WorldWideScience

Sample records for boron history sources

  1. Operation and Applications of the Boron Cathodic Arc Ion Source

    International Nuclear Information System (INIS)

    Williams, J. M.; Freeman, J. H.; Klepper, C. C.; Chivers, D. J.; Hazelton, R. C.

    2008-01-01

    The boron cathodic arc ion source has been developed with a view to several applications, particularly the problem of shallow junction doping in semiconductors. Research has included not only development and operation of the boron cathode, but other cathode materials as well. Applications have included a large deposition directed toward development of a neutron detector and another deposition for an orthopedic coating, as well as the shallow ion implantation function. Operational experience is described and information pertinent to commercial operation, extracted from these experiments, is presented.

  2. Boron

    Science.gov (United States)

    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...

  3. Multiple sources of boron in urban surface waters and groundwaters

    Energy Technology Data Exchange (ETDEWEB)

    Hasenmueller, Elizabeth A., E-mail: eahasenm@wustl.edu; Criss, Robert E.

    2013-03-01

    Previous studies attribute abnormal boron (B) levels in streams and groundwaters to wastewater and fertilizer inputs. This study shows that municipal drinking water used for lawn irrigation contributes substantial non-point loads of B and other chemicals (S-species, Li, and Cu) to surface waters and shallow groundwaters in the St. Louis, Missouri, area. Background levels and potential B sources were characterized by analysis of lawn and street runoff, streams, rivers, springs, local rainfall, wastewater influent and effluent, and fertilizers. Urban surface waters and groundwaters are highly enriched in B (to 250 μg/L) compared to background levels found in rain and pristine, carbonate-hosted streams and springs (< 25 μg/L), but have similar concentrations (150 to 259 μg/L) compared to municipal drinking waters derived from the Missouri River. Other data including B/SO{sub 4}{sup 2-}−S and B/Li ratios confirm major contributions from this source. Moreover, sequential samples of runoff collected during storms show that B concentrations decrease with increased discharge, proving that elevated B levels are not primarily derived from combined sewer overflows (CSOs) during flooding. Instead, non-point source B exhibits complex behavior depending on land use. In urban settings B is rapidly mobilized from lawns during “first flush” events, likely representing surficial salt residues from drinking water used to irrigate lawns, and is also associated with the baseflow fraction, likely derived from the shallow groundwater reservoir that over time accumulates B from drinking water that percolates into the subsurface. The opposite occurs in small rural watersheds, where B is leached from soils by recent rainfall and covaries with the event water fraction. Highlights: ► Boron sources and loads differ between urban and rural watersheds. ► Wastewaters are not the major boron source in small St. Louis, MO watersheds. ► Municipal drinking water used for lawn

  4. The effect of the boron source composition ratio on the adsorption performance of hexagonal boron nitride without a template

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ning, E-mail: zhangning5832@163.com; Zhang, Tong; Kan, Hongmin; Wang, Xiaoyang; Long, Haibo; Cui, Xingyu

    2015-08-01

    An inexpensive boric acid (H{sub 3}BO{sub 3}) and borax (Na{sub 2}B{sub 4}O{sub 7}·10H{sub 2}O) mix was used as a source of boron with different composition ratios, and urea was used as a nitrogen source, in flowing ammonia atmosphere, for the preparation of hexagonal boron nitride (h-BN) with different micro-morphologies. Under a certain synthesis process, the effects of the molar ratio of borax and boric acid (or simply the boron source composition ratio for short) on the phase composition of the sample were studied; the work also explored the effect of boron source composition ratio on the micro-morphology, adsorption desorption isotherm and specific surface area of the h-BN powder. The main purpose of this work was to determine the optimum composition ratio of preparing spherical mesoporous h-BN and ensure that the micro-mechanism underpinning the formation of spherical mesoporous h-BN was understood. The results showed that at the optimum boron source composition ratio of 1:1, globular mesoporous spheres with a diameter of approximately 600–800 nm could be obtained with the highest pore volume and specific surface area (230.2 m{sup 2}/g). - Graphical abstract: Display Omitted - Highlights: • Spherical h-BN was synthesized by controlling the boron source composition ratio. • Without extra spherical template, solid Na{sub 2}O was equal to a spherical template. • At boron source composition ratio of 1:1, h-BN had best adsorption performance.

  5. Preparation and electrical properties of boron and boron phosphide films obtained by gas source molecular beam deposition

    Energy Technology Data Exchange (ETDEWEB)

    Kumashiro, Y.; Yokoyama, T.; Sakamoto, T.; Fujita, T. [Yokohama National Univ. (Japan)

    1997-10-01

    Boron and boron phosphide films were prepared by gas source molecular beam deposition on sapphire crystal at various substrate temperatures up to 800{degrees}C using cracked B{sub 2}H{sub 6} (2% in H{sub 2}) at 300{degrees}C and cracked PH{sub 3} (20% in H{sub 2}) at 900{degrees}C. The substrate temperatures and gas flow rates of the reactant gases determined the film growth. The boron films with amorphous structure are p type. Increasing growth times lead to increasing mobilities and decreasing carrier concentrations. Boron phosphide film with maximum P/B ratio is obtained at a substrate temperature of 600{degrees}C, below and above which they become phosphorous deficient due to insufficient supply of phosphorus and thermal desorption of the phosphorus as P{sub 2}, respectively, but they are all n type conductors due to phosphorus vacancies.

  6. History Sources on the Internet.

    Science.gov (United States)

    Fink, Kenneth D.

    This paper provides descriptions of key online history resources useful to teachers, librarians, and other education professionals. Highlights include: primary sources on the Internet; archives; Online Public Access Catalogs (OPACs); the American Historical Association (AHA) Web site; state and federal government resources; business history…

  7. Sonochemical-assisted magnesium borate synthesis from different boron sources

    Directory of Open Access Journals (Sweden)

    Yildirim Meral

    2017-03-01

    Full Text Available In this study, sonochemical-assisted magnesium borate synthesis is studied from different boron sources. Various reaction parameters are successfully applied by a simple and green method. X-ray diffraction (XRD, Fourier transform infrared (FT-IR and Raman spectroscopies are used to characterize the synthesized magnesium borates on the other hand surface morphologies are investigated by using scanning electron microscope (SEM. The XRD analyses showed that the products were admontite [MgO(B2O33 · 7(H2O] with JCPDS (Joint Committee on Powder Diffraction Standards no. of 01-076-0540 and mcallisterite [Mg2(B6O7(OH62 · 9(H2O] with JCPDS no. of 01-070-1902. The results that found in the spectroscopic studies were in a good agreement with characteristic magnesium borate bands in both regions of infra-red and visible. According to SEM results, obtained borates were in micro and sub-micro scales. By the use of ultrasonication, reaction yields were found between 84.2 and 97.9%. As a result, it is concluded that the sonochemical approach is a practicable synthesis method to get high efficiency and high crystallinity in the synthesis magnesium borate compounds.

  8. Lateral boron distribution in polycrystalline SiC source materials

    DEFF Research Database (Denmark)

    Linnarsson, M. K.; Kaiser, M.; Liljedahl, R.

    2013-01-01

    . The materials are co-doped materials with nitrogen and boron to a concentration of 1x1018 cm-3 and 1x1019 cm-3, respectively. Depth profiles as well as ion images have been recorded. According to ocular inspection, the analyzed poly-SiC consists mainly of 4H-SiC and 6H-SiC grains. In these grains, the boron...

  9. Determination of boron in water solution by an indirect neutron activation technique from a 241Am/Be source

    International Nuclear Information System (INIS)

    Sales, H.B.

    1981-08-01

    Boron content in water solutions has been analysed by Indirect Activation Technique a twin 241 Am/Be neutron source with a source strength of 9x10 6 n/seg. The boron concentration was inferred from the measurement of the activity induced in a vanadium flux monitor. The vanadium rod was located inside the boron solution in a standart geometrical set up with respect to the neutron source. Boron concentrations in the range of 100 to 1000 ppm were determined with an overall accuracy of about 2% during a total analysis time of about 20 minutes. Eventhough the analysis is not selective for boron yet due the rapid, simple and precise nature, it is proposed for the analysis of boron in the primary coolant circuit of Nuclear Power Plants of PWR type. (Author) [pt

  10. Source of boron in the Palokas gold deposit, northern Finland: evidence from boron isotopes and major element composition of tourmaline

    Science.gov (United States)

    Ranta, Jukka-Pekka; Hanski, Eero; Cook, Nick; Lahaye, Yann

    2017-06-01

    The recently discovered Palokas gold deposit is part of the larger Rompas-Rajapalot gold-mineralized system located in the Paleoproterozoic Peräpohja Belt, northern Finland. Tourmaline is an important gangue mineral in the Palokas gold mineralization. It occurs as tourmalinite veins and as tourmaline crystals in sulfide-rich metasomatized gold-bearing rocks. In order to understand the origin of tourmaline in the gold-mineralized rocks, we have investigated the major element chemistry and boron isotope composition of tourmaline from three areas: (1) the Palokas gold mineralization, (2) a pegmatitic tourmaline granite, and (3) the evaporitic Petäjäskoski Formation. Based on textural evidence, tourmaline in gold mineralization is divided into two different types. Type 1 is located within the host rock and is cut by rock-forming anthophyllite crystals. Type 2 occurs in late veins and/or breccia zones consisting of approximately 80% tourmaline and 20% sulfides, commonly adjacent to quartz veins. All the studied tourmaline samples belong to the alkali-group tourmaline and can be classified as dravite and schorl. The δ11B values of the three localities lie in the same range, from 0 to -4‰. Tourmaline from the Au mineralization and from the Petäjäskoski Formation has similar compositional trends. Mg is the major substituent for Al; inferred low Fe3+/Fe2+ ratios and Na values (molybdenite related to the tourmaline-sulfide-quartz veins, we propose that the tourmaline-forming process is a result of a single magmatic-hydrothermal event related to the extensive granite magmatism at around 1.79-1.77 Ga. Tourmaline was crystallized throughout the hydrothermal process, which resulted in the paragenetic variation between type 1 and type 2. The close association of tourmaline and gold suggests that the gold precipitated from the same boron-rich source as tourmaline.

  11. An accelerator-based epithermal photoneutron source for boron neutron capture therapy

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, Hannah E. [Georgia Inst. of Technology, Atlanta, GA (United States)

    1996-04-01

    Boron neutron capture therapy is an experimental binary cancer radiotherapy modality in which a boronated pharmaceutical that preferentially accumulates in malignant tissue is first administered, followed by exposing the tissue in the treatment volume to a thermal neutron field. Current usable beams are reactor-based but a viable alternative is the production of an epithermal neutron beam from an accelerator. Current literature cites various proposed accelerator-based designs, most of which are based on proton beams with beryllium or lithium targets. This dissertation examines the efficacy of a novel approach to BNCT treatments that incorporates an electron linear accelerator in the production of a photoneutron source. This source may help to resolve some of the present concerns associated with accelerator sources, including that of target cooling. The photoneutron production process is discussed as a possible alternate source of neutrons for eventual BNCT treatments for cancer. A conceptual design to produce epithermal photoneutrons by high photons (due to bremsstrahlung) impinging on deuterium targets is presented along with computational and experimental neutron production data. A clinically acceptable filtered epithermal neutron flux on the order of 107 neutrons per second per milliampere of electron current is shown to be obtainable. Additionally, the neutron beam is modified and characterized for BNCT applications by employing two unique moderating materials (an Al/AlF3 composite and a stacked Al/Teflon design) at various incident electron energies.

  12. An accelerator-based epithermal photoneutron source for boron neutron capture therapy

    International Nuclear Information System (INIS)

    Mitchell, H.E.

    1996-04-01

    Boron neutron capture therapy is an experimental binary cancer radiotherapy modality in which a boronated pharmaceutical that preferentially accumulates in malignant tissue is first administered, followed by exposing the tissue in the treatment volume to a thermal neutron field. Current usable beams are reactor-based but a viable alternative is the production of an epithermal neutron beam from an accelerator. Current literature cites various proposed accelerator-based designs, most of which are based on proton beams with beryllium or lithium targets. This dissertation examines the efficacy of a novel approach to BNCT treatments that incorporates an electron linear accelerator in the production of a photoneutron source. This source may help to resolve some of the present concerns associated with accelerator sources, including that of target cooling. The photoneutron production process is discussed as a possible alternate source of neutrons for eventual BNCT treatments for cancer. A conceptual design to produce epithermal photoneutrons by high photons (due to bremsstrahlung) impinging on deuterium targets is presented along with computational and experimental neutron production data. A clinically acceptable filtered epithermal neutron flux on the order of 10 7 neutrons per second per milliampere of electron current is shown to be obtainable. Additionally, the neutron beam is modified and characterized for BNCT applications by employing two unique moderating materials (an Al/AlF 3 composite and a stacked Al/Teflon design) at various incident electron energies

  13. Optimal Neutron Source and Beam Shaping Assembly for Boron Neutron Capture Therapy

    International Nuclear Information System (INIS)

    Vujic, J.; Greenspan, E.; Kastenber, W.E.; Karni, Y.; Regev, D.; Verbeke, J.M.; Leung, K.N.; Chivers, D.; Guess, S.; Kim, L.; Waldron, W.; Zhu, Y.

    2003-01-01

    There were three objectives to this project: (1) The development of the 2-D Swan code for the optimization of the nuclear design of facilities for medical applications of radiation, radiation shields, blankets of accelerator-driven systems, fusion facilities, etc. (2) Identification of the maximum beam quality that can be obtained for Boron Neutron Capture Therapy (BNCT) from different reactor-, and accelerator-based neutron sources. The optimal beam-shaping assembly (BSA) design for each neutron source was also to e obtained. (3) Feasibility assessment of a new neutron source for NCT and other medical and industrial applications. This source consists of a state-of-the-art proton or deuteron accelerator driving and inherently safe, proliferation resistant, small subcritical fission assembly

  14. A shielding design for an accelerator-based neutron source for boron neutron capture therapy

    Energy Technology Data Exchange (ETDEWEB)

    Hawk, A.E.; Blue, T.E. E-mail: blue.1@osu.edu; Woollard, J.E

    2004-11-01

    Research in boron neutron capture therapy (BNCT) at The Ohio State University Nuclear Engineering Department has been primarily focused on delivering a high quality neutron field for use in BNCT using an accelerator-based neutron source (ABNS). An ABNS for BNCT is composed of a proton accelerator, a high-energy beam transport system, a {sup 7}Li target, a target heat removal system (HRS), a moderator assembly, and a treatment room. The intent of this paper is to demonstrate the advantages of a shielded moderator assembly design, in terms of material requirements necessary to adequately protect radiation personnel located outside a treatment room for BNCT, over an unshielded moderator assembly design.

  15. Boron-Containing Red Light-Emitting Phosphors And Light Sources Incorporating The Same

    Science.gov (United States)

    Srivastava, Alok Mani; Comanzo, Holly Ann; Manivannan, Venkatesan

    2006-03-28

    A boron-containing phosphor comprises a material having a formula of AD1-xEuxB9O16, wherein A is an element selected from the group consisting of Ba, Sr, Ca, Mg, and combinations thereof; D is at least an element selected from the group consisting of rare-earth metals other than europium; and x is in the range from about 0.005 to about 0.5. The phosphor is used in a blend with other phosphors in a light source for generating visible light with a high color rendering index.

  16. Study on high speed lithium jet for neutron source of boron neutron capture therapy (BNCT)

    International Nuclear Information System (INIS)

    Takahashi, Minoru; Kobayashi, Tooru; Zhang, Mingguang; Mak, Michael; Stefanica, Jiri; Dostal, Vaclav; Zhao Wei

    2012-01-01

    The feasibility study of a liquid lithium type proton beam target was performed for the neutron source of the boron neutron capture therapy (BNCT). As the candidates of the liquid lithium target, a thin sheet jet and a thin film flow on a concave wall were chosen, and a lithium flow experiment was conducted to investigate the hydrodynamic stability of the targets. The surfaces of the jets and film flows with a thickness of 0.5 mm and a width of 50 mm were observed by means of photography. It has been found that a stable sheet jet and a stable film flow on a concave wall can be formed up to certain velocities by using a straight nozzle and a curved nozzle with the concave wall, respectively. (author)

  17. Eyewitness Culture and History: Primary Written Sources. The Iconoclast.

    Science.gov (United States)

    McMurtry, John

    1995-01-01

    Asserts that contemporary history and historiography is "official" history that ignores the daily struggles of people for their continued survival. Argues that, while public illiteracy has nearly disappeared, individuals are ignorant of the wealth of primary-source materials of other cultures' histories. (CFR)

  18. Accelerator-based epithermal neutron sources for boron neutron capture therapy of brain tumors.

    Science.gov (United States)

    Blue, Thomas E; Yanch, Jacquelyn C

    2003-01-01

    This paper reviews the development of low-energy light ion accelerator-based neutron sources (ABNSs) for the treatment of brain tumors through an intact scalp and skull using boron neutron capture therapy (BNCT). A major advantage of an ABNS for BNCT over reactor-based neutron sources is the potential for siting within a hospital. Consequently, light-ion accelerators that are injectors to larger machines in high-energy physics facilities are not considered. An ABNS for BNCT is composed of: (1) the accelerator hardware for producing a high current charged particle beam, (2) an appropriate neutron-producing target and target heat removal system (HRS), and (3) a moderator/reflector assembly to render the flux energy spectrum of neutrons produced in the target suitable for patient irradiation. As a consequence of the efforts of researchers throughout the world, progress has been made on the design, manufacture, and testing of these three major components. Although an ABNS facility has not yet been built that has optimally assembled these three components, the feasibility of clinically useful ABNSs has been clearly established. Both electrostatic and radio frequency linear accelerators of reasonable cost (approximately 1.5 M dollars) appear to be capable of producing charged particle beams, with combinations of accelerated particle energy (a few MeV) and beam currents (approximately 10 mA) that are suitable for a hospital-based ABNS for BNCT. The specific accelerator performance requirements depend upon the charged particle reaction by which neutrons are produced in the target and the clinical requirements for neutron field quality and intensity. The accelerator performance requirements are more demanding for beryllium than for lithium as a target. However, beryllium targets are more easily cooled. The accelerator performance requirements are also more demanding for greater neutron field quality and intensity. Target HRSs that are based on submerged-jet impingement and

  19. Determination of boron isotope ratios by high-resolution continuum source molecular absorption spectrometry using graphite furnace vaporizers

    Science.gov (United States)

    Abad, Carlos; Florek, Stefan; Becker-Ross, Helmut; Huang, Mao-Dong; Heinrich, Hans-Joachim; Recknagel, Sebastian; Vogl, Jochen; Jakubowski, Norbert; Panne, Ulrich

    2017-10-01

    Boron isotope amount ratios n(10B)/n(11B) have been determined by monitoring the absorption spectrum of boron monohydride (BH) in a graphite furnace using high-resolution continuum source molecular absorption spectrometry (HR-CS-MAS). Bands (0 → 0) and (1 → 1) for the electronic transition X1Σ+ → A1Π were evaluated around wavelengths 433.1 nm and 437.1 nm respectively. Clean and free of memory effect molecular spectra of BH were recorded. In order to eliminate the memory effect of boron, a combination of 2% (v/v) hydrogen gas in argon and 1% trifluoromethane in argon, an acid solution of calcium chloride and mannitol as chemical modifiers was used. Partial least square regression (PLS) for analysis of samples and reference materials were applied. For this, a spectral library with different isotopes ratios for PLS regression was built. Results obtained around the 433.1 nm and 437.1 nm spectral regions are metrologically compatible with those reported by mass spectrometric methods. Moreover, for the evaluated region of 437 nm, an accuracy of 0.15‰ is obtained as the average deviation from the isotope reference materials. Expanded uncertainties with a coverage factor of k = 2 range between 0.15 and 0.44‰. This accuracy and precision are compatible with those obtained by mass spectrometry for boron isotope ratio measurements.

  20. Phrasing history : Selecting sources in digital repositories

    NARCIS (Netherlands)

    Huistra, Hieke; Mellink, Bram

    2016-01-01

    In recent years, mass digitization has opened up voluminous text corpora to human interpretation. Full-text search lets historians now find new sources that can change their understanding of thoroughly studied historical episodes. At the same time, it forces scholars to access historical sources in

  1. Phrasing history: Selecting sources in digital repositories

    NARCIS (Netherlands)

    Huistra, H.; Mellink, B.

    2016-01-01

    In recent years, mass digitization has opened up voluminous text corpora to human interpretation. Full-text search lets historians now find new sources that can change their understanding of thoroughly studied historical episodes. At the same time, it forces scholars to access historical sources in

  2. MOCVD of hexagonal boron nitride thin films on Si(100) using new single source precursors

    CERN Document Server

    Boo, J H; Yu, K S; Kim, Y S; Kim, Y S; Park, J T

    1999-01-01

    We have been carried out the growth of hexagonal boron nitride (h-BN) thin films on Si(100) substrates by low pressure metal-organic chemical vapor deposition (LPMOCVD) method using triethylborane tert-butylamine complex (TEBTBA), Et sub 3 BNH sub 2 ( sup t Bu), and triethylborane isopropylamine complex (TEBIPA), Et sub 3 BNH sub 2 ( sup t Pr) as a new single molecular precursors in the temperature range of 850 approx 1000 .deg. C. polycrystalline, crack-free h-BN film was successfully grown on Si(100) substrate at 850 .deg. C using TEBTBA. This growth temperature is very lower than those in previous reports. Carbon-rich polycrystalline BN was also obtained at 900 .deg. C from TEBIPA. With increasing substrate temperature to 1000 .deg. C, however, BC sub 4 N-like species are strongly formed along with h-BN and the BN films obtained from both TEBTBA and TEBIPA but almost polycrystalline. To our best knowledge, this is the first report of the growth of h-BN films formed with the new single source precursors of ...

  3. The History of Cartographic Sources Development

    Directory of Open Access Journals (Sweden)

    L. Volkotrub

    2016-07-01

    Full Text Available Cartographic sources are the variety of descriptive sources. They include historical and geographical maps and circuits maps. The image maps are a special kind of modeling the real phenomenon, that broadcasts their quantitative and qualitative characteristics, structure, interconnections and dynamic in a graphic form. The prototypes of maps appeared as a way of transmitting information around the world. People began to use this way of communication long before the appearance of writing. The quality of mapping images matched with the evolution of techniques and methods of mapping and publishing. The general development of cartographic sources is determined primarily by three factors: the development of science and technology, the needs of society in different cartographic works, political and economic situation of country. Given this, map is an all-sufficient phenomenon, its sources expert study is based on understanding of invariance of its perception. Modern theoretical concepts show us the invariance of maps. Specifially, map is viewed in the following aspects: 1 it is one of the universal models of land and existing natural and social processes.2 it is one of the tools of researching and forecasting. 3 it is a specific language formation. 4 it is a method of transferring information. As a source map may contain important information about physical geography, geology, hydrology, political-administrative division, population, flora and fauna of a particular area in a particular period. Mostly, cartographic sources are complex, because they contain a lot of cognitive and historical information.

  4. Bring History Alive with Primary Sources

    Science.gov (United States)

    Lehman, Kathy

    2010-01-01

    Using primary sources such as a photograph from the Library of Congress American Memory collection engages learners to think about the past and relate it to their life today. Some artifacts come with an explanation, while some do not. These require critical thinking and investigation to locate information and hypothesize answers to questions posed…

  5. Oral Sources and Missionary Historiography in Igbo Church History ...

    African Journals Online (AJOL)

    The paper takes a look at the problems of oral sources and missionary historiography in Igbo church history, 1940-2012. Findings show that the problems of missionary and African Christian oral informants and historiographers had significant effect on Igbo church history. Primary and secondary means in the collection of ...

  6. Research of accelerator-based neutron source for boron neutron capture therapy

    International Nuclear Information System (INIS)

    Li Changkai; Ma Yingjie; Tang Xiaobin; Xie Qin; Geng Changran; Chen Da

    2013-01-01

    Background: 7 Li (p, n) reaction of high neutron yield and low threshold energy has become one of the most important neutron generating reactions for Accelerator-based Boron Neutron Capture Therapy (BNCT). Purpose Focuses on neutron yield and spectrum characteristics of this kind of neutron generating reaction which serves as an accelerator-based neutron source and moderates the high energy neutron beams to meet BNCT requirements. Methods: The yield and energy spectrum of neutrons generated by accelerator-based 7 Li(p, n) reaction with incident proton energy from 1.9 MeV to 3.0 MeV are researched using the Monte Carlo code-MCNPX2.5.0. And the energy and angular distribution of differential neutron yield by 2.5-MeV incident proton are also given in this part. In the following part, the character of epithermal neutron beam generated by 2.5-MeV incident protons is moderated by a new-designed moderator. Results: Energy spectra of neutrons generated by accelerator-based 7 Li(p, n) reaction with incident proton energy from 1.9 MeV to 3.0 MeV are got through the simulation and calculation. The best moderator thickness is got through comparison. Conclusions: Neutron beam produced by accelerator-based 7 Li(p, n) reaction, with the bombarding beam of 10 mA and the energy of 2.5 MeV, can meet the requirement of BNCT well after being moderated. (authors)

  7. The comparison of four neutron sources for Prompt Gamma Neutron Activation Analysis (PGNAA) in vivo detections of boron.

    Science.gov (United States)

    Fantidis, J G; Nicolaou, G E; Potolias, C; Vordos, N; Bandekas, D V

    A Prompt Gamma Ray Neutron Activation Analysis (PGNAA) system, incorporating an isotopic neutron source has been simulated using the MCNPX Monte Carlo code. In order to improve the signal to noise ratio different collimators and a filter were placed between the neutron source and the object. The effect of the positioning of the neutron beam and the detector relative to the object has been studied. In this work the optimisation procedure is demonstrated for boron. Monte Carlo calculations were carried out to compare the performance of the proposed PGNAA system using four different neutron sources ( 241 Am/Be, 252 Cf, 241 Am/B, and DT neutron generator). Among the different systems the 252 Cf neutron based PGNAA system has the best performance.

  8. Annual Reports: Preserving and Disseminating a Source for Business History

    Science.gov (United States)

    Cronin-Kardon, Cynthia L.; Halperin, Michael

    2007-01-01

    Lippincott Library's Historical Corporate Annual Reports Collection contains useful primary sources of information for several disciplines, including applied accounting and business history. They also are reflections of the societal and cultural mores of the times. Unfortunately, these reports are fragile, difficult to locate, and hard to access.…

  9. Determining Source Attenuation History to Support Closure by Natural Attenuation

    Science.gov (United States)

    2013-11-01

    restrictive and not very representative • Passes “ eyeball test” for style Source history captures the style of measured field data: Ratio of... eyeball test.” For all of the cases, the simulated and measured soil data often appeared very similar in style throughout the entire low permeability...representative metric confirmed that the modeling results demonstrated reasonable accuracy, which matches the expectations based on simple “ eyeball

  10. Dosimetry boron neutron capture therapy in liver cancer (hepatocellular carcinoma) by means of MCNP-code with neutron source from thermal column

    International Nuclear Information System (INIS)

    Irhas; Andang Widi Harto; Yohannes Sardjono

    2014-01-01

    Boron Neutron Capture Therapy (BNCT) using physics principle when B 10 (Boron-10) irradiated by low energy neutron (thermal neutron). Boron and thermal neutron reaction produced B 11m (Boron-11m) (t 1/2 =10 -2 s). B 11m decay emitted alpha, Li 7 (Lithium-7) particle and gamma ray. Irradiated time needed to ensure cancer dose enough. Liver cancer was primary malignant who located in liver (Hepatocellular carcinoma). Malignant in liver were different to metastatic from Breast, Colon Cancer, and the other. This condition was Metastatic Liver Cancer. Monte Carlo method used by Monte Carlo N-Particle (MCNP) Software. Probabilistic approach used for probability of interaction occurred and record refers to characteristic of particle and material. In this case, thermal neutron produced by model of Collimated Thermal Column Kartini Research Nuclear Reactor, Yogyakarta. Modelling organ and source used liver organ that contain of cancer tissue and research reactor. Variation of boron concentration was 20, 25, 30, 35, 40, 45, and 47 µg/g cancers. Output of MCNP calculation were neutron scattering dose, gamma ray dose and neutron flux from reactor. Neutron flux used to calculate alpha, proton and gamma ray dose from interaction of tissue material and thermal neutron. Variation of boron concentration result dose rate to every variation were 0,059; 0,072; 0,084; 0,098; 0.108; 0,12; 0,125 Gy/sec. Irradiation time who need to every concentration were 841,5 see (14 min 1 sec); 696,07 sec(11 min 36 sec); 593.11 sec (9 min 53 sec); 461,35 sec (8 min 30 sec); 461,238 sec (7 min 41 sec); 414,23 sec (6 min 54 sec); 398,38 sec (6 min 38 sec). Irradiating time could shortly when boron concentration more high. (author)

  11. Evaluation of moderator assemblies for use in an accelerator-based neutron source for boron neutron capture therapy

    International Nuclear Information System (INIS)

    Woollard, J.E.; Blue, T.E.; Gupta, N.; Gahbauer, R.A.

    1998-01-01

    The neutron fields produced by several moderator assemblies were evaluated using both in-phantom and in-air neutron field assessment parameters. The parameters were used to determine the best moderator assembly, from among those evaluated, for use in the accelerator-based neutron source for boron neutron capture therapy. For a 10-mA proton beam current and the specified treatment parameters, a moderator assembly consisting of a BeO moderator and a Li 2 CO 3 reflector was found to be the best moderator assembly whether the comparison was based on in-phantom or in-air neutron field assessment parameters. However, the parameters were discordant regarding the moderator thickness. The in-phantom neutron field assessment parameters predict 20 cm of BeO as the best moderator thickness, whereas the in-air neutron field assessment parameters predict 25 cm of BeO as the best moderator thickness

  12. The effect of thermal history on intergranular boron segregation and fracture morphology of substoichiometric Ni3Al

    International Nuclear Information System (INIS)

    Choudhury, A.; White, C.L.; Brooks, C.R.

    1986-01-01

    While it has attractive mechanical properties and good corrosion resistance, the usefulness of polycrystalline Ni 3 Al has been restricted because of its propensity for brittle intergranular fracture. While this intergranular brittleness can be aggravated by the intergranular segregation of certain impurities, particularly sulfur, the grain boundaries of Ni 3 Al are intrinsically brittle and Ni 3 Al will fail intergranularly in the absence of detectable impurity segregation. Addition of boron resulted in the fracture morphology changing from primarily intergranular to largely transgranular; and more importantly, the intergranular segregation of boron was conclusively demonstrated. The range of boron concentrations over which these beneficial effects are observed is well within the solubility limit, which has been estimated to be 1.5 at. % (4,5). Rice (6) developed a relationship between equilibrium intergranular segregation and grain boundary cohesion. According to this theory, the potential for intergranular embrittlement by a solute is related to the relative intensity of segregation of the solute to free surfaces as compared to segregation to grain boundaries. Rices theory allowed for the case of a solute segregating more strongly to grain boundaries than to free surfaces. If this difference is sufficiently large (approximately a factor of two), Rice's theory predicts an enhancement of grain boudary cohesion. White and coworkers (4,7) noted the rather unusual phenomenon of boron segregating much more strongly to grain boundaries of Ni 3 Al than to free surfaces, while sulfur (an embrittling impurity) was shown to exhibit the opposite effect

  13. Boron deprivation alters rat behaviour and brain mineral composition differently when fish oil instead of safflower oil is the diet fat source.

    Science.gov (United States)

    Nielsen, Forrest H; Penland, James G

    2006-01-01

    To determine whether boron deprivation affects rat behaviour and whether behavioural responses to boron deprivation are modified by differing amounts of dietary long-chain omega-3 fatty acids. Female rats were fed diets containing 0.1 mg (9 micromol)/kg boron in a factorial arrangement with dietary variables of supplemental boron at 0 and 3mg (278 micromol)/kg and fat sources of 75 g/kg safflower oil or 65 g/kg fish (menhaden) oil plus 10 g/kg linoleic acid. After 6 weeks, six females per treatment were bred. Dams and pups continued on their respective diets through gestation, lactation and after weaning. Between ages 6 and 20 weeks, behavioural tests were performed on 13-15 male offspring from three dams in each dietary treatment. The rats were euthanized at age 21 weeks for the collection of tissues and blood. At ages 6 and 19 weeks, auditory startle was evaluated with an acoustic startle system and avoidance behaviour was evaluated by using an elevated plus maze. At ages 7 and 20 weeks, spontaneous behaviour activity was evaluated with a photobeam activity system. A brightness discrimination test was performed on the rats between age 15 and 16 weeks. Brain mineral composition was determined by coupled argon plasma atomic emission spectroscopy. Plasma total glutathione was determined by HPLC and total cholesterol and 8-iso-prostaglandin F2alpha (8-iso-PGF2alpha) were determined by using commercially available kits. Boron-deficient rats were less active than boron-adequate rats when fed safflower oil based on reduced number, distance and time of horizontal movements, front entries, margin distance and vertical breaks and jumps in the spontaneous activity evaluation. Feeding fish oil instead of safflower oil attenuated the activity response to boron deprivation. In the plus maze evaluation, the behavioural reactivity of the boron-deficient rats fed fish oil was noticeably different than the other three treatments. They made more entries into both open and closed

  14. A parameter study to determine the optimal source neutron energy in boron neutron capture therapy of brain tumours

    Energy Technology Data Exchange (ETDEWEB)

    Nievaart, V A [Reactor Physics Department, Delft University of Technology, Mekelweg 15, 2629JB Delft (Netherlands); Moss, R L [Joint Research Centre of the European Commission, Postbus 2, 1755ZG Petten (Netherlands); Kloosterman, J L [Reactor Physics Department, Delft University of Technology, Mekelweg 15, 2629JB Delft (Netherlands); Hagen, T H J J van der [Reactor Physics Department, Delft University of Technology, Mekelweg 15, 2629JB Delft (Netherlands); Dam, H van [Reactor Physics Department, Delft University of Technology, Mekelweg 15, 2629JB Delft (Netherlands)

    2004-09-21

    The values of the parameters used in boron neutron capture therapy (BNCT) to calculate a given dose to human tissue vary with patients due to different physical, biological and/or medical circumstances. Parameters include the tissue dimensions, the {sup 10}B concentration and the relative biological effectiveness (RBE) factors for the different dose components associated with BNCT. Because there is still no worldwide agreement on RBE values, more often than not, average values for these parameters are used. It turns out that the RBE-problem can be circumvented by taking into account all imaginable parameter values. Approaching this quest from another angle: the outcome will also provide the parameters (and values) which influence the optimal source neutron energy. For brain tumours it turns out that the {sup 10}B concentration, the RBE factors for {sup 10}B as well as fast neutrons, together with the dose limit set for healthy tissue, affect the optimal BNCT source neutron energy. By using source neutrons of a few keV together with neutrons of a few eV, it ensures that, under all imaginable circumstances, a maximum of alpha (and lithium) particles can be delivered in the tumour.

  15. Development of high intensity ion sources for a Tandem-Electrostatic-Quadrupole facility for Accelerator-Based Boron Neutron Capture Therapy

    International Nuclear Information System (INIS)

    Bergueiro, J.; Igarzabal, M.; Suarez Sandin, J.C.; Somacal, H.R.; Thatar Vento, V.; Huck, H.; Valda, A.A.; Repetto, M.

    2011-01-01

    Several ion sources have been developed and an ion source test stand has been mounted for the first stage of a Tandem-Electrostatic-Quadrupole facility For Accelerator-Based Boron Neutron Capture Therapy. A first source, designed, fabricated and tested is a dual chamber, filament driven and magnetically compressed volume plasma proton ion source. A 4 mA beam has been accelerated and transported into the suppressed Faraday cup. Extensive simulations of the sources have been performed using both 2D and 3D self-consistent codes.

  16. Development of high intensity ion sources for a Tandem-Electrostatic-Quadrupole facility for Accelerator-Based Boron Neutron Capture Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Bergueiro, J. [Gerencia de Investigacion y Aplicaciones, Comision Nacional de Energia Atomica (Argentina)] [CONICET, Buenos Aires (Argentina); Igarzabal, M.; Suarez Sandin, J.C. [Gerencia de Investigacion y Aplicaciones, Comision Nacional de Energia Atomica (Argentina); Somacal, H.R. [Gerencia de Investigacion y Aplicaciones, Comision Nacional de Energia Atomica (Argentina)] [Escuela de Ciencia y Tecnologia, Universidad Nacional de San Martin (Argentina); Thatar Vento, V. [Gerencia de Investigacion y Aplicaciones, Comision Nacional de Energia Atomica (Argentina)] [CONICET, Buenos Aires (Argentina); Huck, H.; Valda, A.A. [Gerencia de Investigacion y Aplicaciones, Comision Nacional de Energia Atomica (Argentina)] [Escuela de Ciencia y Tecnologia, Universidad Nacional de San Martin (Argentina); Repetto, M. [Gerencia de Investigacion y Aplicaciones, Comision Nacional de Energia Atomica (Argentina)

    2011-12-15

    Several ion sources have been developed and an ion source test stand has been mounted for the first stage of a Tandem-Electrostatic-Quadrupole facility For Accelerator-Based Boron Neutron Capture Therapy. A first source, designed, fabricated and tested is a dual chamber, filament driven and magnetically compressed volume plasma proton ion source. A 4 mA beam has been accelerated and transported into the suppressed Faraday cup. Extensive simulations of the sources have been performed using both 2D and 3D self-consistent codes.

  17. Development of high intensity ion sources for a Tandem-Electrostatic-Quadrupole facility for Accelerator-Based Boron Neutron Capture Therapy.

    Science.gov (United States)

    Bergueiro, J; Igarzabal, M; Sandin, J C Suarez; Somacal, H R; Vento, V Thatar; Huck, H; Valda, A A; Repetto, M; Kreiner, A J

    2011-12-01

    Several ion sources have been developed and an ion source test stand has been mounted for the first stage of a Tandem-Electrostatic-Quadrupole facility For Accelerator-Based Boron Neutron Capture Therapy. A first source, designed, fabricated and tested is a dual chamber, filament driven and magnetically compressed volume plasma proton ion source. A 4 mA beam has been accelerated and transported into the suppressed Faraday cup. Extensive simulations of the sources have been performed using both 2D and 3D self-consistent codes. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. Bayesian Nitrate Source Apportionment to Individual Groundwater Wells in the Central Valley by use of Nitrogen, Oxygen, and Boron Isotopic Tracers

    Science.gov (United States)

    Lockhart, K.; Harter, T.; Grote, M.; Young, M. B.; Eppich, G.; Deinhart, A.; Wimpenny, J.; Yin, Q. Z.

    2014-12-01

    Groundwater quality is a concern in alluvial aquifers underlying agricultural areas worldwide, an example of which is the San Joaquin Valley, California. Nitrate from land applied fertilizers or from animal waste can leach to groundwater and contaminate drinking water resources. Dairy manure and synthetic fertilizers are the major sources of nitrate in groundwater in the San Joaquin Valley, however, septic waste can be a major source in some areas. As in other such regions around the world, the rural population in the San Joaquin Valley relies almost exclusively on shallow domestic wells (≤150 m deep), of which many have been affected by nitrate. Consumption of water containing nitrate above the drinking water limit has been linked to major health effects including low blood oxygen in infants and certain cancers. Knowledge of the proportion of each of the three main nitrate sources (manure, synthetic fertilizer, and septic waste) contributing to individual well nitrate can aid future regulatory decisions. Nitrogen, oxygen, and boron isotopes can be used as tracers to differentiate between the three main nitrate sources. Mixing models quantify the proportional contributions of sources to a mixture by using the concentration of conservative tracers within each source as a source signature. Deterministic mixing models are common, but do not allow for variability in the tracer source concentration or overlap of tracer concentrations between sources. Bayesian statistics used in conjunction with mixing models can incorporate variability in the source signature. We developed a Bayesian mixing model on a pilot network of 32 private domestic wells in the San Joaquin Valley for which nitrate as well as nitrogen, oxygen, and boron isotopes were measured. Probability distributions for nitrogen, oxygen, and boron isotope source signatures for manure, fertilizer, and septic waste were compiled from the literature and from a previous groundwater monitoring project on several

  19. Stability of high-speed lithium sheet jets for the neutron source in Boron Neutron Capture Therapy (BNCT)

    International Nuclear Information System (INIS)

    Nakagawa, Masamichi; Takahashi, Minoru; Aritomi, Masanori; Kobayashi, Toru

    2014-01-01

    The stability of high-speed liquid lithium sheet jets was analytically studied for the neutron source in Boron Neutron Capture Therapy (BNCT), which makes cancers and tumors curable with cell-level selections and hence high QOL. The object of our research is to realize the thin and high-speed plane sheet jets of liquid lithium in a high-vacuum as an accelerator target. Linear analysis approach is made to the stability on thin plane sheet jets of liquid lithium in a high-vacuum, and then our analytical results were compared with the previous experimental ones. We proved that the waves of surface tension on thin lithium sheet jets in a high-vacuum are of supercritical flows and neutral stable under about 17.4 m/s in flow velocity and that the fast non-dispersive anti-symmetric waves are more significant than the very slow dispersive symmetric waves. We also formulated the equation of shrinking angle in isosceles-triangularly or isosceles-trapezoidal shrinking sheet jets corresponding to the Mach angle of supersonic gas flows. This formula states universally the physical meaning of Weber number of sheet jets on the wave of surface tension in supercritical flows. We obtained satisfactory prospects (making choice of larger flow velocity U and larger thickness of sheet a) to materialize a liquid target of accelerator in BNCT. (author)

  20. Calculations of neutron source at the KYIV research reactor for the boron neutron capture therapy aims

    International Nuclear Information System (INIS)

    Gritzay, O.; Kalchenko, O.; Klimova, N.; Razbudey, V.; Sanzhur, A.

    2006-01-01

    Calculation results of an epithermal neutron source which can be created at the Kyiv Research Reactor (KRR) by means of placing of specially selected moderators, filters, collimators, and shielding into the 10-th horizontal experimental tube (so-called thermal column) are presented. The general Monte-Carlo radiation transport code MCNP4C [1], the Oak Ridge isotope generation code ORIGEN2 [2] and the NJOY99 [3] nuclear data processing system have been used for these calculations

  1. Boron reclamation

    International Nuclear Information System (INIS)

    Smith, R.M.

    1980-07-01

    A process to recover high purity 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

  2. Fontes e doses de boro em porta-enxertos de seringueira Sources and rates of boron in rubber rootstocks

    Directory of Open Access Journals (Sweden)

    Adônis Moreira

    2006-08-01

    Full Text Available Este trabalho teve por objetivo avaliar o efeito da aplicação de boro sobre o incremento do diâmetro do caule no ponto de enxertia, 5 cm acima do coleto, número e diâmetro de raízes laterais e estado nutricional de porta-enxertos para produção de toco enxertado de raiz nua. O delineamento experimental foi o de blocos ao acaso, em esquema fatorial 2x5: duas fontes (ulexita, 10% de B e ácido bórico, 17% de B e cinco doses de B (0, 2, 4, 8 e 16 kg ha-1 com quatro repetições. Em condições edafoclimáticas locais, curvas de resposta indicam aumentos significativos, no incremento do diâmetro do caule, no ponto de enxertia, nas doses 6,5 e 16 kg ha-1 de B, e no número de raízes laterais, nas doses 13,9 e 16 kg ha-1 de B, com aplicação de ácido bórico e de ulexita, respectivamente. As doses de B não afetaram o número de raízes. O nível crítico de B na folha de mudas de seringueira, alcançado com aplicação de ácido bórico, é de 31,8 mg kg-1. As doses de B apresentam interações significativas com os teores foliares de B, Mn e Zn, enquanto os teores foliares de N, P, K, Ca, Mg, S, Na, Cu e Fe não variaram significativamente em razão das doses de B.The objective of this work was to evaluate the effect of boron supply on the increment of stem diameter, number and diameter of lateral roots and the nutritional status of rubber rootstocks at the budding height (5 cm above the root collar, for the production of base root budded stumps, in a Xanthic Ferralsol. The experimental design was in randomized blocks, in a 2x5 factorial scheme: two sources (ulexite - 10% of B and boric acid - 17% of B and five B rates (0, 2, 4, 8 and 16 kg ha-1, with four replicates. Under the local conditions, the response curves showed significant increases in increment of stem diameter at 6.5 and 16 kg ha-1 B, and in the number of lateral roots at 13.9 and 16 kg ha-1 B, with boric acid and ulexite, respectively. The B rate did not improve the number

  3. The visual in sport history: approaches, methodologies and sources

    OpenAIRE

    Huggins, Mike

    2015-01-01

    Historians of sport now increasingly accept that visual inquiry offers another dimension to social and cultural research into sport and its history. It is complex and its boundaries are rapidly evolving. This overview offers a justification for placing more emphasis on visual approaches and an introduction to the study and interpretation of visual culture in relation to the history of sport. It stresses the importance of adopting a critical approach and the need to be reflective about that cr...

  4. Boron supplementation in broiler diets

    Directory of Open Access Journals (Sweden)

    EJ Fassani

    2004-12-01

    Full Text Available Boron supplementation in broiler feed is not a routine practice. However, some reports suggest a positive effect of boron on performance. This study assessed the effects of boron supplementation on broiler performance. Diets were based on maize and soybean meal, using boric acid P.A. as boron source. Six supplementation levels (0, 30, 60, 90, 120 and 150 ppm were evaluated using 1,440 one-day old males housed at a density of 30 chickens in each of 48 experimental plots of 3m². A completely randomized block design was used with 8 replicates. Feed intake, weight gain and feed conversion were assessed in the periods from 1 to 7 days, 1 to 21 days and 1 to 42 days of age, and viability was evaluated for the total 42-day rearing period. No performance variable was affected by boron supplementation (p>0.05 in the period from 1 to 7 days. The regression analysis indicated an ideal level of 37.4 ppm of boron for weight gain from 1 to 21 days (p0.05, although feed intake was reduced linearly with increased boron levels (p0.05. Ash and calcium percentages in the tibias of broilers and viability in the total rearing period were not affected by boron supplementation (p>0.05.

  5. Single-source-precursor Synthesis and High-temperature Behavior of SiC Ceramics Containing Boron

    Science.gov (United States)

    Gui, Miaomiao; Fang, Yunhui; Yu, Zhaoju

    2014-12-01

    In this paper, a hyperbranched polyborocarbosilane (HPBCS) was prepared by a one-pot synthesis with Cl2Si(CH3)CH2Cl, Cl3SiCH2Cl and BCl3 as the starting materials. The obtained HPBCS was characterized by GPC, FT-IR and NMR, and was confirmed to have hyperbranched structures. The thermal property of the resulting HPBCS was investigated by TGA. The ceramic yield of the HPBCS is about 84% and that of the counterpart hyperbranched hydridopolycarbosilane is only 45%, indicating that the introduction of boron into the preceramic polymer significantly improved the ceramic yield. With the polymer-derived ceramic route, the final ceramics were annealed at 1800 °C in argon atmosphere for 2 h in order to characterize the microstructure and to evaluate the high-temperature behavior. The final ceramic microstructure was studied by XRD and SEM, indicating that the introduction of boron dramatically inhibits SiC crystallization. The boron-containing SiC ceramic shows excellent high-temperature behavior against decomposition and crystallization at 1800 °C.

  6. Sources of History for "A Psychology of Verbal Communication"

    Science.gov (United States)

    O'Connell, Daniel C.; Kowal, Sabine

    2011-01-01

    There is a standard version of the history of modern mainstream psycholinguistics that emphasizes an extraordinary explosion of research in mid twentieth century under the guidance and leadership of George A. Miller and Noam Chomsky. The narrative is cast as a dramatic shift away from behavioristic principles and toward mentalistic principles…

  7. The Study on Weldability of Boron Steel and Hot-Stamped Steel by Using Laser Heat Source (Ⅲ) - Comparison on Laser Weldability of Boron Steel and Hot -Stamped Steel-

    Energy Technology Data Exchange (ETDEWEB)

    Choi, So Young; Kim, Jong Do [Korea Maritime and Ocean University, Busan (Korea, Republic of); Kim, Jong Su [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of)

    2015-01-15

    This study was conducted to compare the laser weldability of boron steel and hot-stamped steel. In general, boron steel is used in the hot-stamping process. Hot-stamping is a method for simultaneously forming and cooling boron steel in a press die after heating it to the austenitizing temperature. Hot-stamped steel has a strength of 1500 MPa or more. Thus, in this study, the laser weldability of boron steel and that of hot-stamped steel were investigated and compared. A continuous wave disk laser was used to produce butt and lap joints. In the butt welding, the critical cooling speed at which full penetration was obtained in the hot-stamped steel was lower than that of boron steel. In the lap welding, the joint widths were similar regardless of the welding speed when full penetration was obtained.

  8. The Study on Weldability of Boron Steel and Hot-Stamped Steel by Using Laser Heat Source (Ⅲ) - Comparison on Laser Weldability of Boron Steel and Hot -Stamped Steel-

    International Nuclear Information System (INIS)

    Choi, So Young; Kim, Jong Do; Kim, Jong Su

    2015-01-01

    This study was conducted to compare the laser weldability of boron steel and hot-stamped steel. In general, boron steel is used in the hot-stamping process. Hot-stamping is a method for simultaneously forming and cooling boron steel in a press die after heating it to the austenitizing temperature. Hot-stamped steel has a strength of 1500 MPa or more. Thus, in this study, the laser weldability of boron steel and that of hot-stamped steel were investigated and compared. A continuous wave disk laser was used to produce butt and lap joints. In the butt welding, the critical cooling speed at which full penetration was obtained in the hot-stamped steel was lower than that of boron steel. In the lap welding, the joint widths were similar regardless of the welding speed when full penetration was obtained

  9. The History and Evolution of Young and Distant Radio Sources

    Science.gov (United States)

    Collier, Jordan

    We study two classes of object to gain a better understanding of the evolution of Active Galactic Nuclei (AGN): Infrared-Faint Radio Sources (IFRSs) and Gigahertz Peaked Spectrum (GPS) / Compact Steep Spectrum (CSS) sources. IFRSs are a recently discovered rare class of object, which were found to be strong in the radio but undetectable in extremely sensitive infrared observations from the Spitzer Space Telescope, even in stacked images with sigma 3. Therefore, IFRSs may significantly increase the number of known high-redshift galaxies. However, their non-detections in the optical and infrared prevented confirmation of their nature. Previous studies of IFRSs focused on very sensitive observations of a few small regions of the sky, and the largest sample consisted of 55 IFRSs. However, we follow the strategy of combining radio data with IR and optical data for a large region of the sky. Using these data, we discover a population of >1300 brighter IFRSs which are, for the first time, reliably detected in the infrared and optical. We present the first spectroscopic redshifts of IFRSs and show that the brightest IFRSs are at z > 2. Furthermore, we rule out that IFRSs are Star Forming Galaxies, hotspots, lobes or misidentifications. We find the first X-ray counterparts of IFRSs, and increase the number of known polarised IFRSs five-fold. We present an analysis of their radio spectra and show that IFRSs consist of GPS, CSS and ultra-steep-spectrum sources. We follow up >50 of these using VLBI observations, and confirm the AGN status of IFRSs. GPS and CSS sources are compact radio sources with a convex radio spectrum. They are widely thought to represent young and evolving radio galaxies that have recently launched their jets. However, good evidence exists in individual cases that GPS and CSS sources are one of the following: 1) frustrated by interactions with dense gas and dust in their environment; 2) prematurely dying radio sources; 3) recurrent radio galaxies. Their

  10. Deposition of multicomponent chromium carbide coatings using a non-conventional source of chromium and silicon with micro-additions of boron

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Ruiz, Jesus Eduardo, E-mail: jesus.gonzalez@biomat.uh.cu [Biomaterials Center, University of Havana (Cuba); Rodriguez Cristo, Alejandro [Mechanical Plants Company, Road of the Sub-Plan, Farm La Cana, Santa Clara, Villa Clara (Cuba); Ramos, Adrian Paz [Department of Chemistry, Universite de Montreal, Quebec (Canada); Quintana Puchol, Rafael [Welding Research Center, Central University Marta Abreu of Las Villas, Villa Clara (Cuba)

    2017-01-15

    The chromium carbide coatings are widely used in the mechanical industry due to its corrosion resistance and mechanical properties. In this work, we evaluated a new source of chromium and silicon with micro-additions of boron on the deposition of multi-component coatings of chromium carbides in W108 steel. The coatings were obtained by the pack cementation method, using a simultaneous deposition at 1000 deg for 4 hours. The coatings were analyzed by X-ray diffraction, X-ray energy dispersive spectroscopy, optical microscopy, microhardness test method and pin-on-disc wear test. It was found that the coatings formed on W108 steel were mainly constituted by (Cr,Fe){sub 23}C{sub 6} , (Cr,Fe){sub 7} C{sub 3} , Cr{sub 5-x}Si{sub 3-x} C{sub x+z}, Cr{sub 3} B{sub 0,44}C{sub 1,4} and (or) Cr{sub 7} BC{sub 4} . The carbide layers showed thicknesses between 14 and 15 μm and maximum values of microhardness between 15.8 and 18.8 GPa. Also, the micro-additions of boron to the mixtures showed statistically significant influence on the thickness, microhardness and abrasive wear resistance of the carbide coatings. (author)

  11. Using Sources to Teach History for the Common Good: A Case of One Teacher's Purpose

    Science.gov (United States)

    Gradwell, Jill M.

    2010-01-01

    The teacher who is the focus of this interpretive case study, uses primary sources regularly with her students in ambitious ways but does so less from the current reform efforts, recent history education scholarship, or the climate of accountability and more from her individual goals for history education, most significantly, to prepare her…

  12. Sources of history for "a psychology of verbal communication".

    Science.gov (United States)

    O'Connell, Daniel C; Kowal, Sabine

    2011-02-01

    There is a standard version of the history of modern mainstream psycholinguistics that emphasizes an extraordinary explosion of research in mid twentieth century under the guidance and leadership of George A. Miller and Noam Chomsky. The narrative is cast as a dramatic shift away from behavioristic principles and toward mentalistic principles based largely on transformational linguistics. A closer view of the literature diminishes the historical importance of behaviorism, shows a prevailing "written language bias" (Linell in The written language bias in linguistics: Its nature, origins and transformations, Routledge, London, 2005, p. 4) in psycholinguistic research, and elevates some theoretical and empirical thinking of the late nineteenth and the early twentieth centuries on language and language use to a far more important role than has heretofore been acknowledged. In keeping with the theoretical and methodological perspective of the present article, it is particularly appropriate that the German philologist Philipp Wegener be "given his due in the annals of linguistic sciences" (Koerner 1991, p. VI*). In his (1885/1991) Untersuchungen über die Grundfragen des Sprachlebens (Investigations regarding the fundamental questions of the life of language; our translation), he began his philological research with the investigation of actual speaking in everyday settings rather than with analyses of purely formal structure. Moreover, he emphasized understanding language and localized this function in the listener. Compatible with Wegener's own investigations is another aspect of speaking that has been most seriously neglected throughout the history of research on the psychology of verbal communication. For him, as well as for Esper (In C. Murchison [Ed.], A handbook of social psychology, Clark University Press, Worchester, MA, 1935), the basic and primary genre of dialogical discourse was not ongoing conversation, but the occasional use of speech in association with

  13. New techniques for producing thin boron films

    International Nuclear Information System (INIS)

    Thomas, G.E.

    1988-01-01

    A review will be presented of methods for producing thin boron films using an electron gun. Previous papers have had the problem of spattering of the boron source during the evaporation. Methods for reducing this problem will also be presented. 12 refs., 4 figs

  14. Deriving consumer-facing disease concepts for family health histories using multi-source sampling.

    Science.gov (United States)

    Hulse, Nathan C; Wood, Grant M; Haug, Peter J; Williams, Marc S

    2010-10-01

    The family health history has long been recognized as an effective way of understanding individuals' susceptibility to familial disease; yet electronic tools to support the capture and use of these data have been characterized as inadequate. As part of an ongoing effort to build patient-facing tools for entering detailed family health histories, we have compiled a set of concepts specific to familial disease using multi-source sampling. These concepts were abstracted by analyzing family health history data patterns in our enterprise data warehouse, collection patterns of consumer personal health records, analyses from the local state health department, a healthcare data dictionary, and concepts derived from genetic-oriented consumer education materials. Collectively, these sources yielded a set of more than 500 unique disease concepts, represented by more than 2500 synonyms for supporting patients in entering coded family health histories. We expect that these concepts will be useful in providing meaningful data and education resources for patients and providers alike.

  15. Demonstration of a high-intensity neutron source based on a liquid-lithium target for Accelerator based Boron Neutron Capture Therapy.

    Science.gov (United States)

    Halfon, S; Arenshtam, A; Kijel, D; Paul, M; Weissman, L; Berkovits, D; Eliyahu, I; Feinberg, G; Kreisel, A; Mardor, I; Shimel, G; Shor, A; Silverman, I; Tessler, M

    2015-12-01

    A free surface liquid-lithium jet target is operating routinely at Soreq Applied Research Accelerator Facility (SARAF), bombarded with a ~1.91 MeV, ~1.2 mA continuous-wave narrow proton beam. The experiments demonstrate the liquid lithium target (LiLiT) capability to constitute an intense source of epithermal neutrons, for Accelerator based Boron Neutron Capture Therapy (BNCT). The target dissipates extremely high ion beam power densities (>3 kW/cm(2), >0.5 MW/cm(3)) for long periods of time, while maintaining stable conditions and localized residual activity. LiLiT generates ~3×10(10) n/s, which is more than one order of magnitude larger than conventional (7)Li(p,n)-based near threshold neutron sources. A shield and moderator assembly for BNCT, with LiLiT irradiated with protons at 1.91 MeV, was designed based on Monte Carlo (MCNP) simulations of BNCT-doses produced in a phantom. According to these simulations it was found that a ~15 mA near threshold proton current will apply the therapeutic doses in ~1h treatment duration. According to our present results, such high current beams can be dissipated in a liquid-lithium target, hence the target design is readily applicable for accelerator-based BNCT. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Produção e qualidade de frutos de laranjeira 'Pêra' em função de fontes e doses de boro Yield and quality of 'Pera' sweet orange in effect of boron source and doses

    Directory of Open Access Journals (Sweden)

    Isabela Rodrigues Bologna

    2006-08-01

    Full Text Available O presente trabalho objetivou estudar o efeito de fontes e doses de boro aplicadas no solo na produção e qualidade dos frutos de laranjeira 'Pêra'. Os tratamentos constituíram-se de cinco fontes de boro (ulexita-pó, colemanita, ulexita-granulada, termofosfato magnesiano com boro e ácido bórico e quatro doses (1; 2; 3 e 4 kg ha-1, em delineamento inteiramente casualizado e esquema fatorial 5 x 4, em quatro repetições. A produção da cultura não sofreu influência das fontes e doses de boro, 11 meses após a aplicação dos tratamentos. Nos atributos tecnológicos, não foram observados efeitos significativos nos parâmetros: ratio, teor de sólidos solúveis e ºBrix. Houve redução do rendimento de suco com o aumento da dose de boro aplicada para todas as fontes testadas. O maior e o menor diâmetro de fruto foram obtidos, respectivamente, com o uso da fonte mais solúvel (ácido bórico e menos solúvel (colemanita, não havendo influência dos tratamentos na espessura de casca.The aim of this research was to evaluate effects of boron sources and doses in the yield and quality of 'Pera' sweet orange. The treatments were five boron sources (ulexite-powder, colemanite, ulexite-grain, magnesian thermo phosphate with boron and acid boric and four boron doses (1, 2, 3 and 4 kg ha-1. Experimental design was completely randomized in factorial 5 x 4, with four replications. Eleven months after treatments application crop yield was not influenced by boron source and doses. Fruit technological attributes as ratio, soluble solid contents and ºBrix were not different. Orange juice production decreased with boron dose increasing for all evaluated sources. The largest fruit diameter was found under the most soluble source (boric acid while the smallest fruit diameter was obtained under the less soluble source (colemanite. Treatment influence was not observed to fruit skin thickness.

  17. Simultaneous attentional guidance by working-memory and selection history reveals two distinct sources of attention.

    Science.gov (United States)

    Schwark, Jeremy D; Dolgov, Igor; Sandry, Joshua; Volkman, C Brooks

    2013-10-01

    Recent theories of attention have proposed that selection history is a separate, dissociable source of information that influences attention. The current study sought to investigate the simultaneous involvement of selection history and working-memory on attention during visual search. Experiments 1 and 2 used target feature probability to manipulate selection history and found significant effects of both working-memory and selection history, although working-memory dominated selection history when they cued different locations. Experiment 3 eliminated the contribution of voluntary refreshing of working-memory and replicated the main effects, although selection history became dominant. Using the same methodology, but with reduced probability cue validity, both effects were present in Experiment 4 and did not significantly differ in their contribution to attention. Effects of selection history and working-memory never interacted. These results suggest that selection history and working-memory are separate influences on attention and have little impact on each other. Theoretical implications for models of attention are discussed. © 2013.

