WorldWideScience

Sample records for black nickel

  1. Performance evaluation of two black nickel and two black chrome solar collectors

    Science.gov (United States)

    Losey, R.

    1977-01-01

    The test program was based on the evaluation of four unique solar collectors described below: (1) black nickel collector surface with a desiccant drying bed, (2) black nickel collector surface without a desiccant drying bed, (3) black chrome collector surface with a dessicant drying bed, and (4) black chrome collector surface without a desiccant drying bed. The test program included three distinct phases: Initial performance evaluation, natural environmental aging, and post-aging performance evaluation. Results of Phase III testing conclusively indicated a higher normalized efficiency for Black Chrome surfaces when compared to Black Nickel.

  2. Black nickel-cobalt selective coatings for solar energy conversion

    Energy Technology Data Exchange (ETDEWEB)

    Srinivasan, K.N.; Selvam, M.; Shenoi, B.A.; Shanmugam, N.V.; John, S.; Annamalai, M.; Iyer, M.V.; Nirmala, K.A.; Venkatesh, P.; Prasad, C.R.; Subramani, C.

    1982-01-01

    The development of black nickel-cobalt selective coating for solar energy conversion is reported. This coating has been produced by plating nickel-cobalt alloy from suitable electrolyte and then immersion blackening in weak sulphuric acid. The effect of plating time, current density and immersion time, in acid with respect to absorptance and emittance were studied. Thermal cycling test and stagnation temperature measurement was also carried out.

  3. Selective coating for solar panels. [using black chrome and black nickel

    Science.gov (United States)

    Mcdonald, G. E. (Inventor)

    1977-01-01

    The energy absorbing properties of solar heating panels are improved by depositing a black chrome coating of controlled thickness on a specially prepared surface of a metal substrate. The surface is prepared by depositing a dull nickel on the substrate, and the black chrome is plated on this low emittance surface to a thickness between 0.5 micron and 2.5 microns.

  4. High emittance black nickel coating on copper substrate for space applications

    Energy Technology Data Exchange (ETDEWEB)

    Somasundaram, Soniya, E-mail: jrf0013@isac.gov.in; Pillai, Anju M., E-mail: anjum@isac.gov.in; Rajendra, A., E-mail: rajendra@isac.gov.in; Sharma, A.K., E-mail: aks@isac.gov.in

    2015-09-15

    Highlights: • High emittance black nickel coating is obtained on copper substrate. • The effect of various process parameters on IR emittance is studied systematically. • Process parameters are optimized to develop a high emittance black nickel coating. • Coating obtained using the finalized parameters exhibited an emittance of 0.83. • SEM and EDAX are used for coating characterization. - Abstract: Black nickel, an alloy coating of zinc and nickel, is obtained on copper substrate by pulse electrodeposition from a modified Fishlock bath containing nickel sulphate, nickel ammonium sulphate, zinc sulphate and ammonium thiocyanate. A nickel undercoat of 4–5 μm thickness is obtained using Watts bath to increase the corrosion resistance and adhesion of the black nickel coating. The effect of bath composition, temperature, solution pH, current density and plating time on the coating appearance and corresponding infra-red emittance of the coating is investigated systematically. Process parameters are optimized to develop a high emittance space worthy black nickel coating to improve the heat radiation characteristics. The effect of the chemistry of the plating bath on the coating composition was studied using energy dispersive X-ray analysis (EDAX) of the coatings. The 5–6 μm thick uniform jet black zinc–nickel alloy coating obtained with optimized process exhibited an emittance of 0.83 and an absorbance of 0.92. The zinc to nickel ratio of black nickel coatings showing high emittance and appealing appearance was found to be in the range 2.3–2.4.

  5. High emittance black nickel coating on copper substrate for space applications

    International Nuclear Information System (INIS)

    Highlights: • High emittance black nickel coating is obtained on copper substrate. • The effect of various process parameters on IR emittance is studied systematically. • Process parameters are optimized to develop a high emittance black nickel coating. • Coating obtained using the finalized parameters exhibited an emittance of 0.83. • SEM and EDAX are used for coating characterization. - Abstract: Black nickel, an alloy coating of zinc and nickel, is obtained on copper substrate by pulse electrodeposition from a modified Fishlock bath containing nickel sulphate, nickel ammonium sulphate, zinc sulphate and ammonium thiocyanate. A nickel undercoat of 4–5 μm thickness is obtained using Watts bath to increase the corrosion resistance and adhesion of the black nickel coating. The effect of bath composition, temperature, solution pH, current density and plating time on the coating appearance and corresponding infra-red emittance of the coating is investigated systematically. Process parameters are optimized to develop a high emittance space worthy black nickel coating to improve the heat radiation characteristics. The effect of the chemistry of the plating bath on the coating composition was studied using energy dispersive X-ray analysis (EDAX) of the coatings. The 5–6 μm thick uniform jet black zinc–nickel alloy coating obtained with optimized process exhibited an emittance of 0.83 and an absorbance of 0.92. The zinc to nickel ratio of black nickel coatings showing high emittance and appealing appearance was found to be in the range 2.3–2.4

  6. Mobile nickel content in calcareous black soils of Rajac

    OpenAIRE

    Đorđević Aleksandar R.

    2002-01-01

    A description of mobile Ni contents in various subtypes of calcareous black soils from the area of the mountain massif of Rajac, is given in the present paper. A hundred soil samples were analysed in all, originating from four subtypes of calcareous black soil (organogenic, organo-mineral, brownized and loessivized black soils). The extraction of mobile Ni was carried out with 1.0 N HCl and its content was determined by atomic absorption spectrophotometry. The obtained results indicate that m...

  7. Improvement of black nickel coatings. [product development for use in solar collectors

    Science.gov (United States)

    Peterson, R. E.; Lin, J. H.

    1976-01-01

    Selectively absorbing black nickel coatings are among the most optically efficient low cost coatings for use on flat plate solar collectors. However, a current Ni-Zn-S-O coating in use is quite susceptible to a humid environment, degrading badly in less than ten days at 38 C (100 F) at 95 percent relative humidity. Therefore, a black nickel formula was developed which can withstand such exposures with no loss of optical efficiency, solar absorption of 0.92 and an infrared emittance (at 100 C) of 1.00 were still present after 14 days of humidity exposure. This compares to a solar absorptance of only 0.72 for the previous formula after a similar time period. The electroplating bath and conditions were changed to obtain the more stable coating configuration. The effect of bath composition, temperature, pH, and plating current density and time on the coating composition, spectral optical properties and durability were investigated systematically.

  8. Research Progress in Solderable Black Pad of Electroless Nickel/Immersion Gold

    Institute of Scientific and Technical Information of China (English)

    Liu Haiping; Li Ning; Bi Sifu; Li Deyu

    2007-01-01

    Electroless nickel/immersion gold (ENIG) technology is widely used as one of the surface final finish for electronics packaging substrate and printed circuit board (PCB), providing a protective, conductive and solderable surface. However, there is a solder joint interfacial brittle fracture (or solderability failure) of using the ENIG coating. The characteristics and the application of ENIG technology were narrated in this paper. The research progress on the solderability failure of ENIG was introduced. The mechanism of "black pad" and the possible measure of eliminating or alleviating the "black pad" were also introduced. The development direction and market prospects of ENIG were prospected.

  9. Corrosion Properties of Black Nickel Coating on Aluminum for Solar Heating Applications

    International Nuclear Information System (INIS)

    A simple process of electroplated bright nickel is investigated to produce ultra high solar absorber coating on the aluminum substrates, which has high corrosion resistance. The corrosion resistance varies with deposition conditions of black Ni layer on the coating bath. Evaluation of the coatings was carried out by measurement of corrosion resistance and optical properties optimized in order to give the maximum selectivity (a/e) value. The deposition parameters are found to affect corrosion resistance of the coat. Corrosion resistance of the films was evaluated in 3.5% sodium chloride solution potentiodynamic polarization. The prepared samples were characterized using potentiostat, galvanostat Autolab, X-ray diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM), UV-VIS-NIR,V-570 Jasco, Japan, spectrophotometer. XRD patterns showed that the ZnS and ZnS:Ni nanoparticles have zinc blend structure with the crystallite sizes of about 6-25 nm range. The results also showed that applying the coat on aluminum substrates resulted in best bath composition of NiSO4, ZnSO4, NH4NiSO4, NaSCN, at Ph=5.6 to 5.9, Temp. 55°C and current density 0.02 A/cm2. The coating has emittance 0.31% and absorption 98.52%, selectivity about (α/ε) = 184.98, and Corrosion rate= 0.00916 mm/year.

  10. THE INFLUENCE OF NICKEL OXIDE COMBINED WITH THE INFLUENCE OF ALTERNATING MAGNETIC FIELDS ON BIOLOGICAL PROPERTIES OF ALKALINITY BLACK SOILS OF THE CRIMEA (THE RUSSIAN FEDERATION

    Directory of Open Access Journals (Sweden)

    Minnikova T. V.

    2014-12-01

    Full Text Available In the article we have investigated the influence of nickel oxide in the amount of 100, 1000 mg/kg of the soil (1, 10 MPC, combined with the influence of an alternating magnetic field of induction of 50, 100 and 650 µT power frequency of 50 Hz on the biological properties of alkalinity black soil

  11. Optical Properties of Black Nickel-Zinc Coating on Aluminum For Solar Heating Applications

    International Nuclear Information System (INIS)

    The present study describes the performance of selective coatings to get maximum solar absorbance and minimum thermal emittance. Aluminum substrates, covered with Ni electroplated base layer, have been used to show the influence of thickness and deposition condition of black Ni layer on the optical performance of selective coatings. Evaluation of the coatings was carried out by adhesion, measurement of coating thickness and optical properties. The deposition process parameters are optimized in order to give the maximum selectivity (a/s) value. The deposition parameters are found to affect the thickness of the coat. As the coat thickness decreases the absorptive increases and the emissivity decreases. The structure and optical properties of the prepared samples were characterized using X-ray diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM), UV- VIS - NIR, V-570 Jasco, Japan, spectrophotometer and XRD patterns showed that the ZnS and ZnS:Ni nanoparticles have zinc blended structure with the crystallite sizes of about 6-25 nm range. The value of optical band gap has been found to be in range 3.2- 3.7 eV The results also show that applying the coat on aluminum substrates resulted in best bath composition NiSCU, ZnSC>4, NFLiNiSO4, NaSCN, at ph = 5.6 to 5.9 and temp. 55°C current density 0.02 mA/cm , have emittance 0.31% and absorption 98.52% and selectivity about (a/ s) =184.98.

  12. Nickel Dermatitis - Nickel Excretion

    DEFF Research Database (Denmark)

    Menné, T.; Thorboe, A.

    1976-01-01

    Nickel excretion in urine in four females -sensitive to nickel with an intermittent dyshidrotic eruption was measured with flameless atomic absorption. Excretion of nickel was found to be increased in association with outbreaks of vesicles. The results support the idea that the chronic condition ...

  13. Electrochemical deposition of black nickel solar absorber coatings on stainless steel AISI316L for thermal solar cells

    OpenAIRE

    Lira-Cantú, Monica; Morales Sabio, Angel; Brustenga, Alex; Gómez-Romero, P.

    2005-01-01

    We report the electrochemical deposition of nanostructured nickel-based solar absorber coatings on stainless steel AISI type 316L. A sol–gel silica-based antireflection coating, from TEOS, was also applied to the solar surface by the dip-coating method. We report our initial results and analyze the influence of the stainless steel substrate on the final total reflectance properties of the solar absorber. The relation between surface morphology, observed by SEM and AFM, the comp...

  14. Electrochemical reduction and oxidation pathways for Reactive Black 5 dye using nickel electrodes in divided and undivided cells

    International Nuclear Information System (INIS)

    Highlights: ► Ni electrodes were used for the mild degradation of the azo dye Reactive Black 5. ► Potentiostatic degradation was performed in undivided and divided cells. ► Degradation by-products were detected and monitored by RP-HPLC and LC–MS/MS. ► Small alkylsulfonyl phenol and isoxazole derivatives were identified. ► The cathodic and anodic degradation pathways for Reactive Black 5 were elucidated. - Abstract: The cathodic reduction and anodic ·OH-mediated oxidation of the azo dye Reactive Black 5 (RB5) have been studied potentiostatically by using undivided and divided cells with a Ni-polyvinylchloride (Ni-PVC) composite cathode and a Ni wire mesh anode. Solutions of 50–100 cm3 of 20–80 mg dm−3 RB5 in 0.1 mol dm−3 KOH were degraded to assess the effect of electrolysis time and electrode potentials on the infrared and absorbance spectra, as well as on the decay of the total organic carbon and chemical oxygen demand. Reversed-phase high performance liquid chromatography (RP-HPLC) with ion-pairing and diode array detection (ion pair chromatography), along with coupling to tandem mass spectrometry (LC–MS/MS), were used for the identification of the aromatic degradation by-products and monitoring their time course. These analyses revealed the progressive conversion of the RB5 dye to simpler molecules with m/z 200, 369.5 and 547 under the direct action of the electron at the cathode and the formation of polar compounds such as alkylsulfonyl phenol derivatives with m/z 201, 185 and 171 by the ·OH mediation at the anode. From these results, the electrochemical reduction and oxidation pathways for the RB5 dye were elucidated.

  15. NICKEL HYDROXIDES

    Energy Technology Data Exchange (ETDEWEB)

    MCBREEN,J.

    1997-11-01

    Nickel hydroxides have been used as the active material in the positive electrodes of several alkaline batteries for over a century. These materials continue to attract a lot of attention because of the commercial importance of nickel-cadmium and nickel-metal hydride batteries. This review gives a brief overview of the structure of nickel hydroxide battery electrodes and a more detailed review of the solid state chemistry and electrochemistry of the electrode materials. Emphasis is on work done since 1989.

  16. Automatic Potential Titration of Thiocyanate and Chloride Ions in Black Nickel Plating Bath%黑镍镀液中硫氰酸根和氯离子的自动电位滴定

    Institute of Scientific and Technical Information of China (English)

    丘山; 丘星初; 曾家民; 刘星; 刘海燕

    2011-01-01

    The conditions and methods for automatic potential titration of thiocyanate and chloride ions were investigated. The results show that by selecting silver electrode as indication electrode, model 217 Double-liquid connecting electrode as reference electrode, the titration can be continuously operated in nitric acid medium, and these two kinds of ions can also be titrated by steps. When used in analyzing black nickel plating bath, it is easy and fast to operate, and the accuracy and precision can completely meet the demands of production.%研究了用自动电位滴定测定硫氰酸根和氯离子的条件及方法.结果表明:选用银电极为指示电极,217型双液接电极为参比电极,在硝酸介质中既能连续滴定也能分步滴定这两种离子.应用于黑镍镀液分析,方法简便快捷,分析的准确度和精密度完全能满足生产需要.

  17. Refinement in black chrome for use as a solar selective coating

    Science.gov (United States)

    Mcdonald, G. E.

    1974-01-01

    Black chrome is significant as a solar selective coating because the current extensive use of black chrome in the electroplating industry as a durable decorative finish makes black chrome widely available on a commercial scale and potentially low in cost as a solar selective coating. Black-chrome deposits were modified by underplating with dull nickel or by being plated on rough surfaces. Both of these procedures increased the visible absorptance. There was no change in the infrared reflectance for the dull-nickel - black-chrome combination from that reported for the bright-nickel - black-chrome combination. However, the bright-nickel - black-chrome coating plated on rough surfaces indicated a slight decrease in infrared reflectance. As integrated over the solar spectrum for air mass 2, the reflectance of the dull-nickel - black-chrome coating was 0.077, of the bright-nickel - black-chrome coating plated on a 0.75-micron (30-microinch) surface was 0.070, of the bright-nickel - black-chrome coating plated on a 2.5 micron (100-microinch) surface was 0.064. The corresponding values for the bright-nickel - black-chrome coating on a 0.0125-micron (0.5-microinch) surface, two samples of black nickel, and two samples of Nextrel black paint were 0.132, 0.123, 0.133, and 0.033, respectively.

  18. Distinct mechanisms of oxidative DNA damage induced by carcinogenic nickel subsulfide and nickel oxides.

    OpenAIRE

    Kawanishi, Shosuke; Oikawa, Shinji; Inoue, Sumiko; Nishino, Kohsuke

    2002-01-01

    The U.S. National Toxicology Program has shown clear evidence of carcinogenicity of nickel subsulfide (Ni(3)S(2)) and some evidence of carcinogenicity of NiO (green) in rats. In the present study, DNA damage in cultured cells and in lungs of rats induced by nickel compounds was investigated to clarify the mechanism of nickel carcinogenesis. In cultured HeLa cells, Ni(3)S(2) induced a significant increase in 8-hydroxydeoxyguanosine (8-OH-dG) formation, whereas NiO (black), NiO (green), and NiS...

  19. Synthesis, structure characterization and catalytic activity of nickel tungstate nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Pourmortazavi, Seied Mahdi, E-mail: pourmortazavi@yahoo.com [Faculty of Material and Manufacturing Technologies, Malek Ashtar University of Technology, Tehran (Iran, Islamic Republic of); Rahimi-Nasrabadi, Mehdi, E-mail: rahiminasrabadi@gmail.com [Department of Chemistry, Imam Hossein University, Tehran (Iran, Islamic Republic of); Khalilian-Shalamzari, Morteza [Department of Chemistry, Imam Hossein University, Tehran (Iran, Islamic Republic of); Zahedi, Mir Mahdi; Hajimirsadeghi, Seiedeh Somayyeh [Islamic Azad University, Varamin Pishva Branch, Varamin (Iran, Islamic Republic of); Omrani, Ismail [Department of Chemistry, Imam Hossein University, Tehran (Iran, Islamic Republic of)

    2012-12-15

    Graphical abstract: NiWO{sub 4} nanoparticles were prepared via precipitation technique. Experimental parameters of procedure were optimized statistically. Highlights: Black-Right-Pointing-Pointer NiWO{sub 4} spherical nanoparticles were synthesized via direct precipitation method. Black-Right-Pointing-Pointer Taguchi robust design was used for optimization of synthesis reaction parameters. Black-Right-Pointing-Pointer Composition and structural properties of NiWO{sub 4} nanoparticles were characterized. Black-Right-Pointing-Pointer EDAX, XRD, SEM, FT-IR, UV-vis and photoluminescence techniques were employed. Black-Right-Pointing-Pointer Catalytic activity of the product in a cyclo-addition reaction was investigated. - Abstract: Taguchi robust design was applied to optimize experimental parameters for controllable, simple and fast synthesis of nickel tungstate nanoparticles. NiWO{sub 4} nanoparticles were synthesized by precipitation reaction involving addition of nickel ion solution to the tungstate aqueous reagent and then formation of nickel tungstate nucleolus which are insoluble in aqueous media. Effects of various parameters such as nickel and tungstate concentrations, flow rate of reagent addition and reactor temperature on diameter of synthesized nickel tungstate nanoparticles were investigated experimentally by the aid of orthogonal array design. The results for analysis of variance (ANOVA) showed that particle size of nickel tungstate can be effectively tuned by controlling significant variables involving nickel and tungstate concentrations and flow rate; while, temperature of the reactor has a no considerable effect on the size of NiWO{sub 4} particles. The ANOVA results proposed the optimum conditions for synthesis of nickel tungstate nanoparticles via this technique. Also, under optimum condition nanoparticles of NiWO{sub 4} were prepared and their structure and chemical composition were characterized by means of EDAX, XRD, SEM, FT-IR spectroscopy, UV

  20. Contaminated nickel scrap processing

    International Nuclear Information System (INIS)

    The DOE will soon choose between treating contaminated nickel scrap as a legacy waste and developing high-volume nickel decontamination processes. In addition to reducing the volume of legacy wastes, a decontamination process could make 200,000 tons of this strategic metal available for domestic use. Contaminants in DOE nickel scrap include 234Th, 234Pa, 137Cs, 239Pu (trace), 60Co, U, 99Tc, and 237Np (trace). This report reviews several industrial-scale processes -- electrorefining, electrowinning, vapormetallurgy, and leaching -- used for the purification of nickel. Conventional nickel electrolysis processes are particularly attractive because they use side-stream purification of process solutions to improve the purity of nickel metal. Additionally, nickel purification by electrolysis is effective in a variety of electrolyte systems, including sulfate, chloride, and nitrate. Conventional electrorefining processes typically use a mixed electrolyte which includes sulfate, chloride, and borate. The use of an electrorefining or electrowinning system for scrap nickel recovery could be combined effectively with a variety of processes, including cementation, solvent extraction, ion exchange, complex-formation, and surface sorption, developed for uranium and transuranic purification. Selected processes were reviewed and evaluated for use in nickel side-stream purification. 80 refs

  1. Black to Black

    DEFF Research Database (Denmark)

    Langkjær, Michael Alexander

    2012-01-01

    Pop musicians performing in black stage costume take advantage of cultural traditions relating to matters black. Stylistically, black is a paradoxical color: although a symbol of melancholy, pessimism, and renunciation, black also expresses minimalist modernity and signifies exclusivity (as...... is hinted by Rudyard Kipling’s illustration of ‘The [Black] Cat That Walked by Himself’ in his classic children’s tale). It was well understood by uniformed Anarchists, Fascists and the SS that there is an assertive presence connected with the black-clad figure. The paradox of black’s abstract elegance......-styled references to, among other things, the culturally and ideologically effervescent interwar-period have made me curious as to what alternative possibilities – for instance ‘emancipation’ – a comparative analysis might disclose concerning the visual rhetoric of black. Thus, in conclusion, it is briefly...

  2. Nickel laterites, origin and climate

    OpenAIRE

    Thorne, Robert L.

    2011-01-01

    Nickel laterites account for ?40 % of global nickel production and contain 60 % of the world's total land based nickel resources. Despite the importance of these deposits published studies, detailing their morphology and formation processes are relatively few and the interaction of variables responsible for the formation of different nickel laterites are poorly understood. To better understand the process of nickel laterite formation, the Caldag and Bitincke paleodeposits were studied and...

  3. Nickel hydrogen capacity loss

    Science.gov (United States)

    Goualard, Jacques; Paugam, D.; Borthomieu, Y.

    1993-01-01

    The results of tests to assess capacity loss in nickel hydrogen cells are presented in outline form. The effects of long storage (greater than 1 month), high hydrogen pressure storage, high cobalt content, and recovery actions are addressed.

  4. Graphene–nickel composites

    Energy Technology Data Exchange (ETDEWEB)

    Kuang, Da [State Key Laboratory of Metal Matrix Composites, Shanghai Jiaotong University, Shanghai, 200240 (China); Dept. of Mechanical and Manufacturing Engineering, University of Calgary, Calgary, AB, Canada T2N 1N4 (Canada); Xu, Liye [State Key Laboratory of Metal Matrix Composites, Shanghai Jiaotong University, Shanghai, 200240 (China); Liu, Lei, E-mail: anodic@sjtu.edu.cn [State Key Laboratory of Metal Matrix Composites, Shanghai Jiaotong University, Shanghai, 200240 (China); Hu, Wenbin; Wu, Yating [State Key Laboratory of Metal Matrix Composites, Shanghai Jiaotong University, Shanghai, 200240 (China)

    2013-05-15

    Graphene/nickel composites were prepared by electrodeposition in a nickel sulfamate solution with graphene oxide (GO) sheets in suspension. Raman spectra demonstrated that the GO sheets had been reduced during the electrodeposition process and the graphene content was 0.12 wt%. X-ray diffraction patterns showed the preferred orientation of nickel growth changing from (2 0 0) to (1 1 1) in the composites. Transmission and scanning electron microscopy images were used to help explain how the introduction of graphene substrates leads to the change of preferred orientation. Measurements showed the thermal conductivity of the composites to be about 15% more than that of pure nickel electrodeposits. Significant improvement was also demonstrated in the hardness measured by nanoindentation.

  5. Soil, nickel and low nickel food

    Science.gov (United States)

    Chami, Ziad Al; Cavoski, Ivana; Mondelli, Donato; Mimiola, Giancarlo; Miano, Teodoro

    2013-04-01

    Nickel is an ubiquitous trace element and occurs in soil, water, air and in the biosphere. Ni is an essential element for several plants, microorganisms and vertebrates. Human requirement for Ni has not been conclusively demonstrated. Nickel is normally present in human tissues at low concentration and, under conditions of high exposure, these levels may increase significantly. Food is the major source of Ni exposure. Nickel is present in many food products, especially vegetables. The amount of Ni present in vegetables is increasing because of environmental contamination and cultural practices. It has been demonstrated that the consumption of a Ni-rich diet can cause an increase of immunological disorders including Systemic Ni Allergy Syndrome (SNAS). The SNAS patients are currently treated with a diet that is closely Ni-free. Therefore, there is a need to produce certified and guaranteed vegetables with a low Ni concentration in the market. The proposed research aims to develop new methods for vegetable production and innovative cultural practices through a suitable choice of agricultural soil, cultivar, amendments and fertilizers as well as good agricultural practices in order to reduce Ni plant uptake and its translocation to the edible plant parts and therefore to produce Ni-free food products for SNAS patients.

  6. Black rings

    International Nuclear Information System (INIS)

    A black ring is a five-dimensional black hole with an event horizon of topology S1 x S2. We provide an introduction to the description of black rings in general relativity and string theory. Novel aspects of the presentation include a new approach to constructing black ring coordinates and a critical review of black ring microscopics. (topical review)

  7. The cost of nickel allergy

    DEFF Research Database (Denmark)

    Hamann, Carsten R; Hamann, Dathan; Hamann, Curtis;

    2013-01-01

    Background. Nickel is widely used in coins; nickel may cause contact allergy and allergic contact dermatitis in those who handle them. Objectives. To investigate alloy use, coin composition and nickel and cobalt release for a worldwide selection of currently circulating coins. Materials and methods...

  8. Nickel in tap water

    DEFF Research Database (Denmark)

    Andersen, Klaus Ejner; Nielsen, G D; Flyvholm, Morten;

    1983-01-01

    Nickel analyses of tap water from several sources in Copenhagen gave up to 490 X 10(-6) g X 1(-1) in the first 250 ml portions. Hot water gave higher values than cold water. After flushing for 5 min, low values were found. Considerable variation from time to time and from tap to tap was found...

  9. Black Consciousness

    Science.gov (United States)

    Hraba, Joseph; Siegman, Jack

    1974-01-01

    Black militancy is treated as an instance of class consciousness with criteria and scales developed to measure black consciousness and "self-placement" into black consciousness. These dimensions are then investigated with respect to the social and symbolic participation in the ideology of the black movement on the part of a sample of black…

  10. Carbon deposition on nickel ferrites and nickel-magnetite surfaces

    International Nuclear Information System (INIS)

    Carbon deposition on Commercial Advanced Gas-Cooled Reactor (CAGR) fuel cladding and heat exchanger surfaces lowers heat transfer efficiency and increases fuel pin temperatures. Several types of deposit have been identified including both thin dense layers and also low density columnar deposits with filamentary or convoluted laminar structure. The low-density types are often associated with particles containing iron, nickel or manganese. To identify the role of nickel in the deposition process surfaces composed of nickel-iron spinels or metallic nickel/magnetite mixtures have been exposed to γ radiation in a gas environment simulating that in the reactor. Examination of these surfaces by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) have shown that while metallic nickel (Ni(O)) catalyses the formation of filamentary low density carbon deposits, the presence of divalent nickel (Ni(II)) sites in spinel type oxides is associated only with dense deposits. (author)

  11. Nickel ferrule applicators: a source of nickel exposure in children.

    Science.gov (United States)

    Jacob, Sharon E; Silverberg, Jonathan I; Rizk, Christopher; Silverberg, Nanette

    2015-01-01

    Eye makeup has been investigated for nickel content and found to have no direct association with nickel allergy and cosmetic dermatitis. However, the tools used (e.g., eyelash curlers, hairdressing scissors, hair curlers, and eye shadow and makeup applicators) may be sources. Nickel is ubiquitous and a wide range of sources have been reported, and makeup applicators (ferrules) now join the list. PMID:25639728

  12. Radiosensitization by nickel lapachol

    International Nuclear Information System (INIS)

    The properties of interest in the radiosensitization of a metal complex, nickel lapachol, are compared with those of the 2-nitroimidazole, misonidazole. These very different compounds were found to be surprisingly similar in terms of their reduction potential (-370 mV), enhancement ratios for killing of hypoxic Chinese hamster ovary cells by X-irradiation, and enhancement of DNA breaks in hypoxia. For nitroimidazoles, the sensitization depends on 'electron affinity', reduction of the nitro group; for nickel lapachol it is the metal which is necessary for reduction, yet the sensitization efficiencies are remarkably close. However, the metal complex has additional activities (some sensitization in aerobic cells; increased sensitization with preincubation) which are as yet unexplained but are assumed to be related to the nature of the naphthoquinone ligand, rather than to the reduction of the metal. (Author)

  13. Nickel: makes stainless steel strong

    Science.gov (United States)

    Boland, Maeve A.

    2012-01-01

    Nickel is a silvery-white metal that is used mainly to make stainless steel and other alloys stronger and better able to withstand extreme temperatures and corrosive environments. Nickel was first identified as a unique element in 1751 by Baron Axel Fredrik Cronstedt, a Swedish mineralogist and chemist. He originally called the element kupfernickel because it was found in rock that looked like copper (kupfer) ore and because miners thought that "bad spirits" (nickel) in the rock were making it difficult for them to extract copper from it. Approximately 80 percent of the primary (not recycled) nickel consumed in the United States in 2011 was used in alloys, such as stainless steel and superalloys. Because nickel increases an alloy's resistance to corrosion and its ability to withstand extreme temperatures, equipment and parts made of nickel-bearing alloys are often used in harsh environments, such as those in chemical plants, petroleum refineries, jet engines, power generation facilities, and offshore installations. Medical equipment, cookware, and cutlery are often made of stainless steel because it is easy to clean and sterilize. All U.S. circulating coins except the penny are made of alloys that contain nickel. Nickel alloys are increasingly being used in making rechargeable batteries for portable computers, power tools, and hybrid and electric vehicles. Nickel is also plated onto such items as bathroom fixtures to reduce corrosion and provide an attractive finish.

  14. Black Eye

    Science.gov (United States)

    ... eyesight if not treated. If both eyes are black after a head injury, it could signify a skull fracture or other serious injury. Next Black Eye Symptoms Related Ask an Ophthalmologist Answers How ...

  15. Black tea

    Science.gov (United States)

    ... diuretic to increase urine flow. Some people use black tea for preventing tooth decay and kidney stones. In combination with various other products, black tea is used for weight loss. In foods, ...

  16. Pulse Reversal Plating of Nickel and Nickel Alloys for MEMS

    DEFF Research Database (Denmark)

    Tang, Peter Torben

    2001-01-01

    Pulse plating has previously been reported to improve the properties of nickel and nickel alloy deposits. Typically, focus has been on properties such as grain size, hardness and smoothness. When pulse plating is to be utilized for micro electromechanical systems (MEMS), internal stress and...

  17. Point defects in nickel

    International Nuclear Information System (INIS)

    The defects in electron irradiated nickel (20 deg. K) or neutron irradiated nickel (28 deg. K) are studied by simultaneous analysis using the magnetic after-effect, electron microscopy and electrical resistivity recovery. We use zone refined nickel (99.999 per cent) which, for some experiments, is alloyed with a small amount of iron (for example 0.1 per cent Fe). The temperature dependant electrical recovery may be divided in four stages. The sub-stages IB (31 deg. K), IC (42 deg. K), ID (from to 57 deg. K) and IE (62 deg. K) of stage I are due to the disappearance of single interstitials into vacancies. The interstitial defect has a split configuration with a migration energy of about 0.15 eV. In the close pair which disappears in stage IB the interstitial is found to be in a 3. neighbour position whilst in stage ID it is near the direction from the vacancy. In stage IE there is no longer any interaction between the interstitial and the vacancy. The stage II is due to more complicated interstitial defects: di-interstitials for stage IIB (84 deg. K) and larger and larger interstitial loops for the following sub-stages. The loops may be seen by electron microscopy. Impurities can play the role of nucleation centers for the loops. Stages IIIA (370 deg. K) and IIIB (376 deg. K) are due to two types of di-vacancies. During stage IV (410 deg. K) the single vacancies migrate. Vacancy type loops and interstitial type loops grow concurrently and disappear at about 800 deg. K as observed by electron microscopy. (author)

  18. Performance of lightweight nickel electrodes

    Science.gov (United States)

    Britton, Doris L.

    1988-01-01

    The NASA Lewis Research Center is currently developing nickel electrodes for nickel-hydrogen (Ni-H2) batteries. These electrodes are lighter in weight and have higher energy densities than the heavier state-of-the-art (SOA) sintered nickel electrodes. In the present approach, lightweight materials or plaques are used as conductive supports for the nickel hydroxide active material. These plaques (fiber and felt, nickel plated plastic and graphite) are commercial products that are fabricated into nickel electrodes by electrochemically impregnating them with active material. Evaluation is performed in half cells structured in the bipolar configuration. Initial performance tests include capacity measurements at five discharge levels, C/2, 1.0C, 1.37C, 2.0C and 2.74C. The electrodes that pass the initial tests are life cycle tested in a low earth orbit regime at 80 percent depth of discharge. Different formulations of nickel fiber materials obtained from several manufacturers are currently being tested as possible candidates for nickel electrodes. One particular lightweight fiber mat electrode has accumulated over 3000 cycles to date, with stable capacity and voltage. Life and performance data of this electrode were investigated and presented. Good dimensional stability and active material adherence have been demonstrated in electrodes made from this lightweight plaque.

  19. Black Holes

    Science.gov (United States)

    Luminet, Jean-Pierre

    1992-09-01

    Foreword to the French edition; Foreword to the English edition; Acknowledgements; Part I. Gravitation and Light: 1. First fruits; 2. Relativity; 3. Curved space-time; Part II. Exquisite Corpses: 4. Chronicle of the twilight years; 5. Ashes and diamonds; 6. Supernovae; 7. Pulsars; 8. Gravitation triumphant; Part III. Light Assassinated: 9. The far horizon; 10. Illuminations; 11. A descent into the maelstrom; 12. Map games; 13. The black hole machine; 14. The quantum black hole; Part IV. Light Regained: 15. Primordial black holes; 16. The zoo of X-ray stars; 17. Giant black holes; 18. Gravitational light; 19. The black hole Universe; Appendices; Bibliography; Name index; Subject index.

