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Sample records for 1-100 road boron

  1. Boron

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Boron is an essential micronutrient element required for plant growth. Boron deficiency is wide-spread in crop plants throughout the world especially in coarse-textured soils in humid areas. Boron toxicity can also occur, especially in arid regions under irrigation. Plants respond directly to the...

  2. Boron

    MedlinePlus

    ... form of boron, inside the vagina to treat yeast infections. People also apply boric acid to the ... acid, used inside the vagina, can successfully treat yeast infections (candidiasis), including infections that do not seem ...

  3. SANCscope—v.1.00

    NASA Astrophysics Data System (ADS)

    Andonov, A.; Arbuzov, A.; Bardin, D.; Bondarenko, S.; Christova, P.; Kalinovskaya, L.; Nanava, G.; von Schlippe, W.

    2006-03-01

    In this article we have summarized the status of the system SANC version 1.00. We have implemented theoretical predictions for many high energy interactions of fundamental particles at the one-loop precision level for up to 4-particle processes. In the present part of our SANC description we place emphasis on an extensive discussion of an important first step of calculations of the one-loop amplitudes of 3- and 4-particle processes in QED, QCD and EW theories. Program summaryTitle of program:SANC Catalogue identifier: ADXK_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADXK_v1_0 Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Designed for: platforms on which Java and FORM3 are available Tested on: Intel-based PC's Operating systems: Linux, Windows Programming languages used: Java, FORM3, PERL, FORTRAN Memory required to execute with typical data: 10 Mb No. of bytes in distributed program, including test data, etc.: 3 658 844 No. of bits in a word: 32 No. of processors used: 1 on SANC server, 1 on SANC client Distribution format: tar.gz Nature of physical problem: Automatic calculation of pseudo- and realistic observables for various processes and decays in the Standard Model of Electroweak interactions, QCD and QED at one-loop precision level. Form factors and helicity amplitudes free of UV divergences are produced. For exclusion of IR singularities the soft photon emission is included. Method of solution: Numerical computation of analytical formulae of form factors and helicity amplitudes. For simulation of two fermion radiative decays of Standard Model bosons (W,Z) and the Higgs boson a Monte Carlo technique is used. Restrictions on the complexity: In the current version of SANC there are 3 and 4 particle processes and decays available at one-loop precision level. Typical running time: The running time depends on the selected process. For instance, the symbolic calculation of form factors (with precomputed building blocks) of Bhabha scattering in the Standard Model takes about 15 s, helicity amplitudes—about 30 s, and bremsstrahlung—10 s. The numerical computation of cross-section for this process takes about 5 s (CPU 3 GHz IP4, RAM 512 Mb, L2 1024 KB).

  4. Boron deposition from fused salts. Final report

    SciTech Connect

    Smith, M.L.

    1980-08-01

    A partial evaluation of the feasibility of a process to electrodeposit pure coherent coatings of elemental boron from molten fluorides has been performed. The deposit produced was powdery and acicular, unless the fluoride melt was purified to have very low oxygen concentration. When the oxygen activity was reduced in the melt by addition of crystalline elemental boron, dense, amorphous boron deposit was produced. The boron deposits produced had cracks but were otherwise pure and dense and ranged up to 0.35 mm thick. Information derived during this project suggests that similar deposits might be obtained crack-free up to 1.00 mm thick by process modifications and improvements.

  5. Boron supercapacitors

    SciTech Connect

    Zhan, Cheng; Zhang, Pengfei; Dai, Sheng; Jiang, De -en

    2016-11-16

    Supercapacitors based on the electric double-layer mechanism use porous carbons or graphene as electrodes. To move beyond this paradigm, we propose boron supercapacitors to leverage two-dimensional (2D) boron sheets’ metallicity and low weight. Six 2D boron sheets from both previous theoretical design and experimental growth are chosen as test electrodes. By applying joint density functional theory (JDFT) to the electrode–electrolyte system, we examine how the 2D boron sheets charge up against applied potential. JDFT predicts that these 2D boron sheets exhibit specific capacitance on the order of 400 F/g, about four times that of graphene. As a result, our work suggests that 2D boron sheets are promising electrodes for supercapacitor applications.

  6. Boron cosmochemistry

    NASA Technical Reports Server (NTRS)

    Curtis, D. B.; Gladney, E. S.

    1985-01-01

    The abundances of boron, silicon, sulfur, and sodium were determined in 50 pieces of 28 chondritic meteorites. Boron abundances are found to define compositionally distinct domains within type C2M carbonaceous chondrites and petrologic type 5 and 6 ordinary chondrites. These domains may manifest the redistribution of boron within meteorites in response to low-temperature hydrous processes in C2M chondrites and high-temperature metamorphic processes in high petrologic type ordinary chondrites. Assuming that the redistribution was limited to regions comparable in size to the mass of the available meteorites, the boron abundance in unaltered material is determined. The depletion factors for boron in chondritic subgroups correlate with those for sulfur in the same subgroups. This correlation indicates that boron, like sulfur, is a moderately volatile element with a condensation temperature between 400 and 900 K.

  7. Boron supercapacitors

    DOE PAGES

    Zhan, Cheng; Zhang, Pengfei; Dai, Sheng; ...

    2016-11-16

    Supercapacitors based on the electric double-layer mechanism use porous carbons or graphene as electrodes. To move beyond this paradigm, we propose boron supercapacitors to leverage two-dimensional (2D) boron sheets’ metallicity and low weight. Six 2D boron sheets from both previous theoretical design and experimental growth are chosen as test electrodes. By applying joint density functional theory (JDFT) to the electrode–electrolyte system, we examine how the 2D boron sheets charge up against applied potential. JDFT predicts that these 2D boron sheets exhibit specific capacitance on the order of 400 F/g, about four times that of graphene. As a result, our workmore » suggests that 2D boron sheets are promising electrodes for supercapacitor applications.« less

  8. Boron reclamation

    SciTech Connect

    Smith, R.M.

    1980-07-01

    A process to recover high purity /sup 10/B enriched crystalline boron powder from a polymeric matrix was developed on a laboratory basis and ultimately scaled up to production capacity. The process is based on controlled pyrolysis of boron-filled scrap followed by an acid leach and dry sieving operation to return the powder to the required purity and particle size specifications. Typically, the recovery rate of the crystalline powder is in excess of 98.5 percent, and some of the remaining boron is recovered in the form of boric acid. The minimum purity requirement of the recovered product is 98.6 percent total boron.

  9. 2 CFR 1.100 - Content of this title.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 2 Grants and Agreements 1 2013-01-01 2013-01-01 false Content of this title. 1.100 Section 1.100 Grants and Agreements Office of Management and Budget Guidance for Grants and Agreements ABOUT TITLE 2 OF THE CODE OF FEDERAL REGULATIONS AND SUBTITLE A Introduction to Title 2 of the CFR § 1.100 Content...

  10. 2 CFR 1.100 - Content of this title.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 2 Grants and Agreements 1 2014-01-01 2014-01-01 false Content of this title. 1.100 Section 1.100 Grants and Agreements Office of Management and Budget Guidance for Grants and Agreements ABOUT TITLE 2 OF THE CODE OF FEDERAL REGULATIONS AND SUBTITLE A Introduction to Title 2 of the CFR § 1.100 Content...

  11. 2 CFR 1.100 - Content of this title.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 2 Grants and Agreements 1 2012-01-01 2012-01-01 false Content of this title. 1.100 Section 1.100 Grants and Agreements Office of Management and Budget Guidance for Grants and Agreements ABOUT TITLE 2 OF THE CODE OF FEDERAL REGULATIONS AND SUBTITLE A Introduction to Title 2 of the CFR § 1.100 Content...

  12. 2 CFR 1.100 - Content of this title.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 2 Grants and Agreements 1 2011-01-01 2011-01-01 false Content of this title. 1.100 Section 1.100 Grants and Agreements Office of Management and Budget Guidance for Grants and Agreements ABOUT TITLE 2 OF THE CODE OF FEDERAL REGULATIONS AND SUBTITLE A Introduction to Title 2 of the CFR § 1.100 Content...

  13. 2 CFR 1.100 - Content of this title.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 2 Grants and Agreements 1 2010-01-01 2010-01-01 false Content of this title. 1.100 Section 1.100 Grants and Agreements ABOUT TITLE 2 OF THE CODE OF FEDERAL REGULATIONS AND SUBTITLE A Introduction to Title 2 of the CFR § 1.100 Content of this title. This title contains— (a) Office of Management...

  14. Electroextraction of boron from boron carbide scrap

    SciTech Connect

    Jain, Ashish; Anthonysamy, S.; Ghosh, C.; Ravindran, T.R.; Divakar, R.; Mohandas, E.

    2013-10-15

    Studies were carried out to extract elemental boron from boron carbide scrap. The physicochemical nature of boron obtained through this process was examined by characterizing its chemical purity, specific surface area, size distribution of particles and X-ray crystallite size. The microstructural characteristics of the extracted boron powder were analyzed by using scanning electron microscopy and transmission electron microscopy. Raman spectroscopic examination of boron powder was also carried out to determine its crystalline form. Oxygen and carbon were found to be the major impurities in boron. Boron powder of purity ∼ 92 wt. % could be produced by the electroextraction process developed in this study. Optimized method could be used for the recovery of enriched boron ({sup 10}B > 20 at. %) from boron carbide scrap generated during the production of boron carbide. - Highlights: • Recovery of {sup 10}B from nuclear grade boron carbide scrap • Development of process flow sheet • Physicochemical characterization of electroextracted boron • Microscopic examination of electroextracted boron.

  15. 41 CFR 109-1.100-51 - Definitions and acronyms.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 41 Public Contracts and Property Management 3 2014-01-01 2014-01-01 false Definitions and acronyms. 109-1.100-51 Section 109-1.100-51 Public Contracts and Property Management Federal Property Management Regulations System (Continued) DEPARTMENT OF ENERGY PROPERTY MANAGEMENT REGULATIONS GENERAL 1-INTRODUCTION...

  16. 12 CFR 1.100 - Indirect general obligations.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... of 12 U.S.C. 24 (Seventh), if a party possessing general powers of taxation unconditionally promises... 12 Banks and Banking 1 2013-01-01 2013-01-01 false Indirect general obligations. 1.100 Section 1.100 Banks and Banking COMPTROLLER OF THE CURRENCY, DEPARTMENT OF THE TREASURY INVESTMENT...

  17. 12 CFR 1.100 - Indirect general obligations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... of 12 U.S.C. 24 (Seventh), if a party possessing general powers of taxation unconditionally promises... 12 Banks and Banking 1 2011-01-01 2011-01-01 false Indirect general obligations. 1.100 Section 1.100 Banks and Banking COMPTROLLER OF THE CURRENCY, DEPARTMENT OF THE TREASURY INVESTMENT...

  18. 41 CFR 109-1.100-51 - Definitions and acronyms.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Technologies List OCRM: Office of Contract and Resource Management OPMO: Organizational Property Management... 41 Public Contracts and Property Management 3 2011-01-01 2011-01-01 false Definitions and acronyms. 109-1.100-51 Section 109-1.100-51 Public Contracts and Property Management Federal Property...

  19. 41 CFR 109-1.100-51 - Definitions and acronyms.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Technologies List OCRM: Office of Contract and Resource Management OPMO: Organizational Property Management... 41 Public Contracts and Property Management 3 2012-01-01 2012-01-01 false Definitions and acronyms. 109-1.100-51 Section 109-1.100-51 Public Contracts and Property Management Federal Property...

  20. Direct current sputtering of boron from boron/boron mixtures

    DOEpatents

    Timberlake, J.R.; Manos, D.; Nartowitz, E.

    1994-12-13

    A method for coating a substrate with boron by sputtering includes lowering the electrical resistance of a boron-containing rod to allow electrical conduction in the rod; placing the boron-containing rod inside a vacuum chamber containing substrate material to be coated; applying an electrical potential between the boron target material and the vacuum chamber; countering a current avalanche that commences when the conduction heating rate exceeds the cooling rate, and until a steady equilibrium heating current is reached; and, coating the substrate material with boron by sputtering from the boron-containing rod. 2 figures.

  1. Digital geologic map of part of the Thompson Falls 1:100,000 quadrangle, Idaho

    USGS Publications Warehouse

    Lewis, Reed S.; Derkey, Pamela D.

    1999-01-01

    The geology of the Thompson Falls 1:100,000 quadrangle, Idaho was compiled by Reed S. Lewis in 1997 onto a 1:100,000-scale greenline mylar of the topographic base map for input into a geographic information system (GIS). The resulting digital geologic map GIS can be queried in many ways to produce a variety of geologic maps. Digital base map data files (topography, roads, towns, rivers and lakes, etc.) are not included: they may be obtained from a variety of commercial and government sources. This database is not meant to be used or displayed at any scale larger than 1:100,000 (e.g., 1:62,500 or 1:24,000). The map area is located in north Idaho. This open-file report describes the geologic map units, the methods used to convert the geologic map data into a digital format, the Arc/Info GIS file structures and relationships, and explains how to download the digital files from the U.S. Geological Survey public access World Wide Web site on the Internet.

  2. 41 CFR 101-1.100 - Scope of subpart.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Management Regulations System: its content, types, publication, authority, applicability, numbering... System FEDERAL PROPERTY MANAGEMENT REGULATIONS GENERAL 1-INTRODUCTION 1.1-Regulation System § 101-1.100... 41 Public Contracts and Property Management 2 2011-07-01 2007-07-01 true Scope of subpart....

  3. 41 CFR 101-1.100 - Scope of subpart.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Management Regulations System: its content, types, publication, authority, applicability, numbering... System FEDERAL PROPERTY MANAGEMENT REGULATIONS GENERAL 1-INTRODUCTION 1.1-Regulation System § 101-1.100... 41 Public Contracts and Property Management 2 2013-07-01 2012-07-01 true Scope of subpart....

  4. 41 CFR 101-1.100 - Scope of subpart.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Management Regulations System: its content, types, publication, authority, applicability, numbering... System FEDERAL PROPERTY MANAGEMENT REGULATIONS GENERAL 1-INTRODUCTION 1.1-Regulation System § 101-1.100... 41 Public Contracts and Property Management 2 2010-07-01 2010-07-01 true Scope of subpart....

  5. 41 CFR 101-1.100 - Scope of subpart.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Management Regulations System: its content, types, publication, authority, applicability, numbering... System FEDERAL PROPERTY MANAGEMENT REGULATIONS GENERAL 1-INTRODUCTION 1.1-Regulation System § 101-1.100... 41 Public Contracts and Property Management 2 2014-07-01 2012-07-01 true Scope of subpart....

  6. 41 CFR 109-1.100-50 - Scope of subpart.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Regulations System (Continued) DEPARTMENT OF ENERGY PROPERTY MANAGEMENT REGULATIONS GENERAL 1-INTRODUCTION 1.1-Regulation System § 109-1.100-50 Scope of subpart. This subpart sets forth the Department of Energy (DOE..., regulations, and procedures that implement and supplement the Federal Property Management...

  7. Crystalline boron nitride aerogels

    DOEpatents

    Zettl, Alexander K.; Rousseas, Michael; Goldstein, Anna P.; Mickelson, William; Worsley, Marcus A.; Woo, Leta

    2017-04-04

    This disclosure provides methods and materials related to boron nitride aerogels. In one aspect, a material comprises an aerogel comprising boron nitride. The boron nitride has an ordered crystalline structure. The ordered crystalline structure may include atomic layers of hexagonal boron nitride lying on top of one another, with atoms contained in a first layer being superimposed on atoms contained in a second layer.

  8. Boron nitride composites

    DOEpatents

    Kuntz, Joshua D.; Ellsworth, German F.; Swenson, Fritz J.; Allen, Patrick G.

    2017-02-21

    According to one embodiment, a composite product includes: a matrix material including hexagonal boron nitride and one or more borate binders; and a plurality of cubic boron nitride particles dispersed in the matrix material. According to another embodiment, a composite product includes: a matrix material including hexagonal boron nitride and amorphous boron nitride; and a plurality of cubic boron nitride particles dispersed in the matrix material.

  9. Boron Nitride Nanotubes

    NASA Technical Reports Server (NTRS)

    Smith, Michael W. (Inventor); Jordan, Kevin (Inventor); Park, Cheol (Inventor)

    2012-01-01

    Boron nitride nanotubes are prepared by a process which includes: (a) creating a source of boron vapor; (b) mixing the boron vapor with nitrogen gas so that a mixture of boron vapor and nitrogen gas is present at a nucleation site, which is a surface, the nitrogen gas being provided at a pressure elevated above atmospheric, e.g., from greater than about 2 atmospheres up to about 250 atmospheres; and (c) harvesting boron nitride nanotubes, which are formed at the nucleation site.

  10. Boron nitride nanotubes

    DOEpatents

    Smith, Michael W [Newport News, VA; Jordan, Kevin [Newport News, VA; Park, Cheol [Yorktown, VA

    2012-06-06

    Boron nitride nanotubes are prepared by a process which includes: (a) creating a source of boron vapor; (b) mixing the boron vapor with nitrogen gas so that a mixture of boron vapor and nitrogen gas is present at a nucleation site, which is a surface, the nitrogen gas being provided at a pressure elevated above atmospheric, e.g., from greater than about 2 atmospheres up to about 250 atmospheres; and (c) harvesting boron nitride nanotubes, which are formed at the nucleation site.

  11. Methods of forming boron nitride

    DOEpatents

    Trowbridge, Tammy L; Wertsching, Alan K; Pinhero, Patrick J; Crandall, David L

    2015-03-03

    A method of forming a boron nitride. The method comprises contacting a metal article with a monomeric boron-nitrogen compound and converting the monomeric boron-nitrogen compound to a boron nitride. The boron nitride is formed on the same or a different metal article. The monomeric boron-nitrogen compound is borazine, cycloborazane, trimethylcycloborazane, polyborazylene, B-vinylborazine, poly(B-vinylborazine), or combinations thereof. The monomeric boron-nitrogen compound is polymerized to form the boron nitride by exposure to a temperature greater than approximately 100.degree. C. The boron nitride is amorphous boron nitride, hexagonal boron nitride, rhombohedral boron nitride, turbostratic boron nitride, wurzite boron nitride, combinations thereof, or boron nitride and carbon. A method of conditioning a ballistic weapon and a metal article coated with the monomeric boron-nitrogen compound are also disclosed.

  12. Boron nitride converted carbon fiber

    SciTech Connect

    Rousseas, Michael; Mickelson, William; Zettl, Alexander K.

    2016-04-05

    This disclosure provides systems, methods, and apparatus related to boron nitride converted carbon fiber. In one aspect, a method may include the operations of providing boron oxide and carbon fiber, heating the boron oxide to melt the boron oxide and heating the carbon fiber, mixing a nitrogen-containing gas with boron oxide vapor from molten boron oxide, and converting at least a portion of the carbon fiber to boron nitride.

  13. Digital Geologic Map of the Wallace 1:100,000 Quadrangle, Idaho

    USGS Publications Warehouse

    Lewis, Reed S.; Burmester, Russell F.; McFaddan, Mark D.; Derkey, Pamela D.; Oblad, Jon R.

    1999-01-01

    The geology of the Wallace 1:100,000 quadrangle, Idaho was compiled by Reed S. Lewis in 1997 primarily from published materials including 1983 data from Foster, Harrison's unpublished mapping done from 1975 to 1985, Hietenan's 1963, 1967, 1968, and 1984 mapping, Hobbs and others 1965 mapping, and Vance's 1981 mapping, supplemented by eight weeks of field mapping by Reed S. Lewis, Russell F. Burmester, and Mark D. McFaddan in 1997 and 1998. This geologic map information was inked onto a 1:100,000-scale greenline mylar of the topographic base map for input into a geographic information system (GIS). The resulting digital geologic map GIS can be queried in many ways to produce a variety of geologic maps. Digital base map data files (topography, roads, towns, rivers and lakes, etc.) are not included: they may be obtained from a variety of commercial and government sources. This database is not meant to be used or displayed at any scale larger than 1:100,000 (e.g., 1:62,500 or 1:24,000). The map area is located in north Idaho. The primary sources of map data are shown in figure 2 and additional sources are shown in figure 3. This open-file report describes the geologic map units, the methods used to convert the geologic map data into a digital format, the Arc/Info GIS file structures and relationships, and explains how to download the digital files from the U.S. Geological Survey public access World Wide Web site on the Internet. Mapping and compilation was completed by the Idaho Geological Survey under contract with the U.S. Geological Survey (USGS) office in Spokane, Washington. The authors would like to acknowledge the help of the following field assistants: Josh Goodman, Yvonne Issak, Jeremy Johnson and Kevin Myer. Don Winston provided help with our ongoing study of Belt stratigraphy, and Tom Frost assisted with logistical problems and sample collection. Manuscript reviews by Steve Box, Tom Frost, and Brian White are greatly appreciated. We wish to thank Karen S

  14. Microstructure Analysis of Boron Nanotubes

    DTIC Science & Technology

    2012-05-01

    boron nitride nanotube and nanoparticles in thin film boron nitride prepared by CVD method. Electron micrographs show single...walled nanotubes containing these nonoparticles. The electron diffraction pattern confirms this boron nitride has a hexagonal crystal structure. 15... boron nitride thin film CONCLUSIONS The boron evaporated thin film revealed a large number of nanotubes and nanoparticles. These nanotubes are 25

  15. Fabrication of boron articles

    DOEpatents

    Benton, Samuel T.

    1976-01-01

    This invention is directed to the fabrication of boron articles by a powder metallurgical method wherein the articles are of a density close to the theoretical density of boron and are essentially crackfree. The method comprises the steps of admixing 1 to 10 weight percent carbon powder with amorphous boron powder, cold pressing the mixture and then hot pressing the cold pressed compact into the desired article. The addition of the carbon to the mixture provides a pressing aid for inhibiting the cracking of the hot pressed article and is of a concentration less than that which would cause the articles to possess significant concentrations of boron carbide.

  16. 41 CFR 302-1.100 - What is a comprehensive, automated relocation management system?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Agency Data for Employee Relocation § 302-1.100 What is a comprehensive, automated relocation management... 41 Public Contracts and Property Management 4 2011-07-01 2011-07-01 false What is a comprehensive, automated relocation management system? 302-1.100 Section 302-1.100 Public Contracts and Property...

  17. 41 CFR 302-1.100 - What is a comprehensive, automated relocation management system?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Agency Data for Employee Relocation § 302-1.100 What is a comprehensive, automated relocation management... 41 Public Contracts and Property Management 4 2012-07-01 2012-07-01 false What is a comprehensive, automated relocation management system? 302-1.100 Section 302-1.100 Public Contracts and Property...

  18. 41 CFR 302-1.100 - What is a comprehensive, automated relocation management system?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Agency Data for Employee Relocation § 302-1.100 What is a comprehensive, automated relocation management... 41 Public Contracts and Property Management 4 2014-07-01 2014-07-01 false What is a comprehensive, automated relocation management system? 302-1.100 Section 302-1.100 Public Contracts and Property...

  19. 41 CFR 302-1.100 - What is a comprehensive, automated relocation management system?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Agency Data for Employee Relocation § 302-1.100 What is a comprehensive, automated relocation management... 41 Public Contracts and Property Management 4 2013-07-01 2012-07-01 true What is a comprehensive, automated relocation management system? 302-1.100 Section 302-1.100 Public Contracts and Property...

  20. The structure of boron in boron fibres

    NASA Technical Reports Server (NTRS)

    Bhardwaj, J.; Krawitz, A. D.

    1983-01-01

    The structure of noncrystalline, chemically vapour-deposited boron fibres was investigated by computer modelling the experimentally obtained X-ray diffraction patterns. The diffraction patterns from the models were computed using the Debye scattering equation. The modelling was done utilizing the minimum nearest-neighbour distance, the density of the model, and the broadening and relative intensity of the various peaks as boundary conditions. The results suggest that the fibres consist of a continuous network of randomly oriented regions of local atomic order, about 2 nm in diameter, containing boron atoms arranged in icosahedra. Approximately half of these regions have a tetragonal structure and the remaining half a distorted rhombohedral structure. The model also indicates the presence of many partial icosahedra and loose atoms not associated with any icosahedra. The partial icosahedra and loose atoms indicated in the present model are in agreement with the relaxing sub-units which have been suggested to explain the anelastic behavior of fibre boron and the loosely bound boron atoms which have been postulated to explain the strengthening mechanism in boron fibres during thermal treatment.

  1. Magnetron sputtered boron films

    DOEpatents

    Makowiecki, D.M.; Jankowski, A.F.

    1998-06-16

    A method is described for the production of thin boron and titanium/boron films by magnetron sputter deposition. The amorphous boron films contain no morphological growth features, unlike those found when thin films are prepared by various physical vapor deposition processes. Magnetron sputter deposition method requires the use of a high density crystalline boron sputter target which is prepared by hot isostatic pressing. Thin boron films prepared by this method are useful for producing hardened surfaces, surfacing machine tools, etc. and for ultra-thin band pass filters as well as the low Z element in low Z/high Z optical components, such as mirrors which enhance reflectivity from grazing to normal incidence. 8 figs.

  2. Magnetron sputtered boron films

    DOEpatents

    Makowiecki, Daniel M.; Jankowski, Alan F.

    1998-01-01

    A method is described for the production of thin boron and titanium/boron films by magnetron sputter deposition. The amorphous boron films contain no morphological growth features, unlike those found when thin films are prepared by various physical vapor deposition processes. Magnetron sputter deposition method requires the use of a high density crystalline boron sputter target which is prepared by hot isostatic pressing. Thin boron films prepared by this method are useful for producing hardened surfaces, surfacing machine tools, etc. and for ultra-thin band pass filters as well as the low Z element in low Z/high Z optical components, such as mirrors which enhance reflectivity from grazing to normal incidence.

  3. Distributed road assessment system

    DOEpatents

    Beer, N. Reginald; Paglieroni, David W

    2014-03-25

    A system that detects damage on or below the surface of a paved structure or pavement is provided. A distributed road assessment system includes road assessment pods and a road assessment server. Each road assessment pod includes a ground-penetrating radar antenna array and a detection system that detects road damage from the return signals as the vehicle on which the pod is mounted travels down a road. Each road assessment pod transmits to the road assessment server occurrence information describing each occurrence of road damage that is newly detected on a current scan of a road. The road assessment server maintains a road damage database of occurrence information describing the previously detected occurrences of road damage. After the road assessment server receives occurrence information for newly detected occurrences of road damage for a portion of a road, the road assessment server determines which newly detected occurrences correspond to which previously detected occurrences of road damage.

  4. Microwave sintering of boron carbide

    DOEpatents

    Blake, R.D.; Katz, J.D.; Petrovic, J.J.; Sheinberg, H.

    1988-06-10

    A method for forming boron carbide into a particular shape and densifying the green boron carbide shape. Boron carbide in powder form is pressed into a green shape and then sintered, using a microwave oven, to obtain a dense boron carbide body. Densities of greater than 95% of theoretical density have been obtained. 1 tab.

  5. Credit PSR. View looks south (180°) across North Base Road ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Credit PSR. View looks south (180°) across North Base Road at foundations for Quarters "A", one arm of which appears at right. Bare earth at extreme left is entrance to parking lot between Quarters "A" and "B" - Edwards Air Force Base, North Base, Officers' Quarters B, North Base Road, Boron, Kern County, CA

  6. Digital geologic map of the Coeur d'Alene 1:100,000 quadrangle, Idaho and Montana

    USGS Publications Warehouse

    digital compilation by Munts, Steven R.

    2000-01-01

    Between 1961 and 1969, Alan Griggs and others conducted fieldwork to prepare a geologic map of the Spokane 1:250,000 map (Griggs, 1973). Their field observations were posted on paper copies of 15-minute quadrangle maps. In 1999, the USGS contracted with the Idaho Geological Survey to prepare a digital version of the Coeur d’Alene 1:100,000 quadrangle. To facilitate this work, the USGS obtained the field maps prepared by Griggs and others from the USGS Field Records Library in Denver, Colorado. The Idaho Geological Survey (IGS) digitized these maps and used them in their mapping program. The mapping focused on field checks to resolve problems in poorly known areas and in areas of disagreement between adjoining maps. The IGS is currently in the process of preparing a final digital spatial database for the Coeur d’Alene 1:100,000 quadrangle. However, there was immediate need for a digital version of the geologic map of the Coeur d’Alene 1:100,000 quadrangle and the data from the field sheets along with several other sources were assembled to produce this interim product. This interim product is the digital geologic map of the Coeur d’Alene 1:100,000 quadrangle, Idaho and Montana. It was compiled from the preliminary digital files prepared by the Idaho Geological, and supplemented by data from Griggs (1973) and from digital databases by Bookstrom and others (1999) and Derkey and others (1996). The resulting digital geologic map (GIS) database can be queried in many ways to produce a variety of geologic maps. Digital base map data files (topography, roads, towns, rivers and lakes, etc.) are not included: they may be obtained from a variety of commercial and government sources. This database is not meant to be used or displayed at any scale larger than 1:100,000 (e.g., 1:62,500 or 1:24,000). The digital geologic map graphics (of00-135_map.pdf) that are provided are representations of the digital database. The map area is located in north Idaho. This open

  7. Boron and the kidney.

    PubMed

    Pahl, Madeleine V; Culver, B Dwight; Vaziri, Nosratola D

    2005-10-01

    Boron, the fifth element in the periodic table, is ubiquitous in nature. It is present in food and in surface and ocean waters, and is frequently used in industrial, cosmetic, and medical settings. Exposure to boron and related compounds has been recently implicated as a potential cause of chronic kidney disease in Southeast Asia. This observation prompted the present review of the published data on the effects of acute and chronic exposure to boron on renal function and structure in human beings and in experimental animals.

  8. Innovative method for boron extraction from iron ore containing boron

    NASA Astrophysics Data System (ADS)

    Wang, Guang; Wang, Jing-song; Yu, Xin-yun; Shen, Ying-feng; Zuo, Hai-bin; Xue, Qing-guo

    2016-03-01

    A novel process for boron enrichment and extraction from ludwigite based on iron nugget technology was proposed. The key steps of this novel process, which include boron and iron separation, crystallization of boron-rich slag, and elucidation of the boron extraction behavior of boron-rich slag by acid leaching, were performed at the laboratory. The results indicated that 95.7% of the total boron could be enriched into the slag phase, thereby forming a boron-rich slag during the iron and slag melting separation process. Suanite and kotoite were observed to be the boron-containing crystalline phases, and the boron extraction properties of the boron-rich slag depended on the amounts and grain sizes of these minerals. When the boron-rich slag was slowly cooled to 1100°C, the slag crystallized well and the efficiency of extraction of boron (EEB) of the slag was the highest observed in the present study. The boron extraction property of the slow-cooled boron-rich slag obtained in this study was much better than that of szaibelyite ore under the conditions of 80% of theoretical sulfuric acid amount, leaching time of 30 min, leaching temperature of 40°C, and liquid-to-solid ratio of 8 mL/g.

  9. View east northeast at Test Stand 'A' complex from road, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View east northeast at Test Stand 'A' complex from road, showing Test Stand 'C' test tower in left background (Building 4217/E-18). Curved I-beam labeled '3-ton' is for small traveling hoist. Fuel tanks, propellant lines, and control panels have been removed from tower. - Jet Propulsion Laboratory Edwards Facility, Test Stand A, Edwards Air Force Base, Boron, Kern County, CA

  10. 21. VALVES, GAUGES, AND SEVERAL TYPES OF LIGHTING ALONG ROAD ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    21. VALVES, GAUGES, AND SEVERAL TYPES OF LIGHTING ALONG ROAD AT SOUTH REAR OF TEST STAND 1-A. RP1 TANK FARM IN MIDDLE DISTANCE. Looking northeast. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-A, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

  11. View looking northeast at Test Stand 'A' complex from road, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View looking northeast at Test Stand 'A' complex from road, showing Test Stand 'A' test tower (Building 4202/E-3) in left background, Monitor Building 4203/E-4 in right foreground, and barrier (Building 4216/E-17) behind 4203/E-4. - Jet Propulsion Laboratory Edwards Facility, Test Stand A, Edwards Air Force Base, Boron, Kern County, CA

  12. Direct current sputtering of boron from boron/coron mixtures

    DOEpatents

    Timberlake, John R.; Manos, Dennis; Nartowitz, Ed

    1994-01-01

    A method for coating a substrate with boron by sputtering includes lowering the electrical resistance of a boron-containing rod to allow electrical conduction in the rod; placing the boron-containing rod inside a vacuum chamber containing substrate material to be coated; applying an electrical potential between the boron target material and the vacuum chamber; countering a current avalanche that commences when the conduction heating rate exceeds the cooling rate, and until a steady equilibrium heating current is reached; and, coating the substrate material with boron by sputtering from the boron-containing rod.

  13. Boron-Based Drug Design.

    PubMed

    Ban, Hyun Seung; Nakamura, Hiroyuki

    2015-06-01

    The use of the element boron, which is not generally observed in a living body, possesses a high potential for the discovery of new biological activity in pharmaceutical drug design. In this account, we describe our recent developments in boron-based drug design, including boronic acid containing protein tyrosine kinase inhibitors, proteasome inhibitors, and tubulin polymerization inhibitors, and ortho-carborane-containing proteasome activators, hypoxia-inducible factor 1 inhibitors, and topoisomerase inhibitors. Furthermore, we applied a closo-dodecaborate as a water-soluble moiety as well as a boron-10 source for the design of boron carriers in boron neutron capture therapy, such as boronated porphyrins and boron lipids for a liposomal boron delivery system.

  14. Zeolitic Boron Imidazolate Frameworks**

    PubMed Central

    Zhang, Jian; Wu, Tao; Zhou, Cong; Chen, Shumei; Feng, Pingyun; Bu, Xianhui

    2009-01-01

    From porous AlPO4 to porous BIFs Reported here are a family of crystalline materials based on boron imidazolate frameworks (BIFs). It is demonstrated that the synthetic method, which is based on the crosslinking of various pre-synthesized boron imidazolates by monovalent cations (Li+ and Cu+), is capable of generating a large variety of open frameworks ranging from the 4-connected zeolitic sodalite type to the 3-connected chiral (10,3)-a type. PMID:19241428

  15. Boron nitride composites

    DOEpatents

    Kuntz, Joshua D.; Ellsworth, German F.; Swenson, Fritz J.; Allen, Patrick G.

    2016-02-16

    According to one embodiment, a composite product includes hexagonal boron nitride (hBN), and a plurality of cubic boron nitride (cBN) particles, wherein the plurality of cBN particles are dispersed in a matrix of the hBN. According to another embodiment, a composite product includes a plurality of cBN particles, and one or more borate-containing binders.

  16. Washboard Road

    NASA Astrophysics Data System (ADS)

    McElwaine, Jim; Dalziel, Stuart; Taberlet, Nicolas; Morris, Stephen

    2006-11-01

    The tendency of unpaved road surfaces to develop lateral ripples (``washboard'' or ``corrugated'' road) is annoyingly familiar to drivers on dry gravel roads. Similar ripples are well known on railroad tracks and many other rolling or sliding, load bearing surfaces. Our approach combined laboratory experiments, soft-particle direct numerical simulations and simple nonlinear dynamics models. The experiment consisted of a rotating table 60 cm in radius with a thick layer of sand forming a roadbed around the circumference. A 6 cm radius hard rubber wheel, with a support stationary in the lab frame, rolled on the sand layer. We varied the speed of the table and the details of the suspension of the wheel. The onset of the ripple pattern exhibits a sharp threshold and was strongly subcritical with a large hysteresis as a function of the speed of the table. The ripple pattern appears as small patches of travelling waves which eventually spread to the entire circumference. The ripples move slowly in the driving direction. Interesting secondary dynamics of the saturated ripples were observed. All of these effects are captured qualitatively by a 2D soft particle simulations. The simulations clearly indicate that neither compaction nor particle size segregation are crucial for the appearance of the ripples, and we present a simple model to describe the wavelength and amplitude of the ripples.

  17. Process for making boron nitride using sodium cyanide and boron

    DOEpatents

    Bamberger, Carlos E.

    1990-02-06

    This a very simple process for making boron nitride by mixing sodium cyanide and boron phosphate and heating the mixture in an inert atmosphere until a reaction takes place. The product is a white powder of boron nitride that can be used in applications that require compounds that are stable at high temperatures and that exhibit high electrical resistance.

  18. Process for making boron nitride using sodium cyanide and boron

    DOEpatents

    Bamberger, Carlos E.

    1990-01-01

    This a very simple process for making boron nitride by mixing sodium cyanide and boron phosphate and heating the mixture in an inert atmosphere until a reaction takes place. The product is a white powder of boron nitride that can be used in applications that require compounds that are stable at high temperatures and that exhibit high electrical resistance.

  19. Boronated liposome development and evaluation

    SciTech Connect

    Hawthorne, M.F.

    1995-11-01

    The boronated liposome development and evaluation effort consists of two separate tasks. The first is the development of new boron compounds and the synthesis of known boron species with BNCT potential. These compounds are then encapsulated within liposomes for the second task, biodistribution testing in tumor-bearing mice, which examines the potential for the liposomes and their contents to concentrate boron in cancerous tissues.

  20. Mineral of the month: boron

    USGS Publications Warehouse

    Lyday, Phyllis A.

    2005-01-01

    What does boron have to do with baseball, apple pie, motherhood and Chevrolet? Boron minerals and chemicals are used in the tanning of leather baseballs and gloves; in micro-fertilizer to grow apples and in the glass and enamels of bakewares to cook apple pie; in boron detergents for soaking baby clothes and diapers; and in fiberglass parts for the Chevrolet Corvette.

  1. Status of Boron Combustion Research

    DTIC Science & Technology

    1984-10-01

    layer . . . . . . . . . . . . . . . . . . . . . . . . . . 10 5 Vaporization of boron oxide drops In wet and dry .-. environments. From Turns et al . ([1...19 10 SEN photographs of boron slurry agglomerates: a. Oxide layer present: b. Oxide layer absent.From Turns et al . [7...21 -- f- 11 Ignition of boron agglomerates as a function of particle and agglomerate diameters. From Shevahuk et al . [26

  2. Method for separating boron isotopes

    DOEpatents

    Rockwood, Stephen D.

    1978-01-01

    A method of separating boron isotopes .sup.10 B and .sup.11 B by laser-induced selective excitation and photodissociation of BCl.sub.3 molecules containing a particular boron isotope. The photodissociation products react with an appropriate chemical scavenger and the reaction products may readily be separated from undissociated BCl.sub.3, thus effecting the desired separation of the boron isotopes.

  3. In Vivo Boron Uptake Determination for Boron Neutron Capture Synovectomy

    SciTech Connect

    Binello, Emanuela; Shortkroff, Sonya; Yanch, Jacquelyn C.

    1999-06-06

    Boron neutron capture synovectomy (BNCS) has been proposed as a new application of the boron neutron capture reaction for the treatment of rheumatoid arthritis. In BNCS, a boron compound is injected into the joint space, where it is taken up by the synovium. The joint is then irradiated with neutrons of a desired energy range, inducing the boron neutron capture reaction in boron-loaded cells. Boron uptake by the synovium is an important parameter in the assessment of the potential of BNCS and in the determination of whether to proceed to animal irradiations for the testing of therapeutic efficacy. We present results from an investigation of boron uptake in vivo by the synovium.

  4. Minerals Yearbook 1989: Boron

    SciTech Connect

    Lyday, P.A.

    1990-08-01

    U.S. production and sales of boron minerals and chemicals decreased during the year. Domestically, glass fiber insulation was the largest use for borates, followed by sales to distributors, textile-grade glass fibers, and borosilicate glasses. California was the only domestic source of boron minerals. The United States continued to provide essentially all of its own supply while maintaining a strong position as a source of sodium borate products and boric acid exported to foreign markets. Supplementary U.S. imports of Turkish calcium borate and calcium-sodium borate ores, borax, and boric acid, primarily for various glass uses, continued.

  5. Boron hydride polymer coated substrates

    DOEpatents

    Pearson, R.K.; Bystroff, R.I.; Miller, D.E.

    1986-08-27

    A method is disclosed for coating a substrate with a uniformly smooth layer of a boron hydride polymer. The method comprises providing a reaction chamber which contains the substrate and the boron hydride plasma. A boron hydride feed stock is introduced into the chamber simultaneously with the generation of a plasma discharge within the chamber. A boron hydride plasma of ions, electrons and free radicals which is generated by the plasma discharge interacts to form a uniformly smooth boron hydride polymer which is deposited on the substrate.

  6. Boron hydride polymer coated substrates

    DOEpatents

    Pearson, Richard K.; Bystroff, Roman I.; Miller, Dale E.

    1987-01-01

    A method is disclosed for coating a substrate with a uniformly smooth layer of a boron hydride polymer. The method comprises providing a reaction chamber which contains the substrate and the boron hydride plasma. A boron hydride feed stock is introduced into the chamber simultaneously with the generation of a plasma discharge within the chamber. A boron hydride plasma of ions, electrons and free radicals which is generated by the plasma discharge interacts to form a uniformly smooth boron hydride polymer which is deposited on the substrate.

  7. Fabrication of boron sputter targets

    SciTech Connect

    Makowiecki, Daniel M.; McKernan, Mark A.

    1995-01-01

    A process for fabricating high density boron sputtering targets with sufficient mechanical strength to function reliably at typical magnetron sputtering power densities and at normal process parameters. The process involves the fabrication of a high density boron monolithe by hot isostatically compacting high purity (99.9%) boron powder, machining the boron monolithe into the final dimensions, and brazing the finished boron piece to a matching boron carbide (B.sub.4 C) piece, by placing aluminum foil there between and applying pressure and heat in a vacuum. An alternative is the application of aluminum metallization to the back of the boron monolithe by vacuum deposition. Also, a titanium based vacuum braze alloy can be used in place of the aluminum foil.

  8. Fabrication of boron sputter targets

    DOEpatents

    Makowiecki, D.M.; McKernan, M.A.

    1995-02-28

    A process is disclosed for fabricating high density boron sputtering targets with sufficient mechanical strength to function reliably at typical magnetron sputtering power densities and at normal process parameters. The process involves the fabrication of a high density boron monolithe by hot isostatically compacting high purity (99.9%) boron powder, machining the boron monolithe into the final dimensions, and brazing the finished boron piece to a matching boron carbide (B{sub 4}C) piece, by placing aluminum foil there between and applying pressure and heat in a vacuum. An alternative is the application of aluminum metallization to the back of the boron monolithe by vacuum deposition. Also, a titanium based vacuum braze alloy can be used in place of the aluminum foil. 7 figs.

  9. Determination of phase stability of elemental boron.

    PubMed

    White, Mary Anne; Cerqueira, Anthony B; Whitman, Catherine A; Johnson, Michel B; Ogitsu, Tadashi

    2015-03-16

    Boron is an important element, used in applications from superhard materials to superconductors. Boron exists in several forms (allotropes) and, surprisingly, it was not known which form (α or β) is stable at ambient conditions. Through experiment, we quantify the relative stability of α-boron and β-boron as a function of temperature. The ground-state energies of α-boron and β-boron are nearly identical. For all temperatures up to 2000 K, the complicated β-boron structure is more stable than the simpler α-boron structure at ambient pressure. Below 1000 K, β-boron is entropically stabilized with respect to α-boron owing to its partially occupied sites, whereas at higher temperatures β-boron is enthalpically stabilized with respect to α-boron. We show that α-boron only becomes stable on application of pressure.

  10. Process for microwave sintering boron carbide

    DOEpatents

    Holcombe, C.E.; Morrow, M.S.

    1993-10-12

    A method of microwave sintering boron carbide comprises leaching boron carbide powder with an aqueous solution of nitric acid to form a leached boron carbide powder. The leached boron carbide powder is coated with a glassy carbon precursor to form a coated boron carbide powder. The coated boron carbide powder is consolidated in an enclosure of boron nitride particles coated with a layer of glassy carbon within a container for microwave heating to form an enclosed coated boron carbide powder. The enclosed coated boron carbide powder is sintered within the container for microwave heating with microwave energy.

  11. Process for microwave sintering boron carbide

    DOEpatents

    Holcombe, Cressie E.; Morrow, Marvin S.

    1993-01-01

    A method of microwave sintering boron carbide comprises leaching boron carbide powder with an aqueous solution of nitric acid to form a leached boron carbide powder. The leached boron carbide powder is coated with a glassy carbon precursor to form a coated boron carbide powder. The coated boron carbide powder is consolidated in an enclosure of boron nitride particles coated with a layer of glassy carbon within a container for microwave heating to form an enclosed coated boron carbide powder. The enclosed coated boron carbide powder is sintered within the container for microwave heating with microwave energy.

  12. Boron and Compounds

    Integrated Risk Information System (IRIS)

    EPA 635 / 04 / 052 www.epa.gov / iris TOXICOLOGICAL REVIEW OF BORON AND COMPOUNDS ( CAS No . 7440 - 42 - 8 ) In Support of Summary Information on the Integrated Risk Information System ( IRIS ) June 2004 U.S . Environmental Protection Agency Washington , DC DISCLAIMER This document has been reviewed

  13. Methods of producing continuous boron carbide fibers

    SciTech Connect

    Garnier, John E.; Griffith, George W.

    2015-12-01

    Methods of producing continuous boron carbide fibers. The method comprises reacting a continuous carbon fiber material and a boron oxide gas within a temperature range of from approximately 1400.degree. C. to approximately 2200.degree. C. Continuous boron carbide fibers, continuous fibers comprising boron carbide, and articles including at least a boron carbide coating are also disclosed.

  14. Nothing Boring About Boron.

    PubMed

    Pizzorno, Lara

    2015-08-01

    The trace mineral boron is a micronutrient with diverse and vitally important roles in metabolism that render it necessary for plant, animal, and human health, and as recent research suggests, possibly for the evolution of life on Earth. As the current article shows, boron has been proven to be an important trace mineral because it (1) is essential for the growth and maintenance of bone; (2) greatly improves wound healing; (3) beneficially impacts the body's use of estrogen, testosterone, and vitamin D; (4) boosts magnesium absorption; (5) reduces levels of inflammatory biomarkers, such as high-sensitivity C-reactive protein (hs-CRP) and tumor necrosis factor α (TNF-α); (6) raises levels of antioxidant enzymes, such as superoxide dismutase (SOD), catalase, and glutathione peroxidase; (7) protects against pesticide-induced oxidative stress and heavy-metal toxicity; (8) improves the brains electrical activity, cognitive performance, and short-term memory for elders; (9) influences the formation and activity of key biomolecules, such as S-adenosyl methionine (SAM-e) and nicotinamide adenine dinucleotide (NAD(+)); (10) has demonstrated preventive and therapeutic effects in a number of cancers, such as prostate, cervical, and lung cancers, and multiple and non-Hodgkin's lymphoma; and (11) may help ameliorate the adverse effects of traditional chemotherapeutic agents. In none of the numerous studies conducted to date, however, do boron's beneficial effects appear at intakes > 3 mg/d. No estimated average requirements (EARs) or dietary reference intakes (DRIs) have been set for boron-only an upper intake level (UL) of 20 mg/d for individuals aged ≥ 18 y. The absence of studies showing harm in conjunction with the substantial number of articles showing benefits support the consideration of boron supplementation of 3 mg/d for any individual who is consuming a diet lacking in fruits and vegetables or who is at risk for or has osteopenia; osteoporosis; osteoarthritis (OA

  15. Geologic Map of the Wenatchee 1:100,000 Quadrangle, Central Washington: A Digital Database

    USGS Publications Warehouse

    Tabor, R.W.; Waitt, R.B.; Frizzell, V.A.; Swanson, D.A.; Byerly, G.R.; Bentley, R.D.

    2005-01-01

    This digital map database has been prepared by R.W. Tabor from the published Geologic map of the Wenatchee 1:100,000 Quadrangle, Central Washington. Together with the accompanying text files as PDF, it provides information on the geologic structure and stratigraphy of the area covered. The database delineates map units that are identified by general age and lithology following the stratigraphic nomenclature of the U.S. Geological Survey. The authors mapped most of the bedrock geology at 1:100,000 scale, but compiled Quaternary units at 1:24,000 scale. The Quaternary contacts and structural data have been much simplified for the 1:100,000-scale map and database. The spatial resolution (scale) of the database is 1:100,000 or smaller. This database depicts the distribution of geologic materials and structures at a regional (1:100,000) scale. The report is intended to provide geologic information for the regional study of materials properties, earthquake shaking, landslide potential, mineral hazards, seismic velocity, and earthquake faults. In addition, the report contains information and interpretations about the regional geologic history and framework. However, the regional scale of this report does not provide sufficient detail for site development purposes.

  16. Impact of boron dilution accidents on low boron PWR safety

    SciTech Connect

    Papukchiev, A.; Liu, Y.; Schaefer, A.

    2006-07-01

    In conventional pressurized water reactor (PWR) designs, soluble boron is used for reactivity control over core fuel cycle. As an inadvertent reduction of the boron concentration during a boron dilution accident could introduce positive reactivity and have a negative impact on PWR safety, design changes to reduce boron concentration in the reactor coolant are of general interest. In the framework of an investigation into the feasibility of low boron design, a PWR core configuration based on fuel with higher gadolinium (Gd) load has been developed which permits to reduce the natural boron concentration at begin of cycle (BOC) to 518 ppm. For the assessment of the potential safety advantages, a boron dilution accident due to small break loss-of-coolant-accident (SBLOCA) has been simulated with the system code ATHLET for two PWR core designs: a low boron design and a standard core design. The results from the comparative analyses showed that the impact of the boron dilution accident on the new PWR design safety is significantly lower in comparison with the standard design. The new reactor design provided at least 4, 4% higher reactivity margin to recriticality during the whole accident which is equivalent to the negative reactivity worth of additional 63% of all control rods fully inserted in to the core. (authors)

  17. Structures, stability, mechanical and electronic properties of α-boron and α∗-boron

    NASA Astrophysics Data System (ADS)

    He, Chaoyu; Zhong, J. X.

    2013-04-01

    The structures, stability, mechanical and electronic properties of α-boron and a promising metastable boron phase (α*-boron) have been studied by first-principles calculations. α-boron and α*-boron consist of equivalent icosahedra B12 clusters in different connecting configurations of "3S-6D-3S" and "2S-6D-4S", respectively. The total energy calculations show that α*-boron is less stable than α-boron but more favorable than the well-known β-boron and γ-boron at zero pressure. Both α-boron and α*-boron are confirmed dynamically and mechanically stable. The mechanical and electronic properties of α-boron and α*-boron indicate that they are potential superhard semiconducting phases of element boron.

  18. Detail, unit 5, pump motor. This motor is also 1,100 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail, unit 5, pump motor. This motor is also 1,100 hp and is manufactured by the Electric Products Company. Note additional gauges and box attached to side. Unit 6 is identical to this unit - Wellton-Mohawk Irrigation System, Pumping Plant No. 1, Bounded by Gila River & Union Pacific Railroad, Wellton, Yuma County, AZ

  19. Detail, unit 3, 1,100 horsepower (hp) pump motor. Manufactured by ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail, unit 3, 1,100 horsepower (hp) pump motor. Manufactured by the Electric Products Company, Cleveland, Ohio, USA. Units 1,2, and 4 are identical to this unit - Wellton-Mohawk Irrigation System, Pumping Plant No. 1, Bounded by Gila River & Union Pacific Railroad, Wellton, Yuma County, AZ

  20. Geologic map of the Priest Rapids 1:100,000 quadrangle, Washington

    SciTech Connect

    Reidel, S.P.; Fecht, K.R.

    1993-09-01

    This map of the Priest Rapids 1:100,000-scale quadrangle, Washington, shows the geology of one of fifteen complete or partial 1:100,000-scale quadrangles that cover the southeast quadrant of Washington. Geologic maps of these quadrangles have been compiled by geologists with the Washington Division of Geology and Earth Resources (DGER) and Washington State University and are the principal data sources for a 1:250,000scale geologic map of the southeast quadrant of Washington, which is in preparation. Eleven of those quadrangles are being released as DGER open-file reports (listed below). The map of the Wenatchee quadrangle has been published by the US Geological Survey (Tabor and others, 1982), and the Moses Lake (Gulick, 1990a), Ritzville (Gulick, 1990b), and Rosalia (Waggoner, 1990) quadrangles have already been released. The geology of the Priest Rapids quadrangle has not previously been compiled at 1:100,000 scale. Furthermore, this is the first 1:100,000 or smaller scale geologic map of the area to incorporate both bedrock and surficial geology. This map was compiled in 1992, using published and unpublished geologic maps as sources of data.

  1. Boron nitride nanotubes.

    PubMed

    Chopra, N G; Luyken, R J; Cherrey, K; Crespi, V H; Cohen, M L; Louie, S G; Zettl, A

    1995-08-18

    The successful synthesis of pure boron nitride (BN) nanotubes is reported here. Multi-walled tubes with inner diameters on the order of 1 to 3 nanometers and with lengths up to 200 nanometers were produced in a carbon-free plasma discharge between a BN-packed tungsten rod and a cooled copper electrode. Electron energy-loss spectroscopy on individual tubes yielded B:N ratios of approximately 1, which is consistent with theoretical predictions of stable BN tube structures.

  2. Method of fabricating boron containing coatings

    DOEpatents

    Makowiecki, D.M.; Jankowski, A.F.