  18. History from Children's Perspectives: Learning to Read and Write Historical Accounts Using Family Sources

    Science.gov (United States)

    Schmidt, Maria Auxiliadora; Garcia, Tania Maria F. Braga

    2010-01-01

    This paper presents the results of an investigation which was part of a project called "Recreating Histories". It is concerned with the analysis of historical narratives created by the children who participated in the project and an analysis of historical sources kept by families who live in Campina Grande do Sul (Brazil). It draws on…

  19. Songs as Sources of Ijebu-Ode Fashion History | Akinwumi | Journal ...

    African Journals Online (AJOL)

    ... glimpses of the state of the art of fabrics of those times. This espousal of textile technology is a significant aspect of costume history. On the whole, the paper has demonstrated the potential of the content of indigenous songs as sources of dress-fabric, fashion trends and event-dress in their wider socio-cultural contexts.

  20. Boron ion beam production with the supernanogan ECR ion source for the CERN BIO-LEIR facility

    CERN Document Server

    Stafford-Haworth, J; Scrivens, R; Toivanen, V; Röhrich, J

    2014-01-01

    To deliver B3+ ions for medical research the compounds decaborane and m-carborane were tested using the metal ions from volatile compounds (MIVOC) method with the Supernanogan 14.5 GHz ECR ion source. Using decaborane the source delivered less than 10 A intensity of B3+ and after operation large deposits of material were found inside the source. Using m-carborane 50 A of B3+ were delivered without support gas. For m-carborane, helium and oxygen support gasses were also tested, and the effects of different source tuning parameters are discussed. The average consumption of m-carborane was 0:1 mg/Ah over all operation.

  1. For fun and profit a history of the free and open source software revolution

    CERN Document Server

    Tozzi, Christopher

    2017-01-01

    In the 1980s, there was a revolution with far-reaching consequences -- a revolution to restore software freedom. In the early 1980s, after decades of making source code available with programs, most programmers ceased sharing code freely. A band of revolutionaries, self-described "hackers," challenged this new norm by building operating systems with source code that could be freely shared. In For Fun and Profit, Christopher Tozzi offers an account of the free and open source software (FOSS) revolution, from its origins as an obscure, marginal effort by a small group of programmers to the widespread commercial use of open source software today. Tozzi explains FOSS's historical trajectory, shaped by eccentric personalities -- including Richard Stallman and Linus Torvalds -- and driven both by ideology and pragmatism, by fun and profit. Tozzi examines hacker culture and its influence on the Unix operating system, the reaction to Unix's commercialization, and the history of early Linux development. He describes ...

  2. Compact D-D Neutron Source-Driven Subcritical Multiplier and Beam-Shaping Assembly for Boron Neutron Capture Therapy

    International Nuclear Information System (INIS)

    Ganda, Francesco; Vujic, Jasmina; Greenspan, Ehud; Leung, Ka-Ngo

    2010-01-01

    This work assesses the feasibility of using a small, safe, and inexpensive keff 0.98 subcritical fission assembly [subcritical neutron multiplier (SCM)] to amplify the treatment neutron beam intensity attainable from a compact deuterium-deuterium (D-D) fusion neutron source delivering [approximately]1012 n/s. The objective is to reduce the treatment time for deep-seated brain tumors to [approximately]1 h. The paper describes the optimal SCM design and two optimal beam-shaping assemblies (BSAs) - one designed to maximize the dose rate and the other designed to maximize the total dose that can be delivered to a deep-seated tumor. The neutron beam intensity amplification achieved with the optimized SCM and BSA results in an increase in the treatment dose rate by a factor of 18: from 0.56 Gy/h without the SCM to 10.1 Gy/h. The entire SCM is encased in an aluminum structure. The total amount of 20% enriched uranium required for the SCM is 8.5 kg, and the cost (not including fabrication) is estimated to be less than $60,000. The SCM power level is estimated at 400 W when driven by a 1012 n/s D-D neutron source. This translates into consumption of only [approximately]0.6% of the initially loaded 235U atoms during 50 years of continuous operation and implies that the SCM could operate continuously for the entire lifetime of the facility without refueling. Cooling the SCM does not pose a challenge; it may be accomplished by natural circulation as the maximum heat flux is only 0.034 W/cm2.

  3. Aspects of the chemistry of boron

    International Nuclear Information System (INIS)

    Moellinger, H.

    1976-01-01

    Crystal phases of elementary boron are reviewed as well as boron-sulphur, boron-selenum, boron-tellurium, and boron-nitrogen compounds, carboranes, and boron-carbohydrate complexes. A boron cadastre of rivers and lakes serves to illustrate the role of boron in environmental protection. Technically relevant boron compounds and their uses are mentioned. (orig.) 891 HK/orig. 892 MB [de

  4. CLASSIFICATION OF SOURCES ON HISTORY OF ARMED CONFLICT IN CHECHEN REPUBLIC IN LATE 20 TH CENTURY

    Directory of Open Access Journals (Sweden)

    Николай Николаевич Малишевский

    2014-12-01

    Full Text Available The article deals with the problems of historiography of the armed conflict in the Chechen Republic. The analysis enabled to classify available sources on this subject by the functional-specific criterion -a source and a data carrier, that is the way of its fixing, comprising three principal types of sources: written (text, cartographical and audiovisual. The information potential of available sources on the armed conflict history in Chechen Republic is not limited to certain subjects and promotes disclosing of such aspects of the conflict as: - stages (the first campaign, the second campaign, the counterterrorism operation; - opposition methods (active and passive; - opposition forms (collective and individual; - system of military-political management of territory; - scale and intensity of clashes; - a complex of actions of the state peace-making policy and feature of its realization; - specificity of participation of separate groups of the population; - regional aspect of events (on the scale of separate settlement, area etc. - conflict history in persons; - problems of the thematic literature.

  5. Si(001):B gas-source molecular-beam epitaxy: Boron surface segregation and its effect on film growth kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Kim, H.; Glass, G.; Spila, T.; Taylor, N.; Park, S.Y.; Abelson, J.R.; Greene, J.E. [Department of Materials Science, Coordinated Science Laboratory, and Materials Research Laboratory, University of Illinois, 1101 West Springfield, Urbana, Illinois 61801 (United States)

    1997-09-01

    B-doped Si(001) films, with concentrations C{sub B} up to 1.7{times}10{sup 22}cm{sup {minus}3}, were grown by gas-source molecular-beam epitaxy from Si{sub 2}H{sub 6} and B{sub 2}H{sub 6} at T{sub s}=500{endash}800{degree}C. D{sub 2} temperature-programed desorption (TPD) spectra were then used to determine B coverages {theta}{sub B} as a function of C{sub B} and T{sub s}. In these measurements, as-deposited films were flash heated to desorb surface hydrogen, cooled, and exposed to atomic deuterium until saturation coverage. Strong B surface segregation was observed with surface-to-bulk B concentration ratios ranging up to 1200. TPD spectra exhibited {beta}{sub 2} and {beta}{sub 1} peaks associated with dideuteride and monodeuteride desorption as well as lower-temperature B-induced peaks {beta}{sub 2}{sup {asterisk}} and {beta}{sub 1}{sup {asterisk}}. Increasing {theta}{sub B} increased the area under {beta}{sub 2}{sup {asterisk}} and {beta}{sub 1}{sup {asterisk}} at the expense of {beta}{sub 2} and {beta}{sub 1} and decreased the total D coverage {theta}{sub D}. The TPD results were used to determine the B segregation enthalpy, {minus}0.53eV, and to explain and model the effects of high B coverages on Si(001) growth kinetics. Film deposition rates R increase by {ge}50{percent} with increasing C{sub B}{tilde {gt}}1{times}10{sup 19}cm{sup {minus}3} at T{sub s}{le}550{degree}C, due primarily to increased H desorption rates from B-backbonded Si adatoms, and decrease by corresponding amounts at T{sub s}{ge}600{degree}C due to decreased adsorption site densities. At T{sub s}{ge}700{degree}C, high B coverages also induce {l_brace}113{r_brace} facetting. {copyright} {ital 1997 American Institute of Physics.}

  6. Competition as a source of constraint on life history evolution in natural populations.

    Science.gov (United States)

    Wilson, A J

    2014-01-01

    Competition among individuals is central to our understanding of ecology and population dynamics. However, it could also have major implications for the evolution of resource-dependent life history traits (for example, growth, fecundity) that are important determinants of fitness in natural populations. This is because when competition occurs, the phenotype of each individual will be causally influenced by the phenotypes, and so the genotypes, of competitors. Theory tells us that indirect genetic effects arising from competitive interactions will give rise to the phenomenon of 'evolutionary environmental deterioration', and act as a source of evolutionary constraint on resource-dependent traits under natural selection. However, just how important this constraint is remains an unanswered question. This article seeks to stimulate empirical research in this area, first highlighting some patterns emerging from life history studies that are consistent with a competition-based model of evolutionary constraint, before describing several quantitative modelling strategies that could be usefully applied. A recurrent theme is that rigorous quantification of a competition's impact on life history evolution will require an understanding of the causal pathways and behavioural processes by which genetic (co)variance structures arise. Knowledge of the G-matrix among life history traits is not, in and of itself, sufficient to identify the constraints caused by competition.

  7. Source criticism and cultural models: constructing life histories of women missionaries

    Directory of Open Access Journals (Sweden)

    Eila Helander

    1999-01-01

    Full Text Available Research work is an interpretive enterprise. The variety of sources poses some central methodological questions for constructing religious life histories. There is an apparent discrepancy between the source categories concerning the content of the information. Private diaries and letters provide information on women's work and life which is not available in official reports and letters. They reveal dates, events and individuals which are not mentioned elsewhere. In histography the question of discrepancy is normally solved by comparing the sources with an aim to arrive at the "true picture" of how things have been. Such a picture is believed to portray not only the true life situation of the individual or group in question but, depending on the nature of the data, also the epoch and time situation itself. From the viewpoint of social sciences and comparative religion one will ask: could the variety of sources be approached and utilized in some other way? The second question posed by the data concerns the content of each source category. The information can be located on the continuum "highly subjective — stereotyped". Subjective information, including reflections on personal experiences may not be the best source e.g. for constructing the flow of historical events, but it is of uttermost importance if we want to show how individuals respond to social constraints and actively assemble social worlds.

  8. Development and application of a labmade apparatus using open-source “arduino” hardware for the electrochemical pretreatment of boron-doped diamond electrodes

    International Nuclear Information System (INIS)

    Rosa, Thalles Ramon; Betim, Fernando Silva; Ferreira, Rafael de Queiroz

    2017-01-01

    Highlights: • BDD electrodes use an electrochemical pretreatment (anodic and/or cathodic) to restore their original characteristics and promote the reproduction of previous voltammograms; • Automatic system can carefully reproduce the electrochemical pretreatment of BDD electrode quickly and efficiently; • Open source platform “Arduino” can be used to developed a labmade apparatus to control a BDD electrode pretreatment system for analytical purposes; • The main advantages of this labmade apparatus are: low supporting electrolyte consumption (20 mL), a total time for each pretreatment of 80 seconds and an average cost of production below US$ 200. - Abstract: Every day, new electroanalytical methodologies are developed to supplant the established spectrometric and chromatographic methods due to their versatility, low cost and ability to perform measurements without sample treatment. Electroanalytical techniques have provided an alternative to quantify substances due to the direct relationship between the analyte concentration and some electrical property of the system. However, this ratio between the concentration and peak current is valid only if the electrochemically active area of the working electrode is constant in each electrochemical test. For years, classic polarography ensured the reproducibility of the mercury electrode surface due to its liquid state at room temperature. However, this metal has a high toxicity, driving the search for new inert materials for their replacement, most notably boron-doped diamond (BDD) electrodes. This electrode material has, among other attractive advantages for electroanalysis, a potential range higher than that of the mercury working electrode under the same conditions. Solid electrodes are, in general, polished to promote the reproducibility of their electrochemical performance. For BDD, the use of an electrochemical pretreatment (anodic and/or cathodic) has been sufficient to restore their original

  9. Zagreb during World War I: Historic newspapers as source for social history research

    Directory of Open Access Journals (Sweden)

    Mirjana Jurić

    2009-07-01

    Full Text Available The aim of the paper is to reconstruct the social image of Zagreb during World War I by focusing on the influence of war circumstances on urban life, the living conditions and the position of children as the most vulnerable group of inhabitants, by using primarily newspapers as historical sources. In order to achieve as complete an image as possible, various publications were used (‘Narodne novine’, ‘Jutarnji list’, ‘Obzor’, ‘Novine’, ‘Hrvatska’, ‘Ilustrovani list’, ‘Katolički list’ and ‘Narodna zaštita’ which proved to be an inexhaustible source of information and contemporary observations on the above-mentioned issues. The paper tells about the general sense of insecurity in the city during wartime, the usual war motives (the wounded in the streets, life under war regulations, forced charity events and the consequences of the war situation (shortage of living supplies and poverty, begging and vagrancy, neglected children and war orphans. The paper has proven that historic newspapers are a first-class historical source. The essential scientific contribution of the paper is the reconstruction of part of Zagreb social history during World War I, highlighting that this part of Croatian history has still been poorly and incompletely researched.

  10. Density separation of boron particles. Final report

    International Nuclear Information System (INIS)

    Smith, R.M.

    1980-04-01

    A density distribution much broader than expected was observed in lots of natural boron powder supplied by two different sources. The material in both lots was found to have a rhombohedral crystal structure, and the only other parameters which seemed to account for such a distribution were impurities within the crystal structure and varying isotopic ratios. A separation technique was established to isolate boron particles in narrow densty ranges. The isolated fractions were subsequently analyzed for B 10 and total boron content in an effort to determine whether selective isotopic enrichment and nonhomogeneous impurity distribution were the causes for the broad density distribution of the boron powders. It was found that although the B 10 content remained nearly constant around 18%, the total boron content varied from 37.5 to 98.7%. One of the lots also was found to contain an apparently high level of alpha rhombohedral boron which broadened the density distribution considerably. During this work, a capability for removing boron particles containing gross amounts of impurities and, thereby, improving the overall purity of the remaining material was developed. In addition, the separation technique used in this study apparently isolated particles with alpha and beta rhombohedral crystal structures, although the only supporting evidence is density data

  11. ISOBORDAT: An Online Data Base on Boron Isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Pennisi, M.; Adorni-Braccesi, A.; Andreani, D.; Gori, L.; Gonfiantini, R. [Istituto di Geoscienze e Georisorse, CNR, Pisa (Italy); Sciuto, P. F. [Servizio Geologico, Sismico e dei Suoli, D.G. Ambiente e Difesa del Suolo e della Costa, Regione Emilia Romagna, Bologna (Italy)

    2013-07-15

    From 1986, boron isotope data in natural substances increased sharply in scientific publications. Analytical difficulties derived from complex geochemical matrices have been faced and interlaboratory calibrations reported in the boron literature. Boron isotopes are nowdays applied to investigate boron origin and migration in natural waters, sources of boron contamination, water-rock interactions and also contribute to water resource management. This is especially important in those areas where boron content exceeds the local regulations for drinking water supply and boron sources need to be identified. ISOBORDAT, an interactive database on boron isotope composition and content in natural waters is presented to the wider community of boron isotope users. The database's structure, scope and applications are reported, along with a discussion on {delta}{sup 11}B values obtained in Italian waters. In the database boron data are structured in the following categories: rainwater, rivers, lakes, groundwater and potential contaminants. New categories (medium and high enthalpy fluids from volcanic and geothermal areas) are anticipated. ISOBORDAT aims to be as interactive as possible and will be developed taking into account information and suggestions received. The database is continually undergoing revision to keep pace with continuous data publication. Indications of data that are missing at present are greatly appreciated. (author)

  12. Structure and reactivity of boron-ate complexes derived from primary and secondary boronic esters.

    Science.gov (United States)

    Feeney, Kathryn; Berionni, Guillaume; Mayr, Herbert; Aggarwal, Varinder K

    2015-06-05

    Boron-ate complexes derived from primary and secondary boronic esters and aryllithiums have been isolated, and the kinetics of their reactions with carbenium ions studied. The second-order rate constants have been used to derive nucleophilicity parameters for the boron-ate complexes, revealing that nucleophilicity increased with (i) electron-donating aromatics on boron, (ii) neopentyl glycol over pinacol boronic esters, and (iii) 12-crown-4 ether.

  13. Boron isotopes in geothermal systems

    International Nuclear Information System (INIS)

    Aggarwal, J.

    1997-01-01

    Boron is a highly mobile element and during water-rock reactions, boron is leached out of rocks with no apparent fractionation. In geothermal systems where the water recharging the systems are meteoric in origin, the B isotope ratio of the geothermal fluid reflects the B isotope ratio of the rocks. Seawater has a distinctive B isotope ratio and where seawater recharges the geothermal system, the B isotope ratio of the geothermal system reflects the mixing of rock derived B and seawater derived B. Any deviations of the actual B isotope ratio of a mixture reflects subtle differences in the water-rock ratios in the cold downwelling limb of the hydrothermal system. This paper will present data from a variety of different geothermal systems, including New Zealand; Iceland; Yellowston, USA; Ibusuki, Japan to show the range in B isotope ratios in active geothermal systems. Some of these systems show well defined mixing trends between seawater and the host rocks, whilst others show the boron isotope ratios of the host rock only. In geothermal systems containing high amounts of CO 2 boron isotope ratios from a volatile B source can also be inferred. (auth)

  14. The 1941 villages census – an important source for studying local history

    Directory of Open Access Journals (Sweden)

    Sergiu Tabuncic

    2014-12-01

    Full Text Available The 1941 census is an important source for studying the history of the settlements from the present-time districts of Soldanesti and Rezina in the Republic of Moldova. In 1941, those localities were part of Bessarabia’s Orhei County. The materials of that census are stored at the National Archives of the Republic of Moldova, the fund No 2069, inventory 1, part 1, file 450-a. Villages Census 1941 – this is the title of the questionnaire used to collect data. The census was conducted under the auspices of the Central Institute of Statistics subordinate to the Council of Ministers of Romania. The census questionnaire contained 28 sections, each containing questions aimed to clarify the status of settlements in terms of administrative, social, economic, ethnographic, cultural, medical and religious aspects. Many questions pertained to the duration and continuity of the population’s residing in villages listed in the census and villages’ foundation years, to description of rural settlements, permanent and temporary dwellings. Also, the census results show some elements of relations between Romanians and Roma people. The 1941 census is the most significant and representative component of local history, substantially enriching the sources of this domain of research.

  15. Synthesis and characterization of ammonium phosphate fertilizers with boron

    Directory of Open Access Journals (Sweden)

    ANGELA MAGDA

    2010-07-01

    Full Text Available The concentration of boron, an essential micronutrient for plants, presents a narrow range between deficiency and toxicity. In order to provide the boron requirement for plants, and to avoid toxicity problems, boron compounds are mixed with basic fertilizers. Sodium borate pentahydrate was used as a boron source. Ammonium orthophosphates fertilizers with boron were prepared by neutralizing phosphoric acid with ammonia and addition of variable amounts of sodium tetraborate pentahydrate to the reaction mixture at a NH3:H3PO4 molar ratio of 1.5. The fertilizers obtained with boron contents ranging from 0.05 to 1 % (w/w were fully characterized by chemical analysis, thermal analysis, X-ray diffraction and infrared spectrophotometry. The studies showed that up to 500 °C, regardless of the boron content, no significant changes concerning thermal stability and nutritional properties occurred. Above 500 °C, an increase of thermal stability with an increase of the boron content was observed. X-Ray diffraction of a heat-treated sample containing 5 % (w/w boron indicated the appearance of boron orthophosphate, BPO4, as a new crystalline phase, and the disappearance of the previous structures above 500 °C, which explains the increase in thermal stability.

  16. Boron enrichment in martian clay.

    Directory of Open Access Journals (Sweden)

    James D Stephenson

    Full Text Available 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.

  17. The history and the art of anatomy: a source of inspiration even nowadays.

    Science.gov (United States)

    Mavrodi, Alexandra; Paraskevas, George; Kitsoulis, Panagiotis

    2013-01-01

    Ever since man started to study systematically medicine for the first time he recognized the value of the knowledge of Anatomy in order to safely cut and treat the human body. However, over the centuries it has been proved that Anatomy is more than just a scientific field of medicine. The fact that Anatomy requires the use of human cadavers as an object to study brought to the surface many moral issues, which adumbrated its turbulent past. Additionally, Anatomy and its inextricable element, illustration, has many times been a source of inspiration for both the anatomists and the artists. This paper aims on the one hand to provide a condensed overview of the history of Anatomy and on the other hand to investigate the way Anatomy penetrates Art and, conversely, Art penetrates Anatomy.

  18. Characterize kinematic rupture history of large earthquakes with Multiple Haskell sources

    Science.gov (United States)

    Jia, Z.; Zhan, Z.

    2017-12-01

    Earthquakes are often regarded as continuous rupture along a single fault, but the occurrence of complex large events involving multiple faults and dynamic triggering challenges this view. Such rupture complexities cause difficulties in existing finite fault inversion algorithms, because they rely on specific parameterizations and regularizations to obtain physically meaningful solutions. Furthermore, it is difficult to assess reliability and uncertainty of obtained rupture models. Here we develop a Multi-Haskell Source (MHS) method to estimate rupture process of large earthquakes as a series of sub-events of varying location, timing and directivity. Each sub-event is characterized by a Haskell rupture model with uniform dislocation and constant unilateral rupture velocity. This flexible yet simple source parameterization allows us to constrain first-order rupture complexity of large earthquakes robustly. Additionally, relatively few parameters in the inverse problem yields improved uncertainty analysis based on Markov chain Monte Carlo sampling in a Bayesian framework. Synthetic tests and application of MHS method on real earthquakes show that our method can capture major features of large earthquake rupture process, and provide information for more detailed rupture history analysis.

  19. On the Mechanism of Boron Ignition

    Science.gov (United States)

    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.

  20. Operational history of stainless steel, TiC, TiB2, and boron limiters in the ISX-B tokamak

    International Nuclear Information System (INIS)

    Emerson, L.C.; Bush, C.E.; Isler, R.C.; Langley, R.A.; Clausing, R.E.; Saltmarsh, M.J.; Whitely, J.B.; Mullendore, A.W.

    1982-01-01

    For the past eighteen months a variety of low-Z coatings have been tested for service a limiters in both ohmically-heated and beam-heated ISX-B plasmas. To date TiC, TiB 2 , and B coatings on a graphite substrate have been examined with TiC providing the best results of the three. The history of these materials in ISX-B is reviewed and compared with previously used stainless steel limiters with particular emphasis on machine performance. (orig.)

  1. An overview the boron dilution issue in PWRs

    International Nuclear Information System (INIS)

    Hyvaerinen, J.

    1994-01-01

    The presentation is an overview of boron (boric acid) dilution in pressurized water reactors (PWRs). Boric acid has been widely used in PWRs as a dissolved poison, as one of the main reactivity controlling means, for a long time, from nearly but not quite from the beginning of the design, construction and operation of PWRs in the present-day sense. The specific safety issue, namely the risk of uncontrolled reactivity insertion due to inadvertent boron dilution, is discussed first, followed by a brief look on the history of boron usage in PWRs. A discussion of boron dilution phenomenology is presented next in general terms. Some particular concerns that boron dilution phenomena arouse in the minds of a regulator will also be presented before concluding with a brief look on the future of dissolved poisons. (11 refs.)

  2. Bibliographic work of Ivan Franjo Jukić and the end of cultural history. Bibliographies as a source for the history of books and cultural history

    Directory of Open Access Journals (Sweden)

    Slavko Harni

    2009-04-01

    bibliographic analysis provides background for the study of some of Jukić’s less well known standpoints, relevant for the criteria employed in the selection of the materials for the national retrospective bibliography. The need to approach the matter from cultural and historic aspects is in correspondence with Jukić’s devout support of the Illyrian movement. This movement promoted the unity of the Southern Slavs, calling them all Illyrians and regarding them as basically a single people speaking the same language. As one of its focuses, the movement also promoted bibliographic work. Tracing back this orientation leads us to its source, the German Romanticism, which relied on the common language for the building of unity of the disunited German lands, and promoted the primacy of culture over the primacy of politics. With the German people this unity was successful, whereas the political reality, in part shaped by bloody wars, was a vivid proof of the failure of the Illyrian, and later, of the Southern Slavic idea. The course of research done for this paper was greatly affected by this historical fact, especially evident in the criteria for the selection of the bibliographic material. Starting off with the Illyrians’ understanding of what ”the regional’’ denotes, Jukić not only accepted the identification of the Illyrians and the Southern Slavs as one and the same entity, but he also treated Bosnia’s Muslims as the ”glorious Illyrian people’’, not only territorially but also ethnically. Students of the cultural and political history of Bosnia did not agree with Jukić’s arguments, and the cultural and historical processes proved him wrong by developing in directions that Jukić could not have foreseen or expected. The outcome of the Turkish siege of Bosnia was, namely, in the identification of the religious with the national. So it happened that Jukić, as a Catholic, is thought of as a Croatian culturalist and bibliographer, and a member of the Croatian

  3. Seismotectonics of Western Turkey: A Synthesis of Source Parameters and Rupture Histories of Recent Earthquakes

    Science.gov (United States)

    Taymaz, T.; Tan, O.; Yolsal, S.

    2004-12-01

    The Aegean region, including western Turkey and Greece, is indeed one of the most seismically active and rapidly deforming continental domains in the Earth. The wide range of deformational processes occurring in this region means that the eastern Mediterranean provides a unique opportunity to improve our understanding of the complex kinematics of continental collision, including strike-slip faulting and crustal extension, as well as associated seismicity and volcanism. The tectonic evolution of the Eastern Mediterranean region is dominated by effects of subduction along the Hellenic (Aegean) arc and of continental collision in eastern Anatolia and the Caucasus. Northward subduction of the African plate beneath western Anatolia and the Aegean region is causing crustal extension in the overlying Aegean province. The interplay between dynamic effects of the relative motions of adjoining plates thus controls large-scale crustal deformation and the associated earthquake activity in Turkey. The Aegean region has been subject to extension since Miocene time, and this extension has left a pronounced expression in the present-day topography. It is further widely accepted that the rapid extension observed in western Turkey is mainly accommodated by large active normal faults that control the geomorphology which is dominated by a series of E-W trending normal-fault-bounded horst and graben structures; the N-S extension inferred from these structures is consistent with regional earthquake focal mechanisms. The E-W trending Menderes graben, the NE-SW trending Burdur, Acigol and Baklan, and NW-SE trending Dinar and Sultandag-Aksehir basins all bounded by large faults form a system of half-graben whose orientation is evident in both the topography and the tilting of Neogene sediments adjacent to them. We have studied source mechanisms and rupture histories of ˜20 earthquakes using body-waveform modelling, and have compared the shapes and amplitudes of teleseismic long-period P

  4. Puzzling History--The Personal File in Residential Care: A Source for Life History and Historical Research

    Science.gov (United States)

    De Wilde, Lieselot; Vanobbergen, Bruno

    2017-01-01

    Since the turn of the century large groups of former institutionalised children have exercised their right to see their "personal files", and this has drawn widespread attention to these documents and their potential in scholarly research. This article explores the meanings of personal files from the period 1945-1984 as sources for both…

  5. Biogeochemical cycle of boron in a forest ecosystem: the case study of Montiers beech-stand

    International Nuclear Information System (INIS)

    Roux, Philippe

    2016-01-01

    This thesis aims at establishing and understanding the biogeochemical cycle of boron and its isotopes within a forest ecosystem. In that context, many questions remain concerning the dynamics of boron within terrestrial ecosystems: - What are the major sources of boron? - What type of transfer occurs between the compartments of the environment? - What mechanisms are controlling those transfers? In order to establish this biogeochemical cycle, we quantified the different stocks (vegetation, humus and soil) and fluxes (atmospheric dust and dissolved deposition, throughfall, stem-flows, litterfall and drainage) of boron in the study site of Montiers. The use of boron isotopes will give us insight concerning the mechanisms controlling the dynamics of boron. This thesis is divided in 4 main parts: 1. The first part aims at establishing a new method of extraction, purification and measurement of boron and its isotopes within vegetation samples. 2. The second part focuses on the sources and mechanisms controlling boron within atmospheric dust and dissolved deposition on the study site of Montiers. 3. The third part aims at establishing the stocks and fluxes of boron on two distinct soils: a rendisoil (basic pH) and an alocrisoil (acid pH). The goal is to determine the influence of different soil properties on boron dynamics within its biogeochemical cycle. 4. The last part aims at establishing a model of boron and boron isotopes dynamics in the soil plant system. This model is mainly based of the measurement made in 2012. (author) [fr

  6. Current State and Prospects of Studying Sources on the History of Crimean Khanate in Turkish Archives »

    Directory of Open Access Journals (Sweden)

    Sh.E. Seit-Mametov

    2016-09-01

    Full Text Available Research objectives: to consider the current state of the study of sources on the history of the Crimean Khanate in Turkish archives and determine the prospects for the study of this issue. Research materials: works of domestic and foreign Orientalists in the study of the Crimean sources in Turkish archives. Results and novelty of the research: the author analyzed the current state of the study of sources on the history of the Crimean Khanate in Turkish archives. The works of such prominent scholars as A. Bennigsen, Ö. Gokbilgin, A.N. Kurat, Ch. Lemercier-Quelquejay, V.D. Smirnov and others deserve the most attention. Sophisticated paleography (age and conditions of documents of the Ottoman sources and difficulties with their translation were the main reason for their insufficient use. In their studies, Orientalists presents facsimiles of the originals of letters and their translations, give the transcript values of complex or controversial words, solve problems with the translation of dates into the modern chronology and also produce a detailed external criticism of documents: they describe their length, quality of the paper, handwriting and also decode the khans’ seals. This enables modern researchers to get acquainted with some of the earliest sources on the history of the Crimean Khanate. The author has revealed a number of new challenges that need to be addressed in the further study of sources on the history of the Crimean Khanate: translation of foreign Orientalists’ works into Russian as well as synthesis and integration of predecessors’ works, since each individual work does not cover all the documents of interest to modern scholars. The study of sources on the history of the Crimean Khanate remains a promising challenge for modern researchers, since in Turkish archives are stored unpublished documents waiting for their turn to enter into scholarly circulation.

  7. Contamination of urban garden soils with copper and boron

    Energy Technology Data Exchange (ETDEWEB)

    Purves, D

    1966-06-04

    Spectrochemical analyses of garden soils sampled in the Edinburgh and Dundee areas indicate that there is substantial contamination of urban soils with copper and boron. These soils were analyzed spectrochemically with respect to total copper and water-extractable boron content with the view of comparing the levels obtained in urban areas with levels in arable soils in rural areas. The results indicate that urban garden soils contain about four times as much copper and two to three times as much water-soluble boron as rural arable soils. The existence of such a marked disparity between the levels of two potentially toxic elements in urban and rural areas is evidence of slow poisoning of the soil environment in built-up areas and is cause for concern. While the major source of contamination of soils with copper and boron is still a matter for speculation, it is probable that the addition of soot to garden soils and the fall-out of sooty material in built-up areas where atmospheric pollution is a problem make a substantial contribution to the water-extractable boron content of urban soils. Three samples of soot from domestic chimneys, obtained from independent sources, were found on analysis to contain 640, 650 and 555 p.p.m. water-extractable boron, and it is evident that the addition to soil of even small amounts of soot with a boron content of this order would have a marked effect on its water-extractable boron content.

  8. History of Science and Conceptual Change: The Formation of Shadows by Extended Light Sources

    Science.gov (United States)

    Dedes, Christos; Ravanis, Konstantinos

    2009-09-01

    This study investigates the effectiveness of a teaching conflict procedure whose purpose was the transformation of the representations of 12-16-year-old pupils in Greece concerning light emission and shadow formation by extended light sources. The changes observed during the children’s effort to destabilize and reorganise their representations towards a model that was compatible with the respective scientific model were studied using three groups of pupils belonging to different age groups. The methodological plan implemented was based on input from the History of Science, while the parameters of the geometrical optics model were derived from Kepler’s relevant historic experiment. The effectiveness of the teaching procedure was evaluated 2 weeks after the intervention. The results showed that the majority of the subjects accepted the model of geometrical optics, i.e. the pupils were able to correctly predict and adequately justify the experimental results based on the principle of punctiform light emission. Educational and research implications are discussed.

  9. Pulverization of boron element and proportions of boron carbide in boron

    International Nuclear Information System (INIS)

    Lang, F.M.; Finck, C.

    1956-01-01

    It is possible to reduce boron element into fine powder by means of a mortar and pestle made of sintered boron carbide, the ratio of boron carbide introduced being less than one per cent. Boron element at our disposal is made of sharp edged, dark brown, little grains of average size greater than 5 μ. Grain sizes smaller than 1μ are required for applying thin layers of such boron. (author) [fr

  10. Reactive sputter deposition of boron nitride

    International Nuclear Information System (INIS)

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

    1995-10-01

    The preparation of fully dense, boron targets for use in planar magnetron sources has lead to the synthesis of Boron Nitride (BN) films by reactive rf sputtering. The deposition parameters of gas pressure, flow and composition are varied along with substrate temperature and applied bias. The films are characterized for composition using Auger electron spectroscopy, for chemical bonding using Raman spectroscopy and for crystalline structure using transmission electron microscopy. The deposition conditions are established which lead to the growth of crystalline BN phases. In particular, the growth of an adherent cubic BN coating requires 400--500 C substrate heating and an applied -300 V dc bias

  11. Proton linacs for boron neutron capture therapy

    International Nuclear Information System (INIS)

    Lennox, A.J.

    1993-08-01

    Recent advances in the ability to deliver boron-containing drugs to brain tumors have generated interest in ∼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

  12. Teaching issues of contemporary history using historical sources and modern teaching methods

    Directory of Open Access Journals (Sweden)

    Gruber Gabriela

    2017-01-01

    Full Text Available The study of history is becoming increasingly less interesting to students, despite the fact that the history teaching process has been continuously modernized during recent years. It is an observation which can be perceived even if we don`t make an elaborated research in the field. Some empirical data show us that students in secondary and High Schools are less interested in studying History than in studying Geography or other social sciences. The number of students who are determined to study History in universities has significantly dropped in recent years [1]. Of course, there are multiple causes and the factors behind this change are numerous and varied. In this paper we handle only some changes in teaching History in High Schools, as they are designed in History Curricula and in History textbooks. Therefore during the first sequence of this paper we shall analyze the History Curricula for High School, 11th and 12th grades, regarding their finalities (competencies, some relevant contents and the recommended pedagogical approaches about the teaching methods and the auxiliary material. In the second part of the paper we propose some teaching activities through which students would practice the specific competencies from their Curriculum for History. We aim at presenting attractive teaching material and learning methods and applying the methodological recommendations from the High school Curricula for History, 11th and 12th grades.

  13. 'Insane emigrants' in transit: Psychiatric patients' files as a source for the history of return migration, c. 1910

    NARCIS (Netherlands)

    Blok, G.

    2015-01-01

    This article highlights a source that can contribute to the history of migration and mental health: the case records of Eastern European emigrants who tried to enter America at the beginning of the twentieth century, but were refused entrance because of their alleged insanity. Some of these

  14. Boron-based nanostructures: Synthesis, functionalization, and characterization

    Science.gov (United States)

    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

  15. Efeito do tratamento com fontes de zinco e boro na germinação e vigor de sementes de milho Effects of maize seed treated with zinc and boron sources on germination and vigour

    Directory of Open Access Journals (Sweden)

    N.D. Ribeiro

    1994-12-01

    Full Text Available Foi conduzido um experimento no Departamento de Fitotecnia da Universidade Federal de Santa Maria, RS, no período de março a novembro de 1992, com o objetivo de verificar o efeito da aplicação de fontes de zinco e boro em sementes de milho tratadas ou não com defensivos agrícolas. Adotou-se o esquema fatorial 3x2x6, em delineamento inteiramente casualizado, com quatro repetições. Os tratamentos constaram de avaliações em três épocas (logo após o tratamento, quatro e oito meses depois, utilização de sementes de milho com e sem tratamento fítossanitário, combinados com seis fontes de zinco e boro (testemunha, Zn-Biocrop, B-Biocrop, E-Orgânico, Zn-Biocrop + B-Biocrop e Zn-Biocrop + B-Orgânico, nas doses únicas de 2,50g Zn e de 0,15g B/kg de sementes. Os resultados obtidos mostram que a aplicação da fonte Zn-Biocrop não prejudica a germinação e o vigor, pelo período de oito meses de armazenamento. O tratamento de sementes com boro (B-Biocrop e B-Orgânico diminui a germinação e o vigor.The experiment was carried during the period of march 1992 to november 1992, to study the effects of maize seed treatment with zinc, boron and pesticides, on the germination and vigour during storage. The experimental design was a complete randomized 3x2x6 fatorial with four replicátions. The treatments were three storage periods (zero, four and eight month, pesticides treatments with or without, and six sources of zinc and boron (control, Zn-Biocrop, B-Biocrop, Organic-B, Zn-Biocrop -I- B-Biocrop and Zn-Biocrop + Organic-B, in the dose 2.50g of the Zn and 0.l5g of the B/kg of seeds. The results show that Zn-Biocrop maintain high germination and vigour for eight month of storage. The boron treatment (B-Biocrop and Organic-B showed a low germination and vigour.

  16. Google earth as a source of ancillary material in a history of psychology class.

    Science.gov (United States)

    Stevison, Blake K; Biggs, Patrick T; Abramson, Charles I

    2010-06-01

    This article discusses the use of Google Earth to visit significant geographical locations associated with events in the history of psychology. The process of opening files, viewing content, adding placemarks, and saving customized virtual tours on Google Earth are explained. Suggestions for incorporating Google Earth into a history of psychology course are also described.

  17. History, Applications, and Philosophy in Mathematics Education: HAPh--A Use of Primary Sources

    Science.gov (United States)

    Jankvist, Uffe Thomas

    2013-01-01

    The article first investigates the basis for designing teaching activities dealing with aspects of history, applications, and philosophy of mathematics in unison by discussing and analyzing the different "whys" and "hows" of including these three dimensions in mathematics education. Based on the observation that a use of history, applications, and…

  18. History of Science in the Physics Curriculum: A Directed Content Analysis of Historical Sources

    Science.gov (United States)

    Seker, Hayati; Guney, Burcu G.

    2012-01-01

    Although history of science is a potential resource for instructional materials, teachers do not have a tendency to use historical materials in their lessons. Studies showed that instructional materials should be adaptable and consistent with curriculum. This study purports to examine the alignment between history of science and the curriculum in…

  19. Co-authoring History: Montpellier, the Vendée, and the Co-authorship of the Sources

    Directory of Open Access Journals (Sweden)

    István M. Szijártó

    2013-10-01

    Full Text Available The discourses of literature and history are generally regarded as two distinct genres. This essay sets out to investigate the use of fictitious, that is, the invented, as well as real elements, in addition to narrative tools in some literary and historical texts to examine whether there is evidence for a fundamental difference between them in this respect. In the first half of the article, from the juxtaposition of Merle’s historical novel, En nos vertes années, to Le Roy Ladurie’s The Beggar and the Professor, we shall see that real and fictitious elements are also interwoven in Merle’s text, just as history uses fictitious elements, necessarily and tacitly, or, in some works, in a rather provocative way. In the second half of this essay, in examining literary and historical narratives of the counter-revolution in the Vendée, it will become evident that historians also use the same narrative techniques as writers to orientate readers. While these findings would confound the normative distinction between history and literature, we cannot, however, finally conclude that there is no fundamental difference between literary fiction and history. Arguing against Alun Munslow, who claims in Authoring the Past that “’doing history’ is an authorial activity,” this present article tries to argue that, while in many aspects writing history is indistinguishable from writing fiction, the historian has co-authors: the sources themselves may enter the process of writing history. This is a conclusion that emerges from the analysis of Simon Schama’s Citizens. His text about the revolt in the Vendée points to a potential advantage of history when compared to literary fiction: historians may feel obliged to change their original point of view under the burden of the fact they themselves have enumerated—something we can call the latent but inherent co-authorship of the sources in historical narratives.

  20. Shock Response of Boron Carbide

    National Research Council Canada - National Science Library

    Dandekar, D. P. (Dattatraya Purushottam)

    2001-01-01

    .... The present work was undertaken to determine tensile/spall strength of boron carbide under plane shock wave loading and to analyze all available shock compression data on boron carbide materials...

  1. Evaluation of temperature history of a spherical nanosystem irradiated with various short-pulse laser sources

    Science.gov (United States)

    Lahiri, Arnab; Mondal, Pranab K.

    2018-04-01

    Spatiotemporal thermal response and characteristics of net entropy production rate of a gold nanosphere (radius: 50-200 nm), subjected to a short-pulse, femtosecond laser is reported. In order to correctly illustrate the temperature history of laser-metal interaction(s) at picoseconds transient with a comprehensive single temperature definition in macroscale and to further understand how the thermophysical response of the single-phase lag (SPL) and dual-phase lag (DPL) frameworks (with various lag-ratios') differs, governing energy equations derived from these benchmark non-Fourier frameworks are numerically solved and thermodynamic assessment under both the classical irreversible thermodynamics (CIT) as well as extended irreversible thermodynamics (EIT) frameworks is subsequently carried out. Under the frameworks of SPL and DPL with small lag ratio, thermophysical anomalies such as temperature overshooting characterized by adverse temperature gradient is observed to violate the local thermodynamic equilibrium (LTE) hypothesis. The EIT framework, however, justifies the compatibility of overshooting of temperature with the second law of thermodynamics under a nonequilibrium paradigm. The DPL framework with higher lag ratio was however observed to remain free from temperature overshooting and finds suitable consistency with LTE hypothesis. In order to solve the dimensional non-Fourier governing energy equation with volumetric laser-irradiation source term(s), the lattice Boltzmann method (LBM) is extended and a three-time level, fully implicit, second order accurate finite difference method (FDM) is illustrated. For all situations under observation, the LBM scheme is featured to be computationally superior to remaining FDM schemes. With detailed prediction of maximum temperature rise and the corresponding peaking time by all the numerical schemes, effects of the change of radius of the gold nanosphere, the magnitude of fluence of laser, and laser irradiation with

  2. Boronated liposome development and evaluation

    International Nuclear Information System (INIS)

    Hawthorne, M.F.

    1995-01-01

    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

  3. Stability of boron-doped graphene/copper interface: DFT, XPS and OSEE studies

    Science.gov (United States)

    Boukhvalov, D. W.; Zhidkov, I. S.; Kukharenko, A. I.; Slesarev, A. I.; Zatsepin, A. F.; Cholakh, S. O.; Kurmaev, E. Z.

    2018-05-01

    Two different types of boron-doped graphene/copper interfaces synthesized using two different flow rates of Ar through the bubbler containing the boron source were studied. X-ray photoelectron spectra (XPS) and optically stimulated electron emission (OSEE) measurements have demonstrated that boron-doped graphene coating provides a high corrosion resistivity of Cu-substrate with the light traces of the oxidation of carbon cover. The density functional theory calculations suggest that for the case of substitutional (graphitic) boron-defect only the oxidation near boron impurity is energetically favorable and creation of the vacancies that can induce the oxidation of copper substrate is energetically unfavorable. In the case of non-graphitic boron defects oxidation of the area, a nearby impurity is metastable that not only prevent oxidation but makes boron-doped graphene. Modeling of oxygen reduction reaction demonstrates high catalytic performance of these materials.

  4. Implantation of boron in silicon

    International Nuclear Information System (INIS)

    Hofker, W.K.

    1975-01-01

    The distribution versus depth of boron implanted in silicon and the corresponding electrical activity obtained after annealing are studied. The boron distributions are measured by secondary-ion mass spectrometry. Boron distributions implanted at energies in the range from 30 keV to 800 keV in amorphous and polycrystalline silicon are analysed. Moments of these distributions are determined by a curve-fitting programme and compared with moments calculated by Winterbon. Boron distributions obtained by implantations along a dense crystallographic direction in monocrystalline silicon are found to have penetrating tails. After investigation of some possible mechanisms of tail formation it is concluded that the tails are due to channelling. It was found that the behaviour of boron during annealing is determined by the properties of three boron fractions consisting of precipitated boron, interstitial boron and substitutional boron. The electrical activity of the boron versus depth is found to be consistent with the three boron fractions. A peculiar redistribution of boron is found which is induced by the implantation of a high dose of heavy ions and subsequent annealing. Different mechanisms which may cause the observed effects, such as thermal diffusion which is influenced by lattice strain and damage, are discussed. (Auth.)

  5. To the question of studying the source base potential from the history of the USSR’s Swedes

    Directory of Open Access Journals (Sweden)

    Kudrytska, T. L.

    2015-05-01

    Full Text Available The article is dedicated to the analyze of the potential sources of information on the history of Swedish USSR. Available sources were divided into legislative acts (record keeping records, materials law enforcement cases, statistical sources, materials of personal origin (memoirs, letters, reports visitors to the village and publications on the pages of local and Swedish media. Using the criteria of reasonable sufficiency, summarized that generated source base study is representative for the study of many aspects of the history of Swedish USSR. It is proved that an official office documents submitted by regulatory and accounting and control documentation have enormous information potential for the reconstruction process of the establishment of Soviet power in rural areas and stages of socio-cultural transformation of the population of the Gammmalsvenksby. It was reflected in a public reaction on the government national policy which was implemented. Based on forensic investigation files it is possible to reconstruct events Stalin’s purges and World War II that took place among Swedes, to follow national specific repression, learn about relationships within the Swedish national minority and their relationships with individual representatives of other nationalities. One of the most important features of this documents their role in the reconstruction of physical and psychological portrait of the defendants, their strategies of behavior in extreme situations. Information capacity of the A. Annas memories provides opportunities to study the history of Soviet Swedes in interwar period, their daily life, economy, behavior strategies in extreme situations, relations with the Soviet authorities and others. Attracting messages travelers helps to trace the mechanism of image formation of the Russian Swedes in their homeland and determine its impact on attitudes to re-emigrants. In process of analysis of complex source it was shown that in most cases one

  6. Enrichment of boron 10

    International Nuclear Information System (INIS)

    Coutinho, C.M.M.; Rodrigues Filho, J.S.R.; Umeda, K.; Echternacht, M.V.

    1990-01-01

    A isotopic separation pilot plant with five ion exchange columns interconnected in series were designed and built in the IEN. The columns are charged with a strong anionic resin in its alkaline form. The boric acid solution is introduced in the separation columns until it reaches a absorbing zone length which is sufficient to obtain the desired boron-10 isotopic concentration. The boric acid absorbing zone movement is provided by the injection of a diluted hydrochloric acid solution, which replace the boric acid throughout the columns. The absorbing zone equilibrium length is proportional to its total length. The enriched boron-10 and the depleted boron are located in the final boundary and in the initial position of the absorbing zones, respectively. (author)

  7. Thermoelectric properties of boron and boron phosphide CVD wafers

    Energy Technology Data Exchange (ETDEWEB)

    Kumashiro, Y.; Yokoyama, T.; Sato, A.; Ando, Y. [Yokohama National Univ. (Japan)

    1997-10-01

    Electrical and thermal conductivities and thermoelectric power of p-type boron and n-type boron phosphide wafers with amorphous and polycrystalline structures were measured up to high temperatures. The electrical conductivity of amorphous boron wafers is compatible to that of polycrystals at high temperatures and obeys Mott`s T{sup -{1/4}} rule. The thermoelectric power of polycrystalline boron decreases with increasing temperature, while that of amorphous boron is almost constant in a wide temperature range. The weak temperature dependence of the thermal conductivity of BP polycrystalline wafers reflects phonon scattering by grain boundaries. Thermal conductivity of an amorphous boron wafer is almost constant in a wide temperature range, showing a characteristic of a glass. The figure of merit of polycrystalline BP wafers is 10{sup -7}/K at high temperatures while that of amorphous boron is 10{sup -5}/K.

  8. Boron analysis for neutron capture therapy using particle-induced gamma-ray emission

    International Nuclear Information System (INIS)

    Nakai, Kei; Yamamoto, Yohei; Okamoto, Emiko; Yamamoto, Tetsuya; Yoshida, Fumiyo; Matsumura, Akira; Yamada, Naoto; Kitamura, Akane; Koka, Masashi; Satoh, Takahiro

    2015-01-01

    The neutron source of BNCT is currently changing from reactor to accelerator, but peripheral facilities such as a dose-planning system and blood boron analysis have still not been established. To evaluate the potential application of particle-induced gamma-ray emission (PIGE) for boron measurement in clinical boron neutron capture therapy, boronophenylalanine dissolved within a cell culture medium was measured using PIGE. PIGE detected 18 μgB/mL f-BPA in the culture medium, and all measurements of any given sample were taken within 20 min. Two hours of f-BPA exposure was required to create a boron distribution image. However, even though boron remained in the cells, the boron on the cell membrane could not be distinguished from the boron in the cytoplasm. - Highlights: • PIGE was evaluated for measuring blood boron concentration during clinical BNCT. • PIGE detected 18 μgB/mL f-BPA in culture medium. • All measurements of any given sample were taken within 20 min. • Two hours of f-BPA exposure is required to create boron distribution image by PIGE. • Boron on the cell membrane could not be distinguished from boron in the cytoplasm.

  9. Narratives or Sources? Active Learning and the Teaching of Ancient Jewish History and Texts

    Science.gov (United States)

    Satlow, Michael L.

    2012-01-01

    During my career, I have regularly taught a survey course on the history of Jews and Judaism in the Persian, Greek, and early Roman periods (ca. 520 BCE-70 CE). Student performance in the course has long concerned and puzzled me. By the end of the course students demonstrated familiarity with the narratives and concepts we covered, but most did…

  10. Reconstruction of burial history, temperature, source rock maturity and hydrocarbon generation in the northwestern Dutch offshore

    NARCIS (Netherlands)

    Abdul Fattah, R.; Verweij, J.M.; Witmans, N.; Veen, J.H. ten

    2012-01-01

    3D basin modelling is used to investigate the history of maturation and hydrocarbon generation on the main platforms in the northwestern part of the offshore area of the Netherlands. The study area covers the Cleaverbank and Elbow Spit Platforms. Recently compiled maps and data are used to build the

  11. Biographical Compilation by as-Safadi Salah al-Din as a Source of the Golden Horde History

    Directory of Open Access Journals (Sweden)

    Zaynuddinov D.R.

    2016-12-01

    Full Text Available Publication and translation into Russian of extracts of sources on the Golden Horde history remains topical issue of contemporary source studies. Research objective: to introduce into academic circulation materials on the Golden Horde history from a previously unknown medieval Arab source. Research materials: Biographical Collection Aʿyān al-ʿAṣrwa-Aʿwān al-Naṣr (Outstanding personalities of this century, and the champions of victory belonging to the pen of the Mamluk historian al-Safadi, Salah al-Din (696 AH / 1297 – 764 GH./1363. Results and novelty of the research: The work was written by the author in Egypt and Syria in the second half of the 14th century, that is, during the heyday of the Golden Horde. It was first published in 1998 in Beirut in six volumes, the latter being composed of indexes. The amount of volume ranges from 685 (Volume 4 to 736 (Vol.1 pages, which makes a total of 3578 pages (without indexes. The novelty of the paper consists in the fact that it introduces for the first time into scholarly circulation Russian translation of biographies of the Golden Horde khans Tokhta and Uzbek, of the Mamluk physician al-Numan, of amir Kusun and Sultan al-Nasir. The article also contains an analysis of the collection as well as translation of certain sections of the work related to the history of Dasht-i Kipchak, together with brief comments. In conclusion, I would like to note that the introduction into the scholarly circulation of Salah al-Din al-Safadi’s biographical collection Aʿyān al-ʿAṣrwa-Aʿwān al-Naṣr will provide a lot of useful information and help to clarify the available data on the history of the Golden Horde.

  12. A critical assessment of boron target compounds for boron neutron capture therapy.

    Science.gov (United States)

    Hawthorne, M Frederick; Lee, Mark W

    2003-01-01

    Boron neutron capture therapy (BNCT) has undergone dramatic developments since its inception by Locher in 1936 and the development of nuclear energy during World War II. The ensuing Cold War spawned the entirely new field of polyhedral borane chemistry, rapid advances in nuclear reactor technology and a corresponding increase in the number to reactors potentially available for BNCT. This effort has been largely oriented toward the eradication of glioblastoma multiforme (GBM) and melanoma with reduced interest in other types of malignancies. The design and synthesis of boron-10 target compounds needed for BNCT was not channeled to those types of compounds specifically required for GBM or melanoma. Consequently, a number of potentially useful boron agents are known which have not been biologically evaluated beyond a cursory examination and only three boron-10 enriched target species are approved for human use following their Investigational New Drug classification by the US Food and Drug Administration; BSH, BPA and GB-10. All ongoing clinical trials with GBM and melanoma are necessarily conducted with one of these three species and most often with BPA. The further development of BNCT is presently stalled by the absence of strong support for advanced compound evaluation and compound discovery driven by recent advances in biology and chemistry. A rigorous demonstration of BNCT efficacy surpassing that of currently available protocols has yet to be achieved. This article discusses the past history of compound development, contemporary problems such as compound classification and those problems which impede future advances. The latter include means for biological evaluation of new (and existing) boron target candidates at all stages of their development and the large-scale synthesis of boron target species for clinical trials and beyond. The future of BNCT is bright if latitude is given to the choice of clinical disease to be treated and if a recognized study

  13. The World of Barilla Taylor: Bringing History to Life through Primary Sources.

    Science.gov (United States)

    Stearns, Liza

    1997-01-01

    Presents a lesson plan using material from a primary source-based curriculum kit titled "The World of Barilla Taylor." The kit uses personal letters, maps, hospital and work records, and other primary sources to document the life of a young woman working in the textile mills in 19th-century Massachusetts. (MJP)

  14. Archival Theory and the Shaping of Educational History: Utilizing New Sources and Reinterpreting Traditional Ones

    Science.gov (United States)

    Glotzer, Richard

    2013-01-01

    Information technology has spawned new evidentiary sources, better retrieval systems for existing ones, and new tools for interpreting traditional source materials. These advances have contributed to a broadening of public participation in civil society (Blouin and Rosenberg 2006). In these culturally unsettled and economically fragile times…

  15. Pangenesis as a source of new genetic information. The history of a now disproven theory.

    Science.gov (United States)

    Bergman, Gerald

    2006-01-01

    Evolution is based on natural selection of existing biological phenotypic traits. Natural selection can only eliminate traits. It cannot create new ones, requiring a theory to explain the origin of new genetic information. The theory of pangenesis was a major attempt to explain the source of new genetic information required to produce phenotypic variety. This theory, advocated by Darwin as the main source of genetic variety, has now been empirically disproved. It is currently a theory mainly of interest to science historians.

  16. Burial history, thermal history and hydrocarbon generation modelling of the Jurassic source rocks in the basement of the Polish Carpathian Foredeep and Outer Carpathians (SE Poland)

    Science.gov (United States)

    Kosakowski, Paweł; Wróbel, Magdalena

    2012-08-01

    Burial history, thermal maturity, and timing of hydrocarbon generation were modelled for the Jurassic source rocks in the basement of the Carpathian Foredeep and marginal part of the Outer Carpathians. The area of investigation was bounded to the west by Kraków, to the east by Rzeszów. The modelling was carried out in profiles of wells: Będzienica 2, Dębica 10K, Góra Ropczycka 1K, Goleszów 5, Nawsie 1, Pławowice E1 and Pilzno 40. The organic matter, containing gas-prone Type III kerogen with an admixture of Type II kerogen, is immature or at most, early mature to 0.7 % in the vitrinite reflectance scale. The highest thermal maturity is recorded in the south-eastern part of the study area, where the Jurassic strata are buried deeper. The thermal modelling showed that the obtained organic matter maturity in the initial phase of the "oil window" is connected with the stage of the Carpathian overthrusting. The numerical modelling indicated that the onset of hydrocarbon generation from the Middle Jurassic source rocks was also connected with the Carpathian thrust belt. The peak of hydrocarbon generation took place in the orogenic stage of the overthrusting. The amount of generated hydrocarbons is generally small, which is a consequence of the low maturity and low transformation degree of kerogen. The generated hydrocarbons were not expelled from their source rock. An analysis of maturity distribution and transformation degree of the Jurassic organic matter shows that the best conditions for hydrocarbon generation occurred most probably in areas deeply buried under the Outer Carpathians. It is most probable that the "generation kitchen" should be searched for there.

  17. A New Boron Analysis Method

    Energy Technology Data Exchange (ETDEWEB)

    Weitman, J; Daaverhoeg, N; Farvolden, S

    1970-07-01

    In connection with fast neutron (n, {alpha}) cross section measurements a novel boron analysis method has been developed. The boron concentration is inferred from the mass spectrometrically determined number of helium atoms produced in the thermal and epithermal B-10 (n, {alpha}) reaction. The relation between helium amount and boron concentration is given, including corrections for self shielding effects and background levels. Direct and diffusion losses of helium are calculated and losses due to gettering, adsorption and HF-ionization in the release stage are discussed. A series of boron determinations is described and the results are compared with those obtained by other methods, showing excellent agreement. The lower limit of boron concentration which can be measured varies with type of sample. In e.g. steel, concentrations below 10-5 % boron in samples of 0.1-1 gram may be determined.

  18. The Baghdad that Was: Using Primary Sources to Teach World History

    Science.gov (United States)

    Schur, Joan Brodsky

    2009-01-01

    That primary source documents have the power to bring the past alive is no news to social studies teachers. What is new in the last 10 years is the number of digitized documents available online that teachers can download and use in their classrooms. Encouraging teachers to utilize this ever-increasing treasure trove of resources was the goal of…

  19. Discrepancies between sources providing the medication histories of acutely hospitalised patients

    DEFF Research Database (Denmark)

    Karkov, Louise Lindved; Schytte-Hansen, Simon; Nørgaard, Lotte Stig

    2010-01-01

    practitioner (GP) and the in-home care provider. A discrepancy was defined as any disagreement or omission of information between the four sources concerning name, form, strength and dose for each drug with which the patient was being treated. Main outcome measure The number of discrepancies between the data...

  20. Sources, classification, and disposal of radioactive wastes: History and legal and regulatory requirements

    International Nuclear Information System (INIS)

    Kocher, D.C.

    1991-01-01

    This report discusses the following topics: (1) early definitions of different types (classes) of radioactive waste developed prior to definitions in laws and regulations; (2) sources of different classes of radioactive waste; (3) current laws and regulations addressing classification of radioactive wastes; and requirements for disposal of different waste classes. Relationship between waste classification and requirements for permanent disposal is emphasized; (4) federal and state responsibilities for radioactive wastes; and (5) distinctions between radioactive wastes produced in civilian and defense sectors

  1. Heavy metals in marine coastal sediments: assessing sources, fluxes, history and trends.

    Science.gov (United States)

    Frignani, Mauro; Bellucci, Luca Giorgio

    2004-01-01

    Examples are presented from the Adriatic Sea, the Ligurian Sea and the Venice Lagoon to illustrate different approaches to the study of anthropogenic metals in marine coastal sediments. These examples refer to studies of areal distribution and transport mechanisms, individuation of the sources, sediment dating, chronology of the fluxes, present and past trends. In particular, some of the findings achieved in studying the Venice Lagoon are discussed from the point of view of anthropogenic changes both in sediment composition and contaminant fluxes.

  2. Eyewitnesses of History: Italian Amateur Cinema as Cultural Heritage and Source for Audiovisual and Media Production

    OpenAIRE

    Simoni, Paolo

    2015-01-01

    abstractThe role of amateur cinema as archival material in Italian media productions has only recently been discovered. Italy, as opposed to other European countries, lacked a local, regional and national policy for the collection and preservation of private audiovisual documents, which led, as a result, to the inaccessibility of the sources. In 2002 the Archivio Nazionale del Film di Famiglia (Italy’s Amateur Film Archive), founded in Bologna by the Home Movies Association, became the refere...

  3. On analgesic and narcotic plants: Pliny and his Greek sources, the history of a complex graft.

    Science.gov (United States)

    Bonet, Valérie

    2014-01-01

    Grafting is an important concept in the study of Pliny the Elder, who is a compiler of written sources. We intend to examine how this grafting works in Pliny's discussion of analgesic and narcotic plants, especially the most famous: opium poppy, henbane, mandrake, and hound's berry. We will study Pliny's use of Greek sources and ask how he took up his predecessors' works while integrating the changes that took place during the centuries in the diagnosis and treatment of pain. This cultural graft remains elusive because we do not have access to all of Pliny's Greek sources. When Pliny speaks about these plants, he sometimes copies out information, adding or removing details, and occasionally makes significant mistakes. The graft was particularly difficult in this case because these analgesic plants were considered so special and poisonous that they were sometimes rejected or even condemned. Nevertheless, we can say that this cultural graft succeeded, despite some obstacles, because Pliny assimilated and adapted these old Greek materials to his own time, society, and project.