  20. Formation and microstructure of nickel oxide films

    Energy Technology Data Exchange (ETDEWEB)

    Marcius, Marijan [Ruder Boskovic Institute, P.O. Box 180, HR-10002 Zagreb (Croatia); Ristic, Mira, E-mail: ristic@irb.hr [Ruder Boskovic Institute, P.O. Box 180, HR-10002 Zagreb (Croatia); Ivanda, Mile; Music, Svetozar [Ruder Boskovic Institute, P.O. Box 180, HR-10002 Zagreb (Croatia)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer Difference in NiO films formed on Ni plate or glass substrate were found. Black-Right-Pointing-Pointer NiO particle sizes on Ni plate changed from nano to micron dimensions. Black-Right-Pointing-Pointer NiO particle sizes on glass substrate changed from {approx}16 to {approx}27 nm. Black-Right-Pointing-Pointer Raman and UV/Vis/NIR spectra are related to the microstructure of NiO films. - Abstract: The formation and microstructure of NiO films on different substrates were monitored using XRD, Raman, UV/Vis/NIR and FE-SEM/EDS techniques. The formation of NiO films on Ni plates in air atmosphere between 400 and 800 Degree-Sign C was confirmed by XRD and Raman spectroscopy. The origin of Raman bands and corresponding Raman shifts in the samples are discussed. An increase in the size of NiO particles in the films from nano to micro dimensions was demonstrated. A change in the atomic ratio Ni:O with an increase in heating temperature was observed. Polished Ni plates coated with a thin Ni-acetate layer upon heating at high temperatures gave similar NiO microstructures on the surface like in the case of non-treated Ni plates. Glass substrates coated with thin Ni-acetate films upon heating between 400 and 800 Degree-Sign C yielded pseudospherical NiO nanoparticles. The dominant Raman band as an indicator of NiO formation on a glass substrate was shown. The formation of NiO nanoparticles on glass substrates with maximum size distribution from 16 to 27 nm in a broad temperature range from 400 to 800 Degree-Sign C can be explained by the absence of a constant source of metallic nickel which was present in the case of Ni plates.

  1. Electroplated tin-nickel coatings as a replacement for nickel to eliminate nickel dermatitis

    DEFF Research Database (Denmark)

    Møller, Per; Boyce, Jan M.; Nielsen, Lars Pleth

    has already been regulated by the nickel EU directive [94/27/EC] since 1994. In the present contribution tin/nickel alloy coatings (66.9 wt. % Sn), electrodeposited from a chloride/fluoride containing alloy electrolyte, will be presented as an alternative for both nickel and bright chromium coatings....... The main focus will be on the corrosion properties where the following corrosion investigations will be covered; corrosion potential measurements for the different coatings, estimation of corrosion rates for materials in galvanic coupling with tin/nickel coatings, salt spray test, medical tests and...... immersion test of tin/nickel coatings in artificial sweat. Copyright © (2013) by the National Association for Surface Finishing....

  2. Nickel Excretion in Urine after Oral Administration

    DEFF Research Database (Denmark)

    Menne, T.; Mikkelsen, H. I.; Solgaard, Per Bent

    1978-01-01

    In recent years the importance of internal exposure to nickel in patients with recurrent hand eczema and nickel allergy has become evident. The present study was performed in order to investigate the value of urinary nickel determinations as an index of oral nickel intake. After oral administrati...

  3. Synthesis and characterization of NiO nanoparticles by thermal decomposition of nickel linoleate and their optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Kalam, Abul, E-mail: abul_k33@yahoo.com [Department of Chemistry, Faculty of Science, King Khalid University, Abha 61413, P.O. Box 9004 (Saudi Arabia); Al-Sehemi, Abdullah G.; Al-Shihri, Ayed S. [Department of Chemistry, Faculty of Science, King Khalid University, Abha 61413, P.O. Box 9004 (Saudi Arabia); Du Gaohui [Zhejiang Key Laboratory for Reactive Chemistry on Solid Surfaces, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua 321004 (China); Ahmad, Tokeer [Nanochemistry Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi 110025 (India)

    2012-06-15

    Well dispersed nickel oxide nanoparticles have been synthesized successfully by direct calcination of nickel linoleate. The structure, morphology and properties of the nanoparticles were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy and ultraviolet-visible spectroscopy. Transmission electron microscopic studies show that nickel oxide nanoparticles are uniform with an average size of 14-20 nm. The optical band gap of 3.8 eV is obtained using UV-Visible spectroscopy which exhibits the red shift compared with the bulk counterpart. - Highlights: Black-Right-Pointing-Pointer Synthesis of metal oxide nanoparticles by using metal complexes as precursors. Black-Right-Pointing-Pointer Characterization of isolated nanoparticles using XRD, FTIR, SEM, TEM and HRTEM data. Black-Right-Pointing-Pointer The expected optical properties of these nanoparticles are clarified.

  4. Investigation of hydrogen evolution activity for the nickel, nickel-molybdenum nickel-graphite composite and nickel-reduced graphene oxide composite coatings

    Science.gov (United States)

    Jinlong, Lv; Tongxiang, Liang; Chen, Wang

    2016-03-01

    The nickel, nickel-molybdenum alloy, nickel-graphite and nickel-reduced graphene oxide composite coatings were obtained by the electrodeposition technique from a nickel sulfate bath. Nanocrystalline molybdenum, graphite and reduced graphene oxide in nickel coatings promoted hydrogen evolution reaction in 0.5 M H2SO4 solution at room temperature. However, the nickel-reduced graphene oxide composite coating exhibited the highest electrocatalytic activity for the hydrogen evolution reaction in 0.5 M H2SO4 solution at room temperature. A large number of gaps between 'cauliflower' like grains could decrease effective area for hydrogen evolution reaction in slight amorphous nickel-molybdenum alloy. The synergistic effect between nickel and reduced graphene oxide promoted hydrogen evolution, moreover, refined grain in nickel-reduced graphene oxide composite coating and large specific surface of reduced graphene oxide also facilitated hydrogen evolution reaction.

  5. Improvement of nickel steels production technology

    International Nuclear Information System (INIS)

    Investigated was the adjustment of nickel content in the furnace bath during the smelting of 12-20KhN3A steels. Tests were carried out to study the rate of solution of nickel in molten metal on introduction of nickel into a furnace and a ladle. It was shown that after nickel is added, a holding of 14 or 15 min of a boiling bath is sufficient to fully dissolve nickel and distribute it uniformly throughout the molten metal

  6. Black Culture

    Directory of Open Access Journals (Sweden)

    Angela Khristin Brown

    2013-07-01

    Full Text Available The migration of blacks in North America through slavery became united.  The population of blacks past downs a tradition of artist through art to native born citizens. The art tradition involved telling stories to each generation in black families. The black culture elevated by tradition created hope to determine their personal freedom to escape from poverty of enslavement and to establish a way of life through tradition. A way of personal freedoms was through getting a good education that lead to a better foundation and a better way of life. 

  7. Nickel accumulation and nickel oxalate precipitation by Aspergillus niger.

    Science.gov (United States)

    Magyarosy, A; Laidlaw, R D; Kilaas, R; Echer, C; Clark, D S; Keasling, J D

    2002-07-01

    A strain of Aspergillus niger isolated from a metal-contaminated soil was able to grow in the presence of cadmium, chromium, cobalt, copper, and unusually high levels of nickel on solid (8.0 mM) and in liquid (6.5 mM) media. This fungus removed >98% of the nickel from liquid medium after 100 h of growth but did not remove the other metals, as determined by inductively coupled plasma spectroscopy. Experiments with non-growing, live fungal biomass showed that nickel removal was not due to biosorption alone, as little nickel was bound to the biomass at the pH values tested. Furthermore, when the protonophore carbonyl cyanide p-(trifluoremetoxy) phenyl hydrazone (FCCP) was added to the actively growing fungus nickel removal was inhibited, supporting the hypothesis that energy metabolism is essential for metal removal. Analytical electron microscopy of thin-sectioned fungal biomass revealed that metal removed from the broth was localized in the form of small rectangular crystals associated with the cell walls and also inside the cell. X-ray and electron diffraction analysis showed that these crystals were nickel oxalate dihydrate. PMID:12111174

  8. Are black holes totally black?

    CERN Document Server

    Grib, A A

    2014-01-01

    Geodesic completeness needs existence near the horizon of the black hole of "white hole" geodesics coming from the region inside of the horizon. Here we give the classification of all such geodesics with the energies $E/m \\le 1$ for the Schwarzschild and Kerr's black hole. The collisions of particles moving along the "white hole" geodesics with those moving along "black hole" geodesics are considered. Formulas for the increase of the energy of collision in the centre of mass frame are obtained and the possibility of observation of high energy particles arriving from the black hole to the Earth is discussed.

  9. Excessive nickel release from mobile phones--a persistent cause of nickel allergy and dermatitis

    DEFF Research Database (Denmark)

    Jensen, Peter; Johansen, Jeanne D; Zachariae, Claus; Menné, Torkil; Thyssen, Jacob P

    2011-01-01

    Despite the political intention to limit nickel allergy and dermatitis in Europeans, nickel allergy remains frequent. There are several explanations for the persistence of nickel allergy and dermatitis, including the increasing use of mobile phones. Before regulation of nickel release from mobile...... phones, we showed that eight (19.5%) of 41 mobile phones marketed in Denmark between 2003 and 2007 released nickel in concentrations that may result in nickel allergy and dermatitis. In 2009, the EU Nickel Directive was revised to include nickel-releasing mobile phones....

  10. Three dimensional nickel oxides/nickel structure by in situ electro-oxidation of nickel foam as robust electrocatalyst for oxygen evolution reaction

    Science.gov (United States)

    Han, Guan-Qun; Liu, Yan-Ru; Hu, Wen-Hui; Dong, Bin; Li, Xiao; Shang, Xiao; Chai, Yong-Ming; Liu, Yun-Qi; Liu, Chen-Guang

    2015-12-01

    Three dimensional (3D) nickel oxide/nickel (NiOx/Ni) structure has been synthesized through a facile in situ electro-oxidation method. The formation of NiOx through the electro-oxidation process has been proved by SEM and EDX, with some dense black dots appearing on the surface of Ni foam and the molar ratio of O/Ni increasing, which is nearly 7 times larger than the pure Ni foam. The increase in O content indicates the formatted black particles on the surface of Ni foam are composed of NiOx. The electrocatalytic property of the obtained 3D NiOx/Ni structure has been measured and it can be used as a highly active electrocatalyst for oxygen evolution reaction (OER). The overpotential to reach j = 10 mA cm-2 is 0.39 V. And after the long-term I-t measurement, extremely high electrochemical and physical stability are exhibited in the 3D structure, keeping electrochemical activity and morphology the same. The excellent OER properties may be attributed to the 3D structure and the interface effect of NiOx/Ni.

  11. Relationship between nickel allergy and diet

    OpenAIRE

    Sharma Ashimav

    2007-01-01

    Nickel is a ubiquitous trace element and it occurs in soil, water, air and of the biosphere. It is mostly used to manufacture stainless steel. Nickel is the commonest cause of metal allergy. Nickel allergy is a chronic and recurring skin problem; females are affected more commonly than males. Nickel allergy may develop at any age. Once developed, it tends to persist life-long. Nickel is present in most of the dietary items and food is considered to be a major source of nickel exposure for the...

  12. Development of a lightweight nickel electrode

    Science.gov (United States)

    Britton, D. L.; Reid, M. A.

    1984-01-01

    Nickel electrodes made using lightweight plastic plaque are about half the weight of electrodes made from state of the art sintered nickel plaque. This weight reduction would result in a significant improvement in the energy density of batteries using nickel electrodes (nickel hydrogen, nickel cadmium and nickel zinc). These lightweight electrodes are suitably conductive and yield comparable capacities (as high as 0.25 AH/gm (0.048 AH/sq cm)) after formation. These lightweight electrodes also show excellent discharge performance at high rates.

  13. Black market

    International Nuclear Information System (INIS)

    One way for states and subnational groups to acquire material, knowledge and equipment necessary to build a nuclear weapon or device are illegal transactions. These were singular in the past and did not cause the development of a nuclear black market. But all necessary components of a functioning black market exist. Therefore the further spread and extension of the use of nuclear power would enhance the threat of a nuclear black market, if the trade and use of specific nuclear material is not abandoned worldwide. (orig.)

  14. Black tea

    Science.gov (United States)

    ... product containing black tea extract plus green tea extract, asparagus, guarana, kidney bean, and mate along with a combination of kidney bean pods, garcinia, and chromium yeast for 12 weeks does not reduce body weight ...

  15. Nickel isotopes in stellar matter

    Energy Technology Data Exchange (ETDEWEB)

    Nabi, Jameel-Un [GIK Institute of Engineering Sciences and Technology, Faculty of Engineering Sciences, Swabi, Khyber Pakhtunkhwa (Pakistan); The Abdus Salam ICTP, Trieste (Italy)

    2012-06-15

    Isotopes of nickel play a key role during the silicon burning phase up to the presupernova phase of massive stars. Electron capture rates on these nickel isotopes are also important during the phase of core contraction. I present here the microscopic calculation of ground- and excited-states Gamow-Teller (GT) strength distributions for key nickel isotopes. The calculation is performed within the frame-work of the pn-QRPA model. A judicious choice of model parameters, specially of the Gamow-Teller strength parameters and the deformation parameter, resulted in a much improved calculation of GT strength functions. The excited-state GT distributions are much different from the corresponding ground-state distributions resulting in a failure of the Brink's hypothesis. The electron capture and positron decay rates on nickel isotopes are also calculated within the framework of pn-QRPA model relevant to the presupernova evolution of massive stars. The electron capture rates on odd-A isotopes of nickel are shown to have dominant contributions from parent excited states during as early as silicon burning phases. Comparison is being made with the large-scale shell model calculation. During the silicon burning phases of massive stars the electron capture rates on {sup 57,} {sup 59}Ni are around an order of magnitude bigger than shell model rates and can bear consequences for core-collapse simulators. (orig.)

  16. Nickel isotopes in stellar matter

    CERN Document Server

    Nabi, Jameel-Un

    2014-01-01

    Isotopes of nickel play a key role during the silicon burning phase up to the presupernova phase of massive stars. Electron capture rates on these nickel isotopes are also important during the phase of core contraction. I present here the microscopic calculation of ground and excited states Gamow-Teller (GT) strength distributions for key nickel isotopes. The calculation is performed within the frame-work of pn-QRPA model. A judicious choice of model parameters, specially of the Gamow-Teller strength parameters and the deformation parameter, resulted in a much improved calculation of GT strength functions. The excited state GT distributions are much different from the corresponding ground-state distributions resulting in a failure of the Brink's hypothesis. The electron capture and positron decay rates on nickel isotopes are also calculated within the framework of pn-QRPA model relevant to the presupernova evolution of massive stars. The electron capture rates on odd-A isotopes of nickel are shown to have dom...

  17. Didymium compound improves nickel-cadmium cell

    Science.gov (United States)

    1965-01-01

    Nickel electrodes impregnated with an additive solution of didymium hydrate and nitric acid mixed with nickel nitrate increases ampere-hour capacity of cells and does not affect the voltage characteristics.

  18. Nickel hydrogen battery cell storage matrix test

    Science.gov (United States)

    Wheeler, James R.; Dodson, Gary W.

    1993-01-01

    Test were conducted to evaluate post storage performance of nickel hydrogen cells with various design variables, the most significant being nickel precharge versus hydrogen precharge. Test procedures and results are presented in outline and graphic form.

  19. Study of fluoride corrosion of nickel alloys

    Science.gov (United States)

    Gunther, W. H.; Steindler, M. J.

    1969-01-01

    Report contains the results of an investigation of the corrosion resistance of nickel and nickel alloys exposed to fluorine, uranium hexafluoride, and volatile fission product fluorides at high temperatures. Survey of the unclassified literature on the subject is included.

  20. Platinum-ruthenium-nickel fuel cell electrocatalyst

    Science.gov (United States)

    Gorer, Alexander

    2005-07-26

    A catalyst suitable for use in a fuel cell, especially as an anode catalyst, that contains platinum, ruthenium, and nickel, wherein the nickel is at a concentration that is less than about 10 atomic percent.

  1. Pulse reversal plating of nickel alloys

    DEFF Research Database (Denmark)

    Tang, Peter Torben

    2007-01-01

    ), internal stress and material distribution are even more important. With baths based upon nickel chloride, and nickel and cobalt chlorides, pulse reversal plating of both pure nickel and nickel-cobalt alloys has been used to fabricate tools for microinjection moulding. Pulse reversal plating of ternary soft...... magnetic alloys, comprising 45-65%Co, 15-35%Fe and 15-35%Ni, is also reported....

  2. Recent Advances in the Synthesis and Stabilization of Nickel and Nickel Oxide Nanoparticles: A Green Adeptness

    Science.gov (United States)

    Rani, Aneela

    2016-01-01

    Green protocols for the synthesis of nanoparticles have been attracting a lot of attention because they are eco-friendly, rapid, and cost-effective. Nickel and nickel oxide nanoparticles have been synthesized by green routes and characterized for impact of green chemistry on the properties and biological effects of nanoparticles in the last five years. Green synthesis, properties, and applications of nickel and nickel oxide nanoparticles have been reported in the literature. This review summarizes the synthesis of nickel and nickel oxide nanoparticles using different biological systems. This review also provides comparative overview of influence of chemical synthesis and green synthesis on structural properties of nickel and nickel oxide nanoparticles and their biological behavior. It concludes that green methods for synthesis of nickel and nickel oxide nanoparticles are better than chemical synthetic methods.

  3. Nickel may be released from laptop computers

    DEFF Research Database (Denmark)

    Jensen, Peter; Jellesen, Morten Stendahl; Møller, Per;

    2012-01-01

    Consumer nickel sensitization and dermatitis is caused by prolonged or repeated skin exposure to items that release nickel, for example jewellery, belts, buttons, watches, and mobile phones (1–3). We recently described a patient in whom primary nickel contact sensitization and dermatitis develope...

  4. Chemoorganotrophic Bioleaching of Olivine for Nickel Recovery

    OpenAIRE

    Yi Wai Chiang; Santos, Rafael M.; Aldo Van Audenaerde; Annick Monballiu; Tom Van Gerven; Boudewijn Meesschaert

    2014-01-01

    Bioleaching of olivine, a natural nickel-containing magnesium-iron-silicate, was conducted by applying chemoorganotrophic bacteria and fungi. The tested fungus, Aspergillus niger, leached substantially more nickel from olivine than the tested bacterium, Paenibacillus mucilaginosus. Aspergillus niger also outperformed two other fungal species: Humicola grisae and Penicillium chrysogenum. Contrary to traditional acid leaching, the microorganisms leached nickel preferentially over magnesium and ...

  5. Nickel in nails, hair and plasma from nickel-hypersensitive women

    DEFF Research Database (Denmark)

    Gammelgaard, Bente; Veien, Niels

    1990-01-01

    The concentrations of nickel in finger-nails, toe-nails, hair and plasma from 71 nickel-hypersensitive women and 20 non-hypersensitive women were determined. Nickel concentrations in finger-nails were significantly higher than in toe-nails in both the nickel-hypersensitive group and the control...... combination of nails, hair and plasma in the nickel-hypersensitive or in the control group....

  6. Electrochemical Characterisation of Nanocrystalline Nickel

    Directory of Open Access Journals (Sweden)

    Deepika Sachdeva

    2008-07-01

    Full Text Available Nanocry stalline nickel (nc-Ni coatings were produced by pulse electro deposition using Watts bath with sodium citrate and saccharin added as grain refining agents. The electrochemical nature of nc-Ni coatings, evaluated in 1M H2SO4 solution by electrochemical impedance spectroscopy. The corrosion rate of bulk nickel was lower than that of nc-Ni after stabilisation of free corrosion potential.Defence Science Journal, 2008, 58(4, pp.525-530, DOI:http://dx.doi.org/10.14429/dsj.58.1673

  7. Electrochemical Characterisation of Nanocrystalline Nickel

    OpenAIRE

    Deepika Sachdeva; Naveen Gupta; R. Balasubramaniam

    2008-01-01

    Nanocry stalline nickel (nc-Ni) coatings were produced by pulse electro deposition using Watts bath with sodium citrate and saccharin added as grain refining agents. The electrochemical nature of nc-Ni coatings, evaluated in 1M H2SO4 solution by electrochemical impedance spectroscopy. The corrosion rate of bulk nickel was lower than that of nc-Ni after stabilisation of free corrosion potential.Defence Science Journal, 2008, 58(4), pp.525-530, DOI:http://dx.doi.org/10.14429/dsj.58.1673

  8. Nickel cadmium battery expert system

    Science.gov (United States)

    1986-01-01

    The applicability of artificial intelligence methodologies for the automation of energy storage management, in this case, nickel cadmium batteries, is demonstrated. With the Hubble Space Telescope Electrical Power System (HST/EPS) testbed as the application domain, an expert system was developed which incorporates the physical characterization of the EPS, in particular, the nickel cadmium batteries, as well as the human's operational knowledge. The expert system returns not only fault diagnostics but also status and advice along with justifications and explanations in the form of decision support.

  9. Studies on electrochromic properties of nickel oxide thin films prepared by spray pyrolysis technique

    Energy Technology Data Exchange (ETDEWEB)

    Kadam, L.D.; Patil, P.S. [Thin film physics laboratory, Department of Physics, Shivaji University, - 416 004 Kolhapur (India)

    2001-11-01

    Electrochromic nickel oxide thin films were prepared by using a simple and inexpensive spray pyrolysis technique (SPT) onto fluorine-doped tin oxide (FTO) coated glass substrates from nickel chloride solution. Transparent NiO-thin films were obtained at a substrate temperature 350C. The films were cubic NiO with preferred orientation in the (111) direction. Infrared spectroscopy results show presence of free hydroxyl ion and water in nickel oxide thin films. The electrochromic properties of the thin films were studied in an aqueous alkaline electrolyte (0.1M KOH) using cyclic voltammetry (CV), chronoamperometry (CA) and spectrophotometry. The films exhibit anodic electrochromism, changing colour from transparent to black. The colouration efficiency at 630nm was calculated to be 37cm{sup 2}/C.

  10. Nickel isotopes and methanogens

    Science.gov (United States)

    Neubeck, A.; Ivarsson, M.

    2013-12-01

    Methanogens require Ni for their growth and as a consequence the microbial fractionation of Ni isotopes can be used as a biomarker for activity of methanogenic communities1. Anaerobic laboratory experiments was performed using methanogens to investigate methanogenic growth in a modified nutrient media2 with olivine Fo91 (5g/l) added as an additional mineral nutrient source and as the only H2 provider. One of the investigated methanogens showed an increased growth in the experiments with added olivine. There were also a close relationship between the mobilized Ni and the growth of the methanogen. Ni is an element that previously has been neglected in the study of fossilized microorganisms and their interaction with mineral substrates and, thus, there are no records or published data of Ni in association with microfossils. However, we have detected enrichments of Ni in fossilized microorganisms and ichno-fossils, respectively, from three separate locations. Ni is not present in the host rock in any of the samples. Thus, Ni is present in association with fossilized microorganisms from environments and more extensive analysis is required to understand the magnitude, uptake, preservation and fractionation of Ni in microfossils. In order to analyze Ni isotope fractionation from microbe-mineral interaction, we plan to use a high-resolution Laser-Ablation Time-of-Flight Mass Spectrometer (LMS)3. In situ profile ablation will provide detailed and localized data on fractionation patterns between microfossils and their host rock. Also, this technique will allow us to identify the change in Ni isotopic fractionation in rock samples caused by abiotic and biogenic processes in a faster and easier way and with less risk for contamination compared to the wet chemistry analyses of Ni isotopes. 1. Cameron, V., Vance, D., Archer, C. & House, C. H. A biomarker based on the stable isotopes of nickel. Proceedings of the National Academy of Sciences 106, 10944-10948 (2009). 2. Schn

  11. Effect of heat treatment, top coatings and conversion coatings on the corrosion properties of black electroless Ni-P films

    International Nuclear Information System (INIS)

    Electroless black nickel-phosphorus plating is an advanced electroless nickel plating process formulated to deposit a black finish when processed through an oxidizing acid solution. Heat treatment, five types of top organic coating techniques and one conversion coating technique with three different experimental conditions were investigated to stabilize the black film and increase the hardness and corrosion resistance. Morphology and compositions of electroless nickel-phosphorous films with or without heat treatment, with five types of top organic coatings, and with three conversion coatings were compared to examine nickel, phosphorus, oxygen, carbon, silicon and chrome contents on the corrosion resistance of black surfaces by energy dispersive X-ray microanalysis and scanning electron microscope. Corrosion resistance of black electroless nickel-phosphorus coatings with or without heat treatment, with five types of top organic coatings, and with three conversion coatings was investigated by the polarization measurements and the salt spray test in 5% NaCl solution, respectively. HydroLac as the top organic coating from MacDermid showed the excellent corrosion resistance and the black EN film did not lose the black color after 48 h salt spray test. Electrotarnil B process with 0.5 ASD for 1 min stabilized the black Ni-P film immediately and increased the hardness and corrosion performance of the black Ni-P film. The black Ni-P coating with Electroarnil B process passed the 5% NaCl salt spray test for 3000 h in the black color and had a minimal corrosion current 0.8547 μA/cm2 by the polarization measurement.

  12. Rechargeable nickel-zinc batteries

    Science.gov (United States)

    Soltis, D. G.

    1977-01-01

    Device proves superiority in having two and one half to three times the energy content of popular lead-zinc or nickel-cadmium batteries. Application to electric utility vehicles improved acceleration rate and nearly doubled driving range between rechargings. Unit contributes substantially toward realization of practical urban electrical automobiles.

  13. Assaying environmental nickel toxicity using model nematodes

    Science.gov (United States)

    Rudel, David; Douglas, Chandler; Huffnagle, Ian; Besser, John M.; Ingersoll, Christopher G.

    2013-01-01

    Although nickel exposure results in allergic reactions, respiratory conditions, and cancer in humans and rodents, the ramifications of excess nickel in the environment for animal and human health remain largely undescribed. Nickel and other cationic metals travel through waterways and bind to soils and sediments. To evaluate the potential toxic effects of nickel at environmental contaminant levels (8.9-7,600 μg Ni/g dry weight of sediment and 50-800 μg NiCl2/L of water), we conducted assays using two cosmopolitan nematodes, Caenorhabditis elegans and Pristionchus pacificus. We assayed the effects of both sediment-bound and aqueous nickel upon animal growth, developmental survival, lifespan, and fecundity. Uncontaminated sediments were collected from sites in the Midwestern United States and spiked with a range of nickel concentrations. We found that nickel-spiked sediment substantially impairs both survival from larval to adult stages and adult longevity in a concentration-dependent manner. Further, while aqueous nickel showed no adverse effects on either survivorship or longevity, we observed a significant decrease in fecundity, indicating that aqueous nickel could have a negative impact on nematode physiology. Intriguingly, C. elegans and P. pacificus exhibit similar, but not identical, responses to nickel exposure. Moreover, P. pacificus could be tested successfully in sediments inhospitable to C. elegans. Our results add to a growing body of literature documenting the impact of nickel on animal physiology, and suggest that environmental toxicological studies could gain an advantage by widening their repertoire of nematode species.

  14. Method for decontamination of nickel-fluoride-coated nickel containing actinide-metal fluorides

    Science.gov (United States)

    Windt, N.F.; Williams, J.L.

    In one aspect, the invention comprises contacting nickel-fluoride-coated nickel with gaseous ammonia at a temperature effecting nickel-catalyzed dissociation thereof and effecting hydrogen-reduction of the nickel fluoride. The resulting nickel is heated to form a melt and a slag and to effect transfer of actinide metals from the melt into the slag. The melt and slag are then separated. In another aspect, nickel contianing nickel oxide and actinide metals is contacted with ammonia at a temperature effecting nickel-catalyzed dissociation to effect conversion of the nickel oxide to the metal. The resulting nickel is then melted and separated as described. In another aspect nickel-fluoride-coated nickel containing actinide-metal fluorides is contacted with both steam and ammonia. The resulting nickel then is melted and separated as described. The invention is characterized by higher nickel recovery, efficient use of ammonia, a substantial decrease in slag formation and fuming, and a valuable increase in the service life of the furnace liners used for melting.

  15. Chromium, nickel and vanadium mobility in soils derived from fluvioglacial sands

    Energy Technology Data Exchange (ETDEWEB)

    Agnieszka, Jeske, E-mail: agnieszka.jeske@ios.edu.pl [Institute of Environmental Protection-National Research Institute, Krucza 5/11, 00-548, Warsaw (Poland); Warsaw University of Life Sciences, Division of Soil Science, Nowoursynowska 157, Warsaw (Poland); Barbara, Gworek [Institute of Environmental Protection-National Research Institute, Krucza 5/11, 00-548, Warsaw (Poland); Warsaw University of Life Sciences, Division of Soil Science, Nowoursynowska 157, Warsaw (Poland)

    2012-10-30

    Highlights: Black-Right-Pointing-Pointer Mobility of Cr, Ni, V was analysed in rusty soils derived from fluvioglacial sands. Black-Right-Pointing-Pointer The aim was the determination the link between soil constituents and fractions. Black-Right-Pointing-Pointer To determine mobile fractions the Tessier et al. method was used. Black-Right-Pointing-Pointer Metals occurred predominantly in immobile fractions. Black-Right-Pointing-Pointer Potential mobility, bioavailability of mentioned metals is as follows Ni > Cr > V. - Abstract: The presented study was focused on soils developed from fluvioglacial sands from the Puszcza Borecka forest complex. The mobility of chromium, nickel and vanadium was evaluated with regard to litho- and pedogenic factors. The aim of the study was to determine with which soil constituents fractions of heavy metals are bound with particular attention drawn on the mobile fractions (F1 + F2). Heavy metal fractions in the soils were determined using the sequential extraction method of Tessier et al. The purpose of sequential extraction methods to soil samples provides relevant information about possible toxicity when they are discharged into the soil environment. Chromium, nickel, and vanadium occurred predominantly in the fraction bound with iron and manganese oxides and in the residual fraction, thus showed low mobility. With regard to mobility, the elements studied can be arranged as follows: V < Cr < Ni. The content of the mobile fractions depended on the soil texture. The influence of the rusting process on the distribution of the bioavailable fractions was observed in the soil profiles.

  16. Optical modeling of nickel-base alloys oxidized in pressurized water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Clair, A. [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS, Universite de Bourgogne, 9 avenue Alain Savary, BP 47870, 21078 Dijon cedex (France); Foucault, M.; Calonne, O. [Areva ANP, Centre Technique Departement Corrosion-Chimie, 30 Bd de l' industrie, BP 181, 71205 Le Creusot (France); Finot, E., E-mail: Eric.Finot@u-bourgogne.fr [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS, Universite de Bourgogne, 9 avenue Alain Savary, BP 47870, 21078 Dijon cedex (France)

    2012-10-01

    The knowledge of the aging process involved in the primary water of pressurized water reactor entails investigating a mixed growth mechanism in the corrosion of nickel-base alloys. A mixed growth induces an anionic inner oxide and a cationic diffusion parallel to a dissolution-precipitation process forms the outer zone. The in situ monitoring of the oxidation kinetics requires the modeling of the oxide layer stratification with the full knowledge of the optical constants related to each component. Here, we report the dielectric constants of the alloys 600 and 690 measured by spectroscopic ellipsometry and fitted to a Drude-Lorentz model. A robust optical stratification model was determined using focused ion beam cross-section of thin foils examined by transmission electron microscopy. Dielectric constants of the inner oxide layer depleted in chromium were assimilated to those of the nickel thin film. The optical constants of both the spinels and extern layer were determined. - Highlights: Black-Right-Pointing-Pointer Spectroscopic ellipsometry of Ni-base alloy oxidation in pressurized water reactor Black-Right-Pointing-Pointer Measurements of the dielectric constants of the alloys Black-Right-Pointing-Pointer Optical simulation of the mixed oxidation process using a three stack model Black-Right-Pointing-Pointer Scattered crystallites cationic outer layer; linear Ni-gradient bottom layer Black-Right-Pointing-Pointer Determination of the refractive index of the spinel and the Cr{sub 2}O{sub 3} layers.

  17. Fischer Black

    OpenAIRE

    Robert C. Merton; Myron S. Scholes

    2013-01-01

    ReprintThis article was originally published by Wiley for the American Finance Association (Merton RC, Scholes MS. 1995. Fischer Black. J. Finance 50(5):1359–70). It is reprinted with permission from John Wiley and Sons © 1995. Reference formatting was updated to facilitate linking.

  18. Nickel nanofibers synthesized by the electrospinning method

    International Nuclear Information System (INIS)

    Highlights: ► The nickel nanofibers have been obtained by electrospinning method. ► The nickel nanofibers had rough surface which was consisted of mass nanoparticles. ► The average diameter of nickel nanofibers is about 135 nm and high degree of crystallization. ► The Hc, Ms, and Mr were estimated to be 185 Oe, 51.9 and 16.9 emu/g respectively. - Abstract: In this paper, nickel nanofibers were prepared by electrospinning polyvinyl alcohol/nickel nitrate precursor solution followed by high temperature calcination in air and deoxidation in hydrogen atmosphere. The thermal stability of the as-electrospun PVA/Ni(NO3)2 composite nanofibers were characterized by TG–DSC. The morphologies and structures of the as-prepared samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field-emission scanning electronmicroscope (FE-SEM) and field-emission transmission electron microscopy (FE-TEM). The hysteresis loops (M–H loops) were measured by Physical Property Measurement System (PPMS). The results indicate that: the PVA and the nickel nitrate were almost completely decomposed at 460 °C and the products were pure nickel nanofibers with face-centered cubic (fcc) structure. Furthermore, the as-prepared nickel nanofibers had a continuous structure with rough surface and high degree of crystallization. The average diameter of nickel nanofibers was about 135 nm. The nanofibers showed a stronger coercivity of 185 Oe than value of bulk nickel

  19. Nickel nanofibers synthesized by the electrospinning method

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Yi [School of Materials Science and Engineering, Hefei University of Technology, Anhui 230000 (China); Zhang, Xuebin, E-mail: zzhhxxbb@126.com [School of Materials Science and Engineering, Hefei University of Technology, Anhui 230000 (China); Zhu, Yajun; Li, Bin; Wang, Yang; Zhang, Jingcheng; Feng, Yi [School of Materials Science and Engineering, Hefei University of Technology, Anhui 230000 (China)

    2013-07-15

    Highlights: ► The nickel nanofibers have been obtained by electrospinning method. ► The nickel nanofibers had rough surface which was consisted of mass nanoparticles. ► The average diameter of nickel nanofibers is about 135 nm and high degree of crystallization. ► The Hc, Ms, and Mr were estimated to be 185 Oe, 51.9 and 16.9 emu/g respectively. - Abstract: In this paper, nickel nanofibers were prepared by electrospinning polyvinyl alcohol/nickel nitrate precursor solution followed by high temperature calcination in air and deoxidation in hydrogen atmosphere. The thermal stability of the as-electrospun PVA/Ni(NO{sub 3}){sub 2} composite nanofibers were characterized by TG–DSC. The morphologies and structures of the as-prepared samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field-emission scanning electronmicroscope (FE-SEM) and field-emission transmission electron microscopy (FE-TEM). The hysteresis loops (M–H loops) were measured by Physical Property Measurement System (PPMS). The results indicate that: the PVA and the nickel nitrate were almost completely decomposed at 460 °C and the products were pure nickel nanofibers with face-centered cubic (fcc) structure. Furthermore, the as-prepared nickel nanofibers had a continuous structure with rough surface and high degree of crystallization. The average diameter of nickel nanofibers was about 135 nm. The nanofibers showed a stronger coercivity of 185 Oe than value of bulk nickel.

  20. Market for nickel-cadmium batteries

    Science.gov (United States)

    Putois, F.