    1999-04-27

    Hard coatings are fabricated from boron nitride, cubic boron nitride, and multilayer boron/cubic boron nitride, and the fabrication thereof involves magnetron sputtering in a selected atmosphere. These hard coatings may be applied to tools and engine and other parts, as well to reduce wear on tribological surfaces and electronic devices. These boron coatings contain no morphological growth features. For example, the boron is formed in an inert (e.g. argon) atmosphere, while the cubic boron nitride is formed in a reactive (e.g. nitrogen) atmosphere. The multilayer boron/cubic boron nitride, is produced by depositing alternate layers of boron and cubic boron nitride, with the alternate layers having a thickness of 1 nanometer to 1 micrometer, and at least the interfaces of the layers may be discrete or of a blended or graded composition. 3 figs.

  3. Method of fabricating boron containing coatings

    DOEpatents

    Makowiecki, Daniel M.; Jankowski, Alan F.

    1999-01-01

    Hard coatings are fabricated from boron nitride, cubic boron nitride, and multilayer boron/cubic boron nitride, and the fabrication thereof involves magnetron sputtering in a selected atmosphere. These hard coatings may be applied to tools and engine and other parts, as well to reduce wear on tribological surfaces and electronic devices. These boron coatings contain no morphological growth features. For example, the boron is formed in an inert (e.g. argon) atmosphere, while the cubic boron nitride is formed in a reactive (e.g. nitrogen) atmosphere. The multilayer boron/cubic boron nitride, is produced by depositing alternate layers of boron and cubic boron nitride, with the alternate layers having a thickness of 1 nanometer to 1 micrometer, and at least the interfaces of the layers may be discrete or of a blended or graded composition.

  4. View looks east northeast (64°) along North Base Road, showing ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View looks east northeast (64°) along North Base Road, showing North Base as it appears on approach by automobile. From left to right, one sees Building 4505 with its ancillary buildings; Building 4500, Control Tower; followed by Buildings 4402 (Hangar No. 2), 4401 (Hangar No. 1), and 4305 (Unicon Portable Hangar) with their respective ancillary structures. - Edwards Air Force Base, North Base, North Base Road, Boron, Kern County, CA

  5. Boron isotopic compositions of some boron minerals

    SciTech Connect

    Oi, Takao; Musashi, Masaaki; Ossaka, Tomoko; Kakihana, Hidetake ); Nomura, Masao; Okamoto, Makoto )

    1989-12-01

    Boron minerals that have different structural formulae but are supposed to have the same geologic origin have been collected and analyzed for the {sup 11}B/{sup 10}B isotopic ratio. It has been reconfirmed that minerals of marine origin have higher {sup 11}B/{sup 10}B ratios than those of nonmarine origin. It has been found that the sequence of decreasing {sup 11}B/{sup 10}B values among the minerals with the same geologic origin is; borax, tincal, kernite (Na borates) > ulexite (Na/Ca borate) > colemanite, iyoite, meyerhofferite (Ca borates). This sequence is explainable on the basis of the difference in crystal structure among the minerals. That is, minerals with high BO{sub 3}/BO{sub 4} ratios, (the ratio of the number of the BO{sub 3} triangle units to the number of the BO{sub 4} tetrahedron units in the structural formula of a mineral) have higher {sup 11}B/{sup 10}B ratios.

  6. Boron Clusters Come of Age

    ERIC Educational Resources Information Center

    Grimes, Russell N.

    2004-01-01

    Boron is the only element other than carbon that can build molecules of unlimited size by covalently boding to itself, a property known as catenation. In contrast to the chains and rings favored by carbon, boron arguably adopts a cluster motif that is reflected in the various forms of the pure element and in the huge area of polyhedral borane…

  7. Geologic map of the Richland 1:100,000 quadrangle, Washington

    SciTech Connect

    Reidel, S.P.; Fecht, K.R.

    1993-09-01

    This map of the Richland 1:100,000-scale quadrangle, Washington, shows the geology of one of fifteen complete or partial 1:100,000-scale quadrangles that cover the southeast quadrant of Washington. Geologic maps of these quadrangles have been compiled by geologists with the Washington Division of Geology and Earth Resources (DGER) and Washington State University and are the principal data sources for a 1:250,000-scale geologic map of the southeast quadrant of Washington, which is in preparation. Eleven of these quadrangles are being released as DGER open-file reports. The map of the Wenatchee quadrangle has been published by the US Geological Survey, and the Moses Lake, Ritzville quadrangles have already been released.

  8. Boron containing multilayer coatings and method of fabrication

    DOEpatents

    Makowiecki, Daniel M.; Jankowski, Alan F.

    1997-01-01

    Hard coatings are fabricated from multilayer boron/boron carbide, boron carbide/cubic boron nitride, and boron/boron nitride/boron carbide, and the fabrication thereof involves magnetron sputtering in a selected atmosphere. These hard coatings may be applied to tools and engine and other parts, as well to reduce wear on tribological surfaces and electronic devices. These boron coatings contain no morphological growth features. For example, the boron and boron carbide used in forming the multilayers are formed in an inert (e.g. argon) atmosphere, while the cubic boron nitride is formed in a reactive (e.g. nitrogen) atmosphere. The multilayer boron/boron carbide, and boron carbide/cubic boron nitride is produced by depositing alternate layers of boron, cubic boron nitride or boron carbide, with the alternate layers having a thickness of 1 nanometer to 1 micrometer, and at least the interfaces of the layers may be of a discrete or a blended or graded composition.

  9. 2. Big Creek Road, worm fence and road at trailhead. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. Big Creek Road, worm fence and road at trailhead. - Great Smoky Mountains National Park Roads & Bridges, Big Creek Road, Between State Route 284 & Big Creek Campground, Gatlinburg, Sevier County, TN

  10. 5. Big Creek Road, old bridge on Walnut Bottom Road, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. Big Creek Road, old bridge on Walnut Bottom Road, deck view. - Great Smoky Mountains National Park Roads & Bridges, Big Creek Road, Between State Route 284 & Big Creek Campground, Gatlinburg, Sevier County, TN

  11. 4. Big Creek Road, old bridge on Walnut Bottom Road, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. Big Creek Road, old bridge on Walnut Bottom Road, elevation view. - Great Smoky Mountains National Park Roads & Bridges, Big Creek Road, Between State Route 284 & Big Creek Campground, Gatlinburg, Sevier County, TN

  12. Functionalized boron nitride nanotubes

    DOEpatents

    Sainsbury, Toby; Ikuno, Takashi; Zettl, Alexander K

    2014-04-22

    A plasma treatment has been used to modify the surface of BNNTs. In one example, the surface of the BNNT has been modified using ammonia plasma to include amine functional groups. Amine functionalization allows BNNTs to be soluble in chloroform, which had not been possible previously. Further functionalization of amine-functionalized BNNTs with thiol-terminated organic molecules has also been demonstrated. Gold nanoparticles have been self-assembled at the surface of both amine- and thiol-functionalized boron nitride Nanotubes (BNNTs) in solution. This approach constitutes a basis for the preparation of highly functionalized BNNTs and for their utilization as nanoscale templates for assembly and integration with other nanoscale materials.

  13. METHOD OF COATING SURFACES WITH BORON

    DOEpatents

    Martin, G.R.

    1949-10-11

    A method of forming a thin coating of boron on metallic, glass, or other surfaces is described. The method comprises heating the article to be coated to a temperature of about 550 d C in an evacuated chamber and passing trimethyl boron, triethyl boron, or tripropyl boron in the vapor phase and under reduced pressure into contact with the heated surface causing boron to be deposited in a thin film.

  14. Boron implanted strontium titanate

    NASA Astrophysics Data System (ADS)

    Cooper, C. J. M.

    Single crystals of strontium titanate implanted with boron were found to have highly conductive surface layers. The effects of varying dose from 10 to the 16th power to 10 to the 17th power ions/sq cm, implantation voltage from 50 to 175 keV and annealing conditions on the room temperature surface resistance and Hall mobility are presented. Variation of the implantation voltage did not have a major effect on the sheet resistances obtained by boron implantation of strontium titanate, while dose and annealing conditions have major effects. Doses of 5 x 10 to the 16th power ions/sq cm required annealing on the order of one hour at 500 K for maximum reduction of the room temperature resistance in the implanted layer. Samples implanted with a dose of 1 x 10 to the 17th power ions/sq cm required slightly higher temperatures (approximately 575 K) to obtain a minimum resistance at room temperature. Long term (several weeks) room temperature annealing was found to occur in high dose samples. After one to two months at room temperature followed by an anneal to 575 K, the surface resistances were found to be lower than those produced by the annealing of a freshly implanted sample to 575 K.

  15. 18. DETAIL OF HEAD GATE ABOUT 1,100 FEET NORTH OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    18. DETAIL OF HEAD GATE ABOUT 1,100 FEET NORTH OF 7TH AVENUE (SECTION 35), SHOWING CHANNEL IN WIHCH GATE WAS RAISED AND LOWERED. - Highline Canal, Sand Creek Lateral, Beginning at intersection of Peoria Street & Highline Canal in Arapahoe County (City of Aurora), Sand Creek lateral Extends 15 miles Northerly through Araphoe County, City & County of Denver, & Adams County to its end point, approximately 1/4 mile Southest of intersectioin of D Street & Ninth Avenue in Adams County (Rocky Mountain Arsenal, Commerce City Vicinity), Commerce City, Adams County, CO

  16. A new and effective approach to boron removal by using novel boron-specific fungi isolated from boron mining wastewater.

    PubMed

    Taştan, Burcu Ertit; Çakir, Dilara Nur; Dönmez, Gönül

    2016-01-01

    Boron-resistant fungi were isolated from the wastewater of a boron mine in Turkey. Boron removal efficiencies of Penicillium crustosum and Rhodotorula mucilaginosa were detected in different media compositions. Minimal Salt Medium (MSM) and two different waste media containing molasses (WM-1) or whey + molasses (WM-2) were tested to make this process cost effective when scaled up. Both isolates achieved high boron removal yields at the highest boron concentrations tested in MSM and WM-1. The maximum boron removal yield by P. crustosum was 45.68% at 33.95 mg l(-1) initial boron concentration in MSM, and was 38.97% at 42.76 mg l(-1) boron for R. mucilaginosa, which seemed to offer an economically feasible method of removing boron from the effluents.

  17. Quaternary Geology and Liquefaction Susceptibility, San Francisco, California 1:100,000 Quadrangle: A Digital Database

    USGS Publications Warehouse

    Knudsen, Keith L.; Noller, Jay S.; Sowers, Janet M.; Lettis, William R.

    1997-01-01

    This Open-File report is a digital geologic map database. This pamphlet serves to introduce and describe the digital data. There are no paper maps included in the Open-File report. The report does include, however, PostScript plot files containing the images of the geologic map sheets with explanations, as well as the accompanying text describing the geology of the area. For those interested in a paper plot of information contained in the database or in obtaining the PostScript plot files, please see the section entitled 'For Those Who Aren't Familiar With Digital Geologic Map Databases' below. This digital map database, compiled from previously unpublished data, and new mapping by the authors, represents the general distribution of surficial deposits in the San Francisco bay region. Together with the accompanying text file (sf_geo.txt or sf_geo.pdf), it provides current information on Quaternary geology and liquefaction susceptibility of the San Francisco, California, 1:100,000 quadrangle. The database delineates map units that are identified by general age and lithology following the stratigraphic nomenclature of the U.S. Geological Survey. The scale of the source maps limits the spatial resolution (scale) of the database to 1:100,000 or smaller. The content and character of the database, as well as three methods of obtaining the database, are described below.

  18. Nothing Boring About Boron

    PubMed Central

    Pizzorno, Lara

    2015-01-01

    The trace mineral boron is a micronutrient with diverse and vitally important roles in metabolism that render it necessary for plant, animal, and human health, and as recent research suggests, possibly for the evolution of life on Earth. As the current article shows, boron has been proven to be an important trace mineral because it (1) is essential for the growth and maintenance of bone; (2) greatly improves wound healing; (3) beneficially impacts the body’s use of estrogen, testosterone, and vitamin D; (4) boosts magnesium absorption; (5) reduces levels of inflammatory biomarkers, such as high-sensitivity C-reactive protein (hs-CRP) and tumor necrosis factor α (TNF-α); (6) raises levels of antioxidant enzymes, such as superoxide dismutase (SOD), catalase, and glutathione peroxidase; (7) protects against pesticide-induced oxidative stress and heavy-metal toxicity; (8) improves the brains electrical activity, cognitive performance, and short-term memory for elders; (9) influences the formation and activity of key biomolecules, such as S-adenosyl methionine (SAM-e) and nicotinamide adenine dinucleotide (NAD+); (10) has demonstrated preventive and therapeutic effects in a number of cancers, such as prostate, cervical, and lung cancers, and multiple and non-Hodgkin’s lymphoma; and (11) may help ameliorate the adverse effects of traditional chemotherapeutic agents. In none of the numerous studies conducted to date, however, do boron’s beneficial effects appear at intakes > 3 mg/d. No estimated average requirements (EARs) or dietary reference intakes (DRIs) have been set for boron—only an upper intake level (UL) of 20 mg/d for individuals aged ≥ 18 y. The absence of studies showing harm in conjunction with the substantial number of articles showing benefits support the consideration of boron supplementation of 3 mg/d for any individual who is consuming a diet lacking in fruits and vegetables or who is at risk for or has osteopenia; osteoporosis

  19. Copper passivation of boron in silicon and boron reactivation kinetics

    NASA Astrophysics Data System (ADS)

    Aboelfotoh, M. O.; Svensson, B. G.

    1991-12-01

    Copper passivation of substitutional boron in single-crystal silicon and the reactivation kinetics of the passivated boron have been investigated with the use of Schottky-barrier structures formed by the deposition of copper on boron-doped silicon at room temperature. It is found that passivation of the boron acceptors occurs after copper deposition. The results suggest that the fast-diffusing interstitial Cu+ passivates the boron acceptors by forming neutral B-Cu complexes, rather than by direct compensation. No compensating donor levels associated with Cu are observed. These results are consistent with recent theoretical predictions. The reactivation kinetics are first order with an activation energy of 0.89 eV, and the annealing process is found to be controlled by long-range diffusion, rather than by pure dissociation. The thermal dissociation of the B-Cu complexes is driven by the formation of the copper silicide η'-Cu3Si, indicating the importance of silicide formation in the reactivation of the boron acceptors.

  20. Reducing Boron Toxicity by Microbial Sequestration

    SciTech Connect

    Hazen, T.; Phelps, T.J.

    2002-01-01

    While electricity is a clean source of energy, methods of electricity-production, such as the use of coal-fired power plants, often result in significant environmental damage. Coal-fired electrical power plants produce air pollution, while contaminating ground water and soils by build-up of boron, which enters surrounding areas through leachate. Increasingly high levels of boron in soils eventually overcome boron tolerance levels in plants and trees, resulting in toxicity. Formation of insoluble boron precipitates, mediated by mineral-precipitating bacteria, may sequester boron into more stable forms that are less available and toxic to vegetation. Results have provided evidence of microbially-facilitated sequestration of boron into insoluble mineral precipitates. Analyses of water samples taken from ponds with high boron concentrations showed that algae present contained 3-5 times more boron than contained in the water in the samples. Boron sequestration may also be facilitated by the incorporation of boron within algal cells. Experiments examining boron sequestration by algae are in progress. In bacterial experiments with added ferric citrate, the reduction of iron by the bacteria resulted in an ironcarbonate precipitate containing boron. An apparent color change showing the reduction of amorphous iron, as well as the precipitation of boron with iron, was more favorable at higher pH. Analysis of precipitates by X-ray diffraction, scanning electron microscopy, and inductively coupled plasma mass spectroscopy revealed mineralogical composition and biologicallymediated accumulation of boron precipitates in test-tube experiments.

  1. Nano boron nitride flatland.

    PubMed

    Pakdel, Amir; Bando, Yoshio; Golberg, Dmitri

    2014-02-07

    Recent years have witnessed many breakthroughs in research on two-dimensional (2D) nanomaterials, among which is hexagonal boron nitride (h-BN), a layered material with a regular network of BN hexagons. This review provides an insight into the marvellous nano BN flatland, beginning with a concise introduction to BN and its low-dimensional nanostructures, followed by an overview of the past and current state of research on 2D BN nanostructures. A comprehensive review of the structural characteristics and synthetic routes of BN monolayers, multilayers, nanomeshes, nanowaves, nanoflakes, nanosheets and nanoribbons is presented. In addition, electronic, optical, thermal, mechanical, magnetic, piezoelectric, catalytic, ecological, biological and wetting properties, applications and research perspectives for these novel 2D nanomaterials are discussed.

  2. Neutron detectors comprising boron powder

    DOEpatents

    Wang, Zhehui; Morris, Christopher; Bacon, Jeffrey Darnell; Makela, Mark F; Spaulding, Randy Jay

    2013-05-21

    High-efficiency neutron detector substrate assemblies comprising a first conductive substrate, wherein a first side of the substrate is in direct contact with a first layer of a powder material comprising .sup.10boron, .sup.10boron carbide or combinations thereof, and wherein a conductive material is in proximity to the first layer of powder material; and processes of making said neutron detector substrate assemblies.

  3. Boron diffusion in silicon devices

    DOEpatents

    Rohatgi, Ajeet; Kim, Dong Seop; Nakayashiki, Kenta; Rounsaville, Brian

    2010-09-07

    Disclosed are various embodiments that include a process, an arrangement, and an apparatus for boron diffusion in a wafer. In one representative embodiment, a process is provided in which a boric oxide solution is applied to a surface of the wafer. Thereafter, the wafer is subjected to a fast heat ramp-up associated with a first heating cycle that results in a release of an amount of boron for diffusion into the wafer.

  4. Characterization of electrodeposited elemental boron

    SciTech Connect

    Jain, Ashish; Anthonysamy, S. Ananthasivan, K.; Ranganathan, R.; Mittal, Vinit; Narasimhan, S.V.; Vasudeva Rao, P.R.

    2008-07-15

    Elemental boron was produced through electrowinning from potassium fluoroborate dissolved in a mixture of molten potassium fluoride and potassium chloride. The characteristics of the electrodeposited boron (raw boron) as well as the water and acid-leached product (processed boron) were studied. The chemical purity, specific surface area, size distribution of particles and X-ray crystallite size of the boron powders were investigated. The morphology of the deposits was examined using scanning electron microscopy (SEM). The chemical state of the matrix, as well as the impurity phases present in them, was established using X-ray photoelectron spectroscopy (XPS). In order to interpret and understand the results obtained, a thermodynamic analysis was carried out. The gas-phase corrosion in the head space as well as the chemistry behind the leaching process were interpreted using this analysis. The ease of oxidation of these powders in air was investigated using differential thermal analysis (DTA) coupled with thermogravimetry (TG). From the results obtained in this study it was established that elemental boron powder with a purity of 95-99% could be produced using a high temperature molten salt electrowinning process. The major impurities were found to be oxygen, carbon, iron and nickel.

  5. Exposure rate constants and lead shielding values for over 1,100 radionuclides.

    PubMed

    Smith, David S; Stabin, Michael G

    2012-03-01

    The authors have assembled a compilation of exposure rate constants, ƒ-factors, and lead shielding thicknesses for more than 1,100 radionuclides described in ICRP Publication 107. Physical data were taken from well established reference sources for mass-energy absorption coefficients in air, attenuation coefficients, and buildup factors in lead and other variables.The data agreed favorably for the most part with those of other investigators; thus this compilation provides an up-to-date and sizeable database of these data, which are of interest to many for routine calculations. Emissions were also segregated by emitting nuclide, and decay product emissions were emitted from the calculated coefficients, thus for the first time providing for the calculation of exposure rates from arbitrary mixtures of nuclides in arbitrary equilibrium states.

  6. Processing of boron carbide

    NASA Astrophysics Data System (ADS)

    Cho, Namtae

    The processing of boron carbide powder including sintering optimization, green body optimization and sintering behavior of nano-sized boron carbide was investigated for the development of complex shaped body armor. Pressureless sintered B4C relative densities as high as 96.7% were obtained by optimizing the soak temperature, and holding at that temperature for the minimum time required to reach terminal density. Although the relative densities of pressureless sintered specimens were lower than that of commercially produced hot-pressed B4C, their (Vickers) hardness values were comparable. For 4.45 cm dia. 1.35 cm height disk-shaped specimens, pressureless sintered to at least 93.0% relative density, post-hot isostatic pressing resulted in vast increases in relative densities (e.g. 100.0%) and hardness values significantly greater than that of commercially produced hot-pressed B 4C. The densification behavior of 20-40nm graphite-coated B4C nano-particles was studied using dilatometry, x-ray diffraction and electron microscopy. The higher than expected sintering onset from a nano-scale powder (˜1500°C) was caused by remnant B2O3 not removed by methanol washing, keeping particles separated until volatilization, and the carbon coatings, which imposed particle to particle contact of a substance more refractory than B4C. Solid state sintering (1500-1850°C) was followed by an arrest in contraction attributed to formation of eutectic liquid droplets of size more than 10X the original nano-particles. These droplets, induced to form well below known B4C-graphite eutectic temperatures by the high surface energy of nanoparticles, are interpreted to have quickly solidified to form a vast number of voids in particle packing, which in turn, impeded continued solid state sintering. Starting at 2200°C, a permanent liquid phase formed which facilitated a rapid measured contraction by liquid phase sintering and/or compact slumping.

  7. 7. LASSEN PARK ROAD BRIDGE AT SULFUR WORKS. NOTE ROAD ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. LASSEN PARK ROAD BRIDGE AT SULFUR WORKS. NOTE ROAD TRAVERSING DISTANT RIDGE BEYOND BRIDGE. SEEN FROM WEST OF HIGHWAY FROM OLD HIGHWAY LOOP. LOOKING E. - Lassen Park Road, Mineral, Tehama County, CA

  8. Boronated porhyrins and methods for their use

    DOEpatents

    Miura, Michiko; Shelnutt, John A.; Slatkin, Daniel N.

    1999-03-02

    The present invention covers boronated porphyrins containing multiple carborane cages which selectively accumulate in neoplastic tissue within the irradiation volume and thus can be used in cancer therapies such as boron neutron capture therapy and photodynamic therapy.

  9. Boronated porhyrins and methods for their use

    DOEpatents

    Miura, M.; Shelnutt, J.A.; Slatkin, D.N.

    1999-03-02

    The present invention covers boronated porphyrins containing multiple carborane cages which selectively accumulate in neoplastic tissue within the irradiation volume and thus can be used in cancer therapies such as boron neutron capture therapy and photodynamic therapy. 3 figs.

  10. Synthesis and Utility of Dihydropyridine Boronic Esters**

    PubMed Central

    Panda, Santanu; Coffin, Aaron; Nguyen, Q. Nhu; Tantillo, Dean; Ready, Joseph M.

    2016-01-01

    When activated by an acylating agent, pyridine boronic esters react with organometallic reagents to form a dihydropyridine boronic ester. This intermediate allows access to a number of valuable substituted pyridine, dihydropyridine and piperidine products. PMID:26694785

  11. Synthesis and Utility of Dihydropyridine Boronic Esters.

    PubMed

    Panda, Santanu; Coffin, Aaron; Nguyen, Q Nhu; Tantillo, Dean J; Ready, Joseph M

    2016-02-05

    When activated by an acylating agent, pyridine boronic esters react with organometallic reagents to form a dihydropyridine boronic ester. This intermediate allows access to a number of valuable substituted pyridine, dihydropyridine, and piperidine products.

  12. Methods for boron delivery to mammalian tissue

    DOEpatents

    Hawthorne, M. Frederick; Feaks, Debra A.; Shelly, Kenneth J.

    2003-01-01

    Boron neutron capture therapy can be used to destroy tumors. This treatment modality is enhanced by delivering compounds to the tumor site where the compounds have high concentrations of boron, the boron compounds being encapsulated in the bilayer of a liposome or in the bilayer as well as the internal space of the liposomes. Preferred compounds, include carborane units with multiple boron atoms within the carborane cage structure. Liposomes with increased tumor specificity may also be used.

  13. Wettability of boron carbide

    SciTech Connect

    Torvund, T.; Akselsen, O.M.; Ulvensoeen, J.H.; Grong, O.

    1994-12-31

    The wettability of boron carbide has been examined by means of the sessile drop method, using the following candidate alloys: (96wt%AG-4wt%Ti), (Ag-26.5wt%Cu-3wt%Ti), (Sn-10wt%Ag-4wt%Ti), Sn(99.95wt%) and Al(99.99wt%). The results show that B{sub 4}C is completely wetted by the Ag-based alloys. Sn-10wt%Ag-4wt%Ti alloy and pure Al partly wet the B{sub 4}C surface, while pure Sn does not wet B{sub 4}C at all. For all the alloys used, except pure Sn, a reaction layer was observed at the interface between the ceramic part and the metal drop. Although the spreading kinetics of the Al-drop was much slower compared with the Ti-containing alloys, the reaction rate was considerably higher in the former case. This suggests that aluminium is an attractive candidate material for brazing of B{sub 4}C. Formation of the low melting B{sub 2}O{sub 3} at the B{sub 4}C surface may cause oxidation of the filler metal during joining, which, in turn, leads to a low bond strength.

  14. Mineral resource of the month: boron

    USGS Publications Warehouse

    Lyday, Phyllis A.

    2005-01-01

    What does boron have to do with baseball, apple pie, motherhood and Chevrolet? Boron minerals and chemicals are used in the tanning of leather baseballs and gloves; in micro-fertilizer to grow apples and in the glass and enamels of bakewares to cook apple pie; in boron detergents for soaking baby clothes and diapers; and in fiberglass parts for the Chevrolet Corvette.

  15. Vehicular road influence areas

    NASA Astrophysics Data System (ADS)

    Huertas, María E.; Huertas, José I.; Valencia, Alexander

    2017-02-01

    Vehicle operation over paved and unpaved roads is an emission source that significantly contributes to air pollution. Emissions are derived from vehicle exhaust pipes and re-suspension of particulate matter generated by wind erosion and tire to road surface interactions. Environmental authorities require a methodology to evaluate road impact areas, which enable managers to initiate counter-measures, particularly under circumstances where historic meteorological and/or air quality data is unavailable. The present study describes an analytical and experimental work developed to establish a simplified methodology to estimate the area influenced by vehicular roads. AERMOD was chosen to model pollutant dispersion generated by two roads of common attributes (straight road over flat terrain) under the effects of several arbitrary chosen weather conditions. The resulting pollutant concentration vs. Distance curves collapsed into a single curve when concentration and distance were expressed as dimensionless numbers and this curve can be described by a beta distribution function. This result implied that average concentration at a given distance was proportional to emission intensity and that it showed minor sensitivity to meteorological conditions. Therefore, road influence was defined by the area adjacent to the road limited by distance at which the beta distribution function equaled the limiting value specified by the national air quality standard for the pollutant under consideration.

  16. Roads to Safety.

    ERIC Educational Resources Information Center

    Hauer, Ezra

    1991-01-01

    Contends that the level of safety built into roads is largely unpremeditated and that roads and highways are not as safe as they might be. Discusses practices, standards, and deficiencies in highway and traffic safety related to geometric design and traffic engineering. Recommends increased transportation engineering professionalism and public…

  17. Inter-comparison of boron concentration measurements at INFN-University of Pavia (Italy) and CNEA (Argentina).

    PubMed

    Portu, Agustina; Postuma, Ian; Gadan, Mario Alberto; Saint Martin, Gisela; Olivera, María Silvina; Altieri, Saverio; Protti, Nicoletta; Bortolussi, Silva

    2015-11-01

    An inter-comparison of three boron determination techniques was carried out between laboratories from INFN-University of Pavia (Italy) and CNEA (Argentina): alpha spectrometry (alpha-spect), neutron capture radiography (NCR) and quantitative autoradiography (QTA). Samples of different nature were analysed: liquid standards, liver homogenates and tissue samples from different treatment protocols. The techniques showed a good agreement in a concentration range of interest in BNCT (1-100ppm), thus demonstrating their applicability as precise methods to quantify boron and determine its distribution in tissues.

  18. Reprint of Inter-comparison of boron concentration measurements at INFN-University of Pavia (Italy) and CNEA (Argentina).

    PubMed

    Portu, Agustina; Postuma, Ian; Gadan, Mario Alberto; Saint Martin, Gisela; Olivera, María Silvina; Altieri, Saverio; Protti, Nicoletta; Bortolussi, Silva

    2015-12-01

    An inter-comparison of three boron determination techniques was carried out between laboratories from INFN-University of Pavia (Italy) and CNEA (Argentina): alpha spectrometry (alpha-spect), neutron capture radiography (NCR) and quantitative autoradiography (QTA). Samples of different nature were analysed: liquid standards, liver homogenates and tissue samples from different treatment protocols. The techniques showed a good agreement in a concentration range of interest in BNCT (1-100 ppm), thus demonstrating their applicability as precise methods to quantify boron and determine its distribution in tissues.

  19. Graphene on hexagonal boron nitride

    NASA Astrophysics Data System (ADS)

    Yankowitz, Matthew; Xue, Jiamin; LeRoy, B. J.

    2014-07-01

    The field of graphene research has developed rapidly since its first isolation by mechanical exfoliation in 2004. Due to the relativistic Dirac nature of its charge carriers, graphene is both a promising material for next-generation electronic devices and a convenient low-energy testbed for intrinsically high-energy physical phenomena. Both of these research branches require the facile fabrication of clean graphene devices so as not to obscure its intrinsic physical properties. Hexagonal boron nitride has emerged as a promising substrate for graphene devices as it is insulating, atomically flat and provides a clean charge environment for the graphene. Additionally, the interaction between graphene and boron nitride provides a path for the study of new physical phenomena not present in bare graphene devices. This review focuses on recent advancements in the study of graphene on hexagonal boron nitride devices from the perspective of scanning tunneling microscopy with highlights of some important results from electrical transport measurements.

  20. Boron doping a semiconductor particle

    DOEpatents

    Stevens, Gary Don; Reynolds, Jeffrey Scott; Brown, Louanne Kay

    1998-06-09

    A method (10,30) of boron doping a semiconductor particle using boric acid to obtain a p-type doped particle. Either silicon spheres or silicon powder is mixed with a diluted solution of boric acid having a predetermined concentration. The spheres are dried (16), with the boron film then being driven (18) into the sphere. A melt procedure mixes the driven boron uniformly throughout the sphere. In the case of silicon powder, the powder is metered out (38) into piles and melted/fused (40) with an optical furnace. Both processes obtain a p-type doped silicon sphere with desired resistivity. Boric acid is not a restricted chemical, is inexpensive, and does not pose any special shipping, handling, or disposal requirements.

  1. Boron doping a semiconductor particle

    DOEpatents

    Stevens, G.D.; Reynolds, J.S.; Brown, L.K.

    1998-06-09

    A method of boron doping a semiconductor particle using boric acid to obtain a p-type doped particle. Either silicon spheres or silicon powder is mixed with a diluted solution of boric acid having a predetermined concentration. The spheres are dried, with the boron film then being driven into the sphere. A melt procedure mixes the driven boron uniformly throughout the sphere. In the case of silicon powder, the powder is metered out into piles and melted/fused with an optical furnace. Both processes obtain a p-type doped silicon sphere with desired resistivity. Boric acid is not a restricted chemical, is inexpensive, and does not pose any special shipping, handling, or disposal requirements. 2 figs.

  2. Quaternary Geology and Liquefaction Susceptibility, Napa, California 1:100,000 Quadrangle: A Digital Database

    USGS Publications Warehouse

    Sowers, Janet M.; Noller, Jay S.; Lettis, William R.

    1998-01-01

    Earthquake-induced ground failures such as liquefaction have historically brought loss of life and damage to property and infrastructure. Observations of the effects of historical large-magnitude earthquakes show that the distribution of liquefaction phenomena is not random. Liquefaction is restricted to areas underlain by loose, cohesionless sands and silts that are saturated with water. These areas can be delineated on the basis of thorough geologic, geomorphic, and hydrologic mapping and map analysis (Tinsley and Holzer, 1990; Youd and Perkins, 1987). Once potential liquefaction zones are delineated, appropriate public and private agencies can prepare for and mitigate seismic hazard in these zones. In this study, we create a liquefaction susceptibility map of the Napa 1:100,000 quadrangle using Quaternary geologic mapping, analysis of historical liquefaction information, groundwater data, and data from other studies. The study is atterned after state-of-the-art studies by Youd (1973) Dupre and Tinsley (1980) and Dupre (1990) in the Monterey-Santa Cruz area, Tinsley and others (1985) in the Los Angeles area, and Youd and Perkins (1987) in San Mateo County, California. The study area comprises the northern San Francisco Metropolitan Area, including the cities of Santa Rosa, Vallejo, Napa, Novato, Martinez, and Fairfield (Figure 1). Holocene estuarine deposits, Holocene stream deposits, eolian sands, and artificial fill are widely present in the region (Helley and Lajoie, 1979) and are the geologic materials of greatest concern. Six major faults capable of producing large earthquakes cross the study area, including the San Andreas, Rodgers Creek, Hayward, West Napa, Concord, and Green Valley faults (Figure 1).

  3. Boron Derivatives of 3-Methylpyrazole.

    DTIC Science & Technology

    1984-12-01

    AD-A14$ 988 BORON DERIVRTIYES OF 3 -IETHYLPYRRZOLECU) KENTUCKY UNIV i/i LEXINGTON DEPT OF CHEMISTRY K NIEDENZU ET AL. DEC 84 UK/DC/TR- 5 N8@814-83-K...REPORT DOCUMENTATION PAGE BEFORE CO.!?OVE~r;G FORM UK/DC/TR- 5 I - -_ E. ’and Subtitle) OF 21-P R & PZRIOD COVER=~ BORON DERIVATIVES OF 3 -METHYLPYRAZOLE...pathways for the latter process. In addition, the compounds 4 ,4 ,8,8-tetrabromo- and 4 ,4 ,8 ,8-tetrakis( 3 -methylpyrazole-l-yl)-l, 5 (7)-dimethyl

  4. Boron analysis and boron imaging in biological materials for Boron Neutron Capture Therapy (BNCT).

    PubMed

    Wittig, Andrea; Michel, Jean; Moss, Raymond L; Stecher-Rasmussen, Finn; Arlinghaus, Heinrich F; Bendel, Peter; Mauri, Pier Luigi; Altieri, Saverio; Hilger, Ralf; Salvadori, Piero A; Menichetti, Luca; Zamenhof, Robert; Sauerwein, Wolfgang A G

    2008-10-01

    Boron Neutron Capture Therapy (BNCT) is based on the ability of the stable isotope 10B to capture neutrons, which leads to a nuclear reaction producing an alpha- and a 7Li-particle, both having a high biological effectiveness and a very short range in tissue, being limited to approximately one cell diameter. This opens the possibility for a highly selective cancer therapy. BNCT strongly depends on the selective uptake of 10B in tumor cells and on its distribution inside the cells. The chemical properties of boron and the need to discriminate different isotopes make the investigation of the concentration and distribution of 10B a challenging task. The most advanced techniques to measure and image boron are described, both invasive and non-invasive. The most promising approach for further investigation will be the complementary use of the different techniques to obtain the information that is mandatory for the future of this innovative treatment modality.

  5. High fluence boron implantation into polyimide

    NASA Astrophysics Data System (ADS)

    Vacík, J.; Hnatowicz, V.; Červená, J.; Peřina, V.; Popok, V.; Odzhaev, V.; Fink, D.

    1999-01-01

    100 keV B + ions are implanted at high fluences into polyimide and the boron depth distributions are measured by the neutron depth profiling technique. Subsequently the implanted samples are annealed isochronally to determine the diffusional, trapping and detrapping behaviour of the boron atoms. The boron depth profiles of as-implanted samples differ significantly from those predicted by TRIM code. Pronounced inward and outward profile tails point at increased mobility and redistribution of boron atoms after implantation. Thermal annealing to the temperatures below 150°C does not change the total boron content in 1 μm thick surface layer and the boron depth profiles as well. For higher annealing temperatures a continuous desorption and significant redistribution of boron atoms is observed.

  6. 14. VIEW OF NORTHSOUTH ROAD WHICH PARALLELS ROAD TO HATCH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. VIEW OF NORTH-SOUTH ROAD WHICH PARALLELS ROAD TO HATCH ADIT (FEATURE B-28). NOTE MODERN 'LAY DOWN' FENCE ON ROAD. ROAD LIES TO THE WEST OF THE HATCH ADIT AND PHOTOGRAPH IS VIEW TO THE SOUTH. (OCTOBER, 1995) - Nevada Lucky Tiger Mill & Mine, East slope of Buckskin Mountain, Paradise Valley, Humboldt County, NV

  7. Method of separating boron isotopes

    SciTech Connect

    Jensen, R.J.; Cluff, C.L.; Hayes, J.K.; Thorne, J.M.

    1984-05-08

    A method of boron isotope enrichment involving the isotope preferential photolysis of (2-chloroethenyl)dichloroborane as the feed material. The photolysis can readily be achieved with CO/sub 2/ laser radiation and using fluences significantly below those required to dissociate BCl/sub 3/.

  8. Structure of boron nitride nanotubes

    SciTech Connect

    Buranova, Yu. S. Kulnitskiy, B. A.; Perezhogin, I. A.; Blank, V. D.

    2015-01-15

    The crystallographic structure of boron nitride nanotubes has been investigated. Various defects that may arise during nanotube synthesis are revealed by electron microscopy. Nanotubes with different numbers of walls and different diameters are modeled by molecular dynamics methods. Structural features of single-wall nanotubes are demonstrated. The causes of certain defects in multiwall nanotubes are indicated.

  9. Method of separating boron isotopes

    DOEpatents

    Jensen, R.J.; Thorne, J.M.; Cluff, C.L.

    1981-01-23

    A method of boron isotope enrichment involving the isotope preferential photolysis of (2-chloroethenyl)-dichloroborane as the feed material. The photolysis can readily by achieved with CO/sub 2/ laser radiation and using fluences significantly below those required to dissociate BCl/sub 3/.

  10. Method of separating boron isotopes

    DOEpatents

    Jensen, Reed J.; Thorne, James M.; Cluff, Coran L.; Hayes, John K.

    1984-01-01

    A method of boron isotope enrichment involving the isotope preferential photolysis of (2-chloroethenyl)dichloroborane as the feed material. The photolysis can readily be achieved with CO.sub.2 laser radiation and using fluences significantly below those required to dissociate BCl.sub.3.

  11. Structure of boron nitride nanotubes

    NASA Astrophysics Data System (ADS)

    Buranova, Yu. S.; Kulnitskiy, B. A.; Perezhogin, I. A.; Blank, V. D.

    2015-01-01

    The crystallographic structure of boron nitride nanotubes has been investigated. Various defects that may arise during nanotube synthesis are revealed by electron microscopy. Nanotubes with different numbers of walls and different diameters are modeled by molecular dynamics methods. Structural features of single-wall nanotubes are demonstrated. The causes of certain defects in multiwall nanotubes are indicated.

  12. Seerley Road Fire Site

    EPA Pesticide Factsheets

    A barn caught fire at on Seerley Road, Indianapolis. Five storage drums believed to contain metallic potassium were involved in the fire. EPA will perform additional sampling as part of removal operations and safe offsite transportation.

  13. Rapid road repair vehicle

    DOEpatents

    Mara, Leo M.

    1998-01-01

    Disclosed is a rapid road repair vehicle capable of moving over a surface to be repaired at near normal posted traffic speeds to scan for and find an the high rate of speed, imperfections in the pavement surface, prepare the surface imperfection for repair by air pressure and vacuum cleaning, applying a correct amount of the correct patching material to effect the repair, smooth the resulting repaired surface, and catalog the location and quality of the repairs for maintenance records of the road surface. The rapid road repair vehicle can repair surface imperfections at lower cost, improved quality, at a higher rate of speed than was was heretofor possible, with significantly reduced exposure to safety and health hazards associated with this kind of road repair activities in the past.

  14. Rapid road repair vehicle

    DOEpatents

    Mara, L.M.

    1998-05-05

    Disclosed is a rapid road repair vehicle capable of moving over a surface to be repaired at near normal posted traffic speeds to scan for and find at the high rate of speed, imperfections in the pavement surface, prepare the surface imperfection for repair by air pressure and vacuum cleaning, applying a correct amount of the correct patching material to effect the repair, smooth the resulting repaired surface, and catalog the location and quality of the repairs for maintenance records of the road surface. The rapid road repair vehicle can repair surface imperfections at lower cost, improved quality, at a higher rate of speed than was not heretofor possible, with significantly reduced exposure to safety and health hazards associated with this kind of road repair activities in the past. 2 figs.

  15. [A review on road ecology].

    PubMed

    Li, Yuehui; Hu, Yuanman; Li, Xiuzhen; Xiao, Duning

    2003-03-01

    Roads are a widespread and increasing feature of most landscapes, and have great ecological effects, e.g., increased mortality of animals and plants and habitat loss from road construction, alteration of the physical and chemical environment, and changes in roadsides vegetation. The great impact on animal population includes road-kills, limiting population, road avoidance causing home arrange shift, modification of movement pattern and barrier effect subdividing habitat and populations. Roads alter landscape spatial pattern and interrupt horizontal ecological flows strongly. These impacts can be assayed by indices of road density, road-effect zone and road location. Furthermore, important applications of road ecology to planning, conservation and management are essential and potential. Road ecology presents us a surprising frontier of ecology.

  16. Boron neutron capture therapy for cancer

    SciTech Connect

    Barth, R.E.; Soloway, A.H. ); Fairchild, R.G. State Univ. of New York, Stony Brook )

    1990-10-01

    Boron neutron capture therapy (BNCT) bring together two components that when kept separate have only minor effects on normal cells. The first component is a stable isotope of boron (boron 10) that can be concentrated in tumor cells. The second is a beam of low-energy neutrons that produces short-range radiation when absorbed, or captured, by the boron. The combination of these two conditions at the site of a tumor releases intense radiation that can destroy malignant tissues. BNCT is based on the nuclear reaction that occurs when boron 10 is irradiated with an absorbs neutrons. The neutrons that it takes up are called thermal, or slow, neutrons. They are of such low energy that they cause little tissue damage as compared with other forms of radiation such as protons, gamma rays and fast neutrons. When an atom of boron 10 captures a neutron, an unstable isotope, boron 11, forms. The boron 11 instantly fissions, yielding lithium 7 nuclei and energetic alpha particles. These heavy particles, which carry 2.79 million electron volts of energy, are a highly lethal form of radiation. If the treatment proceeds as intended, the destructive effects of the capture reaction would occur primarily in those cancer cells that have accumulated boron 10. Normal cells with low concentrations of boron would be spared.

  17. Chronic boron exposure and human semen parameters.

    PubMed

    Robbins, Wendie A; Xun, Lin; Jia, Juan; Kennedy, Nola; Elashoff, David A; Ping, Liu

    2010-04-01

    Boron found as borates in soil, food, and water has important industrial and medical applications. A panel reviewing NTP reproductive toxicants identified boric acid as high priority for occupational studies to determine safe versus adverse reproductive effects. To address this, we collected boron exposure/dose measures in workplace inhalable dust, dietary food/fluids, blood, semen, and urine from boron workers and two comparison worker groups (n=192) over three months and determined correlations between boron and semen parameters (total sperm count, sperm concentration, motility, morphology, DNA breakage, apoptosis and aneuploidy). Blood boron averaged 499.2 ppb for boron workers, 96.1 and 47.9 ppb for workers from high and low environmental boron areas (p<0.0001). Boron concentrated in seminal fluid. No significant correlations were found between blood or urine boron and adverse semen parameters. Exposures did not reach those causing adverse effects published in animal toxicology work but exceeded those previously published for boron occupational groups.

  18. 1. NORTHWEST SIDE AND SOUTHWEST FRONT. Looking east. Edwards ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. NORTHWEST SIDE AND SOUTHWEST FRONT. Looking east. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Firing Control Building, Test Area 1-100, northeast end of Test Area 1-100 Road, Boron, Kern County, CA

  19. 1. MINUTEMAN SILO INTERIOR (MARCH 1961). Looking down a silo. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. MINUTEMAN SILO INTERIOR (MARCH 1961). Looking down a silo. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Missile Silo Type, Test Area 1-100, northeast end of Test Area 1-100 Road, Boron, Kern County, CA

  20. 4. INSTRUMENT ROOM,INTERIOR, MAIN SPACE. Looking northeast. Edwards Air ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. INSTRUMENT ROOM,INTERIOR, MAIN SPACE. Looking northeast. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Firing Control Building, Test Area 1-100, northeast end of Test Area 1-100 Road, Boron, Kern County, CA

  1. Reductive Insertion of Elemental Chalcogens into Boron-Boron Multiple Bonds.

    PubMed

    Braunschweig, Holger; Dellermann, Theresa; Ewing, William C; Kramer, Thomas; Schneider, Christoph; Ullrich, Stefan

    2015-08-24

    The syntheses of sulfur- and selenium-bridged cyclic compounds containing boron stabilized by N-heterocyclic carbenes (NHCs) have been achieved by the reductive insertion of elemental chalcogens into boron-boron multiple bonds. The three pairs of bonding electrons between the boron atoms in the triply bonded diboryne enabled six-electron reduction reactions, resulting in the formation of [2.2.1]-bicyclic systems wherein bridgehead boron atoms are spanned by three chalcogen bridges. A similar reaction using a diborene (boron-boron double bond) resulted in the reductive transfer of both pairs of bonding electrons to three sulfur atoms, yielding a NHC-stabilized trisulfidodiborolane. The demonstration of these six- and four-electron reductions lends support to the presence of three and two pairs of bonding electrons between the boron atoms of the diboryne and diborene, respectively, a fact that may be useful in future discussions on bond order.

  2. Synthesis of boron nitride nanotubes by boron ink annealing

    NASA Astrophysics Data System (ADS)

    Li, Lu Hua; Chen, Ying; Glushenkov, Alexey M.

    2010-03-01

    Ball-milling and annealing is one effective method for the mass production of boron nitride nanotubes (BNNTs). We report that the method has been modified to a boron (B) ink annealing method. In this new process, the nanosize ball-milled B particles are mixed with metal nitrate in ethanol to form an ink-like solution, and then the ink is annealed in nitrogen-containing gas to form nanotubes. The new method greatly enhances the yield of BNNTs, giving a higher density of nanotubes. These improvements are caused by the addition of metal nitrate and ethanol, both of which can strongly boost the nitriding reaction, as revealed by thermogravimetric analysis. The size and structure of BNNTs can be controlled by varying the annealing conditions. This high-yield production of BNNTs in large quantities enables the large-scale application of BNNTs.

  3. Synthesis of boron nitride nanotubes by boron ink annealing.

    PubMed

    Li, Lu Hua; Chen, Ying; Glushenkov, Alexey M

    2010-03-12

    Ball-milling and annealing is one effective method for the mass production of boron nitride nanotubes (BNNTs). We report that the method has been modified to a boron (B) ink annealing method. In this new process, the nanosize ball-milled B particles are mixed with metal nitrate in ethanol to form an ink-like solution, and then the ink is annealed in nitrogen-containing gas to form nanotubes. The new method greatly enhances the yield of BNNTs, giving a higher density of nanotubes. These improvements are caused by the addition of metal nitrate and ethanol, both of which can strongly boost the nitriding reaction, as revealed by thermogravimetric analysis. The size and structure of BNNTs can be controlled by varying the annealing conditions. This high-yield production of BNNTs in large quantities enables the large-scale application of BNNTs.

  4. Jaguar Procedures for Detonation Behavior of Explosives Containing Boron

    NASA Astrophysics Data System (ADS)

    Stiel, L. I.; Baker, E. L.; Capellos, C.

    2009-12-01

    The Jaguar product library was expanded to include boron and boron containing products by analysis of Available Hugoniot and static volumetric data to obtain constants of the Murnaghan relationships for the components. Experimental melting points were also utilized to obtain the constants of the volumetric relationships for liquid boron and boron oxide. Detonation velocities for HMX—boron mixtures calculated with these relationships using Jaguar are in closer agreement with literature values at high initial densities for inert (unreacted) boron than with the completely reacted metal. These results indicate that the boron does not react near the detonation front or that boron mixtures exhibit eigenvalue detonation behavior (as shown by some aluminized explosives), with higher detonation velocities at the initial points. Analyses of calorimetric measurements for RDX—boron mixtures indicate that at high boron contents the formation of side products, including boron nitride and boron carbide, inhibits the detonation properties of the formulation.

  5. Longitudinal Splitting of Boron Nitride Nanotubes for the Facile Synthesis of High Quality Boron Nitride Nanoribbons

    DTIC Science & Technology

    2011-05-24

    Boron Nitride Nanotubes for the Facile Synthesis of High Quality Boron Nitride Nanoribbons Kris J. Erickson,†,‡,§ Ashley...We report the synthesis of BNNRs through the potassium-intercalation-induced longitudinal splitting of boron nitride nanotubes (BNNTs). This facile...COVERED 00-00-2011 to 00-00-2011 4. TITLE AND SUBTITLE Longitudinal Splitting of Boron Nitride Nanotubes for the Facile Synthesis of High

  6. Method for preparing boron-carbide articles

    DOEpatents

    Benton, S.T.; Masters, D.R.

    1975-10-21

    The invention is directed to the preparation of boron carbide articles of various configurations. A stoichiometric mixture of particulate boron and carbon is confined in a suitable mold, heated to a temperature in the range of about 1250 to 1500$sup 0$C for effecting a solid state diffusion reaction between the boron and carbon for forming the boron carbide (B$sub 4$C), and thereafter the resulting boron-carbide particles are hot-pressed at a temperature in the range of about 1800 to 2200$sup 0$C and a pressure in the range of about 1000 to 4000 psi for densifying and sintering the boron carbide into the desired article.

  7. Prediction of boron carbon nitrogen phase diagram

    NASA Astrophysics Data System (ADS)

    Yao, Sanxi; Zhang, Hantao; Widom, Michael

    We studied the phase diagram of boron, carbon and nitrogen, including the boron-carbon and boron-nitrogen binaries and the boron-carbon-nitrogen ternary. Based on the idea of electron counting and using a technique of mixing similar primitive cells, we constructed many ''electron precise'' structures. First principles calculation is performed on these structures, with either zero or high pressures. For the BN binary, our calculation confirms that a rhmobohedral phase can be stablized at high pressure, consistent with some experimental results. For the BCN ternary, a new ground state structure is discovered and an Ising-like phase transition is suggested. Moreover, we modeled BCN ternary phase diagram and show continuous solubility from boron carbide to the boron subnitride phase.

  8. A new class of boron nanotube.

    PubMed

    Wang, Jing; Liu, Ying; Li, You-Cheng

    2009-12-07

    The configurations, stability and electronic structures of a new class of boron sheet and related boron nanotubes are predicted within the framework of density functional theory. This boron sheet is sparser than those of recent proposals. Our theoretic results show that the stable boron sheet remains flat and is metallic. There are bands similar to the pi-bands in graphite near the Fermi level. Stable nanotubes with various diameters and chiral vectors can be rolled from the sheet. Within our study, only the thin (8, 0) nanotube with a band gap of 0.44 eV is semiconducting, while all the other thicker boron nanotubes are metallic, independent of their chirality. It indicates the possibility, in the design of nanodevices, to control the electronic transport properties of the boron nanotube through the diameter.

  9. Initial boronization of PBX-M using ablation of solid boronized probes

    SciTech Connect

    Kugel, H.W.; Hirooka, Y.; Kaita, R.; Kaye, S.; Khandagle, M.; Timberlake, J.; Bell, R.; England, A.; Isler, R.; Okabayashi, M.; Paul, S.; Takahashi, H.; Tighe, W.; von Goeler, S.; Post-Zwicker, A.P.; Jones, S.

    1993-05-01

    The initial boronization of PBX-M was performed using the sequential ablation of two types of solid target probes. Probe-1 in a mushroom shape consisted of a 10.7% boronized 2-D C-C composite containing 3.6 g of boron in a B{sub 4}C binder. Probe-2 in a rectangular shape consisted of an 86% boronized graphite felt composite containing 19.5 g of 40 {mu} boron particles. After boronization with Probe-1, the loop voltage during 1 MW neutral beam heated plasmas decreased 27% and volt-sec consumption decreased 20%. Strong peripheral spectral lines from low-Z elements decreased by factors of about 5. The central oxygen density decreased 15--20%. The total radiated power during neutral beam injection decreased by 43%. Probe-2 boronization exhibited improved operating conditions similar to Probe-1, but for some parameters, a smaller percentage change occurred due to the residual boron from the previous boronization using Probe-1. The ablation rates of both probes were consistent with front face temperatures at or slightly above the boron melting point. These results confirm the effectiveness of the solid target boronization (STB) technique as a real-time impurity control method for replenishing boron depositions without the use of hazardous borane compounds.