  4. Characterizing the hypersiliceous rocks of Belgium used in (pre-)history: a case study on sourcing sedimentary quartzites

    International Nuclear Information System (INIS)

    Veldeman, Isis; Baele, Jean-Marc; De Doncker, H W J A; Goemaere, Eric; Deceukelaire, Marleen; Dusar, Michiel

    2012-01-01

    Tracking raw material back to its extraction source is a crucial step for archaeologists when trying to deduce migration patterns and trade contacts in (pre-)history. Regarding stone artefacts, the main rock types encountered in the archaeological record of Belgium are hypersiliceous rocks. This is a newly introduced category of rock types comprising those rocks made of at least 90% silica. These are strongly silicified quartz sands or sedimentary quartzites, siliceous rocks of chemical and biochemical origin (e.g. flint), very pure metamorphic quartzites and siliceous volcanic rocks (e.g. obsidian). To be able to distinguish between different extraction sources, ongoing research was started to locate possible extraction sources of hypersiliceous rocks and to characterize rocks collected from these sources. Characterization of these hypersiliceous rocks is executed with the aid of optical polarizing microscopy, optical cold cathodoluminescence and scanning-electron microscopy combined with energy-dispersive x-ray spectrometry and with back-scatter electron imaging. In this paper, we focus on various sedimentary quartzites of Paleogene stratigraphical level. (paper)

  5. Analytical developments in the measurements of boron, nitrate, phosphate and sulphate isotopes and case examples of discrimination of nitrogen and sulphur sources in pollution studies

    International Nuclear Information System (INIS)

    Aggarwal, J.; Sheppard, D.S.; Robinson, B.W.

    1998-01-01

    Methods are documented for the analysis of B isotopes, O and N isotopes in nitrates. B isotopes can be measured by negative ion thermal ionisation mass spectrometry. Nitrate is recovered from groundwaters by ion exchange and the resulting silver nitrate combusted for stable isotope gas analysis. Oxygen isotope analysis of phosphates can be determined by generating and analysing CO 2 gas from the combustion of silver phosphate produced from aqueous samples. Sulphate in ground and surface waters can be separated and concentrated by ion exchange and precipitated as barium sulphate. This is reacted with graphite to yield CO 2 and CO, the latter being spark discharged to CO 2 and the total CO 2 measured for oxygen isotope analysis. Barium sulphide from this reaction is converted to silver sulphide which is reacted with cuprous oxide to give SO 2 gas for sulphur isotope measurements. A case study of the semi-rural Manakau area in New Zealand was conducted to see if nitrate isotopes could be used to detect the source of nitrate contamination (groundwater nitrate - 3- N). Nitrogen isotope (+4 to +12 per mille) coupled with oxygen isotope measurements (+5 to +9 per mille) demonstrated that the nitrogen is not sources from fertilisers but from some combination of septic tank and animal waste. For the case study of sulphate isotope use, sulphur and oxygen isotopic compositions of sulphate in river and lake water from seven major catchments of New Zealand were determined. The isotope analyses have allowed the distinction between natural (geological, geothermal and volcanic) and anthropogenic (fertiliser) sulphur sources. (author)

  6. Evidence for multiple polytypes of semiconducting boron carbide (C2B10) from electronic structure

    International Nuclear Information System (INIS)

    Lunca-Popa, Petru; Brand, J I; Balaz, Snjezana; Rosa, Luis G; Boag, N M; Bai Mengjun; Robertson, B W; Dowben, P A

    2005-01-01

    Boron carbides fabricated via plasma enhanced chemical vapour deposition from different isomeric source compounds with the same C 2 B 10 H 12 closo-icosahedral structure result in materials with very different direct (optical) band gaps. This provides compelling evidence for the existence of multiple polytypes of C 2 B 10 boron carbide and is consistent with electron diffraction results

  7. Inductively coupled plasma and ion sources: History and state-of-the-art

    International Nuclear Information System (INIS)

    Hopwood, J.

    1994-01-01

    Over 100 years ago Hittorf first generated an electrodeless ''ring'' discharge by electromagnetic induction and began a 40 year controversy as to the true physical origin of such a discharge. Even Tesla advocated that these plasmas were merely the result of large electrostatic potential differences rather than electric fields induced by high frequency currents. Through clever experiments using crude spark gaps and leyden jars, the inductive nature of the discharge was confirmed in the late 1920's by MacKinnon, thus supporting the theories and experiments of Sir J.J. Thomson, perhaps the most staunch advocate of the induction mechanism. Today the authors routinely exploit the intense plasmas which are generated by induction. In this talk, the characteristics of inductively coupled plasma (ICP) and ion sources will be reviewed and future applications of intense plasma sources will be discussed. The inductively coupled plasma is Joule heated at moderate gas pressures, but the electromagnetic field penetration of these dense plasmas is limited by the plasma skin depth, typically a few millimeters to a few centimeters. The induction plasma is thus edge heated, a fact that constrains uniformity over large areas if helical induction coils are used. Flat, spiral coils may be used to improve uniformity by driving the plasma using a planar geometry. Issues of dimensional and frequency scaling will be discussed as they apply to large diameter sources. Ion beams extracted from ICPs are used for many applications including space propulsion, high power neutral beams, and materials processing. Broad ion beam (∼10 cm) current densities in excess of 100 mA-cm 2 at 100 keV are obtained in pulsed mode operation. Recently, however, more consumer-oriented applications of less intense ICPs are emerging

  8. The “Majmu al-tawarikh” as a Source on the History of the Jochid Ulus.

    Directory of Open Access Journals (Sweden)

    Zh.M. Sabitov

    2017-09-01

    Full Text Available Research objective: To study information about the Golden Horde contained in a historical source called the “Majmu al-tawarikh” and to analyze the information found in that source about the lives of amirs and khans of the Golden Horde. Research materials: The study was conducted on the basis of an analysis of published and unpublished sections of the “Majmu al-tawarikh” which have been translated. Results and novelty of the research: The “Majmu al-tawarikh” is a valuable source for the history of the Golden Horde. There are a number of anachronisms in the “Majmu al-tawarikh”, but it also contains unique and original information about the history of the Golden Horde. There are three copies of the source. The first copy (B 667 is stored at the Institute of Oriental Manuscripts of the Academy of Sciences in St. Petersburg. The second copy (№ 693 is stored in the Oriental department of St. Petersburg State University library. The third copy (№ 167a stored in the fund of the National Academy of Sciences of the Kyrgyz Republic (Bishkek. A translation in Kyrghyz of the third copy was published in 1996. This source contains unique information about the life and family of such khans of the Golden Horde as Toktamysh, Kara-Nogai, Pulad. This work contains stories about the lives of such amirs as Mamai (from the Kiyat tribe, Teginya (Tegin, Dekne from the Shirin tribe, Temir-khodzha (Dair-Khodzha and his son Kara-Khodzha from the Argyn tribe, Hussain Aq-Sufi from Kungirat tribe and his son Ak Nogai, Mamai from the Saray tribe, Baba Ali from the Khitai tribe, etc. Baba Ali from Khitai tribe was the main source of information for “Majmu al-tawarikh” about the Jochid ulus. He served Abd al-Kerim, the khan of Astrakhan, and the Khwarezm’s khan, Sultan-Ghazi. This same Baba Ali was also the informant of Ötemish-Hajji, who recorded stories about Tokhtamysh, Kara-Nogay and Hussain Aq-Sufi.

  9. Neutral mutation as the source of genetic variation in life history traits.

    Science.gov (United States)

    Brcić-Kostić, Krunoslav

    2005-08-01

    The mechanism underlying the maintenance of adaptive genetic variation is a long-standing question in evolutionary genetics. There are two concepts (mutation-selection balance and balancing selection) which are based on the phenotypic differences between alleles. Mutation - selection balance and balancing selection cannot properly explain the process of gene substitution, i.e. the molecular evolution of quantitative trait loci affecting fitness. I assume that such loci have non-essential functions (small effects on fitness), and that they have the potential to evolve into new functions and acquire new adaptations. Here I show that a high amount of neutral polymorphism at these loci can exist in real populations. Consistent with this, I propose a hypothesis for the maintenance of genetic variation in life history traits which can be efficient for the fixation of alleles with very small selective advantage. The hypothesis is based on neutral polymorphism at quantitative trait loci and both neutral and adaptive gene substitutions. The model of neutral - adaptive conversion (NAC) assumes that neutral alleles are not neutral indefinitely, and that in specific and very rare situations phenotypic (relative fitness) differences between them can appear. In this paper I focus on NAC due to phenotypic plasticity of neutral alleles. The important evolutionary consequence of NAC could be the increased adaptive potential of a population. Loci responsible for adaptation should be fast evolving genes with minimally discernible phenotypic effects, and the recent discovery of genes with such characteristics implicates them as suitable candidates for loci involved in adaptation.

  10. Preparation of in-house graphite reference material for boron

    International Nuclear Information System (INIS)

    Kumar, Sanjukta A.; Venkatesh, K.; Swain, Kallola K.; Manisha, V.; Kamble, Granthali S.; Pandey, Shailaja P.; Remya Devi, P.S.; Ghosh, M.; Verma, R.

    2016-05-01

    Graphite is extensively used in nuclear technology. Boron concentration in graphite is one of the important parameters that decide its acceptability for nuclear applications. Reliable analytical methods are essential for the determination of boron in graphite at concentration about 5 mg kg -1 . Reference materials are used for validation of existing analytical methods and developing new methodologies. In view of the importance of determination of boron in graphite and unavailability of graphite reference material, an In-house graphite reference material was prepared in Analytical Chemistry Division. Graphite source material was procured, processed to obtain powder of ≤ 75 μm (200 mesh) and bottled. Procedures were developed for the determination of boron in graphite using inductively coupled plasma optical emission spectrometry (ICPOES) and inductively coupled plasma mass spectrometry (ICPMS) techniques. Homogeneity testing was carried out on the bottled units and boron content along with the combined and expanded uncertainties were established. The assigned boron concentration in the In-house graphite reference material is (7.3±0.46) mg kg -1 . (author)

  11. Structural Modification in Carbon Nanotubes by Boron Incorporation

    Directory of Open Access Journals (Sweden)

    Handuja Sangeeta

    2009-01-01

    Full Text Available Abstract We have synthesized boron-incorporated carbon nanotubes (CNTs by decomposition of ferrocene and xylene in a thermal chemical vapor deposition set up using boric acid as the boron source. Scanning and transmission electron microscopy studies of the synthesized CNT samples showed that there was deterioration in crystallinity and improvement in alignment of the CNTs as the boron content in precursor solution increased from 0% to 15%. Raman analysis of these samples showed a shift of ~7 cm−1in wave number to higher side and broadening of the G band with increasing boron concentration along with an increase in intensity of the G band. Furthermore, there was an increase in the intensity of the D band along with a decrease in its wave number position with increase in boron content. We speculate that these structural modifications in the morphology and microstructure of CNTs might be due to the charge transfer from boron to the graphite matrix, resulting in shortening of the carbon–carbon bonds.

  12. Role of gel dosimeters in boron neutron capture therapy

    International Nuclear Information System (INIS)

    Khajeali, Azim; Farajollahi, Ali Reza; Khodadadi, Roghayeh; Kasesaz, Yaser; Khalili, Assef

    2015-01-01

    Gel dosimeters have acquired a unique status in radiotherapy, especially with the advent of the new techniques in which there is a need for three-dimensional dose measurement with high spatial resolution. One of the techniques in which the use of gel dosimeters has drawn the attention of the researchers is the boron neutron capture therapy. Exploring the history of gel dosimeters, this paper sets out to study their role in the boron neutron capture therapy dosimetric process. - Highlights: • Gel dosimeters have been investigated. • Conventional dosimetric proses of BNCT has been investigated. • Role of gel dosimeters in BNCT has been investigated

  13. Eyewitnesses of History: Italian Amateur Cinema as Cultural Heritage and Source for Audiovisual and Media Production

    Directory of Open Access Journals (Sweden)

    Paolo Simoni

    2015-12-01

    Full Text Available The role of amateur cinema as archival material in Italian media productions has only recently been discovered. Italy, as opposed to other European countries, lacked a local, regional and national policy for the collection and preservation of private audiovisual documents, which led, as a result, to the inaccessibility of the sources. In 2002 the Archivio Nazionale del Film di Famiglia (Italy’s Amateur Film Archive, founded in Bologna by the Home Movies Association, became the reference repository of home movies and amateur cinema, promoting the availability of a cultural heritage that had previously been neglected. Today, it preserves about 5,000 hours of footage, contributes to documentary film productions and acts as a cultural and production center. The impact factor of the Home Movies Archive on the Italian audiovisual scenario and the sustainable perspectives strengthen the awareness that amateur film offers new opportunities to discover and represent the past from a different perspective, the one of an eyewitness “from below”. The article overviews the European and Italian discovery of amateur cinema as historical source from the seventies, and some cases from the Italian panorama during the last fifteen years, which powerfully raised the attention on home movies and amateur archive material.

  14. Development of beryllium-based neutron target system with three-layer structure for accelerator-based neutron source for boron neutron capture therapy.

    Science.gov (United States)

    Kumada, Hiroaki; Kurihara, Toshikazu; Yoshioka, Masakazu; Kobayashi, Hitoshi; Matsumoto, Hiroshi; Sugano, Tomei; Sakurai, Hideyuki; Sakae, Takeji; Matsumura, Akira

    2015-12-01

    The iBNCT project team with University of Tsukuba is developing an accelerator-based neutron source. Regarding neutron target material, our project has applied beryllium. To deal with large heat load and blistering of the target system, we developed a three-layer structure for the target system that includes a blistering mitigation material between the beryllium used as the neutron generator and the copper heat sink. The three materials were bonded through diffusion bonding using a hot isostatic pressing method. Based on several verifications, our project chose palladium as the intermediate layer. A prototype of the neutron target system was produced. We will verify that sufficient neutrons for BNCT treatment are generated by the device in the near future. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Data Science: History repeated? - The heritage of the Free and Open Source GIS community

    Science.gov (United States)

    Löwe, Peter; Neteler, Markus

    2014-05-01

    Data Science is described as the process of knowledge extraction from large data sets by means of scientific methods. The discipline draws heavily from techniques and theories from many fields, which are jointly used to furthermore develop information retrieval on structured or unstructured very large datasets. While the term Data Science was already coined in 1960, the current perception of this field places is still in the first section of the hype cycle according to Gartner, being well en route from the technology trigger stage to the peak of inflated expectations. In our view the future development of Data Science could benefit from the analysis of experiences from related evolutionary processes. One predecessor is the area of Geographic Information Systems (GIS). The intrinsic scope of GIS is the integration and storage of spatial information from often heterogeneous sources, data analysis, sharing of reconstructed or aggregated results in visual form or via data transfer. GIS is successfully applied to process and analyse spatially referenced content in a wide and still expanding range of science areas, spanning from human and social sciences like archeology, politics and architecture to environmental and geoscientific applications, even including planetology. This paper presents proven patterns for innovation and organisation derived from the evolution of GIS, which can be ported to Data Science. Within the GIS landscape, three strategic interacting tiers can be denoted: i) Standardisation, ii) applications based on closed-source software, without the option of access to and analysis of the implemented algorithms, and iii) Free and Open Source Software (FOSS) based on freely accessible program code enabling analysis, education and ,improvement by everyone. This paper focuses on patterns gained from the synthesis of three decades of FOSS development. We identified best-practices which evolved from long term FOSS projects, describe the role of community

  16. Sources, extent and history of methane seepage on the continental shelf off northern Norway

    Science.gov (United States)

    Sauer, Simone; Lepland, Aivo; Chand, Shyam; Schubert, Carsten J.; Eichinger, Florian; Knies, Jochen

    2014-05-01

    Active natural hydrocarbon gas seepage was recently discovered in the Hola area on the continental shelf off Vesterålen, northern Norway. We conducted acoustic and geochemical investigations to assess the modern and past extent, source and pathways of the gas seepage . Water column echosounder surveys showed bubble plumes up to several tens of metres above the seafloor. Analyses of dissolved methane in the water column indicated slightly elevated concentrations (50 nM) close to the seafloor. To identify fluxes and origin of methane in the sediments we analysed sediment pore water chemistry, the isotopic composition of methane and of dissolved inorganic carbon (d13CCH4, d2HCH4, d13CDIC) in three closely spaced (

  17. Boron fertilization on sweet potato: effect of sources, rates and application formAdubação com boro em batata-doce: efeito das fontes, doses e modos de aplicação

    Directory of Open Access Journals (Sweden)

    José Eduardo Creste

    2011-12-01

    Full Text Available Boron (B fertilization can result in high yield and better sweet potato storage roots quality. However, there is few works about this subject. The objective was to evaluate the yield of sweet potato crops in response to B sources, rates and application form. The experimental design was complete randomized blocks, in factorial outline ((2x2x2+1, with three replications, which resulted of the combination of sources of B (boric acid and borax, application form (via soil and via foliar and doses of B (1 and 2 kg ha-1 and a control treatment (without B. There was no interaction between the factors studied for the commercial yield of sweet potato. No significant differences was found between B sources and application form, but they showed higher yield than the control treatment. Additionally, sweet potato yield increade with application of 2 kg ha-1 of B.A adubação boratada pode proporcionar aumentos na produtividade e na qualidade das raízes tuberosas de batata-doce, no entanto poucos trabalhos contemplam esse assunto. Objetivou-se avaliar a produtividade da cultura da batata-doce em resposta a fontes, doses e modos de aplicação de B. O delineamento experimental utilizado foi o de blocos casualizados, em esquema fatorial ((2x2x2+1, com três repetições. Os tratamentos foram aplicados em cobertura, sendo resultados da combinação de fontes de B (ácido bórico e bórax, formas de aplicação (via solo e via foliar e doses de B (1 e 2 kg ha-1 mais uma testemunha. Não houve interação entre os fatores estudados sobre a produtividade comercial de batata-doce. As formas de aplicação, via solo e via foliar bem como as fontes ácido bórico e bórax não apresentaram diferenças entre si, mas proporcionaram produtividades superiores ao tratamento sem B. A produtividade de batata-doce foi favorecida com a aplicação de 2 kg ha-1 de B.

  18. Prediction of broadband ground-motion time histories: Hybrid low/high-frequency method with correlated random source parameters

    Science.gov (United States)

    Liu, P.; Archuleta, R.J.; Hartzell, S.H.

    2006-01-01

    We present a new method for calculating broadband time histories of ground motion based on a hybrid low-frequency/high-frequency approach with correlated source parameters. Using a finite-difference method we calculate low- frequency synthetics (structure. We also compute broadband synthetics in a 1D velocity model using a frequency-wavenumber method. The low frequencies from the 3D calculation are combined with the high frequencies from the 1D calculation by using matched filtering at a crossover frequency of 1 Hz. The source description, common to both the 1D and 3D synthetics, is based on correlated random distributions for the slip amplitude, rupture velocity, and rise time on the fault. This source description allows for the specification of source parameters independent of any a priori inversion results. In our broadband modeling we include correlation between slip amplitude, rupture velocity, and rise time, as suggested by dynamic fault modeling. The method of using correlated random source parameters is flexible and can be easily modified to adjust to our changing understanding of earthquake ruptures. A realistic attenuation model is common to both the 3D and 1D calculations that form the low- and high-frequency components of the broadband synthetics. The value of Q is a function of the local shear-wave velocity. To produce more accurate high-frequency amplitudes and durations, the 1D synthetics are corrected with a randomized, frequency-dependent radiation pattern. The 1D synthetics are further corrected for local site and nonlinear soil effects by using a 1D nonlinear propagation code and generic velocity structure appropriate for the site’s National Earthquake Hazards Reduction Program (NEHRP) site classification. The entire procedure is validated by comparison with the 1994 Northridge, California, strong ground motion data set. The bias and error found here for response spectral acceleration are similar to the best results that have been published by

  19. Deposition of Boron in Possible Evaporite Deposits in Gale Crate

    Science.gov (United States)

    Gasda, P. J.; Peets, E.; Lamm, S. N.; Rapin, W.; Lanza, N.; Frydenvang, J.; Clark, B. C.; Herkenhoff, K. E.; Bridges, J.; Schwenzer, S. P.; Haldeman, E. B.; Wiens, R. C.; Maurice, S.; Clegg, S. M.; Delapp, D.; Sanford, V.; Bodine, M. R.; McInroy, R.

    2017-12-01

    Boron has been previously detected in Gale crater using the ChemCam instrument on board the NASA Curiosity rover within calcium sulfate fracture fill hosted by lacustrine mudstone and eolian sandstone units. Recent results show that up to 300 ppm B is present in the upper sections of the lacustrine unit. Boron has been detected in both the groundwater-emplaced calcium sulfate fracture fill materials and bedding-parallel calcium sulfate layers. The widespread bedding-parallel calcium sulfate layers within the upper strata of the lacustrine bedrock that Curiosity has encountered recently could be interpreted as primary evaporite deposits. We have two hypotheses for the history of boron in Gale crater. In both hypotheses, borates were first deposited as lake water evaporated, depositing primary evaporates that were later re-dissolved by groundwater, which redistributed the boron into secondary evaporitic calcium sulfate fracture fill deposits. In the first scenario, Gale crater may have undergone a period of perennial lake formation during a drier period of martian history, depositing layers of evaporitic minerals (including borates) among lacustrine mudstone layers. In the second scenario, lake margins could have become periodically exposed during cyclic drops in lake level and subsequently desiccated. Evaporites were deposited and desiccation features were formed in lowstand deposits. Either hypothetical scenario of evaporite deposition would promote prebiotic chemical reactions via wet-dry cycles. Boron may be an important prebiotic element, and as such, its presence in ancient martian surface and groundwater provides evidence that important prebiotic chemical reactions could occur on Mars if organics were present. The presence of boron in ancient Gale crater groundwater also provides additional evidence that a habitable environment existed in the martian subsurface well after the expected disappearance of liquid water on the surface of Mars. We will report on the

  20. Boron atom reactions

    International Nuclear Information System (INIS)

    Estes, R.; Tabacco, M.B.; Digiuseppe, T.G.; Davidovits, P.

    1982-01-01

    The reaction rates of atomic boron with various epoxides have been measured in a flow tube apparatus. The bimolecular rate constants, in units of cm 3 molecule -1 s -1 , are: 1,2-epoxypropane (8.6 x 10 -11 ), 1,2-epoxybutane (8.8 x 10 -11 ), 1,2,3,4-diepoxybutane (5.5 x 10 -11 ), 1-chloro-2,3-epoxypropane (5.7 x 10 -11 ), and 1,2-epoxy-3,3,3-trichloropropane (1.5 x 10 -11 ). (orig.)

  1. Biological risk, source and pollution history of organochlorine pesticides (OCPs) in the sediment in Nansha mangrove, South China.

    Science.gov (United States)

    Wu, Qihang; Leung, Jonathan Y S; Yuan, Xin; Huang, Xuexia; Li, Haiyan; Huang, Zhuying; Li, Yang

    2015-07-15

    In the last century, organochlorine pesticides (OCPs) have been extensively used, especially in South China, to promote crop yield. In view of their toxicity, persistence and bioavailability, however, the Chinese government has attempted to regulate their production and use. We aimed to examine the biological risk, source and pollution history of OCPs in the sediment in Nansha mangrove which is located in the industrial region in South China. Results showed that HCHs and DDTs, mainly originating from lindane and technical DDT respectively, were the dominant OCPs, but their concentrations were too low to cause adverse effects on biota. In the last decade, the total concentration of HCHs showed a decreasing trend, whereas DDTs remained stable, despite their limited input. This suggests that management of HCHs was effective, while more management efforts should be put on DDTs, especially the use of dicofol and technical DDT, in future. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Some Details from Eurasian Ethnic History – Altaic Peoples, Chinese Sources and Turania

    Directory of Open Access Journals (Sweden)

    Emil Heršak

    2000-12-01

    Full Text Available In the first part of the paper, the author discusses some details pertaining to the Altaic languages and the location of the Altaic homeland. As to the key question of Altaic theory – i.e. whether Turkic, Mongolic, Tungusic, Korean and Japanese form a genuine language family or separate families linked only through intercontacts and borrowings – he tentatively assumes that there is a distant genetic relationship. On the basis of a reduced list of reconstructed roots, the Proto-Altaic community seems to have been a hunting-fishing and gathering society, with perhaps some scratch farming. Social organisations were clearly patriarchal, with emphasis on age distinctions, and there are also signs of regular warfare and shamanistic activities. Much less explicate are the geographical indications regarding a possible “homeland“ – however, Proto-Altaic appears to have been spoken by a people living in a forested region, with some open fields, access to water sources, primarily in a lowland topography and near certain “badlands“ (sandy zones, salt flats and/or marshes. So far two such areas have been singled out: 1 in the East between the Central Chinese Valley, the Gobi and Manchuria; 2 in the West in the Turanian lowlands. Some researchers have much favoured a Western origin. However – as implied by genetic analysis of living populations – Proto-Altaic groups may well have lived near the Yellow River prior to the extension of the Chinese Neolithic, after which they would have been linguistically assimilated by Sino-Tibetan speakers. Yet the various Gobi cultures of this period also show links with the Turanian area. The author notes that events during the 3rd millennium B.P., including technological and ecological change, probably effected the expansion of the Altaic languages, influencing also the final articulation into various subgroups. In the second part of the paper, he deals with various ethnic groups mentioned in early Chinese

  3. From source to surface: Tracking magmatic boron and chlorine input into the geothermal systems of the Taupo Volcanic Zone, New Zealand

    Science.gov (United States)

    Bégué, Florence; Deering, Chad D.; Gravley, Darren M.; Chambefort, Isabelle; Kennedy, Ben M.

    2017-10-01

    The magmatic contribution into geothermal fluids in the central Taupo Volcanic Zone (TVZ), New Zealand, has been attributed to either andesitic, 'arc-type' fluids, or rhyolitic, 'rift-type' fluids to explain the compositional diversity of discharge waters. However, this model relies on outdated assumptions related to geochemical trends associated with the magma at depth of typical arc to back-arc settings. Current tectonic models have shown that the TVZ is situated within a rifting arc and hosts magmatic systems dominated by distinct rhyolite types, that are likely to have evolved under different conditions than the subordinate andesites. Therefore, a new appraisal of the existing models is required to further understand the origin of the spatial compositional diversity observed in the geothermal fluids and its relationship to the structural setting. Here, we use volatile concentrations (i.e. H2O, Cl, B) from rhyolitic and andesitic mineral-hosted melt inclusions to evaluate the magmatic contribution to the TVZ geothermal systems. The andesite and two different types of rhyolites (R1 and R2) are each distinct in Cl/H2O and B/Cl, which will affect volatile solubility and phase separation (vapor vs. hydrosaline liquid) of the exsolved volatile phase. Ultimately, these key differences in the magmatic volatile constituents will play a significant role in governing the concentration of Cl discharged into geothermal systems. We estimate bulk fluid compositions (B and Cl) in equilibrium with the different melt types to show the potential contribution of 'parent' fluids to the geothermal systems throughout the TVZ. The results of this analysis show that the variability in fluid compositions partly reflects degassing from previously unaccounted for distinct magma source compositions. We suggest the geothermal systems that appear to have an 'arc-type' andesitic fluid contribution are actually derived from a rhyolite melt in equilibrium with a highly crystalline andesite

  4. Confessional Records as a Source of the History of the Pskov Church and Clergy of the 1727-1762

    Directory of Open Access Journals (Sweden)

    Postnikov Arsenii

    2016-12-01

    Full Text Available The task of the article is to introduce of the new mass sources for the research of the Pskov church and clergy into the scientific circulation. The work is based on the Pskov confessional records of the 1727–1762, kept in State Archive of the Pskov Region (SAPR, for the first time raised in full amount for research. The general historiography on the subject as well as history of introduction of the confessional records into church usage are presented in the article. Results of systematization of the confessional records given have afforded to defi ne the cast of the functioning parishes in Pskov. As a whole it was identified 597 confessional records of 57 “Pskov Town” churches for the period of research. They contain the extensive knowledge on the personnel of Church clergy and the number of white clergy in Pskov during the first decades of the synod period in the Russian Orthodox Church history. On their basis it is possible to find out about the time and periods of clergy personnel’s service in every temple, about movements by the “ladder of ranks”, that shows life path of the clergy representatives in the years when there was no service records and clergy accounts, containing biography data. The remarkable feature of the confessional records is that they are the fi rst source to appear by time where with the highest degree of completeness the people “spiritual and their household” were taken into account. There are data given here about all members of the priesthood and clergy families and their age (including female part, that opens the wide opportunities for reconstruction of the clergy representatives’ genealogies and study of the spiritual estate as a whole. Refs 16 names.

  5. Structure and photoluminescence of boron and nitrogen co-doped carbon nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Wang, B.B. [College of Chemistry and Chemical Engineering, Chongqing University of Technology, 69 Hongguang Rd, Lijiatuo, Banan District, Chongqing 400054 (China); Gao, B. [College of Computer Science, Chongqing University, Chongqing 400044 (China); Chongqing Municipal Education Examinations Authority, Chongqing 401147 (China); Zhong, X.X., E-mail: xxzhong@sjtu.edu.cn [Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Shao, R.W.; Zheng, K. [Institute of Microstructure and Properties of Advanced Materials, Beijing University of Technology, Beijing 100124 (China)

    2016-07-15

    Graphical abstract: Boron- and nitrogen- doped carbon nanorods. - Highlights: • The co-doping of nitrogen and boron in carbon nanorods. • The doping mechanism of nitrogen and boron in carbon nanorods by plasma. • Photoluminescence properties of nitrogen- and boron-doped carbon nanorods. - Abstract: Boron and nitrogen doped carbon nanorods (BNCNRs) were synthesized by plasma-enhanced hot filament chemical vapor deposition, where methane, nitrogen and hydrogen were used as the reaction gases and boron carbide was the boron source. The results of scanning electron microscopy, micro-Raman spectroscopy, transmission electron microscopy and X-ray photoelectron spectroscopy indicate that boron and nitrogen can be used as co-dopants in amorphous carbon nanorods. Combined with the characterization results, the doping mechanism was studied. The mechanism is used to explain the formation of different carbon materials by different methods. The photoluminescence (PL) properties of BNCNRs were studied. The PL results show that the BNCNRs generate strong green PL bands and weak blue PL bands, and the PL intensity lowered due to the doping of boron. The outcomes advance our knowledge on the synthesis and optical properties of carbon-based nanomaterials and contribute to the development of optoelectronic nanodevices based on nano-carbon mateirals.

  6. Lithuanian Metrics as a Source on the History of the Turkic States of Eastern Europe »

    Directory of Open Access Journals (Sweden)

    V.V. Trepavlov

    2015-12-01

    Lithuanian Metrica seem to be a necessary element of the source base for the study of the later Golden Horde and ‘post-Horde’ khanates of the 15th–16th centuries (and of the 17th century for Crimea.

  7. Synovectomy by neutron capture in boron

    International Nuclear Information System (INIS)

    Vega C, H.R.

    2002-01-01

    The rheumatoid arthritis is an illness which affect approximately at 3% of the World population. This illness is characterized by the inflammation of the joints which reduces the quality of life and the productivity of the patients. Since, it is an autoimmune illness, the inflammation is due to the overproduction of synovial liquid by the increase in the quantity of synoviocytes. The rheumatoid arthritis does not have a definitive recovery and the patients have three options of treatment: the use of drugs, the surgery and the radio synovectomy. The synovectomy by neutron capture in Boron is a novel proposal of treatment of the rheumatoid arthritis that consists in using a charged compound with Boron 10 that is preferently incorporated in the synoviocytes and to a less extent in the rest of surrounding tissues of the joint. Then, the joint is exposed to a thermal neutron field that induces the reaction (n, α) in the 10 B. the products of this reaction place their energy inside synoviocytes producing their reduction and therefore the reduction of the joint inflammation. Since it is a novel procedure, the synovectomy by neutron capture in boron has two problems: the source design and the design of the adequate drug. In this work it has been realized a Monte Carlo study with the purpose to design a moderating medium that with a 239 Pu Be source in its center, produces a thermal neutron field. With the produced neutron spectra, the neutrons spectra and neutron doses were calculated in different sites inside a model of knee joint. In Monte Carlo studies it is necessary to know the elemental composition of all the joint components, for the case of synovia and the synovial liquid this information does not exist in such way that it is supposed that its composition is equal than the water. In this work also it has been calculated the kerma factors by neutrons of synovia and the synovial liquid supposing that their elemental composition are similar to the blood tissue

  8. Separation process for boron isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Rockwood, S D

    1975-06-12

    The method according to the invention is characterized by the steps of preparing a gaseous mixture of BCl/sub 3/ containing the isotopes of boron and oxygen as the extractor, irradiating that mixture in the tube of the separator device by means of P- or R-lines of a CO/sub 2/ laser for exciting the molecules containing a given isotope of boron, simultaneously irradiating the mixture with UV for photodissociating the excited BCl/sub 3/ molecules and separating BCl/sub 3/ from the reaction products of photodissociation and from oxygen. Such method is suitable for preparing boron used in nuclear reactors.

  9. Lattice dynamics of α boron and of boron carbide

    International Nuclear Information System (INIS)

    Vast, N.

    1999-01-01

    The atomic structure and the lattice dynamics of α boron and of B 4 C boron carbide have been studied by Density Functional Theory (D.F.T.) and Density Functional Perturbation Theory (D.F.P.T.). The bulk moduli of the unit-cell and of the icosahedron have been investigated, and the equation of state at zero temperature has been determined. In α boron, Raman diffusion and infrared absorption have been studied under pressure, and the theoretical and experimental Grueneisen coefficients have been compared. In boron carbide, inspection of the theoretical and experimental vibrational spectra has led to the determination of the atomic structure of B 4 C. Finally, the effects of isotopic disorder have been modeled by an exact method beyond the mean-field approximation, and the effects onto the Raman lines has been investigated. The method has been applied to isotopic alloys of diamond and germanium. (author)

  10. Physiological and genetic basis of plant tolerance to excess boron

    Directory of Open Access Journals (Sweden)

    Kastori Rudolf R.

    2008-01-01

    Full Text Available Boron (B deficit as well as excess may significantly limit the organic production in plants. In extreme cases they may kill the affected plants. Boron excess occurs primarily in arid and semiarid regions, in saline soils or in consequence to human action. Excessive boron concentrations retard plant growth and cause physiological and morphological changes (chlorosis and necrosis first of all in leaf tips and then in marginal or intercostal parts of the lamina. Physiological mechanisms of plant tolerance to boron excess have not been studied in sufficient detail. The predominant opinion holds that they are based on restricted uptake and accumulation of boron in the root and aboveground plant parts. Significant differences in boron excess tolerance have been observed not only between different crops but even between different genotypes of the same crop. This has enabled the breeding of crop genotypes and crops adapted to growing on soils rich in available boron and intensified the research on the inheritance of plant tolerance to high B concentration. Sources of tolerance to high B concentration have been found in many crops (wheat, mustard, pea, lentil, eucalypt. Using different molecular techniques based on PCR (RAPD, SRAP, plant parents and progenies have been analyzed in an attempt to map as precisely as possible the position of B-tolerant genes. Small grains have been studied in greatest detail for inheritance of B tolerance. B tolerance in wheat is controlled by at least four additive genes, Bo1, Bo2, Bo3 and Bo4. Consequently, there exists a broad range of tolerance levels. Studies of Arabidopsis have broadened our understanding of regulation mechanisms of B transport from roots to above ground parts, allowing more direct genetic manipulations.

  11. Nothing Boring About Boron

    Science.gov (United States)

    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

  12. Crossed Molecular Beams Investigations on the Dynamics and Energetics of Elementary Boron Reactions with Unsaturated Hydrocarbons

    National Research Council Canada - National Science Library

    Kaiser, Ralf I

    2006-01-01

    ...). It should be recalled that the AFOSR Grant FA9550-05-1-0124 under which the experiments have been conducted was intended as a starter grant to get the experimental setup complete, the boron source...

  13. Boronization in TEXTOR

    International Nuclear Information System (INIS)

    Winter, J.; Esser, H.G.; Koenen, L.; Reimer, H.; Seggern, J. v.; Schlueter, J.; Waelbroeck, F.; Wienhold, P.; Veprek, S.

    1989-01-01

    The liner and limiters of TEXTOR have been coated in situ with a boron containing carbon film using a RG discharge in a throughflow of 0.8 He + 0.1 B 2 H 6 + 0.1 CH 4 . The average film thickness was 30-50 nm, the ratio of boron and carbon in the layer was about 1:1 according to Auger Electron Spectroscopy. Subsequent tokamak discharges are characterized by a small fraction of radiated power ( eff lower than 1.2 are derived from conductivity measurements. The most prominent change in the impurity concentration compared to good conditions in a carbonized surrounding is measured for oxygen. The value OVI/anti n e of the OVI intensity normalized to the averaged plasma density anti n e decreases by more than a factor of four. The decrease in the oxygen content manifests itself also as a reduction of the CO and CO 2 partial pressures measured during and after the discharge with a sniffer probe. The carbon levels are reduced by a factor of about two as measured by the normalized intensity CII/anti n e of the CII line and via the ratio of the C fluxes and deuterium fluxed measured at the limiter (CI/D α ). The wall shows a pronounced sorption of hydrogen from the plasma, easing the density control and the establishment of low recycling conditions. The beneficial conditions did not show a significant deterioration during more than 200 discharges, including numerous shots at ICRH power levels >2 MW. (orig.)

  14. Note on boron toxicity in oats

    Energy Technology Data Exchange (ETDEWEB)

    Langille, W M; Mahoney, J F

    1959-01-01

    Boron was applied at the rate of 35 pounds per acre of borax to a field of oats. With the first noticeable growth there appeared a definite chlorotic condition of the oat seedlings on plots receiving boron treatments. Analysis of chlorotic tissue at 3 weeks after seeding indicated 110 ppm boron, while apparently healthy tissue contained 6.1 ppm boron at the same stage of growth. There was a rapid decline in the boron content of the oat tissue as the crop grew older. At maturity the oat tissue from the boron-treated plots contained an average of 14.15 ppm boron as compared with 4.10 boron from untreated areas. Boron toxicity had no harmful effect so far as yields were concerned, under the conditions of this experiment. 3 references.

  15. Method for producing polycrystalline boron nitride

    International Nuclear Information System (INIS)

    Alexeevskii, V.P.; Bochko, A.V.; Dzhamarov, S.S.; Karpinos, D.M.; Karyuk, G.G.; Kolomiets, I.P.; Kurdyumov, A.V.; Pivovarov, M.S.; Frantsevich, I.N.; Yarosh, V.V.

    1975-01-01

    A mixture containing less than 50 percent of graphite-like boron nitride treated by a shock wave and highly defective wurtzite-like boron nitride obtained by a shock-wave method is compressed and heated at pressure and temperature values corresponding to the region of the phase diagram for boron nitride defined by the graphite-like compact modifications of boron nitride equilibrium line and the cubic wurtzite-like boron nitride equilibrium line. The resulting crystals of boron nitride exhibit a structure of wurtzite-like boron nitride or of both wurtzite-like and cubic boron nitride. The resulting material exhibits higher plasticity as compared with polycrystalline cubic boron nitride. Tools made of this compact polycrystalline material have a longer service life under impact loads in machining hardened steel and chilled iron. (U.S.)

  16. Metal interactions with boron clusters

    International Nuclear Information System (INIS)

    Grimes, R.N.

    1982-01-01

    This book presents information on the following topics: the structural and bonding features of metallaboranes and metallacarboranes; transition-metal derivatives of nido-boranes and some related species; interactions of metal groups with the octahydrotriborate (1-) anion, B 3 H 8 ; metallaboron cage compounds of the main group metals; closo-carborane-metal complexes containing metal-carbon and metal-boron omega-bonds; electrochemistry of metallaboron cage compounds; and boron clusters with transition metal-hydrogen bonds

  17. Chemical Analysis of Impurity Boron Atoms in Diamond Using Soft X-ray Emission Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Muramatsu, Yasuji; Iihara, Junji; Takebe, Toshihiko; Denlinger, Jonathan D.

    2008-03-29

    To analyze the local structure and/or chemical states of boron atoms in boron-doped diamond, which can be synthesized by the microwave plasma-assisted chemical vapor deposition method (CVD-B-diamond) and the temperature gradient method at high pressure and high temperature (HPT-B-diamond), we measured the soft X-ray emission spectra in the CK and BK regions of B-diamonds using synchrotron radiation at the Advanced Light Source (ALS). X-ray spectral analyses using the fingerprint method and molecular orbital calculations confirm that boron atoms in CVD-B-diamond substitute for carbon atoms in the diamond lattice to form covalent B-C bonds, while boron atoms in HPT-B-diamond react with the impurity nitrogen atoms to form hexagonal boron nitride. This suggests that the high purity diamond without nitrogen impurities is necessary to synthesize p-type B-diamond semiconductors.

  18. B4C solid target boronization of the MST reversed-field pinch

    International Nuclear Information System (INIS)

    Den Hartog, D.J.; Cekic, M.; Fiksel, G.; Hokin, S.A.; Kendrick, R.D.; Prager, S.C.; Stoneking, M.R.

    1992-10-01

    A solid rod of hot-pressed boron carbide is being used as the source of boron during boronization of MST. The most striking result of this procedure is the reduction in oxygen contamination of the plasma (O III radiation, characteristic of oxygen at the edge, falls by about a factor of 3 after boronization.). The radiated power fraction drops to about half its initial value. Particle reflux from the wall is also lowered, making density control simpler. The rod (12.7 mm diameter) is inserted into the edge plasma of normal high-power RFP discharges. B 4 C is ablated from the surface of the rod and deposited in a thin film (a-B/C:H) on the walls and limiters. The energy flux carried by ''superthermal'' (not ''runaway'') electrons at the edge of MST appears to enhance the efficient, non-destructive ablation of the boron carbide rod

  19. The conflicting roles of boron on the radiation response of precipitate-forming austenitic alloys

    International Nuclear Information System (INIS)

    Okita, T.; Sekimura, N.; Garner, F.

    2007-01-01

    Full text of publication follows: Boron is often a deliberately added solute to improve the radiation resistance of austenitic structural alloys, with boron exerting its greatest influence on carbide precipitation. However, boron also a source of helium via transmutation and therefore tends to accelerate the onset of void nucleation. These conflicting contributions of boron with respect to radiation resistance are not easily separated, but are sometimes utilized to mimic fusion-relevant gas generation rates when testing in surrogate fission spectra. In an earlier study the authors demonstrated that in simple model ternary alloys that boron additions tended to homogenize swelling somewhat via increased helium generation but not to exert any significant influence on the total swelling. In these easily swelling alloys void nucleation was not significantly influenced by additional helium or by boron's chemical effect, with boron remaining primarily in solution. In the current study, Fe-15Cr-16Ni-0.25 Ti-0.05C alloys with four levels of natural boron addition (0, 100, 500, 2500 appm) were irradiated side-by-side at ∼400 deg. C in the Fast Flux Test Facility under active temperature control in the Materials Open Test Assembly. Although three sets of irradiation conditions were explored, the boron variation was the only variable operating in each data set. The bulk swelling was measured using an immersion density technique and electron microscopy was employed to determine the details of void, dislocation and precipitate microstructure. It was found that by 100 appm B the strongest and most immediate effect of boron was to reduce swelling at all irradiation conditions explored, but the boron-induced increases in overall helium content were rather small over the 0-100 appm B range. This indicates that boron's primary effect was chemical in nature, expressed via its effect on precipitation. As the boron level was progressively increased, however, there was a reversal in

  20. Boron Fullerenes: A First-Principles Study

    Directory of Open Access Journals (Sweden)

    Gonzalez Szwacki Nevill

    2007-01-01

    Full Text Available AbstractA family of unusually stable boron cages was identified and examined using first-principles local-density functional method. The structure of the fullerenes is similar to that of the B12icosahedron and consists of six crossing double-rings. The energetically most stable fullerene is made up of 180 boron atoms. A connection between the fullerene family and its precursors, boron sheets, is made. We show that the most stable boron sheets are not necessarily precursors of very stable boron cages. Our finding is a step forward in the understanding of the structure of the recently produced boron nanotubes.

  1. Isotopic evidence of boron in precipitation originating from coal burning in Asian continent

    International Nuclear Information System (INIS)

    Sakata, Masahiro; Natsumi, Masahiro; Tani, Yukinori

    2010-01-01

    The boron concentration and isotopic composition (δ 11 B) of precipitation collected from December 2002 to March 2006 at three sites on the Japan Sea coast were measured. Those sites have been considerably affected by the long-range transport of air pollutants from the Asian continent during winter and spring when the airflows from the Asian continent are predominant. The boron concentration in the precipitation increased primarily during winter whereas the δ 11 B decreased during winter or spring. It is assumed that this decrease in δ 11 B is not associated with a Rayleigh distillation process, because the previous δD values of the precipitation collected at a site on the Japan Sea coast did not decrease in the same manner. A weak correlation (r 2 =0.13-0.24, P 11 B and the nonsea-salt sulfate (nss-SO 4 2- )/B ratio at each site, suggesting that boron in the precipitation originate primarily from two sources. The first source, which is characterized by high δ 11 B and nss-SO 4 2- /B=0, is seawater. At the northern site, the enrichment factor for boron in the precipitation relative to seawater approached unity during winter. This implies that much of the boron in the precipitation is derived from unfractionated sea salts rather than gaseous boron evaporated from seawater. The second source is characterized by low δ 11 B and high nss-SO 4 2- /B ratio. Most of the nss-SO 4 2- in the precipitation originates from anthropogenic combustion activities in the Asian continent based on the previous model calculations. Coal accounts for a major portion of the total primary energy supply in China. Moreover, coal enriches boron and represents generally negative δ 11 B values. Hence, we propose that the emission of boron from coal burning is the most likely second source. Thus, boron isotopes may be useful as tracers of coal-burning plumes from the Asian continent. (author)

  2. Neutron Damage in Steels Containing Small Amounts of Boron

    Energy Technology Data Exchange (ETDEWEB)

    Myers, H P

    1961-05-15

    Certain low alloy steels contain small amounts (0.003 to 0.007 w/o) of boron which element contributes to the development of the air hardening properties of these steels. Such steels appear attractive for reactor pressure vessel construction but the question arises whether they will, due to the (n,{alpha}) reaction in boron, be more susceptible to neutron radiation damage than other steels which do not contain boron. We have attempted to estimate the importance of damage arising through boron fission relative to that caused by fast neutrons by assuming that the two sources of damage will be proportional to the numbers of displaced atoms produced in the two processes when no annealing or re combination of defects occurs. Within the approximations used we conclude that in a neutron spectrum which may be represented by an equivalent thermal flux {phi}{sub t} and an equivalent fast flux at 1 MeV of {phi}{sub f}, then D, the ratio of damage to boron fission to that caused by fast neutrons, is D = 4.5 x 10{sup -2} {phi}{sub t}/{phi}{sub f} (for 0. 003 w/o B). For the conditions at the inside of the reactor tank to R3 this would imply D = 1.2 x 10{sup -2} , i.e. if the R3 tank were built with a steel containing 0.003 w/o B then damage due to boron fission would be only {approx} 1 % of that caused by fast neutrons. Further problems with such steels as here discussed are the probability of embrittlement due to the introduction of boron fission fragments lithium and helium and the possibility of a radiation enhanced diffusion of boron which might lead to accentuated slow strain rate embrittlement. We argue that none of these problems should arise. It is concluded that a constructional steel containing 0.003 to 0.007 w/o B should not on this account be more susceptible to radiation damage than other non boron containing steels.

  3. Text-Based Argumentation with Multiple Sources: A Descriptive Study of Opportunity to Learn in Secondary English Language Arts, History, and Science

    Science.gov (United States)

    Litman, Cindy; Marple, Stacy; Greenleaf, Cynthia; Charney-Sirott, Irisa; Bolz, Michael J.; Richardson, Lisa K.; Hall, Allison H.; George, MariAnne; Goldman, Susan R.

    2017-01-01

    This study presents a descriptive analysis of 71 videotaped lessons taught by 34 highly regarded secondary English language arts, history, and science teachers, collected to inform an intervention focused on evidence-based argumentation from multiple text sources. Studying the practices of highly regarded teachers is valuable for identifying…

  4. Phosphors containing boron and metals of Group IIIA and IIIB

    Science.gov (United States)

    Setlur, Anant Achyut; Srivastava, Alok Mani; Comanzo, Holly Ann; Manivannan, Venkatesan

    2006-10-31

    A phosphor comprises: (a) at least a first metal selected from the group consisting of yttrium and elements of lanthanide series other than europium; (b) at least a second metal selected from the group consisting of aluminum, gallium, indium, and scandium; (c) boron; and (d) europium. The phosphor is used in light source that comprises a UV radiation source to convert UV radiation to visible light.

  5. Recent Glacier Recession – a New Source of Postglacial Treeline and Climate History in the Swedish Scandes

    Directory of Open Access Journals (Sweden)

    Lisa Öberg

    2011-12-01

    Full Text Available Climate warming during the past century has imposed recession of glaciers and perennial snow/ice patches along the entire Swedish Scandes. On the newly exposed forefields, subfossil wood remnants are being outwashed from beneath ice and snow bodies. In Scandinavia, this kind of detrital wood is a previously unused source of postglacial vegetation and climate history. The present study reports radiocarbon dates of a set of 78 wood samples, retrieved from three main sites, high above modern treelines and stretching along the Swedish Scandes. In accord with previous studies, pine (Pinus sylvestris colonized early emerging nunataks already during the Late Glacial. Around 9600-9500 cal. yr BP a first massive wave of tree establishment, birch and pine, took place in “empty” glacier cirques. Both species grew 400-600 m above their present-ay treeline position and the summer temperatures may have been 3.5 °C warmer than present. In respons to Neoglacial cooling, treelines of both birch and pine descended until their final disappearance from the record 4400 and 5900 cal. yr BP, respectively. During the entire interval 9600 to 4400 cal. yr BP, birch prospered in a 100-150 broad belt above the uppermost pines. The recent emergence of tree remnants in the current habitats relates to the contemporary episode of climate warming, possibly unprecedented for several past millennia. It is inferred, by an anology with the past, that in a future scenario with summers 3.5 ° warmer than present, the birch treeline may rise by 600 m or so.

  6. Adsorption of boron from boron-containing wastewaters by ion exchange in a continuous reactor

    International Nuclear Information System (INIS)

    Yilmaz, A. Erdem; Boncukcuoglu, Recep; Yilmaz, M. Tolga; Kocakerim, M. Muhtar

    2005-01-01

    In this study, boron removal from boron-containing wastewaters prepared synthetically was investigated. The experiments in which Amberlite IRA 743, boron specific resin was used were carried out in a column reactor. The bed volume of resin, boron concentration, flow rate and temperature were selected as experimental parameters. The experimental results showed that percent of boron removal increased with increasing amount of resin and with decreasing boron concentration in the solution. Boron removal decreased with increasing of flow rate and the effect of temperature on the percent of total boron removal increased the boron removal rate. As a result, it was seen that about 99% of boron in the wastewater could be removed at optimum conditions

  7. Lattice vibrations in α-boron

    International Nuclear Information System (INIS)

    Richter, W.

    1976-01-01

    α-rhombohedral boron is the simplest boron modification, with only 12 atoms per unit cell. The boron atoms are arranged in B 12 icosahedra, which are centered at the lattice points of a primitive rhombohedral lattice. The icosahedra are slightly deformed, as the five-fold symmetry of the ideal icosahedron is incompatible with any crystal structure. The lattice dynamics of α-boron are discussed in terms of the model developed by Weber and Thorpe. (Auth.)

  8. Benefits of Low Boron Core Design Concept for PWR

    Energy Technology Data Exchange (ETDEWEB)

    Daing, Aung Tharn; Kim, Myung Hyun [Kyung Hee University, Yongin (Korea, Republic of)

    2009-10-15

    Nuclear design study was carried out to develop low boron core (LBC) based on one of current PWR concepts, OPR-1000. Most of design parameters were the same with those of Ulchin unit-5 except extensive utilization of burnable poison (BP) pins in order to compensate reactivity increase in LBC. For replacement of reduced soluble boron concentration, four different kinds of integral burnable absorbers (IBAs) such as gadolinia, integral fuel burnable absorber (IFBA), erbia and alumina boron carbide were considered in suppressing more excess reactivity. A parametric study was done to find the optimal core options from many design candidates for fuel assemblies and cores. Among them, the most feasible core design candidate was chosen in accordance with general design requirements. In this paper, the feasibility and design change benefits of the most favorable LBC design were investigated in more detail through the comparison of neutronic and thermal hydraulic design parameters of LBC with the reference plant (REF). As calculation tools, the HELIOS/MASTER code package and the MATRA code were utilized. The main purpose of research herein is to estimate feasibility and capability of LBC which was mainly designed to mitigate boron dilution accident (BDA), and for reduction of corrosion products. The LBC design concept using lower boron concentration with an elevated enrichment in {sup 10}B allows a reduction in the concentration of lithium in the primary coolant required to maintain the optimum coolant pH. All in all, LBC with operation at optimum pH is expected to achieve some benefits from radiation source reduction of reduced corrosion product, the limitation of the Axial Offset Anomaly (AOA) and fuel cladding corrosion. Additionally, several merits of LBC are closely related to fluid systems and system related aspects, reduced boron and lithium costs, equipment size reduction for boric acid systems, elimination of heat tracing, and more aggressive fuel design concepts.

  9. Benefits of Low Boron Core Design Concept for PWR

    International Nuclear Information System (INIS)

    Daing, Aung Tharn; Kim, Myung Hyun

    2009-01-01

    Nuclear design study was carried out to develop low boron core (LBC) based on one of current PWR concepts, OPR-1000. Most of design parameters were the same with those of Ulchin unit-5 except extensive utilization of burnable poison (BP) pins in order to compensate reactivity increase in LBC. For replacement of reduced soluble boron concentration, four different kinds of integral burnable absorbers (IBAs) such as gadolinia, integral fuel burnable absorber (IFBA), erbia and alumina boron carbide were considered in suppressing more excess reactivity. A parametric study was done to find the optimal core options from many design candidates for fuel assemblies and cores. Among them, the most feasible core design candidate was chosen in accordance with general design requirements. In this paper, the feasibility and design change benefits of the most favorable LBC design were investigated in more detail through the comparison of neutronic and thermal hydraulic design parameters of LBC with the reference plant (REF). As calculation tools, the HELIOS/MASTER code package and the MATRA code were utilized. The main purpose of research herein is to estimate feasibility and capability of LBC which was mainly designed to mitigate boron dilution accident (BDA), and for reduction of corrosion products. The LBC design concept using lower boron concentration with an elevated enrichment in 10 B allows a reduction in the concentration of lithium in the primary coolant required to maintain the optimum coolant pH. All in all, LBC with operation at optimum pH is expected to achieve some benefits from radiation source reduction of reduced corrosion product, the limitation of the Axial Offset Anomaly (AOA) and fuel cladding corrosion. Additionally, several merits of LBC are closely related to fluid systems and system related aspects, reduced boron and lithium costs, equipment size reduction for boric acid systems, elimination of heat tracing, and more aggressive fuel design concepts

  10. Did the Vikings Really Have Helmets with Horns? Sources and Narrative Content in Swedish Upper Primary School History Teaching

    Science.gov (United States)

    Stolare, Martin

    2017-01-01

    The topic of this article is history education in upper primary school. Traditionally, the history subject has had a narrative orientation at this school level in Sweden, but it is also pattern that is discernible internationally. The recent Swedish upper primary school syllabus places more emphasis on the procedural aspects of the subject. In…

  11. New Icosahedral Boron Carbide Semiconductors

    Science.gov (United States)

    Echeverria Mora, Elena Maria

    Novel semiconductor boron carbide films and boron carbide films doped with aromatic compounds have been investigated and characterized. Most of these semiconductors were formed by plasma enhanced chemical vapor deposition. The aromatic compound additives used, in this thesis, were pyridine (Py), aniline, and diaminobenzene (DAB). As one of the key parameters for semiconducting device functionality is the metal contact and, therefore, the chemical interactions or band bending that may occur at the metal/semiconductor interface, X-ray photoemission spectroscopy has been used to investigate the interaction of gold (Au) with these novel boron carbide-based semiconductors. Both n- and p-type films have been tested and pure boron carbide devices are compared to those containing aromatic compounds. The results show that boron carbide seems to behave differently from other semiconductors, opening a way for new analysis and approaches in device's functionality. By studying the electrical and optical properties of these films, it has been found that samples containing the aromatic compound exhibit an improvement in the electron-hole separation and charge extraction, as well as a decrease in the band gap. The hole carrier lifetimes for each sample were extracted from the capacitance-voltage, C(V), and current-voltage, I(V), curves. Additionally, devices, with boron carbide with the addition of pyridine, exhibited better collection of neutron capture generated pulses at ZERO applied bias, compared to the pure boron carbide samples. This is consistent with the longer carrier lifetimes estimated for these films. The I-V curves, as a function of external magnetic field, of the pure boron carbide films and films containing DAB demonstrate that significant room temperature negative magneto-resistance (> 100% for pure samples, and > 50% for samples containing DAB) is possible in the resulting dielectric thin films. Inclusion of DAB is not essential for significant negative magneto

  12. Boron steel. I Part. Preparation

    International Nuclear Information System (INIS)

    Jaraiz Franco, E.; Esteban Hernandez, J. A.

    1960-01-01

    With the advent of the first nuclear reactors arise the need for control rods and shielding duties for some types of radiations. One of the materials used for this purpose has been the high boron steel. This paper describes the melting and casting procedures employed for the production, at laboratory scale, of steels with Boron content ranging from 1 to 4 per cent, as well as the metallographic and X-Ray techniques used for the identification of the present phases. The electrolytic technique employed for the isolation of the Fe 2 B phase and its subsequent X-Ray identification has proved to be satisfactory. (Author) 11 refs

  13. Chemical separation of boron isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Palko, A.A.

    1978-06-01

    This is the final report of the research performed at ORNL on the chemical fractionation of boron isotopes between BF/sub 3/ gas and the liquid molecular addition compounds of BF/sub 3/. Thirty compounds were studied, ten of them in detail. Graphs and equations are given for variation of isotopic equilibrium constant, vapor pressure, and BF/sub 3/ solubility as a function of temperature. Rate of isotopic exchange and melting points were determined. Several of the compounds are likely candidates for use in a gas-liquid countercurrent exchange system for large-scale separation of boron isotopes. 23 figs, 53 tables, 39 references.

  14. Chemical separation of boron isotopes

    International Nuclear Information System (INIS)

    Palko, A.A.

    1978-06-01

    This is the final report of the research performed at ORNL on the chemical fractionation of boron isotopes between BF 3 gas and the liquid molecular addition compounds of BF 3 . Thirty compounds were studied, ten of them in detail. Graphs and equations are given for variation of isotopic equilibrium constant, vapor pressure, and BF 3 solubility as a function of temperature. Rate of isotopic exchange and melting points were determined. Several of the compounds are likely candidates for use in a gas-liquid countercurrent exchange system for large-scale separation of boron isotopes. 23 figs, 53 tables, 39 references

  15. Sources

    International Nuclear Information System (INIS)

    Duffy, L.P.

    1991-01-01

    This paper discusses the sources of radiation in the narrow perspective of radioactivity and the even narrow perspective of those sources that concern environmental management and restoration activities at DOE facilities, as well as a few related sources. Sources of irritation, Sources of inflammatory jingoism, and Sources of information. First, the sources of irritation fall into three categories: No reliable scientific ombudsman to speak without bias and prejudice for the public good, Technical jargon with unclear definitions exists within the radioactive nomenclature, and Scientific community keeps a low-profile with regard to public information. The next area of personal concern are the sources of inflammation. This include such things as: Plutonium being described as the most dangerous substance known to man, The amount of plutonium required to make a bomb, Talk of transuranic waste containing plutonium and its health affects, TMI-2 and Chernobyl being described as Siamese twins, Inadequate information on low-level disposal sites and current regulatory requirements under 10 CFR 61, Enhanced engineered waste disposal not being presented to the public accurately. Numerous sources of disinformation regarding low level radiation high-level radiation, Elusive nature of the scientific community, The Federal and State Health Agencies resources to address comparative risk, and Regulatory agencies speaking out without the support of the scientific community

  16. Radiological analysis of plutonium glass batches with natural/enriched boron

    International Nuclear Information System (INIS)

    Rainisch, R.

