray ionization mass spectrometry (ESI-MS). X-ray photoelectron spectroscopy (XPS) was employed to analyze the functionalized surfaces, whereas time-of-flight secondary-ion mass spectrometry (ToF-SIMS) confirmed the spatial control of the surface functionalization using a micropatterned shadow mask. Polymer brushes were grown from the surface in a spatially confined regime by surface-initiated atom transfer radical polymerization (SI-ATRP) as confirmed by TOF-SIMS, XPS as well as ellipsometry. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. X-ray sensitive strains of CHO cells show decreased frequency of stable transfection

    International Nuclear Information System (INIS)

    Jeggo, P.; Smith, J.

    1987-01-01

    Six X-ray sensitive (xrs) strains of the Chinese hamster ovary cell line have previously been isolated and shown to have a defect in double strand break rejoining. In this study, these strains have been investigated for their ability to take up and integrate foreign DNA. All the xrs strains investigated so far have shown a decreased frequency of stable transfectants compared to their parent line, in experiments using the plasmid pSV2gpt, which contains the selectable bacterial gene, guanine phosphoribosyl transferase. This decreased frequency is observed over a wide range of DNA concentrations (0.1 to 20 μg DNA) but is more pronounced at higher DNA concentrations. In contrast, these xrs strains show the same level of transfection proficiency as the wild type parent using a transient transfection system with a plasmid containing the bacterial CAT (chloramphenicol acetyl transferase) gene. Since the level of CAT activity does not depend on integration of foreign DNA, this suggests that the xrs strains are able to take up the same amount of DNA as the parent strains, but have a defect in the integration of foreign DNA. Since this integration of foreign DNA probably occurs by non-homologous recombination, this may indicate a role of the xrs gene product in this process

  10. Structure of stable degeneration of K3 surfaces into pairs of rational elliptic surfaces

    Science.gov (United States)

    Kimura, Yusuke

    2018-03-01

    F-theory/heterotic duality is formulated in the stable degeneration limit of a K3 fibration on the F-theory side. In this note, we analyze the structure of the stable degeneration limit. We discuss whether stable degeneration exists for pairs of rational elliptic surfaces. We demonstrate that, when two rational elliptic surfaces have an identical complex structure, stable degeneration always exists. We provide an equation that systematically describes the stable degeneration of a K3 surface into a pair of isomorphic rational elliptic surfaces. When two rational elliptic surfaces have different complex structures, whether their sum glued along a smooth fiber admits deformation to a K3 surface can be determined by studying the structure of the K3 lattice. We investigate the lattice theoretic condition to determine whether a deformation to a K3 surface exists for pairs of extremal rational elliptic surfaces. In addition, we discuss the configurations of singular fibers under stable degeneration. The sum of two isomorphic rational elliptic surfaces glued together admits a deformation to a K3 surface, the singular fibers of which are twice that of the rational elliptic surface. For special situations, singular fibers of the resulting K3 surface collide and they are enhanced to a fiber of another type. Some K3 surfaces become attractive in these situations. We determine the complex structures and the Weierstrass forms of these attractive K3 surfaces. We also deduce the gauge groups in F-theory compactifications on these attractive K3 surfaces times a K3. E 6, E 7, E 8, SU(5), and SO(10) gauge groups arise in these compactifications.

  11. Is bicarbonate stable in and on the calcite surface?

    Science.gov (United States)

    Andersson, M. P.; Rodriguez-Blanco, J. D.; Stipp, S. L. S.

    2016-03-01

    We have used density functional theory with the COSMO-RS implicit solvent model to predict the pKa for the deprotonation of bicarbonate to carbonate, i.e. HCO3- CO32- + H+, when HCO3- is included in, and adsorbed on, a calcite surface. We have used cluster models (80-100 atoms) to represent the flat {10.4} surface, acute steps, obtuse steps, two types of kinks on the acute step and two types of kinks on the obtuse steps. Based on the predicted pKa values, which range from -6.0 to 2.4 depending on the surface site, we conclude that bicarbonate deprotonates to carbonate when it is in calcite even when pH in solution is very low. This is true for all surface sites, even for solutions where 2.4 < pH < 6.35, where H2CO30 is the dominant dissolved species. When bicarbonate is adsorbed on calcite, the predicted pKa for deprotonation is 7.5, which is ∼3 pH units lower than in aqueous solution, 10.35. This means that adsorbed carbonate is stable even when the concentration of dissolved CO32- is several orders of magnitude lower. This has a significant effect on surface charge and thus the behaviour of the calcite surface. Our results help explain the potential determining behaviour of the carbonate species in calcite-water systems, particularly in the pH range where the bicarbonate species dominates in water and where the carbonate species dominates at the surface, i.e. when 7.5 < pH < 10.35. Our atomic scale data for the various calcite surface sites provide the needed input to improve and constrain surface complexation modelling and are especially useful for predicting behaviour in systems where experiments are difficult or impossible, such as at high temperature and pressure.

  12. Surface engineered porous silicon for stable, high performance electrochemical supercapacitors

    Science.gov (United States)

    Oakes, Landon; Westover, Andrew; Mares, Jeremy W.; Chatterjee, Shahana; Erwin, William R.; Bardhan, Rizia; Weiss, Sharon M.; Pint, Cary L.

    2013-10-01

    Silicon materials remain unused for supercapacitors due to extreme reactivity of silicon with electrolytes. However, doped silicon materials boast a low mass density, excellent conductivity, a controllably etched nanoporous structure, and combined earth abundance and technological presence appealing to diverse energy storage frameworks. Here, we demonstrate a universal route to transform porous silicon (P-Si) into stable electrodes for electrochemical devices through growth of an ultra-thin, conformal graphene coating on the P-Si surface. This graphene coating simultaneously passivates surface charge traps and provides an ideal electrode-electrolyte electrochemical interface. This leads to 10-40X improvement in energy density, and a 2X wider electrochemical window compared to identically-structured unpassivated P-Si. This work demonstrates a technique generalizable to mesoporous and nanoporous materials that decouples the engineering of electrode structure and electrochemical surface stability to engineer performance in electrochemical environments. Specifically, we demonstrate P-Si as a promising new platform for grid-scale and integrated electrochemical energy storage.

  13. Surface engineered porous silicon for stable, high performance electrochemical supercapacitors

    Science.gov (United States)

    Oakes, Landon; Westover, Andrew; Mares, Jeremy W.; Chatterjee, Shahana; Erwin, William R.; Bardhan, Rizia; Weiss, Sharon M.; Pint, Cary L.

    2013-01-01

    Silicon materials remain unused for supercapacitors due to extreme reactivity of silicon with electrolytes. However, doped silicon materials boast a low mass density, excellent conductivity, a controllably etched nanoporous structure, and combined earth abundance and technological presence appealing to diverse energy storage frameworks. Here, we demonstrate a universal route to transform porous silicon (P-Si) into stable electrodes for electrochemical devices through growth of an ultra-thin, conformal graphene coating on the P-Si surface. This graphene coating simultaneously passivates surface charge traps and provides an ideal electrode-electrolyte electrochemical interface. This leads to 10–40X improvement in energy density, and a 2X wider electrochemical window compared to identically-structured unpassivated P-Si. This work demonstrates a technique generalizable to mesoporous and nanoporous materials that decouples the engineering of electrode structure and electrochemical surface stability to engineer performance in electrochemical environments. Specifically, we demonstrate P-Si as a promising new platform for grid-scale and integrated electrochemical energy storage. PMID:24145684

  14. Mitotic evolution of Plasmodium falciparum shows a stable core genome but recombination in antigen families.

    Directory of Open Access Journals (Sweden)

    Selina E R Bopp

    Full Text Available Malaria parasites elude eradication attempts both within the human host and across nations. At the individual level, parasites evade the host immune responses through antigenic variation. At the global level, parasites escape drug pressure through single nucleotide variants and gene copy amplification events conferring drug resistance. Despite their importance to global health, the rates at which these genomic alterations emerge have not been determined. We studied the complete genomes of different Plasmodium falciparum clones that had been propagated asexually over one year in the presence and absence of drug pressure. A combination of whole-genome microarray analysis and next-generation deep resequencing (totaling 14 terabases revealed a stable core genome with only 38 novel single nucleotide variants appearing in seventeen evolved clones (avg. 5.4 per clone. In clones exposed to atovaquone, we found cytochrome b mutations as well as an amplification event encompassing the P. falciparum multidrug resistance associated protein (mrp1 on chromosome 1. We observed 18 large-scale (>1 kb on average deletions of telomere-proximal regions encoding multigene families, involved in immune evasion (9.5×10(-6 structural variants per base pair per generation. Six of these deletions were associated with chromosomal crossovers generated during mitosis. We found only minor differences in rates between genetically distinct strains and between parasites cultured in the presence or absence of drug. Using these derived mutation rates for P. falciparum (1.0-9.7×10(-9 mutations per base pair per generation, we can now model the frequency at which drug or immune resistance alleles will emerge under a well-defined set of assumptions. Further, the detection of mitotic recombination events in var gene families illustrates how multigene families can arise and change over time in P. falciparum. These results will help improve our understanding of how P. falciparum

  15. Mitotic Evolution of Plasmodium falciparum Shows a Stable Core Genome but Recombination in Antigen Families

    Science.gov (United States)

    Bopp, Selina E. R.; Manary, Micah J.; Bright, A. Taylor; Johnston, Geoffrey L.; Dharia, Neekesh V.; Luna, Fabio L.; McCormack, Susan; Plouffe, David; McNamara, Case W.; Walker, John R.; Fidock, David A.; Denchi, Eros Lazzerini; Winzeler, Elizabeth A.

    2013-01-01

    Malaria parasites elude eradication attempts both within the human host and across nations. At the individual level, parasites evade the host immune responses through antigenic variation. At the global level, parasites escape drug pressure through single nucleotide variants and gene copy amplification events conferring drug resistance. Despite their importance to global health, the rates at which these genomic alterations emerge have not been determined. We studied the complete genomes of different Plasmodium falciparum clones that had been propagated asexually over one year in the presence and absence of drug pressure. A combination of whole-genome microarray analysis and next-generation deep resequencing (totaling 14 terabases) revealed a stable core genome with only 38 novel single nucleotide variants appearing in seventeen evolved clones (avg. 5.4 per clone). In clones exposed to atovaquone, we found cytochrome b mutations as well as an amplification event encompassing the P. falciparum multidrug resistance associated protein (mrp1) on chromosome 1. We observed 18 large-scale (>1 kb on average) deletions of telomere-proximal regions encoding multigene families, involved in immune evasion (9.5×10−6 structural variants per base pair per generation). Six of these deletions were associated with chromosomal crossovers generated during mitosis. We found only minor differences in rates between genetically distinct strains and between parasites cultured in the presence or absence of drug. Using these derived mutation rates for P. falciparum (1.0–9.7×10−9 mutations per base pair per generation), we can now model the frequency at which drug or immune resistance alleles will emerge under a well-defined set of assumptions. Further, the detection of mitotic recombination events in var gene families illustrates how multigene families can arise and change over time in P. falciparum. These results will help improve our understanding of how P. falciparum evolves to

  16. Stable water isotope and surface heat flux simulation using ISOLSM: Evaluation against in-situ measurements

    KAUST Repository

    Cai, Mick Y.; Wang, Lixin; Parkes, Stephen; Strauss, Josiah; McCabe, Matthew; Evans, Jason P.; Griffiths, Alan D.

    2015-01-01

    The stable isotopes of water are useful tracers of water sources and hydrological processes. Stable water isotope-enabled land surface modeling is a relatively new approach for characterizing the hydrological cycle, providing spatial and temporal variability for a number of hydrological processes. At the land surface, the integration of stable water isotopes with other meteorological measurements can assist in constraining surface heat flux estimates and discriminate between evaporation (E) and transpiration (T). However, research in this area has traditionally been limited by a lack of continuous in-situ isotopic observations. Here, the National Centre for Atmospheric Research stable isotope-enabled Land Surface Model (ISOLSM) is used to simulate the water and energy fluxes and stable water isotope variations. The model was run for a period of one month with meteorological data collected from a coastal sub-tropical site near Sydney, Australia. The modeled energy fluxes (latent heat and sensible heat) agreed reasonably well with eddy covariance observations, indicating that ISOLSM has the capacity to reproduce observed flux behavior. Comparison of modeled isotopic compositions of evapotranspiration (ET) against in-situ Fourier Transform Infrared spectroscopy (FTIR) measured bulk water vapor isotopic data (10. m above the ground), however, showed differences in magnitude and temporal patterns. The disparity is due to a small contribution from local ET fluxes to atmospheric boundary layer water vapor (~1% based on calculations using ideal gas law) relative to that advected from the ocean for this particular site. Using ISOLSM simulation, the ET was partitioned into E and T with 70% being T. We also identified that soil water from different soil layers affected T and E differently based on the simulated soil isotopic patterns, which reflects the internal working of ISOLSM. These results highlighted the capacity of using the isotope-enabled models to discriminate

  17. Stable water isotope and surface heat flux simulation using ISOLSM: Evaluation against in-situ measurements

    KAUST Repository

    Cai, Mick Y.

    2015-04-01

    The stable isotopes of water are useful tracers of water sources and hydrological processes. Stable water isotope-enabled land surface modeling is a relatively new approach for characterizing the hydrological cycle, providing spatial and temporal variability for a number of hydrological processes. At the land surface, the integration of stable water isotopes with other meteorological measurements can assist in constraining surface heat flux estimates and discriminate between evaporation (E) and transpiration (T). However, research in this area has traditionally been limited by a lack of continuous in-situ isotopic observations. Here, the National Centre for Atmospheric Research stable isotope-enabled Land Surface Model (ISOLSM) is used to simulate the water and energy fluxes and stable water isotope variations. The model was run for a period of one month with meteorological data collected from a coastal sub-tropical site near Sydney, Australia. The modeled energy fluxes (latent heat and sensible heat) agreed reasonably well with eddy covariance observations, indicating that ISOLSM has the capacity to reproduce observed flux behavior. Comparison of modeled isotopic compositions of evapotranspiration (ET) against in-situ Fourier Transform Infrared spectroscopy (FTIR) measured bulk water vapor isotopic data (10. m above the ground), however, showed differences in magnitude and temporal patterns. The disparity is due to a small contribution from local ET fluxes to atmospheric boundary layer water vapor (~1% based on calculations using ideal gas law) relative to that advected from the ocean for this particular site. Using ISOLSM simulation, the ET was partitioned into E and T with 70% being T. We also identified that soil water from different soil layers affected T and E differently based on the simulated soil isotopic patterns, which reflects the internal working of ISOLSM. These results highlighted the capacity of using the isotope-enabled models to discriminate

  18. Thermodynamics of Minerals Stable Near the Earth's Surface

    International Nuclear Information System (INIS)

    Navrotsky, Alexandra

    2003-01-01

    OAK B262 Research and Education Activities We are working on developing calorimetric techniques for sulfide minerals. We have completed calorimetric studies of (Na, K, H3O) jarosites, of Na and K jarosite -alunite solid solutions, and of Cr6+ - containing jarosites. We are now working on phases containing As and Pb. These studies are important to issues of heavy metal pollution in the environment. A number of postdocs, graduate students, and undergrads have participated in the research. We have active collaboration with Dirk Baron, faculty at California State University, Bakersfield. In a collaboration with Peter Burns, Notre Dame University, we are working on thermochemistry of U6+ minerals. Navrotsky has participated in a number of national workshops that are helping to define the interfaces between nanotechnology and earth/environmental science. Major Findings Our first finding on uranyl minerals shows that studtite, a phase containing structural peroxide ion, is thermodynamically unstable in the absence of a source of aqueous peroxide ion but is thermodynamically stable in contact with a solution containing peroxide concentrations expected for the radiolysis of water in contact with spent nuclear fuel. This work is in press in Science. We have a consistent thermodynamic data set for the (Na, K, H3O) (Al, Fe) jarosite, alunite minerals and for Cr6+ substituting for S6+ in jarosite. The latter phases represent one of the few solid sinks for trapping toxic Cr6+ in groundwater. Contributions within Discipline Better understanding of thermodynamic driving for and constraints on geochemical and environmental processes

  19. Fabrication and characterization of stable superhydrophobic surface with good friction-reducing performance on Al foil

    Energy Technology Data Exchange (ETDEWEB)

    Li, Peipei [Key Laboratory of Ministry of Education for Special Functional Materials, Henan University, Kaifeng 475004 (China); Chen, Xinhua, E-mail: xuc0374@hotmail.com [College of Chemistry and Chemical Engineering, Xuchang University, Xuchang 461000 (China); Yang, Guangbin; Yu, Laigui [Key Laboratory of Ministry of Education for Special Functional Materials, Henan University, Kaifeng 475004 (China); Zhang, Pingyu, E-mail: pingyu@henu.edu.cn [Key Laboratory of Ministry of Education for Special Functional Materials, Henan University, Kaifeng 475004 (China)

    2014-05-01

    Graphical abstract: A lotus-leaf-like hierarchical structure was successfully created on Al foil by a facile three-step solution–immersion method. As-obtained etched-immersed Al/STA rough surface contains interconnected convex–concave micro-structure and uniformly distributed nano-sheets that endow the surface with excellent superhydrophobicity (WCA: 164.2°; WSA: below 5°). Besides, the as-prepared etched-immersed Al/STA superhydrophobic surface on Al foil exhibits good friction-reducing ability and stable superhydrophobicity. - Highlights: • A stable superhydrophobic surface was created on aluminum foil by a facile three-step solution–immersion method. • A lotus-leaf-like hierarchical structure consists of interconnected convex–concave micro-structure and uniformly distributed nano-sheets has been constructed on the aluminum surface. • The superhydrophobic surfaces on aluminum substrate showing effective friction-reducing performance and self-cleaning ability. - Abstract: A lotus-leaf-like hierarchical structure with superhydrophobicity was created on Al foil by a facile three-step solution–immersion method involving etching in hydrochloric acid solution and immersing in hot water as well as surface-modification by stearic acid (denoted as STA). As-prepared etched-immersed Al/STA rough surface was characterized by means of scanning electron microscopy and X-ray photoelectron spectroscopy. Moreover, the water contact angles and water sliding angles of as-prepared etched-immersed Al/STA rough surface were measured, and the friction-reducing performance and self-cleaning ability of the as-prepared surface were also evaluated. Results indicate that the etched-immersed Al/STA rough surface consists of interconnected convex–concave micro-structure and uniformly distributed nano-sheets. Besides, it exhibits stable superhydrophobicity and good friction-reducing ability. Namely, it has a contact angle of water as high as 164.2° and a water sliding

  20. Fabrication and characterization of stable superhydrophobic surface with good friction-reducing performance on Al foil

    International Nuclear Information System (INIS)

    Li, Peipei; Chen, Xinhua; Yang, Guangbin; Yu, Laigui; Zhang, Pingyu

    2014-01-01

    Graphical abstract: A lotus-leaf-like hierarchical structure was successfully created on Al foil by a facile three-step solution–immersion method. As-obtained etched-immersed Al/STA rough surface contains interconnected convex–concave micro-structure and uniformly distributed nano-sheets that endow the surface with excellent superhydrophobicity (WCA: 164.2°; WSA: below 5°). Besides, the as-prepared etched-immersed Al/STA superhydrophobic surface on Al foil exhibits good friction-reducing ability and stable superhydrophobicity. - Highlights: • A stable superhydrophobic surface was created on aluminum foil by a facile three-step solution–immersion method. • A lotus-leaf-like hierarchical structure consists of interconnected convex–concave micro-structure and uniformly distributed nano-sheets has been constructed on the aluminum surface. • The superhydrophobic surfaces on aluminum substrate showing effective friction-reducing performance and self-cleaning ability. - Abstract: A lotus-leaf-like hierarchical structure with superhydrophobicity was created on Al foil by a facile three-step solution–immersion method involving etching in hydrochloric acid solution and immersing in hot water as well as surface-modification by stearic acid (denoted as STA). As-prepared etched-immersed Al/STA rough surface was characterized by means of scanning electron microscopy and X-ray photoelectron spectroscopy. Moreover, the water contact angles and water sliding angles of as-prepared etched-immersed Al/STA rough surface were measured, and the friction-reducing performance and self-cleaning ability of the as-prepared surface were also evaluated. Results indicate that the etched-immersed Al/STA rough surface consists of interconnected convex–concave micro-structure and uniformly distributed nano-sheets. Besides, it exhibits stable superhydrophobicity and good friction-reducing ability. Namely, it has a contact angle of water as high as 164.2° and a water sliding

  1. RNA–Stable-Isotope Probing Shows Utilization of Carbon from Inulin by Specific Bacterial Populations in the Rat Large Bowel

    Science.gov (United States)

    Lawley, Blair; Munro, Karen; Sims, Ian M.; Lee, Julian; Butts, Christine A.; Roy, Nicole

    2014-01-01

    Knowledge of the trophisms that underpin bowel microbiota composition is required in order to understand its complex phylogeny and function. Stable-isotope (13C)-labeled inulin was added to the diet of rats on a single occasion in order to detect utilization of inulin-derived substrates by particular members of the cecal microbiota. Cecal digesta from Fibruline-inulin-fed rats was collected prior to (0 h) and at 6, 12, 18 and 24 h following provision of the [13C]inulin diet. RNA was extracted from these cecal specimens and fractionated in isopycnic buoyant density gradients in order to detect 13C-labeled nucleic acid originating in bacterial cells that had metabolized the labeled dietary constituent. RNA extracted from specimens collected after provision of the labeled diet was more dense than 0-h RNA. Sequencing of 16S rRNA genes amplified from cDNA obtained from these fractions showed that Bacteroides uniformis, Blautia glucerasea, Clostridium indolis, and Bifidobacterium animalis were the main users of the 13C-labeled substrate. Culture-based studies of strains of these bacterial species enabled trophisms associated with inulin and its hydrolysis products to be identified. B. uniformis utilized Fibruline-inulin for growth, whereas the other species used fructo-oligosaccharide and monosaccharides. Thus, RNA–stable-isotope probing (RNA-SIP) provided new information about the use of carbon from inulin in microbiota metabolism. PMID:24487527

  2. Experimental and numerical investigations of stable crack growth of axial surface flaws in a pressure vessel

    International Nuclear Information System (INIS)

    Brocks, W.; Krafka, H.; Mueller, W.; Wobst, K.

    1988-01-01

    In connection with the problem of the transferability of parameters obtained experimentally with the help of fracture-mechanical test specimens and used for the initiation and the stable propagation of cracks in cases of pulsating stress and of the elasto-plastic behaviour of construction components, a pressure vessel with an inside diameter of 1500 mm, a cylindrical length of 3000 mm and a wall thickness of 40 mm was hydraulically loaded with the help of internal pressure in the first stage, to attain an average crack growth of 1 mm at Δ a ≅, the loading taking place at about 21deg C. This stress-free annealed vessel exhibited an axial semielliptical vibration-induced surface crack about 181 mm long and 20 mm deep, as a test defect, in a welded circular blank made of the steel 20MnMoNi 55. The fractographic analysis of the first stable crack revealed that its growth rate of Δa was highest in the area of transition from the weak to the strong bend of the crack front (55deg m /σ v (average principal stress: σ m , Mises' reference stress: σ v v). A comparison of the experimental with the numerical results from the first stable crack shows that the local stable crack growth Δa cannot be calculated solely with reference to J, because Δa appears to depend essentially on the quotient σ m /σ v . (orig./MM) [de

  3. Stable perovskite solar cells by surface modification with surfactant molecules

    Energy Technology Data Exchange (ETDEWEB)

    Holanda, Matheus Serra de; Nogueira, Ana Flavia, E-mail: mholandabsb@outlook.com [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Instituto de Quimica

    2016-07-01

    Full text: Surface modification on organic-inorganic perovskite films using dodecylammonium chloride was done to improve the stability of the material over the air moisture, which is considered extremely harmful to these materials and complicates their application on solar cell technology. Perovskite CH{sub 3}NH{sub 3}PbI{sub 3} was prepared by single step method using a solution containing PbI{sub 2} and CH{sub 3}NH{sub 3}I on DMF:DMSO (2:1) on a concentration of 0.88 mol L{sup -1}. The film was deposited over a planar film of TiO{sub 2}, previously deposited over FTO glass, by using spin-casting method. 25 μL of the solution was spread over the substrate which was turned at 4000 RPM for 45 s. In the last 10 s, 800 μL of monochlorobenzene was dropped. The film was submitted to a thermal treatment so the conversion of the perovskite could be completed. After the thermal treatment, the modifier was spin coated over the perovskite film from 5 and 10 mg mL{sup -1} solutions of the dodecylammonium chloride in chloroform. The perovskite films were characterized by SEM, XRD and UV-Vis spectroscopy. SEM images have shown that the modifiers agglomerate and they cover the perovskite film, forming a protection layer. XRD and UV-Vis carried out after the film preparation, 7 and 15 days after the deposition. The first results show that the protection layer is able to avoid degradation of the perovskite film. Photovoltaic devices were prepared by depositing Spiro-OMeTAD as HTM layer and gold as electrode. It was observed that the increase on the thickness of the surfactant layer causes a decrease on the short-circuit current density (JSC), which is expected since is starts to act like an insulating layer. This effect is also the cause of the reduction of the fill factor (FF). More experiments need to be carried out to improve the solar cells devices, but the present data has shown the potential of the method developed, which uses easy access surfactants and a simple

  4. Stable perovskite solar cells by surface modification with surfactant molecules

    International Nuclear Information System (INIS)

    Holanda, Matheus Serra de; Nogueira, Ana Flavia

    2016-01-01

    Full text: Surface modification on organic-inorganic perovskite films using dodecylammonium chloride was done to improve the stability of the material over the air moisture, which is considered extremely harmful to these materials and complicates their application on solar cell technology. Perovskite CH 3 NH 3 PbI 3 was prepared by single step method using a solution containing PbI 2 and CH 3 NH 3 I on DMF:DMSO (2:1) on a concentration of 0.88 mol L -1 . The film was deposited over a planar film of TiO 2 , previously deposited over FTO glass, by using spin-casting method. 25 μL of the solution was spread over the substrate which was turned at 4000 RPM for 45 s. In the last 10 s, 800 μL of monochlorobenzene was dropped. The film was submitted to a thermal treatment so the conversion of the perovskite could be completed. After the thermal treatment, the modifier was spin coated over the perovskite film from 5 and 10 mg mL -1 solutions of the dodecylammonium chloride in chloroform. The perovskite films were characterized by SEM, XRD and UV-Vis spectroscopy. SEM images have shown that the modifiers agglomerate and they cover the perovskite film, forming a protection layer. XRD and UV-Vis carried out after the film preparation, 7 and 15 days after the deposition. The first results show that the protection layer is able to avoid degradation of the perovskite film. Photovoltaic devices were prepared by depositing Spiro-OMeTAD as HTM layer and gold as electrode. It was observed that the increase on the thickness of the surfactant layer causes a decrease on the short-circuit current density (JSC), which is expected since is starts to act like an insulating layer. This effect is also the cause of the reduction of the fill factor (FF). More experiments need to be carried out to improve the solar cells devices, but the present data has shown the potential of the method developed, which uses easy access surfactants and a simple preparation method to improve the stability of

  5. Is bicarbonate stable in and on the calcite surface?

    DEFF Research Database (Denmark)

    Andersson, Martin Peter; Rodriguez Blanco, Juan Diego; Stipp, Susan Louise Svane

    2016-01-01

    We have used density functional theory with the COSMO-RS implicit solvent model to predict the pKa for the deprotonation of bicarbonate to carbonate, i.e. HCO3− CO32− + H+, when HCO3− is included in, and adsorbed on, a calcite surface. We have used cluster models (80–100 atoms) to represent...... the flat {10.4} surface, acute steps, obtuse steps, two types of kinks on the acute step and two types of kinks on the obtuse steps. Based on the predicted pKa values, which range from −6.0 to 2.4 depending on the surface site, we conclude that bicarbonate deprotonates to carbonate when it is in calcite...... even when pH in solution is very low. This is true for all surface sites, even for solutions where 2.4 bicarbonate is adsorbed on calcite, the predicted pKa for deprotonation is 7.5, which is ∼3 pH units lower than in aqueous solution...

  6. Thermochemistry of minerals stable near the earth's surface

    International Nuclear Information System (INIS)

    1990-01-01

    The present proposal continues the evolution, of changing emphasis from silicate melts to glass and toward crystalline minerals stable in the shallow crustal environment, particularly amphiholes, micas, and related hydrous phases adding zeolites and carbonates to our areas of interest. This is made possible both by recent advances in our high-temperature calorimetric techniques and by an interest in extending our ideas about the systematics of ionic substitutions to more complex structures. The proposal presents the following: (a) a listing of papers, theses, and abstracts in the past 3 years supported by the present grant, (b) a summary of work on glasses containing highly charged cations and on some related crystalline phases, with proposed new directions, (c) a discussion of advances in calorimetric methods and what new possibilities they open, (d) completed and planned work on amphiboles, micas, and clays, (e) completed and proposed work on amorpous low temperature materials, (f) proposed work on zeolites, and (g) proposed work on carbonates and (h) a discussion of the energy relevance of the above projects. This is followed by the required forms, budget pages, and CV. 34 refs., 5 figs., 1 tab

  7. Modelling the artic stable boundary layer and its coupling to the surface

    NARCIS (Netherlands)

    Steeneveld, G.J.; Wiel, van de B.J.H.; Holtslag, A.A.M.

    2006-01-01

    The impact of coupling the atmosphere to the surface energy balance is examined for the stable boundary layer, as an extension of the first GABLS (GEWEX Atmospheric Boundary-Layer Study) one-dimensional model intercomparison. This coupling is of major importance for the stable boundary-layer

  8. Surface oceanographic fronts influencing deep-sea biological activity: Using fish stable isotopes as ecological tracers

    Science.gov (United States)

    Louzao, Maite; Navarro, Joan; Delgado-Huertas, Antonio; de Sola, Luis Gil; Forero, Manuela G.

    2017-06-01

    Ecotones can be described as transition zones between neighbouring ecological systems that can be shaped by environmental gradients over a range of space and time scales. In the marine environment, the detection of ecotones is complex given the highly dynamic nature of marine systems and the paucity of empirical data over ocean-basin scales. One approach to overcome these limitations is to use stable isotopes from animal tissues since they can track spatial oceanographic variability across marine systems and, in turn, can be used as ecological tracers. Here, we analysed stable isotopes of deep-sea fishes to assess the presence of ecological discontinuities across the western Mediterranean. We were specifically interested in exploring the connection between deep-sea biological activity and particular oceanographic features (i.e., surface fronts) occurring in the pelagic domain. We collected samples for three different abundant deep-sea species in May 2004 from an experimental oceanographic trawling cruise (MEDITS): the Mictophydae jewel lanternfish Lampanyctus crocodilus and two species of the Gadidae family, the silvery pout Gadiculus argenteus and the blue whiting Micromesistius poutassou. The experimental survey occurred along the Iberian continental shelf and the upper and middle slopes, from the Strait of Gibraltar in the SW to the Cape Creus in the NE. The three deep-sea species were highly abundant throughout the study area and they showed geographic variation in their isotopic values, with decreasing values from north to south disrupted by an important change point around the Vera Gulf. Isotopic latitudinal gradients were explained by pelagic oceanographic conditions along the study area and confirm the existence of an ecotone at the Vera Gulf. This area could be considered as an oceanographic boundary where waters of Atlantic origin meet Mediterranean surface waters forming important frontal structures such as the Almeria-Oran front. In fact, our results

  9. Polyaniline hybridized surface defective ZnO nanorods with long-term stable photoelectrochemical activity

    International Nuclear Information System (INIS)

    Bera, Susanta; Khan, Hasmat; Biswas, Indranil; Jana, Sunirmal

    2016-01-01

    Highlights: • Polyaniline (PANI) hybridized ZnO nanorods was synthesized by solution method. • Surface defects were found in the nanorods. • The hybrid material exhibited an enhancement in visible light absorption. • A long-term stable photoelectrochemical activity of the material was found. • Advancement in the properties would be PANI hybridization and surface defects. - Abstract: We report surfactant/template free precursor solution based synthesis of polyaniline (PANI) hybridized surface defective ZnO nanorods by a two-step process. Initially, ZnO nanorods have been prepared at 95 °C, followed by hybridization (coating) of PANI onto the ZnO via in situ polymerization of aniline monomer, forming ZnO-PANI nanohybrid (ZP). The structural properties of ZP have been analyzed by X-ray diffraction (XRD) and transmission electron microscopic (TEM) studies. The presence of surface defects especially the oxygen vacancies in ZnO has been characterized by photoluminescence emission, high resolution TEM, X-ray photoelectron spectroscopy (XPS) and micro-Raman spectral measurements. The chemical interaction of PANI with ZnO has been examined by Fourier transform infrared (FTIR) and XPS analyses. A significant enhancement in visible absorption of ZP sample is found as evidenced from UV–vis diffused reflectance spectral study. BET nitrogen adsorption-desorption isotherm shows an improved textural property (pore size, pore volume) of ZP. Moreover, a long-term stable photoelectrochemical activity (PEC) of ZP is found compare to pristine ZnO. The synergic effect of PANI hybridization and the presence of surface defects in ZnO NRs can enhance the PEC by prolonging the recombination rate of photogenerated charge carriers. The effect can also provide large number of active sites to make electrolyte diffusion and mass transportation easier in the nanohybrid. This simple synthesis strategy can be adopted for PANI hybridization with different metal oxide semiconductors

  10. Polyaniline hybridized surface defective ZnO nanorods with long-term stable photoelectrochemical activity

    Energy Technology Data Exchange (ETDEWEB)

    Bera, Susanta; Khan, Hasmat [Sol-Gel Division, CSIR-Central Glass and Ceramic Research Institute (CSIR-CGCRI), 196 Raja S.C. Mullick Road, P.O. Jadavpur University, Kolkata 700 032, West Bengal (India); Biswas, Indranil [Materials Characterization and Instrumentation Division, CSIR-Central Glass and Ceramic Research Institute (CSIR-CGCRI), 196 Raja S.C. Mullick Road, P.O. Jadavpur University, Kolkata 700 032, West Bengal (India); Jana, Sunirmal, E-mail: sjana@cgcri.res.in [Sol-Gel Division, CSIR-Central Glass and Ceramic Research Institute (CSIR-CGCRI), 196 Raja S.C. Mullick Road, P.O. Jadavpur University, Kolkata 700 032, West Bengal (India)

    2016-10-15

    Highlights: • Polyaniline (PANI) hybridized ZnO nanorods was synthesized by solution method. • Surface defects were found in the nanorods. • The hybrid material exhibited an enhancement in visible light absorption. • A long-term stable photoelectrochemical activity of the material was found. • Advancement in the properties would be PANI hybridization and surface defects. - Abstract: We report surfactant/template free precursor solution based synthesis of polyaniline (PANI) hybridized surface defective ZnO nanorods by a two-step process. Initially, ZnO nanorods have been prepared at 95 °C, followed by hybridization (coating) of PANI onto the ZnO via in situ polymerization of aniline monomer, forming ZnO-PANI nanohybrid (ZP). The structural properties of ZP have been analyzed by X-ray diffraction (XRD) and transmission electron microscopic (TEM) studies. The presence of surface defects especially the oxygen vacancies in ZnO has been characterized by photoluminescence emission, high resolution TEM, X-ray photoelectron spectroscopy (XPS) and micro-Raman spectral measurements. The chemical interaction of PANI with ZnO has been examined by Fourier transform infrared (FTIR) and XPS analyses. A significant enhancement in visible absorption of ZP sample is found as evidenced from UV–vis diffused reflectance spectral study. BET nitrogen adsorption-desorption isotherm shows an improved textural property (pore size, pore volume) of ZP. Moreover, a long-term stable photoelectrochemical activity (PEC) of ZP is found compare to pristine ZnO. The synergic effect of PANI hybridization and the presence of surface defects in ZnO NRs can enhance the PEC by prolonging the recombination rate of photogenerated charge carriers. The effect can also provide large number of active sites to make electrolyte diffusion and mass transportation easier in the nanohybrid. This simple synthesis strategy can be adopted for PANI hybridization with different metal oxide semiconductors

  11. Smart biomaterials: Surfaces functionalized with proteolytically stable osteoblast-adhesive peptides

    Directory of Open Access Journals (Sweden)

    Annj Zamuner

    2017-09-01

    Full Text Available Engineered scaffolds for bone tissue regeneration are designed to promote cell adhesion, growth, proliferation and differentiation. Recently, covalent and selective functionalization of glass and titanium surfaces with an adhesive peptide (HVP mapped on [351–359] sequence of human Vitronectin allowed to selectively increase osteoblast attachment and adhesion strength in in vitro assays, and to promote osseointegration in in vivo studies. For the first time to our knowledge, in this study we investigated the resistance of adhesion sequences to proteolytic digestion: HVP was completely cleaved after 5 h. In order to overcome the enzymatic degradation of the native peptide under physiological conditions we synthetized three analogues of HVP sequence. A retro-inverted peptide D-2HVP, composed of D amino acids, was completely stable in serum-containing medium. In addition, glass surfaces functionalized with D-2HVP increased human osteoblast adhesion as compared to the native peptide and maintained deposition of calcium. Interestingly, D-2HVP increased expression of IBSP, VTN and SPP1 genes as compared to HVP functionalized surfaces. Total internal reflection fluorescence microscope analysis showed cells with numerous filopodia spread on D-2HVP-functionalized surfaces. Therefore, the D-2HVP sequence is proposed as new osteoblast adhesive peptide with increased bioactivity and high proteolytic resistance.

  12. Smart biomaterials: Surfaces functionalized with proteolytically stable osteoblast-adhesive peptides.

    Science.gov (United States)

    Zamuner, Annj; Brun, Paola; Scorzeto, Michele; Sica, Giuseppe; Castagliuolo, Ignazio; Dettin, Monica

    2017-09-01

    Engineered scaffolds for bone tissue regeneration are designed to promote cell adhesion, growth, proliferation and differentiation. Recently, covalent and selective functionalization of glass and titanium surfaces with an adhesive peptide (HVP) mapped on [351-359] sequence of human Vitronectin allowed to selectively increase osteoblast attachment and adhesion strength in in vitro assays, and to promote osseointegration in in vivo studies. For the first time to our knowledge, in this study we investigated the resistance of adhesion sequences to proteolytic digestion: HVP was completely cleaved after 5 h. In order to overcome the enzymatic degradation of the native peptide under physiological conditions we synthetized three analogues of HVP sequence. A retro-inverted peptide D-2HVP, composed of D amino acids, was completely stable in serum-containing medium. In addition, glass surfaces functionalized with D-2HVP increased human osteoblast adhesion as compared to the native peptide and maintained deposition of calcium. Interestingly, D-2HVP increased expression of IBSP, VTN and SPP1 genes as compared to HVP functionalized surfaces. Total internal reflection fluorescence microscope analysis showed cells with numerous filopodia spread on D-2HVP-functionalized surfaces. Therefore, the D-2HVP sequence is proposed as new osteoblast adhesive peptide with increased bioactivity and high proteolytic resistance.

  13. Stable water isotope simulation by current land-surface schemes:Results of IPILPS phase 1

    Energy Technology Data Exchange (ETDEWEB)

    Henderson-Sellers, A.; Fischer, M.; Aleinov, I.; McGuffie, K.; Riley, W.J.; Schmidt, G.A.; Sturm, K.; Yoshimura, K.; Irannejad, P.

    2005-10-31

    Phase 1 of isotopes in the Project for Intercomparison of Land-surface Parameterization Schemes (iPILPS) compares the simulation of two stable water isotopologues ({sup 1}H{sub 2} {sup 18}O and {sup 1}H{sup 2}H{sup 16}O) at the land-atmosphere interface. The simulations are off-line, with forcing from an isotopically enabled regional model for three locations selected to offer contrasting climates and ecotypes: an evergreen tropical forest, a sclerophyll eucalypt forest and a mixed deciduous wood. Here we report on the experimental framework, the quality control undertaken on the simulation results and the method of intercomparisons employed. The small number of available isotopically-enabled land-surface schemes (ILSSs) limits the drawing of strong conclusions but, despite this, there is shown to be benefit in undertaking this type of isotopic intercomparison. Although validation of isotopic simulations at the land surface must await more, and much more complete, observational campaigns, we find that the empirically-based Craig-Gordon parameterization (of isotopic fractionation during evaporation) gives adequately realistic isotopic simulations when incorporated in a wide range of land-surface codes. By introducing two new tools for understanding isotopic variability from the land surface, the Isotope Transfer Function and the iPILPS plot, we show that different hydrological parameterizations cause very different isotopic responses. We show that ILSS-simulated isotopic equilibrium is independent of the total water and energy budget (with respect to both equilibration time and state), but interestingly the partitioning of available energy and water is a function of the models' complexity.

  14. Stable isotope composition of surface and groundwater in Baja California, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Kretzschmar, Thomas G. [CICESE, Carret. Ensenada-Tijuana No 3819, Ensenada 22860 (Mexico); Frommen, Theresa [FU Berlin Malteserstr. 74-100, 12249 Berlin (Germany)

    2013-07-01

    Based on a total of 135 stable isotope analysis (δ{sup 18}O, δD) carried out on surface and groundwater samples, as well as on rainwater samples between 2004 and 2011 in 5 different regions in Baja California, an isotopic evaluation of the region was established. The results showed a depletion gradient of -0.25 0/00 δ{sup 18}O per 100 m rise in elevation throughout the study area. Considering an unaltered δ{sup 18}O signature for the thermal springs, the recharge areas of these waters are at elevations over 1400 m outside of the present watersheds, indicating the presence of regional flow systems next to the local flow regime feeding the cold springs and wells. The Mesa de Andrade area has a completely different signature with values of -105 for δ{sup 18}O and -13 for δD. (authors)

  15. Stable isotope composition of surface and groundwater in Baja California, Mexico

    International Nuclear Information System (INIS)

    Kretzschmar, Thomas G.; Frommen, Theresa

    2013-01-01

    Based on a total of 135 stable isotope analysis (δ 18 O, δD) carried out on surface and groundwater samples, as well as on rainwater samples between 2004 and 2011 in 5 different regions in Baja California, an isotopic evaluation of the region was established. The results showed a depletion gradient of -0.25 0/00 δ 18 O per 100 m rise in elevation throughout the study area. Considering an unaltered δ 18 O signature for the thermal springs, the recharge areas of these waters are at elevations over 1400 m outside of the present watersheds, indicating the presence of regional flow systems next to the local flow regime feeding the cold springs and wells. The Mesa de Andrade area has a completely different signature with values of -105 for δ 18 O and -13 for δD. (authors)

  16. Dual-band frequency selective surface with large band separation and stable performance

    Science.gov (United States)

    Zhou, Hang; Qu, Shao-Bo; Peng, Wei-Dong; Lin, Bao-Qin; Wang, Jia-Fu; Ma, Hua; Zhang, Jie-Qiu; Bai, Peng; Wang, Xu-Hua; Xu, Zhuo

    2012-05-01

    A new technique of designing a dual-band frequency selective surface with large band separation is presented. This technique is based on a delicately designed topology of L- and Ku-band microwave filters. The two band-pass responses are generated by a capacitively-loaded square-loop frequency selective surface and an aperture-coupled frequency selective surface, respectively. A Faraday cage is located between the two frequency selective surface structures to eliminate undesired couplings. Based on this technique, a dual-band frequency selective surface with large band separation is designed, which possesses large band separation, high selectivity, and stable performance under various incident angles and different polarizations.

  17. Genes with stable DNA methylation levels show higher evolutionary conservation than genes with fluctuant DNA methylation levels.

    Science.gov (United States)

    Zhang, Ruijie; Lv, Wenhua; Luan, Meiwei; Zheng, Jiajia; Shi, Miao; Zhu, Hongjie; Li, Jin; Lv, Hongchao; Zhang, Mingming; Shang, Zhenwei; Duan, Lian; Jiang, Yongshuai

    2015-11-24

    Different human genes often exhibit different degrees of stability in their DNA methylation levels between tissues, samples or cell types. This may be related to the evolution of human genome. Thus, we compared the evolutionary conservation between two types of genes: genes with stable DNA methylation levels (SM genes) and genes with fluctuant DNA methylation levels (FM genes). For long-term evolutionary characteristics between species, we compared the percentage of the orthologous genes, evolutionary rate dn/ds and protein sequence identity. We found that the SM genes had greater percentages of the orthologous genes, lower dn/ds, and higher protein sequence identities in all the 21 species. These results indicated that the SM genes were more evolutionarily conserved than the FM genes. For short-term evolutionary characteristics among human populations, we compared the single nucleotide polymorphism (SNP) density, and the linkage disequilibrium (LD) degree in HapMap populations and 1000 genomes project populations. We observed that the SM genes had lower SNP densities, and higher degrees of LD in all the 11 HapMap populations and 13 1000 genomes project populations. These results mean that the SM genes had more stable chromosome genetic structures, and were more conserved than the FM genes.

  18. Covalent and stable CuAAC modification of silicon surfaces for control of cell adhesion

    DEFF Research Database (Denmark)

    Vutti, Surendra; Buch-Månson, Nina; Schoffelen, Sanne

    2015-01-01

    in the vapor or liquid phase. In this work, we compared these two methods for oxidized silicon surfaces and thoroughly characterized the functionalization steps by tagging and fluorescence imaging. We demonstrate that the vapor-phase functionalization only provided transient surface modification that was lost...... on extensive washing. For stable surface modification, a liquid-phase method was developed. In this method, silicon wafers were decorated with azides, either by silanization with (3-azidopropyl)triethoxysilane or by conversion of the amine groups of an aminopropylated surface by means of the azido...

  19. Surface Passivation for 3-5 Semiconductor Processing: Stable Gallium Sulphide Films by MOCVD

    Science.gov (United States)

    Macinnes, Andrew N.; Jenkins, Phillip P.; Power, Michael B.; Kang, Soon; Barron, Andrew R.; Hepp, Aloysius F.; Tabib-Azar, Massood

    1994-01-01

    Gallium sulphide (GaS) has been deposited on GaAs to form stable, insulating, passivating layers. Spectrally resolved photoluminescence and surface recombination velocity measurements indicate that the GaS itself can contribute a significant fraction of the photoluminescence in GaS/GaAs structures. Determination of surface recombination velocity by photoluminescence is therefore difficult. By using C-V analysis of metal-insulator-semiconductor structures, passivation of the GaAs with GaS films is quantified.

  20. A stable high-order perturbation of surfaces method for numerical simulation of diffraction problems in triply layered media

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Youngjoon, E-mail: hongy@uic.edu; Nicholls, David P., E-mail: davidn@uic.edu

    2017-02-01

    The accurate numerical simulation of linear waves interacting with periodic layered media is a crucial capability in engineering applications. In this contribution we study the stable and high-order accurate numerical simulation of the interaction of linear, time-harmonic waves with a periodic, triply layered medium with irregular interfaces. In contrast with volumetric approaches, High-Order Perturbation of Surfaces (HOPS) algorithms are inexpensive interfacial methods which rapidly and recursively estimate scattering returns by perturbation of the interface shape. In comparison with Boundary Integral/Element Methods, the stable HOPS algorithm we describe here does not require specialized quadrature rules, periodization strategies, or the solution of dense non-symmetric positive definite linear systems. In addition, the algorithm is provably stable as opposed to other classical HOPS approaches. With numerical experiments we show the remarkable efficiency, fidelity, and accuracy one can achieve with an implementation of this algorithm.

  1. Microbial communities of the Lemon Creek Glacier show subtle structural variation yet stable phylogenetic composition over space and time

    Directory of Open Access Journals (Sweden)

    Cody Springer Sheik

    2015-05-01

    Full Text Available Glaciers are geologically important yet transient ecosystems that support diverse, biogeochemically significant microbial communities. During the melt season glaciers undergo dramatic physical, geochemical and biological changes that exert great influence on downstream biogeochemical cycles. Thus, we sought to understand the temporal melt-season dynamics of microbial communities and associated geochemistry at the terminus of Lemon Creek Glacier (LCG in coastal southern Alaska. Due to late season snowfall, sampling of LCG occurred in three interconnected areas: proglacial Lake Thomas, the lower glacial outflow stream and the glacier’s terminus. LCG associated microbial communities were phylogenetically diverse and varied by sampling location. However, Betaproteobacteria, Alphaproteobacteria and Bacteroidetes dominated communities at all sampling locations. Strict anaerobic groups such as methanogens, SR1, and OP11 were also recovered from glacier outflows, indicating anoxic conditions in at least some portions of the LCG subglacial environment. Microbial community structure was significantly correlated with sampling location and sodium concentrations. Microbial communities sampled from terminus outflow waters exhibited day-to-day fluctuation in taxonomy and phylogenetic similarity. However, these communities were not significantly different from randomly constructed communities from all three sites. These results indicate that glacial outflows share a large proportion of phylogenetic overlap with downstream environments and that the observed significant shifts in community structure are driven by changes in relative abundance of different taxa, and not complete restructuring of communities. We conclude that LCG glacial discharge hosts a diverse and relatively stable microbiome that shifts at fine taxonomic scales in response to geochemistry and likely water residence time.

  2. Stable water isotopes in the coupled atmosphere–land surface model ECHAM5-JSBACH

    Directory of Open Access Journals (Sweden)

    B. Haese

    2013-09-01

    Full Text Available In this study we present first results of a new model development, ECHAM5-JSBACH-wiso, where we have incorporated the stable water isotopes H218O and HDO as tracers in the hydrological cycle of the coupled atmosphere–land surface model ECHAM5-JSBACH. The ECHAM5-JSBACH-wiso model was run under present-day climate conditions at two different resolutions (T31L19, T63L31. A comparison between ECHAM5-JSBACH-wiso and ECHAM5-wiso shows that the coupling has a strong impact on the simulated temperature and soil wetness. Caused by these changes of temperature and the hydrological cycle, the δ18O in precipitation also shows variations from −4‰ up to 4‰. One of the strongest anomalies is shown over northeast Asia where, due to an increase of temperature, the δ18O in precipitation increases as well. In order to analyze the sensitivity of the fractionation processes over land, we compare a set of simulations with various implementations of these processes over the land surface. The simulations allow us to distinguish between no fractionation, fractionation included in the evaporation flux (from bare soil and also fractionation included in both evaporation and transpiration (from water transport through plants fluxes. While the isotopic composition of the soil water may change for δ18O by up to +8&permil:, the simulated δ18O in precipitation shows only slight differences on the order of ±1‰. The simulated isotopic composition of precipitation fits well with the available observations from the GNIP (Global Network of Isotopes in Precipitation database.

  3. Synthesis of Stable Interfaces on SnO2 Surfaces for Charge-Transfer Applications

    Science.gov (United States)

    Benson, Michelle C.

    The commercial market for solar harvesting devices as an alternative energy source requires them to be both low-cost and efficient to replace or reduce the dependence on fossil fuel burning. Over the last few decades there has been promising efforts towards improving solar devices by using abundant and non-toxic metal oxide nanomaterials. One particular metal oxide of interest has been SnO2 due to its high electron mobility, wide-band gap, and aqueous stability. However SnO2 based solar cells have yet to reach efficiency values of other metal oxides, like TiO2. The advancement of SnO2 based devices is dependent on many factors, including improved methods of surface functionalization that can yield stable interfaces. This work explores the use of a versatile functionalization method through the use of the Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction. The CuAAC reaction is capable of producing electrochemically, photochemically, and electrocatalytically active surfaces on a variety of SnO2 materials. The resulting charge-transfer characteristics were investigated as well as an emphasis on understanding the stability of the resulting molecular linkage. We determined the CuAAC reaction is able to proceed through both azide-modified and alkyne-modified surfaces. The resulting charge-transfer properties showed that the molecular tether was capable of supporting charge separation at the interface. We also investigated the enhancement of electron injection upon the introduction of an ultra-thin ZrO2 coating on SnO2. Several complexes were used to fully understand the charge-transfer capabilities, including model systems of ferrocene and a ruthenium coordination complex, a ruthenium mononuclear water oxidation catalyst, and a commercial ruthenium based dye.

  4. TGP, an extremely stable, non-aggregating fluorescent protein created by structure-guided surface engineering

    OpenAIRE

    Close, Devin W.; Don Paul, Craig; Langan, Patricia S.; Wilce, Matthew C.J.; Traore, Daouda A.K.; Halfmann, Randal; Rocha, Reginaldo C.; Waldo, Geoffery S.; Payne, Riley J.; Rucker, Joseph B.; Prescott, Mark; Bradbury, Andrew R.M.

    2015-01-01

    In this paper we describe the engineering and X-ray crystal structure of Thermal Green Protein (TGP), an extremely stable, highly soluble, non-aggregating green fluorescent protein. TGP is a soluble variant of the fluorescent protein eCGP123, which despite being highly stable, has proven to be aggregation-prone. The X-ray crystal structure of eCGP123, also determined within the context of this paper, was used to carry out rational surface engineering to improve its solubility, leading to TGP....

  5. Hydrophobic and Metallophobic Surfaces: Highly Stable Non-wetting Inorganic Surfaces Based on Lanthanum Phosphate Nanorods.

    Science.gov (United States)

    Sankar, Sasidharan; Nair, Balagopal N; Suzuki, Takehiro; Anilkumar, Gopinathan M; Padmanabhan, Moothetty; Hareesh, Unnikrishnan Nair S; Warrier, Krishna G

    2016-03-09

    Metal oxides, in general, are known to exhibit significant wettability towards water molecules because of the high feasibility of synergetic hydrogen-bonding interactions possible at the solid-water interface. Here we show that the nano sized phosphates of rare earth materials (Rare Earth Phosphates, REPs), LaPO4 in particular, exhibit without any chemical modification, unique combination of intrinsic properties including remarkable hydrophobicity that could be retained even after exposure to extreme temperatures and harsh hydrothermal conditions. Transparent nanocoatings of LaPO4 as well as mixture of other REPs on glass surfaces are shown to display notable hydrophobicity with water contact angle (WCA) value of 120° while sintered and polished monoliths manifested WCA greater than 105°. Significantly, these materials in the form of coatings and monoliths also exhibit complete non-wettability and inertness towards molten metals like Ag, Zn, and Al well above their melting points. These properties, coupled with their excellent chemical and thermal stability, ease of processing, machinability and their versatile photo-physical and emission properties, render LaPO4 and other REP ceramics utility in diverse applications.

  6. Production of stable superhydrophilic surfaces on 316L steel by simultaneous laser texturing and SiO2 deposition

    Science.gov (United States)

    Rajab, Fatema H.; Liu, Zhu; Li, Lin

    2018-01-01

    Superhydrophilic surfaces with liquid contact angles of less than 5 ° have attracted much interest in practical applications including self-cleaning, cell manipulation, adhesion enhancement, anti-fogging, fluid flow control and evaporative cooling. Standard laser metal texturing method often result in unstable wetting characteristics, i.e. changing from super hydrophilic to hydrophobic in a few days or weeks. In this paper, a simple one step method is reported for fabricating a stable superhydrophilic metallic surface that lasted for at least 6 months. Here, 316L stainless steel substrates were textured using a nanosecond laser with in-situ SiO2 deposition. Morphology and chemistry of laser-textured surfaces were characterised using SEM, XRD, XPS and an optical 3D profiler. Static wettability analysis was carried out over a period of 6 months after the laser treatment. The effect of surface roughness on wettability was also studied. Results showed that the wettability of the textured surfaces could be controlled by changing the scanning speed of laser beam and number of passes. The main reason for the realisation of the stable superhydrophilic surface is the combination of the melted glass particles mainly Si and O with that of stainless steel in the micro-textured patterns. This study presents a useful method

  7. Design and Fabrication of a Hybrid Superhydrophobic-Hydrophilic Surface That Exhibits Stable Dropwise Condensation.

    Science.gov (United States)

    Mondal, Bikash; Mac Giolla Eain, Marc; Xu, QianFeng; Egan, Vanessa M; Punch, Jeff; Lyons, Alan M

    2015-10-28

    Condensation of water vapor is an essential process in power generation, water collection, and thermal management. Dropwise condensation, where condensed droplets are removed from the surface before coalescing into a film, has been shown to increase the heat transfer efficiency and water collection ability of many surfaces. Numerous efforts have been made to create surfaces which can promote dropwise condensation, including superhydrophobic surfaces on which water droplets are highly mobile. However, the challenge with using such surfaces in condensing environments is that hydrophobic coatings can degrade and/or water droplets on superhydrophobic surfaces transition from the mobile Cassie to the wetted Wenzel state over time and condensation shifts to a less-effective filmwise mechanism. To meet the need for a heat-transfer surface that can maintain stable dropwise condensation, we designed and fabricated a hybrid superhydrophobic-hydrophilic surface. An array of hydrophilic needles, thermally connected to a heat sink, was forced through a robust superhydrophobic polymer film. Condensation occurs preferentially on the needle surface due to differences in wettability and temperature. As the droplet grows, the liquid drop on the needle remains in the Cassie state and does not wet the underlying superhydrophobic surface. The water collection rate on this surface was studied using different surface tilt angles, needle array pitch values, and needle heights. Water condensation rates on the hybrid surface were shown to be 4 times greater than for a planar copper surface and twice as large for silanized silicon or superhydrophobic surfaces without hydrophilic features. A convection-conduction heat transfer model was developed; predicted water condensation rates were in good agreement with experimental observations. This type of hybrid superhydrophobic-hydrophilic surface with a larger array of needles is low-cost, robust, and scalable and so could be used for heat

  8. Dual-band frequency selective surface with large band separation and stable performance

    International Nuclear Information System (INIS)

    Zhou Hang; Qu Shao-Bo; Lin Bao-Qin; Wang Jia-Fu; Ma Hua; Zhang Jie-Qiu; Peng Wei-Dong; Bai Peng; Wang Xu-Hua; Xu Zhuo

    2012-01-01

    A new technique of designing a dual-band frequency selective surface with large band separation is presented. This technique is based on a delicately designed topology of L- and Ku-band microwave filters. The two band-pass responses are generated by a capacitively-loaded square-loop frequency selective surface and an aperture-coupled frequency selective surface, respectively. A Faraday cage is located between the two frequency selective surface structures to eliminate undesired couplings. Based on this technique, a dual-band frequency selective surface with large band separation is designed, which possesses large band separation, high selectivity, and stable performance under various incident angles and different polarizations. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  9. A high surface area Zr(IV)-based metal–organic framework showing stepwise gas adsorption and selective dye uptake

    Energy Technology Data Exchange (ETDEWEB)

    Lv, Xiu-Liang [Beijing Key Laboratory for Green Catalysis and Separation, Department of Chemistry and Chemical Engineering, Beijing University of Technology, Beijing 100124 (China); Tong, Minman; Huang, Hongliang [College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Wang, Bin; Gan, Lei [Beijing Key Laboratory for Green Catalysis and Separation, Department of Chemistry and Chemical Engineering, Beijing University of Technology, Beijing 100124 (China); Yang, Qingyuan [College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Zhong, Chongli [College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); State Key Laboratory of Organic–Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Li, Jian-Rong, E-mail: jrli@bjut.edu.cn [Beijing Key Laboratory for Green Catalysis and Separation, Department of Chemistry and Chemical Engineering, Beijing University of Technology, Beijing 100124 (China); State Key Laboratory of Organic–Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China)

    2015-03-15

    Exploitation of new metal–organic framework (MOF) materials with high surface areas has been attracting great attention in related research communities due to their broad potential applications. In this work, a new Zr(IV)-based MOF, [Zr{sub 6}O{sub 4}(OH){sub 4}(eddb){sub 6}] (BUT-30, H{sub 2}eddb=4,4′-(ethyne-1,2-diyl)dibenzoic acid) has been solvothermally synthesized, characterized, and explored for gases and dyes adsorptions. Single-crystal X-ray diffraction analysis demonstrates a three-dimensional cubic framework structure of this MOF, in which each Zr{sub 6}O{sub 4}(OH){sub 4} building unit is linked by 12 linear eddb ligands. BUT-30 has been found stable up to 400 °C and has a Brunauer–Emmett–Teller (BET) surface area as high as 3940.6 m{sup 2} g{sup −1} (based on the N{sub 2} adsorption at 77 K) and total pore volume of 1.55 cm{sup 3} g{sup −1}. It is more interesting that this MOF exhibits stepwise adsorption behaviors for Ar, N{sub 2}, and CO{sub 2} at low temperatures, and selective uptakes towards different ionic dyes. - Graphical abstract: A new Zr(IV)-based MOF with high surface area has been synthesized and structurally characterized, which shows stepwise gas adsorption at low temperature and selective dye uptake from solution. - Highlights: • A new Zr-based MOF was synthesized and structurally characterized. • This MOF shows a higher surface area compared with its analogous UiO-67 and 68. • This MOF shows a rare stepwise adsorption towards light gases at low temperature. • This MOF performs selective uptakes towards cationic dyes over anionic ones. • Using triple-bond spacer is confirmed feasible in enhancing MOF surface areas.

  10. Stable functionalization of germanium surface and its application in biomolecules immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Qi [State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, No.865, Changning Road, Shanghai 200050 (China); University of Chinese Academy of Sciences, No.19A, Yuquan Road, Beijing 100049 (China); Xu, Baojian [State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, No.865, Changning Road, Shanghai 200050 (China); Ye, Lin [Sate Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, No.865, Changning Road, Shanghai 200050 (China); University of Chinese Academy of Sciences, No.19A, Yuquan Road, Beijing 100049 (China); Tang, Teng; Huang, Shanluo; Du, Xiaowei [State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, No.865, Changning Road, Shanghai 200050 (China); University of Chinese Academy of Sciences, No.19A, Yuquan Road, Beijing 100049 (China); Bian, Xiaojun; Zhang, Jishen [State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, No.865, Changning Road, Shanghai 200050 (China); Di, Zengfeng, E-mail: zfdi@mail.sim.ac.cn [Sate Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, No.865, Changning Road, Shanghai 200050 (China); Jin, Qinghui [State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, No.865, Changning Road, Shanghai 200050 (China); Zhao, Jianlong, E-mail: jlzhao@mail.sim.ac.cn [State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, No.865, Changning Road, Shanghai 200050 (China)

    2014-10-15

    Highlights: • An effective method to immobilize biomolecules on the functionalized Ge surface. • The surface of Ge was functionalized with 11-Mercaptoundecanoic acid (11-MUA). • Stable and uniform SAMs was obtained on Ge surface after 11-MUA treatment. • The functionalized Ge was employed as substrate for protein immobilization. • Paving the way of Ge for further applications in bioelectronics field. - Abstract: As a typical semiconductor material, germanium (Ge) has the potential to be utilized in microelectronics and bioelectronics. Herein, we present a simple and effective method to immobilize biomolecules on the surface of functionalized Ge. The surface oxide of Ge was removed with the pretreatment of hydrochloric acid and the Cl-terminated Ge reacted with 11-Mercaptoundecanoic acid (11-MUA). The surface of Ge was coated with 11-MUA self-assembled monolayers (SAMs) due to the bonding reaction between the sulfhydryl group of 11-MUA and Cl-terminated Ge. Furthermore, typical biomolecule, a green fluorescent protein was chosen to be immobilized on the surface of the functionalized Ge. Contact angle analysis, atomic force microscopy and X-ray photoelectron spectroscopy were used to study the characteristics including wettability, stability, roughness and component of the functionalized Ge, respectively. Fluorescence microscopy was utilized to indicate the efficiency of protein immobilization on the surface of the functionalized Ge. With these studies, stable and uniform functionalized monolayer was obtained on the surface of Ge after 11-MUA treatment and the functionalized Ge was effectively applied in protein immobilization. Furthermore, this study may pave the way for further applications such as the integration of bioelectronics and biosensors with the attractive semiconductor material-Ge in future work.

