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Sample records for absolute boron concentration

  1. 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

  2. Nuclear Design Study for Reduced Boron Concentration Operation

    International Nuclear Information System (INIS)

    Daing, Aung Tharn; Kim, Myung Hyun

    2008-01-01

    In PWR, Boron Dilution Accident (BDA) which is an inadvertent reduction of the soluble boron concentration in the primary coolant, can lead to a positive reactivity insertion and a power increase. In this study, an optimal Low Boron Concentration (LBC) core design will be developed by reducing an excess reactivity so as to possess passive inherently safety features as well as one of attentively preventive measures of BDA scenarios. The scope of the research project concerning the change of operational procedure in chemical shim system, will involve three main parts namely, nuclear design for LBC core, feasibility check on the proposed core in safety and costs, and PSA approach on design change benefits. In addition, successful system analysis of the reactivity effects due to boron dilution transients, require a full coupling between core thermal hydraulic, reactor dynamics, and the use of Computational Fluid Dynamics (CFD) codes

  3. Nuclear Design Study for Reduced Boron Concentration Operation

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-10-15

    In PWR, Boron Dilution Accident (BDA) which is an inadvertent reduction of the soluble boron concentration in the primary coolant, can lead to a positive reactivity insertion and a power increase. In this study, an optimal Low Boron Concentration (LBC) core design will be developed by reducing an excess reactivity so as to possess passive inherently safety features as well as one of attentively preventive measures of BDA scenarios. The scope of the research project concerning the change of operational procedure in chemical shim system, will involve three main parts namely, nuclear design for LBC core, feasibility check on the proposed core in safety and costs, and PSA approach on design change benefits. In addition, successful system analysis of the reactivity effects due to boron dilution transients, require a full coupling between core thermal hydraulic, reactor dynamics, and the use of Computational Fluid Dynamics (CFD) codes.

  4. Variation of boron concentration in metallic glass ribbons

    International Nuclear Information System (INIS)

    Nagy, A.Z.; Vasvari, B.; Bakos, L.; Duwez, P.; Bogancs, J.; Nazarov, V.M.

    1980-01-01

    The boron concentration of Fe 40 Ni 40 P 14 B 6 , Fe 32 Ni 36 Cr 14 P 12 B 6 and Fe 40 Ni 40 B 20 metallic glasses is measured by neutron activation analysis on both surfaces of the ribbon samples. It is found that the boron concentration is always higher on the bright side of the ribbon than that on the dull side which is in contact with the cold surface of the wheel during the rapid quenching from the melt. A possible explanation is given in terms of the solid-liquid interface moving rapidly from the cooled surface to the free surface when preparing the samples. (author)

  5. Concentrations of boron, molybdenum, and selenium in chinook salmon

    Science.gov (United States)

    Hamilton, Steven J.; Wiedmeyer, Raymond H.

    1990-01-01

    The concentrations of boron, molybdenum, and selenium in young chinook salmon Oncorhynchus tshawytscha were determined in three partial life cycle chronic toxicity studies. In each study, fish were exposed to a mixture of boron, molybdenum, selenate, and selenite in the proportions found in subsurface agricultural drainage water in the basin of the San Joaquin Valley, California. Tests were conducted in well water and in site-specific fresh and brackish waters. No boron or molybdenum was detected in fish exposed to concentrations as high as 6,046 μg boron/L and 193 μg molybdenum/L for 90 d in well water or fresh water; however, whole-body concentrations of selenium increased with increasing exposure concentrations in well water and fresh water, but not in brackish water. Concentrations of selenium in chinook salmon were strongly correlated with reduced survival and growth of fish in well water and with reduced survival in a 15-d seawater challenge test of fish from fresh water. Concentrations of selenium in fish seemed to reach a steady state after 60 d of exposure in well water or fresh water. Fish in brackish water had only background concentrations of selenium after 60 d of exposure, and no effects on survival and growth in brackish water or on survival in a 10-d seawater challenge test were exhibited. This lack of effect in brackish water was attributed to initiation of the study with advanced fry, which were apparently better able to metabolize the trace element mixture than were the younger fish used in studies with well water and fresh water. In all three experimental waters, concentration factors (whole-body concentration/waterborne concentration) for selenium decreased with increasing exposure concentrations, suggesting decreased uptake or increased excretion, or both, of selenium at the higher concentrations.

  6. Variation of boron concentration in metallic glass ribbons

    International Nuclear Information System (INIS)

    Nagy, A.Z.; Vasvari, B.; Duwez, P.; Bakos, L.; Seres, Z.; Bogancs, J.; Nazarov, V.M.

    1979-12-01

    The surface boron concentration of Fe 40 Ni 40 P 14 B 6 , Fe 32 Ni 36 Cr 14 P 12 B 6 and Fe 40 Ni 40 B 20 metallic glasses was measured by neutron activation analysis on both sides of the ribbon samples. It was found that the boron concentration is always higher at the bright side of the ribbon than that at the dull side which is in contact with the cold surface of the wheel during the rapid quenching from the melt. A possible explanation is given in terms of the solid-liquid interface moving rapidly from the cooled surface to the free surface when preparing the samples. Range values of alpha-particles for some characteristic compositions of metallic glasses are tabulated. A mathematical technique for the deconvolution of experimental data is described and the listing of the Fortran program is enclosed. (author)

  7. 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)

  8. 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...

  9. Determination Of Natural Boron Concentration In Coffee Leaves, Using de Autobiography by Neutron Capture Technique

    International Nuclear Information System (INIS)

    Loria, L. G.; Jimenez, R.; Thellier, M.

    1999-01-01

    Determination of natural boron concentration in coffee leaves, using the autoradiography, by neutron capture technique. The boron absorption coefficient in young coffee leaves was measured using autoradiography by neutron capture. In two experiments carried out in April and November, 1996, it was found that the coefficient varies between 0.9 and 5.3 nmol/h. the concentration of natural boron in coffee leaves in regard to age, symptoms and treatment received was also studied, using the same technique. (Author) [es

  10. New Small LWR Core Designs using Particle Burnable Poisons for Low Boron Concentration

    International Nuclear Information System (INIS)

    Yoo, Ho Seong; Hwang, Dae Hee; Hong, Ser Gi

    2015-01-01

    The soluble boron has two major important roles in commercial PWR operations : 1) the control of the long-term reactivity to maintain criticality under normal operation, and 2) the shutdown of the reactor under accidents. However, the removal of the soluble boron gives several advantages in SMRs (Small Modular Reactor). These advantages resulted from the elimination of soluble boron include the significant simplification of nuclear power plant through the removal of pipes, pumps, and purification systems. Also, the use of soluble boron mitigates corrosion problems on the primary coolant loop. Furthermore, the soluble boron-free operation can remove an inadvertent boron dilution accident (BDA) which can lead to a significant insertion of positive reactivity. From the viewpoint of core physics, the removal of soluble boron or reduction of soluble boron concentration makes the moderator temperature coefficient (MTC) more negative. From the core design studies using new fuel assemblies, it is shown that the cores have very low critical soluble boron concentrations less than 500ppm, low peaking factors within the design targets, strong negative MTCs over cycles, and large enough shutdown margins both at BOC and EOC. However, the present cores have relatively low average discharge burnups of ∼ 30MWD/kg leading to low fuel economy because the cores use lots of non-fuel burnable poison rods to achieve very low critical boron concentrations. So, in the future, we will perform the trade-off study between the fuel discharge burnup and the boron concentrations by changing fuel assembly design and the core loading pattern

  11. New Small LWR Core Designs using Particle Burnable Poisons for Low Boron Concentration

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Ho Seong; Hwang, Dae Hee; Hong, Ser Gi [Kyung Hee University, Yongin (Korea, Republic of)

    2015-05-15

    The soluble boron has two major important roles in commercial PWR operations : 1) the control of the long-term reactivity to maintain criticality under normal operation, and 2) the shutdown of the reactor under accidents. However, the removal of the soluble boron gives several advantages in SMRs (Small Modular Reactor). These advantages resulted from the elimination of soluble boron include the significant simplification of nuclear power plant through the removal of pipes, pumps, and purification systems. Also, the use of soluble boron mitigates corrosion problems on the primary coolant loop. Furthermore, the soluble boron-free operation can remove an inadvertent boron dilution accident (BDA) which can lead to a significant insertion of positive reactivity. From the viewpoint of core physics, the removal of soluble boron or reduction of soluble boron concentration makes the moderator temperature coefficient (MTC) more negative. From the core design studies using new fuel assemblies, it is shown that the cores have very low critical soluble boron concentrations less than 500ppm, low peaking factors within the design targets, strong negative MTCs over cycles, and large enough shutdown margins both at BOC and EOC. However, the present cores have relatively low average discharge burnups of ∼ 30MWD/kg leading to low fuel economy because the cores use lots of non-fuel burnable poison rods to achieve very low critical boron concentrations. So, in the future, we will perform the trade-off study between the fuel discharge burnup and the boron concentrations by changing fuel assembly design and the core loading pattern.

  12. Development of cancer therapy facility of HANARO and medical research in BNCT; development of the technique for boron concentration analysis

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hee Dong; Byun, Soo Hyun; Sun, Gwang Min; Kim, Suk Kwon; Kim, In Jung; Park, Chang Su [Seoul National University, Seoul (Korea)

    2002-03-01

    Objective and Necessity of the Project- Development of a boron concentration analysis facility used for BNCT. - Development of the technique for boron concentration analysis. Contents and Scopes of the Project - Construction of the boron concentration analysis facility based on PGAA. Estimation of the neutron beam characteristics. -Establishment of the technique for the boron concentration analysis. - Estimation of the reliability for the boron analysis. Results of the Project -Installation of the boron concentration analysis facility at Hanaro. - Neutron beam characteristics are the sample position (neutron flux : 7.9 x 10{sup 7} n/cm{sup 2}s, Cd-ratio : 266) Technique for the boron concentration analysis. - Boron detection sensitivity and limit (detection sensitivity : 2, 131 cps/mg-B, detection limit : 67 ng for 10,000 sec). 63 refs., 37 figs., 13 tabs. (Author)

  13. Analysis of variation in few-group cross section behavior subjected to burnup and boron concentration

    International Nuclear Information System (INIS)

    Zhang Zongyao; Li Dongsheng.

    1986-01-01

    The paper analyzes the variations of few-group cross section behavior in neutron diffusion subjected to fuel burnup and critical boron concentration in a core. The influences of the behavior on the core excess reactivity, crirical boron concentration, power distribution and the yield of isotopes are also analyzed. A reactor core of samll-medium-sized nuclear power plant is analyzed as an example

  14. Behavior of Multiclass Pesticide Residue Concentrations during the Transformation from Rose Petals to Rose Absolute.

    Science.gov (United States)

    Tascone, Oriane; Fillâtre, Yoann; Roy, Céline; Meierhenrich, Uwe J

    2015-05-27

    This study investigates the concentrations of 54 multiclass pesticides during the transformation processes from rose petal to concrete and absolute using roses spiked with pesticides as a model. The concentrations of the pesticides were followed during the process of transforming the spiked rose flowers from an organic field into concrete and then into absolute. The rose flowers, the concrete, and the absolute, as well as their transformation intermediates, were analyzed for pesticide content using gas chromatography/tandem mass spectrometry. We observed that all the pesticides were extracted and concentrated in the absolute, with the exception of three molecules: fenthion, fenamiphos, and phorate. Typical pesticides were found to be concentrated by a factor of 100-300 from the rose flowers to the rose absolute. The observed effect of pesticide enrichment was also studied in roses and their extracts from four classically phytosanitary treated fields. Seventeen pesticides were detected in at least one of the extracts. Like the case for the spiked samples in our model, the pesticides present in the rose flowers from Turkey were concentrated in the absolute. Two pesticides, methidathion and chlorpyrifos, were quantified in the rose flowers at approximately 0.01 and 0.01-0.05 mg kg(-1), respectively, depending on the treated field. The concentrations determined for the corresponding rose absolutes were 4.7 mg kg(-1) for methidathion and 0.65-27.25 mg kg(-1) for chlorpyrifos.

  15. Development of automatic high-concentration boron measurement technique; Konodo hoso jido sokutei gijutsu no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Maeda, T.; Honda, S.; Ito, A. [Kyushu Electric Power Co. Inc., Fukuoka (Japan)

    1997-03-01

    The technology that can automatically measure the boron concentration in boric acid water was developed. A high-concentration boric acid solution must be held at a high temperature to prevent the deposition. Skill and precision ({plus_minus}0.2 to 0.3% for 10 to 2500 ppm as boron concentration, and {plus_minus}2 to 3% for 2500 to 25,000 ppm) are required to analyze the boric acid solution manually. In theory, the boron concentration in a wide range can be measured, and boron has a constant-temperature function. A density hydrometer method that facilitates the treatment and calibration in high precision and at low cost was chosen. The vibration period generated when vibration is given to the solution specimen put in a U-tube is higher as the density is lower. On the basis of this theory, the density of a specimen can be obtained according to the relation with the same data of the known-concentration boric acid water. The high-concentration boric acid water that cannot be measured by the existing boron densitometer can be measured directly. It can also be measured in a low-concentration area. The technique can be used in a laboratory as the simplified method that is replaced by the current manual analysis. The reduction effect of analytical chemical`s waste liquid can also be expected. In the electric power industry, automated equipment is required for high efficiency and labor saving. 13 figs., 3 tabs.

  16. Boron concentration measurements by alpha spectrometry and quantitative neutron autoradiography in cells and tissues treated with different boronated formulations and administration protocols

    International Nuclear Information System (INIS)

    Bortolussi, Silva; Ciani, Laura; Postuma, Ian; Protti, Nicoletta; Luca Reversi,; Bruschi, Piero; Ferrari, Cinzia; Cansolino, Laura; Panza, Luigi; Ristori, Sandra; Altieri, Saverio

    2014-01-01

    The possibility to measure boron concentration with high precision in tissues that will be irradiated represents a fundamental step for a safe and effective BNCT treatment. In Pavia, two techniques have been used for this purpose, a quantitative method based on charged particles spectrometry and a boron biodistribution imaging based on neutron autoradiography. A quantitative method to determine boron concentration by neutron autoradiography has been recently set-up and calibrated for the measurement of biological samples, both solid and liquid, in the frame of the feasibility study of BNCT. This technique was calibrated and the obtained results were cross checked with those of α spectrometry, in order to validate them. The comparisons were performed using tissues taken form animals treated with different boron administration protocols. Subsequently the quantitative neutron autoradiography was employed to measure osteosarcoma cell samples treated with BPA and with new boronated formulations. - Highlights: • A method for 10B measurements in samples based on neutron autoradiography was developed. • The results were compared with those of alpha spectrometry applied on tissue and cell samples. • Boronated liposomes were developed and administered to osteosarcoma cell cultures. • Neutron autoradiography was employed to measure boron concentration due to liposomes. • Liposomes were proved to be more effective in concentrating boron in cells than BPA

  17. Electrochemical characterization of doped diamond-coated carbon fibers at different boron concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, E.C. [INPE, CP 515, Sao Jose dos Campos, SP 12201-970 (Brazil)]. E-mail: erica@las.inpe.br; Diniz, A.V. [INPE, CP 515, Sao Jose dos Campos, SP 12201-970 (Brazil); Trava-Airoldi, V.J. [INPE, CP 515, Sao Jose dos Campos, SP 12201-970 (Brazil); Ferreira, N.G. [CTA-Divisao de Materiais, Sao Jose dos Campos, SP 12228-904 (Brazil)

    2005-08-01

    Doped diamond films have been deposited on carbon fibers (felt) obtained from polyacrylonitrile at different levels of boron doping. For a successful coating of the fibers, an ultrasonic pretreatment in a bath of diamond powder dissolved in hexane was required. Films were grown on both sample sides, simultaneously, by hot filament-assisted chemical vapour deposition technique at 750 deg. C from a 0.5% H{sub 2}/CH{sub 4} mixture at a total pressure of 6.5 x 10{sup 3} Pa. Boron was obtained from H{sub 2} forced to pass through a bubbler containing B{sub 2}O{sub 3} dissolved in methanol. The doping level studied corresponds to films with acceptor concentrations in the range of 6.5 x 10{sup 18} to 1.5 x 10{sup 21} cm{sup -} {sup 3}, obtained from Mott-Schottky plots. Scanning electron microscopy analyses evidenced fibers totally covered with high quality polycrystalline boron-doped diamond film, also confirmed by Raman spectroscopy spectra. Diamond electrodes grown on carbon fibers demonstrated similar electrochemical behavior obtained from films on Si substrate, for ferri/ferrocyanide redox couple as a function of boron content. The boron content influences electrochemical surface area. A lower boron concentration provides a higher growth rate that results in a higher surface area.

  18. The boron concentration measurement by the prompt gamma-ray analysis device at JRR-4

    International Nuclear Information System (INIS)

    Hori, N.; Torii, Y.; Yamamoto, K.; Kishi, T.; Takada, J.

    2000-01-01

    In determining the dose for BNCT, it is important to measure the boron concentration in blood as well as the thermal neutron fluence. To attain an accurate measurement of the boron concentration in the whole blood at about 30 ppm, the Prompt Gamma-ray Analysis (PGA) is adopted to enable the measurement with a high degree of accuracy in short time, since the chemical analysis technique has some difficulties on it. In order to install the PGA device in a swimming pool type research reactor JRR-4, the super-mirror for obtaining the necessary neutron flux in the space over the pool surface was perpendicularly placed, because the reactor had no horizontal experiment tube for this kind of use. As the accurate measurement of the boron concentration in whole blood using PGA is enabled herewith, the first medical irradiation for BNCT at JRR-4 was carried out on October 25, 1999. (author)

  19. Hydrogen-boron complexes in heavily boron-doped silicon treated with high concentration of hydrogen atoms

    International Nuclear Information System (INIS)

    Fukata, N.; Fukuda, S.; Sato, S.; Ishioka, K.; Kitajima, M.; Hishita, S.; Murakami, K.

    2006-01-01

    The formation of hydrogen (H)-related complexes was investigated in boron (B)-doped Si treated with high concentration of H. The isotope shifts of H-related Raman peaks by replacement of H to deuterium and 1 B to 11 B clearly showed the formation of the B-H complexes in which H directly bonds to B in Si. The results of the resistivity measurements suggested that the B acceptors are passivated via the formation of the B-H complexes, as well as the well-known passivation center in B-doped Si, namely, H-B passivation center

  20. Mapping absolute tissue endogenous fluorophore concentrations with chemometric wide-field fluorescence microscopy

    Science.gov (United States)

    Xu, Zhang; Reilley, Michael; Li, Run; Xu, Min

    2017-06-01

    We report chemometric wide-field fluorescence microscopy for imaging the spatial distribution and concentration of endogenous fluorophores in thin tissue sections. Nonnegative factorization aided by spatial diversity is used to learn both the spectral signature and the spatial distribution of endogenous fluorophores from microscopic fluorescence color images obtained under broadband excitation and detection. The absolute concentration map of individual fluorophores is derived by comparing the fluorescence from "pure" fluorophores under the identical imaging condition following the identification of the fluorescence species by its spectral signature. This method is then demonstrated by characterizing the concentration map of endogenous fluorophores (including tryptophan, elastin, nicotinamide adenine dinucleotide, and flavin adenine dinucleotide) for lung tissue specimens. The absolute concentrations of these fluorophores are all found to decrease significantly from normal, perilesional, to cancerous (squamous cell carcinoma) tissue. Discriminating tissue types using the absolute fluorophore concentration is found to be significantly more accurate than that achievable with the relative fluorescence strength. Quantification of fluorophores in terms of the absolute concentration map is also advantageous in eliminating the uncertainties due to system responses or measurement details, yielding more biologically relevant data, and simplifying the assessment of competing imaging approaches.

  1. Effects of iron concentration and redox states on failure of boron-free ...

    Indian Academy of Sciences (India)

    Effects of iron concentration and redox states on failure of boron-free E-glass fibres under applied stress in different conditions ... Materials, Donghua University, Shanghai 201620, China; Material Research Center, Missouri University of Science and Technology, Rolla 65409, USA; Fiber Glass Science and Technology, ...

  2. Noncrucial role of the defects in the splitting for hydrogen implanted silicon with high boron concentration

    International Nuclear Information System (INIS)

    Popov, V.P.; Stas, V.F.; Antonova, I.V.

    1999-01-01

    The present work deals with the investigation of the electrical and structural properties of heavily boron-doped silicon irradiated by hydrogen. Blistering and splitting processes are enhanced with an increase in boron concentration in the crystal. The measured values of perpendicular strain are over 0.7% which corresponds to a gas overpressure of 0.5 GPa. Processes which lead to blistering and splitting is better described in the frame of a gas pressure model than a model of local stress caused by the defects

  3. ACRE: Absolute concentration robustness exploration in module-based combinatorial networks

    KAUST Repository

    Kuwahara, Hiroyuki; Umarov, Ramzan; Almasri, Islam; Gao, Xin

    2017-01-01

    To engineer cells for industrial-scale application, a deep understanding of how to design molecular control mechanisms to tightly maintain functional stability under various fluctuations is crucial. Absolute concentration robustness (ACR) is a category of robustness in reaction network models in which the steady-state concentration of a molecular species is guaranteed to be invariant even with perturbations in the other molecular species in the network. Here, we introduce a software tool, absolute concentration robustness explorer (ACRE), which efficiently explores combinatorial biochemical networks for the ACR property. ACRE has a user-friendly interface, and it can facilitate efficient analysis of key structural features that guarantee the presence and the absence of the ACR property from combinatorial networks. Such analysis is expected to be useful in synthetic biology as it can increase our understanding of how to design molecular mechanisms to tightly control the concentration of molecular species. ACRE is freely available at https://github.com/ramzan1990/ACRE.

  4. ACRE: Absolute concentration robustness exploration in module-based combinatorial networks

    KAUST Repository

    Kuwahara, Hiroyuki

    2017-03-01

    To engineer cells for industrial-scale application, a deep understanding of how to design molecular control mechanisms to tightly maintain functional stability under various fluctuations is crucial. Absolute concentration robustness (ACR) is a category of robustness in reaction network models in which the steady-state concentration of a molecular species is guaranteed to be invariant even with perturbations in the other molecular species in the network. Here, we introduce a software tool, absolute concentration robustness explorer (ACRE), which efficiently explores combinatorial biochemical networks for the ACR property. ACRE has a user-friendly interface, and it can facilitate efficient analysis of key structural features that guarantee the presence and the absence of the ACR property from combinatorial networks. Such analysis is expected to be useful in synthetic biology as it can increase our understanding of how to design molecular mechanisms to tightly control the concentration of molecular species. ACRE is freely available at https://github.com/ramzan1990/ACRE.

  5. Absolute choline concentration measured by quantitative proton MR spectroscopy correlates with cell density in meningioma

    Energy Technology Data Exchange (ETDEWEB)

    Yue, Qiang [University of Tsukuba, Department of Neurosurgery, Institute of Clinical Medicine, Tsukuba Science City, Ibaraki (Japan)]|[West China Hospital of Sichuan University, Huaxi MR Research Center, Department of Radiology, Chengdu (China); Shibata, Yasushi; Kawamura, Hiraku; Matsumura, Akira [University of Tsukuba, Department of Neurosurgery, Institute of Clinical Medicine, Tsukuba Science City, Ibaraki (Japan); Isobe, Tomonori [Kitasato University, Department of Medical Technology, School of Allied Health Sciences, Minato, Tokyo (Japan); Anno, Izumi [University of Tsukuba, Department of Radiology, Institute of Clinical Medicine, Tsukuba, Ibaraki (Japan); Gong, Qi-Yong [West China Hospital of Sichuan University, Huaxi MR Research Center, Department of Radiology, Chengdu (China)]|[University of Liverpool, Division of Medical Imaging, Faculty of Medicine, Liverpool (United Kingdom)

    2009-01-15

    This study was aimed to investigate the relationship between quantitative proton magnetic resonance spectroscopy (1H-MRS) and pathological changes in meningioma. Twenty-two meningioma cases underwent single voxel 1H-MRS (point-resolved spectroscopy sequence, repetition time/echo time = 2,000 ms/68, 136, 272 ms). Absolute choline (Cho) concentration was calculated using tissue water as the internal reference and corrected according to intra-voxel cystic/necrotic parts. Pathological specimens were stained with MIB-1 antibody to measure cell density and proliferation index. Correlation analysis was performed between absolute Cho concentration and cell density and MIB-1 labeled proliferation index. Average Cho concentration of all meningiomas before correction was 2.95 {+-} 0.86 mmol/kg wet weight. It was increased to 3.23 {+-} 1.15 mmol/kg wet weight after correction. Average cell density of all meningiomas was 333 {+-} 119 cells/HPF, and average proliferation index was 2.93 {+-} 5.72%. A linear, positive correlation between cell density and Cho concentration was observed (r = 0.650, P = 0.001). After correction of Cho concentration, the correlation became more significant (r = 0.737, P < 0.001). However, no significant correlation between Cho concentration and proliferation index was found. There seemed to be a positive correlation trend after correction of Cho concentration but did not reach significant level. Absolute Cho concentration, especially Cho concentration corrected according to intra-voxel cystic/necrotic parts, reflects cell density of meningioma. (orig.)

  6. The role of silicon interstitials in the deactivation and reactivation of high concentration boron profiles

    Energy Technology Data Exchange (ETDEWEB)

    Aboy, Maria [Campus Miguel Delibes, University of Valladolid, 47011 Valladolid (Spain)]. E-mail: marabo@tel.uva.es; Pelaz, Lourdes [Campus Miguel Delibes, University of Valladolid, 47011 Valladolid (Spain); Marques, Luis A. [Campus Miguel Delibes, University of Valladolid, 47011 Valladolid (Spain); Lopez, Pedro [Campus Miguel Delibes, University of Valladolid, 47011 Valladolid (Spain); Barbolla, Juan [Campus Miguel Delibes, University of Valladolid, 47011 Valladolid (Spain); Venezia, V.C. [Philips Research Leuven, Leuven (Belgium); Duffy, R. [Philips Research Leuven, Leuven (Belgium); Griffin, Peter B. [Stanford University, Stanford, CA (United States)

    2004-12-15

    Boron cluster formation and dissolution in high concentration B profiles and the role of Si interstitials in these processes are analyzed by kinetic non-lattice Monte Carlo atomistic simulations. For this purpose, we use theoretical structures as simplifications of boron implants into preamorphized Si, followed by low-temperature solid phase epitaxial (SPE) regrowth or laser thermal annealing process. We observe that in the presence of high B concentrations (above 10{sup 20} cm{sup -3}), significant deactivation occurs during high temperature anneal, even in the presence of only equilibrium Si interstitials. The presence of additional Si interstitials from an end of range (EOR) damage region accelerates the deactivation process and makes B deactivation slightly higher. We show that B deactivation and reactivation processes can be clearly correlated to the evolution of Si interstitial defects at the EOR. The minimum level of activation occurs when the Si interstitial defects at EOR dissolve or form very stable defects.

  7. Polymeric Luminescent Compositions Doped with Beta-Diketonates Boron Difluoride as Material for Luminescent Solar Concentrator

    Science.gov (United States)

    Khrebtov, A. A.; Fedorenko, E. V.; Reutov, V. A.

    2017-11-01

    In this paper we investigated polymeric luminescent compositions based on polystyrene doped with beta diketonates boron difluoride. Transparent films with effective absorption in the ultraviolet and blue regions of the spectrum were obtained. Polymeric luminescent compositions based on the mixture of dyes allow expanding the absorption region and increase the radiation shift. A luminescent solar concentrator consisting of a glass plate coated with such film can be used for photovoltaic window application.

  8. Microfabricated Collector-Generator Electrode Sensor for Measuring Absolute pH and Oxygen Concentrations.

    Science.gov (United States)

    Dengler, Adam K; Wightman, R Mark; McCarty, Gregory S

    2015-10-20

    Fast-scan cyclic voltammetry (FSCV) has attracted attention for studying in vivo neurotransmission due to its subsecond temporal resolution, selectivity, and sensitivity. Traditional FSCV measurements use background subtraction to isolate changes in the local electrochemical environment, providing detailed information on fluctuations in the concentration of electroactive species. This background subtraction removes information about constant or slowly changing concentrations. However, determination of background concentrations is still important for understanding functioning brain tissue. For example, neural activity is known to consume oxygen and produce carbon dioxide which affects local levels of oxygen and pH. Here, we present a microfabricated microelectrode array which uses FSCV to detect the absolute levels of oxygen and pH in vitro. The sensor is a collector-generator electrode array with carbon microelectrodes spaced 5 μm apart. In this work, a periodic potential step is applied at the generator producing transient local changes in the electrochemical environment. The collector electrode continuously performs FSCV enabling these induced changes in concentration to be recorded with the sensitivity and selectivity of FSCV. A negative potential step applied at the generator produces a transient local pH shift at the collector. The generator-induced pH signal is detected using FSCV at the collector and correlated to absolute solution pH by postcalibration of the anodic peak position. In addition, in oxygenated solutions a negative potential step at the generator produces hydrogen peroxide by reducing oxygen. Hydrogen peroxide is detected with FSCV at the collector electrode, and the magnitude of the oxidative peak is proportional to absolute oxygen concentrations. Oxygen interference on the pH signal is minimal and can be accounted for with a postcalibration.

  9. Study on concentrating treatment test of simulated radioactive wastewater containing boron by reverse osmosis membrane in PWR NPP

    International Nuclear Information System (INIS)

    Ye Xinnan; Jiang Baihua; Fan Wenwen; Zhang Zhiyin; Yang Cangsheng

    2015-01-01

    The reverse osmosis membrane equipment in PWR NPP was employed to investigate the application of pilot scale system in the radioactive wastewater treatment at the full recirculation operation. The removal performance of the equipment for the boron and the radioactivity nuclide were studied, respectively. The experimental results show that the removal efficiency of the aromatic polyamide composite reverse osmosis membrane for boron is over 83.3% and the concentration of boron in concentrate is over 10000 mg/L. The experimental results also show that the removal efficiency of two nuclides including cobalt and cesium is over 97.9%. (authors)

  10. Effect of aluminium concentration and boron dopant on environmental embrittlement in FeAl aluminides

    International Nuclear Information System (INIS)

    Liu, C.T.; George, E.P.

    1991-01-01

    This paper reports on the room-temperature tensile properties of FeAl aluminides determined as functions of aluminum concentration (35 to 43 at. % Al), test environment, and surface (oil) coating. The two lower aluminum alloys containing 35 and 36.5% Al are prone to severe environmental embrittlement, while the two higher aluminum alloys with 40 and 43% Al are much less sensitive to change in test environment and surface coating. The reason for the different behavior is that the grain boundaries are intrinsically weak in the higher aluminum alloys, and these weak boundaries dominate the low ductility and brittle fracture behavior of the 40 and 43% Al alloys. When boron is added to the 40% Al alloy as a grain-boundary strengthener, the environmental effect becomes prominent. In this case, the tensile ductility of the boron-doped alloy, just like that of the lower aluminum alloys, can be dramatically improved by control of test environment (e.g. dry oxygen vs air). Strong segregation of boron to the grain boundaries, with a segregation factor of 43, was revealed by Auger analyses

  11. High-concentration boron doping of graphene nanoplatelets by simple thermal annealing and their supercapacitive properties

    Science.gov (United States)

    Yeom, Da-Young; Jeon, Woojin; Tu, Nguyen Dien Kha; Yeo, So Young; Lee, Sang-Soo; Sung, Bong June; Chang, Hyejung; Lim, Jung Ah; Kim, Heesuk

    2015-05-01

    For the utilization of graphene in various energy storage and conversion applications, it must be synthesized in bulk with reliable and controllable electrical properties. Although nitrogen-doped graphene shows a high doping efficiency, its electrical properties can be easily affected by oxygen and water impurities from the environment. We here report that boron-doped graphene nanoplatelets with desirable electrical properties can be prepared by the simultaneous reduction and boron-doping of graphene oxide (GO) at a high annealing temperature. B-doped graphene nanoplatelets prepared at 1000 °C show a maximum boron concentration of 6.04 ± 1.44 at %, which is the highest value among B-doped graphenes prepared using various methods. With well-mixed GO and g-B2O3 as the dopant, highly uniform doping is achieved for potentially gram-scale production. In addition, as a proof-of-concept, highly B-doped graphene nanoplatelets were used as an electrode of an electrochemical double-layer capacitor (EDLC) and showed an excellent specific capacitance value of 448 F/g in an aqueous electrolyte without additional conductive additives. We believe that B-doped graphene nanoplatelets can also be used in other applications such as electrocatalyst and nano-electronics because of their reliable and controllable electrical properties regardless of the outer environment.

  12. High-concentration boron doping of graphene nanoplatelets by simple thermal annealing and their supercapacitive properties.

    Science.gov (United States)

    Yeom, Da-Young; Jeon, Woojin; Tu, Nguyen Dien Kha; Yeo, So Young; Lee, Sang-Soo; Sung, Bong June; Chang, Hyejung; Lim, Jung Ah; Kim, Heesuk

    2015-05-05

    For the utilization of graphene in various energy storage and conversion applications, it must be synthesized in bulk with reliable and controllable electrical properties. Although nitrogen-doped graphene shows a high doping efficiency, its electrical properties can be easily affected by oxygen and water impurities from the environment. We here report that boron-doped graphene nanoplatelets with desirable electrical properties can be prepared by the simultaneous reduction and boron-doping of graphene oxide (GO) at a high annealing temperature. B-doped graphene nanoplatelets prepared at 1000 °C show a maximum boron concentration of 6.04 ± 1.44 at %, which is the highest value among B-doped graphenes prepared using various methods. With well-mixed GO and g-B2O3 as the dopant, highly uniform doping is achieved for potentially gram-scale production. In addition, as a proof-of-concept, highly B-doped graphene nanoplatelets were used as an electrode of an electrochemical double-layer capacitor (EDLC) and showed an excellent specific capacitance value of 448 F/g in an aqueous electrolyte without additional conductive additives. We believe that B-doped graphene nanoplatelets can also be used in other applications such as electrocatalyst and nano-electronics because of their reliable and controllable electrical properties regardless of the outer environment.

  13. Electrochemical oxidation of biological pretreated and membrane separated landfill leachate concentrates on boron doped diamond anode

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Bo, E-mail: 357436235@qq.com [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Yu, Zhiming, E-mail: zhiming@csu.edu.cn [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); Wei, Qiuping, E-mail: qiupwei@csu.edu.cn [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); Long, HangYu, E-mail: 55686385@qq.com [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Xie, Youneng, E-mail: 1187272844@qq.com [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Wang, Yijia, E-mail: 503630433@qq.com [School of Materials Science and Engineering, Central South University, Changsha 410083 (China)

    2016-07-30

    Highlights: • High quality boron-doped diamond film electrodes were synthesized on Nb substrates. • Electrochemical oxidation on boron-doped diamond anode is an effective method for treating landfill leachate concentrates. • Optimal operating conditions for electrochemical oxidation of landfill leachate concentrates is determined. • 87.5% COD removal and 74.06% NH{sub 3}−N removal were achieved after 6 h treatment. - Abstract: In the present study, the high quality boron-doped diamond (BDD) electrodes with excellent electrochemical properties were deposited on niobium (Nb) substrates by hot filament chemical vapor deposition (HFCVD) method. The electrochemical oxidation of landfill leachate concentrates from disc tube reverse osmosis (DTRO) process over a BDD anode was investigated. The effects of varying operating parameters, such as current density, initial pH, flow velocity and cathode material on degradation efficiency were also evaluated following changes in chemical oxygen demand (COD) and ammonium nitrogen (NH{sub 3}−N). The instantaneous current efficiency (ICE) was used to appraise different operating conditions. As a result, the best conditions obtained were as follows, current density 50 mA cm{sup −2}, pH 5.16, flow velocity 6 L h{sup −1}. Under these conditions, 87.5% COD and 74.06% NH{sub 3}−N removal were achieved after 6 h treatment, with specific energy consumption of 223.2 kWh m{sup −3}. In short, these results indicated that the electrochemical oxidation with BDD/Nb anode is an effective method for the treatment of landfill leachate concentrates.

  14. 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.

  15. Absolute quantitative autoradiography of low concentrations of [125I]-labeled proteins in arterial tissue

    International Nuclear Information System (INIS)

    Schnitzer, J.J.; Morrel, E.M.; Colton, C.K.; Smith, K.A.; Stemerman, M.B.

    1987-01-01

    We developed a method for absolute quantitative autoradiographic measurement of very low concentrations of [ 125 I]-labeled proteins in arterial tissue using Kodak NTB-2 nuclear emulsion. A precise linear relationship between measured silver grain density and isotope concentration was obtained with uniformly labeled standard sources composed of epoxy-embedded gelatin containing glutaraldehyde-fixed [ 125 I]-albumin. For up to 308-day exposures of 1 micron-thick tissue sections, background grain densities ranged from about two to eight grains/1000 micron 2, and the technique was sensitive to as little as about one grain/1000 micron 2 above background, which correspond to a radioactivity concentration of about 2 x 10(4) cpm/ml. A detailed statistical analysis of variability was performed and the sum of all sources of variation quantified. The half distance for spatial resolution was 1.7 micron. Both visual and automated techniques were employed for quantitative grain density analysis. The method was illustrated by measurement of in vivo transmural [ 125 I]-low-density lipoprotein [( 125 I]-LDL) concentration profiles in de-endothelialized rabbit thoracic aortic wall

  16. 2.4. The kinetics of hydrochloric-acid decomposition of calcined concentrate of boron raw material of Ak-Arkhar Deposit

    International Nuclear Information System (INIS)

    Mirsaidov, U.M.; Kurbonov, A.S.; Mamatov, E.D.

    2015-01-01

    Present article is devoted to kinetics of hydrochloric-acid decomposition of calcined concentrate of boron raw material of Ak-Arkhar Deposit. The experimental data of dependence of hydrochloric-acid decomposition of calcined boron raw material for boron oxide extraction on temperature (20-80 deg C) and process duration (15-60 min) were considered. It was defined that at temperature increasing the boron oxide extraction from borosilicate raw material increases from 24.1 till 86.8%. The constants of decomposition rate of boron raw material were calculated.

  17. Absolute estimation of initial concentrations of amplicon in a real-time RT-PCR process

    Directory of Open Access Journals (Sweden)

    Kohn Michael

    2007-10-01

    Full Text Available Abstract Background Since real time PCR was first developed, several approaches to estimating the initial quantity of template in an RT-PCR reaction have been tried. While initially only the early thermal cycles corresponding to exponential duplication were used, lately there has been an effort to use all of the cycles in a PCR. The efforts have included both fitting empirical sigmoid curves and more elaborate mechanistic models that explore the chemical reactions taking place during each cycle. The more elaborate mechanistic models require many more parameters than can be fit from a single amplification, while the empirical models provide little insight and are difficult to tailor to specific reactants. Results We directly estimate the initial amount of amplicon using a simplified mechanistic model based on chemical reactions in the annealing step of the PCR. The basic model includes the duplication of DNA with the digestion of Taqman probe and the re-annealing between previously synthesized DNA strands of opposite orientation. By modelling the amount of Taqman probe digested and matching that with the observed fluorescence, the conversion factor between the number of fluorescing dye molecules and observed fluorescent emission can be estimated, along with the absolute initial amount of amplicon and the rate parameter for re-annealing. The model is applied to several PCR reactions with known amounts of amplicon and is shown to work reasonably well. An expanded version of the model allows duplication of amplicon without release of fluorescent dye, by adding 1 more parameter to the model. The additional process is helpful in most cases where the initial primer concentration exceeds the initial probe concentration. Software for applying the algorithm to data may be downloaded at http://www.niehs.nih.gov/research/resources/software/pcranalyzer/ Conclusion We present proof of the principle that a mechanistically based model can be fit to observations

  18. Early diagnosis of myocardial infarction using absolute and relative changes in cardiac troponin concentrations

    OpenAIRE

    Irfan Affan Bin; Reichlin Tobias R.; Twerenbold Raphael; Meister Marc; Moehring Berit; Wildi Karin; Bassetti Stefano; Zellweger Christa; Gimenez Maria Rubini; Hoeller Rebeca; Murray Karsten; Sou SeoungMann; Mueller Mira; Mosimann Tamina; Reiter Miriam

    2013-01-01

    Background: Absolute changes in high sensitivity cardiac troponin T (hs cTnT) seem to have higher diagnostic accuracy in the early diagnosis of acute myocardial infarction compared with relative changes. It is unknown whether the same applies to high sensitivity cardiac troponin I (hs cTnI) assays and whether the combination of absolute and relative change might further increase accuracy. Methods: In a prospective international multicenter study high sensitivity cardiac troponin (hs cTn) was ...

  19. Early diagnosis of myocardial infarction using absolute and relative changes in cardiac troponin concentrations.

    Science.gov (United States)

    Irfan, Affan; Reichlin, Tobias; Twerenbold, Raphael; Meister, Marc; Moehring, Berit; Wildi, Karin; Bassetti, Stefano; Zellweger, Christa; Gimenez, Maria Rubini; Hoeller, Rebeca; Murray, Karsten; Sou, Seoung Mann; Mueller, Mira; Mosimann, Tamina; Reiter, Miriam; Haaf, Philip; Ziller, Ronny; Freidank, Heike; Osswald, Stefan; Mueller, Christian

    2013-09-01

    Absolute changes in high-sensitivity cardiac troponin T (hs-cTnT) seem to have higher diagnostic accuracy in the early diagnosis of acute myocardial infarction compared with relative changes. It is unknown whether the same applies to high-sensitivity cardiac troponin I (hs-cTnI) assays and whether the combination of absolute and relative change might further increase accuracy. In a prospective, international multicenter study, high-sensitivity cardiac troponin (hs-cTn) was measured with 3 novel assays (hs-cTnT, Roche Diagnostics Corp, Indianapolis, Ind; hs-cTnI, Beckman Coulter Inc, Brea, Calif; hs-cTnI, Siemens, Munich, Germany) in a blinded fashion at presentation and after 1 and 2 hours in a blinded fashion in 830 unselected patients with suspected acute myocardial infarction. The final diagnosis was adjudicated by 2 independent cardiologists. The area under the receiver operating characteristic curve for diagnosing acute myocardial infarction was significantly higher for 1- and 2-hour absolute versus relative hs-cTn changes for all 3 assays (P Siemens, 0.96 [95% CI, 0.93-0.99]) were high and provided some benefit compared with the use of absolute change alone for hs-cTnT, but not for the hs-cTnI assays. Reclassification analysis confirmed the superiority of absolute changes versus relative changes. Absolute changes seem to be the preferred metrics for both hs-cTnT and hs-cTnI in the early diagnosis of acute myocardial infarction. The combination of absolute and relative changes provides a small added value for hs-cTnT, but not for hs-cTnI. Copyright © 2013 Elsevier Inc. All rights reserved.

  20. Investigate the capability of INAA absolute method to determine the concentrations of 238U and 232Th in rock samples

    International Nuclear Information System (INIS)

    Alnour, I.A.

    2014-01-01

    This work aimed to study the capability of INAA absolute method in determining the elemental concentration of 238 U and 232 Th in the rock samples. The INAA absolute method was implemented in PUSPATI TRIGA Mark II research reactor, Malaysian Nuclear Agency (NM). The accuracy of INAA absolute method was performed by analyzing the IAEA certified reference material (CRM) Soil-7. The analytical results showed the deviations between experimental and certified values were mostly less than 10 % with Z-score in most cases less than 1. In general, the results of analysed CRM Soil-7 show a good agreement between certified and experimental results which mean that the INAA absolute method can be used accurately for elemental analysis of uranium and thorium in various types of samples. The concentration of 238 U and 232 Th ranged from 1.77 to 24.25 and 0.88 to 95.50 ppm respectively. The highest value of 238 U and 232 Th was recorded for granite rock sample G17 of 238 U and sample G9 of 232 Th, whereas the lower value was 1.77 ppm of 238 U recorded in sandstone rock and 0.88 ppm of 232 Th for gabbro. Moreover, a comparison of the 238 U and 232 Th results obtained by the INAA absolute method shows an acceptable level of consistency with those obtained by the INAA relative method. (author)

  1. Influence of boron concentration on growth characteristic and electro-catalytic performance of boron-doped diamond electrodes prepared by direct current plasma chemical vapor deposition

    International Nuclear Information System (INIS)

    Feng Yujie; Lv Jiangwei; Liu Junfeng; Gao Na; Peng Hongyan; Chen Yuqiang

    2011-01-01

    A series of boron-doped diamond (BDD) electrodes were prepared by direct current plasma chemical vapor deposition (DC-PCVD) with different compositions of CH 4 /H 2 /B(OCH 3 ) 3 gas mixture. A maximum growth rate of 0.65 mg cm -2 h -1 was obtained with CH 4 /H 2 /B(OCH 3 ) 3 radio of 4/190/10 and this growth condition was also a turning point for discharge plasma stability which arose from the addition of B(OCH 3 ) 3 that changed electron energy distribution and influenced the plasma reaction. The surface coating structure and electro-catalytic performance of the BDD electrodes were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, Hall test, and electrochemical measurement and electro-catalytic oxidation in phenol solution. It is suggested that the boron doping level and the thermal stress in the films are the main factors affecting the electro-catalytic characteristics of the electrodes. Low boron doping level with CH 4 /H 2 /B(OCH 3 ) 3 ratio of 4/199/1 decreased the films electrical conductivity and its electro-catalytic activity. When the carrier concentration in the films reached around 10 20 cm -3 with CH 4 /H 2 /B(OCH 3 ) 3 ratio over a range of 4/195/5-4/185/15, the thermal stress in the films was the key reason that influenced the electro-catalytic activity of the electrodes for its effect on diamond lattice expansion. Therefore, the BDD electrode with modest CH 4 /H 2 /B(OCH 3 ) 3 ratio of 4/190/10 possessed the best phenol removal efficiency.

  2. Origin of high ammonium, arsenic and boron concentrations in the proximity of a mine: Natural vs. anthropogenic processes

    Energy Technology Data Exchange (ETDEWEB)

    Scheiber, Laura, E-mail: scheiber.ls@gmail.com [Institute of Environmental Assessment and Water Research, CSIC, Jordi Girona 18. E-08034 Barcelona (Spain); Ayora, Carlos; Vázquez-Suñé, Enric [Institute of Environmental Assessment and Water Research, CSIC, Jordi Girona 18. E-08034 Barcelona (Spain); Cendón, Dioni I. [Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia); School of Biological, Earth and Environmental Sciences (BEES), University of New South Wales (UNSW), NSW 2052 (Australia); Soler, Albert [Departament de Cristallografia, Mineralogia i Dipòsits Minerals, Facultat de Geologia, Universitat de Barcelona, C/Martí Franquès, sn., Barcelona (Spain); Baquero, Juan Carlos [Cobre Las Cruces S.A., Carretera SE-3410 km 4, 41860 Gerena, Sevilla (Spain)

    2016-01-15

    High ammonium (NH{sub 4}), arsenic (As) and boron (B) concentrations are found in aquifers worldwide and are often related to human activities. However, natural processes can also lead to groundwater quality problems. High NH{sub 4}, As and B concentrations have been identified in the confined, deep portion of the Niebla-Posadas aquifer, which is near the Cobre Las Cruces (CLC) mining complex. The mine has implemented a Drainage and Reinjection System comprising two rings of wells around the open pit mine, were the internal ring drains and the external ring is used for water reinjection into the aquifer. Differentiating geogenic and anthropogenic sources and processes is therefore crucial to ensuring good management of groundwater in this sensitive area where groundwater is extensively used for agriculture, industry, mining and human supply. No NH{sub 4}, As and B are found in the recharge area, but their concentrations increase with depth, salinity and residence time of water in the aquifer. The increased salinity down-flow is interpreted as the result of natural mixing between infiltrated meteoric water and the remains of connate waters (up to 8%) trapped within the pores. Ammonium and boron are interpreted as the result of marine solid organic matter degradation by the sulfate dissolved in the recharge water. The light δ{sup 15}N{sub NH4} values confirm that its origin is linked to marine organic matter. High arsenic concentrations in groundwater are interpreted as being derived from reductive dissolution of As-bearing goethite by dissolved organic matter. The lack of correlation between dissolved Fe and As is explained by the massive precipitation of siderite, which is abundantly found in the mineralization. Therefore, the presence of high arsenic, ammonium and boron concentrations is attributed to natural processes. Ammonium, arsenic, boron and salinity define three zones of groundwater quality: the first zone is close to the recharge area and contains water

  3. Origin of high ammonium, arsenic and boron concentrations in the proximity of a mine: Natural vs. anthropogenic processes

    International Nuclear Information System (INIS)

    Scheiber, Laura; Ayora, Carlos; Vázquez-Suñé, Enric; Cendón, Dioni I.; Soler, Albert; Baquero, Juan Carlos

    2016-01-01

    High ammonium (NH_4), arsenic (As) and boron (B) concentrations are found in aquifers worldwide and are often related to human activities. However, natural processes can also lead to groundwater quality problems. High NH_4, As and B concentrations have been identified in the confined, deep portion of the Niebla-Posadas aquifer, which is near the Cobre Las Cruces (CLC) mining complex. The mine has implemented a Drainage and Reinjection System comprising two rings of wells around the open pit mine, were the internal ring drains and the external ring is used for water reinjection into the aquifer. Differentiating geogenic and anthropogenic sources and processes is therefore crucial to ensuring good management of groundwater in this sensitive area where groundwater is extensively used for agriculture, industry, mining and human supply. No NH_4, As and B are found in the recharge area, but their concentrations increase with depth, salinity and residence time of water in the aquifer. The increased salinity down-flow is interpreted as the result of natural mixing between infiltrated meteoric water and the remains of connate waters (up to 8%) trapped within the pores. Ammonium and boron are interpreted as the result of marine solid organic matter degradation by the sulfate dissolved in the recharge water. The light δ"1"5N_N_H_4 values confirm that its origin is linked to marine organic matter. High arsenic concentrations in groundwater are interpreted as being derived from reductive dissolution of As-bearing goethite by dissolved organic matter. The lack of correlation between dissolved Fe and As is explained by the massive precipitation of siderite, which is abundantly found in the mineralization. Therefore, the presence of high arsenic, ammonium and boron concentrations is attributed to natural processes. Ammonium, arsenic, boron and salinity define three zones of groundwater quality: the first zone is close to the recharge area and contains water of sufficient quality

  4. Origin of high ammonium, arsenic and boron concentrations in the proximity of a mine: Natural vs. anthropogenic processes.