    Besides the lead/acid battery market, which has seen a tremendous development linked with the car industry, the alkaline rechargeable battery market has also been expanded for more than twenty years, especially in the field of portable applications with nickel-cadmium batteries. Today, nickel-cadmium batteries have to face newcomers on the market, such as nickel-metal hydride, which is another alkaline couple, and rechargeable lithium batteries; these new battery systems have better performances in some areas. This work illustrates the status of the market for nickel-cadmium batteries and their applications. Also, for two major applications—the cordless tool and the electric vehicles—the competitive situation of nickel-cadmium batteries; facing new systems such as nickel-metal hydride and lithium ion cells are discussed.

  1. Recent Advances in the Synthesis and Stabilization of Nickel and Nickel Oxide Nanoparticles: A Green Adeptness

    OpenAIRE

    Imran Din, Muhammad; Rani, Aneela

    2016-01-01

    Green protocols for the synthesis of nanoparticles have been attracting a lot of attention because they are eco-friendly, rapid, and cost-effective. Nickel and nickel oxide nanoparticles have been synthesized by green routes and characterized for impact of green chemistry on the properties and biological effects of nanoparticles in the last five years. Green synthesis, properties, and applications of nickel and nickel oxide nanoparticles have been reported in the literature. This review summa...

  2. Linear Genetic Programming for Prediction of Nickel Recovery from Spent Nickel Catalyst

    OpenAIRE

    Mon E. Ossman; Walaa Sheta; Y. Eltaweel

    2010-01-01

    Problem statement: In this study Linear Genetic Programming (LGP) and statistical regression are used in predicting Current Efficiency (CE) of Electro deposition cell used for recovery of nickel from spent nickel catalyst. Approach: The Nickel electro deposition from spent catalyst leachate solutions was studied to determine the effect of the operative conditions such as nickel concentration, temperature, current density and time on the CE of the unit cell. Results: For this purpose, LGP and ...

  3. The EU Nickel Directive revisited--future steps towards better protection against nickel allergy

    DEFF Research Database (Denmark)

    Thyssen, Jacob P; Uter, Wolfgang; McFadden, John;

    2011-01-01

    the EU Nickel Directive. Despite this, the EU Nickel Directive part 2 was expected to work as an operational limit that would sufficiently protect European consumers against nickel allergy and dermatitis. This review presents the accumulation of epidemiological studies that evaluated the possible...

  4. Investigation of sugar sulfur carrier in nickel

    International Nuclear Information System (INIS)

    For the purposes of galvanotechnics it is necessary to have nickel which is easely subjected to the anode dissolving (the so called depolarized nickel). In the industry, nickel of such a quality is produced by the method of electrolytic sedimentation from the nickel solution in the presence of sulfur carriers, usually in the presence of saccharin. To study behaviour of saccharin in the process of electrolysis, investigations of saccharin labelled by sulfur-35 have been done. These investigations have permitted to determine the type and quantity of products of decomposition formed, as well as to determine possibilities for rising the quantity of introducer sulfur due to the variants of technological process

  5. Preparation of Nickel Materials with Fractal Structure

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A way of manufacturing nickel material with fractal structure has been studied. Some algae with natural fractalstructure were used as the basic substrates. The nickel was coated on the substrates by both electroless depositionand electrodeposition. After elimination of the foundational algae by erosion, dissolution etc, the pure nickel materialswith fractal structure were obtained. At last, the specific surface area was analyzed by BET analyses and the fractaldimension of the nickel material was calculated by means of box-counting technique. The comparison of fractaldimension between Ni structure and natural algae was also given.

  6. Nickel-induced cytokine production from mononuclear cells in nickel-sensitive individuals and controls. Cytokine profiles in nickel-sensitive individuals with nickel allergy-related hand eczema before and after nickel challenge

    DEFF Research Database (Denmark)

    Borg, L; Christensen, J M; Kristiansen, J;

    2000-01-01

    Exposure to nickel is a major cause of allergic contact dermatitis which is considered to be an inflammatory response induced by antigen-specific T cells. Here we describe the in vitro analysis of the nickel-specific T-cell-derived cytokine response of peripheral blood mononuclear cells from 35...... somewhat of a surprise, since previous studies have suggested a Th1 response in nickel-mediated allergic contact dermatitis. Subsequently, the nickel-allergic individuals were randomized to experimental exposure to nickel or vehicle in a double-blind design. A daily 10-min exposure of one finger to 10 ppm...... nickel solution for 1 week followed by 100 ppm for an additional week evoked a clinical response of hand eczema in the nickel-exposed group. Blood samples were drawn on days 7 and 14 after the start of this exposure to occupationally relevant concentrations of nickel. No statistically significant...

  7. A comprehensive study of structural and magnetic properties of sputter deposited nickel-silica thin films

    Energy Technology Data Exchange (ETDEWEB)

    Walia, Rajan [Nanoscience Laboratory, Institute Instrumentation Centre, Indian Institute of Technology Roorkee, Roorkee 247667 (India); Pivin, J.C. [Centre Spectrometrie Nucleaire et de Spectrometrie de Masse (CSNSM) IN2P3-CNRS, Batiment 108, 91405 Orsay Campus (France); Chawla, A.K. [Nanoscience Laboratory, Institute Instrumentation Centre, Indian Institute of Technology Roorkee, Roorkee 247667 (India); Jayaganthan, R.; Gautam, Y.K. [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Roorkee, Roorkee 247667 (India); Chandra, Ramesh, E-mail: ramesfic@iitr.ernet.in [Nanoscience Laboratory, Institute Instrumentation Centre, Indian Institute of Technology Roorkee, Roorkee 247667 (India)

    2012-08-01

    Highlights: Black-Right-Pointing-Pointer Ni nanoparticles embedded in silica matrix have been synthesized by DC/RF sputtering. Black-Right-Pointing-Pointer Magnetic properties of nickel nanoparticles have been found size dependent strongly. Black-Right-Pointing-Pointer Ni nanoparticles are found to be superparamagnetic {<=}6 nm. Black-Right-Pointing-Pointer Coercivity decreases with increase in particle size and concentration. - Abstract: The present work reports the formation of Ni nanoparticles inside the SiO{sub 2} matrix and deals with the influence of Ni concentration on structural and magnetic properties of Ni-SiO{sub 2} nanocomposite thin films. The films with varying Ni concentration (20-55 at% measured by Rutherford back scattering spectroscopy) were deposited using DC/RF magnetron co-sputtering. TEM and XRD analysis reveal the formation of FCC Ni nanoparticles in all the samples. The particle size varies from 3 to 10 nm as a function of Ni concentration. The surface roughness of the films is also found to increase with increase in nickel concentration. Magnetic measurements show that the Ni nanoparticles behave as superparamagnets when their size is {<=}6 nm, in spite of their large volume fractions. The results show that the magnetic properties of the nanoparticles can be controlled by their size and Ni concentration in the samples.

  8. Synthesis and electrochemical characterization of stabilized nickel nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Dominguez-Crespo, M.A.; Ramirez-Meneses, E.; Torres Huerta, A.M. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, CICATA-IPN Unidad Altamira, Carretera Tampico-Puerto Industrial, C.P. 89600 Altamira, Tamaulipas (Mexico); Montiel-Palma, V. [Centro de Investigaciones Quimicas, Universidad Autonoma del Estado de Morelos, Av. Universidad 1001, Colonia Chamilpa, C.P.62201 Cuernavaca, Morelos (Mexico); Dorantes Rosales, H. [Departamento de Metalurgia, Escuela Superior de Ingenieria Quimica e Industrias Extractivas - IPN, C.P. 07300, D.F. (Mexico)

    2009-02-15

    Nickel stabilized nanoparticles produced by an organometallic approach (Chaudret's method) starting from the complex Ni(1,5-COD){sub 2} were used as electrode materials for hydrogen evolution in NaOH at two temperatures (298 and 323 K). The synthesis of the nickel nanoparticles was performed in the presence of two different stabilizers, 1,3-diaminopropane (DAP) and anthranilic acid (AA), by varying the molar ratios (1:1, 1:2 and 1:5 metal:ligand) in order to evaluate their influence on the shape, dispersion, size and electrocatalytic activity of the metallic particles. The presence of an appropriate amount of stabilizer is an effective alternative to the synthesis of small monodispersed metal nanoparticles with diameters around 5 and 8 nm for DAP and AA, respectively. The results are discussed in terms of morphology and the surface state of the nanoparticles. The importance of developing a well-controlled synthetic method which results in higher performances of the resulting nanoparticles is highlighted. Herein we found that the performance with respect to the HER of the Ni electrodes dispersed on a carbon black Vulcan substrate is active and comparable to that reported in the literature for the state-of-the-art electrocatalysts. Appreciable cathodic current densities of {proportional_to}240 mA cm{sup -2} were measured with highly dispersed nickel particles (Ni-5{sub DAP}). This work demonstrates that the aforementioned method can be extended to the preparation of highly active stabilized metal particles without inhibiting the electron transfer for the HER reaction, and it could also be applied to the synthesis of bimetallic nanoparticles. (author)

  9. Nanoscale nickel oxide/nickel heterostructures for active hydrogen evolution electrocatalysis.

    Science.gov (United States)

    Gong, Ming; Zhou, Wu; Tsai, Mon-Che; Zhou, Jigang; Guan, Mingyun; Lin, Meng-Chang; Zhang, Bo; Hu, Yongfeng; Wang, Di-Yan; Yang, Jiang; Pennycook, Stephen J; Hwang, Bing-Joe; Dai, Hongjie

    2014-01-01

    Active, stable and cost-effective electrocatalysts are a key to water splitting for hydrogen production through electrolysis or photoelectrochemistry. Here we report nanoscale nickel oxide/nickel heterostructures formed on carbon nanotube sidewalls as highly effective electrocatalysts for hydrogen evolution reaction with activity similar to platinum. Partially reduced nickel interfaced with nickel oxide results from thermal decomposition of nickel hydroxide precursors bonded to carbon nanotube sidewalls. The metal ion-carbon nanotube interactions impede complete reduction and Ostwald ripening of nickel species into the less hydrogen evolution reaction active pure nickel phase. A water electrolyzer that achieves ~20 mA cm(-2) at a voltage of 1.5 V, and which may be operated by a single-cell alkaline battery, is fabricated using cheap, non-precious metal-based electrocatalysts. PMID:25146255

  10. Reactive spraying of nickel-aluminide coatings

    Science.gov (United States)

    Deevi, S. C.; Sikka, V. K.; Swindeman, C. J.; Seals, R. D.

    1997-09-01

    Reactive spraying of nickel aluminides was accomplished via reaction synthesis techniques in which nickel and aluminum powders were fed through a direct- current plasma torch onto carbon steel substrates. The as- sprayed coatings obtained by reactive spraying were characterized by x- ray diffraction and microscopic techniques. Reactive spraying of nickel and aluminum resulted in coatings consisting of Ni, Al, Ni 3Al, NiAl3, Ni5Al3, NiAl, and Al2O3, depending on the experimental conditions. Nickel aluminide phases observed in plasma spray depositions were compared with the phases obtained by combustion synthesis techniques, and the formation of phases in reactive spraying was attributed to the exothermic reaction between splats of aluminum and nickel. Primary and secondary reactions leading to the formation of nickel aluminides were also examined. The splat thickness and the reaction layer suppressed the formation of desired equilibrium phases such as Ni3Al and NiAl. As- sprayed coatings were annealed to enhance the diffusional reactions between the product phases and aluminum and nickel. Coatings obtained by reactive spraying of elemental powders were compared with as- sprayed and annealed coatings obtained with a bond coat material in which nickel was deposited onto aluminum particles.

  11. Coin exposure may cause allergic nickel dermatitis

    DEFF Research Database (Denmark)

    Thyssen, Jacob P; Gawkrodger, David J; White, Ian R;

    2012-01-01

    Nickel is used in coins because the metal has beneficial properties, including price, colour, weight, and corrosion resistance, and also because it is easy to stamp. It has often been claimed that the duration of skin contact with coins is too short to cause nickel release and dermatitis. However...

  12. Aluminium and nickel in human albumin solutions

    DEFF Research Database (Denmark)

    Gammelgaard, Bente; Sandberg, E

    1989-01-01

    Five different brands of commercially available human albumin solutions for infusion were analysed for their aluminium and nickel contents by atomic absorption spectrometry. The aluminium concentrations ranged from 12 micrograms/l to 1109 micrograms/l and the nickel concentrations ranged from 17...

  13. Lead-nickel electrochemical batteries

    CERN Document Server

    Glaize, Christian

    2012-01-01

    The lead-acid accumulator was introduced in the middle of the 19th Century, the diverse variants of nickel accumulators between the beginning and the end of the 20th Century. Although old, these technologies are always very present on numerous markets. Unfortunately they are still not used in optimal conditions, often because of the misunderstanding of the internal electrochemical phenomena.This book will show that batteries are complex systems, made commercially available thanks to considerable amounts of scientific research, empiricism and practical knowledge. However, the design of

  14. Modified nickel electrodes: a review

    International Nuclear Information System (INIS)

    Catalysts in the form of electrode surfaces offer the added dimension of the electrode potential which can be used to manage the catalyst reactivity and in some cases selectivity. The catalytic effect of nickel oxyhydroxide for the electrochemical determination of organics in alkaline media is very common. This has also received substantial thought because of the application of Ni in rechargeable alkaline batteries. This subject matter has been reviewed from different views before. The present review depicts the role of additives and the modifiers towards the enhancement of electro catalytic properties of electrode surface. (author)

  15. Structure investigations of electrodeposited nickel

    International Nuclear Information System (INIS)

    Nickel, electrodeposited under different conditions and yielding different values of stress, was investigated by positron annihilation (lifetime and Doppler-broadening), Moessbauer effect and X-ray diffraction measurements. Two-component positron lifetime spectra were obtained. The first component is thought to result from bulk annihilation and trapping at single trapping centres (TC). Estimations of TC-concentrations are obtained by means of the trapping model. The second one possibly denotes annihilation at voids, the number of which is dependent on the stress in the deposit. Results of Doppler-broadening measurements support this interpretation. The Moessbauer results show differences in the magnetic orientation in the three samples examined. (orig.)

  16. Structure investigations of electrodeposited nickel

    International Nuclear Information System (INIS)

    Electrodeposited nickel samples were investigated by positron annihilation (lifetime and Doppler-broadening), Moessbauer effect and X-ray diffraction measurements. Two-component positron lifetime spectra were obtained. The first component is thought to result from bulk annihilation and trapping at single trapping centres (TC), their concentrations are obtained from the trapping model. The second one possibly denotes annihilation at voids, the number of which is dependent on the stress in the deposit. The Moessbauer results show differences in the magnetic orientation in the three samples examined. (author)

  17. Compressibility of Nickel Nanoparticle Chain

    Institute of Scientific and Technical Information of China (English)

    LI Xiao-Dong; TANG Ling-Yun; LI Yan-Chun; LIU Jing

    2007-01-01

    We perform the high-pressure energy dispersive x-ray diffraction experiments of nickel nanoparticle chain using a synchrotron source under quasi-hydrostatic compression up to 44.7GPa. There is no phase transition over the pressure range. The bulk modulus Kg, the first pressure derivative of bulk modulus K'0 and the volume Vo are calculated from the pressure-volume data using the Birch-Murnaghan equation of state. A decrease of compressibility is observed, in agreement with the Hall-Petch effect.

  18. Nickel-hydrogen separator development

    Science.gov (United States)

    Gonzalez-Sanabria, O. D.

    1986-01-01

    The separator technology is a critical element in the nickel-hydrogen (Ni-H2) systems. Previous research and development work carried out at NASA Lewis Research Center has determined that separators made from zirconium oxide (ZrO2) and potassium titanate (PKT) fibers will function satisfactorily in Ni-H2 cells without exhibiting the problems associated with the asbestos separators. A program has been established to transfer the separator technology into a commercial production line. A detailed plan of this program will be presented and the preliminary results will be discussed.

  19. Satellite spectra of heliumlike nickel

    International Nuclear Information System (INIS)

    Spectra of heliumlike nickel, NiXXVII, have been observed from Tokamak Fusion Test Reactor (TFTR) plasmas with a high resolution crystal spectrometer. The experimental arrangement permits simultaneous observation of the heliumlike resonance line, the intercombination and forbidden lines, and all the associated satellites due to transitions 1s2nl - 1s2l'nl'' with N ≥ 2. Relative wavelengths and line intensities can thus be determined very accurately. The observed spectral data are in good agreement with results from the present Hartree-Fock-Slater atomic model calculations and predictions from the Z-expansion method

  20. Radionic nonuniform black strings

    Science.gov (United States)

    Tamaki, Takashi; Kanno, Sugumi; Soda, Jiro

    2004-01-01

    Nonuniform black strings in the two-brane system are investigated using the effective action approach. It is shown that the radion acts as a nontrivial hair of the black strings. From the brane point of view, the black string appears as the deformed dilatonic black hole which becomes a dilatonic black hole in the single brane limit and reduces to the Reissner-Nordström black hole in the close limit of two-branes. The stability of solutions is demonstrated using catastrophe theory. From the bulk point of view, the black strings are proved to be nonuniform. Nevertheless, the zeroth law of black hole thermodynamics still holds.

  1. Stabilization of nickel-laden sludge by a high-temperature NiCr{sub 2}O{sub 4} synthesis process

    Energy Technology Data Exchange (ETDEWEB)

    Li, Nien-Hsun; Chen, Yen-Hsin [Graduate Institute of Environmental Engineering, National Taiwan University, 71, Chou-Shan Rd., Taipei 106, Taiwan, ROC (China); Hu, Ching-Yao [School of Public Health, Taipei Medical University, 250 Wu-Xing Street, Taipei 110, Taiwan, ROC (China); Hsieh, Ching-Hong [Graduate Institute of Environmental Engineering, National Taiwan University, 71, Chou-Shan Rd., Taipei 106, Taiwan, ROC (China); Lo, Shang-Lien, E-mail: sllo@ntu.edu.tw [Graduate Institute of Environmental Engineering, National Taiwan University, 71, Chou-Shan Rd., Taipei 106, Taiwan, ROC (China)

    2011-12-30

    Highlights: Black-Right-Pointing-Pointer The nickel-laden sludge was transformed into NiCr{sub 2}O{sub 4} spinel by thermal treatment. Black-Right-Pointing-Pointer Leaching concentration of both nickel and chromium decreased because of the formation of NiCr{sub 2}O{sub 4}. Black-Right-Pointing-Pointer The existence of salt in sludge would disturb the formation of NiCr{sub 2}O{sub 4}. Black-Right-Pointing-Pointer The Cr/Ni molar >2 was contributive to the stabilization efficiency of heavy metal. - Abstract: The feasibility of stabilizing nickel-laden sludge by a high-temperature NiCr{sub 2}O{sub 4} synthesis process was investigated with different sintering temperatures, salt contents, molar ratios, and reaction atmospheres. The crystalline phases of species were investigated by using an X-ray diffraction, and the surface characteristics of particles were observed by scanning electron microscopy. The leaching behavior of the stabilized sludge was evaluated by Toxicity Characteristic Leaching Procedure (TCLP) test. The results indicated that NiCr{sub 2}O{sub 4} was formed at around 800 Degree-Sign C by transforming NiO and Cr{sub 2}O{sub 3} into a spinel structure. Leaching concentrations of both nickel and chromium decreased with an increase in the sintering temperature. The existence of salt in the sludge disturbed the formation of spinel, but a moderate salt content contributed to stabilization efficiency. A Cr/Ni molar ratio >2 also contributed to the stabilization efficiency of heavy metals after the thermal process. NiCr{sub 2}O{sub 4} was transformed from simulated sludge under both an N{sub 2} and air atmosphere. The sintering strategy designed for nickel-laden sludge was proven to be beneficial in stabilizing nickel and chromium.

  2. Reclaim nickel and remove organics from the spent electroless nickel-plating bath by electrolysis

    Institute of Scientific and Technical Information of China (English)

    YU Xiu-juan; SHEN Jin; MENG Xian-lin; LI Shu-qin; YAN Lei; ZHOU Ding

    2006-01-01

    Typical wastes from nickel plating operations include excess drag-out solution. An electrochemical approach was made to recover the nickel and remove the organic pollutants from the spent electroless nickelplating bath. An electrolyte cell which was constructed by the cathode of porous nickel foam and the anode of Ti/RuO2 was used. During electrolysis, the nickel ion was electrodeposited at the cathode and the oxidation of the organics in the bath was conducted at the anode. The current ( i), time ( t), temperature (T) and pH of the solution affected the recovery efficiency of nickel with constant potential electrolysis. With the optimum experimental conditions of pH = 7. 6, i = 0.45 A, T = 65℃ and t = 2 h, the concentration of nickel ion was reduced from 2. 09 g/L to 0. 053 g/L and the recovery rate of nickel, the current efficiency and the consumed energy were 97.5%, 17.1%, 12.2 kWh/kg Ni, respectively. Meanwhile, total organic carbon (TOC) of the bath was reduced from 5 800 mg/L to 152. 5 mg/L and the removal efficiency of TOC was 97.3%. The recovery rate of nickel could keep to about 97% when electrodeposit was used to recover nickel for 40 hours in a laboratory batch reactor containing the spent bath. Dull nickel containing phosphorus was obtained on the cathode.

  3. Role of nickel in membrane-bound hydrogenase and nickel metabolism in Rhizobium japonicum

    International Nuclear Information System (INIS)

    The membrane-bound hydrogenase of Rhizobium japonicum requires nickel for activity. Radioactive 63Ni co-migrates with hydrogenase activity in native gel systems and co-elutes with purified hydrogenase form an affinity matrix column. A simplified scheme for the purification of hydrogenase has been developed and constitutes the first report of the aerobic purification of this enzyme from R. japonicum. The aerobic purification utilizes the general affinity matrix. Reactive Red 120-agarose and results in higher specific activity and yield of enzyme than previously reported. The stability of aerobically purified hydrogenase to oxygen is substantially greater than that reported for anaerobically isolated enzyme. Reduction of the aerobically purified enzyme in the presence of oxygen, however, results in the rapid loss of activity. R. japonicum cells accumulate nickel during heterotrophic growth and as non-growing cells. The hydrogenase constitutive mutant SR470 accumulates substantially greater amounts of nickel under both conditions. Kinetic studies indicate that the nickel uptake system in the hydrogenase constitutive mutant SR470 is upregulated relative to SRwt cells. The uptake system is specific for nickel, although a 10-fold excess (relative to nickel) of copper or zinc inhibits nickel uptake. The nickel uptake system appears to require energy. Under nickel-free conditions hydrogenase protein is not synthesized as determined by cross-reactivity with antibodies directed against hydrogenase, indicating that nickel regulates the formation of the enzyme as well as being a constituent of the active protein

  4. Black Silicon Solar Cells with Black Ribbons

    DEFF Research Database (Denmark)

    Davidsen, Rasmus Schmidt; Tang, Peter Torben; Mizushima, Io;

    2016-01-01

    We present the combination of mask-less reactive ion etch (RIE) texturing and blackened interconnecting ribbons as a method for obtaining all-black solar panels, while using conventional, front-contacted solar cells. Black silicon made by mask-less reactive ion etching has total, average...... range 15.7-16.3%. The KOH-textured reference cell had an efficiency of 17.9%. The combination of black Si and black interconnecting ribbons may result in aesthetic, all-black panels based on conventional, front-contacted silicon solar cells....... reflectance below 0.5% across a 156x156 mm2 silicon (Si) wafer. Black interconnecting ribbons were realized by oxidizing copper resulting in reflectance below 3% in the visible wavelength range. Screen-printed Si solar cells were realized on 156x156 mm2 black Si substrates with resulting efficiencies in the...

  5. Noncommutative black holes

    International Nuclear Information System (INIS)

    We study noncommutative black holes, by using a diffeomorphism between the Schwarzschild black hole and the Kantowski-Sachs cosmological model, which is generalized to noncommutative minisuperspace. Through the use of the Feynman-Hibbs procedure we are able to study the thermodynamics of the black hole, in particular, we calculate Hawking's temperature and entropy for the 'noncommutative' Schwarzschild black hole

  6. Black Entrepreneurship in America.

    Science.gov (United States)

    Green, Shelley; Pryde, Paul

    The economic condition of black Americans is discussed, proceeding from the assumption that black economic progress does not depend on a renewed struggle for unobtained civil rights, but rather on the creative response of black Americans to economic opportunity and problems. In the long run, black economic development must rely on the…

  7. Chemical form analysis method of particulate nickel compounds

    International Nuclear Information System (INIS)

    Chemical form of nickel is metallic nickel, nickel oxide and nickel ferrite in the PWR primary chemistry condition. The distribution of chemical form depends on Ni/Fe ratio and chemistry condition, especially dissolved hydrogen concentration. Nickel is parent element of Co-58 and the chemical form is important for Co-58 generation. A method of chemical form analysis of nickel has been developed. This method uses the difference in dissolution characteristics of nickel compounds. Metallic nickel and others are separated by nitric acid, and others are divided to nickel oxide and nickel ferrite by oxalic acid. Some cruds in the primary coolant of a PWR were analyzed by using this method. The method is not complex and available at chemical laboratory in a nuclear power plant. (author)

  8. Nickel and titanium nanoboride composite coating

    Science.gov (United States)

    Efimova, K. A.; Galevsky, G. V.; Rudneva, V. V.; Kozyrev, N. A.; Orshanskaya, E. G.

    2015-09-01

    Electrodeposition conditions, structural-physical and mechanical properties (microhardness, cohesion with a base, wear resistance, corrosion currents) of electroplated composite coatings on the base of nickel with nano and micro-powders of titanium boride are investigated. It has been found out that electro-crystallization of nickel with boride nanoparticles is the cause of coating formation with structural fragments of small sizes, low porosity and improved physical and mechanical properties. Titanium nano-boride is a component of composite coating, as well as an effective modifier of nickel matrix. Nano-boride of the electrolyte improves efficiency of the latter due to increased permissible upper limit of the cathodic current density.

  9. Determination of electroless deposition by chemical nickeling

    Directory of Open Access Journals (Sweden)

    M. Badida

    2013-07-01

    Full Text Available Increasing of technical level and reliability of machine products in compliance with the economical and ecological terms belongs to the main trends of the industrial development. During the utilisation of these products there arise their each other contacts and the interaction with the environment. That is the reason for their surface degradation by wear effect, corrosion and other influences. The chemical nickel-plating allows autocatalytic deposition of nickel from water solutions in the form of coherent, technically very profitable coating without usage of external source of electric current. The research was aimed at evaluating the surface changes after chemical nickel-plating at various changes of technological parameters.

  10. Impurity diffusion of niobium in nickel

    International Nuclear Information System (INIS)

    Impurity diffusion of niobium in nickel has been studied employing sandwich type diffusion couples between pure nickel (99.99%) and Ni-4.6 at % Nb alloy, in the temperature range of 1200 to 1500 K. The concentration penetration profiles across the diffusion zone have been established by using electron probe micro analyser (EPMA). The chemical diffusion coefficients have been evaluated by employing Hall's analytical solution to Fick's law. The concentration dependence of these diffusion coefficients has been established and impurity diffusion coefficient of niobium in nickel DNb has been evaluated by extrapolating these values to zero mole fraction of niobium. (author). 11 refs., 2 figs

  11. Microwave dielectric properties of nanostructured nickel ferrite

    Indian Academy of Sciences (India)

    John Jacob; M Abdul Khadar; Anil Lonappan; K T Mathew

    2008-11-01

    Nickel ferrite is one of the important ferrites used in microwave devices. In the present work, we have synthesized nanoparticles of nickel ferrite using chemical precipitation technique. The crystal structure and grain size of the particles are studied using XRD. The microwave dielectric properties of nanostructured nickel ferrite samples of three different average grain sizes and those of two sintered samples were studied. The parameters like dielectric constant, dielectric loss and heating coefficient of the nanoparticles samples are studied in the frequency range from 2.4 to 4 GHz. The values of these parameters are compared with those of sintered pellets of the same samples. All these parameters show size dependent variations.

  12. Nickel-free austenitic stainless steels for medical applications

    OpenAIRE

    Ke Yang and Yibin Ren

    2010-01-01

    The adverse effects of nickel ions being released into the human body have prompted the development of high-nitrogen nickel-free austenitic stainless steels for medical applications. Nitrogen not only replaces nickel for austenitic structure stability but also much improves steel properties. Here we review the harmful effects associated with nickel in medical stainless steels, the advantages of nitrogen in stainless steels, and emphatically, the development of high-nitrogen nickel-free stainl...

  13. Design of a neutral three-dimensional electro-Fenton system with foam nickel as particle electrodes for wastewater treatment

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Wei [Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079 (China); Ai, Zhihui, E-mail: jennifer.ai@mail.ccnu.edu.cn [Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079 (China); Zhang, Lizhi [Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079 (China)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer Remove RhB by a novel 3D-E-Fenton system using foam nickel as particle electrodes. Black-Right-Pointing-Pointer The 3D-E-Fenton system exhibit much higher RhB removal efficiency than the counterpart 3D-E and E-Fenton system. Black-Right-Pointing-Pointer Foam nickel as a particle electrode displays good oxygen reduction activity. Black-Right-Pointing-Pointer The performance of RhB removal was optimized by some operating parameters and the optimization pH was the neutral. - Abstract: In this work, we demonstrate a novel three-dimensional electro-Fenton system (3D-E-Fenton) for wastewater treatment with foam nickel, activated carbon fiber and Ti/RuO{sub 2}-IrO{sub 2} as the particle electrodes, the cathode, and the anode respectively. This 3D-E-Fenton system could exhibit much higher rhodamine B removal efficiency (99%) than the counterpart three-dimensional electrochemical system (33%) and E-Fenton system (19%) at neutral pH in 30 min. The degradation efficiency enhancement was attributed to much more hydroxyl radicals generated in the 3D-E-Fenton system because foam nickel particle electrodes could activate molecular oxygen to produce {center_dot}O{sub 2}{sup -} via a single-electron transfer pathway to subsequently generate more H{sub 2}O{sub 2} and hydroxyl radicals. This is the first observation of molecular oxygen activation over the particle electrodes in the three-dimensional electrochemical system. These interesting findings could provide some new insight on the development of high efficient E-Fenton system for wastewater treatment at neutral pH.

  14. Absorption and retention of nickel from drinking water in relation to food intake and nickel sensitivity

    DEFF Research Database (Denmark)

    Nielsen, G D; Søderberg, U; Jørgensen, Poul Jørgen;

    1999-01-01

    Two studies were performed to examine the influence of fasting and food intake on the absorption and retention of nickel added to drinking water and to determine if nickel sensitization played any role in this regard. First, eight nonallergic male volunteers fasted overnight before being given......-related difference in gastric emptying rates may play a role. Thus, food intake and gastric emptying are of substantial significance for the bioavailability of nickel from aqueous solutions....

  15. Self-interstitials in nickel

    International Nuclear Information System (INIS)

    The self-diffusion coefficient D of nickel was determined after electron irradiation in the temperature range between 150 and 5650C. For irradiation doses below 1018 elect./cm2 a straight line plotting ln D versus 1/T and a square root dependence between the diffusion coefficient and the flux was found (Pair Recombination Case). For the activation energy of enhanced self-diffusion, a value Q/sub DS//sup irr/ = 0.50 eV and for the migration activation energy of self-interstitials a value of E/sub I//sup M/ = 1.00 eV was determined. From a quantitative evaluation of the measured data the existence of a defect conversion mechanism at high temperatures is derived and arguments for the existence of stable crowdions at low temperatures are given

  16. Pyrolysis of nickel zirconyl oxalate

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, V.B.; Mehrotra, P.N.

    1982-06-30

    Nickel zirconyl oxalate hexahydrate (NiZrOx) is delta prepared and characterised by I.R. spectral and chemical analysis. Its thermal decomposition has been investigated by employing TG, DTG, DTA and chemical analysis. End product was identified by X-ray diffraction studies. The decomposition proceeds through four steps i) dehydration of NiZrOx in two steps, ii) partial decomposition of oxalate to give an oxalate carbonate intermediate, iii) decomposition of oxalate to give a non-stoichiometric carbonate and iv) decomposition of this non-stoichiometric carbonate to give the end product a mixture of NiO + ZrO/sub 2/. On the basis of the results obtained, a tentative scheme for the decomposition of NiZrOx is proposed.

  17. Microstructural evolution in nickel alloy C-276 after Ar-ion irradiation at elevated temperature

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Shuoxue [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072 (China); He, Xinfu [China Institute of Atomic Energy, Beijing 102413 (China); Li, Tiecheng [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Ma, Shuli; Tang, Rui [Nuclear Power Institute of China, Chengdu 610041 (China); Guo, Liping, E-mail: guolp@whu.edu.cn [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072 (China)

    2012-10-15

    In present work, the irradiation damage in nickel-base alloy C-276 irradiated with Ar-ions was studied. Specimens of C-276 alloy were subjected to an irradiation of Ar-ions (with 120 keV) to dose levels of 6 and 10 dpa at 300 and 550 Degree-Sign C, respectively. The size distributions and densities of dislocation loops caused by irradiation were investigated with transmission electron microscopy. Irradiation hardening due to the formation of the loops was calculated using the dispersed barrier-hardening model, showing that irradiation hardening was greatest at 300 Degree-Sign C/6 dpa. The microstructure evolution induced by Ar-ion irradiation (0-10 dpa) in nickel-base alloy C-276 has been studied using a multi-scale modeling code Radieff constructed based on rate theory, and the size of dislocation loops simulated by Radieff was in good agreement with the experiment. - Highlights: Black-Right-Pointing-Pointer High density of dislocation loops appeared after Ar ions irradiation. Black-Right-Pointing-Pointer Irradiation hardening due to the formation of loops was calculated by the DBH model. Black-Right-Pointing-Pointer Size of loops simulated by Radieff was in good agreement with the experiment.

  18. A Computational Study of Nickel Ferrite

    International Nuclear Information System (INIS)

    Magnetic properties and electronic structure of nickel ferrite are studied using hybrid density functional theory. In the calculation, the exchange correlation is a mixture of Fock exchange, local spin density approximation (LSDA) and generalized gradient approximation (GGA). The weighting factor (w) of the Fock term and a scaling factor of the 3d orbitals of Fe3+ (α) are introduced as fitting parameters. All nearest neighbor exchange constants for inter and intra A and B sites of the spinel structure of nickel ferrite are calculated from the energies of different magnetic structures. Local magnetic moments of the ions on the A and B sites are calculated by the Muelliken population analysis. Moreover, the density of states is calculated to show the insulating nature of nickel ferrite. The band gap and intra-site Coulomb repulsion are extracted from the calculated density of states. The charge density map is calculated to visualize the electrons in nickel ferrite

  19. NICKEL SPECIATION OF RESIDUAL OIL ASH

    Science.gov (United States)

    EPA GRANT NUMBER: R827649C002Title: Nickel Speciation Of Residual Oil AshInvestigators: Kevin C. Galbreath, John Won, Frank E. Huggins, Gerald P. Huffman, Christopher J. Zygarlicke, Donald L. TomanInstitution: University of North Dakota<...

  20. The NTS-2 nickel-hydrogen battery

    Science.gov (United States)

    Betz, F.