    2000-01-01

    The disposition of surplus plutonium inventories by the US Department of Energy (DOE) includes the immobilization of certain plutonium materials in a borosilicate glass matrix, also referred to as vitrification. This paper addresses source terms of plutonium masses immobilized in a borosilicate glass matrix where the glass components include both natural boron and enriched boron. The calculated source terms pertain to neutron and gamma source strength (particles per second), and source spectrum changes. The calculated source terms corresponding to natural boron and enriched boron are compared to determine the benefits (decrease in radiation source terms) for to the use of enriched boron. The analysis of plutonium glass source terms shows that a large component of the neutron source terms is due to (a, n) reactions. The Americium-241 and plutonium present in the glass emit alpha particles (a). These alpha particles interact with low-Z nuclides like B-11, B-10, and O-17 in the glass to produce neutrons. The low-Z nuclides are referred to as target particles. The reference glass contains 9.4 wt percent B 2 O 3 . Boron-11 was found to strongly support the (a, n) reactions in the glass matrix. B-11 has a natural abundance of over 80 percent. The (a, n) reaction rates for B-10 are lower than for B-11 and the analysis shows that the plutonium glass neutron source terms can be reduced by artificially enriching natural boron with B-10. The natural abundance of B-10 is 19.9 percent. Boron enriched to 96-wt percent B-10 or above can be obtained commercially. Since lower source terms imply lower dose rates to radiation workers handling the plutonium glass materials, it is important to know the achievable decrease in source terms as a result of boron enrichment. Plutonium materials are normally handled in glove boxes with shielded glass windows and the work entails both extremity and whole-body exposures. Lowering the source terms of the plutonium batches will make the handling

  17. Two-channel neutron boron meter

    International Nuclear Information System (INIS)

    Chen Yongqing; Yin Guowei; Chai Songshan; Deng Zhaoping; Zhou Bin

    1993-09-01

    The two-channel neutron boron meter is a continuous on-line measuring device to measure boron concentration of primary cooling liquid of reactors. The neutron-leakage-compensation method is taken in the measuring mechanism. In the primary measuring configuration, the mini-boron-water annulus and two-channel and central calibration loop are adopted. The calibration ring and constant-temperature of boron-water can be remotely controlled by secondary instruments. With the microcomputer data processing system the boron concentration is automatically measured and calibrated in on-line mode. The meter has many advantages such as high accuracy, fast response, multi-applications, high reliability and convenience

  18. Boron-enhanced diffusion of boron from ultralow-energy boron implantation

    International Nuclear Information System (INIS)

    Agarwal, A.; Eaglesham, D.J.; Gossmann, H.J.; Pelaz, L.; Herner, S.B.; Jacobson, D.C.

    1998-01-01

    The authors have investigated the diffusion enhancement mechanism of BED (boron enhanced diffusion), wherein the boron diffusivity is enhanced three to four times over the equilibrium diffusivity at 1,050 C in the proximity of a silicon layer containing a high boron concentration. It is shown that BED is associated with the formation of a fine-grain polycrystalline silicon boride phase within an initially amorphous Si layer having a high B concentration. For 0.5 keV B + , the threshold implantation dose which leads to BED lies between 3 x 10 14 and of 1 x 10 15 /cm -2 . Formation of the shallowest possible junctions by 0.5 keV B + requires that the implant dose be kept lower than this threshold

  19. The Research Seminar “New Sources on the Medieval Turkic-Tatar History: New Findings, Interpretation, Prospects for Research” (Kazan, December 6, 2017

    Directory of Open Access Journals (Sweden)

    L.S. Giniyatullina

    2018-03-01

    Full Text Available The research seminar “New Sources on the Medieval Turkic-Tatar History: New Findings, Interpretation, Prospects for Research” was held at the Sh. Marjani Institute of History of Tatarstan Academy of Sciences on December 6, 2017 in the framework of the International Scientific and Practical Conference, “The Epoch through the Person’s Prism: 130th Anniversary of Gaziz Gubaidullin”. The head of the M.A. Usmanov Center for Research of the Golden Horde and the Tatar Khanate (Sh. Marjani Institute of History of the Tatarstan Academy of Sciences, I.M. Mirgaleev, acted as the coordinator of the seminar and spoke about the importance of studying new sources on medieval Turkic-Tatar history and introducing them into current scholarly discussions. Scholars from academic centers of Russia, Great Britain, and Finland took part in the seminar. Doctor of Historical Studies, Ilya Vladimirovich Zaitsev, acted as its main spea­ker. His speech was devoted to the recently discovery of the “History of Chinggis Khan” by Mansur ibn Abdarrakhman (1741. I.V. Zaitsev described the biography of the author, the history of the creation, and the present study of this work. The next meeting of the editorial board of the research journal, “Golden Horde Review”, was held on the same day, where the following issues related to the development of the journal’s activities were discussed: – the work of the editorial board; – peer review problems; – increasing the proportion of English articles; – unification of bibliographic format. The editor-in-chief, I.M. Mirgaleev, briefly acquainted colleagues with activities of the journal’s editorial board and discussed the successful inclusion of the journal in the citation databases Scopus and WoS, as well as in the list of the Higher Attestation Commission.

  20. Electronic response of a photodiode coupled to a boron thin film

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Priscila; Costa, Fabio E.; Raele, Marcus P.; Zahn, Guilherme S.; Geraldo, Bianca; Vieira Junior, Nilson D.; Samad, Ricardo E.; Genezini, Frederico A., E-mail: priscila3.costa@usp.br, E-mail: fredzini@ipen.br [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil)

    2017-07-01

    A portable thermal neutron detector is proposed in this work using a silicon photodiode coupled to a boron thin film. The aim of this work was to verify the effect in the electronic response of this specific photodiode due to boron deposition, since the direct deposition of boron in the semiconductor surface could affect its electrical properties specifically the p-type layer that affects directly the depletion region of the semiconductor reducing the neutron detector efficiency count. Three boron depositions with different thickness were performed in the photodiode (S3590-09) surface by pulsed laser deposition and the photodiode was characterized, before and after the deposition process, using a radioactive americium source. Energy spectra were used to verify the electronic response of the photodiode, due to the fact that it is possible to relate it to the photopeak pulse height and resolution. Spectra from the photodiode without and with boron film deposition were compared and a standard photodiode (S3590-04) that had the electronic signal conserved was used as reference to the pulse height for electronics adjustments. The photopeak energy resolution for the photodiode without boron layer was 10.26%. For the photodiode with boron deposition at different thicknesses, the resolution was: 7.64 % (0.14 μm), 7.30 % (0.44 μm) and 6.80 % (0.63 μm). From these results it is possible to evaluate that there was not any degradation in the silicon photodiode. (author)

  1. Acute and chronic toxicity of boron to a variety of freshwater organisms.

    Science.gov (United States)

    Soucek, David J; Dickinson, Amy; Koch, Brian T

    2011-08-01

    Boron enters the aquatic environment from various sources, including weathering of borates, sewage effluents, coal combustion, use of cleaning compounds, and agrochemicals. The present study was designed to generate data on acute and chronic boron toxicity in support of an update of water quality standards in Illinois, USA. We examined the acute toxicity of boron to eight different freshwater organisms including a fish, an insect, two crustaceans, and four bivalve mollusks. To our knowledge, this is the first study to present data on the toxicity of boron to freshwater mollusks. We also sought to clarify whether hardness or pH affect boron toxicity to aquatic life, and to quantify chronic effect levels in two freshwater species. Sensitivity among the various species ranged widely, with the fathead minnow (Pimephales promelas) being the most sensitive. Neither pH nor hardness had a consistent effect on acute boron toxicity to two crustaceans (Ceriodaphnia dubia and Hyalella azteca), but we observed evidence that chloride reduces boron toxicity to H. azteca. The fathead minnow, while more acutely sensitive than the other species, had a lower acute to chronic ratio than did H. azteca, which had reduced reproduction at 13 mg/L. While we do not know the extent to which the eight tested species represent the range of sensitivities of native but untested species in Illinois, the current water quality standard for Illinois (1 mg/L) is conservative with regard to the native species tested thus far. Copyright © 2011 SETAC.

  2. The All Boron Carbide Diode Neutron Detector: Experiment and Modeling Approach

    International Nuclear Information System (INIS)

    Sabirianov, Ildar F.; Brand, Jennifer I.; Fairchild, Robert W.

    2008-01-01

    Boron carbide diode detectors, fabricated from two different polytypes of semiconducting boron carbide, will detect neutrons in reasonable agreement with theoretical expectations. The performance of the all boron carbide neutron detector differs, as expected, from devices where a boron rich neutron capture layer is distinct from the diode charge collection region (i.e. a conversion layer solid state detector). Diodes were fabricated from natural abundance boron (20% 10 B and 80% 11 B.) directly on the metal substrates and metal contacts applied to the films as grown. The total boron depth was on the order of 2 microns. This is clearly not a conversion-layer configuration. The diodes were exposed to thermal neutrons generated from a paraffin moderated plutonium-beryllium source in moderated and un-moderated, as well as shielded and unshielded experimental configurations, where the expected energy peaks at at 2.31 MeV and 2.8 MeV were clearly observed, albeit with some incomplete charge collection typical of thinner diode structures. The results are compared with other boron based thin film detectors and literature models. (authors)

  3. Structural characterization of electrodeposited boron

    Indian Academy of Sciences (India)

    Structural characterization of electrodeposited boron was carried out by using transmission electron microscopy and Raman spectroscopy. Electron diffraction and phase contrast imaging were carried out by using transmission electron microscopy. Phase identification was done based on the analysis of electron diffraction ...

  4. Structural characterization of electrodeposited boron

    Indian Academy of Sciences (India)

    high temperature reaction between elemental boron and car- bon to form B4C is .... cible was used as the container for the electrolyte and also acted as an anode. ... chosen as cathode due to its availability, low cost, ease of fabrication and ...

  5. sources

    Directory of Open Access Journals (Sweden)

    Shu-Yin Chiang

    2002-01-01

    Full Text Available In this paper, we study the simplified models of the ATM (Asynchronous Transfer Mode multiplexer network with Bernoulli random traffic sources. Based on the model, the performance measures are analyzed by the different output service schemes.

  6. History-Based Instruction Enriched with Various Sources of Situational Interest on the Topic of the Atom: the Effect on Students' Achievement and Interest

    Science.gov (United States)

    Pekdağ, Bülent; Azizoğlu, Nursen

    2018-05-01

    This study examines the effect of history-based instruction on the topic of the atom on students' academic achievement and their interest in the history of science, investigating as well the relationship between student interest and academic achievement. The sample of the study consisted of two groups of freshman students from an undergraduate elementary science teachers program. The same chemistry instructor taught the groups, which were randomly assigned as an experimental and a control group. The students in the control group received traditional teacher-centered instruction, while the experimental group students were taught the topic of the atom using history-based instruction enriched with various sources of situational interest such as novelty, autonomy, social involvement, and knowledge acquisition (NASK). Data gathering instruments were the Atom Achievement Test and the History of Science Interest Scale, administered to both of the groups before and after the instruction. The data were analyzed with the independent-samples t test, the paired-samples t test, and one-way ANCOVA statistical analysis. The results showed that the history-based instruction including NASK was more effective than traditional instruction in improving the students' learning of the subject of the atom as well as in stimulating and improving students' interest in the history of science. Further, students with high interest displayed significantly better achievement than students with low interest. The better learning of the topic of the atom was more pronounced in the case of students with a high interest in the history of science compared to students with moderate or low interest.

  7. Boron-11 MRI and MRS of intact animals infused with a boron neutron capture agent

    International Nuclear Information System (INIS)

    Kabalka, G.W.; Davis, M.; Bendel, P.

    1988-01-01

    Boron neutron capture therapy (BNCT) depends on the delivery of boron-containing drugs to a targeted lesion. Currently, the verification and quantification of in vivo boron content is a difficult problem. Boron-11 spectroscopy was utilized to confirm the presence of a dimeric sulfhydryl dodecaborane BNCT agent contained in an intact animal. Spectroscopy experiments revealed that the decay time of transverse magnetization of the boron-11 spins was less than 1 ms which precluded the use of a 2DFT imaging protocol. A back-projection protocol was developed and utilized to generate the first boron-11 image of a BNCT agent in the liver of an intact Fisher 344 rat

  8. Friction anisotropy in boronated graphite

    International Nuclear Information System (INIS)

    Kumar, N.; Radhika, R.; Kozakov, A.T.; Pandian, R.; Chakravarty, S.; Ravindran, T.R.; Dash, S.; Tyagi, A.K.

    2015-01-01

    Graphical abstract: - Highlights: • Friction anisotropy in boronated graphite is observed in macroscopic sliding condition. • Low friction coefficient is observed in basal plane and becomes high in prismatic direction. • 3D phase of boronated graphite transformed into 2D structure after friction test. • Chemical activity is high in prismatic plane forming strong bonds between the sliding interfaces. - Abstract: Anisotropic friction behavior in macroscopic scale was observed in boronated graphite. Depending upon sliding speed and normal loads, this value was found to be in the range 0.1–0.35 in the direction of basal plane and becomes high 0.2–0.8 in prismatic face. Grazing-incidence X-ray diffraction analysis shows prominent reflection of (0 0 2) plane at basal and prismatic directions of boronated graphite. However, in both the wear tracks (1 1 0) plane become prominent and this transformation is induced by frictional energy. The structural transformation in wear tracks is supported by micro-Raman analysis which revealed that 3D phase of boronated graphite converted into a disordered 2D lattice structure. Thus, the structural aspect of disorder is similar in both the wear tracks and graphite transfer layers. Therefore, the crystallographic aspect is not adequate to explain anisotropic friction behavior. Results of X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy shows weak signature of oxygen complexes and functional groups in wear track of basal plane while these species dominate in prismatic direction. Abundance of these functional groups in prismatic plane indicates availability of chemically active sites tends to forming strong bonds between the sliding interfaces which eventually increases friction coefficient

  9. Friction anisotropy in boronated graphite

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, N., E-mail: niranjan@igcar.gov.in [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam (India); Radhika, R. [Crystal Growth Centre, Anna University, Chennai (India); Kozakov, A.T. [Research Institute of Physics, Southern Federal University, Rostov-on-Don (Russian Federation); Pandian, R. [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam (India); Chakravarty, S. [UGC-DAE CSR, Kalpakkam (India); Ravindran, T.R.; Dash, S.; Tyagi, A.K. [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam (India)

    2015-01-01

    Graphical abstract: - Highlights: • Friction anisotropy in boronated graphite is observed in macroscopic sliding condition. • Low friction coefficient is observed in basal plane and becomes high in prismatic direction. • 3D phase of boronated graphite transformed into 2D structure after friction test. • Chemical activity is high in prismatic plane forming strong bonds between the sliding interfaces. - Abstract: Anisotropic friction behavior in macroscopic scale was observed in boronated graphite. Depending upon sliding speed and normal loads, this value was found to be in the range 0.1–0.35 in the direction of basal plane and becomes high 0.2–0.8 in prismatic face. Grazing-incidence X-ray diffraction analysis shows prominent reflection of (0 0 2) plane at basal and prismatic directions of boronated graphite. However, in both the wear tracks (1 1 0) plane become prominent and this transformation is induced by frictional energy. The structural transformation in wear tracks is supported by micro-Raman analysis which revealed that 3D phase of boronated graphite converted into a disordered 2D lattice structure. Thus, the structural aspect of disorder is similar in both the wear tracks and graphite transfer layers. Therefore, the crystallographic aspect is not adequate to explain anisotropic friction behavior. Results of X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy shows weak signature of oxygen complexes and functional groups in wear track of basal plane while these species dominate in prismatic direction. Abundance of these functional groups in prismatic plane indicates availability of chemically active sites tends to forming strong bonds between the sliding interfaces which eventually increases friction coefficient.

  10. Alphabetics: A History of Our Alphabet. A Source Guide for Self-Directed Units. Great Ideas Series. Revised Edition.

    Science.gov (United States)

    Patton, Sally J.

    This teaching resource presents a historical perspective of the alphabet which encompasses a study of major contributions by: (1) "Prehistoric People"; (2) "The Sumerians"; (3) "The Egyptians"; (4) "The Chinese"; (5) "The Greeks"; and (6) "The Romans." Background information, vocabulary study, student activities, a letter history, and a…

  11. Reading and Writing from Multiple Source Documents in History: Effects of Strategy Instruction with Low to Average High School Writers

    Science.gov (United States)

    De La Paz, Susan; Felton, Mark K.

    2010-01-01

    This study examined the effects of historical reasoning strategy instruction on 11th-grade students. Students learned historical inquiry strategies using 20th Century American history topics ranging from the Spanish-American war to the Gulf of Tonkin incident. In addition, students learned a pre-writing strategy for composing argumentative essays…

  12. A novel method for boron determination in rock thin sections : first results from Ngawha

    International Nuclear Information System (INIS)

    Vickridge, I.C.

    1994-01-01

    Previous studies of boron in New Zealand rock have relied on whole rock analyses. In order to gain more detailed knowledge of the sources of boron in rocks, we have developed a nuclear probe technique based on the 1 1B(p,α) nuclear reaction. The technique performs well on powdered USGS standards down to below 10 wt. ppm, and we have applied it with a proton beam focused down to 25 x 25 micrometre on a hydrothermally unaltered greywacke from Puketona, near Ngawha, Northland. There appears to be little variation in the boron concentrations in the sedimentary groundmass, but in the veins the boron appears to be more concentrated in the prehnite than in the quartz. (author). 2 tabs., 5 figs., 14 refs

  13. Helium diffusion in irradiated boron carbide

    International Nuclear Information System (INIS)

    Hollenberg, G.W.

    1981-03-01

    Boron carbide has been internationally adopted as the neutron absorber material in the control and safety rods of large fast breeder reactors. Its relatively large neutron capture cross section at high neutron energies provides sufficient reactivity worth with a minimum of core space. In addition, the commercial availability of boron carbide makes it attractive from a fabrication standpoint. Instrumented irradiation experiments in EBR-II have provided continuous helium release data on boron carbide at a variety of operating temperatures. Although some microstructural and compositional variations were examined in these experiments most of the boron carbide was prototypic of that used in the Fast Flux Test Facility. The density of the boron carbide pellets was approximately 92% of theoretical. The boron carbide pellets were approximately 1.0 cm in diameter and possessed average grain sizes that varied from 8 to 30 μm. Pellet centerline temperatures were continually measured during the irradiation experiments

  14. Primary system boron dilution analysis

    International Nuclear Information System (INIS)

    Crump, R.J.; Naretto, C.J.; Borgen, R.A.; Rockhold, H.C.

    1978-01-01

    The results are presented for an analysis conducted to determine the potential paths through which nonborated water or water with insufficient boron concentration might enter the LOFT primary coolant piping system or reactor vessel to cause dilution of the borated primary coolant water. No attempt was made in the course of this analysis to identify possible design modifications nor to suggest changes in administrative procedures or controls

  15. Boron removal from geothermal waters by electrocoagulation

    Energy Technology Data Exchange (ETDEWEB)

    Yilmaz, A. Erdem [Atatuerk University, Faculty of Engineering, Department of Environmental Engineering., 25240 Erzurum (Turkey)], E-mail: aerdemy@atauni.edu.tr; Boncukcuoglu, Recep [Atatuerk University, Faculty of Engineering, Department of Environmental Engineering., 25240 Erzurum (Turkey); Kocakerim, M. Muhtar [Atatuerk University, Faculty of Engineering, Department of Chemical Engineering, 25240 Erzurum (Turkey); Yilmaz, M. Tolga; Paluluoglu, Cihan [Atatuerk University, Faculty of Engineering, Department of Environmental Engineering., 25240 Erzurum (Turkey)

    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{sup 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%.

  16. Boron removal from geothermal waters by electrocoagulation

    International Nuclear Information System (INIS)

    Yilmaz, A. Erdem; Boncukcuoglu, Recep; Kocakerim, M. Muhtar; Yilmaz, M. Tolga; Paluluoglu, Cihan

    2008-01-01

    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. Removal of boron (B) from waste liquors.

    Science.gov (United States)

    Jiang, J Q; Xu, Y; Simon, J; Quill, K; Shettle, K

    2006-01-01

    This paper explores the use of electrocoagulation to remove boron from waste effluent in comparison with alum coagulation. In treating model test wastes, greater boron removals were achieved with electrocoagulation at low doses than conventional alum coagulation when reaction was undertaken for the same conditions (pH 8.5, and initial boron concentration was 500 mg/L). Al electrocoagulation can achieve good boron removal performance (68.3%) at a dose of 2.1 (as molar ratio of Al:B, and for current density of 62.1 A/m2), while alum coagulation can only achieve the maximum boron removal of 56% at a dose of 2.4. Also, Al electrocoagulation can remove 15-20% more boron than alum coagulation for the same dose compared in the treatment of both model test wastes and industry effluent. The estimation of running costs shows that to achieve 75% boron removal from industry waste effluent, i.e. removing 150 g of boron from 1 m3 of effluent, electrocoagulation was 6.2 times cheaper than alum coagulation. The economic advantage of electrocoagulation in the treatment of boron-containing waste effluent is thus significant.

  18. Preparation, Characterization and Adsorption Study of Granular Activated Carbon/Iron oxide composite for the Removal of Boron and Organics from Wastewater

    Directory of Open Access Journals (Sweden)

    Affam Augustine Chioma

    2018-01-01

    Full Text Available Boron and organics maybe in high concentration during production of oil and gas, fertilizers, glass, and detergents. In addition, boron added to these industrial processes may require to be removed by the wastewater treatment plant. The preparation, characterization and application of iron oxide-activated carbon composite for removal of boron and COD was studied. The one variable at a time (OVAT method was implemented to obtain desirable operating conditions (adsorbent dosage 5 g/L, reaction time 2 h, agitation speed 100 rpm, pH 5 for COD removal and pH 9 for boron removal. It was found that boron and organics present in a sample wastewater may require to be treated separately to remove the contaminants. The study achieved 97 and 70% for boron and COD removal, respectively. Adsorption as an alternative cheap source of treatment and its practicability for small communities is recommended as effective in removal of contaminants from river water.

  19. Preparation, Characterization and Adsorption Study of Granular Activated Carbon/Iron oxide composite for the Removal of Boron and Organics from Wastewater

    Science.gov (United States)

    Chioma Affam, Augustine; Chung Wong, Chee; Seyam, Mohammed A. B.; Matt, Chelsea Ann Anak Frederick; Lantan Anak Sumbai, Josephine; Evuti, Abdullahi Mohammed

    2018-03-01

    Boron and organics maybe in high concentration during production of oil and gas, fertilizers, glass, and detergents. In addition, boron added to these industrial processes may require to be removed by the wastewater treatment plant. The preparation, characterization and application of iron oxide-activated carbon composite for removal of boron and COD was studied. The one variable at a time (OVAT) method was implemented to obtain desirable operating conditions (adsorbent dosage 5 g/L, reaction time 2 h, agitation speed 100 rpm, pH 5 for COD removal and pH 9 for boron removal). It was found that boron and organics present in a sample wastewater may require to be treated separately to remove the contaminants. The study achieved 97 and 70% for boron and COD removal, respectively. Adsorption as an alternative cheap source of treatment and its practicability for small communities is recommended as effective in removal of contaminants from river water.

  20. Relative accuracy and availability of an Irish National Database of dispensed medication as a source of medication history information: observational study and retrospective record analysis.

    LENUS (Irish Health Repository)

    Grimes, T

    2013-01-27

    WHAT IS KNOWN AND OBJECTIVE: The medication reconciliation process begins by identifying which medicines a patient used before presentation to hospital. This is time-consuming, labour intensive and may involve interruption of clinicians. We sought to identify the availability and accuracy of data held in a national dispensing database, relative to other sources of medication history information. METHODS: For patients admitted to two acute hospitals in Ireland, a Gold Standard Pre-Admission Medication List (GSPAML) was identified and corroborated with the patient or carer. The GSPAML was compared for accuracy and availability to PAMLs from other sources, including the Health Service Executive Primary Care Reimbursement Scheme (HSE-PCRS) dispensing database. RESULTS: Some 1111 medication were assessed for 97 patients, who were median age 74 years (range 18-92 years), median four co-morbidities (range 1-9), used median 10 medications (range 3-25) and half (52%) were male. The HSE-PCRS PAML was the most accurate source compared to lists provided by the general practitioner, community pharmacist or cited in previous hospital documentation: the list agreed for 74% of the medications the patients actually used, representing complete agreement for all medications in 17% of patients. It was equally contemporaneous to other sources, but was less reliable for male than female patients, those using increasing numbers of medications and those using one or more item that was not reimbursable by the HSE. WHAT IS NEW AND CONCLUSION: The HSE-PCRS database is a relatively accurate, available and contemporaneous source of medication history information and could support acute hospital medication reconciliation.

  1. Polycyclic aromatic hydrocarbons (PAHs) in sediments from lake Lille Lungegårdsvannet in Bergen, western Norway; appraising pollution sources from the urban history.

    Science.gov (United States)

    Andersson, Malin; Klug, Martin; Eggen, Ola Anfin; Ottesen, Rolf Tore

    2014-02-01

    This study aims to determine the temporal character and concentration variability of polycyclic aromatic hydrocarbon (PAH) during the last 5,400 years in urban lake sediments through a combination of dating and chemo-stratigraphical correlation. We investigate the chemical history of the city of Bergen and determine the effect of specific point sources, as well as diffuse sources, and also help assess the risk of remediation plans. By using several organic compounds, metals and cyanide, we demonstrate the more accurate timing of sedimentation. The PAH results display very low concentrations in pre-industrial times, followed by a general increase that is punctuated by a few significant concentration increases. These most probably correspond to urban fires, domestic heating, gaswork activity and most recently due to traffic pollution. At the same depth as a significant rise in concentration from background levels occurred, the high relative occurrence of low-molecular-weight PAH-compounds, such as naphthalene, were replaced by heavier compounds, thus indicating a permanent change in source. The general observation, using ratios, is that the sources have shifted from pre-industrial pure wood and coal combustion towards mixed and petrogenic sources in more recent times. The (14)C dating provides evidence that the sedimentation rate stayed more-or-less constant for 4,500 years (from 7200 to 2700 calibrated years before present (calyr BP)), before isostatic uplift isolated the water body and the sedimentation rate decreased or sediments were eroded. The sediment input increased again when habitation and industrial activities encroached on the lake. The (14)C dating does not provide consistent data in that period, possibly due to the fact that the lake has been used as a waste site throughout the history of Bergen city. Therefore, results from (14)C dating from anthropogenically influenced sediments should be used with caution. © 2013.

  2. The armour of the common soldier in the late middle ages. Harnischrödel as sources for the history of urban martial culture

    OpenAIRE

    Schmid Regula

    2017-01-01

    The designation Harnischrödel (rolls of armour) lumps together different kinds of urban inventories. They list the names of citizens and inhabitants together with the armour they owned, were compelled to acquire within their civic obligations, or were obliged to lend to able-bodied men. This contribution systematically introduces Harnischrödel of the 14th and 15th c. as important sources for the history of urban martial culture. On the basis of lists preserved in the archives of Swiss towns, ...

  3. The armour of the common soldier in the late middle ages. "Harnischrödel" as sources for the history of urban martial culture

    OpenAIRE

    Schmid, Regula

    2017-01-01

    The designation Harnischrödel (rolls of armour) lumps together different kinds of urban inventories. They list the names of citizens and inhabitants together with the armour they owned, were compelled to acquire within their civic obligations, or were obliged to lend to able-bodied men. This contribution systematically introduces Harnischrödel of the 14th and 15th c. as important sources for the history of urban martial culture. On the basis of lists preserved in the archives of Swiss towns, ...

  4. Pressure effects on dynamics behavior of multiwall boron nitride nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Talebian, Taha [Faculty of Engineering, Neyshabur Branch, Islamic Azad University, Neyshabur (Iran, Islamic Republic of)

    2016-01-15

    The dynamic behavior of Multiwall boron nitride nanotubes (MWBNNTs) is investigated by employing multiple elastic shells model. The influences of van der Waals interactions on layers are shown as nonlinear functions of the interlayer distance of MWBNNTs. Governing equations are solved by using the developed finite element method and by employing time history diagrams. The radial wave speed from the outermost layer to the innermost layer is computed. The effects of geometrical factors such as diameter-to-thickness ratio on dynamic behavior of MWBNNTs are determined. The magnification aspects of MWBNNTs are computed, and the effects of surrounding pressures on wave speed and magnification aspect of MWBNNTs are discussed.

  5. Genome Size, Molecular Phylogeny, and Evolutionary History of the Tribe Aquilarieae (Thymelaeaceae, the Natural Source of Agarwood

    Directory of Open Access Journals (Sweden)

    Azman H. Farah

    2018-05-01

    Full Text Available The tribe Aquilarieae of the family Thymelaeaceae consists of two genera, Aquilaria and Gyrinops, with a total of 30 species, distributed from northeast India, through southeast Asia and the south of China, to Papua New Guinea. They are an important botanical resource for fragrant agarwood, a prized product derived from injured or infected stems of these species. The aim of this study was to estimate the genome size of selected Aquilaria species and comprehend the evolutionary history of Aquilarieae speciation through molecular phylogeny. Five non-coding chloroplast DNA regions and a nuclear region were sequenced from 12 Aquilaria and three Gyrinops species. Phylogenetic trees constructed using combined chloroplast DNA sequences revealed relationships of the studied 15 members in Aquilarieae, while nuclear ribosomal DNA internal transcribed spacer (ITS sequences showed a paraphyletic relationship between Aquilaria species from Indochina and Malesian. We exposed, for the first time, the estimated divergence time for Aquilarieae speciation, which was speculated to happen during the Miocene Epoch. The ancestral split and biogeographic pattern of studied species were discussed. Results showed no large variation in the 2C-values for the five Aquilaria species (1.35–2.23 pg. Further investigation into the genome size may provide additional information regarding ancestral traits and its evolution history.

  6. Evaluation of radioactivity in the bodies of mice induced by neutron exposure from an epi-thermal neutron source of an accelerator-based boron neutron capture therapy system

    Science.gov (United States)

    NAKAMURA, Satoshi; IMAMICHI, Shoji; MASUMOTO, Kazuyoshi; ITO, Masashi; WAKITA, Akihisa; OKAMOTO, Hiroyuki; NISHIOKA, Shie; IIJIMA, Kotaro; KOBAYASHI, Kazuma; ABE, Yoshihisa; IGAKI, Hiroshi; KURITA, Kazuyoshi; NISHIO, Teiji; MASUTANI, Mitsuko; ITAMI, Jun

    2017-01-01

    This study aimed to evaluate the residual radioactivity in mice induced by neutron irradiation with an accelerator-based boron neutron capture therapy (BNCT) system using a solid Li target. The radionuclides and their activities were evaluated using a high-purity germanium (HP-Ge) detector. The saturated radioactivity of the irradiated mouse was estimated to assess the radiation protection needs for using the accelerator-based BNCT system. 24Na, 38Cl, 80mBr, 82Br, 56Mn, and 42K were identified, and their saturated radioactivities were (1.4 ± 0.1) × 102, (2.2 ± 0.1) × 101, (3.4 ± 0.4) × 102, 2.8 ± 0.1, 8.0 ± 0.1, and (3.8 ± 0.1) × 101 Bq/g/mA, respectively. The 24Na activation rate at a given neutron fluence was found to be consistent with the value reported from nuclear-reactor-based BNCT experiments. The induced activity of each nuclide can be estimated by entering the saturated activity of each nuclide, sample mass, irradiation time, and proton current into the derived activation equation in our accelerator-based BNCT system. PMID:29225308

  7. Investigation of Properties of Asphalt Concrete Containing Boron Waste as Mineral Filler

    Directory of Open Access Journals (Sweden)

    Cahit GÜRER

    2016-05-01

    Full Text Available During the manufacture of compounds in the boron mining industry a large quantity of waste boron is produced which has detrimental effects on the environment. Large areas have to be allocated for the disposal of this waste. Today with an increase in infrastructure construction, more efficient use of the existing sources of raw materials has become an obligation and this involves the recycling of various waste materials. Road construction requires a significant amount of raw materials and it is possible that substantial amounts of boron-containing waste materials can be recycled in these applications. This study investigates the usability of boron wastes as filler in asphalt concrete. For this purpose, asphalt concrete samples were produced using mineral fillers containing 4%, 5%, 6%, 7% and 8% boron waste as well as a 6% limestone filler (6%L as the control sample. The Marshall Design, mechanical immersion and Marshall Stability test after a freeze-thaw cycle and indirect tensile stiffness modulus (ITSM test were performed for each of the series. The results of this experimental study showed that boron waste can be used in medium and low trafficked asphalt concrete pavements wearing courses as filler.

  8. Radio response of human lymphocytes pretreated with boron and gadoliniums assessed by the, comet assay

    International Nuclear Information System (INIS)

    Kim, J. K.; Park, T. W.; Cebulska-Wasiewska, A.; Nili, M.

    2009-01-01

    Boron and gadolinium are among the nuclides that hold a unique property of being a neutron capture therapy agent. Neutron beams have often a considerable portion of gamma rays with fast neutrons. Gamma rays, as beam contaminants, can cause considerable damage to normal tissues even if such tissues do contain high boron concentrations. Materials and Methods: The modification of radio response in human lymphocytes pretreated with boron or gadolinium compound was studied by assessing the DNA damage using single cell gel electrophoresis, the comet assay. The lymphocytes from the human peripheral blood were irradiated with 0, 1, 2 and 4 Gy of gamma rays from a 60 Co isotopic source with or without pretreatment of boron or gadolinium compound for 10 minutes at 4 d egree C . Post-irradiation procedures included slide preparation, cell-lysing, unwinding and electrophoresis, neutralization, staining, and analytic steps, gel electrophoresis. Results: The results indicate that pretreatment with boron compound (50 n M or 250 n M of 10 B) is effective in reducing the radiosensitivity of the lymphocyte DNA. Conversely, pretreatment with gadolinium compound (50 n M) led to a dose-dependent increase in the radiosensitivity, most prominently with a dose of 4 Gy (P<0.001). Furthermore, when the lymphocytes were pretreated with a Combined mixture (1:1) of boron (250 n M) and gadolinium (50 n M) compounds, the reduced radiosensitivity was also observed.

  9. Thermodynamic approach to the conditions of chemical deposition of boron by contact with an inert substrate

    International Nuclear Information System (INIS)

    Thebault, J.; Naslain, R.; Hagenmuller, P.; Bernard, C.

    1978-01-01

    The optimum conditions for the synthesis of boron by chemical vapour deposition (CVD) from BCl 3 -H 2 or BBr 3 -H 2 mixtures onto an inert substrate (boron or boronized metals) have been studied by a thermodynamic approach. This approach, which postulates that states close to equilibrium are reached in the vicinity of the hot substrate, is based on the minimization of the total Gibbs free energy of the system. Between 1200 and 1900 K and under a total pressure of 1 atm, the hydrogen reduction of BCl 3 can lead to two types of by-products: BHCl 2 at all temperatures, and BCl 2 or BCl subhalides at high temperatures; BHCl 2 is the main product of the reduction at the lowest temperatures. The hydrogen reduction of BCl 3 is never complete for the conditions commonly used for the synthesis of boron. The amount of by-products and of BBr 3 which must be recycled can be minimized by utilizing BCl 3 -H 2 mixtures rich in hydrogen. The amount of boron deposited exhibits a maximum for a temperature close to 1700 K. Similar results have been obtained for BBr 3 . However, between 1000 and 1500 K and under a total pressure of 1 atm the amount of by-products (BHBr 2 and BBr 2 ) is smaller than in the case of BCl 3 . The boron yield from the reduction of BBr 3 is higher than that from BCl 3 and the percentage of boron halide which must be recycled is lower in the case of BBr 3 . Thus, BBr 3 appears to be a better source than BCl 3 for the CVD of boron. (Auth.)

  10. A technique to prepare boronated B72.3 monoclonal antibody for boron neutron capture therapy

    International Nuclear Information System (INIS)

    Ranadive, G.N.; Rosenzweig, H.S.; Epperly, M.W.

    1993-01-01

    B72.3 monoclonal antibody has been successfully boronated using mercaptoundecahydro-closo-dodecaborate (boron cage compound). The reagent was incorporated by first reacting the lysine residues of the antibody with m-maleimidobenzoyl succinimide ester (MBS), followed by Michael addition to the maleimido group by the mercapto boron cage compound to form a physiologically stable thioether linkage. Boron content of the antibody was determined by atomic absorption spectroscopy. For biodistribution studies, boronated antibody was radioiodinated with iodogen. 125 I-labeled and boronated B72.3 monoclonal antibody demonstrated clear tumor localization when administered via tail vein injections to athymic nude mice bearing LS174-T tumor xenografts. Boronated antibody was calculated to deliver 10 6 boron atoms per tumor cell. Although this falls short of the specific boron content originally proposed as necessary for boron neutron capture therapy (BNCT), recent calculations suggest that far fewer atoms of 10 B per tumor cell would be necessary to effect successful BNCT when the boron is targeted to the tumor cell membrane. (author)

  11. The armour of the common soldier in the late middle ages. Harnischrödel as sources for the history of urban martial culture

    Directory of Open Access Journals (Sweden)

    Schmid Regula

    2017-12-01

    Full Text Available The designation Harnischrödel (rolls of armour lumps together different kinds of urban inventories. They list the names of citizens and inhabitants together with the armour they owned, were compelled to acquire within their civic obligations, or were obliged to lend to able-bodied men. This contribution systematically introduces Harnischrödel of the 14th and 15th c. as important sources for the history of urban martial culture. On the basis of lists preserved in the archives of Swiss towns, it concentrates on information pertaining to the type and quality of an average urban soldier’s gear. Although the results of this analysis are only preliminary – at this point, it is not possible to produce methodologically sound statistics –, the value of the lists as sources is readily evident, as only a smattering of the once massive quantity of actual objects has survived down to the present time.

  12. Boron carbide synthesis by carbothermic reduction of boron oxide

    International Nuclear Information System (INIS)

    Castro, A.R.M. de; Paschoal, J.O.A.

    1988-01-01

    Boron carbide (B 4 C) is a ceramic material of technological applications due to its extreme hardness and high chemical as well as thermal stability. Some parameters of the process for obtaining B 4 C by carbothermic reduction of B 2 O 3 have been determined. The starting powders and the final products have been analysed by chemical, spectrographic and X-ray diffraction methods. The results show that the B 4 C obtained by the carbothermic reduction process is suitable for applications with a definite determination of the free carbon content. (author) [pt

  13. Sources for researching the business history of Spanish mining; Fuentes para la historia empresarial de la mineria espanola

    Energy Technology Data Exchange (ETDEWEB)

    Perez de Perceval Verde, M. A.; Lopez-Morell, M. A.

    2013-09-01

    This article analyzes the sources available when studying the firms that have exploited underground resources in Spain in contemporary times. The materials we have are diverse, given the variety of mining areas, minerals, types of firms, nationalities involved, etc. Large businesses are covered, in the main, by business archives, which have evolved in different ways, whilst for smaller concerns and when reconstructing an overall business and production map the researcher is better served by tax registers, in particular those on the gross production tax. A wide set of sources with details of where to find them, what they offer, the obstacles they can produce and how best to use them to study the mining business fabric is also included. (Author)

  14. High strain amount in recessed junctions induced by selectively deposited boron-doped SiGe layers

    Energy Technology Data Exchange (ETDEWEB)

    Radamson, H.H. [School of Information and Communication Technology, KTH (Royal Institute of Technology) Isafjordsg. 22-26, Electrum 229, 16640 Kista (Sweden)], E-mail: rad@kth.se; Kolahdouz, M.; Ghandi, R.; Ostling, M. [School of Information and Communication Technology, KTH (Royal Institute of Technology) Isafjordsg. 22-26, Electrum 229, 16640 Kista (Sweden)

    2008-12-05

    This work presents the selective epitaxial growth (SEG) of Si{sub 1-x}Ge{sub x} (x = 0.15-0.315) layers with high amount of boron (1 x 10{sup 20}-1 x 10{sup 21} cm{sup -3}) in recessed or unprocessed (elevated) openings for source/drain applications in CMOS has been studied. The influence of the growth rate and strain on boron incorporation has been studied. A focus has been made on the strain distribution and boron incorporation in SEG of SiGe layers.

  15. High strain amount in recessed junctions induced by selectively deposited boron-doped SiGe layers

    International Nuclear Information System (INIS)

    Radamson, H.H.; Kolahdouz, M.; Ghandi, R.; Ostling, M.

    2008-01-01

    This work presents the selective epitaxial growth (SEG) of Si 1-x Ge x (x = 0.15-0.315) layers with high amount of boron (1 x 10 20 -1 x 10 21 cm -3 ) in recessed or unprocessed (elevated) openings for source/drain applications in CMOS has been studied. The influence of the growth rate and strain on boron incorporation has been studied. A focus has been made on the strain distribution and boron incorporation in SEG of SiGe layers

  16. Synthesis and Suzuki Cross-Coupling Reactions of 2,6-Bis(trifluoromethyl)pyridine-4-boronic Acid Pinacol Ester

    KAUST Repository

    Batool, Farhat

    2016-11-18

    Iridium-catalyzed aromatic borylation provides quick one-step access to 2,6-bis(trifluoromethyl)pyridine-4-boronic acid pinacol ester. Suzuki couplings of this highly electron-deficient pyridine-4-boronic ester with various (hetero)aryl bromides was successfully carried out and the coupled products were obtained in 46–95% isolated yields. Double and triple Suzuki couplings, with dibromo- and tribromoarenes, respectively, were also achieved. Thus demonstrating that this pyridine-4-boronic ester can be a useful source for the installation of one of the strongest electron-withdrawing aromatic group in organic compounds. Copyright © 2016, Georg Thieme Verlag. All rights reserved.

  17. Synthesis and Suzuki Cross-Coupling Reactions of 2,6-Bis(trifluoromethyl)pyridine-4-boronic Acid Pinacol Ester

    KAUST Repository

    Batool, Farhat; Emwas, Abdul-Hamid M.; Gao, Xin; Munawar, Munawar A.; Chotana, Ghayoor A.

    2016-01-01

    Iridium-catalyzed aromatic borylation provides quick one-step access to 2,6-bis(trifluoromethyl)pyridine-4-boronic acid pinacol ester. Suzuki couplings of this highly electron-deficient pyridine-4-boronic ester with various (hetero)aryl bromides was successfully carried out and the coupled products were obtained in 46–95% isolated yields. Double and triple Suzuki couplings, with dibromo- and tribromoarenes, respectively, were also achieved. Thus demonstrating that this pyridine-4-boronic ester can be a useful source for the installation of one of the strongest electron-withdrawing aromatic group in organic compounds. Copyright © 2016, Georg Thieme Verlag. All rights reserved.

  18. Fabrication of boron-phosphide neutron detectors

    International Nuclear Information System (INIS)

    Fitzsimmons, M.; Pynn, R.

    1997-01-01

    Boron phosphide is a potentially viable candidate for high neutron flux neutron detectors. The authors have explored chemical vapor deposition methods to produce such detectors and have not been able to produce good boron phosphide coatings on silicon carbide substrates. However, semi-conducting quality films have been produced. Further testing is required

  19. Boron rates for triticale and wheat crops

    Directory of Open Access Journals (Sweden)

    Corrêa Juliano Corulli

    2005-01-01

    Full Text Available No reports are registered on responses to boron fertilization nutrient deficiency and toxicity in triticale crops. The aim of this study was to evaluate triticale response to different rates of boron in comparison to wheat in an hapludox with initial boron level at 0.08 mg dm-3 4 4 factorial design trial completely randomized blocks design (n = 4. Boron rates were 0; 0.62; 1.24 and 1.86 mg dm-3; triticale cultivars were IAC 3, BR 4 and BR 53 and IAPAR 38 wheat crop was used for comparison. The wheat (IAPAR 38 crop presented the highest boron absorption level of all. Among triticale cultivars, the most responsive was IAC 53, presenting similar characteristics to wheat, followed by BR 4; these two crops are considered tolerant to higher boron rates in soil. Regarding to BR 53, no absorption effect was observed, and the cultivars was sensitive to boron toxicity. Absorption responses differed for each genotype. That makes it possible to choose and use the best-adapted plants to soils with different boron rates.

  20. Hot flow behavior of boron microalloyed steels

    International Nuclear Information System (INIS)

    Lopez-Chipres, E.; Mejia, I.; Maldonado, C.; Bedolla-Jacuinde, A.; El-Wahabi, M.; Cabrera, J.M.

    2008-01-01

    This research work studies the effect of boron contents on the hot flow behavior of boron microalloyed steels. For this purpose, uniaxial hot-compression tests were carried out in a low carbon steel microalloyed with four different amounts of boron over a wide range of temperatures (950, 1000, 1050 and 1100 deg. C) and constant true strain rates (10 -3 , 10 -2 and 10 -1 s -1 ). Experimental results revealed that both peak stress and peak strain tend to decrease as boron content increases, which indicates that boron additions have a solid solution softening effect. Likewise, the flow curves show a delaying effect on the kinetics of dynamic recrystallization (DRX) when increasing boron content. Deformed microstructures show a finer austenitic grain size in the steel with higher boron content (grain refinement effect). Results are discussed in terms of boron segregation towards austenitic grain boundaries during plastic deformation, which increases the movement of dislocations, enhances the grain boundary cohesion and modificates the grain boundary structure

  1. Elastic modulus and fracture of boron carbide

    International Nuclear Information System (INIS)

    Hollenberg, G.W.; Walther, G.

    1978-12-01

    The elastic modulus of hot-pressed boron carbide with 1 to 15% porosity was measured at room temperature. K/sub IC/ values were determined for the same porosity range at 500 0 C by the double torsion technique. The critical stress intensity factor of boron carbide with 8% porosity was evaluated from 25 to 1200 0 C

  2. Polycyclic aromatic hydrocarbons (PAHs) in a large South American industrial coastal area (Santos Estuary, Southeastern Brazil): Sources and depositional history

    International Nuclear Information System (INIS)

    Martins, Cesar C.; Bicego, Marcia C.; Mahiques, Michel M.; Figueira, Rubens C.L.; Tessler, Moyses G.; Montone, Rosalinda C.

    2011-01-01

    Highlights: → In early 1980s, Santos Estuary became known as one of the worst polluted in the world. → PAHs levels were similar to the values reported for marine sediments worldwide. → PAHs analyses indicated multiple sources of these compounds (oil and pyrolitic origin). → The decline of oil consumption due to the world oil crisis (late 1970s) was shown. → The input of organic pollutants is a historical problem for the Santos Estuary. - Abstract: Located in southeastern Brazil, the Santos Estuary has the most important industrial and urban population area of South America. Since the 1950's, increased urbanization and industrialization near the estuary margins has caused the degradation of mangroves and has increased the discharge of sewage and industrial effluents. The main objectives of this work were to determine the concentrations and sources of polycyclic aromatic hydrocarbons (PAHs) in sediment cores in order to investigate the input of these substances in the last 50 years. The PAHs analyses indicated multiple sources of these compounds (oil and pyrolitic origin), basically anthropogenic contributions from biomass, coal and fossil fuels combustion. The distribution of PAHs in the cores was associated with the formation and development of Cubatao industrial complex and the Santos harbour, waste disposal, world oil crisis and the pollution control program, which results in the decrease of organic pollutants input in this area.

  3. Boron isotopic enrichment by displacement chromatography

    International Nuclear Information System (INIS)

    Mohapatra, K.K.; Bose, Arun

    2014-01-01

    10 B enriched boron is used in applications requiring high volumetric neutron absorption (absorption cross section- 3837 barn for thermal and 1 barn for 1 MeV fast neutron). It is used in fast breeder reactor (as control rod material), in neutron counter, in Boron Neutron Capture Therapy etc. Owing to very small separation factor, boron isotopic enrichment is a complex process requiring large number of separation stages. Heavy Water Board has ventured in industrial scale production of 10 B enriched boron using Exchange Distillation Process as well as Ion Displacement Chromatography Process. Ion Displacement Chromatography process is used in Boron Enrichment Plant at HWP, Manuguru. It is based on isotopic exchange between borate ions (B(OH) 4 - ) on anion exchange resin and boric acid passing through resin. The isotopic exchange takes place due to difference in zero point energy of 10 B and 11 B

  4. XPS analysis of boron doped heterofullerenes

    Energy Technology Data Exchange (ETDEWEB)

    Schnyder, B; Koetz, R [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Muhr, H J; Nesper, R [ETH Zurich, Zurich (Switzerland)

    1997-06-01

    Boron heterofullerenes were generated through arc-evaporation of doped graphite rods in a helium atmosphere. According to mass spectrometric analysis only mono-substituted fullerenes like C{sub 59}B, C{sub 69}B and higher homologues together with a large fraction of higher undoped fullerenes were extracted and enriched when pyridine was used as the solvent. XPS analysis of the extracts indicated the presence of two boron species with significantly different binding energies. One peak was assigned to borid acid. The second one corresponds to boron in the fullerene cage, which is mainly C{sub 59}B, according to the mass spectrum. This boron is in a somewhat higher oxidation state than that of ordinary boron-carbon compounds. The reported synthesis and extraction procedure opens a viable route for production of macroscopic amounts of these compounds. (author) 2 figs., 1 tab., 7 refs.

  5. Cathodoluminescence of cubic boron nitride

    International Nuclear Information System (INIS)

    Tkachev, V.D.; Shipilo, V.B.; Zajtsev, A.M.

    1985-01-01

    Three optically active defects are detected in mono- and polycrystal cubic boron nitride (β-BN). Analysis of intensity of temperature dependences, halfwidth and energy shift of 1.76 eV narrow phononless line (center GC-1) makes it possible to interprete the observed cathodoluminescence spectra an optical analog of the Moessbaner effect. Comparison of the obtained results with the known data for diamond monocrystals makes it possible to suggest that the detected center GC-1 is a nitrogen vacancy . The conclusion, concerning the Moessbauer optical spectra application, is made to analyze structural perfection of β-BN crystal lattice

  6. Extreme-UV electrical discharge source

    Science.gov (United States)

    Fornaciari, Neal R.; Nygren, Richard E.; Ulrickson, Michael A.

    2002-01-01

    An extreme ultraviolet and soft x-ray radiation electric capillary discharge source that includes a boron nitride housing defining a capillary bore that is positioned between two electrodes one of which is connected to a source of electric potential can generate a high EUV and soft x-ray radiation flux from the capillary bore outlet with minimal debris. The electrode that is positioned adjacent the capillary bore outlet is typically grounded. Pyrolytic boron nitride, highly oriented pyrolytic boron nitride, and cubic boron nitride are particularly suited. The boron nitride capillary bore can be configured as an insert that is encased in an exterior housing that is constructed of a thermally conductive material. Positioning the ground electrode sufficiently close to the capillary bore outlet also reduces bore erosion.

  7. Chemistry and technology of boron and its compounds

    International Nuclear Information System (INIS)

    Zhigach, A.F.; Parfenov, B.P.; Svitsyn, R.A.

    1995-01-01

    The results of research dealing with development of technologies of boron trichloride, boron hydride, aminoderivative boron hydrides, metal borohydrides, carboranes, carborane-containing polymers, carried out at the institute of organoelemental compounds, are presented. Physicochemical properties of the compounds have been studied and analytical methods have been developed. Data on toxicity and fire hazard of boron compounds are provided

  8. Analysis of boron nitride by flame spectrometry methods

    International Nuclear Information System (INIS)

    Telegin, G.F.; Chapysheva, G.Ya.; Shilkina, N.N.

    1989-01-01

    A rapid method has been developed for determination of free and total boron contents as well as trace impurities in boron nitride by using autoclave sample decomposition followed by atomic emission and atomic absorption determination. The relative standard deviation is not greater than 0.03 in the determination of free boron 0.012 in the determination of total boron content

  9. Rare-earth doped boron nitride nanotubes: Synthesis and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Wellington Marcos; Sousa, Edesia Martins Barros de, E-mail: wellingtonmarcos@yahoo.com.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2016-07-01

    Full text: Boron nitride is a heat and chemically resistant refractory compound of boron and nitrogen atoms with the chemical formula BN. This structure exists in various crystalline forms that are isoelectronic to a similarly structured carbon lattice. The hexagonal form (h-BN) corresponding to graphite is the most stable and soft among BN polymorph. However, boron nitride nanotubes (BNNTs) were first time synthesized in 1995 [1] and have a type of one-dimensional (1D) nanostructure. Recently the BNNTs have attracted significant interest for scientific and technological applications due to their Wide bandgap. The Wide-bandgap semiconductors doped with rare-earth are considered as a new type of luminescent material, combining special Wide bandgap semiconducting properties with the rare-earth luminescence feature. BNNTs have a stable wide bandgap of 5.5 eV and super thermal and chemical stabilities, which make BNNTs an ideal nanosized luminescent material [2]. In this study, we report a simple and efficient route for the synthesis of BNNTs doped with samarium and europium. High quality BNNTs doped was produced via CVD technique using NH{sub 3} and N{sub 2} gases as source. Boron amorphous, catalyst and oxides rare-earth powder were used as precursor. Detailed studies involving energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and transmission electron microscope (TEM) were performed in order to characterize the BNNTs as grown. [1] Chopra, N. G.; Luyken, R. J. et al. Science, v. 269, p. 966-967, 1995. [2] Chen, H.; Chen, Y. et al. Adv. Matter. v. 19, p. 1845-1848, 2007. (author)

  10. Rare-earth doped boron nitride nanotubes: Synthesis and characterization

    International Nuclear Information System (INIS)

    Silva, Wellington Marcos; Sousa, Edesia Martins Barros de

    2016-01-01

    Full text: Boron nitride is a heat and chemically resistant refractory compound of boron and nitrogen atoms with the chemical formula BN. This structure exists in various crystalline forms that are isoelectronic to a similarly structured carbon lattice. The hexagonal form (h-BN) corresponding to graphite is the most stable and soft among BN polymorph. However, boron nitride nanotubes (BNNTs) were first time synthesized in 1995 [1] and have a type of one-dimensional (1D) nanostructure. Recently the BNNTs have attracted significant interest for scientific and technological applications due to their Wide bandgap. The Wide-bandgap semiconductors doped with rare-earth are considered as a new type of luminescent material, combining special Wide bandgap semiconducting properties with the rare-earth luminescence feature. BNNTs have a stable wide bandgap of 5.5 eV and super thermal and chemical stabilities, which make BNNTs an ideal nanosized luminescent material [2]. In this study, we report a simple and efficient route for the synthesis of BNNTs doped with samarium and europium. High quality BNNTs doped was produced via CVD technique using NH 3 and N 2 gases as source. Boron amorphous, catalyst and oxides rare-earth powder were used as precursor. Detailed studies involving energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and transmission electron microscope (TEM) were performed in order to characterize the BNNTs as grown. [1] Chopra, N. G.; Luyken, R. J. et al. Science, v. 269, p. 966-967, 1995. [2] Chen, H.; Chen, Y. et al. Adv. Matter. v. 19, p. 1845-1848, 2007. (author)

  11. Ion sources for medical accelerators

    Science.gov (United States)

    Barletta, W. A.; Chu, W. T.; Leung, K. N.

    1998-02-01

    Advanced injector systems for proton synchrotrons and accelerator-based boron neutron capture therapy systems are being developed at the Lawrence Berkeley National Laboratory. Multicusp ion sources, particularly those driven by radio frequency, have been tested for these applications. The use of a radio frequency induction discharge provides clean, reliable, and long-life source operation. It has been demonstrated that the multicusp ion source can provide good-quality positive hydrogen ion beams with a monatomic ion fraction higher than 90%. The extractable ion current densities from this type of source can meet the injector requirements for both proton synchrotron and accelerator-based boron neutron capture therapy projects.

  12. Reduction in Recombination Current Density in Boron Doped Silicon Using Atomic Hydrogen

    Science.gov (United States)

    Young, Matthew Garett

    The solar industry has grown immensely in recent years and has reached a point where solar energy has now become inexpensive enough that it is starting to emerge as a mainstream electrical generation source. However, recent economic analysis has suggested that for solar to become a truly wide spread source of electricity, the costs still need to plummet by a factor of 8x. This demands new and innovative concepts to help lower such cost. In pursuit of this goal, this dissertation examines the use of atomic hydrogen to lessen the recombination current density in the boron doped region of n-type silicon solar cells. This required the development of a boron diffusion process that maintained the bulk lifetime of n-type silicon such that the recombination current density could be extracted by photoconductance spectroscopy. It is demonstrated that by hydrogenating boron diffusions, the majority carrier concentration can be controlled. By using symmetrically diffused test structures with quinhydrone-methanol surface passivation the recombination current density of a hydrogenated boron profile is shown to be less than that of a standard boron profile, by as much as 30%. This is then applied to a modified industrial silicon solar cell process to demonstrate an efficiency enhancement of 0.4%.

  13. Organic maturation levels, thermal history and hydrocarbon source rock potential of the Namurian rocks of the Clare Basin, Ireland

    Energy Technology Data Exchange (ETDEWEB)

    Goodhue, Robbie; Clayton, Geoffrey [Trinity Coll., Dept. of Geology, Dublin (Ireland)

    1999-11-01

    Vitrinite reflectance data from two inland cored boreholes confirm high maturation levels throughout the onshore part of the Irish Clare Basin and suggest erosion of 2 to 4 km of late Carboniferous cover and elevated palaeogeothermal gradients in the Carboniferous section. The observed maturation gradients are fully consistent with the published hypothesis of a late Carboniferous/Permian 'superplume' beneath Pangaea but local vertical reversals in gradients also suggest a complex thermal regime probably involving advective heating. The uppermost Visean--lower Namurian Clare Shale is laterally extensive and up to 300 m thick. Although this unit is post-mature, TOC values of up to 15% suggest that it could have considerable hydrocarbon source rock potential in any less mature offshore parts of the basin. (Author)

  14. Study of ceramic mixed boron element as a neutron shielding

    International Nuclear Information System (INIS)

    Ismail Mustapha; Mohd Reusmaazran Yusof; Md Fakarudin Ab Rahman; Nor Paiza Mohamad Hasan; Samihah Mustaffha; Yusof Abdullah; Mohamad Rabaie Shari; Airwan Affandi Mahmood; Nurliyana Abdullah; Hearie Hassan

    2012-01-01

    Shielding upon radiation should not be underestimated as it can causes hazard to health. Precautions on the released of radioactive materials should be well concerned and considered. Therefore, the combination of ceramic and boron make them very useful for shielding purpose in areas of low and intermediate neutron. A six grades of ceramic tile have been produced namely IMN05 - 5 % boron, IMN06 - 6 % boron, IMN07 - 7 % boron, IMN08 - 8 % boron, IMN09 - 9 % boron, IMN10 - 10 % boron from mixing, press and sintered process. Boron is a material that capable of absorbing and capturing neutron, so that neutron and gamma test were conducted to analyze the effectiveness of boron material in combination with ceramic as shielding. From the finding, percent reduction number of count per minute shows the ceramic tiles are capable to capture neutron. Apart from all the percentage of boron used, 10 % is the most effective shields since the percent reduction indicating greater neutron captured increased. (author)

  15. Comparison of the Level of Boron Concentrations in Black Teas with Fruit Teas Available on the Polish Market

    Directory of Open Access Journals (Sweden)

    Anetta Zioła-Frankowska

    2014-01-01

    Full Text Available The determination of boron by inductively coupled plasma-atomic emission spectrometry has been carried in water-soluble and acid soluble (total content fractions of 36 samples of traditional black tea and fruit brew. The estimation of the impact of the type of tea on the concentration of boron in water-soluble and acid extracts and potential human health risk from the daily intake of boron was carried out in this study. The levels of boron differed significantly in black and fruit tea types. The mean total content of boron ranged from 8.31 to 18.40 mg/kg in black teas, from 12.85 to 15.13 mg/kg in black tea with fruit flavor, and from 12.09 to 22.77 mg/kg in fruit brews. The degree of extraction of boron in black tea ranged from 8% to 27% and for fruit tea from 17% to 69%. In addition, the values below 25% were of black teas with fruit flavors. The daily intake of B from tea infusions (three cups/day is still within the average daily intake except for some of the fruit brews which exceed acceptable regulations of the daily intake of total boron by humans. Hence, it may not produce any health risks for human consumption, if other sources of metal contaminated food are not taken at the same time.

  16. Boron-Loaded Silicone Rubber Scintillators

    Energy Technology Data Exchange (ETDEWEB)

    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.

  17. Cell cycle dependence of boron uptake in various boron compounds used for neutron capture therapy

    International Nuclear Information System (INIS)

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

    2000-01-01

    In neutron capture therapy, it is important that the tumor take boron in selectively. Furthermore, it is ideal when the uptake is equal in each tumor cell. Some indirect proof of differences in boron uptake among neoplastic cell cycles has been documented. However, no investigation has yet measured boron uptake directly. Using flow cytometry, in the present study cells were sorted by G0/G1 phase and G2/M phase, and the boron concentration of each fraction was measured with inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The results were that BSH (sodiumborocaptate) and BPA (p-boronophenylalanine) had higher rates of boron uptake in the G2/M group than in the G0/G1 group. However, in BPA the difference was more prominent, which revealed a 2.2-3.3 times higher uptake of boron in the G2/M group than in the G0/G1 group. (author)

  18. The determination of boron and carbon in reactor grade boron carbide

    International Nuclear Information System (INIS)

    Crossley, D.; Wood, A.J.; McInnes, C.A.J.; Jones, I.G.

    1978-09-01

    The sealed tube method of dissolution at high temperature and pressure has been successfully applied in the analysis of reactor grade boron carbide for the determination of boron. A 50 mg sample of boron carbide is completely dissolved by heating with concentrated nitric acid in a sealed tube at 300 0 C. The boron content of the resultant sample solution is determined by the mannitol potentiometric titration method. The precision of the method for the determination of 2.5 mg of boron using the Harwell automatic potentiometric titrator is 0.2% (coefficient of variation). The carbon content of a boron carbide sample is determined by combustion of the sample at 1050 0 C in a stream of oxygen using vanadium pentoxide to ensure the complete oxidation of the sample. The carbon dioxide produced from the sample is measured manometrically and the precision of the method for the determination of 4 mg of carbon is 0.4% (coefficient of variation). (author)

  19. Improved tribological behavior of boron implanted Ti-6Al-4V

    International Nuclear Information System (INIS)

    Baker, N.P.; Walter, K.C.; Nastasi, M.