    Science.gov (United States)

    Scheiber, Laura; Ayora, Carlos; Vázquez-Suñé, Enric; Cendón, Dioni I; Soler, Albert; Baquero, Juan Carlos

    2016-01-15

    High ammonium (NH4), arsenic (As) and boron (B) concentrations are found in aquifers worldwide and are often related to human activities. However, natural processes can also lead to groundwater quality problems. High NH4, As and B concentrations have been identified in the confined, deep portion of the Niebla-Posadas aquifer, which is near the Cobre Las Cruces (CLC) mining complex. The mine has implemented a Drainage and Reinjection System comprising two rings of wells around the open pit mine, were the internal ring drains and the external ring is used for water reinjection into the aquifer. Differentiating geogenic and anthropogenic sources and processes is therefore crucial to ensuring good management of groundwater in this sensitive area where groundwater is extensively used for agriculture, industry, mining and human supply. No NH4, As and B are found in the recharge area, but their concentrations increase with depth, salinity and residence time of water in the aquifer. The increased salinity down-flow is interpreted as the result of natural mixing between infiltrated meteoric water and the remains of connate waters (up to 8%) trapped within the pores. Ammonium and boron are interpreted as the result of marine solid organic matter degradation by the sulfate dissolved in the recharge water. The light δ(15)NNH4 values confirm that its origin is linked to marine organic matter. High arsenic concentrations in groundwater are interpreted as being derived from reductive dissolution of As-bearing goethite by dissolved organic matter. The lack of correlation between dissolved Fe and As is explained by the massive precipitation of siderite, which is abundantly found in the mineralization. Therefore, the presence of high arsenic, ammonium and boron concentrations is attributed to natural processes. Ammonium, arsenic, boron and salinity define three zones of groundwater quality: the first zone is close to the recharge area and contains water of sufficient quality for

  5. Effect of concentrated light on morphology and vibrational properties of boron and tantalum mixtures

    Directory of Open Access Journals (Sweden)

    Lina Sartinska

    2018-03-01

    Full Text Available Heating a mixture of boron (impurities: carbon ∼ B50C2, boric acid – H3BO3 and tantalum (Ta powders in nitrogen flow in a xenon high-flux optical furnace was performed. As-received powder composed of h-BN, H3BO3, TaB2, B9H11 and a number of other phases including β-rhombohedral boron, apparently, heavily doped with Ta. FT–IR examination of any sample of the material reveals the complicated vibration spectrum containing, in particular, an absorption band near 2260 cm−1. The shapes of these bands are different for samples because powders were synthesized at different temperatures. Known, that in β-rhombohedral boron lattice, there are nano-sized voids of different types, which allow an accommodation of single atoms or small groups of atoms. Theoretical calculations performed by the method of quasi-classical type yields the same value, 2260 cm−1, for the vibrations frequency of Ta atoms in D-type crystallographic voids in β-rhombohedral boron lattice. Since, Ta atoms are known to prefer accommodation just in D-voids the experimentally detected bands can be identified with localized vibrations of Ta atoms. Keywords: Condensed matter physics, Materials science, Nanotechnology

  6. Quantitative SIMS measurement of high concentration of boron in silicon (up to 20 at.%) using an isotopic comparative method

    International Nuclear Information System (INIS)

    Dubois, Christiane; Prudon, Gilles; Gautier, Brice; Dupuy, Jean-Claude

    2008-01-01

    Highly boron doped (up to 20 at.%) silicon samples have been analysed by SIMS with the aim of quantifying the boron concentration in a range where the dilute regime may not be valid any more. An original method is used based on the simultaneous analysis of two different isotopes, namely 10 B and 11 B, in order that the known concentration of the first isotope (initially present with a far lower, constant concentration) is the basis of the quantification of the concentration of the second, present with a very high dose. Argon and oxygen beams have been used and conclusions are drawn about the presence of matrix effects in the case of the analysis of highly doped samples. It appears that only the use of a 8 keV O 2 + beam leads to a significant matrix effect, whereas it is nearly absent in the case of an analysis under 8 keV Ar + beam. The proposed method may be applied to any element showing at least two isotopes in any binary alloys under any primary beam

  7. Neutronic-thermohydraulic oscillatory instability in modern PWRs due to high concentrations of boron in the water

    International Nuclear Information System (INIS)

    Novelli, A.

    1985-01-01

    Conspicuous amounts of boric acid are normally dissolved into the moderator of a modern PWR, especially in BOL operative conditions. If the concentration of such a neutronic poison attains certain limits, the nuclear temperature coefficient of the moderator, which is highly negative in the absence of boron, may turn about and reach positive values, due to the strong thermal expansion of the water. A dynamical model of a PWR system is presented, facilitating a quick stability analysis related to the co-ordination of boric acid solution in the water and control-rod insertion in the core. (author)

  8. Arsenic, Boron, and Fluoride Concentrations in Ground Water in and Near Diabase Intrusions, Newark Basin, Southeastern Pennsylvania

    Science.gov (United States)

    Senior, Lisa A.; Sloto, Ronald A.

    2006-01-01

    During an investigation in 2000 by the U.S. Environmental Protection Agency (USEPA) of possible contaminant releases from an industrial facility on Congo Road near Gilbertsville in Berks and Montgomery Counties, southeastern Pennsylvania, concentrations of arsenic and fluoride above USEPA drinking-water standards of 10 ?g/L and 4 mg/L, respectively, and of boron above the USEPA health advisory level of 600 ?g/L were measured in ground water in an area along the northwestern edge of the Newark Basin. In 2003, the USEPA requested technical assistance from the U.S. Geological Survey (USGS) to help identify sources of arsenic, boron, and fluoride in the ground water in the Congo Road area, which included possible anthropogenic releases and naturally occurring mineralization in the local bedrock aquifer, and to identify other areas in the Newark Basin of southeastern Pennsylvania with similarly elevated concentrations of these constituents. The USGS reviewed available data and collected additional ground-water samples in the Congo Road area and four similar hydrogeologic settings. The Newark Basin is the largest of the 13 major exposed Mesozoic rift basins that stretch from Nova Scotia to South Carolina. Rocks in the Newark Basin include Triassic through Jurassic-age sedimentary sequences of sandstones and shales that were intruded by diabase. Mineral deposits of hydrothermal origin are associated with alteration zones bordering intrusions of diabase and also occur as strata-bound replacement deposits of copper and zinc in sedimentary rocks. The USGS review of data available in 2003 showed that water from about 10 percent of wells throughout the Newark Basin of southeastern Pennsylvania had concentrations of arsenic greater than the USEPA maximum contaminant level (MCL) of 10 ?g/L; the highest reported arsenic concentration was at about 70 ?g/L. Few data on boron were available, and the highest reported boron concentration in well-water samples was 60 ?g/L in contrast

  9. Changes in relative and absolute concentrations of plasma phospholipid fatty acids observed in a randomized trial of Omega-3 fatty acids supplementation in Uganda.

    Science.gov (United States)

    Song, Xiaoling; Diep, Pho; Schenk, Jeannette M; Casper, Corey; Orem, Jackson; Makhoul, Zeina; Lampe, Johanna W; Neuhouser, Marian L

    2016-11-01

    Expressing circulating phospholipid fatty acids (PLFAs) in relative concentrations has some limitations: the total of all fatty acids are summed to 100%; therefore, the values of individual fatty acid are not independent. In this study we examined if both relative and absolute metrics could effectively measure changes in circulating PLFA concentrations in an intervention trial. 66 HIV and HHV8 infected patients in Uganda were randomized to take 3g/d of either long-chain omega-3 fatty acids (1856mg EPA and 1232mg DHA) or high-oleic safflower oil in a 12-week double-blind trial. Plasma samples were collected at baseline and end of trial. Relative weight percentage and absolute concentrations of 41 plasma PLFAs were measured using gas chromatography. Total cholesterol was also measured. Intervention-effect changes in concentrations were calculated as differences between end of 12-week trial and baseline. Pearson correlations of relative and absolute concentration changes in individual PLFAs were high (>0.6) for 37 of the 41 PLFAs analyzed. In the intervention arm, 17 PLFAs changed significantly in relative concentration and 16 in absolute concentration, 15 of which were identical. Absolute concentration of total PLFAs decreased 95.1mg/L (95% CI: 26.0, 164.2; P=0.0085), but total cholesterol did not change significantly in the intervention arm. No significant change was observed in any of the measurements in the placebo arm. Both relative weight percentage and absolute concentrations could effectively measure changes in plasma PLFA concentrations. EPA and DHA supplementation changes the concentrations of multiple plasma PLFAs besides EPA and DHA.Both relative weight percentage and absolute concentrations could effectively measure changes in plasma phospholipid fatty acid (PLFA) concentrations. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Absolute concentration determination of phosphorus metabolites in the Langendorff-perfused rabbit heart by phosphorus-31 nuclear magnetic resonance

    International Nuclear Information System (INIS)

    Gard, J.K.

    1984-01-01

    The concentrations of mobile high energy phosphorus metabolites and intracellular pH of Langendorff-perfused rabbit heart have been determined under control and reduced flow conditions. Absolute concentration determination was accomplished by Lorentzian lineshape analysis after development of hexachlorocyclotriphosphazene as an external intensity standard. Hearts were demonstrated to be biochemically and physiologically competent during control perfusion periods and compromised during reduced flow conditions by independent hemodynamic and metabolic measurements coincident with the NMR experiment. Reduction in perfusate flow from 20 mL/min to 5.0 mL/min (25% flow) or 2.5 mL/min (12.5% flow) demonstrated a fall in phosphocreatine and adenosine triphosphate concentrations, a rise in cytosolic inorganic phosphate concentrations, and drops in pH. Subsequent recovery upon reflow was observed. The derived values for the free concentration of ADP were very close to the reported values of the Michaelis constant for respiratory stimulation, implicating a regulatory role for this molecule in cellular respiration. Strong evidence that the creating kinase reaction was in equilibrium in the 25% flow study was seen. The NMR observable correlated closely with myocardial performance and biochemical indices of metabolic function, and supported the use of phosphocreatine as an indicator of current metabolic integrity

  11. Monitoring of blood-10B concentration for boron neutron capture therapy using prompt gamma-ray analysis

    International Nuclear Information System (INIS)

    Raaijmakers, C.P.J.; Konijnenberg, M.W.; Dewit, L.; Mijnheer, B.J.; Haritz, D.; Huiskamp, R.; Philipp, K.; Siefert, A.; Stecher-Rasmussen, F.

    1995-01-01

    The aim of the present study was to monitor the blood- 10 B concentration of laboratory dogs receiving boron neutron capture therapy, in order to obtain optimal agreement between prescribed and actual dose. A prompt gamma-ray analysis system was developed for this purpose at the High Flux Reactor in Petten. The technique was compared with inductively coupled plasma-atomic emission spectrometry and showed good agreement. A substantial variation in 10 B clearance pattern after administration of borocaptate sodium was found between the different dogs. Consequently, the irradiation commencement was adjusted to the individually determined boron elimination curve. Mean blood- 10 B concentratios during irradiation of 25.8±2.2 μg/g (1 SD, n=18) and 49.3±5.3 μg/g (1 SD, n=17) were obtained for intended concentrations of 25 μg/g and 50 μg/g, respectively. These variations are a factor of two smaller than irradiations performed at a uniform post-infusion irradiation starting time. Such a careful bolld- 10 B monitoring procedure is a prerequisite for accurately obtaining such steep dose-response curves as observed during the dog study. (orig.)

  12. Investigations of different doping concentration of phosphorus and boron into silicon substrate on the variable temperature Raman characteristics

    Science.gov (United States)

    Li, Xiaoli; Ding, Kai; Liu, Jian; Gao, Junxuan; Zhang, Weifeng

    2018-01-01

    Different doped silicon substrates have different device applications and have been used to fabricate solar panels and large scale integrated circuits. The thermal transport in silicon substrates are dominated by lattice vibrations, doping type, and doping concentration. In this paper, a variable-temperature Raman spectroscopic system is applied to record the frequency and linewidth changes of the silicon peak at 520 cm-1 in five chips of silicon substrate with different doping concentration of phosphorus and boron at the 83K to 1473K temperature range. The doping has better heat sensitive to temperature on the frequency shift over the low temperature range from 83K to 300K but on FWHM in high temperature range from 300K to 1473K. The results will be helpful for fundamental study and practical applications of silicon substrates.

  13. A non-invasive diffuse reflectance calibration-free method for absolute determination of exogenous biochemicals concentration in biological tissues

    Science.gov (United States)

    Lappa, Alexander V.; Kulikovskiy, Artem N.; Busarov, Oleg G.

    2014-03-01

    The paper presents a new method for distant non-destructive determination of concentration of light absorbing admixtures in turbid media. In particular, it is intended for non-invasive in vivo control of accumulation in patient tissues of various biochemicals introduced to the patients for chemotherapy, photodynamic therapy or diagnostics. It is require that the admixture absorption spectrum should have a clearly marked peak in the wavelength region where the pure medium one varies regularly. Fluorescence of admixtures is not required. The method uses the local diffuse reflectance spectroscopy with optical fiber probe including one emitting and two reading There are several features in the method: the value to be determined is absolute concentration of admixtures; the method needs no calibration measurements on phantoms; it needs no reference measurements on sample with zero admixture concentration; it uses a two parametric kinetic light propagation model and original algorithms to resolve direct and inverse tasks of radiation transport theory. Experimental testing passed with tissue equivalent phantoms and different admixtures, including a chlorine photosensitizer, showed accuracy under 10% in all cases.

  14. PET pharmacokinetic analysis to estimate boron concentration in tumor and brain as a guide to plan BNCT for malignant cerebral glioma

    Energy Technology Data Exchange (ETDEWEB)

    Nariai, Tadashi [Department of Neurosurgery, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo (Japan)], E-mail: nariai.nsrg@tmd.ac.jp; Ishiwata, Kiichi [Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, 1-1, Nakacho, Itabashi-ku, Tokyo (Japan); Kimura, Yuichi [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba (Japan); Inaji, Motoki; Momose, Toshiya [Department of Neurosurgery, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo (Japan); Yamamoto, Tetsuya; Matsumura, Akira [Department of Neurosurgery, University of Tsukuba, Tennodai, Tsukuba, Igaraki (Japan); Ishii, Kenji [Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, 1-1, Nakacho, Itabashi-ku, Tokyo (Japan); Ohno, Kikuo [Department of Neurosurgery, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo (Japan)

    2009-07-15

    Introduction: To plan the optimal BNCT for patients with malignant cerebral glioma, estimation of the ratio of boron concentration in tumor tissue against that in the surrounding normal brain (T/N ratio of boron) is important. We report a positron emission tomography (PET) imaging method to estimate T/N ratio of tissue boron concentration based on pharmacokinetic analysis of amino acid probes. Methods: Twelve patients with cerebral malignant glioma underwent 60 min dynamic PET scanning of brain after bolus injection of {sup 18}F-borono-phenyl-alanine (FBPA) with timed arterial blood sampling. Using kinetic parameter obtained by this scan, T/N ratio of boron concentration elicited by one-hour constant infusion of BPA, as performed in BNCT, was simulated on Runge-Kutta algorithm. {sup 11}C-methionine (MET) PET scan, which is commonly used in worldwide PET center as brain tumor imaging tool, was also performed on the same day to compare the image characteristics of FBPA and that of MET. Result: PET glioma images obtained with FBPA and MET are almost identical in all patients by visual inspection. Estimated T/N ratio of tissue boron concentration after one-hour constant infusion of BPA, T/N ratio of FBPA on static condition, and T/N ratio of MET on static condition showed significant linear correlation between each other. Conclusion: T/N ratio of boron concentration that is obtained by constant infusion of BPA during BNCT can be estimated by FBPA PET scan. This ratio can also be estimated by MET-PET imaging. As MET-PET study is available in many clinical PET center, selection of candidates for BNCT may be possible by MET-PET images. Accurate planning of BNCT may be performed by static images of FBPA PET. Use of PET imaging with amino acid probes may contribute very much to establish an appropriate application of BNCT for patients with malignant glioma.

  15. PET pharmacokinetic analysis to estimate boron concentration in tumor and brain as a guide to plan BNCT for malignant cerebral glioma

    International Nuclear Information System (INIS)

    Nariai, Tadashi; Ishiwata, Kiichi; Kimura, Yuichi; Inaji, Motoki; Momose, Toshiya; Yamamoto, Tetsuya; Matsumura, Akira; Ishii, Kenji; Ohno, Kikuo

    2009-01-01

    Introduction: To plan the optimal BNCT for patients with malignant cerebral glioma, estimation of the ratio of boron concentration in tumor tissue against that in the surrounding normal brain (T/N ratio of boron) is important. We report a positron emission tomography (PET) imaging method to estimate T/N ratio of tissue boron concentration based on pharmacokinetic analysis of amino acid probes. Methods: Twelve patients with cerebral malignant glioma underwent 60 min dynamic PET scanning of brain after bolus injection of 18 F-borono-phenyl-alanine (FBPA) with timed arterial blood sampling. Using kinetic parameter obtained by this scan, T/N ratio of boron concentration elicited by one-hour constant infusion of BPA, as performed in BNCT, was simulated on Runge-Kutta algorithm. 11 C-methionine (MET) PET scan, which is commonly used in worldwide PET center as brain tumor imaging tool, was also performed on the same day to compare the image characteristics of FBPA and that of MET. Result: PET glioma images obtained with FBPA and MET are almost identical in all patients by visual inspection. Estimated T/N ratio of tissue boron concentration after one-hour constant infusion of BPA, T/N ratio of FBPA on static condition, and T/N ratio of MET on static condition showed significant linear correlation between each other. Conclusion: T/N ratio of boron concentration that is obtained by constant infusion of BPA during BNCT can be estimated by FBPA PET scan. This ratio can also be estimated by MET-PET imaging. As MET-PET study is available in many clinical PET center, selection of candidates for BNCT may be possible by MET-PET images. Accurate planning of BNCT may be performed by static images of FBPA PET. Use of PET imaging with amino acid probes may contribute very much to establish an appropriate application of BNCT for patients with malignant glioma.

  16. 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.

  17. Electrochemical oxidation of tramadol in low-salinity reverse osmosis concentrates using boron-doped diamond anodes.

    Science.gov (United States)

    Lütke Eversloh, Christian; Schulz, Manoj; Wagner, Manfred; Ternes, Thomas A

    2015-04-01

    The electrochemical treatment of low-salinity reverse osmosis (RO) concentrates was investigated using tramadol (100 μM) as a model substance for persistent organic contaminants. Galvanostatic degradation experiments using boron-doped diamond electrodes at different applied currents were conducted in RO concentrates as well as in ultra-pure water containing either sodium chloride or sodium sulfate. Kinetic investigations revealed a significant influence of in-situ generated active chlorine besides direct anodic oxidation. Therefore, tramadol concentrations decreased more rapidly at elevated chloride content. Nevertheless, reduction of total organic carbon (TOC) was found to be comparatively low, demonstrating that transformation rather than mineralization was taking place. Early stage product formation could be attributed to both direct and indirect processes, including demethylation, hydroxylation, dehydration, oxidative aromatic ring cleavage and halogenation reactions. The latter led to various halogenated derivatives and resulted in AOX (adsorbable organic halogens) formation in the lower mg/L-range depending on the treatment conditions. Characterisation of transformation products (TPs) was achieved via MS(n) experiments and additional NMR measurements. Based on identification and quantification of the main TPs in different matrices and on additional potentiostatic electrolysis, a transformation pathway was proposed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Electrochemical treatment of reverse osmosis concentrate on boron-doped electrodes in undivided and divided cell configurations.

    Science.gov (United States)

    Bagastyo, Arseto Y; Batstone, Damien J; Kristiana, Ina; Escher, Beate I; Joll, Cynthia; Radjenovic, Jelena

    2014-08-30

    An undivided electrolytic cell may offer lower electrochlorination through reduction of chlorine/hypochlorite at the cathode. This study investigated the performance of electrooxidation of reverse osmosis concentrate using boron-doped diamond electrodes in membrane-divided and undivided cells. In both cell configurations, similar extents of chemical oxygen demand and dissolved organic carbon removal were obtained. Continuous formation of chlorinated organic compounds was observed regardless of the membrane presence. However, halogenation of the organic matter did not result in a corresponding increase in toxicity (Vibrio fischeri bioassay performed on extracted samples), with toxicity decreasing slightly until 10AhL(-1), and generally remaining near the initial baseline-toxicity equivalent concentration (TEQ) of the raw concentrate (i.e., ∼2mgL(-1)). The exception was a high range toxicity measure in the undivided cell (i.e., TEQ=11mgL(-1) at 2.4AhL(-1)), which rapidly decreased to 4mgL(-1). The discrepancy between the halogenated organic matter and toxicity patterns may be a consequence of volatile and/or polar halogenated by-products formed in oxidation by OH electrogenerated at the anode. The undivided cell exhibited lower energy compared to the divided cell, 0.25kWhgCOD(-1) and 0.34kWhgCOD(-1), respectively, yet it did not demonstrate any improvement regarding by-products formation. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. High arsenic and boron concentrations in groundwaters related to mining activity in the Bigadic borate deposits (Western Turkey)

    International Nuclear Information System (INIS)

    Gemici, Unsal; Tarcan, Gueltekin; Helvaci, Cahit; Somay, A. Melis

    2008-01-01

    This study documents the environmental impacts of borate mines in Bigadic district, which are the largest colemanite and ulexite deposits in the world. Borate-bearing formations have affected the concentrations of some contaminants in groundwater. Groundwater quality is directly related to the borate zones in the mines as a result of water-rock interaction processes. Calcium is the dominant cation and waters are Ca-SO 4 and HCO 3 type in the mine (Tuelue borate mine) from which colemanite is produced. However in the Simav and Acep Borate Mines, ulexite and colemanite minerals are produced and waters from these open pit mines are Na-HCO 3 -SO 4 types. High SO 4 concentrations (reaching 519 mg/L) might be explained by the existence of anhydrite, gypsum and celestite minerals in the borate zone. Groundwater from tuff and borate strata showed relatively low pH values (7-8) compared to surface and mine waters (>8). EC values ranged from 270 to 2850 μS/cm. Boron and As were the two important contaminants determined in the groundwaters around the Bigadic borate mines. Arsenic is the major pollutant and it ranged from 33 to 911 μg/L in the groundwater samples. The concentrations of B in the study area ranged from 0.05 to 391 mg/L. The highest B concentrations were detected at the mine areas. The extension of the borate zones in the aquifer systems is the essential factor in the enrichment of B and As, and some major and trace elements in groundwaters are directly related to the leaching of the host rock which are mainly composed of tuffs and limestones. According to drinking water standards, all of the samples exceed the tolerance limit for As. Copper, Mn, Zn and Li values are enriched but do not exceed the drinking water standards. Sulfate, Al and Fe concentrations are above the drinking water standard for the groundwater samples

  20. 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

  1. Electrochemical treatment of reverse osmosis concentrate on boron-doped electrodes in undivided and divided cell configurations

    Energy Technology Data Exchange (ETDEWEB)

    Bagastyo, Arseto Y. [Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072 (Australia); Department of Environmental Engineering, Institut Teknologi Sepuluh Nopember, Surabaya 60111 (Indonesia); Batstone, Damien J. [Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072 (Australia); Kristiana, Ina [Curtin Water Quality Research Centre, Resources and Chemistry Precinct, Department of Chemistry, Curtin University, Bentley, Perth, WA 6102 (Australia); Escher, Beate I. [National Research Centre for Environmental Toxicology (Entox), The University of Queensland, Brisbane, QLD 4108 (Australia); Joll, Cynthia [Curtin Water Quality Research Centre, Resources and Chemistry Precinct, Department of Chemistry, Curtin University, Bentley, Perth, WA 6102 (Australia); Radjenovic, Jelena, E-mail: j.radjenovic@uq.edu.au [Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072 (Australia)

    2014-08-30

    Highlights: • 100% of COD and ∼70% of DOC was removed in both cell configurations. • ∼21.7 mg L{sup −1} of AOCl and ∼2.3 mg L{sup −1} of AOBr was formed regardless of the membrane use. • The TEQ was far lower than expected given the high AOCl concentrations. • The undivided cell consumed lower energy compared to the divided cell. - Abstract: An undivided electrolytic cell may offer lower electrochlorination through reduction of chlorine/hypochlorite at the cathode. This study investigated the performance of electrooxidation of reverse osmosis concentrate using boron-doped diamond electrodes in membrane-divided and undivided cells. In both cell configurations, similar extents of chemical oxygen demand and dissolved organic carbon removal were obtained. Continuous formation of chlorinated organic compounds was observed regardless of the membrane presence. However, halogenation of the organic matter did not result in a corresponding increase in toxicity (Vibrio fischeri bioassay performed on extracted samples), with toxicity decreasing slightly until 10 Ah L{sup −1}, and generally remaining near the initial baseline-toxicity equivalent concentration (TEQ) of the raw concentrate (i.e., ∼2 mg L{sup −1}). The exception was a high range toxicity measure in the undivided cell (i.e., TEQ = 11 mg L{sup −1} at 2.4 Ah L{sup −1}), which rapidly decreased to 4 mg L{sup −1}. The discrepancy between the halogenated organic matter and toxicity patterns may be a consequence of volatile and/or polar halogenated by-products formed in oxidation by OH· electrogenerated at the anode. The undivided cell exhibited lower energy compared to the divided cell, 0.25 kWh gCOD{sup −1} and 0.34 kWh gCOD{sup −1}, respectively, yet it did not demonstrate any improvement regarding by-products formation.

  2. Absolute measurement of cerebral optical coefficients, hemoglobin concentration and oxygen saturation in old and young adults with near-infrared spectroscopy

    Science.gov (United States)

    We present near-infrared spectroscopy measurement of absolute cerebral hemoglobin concentration and saturation in a large sample of 36 healthy elderly (mean age, 85 ± 6 years) and 19 young adults (mean age, 28 ± 4 years). Non-invasive measurements were obtained on the forehead using a commercially a...

  3. Boron concentration evolution in the temporary curtains of a BWR reactor. Burcur code

    International Nuclear Information System (INIS)

    Cano Aguado, M.; Perlado Martin, J.M.; Minguez Torres, E.

    1977-01-01

    The theoretical model and the user's guide of the code Burcur is included. This code analyzes the burnable poison concentration of the temporary curtains as a function of time, for BWR reactors of the 7 x 7 design. The computing time being reasonably short, the number of burnup steps is as high as necessary.(author) [es

  4. Determining the boron concentration during long-term cooling of the reactor core after large loss of coolant accident; Dolocenje koncentracij bora pri dolgotrajnoem hladjenju sredice po veliki izlivni nezgodi

    Energy Technology Data Exchange (ETDEWEB)

    Mavko, B; Ravnki, M [Institut Jozef Stefan, Ljubljana (Yugoslavia)

    1988-07-01

    Critical boron concentration before and after postulated loss of coolant accident with long-term cooling recirculation was calculated for cycle 6 of Krsko NPP. The limiting boron concentration curve of containment sump was calculated for equilibrium conditions. The results were analysed and showed that the boron concentration in refueling water storage tank and in safety injection accumulators should be increased from 2000 to 2100 ppm in 6th cycle. In the consequence corresponding chapters of the NPP Krsko technical Specifications were changed as well. (author)

  5. Boron Neutron Capture Therapy (BCNT) for the Treatment of Liver Metastases: Biodistribution Studies of Boron Compounds in an Experimental Model

    Energy Technology Data Exchange (ETDEWEB)

    Marcela A. Garabalino; Andrea Monti Hughes; Ana J. Molinari; Elisa M. Heber; Emiliano C. C. Pozzi; Maria E. Itoiz; Veronica A. Trivillin; Amanda E. Schwint; Jorge E. Cardoso; Lucas L. Colombo; Susana Nievas; David W. Nigg; Romina F. Aromando

    2011-03-01

    Abstract We previously demonstrated the therapeutic efficacy of different boron neutron capture therapy (BNCT) protocols in an experimental model of oral cancer. BNCT is based on the selective accumulation of 10B carriers in a tumor followed by neutron irradiation. Within the context of exploring the potential therapeutic efficacy of BNCT for the treatment of liver metastases, the aim of the present study was to perform boron biodistribution studies in an experimental model of liver metastases in rats. Different boron compounds and administration conditions were assayed to determine which administration protocols would potentially be therapeutically useful in in vivo BNCT studies at the RA-3 nuclear reactor. A total of 70 BDIX rats were inoculated in the liver with syngeneic colon cancer cells DHD/K12/TRb to induce the development of subcapsular tumor nodules. Fourteen days post-inoculation, the animals were used for biodistribution studies. We evaluated a total of 11 administration protocols for the boron compounds boronophenylalanine (BPA) and GB-10 (Na210B10H10), alone or combined at different dose levels and employing different administration routes. Tumor, normal tissue, and blood samples were processed for boron measurement by atomic emission spectroscopy. Six protocols proved potentially useful for BNCT studies in terms of absolute boron concentration in tumor and preferential uptake of boron by tumor tissue. Boron concentration values in tumor and normal tissues in the liver metastases model show it would be feasible to reach therapeutic BNCT doses in tumor without exceeding radiotolerance in normal tissue at the thermal neutron facility at RA-3.

  6. 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.

  7. Absolute advantage

    NARCIS (Netherlands)

    J.G.M. van Marrewijk (Charles)

    2008-01-01

    textabstractA country is said to have an absolute advantage over another country in the production of a good or service if it can produce that good or service using fewer real resources. Equivalently, using the same inputs, the country can produce more output. The concept of absolute advantage can

  8. Boron neutron capture therapy of glioblastoma multiforme using the p- boronophenylalanine-fructose complex and epithermal neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Coderre, J.A.; Chanana, A.D.; Joel, D.D.; Liu, H.B.; Slatkin, D.N.; Wielopolski, L. [Brookhaven National Lab., Upton, NY (United States); Bergland, R.; Elowitz, E. [Beth Israel Medical Center, New York, NY (United States). Dept. of Neurosurgery; Chadha, M. [Beth Israel Medical Center, New York, NY (United States). Dept. of Radiation Oncology

    1994-12-31

    The amino acid analogue p-boronophenylalanine (BPA) is under investigation as a neutron capture agent for BNCT of glioblastoma multiforme. A series of patients undergoing surgical removal of tumor received BPA orally as the free amino acid. Favorable tumor/blood boron concentration ratios were obtained but the absolute amount of boron in the tumor would have been insufficient for BNCT. BPA can be solubilized at neutral pH by complexation with fructose (BPA-F). Studies with rats suggest that intraperitoneal injection of BPA-F complex produces a much higher tumor boron concentration to rat intracerebral 9L gliosarcoma that were possible with oral BPA. Higher boron concentrations have allowed higher tumor radiation doses to be delivered while maintaining the dose to the normal brain vascular endothelium below the threshold of tolerance. The experience to date of the administration of BPA-F to one patient is provided in this report.

  9. Boron neutron capture therapy of glioblastoma multiforme using the p- boronophenylalanine-fructose complex and epithermal neutrons

    International Nuclear Information System (INIS)

    Coderre, J.A.; Chanana, A.D.; Joel, D.D.; Liu, H.B.; Slatkin, D.N.; Wielopolski, L.; Bergland, R.; Elowitz, E.; Chadha, M.

    1994-01-01

    The amino acid analogue p-boronophenylalanine (BPA) is under investigation as a neutron capture agent for BNCT of glioblastoma multiforme. A series of patients undergoing surgical removal of tumor received BPA orally as the free amino acid. Favorable tumor/blood boron concentration ratios were obtained but the absolute amount of boron in the tumor would have been insufficient for BNCT. BPA can be solubilized at neutral pH by complexation with fructose (BPA-F). Studies with rats suggest that intraperitoneal injection of BPA-F complex produces a much higher tumor boron concentration to rat intracerebral 9L gliosarcoma that were possible with oral BPA. Higher boron concentrations have allowed higher tumor radiation doses to be delivered while maintaining the dose to the normal brain vascular endothelium below the threshold of tolerance. The experience to date of the administration of BPA-F to one patient is provided in this report

  10. 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

  11. The effects of boron supplementation of layer diets varying in calcium and phosphorus concentrations on performance, egg quality, bone strength and mineral constituents of serum, bone and faeces.

    Science.gov (United States)

    Küçükyilmaz, K; Erkek, R; Bozkurt, M

    2014-01-01

    1. A 2 × 3 factorial arrangement of treatments was used to investigate the effects of dietary calcium (Ca), phosphorus (P), and supplemental boron (B) (0, 75, and 150 mg/kg) on the performance, egg quality, bone strength, and mineral constituents in bone, serum and faeces. 2. A reduction by 18% in the dietary Ca-P concentration from the recommended levels for the hen strain reduced (P properties did not corroborate the hypothesis that B is a trace element playing an important role in mineral metabolism and bone strength through an interaction with Ca, P and Mg.

  12. 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

  13. NADH-fluorescence scattering correction for absolute concentration determination in a liquid tissue phantom using a novel multispectral magnetic-resonance-imaging-compatible needle probe

    Science.gov (United States)

    Braun, Frank; Schalk, Robert; Heintz, Annabell; Feike, Patrick; Firmowski, Sebastian; Beuermann, Thomas; Methner, Frank-Jürgen; Kränzlin, Bettina; Gretz, Norbert; Rädle, Matthias

    2017-07-01

    In this report, a quantitative nicotinamide adenine dinucleotide hydrate (NADH) fluorescence measurement algorithm in a liquid tissue phantom using a fiber-optic needle probe is presented. To determine the absolute concentrations of NADH in this phantom, the fluorescence emission spectra at 465 nm were corrected using diffuse reflectance spectroscopy between 600 nm and 940 nm. The patented autoclavable Nitinol needle probe enables the acquisition of multispectral backscattering measurements of ultraviolet, visible, near-infrared and fluorescence spectra. As a phantom, a suspension of calcium carbonate (Calcilit) and water with physiological NADH concentrations between 0 mmol l-1 and 2.0 mmol l-1 were used to mimic human tissue. The light scattering characteristics were adjusted to match the backscattering attributes of human skin by modifying the concentration of Calcilit. To correct the scattering effects caused by the matrices of the samples, an algorithm based on the backscattered remission spectrum was employed to compensate the influence of multiscattering on the optical pathway through the dispersed phase. The monitored backscattered visible light was used to correct the fluorescence spectra and thereby to determine the true NADH concentrations at unknown Calcilit concentrations. Despite the simplicity of the presented algorithm, the root-mean-square error of prediction (RMSEP) was 0.093 mmol l-1.

  14. Crystal structure and composition of BAlN thin films: Effect of boron concentration in the gas flow

    KAUST Repository

    Wang, Shuo; Li, Xiaohang; Fischer, Alec M.; Detchprohm, Theeradetch; Dupuis, Russell D.; Ponce, Fernando A.

    2017-01-01

    We have investigated the microstructure of BxAl1-xN films grown by flow-modulated epitaxy at 1010 oC, with B/(B+Al) gas-flow ratios ranging from 0.06 to 0.18. The boron content obtained from X-ray diffraction (XRD) patterns ranges from x = 0.02 to 0.09. On the other hand, boron content deduced from the aluminum signal in the Rutherford backscattering spectra (RBS) ranges x = 0.06 to 0.16, closely following gas-flow ratios. Transmission electron microscopy indicates the sole presence of wurtzite crystal structure in the BAlN films, and a tendency towards columnar growth for B/(B+Al) gas-flow ratios below 0.12. For higher ratios, the BAlN films exhibit a tendency towards twin formation and finer microstructure. Electron energy loss spectroscopy has been used to profile spatial variations in the composition of the films.The RBS data suggest that the incorporation of B is highly efficient for our growth method, while the XRD data indicate that the epitaxial growth may be limited by a solubility limit in the crystal phase at about 9%, for the range of B/(B+Al) gas-flow ratios that we used, which is significantly higher than previously thought.

  15. Crystal structure and composition of BAlN thin films: Effect of boron concentration in the gas flow

    KAUST Repository

    Wang, Shuo

    2017-07-20

    We have investigated the microstructure of BxAl1-xN films grown by flow-modulated epitaxy at 1010 oC, with B/(B+Al) gas-flow ratios ranging from 0.06 to 0.18. The boron content obtained from X-ray diffraction (XRD) patterns ranges from x = 0.02 to 0.09. On the other hand, boron content deduced from the aluminum signal in the Rutherford backscattering spectra (RBS) ranges x = 0.06 to 0.16, closely following gas-flow ratios. Transmission electron microscopy indicates the sole presence of wurtzite crystal structure in the BAlN films, and a tendency towards columnar growth for B/(B+Al) gas-flow ratios below 0.12. For higher ratios, the BAlN films exhibit a tendency towards twin formation and finer microstructure. Electron energy loss spectroscopy has been used to profile spatial variations in the composition of the films.The RBS data suggest that the incorporation of B is highly efficient for our growth method, while the XRD data indicate that the epitaxial growth may be limited by a solubility limit in the crystal phase at about 9%, for the range of B/(B+Al) gas-flow ratios that we used, which is significantly higher than previously thought.

  16. 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

  17. Determination of the absolute concentrations of H2O - D2O mixtures using the increase in sensitivity of infra-red absorption measurements

    International Nuclear Information System (INIS)

    Ceccaldi, M.

    1964-01-01

    A description is given in this report of original work concerning an infrared method for determining the absolute isotopic content of H 2 O - D 2 O mixtures. The spectrum is obtained, in both the liquid and the solid states, of water of unknown D 2 O content and of mixtures of this water and light water. The Beer-Lambert law-is Well followed in this case; the measurement of three parameters involved in this law is described together with a method of measuring the fourth parameter. The results obtained using infrared and nuclear resonance techniques are compared. The concentration of the 99.9960 per cent reference water is known with a precision of a least + 40 ppm - 20 ppm and very likely to ± 5 ppm. (author) [fr

  18. Contamination of the ground waters and surface waters by boron in Lerma Valley, NW-Argentina - an inventory

    International Nuclear Information System (INIS)

    Bundschuh, J.

    1992-01-01

    Ground- and surface waters in areas unaffected by pollution from borax and boric acid producing plants exhibit low boron concentrations of less than 300 μg B/l. Only at the boric acid plant 'Mineratea' is the groundwater contaminated, with up to 6200 μg B/l occurring within an area of 8 to 10 km 2 with more than 1000 μg boron/l. Even higher boron concentrations (up to 18 μg B/l) are present in polluted surface waters. Not the boron concentration in the irrigation water, but the absolute amount of boron added to the plants by irrigation is what determines plant toxicity. For the contaminated area of the boric acid 'Mineratea', characterized by boron concentrations of between 1000 and 6000 μg B/l, the maximal amounts of irrigation water that can be applied lies between 300 and 8 mm. In order to protect the local groundwater resoures from present and future contamination, environmental impact assessment on industrial projects in the area are required. In this way, the quality of the drinking and irrigation water can be guaranteed through suitable measures, without hindering further necessary industrial development of the region. (orig./UWA) [de

  19. Mechanism of regional enrichment of groundwater by boron: the examples of Bangladesh and Michigan, USA

    International Nuclear Information System (INIS)

    Ravenscroft, P.; McArthur, J.M.

    2004-01-01

    In Bangladesh, concentrations of boron in groundwater reach 2.1 mg L -1 and are high regionally in alluvial aquifers of Late Pleistocene/Holocene age. Concentrations exceed 0.5 mg L -1 across approximately 6700 km 2 of the deep aquifer (>150 m depth) and 3000 km 2 of the shallow aquifer ( -1 and high values are widespread in the NE of the county. These concentrations exceed the regulatory guideline values for human consumption of 0.5 mg L -1 (WHO) or 0.9 mg L -1 (USA). The boron has desorbed from mineral surfaces as freshwater flushing displaces saline waters from the aquifers. In Bangladesh, desorption is driven by decreasing ionic strength, the equilibrium re-adjustment of mineral sorption sites to the low boron concentration in freshwater, and competitive exchange with HCO 3 /CO 3 . In deep Bangladesh aquifers in Barisal District (>250 m deep), boron enrichment delineates a buried estuary marking a previous course of the Ganges and/or Brahmaputra rivers. Boron enrichment is accompanied by ion-exchange that depletes Ca and enriches Na in the flushing freshwater. The patterns of enrichment and depletion indicate the direction of water quality change, in terms of salinization or freshening, with greater sensitivity than absolute chemical parameters

  20. A development and integration of the concentration database for relative method, k0 method and absolute method in instrumental neutron activation analysis using Microsoft Access

    International Nuclear Information System (INIS)

    Hoh Siew Sin

    2012-01-01

    Instrumental Neutron Activation Analysis (INAA) is offen used to determine and calculate the concentration of an element in the sample by the National University of Malaysia, especially students of Nuclear Science Program. The lack of a database service leads consumers to take longer time to calculate the concentration of an element in the sample. This is because we are more dependent on software that is developed by foreign researchers which are costly. To overcome this problem, a study has been carried out to build an INAA database software. The objective of this study is to build a database software that help the users of INAA in Relative Method and Absolute Method for calculating the element concentration in the sample using Microsoft Excel 2010 and Microsoft Access 2010. The study also integrates k 0 data, k 0 Concent and k 0 -Westcott to execute and complete the system. After the integration, a study was conducted to test the effectiveness of the database software by comparing the concentrations between the experiments and in the database. Triple Bare Monitor Zr-Au and Cr-Mo-Au were used in Abs-INAA as monitor to determine the thermal to epithermal neutron flux ratio (f). Calculations involved in determining the concentration are the net peak area (N p ), the measurement time (t m ), the irradiation time (t irr ), k-factor (k), thermal to epithermal neutron flux ratio (f), the parameters of the neutron flux distribution epithermal (α) and detection efficiency (ε p ). For Com-INAA databases, reference material IAEA-375 Soil was used to calculate the concentration of elements in the sample. CRM, SRM are also used in this database. After the INAA database integration, a verification process was to examine the effectiveness of the Abs-INAA was carried out by comparing the sample concentration between the in database and the experiment. The result of the experimental concentration value of INAA database software performed with high accuracy and precision. ICC

  1. Uncertainty and minimum detectable concentrations using relative, absolute and K*0-IAEA standardization for the INAA laboratory of the ETRR-2

    International Nuclear Information System (INIS)

    Khalil, M. Y.

    2006-01-01

    Full text: The Instrumental Neutron Activation Analysis (INAA) Laboratory of Egypt Second Training and Research Reactor (ETRR-2) is increasingly requested to perform multi-element analysis to large number of samples from different origins. The INAA laboratory has to demonstrate competence by conforming to appropriate internationally and nationally accepted standards. The objective of this work is to determine the uncertainty budget and sensitivity of the INAA laboratory measurements. Concentrations of 9 elements; Mn, Na, K, Ca, Co, Cr, Fe, Rb, and Cs, were measured against a certified test sample. Relative, absolute, and Ko-IAEA standardization methods were employed and results compared. The flux was monitored using cadmium covered gold method, and multifoil (gold, nickel and zirconium) method. The combined and expanded uncertainties were estimated. Uncertainty of concentrations ranged between 2-21% depending on the standardization method used. The relative method, giving the lowest uncertainty, produced uncertainty budget between 2 and 11%. The minimum detectable concentration was the lowest for Cs ranging between 0.36 and 0.59 ppb and the highest being for K in the range of 0.32 to 8.64 ppm

  2. Development of a High-Resolution Laser Absorption Spectroscopy Method with Application to the Determination of Absolute Concentration of Gaseous Elemental Mercury in Air.

    Science.gov (United States)

    Srivastava, Abneesh; Hodges, Joseph T

    2018-05-07

    Isotope dilution-cold-vapor-inductively coupled plasma mass spectrometry (ID-CV-ICPMS) has become the primary standard for measurement of gaseous elemental mercury (GEM) mass concentration. However, quantitative mass spectrometry is challenging for several reasons including (1) the need for isotopic spiking with a standard reference material, (2) the requirement for bias-free passive sampling protocols, (3) the need for stable mass spectrometry interface design, and (4) the time and cost involved for gas sampling, sample processing, and instrument calibration. Here, we introduce a high-resolution laser absorption spectroscopy method that eliminates the need for sample-specific calibration standards or detailed analysis of sample treatment losses. This technique involves a tunable, single-frequency laser absorption spectrometer that measures isotopically resolved spectra of elemental mercury (Hg) spectra of 6 1 S 0 ← 6 3 P 1 intercombination transition near λ = 253.7 nm. Measured spectra are accurately modeled from first-principles using the Beer-Lambert law and Voigt line profiles combined with literature values for line positions, line shape parameters, and the spontaneous emission Einstein coefficient to obtain GEM mass concentration values. We present application of this method for the measurement of the equilibrium concentration of mercury vapor near room temperature. Three closed systems are considered: two-phase mixtures of liquid Hg and its vapor and binary two-phase mixtures of Hg-air and Hg-N 2 near atmospheric pressure. Within the experimental relative standard uncertainty, 0.9-1.5% congruent values of the equilibrium Hg vapor concentration are obtained for the Hg-only, Hg-air, Hg-N 2 systems, in confirmation with thermodynamic predictions. We also discuss detection limits and the potential of the present technique to serve as an absolute primary standard for measurements of gas-phase mercury concentration and isotopic composition.

  3. Effect of boron and gadolinium concentration on the calculated neutron multiplication factor of U(3)O2 fuel pins in optimum geometries

    International Nuclear Information System (INIS)

    Thomas, J.T.

    1984-10-01

    The KENO-Va improved Monte Carlo criticality program is used to calculate the neutron multiplication factor for TMI-U2 fuel compositions in a variety of configurations and to display parametric regions giving rise to maximum reactivity contributions. The lattice pitch of UO 2 fuel pins producing a maximum k/sub eff/ is determined as a function of boron concentrations in the coolant for infinite and finite systems. The characteristics of U 3 O 8 -coolant mixtures of interest to modeling the rubble region of the core are presented. Several disrupted core configurations are calculated and comparisons made. The results should be useful to proposed defueling of the TMI-U2 reactor

  4. Absolute Summ

    Science.gov (United States)

    Phillips, Alfred, Jr.

    Summ means the entirety of the multiverse. It seems clear, from the inflation theories of A. Guth and others, that the creation of many universes is plausible. We argue that Absolute cosmological ideas, not unlike those of I. Newton, may be consistent with dynamic multiverse creations. As suggested in W. Heisenberg's uncertainty principle, and with the Anthropic Principle defended by S. Hawking, et al., human consciousness, buttressed by findings of neuroscience, may have to be considered in our models. Predictability, as A. Einstein realized with Invariants and General Relativity, may be required for new ideas to be part of physics. We present here a two postulate model geared to an Absolute Summ. The seedbed of this work is part of Akhnaton's philosophy (see S. Freud, Moses and Monotheism). Most important, however, is that the structure of human consciousness, manifest in Kenya's Rift Valley 200,000 years ago as Homo sapiens, who were the culmination of the six million year co-creation process of Hominins and Nature in Africa, allows us to do the physics that we do. .

  5. 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)

  6. Influence of physical and chemical properties of HTSXT-FTIR samples on the quality of prediction models developed to determine absolute concentrations of total proteins, carbohydrates and triglycerides: a preliminary study on the determination of their absolute concentrations in fresh microalgal biomass.

    Science.gov (United States)

    Serrano León, Esteban; Coat, Rémy; Moutel, Benjamin; Pruvost, Jérémy; Legrand, Jack; Gonçalves, Olivier

    2014-11-01

    Absolute concentrations of total macromolecules (triglycerides, proteins and carbohydrates) in microorganisms can be rapidly measured by FTIR spectroscopy, but caution is needed to avoid non-specific experimental bias. Here, we assess the limits within which this approach can be used on model solutions of macromolecules of interest. We used the Bruker HTSXT-FTIR system. Our results show that the solid deposits obtained after the sampling procedure present physical and chemical properties that influence the quality of the absolute concentration prediction models (univariate and multivariate). The accuracy of the models was degraded by a factor of 2 or 3 outside the recommended concentration interval of 0.5-35 µg spot(-1). Change occurred notably in the sample hydrogen bond network, which could, however, be controlled using an internal probe (pseudohalide anion). We also demonstrate that for aqueous solutions, accurate prediction of total carbohydrate quantities (in glucose equivalent) could not be made unless a constant amount of protein was added to the model solution (BSA). The results of the prediction model for more complex solutions, here with two components: glucose and BSA, were very encouraging, suggesting that this FTIR approach could be used as a rapid quantification method for mixtures of molecules of interest, provided the limits of use of the HTSXT-FTIR method are precisely known and respected. This last finding opens the way to direct quantification of total molecules of interest in more complex matrices.

  7. A microdose study of ¹⁴C-AR-709 in healthy men: pharmacokinetics, absolute bioavailability and concentrations in key compartments of the lung.