    1977-01-01

    Features of the first operational nickel hydrogen battery are described as well as experiences encountered during its testing and installation. Battery performance since launching of the NTS-2 satellite is discussed.

  1. Preparation of nickel nanoparticles in emulsion

    Institute of Scientific and Technical Information of China (English)

    ZHANG You-xian; FU Wen-jie; AN Xue-qin

    2008-01-01

    The nickel nanoparticles with different sizes and spherical shape were prepared by the reduction of nickel sulfate with sodium borohydride in the water-in-oil emulsions of water/SDBS(sodium dodecylbenzene sulfonate)/n-pentanol/n-heptane. The effects of aging time, molar ratio of water to SDBS(R) and the concentration of nickel sulfate on the size of particles were studied. The samples were characterized by transmission electron microscopy(TEM) and inductively coupled plasma spectrometry(ICP). The results show that the average particle size changes from 20 to 40 nm by adjusting aging time (15-30 min) and R (9-11.5). The concentration of nickel sulfate of 1.0 mol/L is the favorite condition.

  2. Determination of electroless deposition by chemical nickeling

    OpenAIRE

    Badida, M.; M. Gombár; L. Sobotová; J. Kmec

    2013-01-01

    Increasing of technical level and reliability of machine products in compliance with the economical and ecological terms belongs to the main trends of the industrial development. During the utilisation of these products there arise their each other contacts and the interaction with the environment. That is the reason for their surface degradation by wear effect, corrosion and other influences. The chemical nickel-plating allows autocatalytic deposition of nickel from water solutions in the fo...

  3. Effect of Some Process Variables on Nickel Electroplating of Low Carbon Steel

    Directory of Open Access Journals (Sweden)

    Oluleke OLUWOLE

    2011-06-01

    Full Text Available This research work investigated the effect of current density, bath concentration, bath solution volume and electroplating time on nickel electroplating of low carbon steel. Varying voltage between 0.3 and 0.8 V, bath concentration between 0.27 g/cm3 (0.79 mol/dm3 and 0.35 g/cm3 (1.02 mol/dm3, electroplating time between 10 and 30 minutes and bath solution volume between 200 and 700 cm3, the effect of these process variables on electroplating was studied. The temperature was kept in conformity with Watt’s method at 50 ±5°C. It was observed that a bath concentration of 0.31 g/cm3 (0.89 Mol/dm3 concentration gave the best nickel deposit at 0.5V for 15 minutes. This would correspond to a Watt solution of composition: nickel sulphate-230 g/l, nickel chloride-46.5 g/l and boric acid-30.8 g/l with a pH of 4.18. Higher Watt bath concentration did not yield good results as plating thickness decreased and there was no luster. It was also observed that increasing time of plating served to increase plating thickness and did not affect brightness of plating. However non-uniform nickel deposition was observed for longer plating time. Increase in voltage served to increase rate of electrodeposition with the exceptions of 0.7 V where a long streak of plating was observed on substrate instead of uniform plating and 0.8V where plating lacked brightness having a burnt appearance. Bath volumes of between 200-500 cm3 were observed to be best for the coupons used (15mm × 20mm. Bath volumes above 500 cm^3 gave black plating appearance.

  4. Chemoorganotrophic Bioleaching of Olivine for Nickel Recovery

    Directory of Open Access Journals (Sweden)

    Yi Wai Chiang

    2014-06-01

    Full Text Available Bioleaching of olivine, a natural nickel-containing magnesium-iron-silicate, was conducted by applying chemoorganotrophic bacteria and fungi. The tested fungus, Aspergillus niger, leached substantially more nickel from olivine than the tested bacterium, Paenibacillus mucilaginosus. Aspergillus niger also outperformed two other fungal species: Humicola grisae and Penicillium chrysogenum. Contrary to traditional acid leaching, the microorganisms leached nickel preferentially over magnesium and iron. An average selectivity factor of 2.2 was achieved for nickel compared to iron. The impact of ultrasonic conditioning on bioleaching was also tested, and it was found to substantially increase nickel extraction by A. niger. This is credited to an enhancement in the fungal growth rate, to the promotion of particle degradation, and to the detachment of the stagnant biofilm around the particles. Furthermore, ultrasonic conditioning enhanced the selectivity of A. niger for nickel over iron to a value of 3.5. Pre-carbonating the olivine mineral, to enhance mineral liberation and change metal speciation, was also attempted, but did not result in improvement as a consequence of the mild pH of chemoorganotrophic bioleaching.

  5. Performance improvement of pasted nickel electrodes with multi-wall carbon nanotubes for rechargeable nickel batteries

    International Nuclear Information System (INIS)

    Carbon nanotubes (CNTs) were employed as a functional additive to improve the electrochemical performance of pasted nickel-foam electrodes for rechargeable nickel-based batteries. The nickel electrodes were prepared with spherical β-Ni(OH)2 powder as the active material and various amounts of CNTs as additives. Galvanostatic charge/discharge cycling tests showed that in comparison with the electrode without CNTs, the pasted nickel electrode with added CNTs exhibited better electrochemical properties in the chargeability, specific discharge capacity, active material utilization, discharge voltage, high-rate capability and cycling stability. Meanwhile, the CNT addition also lowered the packing density of Ni(OH)2 particles in the three-dimensional porous nickel-foam substrate, which could lead to the decrease in the active material loading and discharge capacity of the electrode. Hence, the amount of CNTs added to Ni(OH)2 should be optimized to obtain a high-performance nickel electrode, and an optimum amount of CNT addition was found to be 3 wt.%. The superior electrochemical performance of the nickel electrode with CNTs could be attributed to lower electrochemical impedance and less γ-NiOOH formed during charge/discharge cycling, as indicated by electrochemical impedance spectroscopy and X-ray diffraction analyses. Thus, it was an effective method to improve the electrochemical properties of pasted nickel electrodes by adding an appropriate amount of CNTs to spherical Ni(OH)2 as the active material

  6. Amino olefin nickel(I) and nickel(0) complexes as dehydrogenation catalysts for amine boranes

    NARCIS (Netherlands)

    M. Vogt; B. de Bruin; H. Berke; M. Trincado; H. Grützmacher

    2011-01-01

    A rare paramagnetic organometallic nickel(I) olefin complex can be isolated using the ligand bis(5H-dibenzo[a,d]cyclohepten-5-yl)amine. This complex and related nickel(0) hydride complexes show very high catalytic activity in the dehydrogenation of dimethylamino borane with release of one equivalent

  7. AN ELECTROPLATING METHOD OF FORMING PLATINGS OF NICKEL, COBALT, NICKEL ALLOYS OR COBALT ALLOYS

    DEFF Research Database (Denmark)

    1997-01-01

    An electroplating method of forming platings of nickel, cobalt, nickel alloys or cobalt alloys with reduced stresses in an electrodepositing bath of the type: Watt's bath, chloride bath or a combination thereof, by employing pulse plating with periodic reverse pulse and a sulfonated naphthalene...

  8. Corrosion properties of plasma deposited nickel and nickel-based alloys

    Czech Academy of Sciences Publication Activity Database

    Voleník, Karel; Pražák, M.; Kalabisová, E.; Kreislová, K.; Had, J.; Neufuss, Karel

    2003-01-01

    Roč. 48, č. 3 (2003), s. 215-226. ISSN 0001-7043 R&D Projects: GA ČR GA106/99/0298 Institutional research plan: CEZ:AV0Z2043910 Keywords : plasma deposits, nickel , nickel -based alloys Subject RIV: JK - Corrosion ; Surface Treatment of Materials

  9. Preparation of fine nickel powders via reduction of nickel hydrazine complex precursors

    Institute of Scientific and Technical Information of China (English)

    HUANG Guo-yong; XU Sheng-ming; XU Gang; LI Lin-yan; ZHANG Li-feng

    2009-01-01

    Fine nickel(Ni) powders with controllable particle sizes were synthesized via the reduction of nickel hydrazine complex precursors of pure [Ni(N2H4)2]Cl2 and a mixture of [Ni(N2H4)2]Cl2 and [Ni(N2H4)3]Cl2 in aqueous solution. The mechanism of the formation of metallic Ni powders experiences the reduction of nickel hydroxide by hydrazine released from the ligand exchange reaction between nickel hydrazine complex and NaOH. In comparison with the method of preparing Ni powders from nickel salts, the method of making Ni powders via the reduction of nickel hydrazine complex precursors shows the advantages of using half dosage of hydrazine for complete reduction of nickel ions in solution, and the obtained Ni particles show less agglomeration and better dispersibility. Moreover, the average particle size of nickel powders can be controlled from 180 to 260 nm by adjusting the reaction molar ratio and concentration.

  10. A review of nickel hydrogen battery technology

    Science.gov (United States)

    Smithrick, John J.; Odonnell, Patricia M.

    1995-01-01

    This paper on nickel hydrogen batteries is an overview of the various nickel hydrogen battery design options, technical accomplishments, validation test results and trends. There is more than one nickel hydrogen battery design, each having its advantage for specific applications. The major battery designs are individual pressure vessel (IPV), common pressure vessel (CPV), bipolar and low pressure metal hydride. State-of-the-art (SOA) nickel hydrogen batteries are replacing nickel cadmium batteries in almost all geosynchronous orbit (GEO) applications requiring power above 1 kW. However, for the more severe low earth orbit (LEO) applications (greater than 30,000 cycles), the current cycle life of 4000 to 10,000 cycles at 60 percent DOD should be improved. A NASA Lewis Research Center innovative advanced design IPV nickel hydrogen cell led to a breakthrough in cycle life enabling LEO applications at deep depths of discharge (DOD). A trend for some future satellites is to increase the power level to greater than 6 kW. Another trend is to decrease the power to less than 1 kW for small low cost satellites. Hence, the challenge is to reduce battery mass, volume and cost. A key is to develop a light weight nickel electrode and alternate battery designs. A common pressure vessel (CPV) nickel hydrogen battery is emerging as a viable alternative to the IPV design. It has the advantage of reduced mass, volume and manufacturing costs. A 10 Ah CPV battery has successfully provided power on the relatively short lived Clementine Spacecraft. A bipolar nickel hydrogen battery design has been demonstrated (15,000 LEO cycles, 40 percent DOD). The advantage is also a significant reduction in volume, a modest reduction in mass, and like most bipolar designs, features a high pulse power capability. A low pressure aerospace nickel metal hydride battery cell has been developed and is on the market. It is a prismatic design which has the advantage of a significant reduction in volume and a

  11. Nickel acts as an adjuvant during cobalt sensitization

    DEFF Research Database (Denmark)

    Bonefeld, Charlotte Menne; Nielsen, Morten Milek; Vennegaard, Marie T.;

    2015-01-01

    Metal allergy is the most frequent form of contact allergy with nickel and cobalt being the main culprits. Typically, exposure comes from metal-alloys where nickel and cobalt co-exist. Importantly, very little is known about how co-exposure to nickel and cobalt affects the immune system. We...... in the draining lymph nodes compared to mice sensitized with cobalt alone. In contrast, the presence of cobalt during nickel sensitization only induced an increased CD8(+) T cell proliferation during challenge to nickel. Thus, the presence of nickel during cobalt sensitization potentiated the challenge response...

  12. Cold-impregnated aluminium. A new source of nickel exposure.

    Science.gov (United States)

    Lidén, C

    1994-07-01

    A new technique for finishing anodized aluminium was introduced during the 1980s--cold impregnation with nickel. Nickel is available on the surface of cold-impregnated aluminium, as shown by the dimethylglyoxime test. Chemical analysis with EDXA showed that nickel was in the form of NiSO4. A case of work-related allergic contact dermatitis in an engraver with nickel allergy is reported. It transpired that the patient was exposed to nickel in connection with aluminium. It is concluded that cold-impregnated aluminium is a new source of nickel exposure, probably previously unknown to dermatologists. PMID:7924288

  13. The Black Studies Boondoggle

    Science.gov (United States)

    Long, Richard A.

    1970-01-01

    Indicates tendencies dangerous to the basic purpose of Black Studies, and identifies four external challeges--imperialism, paternalism, nihilism, and materialism. An internal challenge is considered to be the use of European and Establishment constructs to analyze black reality. (DM)

  14. Dynamics of black holes

    OpenAIRE

    Hayward, Sean A.

    2008-01-01

    This is a review of current theory of black-hole dynamics, concentrating on the framework in terms of trapping horizons. Summaries are given of the history, the classical theory of black holes, the defining ideas of dynamical black holes, the basic laws, conservation laws for energy and angular momentum, other physical quantities and the limit of local equilibrium. Some new material concerns how processes such as black-hole evaporation and coalescence might be described by a single trapping h...

  15. Noncommutative black holes

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-DomInguez, J C [Instituto de Fisica de la Universidad de Guanajuato PO Box E-143, 37150 Leoen Gto. (Mexico); Obregon, O [Instituto de Fisica de la Universidad de Guanajuato PO Box E-143, 37150 Leoen Gto. (Mexico); RamIrez, C [Facultad de Ciencias FIsico Matematicas, Universidad Autonoma de Puebla, PO Box 1364, 72000 Puebla (Mexico); Sabido, M [Instituto de Fisica de la Universidad de Guanajuato PO Box E-143, 37150 Leoen Gto. (Mexico)

    2007-11-15

    We study noncommutative black holes, by using a diffeomorphism between the Schwarzschild black hole and the Kantowski-Sachs cosmological model, which is generalized to noncommutative minisuperspace. Through the use of the Feynman-Hibbs procedure we are able to study the thermodynamics of the black hole, in particular, we calculate Hawking's temperature and entropy for the 'noncommutative' Schwarzschild black hole.

  16. Black Hole Statistics

    OpenAIRE

    Strominger, Andrew

    1993-01-01

    The quantum statistics of charged, extremal black holes is investigated beginning with the hypothesis that the quantum state is a functional on the space of closed three-geometries, with each black hole connected to an oppositely charged black hole through a spatial wormhole. From this starting point a simple argument is given that a collection of extremal black holes obeys neither Bose nor Fermi statistics. Rather they obey an exotic variety of particle statistics known as ``infinite statist...

  17. Phantom Black Holes

    OpenAIRE

    Gao, C. J.; Zhang, S. N.

    2006-01-01

    The exact solutions of electrically charged phantom black holes with the cosmological constant are constructed. They are labelled by the mass, the electrical charge, the cosmological constant and the coupling constant between the phantom and the Maxwell field. It is found that the phantom has important consequences on the properties of black holes. In particular, the extremal charged phantom black holes can never be achieved and so the third law of thermodynamics for black holes still holds. ...

  18. Hydrothermal processing of nickel containing biomining or bioremediation biomass

    Energy Technology Data Exchange (ETDEWEB)

    Clercq, M. le; Adschiri, Tadafumi; Arai, Kunio [Tohoku Univ., Sendai (Japan). Dept. of Chemical Engineering

    2001-07-01

    The feasibility of recovering nickel and producing biofuels from nickel containing biomining or bioremediation biomass by a hydrothermal process has been investigated. Experiments were concerned with the reactions of nickel and biomass containing solutions (model solutions and an extract of Berkheya coddii) in hot compressed water between 200 and 375{sup o}C at 25 MPa. We found that in this temperature range nickel is soluble in aqueous solutions containing histidine, an amino acid present in high concentrations in nickel accumulators. The thermal decomposition products of the biomass reduce the histidine complexed nickel ions to metallic nickel. This reduction proceeds on metallic surfaces, and the nickel is deposited on the surface of the metal as a nickel or nickel/char layer. No added reducing agent such as hydrogen is required. An extract of the nickel bioaccumulator B. coddii and total biomass of B. coddii behaved similarly to our model solutions. Based on our results we propose a three-step hydrothermal process for the recovery of nickel and biofuel form nickel containing biomass. (Author)

  19. Black Nuns as Educators.

    Science.gov (United States)

    Rector, Theresa A.

    1982-01-01

    Traces the contributions of Black Roman Catholic nuns to Black education in the United States since the early 1800s. Also shows that, despite declining membership, the three existing religious orders continue to be active in Black education and social change. (GC)

  20. Black Holes in Higher Dimensions (Black Strings and Black Rings)

    CERN Document Server

    Kleihaus, Burkhard

    2016-01-01

    The last three years have again seen new exciting developments in the area of higher dimensional black objects. For black objects with noncompact higher dimensions, the solution space was exlored further within the blackfold approach and with numerical schemes, yielding a large variety of new families of solutions, while limiting procedures created so-called super-entropic black holes. Concerning compact extra dimensions, the sequences of static nonuniform black strings in five and six dimensions were extended to impressively large values of the nonuniformity parameter with extreme numerical precision, showing that an oscillating pattern arises for the mass, the area or the temperature, while approaching the conjectured double-cone merger solution. Besides the presentation of interesting new types of higherdimensional solutions, also their physical properties were addressed in this session. While the main focus was on Einstein gravity, a significant number of talks also covered Lovelock theories.

  1. The biocompatibility of dense and porous Nickel-Titanium produced by selective laser melting

    Energy Technology Data Exchange (ETDEWEB)

    Habijan, T., E-mail: Tim.Habijan@rub.de [Surgical Research, Department of Surgery, BG Kliniken Bergmannsheil, Ruhr-University Bochum, Buerkle-de-la-Camp-Platz 1, 44789 Bochum (Germany); Haberland, C.; Meier, H. [Institute Product and Service Engineering, Ruhr-University Bochum (Germany); Frenzel, J. [Institute for Materials, Ruhr-University Bochum (Germany); Wittsiepe, J. [Department of Hygiene, Social and Environmental Medicine, Ruhr-University Bochum (Germany); Wuwer, C.; Greulich, C.; Schildhauer, T.A.; Koeller, M. [Surgical Research, Department of Surgery, BG Kliniken Bergmannsheil, Ruhr-University Bochum, Buerkle-de-la-Camp-Platz 1, 44789 Bochum (Germany)

    2013-01-01

    Nickel-Titanium shape memory alloys (NiTi-SMA) are of biomedical interest due to their unusual range of pure elastic deformability and their elastic modulus, which is closer to that of bone than any other metallic or ceramic material. Newly developed porous NiTi, produced by Selective Laser Melting (SLM), is currently under investigation as a potential carrier material for human mesenchymal stem cells (hMSC). SLM enables the production of highly complex and tailor-made implants for patients on the basis of CT data. Such implants could be used for the reconstruction of the skull, face, or pelvis. hMSC are a promising cell type for regenerative medicine and tissue engineering due to their ability to support the regeneration of critical size bone defects. Loading porous SLM-NiTi implants with autologous hMSC may enhance bone growth and healing for critical bone defects. The purpose of this study was to assess whether porous SLM-NiTi is a suitable carrier for hMSC. Specimens of varying porosity and surface structure were fabricated via SLM. hMSC were cultured for 8 days on NiTi specimens, and cell viability was analyzed using two-color fluorescence staining. Viable cells were detected on all specimens after 8 days of cell culture. Cell morphology and surface topography were analyzed by scanning electron microscopy (SEM). Cell morphology and surface topology were dependent on the orientation of the specimens during SLM production. The Nickel ion release can be reduced significantly by aligned laser processing conditions. The presented results clearly attest that both dense SLM-NiTi and porous SLM-NiTi are suitable carriers for hMSC. Nevertheless, before carrying out in vivo studies, some work on optimization of the manufacturing process and post-processing is required. - Highlights: Black-Right-Pointing-Pointer Specimens, varying in porosity and surface structure were produced via SLM. Black-Right-Pointing-Pointer Biocompatibility of these specimens was analyzed. Black

  2. Nickel-base alloys combat corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Agarwal, D.C. [VDM Technologies Corp., Houston, TX (United States); Herda, W. [Krupp-VDM GmbH, Werdohl (Germany)

    1995-06-01

    The modern chemical process industry must increase production efficiency to remain competitive. Manufacturers typically meet this challenge by utilizing higher temperatures and pressures, and more-corrosive catalysts. At the same time, the industry has to solve the technical and commercial problems resulting from rigid environmental regulations. To overcome these obstacles, new alloys having higher levels of corrosion resistance have been developed. These materials are based on increased understanding of the physical metallurgy of nickel-base alloys, especially the role of alloying elements. Results of many studies have led to innovations in nickel-chromium-molybdenum alloys containing both high and low amounts of nickel. Higher molybdenum and chromium contents, together with nitrogen additions, have opened up an entirely new class of alloys having unique properties. In addition, a new chromium-base, fully wrought super stainless steel shows excellent promise in solving many corrosion problems. These newer alloys have the ability to combat uniform corrosion, localized corrosion, and stress-corrosion cracking in the harsh halogenic environment of the chemical process industry. This article briefly lists some of the major highlights and corrosion data on recent nickel-chromium-molybdenum and nickel-molybdenum alloys, and the development of a chromium-base, wrought super-austenitic alloy known as Nicrofer 3033 (Alloy 33). Some comparisons with existing alloys are presented, along with a few commercial applications.

  3. Experimental study on the formation and growth of electroless nickel-boron coatings from borohydride-reduced bath on mild steel

    Energy Technology Data Exchange (ETDEWEB)

    Vitry, Veronique, E-mail: veronique.vitry@umons.ac.be [Service de Metallurgie, Universite de Mons, Rue de l' Epargne 56, 7000 Mons (Belgium); Sens, Adeline [Service de Metallurgie, Universite de Mons, Rue de l' Epargne 56, 7000 Mons (Belgium); Kanta, Abdoul-Fatah [Service de Sciences des Materiaux, Universite de Mons, Rue de l' Epargne 56, 7000 Mons (Belgium); Delaunois, Fabienne [Service de Metallurgie, Universite de Mons, Rue de l' Epargne 56, 7000 Mons (Belgium)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer Initiation mechanism of electroless Ni-B on St-37 steel has been identified. Black-Right-Pointing-Pointer Different phases of the plating process were observed and identified. Black-Right-Pointing-Pointer Influence of chemical heterogeneity on coating morphology was revealed. Black-Right-Pointing-Pointer Batch replenishment of the plating bath induces new germination phase. - Abstract: Quality and homogeneity of electroless nickel-boron coatings are very important for applications in corrosion and electronics and are completely dependent on the formation of the deposit. The growth and formation process of electroless nickel-boron was investigated by immersing mild steel (St-37) samples in an un-replenished bath for various periods of time (from 5 s to 1 h). The coatings obtained at the different stages of the process were then characterized: thickness was measured by SEM, morphology was observed, weight gain was recorded and top composition of the coatings was obtained from XPS. Three main phases were identified during the coating formation and links between plating time, instantaneous deposition rate, chemistry of last formed deposit and morphology were established. The mechanism for initial deposition on steel substrate for borohydride-reduced electroless nickel bath was also observed. Those results were confronted with chemistry evolution in the unreplenished plating bath during the process. This allowed getting insight about phenomena occurring in the plating bath and their influence on coating formation.

  4. Preliminary evaluation of electrowinning for nickel scrap processing

    International Nuclear Information System (INIS)

    Purification of the 70,000 to 245,000 tons of diffusion plant nickel scrap permit its use in a variety of DOE and, with establishment of de minimus standards, foreign and domestic industrial applications. Nickel recycle would also substantially decrease DOE legacy wastes. This report presents data on electrolytes and separations which could be used in electrolytic purification of radiologically contaminated nickel scrap from first generation diffusion plants. Potentiometric scans and plating tests indicate that both industrial electrolytes, buffered nickel sulfate-sodium chloride and nickel chloride, provide good current densities. Electrolytes which contain ammonium thiocyanate or ammonium chloride also perform well. Nickel does not plate appreciably from nitrate solutions because the nitrate was preferentially reduced to nitrite. Solvent extractions of cobalt, a common contaminant in commercial nickel, and pertechnate, a radiological contaminant expected in DOE nickel scrap, are also successful

  5. Environmentally Assisted Cracking of Nickel Alloys - A Review

    Energy Technology Data Exchange (ETDEWEB)

    Rebak, R

    2004-07-12

    Nickel can dissolve a large amount of alloying elements while still maintaining its austenitic structure. That is, nickel based alloys can be tailored for specific applications. The family of nickel alloys is large, from high temperature alloys (HTA) to corrosion resistant alloys (CRA). In general, CRA are less susceptible to environmentally assisted cracking (EAC) than stainless steels. The environments where nickel alloys suffer EAC are limited and generally avoidable by design. These environments include wet hydrofluoric acid and hot concentrated alkalis. Not all nickel alloys are equally susceptible to cracking in these environments. For example, commercially pure nickel is less susceptible to EAC in hot concentrated alkalis than nickel alloyed with chromium (Cr) and molybdenum (Mo). The susceptibility of nickel alloys to EAC is discussed by family of alloys.

  6. Rapid nickel oxalate thermal decomposition for producing fine porous nickel metal powders

    International Nuclear Information System (INIS)

    Precursor nickel oxalate powder was entrained in pure argon and a 5% hydrogen-in-argon carrier gas flow and carried through a heated transport tube reactor. The reactor wall temperature was maintained at 748-1018 K for residence times less than 4 s. Rapid reaction was possible because of high particle heating rates. A 5% addition of hydrogen to the carrier allowed for the synthesis of a high-purity elemental nickel powder with low residual oxygen content. Product particles consisted of nano-sized primary particles contained within an overall microcontainer matrix. Primary nickel particles nucleated within the precursor microcontainer matrix, followed by a coalescence period. The product powder was characterized as 2-40 μm diameter microcontainer particles comprised of nano-sized nickel primary particles with diameters of 20-70 nm. The production of porous elemental nickel powder via the aerosol flow thermal decomposition of nickel oxalate results in powder with acceptable electrical properties and is more benign and potentially cheaper than the current commercial process for nickel powder production

  7. Rapid nickel oxalate thermal decomposition for producing fine porous nickel metal powders

    Energy Technology Data Exchange (ETDEWEB)

    Carney, C.S. [University of Colorado, Department of Chemical and Biological Engineering, UCB 424, Boulder, CO 80309-0424 (United States); Gump, C.J. [University of Colorado, Department of Chemical and Biological Engineering, UCB 424, Boulder, CO 80309-0424 (United States); Weimer, A.W. [University of Colorado, Department of Chemical and Biological Engineering, UCB 424, Boulder, CO 80309-0424 (United States)]. E-mail: alan.weimer@colorado.edu

    2006-09-15

    Precursor nickel oxalate powder was entrained in pure argon and a 5% hydrogen-in-argon carrier gas flow and carried through a heated transport tube reactor. The reactor wall temperature was maintained at 748-1018 K for residence times less than 4 s. Rapid reaction was possible because of high particle heating rates. A 5% addition of hydrogen to the carrier allowed for the synthesis of a high-purity elemental nickel powder with low residual oxygen content. Product particles consisted of nano-sized primary particles contained within an overall microcontainer matrix. Primary nickel particles nucleated within the precursor microcontainer matrix, followed by a coalescence period. The product powder was characterized as 2-40 {mu}m diameter microcontainer particles comprised of nano-sized nickel primary particles with diameters of 20-70 nm. The production of porous elemental nickel powder via the aerosol flow thermal decomposition of nickel oxalate results in powder with acceptable electrical properties and is more benign and potentially cheaper than the current commercial process for nickel powder production.

  8. Nickel adsorption by wild type and nickel resistant isolate of chlorella sp

    International Nuclear Information System (INIS)

    Use of unicellular green microalgae has several advantages over conventional methods for removing heavy metals from contaminated sites. Here, a comparative study was made to investigate nickel detoxification mechanisms between a wild type(WT) Chlorella sp. and a nickel resistant, EMS-5 cell line isolated from the same species by EMS (Ethyl Methane Sulphonate) mutagenesis. Results showed that the growth rate of the tested algal cells was inhibited with increasing nickel concentrations in the liquid growth medium. Higher ID/sub 50/ value of EMS-5 compared to the WT revealed some degree of resistance to nickel. Removal and adsorption of Ni/sub 2+/ were found rapid during the first few hours in both the algal cultures when exposed to 50 microM Ni/sub 2+/. However, kinetic experiments showed significantly higher removal and adsorption of Ni by EMS-5 compared to the WT throughout the treatment hours. Besides, the total nickel accumulation, surface bound and intracellular nickel in EMS-5 was significantly higher to that of the WT. Hence the EMS-5 appeared more resistant to nickel. (author)

  9. Nonstationary analogue black holes

    International Nuclear Information System (INIS)

    We study the existence of analogue nonstationary spherically symmetric black holes. The prime example is the acoustic model see Unruh (1981 Phys. Rev. Lett. 46 1351). We consider also a more general class of metrics that could be useful in other physical models of analogue black and white holes. We give examples of the appearance of black holes and of disappearance of white holes. We also discuss the relation between the apparent and the event horizons for the case of analogue black holes. In the end we study the inverse problem of determination of black or white holes by boundary measurements for the spherically symmetric nonstationary metrics. (paper)

  10. Black Hole Battery

    Science.gov (United States)

    Levin, Janna; D'Orazio, Daniel

    2016-03-01

    Black holes are dark dead stars. Neutron stars are giant magnets. As the neutron star orbits the black hole, an electronic circuit forms that generates a blast of power just before the black hole absorbs the neutron star whole. The black hole battery conceivably would be observable at cosmological distances. Possible channels for luminosity include synchro-curvature radiation, a blazing fireball, or even an unstable, short-lived black hole pulsar. As suggested by Mingarelli, Levin, and Lazio, some fraction of the battery power could also be reprocessed into coherent radio emission to populate a subclass of fast radio bursts.

  11. Hydroponic screening of black locust families for heavy metal tolerance and accumulation.

    Science.gov (United States)

    Župunski, Milan; Borišev, Milan; Orlović, Saša; Arsenov, Danijela; Nikolić, Nataša; Pilipović, Andrej; Pajević, Slobodanka

    2016-06-01

    Present work examines phytoextraction potential of four black locust families (half-sibs 54, 56, 115, and 135) grown hydroponically. Plants were treated with 6 ppm of cadmium (Cd), 100 ppm of nickel (Ni), and 40 ppm of lead (Pb) added in Hoagland nutrient solution, accompanying with simultaneously applied all three metals. Responses to metals exposure among families were different, ranging from severe to slight reduction of root and shoot biomass production of treated plants. Calculated tolerance indices are indicating tested families as highly tolerant (Ti > 60). Family 135 had the lowest tolerance index, pointing that it was highly susceptible to applied metals. Comparing photosynthetic activities of tested families it has been noticed that they were highly sensitive to stress induced by heavy metals. Net photosynthetic rate of nickel treated plants was the most affected by applied concentration. Cadmium and nickel concentrations in stems and leaves of black locust families exceeded 100 mg Cd kg(-1) and 1000 mg Ni kg(-1), in both single and multipollution context. On the contrary, accumulation of lead in above ground biomass was highly affected by multipollution treatment. Tf and BCF significantly varied between investigated treatments and families of black locust. Concerning obtained results of heavy metals accumulation and tolerance of black locust families can be concluded that tested families might be a promising tool for phytoextraction purposes, but it takes to be further confirmed in field trials. PMID:26332106

  12. Mechanical strength of carbon nanotube nickel nanocomposites

    Science.gov (United States)

    Sun, Ying; Sun, Jianren; Liu, Miao; Chen, Quanfang

    2007-12-01

    Carbon nanotubes (CNTs), including single-walled CNT (SWCNT) and multi-walled CNT (MWCNT), have been regarded as the stiffest and strongest materials ever developed and are promising reinforcement fillers for developing nanocomposites. However, the scientific community has been puzzled about the reinforcement efficiency. Here we report CNT-reinforced nickel nanocomposites fabricated with an innovative electrochemical co-deposition process for achieving good interfacial bonding between CNT and metallic matrices. Test results show that Ni/SWCNT composite produces a tensile strength as high as 2 GPa, which is more than three times stronger than that of pure nickel. The mechanical strength of Ni/CNT nanocomposites is dependent on CNT addition, while the fracture strain remains similar or better than that of pure nickel. The good reinforcement of CNT/metal nanocomposites is attributed to the good interfacial bonding as well as the stiffer matrix nature.

  13. Direct electroless nickel plating on silicon surface

    Institute of Scientific and Technical Information of China (English)

    HU Guanghui; WU Huihuang; YANG Fangzu

    2004-01-01

    Direct electroless nickel plating on n-Si(100)wafers in alkaline solutions was demonstrated without any activation procedure in advance, the effect of pH and temperature of the solutions on size of metal particles in deposits was examined, and also the element contents of deposits were analyzed by energy disperse spectroscopy (EDS). The results indicated that the size of metal particles increases with increasing temperature or decreasing pH. The possible mechanism of nickel deposition on n-Si(100) was discussed in terms of semiconductor electrochemistry, and the formation of nickel seed crystal on Si was mainly attributed to the generation of atomic hydrogen by electron capture of water molecule from the semiconductor in alkaline solutions.

  14. Black Flowers in Flatland

    CERN Document Server

    Alkac, Gokhan; Tekin, Bayram

    2016-01-01

    Asymptotically flat black holes in $2+1$ dimensions are a rarity. We study the recently found black flower solutions (asymptotically flat black holes with deformed horizons), static black holes, rotating black holes and the dynamical black flowers (black holes with radiative gravitons ) of the purely quadratic version of new massive gravity. We show how they appear in this theory and we also show that they are also solutions to the infinite order extended version of the new massive gravity, that is the Born-Infeld extension of new massive gravity with an amputated Einsteinian piece. The same metrics also solve the topologically extended versions of these theories, with modified conserved charges and the thermodynamical quantities, such as the Wald entropy. Besides these we find new conformally flat radiating type solutions to these extended gravity models. We also show that these metrics do not arise in Einstein's gravity coupled to physical perfect fluids.

  15. Nickel release from inexpensive jewelry and hair clasps purchased in an EU country - Are consumers sufficiently protected from nickel exposure?

    DEFF Research Database (Denmark)

    Thyssen, Jacob Pontoppidan; Menné, Torkil; Johansen, Jeanne Duus

    2009-01-01

    population was protected from high cutaneous nickel concentrations. Despite a decrease, the prevalence of nickel allergy remains high as nearly 10% of young women are nickel allergic. OBJECTIVE: This study aimed to perform dimethylglyoxime (DMG) testing of inexpensive jewelry and hair clasps purchased from...... random stores in Copenhagen, Denmark to detect the proportion of items that may result in nickel allergy. METHODS: Inexpensive jewelry and hair clasps were purchased from 36 stores and street vendors in Copenhagen and were later tested for nickel release using the DMG test. RESULTS: The study showed......BACKGROUND: Nickel allergic subjects are at risk factor of acquiring hand eczema. In 1990 and 1994, respectively, Denmark and member states in the EU regulated nickel release from selected consumer products. The intention was that the nickel epidemic could be controlled and prevented if the general...

  16. Highly active gauze-supported skeletal nickel catalysts

    OpenAIRE

    Fow, Kam Loon; Ganapathi, Murugan; Stassen, Ivo; Fransaer, Jan; Binnemans, Koen; De Vos, Dirk E.

    2013-01-01

    Gauze-supported skeletal nickel catalysts were prepared by electrodeposition of Ni–Zn alloys from an acetamide–DMSO2–NiCl2–ZnCl2 quaternary melt, followed by chemical or electrochemical leaching of zinc from the alloys. The activity and selectivity of the structured RANEY® nickel surpass those of commercial RANEY® nickel in the hydrogenation of acetophenone.