  11. Electromyographic activity and 6RM strength in bench press on stable and unstable surfaces.

    Science.gov (United States)

    Saeterbakken, Atle H; Fimland, Marius S

    2013-04-01

    The purpose of the study was to compare 6-repetition maximum (6RM) loads and muscle activity in bench press on 3 surfaces, namely, stable bench, balance cushion, and Swiss ball. Sixteen healthy, resistance-trained men (age 22.5 ± 2.0 years, stature 1.82 ± 6.6 m, and body mass 82.0 ± 7.8 kg) volunteered for 3 habituation/strength testing sessions and 1 experimental session. In randomized order on the 3 surfaces, 6RM strength and electromyographic activity of pectoralis major, deltoid anterior, biceps brachii, triceps brachii, rectus abdominis, oblique external and erector spinae were assessed. Relative to stable bench, the 6RM strength was approximately 93% for balance cushion (p ≤ 0.001) and approximately 92% for Swiss ball (p = 0.008); the pectoralis major electromyographic (EMG) activity was approximately 90% using the balance cushion (p = 0.080) and approximately 81% using Swiss ball (p = 0.006); the triceps EMG was approximately 79% using the balance cushion (p = 0.028) and approximately 69% using the Swiss ball (p = 0.002). Relative to balance cushion, the EMG activity in pectoralis, triceps, and erector spinae using Swiss ball was approximately 89% (p = 0.016), approximately 88% (p = 0.014) and approximately 80% (p = 0.020), respectively. In rectus abdominis, the EMG activity relative to Swiss ball was approximately 69% using stable bench (p = 0.042) and approximately 65% using the balance cushion (p = 0.046). Similar EMG activities between stable and unstable surfaces were observed for deltoid anterior, biceps brachii, and oblique external. In conclusion, stable bench press had greater 6RM strength and triceps and pectoralis EMG activity compared with the unstable surfaces. These findings have implications for athletic training and rehabilitation, because they demonstrate an inferior effect of unstable surfaces on muscle activation of prime movers and strength in bench press. If an unstable surface in bench press is desirable, a balance cushion should

  12. Effect of surface texture and structure on the development of stable fluvial armors

    Science.gov (United States)

    Bertin, Stephane; Friedrich, Heide

    2018-04-01

    Stable fluvial armors are found in river systems under conditions of partial sediment transport and limited sediment supply, a common occurrence in nature. Stable armoring is also readily recreated in experimental flumes. Initially, this bed stabilizing phenomenon was examined for different flow discharges and solely related to surface coarsening and bedload transport reduction. The models developed suggest a specific armor composition (i.e., texture) dependent on the parent bed material and formative discharge. Following developments in topographic remote sensing, recent research suggests that armor structure is an important control on bed stability and roughness. In this paper, replicated flume runs during which digital elevation models (DEMs) were collected from both exposed and flooded gravel beds are used to interpret armoring manifestations and to assess their replicability. A range of methodologies was used for the analysis, providing information on (i) surface grain size and orientation, (ii) bed-elevation distributions, (iii) the spatial coherence of the elevations at the grain-scale, (iv) surface slope and aspect, (v) grain imbrication and (vi) the spatial variability in DEM properties. The bed-surface topography was found to be more responsive than bed-material size to changes in flow strength. Our experimental results also provide convincing evidence that gravel-beds' response to water-work during parallel degradation is unique (i.e., replicable) given the formative parameters. Based on this finding, relationships between the armors' properties and formative parameters are proposed, and are supported by adding extensive data from previous research.

  13. Electrostatic powder spraying process for the fabrication of stable superhydrophobic surfaces

    Science.gov (United States)

    Gu, Guotuan; Tian, Yuping; Li, Zhantie; Lu, Dongfang

    2011-03-01

    Nano-sized Al2O3 particles were modified by heptadecafluorodecyl trimethoxysilane and 2,3-epoxy propoxy propyl trimethoxysilicane to make it both hydrophobic and reactive. The reactive nano-particles were mixed with polyester resin containing curing agents and electrostatic sprayed on stainless steel substrates to obtain stable superhydrophobic coatings after curing. The water contact angle (WCA) on the hybrid coating is influenced by the content of Al2O3 particles in the coating. As the Al2O3 concentration in the coating was increased from 0% to 8%, WCA increased from 68° to 165°. Surface topography of the coatings was examined using scanning electron microscopy (SEM). Nano-particles covered on the coating surface formed continuous film with greatly enhanced roughness, which was found to be responsible for the superhydrophobicity. The method is simple and cost effective and can be used for preparing self-cleaning superhydrophobic coating on large areas.

  14. Electrostatic powder spraying process for the fabrication of stable superhydrophobic surfaces

    International Nuclear Information System (INIS)

    Gu Guotuan; Tian Yuping; Li Zhantie; Lu Dongfang

    2011-01-01

    Nano-sized Al 2 O 3 particles were modified by heptadecafluorodecyl trimethoxysilane and 2,3-epoxy propoxy propyl trimethoxysilicane to make it both hydrophobic and reactive. The reactive nano-particles were mixed with polyester resin containing curing agents and electrostatic sprayed on stainless steel substrates to obtain stable superhydrophobic coatings after curing. The water contact angle (WCA) on the hybrid coating is influenced by the content of Al 2 O 3 particles in the coating. As the Al 2 O 3 concentration in the coating was increased from 0% to 8%, WCA increased from 68 o to 165 o . Surface topography of the coatings was examined using scanning electron microscopy (SEM). Nano-particles covered on the coating surface formed continuous film with greatly enhanced roughness, which was found to be responsible for the superhydrophobicity. The method is simple and cost effective and can be used for preparing self-cleaning superhydrophobic coating on large areas.

  15. Fabricating a Homogeneously Alloyed AuAg Shell on Au Nanorods to Achieve Strong, Stable, and Tunable Surface Plasmon Resonances

    KAUST Repository

    Huang, Jianfeng; Zhu, Yihan; Liu, Changxu; Zhao, Yunfeng; Liu, Zhaohui; Hedhili, Mohamed N.; Fratalocchi, Andrea; Han, Yu

    2015-01-01

    Colloidal metal nanocrystals with strong, stable, and tunable localized surface plasmon resonances (SPRs) can be useful in a corrosive environment for many applications including field-enhanced spectroscopies, plasmon-mediated catalysis, etc. Here

  16. Lithium inclusion in indium metal-organic frameworks showing increased surface area and hydrogen adsorption

    Directory of Open Access Journals (Sweden)

    Mathieu Bosch

    2014-12-01

    Full Text Available Investigation of counterion exchange in two anionic In-Metal-Organic Frameworks (In-MOFs showed that partial replacement of disordered ammonium cations was achieved through the pre-synthetic addition of LiOH to the reaction mixture. This resulted in a surface area increase of over 1600% in {Li [In(1,3 − BDC2]}n and enhancement of the H2 uptake of approximately 275% at 80 000 Pa at 77 K. This method resulted in frameworks with permanent lithium content after repeated solvent exchange as confirmed by inductively coupled plasma mass spectrometry. Lithium counterion replacement appears to increase porosity after activation through replacement of bulkier, softer counterions and demonstrates tuning of pore size and properties in MOFs.

  17. Current Options for Measuring the Surface Temperature of Dairy Cattle in a Stable Technology: Review

    Directory of Open Access Journals (Sweden)

    Kateřina Švejdová

    2016-05-01

    Full Text Available Regular measurement of the body surface temperature can help to assess the health status of animals. There are many technological possibilities of contactless temperature measurement of body surface. The important thing is to find the right part of the body whose temperature will point to the first possible symptoms and immediately react to the first signs of the disease. Disagreements about how to measure body surface temperature and accuracy of the method can occur when different measures are used. We review work showing possibilities of contactless surface temperature measurements using 1 thermography, 2 electronic transponders and 3 other possibilities of measuring the body surface temperature of dairy cattle. For example, when we scan the surface temperature with the thermal imager there can operate in individual animals confounding factors such as the nature or degree of muscular coat, which may significantly affect the results.

  18. Preparation of Stable Superhydrophobic Coatings on Wood Substrate Surfaces via Mussel-Inspired Polydopamine and Electroless Deposition Methods

    Directory of Open Access Journals (Sweden)

    Kaili Wang

    2017-06-01

    Full Text Available Mussel-inspired polydopamine (PDA chemistry and electroless deposition approaches were used to prepare stable superhydrophobic coatings on wood surfaces. The as-formed PDA coating on a wood surface exhibited a hierarchical micro/nano roughness structure, and functioned as an “adhesive layer” between the substrate and a metallic film by the metal chelating ability of the catechol moieties on PDA, allowing for the formation of a well-developed micro/nanostructure hierarchical roughness. Additionally, the coating acted as a stable bridge between the substrate and hydrophobic groups. The morphology and chemical components of the prepared superhydrophobic wood surfaces were characterized by scanning electron microscopy (SEM, Fourier transform infrared (FT-IR spectroscopy, and X-ray photoelectron spectroscopy (XPS. The PDA and octadecylamine (OA modified surface showed excellent superhydrophobicity with a water contact angle (CA of about 153° and a rolling angle (RA of about 9°. The CA further increased to about 157° and RA reduced to about 5° with the Cu metallization. The superhydrophobic material exhibited outstanding stability in harsh conditions including ultraviolet aging, ultrasonic washing, strong acid-base and organic solvent immersion, and high-temperature water boiling. The results suggested that the PDA/OA layers were good enough to confer robust, degradation-resistant superhydrophobicity on wood substrates. The Cu metallization was likely unnecessary to provide significant improvements in superhydrophobic property. However, due to the amazing adhesive capacity of PDA, the electroless deposition technique may allow for a wide range of potential applications in biomimetic materials.

  19. TGP, an extremely stable, non-aggregating fluorescent protein created by structure-guided surface engineering

    Science.gov (United States)

    Close, Devin W.; Don Paul, Craig; Langan, Patricia S.; Wilce, Matthew C.J.; Traore, Daouda A.K.; Halfmann, Randal; Rocha, Reginaldo C.; Waldo, Geoffery S.; Payne, Riley J.; Rucker, Joseph B.; Prescott, Mark; Bradbury, Andrew R.M.

    2014-01-01

    In this paper we describe the engineering and X-ray crystal structure of Thermal Green Protein (TGP), an extremely stable, highly soluble, non-aggregating green fluorescent protein. TGP is a soluble variant of the fluorescent protein eCGP123, which despite being highly stable, has proven to be aggregation-prone. The X-ray crystal structure of eCGP123, also determined within the context of this paper, was used to carry out rational surface engineering to improve its solubility, leading to TGP. The approach involved simultaneously eliminating crystal lattice contacts while increasing the overall negative charge of the protein. Despite intentional disruption of lattice contacts and introduction of high entropy glutamate side chains, TGP crystallized readily in a number of different conditions and the X-ray crystal structure of TGP was determined to 1.9 Å resolution. The structural reasons for the enhanced stability of TGP and eCGP123 are discussed. We demonstrate the utility of using TGP as a fusion partner in various assays and significantly, in amyloid assays in which the standard fluorescent protein, EGFP, is undesirable because of aberrant oligomerization. PMID:25287913

  20. Thermal green protein, an extremely stable, nonaggregating fluorescent protein created by structure-guided surface engineering.

    Science.gov (United States)

    Close, Devin W; Paul, Craig Don; Langan, Patricia S; Wilce, Matthew C J; Traore, Daouda A K; Halfmann, Randal; Rocha, Reginaldo C; Waldo, Geoffery S; Payne, Riley J; Rucker, Joseph B; Prescott, Mark; Bradbury, Andrew R M

    2015-07-01

    In this article, we describe the engineering and X-ray crystal structure of Thermal Green Protein (TGP), an extremely stable, highly soluble, non-aggregating green fluorescent protein. TGP is a soluble variant of the fluorescent protein eCGP123, which despite being highly stable, has proven to be aggregation-prone. The X-ray crystal structure of eCGP123, also determined within the context of this paper, was used to carry out rational surface engineering to improve its solubility, leading to TGP. The approach involved simultaneously eliminating crystal lattice contacts while increasing the overall negative charge of the protein. Despite intentional disruption of lattice contacts and introduction of high entropy glutamate side chains, TGP crystallized readily in a number of different conditions and the X-ray crystal structure of TGP was determined to 1.9 Å resolution. The structural reasons for the enhanced stability of TGP and eCGP123 are discussed. We demonstrate the utility of using TGP as a fusion partner in various assays and significantly, in amyloid assays in which the standard fluorescent protein, EGFP, is undesirable because of aberrant oligomerization. © 2014 Wiley Periodicals, Inc.

  1. Leishmania-specific surface antigens show sub-genus sequence variation and immune recognition.

    Directory of Open Access Journals (Sweden)

    Daniel P Depledge

    2010-09-01

    Full Text Available A family of hydrophilic acylated surface (HASP proteins, containing extensive and variant amino acid repeats, is expressed at the plasma membrane in infective extracellular (metacyclic and intracellular (amastigote stages of Old World Leishmania species. While HASPs are antigenic in the host and can induce protective immune responses, the biological functions of these Leishmania-specific proteins remain unresolved. Previous genome analysis has suggested that parasites of the sub-genus Leishmania (Viannia have lost HASP genes from their genomes.We have used molecular and cellular methods to analyse HASP expression in New World Leishmania mexicana complex species and show that, unlike in L. major, these proteins are expressed predominantly following differentiation into amastigotes within macrophages. Further genome analysis has revealed that the L. (Viannia species, L. (V. braziliensis, does express HASP-like proteins of low amino acid similarity but with similar biochemical characteristics, from genes present on a region of chromosome 23 that is syntenic with the HASP/SHERP locus in Old World Leishmania species and the L. (L. mexicana complex. A related gene is also present in Leptomonas seymouri and this may represent the ancestral copy of these Leishmania-genus specific sequences. The L. braziliensis HASP-like proteins (named the orthologous (o HASPs are predominantly expressed on the plasma membrane in amastigotes and are recognised by immune sera taken from 4 out of 6 leishmaniasis patients tested in an endemic region of Brazil. Analysis of the repetitive domains of the oHASPs has shown considerable genetic variation in parasite isolates taken from the same patients, suggesting that antigenic change may play a role in immune recognition of this protein family.These findings confirm that antigenic hydrophilic acylated proteins are expressed from genes in the same chromosomal region in species across the genus Leishmania. These proteins are

  2. Effect of Built-Up Edge Formation during Stable State of Wear in AISI 304 Stainless Steel on Machining Performance and Surface Integrity of the Machined Part.

    Science.gov (United States)

    Ahmed, Yassmin Seid; Fox-Rabinovich, German; Paiva, Jose Mario; Wagg, Terry; Veldhuis, Stephen Clarence

    2017-10-25

    During machining of stainless steels at low cutting -speeds, workpiece material tends to adhere to the cutting tool at the tool-chip interface, forming built-up edge (BUE). BUE has a great importance in machining processes; it can significantly modify the phenomenon in the cutting zone, directly affecting the workpiece surface integrity, cutting tool forces, and chip formation. The American Iron and Steel Institute (AISI) 304 stainless steel has a high tendency to form an unstable BUE, leading to deterioration of the surface quality. Therefore, it is necessary to understand the nature of the surface integrity induced during machining operations. Although many reports have been published on the effect of tool wear during machining of AISI 304 stainless steel on surface integrity, studies on the influence of the BUE phenomenon in the stable state of wear have not been investigated so far. The main goal of the present work is to investigate the close link between the BUE formation, surface integrity and cutting forces in the stable sate of wear for uncoated cutting tool during the cutting tests of AISI 304 stainless steel. The cutting parameters were chosen to induce BUE formation during machining. X-ray diffraction (XRD) method was used for measuring superficial residual stresses of the machined surface through the stable state of wear in the cutting and feed directions. In addition, surface roughness of the machined surface was investigated using the Alicona microscope and Scanning Electron Microscopy (SEM) was used to reveal the surface distortions created during the cutting process, combined with chip undersurface analyses. The investigated BUE formation during the stable state of wear showed that the BUE can cause a significant improvement in the surface integrity and cutting forces. Moreover, it can be used to compensate for tool wear through changing the tool geometry, leading to the protection of the cutting tool from wear.

  3. Mapping Precipitation Patterns from the Stable Isotopic Composition of Surface Waters: Olympic Peninsula, Washington State

    Science.gov (United States)

    Anders, A. M.; Brandon, M. T.

    2008-12-01

    Available data indicate that large and persistent precipitation gradients are tied to topography at scales down to a few kilometers, but precipitation patterns in the majority of mountain ranges are poorly constrained at scales less than tens of kilometers. A lack of knowledge of precipitation patterns hampers efforts to understand the processes of orographic precipitation and identify the relationships between geomorphic evolution and climate. A new method for mapping precipitation using the stable isotopic composition of surface waters is tested in the Olympic Mountains of Washington State. Measured δD and δ18O of 97 samples of surface water are linearly related and nearly inseparable from the global meteoric water line. A linear orographic precipitation model extended to include in effects of isotopic fractionation via Rayleigh distillation predicts precipitation patterns and isotopic composition of surface water. Seven parameters relating to the climate and isotopic composition of source water are used. A constrained random search identifies the best-fitting parameter set. Confidence intervals for parameter values are defined and precipitation patterns are determined. Average errors for the best-fitting model are 4.8 permil in δD. The difference between the best fitting model and other models within the 95% confidence interval was less than 20%. An independent high-resolution precipitation climatology documents precipitation gradients similar in shape and magnitude to the model derived from surface water isotopic composition. This technique could be extended to other mountain ranges, providing an economical and fast assessment of precipitation patterns requiring minimal field work.

  4. Stable isotope probing of acetate fed anaerobic batch incubations shows a partial resistance of acetoclastic methanogenesis catalyzed by Methanosarcina to sudden increase of ammonia level.

    Science.gov (United States)

    Hao, Liping; Lü, Fan; Mazéas, Laurent; Desmond-Le Quéméner, Elie; Madigou, Céline; Guenne, Angéline; Shao, Liming; Bouchez, Théodore; He, Pinjing

    2015-02-01

    Ammonia inhibition represents a major operational issue for anaerobic digestion. In order to refine our understanding of the terminal catabolic steps in thermophilic anaerobic digestion under ammonia stress, we studied batch thermophilic acetate fed experiments at low (0.26 g L(-1)) and high (7.00 g L(-1)) Total Ammonia Nitrogen concentrations (TAN). Although methane production started immediately for all incubations and resulted in methane yields close to stoichiometric expectations, a 62-72% decrease of methanogenic rate was observed throughout the incubation at 7.00 g L(-1) of TAN compared to 0.26 g L(-1). Stable Isotope Probing analysis of active microbial communities in (13)C-acetate fed experiments coupled to automated ribosomal intergenic spacer analysis and 16S rDNA pyrotag sequencing confirmed that microbial communities were similar for both TAN conditions. At both TAN levels, the (13)C-labeled bacterial community was mainly affiliated to Clostridia-relatives, with OPB54 bacteria being the most abundant sequence in the heavy DNA 16S rDNA pyrotag library. Sequences closely related to Methanosarcina thermophila were also abundantly retrieved in the heavy DNA fractions, showing that this methanogen was still actively assimilating labeled carbon from acetate at free ammonia nitrogen concentrations up to 916 mg L(-1). Stable isotopic signature analysis of biogas, measured in unlabeled acetate fed experiments that were conducted in parallel, confirmed that acetoclastic methanogenic pathway was dominant at both ammonia concentrations. Our work demonstrates that, besides the syntrophic acetate oxidation pathway, acetoclastic methanogenesis catalyzed by Methanosarcina can also play a major role in methane production at high ammonia levels. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Classifying Multi-Model Wheat Yield Impact Response Surfaces Showing Sensitivity to Temperature and Precipitation Change

    Science.gov (United States)

    Fronzek, Stefan; Pirttioja, Nina; Carter, Timothy R.; Bindi, Marco; Hoffmann, Holger; Palosuo, Taru; Ruiz-Ramos, Margarita; Tao, Fulu; Trnka, Miroslav; Acutis, Marco; hide

    2017-01-01

    Crop growth simulation models can differ greatly in their treatment of key processes and hence in their response to environmental conditions. Here, we used an ensemble of 26 process-based wheat models applied at sites across a European transect to compare their sensitivity to changes in temperature (minus 2 to plus 9 degrees Centigrade) and precipitation (minus 50 to plus 50 percent). Model results were analysed by plotting them as impact response surfaces (IRSs), classifying the IRS patterns of individual model simulations, describing these classes and analysing factors that may explain the major differences in model responses. The model ensemble was used to simulate yields of winter and spring wheat at four sites in Finland, Germany and Spain. Results were plotted as IRSs that show changes in yields relative to the baseline with respect to temperature and precipitation. IRSs of 30-year means and selected extreme years were classified using two approaches describing their pattern. The expert diagnostic approach (EDA) combines two aspects of IRS patterns: location of the maximum yield (nine classes) and strength of the yield response with respect to climate (four classes), resulting in a total of 36 combined classes defined using criteria pre-specified by experts. The statistical diagnostic approach (SDA) groups IRSs by comparing their pattern and magnitude, without attempting to interpret these features. It applies a hierarchical clustering method, grouping response patterns using a distance metric that combines the spatial correlation and Euclidian distance between IRS pairs. The two approaches were used to investigate whether different patterns of yield response could be related to different properties of the crop models, specifically their genealogy, calibration and process description. Although no single model property across a large model ensemble was found to explain the integrated yield response to temperature and precipitation perturbations, the

  6. Realization of Multi-Stable Ground States in a Nematic Liquid Crystal by Surface and Electric Field Modification

    Science.gov (United States)

    Gwag, Jin Seog; Kim, Young-Ki; Lee, Chang Hoon; Kim, Jae-Hoon

    2015-06-01

    Owing to the significant price drop of liquid crystal displays (LCDs) and the efforts to save natural resources, LCDs are even replacing paper to display static images such as price tags and advertising boards. Because of a growing market demand on such devices, the LCD that can be of numerous surface alignments of directors as its ground state, the so-called multi-stable LCD, comes into the limelight due to the great potential for low power consumption. However, the multi-stable LCD with industrial feasibility has not yet been successfully performed. In this paper, we propose a simple and novel configuration for the multi-stable LCD. We demonstrate experimentally and theoretically that a battery of stable surface alignments can be achieved by the field-induced surface dragging effect on an aligning layer with a weak surface anchoring. The simplicity and stability of the proposed system suggest that it is suitable for the multi-stable LCDs to display static images with low power consumption and thus opens applications in various fields.

  7. Characterizing interactions between surface water and groundwater in the Jialu River basin using major ion chemistry and stable isotopes

    Directory of Open Access Journals (Sweden)

    L. Yang

    2012-11-01

    Full Text Available The Jialu River, a secondary tributary of the Huaihe River, has been severely contaminated from major contaminant sources, such as a number of untreated or lightly treated sewage waste in some cities. Groundwater along the river is not an isolated component of the hydrologic system, but is instead connected with the surface water. This study aims to investigate temporal and spatial variations in water chemistry affected by humans and to characterize the relationships between surface water (e.g. reservoirs, lakes and rivers and groundwater near the river in the shallow Quaternary aquifer. Concentration of Cl in north Zhengzhou City increased prominently due to the discharge of a large amount of domestic water. Nitrate and potassium show maximum concentrations in groundwater in Fugou County. These high levels can be attributed to the use of a large quantity of fertilizer over this region. Most surface water appeared to be continuously recharged from the surrounding groundwater (regional wells based on comparison surface water with groundwater levels, stable-isotopes and major ion signatures. However, the groundwater of a transitional well (location SY3 seemed to be recharged by river water via bank infiltration in September 2010. Fractional contributions of river water to the groundwater were calculated based on isotopic and chemical data using a mass-balance approach. Results show that the groundwater was approximately composed of 60–70% river water. These findings should be useful for a better understanding of hydrogeological processes at the river-aquifer interface and ultimately benefit water management in the future.

  8. Stable Weyl points, trivial surface states, and particle-hole compensation in WP2

    Science.gov (United States)

    Razzoli, E.; Zwartsenberg, B.; Michiardi, M.; Boschini, F.; Day, R. P.; Elfimov, I. S.; Denlinger, J. D.; Süss, V.; Felser, C.; Damascelli, A.

    2018-05-01

    A possible connection between extremely large magnetoresistance and the presence of Weyl points has garnered much attention in the study of topological semimetals. Exploration of these concepts in transition-metal diphosphides WP2 has been complicated by conflicting experimental reports. Here we combine angle-resolved photoemission spectroscopy (ARPES) and density functional theory (DFT) calculations to disentangle surface and bulk contributions to the ARPES intensity, the superposition of which has plagued the determination of the band structure in WP2. Our results show that while the hole- and electronlike Fermi surface sheets originating from surface states have different areas, the bulk-band structure of WP2 is electron-hole compensated in agreement with DFT. Furthermore, the ARPES band structure is compatible with the presence of at least four temperature-independent Weyl points, confirming the topological nature of WP2 and its stability against lattice distortions.

  9. Interactions between surface waters in King George Island, Antarctica - a stable isotope perspective

    Science.gov (United States)

    Perşoiu, Aurel; Bădăluşă, Carmen

    2017-04-01

    In this paper we present a first study of the isotopic composition of surface waters in the southern peninsulas (Barton, Fildes, Weaver and Potter) of King George Island, Antarctica. We have collected > 200 samples of snow and snowmelt, water (lake, river and spring), ice (glacier ice and permafrost) from the four peninsulas in February 2016 and analyzed them for their oxygen and hydrogen stable isotopic composition. Samples from lake water (50+) indicate a clear west-east depletion trend, suggesting a rain-out process as air masses are moving westward (and are progressively depleted in heavy isotopes) from their origin in the Drake Passage. In both Fildes and Barton Peninsulas, permafrost samples have the heaviest isotopic composition, most probably due to preferential incorporation of heavy isotopes in the ice during freezing (and no fractionation during melting). As permafrost melts, the resulting water mixes with isotopically lighter infiltrated snowmelt, and thus the groundwater has a lower isotopic composition. Further, lake and river (the later fed by lakes) water has the lightest isotopic composition, being derived mostly from the melting of light snow and glacier ice. It seems feasible to separate isotopically water in lakes/rivers (largely fed by melting multi-year glaciers and snow) and water from melting of snow/ground ice This preliminary study suggests that it is possible to separate various water sources in the southern peninsulas of King George Island, and this separation could be used to study permafrost degradation, as well as feeding and migration patterns in the bird fauna, with implications for protection purposes. Acknowledgments. The National Institute of Research and Development for Biological Sciences (Bucharest, Romania) and the Korean polar institute financially supported fieldwork in King George Island. We thank the personal at King Sejong (South Korea), Belingshaussen (Russia) and Carlini (Argentina) stations in King George Island for

  10. Lentivirus display: stable expression of human antibodies on the surface of human cells and virus particles.

    Directory of Open Access Journals (Sweden)

    Ran Taube

    Full Text Available BACKGROUND: Isolation of human antibodies using current display technologies can be limited by constraints on protein expression, folding and post-translational modifications. Here we describe a discovery platform that utilizes self-inactivating (SIN lentiviral vectors for the surface display of high-affinity single-chain variable region (scFv antibody fragments on human cells and lentivirus particles. METHODOLOGY/PRINCIPAL FINDINGS: Bivalent scFvFc human antibodies were fused in frame with different transmembrane (TM anchoring moieties to allow efficient high-level expression on human cells and the optimal TM was identified. The addition of an eight amino acid HIV-1 gp41 envelope incorporation motif further increased scFvFc expression on human cells and incorporation into lentiviral particles. Both antibody-displaying human cells and virus particles bound antigen specifically. Sulfation of CDR tyrosine residues, a property recently shown to broaden antibody binding affinity and antigen recognition was also demonstrated. High level scFvFc expression and stable integration was achieved in human cells following transduction with IRES containing bicistronic SIN lentivectors encoding ZsGreen when scFvFc fusion proteins were expressed from the first cassette. Up to 10(6-fold enrichment of antibody expressing cells was achieved with one round of antigen coupled magnetic bead pre-selection followed by FACS sorting. Finally, the scFvFc displaying human cells could be used directly in functional biological screens with remarkable sensitivity. CONCLUSIONS/SIGNIFICANCE: This antibody display platform will complement existing technologies by virtue of providing properties unique to lentiviruses and antibody expression in human cells, which, in turn, may aid the discovery of novel therapeutic human mAbs.

  11. Comparison of the effects of an eight-week push-up program using stable versus unstable surfaces.

    Science.gov (United States)

    Chulvi-Medrano, Iván; Martínez-Ballester, Esteban; Masiá-Tortosa, Laura

    2012-12-01

    Recently, the trend among physical training and rehabilitation professionals is the use of resistance exercise on unstable equipment in order to increase the effort of the agonist and stabilizing muscles. It is unknown if performing exercises on unstable surfaces provides a greater training stimulus as compared to training on a stable training surface. Therefore, the purpose of this research was to compare the effect that push-up training on stable and unstable surfaces had on strength performance in healthy young men. Thirty subjects with experience in resistance training participated in push-up training two days per week for eight weeks on one of three different surfaces: the floor (Tp), the T-Bow® (TBp) or the BOSU® (Bp). Strength, as measured by one repetition maximum (1-RM) and muscle endurance, as measured by number of pushups performed did not improve significantly (p>0.05) for any of the intervention groups. The addition of unstable surfaces in push-up training does not provide greater improvement in muscular strength and endurance than push up training performed on a stable surface in young men. 3b.

  12. Novel Metal-Sulfur-Based Air-Stable Passivation of GaAs with Very Low Surface State Densities

    Energy Technology Data Exchange (ETDEWEB)

    Ashby, Carol I.H.; Baca, Albert G.; Chang, P.-C; Hafich, M.J.; Hammons, B.E.; Zavadil, Kevin R.

    1999-08-09

    A new air-stable electronic surface passivation for GaAs and other III-V compound semiconductors that employs sulfur and a suitable metal ion, e.g., Zn, and that is robust towards plasma dielectric deposition has been developed. Initial improvements in photoluminescence are twice that of S-only treatments and have been preserved for >11 months with SiO{sub x}N{sub y} dielectric encapsulation. Photoluminescence and X-ray photoelectron spectroscopies indicate that the passivation consists of two major components with one being stable for >2 years in air. This process improves heterojunction bipolar transistor current gain for both large and small area devices.

  13. Minimization of gully erosion on reclaimed surface mines using the stable slope and sediment transport computer model

    International Nuclear Information System (INIS)

    McKenney, R.A.; Gardner, T.G.

    1992-01-01

    Disequilibrium between slope form and hydrologic and erosion processes on reclaimed surface coal mines in the humid temperate northeastern US, can result in gully erosion and sediment loads which are elevated above natural, background values. Initial sheetwash erosion is surpassed by gully erosion on reclamation sites which are not in equilibrium with post-mining hydrology. Long-term stability can be attained by designing a channel profile which is in equilibrium with the increased peak discharges found on reclaimed surface mines. The Stable Slope and Sediment transport model (SSAST) was developed to design stable longitudinal channel profiles for post-mining hydrologic and erosional processes. SSAST is an event based computer model that calculates the stable slope for a channel segment based on the post-mine hydrology and median grain size of a reclaimed surface mine. Peak discharge, which drives post-mine erosion, is calculated from a 10-year, 24-hour storm using the Soil Conservation Service curve number method. Curve number calibrated for Pennsylvania surface mines are used. Reclamation sites are represented by the rectangle of triangle which most closely fits the shape of the site while having the same drainage area and length. Sediment transport and slope stability are calculated using a modified Bagnold's equation with a correction factor for the irregular particle shapes formed during the mining process. Data from three reclaimed Pennsylvania surface mines were used to calibrate and verify SSAST. Analysis indicates that SSAST can predict longitudinal channel profiles for stable reclamation of surface mines in the humid, temperate northeastern US

  14. The O and H stable isotope composition of freshwaters in the British Isles. 2. Surface waters and groundwater

    Directory of Open Access Journals (Sweden)

    W. G. Darling

    2003-01-01

    Full Text Available The utility of stable isotopes as tracers of the water molecule has a long pedigree. The study reported here is part of an attempt to establish a comprehensive isotopic 'baseline' for the British Isles as background data for a range of applications. Part 1 of this study (Darling and Talbot, 2003 considered the isotopic composition of rainfall in Britain and Ireland. The present paper is concerned with the composition of surface waters and groundwater. In isotopic terms, surface waters (other than some upland streams are poorly characterised in the British Isles; their potential variability has yet to be widely used as an aid in hydrological research. In what may be the first study of a major British river, a monthly isotopic record of the upper River Thames during 1998 was obtained. This shows high damping of the isotopic variation compared to that in rainfall over most of the year, though significant fluctuations were seen for the autumn months. Smaller rivers such as the Stour and Darent show a more subdued response to the balance between runoff and baseflow. The relationship between the isotopic composition of rainfall and groundwater is also considered. From a limited database, it appears that whereas Chalk groundwater is a representative mixture of weighted average annual rainfall, for Triassic sandstone groundwater there is a seasonal selection of rainfall biased towards isotopically-depleted winter recharge. This may be primarily the result of physical differences between the infiltration characteristics of rock types, though other factors (vegetation, glacial history could be involved. In the main, however, groundwaters appear to be representative of bulk rainfall within an error band of 0.5‰ δ18O. Contour maps of the δ18O and δ2H content of recent groundwaters in the British Isles show a fundamental SW-NE depletion effect modified by topography. The range of measured values, while much smaller than those for rainfall, still covers

  15. Chemically immobilised carbon nanotubes on silicon: Stable surfaces for aqueous electrochemistry

    International Nuclear Information System (INIS)

    Flavel, Benjamin S.; Garrett, David J.; Lehr, Joshua; Shapter, Joseph G.; Downard, Alison J.

    2010-01-01

    Diazonium ion chemistry has been used to electrochemically graft aminophenyl layers onto p-type silicon (1 0 0) substrates. A condensation reaction was used to immobilise single-walled carbon nanotubes with high carboxylic acid functionality directly to this layer. Electrochemical monitoring of the aminophenyl groups confirmed the formation of an amide linkage between the single-walled carbon nanotubes and the aminophenyl layer. The carbon nanotube electrode showed high stability and good electrochemical performance in aqueous solution. At moderate scan rates the Ru(NH 3 ) 6 +3/+2 couple exhibited quasi-reversible electron transfer kinetics with a standard heterogenous rate constant of 1.2 x 10 -3 cm s -1 at the covalently-linked carbon nanotube surface. The electrode thus combines the advantages of a silicon substrate for easy integration into sophisticated electrical and electronic devices, carbon nanotubes for desirable electrochemical properties, and stability in aqueous medium for future applications in environmental sensing.

  16. Facile Fabrication and Characterization of a PDMS-Derived Candle Soot Coated Stable Biocompatible Superhydrophobic and Superhemophobic Surface.

    Science.gov (United States)

    Iqbal, R; Majhy, B; Sen, A K

    2017-09-13

    We report a simple, inexpensive, rapid, and one-step method for the fabrication of a stable and biocompatible superhydrophobic and superhemophobic surface. The proposed surface comprises candle soot particles embedded in a mixture of PDMS+n-hexane serving as the base material. The mechanism responsible for the superhydrophobic behavior of the surface is explained, and the surface is characterized based on its morphology and elemental composition, wetting properties, mechanical and chemical stability, and biocompatibility. The effect of %n-hexane in PDMS, the thickness of the PDMS+n-hexane layer (in terms of spin coating speed) and sooting time on the wetting property of the surface is studied. The proposed surface exhibits nanoscale surface asperities (average roughness of 187 nm), chemical compositions of soot particles, very high water and blood repellency along with excellent mechanical and chemical stability and excellent biocompatibility against blood sample and biological cells. The water contact angle and roll-off angle is measured as 160° ± 1° and 2°, respectively, and the blood contact angle is found to be 154° ± 1°, which indicates that the surface is superhydrophobic and superhemophobic. The proposed superhydrophobic and superhemophobic surface offers significantly improved (>40%) cell viability as compared to glass and PDMS surfaces.

  17. Synthesis of anti-aggregation silver nanoparticles based on inositol hexakisphosphoric micelles for a stable surface enhanced Raman scattering substrate

    International Nuclear Information System (INIS)

    Wang Na; Yang Haifeng; Zhu Xuan; Zhang Rui; Wang Yao; Huang Guanfeng; Zhang Zongrang

    2009-01-01

    We report a novel method of synthesizing a kind of silver nanoparticles aided by the inositol hexakisphosphoric micelle as a soft template and stabilizer. By controlling the reaction time, UV-vis and TEM observations of the size growth of the nanoparticles are performed. Careful examinations of surface enhanced Raman scattering (SERS) spectra of 2-mercaptopyridine (2-Mpy) on the as-produced silver nanoparticles exhibit very stable and reproducible Raman signals within about 4 months.

  18. Stable, metastable and unstable solutions of a spin-1 Ising system based on the free energy surfaces

    Science.gov (United States)

    Keskİin, Mustafa; Özgan, Şükrü

    1990-04-01

    Stable, metastable and unstable solutions of a spin-1 Ising model with bilinear and biquadratic interactions are found by using the free energy surfaces. The free energy expression is obtained in the lowest approximation of the cluster variation method. All these solutions are shown in the two-dimensional phase space, especially the unstable solutions which in some cases are difficult to illustrate in the two-dimensional phase space, found by Keskin et al. recently.

  19. Chemically immobilised carbon nanotubes on silicon: Stable surfaces for aqueous electrochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Flavel, Benjamin S., E-mail: ben.flavel@flinders.edu.a [Department of Chemistry, University of Canterbury, Private Bag 4800, Christchurch 8140 (New Zealand); School of Chemistry, Physics and Earth Sciences, Flinders University, Sturt Road, Bedford Park, Adelaide, South Australia 5001 (Australia); Garrett, David J.; Lehr, Joshua [Department of Chemistry, University of Canterbury, Private Bag 4800, Christchurch 8140 (New Zealand); MacDiarmid Institute for Advanced Materials and Nanotechnology, Private Bag 4800, Christchurch 8140 (New Zealand); Shapter, Joseph G. [School of Chemistry, Physics and Earth Sciences, Flinders University, Sturt Road, Bedford Park, Adelaide, South Australia 5001 (Australia); Downard, Alison J., E-mail: alison.downard@canterbury.ac.n [Department of Chemistry, University of Canterbury, Private Bag 4800, Christchurch 8140 (New Zealand); MacDiarmid Institute for Advanced Materials and Nanotechnology, Private Bag 4800, Christchurch 8140 (New Zealand)

    2010-04-30

    Diazonium ion chemistry has been used to electrochemically graft aminophenyl layers onto p-type silicon (1 0 0) substrates. A condensation reaction was used to immobilise single-walled carbon nanotubes with high carboxylic acid functionality directly to this layer. Electrochemical monitoring of the aminophenyl groups confirmed the formation of an amide linkage between the single-walled carbon nanotubes and the aminophenyl layer. The carbon nanotube electrode showed high stability and good electrochemical performance in aqueous solution. At moderate scan rates the Ru(NH{sub 3}){sub 6}{sup +3/+2} couple exhibited quasi-reversible electron transfer kinetics with a standard heterogenous rate constant of 1.2 x 10{sup -3} cm s{sup -1} at the covalently-linked carbon nanotube surface. The electrode thus combines the advantages of a silicon substrate for easy integration into sophisticated electrical and electronic devices, carbon nanotubes for desirable electrochemical properties, and stability in aqueous medium for future applications in environmental sensing.

  20. Colloidally stable surface-modified iron oxide nanoparticles: Preparation, characterization and anti-tumor activity

    Energy Technology Data Exchange (ETDEWEB)

    Macková, Hana [Institute of Macromolecular Chemistry, AS CR, Heyrovsky Sq. 2, 162 06 Prague 6 (Czech Republic); Horák, Daniel, E-mail: horak@imc.cas.cz [Institute of Macromolecular Chemistry, AS CR, Heyrovsky Sq. 2, 162 06 Prague 6 (Czech Republic); Donchenko, Georgiy Viktorovich; Andriyaka, Vadim Ivanovich; Palyvoda, Olga Mikhailovna; Chernishov, Vladimir Ivanovich [Palladin Institute of Biochemistry, NASU, 9 Leontovich St., 01601 Kiev (Ukraine); Chekhun, Vasyl Fedorovich; Todor, Igor Nikolaevich [R. E. Kavetsky Institute of Experimental Pathology, Oncology and Radiobiology, NASU, 45 Vasylkivska St., 03022 Kiev (Ukraine); Kuzmenko, Oleksandr Ivanovich [Palladin Institute of Biochemistry, NASU, 9 Leontovich St., 01601 Kiev (Ukraine)

    2015-04-15

    Maghemite (γ-Fe{sub 2}O{sub 3}) nanoparticles were obtained by co-precipitation of Fe(II) and Fe(III) chlorides and subsequent oxidation with sodium hypochlorite and coated with poly(N,N-dimethylacrylamide-co-acrylic acid) [P(DMAAm-AA)]. They were characterized by a range of methods including transmission electron microscopy (TEM), elemental analysis, dynamic light scattering (DLS) and zeta potential measurements. The effect of superparamagnetic P(DMAAm-AA)-γ-Fe{sub 2}O{sub 3} nanoparticles on oxidation of blood lipids, glutathione and proteins in blood serum was detected using 2-thiobarbituric acid and the ThioGlo fluorophore. Finally, mice received magnetic nanoparticles administered per os and the antitumor activity of the particles was tested on Lewis lung carcinoma (LLC) in male mice line C57BL/6 as an experimental in vivo metastatic tumor model; the tumor size was measured and the number of metastases in lungs was determined. Surface-modified γ-Fe{sub 2}O{sub 3} nanoparticles showed higher antitumor and antimetastatic activities than commercial CuFe{sub 2}O{sub 4} particles and the conventional antitumor agent cisplatin. - Highlights: • Maghemite nanoparticles were prepared and characterized. • Poly(N,N-dimethylacrylamide-co-acrylic acid) coating was synthetized. • Blood lipid, glutathione and protein peroxidation/oxidation was determined. • Antitumor effect of coated particles on Lewis lung carcinoma in mice was observed.

  1. Pectins, Hemicelluloses and Celluloses Show Specific Dynamics in the Internal and External Surfaces of Grape Berry Skin During Ripening.

    Science.gov (United States)

    Fasoli, Marianna; Dell'Anna, Rossana; Dal Santo, Silvia; Balestrini, Raffaella; Sanson, Andrea; Pezzotti, Mario; Monti, Francesca; Zenoni, Sara

    2016-06-01

    Grapevine berry skin is a complex structure that contributes to the final size and shape of the fruit and affects its quality traits. The organization of cell wall polysaccharides in situ and their modification during ripening are largely uncharacterized. The polymer structure of Corvina berry skin, its evolution during ripening and related modifying genes were determined by combing mid-infrared micro-spectroscopy and multivariate statistical analysis with transcript profiling and immunohistochemistry. Spectra were acquired in situ using a surface-sensitive technique on internal and external sides of the skin without previous sample pre-treatment, allowing comparison of the related cell wall polymer dynamics. The external surface featured cuticle-related bands; the internal surface showed more adsorbed water. Application of surface-specific normalization revealed the major molecular changes related to hemicelluloses and pectins in the internal surface and to cellulose and pectins in the external surface and that they occur between mid-ripening and full ripening in both sides of the skin. Transcript profiling of cell wall-modifying genes indicated a general suppression of cell wall metabolism during ripening. Genes related to pectin metabolism-a β-galactosidase, a pectin(methyl)esterase and a pectate lyase-and a xyloglucan endotransglucosylase/hydrolase, involved in hemicellulose modification, showed enhanced expression. In agreement with Fourier transform infrared spectroscopy, patterns due to pectin methyl esterification provided new insights into the relationship between pectin modifications and the associated transcript profile during skin ripening. This study proposes an original description of polymer dynamics in grape berries during ripening, highlighting differences between the internal and external sides of the skin. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For

  2. Fabrication of Water Jet Resistant and Thermally Stable Superhydrophobic Surfaces by Spray Coating of Candle Soot Dispersion.

    Science.gov (United States)

    Qahtan, Talal F; Gondal, Mohammed A; Alade, Ibrahim O; Dastageer, Mohammed A

    2017-08-08

    A facile synthesis method for highly stable carbon nanoparticle (CNP) dispersion in acetone by incomplete combustion of paraffin candle flame is presented. The synthesized CNP dispersion is the mixture of graphitic and amorphous carbon nanoparticles of the size range of 20-50 nm and manifested the mesoporosity with an average pore size of 7 nm and a BET surface area of 366 m 2 g -1 . As an application of this material, the carbon nanoparticle dispersion was spray coated (spray-based coating) on a glass surface to fabricate superhydrophobic (water contact angle > 150° and sliding angle fabricated from direct candle flame soot deposition (candle-based coating). This study proved that water jet resistant and thermally stable superhydrophobic surfaces can be easily fabricated by simple spray coating of CNP dispersion gathered from incomplete combustion of paraffin candle flame and this technique can be used for different applications with the potential for the large scale fabrication.

  3. TOPEX/El Nino Watch - Satellite shows El Nino-related Sea Surface Height, Mar, 14, 1998

    Science.gov (United States)

    1998-01-01

    This image of the Pacific Ocean was produced using sea surface height measurements taken by the U.S.-French TOPEX/Poseidon satellite. The image shows sea surface height relative to normal ocean conditions on Mar. 14, 1998 and sea surface height is an indicator of the heat content of the ocean. The image shows that the sea surface height along the central equatorial Pacific has returned to a near normal state. Oceanographers indicate this is a classic pattern, typical of a mature El Nino condition. Remnants of the El Nino warm water pool, shown in red and white, are situated to the north and south of the equator. These sea surface height measurements have provided scientists with a detailed view of how the 1997-98 El Nino's warm pool behaves because the TOPEX/Poseidon satellite measures the changing sea surface height with unprecedented precision. In this image, the white and red areas indicate unusual patterns of heat storage; in the white areas, the sea surface is between 14 and 32 centimeters (6 to 13 inches) above normal; in the red areas, it's about 10 centimeters (4 inches) above normal. The green areas indicate normal conditions, while purple (the western Pacific) means at least 18 centimeters (7 inches) below normal sea level. The El Nino phenomenon is thought to be triggered when the steady westward blowing trade winds weaken and even reverse direction. This change in the winds allows a large mass of warm water (the red and white area) that is normally located near Australia to move eastward along the equator until it reaches the coast of South America. The displacement of so much warm water affects evaporation, where rain clouds form and, consequently, alters the typical atmospheric jet stream patterns around the world. Using satellite imagery, buoy and ship data, and a forecasting model of the ocean-atmosphere system, the National Oceanic and Atmospheric Administration, (NOAA), has continued to issue an advisory indicating the so-called El Nino weather

  4. Fabrication of stable and durable superhydrophobic surface on copper substrates for oil-water separation and ice-over delay.

    Science.gov (United States)

    Guo, Jie; Yang, Fuchao; Guo, Zhiguang

    2016-03-15

    We report a simple and rapid method to fabricate superhydrophobic films on copper substrates via Fe(3+) etching and octadecanethiol (ODT) modification. The etching process can be as short as 5 min and the ODT treatment only takes several seconds. In addition, the whole process is quite flexible in reaction time. The superhydrophobicity of as-prepared surfaces is mechanically durable and chemically stable, which have great performance in oil-water separation and ice-over resistance. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Direct Covalent Grafting of Phytate to Titanium Surfaces through Ti-O-P Bonding Shows Bone Stimulating Surface Properties and Decreased Bacterial Adhesion.

    Science.gov (United States)

    Córdoba, Alba; Hierro-Oliva, Margarita; Pacha-Olivenza, Miguel Ángel; Fernández-Calderón, María Coronada; Perelló, Joan; Isern, Bernat; González-Martín, María Luisa; Monjo, Marta; Ramis, Joana M

    2016-05-11

    Myo-inositol hexaphosphate, also called phytic acid or phytate (IP6), is a natural molecule abundant in vegetable seeds and legumes. Among other functions, IP6 inhibits bone resorption. It is adsorbed on the surface of hydroxyapatite, inhibiting its dissolution and decreasing the progressive loss of bone mass. We present here a method to directly functionalize Ti surfaces covalently with IP6, without using a cross-linker molecule, through the reaction of the phosphate groups of IP6 with the TiO2 layer of Ti substrates. The grafting reaction consisted of an immersion in an IP6 solution to allow the physisorption of the molecules onto the substrate, followed by a heating step to obtain its chemisorption, in an adaptation of the T-Bag method. The reaction was highly dependent on the IP6 solution pH, only achieving a covalent Ti-O-P bond at pH 0. We evaluated two acidic pretreatments of the Ti surface, to increase its hydroxylic content, HNO3 30% and HF 0.2%. The structure of the coated surfaces was characterized by X-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectrometry, and ellipsometry. The stability of the IP6 coating after three months of storage and after sterilization with γ-irradiation was also determined. Then, we evaluated the biological effect of Ti-IP6 surfaces in vitro on MC3T3-E1 osteoblastic cells, showing an osteogenic effect. Finally, the effect of the surfaces on the adhesion and biofilm viability of oral microorganisms S. mutans and S. sanguinis was also studied, and we found that Ti-IP6 surfaces decreased the adhesion of S. sanguinis. A surface that actively improves osseointegration while decreasing the bacterial adhesion could be suitable for use in bone implants.

  6. Oligocene sea water temperatures offshore Wilkes Land (Antarctica) indicate warm and stable glacial-interglacial variation and show no 'late Oligocene warming'

    Science.gov (United States)

    Hartman, Julian; Bijl, Peter; Peterse, Francien; Schouten, Stefan; Salabarnada, Ariadna; Bohaty, Steven; Escutia, Carlota; Brinkhuis, Henk; Sangiorgi, Francesca

    2017-04-01

    At present, warming of the waters below the Antarctic ice shelves is a major contributor to the instability of the Antarctic cryosphere. In order to get insight into future melt behavior of the Antarctic ice sheet, it is important to look at past warm periods that can serve as an analogue for the future. The Oligocene ( 34-23 Ma) is a period within the range of CO2 concentrations predicted by the latest IPCC report for the coming century and is characterized by a very dynamic Antarctic ice sheet, as suggested by benthic δ18O records from ice-distal sites. We suspect that, like today, environmental changes in the Southern Ocean are in part responsible for this dynamicity. To gain more insight into this, we have reconstructed sea water temperatures (SWT) based on Thaumarchaeotal lipids (TEX86) for the Oligocene record obtained from the ice-proximal Site U1356 (Integrated Ocean Drilling Program), offshore Wilkes Land. Part of our record shows a strong coupling between the lithology and SWT, which we attribute to glacial-interglacial variation. Our data shows that both glacial and interglacial temperatures are relatively warm throughout the Oligocene: 14°C and 18°C respectively, which is consistent with previously published estimates based on UK'37 and clumped isotopes for the early Oligocene. Our SST records show only a minor decline between 30 and 24 Ma, and thus show no evidence for a 'late Oligocene warming' as was suggested based on benthic δ18O records from low latitudes. Instead, the discrepancy between our SST trend and the δ18O trend suggests that the late-Oligocene benthic δ18O decrease is likely related to a decline in ice volume. After 24 Ma, however, glacial-interglacial temperature variation appears to increase. In particular, some large temperature drops occur, one of which can be related to the Mi-1 event and a major expansion of the Antarctic ice sheet.

  7. Observation of ferromagnetic ordering in a stable α -Co (OH) 2 phase grown on a Mo S2 surface

    Science.gov (United States)

    Debnath, Anup; Bhattacharya, Shatabda; Saha, Shyamal K.

    2017-12-01

    Because of the potential application of Co (OH) 2 in a magnetic cooling system as a result of its superior magnetocaloric effect many people have investigated magnetic properties of Co (OH) 2 . Unfortunately, most of the works have been carried out on the β -Co (OH) 2 phase due to the fact that the α -Co (OH) 2 phase is very unstable and continuously transformed into the stable β -Co (OH) 2 phase. However, in the present work, using a Mo S2 sheet as a two-dimensional template, we have been able to synthesize a stable α -Co (OH) 2 phase in addition to a β -Co (OH) 2 phase by varying the layer thickness. It is seen that for thinner samples the β phase, while for thicker samples α phase, is grown on the Mo S2 surface. Magnetic measurements are carried out for the samples over the temperature range from 2 to 300 K and it is seen that for the β phase, ferromagnetic ordering with fairly large coercivity (1271 Oe) at 2 K is obtained instead of the usual antiferromagnetism. The most interesting result is the observation of ferromagnetic ordering with a transition temperature (Curie temperature) more than 100 K in the α -Co (OH) 2 phase. Complete saturation in the hysteresis curve under application of very low field having coercivity of ˜162 Oe at 2 K and 60 Oe at 50 K is obtained. A thin stable α -Co (OH) 2 phase grown on Mo S2 surface with very soft ferromagnetic ordering will be very useful as the core material in electromagnets.

  8. Bone cells in birds show exceptional surface area, a characteristic tracing back to saurischian dinosaurs of the late Triassic.

    Directory of Open Access Journals (Sweden)

    John M Rensberger

    Full Text Available Dinosaurs are unique among terrestrial tetrapods in their body sizes, which range from less than 3 gm in hummingbirds to 70,000 kg or more in sauropods. Studies of the microstructure of bone tissue have indicated that large dinosaurs, once believed to be slow growing, attained maturity at rates comparable to or greater than those of large mammals. A number of structural criteria in bone tissue have been used to assess differences in rates of osteogenesis in extinct taxa, including counts of lines of arrested growth and the density of vascular canals.Here, we examine the density of the cytoplasmic surface of bone-producing cells, a feature which may set an upper limit to the rate of osteogenesis. Osteocyte lacunae and canaliculi, the cavities in bone containing osteocytes and their extensions, were measured in thin-sections of primary (woven and parallel fibered bone in a diversity of tetrapods. The results indicate that bone cell surfaces are more densely organized in the Saurischia (extant birds, extinct Mesozoic Theropoda and Sauropodomorpha than in other tetrapods, a result of denser branching of the cell extensions. The highest postnatal growth rates among extant tetrapods occur in modern birds, the only surviving saurischians, and the finding of exceptional cytoplasmic surface area of the cells that produce bone in this group suggests a relationship with bone growth rate. In support of this relationship is finding the lowest cell surface density among the saurischians examined in Dinornis, a member of a group of ratites that evolved in New Zealand in isolation from mammalian predators and show other evidence of lowered maturation rates.

  9. Bone cells in birds show exceptional surface area, a characteristic tracing back to saurischian dinosaurs of the late Triassic.

    Science.gov (United States)

    Rensberger, John M; Martínez, Ricardo N

    2015-01-01

    Dinosaurs are unique among terrestrial tetrapods in their body sizes, which range from less than 3 gm in hummingbirds to 70,000 kg or more in sauropods. Studies of the microstructure of bone tissue have indicated that large dinosaurs, once believed to be slow growing, attained maturity at rates comparable to or greater than those of large mammals. A number of structural criteria in bone tissue have been used to assess differences in rates of osteogenesis in extinct taxa, including counts of lines of arrested growth and the density of vascular canals. Here, we examine the density of the cytoplasmic surface of bone-producing cells, a feature which may set an upper limit to the rate of osteogenesis. Osteocyte lacunae and canaliculi, the cavities in bone containing osteocytes and their extensions, were measured in thin-sections of primary (woven and parallel fibered) bone in a diversity of tetrapods. The results indicate that bone cell surfaces are more densely organized in the Saurischia (extant birds, extinct Mesozoic Theropoda and Sauropodomorpha) than in other tetrapods, a result of denser branching of the cell extensions. The highest postnatal growth rates among extant tetrapods occur in modern birds, the only surviving saurischians, and the finding of exceptional cytoplasmic surface area of the cells that produce bone in this group suggests a relationship with bone growth rate. In support of this relationship is finding the lowest cell surface density among the saurischians examined in Dinornis, a member of a group of ratites that evolved in New Zealand in isolation from mammalian predators and show other evidence of lowered maturation rates.

  10. Observation of Stable Low Surface Resistance in Large-Grain Niobium SRF Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Geng, Rongli [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Huang, Shichun [Institute of Modern Physics (IMP)/Chinese Academy of Sciences (CAS), Lanzhou (China)

    2016-05-01

    Low surface resistance, or high unloaded quality factor (Q0), superconducting radio frequency (SRF) cavities are being pursued actively nowadays as their application in large-scale CW SRF accelerators can save capital and operational cost in cryogenics. There are different options in realization of such cavities. One of them is the large-grain (LG) niobium cavity. In this contribution, we present new experimental results in evaluation of LG niobium cavities cooled down in the presence of an external magnetic field. High Q0 values are achieved even with an ambient magnetic field of up to 100 mG. More over, it is observed that these high Q0 values are super-robust against repeated quench, literally not affected at all after the cavity being deliberately quenched for hundreds of times in the presence of an ambient magnetic field of up to 200 mG.

  11. Surface transport and stable trapping of particles and cells by an optical waveguide loop.

    Science.gov (United States)

    Hellesø, Olav Gaute; Løvhaugen, Pål; Subramanian, Ananth Z; Wilkinson, James S; Ahluwalia, Balpreet Singh

    2012-09-21

    Waveguide trapping has emerged as a useful technique for parallel and planar transport of particles and biological cells and can be integrated with lab-on-a-chip applications. However, particles trapped on waveguides are continuously propelled forward along the surface of the waveguide. This limits the practical usability of the waveguide trapping technique with other functions (e.g. analysis, imaging) that require particles to be stationary during diagnosis. In this paper, an optical waveguide loop with an intentional gap at the centre is proposed to hold propelled particles and cells. The waveguide acts as a conveyor belt to transport and deliver the particles/cells towards the gap. At the gap, the diverging light fields hold the particles at a fixed position. The proposed waveguide design is numerically studied and experimentally implemented. The optical forces on the particle at the gap are calculated using the finite element method. Experimentally, the method is used to transport and trap micro-particles and red blood cells at the gap with varying separations. The waveguides are only 180 nm thick and thus could be integrated with other functions on the chip, e.g. microfluidics or optical detection, to make an on-chip system for single cell analysis and to study the interaction between cells.

  12. CONDITIONS FOR STABLE CHIP BREAKING AND PROVISION OF MACHINED SURFACE QUALITY WHILE TURNING WITH ASYMMETRIC TOOL VIBRATIONS

    Directory of Open Access Journals (Sweden)

    V. K. Sheleh

    2015-01-01

    Full Text Available The paper considers a process of turning structural steel with asymmetric tool vibrations directed along feeding. Asymmetric vibrations characterized by asymmetry coefficient of vibration cycle, their frequency and amplitude are additionally transferred to the tool in the turning process with the purpose to crush chips. Conditions of stable chip breaking and obtaining optimum dimensions of chip elements have been determined in the paper. In order to reduce a negative impact of the vibration amplitude on a cutting process and quality of the machined surfaces machining must be carried out with its minimum value. In this case certain ratio of the tool vibration frequency to the work-piece rotation speed has been ensured in the paper. A formula has been obtained for calculation of this ratio with due account of the expected length of chip elements and coefficient of vibration cycle asymmetry.Influence of the asymmetric coefficient of the tool vibration cycle on roughness of the machined surfaces and cutting tool wear has been determined in the paper. According to the results pertaining to machining of work-pieces made of 45 and ШХ15 steel the paper presents mathematical relationships of machined surface roughness with cutting modes and asymmetry coefficient of tool vibration cycle. Tool feeding being one of the cutting modes exerts the most significant impact on the roughness value and increase of the tool feeding entails increase in roughness. Reduction in coefficient of vibration cycle asymmetry contributes to surface roughness reduction. However, the cutting tool wear occurs more intensive. Coefficient of the vibration cycle asymmetry must be increased in order to reduce wear rate. Therefore, the choice of the coefficient of the vibration cycle asymmetry is based on the parameters of surface roughness which must be obtained after machining and intensity of tool wear rate.The paper considers a process of turning structural steel with asymmetric

  13. The role of energetic ions from plasma in the creation of nanostructured materials and stable polymer surface treatments

    International Nuclear Information System (INIS)

    Bilek, M.M.M.; Newton-McGee, K.; McKenzie, D.R.; McCulloch, D.G.

    2006-01-01

    Plasma processes for the synthesis of new materials as thin films have enabled the production of a wide variety of new materials. These include meta-stable phases, which are not readily found in nature, and more recently, materials with structure on the nanoscale. Study of plasma synthesis processes at the fundamental level has revealed that ion energy, depositing flux and growth surface temperature are the critical parameters affecting the microstructure and the properties of the thin film materials formed. In this paper, we focus on the role of ion flux and impact energy in the creation of thin films with nanoscale structure in the form of multilayers. We describe three synthesis strategies, based on the extraction of ions from plasma sources and involving modulation of ion flux and ion energy. The microstructure, intrinsic stress and physical properties of the multilayered samples synthesized are studied and related back to the conditions at the growth surface during deposition. When energetic ions of a non-condensing species are used, it is possible to place active groups on the surfaces of materials such as polymers. These active groups can then be used as bonding sites in subsequent chemical attachment of proteins or other macromolecules. If the energy of the non-condensing ions is increased to a few keV then modified layers buried under the surface can be produced. Here we describe a method by which the aging effect, which is often observed in plasma surface modifications on polymers, can be reduced and even eliminated using high energy ion bombardment

  14. Fabricating a Homogeneously Alloyed AuAg Shell on Au Nanorods to Achieve Strong, Stable, and Tunable Surface Plasmon Resonances

    KAUST Repository

    Huang, Jianfeng

    2015-08-13

    Colloidal metal nanocrystals with strong, stable, and tunable localized surface plasmon resonances (SPRs) can be useful in a corrosive environment for many applications including field-enhanced spectroscopies, plasmon-mediated catalysis, etc. Here, a new synthetic strategy is reported that enables the epitaxial growth of a homogeneously alloyed AuAg shell on Au nanorod seeds, circumventing the phase segregation of Au and Ag encountered in conventional synthesis. The resulting core–shell structured bimetallic nanorods (AuNR@AuAg) have well-mixed Au and Ag atoms in their shell without discernible domains. This degree of mixing allows AuNR@AuAg to combine the high stability of Au with the superior plasmonic activity of Ag, thus outperforming seemingly similar nanostructures with monometallic shells (e.g., Ag-coated Au NRs (AuNR@Ag) and Au-coated Au NRs (AuNR@Au)). AuNR@AuAg is comparable to AuNR@Ag in plasmonic activity, but that it is markedly more stable toward oxidative treatment. Specifically, AuNR@AuAg and AuNR@Ag exhibit similarly strong signals in surface-enhanced Raman spectroscopy that are some 30-fold higher than that of AuNR@Au. When incubated with a H2O2 solution (0.5 m), the plasmonic activity of AuNR@Ag immediately and severely decayed, whereas AuNR@AuAg retained its activity intact. Moreover, the longitudinal SPR frequency of AuNR@AuAg can be tuned throughout the red wavelengths (≈620–690 nm) by controlling the thickness of the AuAg alloy shell. The synthetic strategy is versatile to fabricate AuAg alloyed shells on different shaped Au, with prospects for new possibilities in the synthesis and application of plasmonic nanocrystals.

  15. Effects of core strength training using stable versus unstable surfaces on physical fitness in adolescents: a randomized controlled trial.

    Science.gov (United States)

    Granacher, Urs; Schellbach, Jörg; Klein, Katja; Prieske, Olaf; Baeyens, Jean-Pierre; Muehlbauer, Thomas

    2014-01-01

    It has been demonstrated that core strength training is an effective means to enhance trunk muscle strength (TMS) and proxies of physical fitness in youth. Of note, cross-sectional studies revealed that the inclusion of unstable elements in core strengthening exercises produced increases in trunk muscle activity and thus provide potential extra training stimuli for performance enhancement. Thus, utilizing unstable surfaces during core strength training may even produce larger performance gains. However, the effects of core strength training using unstable surfaces are unresolved in youth. This randomized controlled study specifically investigated the effects of core strength training performed on stable surfaces (CSTS) compared to unstable surfaces (CSTU) on physical fitness in school-aged children. Twenty-seven (14 girls, 13 boys) healthy subjects (mean age: 14 ± 1 years, age range: 13-15 years) were randomly assigned to a CSTS (n = 13) or a CSTU (n = 14) group. Both training programs lasted 6 weeks (2 sessions/week) and included frontal, dorsal, and lateral core exercises. During CSTU, these exercises were conducted on unstable surfaces (e.g., TOGU© DYNAIR CUSSIONS, THERA-BAND© STABILITY TRAINER). Significant main effects of Time (pre vs. post) were observed for the TMS tests (8-22%, f = 0.47-0.76), the jumping sideways test (4-5%, f = 1.07), and the Y balance test (2-3%, f = 0.46-0.49). Trends towards significance were found for the standing long jump test (1-3%, f = 0.39) and the stand-and-reach test (0-2%, f = 0.39). We could not detect any significant main effects of Group. Significant Time x Group interactions were detected for the stand-and-reach test in favour of the CSTU group (2%, f = 0.54). Core strength training resulted in significant increases in proxies of physical fitness in adolescents. However, CSTU as compared to CSTS had only limited additional effects (i.e., stand-and-reach test). Consequently, if the

  16. Study, using stable isotopes, of flow distribution, surface-groundwater relations and evapotranspiration in the Okavango Swamp, Botswana

    International Nuclear Information System (INIS)

    Dincer, T.; Hutton, L.G.; Kupee, B.B.J.