    Science.gov (United States)

    Lappin, G; Boyce, M J; Matzow, T; Lociuro, S; Seymour, M; Warrington, S J

    2013-09-01

    To explore, in a microdose (phase-0) study, the pharmacokinetics, bioavailability and concentrations in key compartments of the lung, of AR-709, a novel diaminopyrimidine antibiotic for the treatment of respiratory infection. Four healthy men each received two single, 100 μg microdoses of ¹⁴C-AR-709, 7 days apart: the first was administered intravenously (IV), the second orally. Plasma pharmacokinetics of ¹⁴C and unchanged AR-709 were obtained by high-performance liquid chromatography and accelerator mass spectrometry (AMS). Next, 15 healthy men received a single, 100 μg microdose of ¹⁴C-AR-709 IV. Plasma, bronchoalveolar lavage fluid, alveolar macrophages and bronchial mucosal biopsy samples were analysed by AMS. After IV administration, clearance of AR-709 was 496 mL/min, volume of distribution was 1,700 L and the absolute oral bioavailability was 2.5 %. Excretion in urine was negligible. At 8-12 h after IV dosing, ¹⁴C concentrations in lung samples were 15- (bronchial mucosa) to 200- (alveolar macrophages) fold higher than in plasma. In alveolar macrophages, ¹⁴C was still mostly associated with AR-709 at 12 h after dosing. The results of this microdose study indicate that AR-709 attains concentrations appreciably higher within the lung than in plasma. Its low oral bioavailability however, precludes oral administration. Although IV administration would appear to be an effective route of administration, this would limit the use of AR-709 to a clinical setting and would therefore be economically unsustainable. If further clinical development were to be undertaken, therefore, an alternative route of administration would be necessary.

  8. 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

  9. Amelioration of boron toxicity in sweet pepper as affected by calcium management under an elevated CO2 concentration.

    Science.gov (United States)

    Piñero, María Carmen; Pérez-Jiménez, Margarita; López-Marín, Josefa; Del Amor, Francisco M

    2017-04-01

    We investigated B tolerance in sweet pepper plants (Capsicum annuun L.) under an elevated CO 2 concentration, combined with the application of calcium as a nutrient management amelioration technique. The data show that high B affected the roots more than the aerial parts, since there was an increase in the shoot/root ratio, when plants were grown with high B levels; however, the impact was lessened when the plants were grown at elevated CO 2 , since the root FW reduction caused by excess B was less marked at the high CO 2 concentration (30.9% less). Additionally, the high B concentration affected the membrane permeability of roots, which increased from 39 to 54% at ambient CO 2 concentration, and from 38 to 51% at elevated CO 2 concentration, producing a cation imbalance in plants, which was differentially affected by the CO 2 supply. The Ca surplus in the nutrient solution reduced the nutritional imbalance in sweet pepper plants produced by the high B concentration, at both CO 2 concentrations. The medium B concentration treatment (toxic according to the literature) did not result in any toxic effect. Hence, there is a need to review the literature on critical and toxic B levels taking into account increases in atmospheric CO 2 .

  10. 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)

  11. 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

  12. Artificial neural networks to evaluate the boron concentration decreasing profile in Blood-BPA samples of BNCT patients

    International Nuclear Information System (INIS)

    García-Reiriz, Alejandro; Magallanes, Jorge; Zupan, Jure; Líberman, Sara

    2011-01-01

    For the prediction of decay concentration profiles of the p-boronophenylalanine (BPA) in blood during BNCT treatment, a method is suggested based on Kohonen neural networks. The results of a model trained with the concentration profiles from the literature are described. The prediction of the model was validated by the leave-one-out method. Its robustness shows that it is mostly independent on small variations. The ability to fit retrospective experimental data shows an uncertainty lower than the two compartment model used previously. - Highlights: ► We predicted decaying concentration profiles of BPA in blood during BNCT therapy. ► Is suggested a method based on Kohonen neural networks. ► The results show that it is very robust and mostly independent of small variations. ► It has a better ability to fit retrospective experimental data. ► The model could be progressively improved by adding new data to the training matrix.

  13. EFFECTS OF IRRIGATION WATER QUALITY (DIFFERENT SALINITY LEVELS AND BORON CONCENTRATIONS ON MORPHOLOGICAL CHARACTERISTICS OF GRAFTED AND NON-GRAFTED EGGPLANTS

    Directory of Open Access Journals (Sweden)

    İsmail Taş

    2016-07-01

    Full Text Available High yield cultivars with quite high resistance against pests and diseases, irrigation water salinity and deficit irrigation conditions are significant in plant production activities. Researches have been conducted also to improve the resistance of available cultivars. Since 1990s, researchers have tried to use low quality irrigation waters just because of deficit water resources and current trends in global warming and climate change. The basic target in all these researches is to reduce production costs and to improve quality and yields. Availability of low quality irrigation waters is a basic component of sustainable agricultural production. The present study was conducted in 40 liter pots under greenhouse conditions. Grafted and non-grafted eggplant seedlings were planted into these pots. Then, plants were irrigated with irrigations waters with different salinity levels (0.25, 1, 1.5, 2, 4, 6, 10 and 15 dS/m and boron concentrations (0, 1, 2, 4, 8, 16, 32 and 64 ppm. In this way, effects of different irrigation water qualities on plant morphological characteristics were investigated.

  14. Artificial neural networks to evaluate the boron concentration decreasing profile in Blood-BPA samples of BNCT patients

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Reiriz, Alejandro, E-mail: garciareiriz@gmail.com [Department of Analytical Chemistry, Faculty of Biochemical and Pharmaceutical Sciences, National University of Rosario, Rosario Institute of Chemistry (IQUIR-CONICET), Suipacha 531, Rosario S2002LRK (Argentina); Magallanes, Jorge [Comision Nacional de Energia Atomica, Av. Gral. Paz 1499, San Martin, B1650KNA, Buenos Aires (Argentina); Zupan, Jure [National Institute of Chemistry, Hajdrihova 19, SLO-1000 Ljubljana, Eslovenia (Slovenia); Liberman, Sara [Comision Nacional de Energia Atomica, Av. Gral. Paz 1499, San Martin, B1650KNA, Buenos Aires (Argentina)

    2011-12-15

    For the prediction of decay concentration profiles of the p-boronophenylalanine (BPA) in blood during BNCT treatment, a method is suggested based on Kohonen neural networks. The results of a model trained with the concentration profiles from the literature are described. The prediction of the model was validated by the leave-one-out method. Its robustness shows that it is mostly independent on small variations. The ability to fit retrospective experimental data shows an uncertainty lower than the two compartment model used previously. - Highlights: Black-Right-Pointing-Pointer We predicted decaying concentration profiles of BPA in blood during BNCT therapy. Black-Right-Pointing-Pointer Is suggested a method based on Kohonen neural networks. Black-Right-Pointing-Pointer The results show that it is very robust and mostly independent of small variations. Black-Right-Pointing-Pointer It has a better ability to fit retrospective experimental data. Black-Right-Pointing-Pointer The model could be progressively improved by adding new data to the training matrix.

  15. Biodistribution of Boron compounds in an experimental model of liver metastases for Boron Neutron Capture (BNCT) Studies

    International Nuclear Information System (INIS)

    Garabalino, Marcela A.; Monti Hughes, Andrea; Molinari, Ana J.; Heber, Elisa M.; Pozzi, Emiliano C.C.; Itoiz, Maria E.; Trivillin, Veronica A.; Schwint, Amanda E.; Nievas, Susana; Aromando, Romina F.

    2009-01-01

    Boron Neutron Capture Therapy (BNCT) is a binary treatment modality that involves the selective accumulation of 10 B carriers in tumors followed by irradiation with thermal or epithermal neutrons. The high linear energy transfer alpha particles and recoiling 7 Li nuclei emitted during the capture of a thermal neutron by a 10 B nucleus have a short range and a high biological effectiveness. Thus, BNCT would potentially target neoplastic tissue selectively. In previous studies we demonstrated the therapeutic efficacy of different BNCT protocols in an experimental model of oral cancer. More recently we performed experimental studies in normal rat liver that evidenced the feasibility of treating liver metastases employing a novel BNCT protocol proposed by JEC based on ex-situ treatment and partial liver auto-transplant. The aim of the present study was to perform biodistribution studies with different boron compounds and different administration protocols to determine the protocols that would be therapeutically useful in 'in vivo' BNCT studies at the RA-3 Nuclear Reactor in an experimental model of liver metastases in rats. Materials and Methods. A total of 70 BDIX rats (Charles River Lab., MA, USA) were inoculated in the liver with syngeneic colon cancer cells DH/DK12/TRb (ECACC, UK) to induce the development of subcapsular metastatic nodules. 15 days post-inoculation the animals were used for biodistribution studies. A total of 11 protocols were evaluated employing the boron compounds boronophenylalanine (BPA) and GB-10 (Na 2 10 B 1 -0H 10 ), alone or combined employing different doses and administration routes. Tumor, normal tissue and blood samples were processed for boron measurement by ICP-OES. Results. Several protocols proved potentially useful for BNCT studies in terms of absolute boron concentration in tumor and preferential uptake of boron by tumor tissue, i.e. BPA 15.5 mg 10 B/kg iv + GB-10 50 mg 10 B/kg iv; BPA 46.5 mg 10 B/kg ip; BPA 46.5 mg 10 B/kg ip

  16. On elevated fluoride and boron concentrations in groundwaters associated with the Lake Saint-Martin impact structure, Manitoba

    International Nuclear Information System (INIS)

    Desbarats, Alexandre J.

    2009-01-01

    Hydrogeological investigations conducted by the Geological Survey of Canada in the Lake Saint-Martin region of Manitoba have confirmed earlier reports of naturally elevated F - and B concentrations in local groundwaters. Fluoride and B concentrations are highly correlated (r 2 = 0.905) and reach 15.1 mg/L and 8.5 mg/L, respectively. Virtually all groundwaters with F - concentrations greater than the drinking water limit of 1.5 mg/L are from wells within the Lake Saint-Martin impact structure, a 208 Ma complex crater 23 km in diameter underlying a large part of the study area. The high-F - groundwaters can be classified into two groups according to their anionic and isotopic compositions. Group I samples consist of Na-mixed anion groundwaters, with Cl greater than 100 mg/L and highly depleted 18 O compositions indicative of recharge under much cooler climatic conditions than at present. Samples belonging to this group exhibit a striking relationship to crater morphology, and are found in an arcuate belt within the southern rim of the impact structure. Group II high-F - samples consist of Na-HCO 3 -SO 4 groundwaters, with little Cl, and less depleted 18 O compositions. Samples belonging to this group are associated with groundwaters recharged locally, on a low ridge within the impact structure. This paper traces the probable source of high-F - groundwaters to phosphatic pellets in shales of the Winnipeg Formation, a regional basal clastic unit which sub-crops at shallow depth beneath the crater rim as a result of more than 200 m of structural uplift associated with the impact event. This extensive aquifer is known elsewhere in southern Manitoba for its naturally-softened groundwaters and locally elevated F - concentrations. Group I groundwaters are interpreted as discharge from the Winnipeg Formation where it abuts against crater-fill deposits. Group II high-F - groundwaters are interpreted as modern recharge from within the impact structure, displacing Group I

  17. 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

  18. Simultaneous determination of antimony and boron in beverage and dairy products by flame atomic absorption spectrometry after separation and pre-concentration by cloud-point extraction.

    Science.gov (United States)

    Altunay, Nail; Gürkan, Ramazan

    2016-01-01

    A new cloud-point extraction (CPE) method was developed for the pre-concentration and simultaneous determination of Sb(III) and B(III) by flame atomic absorption spectrometry (FAAS). The method was based on complexation of Sb(III) and B(III) with azomethine-H in the presence of cetylpyridinium chloride (CPC) as a signal-enhancing agent, and then extraction into the micellar phase of Triton X-114. Under optimised conditions, linear calibration was obtained for Sb(III) and B(III) in the concentration ranges of 0.5-180 and 2.5-600 μg l(-1) with LODs of 0.15 and 0.75 μg l(-1), respectively. Relative standard deviations (RSDs) (25 and 100 μg l(-1) of Sb(III) and B(III), n = 6) were in a range of 2.1-3.8% and 1.9-2.3%, respectively. Recoveries of spiked samples of Sb(III) and B(III) were in the range of 98-103% and 99-102%, respectively. Measured values for Sb and B in three standard reference materials were within the 95% confidence limit of the certified values. Also, the method was used for the speciation of inorganic antimony. Sb(III), Sb(V) and total Sb were measured in the presence of excess boron before and after pre-reduction with an acidic mixture of KI-ascorbic acid. The method was successfully applied to the simultaneous determination of total Sb and B in selected beverage and dairy products.

  19. EELS measurements of boron concentration profiles in p-a-Si and nip a-Si solar cells

    DEFF Research Database (Denmark)

    Van Aken, Bas B.; Duchamp, Martial; Boothroyd, Chris

    2012-01-01

    The p-type Si layer in a-Si and μc-Si solar cells on foil needs to fulfil several important requirements. The layer is necessary to create the electric field that separates the photo-generated charge carriers; the doping also increases the conductivity to conduct the photocurrent to the front......-3, using core-loss EELS combined with numerical analysis. We control the band gap and activation energy of p-a-SiC by varying the B2H6 and CH4 flow during deposition in the process chamber. We have found a linear relation between the activation energy of the dark conductivity Eact and the optical...... band gap E04. Modelling shows that the optimum efficiency in nip solar cells is obtained when the p-a-SiC band gap is slightly larger than the band gap of the absorber layer. We have assessed the potential of core-loss EELS for detecting B and C concentrations as low as 1020cm-3 in a spatially resolved...

  20. The effect of boron concentration on the structure and elastic properties of Ru-Ir alloys: first-principles calculations

    Science.gov (United States)

    Li, Xiaolong; Zhou, Zhaobo; Hu, Riming; Zhou, Xiaolong; Yu, Jie; Liu, Manmen

    2018-04-01

    The Phase stability, electronic structure, elastic properties and hardness of Ru-Ir alloys with different B concentration were investigated by first principles calculations. The calculated formation enthaplies and cohesive energies show that these compounds are all thermodynamically stable. Information on electronic structure indicates that they possess metallic characteristic and Ru-Ir-B alloys were composed of the Ru-B and Ir-B covalent bond. The elastic properties were calculated, which included bulk modulus, shear modulus, Young’s modulus, Poisson’s ratio and hardness. The calculated results reveal that the plastic of Ru-Ir-B alloys increase with the increase of the content of B atoms, but the hardness of Ru-Ir-B alloys have no substantial progress with the increase of the content of B atoms. However, it is interesting that the hardness of the Ru-Ir-B compound was improved obviously as the B content was higher than 18 atoms because of a phase structure transition.

  1. 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%.

  2. 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%

  3. 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

  4. 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%.

  5. 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.

  6. 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.

  7. 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)

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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

  13. Concentration and electrode material dependence of the voltammetric response of iodide on platinum, glassy carbon and boron-doped diamond in the room temperature ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide

    International Nuclear Information System (INIS)

    Bentley, Cameron L.; Bond, Alan M.; Hollenkamp, Anthony F.; Mahon, Peter J.; Zhang, Jie

    2013-01-01

    The electro-oxidation of iodide has been investigated as a function of concentration using steady-state microelectrode voltammetry, transient cyclic voltammetry and linear-sweep semi-integral voltammetry on platinum, glassy carbon and boron-doped diamond electrodes in the room temperature ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide. Two oxidation processes are observed on all of the investigated electrode materials, with the first being assigned to the oxidation of iodide to triiodide (confirmed by UV/visible spectroscopy) and the second being attributed to the oxidation of triiodide to iodine. Iodide oxidation is kinetically more facile on platinum compared to glassy carbon or boron-doped diamond. At elevated bulk iodide concentrations, the nucleation and growth of sparingly soluble electrogenerated iodine at the electrode surface was observed and imaged in situ using optical microscopy. The diffusion coefficient of iodide was determined to be 2.59 (±0.04) × 10 −7 cm 2 s −1 and independent of the bulk concentration of iodide. The steady-state iodide oxidation current measured at a platinum microelectrode was found to be a linear function of iodide concentration, as expected if there are no contributions from non-Stokesian mass-transport processes (electron hopping and/or Grotthuss-type exchange) under the investigated conditions

  14. 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)

  15. 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)

  16. 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.

  17. 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

  18. 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.

  19. Absolute nutrient concentration measurements in cell culture media: 1H q-NMR spectra and data to compare the efficiency of pH-controlled protein precipitation versus CPMG or post-processing filtering approaches

    Directory of Open Access Journals (Sweden)

    Luca Goldoni

    2016-09-01

    Full Text Available The NMR spectra and data reported in this article refer to the research article titled “A simple and accurate protocol for absolute polar metabolite quantification in cell cultures using q-NMR” [1]. We provide the 1H q-NMR spectra of cell culture media (DMEM after removal of serum proteins, which show the different efficiency of various precipitating solvents, the solvent/DMEM ratios, and pH of the solution. We compare the data of the absolute nutrient concentrations, measured by PULCON external standard method, before and after precipitation of serum proteins and those obtained using CPMG (Carr-Purcell-Meiboom-Gill sequence or applying post-processing filtering algorithms to remove, from the 1H q-NMR spectra, the proteins signal contribution. For each of these approaches, the percent error in the absolute value of every measurement for all the nutrients is also plotted as accuracy assessment. Keywords: 1H NMR, pH-controlled serum removal, PULCON, Accuracy, CPMG, Deconvolution

  20. Boron delivery with liposomes for boron neutron capture therapy (BNCT): biodistribution studies in an experimental model of oral cancer demonstrating therapeutic potential

    International Nuclear Information System (INIS)

    Nigg, David W.

    2012-01-01

    Boron neutron capture therapy (BNCT) combines selective accumulation of 10B carriers in tumor tissue with subsequent neutron irradiation. We previously demonstrated the therapeutic efficacy of BNCT in the hamster cheek pouch oral cancer model. Optimization of BNCT depends largely on improving boron targeting to tumor cells. Seeking to maximize the potential of BNCT for the treatment for head and neck cancer, the aim of the present study was to perform boron biodistribution studies in the oral cancer model employing two different liposome formulations that were previously tested for a different pathology, i.e., in experimental mammary carcinoma in BALB/c mice: (1) MAC: liposomes incorporating K(nido-7-CH3(CH2)15-7,8-C2B9H11) in the bilayer membrane and encapsulating a hypertonic buffer, administered intravenously at 6 mg B per kg body weight, and (2) MAC-TAC: liposomes incorporating K(nido-7-CH3(CH2)15-7,8-C2B9H11) in the bilayer membrane and encapsulating a concentrated aqueous solution of the hydrophilic species Na3 (ae-B20H17NH3), administered intravenously at 18 mg B per kg body weight. Samples of tumor, precancerous and normal pouch tissue, spleen, liver, kidney, and blood were taken at different times post-administration and processed to measure boron content by inductively coupled plasma mass spectrometry. No ostensible clinical toxic effects were observed with the selected formulations. Both MAC and MAC-TAC delivered boron selectively to tumor tissue. Absolute tumor values for MAC-TAC peaked to 66.6 ± 16.1 ppm at 48 h and to 43.9 ± 17.6 ppm at 54 h with very favorable ratios of tumor boron relative to precancerous and normal tissue, making these protocols particularly worthy of radiobiological assessment. Boron concentration values obtained would result in therapeutic BNCT doses in tumor without exceeding radiotolerance in precancerous/normal tissue at the thermal neutron facility at RA-3.

  1. Boron delivery with liposomes for boron neutron capture therapy (BNCT): biodistribution studies in an experimental model of oral cancer demonstrating therapeutic potential

    Energy Technology Data Exchange (ETDEWEB)

    David W. Nigg

    2012-05-01

    Boron neutron capture therapy (BNCT) combines selective accumulation of 10B carriers in tumor tissue with subsequent neutron irradiation. We previously demonstrated the therapeutic efficacy of BNCT in the hamster cheek pouch oral cancer model. Optimization of BNCT depends largely on improving boron targeting to tumor cells. Seeking to maximize the potential of BNCT for the treatment for head and neck cancer, the aim of the present study was to perform boron biodistribution studies in the oral cancer model employing two different liposome formulations that were previously tested for a different pathology, i.e., in experimental mammary carcinoma in BALB/c mice: (1) MAC: liposomes incorporating K[nido-7-CH3(CH2)15-7,8-C2B9H11] in the bilayer membrane and encapsulating a hypertonic buffer, administered intravenously at 6 mg B per kg body weight, and (2) MAC-TAC: liposomes incorporating K[nido-7-CH3(CH2)15-7,8-C2B9H11] in the bilayer membrane and encapsulating a concentrated aqueous solution of the hydrophilic species Na3 [ae-B20H17NH3], administered intravenously at 18 mg B per kg body weight. Samples of tumor, precancerous and normal pouch tissue, spleen, liver, kidney, and blood were taken at different times post-administration and processed to measure boron content by inductively coupled plasma mass spectrometry. No ostensible clinical toxic effects were observed with the selected formulations. Both MAC and MAC-TAC delivered boron selectively to tumor tissue. Absolute tumor values for MAC-TAC peaked to 66.6 {+-} 16.1 ppm at 48 h and to 43.9 {+-} 17.6 ppm at 54 h with very favorable ratios of tumor boron relative to precancerous and normal tissue, making these protocols particularly worthy of radiobiological assessment. Boron concentration values obtained would result in therapeutic BNCT doses in tumor without exceeding radiotolerance in precancerous/normal tissue at the thermal neutron facility at RA-3.

  2. Boron microquantification in oral mucosa and skin following administration of a neutron capture therapy agent

    International Nuclear Information System (INIS)

    Kiger, S.W. III; Micca, P.L.; Morris, G.M.; Coderre, J.A.

    2002-01-01

    Clinical trials of boron neutron capture therapy (BNCT) for intracranial tumours using boronphenylalanine-fructose undertaken at Harvard-MIT and Brookhaven National Laboratory have observed acute normal tissue reactions in the skin and oral mucosa. Because the range of the 10 B(n,a) 7 Li reaction products is very short, 10-14 μm combined, knowledge of the 10B microdistribution in tissue is critical for understanding the microdosimetry and radiobiology of BNCT. This paper reports measurements of the microdistribution of 10 B in an animal model, rat skin and tongue, using high resolution quantitative autoradiography (HRQAR), a neutron-induced track etch autoradiographic technique. The steep spatial gradient and high absolute value relative to blood of the 10 B concentration observed in some strata of the rat tongue epithelium and skin are important for properly evaluating the radiobiology and the biological effectiveness factors for normal tissue reactions such as oral mucositis, which are generally assessed using the blood boron concentration rather than the tissue boron concentration. (author)

  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. 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.

  5. Experimental investigation of the accuracy for absolute quantification of brain creatine concentration using long time echo point resolved spectroscopy sequence with an external standard and linear combination of model spectra

    International Nuclear Information System (INIS)

    Lin Yan; Shen Zhiwei; Xiao Yeyu; Zheng Wenbin; Wu Renhua; Li Hui; Xiao Zhuanwei

    2008-01-01

    Objective: To investigate the accuracy for absolute quantification of brain creatine (Cr) concentration using long time echo (TE) point resolved spectroscopy (PRESS) sequence performed with an extemal standard and postprocessed with the linear combination of model spectra ( LCModel). Methods: Ten swine (3.1 ± 0.6 kg) and an external standard phantom containing detectable compounds of known concentration were investigated in this study by using 1.5 T GE Signa scanner and a standard head coil. The single-voxel proton magnetic resonance spectroscopy ( 1 H-MRS) data were acquired from the two ROIs (2 cm x 2 cm x 2 cm) placed in swine brain and external standard solution using PRESS sequence with TE 135 ms, TR 1500 ms, and 128 scan averages. The in vivo quantification of Cr was accomplished by LCModel. After 1 H-MRS examination, each animal was sacrificed immediately. In vitro Cr concentration was analyzed by high performance liquid chromatography (HPLC). Results: In the 1 H-MRS group, the Cr concentration was (9.37±0.14)mmol/kg. In the HPLC group, the Cr concentration was (8.91± 0.13)mmol/kg. Good agreement was obtained between these two methods (t=9.038, P=0.491). Conclusion: The long echo time PRESS sequence performed with an external standard and processed with LCModel is proven to be an accurate technique to detect the in vivo brain Cr concentration. (authors)

  6. 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)

  7. Removal of boron from aqueous solution using magnesite and bentonite clay composite

    CSIR Research Space (South Africa)

    Masindi, Vhahangwele

    2015-03-01

    Full Text Available The removal of boron from industrial effluents using the composite was studied in batch equilibration technique. The effects of equilibration time, adsorbent dosage, concentration and pH on removal of boron were investigated. The experiments...

  8. Absolute nuclear material assay

    Science.gov (United States)

    Prasad, Manoj K [Pleasanton, CA; Snyderman, Neal J [Berkeley, CA; Rowland, Mark S [Alamo, CA

    2010-07-13

    A method of absolute nuclear material assay of an unknown source comprising counting neutrons from the unknown source and providing an absolute nuclear material assay utilizing a model to optimally compare to the measured count distributions. In one embodiment, the step of providing an absolute nuclear material assay comprises utilizing a random sampling of analytically computed fission chain distributions to generate a continuous time-evolving sequence of event-counts by spreading the fission chain distribution in time.

  9. 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.

  10. 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.

  11. 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.

  12. Danish Towns during Absolutism

    DEFF Research Database (Denmark)

    This anthology, No. 4 in the Danish Urban Studies Series, presents in English recent significant research on Denmark's urban development during the Age of Absolutism, 1660-1848, and features 13 articles written by leading Danish urban historians. The years of Absolutism were marked by a general...

  13. ABSOLUTE NEUTRINO MASSES

    DEFF Research Database (Denmark)

    Schechter, J.; Shahid, M. N.

    2012-01-01

    We discuss the possibility of using experiments timing the propagation of neutrino beams over large distances to help determine the absolute masses of the three neutrinos.......We discuss the possibility of using experiments timing the propagation of neutrino beams over large distances to help determine the absolute masses of the three neutrinos....

  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. 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.

  16. Differentiation in boron distribution in adult male and female rats' normal brain: A BNCT approach

    International Nuclear Information System (INIS)

    Goodarzi, Samereh; Pazirandeh, Ali; Jameie, Seyed Behnamedin; Baghban Khojasteh, Nasrin

    2012-01-01

    Boron distribution in adult male and female rats' normal brain after boron carrier injection (0.005 g Boric Acid+0.005 g Borax+10 ml distilled water, pH: 7.4) was studied in this research. Coronal sections of control and trial animal tissue samples were irradiated with thermal neutrons. Using alpha autoradiography, significant differences in boron concentration were seen in forebrain, midbrain and hindbrain sections of male and female animal groups with the highest value, four hours after boron compound injection. - Highlights: ► Boron distribution in male and female rats' normal brain was studied in this research. ► Coronal sections of animal tissue samples were irradiated with thermal neutrons. ► Alpha and Lithium tracks were counted using alpha autoradiography. ► Different boron concentration was seen in brain sections of male and female rats. ► The highest boron concentration was seen in 4 h after boron compound injection.

  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 stress response and accumulation potential of the extremely tolerant species Puccinellia frigida.

    Science.gov (United States)

    Rámila, Consuelo D P; Contreras, Samuel A; Di Domenico, Camila; Molina-Montenegro, Marco A; Vega, Andrea; Handford, Michael; Bonilla, Carlos A; Pizarro, Gonzalo E

    2016-11-05

    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 (500mg/L), and within its tissues (>5000mg/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. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Absolute analysis of uranium isotopic concentrations with a gas ion source mass spectrometer; Analyses absolues des concentrations isotopiques de l'uranium par spectrometre de masse equipe d'une source a gaz

    Energy Technology Data Exchange (ETDEWEB)

    Chaussy, L.; Boyer, R. [Commissariat a l' Energie Atomique, Pierrelatte (France)

    1969-07-01

    Mass spectrometer with electronic bombardment ions source for routine uranium isotopic analysis are used like relative measurements apparatus. We show that such mass spectrometers can be used for absolute measurements with a very high sensitivity and precision which are ten times better than theses of thermo-ionic ions source mass spectrometer. We examine the causes of systematic errors and we give experimental data. In particular natural uranium sample used as reference give: U{sub 5} = 0.7202 {+-} 0.0005 atoms per cent; U{sub 4} = 0.00552 {+-} 0.0003 atoms per cent. The use of this method is justified for standards control. (authors) [French] Les spectrometres de masse a source par bombardement electronique pour l'analyse de l'uranium sous forme d'hexafluorure, sont utilises en routine comme des appareils de mesure relative. On montre que l'on peut utiliser de tels appareils pour effectuer des mesures absolues avec une excellente sensibilite et reproductibilite, dix fois superieure a celle des spectrometres a source thermoionique. On examine en detail les causes d'erreurs systematiques et on donne des resultats experimentaux. En particulier, l'analyse d'un echantillon d'uranium naturel donne: U{sub 5} = 0.7202 {+-} 0.0005 atomes pour cent; U{sub 4} = 0.00552 {+-} 0.0003 atomes pour cent. La technique de mesure est utile pour le controle d'etalons isotopiques. (auteurs)

  4. NGS Absolute Gravity Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NGS Absolute Gravity data (78 stations) was received in July 1993. Principal gravity parameters include Gravity Value, Uncertainty, and Vertical Gradient. The...

  5. Approach To Absolute Zero

    Indian Academy of Sciences (India)

    more and more difficult to remove heat as one approaches absolute zero. This is the ... A new and active branch of engineering ... This temperature is called the critical temperature, Te' For sulfur dioxide the critical ..... adsorbent charcoal.

  6. Roles of ATR1 paralogs YMR279c and YOR378w in boron stress tolerance

    International Nuclear Information System (INIS)

    Bozdag, Gonensin Ozan; Uluisik, Irem; Gulculer, Gulce Sila; Karakaya, Huseyin C.; Koc, Ahmet

    2011-01-01

    Highlights: → ATR1 paralog YMR279c plays role in boron detoxification. → YMR279c overexpression lowers cytoplasmic boron levels. → ATR1 paralog YOR378w has no roles in boron stress response. -- Abstract: Boron is a necessary nutrient for plants and animals, however excess of it causes toxicity. Previously, Atr1 and Arabidopsis Bor1 homolog were identified as the boron efflux pump in yeast, which lower the cytosolic boron concentration and help cells to survive in the presence of toxic amount of boron. In this study, we analyzed ATR1 paralogs, YMR279c and YOR378w, to understand whether they participate in boron stress tolerance in yeast. Even though these genes share homology with ATR1, neither their deletion rendered cells boron sensitive nor their expression was significantly upregulated by boron treatment. However, expression of YMR279, but not YOR378w, from the constitutive GAPDH promoter on a high copy plasmid provided remarkable boron resistance by decreasing intracellular boron levels. Thus our results suggest the presence of a third boron exporter, YMR279c, which functions similar to ATR1 and provides boron resistance in yeast.

  7. 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.)

  8. 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.

  9. 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

  10. Encasing the Absolutes

    Directory of Open Access Journals (Sweden)

    Uroš Martinčič

    2014-05-01

    Full Text Available The paper explores the issue of structure and case in English absolute constructions, whose subjects are deduced by several descriptive grammars as being in the nominative case due to its supposed neutrality in terms of register. This deduction is countered by systematic accounts presented within the framework of the Minimalist Program which relate the case of absolute constructions to specific grammatical factors. Each proposal is shown as an attempt of analysing absolute constructions as basic predication structures, either full clauses or small clauses. I argue in favour of the small clause approach due to its minimal reliance on transformations and unique stipulations. Furthermore, I propose that small clauses project a singular category, and show that the use of two cases in English absolute constructions can be accounted for if they are analysed as depictive phrases, possibly selected by prepositions. The case of the subject in absolutes is shown to be a result of syntactic and non-syntactic factors. I thus argue in accordance with Minimalist goals that syntactic case does not exist, attributing its role in absolutes to other mechanisms.

  11. 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...

  12. 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.

  13. Boron biodistribution in Beagles after intravenous infusion of 4-dihydroxyborylphenylalanine-fructose complex

    International Nuclear Information System (INIS)

    Kulvik, M.E.; Vaehaetalo, J.K.; Benczik, J.; Snellman, M.; Laakso, J.; Hermans, R.; Jaerviluoma, E.; Rasilainen, M.; Faerkkilae, M.; Kallio, M.E.

    2004-01-01

    Boron biodistribution after intravenous infusion of 4-dihydroxyborylphenylalanine-fructose (BPA-F) complex was investigated in six dogs. Blood samples were evaluated during and following doses of 205 and 250 mg/kgbw BPA in a 30 min infusion, and 500 mg/kgbw in a 1 h infusion. Samples from whole blood, urine, brain and other organs were analysed for boron content after varying times following the onset of infusion. The whole blood boron concentrations declined from 27 to 8.4 ppm over the period of 39-165 min after the onset of infusion and the levels increased from 1.9 to 12 ppm in the grey matter of the brain over the same period. The boron concentrations in whole blood decreased steadily, whereas the boron values in brain tissue rose steadily with time. It was concluded that whole blood boron concentrations do not seem to reflect accurately the boron concentration in brain tissue at respective time points

  14. The corrosion resistance of zinc coatings in the presence of boron-doped detonation nanodiamonds (DND)

    Science.gov (United States)

    Burkat, G. K.; Alexandrova, G. S.; Dolmatov, V. Yu; Osmanova, E. D.; Myllymäki, V.; Vehanen, A.

    2017-02-01

    The effect of detonation nanodiamonds, doped with boron (boron-DND) in detonation synthesis on the process of zinc electrochemical deposition from zincate electrolyte is investigated. It is shown that the scattering power (coating uniformity) increases 2-4 times (depending on the concentration of DND-boron electrolyte conductivity does not change, the corrosion resistance of Zn- DND -boron coating increases 2.6 times in 3% NaCl solution (corrosion currents) and 3 times in the climatic chamber.

  15. Design of a {gamma}-ray analysis system for determination of boron in a patient`s head, during neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Verbakel, W.F.A.R.

    1997-12-01

    Boron Neutron Capture Therapy (BNCT) is a new radiation therapy in which thermal neutron capture by {sup 10}B is used for the selective destruction of a cancer tumour. At the High Flux Reactor (HFR) in Petten, Netherlands, a therapy facility is built for the neutron irradiations. In first instance, patients with a brain tumour will be treated. The doses delivered to the tumour and to the healthy tissue depend on the thermal neutron fluence and on the boron concentrations in these regions. Yet, both concentrations change in time after the administration of the tumour-seeking boron compound. An accurate determination of the patient`s dose requires the knowledge of these time dependent concentrations during the therapy. For this reason, a {gamma}-ray telescope system, together with a reconstruction tool, are developed. Two HPGe-detectors measure the 478 keV prompt {gamma}-rays which are emitted at the boron neutron capture reaction, in a large background of {gamma}-rays and neutrons. By using the detectors in a telescope configuration, only {gamma}-rays emitted by a small specific region are detected. The best shielding of the detectors is obtained by performing the measurements through a small hole in the iron roof. A reconstruction tool is developed to calculate absolute boron concentrations using the measured boron {gamma}-ray detection rates. Besides the boron {gamma}-rays, a large component of 2.2 MeV {gamma}-rays emitted at thermal neutron capture in hydrogen is measured. Since the hydrogen distribution is almost homogeneous over the head, this component can serve as a measure of the total number of thermal neutrons in the observed volume. By using the hydrogen {gamma}-line for normalisation of the boron concentration, the reconstruction tool eliminates the greater part of the influence of the inhomogeneity of the thermal neutron distribution. MCNP calculations are used as a tool for the optimisation of the detector configuration. Experiments on a head phantom

  16. 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.

  17. 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

  18. 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)

  19. 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.

  20. Boron content of South African surface waters: prelimenary assessment for irrigation

    International Nuclear Information System (INIS)

    Reid, P.C.; Davies, E.

    1989-01-01

    Boron, a naturally occuring constituent of surface and ground water, is an essential plant nutrient. However, at relatively low concentrations, boron becomes toxic to plant growth. In order to assess the boron status in South African surface waters, the Department of Water Affairs launched a long-term boron water quality assessment programme in 1985, encompassing the analysis of water samples taken at 91 sites throughout South Africa. Results to date indicate that the boron concentration in South African surface waters varies between 0,02 to 0,33 mg l -1 . At these concentrations even the most boron sensitive crops can be grown without fear of boron toxicity. 3 refs., 1 fig., 2 tabs

  1. 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.

  2. 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

  3. Boron-containing thioureas for neutron capture therapy. Borhaltige Thioharnstoffe fuer die Neutroneneinfangtherapie

    Energy Technology Data Exchange (ETDEWEB)

    Ketz, H.

    1993-10-21

    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 [sup 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 [sup 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.)

  4. 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

  5. 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.

  6. Calibration with Absolute Shrinkage

    DEFF Research Database (Denmark)

    Øjelund, Henrik; Madsen, Henrik; Thyregod, Poul

    2001-01-01

    In this paper, penalized regression using the L-1 norm on the estimated parameters is proposed for chemometric je calibration. The algorithm is of the lasso type, introduced by Tibshirani in 1996 as a linear regression method with bound on the absolute length of the parameters, but a modification...

  7. Approach to Absolute Zero

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 2; Issue 10. Approach to Absolute Zero Below 10 milli-Kelvin. R Srinivasan. Series Article Volume 2 Issue 10 October 1997 pp 8-16. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/002/10/0008-0016 ...

  8. Measurement of absolute concentrations of minor reactive species in flames by cavity ring down absorption spectroscopy (CRDS) method; Mesure de concentrations absolues d'especes reactives minoritaires dans les flammes par la technique d'absorption cavity ring down spectroscopy (CRDS)

    Energy Technology Data Exchange (ETDEWEB)

    Mercier, X.

    2000-11-15

    Combustion processes, which represent our main source of energy today, arouse still numerous questioning. It likes essentially the complexity of the involved chemical mechanisms as well as in the inherent difficulty to the study of an environment which is the field of several thousand simultaneous reactions. Now, even if powerful models exist, allowing the simulation of complex chemical systems, they can not predict any process of combustion and the experimental approach of these ones is still essential for the improvement of the existing models. In particular, the quantitative measure of minor species in flames constitutes a fundamental stage in the validation of the chemical mechanisms with high temperature. It is in this optics that we developed a new technique for flames study, the Cavity Ring-Down Spectroscopy (CRDS). This technique (appeared to the end of the 80's (O' Keefe and Deacon [1988]) within the framework of a spectroscopic study) is similar to a very high sensibility absorption method. The principle of the CRDS technique is based on the measure of the lifetime of an laser pulse injected in an optical cavity within which is an absorbing sample. in this report, we show the interest and the potentialities of the CRDS for the study of homogeneous flames. To do it, we clarify in detail the principle of the CRDS and the care to be taken for the measure of absolute concentrations. Besides, a comparison of the absolute concentrations profiles obtained by CRDS (of CN and CH notably) in a CH{sub 4} /O{sub 2} flame seeded with NO, with those stemming from the modelling by means of the software PREMIX is also presented. The very good agreement which reveals this comparison tends to show that the CRDS, because of its high sensibility and its direct quantitative character, is one of the most efficient methods for the measure of minor species absolute concentrations in homogeneous flames. (author)

  9. Selective uptake of p-boronophenylalanine by osteosarcoma cells for boron neutron capture therapy

    Energy Technology Data Exchange (ETDEWEB)

    Ferrari, C. [Department of Surgery, Experimental Surgery Laboratory, University of Pavia, Piazza Botta, Pavia (Italy)], E-mail: ferraric@unipv.it; Zonta, C.; Cansolino, L.; Clerici, A.M.; Gaspari, A. [Department of Surgery, Experimental Surgery Laboratory, University of Pavia, Piazza Botta, Pavia (Italy); Altieri, S.; Bortolussi, S.; Stella, S. [Department of Nuclear and Theoretical Physics of University, Via Bassi, 6, Pavia (Italy); National Institute of Nuclear Physics (INFN) Section of Pavia, Via Bassi, 6, Pavia (Italy); Bruschi, P. [Department of Nuclear and Theoretical Physics of University, Via Bassi, 6, Pavia (Italy); Dionigi, P.; Zonta, A. [Department of Surgery, Experimental Surgery Laboratory, University of Pavia, Piazza Botta, Pavia (Italy)

    2009-07-15

    Osteosarcoma is the most common non-hematologic primary cancer type that develops in bone. Current osteosarcoma treatments combine multiagent chemotherapy with extensive surgical resection, which in some cases makes necessary the amputation of the entire limb. Nevertheless its infiltrative growth leads to a high incidence of local and distant recurrences that reduce the percentage of cured patients to less than 60%. These poor data required to set up a new therapeutic approach aimed to restrict the surgical removal meanwhile performing a radical treatment. Boron neutron capture therapy (BNCT), a particular radiotherapy based on the nuclear capture and fission reactions by atoms of {sup 10}B, when irradiated with thermal neutrons, could be a valid alternative or integrative option in case of osteosarcoma management, thanks to its peculiarity in selectively destroying neoplastic cells without damaging normal tissues. Aim of the present work is to investigate the feasibility of employing BNCT to treat the limb osteosarcoma. Boronophenylalanine (BPA) is used to carry {sup 10}B inside the neoplastic cells. As a first step the endocellular BPA uptake is tested in vitro on the UMR-106 osteosarcoma cell line. The results show an adequate accumulation capability. For the in vivo experiments, an animal tumor model is developed in Sprague-Dawley rats by means of an intrafemoral injection of UMR-106 cells at the condyle site. The absolute amounts of boron loading and the tumor to normal tissue {sup 10}B ratio are evaluated 2 h after the i.v. administration of BPA. The boron uptake by the neoplastic tissue is almost twice the normal one. However, higher values of boron concentration in tumor are requested before upholding BNCT as a valid therapeutic option in the treatment of osteosarcoma.

  10. 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

  11. 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)

  12. 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

  13. 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.

  14. Mathematical modeling based evaluation and simulation of boron removal in bioelectrochemical systems

    Energy Technology Data Exchange (ETDEWEB)

    Ping, Qingyun [Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 (United States); Abu-Reesh, Ibrahim M. [Department of Chemical Engineering, College of Engineering, Qatar University, P.O. Box 2713, Doha (Qatar); He, Zhen, E-mail: zhenhe@vt.edu [Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 (United States)

    2016-11-01

    Boron removal is an arising issue in desalination plants due to boron's toxicity. As an emerging treatment concept, bioelectrochemical systems (BES) can achieve potentially cost-effective boron removal by taking advantage of cathodic-produced alkali. Prior studies have demonstrated successful removal of boron in microbial desalination cells (MDCs) and microbial fuel cells (MFCs), both of which are representative BES. Herein, mathematical models were developed to further evaluate boron removal by different BES and understand the key operating factors. The models delivered very good prediction of the boron concentration in the MDC integrated with Donnan Dialysis (DD) system with the lowest relative root-mean-square error (RMSE) of 0.00%; the predication of the MFC performance generated the highest RMSE of 18.55%. The model results of salt concentration, solution pH, and current generation were well fitted with experimental data for RMSE values mostly below 10%. The long term simulation of the MDC-DD system suggests that the accumulation of salt in the catholyte/stripping solution could have a positive impact on the removal of boron due to osmosis-driven convection. The current generation in the MDC may have little influence on the boron removal, while in the MFC the current-driven electromigration can contribute up to 40% of boron removal. Osmosis-induced convection transport of boron could be the major driving force for boron removal to a low level < 2 mg L{sup −} {sup 1}. The ratio between the anolyte and the catholyte flow rates should be kept > 22.2 in order to avoid boron accumulation in the anolyte effluent. - Highlights: • Mathematical models are developed to understand boron removal in BES. • Boron removal can be driven by electromigration induced by current generation. • Diffusion induced by a salt concentration gradient also contributes to boron removal. • Osmosis and current driven convection transport play diverse roles in different BES.

  15. A global algorithm for estimating Absolute Salinity

    Science.gov (United States)

    McDougall, T. J.; Jackett, D. R.; Millero, F. J.; Pawlowicz, R.; Barker, P. M.

    2012-12-01

    The International Thermodynamic Equation of Seawater - 2010 has defined the thermodynamic properties of seawater in terms of a new salinity variable, Absolute Salinity, which takes into account the spatial variation of the composition of seawater. Absolute Salinity more accurately reflects the effects of the dissolved material in seawater on the thermodynamic properties (particularly density) than does Practical Salinity. When a seawater sample has standard composition (i.e. the ratios of the constituents of sea salt are the same as those of surface water of the North Atlantic), Practical Salinity can be used to accurately evaluate the thermodynamic properties of seawater. When seawater is not of standard composition, Practical Salinity alone is not sufficient and the Absolute Salinity Anomaly needs to be estimated; this anomaly is as large as 0.025 g kg-1 in the northernmost North Pacific. Here we provide an algorithm for estimating Absolute Salinity Anomaly for any location (x, y, p) in the world ocean. To develop this algorithm, we used the Absolute Salinity Anomaly that is found by comparing the density calculated from Practical Salinity to the density measured in the laboratory. These estimates of Absolute Salinity Anomaly however are limited to the number of available observations (namely 811). In order to provide a practical method that can be used at any location in the world ocean, we take advantage of approximate relationships between Absolute Salinity Anomaly and silicate concentrations (which are available globally).

  16. 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)

  17. 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

  18. Effekten af absolut kumulation

    DEFF Research Database (Denmark)

    Kyvsgaard, Britta; Klement, Christian

    2012-01-01

    Som led i finansloven for 2011 blev regeringen og forligspartierne enige om at undersøge reglerne om strafudmåling ved samtidig pådømmelse af flere kriminelle forhold og i forbindelse hermed vurdere konsekvenserne af at ændre de gældende regler i forhold til kapacitetsbehovet i Kriminalforsorgens...... samlet bødesum ved en absolut kumulation i forhold til en modereret kumulation, som nu er gældende....

  19. Preparation and characteristics of epoxy/clay/B4C nanocomposite at high concentration of boron carbide for neutron shielding application

    Science.gov (United States)

    Kiani, Mohammad Amin; Ahmadi, Seyed Javad; Outokesh, Mohammad; Adeli, Ruhollah; Mohammadi, Aghil

    2017-12-01

    In this research, the characteristics of the prepared samples in epoxy matrix by means of X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), as well as scanning electron microscope (SEM) are evaluated. Meanwhile, the obtained mechanical properties of the specimen are investigated. Thermogravimetric analysis (TGA) is also employed to evaluate the thermal degradation of manufactured nanocomposites. The thermal neutron absorption properties of nanocomposites containing 3 wt% of montmorillonite nanoclay (closite30B) have been studied experimentally, using an Am-Be point source. Mechanical tests reveal that the higher B4C concentrations, the more tensile strengths, but lower Young's modulus in all samples under consideration. TGA analysis also shows that thermal stability of the nanocomposite, increases in presence of B4C. Finally, neutron absorption analysis shows that increasing the B4C concentration leads to a nonlinearly build-up of neutron absorption cross section.

  20. Last Glacial to Holocene changes of deep and intermediate water carbonate ion concentrations in the Southern Ocean: constraints from foraminiferal Boron/Calcium ratios

    OpenAIRE

    Kersten, Franziska

    2013-01-01

    In this thesis, the first records of intermediate and deep water carbonate ion concentrations in the South Pacific were generated in order to study carbon cycle dynamics throughout the past 30,000 years. Benthic foraminiferal B/Ca, an indicator of past seawater carbonate ion saturation is the main paleoceanographic proxy that was used in this study. Down-core proxy studies carried out within the scope of this thesis were used to address currently unresolved questions about the origin, mechani...

  1. 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.

  2. 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

  3. 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

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

    KAUST Repository

    Zeboudji, B.

    2013-04-01

    Boron removal in seawater desalination presents a particular challenge. In seawater reverse osmosis (SWRO) systems boron removal at low concentration (<0.5 mg/L) is usually achieved by a second pass using brackish water RO membranes. However, 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 solution was carried out by EC process using aluminum and iron electrodes. Several operating parameters on the removal efficiency such as initial pH, current density, initial boron ion concentration, feed concentration, gap between electrodes, and electrode material, were investigated. In the case of bipolar electrocoagulation (BEC), an optimum removal efficiency of 96% corresponding to a final boron concentration of 0.4 mg/L was achieved at a current density of 6 mA/cm2 and pH = 8 using aluminum electrodes. The concentration of NaCl was 2,500 mg/L and the gap between the electrodes of 0.5 cm. Furthermore, a comparison between monopolar electrocoagulation (MEC) and BEC using both aluminum and iron electrodes was carried out. Results showed that the BEC process has reduced the current density applied to obtain high level of boron removal in a short reaction time compared to MEC process. The high performance of the EC showed that the process could be used to reduce boron concentration to acceptable levels at low-cost and more environmentally friendly. © 2013 Copyright Taylor and Francis Group, LLC.

  5. Measurement of boron isotope ratios in groundwater studies

    International Nuclear Information System (INIS)

    Porteous, N.C.; Walsh, J.N.; Jarvis, K.E.