  17. 40 CFR 721.5325 - Nickel acrylate complex.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Nickel acrylate complex. 721.5325... Substances § 721.5325 Nickel acrylate complex. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance nickel acrylate complex (PMN P-85-1034) is subject to reporting...

  18. Initial stages of indoor atmospheric corrosion of electronics contact metals in humid tropical climate: tin and nickel

    International Nuclear Information System (INIS)

    Samples of electrolytic tin and nickel have been exposed for 1 to 12 m in indoor environment, inside a box (rain sheltered cabinet), placed in tropical humid marine-urban climate, as a part of Gulf of Mexico. The corrosion aggressiveness of box has been classified as a very high corrosive, based on the monitored chlorides and SO2 deposition rates, and the Temperature/Relative Humidity air daily complex. The annual mass increasing of nickel is approximately twice higher than its values of lass loss (C). the relation between nickel mass loss or increasing and time of wetness (t) of metal surface is linear and does not obey the power equation C=A t''n, which has be found for tin. The SEM images reveal a localized corrosion on nickel and tin surfaces. XRD detects the formation of SnCl2.H2O as a corrosion product. Within the time on the tin surface appear black spots, considered as organic material. (Author) 26 refs

  19. Hot corrosion of TD nickel and TD nickel chromium in a high velocity gas stream.

    Science.gov (United States)

    Sanders, W. A.; Probst, H. B.

    1971-01-01

    Results of cyclical tests of TD nickel (2% thoria-dispersed nickel) and TD nickel chromium (2% thoria-dispersed nickel-20% chromium alloy) 1.5 mm (60 mil) sheet specimens for susceptibility to hot corrosion in a Mach 0.5 gas stream of Jet A-1 fuel combustion products containing 2 ppm sea salt. Tests as long as 500 one-hour cycles between room temperature and specimen hot zone temperatures of 899 C (1650 F), 982 C (1800 F), and 1149 C (2100 F) were performed. Evidence of hot corrosion was found for both materials in the 899 C (1650 F) and 982 C (1800 F) tests, but not at 1149 C (2100 F). It was concluded that because of high metal thickness losses neither alloy in sheet form is suitable for long-time engine application in a hot corrosion environment at temperatures of 982 C (1800 F) or above.

  20. Effects of cadmium on nickel electrodes in nickel-cadmium cells

    International Nuclear Information System (INIS)

    Nickel cadmium battery cells containing nicel electrodes that are not treated with cadmium during the manufacturing process have a history of performance variability and capacity problems in various cell test programs. In this work cadmium additions to the nickel electrode are examined to determine the effects on the fundamental electrochemical processes occurring at this electrode. The results indicate that cadmium treatments improve recharge efficiency by increasing the potential required for oxygen evolution from the nickel electrode, thus decreasing the overcharge rate at a given voltage and allowing the nickel electrode to attain a higher state of charge. The effects of cadmium treatment become particularly important for stable cell operation at temperatures above 10 C, and for capacity maintenance under conditions of long term, low rate trickle charge

  1. Reduced frequency of nickel allergy upon oral nickel contact at an early age

    DEFF Research Database (Denmark)

    Van Hoogstraten, I M; Andersen, Klaus Ejner; Von Blomberg, B M;

    1991-01-01

    an effective way to prevent undesired T cell-mediated immune functions, such as playing a role in allograft reaction, autoimmune and allergic diseases. In the present study allergic contact hypersensitivity (ACH) to nickel, currently presenting the most frequent contact allergy in man, was chosen to...... establish the feasibility of oral prevention of undesired T cell-mediated immunity in man. Potentially tolerizing (oral nickel contacts via orthodontic braces) as well as sensitizing (ear piercing) events were studied retrospectively in 2176 patients attending nine European patch test clinics. Patients were...... interviewed by means of a confidential questionnaire. The results show that ear piercing strongly favoured development of nickel ACH. More importantly, patients having had oral contacts with nickel-releasing appliances (dental braces) at an early age, but only if prior to ear piercing, showed a reduced...

  2. Sequential desorption energy of hydrogen from nickel clusters

    Energy Technology Data Exchange (ETDEWEB)

    Deepika,; Kumar, Rakesh, E-mail: rakesh@iitrpr.ac.in [Department of Physics, Indian Institute of Technology Ropar, Rupnagar-140001 (India); R, Kamal Raj. [Indian Institute of Science Education and Research Kolkata, Mohanpur-741246 (India); Kumar, T. J. Dhilip [Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar-140001 (India)

    2015-06-24

    We report reversible Hydrogen adsorption on Nickel clusters, which act as a catalyst for solid state storage of Hydrogen on a substrate. First-principles technique is employed to investigate the maximum number of chemically adsorbed Hydrogen molecules on Nickel cluster. We observe a maximum of four Hydrogen molecules adsorbed per Nickel atom, but the average Hydrogen molecules adsorbed per Nickel atom decrease with cluster size. The dissociative chemisorption energy per Hydrogen molecule and sequential desorption energy per Hydrogen atom on Nickel cluster is found to decrease with number of adsorbed Hydrogen molecules, which on optimization may help in economical storage and regeneration of Hydrogen as a clean energy carrier.

  3. Sequential desorption energy of hydrogen from nickel clusters

    International Nuclear Information System (INIS)

    We report reversible Hydrogen adsorption on Nickel clusters, which act as a catalyst for solid state storage of Hydrogen on a substrate. First-principles technique is employed to investigate the maximum number of chemically adsorbed Hydrogen molecules on Nickel cluster. We observe a maximum of four Hydrogen molecules adsorbed per Nickel atom, but the average Hydrogen molecules adsorbed per Nickel atom decrease with cluster size. The dissociative chemisorption energy per Hydrogen molecule and sequential desorption energy per Hydrogen atom on Nickel cluster is found to decrease with number of adsorbed Hydrogen molecules, which on optimization may help in economical storage and regeneration of Hydrogen as a clean energy carrier

  4. A simple nickel activation process for electroless nickel-phosphorus plating on carbon fiber

    OpenAIRE

    Tingguo Yan; Leihong Li; Lijuan Wang

    2013-01-01

    A new nickel activation process was developed for metalizing the carbon fiber (CF) surface with electroless nickel plating. The oxidation and activation processes were examined using X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectrometry (EDS), and X-ray Diffractometry (XRD). XPS analysis showed that HNO3 oxidation improved the O/C ratio of the CF surface, which resulted in an increase in the amount of oxygen-containing groups. As acti...

  5. Hydrogen embrittlement in nickel-hydrogen cells

    Science.gov (United States)

    Gross, Sidney

    1989-01-01

    It was long known that many strong metals can become weakened and brittle as the result of the accumulation of hydrogen within the metal. When the metal is stretched, it does not show normal ductile properties, but fractures prematurely. This problem can occur as the result of a hydrogen evolution reaction such as corrosion or electroplating, or due to hydrogen in the environment at the metal surface. High strength alloys such as steels are especially susceptible to hydrogen embrittlement. Nickel-hydrogen cells commonly use Inconel 718 alloy for the pressure container, and this also is susceptible to hydrogen embrittlement. Metals differ in their susceptibility to embrittlement. Hydrogen embrittlement in nickel-hydrogen cells is analyzed and the reasons why it may or may not occur are discussed. Although Inconel 718 can display hydrogen embrittlement, experience has not identified any problem with nickel-hydrogen cells. No hydrogen embrittlement problem is expected with the 718 alloy pressure container used in nickel-hydrogen cells.

  6. Large Scale Evaluation fo Nickel Aluminide Rolls

    Energy Technology Data Exchange (ETDEWEB)

    None

    2005-09-01

    This completed project was a joint effort between Oak Ridge National Laboratory and Bethlehem Steel (now Mittal Steel) to demonstrate the effectiveness of using nickel aluminide intermetallic alloy rolls as part of an updated, energy-efficient, commercial annealing furnace system.

  7. Important Parameters and Applications for Nickel Electroforming

    DEFF Research Database (Denmark)

    Tang, Peter Torben; Benzon, Michael Eis; Rasmussen, J.P.; Fontenay, Frank Le Sage De

    Electroforming is versatile process that is being used more and more, although the basic idea is almost a hundred years old. This paper will concentrate on the important mechanical properties and electrolyte parameters of nickel electroforming. Electrolyte parameters such as current density, p...

  8. Nickel Complexes of Thiosemicarbazone Derivatives of Lawsone

    OpenAIRE

    Sanjay Gaikwad

    2013-01-01

    Thiosemicarbazone derivative at 1 position of the Lawsone ( 2-hydroxy-1,4-naphthalenedione ) i.e. 1-TSCND is an important derivative, Which possesses a powerful chelating ability, appreciable analytical utility and significant biological activity[1]. Its Nickel (II) complex is newly reported here

  9. Surface magnetism in iron, cobalt, and nickel

    DEFF Research Database (Denmark)

    Alde´n, M.; Mirbt, S.; Skriver, Hans Lomholt;

    1992-01-01

    We have calculated magnetic moments, work functions, and surface energies for several of the most closely packed surfaces of iron, cobalt, and nickel by means of a spin-polarized Green’s-function technique based on the linear muffin-tin orbitals method within the tight-binding and atomic sphere...

  10. Growth of hollow nickel fluoride whiskers

    International Nuclear Information System (INIS)

    Hollow nickel fluoride whiskers have been obtained by condensation from the vapor phase onto a platinum substrate in a flow of hydrogen fluoride. Crystals up to 5 mm in length have a square cross section with a 300 ± 30-μm side. The wall thickness is 85 ± 20 μm.

  11. Ir Spectroscopy and Nickel (II) Hexammines

    Science.gov (United States)

    Reedijk, J.; And Others

    1975-01-01

    Describes an experiment, for the general chemistry laboratory, intended to introduce the student to infrared spectroscopy. After being introduced to the theory of molecular vibrations on an elementary level, each student receives a list of 5-7 nickel (II) ammines to be prepared, analyzed and characterized by infrared spectoscopy. (MLH)

  12. Nickel Complexes of Thiosemicarbazone Derivatives of Lawsone

    Directory of Open Access Journals (Sweden)

    Sanjay Gaikwad

    2013-06-01

    Full Text Available Thiosemicarbazone derivative at 1 position of the Lawsone ( 2-hydroxy-1,4-naphthalenedione i.e. 1-TSCND is an important derivative, Which possesses a powerful chelating ability, appreciable analytical utility and significant biological activity[1]. Its Nickel (II complex is newly reported here

  13. Nickel adsorption on chalk and calcite

    DEFF Research Database (Denmark)

    Belova, Dina Alexandrovna; Lakshtanov, Leonid; Carneiro, J.F.;

    2014-01-01

    Nickel uptake from solution by two types of chalk and calcite was investigated in batch sorption studies. The goal was to understand the difference in sorption behavior between synthetic and biogenic calcite. Experiments at atmospheric partial pressure of CO2, in solutions equilibrated with calcite...

  14. Linear Genetic Programming for Prediction of Nickel Recovery from Spent Nickel Catalyst

    Directory of Open Access Journals (Sweden)

    Mon E. Ossman

    2010-01-01

    Full Text Available Problem statement: In this study Linear Genetic Programming (LGP and statistical regression are used in predicting Current Efficiency (CE of Electro deposition cell used for recovery of nickel from spent nickel catalyst. Approach: The Nickel electro deposition from spent catalyst leachate solutions was studied to determine the effect of the operative conditions such as nickel concentration, temperature, current density and time on the CE of the unit cell. Results: For this purpose, LGP and regression models were calibrated with training sets and validated by testing sets. Additionally, the robustness of the proposed LGP and regression models were evaluated by experimental data, which are used neither in training nor at testing stage. The results showed that both techniques predicted the CE data in quite good agreement with the observed ones and the predictions of LGP are challenging. Conclusion/Recommendations: The performance of LGP, which was moderately better than statistical regression, is very promising and hence supports the use of LGP in simulating the electro deposition of Nickel from spent Nickel catalyst.

  15. Stimulated Black Hole Evaporation

    CERN Document Server

    Spaans, Marco

    2016-01-01

    Black holes are extreme expressions of gravity. Their existence is predicted by Einstein's theory of general relativity and is supported by observations. Black holes obey quantum mechanics and evaporate spontaneously. Here it is shown that a mass rate $R_f\\sim 3\\times 10^{-8} (M_0/M)^{1/2}$ $M_0$ yr$^{-1}$ onto the horizon of a black hole with mass $M$ (in units of solar mass $M_0$) stimulates a black hole into rapid evaporation. Specifically, $\\sim 3 M_0$ black holes can emit a large fraction of their mass, and explode, in $M/R_f \\sim 3\\times 10^7 (M/M_0)^{3/2}$ yr. These stimulated black holes radiate a spectral line power $P \\sim 2\\times 10^{39} (M_0/M)^{1/2}$ erg s$^{-1}$, at a wavelength $\\lambda \\sim 3\\times 10^5 (M/M_0)$ cm. This prediction can be observationally verified.

  16. Astrophysical black holes

    CERN Document Server

    Gorini, Vittorio; Moschella, Ugo; Treves, Aldo; Colpi, Monica

    2016-01-01

    Based on graduate school lectures in contemporary relativity and gravitational physics, this book gives a complete and unified picture of the present status of theoretical and observational properties of astrophysical black holes. The chapters are written by internationally recognized specialists. They cover general theoretical aspects of black hole astrophysics, the theory of accretion and ejection of gas and jets, stellar-sized black holes observed in the Milky Way, the formation and evolution of supermassive black holes in galactic centers and quasars as well as their influence on the dynamics in galactic nuclei. The final chapter addresses analytical relativity of black holes supporting theoretical understanding of the coalescence of black holes as well as being of great relevance in identifying gravitational wave signals. With its introductory chapters the book is aimed at advanced graduate and post-graduate students, but it will also be useful for specialists.

  17. Cosmic Black Holes

    OpenAIRE

    Ahn, Eun-Joo; Cavaglia, Marco

    2003-01-01

    Production of high-energy gravitational objects is a common feature of gravitational theories. The primordial universe is a natural setting for the creation of black holes and other nonperturbative gravitational entities. Cosmic black holes can be used to probe physical properties of the very early universe which would usually require the knowledge of the theory of quantum gravity. They may be the only tool to explore thermalisation of the early universe. Whereas the creation of cosmic black ...

  18. The New Black

    OpenAIRE

    Lettman-Hicks, Sharon

    2014-01-01

    The New Black is a documentary that tells the story of how the African American community is grappling with the gay rights issue in light of the recent gay marriage movement and the fight over Civil Rights. The film documents activities, families and clergy on both sides of the campaign to legalize gay marriage and examines homophobia in the Black community's institutional pillar, the Black church, and reveals the Christian right wing's strategy of exploiting this phenomenon in order to pursu...

  19. Black branes as piezoelectrics.

    Science.gov (United States)

    Armas, Jay; Gath, Jakob; Obers, Niels A

    2012-12-14

    We find a realization of linear electroelasticity theory in gravitational physics by uncovering a new response coefficient of charged black branes, exhibiting their piezoelectric behavior. Taking charged dilatonic black strings as an example and using the blackfold approach we measure their elastic and piezolectric moduli. We also use our results to draw predictions about the equilibrium condition of charged dilatonic black rings in dimensions higher than six. PMID:23368298

  20. Kerr black string flow

    Directory of Open Access Journals (Sweden)

    Meng Sun

    2015-08-01

    Full Text Available We give a general illumination of a rotating black string falling into a rotating horizon in dimension D=5. It is a configuration of one smooth intersection between these two objects when the spacetime is axisymmetric and in the limit that the thickness of the black hole is much larger than the thickness of the black string. Following this configuration, we further extend them to the rotating and charged flows.

  1. Epicutaneous exposure to nickel induces nickel allergy in mice via a MyD88-dependent and interleukin-1-dependent pathway

    DEFF Research Database (Denmark)

    Vennegaard, Marie T; Dyring-Andersen, Beatrice; Skov, Lone; Nielsen, Morten M; Schmidt, Jonas D; Bzorek, Michael; Poulsen, Steen S; Thomsen, Allan Randrup; Andersen, Anders Woetmann; Thyssen, Jacob P; Johansen, Jeanne D; Odum, Niels; Menné, Torkil; Geisler, Carsten; Bonefeld, Charlotte M

    2014-01-01

    nickel in the epidermis, and induces nickel allergy in mice. The allergic response to nickel following epicutaneous exposure is MyD88-dependent and interleukin (IL)-1 receptor-dependent, but independent of toll-like receptor (TLR)-4. CONCLUSION: This new model for nickel allergy that reflects...... epicutaneous exposure to nickel in humans shows that nickel allergy is dependent on MyD88 and IL-1 receptor signalling, but independent of TLR4....

  2. Aqueous Corrosion Characteristics of Nickel Aluminides

    International Nuclear Information System (INIS)

    The aqueous corrosion characteristics of three nickel aluminides were studied by using (a) immersion corrosion test and (b) cyclic anodic polarization measurements. The immersion tests were conducted in 15 different solutions at 25 .deg. C and 95 .deg. C. The nickel aluminides were found to have good corrosion resistance in inorganic acids, organic acids and basic solutions 25 .deg. C except at a higher concentration of hydrochloric acid in ferric chloride solution at the temperature. All three nickel aluminides were suitably resistant to corrosion in the organic acids (oxalic acid, acetic acid), sodium chloride solution, and bases (sodium hydoxide, ammonium hydroxide) at 95 .deg. C. The cyclic anodic polarization curves were developed in N2-deaerated solution at 25 .deg. C and 95 .deg. C. In addition, open-circuit corrosion potentials were determined for the solutions in the aerated condition at 25 .deg. C to compare with the anodic curves. At 25 .deg. C, although all materials exhibited active-passive behavior in all solutions except the hydrofluoric acid, at Ecorr(aerated), passive corrosion was only indicated for the acetic acid, sodium hydroxide, and sodium chloride solutions. Nevertheless, in all cases, the predicted dissolution rates were consistent with immersion test results. Hysteresis loops indicating susceptibility to localized corrosion were observed in 0.6M sodium chloride(pH=7) solution. At 95 .deg. C, active-passive behavior was demonstrated in the acetic acid, sodium chloride, and to a limited extent in the nitric acid: but only active behavior was shown in the sulfuric and hydrofluoric acids. From the above results, it was noted that anodic dissolution of nickel aluminides significantly increased with increasing temperature and that the Cr-containing compositions had better corrosion resistance in several solutions than the Cr-free composition. Prior manufacturing procedures, i.e., casting and powder metallurgy processes did not appear to

  3. Microfibrous nickel substrates and electrodes for battery system applications

    Science.gov (United States)

    Zhu, Wenhua H.; Durben, Peter J.; Tatarchuk, Bruce J.

    The use of microfibrous nickel substrates is advantageous for increasing the surface area available for the deposition of active material and reducing the substrate weight and consequently, yields a higher specific capacity for nickel hydroxide electrodes. Porous, microfiber-based nickel substrates were produced by sintering a composite preform. The preforms, consisting of nickel fibers with diameters as small as 2 μm and cellulose fibers, were formed using a papermaking process. The fabricated nickel electrodes that included a supporting nickel mesh in the substrate tested in a 26% KOH half-cell delivered a specific capacity of more than 250 mAh/g of the electrode weight (i.e. fibrous substrate, nickel mesh, and active material) at a 1.0 C discharge rate. An Auburn electrode without a nickel mesh tested in the same half-cell attained a higher specific capacity of 268 mAh/g at a 1.37 C discharge rate. The substrates used in these electrodes had porosities of 95-97%, and greatly improved the specific capacity of the nickel electrode. With the use of the microfibrous electrode, improved specific energies of nickel-based cell and battery designs are possible. When assembled in a nickel-hydrogen (Ni-H 2) boilerplate cell, the specific capacity of nearly 230 mAh/g was observed for the nickel electrode at a 0.5 C rate during the 127th cycle test. The results of high specific capacity and quick rise in utilization of microfibrous nickel hydroxide electrodes make these electrodes good candidates for significantly improving the energy density and performance of nickel-hydrogen cells.

  4. Ten shades of black

    CERN Document Server

    Hod, Shahar

    2015-01-01

    The holographic principle has taught us that, as far as their entropy content is concerned, black holes in $(3+1)$-dimensional curved spacetimes behave as ordinary thermodynamic systems in flat $(2+1)$-dimensional spacetimes. In this essay we point out that the opposite behavior can also be observed in black-hole physics. To show this we study the quantum Hawking evaporation of near-extremal Reissner-Nordstr\\"om black holes. We first point out that the black-hole radiation spectrum departs from the familiar radiation spectrum of genuine $(3+1)$-dimensional perfect black-body emitters. In particular, the would be black-body thermal spectrum is distorted by the curvature potential which surrounds the black hole and effectively blocks the emission of low-energy quanta. Taking into account the energy-dependent gray-body factors which quantify the imprint of passage of the emitted radiation quanta through the black-hole curvature potential, we reveal that the $(3+1)$-dimensional black holes effectively behave as p...

  5. Evidence for black holes.

    Science.gov (United States)

    Begelman, Mitchell C

    2003-06-20

    Black holes are common objects in the universe. Each galaxy contains large numbers-perhaps millions-of stellar-mass black holes, each the remnant of a massive star. In addition, nearly every galaxy contains a supermassive black hole at its center, with a mass ranging from millions to billions of solar masses. This review discusses the demographics of black holes, the ways in which they interact with their environment, factors that may regulate their formation and growth, and progress toward determining whether these objects really warp spacetime as predicted by the general theory of relativity. PMID:12817138

  6. Black hole statistics

    International Nuclear Information System (INIS)

    The quantum statistics of charged, extremal black holes is investigated beginning with the hypothesis that the quantum state is a functional on the space of closed three-geometries, with each black hole connected to an oppositely charged black hole through a spatial wormhole. From this starting point a simple argument is given that a collection of extremal black holes obeys neither Bose nor Fermi statistics. Rather, they obey an exotic variety of particle statistics known as ''infinite statistics'' which resembles that of distinguishable particles and is realized by a q deformation of the quantum commutation relations

  7. Antigravity and black holes

    CERN Document Server

    Hajdukovic, D

    2006-01-01

    We speculate about impact of antigravity (i.e. gravitational repulsion between matter and antimatter) on the creation and emission of particles by a black hole. If antigravity is present a black hole made of matter may radiate particles as a black body, but this shouldn't be true for antiparticles. It may lead to radical change of radiation process predicted by Hawking and should be taken into account in preparation of the attempt to create and study mini black holes at CERN. Gravity, including antigravity is more than ever similar to electrodynamics and such similarity with a successfully quantized interaction may help in quantization of gravity.

  8. Deforming regular black holes

    CERN Document Server

    Neves, J C S

    2015-01-01

    In this work, we have deformed regular black holes which possess a general mass term described by a function which generalizes the Bardeen and Hayward mass terms. Using linear constraints in the energy-momentum tensor, the solutions are either regular or singular. That is, with this approach, it is possible to generate singular black holes from regular black holes and vice versa. Moreover, contrary to the Bardeen and Hayward regular solutions, the regular deformed metrics may violate the weak energy condition despite the presence of the spherical symmetry. Some comments on accretion of deformed black holes in cosmological scenarios are made.

  9. Black stain - a review.

    Science.gov (United States)

    Ronay, Valerie; Attin, Thomas

    2011-01-01

    The purpose of this review was to summarise the fundamentals about black stain, its diagnosis and possible differential diagnoses as well as its microbiology and therapy. In addition, various studies investigating the relationship between black stain and dental caries are examined. Many studies report lower caries prevalence in children with black stain, but this finding could not be confirmed by all authors. Also, a negative relation between degree of staining and caries severity has been described. Reasons for these results are not yet clear but it was speculated that they are related to the specific oral microflora described in black stain-affected individuals. PMID:21594205

  10. "Black Capitalism": Toward Controlled Development of Black America

    Science.gov (United States)

    Wright, Robert E.

    1969-01-01

    Argues in favor of the connotation of the term "Black capitalism as the accumulation of capital resources by the Black people in a collective fashion for the benefit of the masses of Black people. (RJ)

  11. Black holes and beyond

    International Nuclear Information System (INIS)

    Belief in the existence of black holes is the ultimate act of faith for a physicist. First suggested by the English clergyman John Michell in the year 1784, the gravitational pull of a black hole is so strong that nothing - not even light - can escape. Gravity might be the weakest of the fundamental forces but black-hole physics is not for the faint-hearted. Black holes present obvious problems for would-be observers because they cannot, by definition, be seen with conventional telescopes - although before the end of the decade gravitational-wave detectors should be able to study collisions between black holes. Until then astronomers can only infer the existence of a black hole from its gravitational influence on other matter, or from the X-rays emitted by gas and dust as they are dragged into the black hole. However, once this material passes through the 'event horizon' that surrounds the black hole, we will never see it again - not even with X-ray specs. Despite these observational problems, most physicists and astronomers believe that black holes do exist. Small black holes a few kilometres across are thought to form when stars weighing more than about two solar masses collapse under the weight of their own gravity, while supermassive black holes weighing millions of solar masses appear to be present at the centre of most galaxies. Moreover, some brave physicists have proposed ways to make black holes - or at least event horizons - in the laboratory. The basic idea behind these 'artificial black holes' is not to compress a large amount of mass into a small volume, but to reduce the speed of light in a moving medium to less than the speed of the medium and so create an event horizon. The parallels with real black holes are not exact but the experiments could shed new light on a variety of phenomena. The first challenge, however, is to get money for the research. One year on from a high-profile meeting on artificial black holes in London, for instance, the UK

  12. Corrosion cracking of high-strength structural steels at large depths in the Black Sea

    International Nuclear Information System (INIS)

    The results of field tests of structural chromium-nickel-molybdenum steels of various strength capacity for their tendency to corrosion cracking in the Black sea water, containing hydrogen sulfide at high depths, are presented. Comparison with the laboratory test data is also carried out and certain peculiarities, revealed thereby, are discussed. It is shown, that hydrogen sulfide if biological origin is more aggressive as compared to the chemically obtained one. The rigidity of the hydrogen sulfide at the deep horizons of the Black sea is unprecedented in comparison with any other region of the World ocean

  13. Rotating Brane World Black Holes

    OpenAIRE

    Modgil, Moninder Singh; Panda, Sukanta; Sengupta, Gautam

    2001-01-01

    A five dimensional rotating black string in a Randall-Sundrum brane world is considered. The black string intercepts the three brane in a four dimensional rotating black hole. The geodesic equations and the asymptotics in this background are discussed.

  14. Electrodeposition of black chromium thin films from trivalent chromium-ionic liquid solution

    OpenAIRE

    Eugénio, S.; Vilar, Rui; C. M. Rangel; Baskaran, I.

    2009-01-01

    In the present study, black chromium thin films were electrodeposited from a solution of 1-butyl-3- methylimidazolium tetrafluoroborate ([BMIm][BF4] ionic liquid containing trivalent chromium (Cr(III)). Homogeneous and well adherent coatings have been obtained on nickel, copper and stainless steel substrates. The nucleation and growth of the films were investigated by cyclic voltammetry and current-density/time transient techniques. SEM/EDS, XPS and XRD were used to study the morphology, chem...

  15. Investigation of surface composition of electrodeposited black chrome coatings by X-ray photoelectron spectroscopy

    OpenAIRE

    Anandan, C; Grips, VKW; Rajam, KS; Jayaram, V; P Bera

    2002-01-01

    : Solar selective black chromium coating was electrodeposited on pre-treated electroformed nickel substrates from a hexavalent chromium containing bath. The composition of the film was investigated before and after annealing at 400 degreesC for different durations. In the as-deposited condition. the surface of the film was found to have trivalent chromium hydroxide and chromium in the chromate form contrary to previous studies which report the presence of hydroxides and metallic chromium. How...

  16. The GENIALL process for generation of nickel-iron alloys from nickel ores or mattes

    International Nuclear Information System (INIS)

    A new process, called GENIALL (acronym of Generation of Nickel Alloys), for nickel recovery as ferronickel alloys from ores or mattes without previous smelting is presented in this paper. Its core technology is a new electrolytic concept, the ROSEL cell, for electrowinning of nickel-iron alloys from concentrated chloride solutions. In the GENIALL Process the substitution of iron-based solid wastes as jarosite, goethite or hematite, by saleable ferronickel plates provides both economic and environmental attractiveness. Another advantage is that no associated sulfuric acid plant is required. The process starts with leaching of the raw material (ores or mattes) with a solution of ferric chloride. The leachate liquor is purified by conventional methods like cementation or solvent extraction, to remove impurities or separate by-products like copper and cobalt. The purified solution, that contains a mixture of ferrous and nickel chlorides is fed to the cathodic compartment of the electrowinning cell, where nickel and ferrous ions are reduced together to form an alloy. Simultaneously, ferrous chloride is oxidized to ferric chloride in the anodic compartment, from where it is recycled to the leaching stage. The new electrolytic equipment has been developed and scaled up from laboratory to pilot prototypes with commercial size electrodes of 1 m2. Process operating conditions have been established in continuous runs at bench and pilot plant scale. The technology has shown a remarkable capacity to produce nickel-iron alloys of a wide range of compositions, from 10% to 80% nickel, just by adjusting the operating parameters. This emerging technology could be implemented in many processes in which iron and other non-ferrous metals are harmful impurities to be removed, or valuable metals to be recovered as a marketable iron alloy. Other potential applications of this technology are regeneration of spent etching liquors, and iron removal from aqueous effluents. (author)

  17. Evolution of massive black holes

    OpenAIRE

    Volonteri, Marta

    2007-01-01

    Supermassive black holes are nowadays believed to reside in most local galaxies. Accretion of gas and black hole mergers play a fundamental role in determining the two parameters defining a black hole: mass and spin. I briefly review here some of the physical processes that are conducive to the evolution of the massive black hole population. I'll discuss black hole formation processes that are likely to place at early cosmic epochs, and how massive black hole evolve in a hierarchical Universe...

  18. Pyrolytic carbon coated black silicon

    OpenAIRE

    Shah, Ali; Stenberg, Petri; Karvonen, Lasse; Ali, Rizwan; Honkanen, Seppo; Lipsanen, Harri; Peyghambarian, N.; Kuittinen, Markku; Svirko, Yuri; Kaplas, Tommi

    2016-01-01

    Carbon is the most well-known black material in the history of man. Throughout the centuries, carbon has been used as a black material for paintings, camouflage, and optics. Although, the techniques to make other black surfaces have evolved and become more sophisticated with time, carbon still remains one of the best black materials. Another well-known black surface is black silicon, reflecting less than 0.5% of incident light in visible spectral range but becomes a highly reflecting surface ...

  19. Nickel recycling in the United States in 2004

    Science.gov (United States)

    Goonan, Thomas G.

    2009-01-01

    As one of a series of reports that describe the recycling of metal commodities in the United States, this report discusses the flow of nickel from production through distribution and use, with particular emphasis on the recycling of industrial scrap (new scrap) and used products (old scrap) in 2004. This materials flow study includes a description of nickel supply and demand for the United States to illustrate the extent of nickel recycling and to identify recycling trends. Understanding how materials flow from a source through disposition can aid in improving the management of natural resource delivery systems. In 2004, the old scrap recycling efficiency for nickel was estimated to be 56.2 percent. In 2004, nickel scrap consumption in the United States was as follows: new scrap containing 13,000 metric tons (t) of nickel (produced during the manufacture of products), 12 percent; and old scrap containing 95,000 t of nickel (articles discarded after serving a useful purpose), 88 percent. The recycling rate for nickel in 2004 was 40.9 percent, and the percentage of nickel in products attributed to nickel recovered from nickel-containing scrap was 51.6 percent. Furthermore, U.S. nickel scrap theoretically generated in 2004 had the following distribution: scrap to landfills, 24 percent; recovered and used scrap, 50 percent; and unaccounted for scrap, 26 percent. Of the 50 percent of old scrap generated in the United States that was recovered and then used in 2004, about one-third was exported and two-thirds was consumed in the domestic production of nickel-containing products.

  20. Structural transformation of nickel hydroxide films during anodic oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Crocker, R.W.; Muller, R.H.

    1992-05-01

    The transformation of anodically formed nickel hydroxide/oxy-hydroxide electrodes has been investigated. A mechanism is proposed for the anodic oxidation reaction, in which the reaction interface between the reduced and oxidized phases of the electrode evolves in a nodular topography that leads to inefficient utilization of the active electrode material. In the proposed nodular transformation model for the anodic oxidation reaction, nickel hydroxide is oxidized to nickel oxy-hydroxide in the region near the metal substrate. Since the nickel oxy-hydroxide is considerably more conductive than the surrounding nickel hydroxide, as further oxidation occurs, nodular features grow rapidly to the film/electrolyte interface. Upon emerging at the electrolyte interface, the reaction boundary between the nickel hydroxide and oxy-hydroxide phases spreads laterally across the film/electrolyte interface, creating an overlayer of nickel oxy-hydroxide and trapping uncharged regions of nickel hydroxide within the film. The nickel oxy-hydroxide overlayer surface facilitates the oxygen evolution side reaction. Scanning tunneling microscopy of the electrode in its charged state revealed evidence of 80 {endash} 100 Angstrom nickel oxy-hydroxide nodules in the nickel hydroxide film. In situ spectroscopic ellipsometer measurements of films held at various constant potentials agree quantitatively with optical models appropriate to the nodular growth and subsequent overgrowth of the nickel oxy-hydroxide phase. A two-dimensional, numerical finite difference model was developed to simulate the current distribution along the phase boundary between the charged and uncharged material. The model was used to explore the effects of the physical parameters that govern the electrode behavior. The ratio of the conductivities of the nickel hydroxide and oxy-hydroxide phases was found to be the dominant parameter in the system.

  1. Carbon black recovery

    International Nuclear Information System (INIS)

    A process and apparatus for recovering carbon black from hot smoke which comprises passing the smoke through a cyclone separation zone following cooling, then through aggregate filter beds and regeneration of filter beds with clean off-gas which is recycled to the carbon black reaction zone as quench

  2. Noncommutative Singular Black Holes

    International Nuclear Information System (INIS)

    In this paper, applying the method of coordinate coherent states to describe a noncommutative model of Vaidya black holes leads to an exact (t - r) dependence of solution in terms of the noncommutative parameter σ. In this setup, there is no black hole remnant at long times.

  3. Noncommutative Singular Black Holes

    Science.gov (United States)

    Hamid Mehdipour, S.

    2010-11-01

    In this paper, applying the method of coordinate coherent states to describe a noncommutative model of Vaidya black holes leads to an exact (t — r) dependence of solution in terms of the noncommutative parameter σ. In this setup, there is no black hole remnant at long times.

  4. Black holes matter

    DEFF Research Database (Denmark)

    Kragh, Helge Stjernholm

    2016-01-01

    Review essay, Marcia Bartusiak, Black Hole: How an Idea Abandoned by Newtonians, Hated by Einstein, and Gambled On by Hawking Became Loved (New Haven: Yale University Press, 2015).......Review essay, Marcia Bartusiak, Black Hole: How an Idea Abandoned by Newtonians, Hated by Einstein, and Gambled On by Hawking Became Loved (New Haven: Yale University Press, 2015)....