  10. Initial boronization of PBX-M using ablation of solid boronized probes

    SciTech Connect

    Kugel, H.W.; Hirooka, Y.; Kaita, R.; Kaye, S.; Khandagle, M. . Inst. of Plasma and Fusion Research); Timberlake, J.; Bell, R.; England, A.; Isler, R.; Okabayashi, M.; Paul, S.; Takahashi, H.; Tighe, W.; von Goeler, S.; Post-Zwicker, A.P. ); Jones, S. )

    1993-05-01

    The initial boronization of PBX-M was performed using the sequential ablation of two types of solid target probes. Probe-1 in a mushroom shape consisted of a 10.7% boronized 2-D C-C composite containing 3.6 g of boron in a B[sub 4]C binder. Probe-2 in a rectangular shape consisted of an 86% boronized graphite felt composite containing 19.5 g of 40 [mu] boron particles. After boronization with Probe-1, the loop voltage during 1 MW neutral beam heated plasmas decreased 27% and volt-sec consumption decreased 20%. Strong peripheral spectral lines from low-Z elements decreased by factors of about 5. The central oxygen density decreased 15--20%. The total radiated power during neutral beam injection decreased by 43%. Probe-2 boronization exhibited improved operating conditions similar to Probe-1, but for some parameters, a smaller percentage change occurred due to the residual boron from the previous boronization using Probe-1. The ablation rates of both probes were consistent with front face temperatures at or slightly above the boron melting point. These results confirm the effectiveness of the solid target boronization (STB) technique as a real-time impurity control method for replenishing boron depositions without the use of hazardous borane compounds.

  11. Stereodivergent Olefination of Enantioenriched Boronic Esters

    PubMed Central

    Armstrong, Roly J.; García‐Ruiz, Cristina; Myers, Eddie L.

    2016-01-01

    Abstract A stereodivergent coupling reaction between vinyl halides and boronic esters is described. This coupling process proceeds without a transition‐metal catalyst, instead proceeding by electrophilic selenation or iodination of a vinyl boronate complex followed by stereospecific syn or anti elimination. Chiral, nonracemic boronic esters could be coupled with complete enantiospecificity. The process enables the highly stereoselective synthesis of either the E or Z alkene from a single isomer of a vinyl coupling partner. PMID:27958668

  12. Synthesis, Properties, and Applications Of Boron Nitride

    NASA Technical Reports Server (NTRS)

    Pouch, John J.; Alterovitz, Samuel A.

    1993-01-01

    Report describes synthesis, properties, and applications of boron nitride. Especially in thin-film form. Boron nitride films useful as masks in x-ray lithography; as layers for passivation of high-speed microelectronic circuits; insulating films; hard, wear-resistant, protective films for optical components; lubricants; and radiation detectors. Present status of single-crystal growth of boron nitride indicates promising candidate for use in high-temperature semiconductor electronics.

  13. Dietary boron, brain function, and cognitive performance.

    PubMed Central

    Penland, J G

    1994-01-01

    Although the trace element boron has yet to be recognized as an essential nutrient for humans, recent data from animal and human studies suggest that boron may be important for mineral metabolism and membrane function. To investigate further the functional role of boron, brain electrophysiology and cognitive performance were assessed in response to dietary manipulation of boron (approximately 0.25 versus approximately 3.25 mg boron/2000 kcal/day) in three studies with healthy older men and women. Within-subject designs were used to assess functional responses in all studies. Spectral analysis of electroencephalographic data showed effects of dietary boron in two of the three studies. When the low boron intake was compared to the high intake, there was a significant (p < 0.05) increase in the proportion of low-frequency activity, and a decrease in the proportion of higher-frequency activity, an effect often observed in response to general malnutrition and heavy metal toxicity. Performance (e.g., response time) on various cognitive and psychomotor tasks also showed an effect of dietary boron. When contrasted with the high boron intake, low dietary boron resulted in significantly poorer performance (p < 0.05) on tasks emphasizing manual dexterity (studies II and III); eye-hand coordination (study II); attention (all studies); perception (study III); encoding and short-term memory (all studies); and long-term memory (study I). Collectively, the data from these three studies indicate that boron may play a role in human brain function and cognitive performance, and provide additional evidence that boron is an essential nutrient for humans. PMID:7889884

  14. Boron-10 ABUNCL Active Testing

    SciTech Connect

    Kouzes, Richard T.; Ely, James H.; Lintereur, Azaree T.; Siciliano, Edward R.

    2013-07-09

    The Department of Energy Office of Nuclear Safeguards and Security (NA-241) is supporting the project Coincidence Counting With Boron-Based Alternative Neutron Detection Technology at Pacific Northwest National Laboratory (PNNL) for the development of a 3He proportional counter alternative neutron coincidence counter. The goal of this project is to design, build and demonstrate a system based upon 10B-lined proportional tubes in a configuration typical for 3He-based coincidence counter applications. This report provides results from testing of the active mode of the General Electric Reuter-Stokes Alternative Boron-Based Uranium Neutron Coincidence Collar (ABUNCL) at Los Alamos National Laboratory using sources and fuel pins.

  15. METHOD OF PREPARING POLONIUM-BORON SOURCES

    DOEpatents

    Birden, J.H.

    1959-08-01

    An improved technique is described for preparation of a polonium-boron neutron source. A selected amount of Po-210 is vaporized into a thin walled nickel container, then the desired amcunt of boron powder is added. After sealing the container, it is heated quickly by induction heating to vaporize the Po-210 and deposit it in the still cool boron powder. The unit is then quickly cooled to prevent revaporization of the Po-210 from the boron. The build-up of neutron emission may be followed by means of a neutron counter in order to terminate the heating at the optimum level of neutron yield.

  16. Boron removal from geothermal waters by electrocoagulation.

    PubMed

    Yilmaz, A Erdem; Boncukcuoğlu, Recep; Kocakerim, M Muhtar; Yilmaz, M Tolga; Paluluoğlu, Cihan

    2008-05-01

    Most of the geothermal waters in Turkey contain extremely high concentration of boron when they are used for irrigation. The use of geothermal waters for irrigation can results in excess amount deposition of boron in soil. On the other hand, a minimal boron concentration is required for irrigational waters. In this study, electrocoagulation (EC) was selected as a treatment process for the removal of boron from thermal waters obtained from Ilica-Erzurum in Turkey. Current density (CD), pH of solution and temperature of solution were selected as operational parameters. The results showed that boron removal efficiency increased from pH 4.0 to 8.0 and decreased at pH 10.0. Although boron removal efficiency was highest at pH 8.0, energy consumption was very high at this pH value compared to other pH intervals. Boron removal efficiency reached to 95% with increasing current density from 1.5 to 6.0 mA/cm(2), but energy consumption was also increased in this interval. At higher temperatures of solution, such as 313 and 333 K, boron removal efficiency increased. At optimum conditions, boron removal efficiency in geothermal water reached up to 95%.

  17. Mineral resource of the month: boron

    USGS Publications Warehouse

    Crangle, Robert D.

    2012-01-01

    The article offers information on the mineral, boron. Boron compounds, particularly borates, have more commercial applications than its elemental relative which is a metalloid. Making up the 90% of the borates that are used worldwide are colemanite, kernite, tincal, and ulexite. The main borate deposits are located in the Mojave Desert of the U.S., the Tethyan belt in southern Asia, and the Andean belt of South America. Underground and surface mining are being used in gathering boron compounds. INSETS: Fun facts;Boron production and consumption.

  18. Boron containing multilayer coatings and method of fabrication

    DOEpatents

    Makowiecki, D.M.; Jankowski, A.F.

    1997-09-23

    Hard coatings are fabricated from multilayer boron/boron carbide, boron carbide/cubic boron nitride, and boron/boron nitride/boron carbide, and the fabrication thereof involves magnetron sputtering in a selected atmosphere. These hard coatings may be applied to tools and engine and other parts, as well to reduce wear on tribological surfaces and electronic devices. These boron coatings contain no morphological growth features. For example, the boron and boron carbide used in forming the multilayers are formed in an inert (e.g. argon) atmosphere, while the cubic boron nitride is formed in a reactive (e.g. nitrogen) atmosphere. The multilayer boron/boron carbide, and boron carbide/cubic boron nitride is produced by depositing alternate layers of boron, cubic boron nitride or boron carbide, with the alternate layers having a thickness of 1 nanometer to 1 micrometer, and at least the interfaces of the layers may be of a discrete or a blended or graded composition. 6 figs.

  19. Making Microscopic Cubes Of Boron

    NASA Technical Reports Server (NTRS)

    Faulkner, Joseph M.

    1993-01-01

    Production of finely divided cubes of boron involves vacuum-deposition technology and requires making of template. Template supports pattern of checkered squares 25 micrometers on side, which are etched 25 micrometers into template material. Template coasted uniformly with paralyene or some similar vacuum coating with low coefficient of adhesion. Intended application to solid rocket fuels, explosives, and pyrotechnics; process used for other applications, from manufacture of pharmaceuticals to processing of nuclear materials.

  20. Conduction mechanism in boron carbide

    NASA Technical Reports Server (NTRS)

    Wood, C.; Emin, D.

    1984-01-01

    Electrical conductivity, Seebeck-coefficient, and Hall-effect measurements have been made on single-phase boron carbides, B(1-x)C(x), in the compositional range from 0.1 to 0.2 X, and between room temperature and 1273 K. The results indicate that the predominant conduction mechanism is small-polaron hopping between carbon atoms at geometrically inequivalent sites.

  1. View southwest along Brown Road showing residential and commercial buildings ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View southwest along Brown Road showing residential and commercial buildings on the north and south sides of the road - Brooklyn Green, North Green, South Green, & West Green, parts of Brown Road, Canterbury Road (Route 169), Hartford Road (Route 6), Hyde Road, Pomfret Road (Route 169), Prince Hill Road, Providence Road (Route 6), Wauregan Road (Routes 169 & 205), & Wolf Den Road, Brooklyn, Windham County, CT

  2. 1:00 PM EST: EPA, CARB Media Call to Provide Update on Recent Actions on Volkswagen

    EPA Pesticide Factsheets

    WASHINGTON - The U.S. Environmental Protection Agency and the California Air Resources Board will host a media call at 1:00 p.m. EST today, Monday, November 2, to provide an update on the agencies' actions on Volkswagen.

  3. Energy Landscape of Fullerene Materials: A Comparison of Boron to Boron Nitride and Carbon

    NASA Astrophysics Data System (ADS)

    de, Sandip; Willand, Alexander; Amsler, Maximilian; Pochet, Pascal; Genovese, Luigi; Goedecker, Stefan

    2011-06-01

    Using the minima hopping global geometry optimization method on the density functional potential energy surface we show that the energy landscape of boron clusters is glasslike. Larger boron clusters have many structures which are lower in energy than the cages. This is in contrast to carbon and boron nitride systems which can be clearly identified as structure seekers. The differences in the potential energy landscape explain why carbon and boron nitride systems are found in nature whereas pure boron fullerenes have not been found. We thus present a methodology which can make predictions on the feasibility of the synthesis of new nanostructures.

  4. Boron coating on boron nitride coated nuclear fuels by chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Durmazuçar, Hasan H.; Gündüz, Güngör

    2000-12-01

    Uranium dioxide-only and uranium dioxide-gadolinium oxide (5% and 10%) ceramic nuclear fuel pellets which were already coated with boron nitride were coated with thin boron layer by chemical vapor deposition to increase the burn-up efficiency of the fuel during reactor operation. Coating was accomplished from the reaction of boron trichloride with hydrogen at 1250 K in a tube furnace, and then sintering at 1400 and 1525 K. The deposited boron was identified by infrared spectrum. The morphology of the coating was studied by using scanning electron microscope. The plate, grainy and string (fiber)-like boron structures were observed.

  5. Rapid road repair vehicle

    DOEpatents

    Mara, Leo M.

    1999-01-01

    Disclosed are improvments to a rapid road repair vehicle comprising an improved cleaning device arrangement, two dispensing arrays for filling defects more rapidly and efficiently, an array of pre-heaters to heat the road way surface in order to help the repair material better bond to the repaired surface, a means for detecting, measuring, and computing the number, location and volume of each of the detected surface imperfection, and a computer means schema for controlling the operation of the plurality of vehicle subsystems. The improved vehicle is, therefore, better able to perform its intended function of filling surface imperfections while moving over those surfaces at near normal traffic speeds.

  6. 24. OLD TIOGA ROAD VIEW, NOW MAY LAKE ROAD , ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    24. OLD TIOGA ROAD VIEW, NOW MAY LAKE ROAD , AT SNOW FLAT. MOUNT HOFFMAN AT CENTER REAR. LOOKING NW. GIS: N-37 49 34.6 / W-119 29 58.2 - Tioga Road, Between Crane Flat & Tioga Pass, Yosemite Village, Mariposa County, CA

  7. The symmetry of the boron buckyball and a related boron nanotube

    NASA Astrophysics Data System (ADS)

    Gonzalez Szwacki, N.; Tymczak, C. J.

    2010-07-01

    We investigate the symmetry of the boron buckyball and a related boron nanotube. Using large-scale ab initio calculations up to second-order Møller-Plesset perturbation theory, we have determined unambiguously the equilibrium geometry/symmetry of two structurally related boron clusters: the B 80 fullerene and the finite-length (5 0) boron nanotube. The B 80 cluster was found to have the same symmetry, Ih, as the C 60 molecule since its 20 additional boron atoms are located exactly at the centers of the 20 hexagons. Additionally, we also show that the (5 0) boron nanotube does not suffer from atomic buckling and its symmetry is D5d instead of C5v as has been described by previous calculations. Therefore, we predict that all the boron nanotubes rolled from the α-sheet will be free from structural distortions, which has a significant impact on their electronic properties.

  8. Classification of road surface profiles

    SciTech Connect

    Rouillard, V.; Bruscella, B.; Sek, M.

    2000-02-01

    This paper introduces a universal classification methodology for discretely sampled sealed bituminous road profile data for the study of shock and vibrations related to the road transportation process. Data representative of a wide variety of Victorian (Australia) road profiles were used to develop a universal classification methodology with special attention to their non-Gaussian and nonstationary properties. This resulted in the design of computer software to automatically detect and extract transient events from the road spatial acceleration data as well as to identify segments of the constant RMS level enabling transients to be analyzed separately from the underlying road process. Nine universal classification parameters are introduced to describe road profile spatial acceleration based on the statistical characteristics of the transient amplitude and stationary RMS segments. Results from this study are aimed at the areas of road transport simulation as well as road surface characterization.

  9. Porphyrins for boron neutron capture therapy

    DOEpatents

    Miura, Michiko; Gabel, Detlef

    1990-01-01

    Novel compounds for treatment of brain tumors in Boron Neutron Capture Therapy are disclosed. A method for preparing the compounds as well as pharmaceutical compositions containing said compounds are also disclosed. The compounds are water soluble, non-toxic and non-labile boronated porphyrins which show significant uptake and retention in tumors.

  10. Boron Discovered in Ancient Habitable Mars Groundwater

    SciTech Connect

    Gasda, Patrick

    2016-12-13

    Boron was recently discovered in calcium-sulfate veins on Mars using the ChemCam instrument on NASA’s Curiosity Mars Rover. This is the first Mars mission to detect boron on the Red Planet. Los Alamos Post-Doctoral Student Patrick Gasda explains how this discovery helps us better understand the timescale of habitability on Mars.

  11. Boron chemicals in diagnosis and therapeutics

    PubMed Central

    Das, Bhaskar C; Thapa, Pritam; Karki, Radha; Schinke, Caroline; Das, Sasmita; Kambhampati, Suman; Banerjee, Sushanta K; Van Veldhuizen, Peter; Verma, Amit; Weiss, Louis M; Evans, Todd

    2013-01-01

    Advances in the field of boron chemistry have expanded the application of boron from material use to medicine. Boron-based drugs represent a new class of molecules that possess several biomedical applications including use as imaging agents for both optical and nuclear imaging as well as therapeutic agents with anticancer, antiviral, antibacterial, antifungal and other disease-specific activities. For example, bortezomib (Velcade®), the only drug in clinical use with boron as an active element, was approved in 2003 as a proteasome inhibitor for the treatment of multiple myeloma and non-Hodgkin’s lymphoma. Several other boron-based compounds are in various phases of clinical trials, which illustrates the promise of this approach for medicinal chemists working in the area of boron chemistry. It is expected that in the near future, several boron-containing drugs should become available in the market with better efficacy and potency than existing drugs. This article discusses the current status of the development of boron-based compounds as diagnostic and therapeutic agents in humans. PMID:23617429

  12. Boron chemicals in diagnosis and therapeutics.

    PubMed

    Das, Bhaskar C; Thapa, Pritam; Karki, Radha; Schinke, Caroline; Das, Sasmita; Kambhampati, Suman; Banerjee, Sushanta K; Van Veldhuizen, Peter; Verma, Amit; Weiss, Louis M; Evans, Todd

    2013-04-01

    Advances in the field of boron chemistry have expanded the application of boron from material use to medicine. Boron-based drugs represent a new class of molecules that possess several biomedical applications including use as imaging agents for both optical and nuclear imaging as well as therapeutic agents with anticancer, antiviral, antibacterial, antifungal and other disease-specific activities. For example, bortezomib (Velcade(®)), the only drug in clinical use with boron as an active element, was approved in 2003 as a proteasome inhibitor for the treatment of multiple myeloma and non-Hodgkin's lymphoma. Several other boron-based compounds are in various phases of clinical trials, which illustrates the promise of this approach for medicinal chemists working in the area of boron chemistry. It is expected that in the near future, several boron-containing drugs should become available in the market with better efficacy and potency than existing drugs. This article discusses the current status of the development of boron-based compounds as diagnostic and therapeutic agents in humans.

  13. Ultratough single crystal boron-doped diamond

    DOEpatents

    Hemley, Russell J [Carnegie Inst. for Science, Washington, DC ; Mao, Ho-Kwang [Carnegie Inst. for Science, Washington, DC ; Yan, Chih-Shiue [Carnegie Inst. for Science, Washington, DC ; Liang, Qi [Carnegie Inst. for Science, Washington, DC

    2015-05-05

    The invention relates to a single crystal boron doped CVD diamond that has a toughness of at least about 22 MPa m.sup.1/2. The invention further relates to a method of manufacturing single crystal boron doped CVD diamond. The growth rate of the diamond can be from about 20-100 .mu.m/h.

  14. Boron Carbides As Thermo-electric Materials

    NASA Technical Reports Server (NTRS)

    Wood, Charles

    1988-01-01

    Report reviews recent theoretical and experimental research on thermoelectric materials. Recent work with narrow-band semiconductors demonstrated possibility of relatively high thermoelectric energy-conversion efficiencies in materials withstanding high temperatures needed to attain such efficiencies. Among promising semiconductors are boron-rich borides, especially boron carbides.

  15. On the Road

    ERIC Educational Resources Information Center

    Collins, Mary Ellen

    2012-01-01

    Veteran development officers say the experience of visiting and traveling to different places or countries often feels like an endless cycle of getting lost, missing flights, and eating midnight dinners from hotel vending machines. Despite ongoing travel challenges, experienced road warriors have learned how to maximize their effectiveness,…

  16. Road-Cleaning Device

    ERIC Educational Resources Information Center

    Roman, Harry T.

    2014-01-01

    Roadways are literally soaked with petrochemical byproducts, oils, gasoline, and other volatile substances that eventually run off into sewers and end up in rivers, waterways, and other undesirable places. Can the roads be cleaned of these wastes, with their proper disposal? Can vehicles, robots, or other devices be designed that could be driven…

  17. The Road Home

    ERIC Educational Resources Information Center

    O'Shaughnessy, Molly

    2016-01-01

    "Children have the potential to create a world we cannot imagine. This is our hope." In choosing Montessori, O'Shaughnessy says that we are choosing the road less traveled. We are choosing education as an aid to life. We are choosing an approach that respects the innate and unique potential of each child and that calls upon us to serve…

  18. State of Florida 1:24,000- and 1:100,000-scale Quadrangle Index Map - Highlighting Low-Lying Areas Derived from USGS Digital Elevation Models

    USGS Publications Warehouse

    Kosovich, John J.

    2008-01-01

    In support of U.S. Geological Survey (USGS) disaster preparedness efforts, this map depicts 1:24,000- and 1:100,000-scale quadrangle footprints over a color shaded relief representation of the State of Florida. The first 30 feet of relief above mean sea level are displayed as brightly colored 5-foot elevation bands, which highlight low-elevation areas at a coarse spatial resolution. Standard USGS National Elevation Dataset (NED) 1 arc-second (nominally 30-meter) digital elevation model (DEM) data are the basis for the map, which is designed to be used at a broad scale and for informational purposes only. The NED source data for this map consists of a mixture of 30-meter- and 10-meter-resolution DEMs. The NED data were derived from the original 1:24,000-scale USGS topographic map bare-earth contours, which were converted into gridded quadrangle-based DEM tiles at a constant post spacing (grid cell size) of either 30 meters (data before the mid-1990s) or 10 meters (mid-1990s and later data). These individual-quadrangle DEMs were then converted to spherical coordinates (latitude/longitude decimal degrees) and edge-matched to ensure seamlessness. Figure 1 shows a similar representation for the entire U.S. Gulf Coast, using coarsened 30-meter NED data. Areas below sea level typically are surrounded by levees or some other type of flood-control structures. State and county boundary, hydrography, city, and road layers were modified from USGS National Atlas data downloaded in 2003. Quadrangle names, dated April, 2006, were obtained from the Federal Geographic Names Information System. The NED data were downloaded in 2004.

  19. Boronated mesophase pitch coke for lithium insertion

    NASA Astrophysics Data System (ADS)

    Frackowiak, E.; Machnikowski, J.; Kaczmarska, H.; Béguin, F.

    Boronated carbons from mesophase pitch have been used as materials for lithium storage in Li/carbon cells. Doping by boron has been realized by co-pyrolysis of coal tar pitch with the pyridine-borane complex. Amount of boron in mesocarbon microbeads (MCMB) varied from 1.4 to 1.8 wt.% affecting the texture of carbon. Optical microscopy and X-ray diffractograms have shown tendency to more disordered structure for boron-doped carbon. The values of specific reversible capacity ( x) varied from 0.7 to 1.1 depending significantly on the final temperature of pyrolysis (700-1150°C). The optimal charge/discharge performance was observed for boronated carbon heated at 1000°C.

  20. Primitive boron isotope composition of the mantle.

    PubMed

    Chaussidon, M; Marty, B

    1995-07-21

    Boron isotope ratios are homogeneous in volcanic glasses of oceanic island basalts [-9.9 +/- 1.3 per mil, relative to standard NBS 951 (defined by the National Bureau of Standards)], whereas mid-oceanic ridge basalts (MORBs) and back-arc basin basalts (BABBs) show generally higher and more variable ratios. Melts that have assimilated even small amounts of altered basaltic crust show significant variations in the boron isotope ratios. Assimilation may thus account for the higher boron ratios of MORBs and BABBs. A budget of boron between mantle and crust implies that the primitive mantle had a boron isotope ratio of -10 +/- 2 per mil and that this ratio was not fractionated significantly during the differentiation of the mantle.

  1. Recombination Activity of Iron in Boron Doped Silicon

    NASA Astrophysics Data System (ADS)

    Yli-Koski, M.; Palokangas, M.; Sokolov, V.; Storgårds, J.; Väinölä, H.; Holmberg, H.; Sinkkonen, J.

    The charge carrier lifetime in iron contaminated boron doped silicon wafers was determined by surface photovoltage, SPV, and microwave photoconductive decay, µPCD, techniques. Our results show that the charge carrier lifetime in boron doped silicon wafers depends on the boron concentration when the lifetime is limited by iron-boron pairs.

  2. Boron enrichment in martian clay.

    PubMed

    Stephenson, James D; Hallis, Lydia J; Nagashima, Kazuhide; Freeland, Stephen J

    2013-01-01

    We have detected a concentration of boron in martian clay far in excess of that in any previously reported extra-terrestrial object. This enrichment indicates that the chemistry necessary for the formation of ribose, a key component of RNA, could have existed on Mars since the formation of early clay deposits, contemporary to the emergence of life on Earth. Given the greater similarity of Earth and Mars early in their geological history, and the extensive disruption of Earth's earliest mineralogy by plate tectonics, we suggest that the conditions for prebiotic ribose synthesis may be better understood by further Mars exploration.

  3. Boron Enrichment in Martian Clay

    PubMed Central

    Nagashima, Kazuhide; Freeland, Stephen J.

    2013-01-01

    We have detected a concentration of boron in martian clay far in excess of that in any previously reported extra-terrestrial object. This enrichment indicates that the chemistry necessary for the formation of ribose, a key component of RNA, could have existed on Mars since the formation of early clay deposits, contemporary to the emergence of life on Earth. Given the greater similarity of Earth and Mars early in their geological history, and the extensive disruption of Earth's earliest mineralogy by plate tectonics, we suggest that the conditions for prebiotic ribose synthesis may be better understood by further Mars exploration. PMID:23762242

  4. Boron foils for RDDS experiment

    NASA Astrophysics Data System (ADS)

    Lipski, A. R.; Rainovski, G.; Pietralla, N.; Dewald, A.

    2008-06-01

    Application of the deposition method based on the vibrational motion of micro particles in an electrostatic field [I. Sugai, Nucl. Instr. and Meth. A 397 (1997) 81] is described for the production of isotopic 11B foils. The method proved suitable for target production of this typically brittle material when a very flat target surface was required. The goal to produce 11B targets of 160-350 μg/cm 2 was achieved by depositing the boron on a thin foil substrate, such as Nb and Sn. The coated foil was stretched flat before it was mounted on a frame.

  5. Improved Boron for Enhanced Combustion

    DTIC Science & Technology

    1990-06-01

    2, p. 74F - 80F, 1955. 11. Perry and Chilton, " Chemical Engineer ’ Handbook," McGraw-Hill, 5th Edition, 1973, and 6th Edition, 1986. 12. Levenspiel ...0., " Chemical Reaction Engineering ," Wiley & Sons, 2nd Edition, 1972. 13. Hern, R. B, and R. G. Sidall, M. W. Thring, "Flow Patterns in a Phase Change...wet chemical method, allows the use of higher solution concentrations of boron than AAS, provides better precision, and allows us to simultaneously

  6. View southeast to Canterbury Road (Route 169) showing the Israel ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View southeast to Canterbury Road (Route 169) showing the Israel Putnam Memorial - Brooklyn Green, North Green, South Green, & West Green, parts of Brown Road, Canterbury Road (Route 169), Hartford Road (Route 6), Hyde Road, Pomfret Road (Route 169), Prince Hill Road, Providence Road (Route 6), Wauregan Road (Routes 169 & 205), & Wolf Den Road, Brooklyn, Windham County, CT

  7. [Supervising road safety in Peru].

    PubMed

    Sagástegui, Freddy

    2010-06-01

    In this article some problems in road safety are described, which have been detected by the Ombudsman of Peru, as part of its role of public administration supervisor, amongst these problems we mention: lack of and inadequate elaboration of the statistics on road traffic accidents, the inconsistency of the National Council for Road Security and the lack of responsibility of the local and regional governments reflected by the lack of application of the National Plan of Road Safety. Facing this, the Ombudsman suggests that the State develops a rigorous statistical system, strengthens the National Council of Road Safety and that the different sectors of the government develop the mentioned National Plan.

  8. Can we prevent road rage?

    PubMed

    Asbridge, Mark; Smart, Reginald G; Mann, Robert E

    2006-04-01

    Road rage has become a serious concern in many countries, and preventive efforts are required. This article reviews what can be done to prevent road rage by exploring potential prevention avenues in five areas. First, legal changes aimed at increasing the penalties for road rage behavior could be instituted, drawing on models from aggressive-driving or impaired-driving laws. A second approach would involve the adoption of court programs for convicted road ragers. Third, car redesign offers a means of reducing crime through environmental design. Fourth, mass media education could be implemented to inform drivers of the risk from road rage and how to avoid situations that facilitate road rage. Finally, prevention efforts could be directed to long-term societal changes that emphasize structural modifications, such as reducing congestion on the roads, reduced driver stress, or promoting public transportation. The strengths and weaknesses of these strategies are discussed.

  9. Autoionizing states of atomic boron

    NASA Astrophysics Data System (ADS)

    Argenti, Luca; Moccia, Roberto

    2016-04-01

    We present a B -spline K -matrix method for three-active-electron atoms in the presence of a polarizable core, with which it is possible to compute multichannel single-ionization scattering states with good accuracy. We illustrate the capabilities of the method by computing the parameters of several autoionizing states of the boron atom, with S2e, 2,o2P and D2e symmetry, up to at least the 2 p2(1S) excitation threshold of the B ii parent ion, as well as selected portions of the photoionization cross section from the ground state. Our results exhibit remarkable gauge consistency, they significantly extend the existing sparse record of data for the boron atom, and they are in good agreement with the few experimental and theoretical data available in the literature. These results open the way to extend to three-active-electron systems the spectral analysis of correlated wave packets in terms of accurate scattering states that has already been demonstrated for two-electron atoms in Argenti and Lindroth [Phys. Rev. Lett. 105, 053002 (2010), 10.1103/PhysRevLett.105.053002].

  10. Road Traffic Noise

    NASA Astrophysics Data System (ADS)

    Beckenbauer, Thomas

    Road traffic is the most interfering noise source in developed countries. According to a publication of the European Union (EU) at the end of the twentieth century [1], about 40% of the population in 15 EU member states is exposed to road traffic noise at mean levels exceeding 55 dB(A). Nearly 80 million people, 20% of the population, are exposed to levels exceeding 65 dB(A) during daytime and more than 30% of the population is exposed to levels exceeding 55 dB(A) during night time. Such high noise levels cause health risks and social disorders (aggressiveness, protest, and helplessness), interference of communication and disturbance of sleep; the long- and short-term consequences cause adverse cardiovascular effects, detrimental hormonal responses (stress hormones), and possible disturbance of the human metabolism (nutrition) and the immune system. Even performance at work and school could be impaired.

  11. Simulator of Road Tunnel

    NASA Astrophysics Data System (ADS)

    Danišovič, Peter; Schlosser, František; Šrámek, Juraj; Rázga, Martin

    2015-05-01

    A Tunnel Traffic & Operation Simulator is a device of the Centre of Transport Research at the University of Žilina. The Simulator allows managing technological equipment of virtual two-tube highway tunnel, which is interconnected with simulation of vehicle traffic in tunnel. Changes of the traffic-operation states and other equipment are reflecting at the simulated traffic, as well as simulations of various emergency events in traffic initiate changes in tunnel detecting and measuring devices. It is thus possible to simulate emergency states, which can be affected by various faults of technology as well as by climatic conditions. The solutions can be found in irreplaceable experiences of Slovak road tunnel operators, changes of trafficoperation states, visualizations of operator technological display screens, technological devices labelling in order to increase operational safety of road tunnels.

  12. Boron-Loaded Silicone Rubber Scintillators

    SciTech Connect

    Bell, Z.W.; Maya, L.; Brown, G.M.; Sloop, F.V.Jr

    2003-05-12

    Silicone rubber received attention as an alternative to polyvinyltoluene in applications in which the scintillator is exposed to high doses because of the increased resistance of the rubber to the formation of blue-absorbing color centers. Work by Bowen, et al., and Harmon, et al., demonstrated their properties under gamma/x-ray irradiation, and Bell, et al. have shown their response to thermal neutrons. This last work, however, provided an example of a silicone in which both the boron and the scintillator were contained in the rubber as solutes, a formulation which led to the precipitation of solids and sublimation of the boron component. In the present work we describe a scintillator in which the boron is chemically bonded to the siloxane and so avoids the problem of precipitation and loss of boron to sublimation. Material containing up to 18% boron, by weight, was prepared, mounted on photomultipliers, and exposed to both neutron and gamma fluxes. Pulse height spectra showing the neutron and photon response were obtained, and although the light output was found to be much poorer than from samples in which boron was dissolved, the higher boron concentrations enabled essentially 100% neutron absorption in only a few millimeters' thickness of rubber.

  13. Properties of vacuum-evaporated boron films

    NASA Technical Reports Server (NTRS)

    Feakes, F.

    1973-01-01

    The work on the properties of thin boron films made by vacuum evaporation of elemental boron using an electron beam as the energy source is reported. The program aimed at characterizing the properties of vacuum evaporated films. The work was directed toward those variables considered to be important in affecting the tensile strength of the boron films. In general, the thickness of the films was less than 0.002 in. The temperature of the substrate on which the boron was condensed was found to be most important. Three distinctly different forms of boron deposit were produced. Although the transition temperature was not sharply defined, at substrate temperatures of less than approximately 600 deg C the boron deposits were amorphous to X-ray. If the substrate were highly polished, the deposits were black and mirror-like. For substrates with coefficients of thermal expansion close to that of boron, the deposits were then continuous and uncracked. The studies suggest that the potential continues to exist for film-type composites to have both high strength and high modulus.

  14. High fluence boron implantation into polymers

    NASA Astrophysics Data System (ADS)

    Vacik, J.; Cervena, J.; Fink, D.; Klett, R.; Hnatowicz, V.; Popok, V.; Odzhaev, V.

    100 keV B+ ions are implanted at high fluence into three polymers of technological importance and into a polymeric mixture, respectively. The boron depth distributions are measured by the neutron depth profiling technique. It is shown that the boron atoms redistribute after their implantation according to the nuclear (collisional) energy transfer distribution. This contrasts to low fluence implantation, where the boron atoms redistribute according to their electronic energy transfer distributions. Subsequently, the samples are annealed isochronally. The change of the boron depth profiles with annealing temperature is then evaluated to determine the diffusional, trapping and detrapping behavior of the boron atoms. At, or slightly above room temperature, intrinsic boron impurities of the examined polymer foils become mobile and getter in the ion-implanted region. At higher temperatures, the thermal desorption spectra show a nearly continuous desorption of both the implanted and gettered boron, with no pronounced desorption peaks. Due to the high polymeric destruction yield, the different polymers show little difference in their desorption behavior.

  15. Combustion synthesis of novel boron carbide

    NASA Astrophysics Data System (ADS)

    Harini, R. Saai; Manikandan, E.; Anthonysamy, S.; Chandramouli, V.; Eswaramoorthy, D.

    2013-02-01

    The solid-state boron carbide is one of the hardest materials known, ranking third behind diamond and cubic boron nitride. Boron carbide (BxCx) enriched in the 10B isotope is used as a control rod material in the nuclear industry due to its high neutron absorption cross section and other favorable physico-chemical properties. Conventional methods of preparation of boron carbide are energy intensive processes accompanied by huge loss of boron. Attempts were made at IGCAR Kalpakkam to develop energy efficient and cost effective methods to prepare boron carbide. The products of the gel combustion and microwave synthesis experiments were characterized for phase purity by XRD. The carbide formation was ascertained using finger-print spectroscopy of FTIR. Samples of pyrolized/microwave heated powder were characterized for surface morphology using SEM. The present work shows the recent advances in understanding of structural and chemical variations in boron carbide and their influence on morphology, optical and vibrational property results discussed in details.

  16. Conductivity of boron-doped polycrystalline diamond films: influence of specific boron defects

    NASA Astrophysics Data System (ADS)

    Ashcheulov, P.; Šebera, J.; Kovalenko, A.; Petrák, V.; Fendrych, F.; Nesládek, M.; Taylor, A.; Vlčková Živcová, Z.; Frank, O.; Kavan, L.; Dračínský, M.; Hubík, P.; Vacík, J.; Kraus, I.; Kratochvílová, I.

    2013-10-01

    The resistivity of boron doped polycrystalline diamond films changes with boron content in a very complex way with many unclear factors. From the large number of parameters affecting boron doped polycrystalline diamond film's conductivity we focused on the role of boron atoms inside diamond grains in terms of boron contribution to the continuum of diamond electronic states. Using a combination of theoretical and experimental techniques (plane-wave Density Functional Theory, Neutron Depth Profiling, resistivity and Hall effect measurements, Atomic Force Microscopy and Raman spectroscopy) we studied a wide range of B defect parameters - the boron concentration, location, structure, free hole concentration and mobility. The main goal and novelty of our work was to find the influence of B defects (structure, interactions, charge localisation and spins) in highly B-doped diamonds - close or above the metal-insulator transition - on the complex material charge transport mechanisms.

  17. JAGUAR Procedures for Detonation Behavior of Explosives Containing Boron

    NASA Astrophysics Data System (ADS)

    Stiel, Leonard; Baker, Ernest; Capellos, Christos

    2009-06-01

    The JAGUAR product library was expanded to include boron and boron containing products. Relationships of the Murnaghan form for molar volumes and derived properties were implemented in JAGUAR. Available Hugoniot and static volumertic data were analyzed to obtain constants of the Murnaghan relationship for solid boron, boron oxide, boron nitride, boron carbide, and boric acid. Experimental melting points were also utilized with optimization procedures to obtain the constants of the volumetric relationships for liquid boron and boron oxide. Detonation velocities for HMX - boron mixtures calculated with these relationships using JAGUAR are in closer agreement with literature values at high initial densities for inert (unreacted) boron than with the completely reacted metal. These results indicate that boron mixtures may exhibit eigenvalue detonation behavior, as observed by aluminized combined effects explosives, with higher detonation velocities than would be achieved by a classical Chapman-Jouguet detonation. Analyses of calorimetric measurements for RDX - boron mixtures indicate that at high boron contents the formation of side products, including boron nitride and boron carbide, inhibits the energy output obtained from the detonation of the formulation.

  18. Thermodynamic limitation on boron energy realization in ramjet propulsion

    NASA Astrophysics Data System (ADS)

    Gany, Alon

    2014-05-01

    This study addresses a specific boron combustion aspect, revealing that thermodynamic conditions associated with highly boron-loaded ramjet combustors, may lead to blockage of the reaction between boron and air, causing termination of the combustion process, incomplete chemical reaction, and only partial realization of the potential boron combustion energy. Sustained boron combustion may take place when the evaporation rate of the protective liquid boron oxide layer B2O3(l) on the boron particles exceeds its generation rate by the oxidation reaction, typically at temperatures above 1900-2000 K. However, if the actual partial pressure of gaseous boron oxide B2O3(g) produced in the combustion process attains the equilibrium vapor pressure of boron oxide at the conditions existing in the combustion chamber, condensation of the boron oxide to form a liquid layer on the boron particle surfaces may take place, extinguishing the particle combustion by blocking the reaction between the boron and the surrounding oxidizing gas. The study predicts conditions for blockage and incomplete boron combustion over a range of chamber pressures and temperatures. This effect may be characteristic to combustors employing boron-containing fuels, but may not be encountered in the combustion of individual boron particles in air.

  19. Tweets on the Road

    PubMed Central

    Lenormand, Maxime; Tugores, Antònia; Colet, Pere; Ramasco, José J.

    2014-01-01

    The pervasiveness of mobile devices, which is increasing daily, is generating a vast amount of geo-located data allowing us to gain further insights into human behaviors. In particular, this new technology enables users to communicate through mobile social media applications, such as Twitter, anytime and anywhere. Thus, geo-located tweets offer the possibility to carry out in-depth studies on human mobility. In this paper, we study the use of Twitter in transportation by identifying tweets posted from roads and rails in Europe between September 2012 and November 2013. We compute the percentage of highway and railway segments covered by tweets in 39 countries. The coverages are very different from country to country and their variability can be partially explained by differences in Twitter penetration rates. Still, some of these differences might be related to cultural factors regarding mobility habits and interacting socially online. Analyzing particular road sectors, our results show a positive correlation between the number of tweets on the road and the Average Annual Daily Traffic on highways in France and in the UK. Transport modality can be studied with these data as well, for which we discover very heterogeneous usage patterns across the continent. PMID:25141161

  20. Experiments on Washboard Road

    NASA Astrophysics Data System (ADS)

    Morris, Stephen; Taberlet, Nicolas; McElwaine, James; Dalziel, Stuart

    2007-03-01

    Granular surfaces to develop lateral ripples (so-called ``washboard" or ``corrugated" road) under the action of rolling wheels. Similar ripples are observed on railroad tracks and many other rolling, load bearing surfaces. Our aim was to investigate this instability of the flat road surface from the point of view of driven, dissipative granular dynamics. We report the results of both laboratory experiments and soft-particle direct numerical simulations. The experiment consisted of a rotating table 60 cm in radius with a thick layer of sand forming a roadbed around the circumference. A 6 cm radius hard rubber wheel, with a support stationary in the lab frame, rolled on the sand layer. We varied the speed of the table, the details of the grains and the suspension of the wheel. The ripple pattern appears as small patches of travelling waves which eventually spread to the entire circumference. The ripples drift slowly in the driving direction. Interesting secondary dynamics of the saturated ripples were observed, as well as various ripple creation and destruction events. The wavelength of the ripples can be quantized by the finite circumference of the road. All of these effects are captured qualitatively by 2D soft particle simulations in which a disk rolls over a 2D bed of polydisperse particles in a periodic box.

  1. Evaluation of the anaesthetic properties and tolerance of 1:100,000 articaine versus 1:100,000 lidocaine. A comparative study in surgery of the lower third molar

    PubMed Central

    Barona-Dorado, Cristina; Martín-Arés, María; Cortés-Bretón-Brinkman, Jorge; Martínez-González, José M.

    2012-01-01

    Objectives: To evaluate the anaesthetic properties and tolerance of articaine versus lidocaine at equal vasoconstrictor concentration. Study Design: A total of 96 male and female patients who underwent surgical treatment of the lower third molar participated. Patients were randomly assigned to articaine hydrochloride with epinephrine 1:100,000 and lidocaine hydrochloride with epinephrine 1:100,000. The variables analysed were latency period, duration of anaesthetic effect, tolerance and adverse reactions. Results: Both the latency period and the duration of anaesthetic effect were greater for articaine, although the differences were not statistically significant. Latency: mean difference of 2.70 ± 2.12 minutes (95%CI of -1.51 minutes - 6.92 minutes). Duration: mean difference of -33 minutes 5 seconds ± 31 minutes (95% CI -1 hour 35 minutes - 29 minutes). There were 4 adverse events that did not require the patients to be withdrawn from the study. Conclusions: The anaesthetics in this study have very similar properties for use in surgery and have demonstrated a good safety and tolerability profile Key words: Articaine, lidocaine, vasoconstrictor, adverse reactions. PMID:22143691

  2. X-ray diffraction study of boron produced by pyrolysis of boron tribromide

    NASA Astrophysics Data System (ADS)

    Rosenberg, David

    The goal of this research was to determine the composition of boron deposits produced by pyrolysis of boron tribromide, and to use the results to (a) determine the experimental conditions (reaction temperature, etc.) necessary to produce alpha-rhombohedral boron and (b) guide the development/refinement of the pyrolysis experiments such that large, high purity crystals of alpha-rhombohedral boron can be produced with consistency. Developing a method for producing large, high purity alpha-rhombohedral boron crystals is of interest because such crystals could potentially be used to achieve an alpha-rhombohedral boron based neutron detector design (a solid-state detector) that could serve as an alternative to existing neutron detector technologies. The supply of neutron detectors in the United States has been hampered for a number of years due to the current shortage of helium-3 (a gas used in many existing neutron detector technologies); the development of alternative neutron detector technology such as an alpha-rhombohedral boron based detector would help provide a more sustainable supply of neutron detectors in this country. In addition, the prospect/concept of an alpha-rhombohedral boron based neutron detector is attractive because it offers the possibility of achieving a design that is smaller, longer life, less power consuming, and potentially more sensitive than existing neutron detectors. The main difficulty associated with creating an alpha-rhombohedral boron based neutron detector is that producing large, high purity crystals of alpha-rhombohedral boron is extremely challenging. Past researchers have successfully made alpha-rhombohedral boron via a number of methods, but no one has developed a method for consistently producing large, high purity crystals. Alpha-rhombohedral boron is difficult to make because it is only stable at temperatures below around 1100-1200 °C, its formation is very sensitive to impurities, and the conditions necessary for its

  3. Watershed boundaries and digital elevation model of Oklahoma derived from 1:100,000-scale digital topographic maps

    USGS Publications Warehouse

    Cederstrand, J.R.; Rea, A.H.

    1995-01-01

    This document provides a general description of the procedures used to develop the data sets included on this compact disc. This compact disc contains watershed boundaries for Oklahoma, a digital elevation model, and other data sets derived from the digital elevation model. The digital elevation model was produced using the ANUDEM software package, written by Michael Hutchinson and licensed from the Centre for Resource and Environmental Studies at The Australian National University. Elevation data (hypsography) and streams (hydrography) from digital versions of the U.S. Geological Survey 1:100,000-scale topographic maps were used by the ANUDEM package to produce a hydrologically conditioned digital elevation model with a 60-meter cell size. This digital elevation model is well suited for drainage-basin delineation using automated techniques. Additional data sets include flow-direction, flow-accumulation, and shaded-relief grids, all derived from the digital elevation model, and the hydrography data set used in producing the digital elevation model. The watershed boundaries derived from the digital elevation model have been edited to be consistent with contours and streams from the U.S. Geological Survey 1:100,000-scale topographic maps. The watershed data set includes boundaries for 11-digit Hydrologic Unit Codes (watersheds) within Oklahoma, and 8-digit Hydrologic Unit Codes (cataloging units) outside Oklahoma. Cataloging-unit boundaries based on 1:250,000-scale maps outside Oklahoma for the Arkansas, Red, and White River basins are included. The other data sets cover Oklahoma, and where available, portions of 1:100,000-scale quadrangles adjoining Oklahoma.

  4. Boron Fullerenes: An Electronic Structure Study

    NASA Astrophysics Data System (ADS)

    Sadrzadeh, Arta; Pupysheva, Olga; Boustani, Ihsan; Yakobson, Boris

    2008-03-01

    Using ab initio calculations, we study electronic structure and frequency modes of B80, a member of boron fullerene family made from boron isomorphs of carbon fullerenes with additional atoms in the centers of hexagons. We also investigate geometrical and electronic structural properties of double-rings with various diameters, which are important as building blocks of boron nanotubes, and as the most stable clusters among the studied isomers with no more than 36 atoms. Double-rings also appear as building blocks of B80. Furthermore, we investigate the possibility of further stabilizing some of fullerenes by depleting them.

  5. Crystallization of Beryllium-Boron Metallic Glasses

    SciTech Connect

    Jankowski, A F; Wall, M A; Nieh, T G

    2002-02-14

    Prior studies of evaporation and sputter deposition show that the grain size of pure beryllium can be dramatically refined through the incorporation of metal impurities. Recently, the addition of boron at a concentration greater than 11% is shown to serve as a glassy phase former in sputter deposited beryllium. Presently, thermally induced crystallization of the beryllium-boron metallic glass is reported. The samples are characterized during an in-situ anneal treatment with bright field imaging and electron diffraction using transmission electron microscopy. A nanocrystalline structure evolves from the annealed amorphous phase and the crystallization temperature is affected by the boron concentration.

  6. Boron-10 Lined Proportional Counter Wall Effects

    SciTech Connect

    Siciliano, Edward R.; Kouzes, Richard T.

    2012-05-01

    The Department of Energy Office of Nuclear Safeguards (NA-241) is supporting the project 'Coincidence Counting With Boron-Based Alternative Neutron Detection Technology' at Pacific Northwest National Laboratory (PNNL) for development of an alternative neutron coincidence counter. The goal of this project is to design, build and demonstrate a boron-lined proportional tube based system in the configuration of a coincidence counter. This report provides information about how variations in proportional counter radius and gas pressure in a typical coincident counter design might affect the observed signal from boron-lined tubes. A discussion comparing tubes to parallel plate counters is also included.

  7. Boron Nitride Nanoribbons: Synthesis and Future Directions

    NASA Astrophysics Data System (ADS)

    Gibb, Ashley; Erikson, Kris; Sinitskii, Alex; Rousseas, Michael; Alem, Nasim; Tour, James; Zettl, Alex

    2012-02-01

    Boron Nitride Nanoribbons (BNNR) have been theorized to have many interesting electrical and magnetic properties and edge states, but these characteristics have not been experimentally verified due to challenges in synthesis and purification. We have produced BNNRs by longitudinally splitting boron nitride nanotubes (BNNT) using potassium vapor as an intercalant. Due to the strong interactions between boron nitride sheets, separation of nanoribbons from their parent tubes is challenging. We have used various solvent systems to assist with separation of the ribbons with the goal of probing their properties.

  8. Developments in boron magnetic resonance imaging (MRI)

    SciTech Connect

    Schweizer, M.

    1995-11-01

    This report summarizes progress during the past year on maturing Boron-11 magnetic resonance imaging (MRI) methodology for noninvasive determination of BNCT agents (BSH) spatially in time. Three major areas are excerpted: (1) Boron-11 MRI of BSH distributions in a canine intracranial tumor model and the first human glioblastoma patient, (2) whole body Boron-11 MRI of BSH pharmacokinetics in a rat flank tumor model, and (3) penetration of gadolinium salts through the BBB as a function of tumor growth in the canine brain.

  9. Acoustic Analysis for a Steam Dome and Pipings of a 1,100 MWe-Class Boiling Water Reactor

    SciTech Connect

    Yasumi, Kitajima; Masanobu, Watanabe; Keiji, Matsunaga; Tsuyoshi, Hagiwara

    2006-07-01

    For the integrity evaluation of steam dryers in up-rated nuclear power plants, we have applied acoustic analysis to a nuclear power plant steam dome and main steam pipings. We have selected a 1,100 MWe-class boiling water reactor as a subject of the analysis. We have constructed a three-dimensional finite element model, and conducted acoustic analyses. The analysis result suggested that the origin of steam pressure pulsation in high frequency range was due to vortex shedding at standpipes. (authors)

  10. Characterization of boron tolerant bacteria isolated from a fly ash dumping site for bacterial boron remediation.

    PubMed

    Edward Raja, Chellaiah; Omine, Kiyoshi

    2013-08-01

    Boron is an essential micronutrient for plants, but can above certain concentrations be toxic to living organisms. A major environmental concern is the removal of boron from contaminated water and fly ash. For this purpose, the samples were collected from a fly ash dumping site, Nagasaki prefecture, Japan. The chemical characteristics and heavy metal concentration of the samples were performed by X-ray fluorescent analysis and leaching test. For bacterial analysis, samples were collected in sterile plastic sheets and isolation was carried out by serial dilution method. The boron tolerant isolates that showed values of maximum inhibitory concentration toward boron ranging from 100 to 260 mM level were screened. Based on 16S rRNA sequencing and phylogenetic analysis, the isolates were most closely related to the genera Bacillus, Lysinibacillus, Microbacterium and Ralstonia. The boron tolerance of these strains was also associated with resistant to several heavy metals, such as As (III), Cr (VI), Cd, Cu, Pb, Ni, Se (III) and Zn. Indeed, these strains were arsenic oxidizing bacteria confirmed by silver nitrate test. These strains exhibited their salt resistances ranging from 4 to 15 % were determined in Trypticase soy agar medium. The boron tolerant strains were capable of removing 0.1-2.0 and 2.7-3.7 mg l(-1) boron from the medium and fly ash at 168 h. Thus, we have successfully identified the boron tolerant and removal bacteria from a fly ash dumping site for boron remediation.

  11. Borocaptate sodium: a potential boron delivery compound for boron neutron capture therapy evaluated in dogs with spontaneous intracranial tumors.

    PubMed Central

    Kraft, S L; Gavin, P R; DeHaan, C E; Leathers, C W; Bauer, W F; Miller, D L; Dorn, R V

    1992-01-01

    Borocaptate sodium (Na2B12H11SH) is a boron-carrying compound under consideration for use in boron neutron capture therapy. The biodistribution of boron from borocaptate sodium administration will partly determine boron neutron capture therapy efficacy and normal tissue radiation tolerance. The biodistribution of boron was determined in 30 dogs with spontaneous intracranial tumors at 2, 6, or 12 hr after intravenous borocaptate sodium infusion. Blood and tissue boron concentrations were measured using inductively coupled plasma atomic emission spectroscopy. Mean tumor boron concentration (mean +/- standard error) was 35.9 +/- 4.6 (n = 15), 22.5 +/- 6.0 (n = 9), and 7.0 +/- 1.1 micrograms of boron per g (n = 6) at 2, 6, and 12 hr, respectively, after borocaptate sodium infusion. Peritumor boron concentrations were elevated above that of normal brain in half of the dogs. Normal brain boron concentration (mean +/- standard error) was 4.0 +/- 0.5, 2.0 +/- 0.4, and 2.0 +/- 0.3 micrograms of boron per g at 2, 6, and 12 hr after infusion, respectively. Some cranial and systemic tissues, and blood, had high boron concentration relative to tumor tissue. Geometric dose sparing should partly offset these relatively high normal tissue and blood concentrations. Borocaptate sodium biodistribution is favorable because tumor boron concentrations of recommended magnitude for boron neutron capture therapy were obtained and there was a high tumor-to-normal brain boron concentration ratio. PMID:1465427

  12. Annealing characteristics of amorphous silicon alloy solar cells irradiated with 1.00 MeV protons

    NASA Technical Reports Server (NTRS)

    Abdulaziz, Salman S.; Woodyard, James R.

    1991-01-01

    Amorphous Si:H and amorphous Si sub x, Ge sub (1-x):H solar cells were irradiated with 1.00 MeV proton fluences in the range of 1.00E14 to 1.25E15 cm (exp -2). Annealing of the short circuit current density was studied at 0, 22, 50, 100, and 150 C. Annealing times ranged from an hour to several days. The measurements confirmed that annealing occurs at 0 C and the initial characteristics of the cells are restored by annealing at 200 C. The rate of annealing does not appear to follow a simple nth order reaction rate model. Calculations of the short-circuit current density using quantum efficiency measurements and the standard AM1.5 global spectrum compare favorably with measured values. It is proposed that the degradation in J sub sc with irradiation is due to carrier recombination through the fraction of D (o) states bounded by the quasi-Fermi energies. The time dependence of the rate of annealing of J sub sc does appear to be consistent with the interpretation that there is a thermally activated dispersive transport mechanism which leads to the passivation of the irradiation induced defects.