    1995-01-01

    Boron is present at low levels in groundwater and rainfall in the UK, ranging between 2 and 200 ng ml -1 . A sensitive technique has been developed using inductively coupled plasma mass spectrometry (ICP-MS) to measure boron isotope ratios at low concentrations with a precision (s r ) of between 0.1 and 0.2%. Samples were evaporated to increase elemental boron concentrations to 200 ng ml -1 and interfering matrix elements were removed by an adapted cation-exchange separation procedure. The validity of measuring boron isotopic ratios by ICP-MS at this concentration level is discussed in relation to the theoretical instrument precision attainable based on counting statistics. (author)

  6. Toward a clinical application of ex situ boron neutron capture therapy for lung tumors at the RA-3 reactor in Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Farías, R. O.; Trivillin, V. A.; Portu, A. M.; Schwint, A. E.; González, S. J., E-mail: srgonzal@cnea.gov.ar [Comisión Nacional de Energía Atómica (CNEA), San Martín 1650, Argentina and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires 1033 (Argentina); Garabalino, M. A.; Monti Hughes, A.; Pozzi, E. C. C.; Thorp, S. I.; Curotto, P.; Miller, M. E.; Santa Cruz, G. A.; Saint Martin, G. [Comisión Nacional de Energía Atómica (CNEA), San Martín 1650 (Argentina); Ferraris, S.; Santa María, J.; Rovati, O.; Lange, F. [CIDME, Universidad Maimónides, Buenos Aires 1405 (Argentina); Bortolussi, S. [Istituto Nazionale di Fisica Nucleare, Sezione di Pavia 27100 (Italy); Altieri, S. [Istituto Nazionale di Fisica Nucleare, Sezione di Pavia 27100, Italy and Dipartimento di Fisica, Università di Pavia, Pavia 27100 (Italy)

    2015-07-15

    Purpose: Many types of lung tumors have a very poor prognosis due to their spread in the whole organ volume. The fact that boron neutron capture therapy (BNCT) would allow for selective targeting of all the nodules regardless of their position, prompted a preclinical feasibility study of ex situ BNCT at the thermal neutron facility of RA-3 reactor in the province of Buenos Aires, Argentina. (L)-4p-dihydroxy-borylphenylalanine fructose complex (BPA-F) biodistribution studies in an adult sheep model and computational dosimetry for a human explanted lung were performed to evaluate the feasibility and the therapeutic potential of ex situ BNCT. Methods: Two kinds of boron biodistribution studies were carried out in the healthy sheep: a set of pharmacokinetic studies without lung excision, and a set that consisted of evaluation of boron concentration in the explanted and perfused lung. In order to assess the feasibility of the clinical application of ex situ BNCT at RA-3, a case of multiple lung metastases was analyzed. A detailed computational representation of the geometry of the lung was built based on a real collapsed human lung. Dosimetric calculations and dose limiting considerations were based on the experimental results from the adult sheep, and on the most suitable information published in the literature. In addition, a workable treatment plan was considered to assess the clinical application in a realistic scenario. Results: Concentration-time profiles for the normal sheep showed that the boron kinetics in blood, lung, and skin would adequately represent the boron behavior and absolute uptake expected in human tissues. Results strongly suggest that the distribution of the boron compound is spatially homogeneous in the lung. A constant lung-to-blood ratio of 1.3 ± 0.1 was observed from 80 min after the end of BPA-F infusion. The fact that this ratio remains constant during time would allow the blood boron concentration to be used as a surrogate and indirect

  7. Emitting recombination of BCl molecules with chlorine atoms, resulting from dissociation of boron trichloride molecules under action of pulse CO2-laser radiation

    International Nuclear Information System (INIS)

    Nikonorov, A.P.; Moskvitina, E.N.; Kuzyakov, Yu.Ya.; Stepanov, P.I.

    1983-01-01

    Luminescence in BCl 3 is investigated. The results of measurements of gas temperature, BCl molecules concentration, and luminescence absolute intensity at boron trichloride presure of 40 mm pH and density of laser pulse energy from 1.7 up to 4.0 J/cm 2 are obtained. Nature of uninterrupted spectrum is considered. It is established that luminescence appearing in the BCl 3 under action of pulse CO 2 -laser is caused by reaction of emitting recombination of BCl molecules with chlorine atoms. Rate constant of this reaction in the range of 2300-3100 K is determined

  8. Density functional theory investigation of oxygen interaction with boron-doped graphite

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Juan; Wang, Chen [State Key Lab of New Ceramic and Fine Processing, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China); Liang, Tongxiang, E-mail: txliang@tsinghua.edu.cn [State Key Lab of New Ceramic and Fine Processing, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China); Lai, Wensheng [Advanced Material Laboratory, School of Materials Science & Engineering, Tsinghua University, Beijing, 100084 (China)

    2016-12-30

    Highlights: • Density-functional approach is applied to study the interaction of oxygen with boron-doped graphite. • Adsorption and diffusion of oxygen atoms on boron doped graphite surfaces are studied. • Recombination of oxygen is investigated by ER and LH mechanisms. • Low boron concentration facilitates O{sub 2} formation while high boron loading inhibits the recombination. • The presence of B−B bonds due to boron accumulation makes it impossible for oxygen recombination. - Abstract: Boron inserted as impurity by substitution of carbon atoms in graphite is known to change (improve or deteriorate) oxidation resistance of nuclear graphite, but the reason for both catalytic and inhibiting oxidation is still uncertain. As a first step, this work is more specially devoted to the adsorption and diffusion of oxygen atoms on the surface and related to the problem of oxygen retention on the pure and boron-containing graphite surfaces. Adsorption energies and energy barriers associated to the diffusion for molecular oxygen recombination are calculated in the density functional theory framework. The existence of boron modifies the electronic structure of the surface, which results in an increase of the adsorption energy for O. However, low boron loading makes it easier for the recombination into molecular oxygen. For high boron concentration, it induces a better O retention capability in graphite because the presence of B-B bonds decreases recombination of the adsorbed oxygen atoms. A possible explanation for both catalytic and inhibiting effects of boron in graphite is proposed.

  9. Towards absolute neutrino masses

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, Petr [Kellogg Radiation Laboratory 106-38, Caltech, Pasadena, CA 91125 (United States)

    2007-06-15

    Various ways of determining the absolute neutrino masses are briefly reviewed and their sensitivities compared. The apparent tension between the announced but unconfirmed observation of the 0{nu}{beta}{beta} decay and the neutrino mass upper limit based on observational cosmology is used as an example of what could happen eventually. The possibility of a 'nonstandard' mechanism of the 0{nu}{beta}{beta} decay is stressed and the ways of deciding which of the possible mechanisms is actually operational are described. The importance of the 0{nu}{beta}{beta} nuclear matrix elements is discussed and their uncertainty estimated.

  10. 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...

  11. 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)

  12. 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.)

  13. 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

  14. 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

  15. 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.).

  16. 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.

  17. An empirical model for parameters affecting energy consumption in boron removal from boron-containing wastewaters 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)

    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 6.0mA/cm{sup 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{sup 6}x[OH]{sup 0.11}x[CD]{sup 0.62}x[IBC]{sup -0.57}x[DSE]{sup -0.}= {sup 04}x[T]{sup -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.

  18. Accuracy Improvement of Boron Meter Adopting New Fitting Function and Multi-Detector

    Directory of Open Access Journals (Sweden)

    Chidong Kong

    2016-12-01

    Full Text Available This paper introduces a boron meter with improved accuracy compared with other commercially available boron meters. Its design includes a new fitting function and a multi-detector. In pressurized water reactors (PWRs in Korea, many boron meters have been used to continuously monitor boron concentration in reactor coolant. However, it is difficult to use the boron meters in practice because the measurement uncertainty is high. For this reason, there has been a strong demand for improvement in their accuracy. In this work, a boron meter evaluation model was developed, and two approaches were considered to improve the boron meter accuracy: the first approach uses a new fitting function and the second approach uses a multi-detector. With the new fitting function, the boron concentration error was decreased from 3.30 ppm to 0.73 ppm. With the multi-detector, the count signals were contaminated with noise such as field measurement data, and analyses were repeated 1,000 times to obtain average and standard deviations of the boron concentration errors. Finally, using the new fitting formulation and multi-detector together, the average error was decreased from 5.95 ppm to 1.83 ppm and its standard deviation was decreased from 0.64 ppm to 0.26 ppm. This result represents a great improvement of the boron meter accuracy.

  19. Accuracy improvement of boron meter adopting new fitting function and multi-detector

    Energy Technology Data Exchange (ETDEWEB)

    Kong, Chidong; Lee, Hyun Suk; Tak, Tae Woo; Lee, Deok Jung [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of); KIm, Si Hwan; Lyou, Seok Jean [Users Incorporated Company, Hansin S-MECA, Daejeon (Korea, Republic of)

    2016-12-15

    This paper introduces a boron meter with improved accuracy compared with other commercially available boron meters. Its design includes a new fitting function and a multi-detector. In pressurized water reactors (PWRs) in Korea, many boron meters have been used to continuously monitor boron concentration in reactor coolant. However, it is difficult to use the boron meters in practice because the measurement uncertainty is high. For this reason, there has been a strong demand for improvement in their accuracy. In this work, a boron meter evaluation model was developed, and two approaches were considered to improve the boron meter accuracy: the first approach uses a new fitting function and the second approach uses a multi-detector. With the new fitting function, the boron concentration error was decreased from 3.30 ppm to 0.73 ppm. With the multi-detector, the count signals were contaminated with noise such as field measurement data, and analyses were repeated 1,000 times to obtain average and standard deviations of the boron concentration errors. Finally, using the new fitting formulation and multi-detector together, the average error was decreased from 5.95 ppm to 1.83 ppm and its standard deviation was decreased from 0.64 ppm to 0.26 ppm. This result represents a great improvement of the boron meter accuracy.

  20. Boron exposure assessment using drinking water and urine in the North of Chile

    Energy Technology Data Exchange (ETDEWEB)

    Cortes, S., E-mail: scortes@med.puc.cl [Departamento de Salud Publica, Pontificia Universidad Catolica de Chile, Santiago (Chile); Reynaga-Delgado, E. [Centro de Investigaciones Biologicas del Noroeste, La Paz B.C.S. (Mexico); Sancha, A.M. [Facultad de Ciencias Fisicas y Matematicas, Universidad de Chile, Santiago (Chile); Ferreccio, C. [Departamento de Salud Publica, Pontificia Universidad Catolica de Chile, Santiago (Chile)

    2011-12-01

    Boron is an essential trace element for plants and humans however it is still an open question what levels of boron are actually safe for humans. This study, conducted between 2006 and 2010, measured exposure levels of boron in drinking water and urine of volunteers in Arica, an area in the North of Chile with high levels of naturally occurring boron. Samples were taken of tap and bottled water (173 and 22, respectively), as well as urine from 22 volunteers, and subsequently analyzed by inductively coupled plasma spectroscopy (ICP-OES). Boron varied in public tap water from 0.22 to 11.3 mg L{sup -1}, with a median value of 2.9 mg L{sup -1}, while concentrations of boron in bottled water varied from 0.01 to 12.2 mg L{sup -1}. Neither tap nor bottled water samples had concentrations of boron within WHO recommended limits. The concentration of boron in urine varied between 0.45 and 17.4 mg L{sup -1}, with a median of 4.28 mg L{sup -1} and was found to be correlated with tap water sampled from the homes of the volunteers (r = 0.64). Authors highly recommend that in northern Chile - where levels of boron are naturally high - that the tap and bottled water supplies be monitored in order to protect public health and that regulatory standards also be established for boron in drinking water in order to limit exposure.

  1. Thermodynamics of negative absolute pressures

    International Nuclear Information System (INIS)

    Lukacs, B.; Martinas, K.

    1984-03-01

    The authors show that the possibility of negative absolute pressure can be incorporated into the axiomatic thermodynamics, analogously to the negative absolute temperature. There are examples for such systems (GUT, QCD) processing negative absolute pressure in such domains where it can be expected from thermodynamical considerations. (author)

  2. Spectrographic determination of traces of boron in steels

    International Nuclear Information System (INIS)

    Alduan, F.A.; Roca, M.

    1976-01-01

    A spectrographic method has been developed to determine quantitatively boron in steels in the 0.5 to 250 ppm concentration range. The samples are dissolved in acids and transformed into oxides, avoiding boron losses by the addition of mannitol. For the fluoride evolution of boron in the dc arc the following compounds have been considered: CuF 2 , LiF, NaF, and SrF 2 . CuF 2 , at a concentration of 10%, provides the highest line-to-background intensity ratio. An arc current of 5 amperes eliminates the interference from iron spectrum on the most sensitive boron line - B 2497.7 A. Variations in chromium and nickel contents have no effect on the analytical results. (author)

  3. Electrodialysis of boron-containing solutions using homogeneuos ionite membranes

    International Nuclear Information System (INIS)

    Pilipenko, A.T.; Grebenyuk, V.D.; Mel'nik, L.A.

    1989-01-01

    Electrodialysis of boron-containing solutions is studied when preparing potable water from the sea one with the limiting admissible concentration (LAC) of boron 0.5 mg/dm 3 . It is ascertained that at pH>7 diffusion permeability of anion- and cation-exchange membranes as regards boron reduces both in the absence of external field and at current density 0.3 A/dm 3 . It is shown that when MK-100 homogeneous cationic membranes and MA-100 homogeneous anionic membranes are used, boron concentration in dialyzate decreases to LAC, if the process is realized in acid and low-acid media and if the depth of freshening increases to 0.2g/l

  4. 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.

  5. Absolute Gravimetry in Fennoscandia

    DEFF Research Database (Denmark)

    Pettersen, B. R; TImmen, L.; Gitlein, O.

    The Fennoscandian postglacial uplift has been mapped geometrically using precise levelling, tide gauges, and networks of permanent GPS stations. The results identify major uplift rates at sites located around the northern part of the Gulf of Bothnia. The vertical motions decay in all directions...... motions) has its major axis in the direction of southwest to northeast and covers a distance of about 2000 km. Absolute gravimetry was made in Finland and Norway in 1976 with a rise-and fall instrument. A decade later the number of gravity stations was expanded by JILAg-5, in Finland from 1988, in Norway...... time series of several years are now available. Along the coast there are nearby tide gauge stations, many of which have time series of several decades. We describe the observing network, procedures, auxiliary observations, and discuss results obtained for selected sites. We compare the gravity results...

  6. The major facilitator superfamily transporter Knq1p modulates boron homeostasis in Kluyveromyces lactis.

    Science.gov (United States)

    Svrbicka, Alexandra; Toth Hervay, Nora; Gbelska, Yvetta

    2016-03-01

    Boron is an essential micronutrient for living cells, yet its excess causes toxicity. To date, the mechanisms of boron toxicity are poorly understood. Recently, the ScATR1 gene has been identified encoding the main boron efflux pump in Saccharomyces cerevisiae. In this study, we analyzed the ScATR1 ortholog in Kluyveromyces lactis--the KNQ1 gene, to understand whether it participates in boron stress tolerance. We found that the KNQ1 gene, encoding a permease belonging to the major facilitator superfamily, is required for K. lactis boron tolerance. Deletion of the KNQ1 gene led to boron sensitivity and its overexpression increased K. lactis boron tolerance. The KNQ1 expression was induced by boron and the intracellular boron concentration was controlled by Knq1p. The KNQ1 promoter contains two putative binding motifs for the AP-1-like transcription factor KlYap1p playing a central role in oxidative stress defense. Our results indicate that the induction of the KNQ1 expression requires the presence of KlYap1p and that Knq1p like its ortholog ScAtr1p in S. cerevisiae functions as a boron efflux pump providing boron resistance in K. lactis.

  7. 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.

  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. Boron enhances strength and alters mineral composition of bone in rabbits fed a high energy diet.

    Science.gov (United States)

    Hakki, Sema S; Dundar, Niyazi; Kayis, Seyit Ali; Hakki, Erdogan E; Hamurcu, Mehmet; Kerimoglu, Ulku; Baspinar, Nuri; Basoglu, Abdullah; Nielsen, Forrest H

    2013-04-01

    An experiment was performed to determine whether boron had a beneficial effect on bone strength and composition in rabbits with apparent adiposity induced by a high energy diet. Sixty female New Zealand rabbits, aged 8 months, were randomly divided into five groups with the following treatments for seven months: control 1, fed alfalfa hay only (5.91 MJ/kg); control 2, high energy diet (11.76 MJ and 3.88 mg boron/kg); B10, high energy diet+10 mg/kg body weight boron gavage/96 h; B30, high energy diet+30 mg/kg body weight boron gavage/96 h; B50, high energy diet+50mg/kg body weight boron gavage/96 h. Bone boron concentrations were lowest in rabbits fed the high energy diet without boron supplementation, which suggested an inferior boron status. Femur maximum breaking force was highest in the B50 rabbits. Tibia compression strength was highest in B30 and B50 rabbits. All boron treatments significantly increased calcium and magnesium concentrations, and the B30 and B50 treatments increased the phosphorus concentration in tibia of rabbits fed the high energy diet. The B30 treatment significantly increased calcium, phosphorus and magnesium concentrations in femur of rabbits fed the high energy diet. Principal component analysis of the tibia minerals showed that the three boron treatments formed a separate cluster from controls. Discriminant analysis suggested that the concentrations of the minerals in femur could predict boron treatment. The findings indicate boron has beneficial effects on bone strength and mineral composition in rabbits fed a high energy diet. Copyright © 2012 Elsevier GmbH. All rights reserved.

  10. 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)

  11. 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)

  12. Proposed physiologic functions of boron in plants pertinent to animal and human metabolism.

    Science.gov (United States)

    Blevins, D G; Lukaszewski, K M

    1994-01-01

    Boron has been recognized since 1923 as an essential micronutrient element for higher plants. Over the years, many roles for boron in plants have been proposed, including functions in sugar transport, cell wall synthesis and lignification, cell wall structure, carbohydrate metabolism, RNA metabolism, respiration, indole acetic acid metabolism, phenol metabolism and membrane transport. However, the mechanism of boron involvement in each case remains unclear. Recent work has focused on two major plant-cell components: cell walls and membranes. In both, boron could play a structural role by bridging hydroxyl groups. In membranes, it could also be involved in ion transport and redox reactions by stimulating enzymes like nicotinamide adenine dinucleotide and reduced (NADH) oxidase. There is a very narrow window between the levels of boron required by and toxic to plants. The mechanisms of boron toxicity are also unknown. In nitrogen-fixing leguminous plants, foliarly applied boron causes up to a 1000% increase in the concentration of allantoic acid in leaves. In vitro studies show that boron inhibits the manganese-dependent allantoate amidohydrolase, and foliar application of manganese prior to application of boron eliminates allantoic acid accumulation in leaves. Interaction between borate and divalent cations like manganese may alter metabolic pathways, which could explain why higher concentrations of boron can be toxic to plants. PMID:7889877

  13. Combined Effects of Boron and NaCl on Wheat Seedlings

    Directory of Open Access Journals (Sweden)

    ZHEN Mei-nan

    2015-08-01

    Full Text Available To investigate the combined effects of boron(Band NaCl on the growth of wheat, a pot experiment was conducted using wheat (Triticum aestivum Linn.seedlings. Boron concentrations of culture medium were set as 0, 50 mg·kg-1 and 100 mg·kg-1, and NaCl concentrations were 0, 1 g·kg-1 and 2 g·kg-1. The results showed that both boron and NaCl could significantly inhibit wheat growth. At 50 mg B·kg-1, NaCl aggravated growth inhibition caused by boron. At 100 mg B·kg-1, however, NaCl alleviated the inhibition caused by boron. The combined stress of boron and NaCl significantly increased the root to shoot ratio of wheat. NaCl inhibited the uptake of boron by wheat. It suggests that under severe boron stress, NaCl is able to alleviate boron toxicity in wheat by increasing root to shoot ratio and reducing boron uptake.

  14. Rapid transporter regulation prevents substrate flow traffic jams in boron transport

    Science.gov (United States)

    Sotta, Naoyuki; Duncan, Susan; Tanaka, Mayuki; Sato, Takafumi

    2017-01-01

    Nutrient uptake by roots often involves substrate-dependent regulated nutrient transporters. For robust uptake, the system requires a regulatory circuit within cells and a collective, coordinated behaviour across the tissue. A paradigm for such systems is boron uptake, known for its directional transport and homeostasis, as boron is essential for plant growth but toxic at high concentrations. In Arabidopsis thaliana, boron uptake occurs via diffusion facilitators (NIPs) and exporters (BORs), each presenting distinct polarity. Intriguingly, although boron soil concentrations are homogenous and stable, both transporters manifest strikingly swift boron-dependent regulation. Through mathematical modelling, we demonstrate that slower regulation of these transporters leads to physiologically detrimental oscillatory behaviour. Cells become periodically exposed to potentially cytotoxic boron levels, and nutrient throughput to the xylem becomes hampered. We conclude that, while maintaining homeostasis, swift transporter regulation within a polarised tissue context is critical to prevent intrinsic traffic-jam like behaviour of nutrient flow. PMID:28870285

  15. A global algorithm for estimating Absolute Salinity

    Directory of Open Access Journals (Sweden)

    T. J. McDougall

    2012-12-01

    Full Text Available The International Thermodynamic Equation of Seawater – 2010 has defined the thermodynamic properties of seawater in terms of a new salinity variable, Absolute Salinity, which takes into account the spatial variation of the composition of seawater. Absolute Salinity more accurately reflects the effects of the dissolved material in seawater on the thermodynamic properties (particularly density than does Practical Salinity.

    When a seawater sample has standard composition (i.e. the ratios of the constituents of sea salt are the same as those of surface water of the North Atlantic, Practical Salinity can be used to accurately evaluate the thermodynamic properties of seawater. When seawater is not of standard composition, Practical Salinity alone is not sufficient and the Absolute Salinity Anomaly needs to be estimated; this anomaly is as large as 0.025 g kg−1 in the northernmost North Pacific. Here we provide an algorithm for estimating Absolute Salinity Anomaly for any location (x, y, p in the world ocean.

    To develop this algorithm, we used the Absolute Salinity Anomaly that is found by comparing the density calculated from Practical Salinity to the density measured in the laboratory. These estimates of Absolute Salinity Anomaly however are limited to the number of available observations (namely 811. In order to provide a practical method that can be used at any location in the world ocean, we take advantage of approximate relationships between Absolute Salinity Anomaly and silicate concentrations (which are available globally.

  16. Determination of boron in natural waters using atomic-absorption spectrometry with electrothermal atomization

    International Nuclear Information System (INIS)

    Usenko, S.I.; Prorok, M.M.

    1992-01-01

    A method of direct determination of boron in natural waters using atomic-absorption spectrometry with electrothermal atomization was developed. Concomitant elements Si, K, Mg, Na, present in natural waters in the concentration of 0.05-100 mg/cv 3 , do not produce effect on the value of boron atomic absorption. Boron determination limit constituted 0.02 mg/cm 3 for 25 ml of solution introduced

  17. Microstructural characterization aluminium alloys from the addition of boron

    International Nuclear Information System (INIS)

    Nunes, A.G.P.; Pipano, T.F.; Mota, M.A.; Mariano, N.A.; Ramos, E.C.T.

    2014-01-01

    In the electrical industry, the aluminum becomes attractive because it has excellent characteristics for transmitting electricity. The liquid aluminum has in its composition transition elements (zirconium, titanium, vanadium and chromium) that interfere negatively on the quality of the product. The addition of aluminum-boron alloys have been used to remove transition metals through the formation of borides, enabling an increase in electrical conductivity. However, no detailed reports of reactions between boron, transition metals and primary aluminum engines. However, the objective is to determine the stoichiometric composition that enables an increase in electrical conductivity of an aluminum alloy. Samples with different concentrations of boron were characterized by optical emission spectrometry, electrical conductivity and X-ray diffraction. The addition of boron in excess reduces the time in the formation of borides, and enable an increase in electrical conductivity. (author)

  18. Interaction of boron with graphite: A van der Waals density functional study

    International Nuclear Information System (INIS)

    Liu, Juan; Wang, Chen; Liang, Tongxiang; Lai, Wensheng

    2016-01-01

    Highlights: • A van der Waals density-functional approach is applied to study the interaction of boron with graphite. • VdW-DF functionals give fair agreement of crystal parameters with experiments. • The π electron approaches boron while adsorbing on graphite surface. • The hole introduced by boron mainly concentrates on boron and the nearest three carbon atoms. • PBE cannot describe the interstitial boron in graphite because of the ignoring binding of graphite sheets. - Abstract: Boron doping has been widely investigated to improve oxidation resistance of graphite. In this work the interaction of boron with graphite is investigated by a van der Waals density-functional approach (vdW-DF). The traditional density-functional theory (DFT) is well accounted for the binding in boron-substituted graphite. However, to investigate the boron atom on graphite surface and the interstitial impurities require use of a description of graphite interlayer binding. Traditional DFT cannot describe the vdW physics, for instance, GGA calculations show no relevant binding between graphite sheets. LDA shows some binding, but they fail to provide an accurate account of vdW forces. In this paper, we compare the calculation results of graphite lattice constant and cohesive energy by several functionals, it shows that vdW-DF such as two optimized functionals optB88-vdW and optB86b-vdW give much improved results than traditional DFT. The vdW-DF approach is then applied to study the interaction of boron with graphite. Boron adsorption, substitution, and intercalation are discussed in terms of structural parameters and electronic structures. When adsorbing on graphite surface, boron behaves as π electron acceptor. The π electron approaches boron atom because of more electropositive of boron than carbon. For substitution situation, the hole introduced by boron mainly concentrates on boron and the nearest three carbon atoms. The B-doped graphite system with the hole has less

  19. Interaction of boron with graphite: A van der Waals density functional study

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Juan; Wang, Chen [Beijing Key Lab of Fine Ceramics, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China); Liang, Tongxiang, E-mail: txliang@tsinghua.edu.cn [State Key Lab of New Ceramic and Fine Processing, Tsinghua University, Beijing 100084 (China); Lai, Wensheng [Advanced Material Laboratory, School of Materials Science & Engineering, Tsinghua University, Beijing, 100084 (China)

    2016-08-30

    Highlights: • A van der Waals density-functional approach is applied to study the interaction of boron with graphite. • VdW-DF functionals give fair agreement of crystal parameters with experiments. • The π electron approaches boron while adsorbing on graphite surface. • The hole introduced by boron mainly concentrates on boron and the nearest three carbon atoms. • PBE cannot describe the interstitial boron in graphite because of the ignoring binding of graphite sheets. - Abstract: Boron doping has been widely investigated to improve oxidation resistance of graphite. In this work the interaction of boron with graphite is investigated by a van der Waals density-functional approach (vdW-DF). The traditional density-functional theory (DFT) is well accounted for the binding in boron-substituted graphite. However, to investigate the boron atom on graphite surface and the interstitial impurities require use of a description of graphite interlayer binding. Traditional DFT cannot describe the vdW physics, for instance, GGA calculations show no relevant binding between graphite sheets. LDA shows some binding, but they fail to provide an accurate account of vdW forces. In this paper, we compare the calculation results of graphite lattice constant and cohesive energy by several functionals, it shows that vdW-DF such as two optimized functionals optB88-vdW and optB86b-vdW give much improved results than traditional DFT. The vdW-DF approach is then applied to study the interaction of boron with graphite. Boron adsorption, substitution, and intercalation are discussed in terms of structural parameters and electronic structures. When adsorbing on graphite surface, boron behaves as π electron acceptor. The π electron approaches boron atom because of more electropositive of boron than carbon. For substitution situation, the hole introduced by boron mainly concentrates on boron and the nearest three carbon atoms. The B-doped graphite system with the hole has less

  20. Boron biodistribution study in colorectal liver metastases patients in Argentina

    International Nuclear Information System (INIS)

    Cardoso, J.; Nievas, S.; Pereira, M.; Schwint, A.; Trivillin, V.; Pozzi, E.; Heber, E.; Monti Hughes, A.; Sanchez, P.; Bumaschny, E.; Itoiz, M.; Liberman, S.

    2009-01-01

    Ex-situ BNCT for multifocal unresectable liver metastases employing whole or partial autograft techniques requires knowledge of boron concentrations in healthy liver and metastases following perfusion and immersion in Wisconsin solution (W), the procedure employed for organ preservation during ex-situ irradiation. Measurements of boron concentration in blood, liver and metastases following an intravenous infusion of BPA-F in five colorectal liver metastases patients scheduled for surgery were performed. Tissue samples were evaluated for boron content pre and post perfusion and immersion in W. Complementary histological studies were performed. The data showed a dose-dependent BPA uptake in liver, a boron concentration ratio liver/blood close to 1 and a wide spread in the metastases/liver concentration ratios in the range 0.8-3.6, partially attributable to histological variations between samples. Based on the boron concentrations and dose considerations (liver≤ 15 Gy-Eq and tumor≥40 Gy-Eq) at the RA-3 thermal neutron facility (mean flux of about (6±1)x10 9 n cm -2 s -1 ), ex-situ treatment of liver metastases at RA-3 would be feasible.

  1. Study of the effects of focused high-energy boron ion implantation in diamond

    Science.gov (United States)

    Ynsa, M. D.; Agulló-Rueda, F.; Gordillo, N.; Maira, A.; Moreno-Cerrada, D.; Ramos, M. A.

    2017-08-01

    Boron-doped diamond is a material with a great technological and industrial interest because of its exceptional chemical, physical and structural properties. At modest boron concentrations, insulating diamond becomes a p-type semiconductor and at higher concentrations a superconducting metal at low temperature. The most conventional preparation method used so far, has been the homogeneous incorporation of boron doping during the diamond synthesis carried out either with high-pressure sintering of crystals or by chemical vapour deposition (CVD) of films. With these methods, high boron concentration can be included without distorting significantly the diamond crystalline lattice. However, it is complicated to manufacture boron-doped microstructures. A promising alternative to produce such microstructures could be the implantation of focused high-energy boron ions, although boron fluences are limited by the damage produced in diamond. In this work, the effect of focused high-energy boron ion implantation in single crystals of diamond is studied under different irradiation fluences and conditions. Micro-Raman spectra of the sample were measured before and after annealing at 1000 °C as a function of irradiation fluence, for both superficial and buried boron implantation, to assess the changes in the diamond lattice by the creation of vacancies and defects and their degree of recovery after annealing.

  2. 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)

  3. Absolute risk, absolute risk reduction and relative risk

    Directory of Open Access Journals (Sweden)

    Jose Andres Calvache

    2012-12-01

    Full Text Available This article illustrates the epidemiological concepts of absolute risk, absolute risk reduction and relative risk through a clinical example. In addition, it emphasizes the usefulness of these concepts in clinical practice, clinical research and health decision-making process.

  4. 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

  5. Tumor cell killing effect of boronated dipeptide. Boromethylglycylphenylalanine on boron neutron capture therapy for malignant brain tumors

    International Nuclear Information System (INIS)

    Takagaki, Masao; Ono, Koji; Masunaga, Shinichiro; Kinashi, Yuko; Kobayashi, Toru; Oda, Yoshifumi; Kikuchi, Haruhiko; Spielvogel, B.F.

    1994-01-01

    The killing effect of Boron Neutron Capture Therapy; BNCT, is dependant on the boron concentration ratio of tumor to normal brain (T/N ratio), and also that of tumor to blood (T/B ratio). The clinical boron carrier of boro-captate (BSH) showed the large T/N ratio of ca. 8, however the T/B ratio was around 1, which indicated nonselective accumulation into tumor. Indeed high boron concentration of blood restrict the neutron irradiation dose in order to circumvent the normal endothelial damage, especially in the case of deeply seated tumor. Phenylalanine analogue of para borono-phenylalanine (BPA) is an effective boron carrier on BNCT for malignant melanoma. For the BNCT on brain tumors, however, BPA concentration in normal brain was reported to be intolerably high. In order to improve the T/N ratio of BPA in brain, therefore, a dipeptide of boromethylglycylphenylalanine (BMGP) was synthesized deriving from trimethylglycine conjugated with BPA. It is expected to be selectively accumulated into tumor with little uptake into normal brain. Because a dipeptide might not pass through the normal blood brain barrier (BBB). Its killing effect on cultured glioma cell, T98G, and its distribution in rat brain bearing 9L glioma have been investigated in this paper. The BNCT effect of BMGP on cultured cells was nearly triple in comparison with DL-BPA. The neutron dose yielding 1% survival ratio were 7x10 12 nvt for BMGP and 2x10 13 nvt for BPA respectively on BNCT after boron loading for 16 hrs in the same B-10 concentration of 20ppm. Quantitative study of boron concentration via the α-auto radiography and the prompt gamma ray assay on 9L brain tumor rats revealed that T/N ratio and T/B ratio are 12.0 and 3.0 respectively. Those values are excellent for BNCT use. (author)

  6. 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.

  7. Projective absoluteness for Sacks forcing

    NARCIS (Netherlands)

    Ikegami, D.

    2009-01-01

    We show that Sigma(1)(3)-absoluteness for Sacks forcing is equivalent to the nonexistence of a Delta(1)(2) Bernstein set. We also show that Sacks forcing is the weakest forcing notion among all of the preorders that add a new real with respect to Sigma(1)(3) forcing absoluteness.

  8. 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.

  9. Oxytetracycline as a new analytical reagent for the spectrophotometric determination of boron

    Energy Technology Data Exchange (ETDEWEB)

    Narayana, G L

    1984-05-01

    Oxytetracycline hydrochloride, Terramycin, is introduced as a new reagent for the spectrophotometric determination of trace quantities of boron in concentrated sulphuric acid medium. The reagent has an absorption maximum at 430 nm, and that of the boron complex at 520 nm. The colored system conformed to Beer's law between 2 and 10 ..mu..g of boron at 520 nm. The molar absorptivity calculated on the basis of boron is 10,800 1 mol/sup -1/ cm/sup -1/. The composition of the complex has been shown to be 1:1 both by the slope ratio and molar ratio methods. 16 references.

  10. Oxytetracycline as a new analytical reagent for the spectrophotometric determination of boron

    International Nuclear Information System (INIS)

    Narayana, G.L.

    1984-01-01

    Oxytetracycline hydrochloride, Terramycin, is introduced as a new reagent for the spectrophotometric determination of trace quantities of boron in concentrated sulphuric acid medium. The reagent has an absorption maximum at 430 nm, and that of the boron complex at 520 nm. The coloured system conformed to Beer's law between 2 and 10 μg of boron at 520 nm. The molar absorptivity calculated on the basis of boron is 10,800 1 mol -1 cm -1 . The composition of the complex has been shown to be 1:1 both by the slope ratio and molar ratio methods. (author)

  11. Boronic ionogel electrolytes to improve lithium transport for Li-ion batteries

    International Nuclear Information System (INIS)

    Lee, Albert S.; Lee, Jin Hong; Hong, Soon Man; Lee, Jong-Chan; Hwang, Seung Sang; Koo, Chong Min

    2016-01-01

    Boron containing ionogels were fabricated through chemical crosslinking of boron allyloxide with polyethylene glycol dimethacrylate in an ionic liquid electrolyte solution to obtain mechanically robust gels. Because of the relatively small concentration of crosslinking agent required to fully solidify the ionic liquid electrolyte, good characters of high ionic conductivity, high thermal stability, and good electrochemical stability were observed. A spectroscopic investigation of the boronic ionogels revealed that the lithium mobility was noticeably enhanced compared with ionogels fabricated without the boronic crosslinker, leading to promising Li-ion battery performance at elevated temperatures.

  12. Comparative study of boron transport models in NRC Thermal-Hydraulic Code Trace

    Energy Technology Data Exchange (ETDEWEB)

    Olmo-Juan, Nicolás; Barrachina, Teresa; Miró, Rafael; Verdú, Gumersindo; Pereira, Claubia, E-mail: nioljua@iqn.upv.es, E-mail: tbarrachina@iqn.upv.es, E-mail: rmiro@iqn.upv.es, E-mail: gverdu@iqn.upv.es, E-mail: claubia@nuclear.ufmg.br [Institute for Industrial, Radiophysical and Environmental Safety (ISIRYM). Universitat Politècnica de València (Spain); Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear

    2017-07-01

    Recently, the interest in the study of various types of transients involving changes in the boron concentration inside the reactor, has led to an increase in the interest of developing and studying new models and tools that allow a correct study of boron transport. Therefore, a significant variety of different boron transport models and spatial difference schemes are available in the thermal-hydraulic codes, as TRACE. According to this interest, in this work it will be compared the results obtained using the different boron transport models implemented in the NRC thermal-hydraulic code TRACE. To do this, a set of models have been created using the different options and configurations that could have influence in boron transport. These models allow to reproduce a simple event of filling or emptying the boron concentration in a long pipe. Moreover, with the aim to compare the differences obtained when one-dimensional or three-dimensional components are chosen, it has modeled many different cases using only pipe components or a mix of pipe and vessel components. In addition, the influence of the void fraction in the boron transport has been studied and compared under close conditions to BWR commercial model. A final collection of the different cases and boron transport models are compared between them and those corresponding to the analytical solution provided by the Burgers equation. From this comparison, important conclusions are drawn that will be the basis of modeling the boron transport in TRACE adequately. (author)

  13. Determination of boron over a large dynamic range by prompt-gamma activation analysis

    International Nuclear Information System (INIS)

    Harrison, R.K.; Landsberger, S.

    2009-01-01

    An evaluation of the PGAA method for the determination of boron across a wide dynamic range of concentrations was performed for trace levels up to 5 wt.% boron. This range encompasses a transition from neutron transparency to significant self- shielding conditions. To account for self-shielding, several PGAA techniques were employed. First, a calibration curve was developed in which a set of boron standards was tested and the count rate to boron mass curve was determined. This set of boron measurements was compared with an internal standard self-shielding correction method and with a method for determining composition using PGAA peak ratios. The advantages and disadvantages of each method are analyzed. The boron concentrations of several laboratory-grade chemicals and standard reference materials were measured with each method and compared. The evaluation of the boron content of nanocrystalline transition metals prepared with a boron-containing reducing agent was also performed with each of the methods tested. Finally, the k 0 method was used for non-destructive measurement of boron in catalyst materials for the characterization of new non-platinum fuel cell catalysts.

  14. Boron toxicity causes multiple effects on Malus domestica pollen tube growth

    Directory of Open Access Journals (Sweden)

    Kefeng eFang

    2016-02-01

    Full Text Available Boron is an essential micronutrient for plants. However, boron is also toxic to cells at high concentrations, although the mechanism of this stress is not known. This study aimed to evaluate the effect of boron stress on Malus domestica pollen tube growth and its possible regulatory pathway. Our results show that a high concentration of boron inhibited pollen germination and tube growth and led to the morphological abnormality of pollen tubes. Fluorescent labeling coupled with a scanning ion-selective electrode technique detected that boron stress could decrease [Ca2+]c and induce the disappearance of the [Ca2+]c gradient, which are critical for pollen tube polar growth. Actin filaments were therefore altered by boron stress. Immuno-localization and fluorescence labeling, together with Fourier-transform infrared analysis (FTIR, suggested that boron stress influenced the accumulation and distribution of callose, de-esterified pectins, esterified pectins and arabinogalactan proteins in pollen tubes. All of the above results provide new insights into the regulatory role of boron in pollen tube development. In summary, boron likely plays a structural and regulatory role in relation to [Ca2+]c, actin cytoskeleton and cell wall components and thus regulates Malus domestica pollen germination and tube polar growth.

  15. Boron Toxicity Causes Multiple Effects on Malus domestica Pollen Tube Growth.

    Science.gov (United States)

    Fang, Kefeng; Zhang, Weiwei; Xing, Yu; Zhang, Qing; Yang, Liu; Cao, Qingqin; Qin, Ling

    2016-01-01

    Boron is an important micronutrient for plants. However, boron is also toxic to cells at high concentrations, although the mechanism of this toxicity is not known. This study aimed to evaluate the effect of boron toxicity on Malus domestica pollen tube growth and its possible regulatory pathway. Our results showed that a high concentration of boron inhibited pollen germination and tube growth and led to the morphological abnormality of pollen tubes. Fluorescent labeling coupled with a scanning ion-selective electrode technique detected that boron toxicity could decrease [Ca(2+)]c and induce the disappearance of the [Ca(2+)]c gradient, which are critical for pollen tube polar growth. Actin filaments were therefore altered by boron toxicity. Immuno-localization and fluorescence labeling, together with fourier-transform infrared analysis, suggested that boron toxicity influenced the accumulation and distribution of callose, de-esterified pectins, esterified pectins, and arabinogalactan proteins in pollen tubes. All of the above results provide new insights into the regulatory role of boron in pollen tube development. In summary, boron likely plays a structural and regulatory role in relation to [Ca(2+)]c, actin cytoskeleton and cell wall components and thus regulates Malus domestica pollen germination and tube polar growth.

  16. 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

  17. 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 %.

  18. Mathematical modeling based evaluation and simulation of boron removal in bioelectrochemical systems.

    Science.gov (United States)

    Ping, Qingyun; Abu-Reesh, Ibrahim M; He, Zhen

    2016-11-01

    Boron removal is an arising issue in desalination plants due to boron's toxicity. As an emerging treatment concept, bioelectrochemical systems (BES) can achieve potentially cost-effective boron removal by taking advantage of cathodic-produced alkali. Prior studies have demonstrated successful removal of boron in microbial desalination cells (MDCs) and microbial fuel cells (MFCs), both of which are representative BES. Herein, mathematical models were developed to further evaluate boron removal by different BES and understand the key operating factors. The models delivered very good prediction of the boron concentration in the MDC integrated with Donnan Dialysis (DD) system with the lowest relative root-mean-square error (RMSE) of 0.00%; the predication of the MFC performance generated the highest RMSE of 18.55%. The model results of salt concentration, solution pH, and current generation were well fitted with experimental data for RMSE values mostly below 10%. The long term simulation of the MDC-DD system suggests that the accumulation of salt in the catholyte/stripping solution could have a positive impact on the removal of boron due to osmosis-driven convection. The current generation in the MDC may have little influence on the boron removal, while in the MFC the current-driven electromigration can contribute up to 40% of boron removal. Osmosis-induced convection transport of boron could be the major driving force for boron removal to a low level 22.2 in order to avoid boron accumulation in the anolyte effluent. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Influence of operating parameters on the arsenic and boron removal by electrocoagulation

    International Nuclear Information System (INIS)

    Can, B. Z.; Boncukcuoglu, R.; Bayar, S.; Bayhan, Y.K

    2016-01-01

    Despite their high boron contents, some boron deposits contain considerable amounts of arsenic. Its toxicology and health hazard also has been reported for many years. In this work arsenic and boron removal from synthetic water was studied on laboratory scale by electrocoagulation using aluminum electrodes. The influence of main operating parameters such as current density, stirring speed, supporting electrolyte type and concentration on the arsenic and boron removal was investigated. Waste water sample was prepared with initial arsenic concentration of 50 mg L/sup -1/ and boron concentration of 1000 mg L/sup -1/. Current density was varied from 0.18 to 4.28 mA cm/sup -2/, stirring speed was varied as 50, 150, 250, 350 rpm, NaCl, KCl and Na/sub 2/SO/sub 4/ were used as supporting electrolyte. The obtained experimental results showed that efficiency of arsenic and boron removal increased with increasing current density. As the current density increases, the potential difference applied to the system also increases the energy consumption. Increasing the supporting electrolyte concentration increased conductivity of solution and decreased energy consumption. The most favorable supporting electrolyte type was NaCl for arsenic and boron removal. The best stirring speed was 150 rpm for arsenic and boron removal. (author)

  20. Factors influencing voltammetric reduction of 5-nitroquinoline at boron-doped diamond electrodes

    Czech Academy of Sciences Publication Activity Database

    Vosáhlová, J.; Zavázalová, J.; Petrák, Václav; Schwarzová-Pecková, K.

    2016-01-01

    Roč. 147, č. 1 (2016), s. 21-29 ISSN 0026-9247 Institutional support: RVO:68378271 Keywords : voltammetry * boron-doped diamond electrode * boron concentration * reduction * electrochemistry Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 1.282, year: 2016

  1. 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.

  2. Boron isotope fractionation in column chromatography with glucamine type fibers

    International Nuclear Information System (INIS)

    Sonoda, Akinari; Makita, Yoji; Hirotsu, Takahiro

    2008-01-01

    Glucamine type polymers have specific affinity toward boric acid and borate ion. Among them, Chelest Fiber GRY-L showed larger fractionation for boron isotopes than other polymers in our previous study. For this study, we used Chelest Fibers with different fiber lengths (1.0 mm, 0.5 mm, and 0.3 mm) as column packing materials to perform chromatographic separation of boron isotopes. The shorter fiber has larger packing density when packed into the column using a dry method. The 0.3-mm-long fiber has a larger backpressure than fibers of other lengths. Boron adsorption capacities were measured using the breakthrough operation. At this time, the 0.5-mm-long fiber showed the highest capacity. When we measured the isotope ratio profile for fibers of different length using column chromatography, 0.5-mm-long fibers displayed the highest boron isotope fractionation. The 0.5-mm-long fiber is promising as a packing material of column chromatography for boron isotope separation. We also changed operation methods. The lower eluent concentration and the slower flow rate are suitable for boron isotope separation. (author)

  3. 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.

  4. Physical modelling of a rapid boron dilution transient

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, N.G.; Hemstroem, B.; Karlsson, R. [Vattenfall Utveckling AB, Aelvkarleby (Sweden); Jacobson, S. [Vattenfall AB, Ringhals, Vaeroebacka (Sweden)

    1995-09-01

    The analysis of boron dilution accidents in pressurised water reactors has traditionally assumed that mixing is instantaneous and complete everywhere, eliminating in this way the possibility of concentration inhomogeneities. Situations can nevertheless arise where a volume of coolant with a low boron concentration may eventually enter the core and generate a severe reactivity transient. The work presented in this paper deals with a category of Rapid Boron Dilution Events characterised by a rapid start of a Reactor Coolant Pump (RCP) with a plug of relatively unborated water present in the RCS pipe. Model tests have been made at Vattenfall Utveckling AB in a simplified 1:5 scale model of a Westinghouse PWR. Conductivity measurements are used to determine dimensionless boron concentration. The main purpose of this experimental work is to define an experimental benchmark against which a mathematical model can be tested. The final goal is to be able to numerically predict Boron Dilution Transients. This work has been performed as a part of a Co-operative Agreement with Electricite` de France (EDF).

  5. Improved Strategies and Optimization of Calibration Models for Real-time PCR Absolute Quantification

    Science.gov (United States)

    Real-time PCR absolute quantification applications rely on the use of standard curves to make estimates of DNA target concentrations in unknown samples. Traditional absolute quantification approaches dictate that a standard curve must accompany each experimental run. However, t...

  6. 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.

  7. 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.

  8. Microwave digestion techniques applied to determination of boron by ICP-AES in BNCT program

    International Nuclear Information System (INIS)

    Farias, Silvia S.; Di Santo, Norberto R.; Garavaglia, Ricardo N.; Pucci, Gladys N.; Batistoni, Daniel A.; Schwint, Amanda E.

    1999-01-01

    Recently, boron neutron capture therapy (BNCT) has merged as an interesting option for the treatment of some kind of tumors where established therapies show no success. A molecular boronated species, enriched in 10 B is administrated to the subject; it localizes in malignant tissues depending the kind of tumor and localization. Therefore, a very important fact in BNCT research is the detection of boron at trace or ultra trace levels precisely and accurately. This is extremely necessary as boronated species do localize in tumoral tissue and also localize in liver, kidney, spleen, skin, membranes. By this way, before testing a boronated species, it is mandatory to determine its biodistribution in a statistically meaning population, that is related with managing of a great number of samples. In the other hand, it is necessary to exactly predict when to begin the irradiation and to determine the magnitude of radiation to obtain the desired radiological dose for a specified mean boron concentration. This involves the determination of boron in whole blood, which is related with boron concentration in the tumor object of treatment. The methodology selected for the analysis of boron in whole blood and tissues must join certain characteristics: it must not be dependant of the chemical form of boron, it has to be fast and capable to determine boron accurately and precisely in a wide range of concentrations. The design and validation of experimental models involving animals in BNCT studies and the determination of boron in blood of animals and subjects upon treatment require reliable analytical procedures to determine boron quantitatively in those biologic materials. Inductively coupled plasma-atomic emission spectrometry (ICP-AES) using pneumatic nebulization is one of the most promising methods for boron analysis, but the sample must be liquid and have low solid concentration. In our case, biological tissues and blood, it is mandatory to mineralize and/or dilute samples

  9. Boron evaporation in thermally-driven seawater desalination: Effect of temperature and operating conditions

    KAUST Repository

    Alpatova, Alla; Alsaadi, Ahmad Salem; Ghaffour, NorEddine

    2018-01-01

    The volatilization of boron in thermal desalination processes, namely multi-stage flash (MSF) and air-gap membrane distillation (AGMD) was investigated for the first time. This phenomenon was observed at feed temperatures above 55 °C in both studied processes. In simulated MSF process with two feeds, model boric acid and Red Sea water, boron concentration in distillate increased with feed temperature increase from 55 °C to 104 °C because of the increase in boric acid vapor pressure. Salinity and pH were the main factors controlling boron evaporation. The achieved boron concentrations in simulated MSF process were consistent with those measured in distillate samples collected from commercial MSF plants. The AGMD process also revealed a strong influence of operating temperature on boron removal. However, unlike MSF process, the boron concentration in AGMD permeate decreased with the feed temperature increase from 55 °C to 80 °C due probably to increase in vapor production and corresponding permeate dilution. When AGMD was operated in concentrating mode at a constant feed temperature of 80 °C, permeate boron concentration increased with process time due to concentration polarization and membrane fouling. A 10% flux decline observed after 21 h was attributed to CaCO scaling on the membrane surface.

  10. Boron evaporation in thermally-driven seawater desalination: Effect of temperature and operating conditions.

    Science.gov (United States)

    Alpatova, A; Alsaadi, A; Ghaffour, N

    2018-06-05

    The volatilization of boron in thermal desalination processes, namely multi-stage flash (MSF) and air-gap membrane distillation (AGMD) was investigated for the first time. This phenomenon was observed at feed temperatures above 55 °C in both studied processes. In simulated MSF process with two feeds, model boric acid and Red Sea water, boron concentration in distillate increased with feed temperature increase from 55 °C to 104 °C because of the increase in boric acid vapor pressure. Salinity and pH were the main factors controlling boron evaporation. The achieved boron concentrations in simulated MSF process were consistent with those measured in distillate samples collected from commercial MSF plants. The AGMD process also revealed a strong influence of operating temperature on boron removal. However, unlike MSF process, the boron concentration in AGMD permeate decreased with the feed temperature increase from 55 °C to 80 °C due probably to increase in vapor production and corresponding permeate dilution. When AGMD was operated in concentrating mode at a constant feed temperature of 80 °C, permeate boron concentration increased with process time due to concentration polarization and membrane fouling. A 10% flux decline observed after 21 h was attributed to CaCO 3 scaling on the membrane surface. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. Effects of boron on structure and antioxidative activities of spleen in rats.