    1979-01-01

    Stable isotope data collected in the Okavango Delta have confirmed that the central distributary system is more active at present than the peripheral systems. The data also show that there is no groundwater outflow at the western and southern margins of the delta. A salinity-isotope model of the deltaic swamp has been developed to study the relation between the salinity and isotopic composition of the swamp waters. An attempt has been made to separate the atmospheric losses from the swamp into its evapotranspiration components. The results indicate that in winter, when high water levels prevail, these losses are almost entirely due to evaporation whilst in summer, when the water levels are low, evaporation and transpiration contribute almost equally to the total atmospheric losses. (author)

  17. Properties of the surface snow in Princess Elizabeth Land, East Antarctica - climate and non-climate dependent variability of the surface mass balance and stable water isotopic composition

    Science.gov (United States)

    Vladimirova, D.; Ekaykin, A.; Lipenkov, V.; Popov, S. V.; Petit, J. R.; Masson-Delmotte, V.

    2017-12-01

    Glaciological and meteorological observations conducted during the past four decades in Princess Elizabeth Land, East Antarctica, are compiled. The database is used to investigate spatial patterns of surface snow isotopic composition and surface mass balance, including detailed information near subglacial lake Vostok. We show diverse relationships between snow isotopic composition and surface temperature. In the most inland part (elevation 3200-3400 m a.s.l.), surface snow isotopic composition varies independently from surface temperature, and is closely related to the distance to the open water source (with a slope of 0.98±0.17 ‰ per 100 km). Surface mass balance values are higher along the ice sheet slope, and relatively evenly distributed inland. The minimum values of snow isotopic composition and surface mass balance are identified in an area XX km southwestward from Vostok station. The spatial distribution of deuterium excess delineates regions influenced by the Indian Ocean and Pacific Ocean air masses, with Vostok area being situated close to their boundary. Anomalously high deuterium excess values are observed near Dome A, suggesting high kinetic fractionation for its moisture source, or specifically high post-deposition artifacts. The dataset is available for further studies such as the assessment of skills of general circulation or regional atmospheric models, and the search for the oldest ice.

  18. Analysis of pushing exercises: muscle activity and spine load while contrasting techniques on stable surfaces with a labile suspension strap training system.

    Science.gov (United States)

    McGill, Stuart M; Cannon, Jordan; Andersen, Jordan T

    2014-01-01

    Labile surfaces in the form of suspension straps are increasingly being used as a tool in resistance training programs. Pushing is a common functional activity of daily living and inherently part of a well-rounded training program. This study examined pushing exercises performed on stable surfaces and unstable suspension straps, specifically muscle activation levels and spine loads were quantified together with the influence of employing technique coaching. There were several main questions that this study sought to answer: Which exercises challenged particular muscles? What was the magnitude of the resulting spine load? How did stable and unstable surfaces differ? Did coaching influence the results? Fourteen men were recruited as part of a convenience sample (mean age, 21.1 ± 2.0 years; height, 1.77 ± 0.06 m; mean weight, 74.6 ± 7.8 kg). Data were processed and input to a sophisticated and anatomically detailed 3D model that used muscle activity and body segment kinematics to estimate muscle force-in this way, the model was sensitive to the individuals choice of motor control for each task; muscle forces and linked segment joint loads were used to calculate spine loads. Exercises were performed using stable surfaces for hand/feet contact and repeated where possible with labile suspension straps. Speed of movement was standardized across participants with the use of a metronome for each exercise. There were gradations of muscle activity and spine load characteristics to every task. In general, the instability associated with the labile exercises required greater torso muscle activity than when performed on stable surfaces. Throughout the duration of an exercise, there was a range of compression; the TRX push-up ranged from 1,653 to 2,128.14 N, whereas the standard push-up had a range from 1,233.75 to 1,530.06 N. There was no significant effect of exercise on spine compression (F(4,60) = 0.86, p = 0.495). Interestingly, a standard push-up showed significantly

  19. Raman microspectroscopy, surface-enhanced Raman scattering microspectroscopy, and stable-isotope Raman microspectroscopy for biofilm characterization.

    Science.gov (United States)

    Ivleva, Natalia P; Kubryk, Patrick; Niessner, Reinhard

    2017-07-01

    Biofilms represent the predominant form of microbial life on our planet. These aggregates of microorganisms, which are embedded in a matrix formed by extracellular polymeric substances, may colonize nearly all interfaces. Detailed knowledge of microorganisms enclosed in biofilms as well as of the chemical composition, structure, and functions of the complex biofilm matrix and their changes at different stages of the biofilm formation and under various physical and chemical conditions is relevant in different fields. Important research topics include the development and improvement of antibiotics and medical devices and the optimization of biocides, antifouling strategies, and biological wastewater treatment. Raman microspectroscopy is a capable and nondestructive tool that can provide detailed two-dimensional and three-dimensional chemical information about biofilm constituents with the spatial resolution of an optical microscope and without interference from water. However, the sensitivity of Raman microspectroscopy is rather limited, which hampers the applicability of Raman microspectroscopy especially at low biomass concentrations. Fortunately, the resonance Raman effect as well as surface-enhanced Raman scattering can help to overcome this drawback. Furthermore, the combination of Raman microspectroscopy with other microscopic techniques, mass spectrometry techniques, or particularly with stable-isotope techniques can provide comprehensive information on monospecies and multispecies biofilms. Here, an overview of different Raman microspectroscopic techniques, including resonance Raman microspectroscopy and surface-enhanced Raman scattering microspectroscopy, for in situ detection, visualization, identification, and chemical characterization of biofilms is given, and the main feasibilities and limitations of these techniques in biofilm research are presented. Future possibilities of and challenges for Raman microspectroscopy alone and in combination with other

  20. Metal nanoinks as chemically stable surface enhanced scattering (SERS) probes for the analysis of blue BIC ballpoint pens.

    Science.gov (United States)

    Alyami, A; Saviello, D; McAuliffe, M A P; Mirabile, A; Lewis, L; Iacopino, D

    2017-06-07

    Metal nanoinks constituted by Ag nanoparticles and Au nanorods were employed as probes for the Surface Enhanced Raman Scattering (SERS) analysis of a blue BIC ballpoint pen. The dye components of the pen ink were first separated by thin layer chromatography (TLC) and subsequently analysed by SERS at illumination wavelengths of 514 nm and 785 nm. Compared to normal Raman conditions, enhanced spectra were obtained for all separated spots, allowing easy identification of phthalocyanine Blue 38 and triarylene crystal violet in the ink mixture. A combination of effects such as molecular resonance, electromagnetic and chemical effects were the contributing factors to the generation of spectra enhanced compared to normal Raman conditions. Enhancement factors (EFs) between 5 × 10 3 and 3 × 10 6 were obtained, depending on the combination of SERS probes and laser illumination used. In contrast to previous conflicting reports, the metal nanoinks were chemically stable, allowing the collection of reproducible spectra for days after deposition on TLC plates. In addition and in advance to previously reported SERS probes, no need for additional aggregating agents or correction of electrostatic charge was necessary to induce the generation of enhanced SERS spectra.

  1. Chemically stable Au nanorods as probes for sensitive surface enhanced scattering (SERS) analysis of blue BIC ballpoint pens

    Science.gov (United States)

    Alyami, Abeer; Saviello, Daniela; McAuliffe, Micheal A. P.; Cucciniello, Raffaele; Mirabile, Antonio; Proto, Antonio; Lewis, Liam; Iacopino, Daniela

    2017-08-01

    Au nanorods were used as an alternative to commonly used Ag nanoparticles as Surface Enhanced Raman Scattering (SERS) probes for identification of dye composition of blue BIC ballpoint pens. When used in combination with Thin Layer Chromatography (TLC), Au nanorod colloids allowed identification of the major dye components of the BIC pen ink, otherwise not identifiable by normal Raman spectroscopy. Thanks to their enhanced chemical stability compared to Ag colloids, Au nanorods provided stable and reproducible SERS signals and allowed easy identification of phthalocyanine and triarylene dyes in the pen ink mixture. These findings were supported by FTIR and MALDI analyses, also performed on the pen ink. Furthermore, the self-assembly of Au nanorods into large area ordered superstructures allowed identification of BIC pen traces. SERS spectra of good intensity and high reproducibility were obtained using Au nanorod vertical arrays, due to the high density of hot spots and morphological reproducibility of these superstructures. These results open the way to the employment of SERS for fast screening analysis and for quantitative analysis of pens and faded pens which are relevant for the fields of forensic and art conservation sciences.

  2. Intense and stable surface-enhanced Raman scattering from Ag@mesoporous SiO{sub 2} film

    Energy Technology Data Exchange (ETDEWEB)

    Long, Yongjin; Wang, Xiaolong; Chen, Dong; Jiang, Tao, E-mail: jiangtao@nbu.edu.cn; Zhao, Ziqi; Zhou, Jun, E-mail: zhoujun@nbu.edu.cn

    2016-09-15

    A surface-enhanced Raman scattering (SERS) film consisting of mesoporous silica (MSiO{sub 2}) coated Ag nanoparticles (NPs) was achieved. The as-prepared hybrid NPs were uniform in size and formed large amount of aggregates in the film. “Hot spots” were supposed to appear in the MSiO{sub 2} shells with an average size as small as 15 nm. Such a novel core–shell structure therefore induced the enhancement of SERS intensity compared to the film of bare Ag NPs and polymer film of Ag-CMC. The homogeneity and stability of SERS signals from the Ag@MSiO{sub 2} film were also tested. A relative standard deviation of SERS intensity lower than 20% from Raman mapping and a stable SERS signal with excitation power of 100 mW were observed, which were both better than the other two films. Moreover, the obtained Ag@MSiO{sub 2} film was applied to detect thiram pesticides and a detection limit as low as 1×10{sup −8} M was reached, which indicates the advantages of the Ag@MSiO{sub 2} film in biosensor.

  3. Single-mode temperature and polarisation-stable high-speed 850nm vertical cavity surface emitting lasers

    International Nuclear Information System (INIS)

    Nazaruk, D E; Blokhin, S A; Maleev, N A; Bobrov, M A; Pavlov, M M; Kulagina, M M; Vashanova, K A; Zadiranov, Yu M; Ustinov, V M; Kuzmenkov, A G; Vasil'ev, A P; Gladyshev, A G; Blokhin, A A; Salut, 7 Larina Str, N Novgorod, 603950 (Russian Federation))" data-affiliation=" (JSV Salut, 7 Larina Str, N Novgorod, 603950 (Russian Federation))" >Fefelov, A G

    2014-01-01

    A new intracavity-contacted design to realize temperature and polarization-stable high-speed single-mode 850 nm vertical cavity surface emitting lasers (VCSELs) grown by molecular-beam epitaxy is proposed. Temperature dependences of static and dynamic characteristics of the 4.5 pm oxide aperture InGaAlAs VCSEL were investigated in detail. Due to optimal gain-cavity detuning and enhanced carrier localization in the active region the threshold current remains below 0.75 mA for the temperature range within 20-90°C, while the output power exceeds 1 mW up to 90°C. Single-mode operation with side-mode suppression ratio higher than 30 dB and orthogonal polarization suppression ratio more than 18 dB was obtained in the whole current and temperature operation range. Device demonstrates serial resistance less than 250 Ohm, which is rather low for any type of single-mode short- wavelength VCSELs. VCSEL demonstrates temperature robust high-speed operation with modulation bandwidth higher than 13 GHz in the entire temperature range of 20-90°C. Despite high resonance frequency the high-speed performance of developed VCSELs was limited by the cut-off frequency of the parasitic low pass filter created by device resistances and capacitances. The proposed design is promising for single-mode high-speed VCSEL applications in a wide spectral range

  4. Quantification of Gaseous Elemental Mercury Dry Deposition to Environmental Surfaces using Mercury Stable Isotopes in a Controlled Environment

    Science.gov (United States)

    Rutter, A. P.; Schauer, J. J.; Shafer, M. M.; Olson, M.; Robinson, M.; Vanderveer, P.; Creswell, J. E.; Parman, A.; Mallek, J.; Gorski, P.

    2009-12-01

    atmospheric turbulence and wind speed. GEM enriched in stable isotope 198 (GEM-198) was released into the room from source at elevated but environmentally relevant concentrations of GEM-198 for several days. Uptake of GEM-198 from deciduous and conifer trees, grass turf, 3 types of soil, sand, concrete, asphalt, and adsorbent coated deposition coupons were quantified over several days. Exposures were conducted between 10oC and 30oC, in dark and light conditions. Mercury was recovered from the samples using acidic digestions and surface leaches, and then analyzed for the content of GEM-198 by high resolution ICPMS. Experimental results demonstrated that uptake by White Ash, White Spruce, and Kentucky bluegrass were significantly higher than uptakes measured for two Wisconsin soils, peat, sand, concrete and asphalt at all of the conditions studied. Deposition resistances for surface transfer processes for were calculated for each of the substrates across the conditions studied for use in atmospheric model simulations.

  5. Sn surface-enriched Pt-Sn bimetallic nanoparticles as a selective and stable catalyst for propane dehydrogenation

    KAUST Repository

    Zhu, Haibo

    2014-12-01

    A new one pot, surfactant-free, synthetic route based on the surface organometallic chemistry (SOMC) concept has been developed for the synthesis of Sn surface-enriched Pt-Sn nanoparticles. Bu3SnH selectively reacts with [Pt]-H formed in situ at the surface of Pt nanoparticles, Pt NPs, obtained by reduction of K2PtCl4 by LiB(C2H5)3H. Chemical analysis, 1H MAS and 13C CP/MAS solid-state NMR as well as two-dimensional double-quantum (DQ) and triple-quantum (TQ) experiments show that organo-tin moieties Sn(n-C4H9) are chemically linked to the surface of Pt NPs to produce, in fine, after removal of most of the n-butyl fragment, bimetallic Pt-Sn nanoparticles. The Sn(n-CH2CH2CH2CH3) groups remaining at the surface are believed to stabilize the as-synthesized Pt-Sn NPs, enabling the bimetallic NPs to be well dispersed in THF. Additionally, the Pt-Sn nanoparticles can be supported on MgAl2O4 during the synthesis of the nanoparticles. Some of the Pt-Sn/MgAl2O4 catalyst thus prepared exhibits high activity in PROX of CO and an extremely high selectivity and stability in propane dehydrogenation to propylene. The enhanced activity in propane dehydrogenation is associated with the high concentration of inactive Sn at the surface of Pt nanoparticles which ”isolates” the active Pt atoms. This conclusion is confirmed by XRD, NMR, TEM, and XPS analysis.

  6. Quantification of long-term wastewater fluxes at the surface water/groundwater-interface: an integrative model perspective using stable isotopes and acesulfame.

    Science.gov (United States)

    Engelhardt, I; Barth, J A C; Bol, R; Schulz, M; Ternes, T A; Schüth, C; van Geldern, R

    2014-01-01

    The suitability of acesulfame to trace wastewater-related surface water fluxes from streams into the hyporheic and riparian zones over long-term periods was investigated. The transport behavior of acesulfame was compared with the transport of water stable isotopes (δ(18)O or δ(2)H). A calibrated model based on a joint inversion of temperature, acesulfame, and piezometric pressure heads was employed in a model validation using data sets of acesulfame and water stable isotopes collected over 5months in a stream and groundwater. The spatial distribution of fresh water within the groundwater resulting from surface water infiltration was estimated by computing groundwater ages and compared with the predicted acesulfame plume obtained after 153day simulation time. Both, surface water ratios calculated with a mixing equation from water stable isotopes and simulated acesulfame mass fluxes, were investigated for their ability to estimate the contribution of wastewater-related surface water inflow within groundwater. The results of this study point to limitations for the application of acesulfame to trace surface water-groundwater interactions properly. Acesulfame completely missed the wastewater-related surface water volumes that still remained in the hyporheic zone under stream-gaining conditions. In contrast, under stream-losing conditions, which developed after periods of stagnating hydraulic exchange, acesulfame based predictions lead to an overestimation of the surface water volume of up to 25% in the riparian zone. If slow seepage velocities prevail a proportion of acesulfame might be stored in smaller pores, while when released under fast flowing water conditions it will travel further downstream with the groundwater flow direction. Therefore, under such conditions acesulfame can be a less-ideal tracer in the hyporheic and riparian zones and additional monitoring with other environmental tracers such as water stable isotopes is highly recommended. © 2013 Elsevier

  7. Hydrogeochemistry and quality of surface water and groundwater in the vicinity of Lake Monoun, West Cameroon: approach from multivariate statistical analysis and stable isotopic characterization.

    Science.gov (United States)

    Kamtchueng, Brice T; Fantong, Wilson Y; Wirmvem, Mengnjo J; Tiodjio, Rosine E; Takounjou, Alain F; Ndam Ngoupayou, Jules R; Kusakabe, Minoru; Zhang, Jing; Ohba, Takeshi; Tanyileke, Gregory; Hell, Joseph V; Ueda, Akira

    2016-09-01

    With the use of conventional hydrogeochemical techniques, multivariate statistical analysis, and stable isotope approaches, this paper investigates for the first time surface water and groundwater from the surrounding areas of Lake Monoun (LM), West Cameroon. The results reveal that waters are generally slightly acidic to neutral. The relative abundance of major dissolved species are Ca(2+) > Mg(2+) > Na(+) > K(+) for cations and HCO3 (-) ≫ NO3 (-) > Cl(-) > SO4 (2-) for anions. The main water type is Ca-Mg-HCO3. Observed salinity is related to water-rock interaction, ion exchange process, and anthropogenic activities. Nitrate and chloride have been identified as the most common pollutants. These pollutants are attributed to the chlorination of wells and leaching from pit latrines and refuse dumps. The stable isotopic compositions in the investigated water sources suggest evidence of evaporation before recharge. Four major groups of waters were identified by salinity and NO3 concentrations using the Q-mode hierarchical cluster analysis (HCA). Consistent with the isotopic results, group 1 represents fresh unpolluted water occurring near the recharge zone in the general flow regime; groups 2 and 3 are mixed water whose composition is controlled by both weathering of rock-forming minerals and anthropogenic activities; group 4 represents water under high vulnerability of anthropogenic pollution. Moreover, the isotopic results and the HCA showed that the CO2-rich bottom water of LM belongs to an isolated hydrological system within the Foumbot plain. Except for some springs, groundwater water in the area is inappropriate for drinking and domestic purposes but good to excellent for irrigation.

  8. Stable Boundary Layer Issues

    OpenAIRE

    Steeneveld, G.J.

    2012-01-01

    Understanding and prediction of the stable atmospheric boundary layer is a challenging task. Many physical processes are relevant in the stable boundary layer, i.e. turbulence, radiation, land surface coupling, orographic turbulent and gravity wave drag, and land surface heterogeneity. The development of robust stable boundary layer parameterizations for use in NWP and climate models is hampered by the multiplicity of processes and their unknown interactions. As a result, these models suffer ...

  9. Stable Boundary Layer Issues

    NARCIS (Netherlands)

    Steeneveld, G.J.

    2012-01-01

    Understanding and prediction of the stable atmospheric boundary layer is a challenging task. Many physical processes are relevant in the stable boundary layer, i.e. turbulence, radiation, land surface coupling, orographic turbulent and gravity wave drag, and land surface heterogeneity. The

  10. PECVD-ONO: A New Deposited Firing Stable Rear Surface Passivation Layer System for Crystalline Silicon Solar Cells

    Directory of Open Access Journals (Sweden)

    M. Hofmann

    2008-01-01

    Full Text Available A novel plasma-enhanced chemical vapour deposited (PECVD stack layer system consisting of a-SiOx:H, a-SiNx:H, and a-SiOx:H is presented for silicon solar cell rear side passivation. Surface recombination velocities below 60 cm/s (after firing and below 30 cm/s (after forming gas anneal were achieved. Solar cell precursors without front and rear metallisation showed implied open-circuit voltages Voc values extracted from quasi-steady-state photoconductance (QSSPC measurements above 680 mV. Fully finished solar cells with up to 20.0% energy conversion efficiency are presented. A fit of the cell's internal quantum efficiency using software tool PC1D and a comparison to a full-area aluminium-back surface field (Al-BSF and thermal SiO2 is shown. PECVD-ONO was found to be clearly superior to Al-BSF. A separation of recombination at the metallised and the passivated area at the solar cell's rear is presented using the equations of Fischer and Kray. Nuclear reaction analysis (NRA has been used to evaluate the hydrogen depth profile of the passivation layer system at different stages.

  11. Technology of stable, prolonged-release eye-drops containing Cyclosporine A, distributed between lipid matrix and surface of the solid lipid microspheres (SLM).

    Science.gov (United States)

    Wolska, Eliza; Sznitowska, Małgorzata

    2013-01-30

    The aim of this study was to prepare solid lipid microspheres (SLM) with incorporated Cyclosporine A (Cs), suitable for ocular application. For this purpose, SLM were formulated by using different lipids and three different nonionic surfactants. The SLM were produced using a hot emulsification method. The SLM dispersions contained 10, 20 or 30% of lipid (w/w) and up to 2% (w/w) of Cs. The size of the microspheres with Cs ranged from 1 to 15 μm. Physically stable SLM with Cs were prepared using Compritol, as a lipid matrix, and Tween 80, as a surfactant. In contrast, dispersion with Precirol alone, formed semi-solid gels during storage, while in formulations with Precirol and Miglyol, crystals of Cs were observed. In vitro release profile of Compritol formulations showed that 40% of Cs is released within 1h, while the release of the following 40% takes more time, depending on lipid content in the formulations. The large part of Cs, added to SLM formulations (from 45 to 80%), was found on the surface of microparticles, but no drug crystallization occurred during a long-term storage. Copyright © 2012 Elsevier B.V. All rights reserved.

  12. Quantification of long-term wastewater fluxes at the surface water/groundwater-interface: An integrative model perspective using stable isotopes and acesulfame

    Energy Technology Data Exchange (ETDEWEB)

    Engelhardt, I., E-mail: i.engelhardt@fz-juelich.de [Forschungszentrum Jülich, Institute of Bio- and Geosciences, Agrosphere — IBG-3 (Germany); Technical University of Darmstadt, Institute of Applied Geosciences (Germany); Barth, J.A.C. [GeoZentrum Nordbayern, University of Erlangen-Nuremberg (Germany); Bol, R. [Forschungszentrum Jülich, Institute of Bio- and Geosciences, Agrosphere — IBG-3 (Germany); Schulz, M.; Ternes, T.A. [Federal Institute of Hydrology (BfG) (Germany); Schüth, C. [Technical University of Darmstadt, Institute of Applied Geosciences (Germany); van Geldern, R. [GeoZentrum Nordbayern, University of Erlangen-Nuremberg (Germany)

    2014-01-01

    The suitability of acesulfame to trace wastewater-related surface water fluxes from streams into the hyporheic and riparian zones over long-term periods was investigated. The transport behavior of acesulfame was compared with the transport of water stable isotopes (δ{sup 18}O or δ{sup 2}H). A calibrated model based on a joint inversion of temperature, acesulfame, and piezometric pressure heads was employed in a model validation using data sets of acesulfame and water stable isotopes collected over 5 months in a stream and groundwater. The spatial distribution of fresh water within the groundwater resulting from surface water infiltration was estimated by computing groundwater ages and compared with the predicted acesulfame plume obtained after 153 day simulation time. Both, surface water ratios calculated with a mixing equation from water stable isotopes and simulated acesulfame mass fluxes, were investigated for their ability to estimate the contribution of wastewater-related surface water inflow within groundwater. The results of this study point to limitations for the application of acesulfame to trace surface water–groundwater interactions properly. Acesulfame completely missed the wastewater-related surface water volumes that still remained in the hyporheic zone under stream-gaining conditions. In contrast, under stream-losing conditions, which developed after periods of stagnating hydraulic exchange, acesulfame based predictions lead to an overestimation of the surface water volume of up to 25% in the riparian zone. If slow seepage velocities prevail a proportion of acesulfame might be stored in smaller pores, while when released under fast flowing water conditions it will travel further downstream with the groundwater flow direction. Therefore, under such conditions acesulfame can be a less-ideal tracer in the hyporheic and riparian zones and additional monitoring with other environmental tracers such as water stable isotopes is highly recommended

  13. Xyloglucan endotransglucosylase/hydrolases (XTHs) are inactivated by binding to glass and cellulosic surfaces, and released in active form by a heat-stable polymer from cauliflower florets.

    Science.gov (United States)

    Sharples, Sandra C; Nguyen-Phan, Tu C; Fry, Stephen C

    2017-11-01

    Xyloglucan endotransglucosylase (XET) activity, which cuts and re-joins hemicellulose chains in the plant cell wall, contributing to wall assembly and growth regulation, is the major activity of XTH proteins. During purification, XTHs often lose XET activity which, however, is restored by treatment with certain cold-water-extractable, heat-stable polymers (CHPs), e.g. from cauliflower florets. It was not known whether the XTH-activating factor (XAF) present in CHPs works by promoting (e.g. allosterically) XET activity or by re-solubilising sequestered XTH proteins. We now show that XTHs in dilute solution bind to diverse surfaces (e.g. glass and cellulose), and that CHPs can re-solubilise the bound enzyme, re-activating it. Cell walls prepared from cauliflower florets, mung bean shoots and Arabidopsis cell-suspension cultures each contained endogenous, tightly bound, inactive XTHs, which were likewise rapidly solubilised (within 0.5h) and thus activated by cauliflower XAF. We present a convenient quantitative assay for XAF acting on the native sequestered XTHs of Arabidopsis cell walls; using this assay, we show that CHPs from all plants tested possess XAF activity. The XAF activity of diverse CHPs does not correlate with their conductivity, showing that this activity is not a simple ionic effect. The XAF action of cauliflower CHPs was augmented by NaCl, although NaCl alone was much less effective than a CHP solution of similar conductivity, confirming that the cauliflower polymers did not simply exert a salt effect. We suggest that XAF is an endogenous regulator of XET action, modulating cell-wall loosening and/or assembly in vivo. Copyright © 2017 The Authors. Published by Elsevier GmbH.. All rights reserved.

  14. Near-Surface Profiles of Water Stable Isotope Components and Indicated Transitional History of Ice-Wedge Polygons Near Barrow

    Science.gov (United States)

    Iwahana, G.; Wilson, C.; Newman, B. D.; Heikoop, J. M.; Busey, R.

    2017-12-01

    Wetlands associated with ice-wedge polygons are commonly distributed across the Arctic Coastal Plain of northern Alaska, a region underlain by continuous permafrost. Micro-topography of the ice-wedge polygons controls local hydrology, and the micro-topography could be altered due to factors such like surface vegetation, wetness, freeze-thaw cycles, and permafrost degradation/aggradation under climate change. Understanding status of the wetlands in the near future is important because it determines biogeochemical cycle, which drives release of greenhouse gases from the ground. However, transitional regime of the ice-wedge polygons under the changing climate is not fully understood. In this study, we analyzed geochemistry of water extracted from frozen soil cores sampled down to about 1m depth in 2014 March at NGEE-Arctic sites in the Barrow Environmental Observatory. The cores were sampled from troughs/rims/centers of five different low-centered or flat-centered polygons. The frozen cores are divided into 5-10cm cores for each location, thawed in sealed plastic bags, and then extracted water was stored in vials. Comparison between the profiles of geochemistry indicated connection of soil water in the active layer at different location in a polygon, while it revealed that distinctly different water has been stored in permafrost layer at troughs/rims/centers of some polygons. Profiles of volumetric water content (VWC) showed clear signals of freeze-up desiccation in the middle of saturated active layers as low VWC anomalies at most sampling points. Water in the active layer and near-surface permafrost was classified into four categories: ice wedge / fresh meteoric / transitional / highly fractionated water. The overall results suggested prolonged separation of water in the active layer at the center of low-centered polygons without lateral connection in water path in the past.

  15. Tracing the origin of Pb using stable Pb isotopes in surface sediments along the Korean Yellow Sea coast

    Science.gov (United States)

    Park, Jong-Kyu; Choi, Man-Sik; Song, Yunho; Lim, Dhong-Il

    2017-06-01

    To investigate the factors controlling lead (Pb) concentration and identify the sources of Pb in Yellow Sea sediments along the Korean coast, the concentration of Pb and Pb isotopes in 87 surface and 6 core sediment samples were analyzed. The 1 M HCl leached Pb concentrations had a similar geographic distribution to those of fine-grained sediments, while the distribution of residual Pb concentrations resembled that of coarse-grained sediments. Leached Pb was presumed to be associated with manganese (Mn) oxide and iron (Fe) oxy/hydroxide, while residual Pb was associated with potassium (K)-feldspar, based on good linear relationships between the leached Pb and the Fe/Mn concentrations, and the residual Pb and K concentrations. Based on a ratio-ratio plot with three isotopes (207Pb/206Pb and 208Pb/206Pb) and the geographic location of each sediment, sediments were categorized into two groups of samples as group1 and group2. Group 1 sediments, which were distributed in Gyeonggi Bay and offshore (north of 36.5°N), were determined to be a mixture of anthropogenic and natural Pb originating from the Han River, based on a 208Pb/206Pb against a Cs/Pbleached mixing plot of core and surface sediments. Group 2 sediments, which were distributed in the south of 36.5°N, also showed a two endmembers mixing relationship between materials from the Geum River and offshore materials, which had very different Pb concentrations and isotope ratios. Based on the isotopes and their concentrations in core and surface sediments, this mixing relationship was interpreted as materials from two geographically different origins being mixed, rather than anthropogenic or natural mixing of materials with the same origin. Therefore, the relative percentage of materials supplied from the Geum River was calculated using a two endmembers mixing model and estimated to be as much as about 50% at 35°N. The spatial distribution of materials derived from the Geum River represented that of fine

  16. Stable isotopes

    International Nuclear Information System (INIS)

    Brazier, J.L.; Guinamant, J.L.

    1995-01-01

    According to the progress which has been realised in the technology of separating and measuring isotopes, the stable isotopes are used as preferable 'labelling elements' for big number of applications. The isotopic composition of natural products shows significant variations as a result of different reasons like the climate, the seasons, or their geographic origins. So, it was proved that the same product has a different isotopic composition of alimentary and agriculture products. It is also important in detecting the pharmacological and medical chemicals. This review article deals with the technology, like chromatography and spectrophotometry, adapted to this aim, and some important applications. 17 refs. 6 figs

  17. Conditions for Stable Chip Breaking and Provision of Machined Surface Quality While Turning with Asymmetric Tool Vibrations

    OpenAIRE

    Шелег, В. К.; Молочко, В. И.; Данильчик, С. С.

    2015-01-01

    The paper considers a process of turning structural steel with asymmetric tool vibrations directed along feeding. Asymmetric vibrations characterized by asymmetry coefficient of vibration cycle, their frequency and amplitude are additionally transferred to the tool in the turning process with the purpose to crush chips. Conditions of stable chip breaking and obtaining optimum dimensions of chip elements have been determined in the paper. In order to reduce a negative impact of the vibration a...

  18. Distribution of mean surface stable isotopes values in east Antarctica; observed changes with depth in coastal area

    International Nuclear Information System (INIS)

    Lorius, C.; Merlivat, L.

    1975-01-01

    Mean samples of the snow accumulated during the last ten years have been collected at 48 stations distributed along a 850km long axis in East Antarctica, starting from Dumont d'Urville towards Vostok. Up to 1000m elevations the mean deuterium values are rather constant (-150 per thousand); then they decrease with various parameters (distance, elevation) and in particular with the mean annual temperatures, according to a linear relationship (D per thousand=6,04T(degC)-51) for a temperature range from -20 to -55 deg C. The observed D per thousand-O per thousand relationship is discussed. Measurements along a 303m deep core (down to the bedrock) obtained in the control area show very large D changes with mean values varying between -150 and -360 per thousand; this last value characterizes present surface snow deposited about 800km upstream. The observed D variations may be explained by changes in the site of origin of the ice; mechanisms which could explain the presence of ice originating from further distances above less distant origin layers are discussed [fr

  19. Sn surface-enriched Pt-Sn bimetallic nanoparticles as a selective and stable catalyst for propane dehydrogenation

    KAUST Repository

    Zhu, Haibo; Anjum, Dalaver H.; Wang, Qingxiao; Abou-Hamad, Edy; Emsley, Lyndon; Dong, Hailin; Laveille, Paco; Li, Lidong; Samal, Akshaya Kumar; Basset, Jean-Marie

    2014-01-01

    Sn(n-C4H9) are chemically linked to the surface of Pt NPs to produce, in fine, after removal of most of the n-butyl fragment, bimetallic Pt-Sn nanoparticles. The Sn(n-CH2CH2CH2CH3) groups remaining at the surface are believed to stabilize the as

  20. Characterising flow regime and interrelation between surface-water and ground-water in the Fuente de Piedra salt lake basin by means of stable isotopes, hydrogeochemical and hydraulic data

    Science.gov (United States)

    Kohfahl, Claus; Rodriguez, Miguel; Fenk, Cord; Menz, Christian; Benavente, Jose; Hubberten, Hans; Meyer, Hanno; Paul, Liisa; Knappe, Andrea; López-Geta, Juan Antonio; Pekdeger, Asaf

    2008-03-01

    SummaryThis research reports the characterisation of ground- and surface-water interaction in the Fuente de Piedra Salt lake basin in southern Spain by a combined approach using hydraulic, hydrogeochemical and stable isotope data. During three sampling campaigns (February 2004, 2005 and October 2005) ground- and surface-water samples were collected for stable isotope studies ( 18O, D) and for major and minor ion analysis. Hydraulic measurements at multilevel piezometers were carried out at four different locations around the lake edge. Conductivity logs were performed at four piezometers located along a profile at the northern lake border and at two deeper piezometers in the Miocene basin at a greater distance from the lake. To describe processes that control the brine evolution different hydrogeochemical simulations were performed. Hydrogeochemical data show a variety of brines related to thickness variations of lacustrine evaporites around the lake. Salinity profiles in combination with stable isotope and hydraulic data indicate the existence of convection cells and recycled brines. Furthermore restricted ground-water inflow into the lake was detected. Dedolomitisation processes were identified by hydrogeochemical simulations and different brine origins were reproduced by inverse modelling approaches.

  1. On a free-surface problem with moving contact line: From variational principles to stable numerical approximations

    Science.gov (United States)

    Fumagalli, Ivan; Parolini, Nicola; Verani, Marco

    2018-02-01

    We analyze a free-surface problem described by time-dependent Navier-Stokes equations. Surface tension, capillary effects and wall friction are taken into account in the evolution of the system, influencing the motion of the contact line - where the free surface hits the wall - and of the dynamics of the contact angle. The differential equations governing the phenomenon are first derived from the variational principle of minimum reduced dissipation, and then discretized by means of the ALE approach. The numerical properties of the resulting scheme are investigated, drawing a parallel with the physical properties holding at the continuous level. Some instability issues are addressed in detail, in the case of an explicit treatment of the geometry, and novel additional terms are introduced in the discrete formulation in order to damp the instabilities. Numerical tests assess the suitability of the approach, the influence of the parameters, and the effectiveness of the new stabilizing terms.

  2. Evolution of subpolar North Atlantic surface circulation since the early Holocene inferred from planktic foraminifera faunal and stable isotope records

    DEFF Research Database (Denmark)

    Staines-Urias, Francisca; Kuijpers, Antoon; Korte, Christoph

    2013-01-01

    of the Faroe Islands, are located in the transitional area where surface waters of subpolar and subtropical origin mix before entering the Arctic Mediterranean. In these areas, large-amplitude millennial variability in the characteristics of the upper-water column appears modulated by changes in the intensity...

  3. Formation of ZnO-Cd(OH){sub 2} core-shell nanoparticles by sol-gel method: An approach to modify surface chemistry for stable and enhanced green emission

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, Rupali, E-mail: rupalimishra@rediffmail.co [Department of Physics, University of Allahabad, Allahabad-211002 (India); Nanophosphor Application Centre, University of Allahabad, Allahabad-211002 (India); Yadav, Raghvendra S.; Pandey, Avinash C. [Department of Physics, University of Allahabad, Allahabad-211002 (India); Nanophosphor Application Centre, University of Allahabad, Allahabad-211002 (India); Sanjay, Sharda. S. [Department of Chemistry, Ewing Christian College, Allahabad (India); Dar, Chitra [Department of Physics, University of Allahabad, Allahabad-211002 (India)

    2010-03-15

    We report the formation of highly stable and luminescent ZnO-Cd(OH){sub 2} core-shell nanoparticles by simple introduction of cadmium salt in the initial precursor solution, used to synthesize ZnO nanoparticles by sol-gel route. The cadmium to zinc salt concentration ratio has been also varied to control the growth of ZnO nanoparticles at the smaller particle size. Formation of ZnO-Cd(OH){sub 2} core-shell nanostructure has been confirmed by X-ray diffraction (XRD), energy dispersive analysis of X-rays (EDAX) and X-ray photoelectron spectroscopy (XPS). UV-vis absorption spectroscopy exhibits blue-shift in absorption edge on increasing cadmium concentrations. The photoluminescence emission spectra showed the remarkably stable and enhanced visible (green) emission from suspended ZnO-Cd(OH){sub 2} nanoparticles in comparison to bare ZnO nanoparticles. It is postulated that Cd(OH){sub 2} layer at the surface of ZnO nanoparticles prevents the agglomeration of nanoparticles and efficiently assists the trapping of hole at the surface site, a first step necessary for visible emission. The Fourier transform infrared spectroscopy (FTIR) also supports our assumption about surface chemistry.

  4. Intracellular surface-enhanced Raman scattering (SERS) with thermally stable gold nanoflowers grown from Pt and Pd seeds

    KAUST Repository

    Song, Hyon Min

    2013-01-01

    SERS provides great sensitivity at low concentrations of analytes. SERS combined with near infrared (NIR)-resonant gold nanomaterials are important candidates for theranostic agents due to their combined extinction properties and sensing abilities stemming from the deep penetration of laser light in the NIR region. Here, highly branched gold nanoflowers (GNFs) grown from Pd and Pt seeds are prepared and their SERS properties are studied. The growth was performed at 80°C without stirring, and this high temperature growth method is assumed to provide great shape stability of sharp tips in GNFs. We found that seed size must be large enough (>30 nm in diameter) to induce the growth of those SERS-active and thermally stable GNFs. We also found that the addition of silver nitrate (AgNO3) is important to induce sharp tip growth and shape stability. Incubation with Hela cells indicates that GNFs are taken up and reside in the cytoplasm. SERS was observed in those cells incubated with 1,10-phenanthroline (Phen)-loaded GNFs. This journal is © 2013 The Royal Society of Chemistry.

  5. Intracellular surface-enhanced Raman scattering (SERS) with thermally stable gold nanoflowers grown from Pt and Pd seeds.

    Science.gov (United States)

    Song, Hyon Min; Deng, Lin; Khashab, Niveen M

    2013-05-21

    SERS provides great sensitivity at low concentrations of analytes. SERS combined with near infrared (NIR)-resonant gold nanomaterials are important candidates for theranostic agents due to their combined extinction properties and sensing abilities stemming from the deep penetration of laser light in the NIR region. Here, highly branched gold nanoflowers (GNFs) grown from Pd and Pt seeds are prepared and their SERS properties are studied. The growth was performed at 80 °C without stirring, and this high temperature growth method is assumed to provide great shape stability of sharp tips in GNFs. We found that seed size must be large enough (>30 nm in diameter) to induce the growth of those SERS-active and thermally stable GNFs. We also found that the addition of silver nitrate (AgNO3) is important to induce sharp tip growth and shape stability. Incubation with Hela cells indicates that GNFs are taken up and reside in the cytoplasm. SERS was observed in those cells incubated with 1,10-phenanthroline (Phen)-loaded GNFs.

  6. Stable isotopes

    International Nuclear Information System (INIS)

    Evans, D.K.

    1986-01-01

    Seventy-five percent of the world's stable isotope supply comes from one producer, Oak Ridge Nuclear Laboratory (ORNL) in the US. Canadian concern is that foreign needs will be met only after domestic needs, thus creating a shortage of stable isotopes in Canada. This article describes the present situation in Canada (availability and cost) of stable isotopes, the isotope enrichment techniques, and related research programs at Chalk River Nuclear Laboratories (CRNL)

  7. Searching for stable Si(n)C(n) clusters: combination of stochastic potential surface search and pseudopotential plane-wave Car-Parinello simulated annealing simulations.

    Science.gov (United States)

    Duan, Xiaofeng F; Burggraf, Larry W; Huang, Lingyu

    2013-07-22

    To find low energy Si(n)C(n) structures out of hundreds to thousands of isomers we have developed a general method to search for stable isomeric structures that combines Stochastic Potential Surface Search and Pseudopotential Plane-Wave Density Functional Theory Car-Parinello Molecular Dynamics simulated annealing (PSPW-CPMD-SA). We enhanced the Sunders stochastic search method to generate random cluster structures used as seed structures for PSPW-CPMD-SA simulations. This method ensures that each SA simulation samples a different potential surface region to find the regional minimum structure. By iterations of this automated, parallel process on a high performance computer we located hundreds to more than a thousand stable isomers for each Si(n)C(n) cluster. Among these, five to 10 of the lowest energy isomers were further optimized using B3LYP/cc-pVTZ method. We applied this method to Si(n)C(n) (n = 4-12) clusters and found the lowest energy structures, most not previously reported. By analyzing the bonding patterns of low energy structures of each Si(n)C(n) cluster, we observed that carbon segregations tend to form condensed conjugated rings while Si connects to unsaturated bonds at the periphery of the carbon segregation as single atoms or clusters when n is small and when n is large a silicon network spans over the carbon segregation region.

  8. Searching for Stable SinCn Clusters: Combination of Stochastic Potential Surface Search and Pseudopotential Plane-Wave Car-Parinello Simulated Annealing Simulations

    Directory of Open Access Journals (Sweden)

    Larry W. Burggraf

    2013-07-01

    Full Text Available To find low energy SinCn structures out of hundreds to thousands of isomers we have developed a general method to search for stable isomeric structures that combines Stochastic Potential Surface Search and Pseudopotential Plane-Wave Density Functional Theory Car-Parinello Molecular Dynamics simulated annealing (PSPW-CPMD-SA. We enhanced the Sunders stochastic search method to generate random cluster structures used as seed structures for PSPW-CPMD-SA simulations. This method ensures that each SA simulation samples a different potential surface region to find the regional minimum structure. By iterations of this automated, parallel process on a high performance computer we located hundreds to more than a thousand stable isomers for each SinCn cluster. Among these, five to 10 of the lowest energy isomers were further optimized using B3LYP/cc-pVTZ method. We applied this method to SinCn (n = 4–12 clusters and found the lowest energy structures, most not previously reported. By analyzing the bonding patterns of low energy structures of each SinCn cluster, we observed that carbon segregations tend to form condensed conjugated rings while Si connects to unsaturated bonds at the periphery of the carbon segregation as single atoms or clusters when n is small and when n is large a silicon network spans over the carbon segregation region.

  9. Atomic structure of a stable high-index Ge surface: G2(103)-(4x1)

    DEFF Research Database (Denmark)

    Seehofer, L.; Bunk, O.; Falkenberg, G.

    1997-01-01

    Based on scanning tunneling microscopy and surface X-ray diffraction, we propose a complex structural model for the Ge(103)-(4 x 1) reconstruction. Each unit cell contains two (103) double steps, which gives rise to the formation of stripes of Ge atoms oriented in the [] direction....... The stripes and the spaces between them are covered with threefold-coordinated Ge adatoms. Charge is transferred from the bulk-like edge atoms of the double steps to the adatoms. The formation of the reconstruction can be explained in terms of stress relief, charge transfer, and minimization of the dangling...

  10. A ternary functional Ag@GO@Au sandwiched hybrid as an ultrasensitive and stable surface enhanced Raman scattering platform

    Science.gov (United States)

    Zhang, Cong-yun; Hao, Rui; Zhao, Bin; Hao, Yao-wu; Liu, Ya-qing

    2017-07-01

    The graphene-mediated surface enhanced Raman scattering (SERS) substrates by virtues of plasmonic metal nanostructures and graphene or its derivatives have attracted tremendous interests which are expected to make up the deficiency of traditional plasmonic metal substrates. Herein, we designed and fabricated a novel ternary Ag@GO@Au sandwich hybrid wherein the ultrathin graphene oxide (GO) films were seamlessly wrapped around the hierarchical flower-like Ag particle core and meanwhile provided two-dimensional anchoring scaffold for the coating of Au nanoparticles (NPs). The surface coverage density of loading Au NPs could be readily controlled by tuning the dosage amount of Au particle solutions. These features endowed the sandwiched structures high enrichment capability for analytes such as aromatic molecules and astonishing SERS performance. The Raman signals were enormously enhanced with an ultrasensitive detection limit of rhodamine-6G (R6G) as low as 10-13 M based on the chemical enhancement from GO and multi-dimensional plasmonic coupling between the metal nanoparticles. In addition, the GO interlayer as an isolating shell could effectively prevent the metal-molecule direct interaction and suppress the oxidation of Ag after exposure at ambient condition which enabled the substrates excellent reproducibility with less than 6% signal variations and prolonged life-time. To evaluate the feasibility and the practical application for SERS detection in real-world samples based on GO sandwiched hybrid as SERS-active substrate, three different prohibited colorants with a series of concentrations were measured with a minimum detected concentration down to 10-9 M. Furthermore, the prepared GO sandwiched nanostructures can be used to identify different types of colorants existing in red wine, implying the great potential applications for single-particle SERS sensing of biotechnology and on-site monitoring in food security.

  11. Hyperspectral surface materials map of quadrangle 3564, Jowand (405) and Gurziwan (406) quadrangles, Afghanistan, showing carbonates, phyllosilicates, sulfates, altered minerals, and other materials

    Science.gov (United States)

    Kokaly, Raymond F.; King, Trude V.V.; Hoefen, Todd M.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected carbonates, phyllosilicates, sulfates, altered minerals, and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. The map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Epidote or chlorite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  12. Hyperspectral surface materials map of quadrangle 3264, Naw Zad-Musa Qala (423) and Dihrawud (424) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  13. Hyperspectral surface materials map of quadrangle 3266, Uruzgan (519) and Moqur (520) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Giles, Stuart A.; Johnson, Michaela R.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  14. Hyperspectral surface materials map of quadrangle 3464, Shahrak (411) and Kasi (412) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  15. Hyperspectral surface materials map of quadrangle 3466, La`l wa Sar Jangal (507) and Bamyan (508) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Giles, Stuart A.; Johnson, Michaela R.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  16. Hyperspectral surface materials map of quadrangle 3260, Dasht-e-Chah-e-Mazar (419) and Anar Darah (420) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  17. Hyperspectral surface materials map of quadrangle 3470, Jalalabad (511) and Chaghasaray (512) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Giles, Stuart A.; Johnson, Michaela R.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  18. Hyperspectral surface materials map of quadrangle 3570, Tagab-e-Munjan (505) and Asmar-Kamdesh (506) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  19. Hyperspectral surface materials map of quadrangle 3364, Pasaband (417) and Markaz-e Kajiran (418) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  20. Hyperspectral surface materials map of quadrangle 3462, Herat (409) and Chishti Sharif (410) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  1. Hyperspectral surface materials map of quadrangle 3468, Chak-e Wardak-Siyahgird (509) and Kabul (510) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Giles, Stuart A.; Johnson, Michaela R.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  2. Hyperspectral surface materials map of quadrangle 3368, Ghazni (515) and Gardez (516) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  3. Hyperspectral surface materials map of quadrangle 3162, Chakhansur (603) and Kotalak (604) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  4. Hyperspectral surface materials map of quadrangle 3362, Shindand (415) and Tulak (416) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Giles, Stuart A.; Johnson, Michaela R.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  5. Hyperspectral surface materials map of quadrangle 3366, Gizab (513) and Nawer (514) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  6. Hyperspectral surface materials map of quadrangle 3770, Faizabad (217) and Parkhaw (218) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Giles, Stuart A.; Johnson, Michaela R.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  7. Hyperspectral surface materials map of quadrangle 3564, Jowand (405) and Gurziwan (406) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  8. Hyperspectral surface materials map of quadrangle 3166, Jaldak (701) and Maruf-Nawa (702) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Giles, Stuart A.; Johnson, Michaela R.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  9. Hyperspectral surface materials map of quadrangle 3566, Sangcharak (501) and Sayghan-o-Kamard (502) quadrangles, Afghanistan, showing iron-bearing minerals and other material

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Giles, Stuart A.; Johnson, Michaela R.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  10. Hyperspectral surface materials map of quadrangle 3670, Jurm-Kishim (223) and Zebak (224) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  11. Hyperspectral surface materials map of quadrangle 3568, Pul-e Khumri (503) and Charikar (504) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  12. Hyperspectral surface materials map of quadrangle 3262, Farah (421) and Hokumat-e-pur-Chaman (422) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  13. Hyperspectral surface materials map of quadrangle 3164, Lashkar Gah (605) and Kandahar (606) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  14. Hyperspectral surface materials map of quadrangle 3562, Khawja-Jir (403) and Murghab (404) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  15. Hyperspectral Surface Materials Map of Quadrangle 3268, Khayr Kot (521) and Urgun (522) Quadrangles, Afghanistan, Showing Iron-bearing Minerals and Other Materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Giles, Stuart A.; Johnson, Michaela R.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  16. Stable isotopes of hydrogen and oxygen in surface water and ground water at selected sites on or near the Idaho National Engineering Laboratory, Idaho

    International Nuclear Information System (INIS)

    Ott, D.S.; Cecil, L.D.; Knobel, L.L.

    1994-01-01

    Relative stable isotopic ratios for hydrogen and oxygen compared to standard mean ocean water are presented for water from 4 surface-water sites and 38 ground-water sites on or near the Idaho National Engineering Laboratory (INEL). The surface-water samples were collected monthly from March 1991 through April 1992 and after a storm event on June 18, 1992. The ground-water samples either were collected during 1991 or 1992. These data were collected as part of the US Geological Survey's continuing hydrogeological investigations at the INEL. The relative isotopic ratios of hydrogen and oxygen are reported as delta 2 H (δ 2 H) and as delta 18 O (δ 18 O), respectively. The values of δ 2 H and δ 18 O in water from the four surface-water sites ranged from -143.0 to -122 and from -18.75 to -15.55, respectively. The values of δ 2 H and δ 18 O in water from the 38 ground-water sites ranged from -141.0 to -120.0 and from -18.55 to -14.95, respectively

  17. Temperature stable LiNbO3 surface acoustic wave device with diode sputtered amorphous TeO2 over-layer

    International Nuclear Information System (INIS)

    Dewan, Namrata; Tomar, Monika; Gupta, Vinay; Sreenivas, K.

    2005-01-01

    Amorphous TeO 2 thin film, sputtered in the O 2 +Ar(25%+75%) gas environment using a metallic tellurium target, has been identified as an attractive negative temperature coefficient of delay (TCD) material that can yield a temperature stable device when combined with a surface acoustic wave (SAW) device based on positive TCD material such as LiNbO 3 . The influence of amorphous TeO 2 over-layer on the SAW propagation characteristics (velocity and temperature coefficient of delay) of the SAW filters (36 and 70 MHz) based on 128 deg. rotated Y-cut X-propagating lithium niobate (128 deg. Y-X LiNbO 3 ) single crystal has been studied. It is found that 0.042 λ thick TeO 2 over-layer on a prefabricated SAW device operating at 36 MHz centre frequency, reduces the TCD of the device from 76 ppm deg. C -1 to almost zero (∼1.4 ppm deg. C -1 ) without deteriorating its efficiency and could be considered as a suitable alternative for temperature stable devices in comparison to conventional SiO 2 over-layer

  18. Oxygen and silicon stable isotopes of diatom silica. Reconstructing changes in surface water hydrography and silicic acid utilization in the late Pleistocene subarctic Pacific

    Energy Technology Data Exchange (ETDEWEB)

    Maier, Edith

    2014-03-05

    Deglacial variations in upper ocean nutrient dynamics and stratification in high latitudes, as well as associated changes in thermohaline overturning circulation, are thought to have played a key role in changing atmospheric CO{sub 2} concentrations. This thesis examines the relationship between past changes in subarctic Pacific upper ocean stratification and nutrient (silicic acid) utilization, using oxygen and silicon stable isotopes of diatom silica, for the first time at millennial-scale resolution and analyzed with a new and efficient instrumentation set-up. The isotopic data, presented in three manuscripts, show a consistent picture of millennial-scale variability in upper ocean stratification and silicic acid utilization during the last ∝50 ka BP, e.g. indicating that the subarctic Pacific was a source region for atmospheric CO{sub 2} during the last deglaciation (late Heinrich Stadial 1 and the Boelling/Alleroed). The presented results demonstrate the high potential of combined diatom oxygen and silicon stable isotope analysis especially for, but not restricted to, marine regions characterized by a low biogenic carbonate content like the subarctic Pacific and the Southern Ocean.

  19. Oxygen and silicon stable isotopes of diatom silica. Reconstructing changes in surface water hydrography and silicic acid utilization in the late Pleistocene subarctic Pacific

    International Nuclear Information System (INIS)

    Maier, Edith

    2014-01-01

    Deglacial variations in upper ocean nutrient dynamics and stratification in high latitudes, as well as associated changes in thermohaline overturning circulation, are thought to have played a key role in changing atmospheric CO 2 concentrations. This thesis examines the relationship between past changes in subarctic Pacific upper ocean stratification and nutrient (silicic acid) utilization, using oxygen and silicon stable isotopes of diatom silica, for the first time at millennial-scale resolution and analyzed with a new and efficient instrumentation set-up. The isotopic data, presented in three manuscripts, show a consistent picture of millennial-scale variability in upper ocean stratification and silicic acid utilization during the last ∝50 ka BP, e.g. indicating that the subarctic Pacific was a source region for atmospheric CO 2 during the last deglaciation (late Heinrich Stadial 1 and the Boelling/Alleroed). The presented results demonstrate the high potential of combined diatom oxygen and silicon stable isotope analysis especially for, but not restricted to, marine regions characterized by a low biogenic carbonate content like the subarctic Pacific and the Southern Ocean.

  20. Unpredictably Stable

    DEFF Research Database (Denmark)

    Failla, Virgilio; Melillo, Francesca; Reichstein, Toke

    2014-01-01

    Is entrepreneurship a more stable career choice for high employment turnover individuals? We find that a transition to entrepreneurship induces a shift towards stayer behavior and identify job matching, job satisfaction and lock-in effects as main drivers. These findings have major implications...

  1. Stable particles

    International Nuclear Information System (INIS)

    Samios, N.P.

    1993-01-01

    I have been asked to review the subject of stable particles, essentially the particles that eventually comprised the meson and baryon octets. with a few more additions -- with an emphasis on the contributions made by experiments utilizing the bubble chamber technique. In this activity, much work had been done by the photographic emulsion technique and cloud chambers-exposed to cosmic rays as well as accelerator based beams. In fact, many if not most of the stable particles were found by these latter two techniques, however, the forte of the bubble chamber (coupled with the newer and more powerful accelerators) was to verify, and reinforce with large statistics, the existence of these states, to find some of the more difficult ones, mainly neutrals and further to elucidate their properties, i.e., spin, parity, lifetimes, decay parameters, etc

  2. Stable isotope oxygen-18 and deuterium analysis in surface and groundwater of the Jequitibá Creek Basin, Sete Lagoas, MG

    Energy Technology Data Exchange (ETDEWEB)

    Linhares, Giovanna Maria Gardini; Moreira, Rubens Martins; Pimenta, Rafael Colombo; Scarpelli, Raquel Pazzini; Santos, Elizangela Augusta dos, E-mail: giovannagardini@gmail.com, E-mail: rubens@cdtn.br, E-mail: colombopimenta@gmail.com, E-mail: raquelscarpelli@gmail.com, E-mail: elizangela.augusta@gmail.com [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2017-07-01

    Groundwater is an important source of public and industrial supplies, and inadequate exploitation of water reflects negatively on its quality and production of wells, especially when located in karstic aquifers. The study area includes the Maize and Sorghum National Research / Embrapa, located in the karst region of Sete Lagoas, within of the Jequitibá creek sub-basin, an affluent of the Velhas River. The evaluation of the content of stable isotopes of hydrogen ({sup 2}H), or deuterium, and oxygen ({sup 18}O) of surface waters (lagoons) and groundwater (production and monitoring wells) collected from the study area allowed to know directly the origin of these waters, active climatic processes and interactions between different aquifers and surface bodies, as possible mixtures of water from different sources. The collected samples were analyzed by isotopic ratio mass spectrometry, IRMS Advantege - Thermo Science, from the Center for the Development of Nuclear Technology (CDTN). The mean values found for δ{sup 18}O and δ{sup 2}H in the waters of the monitoring wells were -6.40‰ and -43.21‰, respectively. For the production wells, mean values for δ{sup 18}O and δ{sup 2}H of -5.87 ‰ and -40.09‰, respectively, were obtained. When compared to GMWL, the collected groundwater originates attributed to the precipitations. The lagoon waters had mean values for δ{sup 18}O and δ{sup 2}H of -3.73‰ and -30.08‰. The water collected in the crystalline fissured aquifer presented mean values δ{sup 18}O and δ{sup 2}H of -6.91‰ and -40.26 ‰ respectively, in its rockier portion, and -6.09‰ and -43.05‰. (author)

  3. Stable isotope oxygen-18 and deuterium analysis in surface and groundwater of the Jequitibá Creek Basin, Sete Lagoas, MG

    International Nuclear Information System (INIS)

    Linhares, Giovanna Maria Gardini; Moreira, Rubens Martins; Pimenta, Rafael Colombo; Scarpelli, Raquel Pazzini; Santos, Elizangela Augusta dos

    2017-01-01

    Groundwater is an important source of public and industrial supplies, and inadequate exploitation of water reflects negatively on its quality and production of wells, especially when located in karstic aquifers. The study area includes the Maize and Sorghum National Research / Embrapa, located in the karst region of Sete Lagoas, within of the Jequitibá creek sub-basin, an affluent of the Velhas River. The evaluation of the content of stable isotopes of hydrogen ( 2 H), or deuterium, and oxygen ( 18 O) of surface waters (lagoons) and groundwater (production and monitoring wells) collected from the study area allowed to know directly the origin of these waters, active climatic processes and interactions between different aquifers and surface bodies, as possible mixtures of water from different sources. The collected samples were analyzed by isotopic ratio mass spectrometry, IRMS Advantege - Thermo Science, from the Center for the Development of Nuclear Technology (CDTN). The mean values found for δ 18 O and δ 2 H in the waters of the monitoring wells were -6.40‰ and -43.21‰, respectively. For the production wells, mean values for δ 18 O and δ 2 H of -5.87 ‰ and -40.09‰, respectively, were obtained. When compared to GMWL, the collected groundwater originates attributed to the precipitations. The lagoon waters had mean values for δ 18 O and δ 2 H of -3.73‰ and -30.08‰. The water collected in the crystalline fissured aquifer presented mean values δ 18 O and δ 2 H of -6.91‰ and -40.26 ‰ respectively, in its rockier portion, and -6.09‰ and -43.05‰. (author)

  4. Surface plasmon resonance analysis shows an IgG-isotype-specific defect in ABO blood group antibody formation in patients with common variable immunodeficiency

    Directory of Open Access Journals (Sweden)

    Michael Bernhard Fischer

    2015-05-01

    Full Text Available Background: Common variable immunodeficiency (CVID is the most common clinically severe primary immunodeficiency and comprises a heterogeneous group of patients with recurrent severe bacterial infections due to the failure to produce IgG antibodies after exposure to infectious agents and immunization. Diagnostic recommendations for antibody failure include assessment of isoagglutinins. We have readdressed this four decades old but still accepted recommendation with up to date methodology.Methods: Anti-A/B IgM- and IgG-antibodies were measured by Diamed-ID Micro Typing, surface plasmon resonance (SPR using the Biacore® device and flow cytometry.Results: When Diamed-ID Micro Typing was used, CVID patients (n=34 showed IgG- and IgM-isoagglutinins that were comparable to healthy volunteers (n=28, while all XLA patients (n=8 had none. Anti-A/B IgM-antibodies were present in more than 2/3 of the CVID patients and showed binding kinetics comparable to anti-A/B IgM-antibodies from healthy individuals. A correlation could be found in CVID patients between levels of anti-A/B IgM-antibodies and levels of serum IgM and PnP-IgM-antibodies. In contrast in CVID patients as a group ABO antibodies were significantly decreased when assessed by SPR, which correlated with levels of switched memory, non-switched memory and naïve B cells, but all CVID patients had low/undetectable anti-A/B IgG-antibodies.Conclusion: These results indicate that conventional isoagglutinin assessment and assessment of anti-A/B IgM antibodies are not suited for the diagnosis of impaired antibody production in CVID. Examination of anti-A/B IgG antibodies by SPR provides a useful method for the diagnosis of IgG antibody failure in all CVID patients studied, thus indicating an important additional rationale to start immunoglobulin replacement therapy early in these patients, before post-infectious sequelae develop.

  5. Stable Tetraquarks

    Energy Technology Data Exchange (ETDEWEB)

    Quigg, Chris [Fermilab

    2018-04-13

    For very heavy quarks, relations derived from heavy-quark symmetry imply novel narrow doubly heavy tetraquark states containing two heavy quarks and two light antiquarks. We predict that double-beauty states will be stable against strong decays, whereas the double-charm states and mixed beauty+charm states will dissociate into pairs of heavy-light mesons. Observing a new double-beauty state through its weak decays would establish the existence of tetraquarks and illuminate the role of heavy color-antitriplet diquarks as hadron constituents.

  6. Stable beams

    CERN Multimedia

    2015-01-01

    Stable beams: two simple words that carry so much meaning at CERN. When LHC page one switched from "squeeze" to "stable beams" at 10.40 a.m. on Wednesday, 3 June, it triggered scenes of jubilation in control rooms around the CERN sites, as the LHC experiments started to record physics data for the first time in 27 months. This is what CERN is here for, and it’s great to be back in business after such a long period of preparation for the next stage in the LHC adventure.   I’ve said it before, but I’ll say it again. This was a great achievement, and testimony to the hard and dedicated work of so many people in the global CERN community. I could start to list the teams that have contributed, but that would be a mistake. Instead, I’d simply like to say that an achievement as impressive as running the LHC – a machine of superlatives in every respect – takes the combined effort and enthusiasm of everyone ...

  7. Calcium stable isotope geochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Gausonne, Nikolaus [Muenster Univ. (Germany). Inst. fuer Mineralogie; Schmitt, Anne-Desiree [Strasbourg Univ. (France). LHyGeS/EOST; Heuser, Alexander [Bonn Univ. (Germany). Steinmann-Inst. fuer Geologie, Mineralogie und Palaeontologie; Wombacher, Frank [Koeln Univ. (Germany). Inst. fuer Geologie und Mineralogie; Dietzel, Martin [Technische Univ. Graz (Austria). Inst. fuer Angewandte Geowissenschaften; Tipper, Edward [Cambridge Univ. (United Kingdom). Dept. of Earth Sciences; Schiller, Martin [Copenhagen Univ. (Denmark). Natural History Museum of Denmark

    2016-08-01

    This book provides an overview of the fundamentals and reference values for Ca stable isotope research, as well as current analytical methodologies including detailed instructions for sample preparation and isotope analysis. As such, it introduces readers to the different fields of application, including low-temperature mineral precipitation and biomineralisation, Earth surface processes and global cycling, high-temperature processes and cosmochemistry, and lastly human studies and biomedical applications. The current state of the art in these major areas is discussed, and open questions and possible future directions are identified. In terms of its depth and coverage, the current work extends and complements the previous reviews of Ca stable isotope geochemistry, addressing the needs of graduate students and advanced researchers who want to familiarize themselves with Ca stable isotope research.

  8. Calcium stable isotope geochemistry

    International Nuclear Information System (INIS)

    Gausonne, Nikolaus; Schmitt, Anne-Desiree; Heuser, Alexander; Wombacher, Frank; Dietzel, Martin; Tipper, Edward; Schiller, Martin

    2016-01-01

    This book provides an overview of the fundamentals and reference values for Ca stable isotope research, as well as current analytical methodologies including detailed instructions for sample preparation and isotope analysis. As such, it introduces readers to the different fields of application, including low-temperature mineral precipitation and biomineralisation, Earth surface processes and global cycling, high-temperature processes and cosmochemistry, and lastly human studies and biomedical applications. The current state of the art in these major areas is discussed, and open questions and possible future directions are identified. In terms of its depth and coverage, the current work extends and complements the previous reviews of Ca stable isotope geochemistry, addressing the needs of graduate students and advanced researchers who want to familiarize themselves with Ca stable isotope research.

  9. The use of a well-defined surface organometallic complex as a probe molecule: [(≡SiO)TaVCl2Me2] shows different isolated silanol sites on the silica surface

    KAUST Repository

    Chen, Yin

    2014-01-01

    TaVCl2Me3 reacts with silica(700) and produces two different [(≡SiO)TaVCl2Me2] surface organometallic species, suggesting a heterogeneity of the highly dehydroxylated silica surface, which was studied with a combined experimental and theoretical approach. This journal is © the Partner Organisations 2014.