  13. Paleontologic Database for the Guadalupe Peak 1:100,000 Quadrangle: A Prototype for the National Paleontologic Database, Paleodata

    USGS Publications Warehouse

    Wardlaw, Bruce R.

    2008-01-01

    This report is a compilation of most of the known fossil locality data from Guadalupe Peak 1:100,000 quadrangle, West Texas. The data represent several major collection efforts over the past century by the Smithsonian Institution, the American Museum of Natural History, and the U.S. Geological Survey. This dataset is not meant to be all inclusive but instead is an attempt to pull together the vast amount of paleontologic data originally collected by Girty (1908) and King (1948), much of which is unpublished and (or) poorly located. The author visited most of the major fossil collection sites to collect for conodonts on a ten-year program funded by the Smithsonian Institution for collaborative research with Richard E. Grant. Guadalupe Mountains National Park occupies the northern part of the quadrangle, and the Park Service has been very helpful over the years in compiling the data and relocating the collection sites. This dataset serves as the prototype for the National Paleontologic Database, part of the National Geologic Map Database Project. The database is intended to be indexed to 1:100,000 quadrangles of the U.S. The minimum number of fields and information within those fields is shown in the report.

  14. Detailed sections from auger holes in the Elizabethtown 1:100,000-scale map sheet, North Carolina

    USGS Publications Warehouse

    Weems, Robert E.; Lewis, William C.; Murray, Joseph H.; Queen, David B.; Grey, Jeffrey B.; DeJong, Benjamin D.

    2011-01-01

    The Elizabethtown 1:100,000 quadrangle is in the west-central part of the Coastal Plain of southeastern North Carolina. The Coastal Plain, in this region, consists mostly of unlithified sediments that range in age from Late Cretaceous to Holocene. These sediments lie with profound unconformity on complexly deformed metamorphic and igneous rocks similar to rocks found immediately to the west in the Piedmont province. Coastal Plain sediments generally dip gently to the southeast or south and reach a maximum thickness of about 850 feet (ft) in the extreme southeast part of the map area. The gentle southerly and southeasterly dip is disrupted in several areas by faulting. The U.S. Geological Survey recovered one core and augered 196 research test holes in the Elizabethtown 1:100,000 quadrangle to supplement sparse outcrop data in the map area. The recovered sediments were studied and data from these sediments recorded to determine the lithologic characteristics, spatial distribution, and temporal framework of the represented Coastal Plain stratigraphic units. These test holes were critical for accurately determining the distribution of major geologic units and the position of unit boundaries. The detailed descriptions of the subsurface data can be used by geologists, hydrologists, engineers, and community planners to provide a detailed shallow-subsurface stratigraphic framework for the Elizabethtown map region.

  15. Methodology used to produce an encoded 1:100,000-scale digital hydrographic data layer for the Pacific Northwest

    USGS Publications Warehouse

    Fisher, B.J.

    1996-01-01

    The U.S. Geological Survey (USGS) has produced a River Reach File data layer for the Pacific Northwest for use in water-resource management applications. The Pacific Northwest (PNW) River Reach Files, a geo-referenced river reach data layer at 1:100,000-scale, are encoded with the U.S. Environmental Protection Agency"s (EPA) reach numbers. The encoding was a primary task of the River Reach project, because EPA"s reach identifiers are also an integral hydrologic component in a regional Northwest Environmental Data Base-an ongoing effort by Federal and State agencies to compile information on reach-specific resources on rivers in Oregon, Idaho, Washington, and western Montana. A unique conflation algorithm was developed by the USGS to transfer the EPA reach codes and other meaningful attributes from the 1:250,000-scale EPA TRACE graphic files to the PNW Reach Files. The PNW Reach Files also were designed so that reach-specific information upstream or downstream from a point in the stream network could be extracted from feature attribute tables or from a Geographic Information System. This report documents the methodology used to create this 1:100,000-scale hydrologic data layer.

  16. New approach to obtain boron selective emitters

    SciTech Connect

    Moehlecke, A.; Luque, A.

    1994-12-31

    Selective emitters, used in high efficiency solar cells, need a series of oxidations and photolithographic steps that render the process more expensive. In this paper, a new way to make selective emitters using boron is presented. The main feature of this approach is to save oxide growths and photolithographic processes and it is based on the property of boron doped silicon surfaces to be resistant to anisotropic etchings like the one performed during the texturization. Using this characteristic of boron emitter surfaces, the authors can obtain a highly doped emitter under metal grid and simultaneously a shield to avoid texture on these surfaces. First cells were processed and short wavelength response of p{sup +}nn{sup +} solar cells was enhanced by using lightly doped boron emitters in the uncovered area.

  17. Boron Neutron Capture Therapy - A Literature Review

    PubMed Central

    Nedunchezhian, Kavitaa; Thiruppathy, Manigandan; Thirugnanamurthy, Sarumathi

    2016-01-01

    Boron Neutron Capture Therapy (BNCT) is a radiation science which is emerging as a hopeful tool in treating cancer, by selectively concentrating boron compounds in tumour cells and then subjecting the tumour cells to epithermal neutron beam radiation. BNCT bestows upon the nuclear reaction that occurs when Boron-10, a stable isotope, is irradiated with low-energy thermal neutrons to yield α particles (Helium-4) and recoiling lithium-7 nuclei. A large number of 10 Boron (10B) atoms have to be localized on or within neoplastic cells for BNCT to be effective, and an adequate number of thermal neutrons have to be absorbed by the 10B atoms to maintain a lethal 10B (n, α) lithium-7 reaction. The most exclusive property of BNCT is that it can deposit an immense dose gradient between the tumour cells and normal cells. BNCT integrates the fundamental focusing perception of chemotherapy and the gross anatomical localization proposition of traditional radiotherapy. PMID:28209015

  18. Boron-Filled Hybrid Carbon Nanotubes.

    PubMed

    Patel, Rajen B; Chou, Tsengming; Kanwal, Alokik; Apigo, David J; Lefebvre, Joseph; Owens, Frank; Iqbal, Zafar

    2016-07-27

    A unique nanoheterostructure, a boron-filled hybrid carbon nanotube (BHCNT), has been synthesized using a one-step chemical vapor deposition process. The BHCNTs can be considered to be a novel form of boron carbide consisting of boron doped, distorted multiwalled carbon nanotubes (MWCNTs) encapsulating boron nanowires. These MWCNTs were found to be insulating in spite of their graphitic layered outer structures. While conventional MWCNTs have great axial strength, they have weak radial compressive strength, and do not bond well to one another or to other materials. In contrast, BHCNTs are shown to be up to 31% stiffer and 233% stronger than conventional MWCNTs in radial compression and have excellent mechanical properties at elevated temperatures. The corrugated surface of BHCNTs enables them to bond easily to themselves and other materials, in contrast to carbon nanotubes (CNTs). BHCNTs can, therefore, be used to make nanocomposites, nanopaper sheets, and bundles that are stronger than those made with CNTs.

  19. Boron-Filled Hybrid Carbon Nanotubes

    PubMed Central

    Patel, Rajen B.; Chou, Tsengming; Kanwal, Alokik; Apigo, David J.; Lefebvre, Joseph; Owens, Frank; Iqbal, Zafar

    2016-01-01

    A unique nanoheterostructure, a boron-filled hybrid carbon nanotube (BHCNT), has been synthesized using a one-step chemical vapor deposition process. The BHCNTs can be considered to be a novel form of boron carbide consisting of boron doped, distorted multiwalled carbon nanotubes (MWCNTs) encapsulating boron nanowires. These MWCNTs were found to be insulating in spite of their graphitic layered outer structures. While conventional MWCNTs have great axial strength, they have weak radial compressive strength, and do not bond well to one another or to other materials. In contrast, BHCNTs are shown to be up to 31% stiffer and 233% stronger than conventional MWCNTs in radial compression and have excellent mechanical properties at elevated temperatures. The corrugated surface of BHCNTs enables them to bond easily to themselves and other materials, in contrast to carbon nanotubes (CNTs). BHCNTs can, therefore, be used to make nanocomposites, nanopaper sheets, and bundles that are stronger than those made with CNTs. PMID:27460526

  20. Boron dose determination for BNCT using Fricke and EPR dosimetry

    SciTech Connect

    Wielopolski, L.; Ciesielski, B.

    1995-02-01

    In Boron Neutron Capture Therapy (BNCT) the dominant dose delivered to the tumor is due to {alpha} and {sup 7}Li charged particles resulting from a neutron capture by {sup 10}B and is referred to herein as the boron dose. Boron dose is directly attributable to the following two independent factors, one boron concentration and the neutron capture energy dependent cross section of boron, and two the energy spectrum of the neutrons that interact with boron. The neutron energy distribution at a given point is dictated by the incident neutron energy distribution, the depth in tissue, geometrical factors such as beam size and patient`s dimensions. To account for these factors can be accommodated by using Monte Carlo theoretical simulations. However, in conventional experimental BNCT dosimetry, e.g., using TLDs or ionization chambers, it is only possible to estimate the boron dose. To overcome some of the limitations in the conventional dosimetry, modifications in ferrous sulfate dosimetry (Fricke) and Electron Paramagnetic Resonance (EPR) dosimetry in alanine, enable to measure specifically boron dose in a mixed gamma neutron radiation fields. The boron dose, in either of the dosimeters, is obtained as a difference between measurements with boronated and unboronated dosimeters. Since boron participates directly in the measurements, the boron dosimetry reflects the true contribution, integral of the neutron energy spectrum with boron cross section, of the boron dose to the total dose. Both methods are well established and used extensively in dosimetry, they are presented briefly here.

  1. Boron

    SciTech Connect

    Cozen, L.F. )

    1991-05-01

    This paper reports that borate minerals and refined borates are used extensively for the manufacture of vitreous materials such as insulation and textile fiberglasses, borosilicate glass, and porcelain enamels and frits. In North America, these applications are estimated to account for over 54% of the borate consumption. Other substantial uses are in soaps and detergents, metallurgy, fire retardants, industrial biocides, agriculture, and various miscellaneous applications. Reported domestic borate consumption in 1990 was estimated by the U.S. Bureau of Mines to be 320 000 metric tons B{sub 2}O{sub 3} versus 354 000 metric tons B{sub 2}O{sub 3} in 1989. Consumption is projected to remain essentially static in 1991. Imports were estimated by the Bureau to be 50 000 metric tons B{sub 2}O{sub 3} in 1990. Exports of boric acid and refined borates were approximately 650 000 metric tons of product, a 15 000 metric ton increase from the 1989 level. This increase partially offsets the drop in the 1990 consumption level.

  2. Aerial photographic interpretation of lineaments and faults in late Cenozoic deposits in the eastern parts of the Saline Valley 1:100, 000 quadrangle, Nevada and California, and the Darwin Hills 1:100, 000 quadrangle, California

    SciTech Connect

    Reheis, M.C.

    1991-09-01

    Faults and fault-related lineaments in Quaternary and late Tertiary deposits in the southern part of the Walker Lane are potentially active and form patterns that are anomalous compared to those in most other areas of the Great Basin. Two maps at a scale of 1:100,000 summarize information about lineaments and faults in the area around and southwest of the Death Valley-Furnace Creek fault system based on extensive aerial-photo interpretation, limited field interpretation, limited field investigations, and published geologic maps. There are three major fault zones and two principal faults in the Saline Valley and Darwin Hills 1:100,000 quadrangles. (1) The Death Valley-Furnace Creek fault system and (2) the Hunter Mountain fault zone are northwest-trending right-lateral strike-slip fault zones. (3) The Panamint Valley fault zone and associated Towne Pass and Emigrant faults are north-trending normal faults. The intersection of the Hunter Mountain and Panamint Valley fault zones is marked by a large complex of faults and lineaments on the floor of Panamint Valley. Additional major faults include (4) the north-northwest-trending Ash Hill fault on the west side of Panamint Valley, and (5) the north-trending range-front Tin Mountain fault on the west side of the northern Cottonwood Mountains. The most active faults at present include those along the Death Valley-Furnace Creek fault system, the Tin Mountain fault, the northwest and southeast ends of the Hunter Mountain fault zone, the Ash Hill fault, and the fault bounding the west side of the Panamint Range south of Hall Canyon. Several large Quaternary landslides on the west sides of the Cottonwood Mountains and the Panamint Range apparently reflect slope instability due chiefly to rapid uplift of these ranges. 16 refs.

  3. Combustion Behavior of Free Boron Slurry Droplets,

    DTIC Science & Technology

    2014-09-26

    Shockwaves 11, 189. Faeth, G.M. (1984). Status of boron combustion research. AFOSR Specialists Meeting on Boron Combustion, June, 1984. Friedman, R...containing water. Combust. Explosion and Shockwaves 17,9. Glassman, I., Williams, F.A., and Antaki, P. (1982). A physica] and chemical interpretation...temperature environment. Combust. Explosion and Shockwaves 15, 691. Johns, J.W.C. (1961) The absorption spectrum of BOz. Can. J. Phy§. 39, 1738. Kaskan, W.E

  4. Formose reaction controlled by boronic acid compounds

    PubMed Central

    Imai, Toru; Michitaka, Tomohiro

    2016-01-01

    Formose reactions were carried out in the presence of low molecular weight and macromolecular boronic acid compounds, i.e., sodium phenylboronate (SPB) and a copolymer of sodium 4-vinylphenylboronate with sodium 4-styrenesulfonate (pVPB/NaSS), respectively. The boronic acid compounds provided different selectivities; sugars of a small carbon number were formed favorably in the presence of SPB, whereas sugar alcohols of a larger carbon number were formed preferably in the presence of pVPB/NaSS. PMID:28144337

  5. Large diameter carbon-boron fiber

    NASA Technical Reports Server (NTRS)

    Veltri, R. D.; Jacob, B. A.; Galasso, F. S.

    1975-01-01

    Investigations concerned with a development of large-diameter carbon fibers are considered, taking into account the employment of vapor deposition techniques. In the experiments a carbon monofilament substrate is used together with reacting gases which consist of combinations of hydrogen, methane, and boron trichloride. It is found that the described approach can be used to obtain a large-diameter carbon filament containing boron. The filament has reasonable strength and modulus properties.

  6. Abrasive slurry composition for machining boron carbide

    DOEpatents

    Duran, E.L.

    1984-11-29

    An abrasive slurry particularly suited for use in drilling or machining boron carbide consists essentially of a suspension of boron carbide and/or silicon carbide grit in a carrier solution consisting essentially of a dilute solution of alkylaryl polyether alcohol in octyl alcohol. The alkylaryl polyether alcohol functions as a wetting agent which improves the capacity of the octyl alcohol for carrying the grit in suspension, yet without substantially increasing the viscosity of the carrier solution.

  7. Abrasive slurry composition for machining boron carbide

    DOEpatents

    Duran, Edward L.

    1985-01-01

    An abrasive slurry particularly suited for use in drilling or machining boron carbide consists essentially of a suspension of boron carbide and/or silicon carbide grit in a carrier solution consisting essentially of a dilute solution of alkylaryl polyether alcohol in octyl alcohol. The alkylaryl polyether alcohol functions as a wetting agent which improves the capacity of the octyl alcohol for carrying the grit in suspension, yet without substantially increasing the viscosity of the carrier solution.

  8. Boronate-tau mediated uptake in neurons.

    PubMed

    Pérez, Mar; Cuadros, Raquel; Pallas-Bazarra, Noemi; García, Carlos; Langa, Elena; Jurado-Arjona, Jerónimo; Hernández, Félix; Avila, Jesús

    2014-01-01

    We modified tau protein with boronic acid to facilitate its delivery into non neural or neural cultured cells lacking tau protein. Our results indicate that the incorporated tau promotes the formation of cytoplasmic extensions in non-neuronal cells, as well as the appearance of neurites in cultured tau knockout hippocampal neurons. In addition, boronated tau is incorporated into hippocampal neurons of tau knockout mice after intracranial injection in vivo. These findings describe a novel method to deliver exogenous tau protein into cells.

  9. Amorphous boron nitride at high pressure

    NASA Astrophysics Data System (ADS)

    Durandurdu, Murat

    2016-06-01

    The pressure-induced phase transformation in hexagonal boron nitrite and amorphous boron nitrite is studied using ab initio molecular dynamics simulations. The hexagonal-to-wurtzite phase transformation is successfully reproduced in the simulation with a transformation mechanism similar to one suggested in experiment. Amorphous boron nitrite, on the other hand, gradually transforms to a high-density amorphous phase with the application of pressure. This phase transformation is irreversible because a densified amorphous state having both sp3 and sp2 bonds is recovered upon pressure release. The high-density amorphous state mainly consists of sp3 bonds and its local structure is quite similar to recently proposed intermediate boron nitrite phases, in particular tetragonal structure (P42/mnm), rather than the known the wurtzite or cubic boron nitrite due to the existence of four membered rings and edge sharing connectivity. On the basis of this finding we propose that amorphous boron nitrite might be best candidate as a starting structure to synthesize the intermediate phase(s) at high pressure and temperature (probably below 800 °C) conditions.

  10. Synthesis of borophenes: Anisotropic, two-dimensional boron polymorphs.

    PubMed

    Mannix, Andrew J; Zhou, Xiang-Feng; Kiraly, Brian; Wood, Joshua D; Alducin, Diego; Myers, Benjamin D; Liu, Xiaolong; Fisher, Brandon L; Santiago, Ulises; Guest, Jeffrey R; Yacaman, Miguel Jose; Ponce, Arturo; Oganov, Artem R; Hersam, Mark C; Guisinger, Nathan P

    2015-12-18

    At the atomic-cluster scale, pure boron is markedly similar to carbon, forming simple planar molecules and cage-like fullerenes. Theoretical studies predict that two-dimensional (2D) boron sheets will adopt an atomic configuration similar to that of boron atomic clusters. We synthesized atomically thin, crystalline 2D boron sheets (i.e., borophene) on silver surfaces under ultrahigh-vacuum conditions. Atomic-scale characterization, supported by theoretical calculations, revealed structures reminiscent of fused boron clusters with multiple scales of anisotropic, out-of-plane buckling. Unlike bulk boron allotropes, borophene shows metallic characteristics that are consistent with predictions of a highly anisotropic, 2D metal.

  11. 25. White Plains Road Bridge in foreground; Unionport Road Bridge ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    25. White Plains Road Bridge in foreground; Unionport Road Bridge in background. Van Nest, Bronx Co., NY. Sec. 4207, MP 12.75./78. - Northeast Railroad Corridor, Amtrak Route between New Jersey/New York & New York/Connecticut State Lines, New York County, NY

  12. The effect of boron deficiency on gene expression and boron compartmentalization in sugarbeet

    Technology Transfer Automated Retrieval System (TEKTRAN)

    NIP5, BOR1, NIP6, and WRKY6 genes were investigated for their role in boron deficiency in sugar beet, each with a proposed role in boron use in model plant species. All genes showed evidence of polymorphism in fragment size and gene expression in the target genomic DNA and cDNA libraries, with no co...

  13. Spectromicroscopy of boron for the optimization of boron neutron capture therapy (BNCT) for cancer

    NASA Astrophysics Data System (ADS)

    Gilbert, B.; Redondo, J.; Baudat, P.-A.; Lorusso, G. F.; Andres, R.; Van Meir, E. G.; Brunet, J.-F.; Hamou, M.-F.; Suda, T.; Mercanti, Delio; Ciotti, M. Teresa; Droubay, T. C.; Tonner, B. P.; Perfetti, P.; Margaritondo, M.; DeStasio, Gelsomina

    1998-10-01

    We used synchrotron spectromicroscopy to study the microscopic distribution of boron in rat brain tumour and healthy tissue in the field of boron neutron capture therapy (BNCT). The success of this experimental cancer therapy depends on the preferential uptake of ? in tumour cells after injection of a boron compound (in our case ?, or BSH). With the Mephisto (microscope à emission de photoélectrons par illumination synchrotronique de type onduleur) spectromicroscope, high-magnification imaging and chemical analysis was performed on brain tissue sections from a rat carrying an implanted brain tumour and the results were compared with inductively coupled plasma-atomic emission spectroscopy (ICP-AES) detection of boron in bulk tissue. Boron was found to have been taken up more favourably by regions of tumour rather than healthy tissue, but the resulting boron distribution in the tumour was inhomogeneous. The results demonstrate that Mephisto can perform microchemical analysis of tissue sections, detect and localize the presence of boron with submicron spatial resolution. The application of this technique to boron in brain tissue can therefore be used to evaluate the current efforts to optimize BNC therapy.

  14. Cross-border radon index map 1:100 000 Lausitz - Jizera - Karkonosze - Region (northern part of the Bohemian Massif).

    PubMed

    Barnet, Ivan; Pacherová, Petra; Preusse, Werner; Stec, Bartosz

    2010-10-01

    The first cross-border map describing the radon (Rn) risk from bedrock was assembled in the northern part of the Bohemian Massif at a scale 1:100 000. The map covers the area of Lausitz (Germany), Karkonosze (Czech Republic and Poland) and Jizera (Czech Republic). The map is based on 818 measurements of soil gas Rn in rock types of Precambrian to Mesozoic age with variable geology. Geographic information system (GIS) processing enabled a good coincidence of soil gas Rn concentrations between data from all three countries in lithologically adjacent rock types as well as the direct correlation to georeferenced indoor Rn values, which was tested using the Czech indoor Rn data. The method of data processing can contribute to assembling the European Geogenic Radon Map.

  15. Boron site preference in ternary Ta and Nb boron silicides

    SciTech Connect

    Khan, Atta U.; Nunes, Carlos A.; Coelho, Gilberto C.; Suzuki, Paulo A.; Grytsiv, Andriy; Bourree, Francoise; Rogl, Peter F.

    2012-06-15

    X-ray single crystal (XSC) and neutron powder diffraction data (NPD) were used to elucidate boron site preference for five ternary phases. Ta{sub 3}Si{sub 1-x}B{sub x} (x=0.112(4)) crystallizes with the Ti{sub 3}P-type (space group P4{sub 2}/n) with B-atoms sharing the 8g site with Si atoms. Ta{sub 5}Si{sub 3-x} (x=0.03(1); Cr{sub 5}B{sub 3}- type) crystallizes with space group I4/mcm, exhibiting a small amount of vacancies on the 4a site. Both, Ta{sub 5}(Si{sub 1-x}B{sub x}){sub 3}, x=0.568(3), and Nb{sub 5}(Si{sub 1-x}B{sub x}){sub 3}, x=0.59(2), are part of solid solutions of M{sub 5}Si{sub 3} with Cr{sub 5}B{sub 3}-type into the ternary M-Si-B systems (M=Nb or Ta) with B replacing Si on the 8h site. The D8{sub 8}-phase in the Nb-Si-B system crystallizes with the Ti{sub 5}Ga{sub 4}-type revealing the formula Nb{sub 5}Si{sub 3}B{sub 1-x} (x=0.292(3)) with B partially filling the voids in the 2b site of the Mn{sub 5}Si{sub 3} parent type. - Graphical abstract: The crystal structures of a series of compounds have been solved from X-ray single crystal diffractometry revealing details on the boron incorporation. Highlights: Black-Right-Pointing-Pointer Structure of a series of compounds have been solved by X-ray single crystal diffractometry. Black-Right-Pointing-Pointer Ta{sub 3}(Si{sub 1-x}B{sub x}) (x=0.112) crystallizes with the Ti{sub 3}P-type, B and Si atoms randomly share the 8g site. Black-Right-Pointing-Pointer Structure of Nb{sub 5}Si{sub 3}B{sub 1-x} (x=0.292; Ti{sub 5}Ga{sub 4}-type) was solved from NPD.

  16. Feasibility of a boron loaded scintillation detector for dose measurements related to boron neutron capture therapy

    NASA Astrophysics Data System (ADS)

    Kim, Don-Soo; Egan, James J.; Kegel, Gunter H. R.; Desimone, David

    2002-04-01

    The feasibility of the use of a boron loaded scintillation detector in a head phantom for boron neutron capture therapy dose estimates was evaluated. Several monoenergetic neutron groups were produced via the ^7Li(p,n)^7Be reaction in a metallic lithium target using the Van de Graaff accelerator at University of Massachusetts Lowell. The pulse-height spectra were taken from a natural boron loaded (10205-, 304-, 407-, 507-, 570-, 702-, and 780-keV incident neutrons. The results shows that a boron loaded scintillator could be used to distinguish the doses from different radiation sources in boron neutron capture therapy. This detector may be used in the estimation of doses due to fast neutrons, alpha particles and recoil lithium from ^10B(n,α)^7Li, and photons at the same time during neutron irradiation procedures.

  17. Ceramic silicon-boron-carbon fibers from organic silicon-boron-polymers

    NASA Technical Reports Server (NTRS)

    Riccitiello, Salvatore R. (Inventor); Hsu, Ming-Ta S. (Inventor); Chen, Timothy S. (Inventor)

    1993-01-01

    Novel high strength ceramic fibers derived from boron, silicon, and carbon organic precursor polymers are discussed. The ceramic fibers are thermally stable up to and beyond 1200 C in air. The method of preparation of the boron-silicon-carbon fibers from a low oxygen content organosilicon boron precursor polymer of the general formula Si(R2)BR(sup 1) includes melt-spinning, crosslinking, and pyrolysis. Specifically, the crosslinked (or cured) precursor organic polymer fibers do not melt or deform during pyrolysis to form the silicon-boron-carbon ceramic fiber. These novel silicon-boron-carbon ceramic fibers are useful in high temperature applications because they retain tensile and other properties up to 1200 C, from 1200 to 1300 C, and in some cases higher than 1300 C.

  18. View southwest along Route Canterbury Road (Route 169) showing commercial ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View southwest along Route Canterbury Road (Route 169) showing commercial and residential buildings on the east and west sides of the road - Brooklyn Green, North Green, South Green, & West Green, parts of Brown Road, Canterbury Road (Route 169), Hartford Road (Route 6), Hyde Road, Pomfret Road (Route 169), Prince Hill Road, Providence Road (Route 6), Wauregan Road (Routes 169 & 205), & Wolf Den Road, Brooklyn, Windham County, CT

  19. Boron nitride fibers from polymer precursors

    SciTech Connect

    Wade, B.E.

    1992-12-31

    Conversion of polymer precursors to high performance boron nitride fibers as explored through a fundamental study of the mutually dependent chemical, morphological, and processing requirements in precursor polymer synthesis, formation of continuous precursor fibers, and finally thermochemical conversion to oriented boron nitride fibers. Polyborate and polyborazylene precursors were investigated. method of incorporating polyborazine in polyborate were also explored in order to stabilize the shape of polyborate fibers and to help initiate an orientable boron nitride structure. Polyborazylene, a polyborazine of fused borazine polycyclic structures was chosen for study as a precursor for boron nitride fibers because of the closeness of its structure to that of the desired turbostratic boron nitride. Both poly(ethylene oxide) and poly(methyl methacrylate) were found to be compatible with the monomer, borazine, and polyborazylenesolutions with monoglyme. They could be used to build the viscosity of solutions. However, fibers that were hand-drawn from these solutions were very sticky and quickly hydrolyzed in room atmosphere. Conversion of polyborazylene to oriented boron nitride fibers was not realized. Processable polyborates were produced by polycondensation of trimethoxyboroxine and boric acid and also by disproportionation or trimethyoxyboraxine. It was shown that the rheological characteristics of the polyborate formed could be controlled by an appropriate combination of the conversion of the monomer to polymer and the addition of a linear organic polymer as a rheological aid. Poly(methyl methacrylate) was found to be a suitable rheological aid, with a decomposition temperature that is high enough to facilitate its incorporation in the polymerizing system and low energy to be fugitive during thermochemical conversion of the polyborate to boron nitride.

  20. Scale invariance in road networks

    NASA Astrophysics Data System (ADS)

    Kalapala, Vamsi; Sanwalani, Vishal; Clauset, Aaron; Moore, Cristopher

    2006-02-01

    We study the topological and geographic structure of the national road networks of the United States, England, and Denmark. By transforming these networks into their dual representation, where roads are vertices and an edge connects two vertices if the corresponding roads ever intersect, we show that they exhibit both topological and geographic scale invariance. That is, we show that for sufficiently large geographic areas, the dual degree distribution follows a power law with exponent 2.2⩽α⩽2.4 , and that journeys, regardless of their length, have a largely identical structure. To explain these properties, we introduce and analyze a simple fractal model of road placement that reproduces the observed structure, and suggests a testable connection between the scaling exponent α and the fractal dimensions governing the placement of roads and intersections.

  1. Fatigue of boron-aluminum composites bonds and joints

    NASA Technical Reports Server (NTRS)

    Hersh, M. S.

    1973-01-01

    Study examines effects of boron filament diameter on bonds and joints in boron-aluminum composite. Data include static strength, fatigue, and dynamic moduli of elasticity. Manson-Coffin analyses and metallurgical and fracture surface evaluation were also performed.

  2. Method of manufacture of atomically thin boron nitride

    SciTech Connect

    Zettl, Alexander K

    2013-08-06

    The present invention provides a method of fabricating at least one single layer hexagonal boron nitride (h-BN). In an exemplary embodiment, the method includes (1) suspending at least one multilayer boron nitride across a gap of a support structure and (2) performing a reactive ion etch upon the multilayer boron nitride to produce the single layer hexagonal boron nitride suspended across the gap of the support structure. The present invention also provides a method of fabricating single layer hexagonal boron nitride. In an exemplary embodiment, the method includes (1) providing multilayer boron nitride suspended across a gap of a support structure and (2) performing a reactive ion etch upon the multilayer boron nitride to produce the single layer hexagonal boron nitride suspended across the gap of the support structure.

  3. [Minimally invasive cytoselective radiation therapy using boron neutron capture reaction].

    PubMed

    Nakamura, Hiroyuki

    2010-12-01

    The cell-killing effect of boron neutron capture therapy (BNCT) is due to the nuclear reaction of two essentially nontoxic species, boron-10 ((10)B) and thermal neutrons, whose destructive effect is well observed in boron-loaded tissues. High accumulation and selective delivery of boron into tumor tissue are the most important requirements to achieve efficient neutron capture therapy of cancers. This review focuses on liposomal boron delivery system (BDS) as a recent promising approach that meet these requirements for BNCT. BDS involves two strategies: (1) encapsulation of boron in the aqueous core of liposomes and (2) accumulation of boron in the liposomal bilayer. In this review, recent development of liposomal boron delivery system is summarized.

  4. Boron removal in radioactive liquid waste by forward osmosis membrane

    SciTech Connect

    Doo Seong Hwang; Hei Min Choi; Kune Woo Lee; Jei Kwon Moon

    2013-07-01

    This study investigated the treatment of boric acid contained in liquid radioactive waste using a forward osmosis membrane. The boron permeation through the membrane depends on the type of membrane, membrane orientation, pH of the feed solution, salt and boron concentration in the feed solution, and osmotic pressure of the draw solution. The boron flux begins to decline from pH 7 and increases with an increase of the osmotic driving force. The boron flux decreases slightly with the salt concentration, but is not heavily influenced by a low salt concentration. The boron flux increases linearly with the concentration of boron. No element except for boron was permeated through the FO membrane in the multi-component system. The maximum boron flux is obtained in an active layer facing a draw solution orientation of the CTA-ES membrane under conditions of less than pH 7 and high osmotic pressure. (authors)

  5. Efficient Gate-tunable light-emitting device made of defective boron nitride nanotubes: from ultraviolet to the visible

    PubMed Central

    Attaccalite, Claudio; Wirtz, Ludger; Marini, Andrea; Rubio, Angel

    2013-01-01

    Boron nitride is a promising material for nanotechnology applications due to its two-dimensional graphene-like, insulating, and highly-resistant structure. Recently it has received a lot of attention as a substrate to grow and isolate graphene as well as for its intrinsic UV lasing response. Similar to carbon, one-dimensional boron nitride nanotubes (BNNTs) have been theoretically predicted and later synthesised. Here we use first principles simulations to unambiguously demonstrate that i) BN nanotubes inherit the highly efficient UV luminescence of hexagonal BN; ii) the application of an external perpendicular field closes the electronic gap keeping the UV lasing with lower yield; iii) defects in BNNTS are responsible for tunable light emission from the UV to the visible controlled by a transverse electric field (TEF). Our present findings pave the road towards optoelectronic applications of BN-nanotube-based devices that are simple to implement because they do not require any special doping or complex growth. PMID:24060843

  6. Road safety performance indicators for the interurban road network.

    PubMed

    Yannis, George; Weijermars, Wendy; Gitelman, Victoria; Vis, Martijn; Chaziris, Antonis; Papadimitriou, Eleonora; Azevedo, Carlos Lima

    2013-11-01

    Various road safety performance indicators (SPIs) have been proposed for different road safety research areas, mainly as regards driver behaviour (e.g. seat belt use, alcohol, drugs, etc.) and vehicles (e.g. passive safety); however, no SPIs for the road network and design have been developed. The objective of this research is the development of an SPI for the road network, to be used as a benchmark for cross-region comparisons. The developed SPI essentially makes a comparison of the existing road network to the theoretically required one, defined as one which meets some minimum requirements with respect to road safety. This paper presents a theoretical concept for the determination of this SPI as well as a translation of this theory into a practical method. Also, the method is applied in a number of pilot countries namely the Netherlands, Portugal, Greece and Israel. The results show that the SPI could be efficiently calculated in all countries, despite some differences in the data sources. In general, the calculated overall SPI scores were realistic and ranged from 81 to 94%, with the exception of Greece where the SPI was relatively lower (67%). However, the SPI should be considered as a first attempt to determine the safety level of the road network. The proposed method has some limitations and could be further improved. The paper presents directions for further research to further develop the SPI.

  7. Vitiligo road map.

    PubMed

    Lee, Brian W; Schwartz, Robert A; Hercogová, Jana; Valle, Yan; Lotti, Torello M

    2012-01-01

    Vitiligo is a depigmenting disorder stemming from melanocyte loss or dysfunction. It has a complex, multifaceted etiology. We constructed a "vitiligo road map," consisting of basic science, clinical, and treatment components, in order to better portray our current understanding of vitiligo pathogenesis and reflect upon novel biomarkers and therapeutic targets for future research. The melanocyte map elaborates on the molecular processes and intracellular signaling pathways initiated by various external autocrine/paracrine factors in representing normal melanocyte homeostatic functions modulating its viability, proliferation, differentiation, dendricity, migration, and melanogenic processes. This vitiligo map identifies known inducers/triggers of vitiligo onset and progression that cultivate a microenvironment for melanocyte disappearance, real or functional. This map describes the molecular mechanisms of currently utilized clinical and experimental treatments of vitiligo that facilitate repigmentation.

  8. Silk Roads or Steppe Roads? The Silk Roads in World History.

    ERIC Educational Resources Information Center

    Christian, David

    2000-01-01

    Explores the prehistory of the Silk Roads, reexamines their structure and history in the classical era, and explores shifts in their geography in the last one thousand years. Explains that a revised understanding of the Silk Roads demonstrates how the Afro-Eurasian land mass has been linked by networks of exchange since the Bronze Age. (CMK)

  9. Microalloying Boron Carbide with Silicon to Achieve Dramatically Improved Ductility

    DTIC Science & Technology

    2014-11-18

    Microalloying Boron Carbide with Silicon to Achieve Dramatically Improved Ductility Qi An and William A. Goddard, III* Materials and Process... Boron carbide (B4C) is a hard material whose value for extended engineering applications such as body armor; is limited by its brittleness under...Plasmonics, Optical Materials, and Hard Matter Superhard materials, such as diamond, cubic boron nitride,and boron carbide (B4C), exhibit many

  10. Polyethylene/Boron Composites for Radiation Shielding Applications

    SciTech Connect

    Harrison, Courtney; Grulke, Eric; Burgett, Eric; Hertel, Nolan

    2008-01-21

    Multifunctional composites made with boron are absorbers of low energy nuetrons, and could be used for structural shielding materials. Polyethylene/boron carbide composites were fabricated using conventional polymer processing techniques, and were evaluated for mechanical and radiation shielding properties. Addition of neat boron carbide (powder and nanoparticles) to an injection molding grade HPDE showed superior mechanical properties compared to neat HDPE. Radiation shielding measurements of a 2 wt% boron carbide composite were improved over those of the neat polyethylene.

  11. Boron nitride nanotubes and nanosheets.

    PubMed

    Golberg, Dmitri; Bando, Yoshio; Huang, Yang; Terao, Takeshi; Mitome, Masanori; Tang, Chengchun; Zhi, Chunyi

    2010-06-22

    Hexagonal boron nitride (h-BN) is a layered material with a graphite-like structure in which planar networks of BN hexagons are regularly stacked. As the structural analogue of a carbon nanotube (CNT), a BN nanotube (BNNT) was first predicted in 1994; since then, it has become one of the most intriguing non-carbon nanotubes. Compared with metallic or semiconducting CNTs, a BNNT is an electrical insulator with a band gap of ca. 5 eV, basically independent of tube geometry. In addition, BNNTs possess a high chemical stability, excellent mechanical properties, and high thermal conductivity. The same advantages are likely applicable to a graphene analogue-a monatomic layer of a hexagonal BN. Such unique properties make BN nanotubes and nanosheets a promising nanomaterial in a variety of potential fields such as optoelectronic nanodevices, functional composites, hydrogen accumulators, electrically insulating substrates perfectly matching the CNT, and graphene lattices. This review gives an introduction to the rich BN nanotube/nanosheet field, including the latest achievements in the synthesis, structural analyses, and property evaluations, and presents the purpose and significance of this direction in the light of the general nanotube/nanosheet developments.

  12. Update on human health effects of boron.

    PubMed

    Nielsen, Forrest H

    2014-10-01

    In vitro, animal, and human experiments have shown that boron is a bioactive element in nutritional amounts that beneficially affects bone growth and central nervous system function, alleviates arthritic symptoms, facilitates hormone action and is associated with a reduced risk for some types of cancer. The diverse effects of boron suggest that it influences the formation and/or activity of substances that are involved in numerous biochemical processes. Several findings suggest that this influence is through the formation of boroesters in biomolecules containing cis-hydroxyl groups. These biomolecules include those that contain ribose (e.g., S-adenosylmethionine, diadenosine phosphates, and nicotinamide adenine dinucleotide). In addition, boron may form boroester complexes with phosphoinositides, glycoproteins, and glycolipids that affect cell membrane integrity and function. Both animal and human data indicate that an intake of less than 1.0mg/day inhibits the health benefits of boron. Dietary surveys indicate such an intake is not rare. Thus, increasing boron intake by consuming a diet rich in fruits, vegetables, nuts and pulses should be recognized as a reasonable dietary recommendation to enhance health and well-being.

  13. X-ray diffraction investigation of ultrafine boron nitride powders

    SciTech Connect

    Gurov, S.V.; Chukalin, V.I.; Rezchikova, T.V.; Torbov, V.J.; Troitskii, V.N.

    1986-01-01

    This paper presents an x-ray diffraction analysis of ultrafine boron nitride powders of different mean particle sizes. Diffraction spectra of the ultrafine boron nitride powders were obtained using a DRON-1 apparatus. The experimental facts are indicative of a turbostratic character of deformation of the hexagonal lattice of ultrafinely divided boron nitride.

  14. Boron-containing amino carboxylic acid compounds and uses thereof

    DOEpatents

    Kabalka, George W.; Srivastava, Rajiv R.

    2000-03-14

    Novel compounds which are useful for boron neutron capture therapy (BNCT) are disclosed. The compounds comprise a stable boron-containing group and an aminocycloalkane carboxylic acid group or a boronated acyclic hydrocarbon-linked amino carboxylic acid. Methods for synthesis of the compounds and for use of the compounds in BNCT are disclosed.

  15. Dietary boron: possible roles in human and animal physiology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Boron is a bioactive element of low molecular weight. Since discovery of the first boron biomolecule, boromycin, in 1967, several other similar biomolecules are now well-characterized. Most recently described was a bacterial cell-to-cell communication signal that requires boron, autoinducer-II. Boro...

  16. Screening of Wheat Genotypes for Boron Efficiency in Bangladesh

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A number of Bangladeshi wheat genotypes (varieties and advanced lines) have been tested for boron efficiency through sand culture experiments over two years (2007-08 & 2008-09) against two Thai check varieties ‘Fang 60’ (boron efficient) and ‘SW41’ (boron inefficient). Performances of the genotypes ...

  17. 4. General view of road with grey birch trees looking ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. General view of road with grey birch trees looking E. - Great Smoky Mountains National Park Roads & Bridges, Heintooga Round Bottom Road & Balsam Mountain Road, Between Blue Ridge Parkway & Big Cove Road, Gatlinburg, Sevier County, TN

  18. Formation of cubic boron-nitride by the reactive sputter deposition of boron

    SciTech Connect

    Jankowski, A.F.; Hayes, J.P.; Makowiecki, D.W.; McKeman, M.A.

    1997-03-01

    Boron-nitride films are synthesized by RF magnetron sputtering boron targets where the deposition parameters of gas pressure, flow and composition are varied along with substrate temperature and applied bias. The films are analyzed using Auger electron spectroscopy, transmission electron microscopy, nanoindentation, Raman spectroscopy and x-ray absorption spectroscopy. These techniques provide characterization of film composition, crystalline structure, hardness and chemical bonding, respectively. Reactive, rf-sputtering process parameters are established which lead to the growth of crystalline BN phases. The deposition of stable and adherent boron nitride coatings consisting of the cubic phase requires 400 `C substrate heating and the application of a 300 V negative bias.

  19. Infiltration processing of boron carbide-, boron-, and boride-reactive metal cermets

    DOEpatents

    Halverson, Danny C.; Landingham, Richard L.

    1988-01-01

    A chemical pretreatment method is used to produce boron carbide-, boron-, and boride-reactive metal composites by an infiltration process. The boron carbide or other starting constituents, in powder form, are immersed in various alcohols, or other chemical agents, to change the surface chemistry of the starting constituents. The chemically treated starting constituents are consolidated into a porous ceramic precursor which is then infiltrated by molten aluminum or other metal by heating to wetting conditions. Chemical treatment of the starting constituents allows infiltration to full density. The infiltrated precursor is further heat treated to produce a tailorable microstructure. The process at low cost produces composites with improved characteristics, including increased toughness, strength.

  20. Single step synthesis of nanostructured boron nitride for boron neutron capture therapy

    NASA Astrophysics Data System (ADS)

    Singh, Bikramjeet; Singh, Paviter; Kumar, Manjeet; Thakur, Anup; Kumar, Akshay

    2015-05-01

    Nanostructured Boron Nitride (BN) has been successfully synthesized by carbo-thermic reduction of Boric Acid (H3BO3). This method is a relatively low temperature synthesis route and it can be used for large scale production of nanostructured BN. The synthesized nanoparticles have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and differential thermal analyzer (DTA). XRD analysis confirmed the formation of single phase nanostructured Boron Nitride. SEM analysis showed that the particles are spherical in shape. DTA analysis showed that the phase is stable upto 900 °C and the material can be used for high temperature applications as well boron neutron capture therapy (BNCT).

  1. Longitudinal splitting of boron nitride nanotubes for the facile synthesis of high quality boron nitride nanoribbons.

    PubMed

    Erickson, Kris J; Gibb, Ashley L; Sinitskii, Alexander; Rousseas, Michael; Alem, Nasim; Tour, James M; Zettl, Alex K

    2011-08-10

    Boron nitride nanoribbons (BNNRs), the boron nitride structural equivalent of graphene nanoribbons (GNRs), are predicted to possess unique electronic and magnetic properties. We report the synthesis of BNNRs through the potassium-intercalation-induced longitudinal splitting of boron nitride nanotubes (BNNTs). This facile, scalable synthesis results in narrow (down to 20 nm), few sheet (typically 2-10), high crystallinity BNNRs with very uniform widths. The BNNRs are at least 1 μm in length with minimal defects within the ribbon plane and along the ribbon edges.

  2. Accelerator-driven boron neutron capture therapy

    NASA Astrophysics Data System (ADS)

    Edgecock, Rob

    2014-05-01

    Boron Neutron Capture Therapy is a binary treatment for certain types of cancer. It works by loading the cancerous cells with a boron-10 carrying compound. This isotope has a large cross-section for thermal neutrons, the reaction producing a lithium nucleus and alpha particle that kill the cell in which they are produced. Recent studies of the boron carrier compound indicate that the uptake process works best in particularly aggressive cancers. Most studied is glioblastoma multiforme and a trial using a combination of BNCT and X-ray radiotherapy has shown an increase of nearly a factor of two in mean survival over the state of the art. However, the main technical problem with BNCT remains producing a sufficient flux of neutrons for a reasonable treatment duration in a hospital environment. This paper discusses this issue.

  3. On the Mechanism of Boron Ignition

    NASA Technical Reports Server (NTRS)

    Keil, D. G.; Dreizin, E. L.; Felder, W.; Vicenzi, E. P.

    1997-01-01

    Boron filaments were electrically heated in air and argon/oxygen mixtures while their resistance, temperature, and radiation at the wavelengths of BO and BO2 bands were monitored. The filaments 'burned' in two distinct stages. Samples of the filaments were quenched at different times before and during the burning and analyzed using electron microscopy. The beginning of the first stage combustion characterized by a local resistance minimum, a sharp spike in boron oxide radiation emission, and a rapid rise in temperature, occurred at 1500 +/- 70 deg. C, independent of pre-heating history and oxygen content (540%) in the gas environment. The data suggest that a phase transition occurs in the filaments at this temperature that triggers stage one combustion. Significant amounts of oxygen were found inside quenched filaments. Large spherical voids formed in the boron filaments during their second stage combustion which is interpreted to indicate a crucial role for the gas dissolution processes in the combustion scenario.

  4. A small, insertable oven for boronization

    SciTech Connect

    Brouchous, D.A.; Diebold, D.A.; Doczy, M.L.

    1996-04-01

    A small insertable oven for benchmarking the boronizing characteristics of solid compounds, such as decaborane and carborane, has been developed for the Phaedrus-T tokamak. Assembly and installation of the oven are relatively easy as the oven design utilizes a Langmuir probe drive assembly, which is standard equipment on most tokamaks and allows the oven to be inserted into the tokamak without requiring a vent. Films deposited by heating carborane into the vapor state with the oven are found to be spatially nonuniform in both thickness and in the ratio of boron to carbon as compared to films deposited with trimethylboron, a gaseous compound. Overall plasma performance is not found to be greatly affected by whether decaborane, carborane or trimethylboron is used for boronization in Phaedrus-T. {copyright} {ital 1996 American Institute of Physics.} {lt}ii;010512{gt}

  5. Oxygen radical functionalization of boron nitride nanosheets.

    PubMed

    Sainsbury, Toby; Satti, Amro; May, Peter; Wang, Zhiming; McGovern, Ignatius; Gun'ko, Yurii K; Coleman, Jonathan

    2012-11-14

    The covalent chemical functionalization of exfoliated hexagonal boron-nitride nanosheets (BNNSs) is achieved by the solution-phase oxygen radical functionalization of boron atoms in the h-BN lattice. This involves a two-step procedure to initially covalently graft alkoxy groups to boron atoms and the subsequent hydrolytic defunctionalization of the groups to yield hydroxyl-functionalized BNNSs (OH-BNNSs). Characterization of the functionalized-BNNSs using HR-TEM, Raman, UV-vis, FTIR, NMR, and TGA was performed to investigate both the structure of the BNNSs and the covalent functionalization methodology. OH-BNNSs were used to prepare polymer nanocomposites and their mechanical properties analyzed. The influence of the functional groups grafted to the surface of the BNNSs is investigated by demonstrating the impact on mechanical properties of both noncovalent and covalent bonding at the interface between the nanofiller and polymer matrixes.

  6. Boron-10 Lined Proportional Counter Model Validation

    SciTech Connect

    Lintereur, Azaree T.; Siciliano, Edward R.; Kouzes, Richard T.

    2012-06-30

    The Department of Energy Office of Nuclear Safeguards (NA-241) is supporting the project “Coincidence Counting With Boron-Based Alternative Neutron Detection Technology” at Pacific Northwest National Laboratory (PNNL) for the development of an alternative neutron coincidence counter. The goal of this project is to design, build and demonstrate a boron-lined proportional tube-based alternative system in the configuration of a coincidence counter. This report discusses the validation studies performed to establish the degree of accuracy of the computer modeling methods current used to simulate the response of boron-lined tubes. This is the precursor to developing models for the uranium neutron coincidence collar under Task 2 of this project.

  7. Enhancement and retardation of thermal boron diffusion in silicon from atmospheric pressure chemical vapor deposited boron silicate glass film

    NASA Astrophysics Data System (ADS)

    Kurachi, Ikuo; Yoshioka, Kentaro

    2014-03-01

    Thermal boron diffusion into silicon from boron silicate glass (BSG) prepared by atmospheric pressure CVD (AP-CVD) has been investigated in terms of the BSG boron concentration dependence on diffusion mechanism for N-type solar cell applications. With thermal diffusion at 950 °C in N2 for 20 min, the sheet resistance of the boron-diffused layer decreases with BSG boron concentration up to approximately 4 × 1021 cm-3 at which a boron-rich layer (BRL) is formed at the surface. However, the resistance increases with BSG boron concentration when the BSG boron concentration is higher than 4 × 1021 cm-3. It is also confirmed that the diffusion depth decreases with increasing BSG boron concentration within this BSG concentration region. To clarify this mechanism, the BSG boron concentration dependence on boron diffusivity has also been studied. From extracted diffusivities, the anomalous diffusion can be explained by silicon interstitials formed owing to kick-out by diffused boron atoms and by silicon interstitial generation-degradation due to BRL formation.

  8. Boron removal by electrocoagulation and recovery.

    PubMed

    Isa, Mohamed Hasnain; Ezechi, Ezerie Henry; Ahmed, Zubair; Magram, Saleh Faraj; Kutty, Shamsul Rahman Mohamed

    2014-03-15

    This work investigated the removal of boron from wastewater and its recovery by electrocoagulation and hydrothermal mineralization methods respectively. The experimental design was developed using Box-Behnken Model. An initial study was performed based on four preselected variables (pH, current density, concentration and time) using synthetic wastewater. Response surface methodology (RSM) was used to evaluate the effect of process variables and their interaction on boron removal. The optimum conditions were obtained as pH 6.3, current density 17.4 mA/cm(2), and time 89 min. At these applied optimum conditions, 99.7% boron removal from an initial concentration of 10.4 mg/L was achieved. The process was effectively optimized by RSM with a desirability value of 1.0. The results showed that boron removal efficiency enhanced with increase in current density and treatment time. Removal efficiency also increased when pH was increased from 4 to 7 and subsequently decreased at pH 10. Adsorption kinetics study revealed that the reaction followed pseudo second order kinetic model; evidenced by high correlation and goodness of fit. Thermodynamics study showed that mechanism of boron adsorption was chemisorption and the reaction was endothermic in nature. Furthermore, the adsorption process was spontaneous as indicated by negative values of the adsorption free energy. Treatment of real produced water using electrocoagulation resulted in 98% boron removal. The hydrothermal mineralization study showed that borate minerals (Inyoite, Takadaite and Nifontovite) can be recovered as recyclable precipitate from electrocoagulation flocs of produced water.

  9. Liposomal boron delivery for neutron capture therapy.

    PubMed

    Nakamura, Hiroyuki

    2009-01-01

    Tumor cell destruction in boron neutron capture therapy (BNCT) is due to the nuclear reaction between (10)B and thermal neutrons. The thermal neutrons have an energy of 0.025 eV, clearly below the threshold energy required to ionize tissue components. However, neutron capture by (10)B produces lithium ion and helium (alpha-particles), which are high linear energy transfer (LET) particles, and dissipate their kinetic energy before traveling one cell diameter (5-9 microm) in biological tissues, ensuring their potential for precise cell killing. BNCT has been applied clinically for the treatment of malignant brain tumors, malignant melanoma, head and neck cancer, and hepatoma using two boron compounds: sodium borocaptate (Na(2)(10)B(12)H(11)SH; Na(2)(10)BSH) and l-p-boronophenylalanine (l-(10)BPA). These low molecular weight compounds are cleared easily from the cancer cells and blood. Therefore, high accumulation and selective delivery of boron compounds into tumor tissues are most important to achieve effective BNCT and to avoid damage of adjacent healthy cells. Much attention has been focused on the liposomal drug delivery system (DDS) as an attractive, intelligent technology of targeting and controlled release of (10)B compounds. Two approaches have been investigated for incorporation of (10)B into liposomes: (1) encapsulation of (10)B compounds into liposomes and (2) incorporation of (10)B-conjugated lipids into the liposomal bilayer. Our laboratory has developed boron ion cluster lipids for application of the latter approach. In this chapter, our boron lipid liposome approaches as well as recent developments of the liposomal boron delivery system are summarized.