    Science.gov (United States)

    Hu, Qianqian; Li, Shenghe; Qiao, Enmei; Tang, Zhongtao; Jin, Erhui; Jin, Guangming; Gu, Youfang

    2014-04-01

    In order to determine the relationship between boron and development of the spleen, especially in the promoting biological effects, we examined the effects of different levels of boron on weight, organ index, microstructure, and antioxidative activities of the spleen in rats. Sprague-Dawley (SD) rats were selected and treated with different concentrations of boron, and then, the organs were resected and weighed. One half of the tissue was fixed and embedded in paraffin to observe tissue structure changes. The other half of the tissue was homogenated for determining the antioxidant activities. The results showed that 40 mg/L of boron could increase weight, organ indexes, and antioxidant capacity of spleens and improve the spleen tissue structure, while the boron concentration above 80 mg/L could decrease weight, organ indexes, and antioxidant capacity of spleens and damage the spleen tissue structure. The higher the concentration, the more serious the damage was. Especially at the concentration of 640 mg/L, it could significantly inhibit the development of the spleen and even exhibit toxic effect. Hence, low boron concentration played a protective role in the development of the spleen, while high boron concentration could damage the organs and even produce toxic effect.

  12. Boron evaporation in thermally-driven seawater desalination: Effect of temperature and operating conditions

    KAUST Repository

    Alpatova, Alla

    2018-03-26

    The volatilization of boron in thermal desalination processes, namely multi-stage flash (MSF) and air-gap membrane distillation (AGMD) was investigated for the first time. This phenomenon was observed at feed temperatures above 55 °C in both studied processes. In simulated MSF process with two feeds, model boric acid and Red Sea water, boron concentration in distillate increased with feed temperature increase from 55 °C to 104 °C because of the increase in boric acid vapor pressure. Salinity and pH were the main factors controlling boron evaporation. The achieved boron concentrations in simulated MSF process were consistent with those measured in distillate samples collected from commercial MSF plants. The AGMD process also revealed a strong influence of operating temperature on boron removal. However, unlike MSF process, the boron concentration in AGMD permeate decreased with the feed temperature increase from 55 °C to 80 °C due probably to increase in vapor production and corresponding permeate dilution. When AGMD was operated in concentrating mode at a constant feed temperature of 80 °C, permeate boron concentration increased with process time due to concentration polarization and membrane fouling. A 10% flux decline observed after 21 h was attributed to CaCO scaling on the membrane surface.

  13. Effect of exogenous supply of boron on nodule development in pea (pisum sativum L.)

    International Nuclear Information System (INIS)

    Qasim, M.; Khan, Z.U.D.; Syed, H.R.; Mehmood, F.

    2011-01-01

    Exogenous supply of boron was evaluated on the seeds of Pisum sativum L. inoculated with Rhizobium leguminosarum and grown in aqua-culture. The liquid nutrition medium contained six boron concentrations (control, 1, 1.86, 2.86, 3.86, and 4.86 mg L/sup -1/ ). The results obtained from the present work showed that number of nodules, size of nodules and weight of boron treatment. Toxic effect of high concentration of boron (4.86 mg L/sup -1/ ) nodules exhibit great improvement in 2.86 mg L /sup-1/ was also recorded. There was significant reduction as compare to control in nodule weight, size and numbers. This fact becomes clear while observing the nodules growing in the boron free culture, which did not develop extensively. The comparison of the transverse sections of root-nodule area, from nutrient solutions with various boron concentrations showed that in the absence of boron, there was a considerable hypertrophy in cambial cells and a frequent disintegration of phloem and ground tissue along with xylem. The disintegration of the tissue seems to be linked with nodule bacteria. The nodular bacteria are considered to assume a parasitic habit in the absence of boron. (author)

  14. Cryogenic, Absolute, High Pressure Sensor

    Science.gov (United States)

    Chapman, John J. (Inventor); Shams. Qamar A. (Inventor); Powers, William T. (Inventor)

    2001-01-01

    A pressure sensor is provided for cryogenic, high pressure applications. A highly doped silicon piezoresistive pressure sensor is bonded to a silicon substrate in an absolute pressure sensing configuration. The absolute pressure sensor is bonded to an aluminum nitride substrate. Aluminum nitride has appropriate coefficient of thermal expansion for use with highly doped silicon at cryogenic temperatures. A group of sensors, either two sensors on two substrates or four sensors on a single substrate are packaged in a pressure vessel.

  15. 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.)

  16. Boron Stress Activates the General Amino Acid Control Mechanism and Inhibits Protein Synthesis

    Science.gov (United States)

    Uluisik, Irem; Kaya, Alaattin; Fomenko, Dmitri E.; Karakaya, Huseyin C.; Carlson, Bradley A.; Gladyshev, Vadim N.; Koc, Ahmet

    2011-01-01

    Boron is an essential micronutrient for plants, and it is beneficial for animals. However, at high concentrations boron is toxic to cells although the mechanism of this toxicity is not known. Atr1 has recently been identified as a boron efflux pump whose expression is upregulated in response to boron treatment. Here, we found that the expression of ATR1 is associated with expression of genes involved in amino acid biosynthesis. These mechanisms are strictly controlled by the transcription factor Gcn4 in response to boron treatment. Further analyses have shown that boron impaired protein synthesis by promoting phosphorylation of eIF2α in a Gcn2 kinase dependent manner. The uncharged tRNA binding domain (HisRS) of Gcn2 is necessary for the phosphorylation of eIF2α in the presence of boron. We postulate that boron exerts its toxic effect through activation of the general amino acid control system and inhibition of protein synthesis. Since the general amino acid control pathway is conserved among eukaryotes, this mechanism of boron toxicity may be of general importance. PMID:22114689

  17. Boron stress activates the general amino acid control mechanism and inhibits protein synthesis.

    Directory of Open Access Journals (Sweden)

    Irem Uluisik

    Full Text Available Boron is an essential micronutrient for plants, and it is beneficial for animals. However, at high concentrations boron is toxic to cells although the mechanism of this toxicity is not known. Atr1 has recently been identified as a boron efflux pump whose expression is upregulated in response to boron treatment. Here, we found that the expression of ATR1 is associated with expression of genes involved in amino acid biosynthesis. These mechanisms are strictly controlled by the transcription factor Gcn4 in response to boron treatment. Further analyses have shown that boron impaired protein synthesis by promoting phosphorylation of eIF2α in a Gcn2 kinase dependent manner. The uncharged tRNA binding domain (HisRS of Gcn2 is necessary for the phosphorylation of eIF2α in the presence of boron. We postulate that boron exerts its toxic effect through activation of the general amino acid control system and inhibition of protein synthesis. Since the general amino acid control pathway is conserved among eukaryotes, this mechanism of boron toxicity may be of general importance.

  18. Boron accumulation by Lemna minor L. under salt stress.

    Science.gov (United States)

    Liu, Chunguang; Gu, Wancong; Dai, Zheng; Li, Jia; Jiang, Hongru; Zhang, Qian

    2018-06-12

    Excess boron (B) is toxic to aquatic organisms and humans. Boron is often present in water with high salinity. To evaluate the potential of duckweed (Lemna minor L.) for removing B from water under salt stress, we cultured duckweed in water with 2 mg/L of B and sodium chloride (NaCl) concentrations ranging from 0 to 200 mM for 4 days. The results show that with increasing salinity, the capacity of L. minor to accumulate B initially decreased and then increased. L. minor used different mechanisms to accumulate boron at lower and higher levels of salt stress. The growth and chlorophyll synthesis of L. minor were significantly inhibited when the concentration of NaCl reached 100 mM. Our results suggest that L. minor is suitable for the accumulation of B when NaCl salinity is below 100 mM.

  19. Biological effects of tolerable level chronic boron intake on transcription factors.

    Science.gov (United States)

    Orenay Boyacioglu, Seda; Korkmaz, Mehmet; Kahraman, Erkan; Yildirim, Hatice; Bora, Selin; Ataman, Osman Yavuz

    2017-01-01

    The mechanism of boron effect on human transcription and translation has not been fully understood. In the current study it was aimed to reveal the role of boron on the expression of certain transcription factors that play key roles in many cellular pathways on human subjects chronically exposed to low amounts of boron. The boron concentrations in drinking water samples were 1.57±0.06mg/l for boron group while the corresponding value for the control group was 0.016±0.002mg/l. RNA isolation was performed using PAX gene RNA kit on the blood samples from the subjects. The RNA was then reverse transcribed into cDNA and analyzed using the Human Transcription Factors RT 2 Profiler™ PCR Arrays. While the boron amount in urine was detected as 3.56±1.47mg/day in the boron group, it was 0.72±0.30mg/day in the control group. Daily boron intake of the boron and control groups were calculated to be 6.98±3.39 and 1.18±0.41mg/day, respectively. The expression levels of the transcription factor genes were compared between the boron and control groups and no statistically significant difference was detected (P>0.05). The data suggest that boron intake at 6.98±3.39mg/day, which is the dose at which beneficial effects might be seen, does not result in toxicity at molecular level since the expression levels of transcription factors are not changed. Although boron intake over this level will seem to increase RNA synthesis, further examination of the topic is needed using new molecular epidemiological data. Copyright © 2016 Elsevier GmbH. All rights reserved.

  20. 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.

  1. Dependence of reaction pressure on deposition and properties of boron-doped freestanding diamond films

    International Nuclear Information System (INIS)

    Li Liuan; Li Hongdong; Lue Xianyi; Cheng Shaoheng; Wang Qiliang; Ren Shiyuan; Liu Junwei; Zou Guangtian

    2010-01-01

    In this paper, we investigate the reaction pressure-dependent growth and properties of boron-doped freestanding diamond films, synthesized by hot filament chemical vapor deposition (HFCVD) at different boron-doping levels. With the decrease in pressure, the growth feature of the films varies from mixed [1 1 1] and [1 1 0] to dominated [1 1 1] texture. The low reaction pressure, as well as high boron-doping level, results in the increase (decrease) of carrier concentration (resistivity). The high concentration of atomic hydrogen in the ambient and preferable [1 1 1] growth, due to the low reaction pressure, is available for the enhancement of boron doping. The estimated residual stress increases with increase in the introducing boron level.

  2. Thermal desorption spectroscopy of boron/carbon films after keV deuterium irradiation

    International Nuclear Information System (INIS)

    Yamaki, T.; Gotoh, Y.; Ando, T.; Jimbou, R.; Ogiwara, N.; Saidoh, M.

    1994-01-01

    Thermal desorption spectroscopy (TDS) of D 2 and CD 4 was done on boron/carbon films (B/(B+C)=0-74%), after 3 keV D 3 + irradiation to 4.5x10 17 D/cm 2 at 473 K. The D 2 desorption peaks were observed at 1050, 850 and 650 K. For a sputter B/C film (0%), only the 1050 K peak was observed. With increasing boron concentration to 3%, a sharp peak appeared at 850 K, the intensity of which was found to increase with increasing boron concentration to 23%, and then to decrease at 74%. The 650 K shoulder, which was observed for high boron concentration specimens, was speculated to be deuterium trapped by boron atoms in the boron clusters. The relative amount of CD 4 desorption was found to decrease with increasing boron concentration, which was attributed to the decrease in the trapped deuterium concentration in the implantation layer at temperatures at which CD 4 desorption proceeds. ((orig.))

  3. Structure and absolute configuration of Jurassic polyketide-derived spiroborate pigments obtained from microgram quantities.

    OpenAIRE

    Wolkenstein, K.; Sun , H.; Falk, H.; Griesinger, C.

    2015-01-01

    Complete structural elucidation of natural products is often challenging due to structural complexity and limited availability. This is true for present-day secondary metabolites, but even more for exceptionally preserved secondary metabolites of ancient organisms that potentially provide insights into the evolutionary history of natural products. Here, we report the full structure and absolute configuration of the borolithochromes, enigmatic boron-containing pigments from a Jurassic putative...

  4. Alleviation of Boron Stress through Plant Derived Smoke Extracts in Sorghum bicolor

    Directory of Open Access Journals (Sweden)

    Pirzada Khan

    2014-08-01

    Full Text Available Boron is an essential micronutrient necessary for plant growth at optimum concentration. However, at high concentrations boron affects plant growth and is toxic to cells. Aqueous extract of plant-derived smoke has been used as a growth regulator for the last two decades to improve seed germination and seedling vigor. It has been established that plant-derived smoke possesses some compounds that act like plant growth hormones. The present research was the first comprehensive attempt to investigate the alleviation of boron stress with plant-derived smoke aqueous extract on Sorghum (Sorghum bicolor seed. Smoke extracts of five plants, i.e. Cymbopogon jwarancusa, Eucalyptus camaldulensis, Peganum harmala, Datura alba and Melia azedarach each with six dilutions (Concentrated, 1:100, 1:200, 1:300, 1:400 and 1:500 were used. While boron solutions at concentrations of 5, 10, 15, 20 and 25 ppm were used for stress. Among the dilutions of smoke, 1:500 of E. camaldulensis significantly increased germination percentage, root and shoot length, number of secondary roots and fresh weight of root and shoot while, boron stress reduced growth of Sorghum. It was observed that combined effect of boron solution and E. camaldulensis smoke extract overcome inhibition and significantly improved plant growth. Present research work investigated that the smoke solution has the potential to alleviate boron toxicity by reducing the uptake of boron by maintaining integrity of plant cell wall. The present investigation suggested that plant derived smoke has the potential to alleviate boron stress and can be used to overcome yield losses caused by boron stress to plants.

  5. Treatment planning figures of merit in thermal and epithermal boron capture therapy of brain tumours

    Energy Technology Data Exchange (ETDEWEB)

    Wallace, S.A.; Mathur, J.N. (Wollongong Univ., NSW (Australia)); Allen, B.J. (Ansto PMB 1 Menai, NSW (Australia). Biomedicine and Health)

    1994-05-01

    The boron neutron capture therapy (BNCT) figures of merit of advantage depth, therapeutic depth, modified advantage depth and maximum therapeutic depth have been studied as functions of [sup 10]B tumour to blood ratios and absolute levels. These relationships were examined using the Monte Carlo neutron photon transport code, MCNP, with an ideal 18.4 cm diameter neutron beam incident laterally upon an ellipsoidal neutron photon brain-equivalent model. Mono-energetic beams of 0.025 eV (thermal) and 35 eV (epithermal) were simulated. Increasing the tumour to blood [sup 10]B ratio predictably increases all figures of merit. [sup 10]B concentration was also shown to have a strong bearing on the figures of merit when low levels were present in the system. This is the result of a non-[sup 10]B dependent background dose. At higher levels however, the concentration of [sup 10]B has a diminishing influence. For boron sulphydryl (BSH), little advantage is gained by extending the blood [sup 10]B level beyond 30 ppm, whilst for D, L,-p-boronophenylalanine (BPA) this limit is 10 ppm. Applying the epithermal beam under identical conditions, the therapeutic depth reaches the brain mid-line with a tumour to blood [sup 10]B ratio of only 5.7 for BPA. For BSH, the maximum therapeutic depth reaches the brain mid-line with a tumour to blood ratio of only 1.9 with 30 ppm in the blood. Human data for these compounds are very close to these requirements. (author).

  6. 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

  7. 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.

  8. Intracellular targeting of mercaptoundecahydrododecaborate (BSH) to malignant glioma by transferrin-PEG liposomes for boron neutron capture therapy (BNCT)

    International Nuclear Information System (INIS)

    Doi, Atsushi; Miyatake, Shin-ichi; Iida, Kyouko

    2006-01-01

    Malignant glioma is one of the most difficult tumor to control with usual therapies. In our institute, we select boron neutron capture therapy (BNCT) as an adjuvant radiation therapy after surgical resection. This therapy requires the selective delivery of high concentration of 10 B to malignant tumor tissue. In this study, we focused on a tumor-targeting 10 B delivery system (BDS) for BNCT that uses transferrin-conjugated polyethylene-glycol liposome encapsulating BSH (TF-PEG liposome-BSH) and compared 10 B uptake of the tumor among BSH, PEG liposome-BSH and TF-PEG liposome-BSH. In vitro, we analyzed 10 B concentration of the cultured human U87Δ glioma cells incubated in medium containing 20 μg 10 B/ml derived from each BDS by inductively coupled plasma atomic emission spectrometry (ICP-AES). In vivo, human U87Δ glioma-bearing nude mice were administered with each BDS (35mg 10 B/kg) intravenously. We analyzed 10 B concentration of tumor, normal brain and blood by ICP-AES. The TF-PEG liposome-BSH showed higher absolute concentration more than the other BDS. Moreover, TF-PEG liposome-BSH decreased 10 B concentration in blood and normal tissue while it maintained high 10 B concentration in tumor tissue for a couple of days. This showed the TF-PEG liposome-BSH caused the selective delivery of high concentration of 10 B to malignant tumor tissue. The TF-PEG liposome-BSH is more potent BDS for BNCT to obtain absolute high 10 B concentration and good contrast between tumor and normal tissue than BSH and PEG liposome-BSH. (author)

  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. Boron Removal from Seawater by Thin-Film Composite Reverse Osmosis Membranes

    KAUST Repository

    Al Sunbul, Yasmeen

    2018-04-01

    Reverse Osmosis membranes have been successfully proven to remove almost 99% of chemicals dissolved in seawater. However, removal of certain trace elements, such as boron is challenging and relatively low for seawater reverse osmosis desalination plants compared to thermal desalination plants. Boron is naturally occurring and is present in seawater at an average concentration of 4.5-5 mg/L. While boron is a vital element, its toxicity has been proven on crops, animals and possibly humans. Additionally, boron should be removed to comply with the current guideline value of 0.5 mg/L, for drinking water, issued by the World Health Organization (WHO), which is barely attained by a single-pass process seawater reverse osmosis plant. Currently, multipass reverse osmosis membrane operations with pH modifications are the only valid method for boron removal. However, this is not economically efficient as it requires higher energy and chemicals consumptions. The objective of this study was to investigate boron removal by commercial TFC RO membranes in addition to custom-made KAUST-synthesized TFC membrane. Five membrane samples were examined: Toray, Sepro, Koch, and KAUST in-house synthesized membrane. Three different feed pH conditions were used: pH6, pH8, and pH10. Filtration experiments were conducted in two parts. In experiment 1, all five membranes were examined for boron rejection in a dead-end permeation system, whereas in experiment 2 the two membranes with the highest boron rejection from experiment 1 were tested in a cross-flow system. Permeate and feed samples were taken continuously and analyzed for boron concentration, rejection calculation. Membrane surfaces were characterized according to hydrophilicity, roughness and surface charge. The results showed for all the tested membranes that boron rejection increased as the feed pH increased. KAUST, defect-free TFC, showed the highest performance for boron rejection for all pH conditions, although, it shows the

  11. Absolute flux scale for radioastronomy

    International Nuclear Information System (INIS)

    Ivanov, V.P.; Stankevich, K.S.

    1986-01-01

    The authors propose and provide support for a new absolute flux scale for radio astronomy, which is not encumbered with the inadequacies of the previous scales. In constructing it the method of relative spectra was used (a powerful tool for choosing reference spectra). A review is given of previous flux scales. The authors compare the AIS scale with the scale they propose. Both scales are based on absolute measurements by the ''artificial moon'' method, and they are practically coincident in the range from 0.96 to 6 GHz. At frequencies above 6 GHz, 0.96 GHz, the AIS scale is overestimated because of incorrect extrapolation of the spectra of the primary and secondary standards. The major results which have emerged from this review of absolute scales in radio astronomy are summarized

  12. 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

  13. 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.

  14. 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

  15. Improved ductility of Ni3Si by microalloying with boron or carbon

    International Nuclear Information System (INIS)

    Taub, A.I.; Briant, C.L.

    1989-01-01

    The effects of boron and carbon additions on the tendency for intergranular fracture in trinickel silicide intermetallics are reported. Melt spinning of Ni 77 Si 23 alloyed with 0.1 at. pct boron results in full bend ductility and complete transgranular fracture compared with brittle intergranular fracture for the unmodified compound. Alloying with 0.1 at. pct carbon also produced full bend ductility but a mixed mode failure (30 pct transgranular). For both carbon and boron additions, reducing the Ni concentration of the base compound results in a greater percentage of intergranular fracture. For Ni 77 Si 23 , the solubility limit is between 0.1 and 0.2 t. pct boron. For compounds with silicon concentrations of 23.5 and 24.0 at. pct, the solubility limit is less than 0.1 at. pct boron. Boron additions above the solubility limit result in Ni 3 B precipitates which degrade the bend ductility and increase the percentage of intergranular fracture. Alloying with carbon above the solubility limit ( 77 Si 23 , increasing the carbon concentration from 0.1 to 1.0 at. pct resulted in no change in the ductility. Auger examination of the grain boundary composition showed strong segregation of both boron and carbon. Enrichment in silicon concentration was also observed

  16. Boron exposure assessment using drinking water and urine in the North of Chile.

    Science.gov (United States)

    Cortes, S; Reynaga-Delgado, E; Sancha, A M; Ferreccio, C

    2011-12-01

    Boron is an essential trace element for plants and humans however it is still an open question what levels of boron are actually safe for humans. This study, conducted between 2006 and 2010, measured exposure levels of boron in drinking water and urine of volunteers in Arica, an area in the North of Chile with high levels of naturally occurring boron. Samples were taken of tap and bottled water (173 and 22, respectively), as well as urine from 22 volunteers, and subsequently analyzed by inductively coupled plasma spectroscopy (ICP-OES). Boron varied in public tap water from 0.22 to 11.3mgL(-1), with a median value of 2.9mgL(-1), while concentrations of boron in bottled water varied from 0.01 to 12.2mgL(-1). Neither tap nor bottled water samples had concentrations of boron within WHO recommended limits. The concentration of boron in urine varied between 0.45 and 17.4mgL(-1), with a median of 4.28mgL(-1) and was found to be correlated with tap water sampled from the homes of the volunteers (r=0.64). Authors highly recommend that in northern Chile - where levels of boron are naturally high - that the tap and bottled water supplies be monitored in order to protect public health and that regulatory standards also be established for boron in drinking water in order to limit exposure. Copyright © 2011 Elsevier B.V. All rights reserved.

  17. Boron, phosphorus, and gallium determination in silicon crystals doped with gallium

    International Nuclear Information System (INIS)

    Shklyar, B.L.; Dankovskij, Yu.V.; Trubitsyn, Yu.V.

    1989-01-01

    When studying IR transmission spectra of silicon doped with gallium in the range of concentrations 1 x 10 14 - 5 x 10 16 cm -3 , the possibility to quantity at low (∼ 20 K) temperatures residual impurities of boron and phosphorus is ascertained. The lower determination limit of boron is 1 x 10 12 cm -3 for a sample of 10 nm thick. The level of the impurities in silicon crystals, grown by the Czochralski method and method of crucible-free zone melting, is measured. Values of boron and phosphorus concentrations prior to and after their alloying with gallium are compared

  18. Boron toxicity in banana (Musa AAA) plantations of Costa Rica

    International Nuclear Information System (INIS)

    Vargas, Alfonso; Serrano, Edgardo; Arias, Fulvio; Arias M, Oscar

    2007-01-01

    A marginal, irregular and continuous necrosis was observed in the leaves of in banana plants (Musa AAA, cvs. Grande Naine and Valery), This necrosis was developed from an irregular chlorotic area, from the edge towards the internal part of the leaf blade. The central portion of the leaf kept the original green color. Soil and foliar analyses showed that symptoms were caused by high boron concentrations, probably due to excessive soil or foliage applications of the nutriment, or to the effect of very frequent applications of boron during fertigation, combined with a decrease of calcium in the leaf. (author) [es

  19. Separation of boron isotopes using NMG type anion exchange resin

    International Nuclear Information System (INIS)

    Itagaki, Takaharu; Kosuge, Masao; Fukuda, Junji; Fujii, Yasuhiko.

    1992-01-01

    Ion exchange separation of boron isotopes (B-10 and B-11) has been studied by using a special boron selective ion exchange resin; NMG (n-methyl glucamine)-type anion exchange resin. The resin has shown a large isotope separation coefficient of 1.02 at the experimental conditions of temperature, 80degC, and boric acid concentration, 0.2 M (mole/dm 3 ). Enriched B-10 (92%) was obtained after the migration of 1149 m by a recyclic operation of ion exchange columns in a merry-go-round method. (author)

  20. 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.

  1. 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.)

  2. Synovectomy by neutron capture in boron

    International Nuclear Information System (INIS)

    Vega C, H.R.

    2002-01-01

    , without iron and boron and with two boron concentrations. (Author)

  3. Absolute measurement of environmental radon content

    International Nuclear Information System (INIS)

    Ji Changsong

    1987-01-01

    A transportable meter for environmental radon measurement with a 40 liter decay chamber is designed on the principle of Thomas two-filter radon content absolute measurement. The sensitivity is 0.37 Bq·m -3 with 95% confidence level. This paper describes the experimental method of measuremment and it's intrinsic uncertainty. The typical intrinsic uncertainty (for n x 3.7 Bq·m -3 radon concentration) is <10%. The parameter of exit filter effeciency is introduced into the formula, and the verification is done for the case when the diameter of the exit filter is much less than the inlet one

  4. 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

  5. Relativistic Absolutism in Moral Education.

    Science.gov (United States)

    Vogt, W. Paul

    1982-01-01

    Discusses Emile Durkheim's "Moral Education: A Study in the Theory and Application of the Sociology of Education," which holds that morally healthy societies may vary in culture and organization but must possess absolute rules of moral behavior. Compares this moral theory with current theory and practice of American educators. (MJL)

  6. Forcing absoluteness and regularity properties

    NARCIS (Netherlands)

    Ikegami, D.

    2010-01-01

    For a large natural class of forcing notions, we prove general equivalence theorems between forcing absoluteness statements, regularity properties, and transcendence properties over L and the core model K. We use our results to answer open questions from set theory of the reals.

  7. Some absolutely effective product methods

    Directory of Open Access Journals (Sweden)

    H. P. Dikshit

    1992-01-01

    Full Text Available It is proved that the product method A(C,1, where (C,1 is the Cesàro arithmetic mean matrix, is totally effective under certain conditions concerning the matrix A. This general result is applied to study absolute Nörlund summability of Fourier series and other related series.

  8. Depth profiling of hydrogen passivation of boron in Si(100)

    Science.gov (United States)

    Huang, L. J.; Lau, W. M.; Simpson, P. J.; Schultz, P. J.

    1992-08-01

    The properties of SiO2/p-Si were studied using variable-energy positron-annihilation spectroscopy and Raman spectroscopy. The oxide film was formed by ozone oxidation in the presence of ultraviolet radiation at room temperature. Both the positron-annihilation and Raman analyses show that chemical cleaning of boron-doped p-type Si(100) using concentrated hydrofluoric acid prior to the oxide formation leads to hydrogen incorporation in the semiconductor. The incorporated hydrogen passivates the boron dopant by forming a B-H complex, the presence of which increases the broadening of the line shape in the positron-annihilation analysis, and narrows the linewidth of the Raman peak. Annealing of the SiO2/Si sample at a moderate temperature of 220 °C in vacuum was found sufficient to dissociate the complex and reactivate the boron dopant.

  9. Reproductive toxicity in boron exposed workers in Bandirma, Turkey.

    Science.gov (United States)

    Başaran, Nurşen; Duydu, Yalçin; Bolt, Hermann M

    2012-06-01

    Boric acid and sodium borates have been considered as being "toxic to reproduction and development", following results of animal studies with high doses. However unfavorable effects of boron exposure on reproduction and development have not been proved in epidemiological studies so far. The aim of the present study was to investigate the reproductive toxicity indicators in highly exposed workers employed in a boric acid production plant in Bandırma, Turkey. Two hundred and four workers participated in this study. The mean blood boron concentration of the high exposure group of workers was 223.89 ± 69.49 (152.82-454.02)ng/g. Unfavorable effects of boron exposure on the reproductive toxicity indicators were not observed. Copyright © 2012 Elsevier GmbH. All rights reserved.

  10. A density functional theory study of new boron nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Zhao-Hua [Shijiazhuang Institute of Technology, Shijiazhuang (China); Xie, Zun [Hebei Normal Univ., Shijiazhuang (China). College of Physics Science and Information Engineering and Hebei Advanced Thin Films Lab.

    2017-07-01

    Using first-principles calculations, a series of new boron nanotubes (BNTs), which show various electronic properties, were theoretically predicted. Stable nanotubes with various chiral vectors and diameters can be formed by rolling up the boron sheet with relative stability [H. Tang and S. I. Beigi, Phys. Rev. B 82, 115412 (2010).]. By increasing the diameter for BNT, the stability is enhanced. The calculated density of states and band structures demonstrate that all the predicted BNTs are metallic, regardless of their diameter and chirality. The multicentre chemical bonds of the relatively stable boron sheet and BNTs are analysed using the deformation electron density. Within our study, the BNTs all have metallic conductive characteristics, in addition to having a low effective quality and high carrier concentration, which are very good nanoconductive material properties and could be combined to form high-power electrodes for lithium-ion batteries such as those used in many modern electronics.

  11. In vitro and in vivo studies in boron neutron capture therapy of malignant melanoma

    International Nuclear Information System (INIS)

    Allen, B.J.

    1982-01-01

    A multidisciplinary research project in boron neutron capture therapy of malignant melanoma is under consideration by the Australian Atomic Energy Commission. This paper reviews the biochemistry of melanoma and the properties of some melanoma-affined radiopharmaceuticals and their boron analogues. Human cell lines are being used for in vitro tests of uptake and incorporation of some of these compounds, and selected lines will then be implanted in nude mice for in vivo distribution studies. The fidelity of human melanoma xenografts in nude mice has been well studied, and results are reviewed in this paper. Boron concentration will be measured directly by plasma arc emission spectroscopy or liquid scintillation counting with 14 C-labelled boron analogues. Track-etch techniques will be used for the microscopic determination of boron in tumor sections. Neutron irradiation and radiobiology experiments are outlined

  12. Subcellular boron and fluorine distributions with SIMS ion microscopy in BNCT and cancer research

    Energy Technology Data Exchange (ETDEWEB)

    Subhash Chandra

    2008-05-30

    The development of a secondary ion mass spectrometry (SIMS) based technique of Ion Microscopy in boron neutron capture therapy (BNCT) was the main goal of this project, so that one can study the subcellular location of boron-10 atoms and their partitioning between the normal and cancerous tissue. This information is fundamental for the screening of boronated drugs appropriate for neutron capture therapy of cancer. Our studies at Cornell concentrated mainly on studies of glioblastoma multiforme (GBM). The early years of the grant were dedicated to the development of cryogenic methods and correlative microscopic approaches so that a reliable subcellular analysis of boron-10 atoms can be made with SIMS. In later years SIMS was applied to animal models and human tissues of GBM for studying the efficacy of potential boronated agents in BNCT. Under this grant the SIMS program at Cornell attained a new level of excellence and collaborative SIMS studies were published with leading BNCT researchers in the U.S.

  13. Determination of residual boron in thermally treated controlled-porosity glasses, by colorimetry, spectrography and isotachophoresis

    International Nuclear Information System (INIS)

    Dawidowicz, A.L.; Matusewicz, J.; Wysocka-Lisek, J.

    1989-01-01

    Controlled-porosity glasses (CPGs) are often applied as sorbents in chromatography. Besides having high thermal, chemical and mechanical resistance they are characterized by a very narrow pore-size distribution and the choice of mean pore diameter and porosity covers a wide range. In spite of these advantages, their range of use in chromatography is restricted because of their strong adsorption properties, which are connected with the presence of residual boron atoms in the porous CPG skeleton. The boron concentration on the CPG surface can be increased by proper thermal treatment. When CPGs are heated in the range 400-800 0 the residual boron atoms in the network diffuse from the bulk to the surface. The paper discusses the boron content in porous glasses of different mean pore diameters and the determination of the enrichment of boron on the GPG surface, by three independent methods: colorimetry, spectrography and isotachophoresis. (author)

  14. Investigation of boron conjugated thiouracil derivates for neutron capture therapy of melanoma

    International Nuclear Information System (INIS)

    Corderoy-Buck, S.; Allen, B.J.; Wilson, J.G.; Tjarks, W.; Gabel, D.; Barkla, D.; Patwardhan, A.; Chandler, A.; Moore, D.E.

    1990-01-01

    Boron conjugated thiouracil derivatives were investigated as possible agents for boron neutron capture therapy (BNCT) of melanoma. Nude mice bearing human or murine melanoma xenografts were used for biodistribution studies following i.p. or i.t. (intratumoural) injection of these drugs. Boron content was analysed by inductively coupled plasma atomic emission spectrometry. Wide variation between tumour lines was observed with respect to accumulation of these drugs, but they appear to offer potential as melanoma affined boron carriers if solubility problems are overcome by liposome entrapment. Pre-treatment to stimulate melanogenesis may also prove a useful adjunct in achieving the therapeutic concentrations of boron necessary for successful BNCT. 25 refs., 4 tabs., 3 figs

  15. Subcellular boron and fluorine distributions with SIMS ion microscopy in BNCT and cancer research

    International Nuclear Information System (INIS)

    Subhash, Chandra

    2008-01-01

    The development of a secondary ion mass spectrometry (SIMS) based technique of Ion Microscopy in boron neutron capture therapy (BNCT) was the main goal of this project, so that one can study the subcellular location of boron-10 atoms and their partitioning between the normal and cancerous tissue. This information is fundamental for the screening of boronated drugs appropriate for neutron capture therapy of cancer. Our studies at Cornell concentrated mainly on studies of glioblastoma multiforme (GBM). The early years of the grant were dedicated to the development of cryogenic methods and correlative microscopic approaches so that a reliable subcellular analysis of boron-10 atoms can be made with SIMS. In later years SIMS was applied to animal models and human tissues of GBM for studying the efficacy of potential boronated agents in BNCT. Under this grant the SIMS program at Cornell attained a new level of excellence and collaborative SIMS studies were published with leading BNCT researchers in the U.S.

  16. A study on the boron injection initiation temperature curve of BWR

    International Nuclear Information System (INIS)

    Wang, S.-J.; Chien, C.-S.; Fann, S.-Y.; Chiang, S.-C.

    2007-01-01

    Boron injection initiation temperature (BIIT) provides important information for the safe shutdown of the reactor using boron injection system during anticipated transient without scram (ATWS). The purpose of this paper is to study BIIT curve of boiling water reactor owners' group (BWROG). The unreasonable and non-conservative parts of BIIT are pointed out and suggested modifications are made. The starting reactor power of BIIT is increased in order to meet the actual application. The lower limit of suppression pool temperature of BIIT is revised for conservative operation during ATWS conditions. Analysis of the effects of maximum temperature capacity of the suppression chamber and concentration of boron in standby liquid control tank shows that BIIT is decreased by adopting a more conservative value of maximum temperature capacity of the suppression chamber. Consequently, early boron injection is anticipated. For system with automatic boron injection system, BIIT is not required

  17. 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)

  18. 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.

  19. 10B uptake by cells for boron neutron capture synovectomy

    International Nuclear Information System (INIS)

    Binello, E.; Yanch, J.C.; Shortkroff, S.

    2000-01-01

    Boron Neutron Capture Synovectomy (BNCS) proposes to use the 10 B(n,α) 7 Li reaction to ablate inflamed synovium (a tissue lining articular joints) in patients with Rheumatoid Arthritis. Boron uptake is an important parameter for treatment design. In this study, a simple method was developed to determine K 2 B 12 H 12 (KBH) uptake in vitro by non-adhering monocytic cells (representative of synovial cells in inflamed joints). Uptake was quantified as a function of incubation time and boron concentration, as well as following washout: no significant difference was found between incubation times tested; average uptake ranged from 55 to 60% of 10 B incubation concentrations varying from 1000 to 5000 ppm: approximately 15% of the 10 B concentration was measured upon re-incubation in boron-free medium. These results agree well with those obtained ex vivo using human arthritic synovium, a significant finding in light of the difficulty typically associated with obtaining such tissue. The full characterization of 10 B uptake for BNCS (with KBH) is discussed. (author)

  20. Method of accurate thickness measurement of boron carbide coating on copper foil

    Science.gov (United States)

    Lacy, Jeffrey L.; Regmi, Murari

    2017-11-07

    A method is disclosed of measuring the thickness of a thin coating on a substrate comprising dissolving the coating and substrate in a reagent and using the post-dissolution concentration of the coating in the reagent to calculate an effective thickness of the coating. The preferred method includes measuring non-conducting films on flexible and rough substrates, but other kinds of thin films can be measure by matching a reliable film-substrate dissolution technique. One preferred method includes determining the thickness of Boron Carbide films deposited on copper foil. The preferred method uses a standard technique known as inductively coupled plasma optical emission spectroscopy (ICPOES) to measure boron concentration in a liquid sample prepared by dissolving boron carbide films and the Copper substrates, preferably using a chemical etch known as ceric ammonium nitrate (CAN). Measured boron concentration values can then be calculated.

  1. Moral absolutism and ectopic pregnancy.

    Science.gov (United States)

    Kaczor, C

    2001-02-01

    If one accepts a version of absolutism that excludes the intentional killing of any innocent human person from conception to natural death, ectopic pregnancy poses vexing difficulties. Given that the embryonic life almost certainly will die anyway, how can one retain one's moral principle and yet adequately respond to a situation that gravely threatens the life of the mother and her future fertility? The four options of treatment most often discussed in the literature are non-intervention, salpingectomy (removal of tube with embryo), salpingostomy (removal of embryo alone), and use of methotrexate (MXT). In this essay, I review these four options and introduce a fifth (the milking technique). In order to assess these options in terms of the absolutism mentioned, it will also be necessary to discuss various accounts of the intention/foresight distinction. I conclude that salpingectomy, salpingostomy, and the milking technique are compatible with absolutist presuppositions, but not the use of methotrexate.

  2. Absolute magnitudes by statistical parallaxes

    International Nuclear Information System (INIS)

    Heck, A.

    1978-01-01

    The author describes an algorithm for stellar luminosity calibrations (based on the principle of maximum likelihood) which allows the calibration of relations of the type: Msub(i)=sup(N)sub(j=1)Σqsub(j)Csub(ij), i=1,...,n, where n is the size of the sample at hand, Msub(i) are the individual absolute magnitudes, Csub(ij) are observational quantities (j=1,...,N), and qsub(j) are the coefficients to be determined. If one puts N=1 and Csub(iN)=1, one has q 1 =M(mean), the mean absolute magnitude of the sample. As additional output, the algorithm provides one also with the dispersion in magnitude of the sample sigmasub(M), the mean solar motion (U,V,W) and the corresponding velocity ellipsoid (sigmasub(u), sigmasub(v), sigmasub(w). The use of this algorithm is illustrated. (Auth.)

  3. Absolute gravity measurements in California

    Science.gov (United States)

    Zumberge, M. A.; Sasagawa, G.; Kappus, M.

    1986-08-01

    An absolute gravity meter that determines the local gravitational acceleration by timing a freely falling mass with a laser interferometer has been constructed. The instrument has made measurements at 11 sites in California, four in Nevada, and one in France. The uncertainty in the results is typically 10 microgal. Repeated measurements have been made at several of the sites; only one shows a substantial change in gravity.

  4. The Absolute Immanence in Deleuze

    OpenAIRE

    Park, Daeseung

    2013-01-01

    The absolute immanence in Deleuze Daeseung Park Abstract The plane of immanence is not unique. Deleuze and Guattari suppose a multiplicity of planes. Each great philosopher draws new planes on his own way, and these planes constitute the "time of philosophy". We can, therefore, "present the entire history of philosophy from the viewpoint of the institution of a plane of immanence" or present the time of philosophy from the viewpoint of the superposition and of the coexistence of planes. Howev...

  5. Transient performance and design aspects of low boron PWR cores with increased utilization of burnable absorbers

    International Nuclear Information System (INIS)

    Papukchiev, Angel; Schaefer, Anselm

    2008-01-01

    In conventional pressurized water reactor (PWR) designs, soluble boron is used for reactivity control over core fuel cycle. As high boron concentrations have significant impact on reactivity feedback properties and core transient behaviour, design changes to reduce boron concentration in the reactor coolant are of general interest in view of improving PWR inherent safety. In order to assess the potential advantages of such 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 (Gd) and 805 (Er) ppm. An innovative low boron core design methodology was implemented combining a simplified reactivity balance search procedure with a core design approach based on detailed 3D diffusion calculations. Fuel cross sections needed for nuclear libraries were generated using the 2D lattice code HELIOS [2] and full core configurations were modelled with the 3D diffusion code QUABOX/CUBBOX [3]. For dynamic 3D calculations, the coupled code system ATHLET - QUABOX/CUBBOX was used [4]. The new cores meet German acceptance criteria regarding stuck rod, departure from nucleate boiling ratio (DNBR), shutdown margin, and maximal linear power. For the assessment of potential safety advantages of the new cores, comparative analyses were performed for three PWR core designs: the already mentioned two low boron designs and a standard design. The improved safety performance of the low boron cores in anticipated transients without scram (ATWS), boron dilution scenarios and beyond design basis accidents (BDBA) has already been reported in [1, 2 and 3]. This paper gives a short reminder on the results obtained. Moreover, it deals not only with the potential advantages, but also addresses the drawbacks of the new PWR configurations - complex core design, increased power

  6. Boron diffusion into nitrogen doped silicon films for P{sup +} polysilicon gate structures

    Energy Technology Data Exchange (ETDEWEB)

    Mansour, Farida; Mahamdi, Ramdane; Jalabert, Laurent; Temple-Boyer, Pierre

    2003-06-23

    This paper deals with the study of the boron diffusion in nitrogen doped silicon (NIDOS) deposited from disilane Si{sub 2}H{sub 6} and ammonia NH{sub 3} for the development of P{sup +} polysilicon gate metal oxide semiconductor (MOS) devices. NIDOS films with varied nitrogen content have been boron implanted, then annealed and finally analysed by secondary ion mass spectroscopy (SIMS). In order to simulate the experimental SIMS of boron concentration profiles in the NIDOS films, a model adapted to the particular conditions of the samples elaboration, i.e. the very high boron concentration and the nitrogen content, has been established. The boron diffusion reduction in NIDOS films with increasing nitrogen rates has been evidenced by the profiles as well as by the obtained diffusion coefficients, which shows that the nitrogen incorporation reduces the boron diffusion. This has been confirmed by capacitance-voltage (C-V) measurements performed on MOS capacitors: the higher the nitrogen content, the lower the flat-band voltage. Finally, these results demonstrate that the improvement of the gate oxide quality occurs with the suppression of the boron penetration.

  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. The Effect of Nitrogen Application on Boron Toxicity Reduction in Pistachio (Pistacia vera cv. Badami-Zarand Saplings

    Directory of Open Access Journals (Sweden)

    babak motesharezadeh

    2017-02-01

    Full Text Available Introduction: Boron is one of the seven essential microelements for the natural growth of plants. The toxicity of this element occurs in arid and semi-arid regions, which is because of its high level in soils and the irrigation water of mentioned regions. The aim of this study was to evaluate the effect of nitrogen application on boron toxicity tolerance in pistachio, Badami-Zarand variety. The effects of three nitrogen levels (0, 250, and 350 mg/kg of soil on the reduction of toxicity due to the three levels of boron (0, 15, and 30 mg/kg of soil were examined in Badami-Zarandi variety of pistachio under greenhouse conditions. After 7 months from sowing the seeds, pistachio seedlings were harvested and desired traits were measured. The results showed that by increasing boron application level, boron concentration in the shoot and root of seedlings increased whereas their dry weight decreased. Using of nitrogen reduced the negative effects of boron on the dry weight and led to increase dry weight and decrease boron concentration in the shoot and root of pistachio, Badami variety. Nitrogen application at the levels of 250 and 350 mg N per kg of soil reduced boron uptake in shoots by reinforcing plant vegetative system and increasing chlorophyll content by 13.5% and 30.2%, respectively and finally led to diluted boron concentration in the plant (dilution effect and reduced the effects of boron toxicity. Hence, optimized nitrogen application is suggested as one of the management methods in controlling Boron toxicity under these conditions. Materials and Methods: A factorial experiment based on randomized complete block design with four replications was carried out. Soil sampling was done in 0-30 cm depth in a zeekzack way from a pistachio garden that located in mahmoodiye area in Rafsanjan. The soil sample was air-dried and passed through a 2mm sieve. The soil chemical and physical properties were measured. In this study, badami-zarand cultivar seed

  9. Experimental study on treatment of simulated boron containing radioactive wastewater by reverse osmosis membrane

    International Nuclear Information System (INIS)

    Wang Xiaowei; Yang Kai; Kong Jinsong

    2012-01-01

    Experiments were carried out on a pilot equipment to study the performance of treatment of simulated boron containing radioactive wastewater by reverse osmosis membrane. Results showed that the rejection efficiency of boron, simulated nuclides and salts in simulated wastewater could be enhanced by increasing the feedwater pH, improving the applied pressure or reducing the recovery ratio. By adjusting the simulated wastewater pH to 9.0, the boron concentration in permeate could be lower than 5 mg/L and two nuclides including cobalt and cesium could be removed to a satisfied extend. (authors)

  10. Modeling of boron control during power transients in a pressurized water reactor

    International Nuclear Information System (INIS)

    Mathieu, P.; Distexhe, E.

    1986-01-01

    Accurate control instructions in a reactor control aid computer are included in order to realize the boron makeup throughput, which is required to obtain the boron concentration in the primary coolant loop, predicted by a neutronic code. A modeling of the transfer function between the makeup and the primary loop is proposed. The chemical and volumetric control system, the pressurizer, and the primary loop are modeled as instantaneous diffusion cells. The pipes are modeled as time lag lines. The model provides the unstationary boron distributions in the different elements of the setup. A numerical code is developed to calculate the time evolutions of the makeup throughput during power transients

  11. Removal of boron from aqueous solution by using neutralized red mud

    International Nuclear Information System (INIS)

    Cengeloglu, Yunus; Tor, Ali; Arslan, Gulsin; Ersoz, Mustafa; Gezgin, Sait

    2007-01-01

    The adsorptive removal of boron from aqueous solution by using the neutralized red mud was studied in batch equilibration technique. The effects of pH, adsorbent dosage, initial boron concentration and contact time on the adsorption were investigated. The experiments demonstrated that boron removal was of a little fluctuation in pH range of 2-7 and it takes 20 min to attain equilibrium. The adsorption data was analyzed using the Langmuir and the Freundlich isotherm models and it was found that the Freundlich isotherm model represented the measured sorption data well

  12. The effects of boron on improving aluminium tolerance in coriander (Coriandrum sativum L.

    Directory of Open Access Journals (Sweden)

    Zahra Rezaei

    2015-03-01

    Full Text Available In this study, the role of boron (BO33- on improving tolerance of coriander plant (Coriandrum sativum L. subjected to different concentrations of aluminum (Al3+ was evaluated. In this regard, an experiment was implemented with seven different concentrations of aluminum including: 0.25, 0.50, 1.00, 2.00, 3.00 and 4.00 mg/L Al3+ and three concentrations of boron including: 0.25, 0.5 and 0.75 mg/L BO33- with the control treatment. The experiment was concluded based on completely randomized design with three replications. Seeds of coriander were germinated in germinator and seedlings were grown in Hogland´s solution with different boron and aluminium concentrations. Results showed that different levels of Al3+, decreased dry weight, leaf area, length of shoot and root, amount of chlorophyll and aluminium, while proline concentration and Al3+accumulation increased. Nearly, in all concentrations of Al3+, plant height, dry weight and chlorophyll content promoted with increasing boron concentrations, but proline concentration was decreased. It could be concluded that application of boron along with Al3+, might have proved plant growth and neutralized effects of Al toxicity.

  13. Differentiation in boron distribution in adult male and female rats' normal brain: A BNCT approach

    Energy Technology Data Exchange (ETDEWEB)

    Goodarzi, Samereh, E-mail: samere.g@gmail.com [Department of Nuclear Engineering, Science and Research Branch, Islamic Azad University, PO Box 19395-1943, Tehran (Iran, Islamic Republic of); Pazirandeh, Ali, E-mail: paziran@yahoo.com [Department of Nuclear Engineering, Science and Research Branch, Islamic Azad University, PO Box 19395-1943, Tehran (Iran, Islamic Republic of); Jameie, Seyed Behnamedin, E-mail: behnamjameie@tums.ac.ir [Basic Science Department, Faculty of Allied Medicine, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Department of Anatomy, Faculty of Medicine, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Baghban Khojasteh, Nasrin, E-mail: khojasteh_n@yahoo.com [Department of Nuclear Engineering, Science and Research Branch, Islamic Azad University, PO Box 19395-1943, Tehran (Iran, Islamic Republic of)

    2012-06-15

    Boron distribution in adult male and female rats' normal brain after boron carrier injection (0.005 g Boric Acid+0.005 g Borax+10 ml distilled water, pH: 7.4) was studied in this research. Coronal sections of control and trial animal tissue samples were irradiated with thermal neutrons. Using alpha autoradiography, significant differences in boron concentration were seen in forebrain, midbrain and hindbrain sections of male and female animal groups with the highest value, four hours after boron compound injection. - Highlights: Black-Right-Pointing-Pointer Boron distribution in male and female rats' normal brain was studied in this research. Black-Right-Pointing-Pointer Coronal sections of animal tissue samples were irradiated with thermal neutrons. Black-Right-Pointing-Pointer Alpha and Lithium tracks were counted using alpha autoradiography. Black-Right-Pointing-Pointer Different boron concentration was seen in brain sections of male and female rats. Black-Right-Pointing-Pointer The highest boron concentration was seen in 4 h after boron compound injection.