  5. Black holes in inflation

    Science.gov (United States)

    Bousso, R.; Hawking, S. W.

    1997-08-01

    We summarise recent work on the quantum production of black holes in the inflationary era. We describe, in simple terms, the Euclidean approach used, and the results obtained both for the pair creation rate and for the evolution of the black holes.

  6. Scattering by Black Holes

    CERN Document Server

    Andersson, N

    2000-01-01

    This is a chapter on Black-hole Scattering that was commissioned for an Encyclopaedia on Scattering edited by Pike and Sabatier, to be published by Academic Press. The chapter surveys wave propagation in black-hole spacetimes, diffraction effects in wave scattering, resonances, quasinormal modes and related topics.

  7. Black Craftsmen Through History.

    Science.gov (United States)

    Myers, Robin

    This report traces the evolution of the black craftsmen from ancient Egypt to the present. Special attention is given to the restricted use of black craftsmen under slavery, and the added problems they faced after being freed. Business and union discimination is described, along with recent government and private efforts to achieve equal…

  8. Black Hole Dynamic Potentials

    Indian Academy of Sciences (India)

    Koustubh Ajit Kabe

    2012-09-01

    In the following paper, certain black hole dynamic potentials have been developed definitively on the lines of classical thermodynamics. These potentials have been refined in view of the small differences in the equations of the laws of black hole dynamics as given by Bekenstein and those of thermodynamics. Nine fundamental black hole dynamical relations have been developed akin to the four fundamental thermodynamic relations of Maxwell. The specific heats , and , have been defined. For a black hole, these quantities are negative. The d equation has been obtained as an application of these fundamental relations. Time reversible processes observing constancy of surface gravity are considered and an equation connecting the internal energy of the black hole , the additional available energy defined as the first free energy function , and the surface gravity , has been obtained. Finally as a further application of the fundamental relations, it has been proved for a homogeneous gravitational field in black hole space times or a de Sitter black hole that $C_{\\Omega,\\Phi}-C_{J,Q}=\\kappa \\left[\\left(\\dfrac{\\partial J}{\\partial \\kappa}\\right)_{\\Omega,\\Phi}\\left(\\dfrac{\\partial \\Omega}{\\partial \\kappa}\\right)_{J,Q}+\\left(\\dfrac{\\partial Q}{\\partial \\kappa}\\right)_{\\Omega,\\Phi}\\left(\\dfrac{\\partial\\Phi}{\\partial \\kappa}\\right)_{J,Q}\\right]$. This is dubbed as the homogeneous fluid approximation in context of the black holes.

  9. Fluctuating Black Hole Horizons

    CERN Document Server

    Mei, Jianwei

    2013-01-01

    In this paper we treat the black hole horizon as a physical boundary to the spacetime and study its dynamics following from the Gibbons-Hawking-York boundary term. Using the Kerr black hole as an example we derive an effective action that describes, in the large wave number limit, a massless Klein-Gordon field living on the average location of the boundary. Complete solutions can be found in the small rotation limit of the black hole. The formulation suggests that the boundary can be treated in the same way as any other matter contributions. In particular, the angular momentum of the boundary matches exactly with that of the black hole, suggesting an interesting possibility that all charges (including the entropy) of the black hole are carried by the boundary. Using this as input, we derive predictions on the Planck scale properties of the boundary.

  10. Amorphous nickel boride membrane on a platinum-nickel alloy surface for enhanced oxygen reduction reaction

    Science.gov (United States)

    He, Daping; Zhang, Libo; He, Dongsheng; Zhou, Gang; Lin, Yue; Deng, Zhaoxiang; Hong, Xun; Wu, Yuen; Chen, Chen; Li, Yadong

    2016-08-01

    The low activity of the oxygen reduction reaction in polymer electrolyte membrane fuel cells is a major barrier for electrocatalysis, and hence needs to be optimized. Tuning the surface electronic structure of platinum-based bimetallic alloys, a promising oxygen reduction reaction catalyst, plays a key role in controlling its interaction with reactants, and thus affects the efficiency. Here we report that a dealloying process can be utilized to experimentally fabricate the interface between dealloyed platinum-nickel alloy and amorphous nickel boride membrane. The coating membrane works as an electron acceptor to tune the surface electronic structure of the platinum-nickel catalyst, and this composite catalyst composed of crystalline platinum-nickel covered by amorphous nickel boride achieves a 27-times enhancement in mass activity relative to commercial platinum/carbon at 0.9 V for the oxygen reduction reaction performance. Moreover, this interactional effect between a crystalline surface and amorphous membrane can be readily generalized to facilitate the 3-times higher catalytic activity of commercial platinum/carbon.

  11. Significantly improved electrochemical hydrogen storage properties of magnesium nickel hydride modified with nano-nickel

    Science.gov (United States)

    Chen, Wei; Zhu, Yunfeng; Yang, Chen; Zhang, Jiguang; Li, Menghuai; Li, Liquan

    2015-04-01

    Magnesium nickel hydride (Mg2NiH4) used as negative electrode material in nickel-metal hydride (Ni-MH) secondary battery is modified by nano-nickel via mechanical milling. In this paper, we systematically investigate the microstructure and electrochemical properties of the modified system with different milling durations. X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM) analyses confirm the amorphous transformation of Mg2Ni-based hydride and a novel NiH0.75 nanocrystalline with a diameter of about 5 nm embedding or covering on the surface of the base particle has been observed. Its formation mechanism and positive effects on electrochemical properties of the Mg2NiH4 have also been elaborated. Electrochemical measurements show that the 5 h milled composite possesses markedly increased discharge capacity up to 896 mAh g-1. With prolonging the milling duration from 5 h to 40 h, the discharge capacity at the 10th cycle increases from 99 mAh g-1 to 359 mAh g-1. Besides, the discharging procedure changes from stepwise processes to one single-step process with increasing the milling duration. Tafel polarization test shows that the nano-nickel modified system exhibits a much better anti-corrosion ability during charging/discharging cycles. Meanwhile, both the charge-transfer reaction on the alloy surface and hydrogen diffusion inside the alloy bulk are enhanced with nano-nickel modification.

  12. Isolation and Characterization of Nickel Uptake by Nickel Resistant Bacterial Isolate (NiRBI)

    Institute of Scientific and Technical Information of China (English)

    JAGDISH S PATEL; PRERNA C PATEL; KIRAN KALIA

    2006-01-01

    Bioremediation technology has gained importance because microbes could be the convenient source of bio-absorption/bioaccumulation of metals from effluent streams. Methods The nickel-resistant bacterial isolates (NiRBI)were selected from various bacterial isolates from industrial effluent and grown in nutrient broth containing different concentrations of nickel sulfate (0.3-3.0 mmol/L) and their capability of accumulating metal from the medium. Results Well-defined growth of NiRBI was observed in the medium containing up to 2.5 mmol/L of nickel. The isolate was identified using 16S rRNA and closely related to Pseudomonas fragi. Maximum accumulation of nickel (0.59 mg/g dry weight of bacterial cells) was observed when NiRBI was grown in media containing 2 mmol/L of nickel. The protein profile of the NiRBI cellular extract by SDS-PAGE showed two metal stress-induced proteins of molecular weight 48 KD and 18 KD with a simultaneous down regulation of four proteins of 46.7 KD, 42.2 KD, 19.7 KD, and 4.0 KD. Conclusion 48 KD and 18 KD proteins play a role in metal resistance mechanism by NiRBI.

  13. Comparison of inorganic inhibitors of copper, nickel and copper-nickels in aqueous lithium bromide solution

    International Nuclear Information System (INIS)

    The electrochemical behavior of copper, nickel and two copper-nickel (Cu90/Ni10 and Cu70/Ni30) alloys in 850 g/L LiBr solution in the absence and presence of three different inorganic inhibitors (chromate CrO42-, molybdate MoO42-, and tetraborate B4O72-) has been studied. Differences in inhibition efficiency are discussed in terms of potentiodynamic and cyclic measurements. The best protection is obtained by adding chromate to the 850 g/L LiBr solution while the inhibition efficiencies of molybdate and tetraborate ions were not markedly high. Very aggressive anions, such as bromides, in the present experimental conditions, notably reduce the action of the less efficient molecules (molybdate and tetraborate), but not that of the most efficient ones (chromate). The results of the investigation show that the inhibiting properties depend on the nickel content in the alloy; this element improves the general corrosion resistance of the material in the sense that it shifts free corrosion potential towards more noble values and density corrosion currents towards lower levels. The nickel content in the alloy also enlarges the passivating region of the materials in chromate and molybdate-containing solution; furthermore it decreases the current passivating values to lower values. Nickel addition improves the localized corrosion resistance in the bromide media

  14. Low carbon manganese-nickel-niobium steel

    International Nuclear Information System (INIS)

    Experimental heats of a low carbon-manganese-0.5% nickel-0.15% niobium steel have been rolled to plates between 13.5 and 50 mm thickness and to a 16 mm hot strip. Various combinations of soaking temperatures form 11000C to 13000C and of finish rolling temperatures between 7100C and 9300C have been investigated. From mechanical properties obtained, one can conclude that the investigated steel composition provides very good properties e.g. for pipe steels X65 to X75. In particular, the toughness at low temperature is outstanding despite relaxed rolling conditions. Metalographic and special investigations such as electron microscopy, texture evaluation and chemical extraction, correlated with applied rolling schedules and the mechanical properties obtained resulted in a comprehensive understanding about the benefits of high niobium metallurgy combined with nickel addition. All practically applied welding processes generated mechanical properties, in particular toughness of the weldment, that meet arctic specifications.(Author)

  15. A nickel-hydrogen bipolar secondary battery

    Science.gov (United States)

    Chireau, R. F.; Berchielli, A. S.

    A study was conducted to test the concept of using bipolar nickel-hydrogen batteries for an energy storage system that would be compatible with both existing and future electrical generation and distribution equipment. The feasibility of a bipolar nickel-hydrogen rechargeable system was investigated with respect to performance characteristics such as charge acceptance, overcharge capability, cell reversal capability, electrolyte management, and cycle life. Peak specific power figures of over 350 W per kilogram were achieved and the specific energy of the bipolar battery was 60 W-hr/kg at the 3 hr rate of discharge. It was concluded that the new energy storage system would be suitable for load-leveling applications.

  16. Polarized Neutron Reflectometry of Nickel Corrosion Inhibitors.

    Science.gov (United States)

    Wood, Mary H; Welbourn, Rebecca J L; Zarbakhsh, Ali; Gutfreund, Philipp; Clarke, Stuart M

    2015-06-30

    Polarized neutron reflectometry has been used to investigate the detailed adsorption behavior and corrosion inhibition mechanism of two surfactants on a nickel surface under acidic conditions. Both the corrosion of the nickel surface and the structure of the adsorbed surfactant layer could be monitored in situ by the use of different solvent contrasts. Layer thicknesses and roughnesses were evaluated over a range of pH values, showing distinctly the superior corrosion inhibition of one negatively charged surfactant (sodium dodecyl sulfate) compared to a positively charged example (dodecyl trimethylammonium bromide) due to its stronger binding interaction with the surface. It was found that adequate corrosion inhibition occurs at significantly less than full surface coverage. PMID:26050787

  17. Thermal conductivity of nanoscale thin nickel films

    Institute of Scientific and Technical Information of China (English)

    YUAN Shiping; JIANG Peixue

    2005-01-01

    The inhomogeneous non-equilibrium molecular dynamics (NEMD) scheme is applied to model phonon heat conduction in thin nickel films. The electronic contribution to the thermal conductivity of the film is deduced from the electrical conductivity through the use of the Wiedemann-Franz law. At the average temperature of T = 300 K, which is lower than the Debye temperature ()D = 450 K,the results show that in a film thickness range of about 1-11 nm, the calculated cross-plane thermal conductivity decreases almost linearly with the decreasing film thickness, exhibiting a remarkable reduction compared with the bulk value. The electrical and thermal conductivities are anisotropic in thin nickel films for the thickness under about 10 nm. The phonon mean free path is estimated and the size effect on the thermal conductivity is attributed to the reduction of the phonon mean free path according to the kinetic theory.

  18. Toxicogenomic effect of nickel and beyond

    OpenAIRE

    Yao, Yixin; Costa, Max

    2014-01-01

    Nickel is widely applied in industrial settings and Ni (II) compounds have been classified as group one human carcinogens. The molecular basis of Ni (II) carcinogenicity has proved complex, for many stress response pathways are activated and yield unexpected Ni (II) specific toxicology profile. Ni (II) induced toxicogenomic change has been associated with altered activity of HIF, p53, c-MYC, NFκB and iron and 2-oxoglutarate dependent dioxygenases. Advancing high-throughput technology has indi...

  19. Thin Film Synthesis of Nickel Containing Compounds

    OpenAIRE

    Lindahl, Erik

    2009-01-01

    Most electrical, magnetic or optical devices are today based on several, usually extremely thin layers of different materials.  In this thesis chemical synthesis processes have been developed for growth of less stable and metastable layers, and even multilayers, of nickel containing compounds. A chemical vapor deposition (CVD) method for deposition of metastable Ni3N has been developed.  The deposition process employs ammonia as nitrogen precursor. An atomic layer deposition (ALD) process for...

  20. Surface Bond Strength in Nickel Based Alloys

    OpenAIRE

    Ramesh, Ganesh; Padmanabhan, T. V.; Ariga, Padma; Joshi, Shalini; Bhuminathan, S.; Vijayaraghavan, Vasantha

    2012-01-01

    Bonding of ceramic to the alloy is essential for the longevity of porcelain fused to metal restorations. Imported alloys used now a days in processing them are not economical. So this study was conducted to evaluate and compare the bond strength of ceramic material to nickel based cost effective Nonferrous Materials Technology Development Center (NFTDC), Hyderabad and Heraenium S, Heraeus Kulzer alloy. An Instron testing machine, which has three-point loading system for the application of loa...

  1. Deformation strain inhomogeneity in columnar grain nickel

    DEFF Research Database (Denmark)

    Wu, G.L.; Godfrey, A.; Juul Jensen, D.;

    2005-01-01

    A method is presented for determination of the local deformation strain of individual grains in the bulk of a columnar grain sample. The method, based on measurement of the change in grain area of each grain, is applied to 12% cold rolled nickel. Large variations are observed in the local strain...... associated with each grain. (c) 2005 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved....

  2. Stainless chromium-nickel steels. Chapter I

    International Nuclear Information System (INIS)

    The chemical composition is tabulated of 90 chromium-nickel stainless steels and alloys given in volume %. The values are also given of the corrosion resistance of the steels and alloys. The tables show data on the surface condition or the methods of material working, types and chemical composition of the medium where corrosion resistance tests were carried out, temperature, pressure, time of tests, corrosion rates, corrosion types, and literature references. A total of 35 references is given. (J.B.)

  3. Black Youth Unemployment and the Black Family.

    Science.gov (United States)

    Hoskins, Linus A.

    This paper analyzes the results of a survey conducted to ascertain the attitudes of 400 employers, youth, and academic/community professionals in Los Angeles, Chicago and Washington, D.C., toward an approach to Black youth unemployment centered on the creation of jobs and training among minority businesses in selected metropolitan areas. Minority…

  4. Nickel-free austenitic stainless steels for medical applications

    Directory of Open Access Journals (Sweden)

    Ke Yang and Yibin Ren

    2010-01-01

    Full Text Available The adverse effects of nickel ions being released into the human body have prompted the development of high-nitrogen nickel-free austenitic stainless steels for medical applications. Nitrogen not only replaces nickel for austenitic structure stability but also much improves steel properties. Here we review the harmful effects associated with nickel in medical stainless steels, the advantages of nitrogen in stainless steels, and emphatically, the development of high-nitrogen nickel-free stainless steels for medical applications. By combining the benefits of stable austenitic structure, high strength and good plasticity, better corrosion and wear resistances, and superior biocompatibility compared to the currently used 316L stainless steel, the newly developed high-nitrogen nickel-free stainless steel is a reliable substitute for the conventional medical stainless steels.

  5. Investigation of nickel hydrogen battery technology for the RADARSAT spacecraft

    Science.gov (United States)

    Mccoy, D. A.; Lackner, J. L.

    1986-01-01

    The low Earth orbit (LEO) operations of the RADARSAT spacecraft require high performance batteries to provide energy to the payload and platform during eclipse period. Nickel Hydrogen cells are currently competing with the more traditional Nickel Cadmium cells for high performance spacecraft applications at geostationary Earth orbit (GEO) and Leo. Nickel Hydrogen cells appear better suited for high power applications where high currents and high Depths of Discharge are required. Although a number of GEO missions have flown with Nickel Hydrogen batteries, it is not readily apparent that the LEO version of the Nickel Hydrogen cell is able to withstand the extended cycle lifetime (5 years) of the RADARSAT mission. The problems associated with Nickel Hydrogen cells are discussed in the contex of RADARSAT mission and a test program designed to characterize cell performance is presented.

  6. Production of nickel oxide thin films by magnetron sputtering

    International Nuclear Information System (INIS)

    Discrepancies between short-circuit diffusion data derived from nickel oxide bicrystals and specimens produced by the oxidation of nickel has led to a requirement for thin film nickel oxide specimens of controlled microstructure and impurity level that can be produced independently of the oxidation process. RF magnetron sputtering of nickel oxide has been used to produce thin films intended for this application. The as-deposited films contain excess oxygen compared to stoichiometric nickel oxide and exhibit strong preferred orientation. Annealing in argon leads to oxygen deficient films. The reduction in porosity which accompanies the annealing leads to the formation of through-thickness cracks in the films. Subsequent oxygen tracer studies demonstrate that the cracks give rise to excessive oxygen transport through the films compared to that expected for thermally oxidised scales. The microstructural anomalies produced by the annealing process mean that the required microstructures were not achieved and these films are not useful analogues of thermal nickel oxide scales. (author)

  7. Preparation and Characterization of Monodisperse Nickel Nanoparticles by Polyol Process

    Institute of Scientific and Technical Information of China (English)

    LI Peng; GUAN Jianguo; ZHANG Qingjie; ZHAO Wenyu

    2005-01-01

    Polymer-protected monodisperse nickel nanoparticles were synthesized by a modified polyol reduction method in the presence of poly ( N-vinyl- 2-pyrrolidone ). These nanoparticles were characterized by transmission electron microscopy (TEM), X- ray diffraction ( XRD ), selected area electron diffraction ( SAED ), as well as vibrating sample magnetometer (VSM). The experimental results show that the addition of PVP and the concentration of NaOH have strong influences on the size, agglomeration and uniformity of nanoparticles. In the presence of PVP and NaOH with low concentrations, monodisperse nickel nanoparticles with average diameters about 42 nm were obtained and characterized to be pure nickel crystalline with fcc structure. Secondary structures such as clusters, loops, and strings resulted from magnetic interactions between particles were observed. The chemical interaction between the PVP and nickel nanoparticles was found by FTIR. The saturation magnetization ( Ms ), remanent magnetization (Mr) and coercivity ( Hc ) of these nickel nanoparticles are lower than those of bulk nickel.

  8. Enhancement of anaerobic hydrogen production by iron and nickel

    Energy Technology Data Exchange (ETDEWEB)

    Karadag, Dogan; Puhakka, Jaakko A. [Department of Chemistry and Bioengineering, Tampere University of Technology, Tampere (Finland)

    2010-08-15

    The effects of iron and nickel on hydrogen (H{sub 2}) production were investigated in a glucose-fed anaerobic Continuous Flow Stirred Tank Reactor (ACSTR). Both iron and nickel improved the reactor performance and H{sub 2} production was enhanced by 71% with the sole iron or nickel supplementation. In all cases, H{sub 2} production yield was increased by lowering both ethanol and total metabolites production and increasing butyrate production. Furthermore, iron and nickel slightly increased biomass production while glucose degradation decreased with the supplementation of nickel. Dynamic changes in bacterial composition as analyzed by 16S rRNA gene-targeted denaturing gradient gel electrophoresis (DGGE) revealed that hydrogen was produced mainly by Clostridium butyricum strains and that nickel addition decreased the microbial diversity. (author)

  9. Electrospinning of Ceria and Nickel Oxide Nanofibers

    Science.gov (United States)

    Yerasi, Jyothi Swaroop Reddy

    Electrospinning uses an electrical charge to draw very fine fibers from a liquid. It has very high potential for industrial processing. Electrospinning is cost effective, repeatable and it can produce long, continuous nanofibers. Polymers such as polyalcohol, polyamides, and PLLA can be easily electrospun. The increase in demand for clean energy combined with the research work in progress and the potential advantages of electrospun electrodes over conventionally fabricated SOFCs makes electrospinning a strong candidate. In this thesis, ceramic nanofibers (ceria and nickel oxide) that can potentially be used in SOFCs are fabricated. A three-phase approach is implemented in the fabrication of ceria and nickel oxide nanofibers. The first phase involves the preparation of the composite ceramic-polymer solution to be electrospun. The second phase gives the processing conditions such as voltage applied, feed rate, and gauge of syringe tip used for successfully electrospinning composite ceramic-polymer fibers. The final stage demonstrates the temperature cycles used to burn out the polymer and calcine the ceramic particles in the ceramic-polymer nanofibers leaving behind ceria and nickel oxide nanofibers. Techniques such as scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray Diffraction (XRD) were used to measure the average diameter of the fibers formed and to understand the chemical composition and crystallanity of the nanofibers after calcination. This thesis also discusses the advantages and possibility of fabricating side-by-side nanofibers and oriented nanofiber mats.

  10. The Black Family in American Economy: Black Capitalism.

    Science.gov (United States)

    Ezeocha, Peter A.

    Black capitalism that is well planned and run is a source of enumerable benefits to the American society in general and to blacks in particular. It generates opportunities for blacks to perform in occupations which for many years were closed to them. For hundreds of years blacks have been despised and often looked down upon on account of the fact…

  11. On the Charter Question: Black Marxism and Black Nationalism

    Science.gov (United States)

    Stern, Mark; Hussain, Khuram

    2015-01-01

    This article brings two black intellectual traditions to bear on the question of charter schools: black Marxism and black nationalism. The authors examine the theoretical and rhetorical devices used to talk about charters schools by focusing on how notions of "black liberation" are deployed by the charter movement, and to what end. The…

  12. Rapid nickel oxalate thermal decomposition for producing fine nickel metal powders

    Energy Technology Data Exchange (ETDEWEB)

    Carney, C.S. [University of Colorado, Department of Chemical and Biological Engineering, UCB 424, Boulder, CO 80309-0424 (United States); Gump, C.J. [University of Colorado, Department of Chemical and Biological Engineering, UCB 424, Boulder, CO 80309-0424 (United States); Hrenya, C.M. [University of Colorado, Department of Chemical and Biological Engineering, UCB 424, Boulder, CO 80309-0424 (United States); Weimer, A.W. [University of Colorado, Department of Chemical and Biological Engineering, UCB 424, Boulder, CO 80309-0424 (United States)]. E-mail: alan.weimer@colorado.edu

    2006-09-15

    The global kinetics for the thermal decomposition of nickel oxalate within an aerosol flow reactor are studied by developing a one-dimensional particle phase model that describes the particle behavior within the reactor. The solid precursor is nickel oxalate with an average particle size of 12 {mu}m. The particles are large enough in size for the gravitational force to cause slip between the particle and fluid phases, thus the particles pass through the reactor slightly faster than the gas phase. The particle residence times for the kinetic study range from 2-6 s for reactor temperatures of 695-767 K. First-order kinetics best fit the experimental conversion data. The decomposition reaction is interpreted as instantaneous nucleation of nano-sized product nickel, followed by two-dimensional growth of these nuclei, controlled by diffusion of product carbon dioxide.

  13. Rapid nickel oxalate thermal decomposition for producing fine nickel metal powders

    International Nuclear Information System (INIS)

    The global kinetics for the thermal decomposition of nickel oxalate within an aerosol flow reactor are studied by developing a one-dimensional particle phase model that describes the particle behavior within the reactor. The solid precursor is nickel oxalate with an average particle size of 12 μm. The particles are large enough in size for the gravitational force to cause slip between the particle and fluid phases, thus the particles pass through the reactor slightly faster than the gas phase. The particle residence times for the kinetic study range from 2-6 s for reactor temperatures of 695-767 K. First-order kinetics best fit the experimental conversion data. The decomposition reaction is interpreted as instantaneous nucleation of nano-sized product nickel, followed by two-dimensional growth of these nuclei, controlled by diffusion of product carbon dioxide

  14. Structural, optical and electrochromic properties of nickel oxide thin films grown from electrodeposited nickel sulphide

    International Nuclear Information System (INIS)

    Nickel oxide thin films were grown onto FTO-coated glass substrates by a two-step process: electrodeposition of nickel sulphide and their thermal oxidation at 425, 475 and 525 deg. C. The influence of thermal oxidation temperature on structural, optical, morphological and electrochromic properties was studied. The structural properties undoubtedly revealed NiO formation. The electrochromic properties were studied by means of cyclic voltammetry. The films exhibited anodic electrochromism, changing from a transparent state to a coloured state at +0.75 V versus SCE, i.e. by simultaneous ion and electron ejection. The transmittance in the coloured and bleached states was recorded to access electrochromic quality of the films. Colouration efficiency and electrochromic reversibility were found to be maximum (21 mC/cm2 and 89%, respectively) for the films oxidized at 425 deg. C. The optical band gap energy of nickel oxide slightly varies with increase in annealing temperature

  15. Structural, optical and electrochromic properties of nickel oxide thin films grown from electrodeposited nickel sulphide

    Energy Technology Data Exchange (ETDEWEB)

    Uplane, M.M.; Mujawar, S.H.; Inamdar, A.I.; Shinde, P.S.; Sonavane, A.C. [Thin Film Materials Laboratory, Department of Physics, Shivaji University, Kolhapur 416004, Maharashtra (India); Patil, P.S. [Thin Film Materials Laboratory, Department of Physics, Shivaji University, Kolhapur 416004, Maharashtra (India)], E-mail: psp_phy@unishivaji.ac.in

    2007-10-15

    Nickel oxide thin films were grown onto FTO-coated glass substrates by a two-step process: electrodeposition of nickel sulphide and their thermal oxidation at 425, 475 and 525 deg. C. The influence of thermal oxidation temperature on structural, optical, morphological and electrochromic properties was studied. The structural properties undoubtedly revealed NiO formation. The electrochromic properties were studied by means of cyclic voltammetry. The films exhibited anodic electrochromism, changing from a transparent state to a coloured state at +0.75 V versus SCE, i.e. by simultaneous ion and electron ejection. The transmittance in the coloured and bleached states was recorded to access electrochromic quality of the films. Colouration efficiency and electrochromic reversibility were found to be maximum (21 mC/cm{sup 2} and 89%, respectively) for the films oxidized at 425 deg. C. The optical band gap energy of nickel oxide slightly varies with increase in annealing temperature.

  16. Structural, optical and electrochromic properties of nickel oxide thin films grown from electrodeposited nickel sulphide

    Science.gov (United States)

    Uplane, M. M.; Mujawar, S. H.; Inamdar, A. I.; Shinde, P. S.; Sonavane, A. C.; Patil, P. S.

    2007-10-01

    Nickel oxide thin films were grown onto FTO-coated glass substrates by a two-step process: electrodeposition of nickel sulphide and their thermal oxidation at 425, 475 and 525 °C. The influence of thermal oxidation temperature on structural, optical, morphological and electrochromic properties was studied. The structural properties undoubtedly revealed NiO formation. The electrochromic properties were studied by means of cyclic voltammetry. The films exhibited anodic electrochromism, changing from a transparent state to a coloured state at +0.75 V versus SCE, i.e. by simultaneous ion and electron ejection. The transmittance in the coloured and bleached states was recorded to access electrochromic quality of the films. Colouration efficiency and electrochromic reversibility were found to be maximum (21 mC/cm 2 and 89%, respectively) for the films oxidized at 425 °C. The optical band gap energy of nickel oxide slightly varies with increase in annealing temperature.

  17. Structural, dielectric and magnetic properties of nickel substituted cobalt ferrite nanoparticles: Effect of nickel concentration

    International Nuclear Information System (INIS)

    Nickel substituted cobalt ferrite nanoparticles with composition Co1−xNixFe2O4 (0.0 ≤ x ≤ 1.0) was synthesized using simple, low temperature auto combustion method. The X-ray diffraction patterns reveal the formation of cubic phase spinel structure. The crystallite size varies from 30-44 nm with the nickel content. Porous and agglomerated morphology of the bulk sample was displayed in the scanning electron microscopy. Micro Raman spectroscopy reveals continuous shift of Eg and Eg(2) stokes line up to 0.8 Ni substitution. The dispersion behavior of the dielectric constant with frequency and the semicircle nature of the impedance spectra show the cobalt nickel ferrite to have high resistance. The ferromagnetic nature is observed in all the samples, however, the maximum saturation magnetization was achieved by the 0.4 Ni substituted cobalt ferrite, which is up to the 92.87 emu/gm at 30K

  18. Nickel catalysts for internal reforming in molten carbonate fuel cells

    OpenAIRE

    Berger, R.J.; Doesburg, E.B.M.; Ommen, van, B.; Ross, J.R.H.

    1996-01-01

    Natural gas may be used instead of hydrogen as fuel for the molten carbonate fuel cell (MCFC) by steam reforming the natural gas inside the MCFC, using a nickel catalyst (internal reforming). The severe conditions inside the MCFC, however, require that the catalyst has a very high stability. In order to find suitable types of nickel catalysts and to obtain more knowledge about the deactivation mechanism(s) occurring during internal reforming, a series of nickel catalysts was prepared and subj...

  19. Nickel N-heterocyclic carbene complexes in homogeneous catalysis

    OpenAIRE

    Berding, Joris

    2009-01-01

    Described in this thesis are the investigations into the chemistry of N-heterocyclic carbene (NHC) ligands and transition-metal complexes thereof. Specifically, a variety of N-heterocyclic carbene complexes of nickel were prepared, characterized and used as catalysts in three types of homogeneous catalytic processes. First, nickel(II) complexes of monodentate NHC ligands were successfully used as catalysts in the hydrosilylation of internal alkynes. Second, nickel(II) complexes bearing bident...

  20. Investigation and growth of nickel coatings for electrical contact applications

    OpenAIRE

    Fawakhiri, Maria

    2009-01-01

    Nickel based coatings were deposited on copper substrates by two different sputtering techniques from a nickel alloy based target. The substrates used were commercially available copper based substrates for low duty electrical contacts. The coatings were analyzed and evaluated as copper diffusion barriers for electrical contact applications. In addition two types of commercially available electroplated nickel coatings (referred to as type A electroplated coatings and type B electroplated coat...

  1. Influence of nickel speciation on electrokinetic sediment remediation efficiency

    OpenAIRE

    Rajić Ljiljana; Dalmacija Božo; Ugarčina-Perović Svetlana; Watson Malcolm; Dalmacija Milena

    2011-01-01

    This article presents a bench-scale investigation of nickel removal during electrokinetic (EK) remediation of sediment, and the dependency of removal efficacies upon the speciation of the metal, as influenced by the duration of the nickel-sediment interaction. The sediment used in this study was from the Grand Backa canal (Vojvodina, Republic of Serbia). The sediment used is anaerobic and the nickel pollution has been aged for several years, so it is mostly sorbed by sulphides and organ...

  2. Nickel/ruthenium catalyst and method for aqueous phase reactions

    Science.gov (United States)

    Elliott, Douglas C.; Sealock, John L.

    1998-01-01

    A method of hydrogenation using a catalyst in the form of a plurality of porous particles wherein each particle is a support having nickel metal catalytic phase or reduced nickel deposited thereon in a first dispersed phase and an additional ruthenium metal deposited onto the support in a second dispersed phase. The additional ruthenium metal is effective in retarding or reducing agglomeration or sintering of the nickel metal catalytic phase thereby increasing the life time of the catalyst during hydrogenation reactions.

  3. Synthesis of hybrid nickel nanocrystals/polystyrene coloidal particles

    International Nuclear Information System (INIS)

    This present work shows a method to produce and encapsulate magnetic nickel nanocrystals into polymeric colloidal particles. The nickel nanoparticles were produced by a thermal decomposition method, the particles formed were approximately 10 nm in size and quite monodisperse. The method to encapsulate the nickel nanoparticles was the mini emulsion polymerization. The particles were investigated before and after encapsulation by a transmission electron microscopy and energy dispersive X-ray analyses. (author)

  4. Synthesis of hybrid nickel nanocrystals/polystyrene coloidal particles

    Energy Technology Data Exchange (ETDEWEB)

    Staudt, T.; Vogel, N.; Weiss, C.; Landfester, K. [Max Planck Institute for Polymer Research, Mainz (Germany); Araujo, P.H.H.; Sayer, C., E-mail: csayer@enq.ufsc.b [Federal University of Santa Catarina (UFSC), Florianopolis, SC (Brazil). Dept. of Chemical Engineering

    2009-07-01

    This present work shows a method to produce and encapsulate magnetic nickel nanocrystals into polymeric colloidal particles. The nickel nanoparticles were produced by a thermal decomposition method, the particles formed were approximately 10 nm in size and quite monodisperse. The method to encapsulate the nickel nanoparticles was the mini emulsion polymerization. The particles were investigated before and after encapsulation by a transmission electron microscopy and energy dispersive X-ray analyses. (author)

  5. ULTRAMASSIVE BLACK HOLE COALESCENCE

    International Nuclear Information System (INIS)

    Although supermassive black holes (SMBHs) correlate well with their host galaxies, there is an emerging view that outliers exist. Henize 2-10, NGC 4889, and NGC 1277 are examples of SMBHs at least an order of magnitude more massive than their host galaxy suggests. The dynamical effects of such ultramassive central black holes is unclear. Here, we perform direct N-body simulations of mergers of galactic nuclei where one black hole is ultramassive to study the evolution of the remnant and the black hole dynamics in this extreme regime. We find that the merger remnant is axisymmetric near the center, while near the large SMBH influence radius, the galaxy is triaxial. The SMBH separation shrinks rapidly due to dynamical friction, and quickly forms a binary black hole; if we scale our model to the most massive estimate for the NGC 1277 black hole, for example, the timescale for the SMBH separation to shrink from nearly a kiloparsec to less than a parsec is roughly 10 Myr. By the time the SMBHs form a hard binary, gravitational wave emission dominates, and the black holes coalesce in a mere few Myr. Curiously, these extremely massive binaries appear to nearly bypass the three-body scattering evolutionary phase. Our study suggests that in this extreme case, SMBH coalescence is governed by dynamical friction followed nearly directly by gravitational wave emission, resulting in a rapid and efficient SMBH coalescence timescale. We discuss the implications for gravitational wave event rates and hypervelocity star production

  6. Nickel-Based Superalloy Resists Embrittlement by Hydrogen

    Science.gov (United States)

    Lee, Jonathan; Chen, PoShou

    2008-01-01

    A nickel-based superalloy that resists embrittlement by hydrogen more strongly than does nickel alloy 718 has been developed. Nickel alloy 718 is the most widely used superalloy. It has excellent strength and resistance to corrosion as well as acceptably high ductility, and is recognized as the best alloy for many high-temperature applications. However, nickel alloy 718 is susceptible to embrittlement by hydrogen and to delayed failure and reduced tensile properties in gaseous hydrogen. The greater resistance of the present nickel-based superalloy to adverse effects of hydrogen makes this alloy a superior alternative to nickel alloy 718 for applications that involve production, transfer, and storage of hydrogen, thereby potentially contributing to the commercial viability of hydrogen as a clean-burning fuel. The table shows the composition of the present improved nickel-based superalloy in comparison with that of nickel alloy 718. This composition was chosen to obtain high resistance to embrittlement by hydrogen while maintaining high strength and exceptional resistance to oxidation and corrosion. The most novel property of this alloy is that it resists embrittlement by hydrogen while retaining tensile strength greater than 175 kpsi (greater than 1.2 GPa). This alloy exhibits a tensile elongation of more than 20 percent in hydrogen at a pressure of 5 kpsi (approximately equal to 34 MPa) without loss of ductility. This amount of elongation corresponds to 50 percent more ductility than that exhibited by nickel alloy 718 under the same test conditions.