  10. Physiological profiles of elite off-road and road cyclists.

    PubMed

    Wilber, R L; Zawadzki, K M; Kearney, J T; Shannon, M P; Disalvo, D

    1997-08-01

    There are minimal scientific data describing international caliber off-road cyclists (mountain bikers), particularly as they compare physiologically with international caliber road cyclists. Elite female (N = 10) and male (N = 10) athletes representing the United States National Off-Road Bicycle Association (NORBA) Cross-Country Team were compared with elite female (N = 10) and male (N = 10) athletes representing the United States Cycling Federation (USCF) National Road Team. Submaximal and maximal exercise responses were evaluated during the "championship" phase of the training year when athletes were in peak condition. All physiological tests were conducted at 1860 m. Among the female athletes, physiological responses at lactate threshold (LT) and during maximal exercise (MAX) were similar between NORBA and USCF cyclists with two exceptions: 1) USCF cyclists demonstrated a significantly greater (P < 0.05) absolute (16%) and relative (10%) maximal aerobic power, and 2) MAX heart rate was significantly higher (P < 0.05) for the USCF athletes (6%). Among the male athletes, physiological responses at LT and MAX were similar between NORBA and USCF cyclists with two exceptions: 1) USCF cyclists produced significantly greater (P < 0.05) absolute (18%) and relative (16%) power at LT, and 2) USCF cyclists produced significantly greater (P < 0.05) absolute (12%) and relative (10%) power at MAX. These data suggest that, in general, elite off-road cyclists possess physiological profiles that are similar to elite road cyclists.

  11. Thermal conductivity behavior of boron carbides

    NASA Technical Reports Server (NTRS)

    Wood, C.; Zoltan, A.; Emin, D.; Gray, P. E.

    1983-01-01

    Knowledge of the thermal conductivity of boron carbides is necessary to evaluate its potential for high temperature thermoelectric energy conversion applications. The thermal diffusivity of hot pressed boron carbide B/sub 1-x/C/sub x/ samples as a function of composition, temperature and temperature cycling was measured. These data in concert with density and specific heat data yield the thermal conductivities of these materials. The results in terms of a structural model to explain the electrical transport data and novel mechanisms for thermal conduction are discussed.

  12. Boron Nitride Nanotubes-Reinforced Glass Composites

    NASA Technical Reports Server (NTRS)

    Bansal, Narottam; Hurst, Janet B.; Choi, Sung R.

    2005-01-01

    Boron nitride nanotubes of significant lengths were synthesized by reaction of boron with nitrogen. Barium calcium aluminosilicate glass composites reinforced with 4 weight percent of BN nanotubes were fabricated by hot pressing. Ambient-temperature flexure strength and fracture toughness of the glass-BN nanotube composites were determined. The strength and fracture toughness of the composite were higher by as much as 90 and 35 percent, respectively, than those of the unreinforced glass. Microscopic examination of the composite fracture surfaces showed pullout of the BN nanotubes. The preliminary results on the processing and improvement in mechanical properties of BN nanotube reinforced glass matrix composites are being reported here for the first time.

  13. Tight-Binding study of Boron structures

    NASA Astrophysics Data System (ADS)

    McGrady, Joseph W.; Papaconstantopoulos, Dimitrios A.; Mehl, Michael J.

    2014-10-01

    We have performed Linearized Augmented Plane Wave (LAPW) calculations for five crystal structures (alpha, dhcp, sc, fcc, bcc) of Boron which we then fitted to a non-orthogonal tight-binding model following the Naval Research Laboratory Tight-Binding (NRL-TB) method. The predictions of the NRL-TB approach for complicated Boron structures such as R105 (or β-rhombohedral) and T190 are in agreement with recent first-principles calculations. Fully utilizing the computational speed of the NRL-TB method we calculated the energy differences of various structures, including those containing vacancies using supercells with up to 5000 atoms.

  14. Proton linacs for boron neutron capture therapy

    SciTech Connect

    Lennox, A.J. |

    1993-08-01

    Recent advances in the ability to deliver boron-containing drugs to brain tumors have generated interest in {approximately}4 MeV linacs as sources of epithermal neutrons for radiation therapy. In addition, fast neutron therapy facilities have been studying methods to moderate their beams to take advantage of the high cross section for epithermal neutrons on boron-10. This paper describes the technical issues involved in each approach and presents the motivation for undertaking such studies using the Fermilab linac. the problems which must be solved before therapy can begin are outlined. Status of preparatory work and results of preliminary measurements are presented.

  15. Titanium reinforced boron-polyimide composite

    NASA Technical Reports Server (NTRS)

    Clark, G. A.; Clayton, K. I.

    1969-01-01

    Processing techniques for boron polyimide prepreg were developed whereby composites could be molded under vacuum bag pressure only. A post-cure cycle was developed which resulted in no loss in room temperature mechanical properties of the composite at any time during up to 16 hours at 650 F. A design utilizing laminated titanium foil was developed to achieve a smooth transition of load from the titanium attachment points into the boron-reinforced body of the structure. The box beam test article was subjected to combined bending and torsional loads while exposed to 650 F. Loads were applied incrementally until failure occurred at 83% design limit load.

  16. Boron nitride nanotubes for spintronics.

    PubMed

    Dhungana, Kamal B; Pati, Ranjit

    2014-09-22

    With the end of Moore's law in sight, researchers are in search of an alternative approach to manipulate information. Spintronics or spin-based electronics, which uses the spin state of electrons to store, process and communicate information, offers exciting opportunities to sustain the current growth in the information industry. For example, the discovery of the giant magneto resistance (GMR) effect, which provides the foundation behind modern high density data storage devices, is an important success story of spintronics; GMR-based sensors have wide applications, ranging from automotive industry to biology. In recent years, with the tremendous progress in nanotechnology, spintronics has crossed the boundary of conventional, all metallic, solid state multi-layered structures to reach a new frontier, where nanostructures provide a pathway for the spin-carriers. Different materials such as organic and inorganic nanostructures are explored for possible applications in spintronics. In this short review, we focus on the boron nitride nanotube (BNNT), which has recently been explored for possible applications in spintronics. Unlike many organic materials, BNNTs offer higher thermal stability and higher resistance to oxidation. It has been reported that the metal-free fluorinated BNNT exhibits long range ferromagnetic spin ordering, which is stable at a temperature much higher than room temperature. Due to their large band gap, BNNTs are also explored as a tunnel magneto resistance device. In addition, the F-BNNT has recently been predicted as an ideal spin-filter. The purpose of this review is to highlight these recent progresses so that a concerted effort by both experimentalists and theorists can be carried out in the future to realize the true potential of BNNT-based spintronics.

  17. Boron Nitride Nanotubes for Spintronics

    PubMed Central

    Dhungana, Kamal B.; Pati, Ranjit

    2014-01-01

    With the end of Moore's law in sight, researchers are in search of an alternative approach to manipulate information. Spintronics or spin-based electronics, which uses the spin state of electrons to store, process and communicate information, offers exciting opportunities to sustain the current growth in the information industry. For example, the discovery of the giant magneto resistance (GMR) effect, which provides the foundation behind modern high density data storage devices, is an important success story of spintronics; GMR-based sensors have wide applications, ranging from automotive industry to biology. In recent years, with the tremendous progress in nanotechnology, spintronics has crossed the boundary of conventional, all metallic, solid state multi-layered structures to reach a new frontier, where nanostructures provide a pathway for the spin-carriers. Different materials such as organic and inorganic nanostructures are explored for possible applications in spintronics. In this short review, we focus on the boron nitride nanotube (BNNT), which has recently been explored for possible applications in spintronics. Unlike many organic materials, BNNTs offer higher thermal stability and higher resistance to oxidation. It has been reported that the metal-free fluorinated BNNT exhibits long range ferromagnetic spin ordering, which is stable at a temperature much higher than room temperature. Due to their large band gap, BNNTs are also explored as a tunnel magneto resistance device. In addition, the F-BNNT has recently been predicted as an ideal spin-filter. The purpose of this review is to highlight these recent progresses so that a concerted effort by both experimentalists and theorists can be carried out in the future to realize the true potential of BNNT-based spintronics. PMID:25248070

  18. Ultrahard nanotwinned cubic boron nitride.

    PubMed

    Tian, Yongjun; Xu, Bo; Yu, Dongli; Ma, Yanming; Wang, Yanbin; Jiang, Yingbing; Hu, Wentao; Tang, Chengchun; Gao, Yufei; Luo, Kun; Zhao, Zhisheng; Wang, Li-Min; Wen, Bin; He, Julong; Liu, Zhongyuan

    2013-01-17

    Cubic boron nitride (cBN) is a well known superhard material that has a wide range of industrial applications. Nanostructuring of cBN is an effective way to improve its hardness by virtue of the Hall-Petch effect--the tendency for hardness to increase with decreasing grain size. Polycrystalline cBN materials are often synthesized by using the martensitic transformation of a graphite-like BN precursor, in which high pressures and temperatures lead to puckering of the BN layers. Such approaches have led to synthetic polycrystalline cBN having grain sizes as small as ∼14 nm (refs 1, 2, 4, 5). Here we report the formation of cBN with a nanostructure dominated by fine twin domains of average thickness ∼3.8 nm. This nanotwinned cBN was synthesized from specially prepared BN precursor nanoparticles possessing onion-like nested structures with intrinsically puckered BN layers and numerous stacking faults. The resulting nanotwinned cBN bulk samples are optically transparent with a striking combination of physical properties: an extremely high Vickers hardness (exceeding 100 GPa, the optimal hardness of synthetic diamond), a high oxidization temperature (∼1,294 °C) and a large fracture toughness (>12 MPa m(1/2), well beyond the toughness of commercial cemented tungsten carbide, ∼10 MPa m(1/2)). We show that hardening of cBN is continuous with decreasing twin thickness down to the smallest sizes investigated, contrasting with the expected reverse Hall-Petch effect below a critical grain size or the twin thickness of ∼10-15 nm found in metals and alloys.

  19. Dietary boron: progress in establishing essential roles in human physiology.

    PubMed

    Hunt, Curtiss D

    2012-06-01

    This review summarizes the progress made in establishing essential roles for boron in human physiology and assesses that progress in view of criteria for essentiality of elements. The evidence to date suggests that humans and at least some higher animals may use boron to support normal biological functions. These include roles in calcium metabolism, bone growth and maintenance, insulin metabolism, and completion of the life cycle. The biochemical mechanisms responsible for these effects are poorly understood but the nature of boron biochemistry suggests further characterization of the cell signaling molecules capable of complexing with boron. Such characterization may provide insights into the biochemical function(s) of boron in humans.

  20. Low pressure growth of cubic boron nitride films

    NASA Technical Reports Server (NTRS)

    Ong, Tiong P. (Inventor); Shing, Yuh-Han (Inventor)

    1997-01-01

    A method for forming thin films of cubic boron nitride on substrates at low pressures and temperatures. A substrate is first coated with polycrystalline diamond to provide a uniform surface upon which cubic boron nitride can be deposited by chemical vapor deposition. The cubic boron nitride film is useful as a substitute for diamond coatings for a variety of applications in which diamond is not suitable. any tetragonal or hexagonal boron nitride. The cubic boron nitride produced in accordance with the preceding example is particularly well-suited for use as a coating for ultra hard tool bits and abrasives, especially those intended to use in cutting or otherwise fabricating iron.

  1. Magnetron sputtered boron films and TI/B multilayer structures

    DOEpatents

    Makowiecki, Daniel M.; Jankowski, Alan F.

    1993-01-01

    A method is described for the production of thin boron and titanium/boron films by magnetron sputter deposition. The amorphous boron films contain no morphological growth features, unlike those found when thin films are prepared by various physical vapor deposition processes. Magnetron sputter deposition method requires the use of a high density crystalline boron sputter target which is prepared by hot isostatic pressing. Thin boron films prepared by this method are useful for ultra-thin band pass filters as well as the low Z element in low Z/high Z mirrors which enhance reflectivity from grazing to normal incidence.

  2. Magnetron sputtered boron films and TI/B multilayer structures

    DOEpatents

    Makowiecki, D.M.; Jankowski, A.F.

    1993-04-20

    A method is described for the production of thin boron and titanium/boron films by magnetron sputter deposition. The amorphous boron films contain no morphological growth features, unlike those found when thin films are prepared by various physical vapor deposition processes. Magnetron sputter deposition method requires the use of a high density crystalline boron sputter target which is prepared by hot isostatic pressing. Thin boron films prepared by this method are useful for ultra-thin band pass filters as well as the low Z element in low Z/high Z mirrors which enhance reflectivity from grazing to normal incidence.

  3. Magnetron sputtered boron films and Ti/B multilayer structures

    DOEpatents

    Makowiecki, D.M.; Jankowski, A.F.

    1995-02-14

    A method is described for the production of thin boron and titanium/boron films by magnetron sputter deposition. The amorphous boron films contain no morphological growth features, unlike those found when thin films are prepared by various physical vapor deposition processes. Magnetron sputter deposition method requires the use of a high density crystalline boron sputter target which is prepared by hot isostatic pressing. Thin boron films prepared by this method are useful for ultra-thin band pass filters as well as the low Z element in low Z/high Z mirrors which enhance reflectivity from grazing to normal incidence. 6 figs.

  4. Magnetron sputtered boron films and Ti/B multilayer structures

    DOEpatents

    Makowiecki, Daniel M.; Jankowski, Alan F.

    1995-01-01

    A method is described for the production of thin boron and titanium/boron films by magnetron sputter deposition. The amorphous boron films contain no morphological growth features, unlike those found when thin films are prepared by various physical vapor deposition processes. Magnetron sputter deposition method requires the use of a high density crystalline boron sputter target which is prepared by hot isostatic pressing. Thin boron films prepared by this method are useful for ultra-thin band pass filters as well as the low Z element in low Z/high Z mirrors which enhance reflectivity from grazing to normal incidence.

  5. The contribution of on-road studies of road user behaviour to improving road safety.

    PubMed

    Lenné, Michael G

    2013-09-01

    For over 40 years transport safety researchers have been using methods of vehicle instrumentation to gain greater insights into the factors that contribute to road user crash risk and the associated crash factors. In the previous decade in particular the widespread availability of lower cost and more advanced methods of vehicle instrumentation and recording technologies are supporting the increasing number of on-road research studies worldwide. The design of these studies ranges from multi-method studies using instrumented test vehicles and defined driving routes, to field operational tests, through to much larger and more naturalistic studies. It is timely to assess the utility of these methods for studying the influences of driver characteristics and states, the design and operation of the road system, and the influences of in-vehicle technologies on behaviour and safety for various road user groups. This special issue considers the extent to which on-road studies using vehicle instrumentation have been used to advance knowledge across these areas of road safety research. The papers included in this issue illustrate how research using instrumented test vehicles continues to generate new knowledge, and how the larger scale United States and European naturalistic and field operational test studies are providing a wealth of data about road user behaviour in real traffic. This is balanced with a number of studies that present methodological developments in data collection and analysis methods that, while promising, need further validation. The use of on-road methods to accurately describe the behaviours occurring in everyday real-world conditions, to quantify risks for safety critical events, and an improved understanding of the factors that contribute to risk, clearly has huge potential to promote further road trauma reductions.

  6. Road traffic injuries: a stocktaking.

    PubMed

    Mohan, Dinesh

    2008-08-01

    Once we accept that road traffic injury control is a public health problem, and that we have an ethical responsibility to arrange for the safety of individuals, then it follows that health and medical professionals have to assume responsibility for participating in efforts to control this pandemic. Over 1.2 million people die of road traffic crashes annually. Road traffic injuries are among the second to the sixth leading causes of death in the age groups 15-60 years in all countries around the world. Control of road traffic injuries is going to require very special efforts as patterns are different in high- and lower-income countries, and while some countermeasures are applicable internationally, others will need further research and innovation. We will need to focus on the safety of pedestrians, bicyclists and motorcyclists, speed control, and prevention of driving under the influence of alcohol.

  7. Road Rage: What's Driving It?

    PubMed

    Sansone, Randy A; Sansone, Lori A

    2010-07-01

    Up to one-third of community participants report being perpetrators of road rage, indicating that various forms of road rage are relatively commonplace. However, only two percent or less of incidents culminate in serious damage to persons or vehicles. The most common offenders appear to be young and male. A number of factors may contribute to road rage, including environmental factors (e.g., greater number of miles driven per day, traffic density), nonspecific psychological factors (e.g., displaced aggression, attribution of blame to others), and bona fide Axis I and II disorders. The most common Axis I disorders appear to be related to alcohol and substance misuse, whereas possible Axis II disorders include borderline and antisocial personality disorders. Being aware of these contributory factors to road rage may improve general clinical awareness of the nature and treatment of perpetrators.

  8. Perceived density of road maps.

    PubMed

    Schwartz-Chassidim, Hadas; Meyer, Joachim; Parmet, Yisrael; Rogatka, Efrat; Amzaleg, Ohad

    2014-11-01

    Maps should be designed so that users can comprehend and use the information. Display decisions, such as choosing the scale at which an area is shown, depend on properties of the displayed information such as the perceived density (PD) of the information. Taking a psychophysical approach we suggest that the PD of information in a road map is related to the scale and properties of the mapped area. 54 participants rated the PD of 60 maps from different regions. We provide a simple model that predicts the PD of electronic road map displays, using the logarithm of the number of roads, the logarithm of the number of junctions and the length of the shown roads. The PD model was cross-validated using a different set of 60 maps (n = 44). The model can be used for automatically adjusting display scales and for evaluating map designs, considering the required PD to perform a map-related task.

  9. The Dilemma of Mountain Roads

    EPA Science Inventory

    Mountain roads and trails are proliferating throughout developing Southeast Asia with severe but largely unrecognized long-term consequences related to effects of landslides and surface erosion on communities and downstream resources.

  10. Road Weather and Connected Vehicles

    NASA Astrophysics Data System (ADS)

    Pisano, P.; Boyce, B. C.

    2015-12-01

    On average, there are over 5.8 M vehicle crashes each year of which 23% are weather-related. Weather-related crashes are defined as those crashes that occur in adverse weather or on slick pavement. The vast majority of weather-related crashes happen on wet pavement (74%) and during rainfall (46%). Connected vehicle technologies hold the promise to transform road-weather management by providing improved road weather data in real time with greater temporal and geographic accuracy. This will dramatically expand the amount of data that can be used to assess, forecast, and address the impacts that weather has on roads, vehicles, and travelers. The use of vehicle-based measurements of the road and surrounding atmosphere with other, more traditional weather data sources, and create road and atmospheric hazard products for a variety of users. The broad availability of road weather data from mobile sources will vastly improve the ability to detect and forecast weather and road conditions, and will provide the capability to manage road-weather response on specific roadway links. The RWMP is currently demonstrating how weather, road conditions, and related vehicle data can be used for decision making through an innovative Integrated Mobile Observations project. FHWA is partnering with 3 DOTs (MN, MI, & NV) to pilot these applications. One is a mobile alerts application called the Motorists Advisories and Warnings (MAW) and a maintenance decision support application. These applications blend traditional weather information (e.g., radar, surface stations) with mobile vehicle data (e.g., temperature, brake status, wiper status) to determine current weather conditions. These weather conditions, and other road-travel-relevant information, are provided to users via web and phone applications. The MAW provides nowcasts and short-term forecasts out to 24 hours while the EMDSS application can provide forecasts up to 72 hours in advance. The three DOTs have placed readers and external

  11. Observations of Novae From ROAD

    NASA Astrophysics Data System (ADS)

    Hambsch, F.-J.

    2014-12-01

    The author discusses observations of galactic novae and some extragalactic supernovae from his remote observatory ROAD (Remote Observatory Atacama Desert) he commenced in August 2011 with Nova Lupi 2011 (PR Lup). The observed novae are mainly chosen according to AAVSO Alert Notices and AAVSO Special Notices as published on their website. Examples of dense observations of different novae are presented. The focus goes to the different behaviors of their light curves. It also demonstrates the capability of the remote observatory ROAD.

  12. Hollow boron nitride nanospheres as boron reservoir for prostate cancer treatment

    NASA Astrophysics Data System (ADS)

    Li, Xia; Wang, Xiupeng; Zhang, Jun; Hanagata, Nobutaka; Wang, Xuebin; Weng, Qunhong; Ito, Atsuo; Bando, Yoshio; Golberg, Dmitri

    2017-01-01

    High global incidence of prostate cancer has led to a focus on prevention and treatment strategies to reduce the impact of this disease in public health. Boron compounds are increasingly recognized as preventative and chemotherapeutic agents. However, systemic administration of soluble boron compounds is hampered by their short half-life and low effectiveness. Here we report on hollow boron nitride (BN) spheres with controlled crystallinity and boron release that decrease cell viability and increase prostate cancer cell apoptosis. In vivo experiments on subcutaneous tumour mouse models treated with BN spheres demonstrated significant suppression of tumour growth. An orthotopic tumour growth model was also utilized and further confirmed the in vivo anti-cancer efficacy of BN spheres. Moreover, the administration of hollow BN spheres with paclitaxel leads to synergetic effects in the suppression of tumour growth. The work demonstrates that hollow BN spheres may function as a new agent for prostate cancer treatment.

  13. Hollow boron nitride nanospheres as boron reservoir for prostate cancer treatment.

    PubMed

    Li, Xia; Wang, Xiupeng; Zhang, Jun; Hanagata, Nobutaka; Wang, Xuebin; Weng, Qunhong; Ito, Atsuo; Bando, Yoshio; Golberg, Dmitri

    2017-01-06

    High global incidence of prostate cancer has led to a focus on prevention and treatment strategies to reduce the impact of this disease in public health. Boron compounds are increasingly recognized as preventative and chemotherapeutic agents. However, systemic administration of soluble boron compounds is hampered by their short half-life and low effectiveness. Here we report on hollow boron nitride (BN) spheres with controlled crystallinity and boron release that decrease cell viability and increase prostate cancer cell apoptosis. In vivo experiments on subcutaneous tumour mouse models treated with BN spheres demonstrated significant suppression of tumour growth. An orthotopic tumour growth model was also utilized and further confirmed the in vivo anti-cancer efficacy of BN spheres. Moreover, the administration of hollow BN spheres with paclitaxel leads to synergetic effects in the suppression of tumour growth. The work demonstrates that hollow BN spheres may function as a new agent for prostate cancer treatment.

  14. Cell cycle dependence of boron uptake from two boron compounds used for clinical neutron capture therapy.

    PubMed

    Yoshida, F; Matsumura, A; Shibata, Y; Yamamoto, T; Nakauchi, H; Okumura, M; Nose, T

    2002-12-10

    In neutron capture therapy, it is important that the boron is selectively uptaken by tumor cells. In the present study, we used flow cytometry to sort the cells in the G0/G1 phase and those in the G2/M phase, and the boron concentration in each fraction was measured with inductively coupled plasma atomic emission spectroscopy. The results revealed that sodium borocaptate and boronophenylalanine (BPA), were associated with higher rates of boron uptake in the G2/M than in the G0/G1 phase. However, the difference was more prominent in the case of BPA. The G2/M:G0/G1 ratio decreased as a function of exposure time in BPA containing culture medium, thereby indicating the cell cycle dependency of BPA uptake. Such heterogeneity of boron uptake by tumor cells should be considered for microdosimetry.

  15. Hollow boron nitride nanospheres as boron reservoir for prostate cancer treatment

    PubMed Central

    Li, Xia; Wang, Xiupeng; Zhang, Jun; Hanagata, Nobutaka; Wang, Xuebin; Weng, Qunhong; Ito, Atsuo; Bando, Yoshio; Golberg, Dmitri

    2017-01-01

    High global incidence of prostate cancer has led to a focus on prevention and treatment strategies to reduce the impact of this disease in public health. Boron compounds are increasingly recognized as preventative and chemotherapeutic agents. However, systemic administration of soluble boron compounds is hampered by their short half-life and low effectiveness. Here we report on hollow boron nitride (BN) spheres with controlled crystallinity and boron release that decrease cell viability and increase prostate cancer cell apoptosis. In vivo experiments on subcutaneous tumour mouse models treated with BN spheres demonstrated significant suppression of tumour growth. An orthotopic tumour growth model was also utilized and further confirmed the in vivo anti-cancer efficacy of BN spheres. Moreover, the administration of hollow BN spheres with paclitaxel leads to synergetic effects in the suppression of tumour growth. The work demonstrates that hollow BN spheres may function as a new agent for prostate cancer treatment. PMID:28059072

  16. Process of Making Boron-Fiber Reinforced Composite Tape

    NASA Technical Reports Server (NTRS)

    Belvin, Harry L. (Inventor); Cano, Roberto J. (Inventor); Johnston, Norman J. (Inventor); Marchello, Joseph M. (Inventor)

    2002-01-01

    The invention is an apparatus and method for producing a hybrid boron reinforced polymer matrix composition from powder pre-impregnated fiber tow bundles and a linear array of boron fibers. The boron fibers are applied onto the powder pre-impregnated fiber tow bundles and then are processed within a processing component having an impregnation bar assembly. After passing through variable-dimension forming nip-rollers, the powder pre-impregnated fiber tow bundles with the boron fibers become a hybrid boron reinforced polymer matrix composite tape. A driving mechanism pulls the powder pre-impregnated fiber tow bundles with boron fibers through the processing line of the apparatus and a take-up spool collects the formed hybrid boron-fiber reinforced polymer matrix composite tape.

  17. Mechanisms implicated in the effects of boron on wound healing.

    PubMed

    Nzietchueng, Rosine Mayap; Dousset, Brigitte; Franck, Patricia; Benderdour, Mohamed; Nabet, Pierre; Hess, Ketsia

    2002-01-01

    Recently, we demonstrated that boron modulates the turnover of the extracellular matrix and increases TNFalpha release. In the present study, we used an in vitro test to investigate the direct effect of boron on specific enzymes (elastase, trypsin-like enzymes, collagenase and alkaline phosphatase) implicated in extracellular matrix turnover. Boron decreased the elastase and alkaline phosphatase activity, but had no effect on trypsin and collagenase activities. The effect of boron on the enzyme activities was also tested in fibroblasts considered as an in vivo test. In contrast to the results obtained in vitro, boron enhanced the trypsin-like, collagenase, and cathepsin D activities in fibroblasts. Boron did not modify the generation of free radicals compared to the control and did not seem to act on the intracellular alkaline phosphatase activity, However, as it did enhance phosphorylation, it can be hypothesized that boron may affect living cells via a mediator, which could be TNFalpha whose transduction signal involves a cascade of phosphorylations.

  18. Annealing behaviour of boron atoms implanted into polyethyleneterephtalate

    NASA Astrophysics Data System (ADS)

    Vacík, J.; Hnatowicz, V.; Červená, J.; Peřina, V.; Popok, V.; Odzhaev, V.; Švorčík, V.; Rybka, V.; Arenholz, E.; Fink, D.

    2000-05-01

    Hundred keV B+ ions were implanted at high fluences into polyethyleneterephtalate (PET, Mylar) and the boron depth distributions were measured by the neutron depth profiling technique (NDP). Subsequently the implanted samples were annealed isochronally to determine the diffusional, trapping and detrapping behaviour of the boron atoms. The boron depth profiles of as-implanted samples differ significantly from those predicted by TRIM code. Pronounced inward and outward profile tails point at increased mobility and redistribution of boron atoms during the implantation. Thermal annealing to the temperatures below 100°C does not change the total boron content in the 1 μm thick surface layer and the boron depth profiles as well. For higher annealing temperatures a significant redistribution of boron atoms is observed.

  19. Boron uptake measurements in a rat model for Boron Neutron Capture Therapy of lung tumours.

    PubMed

    Bortolussi, S; Bakeine, J G; Ballarini, F; Bruschi, P; Gadan, M A; Protti, N; Stella, S; Clerici, A; Ferrari, C; Cansolino, L; Zonta, C; Zonta, A; Nano, R; Altieri, S

    2011-02-01

    Lung carcinoma is the leading cause of cancer mortality in the Western countries. Despite the introduction over the last few years of new therapeutic agents, survival from lung cancer has shown no discernible improvement in the last 20 years. For these reasons any efforts to find and validate new effective therapeutic procedures for lung cancer are very timely. The selective boron uptake in the tumour with respect to healthy tissues makes Boron Neutron Capture Therapy a potentially advantageous option in the treatment of tumours that affect whole vital organs, and that are surgically inoperable. To study the possibility of applying BNCT to the treatment of diffuse pulmonary tumours, an animal model for boron uptake measurements in lung metastases was developed. Both healthy and tumour-bearing rats were infused with Boronophenylalanine (BPA) and sacrificed at different time intervals after drug administration. The lungs were extracted, and prepared for boron analysis by neutron autoradiography and α-spectroscopy. The boron concentrations in tumour and normal lung were plotted as a function of the time elapsed after BPA administration. The concentration in tumour is almost constant within the error bars for all the time intervals of the experiment (1-8 h), while the curve in normal lung decreases after 4 h from BPA infusion. At 4 h, the ratio of boron concentration in tumour to boron concentration in healthy lung is higher than 3, and it stays above this level up to 8 h. Also the images of boron distribution in the samples, obtained by neutron autoradiography, show a selective absorption in the metastases.

  20. The geochemical cycle of boron: Constraints from boron isotope partitioning experiments between mica and fluid

    NASA Astrophysics Data System (ADS)

    Wunder, Bernd; Meixner, Anette; Romer, Rolf L.; Wirth, Richard; Heinrich, Wilhelm

    2005-10-01

    The fractionation of boron isotopes between synthetic boromuscovite and fluid was experimentally determined at 3.0 GPa/500 °C and 3.0 GPa/700 °C. For near-neutral fluids Δ 11B (mica-fluid) = δ 11B (mica) - δ 11B (fluid) is - 10.9 ± 1.3‰ at 500 °C, and - 6.5 ± 0.4‰ at 700 °C. This supports earlier assumptions that the main fractionation effect is due to the change from trigonal coordination of boron in neutral fluids to tetrahedrally coordinated boron in micas, clays and melts. The T-dependence of this effect is approximated by the equation Δ 11B (mica,clay,melt-neutral fluid) = - 10.69 · (1000/ T [K]) + 3.88; R2 = 0.992, valid from 25 °C for fluid-clay up to about 1000 °C for fluid-silicate melt. Experiments at 0.4 GPa that used strongly basic fluids produced significantly lower fractionations with Δ 11B (mica-fluid) of - 7.4 ± 1.0‰ at 400 °C, and - 4.8 ± 1.0‰ at 500 °C, showing the reduced fractionation effect when large amounts of boron in basic fluids are tetrahedrally coordinated. Field studies have shown that boron concentrations and 11B/ 10B-ratios in volcanic arcs systematically decrease across the arc with increasing distance from the trench, thus reflecting the thermal structure of the subducting slab. Our experiments show that the boron isotopic signature in volcanic arcs probably results from continuous dehydration of micas along a distinct P- T range. Continuous slab dehydration and boron transport via fluid into the mantle wedge is responsible for the boron isotopic signature in volcanic arcs.

  1. A prospective, randomized, double-blind study of the anesthetic efficacy of sodium bicarbonate buffered 2% lidocaine with 1:100,000 epinephrine in inferior alveolar nerve blocks.

    PubMed

    Whitcomb, Michael; Drum, Melissa; Reader, Al; Nusstein, John; Beck, Mike

    2010-01-01

    The authors, using a crossover design, randomly administered, in a double-blind manner, inferior alveolar nerve (IAN) blocks using a buffered 2% lidocaine with 1:100,000 epinephrine/sodium bicarbonate formulation and an unbuffered 2% lidocaine with 1:100,000 epinephrine formulation at 2 separate appointments spaced at least 1 week apart. An electric pulp tester was used in 4-minute cycles for 60 minutes to test for anesthesia of the first and second molars, premolars, and lateral and central incisors. Anesthesia was considered successful when 2 consecutive 80 readings were obtained within 15 minutes, and the 80 reading was continuously sustained for 60 minutes. For the buffered 2% lidocaine with 1:100,000 epinephrine/sodium bicarbonate formulation, successful pulpal anesthesia ranged from 10-71%. For the unbuffered 2% lidocaine with 1:100,000 epinephrine formulation, successful pulpal anesthesia ranged from 10-72%. No significant differences between the 2 anesthetic formulations were noted. The buffered lidocaine formulation did not statistically result in faster onset of pulpal anesthesia or less pain during injection than did the unbuffered lidocaine formulation. We concluded that buffering a 2% lidocaine with 1:100,000 epinephrine with sodium bicarbonate, as was formulated in the current study, did not statistically increase anesthetic success, provide faster onset, or result in less pain of injection when compared with unbuffered 2% lidocaine with 1:100,000 epinephrine for an IAN block.

  2. The investigation of physical conditions of boron uptake region in proton boron fusion therapy (PBFT)

    NASA Astrophysics Data System (ADS)

    Jung, Joo-Young; Yoon, Do-Kun; Lee, Heui Chang; Lu, Bo; Suh, Tae Suk

    2016-09-01

    We conducted a quantitative study to identify the effectiveness of proton boron fusion therapy (PBFT). Four simulation scenarios were designed to investigate the escalation in total dose with the proton boron reaction using a Monte Carlo n-particle extended (MCNPX 2.6.0) simulation. The peak integrated dose was obtained for three different physical conditions (i.e., boron uptake region (BUR) thickness, BUR location, and boron concentration) with differing proton beam energy (60-90 MeV). We found that the peak integrated dose was increased by up to 96.62% compared to the pristine proton Bragg-peak. For the synergetic effect to take place with 60-70 MeV proton beam, the BUR had to be at least 0.3 cm thick while spanning the Bragg-peak. Similarly to the thickness, the BUR location needed to be within 0.3 cm from the Bragg-peak when the thickness was maintained at 0.9 cm. An effective proton boron reaction required the boron concentration to be equal to or greater than 14.4 mg/g. These results demonstrate the impact of various physical and beam conditions of the PBFT, which are critical environmental factors for the treatment planning. We envision that this study will advance our understanding of the PBFT, which can be an invaluable treatment method for maximizing the potential of proton therapy.

  3. In vitro and in vivo studies of boron neutron capture therapy: boron uptake/washout and cell death.

    PubMed

    Ferrari, C; Bakeine, J; Ballarini, F; Boninella, A; Bortolussi, S; Bruschi, P; Cansolino, L; Clerici, A M; Coppola, A; Di Liberto, R; Dionigi, P; Protti, N; Stella, S; Zonta, A; Zonta, C; Altieri, S

    2011-04-01

    Boron neutron capture therapy (BNCT) is a binary radiotherapy based on thermal-neutron irradiation of cells enriched with (10)B, which produces α particles and (7)Li ions of short range and high biological effectiveness. The selective uptake of boron by tumor cells is a crucial issue for BNCT, and studies of boron uptake and washout associated with cell survival studies can be of great help in developing clinical applications. In this work, boron uptake and washout were characterized both in vitro for the DHDK12TRb (DHD) rat colon carcinoma cell line and in vivo using rats bearing liver metastases from DHD cells. Despite a remarkable uptake, a large boron release was observed after removal of the boron-enriched medium from in vitro cell cultures. However, analysis of boron washout after rat liver perfusion in vivo did not show a significant boron release, suggesting that organ perfusion does not limit the therapeutic effectiveness of the treatment. The survival of boron-loaded cells exposed to thermal neutrons was also assessed; the results indicated that the removal of extracellular boron does not limit treatment effectiveness if adequate amounts of boron are delivered and if the cells are kept at low temperature. Cell survival was also investigated theoretically using a mechanistic model/Monte Carlo code originally developed for radiation-induced chromosome aberrations and extended here to cell death; good agreement between simulation outcomes and experimental data was obtained.

  4. NEW ADVANCES IN BORON SOIL CHEMISTRY

    EPA Science Inventory

    Boron is an essential plant micronutrient for which the range between deficiency and toxicity is narrower than for any other nutrient element. Plants respond directly to the amount of B in soil solution and only indirectly to the amount of B adsorbed on soil particle surfaces. ...

  5. Investigating the Boron Requirement of Plants.

    ERIC Educational Resources Information Center

    Bohnsack, Charles W.

    1991-01-01

    This article describes a simple and rapid method for using summer squash to investigate born deficiency in plants. Author asserts that students are likely to feel challenged by laboratory exercises and projects that focus on the role boron plays in plant growth because it is an unresolved problem in biology. (PR)

  6. Advances in boronization on NSTX-Upgrade

    NASA Astrophysics Data System (ADS)

    Skinner, C. H.; Blanchard, W.; Cai, D.; Jaworski, M.; Bedoya, F.; Allain, J. P.; Scotti, F.; Koel, B. E.

    2016-10-01

    Boronization has been effective in reducing plasma impurities and enabling access to higher density, higher confinement plasmas in many magnetic fusion devices. The National Spherical Torus eXperiment, NSTX, has recently undergone a major upgrade to NSTX-U in order to develop the physics basis for a ST-based Fusion Nuclear Science Facility (FNSF) with capability for double the toroidal field, plasma current, and NBI heating power and increased pulse duration from 1 - 1.5 s to 5 - 8 s. A new deuterated tri-methyl boron conditioning system was implemented together with a novel surface analysis diagnostic (MAPP). We report on the spatial distribution of the boron deposition versus discharge pressure, gas injection and electrode location. The oxygen concentration of the plasma facing surface was measured by in-vacuo XPS and increased both with plasma exposure and with exposure to trace residual gases. This increase was correlated with the rise of oxygen emission from the plasma. A dedicated experiment is planned to optimize the boronization process including XPS measurements of the plasma facing surface under specific plasma conditions. We will report on the results. Support was provided through DOE Contract Number DE-AC02-09CH11466.

  7. New insight into pecan boron nutrition

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alternate bearing by individual pecan [Carya illinoinensis (Wangenh.) K. Koch] trees is problematic for nut producers and processors. There are many unknowns regarding alternate bearing physiology, such as the relationship between boron and fruit set, nutmeat quality, and kernel maladies. Evidence...

  8. Intrinsic ferromagnetism in hexagonal boron nitride nanosheets

    SciTech Connect

    Si, M. S.; Gao, Daqiang E-mail: xueds@lzu.edu.cn; Yang, Dezheng; Peng, Yong; Zhang, Z. Y.; Xue, Desheng E-mail: xueds@lzu.edu.cn; Liu, Yushen; Deng, Xiaohui; Zhang, G. P.

    2014-05-28

    Understanding the mechanism of ferromagnetism in hexagonal boron nitride nanosheets, which possess only s and p electrons in comparison with normal ferromagnets based on localized d or f electrons, is a current challenge. In this work, we report an experimental finding that the ferromagnetic coupling is an intrinsic property of hexagonal boron nitride nanosheets, which has never been reported before. Moreover, we further confirm it from ab initio calculations. We show that the measured ferromagnetism should be attributed to the localized π states at edges, where the electron-electron interaction plays the role in this ferromagnetic ordering. More importantly, we demonstrate such edge-induced ferromagnetism causes a high Curie temperature well above room temperature. Our systematical work, including experimental measurements and theoretical confirmation, proves that such unusual room temperature ferromagnetism in hexagonal boron nitride nanosheets is edge-dependent, similar to widely reported graphene-based materials. It is believed that this work will open new perspectives for hexagonal boron nitride spintronic devices.

  9. Intrinsic ferromagnetism in hexagonal boron nitride nanosheets.

    PubMed

    Si, M S; Gao, Daqiang; Yang, Dezheng; Peng, Yong; Zhang, Z Y; Xue, Desheng; Liu, Yushen; Deng, Xiaohui; Zhang, G P

    2014-05-28

    Understanding the mechanism of ferromagnetism in hexagonal boron nitride nanosheets, which possess only s and p electrons in comparison with normal ferromagnets based on localized d or f electrons, is a current challenge. In this work, we report an experimental finding that the ferromagnetic coupling is an intrinsic property of hexagonal boron nitride nanosheets, which has never been reported before. Moreover, we further confirm it from ab initio calculations. We show that the measured ferromagnetism should be attributed to the localized π states at edges, where the electron-electron interaction plays the role in this ferromagnetic ordering. More importantly, we demonstrate such edge-induced ferromagnetism causes a high Curie temperature well above room temperature. Our systematical work, including experimental measurements and theoretical confirmation, proves that such unusual room temperature ferromagnetism in hexagonal boron nitride nanosheets is edge-dependent, similar to widely reported graphene-based materials. It is believed that this work will open new perspectives for hexagonal boron nitride spintronic devices.

  10. Intrinsic ferromagnetism in hexagonal boron nitride nanosheets

    NASA Astrophysics Data System (ADS)

    Si, M. S.; Gao, Daqiang; Yang, Dezheng; Peng, Yong; Zhang, Z. Y.; Xue, Desheng; Liu, Yushen; Deng, Xiaohui; Zhang, G. P.

    2014-05-01

    Understanding the mechanism of ferromagnetism in hexagonal boron nitride nanosheets, which possess only s and p electrons in comparison with normal ferromagnets based on localized d or f electrons, is a current challenge. In this work, we report an experimental finding that the ferromagnetic coupling is an intrinsic property of hexagonal boron nitride nanosheets, which has never been reported before. Moreover, we further confirm it from ab initio calculations. We show that the measured ferromagnetism should be attributed to the localized π states at edges, where the electron-electron interaction plays the role in this ferromagnetic ordering. More importantly, we demonstrate such edge-induced ferromagnetism causes a high Curie temperature well above room temperature. Our systematical work, including experimental measurements and theoretical confirmation, proves that such unusual room temperature ferromagnetism in hexagonal boron nitride nanosheets is edge-dependent, similar to widely reported graphene-based materials. It is believed that this work will open new perspectives for hexagonal boron nitride spintronic devices.

  11. Tetrahedral boron in naturally occurring tourmaline

    SciTech Connect

    Tagg, S.L.; Cho, H.; Dyar, M.D.; Grew, E.S.

    1999-09-01

    Evidence for boron in both trigonal and tetrahedral coordination has been found in {sup 11}B magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) spectra of natural, inclusion-free specimens of aluminum-rich lithian tourmaline from granitic pregmatites.

  12. Fuel-Solid Propellant Boron Combustion.

    DTIC Science & Technology

    1986-08-15

    liner A11 ArA C- 00 ujI 120 is supported by a Nextel braided composite fiber wrapping, which is in turn surrounded by Fiberfrax insulating block. This...assembly is composed of tungsten/rhenium walls, supported by an assembly of Nextel, Fiberfrax , silicon phenolic and boron nitride insulators, encased in

  13. Axial residual stresses in boron fibers

    NASA Technical Reports Server (NTRS)

    Behrendt, D. R.

    1978-01-01

    The axial residual stress distribution as a function of radius was determined from the fiber surface to the core including the average residual stress in the core. Such measurements on boron on tungsten (B/W) fibers show that the residual stresses for 102, 142, 203, and 366 micron diameter fibers were similar, being compressive at the surface and changing monotonically to a region of tensile within the boron. At approximately 25 percent of the original radius, the stress reaches a maximum tensile stress of about 860 mn/sq.m and then decreases to a compressive stress near the tungsten boride core. Data were presented for 203 micron diameter B/W fibers that show annealing above 900 C reduces the residual stresses. A comparison between 102 micron diameter B/W and boron on carbon (b/C) shows that the residual stresses were similar in the outer regions of the fibers, but that large differences near and in the core were observed. The effects of these residual stresses on the fracture of boron fibers were discussed.

  14. Powdered Hexagonal Boron Nitride Reducing Nanoscale Wear

    NASA Astrophysics Data System (ADS)

    Chkhartishvili, L.; Matcharashvili, T.; Esiava, R.; Tsagareishvili, O.; Gabunia, D.; Margiev, B.; Gachechiladze, A.

    2013-05-01

    A morphology model is suggested for nano-powdered hexagonal boron nitride that can serve as an effective solid additive to liquid lubricants. It allows to estimate the specific surface, that is a hard-to-measure parameter, based on average size of powder particles. The model can be used also to control nanoscale wear processes.

  15. Energetics of Boron Doping of Carbon Pores

    NASA Astrophysics Data System (ADS)

    Wexler, Carlos; St. John, Alexander; Connolly, Matthew

    2014-03-01

    Carbon-based materials show promise, given their light weight, large surface areas and low cost for storage of hydrogen and other gases, e.g., for energy applications. Alas, the interaction of H2 and carbon, 4-5kJ/mol, is insufficient for room-temperature operation. Boron doping of carbon materials could raise the binding energy of H2 to 12-15kJ/mol. The nature of the incorporation of boron into a carbon structure has not been studied so far. In this talk we will address the energetics of boron incorporation into a carbon matrix via adsorption and decomposition of decaborane by first principles calculations. These demonstrate: (a) A strong adsorption of decaborane to carbon (70-80kJ/mol) resulting in easy incorporation of decaborane, sufficient for up to 10-20% B:C at low decaborane vapour pressures. (b) Identification that boron acts as an electron acceptor when incorporated substitutionally into a graphene-like material, as expected due to its valence. (c) The electrostatic field near the molecule is responsible for ca. 2/3 of the enhancement of the H2-adsorbent interaction in aromatic compounds such as pyrene, coronene and ovalene. Supported by DOE DE-FG36-08GO18142, ACS-PRF 52696-ND5, and NSF 1069091.

  16. Boron Nitride Nanotubes for Engineering Applications

    NASA Technical Reports Server (NTRS)

    Hurst, Janet; Hull, David; Gorican, Daniel

    2005-01-01

    Boron nitride nanotubes (BNNT) are of significant interest to the scientific and technical communities for many of the same reasons that carbon nanotubes (CNT) have attracted wide attention. Both materials have potentially unique and important properties for structural and electronic applications. However of even more consequence than their similarities may be the complementary differences between carbon and boron nitride nanotubes While BNNT possess a very high modulus similar to CNT, they also possess superior chemical and thermal stability. Additionally, BNNT have more uniform electronic properties, with a uniform band gap of 5.5 eV while CNT vary from semi-conductive to highly conductive behavior. Boron nitride nanotubes have been synthesized both in the literature and at NASA Glenn Research Center, by a variety of methods such as chemical vapor deposition, arc discharge and reactive milling. Consistent large scale production of a reliable product has proven difficult. Progress in the reproducible synthesis of 1-2 gram sized batches of boron nitride nanotubes will be discussed as well as potential uses for this unique material.

  17. Boron nitride solid state neutron detector

    DOEpatents

    Doty, F. Patrick

    2004-04-27

    The present invention describes an apparatus useful for detecting neutrons, and particularly for detecting thermal neutrons, while remaining insensitive to gamma radiation. Neutrons are detected by direct measurement of current pulses produced by an interaction of the neutrons with hexagonal pyrolytic boron nitride.

  18. NEW ADVANCES IN BORON SOIL CHEMISTRY - Paper

    EPA Science Inventory

    Boron is an essential plant micronutrient for which the range between deficiency and toxicity is narrower than for any other nutrient element. Plants respond directly to the amount of B in soil solution and only indirectly to the amount of B adsorbed on soil particle surfaces. ...

  19. Biological activity of N(4)-boronated derivatives of 2'-deoxycytidine, potential agents for boron-neutron capture therapy.

    PubMed

    Nizioł, Joanna; Uram, Łukasz; Szuster, Magdalena; Sekuła, Justyna; Ruman, Tomasz

    2015-10-01

    Boron-neutron capture therapy (BNCT) is a binary anticancer therapy that requires boron compound for nuclear reaction during which high energy alpha particles and lithium nuclei are formed. Unnatural, boron-containing nucleoside with hydrophobic pinacol moiety was investigated as a potential BNCT boron delivery agent. Biological properties of this compound are presented for the first time and prove that boron nucleoside has low cytotoxicity and that observed apoptotic effects suggest alteration of important functions of cancer cells. Mass spectrometry analysis of DNA from cancer cells proved that boron nucleoside is inserted into nucleic acids as a functional nucleotide derivative. NMR studies present very high degree of similarity of natural dG-dC base pair with dG-boron nucleoside system.

  20. Prediction of Boron-Boron Triple-Bond Polymers Stabilized by Janus-Type Bis(N-heterocyclic) Carbenes.

    PubMed

    Fantuzzi, Felipe; Chaer Nascimento, Marco A

    2015-05-18

    A class of polymeric compounds containing boron-boron triple bonds stabilized by N-heterocyclic biscarbenes is proposed. Since a triply bonded B2 is related to its third excited state, the predicted macromolecule would be composed by several units of an electronically excited first-row homonuclear dimer. Moreover, it is shown that the replacement of biscarbene with N2 or CO as spacers could change the bonding profile of the boron-boron units to a cumulene-like structure. Based on these results, different types of diboryne polymers are proposed, which could lead to an unprecedented set of boron materials with distinct physical properties. The novel diboryne macromolecules could be synthesized by the reaction of Janus-type biscarbenes with tetrabromodiborane, B2 Br4 , and sodium naphthalenide, [Na(C10 H8 )], similarly to Braunschweig's work on the room temperature stable boron-boron triple bond compounds (Science, 2012, 336, 1420).

  1. Boron carbide nanowires: Synthesis and characterization

    NASA Astrophysics Data System (ADS)

    Guan, Zhe

    Bulk boron carbide has been widely used in ballistic armored vest and the property characterization has been heavily focused on mechanical properties. Even though boron carbides have also been projected as a promising class of high temperature thermoelectric materials for energy harvesting, the research has been limited in this field. Since the thermal conductivity of bulk boron carbide is still relatively high, there is a great opportunity to take advantage of the nano effect to further reduce it for better thermoelectric performance. This dissertation work aims to explore whether improved thermoelectric performance can be found in boron carbide nanowires compared with their bulk counterparts. This dissertation work consists of four main parts. (1) Synthesis of boron carbide nanowires. Boron carbide nanowires were synthesized by co-pyrolysis of diborane and methane at low temperatures (with 879 °C as the lowest) in a home-built low pressure chemical vapor deposition (LPCVD) system. The CVD-based method is energy efficient and cost effective. The as-synthesized nanowires were characterized by electron microscopy extensively. The transmission electron microscopy (TEM) results show the nanowires are single crystalline with planar defects. Depending on the geometrical relationship between the preferred growth direction of the nanowire and the orientation of the defects, the as-synthesized nanowires could be further divided into two categories: transverse fault (TF) nanowires grow normal to the defect plane, while axial fault (AF) ones grow within the defect plane. (2) Understanding the growth mechanism of as-synthesized boron carbide nanowires. The growth mechanism can be generally considered as the famous vapor-liquid-solid (VLS) mechanism. TF and AF nanowires were found to be guided by Ni-B catalysts of two phases. A TF nanowire is lead by a hexagonal phase catalyst, which was proved to be in a liquid state during reaction. While an AF nanowires is catalyzed by a

  2. Road safety and road traffic accidents in Saudi Arabia

    PubMed Central

    Mansuri, Farah A.; Al-Zalabani, Abdulmohsen H.; Zalat, Marwa M.; Qabshawi, Reem I.

    2015-01-01

    Objectives: To identify the changing trends and crucial preventive approaches to road traffic accidents (RTAs) adopted in the Kingdom of Saudi Arabia (KSA) over the last 2.5 decades, and to analyze aspects previously overlooked. Methods: This systematic review was based on evidence of RTAs in KSA. All articles published during the last 25 years on road traffic accident in KSA were analyzed. This study was carried out from December 2013 to May 2014 in the Department of Family and Community Medicine, Taibah University, Al-Madinah Al-Munawwarah, KSA. Results: Road traffic accidents accounted for 83.4% of all trauma admissions in 1984-1989, and no such overall trend was studied thereafter. The most frequently injured body regions as reported in the latest studies were head and neck, followed by upper and lower extremities, which was found to be opposite to that of the studies reported earlier. Hospital data showed an 8% non-significant increase in road accident mortalities in contrast to police records of a 27% significant reduction during the years 2005-2010. Excessive speeding was the most common cause reported in all recent and past studies. Conclusion: Disparity was common in the type of reporting of RTAs, outcome measures, and possible causes over a period of 2.5 decade. All research exclusively looked into the drivers’ faults. A sentinel surveillance of road crashes should be kept in place in the secondary and tertiary care hospitals for all regions of KSA. PMID:25828277

  3. Boron: elementary challenge for experimenters and theoreticians.

    PubMed

    Albert, Barbara; Hillebrecht, Harald

    2009-01-01

    Many of the fundamental questions regarding the solid-state chemistry of boron are still unsolved, more than 200 years after its discovery. Recently, theoretical work on the existence and stability of known and new modifications of the element combined with high-pressure and high-temperature experiments have revealed new aspects. A lot has also happened over the last few years in the field of reactions between boron and main group elements. Binary compounds such as B(6)O, MgB(2), LiB(1-x), Na(3)B(20), and CaB(6) have caused much excitement, but the electron-precise, colorless boride carbides Li(2)B(12)C(2), LiB(13)C(2), and MgB(12)C(2) as well as the graphite analogue BeB(2)C(2) also deserve special attention. Physical properties such as hardness, superconductivity, neutron scattering length, and thermoelectricity have also made boron-rich compounds attractive to materials research and for applications. The greatest challenges to boron chemistry, however, are still the synthesis of monophasic products in macroscopic quantities and in the form of single crystals, the unequivocal identification and determination of crystal structures, and a thorough understanding of their electronic situation. Linked polyhedra are the dominating structural elements of the boron-rich compounds of the main group elements. In many cases, their structures can be derived from those that have been assigned to modifications of the element. Again, even these require a critical revision and discussion.

  4. Extracting Road Vector Data from Raster Maps

    NASA Astrophysics Data System (ADS)

    Chiang, Yao-Yi; Knoblock, Craig A.

    Raster maps are an important source of road information. Because of the overlapping map features (e.g., roads and text labels) and the varying image quality, extracting road vector data from raster maps usually requires significant user input to achieve accurate results. In this paper, we present an accurate road vectorization technique that minimizes user input by combining our previous work on extracting road pixels and road-intersection templates to extract accurate road vector data from raster maps. Our approach enables GIS applications to exploit the road information in raster maps for the areas where the road vector data are otherwise not easily accessible, such as the countries of the Middle East. We show that our approach requires minimal user input and achieves an average of 93.2% completeness and 95.6% correctness in an experiment using raster maps from various sources.