  14. Boron removal from aqueous solutions by activated carbon impregnated with salicylic acid

    International Nuclear Information System (INIS)

    Celik, Z. Ceylan; Can, B.Z.; Kocakerim, M. Muhtar

    2008-01-01

    In this study, the removal of boric acid from aqueous solution by activated carbon impregnated with salicylic acid was studied in batch system. pH, adsorbent amount, initial boron concentration, temperature, shaking rate and salicylic acid film thickness were chosen as parameters. Boron removal efficiencies increased with increasing adsorbent amount, temperature and pH, decreasing initial boron concentration. As thickness of salicylic acid film on activated carbon becomes thin up to 0.088 nm, the efficiency increased, and then, the efficiency decreased with becoming thinner than 0.088 nm of salicylic acid film. Shaking rate was no effect on removal efficiency. In result, it was determined that the use of salicylic acid as an impregnant for activated carbon led to the increase of the amount of boron adsorbed. A lactone ring, being the most appropriate conformation, forms between boric acid and -COOH and -OH groups of salicylic acid

  15. In vitro biological efficacy of boronated low density lipoproteins for NCT

    International Nuclear Information System (INIS)

    Kahl, S.B.; Pate, D.; Laster, B.H.; Popenoe, E.A.; Fairchild, R.G.

    1992-01-01

    Low Density Lipoproteins (LDLs) are known to be internalized within the cell by receptor-mediated mechanisms. There is evidence that LDLs may be taken up avidly by tumor cells to provide cholesterol for the synthesis of cell membrane. Thus, the possibility exists that LDLs may provide an ideal vehicle for the transport of boron to tumor cells for Neutron Capture Therapy (NCT). A boronated analog of LDL has recently been synthesized for possible application in NCT. The analog was tested in cell culture for uptake and biological efficacy in the thermal neutron beam at the Brookhaven Medical Research Reactor (BMRR). It was found that boron concentrations ten times higher than that required for NCT were easily obtained, and that uptake data were constant with a receptor mediated binding mechanism. The measured intracellular concentration of ∼240 μg 10 B/g cells is significantly higher than that obtained with any other boron compound previously evaluated for possible clinical application

  16. Boron removal from aqueous solutions by activated carbon impregnated with salicylic acid

    Energy Technology Data Exchange (ETDEWEB)

    Celik, Z. Ceylan [Department of Environmental Engineering, Atatuerk University, Faculty of Engineering, Erzurum (Turkey)], E-mail: zcelik@atauni.edu.tr; Can, B.Z. [Department of Environmental Engineering, Atatuerk University, Faculty of Engineering, Erzurum (Turkey); Kocakerim, M. Muhtar [Department of Chemical Engineering, Atatuerk University, Faculty of Engineering, 25240 Erzurum (Turkey)

    2008-03-21

    In this study, the removal of boric acid from aqueous solution by activated carbon impregnated with salicylic acid was studied in batch system. pH, adsorbent amount, initial boron concentration, temperature, shaking rate and salicylic acid film thickness were chosen as parameters. Boron removal efficiencies increased with increasing adsorbent amount, temperature and pH, decreasing initial boron concentration. As thickness of salicylic acid film on activated carbon becomes thin up to 0.088 nm, the efficiency increased, and then, the efficiency decreased with becoming thinner than 0.088 nm of salicylic acid film. Shaking rate was no effect on removal efficiency. In result, it was determined that the use of salicylic acid as an impregnant for activated carbon led to the increase of the amount of boron adsorbed. A lactone ring, being the most appropriate conformation, forms between boric acid and -COOH and -OH groups of salicylic acid.

  17. 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

  18. Toxicity evaluation of boron nitride nanospheres and water-soluble boron nitride in Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    Wang N

    2017-08-01

    Full Text Available Ning Wang,1 Hui Wang,2 Chengchun Tang,3 Shijun Lei,1 Wanqing Shen,1 Cong Wang,1 Guobin Wang,4 Zheng Wang,1,4 Lin Wang1,5 1Research Center for Tissue Engineering and Regenerative Medicine, Union Hospital, 2Department of Medical Genetics, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 3Boron Nitride Research Center, School of Materials Science and Engineering, Hebei University of Technology, Tianjin, 4Department of Gastrointestinal Surgery, 5Department of Clinical Laboratory, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China Abstract: Boron nitride (BN nanomaterials have been increasingly explored for potential biological applications. However, their toxicity remains poorly understood. Using Caenorhabditis elegans as a whole-animal model for toxicity analysis of two representative types of BN nanomaterials – BN nanospheres (BNNSs and highly water-soluble BN nanomaterial (named BN-800-2 – we found that BNNSs overall toxicity was less than soluble BN-800-2 with irregular shapes. The concentration thresholds for BNNSs and BN-800-2 were 100 µg·mL-1 and 10 µg·mL-1, respectively. Above this concentration, both delayed growth, decreased life span, reduced progeny, retarded locomotion behavior, and changed the expression of phenotype-related genes to various extents. BNNSs and BN-800-2 increased oxidative stress levels in C. elegans by promoting reactive oxygen species production. Our results further showed that oxidative stress response and MAPK signaling-related genes, such as GAS1, SOD2, SOD3, MEK1, and PMK1, might be key factors for reactive oxygen species production and toxic responses to BNNSs and BN-800-2 exposure. Together, our results suggest that when concentrations are lower than 10 µg·mL-1, BNNSs are more biocompatible than BN-800-2 and are potentially biocompatible material. Keywords: boron nitride nanomaterials, Caenorhabditis elegans, nanotoxicology

  19. Android Apps for Absolute Beginners

    CERN Document Server

    Jackson, Wallace

    2011-01-01

    Anybody can start building simple apps for the Android platform, and this book will show you how! Android Apps for Absolute Beginners takes you through the process of getting your first Android applications up and running using plain English and practical examples. It cuts through the fog of jargon and mystery that surrounds Android application development, and gives you simple, step-by-step instructions to get you started.* Teaches Android application development in language anyone can understand, giving you the best possible start in Android development * Provides simple, step-by-step exampl

  20. 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

  1. 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

  2. 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.

  3. 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

  4. Boron in Pariette Wetland Sediments, Aquatic Vegetation & Benthic Organisms

    Science.gov (United States)

    Vasudeva, P.; Jones, C. P.; Powelson, D.; Jacobson, A. R.

    2015-12-01

    The Pariette Wetlands are comprised of 20 ponds located in Utah's Uintah Basin. Boron concentration in the Pariette Wetlands have been observed to exceed the total maximum daily limit of 750 µg L-1. Considering water flow in and out of the wetlands, boron is accumulating within the wetlands where it is sorbed to sediments and bioconcentrated by wetland plant and macro invertebrates. Since boron is an avian teratogen, an estimate of boron ingestion exposure is warranted. Samples from 3 of the 23 Pariette Wetland ponds with one pond near the inlet, one near the outlet, and one in the middle were collected. Five sampling points were designated along a 100 m transect of each pond. At each sampling point duplicate (or triplicate) samples of water, sediments, benthic organisms and wetland vegetation were collected. The sediments were collected with a KB-corer and divided at depths of 0-2 cm, 2-7 cm, and 7+ cm from the sediment surface. Sample splits were sent to the USU Bug lab for identification of invertebrate species. Whenever this transect was not intercepting vegetation, 2-3 additional sample sites were identified at the pond within stands of representative vegetation where bird nests are located. The plant parts used for boron analyses will include seeds, shoot and roots of vascular plants, as well as algae or duckweeds skimmed from the surface. Samples were processed within 2 days of collection. Water samples filtered through a 0.45 μ membrane filter were analyzed for DOC, pH and ECe. The dried and washed vegetation samples were ground and stored. The benthic organisms and macro invertebrates were netted at the water surface. The dried samples were weighed, ground and stored. Samples were weighed, oven dried and reweighed. For plant and macro-invertebrate samples, a nitric and hydrogen peroxide digestion procedure is used to dissolve environmentally available elements. The Hot Water extraction and DTPA-Sorbitol extraction were compared to estimate wetland plant

  5. 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)

  6. 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.)

  7. Absolute pitch: a case study.

    Science.gov (United States)

    Vernon, P E

    1977-11-01

    The auditory skill known as 'absolute pitch' is discussed, and it is shown that this differs greatly in accuracy of identification or reproduction of musical tones from ordinary discrimination of 'tonal height' which is to some extent trainable. The present writer possessed absolute pitch for almost any tone or chord over the normal musical range, from about the age of 17 to 52. He then started to hear all music one semitone too high, and now at the age of 71 it is heard a full tone above the true pitch. Tests were carried out under controlled conditions, in which 68 to 95 per cent of notes were identified as one semitone or one tone higher than they should be. Changes with ageing seem more likely to occur in the elasticity of the basilar membrane mechanisms than in the long-term memory which is used for aural analysis of complex sounds. Thus this experience supports the view that some resolution of complex sounds takes place at the peripheral sense organ, and this provides information which can be incorrect, for interpretation by the cortical centres.

  8. Absolute measurement of 152Eu

    International Nuclear Information System (INIS)

    Baba, Hiroshi; Baba, Sumiko; Ichikawa, Shinichi; Sekine, Toshiaki; Ishikawa, Isamu

    1981-08-01

    A new method of the absolute measurement for 152 Eu was established based on the 4πβ-γ spectroscopic anti-coincidence method. It is a coincidence counting method consisting of a 4πβ-counter and a Ge(Li) γ-ray detector, in which the effective counting efficiencies of the 4πβ-counter for β-rays, conversion electrons, and Auger electrons were obtained by taking the intensity ratios for certain γ-rays between the single spectrum and the spectrum coincident with the pulses from the 4πβ-counter. First, in order to verify the method, three different methods of the absolute measurement were performed with a prepared 60 Co source to find excellent agreement among the results deduced by them. Next, the 4πβ-γ spectroscopic coincidence measurement was applied to 152 Eu sources prepared by irradiating an enriched 151 Eu target in a reactor. The result was compared with that obtained by the γ-ray spectrometry using a 152 Eu standard source supplied by LMRI. They agreed with each other within the error of 2%. (author)

  9. Optimal timing of neutron irradiation for boron neutron capture therapy after intravenous infusion of sodium borocaptate in patients with glioblastoma

    International Nuclear Information System (INIS)

    Kageji, Teruyoshi; Nagahiro, Shinji; Kitamura, Katsushi; Nakagawa, Yoshinobu; Hatanaka, Hiroshi; Haritz, Dietrich; Grochulla, Frank; Haselsberger, Klaus; Gabel, Detlef

    2001-01-01

    Purpose: A cooperative study in Europe and Japan was conducted to determine the pharmacokinetics and boron uptake of sodium borocaptate (BSH: Na 2 B 12 H 11 SH), which has been introduced clinically as a boron carrier for boron neutron capture therapy in patients with glioblastoma. Methods and Materials: Data from 56 patients with glioblastoma who received BSH intravenous infusion were retrospectively reviewed. The pharmacokinetics were evaluated in 50 patients, and boron uptake was investigated in 47 patients. Patients received BSH doses between 12 and 100 mg/kg of body weight. For the evaluation, the infused boron dose was scaled linearly to 100 mg/kg BSH. Results: In BSH pharmacokinetics, the average value for total body clearance, distribution volume of steady state, and mean residence time was 3.6±1.5 L/h, 223.3±160.7 L, and 68.0±52.5 h, respectively. The average values of the boron concentration in tumor adjusted to 100 mg/kg BSH, the boron concentration in blood adjusted to 100 mg/kg BSH, and the tumor/blood boron concentration ratio were 37.1±35.8 ppm, 35.2±41.8 ppm, and 1.53±1.43, respectively. A good correlation was found between the logarithmic value of T adj and the interval from BSH infusion to tumor tissue sampling. About 12-19 h after infusion, the actual values for T adj and tumor/blood boron concentration ratio were 46.2±36.0 ppm and 1.70±1.06, respectively. The dose ratio between tumor and healthy tissue peaked in the same interval. Conclusion: For boron neutron capture therapy using BSH administered by intravenous infusion, this work confirms that neutron irradiation is optimal around 12-19 h after the infusion is started

  10. Boron removal efficiency from Red Sea water using different SWRO/BWRO membranes

    KAUST Repository

    Rahmawati, Karina; Ghaffour, NorEddine; Aubry, Cyril; Amy, Gary L.

    2012-01-01

    Seawater reverse osmosis (SWRO) desalination process provides high quality of fresh water. However, due to some operational constraints mainly scaling control some trace contaminant removal, such as acceptable boron concentration, cannot be achieved in a single pass SWRO system. The objective of this study was to investigate the efficiency of five difference reverse osmosis (RO) membranes (seawater SW and brackish water BW) provided by different manufacturers for boron removal. RO experiments using pretreated real Red Sea water were conducted in parallel to compare membrane performance under the same operating conditions. As expected, results showed that boron rejection increased as the feed pH increased. This was caused by dissociation of boric acid to negatively charged borate ions and more negatively charged membrane surface at elevated pH which enhanced boron rejection. Single pass RO system, with and without elevating the pH, may not be sufficient for two reasons. First, boron concentration in permeate does not fulfill local regulations (<0.5ppm). Second, severe scaling occurs due to operation in alkaline condition, since Ca 2+ and Mg 2+ concentrations are still high to cause salts precipitation. Techno-economical study was performed to select the best configuration and membrane giving the highest performance in terms of boron and TDS rejections and energy consumption. © 2012 Elsevier B.V.

  11. Boron doped ZnO embedded into reduced graphene oxide for electrochemical supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Alver, Ü., E-mail: ualver@ktu.edu.tr [Karadeniz Technical University, Dept. of Metallurgical and Materials Engineering, 61080 Trabzon (Turkey); Tanrıverdi, A. [Kahramanmaras Sutcu Imam University, Department of Physics, 46100 Kahramanmaraş (Turkey)

    2016-08-15

    Highlights: • Boron doped ZnO particles are fabricated and embedded into reduced graphene oxide (RGO) by hydrothermal method. • RGO/ZnO:B composites are used as electrodes for supercapacitors. • Presence of boron in RGO/ZnO composites caused increasing the stability and specific capacitance of electrodes. - Abstract: In this work, reduced graphene oxide/boron doped zinc oxide (RGO/ZnO:B) composites were fabricated by a hydrothermal process and their electrochemical properties were investigated as a function of dopant concentration. First, boron doped ZnO (ZnO:B) particles was fabricated with different boron concentrations (5, 10, 15 and 20 wt%) and then ZnO:B particles were embedded into RGO sheets. The physical properties of sensitized composites were characterized by XRD and SEM. Characterization indicated that the ZnO:B particles with plate-like structure in the composite were dispersed on graphene sheets. The electrochemical properties of the RGO/ZnO:B composite were investigated through cyclic voltammetry, galvanostatic charge/discharge measurements in a 6 M KOH electrolyte. Electrochemical measurements show that the specific capacitance values of RGO/ZnO:B electrodes increase with increasing boron concentration. RGO/ZnO:B composite electrodes (20 wt% B) display the specific capacitance as high as 230.50 F/g at 5 mV/s, which is almost five times higher than that of RGO/ZnO (52.71 F/g).

  12. Boron doped ZnO embedded into reduced graphene oxide for electrochemical supercapacitors

    International Nuclear Information System (INIS)

    Alver, Ü.; Tanrıverdi, A.

    2016-01-01

    Highlights: • Boron doped ZnO particles are fabricated and embedded into reduced graphene oxide (RGO) by hydrothermal method. • RGO/ZnO:B composites are used as electrodes for supercapacitors. • Presence of boron in RGO/ZnO composites caused increasing the stability and specific capacitance of electrodes. - Abstract: In this work, reduced graphene oxide/boron doped zinc oxide (RGO/ZnO:B) composites were fabricated by a hydrothermal process and their electrochemical properties were investigated as a function of dopant concentration. First, boron doped ZnO (ZnO:B) particles was fabricated with different boron concentrations (5, 10, 15 and 20 wt%) and then ZnO:B particles were embedded into RGO sheets. The physical properties of sensitized composites were characterized by XRD and SEM. Characterization indicated that the ZnO:B particles with plate-like structure in the composite were dispersed on graphene sheets. The electrochemical properties of the RGO/ZnO:B composite were investigated through cyclic voltammetry, galvanostatic charge/discharge measurements in a 6 M KOH electrolyte. Electrochemical measurements show that the specific capacitance values of RGO/ZnO:B electrodes increase with increasing boron concentration. RGO/ZnO:B composite electrodes (20 wt% B) display the specific capacitance as high as 230.50 F/g at 5 mV/s, which is almost five times higher than that of RGO/ZnO (52.71 F/g).

  13. Neutron autoradiography imaging of selective boron uptake in human metastatic tumours

    Energy Technology Data Exchange (ETDEWEB)

    Altieri, S. [Department of Nuclear and Theoretical Physics, University of Pavia, Via Bassi 6, Pavia (Italy); National Institute of Nuclear Physics (INFN), Section of Pavia, Via Bassi 6, Pavia (Italy)], E-mail: saverio.altieri@pv.infn.it; Bortolussi, S. [Department of Nuclear and Theoretical Physics, University of Pavia, Via Bassi 6, Pavia (Italy); National Institute of Nuclear Physics (INFN), Section of Pavia, Via Bassi 6, Pavia (Italy); Bruschi, P.; Chiari, P.; Fossati, F.; Stella, S. [Department of Nuclear and Theoretical Physics, University of Pavia, Via Bassi 6, Pavia (Italy); Prati, U.; Roveda, L. [Unit of cancer surgery, Cancer Center of Excellence, Foundation T. Campanella, Catanzaro (Italy); Zonta, A.; Zonta, C.; Ferrari, C.; Clerici, A. [Department of Surgery, University of Pavia, Piazza Botta, Pavia (Italy); Nano, R. [Department of Animal Biology, University of Pavia, Piazza Botta, Pavia (Italy); Pinelli, T. [Department of Nuclear and Theoretical Physics, University of Pavia, Via Bassi 6, Pavia (Italy); National Institute of Nuclear Physics (INFN), Section of Pavia, Via Bassi 6, Pavia (Italy)

    2008-12-15

    The ability to selectively hit the tumour cells is an essential characteristic of an anti-tumour therapy. In boron neutron capture therapy (BNCT) this characteristic is based on the selective uptake of {sup 10}B in the tumour cells with respect to normal tissues. An important step in the BNCT planning is the measurement of the boron concentration in the tissue samples, both tumour and healthy. When the tumour is spread through the healthy tissue, as in the case of metastases, the knowledge of the different kinds of tissues in the sample being analysed is crucial. If the percentage of tumour and normal tissues cannot be evaluated, the obtained concentration is a mean value depending on the composition of the different samples being measured. In this case an imaging method that could give information both on the morphology and on the spatial distribution of boron concentration in the sample would be a fundamental support. In this paper, the results of the boron uptake analysis in the tumour and in the healthy samples taken from human livers after boron phenylalanine (BPA) infusion are shown; boron imaging was performed using neutron autoradiography.

  14. Boron removal efficiency from Red Sea water using different SWRO/BWRO membranes

    KAUST Repository

    Rahmawati, Karina

    2012-12-01

    Seawater reverse osmosis (SWRO) desalination process provides high quality of fresh water. However, due to some operational constraints mainly scaling control some trace contaminant removal, such as acceptable boron concentration, cannot be achieved in a single pass SWRO system. The objective of this study was to investigate the efficiency of five difference reverse osmosis (RO) membranes (seawater SW and brackish water BW) provided by different manufacturers for boron removal. RO experiments using pretreated real Red Sea water were conducted in parallel to compare membrane performance under the same operating conditions. As expected, results showed that boron rejection increased as the feed pH increased. This was caused by dissociation of boric acid to negatively charged borate ions and more negatively charged membrane surface at elevated pH which enhanced boron rejection. Single pass RO system, with and without elevating the pH, may not be sufficient for two reasons. First, boron concentration in permeate does not fulfill local regulations (<0.5ppm). Second, severe scaling occurs due to operation in alkaline condition, since Ca 2+ and Mg 2+ concentrations are still high to cause salts precipitation. Techno-economical study was performed to select the best configuration and membrane giving the highest performance in terms of boron and TDS rejections and energy consumption. © 2012 Elsevier B.V.

  15. Thermal expansion measurements on boron carbide and europium sesquioxide by laser interferometry

    International Nuclear Information System (INIS)

    Preston, S.D.

    1980-01-01

    A laser interferometer technique for measuring the absolute linear thermal expansion of small annular specimens is described. Results are presented for unirradiated boron carbide (B 4 C) and europia (Eu 2 O 3 ) up to 1000 0 C. Both compounds are neutron-absorbing materials of potential use in fast-reactor control rods and data on their thermophysical properties, in particular linear thermal expansion, are essential to the control rod designers. (author)

  16. 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 ...

  17. 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)

  18. 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 ...

  19. Response of soybean plants to phosphorus, boron and molybdenum fertilization

    International Nuclear Information System (INIS)

    Abdel-Aziz, H. A.; Aly, M. E.

    2012-12-01

    A pot experiment was carried out to study the effect of added phosphorus levels (30. 60 kg p/fed) with the addition of boron at (2, 6 ppm) and molybdenum at (5, 10.ppm) and without addition beside the control the control on growth and mineral content and root nodules in soybean plants. The results indicated that the effect of phosphorus on the formation of nodules had a clear effect when added with boron, molybdenum and when boron added at a rate of 2 ppm in the absence of phosphorus led to increase in root nodules in each of the 5, 10 ppm led to increased formation of, naldetuss in of the alluvial and calcareous soil. The molybdenum, nitrogen and phosphorus uptake increased directly proportional to the result of increased rate of addition of phosphorus and molybdenum. While the uptake born may be added with the rate of increased concentration of 2 ppm, while when added at 6 ppm led tp increased absorption of boron in the calcareous soil, but led to a decrease in the alluvial soils. (Author)

  20. Possible application of boron neutron capture therapy to canine osteosarcoma

    International Nuclear Information System (INIS)

    Takeuchi, Akira

    1985-01-01

    Possibility for successful treatment of canine osteosarcoma by boron neutron capture therapy (BNCT) was demonstrated based upon an uptake study of the boron compound and an experimental treatment by BNCT. In the up take study following intravenous administration of Na 2 B 12 H 11 SH, satisfactorily higher boron concentration with some variation between tumors is likely to be obtained 12 hours after the administration, together with significantly lower boron levels in blood and bone. Based upon these results, osteosarcoma of a mongrel dog was successfully treated by BNCT. The tumor received approximately 3800 rads with single neutron irradiation (approximately 1.4 x 10 13 n./cm 2 ) about 12 hours after intravenous infusion of Na 2 B 12 H 11 SH of 96 % enriched 10 B in the ratio of 50 mg 10 B/kg. Clinical and radiographical improvements were remarkable and no neoplastic cell was found in any part of the original neoplastic lesion and its surrounding tissue at the time of autopsy after 30 days. (author)

  1. Commercial Clinical Application of Boron Neutron Capture Therapy

    International Nuclear Information System (INIS)

    1999-01-01

    CRADA No. 95-CR-09 among the LITCO--now Bechtel BWXT Idaho, LLC; a private company, Neutron Therapies Limited Liability Company, NTL formerly Ionix Corporation; and Washington State University was established in 1996 to further the development of BNCT. NTL has established a laboratory for the synthesis, under US FDA approved current Good Manufacturing Practices (cGMP) guidelines, of key boron intermediates and final boron agents for BNCT. The company has focused initially on the development of the compound GB-10 (Na 2 B 10 H 10 ) as the first boron agent of interest. An Investigational New Drug (IND) application for GB-10 has been filed and approved by the FDA for a Phase I human biodistribution trial in patients with non-small cell lung cancer and glioblastoma multiforme at UW under the direction of Professor Keith Stelzer, Principal Investigator (PI). These trials are funded by NTL under a contract with the UW, Department of Radiation Oncology, and the initial phases are nearing completion. Initial results show that boron-10 concentrations on the order of 100 micrograms per gram (100 ppm) can be achieved and maintained in blood with no indication of toxicity

  2. 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

  3. Boron-Containing Compounds for Liposome-Mediated Tumor Localization and Application to Neutron Capture Therapy

    International Nuclear Information System (INIS)

    Hawthorne, M. Frederick

    2005-01-01

    Medical application of boron neutron capture therapy (BNCT) has been significantly hindered by the slow development of boron drug-targeting methodologies for the selective delivery of high boron concentration sto malignant cells. We have successfully sought to fill this need by creating liposomes suitable as in vivo boron delivery vehicles for BNCT. Delivery of therapeutic quantities of boron to tumors in murine models has been achieved with small unilamellar boron-rich liposomes. Subsequently, attempts have been made to improve delivery efficiency of liposomes encapsulating boron-containing water-soluble species into their hollow core by incorporating lipophilic boron compounds as addenda to the liposome bilayer, incorporating boron compounds as structural components of the bilayer (which however, poses the risk of sacrificing some stability), and combinations thereof. Regardless of the method, approximately 90% of the total liposome mass remains therapeutically inactive and comprised of the vehicle's construction materials, while less than 5% is boron for neutron targeting. Following this laboratory's intensive study, the observed tumor specificity of certain liposomes has been attributed to their diminutive size of these liposomes (30-150 nm), which enables these small vesicles to pass through the porous, immature vasculature of rapidly growing tumor tissue. We surmised that any amphiphilic nanoparticle of suitable size could possess some tumor selectivity. Consequently, the discovery of a very boron-rich nanoparticle delivery agent with biodistribution performance similar to unilamellar liposomes became one of our goals. Closomers, a new class of polyhedral borane derivatives, attracted us as an alternative BNCT drug-delivery system. We specifically envisioned dodeca (nido-carboranyl)-substituted closomers as possibly having a great potential role in BNCT drug delivery. They could function as extraordinarily boron-rich BNCT drugs since they are amphiphilic

  4. Biodistribution of a new boron compound for BNCT in an experimental model of oral cancer

    International Nuclear Information System (INIS)

    Kreimann, Erica L.; Itoiz, Maria E.; Schwint, Amanda E.; Miura, M.; Coderre, J.A.; Garavaglia, Ricardo; Batistoni, Daniel A.

    2000-01-01

    We have proposed and validated the HCP carcinogenesis model of oral cancer, a model that mimics spontaneous malignant transformation, for BNCT research in a separate study. We herein perform a biodistribution study of a lipophilic carborane-containing tetraphenylporphyrin, CuTCPH, in this model. This compound was previously tested in a model of mice bearing subcutaneously transplanted mammary carcinomas. In the present study CuTCPH was administered as a single i.p. injection at a dose of 32 μg/g b.w. (10 μg B/g b.w.) or as 4 i.p. injections over 2 days at a dose of 32 μg/g b.w. per injection. Blood (Bl) and tissue, i.e. tumor (T), precancerous tissue surrounding tumor (P), normal pouch (N), skin, tongue, cheek and palate mucosa, liver, spleen, parotid gland and brain were sampled 3, 6, 12, 24, 48 and 72 hs post-administration in the single dose protocol and 1-4 days after the last injection in the multidose protocol. Boron (B) analysis was performed by ICP-AES. The maximum ratio of B concentration for the single dose protocol was 32.7:1 for T:N and 31.8:1 for T:Bl. The B value in tumor reached a maximum of 43.8 ppm. However, the mean value of 16 ± 14.3 ppm fell short of therapeutically useful levels. The multidose protocol yielded maximum ratios of 53.33:1 for T:N and 3633.3:1 for T:Bl. The maximum absolute B value in tumor reached 106.40 ppm. The mean value in tumor 3 days post-administration was 68.02 ± 25.02. Absolute and relative maximum and average B values markedly exceeded the therapeutic threshold values. (author)

  5. 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

  6. 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.

  7. Absolute measurement of 85Sr

    International Nuclear Information System (INIS)

    Miyahara, Hiroshi; Watanabe, Tamaki

    1978-01-01

    An extension of 4πe.x-γ coincidence technique is described to measure the absolute disintegration rate of 85 Sr. This nuclide shows electron capture-gamma decay, and 514keV level of 85 Rb is a meta-stable state with half life of 0.958 μsec. Therefore, the conventional 4 πe.x-γ coincidence technique with about 1 μsec of resolution time can not be applied to this nuclide. To measure the absolute disintegration rate of this, the delayed 4 πe.x-γ coincidence technique with two different resolution time has been used. The disintegration rate was determined from four counting rates of electron-x ray, gamma ray and two coincidences, and the true disintegration rate could be obtained by extraporation of the electron-x ray detection efficiency to 1. Two resolution time appearing in the calculation formulas were determined from the chance coincidence between electron-x ray and delayed gamma ray signals. When the coincidence countings with three different resolution time were carried out by one coincidence circuit, the results calculated from all combinations did not agree each other. However, when the two coincidence circuits of the same type were used to fix the resolution time, a good coincidence absorption function was obtained and the disintegration rate was determined with accuracy of +- 0.5%. To evaluate the validity of the results the disintegration rates were measured by two NaI (Tl) scintillation detectors whose gamma-ray detection efficiency was previously determined and both results were agreed within accuracy of +- 0.5%. This method can be applied with nearly same accuracy for the beta-gamma decay nuclide possessing a meta-stable state of the half life below about 10 μsec. (auth.)

  8. Evaluation of selective boron absorption in liver tumors

    International Nuclear Information System (INIS)

    Chiaraviglio, D.; Grazia, F. De; Zonta, A.; Altieri, S.; Pedroni, P.; Braghieri, B.; Fossati, F.; Pinelli, T.; Perotti, A.; Specchiarello, S.; Perlini, G.; Rief, H.

    1988-01-01

    The first step was a pharmacokinetic study to identify substances which are good boron transporters and are therefore able to provide a high concentration of the nuclide with respect to the healthy hepatic tissue in the MHN. For this purpose the tumor M5076/73 (M5), which matastasizes spontaneously in liver, was inoculated subcutaneously in a group of C57B1/6 mice. Thirty days after the inoculation, when 90% of the liver was invaded by metastases, a boric acid 0.3 M solution enriched to 96% 10 B was injected into the caudal vein. The mice were sacrificed and the liver was frozen for measurements. Boron concentration in the various samples was achieved by measuring the energy distribution of α particles produced in the nuclear reaction 10 B(n, α) 7 Li induced by a thermal neutron beam extracted from the Triga Mark II reactor,

  9. Response of the oral mucosa to porphyrin mediated boron neutron capture therapy

    International Nuclear Information System (INIS)

    Morris, G.M.

    2003-01-01

    Pre-clinical studies are now in progress to develop boron neutron capture therapy (BNCT) modalities for the treatment of head and neck carcinomas. BNCT is a bimodal therapy which involves the administration of a boron-10 enriched compound, that accumulates preferentially in tumours, prior to irradiation with low energy neutrons. These neutrons are captured by boron-10 atoms to produce a highly localised radiation exposure. More recently, it has been demonstrated that various boronated porphyrins can target a variety of tumours. Of the porphyrins evaluated to date, copper tetracarboranylphenyl porphyrin (CuTCPH) is a strong candidate for potential clinical evaluation. It has extremely high specificity for a variety of tumour models. Therapeutic efficacy of CuTCPH mediated BNCT has been demonstrated in pre-clinical studies using the murine EMT-6 carcinoma model. In the present investigation the response of the oral mucosa to CuTCPH mediated boron neutron capture (BNC) irradiation was assessed using a standard rat model (ventral tongue). Single exposure irradiation was carried out on the thermal neutron beam at the Brookhaven Medical Research Reactor, at 3 days after the final injection of the boronated porphyrin. The impact of CuTCPH mediated BNC irradiation on oral mucosa at therapeutically effective exposure times, assessed using the ventral tongue model, was minimal. This was primarily due to the fact that blood boron levels (from CuTCPH) were very low at the time of irradiation. Analysis of the dose-effect data for CuTCPH gave a compound biological effectiveness (CBE) factor of 2.5. It can be concluded that, although, the CBE factor (calculated using blood boron concentrations) was relatively high, CuTCPH mediated BNC irradiation should not cause significant damage at clinically relevant radiation doses. This is because blood boron levels would be very low at the time of irradiation

  10. Flash lamp annealing of ion implanted boron profiles

    International Nuclear Information System (INIS)

    Wieser, E.; Syhre, H.; Ruedenauer, F.G.; Steiger, W.

    1983-05-01

    The diffusion behaviour of ion implanted boron profiles (5x10E15 B/cm 2 , 50keV) in silicon at 800 0 C and 900 0 C has been compared for samples with and without foregoing flahs - lamp annealing of the radiation damage. The observed differences are discussed with respect to mechanisms of diffusion inhibition in the high concentration region. (Author) [de

  11. The Arabidopsis-related halophyte Thellungiella halophila: boron tolerance via boron complexation with metabolites?

    Science.gov (United States)

    Lamdan, Netta Li; Attia, Ziv; Moran, Nava; Moshelion, Menachem

    2012-04-01

    Tolerance to boron (B) is still not completely understood. We tested here the hypothesis that Thellungiella halophila, an Arabidopsis thaliana-related 'extremophile' plant, with abundance of B in its natural environment, is tolerant to B, and examined the potential mechanisms of this tolerance. With 1-10 mm B applied ([B](ext)) to Thellungiella and Arabidopsis grown in hydroponics, the steady-state accumulated B concentration ([B](int)) in the root was below [B](ext), and was similar in both, suggesting both extrude B actively. Whether grown in soil or hydroponically, the shoot [B](int) was higher in Arabidopsis than in Thellungiella, suggesting more effective net B exclusion by Thellungiella root. Arabidopsis exhibited toxicity symptoms including reduced shoot fresh weight (FW), but Thellungiella was not affected, even at similar levels of shoot-accumulated [B](int) (about 10 to 40 mm B in 'shoot water'), suggesting additional B tolerance mechanism in Thellungiella shoot. At [B](ext) = 5 mm, the summed shoot concentration of the potentially B-binding polyhydroxyl metabolites (malic acid, fructose, glucose, sucrose and citric acid) in Arabidopsis was below [B](int) , but in Thellungiella it was over twofold higher than [B](int) , and therefore likely to allow appreciable 1:2 boron-metabolite complexation in the shoot. This, we suggest, is an important component of Thellungiella B tolerance mechanism. © 2011 Blackwell Publishing Ltd.

  12. Helium behaviour in implanted boron carbide

    Directory of Open Access Journals (Sweden)

    Motte Vianney

    2015-01-01

    Full Text Available When boron carbide is used as a neutron absorber in nuclear power plants, large quantities of helium are produced. To simulate the gas behaviour, helium implantations were carried out in boron carbide. The samples were then annealed up to 1500 °C in order to observe the influence of temperature and duration of annealing. The determination of the helium diffusion coefficient was carried out using the 3He(d,p4He nuclear reaction (NRA method. From the evolution of the width of implanted 3He helium profiles (fluence 1 × 1015/cm2, 3 MeV corresponding to a maximum helium concentration of about 1020/cm3 as a function of annealing temperatures, an Arrhenius diagram was plotted and an apparent diffusion coefficient was deduced (Ea = 0.52 ± 0.11 eV/atom. The dynamic of helium clusters was observed by transmission electron microscopy (TEM of samples implanted with 1.5 × 1016/cm2, 2.8 to 3 MeV 4He ions, leading to an implanted slab about 1 μm wide with a maximum helium concentration of about 1021/cm3. After annealing at 900 °C and 1100 °C, small (5–20 nm flat oriented bubbles appeared in the grain, then at the grain boundaries. At 1500 °C, due to long-range diffusion, intra-granular bubbles were no longer observed; helium segregates at the grain boundaries, either as bubbles or inducing grain boundaries opening.

  13. Nuclear-physical techniques for determination of boron distribution in pure materials

    International Nuclear Information System (INIS)

    Kadirova, M.; Jumaev, N.; Simakhin, Yu.F.; Idrisov, Kh.; Usmanova, M.M.

    2001-01-01

    To study deep boron diffusion in the complex silicon structures, consisting of interchange boron doping layers of mono- and polycrystalline silicon, separated by oxide films a technique of sidelong section by using Solid State Nuclear Track Detector (SSNTD) has been elaborated. The boron distribution determination technique is based on the detection of alpha particles from the 10B(n, )7Li reaction with cellulose nitrate film. The etched track registering cellulose nitrate film show the structure image magnified 1/sin fold. Boron concentration defined by density of the etched pits appearing on the film surface. An optical microscope analysis of the sample track-mapping image is realized by examination with closely spaced ( l < x/sin ) and largely spaced ( l x/sin ) movements. All these elaborated techniques can be used to investigate other solid matrix

  14. Boron-toxicity tolerance in barley arising from efflux transporter amplification.

    Science.gov (United States)

    Sutton, Tim; Baumann, Ute; Hayes, Julie; Collins, Nicholas C; Shi, Bu-Jun; Schnurbusch, Thorsten; Hay, Alison; Mayo, Gwenda; Pallotta, Margaret; Tester, Mark; Langridge, Peter

    2007-11-30

    Both limiting and toxic soil concentrations of the essential micronutrient boron represent major limitations to crop production worldwide. We identified Bot1, a BOR1 ortholog, as the gene responsible for the superior boron-toxicity tolerance of the Algerian barley landrace Sahara 3771 (Sahara). Bot1 was located at the tolerance locus by high-resolution mapping. Compared to intolerant genotypes, Sahara contains about four times as many Bot1 gene copies, produces substantially more Bot1 transcript, and encodes a Bot1 protein with a higher capacity to provide tolerance in yeast. Bot1 transcript levels identified in barley tissues are consistent with a role in limiting the net entry of boron into the root and in the disposal of boron from leaves via hydathode guttation.

  15. Effects of austenitization temperature on the microstructure of 15BCr30 and PL22 boron steels

    Directory of Open Access Journals (Sweden)

    C. A. Suski

    2013-01-01

    Full Text Available This paper studies boron precipitation and segregation at austenitic grain boundaries for low carbon boron steels types: PL22 and 15BCr30. The following parameters were evaluated: percentage of martensite/bainite, size and nucleation sites of austenitic grains and precipitates sizes. Three austenitization temperatures were studied (870, 1050 and 1200 °C. The highest martensite percentage occurred for 1050 °C. Iron-borocarbides were detected at grain boundaries for all tested temperatures. At 870 °C the coarse iron-borocarbides are due to non-solubility and coalescence. The highest martensite percentage at 1050 °C is caused by the discrete precipitation of iron-borocarbides at austenitic grains boundaries. The discrete precipitation was due to the low non-equilibrium segregation of boron at grain boundaries. The low non-equilibrium segregation and the small grain size at 1050 °C reduce the total boron concentration at grain boundaries.

  16. Defects in boron carbide: First-principles calculations and CALPHAD modeling

    International Nuclear Information System (INIS)

    Saengdeejing, Arkapol; Saal, James E.; Manga, Venkateswara Rao; Liu Zikui

    2012-01-01

    The energetics of defects in B 4+x C boron carbide and β-boron are studied through first-principles calculations, the supercell phonon approach and the Debye–Grüneisen model. It is found that suitable sublattice models for β-boron and B 4+x C are B 101 (B,C) 4 and B 11 (B,C) (B,C,Va) (B,Va) (B,C,Va), respectively. The thermodynamic properties of B 4+x C, β-boron, liquid and graphite are modeled using the CALPHAD approach based on the thermochemical data from first-principles calculations and experimental phase equilibrium data in the literature. The concentrations of various defects are then predicted as a function of carbon composition and temperature.

  17. Tuning the electronic properties of armchair carbon nanoribbons by a selective boron doping

    International Nuclear Information System (INIS)

    Navarro-Santos, P; Ricardo-Chavez, J L; Lopez-Sandoval, R; Reyes-Reyes, M; Rivera, J L

    2010-01-01

    Armchair carbon nanoribbons (ACNRs) substitutionally doped with boron atoms are investigated in the framework of first-principles density functional theory. Different boron-boron arrangements and concentrations are considered in order to simulate possible aggregation patterns, their structural stability and electronic behavior are determined as a function of ribbon size. In agreement with previous studies, our results show that the dopant atoms have in general a preference for edge sites, but specific effects appear as a function of concentration that importantly modify the properties of the ribbons compared to the pristine case. Interesting tendencies are discovered as a function of dopant concentration that significantly affect the electronic properties of the ribbons. We have found that BC 3 island formation and edge doping are the most important factors for the structural stabilization of the ribbons with high boron concentration (>7%) whereas for the cases of low boron concentrations ( 3 island patterns give rise to highly localized B states on top of the Fermi level, resulting in semiconducting behavior. On the other hand, when the average distance between the B atoms increases beyond island stoichiometry, the localization of their states is reduced and the ribbons may become metallic due to a band crossing caused by the lowering of the Fermi level resulting from the positive charge doping. Thus, tuning the dopant interaction would be an appropriate way to tailor the electronic properties of the ribbons in a convenient manner in view of potential technological applications.

  18. Toxicity, biodistribution, and convection-enhanced delivery of the boronated porphyrin BOPP in the 9L intracerebral rat glioma model

    International Nuclear Information System (INIS)

    Ozawa, Tomoko; Afzal, Javed; Lamborn, Kathleen R.; Bollen, Andrew W.; Bauer, William F.; Koo, Myoung-Seo; Kahl, Stephen B.; Deen, Dennis F.

    2005-01-01

    Purpose: To investigate the toxicity, biodistribution, and convection-enhanced delivery (CED) of a boronated porphyrin (BOPP) that was designed for boron neutron capture therapy and photodynamic therapy. Methods and Materials: For the toxicity study, Fischer 344 rats were injected with graded concentrations of BOPP (35-100 mg/kg) into the tail vein. For boron biodistribution studies, 9L tumor-bearing rats received BOPP either systematically (intravenously) or locally. Results: All rats that received 70 mg/kg BOPP and 70% of rats that received ≤60 mg/kg BOPP i.v. either had to be euthanized or died within 4 days of injection. In the biodistribution study, boron levels were relatively high in liver, kidney, spleen, and adrenal gland tissue, and moderate levels were found in all other organs. The maximum tumor boron concentration was 21.4 μg/g at 48 h after i.v. injection; this concentration of boron in brain tumors is at the low end of the range considered optimal for therapy. In addition, the tumor/blood ratio (approximately 1.2) was not optimal. When BOPP was delivered directly into intracerebral 9L tumors with CED, we obtained tumor boron concentrations much greater than those obtained by i.v. injection. Convection-enhanced delivery of 1.5 mg BOPP produced an average tumor boron level of 519 μg/g and a tumor/blood ratio of approximately 1850:1. Conclusions: Our study demonstrates that changing the method of BOPP delivery from i.v. to CED significantly enhances the boron concentration in tumors and produces very favorable tumor/brain and tumor/blood ratios

  19. Determination of Boron in soils and plants samples using spectrophotometric method

    International Nuclear Information System (INIS)

    Stas, J.; Hariri, Z.

    2011-10-01

    In this work, the concentration of boron in soil and plant samples was determined with UV-vis spectrophotometer by using azomethine-H as a complex reagent. The calibration curve for boron determination in the range of (0μ3 g.mL - 1) was constructed by plotting the measured absorption of the yellow azomethine-H-B complex at λmax = 412.6 nm against boron concentration in the aqueous phase. The detection limit, repeatability limit, intermediate precision, accuracy, and recovery coefficient of this method were calculated and found to be 0.021 μg.mL - 1, 0.335% , 0.81%, 2.93%, (98.4-101.5)% respectively. The influence of some foreign ions on the determination of boron were also investigated in detail, most of the studied ions, like iron, iodide, and calcium can be tolerated within the ranges of (20-35μg.mL-1), (3000-5000μg.mL - 1) , (15000-30000μg.mL - 1) respectively. This is due to the fact, that ascorbic acid and EDTA in the buffer masking reagent reaction system can be very effective in masking these ions. This method was found to be economic and suitable for boron determination in standard and local samples (soil, plant) and requires small amount of sample (1g). This method can also be applied for boron determination in water samples (drinking and industrial waste water).(author)

  20. Detection of boron in metal alloys with solid state nuclear track detector by neutron induced autoradiography

    International Nuclear Information System (INIS)

    Ali Nabipour; Hosseini, A.; Afarideh, H.

    2002-01-01

    Neutron induced autoradiography is very useful technique for detection as well as measurement of Boron densities in metal alloys. The method is relatively simple and quite sensitive in comparison with other techniques with resolution in the range of PPM. Using this technique with it is also possible to investigate microscopic scattering of Boron in metal alloys. In comparison with most techniques neutron induced autoradiography has its own difficulties and limitations. In this research measurement of Boron densities and investigation of that diffusion in metal alloys has been carried out. A flat nicely polished Boron doped metal samples is covered with a track detecting plastic (CR-39 solid state nuclear track detector) and exposed to thermal neutron dose. After irradiation the plastic detector have been removed and put in an etching solution. Since the diffusion rate of corrosive solution in those area, which heavy ions have been, produces as the result of nuclear reaction with thermal neutron are more than the other areas, some cavities are formed. The diameter of cavities or tracks cross section are increased with increasing the etching time, to some extent that it is possible to observe the cavities with optical microscopes. The density of tracks on the detector surface is directly related to the Boron concentration in the sample and thermal neutron dose. So by measuring the number of tracks on surface of the detector it would possible to calculate the concentration of Boron in metal samples. (Author)

  1. 28-Homobrassinolide mitigates boron induced toxicity through enhanced antioxidant system in Vigna radiata plants.

    Science.gov (United States)

    Yusuf, Mohammad; Fariduddin, Qazi; Ahmad, Aqil

    2011-11-01

    The objective of this study was to establish relationship between boron induced oxidative stress and antioxidant system in Vigna radiata plants and also to investigate whether brassinosteroids will enhance the level of antioxidant system that could confer tolerance to the plants from the boron induced oxidative stress. The mung bean (V. radiata cv. T-44) plants were administered with 0.50, 1.0 and 2.0 mM boron at 6 d stage for 7 d along with nutrient solution. At 13 d stage, the seedlings were sprayed with deionized water (control) or 10(-8) M of 28-homobrassinolide and plants were harvested at 21 d stage to assess growth, leaf gas-exchange traits and biochemical parameters. The boron treatments diminished growth, water relations and photosynthetic attributes along with nitrate reductase and carbonic anhydrase activity in the concentration dependent manner whereas, it enhanced lipid peroxidation, electrolyte leakage, accumulation of H(2)O(2) as well as proline, and various antioxidant enzymes in the leaves of mung bean which were more pronounced at higher concentrations of boron. However, the follow-up application of 28-homobrassinolide to the boron stressed plants improved growth, water relations and photosynthesis and further enhanced the various antioxidant enzymes viz. catalase, peroxidase and superoxide dismutase and content of proline. The elevated level of antioxidant enzymes as well as proline could have conferred tolerance to the B-stressed plants resulting in improved growth, water relations and photosynthetic attributes. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. Recombination and photosensitivity centres in boron nitride irradiated with ions

    International Nuclear Information System (INIS)

    Kabyshev, A.; Konusov, F.; Lopatin, V.

    2001-01-01

    The physical-chemical processes, taking place during the irradiation of dielectrics with ions distort the electron structure of the compounds and generate additional localise state in the forbidden zone (FZ). Consequently, the semiconductor layer with the specific surface density of σ ≥ 10 -10 S/ forms on the surface of the dielectric. In addition to his, the high concentration of the radiation-induced defects changes the optical and photoelectric properties of the materials and also the energy characteristics. Analysis of the photoelectric properties indicates that the recombination processes take part in electric transport. These processes restricted the increase of the photosensitivity and changing the kinetics of relaxation of photo conductivity (σ hv ). The practical application of the boron nitride (BN) the in the thermonuclear systems (for example, Ref. 7), stimulates research into the reasons for the deceleration of its properties under the effect of radiation of various types. The conductivity of non-irradiated boron nitride is of the electron-hole nature with a large fraction of the activation component in exchange of the charge carriers between the levels of the defects and the forbidden zones. On the basis of the correlation of the energy and kinetic parameters of luminescence and , the authors of Ref. 8 constructed a model of electron transfers accompanying the electric transport of the boron nitride. In addition to ion-thermal modification, the conductivity of boron nitride is also of the electron-hole nature and is accompanied by luminescence. Examination of the characteristics of luminescence may be useful for obtaining more information on the transport mechanism. In this work, in order to clarify the main parameters of the forbidden band, detailed investigations were carried out into the spectrum of the electronic states of radiation defects which determine the photoelectric and luminescence properties of the modified boron nitride. The

  3. SU-F-T-140: Assessment of the Proton Boron Fusion Reaction for Practical Radiation Therapy Applications Using MCNP6

    Energy Technology Data Exchange (ETDEWEB)

    Adam, D; Bednarz, B [University of Wisconsin, Madison, WI (United States)

    2016-06-15

    Purpose: The proton boron fusion reaction is a reaction that describes the creation of three alpha particles as the result of the interaction of a proton incident upon a 11B target. Theoretically, the proton boron fusion reaction is a desirable reaction for radiation therapy applications in that, with the appropriate boron delivery agent, it could potentially combine the localized dose delivery protons exhibit (Bragg peak) and the local deposition of high LET alpha particles in cancerous sites. Previous efforts have shown significant dose enhancement using the proton boron fusion reaction; the overarching purpose of this work is an attempt to validate previous Monte Carlo results of the proton boron fusion reaction. Methods: The proton boron fusion reaction, 11B(p, 3α), is investigated using MCNP6 to assess the viability for potential use in radiation therapy. Simple simulations of a proton pencil beam incident upon both a water phantom and a water phantom with an axial region containing 100ppm boron were modeled using MCNP6 in order to determine the extent of the impact boron had upon the calculated energy deposition. Results: The maximum dose increase calculated was 0.026% for the incident 250 MeV proton beam scenario. The MCNP simulations performed demonstrated that the proton boron fusion reaction rate at clinically relevant boron concentrations was too small in order to have any measurable impact on the absorbed dose. Conclusion: For all MCNP6 simulations conducted, the increase of absorbed dose of a simple water phantom due to the 11B(p, 3α) reaction was found to be inconsequential. In addition, it was determined that there are no good evaluations of the 11B(p, 3α) reaction for use in MCNPX/6 and further work should be conducted in cross section evaluations in order to definitively evaluate the feasibility of the proton boron fusion reaction for use in radiation therapy applications.