  10. The use of a well-defined surface organometallic complex as a probe molecule: [(≡SiO)TaVCl2Me2] shows different isolated silanol sites on the silica surface

    KAUST Repository

    Chen, Yin; Zheng, Bin; Abou-Hamad, Edy; Hamieh, Ali Imad Ali; Hamzaoui, Bilel; Huang, Kuo-Wei; Basset, Jean-Marie

    2014-01-01

    TaVCl2Me3 reacts with silica(700) and produces two different [(≡SiO)TaVCl2Me2] surface organometallic species, suggesting a heterogeneity of the highly dehydroxylated silica surface, which was studied with a combined experimental and theoretical approach. This journal is © the Partner Organisations 2014.

  11. Stable3

    Indian Academy of Sciences (India)

    ... S, T, U, V, W, X, Y. 1, Supplementary table 3. All 2,853 putative orthorlogous gene pairs between rice and Arabidopsis and their responses towards N starvation stress. These genes showed differential expression in at least one treatment and one spieces. Cell colored in magenta represents up-regulated in corresponding ...

  12. Small-scale orographic gravity wave drag in stable boundary layers and its impact on synoptic systems and near surface meteorology

    NARCIS (Netherlands)

    Tsiringakis, Aristofanis; Steeneveld, G.J.; Holtslag, A.A.M.

    2017-01-01

    At present atmospheric models for weather and climate use enhanced turbulent drag under stable conditions, because these empirically provide the necessary momentum drag for accurate forecast of synoptic systems. The enhanced mixing (also known as the "long-tail"), introduces drag that can not be

  13. Fabrication of long-term stable superoleophobic surface based on copper oxide/cobalt oxide with micro-nanoscale hierarchical roughness

    Science.gov (United States)

    Barthwal, Sumit; Lim, Si-Hyung

    2015-02-01

    We have demonstrated a simple and cost-effective technique for the large-area fabrication of a superoleophobic surface using copper as a substrate. The whole process included three simple steps: First, the copper substrate was oxidized under hot alkaline conditions to fabricate flower-like copper oxide microspheres by heating at a particular temperature for an interval of time. Second, the copper-oxide-covered copper substrate was further heated in a solution of cobalt nitrate and ammonium nitrate in the presence of an ammonia solution to fabricate cobalt oxide nanostructures. We applied this second step to increase the surface roughness because it is an important criterion for improved superoleophobicity. Finally, to reduce the surface energy of the fabricated structures, the surfaces were chemically modified with perfluorooctyltrichlorosilane. Contact-angle measurements indicate that the micro-nano binary (MNB) hierarchical structures fabricated on the copper substrate became super-repellent toward a broad range of liquids with surface tension in the range of 21.5-72 mN/m. In an attempt to significantly improve the superoleophobic property of the surface, we also examined and compared the role of nanostructures in MNB hierarchical structures with only micro-fabricated surfaces. The fabricated MNB hierarchical structures also displays thermal stability and excellent long-term stability after exposure in air for more than 9 months. Our method might provide a general route toward the preparation of novel hierarchical films on metal substrates for various industrial applications.

  14. A flexible and stable surface-enhanced Raman scattering (SERS) substrate based on Au nanoparticles/Graphene oxide/Cicada wing array

    Science.gov (United States)

    Shi, Guochao; Wang, Mingli; Zhu, Yanying; Shen, Lin; Wang, Yuhong; Ma, Wanli; Chen, Yuee; Li, Ruifeng

    2018-04-01

    In this work, we presented an eco-friendly and low-cost method to fabricate a kind of flexible and stable Au nanoparticles/graphene oxide/cicada wing (AuNPs/GO/CW) substrate. By controlling the ratio of reactants, the optimum SERS substrate with average AuNPs size of 65 nm was obtained. The Raman enhancement factor for rhodamine 6G (R6G) was 1.08 ×106 and the limit of detection (LOD) was as low as 10-8 M. After calibrating the Raman peak intensities of R6G, it could be quantitatively detected. In order to better understand the experimental results, the 3D finite-different time-domain simulation was used to simulate the AuNPs/GO/CW-1 (the diameter of the AuNPs was 65 nm) to further investigate the SERS enhancement effect. More importantly, the AuNPs/GO/CW-1 substrates not only can provide strong enhancement factors but also can be stable and reproducible. This SERS substrates owned a good stability for the SERS intensity which was reduced only by 25% after the aging time of 60 days and the relative standard deviation was lower than 20%, revealing excellent uniformity and reproducibility. Our positive findings can pave a new way to optimize the application of SERS substrate as well as provide more SERS platforms for quantitative detection of organic contaminants vestige, which makes it very promising in the trace detection of biological molecules.

  15. Stable Isotope Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Tissue samples (skin, bone, blood, muscle) are analyzed for stable carbon, stable nitrogen, and stable sulfur analysis. Many samples are used in their entirety for...

  16. Demonstration of Li-based alloy coatings as low-voltage stable electron-emission surfaces for field-emission devices

    International Nuclear Information System (INIS)

    Auciello, O.; Krauss, A.R.; Gruen, D.M.; Shah, P.; Corrigan, T.; Kordesch, M.E.; Chang, R.P.; Barr, T.L.

    1999-01-01

    Alkali metals have extremely low work functions and are, therefore, expected to result in significant enhancement of the electron emission if they are used as coatings on Mo or Si microtip field-emission arrays (FEAs). However, the alkali metals are physically and chemically unstable in layers exceeding a few Angstrom in thickness. Maximum enhancement of electron emission occurs for alkali - metal layers 0.5 - 1 ML thick, but it is extremely difficult to fabricate and maintain such a thin alkali - metal coating. We present here an alternative means of producing chemically and thermally stable, self-replenishing lithium coatings approximately 1 ML thick, which results in a 13-fold reduction in the threshold voltage for electron emission compared with uncoated Si FEAs. copyright 1999 American Institute of Physics

  17. Using stable isotopes to assess surface water source dynamics and hydrological connectivity in a high-latitude wetland and permafrost influenced landscape

    Science.gov (United States)

    Ala-aho, P.; Soulsby, C.; Pokrovsky, O. S.; Kirpotin, S. N.; Karlsson, J.; Serikova, S.; Vorobyev, S. N.; Manasypov, R. M.; Loiko, S.; Tetzlaff, D.

    2018-01-01

    Climate change is expected to alter hydrological and biogeochemical processes in high-latitude inland waters. A critical question for understanding contemporary and future responses to environmental change is how the spatio-temporal dynamics of runoff generation processes will be affected. We sampled stable water isotopes in soils, lakes and rivers on an unprecedented spatio-temporal scale along a 1700 km transect over three years in the Western Siberia Lowlands. Our findings suggest that snowmelt mixes with, and displaces, large volumes of water stored in the organic soils and lakes to generate runoff during the thaw season. Furthermore, we saw a persistent hydrological connection between water bodies and the landscape across permafrost regions. Our findings help to bridge the understanding between small and large scale hydrological studies in high-latitude systems. These isotope data provide a means to conceptualise hydrological connectivity in permafrost and wetland influenced regions, which is needed for an improved understanding of future biogeochemical changes.

  18. The skin migratory stage of the schistosomulum of Schistosoma mansoni has a surface showing greater permeability and activity in membrane internalisation than other forms of skin or mechanical schistosomula.

    Science.gov (United States)

    DE Jesus Jeremias, Wander; DA Cunha Melo, Jose Renan; Baba, Elio Hideo; Coelho, Paulo Marcos Zech; Kusel, John Robert

    2015-08-01

    Skin schistosomula can be prepared by collecting them after isolated mouse skin have been penetrated by cercariae in vitro. The schistosomula can also migrate out of isolated mouse skin penetrated by cercariae in vitro and from mouse skin penetrated by cercariae in vivo. Schistosomula can also be produced from cercariae applied through a syringe or in a vortex. When certain surface properties of the different forms of schistosomula were compared, those migrating from mouse skin penetrated by cercariae in vivo or in vitro had greatly increased permeability to membrane impermeant molecules such as Lucifer yellow and high molecular weight dextrans. These migrating forms also possessed surfaces which showed greatly enhanced uptake into internal membrane vesicles of the dye FM 143, a marker for endocytosis. This greatly enhanced activity and permeability of the surfaces of tissue migrating schistosomula is likely to be of great importance in the adaptation to the new host.

  19. Geochemistry of organic carbon and nitrogen in surface sediments of coastal Bohai Bay inferred from their ratios and stable isotopic signatures

    International Nuclear Information System (INIS)

    Gao Xuelu; Yang Yuwei; Wang Chuanyuan

    2012-01-01

    Total organic carbon (TOC), total nitrogen (TN) and their δ 13 C and δ 15 N values were determined for 42 surface sediments from coastal Bohai Bay in order to determine the concentration and identify the source of organic matter. The sampling sites covered both the marine region of coastal Bohai Bay and the major rivers it connects with. More abundant TOC and TN in sediments from rivers than from the marine region reflect the situation that most of the terrestrial organic matter is deposited before it meets the sea. The spatial variation in δ 13 C and δ 15 N signatures implies that the input of organic matter from anthropogenic activities has a more significant influence on its distribution than that from natural processes. Taking the area as a whole, surface sediments in the marine region of coastal Bohai Bay are dominated by marine derived organic carbon, which on average accounts for 62 ± 11% of TOC.

  20. Surface enrichment of Pt in stable Pt-Ir nano-alloy particles on MgAl 2 O 4 spinel in oxidizing atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Li, Weizhen; Nie, Lei; Chen, Ying; Kovarik, Libor; Liu, Jun; Wang, Yong

    2017-04-01

    With the capability of MgAl2O4 spinel {111} nano-facets in stabilizing small Rh, Ir and Pt particles, bimetallic Ir-Pt catalysts on the same support were investigated, aiming at further lowering the catalyst cost by substituting expensive Pt with cheaper Ir in the bulk. Small Pt-Ir nano-alloy particles (< 2nm) were successfully stabilized on the spinel {111} nano-facets as expected. Interestingly, methanol oxidative dehydrogenation (ODH) rate on the surface Pt atoms increases with oxidizing aging but decreases upon reducing treatment, where Ir is almost inactive under the same reaction conditions. Up to three times enhancement in Pt exposure was achieved when the sample was oxidized at 800 °C in air for 1 week and subsequently reduced by H2 for 2 h, demonstrating successful surface enrichment of Pt on Pt-Ir nano-alloy particles. A dynamic stabilization mechanism involving wetting\

  1. New insight in the structural features of haloadaptation in α-amylases from halophilic Archaea following homology modeling strategy: folded and stable conformation maintained through low hydrophobicity and highly negative charged surface

    Science.gov (United States)

    Zorgani, Mohamed Amine; Patron, Kevin; Desvaux, Mickaël

    2014-07-01

    Proteins from halophilic archaea, which live in extreme saline conditions, have evolved to remain folded, active and stable at very high ionic strengths. Understanding the mechanism of haloadaptation is the first step toward engineering of halostable biomolecules. Amylases are one of the main enzymes used in industry. Yet, no three-dimensional structure has been experimentally resolved for α-amylases from halophilic archaea. In this study, homology structure modeling of α-amylases from the halophilic archaea Haloarcula marismortui, Haloarcula hispanica, and Halalkalicoccus jeotgali were performed. The resulting models were subjected to energy minimization, evaluation, and structural analysis. Calculations of the amino acid composition, salt bridges and hydrophobic interactions were also performed and compared to a set of non-halophilic counterparts. It clearly appeared that haloarchaeal α-amylases exhibited lower propensities for helix formation and higher propensities for coil-forming regions. Furthermore, they could maintain a folded and stable conformation in high salt concentration through highly negative charged surface with over representation of acidic residues, especially Asp, and low hydrophobicity with increase of salt bridges and decrease in hydrophobic interactions on the protein surface. This study sheds some light on the stability of α-amylases from halophilic archaea and provides strong basis not only to understand haloadaptation mechanisms of proteins in microorganisms from hypersalines environments but also for biotechnological applications.

  2. Stable rotating dipole solitons in nonlocal media

    DEFF Research Database (Denmark)

    Lopez-Aguayo, Servando; Skupin, Stefan; Desyatnikov, Anton S.

    2006-01-01

    We present the first example of stable rotating two-soliton bound states in nonlinear optical media with nonlocal response. We show that, in contrast to media with local response, nonlocality opens possibilities to generate stable azimuthons.......We present the first example of stable rotating two-soliton bound states in nonlinear optical media with nonlocal response. We show that, in contrast to media with local response, nonlocality opens possibilities to generate stable azimuthons....

  3. Stable convergence and stable limit theorems

    CERN Document Server

    Häusler, Erich

    2015-01-01

    The authors present a concise but complete exposition of the mathematical theory of stable convergence and give various applications in different areas of probability theory and mathematical statistics to illustrate the usefulness of this concept. Stable convergence holds in many limit theorems of probability theory and statistics – such as the classical central limit theorem – which are usually formulated in terms of convergence in distribution. Originated by Alfred Rényi, the notion of stable convergence is stronger than the classical weak convergence of probability measures. A variety of methods is described which can be used to establish this stronger stable convergence in many limit theorems which were originally formulated only in terms of weak convergence. Naturally, these stronger limit theorems have new and stronger consequences which should not be missed by neglecting the notion of stable convergence. The presentation will be accessible to researchers and advanced students at the master's level...

  4. Stable configurations in social networks

    Science.gov (United States)

    Bronski, Jared C.; DeVille, Lee; Ferguson, Timothy; Livesay, Michael

    2018-06-01

    We present and analyze a model of opinion formation on an arbitrary network whose dynamics comes from a global energy function. We study the global and local minimizers of this energy, which we call stable opinion configurations, and describe the global minimizers under certain assumptions on the friendship graph. We show a surprising result that the number of stable configurations is not necessarily monotone in the strength of connection in the social network, i.e. the model sometimes supports more stable configurations when the interpersonal connections are made stronger.

  5. Pharmaceuticals labelled with stable isotopes

    International Nuclear Information System (INIS)

    Krumbiegel, P.

    1986-11-01

    The relatively new field of pharmaceuticals labelled with stable isotopes is reviewed. Scientific, juridical, and ethical questions are discussed concerning the application of these pharmaceuticals in human medicine. 13 C, 15 N, and 2 H are the stable isotopes mainly utilized in metabolic function tests. Methodical contributions are given to the application of 2 H, 13 C, and 15 N pharmaceuticals showing new aspects and different states of development in the field under discussion. (author)

  6. Determination of physical and dynamic properties of suspended particles in water column with ultrasonic scanning in between the water surface and stable sediment layer.

    Science.gov (United States)

    Acar, Dursun; Alpar, Bedri; Ozeren, Sinan; Cagatay, Namık; Sari, Erol; Vardar, Denizhan; Eris, Kadir

    2015-04-01

    The behavior of seafloor sediment with its water column should be known against any occurrences of anoxic or oxic conditions. The most important ones of these conditions are possible leakage of natural gas or escape of liquids from sediment. On the basis of combined solid/liquid flow dynamics in sedimentation, such kind of events can change, even in an effective manner, the dynamic movements of molecules and their cumulative mass of particules, i.e. the suspended materials. The deployment of suitable sediment traps or ultrasonic transducers somewhere in the water column are not easy attempts in order to obtain useful information about the state of suspended materials during sedimentation. These are usually bulky instruments; therefore they may behave like an anti-move suppresser on the particles moving in the float direction, in oxic and anoxic manner. These instruments, on the other hand, may cover the effects of diffusive flow or bubble formed gas and fluid escape from the sediment surface into the water column. Ultrasonic scanners, however, are able to make observations in a remote manner, without affecting such artificial events. Our field trials were successfully completed at the historical estuary called Halic of Marmara sea . The physical properties; such as the velocity of particles, their travel directions, their dimensions and the ability to observe anti-compositor crushes of shock waves of the bubbles are only a few of these observations in natural ambience. The most important problem solved about water pressure during 3 atmosphere . The sensor has been tested successfully few times. We used the ''High voltage electric isolator oil filling'' to the inside of the scanner for pressure equalization between outer side and inner body of probe at a depth of (20 meters) beneath the sea surface . The transmitted signals by the planar crystal of the transducer become weaker under the pressure of overlying water column in depths. Our efforts are now focused on the

  7. The Myopic Stable Set for Social Environments

    NARCIS (Netherlands)

    Demuynck, Thomas; Herings, P. Jean-Jacques; Saulle, Riccardo; Seel, Christian

    2017-01-01

    We introduce a new solution concept for models of coalition formation, called the myopic stable set. The myopic stable set is defined for a very general class of social environments and allows for an infinite state space. We show that the myopic stable set exists and is non-empty. Under minor

  8. stableGP

    Data.gov (United States)

    National Aeronautics and Space Administration — The code in the stableGP package implements Gaussian process calculations using efficient and numerically stable algorithms. Description of the algorithms is in the...

  9. Angina Pectoris (Stable Angina)

    Science.gov (United States)

    ... Peripheral Artery Disease Venous Thromboembolism Aortic Aneurysm More Angina Pectoris (Stable Angina) Updated:Aug 21,2017 You may have heard the term “angina pectoris” or “stable angina” in your doctor’s office, ...

  10. Hyperspectral surface materials map of quadrangles 3664 and 3764, Char Shengo (123), Shibirghan (124), Jalajin (117), and Kham-Ab (118) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  11. Hyperspectral surface materials map of quadrangles 3666 and 3766, Balkh (219), Mazar-e Sharif (220), Qarqin (213), and Hazara Toghai (214) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  12. Hyperspectral surface materials map of quadrangles 3668 and 3768, Baghlan (221), Taluqan (222), Imam Sahib (215), and Rustaq (216) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  13. Hyperspectral surface materials map of quadrangles 2962 and 3062, Gawdezereh (615), Galachah (616), Chahar Burjak (609), and Khan Neshin (610) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    Hoefen, Todd M.; King, Trude V.V.; Kokaly, Raymond F.; Livo, Keith E.; Giles, Stuart A.; Johnson, Michaela R.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  14. Hyperspectral surface materials map of quadrangles 3360 and 3460, Kawir-e Naizar (413), Kohe-Mahmudo-Esmailjan (414), Kol-e Namaksar (407), and Ghoriyan (408) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan.Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines.The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  15. On the stability of a rod adhering to a rigid surface: Shear-induced stable adhesion and the instability of peeling

    Science.gov (United States)

    Majidi, Carmel; O'Reilly, Oliver M.; Williams, John A.

    2012-05-01

    Using variational methods, we establish conditions for the nonlinear stability of adhesive states between an elastica and a rigid halfspace. The treatment produces coupled criteria for adhesion and buckling instabilities by exploiting classical techniques from Legendre and Jacobi. Three examples that arise in a broad range of engineered systems, from microelectronics to biologically inspired fiber array adhesion, are used to illuminate the stability criteria. The first example illustrates buckling instabilities in adhered rods, while the second shows the instability of a peeling process and the third illustrates the stability of a shear-induced adhesion. The latter examples can also be used to explain how microfiber array adhesives can be activated by shearing and deactivated by peeling. The nonlinear stability criteria developed in this paper are also compared to other treatments.

  16. Modelling stable atmospheric boundary layers over snow

    NARCIS (Netherlands)

    Sterk, H.A.M.

    2015-01-01

    Thesis entitled:

    Modelling Stable Atmospheric Boundary Layers over Snow

    H.A.M. Sterk

    Wageningen, 29th of April, 2015

    Summary

    The emphasis of this thesis is on the understanding and forecasting of the Stable Boundary Layer (SBL) over snow-covered surfaces. SBLs

  17. Air-Stable Surface-Passivated Perovskite Quantum Dots for Ultra-Robust, Single- and Two-Photon-Induced Amplified Spontaneous Emission

    KAUST Repository

    Pan, Jun

    2015-12-01

    We demonstrate ultra-air- and photostable CsPbBr3 quantum dots (QDs) by using an inorganic–organic hybrid ion pair as the capping ligand. This passivation approach to perovskite QDs yields high photoluminescence quantum yield with unprecedented operational stability in ambient conditions (60 ± 5% lab humidity) and high pump fluences, thus overcoming one of the greatest challenges impeding the development of perovskite-based applications. Due to the robustness of passivated perovskite QDs, we were able to induce ultrastable amplified spontaneous emission (ASE) in solution processed QD films not only through one photon but also through two-photon absorption processes. The latter has not been observed before in the family of perovskite materials. More importantly, passivated perovskite QD films showed remarkable photostability under continuous pulsed laser excitation in ambient conditions for at least 34 h (corresponds to 1.2 × 108 laser shots), substantially exceeding the stability of other colloidal QD systems in which ASE has been observed.

  18. Show-Bix &

    DEFF Research Database (Denmark)

    2014-01-01

    The anti-reenactment 'Show-Bix &' consists of 5 dias projectors, a dial phone, quintophonic sound, and interactive elements. A responsive interface will enable the Dias projectors to show copies of original dias slides from the Show-Bix piece ”March på Stedet”, 265 images in total. The copies are...

  19. Stable isotopes labelled compounds

    International Nuclear Information System (INIS)

    1982-09-01

    The catalogue on stable isotopes labelled compounds offers deuterium, nitrogen-15, and multiply labelled compounds. It includes: (1) conditions of sale and delivery, (2) the application of stable isotopes, (3) technical information, (4) product specifications, and (5) the complete delivery programme

  20. Evolutionary Stable Strategy

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 21; Issue 9. Evolutionary Stable Strategy: Application of Nash Equilibrium in Biology. General Article Volume 21 Issue 9 September 2016 pp 803- ... Keywords. Evolutionary game theory, evolutionary stable state, conflict, cooperation, biological games.

  1. Talking with TV shows

    DEFF Research Database (Denmark)

    Sandvik, Kjetil; Laursen, Ditte

    2014-01-01

    User interaction with radio and television programmes is not a new thing. However, with new cross-media production concepts such as X Factor and Voice, this is changing dramatically. The second-screen logic of these productions encourages viewers, along with TV’s traditional one-way communication...... mode, to communicate on interactive (dialogue-enabling) devices such as laptops, smartphones and tablets. Using the TV show Voice as our example, this article shows how the technological and situational set-up of the production invites viewers to engage in new ways of interaction and communication...

  2. Water-stable diblock polystyrene-block-poly(2-vinyl pyridine) and diblock polystyrene-block-poly(methyl methacrylate) cylindrical patterned surfaces inhibit settlement of zoospores of the green alga Ulva.

    Science.gov (United States)

    Grozea, Claudia M; Gunari, Nikhil; Finlay, John A; Grozea, Daniel; Callow, Maureen E; Callow, James A; Lu, Zheng-Hong; Walker, Gilbert C

    2009-04-13

    Nanopatterned surfaces with hydrophobic and hydrophilic domains were produced using the diblock copolymer polystyrene-block-poly(2-vinyl pyridine) (PS-b-P2VP) and polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA). The PS-b-P2VP diblock copolymer, mixed with the cross-linker benzophenone and spin-coated onto silicon wafers, showed self-assembled cylindrical structures, which were retained after UV treatment for cross-linking. The thin films displayed cylindrical domains after immersion in water. This study shows that pattern retention in water is possible for a long period of time, at least for two weeks in pure water and three weeks in artificial seawater. The PS-b-PMMA diblock showed self-assembled cylindrical structures. PS-b-P2VP and PS-b-PMMA cylindrical patterned surfaces showed reduced settlement of zoospores of the green alga Ulva compared to unpatterned surfaces. The copolymers were investigated using atomic force microscopy and X-ray photoelectron spectroscopy.

  3. Talk Show Science.

    Science.gov (United States)

    Moore, Mitzi Ruth

    1992-01-01

    Proposes having students perform skits in which they play the roles of the science concepts they are trying to understand. Provides the dialog for a skit in which hot and cold gas molecules are interviewed on a talk show to study how these properties affect wind, rain, and other weather phenomena. (MDH)

  4. Obesity in show cats.

    Science.gov (United States)

    Corbee, R J

    2014-12-01

    Obesity is an important disease with a high prevalence in cats. Because obesity is related to several other diseases, it is important to identify the population at risk. Several risk factors for obesity have been described in the literature. A higher incidence of obesity in certain cat breeds has been suggested. The aim of this study was to determine whether obesity occurs more often in certain breeds. The second aim was to relate the increased prevalence of obesity in certain breeds to the official standards of that breed. To this end, 268 cats of 22 different breeds investigated by determining their body condition score (BCS) on a nine-point scale by inspection and palpation, at two different cat shows. Overall, 45.5% of the show cats had a BCS > 5, and 4.5% of the show cats had a BCS > 7. There were significant differences between breeds, which could be related to the breed standards. Most overweight and obese cats were in the neutered group. It warrants firm discussions with breeders and cat show judges to come to different interpretations of the standards in order to prevent overweight conditions in certain breeds from being the standard of beauty. Neutering predisposes for obesity and requires early nutritional intervention to prevent obese conditions. Journal of Animal Physiology and Animal Nutrition © 2014 Blackwell Verlag GmbH.

  5. Honored Teacher Shows Commitment.

    Science.gov (United States)

    Ratte, Kathy

    1987-01-01

    Part of the acceptance speech of the 1985 National Council for the Social Studies Teacher of the Year, this article describes the censorship experience of this honored social studies teacher. The incident involved the showing of a videotape version of the feature film entitled "The Seduction of Joe Tynan." (JDH)

  6. Population Games, Stable Games, and Passivity

    Directory of Open Access Journals (Sweden)

    Michael J. Fox

    2013-10-01

    Full Text Available The class of “stable games”, introduced by Hofbauer and Sandholm in 2009, has the attractive property of admitting global convergence to equilibria under many evolutionary dynamics. We show that stable games can be identified as a special case of the feedback-system-theoretic notion of a “passive” dynamical system. Motivated by this observation, we develop a notion of passivity for evolutionary dynamics that complements the definition of the class of stable games. Since interconnections of passive dynamical systems exhibit stable behavior, we can make conclusions about passive evolutionary dynamics coupled with stable games. We show how established evolutionary dynamics qualify as passive dynamical systems. Moreover, we exploit the flexibility of the definition of passive dynamical systems to analyze generalizations of stable games and evolutionary dynamics that include forecasting heuristics as well as certain games with memory.

  7. The energy show

    International Nuclear Information System (INIS)

    1988-01-01

    The Energy Show is a new look at the problems of world energy, where our supplies come from, now and in the future. The programme looks at how we need energy to maintain our standards of living. Energy supply is shown as the complicated set of problems it is - that Fossil Fuels are both raw materials and energy sources, that some 'alternatives' so readily suggested as practical options are in reality a long way from being effective. (author)

  8. Normal modified stable processes

    DEFF Research Database (Denmark)

    Barndorff-Nielsen, Ole Eiler; Shephard, N.

    2002-01-01

    Gaussian (NGIG) laws. The wider framework thus established provides, in particular, for added flexibility in the modelling of the dynamics of financial time series, of importance especially as regards OU based stochastic volatility models for equities. In the special case of the tempered stable OU process......This paper discusses two classes of distributions, and stochastic processes derived from them: modified stable (MS) laws and normal modified stable (NMS) laws. This extends corresponding results for the generalised inverse Gaussian (GIG) and generalised hyperbolic (GH) or normal generalised inverse...

  9. Applications of stable isotopes

    International Nuclear Information System (INIS)

    Letolle, R.; Mariotti, A.; Bariac, T.

    1991-06-01

    This report reviews the historical background and the properties of stable isotopes, the methods used for their measurement (mass spectrometry and others), the present technics for isotope enrichment and separation, and at last the various present and foreseeable application (in nuclear energy, physical and chemical research, materials industry and research; tracing in industrial, medical and agronomical tests; the use of natural isotope variations for environmental studies, agronomy, natural resources appraising: water, minerals, energy). Some new possibilities in the use of stable isotope are offered. A last chapter gives the present state and forecast development of stable isotope uses in France and Europe

  10. Analysing Stable Time Series

    National Research Council Canada - National Science Library

    Adler, Robert

    1997-01-01

    We describe how to take a stable, ARMA, time series through the various stages of model identification, parameter estimation, and diagnostic checking, and accompany the discussion with a goodly number...

  11. Showing Value (Editorial

    Directory of Open Access Journals (Sweden)

    Denise Koufogiannakis

    2009-06-01

    Full Text Available When Su Cleyle and I first decided to start Evidence Based Library and Information Practice, one of the things we agreed upon immediately was that the journal be open access. We knew that a major obstacle to librarians using the research literature was that they did not have access to the research literature. Although Su and I are both academic librarians who can access a wide variety of library and information literature from our institutions, we belong to a profession where not everyone has equal access to the research in our field. Without such access to our own body of literature, how can we ever hope for practitioners to use research evidence in their decision making? It would have been contradictory to the principles of evidence based library and information practice to do otherwise.One of the specific groups we thought could use such an open access venue for discovering research literature was school librarians. School librarians are often isolated and lacking access to the research literature that may help them prove to stakeholders the importance of their libraries and their role within schools. Certainly, school libraries have been in decline and the use of evidence to show value is needed. As Ken Haycock noted in his 2003 report, The Crisis in Canada’s School Libraries: The Case for Reform and Reinvestment, “Across the country, teacher-librarians are losing their jobs or being reassigned. Collections are becoming depleted owing to budget cuts. Some principals believe that in the age of the Internet and the classroom workstation, the school library is an artifact” (9. Within this context, school librarians are looking to our research literature for evidence of the impact that school library programs have on learning outcomes and student success. They are integrating that evidence into their practice, and reflecting upon what can be improved locally. They are focusing on students and showing the impact of school libraries and

  12. Uses of stable isotopes

    International Nuclear Information System (INIS)

    Axente, Damian

    1998-01-01

    The most important fields of stable isotope use with examples are presented. These are: 1. Isotope dilution analysis: trace analysis, measurements of volumes and masses; 2. Stable isotopes as tracers: transport phenomena, environmental studies, agricultural research, authentication of products and objects, archaeometry, studies of reaction mechanisms, structure and function determination of complex biological entities, studies of metabolism, breath test for diagnostic; 3. Isotope equilibrium effects: measurement of equilibrium effects, investigation of equilibrium conditions, mechanism of drug action, study of natural processes, water cycle, temperature measurements; 4. Stable isotope for advanced nuclear reactors: uranium nitride with 15 N as nuclear fuel, 157 Gd for reactor control. In spite of some difficulties of stable isotope use, particularly related to the analytical techniques, which are slow and expensive, the number of papers reporting on this subject is steadily growing as well as the number of scientific meetings organized by International Isotope Section and IAEA, Gordon Conferences, and regional meeting in Germany, France, etc. Stable isotope application development on large scale is determined by improving their production technologies as well as those of labeled compound and the analytical techniques. (author)

  13. An inexpensive and simple method for thermally stable immobilization of DNA on an unmodified glass surface: UV linking of poly(T)10-poly(C)10-tagged DNA probes

    DEFF Research Database (Denmark)

    Guðnason, Haukur; Dufva, Hans Martin; Bang, Dang Duong

    2008-01-01

    be linked by UV light irradiation onto a plain, unmodified glass surface. Probes immobilized onto unmodified glass microscope slides performed similarly to probes bound to commercial amino-silane-coated slides and had comparable detection limits. The TC-tagged probes linked to unmodified glass did not show...... any significant decrease in hybridization performance after a 20 min incubation in water at 100 degrees C prior to rehybridization, indicating a covalent bond between the TC tag and unmodified glass. The probes were used in thermal minisequencing cycling reactions. Furthermore, the TC tag improved...

  14. Stable-isotope paleoclimatology

    International Nuclear Information System (INIS)

    Deuser, W.G.

    1978-01-01

    Seasonal variations of temperature and salinity in the surface waters of large parts of the oceans are well established. Available data on seasonal distributions of planktonic foraminifera show that the abundances of different species groups peak at different times of the year with an apparent succession of abundance peaks through most of the year. This evidence suggests that a measure of seasonal contrast is recorded in the isotope ratios of oxygen, and perhaps carbon, in the tests of different foraminiferal species. The evaluation of this potential paleoclimatologic tool awaits planned experiments with recent foraminifera in well-known settings, but a variety of available data is consistent with the idea that interspecies differences in 18 O content contain a seasonal component.(auth.)

  15. Stable isotope studies

    International Nuclear Information System (INIS)

    Ishida, T.

    1992-01-01

    The research has been in four general areas: (1) correlation of isotope effects with molecular forces and molecular structures, (2) correlation of zero-point energy and its isotope effects with molecular structure and molecular forces, (3) vapor pressure isotope effects, and (4) fractionation of stable isotopes. 73 refs, 38 figs, 29 tabs

  16. Interactive Stable Ray Tracing

    DEFF Research Database (Denmark)

    Dal Corso, Alessandro; Salvi, Marco; Kolb, Craig

    2017-01-01

    Interactive ray tracing applications running on commodity hardware can suffer from objectionable temporal artifacts due to a low sample count. We introduce stable ray tracing, a technique that improves temporal stability without the over-blurring and ghosting artifacts typical of temporal post-pr...

  17. The Stable Concordance Genus

    OpenAIRE

    Kearney, M. Kate

    2013-01-01

    The concordance genus of a knot is the least genus of any knot in its concordance class. Although difficult to compute, it is a useful invariant that highlights the distinction between the three-genus and four-genus. In this paper we define and discuss the stable concordance genus of a knot, which describes the behavior of the concordance genus under connected sum.

  18. Stable radiographic scanning agents

    International Nuclear Information System (INIS)

    1976-01-01

    Stable compositions which are useful in the preparation of Technetium-99m-based scintigraphic agents are discussed. They are comprised of ascorbic acid or a pharmaceutically acceptable salt or ester thereof in combination with a pertechnetate reducing agent or dissolved in oxidized pertechnetate-99m (sup(99m)TcO 4 - ) solution

  19. Some stable hydromagnetic equilibria

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, J L; Oberman, C R; Kulsrud, R M; Frieman, E A [Project Matterhorn, Princeton University, Princeton, NJ (United States)

    1958-07-01

    We have been able to find and investigate the properties of equilibria which are hydromagnetically stable. These equilibria can be obtained, for example, by wrapping conductors helically around the stellarator tube. Systems with I = 3 or 4 are indicated to be optimum for stability purposes. In some cases an admixture of I = 2 fields can be advantageous for achieving equilibrium. (author)

  20. Factors controlling stable isotope composition of European precipitation

    International Nuclear Information System (INIS)

    Rozanski, K.; Sonntag, C.; Muennich, K.O.

    1982-01-01

    The seasonal and spatial variations of stable isotope ratios in present day European precipitation are simulated with a simple multibox model of the mean west-east horizontal transport of the atmospheric water vapour across the European continent. Isotope fractionation during the formation of precipitation leads to an increasing depletion of heavy isotopes in the residual air moisture as it moves towards the centre of the continent. This isotopic depletion is partly compensated, particularly in summer, by evapotranspiration, which is assumed to transfer soil water into the atmosphere without isotope fractionation. The model estimates are based on horizontal water vapour flux data, varying seasonally between 88 and 130 kg m -1 s -1 for the Atlantic coast region, and on the monthly precipitation, evapotranspiration and surface air temperature data available for various locations in Europe. Both continental and seasonal temperature effects observed in the stable isotope composition of European precipitation are fairly well reproduced by the model. The calculations show that the isotopic composition of local precipitation is primarily controlled by regional scale processes, i.e. by the water vapour transport patterns into the continent, and by the average precipitation-evapotranspiration history of the air masses precipitating at a given place. Local parameters such as the surface and/or cloud base temperature or the amount of precipitation modify the isotope ratios only slightly. Implications of the model predictions for the interpretation of stable isotope ratios in earlier periods as they are preserved in ice cores and in groundwater are also discussed. (Auth.)

  1. Deposition of radionuclides and stable elements in Tokai-mura

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, Takashi; Amano, Hikaru [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2003-03-01

    This report presents the data of deposition of radionuclides (Sep. 1993-March 2001) and stable elements (Sep. 1993-Oct. 1995) in Tokai-mura. To evaluate the migration of radionuclides and stable elements from the atmosphere to the ground surface, atmospheric deposition samples were collected from Sep. 1993 to March 2001 with three basins (distance to grand surface were 1.5 m, 4 m, 10 m) set up in the enclosure of JAERI in Tokai-mura, Ibaraki-ken, Japan. Monthly samples were evaporated to dryness to obtain residual samples and measured with a well type Ge detector for {sup 7}Be, {sup 40}K, {sup 137}Cs and {sup 210}Pb. According to the analysis of radioactivity, clear seasonal variations with spring peaks of deposition weight (dry) and deposition amounts of all objective radionuclides were found. Correlation analysis of deposition data also showed that these radionuclides can be divided into two groups. A part of dried sample was irradiated to reactor neutrons at JRR-4 for determination of stable element's deposition. (author)

  2. Stable isotope analysis

    International Nuclear Information System (INIS)

    Tibari, Elghali; Taous, Fouad; Marah, Hamid

    2014-01-01

    This report presents results related to stable isotopes analysis carried out at the CNESTEN DASTE in Rabat (Morocco), on behalf of Senegal. These analyzes cover 127 samples. These results demonstrate that Oxygen-18 and Deuterium in water analysis were performed by infrared Laser spectroscopy using a LGR / DLT-100 with Autosampler. Also, the results are expressed in δ values (‰) relative to V-SMOW to ± 0.3 ‰ for oxygen-18 and ± 1 ‰ for deuterium.

  3. Forensic Stable Isotope Biogeochemistry

    Science.gov (United States)

    Cerling, Thure E.; Barnette, Janet E.; Bowen, Gabriel J.; Chesson, Lesley A.; Ehleringer, James R.; Remien, Christopher H.; Shea, Patrick; Tipple, Brett J.; West, Jason B.

    2016-06-01

    Stable isotopes are being used for forensic science studies, with applications to both natural and manufactured products. In this review we discuss how scientific evidence can be used in the legal context and where the scientific progress of hypothesis revisions can be in tension with the legal expectations of widely used methods for measurements. Although this review is written in the context of US law, many of the considerations of scientific reproducibility and acceptance of relevant scientific data span other legal systems that might apply different legal principles and therefore reach different conclusions. Stable isotopes are used in legal situations for comparing samples for authenticity or evidentiary considerations, in understanding trade patterns of illegal materials, and in understanding the origins of unknown decedents. Isotope evidence is particularly useful when considered in the broad framework of physiochemical processes and in recognizing regional to global patterns found in many materials, including foods and food products, drugs, and humans. Stable isotopes considered in the larger spatial context add an important dimension to forensic science.

  4. In situ controllable synthesis of novel surface plasmon resonance-enhanced Ag{sub 2}WO{sub 4}/Ag/Bi{sub 2}MoO{sub 6} composite for enhanced and stable visible light photocatalyst

    Energy Technology Data Exchange (ETDEWEB)

    Lv, Jiali [College of Physics and Electronic Information, Huaibei Normal University, Huaibei 235000 (China); Dai, Kai, E-mail: daikai940@chnu.edu.cn [College of Physics and Electronic Information, Huaibei Normal University, Huaibei 235000 (China); Zhang, Jinfeng [College of Physics and Electronic Information, Huaibei Normal University, Huaibei 235000 (China); Lu, Luhua, E-mail: lhlu@cug.edu.cn [Engineering Research Center of Nano-Geomaterials of Ministry of Education, China University of Geosciences, Wuhan 430074 (China); Liang, Changhao, E-mail: chliang@issp.ac.cn [College of Physics and Electronic Information, Huaibei Normal University, Huaibei 235000 (China); Key Laboratory of Materials Physics and Anhui Key Laboratory of Nanomaterials and Nanotechnology, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 23003 (China); Geng, Lei; Wang, Zhongliao; Yuan, Guangyu; Zhu, Guangping [College of Physics and Electronic Information, Huaibei Normal University, Huaibei 235000 (China)

    2017-01-01

    Highlights: • Novel Ag{sub 2}WO{sub 4}/Ag/Bi{sub 2}MoO{sub 6} ternary photocatalyst was prepared. • Ag{sub 2}WO{sub 4}/Ag/Bi{sub 2}MoO{sub 6} showed enhanced catalytic activity. • Ag{sub 2}WO{sub 4}/Ag/Bi{sub 2}MoO{sub 6} showed long reusable life. - Abstract: A novel hierarchical Ag{sub 2}WO{sub 4}/Ag/Bi{sub 2}MoO{sub 6} ternary visible-light-driven photocatalyst was successfully synthesized by in situ doping Ag{sub 2}WO{sub 4} with Bi{sub 2}MoO{sub 6} nanosheets through a facile hydrothermal and photochemical process. The morphology, structure, optical performance and crystallinity of the products were measured by field emission scanning electron microscope (FESEM), energy dispersive spectrometer (EDS), UV–vis diffuse reflectance spectroscopy (DRS) and X-ray diffraction (XRD). The results showed that Ag{sub 2}WO{sub 4}/Ag was uniformly dispersed on the surface of Bi{sub 2}MoO{sub 6} nanosheets. The photocatalytic performance of Ag{sub 2}WO{sub 4}/Ag/Bi{sub 2}MoO{sub 6} heterostructures was evaluated by the degradation of methylene blue (MB) under 410 nm LED arrays. The ternary Ag{sub 2}WO{sub 4}/Ag/Bi{sub 2}MoO{sub 6} nanocomposite exhibits higher photocatalytic activity than Bi{sub 2}MoO{sub 6} and Ag{sub 2}WO{sub 4}. The synergistic effect of Ag{sub 2}WO{sub 4} and Bi{sub 2}MoO{sub 6} could generated more heterojunctions which promoted photoelectrons transfer from Ag{sub 2}WO{sub 4} to Bi{sub 2}MoO{sub 6}, leading to the improvement of photocatalytic performance by photoelectrons-holes recombination suppression. At the same time, the surface plasmon resonance of Ag{sub 2}WO{sub 4}/Ag/Bi{sub 2}MoO{sub 6} is another crucial reason for the high photocatalytic performance of organic pollutants degradation. And the 20 wt% Ag{sub 2}WO{sub 4}-loaded Bi{sub 2}MoO{sub 6} shows the optimal photocatalytic performance in the degradation of MB. In addition, the ternary composites can be easily reclaimed by precipitation and exhibits high stability of photocatalytic

  5. Ballooning stable high beta tokamak equilibria

    International Nuclear Information System (INIS)

    Tuda, Takashi; Azumi, Masafumi; Kurita, Gen-ichi; Takizuka, Tomonori; Takeda, Tatsuoki

    1981-04-01

    The second stable regime of ballooning modes is numerically studied by using the two-dimensional tokamak transport code with the ballooning stability code. Using the simple FCT heating scheme, we find that the plasma can locally enter this second stable regime. And we obtained equilibria with fairly high beta (β -- 23%) stable against ballooning modes in a whole plasma region, by taking into account of finite thermal diffusion due to unstable ballooning modes. These results show that a tokamak fusion reactor can operate in a high beta state, which is economically favourable. (author)

  6. Stable lithium electrodeposition in liquid and nanoporous solid electrolytes

    KAUST Repository

    Lu, Yingying

    2014-08-10

    Rechargeable lithium, sodium and aluminium metal-based batteries are among the most versatile platforms for high-energy, cost-effective electrochemical energy storage. Non-uniform metal deposition and dendrite formation on the negative electrode during repeated cycles of charge and discharge are major hurdles to commercialization of energy-storage devices based on each of these chemistries. A long-held view is that unstable electrodeposition is a consequence of inherent characteristics of these metals and their inability to form uniform electrodeposits on surfaces with inevitable defects. We report on electrodeposition of lithium in simple liquid electrolytes and in nanoporous solids infused with liquid electrolytes. We find that simple liquid electrolytes reinforced with halogenated salt blends exhibit stable long-term cycling at room temperature, often with no signs of deposition instabilities over hundreds of cycles of charge and discharge and thousands of operating hours. We rationalize these observations with the help of surface energy data for the electrolyte/lithium interface and impedance analysis of the interface during different stages of cell operation. Our findings provide support for an important recent theoretical prediction that the surface mobility of lithium is significantly enhanced in the presence of lithium halide salts. Our results also show that a high electrolyte modulus is unnecessary for stable electrodeposition of lithium.

  7. A systematic first-principles study of surface energies, surface relaxation and Friedel oscillation of magnesium surfaces

    International Nuclear Information System (INIS)

    Tang, Jia-Jun; Yang, Xiao-Bao; Zhao, Yu-Jun; OuYang, LiuZhang; Zhu, Min

    2014-01-01

    We systematically study the surface energies and surface relaxations of various low-index and high-index Mg surfaces. It is found that low-index surfaces are not necessarily stable as Mg(1 0  1-bar  0) is the most unstable surface in the series of Mg(1 0  1-bar  n) (n = 0–9). A surface-energy predicting model based on the bond cutting is proposed to explain the relative surface stabilities. The local relaxations of the low-index surfaces could be explained by the Friedel oscillation. For the high-index surfaces, the combination of charge smoothing effect and dramatic charge depletion influences the relaxations, which show a big difference from the low-index ones. Our findings provide theoretical data for considerable insights into the surface energies of hexagonal close-packed metals. (paper)

  8. Theory of stable allocations

    Directory of Open Access Journals (Sweden)

    Pantelić Svetlana

    2014-01-01

    Full Text Available The Swedish Royal Academy awarded the 2012 Nobel Prize in Economics to Lloyd Shapley and Alvin Roth, for the theory of stable allocations and the practice of market design. These two American researchers worked independently from each other, combining basic theory and empirical investigations. Through their experiments and practical design they generated a flourishing field of research and improved the performance of many markets. Born in 1923 in Cambridge, Massachusetts, Shapley defended his doctoral thesis at Princeton University in 1953. For many years he worked at RAND, and for more than thirty years he was a professor at UCLA University. He published numerous scientific papers, either by himself or in cooperation with other economists.

  9. Bi-stable optical actuator

    Science.gov (United States)

    Holdener, Fred R.; Boyd, Robert D.

    2000-01-01

    The present invention is a bi-stable optical actuator device that is depowered in both stable positions. A bearing is used to transfer motion and smoothly transition from one state to another. The optical actuator device may be maintained in a stable position either by gravity or a restraining device.

  10. Stability of Picard Bundle Over Moduli Space of Stable Vector ...

    Indian Academy of Sciences (India)

    Abstract. Answering a question of [BV] it is proved that the Picard bundle on the moduli space of stable vector bundles of rank two, on a Riemann surface of genus at least three, with fixed determinant of odd degree is stable.

  11. Air-stable n-type colloidal quantum dot solids

    KAUST Repository

    Ning, Zhijun; Voznyy, Oleksandr; Pan, Jun; Hoogland, Sjoerd H.; Adinolfi, Valerio; Xu, Jixian; Li, Min; Kirmani, Ahmad R.; Sun, Jonpaul; Minor, James C.; Kemp, Kyle W.; Dong, Haopeng; Rollny, Lisa R.; Labelle, André J.; Carey, Graham H.; Sutherland, Brandon R.; Hill, Ian G.; Amassian, Aram; Liu, Huan; Tang, Jiang; Bakr, Osman; Sargent, E. H.

    2014-01-01

    Colloidal quantum dots (CQDs) offer promise in flexible electronics, light sensing and energy conversion. These applications rely on rectifying junctions that require the creation of high-quality CQD solids that are controllably n-type (electron-rich) or p-type (hole-rich). Unfortunately, n-type semiconductors made using soft matter are notoriously prone to oxidation within minutes of air exposure. Here we report high-performance, air-stable n-type CQD solids. Using density functional theory we identify inorganic passivants that bind strongly to the CQD surface and repel oxidative attack. A materials processing strategy that wards off strong protic attack by polar solvents enabled the synthesis of an air-stable n-type PbS CQD solid. This material was used to build an air-processed inverted quantum junction device, which shows the highest current density from any CQD solar cell and a solar power conversion efficiency as high as 8%. We also feature the n-type CQD solid in the rapid, sensitive, and specific detection of atmospheric NO2. This work paves the way for new families of electronic devices that leverage air-stable quantum-tuned materials. © 2014 Macmillan Publishers Limited. All rights reserved.

  12. Air-stable n-type colloidal quantum dot solids

    KAUST Repository

    Ning, Zhijun

    2014-06-08

    Colloidal quantum dots (CQDs) offer promise in flexible electronics, light sensing and energy conversion. These applications rely on rectifying junctions that require the creation of high-quality CQD solids that are controllably n-type (electron-rich) or p-type (hole-rich). Unfortunately, n-type semiconductors made using soft matter are notoriously prone to oxidation within minutes of air exposure. Here we report high-performance, air-stable n-type CQD solids. Using density functional theory we identify inorganic passivants that bind strongly to the CQD surface and repel oxidative attack. A materials processing strategy that wards off strong protic attack by polar solvents enabled the synthesis of an air-stable n-type PbS CQD solid. This material was used to build an air-processed inverted quantum junction device, which shows the highest current density from any CQD solar cell and a solar power conversion efficiency as high as 8%. We also feature the n-type CQD solid in the rapid, sensitive, and specific detection of atmospheric NO2. This work paves the way for new families of electronic devices that leverage air-stable quantum-tuned materials. © 2014 Macmillan Publishers Limited. All rights reserved.

  13. Diamonds from Orapa Mine show a clear subduction signature in SIMS stable isotope data

    Science.gov (United States)

    Chinn, Ingrid L.; Perritt, Samantha H.; Stiefenhofer, Johann; Stern, Richard A.

    2018-05-01

    Spatially resolved analyses reveal considerable isotopic heterogeneity within and among diamonds ranging in size from 0.15 to 4.75 mm from the Orapa Mine, Botswana. The isotopic data are interpreted in conjunction with nitrogen aggregation state data and growth zone relationships from cathodoluminescence images. The integrated information confirms that a distinct diamond growth event (with low IaAB nitrogen aggregation states, moderately high nitrogen contents and δ13C and δ15N values compatible with average mantle values) is younger than the dominant population(s) of Type IaAB diamonds and cores of composite diamonds with more negative and positive δ13C and δ15N values, respectively. A significant proportion of the older diamond generation has high nitrogen contents, well outside the limit sector relationship, and these diamonds are likely to reflect derivation from subducted organic matter. Diamonds with low δ13C values combined with high nitrogen contents and positive δ15N values have not been previously widely recognised, even in studies of diamonds from Orapa. This may have been caused by prior analytical bias towards inclusion-bearing diamonds that are not necessarily representative of the entire range of diamond populations, and because of average measurements from heterogeneous diamonds measured by bulk combustion methods. Two distinct low nitrogen/Type II microdiamond populations were recognised that do not appear to continue into the macrodiamond sizes in the samples studied. Other populations, e.g. those containing residual singly-substituted nitrogen defects, range in size from small microdiamonds to large macrodiamonds. The total diamond content of the Orapa kimberlite thus reflects a complex assortment of multiple diamond populations.

  14. Fractional surface termination of diamond by electrochemical oxidation.

    Science.gov (United States)

    Hoffmann, René; Obloh, Harald; Tokuda, Norio; Yang, Nianjun; Nebel, Christoph E

    2012-01-10

    The crystalline form of sp(3)-hybridized carbon, diamond, offers various electrolyte-stable surface terminations. The H-termination-selective attachment of nitrophenyl diazonium, imaged by AFM, shows that electrochemical oxidation can control the fractional hydrogen/oxygen surface termination of diamond on the nanometer scale. This is of particular interest for all applications relying on interfacial electrochemistry, especially for biointerfaces.

  15. Stability properties of nonlinear dynamical systems and evolutionary stable states

    Energy Technology Data Exchange (ETDEWEB)

    Gleria, Iram, E-mail: iram@fis.ufal.br [Instituto de Física, Universidade Federal de Alagoas, 57072-970 Maceió-AL (Brazil); Brenig, Leon [Faculté des Sciences, Université Libre de Bruxelles, 1050 Brussels (Belgium); Rocha Filho, Tarcísio M.; Figueiredo, Annibal [Instituto de Física and International Center for Condensed Matter Physics, Universidade de Brasília, 70919-970 Brasília-DF (Brazil)

    2017-03-18

    Highlights: • We address the problem of equilibrium stability in a general class of non-linear systems. • We link Evolutionary Stable States (ESS) to stable fixed points of square quasi-polynomial (QP) systems. • We show that an interior ES point may be related to stable interior fixed points of QP systems. - Abstract: In this paper we address the problem of stability in a general class of non-linear systems. We establish a link between the concepts of asymptotic stable interior fixed points of square Quasi-Polynomial systems and evolutionary stable states, a property of some payoff matrices arising from evolutionary games.

  16. Effects of Mars Regolith Analogs, UVC radiation, Temperature, Pressure, and pH on the Growth and Survivability of Methanogenic Archaea and Stable Carbon Isotope Fractionation: Implications for Surface and Subsurface Life on Mars

    Science.gov (United States)

    Sinha, Navita

    Mars is one of the suitable bodies in our solar system that can accommodate extraterrestrial life. The detection of plumes of methane in the Martian atmosphere, geochemical evidence, indication of flow of intermittent liquid water on the Martian surface, and geomorphologies of Mars have bolstered the plausibility of finding extant or evidence of extinct life on its surface and/or subsurface. However, contemporary Mars has been considered as an inhospitable planet for several reasons, such as low atmospheric surface pressure, low surface temperature, and intense DNA damaging radiation. Despite the hostile conditions of Mars, a few strains of methanogenic archaea have shown survivability in limited surface and subsurface conditions of Mars. Methanogens, which are chemolithoautotrophic non-photosynthetic anaerobic archaea, have been considered ideal models for possible Martian life forms for a long time. The search for biosignatures in the Martian atmosphere and possibility of life on the Martian surface under UVC radiation and deep subsurface under high pressure, temperature, and various pHs are the motivations of this research. Analogous to Earth, Martian atmospheric methane could be biological in origin. Chapter 1 provides relevant information about Mars' habitability, methane on Mars, and different strains of methanogens used in this study. Chapter 2 describes the interpretation of the carbon isotopic data of biogenic methane produced by methanogens grown on various Mars analogs and the results provide clues to determine ambiguous sources of methane on Mars. Chapter 3 illustrates the sensitivity of hydrated and desiccated cultures of halophilic and non-halophilic methanogens to DNA-damaging ultraviolet radiations, and the results imply that UVC radiation may not be an enormous constraint for methanogenic life forms on the surface of Mars. Chapters 4, 5, and 6 discuss the data for the survivability, growth, and morphology of methanogens in presumed deep subsurface

  17. One-dimensional stable distributions

    CERN Document Server

    Zolotarev, V M

    1986-01-01

    This is the first book specifically devoted to a systematic exposition of the essential facts known about the properties of stable distributions. In addition to its main focus on the analytic properties of stable laws, the book also includes examples of the occurrence of stable distributions in applied problems and a chapter on the problem of statistical estimation of the parameters determining stable laws. A valuable feature of the book is the author's use of several formally different ways of expressing characteristic functions corresponding to these laws.

  18. Axisymmetric MHD stable sloshing ion distributions

    International Nuclear Information System (INIS)

    Berk, H.L.; Dominguez, N.; Roslyakov, G.V.

    1986-07-01

    The MHD stability of a sloshing ion distribution is investigated in a symmetric mirror cell. Fokker-Planck calculations show that stable configurations are possible for ion injection energies that are at least 150 times greater than the electron temperture. Special axial magnetic field profiles are suggested to optimize the favorable MHD properties

  19. Wall-crossing between stable and co-stable ADHM data

    Science.gov (United States)

    Ohkawa, Ryo

    2018-06-01

    We prove formula between Nekrasov partition functions defined from stable and co-stable ADHM data for the plane following method by Nakajima and Yoshioka (Kyoto J Math 51(2):263-335, 2011) based on the theory of wall-crossing formula developed by Mochizuki (Donaldson type invariants for algebraic surfaces: transition of moduli stacks, Lecture notes in mathematics, vol 1972, Springer, Berlin, 2009). This formula is similar to conjectures by Ito et al. [J High Energy Phys 2013(5):045, 2013, (4.1), (4.2)] for A1 singularity.

  20. Moving stable solitons in Galileon theory

    International Nuclear Information System (INIS)

    Masoumi, Ali; Xiao Xiao

    2012-01-01

    Despite the no-go theorem Endlich et al. (2011) which rules out static stable solitons in Galileon theory, we propose a family of solitons that evade the theorem by traveling at the speed of light. These domain-wall-like solitons are stable under small fluctuations-analysis of perturbation shows neither ghost-like nor tachyon-like instabilities, and perturbative collision of these solitons suggests that they pass through each other asymptotically, which maybe an indication of the integrability of the theory itself.

  1. Influence of horse stable environment on human airways.

    Science.gov (United States)

    Elfman, Lena; Riihimäki, Miia; Pringle, John; Wålinder, Robert

    2009-05-25

    Many people spend considerable amount of time each day in equine stable environments either as employees in the care and training of horses or in leisure activity. However, there are few studies available on how the stable environment affects human airways. This study examined in one horse stable qualitative differences in indoor air during winter and late summer conditions and assessed whether air quality was associated with clinically detectable respiratory signs or alterations to selected biomarkers of inflammation and lung function in stable personnel. The horse stable environment and stable-workers (n = 13) in one stable were investigated three times; first in the winter, second in the interjacent late summer and the third time in the following winter stabling period. The stable measurements included levels of ammonia, hydrogen sulphide, total and respirable dust, airborne horse allergen, microorganisms, endotoxin and glucan. The stable-workers completed a questionnaire on respiratory symptoms, underwent nasal lavage with subsequent analysis of inflammation markers, and performed repeated measurements of pulmonary function. Measurements in the horse stable showed low organic dust levels and high horse allergen levels. Increased viable level of fungi in the air indicated a growing source in the stable. Air particle load as well as 1,3-beta-glucan was higher at the two winter time-points, whereas endotoxin levels were higher at the summer time-point. Two stable-workers showed signs of bronchial obstruction with increased PEF-variability, increased inflammation biomarkers relating to reported allergy, cold or smoking and reported partly work-related symptoms. Furthermore, two other stable-workers reported work-related airway symptoms, of which one had doctor's diagnosed asthma which was well treated. Biomarkers involved in the development of airway diseases have been studied in relation to environmental exposure levels in equine stables. Respirable dust and 1

  2. Influence of horse stable environment on human airways

    Directory of Open Access Journals (Sweden)

    Pringle John

    2009-05-01

    Full Text Available Abstract Background Many people spend considerable amount of time each day in equine stable environments either as employees in the care and training of horses or in leisure activity. However, there are few studies available on how the stable environment affects human airways. This study examined in one horse stable qualitative differences in indoor air during winter and late summer conditions and assessed whether air quality was associated with clinically detectable respiratory signs or alterations to selected biomarkers of inflammation and lung function in stable personnel. Methods The horse stable environment and stable-workers (n = 13 in one stable were investigated three times; first in the winter, second in the interjacent late summer and the third time in the following winter stabling period. The stable measurements included levels of ammonia, hydrogen sulphide, total and respirable dust, airborne horse allergen, microorganisms, endotoxin and glucan. The stable-workers completed a questionnaire on respiratory symptoms, underwent nasal lavage with subsequent analysis of inflammation markers, and performed repeated measurements of pulmonary function. Results Measurements in the horse stable showed low organic dust levels and high horse allergen levels. Increased viable level of fungi in the air indicated a growing source in the stable. Air particle load as well as 1,3-β-glucan was higher at the two winter time-points, whereas endotoxin levels were higher at the summer time-point. Two stable-workers showed signs of bronchial obstruction with increased PEF-variability, increased inflammation biomarkers relating to reported allergy, cold or smoking and reported partly work-related symptoms. Furthermore, two other stable-workers reported work-related airway symptoms, of which one had doctor's diagnosed asthma which was well treated. Conclusion Biomarkers involved in the development of airway diseases have been studied in relation to

  3. On some topological properties of stable measures

    DEFF Research Database (Denmark)

    Nielsen, Carsten Krabbe

    1996-01-01

    Summary The paper shows that the set of stable probability measures and the set of Rational Beliefs relative to a given stationary measure are closed in the strong topology, but not closed in the topology of weak convergence. However, subsets of the set of stable probability measures which...... are characterized by uniformity of convergence of the empirical distribution are closed in the topology of weak convergence. It is demonstrated that such subsets exist. In particular, there is an increasing sequence of sets of SIDS measures who's union is the set of all SIDS measures generated by a particular...... system and such that each subset consists of stable measures. The uniformity requirement has a natural interpretation in terms of plausibility of Rational Beliefs...

  4. Stable isotope research pool inventory

    International Nuclear Information System (INIS)

    1980-12-01

    This report contains a listing of electromagnetically separated stable isotopes which are available for distribution within the United States for non-destructive research use from the Oak Ridge National Laboratory on a loan basis. This inventory includes all samples of stable isotopes in the Materials Research Collection and does not designate whether a sample is out on loan or in reprocessing

  5. Stable electroluminescence from passivated nano-crystalline porous silicon using undecylenic acid

    Science.gov (United States)

    Gelloz, B.; Sano, H.; Boukherroub, R.; Wayner, D. D. M.; Lockwood, D. J.; Koshida, N.

    2005-06-01

    Stabilization of electroluminescence from nanocrystalline porous silicon diodes has been achieved by replacing silicon-hydrogen bonds terminating the surface of nanocrystalline silicon with more stable silicon-carbon (Si-C) bonds. Hydrosilylation of the surface of partially and anodically oxidized porous silicon samples was thermally induced at about 90 °C using various different organic molecules. Devices whose surface have been modified with stable covalent bonds shows no degradation in the EL efficiency and EL output intensity under DC operation for several hours. The enhanced stability can be attributed to the high chemical resistance of Si-C bonds against current-induced surface oxidation associated with the generation of nonradiative defects. Although devices treated with 1-decene exhibit reduced EL efficiency and brightness compared to untreatred devices, other molecules, such as ethyl-undecylenate and particularly undecylenic acid provide stable and more efficient visible electroluminescence at room temperature. Undecylenic acid provides EL brightness as high as that of an untreated device.

  6. Stable electroluminescence from passivated nano-crystalline porous silicon using undecylenic acid

    Energy Technology Data Exchange (ETDEWEB)

    Gelloz, B.; Sano, H.; Koshida, N. [Dept. Elec. and Elec. Eng., Tokyo Univ. of A and T, Koganei, Tokyo 184-8588 (Japan); Boukherroub, R. [Laboratoire de Physique de la Matiere Condensee, Ecole Polytechnique, Route de Saclay, 91128 Palaiseau (France); Wayner, D.D.M.; Lockwood, D.J. [National Research Council, Ottawa (Canada)

    2005-06-01

    Stabilization of electroluminescence from nanocrystalline porous silicon diodes has been achieved by replacing silicon-hydrogen bonds terminating the surface of nanocrystalline silicon with more stable silicon-carbon (Si-C) bonds. Hydrosilylation of the surface of partially and anodically oxidized porous silicon samples was thermally induced at about 90 C using various different organic molecules. Devices whose surface have been modified with stable covalent bonds shows no degradation in the EL efficiency and EL output intensity under DC operation for several hours. The enhanced stability can be attributed to the high chemical resistance of Si-C bonds against current-induced surface oxidation associated with the generation of nonradiative defects. Although devices treated with 1-decene exhibit reduced EL efficiency and brightness compared to untreated devices, other molecules, such as ethyl-undecylenate and particularly undecylenic acid provide stable and more efficient visible electroluminescence at room temperature. Undecylenic acid provides EL brightness as high as that of an untreated device. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  7. Dynamically Stable Legged Locomotion

    Science.gov (United States)

    1981-11-30

    the laboratory. Harry Asada, Wayne Book, Nancy Cornelius, Sesh Murthy and Ivan Sutherland read various drafts of this report, for which we are...particularly helpful in providing an atmosphere where things could get started. Craig Fields and Clint Kelly deserve special credit for letting the idea of...legged technology capture their imaginations, even before we could show them tangible results. We are especially indebted to Ivan Sutherland for his

  8. Hydration of excess electrons trapped in charge pockets on molecular surfaces

    Science.gov (United States)

    Jalbout, Abraham F.; Del Castillo, R.; Adamowicz, Ludwik

    2007-01-01

    In this work we strive to design a novel electron trap located on a molecular surface. The process of electron trapping involves hydration of the trapped electron. Previous calculations on surface electron trapping revealed that clusters of OH groups can form stable hydrogen-bonded networks on one side of a hydrocarbon surface (i.e. cyclohexane sheets), while the hydrogen atoms on the opposite side of the surface form pockets of positive charge that can attract extra negative charge. The excess electron density on such surfaces can be further stabilized by interactions with water molecules. Our calculations show that these anionic systems are stable with respect to vertical electron detachment (VDE).

  9. Thermally Stable Nanocrystalline Steel

    Science.gov (United States)

    Hulme-Smith, Christopher Neil; Ooi, Shgh Woei; Bhadeshia, Harshad K. D. H.