    1998-03-01

    Boron implanted of Ti6Al4V has been conducted at combinations of 32 and 40 keV to supplement that done previously at 75 keV. Shallower boron depth profiles with higher B-concentrations in the Ti64 surface have been obtained by tailoring the combinations of ion energy and dose. This work used three different ion energy and dose combinations of 4 x 10 17 B-at/cm 2 at 40 keV plus 2 x 10 17 B-at/cm 2 at 32 keV, 4 x 10 17 B-at/cm 2 at 40 keV, and 4 x 10 17 B-at/cm 2 at 32 keV plus 2 x 10 17 B-at/cm 2 at 40 keV. Comparisons are made between Ti6Al4V with a shallow implanted boron depth profile, Ti6Al4V with a deeper boron depth profile and nitrogen implanted using a plasma source ion implantation process. It has been previously shown that while boron implanted Ti64 has a ∼ 30% higher surface hardness than nitrogen implanted Ti64, the N-implantation reduced the wear coefficient of Ti64 by 25--120x, while B-implantation reduced the wear coefficient by 6.5x or less. The results show that no significant improvement is made in the wear resistance of boron implanted Ti6Al4V by increasing the concentration of boron at the surface from approximately 10% to 43%. Transmission electron microscopy (TEM) and selected area diffraction (SAD) indicated the formation of crystalline TiB in the implanted surface layer. Shallower depth profiles result in reductions of the Ti6Al4V wear coefficient by 6.5x or less which is the same result obtained earlier with the deeper boron depth profile. Surface hardness of Ti6Al4V with shallower boron depth profiles was improved approximately 10% compared to the results previously acquired with deeper boron depth profiles

  20. Geochemical and isotopic evidences for a severe anthropogenic boron contamination: A case study from Castelluccio (Arezzo, central Italy)

    International Nuclear Information System (INIS)

    Venturi, Stefania; Vaselli, Orlando; Tassi, Franco; Nisi, Barbara; Pennisi, Maddalena; Cabassi, Jacopo; Bicocchi, Gabriele; Rossato, Luca

    2015-01-01

    In 2009 a deterioration of garden plants watered with domestic wells was related to high boron concentrations (up to 57 mg/L) measured in the shallow aquifer from the industrial area of Castelluccio (Tuscany, Italy), where several factories are or were using boron compounds for their industrial processes. Since 2012 a geochemical and isotopic survey of stream, ground and waste waters, and sediment samples was performed. In addition, monthly geochemical surveys were carried out from January to September 2013, during which concentrations of boron up to 139 mg/L were measured. The geochemical dataset also included raw (borax and sodium boron-hydride) and anthropogenic materials (B-rich slags and muds stored in one of the local factories), the latter being, to the best of our knowledge, analyzed for the first time in this work for bulk and leachate boron concentration and isotopic ratios. The results highlighted that the high concentrations of boron found in the local shallow aquifer had unequivocally an anthropogenic source. It was suggested that prolonged interaction between industrial (presently stored at ground level or buried) by-products and waste and meteoric waters was likely the main process responsible of the groundwater contamination as supported by the analysis of the major solutes. The dispersion of the contaminant could not clearly be observed downward the shallow hydrogeological circuit. Consequently, the presence of other sources of boron in the industrial area of Castelluccio cannot be excluded. This would also explain the reason why no univocal results were obtained by the "1"1B/"1"0B isotopic ratios measured in water, sediment and (bulk and leachate) anthropogenic samples. To minimize the boron contamination a hydraulic barrier should be constructed where the highest concentrations of boron were measured. - Highlights: • High boron concentrations were measured in a groundwater system near Arezzo (Italy). • Several factories in the local

  1. Cygnus History

    International Nuclear Information System (INIS)

    Henderson, David J.; Gignac, Raymond E.; Good, Douglas E.; Hansen, Mark D.; Mitton, Charles V.; Nelson, Daniel S.; Ormond, Eugene C.; Cordova, Steve R.; Molina, Isidro; Smith, John R.; Rose, Evan A.

    2009-01-01

    The Cygnus Dual Beam Radiographic Facility consists of two identical radiographic sources: Cygnus 1 and Cygnus 2. This Radiographic Facility is located in an underground tunnel test area at the Nevada Test Site. The sources were developed to produce high-resolution images for dynamic plutonium experiments. This work will recount and discuss salient maintenance and operational issues encountered during the history of Cygnus. A brief description of Cygnus systems and rational for design selections will set the stage for this historical narrative. It is intended to highlight the team-derived solutions for technical problems encountered during extended periods of maintenance and operation. While many of the issues are typical to pulsed power systems, some of the solutions are unique. It is hoped that other source teams will benefit from this presentation, as well as other necessary disciplines (e.g., source users, system architects, facility designers and managers, funding managers, and team leaders)

  2. Developments in boron magnetic resonance imaging (MRI)

    International Nuclear Information System (INIS)

    Schweizer, M.

    1995-01-01

    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

  3. Da fantasia à História: folheando páginas revisteiras From fantasy to History: unfolding sources inside magazines

    Directory of Open Access Journals (Sweden)

    Ana Luiza Martins

    2003-01-01

    Full Text Available Este texto trata do uso da revista como fonte histórica, procurando apontar suas características de documento múltiplo para recuperação da História, insistindo na necessidade preliminar de sua crítica exaustiva, em função do caráter mercantil e/ou ideológico que preside tais publicações. Concomitantemente, levanta dois aspectos que demandam análise apurada: a segmentação que preside o periódico e que define sua linha editorial e as ilustrações que o compõe, sem perder de vista as seções que conformam a publicação. Toma como exemplo revistas paulistanas de 1890 a 1920.This article deals with the use of magazines as sources of History, trying to point out its characteristics as a multiple document serving to recover history, also stressing the need of a preliminary, exhaustive critical evaluation, due to the mercantile and/or ideological nature of these publications. Concomitantly, the paper reveals two aspects that deserve an accurate study involving the magazines: the target reading population, which defines its editorial line, and the illustrations, important part of its core, not forgetting to mention the specific sections that complete the publications. The examples studied are magazines issued in São Paulo City, within the period 1890/1920.

  4. Sources for the study of the history of the dominican studium generale in Krakow in the modern era. The state of research and research perspectives

    Directory of Open Access Journals (Sweden)

    Wiktor Szymborski

    2012-12-01

    Full Text Available Main objective of the essay under consideration was investigation and characterized most important source materials stocked at the Archive of the Cracow’s Dominican Province to present the history of their studium generale during the Modern period. Also, the current knowledge of a.m. period of studium generale was screened- out and some searching hypothesis were proposed concerning the history of the Cracow’s Dominican studium generale. The searching time frame have been limited to XVI up to XVII century. Taken into consideration, the current status of research works performed so far, one ought to stated that the Modern Epoch has not been searched out with the same consciousness compare to the Medieval one. As the most important printed source materials, one ought to account the documents issued by the general and provincial chapters of the Convent. The documents of the provincial chapters have been listed and screened by Father Fabian Madura, and were stocked as the typescript formats at the Cracow’s Dominican Convent Library. Based on the searched source materials of General Chapter of Dominican Convent at Cracow, it is possible to present the general overview of the convent education system and its changes in due time. Due to the records found it would be possible to identify – position and name – the Dominicans nominated to the Convent stadium generale. The most important manuscript stocked at the Cracow’s Dominican Convent Archive as the education system is concern, is so called Liber Studii Generalis cracoviensis (rkps 20. This manuscript covers the list of friars who have been nominated to work at stadium generale. A.m. document has to verify and compare with other sources. Taken into consideration above mention facts, it seems to be as most important searching activities to describe the convent society of the Cracow’s Dominicans. At the essay some detailed searching hypothesis were presented, such as searching and reviewing

  5. The history and source of particulate 137Cs and 239,240Pu deposition in sediments of the Ob River Delta, Siberia

    International Nuclear Information System (INIS)

    Sayles, F.L.; Livingston, H.D.; Panteleyev, G.P.

    1997-01-01

    This paper presents the first results of a project designed to examine the transfer of particle-associated artificial radionuclides down the Ob River in Siberia to its delta over the past 5 decades. The main sources include fallout from atmospheric nuclear weapons tests and weapons complexes and test sites of the Former Soviet Union in or near the Ob watershed. The approach is to measure the accumulation of the radionuclides in undisturbed delta sediments - obtaining a record of their deposition over time. These records were found in sediments of shallow lakes apart from, and connected to, the main channel. Sediment cores were collected in the summer of 1994 using a shallow draft catamaran to reach these lakes from a support ship in the main channel. Measurements are presented on the depth distributions of 137 Cs and Pu isotopes and their inventories in a series of dated sediment cores - including one from a location in the Taz Estuary (which does not receive Ob River sediments). Sediment dating was carried out using the excess 210 Pb technique. The results obtained are compared with known information on the temporal history of releases from the various sources and characteristics of the isotopic composition of the sources. The results show that good records of radionuclide deposition indicate that the major fraction of 137 Cs and Pu isotopes deposited in these delta sediments comes from atmospheric nuclear weapons test fallout - both delivered directly from the atmosphere and from downstream transport of watershed sediments. No more than 25% of the observed inventories could be derived from other sources

  6. Study of extraction-spectrophotometric micro-determination of boron with methylene blue and its application

    International Nuclear Information System (INIS)

    Zhu Daohong

    1990-08-01

    A sensitive extraction-spectrophotometric method for microdetermination of boron with methylene blue was investigated. The method was based on the extraction of a BF 4 - -methylene blue complex into dichloroethane. Boron was determined directly by measuring the absorbance at 658 nm. The calibration graph was linear over the range of 2.5 x 10 -9 to 8 x 10 -8 g/mL. The blank, mechanism of the reactions, interference of other ions and some optimum conditions of the method were studied in detail. The main source of the blank resulted from methylene blue and the complex of F - -methylene blue. In order to reduce the blank, the amounts of methylene blue, H 2 SO 4 and HF were used as less as possible. Only one to one complex BF 4 - -methylene blue was formed in the medium of H 2 SO 4 . About 90% of methylene blue and F - -methylene blue complex was removre with 5 ml of water and only a little amount of BF 4 -methylene blue complex was decomposed. The extraction-spectrophotometric method with methylene blue was first applied to the microdetermination of boron in sodium metal and UF 6 . The sample of sodium metal was taken and weighed in the glovebox filled with argon. Then sodium metal was oxidized, hydrolyzed, netralized and fluorizated with H 2 O, H 2 SO 4 and HF, respectively. The 0.5 ppm of boron in sodium metal was determined with a relative error about ±4%. This method can be applied to the determination of boron in sodium metal, sodium sulfate and sodium hydroxide at diffeent grades. The species of boron in the hydrolysate of UF 6 is BF 4 - anion, so the sample can be directly analyzed. Boron contents in the range of 0.1 to 0.5 ppm was determined with a relative error about ±3%. Six samples could be analysed in 2h

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

    Science.gov (United States)

    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.

  8. Investigation of boron extraction process with aid magnesium hydroxide from mother liquor of boron production

    International Nuclear Information System (INIS)

    Balapanova, B.S.; Zhajmina, R.E.; Serazetdinov, D.Z.

    1988-01-01

    Conditions of boron - magnesium concentrate preparation from mother liquor by coprecipitation of borate - ions by magnesium hydroxide are investigated. It is shown that boron - magnesium concentrate and products of its heat treatment at 100 - 500 deg C in water are dissolved partially, and in ammonium citrate - practically completely. Suppositions are made on the composition of the product prepared, on the the structure of its crystal lattice and the processes taking place in it during heat treatment. The conclusion is made on the perspectiveness of processing of mother liquor of boron industry for boron - magnesium concentrate

  9. Measuring the sensitivity of a boron-lined ion chamber

    International Nuclear Information System (INIS)

    Barton, D.M.

    1992-03-01

    Boron-lined ion chambers are used to monitor external neutron flux from fissionable materials assembled at the Los Alamos Critical Assembly Experiment Facility. The sensitivity of these chambers must be measured periodically in order to detect changes in filling gas and to evaluate other factors that may affect chamber performance. We delineate a procedure to measure ion chamber response using a particular neutron source ( 239 PuBe) in a particular moderating geometry of polyethylene. We also discuss use of the amplifier, high-voltage power supply, recorders, and scram circuits that comprise the complete ion chamber monitoring system

  10. PAMELA measurements of the boron and carbon spectra

    International Nuclear Information System (INIS)

    Mori, N; Adriani, O; Bongi, M; Barbarino, G C; Bazilevskaya, G A; Bellotti, R; Bruno, A; Boezio, M; Bonvicini, V; Carbone, R; Bogomolov, E A; Bottai, S; Cafagna, F; Campana, D; Carlson, P; Casolino, M; De Donato, C; De Santis, C; De Simone, N; Castellini, G

    2015-01-01

    The satellite-borne PAMELA experiment is aimed at precision measurements of the charged light component of the cosmic-ray spectrum, with a particular focus on antimatter. It consists of a magnetic spectrometer, a time-of-flight system, an electromagnetic calorimeter with a tail catcher scintillating layer, an anticoincidence system and a neutron detector. PAMELA has measured the absolute fluxes of boron and carbon and the B/C ratio, which plays a central role in galactic propagation studies in order to derive the injection spectra at sources from measurements at Earth. In this paper, the data analysis techniques and the final results are presented. (paper)

  11. Cathodoluminescence of cubic boron nitride

    International Nuclear Information System (INIS)

    Tkachev, V.D.; Shipilo, V.B.; Zaitsev, A.M.

    1985-01-01

    Three types of optically active defect were observed in single-crystal and polycrystalline cubic boron nitride (β-BN). An analysis of the temperature dependences of the intensity, half-width, and energy shift of a narrow zero-phonon line at 1.76 eV (GC-1 center) made it possible to interpret the observed cathodoluminescence spectra as an optical analog of the Moessbauer effect. A comparison of the results obtained in the present study with the available data on diamond single crystals made it possible to identify the observed GC-1 center as a nitrogen vacancy. It was concluded that optical Moessbauer-type spectra can be used to analyze structure defects in the crystal lattice of β-BN

  12. Urea route to coat inorganic nanowires, carbon fibers and nanotubes by boron nitride

    International Nuclear Information System (INIS)

    Gomathi, A.; Ramya Harika, M.; Rao, C.N.R.

    2008-01-01

    A simple route involving urea as the nitrogen source has been employed to carry out boron nitride coating on carbon fibers, multi-walled carbon nanotubes and inorganic nanowires. The process involves heating the carbon fibers and nanotubes or inorganic nanowires in a mixture of H 3 BO 3 and urea, followed by a heat treatment at 1000 deg. C in a N 2 atmosphere. We have been able to characterize the BN coating by transmission electron microscopy as well as X-ray photoelectron spectroscopy. The urea decomposition route affords a simple method to coat boron nitride on one-dimensional nanostructures

  13. Behaviour of boron in Mandovi estuary (Goa)

    Digital Repository Service at National Institute of Oceanography (India)

    Shirodkar, P.V.; Anand, S.P.

    and alkalinity gave positive correlations with a linear variation. Though the overall behavioural pattern of boron indicated non-conservative nature, it showed a quasi-conservative character during premonsoon and a non-conservative during rest of the seasons...

  14. Internal stress control of boron thin film

    International Nuclear Information System (INIS)

    Satomi, N.; Kitamura, M.; Sasaki, T.; Nishikawa, M.

    1998-01-01

    The occurrence of stress in thin films has led to serious stability problems in practical use. We have investigated the stress in the boron films to find the deposition condition of the boron films with less stress. It was found that the stress in the boron film varies sufficiently from compressive to tensile stress, that is from -1.0 to 1.4 GPa, depending on the evaporation conditions, such as deposition rate and the substrate temperature. Hydrogen ion bombardment resulted in the enhancement of the compressive stress, possibly due to ion peening effect, while under helium ion bombardment, stress relief was observed. The boron film with nearly zero stress was obtained by the evaporation at a deposition rate of 0.5 nm s -1 and substrate temperature of 300 C. (orig.)

  15. Internal stress control of boron thin film

    Energy Technology Data Exchange (ETDEWEB)

    Satomi, N.; Kitamura, M.; Sasaki, T.; Nishikawa, M. [Osaka Univ., Suita (Japan). Graduate Sch. of Eng.

    1998-09-01

    The occurrence of stress in thin films has led to serious stability problems in practical use. We have investigated the stress in the boron films to find the deposition condition of the boron films with less stress. It was found that the stress in the boron film varies sufficiently from compressive to tensile stress, that is from -1.0 to 1.4 GPa, depending on the evaporation conditions, such as deposition rate and the substrate temperature. Hydrogen ion bombardment resulted in the enhancement of the compressive stress, possibly due to ion peening effect, while under helium ion bombardment, stress relief was observed. The boron film with nearly zero stress was obtained by the evaporation at a deposition rate of 0.5 nm s{sup -1} and substrate temperature of 300 C. (orig.) 12 refs.

  16. Determination of boron in amorphous alloys

    Energy Technology Data Exchange (ETDEWEB)

    Grazhulene, S.S.; Grossman, O.V.; Kuntscher, K.K.; Malygina, L.I.; Muller, E.N.; Telegin, G.F.

    1985-10-01

    In the determination of boron in amorphous alloys containingFe, Co, B, Si, Ni, and P having unusal magnetic and electrical properties, precise analysis and rapid analysis are necessary. To improve the metrological properties of the existing procedure, to find a rapid determination of boron in amorphous alloys, and to verify the accuracy of the results, in the present work the optimization of the photometric determination after extraction of the BF/sup -//sub 4/ ion pair with methylene blue has been studied, and a boron determination by flame photometry using selective methylation has been developed. The determination of boron by the flame photometric and spectrophotometric methods is shown. When a highly precise determination is needed, the spectrophotometric procedure can be used. This procedure is distinguished by its labor intensity and duration. When the need for reproducibility is less severe, the rapid flame photometric procedure is best.

  17. Boron adsorption on hematite and clinoptilolite

    International Nuclear Information System (INIS)

    Gainer, G.M.

    1993-01-01

    This thesis describes experiments performed to determine the suitability of boron as a potential reactive tracer for use in saturated-zone C-well reactive tracer studies for the Yucca Mountain Project (YMP). Experiments were performed to identify the prevalent sorption mechanism of boron and to determine adsorption of boron on hematite and clinoptilolite as a function of pH. These minerals are present in the Yucca Mountain tuff in which the C-well studies will be conducted. Evaluation of this sorption mechanism was done by determining the equilibration time of boron-mineral suspensions, by measuring changes in equilibrium to titrations, and by measuring electrophoretic mobility. Experiments were performed with the minerals suspended in NaCl electrolytes of concentrations ranging from 0.1 N NaCl to 0.001 N NaCl. Experimentalconditions included pH values between 3 and 12 and temperature of about 38 degrees C

  18. Boron-isotope fractionation in plants

    Energy Technology Data Exchange (ETDEWEB)

    Marentes, E [Univ. of Guelph, Dept. of Horticultural Science, Guelph, Ontario (Canada); Vanderpool, R A [USDA/ARS Grand Forks Human Nutrition Research Center, Grand Forks, North Dakota (United States); Shelp, B J [Univ. of Guelph, Dept. of Horticultural Science, Guelph, Ontario (Canada)

    1997-10-15

    Naturally-occurring variations in the abundance of stable isotopes of carbon, nitrogen, oxygen, and other elements in plants have been reported and are now used to understand various physiological processes in plants. Boron (B) isotopic variation in several plant species have been documented, but no determination as to whether plants fractionate the stable isotopes of boron, {sup 11}B and {sup 10}B, has been made. Here, we report that plants with differing B requirements (wheat, corn and broccoli) fractionated boron. The whole plant was enriched in {sup 11}B relative to the nutrient solution, and the leaves were enriched in {sup 10}B and the stem in {sup 11}B relative to the xylem sap. Although at present, a mechanistic role for boron in plants is uncertain, potential fractionating mechanisms are discussed. (author)

  19. Boron-isotope fractionation in plants

    International Nuclear Information System (INIS)

    Marentes, E.; Vanderpool, R.A.; Shelp, B.J.

    1997-01-01

    Naturally-occurring variations in the abundance of stable isotopes of carbon, nitrogen, oxygen, and other elements in plants have been reported and are now used to understand various physiological processes in plants. Boron (B) isotopic variation in several plant species have been documented, but no determination as to whether plants fractionate the stable isotopes of boron, 11 B and 10 B, has been made. Here, we report that plants with differing B requirements (wheat, corn and broccoli) fractionated boron. The whole plant was enriched in 11 B relative to the nutrient solution, and the leaves were enriched in 10 B and the stem in 11 B relative to the xylem sap. Although at present, a mechanistic role for boron in plants is uncertain, potential fractionating mechanisms are discussed. (author)

  20. Superplastic boronizing of duplex stainless steel under dual compression method

    International Nuclear Information System (INIS)

    Jauhari, I.; Yusof, H.A.M.; Saidan, R.

    2011-01-01

    Highlights: → Superplastic boronizing. → Dual compression method has been developed. → Hard boride layer. → Bulk deformation was significantly thicker the boronized layer. → New data on boronizing could be expanded the application of DSS in industries. - Abstract: In this work, SPB of duplex stainless steel (DSS) under compression method is studied with the objective to produce ultra hard and thick boronized layer using minimal amount of boron powder and at a much faster boronizing time as compared to the conventional process. SPB is conducted under dual compression methods. In the first method DSS is boronized using a minimal amount of boron powder under a fix pre-strained compression condition throughout the process. The compression strain is controlled in such a way that plastic deformation is restricted at the surface asperities of the substrate in contact with the boron powder. In the second method, the boronized specimen taken from the first mode is compressed superplastically up to a certain compressive strain under a certain strain rate condition. The process in the second method is conducted without the present of boron powder. As compared with the conventional boronizing process, through this SPB under dual compression methods, a much harder and thicker boronized layer thickness is able to be produced using a minimal amount of boron powder.

  1. Superplastic boronizing of duplex stainless steel under dual compression method

    Energy Technology Data Exchange (ETDEWEB)

    Jauhari, I., E-mail: iswadi@um.edu.my [Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Yusof, H.A.M.; Saidan, R. [Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2011-10-25

    Highlights: {yields} Superplastic boronizing. {yields} Dual compression method has been developed. {yields} Hard boride layer. {yields} Bulk deformation was significantly thicker the boronized layer. {yields} New data on boronizing could be expanded the application of DSS in industries. - Abstract: In this work, SPB of duplex stainless steel (DSS) under compression method is studied with the objective to produce ultra hard and thick boronized layer using minimal amount of boron powder and at a much faster boronizing time as compared to the conventional process. SPB is conducted under dual compression methods. In the first method DSS is boronized using a minimal amount of boron powder under a fix pre-strained compression condition throughout the process. The compression strain is controlled in such a way that plastic deformation is restricted at the surface asperities of the substrate in contact with the boron powder. In the second method, the boronized specimen taken from the first mode is compressed superplastically up to a certain compressive strain under a certain strain rate condition. The process in the second method is conducted without the present of boron powder. As compared with the conventional boronizing process, through this SPB under dual compression methods, a much harder and thicker boronized layer thickness is able to be produced using a minimal amount of boron powder.

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

    International Nuclear Information System (INIS)

    Wielopolski, L.; Ciesielski, B.

    1995-01-01

    In Boron Neutron Capture Therapy (BNCT) the dominant dose delivered to the tumor is due to α and 7 Li charged particles resulting from a neutron capture by 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

  3. Effects of water quality parameters on boron toxicity to Ceriodaphnia dubia.

    Science.gov (United States)

    Dethloff, Gail M; Stubblefield, William A; Schlekat, Christian E

    2009-07-01

    The potential modifying effects of certain water quality parameters (e.g., hardness, alkalinity, pH) on the acute toxicity of boron were tested using a freshwater cladoceran, Ceriodaphnia dubia. By comparison, boron acute toxicity was less affected by water quality characteristics than some metals (e.g., copper and silver). Increases in alkalinity over the range tested did not alter toxicity. Increases in water hardness appeared to have an effect with very hard waters (>500 mg/L as CaCO(3)). Decreased pH had a limited influence on boron acute toxicity in laboratory waters. Increasing chloride concentration did not provide a protective effect. Boron acute toxicity was unaffected by sodium concentrations. Median acute lethal concentrations (LC(50)) in natural water samples collected from three field sites were all greater than in reconstituted laboratory waters that matched natural waters in all respects except for dissolved organic carbon. Water effect ratios in these waters ranged from 1.4 to 1.8. In subsequent studies using a commercially available source of natural organic matter, acute toxicity decreased with increased dissolved organic carbon, suggesting, along with the natural water studies, that dissolved organic carbon should be considered further as a modifier of boron toxicity in natural waters where it exceeds 2 mg/L.

  4. Boron-rich oligomers for BNCT

    International Nuclear Information System (INIS)

    Gula, M.; Perleberg, O.; Gabel, D.

    2000-01-01

    The synthesis of two BSH derivatives is described, which can be used for oligomerization in DNA-synthesizers. Synthesis pathways lead to final products in five and six steps, respectively. Because of chirality interesting results were expected. NMR-measurements confirm this expectation. Possible oligomers with high concentrations of boron can be attached to biomolecules. These oligomers can be explored with several imaging methods (EELS, PEM) to determine the lower detection limit of boron with these methods. (author)

  5. Rare earth-iron-boron premanent magnets

    International Nuclear Information System (INIS)

    Ghendehari, M.H.

    1988-01-01

    This patent describes a method for producing rare earth-iron-boron permanent magnets containing added rare earth oxide, comprising the steps of: (a) mixing a particulate alloy containing at least one rare earth metal, iron, and boron with at least one particulate rare earth oxide; (b) aligning magnetic domains of the mixture in a magnetic field; (c) compacting the aligned mixture to form a shape; and (d) sintering the compacted shape

  6. Quantitative analysis of boron by neutron radiography

    International Nuclear Information System (INIS)

    Bayuelken, A.; Boeck, H.; Schachner, H.; Buchberger, T.

    1990-01-01

    The quantitative determination of boron in ores is a long process with chemical analysis techniques. As nuclear techniques like X-ray fluorescence and activation analysis are not applicable for boron, only the neutron radiography technique, using the high neutron absorption cross section of this element, can be applied for quantitative determinations. This paper describes preliminary tests and calibration experiments carried out at a 250 kW TRIGA reactor. (orig.) [de

  7. Biomedical irradiation system for boron neutron capture therapy at the Kyoto University Reactor

    International Nuclear Information System (INIS)

    Kobayashi, T.; Kanda, K.; Ujeno, Y.; Ishida, M.R.

    1990-01-01

    Physics studies related to radiation source, spectroscopy, beam quality, dosimetry, and biomedical applications using the Kyoto University Reactor Heavy Water Facility are described. Also, described are a Nickel Mirror Neutron Guide Tube and a Super Mirror Neutron Guide Tube that are used both for the measurement of boron concentration in phantom and living tissue and for precise measurements of neutron flux in phantom in the presence of both light and heavy water. Discussed are: (1) spectrum measurements using the time of flight technique, (2) the elimination of gamma rays and fast neutrons from a thermal neutron irradiation field, (3) neutron collimation without producing secondary gamma rays, (4) precise neutron flux measurements, dose estimation, and the measurement of boron concentration in tumor and its periphery using guide tubes, (5) the dose estimation of boron-10 for the first melanoma patient, and (6) special-purpose biological irradiation equipment. Other related subjects are also described

  8. Biomedical irradiation system for boron neutron capture therapy at the Kyoto University reactor

    International Nuclear Information System (INIS)

    Kobayashi, T.; Kanda, K.; Ujeno, Y.; Ishida, M.R.

    1990-01-01

    Physics studies related to radiation source, spectroscopy, beam quality, dosimetry, and biomedical applications using the Kyoto University Reactor Heavy Water Facility are described. Also, described are a Nickel Mirror Neutron Guide Tube and a Super Mirror Neutron Guide Tube that are used both for the measurement of boron concentration in phantom and living tissue and for precise measurements of neutron flux in phantom in the presence of both light and heavy water. Discussed are: (1) spectrum measurements using the time of flight technique, (2) the elimination of gamma rays and fast neutrons from a thermal neutron irradiation field, (3) neutron collimation without producing secondary gamma rays, (4) precise neutron flux measurements, dose estimation, and the measurement of boron concentration in tumor and its periphery using guide tubes, (5) the dose estimation of boron-10 for the first melanoma patient, and (6) special-purpose biological irradiation equipment. Other related subjects are also described

  9. Discharge cleaning on TFTR after boronization

    International Nuclear Information System (INIS)

    Mueller, D.; Dylla, H.F.; LaMarche, P.H.; Bell, M.G.; Blanchard, W.; Bush, C.E.; Gentile, C.; Hawryluk, R.J.; HIll, K.W.; Janos, A.C.; Jobes, F.C; Owens, D.K.; Pearson, G.; Schivell, J.; Ulrickson, M.A.; Vannoy, C.; Wong, K.L.

    1991-05-01

    At the beginning of the 1990 TFTR experimental run, after replacement of POCO-AXF-5Q graphite tiles on the midplane of the bumper limiter by carbon fiber composite (CFC) tiles and prior to any Pulse Discharge Cleaning (PDC), boronization was performed. Boronization is the deposition of a layer of boron and carbon on the vacuum vessel inner surface by a glow discharge in a diborane, methane and helium mixture. The amount of discharge cleaning required after boronization was substantially reduced compared to that which was needed after previous openings when boronization was not done. Previously, after a major shutdown, about 10 5 low current (∼20 kA) Taylor Discharge Cleaning (TDC) pulses were required before high current (∼400 kA) aggressive Pulse Discharge Cleaning (PDC) pulses could be performed successfully. Aggressive PDC is used to heat the limiters from the vessel bakeout temperature of 150 degrees C to 250 degrees C for a period of several hours. Heating the limiters is important to increase the rate at which water is removed from the carbon limiter tiles. After boronization, the number of required TDC pulses was reduced to <5000. The number of aggressive PDC pulses required was approximately unchanged. 14 refs., 1 tab

  10. Boronization on NSTX using Deuterated Trimethylboron

    International Nuclear Information System (INIS)

    Blanchard, W.R.; Gernhardt, R.C.; Kugel, H.W.; LaMarche, P.H.

    2002-01-01

    Boronization on the National Spherical Torus Experiment (NSTX) has proved to be quite beneficial with increases in confinement and density, and decreases in impurities observed in the plasma. The boron has been applied to the interior surfaces of NSTX, about every 2 to 3 weeks of plasma operation, by producing a glow discharge in the vacuum vessel using deuterated trimethylboron (TMB) in a 10% mixture with helium. Special NSTX requirements restricted the selection of the candidate boronization method to the use of deuterated boron compounds. Deuterated TMB met these requirements, but is a hazardous gas and special care in the execution of the boronization process is required. This paper describes the existing GDC, Gas Injection, and Torus Vacuum Pumping System hardware used for this process, the glow discharge process, and the automated control system that allows for remote operation to maximize both the safety and efficacy of applying the boron coating. The administrative requirements and the detailed procedure for the setup, operation and shutdown of the process are also described

  11. Innovative boron nitride-doped propellants

    Directory of Open Access Journals (Sweden)

    Thelma Manning

    2016-04-01

    Full Text Available The U.S. military has a need for more powerful propellants with balanced/stoichiometric amounts of fuel and oxidants. However, balanced and more powerful propellants lead to accelerated gun barrel erosion and markedly shortened useful barrel life. Boron nitride (BN is an interesting potential additive for propellants that could reduce gun wear effects in advanced propellants (US patent pending 2015-026P. Hexagonal boron nitride is a good lubricant that can provide wear resistance and lower flame temperatures for gun barrels. Further, boron can dope steel, which drastically improves its strength and wear resistance, and can block the formation of softer carbides. A scalable synthesis method for producing boron nitride nano-particles that can be readily dispersed into propellants has been developed. Even dispersion of the nano-particles in a double-base propellant has been demonstrated using a solvent-based processing approach. Stability of a composite propellant with the BN additive was verified. In this paper, results from propellant testing of boron nitride nano-composite propellants are presented, including closed bomb and wear and erosion testing. Detailed characterization of the erosion tester substrates before and after firing was obtained by electron microscopy, inductively coupled plasma and x-ray photoelectron spectroscopy. This promising boron nitride additive shows the ability to improve gun wear and erosion resistance without any destabilizing effects to the propellant. Potential applications could include less erosive propellants in propellant ammunition for large, medium and small diameter fire arms.

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

    Energy Technology Data Exchange (ETDEWEB)

    Mannix, A. J.; Zhou, X. -F.; Kiraly, B.; Wood, J. D.; Alducin, D.; Myers, B. D.; Liu, X.; Fisher, B. L.; Santiago, U.; Guest, J. R.; Yacaman, M. J.; Ponce, A.; Oganov, A. R.; Hersam, M. C.; Guisinger, N. P.

    2015-12-17

    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.

  13. Development of magnetic resonance technology for noninvasive boron quantification

    International Nuclear Information System (INIS)

    Bradshaw, K.M.

    1990-11-01

    Boron magnetic resonance imaging (MRI) and spectroscopy (MRS) were developed in support of the noninvasive boron quantification task of the Idaho National Engineering Laboratory (INEL) Power Burst Facility/Boron Neutron Capture Therapy (PBF/BNCT) program. The hardware and software described in this report are modifications specific to a GE Signa trademark MRI system, release 3.X and are necessary for boron magnetic resonance operation. The technology developed in this task has been applied to obtaining animal pharmacokinetic data of boron compounds (drug time response) and the in-vivo localization of boron in animal tissue noninvasively. 9 refs., 21 figs

  14. Proceedings of workshop on 'boron science and boron neutron capture therapy'

    Energy Technology Data Exchange (ETDEWEB)

    Kitaoka, Y. [ed.

    1998-12-01

    This volume contains the abstracts and programs of the 8th (1996), 9th (1997) and 10th (1998) of the workshop on 'the Boron Science and Boron Neutron Capture Therapy' and the recent progress reports especially subscribed. The 11 of the presented papers are indexed individually. (J.P.N.)

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

    Science.gov (United States)

    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...

  16. Research of boron conversion coating in neutron detector with boron deposited GEM

    International Nuclear Information System (INIS)

    Ye Di; Sun Zhijia; Zhou Jianrong; Wang Yanfeng; Yang Guian; Xu Hong; Chen Yuanbai; Xiao Yu; Diao Xungang

    2014-01-01

    GEM is a flourishing new gas detector and nowadays its technology become more mature. It has outstanding properties, such as excellent position resolution, high counting rate, radiation resistance, simple and flexible signal readout, can be large-area detector, wide application range. Detector with boron deposited GEM uses multilayer GEM with deposited boron film as neutron conversion carrier which reads out the information of neutron shot from the readout electrode with gas amplification from every GEM layer. The detector is high performance which can meet the demands of neutron detector of a new generation. Boron deposited neutron conversion electrode with boron deposited cathode and GEM included is the core part of the detector. As boron is a high-melting-point metalloid (> 2 000 ℃), electroplating and thermal evaporation are inappropriate ways. So finding a way to deposit boron on electrode which can meet the demands become a key technology in the development of neutron detector with boron deposited GEM. Compared with evaporation, sputtering has features such as low deposition temperature, high film purity, nice adhesive, thus is appropriate for our research. Magnetron sputtering is a improved way of sputtering which can get lower sputtering air pressure and higher target voltage, so that we can get better films. Through deposit process, the research uses magnetron sputtering to deposit pure boron film on copper electrode and GEM film. This method can get high quality, nice adhere, high purity, controllable uniformity, low cost film with high speed film formation. (authors)

  17. The study of high-boron steel and high-boron cast iron used for shield

    International Nuclear Information System (INIS)

    Pan Xuerong; Lu Jixin; Wen Yaozeng; Wang Zhaishu; Cheng Jiantin; Cheng Wen; Shun Danqi; Yu Jinmu

    1996-12-01

    The smelting, forging, heat-treatment technology and the mechanical properties of three kinds of high-boron steels (type 1: 0.5% boron; type 2: 0.5% boron and 4% or 2% nickel; type 3: 0.5% boron, 0.5% nickel and 0.5% molybdenum) were studied. The test results show that the technology for smelting, forging and heat-treatment (1050 degree C/0.5 h water cooled + 810 degree C/1 h oil cooled) in laboratory is feasible. Being sensitive to notch, the impact toughness of high-boron steel type 1 is not steady and can not meet the technology requirements on mechanical properties. The mechanical properties of both high-boron steel type 2 and type 3 can meet the technological requirements. The smelting technology of high-boron casting iron containing 0.5% boron was researched. The tests show that this casting iron can be smelted in laboratory and its properties can basically satisfy the technology requirements. (10 refs., 6 figs., 11 tab.)

  18. Real-time boronization in PBX-M using erosion of solid boronized targets

    International Nuclear Information System (INIS)

    Kugel, H.W.; Timberlake, J.; Bell, R.; LeBlanc, B.; Okabayashi, M.; Paul, S.; Tighe, W.; Hirooka, Y.

    1994-11-01

    Thirty one real-time boronizations were applied to PBX-M using the plasma erosion of solid target probes. More than 17 g of boron were deposited in PBX-M using this technique. The probes were positioned at the edge plasma to optimize vaporization and minimize spallation. Auger depth profile analysis of poloidal and toroidal deposition sample coupon arrays indicate that boron was transported by the plasma around the torus and deep into the divertors. During discharges with continuous real-time boronization, low-Z and high-Z impurities decreased rapidly as plasma surfaces were covered during the first 20-30 discharges. After boronization, a short-term improvement in plasma conditions persisted prior to significant boron erosion from plasma surfaces, and a longer term, but less significant improvement persisted as boron farther from the edge continued gettering. Real-time solid target boronization has been found to be very effective for accelerating conditioning to new regimes and maintaining high performance plasma conditions

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

    Science.gov (United States)

    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.

  20. A quantitative comparison between electrocoagulation and chemical coagulation for boron removal from boron-containing solution

    International Nuclear Information System (INIS)

    Yilmaz, A. Erdem; Boncukcuoglu, Recep; Kocakerim, M. Muhtar

    2007-01-01

    This paper provides a quantitative comparison of electrocoagulation and chemical coagulation approaches based on boron removal. Electrocoagulation process delivers the coagulant in situ as the sacrificial anode corrodes, due to a fixed current density, while the simultaneous evolution of hydrogen at the cathode allows for pollutant removal by flotation. By comparison, conventional chemical coagulation typically adds a salt of the coagulant, with settling providing the primary pollutant removal path. Chemical coagulation was carried out via jar tests using aluminum chloride. Comparison was done with the same amount of coagulant between electrocoagulation and chemical coagulation processes. Boron removal obtained was higher with electrocoagulation process. In addition, it was seen that chemical coagulation has any effect for boron removal from boron-containing solution. At optimum conditions (e.g. pH 8.0 and aluminum dose of 7.45 g/L), boron removal efficiencies for electrocoagulation and chemical coagulation were 94.0% and 24.0%, respectively

  1. A quantitative comparison between electrocoagulation and chemical coagulation for boron removal from boron-containing solution

    Energy Technology Data Exchange (ETDEWEB)

    Yilmaz, A. Erdem [Atatuerk University, Faculty of Engineering, Department of Environmental Engineering, 25240 Erzurum (Turkey)], E-mail: aerdemy@atauni.edu.tr; Boncukcuoglu, Recep [Atatuerk University, Faculty of Engineering, Department of Environmental Engineering, 25240 Erzurum (Turkey); Kocakerim, M. Muhtar [Atatuerk University, Faculty of Engineering, Department of Chemical Engineering, 25240 Erzurum (Turkey)

    2007-10-22

    This paper provides a quantitative comparison of electrocoagulation and chemical coagulation approaches based on boron removal. Electrocoagulation process delivers the coagulant in situ as the sacrificial anode corrodes, due to a fixed current density, while the simultaneous evolution of hydrogen at the cathode allows for pollutant removal by flotation. By comparison, conventional chemical coagulation typically adds a salt of the coagulant, with settling providing the primary pollutant removal path. Chemical coagulation was carried out via jar tests using aluminum chloride. Comparison was done with the same amount of coagulant between electrocoagulation and chemical coagulation processes. Boron removal obtained was higher with electrocoagulation process. In addition, it was seen that chemical coagulation has any effect for boron removal from boron-containing solution. At optimum conditions (e.g. pH 8.0 and aluminum dose of 7.45 g/L), boron removal efficiencies for electrocoagulation and chemical coagulation were 94.0% and 24.0%, respectively.

  2. Biodistribution, toxicity and efficacy of a boronated porphyrin for boron neutron capture therapy

    International Nuclear Information System (INIS)

    Miura, Michiko; Micca, P.; Fairchild, R.; Slatkin, D.; Gabel, D.

    1992-01-01

    Boron-containing porphyrins may be useful for boron neutron capture therapy (BNCT) in the treatment of brain tumors. Porphyrins have been shown to accumulate in tumor tissue and to be essentially excluded from normal brain. However, problems of toxicity may prevent some boron-containing porphyrins from being considered for BNCT. The authors have synthesized the boronated porphyrin 2,4-bis-vinyl-o-nidocarboranyl-deuteroporphyrin IX (VCDP). Preliminary studies in tumor-bearing mice showed considerable uptake of boron at a total dose of 150 μg/gbw with low mortality. They now report that a total dose to mice of ∼ 275 μg VCDP/gbw administered in multiple intraperitoneal (ip) injections can provide 40-50μg B per gram of tumor with acceptable toxicity. Toxicity experiments and a preliminary trial of BNCT in mice given such doses are also reported

  3. Redistribution of boron in leaves reduces boron toxicity.

    Science.gov (United States)

    Reid, Robert J; Fitzpatrick, Kate L

    2009-11-01

    High soil boron (B) concentrations lead to the accumulation of B in leaves, causing the development of necrotic regions in leaf tips and margins, gradually extending back along the leaf. Plants vary considerably in their tolerance to B toxicity, and it was recently discovered that one of the tolerance mechanisms involved extrusion of B from the root. Expression of a gene encoding a root B efflux transporter was shown to be much higher in tolerant cultivars. In our current research we have shown that the same gene is also upregulated in leaves. However, unlike in the root, the increased activity of the B efflux transporter in the leaves cannot reduce the tissue B concentration. Instead, we have shown that in tolerant cultivars, these transporters redistribute B from the intracellular phase where it is toxic, into the apoplast which is much less sensitive to B. These results provide an explanation of why different cultivars with the same leaf B concentrations can show markedly different toxicity symptoms. We have also shown that rain can remove a large proportion of leaf B, leading to significant improvements of growth of both leaves and roots.

  4. Boron-containing thioureas for neutron capture therapy

    International Nuclear Information System (INIS)

    Ketz, H.

    1993-01-01

    Melanin is produced in large amounts in malignant melanotic melanomas. Because thiourea compounds are covalently incorporated into melanin during its biosynthesis, the preparation of boronated thiourea-derivatives is of particular interest for the BNCT (Boron Neutron Capture Therapy). Accumulation of boron in tumors by means of boronated thiourea-derivatives may therefore provide levels of 10 B which are useful for BNCT. In BNCT the tumor containing the boron compound is irradiated with epithermal neutrons to generate He- and Li-nuclei from the 10 B which can then destroy the tumor cells. Because of the short ranges of these particles (approximately one cell diameter) the damage will be almost exclusively confined to the tumor leaving normal tissue unharmed. High accumulation of 2-mercapto-1-methylimidazole (methimazole) in melanotic melanomas has been described in the literature. Boronated derivatives of methimazole were therefore synthesized. Boron was in the form of a boronic acid, a nido-carbonate and a mercaptoundeca hydro-closo-dodecaborate (BSH). The synthesis of the boron cluster derivatives of methimazole (nido-carborate- and BSH-derivatives) with 9 resp. 12 boron atoms in the molecule were expected to achieve higher concentrations of boron in the tumor than in the case of the boronic acid compound with its single boron atom. (orig.) [de

  5. List of subscribers as the source of data on book history and the history of reading: case study of book subscribers' lists printed in Dalmatia in the early 19th century

    Directory of Open Access Journals (Sweden)

    Jelena Lakuš

    2013-02-01

    Full Text Available Customer networks or lists of subscribers as a new publishing phenomenon first occurred in Dalmatia in the early 19th century. It was a model of collective funding of book, magazine and newspaper publishing, which gradually replaced the earlier system of individual patronage. It resulted in the publication of lists of subscribers that contained the names of all those who financially supported the printing of a book. The data on names of subscribers, their occupation, place of residence and number of copies ordered, which was the usual content of subscribers, lists, make them very valuable sources for research on the history of books and reading. This paper tries to show the research potential of such lists by presenting a case-study of five preserved and available subscribers' lists found in publications printed between 1835 and 1848 in the Zadar print shop of Battara brothers. The paper analyses the quantitative data on subscribers, their geographical distribution, professional profile and gender, which does not exhaust their research potential in full. The analysis has shown that despite the austere educational opportunities, high incidence of unemployment, and many other limitations, there were people who treasured the written word. The subscribers mostly came from coastal cities like Zadar, Split and Dubrovnik, which were the most important publishing and cultural centres. Even though the subscribers came from Austria, Military Border, Italy, Croatia proper and Slavonia, as well as Bosnia and Herzegovina, which was then part of the Ottoman Empire, they make up only one eight of the total number of subscribers in the corpus. The subscribers are both Roman-Catholic and Orthodox, who mostly subscribed to books printed in the Cyrillic script. The subscribers come from a wide range of professions, mostly from the church circles in Dalmatia, and the fewest of them were professors and teachers, members of the army and the police. As expected

  6. Implementation of new capacities in TRAC-BF1/NEM for the simulation of transient with injection of boron; Implementacion de nuevas capacidades en TRAC-BF1/NEM para la simulacion de transitorios con inyeccion de Boro

    Energy Technology Data Exchange (ETDEWEB)

    Jambrina, A.; Barrachina, T.; Miro, R.; Verdu, G.

    2011-07-01

    This article is a step in the simulation of the injection, transport and mixing of boron in the reactor, increasing the capabilities of the TRACBF1/NEM code. This article presents the changes in the source code for TRACBF1/NEM, to be able to simulate the injection of boron in a more realistic way.

  7. THE HISTORY OF ESTABLISHMENT OF THE NATURAL SOURCES DOSIMETRY LABORATORY IN THE INSTITUTE OF RADIATION HYGIENE AFTER PROFESSOR P.V. RAMZAEV, 1987–2005

    Directory of Open Access Journals (Sweden)

    I. P. Stamat

    2016-01-01

    Full Text Available The first 5–7 years of the period under review in the history of the Natural Sources Dosimetry Laboratory happened to be in very hard period, which had a time the entire country. A severe funding reduction of the Institute in the 90-s created a threat of loss of the most active and highly professional middle-aged specialists. In these conditions, the only and the most efficient way to maintain Institute as a scientific establishment was to organize the Federal Radiological Center under the guidance of Dr. A.N. Barkovskiy. The Federal Radiological Center consisted of the all physical laboratories, including the Natural Sources Dosimetry Laboratory, without government funding. Nevertheless, as it is shown below, this period was the most fruitful for theoretical and experimental researches, and for development of legal documents and instructional guidance documents. Over these years, more than 10 sanitary regulations and hygienic standards, and more than 20 guidance documents were developed and implemented. Doses of the population due to the natural exposure data-collecting system on the base of federal statistical observation №4-DOZ form were designed. At this period, the first Federal Target Program «Radon» and the System of radiation and hygienic passportization of organizations and territories were developed and authorized. Dr. E.M. Krisiuk was fully engaged in these activities. In these years a great number of non-nuclear companies were examined. Large-scale studies of levels of exposure of the population on specific territories were conducted. The paper examines a summary of the main results, which were obtained in the most important areas of research and practical studies in the period under review.

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

    Energy Technology Data Exchange (ETDEWEB)

    Doo Seong Hwang; Hei Min Choi; Kune Woo Lee; Jei Kwon Moon [KAERI, Daejeon (Korea, Republic of)

    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)

  9. 15th International Conference on Boron Chemistry (IMEBORON XV)

    Czech Academy of Sciences Publication Activity Database

    Grüner, Bohumír; Štíbr, Bohumil

    2015-01-01

    Roč. 87, č. 2 (2015), s. 121 ISSN 0033-4545 Institutional support: RVO:61388980 Keywords : boranes * boron * boron materials * carboranes * IMEBORON XV * medicinal chemistry Subject RIV: CA - Inorganic Chemistry

  10. Structure prediction of boron-doped graphene by machine learning

    Science.gov (United States)

    M. Dieb, Thaer; Hou, Zhufeng; Tsuda, Koji

    2018-06-01

    Heteroatom doping has endowed graphene with manifold aspects of material properties and boosted its applications. The atomic structure determination of doped graphene is vital to understand its material properties. Motivated by the recently synthesized boron-doped graphene with relatively high concentration, here we employ machine learning methods to search the most stable structures of doped boron atoms in graphene, in conjunction with the atomistic simulations. From the determined stable structures, we find that in the free-standing pristine graphene, the doped boron atoms energetically prefer to substitute for the carbon atoms at different sublattice sites and that the para configuration of boron-boron pair is dominant in the cases of high boron concentrations. The boron doping can increase the work function of graphene by 0.7 eV for a boron content higher than 3.1%.

  11. Boron: out of the sky and onto the ground

    International Nuclear Information System (INIS)

    Kuehl, D.K.

    1975-01-01

    Now an accepted, engineered material for aerospace applications, boron is taking its place on the ground. Both current production applications, prototype (development) applications, and speculative applications abound. In the leisure product market, boron epoxy or boron aluminum has been used or tried in golf clubs (in combination with graphite epoxy or to reinforce aluminum or steel), in tennis racquets, in bicycles, racing shells, skis and skipoles, bows and arrows, and others. In the industrial area, boron has been used to reduce fatigue, increase stiffness, or for its abrasive properties. Textile machinery, honing tools, and cut off wheels or saws are among the applications. In the medical field, prosthetics and orthotic braces, wheel chairs, canes, and crutches are all good applications for boron. Applications for boron in transportation, construction, and heavy industry are also possible. The volume of boron used in these applications could have a major impact on prices, making boron composite parts cost competitive with conventional materials. (U.S.)

  12. The Influence of Parameters Affecting Boron Removal by Electrocoagulation Process

    KAUST Repository

    Zeboudji, B.; Drouiche, Nadjib; Lounici, Hakim; Mameri, Nabil; Ghaffour, NorEddine

    2013-01-01

    , this process requires chemical addition and important additional investment, operation and maintenance, and energy costs. Electrocoagulation (EC) process can be used to achieve such low boron concentration. In this work, the removal of boron from aqueous

  13. Surface modification of EN-C35E steels by thermo-chemical boronizing process and its properties

    International Nuclear Information System (INIS)

    Yapar, U.; Arisoy, C.F.; Basman, G.; Yesilcubuk, S.A.; Sesen, M.K.

    2004-01-01

    Boronizing, which involves diffusion of boron atoms into steel substrate to form hard iron borides is well known diffusion coating technique. In this study, salt bath boronizing processes were performed on EN-C35E steel substrate in slurry salt bath containing borax, boric acid as boron sources and ferro-silicon as reductant. The process was performed at 850 and 950 C for 2, 4, 6 and 8 hours. Boride layers were examined by optical microscope (OM), scanning electron microscope (SEM) and X-ray diffraction (XRD). Hardness of borides formed on the steel substrate was measured by knoop indenter under load of 0.5N. Metallographic studies and XRD analysis revealed that single-type Fe 2 B layers were formed. Depending on boronizing time and temperature, it has found that the hardness of boride layer ranged from 1895-2143 HK 0.05 that is nearly 8 times higher than substrate hardness. The thickness of the layer ranged from 25 to 167 μm depending on boronizing time and temperature. (orig.)

  14. Sedimentary mercury (Hg) in the marginal seas adjacent to Chinese high-Hg emissions: Source-to-sink, mass inventory, and accumulation history.

    Science.gov (United States)

    Kim, Jihun; Lim, Dhongil; Jung, Dohyun; Kang, Jeongwon; Jung, Hoisoo; Woo, Hanjun; Jeong, Kapsik; Xu, Zhaokai

    2018-03-01

    We comprehensively investigated sedimentary Hg in Yellow and East China Seas (YECSs), which constitute potentially important depocenters for large anthropogenic Hg emissions from mainland China. A large dataset of Al-TOC-Hg concentrations led to an in-depth understanding of sedimentary Hg in the entire YECSs, including distribution and its determinants, source-to-sink, background levels, inventory in flux and budget, and accumulation history. Especially, the net atmospheric Hg flux to the sediments was estimated to be 1.3 × 10 -5  g/m 2 /yr, which corresponded reasonably well to that calculated using a box model. About 21.2 tons of atmospheric Hg (approximately 4% of the total anthropogenic atmospheric Hg emissions from China) were buried annually in the YECS basin. This result implies that most of atmospheric Hg from China is transferred to the surface of the Pacific (including the East/Japan Sea and South China Sea) by the westerlies and, consequently, can play a critical role in open-sea aquatic ecosystems. Copyright © 2018 Elsevier Ltd. All rights reserved.

  15. Explicit treatment of spectral history effects in PWR design

    International Nuclear Information System (INIS)

    Gavin, P.H.

    1995-01-01

    Spectral history effects in pressurized water reactors (PWRs) are a consequence of spatially distributed and/or time-dependent quantities such as power, moderator temperature, soluble boron concentration, control rod position, etc., defining open-quotes operating conditions.close quotes Operating conditions, global and local, affect neutron spectrum and isotopic reaction rates and thus the evolution of the fuel composition. Any effect that hardens the neutron spectrum, such as elevated temperature or high soluble boron concentration, will increase the fuel conversion ratio and result in more reactive fuel. This paper describes history effects for an 18-month equilibruim cycle of an ABB CE system 80 PWR

  16. The intergranular segregation of boron in substoichiometric Ni/sub 3/Al

    Energy Technology Data Exchange (ETDEWEB)

    Choudhury, A.

    1987-12-01

    The intermetallic compound Ni/sub 3/Al offers promise as a material for high temperature applications. In addition to its unusual property of increasing strength with temperature (until approx.700/sup 0/C), it has excellent corrosion and oxidation resistance. Microalloying the alloy with boron has been shown to be dramatically effective in improving its inherent intergranular brittleness. This improvement results from the strong tendency of boron to segregate to the grain boundaries of Ni/sub 3/Al. This research deals with the study of the segregation behavior of boron. Auger electron spectroscopy was chosen as the technique adopted to study this segregation. The strong effect of segregant level on the grain boundary strength level can be controlled by thermal history variations and by variations in the level of solute in the bulk. Cathodic hydrogen charging was shown to be a potent tool in opening up other wise cohesive boundaries for analysis. The effective binding energy of boron at the grain boundaries of Ni/sub 3/Al was calculated from experimental data; it was found to vary between 0.2 and 0.45 eV. Kinetics of segregation have been investigated; the present set of kinetic studies were shown to be inadequate to find a diffusion coefficient and that temperatures lower than those studied here need to be used. As an associated investigation, a set of elemental standards were developed for the particular scanning Auger microprobe used in this study. 141 refs., 94 figs., 26 tabs.

  17. Boron Removal in Seawater Reverse Osmosis System

    KAUST Repository

    Rahmawati, Karina

    2011-07-01

    Reverse osmosis successfully proves to remove more than 99% of solute in seawater, providing fresh water supply with satisfied quality. Due to some operational constraints, however, some trace contaminants removal, such as boron, cannot be achieved in one pass system. The stringent criterion for boron from World Health Organization (WHO) and Saudi Arabia local standard (0.5 mg/l) is hardly fulfilled by single pass sea water reverse osmosis (SWRO) plants. Some design processes have been proposed to deal with boron removal, but they are not economically efficient due to high energy and chemical consumption. The objective of this study was to study boron removal by different reverse osmosis membranes in two pH conditions, with and without antiscalant addition. Thus, it was expected to observe the possibility of operating single pass system and necessity to operate two pass system using low energy membrane. Five membrane samples were obtained from two different manufacturers. Three types of feed water pH were used, pH 8, pH 10, and pH 10 with antiscalant addition. Experiment was conducted in parallel to compare membrane performance from two manufacturers. Filtration was run with fully recycle mode for three days. Sample of permeate and feed were taken every 12 hours, and analyzed for their boron and TDS concentration. Membrane samples were also tested for their surface charge. The results showed that boron rejection increases as the feed pH increases. This was caused by dissociation of boric acid to negatively charged borate ion and more negatively charged membrane surface at elevated pH which enhance boron rejection. This study found that single pass reverse osmosis system, with and without elevating the pH, may not be possible to be applied because of two reasons. First, permeate quality in term of boron, does not fulfill WHO and local Saudi Arabia regulations. Second, severe scaling occurs due to operation in alkaline condition, since Ca and Mg concentration are

  18. Boron tolerance in NS wheat lines

    Directory of Open Access Journals (Sweden)

    Brdar Milka

    2006-01-01

    Full Text Available Boron is an essential micronutrient for higher plants. Present in excessive amounts boron becomes toxic and can limit plant growth and yield. Suppression of root growth is one of the symptoms of boron toxicity in wheat. This study was undertaken to investigate the response of 10 perspective NS lines of wheat to high concentrations of boron. Analysis of root growth was done on young plants, germinated and grown in the presence of different concentrations of boric acid (0, 50,100 and 150 mg/1. Significant differences occurred between analyzed genotypes and treatments regarding root length. Average suppression of root growth was between 11,6 and 34,2%, for line NS 252/02 are even noted 61,4% longer roots at treatments in relation to the control. Lines with mean suppression of root growth less than 20% (NS 101/02, NS 138/01, NS 53/03 and NS 73/02 may be considered as boron tolerant. Spearmans coefficients showed high level of agreement regarding rang of root length for genotypes treated with 100 and 150 mg H3BO3/l.

  19. Hot ductility behavior of boron microalloyed steels

    International Nuclear Information System (INIS)

    Lopez-Chipres, E.; Mejia, I.; Maldonado, C.; Bedolla-Jacuinde, A.; Cabrera, J.M.

    2007-01-01

    The current study analyses the influence of boron contents (between 29 and 105 ppm) on the hot ductility of boron microalloyed steels. For this purpose, hot tensile tests were carried out at different temperatures (700, 800, 900 and 1000 deg. C) at a constant true strain rate of 0.001 s -1 . In general, results revealed an improvement of the hot ductility of steels at increasing boron content. At 700, 900 and 1000 deg. C the ductility is higher than at 800 deg. C, where boron microalloyed steels exhibit a region of ductility loss (trough region). Likewise, dynamic recrystallization only occurred at 900 and 1000 deg. C. The fracture surfaces of the tested steels at temperatures giving the high temperature ductility regime show that the fracture mode is a result of ductile failure, whereas it is ductile-brittle failure in the trough region. Results are discussed in terms of dynamic recrystallization and boron segregation towards austenite grain boundaries, which may retard the formation of pro-eutectoid ferrite and increase grain boundary cohesion

  20. Technology of boron-containing polyphosphate fertilizer 'Phosphobor'

    International Nuclear Information System (INIS)

    Aldabergenov, M.K.; Balakaeva, T.G.

    1995-01-01

    A technology is developed for producing 'Phosphobor' fertilizer based on the rock phosphate weal (17-18% P 2 O 5 ) with additions of boron-magnesium compound. Boron is part of polyphosphate fertilizer in the form of polymeric compounds of phosphorus and boron. Phosphorus and boron copolymers -boratophosphates - are easily formed in the process of polyphosphate fertilizers production, since borates undergo a mutual polycondensation reaction with phosphates. 8 refs., 1 fig

  1. Determination of free carbon content in boron carbide ceramic powders

    International Nuclear Information System (INIS)

    Castro, A.R.M. de; Lima, N.B. de; Paschoal, J.O.A.