  5. Encapsulating Urban Traffic Rhythms into Road Networks

    PubMed Central

    Wang, Junjie; Wei, Dong; He, Kun; Gong, Hang; Wang, Pu

    2014-01-01

    Using road GIS (geographical information systems) data and travel demand data for two U.S. urban areas, the dynamical driver sources of each road segment were located. A method to target road clusters closely related to urban traffic congestion was then developed to improve road network efficiency. The targeted road clusters show different spatial distributions at different times of a day, indicating that our method can encapsulate dynamical travel demand information into the road networks. As a proof of concept, when we lowered the speed limit or increased the capacity of road segments in the targeted road clusters, we found that both the number of congested roads and extra travel time were effectively reduced. In addition, the proposed modeling framework provided new insights on the optimization of transport efficiency in any infrastructure network with a specific supply and demand distribution. PMID:24553203

  6. Road Nail: Experimental Solar Powered Intelligent Road Marking System

    NASA Astrophysics Data System (ADS)

    Samardžija, Dragan; Teslić, Nikola; Todorović, Branislav M.; Kovač, Erne; Isailović, Đorđe; Miladinović, Bojan

    2012-03-01

    Driving in low visibility conditions (night time, fog or heavy precipitation) is particularly challenging task with an increased probability of traffic accidents and possible injuries. Road Nail is a solar powered intelligent road marking system of wirelessly networked signaling devices that improve driver safety in low visibility conditions along hazardous roadways. Nails or signaling devices are autonomous nodes with capability to accumulate energy, exchange wireless messages, detect approaching vehicles and emit signalization light. We have built an experimental test-bed that consists of 20 nodes and a cellular gateway. Implementation details of the above system, including extensive measurements and performance evaluations in realistic field deployments are presented. A novel distributed network topology discovery scheme is proposed which integrates both sensor and wireless communication aspects, where nodes act autonomously. Finally, integration of the Road Nail system with the cellular network and the Internet is described.

  7. Investigations on boron levels in drinking water sources in China.

    PubMed

    Xu, Ren-ji; Xing, Xiao-ru; Zhou, Qun-fang; Jiang, Gui-bin; Wei, Fu-sheng

    2010-06-01

    To evaluate boron contamination of public drinking water in China, both dissolved and total boron contents in 98 public drinking water sources from 49 cities, 42 brands of bottled water samples from supermarkets in several cities, and 58 water samples from boron industrial area were measured by inductively coupled plasma-mass spectrometry (ICP-MS). Our experimental results showed that boron existed in public drinking water sources mainly in dissolved status with total concentrations ranging from 0.003 to 0.337 mg/L (mean = 0.046 mg/L). The mean boron concentrations in mineral and pure bottled water were 0.052 and 0.028 mg/L, respectively. The results obtained in this work showed that there was no health risk on view of boron in public drinking water sources and bottled water. In boron industrial area, boron concentrations in surface water and ground water were 1.28 mg/L (range = 0.007-3.8 mg/L) and 18.3 mg/L (range = 0.015-140 mg/L), respectively, which indicated that boron industry caused boron pollution in local water system.

  8. Microstructural characterization of superalloy 718 with boron and phosphorus additions

    SciTech Connect

    Horton, J.A.; McKamey, C.G.; Miller, M.K.; Cao, W.D.; Kennedy, R.L.

    1997-06-01

    Boron and phosphorus additions are known to improve the stress rupture properties of IN-718. One possible mechanism to explain this property improvement relies on the boron and phosphorus additions slowing down the growth of {gamma}{double_prime} and {gamma}{prime} precipitates during high temperature service or aging. However, atom probe analysis found no segregation of boron and phosphorus to {gamma}-{gamma}{double_prime} or to {gamma}-{gamma}{prime} interfaces in the alloys with the high boron and high phosphorus levels. No difference in growth rates were found by transmission electron microscopy in the sizes of the {gamma}{double_prime} or {gamma}{prime} in alloys with high phosphorus and high boron as compared to commercial alloys and to alloys with even lower levels of phosphorus and boron. Atom probe analysis further found that much of the phosphorus, boron, and carbon segregated to grain boundaries. Creep curves comparing the alloys with high levels of phosphorus and boron and alloys with low levels of phosphorus and boron show a large difference in strain rate in the first hours of the test. These results suggest that the boron and phosphorus may have a direct effect on dislocation mobility by some pinning mechanism.

  9. Effects of chronic boron exposure on semen profile.

    PubMed

    Korkmaz, Mehmet; Yenigün, Mehmet; Bakırdere, Sezgin; Ataman, Osman Yavuz; Keskin, Sıddık; Müezzinoğlu, Talha; Lekili, Murat

    2011-11-01

    The possible changes in semen quality were studied in men living in a boron mining area. The subjects in the boron group had exposure to boron at an average level of 6.5 mg/day, as determined by urinary analysis. The results obtained by the boron group were compared to those obtained for the control group whose subjects were living in the same geographical area but away from the boron region; average exposure level was 1.4 mg/day for this group. The semen samples were analyzed according to the recommendations of the World Health Organization. Boron levels were established in the water samples obtained from various locations in the study region. In the boron mining fields where the subjects in the boron group live, water samples contained boron in the range of 1.4-6.5 mg/L, while the values were <0.01 mg/L for the water samples obtained from the region where the subjects of the control group reside. No negative effects were found in the sperm samples obtained from the subjects of the boron group.

  10. Materials Development for Boron Phosphide Based Neutron Detectors: Final Technical Report

    SciTech Connect

    Edgar, James Howard

    2014-09-09

    The project goal was to improve the quality of boron phosphide (BP) by optimizing its epitaxial growth on single crystal substrates and by producing bulk BP single crystals with low dislocation densities. BP is potentially a good semiconductor for high efficiency solid state neutron detectors by combining neutron capture and charge creation within the same volume. The project strategy was to use newly available single crystal substrates, silicon carbide and aluminum nitride, engineered to produce the best film properties. Substrate variables included the SiC polytype, crystallographic planes, misorientation of the substrate surface (tilt direction and magnitude) from the major crystallographic plane, and surface polarity (Si and C). The best films were (111)BP on silicon-face (0001) 4H-SiC misoriented 4° in the [1-100] direction, and BP on (100) and (111) 3C-SiC/Si; these substrates resulted in films that were free of in-plane twin defects, as determined by x-ray topography. The impact of the deposition temperature was also assessed: increasing the temperature from 1000 °C to 1200 °C produced films that were more ordered and more uniform, and the size of individual grains increased by more than a factor of twenty. The BP films were free of other compounds such as icosahedral boron phosphide (B12P2) over the entire temperature range, as established by Raman spectroscopy. The roughness of the BP films was reduced by increasing the phosphine to diborane ratio from 50 to 200. Bulk crystals were grown by reacting boron dissolved in nickel with phosphorus vapor to precipitate BP. Crystals with dimensions up to 2 mm were produced.

  11. Boron nitride nanotubes and nanoplatelets as reinforcing agents of polymeric matrices for bone tissue engineering.

    PubMed

    Farshid, Behzad; Lalwani, Gaurav; Shir Mohammadi, Meisam; Simonsen, John; Sitharaman, Balaji

    2017-02-01

    This study investigates the mechanical properties and in vitro cytotoxicity of one- and two-dimensional boron nitride nanomaterials-reinforced biodegradable polymeric nanocomposites. Poly(propylene fumarate) (PPF) nanocomposites were fabricated using crosslinking agent N-vinyl pyrrolidone and inorganic nanomaterials: boron nitride nanotubes (BNNTs) and boron nitride nanoplatelets (BNNPs) dispersed at 0.2 wt % in the polymeric matrix. The incorporation of BNNPs and BNNTs resulted in a ∼38 and ∼15% increase in compressive (Young's) modulus, and ∼31 and ∼6% increase in compressive yield strength compared to PPF control, respectively. The nanocomposites showed a time-dependent increased protein adsorption for collagen I protein. The cytotoxicity evaluation of aqueous BNNT and BNNP dispersions (at 1-100 μg/mL concentrations) using murine MC3T3 preosteoblast cells showed ∼73-99% viability. The cytotoxicity evaluation of media extracts of nanocomposites before crosslinking, after crosslinking, and upon degradation (using 1×-100× dilutions) showed dose-dependent cytotoxicity responses. Crosslinked nanocomposites showed excellent (∼79-100%) cell viability, cellular attachment (∼57-67%), and spreading similar to cells grown on the surface of tissue culture polystyrene control. The media extracts of degradation products showed a dose-dependent cytotoxicity. The favorable cytocompatibility results in combination with improved mechanical properties of BNNT and BNNP nanocomposites opens new avenues for further in vitro and in vivo safety and efficacy studies towards bone tissue engineering applications. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 406-419, 2017.

  12. Development of neuraminidase detection using gold nanoparticles boron-doped diamond electrodes.

    PubMed

    Wahyuni, Wulan T; Ivandini, Tribidasari A; Saepudin, Endang; Einaga, Yasuaki

    2016-03-15

    Gold nanoparticles-modified boron-doped diamond (AuNPs-BDD) electrodes, which were prepared with a self-assembly deposition of AuNPs at amine-terminated boron-doped diamond, were examined for voltammetric detection of neuraminidase (NA). The detection method was performed based on the difference of electrochemical responses of zanamivir at gold surface before and after the reaction with NA in phosphate buffer solution (PBS, pH 5.5). A linear calibration curve for zanamivir in 0.1 M PBS in the absence of NA was achieved in the concentration range of 1 × 10(-6) to 1 × 10(-5) M (R(2) = 0.99) with an estimated limit of detection (LOD) of 2.29 × 10(-6) M. Furthermore, using its reaction with 1.00 × 10(-5) M zanamivir, a linear calibration curve of NA can be obtained in the concentration range of 0-12 mU (R(2) = 0.99) with an estimated LOD of 0.12 mU. High reproducibility was shown with a relative standard deviation (RSD) of 1.14% (n = 30). These performances could be maintained when the detection was performed in mucin matrix. Comparison performed using gold-modified BDD (Au-BDD) electrodes suggested that the good performance of the detection method is due to the stability of the gold particles position at the BDD surface.

  13. From Boron Cluster to Two-Dimensional Boron Sheet on Cu(111) Surface: Growth Mechanism and Hole Formation

    PubMed Central

    Liu, Hongsheng; Gao, Junfeng; Zhao, Jijun

    2013-01-01

    As attractive analogue of graphene, boron monolayers have been theoretically predicted. However, due to electron deficiency of boron atom, synthesizing boron monolayer is very challenging in experiments. Using first-principles calculations, we explore stability and growth mechanism of various boron sheets on Cu(111) substrate. The monotonic decrease of formation energy of boron cluster BN with increasing cluster size and low diffusion barrier for a single B atom on Cu(111) surface ensure continuous growth of two-dimensional (2D) boron cluster. During growth process, hexagonal holes can easily arise at the edge of a 2D triangular boron cluster and then diffuse entad. Hence, large-scale boron monolayer with mixed hexagonal-triangular geometry can be obtained via either depositing boron atoms directly on Cu(111) surface or soft landing of small planar BN clusters. Our theoretical predictions would stimulate further experiments of synthesizing boron sheets on metal substrates and thus enrich the variety of 2D monolayer materials. PMID:24241341

  14. Boron Arsenide and Boron Phosphide for High Temperature and Luminescent Devices. [semiconductor devices - crystal growth/crystal structure

    NASA Technical Reports Server (NTRS)

    Chu, T. L.

    1975-01-01

    The crystal growth of boron arsenide and boron phosphide in the form of bulk crystals and epitaxial layers on suitable substrates is discussed. The physical, chemical, and electrical properties of the crystals and epitaxial layers are examined. Bulk crystals of boron arsenide were prepared by the chemical transport technique, and their carrier concentration and Hall mobility were measured. The growth of boron arsenide crystals from high temperature solutions was attempted without success. Bulk crystals of boron phosphide were also prepared by chemical transport and solution growth techniques. Techniques required for the fabrication of boron phosphide devices such as junction shaping, diffusion, and contact formation were investigated. Alloying techniques were developed for the formation of low-resistance ohmic contacts to boron phosphide. Four types of boron phosphide devices were fabricated: (1) metal-insulator-boron phosphide structures, (2) Schottky barriers; (3) boron phosphide-silicon carbide heterojunctions; and (4) p-n homojunctions. Easily visible red electroluminescence was observed from both epitaxial and solution grown p-n junctions.

  15. Boron-enriched streptavidin potentially useful as a component of boron carriers for neutron capture therapy of cancer.

    PubMed

    Sano, T

    1999-01-01

    A boron-enriched streptavidin has been prepared by chemical conjugation of a boron-rich compound, B(12)H(11)SH(2)(-) (BSH), to a genetically engineered streptavidin variant. The streptavidin variant used has 20 cysteine residues per molecule, derived from a C-terminal cysteine stretch consisting of five cysteine residues per subunit. Because natural streptavidin has no cysteine residues, the reactive sulfhydryl groups of the cysteine stretch serve as unique conjugation sites for sulfhydryl chemistry. BSH was conjugated irreversibly to the sulfhydryl groups of the streptavidin variant via a sulfhydryl-specific homobifunctional chemical cross-linker. Quantitative boron analysis indicates that the resulting streptavidin-BSH conjugate carries approximately 230 boron atoms/molecule. This indicates that the chemical conjugation of BSH to the streptavidin variant was highly specific and efficient because this method should allow the conjugation of a maximum of 240 boron atoms/streptavidin molecule. This boron-enriched streptavidin retained both full biotin-binding ability and tetrameric structure, suggesting that the conjugation of BSH has little, if any, effect on the fundamental properties of streptavidin. This boron-enriched streptavidin should be very useful as a component of targetable boron carriers for neutron capture therapy of cancer. For example, a monoclonal antibody against a tumor-associated antigen can be attached tightly to the boron-enriched streptavidin upon simple biotinylation, and the resulting conjugate could be used to target boron to tumor cells on which the tumor-associated antigen is overexpressed.

  16. A global strategy for road building.

    PubMed

    Laurance, William F; Clements, Gopalasamy Reuben; Sloan, Sean; O'Connell, Christine S; Mueller, Nathan D; Goosem, Miriam; Venter, Oscar; Edwards, David P; Phalan, Ben; Balmford, Andrew; Van Der Ree, Rodney; Arrea, Irene Burgues

    2014-09-11

    The number and extent of roads will expand dramatically this century. Globally, at least 25 million kilometres of new roads are anticipated by 2050; a 60% increase in the total length of roads over that in 2010. Nine-tenths of all road construction is expected to occur in developing nations, including many regions that sustain exceptional biodiversity and vital ecosystem services. Roads penetrating into wilderness or frontier areas are a major proximate driver of habitat loss and fragmentation, wildfires, overhunting and other environmental degradation, often with irreversible impacts on ecosystems. Unfortunately, much road proliferation is chaotic or poorly planned, and the rate of expansion is so great that it often overwhelms the capacity of environmental planners and managers. Here we present a global scheme for prioritizing road building. This large-scale zoning plan seeks to limit the environmental costs of road expansion while maximizing its benefits for human development, by helping to increase agricultural production, which is an urgent priority given that global food demand could double by mid-century. Our analysis identifies areas with high environmental values where future road building should be avoided if possible, areas where strategic road improvements could promote agricultural development with relatively modest environmental costs, and 'conflict areas' where road building could have sizeable benefits for agriculture but with serious environmental damage. Our plan provides a template for proactively zoning and prioritizing roads during the most explosive era of road expansion in human history.

  17. Photogrammetric Techniques for Road Surface Analysis

    NASA Astrophysics Data System (ADS)

    Knyaz, V. A.; Chibunichev, A. G.

    2016-06-01

    The quality and condition of a road surface is of great importance for convenience and safety of driving. So the investigations of the behaviour of road materials in laboratory conditions and monitoring of existing roads are widely fulfilled for controlling a geometric parameters and detecting defects in the road surface. Photogrammetry as accurate non-contact measuring method provides powerful means for solving different tasks in road surface reconstruction and analysis. The range of dimensions concerned in road surface analysis can have great variation from tenths of millimetre to hundreds meters and more. So a set of techniques is needed to meet all requirements of road parameters estimation. Two photogrammetric techniques for road surface analysis are presented: for accurate measuring of road pavement and for road surface reconstruction based on imagery obtained from unmanned aerial vehicle. The first technique uses photogrammetric system based on structured light for fast and accurate surface 3D reconstruction and it allows analysing the characteristics of road texture and monitoring the pavement behaviour. The second technique provides dense 3D model road suitable for road macro parameters estimation.

  18. One-dimensional boron nanostructures: Prediction, synthesis, characterizations, and applications.

    PubMed

    Tian, Jifa; Xu, Zhichuan; Shen, Chengmin; Liu, Fei; Xu, Ningsheng; Gao, Hong-Jun

    2010-08-01

    One-dimensional (1D) boron nanostructures are very potential for nanoscale electronic devices since their physical properties including electric transport and field emission have been found very promising as compared to other well-developed 1D nanomaterials. In this article, we review the current progress that has been made on 1D boron nanostructures in terms of theoretical prediction, synthetic techniques, characterizations and potential applications. To date, the synthesis of 1D boron nanostructures has been well-developed. The popular structures include nanowires, nanobelts, and nanocones. Some of these 1D nanostructures exhibited improved electric transport properties over bulk boron materials as well as promising field emission properties. By current experimental findings, 1D boron nanostructures are promising to be one of core materials for future nanodevices. More efforts are expected to be made in future on the controlled growth of 1D boron nanostructures and tailoring their physical properties.

  19. A study of boron adsorption onto activated sludge.

    PubMed

    Fujita, Yuichiro; Hata, Takayosi; Nakamaru, Makoto; Iyo, Toru; Yoshino, Tsuneo; Shimamura, Tadashi

    2005-08-01

    Boron adsorption onto activated sludge was investigated using bench-scale reactors under simulated wastewater treatment conditions. Two experiments, continuous flow and batch, were performed. Boron concentrations were determined by means of inductively coupled plasma mass spectrometry. The results of the continuous-flow experiment indicated that a small amount of boron accumulated on the activated sludge and its concentration in the sludge depended on the nature of the biota in the sludge. Freundlich and Langmuir isotherm plots generated using the data from the batch experiment indicated that boron was adsorbed onto rather than absorbed into the sludge. The Freundlich constants, k and 1/n, were determined to be 26 mg/kg and 0.87. These values indicate that activated sludge has a limited capacity for boron adsorption and thus utilization of the excess sludge for farmland may not be toxic to plant at least boron concern.

  20. Combined effect of boron and salinity on water transport

    PubMed Central

    del Carmen Martínez-Ballesta, Maria; Bastías, Elizabeth

    2008-01-01

    Boron toxicity is an important disorder that can limit plant growth on soils of arid and semi arid environments throughout the world. Although there are several reports about the combined effect of salinity and boron toxicity on plant growth and yield, there is no consensus about the experimental results. A general antagonistic relationship between boron excess and salinity has been observed, however the mechanisms for this interaction is not clear and several options can be discussed. In addition, there is no information, concerning the interaction between boron toxicity and salinity with respect to water transport and aquaporins function in the plants. We recently documented in the highly boron- and salt-tolerant the ecotype of Zea mays L. amylacea from Lluta valley in Northern Chile that under salt stress, the activity of specific membrane components can be influenced directly by boron, regulating the water uptake and water transport through the functions of certain aquaporin isoforms. PMID:19704850

  1. Boron nitride - Composition, optical properties, and mechanical behavior

    NASA Technical Reports Server (NTRS)

    Pouch, John J.; Alterovitz, Samuel A.; Miyoshi, Kazuhisa; Warner, Joseph D.

    1987-01-01

    A low energy ion beam deposition technique was used to grow boron nitride films on quartz, germanium, silicon, gallium arsenide, and indium phosphate. The film structure was amorphous with evidence of a hexagonal phase. The peak boron concentration was 82 at. percent. The carbon and oxygen impurities were in the 5 to 8 at. percent range. Boron-nitrogen and boron-boron bonds were revealed by X-ray photoelectron spectroscopy. The index of refraction varied from 1.65 to 1.67 for films deposited on III-V compound semiconductors. The coefficient of friction for boron nitride in sliding contact with diamond was less than 0.1. The substrate was silicon.

  2. Boron nitride: Composition, optical properties and mechanical behavior

    NASA Technical Reports Server (NTRS)

    Pouch, John J.; Alterovitz, Samuel A.; Miyoshi, Kazuhisa; Warner, Joseph D.

    1987-01-01

    A low energy ion beam deposition technique was used to grow boron nitride films on quartz, germanium, silicon, gallium arsenide, and indium phosphate. The film structure was amorphous with evidence of a hexagonal phase. The peak boron concentration was 82 at %. The carbon and oxygen impurities were in the 5 to 8 at % range. Boron-nitrogen and boron-boron bonds were revealed by X-ray photoelectron spectroscopy. The index of refraction varied from 1.65 to 1.67 for films deposited on III-V compound semiconductors. The coefficient of friction for boron nitride in sliding contact with diamond was less than 0.1. The substrate was silicon.

  3. Building lunar roads - An overview

    NASA Astrophysics Data System (ADS)

    Rutledge, Bennett

    The problems involved in constructing lunar roads are explored. The main challenges are airlessness, low gravity, and solar effects, especially temperature extremes. Also involved are the expense of delivering equipment and material to the job site (especially for bridges and other structures), obtaining skilled labor, and providing maintenance. The lunar road will most likely be gravel, but with the size of the material closer to cobblestone to reduce scattering. They will probably be very winding, even on the flats, and feature numerous bridges and some cuts. This traffic will be mostly automatic or teleoperated cargo carriers with a handful of shirtsleeve-pressurized 'passenger cars' large enough to live in for several days.

  4. Strongly Phosphorescent Transition Metal π-Complexes of Boron-Boron Triple Bonds.

    PubMed

    Braunschweig, Holger; Dellermann, Theresa; Dewhurst, Rian D; Hupp, Benjamin; Kramer, Thomas; Mattock, James D; Mies, Jan; Phukan, Ashwini K; Steffen, Andreas; Vargas, Alfredo

    2017-03-27

    Herein are reported the first π-complexes of compounds with boron-boron triple bonds with transition metals, in this case Cu(I). Three different compounds were isolated that differ in the number of copper atoms bound to the BB unit. Metalation of the B-B triple bonds causes lengthening of the B-B and B-C(NHC) bonds, as well as large upfield shifts of the (11)B NMR signals, suggesting greater orbital interactions between the boron and transition metal atoms than those observed with recently published diboryne/alkali metal cation complexes. In contrast to previously reported fluorescent copper(I) π-complexes of boron-boron double bonds, the Cun-π-diboryne compounds (n = 2, 3) show intense phosphorescence in the red to near-IR region from their triplet excited states, according to their microsecond lifetimes, with quantum yields of up to 58%. While the Cu diborene bond is dominated by electrostatic interactions, giving rise to S1 and T1 states of pure IL(π-π*) nature, DFT studies show that the Cu(I) π-complexes of diborynes reported herein exhibit enhanced metal d orbital contributions to HOMO and HOMO-1, which results in S1 and T1 having significant MLCT character, enabling strong spin-orbit coupling for highly efficient intersystem-crossing S1 → Tn and phosphorescence T1 → S0.

  5. Receptor-mediated uptake of boron-rich neuropeptide y analogues for boron neutron capture therapy.

    PubMed

    Ahrens, Verena M; Frank, René; Boehnke, Solveig; Schütz, Christian L; Hampel, Gabriele; Iffland, Dorothée S; Bings, Nicolas H; Hey-Hawkins, Evamarie; Beck-Sickinger, Annette G

    2015-01-01

    Peptidic ligands selectively targeting distinct G protein-coupled receptors that are highly expressed in tumor tissue represent a promising approach in drug delivery. Receptor-preferring analogues of neuropeptide Y (NPY) bind and activate the human Y1 receptor subtype (hY1 receptor), which is found in 90% of breast cancer tissue and in all breast-cancer-derived metastases. Herein, novel highly boron-loaded Y1 -receptor-preferring peptide analogues are described as smart shuttle systems for carbaboranes as (10) B-containing moieties. Various positions in the peptide were screened for their susceptibility to carbaborane modification, and the most promising positions were chosen to create a multi-carbaborane peptide containing 30 boron atoms per peptide with excellent activation and internalization patterns at the hY1 receptor. Boron uptake studies by inductively coupled plasma mass spectrometry revealed successful uptake of the multi-carbaborane peptide into hY1 -receptor-expressing cells, exceeding the required amount of 10(9) boron atoms per cell. This result demonstrates that the NPY/hY receptor system can act as an effective transport system for boron-containing moieties.

  6. Potential of using boric acid as a boron drug for boron neutron capture therapy for osteosarcoma.

    PubMed

    Hsu, C F; Lin, S Y; Peir, J J; Liao, J W; Lin, Y C; Chou, F I

    2011-12-01

    Osteosarcoma is a malignant tumor commonly found in human and animals. The ability of boric acid (BA) to accumulate in osteosarcoma due to the mechanism of the bone formation of cancer cells would make boron neutron capture therapy (BNCT) an alternative therapy for osteosarcoma. This study evaluated the feasibility of using BA as the boron drug for BNCT of bone cancer. The cytotoxicity of BA to L929 cells exceeded that of UMR-106 cells. With 25 μg (10)B/mL medium of BA treatment, the boron concentration in UMR-106 cells was higher than that in L929 cells. The biodistribution and pharmacokinetics of BA in Sprague-Dawley (SD) rats were studied by administrating 25 mg (10)B/kg body weight to SD rats. Blood boron level decreased rapidly within one hour after BA injection. Boron concentration in the long bone was 4-6 time higher than that of blood. Results of this study suggest that BA may be a potential drug for BNCT for osteosarcoma.

  7. Apparatus for the production of boron nitride nanotubes

    SciTech Connect

    Smith, Michael W; Jordan, Kevin

    2014-06-17

    An apparatus for the large scale production of boron nitride nanotubes comprising; a pressure chamber containing; a continuously fed boron containing target; a source of thermal energy preferably a focused laser beam; a cooled condenser; a source of pressurized nitrogen gas; and a mechanism for extracting boron nitride nanotubes that are condensed on or in the area of the cooled condenser from the pressure chamber.

  8. First Principles Atomistic Model for Carbon-Doped Boron Suboxide

    DTIC Science & Technology

    2014-09-01

    First Principles Atomistic Model for Carbon-Doped Boron Suboxide by Amol B Rahane, Jennifer S Dunn, and Vijay Kumar ARL-TR-7106...2014 First Principles Atomistic Model for Carbon-Doped Boron Suboxide Amol B Rahane Dr Vijay Kumar Foundation 1969 Sector 4 Gurgaon...Final 3. DATES COVERED (From - To) October 2013–July 2014 4. TITLE AND SUBTITLE First Principles Atomistic Model for Carbon-Doped Boron Suboxide

  9. Low-loss binder for hot pressing boron nitride

    DOEpatents

    Maya, Leon

    1991-01-01

    Borazine derivatives used as low-loss binders and precursors for making ceramic boron nitride structures. The derivative forms the same composition as the boron nitride starting material, thereby filling the voids with the same boron nitride material upon forming and hot pressing. The derivatives have a further advantage of being low in carbon thus resulting in less volatile byproduct that can result in bubble formation during pressing.

  10. Boron compounds as anion binding agents for nonaqueous battery electrolytes

    DOEpatents

    Lee, Hung Sui; Yang, Xia-Oing; McBreen, James; Xiang, Caili

    2000-02-08

    Novel fluorinated boron-based compounds which act as anion receptors in non-aqueous battery electrolytes are provided. When added to non-aqueous battery electrolytes, the fluorinated boron-based compounds of the invention enhance ionic conductivity and cation transference number of non-aqueous electrolytes. The fluorinated boron-based anion receptors include borane and borate compounds bearing different fluorinated alkyl and aryl groups.

  11. Nonlinear response of unidirectional boron/aluminum

    NASA Technical Reports Server (NTRS)

    Pindera, M.-J.; Herakovich, C. T.; Becker, W.; Aboudi, J.

    1990-01-01

    Experimental results obtained for unidirectional boron/aluminum subjected to combined loading using off-axis tension, compression and Iosipescu shear specimens are correlated with a nonlinear micromechanics model. It is illustrated that the nonlinear response in the principal material directions is markedly influenced by the different loading modes and different ratios of the applied stress components. The observed nonlinear response under pure and combined loading is discussed in terms of initial yielding, subsequent hardening, stress-interaction effects and unloading-reloading characteristics. The micromechanics model is based on the concept of a repeating unit cell representative of the composite-at-large and employs the unified theory of Bodner and Partom to model the inelastic response of the matrix. It is shown that the employed micromechanics model is sufficiently general to predict the observed nonlinear response of unidirectional boron/aluminum with good accuracy.

  12. Boron Nitride Nanotube: Synthesis and Applications

    NASA Technical Reports Server (NTRS)

    Tiano, Amanda L.; Park, Cheol; Lee, Joseph W.; Luong, Hoa H.; Gibbons, Luke J.; Chu, Sang-Hyon; Applin, Samantha I.; Gnoffo, Peter; Lowther, Sharon; Kim, Hyun Jung; Danehy, Paul M.; Inman, Jennifer A.; Jones, Stephen B.; Kang, Jin Ho; Sauti, Godfrey; Thibeault, Sheila A.; Yamakov, Vesselin; Wise, Kristopher E.; Su, Ji; Fay, Catharine C.

    2014-01-01

    Scientists have predicted that carbon's immediate neighbors on the periodic chart, boron and nitrogen, may also form perfect nanotubes, since the advent of carbon nanotubes (CNTs) in 1991. First proposed then synthesized by researchers at UC Berkeley in the mid 1990's, the boron nitride nanotube (BNNT) has proven very difficult to make until now. Herein we provide an update on a catalyst-free method for synthesizing highly crystalline, small diameter BNNTs with a high aspect ratio using a high power laser under a high pressure and high temperature environment first discovered jointly by NASA/NIA JSA. Progress in purification methods, dispersion studies, BNNT mat and composite formation, and modeling and diagnostics will also be presented. The white BNNTs offer extraordinary properties including neutron radiation shielding, piezoelectricity, thermal oxidative stability (> 800 C in air), mechanical strength, and toughness. The characteristics of the novel BNNTs and BNNT polymer composites and their potential applications are discussed.

  13. Natural Radioactivity of Boron Added Clay Samples

    SciTech Connect

    Akkurt, I.; Guenoglu, K.; Canakcii, H.; Mavi, B.

    2011-12-26

    Clay, consisting fine-grained minerals, is an interesting materials and can be used in a variety of different fields especially in dermatology application. Using clay such a field it is important to measure its natural radioactivity. Thus the purpose of this study is to measure {sup 226}Ra, {sup 232}Th and {sup 40}K concentration in clay samples enriched with boron. Three different types of clay samples were prepared where boron is used in different rate. The measurements have been determined using a gamma-ray spectrometry consists of a 3''x3'' NaI(Tl) detector. From the measured activity the radium equivalent activities (Ra{sub eq}), external hazard index (H{sub ex}), absorbed dose rate in air (D) and annual effective dose (AED) have also been obtained.

  14. Natural Radioactivity of Boron Added Clay Samples

    NASA Astrophysics Data System (ADS)

    Akkurt, I.; ćanakciı, H.; Mavi, B.; Günoǧlu, K.

    2011-12-01

    Clay, consisting fine-grained minerals, is an interesting materials and can be used in a variety of diferent fields especially in dermatology application. Using clay such a field it is important to measure its natural radioacitivty. Thus the purpose of this study is to measure 226Ra, 232Th and 40K concentration in clay samples enriched with boron. Three different types of clay samples were prepared where boron is used in different rate. The measurements have been determined using a gamma-ray spectrometry consists of a 3″×3″ NaI(Tl) detector. From the measured activity the radium equivalent activities (Raeq), external hazard index (Hex), absorbed dose rate in air (D) and annual effective dose (AED) have also been obtained.

  15. Boron-10 ABUNCL Models of Fuel Testing

    SciTech Connect

    Siciliano, Edward R.; Lintereur, Azaree T.; Kouzes, Richard T.; Ely, James H.

    2013-10-01

    The Department of Energy Office of Nuclear Safeguards and Security (NA-241) is supporting the project Coincidence Counting With Boron-Based Alternative Neutron Detection Technology at Pacific Northwest National Laboratory (PNNL) for the development of a 3He proportional counter alternative neutron coincidence counter. The goal of this project is to design, build and demonstrate a system based upon 10B-lined proportional tubes in a configuration typical for 3He-based coincidence counter applications. This report provides results from MCNP simulations of the General Electric Reuter-Stokes Alternative Boron-Based Uranium Neutron Coincidence Collar (ABUNCL) active configuration model with fuel pins previously measured at Los Alamos National Laboratory. A comparison of the GE-ABUNCL simulations and simulations of 3He based UNCL-II active counter (the system for which the GE-ABUNCL was targeted to replace) with the same fuel pin assemblies is also provided.

  16. Method for fabricating boron carbide articles

    DOEpatents

    Ardary, Zane L.; Reynolds, Carl D.

    1980-01-01

    The present invention is directed to the fabrication of boron carbide articles having length-to-diameter or width ratios greater than 2 to 1. The process of the present invention is practiced by the steps comprising hot pressing boron carbide powder into article segments or portions in which the segments have a length-to-diameter or width ratio less than 1.5, aligning a plurality of the initially hot-pressed segments in a hot-pressing die with the end surfaces of the segments placed in intimate contact with one another, and then hot pressing the aligned segments into an article of the desired configuration. The resulting article exhibits essentially uniform density throughout the structure with the bonds between the segments being equivalent in hardness, strength, and density to the remainder of the article.

  17. Boron nitride encapsulated graphene infrared emitters

    NASA Astrophysics Data System (ADS)

    Barnard, H. R.; Zossimova, E.; Mahlmeister, N. H.; Lawton, L. M.; Luxmoore, I. J.; Nash, G. R.

    2016-03-01

    The spatial and spectral characteristics of mid-infrared thermal emission from devices containing a large area multilayer graphene layer, encapsulated using hexagonal boron nitride, have been investigated. The devices were run continuously in air for over 1000 h, with the emission spectrum covering the absorption bands of many important gases. An approximate solution to the heat equation was used to simulate the measured emission profile across the devices yielding an estimated value of the characteristic length, which defines the exponential rise/fall of the temperature profile across the device, of 40 μm. This is much larger than values obtained in smaller exfoliated graphene devices and reflects the device geometry, and the increase in lateral heat conduction within the devices due to the multilayer graphene and boron nitride layers.

  18. Techniques for increasing boron fiber fracture strain

    NASA Technical Reports Server (NTRS)

    Dicarlo, J. A.

    1977-01-01

    Improvement in the strain-to-failure of CVD boron fibers is shown possible by contracting the tungsten boride core region and its inherent flaws. The results of three methods are presented in which etching and thermal processing techniques were employed to achieve core flaw contraction by internal stresses available in the boron sheath. After commercially and treatment induced surface flaws were removed from 203 micrometers (8 mil) fibers, the core flaw was observed to be essentially the only source of fiber fracture. Thus, fiber strain-to-failure was found to improve by an amount equal to the treatment induced contraction on the core flaw. Commercial feasibility considerations suggest as the most cost effective technique that method in which as-produced fibers are given a rapid heat treatment above 700 C. Preliminary results concerning the contraction kinetics and fracture behavior observed are presented and discussed both for high vacuum and argon gas heat treatment environments.

  19. Asymmetric twins in rhombohedral boron carbide

    SciTech Connect

    Fujita, Takeshi Guan, Pengfei; Madhav Reddy, K.; Hirata, Akihiko; Guo, Junjie; Chen, Mingwei

    2014-01-13

    Superhard materials consisting of light elements have recently received considerable attention because of their ultrahigh specific strength for a wide range of applications as structural and functional materials. However, the failure mechanisms of these materials subjected to high stresses and dynamic loading remain to be poorly known. We report asymmetric twins in a complex compound, boron carbide (B{sub 4}C), characterized by spherical-aberration-corrected transmission electron microscopy. The atomic structure of boron-rich icosahedra at rhombohedral vertices and cross-linked carbon-rich atomic chains can be clearly visualized, which reveals unusual asymmetric twins with detectable strains along the twin interfaces. This study offers atomic insights into the structure of twins in a complex material and has important implications in understanding the planar defect-related failure of superhard materials under high stresses and shock loading.

  20. Boron nitride nanotube: synthesis and applications

    NASA Astrophysics Data System (ADS)

    Tiano, Amanda L.; Park, Cheol; Lee, Joseph W.; Luong, Hoa H.; Gibbons, Luke J.; Chu, Sang-Hyon; Applin, Samantha; Gnoffo, Peter; Lowther, Sharon; Kim, Hyun Jung; Danehy, Paul M.; Inman, Jennifer A.; Jones, Stephen B.; Kang, Jin Ho; Sauti, Godfrey; Thibeault, Sheila A.; Yamakov, Vesselin; Wise, Kristopher E.; Su, Ji; Fay, Catharine C.

    2014-04-01

    Scientists have predicted that carbon's immediate neighbors on the periodic chart, boron and nitrogen, may also form perfect nanotubes, since the advent of carbon nanotubes (CNTs) in 1991. First proposed then synthesized by researchers at UC Berkeley in the mid 1990's, the boron nitride nanotube (BNNT) has proven very difficult to make until now. Herein we provide an update on a catalyst-free method for synthesizing highly crystalline, small diameter BNNTs with a high aspect ratio using a high power laser under a high pressure and high temperature environment first discovered jointly by NASA/NIA/JSA. Progress in purification methods, dispersion studies, BNNT mat and composite formation, and modeling and diagnostics will also be presented. The white BNNTs offer extraordinary properties including neutron radiation shielding, piezoelectricity, thermal oxidative stability (> 800°C in air), mechanical strength, and toughness. The characteristics of the novel BNNTs and BNNT polymer composites and their potential applications are discussed.

  1. Gravel Roads: Maintenance and Design Manual

    EPA Pesticide Factsheets

    This manual was developed with a major emphasis on the maintenance of gravel roads, including some basic design elements. The purpose of the manual is to provide clear and helpful information for doing a better job of maintaining gravel roads.

  2. 35. PRATER GRADE ROAD VIEW, FACING NW. NOTE WEATHERING STEEL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    35. PRATER GRADE ROAD VIEW, FACING NW. NOTE WEATHERING STEEL RAIL AND ROAD CUT IN DISTANCE. MONTEZUMA VALLEY OVERLOOK IS JUST TO RIGHT OF DISTANT ROAD CUT. - Mesa Verde National Park Main Entrance Road, Cortez, Montezuma County, CO

  3. 3. ENVIRONMENT, FROM SOUTH, SHOWING RIVER ROAD RIDGE CARRYING CASSELMAN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. ENVIRONMENT, FROM SOUTH, SHOWING RIVER ROAD RIDGE CARRYING CASSELMAN RIVER ROAD OVER CASSELMAN RIVER - River Road Bridge, Crossing Casselman River on Casselman River Road, Grantsville, Garrett County, MD

  4. 1. AERIAL VIEW, SHOWING GLENDALE ROAD BRIDGE WITHIN ITS SETTING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. AERIAL VIEW, SHOWING GLENDALE ROAD BRIDGE WITHIN ITS SETTING AT GLENDALE ROAD CROSSING OF DEEP CREEK LAKE (PHOTOGRAPH BY RUTHVAN MORROW) - Glendale Road Bridge, Spanning Deep Creek Lake on Glendale Road, McHenry, Garrett County, MD

  5. 2. AERIAL VIEW, SHOWING GLENDALE ROAD BRIDGE WITHIN ITS SETTING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. AERIAL VIEW, SHOWING GLENDALE ROAD BRIDGE WITHIN ITS SETTING AT GLENDALE ROAD CROSSING OF DEEP CREEK LAKE (PHOTOGRAPH BY RUTHVAN MORROW) - Glendale Road Bridge, Spanning Deep Creek Lake on Glendale Road, McHenry, Garrett County, MD

  6. 2. CONTEXTUAL VIEW OF WHITE ROCK ROAD, VIEW OF PROJECT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. CONTEXTUAL VIEW OF WHITE ROCK ROAD, VIEW OF PROJECT AREA LOOKING TOWARD ELEVATED INTERSECTION OF LATROBE ROAD; VIEW TO SOUTHWEST. - Placerville Road, White Rock Road between Clarksville & White Rock, El Dorado Hills, El Dorado County, CA

  7. 6. ELEVATED, OBLIQUE VIEW OF INTERSECTION INFRASTRUCTURE AT LATROBE ROAD ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. ELEVATED, OBLIQUE VIEW OF INTERSECTION INFRASTRUCTURE AT LATROBE ROAD AND WHITE ROCK ROAD; VIEW TO SOUTHWEST. - Placerville Road, White Rock Road between Clarksville & White Rock, El Dorado Hills, El Dorado County, CA

  8. 1. CONTEXTUAL VIEW OF WHITE ROCK ROAD, VIEW OF PROJECT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. CONTEXTUAL VIEW OF WHITE ROCK ROAD, VIEW OF PROJECT AREA WITH INTERSECTION OF LATROBE ROAD SEEN IN UPPER LEFT; VIEW TO NORTHEAST. - Placerville Road, White Rock Road between Clarksville & White Rock, El Dorado Hills, El Dorado County, CA

  9. Old Big Oak Flat Road at intersection with New Tioga ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Old Big Oak Flat Road at intersection with New Tioga Road. Note gate for road to Tamarack Campground - Big Oak Flat Road, Between Big Oak Flat Entrance & Merced River, Yosemite Village, Mariposa County, CA

  10. The prospects for composites based on boron fibers

    NASA Technical Reports Server (NTRS)

    Naslain, R.

    1978-01-01

    The fabrication of boron filaments and the production of composite materials consisting of boron filaments and organic or metallic matrices are discussed. Problem involving the use of tungsten substrates in the filament fabrication process, the protection of boron fibers with diffusion barrier cladings, and the application of alloy additives in the matrix to lessen the effects of diffusion are considered. Data on the kinetics of the boron fiber/matrix interaction at high temperatures, and the influence of the fiber/matrix interaction on the mechanical properties of the composite are presented.

  11. Switchable Surface Wettability by Using Boronic Ester Chemistry.

    PubMed

    Taleb, Sabri; Noyer, Elisabeth; Godeau, Guilhem; Darmanin, Thierry; Guittard, Frédéric

    2016-01-18

    Here, we report for the first time the use of a boronic ester as an efficient tool for reversible surface post-functionalization. The boronic ester bond allows surfaces to be reversibly switched from hydrophilic to hydrophobic. Based on the well-known boronic acid/glycol affinity, this strategy offers the opportunity to play with surface hydrophobic properties by adding various boronic acids onto substrates bearing glycol groups. The post-functionalization can then be reversed to regenerate the starting glycol surface. This pathway allows for the preparation of various switchable surfaces for a large range of applications in biosensors, liquid transportation, and separation membranes.

  12. Effect of dietary boron on the aging process.

    PubMed

    Massie, H R

    1994-11-01

    Total boron concentrations in Drosophila changed during development and aging. The highest concentration of boron was found during the egg stage, followed by a decline during the larval stages. Newly emerged flies contained 35.5 ppm boron. During the adult stage the boron concentration increased by 52% by 9 weeks of age. Adding excess dietary boron during the adult stage decreased the median life span by 69% at 0.01 M sodium borate and by 21% at 0.001 M sodium borate. Lower concentrations gave small but significant increases in life span. Supplementing a very low boron diet with 0.00025 M sodium borate improved life span by 9.5%. The boron contents of young and old mouse tissues were similar to those of Drosophila and human samples. Boron supplements of 4.3 and 21.6 ppm in the drinking water, however, did not significantly change the life span of old mice fed a diet containing 31.1 ppm boron.

  13. Ecological risk assessment of a wetland exposed to boron

    SciTech Connect

    Powell, R.L.; Kimerle, R.A.; Coyle, G.T.; Best, G.R.

    1997-11-01

    A wetland located in the southeastern portion of the United States was the site of an investigation to determine the potential ecological risk of elevated boron concentrations to the flora and fauna living in the wetland. The conceptual model identified the vegetation as the primary receptor of concern, and thus the vegetation is the focus of this article. Samples of surface water, sediments, and selected vegetation were collected from the study wetland and several nearby reference sites and were analyzed for boron. Concentrations of boron in all three media exceeded reference site concentrations. Boron concentrations were highest near the suspected source but decreased almost to reference-site concentrations near the outer perimeter of the wetland. Some plants appeared stressed with yellowing and necrotic leaves; however, a correlation between tissue boron concentrations and the plant`s visual appearance was not apparent for all species studied. Modeling of the fate of boron indicated that the wetland has likely been at a steady state for many years and that boron concentrations were not expected to increase. It was concluded that no observable adverse ecological impacts to the vegetation could be attributed to boron, nor is it likely that the boron poses an unacceptable risk to the surrounding areas.

  14. Lateral gas phase diffusion length of boron atoms over Si/B surfaces during CVD of pure boron layers

    SciTech Connect

    Mohammadi, V. Nihtianov, S.

    2016-02-15

    The lateral gas phase diffusion length of boron atoms, L{sub B}, along silicon and boron surfaces during chemical vapor deposition (CVD) using diborane (B{sub 2}H{sub 6}) is reported. The value of L{sub B} is critical for reliable and uniform boron layer coverage. The presented information was obtained experimentally and confirmed analytically in the boron deposition temperature range from 700 °C down to 400 °C. For this temperature range the local loading effect of the boron deposition is investigated on the micro scale. A L{sub B} = 2.2 mm was determined for boron deposition at 700 °C, while a L{sub B} of less than 1 mm was observed at temperatures lower than 500 °C.

  15. Anomalous thermal conductivity of monolayer boron nitride

    NASA Astrophysics Data System (ADS)

    Tabarraei, Alireza; Wang, Xiaonan

    2016-05-01

    In this paper, we use nonequilibrium molecular dynamics modeling to investigate the thermal properties of monolayer hexagonal boron nitride nanoribbons under uniaxial strain along their longitudinal axis. Our simulations predict that hexagonal boron nitride shows an anomalous thermal response to the applied uniaxial strain. Contrary to three dimensional materials, under uniaxial stretching, the thermal conductivity of boron nitride nanoribbons first increases rather than decreasing until it reaches its peak value and then starts decreasing. Under compressive strain, the thermal conductivity of monolayer boron nitride ribbons monolithically reduces rather than increasing. We use phonon spectrum and dispersion curves to investigate the mechanism responsible for the unexpected behavior. Our molecular dynamics modeling and density functional theory results show that application of longitudinal tensile strain leads to the reduction of the group velocities of longitudinal and transverse acoustic modes. Such a phonon softening mechanism acts to reduce the thermal conductivity of the nanoribbons. On the other hand, a significant increase in the group velocity (stiffening) of the flexural acoustic modes is observed, which counteracts the phonon softening effects of the longitudinal and transverse modes. The total thermal conductivity of the ribbons is a result of competition between these two mechanisms. At low tensile strain, the stiffening mechanism overcomes the softening mechanism which leads to an increase in the thermal conductivity. At higher tensile strain, the softening mechanism supersedes the stiffening and the thermal conductivity slightly reduces. Our simulations show that the decrease in the thermal conductivity under compressive strain is attributed to the formation of buckling defects which reduces the phonon mean free path.

  16. Electron-Spin Resonance in Boron Carbide

    NASA Technical Reports Server (NTRS)

    Wood, Charles; Venturini, Eugene L.; Azevedo, Larry J.; Emin, David

    1987-01-01

    Samples exhibit Curie-law behavior in temperature range of 2 to 100 K. Technical paper presents studies of electron-spin resonance of samples of hot pressed B9 C, B15 C2, B13 C2, and B4 C. Boron carbide ceramics are refractory solids with high melting temperatures, low thermal conductives, and extreme hardnesses. They show promise as semiconductors at high temperatures and have unusually large figures of merit for use in thermoelectric generators.

  17. New nanoforms of carbon and boron nitride

    NASA Astrophysics Data System (ADS)

    Pokropivny, V. V.; Ivanovskii, A. L.

    2008-10-01

    Data on new carbon nanostructures including those based on fullerenes, nanotubes as well monolithic diamond-like nanoparticles, nanofibres, various nanocomposites, etc., published in the last decade are generalised. The experimental and theoretical data on their atomic and electronic structures, the nature of chemical bonds and physicochemical properties are discussed. These data are compared with the results obtained in studies of nanoforms of boron nitride, an isoelectronic analogue of carbon. Potential fields of applications of the new nanostructures are considered.

  18. Photoelectron Spectroscopy of Aluminum Doped Boron Clusters

    NASA Astrophysics Data System (ADS)

    Li, Wei-Li; Romanescu, Constantin; Wang, Lai-Sheng

    2012-06-01

    Anionic boron clusters have been shown to be planar or quasi-planar up to B21- from a series of combined photoelectron spectroscopy and theoretical studies. All these boron clusters consist of a peripheral ring characterized by strong two-center-two-electron (2c-2e) B-B bonds and one or more interior atoms. The propensity for planarity is due to σ - and π -electron delocalizations throughout the molecular plane, giving rise to concepts of σ - and π -aromaticity. The quasi-planarity, on the other hand, can be mechanical in nature - the circumference of the cluster is too small to fit the inner atoms - even for doubly aromatic clusters. Two questions arise: firstly, can isoelectronic substitution by a single aluminum atom on the outer ring enhance the planarity of quasi-planar structures, and, secondly, can the interior boron atoms be replaced by aluminum? A series of aluminum isoelectronic substitution of boron clusters have been investigated ranging from B7- to B12-. Aluminum turns out to avoid the central position in the all these clusters and enhance the planarity of AlB6- and AlB11- clusters by expanding the peripheral ring. References: [1] C. Romanescu, A. P. Sergeeva, W. L. Li, A. I. Boldyrev and L. S. Wang, {J. Am. Chem. Soc}. {133} (22), 8646-8653 (2011) [2] T. R. Galeev, C. Romanescu, W. L. Li, L. S. Wang and A. I. Boldyrev, {J. Chem. Phys.} {135}, (8) 104301 (2011) [3] W. L. Li, C. Romanescu, T. R. Galeev, L. S. Wang and A. I. Boldyrev, {J. Phys. Chem. A} {115} (38), 10391-10397 (2011)

  19. Immobilization of proteins on boron nitride nanotubes.

    PubMed

    Zhi, Chunyi; Bando, Yoshio; Tang, Chengchun; Golberg, Dmitri

    2005-12-14

    We report for the first time that proteins are immobilized on boron nitride nanotubes. It is found that there is a natural affinity of a protein to BNNT; this means that it can be immobilized on BNNT directly, without usage of an additional coupling reagent. For the most effective immobilization, noncovalently functionalized BNNTs should be used. The effect of immobilization was studied using high-resolution transmission electron microscopy and energy dispersion spectroscopy.

  20. Amorphous Carbon-Boron Nitride Nanotube Hybrids

    NASA Technical Reports Server (NTRS)

    Kim, Jae Woo (Inventor); Siochi, Emilie J. (Inventor); Wise, Kristopher E. (Inventor); Lin, Yi (Inventor); Connell, John (Inventor)

    2016-01-01

    A method for joining or repairing boron nitride nanotubes (BNNTs). In joining BNNTs, the nanotube structure is modified with amorphous carbon deposited by controlled electron beam irradiation to form well bonded hybrid a-C/BNNT structures. In repairing BNNTs, the damaged site of the nanotube structure is modified with amorphous carbon deposited by controlled electron beam irradiation to form well bonded hybrid a-C/BNNT structures at the damage site.

  1. Nanotwins soften boron-rich boron carbide (B13C2)

    NASA Astrophysics Data System (ADS)

    An, Qi; Goddard, William A.

    2017-03-01

    Extensive studies of metals and alloys have observed that nanotwins lead to strengthening, but the role of nanotwins in ceramics is not well established. We compare here the shear strength and the deformation mechanism of nanotwinned boron-rich boron carbide (B13C2) with the perfect crystal under both pure shear and biaxial shear deformations. We find that the intrinsic shear strength of crystalline B13C2 is higher than that of crystalline boron carbide (B4C). But nanotwins in B13C2 lower the strength, making it softer than crystalline B4C. This reduction in strength of nanotwinned B13C2 arises from the interaction of the twin boundary with the C-B-C chains that connect the B12 icosahedra.

  2. Boron-carbide-aluminum and boron-carbide-reactive metal cermets

    DOEpatents

    Halverson, Danny C.; Pyzik, Aleksander J.; Aksay, Ilhan A.

    1986-01-01

    Hard, tough, lightweight boron-carbide-reactive metal composites, particularly boron-carbide-aluminum composites, are produced. These composites have compositions with a plurality of phases. A method is provided, including the steps of wetting and reacting the starting materials, by which the microstructures in the resulting composites can be controllably selected. Starting compositions, reaction temperatures, reaction times, and reaction atmospheres are parameters for controlling the process and resulting compositions. The ceramic phases are homogeneously distributed in the metal phases and adhesive forces at ceramic-metal interfaces are maximized. An initial consolidation step is used to achieve fully dense composites. Microstructures of boron-carbide-aluminum cermets have been produced with modulus of rupture exceeding 110 ksi and fracture toughness exceeding 12 ksi.sqroot.in. These composites and methods can be used to form a variety of structural elements.