    2017-10-01

    Two novel nanocrystalline steels were designed to withstand elevated temperatures without catastrophic microstructural changes. In the most successful alloy, a large quantity of nickel was added to stabilize austenite and allow a reduction in the carbon content. A 50 kg cast of the novel alloy was produced and used to verify the formation of nanocrystalline bainite. Synchrotron X-ray diffractometry using in situ heating showed that austenite was able to survive more than 1 hour at 773 K (500 °C) and subsequent cooling to ambient temperature. This is the first reported nanocrystalline steel with high-temperature capability.

  10. Identifying nitrate sources and transformations in surface water by combining dual isotopes of nitrate and stable isotope mixing model in a watershed with different land uses and multi-tributaries

    Science.gov (United States)

    Wang, Meng; Lu, Baohong

    2017-04-01

    Nitrate is essential for the growth and survival of plants, animals and humans. However, excess nitrate in drinking water is regarded as a health hazard as it is linked to infant methemoglobinemia and esophageal cancer. Revealing nitrate characteristics and identifying its sources are fundamental for making effective water management strategies, but nitrate sources in multi-tributaries and mixed land covered watersheds remain unclear. It is difficult to determine the predominant NO3- sources using conventional water quality monitoring techniques. In our study, based on 20 surface water sampling sites for more than two years' monitoring from April 2012 to December 2014, water chemical and dual isotopic approaches (δ15N-NO3- and δ18O-NO3-) were integrated for the first time to evaluate nitrate characteristics and sources in the Huashan watershed, Jianghuai hilly region, East China. The results demonstrated that nitrate content in surface water was relatively low in the downstream (nitrate was observed at the source of the river in one of the sub-watersheds, which exhibited an exponential decline along the stream due to dilution, absorption by aquatic plants, and high forest cover. Although dramatically decline of nitrate occurred along the stream, denitrification was not found in surface water by analyzing δ15N-NO3- and δ18O-NO3- relationship. Proportional contributions of five potential nitrate sources (i.e., precipitation; manure and sewage; soil nitrogen; nitrate fertilizer; nitrate derived from ammonia fertilizer and rainfall) were estimated using a Bayesian isotope mixing model. Model results indicated nitrate sources varied significantly among different rainfall conditions, land use types, as well as anthropologic activities. In summary, coupling dual isotopes of nitrate (δ15N-NO3- and δ18O-NO3-, simultaneously) with a Bayesian isotope mixing model offers a useful and practical way to qualitatively analyze nitrate sources and transformations as well as

  11. Preparation and characterization of stable aqueous higher-order fullerenes

    International Nuclear Information System (INIS)

    Aich, Nirupam; Flora, Joseph R V; Saleh, Navid B

    2012-01-01

    Stable aqueous suspensions of nC 60 and individual higher fullerenes, i.e. C 70 , C 76 and C 84 , are prepared by a calorimetric modification of a commonly used liquid–liquid extraction technique. The energy requirement for synthesis of higher fullerenes has been guided by molecular-scale interaction energy calculations. Solubilized fullerenes show crystalline behavior by exhibiting lattice fringes in high resolution transmission electron microscopy images. The fullerene colloidal suspensions thus prepared are stable with a narrow distribution of cluster radii (42.7 ± 0.8 nm, 46.0 ± 14.0 nm, 60 ± 3.2 nm and 56.3 ± 1.1 nm for nC 60 , nC 70 , nC 76 and nC 84 , respectively) as measured by time-resolved dynamic light scattering. The ζ-potential values for all fullerene samples showed negative surface potentials with similar magnitude ( − 38.6 ± 5.8 mV, − 39.1 ± 4.2 mV, − 38.9 ± 5.8 mV and − 41.7 ± 5.1 mV for nC 60 , nC 70 , nC 76 and nC 84 , respectively), which provide electrostatic stability to the colloidal clusters. This energy-based modified solubilization technique to produce stable aqueous fullerenes will likely aid in future studies focusing on better applicability, determination of colloidal properties, and understanding of environmental fate, transport and toxicity of higher-order fullerenes. (paper)

  12. Stable configurations of graphene on silicon

    Energy Technology Data Exchange (ETDEWEB)

    Javvaji, Brahmanandam; Shenoy, Bhamy Maithry [Department of Aerospace Engineering, Indian Institute of Science, Bangalore 560012 (India); Mahapatra, D. Roy, E-mail: droymahapatra@aero.iisc.ernet.in [Department of Aerospace Engineering, Indian Institute of Science, Bangalore 560012 (India); Ravikumar, Abhilash [Department of Metallurgical and Materials Engineering, National Institute of Technology Karnataka, Surathkal 575025 (India); Hegde, G.M. [Center for Nano Science and Engineering, Indian Institute of Science, Bangalore 560012 (India); Rizwan, M.R. [Department of Metallurgical and Materials Engineering, National Institute of Technology Karnataka, Surathkal 575025 (India)

    2017-08-31

    Highlights: • Simulations of epitaxial growth process for silicon–graphene system is performed. • Identified the most favourable orientation of graphene sheet on silicon substrate. • Atomic local strain due to the silicon–carbon bond formation is analyzed. - Abstract: Integration of graphene on silicon-based nanostructures is crucial in advancing graphene based nanoelectronic device technologies. The present paper provides a new insight on the combined effect of graphene structure and silicon (001) substrate on their two-dimensional anisotropic interface. Molecular dynamics simulations involving the sub-nanoscale interface reveal a most favourable set of temperature independent orientations of the monolayer graphene sheet with an angle of ∽15° between its armchair direction and [010] axis of the silicon substrate. While computing the favorable stable orientations, both the translation and the rotational vibrations of graphene are included. The possible interactions between the graphene atoms and the silicon atoms are identified from their coordination. Graphene sheet shows maximum bonding density with bond length 0.195 nm and minimum bond energy when interfaced with silicon substrate at 15° orientation. Local deformation analysis reveals probability distribution with maximum strain levels of 0.134, 0.047 and 0.029 for 900 K, 300 K and 100 K, respectively in silicon surface for 15° oriented graphene whereas the maximum probable strain in graphene is about 0.041 irrespective of temperature. Silicon–silicon dimer formation is changed due to silicon–carbon bonding. These results may help further in band structure engineering of silicon–graphene lattice.

  13. Risk Aversion in Game Shows

    DEFF Research Database (Denmark)

    Andersen, Steffen; Harrison, Glenn W.; Lau, Morten I.

    2008-01-01

    We review the use of behavior from television game shows to infer risk attitudes. These shows provide evidence when contestants are making decisions over very large stakes, and in a replicated, structured way. Inferences are generally confounded by the subjective assessment of skill in some games......, and the dynamic nature of the task in most games. We consider the game shows Card Sharks, Jeopardy!, Lingo, and finally Deal Or No Deal. We provide a detailed case study of the analyses of Deal Or No Deal, since it is suitable for inference about risk attitudes and has attracted considerable attention....

  14. Measuring performance at trade shows

    DEFF Research Database (Denmark)

    Hansen, Kåre

    2004-01-01

    Trade shows is an increasingly important marketing activity to many companies, but current measures of trade show performance do not adequately capture dimensions important to exhibitors. Based on the marketing literature's outcome and behavior-based control system taxonomy, a model is built...... that captures a outcome-based sales dimension and four behavior-based dimensions (i.e. information-gathering, relationship building, image building, and motivation activities). A 16-item instrument is developed for assessing exhibitors perceptions of their trade show performance. The paper presents evidence...

  15. Applications of stable isotopes

    International Nuclear Information System (INIS)

    Gregg, C.T.

    1977-01-01

    Clinical applications include the galactose breath test which consists of oral administration of 13 C-labeled galactose and measurement of the 13 C content of respired CO 2 as a function of time in patients with cirrhotic livers for diagnosis of liver dysfunction. Another application was the breath test to study glucose metabolism in children. Respired 13 CO 2 from ingested glucose- 13 C was measured for normal and diabetic children. Studies on mice in which 60 percent of the body carbon was replaced with 13 C failed to show significant effects of the isotope. Studies on biochemical applications include nuclear magnetic resonance studies of 13 C-labeled amino acids from Chlorella pyrenoidosa; studies on 15 N nmr spectra of arginine-guanidino- 13 C-2,3-- 15 N 2 as a function of pH; and isolation of fatty acids from algae

  16. Stable and Enforceable

    DEFF Research Database (Denmark)

    Hallett, Andrew Hughes; Hougaard Jensen, Svend E.

    2011-01-01

    Since the great financial crash, the need for new fiscal rules to prevent unsustainable fiscal policies is universally recognised. In practice such rules, including those in the Stability and Growth Pact, have proved to be impossible to enforce. Thus, to avoid unsustainable fiscal policies...... reappearing, and to prevent monetary policy from being undermined by undisciplined governments, there is a need for a framework capable of imposing fiscal discipline. This paper considers an intertemporal assignment, where fiscal policy focuses on long-term objectives and monetary policy on short...... which the debt targeting regime should operate. Making these factors explicit would both improve the credibility of planned fiscal policies and reduce risk premia on borrowing costs. We finally show how Europe’s competitiveness pact, and debt restructuring operations, can be used to maximise...

  17. Development of Stable Isotope Technology

    International Nuclear Information System (INIS)

    Jeong, Do Young; Kim, Cheol Jung; Han, Jae Min

    2009-03-01

    KAERI has obtained an advanced technology with singular originality for laser stable isotope separation. Objectives for this project are to get production technology of Tl-203 stable isotope used for medical application and are to establish the foundation of the pilot system, while we are taking aim at 'Laser Isotope Separation Technology to make resistance to the nuclear proliferation'. And we will contribute to ensuring a nuclear transparency in the world society by taking part in a practical group of NSG and being collaboration with various international groups related to stable isotope separation technology

  18. Increasing atmospheric CO2 overrides the historical legacy of multiple stable biome states in Africa.

    Science.gov (United States)

    Moncrieff, Glenn R; Scheiter, Simon; Bond, William J; Higgins, Steven I

    2014-02-01

    The dominant vegetation over much of the global land surface is not predetermined by contemporary climate, but also influenced by past environmental conditions. This confounds attempts to predict current and future biome distributions, because even a perfect model would project multiple possible biomes without knowledge of the historical vegetation state. Here we compare the distribution of tree- and grass-dominated biomes across Africa simulated using a dynamic global vegetation model (DGVM). We explicitly evaluate where and under what conditions multiple stable biome states are possible for current and projected future climates. Our simulation results show that multiple stable biomes states are possible for vast areas of tropical and subtropical Africa under current conditions. Widespread loss of the potential for multiple stable biomes states is projected in the 21st Century, driven by increasing atmospheric CO2 . Many sites where currently both tree-dominated and grass-dominated biomes are possible become deterministically tree-dominated. Regions with multiple stable biome states are widespread and require consideration when attempting to predict future vegetation changes. Testing for behaviour characteristic of systems with multiple stable equilibria, such as hysteresis and dependence on historical conditions, and the resulting uncertainty in simulated vegetation, will lead to improved projections of global change impacts. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  19. Force production during squats performed with a rotational resistance device under stable versus unstable conditions.

    Science.gov (United States)

    Moras, Gerard; Vázquez-Guerrero, Jairo

    2015-11-01

    [Purpose] Force production during a squat action on a rotational resistance device (RRD) under stable and unstable conditions. [Subjects and Methods] Twenty-one healthy males were asked to perform six sets of six repetitions of squats on an RRD on either stable or unstable surfaces. The stable and unstable sets were performed on different days. Muscular outputs were obtained from a linear encoder and a strain gauge fixed to a vest. [Results] Overall, the results showed no significant differences for any of the dependent variables across exercise modes. Forcemean outputs were higher in the concentric phase than in the eccentric phase for each condition, but there were no differences in velocity, time or displacement. The forcepeak was similar in the eccentric and concentric phases of movement under both stable and unstable conditions. There were no significant differences in forcemean between sets per condition or between conditions. [Conclusion] These results suggest that performing squats with a RRD achieves similar forcemean and forcepeak under stable and unstable conditions. The forcepeak produced is also similar in concentric and eccentric phases.

  20. Highly air stable passivation of graphene based field effect devices.

    Science.gov (United States)

    Sagade, Abhay A; Neumaier, Daniel; Schall, Daniel; Otto, Martin; Pesquera, Amaia; Centeno, Alba; Elorza, Amaia Zurutuza; Kurz, Heinrich

    2015-02-28

    The sensitivity of graphene based devices to surface adsorbates and charge traps at the graphene/dielectric interface requires proper device passivation in order to operate them reproducibly under ambient conditions. Here we report on the use of atomic layer deposited aluminum oxide as passivation layer on graphene field effect devices (GFETs). We show that successful passivation produce hysteresis free DC characteristics, low doping level GFETs stable over weeks though operated and stored in ambient atmosphere. This is achieved by selecting proper seed layer prior to deposition of encapsulation layer. The passivated devices are also demonstrated to be robust towards the exposure to chemicals and heat treatments, typically used during device fabrication. Additionally, the passivation of high stability and reproducible characteristics is also shown for functional devices like integrated graphene based inverters.

  1. Ultrathin and stable Nickel films as transparent conductive electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Grilli, M.L., E-mail: marialuisa.grilli@enea.it [ENEA, Materials Technology Unit, Via Anguillarese 301, 00123 Rome (Italy); Di Sarcina, I. [ENEA, Materials Technology Unit, Via Anguillarese 301, 00123 Rome (Italy); Bossi, S. [ENEA, Robotics Laboratory, Via Anguillarese 301, 00123 Rome (Italy); The Biorobotics Institute, Scuola Superiore Sant' Anna, Viale Rinaldo Piaggio 34, 56025 Pontedera, Pisa (Italy); Rinaldi, A.; Pilloni, L.; Piegari, A. [ENEA, Materials Technology Unit, Via Anguillarese 301, 00123 Rome (Italy)

    2015-11-02

    Ultrathin stable transparent conductive nickel films were deposited on quartz substrates by radio frequency sputtering at room temperature. Such films showed visible transmittance up to 80% and conductivity up to 1.8 × 10{sup 4} S/cm, further increased to 2,3 × 10{sup 5} S/cm by incorporation of a micrometric silver grid. Atomic force microscopy and scanning electron microscopy revealed quite compact, smooth and low surface roughness films. Excellent film stability, ease, fast and low cost process fabrication make these films highly competitive compared to indium tin oxide alternative transparent conductors. Films were characterized regarding their morphological, optical and electrical properties. - Highlights: • Indium-free transparent conductors are proposed. • Ultrathin Ni films are fabricated with a very fast process at room temperature. • Films have conductivity values up to 1.8 × 10{sup 4} S/cm. • Ni ultrathin films are good candidates for UV and NIR optoelectronic applications.

  2. Tokyo Motor Show 2003; Tokyo Motor Show 2003

    Energy Technology Data Exchange (ETDEWEB)

    Joly, E.

    2004-01-01

    The text which follows present the different techniques exposed during the 37. Tokyo Motor Show. The report points out the great tendencies of developments of the Japanese automobile industry. The hybrid electric-powered vehicles or those equipped with fuel cells have been highlighted by the Japanese manufacturers which allow considerable budgets in the research of less polluting vehicles. The exposed models, although being all different according to the manufacturer, use always a hybrid system: fuel cell/battery. The manufacturers have stressed too on the intelligent systems for navigation and safety as well as on the design and comfort. (O.M.)

  3. Stable isotope research pool inventory

    International Nuclear Information System (INIS)

    1984-03-01

    This report contains a listing of electromagnetically separated stable isotopes which are available at the Oak Ridge National Laboratory for distribution for nondestructive research use on a loan basis. This inventory includes all samples of stable isotopes in the Research Materials Collection and does not designate whether a sample is out on loan or is in reprocessing. For some of the high abundance naturally occurring isotopes, larger amounts can be made available; for example, Ca-40 and Fe-56

  4. French days on stable isotopes

    International Nuclear Information System (INIS)

    2000-01-01

    These first French days on stable isotopes took place in parallel with the 1. French days of environmental chemistry. Both conferences had common plenary sessions. The conference covers all aspects of the use of stable isotopes in the following domains: medicine, biology, environment, tracer techniques, agronomy, food industry, geology, petroleum geochemistry, cosmo-geochemistry, archaeology, bio-geochemistry, hydrology, climatology, nuclear and particle physics, astrophysics, isotope separations etc.. Abstracts available on CD-Rom only. (J.S.)

  5. Stable isotope research pool inventory

    International Nuclear Information System (INIS)

    1982-01-01

    This report contains a listing of electromagnetically separated stable isotopes which are available for distribution within the United States for nondestructive research use from the Oak Ridge National Laboratory on a loan basis. This inventory includes all samples of stable isotopes in the Material Research Collection and does not designate whether a sample is out on loan or in reprocessing. For some of the high abundance naturally occurring isotopes, larger amounts can be made available; for example, Ca-40 and Fe-56

  6. Antiferromagnetic MnN layer on the MnGa(001) surface

    Energy Technology Data Exchange (ETDEWEB)

    Guerrero-Sánchez, J., E-mail: guerrero@cnyn.unam.mx; Takeuchi, Noboru

    2016-12-30

    Highlights: • A ferromagnetic Gallium terminated surface is stable before N incorporation. • After N incorporation, an antiferromagnetic MnN layer becomes stable in a wide range of chemical potential. • Spin density distribution shows an antiferromagnetic/ferromagnetic (MnN/MnGa) arrangement at the surface. - Abstract: Spin polarized first principles total energy calculations have been applied to study the stability and magnetic properties of the MnGa(001) surface and the formation of a topmost MnN layer with the deposit of nitrogen. Before nitrogen adsorption, surface formation energies show a stable gallium terminated ferromagnetic surface. After incorporation of nitrogen atoms, the antiferromagnetic manganese terminated surface becomes stable due to the formation of a MnN layer (Mn-N bonding at the surface). Spin density distribution shows a ferromagnetic/antiferromagnetic arrangement in the first surface layers. This thermodynamically stable structure may be exploited to growth MnGa/MnN magnetic heterostructures as well as to look for exchange biased systems.

  7. Reality show: um paradoxo nietzschiano

    Directory of Open Access Journals (Sweden)

    Ilana Feldman

    2011-01-01

    Full Text Available

    O fenômeno dos reality shows - e a subseqüente relação entre imagem e verdade - assenta-se sobre uma série de paradoxos. Tais paradoxos podem ser compreendidos à luz do pensamento do filósofo alemão Friedrich Nietzsche, que, através dos usos de formulações paradoxais, concebia a realidade como um mundo de pura aparência e a verdade como um acréscimo ficcional, como um efeito. A ficção é então tomada, na filosofia de Nietzsche, não em seu aspecto falsificante e desrealizador - como sempre pleiteou nossa tradição metafísica -, mas como condição necessária para que certa espécie de invenção possa operar como verdade. Sendo assim, a própria expressão reality show, através de sua formulação paradoxal, engendra explicitamente um mundo de pura aparência, em que a verdade, a parte reality da proposição, é da ordem do suplemento, daquilo que se acrescenta ficcionalmente - como um adjetivo - a show. O ornamento, nesse caso, passa a ocupar o lugar central, apontando para o efeito produzido: o efeito-de-verdade. Seguindo, então, o pensamento nietzschiano e sua atualização na contemporaneidade, investigaremos de que forma os televisivos “shows de realidade” operam paradoxalmente, em consonância com nossas paradoxais práticas culturais.

  8. Solutions for the stable roommates problem with payments

    NARCIS (Netherlands)

    Biró, Péter; Bomhoff, M.J.; Golovach, Petr A.; Kern, Walter

    2014-01-01

    The stable roommates problem with payments has as input a graph G = (V , E ) with an edge weighting w : E → R≥0 and the problem is to find a stable solution. By pinpointing a relationship to the accessibility of the coalition structure core of matching games, we give a constructive proof for showing

  9. DFT computations of the lattice constant, stable atomic structure and ...

    African Journals Online (AJOL)

    This paper presents the most stable atomic structure and lattice constant of Fullerenes (C60). FHI-aims DFT code was used to predict the stable structure and the computational lattice constant of C60. These were compared with known experimental structures and lattice constants of C60. The results obtained showed that ...

  10. Isolation of thermally stable cellulose nanocrystals by phosphoric acid hydrolysis.

    Science.gov (United States)

    Camarero Espinosa, Sandra; Kuhnt, Tobias; Foster, E Johan; Weder, Christoph

    2013-04-08

    On account of their intriguing mechanical properties, low cost, and renewable nature, high-aspect-ratio cellulose nanocrystals (CNCs) are an attractive component for many nanomaterials. Due to hydrogen bonding between their surface hydroxyl groups, unmodified CNCs (H-CNCs) aggregate easily and are often difficult to disperse. It is shown here that on account of ionic repulsion between charged surface groups, slightly phosphorylated CNCs (P-CNCs, average dimensions 31 ± 14 × 316 ± 127 nm, surface charge density = 10.8 ± 2.7 mmol/kg cellulose), prepared by controlled hydrolysis of cotton with phosphoric acid, are readily dispersible and form stable dispersions in polar solvents such as water, dimethyl sulfoxide, and dimethylformamide. Thermogravimetric analyses reveal that these P-CNCs exhibit a much higher thermal stability than partially sulfated CNCs (S-CNCs), which are frequently employed, but suffer from limited thermal stability. Nanocomposites of an ethylene oxide-epichlorohydrin copolymer and H-CNCs, S-CNCs, and P-CNCs were prepared, and their mechanical properties were studied by dynamic mechanical thermal analysis. The results show that P-CNCs offer a reinforcing capability that is comparable to that of H-CNCs or S-CNCs.

  11. Optimization of Parameters of Asymptotically Stable Systems

    Directory of Open Access Journals (Sweden)

    Anna Guerman

    2011-01-01

    Full Text Available This work deals with numerical methods of parameter optimization for asymptotically stable systems. We formulate a special mathematical programming problem that allows us to determine optimal parameters of a stabilizer. This problem involves solutions to a differential equation. We show how to chose the mesh in order to obtain discrete problem guaranteeing the necessary accuracy. The developed methodology is illustrated by an example concerning optimization of parameters for a satellite stabilization system.

  12. The Nature of Stable Insomnia Phenotypes

    Science.gov (United States)

    Pillai, Vivek; Roth, Thomas; Drake, Christopher L.

    2015-01-01

    Study Objectives: We examined the 1-y stability of four insomnia symptom profiles: sleep onset insomnia; sleep maintenance insomnia; combined onset and maintenance insomnia; and neither criterion (i.e., insomnia cases that do not meet quantitative thresholds for onset or maintenance problems). Insomnia cases that exhibited the same symptom profile over a 1-y period were considered to be phenotypes, and were compared in terms of clinical and demographic characteristics. Design: Longitudinal. Setting: Urban, community-based. Participants: Nine hundred fifty-four adults with Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition based current insomnia (46.6 ± 12.6 y; 69.4% female). Interventions: None. Measurements and results: At baseline, participants were divided into four symptom profile groups based on quantitative criteria. Follow-up assessment 1 y later revealed that approximately 60% of participants retained the same symptom profile, and were hence judged to be phenotypes. Stability varied significantly by phenotype, such that sleep onset insomnia (SOI) was the least stable (42%), whereas combined insomnia (CI) was the most stable (69%). Baseline symptom groups (cross-sectionally defined) differed significantly across various clinical indices, including daytime impairment, depression, and anxiety. Importantly, however, a comparison of stable phenotypes (longitudinally defined) did not reveal any differences in impairment or comorbid psychopathology. Another interesting finding was that whereas all other insomnia phenotypes showed evidence of an elevated wake drive both at night and during the day, the “neither criterion” phenotype did not; this latter phenotype exhibited significantly higher daytime sleepiness despite subthreshold onset and maintenance difficulties. Conclusions: By adopting a stringent, stability-based definition, this study offers timely and important data on the longitudinal trajectory of specific insomnia phenotypes. With

  13. [Current Treatment of Stable Angina].

    Science.gov (United States)

    Toggweiler, Stefan; Jamshidi, Peiman; Cuculi, Florim

    2015-06-17

    Current therapy for stable angina includes surgical and percutaneous revascularization, which has been improved tremendously over the last decades. Smoking cessation and regular exercise are the cornerstone for prevention of further cerebrovascular events. Medical treatment includes treatment of cardiovascular risk factors and antithrombotic management, which can be a challenge in some patients. Owing to the fact the coronary revascularization is readily accessible these days in many industrialized countries, the importance of antianginal therapy has decreased over the past years. This article presents a contemporary overview of the management of patients with stable angina in the year 2015.

  14. Reactions and reaction intermediates on iron surfaces--1. Methanol, ethanol, and isopropanol on Fe(100). 2. Hydrocarbons and carboxylic acids

    Energy Technology Data Exchange (ETDEWEB)

    Benziger, J.B.; Madix, R.J.

    1980-09-01

    Temperature-programed desorption and ESCA showed that the alcohols formed alkoxy intermediates on Fe(100) surfaces at room temperature, but that the methoxy and ethoxy species were much more stable than the isopropoxy intermediate. The alkoxy species reacted above 400/sup 0/K by decomposing into carbon monoxide and hydrogen, hydrogenation to alcohol, and scission of C-C and C-O bonds with hydrogenation of the hydrocarbon fragments. Ethylene, acetylene, and cis-2-butene formed stable, unidentified surface species. Methyl chloride formed stable surface methyl groups which decomposed into hydrogen and surface carbide at 475/sup 0/K. Formic and acetic acids yielded stable carboxylate intermediates which decomposed above 490/sup 0/K to hydrogen, carbon monoxide, and carbon dioxide. The studies suggested that the alkoxy surface species may be important intermediates in the Fischer-Tropsch reaction on iron.

  15. Remarks on stable and quasi-stable k-strings at large N

    International Nuclear Information System (INIS)

    Armoni, A.; Shifman, M.

    2003-01-01

    We discuss k-strings in the large-N Yang-Mills theory and its supersymmetric extension. Whereas the tension of the bona fide (stable) QCD string is expected to depend only on the N-ality of the representation, tensions that depend on specific representation R are often reported in the lattice literature. In particular, adjoint strings are discussed and found in certain simulations. We clarify this issue by systematically exploiting the notion of the quasi-stable strings which becomes well-defined at large N. The quasi-stable strings with representation-dependent tensions decay, but the decay rate (per unit length per unit time) is suppressed as Λ 2 F(N) where F(N) falls off as a function of N. It can be determined on the case-by-case basis. The quasi-stable strings eventually decay into stable strings whose tension indeed depends only on the N-ality. We also briefly review large-N arguments showing why the Casimir formula for the string tension cannot be correct, and present additional arguments in favor of the sine formula. Finally, we comment on the relevance of our estimates to Euclidean lattice measurements

  16. Fundamentals of the LISA stable flight formation

    International Nuclear Information System (INIS)

    Dhurandhar, S V; Nayak, K Rajesh; Koshti, S; Vinet, J-Y

    2005-01-01

    The joint NASA-ESA mission, LISA, relies crucially on the stability of the three-spacecraft constellation. Each of the spacecraft is in heliocentric orbit forming a stable triangle. In this paper we explicitly show with the help of the Clohessy-Wiltshire equations that any configuration of spacecraft lying in the planes making angles of ±60 0 with the ecliptic and given suitable initial velocities within the plane, can be made stable in the sense that the inter-spacecraft distances remain constant to first order in the dimensions of the configuration compared with the distance to the Sun. Such analysis would be useful in order to carry out theoretical studies on the optical links, simulators, etc

  17. A model for a stable coronal loop

    International Nuclear Information System (INIS)

    Hoven, G.V.; Chiuderi, C.; Giachetti, R.

    1977-01-01

    We present here a new plasma-physics model of a stable active-region arch which corresponds to the structure observed in the EUV. Pressure gradients are seen, so that the equilibrium magnetic field must depart from the force-free form valid in the surrounding corona. We take advantage of the data and of the approximate cylindrical symmetry to develop a modified form of the commonly assumed sheared-spiral structure. The dynamic MHD behavior of this new pressure/field model is then evaluated by the Newcomb criterion, taken from controlled-fusion physics, and the results show short-wavelength stability in a specific parameter range. Thus we demonstrate the possibility, for pressure profiles with widths of the order of the magnetic-field scale, that such arches can persist for reasonable periods. Finally, the spatial proportions and magnetic fields of a characteristic stable coronal loop are described

  18. Possibility of stable quark stars

    International Nuclear Information System (INIS)

    Bowers, R.L.; Gleeson, A.M.; Pedigo, R.D.

    1976-08-01

    A recent zero temperature equation of state which contains quark-partons separated from conventional baryons by a phase transition is used to investigate the stability of quark stars. The sensitivity to the input physics is also considered. The conclusions, which are found to be relatively model independent, indicate that a separately identifiable class of stable objects called quark stars does not exist

  19. Radiation-stable polyolefin compositions

    International Nuclear Information System (INIS)

    Rekers, J.W.

    1986-01-01

    This invention relates to compositions of olefinic polymers suitable for high energy radiation treatment. In particular, the invention relates to olefinic polymer compositions that are stable to sterilizing dosages of high energy radiation such as a gamma radiation. Stabilizers are described that include benzhydrol and benzhydrol derivatives; these stabilizers may be used alone or in combination with secondary antioxidants or synergists

  20. Stable carbon isotope analysis of fluvial sediment fluxes over two contrasting C(4) -C(3) semi-arid vegetation transitions.

    Science.gov (United States)

    Puttock, Alan; Dungait, Jennifer A J; Bol, Roland; Dixon, Elizabeth R; Macleod, Christopher J A; Brazier, Richard E

    2012-10-30

    Globally, many drylands are experiencing the encroachment of woody vegetation into grasslands. These changes in ecosystem structure and processes can result in increased sediment and nutrient fluxes due to fluvial erosion. As these changes are often accompanied by a shift from C(4) to C(3) vegetation with characteristic δ(13) C values, stable isotope analysis provides a promising mechanism for tracing these fluxes. Input vegetation, surface sediment and fluvially eroded sediment samples were collected across two contrasting C(4) -C(3) dryland vegetation transitions in New Mexico, USA. Isotope ratio mass spectrometric analyses were performed using a Carlo Erba NA2000 analyser interfaced to a SerCon 20-22 isotope ratio mass spectrometer to determine bulk δ(13) C values. Stable isotope analyses of contemporary input vegetation and surface sediments over the monitored transitions showed significant differences (p fluvially eroded sediment from each of the sites, with no significant variation between surface sediment and eroded sediment values. The significant differences in bulk δ(13) C values between sites were dependent on vegetation input. Importantly, these values were robustly expressed in fluvially eroded sediments, suggesting that stable isotope analysis is suitable for tracing sediment fluxes. Due to the prevalent nature of these dryland vegetation transitions in the USA and globally, further development of stable isotope ratio mass spectrometry has provided a valuable tool for enhanced understanding of functional changes in these ecosystems. Copyright © 2012 John Wiley & Sons, Ltd.

  1. Hyperspectral surface materials map of quadrangles 2964, 2966, 3064, and 3066, Shah-Esmail (617), Reg-Alaqadari (618), Samandkhan-Karez (713), Laki-Bander (611), Jahangir-Naweran (612), and Sreh-Chena (707) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    Hoefen, Todd M.; King, Trude V.V.; Kokaly, Raymond F.; Livo, Keith E.; Giles, Stuart A.; Johnson, Michaela R.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  2. Unraveling of permafrost hydrological variabilities on Central Qinghai-Tibet Plateau using stable isotopic technique.

    Science.gov (United States)

    Yang, Yuzhong; Wu, Qingbai; Hou, Yandong; Zhang, Zhongqiong; Zhan, Jing; Gao, Siru; Jin, Huijun

    2017-12-15

    Permafrost degradation on the Qinghai-Tibet Plateau (QTP) will substantially alter the surface runoff discharge and generation, which changes the recharge processes and influences the hydrological cycle on the QTP. Hydrological connections between different water bodies and the influence of thawing permafrost (ground ice) are not well understood on the QTP. This study applied water stable isotopic method to investigate the permafrost hydrological variabilities in Beiluhe Basin (BLB) on Central QTP. Isotopic variations of precipitation, river flow, thermokarst lake, and near-surface ground ice were identified to figure out the moisture source of them, and to elaborate the hydrological connections in permafrost region. Results suggested that isotopic seasonalities in precipitation is evident, it is showing more positive values in summer seasons, and negative values in winter seasons. Stable isotopes of river flow are mainly distributed in the range of precipitation which is indicative of important replenishment from precipitation. δ 18 O, δD of thermokarst lakes are more positive than precipitation, indicating of basin-scale evaporation of lake water. Comparison of δ I values in different water bodies shows that hydrology of thermokarst lakes was related to thawing of permafrost (ground ice) and precipitation. Near-surface ground ice in BLB exhibits different isotopic characteristics, and generates a special δD-δ 18 O relationship (freezing line): δD=5.81δ 18 O-23.02, which reflects typical freezing of liquid water. From isotopic analysis, it is inferred that near-surface ground ice was mainly recharged by precipitation and active layer water. Stable isotopic and conceptual model is suggestive of striking hydrological connections between precipitation, river flow, thermokarst lake, and ground ice under degrading permafrost. This research provides fundamental comprehensions into the hydrological processes in permafrost regions on QTP, which should be considered

  3. Analysis of Stable Isotope Contents of Surface and Underground ...

    African Journals Online (AJOL)

    Sam Eshun

    (2H/1H) ratios relative to a standard called Standard Mean Ocean Water (SMOW) ..... Hence, higher forest cover has greater influence on heavy isotope ... Accra Plains is influenced by the Atlantic Ocean where the relative humidity is higher ...

  4. Macromolecular surface design: photopatterning of functional stable nitrile oxides

    Czech Academy of Sciences Publication Activity Database

    Altintas, O.; Glassner, M.; Rodriguez-Emmenegger, Cesar; Welle, A.; Trouillet, V.; Barner-Kowollik, C.

    2015-01-01

    Roč. 54, č. 19 (2015), s. 5777-5783 ISSN 1433-7851 R&D Projects: GA ČR(CZ) GBP205/12/G118 Institutional support: RVO:61389013 Keywords : modular ligation * nitrogen heterocycles * polymerization Subject RIV: BO - Biophysics Impact factor: 11.709, year: 2015

  5. Robust combined position and formation control for marine surface craft

    DEFF Research Database (Denmark)

    Ihle, Ivar-Andre F.; Jouffroy, Jerome; Fossen, Thor I.

    We consider the robustness properties of a formation control system for marine surface vessels. Intervessel constraint functions are stabilized to achieve the desired formation configuration. We show that the formation dynamics is Input-to-State Stable (ISS) to both environmental perturbations th...

  6. Modified calcium oxide as stable solid base catalyst for Aldol ...

    Indian Academy of Sciences (India)

    A highly efficient and stable solid-base catalyst for Aldol condensation was ... was bonded on surface of CaO chemically and almost no Ca(OH)2 formed during the modification process. ... cation, corrosion and waste generation attract great.

  7. The nature of stable insomnia phenotypes.

    Science.gov (United States)

    Pillai, Vivek; Roth, Thomas; Drake, Christopher L

    2015-01-01

    We examined the 1-y stability of four insomnia symptom profiles: sleep onset insomnia; sleep maintenance insomnia; combined onset and maintenance insomnia; and neither criterion (i.e., insomnia cases that do not meet quantitative thresholds for onset or maintenance problems). Insomnia cases that exhibited the same symptom profile over a 1-y period were considered to be phenotypes, and were compared in terms of clinical and demographic characteristics. Longitudinal. Urban, community-based. Nine hundred fifty-four adults with Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition based current insomnia (46.6 ± 12.6 y; 69.4% female). None. At baseline, participants were divided into four symptom profile groups based on quantitative criteria. Follow-up assessment 1 y later revealed that approximately 60% of participants retained the same symptom profile, and were hence judged to be phenotypes. Stability varied significantly by phenotype, such that sleep onset insomnia (SOI) was the least stable (42%), whereas combined insomnia (CI) was the most stable (69%). Baseline symptom groups (cross-sectionally defined) differed significantly across various clinical indices, including daytime impairment, depression, and anxiety. Importantly, however, a comparison of stable phenotypes (longitudinally defined) did not reveal any differences in impairment or comorbid psychopathology. Another interesting finding was that whereas all other insomnia phenotypes showed evidence of an elevated wake drive both at night and during the day, the 'neither criterion' phenotype did not; this latter phenotype exhibited significantly higher daytime sleepiness despite subthreshold onset and maintenance difficulties. By adopting a stringent, stability-based definition, this study offers timely and important data on the longitudinal trajectory of specific insomnia phenotypes. With the exception of daytime sleepiness, few clinical differences are apparent across stable phenotypes.

  8. Toward Practical Secure Stable Matching

    Directory of Open Access Journals (Sweden)

    Riazi M. Sadegh

    2017-01-01

    Full Text Available The Stable Matching (SM algorithm has been deployed in many real-world scenarios including the National Residency Matching Program (NRMP and financial applications such as matching of suppliers and consumers in capital markets. Since these applications typically involve highly sensitive information such as the underlying preference lists, their current implementations rely on trusted third parties. This paper introduces the first provably secure and scalable implementation of SM based on Yao’s garbled circuit protocol and Oblivious RAM (ORAM. Our scheme can securely compute a stable match for 8k pairs four orders of magnitude faster than the previously best known method. We achieve this by introducing a compact and efficient sub-linear size circuit. We even further decrease the computation cost by three orders of magnitude by proposing a novel technique to avoid unnecessary iterations in the SM algorithm. We evaluate our implementation for several problem sizes and plan to publish it as open-source.

  9. Stable isotope research pool inventory

    International Nuclear Information System (INIS)

    1986-08-01

    This report contains a listing of electromagnetically separated stable isotopes which are available at the Oak Ridge National Laboratory for distribution for nondestructive research use on a loan basis. This inventory includes all samples of stable isotopes in the Research Materials Collection and does not designate whether a sample is out on loan or is in reprocessing. For some of the high-abundance, naturally occurring isotopes, larger amounts can be made available; for example, Ca-40 and Fe-56. All requests for the loan of samples should be submitted with a summary of the purpose of the loan to: Iotope Distribution Office, Oak Ridge National Laboratory, P.O. Box X, Oak Ridge, Tennessee 37831. Requests from non-DOE contractors and from foreign institutions require DOE approval

  10. Stable isotopes and the environment

    International Nuclear Information System (INIS)

    Krouse, H.R.

    1990-01-01

    Whereas traditionally, stable isotope research has been directed towards resource exploration and development, it is finding more frequent applications in helping to assess the impacts of resource utilization upon ecosystems. Among the many pursuits, two themes are evident: tracing the transport and conversions of pollutants in the environment and better understanding of the interplay among environmental receptors, e.g. food web studies. Stable isotope data are used primarily to identify the presence of pollutants in the environment and with a few exceptions, the consequence of their presence must be assessed by other techniques. Increasing attention has been given to the isotopic composition of humans with many potential applications in areas such as paleodiets, medicine, and criminology. In this brief overview examples are used from the Pacific Rim to illustrate the above concepts. 26 refs., 1 tab., 3 figs

  11. Towards stable acceleration in LINACS

    CERN Document Server

    Dubrovskiy, A D

    2014-01-01

    Ultra-stable and -reproducible high-energy particle beams with short bunches are needed in novel linear accelerators and, in particular, in the Compact Linear Collider CLIC. A passive beam phase stabilization system based on a bunch compression with a negative transfer matrix element R56 and acceleration at a positive off-crest phase is proposed. The motivation and expected advantages of the proposed scheme are outlined.

  12. Stable Structures for Distributed Applications

    OpenAIRE

    Eugen DUMITRASCU; Ion IVAN

    2008-01-01

    For distributed applications, we define the linear, tree and graph structure types with different variants and modalities to aggregate them. The distributed applications have assigned structures that through their characteristics influence the costs of stages for developing cycle and the costs for exploitation, transferred to each user. We also present the quality characteristics of a structure for a stable application, which is focused on stability characteristic. For that characteristic we ...

  13. Stable isotope measurements of atmospheric CO2

    International Nuclear Information System (INIS)

    White, J.W.C.; Ferretti, D.F.; Vaughn, B.H.; Francey, R.J.; Allison, C.E.

    2002-01-01

    The measurement of stable carbon isotope ratios of atmospheric carbon dioxide, δ 13 CO 2 are useful for partitioning surface-atmospheric fluxes into terrestrial and oceanic components. δC 18 OO also has potential for segregating photosynthetic and respiratory fluxes in terrestrial ecosystems. Here we describe in detail the techniques for making these measurements. The primary challenge for all of the techniques used to measure isotopes of atmospheric CO 2 is to achieve acceptable accuracy and precision and to maintain them over the decades needed to observe carbon cycle variability. The keys to success such an approach are diligent intercalibrations of laboratories from around the world, as well as the use of multiple techniques such as dual inlet and GC-IRMS and the intercomparison of such measurements. We focus here on two laboratories, the Stable Isotope Lab at the Institute for Arctic and Alpine Research (INSTAAR) at the University of Colorado is described and the Commonwealth Scientific and Industrial Research Organisation - Atmospheric Research (CSIRO). Different approaches exist at other laboratories (e.g. programs operated by Scripps Institution of Oceanography (SIO) and The Center for Atmospheric and Oceanic Studies, Toboku University (TU)) however these are not discussed here. Finally, we also discuss the recently developed Gas Chromatography - Isotope Ratio Mass Spectrometry (GC-IRMS) technique which holds significant promise for measuring ultra-small samples of gas with good precision. (author)

  14. Nanoscale analysis of the morphology and surface stability of calcium carbonate polymorphs

    Science.gov (United States)

    Sekkal, W.; Zaoui, A.

    2013-04-01

    Under earth surface conditions, in ocean and natural water, calcium carbonate is ubiquitous, forming anhydrous and hydrous minerals. These hydrous phases are of considerable interest for their role as precursors to stable carbonate minerals. Atomistic simulation techniques have been employed here to perform a comprehensive and quantitative study of the structural and energetic stability of dry and hydrous surfaces of calcium carbonate polymorphs using two recently developed forcefields. Results show that the dry forms are prone to ductility; while hydrous phases are found to be brittle. The (001) surface of monohydrocalcite appears to be the most stable (0.99 J/m2) whereas for the ikaite phase, the (001) surface is the most stable. The corresponding value is 0.2 J/m2, i.e. even lower than the surface energy of the Beautiful computed morphology pictures are obtained with Xiao's model and are very similar to the observed SEM images.

  15. Surfaces of Building Practice

    OpenAIRE

    Surynková, Petra

    2009-01-01

    My diploma thesis Surfaces of Building Practice deals with the basic properties of surfaces, their mathematical description, categorization, and application in technical practice. Each studied surface is defined and its process of construction and parametrical description is listed. The thesis studies selected types of surfaces in details - these surfaces include surfaces of revolution, ruled surfaces, screw surfaces, and translational surfaces. An application of each studied surfaces is show...

  16. Engineering stable topography in dense bio-mimetic 3D collagen scaffolds

    Directory of Open Access Journals (Sweden)

    T Alekseeva

    2012-01-01

    Full Text Available Topographic features are well known to influence cell behaviour and can provide a powerful tool for engineering complex, functional tissues. This study aimed to investigate the mechanisms of formation of a stable micro-topography on plastic compressed (PC collagen gels. The uni-directional fluid flow that accompanies PC of collagen gels creates a fluid leaving surface (FLS and a non-fluid leaving surface (non-FLS. Here we tested the hypothesis that the resulting anisotropy in collagen density and stiffness between FLS and non-FLS would influence the fidelity and stability of micro-grooves patterned on these surfaces. A pattern template of parallel-aligned glass fibres was introduced to the FLS or non-FLS either at the start of the compression or halfway through, when a dense FLS had already formed. Results showed that both early and late patterning of the FLS generated grooves that had depth (25 ±7 µm and 19 ±8 µm, respectively and width (55 ±11 µm and 50 ±12 µm, respectively which matched the glass fibre diameter (50 µm. In contrast, early and late patterning of the non-FLS gave much wider (151 ±50 µm and 89 ±14 µm, respectively and shallower (10 ±2.7 µm and 13 ±3.5 µm, respectively grooves than expected. The depth to width ratio of the grooves generated on the FLS remained unaltered under static culture conditions over 2 weeks, indicating that grooves were stable under long term active cell-mediated matrix remodelling. These results indicate that the FLS, characterised by a higher matrix collagen density and stiffness than the non-FLS, provides the most favourable mechanical surface for precise engineering of a stable micro-topography in 3D collagen hydrogel scaffolds.

  17. Modified stainless steel for high performance and stable anode in microbial fuel cells

    International Nuclear Information System (INIS)

    Peng, Xinwen; Chen, Shuiliang; Liu, Lang; Zheng, Suqi; Li, Ming

    2016-01-01

    Graphical abstract: A high performance and stable anode was prepared for microbial fuel cells by surface modification of stainless steel mesh including steps of acid etching, binder-free carbon black (CB) coating and the low-temperature heat treatment below 400 °C. The modified anode could deliver a stable and high current density of 1.91 mA cm −2 . - Highlights: • A high-performance anode for MFC is prepared by surface modification of SSM. • The modified SSM could generate a high current density of up to 1.91 mA cm −2 . • The formation of Fe 3 O 4 layer enhanced the interaction between the CB and SSM. • The modified SSM was stable under the potential of +0.2 V (vs. Ag/AgCl). • The modified SSM was an ideal anode for upscaling applications of MFCs. - Abstract: The surface modification of the stainless steel mesh (SSM) was conducted by acid etching, binder-free carbon black (CB) coating and the low-temperature heat treatment below 400 °C to improve the microbial bioelectrocatalytic activity for use as high-performance anode in microbial fuel cells. The modified SSM, such as SSM/CB-400, could generate a high current density of up to 1.91 mA cm −2 , which was nearly three orders of magnitude higher than the untreated SSM electrode (0.0025 mA cm −2 ). Moreover, it was stable and recovered the equal current density after removal of the formed biofilms. Surface characterization results demonstrate that the performance improvement was attributed to the CB/Fe 3 O 4 composite layer formed onto the surface of the SSM, which protected the biofilms from being poisoned by the Cr component in the SSM and ensured a rapid electron transfer from biofilms to the SSM surface. The CB/Fe 3 O 4 composite layer showed excellent corrosion-resistant under the oxidizing potential of + 0.2 V (vs. Ag/AgCl). Rising the heating temperature to 500 °C, the SSM-500 and SSM/CB-500 electrodes suffered from corrosion due to the formation of α-Fe 2 O 3 crystals.

  18. Equilibrium contact angle or the most-stable contact angle?

    Science.gov (United States)

    Montes Ruiz-Cabello, F J; Rodríguez-Valverde, M A; Cabrerizo-Vílchez, M A

    2014-04-01

    It is well-established that the equilibrium contact angle in a thermodynamic framework is an "unattainable" contact angle. Instead, the most-stable contact angle obtained from mechanical stimuli of the system is indeed experimentally accessible. Monitoring the susceptibility of a sessile drop to a mechanical stimulus enables to identify the most stable drop configuration within the practical range of contact angle hysteresis. Two different stimuli may be used with sessile drops: mechanical vibration and tilting. The most stable drop against vibration should reveal the changeless contact angle but against the gravity force, it should reveal the highest resistance to slide down. After the corresponding mechanical stimulus, once the excited drop configuration is examined, the focus will be on the contact angle of the initial drop configuration. This methodology needs to map significantly the static drop configurations with different stable contact angles. The most-stable contact angle, together with the advancing and receding contact angles, completes the description of physically realizable configurations of a solid-liquid system. Since the most-stable contact angle is energetically significant, it may be used in the Wenzel, Cassie or Cassie-Baxter equations accordingly or for the surface energy evaluation. © 2013 Elsevier B.V. All rights reserved.

  19. A parallel approach to the stable marriage problem

    DEFF Research Database (Denmark)

    Larsen, Jesper

    1997-01-01

    This paper describes two parallel algorithms for the stable marriage problem implemented on a MIMD parallel computer. The algorithms are tested against sequential algorithms on randomly generated and worst-case instances. The results clearly show that the combination fo a very simple problem...... and a commercial MIMD system results in parallel algorithms which are not competitive with sequential algorithms wrt. practical performance. 1 Introduction In 1962 the Stable Marriage Problem was....

  20. Organic synthesis with stable isotopes

    International Nuclear Information System (INIS)

    Daub, G.H.; Kerr, V.N.; Williams, D.L.; Whaley, T.W.

    1978-01-01

    Some general considerations concerning organic synthesis with stable isotopes are presented. Illustrative examples are described and discussed. The examples include DL-2-amino-3-methyl- 13 C-butanoic-3,4- 13 C 2 acid (DL-valine- 13 C 3 ); methyl oleate-1- 13 C; thymine-2,6- 13 C 2 ; 2-aminoethanesulfonic- 13 C acid (taurine- 13 C); D-glucose-6- 13 C; DL-2-amino-3-methylpentanoic-3,4- 13 C 2 acid (DL-isoleucine- 13 C 2 ); benzidine- 15 N 2 ; and 4-ethylsulfonyl-1-naphthalene-sulfonamide- 15 N

  1. Stable isotopes - separation and application

    International Nuclear Information System (INIS)

    Lockhart, I.M.

    1980-01-01

    In this review, methods used for the separation of stable isotopes ( 12 C, 13 C, 14 N, 15 N, 16 O, 17 O, 18 O, 34 S) will be described. The synthesis of labelled compounds, techniques for detection and assay, and areas of application will also be discussed. Particular attention will be paid to the isotopes of carbon, nitrogen, and oxygen; to date, sulphur isotopes have only assumed a minor role. The field of deuterium chemistry is too extensive for adequate treatment; it will therefore be essentially excluded. (author)

  2. Stable agents for imaging investigations

    International Nuclear Information System (INIS)

    Tofe, A.J.

    1976-01-01

    This invention concerns highly stable compounds useful in preparing technetium 99m based scintiscanning exploration agents. The compounds of this invention include a pertechnetate reducing agent or a solution of oxidized pertechnetate and an efficient proportion, sufficient to stabilize the compounds in the presence of oxygen and of radiolysis products, of ascorbic acid or a pharmaceutically acceptable salt or ester of this acid. The invention also concerns a perfected process for preparing a technetium based exploration agent, consisting in codissolving the ascorbic acid or a pharmaceutically acceptable salt or ester of such an acid and a pertechnetate reducing agent in a solution of oxidized pertechnetate [fr

  3. Blood donor show behaviour after an invitation to donate : The influence of collection site factors

    NARCIS (Netherlands)

    Merz, E.-M.; Zijlstra, B.J.H.; de Kort, W.L.A.M.

    2017-01-01

    Background and Objectives Show behaviour after invitation to donate varies considerably across donors. More insight into this variation is important for blood banks in achieving stable stocks. This study examined individual factors determining intended show behaviour. Most importantly, however, this

  4. Blood donor show behavior after an invitation to donate: The influence of collection site factors

    NARCIS (Netherlands)

    Merz, E.M.; Zijlstra, Bonne; De Kort, Wim L.A.M.

    2017-01-01

    Background and Objectives Show behaviour after invitation to donate varies considerably across donors. More insight into this variation is important for blood banks in achieving stable stocks. This study examined individual factors determining intended show behaviour. Most importantly, however, this

  5. Stable cosmology in chameleon bigravity

    Science.gov (United States)

    De Felice, Antonio; Mukohyama, Shinji; Oliosi, Michele; Watanabe, Yota

    2018-02-01

    The recently proposed chameleonic extension of bigravity theory, by including a scalar field dependence in the graviton potential, avoids several fine-tunings found to be necessary in usual massive bigravity. In particular it ensures that the Higuchi bound is satisfied at all scales, that no Vainshtein mechanism is needed to satisfy Solar System experiments, and that the strong coupling scale is always above the scale of cosmological interest all the way up to the early Universe. This paper extends the previous work by presenting a stable example of cosmology in the chameleon bigravity model. We find a set of initial conditions and parameters such that the derived stability conditions on general flat Friedmann background are satisfied at all times. The evolution goes through radiation-dominated, matter-dominated, and de Sitter eras. We argue that the parameter space allowing for such a stable evolution may be large enough to encompass an observationally viable evolution. We also argue that our model satisfies all known constraints due to gravitational wave observations so far and thus can be considered as a unique testing ground of gravitational wave phenomenologies in bimetric theories of gravity.

  6. Stable Heavy Hadrons in ATLAS

    CERN Document Server

    Mackeprang, Rasmus

    2007-01-01

    Several extensions to the SM feature heavy long-lived particles with masses of O(10^2-10^3 GeV) and mean lifetimes fulfilling $CT \\geq 10m$. Among such theories are supersymmetric scenarios as well as extra-dimensional models in which the heavy new particles are seen as Kaluza-Klein excitations of the well-known SM particles. Such particles will, from the point of view of a collider experiment be seen as stable. This thesis is concerned with the case where the exotic heavy particles emph{can} be considered stable while traversing the detector. Specifically the case is considered where the particles in question carry the charge of the strong nuclear force, commonly referred to as emph{colour charge}. A simulation kit has been developed using GEANT4. This framework is the current standard in experimental particle physics for the simulation of interactions of particles with matter, and it is used extensively for detector simulation. The simulation describes the interactions of these particles with matter which i...

  7. On the Restriction of the Location of Stable Points for Generalized Lotka-Volterra

    OpenAIRE

    Livesay, Michael Richard

    2017-01-01

    We develop tools to determine which fixed points in a generalized Lotka-Volterra system are stable, under certain non-degeneracy conditions. We characterize which faces of the boundary of the domain of the Lotka-Volterra system could contain a stable fixed point. Under various relaxed conditions, we show that whenever a face of the boundary contains a stable point there are no other stable points in any strictly larger face of the boundary.

  8. Stable isotope mass spectrometry in petroleum exploration

    International Nuclear Information System (INIS)

    Mathur, Manju

    1997-01-01

    The stable isotope mass spectrometry plays an important role to evaluate the stable isotopic composition of hydrocarbons. The isotopic ratios of certain elements in petroleum samples reflect certain characteristics which are useful for petroleum exploration

  9. Fabrication of surface micro- and nanostructures for superhydrophobic surfaces in electric and electronic applications

    Science.gov (United States)

    Xiu, Yonghao

    our understanding of the roughness effect on superhydrophobicity (both contact angle and hysteresis), structured surfaces from polybutadiene, polyurethane, silica, and Si etc. were successfully prepared. For engineering applications of superhydrophobic surfaces, stability issues regarding UV, mechanical robustness and humid environment need to be investigated. Among these factors, UV stability is the first one to be studied. However, most polymer surfaces we prepared failed the purpose. Silica surfaces with excellent UV stability were prepared. This method consists of preparation of rough silica surfaces, thermal treatment and the following surface hydrophobization by fluoroalkyl silane treatment. Fluoroalkyl groups are UV stable and the underlying species are silica which is also UV stable (UV transparent). UV stability on the surface currently is 5,500 h according the standard test method of ASTM D 4329. No degradation on surface superhydrophobicity was observed. New methods for preparing superhydrophobic and transparent silica surfaces were investigated using urea-choline chloride eutectic liquid to generate fine roughness and reduce the cost for preparation of surface structures. Another possible application for self-cleaning in photovoltaic panels was investigated on Si surfaces by construction of the two-scale rough structures followed by fluoroalkyl silane treatment. Metal (Au) assisted etching was employed to fabricate nanostructures on micrometer pyramid surfaces. The light reflection on the prepared surfaces was investigated. After surface texturing using KOH etching for micrometer pyramids and the following nanostructure using metal assisted etching, surface light reflection reduced to a minimum value which shows that this surface texturing technique is highly promising for improving the photovoltaic efficiency while imparting photovoltaics the self-cleaning feature. This surface is also expected to be UV stable due to the same fluoroalkyl silane used

  10. Design of partially optically stable reflector systems and prisms

    Science.gov (United States)

    Tsai, Chuang-Yu

    2010-09-01

    The characteristics and design method of the total optically stable (TOS) reflector systems/prisms were introduced in an early paper (Tsai and Lin in Appl. Opt. 47:4158-4163, 2008), where only two types of TOS reflector system exist, namely preservation or retroreflection. In this paper, we introduce the partially optically stable (POS) reflector system, which is only optically stable about a specific directional vector; nevertheless, the exiting light ray is not restricted to preservation or retroreflection. The proposed paper also presents an analytic method for the design of POS reflector systems comprised of multiple reflectors. Furthermore, it is shown that a POS prism can be obtained by adding two refracting flat boundary surfaces with specific conditions at the entrance and exit positions of the light ray in an optical system with multiple reflectors.

  11. Tempered stable laws as random walk limits

    OpenAIRE

    Chakrabarty, Arijit; Meerschaert, Mark M.

    2010-01-01

    Stable laws can be tempered by modifying the L\\'evy measure to cool the probability of large jumps. Tempered stable laws retain their signature power law behavior at infinity, and infinite divisibility. This paper develops random walk models that converge to a tempered stable law under a triangular array scheme. Since tempered stable laws and processes are useful in statistical physics, these random walk models can provide a basic physical model for the underlying physical phenomena.

  12. Stable States of Biological Organisms

    Science.gov (United States)

    Yukalov, V. I.; Sornette, D.; Yukalova, E. P.; Henry, J.-Y.; Cobb, J. P.

    2009-04-01

    A novel model of biological organisms is advanced, treating an organism as a self-consistent system subject to a pathogen flux. The principal novelty of the model is that it describes not some parts, but a biological organism as a whole. The organism is modeled by a five-dimensional dynamical system. The organism homeostasis is described by the evolution equations for five interacting components: healthy cells, ill cells, innate immune cells, specific immune cells, and pathogens. The stability analysis demonstrates that, in a wide domain of the parameter space, the system exhibits robust structural stability. There always exist four stable stationary solutions characterizing four qualitatively differing states of the organism: alive state, boundary state, critical state, and dead state.

  13. Super-stable Poissonian structures

    International Nuclear Information System (INIS)

    Eliazar, Iddo

    2012-01-01

    In this paper we characterize classes of Poisson processes whose statistical structures are super-stable. We consider a flow generated by a one-dimensional ordinary differential equation, and an ensemble of particles ‘surfing’ the flow. The particles start from random initial positions, and are propagated along the flow by stochastic ‘wave processes’ with general statistics and general cross correlations. Setting the initial positions to be Poisson processes, we characterize the classes of Poisson processes that render the particles’ positions—at all times, and invariantly with respect to the wave processes—statistically identical to their initial positions. These Poisson processes are termed ‘super-stable’ and facilitate the generalization of the notion of stationary distributions far beyond the realm of Markov dynamics. (paper)

  14. Super-stable Poissonian structures

    Science.gov (United States)

    Eliazar, Iddo

    2012-10-01

    In this paper we characterize classes of Poisson processes whose statistical structures are super-stable. We consider a flow generated by a one-dimensional ordinary differential equation, and an ensemble of particles ‘surfing’ the flow. The particles start from random initial positions, and are propagated along the flow by stochastic ‘wave processes’ with general statistics and general cross correlations. Setting the initial positions to be Poisson processes, we characterize the classes of Poisson processes that render the particles’ positions—at all times, and invariantly with respect to the wave processes—statistically identical to their initial positions. These Poisson processes are termed ‘super-stable’ and facilitate the generalization of the notion of stationary distributions far beyond the realm of Markov dynamics.

  15. Periodicity of the stable isotopes

    CERN Document Server

    Boeyens, J C A

    2003-01-01

    It is demonstrated that all stable (non-radioactive) isotopes are formally interrelated as the products of systematically adding alpha particles to four elementary units. The region of stability against radioactive decay is shown to obey a general trend based on number theory and contains the periodic law of the elements as a special case. This general law restricts the number of what may be considered as natural elements to 100 and is based on a proton:neutron ratio that matches the golden ratio, characteristic of biological and crystal growth structures. Different forms of the periodic table inferred at other proton:neutron ratios indicate that the electronic configuration of atoms is variable and may be a function of environmental pressure. Cosmic consequences of this postulate are examined. (author)

  16. Stable massive particles at colliders

    Energy Technology Data Exchange (ETDEWEB)

    Fairbairn, M.; /Stockholm U.; Kraan, A.C.; /Pennsylvania U.; Milstead, D.A.; /Stockholm U.; Sjostrand, T.; /Lund U.; Skands, P.; /Fermilab; Sloan, T.; /Lancaster U.

    2006-11-01

    We review the theoretical motivations and experimental status of searches for stable massive particles (SMPs) which could be sufficiently long-lived as to be directly detected at collider experiments. The discovery of such particles would address a number of important questions in modern physics including the origin and composition of dark matter in the universe and the unification of the fundamental forces. This review describes the techniques used in SMP-searches at collider experiments and the limits so far obtained on the production of SMPs which possess various colour, electric and magnetic charge quantum numbers. We also describe theoretical scenarios which predict SMPs, the phenomenology needed to model their production at colliders and interactions with matter. In addition, the interplay between collider searches and open questions in cosmology such as dark matter composition are addressed.

  17. Effectiveness and risks of stable iodine prophylaxis

    International Nuclear Information System (INIS)

    Waight, P.J.

    1995-01-01

    The factors upon which the efficacy of stable iodine prophylaxis depends are reviewed, with particular reference to the dose of stable iodine, the timing of the dose, the influence of dietary iodine and the impact of the other prospective actions. The risks of stable iodine ingestion are estimated, and their application to the principle of Justification in outlined. (Author)

  18. Temperature and Humidity Control in Livestock Stables

    DEFF Research Database (Denmark)

    Hansen, Michael; Andersen, Palle; Nielsen, Kirsten M.

    2010-01-01

    The paper describes temperature and humidity control of a livestock stable. It is important to have a correct air flow pattern in the livestock stable in order to achieve proper temperature and humidity control as well as to avoid draught. In the investigated livestock stable the air flow...

  19. Surface-atmosphere decoupling limits accumulation at Summit, Greenland.

    Science.gov (United States)

    Berkelhammer, Max; Noone, David C; Steen-Larsen, Hans Christian; Bailey, Adriana; Cox, Christopher J; O'Neill, Michael S; Schneider, David; Steffen, Konrad; White, James W C

    2016-04-01

    Despite rapid melting in the coastal regions of the Greenland Ice Sheet, a significant area (~40%) of the ice sheet rarely experiences surface melting. In these regions, the controls on annual accumulation are poorly constrained owing to surface conditions (for example, surface clouds, blowing snow, and surface inversions), which render moisture flux estimates from myriad approaches (that is, eddy covariance, remote sensing, and direct observations) highly uncertain. Accumulation is partially determined by the temperature dependence of saturation vapor pressure, which influences the maximum humidity of air parcels reaching the ice sheet interior. However, independent proxies for surface temperature and accumulation from ice cores show that the response of accumulation to temperature is variable and not generally consistent with a purely thermodynamic control. Using three years of stable water vapor isotope profiles from a high altitude site on the Greenland Ice Sheet, we show that as the boundary layer becomes increasingly stable, a decoupling between the ice sheet and atmosphere occurs. The limited interaction between the ice sheet surface and free tropospheric air reduces the capacity for surface condensation to achieve the rate set by the humidity of the air parcels reaching interior Greenland. The isolation of the surface also acts to recycle sublimated moisture by recondensing it onto fog particles, which returns the moisture back to the surface through gravitational settling. The observations highlight a unique mechanism by which ice sheet mass is conserved, which has implications for understanding both past and future changes in accumulation rate and the isotopic signal in ice cores from Greenland.

  20. Highly stable noble-metal nanoparticles in tetraalkylphosphonium ionic liquids for in situ catalysis.

    Science.gov (United States)

    Banerjee, Abhinandan; Theron, Robin; Scott, Robert W J

    2012-01-09

    Gold and palladium nanoparticles were prepared by lithium borohydride reduction of the metal salt precursors in tetraalkylphosphonium halide ionic liquids in the absence of any organic solvents or external nanoparticle stabilizers. These colloidal suspensions remained stable and showed no nanoparticle agglomeration over many months. A combination of electrostatic interactions between the coordinatively unsaturated metal nanoparticle surface and the ionic-liquid anions, bolstered by steric protection offered by the bulky alkylated phosphonium cations, is likely to be the reason behind such stabilization. The halide anion strongly absorbs to the nanoparticle surface, leading to exceptional nanoparticle stability in halide ionic liquids; other tetraalkylphosphonium ionic liquids with non-coordinating anions, such as tosylate and hexafluorophosphate, show considerably lower affinities towards the stabilization of nanoparticles. Palladium nanoparticles stabilized in the tetraalkylphosphonium halide ionic liquid were stable, efficient, and recyclable catalysts for a variety of hydrogenation reactions at ambient pressures with sustained activity. Aerial oxidation of the metal nanoparticles occurred over time and was readily reversed by re-reduction of oxidized metal salts. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Polyelectrolyte brushes: a novel stable lubrication system in aqueous conditions.