    1990-01-01

    Boron carbide is a ceramic material of technological importance due to its hardness and high chemical and thermal stabilities. Free carbon is always found as a process dependent impurity in boron carbide. The development of procedures for its detection is required because its presence leads to a degradation of the boron carbide properties. In this work, several procedures for determining free carbon content in boron carbide specimens are reported and discussed for comparison purposes. (author) [pt

  2. Monte Carlo calculations on efficiency of boron neutron capture therapy for brain cancer

    International Nuclear Information System (INIS)

    Awadalla, Galaleldin Mohamed Suliman

    2015-11-01

    The search for ways to treat cancer has led to many different treatments, including surgery, chemotherapy, and radiation therapy. Among these treatments, boron neutron capture therapy (BNCT) has shown promising results. BNCT is a radiotherapy treatment modality that has been proposed to treat brain cancer. In this technique, cancerous cells are being injected with 1 0B and irradiated by thermal neutrons to increase the probability of 1 0B (n, a)7 L i reaction to occur. This reaction can potentially deliver a high radiation dose sufficient to kill cancer cells by concentrating boron in them. The short rang of 1 0B (n, a) 7 L i reaction limits the damage to only cancerous cells without affecting healthy tissues. The effectiveness and safety of radiotherapy are dependent on the radiation dose delivered to the tumor and healthy tissues. In this thesis, after reviewing the basics and working principles of boron neutron capture therapy (BNCT), monte Carlo simulations were carried out to model a thermal neutron source suitable for BNCT and to examine the performance of proposed model when used to irradiate a sample of boron containing both 1 0B and 1 1B isotopes. MCNP5 code was used to examine the modeled neutron source through different shielding materials. The results were presented, analyzed and discussed at the end of the work. (author)

  3. In situ boron doping during heteroepitaxial growth of diamond on Ir/YSZ/Si

    Energy Technology Data Exchange (ETDEWEB)

    Sartori, Andre F.; Fischer, Martin; Gsell, Stefan; Schreck, Matthias [Universitaet Augsburg, Institut fuer Physik, 86135 Augsburg (Germany)

    2012-09-15

    In situ boron doping of heteroepitaxial diamond films grown by microwave plasma chemical vapor deposition on Ir/YSZ/Si (001) is investigated. The study comprises the analysis of the gas phase by optical emission spectroscopy (OES) and measurements of B doped films by secondary ion mass spectroscopy (SIMS), cathodoluminescence (CL), and X-ray diffraction (XRD). The OE intensity of BH species scales linearly with the concentration of the boron precursor trimethylboron (TMB) in the feed gas. Addition of CO{sub 2} as an oxygen source causes a proportional reduction of the BH signal. At a ratio C:O = 1, a reduction factor of {proportional_to}50 is obtained. It is shown for two diamond samples that the boron incorporation drops nearly identical to the BH emission intensity. We conclude that the influence of oxygen on boron incorporation is a pure gas phase effect. In contrast, CN and BH emission indicate a negligible interaction between N{sub 2} and TMB added to the feed gas. At the same time, preliminary growth rate measurements show that the boron background pressure in the chamber after growth with TMB completely cancels the growth acceleration by nitrogen up to N{sub 2} concentrations of 100 ppm which points to the dominance of surface processes. Heteroepitaxial diamond films grown on Ir at 50 mbar between 720 and 900 C contain high intrinsic stress that varies from -2.2 GPa compressive at the lowest to slightly tensile at the highest deposition temperature. The observed behavior is similar to former work at 200 mbar in which effective climb of dislocations was suggested as responsible mechanism. Addition of boron rather enhances the stress formation than causing a relaxation. The B concentration in the heteroepitaxial films is deduced by SIMS, CL, and XRD and correlated with the TMB concentration in the gas phase. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. Screening of Wheat Genotypes for Boron Efficiency in Bangladesh

    Science.gov (United States)

    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 ...

  5. The effects of boron management on soil microbial population and ...

    African Journals Online (AJOL)

    Soil microorganisms directly influence boron content of soil as maximum boron release corresponds with the highest microbial activity. The objective of this study is to determine the effects of different levels of boron fertilizer on microbial population, microbial respiration and soil enzyme activities in different soil depths in ...

  6. Oxidation of boron carbide at high temperatures

    International Nuclear Information System (INIS)

    Steinbrueck, Martin

    2005-01-01

    The oxidation kinetics of various types of boron carbides (pellets, powder) were investigated in the temperature range between 1073 and 1873 K. Oxidation rates were measured in transient and isothermal tests by means of mass spectrometric gas analysis. Oxidation of boron carbide is controlled by the formation of superficial liquid boron oxide and its loss due to the reaction with surplus steam to volatile boric acids and/or direct evaporation at temperatures above 1770 K. The overall reaction kinetics is paralinear. Linear oxidation kinetics established soon after the initiation of oxidation under the test conditions described in this report. Oxidation is strongly influenced by the thermohydraulic boundary conditions and in particular by the steam partial pressure and flow rate. On the other hand, the microstructure of the B 4 C samples has a limited influence on oxidation. Very low amounts of methane were produced in these tests

  7. The ternary system nickel-boron-silicon

    International Nuclear Information System (INIS)

    Lugscheider, E.; Reimann, H.; Knotek, O.

    1975-01-01

    The ternary system Nickel-Boron-Silicon was established at 850 0 C by means of X-ray diffraction, metallographic and micro-hardness examinations. The well known binary nickel borides and silicides resp. were confirmed. In the boron-silicon system two binary phases, SiBsub(4-x) with x approximately 0.7 and SiB 6 were found the latter in equilibrium with the β-rhombohedral boron. Confirming the two ternary silicon borides a greater homogeneity range was found for Ni 6 Si 2 B, the phase Nisub(4,6)Si 2 B published by Uraz and Rundqvist can better be described by the formula Nisub(4.29)Si 2 Bsub(1.43). In relation to further investigations we measured melting temperatures in ternary Ni-10 B-Si alloys by differential thermoanalysis. (author)

  8. Depth resolved investigations of boron implanted silicon

    Science.gov (United States)

    Sztucki, M.; Metzger, T. H.; Milita, S.; Berberich, F.; Schell, N.; Rouvière, J. L.; Patel, J.

    2003-01-01

    We have studied the depth distribution and structure of defects in boron implanted silicon (0 0 1). Silicon wafers were implanted with a boron dose of 6×10 15 ions/cm -2 at 32 keV and went through different annealing treatments. Using diffuse X-ray scattering at grazing incidence and exit angles we are able to distinguish between different kinds of defects (point defect clusters and extrinsic stacking faults on {1 1 1} planes) and to determine their depth distribution as a function of the thermal budget. Cross-section transmission electron microscopy was used to gain complementary information. In addition we have determined the strain distribution caused by the boron implantation as a function of depth from rocking curve measurements.

  9. Radiation hardening of MOS devices by boron

    International Nuclear Information System (INIS)

    Danchenko, V.

    1975-01-01

    A novel technique is disclosed for radiation hardening of MOS devices and specifically for stabilizing the gate threshold potential at room temperature of a radiation subjected MOS field-effect device of the type having a semiconductor substrate, an insulating layer of oxide on the substrate, and a gate electrode disposed on the insulating layer. In the preferred embodiment, the novel inventive technique contemplates the introduction of boron into the insulating oxide, the boron being introduced within a layer of the oxide of about 100A to 300A thickness immediately adjacent the semiconductor-insulator interface. The concentration of boron in the oxide layer is preferably maintained on the order of 10 atoms/ cm 3 . The novel technique serves to reduce and substantially annihilate radiation induced positive gate charge accumulations, which accumulations, if not eliminated, would cause shifting of the gate threshold potential of a radiation subjected MOS device, and thus render the device unstable and/or inoperative. (auth)

  10. BC-454 boron-loaded plastic scintillator

    International Nuclear Information System (INIS)

    Bellian, J.G.

    1984-01-01

    Prototype samples of plastic scintillators containing up to 10% by weight of natural boron have been produced. The maximum size scintillators made to date are 28 mm dia. x 100 mm long. Rods containing up to 2% boron are now made routinely and work is progressing on higher concentrations. The plastics are clear and emit the same blue fluorescence as other common plastic scintillators. It is expected that rods up to 3'' dia. containing 5% boron will be produced during the next few months. BC-454 is particularly useful in neutron research, materials studies, some types of neutron dosimetry, and monitoring of medium to high energy neutrons in the presence of other types radiation. It combines attractive features that enhance its usefulness to the physics community

  11. A system to deposit boron films (boronization) in the DIII-D tokamak

    International Nuclear Information System (INIS)

    Hodapp, T.R.; Jackson, G.L.; Phillips, J.; Holtrop, K.L.; Peterson, P.L.; Winters, J.

    1992-01-01

    A system has been added to the DIII-D tokamak to coat its plasma facing surfaces with a film of boron using diborane gas. The system includes special health and safety equipment for handling the diborane gas which is toxic and inflammable. The purpose f the boron film is to reduce the levels of impurity atoms in the DIII-D plasmas. Experiments following the application of the boron film in DIII-D have led to significant reductions in plasma impurity levels and the observation of a new, very high confinement regime

  12. A system to deposit boron films (boronization) in the DIII-D tokamak

    International Nuclear Information System (INIS)

    Hodapp, T.R.; Jackson, G.L.; Phillips, J.; Holtrop, K.L.; Petersen, P.I.; Winter, J.

    1991-09-01

    A system has been added to the D3-D tokamak to coat its plasma facing surfaces with a film of boron using diborane gas. The system includes special health and safety equipment for handling the diborane gas which is toxic and inflammable. The purpose of the boron film is to reduce the levels of impurity atoms in the D3-D plasmas. Experiments following the application of the boron film in D3-D have led to significant reductions in plasma impurity levels and the observation of a new, very high confinement regime. 9 refs., 1 fig

  13. Boron removal by electrocoagulation and recovery.

    Science.gov (United States)

    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. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. Boron nitride nanotubes for spintronics.

    Science.gov (United States)

    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.

  15. Boron Nitride Nanotubes for Spintronics

    Directory of Open Access Journals (Sweden)

    Kamal B. Dhungana

    2014-09-01

    Full Text Available 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.

  16. Titanium reinforced boron-polyimide composite

    Science.gov (United States)

    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.

  17. Designing your boron-charging system

    International Nuclear Information System (INIS)

    Miller, J.

    1979-01-01

    High-pressure positive-displacement pumps used in the boron-charging setups of pressurized-water (PWR) nuclear plants because of their inherently high efficiencies over a wide range of pressures and speeds are described. Hydrogen-saturated water containing 4-12% boric acid is fed to the pump from a volume-control tank under a gas blanket. Complicated piping and the pulsation difficulties associated with reciprocating pumps make hydrogen-saturated boron-charging systems a challenge to the designer. The article describes the unusual hydraulics of the systems to help assure a trouble-free design

  18. Boron-containing organic pigments from a Jurassic red alga.

    Science.gov (United States)

    Wolkenstein, Klaus; Gross, Jürgen H; Falk, Heinz

    2010-11-09

    Organic biomolecules that have retained their basic chemical structures over geological periods (molecular fossils) occur in a wide range of geological samples and provide valuable paleobiological, paleoenvironmental, and geochemical information not attainable from other sources. In rare cases, such compounds are even preserved with their specific functional groups and still occur within the organisms that produced them, providing direct information on the biochemical inventory of extinct organisms and their possible evolutionary relationships. Here we report the discovery of an exceptional group of boron-containing compounds, the borolithochromes, causing the distinct pink coloration of well-preserved specimens of the Jurassic red alga Solenopora jurassica. The borolithochromes are characterized as complicated spiroborates (boric acid esters) with two phenolic moieties as boron ligands, representing a unique class of fossil organic pigments. The chiroptical properties of the pigments unequivocally demonstrate a biogenic origin, at least of their ligands. However, although the borolithochromes originated from a fossil red alga, no analogy with hitherto known present-day red algal pigments was found. The occurrence of the borolithochromes or their possible diagenetic products in the fossil record may provide additional information on the classification and phylogeny of fossil calcareous algae.

  19. Boron carbide-carbon composites and composites for cryogenic applications

    International Nuclear Information System (INIS)

    Sheinberg, H.

    1979-01-01

    Because of its neutronic properties, high hardness, and high melting temperature, boron carbide (B 4 C) is widely used at the Los Alamos Scientific Laboratory. However because of its hardness and mode of manufacture, it is expensive to machine finish to tight dimensional specifictions. For some neutronic applications, a density considerably below the theoretical 2.52 Mg/m 3 was acceptable, and this relaxation in density specification permitted addition of carbon as a second phase to reduce machining costs. We conducted an experimental program to prepare 50.8-mm-diam by 34.8-mm-thick cylinders of B 4 C and B 4 C-C composites with concentrations of carbon varying from 5.5 to 30 volume percent. Additionally we used three forms of carbon, natural flake graphite, synthetic graphite flour, and a fine furnace black as the source of the second phase. We determined the sound velocity, compressive strength, coefficient of thermal expansion, electrical resistivity, and microstructure as functions of composition. Additionally, an enriched boron ( 10 B)-carbon composite was studied as an alternate material

  20. Model for calculating the boron concentration in PWR type reactors

    International Nuclear Information System (INIS)

    Reis Martins Junior, L.L. dos; Vanni, E.A.

    1986-01-01

    A PWR boron concentration model has been developed for use with RETRAN code. The concentration model calculates the boron mass balance in the primary circuit as the injected boron mixes and is transported through the same circuit. RETRAN control blocks are used to calculate the boron concentration in fluid volumes during steady-state and transient conditions. The boron reactivity worth is obtained from the core concentration and used in RETRAN point kinetics model. A FSAR type analysis of a Steam Line Break Accident in Angra I plant was selected to test the model and the results obtained indicate a sucessfull performance. (Author) [pt

  1. A Simulation Study for Radiation Treatment Planning Based on the Atomic Physics of the Proton-Boron Fusion Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sunmi; Yoon, Do-Kun; Shin, Han-Back; Jung, Joo-Young; Kim, Moo-Sub; Kim, Kyeong-Hyeon; Jang, Hong-Seok; Suh, Tae Suk [the Catholic University of Korea, Seoul (Korea, Republic of)

    2017-03-15

    The purpose of this research is to demonstrate, based on a Monte Carlo simulation code, the procedure of radiation treatment planning for proton-boron fusion therapy (PBFT). A discrete proton beam (60 - 120 MeV) relevant to the Bragg peak was simulated using a Monte Carlo particle extended (MCNPX, Ver. 2.6.0, National Laboratory, Los Alamos NM, USA) simulation code. After computed tomography (CT) scanning of a virtual water phantom including air cavities, the acquired CT images were converted using the simulation source code. We set the boron uptake regions (BURs) in the simulated water phantom to achieve the proton-boron fusion reaction. Proton sources irradiated the BUR, in the phantom. The acquired dose maps were overlapped with the original CT image of the phantom to analyze the dose volume histogram (DVH). We successfully confirmed amplifications of the proton doses (average: 130%) at the target regions. From the DVH result for each simulation, we acquired a relatively accurate dose map for the treatment. A simulation was conducted to characterize the dose distribution and verify the feasibility of proton boron fusion therapy (PBFT). We observed a variation in proton range and developed a tumor targeting technique for treatment that was more accurate and powerful than both conventional proton therapy and boron-neutron capture therapy.

  2. Insights into the Mechanisms Underlying Boron Homeostasis in Plants

    Directory of Open Access Journals (Sweden)

    Akira Yoshinari

    2017-11-01

    Full Text Available Boron is an essential element for plants but is toxic in excess. Therefore, plants must adapt to both limiting and excess boron conditions for normal growth. Boron transport in plants is primarily based on three transport mechanisms across the plasma membrane: passive diffusion of boric acid, facilitated diffusion of boric acid via channels, and export of borate anion via transporters. Under boron -limiting conditions, boric acid channels and borate exporters function in the uptake and translocation of boron to support growth of various plant species. In Arabidopsis thaliana, NIP5;1 and BOR1 are located in the plasma membrane and polarized toward soil and stele, respectively, in various root cells, for efficient transport of boron from the soil to the stele. Importantly, sufficient levels of boron induce downregulation of NIP5;1 and BOR1 through mRNA degradation and proteolysis through endocytosis, respectively. In addition, borate exporters, such as Arabidopsis BOR4 and barley Bot1, function in boron exclusion from tissues and cells under conditions of excess boron. Thus, plants actively regulate intracellular localization and abundance of transport proteins to maintain boron homeostasis. In this review, the physiological roles and regulatory mechanisms of intracellular localization and abundance of boron transport proteins are discussed.

  3. A colorimetric determination of boron in biological sample for boron neutron capture therapy (BNCT)

    International Nuclear Information System (INIS)

    Camillo, M.A.P.; Tomac Junior, U.

    1990-01-01

    The boron neutron capture therapy (BNCT) has shown better prognosis in the treatment of glyemas and gluoblastomas grade III and IV than other therapies. During the treatment the levels of Na 2 10 B 12 H 11 SH must be known in several compartiments of the organism and with this purpose the method of colorimetric determination of boron using curcumine was established. This method is simple, reprodutible and adequate sensitivity for this control. (author) [pt

  4. A colorimetric determination of boron in biological sample for boron neutron capture therapy

    International Nuclear Information System (INIS)

    Camilo, M.A.P.; Tomac Junior, U.

    1989-01-01

    The boron neutron capture therapy (BNCT) has shown better prognosis in the treatment of gliomas and glioblastomas grade III and IV than other therapies. During the treatment of levels of Na 2 10 B 12 H 11 S H must be known in several compartments of the organism and with this purpose the method of colorimetric determination of boron using curcumin was established. This method is simples, reproducible and has adequate sensitivity for this control. (author). 7 refs, 3 figs, 1 tab

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

    Energy Technology Data Exchange (ETDEWEB)

    Bortolussi, S., E-mail: silva.bortolussi@pv.infn.i [Department of Nuclear and Theoretical Physics, University of Pavia, via Bassi 6, 27100 Pavia (Italy); National Institute of Nuclear Physics (INFN), Section of Pavia, via Bassi 6, 27100 Pavia (Italy); Bakeine, J.G. [Department of Nuclear and Theoretical Physics, University of Pavia, via Bassi 6, 27100 Pavia (Italy); Ballarini, F. [Department of Nuclear and Theoretical Physics, University of Pavia, via Bassi 6, 27100 Pavia (Italy); National Institute of Nuclear Physics (INFN), Section of Pavia, via Bassi 6, 27100 Pavia (Italy); Bruschi, P. [Department of Nuclear and Theoretical Physics, University of Pavia, via Bassi 6, 27100 Pavia (Italy); Gadan, M.A. [Department of Nuclear and Theoretical Physics, University of Pavia, via Bassi 6, 27100 Pavia (Italy); Comision Nacional de Energia Atomica, Buenos Aires (Argentina); Protti, N.; Stella, S. [Department of Nuclear and Theoretical Physics, University of Pavia, via Bassi 6, 27100 Pavia (Italy); National Institute of Nuclear Physics (INFN), Section of Pavia, via Bassi 6, 27100 Pavia (Italy); Clerici, A.; Ferrari, C.; Cansolino, L.; Zonta, C.; Zonta, A. [Department of Surgery, University of Pavia, via Ferrata 27100 Pavia (Italy); Nano, R. [Department of Animal Biology, University of Pavia, via Ferrata 27100 Pavia (Italy); Altieri, S. [Department of Nuclear and Theoretical Physics, University of Pavia, via Bassi 6, 27100 Pavia (Italy); National Institute of Nuclear Physics (INFN), Section of Pavia, via Bassi 6, 27100 Pavia (Italy)

    2011-02-15

    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 {alpha}-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.

  6. Nuclear magnetic resonance spectroscopy of boron compounds containing two-, three- and four-coordinate boron

    International Nuclear Information System (INIS)

    Wrackmeyer, B.

    1988-01-01

    The influence of boron chemistry on various areas of research in inorganic, organic and theoretical chemistry is well documented. In fact, many models presently employed to describe chemical bonding in general can be traced to attempts to understand bonding in boranes. The confirmation of many theoretical predictions in boron chemistry relies on direct and indirect structural information provided by various physical methods that - fortunately - became available almost at the same rate as that with which the interest in boron compounds was growing. Clearly, there has always been a strong link between the interest in synthesis and the application of physical methods. As in many other areas of chemistry, developments in boron chemistry have been greatly accelerated by NMR. 11 B NMR has been at the center of interest from the beginning, accompanied by routine 1 H NMR measurements, and occasional 14 N, 19 F and 31 P NMR work. In the last 12 years, we have seen an increasing number of 13 C NMR studies of boron compounds. The availability of multinuclear facilities for PFT NMR spectrometers stimulates the measurement of the NMR spectra of other nuclei, like 29 Si, 119 Sn or other metals, in order to obtain additional information. This paper is intended to serve several purposes: to update previous reviews on 11 B NMR of boron compounds, to demonstrate some applications of multinuclear NMR to boron chemistry; to attempt to incorporate new NMR parameters into the known data set; and to summarize the experimental facts required for obtaining the maximum information from NMR studies on boron compounds

  7. Experimental tolerance to boron of the plant species Nicotiana glauca, Jacaranda mimosifolia, Tecoma stans, Medicago sativa y Spinacea oleracea in Argentina

    International Nuclear Information System (INIS)

    Viana, Marta L. de; Albarracin Franco, Silvia

    2008-01-01

    The activity of the borate deposits industries constitutes a point source and diffuse pollution of air, soil and water. Therefore, the study and experimentation on possible ways to offset this impact is a priority. A relatively new technique to decontaminate soils is phytoremediation, which uses plants and associated microorganisms. The first step is to identify tolerant plant species, which is the focus of this work. An experiment was conducted in the laboratory to evaluate the germination, survival and growth of different species in different concentrations of boron. At the beginning and end of the experiment was determined concentration of boron in the substrate for each treatment and for substrates with and without vegetation. Significant differences due to treatment, the species and species-treatment interaction. M. sativa, N. glauca and J. mimosifolia were the species most tolerant to boron. The other species showed a decrease in all variables-response function of the concentration of the contaminant. All had low survival in the highest concentration. The decrease of boron was highest in the treatment of 30 ppm of boron with M. sativa and the lowest was recorded in the treatment of 20 ppm of boron with J. mimosifolia and 30 ppm of boron with T. stans and S. oleracea. It is concluded that N. glauca, M. sativa and J. mimosifolia could be considered as promising remediation. (author) [es

  8. Use of B{sub 2}O{sub 3} films grown by plasma-assisted atomic layer deposition for shallow boron doping in silicon

    Energy Technology Data Exchange (ETDEWEB)

    Kalkofen, Bodo, E-mail: bodo.kalkofen@ovgu.de; Amusan, Akinwumi A.; Bukhari, Muhammad S. K.; Burte, Edmund P. [Institute of Micro and Sensor Systems, Otto-von-Guericke University, Universitätsplatz 2, 39106 Magdeburg (Germany); Garke, Bernd [Institute for Experimental Physics, Otto-von-Guericke University, Universitätsplatz 2, 39106 Magdeburg (Germany); Lisker, Marco [IHP, Im Technologiepark 25, 15236 Frankfurt (Oder) (Germany); Gargouri, Hassan [SENTECH Instruments GmbH, Schwarzschildstraße 2, 12489 Berlin (Germany)

    2015-05-15

    Plasma-assisted atomic layer deposition (PALD) was carried for growing thin boron oxide films onto silicon aiming at the formation of dopant sources for shallow boron doping of silicon by rapid thermal annealing (RTA). A remote capacitively coupled plasma source powered by GaN microwave oscillators was used for generating oxygen plasma in the PALD process with tris(dimethylamido)borane as boron containing precursor. ALD type growth was obtained; growth per cycle was highest with 0.13 nm at room temperature and decreased with higher temperature. The as-deposited films were highly unstable in ambient air and could be protected by capping with in-situ PALD grown antimony oxide films. After 16 weeks of storage in air, degradation of the film stack was observed in an electron microscope. The instability of the boron oxide, caused by moisture uptake, suggests the application of this film for testing moisture barrier properties of capping materials particularly for those grown by ALD. Boron doping of silicon was demonstrated using the uncapped PALD B{sub 2}O{sub 3} films for RTA processes without exposing them to air. The boron concentration in the silicon could be varied depending on the source layer thickness for very thin films, which favors the application of ALD for semiconductor doping processes.

  9. ICP-MS determination of boron: method optimization during preparation of graphite reference material for boron

    International Nuclear Information System (INIS)

    Granthali, S.K.; Shailaja, P.P.; Mainsha, V.; Venkatesh, K.; Kallola, K.S.; Sanjukta, A.K.

    2017-01-01

    Graphite finds widespread use in nuclear reactors as moderator, reflector, and fuel fabricating components because of its thermal stability and integrity. The manufacturing process consists of various mixing, moulding and baking operations followed by heat-treatment between 2500 °C and 3000 °C. The high temperature treatment is required to drive the amorphous carbon-to-graphite phase transformation. Since synthetic graphite is processed at high temperature, impurity concentrations in the precursor carbon get significantly reduced due to volatilization. However boron may might partly gets converted into boron carbide at high temperatures in the carbon environment of graphite and remains stable (B_4C: boiling point 3500 °C) in the matrix. Literature survey reveals the use of various methods for determination of boron. Previously we have developed a method for determination of boron in graphite electrodes using inductively coupled plasma mass spectrometry (ICP-MS). The method involves removal of graphite matrix by ignition of the sample at 800°C in presence of saturated barium hydroxide solution to prevent the loss of boron. Here we are reporting a modification in the method by using calcium carbonate in place of barium hydroxide and using beryllium (Be) as an internal standard, which resulted in a better precession. The method was validated by spike recovery experiments as well as using another technique viz. Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The modified method was applied in evaluation of boron concentration in the graphite reference material prepared

  10. Boron exposure through drinking water during pregnancy and birth size.

    Science.gov (United States)

    Igra, Annachiara Malin; Harari, Florencia; Lu, Ying; Casimiro, Esperanza; Vahter, Marie

    2016-10-01

    Boron is a metalloid found at highly varying concentrations in soil and water. Experimental data indicate that boron is a developmental toxicant, but the few human toxicity data available concern mostly male reproduction. To evaluate potential effects of boron exposure through drinking water on pregnancy outcomes. In a mother-child cohort in northern Argentina (n=194), 1-3 samples of serum, whole blood and urine were collected per woman during pregnancy and analyzed for boron and other elements to which exposure occurred, using inductively coupled plasma mass spectrometry. Infant weight, length and head circumference were measured at birth. Drinking water boron ranged 377-10,929μg/L. The serum boron concentrations during pregnancy ranged 0.73-605μg/L (median 133μg/L) and correlated strongly with whole-blood and urinary boron, and, to a lesser extent, with water boron. In multivariable-adjusted linear spline regression analysis (non-linear association), we found that serum boron concentrations above 80μg/L were inversely associated with birth length (B-0.69cm, 95% CI -1.4; -0.024, p=0.043, per 100μg/L increase in serum boron). The impact of boron appeared stronger when we restricted the exposure to the third trimester, when the serum boron concentrations were the highest (0.73-447μg/L). An increase in serum boron of 100μg/L in the third trimester corresponded to 0.9cm shorter and 120g lighter newborns (p=0.001 and 0.021, respectively). Considering that elevated boron concentrations in drinking water are common in many areas of the world, although more screening is warranted, our novel findings warrant additional research on early-life exposure in other populations. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  11. Boron neutron capture therapy of malignant brain tumors at the Brookhaven Medical Research Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Joel, D.D.; Coderre, J.A.; Chanana, A.D. [Brookhaven National Lab., Upton, NY (United States). Medical Dept.

    1996-12-31

    Boron neutron capture therapy (BNCT) is a bimodal form of radiation therapy for cancer. The first component of this treatment is the preferential localization of the stable isotope {sup 10}B in tumor cells by targeting with boronated compounds. The tumor and surrounding tissue is then irradiated with a neutron beam resulting in thermal neutron/{sup 10}B reactions ({sup 10}B(n,{alpha}){sup 7}Li) resulting in the production of localized high LET radiation from alpha and {sup 7}Li particles. These products of the neutron capture reaction are very damaging to cells, but of short range so that the majority of the ionizing energy released is microscopically confined to the vicinity of the boron-containing compound. In principal it should be possible with BNCT to selectively destroy small nests or even single cancer cells located within normal tissue. It follows that the major improvements in this form of radiation therapy are going to come largely from the development of boron compounds with greater tumor selectivity, although there will certainly be advances made in neutron beam quality as well as the possible development of alternative sources of neutron beams, particularly accelerator-based epithermal neutron beams.

  12. Optimization of the indirect at neutron activation technique for the determination of boron in aqueous solutions

    International Nuclear Information System (INIS)

    Luz, L.C.Q.P. da.

    1984-01-01

    The purpose of this work was the development of an instrumental method for the optimization of the indirect neutron activation analysis of boron in aqueous solutions. The optimization took into account the analytical parameters under laboratory conditions: activation carried out with a 241 Am/Be neutron source and detection of the activity induced in vanadium with two NaI(Tl) gamma spectrometers. A calibration curve was thus obtained for a concentration range of 0 to 5000 ppm B. Later on, experimental models were built in order to study the feasibility of automation. The analysis of boron was finally performed, under the previously established conditions, with an automated system comprising the operations of transport, irradiation and counting. An improvement in the quality of the analysis was observed, with boron concentrations as low as 5 ppm being determined with a precision level better than 0.4%. The experimental model features all basic design elements for an automated device for the analysis of boron in agueous solutions wherever this is required, as in the operation of nuclear reactors. (Author) [pt

  13. Boron neutron capture therapy of malignant brain tumors at the Brookhaven Medical Research Reactor

    International Nuclear Information System (INIS)

    Joel, D.D.; Coderre, J.A.; Chanana, A.D.

    1996-01-01

    Boron neutron capture therapy (BNCT) is a bimodal form of radiation therapy for cancer. The first component of this treatment is the preferential localization of the stable isotope 10 B in tumor cells by targeting with boronated compounds. The tumor and surrounding tissue is then irradiated with a neutron beam resulting in thermal neutron/ 10 B reactions ( 10 B(n,α) 7 Li) resulting in the production of localized high LET radiation from alpha and 7 Li particles. These products of the neutron capture reaction are very damaging to cells, but of short range so that the majority of the ionizing energy released is microscopically confined to the vicinity of the boron-containing compound. In principal it should be possible with BNCT to selectively destroy small nests or even single cancer cells located within normal tissue. It follows that the major improvements in this form of radiation therapy are going to come largely from the development of boron compounds with greater tumor selectivity, although there will certainly be advances made in neutron beam quality as well as the possible development of alternative sources of neutron beams, particularly accelerator-based epithermal neutron beams

  14. Boron nitride nanosheets reinforced glass matrix composites

    Czech Academy of Sciences Publication Activity Database

    Saggar, Richa; Porwal, H.; Tatarko, P.; Dlouhý, Ivo; Reece, M. J.

    2015-01-01

    Roč. 114, SEP (2015), S26-S32 ISSN 1743-6753 R&D Projects: GA MŠk(CZ) 7AMB14SK155 EU Projects: European Commission(XE) 264526 Institutional support: RVO:68081723 Keywords : Boron nitride nanosheets * Borosilicate glass * Mechanical properties Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 1.162, year: 2015

  15. Boron-doped manganese dioxide for supercapacitors.

    Science.gov (United States)

    Chi, Hong Zhong; Li, Yuwei; Xin, Yingxu; Qin, Haiying

    2014-11-11

    The addition of boron as a dopant during the reaction between carbon fiber and permanganate led to significant enhancement of the growth-rate and formation of the porous framework. The doped MnO2 was superior to the pristine sample as electrode materials for supercapacitors in terms of the specific capacitance and rate capability.

  16. Intrinsic ferromagnetism in hexagonal boron nitride nanosheets

    Energy Technology Data Exchange (ETDEWEB)

    Si, M. S.; Gao, Daqiang, E-mail: gaodq@lzu.edu.cn, E-mail: xueds@lzu.edu.cn; Yang, Dezheng; Peng, Yong; Zhang, Z. Y.; Xue, Desheng, E-mail: gaodq@lzu.edu.cn, E-mail: xueds@lzu.edu.cn [Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou 730000 (China); Liu, Yushen [Jiangsu Laboratory of Advanced Functional Materials and College of Physics and Engineering, Changshu Institute of Technology, Changshu 215500 (China); Deng, Xiaohui [Department of Physics and Electronic Information Science, Hengyang Normal University, Hengyang 421008 (China); Zhang, G. P. [Department of Physics, Indiana State University, Terre Haute, Indiana 47809 (United States)

    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.

  17. Anomalous Seebeck coefficient in boron carbides

    International Nuclear Information System (INIS)

    Aselage, T.L.; Emin, D.; Wood, C.; Mackinnon, I.D.R.; Howard, I.A.

    1987-01-01

    Boron carbides exhibit an anomalously large Seebeck coefficient with a temperature coefficient that is characteristic of polaronic hopping between inequivalent sites. The inequivalence in the sites is associated with disorder in the solid. The temperature dependence of the Seebeck coefficient for materials prepared by different techniques provides insight into the nature of the disorder

  18. NEW ADVANCES IN BORON SOIL CHEMISTRY - Paper

    Science.gov (United States)

    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. NEW ADVANCES IN BORON SOIL CHEMISTRY

    Science.gov (United States)

    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. ...

  20. New insight into pecan boron nutrition

    Science.gov (United States)

    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...

  1. Joining of boron carbide using nickel interlayer

    International Nuclear Information System (INIS)

    Vosughi, A.; Hadian, A. M.

    2008-01-01

    Carbide ceramics such as boron carbide due to their unique properties such as low density, high refractoriness, and high strength to weight ratio have many applications in different industries. This study focuses on direct bonding of boron carbide for high temperature applications using nickel interlayer. The process variables such as bonding time, temperature, and pressure have been investigated. The microstructure of the joint area was studied using electron scanning microscope technique. At all the bonding temperatures ranging from 1150 to 1300 d eg C a reaction layer formed across the ceramic/metal interface. The thickness of the reaction layer increased by increasing temperature. The strength of the bonded samples was measured using shear testing method. The highest strength value obtained was about 100 MPa and belonged to the samples bonded at 1250 for 75 min bonding time. The strength of the joints decreased by increasing the bonding temperature above 1250 d eg C . The results of this study showed that direct bonding technique along with nickel interlayer can be successfully utilized for bonding boron carbide ceramic to itself. This method may be used for bonding boron carbide to metals as well.

  2. Influence of pollution of boron chlorinity ratio

    Digital Repository Service at National Institute of Oceanography (India)

    Narvekar, P.V.; Zingde, M.D.

    Presence of boron in domestic wastewater has resulted in high B/CI ratio at some locations in the coastal water around Bombay. A widest range (0.215-0.281) of B/CI was observed at a location with high influence of wastewater release. The mean B...

  3. Bandgap engineered graphene and hexagonal boron nitride

    Indian Academy of Sciences (India)

    In this article a double-barrier resonant tunnelling diode (DBRTD) has been modelled by taking advantage of single-layer hexagonal lattice of graphene and hexagonal boron nitride (h-BN). The DBRTD performance and operation are explored by means of a self-consistent solution inside the non-equilibrium Green's ...

  4. Reaction of boron carbide with molybdenum disilicide

    International Nuclear Information System (INIS)

    Novikov, A.V.; Melekhin, V.F.; Pegov, V.S.

    1989-01-01

    The investigation results of interaction in the B 4 C-MoSi 2 system during sintering in vacuum are presented. Sintering of boron carbide with molybdenum disilicide is shown to lead to the formation of MoB 2 , SiC, Mo 5 Si 3 compounds, the presence of carbon-containing covering plays an important role in sintering

  5. Crystal structure of isomeric boron difluoride acetylnaphtholates

    International Nuclear Information System (INIS)

    Bukvetskij, B.V.; Fedorenko, E.V.; Mirochnik, A.G.; Karasev, V.E.

    2006-01-01

    Crystal structures of luminescent isomeric acetylnaphtholates of boron difluoride are investigated. Full X-ray structural analysis is done at 293 K. Coordinated of atoms, bond angles, bond lengths, interatomic distances are determined. Results of comparative evaluations of the isomers are represented [ru

  6. Radiobiology of boron neutron capture therapy

    International Nuclear Information System (INIS)

    Bond, V.P.

    1986-01-01

    The author addresses the question of single session versus protracted therapy in the application of boron neutron therapy to tumors. As background he discusses the reasoning behind the current use of fractionated therapy with conventional low-LET radiations and difference which may obtain for neutron therapy. Several aspects of dose rates and dose levels are then addressed

  7. BCM6: New Generation of Boron Meter

    International Nuclear Information System (INIS)

    Pirat, P.

    2010-01-01

    Full text of publication follows: Rolls-Royce has developed a new generation of boron meter, based on more than 30 years of experience. The Rolls-Royce BCM6 boron meter provides Nuclear Power Plant (NPP) operators with the boron concentration of the primary circuit. The meter provides continuous and safe measurements with no manual sampling and no human contact. In this paper, technical features, advantages and customer benefits of the use of the new generation of Rolls-Royce BCM6 boron meter will be detailed. Values and associated alarms are provides over different media: 4-20 mA outputs, relays, displays in the main control room and in the chemical lab, and digital links. A special alarm avoids unexpected homogeneous dilution of the primary circuit, which is a critical operational parameter. The Rolls-Royce BCM6 boron meter is fully configurable over a set of parameters allowing adaptation to customer needs. It has a differential capability, thus eliminating neutronic noise and keeping measurements accurate, even in the case of fuel clad rupture. Measurements are accurate, reliable, and have a quick response time. Equipment meets state-of-the-art qualification requests. Designed in 2008, the BCM6 boron meter is the newest equipment of Rolls-Royce boron meters product line. It has been chosen to equip the French EPR NPP and complies with the state-of-the-art of the technology. Rolls-Royce has more than 30 years of experience in Instrumentation and Controls with more than 75 NPP units operating worldwide. All of this experience return has been put in this new generation of equipment to provide the customer with the best operation. About Rolls-Royce Rolls-Royce is a global business providing integrated power systems for use on land, at sea and in the air. The Group has a balanced business portfolio with leading market positions. Rolls-Royce has a broad range of civil nuclear expertise, including work related to licensing and safety reviews, engineering design

  8. Reproductive toxicity parameters and biological monitoring in occupationally and environmentally boron-exposed persons in Bandirma, Turkey.

    Science.gov (United States)

    Duydu, Yalçın; Başaran, Nurşen; Üstündağ, Aylin; Aydin, Sevtap; Ündeğer, Ülkü; Ataman, Osman Yavuz; Aydos, Kaan; Düker, Yalçın; Ickstadt, Katja; Waltrup, Britta Schulze; Golka, Klaus; Bolt, Hermann M

    2011-06-01

    Boric acid and sodium borates have been considered as being "toxic to reproduction and development", following results of animal studies with high doses. Experimentally, a NOAEL (no observed adverse effect level) of 17.5 mg B/kg-bw/day has been identified for the (male) reproductive effects of boron in a multigeneration study of rats, and a NOAEL for the developmental effects in rats was identified at 9.6 mg B/kg-bw/day. These values are being taken as the basis of current EU safety assessments. The present study was conducted to investigate the reproductive effects of boron exposure in workers employed in boric acid production plant in Bandirma, Turkey. In order to characterize the external and internal boron exposures, boron was determined in biological samples (blood, urine, semen), in workplace air, in food, and in water sources. Unfavorable effects of boron exposure on the reproductive toxicity indicators (concentration, motility, morphology of the sperm cells and blood levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and total testosterone) were not observed. The mean calculated daily boron exposure (DBE) of the highly exposed group was 14.45 ± 6.57 (3.32-35.62) mg/day. These human exposures represent worst-case exposure conditions to boric acid/borates in Turkey. These exposure levels are considerably lower than exposures, which have previously led to reproductive effects in experimental animals. In conclusion, this means that dose levels of boron associated with developmental and reproductive toxic effects in animals are by far not reachable for humans under conditions of normal handling and use.

  9. The certification of boron in primary ingot aluminium. BCR No.25

    International Nuclear Information System (INIS)

    Vandecasteele, C.; Colinet, E.

    1984-01-01

    This report sets out the experimental procedures used for the certification of boron in primary ingot aluminium, which has already been certified for carbon and oxygen. Samples were analysed by seven different laboratories using the following methods: spectrophotometry, ICP-emission spectrometry, isotope dilution mass spectrometry, spark source mass spectrometry and charged particle activation analysis. The analytical methods and the statistical approach to analyse the data are described

  10. Fluorescent converter and neutron absorber being made of boron nitride

    International Nuclear Information System (INIS)

    Matsumoto, G.; Teramura, M.; Sato, J.; Maeda, M.

    1983-01-01

    To improve the sensitivity of fluorescent converter is essential to the neutron radiography (NRG) which utilizes portable, not so strong, neutron sources. The fluorescent converter made of boron nitride (BN) is fabricated and tested. The sensitivity is about 1/20 of the NE426, but the homogeneity may be better. If 10 BN is utilized, the sensitivity will be five times as much as that of natural BN. Using the neutron beam of the Kyoto University Research Reactor, the flux of which is about 10 6 n/cm 2 sec, a good neutron television image was gained by X-ray television camera. As a bi-product of this converter, a flexible absorber was fabricated. (Auth.)

  11. PREFACE: The 16th International Symposium on Boron, Borides and Related Materials (ISBB 2008)

    Science.gov (United States)

    Tanaka, Takaho

    2009-07-01

    This volume of Journal of Physics: Conference Series contains invited and contributed peer-reviewed papers that were presented at the 16th International Symposium on Boron, Borides and Related Materials (ISBB 2008), which was held on 7-12 September 2008, at Kunibiki Messe, Matsue, Japan. This triennial symposium has a half-century long history starting from the 1st meeting in 1959 at Asbury Park, New Jersey. We were very pleased to organize ISBB 2008, which gathered chemists, physicists, materials scientists as well as diamond and high-pressure researchers. This meeting had a strong background in the boron-related Japanese research history, which includes the discovery of superconductivity in MgB2 and development of Nd-Fe-B hard magnets and of YB66 soft X-ray monochromator. The scope of ISBB 2008 spans both basic and applied interdisciplinary research that is centered on boron, borides and related materials, and the collection of articles defines the state of the art in research on these materials. The topics are centered on: 1. Preparation of new materials (single crystals, thin films, nanostructures, ceramics, etc) under normal or extreme conditions. 2. Crystal structure and chemical bonding (new crystal structures, nonstoichiometry, defects, clusters, quantum-chemical calculations). 3. Physical and chemical properties (band structure, phonon spectra, superconductivity; optical, electrical, magnetic, emissive, mechanical properties; phase diagrams, thermodynamics, catalytic activity, etc) in a wide range of temperatures and pressures. 4. Applications and prospects (thermoelectric converters, composites, ceramics, coatings, etc) There were a few discoveries of new materials, such as nanomaterials, and developments in applications. Many contributions were related to 4f heavy Fermion systems of rare-earth borides. Exotic mechanisms of magnetism and Kondo effects have been discussed, which may indicate another direction of development of boride. Two special sessions

  12. Ground-water pollution determined by boron isotope systematics

    International Nuclear Information System (INIS)

    Vengosh, A.; Kolodny, Y.; Spivack, A.J.

    1998-01-01

    Boron isotopic systematics as related to ground-water pollution is reviewed. We report isotopic results of contaminated ground water from the coastal aquifers of the Mediterranean in Israel, Cornia River in north-western Italy, and Salinas Valley, California. In addition, the B isotopic composition of synthetic B compounds used for detergents and fertilizers was investigated. Isotopic analyses were carried out by negative thermal ionization mass spectrometry. The investigated ground water revealed different contamination sources; underlying saline water of a marine origin in saline plumes in the Mediterranean coastal aquifer of Israel (δ 11 B=31.7 per mille to 49.9 per mille, B/Cl ratio ∼1.5x10 -3 ), mixing of fresh and sea water (25 per mille to 38 per mille, B/Cl∼7x10 -3 ) in saline water associated with salt-water intrusion to Salinas Valley, California, and a hydrothermal contribution (high B/Cl of ∼0.03, δ 11 B=2.4 per mille to 9.3 per mille) in ground water from Cornia River, Italy. The δ 11 B values of synthetic Na-borate products (-0.4 per mille to 7.5 per mille) overlap with those of natural Na-borate minerals (-0.9 per mille to 10.2 per mille). In contrast, the δ 11 B values of synthetic Ca-borate and Na/Ca borate products are significantly lower (-15 per mille to -12.1 per mille) and overlap with those of the natural Ca-borate minerals. We suggest that the original isotopic signature of the natural borate minerals is not modified during the manufacturing process of the synthetic products, and it is controlled by the crystal chemistry of borate minerals. The B concentrations in pristine ground-waters are generally low ( 11 B=39 per mille), salt-water intrusion and marine-derived brines (40 per mille to 60 per mille) are sharply different from hydrothermal fluids (δ 11 B=10 per mille to 10 per mille) and anthropogenic sources (sewage effluent: δ 11 B=0 per mille to 10 per mille; boron-fertilizer: δ 11 B=-15 per mille to 7 per mille). some

  13. Raman spectroscopy of boron-doped single-layer graphene.

    Science.gov (United States)

    Kim, Yoong Ahm; Fujisawa, Kazunori; Muramatsu, Hiroyuki; Hayashi, Takuya; Endo, Morinobu; Fujimori, Toshihiko; Kaneko, Katsumi; Terrones, Mauricio; Behrends, Jan; Eckmann, Axel; Casiraghi, Cinzia; Novoselov, Kostya S; Saito, Riichiro; Dresselhaus, Mildred S

    2012-07-24

    The introduction of foreign atoms, such as nitrogen, into the hexagonal network of an sp(2)-hybridized carbon atom monolayer has been demonstrated and constitutes an effective tool for tailoring the intrinsic properties of graphene. Here, we report that boron atoms can be efficiently substituted for carbon in graphene. Single-layer graphene substitutionally doped with boron was prepared by the mechanical exfoliation of boron-doped graphite. X-ray photoelectron spectroscopy demonstrated that the amount of substitutional boron in graphite was ~0.22 atom %. Raman spectroscopy demonstrated that the boron atoms were spaced 4.76 nm apart in single-layer graphene. The 7-fold higher intensity of the D-band when compared to the G-band was explained by the elastically scattered photoexcited electrons by boron atoms before emitting a phonon. The frequency of the G-band in single-layer substitutionally boron-doped graphene was unchanged, which could be explained by the p-type boron doping (stiffening) counteracting the tensile strain effect of the larger carbon-boron bond length (softening). Boron-doped graphene appears to be a useful tool for engineering the physical and chemical properties of graphene.

  14. Laser-induced photochemical enrichment of boron isotopes

    International Nuclear Information System (INIS)

    Freund, S.M.; Ritter, J.J.

    1976-01-01

    A boron trichloride starting material containing both boron-10 isotopes and boron-11 isotopes is selectively enriched in one or the other of these isotopes by a laser-induced photochemical method involving the reaction of laser-excited boron trichloride with either H 2 S or D 2 S. The method is carried out by subjecting a low pressure gaseous mixture of boron trichloride starting material and the sulfide to infrared radiation from a carbon dioxide TE laser. The wave length of the radiation is selected so as to selectively excite one or the other of boron-10 BCl 3 molecules or boron-11 BCl 3 molecules, thereby making them preferentially more reactive with the sulfide. The laser-induced reaction produces both a boron-containing solid phase reaction product and a gaseous phase containing mostly unreacted BCl 3 and small amounts of sulfhydroboranes. Pure boron trichloride selectively enriched in one of the isotopes is recovered as the primary product of the method from the gaseous phase by a multi-step recovery procedure. Pure boron trichloride enriched in the other isotope is recovered as a secondary product of the method by the subsequent chlorination of the solid phase reaction product followed by separation of BCl 3 from the mixture of gaseous products resulting from the chlorination

  15. Higher boron rejection with a new TFC forward osmosis membrane

    KAUST Repository

    Valladares Linares, Rodrigo; Li, Zhenyu; Sarp, Sarper; Park, Y. G.; Amy, Gary L.; Vrouwenvelder, Johannes S.

    2014-01-01

    Due to the stringent limits for boron in drinking and irrigation water, water treatment facilities have to incur additional treatment to remove boron down to a safe concentration. Forward osmosis (FO) is a membrane technology that may reduce the energy required to remove boron present in seawater. In direct FO desalination hybrid systems, fresh water is recovered from seawater using a recoverable draw solution, FO membranes are expected to show high boron rejection. This study focuses on determining the boron rejection capabilities of a new generation thin-film composite (TFC) FO membrane compared to a first generation cellulose triacetate (CTA) FO membrane. The effects of water permeate flux, membrane structure, draw solute charge, and reverse solute flux on boron rejection were determined. For TFC and CTA FO membranes, experiments showed that when similar operating conditions are applied (e.g. membrane type and draw solute type) boron rejection decreases with increase in permeate flux. Reverse draw solute flux and membrane fouling have no significant impact on boron rejection. Compared to the first generation CTA FO membrane operated at the same conditions, the TFC FO membrane showed a 40% higher boron rejection capability and a 20% higher water flux. This demonstrates the potential for boron removal for new generation TFC FO membranes. © 2014 © 2014 Balaban Desalination Publications. All rights reserved.

  16. Higher boron rejection with a new TFC forward osmosis membrane

    KAUST Repository

    Valladares Linares, Rodrigo

    2014-07-17

    Due to the stringent limits for boron in drinking and irrigation water, water treatment facilities have to incur additional treatment to remove boron down to a safe concentration. Forward osmosis (FO) is a membrane technology that may reduce the energy required to remove boron present in seawater. In direct FO desalination hybrid systems, fresh water is recovered from seawater using a recoverable draw solution, FO membranes are expected to show high boron rejection. This study focuses on determining the boron rejection capabilities of a new generation thin-film composite (TFC) FO membrane compared to a first generation cellulose triacetate (CTA) FO membrane. The effects of water permeate flux, membrane structure, draw solute charge, and reverse solute flux on boron rejection were determined. For TFC and CTA FO membranes, experiments showed that when similar operating conditions are applied (e.g. membrane type and draw solute type) boron rejection decreases with increase in permeate flux. Reverse draw solute flux and membrane fouling have no significant impact on boron rejection. Compared to the first generation CTA FO membrane operated at the same conditions, the TFC FO membrane showed a 40% higher boron rejection capability and a 20% higher water flux. This demonstrates the potential for boron removal for new generation TFC FO membranes. © 2014 © 2014 Balaban Desalination Publications. All rights reserved.

  17. Qualitative dose response of the normal canine head to epithermal neutron irradiation with and without boron capture

    International Nuclear Information System (INIS)

    DeHaan, C.E.; Gavin, P.R.; Kraft, S.L.; Wheeler, F.J.; Atkinson, C.A.

    1992-01-01

    Boron Neutron Capture Therapy is being re-evaluated for the treatment of intracranial tumors. Prior to human clinical trials, determination of normal tissue tolerance is critical. Dogs were chosen as a large animal model for the following reasons. Dogs can be evaluated with advanced imaging, diagnostic and therapeutic modalities. Dogs are amenable to detailed neurologic examination and subtle behavioral changes are easily detected. Specifically, Labrador retrievers were chosen for their large body and head size. The dogs received varying doses of epithermal neutron irradiation and boron neutron capture irradiation using an epithermal neutron source. The dogs were closely monitored for up to one year post irradiation

  18. Mesozoic–Cenozoic Climate and Neotectonic Events as Factors in Reconstructing the Thermal History of the Source-Rock Bazhenov Formation, Arctic Region, West Siberia, by the Example of the Yamal Peninsula

    Science.gov (United States)

    Isaev, V. I.; Iskorkina, A. A.; Lobova, G. A.; Starostenko, V. I.; Tikhotskii, S. A.; Fomin, A. N.

    2018-03-01

    Schemes and criteria are developed for using the measured and modeled geotemperatures for studying the thermal regime of the source rock formations, as well as the tectonic and sedimentary history of sedimentary basins, by the example of the oil fields of the Yamal Peninsula. The method of paleotemperature modeling based on the numerical solution of the heat conduction equation for a horizontally layered solid with a movable upper boundary is used. The mathematical model directly includes the climatic secular trend of the Earth's surface temperature as the boundary condition and the paleotemperatures determined from the vitrinite reflectance as the measurement data. The method does not require a priori information about the nature and intensities of the heat flow from the Earth's interior; the flow is determined by solving the inverse problem of geothermy with a parametric description of the of the sedimentation history and the history of the thermophysical properties of the sedimentary stratum. The rate of sedimentation is allowed to be zero and negative which provides the possibility to take into account the gaps in sedimentation and denudation. The formation, existence, and degradation of the permafrost stratum and ice cover are taken into account as dynamical lithological-stratigraphic complexes with anomalously high thermal conductivity. It is established that disregarding the paleoclimatic factors precludes an adequate reconstruction of thermal history of the source-rock deposits. Revealing and taking into account the Late Eocene regression provided the computationally optimal and richest thermal history of the source-rock Bazhenov Formation, which led to more correct volumetric-genetic estimates of the reserves. For estimating the hydrocarbon reserves in the land territories of the Arctic region of West Siberia by the volumetric-genetic technique, it is recommended to use the Arctic secular trend of temperatures and take into account the dynamics of the

  19. Boron-Doped Carbon Nano-/Microballs from Orthoboric Acid-Starch: Preparation, Characterization, and Lithium Ion Storage Properties

    Directory of Open Access Journals (Sweden)

    Xinhua Lu

    2018-01-01

    Full Text Available A boron-doped carbon nano-/microballs (BC was successfully obtained via a two-step procedure including hydrothermal reaction (180°C and carbonization (800°C with cheap starch and H3BO3 as the carbon and boron source. As a new kind of boron-doped carbon, BC contained 2.03 at% B-content and presented the morphology as almost perfect nano-/microballs with different sizes ranging from 500 nm to 5 μm. Besides that, due to the electron deficient boron, BC was explored as anode material and presented good lithium storage performance. At a current density of 0.2 C, the first reversible specific discharge capacity of BC electrode reached as high as 964.2 mAh g–1 and kept at 699 mAh g–1 till the 11th cycle. BC also exhibited good cycle ability with a specific capacity of 356 mAh g–1 after 79 cycles at a current density of 0.5 C. This work proved to be an effective approach for boron-doped carbon nanostructures which has potential usage for lithium storage material.

  20. Synthesis, spectroscopic and catalytic properties of some new boron hybrid molecule derivatives by BF2 and BPh2 chelation

    Science.gov (United States)

    Kilic, Ahmet; Alcay, Ferhat; Aydemir, Murat; Durgun, Mustafa; Keles, Armagan; Baysal, Akın

    2015-05-01

    A new series of Schiff base ligands (L1-L3) and their corresponding fluorine/phenyl boron hybrid complexes [LnBF2] and [LnBPh2] (n = 1, 2 or 3) have been synthesized and well characterized by both analytical and spectroscopic methods. The Schiff base ligands and their corresponding fluorine/phenyl boron hybrid complexes have been characterized by NMR (1H, 13C and 19F), FT-IR, UV-Vis, LC-MS, and fluorescence spectroscopy as well as melting point and elemental analysis. The fluorescence efficiencies of phenyl chelate complexes are greatly red-shifted compared to those of the fluorine chelate analogs based on the same ligands, presumably due to the large steric hindrance and hard π → π∗ transition of the diphenyl boron chelation, which can effectively prevent molecular aggregation. The boron hybrid complexes were applied to the transfer hydrogenation of acetophenone derivatives to 1-phenylethanol derivatives in the presence of 2-propanol as the hydrogen source. The catalytic studies showed that boron hybrid complexes are good catalytic precursors for transfer hydrogenation of aromatic ketones in 0.1 M iso-PrOH solution. Also, we have found that both steric and electronic factors have a significant impact on the catalytic properties of this class of molecules.

  1. Boron autoradiography method applied to the study of steels

    International Nuclear Information System (INIS)

    Gugelmeier, R.; Barcelo, G.N.; Boado, J.H.; Fernandez, C.

    1986-01-01

    The boron state, contained in the steel microestructure, is determined. The autoradiography by neutrons is used, permiting to obtain boron distribution images by means of additional information which is difficult to acquire by other methods. The application of the method is described, based on the neutronic irradiation of a polished steel sample, over which a celulose nitrate sheet or other appropriate material is fixed to constitute the detector. The particles generated by the neutron-boron interaction affect the detector sheet, which is subsequently revealed with a chemical treatment and can be observed at the optical microscope. In the case of materials used for the construction of nuclear reactors, special attention must be given to the presence of boron, since owing to the exceptionaly high capacity of neutron absorption, lowest quantities of boron acquire importance. The adaption of the method to metallurgical problems allows the obtainment of a correlation between the boron distribution images and the material's microstructure. (M.E.L.) [es

  2. Evolution of anisotropy in bcc Fe distorted by interstitial boron

    Science.gov (United States)

    Gölden, Dominik; Zhang, Hongbin; Radulov, Iliya; Dirba, Imants; Komissinskiy, Philipp; Hildebrandt, Erwin; Alff, Lambert

    2018-01-01

    The evolution of magnetic anisotropy in bcc Fe as a function of interstitial boron atoms was investigated in thin films grown by molecular beam epitaxy. The thermodynamic nonequilibrium conditions during film growth allowed one to stabilize an interstitial boron content of about 14 at .% accompanied by lattice tetragonalization. The c /a ratio scaled linearly with the boron content up to a maximum value of 1.05 at 300 °C substrate growth temperature, with a room-temperature magnetization of. In contrast to nitrogen interstitials, the magnetic easy axis remained in-plane with an anisotropy of approximately -5.1 ×106erg /cm3 . Density functional theory calculations using the measured lattice parameters confirm this value and show that boron local ordering indeed favors in-plane magnetization. Given the increased temperature stability of boron interstitials as compared to nitrogen interstitials, this study will help to find possible ways to manipulate boron interstitials into a more favorable local order.

  3. Synthesis of Boron Nano wires, Nano tubes, and Nano sheets

    International Nuclear Information System (INIS)

    Patel, R.B.; Chou, T.; Iqbal, Z.

    2014-01-01

    The synthesis of boron nano wires, nano tubes, and nano sheets using a thermal vapor deposition process is reported. This work confirms previous research and provides a new method capable of synthesizing boron nano materials. The materials were made by using various combinations of MgB 2 , Mg(BH 4 ) 2 , MCM-41, NiB, and Fe wire. Unlike previously reported methods, a nanoparticle catalyst and a silicate substrate are not required for synthesis. Two types of boron nano wires, boron nano tubes, and boron nano sheets were made. Their morphology and chemical composition were determined through the use of scanning electron microscopy, transmission electron microscopy, and electron energy loss spectroscopy. These boron-based materials have potential for electronic and hydrogen storage applications.

  4. Influence of dopants, particularly carbon, on β-rhombohedral boron

    Science.gov (United States)

    Werheit, H.; Flachbart, K.; Pristáš, G.; Lotnyk, D.; Filipov, V.; Kuhlmann, U.; Shitsevalova, N.; Lundström, T.

    2017-09-01

    Due to the high affinity of carbon to boron, the preparation of carbon-free boron is problematic. Even high-purity (6 N) β-rhombohedral boron contains 30-60 ppm of C. Hence, carbon affects the boron physical properties published so far more or less significantly. We studied well-defined carbon-doped boron samples based on pure starting material carefully annealed with up to about 1% C, thus assuring homogeneity. We present and discuss their electrical conductivity, optical absorption, luminescence and phonon spectra. Earlier attempts of other authors to determine the conductivity of C-doped boron are revised. Our results allow estimating the effects of oxygen and iron doping on the electrical conductivity using results taken from literature. Discontinuities at low T impair the electronic properties.

  5. National History Day 1997 Supplement: Triumph & Tragedy in History.

    Science.gov (United States)

    Gorn, Cathy

    1996-01-01

    Reports on the procedures, standards, and topics involved in the 1997 National History Day. National History Day is a year-long contest where students research primary sources and prepare papers, projects, performances, and media based on a historical theme. The 1997 theme is "Triumph and Tragedy in History." (MJP)

  6. Pulverization of boron element and proportions of boron carbide in boron; Broyage de bore element et dosage de carbure de bore dans le bore

    Energy Technology Data Exchange (ETDEWEB)

    Lang, F M; Finck, C [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1956-07-01

    It is possible to reduce boron element into fine powder by means of a mortar and pestle made of sintered boron carbide, the ratio of boron carbide introduced being less than one per cent. Boron element at our disposal is made of sharp edged, dark brown, little grains of average size greater than 5 {mu}. Grain sizes smaller than 1{mu} are required for applying thin layers of such boron. (author) [French] Il est possible de pulveriser finement du bore element au moyen de mortier et pilon en carbure de bore fritte, le taux de carbure de bore introduit etant inferieur a 1 pour cent. Le bore element dont nous disposons est constitue de petits grains brun fonce, a aretes vives, de dimension moyenne superieure a 5 {mu}. L'application de ce bore en couches minces demande des grains de dimensions inferieures a 1 {mu}. (aute0008.

  7. Characterization of boron doped nanocrystalline diamonds

    International Nuclear Information System (INIS)

    Peterlevitz, A C; Manne, G M; Sampaio, M A; Quispe, J C R; Pasquetto, M P; Iannini, R F; Ceragioli, H J; Baranauskas, V

    2008-01-01

    Nanostructured diamond doped with boron was prepared using a hot-filament assisted chemical vapour deposition system fed with an ethyl alcohol, hydrogen and argon mixture. The reduction of the diamond grains to the nanoscale was produced by secondary nucleation and defects induced by argon and boron atoms via surface reactions during chemical vapour deposition. Raman measurements show that the samples are nanodiamonds embedded in a matrix of graphite and disordered carbon grains, while morphological investigations using field electron scanning microscopy show that the size of the grains ranges from 20 to 100 nm. The lowest threshold fields achieved were in the 1.6 to 2.4 V/μm range

  8. Boron Nitride Nanotube: Synthesis and Applications

    Science.gov (United States)

    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; hide

    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.

  9. CVD mechanism of pyrolytic boron nitride

    International Nuclear Information System (INIS)

    Tanji, H.; Monden, K.; Ide, M.