  3. Single step synthesis of nanostructured boron nitride for boron neutron capture therapy

    SciTech Connect

    Singh, Bikramjeet; Singh, Paviter; Kumar, Akshay; Kumar, Manjeet; Thakur, Anup

    2015-05-15

    Nanostructured Boron Nitride (BN) has been successfully synthesized by carbo-thermic reduction of Boric Acid (H{sub 3}BO{sub 3}). This method is a relatively low temperature synthesis route and it can be used for large scale production of nanostructured BN. The synthesized nanoparticles have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and differential thermal analyzer (DTA). XRD analysis confirmed the formation of single phase nanostructured Boron Nitride. SEM analysis showed that the particles are spherical in shape. DTA analysis showed that the phase is stable upto 900 °C and the material can be used for high temperature applications as well boron neutron capture therapy (BNCT)

  4. Computational study of boron nitride nanotube synthesis: How catalyst morphology stabilizes the boron nitride bond

    NASA Astrophysics Data System (ADS)

    Riikonen, S.; Foster, A. S.; Krasheninnikov, A. V.; Nieminen, R. M.

    2009-10-01

    In an attempt to understand why catalytic methods for the growth of boron nitride nanotubes work much worse than for their carbon counterparts, we use first-principles calculations to study the energetics of elemental reactions forming N2 , B2 , and BN molecules on an iron catalyst. We observe that the local morphology of a step edge present in our nanoparticle model stabilizes the boron nitride molecule with respect to B2 due to the ability of the step edge to offer sites with different coordination simultaneously for nitrogen and boron. Our results emphasize the importance of atomic steps for a high yield chemical vapor deposition growth of BN nanotubes and may outline new directions for improving the efficiency of the method.

  5. ANALYSIS OF BORON DILUTION TRANSIENTS IN PWRS.

    SciTech Connect

    DIAMOND,D.J.BROMLEY,B.P.ARONSON,A.L.

    2004-02-04

    A study has been carried out with PARCS/RELAP5 to understand the consequences of hypothetical boron dilution events in pressurized water reactors. The scenarios of concern start with a small-break loss-of-coolant accident. If the event leads to boiling in the core and then the loss of natural circulation, a boron-free condensate can accumulate in the cold leg. The dilution event happens when natural circulation is re-established or a reactor coolant pump (RCP) is restarted in violation of operating procedures. This event is of particular concern in B&W reactors with a lowered-loop design and is a Generic Safety Issue for the U.S. Nuclear Regulatory Commission. The results of calculations with the reestablishment of natural circulation show that there is no unacceptable fuel damage. This is determined by calculating the maximum fuel pellet enthalpy, based on the three-dimensional model, and comparing it with the criterion for damage. The calculation is based on a model of a B&W reactor at beginning of the fuel cycle. If an RCP is restarted, unacceptable fuel damage may be possible in plants with sufficiently large volumes of boron-free condensate in the cold leg.

  6. Observation of an all-boron fullerene

    NASA Astrophysics Data System (ADS)

    Zhai, Hua-Jin; Zhao, Ya-Fan; Li, Wei-Li; Chen, Qiang; Bai, Hui; Hu, Han-Shi; Piazza, Zachary A.; Tian, Wen-Juan; Lu, Hai-Gang; Wu, Yan-Bo; Mu, Yue-Wen; Wei, Guang-Feng; Liu, Zhi-Pan; Li, Jun; Li, Si-Dian; Wang, Lai-Sheng

    2014-08-01

    After the discovery of fullerene-C60, it took almost two decades for the possibility of boron-based fullerene structures to be considered. So far, there has been no experimental evidence for these nanostructures, in spite of the progress made in theoretical investigations of their structure and bonding. Here we report the observation, by photoelectron spectroscopy, of an all-boron fullerene-like cage cluster at B40- with an extremely low electron-binding energy. Theoretical calculations show that this arises from a cage structure with a large energy gap, but that a quasi-planar isomer of B40- with two adjacent hexagonal holes is slightly more stable than the fullerene structure. In contrast, for neutral B40 the fullerene-like cage is calculated to be the most stable structure. The surface of the all-boron fullerene, bonded uniformly via delocalized σ and π bonds, is not perfectly smooth and exhibits unusual heptagonal faces, in contrast to C60 fullerene.

  7. Boron impregnation treatment of Eucalyptus grandis wood.

    PubMed

    Dhamodaran, T K; Gnanaharan, R

    2007-08-01

    Eucalyptus grandis is suitable for small timber purposes, but its wood is reported to be non-durable and difficult to treat. Boron compounds being diffusible, and the vacuum-pressure impregnation (VPI) method being more suitable for industrial-scale treatment, the possibility of boron impregnation of partially dry to green timber was investigated using a 6% boric acid equivalent (BAE) solution of boric acid and borax in the ratio 1:1.5 under different treatment schedules. It was found that E. grandis wood, even in green condition, could be pressure treated to desired chemical dry salt retention (DSR) and penetration levels using 6% BAE solution. Up to a thickness of 50mm, in order to achieve a DSR of 5 kg/m(3) boron compounds, the desired DSR level as per the Indian Standard for perishable timbers for indoor use, it was found that neither the moisture content of wood nor the treatment schedule posed any problem as far as the treatability of E. grandis wood was concerned.

  8. Synthesis of Sugar-Boronic Acid Derivatives: A Class of Potential Agents for Boron Neutron Capture Therapy.

    PubMed

    Imperio, Daniela; Del Grosso, Erika; Fallarini, Silvia; Lombardi, Grazia; Panza, Luigi

    2017-04-07

    To date, sugar analogues that contain boronic acids as substitutes for hydroxyl groups are a class of compounds nearly unknown in the literature. The challenging synthesis of two sugar-boronic acid analogues is described, and data are retrieved on their solution behavior, stability, and toxicity. As these compounds were expected to mimic the behavior of carbohydrates, they were tested in regards to their future development as potential boron neutron capture therapy agents.

  9. Towards new boron carriers for boron neutron capture therapy: metallacarboranes bearing cobalt, iron and chromium and their cholesterol conjugates.

    PubMed

    Białek-Pietras, Magdalena; Olejniczak, Agnieszka B; Tachikawa, Shoji; Nakamura, Hiroyuki; Leśnikowski, Zbigniew J

    2013-03-01

    A method for the synthesis of cholesterol-metallacarborane conjugates bearing cobalt, iron and chromium was developed. Effective incorporation of the cholesterol conjugate bearing cobalt into liposome membrane was revealed. Using the metallacarborane-encrusted liposomes as boron delivery system in vivo biodistribution experiments in tumor-bearing mice, high accumulation and selective delivery of boron into tumor tissues was observed. The results demonstrate that the cholesterol-metallacarborane conjugates can be considered as a potential candidate for boron delivery vehicle in BNCT.

  10. Pollution-free road lighting

    NASA Astrophysics Data System (ADS)

    Schreuder, Duco A.

    They relate to reducing road accidents and some forms of crime but also enhance the social safety of residents and pedestrians and the amenity for residents. Road traffic in developing countries is much more hazardous than in industrialized countries. Accident rates in 'low' income countries may be as much as 35 times higher than in 'high' income countries. Thus, it might be much more cost-effective to light roads in the developing world than in the industrialized world. Fighting light pollution is more pressing in developing countries as most of the major high-class astronomical observatories are there. Astronomical observations are disturbed by light from outdoor lighting installations, part of which is scattered in the atmosphere to form 'sky glow'. The International Lighting Commission CIE has published a Technical Report giving general guidance for lighting designers and policy makers on the reduction of the sky glow. Lighting improves visibility, essential for almost all human activity. However, light that hits the road contributes to visibility only if it is reflected. In poorly designed lighting equipment much of the lumen output of the lamps is sent directly upwards. This can be avoided by properly defined light fittings. The light output of fittings is determined by their optical quality and by the installation maintenance factor. Open fittings are to be preferred. If mounted horizontally, they make street lighting with the least light pollution.

  11. Traffic calming for the prevention of road traffic injuries: systematic review and meta-analysis

    PubMed Central

    Bunn, F; Collier, T; Frost, C; Ker, K; Roberts, I; Wentz, R

    2003-01-01

    Objective: To assess whether area-wide traffic calming schemes can reduce road crash related deaths and injuries. Design: Systematic review and meta-analysis. Data sources: Cochrane Injuries Group Specialised Register, Cochrane Central Register of Controlled Trials, Medline, EMBASE, Sociological Abstracts Science (and social science) citation index, National Technical Information service, Psychlit, Transport Research Information Service, International Road Research Documentation, and Transdoc, and web sites of road safety organisation were searched; experts were contacted, conference proceedings were handsearched, and relevant reference lists were checked. Inclusion criteria: Randomised controlled trials, and controlled before/after studies of area-wide traffic calming schemes designed to discourage and slow down through traffic on residential roads. Methods: Data were collected on road user deaths, injuries, and traffic crashes. For each study rate ratios were calculated, the ratio of event rates before and after intervention in the traffic calmed area divided by the corresponding ratio of event rates in the control area, which were pooled to give an overall estimate using a random effects model. Findings: Sixteen controlled before/after studies met our inclusion criteria. Eight studies reported the number of road user deaths: pooled rate ratio 0.63 (95% confidence interval (CI) 0.14 to 2.59). Sixteen studies reported the number of injuries (fatal and non-fatal): pooled rate ratio 0.89 (95% CI 0.80 to 1.00). All studies were in high income countries. Conclusion: Area-wide traffic calming in towns and cities has the potential to reduce road traffic injuries. However, further rigorous evaluations of this intervention are needed, especially in low and middle income countries. PMID:12966005

  12. Road-Traffic Noise: Annoyance, Risk Perception, and Noise Sensitivity in the Finnish Adult Population

    PubMed Central

    Okokon, Enembe Oku; Turunen, Anu W.; Ung-Lanki, Sari; Vartiainen, Anna-Kaisa; Tiittanen, Pekka; Lanki, Timo

    2015-01-01

    Exposure to road-traffic noise commonly engenders annoyance, the extent of which is determined by factors not fully understood. Our aim was to estimate the prevalence and determinants of road-traffic noise annoyance and noise sensitivity in the Finnish adult population, while comparing the perceptions of road-traffic noise to exhausts as environmental health problems. Using a questionnaire that yielded responses from 1112 randomly selected adult Finnish respondents, we estimated road-traffic noise- and exhausts-related perceived exposures, health-risk perceptions, and self-reported annoyance on five-point scales, while noise sensitivity estimates were based on four questions. Determinants of noise annoyance and sensitivity were investigated using multivariate binary logistic regression and linear regression models, respectively. High or extreme noise annoyance was reported by 17% of respondents. Noise sensitivity scores approximated a Gaussian distribution. Road-traffic noise and exhausts were, respectively, considered high or extreme population-health risks by 22% and 27% of respondents. Knowledge of health risks from traffic noise, OR: 2.04 (1.09–3.82) and noise sensitivity, OR: 1.07 (1.00–1.14) were positively associated with annoyance. Knowledge of health risks (p < 0.045) and positive environmental attitudes (p < 000) were associated with higher noise sensitivity. Age and sex were associated with annoyance and sensitivity only in bivariate models. A considerable proportion of Finnish adults are highly annoyed by road-traffic noise, and perceive it to be a significant health risk, almost comparable to traffic exhausts. There is no distinct noise-sensitive population subgroup. Knowledge of health risks of road-traffic noise, and attitudinal variables are associated with noise annoyance and sensitivity. PMID:26016432

  13. 49 CFR 391.31 - Road test.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 5 2011-10-01 2011-10-01 false Road test. 391.31 Section 391.31 Transportation... COMBINATION VEHICLE (LCV) DRIVER INSTRUCTORS Tests § 391.31 Road test. (a) Except as provided in subpart G, a... test and has been issued a certificate of driver's road test in accordance with this section. (b)...

  14. HOW FAR TO THE NEAREST ROAD?

    EPA Science Inventory

    Increases in impervious surface area lead to declines in chemical and biological indicators of water quality .Roads are an important aspect of impervious surface, and distance to roads is an indicator of the potential threat to aquatic and terrestrial ecosystems. Although roads a...

  15. Image feature based GPS trace filtering for road network generation and road segmentation

    DOE PAGES

    Yuan, Jiangye; Cheriyadat, Anil M.

    2015-10-19

    We propose a new method to infer road networks from GPS trace data and accurately segment road regions in high-resolution aerial images. Unlike previous efforts that rely on GPS traces alone, we exploit image features to infer road networks from noisy trace data. The inferred road network is used to guide road segmentation. We show that the number of image segments spanned by the traces and the trace orientation validated with image features are important attributes for identifying GPS traces on road regions. Based on filtered traces , we construct road networks and integrate them with image features to segmentmore » road regions. Lastly, our experiments show that the proposed method produces more accurate road networks than the leading method that uses GPS traces alone, and also achieves high accuracy in segmenting road regions even with very noisy GPS data.« less

  16. Image feature based GPS trace filtering for road network generation and road segmentation

    SciTech Connect

    Yuan, Jiangye; Cheriyadat, Anil M.

    2015-10-19

    We propose a new method to infer road networks from GPS trace data and accurately segment road regions in high-resolution aerial images. Unlike previous efforts that rely on GPS traces alone, we exploit image features to infer road networks from noisy trace data. The inferred road network is used to guide road segmentation. We show that the number of image segments spanned by the traces and the trace orientation validated with image features are important attributes for identifying GPS traces on road regions. Based on filtered traces , we construct road networks and integrate them with image features to segment road regions. Lastly, our experiments show that the proposed method produces more accurate road networks than the leading method that uses GPS traces alone, and also achieves high accuracy in segmenting road regions even with very noisy GPS data.

  17. 46 CFR 56.01-3 - Power boilers, external piping and appurtenances (Replaces 100.1.1, 100.1.2, 122.1, 132 and 133).

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Power boilers, external piping and appurtenances... boilers, external piping and appurtenances (Replaces 100.1.1, 100.1.2, 122.1, 132 and 133). (a) Power boiler external piping and components must meet the requirements of this part and §§ 52.01-105,...

  18. 46 CFR 56.01-3 - Power boilers, external piping and appurtenances (Replaces 100.1.1, 100.1.2, 122.1, 132 and 133).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Power boilers, external piping and appurtenances... boilers, external piping and appurtenances (Replaces 100.1.1, 100.1.2, 122.1, 132 and 133). (a) Power boiler external piping and components must meet the requirements of this part and §§ 52.01-105,...

  19. 46 CFR 56.01-3 - Power boilers, external piping and appurtenances (Replaces 100.1.1, 100.1.2, 122.1, 132 and 133).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Power boilers, external piping and appurtenances... boilers, external piping and appurtenances (Replaces 100.1.1, 100.1.2, 122.1, 132 and 133). (a) Power boiler external piping and components must meet the requirements of this part and §§ 52.01-105,...

  20. 46 CFR 56.01-3 - Power boilers, external piping and appurtenances (Replaces 100.1.1, 100.1.2, 122.1, 132 and 133).

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Power boilers, external piping and appurtenances... boilers, external piping and appurtenances (Replaces 100.1.1, 100.1.2, 122.1, 132 and 133). (a) Power boiler external piping and components must meet the requirements of this part and §§ 52.01-105,...

  1. 46 CFR 56.01-3 - Power boilers, external piping and appurtenances (Replaces 100.1.1, 100.1.2, 122.1, 132 and 133).

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Power boilers, external piping and appurtenances... boilers, external piping and appurtenances (Replaces 100.1.1, 100.1.2, 122.1, 132 and 133). (a) Power boiler external piping and components must meet the requirements of this part and §§ 52.01-105,...

  2. Formation of boron nitride and boron carbide composite by nitrogen implantation at elevated temperature

    NASA Astrophysics Data System (ADS)

    Yu, N.; Romero-Borja, F.; Zhang, Z. H.; Cui, X. T.; Liu, J. R.; Wood, L. T.; Chu, W. K.; Marton, D.; Rabalais, J. W.; Forster, K. M.; Reeber, R. R.

    1993-09-01

    Boron carbide (B4C) is a wear resistant material with hardness slightly less than that of diamond. It has an excellent strength to weight ratio and relatively high toughness under controlled processing. These essential mechanical properties make B4C an ideal candidate for cutting tool and bearing applications. We will demonstrate that hexagonal boron nitride (h-BN), a good solid lubricant, can be formed on B4C surfaces through high temperature (850 °C) nitrogen ion implantation. The formation of composite B4C and h-BN on the B4C surface can potentially reduce surface friction coefficients, making the material more attractive for tribological applications.

  3. Road Traffic Accidents in Kazakhstan

    PubMed Central

    AUBAKIROVA, Alma; KOSSUMOV, Alibek; IGISSINOV, Nurbek

    2013-01-01

    Background: The article provides the analysis of death rates in road traffic accidents in Kazakhstan from 2004 to 2010 and explores the use of sanitary aviation. Methods: Data of fatalities caused by road traffic accidents were collected and analysed. Descriptive and analytical methods of epidemiology and biomedical statistics were applied. Results: Totaly 27,003 people died as a result of road traffic accidents in this period. The death rate for the total population due to road traffic accidents was 25.0±2.10/0000. The death rate for men was (38.3±3.20/0000), which was higher (P<0.05) than that for women (12.6±1.10/0000). High death rates in the entire male population were identified among men of 30–39 years old, whereas the highest rates for women were attributed to the groups of 50–59 years old and 70–79 years old. In time dynamics, death rates tended to decrease: the total population (Tdec=−2.4%), men (Tdec=−2.3%) and women (Tdec=−1.4%). When researching territorial relevance, the rates were established as low (to 18.30/0000), average (between 18.3 and 24.00/0000) and high (from 24.00/0000 and above). Thus, the regions with high rates included Akmola region (24.30/0000), Mangistau region (25.90/0000), Zhambyl region (27.30/0000), Almaty region (29.30/0000) and South Kazakhstan region (32.40/0000). Conclusion: The identified epidemiological characteristics of the population deaths rates from road traffic accidents should be used in integrated and targeted interventions to enhance prevention of injuries in accidents. PMID:23641400

  4. Perception of road accident causes.

    PubMed

    Vanlaar, Ward; Yannis, George

    2006-01-01

    A theoretical two-dimensional model on prevalence and risk was developed. The objective of this study was to validate this model empirically to answer three questions: How do European drivers perceive the importance of several causes of road accidents? Are there important differences in perceptions between member states? Do these perceptions reflect the real significance of road accident causes? Data were collected from 23 countries, based on representative national samples of at least 1000 respondents each (n=24,372). Face-to-face interviews with fully licensed, active car drivers were conducted using a questionnaire containing closed answer questions. Respondents were asked to rate 15 causes of road accidents, each using a six-point ordinal scale. The answers were analyzed by calculating Kendall's tau for each pair of items to form lower triangle similarity matrices per country and for Europe as a whole. These matrices were then used as the input files for an individual difference scaling to draw a perceptual map of the 15 items involved. The hypothesized model on risk and prevalence fits the data well and enabled us to answer the three questions of concern. The subject space of the model showed that there are no relevant differences between the 23 countries. The group space of the model comprises four quadrants, each containing several items (high perceived risk/low perceived prevalence items; high perceived risk/high perceived prevalence items; low perceived risk/high perceived prevalence items and low perceived risk/low perceived prevalence items). Finally, perceptions of the items driving under the influence of alcohol, drugs and medicines and driving using a handheld or hands-free mobile phone are discussed with regard to their real significance in causing road accidents. To conclude, individual difference scaling offers some promising possibilities to study drivers' perception of road accident causes.

  5. 2. VIEW OF SWITCHBACKS IN FORESTA ROAD (OLD DAVIS CUTOFF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. VIEW OF SWITCHBACKS IN FORESTA ROAD (OLD DAVIS CUT-OFF ROAD). NOTE FORESTA ROAD BRIDGE IN LOWER LEFT. ROAD CURVE HIDDEN IN TREES AT CENTER. NOTE ROAD CUT AT LEFT. LOOKING SSW. GIS: N-37"40'47.4"/W-119"47'22.2 - Foresta Road, Yosemite Village, Mariposa County, CA

  6. Chemical disposition of boron in animals and humans.

    PubMed Central

    Moseman, R F

    1994-01-01

    Elemental boron was isolated in 1808. It typically occurs in nature as borates hydrated with varying amounts of water. Important compounds are boric acid and borax. Boron compounds are also used in the production of metals, enamels, and glasses. In trace amounts, boron is essential for the growth of many plants, and is found in animal and human tissues at low concentrations. Poisoning in humans has been reported as the result of accidental ingestion or use of large amounts in the treatment of burns. Boron as boric acid is fairly rapidly absorbed and excreted from the body via urine. The half-life of boric acid in humans is on the order of 1 day. Boron does not appear to accumulate in soft tissues of animals, but does accumulate in bone. Normal levels of boron in soft tissues, urine, and blood generally range from less than 0.05 ppm to no more than 10 ppm. In poisoning incidents, the amount of boric acid in brain and liver tissue has been reported to be as high as 2000 ppm. Recent studies at the National Institute of Environmental Health Sciences have indicated that boron may contribute to reduced fertility in male rodents fed 9000 ppm of boric acid in feed. Within a few days, boron levels in blood and most soft tissues quickly reached a plateau of about 15 ppm. Boron in bone did not appear to plateau, reaching 47 ppm after 7 days on the diet. Cessation of exposure to dietary boron resulted in a rapid drop in bone boron.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7889870

  7. Roles of ATR1 paralogs YMR279c and YOR378w in boron stress tolerance.

    PubMed

    Bozdag, Gonensin Ozan; Uluisik, Irem; Gulculer, Gulce Sila; Karakaya, Huseyin C; Koc, Ahmet

    2011-06-17

    Boron is a necessary nutrient for plants and animals, however excess of it causes toxicity. Previously, Atr1 and Arabidopsis Bor1 homolog were identified as the boron efflux pump in yeast, which lower the cytosolic boron concentration and help cells to survive in the presence of toxic amount of boron. In this study, we analyzed ATR1 paralogs, YMR279c and YOR378w, to understand whether they participate in boron stress tolerance in yeast. Even though these genes share homology with ATR1, neither their deletion rendered cells boron sensitive nor their expression was significantly upregulated by boron treatment. However, expression of YMR279, but not YOR378w, from the constitutive GAPDH promoter on a high copy plasmid provided remarkable boron resistance by decreasing intracellular boron levels. Thus our results suggest the presence of a third boron exporter, YMR279c, which functions similar to ATR1 and provides boron resistance in yeast.

  8. Road Safety Barriers, the Need and Influence on Road Traffic Accidents

    NASA Astrophysics Data System (ADS)

    Butāns, Ž.; Gross, K. A.; Gridnevs, A.; Karzubova, E.

    2015-11-01

    Constantly increasing intensity of road traffic and the allowed speed limits seem to impose stronger requirements on road infrastructure and use of road safety systems. One of the ways to improve road safety is the use of road restraint systems. Road safety barriers allow not only reducing the number of road traffic accidents, but also lowering the severity of accidents. The paper provides information on the technical requirements of road safety barriers. Various types of road safety barriers and their selection criteria for different types of road sections are discussed. The article views an example of a road traffic accident, which is also modelled by PC-Crash computer program. The given example reflects a road accident mechanism in case of a car-to-barrier collision, and provides information about the typical damage to the car and the barrier. The paper describes an impact of the road safety barrier type and its presence on the road traffic accident mechanism. Implementation and maintenance costs of different barrier types are viewed. The article presents a discussion on the necessity to use road safety barriers, as well as their optimal choice.

  9. Measuring Road Network Vulnerability with Sensitivity Analysis

    PubMed Central

    Jun-qiang, Leng; Long-hai, Yang; Liu, Wei-yi; Zhao, Lin

    2017-01-01

    This paper focuses on the development of a method for road network vulnerability analysis, from the perspective of capacity degradation, which seeks to identify the critical infrastructures in the road network and the operational performance of the whole traffic system. This research involves defining the traffic utility index and modeling vulnerability of road segment, route, OD (Origin Destination) pair and road network. Meanwhile, sensitivity analysis method is utilized to calculate the change of traffic utility index due to capacity degradation. This method, compared to traditional traffic assignment, can improve calculation efficiency and make the application of vulnerability analysis to large actual road network possible. Finally, all the above models and calculation method is applied to actual road network evaluation to verify its efficiency and utility. This approach can be used as a decision-supporting tool for evaluating the performance of road network and identifying critical infrastructures in transportation planning and management, especially in the resource allocation for mitigation and recovery. PMID:28125706

  10. BORON NITRIDE CAPACITORS FOR ADVANCED POWER ELECTRONIC DEVICES

    SciTech Connect

    N. Badi; D. Starikov; C. Boney; A. Bensaoula; D. Johnstone

    2010-11-01

    This project fabricates long-life boron nitride/boron oxynitride thin film -based capacitors for advanced SiC power electronics with a broad operating temperature range using a physical vapor deposition (PVD) technique. The use of vapor deposition provides for precise control and quality material formation.

  11. Predicted phase diagram of boron-carbon-nitrogen

    NASA Astrophysics Data System (ADS)

    Zhang, Hantao; Yao, Sanxi; Widom, Michael

    2016-04-01

    Noting the structural relationships between phases of carbon and boron carbide with phases of boron nitride and boron subnitride, we investigate their mutual solubilities using a combination of first-principles total energies supplemented with statistical mechanics to address finite temperatures. Thus we predict the solid-state phase diagram of boron-carbon-nitrogen (B-C-N). Owing to the large energy costs of substitution, we find that the mutual solubilities of the ultrahard materials diamond and cubic boron nitride are negligible, and the same for the quasi-two-dimensional materials graphite and hexagonal boron nitride. In contrast, we find a continuous range of solubility connecting boron carbide to boron subnitride at elevated temperatures. An electron-precise ternary compound B13CN consisting of B12 icosahedra with NBC chains is found to be stable at all temperatures up to melting. It exhibits an order-disorder transition in the orientation of NBC chains at approximately T =500 K. We also propose that the recently discovered binary B13N2 actually has composition B12.67N2 .

  12. Boron containing amino acid compounds and methods for their use

    DOEpatents

    Glass, John D.; Coderre, Jeffrey A.

    2000-01-01

    The present invention provides new boron containing amino acid compounds and methods for making these compounds by contacting melphalan or another nitrogen mustard derivative and sodium borocaptate. The present invention also provides a method of treating a mammal having a tumor by administering to the mammal a therapeutically effective amount of the new boron containing amino acid compounds.

  13. Determination of boron in silicates after ion exchange separation

    USGS Publications Warehouse

    Kramer, H.

    1955-01-01

    Existing methods for the determination of boron in silicates are not entirely satisfactory. Separation as the methyl ester is lengthy and frequently erratic. An accurate and rapid method applicable to glass, mineral, ore, and water samples uses ion exchange to remove interfering cations, and boron is determined titrimetrically in the presence of mannitol, using a pH meter to indicate the end point.

  14. Boron containing amino acid compounds and methods for their use

    SciTech Connect

    Glass, J.D.; Coderre, J.A.

    2000-01-25

    The present invention provides new boron containing amino acid compounds and methods for making these compounds by contacting melphalan or another nitrogen mustard derivative and sodium borocaptate. The present invention also provides a method of treating a mammal having a tumor by administering to the mammal a therapeutically effective amount of the new boron containing amino acid compounds.

  15. Effect of boron on carbon-fiber microstructure and reactivity

    SciTech Connect

    Jones, L.E.

    1987-01-01

    A mesophase pitch P55 and a PAN T-300 carbon filter were substitutionally doped with boron at concentration levels ranging from 4 x 10/sup -5/ to 0.05 B/C atom ratio. Boron enhanced graphitization in these fibers at concentrations greater than 2 x 10/sup -4/ B/C. Below this concentration level, the microstructure of the pitch P55 fiber was unaffected. High concentrations of boron were found to modulate the (001) diffraction profiles in both fibers. This indicated the presence of two separate graphite fractions in the same fiber (one fraction was much more turbostratic than the other). The presence of boron was also found to increase the L/sub c/ and decrease the L/sub a/ dimensions of the more graphitic fractions of the fiber structure. The decrease in the L/sub a/ is the result of an increase in tilt boundaries along the a direction, parallel to the fiber axis. The presence of boron inhibits fiber gasification. The cause of gasification inhibition at high boron concentrations is related to changes in the fiber microstructure; however, there is a pronounced effect of specific-site blockage by an oxide of boron that develops on the surface during gasification. At relatively low boron concentrations, decrease in the reactivity of the fiber was correlated to changes in fiber electronic structure which, in turn, influences the chemistry of the active surface sites.

  16. Low-dimensional boron structures based on icosahedron B12

    NASA Astrophysics Data System (ADS)

    Kah, C. B.; Yu, M.; Tandy, P.; Jayanthi, C. S.; Wu, S. Y.

    2015-10-01

    One-dimensional icosahedral boron chains and two-dimensional icosahedral boron sheets (icosahedral α, δ6, and δ4 sheets) that contain icosahedra B12 as their building units have been predicted in a computer simulation study using a state-of-the-art semi-empirical Hamiltonian. These novel low-dimensional icosahedral structures exhibit interesting bonding and electronic properties. Specifically, the three-center, two-electron bonding between icosahedra B12 of the boron bulk (rhombohedral boron) transforms into a two-center bonding in these new allotropes of boron sheets. In contrast to the previously reported stable buckled α and triangular boron monolayer sheets, these new allotropes of boron sheets form a planar network. Calculations of electronic density of states (DOS) reveal a semiconducting nature for both the icosahedral chain and the icosahedral δ6 and δ4 sheets, as well as a nearly gapless (or metallic-like) feature in the DOS for the icosahedral α sheet. The results for the energy barrier per atom between the icosahedral δ6 and α sheets (0.17 eV), the icosahedral δ6 and δ4 sheets (0.38 eV), and the icosahedral α and δ4 sheets (0.27 eV), as indicated in the respective parentheses, suggest that these new allotropes of boron sheets are relatively stable.

  17. Predicting Boron, Molybdenum, Selenium, and Arsenic Adsorption in Soil Systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A chemical surface complexation model was applied to boron, molybdenum, selenium, and arsenic adsorption on up to 49 soils selected for variation in soil properties. The surface complexation model was able to fit boron, molybdenum, selenite, and arsenate adsorption on the soils. General regression...

  18. Boron diffusion across the dialysis membrane during hemodialysis.

    PubMed

    Usuda, K; Kono, K; Nishiura, K; Miyata, K; Nishiura, H; Saito, M; Goto, E; Nakaya, H

    1997-01-01

    To investigate the movement of boron across the dialysis membrane, serum and dialysate boron levels of long-term hemodialysis (HD) patients (n = 17) were determined using inductively coupled plasma emission spectrometry in both the inlet and the outlet side of the dialyzer. Results revealed that 77.8% of the serum boron in the inlet side of the dialyzer was filterable and 94.4% of filterable boron was actually filtered during HD. Boron dialysance was found to be 138.6 +/- 16.1 ml/min, and this value was higher than the clearance value of blood urea nitrogen (not significant), phosphorus and creatinine (p < 0.001). It is concluded that HD is effective in eliminating serum boron even at low concentrations, and boron can be classified as an element that is easily diffusible across the dialysis membrane. There seems to be relatively little relation of boron to serum constituents of macromolecules that are reported to have a major impact on the diffusion of trace elements across the HD membrane.

  19. Method for removal of phosgene from boron trichloride

    DOEpatents

    Freund, S.M.

    1983-09-20

    Selective ultraviolet photolysis using an unfiltered mercury arc lamp has been used to substantially reduce the phosgene impurity in a mixture of boron trichloride and phosgene. Infrared spectrophotometric analysis of the sample before and after irradiation shows that it is possible to highly purify commercially available boron trichloride with this method. 5 figs.

  20. Method for removal of phosgene from boron trichloride

    DOEpatents

    Freund, Samuel M.

    1983-01-01

    Selective ultraviolet photolysis using an unfiltered mercury arc lamp has been used to substantially reduce the phosgene impurity in a mixture of boron trichloride and phosgene. Infrared spectrophotometric analysis of the sample before and after irradiation shows that is is possible to highly purify commercially available boron trichloride with this method.

  1. Growing evidence for human health benefits of boron

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Growing evidence from numerous laboratories using a variety of experimental models shows that boron is a bioactive beneficial, perhaps essential, element for humans. Reported beneficial actions of boron include arthritis alleviation or risk reduction; bone growth and maintenance; central nervous sys...

  2. RADIATION PROTECTION THROUGH BORON-CONTAINING CEMENTS AND CONCRETES

    DTIC Science & Technology

    WATER-SOLUBLE BORON COMPOUNDS, SUCH AS BORIC ACID OR BORAX , RETARDS THE SETTING OF CEMENT AND IMPAIRS THE MECHANICAL STRENGTH OF CONCRETE. The...deterioration was found to depend on the quantity of boron introduced, regardless of whether it is in the acid form ( boric acid ) or the alkaline form ( borax

  3. Boron diffusion in nanocrystalline 3C-SiC

    SciTech Connect

    Schnabel, Manuel; Weiss, Charlotte; Rachow, Thomas; Löper, Philipp; Janz, Stefan; Canino, Mariaconcetta; Summonte, Caterina; Mirabella, Salvo; Wilshaw, Peter R.

    2014-05-26

    The diffusion of boron in nanocrystalline silicon carbide (nc-SiC) films with a grain size of 4–7 nm is studied using a poly-Si boron source. Diffusion is found to be much faster than in monocrystalline SiC as it takes place within the grain boundary (GB) network. Drive-in temperatures of 900–1000°C are suitable for creating shallow boron profiles up to 100 nm deep, while 1100°C is sufficient to flood the 200 nm thick films with boron. From the resulting plateau at 1100 °C a boron segregation coefficient of 28 between nc-SiC and the Si substrate, as well as a GB boron solubility limit of 0.2 nm{sup −2} is determined. GB diffusion in the bulk of the films is Fickian and thermally activated with D{sub GB}(T)=(3.1−5.6)×10{sup 7}exp(−5.03±0.16  eV/k{sub B}T) cm{sup 2}s{sup −1}. The activation energy is interpreted in terms of a trapping mechanism at dangling bonds. Higher boron concentrations are present at the nc-SiC surface and are attributed to immobilized boron.

  4. Boron as a tracer of aerosol from combustion of coal

    NASA Astrophysics Data System (ADS)

    Fogg, Thomas R.; Rahn, Kenneth A.

    1984-09-01

    Atmospheric boron was found to be predominantly gaseous in ambient samples and in stacks of coal-fired power plants. Typical gas/particulate ratios ranged from 20 to more than 100, with stack ratios above 100 and ambient ratios generally below 100. In the stacks, B/SO2 ratios were lower than expected from bulk U.S. coals, consistent with volatilization of 20-80 percent of the boron during combustion. Midwestern ambient B/SO2 ratios were at or above stack values, with the lowest ratios associated with highest concentrations. SO2 was always more variable than gaseous boron. These observations are consistent with coal combustion as the major source of atmospheric boron (and SO2) in the Midwest. In northern Vermont, concentrations of gaseous boron and SO2 were several times lower than in the Midwest, but the B/SO2 ratio was several times higher. Both species passed through quasiweekly in-phase cycles of concentration with the relative amplitudes being greater for SO2 than for gaseous boron. All major pulses of boron and SO2 came from the direction of the Midwest, on the backsides of high-pressure areas. Since the ocean is also a source of gaseous boron, its anthropogenic tracer potential for acid deposition studies will be most useful in the interior of continents.

  5. Modelling boron-lined proportional counter response to neutrons.

    PubMed

    Shahri, A; Ghal-Eh, N; Etaati, G R

    2013-09-01

    The detailed Monte Carlo simulation of a boron-lined proportional counter response to a neutron source has been presented. The MCNP4C and experimental data on different source-moderator geometries have been given for comparison. The influence of different irradiation geometries and boron-lining thicknesses on the detector response has been studied.

  6. The loss of boron in ultra-shallow boron implanted Si under heavy ion irradiation

    NASA Astrophysics Data System (ADS)

    Pelicon, P.; El Bouanani, M.; Prasad, G. V. R.; Razpet, A.; Simcic, J.; Guo, B. N.; Birt, D.; Duggan, J. L.; McDaniel, F. D.

    2006-08-01

    Heavy ion impact has been known to cause a loss of light elements from the near-surface region of the irradiated sample. One of the possible approaches to a better understanding of the processes responsible for the release of specific elements is to irradiate shallow-implanted samples, which exhibit a well-known depth distribution of the implanted species. In this work, the samples studied were produced by implantation of Si wafers with 11 B at implantation energies of 250 and 500 eV and fluence of 1.0x10(15) atoms/cm 2 . Elastic Recoil Detection Analysis was applied to monitor the remnant boron fluence in the sample. Irradiation of the samples by a 14.2 (MeVF4+)-F-19 beam resulted in a slow decrease of boron remnant fluence with initial loss rates of the order of 0.05 B atom per impact ion. Under irradiation with 12 (MeVS3+)-S-32 ions, the remnant boron fluence in Si decreased exponentially with a much faster loss rate of boron and became constant after a certain heavy ion irradiation dose. A simple model, which assumes a finite desorption range and corresponding depletion of the near-surface region, was used to describe the observations. The depletion depths under the given irradiation conditions were calculated from the measured data.

  7. Isotopic Enrichment of Boron in the Sputtering of Boron Nitride with Xenon Ions

    NASA Technical Reports Server (NTRS)

    Ray, P. K.; Shutthanandan, V.

    1998-01-01

    An experimental study is described to measure the isotopic enrichment of boron. Xenon ions from 100 eV to 1.5 keV were used to sputter a boron nitride target. An ion gun was used to generate the ion beam. The ion current density at the target surface was approximately 30 microA/sq cm. Xenon ions impinged on the target surface at 50 deg angle to the surface normal. Since boron nitride is an insulator, a flood electron gun was used in our experiments to neutralize the positive charge buildup on the target surface. The sputtered secondary ions of boron were detected by a quadrupole mass spectrometer. The spectrometer entrance aperture was located perpendicular to the ion beam direction and 10 mm away from the target surface. The secondary ion flux was observed to be enriched in the heavy isotopes at lower ion energies. The proportion of heavy isotopes in the sputtered secondary ion flux was found to decrease with increasing primary ion energy from 100 to 350 eV. Beyond 350 eV, light isotopes were sputtered preferentially. The light isotope enrichment factor was observed to reach an asymptotic value of 1.27 at 1.5 keV. This trend is similar to that of the isotopic enrichment observed earlier when copper was sputtered with xenon ions in the same energy range.

  8. Boron distribution and the effect of lime on boron uptake by pansy, petunia, and gerbera plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Reports of boron (B) deficiency have become more prevalent in pansy (Viola ×wittrockiana), petunia (Petunia ×hybrida), and gerbera (Gerbera jamesonii) plug production. When symptoms are observed in production the presence and severity of symptoms have no pattern, symptomatic plants can be located a...

  9. Boron-based nanostructures: Synthesis, functionalization, and characterization

    NASA Astrophysics Data System (ADS)

    Bedasso, Eyrusalam Kifyalew

    Boron-based nanostructures have not been explored in detail; however, these structures have the potential to revolutionize many fields including electronics and biomedicine. The research discussed in this dissertation focuses on synthesis, functionalization, and characterization of boron-based zero-dimensional nanostructures (core/shell and nanoparticles) and one-dimensional nanostructures (nanorods). The first project investigates the synthesis and functionalization of boron-based core/shell nanoparticles. Two boron-containing core/shell nanoparticles, namely boron/iron oxide and boron/silica, were synthesized. Initially, boron nanoparticles with a diameter between 10-100 nm were prepared by decomposition of nido-decaborane (B10H14) followed by formation of a core/shell structure. The core/shell structures were prepared using the appropriate precursor, iron source and silica source, for the shell in the presence of boron nanoparticles. The formation of core/shell nanostructures was confirmed using high resolution TEM. Then, the core/shell nanoparticles underwent a surface modification. Boron/iron oxide core/shell nanoparticles were functionalized with oleic acid, citric acid, amine-terminated polyethylene glycol, folic acid, and dopamine, and boron/silica core/shell nanoparticles were modified with 3-(amino propyl) triethoxy silane, 3-(2-aminoethyleamino)propyltrimethoxysilane), citric acid, folic acid, amine-terminated polyethylene glycol, and O-(2-Carboxyethyl)polyethylene glycol. A UV-Vis and ATR-FTIR analysis established the success of surface modification. The cytotoxicity of water-soluble core/shell nanoparticles was studied in triple negative breast cancer cell line MDA-MB-231 and the result showed the compounds are not toxic. The second project highlights optimization of reaction conditions for the synthesis of boron nanorods. This synthesis, done via reduction of boron oxide with molten lithium, was studied to produce boron nanorods without any

  10. The Road Traffic Injuries Research Network: a decade of research capacity strengthening in low- and middle-income countries.

    PubMed

    Hyder, Adnan A; Norton, Robyn; Pérez-Núñez, Ricardo; Mojarro-Iñiguez, Francisco R; Peden, Margie; Kobusingye, Olive

    2016-02-27

    Road traffic crashes have been an increasing threat to the wellbeing of road users worldwide; an unacceptably high number of people die or become disabled from them. While high-income countries have successfully implemented effective interventions to help reduce the burden of road traffic injuries (RTIs) in their countries, low- and middle-income countries (LMICs) have not yet achieved similar results. Both scientific research and capacity development have proven to be useful for preventing RTIs in high-income countries. In 1999, a group of leading researchers from different countries decided to join efforts to help promote research on RTIs and develop the capacity of professionals from LMICs. This translated into the creation of the Road Traffic Injuries Research Network (RTIRN) - a partnership of over 1,100 road safety professionals from 114 countries collaborating to facilitate reductions in the burden of RTIs in LMICs by identifying and promoting effective, evidenced-based interventions and supporting research capacity building in road safety research in LMICs. This article presents the work that RTIRN has done over more than a decade, including production of a dozen scientific papers, support of nearly 100 researchers, training of nearly 1,000 people and 35 scholarships granted to researchers from LMICs to attend world conferences, as well as lessons learnt and future challenges to maximize its work.

  11. A computational study of carbon dioxide adsorption on solid boron.

    PubMed

    Sun, Qiao; Wang, Meng; Li, Zhen; Du, Aijun; Searles, Debra J

    2014-07-07

    Capturing and sequestering carbon dioxide (CO2) can provide a route to partial mitigation of climate change associated with anthropogenic CO2 emissions. Here we report a comprehensive theoretical study of CO2 adsorption on two phases of boron, α-B12 and γ-B28. The theoretical results demonstrate that the electron deficient boron materials, such as α-B12 and γ-B28, can bond strongly with CO2 due to Lewis acid-base interactions because the electron density is higher on their surfaces. In order to evaluate the capacity of these boron materials for CO2 capture, we also performed calculations with various degrees of CO2 coverage. The computational results indicate CO2 capture on the boron phases is a kinetically and thermodynamically feasible process, and therefore from this perspective these boron materials are predicted to be good candidates for CO2 capture.

  12. Advancements in Tumor Targeting Strategies for Boron Neutron Capture Therapy.

    PubMed

    Luderer, Micah John; de la Puente, Pilar; Azab, Abdel Kareem

    2015-09-01

    Boron neutron capture therapy (BNCT) is a promising cancer therapy modality that utilizes the nuclear capture reaction of epithermal neutrons by boron-10 resulting in a localized nuclear fission reaction and subsequent cell death. Since cellular destruction is limited to approximately the diameter of a single cell, primarily only cells in the neutron field with significant boron accumulation will be damaged. However, the emergence of BNCT as a prominent therapy has in large part been hindered by a paucity of tumor selective boron containing agents. While L-boronophenylalanine and sodium borocaptate are the most commonly investigated clinical agents, new agents are desperately needed due to their suboptimal tumor selectivity. This review will highlight the various strategies to improve tumor boron delivery including: nucleoside and carbohydrate analogs, unnatural amino acids, porphyrins, antibody-dendrimer conjugates, cationic polymers, cell-membrane penetrating peptides, liposomes and nanoparticles.

  13. Elemental Boron for Efficient Carbon Dioxide Reduction under Light Irradiation.

    PubMed

    Liu, Guigao; Meng, Xianguang; Zhang, Huabin; Zhao, Guixia; Pang, Hong; Wang, Tao; Li, Peng; Kako, Tetsuya; Ye, Jinhua

    2017-03-24

    The photoreduction of CO2 is attractive for the production of renewable fuels and the mitigation of global warming. Herein, we report an efficient method for CO2 reduction over elemental boron catalysts in the presence of only water and light irradiation through a photothermocatalytic process. Owing to its high solar-light absorption and effective photothermal conversion, the illuminated boron catalyst experiences remarkable self-heating. This process favors CO2 activation and also induces localized boron hydrolysis to in situ produce H2 as an active proton source and electron donor for CO2 reduction as well as boron oxides as promoters of CO2 adsorption. These synergistic effects, in combination with the unique catalytic properties of boron, are proposed to account for the efficiency of the CO2 reduction. This study highlights the promise of photothermocatalytic strategies for CO2 conversion and also opens new avenues towards the development of related solar-energy utilization schemes.

  14. Elastic properties of various boron-nitride structures

    NASA Astrophysics Data System (ADS)

    Oh, Eun-Suok

    2011-02-01

    The stress-deformation behaviors derived from the continuum-lattice thermodynamic approach were applied to estimate the elastic properties of various boron-nitride crystals, such as boron-nitride sheets and nanotubes as well as cubic boron-nitride. The Tersoff and Tersoff-like potentials were used to describe the interatomic bond potential for the boron-nitride crystals. In this study, three sets of the Tersoff potential parameters and two sets of the Tersoff-like potential parameters from the literature were employed. Both the Tersoff potential parameters proposed by Matsunaga et al. and the Tersoff-like potential parameters proposed by Oh were best for estimating the elastic properties of boron-nitride nanotubes, including a sheet. Meanwhile, the elastic constants of c-BN calculated by the Tersoff potential parameters proposed by Sekkal et al. and the Tersofflike potential parameters proposed by Albe and Moller were in good agreement with experimental and other quantumistic calculation results.

  15. Safety Assessment of Boron Nitride as Used in Cosmetics.

    PubMed

    Fiume, Monice M; Bergfeld, Wilma F; Belsito, Donald V; Hill, Ronald A; Klaassen, Curtis D; Liebler, Daniel C; Marks, James G; Shank, Ronald C; Slaga, Thomas J; Snyder, Paul W; Andersen, F Alan

    2015-01-01

    The Cosmetic Ingredient Review Expert Panel (Panel) assessed the safety of boron nitride which functions in cosmetics as a slip modifier (ie, it has a lubricating effect). Boron nitride is an inorganic compound with a crystalline form that can be hexagonal, spherical, or cubic; the hexagonal form is presumed to be used in cosmetics. The highest reported concentration of use of boron nitride is 25% in eye shadow formulations. Although boron nitride nanotubes are produced, boron nitride is not listed as a nanomaterial used in cosmetic formulations. The Panel reviewed available chemistry, animal data, and clinical data and concluded that this ingredient is safe in the present practices of use and concentration in cosmetic formulations.

  16. Quarry Haul Road Ecological Survey

    SciTech Connect

    Not Available

    1992-09-01

    This biological survey was performed to document the summer flora and fauna found along the haul road constructed as part of the remedial action for the quarry bulk waste. State and Federal species listed as threatened or endangered were noted if encountered while surveying. Sampling locations were equally spaced along the quarry haul road, and a survey for vegetation and birds conducted at each location. Bird observations were conducted as breeding bird surveys once in June of 1991, and again in June of 1992. Each year's survey includes two observations in the early morning and one late in the evening. Vegetation surveys were conducted in 1991 using quadrants and transects. mammal, reptile, and amphibian sightings were noted as encountered.

  17. Roads, railways, and childhood cancers

    PubMed Central

    Knox, E G

    2006-01-01

    Study objectives To locate geographical sources of engine exhaust emissions in Great Britain and to link them with the birth addresses of children dying from cancer. To estimate the cancer initiating roles of nearby roads and railways and to measure effective ranges. Design Birth and death addresses of all children born between 1955 and 1980 in Great Britain, and dying from leukaemia or other cancer during those years, were linked to locations of railway stations, bus stations, ferry terminals, railways, roads, canals, and rivers. Nearest distances to births and deaths were measured, and migration data relating to children who had moved house were analysed. Excesses of close to hazard birth addresses, compared with close to hazard death addresses, indicate a high prenatal or early postnatal risk of cancer initiation. Setting and subjects Child cancer birth and death addresses and their map references were extracted from an earlier inquiry. Map references of putative hazards were downloaded from the Ordnance Survey national digital map of Great Britain. These data are recorded to a precision of one metre and have ground accuracies around 20 metres. Main results Significant birth excesses were found within short distances of bus stations, railway stations, ferries, railways, and A,B class roads, with a relative risk of 2.1 within 100 m, tapering to neutral after 3.0 km. About 24% of child cancers were attributable to these joint birth proximities. Roads exerted the major effect. Conclusions Child cancer initiations are strongly determined by prenatal or early postnatal exposures to engine exhaust gases, probably through maternal inhalation and accumulation of carcinogens over many months. The main active substance is probably 1,3‐butadiene. PMID:16415262

  18. High-Luminance Road Surfaces,

    DTIC Science & Technology

    1980-12-01

    properties and anorthosites are lighter in color. The field tests have confirmed the positive effect of a light-colored road surface or a light- colored...possibilities of using some light-colored rock materials that could not previously have been recommended, 7 including anorthosites and quartzites. The former...values (%) with a reflect: i meter on wet agregate specimens, size fraction 0.149 - 0.2 ,7 mm. Aggregate Luminosity (% of MgO white) Anorthosite 45

  19. pH dependent salinity-boron interactions impact yield, biomass, evapotranspiration and boron uptake in broccoli (Brassica oleracea L.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil pH is known to influence many important biochemical processes in plants and soils, however its role in salinity - boron interactions affecting plant growth and ion relations has not been examined. The purpose of this research was to evaluate the interactive effects of salinity, boron and soil ...

  20. Effects of Steam Environment on Creep Behavior of Nextel™610/Monazite/Alumina Composite at 1,100°C

    NASA Astrophysics Data System (ADS)

    Ruggles-Wrenn, Marina B.; Yeleser, Tufan; Fair, Geoff E.; Davis, Janet B.

    2009-12-01

    The tensile creep behavior of a N610™/LaPO4/Al2O3 composite was investigated at 1,100°C in laboratory air and in steam. The composite consists of a porous alumina matrix reinforced with Nextel 610 fibers woven in an eight-harness satin weave fabric and coated with monazite. The tensile stress-strain behavior was investigated and the tensile properties measured at 1,100°C. The addition of monazite coating resulted in ~33% improvement in ultimate tensile strength (UTS) at 1,100°C. Tensile creep behavior was examined for creep stresses in the 32-72 MPa range. Primary and secondary creep regimes were observed in all tests. Minimum creep rate was reached in all tests. In air, creep strains remained below 0.8% and creep strain rates approached 2 × 10-8 s-1. Creep run-out defined as 100 h at creep stress was achieved in all tests conducted in air. The presence of steam accelerated creep rates and significantly reduced creep lifetimes. In steam, creep strain reached 2.25%, and creep strain rate approached 2.6 × 10-6 s-1. In steam, creep run-out was not achieved. The retained strength and modulus of all specimens that achieved run-out were characterized. Comparison with results obtained for N610™/Al2O3 (control) specimens revealed that the use of the monazite coating resulted in considerable improvement in creep resistance at 1,100°C both in air and in steam. Composite microstructure, as well as damage and failure mechanisms were investigated.

  1. Wettability of Pyrolytic Boron Nitride by Aluminum

    NASA Technical Reports Server (NTRS)

    Chiaramonte, Francis P.; Rosenthal, Bruce N.

    1991-01-01

    The wetting of pyrolytic boron nitride by molten 99.9999 percent pure aluminum was investigated by using the sessile drop method in a vacuum operating at approximately 660 micro-Pa at temperatures ranging from 700 to 1000 C. The equilibrium contact angle decreased with an increase in temperature. For temperatures at 900 C or less, the equilibrium contact angle was greater than 90 deg. At 1000 C a nonwetting-to-wetting transition occurred and the contact angle stabilized at 49 deg.

  2. Method for exfoliation of hexagonal boron nitride

    NASA Technical Reports Server (NTRS)

    Lin, Yi (Inventor); Connell, John W. (Inventor)

    2012-01-01

    A new method is disclosed for the exfoliation of hexagonal boron nitride into mono- and few-layered nanosheets (or nanoplatelets, nanomesh, nanoribbons). The method does not necessarily require high temperature or vacuum, but uses commercially available h-BN powders (or those derived from these materials, bulk crystals) and only requires wet chemical processing. The method is facile, cost efficient, and scalable. The resultant exfoliated h-BN is dispersible in an organic solvent or water thus amenable for solution processing for unique microelectronic or composite applications.

  3. Boron nitride zigzag nanoribbons: optimal thermoelectric systems.

    PubMed

    Zberecki, K; Swirkowicz, R; Barnaś, J

    2015-09-14

    Conventional and spin related thermoelectric effects in zigzag boron nitride nanoribbons are studied theoretically within the Density Functional Theory (DFT) approach. Nanoribbons with edges passivated with hydrogen, as well as those with bare edges are analyzed. It is shown that one spin channel in the nanoribbons of 0HB-0HN and 2HB-1HN types becomes nonconductive slightly above the Fermi level, and therefore such nanoribbons reveal remarkable spin related thermoelectric phenomena and are promising materials for thermoelectric nanodevices. Thermoelectricity in BN nanoribbons of other types is less efficient and therefore these materials are less interesting for applications.