  4. 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

  5. Absolute measurement of the viscosity of classical and quantum fluids by rotating-cylinder viscometers

    International Nuclear Information System (INIS)

    Donnelly, R.J.; LaMar, M.M.

    1987-01-01

    We discuss the use of rotating-cylinder viscometers to determine absolute shear viscosities of classical fluids and of helium II in the context of past and current knowledge of the stability and flow of these fluids between concentric cylinders. We identify a problem in measuring the absolute viscosity when the inner cylinder is rotating and the outer cylinder is at rest. We conclude by discussing the design of viscometers for absolute viscosity measurements in helium I and helium II

  6. Response surface modeling of boron adsorption from aqueous solution by vermiculite using different adsorption agents: Box-Behnken experimental design.

    Science.gov (United States)

    Demirçivi, Pelin; Saygılı, Gülhayat Nasün

    2017-07-01

    In this study, a different method was applied for boron removal by using vermiculite as the adsorbent. Vermiculite, which was used in the experiments, was not modified with adsorption agents before boron adsorption using a separate process. Hexadecyltrimethylammonium bromide (HDTMA) and Gallic acid (GA) were used as adsorption agents for vermiculite by maintaining the solid/liquid ratio at 12.5 g/L. HDTMA/GA concentration, contact time, pH, initial boron concentration, inert electrolyte and temperature effects on boron adsorption were analyzed. A three-factor, three-level Box-Behnken design model combined with response surface method (RSM) was employed to examine and optimize process variables for boron adsorption from aqueous solution by vermiculite using HDTMA and GA. Solution pH (2-12), temperature (25-60 °C) and initial boron concentration (50-8,000 mg/L) were chosen as independent variables and coded x 1 , x 2 and x 3 at three levels (-1, 0 and 1). Analysis of variance was used to test the significance of variables and their interactions with 95% confidence limit (α = 0.05). According to the regression coefficients, a second-order empirical equation was evaluated between the adsorption capacity (q i ) and the coded variables tested (x i ). Optimum values of the variables were also evaluated for maximum boron adsorption by vermiculite-HDTMA (HDTMA-Verm) and vermiculite-GA (GA-Verm).

  7. Physiological and Nutritional Responses of Two Distinctive Quince (cydonia oblonga mill.) Rootstocks to Boron Toxicity

    International Nuclear Information System (INIS)

    Eraslan, F.; Kucukyumuk, Z.; Polat, M.; Yildirim, A.

    2016-01-01

    The effects of excess boron (B) on some physiological and nutritional parameters of two distinctive quince (Cydonia oblonga Mill.) rootstocks were investigated. Throughout the world, B toxicity is a widely faced problem of soil in arid and semi-arid environments. In a greenhouse study, boron was applied at the rates of 0 and 40 mg kg/sup -1/ soil to quince A and quince C rootstocks. Toxicity of B differentially affected studied parameters and rootstocks. Boron toxicity increased B concentrations of both rootstocks however the increase was more pronounced in quince A rootstock. SPAD readings, (SPAD-meter, Minolta 502 Co Ltd., Japan) as a measure of chlorophyll decreased under B toxicity. Boron toxicity increased membrane permeability and anthocyanin in both rootstocks. Al though, there is rootstocks difference, lipid peroxidation (MDA) and proline and TAA (non-enzymatic total antioxidant activity) increased in response to B toxicity. In general, quince C had lower MDA (Malondialdehyde) and TAA but lower level of proline as compared to quince A. Boron toxicity did not affect the concentrations of P, Ca, Zn and Cu however increased B and Mn concentrations. Magnesium (Mg), Mn and Fe concentrations of quince were found higher than that of quince C. Indicating a genotypic effect, quince A and quince C responded to B toxicity differentially. (author)

  8. 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.

  9. 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.

  10. Sodium borocaptate (BSH) for Boron Neutron Capture Therapy (BNCT) in the hamster cheek pouch oral cancer model: boron biodistribution at 9 post administration time-points

    International Nuclear Information System (INIS)

    Garabalino, M.A.; Heber, E.M.; Monti, Hughes A.; Molinari, A.J.; Pozzi, E.C.C.; Trivillin, V.A.; Schwint, Amanda E.

    2011-01-01

    The therapeutic success of Boron Neutron Capture Therapy (BNCT) depends centrally on boron concentration in tumor and healthy tissue. We previously demonstrated the therapeutic efficacy of boronophenylalanine (BPA) and sodium decahydrodecaborate (GB-10) as boron carriers for BNCT in the hamster cheek pouch oral cancer model. Given the clinical relevance of sodium mercaptoundecahydro-closo-dodecaborate (BSH) as a boron carrier, the aim of the present study was to expand the ongoing BSH biodistribution studies in the hamster cheek pouch oral cancer model. In particular, we studied 3 additional post-administration time-points and increased the sample size corresponding to the time-points evaluated previously, to select more accurately the post-administration time at which neutron irradiation would potentially confer the greatest therapeutic advantage. BSH was dissolved in saline solution in anaerobic conditions to avoid the formation of the dimer BSSB and its oxides which are toxic. The solution was injected intravenously at a dose of 50 mg 10 B/kg (88 mg BSH / kg). Different groups of animals were killed humanely at 7, 8, and 10 h after administration of BSH. The sample size corresponding to the time-points 3, 4, 6, 9 and 12 h was increased. Samples of blood, tumor, precancerous tissue, normal pouch tissue, cheek mucosa, parotid gland, palate, skin, tongue, spinal cord marrow, brain, liver, kidney, spleen and lung were processed for boron measurement by Optic Emission Spectroscopy (ICP-OES). Boron concentration in tumor peaked to 24-34 ppm, 3-10 h post-administration of BSH, with a spread in values that resembled that previously reported in other experimental models and human subjects. The boron concentration ratios tumor/normal pouch tissue and tumor/blood ranged from 1.3 to 1.8. No selective tumor uptake was observed at any of the time points evaluated. The times post-administration of BSH that would be therapeutically most useful would be 5, 7 and 9 h. The

  11. Absolute entropy of ions in methanol

    International Nuclear Information System (INIS)

    Abakshin, V.A.; Kobenin, V.A.; Krestov, G.A.

    1978-01-01

    By measuring the initial thermoelectromotive forces of chains with bromo-silver electrodes in tetraalkylammonium bromide solutions the absolute entropy of bromide-ion in methanol is determined in the 298.15-318.15 K range. The anti Ssub(Brsup(-))sup(0) = 9.8 entropy units value is used for calculation of the absolute partial molar entropy of alkali metal ions and halogenide ions. It has been found that, absolute entropy of Cs + =12.0 entropy units, I - =14.0 entropy units. The obtained ion absolute entropies in methanol at 298.15 K within 1-2 entropy units is in an agreement with published data

  12. Near threshold absolute TDCS: First results

    International Nuclear Information System (INIS)

    Roesel, T.; Schlemmer, P.; Roeder, J.; Frost, L.; Jung, K.; Ehrhardt, H.

    1992-01-01

    A new method, and first results for an impact energy 2 eV above the threshold of ionisation of helium, are presented for the measurement of absolute triple differential cross sections (TDCS) in a crossed beam experiment. The method is based upon measurement of beam/target overlap densities using known absolute total ionisation cross sections and of detection efficiencies using known absolute double differential cross sections (DDCS). For the present work the necessary absolute DDCS for 1 eV electrons had also to be measured. Results are presented for several different coplanar kinematics and are compared with recent DWBA calculations. (orig.)

  13. Spectrophotometric determination of microamounts of boron in water

    International Nuclear Information System (INIS)

    Weber de D'Alessio, Ana; Guido, O.O.; Bandin, N.A.

    1980-01-01

    A fast method of boron in water determination has been studied for the 0.5 .- 2 μg ml -1 concentration range. The procedure is based on the formation of a coloured complex of the tetrafluoroborate of a thionine derivate cation, its extraction by an organic solvent and the further absorptiometric measurement in such media. Methylene blue and azur C were comparatively tested as organic reagents, with 1.2-dichloroethane as the extractant. The absorbance was measured at the maximum (658 nm). The tetrafluoroboric acid formation was reached in 20 min on a water-bath kept at 60 deg C. The sensitivity with methylene blue was higher than with azur C. The molar absorptivities were 65,000 and 38,000 (l mol -1 cm -1 ) respectively. For a boron concentration of 0.1 μg ml -1 the relative standard deviation was 9% for methylene blue and 7% for azur C. The procedure is applicable to the control of boron traces in heavy water of nuclear reactors refrigerating loops. (author) [es

  14. Killing effect of carboranyl uridine on boron neutron capture reaction

    International Nuclear Information System (INIS)

    Takagaki, M.; Oda, Y.; Zhang, Z.

    1994-01-01

    This paper deals with the killing effect of carboranyl uridine (CU) on thermal neutron capture reaction in cultured glioma cell line (C6). The tumoricidal effect of CU for boron neutron capture therapy in the cultured cell system is presented. To assess the uptake of CU, the number of germ cells was determined by comparing protein concentrations of C6 cells in vitro with that of intracranially transplanted C6 tumor cells in vivo. To assess tumoricidal effects of CU, human glioma cells (T98G), containing 25 ppm natural boron of CU, were irradiated with various doses of thermal neutrons at a constant fluence rate. The uptake and killing effects of mercaptoboron and boric acid were also investigated as controls. Subcellular boron concentrations confirmed the selective affinity to the nucleic acid synthesis. CU was found to have an affinity to nucleic acid synthesis and to be accumulated into nucleus of tumor cells. The irradiation dose which yielded 37% survival rate in the case of CU and control were 3.78+12E nvt and 5.80+12E nvt, respectively. The killing effect of CU was slightly higher than that of B-SH or BA. The effective way of CU injection should be further studied to obtain the uniform CU uptake in tumor cells. (N.K.)

  15. Nuclear Physics meets Medicine and Biology: Boron Neutron Capture Therapy

    CERN Document Server

    F. Ballarini, F; S. Bortolussi, S; P. Bruschi, P; A.M. Clerici, A M; A. De Bari, A; P. Dionigi, P; C. Ferrari, C; M.A. Gadan, M A; N. Protti, N; S. Stella, S; C. Zonta, C; A. Zonta, A; S. Altieri, S

    2010-01-01

    BNCT is a tumour treatment based on thermal-neutron irradiation of tissues enriched with 10B, which according to the 10B(n, )7Li reaction produces particles with high Linear Energy Transfer and short range. Since this treatment can deliver a therapeutic tumour dose sparing normal tissues, BNCT represents an alternative for diffuse tumours and metastases, which show poor response to surgery and photontherapy. In 2001 and 2003, in Pavia BNCT was applied to an isolated liver, which was infused with boron, explanted, irradiated and re-implanted. A new project was then initiated for lung tumours, developing a protocol for Boron concentration measurements and performing organ-dose Monte Carlo calculations; in parallel, radiobiology studies are ongoing to characterize the BNCT effects down to cellular level. After a brief introduction, herein we will present the main activities ongoing in Pavia including the radiobiological ones, which are under investigation not only experimentally but also theoretically, basing on...

  16. Computer modeling the boron compound factor in normal brain tissue

    International Nuclear Information System (INIS)

    Gavin, P.R.; Huiskamp, R.; Wheeler, F.J.; Griebenow, M.L.

    1993-01-01

    The macroscopic distribution of borocaptate sodium (Na 2 B 12 H 11 SH or BSH) in normal tissues has been determined and can be accurately predicted from the blood concentration. The compound para-borono-phenylalanine (p-BPA) has also been studied in dogs and normal tissue distribution has been determined. The total physical dose required to reach a biological isoeffect appears to increase directly as the proportion of boron capture dose increases. This effect, together with knowledge of the macrodistribution, led to estimates of the influence of the microdistribution of the BSH compound. This paper reports a computer model that was used to predict the compound factor for BSH and p-BPA and, hence, the equivalent radiation in normal tissues. The compound factor would need to be calculated for other compounds with different distributions. This information is needed to design appropriate normal tissue tolerance studies for different organ systems and/or different boron compounds

  17. Synthesis and characterization of boron trifluoride (B F[sub 3]). Sintese e caracterizacao de trifluoreto de boro (BF[sub 3])

    Energy Technology Data Exchange (ETDEWEB)

    Bastos, E T.R.; Umeda, K; Echternacht, M V; Silva, E.F. da.

    1994-08-01

    High purity boron trifluoride (B F[sub 3]) has been prepared from reaction of ammonium fluorborate and boron oxide in concentrated sulfuric acid. Fluorborate was synthesized by reaction of ammonium bi fluoride and boric acid produced from enrichment plant. (author).

  18. Structure and Absolute Configuration of Jurassic Polyketide-Derived Spiroborate Pigments Obtained from Microgram Quantities.

    Science.gov (United States)

    Wolkenstein, Klaus; Sun, Han; Falk, Heinz; Griesinger, Christian

    2015-10-28

    Complete structural elucidation of natural products is often challenging due to structural complexity and limited availability. This is true for present-day secondary metabolites, but even more for exceptionally preserved secondary metabolites of ancient organisms that potentially provide insights into the evolutionary history of natural products. Here, we report the full structure and absolute configuration of the borolithochromes, enigmatic boron-containing pigments from a Jurassic putative red alga, from samples of less than 50 μg using microcryoprobe NMR, circular dichroism spectroscopy, and density functional theory calculations and reveal their polyketide origin. The pigments are identified as spiroborates with two pentacyclic sec-butyl-trihydroxy-methyl-benzo[gh]tetraphen-one ligands and less-substituted derivatives. The configuration of the sec-butyl group is found to be (S). Because the exceptional benzo[gh]tetraphene scaffold is otherwise only observed in the recently discovered polyketide clostrubin from a present-day Clostridium bacterium, the Jurassic borolithochromes now can be unambiguously linked to the modern polyketide, providing evidence that the fossil pigments are almost originally preserved secondary metabolites and suggesting that the pigments in fact may have been produced by an ancient bacterium. The borolithochromes differ fundamentally from previously described boronated polyketides and represent the first boronated aromatic polyketides found so far. Our results demonstrate the potential of microcryoprobe NMR in the analysis of previously little-explored secondary metabolites from ancient organisms and reveal the evolutionary significance of clostrubin-type polyketides.

  19. Metal-insulator transition and superconductivity in heavily boron-doped diamond and related materials

    Energy Technology Data Exchange (ETDEWEB)

    Achatz, Philipp

    2009-05-15

    During this PhD project, the metal-insulator transition and superconductivity of highly boron-doped single crystal diamond and related materials have been investigated. The critical boron concentration n{sub c} for the metal-insulator transition was found to be the same as for the normal-superconductor transition. All metallic samples have been found to be superconducting and we were able to link the occurence of superconductivity to the proximity to the metal-insulator transition. For this purpose, a scaling law approach based on low temperature transport was proposed. Furthermore, we tried to study the nature of the superconductivity in highly boron doped single crystal diamond. Raman spectroscopy measurements on the isotopically substituted series suggest that the feature occuring at low wavenumbers ({approx} 500 cm{sup -1}) is the A1g vibrational mode associated with boron dimers. Usual Hall effect measurements yielded a puzzling situation in metallic boron-doped diamond samples, leading to carrier concentrations up to a factor 10 higher than the boron concentration determined by secondary ion mass spectroscopy (SIMS). The low temperature transport follows the one expected for a granular metal or insulator, depending on the interplay of intergranular and intragranular (tunneling) conductance. The metal-insulator transition takes place at a critical conductance g{sub c}. The granularity also influences significantly the superconducting properties by introducing the superconducting gap {delta} in the grain and Josephson coupling J between superconducting grains. A peak in magnetoresistance is observed which can be explained by superconducting fluctuations and the granularity of the system. Additionally we studied the low temperature transport of boron-doped Si samples grown by gas immersion laser doping, some of which yielded a superconducting transition at very low temperatures. Furthermore, preliminary results on the LO-phonon-plasmon coupling are shown for the

  20. Neutron shielding properties of boron-containing ore and epoxy composites

    International Nuclear Information System (INIS)

    Li Zhifu; Xue Xiangxin

    2011-01-01

    Using the boron-containing iron ore concentrate and boron-rich slag as studying object, the starting materials were got after the specific green ore containing boron dressing in China and blast furnace separation respectively. Monte-Carlo method was used to study the effect of the boron-containing iron ore concentrate and boron-rich slag and their composites with epoxy on the neutron shielding abilities. The reasons that affecting the shielding materials properties was discussed and the suitable proportioning of boron-containing ore to epoxy composites was confirmed; the 14.1 MeV fast neutron removal cross section and the total thermal neutron attenuation coefficient were obtained and compared with that of the common used concrete. The results show that the shielding property of 14.1 MeV fast neutron is mainly concerned with the low-Z elements in the shielding materials, the thermal neutron shielding ability is mainly concerned with boron concentrate in the composite, the attenuation of the accompany γ-ray photon is mainly concerned with the high atom number elements content in the ore and the density of the shielding material. The optimum Janume fractions of composites are in the range of 0.4-0.6 and the fast neutron shielding properties are similar to concrete while the thermal neutron shielding properties are higher than concrete. The composites are expected to be used as biological concrete shields crack injection and filling of the anomalous holes through the concrete shields around the radiation fields or directly to be prepared as shielding materials.(authors)

  1. Metal-insulator transition and superconductivity in heavily boron-doped diamond and related materials

    International Nuclear Information System (INIS)

    Achatz, Philipp

    2009-01-01

    During this PhD project, the metal-insulator transition and superconductivity of highly boron-doped single crystal diamond and related materials have been investigated. The critical boron concentration n c for the metal-insulator transition was found to be the same as for the normal-superconductor transition. All metallic samples have been found to be superconducting and we were able to link the occurence of superconductivity to the proximity to the metal-insulator transition. For this purpose, a scaling law approach based on low temperature transport was proposed. Furthermore, we tried to study the nature of the superconductivity in highly boron doped single crystal diamond. Raman spectroscopy measurements on the isotopically substituted series suggest that the feature occuring at low wavenumbers (∼ 500 cm -1 ) is the A1g vibrational mode associated with boron dimers. Usual Hall effect measurements yielded a puzzling situation in metallic boron-doped diamond samples, leading to carrier concentrations up to a factor 10 higher than the boron concentration determined by secondary ion mass spectroscopy (SIMS). The low temperature transport follows the one expected for a granular metal or insulator, depending on the interplay of intergranular and intragranular (tunneling) conductance. The metal-insulator transition takes place at a critical conductance g c . The granularity also influences significantly the superconducting properties by introducing the superconducting gap Δ in the grain and Josephson coupling J between superconducting grains. A peak in magnetoresistance is observed which can be explained by superconducting fluctuations and the granularity of the system. Additionally we studied the low temperature transport of boron-doped Si samples grown by gas immersion laser doping, some of which yielded a superconducting transition at very low temperatures. Furthermore, preliminary results on the LO-phonon-plasmon coupling are shown for the first time in aluminum

  2. Molecular basis of adaptation to high soil boron in wheat landraces and elite cultivars.

    Science.gov (United States)

    Pallotta, Margaret; Schnurbusch, Thorsten; Hayes, Julie; Hay, Alison; Baumann, Ute; Paull, Jeff; Langridge, Peter; Sutton, Tim

    2014-10-02

    Environmental constraints severely restrict crop yields in most production environments, and expanding the use of variation will underpin future progress in breeding. In semi-arid environments boron toxicity constrains productivity, and genetic improvement is the only effective strategy for addressing the problem. Wheat breeders have sought and used available genetic diversity from landraces to maintain yield in these environments; however, the identity of the genes at the major tolerance loci was unknown. Here we describe the identification of near-identical, root-specific boron transporter genes underlying the two major-effect quantitative trait loci for boron tolerance in wheat, Bo1 and Bo4 (ref. 2). We show that tolerance to a high concentration of boron is associated with multiple genomic changes including tetraploid introgression, dispersed gene duplication, and variation in gene structure and transcript level. An allelic series was identified from a panel of bread and durum wheat cultivars and landraces originating from diverse agronomic zones. Our results demonstrate that, during selection, breeders have matched functionally different boron tolerance alleles to specific environments. The characterization of boron tolerance in wheat illustrates the power of the new wheat genomic resources to define key adaptive processes that have underpinned crop improvement.

  3. 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.

  4. Removal of boron(III) by N-methylglucamine-type cellulose derivatives with higher adsorption rate

    International Nuclear Information System (INIS)

    Inukai, Yoshinari; Tanaka, Yoshiharu; Matsuda, Toshio; Mihara, Nobutake; Yamada, Kouji; Nambu, Nobuyoshi; Itoh, Osamu; Doi, Takao; Kaida, Yasuhiko; Yasuda, Seiji

    2004-01-01

    To obtain adsorbents for boron(III) derived from a natural polymer, two forms (powder and fiber) of N-methylglucamine-type cellulose derivatives were newly synthesized. After the graft polymerization of two forms of cellulose with vinyl monomer having epoxy groups, the N-methylglucamine-type cellulose derivatives were obtained by the reaction of the grafted cellulose with N-methylglucamine. The adsorption capacities of the cellulose derivatives for boron(III) were the same levels as that of a commercially available N-methylglucamine-type polystyrene resin. However, the cellulose derivatives adsorbed boron(III) more quickly than the polystyrene resin. The adsorption and desorption of boron(III) with a column method using the cellulose fiber were achieved at a higher flow rate than that using the polystyrene resin. In addition, the boron(III), adsorbed on the cellulose fiber column, was quantitatively recovered with dilute hydrochloric acid in 20- and 200-fold increased concentrations. Consequently, it was found that the cellulose derivatives were superior to the polystyrene resin as adsorbents for boron(III) for treatment of a large quantity of wastewater

  5. 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)

  6. [Effect of drinking boron on microtructure of adrenal gland in rats].

    Science.gov (United States)

    Li, Shenghe; Wang, Jue; Zhou, Jinxing; Jin, Guangming; Gu, Youfang; Xu, Wanxiang

    2012-09-01

    The effects of drinking boron exposure on the mass, organ indexes and structure of adrenal gland were studied in the paper. Methods 192 Sprague-Dawley rats (28 +/- 2 days) with no bacteria infecting were divided into six groups (n = 32, male = female) randomly. Treated rats drunk the distilled water which supplemented with boron of 0, 40, 80, 160, 320 and 640 mg/L, respectively, for 60 days. At the 30th and the 60th day of experiment, 16 rats (n = 8, male = female) of each group were selected and made into narcosis with 10% Chloral Hydrate. The adrenal glands were obtained, weighted and fixed after dissection, then the samples were made into paraffin sections, stained with HE stain and chromaffin, observed and photographed by Olympus CH-30 microphotograph system. Compared with control group, the average mass of adrenal gland of male rats in each experiment group decreased significantly or most significantly at the 30th day of experiment (P boron at 60th day of experiment increased significantly (P boron were better obviously than control group, and the numbers of chromaffin granules in chromaffin cell increased obviously. The histopathological changes of different degree could be observed in the group of 80 to 640 mg/L boron, and they became remarkable with the boron supplementation. By comparative observation, the damage of cells in adrenal medulla appeared ahead of them in adrenal cortex, and the pathological change of adrenal gland in male rats were obvious than female rats. Drinking supplemented with 40 mg/L boron could prompt the structure of adrenal gland in rats, but could cause different degree damage, or even obvious toxic effect when the concentration of boron supplementation in drinking from 80 to 640 mg/L.

  7. Boron and Coumaphos Residues in Hive Materials Following Treatments for the Control of Aethina tumida Murray

    Science.gov (United States)

    Valdovinos-Flores, Cesar; Gaspar-Ramírez, Octavio; Heras–Ramírez, María Elena; Dorantes-Ugalde, José Antonio; Saldaña-Loza, Luz María

    2016-01-01

    In the search of alternatives for controlling Aethina tumida Murray, we recently proposed the BAA trap which uses boric acid and an attractant which mimics the process of fermentation caused by Kodamaea ohmeri in the hive. This yeast is excreted in the feces of A. tumida causing the fermentation of pollen and honey of infested hives and releasing compounds that function as aggregation pheromones to A. tumida. Since the boron is the toxic element in boric acid, the aim of this article is to assess the amount of boron residues in honey and beeswax from hives treated with the BAA trap. For this aim, the amount of bioaccumulated boron in products of untreated hives was first determined and then compared with the amount of boron of products from hives treated with the BAA trap in two distinct climatic and soil conditions. The study was conducted in the cities of Padilla, Tamaulipas, and Valladolid, Yucatan (Mexico) from August 2014 to March 2015. The quantity of boron in honey was significantly less in Yucatan than in Tamaulipas; this agrees with the boron deficiency among Luvisol and Leptosol soils found in Yucatan compared to the Vertisol soil found in Tamaulipas. In fact, the honey from Yucatan has lower boron levels than those reported in the literature. The BAA treatment was applied for four months, results show that the BAA trap does not have any residual effect in either honey or wax; i.e., there is no significant difference in boron content before and after treatment. On the other hand, the organophosphate pesticide coumaphos was found in 100% of wax samples and in 64% of honey samples collected from Yucatan. The concentration of coumaphos in honey ranges from 0.005 to 0.040 mg/kg, which are below Maximum Residue Limit (MRL) allowed in the European Union (0.1 mg/kg) but 7.14% of samples exceeded the MRL allowed in Canada (0.02 mg/kg). PMID:27092938

  8. Boron and Coumaphos Residues in Hive Materials Following Treatments for the Control of Aethina tumida Murray.

    Directory of Open Access Journals (Sweden)

    Cesar Valdovinos-Flores

    Full Text Available In the search of alternatives for controlling Aethina tumida Murray, we recently proposed the BAA trap which uses boric acid and an attractant which mimics the process of fermentation caused by Kodamaea ohmeri in the hive. This yeast is excreted in the feces of A. tumida causing the fermentation of pollen and honey of infested hives and releasing compounds that function as aggregation pheromones to A. tumida. Since the boron is the toxic element in boric acid, the aim of this article is to assess the amount of boron residues in honey and beeswax from hives treated with the BAA trap. For this aim, the amount of bioaccumulated boron in products of untreated hives was first determined and then compared with the amount of boron of products from hives treated with the BAA trap in two distinct climatic and soil conditions. The study was conducted in the cities of Padilla, Tamaulipas, and Valladolid, Yucatan (Mexico from August 2014 to March 2015. The quantity of boron in honey was significantly less in Yucatan than in Tamaulipas; this agrees with the boron deficiency among Luvisol and Leptosol soils found in Yucatan compared to the Vertisol soil found in Tamaulipas. In fact, the honey from Yucatan has lower boron levels than those reported in the literature. The BAA treatment was applied for four months, results show that the BAA trap does not have any residual effect in either honey or wax; i.e., there is no significant difference in boron content before and after treatment. On the other hand, the organophosphate pesticide coumaphos was found in 100% of wax samples and in 64% of honey samples collected from Yucatan. The concentration of coumaphos in honey ranges from 0.005 to 0.040 mg/kg, which are below Maximum Residue Limit (MRL allowed in the European Union (0.1 mg/kg but 7.14% of samples exceeded the MRL allowed in Canada (0.02 mg/kg.

  9. Methods for separating boron from borated paraffin wax and its determination by ion chromatography

    International Nuclear Information System (INIS)

    Jeyakumar, S.

    2015-01-01

    Boron compounds are found to be useful in shielding against high-energy neutrons. In radiotherapy treatments, in order to protect occupational workers and patients from the undesirable neutron and gamma doses, paraffin wax containing B 4 C/boric acid is used. Low-level borate wastes generated from the nuclear power plants have been immobilized with paraffin wax using a concentrate waste drying system (CWDS). Borated paraffin waxes are prepared by mixing calculated amounts of either boric acid or boron carbide with the molten wax. This necessitates the determination of boron at different locations in order to check the homogeneous distribution of B over the borated wax. The determination of boron in nuclear materials is inevitable due to its high neutron absorption cross section. For the determination of boron in borated waxes, not many methods have been reported. A method based on the pyrohydrolysis extraction of boron and its quantification with ion chromatography was proposed for paraffin waxes borated with H 3 BO 3 and B 4 C. The B 4 C optimum pyrohydrolysis conditions were identified. Wax samples were mixed with U 3 O 8 , which prevents the sample from flare up, and also accelerates the extraction of boron. Pyrohydrolysis was carried out with moist O 2 at 950℃ for 60 and 90 min for wax with H 3 BO 3 and wax with B 4 C, respectively. Two simple methods of separation based on alkali extraction and melting wax in alkali were also developed exclusively for wax with H 3 BO 3 . In all the separations, the recovery of B was above 98%. During IC separation, B was separated as boron-mannitol anion complex. Linear calibration was obtained between 0.1 and 50 ppm of B, and LOD was calculated as 5 ppb (S/N=3). The reproducibility was better than 5% (RSD)

  10. Study of boron detection limit using the in-air PIGE set-up at LAMFI-USP

    Energy Technology Data Exchange (ETDEWEB)

    Moro, M. V.; Silva, T. F.; Trindade, G. F.; Added, N.; Tabacniks, M. H. [Institute of Physics, University of São Paulo, SP (Brazil)

    2014-11-11

    The quantification of small amounts of boron in materials is of extreme importance in different areas of materials science. Boron is an important contaminant and also a silicon dopant in the semiconductor industry. Boron is also extensively used in nuclear power plants, either for neutron shielding or for safety control and boron is an essential nutrient for life, either vegetable or animal. The production of silicon solar cells, by refining metallurgical-grade silicon (MG-Si) requires the control and reduction of several silicon contaminants to very low concentration levels. Boron is one of the contaminants of solar-grade silicon (SG-Si) that must be controlled and quantified at sub-ppm levels. In the metallurgical purification, boron quantification is usually made by Inductive Coupled Plasma Mass Spectrometry, (ICP-MS) but the results need to be verified by an independent analytical method. In this work we present the results of the analysis of silicon samples by Particle Induced Gamma-Ray Emission (PIGE) aiming the quantification of low concentrations of boron. PIGE analysis was carried out using the in-air external beam line of the Laboratory for Materials Analysis with Ion Beams (LAMFI-USP) by the {sup 10}B(p,αγ({sup 7}Be nuclear reaction, and measuring the 429 keV γ-ray. The in-air PIGE measurements at LAMFI have a quantification limit of the order of 10{sup 16} at/cm{sup 2}.

  11. Preparation of a radioactive boron compound (B-I-131-lipiodol) for neutron capture therapy of hepatoma

    International Nuclear Information System (INIS)

    Chou, F.I.; Chung, H.P.; Chung, R.J.; Wen, H.W.; Wei, Y.Y.; Kai, J.J.; Lui, W.Y.; Chi, C.W.

    2000-01-01

    In our research, a radioactive boron compound, B-I-131-lipiodol, that can be selectively retained in hepatoma cells was prepared. Combining the effect of α particles produced by boron neutron capture reaction with the β particles released by radionuclides in the radioactive boron compounds will produce a synergistic killing effect on cancer cells. Human hepatoma HepG2 cell cultures were used to examine the stability and the intracellular distribution of the radioactive boron drug. Microscopes were used to examine the interaction and retention of B-I-131-lipiodol globules in the individual hepatoma cell. Moreover, ICP-AES and NaI scintillation counter were performed to determine boron concentrations and I-131 radioactivity, respectively. Results showed that B-I-131-lipiodol with a boron concentration and a specific radioactivity ranged from 500-2000 ppm and 0.05-10 mCi/mL respectively was stably retained in serum. The radiochemical purity of B-I-131-lipiodol was 98%. After supplement with a medium containing B-I-131-lipiodol, the HepG2 cells had intracellular B-I-131-lipiodol globules in the cytoplasm as seen by inverted light microscope, the I-131 and boron can be stably retained in HepG2 cells. (author)

  12. Study of boron detection limit using the in-air PIGE set-up at LAMFI-USP

    Science.gov (United States)

    Moro, M. V.; Silva, T. F.; Trindade, G. F.; Added, N.; Tabacniks, M. H.

    2014-11-01

    The quantification of small amounts of boron in materials is of extreme importance in different areas of materials science. Boron is an important contaminant and also a silicon dopant in the semiconductor industry. Boron is also extensively used in nuclear power plants, either for neutron shielding or for safety control and boron is an essential nutrient for life, either vegetable or animal. The production of silicon solar cells, by refining metallurgical-grade silicon (MG-Si) requires the control and reduction of several silicon contaminants to very low concentration levels. Boron is one of the contaminants of solar-grade silicon (SG-Si) that must be controlled and quantified at sub-ppm levels. In the metallurgical purification, boron quantification is usually made by Inductive Coupled Plasma Mass Spectrometry, (ICP-MS) but the results need to be verified by an independent analytical method. In this work we present the results of the analysis of silicon samples by Particle Induced Gamma-Ray Emission (PIGE) aiming the quantification of low concentrations of boron. PIGE analysis was carried out using the in-air external beam line of the Laboratory for Materials Analysis with Ion Beans (LAMFI-USP) by the 10B ( p ,αγ(7Be nuclear reaction, and measuring the 429 keV γ-ray. The in-air PIGE measurements at LAMFI have a quantification limit of the order of 1016 at/cm2.

  13. Study of boron detection limit using the in-air PIGE set-up at LAMFI-USP

    International Nuclear Information System (INIS)

    Moro, M. V.; Silva, T. F.; Trindade, G. F.; Added, N.; Tabacniks, M. H.

    2014-01-01

    The quantification of small amounts of boron in materials is of extreme importance in different areas of materials science. Boron is an important contaminant and also a silicon dopant in the semiconductor industry. Boron is also extensively used in nuclear power plants, either for neutron shielding or for safety control and boron is an essential nutrient for life, either vegetable or animal. The production of silicon solar cells, by refining metallurgical-grade silicon (MG-Si) requires the control and reduction of several silicon contaminants to very low concentration levels. Boron is one of the contaminants of solar-grade silicon (SG-Si) that must be controlled and quantified at sub-ppm levels. In the metallurgical purification, boron quantification is usually made by Inductive Coupled Plasma Mass Spectrometry, (ICP-MS) but the results need to be verified by an independent analytical method. In this work we present the results of the analysis of silicon samples by Particle Induced Gamma-Ray Emission (PIGE) aiming the quantification of low concentrations of boron. PIGE analysis was carried out using the in-air external beam line of the Laboratory for Materials Analysis with Ion Beams (LAMFI-USP) by the 10 B(p,αγ( 7 Be nuclear reaction, and measuring the 429 keV γ-ray. The in-air PIGE measurements at LAMFI have a quantification limit of the order of 10 16 at/cm 2

  14. 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

  15. 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

  16. 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.

  17. Introducing the Mean Absolute Deviation "Effect" Size

    Science.gov (United States)

    Gorard, Stephen

    2015-01-01

    This paper revisits the use of effect sizes in the analysis of experimental and similar results, and reminds readers of the relative advantages of the mean absolute deviation as a measure of variation, as opposed to the more complex standard deviation. The mean absolute deviation is easier to use and understand, and more tolerant of extreme…

  18. Investigating Absolute Value: A Real World Application

    Science.gov (United States)

    Kidd, Margaret; Pagni, David

    2009-01-01

    Making connections between various representations is important in mathematics. In this article, the authors discuss the numeric, algebraic, and graphical representations of sums of absolute values of linear functions. The initial explanations are accessible to all students who have experience graphing and who understand that absolute value simply…

  19. 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

  20. 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

  1. 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.

  2. 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

  3. 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

  4. Particle track etch method for analysis of boron in silicon using 10B(n,α)7Li reaction

    International Nuclear Information System (INIS)

    Chakarvarti, S.K.; Nagpaul, K.K.

    1980-01-01

    Boron bulk doped p-type (111) silicon thin wafers of different resistivities (1 to 100 ohm-cm +- 20%) have been analysed for boron using cellulose nitrate-Daicel and red dyed LR-115 type II films as detectors of alpha particles from 10 B(n,α) 7 Li reaction. The two detectors measure the same value of boron (approximately 0.1 ppm) in 1 ohm-cm silicon samples and agree closely with the four-point probe electrical resistivity measurement results whereas large discrepancies are observed in case of samples with resistivity > 1 ohm-cm (B concentration 1 ohm-cm. (author)

  5. 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

  6. 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.

  7. 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

  8. 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

  9. Electrical conductivity enhancement by boron-doping in diamond using first principle calculations

    Science.gov (United States)

    Ullah, Mahtab; Ahmed, Ejaz; Hussain, Fayyaz; Rana, Anwar Manzoor; Raza, Rizwan

    2015-04-01

    Boron doping in diamond plays a vital role in enhancing electrical conductivity of diamond by making it a semiconductor, a conductor or even a superconductor. To elucidate this fact, partial and total density of states has been determined as a function of B-content in diamond. Moreover, the orbital charge distributions, B-C bond lengths and their population have been studied for B-doping in pristine diamond thin films by applying density functional theory (DFT). These parameters have been found to be influenced by the addition of different percentages of boron atoms in diamond. The electronic density of states, B-C bond situations as well as variations in electrical conductivities of diamond films with different boron content and determination of some relationship between these parameters were the basic tasks of this study. Diamond with high boron concentration (∼5.88% B-atoms) showed maximum splitting of energy bands (caused by acceptor impurity states) at the Fermi level which resulted in the enhancement of electron/ion conductivities. Because B atoms either substitute carbon atoms and/or assemble at grain boundaries (interstitial sites) inducing impurity levels close to the top of the valence band. At very high B-concentration, impurity states combine to form an impurity band which accesses the top of the valence band yielding metal like conductivity. Moreover, bond length and charge distributions are found to decrease with increase in boron percentage in diamond. It is noted that charge distribution decreased from +1.89 to -1.90 eV whereas bond length reduced by 0.04 Å with increasing boron content in diamond films. These theoretical results support our earlier experimental findings on B-doped diamond polycrystalline films which depict that the addition of boron atoms to diamond films gives a sudden fall in resistivity even up to 105 Ω cm making it a good semiconductor for its applications in electrical devices.

  10. Application of HVJ envelope system to boron neutron capture therapy (BNCT)

    International Nuclear Information System (INIS)

    Nakai, Kei; Kurooka, Masaaki; Kaneda, Yasufumi; Yamamoto, Tetsuya; Matsumura, Akira; Asano, Tomoyuki

    2006-01-01

    Boron Neutron Capture Therapy (BNCT) has been used clinically for the treatment of malignant tumors. Two drugs, p-boronophenylalanine (BPA) and sulfhydral borane (BSH), have been used as boron delivery agents. These drugs seem to be taken up preferentially in solid tumors, but it is uncertain whether therapeutic quantities of boron atoms are taken up by micro-invasive or distant tumor cells. High accumulation and high selective delivery of boron into tumor tissues are the most important requirements to achieve efficient BNCT for malignant tumor. The HVJ envelope (HVJ-E) vector system is a novel fusion-mediated gene delivery system based on inactivated hemagglutinating virus of Japan (HVJ; Sendai virus). Although we developed this vector system for gene transfer, it can also deliver proteins, synthetic oligonucleotides, and drugs. HVJ-liposome, which is liposome fused with HVJ-E, has higher boron trapping efficiency than HVJ-E alone. We report the boron delivery into cultured cells with HVJ-liposome systems. The cellular 10 B concentration after 60 min incubation with HVJ-E containing BSH was 24.9 μg/g cell pellet for BHK-21 cells (baby hamster kidney cells) and 19.4 μg/g cell pellet for SCC VII cells (murine squamous cell carcinoma). These concentrations are higher than that of 60 min incubated cells with BSH containing (100μg 10 B/ml) medium. These results indicate the HVJ-E fused with tumor cell membrane and rapidly delivered boron agents, and that the HVJ-E-mediated delivery system could be applicable to BNCT. Plans are underway to begin neutron radiation experiments in vivo and in vitro. (author)

  11. 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

  12. 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

  13. 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

  14. 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

  15. Medical aspects of boron-slow neutron capture therapy

    International Nuclear Information System (INIS)

    Sweet, W.H.

    1986-01-01

    Earlier radiations of patients with cerebral tumors disclosed the need: (1) to find a carrier of the boron compound which would leave the blood and concentrate in the tumor, (2) to use a more penetrating neutron beam, and (3) to develop a much faster method for assaying boron in blood and tissue. To some extent number1 has been accomplished in the form of Na 2 B 12 H 11 SH, number2 has yet to be achieved, and number3 has been solved by the measurement of the 478-keV gamma ray when the 10 B atom disintegrates following its capture of a slow neutron. The hitherto unreported data in this paper describe through the courtesy of Professor Hiroshi Hatanaka his studies on the pharmacokinetics and quality control of Na 2 B 12 H 11 SH based on 96 boron infusions in 86 patients. Simultaneous blood and tumor data are plotted here for 30 patients with glioblastomas (Grade III-IV gliomas), illustrating remarkable variability. Detailed autopsy findings on 18 patients with BNCT showed radiation injury in only 1. Clinical results in 12 of the most favorably situated glioblastomas reveal that 5 are still alive with a 5-year survival rate of 58% and the excellent Karnofsky performance rating of 87%. For the first time evidence is presented that slow-growing astrocytomas may benefit from BNCT. 10 references, 8 figures, 5 tables

  16. Carborane derivative development for boron neutron capture therapy. Final report

    International Nuclear Information System (INIS)

    Barnum, Beverly A.; Yan Hao; Moore, Roger; Hawthorne, M. Frederick; Baum, Kurt

    1999-01-01

    Boron Neutron Capture Therapy [BNCT] is a binary method of cancer therapy based on the capture of neutrons by a boron-10 atom [ 10 B]. Cytotoxic 7 Li nuclei and α-particles are emitted, with a range in tissue of 9 and 5 microm, respectively, about one cell diameter. The major obstacle to clinically viable BNCT is the selective localization of 5-30 ppm 10 B in tumor cells required for effective therapy. A promising approach to BNCT is based on hydrophilic boron-rich oligomeric phosphate diesters, or ''trailers'' that have been shown to concentrate selectively in tumor tissue. Examples of these compounds were prepared previously at high cost using an automated DNA synthesizer. Direct synthesis methods are needed for the production of gram-scale quantities for further biological evaluation. The work accomplished as a result of the collaboration between Fluorochem, Inc. and UCLA demonstrates that short oligomers containing at least five carborane units with four phosphodiester linkages can be prepared in substantial quantities. This work was accomplished by the application of standard phosphoramidite coupling chemistry

  17. In vitro and in vivo analysis of boronated porphyrins

    International Nuclear Information System (INIS)

    Edwards, Benjamin; Matthews, Kristin; Hou, Yongjin; Vicente, M.G.H.; Autry-Conwell, Susan; James, Boggan

    2000-01-01

    New series of meso-phenylporphyrins linked through carbon-carbon bonds to nido-carboranyl groups, and containing 26-31% boron by weight, have been reported. Dark toxicity, photo-toxicity, and measurements of uptake and efflux were performed using mouse, rat, and human malignant cell lines. Drug uptake and retention by log phase cells are shown by spectrophotometry (porphyrins) and ICP-MS (boron) of cellular extracts to be concentration and time dependent, and to be influenced by plasma lipoproteins. Plasma pharmacokinetics and tissues biodistribution were studied in adult male Fisher 344 rats with bilateral subcutaneous 9L tumors injected (2.2 ml, 2 mM i.v.) with carboranyl porphyrin solutions. Whole blood, brain, liver, spleen, skin and tumors were collected at 2, 8, 18, 24 and 48 hours post-injection. Blood cells were separated from plasma and stored frozen with the other tissues. Tissue boron content was determined quantitatively by ICP-MS analysis following microwave digestion of carefully weighed samples. (author)

  18. Boron uptake measurements in metastatic tumours in rat lung

    International Nuclear Information System (INIS)

    Bortolussi, S.; Altieri, S.; Bruschi, P.

    2006-01-01

    Lung carcinoma is the leading cause of cancer mortality worldwide; despite the introduction over the last few years of new therapeutic agents, very little progress has been made in terms of survival, and the overall prognosis for these patients remains poor. For these reasons any efforts to find and validate new effective therapeutic procedures for lung cancer are very timely and essential. To study the possibility to apply BNCT in the cure of diffuse pulmonary tumours, we created a BNCT Lung Project in Pavia, supported by Ministry of Education, University and Research (MIUR), in which Physicists, Medical Doctors and Biologists are involved. The first steps were; 1. development of an animal model for Boron uptake measurements in healthy and tumour lung tissues; 2. evaluation of the possibility to treat patients with epithermal neutron beams (See S. Altieri et al., this Conference); 3. in-vitro study of BNCT efficacy (see A. Zonta et al.). Spatial Boron distribution by neutron radiography in lung metastases from Colon Adenocarcinoma is reported; furthermore we present preliminary results of Boron concentration measures in rat lung tissues. The measures were performed using alpha spectrometry in thin tissue samples. (author)

  19. Large animal normal tissue tolerance with boron neutron capture.

    Science.gov (United States)

    Gavin, P R; Kraft, S L; DeHaan, C E; Swartz, C D; Griebenow, M L

    1994-03-30

    Normal tissue tolerance of boron neutron capture irradiation using borocaptate sodium (NA2B12H11SH) in an epithermal neutron beam was studied. Large retriever-type dogs were used and the irradiations were performed by single dose, 5 x 10 dorsal portal. Fourteen dogs were irradiated with the epithermal neutron beam alone and 35 dogs were irradiated following intravenous administration of borocaptate sodium. Total body irradiation effect could be seen from the decreased leukocytes and platelets following irradiation. Most values returned to normal within 40 days postirradiation. Severe dermal necrosis occurred in animals given 15 Gy epithermal neutrons alone and in animals irradiated to a total peak physical dose greater than 64 Gy in animals following borocaptate sodium infusion. Lethal brain necrosis was seen in animals receiving between 27 and 39 Gy. Lethal brain necrosis occurred at 22-36 weeks postirradiation. A total peak physical dose of approximately 27 Gy and blood-boron concentrations of 25-50 ppm resulted in abnormal magnetic resonance imaging results in 6 months postexamination. Seven of eight of these animals remained normal and the lesions were not detected at the 12-month postirradiation examination. The bimodal therapy presents a complex challenge in attempting to achieve dose response assays. The resultant total radiation dose is a composite of low and high LET components. The short track length of the boron fission fragments and the geometric effect of the vessels causes much of the intravascular dose to miss the presumed critical target of the endothelial cells. The results indicate a large dose-sparing effect from the boron capture reactions within the blood.

  20. Large animal normal tissue tolerance with boron neutron capture

    International Nuclear Information System (INIS)

    Gavin, P.R.; Swartz, C.D.; Kraft, S.L.; Briebenow, M.L.; DeHaan, C.E.

    1994-01-01

    Normal tissue tolerance of boron neutron capture irradiation using borocaptate sodium (NA 2 B 12 H 11 SH) in an epithermal neutron beam was studied. Large retriever-type dogs were used and the irradiations were performed by single dose, 5 x 10 dorsal portal. Fourteen dogs were irradiated with the epithermal neutron beam alone and 35 dogs were irradiated following intravenous administration of borocaptate sodium. Total body irradiation effect could be seen from the decreased leukocytes and platelets following irradiation. Most values returned to normal within 40 days postirradiation. Severe dermal necrosis occurred in animals given 15 Gy epithermal neutrons alone and in animals irradiated to a total peak physical dose greater than 64 Gy in animals following borocaptate sodium infusion. Lethal brain necrosis was seen in animals receiving between 27 and 39 Gy. Lethal brain necrosis occurred at 22-36 weeks postirradiation. A total peak physical dose of approximately 27 Gy and blood-boron concentrations of 25-50 ppm resulted in abnormal magnetic resonance imaging results in 6 months postexamination. Seven of eight of these animals remained normal and the lesions were not detected at the 12-month postirradiation examination. The bimodal therapy presents a complex challenge in attempting to achieve dose response assays. The resultant total radiation dose is a composite of low and high LET components. The short track length of the boron fission fragments and the geometric effect of the vessels causes much of the intravascular dose to miss the presumed critical target of the endothelial cells. The results indicate a large dose-sparing effect from the boron capture reactions within the blood. 23 refs., 6 figs., 2 tabs

  1. Delamination of hexagonal boron nitride in a stirred media mill

    International Nuclear Information System (INIS)

    Damm, C.; Körner, J.; Peukert, W.

    2013-01-01

    A scalable process for delamination of hexagonal boron nitride in an aqueous solution of the non-ionic surfactant TWEEN85 using a stirred media mill is presented. The size of the ZrO 2 beads used as grinding media governs the dimensions of the ground boron nitride particles as atomic force microscopic investigations (AFM) reveal: the mean flakes thickness decreases from 3.5 to 1.5 nm and the ratio between mean flake area and mean flake thickness increases from 2,200 to 5,800 nm if the grinding media size is reduced from 0.8 to 0.1 mm. This result shows that a high number of stress events in combination with low stress energy (small grinding media) facilitate delamination of the layered material whereas at high stress energies in combination with a low number of stress events (large grinding media) breakage of the layers dominates over delamination. The results of particle height analyses by AFM show that few-layer structures have been formed by stirred media milling. This result is in agreement with the layer thickness dependence of the delamination energy for hexagonal boron nitride. The concentration of nanoparticles remaining dispersed after centrifugation of the ground suspension increases with grinding time and with decreasing grinding media size. After 5 h of grinding using 0.1 mm ZrO 2 grinding media the yield of nanoparticle formation is about 5 wt%. The nanoparticles exhibit the typical Raman peak for hexagonal boron nitride at 1,366 cm −1 showing that the in-plane order in the milled platelets is remained.