  7. Control of the morphology and surface properties of nickel ferrite

    International Nuclear Information System (INIS)

    Nickel ferrite powders with particle sizes in the 3-5 μm range have been prepared from coprecipitated nickel-iron oxalate precursors. Firing the nickel-iron oxalate precursor in the range 300-1100oC produced samples of high chemical purity, while introducing significant variations in the distribution of crystallite sizes and surface morphologies. An increase in the powder density from 4.2 to 5.2 g cm-3 and a decrease in the surface area of the nickel ferrite from 120 to 0.2 m2 g-1 were effected by increasing the firing temperature to 1100oC. (author)

  8. Noncommutative Solitonic Black Hole

    CERN Document Server

    Chang-Young, Ee; Lee, Daeho; Lee, Youngone

    2012-01-01

    We investigate solitonic black hole solutions in three dimensional noncommutative spacetime. We do this in gravity with negative cosmological constant coupled to a scalar field using the Moyal product expanded up to first order in the noncommutativity parameter in the two noncommutative spatial directions. By numerical simulation we look for black hole solutions by increasing the non- commutativity parameter value starting from regular solutions with vanishing noncommutativity. We find that even a regular soliton solution in the commutative case becomes a black hole solution when the noncommutativity parameter reaches a certain value.

  9. Black holes new horizons

    CERN Document Server

    Hayward, Sean Alan

    2013-01-01

    Black holes, once just fascinating theoretical predictions of how gravity warps space-time according to Einstein's theory, are now generally accepted as astrophysical realities, formed by post-supernova collapse, or as supermassive black holes mysteriously found at the cores of most galaxies, powering active galactic nuclei, the most powerful objects in the universe. Theoretical understanding has progressed in recent decades with a wider realization that local concepts should characterize black holes, rather than the global concepts found in textbooks. In particular, notions such as trapping h

  10. Reflection from black holes

    CERN Document Server

    Kuchiev, M Yu

    2003-01-01

    Black holes are presumed to have an ideal ability to absorb and keep matter. Whatever comes close to the event horizon, a boundary separating the inside region of a black hole from the outside world, inevitably goes in and remains inside forever. This work shows, however, that quantum corrections make possible a surprising process, reflection: a particle can bounce back from the event horizon. For low energy particles this process is efficient, black holes behave not as holes, but as mirrors, which changes our perception of their physical nature. Possible ways for observations of the reflection and its relation to the Hawking radiation process are outlined.

  11. Scalarized hairy black holes

    International Nuclear Information System (INIS)

    In the presence of a complex scalar field scalar–tensor theory allows for scalarized rotating hairy black holes. We exhibit the domain of existence for these scalarized black holes, which is bounded by scalarized rotating boson stars and hairy black holes of General Relativity. We discuss the global properties of these solutions. Like their counterparts in general relativity, their angular momentum may exceed the Kerr bound, and their ergosurfaces may consist of a sphere and a ring, i.e., form an ergo-Saturn

  12. Scalarized hairy black holes

    Energy Technology Data Exchange (ETDEWEB)

    Kleihaus, Burkhard, E-mail: b.kleihaus@uni-oldenburg.de [Institut für Physik, Universität Oldenburg, Postfach 2503, D-26111 Oldenburg (Germany); Kunz, Jutta [Institut für Physik, Universität Oldenburg, Postfach 2503, D-26111 Oldenburg (Germany); Yazadjiev, Stoytcho [Department of Theoretical Physics, Faculty of Physics, Sofia University, Sofia 1164 (Bulgaria)

    2015-05-11

    In the presence of a complex scalar field scalar–tensor theory allows for scalarized rotating hairy black holes. We exhibit the domain of existence for these scalarized black holes, which is bounded by scalarized rotating boson stars and hairy black holes of General Relativity. We discuss the global properties of these solutions. Like their counterparts in general relativity, their angular momentum may exceed the Kerr bound, and their ergosurfaces may consist of a sphere and a ring, i.e., form an ergo-Saturn.

  13. Scalarized Hairy Black Holes

    CERN Document Server

    Kleihaus, Burkhard; Yazadjiev, Stoytcho

    2015-01-01

    In the presence of a complex scalar field scalar-tensor theory allows for scalarized rotating hairy black holes. We exhibit the domain of existence for these scalarized black holes, which is bounded by scalarized rotating boson stars and ordinary hairy black holes. We discuss the global properties of these solutions. Like their counterparts in general relativity, their angular momentum may exceed the Kerr bound, and their ergosurfaces may consist of a sphere and a ring, i.e., form an ergo-Saturn.

  14. Toxicity of nickel-spiked freshwater sediments to benthic invertebrates-Spiking methodology, species sensitivity, and nickel bioavailability

    Science.gov (United States)

    Besser, John M.; Brumbaugh, William G.; Kemble, Nile E.; Ivey, Chris D.; Kunz, James L.; Ingersoll, Christopher G.; Rudel, David

    2011-01-01

    This report summarizes data from studies of the toxicity and bioavailability of nickel in nickel-spiked freshwater sediments. The goal of these studies was to generate toxicity and chemistry data to support development of broadly applicable sediment quality guidelines for nickel. The studies were conducted as three tasks, which are presented here as three chapters: Task 1, Development of methods for preparation and toxicity testing of nickel-spiked freshwater sediments; Task 2, Sensitivity of benthic invertebrates to toxicity of nickel-spiked freshwater sediments; and Task 3, Effect of sediment characteristics on nickel bioavailability. Appendices with additional methodological details and raw chemistry and toxicity data for the three tasks are available online at http://pubs.usgs.gov/sir/2011/5225/downloads/.

  15. Combination nickel foam expanded nickel screen electrical connection supports for solid oxide fuel cells

    Science.gov (United States)

    Draper, Robert; Prevish, Thomas; Bronson, Angela; George, Raymond A.

    2007-01-02

    A solid oxide fuel assembly is made, wherein rows (14, 25) of fuel cells (17, 19, 21, 27, 29, 31), each having an outer interconnection (20) and an outer electrode (32), are disposed next to each other with corrugated, electrically conducting expanded metal mesh member (22) between each row of cells, the corrugated mesh (22) having top crown portions and bottom portions, where the top crown portion (40) have a top bonded open cell nickel foam (51) which contacts outer interconnections (20) of the fuel cells, said mesh and nickel foam electrically connecting each row of fuel cells, and where there are no more metal felt connections between any fuel cells.

  16. Thermal and mechanical treatments for nickel and some nickel-base alloys: Effects on mechanical properties

    Science.gov (United States)

    Hall, A. M.; Beuhring, V. F.

    1972-01-01

    This report deals with heat treating and working nickel and nickel-base alloys, and with the effects of these operations on the mechanical properties of the materials. The subjects covered are annealing, solution treating, stress relieving, stress equalizing, age hardening, hot working, cold working, combinations of working and heat treating (often referred to as thermomechanical treating), and properties of the materials at various temperatures. The equipment and procedures used in working the materials are discussed, along with the common problems that may be encountered and the precautions and corrective measures that are available.

  17. EXAFS measurements of nickel/nickel oxide nanoparticles and its comparison with TEM and XRD results

    International Nuclear Information System (INIS)

    Full text: We have synthesized the nickel nanoparticles by pulsed laser ablation. The nickel disc in sodium dodecyl sulfate (SDS) with surfactant concentration of 10 mM and 20 mM, was used with the focused output of fundamental harmonic from Nd:YAG laser operating at the first harmonic (Iambda= 1064 nm). The laser power was fixed at 35 mJ/pulse with 10 ns pulse width and 10Hz repetition rate and was used for the ablation for 60 minute. Nickel oxide nanoparticles were synthesized by chemical method for different concentration of surfactant Cetyltrimethylammonium bromide (ClAB). the surfactant was used to provide favourable site for the growth of the particulate assemblies, which influences the formation process, including nucleation, growth, coagulation and flocculation. the materials used for synthesis were nickel chloride hexahydrate, sodium hydroxide (NaOH) and Cetyltrimethylammonium bromide (ClAB). UV-Visible absorption, X-ray diffraction, and transmission Electron Microscopy techniques were used for the characterization of produced nanoparticles. The powder samples were characterized by XRD measurements using Cu-Kα radiation at 40 KV with wavelength 1.5405 A0. The EXAFS studies of pure nickel foil and for the synthesized nanoparticles with concentration 10mM of SDS show similar structures. The position of the main peak is same. The only difference was observed in the reduction of the amplitude, which can be attributed to the coordination number. The nearest neighbor distance was similar as for pure nickel foil. The Debye-Waller factor was also similar on comparison. There was no trace of oxide and hydroxide in the EXAFS data which suggest that the synthesized nanoparticles contain only nickel metal. The extended X-ray absorption fine structure (EXAFS) studies of calculated FEFF of nickel oxide and the synthesized nanoparticles with different concentration of ClAB show similar structures. In comparison to standard NiO spectra the reduction of the amplitude and

  18. On Noncommutative Black Holes Thermodynamics

    CERN Document Server

    Faizal, Mir; Ulhoa, S C

    2015-01-01

    In this paper, we will analyze noncommutative deformation of the Schwarzschild black holes and Kerr black holes. We will perform our analysis by relating the commutative and the noncommutative metrics using an Moyal product. We will also analyze the thermodynamics of these noncommutative black hole solutions. We will explicitly derive expression for the corrected entropy and temperature of these black hole solutions.

  19. The Thermodynamics of Black Holes

    Directory of Open Access Journals (Sweden)

    Wald Robert M.

    2001-01-01

    Full Text Available We review the present status of black hole thermodynamics. Our review includes discussion of classical black hole thermodynamics, Hawking radiation from black holes, the generalized second law, and the issue of entropy bounds. A brief survey also is given of approaches to the calculation of black hole entropy. We conclude with a discussion of some unresolved open issues.

  20. The Price of "Black Dominance."

    Science.gov (United States)

    Hoberman, John

    2000-01-01

    Discusses the harmful effects of stereotyping black males as athletes, noting that over-identification with athletes and the world of physical performance limits black children's development by discouraging academic achievement. Examines the negative influence of mass media focus on black athletes, rappers, and stylized ghetto blackness. Discusses…

  1. The Thermodynamics of Black Holes

    OpenAIRE

    Wald Robert M.

    1999-01-01

    We review the present status of black hole thermodynamics. Our review includes discussion of classical black hole thermodynamics, Hawking radiation from black holes, the generalized second law, and the issue of entropy bounds. A brief survey also is given of approaches to the calculation of black hole entropy. We conclude with a discussion of some unresolved open issues.

  2. Black Writers' Views of America.

    Science.gov (United States)

    Ladner, Joyce

    1979-01-01

    Black literature of the 1960s reflected protest and an affirmation of Black power and Black consciousness. The 1970s have produced a counterwave in which Blacks, in order to achieve literary and financial recognition, have begun to focus less on race and social criticism and more on conservative and narcissistic themes. (Author/EB)

  3. Topics in black hole evaporation

    International Nuclear Information System (INIS)

    Two major aspects of particle creation by gravitational fields of black holes are studied: the neutrino emission from rotating black holes; and interactions between scalar particles emitted by a black hole. Neutrino emission is investigated under three topics: The asymmetry of the angular dependence of neutrino emission from rotating black holes; the production of a local matter excess by rotating black holes in a baryon symmetric universe; and cosmological magnetic field generation by neutrinos from evaporating black holes. Finally the author studies the effects of interactions on the black hole evaporation process

  4. Black Holes in Higher Dimensions

    International Nuclear Information System (INIS)

    In four space-time dimensions black holes of Einstein-Maxwell theory satisfy a number of theorems. In more than four space-time dimensions, however, some of the properties of black holes can change. In particular, uniqueness of black holes no longer holds. In five and more dimensions black rings arise. Thus in a certain region of the phase diagram there are three black objects with the same global charges present. Here we discuss properties of higher-dimensional vacuum and charged black holes, which possess a spherical horizon topology, and of vacuum and charged black rings, which have a ringlike horizon topology

  5. Electroless Co-Zn Surface-modified Nickel Hydroxide as an Active Material for Pasted Nickel Electrodes

    Institute of Scientific and Technical Information of China (English)

    SONG Quan-sheng(宋全生); TANG Zhi-yuan(唐致远); GUO He-tong(郭鹤桐); CHAN S L I

    2004-01-01

    Chemically precipitated β-type nickel hydroxide powder was surface-modified by electroless deposition of Co-Zn coatings,and physical properties of both the modified and unmodified nickel hydroxide were characterized by scanning electron microscopy (SEM), specific surface area (BET), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). It has been found that Co and Zn components of the surface electroless coatings exist in the oxidized state. Electrochemical performances of pasted nickel electrodes using the modified nickel hydroxide as an active material were investigated, and compared with those of the electrodes prepared with the unmodified nickel hydroxide. Charge/discharge tests show that the modified nickel hydroxide electrodes exhibit better performances in the charge efficiency, specific discharge capacity and active material utilization. Their resistance to swelling with cycling is also superior to that of the unmodified nickel hydroxide electrodes. Cyclic voltammetric (CV) studies indicate that the modified electrodes have a higher electrochemical activity, and the porous pasted nickel electrodes have some distinguished CV characteristics in comparison with those of the thin film nickel electrodes.

  6. Results of a technical analysis of the Hubble Space Telescope nickel-cadmium and nickel-hydrogen batteries

    Science.gov (United States)

    Manzo, Michelle A.

    1991-01-01

    The Hubble Space Telescope (HST) Program Office requested the expertise of the NASA Aerospace Flight Battery Systems Steering Committee (NAFBSSC) in the conduct of an independent assessment of the HST's battery system to assist in their decision of whether to fly nickel-cadmium or nickel-hydrogen batteries on the telescope. In response, a subcommittee to the NAFBSSC was organized with membership comprised of experts with background in the nickel-cadmium/nickel-hydrogen secondary battery/power systems areas. The work and recommendations of that subcommittee are presented.

  7. Introducing the Black Hole

    Science.gov (United States)

    Ruffini, Remo; Wheeler, John A.

    1971-01-01

    discusses the cosmology theory of a black hole, a region where an object loses its identity, but mass, charge, and momentum are conserved. Include are three possible formation processes, theorized properties, and three way they might eventually be detected. (DS)

  8. Black Widow Spider

    Science.gov (United States)

    ... dling boxes, firewood, lumber, and rocks, etc. The black widow is commonly found in the following places: • Outdoors - woodpiles, rubble piles, under stones, in hol- low stumps, and in rodent burrows, privies, sheds ...

  9. Black Sea aerosols

    International Nuclear Information System (INIS)

    Shipboard, high volume air particulate samples were collected from the Black Sea atmosphere and analyzed by instrumental neutron activation analysis, atomic absorption spectrophotometry and ion chromatography for about 40 elements and ions. Concentrations of elements in the eastern and western parts of the Black Sea are different at the 95% confidence level, with lower concentrations in the eastern Black Sea. Back-trajectories and concentrations of elements in trajectory groups show that Europe accounts for more than 70% of the anthropogenic elements in the atmosphere. The average sulfate concentration was 7 μg/m3, which is comparable with rural sulfate levels in western Europe. Fluxes of elements from the atmosphere to the Black Sea are in good agreement with the results of similar flux calculations for other regions

  10. Black Friday = Broget Branding?

    DEFF Research Database (Denmark)

    Hansen, Heidi

    2015-01-01

    Black Friday er et godt eksempel på, hvordan ikke kun produktbrands og corporate brands rejser på tværs af landegrænser, men også traditioner som Halloween, Valentines Day og i dette tilfælde den ultimative tilbuds-fredag, som i USA går under navnet Black Friday. Men hvad er Black Friday i Danmark......? Essensen ved Black Friday er lave priser, og det er der ved første øjekast ikke mange brandingmuligheder forbundet ved, hvis man forstår branding som en måde at skabe ekstra værdi omkring sit produkt eller sin virksomhed. Som brand bliver man dog alligevel nødt til at forholde sig til konceptet, da det er...

  11. Black holes in astrophysics

    International Nuclear Information System (INIS)

    In this review we shall concentrate on the application of the concept of black hole to different areas in astrophysics. Models in which this idea is involved are connected with basically two areas in astrophysics: a) The death of massive stars due to gravitational collapse. This process would lead to the formation of black holes with stellar masses (10-20 M sun). The detection of these kind of - objects is in principle possible, by means of studying the so-called X-ray binary system. b) Active nuclei of galaxies, including quasars as an extreme case. In this case, the best model available to explain the generation of the enormous amounts of energy observed as well as several other properties, is accretion into a supermassive black hole (106-1010 M sun) in the center. The problem of the origin of such black holes is related to cosmology. (author)

  12. Cosmic censorship inside black holes

    CERN Document Server

    Thorlacius, L

    2006-01-01

    A simple argument is given that a traversable Cauchy horizon inside a black hole is incompatible with unitary black hole evolution. The argument assumes the validity of black hole complementarity and applies to a generic black hole carrying angular momentum and/or charge. In the second part of the paper we review recent work on the semiclassical geometry of two-dimensional charged black holes.

  13. Quantum Black Holes as Atoms

    OpenAIRE

    Bekenstein, Jacob D.

    1997-01-01

    In some respects the black hole plays the same role in gravitation that the atom played in the nascent quantum mechanics. This analogy suggests that black hole mass $M$ might have a discrete spectrum. I review the physical arguments for the expectation that black hole horizon area eigenvalues are uniformly spaced, or equivalently, that the spacing between stationary black hole mass levels behaves like 1/M. This sort of spectrum has also emerged in a variety of formal approaches to black hole ...

  14. Cosmological Black Holes

    OpenAIRE

    Stornaiolo, Cosimo

    2001-01-01

    In this paper we propose a model for the formation of the cosmological voids. We show that cosmological voids can form directly after the collapse of extremely large wavelength perturbations into low-density black holes or cosmological black holes (CBH). Consequently the voids are formed by the comoving expansion of the matter that surrounds the collapsed perturbation. It follows that the universe evolves, in first approximation, according to the Einstein-Straus cosmological model. We discuss...

  15. Quantum black holes

    International Nuclear Information System (INIS)

    No particle theory can be complete without gravity. Einstein's theory of gravity is of the Euler-Lagrange form, but standard quantization procedure fails. In quantum gravity the higher order interactions have a dimensionality different form the fundamental ones, because Newton's constant G has dimensions and the renormalization procedure fails. Another problem with quantum gravity is even more mysterious. Suppose that we had regularized the gravitational forces at the small distance end in the way that the weak intermediate vector boson regularized the fundamental 4-fermion interaction vertex of the weak interactions. Then what we discover is that the gravitational forces are unstable. Given sufficiently large amount of matter, it can collapse under its own weight. Classical general relativity tells us what will happen: a black hole is formed. But how is this formulated in quantum theory. S. Hawking observed that when a field theory is quantized in the background metric of a black hole, the black hole actually emits particles in a completely random thermal way. Apparently black holes are just another form of matter unstable against Hawking decay. Unfortunately this picture cannot be complete. The problem is that the quantum version of black holes has infinite phase space, and other symptoms of a run-away solution. Black holes are the heaviest and most compact forms of matter that can be imagined. A complete particle theory can have nothing but a spectrum of black-hole like objects at it high-energy end. This is why it is believed that a resolution of the black hole problem will in time disclose the complete small-distance structure of our world. 6 references

  16. Thermal corpuscular black holes

    OpenAIRE

    Casadio, Roberto; Giugno, Andrea; Orlandi, Alessio

    2015-01-01

    We study the corpuscular model of an evaporating black hole consisting of a specific quantum state for a large number $N$ of self-confined bosons. The single-particle spectrum contains a discrete ground state of energy $m$ (corresponding to toy gravitons forming the black hole), and a gapless continuous spectrum (to accommodate for the Hawking radiation with energy $\\omega>m$). Each constituent is in a superposition of the ground state and a Planckian distribution at the expected Hawking temp...

  17. Black hairy tongue syndrome

    OpenAIRE

    Gurvits, Grigoriy E; Tan, Amy

    2014-01-01

    Black hairy tongue (BHT) is a benign medical condition characterized by elongated filiform lingual papillae with typical carpet-like appearance of the dorsum of the tongue. Its prevalence varies geographically, typically ranging from 0.6% to 11.3%. Known predisposing factors include smoking, excessive coffee/black tea consumption, poor oral hygiene, trigeminal neuralgia, general debilitation, xerostomia, and medication use. Clinical presentation varies but is typically asymptomatic, although ...

  18. Charged Galileon black holes

    Science.gov (United States)

    Babichev, Eugeny; Charmousis, Christos; Hassaine, Mokhtar

    2015-05-01

    We consider an Abelian gauge field coupled to a particular truncation of Horndeski theory. The Galileon field has translation symmetry and couples non minimally both to the metric and the gauge field. When the gauge-scalar coupling is zero the gauge field reduces to a standard Maxwell field. By taking into account the symmetries of the action, we construct charged black hole solutions. Allowing the scalar field to softly break symmetries of spacetime we construct black holes where the scalar field is regular on the black hole event horizon. Some of these solutions can be interpreted as the equivalent of Reissner-Nordstrom black holes of scalar tensor theories with a non trivial scalar field. A self tuning black hole solution found previously is extended to the presence of dyonic charge without affecting whatsoever the self tuning of a large positive cosmological constant. Finally, for a general shift invariant scalar tensor theory we demonstrate that the scalar field Ansatz and method we employ are mathematically compatible with the field equations. This opens up the possibility for novel searches of hairy black holes in a far more general setting of Horndeski theory.

  19. Black hole critical phenomena without black holes

    Indian Academy of Sciences (India)

    Steven L Liebling

    2000-10-01

    Studying the threshold of black hole formation via numerical evolution has led to the discovery of fascinating nonlinear phenomena. Power-law mass scaling, aspects of universality, and self-similarity have now been found for a large variety of models. However, questions remain. Here I briefly review critical phenomena, discuss some recent results, and describe a model which demonstrates similar phenomena without gravity.

  20. TiB2 coating formed on nickel substrates by electroplating in molten salt of fluoride

    Institute of Scientific and Technical Information of China (English)

    LONG Jin-ming; GUO Zhong-cheng; HAN Xia-yun

    2004-01-01

    The TiB2 coatings deposited over nickel substrate by electroplating was investigated, which is in molten salt of a fluoride mixture involving KF, NaF, K2 TiF6 and KBF4. Effects of temperature, cathodic current density (Jc) and duration on the coating's formation were examined. The composition, morphology and structure of the coatings were characterized by scanning electron microscopy (SEM), energy dispersive X-ray detector (EDS) and X-ray diffraction (XRD). The results show that the coatings, with black, smooth and uniform appearance, are composed of predominating TiB2 and small amounts of nickel titanium oxide (Ni0.75 Ti0.125 O). The coatings show a nodular morphology and the grain size is dependent on the Jc and ranges about 1 - 10 μm. There is a linear relationship between the coating's thickness and the time of electrolysis within certain duration range. The reduction of the potassium can take place simultaneously with the electrochemical synthesis of TiB2 as the Jc is in excess of certain level. The hardness of the TiB2 coatings is likely to be deteriorated due to the presence of potassium and Ni0.75Ti0.125 O in the coatings.

  1. Occupational exposure to nickel, uranium and thorium in a nickel mine

    International Nuclear Information System (INIS)

    The workers involved in mining and milling ores are exposed in the workplace to many hazardous agents that can cause a health detriment. In this work, the measurements obtained in a nickel mineral processing facility in the Brazilian Central-West are presented. One of the most important hazardous agents in this facility is the aerosol present in the air that contains nickel, uranium and thorium. The aerosol is inhaled or ingested, metabolised and deposited in the whole body or in specific organs. The surveillance of internal contamination of workers was performed by analysis of urine, fecal and hair samples. The ICP-MS (Inductively Coupled Plasma-Mass Spectrometry) method was used to analytically determine nickel, uranium and thorium in these biological samples. Additional data were obtained by the collection of air samples in the workplace. A cascade impactor with six stages was used to collect mineral dust particles with an aerodynamic diameter in the range of 0.64 to 19.4 μm. The particles impacted in each stage of the cascade impactor were analysed by PIXE (Particle Induced X ray Emission), which permits the determination of elemental mass air concentration and the MMAD (Mass Median Aerodynamic Diameter). The concentrations of nickel, uranium and thorium were determined in the aerosol samples. All the results were analysed using statistical methods and biokinetical modelling was applied to evaluate the internal contamination and to make a risk estimation. (author)

  2. A simple nickel activation process for electroless nickel-phosphorus plating on carbon fiber

    Directory of Open Access Journals (Sweden)

    Tingguo Yan

    2013-02-01

    Full Text Available A new nickel activation process was developed for metalizing the carbon fiber (CF surface with electroless nickel plating. The oxidation and activation processes were examined using X-ray Photoelectron Spectroscopy (XPS, Scanning Electron Microscopy (SEM, Energy Dispersive X-ray Spectrometry (EDS, and X-ray Diffractometry (XRD. XPS analysis showed that HNO3 oxidation improved the O/C ratio of the CF surface, which resulted in an increase in the amount of oxygen-containing groups. As activation time increased, both Nio cluster and Ni-P deposits increased. More than 50 mg of Nio clusters formed on the surface of 1g CF. SEM observations illustrated that particles and island-like shapes were developed from the Nio cluster, which helped to initiate the electroless nickel-plating on the CF surface. A continuous and compact coating with a thickness of about 2 to 3 μm was obtained. EDS results showed that the nickel and phosphorus content in the deposits was 97.34 wt.% and 2.66 wt.%, respectively. XRD indicated that the Ni-P coating was crystalline and the maximum deposition on 1 g CFs was as high as 9000 mg. As the results of the observations reveal, the activation method is a feasible alternative to Pd activation.

  3. Dissolution of Nickel in Copper Residue Generated from Nickel Matte Refining

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The dissolution behavior of nickel during the oxygen-chloride leaching of the copper residue was investigated.Technological variables of the leaching,including oxygen flow rate,concentrations of chloride and sulfuric acid,and temperature,were discussed.

  4. Toxicology and metabolism of nickel compounds. Progress report, December 1, 1975--November 30, 1976. [Tests made with rats and hamsters

    Energy Technology Data Exchange (ETDEWEB)

    Sunderman, F.W. Jr.

    1976-08-15

    The toxicology and metabolism of nickel compounds (NiCl/sub 2/, Ni/sub 3/S/sub 2/, NiS, Ni powder, and Ni(CO)/sub 4/) were investigated in rats and hamsters. Triethylenetetramine (TETA) and d-penicillamine are more effective than other chelating agents (Na-diethyldithiocarbamate, CaNa/sub 2/-versenate, diglycylhistidine-N-methylamide and ..cap alpha..-lipoic acid) as antidotes for acute Ni(II)-toxicity in rats. The antidotal efficacy of triethylenetetramine (TETA) in acute Ni(II)-toxicity is mediated by rapid reduction of the plasma concentration of Ni(II), consistent with renal clearance of the TETA-Ni complex at a rate more than twenty times greater than the renal clearance of non-chelated Ni(II). Fischer rats are more susceptible than other rat strains (Wistar-Lewis, Long-Evans and NIH-Black) to induction of erythrocytosis after an intrarenal injection of Ni/sub 3/S/sub 2/, and elucidation of the serial pathologic changes that occur in rats after an intrarenal injection of Ni/sub 3/S/sub 2/. When amorphous nickel monosulfide (NiS) and nickel subsulfide (Ni/sub 3/S/sub 2/) were administered by im injection to randomly selected Fischer rats in equivalent amounts under identical conditions, NiS did not induce any tumors whereas Ni/sub 3/S/sub 2/ induced sarcomas in almost all of the rats.

  5. Biological effects of nano-nickel in rat lungs after administration by inhalation and by intratracheal instillation

    International Nuclear Information System (INIS)

    We examined the biological effects of the nickel oxide (NiO) nanoparticles by inhalation and instillation study. Wistar male rats were exposed to NiO nanoparticles (nNiOs) for 4 weeks (6 hrs/day). The nNiOs was black-colored NiO (99.8%) and average particle size (APS) was 20 nm. The geometric mean diameter of the particles in the chamber and the daily average exposure concentration were 139 ± 12 nm and 1.0 ± 0.5 x 105 particles/cc, respectively. The deposited amount of nNiOs in the rat lungs at 4 days after the inhalation exposure ended was 29 ± 4 μg. Although nNiOs exposure group showed temporal significant increase in the number of total cells in brochoalveolar lavage fluid (BALF) at 4 days after the exposure end, the difference were not seen at one month after an exposure end compared with control group. The histopathological change was not severe just after the inhalation nor throughout the observation time. Elemental mappings of nickel showed that nickel particles were located in agglomeration at the pulmonary macrophages.

  6. Drinking water pollution with nickel from water boilers; Nickel-Eintrag aus Wasserkochern ins Trinkwasser

    Energy Technology Data Exchange (ETDEWEB)

    Helmers, E. [Amt fuer Umweltschutz, Stuttgart (Germany). Chemisches Inst.

    1998-07-01

    The EU is planning to drop the threshold value for nickel in drinking water down to 20 {mu}g/l (present German threshold value: 50 {mu}g/l). Since ICP-MS-screenings of spot checks of water cookers were striking with respect to nickel, emissions of electrical water cookers have been investigated systematically within this study. As a result, water cookers with open heating coils are emitting relevant amounts of nickel into the water while it is brought to the boil. Investigation of eight preused water cookers with open heating coils revealed that the boiled water contained more than 50 {mu}g Ni/l in one case, more than 20 {mu}g Ni/l in two cases and, between 10 and 20 {mu}g Ni/l in two more cases, respectively. Removing of the lime by the aid of citric acid is increasing the nickel concentrations by a factor of up to 50 (max. 640 {mu}g/l). A new device was checked in a long-term test. During standard use with tapwater, Ni concentrations fall below the detection limit of 5 {mu}g Ni/l (120 cooking events). However, after removing of the lime, 5 times of cooking were necessary in order to diminish the Ni concentrations below the limit of 20 {mu}g/l. In the case of dionized water Ni concentrations below the limit of 20 {mu}g/l. In the case of deionized water Ni concentrations remained between 94 und 190 {mu}g/l. Health risk assessment: The intake of nickel with beverages made from hot water out of these cookers is in the range of 26 {mu}g/day. Considering an alltogether dietary nickel intake of 130-170 (900) {mu}g/day, this is not beyond the scope. However, according to the fact that nickel allergies (dermatitis) are very frequent (up to 13% of the population), this source should be limited or closed. (orig.) [Deutsch] Aus Anlass der geplanten Absenkung des Trinkwassergrenzwertes fuer Nickel auf 20 {mu}g/l sowie aufgrund von Auffaelligkeiten bei Stichprobenuntersuchungen wurde das Nickel-Emissionsverhalten von elektrischen Wassererhitzern betrachtet. Hierbei erwies sich

  7. Low dose irradiation creep of pure nickel

    International Nuclear Information System (INIS)

    A detailed climb-controlled glide model of low dose irradiation creep has been developed to rationalize irradiation creep data of pure nickel irradiated in a light ion irradiation creep apparatus. Experimental irradiation creep data were obtained to study the effects of initial microstructure and stress on low dose irradiation creep in pure nickel. Pure nickel specimens (99.992% Ni), with three different microstructures, were irradiated with 17 or 15 MeV deuterons at 473 K and stresses ranging from 0.35 to 0.9 of the unirradiated yield stress. Transmission electron microscopy revealed that the microstructure following irradiation to 0.05 dpa consisted of a high density of small dislocation loops, some small voids and network dislocations. The creep model predicted creep rates proportional to the mobile dislocation density and a comparison of experimental irradiation creep rates as a function of homologous stress revealed a dependence on initial microstructure of the magnitude predicted by the measured dislocation densities. The three microstructures that were irradiated consisted of 85% and 25% cold-worked Ni specimens and well-annealed Ni specimens. A weak stress dependence of irradiation creep was observed in 85% cold-worked Ni in agreement with experimental determinations of the stress dependence of irradiation creep by others. The weak stress dependence was shown to be a consequence of the stress independence of the dislocation climb velocity and the weak stress dependence of the barrier removal process. The irradiation creep rate was observed to be proportional to the applied stress. This linear stress dependence was suggested to be due to the stress dependence of the mobile dislocation density. 101 references, 27 figures, 11 tables

  8. Devices for fatigue testing of electroplated nickel (MEMS)

    DEFF Research Database (Denmark)

    Larsen, Kristian Pontoppidan; Ravnkilde, J. T.; Ginnerup, Morten;

    2002-01-01

    In-situ fatigue test devices with integrated electrostatic actuator were fabricated in electroplated nanocrystalline nickel (nano-nickel). The devices feature in-plane approximately pure bending with fixed displacement of the test specimen of the dimensions: widths from 2μm to 3.7μm, a height of ...

  9. Nickel patch test reactivity and the menstrual cycle

    DEFF Research Database (Denmark)

    Rohold, A E; Halkier-Sørensen, L; Thestrup-Pedersen, K;

    1994-01-01

    menstrual cycle. Twenty women with regular periods were tested on day 7-10 and on day 20-24. Ten nickel patch tests with different concentrations were applied using the TRUE test assay, and the threshold concentration of nickel sulphate eliciting an erythematous reaction was determined. Half of the women...