  4. Boron nitride nanomaterials for thermal management applications.

    PubMed

    Meziani, Mohammed J; Song, Wei-Li; Wang, Ping; Lu, Fushen; Hou, Zhiling; Anderson, Ankoma; Maimaiti, Halidan; Sun, Ya-Ping

    2015-05-18

    Hexagonal boron nitride nanosheets (BNNs) are analogous to their two-dimensional carbon counterparts in many materials properties, in particular, ultrahigh thermal conductivity, but also offer some unique attributes, including being electrically insulating, high thermal stability, chemical and oxidation resistance, low color, and high mechanical strength. Significant recent advances in the production of BNNs, understanding of their properties, and the development of polymeric nanocomposites with BNNs for thermally conductive yet electrically insulating materials and systems are highlighted herein. Major opportunities and challenges for further studies in this rapidly advancing field are also discussed.

  5. Carbon or boron modified titanium silicide

    DOEpatents

    Thom, Andrew J.; Akinc, Mufit

    1996-12-03

    A titanium silicide material based on Ti.sub.5 Si.sub.3 intermetallic compound exhibits substantially improved oxidative stability at elevated temperatures. In particular, carbon is added to a Ti.sub.5 Si.sub.3 base material in an amount (e.g. about 0.3 to about 3.6 weight % C) effective to impart substantially improved oxidative stability at elevated temperatures, such as about 1000.degree. C. Boron is added to a Ti.sub.5 Si.sub.3 base material in an amount (e.g. about 0.3 to about 3.3 weight % B) to this same end.

  6. Carbon or boron modified titanium silicide

    DOEpatents

    Thom, A.J.; Akinc, M.

    1998-07-14

    A titanium silicide material based on Ti{sub 5}Si{sub 3} intermetallic compound exhibits substantially improved oxidative stability at elevated temperatures. In particular, carbon is added to a Ti{sub 5}Si{sub 3} base material in an amount (e.g. about 0.3 to about 3.6 weight % C) effective to impart substantially improved oxidative stability at elevated temperatures, such as about 1000 C. Boron is added to a Ti{sub 5}Si{sub 3} base material in an amount (e.g. about 0.3 to about 3.3 weight % B) to this same end. 3 figs.

  7. Carbon or boron modified titanium silicide

    DOEpatents

    Thom, Andrew J.; Akinc, Mufit

    1997-12-02

    A titanium silicide material based on Ti.sub.5 Si.sub.3 intermetallic compound exhibits substantially improved oxidative stability at elevated temperatures. In particular, carbon is added to a Ti.sub.5 Si.sub.3 base material in an amount (e.g. about 0.3 to about 3.6 weight % C) effective to impart substantially improved oxidative stability at elevated temperatures, such as about 1000.degree. C. Boron is added to a Ti.sub.5 Si.sub.3 base material in an amount (e.g. about 0.3 to about 3.3 weight % B) to this same end.

  8. Carbon or boron modified titanium silicide

    DOEpatents

    Thom, A.J.; Akinc, M.

    1997-12-02

    A titanium silicide material based on Ti{sub 5}Si{sub 3} intermetallic compound exhibits substantially improved oxidative stability at elevated temperatures. In particular, carbon is added to a Ti{sub 5}Si{sub 3} base material in an amount (e.g. about 0.3 to about 3.6 weight % C) effective to impart substantially improved oxidative stability at elevated temperatures, such as about 1000 C. Boron is added to a Ti{sub 5}Si{sub 3} base material in an amount (e.g. about 0.3 to about 3.3 weight % B) to this same end. 3 figs.

  9. Carbon or boron modified titanium silicide

    DOEpatents

    Thom, A.J.; Akinc, M.

    1996-12-03

    A titanium silicide material based on Ti{sub 5}Si{sub 3} intermetallic compound exhibits substantially improved oxidative stability at elevated temperatures. In particular, carbon is added to a Ti{sub 5}Si{sub 3} base material in an amount (e.g. about 0.3 to about 3.6 weight % C) effective to impart substantially improved oxidative stability at elevated temperatures, such as about 1000 C. Boron is added to a Ti{sub 5}Si{sub 3} base material in an amount (e.g. about 0.3 to about 3.3 weight % B) to this same end. 3 figs.

  10. Carbon or boron modified titanium silicide

    DOEpatents

    Thom, Andrew J.; Akinc, Mufit

    1998-07-14

    A titanium silicide material based on Ti.sub.5 Si.sub.3 intermetallic compound exhibits substantially improved oxidative stability at elevated temperatures. In particular, carbon is added to a Ti.sub.5 Si.sub.3 base material in an amount (e.g. about 0.3 to about 3.6 weight % C) effective to impart substantially improved oxidative stability at elevated temperatures, such as about 1000.degree. C. Boron is added to a Ti.sub.5 Si.sub.3 base material in an amount (e.g. about 0.3 to about 3.3 weight % B) to this same end.

  11. Compositions for boron delivery to mammalian tissue

    DOEpatents

    Hawthorne, M. Frederick; Feaks, Debra Arlene; Shelly, Kenneth John

    2001-01-01

    Boron neutron capture therapy can utilize X.sub.y B.sub.20 H.sub.17 L where X is an alkali metal, y is 1 to 4, and L is a two electron donor such as NH.sub.3, and Na.sub.2 B.sub.10 H.sub.9 NCO, among others. These borane salts may be used free or encapsulated in liposomes. Liposomes may also have embedded within their bilayers carboranes to increase the amount of delivered .sup.10 B and/or to increase the tumor specificity of the liposome.

  12. Recent advancements in boron nitride nanotubes.

    PubMed

    Wang, Jiesheng; Lee, Chee Huei; Yap, Yoke Khin

    2010-10-01

    This article provides a concise review of the recent research advancements in boron nitride nanotubes (BNNTs) with a comprehensive list of references. As the motivation of the field, we first summarize some of the attractive properties and potential applications of BNNTs. Then, latest discoveries on the properties, applications, and synthesis of BNNTs are discussed. In particular, we focus on low-temperature and patterned growth, and mass production of BNNTs, since these are the major challenges that have hindered investigation of the properties and application of BNNTs for the past decade. Finally, perspectives of future research on BNNTs are discussed.

  13. Fe nanowire encapsulated in boron nitride nanotubes

    NASA Astrophysics Data System (ADS)

    Koi, Naruhiro; Oku, Takeo; Nishijima, Masahiko

    2005-11-01

    Boron nitride (BN) nanotubes, nanohorns, nanocoils were synthesized by annealing Fe 4N and B powders at 1000 °C for 1 h in nitrogen gas atmosphere. Especially, Fe-filled BN nanotubes were produced, and investigated by high-resolution electron microscopy, high-angle annular dark-field scanning transmission electron microscopy, electron diffraction and energy dispersive X-ray spectroscopy, which indicates that the [110] of Fe is parallel to the BN nanotube axis. Formation mechanism of Fe-filled BN nanotube was speculated based on these results.

  14. Recent advancements in boron nitride nanotubes

    NASA Astrophysics Data System (ADS)

    Wang, Jiesheng; Lee, Chee Huei; Yap, Yoke Khin

    2010-10-01

    This article provides a concise review of the recent research advancements in boron nitride nanotubes (BNNTs) with a comprehensive list of references. As the motivation of the field, we first summarize some of the attractive properties and potential applications of BNNTs. Then, latest discoveries on the properties, applications, and synthesis of BNNTs are discussed. In particular, we focus on low-temperature and patterned growth, and mass production of BNNTs, since these are the major challenges that have hindered investigation of the properties and application of BNNTs for the past decade. Finally, perspectives of future research on BNNTs are discussed.

  15. Stability analysis of zigzag boron nitride nanoribbons

    SciTech Connect

    Rai, Hari Mohan Late, Ravikiran; Saxena, Shailendra K.; Kumar, Rajesh; Sagdeo, Pankaj R.; Jaiswal, Neeraj K.; Srivastava, Pankaj

    2015-05-15

    We have explored the structural stability of bare and hydrogenated zigzag boron nitride nanoribbons (ZBNNRs). In order to investigate the structural stability, we calculate the cohesive energy for bare, one-edge and both edges H-terminated ZBNNRs with different widths. It is found that the ZBNNRs with width Nz=8 are energetically more favorable than the lower-width counterparts (Nz<8). Bare ZBNNRs have been found energetically most stable as compared to the edge terminated ribbons. Our analysis reveals that the structural stability is a function of ribbon-width and it is not affected significantly by the type of edge-passivation (one-edge or both-edges)

  16. Magnesium doping of boron nitride nanotubes

    DOEpatents

    Legg, Robert; Jordan, Kevin

    2015-06-16

    A method to fabricate boron nitride nanotubes incorporating magnesium diboride in their structure. In a first embodiment, magnesium wire is introduced into a reaction feed bundle during a BNNT fabrication process. In a second embodiment, magnesium in powder form is mixed into a nitrogen gas flow during the BNNT fabrication process. MgB.sub.2 yarn may be used for superconducting applications and, in that capacity, has considerably less susceptibility to stress and has considerably better thermal conductivity than these conventional materials when compared to both conventional low and high temperature superconducting materials.

  17. Seismic risk assessment for road in Indonesia

    NASA Astrophysics Data System (ADS)

    Toyfur, Mona Foralisa; Pribadi, Krishna S.

    2016-05-01

    Road networks in Indonesia consist of 446,000 km of national, provincial and local roads as well as toll highways. Indonesia is one of countries that exposed to various natural hazards, such as earthquakes, floods, landslides, etc. Within the Indonesian archipelago, several global tectonic plates interact, such as the Indo-Australian, Pacific, Eurasian, resulting in a complex geological setting, characterized by the existence of seismically active faults and subduction zones and a chain of more than one hundred active volcanoes. Roads in Indonesia are vital infrastructure needed for people and goods movement, thus supporting community life and economic activities, including promoting regional economic development. Road damages and losses due to earthquakes have not been studied widely, whereas road disruption caused enormous economic damage. The aim of this research is to develop a method to analyse risk caused by seismic hazard to roads. The seismic risk level of road segment is defined using an earthquake risk index, adopting the method of Earthquake Disaster Risk Index model developed by Davidson (1997). Using this method, road segments' risk level can be defined and compared, and road risk map can be developed as a tool for prioritizing risk mitigation programs for road networks in Indonesia.

  18. New insight in boron chemistry: Application in two-photon absorption

    NASA Astrophysics Data System (ADS)

    Bolze, F.; Hayek, A.; Sun, X. H.; Baldeck, P. L.; Bourgogne, C.; Nicoud, J.-F.

    2011-07-01

    Two groups of one-dimensional (1D) boron containing two-photon absorbing fluorophores have been prepared and characterized. One group includes boron atoms incorporated in the conjugated or pseudo conjugated central core and the other contain a boron cluster as an acceptor group at one end of the fluorophores. Two boron containing central cores (with two boron atoms) have been explored: the cyclodiborazane and the pyrazabole moieties. The chosen boron cluster, p-carborane, contains 10 boron atoms. All the prepared fluorophores present high two-photon absorption cross-sections. Some water-soluble as well as lipophylic dyes have been prepared and used in bio-imaging.

  19. Boron-induced reconstructions of Si(100) investigated by scanning tunneling microscopy

    NASA Astrophysics Data System (ADS)

    Wang, Yajun; Hamers, Robert J.

    1994-12-01

    The local geometric and electronic structures of boron-induced reconstructions produced by thermal decomposition of diborane and decaborane on Si(001) has been investigated using scanning tunneling microscopy. STM images show that boron induces several related reconstructions, arising from ordered arrangements of simple structural subunits. These boron-induced atomic rearrangements order even at very low boron exposures, leading to a striking spatial segregation of boron on the surface. Similar reconstructions are observed using diborane and decaborane as boron precursors. Annealing at 1000 Kelvin for 90 seconds substantially improves the surface ordering, without significant diffusion of boron from the surface to the bulk.

  20. Application of cycloaddition reactions to the syntheses of novel boron compounds.

    PubMed

    Zhu, Yinghuai; Siwei, Xiao; Maguire, John A; Hosmane, Narayan S

    2010-12-21

    This review covers the application of cycloaddition reactions in forming the boron-containing compounds such as symmetric star-shaped boron-enriched dendritic molecules, nano-structured boron materials and aromatic boronic esters. The resulting boron compounds are potentially important reagents for both materials science and medical applications such as in boron neutron capture therapy (BNCT) in cancer treatment and as drug delivery agents and synthetic intermediates for carbon-carbon cross-coupling reactions. In addition, the use of boron cage compounds in a number of cycloaddition reactions to synthesize unique aromatic species will be reviewed briefly.

  1. Efficient Boron-Carbon-Nitrogen Nanotube Formation Via Combined Laser-Gas Flow Levitation

    NASA Technical Reports Server (NTRS)

    Whitney, R. Roy (Inventor); Jordan, Kevin (Inventor); Smith, Michael W. (Inventor)

    2015-01-01

    A process for producing boron nitride nanotubes and/or boron-carbon-nitrogen nanotubes of the general formula BxCyNz. The process utilizes a combination of laser light and nitrogen gas flow to support a boron ball target during heating of the boron ball target and production of a boron vapor plume which reacts with nitrogen or nitrogen and carbon to produce boron nitride nanotubes and/or boron-carbon-nitrogen nanotubes of the general formula BxCyNz.

  2. Efficient boron-carbon-nitrogen nanotube formation via combined laser-gas flow levitation

    DOEpatents

    Whitney, R Roy; Jordan, Kevin; Smith, Michael W

    2015-03-24

    A process for producing boron nitride nanotubes and/or boron-carbon-nitrogen nanotubes of the general formula B.sub.xC.sub.yN.sub.z. The process utilizes a combination of laser light and nitrogen gas flow to support a boron ball target during heating of the boron ball target and production of a boron vapor plume which reacts with nitrogen or nitrogen and carbon to produce boron nitride nanotubes and/or boron-carbon-nitrogen nanotubes of the general formula B.sub.xC.sub.yN.sub.z.

  3. Efficient boron nitride nanotube formation via combined laser-gas flow levitation

    DOEpatents

    Whitney, R. Roy; Jordan, Kevin; Smith, Michael

    2014-03-18

    A process for producing boron nitride nanotubes and/or boron-carbon-nitrogen nanotubes of the general formula B.sub.xC.sub.yN.sub.z. The process utilizes a combination of laser light and nitrogen gas flow to support a boron ball target during heating of the boron ball target and production of a boron vapor plume which reacts with nitrogen or nitrogen and carbon to produce boron nitride nanotubes and/or boron-carbon-nitrogen nanotubes of the general formula B.sub.xC.sub.yN.sub.z.

  4. Efficient Boron Nitride Nanotube Formation via Combined Laser-Gas Flow Levitation

    NASA Technical Reports Server (NTRS)

    Whitney, R. Roy (Inventor); Jordan, Kevin (Inventor); Smith, Michael W. (Inventor)

    2014-01-01

    A process for producing boron nitride nanotubes and/or boron-carbon-nitrogen nanotubes of the general formula B(sub x)C(sub y)N(sub z) The process utilizes a combination of laser light and nitrogen gas flow to support a boron ball target during heating of the boron ball target and production of a boron vapor plume which reacts with nitrogen or nitrogen and carbon to produce boron nitride nanotubes and/or boron-carbon-nitrogen nanotubes of the general formula B(sub x)C(sub y)N(sub z).

  5. Detection of boron removal capacities of different microorganisms in wastewater and effective removal process.

    PubMed

    Laçin, Bengü; Ertit Taştan, Burcu; Dönmez, Gönül

    2015-01-01

    In this study boron removal capacities of different microorganisms were tested. Candida tropicalis, Rhodotorula mucilaginosa, Micrococcus luteus, Bacillus thuringiensis, Bacillus cereus, Bacillus megaterium, Bacillus pumilus, Pseudomonas aeruginosa and Aspergillus versicolor were examined for their boron bioaccumulation capacities in simulated municipal wastewater. A. versicolor and B. cereus were found as the most boron-tolerant microorganisms in the experiments. Also boron bioaccumulation yield of A. versicolor was 49.25% at 15 mg/L boron concentration. On the other hand biosorption experiments revealed that A. versicolor was more capable of boron removal in inactive form at the highest boron concentrations. In this paper maximum boron bioaccumulation yield was detected as 39.08% at 24.17 mg/L and the maximum boron biosorption yield was detected as 41.36% at 24.01 mg/L boron concentrations.

  6. Boron isotope systematics of hydrothermal fluids from submarine hydrothermal systems

    NASA Astrophysics Data System (ADS)

    Yamaoka, K.; Hong, E.; Ishikawa, T.; Gamo, T.; Kawahata, H.

    2013-12-01

    Boron is highly mobile in submarine hydrothermal systems and useful to trace the process of water-rock reaction. In this study, we measured the boron content and isotopic composition of vent fluids collected from arc-backarc hydrothermal systems in the western Pacific. In sediment-starved hydrothermal systems (Manus Basin, Suiyo Seamount, and Mariana Trough), the boron content and isotopic composition of vent fluids are dependent on type of host rock. The end member fluids from MORB-like basalt-hosted Vienna Woods in the Manus Basin showed low boron content and high δ11B value (0.53 mM, 29.8‰), while dacite-hosted PACMANUS and the Suiyo Seamount showed high boron contents and low δ11B values (1.45 and 1.52 mM, 13.6 and 18.5‰, respectively). The Alice Springs and Forecast Vent field in the Mariana Trough showed values intermediate between them (0.72 and 0.63 mM, 19.9 and 24.0‰, respectively), reflecting reaction of seawater and basalt influenced by slab material. In phase separated hydrothermal systems (North Fiji Basin), boron content and isotopic composition of vent fluids (0.44-0.56 mM, 34.5-35.9‰) were similar to those in the Vienna Woods. Considering little fractionation of boron and boron isotope during phase separation demonstrated by the previous experimental studies, it is suggested that the host rock in the North Fiji Basin is MORB-like basalt. In sediment-hosted hydrothermal system (Okinawa Trough), the reaction with boron-enriched sediment following seawater-rock reaction resulted in significantly high boron contents and low δ11B values of vent fluids (4.4-5.9 mM, 1.5-2.6‰). The water-sediment ratio was estimated to be ~2. In spite of the different geological settings, the end member fuids from all vent fields are enriched in B relative to seawater (0.41 mM, 39.6‰) and the δ11B values are inversely propotional to the boron concentrations. It suggests that boron isotopic composition of vent fluid predominantly depends on the amount of

  7. β-Rhombohedral Boron: At the Crossroads of the Chemistry of Boron and the Physics of Frustration [Boron: a frustrated element

    SciTech Connect

    Ogitsu, Tadashi; Schwegler, Eric; Galli, Giulia

    2013-05-08

    In the periodic table boron occupies a peculiar, crossover position: on the first row, it is surrounded by metal forming elements on the left and by non-metals on the right. In addition, it is the only non-metal of the third column. Therefore it is perhaps not surprising that the crystallographic structure and topology of its stable allotrope at room temperature (β-boron) are not shared by any other element, and are extremely complex. The formidable intricacy of β- boron, with interconnecting icosahedra, partially occupied sites, and an unusually large number of atoms per unit cell (more than 300) has been known for more than 40 years. Nevertheless boron remains the only element purified in significant quantities whose ground state geometry has not been completely determined by experiments. However theoretical progress reported in the last decade has shed light on numerous properties of elemental boron, leading to a thorough characterization of its structure at ambient conditions, as well as of its electronic and thermodynamic properties. This review discusses in detail the properties of β-boron, as inferred from experiments and the ab-initio theories developed in the last decade.

  8. Invasive Brown Treesnake movements at road edges indicate road-crossing avoidance

    USGS Publications Warehouse

    Siers, Shane R; Savidge, Julie S; Reed, Robert N.

    2014-01-01

    Roads have significant impacts on the dispersal of wildlife. Although this poses a threat to the abundance and diversity of desirable flora and fauna, it also affords some opportunity for enhancing control of invasive species. Roads are the most common terrain features that may affect the rate of landscape-scale movements of invasive Brown Treesnakes (Boiga irregularis) throughout Guam. We radio tracked 45 free-ranging Brown Treesnakes in close proximity to two roads in Guam and recorded instances where daily relocations of snakes spanned roads. Then we reconstructed observed movement histories with randomized turning angles, which served as a useful null hypothesis for assessing the effect of roads or road edge habitat on Brown Treesnake movement patterns. Random walk simulations demonstrated that Brown Treesnakes crossed these roads at a rate far lower than would be expected if snake movement was random with respect to roads and road edge habitat. We discuss two alternative hypotheses for these results: 1) habitat gaps posed by roads physically or behaviorally restrict snake movement; or 2) road edges provide preferred foraging habitat from which snakes are reluctant to depart. Because roads often form the boundaries of jurisdictional and management units, the effects of roads on the movement of invasive Brown Treesnakes will influence the prospects for success of future landscape-level suppression efforts.

  9. Process to produce silicon carbide fibers using a controlled concentration of boron oxide vapor

    NASA Technical Reports Server (NTRS)

    Barnard, Thomas Duncan (Inventor); Lipowitz, Jonathan (Inventor); Nguyen, Kimmai Thi (Inventor)

    2001-01-01

    A process for producing polycrystalline silicon carbide by heating an amorphous ceramic fiber that contains silicon and carbon in an environment containing boron oxide vapor. The boron oxide vapor is produced in situ by the reaction of a boron containing material such as boron carbide and an oxidizing agent such as carbon dioxide, and the amount of boron oxide vapor can be controlled by varying the amount and rate of addition of the oxidizing agent.

  10. Process to produce silicon carbide fibers using a controlled concentration of boron oxide vapor

    NASA Technical Reports Server (NTRS)

    Barnard, Thomas Duncan (Inventor); Lipowitz, Jonathan (Inventor); Nguyen, Kimmai Thi (Inventor)

    2000-01-01

    A process for producing polycrystalline silicon carbide includes heating an amorphous ceramic fiber that contains silicon and carbon in an environment containing boron oxide vapor. The boron oxide vapor is produced in situ by the reaction of a boron containing material such as boron carbide and an oxidizing agent such as carbon dioxide, and the amount of boron oxide vapor can be controlled by varying the amount and rate of addition of the oxidizing agent.

  11. Power Burst Facility/Boron Neutron Capture Therapy Program for cancer treatment

    SciTech Connect

    Ackermann, A.L.; Dorn, R.V. III.

    1990-08-01

    This report discusses monthly progress in the Power Boron Facility/Boron Neutron Capture Therapy (PBF/BNCT) Program for Cancer Treatment. Highlights of the PBF/BNCT Program during August 1990 include progress within the areas of: Gross Boron Analysis in Tissue, Blood, and Urine, boron microscopic (subcellular) analytical development, noninvasive boron quantitative determination, analytical radiation transport and interaction modeling for BNCT, large animal model studies, neutron source and facility preparation, administration and common support and PBF operations.

  12. Boron monoxide-hydrogen peroxide fuel cell

    SciTech Connect

    Struthers, R.C.

    1985-01-08

    A primary fuel cell including an elongate case defining a central ion exchange compartment with opposite ends and containing a liquid ionolyte. The case next defines an anode section at one end of the case and including a gas compartment containing boron monoxide gas fuel, a liquid compartment between the gas compartment and the ion exchange compartment and containing a liquid anolyte. The ionolyte and anolyte are separated by a cationic membrane. The gas and liquid compartments are separated by an anode plate including an electron collector part, a catalyst material carried by said part and a gas permeable hydrophobic membrane between the boron monoxide gas and the catalyst material. The cell further includes a cathode section at the other end of the case defining a cathode fuel compartment containing a fluid cathode fuel and a cathode plate between and separating the cathode fuel and the ionolyte in the ion exchange compartment. The cathode plate includes an electron distributor part and a catalyst material carried by the distributor part. If the cathode fuel is a gas fuel, the cathode plate also includes a gas permeable hydrophobic membrane between the catalyst material carried by the distributor part and the cathode fuel. The cathode and anode plates have terminals connected with a related external electric circuit.

  13. Microdosimetry for Boron Neutron Capture Therapy

    SciTech Connect

    Maughan, R.L.; Kota, C.

    2000-09-05

    The specific aims of the research proposal were as follows: (1) To design and construct small volume tissue equivalent proportional counters for the dosimetry and microdosimetry of high intensity thermal and epithermal neutron beams used in BNCT, and of modified fast neutron beams designed for boron neutron capture enhanced fast neutron therapy (BNCEFNT). (2) To develop analytical methods for estimating the biological effectiveness of the absorbed dose in BNCT and BNCEFNT based on the measured microdosimetric spectra. (3) To develop an analytical framework for comparing the biological effectiveness of different epithermal neutron beams used in BNCT and BNCEFNT, based on correlated sets of measured microdosimetric spectra and radiobiological data. Specific aims (1) and (2) were achieved in their entirety and are comprehensively documented in Jay Burmeister's Ph.D. dissertation entitled ''Specification of physical and biologically effective absorbed dose in radiation therapies utilizing the boron neutron capture reaction'' (Wayne State University, 1999). Specific aim (3) proved difficult to accomplish because of a lack of sufficient radiobiological data.

  14. Techniques for increasing boron fiber fracture strain

    NASA Technical Reports Server (NTRS)

    Dicarlo, J. A.

    1977-01-01

    Improvement in the strain-to-failure of chemical-vapor-deposition boron fibers is shown possible by contracting the tungsten boride core region and its inherent flaws. Results of three methods are presented in which etching and thermal-processing techniques were employed to achieve core flaw contraction by internal stresses available in the boron sheath. After commercially and treatment-induced surface flaws were removed from 203-micron (8-mil) fibers, the core flaw was observed to be essentially the only source of fiber fracture. Thus, fiber strain-to-failure was found to improve by an amount equal to the treatment-induced contraction on the core flaw. To date, average fracture strains and stresses greater than 1.4% and 5.5 GN/sq m (800 ksi), respectively, have been achieved. Commercial feasibility considerations suggest as the most cost-effective technique that method in which as-produced fibers are given a rapid heat treatment above 700 C. Preliminary results concerning the contraction kinetics and fracture behavior observed with this technique are presented and discussed for both high-vacuum and argon-gas heat-treatment environments.

  15. Boron-10 ABUNCL Prototype Initial Testing

    SciTech Connect

    Kouzes, Richard T.; Ely, James H.; Lintereur, Azaree T.; Siciliano, Edward R.

    2012-12-01

    The Department of Energy Office of Nuclear Safeguards and Security (NA-241) is supporting the project Coincidence Counting With Boron-Based Alternative Neutron Detection Technology at Pacific Northwest National Laboratory (PNNL) for the development of a 3He proportional counter alternative neutron coincidence counter. The goal of this project is to design, build and demonstrate a system based upon 10B-lined proportional tubes in a configuration typical for 3He-based coincidence counter applications. This report provides results of initial testing of an Alternative Boron-Based Uranium Neutron Coincidence Collar (ABUNCL) design built by General Electric Reuter-Stokes. Several configurations of the ABUNCL models, which use 10B-lined proportional counters in place of 3He proportional counters for the neutron detection elements, were previously reported. The ABUNCL tested is of a different design than previously modeled. Initial experimental testing of the as-delivered passive ABUNCL was performed, and modeling will be conducted. Testing of the system reconfigured for active testing will be performed in the near future, followed by testing with nuclear fuel.

  16. Boron modified molybdenum silicide and products

    DOEpatents

    Meyer, M.K.; Akinc, M.

    1999-02-02

    A boron-modified molybdenum silicide material is disclosed having the composition comprising about 80 to about 90 weight % Mo, about 10 to about 20 weight % Si, and about 0.1 to about 2 weight % B and a multiphase microstructure including Mo{sub 5}Si{sub 3} phase as at least one microstructural component effective to impart good high temperature creep resistance. The boron-modified molybdenum silicide material is fabricated into such products as electrical components, such as resistors and interconnects, that exhibit oxidation resistance to withstand high temperatures in service in air as a result of electrical power dissipation, electrical resistance heating elements that can withstand high temperatures in service in air and other oxygen-bearing atmospheres and can span greater distances than MoSi{sub 2} heating elements due to improved creep resistance, and high temperature structural members and other fabricated components that can withstand high temperatures in service in air or other oxygen-bearing atmospheres while retaining creep resistance associated with Mo{sub 5}Si{sub 3} for structural integrity. 7 figs.

  17. Boron modified molybdenum silicide and products

    DOEpatents

    Meyer, Mitchell K.; Akinc, Mufit

    1999-02-02

    A boron-modified molybdenum silicide material having the composition comprising about 80 to about 90 weight % Mo, about 10 to about 20 weight % Si, and about 0.1 to about 2 weight % B and a multiphase microstructure including Mo.sub.5 Si.sub.3 phase as at least one microstructural component effective to impart good high temperature creep resistance. The boron-modified molybdenum silicide material is fabricated into such products as electrical components, such as resistors and interconnects, that exhibit oxidation resistance to withstand high temperatures in service in air as a result of electrical power dissipation, electrical resistance heating elements that can withstand high temperatures in service in air and other oxygen-bearing atmospheres and can span greater distances than MoSi.sub.2 heating elements due to improved creep resistance, and high temperature structural members and other fabricated components that can withstand high temperatures in service in air or other oxygen-bearing atmospheres while retaining creep resistance associated with Mo.sub.5 Si.sub.3 for structural integrity.

  18. Analysis of boron carbides' electronic structure

    NASA Technical Reports Server (NTRS)

    Howard, Iris A.; Beckel, Charles L.

    1986-01-01

    The electronic properties of boron-rich icosahedral clusters were studied as a means of understanding the electronic structure of the icosahedral borides such as boron carbide. A lower bound was estimated on bipolaron formation energies in B12 and B11C icosahedra, and the associated distortions. While the magnitude of the distortion associated with bipolaron formation is similar in both cases, the calculated formation energies differ greatly, formation being much more favorable on B11C icosahedra. The stable positions of a divalent atom relative to an icosahedral borane was also investigated, with the result that a stable energy minimum was found when the atom is at the center of the borane, internal to the B12 cage. If incorporation of dopant atoms into B12 cages in icosahedral boride solids is feasible, novel materials might result. In addition, the normal modes of a B12H12 cluster, of the C2B10 cage in para-carborane, and of a B12 icosahedron of reduced (D sub 3d) symmetry, such as is found in the icosahedral borides, were calculated. The nature of these vibrational modes will be important in determining, for instance, the character of the electron-lattice coupling in the borides, and in analyzing the lattice contribution to the thermal conductivity.

  19. Using Ylide Functionalization to Stabilize Boron Cations

    PubMed Central

    Scherpf, Thorsten; Feichtner, Kai‐Stephan

    2017-01-01

    Abstract The metalated ylide YNa [Y=(Ph3PCSO2Tol)−] was employed as X,L‐donor ligand for the preparation of a series of boron cations. Treatment of the bis‐ylide functionalized borane Y2BH with different trityl salts or B(C6F5)3 for hydride abstraction readily results in the formation of the bis‐ylide functionalized boron cation [Y−B−Y]+ (2). The high donor capacity of the ylide ligands allowed the isolation of the cationic species and its characterization in solution as well as in solid state. DFT calculations demonstrate that the cation is efficiently stabilized through electrostatic effects as well as π‐donation from the ylide ligands, which results in its high stability. Despite the high stability of 2 [Y−B−Y]+ serves as viable source for the preparation of further borenium cations of type Y2B+←LB by addition of Lewis bases such as amines and amides. Primary and secondary amines react to tris(amino)boranes via N−H activation across the B−C bond. PMID:28185370

  20. Boron neutron capture therapy for malignant melanoma: An experimental approach

    SciTech Connect

    Larsson, B.S.; Larsson, B.; Roberto, A. )

    1989-07-01

    Previous studies have shown that some thioamides, e.g., thiouracil, are incorporated as false precursors into melanin during its synthesis. If boronated analogs of the thioamides share this property, the melanin of melanotic melanomas offers a possibility for specific tumoural uptake and retention of boron as a basis for neutron capture therapy. We report on the synthesis of boronated 1H-1,2,4-triazole-3-thiol (B-TZT), boronated 5-carboxy-2-thiouracil (B-CTU), and boronated 5-diethylaminomethyl-2-thiouracil (B-DEAMTU) and the localization of these substances in melanotic melanomas transplanted to mice. The distribution in the mice was studied by boron neutron capture radiography. B-TZT and B-CTU showed the highest tumour:normal tissue concentration ratios, with tumour:liver ratios of about 4 and tumour:muscle ratios of about 14; B-DEAMTU showed corresponding ratios of 1.4 and 5, respectively. The absolute concentration of boron in the tumours, however, was more than three times higher in the mice injected with B-TZT, compared with B-CTU. The results suggest that B-TZT may be the most promising compound of the three tested with regard to possible therapy of melanotic melanomas.

  1. Computational Studies of Physical Properties of Boron Carbide

    SciTech Connect

    Lizhi Ouyang

    2011-09-30

    The overall goal is to provide valuable insight in to the mechanisms and processes that could lead to better engineering the widely used boron carbide which could play an important role in current plight towards greener energy. Carbon distribution in boron carbide, which has been difficult to retrieve from experimental methods, is critical to our understanding of its structure-properties relation. For modeling disorders in boron carbide, we implemented a first principles method based on supercell approach within our G(P,T) package. The supercell approach was applied to boron carbide to determine its carbon distribution. Our results reveal that carbon prefers to occupy the end sites of the 3-atom chain in boron carbide and further carbon atoms will distribute mainly on the equatorial sites with a small percentage on the 3-atom chains and the apex sites. Supercell approach was also applied to study mechanical properties of boron carbide under uniaxial load. We found that uniaxial load can lead to amorphization. Other physical properties of boron carbide were calculated using the G(P,T) package.

  2. Characterization of a boron carbide-based polymer neutron sensor

    NASA Astrophysics Data System (ADS)

    Tan, Chuting; James, Robinson; Dong, Bin; Driver, M. Sky; Kelber, Jeffry A.; Downing, Greg; Cao, Lei R.

    2015-12-01

    Boron is used widely in thin-film solid-state devices for neutron detection. The film thickness and boron concentration are important parameters that relate to a device's detection efficiency and capacitance. Neutron depth profiling was used to determine the film thicknesses and boron-concentration profiles of boron carbide-based polymers grown by plasma enhanced chemical vapor deposition (PECVD) of ortho-carborane (1,2-B10C2H12), resulting in a pure boron carbide film, or of meta-carborane (1,7-B10C2H12) and pyridine (C5H5N), resulting in a pyridine composite film, or of pyrimidine (C4H4N2) resulting in a pure pyrimidine film. The pure boron carbide film had a uniform surface appearance and a constant thickness of 250 nm, whereas the thickness of the composite film was 250-350 nm, measured at three different locations. In the meta-carborane and pyridine composite film the boron concentration was found to increase with depth, which correlated with X-ray photoelectron spectroscopy (XPS)-derived atomic ratios. A proton peak from 14N (n,p)14C reaction was observed in the pure pyrimidine film, indicating an additional neutron sensitivity to nonthermal neutrons from the N atoms in the pyrimidine.

  3. Influence Of Low Boron Core Design On PWR Transient Behavior

    SciTech Connect

    Aleksandrov Papukchiev, Angel; Yubo Liu; Schaefer, Anselm

    2006-07-01

    In conventional pressurized water reactor (PWR) designs, the concentration of boron in primary coolant is limited by the requirement of having a negative moderator density coefficient. As high boron concentrations have significant impact on reactivity feedback properties, design changes to reduce boron concentration in the reactor coolant are of general interest in view of improving PWR inherent safety. In the framework of an investigation into the feasibility of low boron design, a PWR core configuration based on fuel with higher gadolinium (Gd) content has been developed which permits to reduce the natural boron concentration at begin of cycle (BOC) by approx. 50% compared to current German PWR technology. For the assessment of the potential safety advantages, a Loss-of-Feedwater Anticipated Transient Without Scram (ATWS LOFW) has been simulated with the system code ATHLET for two PWR core designs: a low boron design and a standard core design. The most significant difference in the transient performance of both designs is the total primary fluid mass released through the pressurizer (PRZ) valves. It is reduced by a factor of four for the low boron reactor, indicating its improved density reactivity feedback. (authors)

  4. The road plan model: Information model for planning road building activities

    NASA Technical Reports Server (NTRS)

    Azinhal, Rafaela K.; Moura-Pires, Fernando

    1994-01-01

    The general building contractor is presented with an information model as an approach for deriving a high-level work plan of construction activities applied to road building. Road construction activities are represented in a Road Plan Model (RPM), which is modeled in the ISO standard STEP/EXPRESS and adopts various concepts from the GARM notation. The integration with the preceding road design stage and the succeeding phase of resource scheduling is discussed within the framework of a Road Construction Model. Construction knowledge is applied to the road design and the terrain model of the surrounding road infrastructure for the instantiation of the RPM. Issues regarding the implementation of a road planner application supporting the RPM are discussed.

  5. No evidence that boron influences tree species distributions in lowland tropical forests of Panama.

    PubMed

    Turner, Benjamin L; Zalamea, Paul-Camilo; Condit, Richard; Winter, Klaus; Wright, S Joseph; Dalling, James W

    2017-04-01

    It was recently proposed that boron might be the most important nutrient structuring tree species distributions in tropical forests. Here we combine observational and experimental studies to test this hypothesis for lowland tropical forests of Panama. Plant-available boron is uniformly low in tropical forest soils of Panama and is not significantly associated with any of the > 500 species in a regional network of forest dynamics plots. Experimental manipulation of boron supply to seedlings of three tropical tree species revealed no evidence of boron deficiency or toxicity at concentrations likely to occur in tropical forest soils. Foliar boron did not correlate with soil boron along a local scale gradient of boron availability. Fifteen years of boron addition to a tropical forest increased plant-available boron by 70% but did not significantly change tree productivity or boron concentrations in live leaves, wood or leaf litter. The annual input of boron in rainfall accounts for a considerable proportion of the boron in annual litterfall and is similar to the pool of plant-available boron in the soil, and is therefore sufficient to preclude boron deficiency. We conclude that boron does not influence tree species distributions in Panama and presumably elsewhere in the lowland tropics.

  6. Arsenic, Boron, and Fluoride Concentrations in Ground Water in and Near Diabase Intrusions, Newark Basin, Southeastern Pennsylvania

    USGS Publications Warehouse

    Senior, Lisa A.; Sloto, Ronald A.

    2006-01-01

    During an investigation in 2000 by the U.S. Environmental Protection Agency (USEPA) of possible contaminant releases from an industrial facility on Congo Road near Gilbertsville in Berks and Montgomery Counties, southeastern Pennsylvania, concentrations of arsenic and fluoride above USEPA drinking-water standards of 10 ?g/L and 4 mg/L, respectively, and of boron above the USEPA health advisory level of 600 ?g/L were measured in ground water in an area along the northwestern edge of the Newark Basin. In 2003, the USEPA requested technical assistance from the U.S. Geological Survey (USGS) to help identify sources of arsenic, boron, and fluoride in the ground water in the Congo Road area, which included possible anthropogenic releases and naturally occurring mineralization in the local bedrock aquifer, and to identify other areas in the Newark Basin of southeastern Pennsylvania with similarly elevated concentrations of these constituents. The USGS reviewed available data and collected additional ground-water samples in the Congo Road area and four similar hydrogeologic settings. The Newark Basin is the largest of the 13 major exposed Mesozoic rift basins that stretch from Nova Scotia to South Carolina. Rocks in the Newark Basin include Triassic through Jurassic-age sedimentary sequences of sandstones and shales that were intruded by diabase. Mineral deposits of hydrothermal origin are associated with alteration zones bordering intrusions of diabase and also occur as strata-bound replacement deposits of copper and zinc in sedimentary rocks. The USGS review of data available in 2003 showed that water from about 10 percent of wells throughout the Newark Basin of southeastern Pennsylvania had concentrations of arsenic greater than the USEPA maximum contaminant level (MCL) of 10 ?g/L; the highest reported arsenic concentration was at about 70 ?g/L. Few data on boron were available, and the highest reported boron concentration in well-water samples was 60 ?g/L in contrast

  7. Thermodynamic stability and properties of boron subnitrides from first principles

    NASA Astrophysics Data System (ADS)

    Ektarawong, A.; Simak, S. I.; Alling, B.

    2017-02-01

    We use the first-principles approach to clarify the thermodynamic stability as a function of pressure and temperature of three different α -rhombohedral-boron-like boron subnitrides, with the compositions of B6N , B13N2 , and B38N6 , proposed in the literature. We find that, out of these subnitrides with the structural units of B12(N-N), B12(NBN), and [B12(N-N) ] 0.33[B12(NBN)] 0.67 , respectively, only B38N6 , represented by [B12(N-N) ] 0.33[B12(NBN)] 0.67 , is thermodynamically stable. Beyond a pressure of about 7.5 GPa depending on the temperature, also B38N6 becomes unstable, and decomposes into cubic boron nitride and α -tetragonal-boron-like boron subnitride B50N2 . The thermodynamic stability of boron subnitrides and relevant competing phases is determined by the Gibbs free energy, in which the contributions from the lattice vibrations and the configurational disorder are obtained within the quasiharmonic and the mean-field approximations, respectively. We calculate lattice parameters, elastic constants, phonon and electronic density of states, and demonstrate that [B12(N-N) ] 0.33[B12(NBN)] 0.67 is both mechanically and dynamically stable, and is an electrical semiconductor. The simulated x-ray powder-diffraction pattern as well as the calculated lattice parameters of [B12(N-N) ] 0.33[B12(NBN)] 0.67 are found to be in good agreement with those of the experimentally synthesized boron subnitrides reported in the literature, verifying that B38N6 is the stable composition of α -rhombohedral-boron-like boron subnitride.

  8. Boron-Based Hydrogen Storage: Ternary Borides and Beyond

    SciTech Connect

    Vajo, John J.

    2016-04-28

    DOE continues to seek reversible solid-state hydrogen materials with hydrogen densities of ≥11 wt% and ≥80 g/L that can deliver hydrogen and be recharged at moderate temperatures (≤100 °C) and pressures (≤100 bar) enabling incorporation into hydrogen storage systems suitable for transportation applications. Boron-based hydrogen storage materials have the potential to meet the density requirements given boron’s low atomic weight, high chemical valance, and versatile chemistry. However, the rates of hydrogen exchange in boron-based compounds are thus far much too slow for practical applications. Although contributing to the high hydrogen densities, the high valance of boron also leads to slow rates of hydrogen exchange due to extensive boron-boron atom rearrangements during hydrogen cycling. This rearrangement often leads to multiple solid phases occurring over hydrogen release and recharge cycles. These phases must nucleate and react with each other across solid-solid phase boundaries leading to energy barriers that slow the rates of hydrogen exchange. This project sought to overcome the slow rates of hydrogen exchange in boron-based hydrogen storage materials by minimizing the number of solid phases and the boron atom rearrangement over a hydrogen release and recharge cycle. Two novel approaches were explored: 1) developing matched pairs of ternary borides and mixed-metal borohydrides that could exchange hydrogen with only one hydrogenated phase (the mixed-metal borohydride) and only one dehydrogenated phase (the ternary boride); and 2) developing boranes that could release hydrogen by being lithiated using lithium hydride with no boron-boron atom rearrangement.

  9. Automatic Construction of Hierarchical Road Networks

    NASA Astrophysics Data System (ADS)

    Yang, Weiping

    2016-06-01

    This paper describes an automated method of constructing a hierarchical road network given a single dataset, without the presence of thematic attributes. The method is based on a pattern graph which maintains nodes and paths as junctions and through-traffic roads. The hierarchy is formed incrementally in a top-down fashion for highways, ramps, and major roads directly connected to ramps; and bottom-up for the rest of major and minor roads. Through reasoning and analysis, ramps are identified as unique characteristics for recognizing and assembling high speed roads. The method makes distinctions on the types of ramps by articulating their connection patterns with highways. Major and minor roads will be identified by both quantitative and qualitative analysis of spatial properties and by discovering neighbourhood patterns revealed in the data. The result of the method would enrich data description and support comprehensive queries on sorted exit or entry points on highways and their related roads. The enrichment on road network data is important to a high successful rate of feature matching for road networks and to geospatial data integration.

  10. 23. Road view at Jim Camp Wash. Note Rainbow Museum ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    23. Road view at Jim Camp Wash. Note Rainbow Museum at rear. Road is on east-west axis here as original design of Rainbow Museum area. Long Logs Road to left foreground. Park Road to right foreground. Looking W. - Petrified Forest National Park Roads & Bridges, Holbrook, Navajo County, AZ

  11. Road Network Generalization Based on Float CAR Tracking

    NASA Astrophysics Data System (ADS)

    Zhou, Cheng; Li, Wenjing; Jia, Hongguo

    2016-06-01

    Road generalization is not only helpful to simplify complicated road networks but can also satisfy the needs of reasonable display of roads under varying scales, thus offering basis for updating and grading urban roads. This paper proposes a selection method for road network generalization by integrating road-associated vehicle trajectory dynamic properties and road features and calculating the importance of urban roads. First of all, the location and motion information of floating vehicles are associated to relevant roads to generate the dynamic properties of roads. Then, the dynamic and static properties of roads are analyzed, and the cluster analysis is conducted to the trajectory points at road intersections to obtain the importance of some road intersections there are vehicles passing by. Afterwards, the weights of roads are calculated using the dominance rough set, the roads are ranked by weight and the practical significance of ranking results is analyzed. Finally, the selection rules for the basic framework of road network are determined to meet with different requirements and guarantee both connectivity and completeness of road networks. The results show that the relative importance of roads is made clear by taking advantage of the rough set and the generalized road network highlights the distribution and connection of urban main roads.

  12. Dispersion corrections in the boron buckyball and nanotubes

    NASA Astrophysics Data System (ADS)

    Gunasinghe, Rosi N.; Kah, Cherno B.; Quarles, Kregg D.; Wang, Xiao-Qian

    2011-06-01

    We have investigated structural and electronic properties of the B80 buckyball and boron nanotubes by means of dispersion-corrected density-functional calculations. Our analysis reveals the vibrational stability for the icosahedral B80 with the inclusion of dispersion corrections, in contrast to the instability to a tetrahedral B80 with puckered capping atoms from preceding density-functional theory calculations. Similarly, the dispersion-corrected density-functional calculations yield non-puckered boron nanotube conformations and an associated metallic state for zigzag tubes. Our study indicates that the incorporation of long-range dispersive interactions is particularly important to the structural and electronic properties of boron fullerenes and nanotubes.

  13. Defects involving interstitial boron in low-temperature irradiated silicon

    NASA Astrophysics Data System (ADS)

    Khirunenko, L. I.; Sosnin, M. G.; Duvanskii, A. V.; Abrosimov, N. V.; Riemann, H.

    2016-12-01

    Interstitial boron-related defects in silicon subjected to irradiation with 5 MeV electrons at a temperature of 80 K are investigated by Fourier-transform infrared absorption spectroscopy. This study demonstrates the radiation-enhanced annealing of interstitial boron during irradiation. We have revealed the interaction, which occurs in the course of irradiation, of diffusing interstitial boron atoms with one another and with interstitial oxygen. The local vibrational modes associated with these defects are identified, and the thermal stability of the defects is determined.

  14. Synthesis of aluminium nitride/boron nitride composite materials

    SciTech Connect

    Xiao, T.D. . Polymer Science Program and Dept. of Chemistry); Gonsalves, K.E. . Polymer Science Program and Dept. of Chemistry Univ. of Connecticut, Storrs, CT . Dept. of Chemistry); Strutt, P.R. . Dept. of Metallurgy)

    1993-04-01

    Aluminum nitride/boron nitride composite was synthesized by using boric acid, urea, and aluminum chloride (or aluminum lactate) as the starting compounds. The starting materials were dissolved in water and mixed homogeneously. Ammonolysis of this aqueous solution resulted in the formation of a precomposite gel, which converted into the aluminum nitride/boron nitride composite on further heat treatment. Characterization of both the precomposite and the composite powders included powder X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy. Analysis of the composite revealed that the aluminum nitride phase had a hexagonal structure, and the boron nitride phase a turbostratic structure.

  15. Hugoniot equation of state and dynamic strength of boron carbide

    SciTech Connect

    Grady, Dennis E.

    2015-04-28

    Boron carbide ceramics have been particularly problematic in attempts to develop adequate constitutive model descriptions for purposes of analysis of dynamic response in the shock and impact environment. Dynamic strength properties of boron carbide ceramic differ uniquely from comparable ceramics. Furthermore, boron carbide is suspected, but not definitely shown, to undergoing polymorphic phase transformation under shock compression. In the present paper, shock-wave compression measurements conducted over the past 40 years are assessed for the purpose of achieving improved understanding of the dynamic equation of state and strength of boron carbide. In particular, attention is focused on the often ignored Los Alamos National Laboratory (LANL) Hugoniot measurements performed on porous sintered boron carbide ceramic. The LANL data are shown to exhibit two compression anomalies on the shock Hugoniot within the range of 20–60 GPa that may relate to crystallographic structure transitions. More recent molecular dynamics simulations on the compressibility of the boron carbide crystal lattice reveal compression transitions that bear similarities to the LANL Hugoniot results. The same Hugoniot data are complemented with dynamic isentropic compression data for boron carbide extracted from Hugoniot measurements on boron carbide and copper granular mixtures. Other Hugoniot measurements, however, performed on near-full-density boron carbide ceramic differ markedly from the LANL Hugoniot data. These later data exhibit markedly less compressibility and tend not to show comparable anomalies in compressibility. Alternative Hugoniot anomalies, however, are exhibited by the near-full-density data. Experimental uncertainty, Hugoniot strength, and phase transformation physics are all possible explanations for the observed discrepancies. It is reasoned that experimental uncertainty and Hugoniot strength are not likely explanations for the observed differences. The notable

  16. Process for producing wurtzitic or cubic boron nitride

    DOEpatents

    Holt, J. Birch; Kingman, deceased, Donald D.; Bianchini, Gregory M.

    1992-01-01

    Disclosed is a process for producing wurtzitic or cubic boron nitride comprising the steps of: [A] preparing an intimate mixture of powdered boron oxide, a powdered metal selected from the group consisting of magnesium or aluminum, and a powdered metal azide; [B] igniting the mixture and bringing it to a temperature at which self-sustaining combustion occurs; [C] shocking the mixture at the end of the combustion thereof with a high pressure wave, thereby forming as a reaction product, wurtzitic or cubic boron nitride and occluded metal oxide; and, optionally [D] removing the occluded metal oxide from the reaction product. Also disclosed are reaction products made by the process described.

  17. Process for producing wurtzitic or cubic boron nitride

    DOEpatents

    Holt, J.B.; Kingman, D.D.; Bianchini, G.M.

    1992-04-28

    Disclosed is a process for producing wurtzitic or cubic boron nitride comprising the steps of: [A] preparing an intimate mixture of powdered boron oxide, a powdered metal selected from the group consisting of magnesium or aluminum, and a powdered metal azide; [B] igniting the mixture and bringing it to a temperature at which self-sustaining combustion occurs; [C] shocking the mixture at the end of the combustion thereof with a high pressure wave, thereby forming as a reaction product, wurtzitic or cubic boron nitride and occluded metal oxide; and, optionally [D] removing the occluded metal oxide from the reaction product. Also disclosed are reaction products made by the process described.

  18. Modeling boron diffusion gettering of iron in silicon solar cells

    NASA Astrophysics Data System (ADS)

    Haarahiltunen, A.; Talvitie, H.; Savin, H.; Yli-Koski, M.; Asghar, M. I.; Sinkkonen, J.

    2008-01-01

    In this paper, a model is presented for boron diffusion gettering of iron in silicon during thermal processing. In the model, both the segregation of iron due to high boron doping concentration and heterogeneous precipitation of iron to the surface of the wafer are taken into account. It is shown, by comparing simulated results with experimental ones, that this model can be used to estimate boron diffusion gettering efficiency of iron under a variety of processing conditions. Finally, the application of the model to phosphorus diffusion gettering is discussed.

  19. An introduction to boron: history, sources, uses, and chemistry.

    PubMed Central

    Woods, W G

    1994-01-01

    Following a brief overview of the terrestrial distribution of boron in rocks, soil, and water, the history of the discovery, early utilization, and geologic origin of borate minerals is summarized. Modern uses of borate-mineral concentrates, borax, boric acid, and other refined products include glass, fiberglass, washing products, alloys and metals, fertilizers, wood treatments, insecticides, and microbiocides. The chemistry of boron is reviewed from the point of view of its possible health effects. It is concluded that boron probably is complexed with hydroxylated species in biologic systems, and that inhibition and stimulation of enzyme and coenzymes are pivotal in its mode of action. Images Figure 1. PMID:7889881

  20. [Boron neutron capture therapy (BNCT) as cancer treatment].

    PubMed

    Joensuu, Heikki; Kankaanranta, Leena; Tenhunen, Mikko; Saarilahti, Kauko

    2011-01-01

    Boron neutron capture therapy leads to a strong local radiotherapy effect. The efficacy of the method in cancer therapy requires sufficient accumulation of boron into and a fairly superficial location of the tumor. The efficacy and tolerability of this therapy has been investigated in Finland especially in locally recurring head and neck cancer. These tumors have responded favorably to boron neutron capture therapy and the treatment has been relatively well tolerated, although most cancers have recurred locally with few cases of durable complete remission.