  2. 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)

  3. Monte Carlo assessment of boron neutron capture therapy for the treatment of breast cancer

    Directory of Open Access Journals (Sweden)

    Mundy Daniel W.

    2005-01-01

    Full Text Available For a large number of women who are diagnosed with breast cancer every year the avail able treatment options are effective, though physically and mentally taxing. This work is a starting point of a study of the efficacy of boron neutron capture therapy as an alternative treatment for HER-2+ breast tumors. Using HER-2-specific monoclonal anti bodies coupled with a boron-rich oligomeric phosphate diester, it may be possible to deliver sufficient amounts of 10B to a tumor of the breast to al low for selective cell destruction via irradiation by thermal neutrons. A comprehensive computational model (MCNP for thermal neutron irradiation of the breast is described, as well as the results of calculations made using this model, in order to determine the optimum boron concentration within the tumor for an effective boron neutron capture therapy treatment, as compared with traditional X-ray radiotherapy. The results indicate that a boron concentration of 50-60 mg per gram of tumor tissue is optimal when considering treatment times, dose distributions and skin sparing. How ever these results are based upon best-guess assumptions that must be experimentally verified.

  4. Modeling the suppression of boron transient enhanced diffusion in silicon by substitutional carbon incorporation

    Science.gov (United States)

    Ngau, Julie L.; Griffin, Peter B.; Plummer, James D.

    2001-08-01

    Recent work has indicated that the suppression of boron transient enhanced diffusion (TED) in carbon-rich Si is caused by nonequilibrium Si point defect concentrations, specifically the undersaturation of Si self-interstitials, that result from the coupled out-diffusion of carbon interstitials via the kick-out and Frank-Turnbull reactions. This study of boron TED reduction in Si1-x-yGexCy during 750 °C inert anneals has revealed that the use of an additional reaction that further reduces the Si self-interstitial concentration is necessary to describe accurately the time evolved diffusion behavior of boron. In this article, we present a comprehensive model which includes {311} defects, boron-interstitial clusters, a carbon kick-out reaction, a carbon Frank-Turnbull reaction, and a carbon interstitial-carbon substitutional (CiCs) pairing reaction that successfully simulates carbon suppression of boron TED at 750 °C for anneal times ranging from 10 s to 60 min.

  5. Modeling the suppression of boron transient enhanced diffusion in silicon by substitutional carbon incorporation

    International Nuclear Information System (INIS)

    Ngau, Julie L.; Griffin, Peter B.; Plummer, James D.

    2001-01-01

    Recent work has indicated that the suppression of boron transient enhanced diffusion (TED) in carbon-rich Si is caused by nonequilibrium Si point defect concentrations, specifically the undersaturation of Si self-interstitials, that result from the coupled out-diffusion of carbon interstitials via the kick-out and Frank--Turnbull reactions. This study of boron TED reduction in Si 1-x-y Ge x C y during 750 o C inert anneals has revealed that the use of an additional reaction that further reduces the Si self-interstitial concentration is necessary to describe accurately the time evolved diffusion behavior of boron. In this article, we present a comprehensive model which includes {311} defects, boron-interstitial clusters, a carbon kick-out reaction, a carbon Frank--Turnbull reaction, and a carbon interstitial-carbon substitutional (C i C s ) pairing reaction that successfully simulates carbon suppression of boron TED at 750 o C for anneal times ranging from 10 s to 60 min. copyright 2001 American Institute of Physics

  6. 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)

  7. Measurement of boron and carbon fluxes in cosmic rays with the PAMELA experiment

    Energy Technology Data Exchange (ETDEWEB)

    Adriani, O.; Bongi, M. [Department of Physics and Astronomy, University of Florence, I-50019 Sesto Fiorentino, Florence (Italy); Barbarino, G. C. [Department of Physics, University of Naples " Federico II," I-80126 Naples (Italy); Bazilevskaya, G. A. [Lebedev Physical Institute, RU-119991 Moscow (Russian Federation); Bellotti, R.; Bruno, A. [Department of Physics, University of Bari, I-70126 Bari (Italy); Boezio, M.; Bonvicini, V.; Carbone, R. [INFN, Sezione di Trieste, I-34149 Trieste (Italy); Bogomolov, E. A. [Ioffe Physical Technical Institute, RU-194021 St. Petersburg (Russian Federation); Bottai, S. [INFN, Sezione di Florence, I-50019 Sesto Fiorentino, Florence (Italy); Cafagna, F. [INFN, Sezione di Bari, I-70126 Bari (Italy); Campana, D. [INFN, Sezione di Naples, I-80126 Naples (Italy); Carlson, P. [KTH, Department of Physics, and the Oskar Klein Centre for Cosmoparticle Physics, AlbaNova University Centre, SE-10691 Stockholm (Sweden); Casolino, M.; De Donato, C.; De Santis, C.; De Simone, N. [INFN, Sezione di Rome " Tor Vergata," I-00133 Rome (Italy); Castellini, G. [IFAC, I-50019 Sesto Fiorentino, Florence (Italy); Danilchenko, I. A. [National Research Nuclear University MEPhI, RU-115409 Moscow (Russian Federation); and others

    2014-08-20

    The propagation of cosmic rays inside our galaxy plays a fundamental role in shaping their injection spectra into those observed at Earth. One of the best tools to investigate this issue is the ratio of fluxes for secondary and primary species. The boron-to-carbon (B/C) ratio, in particular, is a sensitive probe to investigate propagation mechanisms. This paper presents new measurements of the absolute fluxes of boron and carbon nuclei as well as the B/C ratio from the PAMELA space experiment. The results span the range 0.44-129 GeV/n in kinetic energy for data taken in the period 2006 July to 2008 March.

  8. 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

  9. Investigations to increase the efficiency of fluorine and boron removal from groundwater using radiation-induced graft polymerization adsorbent

    International Nuclear Information System (INIS)

    Iyatomi, Yosuke; Shimada, Akiomi; Ogata, Nobuhisa; Sugihara, Kozo; Hoshina, Hiroyuki; Seko, Noriaki; Kasai, Noboru; Ueki, Yuji; Tamada, Masao

    2010-01-01

    The Japan Atomic Energy Agency is performing a research project in the Mizunami Underground Research Laboratory (MIU) to build a firm scientific and technological basis for the studies of the deep underground environment in crystalline rock. In the project, it is necessary to reduce the fluorine and boron concentrations in groundwater pumped from the MIU shafts to levels below the environmental standards. This is done at the MIU water treatment facility using coagulation and ion exchange treatment for fluorine and boron, respectively. In addition, in 2006, research started on the efficient treatment of groundwater for removal of fluorine and boron using a radiation-induced graft polymerization adsorbent. The adsorbent removed boron at a flow rate (space velocity (SV)=120 h -1 ) higher than that of a general ion exchange resin (SV=10 h -1 ) and the adsorbent could be used repeatedly. It was also apparent that the pH of groundwater had an influence on adsorption performance. With respect to fluorine removal, more than 90% of fluorine was removed. However, the adsorbent for fluorine showed a lower adsorption capacity than that for boron. The reason for this difference is considered to be related to the initial concentration difference between fluorine and boron in the groundwater. Therefore, it is necessary to define the initial concentrations of dissolved materials, which can be used as better indicators of the performance of the adsorbent. (author)

  10. The absolute environmental performance of buildings

    DEFF Research Database (Denmark)

    Brejnrod, Kathrine Nykjær; Kalbar, Pradip; Petersen, Steffen

    2017-01-01

    Our paper presents a novel approach for absolute sustainability assessment of a building's environmental performance. It is demonstrated how the absolute sustainable share of the earth carrying capacity of a specific building type can be estimated using carrying capacity based normalization factors....... A building is considered absolute sustainable if its annual environmental burden is less than its share of the earth environmental carrying capacity. Two case buildings – a standard house and an upcycled single-family house located in Denmark – were assessed according to this approach and both were found...... to exceed the target values of three (almost four) of the eleven impact categories included in the study. The worst-case excess was for the case building, representing prevalent Danish building practices, which utilized 1563% of the Climate Change carrying capacity. Four paths to reach absolute...

  11. Absolute calibration technique for spontaneous fission sources

    International Nuclear Information System (INIS)

    Zucker, M.S.; Karpf, E.

    1984-01-01

    An absolute calibration technique for a spontaneously fissioning nuclide (which involves no arbitrary parameters) allows unique determination of the detector efficiency for that nuclide, hence of the fission source strength

  12. MEAN OF MEDIAN ABSOLUTE DERIVATION TECHNIQUE MEAN ...

    African Journals Online (AJOL)

    eobe

    development of mean of median absolute derivation technique based on the based on the based on .... of noise mean to estimate the speckle noise variance. Noise mean property ..... Foraging Optimization,” International Journal of. Advanced ...

  13. Absolute spectrophotometry of Nova Cygni 1975

    International Nuclear Information System (INIS)

    Kontizas, E.; Kontizas, M.; Smyth, M.J.

    1976-01-01

    Radiometric photoelectric spectrophotometry of Nova Cygni 1975 was carried out on 1975 August 31, September 2, 3. α Lyr was used as reference star and its absolute spectral energy distribution was used to reduce the spectrophotometry of the nova to absolute units. Emission strengths of Hα, Hβ, Hγ (in W cm -2 ) were derived. The Balmer decrement Hα:Hβ:Hγ was compared with theory, and found to deviate less than had been reported for an earlier nova. (author)

  14. 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

  15. Boron Carbide: Stabilization of Highly-Loaded Aqueous Suspensions, Pressureless Sintering, and Room Temperature Injection Molding

    Science.gov (United States)

    Diaz-Cano, Andres

    Boron carbide (B4C) is the third hardest material after diamond and cubic boron nitride. It's unique combination of properties makes B4C a highly valuable material. With hardness values around 35 MPa, a high melting point, 2450°C, density of 2.52 g/cm3, and high chemical inertness, boron carbide is used in severe wear components, like cutting tools and sandblasting nozzles, nuclear reactors' control rots, and finally and most common application, armor. Production of complex-shaped ceramic component is complex and represents many challenges. Present research presents a new and novel approach to produce complex-shaped B4C components. Proposed approach allows forming to be done at room temperatures and under very low forming pressures. Additives and binder concentrations are kept as low as possible, around 5Vol%, while ceramics loadings are maximized above 50Vol%. Given that proposed approach uses water as the main solvent, pieces drying is simple and environmentally safe. Optimized formulation allows rheological properties to be tailored and adjust to multiple processing approaches, including, injection molding, casting, and additive manufacturing. Boron carbide samples then were pressureless sintered. Due to the high covalent character of boron carbide, multiples sintering aids and techniques have been proposed in order to achieve high levels of densification. However, is not possible to define a clear sintering methodology based on literature. Thus, present research developed a comprehensive study on the effect of multiple sintering aids on the densification of boron carbide when pressureless sintered. Relative densities above 90% were achieved with values above 30MPa in hardness. Current research allows extending the uses and application of boron carbide, and other ceramic systems, by providing a new approach to produce complex-shaped components with competitive properties.

  16. Stochastic approaches for time series forecasting of boron: a case study of Western Turkey.

    Science.gov (United States)

    Durdu, Omer Faruk

    2010-10-01

    In the present study, a seasonal and non-seasonal prediction of boron concentrations time series data for the period of 1996-2004 from Büyük Menderes river in western Turkey are addressed by means of linear stochastic models. The methodology presented here is to develop adequate linear stochastic models known as autoregressive integrated moving average (ARIMA) and multiplicative seasonal autoregressive integrated moving average (SARIMA) to predict boron content in the Büyük Menderes catchment. Initially, the Box-Whisker plots and Kendall's tau test are used to identify the trends during the study period. The measurements locations do not show significant overall trend in boron concentrations, though marginal increasing and decreasing trends are observed for certain periods at some locations. ARIMA modeling approach involves the following three steps: model identification, parameter estimation, and diagnostic checking. In the model identification step, considering the autocorrelation function (ACF) and partial autocorrelation function (PACF) results of boron data series, different ARIMA models are identified. The model gives the minimum Akaike information criterion (AIC) is selected as the best-fit model. The parameter estimation step indicates that the estimated model parameters are significantly different from zero. The diagnostic check step is applied to the residuals of the selected ARIMA models and the results indicate that the residuals are independent, normally distributed, and homoscadastic. For the model validation purposes, the predicted results using the best ARIMA models are compared to the observed data. The predicted data show reasonably good agreement with the actual data. The comparison of the mean and variance of 3-year (2002-2004) observed data vs predicted data from the selected best models show that the boron model from ARIMA modeling approaches could be used in a safe manner since the predicted values from these models preserve the basic

  17. 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

  18. Precision interplanar spacings measurements of boron doped silicon

    International Nuclear Information System (INIS)

    Soares, D.A.W.; Pimentel, C.A.F.

    1982-05-01

    A study of lattice parameters of boron doped silicon (10 14 -10 19 atom/cc) grown in and directions by Czochralski technique has been undertaken. Interplanar spacings (d) were measured by pseudo-Kossel technique to a precision up to 0,001%; different procedures to obtain d and the errors are discussed. It is concluded that the crystallographic planes contract preferentially and the usual study of parameter variation must be made as a function of d. The diffused B particularly contracts the [333] plane and in a more pronunciate way in high concentrations. An orientation dependence of the diffusion during growth was observed. (Author) [pt

  19. Point defects and oxidation mechanism in cubic boron nitride

    International Nuclear Information System (INIS)

    Gorshin, A.P.; Shvajko-Shvajkovskij, V.E.

    1994-01-01

    A theoretical analysis of the defect formation in boron nitride by the Schottky mechanism within the framework of the quasi-chemical approximation method is carried out. On the base of solution of the disordering equations at different conditions of electroneutrality are obtained the dependences of defect concentrations in β-BN on the partial nitrogen pressure in equilibrium conditions. Experimental checking of the theoretical analysis proposed confirms the hypothesis on the presence of defects of nonstoichiometric origin in the β-BN anion sublattice

  20. Multi-dimensional boron transport modeling in subchannel approach: Part I. Model selection, implementation and verification of COBRA-TF boron tracking model

    Energy Technology Data Exchange (ETDEWEB)

    Ozdemir, Ozkan Emre, E-mail: ozdemir@psu.edu [Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, PA 16802 (United States); Avramova, Maria N., E-mail: mna109@psu.edu [Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, PA 16802 (United States); Sato, Kenya, E-mail: kenya_sato@mhi.co.jp [Mitsubishi Heavy Industries (MHI), Kobe (Japan)

    2014-10-15

    Highlights: ► Implementation of multidimensional boron transport model in a subchannel approach. ► Studies on cross flow mechanism, heat transfer and lateral pressure drop effects. ► Verification of the implemented model via code-to-code comparison with CFD code. - Abstract: The risk of reflux condensation especially during a Small Break Loss Of Coolant Accident (SB-LOCA) and the complications of tracking the boron concentration experimentally inside the primary coolant system have stimulated and subsequently have been a focus of many computational studies on boron tracking simulations in nuclear reactors. This paper presents the development and implementation of a multidimensional boron transport model with Modified Godunov Scheme within a thermal-hydraulic code based on a subchannel approach. The cross flow mechanism in multiple-subchannel rod bundle geometry as well as the heat transfer and lateral pressure drop effects are considered in the performed studies on simulations of deboration and boration cases. The Pennsylvania State University (PSU) version of the COBRA-TF (CTF) code was chosen for the implementation of three different boron tracking models: First Order Accurate Upwind Difference Scheme, Second Order Accurate Godunov Scheme, and Modified Godunov Scheme. Based on the performed nodalization sensitivity studies, the Modified Godunov Scheme approach with a physical diffusion term was determined to provide the best solution in terms of precision and accuracy. As a part of the verification and validation activities, a code-to-code comparison was carried out with the STAR-CD computational fluid dynamics (CFD) code and presented here. The objective of this study was two-fold: (1) to verify the accuracy of the newly developed CTF boron tracking model against CFD calculations; and (2) to investigate its numerical advantages as compared to other thermal-hydraulics codes.

  1. Determination and optimization of the ζ potential in boron electrophoretic deposition on aluminium substrates

    International Nuclear Information System (INIS)

    Oliveira Sampa, M.H. de; Vinhas, L.A.; Pino, E.S.

    1991-05-01

    In this work we present an introduction of the electrophoretic process followed by a detailed experimental treatment of the technique used in the determination and optimization of the ζ-potential, mainly as a function of the electrolyte concentration, in a high purity boron electrophoretics deposition on aluminium substrates used as electrodes in neutron detectors. (author)

  2. 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

  3. 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...

  4. 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.)

  5. 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.

  6. 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.

  7. 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)

  8. 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)

  9. Sodium mercaptoundecahydro-closo-dodecaborate (BSH), a boron carrier that merits more attention

    Energy Technology Data Exchange (ETDEWEB)

    Wittig, Andrea, E-mail: wittig@med.uni-marburg.de [Department of Radiotherapy and Radiation Oncology, University Hospital Giessen and Marburg, Philipps-University Marburg, Baldingerstrasse, 35043 Marburg (Germany); Stecher-Rasmussen, Finn [NCT Physics, Nassaulaan 12, 1815 GK Alkmaar (Netherlands); Hilger, Ralf A. [Department of Medical Oncology, University Duisburg-Essen, University Hospital Essen, Hufelandstrasse 55, 45122 Essen (Germany); Rassow, Juergen [NCTeam, Department of Radiation Oncology, University Hospital Essen, University Duisburg-Essen, Hufelandstrasse 55, 45122 Essen (Germany); Mauri, Pierluigi [Consiglio Nazionale delle Ricerche, Istituto di Tecnologie, Biomediche (CNR-ITB), Via Fratelli Cervi, 93, I-20090 Segrate (Italy); Sauerwein, Wolfgang [NCTeam, Department of Radiation Oncology, University Hospital Essen, University Duisburg-Essen, Hufelandstrasse 55, 45122 Essen (Germany)

    2011-12-15

    Boron neutron capture therapy relies on the preferential delivery of a {sup 10}B-compound to tumor cells. The BSH-biodistribution was investigated in nu/nu mice and human patients. The boron concentration was measured with prompt gamma ray spectroscopy. BSH accumulates to a very low extent not only in brain, but also in fat tissue, bone and muscle, which makes BSH an interesting drug not only for brain lesions but also for tumors located at the extremities. The differential uptake in different organs indicates a complex mechanism.

  10. Boron Affects Immune Function Through Modulation of Splenic T Lymphocyte Subsets, Cytokine Secretion, and Lymphocyte Proliferation and Apoptosis in Rats.

    Science.gov (United States)

    Jin, Erhui; Li, Shenghe; Ren, Man; Hu, Qianqian; Gu, Youfang; Li, Kui

    2017-08-01

    This study demonstrated the mechanisms of boron effects in a rat model and provided a scientific basis for the rational of boron use. These findings were achieved by investigating the effects of boron (10, 20, 40, 80, 160, 320, and 640 mg/L in drinking water or 1.5, 3, 6, 12, 24, 48, and 96 mg/kg BW) on rat serum immunoglobulins (IgGs), splenic cytokines, lymphocyte subsets, as well as on lymphocyte proliferation and apoptosis. Addition of 20 (3) and 40 (6) mg/L (mg/kg BW) of boron to drinking water significantly increased rat serum IgG concentrations, splenic IFN-γ and IL-4 expression as well as the number of splenic CD3 + , CD4 + and proliferating cell nuclear antigen (PCNA) + cells. Supplementation of drinking water with 40 mg/L (6 mg/kg BW) boron also markedly increased splenic IL-2 expression and the CD4 + /CD8 + cell ratio and reduced splenic CD8 + cell number. Supplementation with 80 mg/L (12 mg/kg BW) boron significantly increased CD3 + and PCNA + cell numbers (P boron markedly reduced the serum IgG concentrations; splenic IL-2 and IL-10 expression; the number of CD3 + , CD4 + and PCNA + cells; and increased the number of splenic CD8 + and caspase-3 + cells and promoted caspase-3 expression in CD3 + cells. In conclusion, these findings suggest that the supplementation of rat drinking water with 20(3) and 40(6) mg/L (mg/kg BW) boron can markedly enhance humoral and cellular immune functions, while boron concentrations above 320 mg/L (48 mg/kg BW) can have an inhibitory effect or even toxicity on immune functions. These results exhibit a U-shaped response characteristic of low and high doses of boron supplementation on immune function and imply that proper boron supplementation in food for humans and animals could be used as an immunity regulator.

  11. A study of the distribution and uptake of boron in mango fruits using neutron-capture-radiography

    International Nuclear Information System (INIS)

    Loria, G.; Jimenez, R.; Gallardo, M.; Martini, F.; Thellier, M.

    1992-01-01

    The method of neutron-capture-radiography (NCR) was used to study the distribution of boron in mango fruit. There was a regular decrease of the concentration of natural boron from the skin (83.9 ppm, dry weight) to the interior of the fruit (2.4 ppm, dry weight, 5.6 mm deep in the fruit). When drops of a solution of ( 10 B)BO 3 H 3 were placed on the fruit surface, boron accumulated in restricted zones, within the fruit skin, which apparently corresponded to skin secretory-glands. The apparent coefficient of diffusion of boric acid from these zones of high boron accumulation to the interior of the fruit was of the order of 1.6 x 10 -12 m 2 s -1

  12. Toxicity evaluation of boron nitride nanospheres and water-soluble boron nitride in Caenorhabditis elegans.

    Science.gov (United States)

    Wang, Ning; Wang, Hui; Tang, Chengchun; Lei, Shijun; Shen, Wanqing; Wang, Cong; Wang, Guobin; Wang, Zheng; Wang, Lin

    2017-01-01

    Boron nitride (BN) nanomaterials have been increasingly explored for potential biological applications. However, their toxicity remains poorly understood. Using Caenorhabditis elegans as a whole-animal model for toxicity analysis of two representative types of BN nanomaterials - BN nanospheres (BNNSs) and highly water-soluble BN nanomaterial (named BN-800-2) - we found that BNNSs overall toxicity was less than soluble BN-800-2 with irregular shapes. The concentration thresholds for BNNSs and BN-800-2 were 100 µg·mL -1 and 10 µg·mL -1 , respectively. Above this concentration, both delayed growth, decreased life span, reduced progeny, retarded locomotion behavior, and changed the expression of phenotype-related genes to various extents. BNNSs and BN-800-2 increased oxidative stress levels in C. elegans by promoting reactive oxygen species production. Our results further showed that oxidative stress response and MAPK signaling-related genes, such as GAS1 , SOD2 , SOD3 , MEK1 , and PMK1 , might be key factors for reactive oxygen species production and toxic responses to BNNSs and BN-800-2 exposure. Together, our results suggest that when concentrations are lower than 10 µg·mL -1 , BNNSs are more biocompatible than BN-800-2 and are potentially biocompatible material.

  13. 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.

  14. 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.

  15. 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

  16. 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

  17. A new model of tail diffusion of phosphorus and boron in silicon

    International Nuclear Information System (INIS)

    Morehead, F.F.; Lever, R.F.

    1986-01-01

    It is well known that high surface concentration phosphorus diffusion leads to deeply penetrating tails in its concentration profile. At 700 0 C the tail diffusivity exceeds that of low concentration phosphorus by a factor of a thousand. Less spectacular, but very significant tailing also affects boron, making the conventional models contained in commonly available process simulation programs quite inaccurate for boron diffusions with high surface concentrations. The authors show that the observed tailing can be accounted for by a model whose central assumption is the local equality of dopant and oppositely directed defect fluxes. As predicted by the model, the effect is greatest for normal processing at low temperatures for high surface concentrations. It is minimal for the high temperatures of rapid thermal annealing and unrelated to transient effects

  18. Study of boron distribution in silicon structure by side long section technique

    International Nuclear Information System (INIS)

    Kadirova, M.; Zhumaev, N.; Simakhin, Yu.F.; Usmanova, M.M.

    1997-01-01

    To study deep boron diffusion in the complex silicon structures, consisting of interchange boron doping layers of mono- and polycrystalline silicon, separated by oxide films a technique of side long section by using Solid State Nuclear Track Detector (SSNTD) has been elaborated. The boron distribution technique is based on the detection of alpha-particles from the 10 B(n,α) 7 Li reaction with cellulose nitrate film. The etched α-track registering cellulose nitrite film show the structure image magnified 1/sinφ fold. Boron concentration defined by density of the etched pits appearing on the film surface. An optical microscope analysis of the sample track-mapping image is realised by examination with closely spaced (Δl < Δx/sinφ) and largely spaced (Δl ≥ Δx/sinφ) movements. For analysis of both experimental data the computer application programs have been developed. An universal algorithm for determination of the boron profiles has been created to take into account influence of a deeper layers on a total measurement of track density when Δl < Δx/sinφ. (author)

  19. Adsorption of sugars on Al- and Ga-doped boron nitride surfaces: A computational study

    Energy Technology Data Exchange (ETDEWEB)

    Darwish, Ahmed A. [Center for Nanotechnology, Zewail City of Science and Technology, Giza 12588 (Egypt); Department of Nuclear and Radiation Engineering, Faculty of Engineering, Alexandria University, Alexandria (Egypt); Fadlallah, Mohamed M. [Center for Fundamental Physics, Zewail City of Science and Technology, Giza 12588 (Egypt); Department of Physics, Faculty of Science, Benha University, Benha (Egypt); Badawi, Ashraf [Center for Nanotechnology, Zewail City of Science and Technology, Giza 12588 (Egypt); Maarouf, Ahmed A., E-mail: ahmed.maarouf@egnc.gov.eg [Center for Fundamental Physics, Zewail City of Science and Technology, Giza 12588 (Egypt); Egypt Nanotechnology Center & Department of Physics, Faculty of Science, Cairo University, Giza 12613 (Egypt)

    2016-07-30

    Highlights: • Doping boron nitride sheets with aluminum or gallium atoms significantly enhances their molecular adsorption properties. • Adsorption of glucose or glucosamine on Al- and Ga-doped boron nitride sheets changes the band gap. • Doping concentration changes the bad gap, but has a minor effect on the adsorption energy. - Abstract: Molecular adsorption on surfaces is a key element for many applications, including sensing and catalysis. Non-invasive sugar sensing has been an active area of research due to its importance to diabetes care. The adsorption of sugars on a template surface study is at the heart of matter. Here, we study doped hexagonal boron nitride sheets (h-BNNs) as adsorbing and sensing template for glucose and glucosamine. Using first principles calculations, we find that the adsorption of glucose and glucosamine on h-BNNs is significantly enhanced by the substitutional doping of the sheet with Al and Ga. Including long range van der Waals corrections gives adsorption energies of about 2 eV. In addition to the charge transfer occurring between glucose and the Al/Ga-doped BN sheets, the adsorption alters the size of the band gap, allowing for optical detection of adsorption. We also find that Al-doped boron nitride sheet is better than Ga-doped boron nitride sheet to enhance the adsorption energy of glucose and glucosamine. The results of our work can be potentially utilized when designing support templates for glucose and glucosamine.

  20. 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%.

  1. Study on absolute humidity influence of NRL-1 measuring apparatus for radon

    International Nuclear Information System (INIS)

    Shan Jian; Xiao Detao; Zhao Guizhi; Zhou Qingzhi; Liu Yan; Qiu Shoukang; Meng Yecheng; Xiong Xinming; Liu Xiaosong; Ma Wenrong

    2014-01-01

    The absolute humidity and temperature's effects on the NRL-1 measuring apparatus for radon were studied in this paper. By controlling the radon activity concentration of the radon laboratory in University of South China and improving the temperature and humidity adjust strategy, different correction factor values under different absolute humidities were obtained. Moreover, a correction curve between 1.90 and 14.91 g/m"3 was also attained. The results show that in the case of absolute humidity, when it is less than 2.4 g/m"3, collection efficiency of the NRL-1 measuring apparatus for radon tends to be constant, and the correction factor of the absolute humidity closes to 1. However, the correction factor increases nonlinearly along with the absolute humidity. (authors)

  2. Biological models in vivo for boron neutronic capture studies as tumors therapy

    International Nuclear Information System (INIS)

    Kreimann, Erica L.; Dagrosa, Maria A.; Schwint, Amanda E.; Itoiz, Maria E.; Pisarev, Mario A.; Farias, Silvia S.; Garavaglia, Ricardo N.; Batistoni, Daniel A.

    1999-01-01

    The use of experimental models for Boron Neutronic Capture studies as Tumors Therapy have as two main objectives: 1) To contribute to the basic knowledge of the biological mechanisms involved to increase the method therapeutical advantage, and 2) To explore the possible application of this therapeutic method to other pathologies. In this frame it was studied the carcinogenesis model of hamster cheek pouch, a type of human buccal cancer. Biodistribution studies of boron compound were performed in tumor, blood and in different precancerous and normal tissues as well as BNCT studies. Results validated this method for BNCT studies and show the capacity of the oral mucosa tumors of selectively concentrate the boron compound, showing a deleterious clear effect on the tumor after 24 hours with BNCT treatment. (author)

  3. Determination of boron in waters by using methyl borate generation and flame atomic-emission spectrometry

    International Nuclear Information System (INIS)

    Castillo, J.R.; Mir, J.M.; Martinez, C.; Bendicho, C.

    1985-01-01

    An improved method is proposed for the determination of boron in waters. The esterification reaction between boric acid and methanol in a concentrated sulphuric acid medium and the vaporisation of the methyl borate formed (boiling-point, 68 C) are used in the determination by boron by measuring the emission of the BO 2 radical at 548 nm. This reaction is carried out in a simple and inexpensive generator, designed for this purpose, and the heat developed in it causes the rapid volatilisation of the methyl borate. Thus no collection systems or carrier gas are required. The proposed method gives an improved detection limit and it can be applied to the determination of boron in water samples. It is both rapid and highly selective. (author)

  4. The irradiation behaviour of boron carbide/graphite between 800 and 1,1000C

    International Nuclear Information System (INIS)

    Hattenbach, K.; Hilgendorff, W.; Weiler, K.; Zimmermann, H.U.

    1975-01-01

    64 samples of boron carbide/graphite, a material used as burnable poison in high temperature reactors, were irradiated at temperatures between 800 and 1,100 0 C up to a fluence of 1-2 x 10 20 nvt. The following post-investigations were extended to dimensional measurements to determime a possible swelling or shrinking of the pellet, corrosion tests in completely desalinated water at 300 0 C, preparation of metallographic microsections to check for crack formation, determination of the helium hold back power and the thus involved gas chromatic analysis, as well as burn-up determinations by determining the boron 10/boron 11 ratio and the lithium concentration. (orig./LN) [de

  5. Fluoride, boron and nitrate toxicity in ground water of northwest Rajasthan, India.

    Science.gov (United States)

    Chaudhary, Veena; Kumar, Mukesh; Sharma, Mukesh; Yadav, B S

    2010-02-01

    The study was carried out to access the fluoride, boron, and nitrate concentrations in ground water samples of different villages in Indira Gandhi, Bhakra, and Gang canal catchment area of northwest Rajasthan, India. Rural population, in the study site, is using groundwater for drinking and irrigation purposes, without any quality test of water. All water samples (including canal water) were contaminated with fluoride. Fluoride, boron, and nitrate were observed in the ranges of 0.50-8.50, 0.0-7.73, and 0.0-278.68 mg/l, respectively. Most of the water samples were in the categories of fluoride 1.50 mg/l, of boron 2.0-4.0 mg/l, and of nitrate availability of these compounds in groundwater was due to natural reasons and by the use of chemical fertilizers.

  6. Boronic Acid-Based Approach for Separation and Immobilization of Glycoproteins and Its Application in Sensing

    Directory of Open Access Journals (Sweden)

    Lin Liu

    2013-10-01

    Full Text Available Glycoproteins influence a broad spectrum of biological processes including cell-cell interaction, host-pathogen interaction, or protection of proteins against proteolytic degradation. The analysis of their glyco-structures and concentration levels are increasingly important in diagnosis and proteomics. Boronic acids can covalently react with cis-diols in the oligosaccharide chains of glycoproteins to form five- or six-membered cyclic esters. Based on this interaction, boronic acid-based ligands and materials have attracted much attention in both chemistry and biology as the recognition motif for enrichment and chemo/biosensing of glycoproteins in recent years. In this work, we reviewed the progress in the separation, immobilization and detection of glycoproteins with boronic acid-functionalized materials and addressed its application in sensing.

  7. Absolute isotopic abundances of Ti in meteorites

    International Nuclear Information System (INIS)

    Niederer, F.R.; Papanastassiou, D.A.; Wasserburg, G.J.

    1985-01-01

    The absolute isotope abundance of Ti has been determined in Ca-Al-rich inclusions from the Allende and Leoville meteorites and in samples of whole meteorites. The absolute Ti isotope abundances differ by a significant mass dependent isotope fractionation transformation from the previously reported abundances, which were normalized for fractionation using 46 Ti/ 48 Ti. Therefore, the absolute compositions define distinct nucleosynthetic components from those previously identified or reflect the existence of significant mass dependent isotope fractionation in nature. We provide a general formalism for determining the possible isotope compositions of the exotic Ti from the measured composition, for different values of isotope fractionation in nature and for different mixing ratios of the exotic and normal components. The absolute Ti and Ca isotopic compositions still support the correlation of 50 Ti and 48 Ca effects in the FUN inclusions and imply contributions from neutron-rich equilibrium or quasi-equilibrium nucleosynthesis. The present identification of endemic effects at 46 Ti, for the absolute composition, implies a shortfall of an explosive-oxygen component or reflects significant isotope fractionation. Additional nucleosynthetic components are required by 47 Ti and 49 Ti effects. Components are also defined in which 48 Ti is enhanced. Results are given and discussed. (author)

  8. 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

  9. 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

  10. 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.

  11. THE EFFECT OF BORON DOSES ON PARICA (Schizolobium amazonicum Herb.

    Directory of Open Access Journals (Sweden)

    Sebastião Ferreira de Lima

    2003-07-01

    Full Text Available An experiment was conducted in a greenhouse in order to evaluate the effects of boron on parica growth and on concentration and contents of macro and micronutrients indry matter of shoots and roots. Six treatments constituted by boron doses of 0.0; 0.1; 0.3; 0.9;1.5 and 2.1 mg/dm3 in four replications were used. It was evaluated the characteristics:visual diagnostic, plants height and diameter, dry matter production of shoots and roots,concentration and contents of nutrients in dry matter of shoots and roots. The symptoms ofdeficiency can be observed in new leaves and roots and the toxicity in older leaves. Bothboron deficiency and excess inhibits plants growth, but toxicity is more damaging. The Comportamento do paricá (Schizolobium amazonicum Herb. submetido ...193approximate dose of 0 Estimate of average equilibrium moisture content of wood for 26Brazilian states, by Hailwood and Harrobin one hydrate sorption theory equation.15mg/dm3 was the best for plants growth in MSPA and MSRA. The concentration of boronincreased in MSPA and MSRA with application of increasing concentration of B, with a smallreduction in concentration of MSRA from the concentration 1.9 mg/dm3. The toxicity of boronbegins when concentration reaches 36.06 mg/dm3 in shoots and 32.38 in roots. The contentsof all nutrients, except Mn and Fe in MSPA and Cu, Fe and B in MSRA, followed its own drymatter production curves.

  12. Tuning the electronic properties of armchair carbon nanoribbons by a selective boron doping

    Energy Technology Data Exchange (ETDEWEB)

    Navarro-Santos, P; Ricardo-Chavez, J L; Lopez-Sandoval, R [Instituto Potosino de Investigacion Cientifica y Tecnologica, Camino a la presa San Jose 2055, San Luis Potosi 78216 (Mexico); Reyes-Reyes, M [Instituto de Investigacion en Comunicacion Optica, Universidad Autonoma de San Luis Potosi, Alvaro Obregon 64, San Luis Potosi 78000 (Mexico); Rivera, J L, E-mail: sandov@ipicyt.edu.m [Facultad de Ingenieria Quimica, Universidad Michoacana de San Nicolas de Hidalgo, Santiago Tapia 403, Morelia, Michoacan, 58000 (Mexico)

    2010-12-22

    Armchair carbon nanoribbons (ACNRs) substitutionally doped with boron atoms are investigated in the framework of first-principles density functional theory. Different boron-boron arrangements and concentrations are considered in order to simulate possible aggregation patterns, their structural stability and electronic behavior are determined as a function of ribbon size. In agreement with previous studies, our results show that the dopant atoms have in general a preference for edge sites, but specific effects appear as a function of concentration that importantly modify the properties of the ribbons compared to the pristine case. Interesting tendencies are discovered as a function of dopant concentration that significantly affect the electronic properties of the ribbons. We have found that BC{sub 3} island formation and edge doping are the most important factors for the structural stabilization of the ribbons with high boron concentration (>7%) whereas for the cases of low boron concentrations (<5%) the structural stabilities are similar. For all the doped cases, we have found that the BC{sub 3} island patterns give rise to highly localized B states on top of the Fermi level, resulting in semiconducting behavior. On the other hand, when the average distance between the B atoms increases beyond island stoichiometry, the localization of their states is reduced and the ribbons may become metallic due to a band crossing caused by the lowering of the Fermi level resulting from the positive charge doping. Thus, tuning the dopant interaction would be an appropriate way to tailor the electronic properties of the ribbons in a convenient manner in view of potential technological applications.

  13. 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.

  14. 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

  15. Absolute calibration in vivo measurement systems

    International Nuclear Information System (INIS)

    Kruchten, D.A.; Hickman, D.P.

    1991-02-01

    Lawrence Livermore National Laboratory (LLNL) is currently investigating a new method for obtaining absolute calibration factors for radiation measurement systems used to measure internally deposited radionuclides in vivo. Absolute calibration of in vivo measurement systems will eliminate the need to generate a series of human surrogate structures (i.e., phantoms) for calibrating in vivo measurement systems. The absolute calibration of in vivo measurement systems utilizes magnetic resonance imaging (MRI) to define physiological structure, size, and composition. The MRI image provides a digitized representation of the physiological structure, which allows for any mathematical distribution of radionuclides within the body. Using Monte Carlo transport codes, the emission spectrum from the body is predicted. The in vivo measurement equipment is calibrated using the Monte Carlo code and adjusting for the intrinsic properties of the detection system. The calibration factors are verified using measurements of existing phantoms and previously obtained measurements of human volunteers. 8 refs

  16. 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.)

  17. 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...

  18. 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)

  19. 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.)

  20. 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

  1. Oilseed rape genotypes response to boron toxicity

    Directory of Open Access Journals (Sweden)

    Savić Jasna

    2013-01-01

    Full Text Available Response of 16 oilseed rape genotypes to B (boron toxicity was analyzed by comparing the results of two experiments conducted in a glasshouse. In Experiment 1 plants were grown in standard nutrient solutions with 10 µMB (control and 1000 µM B. Relative root and shoot growth varied from 20-120% and 31-117%, respectively. Variation in B concentration in shoots was also wide (206.5-441.7 µg B g-1 DW as well as total B uptake by plant (62.3-281.2 µg B g1. Four selected genotypes were grown in Experiment 2 in pots filled with high B soil (8 kg ha-1 B; B8. Shoot growth was not affected by B8 treatment, while root and shoot B concentration was significantly increased compared to control. Genotypes Panther and Pronto which performed low relative root and shoot growth and high B accumulation in plants in Experiment 1, had good growth in B8 treatment. In Experiment 2 genotype NS-L-7 had significantly lower B concentration in shots under treatment B8, but also very high B accumulation in Experiment 1. In addition, cluster analyses classified genotypes in three groups according to traits contrasting in their significance for analyzing response to B toxicity. The first group included four varieties based on their shared characteristics that have small value for the relative growth of roots and shoots and large values of B concentration in shoot. In the second largest group were connected ten genotypes that are heterogeneous in traits and do not stand out on any characteristic. Genotypes NS-L-7 and Navajo were separated in the third group because they had big relative growth of root and shoot, but also a high concentration of B in the shoot, and high total B uptake. Results showed that none of tested genotypes could not be recommended for breeding process to tolerance for B toxicity. [Projekat Ministarstva nauke Republike Srbije, br. OI 173028

  2. Boron doped ZnO embedded into reduced graphene oxide for electrochemical supercapacitors

    Science.gov (United States)

    Alver, Ü.; Tanrıverdi, A.

    2016-08-01

    In this work, reduced graphene oxide/boron doped zinc oxide (RGO/ZnO:B) composites were fabricated by a hydrothermal process and their electrochemical properties were investigated as a function of dopant concentration. First, boron doped ZnO (ZnO:B) particles was fabricated with different boron concentrations (5, 10, 15 and 20 wt%) and then ZnO:B particles were embedded into RGO sheets. The physical properties of sensitized composites were characterized by XRD and SEM. Characterization indicated that the ZnO:B particles with plate-like structure in the composite were dispersed on graphene sheets. The electrochemical properties of the RGO/ZnO:B composite were investigated through cyclic voltammetry, galvanostatic charge/discharge measurements in a 6 M KOH electrolyte. Electrochemical measurements show that the specific capacitance values of RGO/ZnO:B electrodes increase with increasing boron concentration. RGO/ZnO:B composite electrodes (20 wt% B) display the specific capacitance as high as 230.50 F/g at 5 mV/s, which is almost five times higher than that of RGO/ZnO (52.71 F/g).

  3. Redetermination and absolute configuration of atalaphylline

    Directory of Open Access Journals (Sweden)

    Hoong-Kun Fun

    2010-02-01

    Full Text Available The title acridone alkaloid [systematic name: 1,3,5-trihydroxy-2,4-bis(3-methylbut-2-enylacridin-9(10H-one], C23H25NO4, has previously been reported as crystallizing in the chiral orthorhombic space group P212121 [Chantrapromma et al. (2010. Acta Cryst. E66, o81–o82] but the absolute configuration could not be determined from data collected with Mo radiation. The absolute configuration has now been determined by refinement of the Flack parameter with data collected using Cu radiation. All features of the molecule and its crystal packing are similar to those previously described.

  4. 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.

  5. 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

  6. 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.

  7. 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

  8. New long-cycle small modular PWR cores using particle type burnable poisons for low boron operation

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Hoseong; Hwang, Dae Hee [Department of Nuclear Engineering, Kyung Hee University, Deogyeong-daero, GiHeung-gu, Yongin, Gyeonggi-do 446-701 (Korea, Republic of); Hong, Ser Gi, E-mail: sergihong@khu.ac.kr [Department of Nuclear Engineering, Kyung Hee University, Deogyeong-daero, GiHeung-gu, Yongin, Gyeonggi-do 446-701 (Korea, Republic of); Shin, Ho Choel [Core and Fuel Analysis Group, Korea Hydro & Nuclear Power Central Research Institute (KHNP-CRI), Daejon 305-343 (Korea, Republic of)

    2017-04-01

    Highlights: • New advanced burnable poison rods (BPR) are suggested for low boron operation in PWR. • The new SMR cores have long cycle length of ∼4.5 EFPYs with low boron concentration. • The SMR core satisfies all the design targets and constraints. - Abstract: In this paper, new small long-cycle PWR (Pressurized Water Reactor) cores for low boron concentration operation are designed by employing advanced burnable poison rods (BPRs) in which the BISO (Bi-Isotropic) particles of burnable poison are distributed in a SiC matrix. The BPRs are designed by adjusting the kernel diameter, the kernel material and the packing fraction to effectively reduce the excess reactivity in order to reduce the boron concentration in the coolant and achieve a flat change in excess reactivity over a long operational cycle. In addition, axial zoning of the BPRs was suggested to improve the core performances, and it was shown that the suggested axial zoning of BPRs considerably extends the cycle length compared to a core with no BPR axial zoning. The results of the core physics analyses showed that the cores using BPRs with a B{sub 4}C kernel have long cycle lengths of ∼4.5 EFPYs (Effective Full Power Years), small maximum CBCs (Critical Boron Concentration) lower than 370 ppm, low power peaking factors, and large shutdown margins of control element assemblies.

  9. Neutron activation analysis of certified samples by the absolute method

    Science.gov (United States)

    Kadem, F.; Belouadah, N.; Idiri, Z.

    2015-07-01

    The nuclear reactions analysis technique is mainly based on the relative method or the use of activation cross sections. In order to validate nuclear data for the calculated cross section evaluated from systematic studies, we used the neutron activation analysis technique (NAA) to determine the various constituent concentrations of certified samples for animal blood, milk and hay. In this analysis, the absolute method is used. The neutron activation technique involves irradiating the sample and subsequently performing a measurement of the activity of the sample. The fundamental equation of the activation connects several physical parameters including the cross section that is essential for the quantitative determination of the different elements composing the sample without resorting to the use of standard sample. Called the absolute method, it allows a measurement as accurate as the relative method. The results obtained by the absolute method showed that the values are as precise as the relative method requiring the use of standard sample for each element to be quantified.

  10. Absolutely relative or relatively absolute: violations of value invariance in human decision making.

    Science.gov (United States)

    Teodorescu, Andrei R; Moran, Rani; Usher, Marius

    2016-02-01

    Making decisions based on relative rather than absolute information processing is tied to choice optimality via the accumulation of evidence differences and to canonical neural processing via accumulation of evidence ratios. These theoretical frameworks predict invariance of decision latencies to absolute intensities that maintain differences and ratios, respectively. While information about the absolute values of the choice alternatives is not necessary for choosing the best alternative, it may nevertheless hold valuable information about the context of the decision. To test the sensitivity of human decision making to absolute values, we manipulated the intensities of brightness stimuli pairs while preserving either their differences or their ratios. Although asked to choose the brighter alternative relative to the other, participants responded faster to higher absolute values. Thus, our results provide empirical evidence for human sensitivity to task irrelevant absolute values indicating a hard-wired mechanism that precedes executive control. Computational investigations of several modelling architectures reveal two alternative accounts for this phenomenon, which combine absolute and relative processing. One account involves accumulation of differences with activation dependent processing noise and the other emerges from accumulation of absolute values subject to the temporal dynamics of lateral inhibition. The potential adaptive role of such choice mechanisms is discussed.

  11. Boron deactivation in heavily boron-doped Czochralski silicon during rapid thermal anneal: Atomic level understanding

    International Nuclear Information System (INIS)

    Gao, Chao; Dong, Peng; Yi, Jun; Ma, Xiangyang; Yang, Deren; Lu, Yunhao

    2014-01-01

    The changes in hole concentration of heavily boron (B)-doped Czochralski silicon subjected to high temperature rapid thermal anneal (RTA) and following conventional furnace anneal (CFA) have been investigated. It is found that decrease in hole concentration, namely, B deactivation, is observed starting from 1050 °C and increases with RTA temperature. The following CFA at 300–500 °C leads to further B deactivation, while that at 600–800 °C results in B reactivation. It is supposed that the interaction between B atoms and silicon interstitials (I) thus forming BI pairs leads to the B deactivation during the high temperature RTA, and, moreover, the formation of extended B 2 I complexes results in further B deactivation in the following CFA at 300–500 °C. On the contrary, the dissociation of BI pairs during the following CFA at 600–800 °C enables the B reactivation. Importantly, the first-principles calculation results can soundly account for the above-mentioned supposition

  12. Boron deactivation in heavily boron-doped Czochralski silicon during rapid thermal anneal: Atomic level understanding

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Chao; Dong, Peng; Yi, Jun; Ma, Xiangyang, E-mail: luyh@zju.edu.cn, E-mail: mxyoung@zju.edu.cn; Yang, Deren [State Key Laboratory of Silicon Materials and Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Lu, Yunhao, E-mail: luyh@zju.edu.cn, E-mail: mxyoung@zju.edu.cn [International Center for New-Structured Materials and Laboratory of New-Structured Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China)

    2014-01-20

    The changes in hole concentration of heavily boron (B)-doped Czochralski silicon subjected to high temperature rapid thermal anneal (RTA) and following conventional furnace anneal (CFA) have been investigated. It is found that decrease in hole concentration, namely, B deactivation, is observed starting from 1050 °C and increases with RTA temperature. The following CFA at 300–500 °C leads to further B deactivation, while that at 600–800 °C results in B reactivation. It is supposed that the interaction between B atoms and silicon interstitials (I) thus forming BI pairs leads to the B deactivation during the high temperature RTA, and, moreover, the formation of extended B{sub 2}I complexes results in further B deactivation in the following CFA at 300–500 °C. On the contrary, the dissociation of BI pairs during the following CFA at 600–800 °C enables the B reactivation. Importantly, the first-principles calculation results can soundly account for the above-mentioned supposition.

  13. Response of nitrogen metabolism to boron toxicity in tomato plants.

    Science.gov (United States)

    Cervilla, L M; Blasco, B; Ríos, J J; Rosales, M A; Rubio-Wilhelmi, M M; Sánchez-Rodríguez, E; Romero, L; Ruiz, J M

    2009-09-01

    Boron (B) toxicity has become important in areas close to the Mediterranean Sea where intensive agriculture has been developed. The objective of this research was to study the effects of B toxicity (0.5 mM and 2.0 mM B) on nitrogen (N) assimilation of two tomato cultivars that are often used in these areas. Leaf biomass, relative leaf growth rate (RGR(L)), concentration of B, nitrate (NO(3) (-)), ammonium (NH(4) (+)), organic N, amino acids and soluble proteins, as well as nitrate reductase (NR), nitrite reductase (NiR), glutamine synthase (GS), glutamate synthetase (GOGAT) and glutamate dehydrogenase (GDH) activities were analysed in leaves. Boron toxicity s