    1987-01-01

    Pyrolytic boron nitride (P-BN) has become a essential material for III-V compound semiconductor manufacturing process. As the demand from electronics industry for larger single crystals increases, the demand for larger and more economical P-BN components is growing rapidly. P-BN is manufactured by low pressure CVD using boron-trihalides and ammonia as the reactants. In spite that P-BN has been in the market for quite a long time, limited number of fundamental studies regarding the kinetics and the formation mechanism of P-BN have been reported. As it has been demonstrated in CVD of Si, knowledge and both theoretical and empirical modeling of CVD process can be applied to improve the deposition technology and to give more uniform deposition with higher efficiency, and it should also apply to the deposition of P-BN

  10. Facile Synthesis of Ternary Boron Carbonitride Nanotubes

    Directory of Open Access Journals (Sweden)

    Luo Lijie

    2009-01-01

    Full Text Available Abstract In this study, a novel and facile approach for the synthesis of ternary boron carbonitride (B–C–N nanotubes was reported. Growth occurred by heating simple starting materials of boron powder, zinc oxide powder, and ethanol absolute at 1150 °C under a mixture gas flow of nitrogen and hydrogen. As substrate, commercial stainless steel foil with a typical thickness of 0.05 mm played an additional role of catalyst during the growth of nanotubes. The nanotubes were characterized by SEM, TEM, EDX, and EELS. The results indicate that the synthesized B–C–N nanotubes exhibit a bamboo-like morphology and B, C, and N elements are homogeneously distributed in the nanotubes. A catalyzed vapor–liquid–solid (VLS mechanism was proposed for the growth of the nanotubes.

  11. Microadditions of boron and vanadium in ADI

    Directory of Open Access Journals (Sweden)

    Rzychoń T.

    2007-01-01

    Full Text Available In the second part of the study, describing the role of vanadium and boron microadditions in the process of structure formation in heavy-walled castings made from ADI, the results of own investigations were presented. Within this study two series of melts of the ductile iron were made, introducing microadditions of the above mentioned elements to both unalloyed ductile iron and the ductile iron containing high levels of nickel and copper (the composition typical of ADI. Melts were conducted with iron-nickel-magnesium master alloy. Thermal analysis of the solidification process of the cast keel blocks was conducted, the heat treatment of the alloys was carried out, and then the effect of the introduced additions of boron and vanadium on the hardenability of the investigated cast iron was examined and evaluated.

  12. Boron nitride encapsulated graphene infrared emitters

    International Nuclear Information System (INIS)

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

    2016-01-01

    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.

  13. Boron nitride encapsulated graphene infrared emitters

    Energy Technology Data Exchange (ETDEWEB)

    Barnard, H. R.; Zossimova, E.; Mahlmeister, N. H.; Lawton, L. M.; Luxmoore, I. J.; Nash, G. R., E-mail: g.r.nash@exeter.ac.uk [College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter EX4 4QF (United Kingdom)

    2016-03-28

    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.

  14. The spectrophotometric determination of boron in tourmalines

    Directory of Open Access Journals (Sweden)

    LJILJANA JAKSIC

    2005-02-01

    Full Text Available A procedure for the spectrophotometric determination of macro amounts of boron in tourmaline with azomethine H is described. The used tourmaline concentrate was obtained by magnetic separation and heavy-liquids purification of the schorl zone of pegmatite or granite aplite. The samples of tourmaline were decomposed by fusion with anhydrous sodium carbonate and taken up in dilute hydrochloric acid. The interfering effects of iron and aluminium were eliminated by masking with an EDTA – NTA solution. After pH adjustment, the boron was reacted with azomethine H and the absorbance of the obtained coloured complex was measured at 415 nm. The results are compared with those obtained by other procedures. The relative error of the determination was less than 3 %.

  15. Determination of microdistribution of boron in metals

    Energy Technology Data Exchange (ETDEWEB)

    Illic, R; Najzer, M; Rant, J [J. Stefan Institute, Ljubljana (Yugoslavia)

    1976-07-01

    A neutron induced autoradiographic technique was used for the determination of the boron microdistribution in metals. The specimens, which were in close contact with a LR 115 SSTD, were irradiated in the exposure room of the TRIGA Mark II reactor in Ljubljana. The spatial resolution of the autoradiographic image recorded by the LR 115 detector was found to be influenced mainly by the size of the reaction product tracks. The track diameter of a normally etched detector was about 7 {mu}m. An appreciable reduction of track size was achieved by pre-etching the detector foil before neutron irradiation. By this procedure it was possible to obtain a track diameter as small as 1 {mu}m and correspondingly to improve the spatial resolution of the autoradiographs of type EC 80 steel and Al Mg 3 alloy which contain 30 and 2 ppm of boron respectively. (author)

  16. Synthesis and characterization of boron nitrides nanotubes

    International Nuclear Information System (INIS)

    Ferreira, T.H.; Sousa, E.M.B.

    2010-01-01

    This paper presents a new synthesis for the production of boron nitride nanotubes (BNNT) from boron powder, ammonium nitrate and hematite tube furnace CVD method. The samples were subjected to some characterization techniques as infrared spectroscopy, thermal analysis, X-ray diffraction and scanning electron microscopy and transmission. By analyzing the results can explain the chemical reactions involved in the process and confirm the formation of BNNT with several layers and about 30 nanometers in diameter. Due to excellent mechanical properties and its chemical and thermal stability this material is promising for various applications. However, BNNT has received much less attention than carbon nanotubes, it is because of great difficulty to synthesize appreciable quantities from the techniques currently known, and this is one of the main reasons this work.(author)

  17. Grain refinement of cast titanium alloys via trace boron addition

    International Nuclear Information System (INIS)

    Tamirisakandala, S.; Bhat, R.B.; Tiley, J.S.; Miracle, D.B.

    2005-01-01

    The grain size of as-cast Ti-6Al-4V is reduced by about an order of magnitude from 1700 to 200 μm with an addition of 0.1 wt.% boron. A much weaker dependence of reduction in grain size is obtained for boron additions from >0.1% to 1.0%. Similar trends were observed in boron-modified as-cast Ti-6Al-2Sn-4Zr-2Mo-0.1Si

  18. On melting of boron phosphide under pressure

    OpenAIRE

    Solozhenko, Vladimir; Mukhanov, V. A.

    2015-01-01

    Melting of cubic boron phosphide, BP, has been studied at pressures to 9 GPa using synchrotron X-ray diffraction and electrical resistivity measurements. It has been found that above 2.6 GPa BP melts congruently, and the melting curve exhibits negative slope (–60 ± 7 K/GPa), which is indicative of a higher density of the melt as compared to the solid phase.

  19. High resolution imaging of boron carbide microstructures

    International Nuclear Information System (INIS)

    MacKinnon, I.D.R.; Aselage, T.; Van Deusen, S.B.

    1986-01-01

    Two samples of boron carbide have been examined using high resolution transmission electron microscopy (HRTEM). A hot-pressed B 13 C 2 sample shows a high density of variable width twins normal to (10*1). Subtle shifts or offsets of lattice fringes along the twin plane and normal to approx.(10*5) were also observed. A B 4 C powder showed little evidence of stacking disorder in crystalline regions

  20. Contributions to the chemistry of Boron, 112

    International Nuclear Information System (INIS)

    Goetze, R.; Noeth, H.

    1980-01-01

    Several methods were used to prepare a series of boron substituted 1, 3, 2-dithiaborols. The NMR data of this new class of compounds indicate in comparison to 1, 3, 2-dithiaborolanes, that the heterocycle can be looked at as a 6 π-electron system. A high degree of analogy in the mass spectrometric fragmentation of dithiaborolanes and dithiaborols exists, however, the parent ion of 2-methyl dithiaborol is more stable than that of the saturated analogon. (orig.)

  1. Molecular Dynamics Modeling of Piezoelectric Boron Nirtride Nanotubes

    Data.gov (United States)

    National Aeronautics and Space Administration — Conduct a systematic computational study on the physical and electro-mechanical properties of Boron Nitride Nanotubes (BNNTs) to evaluate their functional...

  2. Combustion Performance of a Staged Hybrid Rocket with Boron addition

    Science.gov (United States)

    Lee, D.; Lee, C.

    2018-04-01

    In this paper, the effect of boron on overall system specific impulse was investigated. Additionally, a series of combustion tests was carried out to analyze and evaluate the effect of boron addition on O/F variation and radial temperature profiles. To maintain the hybrid rocket engine advantages, upper limit of boron contents in solid fuel was set to be 10 wt%. The results also suggested that, when adding boron to solid fuel, it helped to provide more uniform radial temperature distribution and also to increase specific impulse by 3.2%.

  3. Deuterated-decaborane using boronization on JT-60U

    Energy Technology Data Exchange (ETDEWEB)

    Yagyu, Jun-ichi; Arai, Takashi; Kaminaga, Atsushi; Miyata, Katsuyuki [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment; Arai, Masaru [Kaihatsu Denki Co., Ltd., Tokyo (Japan)

    2001-03-01

    In JT-60U, boronization using hydride-decaborane (B{sub 10}H{sub 14}) vaporization has been conducted for the first wall conditioning. Compared to other discharge cleaning (DC), boronization is claimed to be efficient in reduction of oxygen impurities and hydrogen recycling in plasma. However, there are some problems in reduction of hydrogen included in boron film and stabilization of DC glow discharge during the boronization. To solve these problems, a new boronization method using deuterated-decaborane (B{sub 10}D{sub 14}) was adopted instead of the conventional hydride-decaborane. As a result, hydrogen content in the boron film decreased clearly and discharge conditioning shots, for decreasing hydrogen content in plasmas, after the boronization were reduced to 1/10 in comparison to the conventional process. Furthermore, DC glow discharge became stable, with only helium carrier gas, and it was possible to save 30 hours in maximum of the time necessary to boronization. It is shown that the boronization using deuterated-decaborane is very efficient and effective method for the first wall conditioning. (author)

  4. Graphite and boron carbide composites made by hot-pressing

    International Nuclear Information System (INIS)

    Miyazaki, K.; Hagio, T.; Kobayashi, K.

    1981-01-01

    Composites consisting of graphite and boron carbide were made by hot-pressing mixed powders of coke carbon and boron carbide. The change of relative density, mechanical strength and electrical resistivity of the composites and the X-ray parameters of coke carbon were investigated with increase of boron carbide content and hot-pressing temperature. From these experiments, it was found that boron carbide powder has a remarkable effect on sintering and graphitization of coke carbon powder above the hot-pressing temperature of 2000 0 C. At 2200 0 C, electrical resistivity of the composite and d(002) spacing of coke carbon once showed minimum values at about 5 to 10 wt% boron carbide and then increased. The strength of the composite increased with increase of boron carbide content. It was considered that some boron from boron carbide began to diffuse substitutionally into the graphite structure above 2000 0 C and densification and graphitization were promoted with the diffusion of boron. Improvements could be made to the mechanical strength, density, oxidation resistance and manufacturing methods by comparing with the properties and processes of conventional graphites. (author)

  5. Dependence of boron cluster dissolution on the annealing ambient

    International Nuclear Information System (INIS)

    Radic, Ljubo; Lilak, Aaron D.; Law, Mark E.

    2002-01-01

    Boron is introduced into silicon via implantation to form p-type layers. This process creates damage in the crystal that upon annealing causes enhanced diffusion and clustering of the boron layer. Reactivation of the boron is not a well-understood process. In this letter we experimentally investigate the effect of the annealing ambient on boron reactivation kinetics. An oxidizing ambient which injects silicon interstitials is compared to an inert ambient. Contrary to published theory, an excess of interstitials does not accelerate the reactivation process

  6. Ion implantation of boron in germanium

    International Nuclear Information System (INIS)

    Jones, K.S.

    1985-05-01

    Ion implantation of 11 B + into room temperature Ge samples leads to a p-type layer prior to any post implant annealing steps. Variable temperature Hall measurements and deep level transient spectroscopy experiments indicate that room temperature implantation of 11 B + into Ge results in 100% of the boron ions being electrically active as shallow acceptor, over the entire dose range (5 x 10 11 /cm 2 to 1 x 10 14 /cm 2 ) and energy range (25 keV to 100 keV) investigated, without any post implant annealing. The concentration of damage related acceptor centers is only 10% of the boron related, shallow acceptor center concentration for low energy implants (25 keV), but becomes dominant at high energies (100 keV) and low doses ( 12 /cm 2 ). Three damage related hole traps are produced by ion implantation of 11 B + . Two of these hole traps have also been observed in γ-irradiated Ge and may be oxygen-vacancy related defects, while the third trap may be divacancy related. All three traps anneal out at low temperatures ( 0 C). Boron, from room temperature implantation of BF 2 + into Ge, is not substitutionally active prior to a post implant annealing step of 250 0 C for 30 minutes. After annealing additional shallow acceptors are observed in BF 2 + implanted samples which may be due to fluorine or flourine related complexes which are electrically active

  7. Considerations for boron neutron capture therapy studies

    International Nuclear Information System (INIS)

    Faria Gaspar, P. de.

    1994-01-01

    Radiotherapy is indispensable as a mean to eradicate deeply or infiltrating tumor tissue that can not be removed surgically. Therefore, it is not selective and may also kill the surrounding health tissue. The principle of BNCT (Boron Neutron Capture Therapy) consist in targeting a tumor selectively with a boron-10 compound. This nuclide has a large capture cross section for thermal neutrons and the nuclear reaction and the delivered energy in locus will selective the tumor. Since its initial proposal in 1963 BNCT has made much progress, however it is not used in a routine treatment. In this work it was approached some complex procedures, as the obtention of selective boron compounds, the adequate set up of neutron beams, the biodistribution, the in vivo and in vitro studies, and also human patients treatments. This work provide fundamentals about BNCT to professional of different areas of knowledge since it comprises multidisciplinary study. It includes appendixes for the ones not related to the field for a better comprehension of the many aspects involved. It is also presented a glossary containing technical and basic aspects involved. It is also presented a glossary containing technical and basic terms referred in the work. (author). 174 refs, 1 fig, 12 apps

  8. Advances in boronization on NSTX-Upgrade

    Directory of Open Access Journals (Sweden)

    C. H Skinner

    2017-08-01

    Full Text Available 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 1–1.5s to 5–8s. A new deuterated tri-methyl boron conditioning system was implemented together with a novel surface analysis diagnostic. 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 correlated with the rise of oxygen emission from the plasma.

  9. Boron determination in U3O8

    International Nuclear Information System (INIS)

    Ogura, Nadia S.; Sarkis, Jorge E.S.; Rosa, Daniele S.; Ulrich, Joao C.

    2009-01-01

    There exist specifications of the concentration as far the limit of impurities in the used uranium compounds is concerned. Among those impurities the boron element is detached. that in the uranium compounds acts as neutron absorber in nuclear reactions. Therefore, the determination of this element in uranium compounds, it is fundamental for the quality and performance of the nuclear fuels. However, the determination of this element is many times prejudiced by the presence of the uranium. For solving this problem, it is performed a chemical separation of the uranium (matrix) out of the interest. The most used methods to accomplish that separation are the solvent extraction and the ion exchange. In this work, the boron concentration will be done through the ion exchange technique, using polypropylene columns and Dowex AG 50W - X8 100-200 mesh cation resin in chloricide medium 0.25 M. The boron concentration will be determined through high resolution inductive coupling plasma mass spectrometry (HRICP-MS)

  10. Stable boron nitride diamondoids as nanoscale materials

    International Nuclear Information System (INIS)

    Fyta, Maria

    2014-01-01

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

  11. A Self-Instructional Course in Student Financial Aid Administration. Module 2--Federal Student Financial Aid: History & Current Sources. Second Edition.

    Science.gov (United States)

    Washington Consulting Group, Inc., Washington, DC.

    The second of 17 modules in a self-instructional course on student financial aid administration, this module offers novice financial aid administrators and other institutional personnel a systematic introduction to the management of federal financial aid programs authorized by the Higher Education Act Title IV. It traces the history of federal…

  12. Clinical treatment planning for subjects undergoing boron neutron capture therapy at Harvard-MIT

    International Nuclear Information System (INIS)

    Zamenhof, R.G.; Palmer, M.R.; Buse, P.M.

    2001-01-01

    Treatment planning is a crucial component of the Harvard-MIT boron neutron capture therapy (BNCT) clinical trials. Treatment planning can be divided into five stages: (1) pre-planning, based on CT and MRI scans obtained when the subject arrives at the hospital and on assumed boron-10 distribution parameters; (2) subject set-up, or simulation, in the MITR-II medical therapy room to determine the boundary conditions for possible set-up configurations; (3) re-planning, following the subject simulation; (4) final localization of the subject in the medical therapy room for BNCT; and (5) final post facto recalculation of the doses delivered based on firm knowledge of the blood boron-10 concentration profiles and the neutron flux histories from precise online monitoring. The computer-assisted treatment planning is done using a specially written BNCT treatment planning code called MacNCTPLAN. The code uses the Los Alamos National Laboratory's Monte Carlo n-particle radiation transport code MCNPv.4b as the dose calculation engine and advanced anatomical model simulation based on an automatic evaluation of CT scan data. Results are displayed as isodose contours and dose-volume histograms, the latter correlated precisely with corresponding anatomical CT or MRI image planes. Examples of typical treatment planning scenarios will be presented. (author)

  13. Doped Boron Carbide-Based Polymers: Fundamental Studies of a Novel Class of Materials for Enhanced Neutron Detection

    Science.gov (United States)

    2016-03-01

    heterojunction diodes fabricated from these films show no evidence of Schottky barrier formation or of significant leakage current in reverse bias [8...all of summer 2012 for this purpose. Related project work: measuring the electronic structure and the surface oxide of thorium oxide ThO2 with Tony...Detecting and Nanoelectronic Applications, Techon 2012. 4. “The History and Development of Boron Carbon Alloy Devices and Rare Earth Heterojunction

  14. Determination of isotopic composition of boron in boron carbide by TIMS and PIGE: an inter-comparison study

    International Nuclear Information System (INIS)

    Sasibhushan, K.; Rao, R.M.; Parab, A.R.; Alamelu, D.; Aggarwal, S.K.; Acharya, R.; Chhillar, S.; Pujari, P.K.

    2015-01-01

    The paper reports a comparison of results on the determination of isotopic composition of boron in boron carbide (B 4 C) samples by Thermal Ionisation Mass Spectrometry (TIMS) and Particle Induced Gamma ray Spectrometry (PIGE). B 4 C samples having varying boron isotopic composition (natural, enriched with respect to 10 B) and their synthetic mixtures) have been analysed by both the techniques. The 10 B atom% was found to be in the range of 20-67%. (author)

  15. Boron neutron capture therapy. Synthesis of boronated amines- and DNA intercalating agents for potential use in cancer therapy

    International Nuclear Information System (INIS)

    Ghaneolhosseini, H.

    1998-01-01

    Boron Neutron Capture Therapy is a binary cancer treatment modality, involving the delivery of a suitable boron compound to tumour cells followed by irradiation of the tumour by thermal neutrons. Boronated agents can selectively be delivered to tumour cells either directly with tumour-specific boron compounds, or by use of targeting strategies. However, the efficacy of this method would increase if the boron agents are localised in the cell nucleus rather than in the cell cytoplasm when neutron irradiation takes place. With these considerations in mind, some boronated DNA intercalating/interacting agents such as phenanthridine- acridine- spermidine- and naphthalimide derivatives were synthesised. Aminoalkyl-o-carboranes were synthesised in order to be used both for coupling to macromolecules and also for halogenation of their corresponding nido-derivatives. The amino groups were introduced using the Gabriel reagent N, N-dibenzyl iminodicarboxylate to provide 1-(aminomethyl)- and 1-(2-aminoethyl)-o-carboranes. The first attempt to achieve the possibility to accumulate a higher concentration of boron atoms in the cell nucleus was to synthesize carboranyl phenanthridinium analogues by reacting a p- or o-carboranyl moiety with phenanthridine, a chromophore with a planar aromatic ring system as DNA intercalator. Boronated acridine-spermidine, boronated diacridine, and boronated dispermidine were obtained in order to increase water solubility to avoid the interaction of these agents with non-DNA sides of the cell, especially membranes; and to enhance the feasibility of a higher DNA-binding constant and also decrease the DNA-drug dissociation rate. Finally, the synthesis of a boronated naphthalimide derivative was carried out by nucleophilic reaction of a primary aminoalkyl-p-carborane with naphthalic anhydride. Biological evaluations on DNA-binding, toxicity, and cellular binding with carboranyl phenanthridinium analogues, boronated acridine- and spermidine are described

  16. The influence of metal Mg on micro-morphology and crystallinity of spherical hexagonal boron nitride

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ning, E-mail: zhangning5832@163.com; Liu, Huan; Kan, Hongmin; Wang, Xiaoyang; Long, Haibo; Zhou, Yonghui

    2015-08-15

    Highlights: • The action mechanism of Mg to the synthesis of spherical BN was explored. • The influence of Mg content on the crystallinity of h-BN powders was studied. • Even if not added any template, the spherical h-BN could be prepared. - Abstract: This search used the boric acid and borax as a source of boron, urea as a nitrogen source, Mg as metal catalyst, and thus prepared different micro-morphology and crystallinity hexagonal boron nitride powders under a flowing ammonia atmosphere at a nitriding temperature of 750 °C. The effect of Mg content on the crystallinity and micro-morphology of hexagonal boron nitride powders was studied, and the Mg action mechanism was explored. Without the added surfactant, the graphitization index (GI) was 6.87, and the diameter of the spherical h-BN was bigger. When the added Mg were 0.1 g, 0.3 g, 0.5 g and 0.7 g, the (GI) decreased to 6.04, 5.67, 4.62 and 4.84, respectively. When the Mg content was higher (0.9 g), GI value increased rapidly, and the crystallinity became bad. When the Mg content was 0.5 g, the dispersion of h-BN powders was at its optimum and refinement apparently, and the crystallinity at its highest.

  17. Online detection of radiation produced in Boron-10 neutron capture reaction: preliminary studies

    International Nuclear Information System (INIS)

    Portu, A.; Galván, V.; González, S.J.; Thorp, S.; Santa Cruz, G.; Saint Martin, G.; Blostein, J.J.

    2013-01-01

    Boron microdistribution in both tumor and normal tissue sections can be studied by the autoradiography technique in solid state nuclear track detectors (SSNTD). A measurement of boron concentration in tissue is obtained through the evaluation of the density of tracks produced by alpha and lithium ions generated in the neutron capture reaction 10B(n,α) 7 Li. This knowledge is pivotal when a BNCT (Boron Neutron Capture Therapy) protocol is considered. A new methodology is proposed in order to record alpha and lithium events in real time, as light spots superimposed to the tissue section image. CCD (Charge-Coupled Device) and CMOS (Complementary Metal Oxide Semiconductor) are used as detectors, with the advantage of avoiding the superposition of events. Commercial web cams were employed for the preliminary experiments. They were partially disassembled in order to get the sensor chip uncovered. These devices were exposed to different radiation sources: 6.118 MeV alpha particles (252Cf), 0.662 MeV gamma rays ( 137 Cs) and thermal neutrons (moderated 241 Am-Be source, 103n.cm2.seg-1), to analyze the characteristics of the respective images. Pictures from tissue sections put in contact with the sensor surface were also acquired. A software was developed in Matlab to perform the image capture and processing. Early results show the feasibility of using these devices to study the distribution 10B in tissue samples. (author)

  18. Determination of boron in graphite, boron carbide and glass by ICP-MS, ICP-OES and conventional wet chemical methods

    International Nuclear Information System (INIS)

    Venkatesh, K.; Kamble, Granthali S.; Venkatesh, Manisha; Kumar, Sanjukta A.; Reddy, A.V.R.

    2014-01-01

    Boron is an important element of interest in nuclear reactor materials due to its high neutron absorption cross section (σ 0 =3837 barns for 10 B). In the present paper, R and D work and routinely used methods have been described for the analysis of case samples (1) Graphite where boron is present at trace levels, (2) Boron Carbide having boron concentration of about 80% and (3) Glass containing 4-6 % boron. (author)

  19. Bohmian histories and decoherent histories

    International Nuclear Information System (INIS)

    Hartle, James B.

    2004-01-01

    The predictions of the Bohmian and the decoherent (or consistent) histories formulations of the quantum mechanics of a closed system are compared for histories--sequences of alternatives at a series of times. For certain kinds of histories, Bohmian mechanics and decoherent histories may both be formulated in the same mathematical framework within which they can be compared. In that framework, Bohmian mechanics and decoherent histories represent a given history by different operators. Their predictions for the probabilities of histories of a closed system therefore generally differ. However, in an idealized model of measurement, the predictions of Bohmian mechanics and decoherent histories coincide for the probabilities of records of measurement outcomes. The formulations are thus difficult to distinguish experimentally. They may differ in their accounts of the past history of the Universe in quantum cosmology

  20. An analysis on boron dilution events during SBLOCA for the KNGR

    International Nuclear Information System (INIS)

    Kim, Young In; Hwang, Young Dong; Park, Jong Kuen; Chung, Young Jong; Sim, Suk Gu

    1999-02-01

    An analysis on boron dilution events during small break loss of coolant accident (LOCA) for Korea Next Generation Reactor (KNGR) was performed using Computational Fluid Dynamic (CFD) computer program FLUENT code. The maximum size of the water slug was determined based on the source of un borated water slug and the possible flow paths. Axisymmetric computational fluid dynamic analysis model is applied for conservative scoping analysis of un borated water slug mixing with recirculation water of the reactor system following small break LOCA assuming one Reactor Coolant Pump (RCP) restart. The computation grid was determined through the sensitivity study on the grid size, which calculates the most conservative results, and the preliminary calculation for boron mixing was performed using the grid. (Author). 17 refs., 3 tabs., 26 figs

  1. Balloon measurement of the isotopic composition of galactic cosmic ray boron, carbon, and nitrogen

    International Nuclear Information System (INIS)

    Zumberge, J.F.

    1981-01-01

    The isotopic compositions of galactic cosmic ray boron, carbon, and nitrogen have been measured at energies near 300 MeV amu -1 , using a balloon-borne instrument at an atmospheric depth of approx. 5 g cm -2 . The calibrations of the detectors comprising the instrument are described. The saturation properties of the cesium iodide scintillators used for measurement of particle energy are studied in the context of analyzing the data for mass. The achieved rms mass resolution varies from approx. 0.3 amu at boron to approx. 0.5 amu at nitrogen, consistent with a theoretical analysis of the contributing factors. A model of galactic propagation and solar modulation is described. Assuming a cosmic ray source composition of solar-like isotopic abundances, the model predicts abundances near earth consistent with the measurements

  2. Easy access to nucleophilic boron through diborane to magnesium boryl metathesis

    Science.gov (United States)

    Pécharman, Anne-Frédérique; Colebatch, Annie L.; Hill, Michael S.; McMullin, Claire L.; Mahon, Mary F.; Weetman, Catherine

    2017-04-01

    Organoboranes are some of the most synthetically valuable and widely used intermediates in organic and pharmaceutical chemistry. Their synthesis, however, is limited by the behaviour of common boron starting materials as archetypal Lewis acids such that common routes to organoboranes rely on the reactivity of boron as an electrophile. While the realization of convenient sources of nucleophilic boryl anions would open up a wealth of opportunity for the development of new routes to organoboranes, the synthesis of current candidates is generally limited by a need for highly reducing reaction conditions. Here, we report a simple synthesis of a magnesium boryl through the heterolytic activation of the B-B bond of bis(pinacolato)diboron, which is achieved by treatment of an easily generated magnesium diboranate complex with 4-dimethylaminopyridine. The magnesium boryl is shown to act as an unambiguous nucleophile through its reactions with iodomethane, benzophenone and N,N'-di-isopropyl carbodiimide and by density functional theory.

  3. Vacuum treatment of CR-39 for the reduction of background in neutron induced autoradiography of boron

    International Nuclear Information System (INIS)

    Freyer, K.; Treutler, H.C.; Dietze, K.; Hunyadi, I.; Csige, I.; Somogyi, G.

    1991-01-01

    The influence of etching time and vacuum processing before, during, and after neutron irradiation on the ''signal/noise'' ratio of the neutron induced autoradiography of boron using CR-39 track detectors has been investigated. The neutron irradiation was carried out in a vacuum chamber using the Cf-252 neutron source of the Central Institute of Isotope and Radiation Research at Leipzig. Hungarian-made CR-39 type track detectors, MA-ND/p and MA-ND/α, produced in different years, are compared. After a few hours of 2 kPa (about 10 -2 Torr) vacuum treatment, the ''signal/noise'' ratio for boron determination is improved remarkably in most cases of the detector and etching-time combinations used. (author)

  4. Vacuum treatment of CR-39 for the reduction of background in neutron induced autoradiography of boron

    Energy Technology Data Exchange (ETDEWEB)

    Freyer, K.; Treutler, H.C.; Dietze, K. (Central Inst. of Isotope and Radiation Research, Leipzig (Germany, F.R.)); Hunyadi, I.; Csige, I.; Somogyi, G. (Magyar Tudomanyos Akademia, Debrecen (Hungary). Atommag Kutato Intezete)

    1991-01-01

    The influence of etching time and vacuum processing before, during, and after neutron irradiation on the ''signal/noise'' ratio of the neutron induced autoradiography of boron using CR-39 track detectors has been investigated. The neutron irradiation was carried out in a vacuum chamber using the Cf-252 neutron source of the Central Institute of Isotope and Radiation Research at Leipzig. Hungarian-made CR-39 type track detectors, MA-ND/p and MA-ND/{alpha}, produced in different years, are compared. After a few hours of 2 kPa (about 10{sup -2} Torr) vacuum treatment, the ''signal/noise'' ratio for boron determination is improved remarkably in most cases of the detector and etching-time combinations used. (author).

  5. An empirical model for parameters affecting energy consumption in boron removal from boron-containing wastewaters by electrocoagulation.

    Science.gov (United States)

    Yilmaz, A Erdem; Boncukcuoğlu, Recep; Kocakerim, M Muhtar

    2007-06-01

    In this study, it was investigated parameters affecting energy consumption in boron removal from boron containing wastewaters prepared synthetically, via electrocoagulation method. The solution pH, initial boron concentration, dose of supporting electrolyte, current density and temperature of solution were selected as experimental parameters affecting energy consumption. The obtained experimental results showed that boron removal efficiency reached up to 99% under optimum conditions, in which solution pH was 8.0, current density 6.0 mA/cm(2), initial boron concentration 100mg/L and solution temperature 293 K. The current density was an important parameter affecting energy consumption too. High current density applied to electrocoagulation cell increased energy consumption. Increasing solution temperature caused to decrease energy consumption that high temperature decreased potential applied under constant current density. That increasing initial boron concentration and dose of supporting electrolyte caused to increase specific conductivity of solution decreased energy consumption. As a result, it was seen that energy consumption for boron removal via electrocoagulation method could be minimized at optimum conditions. An empirical model was predicted by statistically. Experimentally obtained values were fitted with values predicted from empirical model being as following; [formula in text]. Unfortunately, the conditions obtained for optimum boron removal were not the conditions obtained for minimum energy consumption. It was determined that support electrolyte must be used for increase boron removal and decrease electrical energy consumption.

  6. The Boron Isotopic Composition of Elephant Dung: Inputs to the Global Boron Budget

    Science.gov (United States)

    Williams, L. B.; Hervig, R. L.

    2011-12-01

    A survey of boron in kerogen showed isotopically light δ11B values (0 to -50%) that are distinctly different from most mineral and natural water B reservoirs. Diagenesis releases this isotopically light B into pore fluids when hydrocarbons are generated, thus enriching oilfield brines in 10B. This observation suggests that borated biomolecules (BM) are primarily tetrahedral favoring 10B, whereas 11B is preferred in trigonal coordination. Plants, with optimal concentrations up to 100ppm, contribute more B than animal remains to sediment. Elephants are one of the largest herbivores on earth, consuming 200 - 250 kg of plant material/day and producing 50 kg of manure/day. They are inefficient at digestion, thus the manure contains >50% undigested plant material. Dung samples are therefore ideal for studying the δ11B of both the food input and digested output of a significant B supply to sedimentary systems. Horse and rabbit manure were studied for comparison to evaluate B isotope variations in the food supply and potential vital effects on the output. B-content and isotopic composition of dung plant material and digested fractions were measured in the solid state by secondary ion mass spectrometry. The digests were rinsed in 1.8% mannitol, a B-complexing agent, to remove surface adsorbed-B, then air dried and Au-coated for charge compensation. Results showed that the elephant diet contains 3-13 ppm B, with an average δ11B of -20 ± 0.8% (1σ), while rabbit food had 88 ppm B with a δ11B of -50 ± 1.3 %. The digested fraction of the elephant dung contains 4-10ppm B with average δ11B values of -12 ± 1.2%. In comparison, horse manure with 11-21 ppm B has a δ11B of -10.7 ± 0.5% and rabbit manure contains 2-3 ppm B with a δ11B of -8.8 ± 1%. Boron isotope compositions of these manures are indistinguishable (within error). Clearly plant material is a major contributor of isotopically light B to sediments. The herbivores studied fractionate their total B intake in

  7. History Matters

    Institute of Scientific and Technical Information of China (English)

    2017-01-01

    In 2002, she began working as alecturer at Minzu University of China.Now, she teaches English, historicalliterature, ancient Chinese history,historical theory and method, ancientsocial history of China, ancient palacepolitical history of China and the historyof the Sui and Tang dynasties and thePeriod of Five Dynasties.

  8. Research about social, curricular and geographical transversality of a teaching and learning history model based on ojbects as primary sources and classroom museums

    Directory of Open Access Journals (Sweden)

    Glória Solé

    2017-01-01

    Full Text Available The article’s starting point is the problem of perception and understanding of history –which is essential to create a critical citizenship- by future citizens (primary school students as well as future educators (teachers training university students. The article proposes two models of teaching and learning history and its development in two case studies adapted to different ages and geographical contexts (case 1: teachers training degree students of a Spanish university and case 2: Portuguese primary education pupils. Results of the development of the teaching and learning model in both contexts are presented at the same time that the social, curricular and geographical transversality of the model proposed is exposed.

  9. Boron Removal in Radioactive Liquid Waste by Forward Osmosis Membrane

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Dooseong; Choi, Hei Min; Lee, Kune Woo; Moon Jeikwon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    These wastes contain about 0.3-0.8 wt% boric acid and have been concentrated through an evaporation treatment. Boric acid tends to crystallize owing to its solubility, and to plug the evaporator. The volume reduction obtained through evaporation is limited by the amount of boric acid in the waste. As an emerging technology, forward osmosis (FO) has attracted growing interest in wastewater treatment and desalination. FO is a membrane process in which water flows across a semi-permeable membrane from a feed solution of lower osmotic pressure to a draw solution of higher osmotic pressure. However, very few studies on the removal of boron by FO have been performed. The objective of this study is to evaluate the possibility of boron separation in radioactive liquid waste by FO. In this study, the performance of FO was investigated to separate boron in the simulated liquid waste under the factors such as pH, osmotic pressure, ionic strength of the solution, and membrane characteristic. The boron separation in radioactive borate liquid waste was investigated with an FO membrane. When the feed solution containing boron is treated by the FO membrane, the boron permeation 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 in the osmotic driving force. The boron flux of the CTA-ES and ALFD membrane orientation is higher than those of the CTA-NW and ALFF orientation, respectively. The boron permeation rate is constant regardless of the osmotic pressure and membrane orientation. The boron flux decreases slightly with the salt concentration, but it is not heavily influenced at a low salt concentration.

  10. Boron Removal in Radioactive Liquid Waste by Forward Osmosis Membrane

    International Nuclear Information System (INIS)

    Hwang, Dooseong; Choi, Hei Min; Lee, Kune Woo; Moon Jeikwon

    2014-01-01

    These wastes contain about 0.3-0.8 wt% boric acid and have been concentrated through an evaporation treatment. Boric acid tends to crystallize owing to its solubility, and to plug the evaporator. The volume reduction obtained through evaporation is limited by the amount of boric acid in the waste. As an emerging technology, forward osmosis (FO) has attracted growing interest in wastewater treatment and desalination. FO is a membrane process in which water flows across a semi-permeable membrane from a feed solution of lower osmotic pressure to a draw solution of higher osmotic pressure. However, very few studies on the removal of boron by FO have been performed. The objective of this study is to evaluate the possibility of boron separation in radioactive liquid waste by FO. In this study, the performance of FO was investigated to separate boron in the simulated liquid waste under the factors such as pH, osmotic pressure, ionic strength of the solution, and membrane characteristic. The boron separation in radioactive borate liquid waste was investigated with an FO membrane. When the feed solution containing boron is treated by the FO membrane, the boron permeation 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 in the osmotic driving force. The boron flux of the CTA-ES and ALFD membrane orientation is higher than those of the CTA-NW and ALFF orientation, respectively. The boron permeation rate is constant regardless of the osmotic pressure and membrane orientation. The boron flux decreases slightly with the salt concentration, but it is not heavily influenced at a low salt concentration

  11. Deglacial Western Equatorial Pacific pCO2 Reconstruction Using Boron Isotopes of Planktonic Foraminiferas

    Science.gov (United States)

    Kubota, K.; Yokoyama, Y.; Ishikawa, T.; Sagawa, T.; Ikehara, M.; Yamazaki, T.

    2017-12-01

    During the last deglaciation (ca. 19 - 11 ka), partial pressure of CO2 (pCO2) of the atmosphere increased by 80 μatm. Many paleoceanographers point out that the ocean had played an important role in atmospheric CO2 rise, since the ocean have 60 times larger capacity to store carbon compared to the atmosphere. However, evidence on where carbon was transferred from the ocean to the atmosphere is still lacking, hampering our understanding of global carbon cycles in glacial-interglacial timescales. Boron isotope of skeletons of marine calcifying organisms such as corals and foraminiferas can pin down where CO2 source/sink existed, because boron isotopes of marine calcium carbonates is dependent on seawater pH, from which pCO2 of the past seawater can be reconstructed. In previous studies using the boron isotope teqnique, Martinez-Boti et al. (2015, Nature) and Kubota et al. (2014, Scientific Reports) revealed that central and eastern parts of the equatorial Pacific acted as a CO2 source (i.e., CO2 emission) during the last deglaciation, suggesting the equatorial Pacific's contribution to atmospheric CO2 rise. However, some conflicting results have been confirmed in a marine sediment record from the western part of the equatorial Pacific (Palmer & Pearson, 2003, Science), making the conclusion elusive. In this presentation, we will show new results of Mg/Ca, oxygen isotope, and boron isotope measurements during the last 35 ka on two species of surface dwelling foraminiferas (Globigerinoides ruber and G. sacculifer) which was hand-picked separatedly from a well-dated marine sediment core recovered from the West Caroline Basin (KR05-15 PC01) (Yamazaki et al., 2008, GRL). From the new records, we will discuss how the equatorial Pacific behaved during the last deglaciation and how it related to the global carbon cycles.

  12. From the Test Tube to the Treatment Room: Fundamentals of Boron-containing Compounds and their Relevance to Dermatology.

    Science.gov (United States)

    Del Rosso, James Q; Plattner, Jacob J

    2014-02-01

    The development of new drug classes and novel molecules that are brought to the marketplace has been a formidable challenge, especially for dermatologic drugs. The relative absence of new classes of antimicrobial agents is also readily apparent. Several barriers account for slow drug development, including regulatory changes, added study requirements, commercial pressures to bring drugs to market quickly by developing new generations of established compounds, and the greater potential for failure and higher financial risk when researching new drug classes. In addition, the return on investment is usually much lower with dermatologic drugs as compared to the potential revenue from "blockbuster" drugs for cardiovascular or gastrointestinal disease, hypercholesterolemia, and mood disorders. Nevertheless, some researchers are investigating new therapeutic platforms, one of which is boron-containing compounds. Boron-containing compounds offer a wide variety of potential applications in dermatology due to their unique physical and chemical properties, with several in formal phases of development. Tavaborole, a benzoxaborole compound, has been submitted to the United States Food and Drug Administration for approval for treatment of onychomycosis. This article provides a thorough overview of the history of boron-based compounds in medicine, their scientific rationale, physiochemical and pharmacologic properties, and modes of actions including therapeutic targets. A section dedicated to boron-based compounds in development for treatment of various skin disorders is also included.

  13. Histories electromagnetism

    International Nuclear Information System (INIS)

    Burch, Aidan

    2004-01-01

    Working within the HPO (History Projection Operator) Consistent Histories formalism, we follow the work of Savvidou on (scalar) field theory [J. Math. Phys. 43, 3053 (2002)] and that of Savvidou and Anastopoulos on (first-class) constrained systems [Class. Quantum Gravt. 17, 2463 (2000)] to write a histories theory (both classical and quantum) of Electromagnetism. We focus particularly on the foliation-dependence of the histories phase space/Hilbert space and the action thereon of the two Poincare groups that arise in histories field theory. We quantize in the spirit of the Dirac scheme for constrained systems

  14. High pressure synthesis and investigations of properties of boron allotropes and boron carbide

    International Nuclear Information System (INIS)

    Chuvashova, Irina

    2017-01-01

    This work aimed at the development of the high-pressure high-temperature (HPHT) synthesis of single crystals of boron allotropes and boron-rich compounds, which could be used further for precise investigations of their structures, properties, and behavior at extreme conditions. To summarize, the present work resulted in the HPHT synthesis of the first previously unknown non-icosahedral boron allotrope ζ-B. This finding confirmed earlier theoretical predictions, which stayed unproven for decades because of experimental challenges which couldn't be overcome until recently. Structural stability of α-B and β-B in the Mbar pressure range and B 13 C 2 up to 68 GPa was experimentally proven. Accurate measurements of the unit cell and B 12 icosahedra volumes of the stoichiometric boron carbide B 13 C 2 as a function of pressure led to conclusion that they undergo a similar reduction upon compression that is typical for covalently bonded solids. Neither 'molecular-like' nor 'inversed molecular-like' solid behavior upon compression was detected that has closed a long-standing scientific dispute. A comparison of the compressional behavior of B 13 C 2 with that of α-B and γ-B allotropes and B 4 C showed that it is determined by the types of bonding involved in the course of compression.

  15. Comparison of boron and neon damage effects in boron ion-implanted resistors

    International Nuclear Information System (INIS)

    MacIver, B.A.

    1975-01-01

    Boron and neon damage implants were used in fabricating integrated-circuit resistors in silicon. Resistor properties were studied as functions of damaging ion species and dose. Sheet resistances in the 10 000 Ω/square range were obtained with low temperature and voltage sensitivities and d.c. isolation. (author)

  16. From boron analogues of amino acids to boronated DNA: potential new pharmaceuticals and neutron capture agents

    International Nuclear Information System (INIS)

    Spielvogel, B.F.; Sood, Anup; Duke Univ., Durham, NC; Shaw, B.R.; Hall, I.H.

    1991-01-01

    Isoelectronic and isostructural boron analogues of the α-amino acids ranging from simple glycine analogues such as H 3 NBH 2 COOH and Me 2 NHBH 2 COOH to alanine analogues have been synthesised. A diverse variety of analogues, including precursors and derivatives (such as peptides) have potent pharmacological activity, including anticancer, antiinflammatory, analgesic, and hypolipidemic activity in animal model studies and in vitro cell cultures. Boronated nucleosides and (oligo)nucleotides, synthetic oligonucleotide analogues of ''antisense'' agents interact with a complementary nucleic acid sequence blocking the biological effect of the target sequence. Nucleosides boronated on the pyrimidine and purine bases have been prepared. It has been established that an entirely new class of nucleic acid derivatives is feasible in which one of the non-bridging oxygens in the internucleotide phosphodiester linkage can be replaced by an isoelectronic analogue, the borane group, (BH 3 ). The boronated oligonucleotides can be viewed as hybrids of the normal oxygen oligonucleotides and the methylphosphonate oligonucleotides. (author)

  17. Investigation of Hard Boron Rich Solids: Osmium Diboride and β-Rhombohedral Boron

    Science.gov (United States)

    Hebbache, M.; Živković, D.

    Recently, we succeeded in synthesizing three osmium borides, i.e., OsB1.1, Os2B3 and OsB2. Up to date, almost nothing is known about the physical properties of these materials. Microhardness measurements show that OsB2 is extremely hard. Ab initio calculations show that it is due to formation of covalent bonds between boron atoms. OsB2 is also a low compressibility material. It can be used for hard coatings. The β-rhombohedral polymorph of boron is the second hardest elemental crystal (H ≈ 33 GPa). It is also very light and a p-type semiconductor. In early 1970s, it has been shown that the doping of boron with 3d transition elements enhances its hardness by about 25%. We predict that, in general, heavily doped samples MBx, with x ≤ 31 or equivalently a dopant concentration larger than 3.2 at.%, should be ultrahard, i.e., H > 43 GPa. The relevant dopants M are Al, Cu, Sc, Mn, Mg and Li. In addition to these properties, boron-rich materials have a very low volatility, a high chemical inertness and high melting point. They are suitable for applications under extreme conditions and thermoelectric equipment.

  18. Boron distribution and the effect of lime on boron uptake by pansy, petunia, and gerbera plants

    Science.gov (United States)

    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...

  19. High pressure synthesis and investigations of properties of boron allotropes and boron carbide

    Energy Technology Data Exchange (ETDEWEB)

    Chuvashova, Irina

    2017-06-12

    This work aimed at the development of the high-pressure high-temperature (HPHT) synthesis of single crystals of boron allotropes and boron-rich compounds, which could be used further for precise investigations of their structures, properties, and behavior at extreme conditions. To summarize, the present work resulted in the HPHT synthesis of the first previously unknown non-icosahedral boron allotrope ζ-B. This finding confirmed earlier theoretical predictions, which stayed unproven for decades because of experimental challenges which couldn't be overcome until recently. Structural stability of α-B and β-B in the Mbar pressure range and B{sub 13}C{sub 2} up to 68 GPa was experimentally proven. Accurate measurements of the unit cell and B{sub 12} icosahedra volumes of the stoichiometric boron carbide B{sub 13}C{sub 2} as a function of pressure led to conclusion that they undergo a similar reduction upon compression that is typical for covalently bonded solids. Neither 'molecular-like' nor 'inversed molecular-like' solid behavior upon compression was detected that has closed a long-standing scientific dispute. A comparison of the compressional behavior of B{sub 13}C{sub 2} with that of α-B and γ-B allotropes and B{sub 4}C showed that it is determined by the types of bonding involved in the course of compression.

  20. Dynamic response of multiwall boron nitride nanotubes subjected to ...

    Indian Academy of Sciences (India)

    Page 1 ... 1. Introduction. Boron nitride nanotubes (BNNTs) are like carbon nanotubes. (CNTs) in structure in which carbon atoms are replaced by alternate boron and nitrogen atoms. Thus, BNNTs demon- ... istic analyser for intermediate landing situation of inserted mass.15 Also, a macroscopic continuum simulation is sug-.

  1. Highly thermal conductive carbon fiber/boron carbide composite material

    International Nuclear Information System (INIS)

    Chiba, Akio; Suzuki, Yasutaka; Goto, Sumitaka; Saito, Yukio; Jinbo, Ryutaro; Ogiwara, Norio; Saido, Masahiro.

    1996-01-01

    In a composite member for use in walls of a thermonuclear reactor, if carbon fibers and boron carbide are mixed, since they are brought into contact with each other directly, boron is reacted with the carbon fibers to form boron carbide to lower thermal conductivity of the carbon fibers. Then, in the present invention, graphite or amorphous carbon is filled between the carbon fibers to provide a fiber bundle of not less than 500 carbon fibers. Further, the surface of the fiber bundle is coated with graphite or amorphous carbon to suppress diffusion or solid solubilization of boron to carbon fibers or reaction of them. Then, lowering of thermal conductivity of the carbon fibers is prevented, as well as the mixing amount of the carbon fiber bundles with boron carbide, a sintering temperature and orientation of carbon fiber bundles are optimized to provide a highly thermal conductive carbon fiber/boron carbide composite material. In addition, carbide or boride type short fibers, spherical graphite, and amorphous carbon are mixed in the boron carbide to prevent development of cracks. Diffusion or solid solubilization of boron to carbon fibers is reduced or reaction of them if the carbon fibers are bundled. (N.H.)

  2. Eleventh international conference on boron chemistry. Programme and abstracts

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-07-01

    Abstracts of reports at the Eleventh International Conference on Boron Chemistry are presented. Born chemistry as a connecting bridge between many fields maintains one of the leading positions in modern chemistry. Methods of synthesis of different boron compounds, properties of the compounds, their use in other regions of chemistry and medicine are widely presented in reports.

  3. Feasibility study of SMART core with soluble boron

    International Nuclear Information System (INIS)

    Kim, Kang Seog; Lee, Chung Chan; Zee, Sung Quun

    2000-11-01

    The excess reactivity of SMART core without soluble boron is effectively controlled by 49 CEDM. We suggest another method to control the core excess reactivity using both the checkerboard type of 25 CEDM and soluble boron and perform a feasibility calculation. The soluble boron operation is categorized into the on-line and the off-line mechanisms. The former is to successively control the boron concentration according to the excess reactivity during operation and the latter is to add and change some soluble boron during refueling and repairing. Since the on-line soluble boron control system of SMART is conceptually identical to that of the commercial pressurized water reactor, we did not perform the analysis. Since the soluble boron in the complete off-line system increases the moderator temperature coefficient, the reactivity defect between hot and cold moderator temperature is decreased. However, the decrease of the reactivity is not big to satisfy the core reactivity limits. When using 25 CEDM, the possible mechanism is to control the excess reactivity by both control rod and on-line boron control mechanism between cold and hot zero power and by only control rod at hot full power. We selected the loading pattern satisfying the requirement in the view of nuclear design

  4. Mass spectrometric investigation of vinyl-substituted organic boron compounds

    International Nuclear Information System (INIS)

    Tarielashvili, V.O.; Ordzhonikidze, K.G.; Parulava, L.P.; Vakhaniya, G.V.

    1992-01-01

    Mass spectrometric investigation of vinyl-substituted organic compounds was conducted. Ionization was performed by electron shock. Possibility of determining boron isotope content is all analyzed organic boron vinyl-substituted compounds by direct method is shown. This simplifies sufficiently and lowers the price of analysis, improves its accuracy and rapidity

  5. Determination of free and combined carbon in boron carbide

    International Nuclear Information System (INIS)

    Shankaran, P.S.; Kulkarni, Amit S.; Pandey, K.L.; Ramanjaneyulu, P.S.; Yadav, C.S.; Sayi, Y.S.; Ramakumar, K.L.

    2009-01-01

    A simple, sensitive and fast method for the determination of free and combined carbon in boron carbide samples, based on combustion in presence of oxygen at different temperatures, has been developed. Method has been standardized by analyzing mixture of two different boron carbide samples. Error associated with the method in the determination of free carbon is less than 5%. (author)

  6. The investigation of parameters affecting boron removal by electrocoagulation method

    Energy Technology Data Exchange (ETDEWEB)

    Yilmaz, A. Erdem [Department of Environmental Engineering, Atatuerk University, Faculty of Engineering, Erzurum (Turkey)]. E-mail: aerdemy@atauni.edu.tr; Boncukcuoglu, Recep [Department of Environmental Engineering, Atatuerk University, Faculty of Engineering, Erzurum (Turkey); Kocakerim, M. Muhtar [Department of Chemical Engineering, 25240, Atatuerk University, Faculty of Engineering Erzurum (Turkey); Keskinler, Buelent [Department of Environmental Engineering, Gebze Institute of Technology, Gebze/Kocaeli 41400 (Turkey)

    2005-10-17

    Boron removal from wastewaters by electrocoagulation using aluminum electrode material was investigated in this paper. Several working parameters, such as pH, current density, boron concentration and type and concentration of supporting electrolyte were studied in an attempt to achieve a higher removal capacity. The experiments were carried out by keeping the pH of solution constant and optimum pH of solution was determined 8.0 for the aluminum electrode. Although energy consumption increased with decreasing boron concentration, which conductivity of these solutions were low, boron removal efficiency was higher at 100 mg/L than that of 1000 mg/L. Current density was an important parameter affecting removal efficiency. Boron removal efficiency and energy consumption increased with increasing current density from 1.2 to 6.0 mA/cm{sup 2}. The types of different supporting electrolyte were experimented in order to investigate to this parameter effect on boron removal. The highest boron removal efficiency, 97%, was found by CaCl{sub 2}. Added CaCl{sub 2} increased more the conductivity of solution according to other supporting electrolytes, but decreased energy consumption. The results showed to have a high effectiveness of the electrocoagulation method in removing boron from aqueous solutions.

  7. The investigation of parameters affecting boron removal by electrocoagulation method

    International Nuclear Information System (INIS)

    Yilmaz, A. Erdem; Boncukcuoglu, Recep; Kocakerim, M. Muhtar; Keskinler, Buelent

    2005-01-01

    Boron removal from wastewaters by electrocoagulation using aluminum electrode material was investigated in this paper. Several working parameters, such as pH, current density, boron concentration and type and concentration of supporting electrolyte were studied in an attempt to achieve a higher removal capacity. The experiments were carried out by keeping the pH of solution constant and optimum pH of solution was determined 8.0 for the aluminum electrode. Although energy consumption increased with decreasing boron concentration, which conductivity of these solutions were low, boron removal efficiency was higher at 100 mg/L than that of 1000 mg/L. Current density was an important parameter affecting removal efficiency. Boron removal efficiency and energy consumption increased with increasing current density from 1.2 to 6.0 mA/cm 2 . The types of different supporting electrolyte were experimented in order to investigate to this parameter effect on boron removal. The highest boron removal efficiency, 97%, was found by CaCl 2 . Added CaCl 2 increased more the conductivity of solution according to other supporting electrolytes, but decreased energy consumption. The results showed to have a high effectiveness of the electrocoagulation method in removing boron from aqueous solutions

  8. Effect of boron on growth criteria of some wheat cultivars

    Directory of Open Access Journals (Sweden)

    Ashraf Metwally

    2012-01-01

    Full Text Available Introduction: Toxic soil concentrations of the essential micronutrient boron (B represent major limitations to crop production worldwide. Plants have a range of defense systems that might be involved in their affinity to resist and tolerate nutrients stress.Materials and methods: The experiments were carried out to study the differential responses in five wheat cultivars to boron toxicity. Results: The fresh and dry matter yield of the test wheat cultivars showed marked decrease as the concentration of boron was increased. Elevated concentration of boron had a notable inhibitory effect on the biosynthesis of pigments fractions in the test wheat cultivars as severely as dry matter gain. The adverse concentration effects of boron on some metabolic responses were clearly displayed by shoot and root systems, exhibited in the elevated rates of proline, hydrogen peroxide and malondialdehyde formation. Potassium leakage was severely affected by boron-stress in some cultivars at all tested concentrations, while in some others a moderate damage was manifested only at the higher boron concentrations.Conclusions: Sakha 93 out of all the different cultivars investigated was found to display the lowest sensitivity to boron-stress, while Gemmeza 9 was the most sensitive one.

  9. New applications of the interaction between diols and boronic acids

    NARCIS (Netherlands)

    Duval, F.L.

    2015-01-01

    Florine Duval - New applications of the interaction between diols and boronic acids – Summary

    Chapter 1 introduces the theory and known applications of the interaction between boronic acids and diols, and explains the context of this thesis. Diagnosis of

  10. Preparation of boron-nitrogen films by sputtering

    International Nuclear Information System (INIS)

    Klose, S.; Winde, B.

    1980-01-01

    Hard boron-nitrogen films adherent to various substrates can be prepared by sputtering. IR investigations suggest the existence of cubic boron nitride in certain layers. Transmission electron microscope studies have shown a quasi-amorphous structure irregularly incorporating crystallites of zinc blende structure of some nm in diameter

  11. Production of boron carbide powder by carbothermal synthesis of ...

    Indian Academy of Sciences (India)

    TECS

    weight armour plates etc (Alizadeh et al 2004). It can also be used as a reinforcing material for ceramic matrix composites. It is an excellent neutron absorption material in nuclear industry due to its high neutron absorption co- efficient (Sinha et al 2002). Boron carbide can be prepared by reaction of elemental boron and ...

  12. Eleventh international conference on boron chemistry. Programme and abstracts

    International Nuclear Information System (INIS)

    2002-01-01

    Abstracts of reports at the Eleventh International Conference on Boron Chemistry are presented. Born chemistry as a connecting bridge between many fields maintains one of the leading positions in modern chemistry. Methods of synthesis of different boron compounds, properties of the compounds, their use in other regions of chemistry and medicine are widely presented in reports [ru

  13. Boron Diffusion in Surface-Treated Framing Lumber

    Science.gov (United States)

    Patricia K. Lebow; Stan T. Lebow; Steven A. Halverson

    2013-01-01

    The extent of boron penetration in framing lumber treated by spray applications during construction is not well quantified. This study evaluated the effect of formulation and concentration on diffusion of boron in lumber specimens that were equilibrated in conditions that produced wood moisture contents of 18 to 21 percent. One set of specimens was pressure treated...

  14. Design, Fabrication and Performance of Boron-Carbide Control Elements

    International Nuclear Information System (INIS)

    Brammer, H.A.; Jacobson, J.

    1964-01-01

    A control blade design, incorporating boron-carbide (B 4 C) in stainless-steel tubes, was introduced into service in boiling water reactors in April 1961. Since that time this blade has become the standard reference control element in General Electric boiling-water reactors, replacing the 2% boron-stainless-steel blades previously used. The blades consist of a sheathed, cruciform array of small vertical stainless-steel tubes filled with compácted boron-carbide powder. The boron-carbide powder is confined longitudinally into several independent compartments by swaging over ball bearings located inside the tubes. The development and use of boron-carbide control rods is discussed in five phases: 1. Summary of experience with boron-steel blades and reasons for transition to boron-carbide control; 2. Design of the boron-carbide blade, beginning with developmental experiments, including early measurements performed in the AEC ''Control Rod Material and Development Program'' at the Vallecitos Atomic Laboratory, through a description of the final control blade configuration; 3. Fabrication of the blades and quality control procedures; 4. Results of confirmatory pre-operational mechanical and reactivity testing; and 5. Post-operational experience with the blades, including information on the results of mechanical inspection and reactivity testing after two years of reactor service. (author) [fr

  15. Problems and possibilities of development of boron nitride ceramics

    International Nuclear Information System (INIS)

    Rusanova, L.N.; Romashin, A.G.; Kulikova, G.I.; Golubeva, O.P.

    1988-01-01

    The modern state of developments in the field of technology of ceramics produced from boron nitride is analyzed. Substantial difficulties in production of pure ceramics from hexagonal and wurtzite-like boron nitride are stated as related to the structure peculiarities and inhomogeneity of chemical bonds in elementary crystal cells of various modifications. Advantages and disadvantages of familiar technological procedures in production of boron nitride ceramics are compared. A new technology is suggested, which is based on the use of electroorganic compounds for hardening and protection of porous high-purity boron-nitride die from oxidation, and as high-efficient sintered elements for treatment of powders of various structures and further pyrolisis. The method is called thermal molecular lacing (TML). Properties of ceramics produced by the TML method are compared with characteristics of well-known brands of boron nitride ceramics

  16. Fracture toughness of borides formed on boronized ductile iron

    International Nuclear Information System (INIS)

    Sen, Ugur; Sen, Saduman; Koksal, Sakip; Yilmaz, Fevzi

    2005-01-01

    In this study, fracture toughness properties of boronized ductile iron were investigated. Boronizing was realized in a salt bath consisting of borax, boric acid and ferro-silicon. Boronizing heat treatment was carried out between 850 and 950 deg. C under the atmospheric pressure for 2-8 h. Borides e.g. FeB, Fe 2 B formed on ductile iron was verified by X-ray diffraction (XRD) analysis, SEM and optical microscope. Experimental results revealed that longer boronizing time resulted in thicker boride layers. Optical microscope cross-sectional observation of borided layers showed dentricular morphology. Both microhardness and fracture toughness of borided surfaces were measured via Vickers indenter. The harnesses of borides formed on the ductile iron were in the range of 1160-2140 HV 0.1 and fracture toughness were in the range of 2.19-4.47 MPa m 1/2 depending on boronizing time and temperature

  17. Morphological and electrochemical studies of spherical boron doped diamond electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Mendes de Barros, R.C. [IQ/USP, Av. Lineu Prestes, 748, Bloco 2 Superior, Cidade Universitaria, Sao Paulo/SP, 05508-900 (Brazil); Ferreira, N.G. [LAS/INPE, Av. dos Astronautas, 1758, Jardim da Granja, Sao Jose dos Campos/SP, 12245-970 (Brazil); Azevedo, A.F. [LAS/INPE, Av. dos Astronautas, 1758, Jardim da Granja, Sao Jose dos Campos/SP, 12245-970 (Brazil); Corat, E.J. [LAS/INPE, Av. dos Astronautas, 1758, Jardim da Granja, Sao Jose dos Campos/SP, 12245-970 (Brazil); Sumodjo, P.T.A. [IQ/USP, Av. Lineu Prestes, 748, Bloco 2 Superior, Cidade Universitaria, Sao Paulo/SP, 05508-900 (Brazil); Serrano, S.H.P. [IQ/USP, Av. Lineu Prestes, 748, Bloco 2 Superior, Cidade Universitaria, Sao Paulo/SP, 05508-900 (Brazil)]. E-mail: shps@iq.usp.br

    2006-08-14

    Morphological and electrochemical characteristics of boron doped diamond electrode in new geometric shape are presented. The main purpose of this study is a comparison among voltammetric behavior of planar glassy carbon electrode (GCE), planar boron doped diamond electrode (PDDE) and spherical boron doped diamond electrode (SDDE), obtained from similar experimental parameters. SDDE was obtained by the growth of boron doped film on textured molybdenum tip. This electrode does not present microelectrode characteristics. However, its voltammetric peak current, determined at low scan rates, is largest associated to the smallest {delta}E {sub p} values for ferrocyanide system when compared with PDDE or GCE. In addition, the capacitance is about 200 times smaller than that for GCE. These results show that the analytical performance of boron doped diamond electrodes can be implemented just by the change of sensor geometry, from plane to spherical shape.