    Science.gov (United States)

    Kobayashi, Motoyasu; Terada, Masami; Takahara, Atsushi

    2012-01-01

    Surface-initiated controlled radical copolymerizations of 2-dimethylaminoethyl methacrylate (DMAEMA), 2-(methacryloyloxy)ethyl phosphorylcholine (MPC), 2-(methacryloyloxy)ethyltrimethylammonium chloride) (MTAC), and 3-sulfopropyl methacrylate potassium salt (SPMK) were carried out on a silicon wafer and glass ball to prepare polyelectrolyte brushes with excellent water wettability. The frictional coefficient of the polymer brushes was recorded on a ball-on-plate type tribometer by linear reciprocating motion of the brush specimen at a selected velocity of 1.5 x 10(-3) m s-1 under a normal load of 0.49 N applied to the stationary glass ball (d = 10 mm) at 298 K. The poly(DMAEMA-co-MPC) brush partially cross-linked by bis(2-iodoethoxy)ethane maintained a relatively low friction coefficient around 0.13 under humid air (RH > 75%) even after 200 friction cycles. The poly(SPMK) brush revealed an extremely low friction coefficient around 0.01 even after 450 friction cycles. We supposed that the abrasion of the brush was prevented owing to the good affinity of the poly(SPMK) brush for water forming a water lubrication layer, and electrostatic repulsive interactions among the brushes bearing sulfonic acid groups. Furthermore, the poly(SPMK-co-MTAC) brush with a chemically cross-linked structure showed a stable low friction coefficient in water even after 1400 friction cycles under a normal load of 139 MPa, indicating that the cross-linking structure improved the wear resistance of the brush layer.

  2. Continuous control of asymmetric forebody vortices in a bi-stable state

    Science.gov (United States)

    Wang, Qi-te; Cheng, Ke-ming; Gu, Yun-song; Li, Zhuo-qi

    2018-02-01

    Aiming at the problem of continuous control of asymmetric forebody vortices at a high angle of attack in a bi-stable regime, a dual synthetic jet actuator embedded in an ogive forebody was designed. Alternating unsteady disturbance with varying degree asymmetrical flow fields near the nozzles is generated by adjusting the duty cycle of the drive signal of the actuator, specifically embodying the asymmetric time-averaged pattern of jet velocity, vorticity, and turbulent kinetic energy. Experimental results show that within the range of relatively high angles of attack, including the angle-of-attack region in a bi-stable state, the lateral force of the ogive forebody is continuously controlled by adjusting the duty cycle of the drive signal; the position of the forebody vortices in space, the vorticity magnitude, the total pressure coefficient near the vortex core, and the vortex breakdown location are continuously changed with the duty cycle increased observed from the time-averaged flow field. Instantaneous flow field results indicate that although the forebody vortices are in an unsteady oscillation state, a continuous change in the forebody vortices' oscillation balance position as the duty cycle increases leads to a continuous change in the model's surface pressure distribution and time-averaged lateral force. Different from the traditional control principle, in this study, other different degree asymmetrical states of the forebody vortices except the bi-stable state are obtained using the dual synthetic jet control technology.

  3. Stable Myoelectric Control of a Hand Prosthesis using Non-Linear Incremental Learning

    Directory of Open Access Journals (Sweden)

    Arjan eGijsberts

    2014-02-01

    Full Text Available Stable myoelectric control of hand prostheses remains an open problem. The only successful human-machine interface is surface electromyography, typically allowing control of a few degrees of freedom. Machine learning techniques may have the potential to remove these limitations, but their performance is thus far inadequate: myoelectric signals change over time under the influence of various factors, deteriorating control performance. It is therefore necessary, in the standard approach, to regularly retrain a new model from scratch.We hereby propose a non-linear incremental learning method in which occasional updates with a modest amount of novel training data allow continual adaptation to the changes in the signals. In particular, Incremental Ridge Regression and an approximation of the Gaussian Kernel known as Random Fourier Features are combined to predict finger forces from myoelectric signals, both finger-by-finger and grouped in grasping patterns.We show that the approach is effective and practically applicable to this problem by first analyzing its performance while predicting single-finger forces. Surface electromyography and finger forces were collected from 10 intact subjects during four sessions spread over two different days; the results of the analysis show that small incremental updates are indeed effective to maintain a stable level of performance.Subsequently, we employed the same method on-line to teleoperate a humanoid robotic arm equipped with a state-of-the-art commercial prosthetic hand. The subject could reliably grasp, carry and release everyday-life objects, enforcing stable grasping irrespective of the signal changes, hand/arm movements and wrist pronation and supination.

  4. High stable suspension of magnetite nanoparticles in ethanol by using sono-synthesized nanomagnetite in polyol medium

    International Nuclear Information System (INIS)

    Bastami, Tahereh Rohani; Entezari, Mohammad H.

    2013-01-01

    Graphical abstract: - Highlights: • The sonochemical synthesis of magnetite nanoparticles was carried out in EG without any surfactant. • The nanoparticles with sizes ∼24 nm were composed of small building blocks with sizes ∼2 nm. • The hydrophilic magnetite nanoparticles were stable in ethanol even after 8 months. • Ultrasonic intensity showed a crucial role on the obtained high stable magnetite nanoparticles in ethanol. - Abstract: The sonochemical synthesis of magnetite nanoparticles was carried out at relatively low temperature (80 °C) in ethylene glycol (EG) as a polyol solvent. The particle size was determined by transmission electron microscopy (TEM). The magnetite nanoparticles with an average size of 24 nm were composed of small building blocks with an average size of 2–3 nm and the particles exhibited nearly spherical shape. The surface characterization was investigated by using Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). The stability of magnetite nanoparticles was studied in ethanol as a polar solvent. The nanoparticles showed an enhanced stability in ethanol which is due to the hydrophilic surface of the particles. The colloidal stability of magnetite nanoparticles in ethanol was monitored by UV–visible spectrophotometer. According to the results, the nanoparticles synthesized in 30 min of sonication with intensity of 35 W/cm 2 (50%) led to a maximum stability in ethanol as a polar solvent with respect to the other applied intensities. The obtained magnetite nanoparticles were stable for more than12 months

  5. Stable Oxygen-18 and Deuterium Isotopes

    DEFF Research Database (Denmark)

    Müller, Sascha

    The application of stable Oxygen-18 (18O) and Deuterium (2H) isotopes, as a tracer for fluxes between different compartments of the water cycle was subject of the present PhD-thesis. During a three year period, temporal data from a wide range of water cycle constituents was collected from...... the Skjern River catchment, Denmark. The presented applications focused on studying the isotopic 'input signal' to the hydrosphere in the form of precipitation, the isotopic 'output signal' with its related dynamic processes at a coastal saltwater-freshwater interface (groundwater isotopes) and the temporal...... development within a given lowland headwater catchment (stream water isotopes). Based on our investigations on the precipitation isotopic composition a local meteoric water line (LMWL) was constructed and expressed as: δ2H=7.4 δ18O + 5.36‰. Moreover, we showed that under maritime temperature climate influence...

  6. Moltex Energy's stable salt reactors

    International Nuclear Information System (INIS)

    O'Sullivan, R.; Laurie, J.

    2016-01-01

    A stable salt reactor is a molten salt reactor in which the molten fuel salt is contained in fuel rods. This concept was invented in 1951 and re-discovered and improved recently by Moltex Energy Company. The main advantage of using molten salt fuel is that the 2 problematic fission products cesium and iodine do not exist in gaseous form but rather in a form of a salt that present no danger in case of accident. Another advantage is the strongly negative temperature coefficient for reactivity which means the reactor self-regulates. The feasibility studies have been performed on a molten salt fuel composed of sodium chloride and plutonium/uranium/lanthanide/actinide trichloride. The coolant fluid is a mix of sodium and zirconium fluoride salts that will need low flow rates. The addition of 1 mol% of metal zirconium to the coolant fluid reduces the risk of corrosion with standard steels and the addition of 2% of hafnium reduces the neutron dose. The temperature of the coolant is expected to reach 650 Celsius degrees at the exit of the core. This reactor is designed to be modular and it will be able to burn actinides. (A.C.)

  7. Rare stable isotopes in meteorites

    International Nuclear Information System (INIS)

    Wilson, G.C.

    1981-01-01

    Secondary Ion Mass Spectrometry (SIMS) using accelerators has been applied with success to cosmic ray exposure ages and terrestrial residence times of meteorites by measuring cosmogenic nuclides of Be, Cl, and I. It is proposed to complement this work with experiments on rare stable isotopes, in the hope of setting constraints on the processes of solar nebula/meteoritic formation. The relevant species can be classified as: a) daughter products of extinct nuclides (halflife less than or equal to 2 x 10 8 y) -chronology of the early solar system; b) products of high temperature astrophysical processes - different components incorporated into the solar nebula; and c) products of relatively low temperature processes, stellar winds and cosmic ray reactions - early solar system radiation history. The use of micron-scale primary ion beams will allow detailed sampling of phases within meteorites. Strategies of charge-state selection, molecular disintegration and detection should bring a new set of targets within analytical range. The developing accelerator field is compared to existing (keV energy) ion microprobes

  8. Stable piecewise polynomial vector fields

    Directory of Open Access Journals (Sweden)

    Claudio Pessoa

    2012-09-01

    Full Text Available Let $N={y>0}$ and $S={y<0}$ be the semi-planes of $mathbb{R}^2$ having as common boundary the line $D={y=0}$. Let $X$ and $Y$ be polynomial vector fields defined in $N$ and $S$, respectively, leading to a discontinuous piecewise polynomial vector field $Z=(X,Y$. This work pursues the stability and the transition analysis of solutions of $Z$ between $N$ and $S$, started by Filippov (1988 and Kozlova (1984 and reformulated by Sotomayor-Teixeira (1995 in terms of the regularization method. This method consists in analyzing a one parameter family of continuous vector fields $Z_{epsilon}$, defined by averaging $X$ and $Y$. This family approaches $Z$ when the parameter goes to zero. The results of Sotomayor-Teixeira and Sotomayor-Machado (2002 providing conditions on $(X,Y$ for the regularized vector fields to be structurally stable on planar compact connected regions are extended to discontinuous piecewise polynomial vector fields on $mathbb{R}^2$. Pertinent genericity results for vector fields satisfying the above stability conditions are also extended to the present case. A procedure for the study of discontinuous piecewise vector fields at infinity through a compactification is proposed here.

  9. Stable Structures for Distributed Applications

    Directory of Open Access Journals (Sweden)

    Eugen DUMITRASCU

    2008-01-01

    Full Text Available For distributed applications, we define the linear, tree and graph structure types with different variants and modalities to aggregate them. The distributed applications have assigned structures that through their characteristics influence the costs of stages for developing cycle and the costs for exploitation, transferred to each user. We also present the quality characteristics of a structure for a stable application, which is focused on stability characteristic. For that characteristic we define the estimated measure indicators for a level. The influence of the factors of stability and the ways for increasing it are thus identified, and at the same time the costs of development stages, the costs of usage and the costs of maintenance to be keep on between limits that assure the global efficiency of application. It is presented the base aspects for distributed applications: definition, peculiarities and importance. The aspects for the development cycle of distributed application are detailed. In this article, we alongside give the mechanisms for building the defined structures and analyze the complexity of the defined structures for a distributed application of a virtual store.

  10. Formation of graphene on Ru(0001) surface

    Institute of Scientific and Technical Information of China (English)

    Pan Yi; Shi Dong-Xia; Gao Hong-Jun

    2007-01-01

    We report on the formation of a graphene monolayer on a Ru(0001) surface by annealing the Ru(0001) crystal.The samples are characterized by scanning tunnelling microscopy (STM) and Auger electron spectroscopy (AES). STM images show that the Moiré pattern is caused by the graphene layer mismatched with the underlying Ru(0001) surface and has an N × N superlattice. It is further found that the graphene monolayer on a Ru(0001) surface is very stable at high temperatures. Our results provide a simple and convenient method to produce a graphene monolayer on the Ru(0001) surface, which is used as a template for fabricating functional nanostructures needed in future nano devices and catalysis.

  11. Multipole surface solitons supported by the interface between linear media and nonlocal nonlinear media

    International Nuclear Information System (INIS)

    Shi, Zhiwei; Li, Huagang; Guo, Qi

    2012-01-01

    We address multipole surface solitons occurring at the interface between a linear medium and a nonlocal nonlinear medium. We show the impact of nonlocality, the propagation constant, and the linear index difference of two media on the properties of the surface solitons. We find that there exist a threshold value of the degree of the nonlocality at the same linear index difference of two media, only when the degree of the nonlocality goes beyond the value, the multipole surface solitons can be stable. -- Highlights: ► We show the impact of nonlocality and the linear index difference of two media on the properties of the surface solitons. ► For the surface solitons, only when the degree of the nonlocality goes beyond a threshold value, they can be stable. ► The number of poles and the index difference of two media can all influence the threshold value.

  12. Study of the influence of stable cadmium on the transfer of zinc-65 in an ecosystem irrigated by submersion (irrigated rice field)

    International Nuclear Information System (INIS)

    Myttenaere, C.; Merlini, M.; Dabin, P.; Mousny, J.M.; Pozzi, G.; Bittel, R.

    1975-01-01

    Irrigation water contains varying amounts of stable cadmium from industrial disposal. The presence of this element is capable of modifying the transfer of and affecting the mechanisms of absorption of zinc-65, a radionuclide which is discharged into water by nuclear power stations. This type of interaction between a nuclear contaminant and a conventional contaminant was studied in a rice-field irrigated by submersion. This ecosystem was reproduced under controlled 'mini-rice-field' conditions: the water was enriched in stable zinc (1 ppm) and in stable cadmium (2,5x10 -3 ; 50x10 -3 ppm) so as to reproduce the actual conditions; the stable zinc was traced by means of zinc-65. Fish (20 Carassius auratus L.) were introduced into each compartment of the ecosystem. Samples of irrigation water and surface water were taken during cultivation, and at the end of cultivation the content of stable zinc, radioactive zinc and stable cadmium was determined in each component of the ecosystem. The results show the important influence of a conventional contaminant on the transfer of a radionuclide and justify the use of the term 'associate contaminant' to describe it. (author)

  13. Stable boron nitride diamondoids as nanoscale materials

    International Nuclear Information System (INIS)

    Fyta, Maria

    2014-01-01

    We predict the stability of diamondoids made up of boron and nitrogen instead of carbon atoms. The results are based on quantum-mechanical calculations within density functional theory (DFT) and show some very distinct features compared to the regular carbon-based diamondoids. These features are evaluated with respect to the energetics and electronic properties of the boron nitride diamondoids as compared to the respective properties of the carbon-based diamondoids. We find that BN-diamondoids are overall more stable than their respective C-diamondoid counterparts. The electronic band-gaps (E g ) of the former are overall lower than those for the latter nanostructures but do not show a very distinct trend with their size. Contrary to the lower C-diamondoids, the BN-diamondoids are semiconducting and show a depletion of charge on the nitrogen site. Their differences in the distribution of the molecular orbitals, compared to their carbon-based counterparts, offer additional bonding and functionalization possibilities. These tiny BN-based nanostructures could potentially be used as nanobuilding blocks complementing or substituting the C-diamondoids, based on the desired properties. An experimental realization of boron nitride diamondoids remains to show their feasibility. (paper)

  14. Advanced thermally stable jet fuels

    Energy Technology Data Exchange (ETDEWEB)

    Schobert, H.H.

    1999-01-31

    The Pennsylvania State University program in advanced thermally stable coal-based jet fuels has five broad objectives: (1) Development of mechanisms of degradation and solids formation; (2) Quantitative measurement of growth of sub-micrometer and micrometer-sized particles suspended in fuels during thermal stressing; (3) Characterization of carbonaceous deposits by various instrumental and microscopic methods; (4) Elucidation of the role of additives in retarding the formation of carbonaceous solids; (5) Assessment of the potential of production of high yields of cycloalkanes by direct liquefaction of coal. Future high-Mach aircraft will place severe thermal demands on jet fuels, requiring the development of novel, hybrid fuel mixtures capable of withstanding temperatures in the range of 400--500 C. In the new aircraft, jet fuel will serve as both an energy source and a heat sink for cooling the airframe, engine, and system components. The ultimate development of such advanced fuels requires a thorough understanding of the thermal decomposition behavior of jet fuels under supercritical conditions. Considering that jet fuels consist of hundreds of compounds, this task must begin with a study of the thermal degradation behavior of select model compounds under supercritical conditions. The research performed by The Pennsylvania State University was focused on five major tasks that reflect the objectives stated above: Task 1: Investigation of the Quantitative Degradation of Fuels; Task 2: Investigation of Incipient Deposition; Task 3: Characterization of Solid Gums, Sediments, and Carbonaceous Deposits; Task 4: Coal-Based Fuel Stabilization Studies; and Task 5: Exploratory Studies on the Direct Conversion of Coal to High Quality Jet Fuels. The major findings of each of these tasks are presented in this executive summary. A description of the sub-tasks performed under each of these tasks and the findings of those studies are provided in the remainder of this volume

  15. Surface instabilities in shock loaded granular media

    Science.gov (United States)

    Kandan, K.; Khaderi, S. N.; Wadley, H. N. G.; Deshpande, V. S.

    2017-12-01

    The initiation and growth of instabilities in granular materials loaded by air shock waves are investigated via shock-tube experiments and numerical calculations. Three types of granular media, dry sand, water-saturated sand and a granular solid comprising PTFE spheres were experimentally investigated by air shock loading slugs of these materials in a transparent shock tube. Under all shock pressures considered here, the free-standing dry sand slugs remained stable while the shock loaded surface of the water-saturated sand slug became unstable resulting in mixing of the shocked air and the granular material. By contrast, the PTFE slugs were stable at low pressures but displayed instabilities similar to the water-saturated sand slugs at higher shock pressures. The distal surfaces of the slugs remained stable under all conditions considered here. Eulerian fluid/solid interaction calculations, with the granular material modelled as a Drucker-Prager solid, reproduced the onset of the instabilities as seen in the experiments to a high level of accuracy. These calculations showed that the shock pressures to initiate instabilities increased with increasing material friction and decreasing yield strain. Moreover, the high Atwood number for this problem implied that fluid/solid interaction effects were small, and the initiation of the instability is adequately captured by directly applying a pressure on the slug surface. Lagrangian calculations with the directly applied pressures demonstrated that the instability was caused by spatial pressure gradients created by initial surface perturbations. Surface instabilities are also shown to exist in shock loaded rear-supported granular slugs: these experiments and calculations are used to infer the velocity that free-standing slugs need to acquire to initiate instabilities on their front surfaces. The results presented here, while in an idealised one-dimensional setting, provide physical understanding of the conditions required to

  16. Bifurcation from stable holes to replicating holes in vibrated dense suspensions.

    Science.gov (United States)

    Ebata, H; Sano, M

    2013-11-01

    In vertically vibrated starch suspensions, we observe bifurcations from stable holes to replicating holes. Above a certain acceleration, finite-amplitude deformations of the vibrated surface continue to grow until void penetrates fluid layers, and a hole forms. We studied experimentally and theoretically the parameter dependence of the holes and their stabilities. In suspensions of small dispersed particles, the circular shapes of the holes are stable. However, we find that larger particles or lower surface tension of water destabilize the circular shapes; this indicates the importance of capillary forces acting on the dispersed particles. Around the critical acceleration for bifurcation, holes show intermittent large deformations as a precursor to hole replication. We applied a phenomenological model for deformable domains, which is used in reaction-diffusion systems. The model can explain the basic dynamics of the holes, such as intermittent behavior, probability distribution functions of deformation, and time intervals of replication. Results from the phenomenological model match the linear growth rate below criticality that was estimated from experimental data.

  17. Structural stability and the electronic and magnetic properties of ferrimagnetic Mn_4N(0 0 1) surfaces

    International Nuclear Information System (INIS)

    Guerrero-Sánchez, J.; Takeuchi, Noboru

    2017-01-01

    Highlights: • Surface formation energy calculations demonstrate a N-dependent stability. • The magnetic alignment of these surfaces remains bulk-like, in a ferrimagnetic fashion. • A ferrimagnetic behavior in both structures is confirmed by density of states calculations. - Abstract: We have carried out spin-polarized first principles calculations to describe the surface stability and the electronic and magnetic properties of Mn_4N(0 0 1) surfaces. Results show two different surface terminations with different N content. The surface formation energies indicate that for manganese rich conditions the most stable structure is a MnN terminated surface. Whereas, from intermediate to nitrogen rich conditions, a MnN terminated surface with excess of nitrogen atoms is the most favorable. The stability of these surfaces can be traced to the formation of Mn–N bonds at the surface. The stable surfaces are Ferrimagnetic along the direction perpendicular to the surface, retaining a bulk-like behavior. However, there is a decrease in the Mn magnetic moments due to the presence of the surface. Density of states shows an asymmetric behavior, inherent of a Ferrimagnetic state. Finally, the surfaces are metallic with the main contributions around the Fermi level coming from the Mn-d orbitals. The knowledge about the atomic arrangements of the Mn_4N surfaces may serve to explain and understand the formation of more complex and technologically applicable ferromagnetic/ferrimagnetic and antiferromagnetic/ferrimagnetic heterostructures.

  18. Structural stability and the electronic and magnetic properties of ferrimagnetic Mn{sub 4}N(0 0 1) surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Guerrero-Sánchez, J., E-mail: guerrero@cnyn.unam.mx; Takeuchi, Noboru

    2017-06-15

    Highlights: • Surface formation energy calculations demonstrate a N-dependent stability. • The magnetic alignment of these surfaces remains bulk-like, in a ferrimagnetic fashion. • A ferrimagnetic behavior in both structures is confirmed by density of states calculations. - Abstract: We have carried out spin-polarized first principles calculations to describe the surface stability and the electronic and magnetic properties of Mn{sub 4}N(0 0 1) surfaces. Results show two different surface terminations with different N content. The surface formation energies indicate that for manganese rich conditions the most stable structure is a MnN terminated surface. Whereas, from intermediate to nitrogen rich conditions, a MnN terminated surface with excess of nitrogen atoms is the most favorable. The stability of these surfaces can be traced to the formation of Mn–N bonds at the surface. The stable surfaces are Ferrimagnetic along the direction perpendicular to the surface, retaining a bulk-like behavior. However, there is a decrease in the Mn magnetic moments due to the presence of the surface. Density of states shows an asymmetric behavior, inherent of a Ferrimagnetic state. Finally, the surfaces are metallic with the main contributions around the Fermi level coming from the Mn-d orbitals. The knowledge about the atomic arrangements of the Mn{sub 4}N surfaces may serve to explain and understand the formation of more complex and technologically applicable ferromagnetic/ferrimagnetic and antiferromagnetic/ferrimagnetic heterostructures.

  19. Evaluating cleansing effects on trace elements and stable isotope values in feathers of oiled birds.

    Science.gov (United States)

    Valladares, Sonia; Moreno, Roćio; Jover, Lluis; Sanpera, Carola

    2010-01-01

    Feathers of seabirds are widely used as a nondestructive tissue for pollution monitoring of trace elements, as well as convenient samples for trophic ecology studies by means of stable isotope analysis (SIA). Nevertheless, feathers can be occasionally impregnated with oil from deliberate ship discharges and from massive oil spill accidents. The feather structure makes them effective traps for particles and are subject to external contamination. It is unknown to what extent the oil adhered to feathers can change trace element concentrations or stable isotope signatures. This study has two primary objectives: (1) to assess if there are differences between trace element concentrations and stable isotope signatures of oiled and clean feathers, and (2) to determine if the cleansing of oiled feathers using commonly applied techniques such as sodium hydroxide (NaOH) washes in combination with an organic solvent (hexane) is more effective than using NaOH alone. In order to do this, we analysed trace elements (Se, Hg, Pb, Cu and Zn) and stable isotopes (delta(13)C and delta(15)N) of individual feathers of yellow-legged gulls (Larus michahellis) which were affected by the 2002 Prestige oil spill in Galicia (NW Spain). Two sets of feathers were analysed, one group were oil-free (Control group) and the other had oil adhered to its surface (Oiled group). We expected to find differences between control and oiled feathers when cleaning exclusively with NaOH and no differences when using hexane. Our results did not show significant differences between Control and Oiled groups as a consequence of the cleansing method used. Unexpectedly, the additional cleansing with hexane resulted in decreasing selenium concentrations and increasing zinc and delta(15)N values in all groups of feathers.

  20. Myocardial perfusion SPECT in stable angina;Place de la scintigraphie myocardique dans l'angor stable

    Energy Technology Data Exchange (ETDEWEB)

    Jau, P.; Jacob, T. [HP Clairval, Service de medecine nucleaire, 13 - Marseille (France); Lecorff, G.; Bouvier, J.L.; Novella, P.; Bechet, V.; Pelet, V. [HP Clairval, Service de cardiologie, 13 - Marseille (France)

    2010-03-15

    We study the precise contribution of myocardial scintigraphy in the therapeutic management of stable coronary artery disease. Until recently, treatment was focused on revascularization, often by coronary angioplasty.Recent studies have challenged this practice by showing the absence of superiority of angioplasty compared to optimal medical therapy.The problem now is to define for each stable coronary artery disease, and individually, the best of both treatment options. In this spirit, the functional approach to coronary artery disease by myocardial perfusion scintigraphy is most interesting.The diagnostic performance, including sensitivity and negative predictive value, and the prognostic value of the technique are clearly established. Recent studies show that a therapeutic decision based on a functional approach to the patient is valid.We need to know this development in cardiology for best position in the multidisciplinary discussions, myocardial scintigraphy as a functional approach to stable coronary artery disease. (N.C.)

  1. Complexation of carboxylate on smectite surfaces.

    Science.gov (United States)

    Liu, Xiandong; Lu, Xiancai; Zhang, Yingchun; Zhang, Chi; Wang, Rucheng

    2017-07-19

    We report a first principles molecular dynamics (FPMD) study of carboxylate complexation on clay surfaces. By taking acetate as a model carboxylate, we investigate its inner-sphere complexes adsorbed on clay edges (including (010) and (110) surfaces) and in interlayer space. Simulations show that acetate forms stable monodentate complexes on edge surfaces and a bidentate complex with Ca 2+ in the interlayer region. The free energy calculations indicate that the complexation on edge surfaces is slightly more stable than in interlayer space. By integrating pK a s and desorption free energies of Al coordinated water calculated previously (X. Liu, X. Lu, E. J. Meijer, R. Wang and H. Zhou, Geochim. Cosmochim. Acta, 2012, 81, 56-68; X. Liu, J. Cheng, M. Sprik, X. Lu and R. Wang, Geochim. Cosmochim. Acta, 2014, 140, 410-417), the pH dependence of acetate complexation has been revealed. It shows that acetate forms inner-sphere complexes on (110) in a very limited mildly acidic pH range while it can complex on (010) in the whole common pH range. The results presented in this study form a physical basis for understanding the geochemical processes involving clay-organics interactions.

  2. Low potential stable glucose detection at dendrimers modified polyaniline nanotubes

    Directory of Open Access Journals (Sweden)

    Alessandra Nogueira Santos

    2010-03-01

    Full Text Available The utilization of nanostructured materials for development of biosensors is a growing field in medical diagnostics. In this work a glucose biosensor based on bioactive polyglycerol (PGLD and chitosan dendrimers (CHD was developed. PGLD and CHD were bioconjugated with the enzyme glucose oxidase (GOx to obtain dendrimers with glucose sensing properties. Polyaniline nanotubes (PANINT´s were used as electron mediator due to their high ability to promote electron-transfer reactions involving GOx. The PGLD-GOx and CHD-GOx were entrapped in PANINT´s during template electrochemical polymerization of aniline. The prepared PGLD-GOx/PANINT´s and CHD-GOx/PANINT´s biosensors exhibit a strong and stable amperometric response to glucose even at a low potential of +100 mV. The based PGLD-GOx/PANINT´s and CHD-GOx/PANINT´s biosensors showed a good performance in glucose concentrations range in human blood. A comparison of the sensitivities to glucose showed that both biosensors have a linearity range between 0.02 and 10 mM, though PGLD-GOx/PANINT´s is more sensitive (10.41 vs. 7.04 nA.mM-1. The difference in the biosensor behavior and the high sensitivity of the PGLD-GOx/PANINT´s may be due to the specific organization of GOx layer at surface of the modifier macromolecule PGLD and their distribution in PANINT´s. The enzyme affinity for the substrate, K Mapp remains quite good after GOx immobilization on PGLD and CHD dendrimers and entrapment of the bioconjugates in PANINT´s.

  3. Chromium Stable Isotope Fractionation - An Indicator of Hexavalent Chromium Reduction.

    Science.gov (United States)

    Ellis, A.; Johnson, T. M.; Bullen, T. D.

    2001-12-01

    Chromium is a common anthropogenic contaminant in surface water and ground water, and is also of interest in oceanography. It is redox-active; the two common valences in natural waters are Cr(VI), which is highly soluble and toxic, and Cr(III), which is relatively insoluble. Redox reactions thus control Cr mobility in aqueous solutions, and reduction of Cr(VI) to Cr(III) is the most important reaction controlling attenuation of Cr in groundwater. Our results show that Cr(VI) reduction favors the lighter isotopes and leads to enrichment of heavier isotopes in the remaining Cr(VI). Cr isotope measurements thus show great promise as indicators of Cr(VI) reduction. We report here the first measurements of the magnitude of Cr isotope fractionation during Cr(VI) reduction and variations in δ 53Cr values obtained from three contaminated sites. Experiments were conducted to measure Cr isotope fractionation during Cr(VI) reduction by suspensions of magnetite and unamended sediments from a local pond, Urbana, IL and San Francisco Estuary near Martinez, CA. Suspensions were incubated anaerobically with constant shaking, and complete Cr(VI) reduction occurred within a few days. Cr(VI) from intermediate time points in the experiments was purified via ion exchange and 53Cr/52Cr ratios were measured via TIMS with a double isotope spike. The instantaneous per mil fractionation, ɛ , was calculated assuming a Rayleigh fractionation model. The ɛ for Cr(VI) reduction on magnetite surfaces yielded a fractionation of -3.5 ‰ . The ɛ values for the pond and estuary sediments were -3.5 ‰ and -3.3 ‰ respectively. The size of this Cr isotope fractionation is encouraging, as current precision is 0.2 \\permil. δ 53Cr values in dissolved Cr(VI) from three contaminated sites range from 1.1 ‰ to 5.8 ‰ , suggesting that Cr(VI) reduction has occurred and has induced isotopic fractionation in these settings. δ 53Cr values measured from Cr(VI) in plating baths show little or no

  4. Processes of H{sub 2} adsorption on Fe(1 1 0) surface: A density functional theory study

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Weiwei; Peng, Liang; Peng, Daoling [Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Gu, Feng Long, E-mail: gu@scnu.edu.cn [Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Liu, Jun [Material Design and Simulation Technology Co. Ltd., Room 1716, V-Faction, 10 Vanke, 2 Ring Road of North Section, Chengdu (China)

    2014-03-01

    Highlights: • The hydrogen coverages for H{sub 2} adsorption on Fe(1 1 0) surface ranging from 0.125 to 1.000 are prepared by using different surface supercells. • With the reduction of coverage, the average iron atomic energy is increased and the adsorption energy is decreased, leading to the system more stable; while coverage has little effect on the Fe(1 1 0) surface structure and the hydrogen adsorption process. • The most stable absorption site is found to be the on-top site. • DFT calculations show that it is a weak adsorption and the adsorption energy barriers under 4.4 kcal/mol. • The final state is H{sub 2} molecule dissociated into two hydrogen atoms interacting with surface iron atoms to form stable Fe-H bonds. - Abstract: Processes of H{sub 2} adsorption on Fe(1 1 0) surface have been studied by the density functional theory, properties such as surface structure, adsorption position, and adsorption energies are discussed as well. To investigate the atomic geometries and stability under different hydrogen coverages for this adsorption, the hydrogen coverages ranging from 0.125 to 1.000 are prepared by using different surface supercells. It is found that with the reduction of coverage, the average iron atomic energy and the adsorption energy are increased, leading to the system more stable; while coverage has little effect on the Fe(1 1 0) surface structure and the hydrogen adsorption process. The most stable absorption site is found to be the on-top site. Our calculations show that it is a weak adsorption and the adsorption energy barriers under 4.4 kcal/mol. The final state is H{sub 2} molecule dissociated into two hydrogen atoms and interacting with surface iron atoms to form stable Fe-H bonds.

  5. Prolate dominant but oblate stable

    International Nuclear Information System (INIS)

    Girija, K.K.; Joseph, Antony

    2013-01-01

    This article discusses the yrast states of even-even nuclei in the isotopic chains 150-160 Dy, 150-160 Er and 150-160 Yb and thereby to study the shape and deformation dependence of ground state energy, exploring cranked Nilsson Strutinsky shell correction method and potential energy surface (PES) diagrams. The total energy calculations have been performed for the even-even nuclei of the isotopic chains 150-160 Dy, 150-160 Er and 150-160 Yb in the ground state. The range of triaxiality parameter used is 0-60 ° and a frequency range of 0-1.5 MeV is employed. The quadrupole deformation parameter ε 2 is varied from 0 to 1

  6. Evaporation and abstraction determined from stable isotopes during normal flow on the Gariep River, South Africa

    Science.gov (United States)

    Diamond, Roger E.; Jack, Sam

    2018-04-01

    Changes in the stable isotope composition of water can, with the aid of climatic parameters, be used to calculate the quantity of evaporation from a water body. Previous workers have mostly focused on small, research catchments, with abundant data, but of limited scope. This study aimed to expand such work to a regional or sub-continental scale. The first full length isotope survey of the Gariep River quantifies evaporation on the river and the man-made reservoirs for the first time, and proposes a technique to calculate abstraction from the river. The theoretically determined final isotope composition for an evaporating water body in the given climate lies on the empirically determined local evaporation line, validating the assumptions and inputs to the Craig-Gordon evaporation model that was used. Evaporation from the Gariep River amounts to around 20% of flow, or 40 m3/s, of which about half is due to evaporation from the surface of the Gariep and Vanderkloof Reservoirs, showing the wastefulness of large surface water impoundments. This compares well with previous estimates based on evapotranspiration calculations, and equates to around 1300 GL/a of water, or about the annual water consumption of Johannesburg and Pretoria, where over 10 million people reside. Using similar evaporation calculations and applying existing transpiration estimates to a gauged length of river, the remaining quantity can be attributed to abstraction, amounting to 175 L/s/km in the lower middle reaches of the river. Given that high water demand and climate change are global problems, and with the challenges of maintaining water monitoring networks, stable isotopes are shown to be applicable over regional to national scales for modelling hydrological flows. Stable isotopes provide a complementary method to conventional flow gauging for understanding hydrology and management of large water resources, particularly in arid areas subject to significant evaporation.

  7. Inkjet printing for direct micropatterning of a superhydrophobic surface: Toward biomimetic fog harvesting surfaces

    KAUST Repository

    Zhang, Lianbin

    2015-01-01

    The preparation of biomimetic superhydrophobic surfaces with hydrophilic micro-sized patterns is highly desirable, but a one-step, mask-free method to produce such surfaces has not previously been reported. We have developed a direct method to produce superhydrophilic micropatterns on superhydrophobic surfaces based on inkjet printing technology. This work was inspired by the efficient fog-harvesting behavior of Stenocara beetles in the Namib Desert. A mussel-inspired ink consisting of an optimized solution of dopamine was applied directly by inkjet printing to superhydrophobic surfaces. Stable Wenzel\\'s microdroplets of the dopamine solution with well-defined micropatterns were obtained on these surfaces. Superhydrophilic micropatterns with well-controlled dimensions were then readily achieved on the superhydrophobic surfaces by the formation of polydopamine via in situ polymerization. The micropatterned superhydrophobic surfaces prepared by this inkjet printing method showed enhanced water collection efficiency compared with uniform superhydrophilic and superhydrophobic surfaces. This method can be used for the facile large-scale patterning of superhydrophobic surfaces with high precision and superior pattern stability and is therefore a key step toward patterning superhydrophobic surfaces for practical applications. This journal is

  8. A comparison of stable platform and strapdown airborne gravity

    DEFF Research Database (Denmark)

    Glennie, C.L.; Schwarz, K.P.; Bruton, A.M.

    2000-01-01

    To date, operational airborne gravity results have been obtained using either a damped two-axis stable platform gravimeter system such as the LaCoste and Romberg (LCR) S-model marine gravimeter or a strapdown inertial navigation system (INS), showing comparable accuracies. In June 1998 three flight...

  9. A well-defined mesoporous amine silica surface via a selective treatment of SBA-15 with ammonia

    KAUST Repository

    Bendjeriou-Sedjerari, Anissa; Pelletier, Jeremie; Abou-Hamad, Edy; Emsley, Lyndon; Basset, Jean-Marie

    2012-01-01

    2D double-quantum 1H- 1H NMR unambiguously shows that the "isolated" Si-OH surface silanols of dehydroxylated SBA-15 are converted upon treatment with ammonia into single silylamine surface site Si-NH 2. The "gem" di-silanols (Si(OH) 2) remain intact. Treatment using HMDS produces (Si(OSiMe 3) 2) but leaves Si-NH 2 untouched. The resulting surface is hydrophobic and stable. © The Royal Society of Chemistry 2012.

  10. Stable isotope customer list and summary of shipments: FY 1975

    International Nuclear Information System (INIS)

    Davis, W.C.

    1975-10-01

    This compilation is published as an aid to those concerned with the separation and sale of stable isotopes. The information is divided into four sections: an alphabetical list of domestic and foreign customers, showing the stable isotopes purchased during the fiscal year; an alphabetical list of isotopes, cross-referenced to customer numbers and divided into domestic and foreign categories; an alphabetical list of states and countries, cross-referenced to customer numbers and indicating geographical concentrations of isotope users; and a tabulation of the shipments, quantities, and dollars for domestic, foreign, and project categories for each isotope, with the totals for loaned isotopes shown at the end of the table. (auth)

  11. Stable isotope customer list and summary of shipments: FY 1984

    International Nuclear Information System (INIS)

    Tracy, J.G.

    1984-12-01

    This compilation is published as an aid to those concerned with the separation and sale of stable isotopes. The information is divided into four sections: (1) alphabetical list of domestic and foreign customers, showing the stable isotopes purchased during the fiscal year; (2) alphabetical list of isotopes, cross-referenced to customer numbers and divided into domestic and foreign categories; (3) alphabetical list of states and countries, cross-referenced to customer numbers and indicating geographical concentrations of isotope users; and (4) tabulation of the shipments, quantities, and dollars for domestic, foreign, and project categories for each isotope

  12. Stable isotope customer list and summary of shipments - FY 1983

    International Nuclear Information System (INIS)

    Davis, W.C.

    1983-12-01

    This compilation is published as an aid to those concerned with the separation and sale of stable isotopes. The information is divided into four sections: (1) alphabetical list of domestic and foreign customers, showing the stable isotopes purchased during the fiscal year; (2) alphabetical list of isotopes, cross-referenced to customer numbers and divided into domestic and foreign categories; (3) alphabetical list of states and countries, cross-referenced to customer numbers and indicating geographical concentrations of isotope users; and (4) tabulation of the shipments, quantities, and dollars for domestic, foreign, and project categories for each isotope

  13. Stability of skyrmions on curved surfaces in the presence of a magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho-Santos, V.L., E-mail: vagson.carvalho@usach.cl [Instituto Federal de Educação, Ciência e Tecnologia Baiano - Campus Senhor do Bonfim, Km 04 Estrada da Igara, 48970-000 Senhor do Bonfim, Bahia (Brazil); Departamento de Física, Universidad de Santiago de Chile and CEDENNA, Avda. Ecuador 3493, Santiago (Chile); Elias, R.G.; Altbir, D. [Departamento de Física, Universidad de Santiago de Chile and CEDENNA, Avda. Ecuador 3493, Santiago (Chile); Fonseca, J.M. [Universidade Federal de Viçosa, Departamento de Física, Avenida Peter Henry Rolfs s/n, 36570-000 Viçosa, MG (Brazil)

    2015-10-01

    We study the stability and energetics associated to skyrmions appearing as excitations on curved surfaces. Using a continuum model we show that the presence of cylindrically radial and azimuthal fields destabilize the skyrmions that appear in the absence of an external field. Weak fields generate fractional skyrmions while strong magnetic fields yield stable 2π-skyrmions, which have their widths diminished by the magnetic field strength. Under azimuthal fields vortex appears as stable state on the curved surface. - Highlights: • Stability of skyrmions on curved surfaces in the presence of a magnetic field. • Weak fields can destabilize skyrmions. • Strong magnetic fields yield the appearing of 2π-skyrmions. • The width of skyrmions is determined by the curvature and magnetic field strength. • Under azimuthal fields vortex appears as stable states.

  14. Geochemistry of the stable isotopes of silicon

    Energy Technology Data Exchange (ETDEWEB)

    Douthitt, C B [California Inst. of Tech., Pasadena (USA). Div. of Geological and Planetary Sciences

    1982-08-01

    One hundred thirty two new measurements of the relative abundances of the stable isotopes of silicon in terrestrial materials are presented. The total variation of delta/sup 30/Si found is 6.2 parts per thousand, centered on the mean of terrestrial mafic and ultramafic igneous rocks, delta/sup 30/Si = -0.4 parts per thousand. Igneous rocks show limited variation; coexisting minerals exhibit small, systematic silicon isotopic fractionations that are roughly 1/3 the magnitude of concomitant oxygen isotopic fractionations at 1150/sup 0/C. In both igneous minerals and rocks, delta/sup 30/Si shows a positive correlation with silicon content, as does delta/sup 18/O. Opal from both sponge spicules and sinters is light, with delta/sup 30/Si = -2.3 and -1.4 parts per thousand respectively. Large delta/sup 30/Si values of both positive and negative sign are reported for the first time from clay minerals, opaline phytoliths, and authigenic quartz. All highly fractionated samples were precipitated from solution at low temperatures; however, aqueous silicon is not measurably fractionated relative to quartz at equilibrium. A kinetic isotope fractionation of approximately 3.5 parts per thousand is postulated to occur during the low temperature precipitation of opal and, possibly, poorly ordered phyllosilicates, with the silicate phase being enriched in /sup 28/Si. This fractionation, coupled with a Rayleigh precipitation model, is capable of explaining most non-magmatic delta/sup 30/Si variations.

  15. Ranking stability and super-stable nodes in complex networks.

    Science.gov (United States)

    Ghoshal, Gourab; Barabási, Albert-László

    2011-07-19

    Pagerank, a network-based diffusion algorithm, has emerged as the leading method to rank web content, ecological species and even scientists. Despite its wide use, it remains unknown how the structure of the network on which it operates affects its performance. Here we show that for random networks the ranking provided by pagerank is sensitive to perturbations in the network topology, making it unreliable for incomplete or noisy systems. In contrast, in scale-free networks we predict analytically the emergence of super-stable nodes whose ranking is exceptionally stable to perturbations. We calculate the dependence of the number of super-stable nodes on network characteristics and demonstrate their presence in real networks, in agreement with the analytical predictions. These results not only deepen our understanding of the interplay between network topology and dynamical processes but also have implications in all areas where ranking has a role, from science to marketing.

  16. Preparation of thermally stable nanocrystalline hydroxyapatite by hydrothermal method.

    Science.gov (United States)

    Prakash Parthiban, S; Elayaraja, K; Girija, E K; Yokogawa, Y; Kesavamoorthy, R; Palanichamy, M; Asokan, K; Narayana Kalkura, S

    2009-12-01

    Thermally stable hydroxyapatite (HAp) was synthesized by hydrothermal method in the presence of malic acid. X-ray diffraction (XRD), Fourier transform infra-red spectroscopy (FT-IR), Raman spectroscopy, scanning electron microscopy (SEM), differential thermal analysis (DTA), thermogravimetric analysis (TGA) was done on the synthesized powders. These analyses confirmed the sample to be free from impurities and other phases of calcium phosphates, and were of rhombus morphology along with nanosized particles. IR and Raman analyses indicated the adsorption of malic acid on HAp. Thermal stability of the synthesized HAp was confirmed by DTA and TGA. The synthesized powders were thermally stable upto 1,400 degrees C and showed no phase change. The proposed method might be useful for producing thermally stable HAp which is a necessity for high temperature coating applications.

  17. Applications of stable isotopes in clinical pharmacology

    NARCIS (Netherlands)

    Schellekens, Reinout C A; Stellaard, Frans; Woerdenbag, Herman J; Frijlink, Henderik W; Kosterink, Jos G W

    2011-01-01

    This review aims to present an overview of the application of stable isotope technology in clinical pharmacology. Three main categories of stable isotope technology can be distinguished in clinical pharmacology. Firstly, it is applied in the assessment of drug pharmacology to determine the

  18. Stable isotopes and biomarkers in microbial ecology

    NARCIS (Netherlands)

    Boschker, H.T.S.; Middelburg, J.J.

    2002-01-01

    The use of biomarkers in combination with stable isotope analysis is a new approach in microbial ecology and a number of papers on a variety of subjects have appeared. We will first discuss the techniques for analysing stable isotopes in biomarkers, primarily gas chromatography-combustion-isotope

  19. Gas phase thermal diffusion of stable isotopes

    International Nuclear Information System (INIS)

    Eck, C.F.

    1979-01-01

    The separation of stable isotopes at Mound Facility is reviewed from a historical perspective. The historical development of thermal diffusion from a laboratory process to a separation facility that handles all the noble gases is described. In addition, elementary thermal diffusion theory and elementary cascade theory are presented along with a brief review of the uses of stable isotopes

  20. Effectiveness of Ivabradine in Treating Stable Angina Pectoris.

    Science.gov (United States)

    Ye, Liwen; Ke, Dazhi; Chen, Qingwei; Li, Guiqiong; Deng, Wei; Wu, Zhiqin

    2016-04-01

    Many studies show that ivabradine is effective for stable angina.This meta-analysis was performed to determine the effect of treatment duration and control group type on ivabradine efficacy in stable angina pectoris.Relevant articles in the English language in the PUBMED and EMBASE databases and related websites were identified by using the search terms "ivabradine," "angina," "randomized controlled trials," and "Iva." The final search date was November 2, 2015.Articles were included if they were published randomized controlled trials that related to ivabradine treatment of stable angina pectoris.Patients with stable angina pectoris were included.The patients were classified according to treatment duration (Angina outcomes were heart rate at rest or peak, exercise duration, and time to angina onset.Seven articles were selected. There were 3747 patients: 2100 and 1647 were in the ivabradine and control groups, respectively. The ivabradine group had significantly longer exercise duration when they had been treated for at least 3 months, but not when treatment time was less than 3 months. Ivabradine significantly improved time to angina onset regardless of treatment duration. Control group type did not influence the effect of exercise duration (significant) or time to angina onset (significant).Compared with beta-blocker and placebo, ivabradine improved exercise duration and time to onset of angina in patients with stable angina. However, its ability to improve exercise duration only became significant after at least 3 months of treatment.

  1. Surface Water & Surface Drainage

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — This data set contains boundaries for all surface water and surface drainage for the state of New Mexico. It is in a vector digital data structure digitized from a...

  2. Structure of acid-stable carmine.

    Science.gov (United States)

    Sugimoto, Naoki; Kawasaki, Yoko; Sato, Kyoko; Aoki, Hiromitsu; Ichi, Takahito; Koda, Takatoshi; Yamazaki, Takeshi; Maitani, Tamio

    2002-02-01

    Acid-stable carmine has recently been distributed in the U.S. market because of its good acid stability, but it is not permitted in Japan. We analyzed and determined the structure of the major pigment in acid-stable carmine, in order to establish an analytical method for it. Carminic acid was transformed into a different type of pigment, named acid-stable carmine, through amination when heated in ammonia solution. The features of the structure were clarified using a model compound, purpurin, in which the orientation of hydroxyl groups on the A ring of the anthraquinone skeleton is the same as that of carminic acid. By spectroscopic means and the synthesis of acid-stable carmine and purpurin derivatives, the structure of the major pigment in acid-stable carmine was established as 4-aminocarminic acid, a novel compound.

  3. Nitride surface passivation of GaAs nanowires: impact on surface state density.

    Science.gov (United States)

    Alekseev, Prokhor A; Dunaevskiy, Mikhail S; Ulin, Vladimir P; Lvova, Tatiana V; Filatov, Dmitriy O; Nezhdanov, Alexey V; Mashin, Aleksander I; Berkovits, Vladimir L

    2015-01-14

    Surface nitridation by hydrazine-sulfide solution, which is known to produce surface passivation of GaAs crystals, was applied to GaAs nanowires (NWs). We studied the effect of nitridation on conductivity and microphotoluminescence (μ-PL) of individual GaAs NWs using conductive atomic force microscopy (CAFM) and confocal luminescent microscopy (CLM), respectively. Nitridation is found to produce an essential increase in the NW conductivity and the μ-PL intensity as well evidence of surface passivation. Estimations show that the nitride passivation reduces the surface state density by a factor of 6, which is of the same order as that found for GaAs/AlGaAs nanowires. The effects of the nitride passivation are also stable under atmospheric ambient conditions for six months.

  4. Modelling of the flow of stable air over a complex region

    CSIR Research Space (South Africa)

    Scholtz, MT

    1976-01-01

    Full Text Available The flow of stable air over a general region of complex topography and non-uniform surface temperature has been investigated. In order to gain further understanding of the motion of surface air, it was necessary to study the vertical structure...

  5. Surface zwitterionization: Effective method for preventing oral bacterial biofilm formation on hydroxyapatite surfaces

    Science.gov (United States)

    Lee, Myoungjin; Kim, Heejin; Seo, Jiae; Kang, Minji; Kang, Sunah; Jang, Joomyung; Lee, Yan; Seo, Ji-Hun

    2018-01-01

    In this study, we conducted surface zwitterionization of hydroxyapatite (HA) surfaces by immersing them in the zwitterionic polymer solutions to provide anti-bacterial properties to the HA surface. Three different monomers containing various zwitterionic groups, i.e., phosphorylcholine (PC), sulfobetaine (SB), and carboxybetaine (CB), were copolymerized with the methacrylic monomer containing a Ca2+-binding moiety, using the free radical polymerization method. As a control, functionalization of the copolymer containing the Ca2+-binding moiety was synthesized using a hydroxy group. The stable immobilization of the zwitterionic functional groups was confirmed by water contact angle analysis and X-ray photoelectron spectroscopy (XPS) measurement conducted after the sonication process. The zwitterionized HA surface showed significantly decreased protein adsorption, whereas the hydroxyl group-coated HA surface showed limited efficacy. The anti-bacterial adhesion property was confirmed by conducting Streptococcus mutans (S. mutans) adhesion tests for 6 h and 24 h. When furanone C-30, a representative anti-quorum sensing molecule for S. mutans, was used, only a small amount of bacteria adhered after 6 h and the population did not increase after 24 h. In contrast, zwitterionized HA surfaces showed almost no bacterial adhesion after 6 h and the effect was retained for 24 h, resulting in the lowest level of oral bacterial adhesion. These results confirm that surface zwitterionization is a promising method to effectively prevent oral bacterial adhesion on HA-based materials.

  6. Showing Area Matters: A Work of Friction

    Science.gov (United States)

    Van Domelen, David

    2010-01-01

    Typically, we teach the simplified friction equation of the form F[subscript s] = [mu][subscript s]N for static friction, where F[subscript s] is the maximum static friction, [mu][subscript s] is the coefficient of static friction, and "N" is the normal force pressing the surfaces together. However, this is a bit too simplified, and…

  7. Dynamics and control of twisting bi-stable structures

    Science.gov (United States)

    Arrieta, Andres F.; van Gemmeren, Valentin; Anderson, Aaron J.; Weaver, Paul M.

    2018-02-01

    Compliance-based morphing structures have the potential to offer large shape adaptation, high stiffness and low weight, while reducing complexity, friction, and scalability problems of mechanism based systems. A promising class of structure that enables these characteristics are multi-stable structures given their ability to exhibit large deflections and rotations without the expensive need for continuous actuation, with the latter only required intermittently. Furthermore, multi-stable structures exhibit inherently fast response due to the snap-through instability governing changes between stable states, enabling rapid configuration switching between the discrete number of programmed shapes of the structure. In this paper, the design and utilisation of the inherent nonlinear dynamics of bi-stable twisting I-beam structures for actuation with low strain piezoelectric materials is presented. The I-beam structure consists of three compliant components assembled into a monolithic single element, free of moving parts, and showing large deflections between two stable states. Finite element analysis is utilised to uncover the distribution of strain across the width of the flange, guiding the choice of positioning for piezoelectric actuators. In addition, the actuation authority is maximised by calculating the generalised coupling coefficient for different positions of the piezoelectric actuators. The results obtained are employed to tailor and test I-beam designs exhibiting desired large deflection between stable states, while still enabling the activation of snap-through with the low strain piezoelectric actuators. To this end, the dynamic response of the I-beams to piezoelectric excitation is investigated, revealing that resonant excitations are insufficient to dynamically trigger snap-through. A novel bang-bang control strategy, which exploits the nonlinear dynamics of the structure successfully triggers both single and constant snap-through between the stable states

  8. Stable walking with asymmetric legs

    International Nuclear Information System (INIS)

    Merker, Andreas; Rummel, Juergen; Seyfarth, Andre

    2011-01-01

    Asymmetric leg function is often an undesired side-effect in artificial legged systems and may reflect functional deficits or variations in the mechanical construction. It can also be found in legged locomotion in humans and animals such as after an accident or in specific gait patterns. So far, it is not clear to what extent differences in the leg function of contralateral limbs can be tolerated during walking or running. Here, we address this issue using a bipedal spring-mass model for simulating walking with compliant legs. With the help of the model, we show that considerable differences between contralateral legs can be tolerated and may even provide advantages to the robustness of the system dynamics. A better understanding of the mechanisms and potential benefits of asymmetric leg operation may help to guide the development of artificial limbs or the design novel therapeutic concepts and rehabilitation strategies.

  9. Development of stable isotope manufacturing in Russia

    International Nuclear Information System (INIS)

    Pokidychev, A.; Pokidycheva, M.

    1999-01-01

    For the past 25 years, Russia has relied heavily on the electromagnetic separation process for the production of middle and heavy mass stable isotopes. The separation of most light isotopes had been centered in Georgia which, after the collapse of the USSR, left Russia without this capability. In the mid-1970s, development of centrifuge technology for the separation of stable isotopes was begun. Alternative techniques such as laser separation, physical-chemical methods, and ion cyclotron resonance have also been investigated. Economic considerations have played a major role in the development and current status of the stable isotope enrichment capabilities of Russia

  10. Stable Isotope Group 1984 progress report

    International Nuclear Information System (INIS)

    Lyon, G.L.

    1985-04-01

    The work of the group in 1984 is described and includes studies in isotope geology, isotope hydrology, geochronology, isotope biology and mass spectrometer instrumentation. Geothermal studies have decreased compared to other years, but major data summaries were made for Wairakei and Ngawha. The hydrology of Whakarewarewa and Rotorua is being elucidated using water isotopes. Models of the subsurface flows at Kawerau and Ngawha are being made to relate fluid to mineral isotope compositions. A study of the δ 13 C and δ 34 S compositions of New Zealand oils has been started. Groups of oils of related origin are being defined, and compositions will be compared with those of potential source rocks. A method was developed for isotope analysis of sulphur in rocks. The isotopic composition of water is being used to identify and characterise groundwater aquifers in the Wairarapa and at Poverty Bay. Stable carbon isotopes have been used to identify food sources for invertebrates, and to show biochemical pathways in lactation by cows. The geochronology group is involved in major studies in Antarctica, using U-Pb, Rb-Sr and K-Ar methods. Rocks from North Victoria Land, Marie Byrd Land and the USARP mountains are being compared with possible correlatives in New Zealand and Argentina. Strontium isotope data is being applied to the origin of magmas in several regions of New Zealand. The K-Ar data is being stored on computer files. Fission track measurements are being applied to unravel uplift histories in Westland and Taranaki

  11. ROBUST MPC FOR STABLE LINEAR SYSTEMS

    Directory of Open Access Journals (Sweden)

    M.A. Rodrigues

    2002-03-01

    Full Text Available In this paper, a new model predictive controller (MPC, which is robust for a class of model uncertainties, is developed. Systems with stable dynamics and time-invariant model uncertainty are treated. The development herein proposed is focused on real industrial systems where the controller is part of an on-line optimization scheme and works in the output-tracking mode. In addition, the system has a time-varying number of degrees of freedom since some of the manipulated inputs may become constrained. Moreover, the number of controlled outputs may also vary during system operation. Consequently, the actual system may show operating conditions with a number of controlled outputs larger than the number of available manipulated inputs. The proposed controller uses a state-space model, which is aimed at the representation of the output-predicted trajectory. Based on this model, a cost function is proposed whereby the output error is integrated along an infinite prediction horizon. It is considered the case of multiple operating points, where the controller stabilizes a set of models corresponding to different operating conditions for the system. It is shown that closed-loop stability is guaranteed by the feasibility of a linear matrix optimization problem.

  12. Minute synthesis of extremely stable gold nanoparticles.

    Science.gov (United States)

    Zhou, Min; Wang, Baoxiang; Rozynek, Zbigniew; Xie, Zhaohui; Fossum, Jon Otto; Yu, Xiaofeng; Raaen, Steinar

    2009-12-16

    We describe a rapid environmentally friendly wet-chemical approach to synthesize extremely stable non-toxic, biocompatible, water-soluble monodispersed gold nanoparticles (AuNPs) in one step at room temperature. The particles have been successfully achieved in just a few minutes by merely adding sodium hydroxide (NaOH) acting as an initiator for the reduction of HAuCl(4) in aqueous solution in the presence of polyvinylpyrrolidone (PVP) without the use of any reducing agent. It is also proved to be highly efficient for the preparation of AuNPs with controllable sizes. The AuNPs show remarkable stability in water media with high concentrations of salt, various buffer solutions and physiological conditions in biotechnology and biomedicine. Moreover, the AuNPs are also non-toxic at high concentration (100 microM). Therefore, it provides great opportunities to use these AuNPs for biotechnology and biomedicine. This new approach also involved several green chemistry concepts, such as the selection of environmentally benign reagents and solvents, without energy consumption, and less reaction time.

  13. Minute synthesis of extremely stable gold nanoparticles

    International Nuclear Information System (INIS)

    Zhou Min; Wang Baoxiang; Rozynek, Zbigniew; Xie Zhaohui; Fossum, Jon Otto; Yu Xiaofeng; Raaen, Steinar

    2009-01-01

    We describe a rapid environmentally friendly wet-chemical approach to synthesize extremely stable non-toxic, biocompatible, water-soluble monodispersed gold nanoparticles (AuNPs) in one step at room temperature. The particles have been successfully achieved in just a few minutes by merely adding sodium hydroxide (NaOH) acting as an initiator for the reduction of HAuCl 4 in aqueous solution in the presence of polyvinylpyrrolidone (PVP) without the use of any reducing agent. It is also proved to be highly efficient for the preparation of AuNPs with controllable sizes. The AuNPs show remarkable stability in water media with high concentrations of salt, various buffer solutions and physiological conditions in biotechnology and biomedicine. Moreover, the AuNPs are also non-toxic at high concentration (100 μM). Therefore, it provides great opportunities to use these AuNPs for biotechnology and biomedicine. This new approach also involved several green chemistry concepts, such as the selection of environmentally benign reagents and solvents, without energy consumption, and less reaction time.

  14. Crystal engineering of stable temozolomide cocrystals.

    Science.gov (United States)

    Babu, N Jagadeesh; Sanphui, Palash; Nangia, Ashwini

    2012-10-01

    The antitumor prodrug temozolomide (TMZ) decomposes in aqueous medium of pH≥7 but is relatively stable under acidic conditions. Pure TMZ is obtained as a white powder but turns pink and then brown, which is indicative of chemical degradation. Pharmaceutical cocrystals of TMZ were engineered with safe coformers such as oxalic acid, succinic acid, salicylic acid, d,l-malic acid, and d,l-tartaric acid, to stabilize the drug as a cocrystal. All cocrystals were characterized by powder X-ray diffraction (PXRD), single crystal X-ray diffraction, and FT-IR as well as FT-Raman spectroscopy. Temozolomide cocrystals with organic acids (pK(a) 2-6) were found to be more stable than the reference drug under physiological conditions. The half-life (T(1/2)) of TMZ-oxalic and TMZ-salicylic acid measured by UV/Vis spectroscopy in pH 7 buffer is two times longer than that of TMZ (3.5 h and 3.6 h vs. 1.7 h); TMZ-succinic acid, TMZ-tartaric acid, and TMZ-malic acid also exhibited a longer half-life (2.3, 2.5, and 2.8 h, respectively). Stability studies at 40 °C and 75 % relative humidity (ICH conditions) showed that hydrolytic degradation of temozolomide in the solid state started after one week, as determined by PXRD, whereas its cocrystals with succinic acid and oxalic acid were intact at 28 weeks, thus confirming the greater stability of cocrystals compared to the reference drug. The intrinsic dissolution rate (IDR) profile of TMZ-oxalic acid and TMZ-succinic acid cocrystals in buffer of pH 7 is comparable to that of temozolomide. Among the temozolomide cocrystals examined, those with succinic acid and oxalic acid exhibited both an improved stability and a comparable dissolution rate to the reference drug. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Stable nuclear transformation of Eudorina elegans

    Directory of Open Access Journals (Sweden)

    Lerche Kai

    2013-02-01

    inducible expression of the co-bombarded gluc gene was demonstrated by transcription analysis and bioluminescence assays. Conclusions Heterologous flanking sequences, including promoters, work in E. elegans and permit both constitutive and inducible expression of heterologous genes. Stable nuclear transformation of E. elegans is now routine. Thus, we show that genetic engineering of a species is possible even without the resources of endogenous genes and promoters.

  16. Adsorption-Driven Surface Segregation of the Less Reactive Alloy Component

    DEFF Research Database (Denmark)

    Andersson, Klas Jerker; Calle Vallejo, Federico; Rossmeisl, Jan

    2009-01-01

    Counterintuitive to expectations and all prior observations of adsorbate-induced surface segregation of the more reactive alloy component (the one forming the stronger bond with the adsorbate), we show that CO adsorption at elevated pressures and temperatures pulls the less reactive Cu to the sur......Counterintuitive to expectations and all prior observations of adsorbate-induced surface segregation of the more reactive alloy component (the one forming the stronger bond with the adsorbate), we show that CO adsorption at elevated pressures and temperatures pulls the less reactive Cu...... to the surface of a CuPt near-surface alloy. The Cu surface segregation is driven by the formation of a stable self-organized CO/CuPt surface alloy structure and is rationalized in terms of the radically stronger Pt−CO bond when Cu is present in the first surface layer of Pt. The results, which are expected...

  17. Current Challenges in Understanding and Forecasting Stable Boundary Layers over Land and Ice

    Directory of Open Access Journals (Sweden)

    Gert-Jan eSteeneveld

    2014-10-01

    Full Text Available Understanding and prediction of the stable atmospheric boundary layer is challenging. Many physical processes come into play in the stable boundary layer, i.e. turbulence, radiation, land surface coupling and heterogeneity, orographic turbulent and gravity wave drag. The development of robust stable boundary-layer parameterizations for weather and climate models is difficult because of the multiplicity of processes and their complex interactions. As a result, these models suffer from biases in key variables, such as the 2-m temperature, boundary-layer depth and wind speed. This short paper briefly summarizes the state-of-the-art of stable boundary layer research, and highlights physical processes that received only limited attention so far, in particular orographically-induced gravity wave drag, longwave radiation divergence, and the land-atmosphere coupling over a snow-covered surface. Finally, a conceptual framework with relevant processes and particularly their interactions is proposed.

  18. Tracing anthropogenic inputs to production in the Seto Inland Sea, Japan - A stable isotope approach

    International Nuclear Information System (INIS)

    Miller, Todd W.; Omori, Koji; Hamaoka, Hideki; Shibata, Jun-ya; Hidejiro, Onishi

    2010-01-01

    The Seto Inland Sea (SIS) receives waste runoff from ∼24% of Japan's total population, yet it is also important in regional fisheries, recreation and commerce. During August 2006 we measured carbon and nitrogen stable isotopes of particulate organic matter (POM) and zooplankton across urban population gradients of the SIS. Results showed a consistent trend of increasing δ 15 N in POM and zooplankton from the western to eastern subsystems of the SIS, corresponding to increasing population load. Principal components analysis of environmental variables indicated high positive loadings of δ 15 N and δ 13 C with high chlorophyll-a and surface water temperatures, and negative loadings of low salinities related to inputs from large rivers and high urban development in the eastern SIS. Anthropogenic nitrogen was therefore readily integrated into the SIS food web from primary production to copepods, which are a critical food source for many commercially important fishes.