  18. Boron effect on stainless steel plasticity under hot deformation

    International Nuclear Information System (INIS)

    Bulat, S.I.; Kardonov, B.A.; Sorokina, N.A.

    1978-01-01

    The effect of boron on plasticity of stainless steels at temperatures of hot deformation has been studied at three levels of alloying, i.e. 0-0.01% (micro-alloying or modifying), 0.01-0.02% (low alloying) and 0.02-2.0% (high alloying). Introduction of 0.001-0.005% of boron increases hot plasticity of both low and high carbon stainless steels due to decrease in grain size and strengthening of grain boundaries. Microalloying by boron has a positive effect at temperatures below 1200-1220 deg C. At higher temperatures, particularly when its content exceeds 0.008%, boron deteriorates plasticity by increasing the size of grains and weakening their boundaries. 0.1-2% boron strengthen the stainless steel and dectease its plasticity

  19. Impact of Boron pollution to Biota Marine aquatic

    International Nuclear Information System (INIS)

    Heni Susiati; Yarianto-SBS; Imam Hamzah; Fepriadi

    2003-01-01

    Power plants and industrial facilities can release potentially harmful chemicals, like boron through direct aqueous discharges or cycling of cooling water to aquatic ecosystems environmental at plant surrounding. Boron is an essential trace element for the growth of marine biota, but can be toxic in excessive amount. Therefore will adversely affect of growth, reproduction or survival. Toxicity to aquatic organism, including vertebrates, invertebrates and plants can vary depending on the organism's life stage and environment. It is recommended that the maximum concentration of total boron for the protection of marine aquatic life should not exceed 1,2 mg B/L. Early stages of life cycle are more sensitive to boron than later ones, and the use of reconstituted water shows higher toxicity in lower boron concentrations than natural waters. (author)

  20. Additive Manufacturing of Dense Hexagonal Boron Nitride Objects

    Energy Technology Data Exchange (ETDEWEB)

    Marquez Rossy, Andres E [ORNL; Armstrong, Beth L [ORNL; Elliott, Amy M [ORNL; Lara-Curzio, Edgar [ORNL

    2017-05-12

    The feasibility of manufacturing hexagonal boron nitride objects via additive manufacturing techniques was investigated. It was demonstrated that it is possible to hot-extrude thermoplastic filaments containing uniformly distributed boron nitride particles with a volume concentration as high as 60% and that these thermoplastic filaments can be used as feedstock for 3D-printing objects using a fused deposition system. Objects 3D-printed by fused deposition were subsequently sintered at high temperature to obtain dense ceramic products. In a parallel study the behavior of hexagonal boron nitride in aqueous solutions was investigated. It was shown that the addition of a cationic dispersant to an azeotrope enabled the formulation of slurries with a volume concentration of boron nitride as high as 33%. Although these slurries exhibited complex rheological behavior, the results from this study are encouraging and provide a pathway for manufacturing hexagonal boron nitride objects via robocasting.

  1. Boron determination in tourmaline by neutron induced radiography

    Energy Technology Data Exchange (ETDEWEB)

    Qureshi, A.A. E-mail: aaqureshi@pinstech.org.pk; Akram, M.; Ayub Khan, M.; Khattak, N.U.; Qureshi, I.E.; Khan, H.A

    2001-06-01

    The technique of neutron induced radiography has been applied to determine the boron concentration and its spatial distribution in mineral tourmaline collected from Swat Tourmaline Granite, Northern Pakistan. The technique involves the simultaneous irradiation of sample and a standard fixed on a track detector with thermal neutrons and the counting of alpha and {sup 7}Li tracks produced in the detector from the nuclear reaction {sup 10}B(n,{alpha}){sup 7}Li. Boron concentration is determined by comparing the {sup 7}Li and alpha particle tracks density with that of a standard of known boron concentration. Boron concentration in tourmaline has been found to be (3.40{+-}0.01)% in this study which is on the upper side within the normal range (2.5-3.8)% reported in the world. The presence of somewhat higher concentration of boron in tourmaline indicates that the Swat Tourmaline Granite was generated as a late stage hydrothermal activity during the Himalayan Orogeny.

  2. A Limousin-French dictionary as a source on the history of cooking : Potatoes in the Tulle area (Corrèze, France) in the early 19th century

    OpenAIRE

    Chastanet, Monique

    2010-01-01

    Des erreurs ayant été commises dans le travail éditorial, le texte de référence est celui qui figure sur ce site.; International audience; The words of a language, when documented for a specific period, may serve as a valuable historical source. For the history of cooking, a good example can be seen in a Limousin-French dictionary published at Tulle (Corrèze, France) in 1823. It shows, through certain terms and expressions, the earliest uses of the potato in the cooking of this region. It is ...

  3. Numerical simulation of boron injection in a BWR

    Energy Technology Data Exchange (ETDEWEB)

    Tinoco, Hernan, E-mail: htb@forsmark.vattenfall.s [Forsmarks Kraftgrupp AB, SE-742 03 Osthammar (Sweden); Buchwald, Przemyslaw [Reactor Technology, Royal Institute of Technology, SE-100 44 Stockholm (Sweden); Frid, Wiktor, E-mail: wiktor@reactor.sci.kth.s [Reactor Technology, Royal Institute of Technology, SE-100 44 Stockholm (Sweden)

    2010-02-15

    The present study constitutes a first step to understand the process of boron injection, transport and mixing in a BWR. It consists of transient CFD simulations of boron injection in a model of the downcomer of Forsmark's Unit 3 containing about 6 million elements. The two cases studied are unintentional start of boron injection under normal operation and loss of offsite power with partial ATWS leaving 10% of the core power uncontrolled. The flow conditions of the second case are defined by means of an analysis with RELAP5, assuming boron injection start directly after the first ECCS injection. Recent publications show that meaningful conservative results may be obtained for boron or thermal mixing in PWRs with grids as coarse as that utilized here, provided that higher order discretization schemes are used to minimize numerical diffusion. The obtained results indicate an apparently strong influence of the scenario in the behavior of the injection process. The normal operation simulation shows that virtually all boron solution flows down to the Main Recirculation Pump inlet located directly below the boron inlet nozzle. The loss of offsite power simulation shows initially a spread of the boron solution over the entire sectional area of the lower part of the downcomer filled with colder water. This remaining effect of the ECCS injection lasts until all this water has left the downcomer. Above this region, the boron injection jet develops in a vertical streak, eventually resembling the injection of the normal operation scenario. Due to the initial spread, this boron injection will probably cause larger temporal and spatial concentration variations in the core. In both cases, these variations may cause reactivity transients and fuel damage due to local power escalation. To settle this issue, an analysis using an extended model containing the downcomer, the MRPs and the Lower Plenum will be carried out. Also, the simulation time will be extended to a scale of

  4. Numerical simulation of boron injection in a BWR

    International Nuclear Information System (INIS)

    Tinoco, Hernan; Buchwald, Przemyslaw; Frid, Wiktor

    2010-01-01

    The present study constitutes a first step to understand the process of boron injection, transport and mixing in a BWR. It consists of transient CFD simulations of boron injection in a model of the downcomer of Forsmark's Unit 3 containing about 6 million elements. The two cases studied are unintentional start of boron injection under normal operation and loss of offsite power with partial ATWS leaving 10% of the core power uncontrolled. The flow conditions of the second case are defined by means of an analysis with RELAP5, assuming boron injection start directly after the first ECCS injection. Recent publications show that meaningful conservative results may be obtained for boron or thermal mixing in PWRs with grids as coarse as that utilized here, provided that higher order discretization schemes are used to minimize numerical diffusion. The obtained results indicate an apparently strong influence of the scenario in the behavior of the injection process. The normal operation simulation shows that virtually all boron solution flows down to the Main Recirculation Pump inlet located directly below the boron inlet nozzle. The loss of offsite power simulation shows initially a spread of the boron solution over the entire sectional area of the lower part of the downcomer filled with colder water. This remaining effect of the ECCS injection lasts until all this water has left the downcomer. Above this region, the boron injection jet develops in a vertical streak, eventually resembling the injection of the normal operation scenario. Due to the initial spread, this boron injection will probably cause larger temporal and spatial concentration variations in the core. In both cases, these variations may cause reactivity transients and fuel damage due to local power escalation. To settle this issue, an analysis using an extended model containing the downcomer, the MRPs and the Lower Plenum will be carried out. Also, the simulation time will be extended to a scale of several

  5. Packing C60 in Boron Nitride Nanotubes

    Science.gov (United States)

    Mickelson, W.; Aloni, S.; Han, Wei-Qiang; Cumings, John; Zettl, A.

    2003-04-01

    We have created insulated C60 nanowire by packing C60 molecules into the interior of insulating boron nitride nanotubes (BNNTs). For small-diameter BNNTs, the wire consists of a linear chain of C60 molecules. With increasing BNNT inner diameter, unusual C60 stacking configurations are obtained (including helical, hollow core, and incommensurate) that are unknown for bulk or thin-film forms of C60. C60 in BNNTs thus presents a model system for studying the properties of dimensionally constrained ``silo'' crystal structures. For the linear-chain case, we have fused the C60 molecules to form a single-walled carbon nanotube inside the insulating BNNT.

  6. Stability analysis of zigzag boron nitride nanoribbons

    Energy Technology Data Exchange (ETDEWEB)

    Rai, Hari Mohan, E-mail: rai.2208@gmail.com; Late, Ravikiran; Saxena, Shailendra K.; Kumar, Rajesh; Sagdeo, Pankaj R. [Indian Institute of Technology, Indore –452017 (India); Jaiswal, Neeraj K. [Discipline of Physics, PDPM- Indian Institute of Information Technology, Design and Manufacturing, Jabalpur – 482005 (India); Srivastava, Pankaj [Computational Nanoscience and Technology Lab. (CNTL), ABV- Indian Institute of Information Technology and Management, Gwalior – 474015 (India)

    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)

  7. Magnesium doping of boron nitride nanotubes

    Science.gov (United States)

    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.

  8. Synthesis of boron-containing heterocyclic compounds

    International Nuclear Information System (INIS)

    Azev, Yuri; Slepukhina, Irina; Gabel, Detlef

    2004-01-01

    The synthesis of boron-containing 1,3,5-triazines and 1,2,4-triazines is described. Derivatives of 1,3,5-triazine containing the o-carborane cluster have been obtained by reacting the corresponding propargyl derivatives with B 10 H 14 . Derivatives of 1,2,4-triazine containing the B 12 H 12 2- cluster have been obtained by nucleophilic substitution of ethylsulfone derivatives with B 12 H 11 SH 2- . They have been isolated in their ring-protonated form. Reaction of RNH 2 -B 8 H 11 NH-R with stericly demanding heterocycles failed, either for steric or for solubility reasons

  9. Salinity’s influence on boron toxicity in broccoli: II. Impacts on boron uptake, uptake mechanisms and tissue ion relations.

    Science.gov (United States)

    Limited research has been conducted on the interactive effects of salinity and boron stresses on plants despite their common occurrence in natural systems. The purpose of this research was to determine and quantify the interactive effects of salinity, salt composition and boron on broccoli (Brassica...

  10. Continued biological investigations of boron-rich oligomeric phosphate diesters (OPDs). Tumor-selective boron agents for BNCT

    International Nuclear Information System (INIS)

    Lee, Mark W.; Shelly, Kenneth; Kane, Robert R.; Hawthorne, M. Frederick

    2006-01-01

    Clinical success of Boron Neutron Capture Therapy will rely on the selective intracellular delivery of high concentrations of boron-10 to tumor tissue. In order for a boron agent to facilitate clinical success, the simultaneous needs of obtaining a high tumor dose, high tumor selectivity, and low systemic toxicity must be realized. Boron-rich oligomeric phosphate diesters (OPDs) are a class of highly water-soluble compounds containing up to 40% boron by weight. Previous work in our groups demonstrated that once placed in the cytoplasm of tumor cells, OPDs quickly accumulate within the cell nucleus. The objective of the current study was to determine the biodistribution of seven different free OPDs in BALB/c mice bearing EMT6 tumors. Fructose solutions containing between 1.4 and 6.4 micrograms of boron per gram of tissue were interveinously injected in mice seven to ten days after tumor implantation. At intervals during the study, animals were euthanized and samples of tumor, blood, liver, kidney, brain and skin were collected and analyzed for boron content using ICP-AES. Tumor boron concentrations of between 5 and 29 ppm were achieved and maintained over the 72-hour time course of each experiment. Several OPDs demonstrated high tumor selectivity with one oligomer exhibiting a tumor to blood ratio of 35:1. The apparent toxicity of each oligomer was assessed through animal behavior during the experiment and necropsy of each animal upon sacrifice. (author)

  11. Meeting the challenge of homogenous boron targeting of heterogeneous tumors for effective boron neutron capture therapy (BNCT)

    International Nuclear Information System (INIS)

    Heber, Elisa M.; Trivillin, Veronica A.; Itoiz, Maria E.; Rebagliati, J. Raul; Batistoni, Daniel; Kreimann, Erica L.; Schwint, Amanda E.; Nigg, David W.; Gonzalez, Beatriz N.

    2006-01-01

    BNCT is a tumor cell targeted radiation therapy. Inadequately boron targeted tumor populations jeopardize tumor control. Meeting the to date unresolved challenge of homogeneous targeting of heterogeneous tumors with effective boron carriers would contribute to therapeutic efficacy. The aim of the present study was to evaluate the degree of variation in boron content delivered by boronophenylalanine (BPA), GB-10 (Na 2 10 B 10 H 10 ) and the combined administration of (BPA+GB-10) in different portions of tumor, precancerous tissue around tumor and normal pouch tissue in the hamster cheek pouch oral cancer model. Boron content was evaluated by ICP-AES. The degree of homogeneity in boron targeting was assessed in terms of the coefficient of variation ([S.D./Mean]x100) of boron values. Statistical analysis of the results was performed by one-way ANOVA and the least significant difference test. GB-10 and GB-10 plus BPA achieved respectively a statistically significant 1.8-fold and 3.3-fold increase in targeting homogeneity over BPA. The combined boron compound administration protocol contributes to homogeneous targeting of heterogeneous tumors and would increase therapeutic efficacy of BNCT by exposing all tumor populations to neutron capture reactions in boron. (author)

  12. Current status of accelerator-based boron neutron capture therapy

    International Nuclear Information System (INIS)

    Kreiner, A. J.; Bergueiro, J.; Di Paolo, H.; Castell, W.; Vento, V. Thatar; Cartelli, D.; Kesque, J.M.; Valda, A.A.; Ilardo, J.C.; Baldo, M.; Erhardt, J.; Debray, M.E.; Somacal, H.R.; Estrada, L.; Sandin, J.C. Suarez; Igarzabal, M.; Huck, H.; Padulo, J.; Minsky, D.M.

    2011-01-01

    The direct use of proton and heavy ion beams for radiotherapy is a well established cancer treatment modality, which is becoming increasingly widespread due to its clear advantages over conventional photon-based treatments. This strategy is suitable when the tumor is spatially well localized. Also the use of neutrons has a long tradition. Here Boron Neutron Capture Therapy (BNCT) stands out, though on a much smaller scale, being a second-generation promising alternative for tumors which are diffuse and infiltrating. On this sector, so far only nuclear reactors have been used as neutron sources. In this paper we describe the current situation worldwide as far as the use of accelerator-based neutron sources for BNCT is concerned (so-called Accelerator-Based (AB)-BNCT). In particular we discuss the present status of an ongoing project to develop a folded Tandem-ElectroStatic-Quadrupole (TESQ) accelerator at the Atomic Energy Commission of Argentina. The project goal is a machine capable of delivering 30 mA of 2.4 MeV protons to be used in conjunction with a neutron production target based on the 7 Li(p,n) 7 Be reaction. These are the specifications needed to produce sufficiently intense and clean epithermal neutron beams to perform BNCT for deep-seated tumors in less than an hour. (author)

  13. Guide to Sources: American History, Anthropology, Folklore, Business Administration, Education, English, Food Science, French, German, Music, Philosophy, Political Science, Psychology, and Sociology.

    Science.gov (United States)

    Maine Univ., Orono. Raymond H. Fogler Library.

    This group of 13 library guides, designed to introduce the student to some of the bibliographical tools available in various subject areas at Fogler Library, is not intended to be a complete listing, but rather a selective introduction to the many sources of information available to the beginning researcher. Information is provided on the use of…

  14. The Aggregation of Boron on the Tissues of Gold Fish (Carassius auratus Linnaeus, 1758

    Directory of Open Access Journals (Sweden)

    Tuncer Okan Genç

    2015-03-01

    Full Text Available In this study, it was aimed to determine the water-borne and food-borne boron accumulation in the liver and muscle tissues of Gold Fish (Carassius auratus Linnaeus, 1758. For each treatment, 12 individuals were. The water-borne boron treatments were applied as boron acid concentration of 1 mg/L, 10 mg/L and 20 mg/L in the aquarium water, while the food-borne boron treatments were prepared food contained the defined levels of boron (1 mg/kg, 5 mg/kg and 10 mg/kg as boric acid. The boron levels in the tissues were determined by an ICP-MS procedure. The maximum boron concentration was found in the 20mg/L water borne boron treatment in the liver tissue (1.78±0.02 mg/kg. In the water-borne boron treatments, the maximum Transfer Factor (TF was found in the 20mg/L boron concentration, and TF values were increased when the boron concentrations were decreasing. In the 1 mg/kg food-borne boron treatment, TF was found as 0, and increasing concentration of boron in the food caused an increase in TF reached about 0.06. This study suggested that the target organ for boron accumulation is the liver rather than the muscles and the accumulation of food-borne boron is lower when comparing water-borne boron.

  15. Boron stress response and accumulation potential of the extremely tolerant species Puccinellia frigida

    International Nuclear Information System (INIS)

    Rámila, Consuelo d.P.; Contreras, Samuel A.; Di Domenico, Camila; Molina-Montenegro, Marco A.; Vega, Andrea; Handford, Michael; Bonilla, Carlos A.

    2016-01-01

    Highlights: • P. frigida presents an extremely high boron toxicity threshold. • Restricting uptake and internal tolerance mechanisms could confer boron tolerance. • P. frigida is a boron hyperaccumulator over a wide range of concentrations. • The species has potential for phytoremediation purposes. - Abstract: Phytoremediation is a promising technology to tackle boron toxicity, which restricts agricultural activities in many arid and semi-arid areas. Puccinellia frigida is a perennial grass that was reported to hyperaccumulate boron in extremely boron-contaminated sites. To further investigate its potential for phytoremediation, we determined its response to boron stress under controlled conditions (hydroponic culture). Also, as a first step towards understanding the mechanisms underlying its extreme tolerance, we evaluated the presence and expression of genes related with boron tolerance. We found that P. frigida grew normally even at highly toxic boron concentrations in the medium (500 mg/L), and within its tissues (>5000 mg/kg DW). We postulate that the strategies conferring this extreme tolerance involve both restricting boron accumulation and an internal tolerance mechanism; this is consistent with the identification of putative genes involved in both mechanisms, including the expression of a possible boron efflux transporter. We also found that P. frigida hyperaccumulated boron over a wide range of boron concentrations. We propose that P. frigida could be used for boron phytoremediation strategies in places with different soil characteristics and boron concentrations. Further studies should pave the way for the development of clean and low-cost solutions to boron toxicity problems.

  16. Exploiting the enantioselectivity of Baeyer-Villiger monooxygenases via boron oxidation

    NARCIS (Netherlands)

    Brondani, Patricia B.; Dudek, Hanna; Reis, Joel S.; Fraaije, Marco W.; Andrade, Leandro H.

    2012-01-01

    The enantioselective carbon-boron bond oxidation of several chiral boron-containing compounds by Baeyer-Villiger monooxygenases was evaluated. PAMO and M446G PAMO conveniently oxidized 1-phenylethyl boronate into the corresponding 1-(phenyl)ethanol (ee = 82-91%). Cyclopropyl boronic esters were also

  17. Study of the boron distribution in pea and alfalfa plants using SSNTD

    International Nuclear Information System (INIS)

    Li Jianming; Inst. for Application of Atomic Energy)" data-affiliation=" (Chinese Academy of Agricultural Sciences, Beijing, BJ (China)> Inst. for Application of Atomic Energy)" >Deng Hongmin

    1988-01-01

    The distribution of boron in pea (Pisum sativum L.) and alfalfa (Medicago sativa L.) was determined by using SSNTD. The results show that boron concentrations in leaves are highest, furthermore boron concentrations of the base leaves are higher than those of the top leaves. Among flower tissues, calyx has the highest boron concentration

  18. Boron stress response and accumulation potential of the extremely tolerant species Puccinellia frigida

    Energy Technology Data Exchange (ETDEWEB)

    Rámila, Consuelo d.P. [Departamento de Ingeniería Hidráulica y Ambiental, Pontificia Universidad Católica de Chile, Avenida Vicuña Mackenna 4860, 7820436 Santiago (Chile); Contreras, Samuel A.; Di Domenico, Camila [Facultad de Agronomía e Ingeniería Forestal, Pontificia Universidad Católica de Chile, Avenida Vicuña Mackenna 4860, 7820436 Santiago (Chile); Molina-Montenegro, Marco A. [Centro de Estudios Avanzados en Zonas Áridas (CEAZA), Facultad de Ciencias del Mar, Universidad Católica del Norte, Larrondo 1281, Coquimbo (Chile); Instituto de Ciencias Biológicas, Universidad de Talca, Avda. Lircay s/n, Talca (Chile); Vega, Andrea [Facultad de Agronomía e Ingeniería Forestal, Pontificia Universidad Católica de Chile, Avenida Vicuña Mackenna 4860, 7820436 Santiago (Chile); Handford, Michael [Departmento de Biología, Facultad de Ciencias, Universidad de Chile, Avenida Las Palmeras 3425, 7800024 Santiago (Chile); Bonilla, Carlos A. [Departamento de Ingeniería Hidráulica y Ambiental, Pontificia Universidad Católica de Chile, Avenida Vicuña Mackenna 4860, 7820436 Santiago (Chile); Centro de Desarrollo Urbano Sustentable (CEDEUS), Pontificia Universidad Católica de Chile, Avenida Vicuña Mackenna 4860, 7820436 Santiago (Chile); and others

    2016-11-05

    Highlights: • P. frigida presents an extremely high boron toxicity threshold. • Restricting uptake and internal tolerance mechanisms could confer boron tolerance. • P. frigida is a boron hyperaccumulator over a wide range of concentrations. • The species has potential for phytoremediation purposes. - Abstract: Phytoremediation is a promising technology to tackle boron toxicity, which restricts agricultural activities in many arid and semi-arid areas. Puccinellia frigida is a perennial grass that was reported to hyperaccumulate boron in extremely boron-contaminated sites. To further investigate its potential for phytoremediation, we determined its response to boron stress under controlled conditions (hydroponic culture). Also, as a first step towards understanding the mechanisms underlying its extreme tolerance, we evaluated the presence and expression of genes related with boron tolerance. We found that P. frigida grew normally even at highly toxic boron concentrations in the medium (500 mg/L), and within its tissues (>5000 mg/kg DW). We postulate that the strategies conferring this extreme tolerance involve both restricting boron accumulation and an internal tolerance mechanism; this is consistent with the identification of putative genes involved in both mechanisms, including the expression of a possible boron efflux transporter. We also found that P. frigida hyperaccumulated boron over a wide range of boron concentrations. We propose that P. frigida could be used for boron phytoremediation strategies in places with different soil characteristics and boron concentrations. Further studies should pave the way for the development of clean and low-cost solutions to boron toxicity problems.

  19. Entangled histories

    International Nuclear Information System (INIS)

    Cotler, Jordan; Wilczek, Frank

    2016-01-01

    We introduce quantum history states and their mathematical framework, thereby reinterpreting and extending the consistent histories approach to quantum theory. Through thought experiments, we demonstrate that our formalism allows us to analyze a quantum version of history in which we reconstruct the past by observations. In particular, we can pass from measurements to inferences about ‘what happened’ in a way that is sensible and free of paradox. Our framework allows for a richer understanding of the temporal structure of quantum theory, and we construct history states that embody peculiar, non-classical correlations in time. (paper)

  20. β-Rhombohedral Boron: At the Crossroads of the Chemistry of Boron and the Physics of Frustration [Boron: a frustrated element

    Energy Technology Data Exchange (ETDEWEB)

    Ogitsu, Tadashi [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Schwegler, Eric [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Galli, Giulia [Univ. of California, Davis, CA (United States)

    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.

  1. Lithium- and boron-bearing brines in the Central Andes: exploring hydrofacies on the eastern Puna plateau between 23° and 23°30'S

    Science.gov (United States)

    Steinmetz, R. L. López

    2017-01-01

    Internally drained basins of the Andean Plateau are lithium- and boron-bearing systems. The exploration of ionic facies and parental links in a playa lake located in the eastern Puna (23°-23°30'S) was assessed by hydrochemical determinations of residual brines, feed waters and solutions from weathered rocks. Residual brines have been characterized by the Cl- (SO4 =)/Na+ (K+) ratio. Residual brines from the playa lake contain up to 450 mg/l of boron and up to 125 mg/l of lithium, and the Las Burras River supplies the most concentrated boron (20 mg/l) and lithium (3.75 mg/l) inflows of the basin. The hydro-geochemical assessment allowed for the identification of three simultaneous sources of boron: (1) inflow originating from granitic areas of the Aguilar and Tusaquillas ranges; (2) weathering of the Ordovician basement; and (3) boron-rich water from the Las Burras River. Most of the lithium input of the basin is likely generated by present geothermal sources rather than by weathering and leaching of ignimbrites and plutonic rocks. However, XRD analyses of playa lake sediments revealed the presence of lithian micas of clastic origin, including taeniolite and eucriptite. This study is the first to document these rare Li-micas from the Puna basin. Thus, both residual brines and lithian micas contribute to the total Li content in the studied hydrologic system.

  2. Drug delivery system design and development for boron neutron capture therapy on cancer treatment

    International Nuclear Information System (INIS)

    Sherlock Huang, Lin-Chiang; Hsieh, Wen-Yuan; Chen, Jiun-Yu; Huang, Su-Chin; Chen, Jen-Kun; Hsu, Ming-Hua

    2014-01-01

    We have already synthesized a boron-containing polymeric micellar drug delivery system for boron neutron capture therapy (BNCT). The synthesized diblock copolymer, boron-terminated copolymers (Bpin-PLA-PEOz), consisted of biodegradable poly(D,L-lactide) (PLA) block and water-soluble polyelectrolyte poly(2-ethyl-2-oxazoline) (PEOz) block, and a cap of pinacol boronate ester (Bpin). In this study, we have demonstrated that synthesized Bpin-PLA-PEOz micelle has great potential to be boron drug delivery system with preliminary evaluation of biocompatibility and boron content. - Highlights: • Herein, we have synthesized boron-modified diblock copolymer. • Bpin-PLA-PEOz, which will be served as new boron containing vehicle for transporting the boron drug. • This boron containing Bpin-PLA-PEOz micelle was low toxicity can be applied to drug delivery

  3. Axial channeling of boron ions into silicon

    International Nuclear Information System (INIS)

    La Ferla, A.; Galvagno, G.; Raineri, V.; Setola, R.; Rimini, E.; Carnera, A.; Gasparotto, A.

    1992-01-01

    Channeling boron implants were performed into (100) and (110) silicon substrates in the energy range 80-700 keV. The dose ranged between 3.5x10 11 and 1x10 15 atoms/cm 2 . The axial channeling concentration profiles of implanted B + were compared with that obtained for incidence along the random direction of the crystal and with that obtained by implantation in amorphous silicon. The electrical and chemical boron distributions were obtained by spreading resistance and secondary ion mass spectrometry measurements, respectively. The inelastic stopping power, S c , was extracted from the experimental maximum ranges for the [100] and [110] axis. The energy dependence of the electronic stopping power is given by S e = KE p with p [100] = 0.469±0.010 and p [110] = 0.554±0.004. Simulations obtained by the MARLOWE code, using the Oen-Robinson impact parameter dependent formula, for the electronic energy loss reproduce quite well the experimental depth profiles. (orig.)

  4. Method for fabricating boron carbide articles

    International Nuclear Information System (INIS)

    Ardary, Z.; Reynolds, C.

    1980-01-01

    Described is a method for fabricating an essentially uniformly dense boron carbide article of a length-to-diameter or width ratio greater than 2 to 1 comprising the steps of providing a plurality of article segments to be joined together to form the article with each of said article segments having a length-to-diameter or width ratio less than 1.5 to 1. Each segment is fabricated by hot pressing a composition consisting of boron carbide powder at a pressure and temperature effective to provide the article segment with a density greater than about 85% of theoretical density, providing each article segment with parallel planar end surfaces, placing a plurality of said article segments in a hot-pressing die in a line with the planar surfaces of adjacent article segments being disposed in intimate contact, and hot pressing the aligned article segments at a temperature and pressure effective to provide said article with a density over the length thereof in the range of about 94 to 98 percent theoretical density and greater than the density provided in the discrete hot pressing of each of the article segments and to provide a bond between adjacent article segments with said bond being at least equivalent in hardness, strength and density to a remainder of said article

  5. Determination of boron spectrophotometry in thorium sulfate

    International Nuclear Information System (INIS)

    Federgrun, L.; Abrao, A.

    1976-01-01

    A procedure for the determination of microquantities of boron in nuclear grade thorium sulfate is described. The method is based on the extraction of BF - 4 ion associated to monomethylthionine (MMT) in 1,2 - dichloroethane. The extraction of the colored BF - 4 -MMT complex does not allow the presence of sulfuric and phosphoric acids; other anions interfere seriously. This fact makes the dissolution of the thorium sulfate impracticable, since it is insoluble in both acids. On the other hand, the quantitative separation of thorium is mandatory, to avoid the precipitation of ThF 4 . To overcome this difficulty, the thorium sulfate is dissolved using a strong cationic ion exchanger, Th 4+ being totally retained into the resin. Boron is then analysed in the effluent. The procedure allows the determination of 0.2 to 10.0 microgramas of B, with a maximum error of 10%. Thorium sulfate samples with contents of 0.2 to 2.0μg B/gTh have being analysed [pt

  6. Microdosimetry for Boron Neutron Capture Therapy

    International Nuclear Information System (INIS)

    Maughan, R.L.; Kota, C.

    2000-01-01

    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

  7. Intellectual History

    DEFF Research Database (Denmark)

    In the 5 Questions book series, this volume presents a range of leading scholars in Intellectual History and the History of Ideas through their answers to a brief questionnaire. Respondents include Michael Friedman, Jacques le Goff, Hans Ulrich Gumbrecht, Jonathan Israel, Phiip Pettit, John Pocock...

  8. Synovectomy by neutron capture in boron; Sinovectomia por captura de neutrones en boro

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H.R. [Unidades Academicas de Estudios Nucleares, Ingenieria Electrica y Matematicas, Universidad Autonoma de Zacatecas, A.P. 336, C.P. 98000 Zacatecas (Mexico)

    2002-07-01

    The rheumatoid arthritis is an illness which affect approximately at 3% of the World population. This illness is characterized by the inflammation of the joints which reduces the quality of life and the productivity of the patients. Since, it is an autoimmune illness, the inflammation is due to the overproduction of synovial liquid by the increase in the quantity of synoviocytes. The rheumatoid arthritis does not have a definitive recovery and the patients have three options of treatment: the use of drugs, the surgery and the radio synovectomy. The synovectomy by neutron capture in Boron is a novel proposal of treatment of the rheumatoid arthritis that consists in using a charged compound with Boron 10 that is preferently incorporated in the synoviocytes and to a less extent in the rest of surrounding tissues of the joint. Then, the joint is exposed to a thermal neutron field that induces the reaction (n, {alpha}) in the {sup 10} B. the products of this reaction place their energy inside synoviocytes producing their reduction and therefore the reduction of the joint inflammation. Since it is a novel procedure, the synovectomy by neutron capture in boron has two problems: the source design and the design of the adequate drug. In this work it has been realized a Monte Carlo study with the purpose to design a moderating medium that with a {sup 239} Pu Be source in its center, produces a thermal neutron field. With the produced neutron spectra, the neutrons spectra and neutron doses were calculated in different sites inside a model of knee joint. In Monte Carlo studies it is necessary to know the elemental composition of all the joint components, for the case of synovia and the synovial liquid this information does not exist in such way that it is supposed that its composition is equal than the water. In this work also it has been calculated the kerma factors by neutrons of synovia and the synovial liquid supposing that their elemental composition are similar to the

  9. Flame-photometric determination of boron in alloys with chromatographic separation

    International Nuclear Information System (INIS)

    Telegin, G.F.; Popandopulo, Yu.I.; Grazhuiene, S.S.

    1983-01-01

    A study was made on the possibility of using flame-photometric method for boron determination in iron base alloys. The method of extraction chromatography was used for boron separation from iron. It is possible to reliably determine boron in Fesub(x)Bsub(100-x) alloys only at a concentration ratio of iron to boron <=0.2. The technique for determination of boron in Fesub(x)Bsub(100-x) alloys was developed on the base of the conducted investigation

  10. Flame-photometric determination of boron in alloys with chromatographic separation

    Energy Technology Data Exchange (ETDEWEB)

    Telegin, G.F.; Popandopulo, Yu.I.; Grazhuiene, S.S. (AN SSSR, Chernogolovka. Inst. Fiziki Tverdogo Tela)

    1983-01-01

    A study was made on the possibility of using flame-photometric method for boron determination in iron base alloys. The method of extraction chromatography was used for boron separation from iron. It is possible to reliably determine boron in Fesub(x)Bsub(100-x) alloys only at a concentration ratio of iron to boron <=0.2. The technique for determination of boron in Fesub(x)Bsub(100-x) alloys was developed on the base of the conducted investigation.

  11. SHB1/HY1 Alleviates Excess Boron Stress by Increasing BOR4 Expression Level and Maintaining Boron Homeostasis in Arabidopsis Roots

    Directory of Open Access Journals (Sweden)

    Qiang Lv

    2017-05-01

    Full Text Available Boron is an essential mineral nutrient for higher plant growth and development. However, excessive amounts of boron can be toxic. Here, we report on the characterization of an Arabidopsis mutant, shb1 (sensitive to high-level of boron 1, which exhibits hypersensitivity to excessive boron in roots. Positional cloning demonstrated that the shb1 mutant bears a point mutation in a gene encoding a heme oxygenase 1 (HO1 corresponding to the HY1 gene involved in photomorphogenesis. The transcription level of the SHB1/HY1 gene in roots is up-regulated under excessive boron stimulation. Either overexpressing SHB1/HY1 or applying the HO1 inducer hematin reduces boron accumulation in roots and confers high boron tolerance. Furthermore, carbon monoxide and bilirubin, catalytic products of HO1, partially rescue the boron toxicity-induced inhibition of primary root growth in shb1. Additionally, the mRNA level of BOR4, a boron efflux transporter, is reduced in shb1 roots with high levels of boron supplementation, and hematin cannot relieve the boron toxicity-induced root inhibition in bor4 mutants. Taken together, our study reveals that HO1 acts via its catalytic by-products to promote tolerance of excessive boron by up-regulating the transcription of the BOR4 gene and therefore promoting the exclusion of excessive boron in root cells.

  12. Modeling of interstitial diffusion of ion-implanted boron

    International Nuclear Information System (INIS)

    Velichko, O.I.; Knyazheva, N.V.

    2009-01-01

    A model of the interstitial diffusion of ion-implanted boron during rapid thermal annealing of silicon layers previously amorphized by implantation of germanium has been proposed. It is supposed that the boron interstitials are created continuously during annealing due to generation, dissolution, or rearrangement of the clusters of impurity atoms which are formed in the ion-implanted layers with impurity concentration above the solubility limit. The local elastic stresses arising due to the difference of boron atomic radius and atomic radius of silicon also contribute to the generation of boron interstitials. A simulation of boron redistribution during thermal annealing for 60 s at a temperature of 850 C has been carried out. The calculated profile agrees well with the experimental data. A number of the parameters of interstitial diffusion have been derived. In particular, the average migration length of nonequilibrium boron interstitials is equal to 12 nm. It was also obtained that approximately 1.94% of boron atoms were converted to the interstitial sites, participated in the fast interstitial migration, and then became immobile again transferring into a substitutional position or forming the electrically inactive complexes with crystal lattice defects. (authors)

  13. Influence of boron reduction strategies on PWR accident management flexibility

    International Nuclear Information System (INIS)

    Papukchiev, Angel Aleksandrov; Liu, Yubo; Schaefer, Anselm

    2007-01-01

    In conventional pressurized water reactor (PWR) designs, soluble boron is used for reactivity control over core fuel cycle. Design changes to reduce boron concentration in the reactor coolant are of general interest regarding three aspects - improved reactivity feedback properties, lower impact of boron dilution scenarios on PWR safety and eventually more flexible accident management procedures. In order to assess the potential advantages through the introduction of boron reduction strategies in current PWRs, two low boron core configurations based on fuel with increased utilization of gadolinium and erbium burnable absorbers have been developed. The new PWR designs permit to reduce the natural boron concentration in reactor coolant at begin of cycle to 518 ppm and 805 ppm. For the assessment of the potential safety advantages of these cores a hypothetical beyond design basis accident has been simulated with the system code ATHLET. The analyses showed improved inherent safety and increased accident management flexibility of the low boron cores in comparison with the standard PWR. (author)

  14. Boron neutron capture therapy for malignant melanoma: An experimental approach

    Energy Technology Data Exchange (ETDEWEB)

    Larsson, B.S.; Larsson, B.; Roberto, A. (Uppsala Univ. (Sweden))

    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.

  15. Current status of boron neutron capture therapy of high grade gliomas and recurrent head and neck cancer

    Directory of Open Access Journals (Sweden)

    Barth Rolf F

    2012-08-01

    Full Text Available Abstract Boron neutron capture therapy (BNCT is a biochemically targeted radiotherapy based on the nuclear capture and fission reactions that occur when non-radioactive boron-10, which is a constituent of natural elemental boron, is irradiated with low energy thermal neutrons to yield high linear energy transfer alpha particles and recoiling lithium-7 nuclei. Clinical interest in BNCT has focused primarily on the treatment of high grade gliomas, recurrent cancers of the head and neck region and either primary or metastatic melanoma. Neutron sources for BNCT currently have been limited to specially modified nuclear reactors, which are or until the recent Japanese natural disaster, were available in Japan, United States, Finland and several other European countries, Argentina and Taiwan. Accelerators producing epithermal neutron beams also could be used for BNCT and these are being developed in several countries. It is anticipated that the first Japanese accelerator will be available for therapeutic use in 2013. The major hurdle for the design and synthesis of boron delivery agents has been the requirement for selective tumor targeting to achieve boron concentrations in the range of 20 μg/g. This would be sufficient to deliver therapeutic doses of radiation with minimal normal tissue toxicity. Two boron drugs have been used clinically, a dihydroxyboryl derivative of phenylalanine, referred to as boronophenylalanine or “BPA”, and sodium borocaptate or “BSH” (Na2B12H11SH. In this report we will provide an overview of other boron delivery agents that currently are under evaluation, neutron sources in use or under development for BNCT, clinical dosimetry, treatment planning, and finally a summary of previous and on-going clinical studies for high grade gliomas and recurrent tumors of the head and neck region. Promising results have been obtained with both groups of patients but these outcomes must be more rigorously evaluated in larger

  16. Influence of boronization on operation with high-Z plasma facing components in Alcator C-Mod

    International Nuclear Information System (INIS)

    Lipschultz, B.; Lin, Y.; Marmar, E.S.; Whyte, D.G.; Wukitch, S.; Hutchinson, I.H.; Irby, J.; LaBombard, B.; Reinke, M.L.; Terry, J.L.; Wright, G.

    2007-01-01

    We report the results of operation of Alcator C-Mod with all high-Z molybdenum plasma facing component (PFC) surfaces. Without boron-coated PFCs energy confinement was poor (H ITER,89 ∼ 1) due to high core molybdenum (n Mo /n e ≤ 0.1%) and radiation. After applying boron coatings, n Mo /n e was reduced by a factor of 10-20 with H ITER,89 approaching 2. Results of between-discharge boronization, localized at various major radii, point towards important molybdenum source regions being small, outside the divertor, and due to RF-sheath-rectification. Boronization also has a significant effect on the plasma startup phase lowering Z eff , radiation, and lowering the runaway electron damage. The requirement of low-Z coatings over at least a fraction of the Mo PFCs in C-Mod for best performance together with the larger than expected D retention in Mo, give impetus for further high-Z PFC investigations to better predict the performance of un-coated tungsten surfaces in ITER and beyond

  17. Radiometric analyzer for boron content determination in glass and silicon containing compounds

    International Nuclear Information System (INIS)

    Irmer, K.

    1979-01-01

    A radiometric analyzer is described working on the principle of the thermal neutrons transfere. The device consists of two units: of the measuring gage into which the samples to be measured, are introduced; and of the measuring disk where the sygnals from the gage are processed. The measuring gage consists of the isotopic neutron source having the neutrons yield of 10 7 neutron/sec; BE 3 - scintillation counter and shield. The sample measured has a shape of cylinder and surrounds the counter. The neutron source is located in the paraffin moderator. The moderator with the neutron source in it, is rotating around a sample measured and, due to the rotation of the neutron source, uniform average neutron flux in the sample is obtained. Effective length of the proportional counter is limited by the cadmium neutron absorbers. Due to such design of the analyzer, unevenness of the radiation level of the sample measured do not affect measurement accuracy. The thermal neutrons transfer affects through the neutros capture by boron atoms and elastic interaction with the hydrogen atoms nuclei. Influence of hydrogen can be taken into account if the chemical composition of the boron containing compound is known. Due to simplicity, the device described is handy for industrial application. In the industrial conditions the device is repaid after 4 years of continious exploitation. Accuracy of measurements by this device is of 0.05% with time of measurement up to one minute [ru

  18. Boron-Based Hydrogen Storage: Ternary Borides and Beyond

    Energy Technology Data Exchange (ETDEWEB)

    Vajo, John J. [HRL Laboratories, LLC, Malibu, CA (United States)

    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.

  19. Structure and single-phase regime of boron carbides

    International Nuclear Information System (INIS)

    Emin, D.

    1988-01-01

    The boron carbides are composed of twelve-atom icosahedral clusters which are linked by direct covalent bonds and through three-atom intericosahedral chains. The boron carbides are known to exist as a single phase with carbon concentrations from about 8 to about 20 at. %. This range of carbon concentrations is made possible by the substitution of boron and carbon atoms for one another within both the icosahedra and intericosahedral chains. The most widely accepted structural model for B 4 C (the boron carbide with nominally 20% carbon) has B/sub 11/C icosahedra with C-B-C intericosahedral chains. Here, the free energy of the boron carbides is studied as a function of carbon concentration by considering the effects of replacing carbon atoms within B 4 C with boron atoms. It is concluded that entropic and energetic considerations both favor the replacement of carbon atoms with boron atoms within the intericosahedral chains, C-B-C→C-B-B. Once the carbon concentration is so low that the vast majority of the chains are C-B-B chains, near B/sub 13/C 2 , subsequent substitutions of carbon atoms with boron atoms occur within the icosahedra, B/sub 11/C→B/sub 12/. Maxima of the free energy occur at the most ordered compositions: B 4 C,B/sub 13/C 2 ,B/sub 14/C. This structural model, determined by studying the free energy, agrees with that previously suggested by analysis of electronic and thermal transport data. These considerations also provide an explanation for the wide single-phase regime found for boron carbides

  20. Bengal Literature and History.

    Science.gov (United States)

    Dimock, Edward C., Jr., Ed.

    The unifying theme of the papers in this book is the use of creative literature as source material for the study of cultural history. Titles and authors of the papers are: "Encounter and Growth in Bengali Literature, A Survey of Medieval Bengali Literature" by T.W. Clark; "The Hindu Chiefdom in Middle Bengali Literature" by…

  1. Observing Children Learning History.

    Science.gov (United States)

    Blake, David W.

    1981-01-01

    Compares the suitability of two kinds of history curricula for the varying levels of cognitive development of 9- to 11-year-olds. Fifteen British students studied the Victorian Era using transcripts of original documents, while 15 classmates used standard textbooks. The documents seemed to give students greater awareness of the evidence sources.…

  2. No evidence that boron influences tree species distributions in lowland tropical forests of Panama.

    Science.gov (United States)

    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. No claim to original US government works New Phytologist © 2016 New Phytologist Trust.

  3. Are Arctic productivity hotspots sources or sinks? A trait-based approach to mesozooplankton life history and energetics along advective corridors

    DEFF Research Database (Denmark)

    Banas, Neil; Ashjian, Carin J.; Campbell, Robert G.

    Marine productivity hotspots are usually conceived of, or defined as, sources of energy and nutrients to surrounding waters (for example, in the context of marine protected areas that serve as buffers against fisheries catch elsewhere). This study considers whether Arctic hotspots for top predators...... to mesozooplankton and where it is transferred from mesozooplankton to higher predators. These results suggest that the yield of Calanus to predators in the Chukchi Sea is dependent primarily on Bering Sea phytoplankton blooms, although this complex interdependence could change as ice retreats and phytoplankton...

  4. Reload safety evaluation of boron dilution accident related to shutdown margin proportional to boron concentration

    International Nuclear Information System (INIS)

    Zee, Sung Kyun; Lee, Ki Bog; Song, Jae Woong

    1993-06-01

    This report investigates the efficient safety evaluation method and analysis procedure on Boron Dilution Accident(BDA) under the proportional shutdown margin to boron concentration. Also investigated are problems caused by applying this shutdown margin limit. Through this investigation, the safety of Kori-3 Cycle-8, Yonggwang-2 Cycle-7, Kori-4 Cycle-8 and Yonggwang-1 Cycle-8 with respect to BDA is verified. In order to satisfy the shutdown margin requirement in the Technical Specifications, it is shown that the High Flux Alarm at Shutdown Setting for Kori-4 Cycle-8 and Yonggwang-1 Cycle-8 at Mode 5 should be set at 2 or the Technical Specification should be revised. (Author)

  5. Thermoelectric properties of β-boron and some boron compounds. Final report, August 1981-September 1984

    International Nuclear Information System (INIS)

    Slack, G.A.; Rosolowski, J.H.; Miller, M.L.; Huseby, I.C.

    1984-12-01

    The thermoelectric properties, that is the Seebeck coefficient, and electrical and thermal conductivity, of doped β-boron have been measured from 300 to 1600 K. Most of the useful doping elements are transition metals and occupy interstitial sites in the lattice. The highest figure of merit so far achieved at 1000 K is ZT = 0.11 for P-type, polycrystalline, hot-pressed β-boron doped with copper. Higher values may be achievable once a better P-type dopant is found. Some experiments on B 68 Y, α-B 12 Al, B 4 C, and B 6 Si are described. Transition metals appear to be effective dopants for B 68 Y and B 4 C

  6. Dose modification factors in boron neutron capture therapy

    Energy Technology Data Exchange (ETDEWEB)

    Allen, B.J. (Australian Nuclear Science and Technology Organization (ANSTO), Menai (Australia))

    1993-01-01

    The effective treatment depth and therapeutic ratio in boron neutron capture therapy (BNCT) depend on a number of macroscopic dose factors such as boron concentrations in the tumor, normal tissue and blood. However, the role of various microscopic dose modification factors can be of critical importance in the evaluation of normal tissue tolerance levels. An understanding of these factors is valuable in designing BNCT experiments and the selection of appropriate boron compounds. These factors are defined in this paper and applied to the case of brain tumors with particular attention to capillary endothelial cells and oligodendrocytes. (orig.).

  7. Photometric and emission-spectrometric determination of boron in steels

    International Nuclear Information System (INIS)

    Thierig, D.

    1982-01-01

    A method for the photometric determination of boron in unalloyed and alloyed steels is described, in which Curcumine is used as reagent. A separation of boron is not necessary. Limit of detection: 0.0003% B. The decomposition of boron nitride in the steel is achieved by heating the whole sample in fuming sulphuric acid/phosphoric acid. For the emission spectrometric investigation of solid steel samples and for the spectrochemical analysis of solutions with plasma excitation working parameters are given and possibilities of interferences are demonstrated. (orig.) [de

  8. On Certain Topological Indices of Boron Triangular Nanotubes

    Science.gov (United States)

    Aslam, Adnan; Ahmad, Safyan; Gao, Wei

    2017-08-01

    The topological index gives information about the whole structure of a chemical graph, especially degree-based topological indices that are very useful. Boron triangular nanotubes are now replacing usual carbon nanotubes due to their excellent properties. We have computed general Randić (Rα), first Zagreb (M1) and second Zagreb (M2), atom-bond connectivity (ABC), and geometric-arithmetic (GA) indices of boron triangular nanotubes. Also, we have computed the fourth version of atom-bond connectivity (ABC4) and the fifth version of geometric-arithmetic (GA5) indices of boron triangular nanotubes.

  9. Ultrastructural changes in tumor cells following boron neutron capture therapy

    International Nuclear Information System (INIS)

    Barkla, D.H.; Brown, J.K.; Meriaty, H.; Allen, B.J.

    1992-01-01

    In a previous study the authors reported on morphological changes in two human melanoma cell lines treated with 10 B-phenylalanine(BPA) and Boron Neutron Capture Therapy(BNCT). The present study describes morphological changes in melanoma and glioma cell lines treated with boron-tetraphenyl porphyrin(BTPP) and BNCT. Porphyrin compounds are selectively taken up by tumor cells and have been used clinically in phototherapy treatment of cancer patients. Boronated porphyrins show good potential as therapeutic agents in BNCT treatment of human cancer patients

  10. Electrophoretic deposition of boron-10 in neutron detectors electrodes

    International Nuclear Information System (INIS)

    Oliveira Sampa, M.H. de; Vinhas, L.A.; Vieira, J.M.

    1990-01-01

    Process of boron-10 electrophoresis on large area of aluminum substrates was developed with the aim of using them in the construction of neutron detectors. After definition and optimization of the boron electrophoresis parameters, depositions of boron-10 on aluminum cylinders were performed and used as electrodes in gamma compensated and non-compensated ionization chambers and in proportional detectors. These prototypes were designed and builded at IPEN-CNEN-SP, and submited for characterization tests at IEA-R1 reactor, and they fulfil the technical specifications of the project. (author) [pt

  11. On certain topological indices of boron triangular nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Aslam, Adnan [Univ. of Engineering and Technology, Lahore (Pakistan). Dept. of Natural Sciences and Humanities; Ahmad, Safyan [GC Univ. Lahore (Pakistan). Abdus Salam School of Mathematical Sciences; Gao, Wei [Yunnan Normal Univ., Kunming (China). School of Information Science and Technology

    2017-11-01

    The topological index gives information about the whole structure of a chemical graph, especially degree-based topological indices that are very useful. Boron triangular nanotubes are now replacing usual carbon nanotubes due to their excellent properties. We have computed general Randic (R{sub a}), first Zagreb (M{sub 1}) and second Zagreb (M{sub 2}), atom-bond connectivity (ABC), and geometric-arithmetic (GA) indices of boron triangular nanotubes. Also, we have computed the fourth version of atom-bond connectivity (ABC{sub 4}) and the fifth version of geometric-arithmetic (GA{sub 5}) indices of boron triangular nanotubes.

  12. Boron complexing with H-resorcinol and acidic hydroxyxanthene dyes

    International Nuclear Information System (INIS)

    Nazarenko, V.A.; Flyantikova, G.V.; Chekirda, T.N.

    1984-01-01

    Complex formation of boron with H-resorcinol (hr; 2,4-dihydroxybenzene-azo -8-hydroxynaphtalene-3,6-disulfonic acid) and acidic hydroxyxanthene dyes (hxd: fluorescein, eosine, erathrosine). Mixed-ligand complexes with a ratio of r:hr:hxd=1:1:1 are formed at pH=5-6. The chemism of the complex formation of boron with H-resorcinol and fluorescein has been studied. The stability consta nt of the complex is 1.12x10 21 , the conditional molar absorptivitis 1.80x10 0 . This complex formation reaction was used for photometric determination of boron in natural water

  13. Coordination Networks Based on Boronate and Benzoxaborolate Ligands

    Directory of Open Access Journals (Sweden)

    Saad Sene

    2016-05-01

    Full Text Available Despite the extensive range of investigations on boronic acids (R-B(OH2, some aspects of their reactivity still need to be explored. This is the case for the coordination chemistry of boronate anions (R-B(OH3−, which has only recently been started to be studied. The purpose of this review is to summarize some of the key features of boronate ligands (and of their cyclic derivatives, benzoxaborolates in materials: (i coordination properties; (ii spectroscopic signatures; and (iii emerging applications.

  14. Kinetics of chemical vapor deposition of boron on molybdenum

    International Nuclear Information System (INIS)

    Tanaka, W.; Nakaanishi, N.; Kato, E.

    1987-01-01

    Experimental rate data of chemical vapor deposition of boron by reduction of boron trichloride with hydrogen are analyzed to determine the reaction mechanism. The reaction orders with respect to the partial pressures of hydrogen and boron trichloride are one half and one third, respectively. It has been found that the outer layer of a deposited film is Mo/sub 2/B/sub 5/ and the inner layer is MoB by the use of X-ray diffraction and EPMA line analysis

  15. Boron-doped nanodiamonds as possible agents for local hyperthermia

    Science.gov (United States)

    Vervald, A. M.; Burikov, S. A.; Vlasov, I. I.; Ekimov, E. A.; Shenderova, O. A.; Dolenko, T. A.

    2017-04-01

    In this work, the effective heating of surrounding water by heavily-boron-doped nanodiamonds (NDs) under laser irradiation of visible wavelength was found. Using Raman scattering spectroscopy of aqueous suspensions of boron-doped NDs, it was found that this abnormally high heating results in the weakening of hydrogen bonds much more so (2-5 times stronger) than for undoped NDs. The property of boron-doped NDs to heat a solvent under the influence of laser radiation (1-5 W cm-2) opens broad prospects for their use to create nanoagents for medical oncology and local hyperthermia.

  16. Interlayer shear of nanomaterials: Graphene-graphene, boron nitride-boron nitride and graphene-boron nitride

    Institute of Scientific and Technical Information of China (English)

    Yinfeng Li; Weiwei Zhang; Bill Guo; Dibakar Datta

    2017-01-01

    In this paper,the interlayer sliding between graphene and boron nitride (h-BN) is studied by molecular dynamics simulations.The interlayer shear force between h-BN/h-BN is found to be six times higher than that of graphene/graphene,while the interlayer shear between graphene/h-BN is approximate to that of graphene/graphene.The graphene/h-BN heterostructure shows several anomalous interlayer shear characteristics compared to its bilayer counterparts.For graphene/graphene and h-BN/h-BN,interlayer shears only exit along the sliding direction while interlayer shear for graphene/h-BN is observed along both the translocation and perpendicular directions.Our results provide significant insight into the interlayer shear characteristics of 2D nanomaterials.

  17. THE BORON-TO-CARBON ABUNDANCE RATIO AND GALACTIC PROPAGATION OF COSMIC RADIATION

    International Nuclear Information System (INIS)

    Obermeier, A.; Boyle, P.; Müller, D.; Hörandel, J.

    2012-01-01

    In two long-duration balloon flights in 2003 and 2006, the TRACER cosmic-ray detector has measured the energy spectra and the absolute intensities of the cosmic-ray nuclei from boron (Z = 5) to iron (Z = 26) up to very high energies. In particular, the second flight has led to results on the energy spectrum of the secondary boron nuclei, and on the boron abundance relative to that of the heavier primary parent nuclei, commonly quantified as the 'B/C abundance ratio'. The energy dependence of this ratio, now available up to about 2 TeV amu –1 , provides a measure for the energy dependence of cosmic-ray propagation through the Galaxy, and for the shape of the cosmic-ray source energy spectrum. We use a Leaky-Box approximation of cosmic-ray propagation to obtain constraints on the relevant parameters on the basis of the results of TRACER and of other measurements. This analysis suggests that the source energy spectrum is a relatively soft power law in energy E –α , with spectral exponent α = 2.37 ± 0.12, and that the propagation path length Λ(E) is described by a power law in energy with exponent δ = 0.53 ± 0.06, but may assume a constant residual value Λ 0 at high energy. The value of Λ 0 is not well constrained but should be less than about 0.8 g cm –2 . Finally, we compare the data with numerical solutions of a diffusive reacceleration model, which also indicates a soft source spectrum.

  18. Proceedings of workshop on 'boron chemistry and boron neutron capture therapy'

    International Nuclear Information System (INIS)

    Kitaoka, Yoshinori

    1993-09-01

    This volume contains the proceedings of the 5th Workshop on 'the Boron Chemistry and Boron Neutron Capture Therapy' held on February 22 in 1993. The solubility of the boron carrier play an important role in the BNCT. New water-soluble p-boronophenylalanine derivatives are synthesized and their biological activities are investigated (Chap. 2 and 3). Some chemical problems on the BNCT were discussed, and the complex formation reaction of hydroxylboryl compounds were studied by the paper electrophoresis (Chap. 4). The results of the medical investigation on the BNCT using BSH compounds are shown in Chap. 5. Syntheses of o- and m-boronophenylalanine were done and their optical resolution was tried (Chap. 6). The complex formation reaction of p-boronophenylalanine (BPA) with L-DOPA and the oxidation reaction of the analogs are found in Chap. 7. The pka of BPA were determined by the isotachophoresis (Chap. 8). The chemical nature of dihydroxyboryl compounds were investigated by an infrared spectroscopy and electrophoresis (Chap. 9). New synthetic methods of BPA and p-boronophenylserine using ester of isocyanoacetic acid are described in Chap. 10. The induction of chromosomal aberations by neutron capture reaction are discussed from a point of the biological view. The a of the presented papers are indexed individually. (J.P.N.)

  19. The optical properties of boron carbide near boron K-edge inside periodical multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Ksenzov, Dmitriy; Schlemper, Christoph; Pietsch, Ullrich [University of Siegen (Germany)

    2010-07-01

    Multilayer mirrors made for the use in the wavelength range near K-edge of boron (188 eV) are of great interest for X-ray fluorescence analysis of boron content in doped semiconductors, plasma diagnostics, astronomy and lithography. Moreover, multilayer mirrors composed by a metal and a low Z element like boron are used as optical elements in both the soft x-ray spectral range as well as at higher photon energies on 3rd generation synchrotron beamlines. Using an energy-resolved photon-in-photon-out method we reconstructed the optical data from energy dependence of both integrated peak intensity and FWHM of the 1st order ML Bragg peak measured at the UHV triple axis soft-x-ray reflectometer at BESSY II. The experiments clearly demonstrate that the peak shape of the ML Bragg peak is most sensitive to any kind of electronic excitation and recombination in solid. The soft-ray reflectivity can give detailed information for MLs with thickness up to several tens of nanometers. In addition, measurements close to a resonance edge probe the chemical state of the respective constituent accompanied with a high sensitivity of changes close to the sample surface.

  20. An empirical model for parameters affecting energy consumption in boron removal from boron-containing wastewaters by electrocoagulation

    International Nuclear Information System (INIS)

    Yilmaz, A. Erdem; Boncukcuoglu, Recep; Kocakerim, M. Muhtar

    2007-01-01

    In this study, it was investigated parameters affecting energy consumption in boron removal from boron containing wastewaters prepared synthetically, via electrocoagulation method. The solution pH, initial boron concentration, dose of supporting electrolyte, current density and temperature of solution were selected as experimental parameters affecting energy consumption. The obtained experimental results showed that boron removal efficiency reached up to 99% under optimum conditions, in which solution pH was 8.0, current density 6.0mA/cm 2 , initial boron concentration 100mg/L and solution temperature 293K. The current density was an important parameter affecting energy consumption too. High current density applied to electrocoagulation cell increased energy consumption. Increasing solution temperature caused to decrease energy consumption that high temperature decreased potential applied under constant current density. That increasing initial boron concentration and dose of supporting electrolyte caused to increase specific conductivity of solution decreased energy consumption. As a result, it was seen that energy consumption for boron removal via electrocoagulation method could be minimized at optimum conditions. An empirical model was predicted by statistically. Experimentally obtained values were fitted with values predicted from empirical model being as following;[ECB]=7.6x10 6 x[OH] 0.11 x[CD] 0.62 x[IBC] -0.57 x[DSE] -0.04 x[T] -2.98 x[t] Unfortunately, the conditions obtained for optimum boron removal were not the conditions obtained for minimum energy consumption. It was determined that support electrolyte must be used for increase boron removal and decrease electrical energy consumption.