  19. A Widely Applicable Silver Sol for TLC Detection with Rich and Stable SERS Features

    Science.gov (United States)

    Zhu, Qingxia; Li, Hao; Lu, Feng; Chai, Yifeng; Yuan, Yongfang

    2016-04-01

    Thin-layer chromatography (TLC) coupled with surface-enhanced Raman spectroscopy (SERS) has gained tremendous popularity in the study of various complex systems. However, the detection of hydrophobic analytes is difficult, and the specificity still needs to be improved. In this study, a SERS-active non-aqueous silver sol which could activate the analytes to produce rich and stable spectral features was rapidly synthesized. Then, the optimized silver nanoparticles (AgNPs)-DMF sol was employed for TLC-SERS detection of hydrophobic (and also hydrophilic) analytes. SERS performance of this sol was superior to that of traditional Lee-Meisel AgNPs due to its high specificity, acceptable stability, and wide applicability. The non-aqueous AgNPs would be suitable for the TLC-SERS method, which shows great promise for applications in food safety assurance, environmental monitoring, medical diagnoses, and many other fields.

  20. Tracing anthropogenic inputs to production in the Seto Inland Sea, Japan--a stable isotope approach.

    Science.gov (United States)

    Miller, Todd W; Omori, Koji; Hamaoka, Hideki; Shibata, Jun-ya; Hidejiro, Onishi

    2010-10-01

    The Seto Inland Sea (SIS) receives waste runoff from ∼24% of Japan's total population, yet it is also important in regional fisheries, recreation and commerce. During August 2006 we measured carbon and nitrogen stable isotopes of particulate organic matter (POM) and zooplankton across urban population gradients of the SIS. Results showed a consistent trend of increasing δ(15)N in POM and zooplankton from the western to eastern subsystems of the SIS, corresponding to increasing population load. Principal components analysis of environmental variables indicated high positive loadings of δ(15)N and δ(13)C with high chlorophyll-a and surface water temperatures, and negative loadings of low salinities related to inputs from large rivers and high urban development in the eastern SIS. Anthropogenic nitrogen was therefore readily integrated into the SIS food web from primary production to copepods, which are a critical food source for many commercially important fishes. Copyright © 2010 Elsevier Ltd. All rights reserved.

  1. Stable Isotope Group 1982 progress report

    International Nuclear Information System (INIS)

    Stewart, M.K.

    1983-06-01

    The work of the Stable Isotope Group of the Institute of Nuclear Sciences during 1982, in the fields of isotope geology, isotope hydrology, geochronology, isotope biology and mass spectrometer instrumentation, is described

  2. Bartolome Island, Galapagos Stable Oxygen Calibration Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Galapagos Coral Stable Oxygen Calibration Data. Sites: Bartolome Island: 0 deg, 17'S, 90 deg 33' W. Champion Island: 1 deg, 15'S, 90 deg, 05' W. Urvina Bay (Isabela...

  3. Stable Isotope Group 1983 progress report

    International Nuclear Information System (INIS)

    Stewart, M.K.

    1984-06-01

    The work of the Stable Isotope Group of the Institute of Nuclear Sciences in the fields of isotope geology, isotope hydrology, geochronology, isotope biology and related fields, and mass spectrometer instrumentation, during 1983, is described

  4. Fabrication and characterization of stable superhydrophobic fluorinated-polyacrylate/silica hybrid coating

    International Nuclear Information System (INIS)

    Li, Kunquan; Zeng, Xingrong; Li, Hongqiang; Lai, Xuejun

    2014-01-01

    Graphical abstract: - Highlights: • The superhydrophobic PFA/SiO 2 coating was successfully fabricated by spraying. • The synthesized PFA latex showed core–shell structure and good dispersion. • The PFA/SiO 2 coating showed good resistance to acid and base, weather and heat. • The superhydrophobic coating could be fabricated on various substrates. - Abstract: The core–shell fluorinated-polyacrylate (PFA) emulsion was synthesized through emulsion polymerization method and the superhydrophobic PFA/SiO 2 hybrid coating was successfully fabricated on the slide glass by spraying the mixture of PFA emulsion and hydrophobic SiO 2 particles using ethanol as cosolvent. The PFA emulsion was characterized by Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), water contact angle (WCA), transmission electron microscopy (TEM), and the effects of SiO 2 content on the wetting behavior and surface morphology of PFA/SiO 2 hybrid coating were investigated. To evaluate the stability of the hybrid coating, the acid and base resistance, weatherability and thermal stability were also studied. Results showed that the obtained PFA latex exhibited a core–shell structure with a particle size of 134.1 nm and a narrow polydispersity of 0.03. With the increase of dodecafluoroheptyl methacrylate (DFMA) content in the latex shell from 0 wt% to 31.8 wt%, the WCA of the PFA film enlarged from 85° to 104°, indicating that the introduction of fluorinated monomer was effective in reducing the surface energy. By adding different amount of SiO 2 particles, the surface morphology and wetting behavior of the PFA/SiO 2 hybrid coatings could be controlled. When the mass ratio of SiO 2 to PFA emulsion was 0.2, the surface roughness (Rq) increased to 173.6 nm and the wetting behavior of the surface became superhydrophobic with a WCA of 153°, resulted from the corporation of low surface energy and the binary nano/microstructure on the surface. The as-prepared PFA

  5. Cytocompatible and water stable ultrafine protein fibers for tissue engineering

    Science.gov (United States)

    Jiang, Qiuran

    This dissertation proposal focuses on the development of cytocompatible and water stable protein ultrafine fibers for tissue engineering. The protein-based ultrafine fibers have the potential to be used for biomedicine, due to their biocompatibility, biodegradability, similarity to natural extracellular matrix (ECM) in physical structure and chemical composition, and superior adsorption properties due to their high surface to volume ratio. However, the current technologies to produce the protein-based ultrafine fibers for biomedical applications still have several problems. For instance, the current electrospinning and phase separation technologies generate scaffolds composed of densely compacted ultrafine fibers, and cells can spread just on the surface of the fiber bulk, and hardly penetrate into the inner sections of scaffolds. Thus, these scaffolds can merely emulate the ECM as a two dimensional basement membrane, but are difficult to mimic the three dimensional ECM stroma. Moreover, the protein-based ultrafine fibers do not possess sufficient water stability and strength for biomedical applications, and need modifications such as crosslinking. However, current crosslinking methods are either high in toxicity or low in crosslinking efficiency. To solve the problems mentioned above, zein, collagen, and gelatin were selected as the raw materials to represent plant proteins, animal proteins, and denatured proteins in this dissertation. A benign solvent system was developed specifically for the fabrication of collagen ultrafine fibers. In addition, the gelatin scaffolds with a loose fibrous structure, high cell-accessibility and cell viability were produced by a novel ultralow concentration phase separation method aiming to simulate the structure of three dimensional (3D) ECM stroma. Non-toxic crosslinking methods using citric acid as the crosslinker were also developed for electrospun or phase separated scaffolds from these three proteins, and proved to be

  6. Stable atomic hydrogen: Polarized atomic beam source

    International Nuclear Information System (INIS)

    Niinikoski, T.O.; Penttilae, S.; Rieubland, J.M.; Rijllart, A.

    1984-01-01

    We have carried out experiments with stable atomic hydrogen with a view to possible applications in polarized targets or polarized atomic beam sources. Recent results from the stabilization apparatus are described. The first stable atomic hydrogen beam source based on the microwave extraction method (which is being tested ) is presented. The effect of the stabilized hydrogen gas density on the properties of the source is discussed. (orig.)

  7. Electropolishing of Stainless Steel Implants for Stable Functional Osteosynthesis

    Directory of Open Access Journals (Sweden)

    Omel’chuk, A.О.

    2016-01-01

    Full Text Available A new method for the electropolishing stainless steel for stable functional osteosynthesis has been developed. The polishing of implants was carried out in solutions, based on the ternary system H2SO4—H3PO4—H2O with stepwise decreasing the current density and increasing the orthophosphoric acid concentration. The optimal polishing conditions (current density, solution composition, temperature and duration have been determined. The developed method improves the quality and mechanical properties of the surface.

  8. Towards effective and stable probiotics.

    Science.gov (United States)

    Yarullina, D R; Damshkaln, L G; Bruslik, N L; Konovalova, O A; Ilinskaya, O N; Lozinsky, V I

    2015-01-01

    months at 4°C. The bacterial viability tests also demonstrated that after 6 h treatment with 2% bile or HCl (pH 2) L. plantarum 8PA3 exhibited increased sensitivity (viability 14% and 0.4%, respectively). However, in similar conditions no significant differences were noticed between bacterial viability obtained for formulated with starch and non-formulated bacteria. Furthermore, we showed that loading into SPS had no effect on bacterial production of nitric oxide (NO) - a pluripotent regulatory molecule in human organism. Overall, the results strongly support that formulation with polymeric matrices on the basis of SPS represent an appealing technology of probiotics production. It provides slow release of bacteria in target environment and does not alter their viability and NO biosynthesis. However, SPS excipient does not preserve the bacteria from harsh conditions of upper GIT. Therefore, we conclude that for oral administration the composition should be loaded in acid-resistant capsules.

  9. Non-linear Yang-Mills instantons from strings are π-stable D-branes

    International Nuclear Information System (INIS)

    Enger, H.; Luetken, C.A.

    2004-01-01

    We show that B-type Π-stable D-branes do not in general reduce to the (Gieseker-) stable holomorphic vector bundles used in mathematics to construct moduli spaces. We show that solutions of the almost Hermitian Yang-Mills equations for the non-linear deformations of Yang-Mills instantons that appear in the low-energy geometric limit of strings exist iff they are π-stable, a geometric large volume version of Π-stability. This shows that π-stability is the correct physical stability concept. We speculate that this string-canonical choice of stable objects, which is encoded in and derived from the central charge of the string-algebra, should find applications to algebraic geometry where there is no canonical choice of stable geometrical objects

  10. Spitzenkorper, exocyst, and polarisome components in Candida albicans hyphae show different patterns of localization and have distinct dynamic properties.

    Science.gov (United States)

    Jones, Laura A; Sudbery, Peter E

    2010-10-01

    During the extreme polarized growth of fungal hyphae, secretory vesicles are thought to accumulate in a subapical region called the Spitzenkörper. The human fungal pathogen Candida albicans can grow in a budding yeast or hyphal form. When it grows as hyphae, Mlc1 accumulates in a subapical spot suggestive of a Spitzenkörper-like structure, while the polarisome components Spa2 and Bud6 localize to a surface crescent. Here we show that the vesicle-associated protein Sec4 also localizes to a spot, confirming that secretory vesicles accumulate in the putative C. albicans Spitzenkörper. In contrast, exocyst components localize to a surface crescent. Using a combination of fluorescence recovery after photobleaching (FRAP) and fluorescence loss in photobleaching (FLIP) experiments and cytochalasin A to disrupt actin cables, we showed that Spitzenkörper-located proteins are highly dynamic. In contrast, exocyst and polarisome components are stably located at the cell surface. It is thought that in Saccharomyces cerevisiae exocyst components are transported to the cell surface on secretory vesicles along actin cables. If each vesicle carried its own complement of exocyst components, then it would be expected that exocyst components would be as dynamic as Sec4 and would have the same pattern of localization. This is not what we observe in C. albicans. We propose a model in which a stream of vesicles arrives at the tip and accumulates in the Spitzenkörper before onward delivery to the plasma membrane mediated by exocyst and polarisome components that are more stable residents of the cell surface.

  11. STABLE CONIC-HELICAL ORBITS OF PLANETS AROUND BINARY STARS: ANALYTICAL RESULTS

    Energy Technology Data Exchange (ETDEWEB)

    Oks, E. [Physics Department, 206 Allison Lab., Auburn University, Auburn, AL 36849 (United States)

    2015-05-10

    Studies of planets in binary star systems are especially important because it was estimated that about half of binary stars are capable of supporting habitable terrestrial planets within stable orbital ranges. One-planet binary star systems (OBSS) have a limited analogy to objects studied in atomic/molecular physics: one-electron Rydberg quasimolecules (ORQ). Specifically, ORQ, consisting of two fully stripped ions of the nuclear charges Z and Z′ plus one highly excited electron, are encountered in various plasmas containing more than one kind of ion. Classical analytical studies of ORQ resulted in the discovery of classical stable electronic orbits with the shape of a helix on the surface of a cone. In the present paper we show that despite several important distinctions between OBSS and ORQ, it is possible for OBSS to have stable planetary orbits in the shape of a helix on a conical surface, whose axis of symmetry coincides with the interstellar axis; the stability is not affected by the rotation of the stars. Further, we demonstrate that the eccentricity of the stars’ orbits does not affect the stability of the helical planetary motion if the center of symmetry of the helix is relatively close to the star of the larger mass. We also show that if the center of symmetry of the conic-helical planetary orbit is relatively close to the star of the smaller mass, a sufficiently large eccentricity of stars’ orbits can switch the planetary motion to the unstable mode and the planet would escape the system. We demonstrate that such planets are transitable for the overwhelming majority of inclinations of plane of the stars’ orbits (i.e., the projections of the planet and the adjacent start on the plane of the sky coincide once in a while). This means that conic-helical planetary orbits at binary stars can be detected photometrically. We consider, as an example, Kepler-16 binary stars to provide illustrative numerical data on the possible parameters and the

  12. Local Search Approaches in Stable Matching Problems

    Directory of Open Access Journals (Sweden)

    Toby Walsh

    2013-10-01

    Full Text Available The stable marriage (SM problem has a wide variety of practical applications, ranging from matching resident doctors to hospitals, to matching students to schools or, more generally, to any two-sided market. In the classical formulation, n men and n women express their preferences (via a strict total order over the members of the other sex. Solving an SM problem means finding a stable marriage where stability is an envy-free notion: no man and woman who are not married to each other would both prefer each other to their partners or to being single. We consider both the classical stable marriage problem and one of its useful variations (denoted SMTI (Stable Marriage with Ties and Incomplete lists where the men and women express their preferences in the form of an incomplete preference list with ties over a subset of the members of the other sex. Matchings are permitted only with people who appear in these preference lists, and we try to find a stable matching that marries as many people as possible. Whilst the SM problem is polynomial to solve, the SMTI problem is NP-hard. We propose to tackle both problems via a local search approach, which exploits properties of the problems to reduce the size of the neighborhood and to make local moves efficiently. We empirically evaluate our algorithm for SM problems by measuring its runtime behavior and its ability to sample the lattice of all possible stable marriages. We evaluate our algorithm for SMTI problems in terms of both its runtime behavior and its ability to find a maximum cardinality stable marriage. Experimental results suggest that for SM problems, the number of steps of our algorithm grows only as O(n log(n, and that it samples very well the set of all stable marriages. It is thus a fair and efficient approach to generate stable marriages. Furthermore, our approach for SMTI problems is able to solve large problems, quickly returning stable matchings of large and often optimal size, despite the

  13. Statistical optimization of thermo-alkali stable xylanase production from Bacillus tequilensis strain ARMATI

    Directory of Open Access Journals (Sweden)

    Ameer Khusro

    2016-07-01

    Conclusions: The cellulase-free xylanase showed an alkali-tolerant and thermo-stable property with potentially applicable nature at industrial scale. This statistical approach established a major contribution in enzyme production from the isolate by optimizing independent factors and represents a first reference on the enhanced production of thermo-alkali stable cellulase-free xylanase from B. tequilensis.

  14. Facile and green synthesis of highly stable L-cysteine functionalized copper nanoparticles

    International Nuclear Information System (INIS)

    Kumar, Nikhil; Upadhyay, Lata Sheo Bachan

    2016-01-01

    Highlights: • A facile and eco-friendly method for the synthesis of L-cysteine functionalized copper nanoparticles is reported. • Synthesis of Highly stable L-cysteine functionalized copper nanoparticles (∼40 nm) was done in an aqueous medium. • FTIR analysis shows that L-cysteine bound to the nanoparticle surface via thiol group. - Abstract: A simple eco-friendly method for L-cysteine capped copper nanoparticles (CCNPs) synthesis in aqueous solution has been developed. Glucose and L-cysteine were used as reducing agent and capping/functionalizing agent, respectively. Different parameters such as capping agent concentration, pH, reaction temperature, and reducing agent concentration were optimized during the synthesis. The L-cysteine capped copper nanoparticle were characterized by ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, Particle size and zeta potential analyser, and high resolution transmission electron microscopy. Spherical shaped cysteine functionalized/capped copper nanoparticles with an average size of 40 nm were found to be highly stable at room temperature (RT) for a period of 1 month

  15. Facile and green synthesis of highly stable L-cysteine functionalized copper nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Nikhil, E-mail: nkumar.phd2011.bt@nitrr.ac.in; Upadhyay, Lata Sheo Bachan, E-mail: contactlataupadhyay@gmail.com

    2016-11-01

    Highlights: • A facile and eco-friendly method for the synthesis of L-cysteine functionalized copper nanoparticles is reported. • Synthesis of Highly stable L-cysteine functionalized copper nanoparticles (∼40 nm) was done in an aqueous medium. • FTIR analysis shows that L-cysteine bound to the nanoparticle surface via thiol group. - Abstract: A simple eco-friendly method for L-cysteine capped copper nanoparticles (CCNPs) synthesis in aqueous solution has been developed. Glucose and L-cysteine were used as reducing agent and capping/functionalizing agent, respectively. Different parameters such as capping agent concentration, pH, reaction temperature, and reducing agent concentration were optimized during the synthesis. The L-cysteine capped copper nanoparticle were characterized by ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, Particle size and zeta potential analyser, and high resolution transmission electron microscopy. Spherical shaped cysteine functionalized/capped copper nanoparticles with an average size of 40 nm were found to be highly stable at room temperature (RT) for a period of 1 month.

  16. Relevant signs of stable and unstable thoracolumbar vertebral column trauma

    International Nuclear Information System (INIS)

    Gehweiler, J.A.; Daffner, R.H.; Osborne, R.L.

    1981-01-01

    One-hundred and seventeen patients with acute thoracolumbar vertebral column fracture or fracture-dislocations were analyzed and classified into stable (36%) and unstable (64%). Eight helpful roentgen signs were observed that may serve to direct attention to serious underlying, often occult, fractures and dislocations. The changes fall into four principal groups: abnormal soft tissues, abnormal vertebral alignment, abnormal joints, and widened vertebral canal. All stable and unstable lesions showed abnormal soft tissues, while 70% demonstrated kyphosis and/or scoliosis, and an abnormal adjacent intervertebral disk space. All unstable lesions showed one or more of the following signs: displaced vertebra, widened interspinous space, abnormal apophyseal joint(s), and widened vertebral canal. (orig.)

  17. UV Photography Shows Hidden Sun Damage

    Science.gov (United States)

    ... mcat1=de12", ]; for (var c = 0; c UV photography shows hidden sun damage A UV photograph gives ... developing skin cancer and prematurely aged skin. Normal photography UV photography 18 months of age: This boy's ...

  18. Soluble and stable zethrenebis(dicarboximide) and its quinone

    KAUST Repository

    Sun, Zhe

    2010-10-15

    Soluble and stable zethrenebis(dicarboximide) (1) was synthesized by an in situ Stille cross coupling/transannular cyclization reaction. 1 showed largely improved photostability and solubility compared with the very unstable zethrene and it also exhibited far-red absorption and emission with high photoluminescence quantum yield. Bromination of 1 with NBS/DMF gave its quinone form 2 via an unusual pathway. © 2010 American Chemical Society.

  19. Radionuclide bone image in growing and stable bone island

    International Nuclear Information System (INIS)

    Go, R.T.; El-Khoury, G.Y.; Iowa Univ., Iowa City; Wehbe, M.A.

    1980-01-01

    A normal radionuclide bone image can facilitate distinction between a bone island and significant pathologic processes, especially an osteoblastic metastasis. This distinction becomes more crucial when growth is detected in an isolated sclerotic bone lesion or if a relatively large sclerotic lesion is detected de novo in patients with a known neoplasm. This report presents three patients with isolated bone islands: two with interval growth, the other with a relatively large stable lesion; all showing a normal radionuclide bone image. (orig.) [de

  20. Stochastic systems driven by alpha-stable noises

    DEFF Research Database (Denmark)

    Ditlevsen, Ove Dalager; Ditlevsen, P.

    1998-01-01

    with observed data. In particular the tailsof the observed response distributions may even for linear systems be more fat than the tails obtained for Gaussianwhite noise input. Also the excitation may show jumps that cannot be modeled by Gaussian white noise. The paper supports the possibility of using...... the larger class of so-calledalpha-stable white noises to provide a better fit. A geophysical application concerning ice age climate variations is described....

  1. Highly Stable and Active Catalyst for Sabatier Reactions

    Science.gov (United States)

    Hu, Jianli; Brooks, Kriston P.

    2012-01-01

    Highly active Ru/TiO2 catalysts for Sabatier reaction have been developed. The catalysts have shown to be stable under repeated shutting down/startup conditions. When the Ru/TiO2 catalyst is coated on the engineered substrate Fe-CrAlY felt, activity enhancement is more than doubled when compared with an identically prepared engineered catalyst made from commercial Degussa catalyst. Also, bimetallic Ru-Rh/TiO2 catalysts show high activity at high throughput.

  2. Stable black strings in anti-de sitter space

    International Nuclear Information System (INIS)

    Hirayama, Takayuki

    2002-01-01

    In my talk I show a black string which is a foliation of anti-de Sitter (AdS) Schwarzschild black hole becomes classically stable if the size of black hole horizon is larger than the AdS radius even if the black string extends infinitely. I will also give a comment on the relation with the Gubser-Mitra conjecture. This talk is based on our paper (Phys. Rev. D64: 064010, 2001) which is a collaboration with Gungwon Kang

  3. Searching for stable orbits in the HD 10180 planetary system

    Directory of Open Access Journals (Sweden)

    Laskar J.

    2011-02-01

    Full Text Available A planetary system with at least seven planets has been found around the star HD 10180. However, the traditional Keplerian and n-body fits to the data provide an orbital solution that becomes unstable very quickly, which may quest the reliability of the observations. Here we show that stable orbital configurations can be obtained if general relativity and long-term dissipation raised by tides on the innermost planet are taken into account.

  4. On the Hitting Probability of Max-Stable Processes

    OpenAIRE

    Hofmann, Martin

    2012-01-01

    The probability that a max-stable process {\\eta} in C[0, 1] with identical marginal distribution function F hits x \\in R with 0 < F (x) < 1 is the hitting probability of x. We show that the hitting probability is always positive, unless the components of {\\eta} are completely dependent. Moreover, we consider the event that the paths of standard MSP hit some x \\in R twice and we give a sufficient condition for a positive probability of this event.

  5. The Fractional Poisson Process and the Inverse Stable Subordinator

    OpenAIRE

    Meerschaert, Mark; Nane, Erkan; Vellaisamy, P.

    2011-01-01

    The fractional Poisson process is a renewal process with Mittag-Leffler waiting times. Its distributions solve a time-fractional analogue of the Kolmogorov forward equation for a Poisson process. This paper shows that a traditional Poisson process, with the time variable replaced by an independent inverse stable subordinator, is also a fractional Poisson process. This result unifies the two main approaches in the stochastic theory of time-fractional diffusion equations. The equivalence extend...

  6. Exotic Paired States with Anisotropic Spin-Dependent Fermi Surfaces

    International Nuclear Information System (INIS)

    Feiguin, Adrian E.; Fisher, Matthew P. A.

    2009-01-01

    We propose a model for realizing exotic paired states in cold Fermi gases by using a spin-dependent optical lattice to engineer mismatched Fermi surfaces for each hyperfine species. The BCS phase diagram shows a stable paired superfluid state with coexisting pockets of momentum space with gapless unpaired carriers, similar to the Sarma state in polarized mixtures, but in our case the system is unpolarized. We propose the possible existence of an exotic 'Cooper-pair Bose-metal' phase, which has a gap for single fermion excitations but gapless and uncondensed 'Cooper-pair' excitations residing on a 'Bose surface' in momentum space.

  7. Nitrogen Fate in a Phreatic Fluviokarst Watershed: a Stable Isotope, Sediment Tracing, and Numerical Modeling Approach

    Science.gov (United States)

    Husic, A.; Fox, J.; Ford, W. I., III; Agouridis, C.; Currens, J. C.; Taylor, C. J.

    2017-12-01

    Sediment tracing tools provide an insight into provenance, fate, and transport of sediment and, when coupled to stable isotopes, can elucidate in-stream biogeochemical processes. Particulate nitrogen fate in fluviokarst systems is a relatively unexplored area of research partially due to the complex hydrodynamics at play in karst systems. Karst topography includes turbulent conduits that transport groundwater and contaminants at speeds more typical of open channel flows than laminar Darcian flows. While it is accepted that karst hydro-geomorphology represents a hybrid surface-subsurface system for fluid, further investigation is needed to determine whether, and to what extent, karst systems behave like surface agricultural streams or porous media aquifers with respect to their role in nitrogen cycling. Our objective is to gain an understanding of in-conduit nitrogen processes and their effect on net nitrogen-exports from karst springs to larger waterbodies. The authors apply water, sediment, carbon, and nitrogen tracing techniques to analyze water for nitrate, sediment carbon and nitrogen, and stable sediment nitrogen isotope (δ15N). Thereafter, a new numerical model is formulated that: simulates dissolved inorganic nitrogen and sediment nitrogen transformations in the phreatic karst conduit; couples carbon turnover and nitrogen transformations in the model structure; and simulates the nitrogen stable isotope mass balance for the dissolved and sediment phases. Nitrogen tracing data results show a significant increase in δ15N of sediment nitrogen at the spring outlet relative to karst inputs indicating the potential for isotope fractionation during dissolved N uptake by bed sediments in the conduit and during denitrification within bed sediments. The new numerical modeling structure is then used to reproduce the data results and provide an estimate of the relative dominance of N uptake and denitrification within the surficial sediments of the karst conduit system

  8. The free radical process for the polymer surface treated by radio frequency plasma

    International Nuclear Information System (INIS)

    Ma Yuguang; Yang Meiling; Shen Jiacong; Zheng Yingguang

    1992-01-01

    The formation and translation of the free radicals on the polymer surface treated by plasmas were studied and observed by ESR measurement. The results show that C-C bond split was main reaction in the process of the polymer irradiated by plasma, by which a stable alkyl free radical was formed. When alkyl free radical contacted with air, they translate into peroxide radical instantaneously. The peroxide radical was not as stable as radical in vacuum, they can react each other to form some polar-groups on polymer surface. The interaction between the peroxide free radical and polymer chain was correlative not only to the structure of polymer but also to the molecular motion of the polymer chain. The nature of plasma treating polymer surface was that the peroxide radicals were led onto polymer surface

  9. Educational Outreach: The Space Science Road Show

    Science.gov (United States)

    Cox, N. L. J.

    2002-01-01

    The poster presented will give an overview of a study towards a "Space Road Show". The topic of this show is space science. The target group is adolescents, aged 12 to 15, at Dutch high schools. The show and its accompanying experiments would be supported with suitable educational material. Science teachers at schools can decide for themselves if they want to use this material in advance, afterwards or not at all. The aims of this outreach effort are: to motivate students for space science and engineering, to help them understand the importance of (space) research, to give them a positive feeling about the possibilities offered by space and in the process give them useful knowledge on space basics. The show revolves around three main themes: applications, science and society. First the students will get some historical background on the importance of space/astronomy to civilization. Secondly they will learn more about novel uses of space. On the one hand they will learn of "Views on Earth" involving technologies like Remote Sensing (or Spying), Communication, Broadcasting, GPS and Telemedicine. On the other hand they will experience "Views on Space" illustrated by past, present and future space research missions, like the space exploration missions (Cassini/Huygens, Mars Express and Rosetta) and the astronomy missions (Soho and XMM). Meanwhile, the students will learn more about the technology of launchers and satellites needed to accomplish these space missions. Throughout the show and especially towards the end attention will be paid to the third theme "Why go to space"? Other reasons for people to get into space will be explored. An important question in this is the commercial (manned) exploration of space. Thus, the questions of benefit of space to society are integrated in the entire show. It raises some fundamental questions about the effects of space travel on our environment, poverty and other moral issues. The show attempts to connect scientific with

  10. Colloidal graphite/graphene nanostructures using collagen showing enhanced thermal conductivity

    Science.gov (United States)

    Bhattacharya, Soumya; Dhar, Purbarun; Das, Sarit K; Ganguly, Ranjan; Webster, Thomas J; Nayar, Suprabha

    2014-01-01

    In the present study, the exfoliation of natural graphite (GR) directly to colloidal GR/graphene (G) nanostructures using collagen (CL) was studied as a safe and scalable process, akin to numerous natural processes and hence can be termed “biomimetic”. Although the exfoliation and functionalization takes place in just 1 day, it takes about 7 days for the nano GR/G flakes to stabilize. The predominantly aromatic residues of the triple helical CL forms its own special micro and nanoarchitecture in acetic acid dispersions. This, with the help of hydrophobic and electrostatic forces, interacts with GR and breaks it down to nanostructures, forming a stable colloidal dispersion. Surface enhanced Raman spectroscopy, X-ray diffraction, photoluminescence, fluorescence, and X-ray photoelectron spectroscopy of the colloid show the interaction between GR and CL on day 1 and 7. Differential interference contrast images in the liquid state clearly reveal how the GR flakes are entrapped in the CL fibrils, with a corresponding fluorescence image showing the intercalation of CL within GR. Atomic force microscopy of graphene-collagen coated on glass substrates shows an average flake size of 350 nm, and the hexagonal diffraction pattern and thickness contours of the G flakes from transmission electron microscopy confirm ≤ five layers of G. Thermal conductivity of the colloid shows an approximate 17% enhancement for a volume fraction of less than approximately 0.00005 of G. Thus, through the use of CL, this new material and process may improve the use of G in terms of biocompatibility for numerous medical applications that currently employ G, such as internally controlled drug-delivery assisted thermal ablation of carcinoma cells. PMID:24648728

  11. Colloidal graphite/graphene nanostructures using collagen showing enhanced thermal conductivity.

    Science.gov (United States)

    Bhattacharya, Soumya; Dhar, Purbarun; Das, Sarit K; Ganguly, Ranjan; Webster, Thomas J; Nayar, Suprabha

    2014-01-01

    In the present study, the exfoliation of natural graphite (GR) directly to colloidal GR/graphene (G) nanostructures using collagen (CL) was studied as a safe and scalable process, akin to numerous natural processes and hence can be termed "biomimetic". Although the exfoliation and functionalization takes place in just 1 day, it takes about 7 days for the nano GR/G flakes to stabilize. The predominantly aromatic residues of the triple helical CL forms its own special micro and nanoarchitecture in acetic acid dispersions. This, with the help of hydrophobic and electrostatic forces, interacts with GR and breaks it down to nanostructures, forming a stable colloidal dispersion. Surface enhanced Raman spectroscopy, X-ray diffraction, photoluminescence, fluorescence, and X-ray photoelectron spectroscopy of the colloid show the interaction between GR and CL on day 1 and 7. Differential interference contrast images in the liquid state clearly reveal how the GR flakes are entrapped in the CL fibrils, with a corresponding fluorescence image showing the intercalation of CL within GR. Atomic force microscopy of graphene-collagen coated on glass substrates shows an average flake size of 350 nm, and the hexagonal diffraction pattern and thickness contours of the G flakes from transmission electron microscopy confirm ≤ five layers of G. Thermal conductivity of the colloid shows an approximate 17% enhancement for a volume fraction of less than approximately 0.00005 of G. Thus, through the use of CL, this new material and process may improve the use of G in terms of biocompatibility for numerous medical applications that currently employ G, such as internally controlled drug-delivery assisted thermal ablation of carcinoma cells.

  12. Metabolic studies in man using stable isotopes

    International Nuclear Information System (INIS)

    Faust, H.; Jung, K.; Krumbiegel, P.

    1993-01-01

    In this project, stable isotope compounds and stable isotope pharmaceuticals were used (with emphasis on the application of 15 N) to study several aspects of nitrogen metabolism in man. Of the many methods available, the 15 N stable isotope tracer technique holds a special position because the methodology for application and nitrogen isotope analysis is proven and reliable. Valid routine methods using 15 N analysis by emission spectrometry have been demonstrated. Several methods for the preparation of biological material were developed during our participation in the Coordinated Research Programme. In these studies, direct procedures (i.e. use of diluted urine as a samples without chemical preparation) or rapid isolation methods were favoured. Within the scope of the Analytical Quality Control Service (AQCS) enriched stable isotope reference materials for medical and biological studies were prepared and are now available through the International Atomic Energy Agency. The materials are of special importance as the increasing application of stable isotopes as tracers in medical, biological and agricultural studies has focused interest on reliable measurements of biological material of different origin. 24 refs

  13. 1-Dodecanethiol based highly stable self-assembled monolayers for germanium passivation

    International Nuclear Information System (INIS)

    Cai, Qi; Xu, Baojian; Ye, Lin; Di, Zengfeng; Huang, Shanluo; Du, Xiaowei; Zhang, Jishen; Jin, Qinghui; Zhao, Jianlong

    2015-01-01

    Highlights: • A simple and effective approach for higly stable germanium passivation. • 1-Dodecanethiol self-assembled monolayers for germanium oxidation resistance. • The influence factors of germanium passivation were systematically studied. • The stability of the passivated Ge was more than 10 days even in water conditions. - Abstract: As a typical semiconductor material, germanium has the potential to replace silicon for future-generation microelectronics, due to its better electrical properties. However, the lack of stable surface state has limited its extensive use for several decades. In this work, we demonstrated highly stable self-assembled monolayers (SAMs) on Ge surface to prevent oxidization for further applications. After the pretreatment in hydrochloric acid, the oxide-free and Cl-terminated Ge could be further coated with 1-dodecanethiol (NDM) SAMs. The influence factors including reaction time, solvent component and reaction temperature were optimized to obtain stable passivated monolayer for oxidation resistance. Contact angle analysis, atomic force microscopy, ellipsometer and X-ray photoelectron spectroscopy were performed to characterize the functionalized Ge surface respectively. Meanwhile, the reaction mechanism and stability of thiols SAMs on Ge (1 1 1) surface were investigated. Finally, highly stable passivated NDM SAMs on Ge surface could be formed through immersing oxide-free Ge in mixture solvent (water/ethanol, v/v = 1:1) at appropriately elevated temperature (∼80 °C) for 24 h. And the corresponding optimized passivated Ge surface was stable for more than 10 days even in water condition, which was much longer than the data reported and paved the way for the future practical applications of Ge.

  14. 1-Dodecanethiol based highly stable self-assembled monolayers for germanium passivation

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Qi [State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, No. 865, Changning Road, Shanghai 200050 (China); University of Chinese Academy of Sciences, No. 19A, Yuquan Road, Beijing 100049 (China); Xu, Baojian, E-mail: xbj@mail.sim.ac.cn [State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, No. 865, Changning Road, Shanghai 200050 (China); Shanghai Internet of Things Co., LTD, No. 1455, Pingcheng Road, Shanghai 201899 (China); Ye, Lin [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, No. 865, Changning Road, Shanghai 200050 (China); University of Chinese Academy of Sciences, No. 19A, Yuquan Road, Beijing 100049 (China); Di, Zengfeng [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, No. 865, Changning Road, Shanghai 200050 (China); Huang, Shanluo; Du, Xiaowei [State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, No. 865, Changning Road, Shanghai 200050 (China); University of Chinese Academy of Sciences, No. 19A, Yuquan Road, Beijing 100049 (China); Zhang, Jishen; Jin, Qinghui [State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, No. 865, Changning Road, Shanghai 200050 (China); Zhao, Jianlong, E-mail: jlzhao@mail.sim.ac.cn [State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, No. 865, Changning Road, Shanghai 200050 (China)

    2015-10-30

    Highlights: • A simple and effective approach for higly stable germanium passivation. • 1-Dodecanethiol self-assembled monolayers for germanium oxidation resistance. • The influence factors of germanium passivation were systematically studied. • The stability of the passivated Ge was more than 10 days even in water conditions. - Abstract: As a typical semiconductor material, germanium has the potential to replace silicon for future-generation microelectronics, due to its better electrical properties. However, the lack of stable surface state has limited its extensive use for several decades. In this work, we demonstrated highly stable self-assembled monolayers (SAMs) on Ge surface to prevent oxidization for further applications. After the pretreatment in hydrochloric acid, the oxide-free and Cl-terminated Ge could be further coated with 1-dodecanethiol (NDM) SAMs. The influence factors including reaction time, solvent component and reaction temperature were optimized to obtain stable passivated monolayer for oxidation resistance. Contact angle analysis, atomic force microscopy, ellipsometer and X-ray photoelectron spectroscopy were performed to characterize the functionalized Ge surface respectively. Meanwhile, the reaction mechanism and stability of thiols SAMs on Ge (1 1 1) surface were investigated. Finally, highly stable passivated NDM SAMs on Ge surface could be formed through immersing oxide-free Ge in mixture solvent (water/ethanol, v/v = 1:1) at appropriately elevated temperature (∼80 °C) for 24 h. And the corresponding optimized passivated Ge surface was stable for more than 10 days even in water condition, which was much longer than the data reported and paved the way for the future practical applications of Ge.

  15. 2008 LHC Open Days Physics: the show

    CERN Multimedia

    2008-01-01

    A host of events and activities await visitors to the LHC Open Days on 5 and 6 April. A highlight will be the physics shows funded by the European Physical Society (EPS), which are set to surprise and challenge children and adults alike! School children use their experience of riding a bicycle to understand how planets move around the sun (Copyright : Circus Naturally) Participating in the Circus Naturally show could leave a strange taste in your mouth! (Copyright : Circus Naturally) The Rino Foundation’s experiments with liquid nitrogen can be pretty exciting! (Copyright: The Rino Foundation)What does a bicycle have in common with the solar system? Have you ever tried to weigh air or visualise sound? Ever heard of a vacuum bazooka? If you want to discover the answers to these questions and more then come to the Physics Shows taking place at the CERN O...

  16. Online Italian fandoms of American TV shows

    Directory of Open Access Journals (Sweden)

    Eleonora Benecchi

    2015-06-01

    Full Text Available The Internet has changed media fandom in two main ways: it helps fans connect with each other despite physical distance, leading to the formation of international fan communities; and it helps fans connect with the creators of the TV show, deepening the relationship between TV producers and international fandoms. To assess whether Italian fan communities active online are indeed part of transnational online communities and whether the Internet has actually altered their relationship with the creators of the original text they are devoted to, qualitative analysis and narrative interviews of 26 Italian fans of American TV shows were conducted to explore the fan-producer relationship. Results indicated that the online Italian fans surveyed preferred to stay local, rather than using geography-leveling online tools. Further, the sampled Italian fans' relationships with the show runners were mediated or even absent.

  17. Patterns in Stable Isotope Values of Nitrogen and Carbon in ...

    Science.gov (United States)

    Stable isotope measurements of nitrogen and carbon (15N, 13ddC) are often used to characterize estuarine, nearshore, and open ocean ecosystems. Reliable information about the spatial distribution of base-level stable isotope values, often represented by primary producers, is critical to interpreting values in these ecosystems. While base-level isotope data are generally readily available for estuaries, nearshore coastal waters, and the open ocean, the continental shelf is less studied. To address this, and as a first step toward developing a surrogate for base-level isotopic signature in this region, we collected surface and deep water samples from the United States’ eastern continental shelf in the Western Atlantic Ocean, from the Gulf of Maine to Cape Hatteras, periodically between 2000 and 2013. During the study, particulate matter 15dN values ranged from 0.8 to 17.4‰, and 13dC values from −26.4 to −15.6‰over the region. We used spatial autocorrelation analysis and random forest modeling to examine the spatial trends and potential environmental drivers of the stable isotope values. We observed general trends toward lower values for both nitrogen and carbon isotopes at the seaward edge of the shelf. Conversely, higher 15dN and 13dC values were observed on the landward edge of the shelf, in particular in the southern portion of the sampling area. Across all sites, the magnitude of the difference between the 15dN of subsurface and surface particulate m

  18. Stable isotope composition of human fingernails from Slovakia

    International Nuclear Information System (INIS)

    Grolmusová, Zuzana; Rapčanová, Anna; Michalko, Juraj; Čech, Peter; Veis, Pavel

    2014-01-01

    Stable isotope composition of human fingernails has proven to be useful for documenting human dietary information and geographical patterns in archeological, forensic, anthropological and biological studies. Therefore, it is of interest to detect all factors influencing the stable isotopic composition in the certain regions in the world. Carbon and nitrogen isotope data of human fingernail keratin from 52 individuals from Slovakia were reported in this study. The online combustion and continuous flow isotope-ratio mass spectrometer Delta V Advantage was used for δ 13 C and δ 15 N analysis of fingernail keratin samples from 24 vegetarian and 28 omnivorous individuals. A group of people with frequent meat consumption showed enrichment in 13 C and 15 N isotopes in fingernails. A similar trend was observed with increasing seafood in an individual's diet. Moreover a significant difference was revealed between smokers and nonsmokers for both δ 13 C and δ 15 N values. These data were compared to previously published δ 13 C and δ 15 N fingernail values from across the globe. This study brings new information on the stable isotope signature of individuals from Slovakia and characterizes the Central European region for the first time. The stable isotope composition of fingernails is influenced by the frequency of meat and seafood consumption as well as smoking. - Highlights: • This study deals with stable isotope analyses of fingernails from Slovak volunteers. • δ 13 C and δ 15 N values of vegetarian and omnivore fingernails were compared. • Influence of sex, diet and smoking was studied

  19. Stable isotope composition of human fingernails from Slovakia

    Energy Technology Data Exchange (ETDEWEB)

    Grolmusová, Zuzana, E-mail: zuzana.grolmusova@geology.sk [Comenius University in Bratislava, Faculty of Mathematics, Physics and Informatics, Department of Experimental Physics, Mlynská dolina F2, 842 48 Bratislava (Slovakia); State Geological Institute of Dionýz Štúr, Laboratory of Isotope Geology, Mlynská dolina 1, 817 04 Bratislava (Slovakia); Rapčanová, Anna [Comenius University in Bratislava, Faculty of Mathematics, Physics and Informatics, Department of Experimental Physics, Mlynská dolina F2, 842 48 Bratislava (Slovakia); Michalko, Juraj; Čech, Peter [State Geological Institute of Dionýz Štúr, Laboratory of Isotope Geology, Mlynská dolina 1, 817 04 Bratislava (Slovakia); Veis, Pavel [Comenius University in Bratislava, Faculty of Mathematics, Physics and Informatics, Department of Experimental Physics, Mlynská dolina F2, 842 48 Bratislava (Slovakia); State Geological Institute of Dionýz Štúr, Laboratory of Isotope Geology, Mlynská dolina 1, 817 04 Bratislava (Slovakia)

    2014-10-15

    Stable isotope composition of human fingernails has proven to be useful for documenting human dietary information and geographical patterns in archeological, forensic, anthropological and biological studies. Therefore, it is of interest to detect all factors influencing the stable isotopic composition in the certain regions in the world. Carbon and nitrogen isotope data of human fingernail keratin from 52 individuals from Slovakia were reported in this study. The online combustion and continuous flow isotope-ratio mass spectrometer Delta V Advantage was used for δ{sup 13}C and δ{sup 15}N analysis of fingernail keratin samples from 24 vegetarian and 28 omnivorous individuals. A group of people with frequent meat consumption showed enrichment in {sup 13}C and {sup 15}N isotopes in fingernails. A similar trend was observed with increasing seafood in an individual's diet. Moreover a significant difference was revealed between smokers and nonsmokers for both δ{sup 13}C and δ{sup 15}N values. These data were compared to previously published δ{sup 13}C and δ{sup 15}N fingernail values from across the globe. This study brings new information on the stable isotope signature of individuals from Slovakia and characterizes the Central European region for the first time. The stable isotope composition of fingernails is influenced by the frequency of meat and seafood consumption as well as smoking. - Highlights: • This study deals with stable isotope analyses of fingernails from Slovak volunteers. • δ{sup 13}C and δ{sup 15}N values of vegetarian and omnivore fingernails were compared. • Influence of sex, diet and smoking was studied.

  20. Duchenne muscular dystrophy models show their age

    OpenAIRE

    Chamberlain, Jeffrey S.

    2010-01-01

    The lack of appropriate animal models has hampered efforts to develop therapies for Duchenne muscular dystrophy (DMD). A new mouse model lacking both dystrophin and telomerase (Sacco et al., 2010) closely mimics the pathological progression of human DMD and shows that muscle stem cell activity is a key determinant of disease severity.

  1. Show Them You Really Want the Job

    Science.gov (United States)

    Perlmutter, David D.

    2012-01-01

    Showing that one really "wants" the job entails more than just really wanting the job. An interview is part Broadway casting call, part intellectual dating game, part personality test, and part, well, job interview. When there are 300 applicants for a position, many of them will "fit" the required (and even the preferred) skills listed in the job…

  2. A Talk Show from the Past.

    Science.gov (United States)

    Gallagher, Arlene F.

    1991-01-01

    Describes a two-day activity in which elementary students examine voting rights, the right to assemble, and women's suffrage. Explains the game, "Assemble, Reassemble," and a student-produced talk show with five students playing the roles of leaders of the women's suffrage movement. Profiles Elizabeth Cady Stanton, Lucretia Mott, Susan…

  3. Laser entertainment and light shows in education

    Science.gov (United States)

    Sabaratnam, Andrew T.; Symons, Charles

    2002-05-01

    Laser shows and beam effects have been a source of entertainment since its first public performance May 9, 1969, at Mills College in Oakland, California. Since 1997, the Photonics Center, NgeeAnn Polytechnic, Singapore, has been using laser shows as a teaching tool. Students are able to exhibit their creative skills and learn at the same time how lasers are used in the entertainment industry. Students will acquire a number of skills including handling three- phase power supply, operation of cooling system, and laser alignment. Students also acquire an appreciation of the arts, learning about shapes and contours as they develop graphics for the shows. After holography, laser show animation provides a combination of the arts and technology. This paper aims to briefly describe how a krypton-argon laser, galvanometer scanners, a polychromatic acousto-optic modulator and related electronics are put together to develop a laser projector. The paper also describes how students are trained to make their own laser animation and beam effects with music, and at the same time have an appreciation of the operation of a Class IV laser and the handling of optical components.

  4. The Last Great American Picture Show

    NARCIS (Netherlands)

    Elsaesser, Thomas; King, Noel; Horwath, Alexander

    2004-01-01

    The Last Great American Picture Show brings together essays by scholars and writers who chart the changing evaluations of the American cinema of the 1970s, sometimes referred to as the decade of the lost generation, but now more and more recognized as the first New Hollywood, without which the

  5. Chin Shan analyses show advantages of whole pool multi-rack approach

    International Nuclear Information System (INIS)

    Singh, K.P.; Soler, A.I.

    1991-01-01

    Nuclear fuel storage racks are essentially thin-walled, cellular structures of prismatic cross-section. Although the details of design vary from one supplier to another, certain key physical attributes are common to all designs. For example, all racks feature square cells of sufficient opening size and height to enable insertion and withdrawal of the fuel assembly. The array of cells is positioned in a vertical orientation and is supported off the pool slab surface by four or more support legs. The spent fuel pool is filled with the individual fuel racks. The plenum created by the support legs is essential for proper cooling of the fuel assemblies stored in the rack, which relies on natural convective cooling to extract the heat emitted by the spent fuel. However, it has the insalutary effect of making it kinematically less stable. Regulatory authorities require careful and comprehensive analysis of the response of the racks under the seismic motions postulated for the pool slab. Results from whole pool multi-rack (WPMR) analyses at the Chin Shan and Oyster Creek nuclear plants point up the potential inadequacies of single rack 3D analyses, and show just how important it is to carry out WPMR simulations, despite their abstruseness and high cost. (author)

  6. Perspective: Highly stable vapor-deposited glasses

    Science.gov (United States)

    Ediger, M. D.

    2017-12-01

    This article describes recent progress in understanding highly stable glasses prepared by physical vapor deposition and provides perspective on further research directions for the field. For a given molecule, vapor-deposited glasses can have higher density and lower enthalpy than any glass that can be prepared by the more traditional route of cooling a liquid, and such glasses also exhibit greatly enhanced kinetic stability. Because vapor-deposited glasses can approach the bottom of the amorphous part of the potential energy landscape, they provide insights into the properties expected for the "ideal glass." Connections between vapor-deposited glasses, liquid-cooled glasses, and deeply supercooled liquids are explored. The generality of stable glass formation for organic molecules is discussed along with the prospects for stable glasses of other types of materials.

  7. Concentration of stable elements in food products

    International Nuclear Information System (INIS)

    Montford, M.A.; Shank, K.E.; Hendricks, C.; Oakes, T.W.

    1980-01-01

    Food samples were taken from commercial markets and analyzed for stable element content. The concentrations of most stable elements (Ag, Al, As, Au, Ba, Br, Ca, Ce, Cl, Co, Cr, Cs, Cu, Fe, Hf, I, K, La, Mg, Mn, Mo, Na, Rb, Sb, Sc, Se, Sr, Ta, Th, Ti, V, Zn, Zr) were determined using multiple-element neutron activation analysis, while the concentrations of other elements (Cd, Hg, Ni, Pb) were determined using atomic absorption. The relevance of the concentrations found are noted in relation to other literature values. An earlier study was extended to include the determination of the concentration of stable elements in home-grown products in the vicinity of the Oak Ridge National Laboratory. Comparisons between the commercial and local food-stuff values are discussed

  8. Stable Chimeras and Independently Synchronizable Clusters

    Science.gov (United States)

    Cho, Young Sul; Nishikawa, Takashi; Motter, Adilson E.

    2017-08-01

    Cluster synchronization is a phenomenon in which a network self-organizes into a pattern of synchronized sets. It has been shown that diverse patterns of stable cluster synchronization can be captured by symmetries of the network. Here, we establish a theoretical basis to divide an arbitrary pattern of symmetry clusters into independently synchronizable cluster sets, in which the synchronization stability of the individual clusters in each set is decoupled from that in all the other sets. Using this framework, we suggest a new approach to find permanently stable chimera states by capturing two or more symmetry clusters—at least one stable and one unstable—that compose the entire fully symmetric network.

  9. Direct transition from a stable equilibrium to quasiperiodicity in non-smooth systems

    DEFF Research Database (Denmark)

    Zhusubaliyev, Z.T.; Mosekilde, Erik

    2008-01-01

    The purpose of this Letter is to show how a border-collision bifurcation in a piecewise-smooth dynamical system can produce a direct transition from a stable equilibrium point to a two-dimensional invariant torus. Considering a system of nonautonomous differential equations describing the behavior...... of a power electronic DC/DC converter, we first determine the chart of dynamical modes and show that there is a region of parameter space in which the system has a single stable equilibrium point. Under variation of the parameters, this equilibrium may collide with a discontinuity boundary between two smooth...... regions in phase space. When this happens, one can observe a number of different bifurcation scenarios. One scenario is the continuous transformation of the stable equilibrium into a stable period-1 cycle. Another is the transformation of the stable equilibrium into an unstable period-1 cycle with complex...

  10. Structure and optical properties of water covered Cu(110) surfaces

    International Nuclear Information System (INIS)

    Baghbanpourasl, A.

    2014-01-01

    (110) surface due to surface relaxation is studied using elastooptic theory. The RAS of the most thermodynamically stable structures are calculated. The calculated spectra can be used as a reference for RAS experiments for determining the adsorbed structure. Calculations show that for all of these structures, RA spectra are sensitive to the water structures considered. In other words different adsorbed water structures have different RA spectra, which makes the structures distinguishable from each other. The origins of the peaks are studied in the band structure and it is observed that surface states are not quenched when water adsorbs in intact form. (author) [de

  11. The method of synthesizing of superhydrophobic surfaces by PECVD

    Science.gov (United States)

    Orazbayev, Sagi; Gabdullin, Maratbek; Ramazanov, Tlekkabul; Dosbolayev, Merlan; Zhunisbekov, Askar; Omirbekov, Dulat; Otarbay, Zhuldyz

    2018-03-01

    The aim of this work was to obtain superhydrophobic surfaces in a plasma medium. The experiment was carried out using the PECVD method in two different modes: constant and pulsing. The surface roughness was obtained by applying nanoparticles synthesized in plasma in a mixture of argon and methane. The resulting particles were deposited on the surface of silicon and glass materials. The contact angle increased linearly depending on the number of cycles, until it reached 160° at 150-160th cycles, after that the increase in cycles does not affect the contact angle, since the saturation process is in progress. Also the effect of the working gas composition on the hydrophobicity of the surface was studied. At low concentrations of methane (1%) only particles are synthesized in the working gas, and hydrophobicity is unstable, with an increase in methane concentration (7%) nanofilms are synthesized from nanoclusters, and surface hydrophobicity is relatively stable. In addition, a pulsing plasma mode was used to obtain superhydrophobic surfaces. The hydrophobicity of the sample showed that the strength of the nanofilm was stable in comparison with the sample obtained in the first mode, but the contact angle was lower. The obtained samples were examined using SEM, SPM, optical analysis, and their contact angles were determined.

  12. Stable isotope paleoaltimetry and the evolution of landscapes and life

    Science.gov (United States)

    Mulch, Andreas

    2016-01-01

    Reconstructing topography of our planet not only advances our knowledge of the geodynamic processes that shape the Earth's surface; equally important it adds a key element towards understanding long-term continental moisture transport, atmospheric circulation and the distribution of biomes and biodiversity. Stable isotope paleoaltimetry exploits systematic decreases in the oxygen (δ18O) or hydrogen (δD) isotopic composition of precipitation along a mountain front when the interaction of topography and advected moist air masses induces orographic precipitation. These changes in δ18O or δD can be recovered from the geologic record and recent geochemical and modeling advances allow a broad range of proxy materials to be evaluated. Over the last 10 yr stable isotope paleoaltimetry has witnessed rapidly expanding research activities and has produced a broad array of fascinating tectonic and geomorphologic studies many of which have concentrated on determining the elevation history of continental plateau regions. These single-site studies have greatly expanded what used to be very sparse global paleoaltimetric data. The challenge now lies in disentangling the surface uplift component from the impact of climate change on δ18O and δD in precipitation. The robustness of stable isotope paleoaltimetry can be enhanced when high-elevation δ18O or δD data are referenced against low-elevation sites that track climate-modulated sea level δ18O or δD of precipitation through time (' δ- δ approach'). Analysis of central Andean paleosols documents that differences in δ18O of soil carbonate between the Subandean foreland and the Bolivian Altiplano are small between 11 and 7 Ma but rise rapidly to ca. 2.9‰ after 7 Ma, corroborating the magnitude of late Miocene change in δ18O on the Altiplano. Future advances in stable isotope paleoaltimetry will greatly benefit from addressing four key challenges: (1) Identifying topographically-induced changes in atmospheric

  13. Faster and Simpler Approximation of Stable Matchings

    Directory of Open Access Journals (Sweden)

    Katarzyna Paluch

    2014-04-01

    Full Text Available We give a 3 2 -approximation algorithm for finding stable matchings that runs in O(m time. The previous most well-known algorithm, by McDermid, has the same approximation ratio but runs in O(n3/2m time, where n denotes the number of people andm is the total length of the preference lists in a given instance. In addition, the algorithm and the analysis are much simpler. We also give the extension of the algorithm for computing stable many-to-many matchings.

  14. Bordism, stable homotopy and adams spectral sequences

    CERN Document Server

    Kochman, Stanley O

    1996-01-01

    This book is a compilation of lecture notes that were prepared for the graduate course "Adams Spectral Sequences and Stable Homotopy Theory" given at The Fields Institute during the fall of 1995. The aim of this volume is to prepare students with a knowledge of elementary algebraic topology to study recent developments in stable homotopy theory, such as the nilpotence and periodicity theorems. Suitable as a text for an intermediate course in algebraic topology, this book provides a direct exposition of the basic concepts of bordism, characteristic classes, Adams spectral sequences, Brown-Peter

  15. Stable isotopes in Lithuanian bioarcheological material

    Science.gov (United States)

    Skipityte, Raminta; Jankauskas, Rimantas; Remeikis, Vidmantas

    2015-04-01

    Investigation of bioarcheological material of ancient human populations allows us to understand the subsistence behavior associated with various adaptations to the environment. Feeding habits are essential to the survival and growth of ancient populations. Stable isotope analysis is accepted tool in paleodiet (Schutkowski et al, 1999) and paleoenvironmental (Zernitskaya et al, 2014) studies. However, stable isotopes can be useful not only in investigating human feeding habits but also in describing social and cultural structure of the past populations (Le Huray and Schutkowski, 2005). Only few stable isotope investigations have been performed before in Lithuanian region suggesting a quite uniform diet between males and females and protein intake from freshwater fish and animal protein. Previously, stable isotope analysis has only been used to study a Stone Age population however, more recently studies have been conducted on Iron Age and Late medieval samples (Jacobs et al, 2009). Anyway, there was a need for more precise examination. Stable isotope analysis were performed on human bone collagen and apatite samples in this study. Data represented various ages (from 5-7th cent. to 18th cent.). Stable carbon and nitrogen isotope analysis on medieval populations indicated that individuals in studied sites in Lithuania were almost exclusively consuming C3 plants, C3 fed terrestrial animals, and some freshwater resources. Current investigation demonstrated social differences between elites and country people and is promising in paleodietary and daily life reconstruction. Acknowledgement I thank prof. dr. G. Grupe, Director of the Anthropological and Palaeoanatomical State Collection in Munich for providing the opportunity to work in her laboratory. The part of this work was funded by DAAD. Antanaitis-Jacobs, Indre, et al. "Diet in early Lithuanian prehistory and the new stable isotope evidence." Archaeologia Baltica 12 (2009): 12-30. Le Huray, Jonathan D., and Holger

  16. Unconditionally stable microwave Si-IMPATT amplifiers

    International Nuclear Information System (INIS)

    Seddik, M.M.

    1986-07-01

    The purpose of this investigation has been the development of an improved understanding of the design and analysis of microwave reflection amplifiers employing the negative resistance property of the IMPATT devices. Unconditionally stable amplifier circuit using a Silicon IMPATT diode is designed. The problems associated with the design procedures and the stability criterion are discussed. A computer program is developed to perform the computations. The stable characteristics of a reflection-type Si-IMPATT amplifier, such as gain, frequency and bandwidth are examined. It was found that at large signal drive levels, 7 dB gain with bandwidth of 800 MHz at 22,5 mA was obtained. (author)

  17. Toward tuning the surface functionalization of small ceria nanoparticles

    International Nuclear Information System (INIS)

    Huang, Xing; Wang, Binghui; Grulke, Eric A.; Beck, Matthew J.

    2014-01-01

    Understanding and controlling the performance of ceria nanoparticle (CNP) catalysts requires knowledge of the detailed structure and property of CNP surfaces and any attached functional groups. Here we report thermogravimetric analysis results showing that hydrothermally synthesized ∼30 nm CNPs are decorated with 12.9 hydroxyl groups per nm 2 of CNP surface. Quantum mechanical calculations of the density and distribution of bound surface groups imply a scaling relationship for surface group density that balances formal charges in the functionalized CNP system. Computational results for CNPs with only hydroxyl surface groups yield a predicted density of bound hydroxyl groups for ∼30 nm CNPs that is ∼33% higher than measured densities. Quantitative agreement between predicted and measured hydroxyl surface densities is achieved when calculations consider CNPs with both –OH and –O x surface groups. For this more general treatment of CNP surface functionalizations, quantum mechanical calculations predict a range of stable surface group configurations that depend on the chemical potentials of O and H, and demonstrate the potential to tune CNP surface functionalizations by varying temperature and/or partial pressures of O 2 and H 2 O

  18. Reality, ficción o show

    Directory of Open Access Journals (Sweden)

    Sandra Ruíz Moreno

    2002-01-01

    Full Text Available Para tener un punto de vista claro y objetivo frente a la polémica establecida en torno al programa “Protagonistas de novela” y la tendiente proliferación de los reality show en las parrillas de programación de la televisión colombiana, se realizó un análisis de texto y contenido de dicho programa, intentando definirlo desde sus posibilidades de realidad, ficción y show. Las unidades de análisis y el estudio de su tratamiento arrojaron un alto contenido que gira en torno a las emociones del ser humano relacionadas con la convivencia, tratadas a manera de show y con algunos aportes textuales de ficción, pero sin su elemento mediador básico, el actor, quitándole toda la posibilidad de tener un tratamiento con la profundidad, distancia y ética que requieren los temas de esta índole. El resultado es un formato que sólo busca altos índices de sintonía y que pertenece más a la denominada televisión “trash”, que a una búsqueda de realidad del hombre y mucho menos de sociedad.

  19. Fabrication and characterization of stable superhydrophobic fluorinated-polyacrylate/silica hybrid coating

    Science.gov (United States)

    Li, Kunquan; Zeng, Xingrong; Li, Hongqiang; Lai, Xuejun

    2014-04-01

    The core-shell fluorinated-polyacrylate (PFA) emulsion was synthesized through emulsion polymerization method and the superhydrophobic PFA/SiO2 hybrid coating was successfully fabricated on the slide glass by spraying the mixture of PFA emulsion and hydrophobic SiO2 particles using ethanol as cosolvent. The PFA emulsion was characterized by Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), water contact angle (WCA), transmission electron microscopy (TEM), and the effects of SiO2 content on the wetting behavior and surface morphology of PFA/SiO2 hybrid coating were investigated. To evaluate the stability of the hybrid coating, the acid and base resistance, weatherability and thermal stability were also studied. Results showed that the obtained PFA latex exhibited a core-shell structure with a particle size of 134.1 nm and a narrow polydispersity of 0.03. With the increase of dodecafluoroheptyl methacrylate (DFMA) content in the latex shell from 0 wt% to 31.8 wt%, the WCA of the PFA film enlarged from 85° to 104°, indicating that the introduction of fluorinated monomer was effective in reducing the surface energy. By adding different amount of SiO2 particles, the surface morphology and wetting behavior of the PFA/SiO2 hybrid coatings could be controlled. When the mass ratio of SiO2 to PFA emulsion was 0.2, the surface roughness (Rq) increased to 173.6 nm and the wetting behavior of the surface became superhydrophobic with a WCA of 153°, resulted from the corporation of low surface energy and the binary nano/microstructure on the surface. The as-prepared PFA/SiO2 hybrid coating showed good acid and base corrosion resistance, and it could keep superhydrophobicity after being heated at 250 °C for 2 h or exposed to ambient atmosphere for more than 3 months. Additionally, the superhydrophobic PFA/SiO2 hybrid coating could be applied to various substrates through spraying. This was a green and eco-friendly method in fabricating stable

  20. Extremal surface barriers

    International Nuclear Information System (INIS)

    Engelhardt, Netta; Wall, Aron C.

    2014-01-01

    We present a generic condition for Lorentzian manifolds to have a barrier that limits the reach of boundary-anchored extremal surfaces of arbitrary dimension. We show that any surface with nonpositive extrinsic curvature is a barrier, in the sense that extremal surfaces cannot be continuously deformed past it. Furthermore, the outermost barrier surface has nonnegative extrinsic curvature. Under certain conditions, we show that the existence of trapped surfaces implies a barrier, and conversely. In the context of AdS/CFT, these barriers imply that it is impossible to reconstruct the entire bulk using extremal surfaces. We comment on the implications for the firewall controversy

  1. Surface moisture estimation in urban areas

    Science.gov (United States)

    Jiang, Yitong

    ) model was used to estimate soil moisture and ET and fractional cover of urban landscape was used to estimate soil moisture and ET over vegetation, soil, and impervious surfaces. The results of this dissertation showed the general trend of daily and hourly soil moisture and ET over vegetation, soil, and impervious surfaces in summer, fall, and winter seasons, and the response of soil moisture and ET to precipitations over three types of land covers. In summer, hourly soil moisture fluctuates yet stable; during frequent precipitation, hourly ET over soil and impervious surface show similar patterns, while vegetation surfaces yielded lower ET, which indicated that the distribution and change of surface moisture is associated with the distribution and vigor of urban trees. From fall to winter, the general trend of soil moisture and ET were found decreased, and response to precipitations becomes weaker in winter. The spatial distribution of ET shows that the central urban area has higher ET than regular impervious surfaces and the city's average, which indicate the distribution of surface moisture is associated with the structural complexity of buildings. The two hypotheses were supported, and the methodology is tested to be effective in surface moisture estimation in urban areas. The results suggested future studies on the impact of anthropogenic heat on surface moisture and the data integrity issue in multiple data source in urban areas.

  2. Stable isotope records for the last 10 000 years from Okshola cave (Fauske, northern Norway and regional comparisons

    Directory of Open Access Journals (Sweden)

    H. Linge

    2009-11-01

    Full Text Available The sensitivity of terrestrial environments to past changes in heat transport is expected to be manifested in Holocene climate proxy records on millennial to seasonal timescales. Stalagmite formation in the Okshola cave near Fauske (northern Norway began at about 10.4 ka, soon after the valley was deglaciated. Past monitoring of the cave and surface has revealed stable modern conditions with uniform drip rates, relative humidity and temperature. Stable isotope records from two stalagmites provide time-series spanning from c. 10 380 yr to AD 1997; a banded, multi-coloured stalagmite (Oks82 was formed between 10 380 yr and 5050 yr, whereas a pristine, white stalagmite (FM3 covers the period from ~7500 yr to the present. The stable oxygen isotope (δ18Oc, stable carbon isotope (δ13Cc, and growth rate records are interpreted as showing i a negative correlation between cave/surface temperature and δ18Oc, ii a positive correlation between wetness and δ13Cc, and iii a positive correlation between temperature and growth rate. Following this, the data from Okshola show that the Holocene was characterised by high-variability climate in the early part, low-variability climate in the middle part, and high-variability climate and shifts between two distinct modes in the late part.

    A total of nine Scandinavian stalagmite δ18Oc records of comparable dating precision are now available for parts or most of the Holocene. None of them show a clear Holocene thermal optimum, suggesting that they are influenced by annual mean temperature (cave temperature rather than seasonal temperature. For the last 1000 years, δ18Oc values display a depletion-enrichment-depletion pattern commonly interpreted as reflecting the conventional view on climate development for the last millennium. Although the δ18

  3. A simple route to prepare stable hydroxyapatite nanoparticles suspension

    International Nuclear Information System (INIS)

    Han Yingchao; Wang Xinyu; Li Shipu

    2009-01-01

    A simple ultrasound assisted precipitation method with addition of glycosaminoglycans (GAGs) is proposed to prepare stable hydroxyapatite (HAP) nanoparticles suspension from the mixture of Ca(H 2 PO 4 ) 2 solution and Ca(OH) 2 solution. The product was characterized by XRD, FT-IR, TEM, HRTEM and particle size, and zeta potential analyzer. TEM observation shows that the suspension is composed of 10-20 nm x 20-50 nm short rod-like and 10-30 nm similar spherical HAP nanoparticles. The number-averaged particle size of stable suspension is about 30 nm between 11.6 and 110.5 nm and the zeta potential is -60.9 mV. The increase of stability of HAP nanoparticles suspension mainly depends on the electrostatic effect and steric effect of GAGs. The HAP nanoparticles can be easily transported into the cancer cells and exhibit good potential as gene or drug carrier system.

  4. Symmetric and Asymmetric Tendencies in Stable Complex Systems.

    Science.gov (United States)

    Tan, James P L

    2016-08-22

    A commonly used approach to study stability in a complex system is by analyzing the Jacobian matrix at an equilibrium point of a dynamical system. The equilibrium point is stable if all eigenvalues have negative real parts. Here, by obtaining eigenvalue bounds of the Jacobian, we show that stable complex systems will favor mutualistic and competitive relationships that are asymmetrical (non-reciprocative) and trophic relationships that are symmetrical (reciprocative). Additionally, we define a measure called the interdependence diversity that quantifies how distributed the dependencies are between the dynamical variables in the system. We find that increasing interdependence diversity has a destabilizing effect on the equilibrium point, and the effect is greater for trophic relationships than for mutualistic and competitive relationships. These predictions are consistent with empirical observations in ecology. More importantly, our findings suggest stabilization algorithms that can apply very generally to a variety of complex systems.

  5. The tempered stable process with infinitely divisible inverse subordinators

    International Nuclear Information System (INIS)

    Wyłomańska, Agnieszka

    2013-01-01

    In the last decade processes driven by inverse subordinators have become extremely popular. They have been used in many different applications, especially for data with observable constant time periods. However, the classical model, i.e. the subordinated Brownian motion, can be inappropriate for the description of observed phenomena that exhibit behavior not adequate for Gaussian systems. Therefore, in this paper we extend the classical approach and replace the Brownian motion by the tempered stable process. Moreover, on the other hand, as an extension of the classical model, we analyze the general class of inverse subordinators. We examine the main properties of the tempered stable process driven by inverse subordinators from the infinitely divisible class of distributions. We show the fractional Fokker–Planck equation of the examined process and the asymptotic behavior of the mean square displacement for two cases of subordinators. Additionally, we examine how an external force can influence the examined characteristics. (paper)

  6. Stable platinum isotope measurements in presolar nanodiamonds by TEAMS

    Energy Technology Data Exchange (ETDEWEB)

    Wallner, A., E-mail: anton.wallner@univie.ac.at [University of Vienna, Faculty of Physics, VERA Laboratory, Waehringer Strasse 17, A-1090 Vienna (Austria); Department of Nuclear Physics, Research School of Physics and Engineering, Australian National University, Canberra (Australia); Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights (Australia); Melber, K. [University of Vienna, Faculty of Physics, VERA Laboratory, Waehringer Strasse 17, A-1090 Vienna (Austria); Merchel, S. [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), D-01314 Dresden (Germany); Ott, U. [Max-Planck-Institut fuer Chemie, Joh.-J.-Becherweg 27, D-55128 Mainz (Germany); Forstner, O.; Golser, R.; Kutschera, W.; Priller, A.; Steier, P. [University of Vienna, Faculty of Physics, VERA Laboratory, Waehringer Strasse 17, A-1090 Vienna (Austria)

    2013-01-15

    Nanodiamonds are stardust grains commonly found in primitive meteorites. They survived the formation of the solar system and kept their own individuality. Measurements of trace-element isotopic signatures in these grains will help understanding heavy element nucleosynthesis in massive stars and dust formation from their ejecta. We have continued previous attempts to search for stable Pt isotope anomalies in nanodiamonds via trace element accelerator mass spectrometry (TEAMS). The installation of a new injector beam line at the VERA facility allowed studying low traces of stable elements in different materials. Moreover, recent experiments showed that VERA provides the required measurement precision together with a low Pt machine background. Here, we observed for the first time an indication for enhancements of {sup 198}Pt/{sup 195}Pt isotope ratios in two diamond residues prepared by different chemical separation techniques from the Allende meteorite. Variations in other isotopic ratios were within analytical uncertainty, and no anomaly was identified in a third diamond fraction.

  7. Stable platinum isotope measurements in presolar nanodiamonds by TEAMS

    International Nuclear Information System (INIS)

    Wallner, A.; Melber, K.; Merchel, S.; Ott, U.; Forstner, O.; Golser, R.; Kutschera, W.; Priller, A.; Steier, P.

    2013-01-01

    Nanodiamonds are stardust grains commonly found in primitive meteorites. They survived the formation of the solar system and kept their own individuality. Measurements of trace-element isotopic signatures in these grains will help understanding heavy element nucleosynthesis in massive stars and dust formation from their ejecta. We have continued previous attempts to search for stable Pt isotope anomalies in nanodiamonds via trace element accelerator mass spectrometry (TEAMS). The installation of a new injector beam line at the VERA facility allowed studying low traces of stable elements in different materials. Moreover, recent experiments showed that VERA provides the required measurement precision together with a low Pt machine background. Here, we observed for the first time an indication for enhancements of 198 Pt/ 195 Pt isotope ratios in two diamond residues prepared by different chemical separation techniques from the Allende meteorite. Variations in other isotopic ratios were within analytical uncertainty, and no anomaly was identified in a third diamond fraction.

  8. STICS: surface-tethered iterative carbohydrate synthesis.

    Science.gov (United States)

    Pornsuriyasak, Papapida; Ranade, Sneha C; Li, Aixiao; Parlato, M Cristina; Sims, Charles R; Shulga, Olga V; Stine, Keith J; Demchenko, Alexei V

    2009-04-14

    A new surface-tethered iterative carbohydrate synthesis (STICS) technology is presented in which a surface functionalized 'stick' made of chemically stable high surface area porous gold allows one to perform cost efficient and simple synthesis of oligosaccharide chains; at the end of the synthesis, the oligosaccharide can be cleaved off and the stick reused for subsequent syntheses.

  9. Palmitic acid/polypyrrole composites as form-stable phase change materials for thermal energy storage

    International Nuclear Information System (INIS)

    Silakhori, Mahyar; Metselaar, Hendrik Simon Cornelis; Mahlia, Teuku Meurah Indra; Fauzi, Hadi; Baradaran, Saeid; Naghavi, Mohammad Sajad

    2014-01-01

    Highlights: • A novel phase change composite of palmitic acid–polypyrrole(PA–PPy) was fabricated. • Thermal properties of PA–PPy are characterized in different mass ratios of PA–PPy. • Thermal cycling test showed that form stable PCM had a favorable thermal reliability. - Abstract: In this study a novel palmitic acid (PA)/polypyrrole (PPy) form-stable PCMs were readily prepared by in situ polymerization method. PA was used as thermal energy storage material and PPy was operated as supporting material. Form-stable PCMs were investigated by SEM (scanning electron microscopy) and FTIR (Fourier transform infrared spectrometer) analysis that illustrated PA Particles were wrapped by PPy particles. XRD (X-ray diffractometer) was used for crystalline phase of PA/PPy composites. Thermogravimetry analysis (TGA) and differential scanning calorimetry (DSC) were used for investigating Thermal stability and thermal energy storage properties of prepared form-stable PCMs. According to the obtained results the form stable PCMs exhibited favorable thermal stability in terms of their phase change temperature. The form-stable PCMs (79.9 wt% loading of PA) were considered as the highest loading PCM with desirable latent heat storage of 166.3 J/g and good thermal stability. Accelerated thermal cycling tests also showed that form stable PCM had an acceptable thermal reliability. As a consequence of acceptable thermal properties, thermal stability and chemical stability, we can consider the new kind of form stable PCMs for low temperature solar thermal energy storage applications

  10. Myopes show increased susceptibility to nearwork aftereffects.

    Science.gov (United States)

    Ciuffreda, K J; Wallis, D M

    1998-09-01

    Some aspects of accommodation may be slightly abnormal (or different) in myopes, compared with accommodation in emmetropes and hyperopes. For example, the initial magnitude of accommodative adaptation in the dark after nearwork is greatest in myopes. However, the critical test is to assess this initial accommodative aftereffect and its subsequent decay in the light under more natural viewing conditions with blur-related visual feedback present, if a possible link between this phenomenon and clinical myopia is to be considered. Subjects consisted of adult late- (n = 11) and early-onset (n = 13) myopes, emmetropes (n = 11), and hyperopes (n = 9). The distance-refractive state was assessed objectively using an autorefractor immediately before and after a 10-minute binocular near task at 20 cm (5 diopters [D]). Group results showed that myopes were most susceptible to the nearwork aftereffect. It averaged 0.35 D in initial magnitude, with considerably faster posttask decay to baseline in the early-onset (35 seconds) versus late-onset (63 seconds) myopes. There was no myopic aftereffect in the remaining two refractive groups. The myopes showed particularly striking accommodatively related nearwork aftereffect susceptibility. As has been speculated and found by many others, transient pseudomyopia may cause or be a precursor to permanent myopia or myopic progression. Time-integrated increased retinal defocus causing axial elongation is proposed as a possible mechanism.

  11. ATLAS collision event from the first LHC fill with stable beam on 17th April 2018

    CERN Multimedia

    ATLAS Collaboration

    2018-01-01

    Event display (run 348197, event 562578) from the first stable beam proton-proton collision run of 2018, recorded on April 17. Curved white lines show the trajectories of charged particles in the tracking systems.

  12. petrography, compositional characteristics and stable isotope ...

    African Journals Online (AJOL)

    PROF EKWUEME

    Subsurface samples of the predominantly carbonate Ewekoro Formation, obtained from Ibese core hole within the Dahomey basin were used in this study. Investigations entail petrographic, elemental composition as well as stable isotopes (carbon and oxygen) geochemistry in order to deduce the different microfacies and ...

  13. Working conditions remain stable in the Netherlands

    NARCIS (Netherlands)

    Houtman, I.; Hooftman, W.

    2008-01-01

    Despite significant changes in the national questionnaires on work and health, the quality of work as well as health complaints in the Netherlands appear to be relatively stable. Pace of work seems to be on the increase again and more people are working in excess of their contractual hours.

  14. Thermally stable sintered porous metal articles

    International Nuclear Information System (INIS)

    Gombach, A.L.; Thellmann, E.L.

    1980-01-01

    A sintered porous metal article is provided which is essentially thermally stable at elevated temperatures. In addition, a method for producing such an article is also provided which method comprises preparing a blend of base metal particles and active dispersoid particles, forming the mixture into an article of the desired shape, and heating the so-formed article at sintering temperatures

  15. TOF for heavy stable particle identification

    International Nuclear Information System (INIS)

    Chang, C.Y.

    1983-01-01

    Searching for heavy stable particle production in a new energy region of hadron-hadron collisions is of fundamental theoretical interest. Observation of such particles produced in high energy collisions would indicate the existence of stable heavy leptons or any massive hadronic system carrying new quantum numbers. Experimentally, evidence of its production has not been found for PP collisions either at FNAL or at the CERN ISR for √S = 23 and 62 GeV respectively. However, many theories beyond the standard model do predict its existence on a mass scale ranging from 50 to a few hundred GeV. If so, it would make a high luminosity TeV collider an extremely ideal hunting ground for searching the production of such a speculated object. To measure the mass of a heavy stable charged particle, one usually uses its time of flight (TOF) and/or dE/dX information. For heavy neutral particle, one hopes it may decay at some later time after its production. Hence a pair of jets or a jet associated with a high P/sub t/ muon originated from some places other than the interacting point (IP) of the colliding beams may be a good signal. In this note, we examine the feasibility of TOF measurement on a heavy stable particle produced in PP collisions at √S = 1 TeV and a luminosity of 10 33 cm -2 sec -1 with a single arm spectrometer pointing to the IP

  16. Exact simulation of max-stable processes.

    Science.gov (United States)

    Dombry, Clément; Engelke, Sebastian; Oesting, Marco

    2016-06-01

    Max-stable processes play an important role as models for spatial extreme events. Their complex structure as the pointwise maximum over an infinite number of random functions makes their simulation difficult. Algorithms based on finite approximations are often inexact and computationally inefficient. We present a new algorithm for exact simulation of a max-stable process at a finite number of locations. It relies on the idea of simulating only the extremal functions, that is, those functions in the construction of a max-stable process that effectively contribute to the pointwise maximum. We further generalize the algorithm by Dieker & Mikosch (2015) for Brown-Resnick processes and use it for exact simulation via the spectral measure. We study the complexity of both algorithms, prove that our new approach via extremal functions is always more efficient, and provide closed-form expressions for their implementation that cover most popular models for max-stable processes and multivariate extreme value distributions. For simulation on dense grids, an adaptive design of the extremal function algorithm is proposed.

  17. Unconditionally stable integration of Maxwell's equations

    NARCIS (Netherlands)

    Verwer, J.G.; Bochev, Mikhail A.

    Numerical integration of Maxwell's equations is often based on explicit methods accepting a stability step size restriction. In literature evidence is given that there is also a need for unconditionally stable methods, as exemplified by the successful alternating direction implicit finite difference

  18. Unconditionally stable integration of Maxwell's equations

    NARCIS (Netherlands)

    J.G. Verwer (Jan); M.A. Botchev

    2008-01-01

    htmlabstractNumerical integration of Maxwell''s equations is often based on explicit methods accepting a stability step size restriction. In literature evidence is given that there is also a need for unconditionally stable methods, as exemplified by the successful alternating direction

  19. Unconditionally stable integration of Maxwell's equations

    NARCIS (Netherlands)

    J.G. Verwer (Jan); M.A. Botchev

    2009-01-01

    textabstractNumerical integration of Maxwell’s equations is often based on explicit methods accepting a stability step size restriction. In literature evidence is given that there is also a need for unconditionally stable methods, as exemplified by the successful alternating direction implicit –

  20. Method of producing thermally stable uranium carbonitrides

    International Nuclear Information System (INIS)

    Ugajin, M.; Takahashi, I.

    1975-01-01

    A thermally stable uranium carbonitride can be produced by adding tungsten and/or molybdenum in the amount of 0.2 wt percent or more, preferably 0.5 wt percent or more, to a pure uranium carbonitride. (U.S.)

  1. Champion Island, Galapagos Stable Oxygen Calibration Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Galapagos Coral Stable Oxygen Calibration Data. Sites: Bartolome Island: 0 deg, 17 min S, 90 deg 33 min W. Champion Island: 1 deg, 15 min S, 90 deg, 05 min W. Urvina...

  2. 26 S proteasomes function as stable entities

    DEFF Research Database (Denmark)

    Hendil, Klavs B; Hartmann-Petersen, Rasmus; Tanaka, Keiji

    2002-01-01

    , shuttles between a free state and the 26-S proteasome, bringing substrate to the complex. However, S5a was not found in the free state in HeLa cells. Besides, all subunits in PA700, including S5a, exchanged at similar low rates. It therefore seems that 26-S proteasomes function as stable entities during...

  3. Formal derivation of a stable marriage algorithm.

    NARCIS (Netherlands)

    Bijlsma, A.

    1991-01-01

    In this paper the well-known Stable Marriage Problem is considered once again. The name of this programming problem comes from the terms in which it was first described [2]: A certain community consists of n men and n women. Each person ranks those of the opposite sex in accordance with his or

  4. Recurrent and multiple bladder tumors show conserved expression profiles

    International Nuclear Information System (INIS)

    Lindgren, David; Fioretos, Thoas; Månsson, Wiking; Höglund, Mattias; Gudjonsson, Sigurdur; Jee, Kowan Ja; Liedberg, Fredrik; Aits, Sonja; Andersson, Anna; Chebil, Gunilla; Borg, Åke; Knuutila, Sakari

    2008-01-01

    Urothelial carcinomas originate from the epithelial cells of the inner lining of the bladder and may appear as single or as multiple synchronous tumors. Patients with urothelial carcinomas frequently show recurrences after treatment making follow-up necessary. The leading hypothesis explaining the origin of meta- and synchronous tumors assumes a monoclonal origin. However, the genetic relationship among consecutive tumors has been shown to be complex in as much as the genetic evolution does not adhere to the chronological appearance of the metachronous tumors. Consequently, genetically less evolved tumors may appear chronologically later than genetically related but more evolved tumors. Forty-nine meta- or synchronous urothelial tumors from 22 patients were analyzed using expression profiling, conventional CGH, LOH, and mutation analyses. We show by CGH that partial chromosomal losses in the initial tumors may not be present in the recurring tumors, by LOH that different haplotypes may be lost and that detected regions of LOH may be smaller in recurring tumors, and that mutations present in the initial tumor may not be present in the recurring ones. In contrast we show that despite apparent genomic differences, the recurrent and multiple bladder tumors from the same patients display remarkably similar expression profiles. Our findings show that even though the vast majority of the analyzed meta- and synchronous tumors from the same patients are not likely to have originated directly from the preceding tumor they still show remarkably similar expressions profiles. The presented data suggests that an expression profile is established early in tumor development and that this profile is stable and maintained in recurring tumors

  5. On Nash-Equilibria of Approximation-Stable Games

    Science.gov (United States)

    Awasthi, Pranjal; Balcan, Maria-Florina; Blum, Avrim; Sheffet, Or; Vempala, Santosh

    One reason for wanting to compute an (approximate) Nash equilibrium of a game is to predict how players will play. However, if the game has multiple equilibria that are far apart, or ɛ-equilibria that are far in variation distance from the true Nash equilibrium strategies, then this prediction may not be possible even in principle. Motivated by this consideration, in this paper we define the notion of games that are approximation stable, meaning that all ɛ-approximate equilibria are contained inside a small ball of radius Δ around a true equilibrium, and investigate a number of their properties. Many natural small games such as matching pennies and rock-paper-scissors are indeed approximation stable. We show furthermore there exist 2-player n-by-n approximation-stable games in which the Nash equilibrium and all approximate equilibria have support Ω(log n). On the other hand, we show all (ɛ,Δ) approximation-stable games must have an ɛ-equilibrium of support O(Δ^{2-o(1)}/ɛ2{log n}), yielding an immediate n^{O(Δ^{2-o(1)}/ɛ^2log n)}-time algorithm, improving over the bound of [11] for games satisfying this condition. We in addition give a polynomial-time algorithm for the case that Δ and ɛ are sufficiently close together. We also consider an inverse property, namely that all non-approximate equilibria are far from some true equilibrium, and give an efficient algorithm for games satisfying that condition.

  6. Ancient bacteria show evidence of DNA repair

    DEFF Research Database (Denmark)

    Johnson, Sarah Stewart; Hebsgaard, Martin B; Christensen, Torben R

    2007-01-01

    -term survival of bacteria sealed in frozen conditions for up to one million years. Our results show evidence of bacterial survival in samples up to half a million years in age, making this the oldest independently authenticated DNA to date obtained from viable cells. Additionally, we find strong evidence...... geological timescales. There has been no direct evidence in ancient microbes for the most likely mechanism, active DNA repair, or for the metabolic activity necessary to sustain it. In this paper, we couple PCR and enzymatic treatment of DNA with direct respiration measurements to investigate long...... that this long-term survival is closely tied to cellular metabolic activity and DNA repair that over time proves to be superior to dormancy as a mechanism in sustaining bacteria viability....

  7. Microbiological and environmental issues in show caves.

    Science.gov (United States)

    Saiz-Jimenez, Cesareo

    2012-07-01

    Cultural tourism expanded in the last half of the twentieth century, and the interest of visitors has come to include caves containing archaeological remains. Some show caves attracted mass tourism, and economical interests prevailed over conservation, which led to a deterioration of the subterranean environment and the rock art. The presence and the role of microorganisms in caves is a topic that is often ignored in cave management. Knowledge of the colonisation patterns, the dispersion mechanisms, and the effect on human health and, when present, over rock art paintings of these microorganisms is of the utmost importance. In this review the most recent advances in the study of microorganisms in caves are presented, together with the environmental implications of the findings.

  8. Strontium stable isotope behaviour accompanying basalt weathering

    Science.gov (United States)

    Burton, K. W.; Parkinson, I. J.; Gíslason, S. G. R.

    2016-12-01

    The strontium (Sr) stable isotope composition of rivers is strongly controlled by the balance of carbonate to silicate weathering (Krabbenhöft et al. 2010; Pearce et al. 2015). However, rivers draining silicate catchments possess distinctly heavier Sr stable isotope values than their bedrock compositions, pointing to significant fractionation during weathering. Some have argued for preferential release of heavy Sr from primary phases during chemical weathering, others for the formation of secondary weathering minerals that incorporate light isotopes. This study presents high-precision double-spike Sr stable isotope data for soils, rivers, ground waters and estuarine waters from Iceland, reflecting both natural weathering and societal impacts on those environments. The bedrock in Iceland is dominantly basaltic, d88/86Sr ≈ +0.27, extending to lighter values for rhyolites. Geothermal waters range from basaltic Sr stable compositions to those akin to seawater. Soil pore waters reflect a balance of input from primary mineral weathering, precipitation and litter recycling and removal into secondary phases and vegetation. Rivers and ground waters possess a wide range of d88/86Sr compositions from +0.101 to +0.858. Elemental and isotope data indicate that this fractionation primarily results from the formation or dissolution of secondary zeolite (d88/86Sr ≈ +0.10), but also carbonate (d88/86Sr ≈ +0.22) and sometimes anhydrite (d88/86Sr ≈ -0.73), driving the residual waters to heavier or lighter values, respectively. Estuarine waters largely reflect mixing with seawater, but are also be affected by adsorption onto particulates, again driving water to heavy values. Overall, these data indicate that the stability and nature of secondary weathering phases, exerts a strong control on the Sr stable isotope composition of silicate rivers. [1] Krabbenhöft et al. (2010) Geochim. Cosmochim. Acta 74, 4097-4109. [2] Pearce et al. (2015) Geochim. Cosmochim. Acta 157, 125-146.

  9. Tellurium Stable Isotopes as a Paleoredox Proxy

    Science.gov (United States)

    Wasserman, N.; Johnson, T. M.

    2017-12-01

    Despite arguments for variably-oxygenated shallow waters and anoxic deep marine waters, which delayed animal development until the Neoproterozoic Oxidation Event, the magnitude of atmospheric oxygen during the Proterozoic is still uncertain [1]. The evidence for low pO2 (<0.1-1% PAL) is based on geochemical and isotopic proxies, which track the mobilization of Fe and Mn on the continents. For example, large chromium isotope shifts occur at the Neoproterozoic Oxidation Event due to the initiation of Cr redox cycling, but this proxy is insensitive to fluctuations in the lower-pO2 conditions at other times during the Proterozoic. Tellurium, a metalloid with a lower threshold to oxidation, may be sensitive to pO2 shifts in a lower range. In the reduced forms, Te(-II) and Te(0), the element is insoluble and immobile. However, in the more oxidized phases, Te(IV) and Te(VI), Te can form soluble oxyanions (though it tends to adsorb to Fe-oxyhydroxides and clays) [2]. Te stable isotopes have been shown to fractionate during abiotic or biologic reduction of Te(VI) or Te(IV) to elemental Te(0) [3, 4]. Utilizing hydride generation MC-ICP-MS, we are able to obtain high precision (2σ 0.04‰) measurements of δ128Te/125Te for natural samples containing < 10 ng of Te. A suite of Phanerozoic and Proterozoic ironstones show significant variation in δ128Te/125Te (<0.5‰), suggesting that the Te redox cycle was active during the Proterozoic. Future directions will include Te isotope measurements of Precambrian paleosols to determine natural isotope variation before the Great Oxidation Event and experiments to determine fractionation during adsorption to Fe-oxyhydroxides. [1] Planavsky et al. (2014) Science 346 (6209), pp. 635-638 [2] Qin et al. (2017) Environmental Science and Technology 51 (11), pp 6027-6035 [3] Baesman et al. (2007) Applied Environmental Microbiology 73 (7), pp 2135-2143 [4] Smithers and Krause (1968) Canadian Journal of Chemistry 46(4): pp 583-591

  10. Comparative biogeochemical behaviors of iron-55 and stable iron in the marine environment

    International Nuclear Information System (INIS)

    Weimer, W.C.; Langford, J.C.; Jenkins, C.E.

    1978-01-01

    Studies of atmospheric aerosols have demonstrated that much of the 55 Fe associated with the aerosol input to the oceans is present as either an amorphous or hydrous iron oxide or as very small particulate species attached to the surfaces of the large aerosol particles. By comparison, nearly all of the stable iron is bound in the mineral phase of aerosol particles. This difference in the chemical and physical forms of the radioactive and stable iron isotopes results in the 55 Fe being more biologically available than is the stable iron. This difference in availability is responsible for the transfer of a much higher specific activity 55 Fe to certain ocean organisms and man relative to the specific activity of the total aerosol or of sea water. This differential biological uptake of the radioactive element and its stable element counterpart points out that natural levels of stable elements in the marine environment may not effectively dilute radioelements or other stable elements of anthropogenic sources. The effectiveness of dilution by natural sources depends on the chemical and physical forms of the materials in both the source terms and the receiving environments. The large difference in specific activities of 55 Fe in aerosols and sea water relative to ocean organisms reflects the independent behaviors of 55 Fe and stable iron

  11. Surface-Controlled Metal Oxide Resistive Memory

    KAUST Repository

    Ke, Jr-Jian; Namura, Kyoko; Duran Retamal, Jose Ramon; Ho, Chin-Hsiang; Minamitake, Haruhiko; Wei, Tzu-Chiao; Tsai, Dung-Sheng; Lin, Chun-Ho; Suzuki, Motofumi; He, Jr-Hau

    2015-01-01

    be attributed to the stable oxygen adatoms under various ambience conditions. The findings validate the surface-controlled stability and uniformity of ReRAM and can serve as the guideline for developing practical device applications.

  12. Mechanics of active surfaces

    Science.gov (United States)

    Salbreux, Guillaume; Jülicher, Frank

    2017-09-01

    We derive a fully covariant theory of the mechanics of active surfaces. This theory provides a framework for the study of active biological or chemical processes at surfaces, such as the cell cortex, the mechanics of epithelial tissues, or reconstituted active systems on surfaces. We introduce forces and torques acting on a surface, and derive the associated force balance conditions. We show that surfaces with in-plane rotational symmetry can have broken up-down, chiral, or planar-chiral symmetry. We discuss the rate of entropy production in the surface and write linear constitutive relations that satisfy the Onsager relations. We show that the bending modulus, the spontaneous curvature, and the surface tension of a passive surface are renormalized by active terms. Finally, we identify active terms which are not found in a passive theory and discuss examples of shape instabilities that are related to active processes in the surface.

  13. Identification of trophic interactions within an estuarine food web (northern New Zealand) using fatty acid biomarkers and stable isotopes

    Science.gov (United States)

    Alfaro, Andrea C.; Thomas, François; Sergent, Luce; Duxbury, Mark

    2006-10-01

    Fatty acid biomarkers and stable isotope signatures were used to identify the trophic dynamics of a mangrove/seagrass estuarine food web at Matapouri, northern New Zealand. Specific fatty acids were used to identify the preferred food sources (i.e., mangroves, seagrass, phytoplankton, macroalgae, bacteria, and zooplankton) of dominant fauna (i.e., filter feeders, grazing snails, scavenger/predatory snails, shrimp, crabs, and fish), and their presence in water and sediment samples throughout the estuary. The diets of filter feeders were found to be dominated by dinoflagellates, whereas grazers showed a higher diatom contribution. Bacteria associated with organic debris on surface sediments and brown algal ( Hormosira banksii) material in the form of suspended organic matter also accounted for a high proportion of most animal diets. Animals within higher trophic levels had diverse fatty acid profiles, revealing their varied feeding strategies and carbon sources. The stable isotope (δ 13C and δ 15N) analyses of major primary producers and consumers/predators revealed a trend of 15N enrichment with increasing trophic level, while δ 13C values provided a generally good description of carbon flow through the food web. Overall results from both fatty acid profiles and stable isotopes indicate that a variety of carbon sources with a range of trophic pathways typify this food web. Moreover, none of the animals studied was dependent on a single food source. This study is the first to use a comprehensive fatty acid biomarker and stable isotope approach to investigate the food web dynamics within a New Zealand temperate mangrove/seagrass estuary. This quantitative research may contribute to the currently developing management strategies for estuaries in northern New Zealand, especially for those perceived to have expanding mangrove fringes.

  14. CO oxidation on PdO surfaces

    DEFF Research Database (Denmark)

    Hirvi, Janne T.; Kinnunen, Toni-Jani J.; Suvanto, Mika

    2010-01-01

    Density functional calculations were performed in order to investigate CO oxidation on two of the most stable bulk PdO surfaces. The most stable PdO(100) surface, with oxygen excess, is inert against CO adsorption, whereas strong adsorption on the stoichiometric PdO(101) surface leads to favorable...... oxidation via the Langmuir–Hinshelwood mechanism. The reaction with a surface oxygen atom has an activation energy of 0.66 eV, which is comparable to the lowest activation energies observed on metallic surfaces. However, the reaction rate may be limited by the coverage of molecular oxygen. Actually...... adsorption, following the Eley–Rideal mechanism and taking advantage of the reaction tunnel provided by the adjacent palladium atom, has an activation energy of only 0.24 eV. The reaction mechanism and activation energy for the palladium activated CO oxidation on the most stable PdO(100)–O surface...

  15. Development of a Safety Management Web Tool for Horse Stables.

    Science.gov (United States)

    Leppälä, Jarkko; Kolstrup, Christina Lunner; Pinzke, Stefan; Rautiainen, Risto; Saastamoinen, Markku; Särkijärvi, Susanna

    2015-11-12

    Managing a horse stable involves risks, which can have serious consequences for the stable, employees, clients, visitors and horses. Existing industrial or farm production risk management tools are not directly applicable to horse stables and they need to be adapted for use by managers of different types of stables. As a part of the InnoEquine project, an innovative web tool, InnoHorse, was developed to support horse stable managers in business, safety, pasture and manure management. A literature review, empirical horse stable case studies, expert panel workshops and stakeholder interviews were carried out to support the design. The InnoHorse web tool includes a safety section containing a horse stable safety map, stable safety checklists, and examples of good practices in stable safety, horse handling and rescue planning. This new horse stable safety management tool can also help in organizing work processes in horse stables in general.

  16. The interdependence between the incidence angles associated with quasi-stable intersections during ion erosion

    International Nuclear Information System (INIS)

    Vasiliu, F.; Frunza, S.

    1984-01-01

    A general discussion, which is valid for any angular dependence of sputtering yield S = S(theta), concerning the interdependence between the incidence angles thetasub(e) and theta 0 , associated with quasi-stable intersections during ion erosion, is given. The object was firstly to establish the location of thetasub(e) roots as a function of theta 0 and secondly to identify the stationary points and general trend for the complex dependence thetasub(e) = thetasub(e)(theta 0 ). The results obtained are applied to a quasi-stability analysis of some specific surface features during ion erosion. Various possible types of quasi-stable intersections (surface-surface, plane-surface, plane-plane) are reviewed from the point of view of their evolution caused by ion bombardment. (author)

  17. Preparation, Characterization and Thermal Properties of Paraffin Wax – Expanded Perlite Form-Stable Composites for Latent Heat Storage

    Directory of Open Access Journals (Sweden)

    Tugba GURMEN OZCELIK

    2017-02-01

    Full Text Available In this study, form-stable composite phase change materials (PCM for latent heat storage were prepared by impregnating paraffin wax into the pores of the expanded perlite (EP. The characterization of the composite PCMs was performed by FTIR, TGA, SEM and DSC analysis. The melting point and heat of fusion were determined for 25 % paraffin included composite, as 54.3 °C and 94.71 J/g and for 45 % paraffin included composite as 53.6 °C and 106.69 J/g, respectively. The FTIR results showed that there were no chemical reaction between the perlite and paraffin. TGA analysis indicated that both composite PCMs had good thermal stability. SEM images showed that the paraffin was dispersed uniformly into the pores and on the EP surface. There was no leakage and degradation at the composite PCMs after heating and cooling cycles. According to the results, both prepared composites showed good thermal energy storage properties, reliability and stability. All results suggested that the presented form- stable composite PCMs has great potential for thermal energy storage applications.DOI: http://dx.doi.org/10.5755/j01.ms.23.1.13661

  18. NASA GIBS Use in Live Planetarium Shows

    Science.gov (United States)

    Emmart, C. B.

    2015-12-01

    The American Museum of Natural History's Hayden Planetarium was rebuilt in year 2000 as an immersive theater for scientific data visualization to show the universe in context to our planet. Specific astrophysical movie productions provide the main daily programming, but interactive control software, developed at AMNH allows immersive presentation within a data aggregation of astronomical catalogs called the Digital Universe 3D Atlas. Since 2006, WMS globe browsing capabilities have been built into a software development collaboration with Sweden's Linkoping University (LiU). The resulting Uniview software, now a product of the company SCISS, is operated by about fifty planetariums around that world with ability to network amongst the sites for global presentations. Public presentation of NASA GIBS has allowed authoritative narratives to be presented within the range of data available in context to other sources such as Science on a Sphere, NASA Earth Observatory and Google Earth KML resources. Specifically, the NOAA supported World Views Network conducted a series of presentations across the US that focused on local ecological issues that could then be expanded in the course of presentation to national and global scales of examination. NASA support of for GIBS resources in an easy access multi scale streaming format like WMS has tremendously enabled particularly facile presentations of global monitoring like never before. Global networking of theaters for distributed presentations broadens out the potential for impact of this medium. Archiving and refinement of these presentations has already begun to inform new types of documentary productions that examine pertinent, global interdependency topics.

  19. Relating surface chemistry and oxygen surface exchange in LnBaCo2O(5+δ) air electrodes.

    Science.gov (United States)

    Téllez, Helena; Druce, John; Kilner, John A; Ishihara, Tatsumi

    2015-01-01

    The surface and near-surface chemical composition of electroceramic materials often shows significant deviations from that of the bulk. In particular, layered materials, such as cation-ordered LnBaCo2O(5+δ) perovskites (Ln = lanthanide), undergo surface and sub-surface restructuring due to the segregation of the divalent alkaline-earth cation. These processes can take place during synthesis and processing steps (e.g. deposition, sintering or annealing), as well as at temperatures relevant for the operation of these materials as air electrodes in solid oxide fuel cells and electrolysers. Furthermore, the surface segregation in these double perovskites shows fast kinetics, starting at temperatures as low as 400 °C over short periods of time and leading to a decrease in the transition metal surface coverage exposed to the gas phase. In this work, we use a combination of stable isotope tracer labeling and surface-sensitive ion beam techniques to study the oxygen transport properties and their relationship with the surface chemistry in ordered LnBaCo2O(5+δ) perovskites. Time-of-Flight Secondary-Ion Mass Spectrometry (ToF-SIMS) combined with (18)O isotope exchange was used to determine the oxygen tracer diffusion (D*) and surface exchange (k*) coefficients. Furthermore, Low Energy Ion Scattering (LEIS) was used for the analysis of the surface and near surface chemistry as it provides information from the first mono-atomic layer of the materials. In this way, we could relate the compositional modifications (e.g. cation segregation) taking place at the electrochemically-active surface during the exchange at high temperatures and the oxygen transport properties in double perovskite electrode materials to further our understanding of the mechanism of the surface exchange process.

  20. DAST in Flight Showing Diverging Wingtip Oscillations

    Science.gov (United States)

    1980-01-01

    normal stiffness. This was done because stiffness requires structural weight but ensures freedom from flutter-an uncontrolled, divergent oscillation of the structure, driven by aerodynamic forces and resulting in structural failure. The program used refined theoretical tools to predict at what speed flutter would occur. It then designed a high-response control system to counteract the motion and permit a much lighter wing structure. The wing had, in effect, 'electronic stiffness.' Flight research with this concept was extremely hazardous because an error in either the flutter prediction or control system implementation would result in wing structural failure and the loss of the vehicle. Because of this, flight demonstration of a sub-scale vehicle made sense from the standpoint of both safety and cost. The program anticipated structural failure during the course of the flight research. The Firebee II was a supersonic drone selected as the DAST testbed because its wing could be easily replaced, it used only tail-mounted control surfaces, and it was available as surplus from the U. S. Air Force. It was capable of 5-g turns (that is, turns producing acceleration equal to 5 times that of gravity). Langley outfitted a drone with an aeroelastic, supercritical research wing suitable for a Mach 0.98 cruise transport with a predicted flutter speed of Mach 0.95 at an altitude of 25,000 feet. Dryden and Langley, in conjunction with Boeing, designed and fabricated a digital flutter suppression system (FSS). Dryden developed an RPRV (remotely piloted research vehicle) flight control system; integrated the wing, FSS, and vehicle systems; and conducted the flight program. In addition to a digital flight control system and aeroelastic wings, each DAST drone had research equipment mounted in its nose and a mid-air retrieval system in its tail. The drones were originally launched from the NASA B-52 bomber and later from a DC-130. The DAST vehicle's flight was monitored from the sky by an F

  1. Geoscience is Important? Show Me Why

    Science.gov (United States)

    Boland, M. A.

    2017-12-01

    "The public" is not homogenous and no single message or form of messaging will connect the entire public with the geosciences. One approach to promoting trust in, and engagement with, the geosciences is to identify specific sectors of the public and then develop interactions and communication products that are immediately relevant to that sector's interests. If the content and delivery are appropriate, this approach empowers people to connect with the geosciences on their own terms and to understand the relevance of the geosciences to their own situation. Federal policy makers are a distinct and influential subgroup of the general public. In preparation for the 2016 presidential election, the American Geosciences Institute (AGI) in collaboration with its 51 member societies prepared Geoscience for America's Critical Needs: Invitation to a National Dialogue, a document that identified major geoscience policy issues that should be addressed in a national policy platform. Following the election, AGI worked with eight other geoscience societies to develop Geoscience Policy Recommendations for the New Administration and the 115th Congress, which outlines specific policy actions to address national issues. State and local decision makers are another important subgroup of the public. AGI has developed online content, factsheets, and case studies with different levels of technical complexity so people can explore societally-relevant geoscience topics at their level of technical proficiency. A related webinar series is attracting a growing worldwide audience from many employment sectors. Partnering with government agencies and other scientific and professional societies has increased the visibility and credibility of these information products with our target audience. Surveys and other feedback show that these products are raising awareness of the geosciences and helping to build reciprocal relationships between geoscientists and decision makers. The core message of all

  2. Bacteriophages show promise as antimicrobial agents.

    Science.gov (United States)

    Alisky, J; Iczkowski, K; Rapoport, A; Troitsky, N

    1998-01-01

    The emergence of antibiotic-resistant bacteria has prompted interest in alternatives to conventional drugs. One possible option is to use bacteriophages (phage) as antimicrobial agents. We have conducted a literature review of all Medline citations from 1966-1996 that dealt with the therapeutic use of phage. There were 27 papers from Poland, the Soviet Union, Britain and the U.S.A. The Polish and Soviets administered phage orally, topically or systemically to treat a wide variety of antibiotic-resistant pathogens in both adults and children. Infections included suppurative wound infections, gastroenteritis, sepsis, osteomyelitis, dermatitis, empyemas and pneumonia; pathogens included Staphylococcus, Streptococcus, Klebsiella, Escherichia, Proteus, Pseudomonas, Shigella and Salmonella spp. Overall, the Polish and Soviets reported success rates of 80-95% for phage therapy, with rare, reversible gastrointestinal or allergic side effects. However, efficacy of phage was determined almost exclusively by qualitative clinical assessment of patients, and details of dosages and clinical criteria were very sketchy. There were also six British reports describing controlled trials of phage in animal models (mice, guinea pigs and livestock), measuring survival rates and other objective criteria. All of the British studies raised phage against specific pathogens then used to create experimental infections. Demonstrable efficacy against Escherichia, Acinetobacter, Pseudomonas and Staphylococcus spp. was noted in these model systems. Two U.S. papers dealt with improving the bioavailability of phage. Phage is sequestered in the spleen and removed from circulation. This can be overcome by serial passage of phage through mice to isolate mutants that resist sequestration. In conclusion, bacteriophages may show promise for treating antibiotic resistant pathogens. To facilitate further progress, directions for future research are discussed and a directory of authors from the reviewed

  3. Bare and protected sputtered-noble-metal films for surface-enhanced Raman spectroscopy

    Science.gov (United States)

    Talaga, David; Bonhommeau, Sébastien

    2014-11-01

    Sputtered silver and gold films with different surface morphologies have been prepared and coated with a benzenethiol self-assembled monolayer. Rough noble metal films showed strong Raman features assigned to adsorbed benzenethiol molecules upon irradiation over a wide energy range in the visible spectrum, which disclosed the occurrence of a significant surface-enhanced Raman scattering with maximal enhancement factors as high as 6 × 106. In addition, the adsorption of ethanethiol onto silver surfaces hinders their corrosion over days while preserving mostly intact enhancement properties of naked silver. This study may be applied to develop stable and efficient metalized probes for tip-enhanced Raman spectroscopy.

  4. Unraveling the oxygen vacancy structures at the reduced Ce O2(111 ) surface

    Science.gov (United States)

    Han, Zhong-Kang; Yang, Yi-Zhou; Zhu, Beien; Ganduglia-Pirovano, M. Verónica; Gao, Yi

    2018-03-01

    Oxygen vacancies at ceria (Ce O2 ) surfaces play an essential role in catalytic applications. However, during the past decade, the near-surface vacancy structures at Ce O2(111 ) have been questioned due to the contradictory results from experiments and theoretical simulations. Whether surface vacancies agglomerate, and which is the most stable vacancy structure for varying vacancy concentration and temperature, are being heatedly debated. By combining density functional theory calculations and Monte Carlo simulations, we proposed a unified model to explain all conflicting experimental observations and theoretical results. We find a novel trimeric vacancy structure which is more stable than any other one previously reported, which perfectly reproduces the characteristics of the double linear surface oxygen vacancy clusters observed by STM. Monte Carlo simulations show that at low temperature and low vacancy concentrations, vacancies prefer subsurface sites with a local (2 × 2) ordering, whereas mostly linear surface vacancy clusters do form with increased temperature and degree of reduction. These results well explain the disputes about the stable vacancy structure and surface vacancy clustering at Ce O2(111 ) , and provide a foundation for the understanding of the redox and catalytic chemistry of metal oxides.

  5. Comparing Stable Water Isotope Variation in Atmospheric Moisture Observed over Coastal Water and Forests

    Science.gov (United States)

    Lai, C. T.; Rambo, J. P.; Welp, L. R.; Bible, K.; Hollinger, D. Y.

    2014-12-01

    Stable oxygen (δ18O) and hydrogen (δD) isotopologues of atmospheric moisture are strongly influenced by large-scale synoptic weather cycles, surface evapotranspiration and boundary layer mixing. Atmospheric water isotope variation has been shown to empirically relate to relative humidity (Rh) of near surface moisture, and to a less degree, air temperature. Continuous δ18O and δD measurements are becoming more available, providing new opportunities to investigate processes that control isotope variability. This study shows the comparison of δ18O and δD measured at a continental location and over coastal waters for 3 seasons (spring to fall, 2014). The surface moisture isotope measurements were made using two LGR spectroscopy water vapor isotope analyzers (Los Gatos Research Inc.), one operated in an old-growth coniferous forest at Wind River field station, WA (45.8205°N, 121.9519°W), and another sampling marine air over seawater at the Scripps Pier in San Diego, CA (32.8654°N, 117.2536°W), USA. Isotope variations were measured at 1Hz and data were reported as hourly averages with an overall accuracy of ±0.1‰ for δ18O, ±0.5‰ for δ2H. Day-to-day variations in δ18O and δD are shown strongly influenced by synoptic weather events at both locations. Boundary layer mixing between surface moisture and the dry air entrained from the free troposphere exerts a midday maximum and a consistent diel pattern in deuterium excess (dx). At the forest site, surface moisture also interacts with leaf water through transpiration during the day and re-equilibration at night. The latter occurs by retro-diffusion of atmospheric H2O molecules into leaf intercellular space, which becomes intensified as Rh increaes after nightfall, and continues until sunrise, to counter-balance the evaporative isotopic enrichment in leaf water on a daily basis. These vegetation effects lead to negative dx values consistently observed at nighttime in this continental location that were not

  6. Stable water isotope patterns in a climate change hotspot: the isotope hydrology framework of Corsica (western Mediterranean).

    Science.gov (United States)

    van Geldern, Robert; Kuhlemann, Joachim; Schiebel, Ralf; Taubald, Heinrich; Barth, Johannes A C

    2014-06-01

    The Mediterranean is regarded as a region of intense climate change. To better understand future climate change, this area has been the target of several palaeoclimate studies which also studied stable isotope proxies that are directly linked to the stable isotope composition of water, such as tree rings, tooth enamel or speleothems. For such work, it is also essential to establish an isotope hydrology framework of the region of interest. Surface waters from streams and lakes as well as groundwater from springs on the island of Corsica were sampled between 2003 and 2009 for their oxygen and hydrogen isotope compositions. Isotope values from lake waters were enriched in heavier isotopes and define a local evaporation line (LEL). On the other hand, stream and spring waters reflect the isotope composition of local precipitation in the catchment. The intersection of the LEL and the linear fit of the spring and stream waters reflect the mean isotope composition of the annual precipitation (δP) with values of-8.6(± 0.2) ‰ for δ(18)O and-58(± 2) ‰ for δ(2)H. This value is also a good indicator of the average isotope composition of the local groundwater in the island. Surface water samples reflect the altitude isotope effect with a value of-0.17(± 0.02) ‰ per 100 m elevation for oxygen isotopes. At Vizzavona Pass in central Corsica, water samples from two catchments within a lateral distance of only a few hundred metres showed unexpected but systematic differences in their stable isotope composition. At this specific location, the direction of exposure seems to be an important factor. The differences were likely caused by isotopic enrichment during recharge in warm weather conditions in south-exposed valley flanks compared to the opposite, north-exposed valley flanks.

  7. Changes in contact angle providing evidence for surface alteration in multi-component solid foods

    International Nuclear Information System (INIS)

    Reinke, Svenja K; Hauf, Katharina; Heinrich, Stefan; Vieira, Josélio; Palzer, Stefan

    2015-01-01

    Chocolate blooming, one of the major problems in the confectionery industry, is the formation of visible white spots or a greyish haze on the surface of chocolate products due to large sugar or fat crystals on the surface. This leads to aesthetic changes and deterioration of taste and thus large sales losses for the confectionery industry due to consumer complaints. Chocolate blooming is often related to migration of lipids or sugar molecules to the chocolate surface, where they recrystallize with an associated polymorphic change of crystal structure on the surface. The wetting behaviour from contact angle measurements gives further insight into surface properties and is needed to determine surface energies and to evaluate possible migration mechanisms and preferred pathways. Therefore, an equilibrium contact angle is needed which is not directly accessible and is influenced by surface texture and interaction between solid and test liquid. In this study, the surface of cocoa butter and conventional chocolates was characterized by measuring the contact angle with the sessile drop protocol. The influence of roughness, test liquid and pre-crystallization of the samples as well as the storage temperature were investigated. In case of no pre-crystallization, a change in surface properties due to storage at 20 °C was detected, whereas samples stored at 30 °C showed the same wetting behaviour as fresh samples. This is associated with polymorphic transformation from thermodynamically less stable crystals to more stable configurations. (paper)

  8. Changes in contact angle providing evidence for surface alteration in multi-component solid foods

    Science.gov (United States)

    Reinke, Svenja K.; Hauf, Katharina; Vieira, Josélio; Heinrich, Stefan; Palzer, Stefan

    2015-11-01

    Chocolate blooming, one of the major problems in the confectionery industry, is the formation of visible white spots or a greyish haze on the surface of chocolate products due to large sugar or fat crystals on the surface. This leads to aesthetic changes and deterioration of taste and thus large sales losses for the confectionery industry due to consumer complaints. Chocolate blooming is often related to migration of lipids or sugar molecules to the chocolate surface, where they recrystallize with an associated polymorphic change of crystal structure on the surface. The wetting behaviour from contact angle measurements gives further insight into surface properties and is needed to determine surface energies and to evaluate possible migration mechanisms and preferred pathways. Therefore, an equilibrium contact angle is needed which is not directly accessible and is influenced by surface texture and interaction between solid and test liquid. In this study, the surface of cocoa butter and conventional chocolates was characterized by measuring the contact angle with the sessile drop protocol. The influence of roughness, test liquid and pre-crystallization of the samples as well as the storage temperature were investigated. In case of no pre-crystallization, a change in surface properties due to storage at 20 °C was detected, whereas samples stored at 30 °C showed the same wetting behaviour as fresh samples. This is associated with polymorphic transformation from thermodynamically less stable crystals to more stable configurations.

  9. Towards hydrochemical PUB - stable vs. heterogeneous NO3 and COD signatures across hydrographic structure and size

    Science.gov (United States)

    Ecrepont, Stephane; Cudennec, Christophe; Jaffrezic, Anne; de Lavenne, Alban

    2017-04-01

    Towards hydrochemical PUB - stable vs. heterogeneous NO3 and DOC signatures across hydrographic structure and size Ecrepont, S.1Cudennec, C.1 Jaffrézic, A.1 de Lavenne, A.2 1UMR SAS, Agrocampus Ouest, Rennes, France 2 HBAN, Irstea, Antony, France Intensive agriculture is a major disturbing factor for water quality in Brittany, France. Observations of chemical data from 350 catchments over a 15 year period show that the high variability of hydrochemical dynamics between catchments in relation to geographic characteristics and farming practices, decreases with an increase in the catchment size. A stable signature of nitrate and DOC dynamics does emerge for bigger catchments, and was evidenced statistically. We adapted a modified version of the standard deviation formula to calculate an index on mean inter-annual winter nitrate and dissolved organic carbon concentrations to characterize each catchment. The method was applied to the whole sample of catchments, some of them nested, to investigate variation of our new index across scales and regions. Results show an increasing and non-linear relationship between the criterion and the surface, with threshold effects. The stability of the thresholds across river basins in Brittany, and across seasons and years is explored. This emergence relates to the progressive connection of streams with heterogeneous characteristic chemical signatures into a mixing dominant effect. The better assessment of this relationship opens two major perspectives: i) to define a geomorphology-based PUB (Prediction in Ungauged Basins) approach for hydrochemistry; ii) to identify the most critical sub-catchments for mitigating actions in terms of farming and landscape practices towards water quality recovery.

  10. Stable Superstring Relics and Ultrahigh Energy Cosmic Rays

    CERN Document Server

    Coriano, Claudio; Plumacher, Michael; Coriano, Claudio; Faraggi, Alon E.; Plumacher, Michael

    2001-01-01

    One of the most intriguing experimental results of recent years is the observation of Ultrahigh Energy Cosmic Rays (UHECRs) above the GZK cutoff. Plausible candidates for the UHECR primaries are the decay products of a meta--stable matter state with mass of order O(10^{12-15 GeV}), which simultaneously is a good cold dark matter candidate. We study possible meta-stable matter states that arise from Wilson line breaking of GUT symmetries in semi-realistic heterotic string models. In the models that we study the exotic matter states can be classified according to patterns of SO(10) symmetry breaking. We show that cryptons, which are states that carry fractional electric charge $\\pm1/2$, and are confined by a hidden gauge group cannot produce viable dark matter. This is due to the fact that, in addition to the lightest neutral bound state, cryptons give rise to meta-stable charged bound states. However, these states may still account for the UHECR events. We argue that the uniton, which is an exotic Standard Mod...

  11. A highly stable microchannel heat sink for convective boiling

    International Nuclear Information System (INIS)

    Lu, Chun Ting; Pan Chin

    2009-01-01

    To develop a highly stable two-phase microchannel heat sink, we experimented with convective boiling in diverging, parallel microchannels with different distributions of laser-etched artificial nucleation sites. Each microchannel had a mean hydraulic diameter of 120 µm. The two-phase flow visualization and the magnitudes of pressure drop and inlet temperature oscillations under boiling conditions demonstrated clearly the merits of using artificial nucleation sites to further stabilize the flow boiling in diverging, parallel microchannels. The stability map showed the plane of subcooling number versus phase change number. It illustrated that diverging, parallel microchannels with artificial nucleation cavities have a much wider stable region than parallel microchannels with uniform cross-sections or diverging, parallel microchannels without artificial nucleation cavities. In addition, the results revealed that the design with cavities distributed uniformly along the downstream half of the channel presented the best stability performance among the three distributions of nucleation sites. This particular design can be regarded as a highly stable microchannel heat sink for convective boiling

  12. Meiotically stable natural epialleles of Sadhu, a novel Arabidopsis retroposon.

    Directory of Open Access Journals (Sweden)

    Sanjida H Rangwala

    2006-03-01

    Full Text Available Epigenetic variation is a potential source of genomic and phenotypic variation among different individuals in a population, and among different varieties within a species. We used a two-tiered approach to identify naturally occurring epigenetic alleles in the flowering plant Arabidopsis: a primary screen for transcript level polymorphisms among three strains (Col, Cvi, Ler, followed by a secondary screen for epigenetic alleles. Here, we describe the identification of stable, meiotically transmissible epigenetic alleles that correspond to one member of a previously uncharacterized non-LTR retroposon family, which we have designated Sadhu. The pericentromeric At2g10410 element is highly expressed in strain Col, but silenced in Ler and 18 other strains surveyed. Transcription of this locus is inversely correlated with cytosine methylation and both the expression and DNA methylation states map in a Mendelian manner to stable cis-acting variation. The silent Ler allele can be converted by the epigenetic modifier mutation ddm1 to a meiotically stable expressing allele with an identical primary nucleotide sequence, demonstrating that the variation responsible for transcript level polymorphism among Arabidopsis strains is epigenetic. We extended our characterization of the Sadhu family members and show that different elements are subject to both genetic and epigenetic variation in natural populations. These findings support the view that an important component of natural variation in retroelements is epigenetic.

  13. On the joint statistics of stable random processes

    International Nuclear Information System (INIS)

    Hopcraft, K I; Jakeman, E

    2011-01-01

    A utilitarian continuous bi-variate random process whose first-order probability density function is a stable random variable is constructed. Results paralleling some of those familiar from the theory of Gaussian noise are derived. In addition to the joint-probability density for the process, these include fractional moments and structure functions. Although the correlation functions for stable processes other than Gaussian do not exist, we show that there is coherence between values adopted by the process at different times, which identifies a characteristic evolution with time. The distribution of the derivative of the process, and the joint-density function of the value of the process and its derivative measured at the same time are evaluated. These enable properties to be calculated analytically such as level crossing statistics and those related to the random telegraph wave. When the stable process is fractal, the proportion of time it spends at zero is finite and some properties of this quantity are evaluated, an optical interpretation for which is provided. (paper)

  14. NEBIVOLOL IN TREATMENT OF STABLE EXERTIONAL ANGINA PECTORIS

    Directory of Open Access Journals (Sweden)

    Y. V. Gavrilov

    2015-12-01

    Full Text Available Aim. To evaluate antianginal and antiischemic efficiency of nebivolol in patients with stable angina pectoris.Material and methods. 100 patients with ischemic heart disease showing stable exertional angina pectoris and having no contraindications to beta-blockers were studied. After 5-7 days of control period 50 randomly selected patients began to take nebivolol in initial dose of 5mg once daily and 50 patients started to take metoprolol in initial dose of 50 mg twice daily. Duration of treatment was 8 weeks. Efficiency of treatment was assessed according to the results of control treadmill assessment and control daily ECG monitoring.Results. 56-day therapy with nebivolol at a dose of 7,5 mg per day results in increase in duration of treadmill test before angina or ST depression (p<0.05. Antianginal and antiischemic effect of nebivolol 7.5 mg once daily is rather similar with that of metoprolol in average daily dose of 175 mg. Nebivolol compared to metoprolol significantly (p<0.05 more effectively reduces the number of silent myocardial ischemia.Conclusion. Nebivolol is an efficient antianginal and antiischemic drug for patients with stable exertional angina pectoris.

  15. The separation of stable water-in-oil emulsions

    International Nuclear Information System (INIS)

    Velicogna, D.; Koundakjiian, A.; Beausejour, I.

    1993-01-01

    Stable oil-in-water emulsions are a major problem in the recovery of spilled oils. Such emulsions can contain as little as 10% oil and can have properties very different from the original oils, making their storage and disposal difficult. These problems have led to experiments testing the feasibility of a process for separating these stable emulsions into dischargeable water and reusable oil. The technique investigated involves use of a recyclable solvent to remove the oil and subsequent distillation and/or membrane treatment to recover the oil and recycle the solvent. Results of preliminary tests show that stable water-in-oil emulsions can be separated quite readily with a regenerated solvent system. The only products of these systems are oil, which can be sent to a refinery, and dischargeable water. The recycled solvent can be used many times without any significant decrease in separation efficiency. In order to enhance the throughput of the system, a solvent vapor stripping method was invented. This stripping method also improves the quality of the products and the recycled solvent. Membrane methods can be used as a post-treatment for the produced water in order to achieve more adequate compliance with discharge limits. 4 refs., 3 figs., 5 tabs

  16. Stable cycling of double-walled silicon nanotube battery anodes through solid–electrolyte interphase control

    KAUST Repository

    Wu, Hui

    2012-03-25

    Although the performance of lithium ion-batteries continues to improve, their energy density and cycle life remain insufficient for applications in consumer electronics, transport and large-scale renewable energy storage 1-5. Silicon has a large charge storage capacity and this makes it an attractive anode material, but pulverization during cycling and an unstable solid-electrolyte interphase has limited the cycle life of silicon anodes to hundreds of cycles 6-11. Here, we show that anodes consisting of an active silicon nanotube surrounded by an ion-permeable silicon oxide shell can cycle over 6,000 times in half cells while retaining more than 85% of their initial capacity. The outer surface of the silicon nanotube is prevented from expansion by the oxide shell, and the expanding inner surface is not exposed to the electrolyte, resulting in a stable solid-electrolyte interphase. Batteries containing these double-walled silicon nanotube anodes exhibit charge capacities approximately eight times larger than conventional carbon anodes and charging rates of up to 20C (a rate of 1C corresponds to complete charge or discharge in one hour). © 2012 Macmillan Publishers Limited. All rights reserved.

  17. Effect of surface wettability caused by radiation induced surface activation on leidenfrost condition

    International Nuclear Information System (INIS)

    Takamasa, T.; Hazuku, T.; Tamura, N.; Okamoto, K.; Mishima, K.; Furuya, M.

    2003-01-01

    Improving the limit of boiling heat transfer or critical heat flux requires that the cooling liquid can contact the heating surface, or a high-wettability, highly hydrophilic heating surface, even if a vapor bubble layer is generated on the surface. From this basis, we investigated surface wettability and Leidenfrost condition using metal oxides irradiated by γ-rays. In our previous study, contact angle, an indicator of macroscopic wettability, of a water droplet on metal oxide at room temperature was measured by image processing of the images obtained by a CCD video camera. The results showed that the surface wettability on metal oxide pieces of titanium, Zircaloy No. 4, SUS-304, and copper was improved significantly by the Radiation Induced Surface Activation (RISA) phenomenon. To delineate the effect of Radiation Induced Surface Activation (RISA) on heat transferring phenomena, the Leidenfrost condition and quenching of metal oxides irradiated by γ-rays were investigated. In the Leidenfrost experiment, when the temperature of the heating surface reached the wetting limit temperature, water-solid contact vanished because a stable vapor film existed between the droplet and the metal surface; i.e., a Leidenfrost condition obtained. The wetting limit temperature increased with integrated irradiation dose. After irradiation, the wet length and the duration of contact increased, and the contact angle decreased. In the quenching test, high surface wettability, or a highly hydrophilic condition, of a simulated fuel rod made of SUS was achieved, and the quenching velocities were increased up to 20-30% after 300 kGy 60Co γ-ray irradiation

  18. Effect of surface wettability caused by radiation induced surface activation on leidenfrost condition

    Energy Technology Data Exchange (ETDEWEB)

    Takamasa, T.; Hazuku, T.; Tamura, N.; Okamoto, K. [Tokyo Univ., Tokyo (Japan); Mishima, K. [Kyoto Univ., Kyoto (Japan); Furuya, M. [Central Research Institute of Electric Power Industry, Tokyo (Japan)

    2003-07-01

    Improving the limit of boiling heat transfer or critical heat flux requires that the cooling liquid can contact the heating surface, or a high-wettability, highly hydrophilic heating surface, even if a vapor bubble layer is generated on the surface. From this basis, we investigated surface wettability and Leidenfrost condition using metal oxides irradiated by {gamma}-rays. In our previous study, contact angle, an indicator of macroscopic wettability, of a water droplet on metal oxide at room temperature was measured by image processing of the images obtained by a CCD video camera. The results showed that the surface wettability on metal oxide pieces of titanium, Zircaloy No. 4, SUS-304, and copper was improved significantly by the Radiation Induced Surface Activation (RISA) phenomenon. To delineate the effect of Radiation Induced Surface Activation (RISA) on heat transferring phenomena, the Leidenfrost condition and quenching of metal oxides irradiated by {gamma}-rays were investigated. In the Leidenfrost experiment, when the temperature of the heating surface reached the wetting limit temperature, water-solid contact vanished because a stable vapor film existed between the droplet and the metal surface; i.e., a Leidenfrost condition obtained. The wetting limit temperature increased with integrated irradiation dose. After irradiation, the wet length and the duration of contact increased, and the contact angle decreased. In the quenching test, high surface wettability, or a highly hydrophilic condition, of a simulated fuel rod made of SUS was achieved, and the quenching velocities were increased up to 20-30% after 300 kGy 60Co {gamma}-ray irradiation.

  19. Stable Protein-Repellent Zwitterionic Polymer Brushes Grafted from Silicon Nitride

    NARCIS (Netherlands)

    Nguyen, A.T.; Baggerman, J.; Paulusse, J.M.J.; Rijn, van C.J.M.; Zuilhof, H.

    2011-01-01

    Zwitterionic poly(sulfobetaine acrylamide) (SBMAA) brushes were grafted from silicon-rich silicon nitride (SixN4, x > 3) surfaces by atom transfer radical polymerization (ATRP) and studied in protein adsorption experiments. To this aim ATRP initiators were immobilized onto SixN4 through stable

  20. Stable Protein-Repellent Zwitterionic Polymer Brushes Grafted from Silicon Nitride

    NARCIS (Netherlands)

    Nguyen, Ai T.; Baggerman, Jacob; Paulusse, Jos Marie Johannes; van Rijn, Cees J.M.; Zuilhof, Han

    2011-01-01

    Zwitterionic poly(sulfobetaine acrylamide) (SBMAA) brushes were grafted from silicon-rich silicon nitride (SixN4, x > 3) surfaces by atom transfer radical polymerization (ATRP) and studied in protein adsorption experiments. To this aim ATRP initiators were immobilized onto SixN4 through stable Si−C