  10. Flash light sintering of nickel nanoparticles for printed electronics

    International Nuclear Information System (INIS)

    In this paper, a sintering process for nickel nanoparticles using flash light irradiation was investigated for multilayer ceramic capacitors, magnetic devices and printed electronics. The existence of a small amount of 10 nm size nanoparticles in the ink significantly improved the flash light absorption and induced the melting and sintering of the nanoparticles. Due to this phenomenon, uniform diameter nickel nanoparticles (50 nm) could not be sintered, while the nickel nanoparticles with varying diameters (5–500 nm) were sintered by flash light irradiation. In order to acquire high electrical conductivity in the sintered nickel nanoparticles, several flash light sintering parameters such as light energy and pulsed light patterns were optimized. Also, the nickel nano-ink was optimized by changing the weight fractions of organic binder in the ink. - Highlights: • Nickel nanoparticle was sintered by flash light irradiation technique. • The existence of 10 nm size nanoparticles improved the flash light absorption. • The melting temperature of the 10 nm size nanoparticles is significantly decreased. • The only nickel nanoparticles with varying diameters (5–500 nm) were sintered. • Several sintering parameters were optimized for conductivity of nickel nanoparticle

  11. Phase analysis of nickel surface layer implanted by aluminium

    International Nuclear Information System (INIS)

    The experimental result of study of microstructure and phase composition in the surface zone of nickel target under intensive implantation of aluminium ions on a vacuum-arc and plasma flow source Raduga-5 are presented. It was established that the fine dispersed intermetallic precipitates Ni3Al and NiAl and the variable composition solid solution of aluminium in nickel are formed

  12. Catalytic Action of Nanoparticle on Electrodeposition of Nickel

    Institute of Scientific and Technical Information of China (English)

    TU Wei-yi; XU Bin-shi; DONG Shi-yun

    2004-01-01

    The electrochemical behavior from n-Al2 O3 or n-SiO2 composite brush plating system and quick nickel solution were investigated using cyclicvoltammetry. The interaction between nanoparticle and matrix metal nickel was researched by X-ray Photoelectron Spectrometry. The electrochemical experimental data indicated that nanoparticles lead to increasing of the current efficiency as well as decreasing of overpotential. The results showed that the nanoparticle took part in the electrode reaction during nickel electrocrystallization and could catalyze the nickel electrodeposition. During the electrocrystallization process, some of nanoparticles were captured effectively on the growing metal surface. As the absorbed nickel atoms were diffusing on metal growth surface, some of them arrived at the interface between the captured nanoparticle and the growing metal surface. The unsaturated bond of oxygen on nanoparticle surface could capture some of the absorbed nickel atoms and form nickel-oxygen chemical bond. It was proved that the chemical bond interaction exists in the interface between nanoparticles surface and matrix metal nickel.

  13. Electric conductivity and nonstoichiometry nature of nickel orthovanadate

    International Nuclear Information System (INIS)

    The nature of nickel orthovanadate nonstoichiometry was determined. It is shown that at low partial pressures of oxygen and high temperatures in Ni3V2O8 removal of oxygen from the lattice occurs with the formation of ionized associates and electrons. Electric conductivity of nickel orthovanadate is determined by electron movement by polaron mechanism. 5 refs., 4 figs

  14. Improvements of Nickel Deposit Characteristics by Pulse Plating

    DEFF Research Database (Denmark)

    Tang, Peter Torben; Leisner, Peter; Møller, Per

    1993-01-01

    Investigation of the properties of electroplated nickel, using both pulse plating and conventional di-rect current (DC), has lead to several interesting improvements of deposit characteristics. Investigated properties include; internal stress, tensile strength, yield stress, elongation, hardness......, throwing power, current efficiency and corrosion resistance (porosity). Experiments have been made with Watts nickel baths, sulphamate baths and a modified Watts bath called W3....

  15. Sensitivity and specificity of the nickel spot (dimethylglyoxime) test

    DEFF Research Database (Denmark)

    Thyssen, Jacob P; Skare, Lizbet; Lundgren, Lennart; Menné, Torkil; Johansen, Jeanne D; Maibach, Howard I; Lidén, Carola

    2010-01-01

    The accuracy of the dimethylglyoxime (DMG) nickel spot test has been questioned because of false negative and positive test reactions. The EN 1811, a European standard reference method developed by the European Committee for Standardization (CEN), is fine-tuned to estimate nickel release around the...

  16. Black holes and beyond

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-02-01

    Belief in the existence of black holes is the ultimate act of faith for a physicist. First suggested by the English clergyman John Michell in the year 1784, the gravitational pull of a black hole is so strong that nothing - not even light - can escape. Gravity might be the weakest of the fundamental forces but black-hole physics is not for the faint-hearted. Black holes present obvious problems for would-be observers because they cannot, by definition, be seen with conventional telescopes - although before the end of the decade gravitational-wave detectors should be able to study collisions between black holes. Until then astronomers can only infer the existence of a black hole from its gravitational influence on other matter, or from the X-rays emitted by gas and dust as they are dragged into the black hole. However, once this material passes through the 'event horizon' that surrounds the black hole, we will never see it again - not even with X-ray specs. Despite these observational problems, most physicists and astronomers believe that black holes do exist. Small black holes a few kilometres across are thought to form when stars weighing more than about two solar masses collapse under the weight of their own gravity, while supermassive black holes weighing millions of solar masses appear to be present at the centre of most galaxies. Moreover, some brave physicists have proposed ways to make black holes - or at least event horizons - in the laboratory. The basic idea behind these 'artificial black holes' is not to compress a large amount of mass into a small volume, but to reduce the speed of light in a moving medium to less than the speed of the medium and so create an event horizon. The parallels with real black holes are not exact but the experiments could shed new light on a variety of phenomena. The first challenge, however, is to get money for the research. One year on from a high-profile meeting on artificial black holes in London, for

  17. Nickel Nanoparticles for Enhancing Carbon Capture

    OpenAIRE

    Gaurav Ashok Bhaduri; Mohammed A. H. Alamiry; Lidija Šiller

    2015-01-01

    Hydration reaction of CO2 is one of the rate limiting steps for CO2 absorption (in aqueous solutions) and aqueous CO2 mineralization. The catalytic activity of nickel nanoparticles (NiNPs) for CO2 hydration is studied at different temperatures, pH, and low CO2 partial pressures to mimic the true flue gas conditions. Results show that NiNPs can work as active catalyst for hydration of CO2 in applications such as CO2 separation and CO2 mineralization. The NiNPs display optimum activity within 2...

  18. Nickel binding sites in histone proteins

    OpenAIRE

    Zoroddu, Maria Antonietta; Peana, Massimiliano Francesco; Solinas, Costantino; Medici, Serenella

    2012-01-01

    Nickel compounds are well known as human carcinogens, though the molecular events that are responsible for this are not well understood. It has been proposed that a crucial element in the mechanism of carcinogenesis is the binding of Ni(II) ions within the cell nucleus. It is known that DNA polymer binds Ni(II) only weakly, leaving the proteins of the cell nucleus as the likely Ni(II) targets. Being histone proteins the most abundant among them, they can be considered the primary sites fo...

  19. Thioetherification via Photoredox/Nickel Dual Catalysis.

    Science.gov (United States)

    Jouffroy, Matthieu; Kelly, Christopher B; Molander, Gary A

    2016-02-19

    Hypervalent alkylsilicates represent new and readily accessible precursors for the generation of alkyl radicals under photoredox conditions. Alkyl radicals generated from such silicates serve as effective hydrogen atom abstractors from thiols, furnishing thiyl radicals. The reactive sulfur species generated in this manner can be funneled into a nickel-mediated cross-coupling cycle employing aromatic bromides to furnish thioethers. The serendipitous discovery of this reaction and its utilization for the thioetherification of various aryl and heteroaryl bromides with a diverse array of thiols is described. The S-H selective H atom abstraction event enables a wide range of functional groups, including those bearing protic moieties, to be tolerated. PMID:26852821

  20. Density of iron-nickel melts

    International Nuclear Information System (INIS)

    Iron-nickel melt density is studied in the wide ranges of concentrations and temperatures using the penetrating gamma radiation method. Mean coordination numbers and interatomic distances have been calculated. Attainment of equilibrium state from the point of view of the melt composition and microvolume structure requires, depending on melting condition, rather long time in some cases, up to several hours. Concentration dependences of density, mean coordination numbers and interatomic distances indicate complex, heterogeneous microstructure of the Fe-Ni melts. In equilibrium the level of heterogeneity as well as the short-range order structure significantly depend on melt composition

  1. Method for regeneration of electroless nickel plating solution

    Science.gov (United States)

    Eisenmann, Erhard T.

    1997-01-01

    An electroless nickel(EN)/hypophosphite plating bath is provided employing acetic acid/acetate as a buffer and which is, as a result, capable of perpetual regeneration while avoiding the production of hazardous waste. A regeneration process is provided to process the spent EN plating bath solution. A concentrated starter and replenishment solution is provided for ease of operation of the plating bath. The regeneration process employs a chelating ion exchange system to remove nickel cations from spent EN plating solution. Phosphites are then removed from the solution by precipitation. The nickel cations are removed from the ion exchange system by elution with hypophosphorous acid and the nickel concentration of the eluate adjusted by addition of nickel salt. The treated solution and adjusted eluate are combined, stabilizer added, and the volume of resulting solution reduced by evaporation to form the bath starter and replenishing solution.

  2. Biosorption of nickel by yeasts in an osmotically unsuitable environment

    Energy Technology Data Exchange (ETDEWEB)

    Breierova, Emilia; Kovarova, Annamaria [SAS, Bratislava (Slovakia). Inst. of Chemistry; Certik, Milan [SUT, Bratislava (Slovakia). Dept. of Biochemical Technology; Gregor, Tomas [Mendel Univ. of Agriculture and Forestry, Brno (Czech Republic)

    2008-11-15

    The tolerance, sorption of nickel(II) ions, and changes in the production and composition of exopolymers of eight yeast strains grown under nickel presence with/without NaCl were studied. Strains of Pichia anomala and Candida maltosa known as the most resistant yeasts against nickel tolerated up to 3 mm Ni{sup 2+}. NaCl addition decreased both the resistance ofthe yeast strains toward nickel ions and the sorption of metal ions into cells. All yeasts absorbed nickel predominantly into exopolymers (glycoproteins) and on the surface of cells. However, while the amount of polysaccharide moieties of exoglycoproteins of most of the resistant yeasts was induced by stress conditions, the ratio polysaccharide/protein in the exopolymers remained unchanged in the sensitive species Cystofilobasidium. The exopolymer composition might play a key role in yeast adaptation to stress conditions caused by heavy metal ions. (orig.)

  3. Synthesis, characterization and properties of hollow nickel phosphide nanospheres

    Energy Technology Data Exchange (ETDEWEB)

    Ni Yonghong; Tao Ali; Hu Guangzhi; Cao Xiaofeng; Wei Xianwen; Yang Zhousheng [College of Chemistry and Materials Science, Anhui Key Laboratory of Functional Molecular Solids, Anhui Normal University, Wuhu 241000 (China)

    2006-10-14

    Nickel phosphide (Ni{sub 12}P{sub 5}) hollow nanospheres with a mean diameter of 100 nm and a shell thickness of 15-20 nm have been successfully prepared by a hydrothermal-microemulsion route, using NaH{sub 2}PO{sub 2} as a phosphorus source. XRD, EDS (HR)TEM, SEM and the SAED pattern were used to characterize the final product. Experiments showed that the as-prepared nickel phosphide hollow nanospheres could selectively catalytically degrade some organic dyes such as methyl red and Safranine T under 254 nm UV light irradiation. At the same time, the nickel phosphide hollow nanospheres showed a stronger ability to promote electron transfer between the glass-carbon electrode and adrenalin than nickel phosphide honeycomb-like particles prepared by a simple hydrothermal route. A possible formation process for nickel phosphide hollow nanospheres was suggested based on the experimental results.

  4. Theromdynamics of carbon in nickel-based multicomponent solid solutions

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, D. J.

    1978-04-01

    The activity coefficient of carbon in nickel, nickel-titanium, nickel-titanium-chromium, nickel-titanium-molybdenum and nickel-titanium-molybdenum-chromium alloys has been measured at 900, 1100 and 1215/sup 0/C. The results indicate that carbon obeys Henry's Law over the range studied (0 to 2 at. percent). The literature for the nickel-carbon and iron-carbon systems are reviewed and corrected. For the activity of carbon in iron as a function of composition, a new relationship based on re-evaluation of the thermodynamics of the CO/CO/sub 2/ equilibrium is proposed. Calculations using this relationship reproduce the data to within 2.5 percent, but the accuracy of the calibrating standards used by many investigators to analyze for carbon is at best 5 percent. This explains the lack of agreement between the many precise sets of data. The values of the activity coefficient of carbon in the various solid solutions are used to calculate a set of parameters for the Kohler-Kaufman equation. The calculations indicate that binary interaction energies are not sufficient to describe the thermodynamics of carbon in some of the nickel-based solid solutions. The results of previous workers for carbon in nickel-iron alloys are completely described by inclusion of ternary terms in the Kohler-Kaufman equation. Most of the carbon solid solution at high temperatures in nickel and nickel-titantium alloys precipitates from solution on quenching in water. The precipitate is composed of very small particles (greater than 2.5 nm) of elemental carbon. The results of some preliminary thermomigration experiments are discussed and recommendations for further work are presented.

  5. Porous titanium-nickel for intervertebral fusion in a sheep model: part 2. Surface analysis and nickel release assessment.

    Science.gov (United States)

    Assad, M; Chernyshov, A V; Jarzem, P; Leroux, M A; Coillard, C; Charette, S; Rivard, C H

    2003-02-15

    Porous titanium-nickel (PTN) devices represent an alternative to traditional cage implants. PTN materials possess an interconnecting network of pores with capillarity properties that may promote bone ingrowth, long-term fixation, and intervertebral fusion without the need for bone grafting. However, their considerable surface area and nickel content may elicit concerns over sensitization potential. Therefore, PTN surface corrosion and nickel release resistance must be carefully studied. To evaluate this possibility, a PTN interbody fusion device (IFD) was compared to a conventional nonporous cage made of TiAlV, a well-known biocompatible biomaterial, in a sheep model. PTN and TiAlV IFDs were inserted at two non-contiguous lumbar sites for 3, 6, and 12 months postsurgery. Their surface was then evaluated by scanning electron microscopy (SEM) combined with backscattered electron analysis (BSE). No evidence of surface corrosion was observed either pre- or postimplantation, regardless of device type. Dosage of nickel ions was also performed with the use of inductively coupled plasma-mass spectrometry (ICP-MS). Blood nickel levels were observed to be within acceptable levels at all postinstrumentation times. Nickel content in PTN-adjacent tissue, as well as in detoxification and remote organs, was equivalent both in PTN-treated and control sheep. Therefore, porous titanium-nickel demonstrated resistance to both in vivo surface corrosion and nickel ion release and compared very well with a conventional titanium implant in the course of a 12-month sheep study. PMID:12516086

  6. Nickel and Cobalt Resistance Engineered in Escherichia coli by Overexpression of Serine Acetyltransferase from the Nickel Hyperaccumulator Plant Thlaspi goesingense

    OpenAIRE

    Freeman, John L; Persans, Michael W.; Nieman, Ken; Salt, David E.

    2005-01-01

    The overexpression of serine acetyltransferase from the Ni-hyperaccumulating plant Thlaspi goesingense causes enhanced nickel and cobalt resistance in Escherichia coli. Furthermore, overexpression of T. goesingense serine acetyltransferase results in enhanced sensitivity to cadmium and has no significant effect on resistance to zinc. Enhanced nickel resistance is directly related to the constitutive overactivation of sulfur assimilation and glutathione biosynthesis, driven by the overproducti...

  7. Virtual black holes

    Science.gov (United States)

    Hawking, S. W.

    1996-03-01

    One would expect spacetime to have a foamlike structure on the Planck scale with a very high topology. If spacetime is simply connected (which is assumed in this paper), the nontrivial homology occurs in dimension two, and spacetime can be regarded as being essentially the topological sum of S2×S2 and K3 bubbles. Comparison with the instantons for pair creation of black holes shows that the S2×S2 bubbles can be interpreted as closed loops of virtual black holes. It is shown that scattering in such topological fluctuations leads to loss of quantum coherence, or in other words, to a superscattering matrix S/ that does not factorize into an S matrix and its adjoint. This loss of quantum coherence is very small at low energies for everything except scalar fields, leading to the prediction that we may never observe the Higgs particle. Another possible observational consequence may be that the θ angle of QCD is zero without having to invoke the problematical existence of a light axion. The picture of virtual black holes given here also suggests that macroscopic black holes will evaporate down to the Planck size and then disappear in the sea of virtual black holes.

  8. Charged Galileon black holes

    CERN Document Server

    Babichev, Eugeny; Hassaine, Mokhtar

    2015-01-01

    We consider an Abelian gauge field coupled to a particular truncation of Horndeski theory. The Galileon field has translation symmetry and couples non minimally both to the metric and the gauge field. When the gauge-scalar coupling is zero the gauge field reduces to a standard Maxwell field. By taking into account the symmetries of the action, we construct charged black hole solutions. Allowing the scalar field to softly break symmetries of spacetime we construct black holes where the scalar field is regular on the black hole event horizon. Some of these solutions can be interpreted as the equivalent of Reissner-Nordstrom black holes of scalar tensor theories with a non trivial scalar field. A self tuning black hole solution found previously is extended to the presence of dyonic charge without affecting whatsoever the self tuning of a large positive cosmological constant. Finally, for a general shift invariant scalar tensor theory we demonstrate that the scalar field Ansatz and method we employ are mathematic...

  9. Joining of boron carbide using nickel interlayer

    International Nuclear Information System (INIS)

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

  10. SYNTHESIS OF NICKEL NANOPOWDERS IN MICROEMULSION

    Institute of Scientific and Technical Information of China (English)

    Desheng Ai; Shinhoo Kang; Xiaming Dai; Hanjung Kwon

    2003-01-01

    @@ Introduction Nanometer-scale crystallites of various metals and nonmetals have attracted a great deal of attention over the past decade. For such crystallites, the physical and chemical properties are heavily dependent on particle size and shape, and, as a result, these materials have a wide range of applications (Ai & Kang, 2003). Monodisperse fine nickel particles are required for high technology applications in alkaline rechargeable batteries, magnetic recording media and chemical catalysts, etc., such as conducting and magnetic inks, and ferrofluids (Glicksman, 1984).Among the various methods for synthesis of ultrafine nickel powders including physical methods such as ball milling,pulsed electrodeposition (PED), thermal plasma, gas deposition methods (GDM), γ-radiation (Wang et al., 1988),and chemical methods such as sonochemical decomposition (Gao et al., 2001), chemical reduction (Illy-Cherrey et al., 2002), microwave hydrothermal method (Komameni et al., 1992), mechanochemical and polyol processing (Baburaj et al., 1997; Hegde et al., 1997), chemical reduction in an aqueous solution (Li et al., 1999; Jung et al., 2003;Degen & Macek, 1999; Syukri et al., 2003) is chosen in the present study because of easy controlling of the size and shape of Ni nanocrystals.

  11. Nickel-titanium alloys: a systematic review

    Directory of Open Access Journals (Sweden)

    Marcelo do Amaral Ferreira

    2012-06-01

    Full Text Available OBJECTIVE: A systematic review on nickel-titanium wires was performed. The strategy was focused on Entrez-PubMed-OLDMEDLINE, Scopus and BioMed Central from 1963 to 2008. METHODS: Papers in English and French describing the behavior of these wires and laboratorial methods to identify crystalline transformation were considered. A total of 29 papers were selected. RESULTS: Nickel-titanium wires show exceptional features in terms of elasticity and shape memory effects. However, clinical applications request a deeper knowledge of these properties in order to allow the professional to use them in a rational manner. In addition, the necessary information regarding each alloy often does not correspond to the information given by the manufacturer. Many alloys called "superelastic" do not present this effect; they just behave as less stiff alloys, with a larger springback if compared to the stainless steel wires. CONCLUSIONS: Laboratory tests are the only means to observe the real behavior of these materials, including temperature transition range (TTR and applied tensions. However, it is also possible to determine in which TTR these alloys change the crystalline structure.

  12. Advanced nickel-hydrogen spacecraft battery development

    Science.gov (United States)

    Coates, Dwaine K.; Fox, Chris L.; Standlee, D. J.; Grindstaff, B. K.

    1994-02-01

    Eagle-Picher currently has several advanced nickel-hydrogen (NiH2) cell component and battery designs under development including common pressure vessel (CPV), single pressure vessel (SPV), and dependent pressure vessel (DPV) designs. A CPV NiH2 battery, utilizing low-cost 64 mm (2.5 in.) cell diameter technology, has been designed and built for multiple smallsat programs, including the TUBSAT B spacecraft which is currently scheduled (24 Nov. 93) for launch aboard a Russian Proton rocket. An advanced 90 mm (3.5 in.) NiH2 cell design is currently being manufactured for the Space Station Freedom program. Prototype 254 mm (10 in.) diameter SPV batteries are currently under construction and initial boilerplate testing has shown excellent results. NiH2 cycle life testing is being continued at Eagle-Picher and IPV cells have currently completed more than 89,000 accelerated LEO cycles at 15% DOD, 49,000 real-time LEO cycles at 30 percent DOD, 37,800 cycles under a real-time LEO profile, 30 eclipse seasons in accelerated GEO, and 6 eclipse seasons in real-time GEO testing at 75 percent DOD maximum. Nickel-metal hydride battery development is continuing for both aerospace and electric vehicle applications. Eagle-Picher has also developed an extensive range of battery evaluation, test, and analysis (BETA) measurement and control equipment and software, based on Hewlett-Packard computerized data acquisition/control hardware.

  13. Aluminium alloys containing iron and nickel

    International Nuclear Information System (INIS)

    The first part of this report addresses mechanism, kinetics and structure factors of aluminium alloys containing iron and nickel in water and high temperature steam. The studied alloys contain from 0.3 to 0.7 per cent of iron, and 0.2 to 1.0 per cent of nickel. Corrosion resistance and corrosion structure have been studied. The experimental installation, process and samples are presented. Corrosion structures in water at 350 C are identified and discussed (structure of corrosion products, structure of metal-oxide interface), and then in steam at different temperatures (350-395 C). Corrosion kinetics is experimentally studied (weight variation in time) in water at 350 C and in steam at different temperatures. Reactions occurring at over-heated steam (more than 400 C) are studied, and the case of welded alloys is also addressed. The second part addresses the metallurgical mechanism and processes influencing aluminium alloy resistance to corrosion by high temperature water as it appeared that separated phases protect the solid solution through a neighbourhood action. In order to avoid deep local corrosions, it seems necessary to multiply protective phases in an as uniform as possible way. Some processes enabling this result are described. They belong to conventional metallurgy or to powder metallurgy (with sintering and extrusion)

  14. The Effects of Additives on the Physical Properties of Electroformed Nickel and on the Stretch of Photoelectroformed Nickel Components

    CERN Document Server

    Allen, D; Garbutt, I; Saumer, M; Dhum, Ch; Schmitt, M; Hoffmann, J E

    2007-01-01

    The process of nickel electroforming is becoming increasingly important in the manufacture of MST products, as it has the potential to replicate complex geometries with extremely high fidelity. Electroforming of nickel uses multi-component electrolyte formulations in order to maximise desirable product properties. In addition to nickel sulphamate (the major electrolyte component), formulation additives can also comprise nickel chloride (to increase nickel anode dissolution), sulphamic acid (to control pH), boric acid (to act as a pH buffer), hardening/levelling agents (to increase deposit hardness and lustre) and wetting agents (to aid surface wetting and thus prevent gas bubbles and void formation). This paper investigates the effects of some of these variables on internal stress and stretch as a function of applied current density.

  15. Evidence for the participation of surface nickel aluminate sites in the steam reforming of methane over nickel/alumina catalysts

    International Nuclear Information System (INIS)

    The specific activities of various Ni/Al2O3 catalysts for the reaction of CH4 with H2O have been obtained and have been shown to vary markedly with catalyst preparation and to differ considerably from the specific activities of pure nickel. This has been explained by suggesting that the unreduced catalysts contain surface nickel aluminate phases which, on reduction, give monodispersed nickel atoms closely associated with alumina sites in addition to metallic crystallites arising from the reduction of nickel oxide. The results of exchange experiments using deuterium and H218O are presented in support of the suggestion that the monodispersed nickel atoms probably participate in the CH4 + H2O reaction

  16. A novel ionic liquid/micro-volume back extraction procedure combined with flame atomic absorption spectrometry for determination of trace nickel in samples of nutritional interest

    Energy Technology Data Exchange (ETDEWEB)

    Dadfarnia, Shayesteh, E-mail: sdadfarnia@yazduni.ac.ir [Department of Chemistry, Faculty of Science, Yazd University, 89195/74, Yazd (Iran, Islamic Republic of); Haji Shabani, Ali Mohammad; Shirani Bidabadi, Mahboubeh; Jafari, Abbas Ali [Department of Chemistry, Faculty of Science, Yazd University, 89195/74, Yazd (Iran, Islamic Republic of)

    2010-01-15

    A simple, highly sensitive and environment-friendly method for the determination of trace amount of nickel ion in different matrices is proposed. In the preconcentration step, the nickel from 10 mL of an aqueous solution was extracted into 500 {mu}L of ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate [C{sub 4}MIM][PF{sub 6}], containing PAN as complexing agent. Subsequently, the PAN complex was back-extracted into 250 {mu}L of nitric acid solution, and 100 {mu}L of it was analyzed by flow injection flame atomic absorption spectrometry (FI-FAAS). The main parameter influencing the extraction and determination of nickel, such as pH, concentration of PAN, extraction time and temperature, ionic strength, and concentration of stripping acid solution, were optimized. An enhancement factor of 40.2 was achieved with 25 mL sample. The limit of detection (LOD) and quantification obtained under the optimum conditions were 12.5 and 41.0 {mu}g L{sup -1}, respectively. To validate the proposed methods two certified reference materials 681-I and BCR No. 288 were analyzed and the results were in good agreement with the certified values. The proposed method was successfully applied to determination of nickel in water samples, rice flour and black tea.

  17. A novel ionic liquid/micro-volume back extraction procedure combined with flame atomic absorption spectrometry for determination of trace nickel in samples of nutritional interest

    International Nuclear Information System (INIS)

    A simple, highly sensitive and environment-friendly method for the determination of trace amount of nickel ion in different matrices is proposed. In the preconcentration step, the nickel from 10 mL of an aqueous solution was extracted into 500 μL of ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate [C4MIM][PF6], containing PAN as complexing agent. Subsequently, the PAN complex was back-extracted into 250 μL of nitric acid solution, and 100 μL of it was analyzed by flow injection flame atomic absorption spectrometry (FI-FAAS). The main parameter influencing the extraction and determination of nickel, such as pH, concentration of PAN, extraction time and temperature, ionic strength, and concentration of stripping acid solution, were optimized. An enhancement factor of 40.2 was achieved with 25 mL sample. The limit of detection (LOD) and quantification obtained under the optimum conditions were 12.5 and 41.0 μg L-1, respectively. To validate the proposed methods two certified reference materials 681-I and BCR No. 288 were analyzed and the results were in good agreement with the certified values. The proposed method was successfully applied to determination of nickel in water samples, rice flour and black tea.

  18. Heavy Metal concentrations in the Sea Snail Rapana venosa (Valenciennes, 1846) from Sinop Coasts of the Black Sea

    OpenAIRE

    BAT, Levent; Gonlaigiir, Gamze; Andae, Miiberra; Öztürk, Meral; Oztürk, Mehmet

    2000-01-01

    Abstract The concentrations of copper, zinc, iron, lead, nickel, manganese and cadmium in the living tissue of the sea snail Rapana venosa (Valenciennes, 1846) from the Sinop coasts of the Black Sea have been measured by atomic absorption spectrophotometer for monitoring metal pollution in the coastal water. A statistically significant difference in the concentrations of all metals was observed among three sampling stations. The results were compared to those of several bivalves and gast...

  19. Tunneling Through Black Rings

    Institute of Scientific and Technical Information of China (English)

    ZHAO Liu

    2007-01-01

    Hawking radiation of black ring solutions to 5-dimensional Einstein-Maxwell-dilaton theory is analyzed by use of the Parikh-Wilczek tunneling method. To get the correct tunneling amplitude and emission rate, we adopt and develop the Angheben-Nadalini-Vanzo-Zerbini covariant approach to cover the effects of rotation and electronic discharge all at once, and the effect of back reaction is also taken into account. This constitutes a unified approach to the tunneling problem. Provided the first law of thermodynamics for black rings holds, the emission rate is proportional to the exponential of the change of Bekenstein-Hawking entropy. Explicit calculation for black ring temperatures agrees exactly with the results obtained via the classical surface gravity method and the quasi-local formalism.

  20. Noncommutative black hole thermodynamics

    International Nuclear Information System (INIS)

    We give a general derivation, for any static spherically symmetric metric, of the relation Th=(K/2π) connecting the black hole temperature (Th) with the surface gravity (K), following the tunneling interpretation of Hawking radiation. This derivation is valid even beyond the semi-classical regime, i.e. when quantum effects are not negligible. The formalism is then applied to a spherically symmetric, stationary noncommutative Schwarzschild space-time. The effects of backreaction are also included. For such a black hole the Hawking temperature is computed in a closed form. A graphical analysis reveals interesting features regarding the variation of the Hawking temperature (including corrections due to noncommutativity and backreaction) with the small radius of the black hole. The entropy and tunneling rate valid for the leading order in the noncommutative parameter are calculated. We also show that the noncommutative Bekenstein-Hawking area law has the same functional form as the usual one

  1. Turbulent black holes.

    Science.gov (United States)

    Yang, Huan; Zimmerman, Aaron; Lehner, Luis

    2015-02-27

    We demonstrate that rapidly spinning black holes can display a new type of nonlinear parametric instability-which is triggered above a certain perturbation amplitude threshold-akin to the onset of turbulence, with possibly observable consequences. This instability transfers from higher temporal and azimuthal spatial frequencies to lower frequencies-a phenomenon reminiscent of the inverse cascade displayed by (2+1)-dimensional fluids. Our finding provides evidence for the onset of transitory turbulence in astrophysical black holes and predicts observable signatures in black hole binaries with high spins. Furthermore, it gives a gravitational description of this behavior which, through the fluid-gravity duality, can potentially shed new light on the remarkable phenomena of turbulence in fluids. PMID:25768746

  2. Black Hole Bose Condensation

    International Nuclear Information System (INIS)

    General consensus on the nature of the degrees of freedom responsible for the black hole entropy remains elusive despite decades of effort dedicated to the problem. Different approaches to quantum gravity disagree in their description of the microstates and, more significantly, in the statistics used to count them. In some approaches (string theory, AdS/CFT) the elementary degrees of freedom are indistinguishable, whereas they must be treated as distinguishable in other approaches to quantum gravity (eg., LQG) in order to recover the Bekenstein-Hawking area-entropy law. However, different statistics will imply different behaviors of the black hole outside the thermodynamic limit. We illustrate this point by quantizing the Bañados-Teitelboim-Zanelli (BTZ) black hole, for which we argue that Bose condensation will occur leading to a cold, stable remnant

  3. Black Hole Bose Condensation

    Science.gov (United States)

    Vaz, Cenalo; Wijewardhana, L. C. R.

    2013-12-01

    General consensus on the nature of the degrees of freedom responsible for the black hole entropy remains elusive despite decades of effort dedicated to the problem. Different approaches to quantum gravity disagree in their description of the microstates and, more significantly, in the statistics used to count them. In some approaches (string theory, AdS/CFT) the elementary degrees of freedom are indistinguishable, whereas they must be treated as distinguishable in other approaches to quantum gravity (eg., LQG) in order to recover the Bekenstein-Hawking area-entropy law. However, different statistics will imply different behaviors of the black hole outside the thermodynamic limit. We illustrate this point by quantizing the Bañados-Teitelboim-Zanelli (BTZ) black hole, for which we argue that Bose condensation will occur leading to a "cold", stable remnant.

  4. Merging Black Holes

    Science.gov (United States)

    Centrella, Joan

    2012-01-01

    The final merger of two black holes is expected to be the strongest source of gravitational waves for both ground-based detectors such as LIGO and VIRGO, as well as future. space-based detectors. Since the merger takes place in the regime of strong dynamical gravity, computing the resulting gravitational waveforms requires solving the full Einstein equations of general relativity on a computer. For many years, numerical codes designed to simulate black hole mergers were plagued by a host of instabilities. However, recent breakthroughs have conquered these instabilities and opened up this field dramatically. This talk will focus on.the resulting 'gold rush' of new results that is revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wave detection, testing general relativity, and astrophysics

  5. Rotating Black Droplet

    CERN Document Server

    Fischetti, Sebastian

    2013-01-01

    We construct the gravitational dual, in the Unruh state, of the "jammed" phase of a CFT at strong coupling and infinite N on a fixed five-dimensional rotating Myers-Perry black hole with equal angular momenta. When the angular momenta are all zero, the solution corresponds to the five-dimensional generalization of the solution first studied by Figueras, Lucietti, and Wiseman. In the extremal limit, when the angular momenta of the Myers-Perry black hole are maximum, the Unruh, Boulware and Hartle-Hawking states degenerate. We give a detailed analysis of the corresponding holographic stress energy tensor for all values of the angular momenta, finding it to be regular at the horizon in all cases. We compare our results with existent literature on thermal states of free field theories on black hole backgrounds.

  6. Turbulent Black Holes

    CERN Document Server

    Yang, Huan; Lehner, Luis

    2014-01-01

    We show that rapidly-spinning black holes can display turbulent gravitational behavior which is mediated by a new type of parametric instability. This instability transfers energy from higher temporal and azimuthal spatial frequencies to lower frequencies--- a phenomenon reminiscent of the inverse energy cascade displayed by 2+1-dimensional turbulent fluids. Our finding reveals a path towards gravitational turbulence for perturbations of rapidly-spinning black holes, and provides the first evidence for gravitational turbulence in an asymptotically flat spacetime. Interestingly, this finding predicts observable gravitational wave signatures from such phenomena in black hole binaries with high spins and gives a gravitational description of turbulence relevant to the fluid-gravity duality.

  7. Turbulent Black Holes

    Science.gov (United States)

    Yang, Huan; Zimmerman, Aaron; Lehner, Luis

    2015-02-01

    We demonstrate that rapidly spinning black holes can display a new type of nonlinear parametric instability—which is triggered above a certain perturbation amplitude threshold—akin to the onset of turbulence, with possibly observable consequences. This instability transfers from higher temporal and azimuthal spatial frequencies to lower frequencies—a phenomenon reminiscent of the inverse cascade displayed by (2 +1 )-dimensional fluids. Our finding provides evidence for the onset of transitory turbulence in astrophysical black holes and predicts observable signatures in black hole binaries with high spins. Furthermore, it gives a gravitational description of this behavior which, through the fluid-gravity duality, can potentially shed new light on the remarkable phenomena of turbulence in fluids.

  8. Slowly balding black holes

    International Nuclear Information System (INIS)

    The 'no-hair' theorem, a key result in general relativity, states that an isolated black hole is defined by only three parameters: mass, angular momentum, and electric charge; this asymptotic state is reached on a light-crossing time scale. We find that the no-hair theorem is not formally applicable for black holes formed from the collapse of a rotating neutron star. Rotating neutron stars can self-produce particles via vacuum breakdown forming a highly conducting plasma magnetosphere such that magnetic field lines are effectively ''frozen in'' the star both before and during collapse. In the limit of no resistivity, this introduces a topological constraint which prohibits the magnetic field from sliding off the newly-formed event horizon. As a result, during collapse of a neutron star into a black hole, the latter conserves the number of magnetic flux tubes NB=eΦ∞/(πc(ℎ/2π)), where Φ∞≅2π2BNSRNS3/(PNSc) is the initial magnetic flux through the hemispheres of the progenitor and out to infinity. We test this theoretical result via 3-dimensional general relativistic plasma simulations of rotating black holes that start with a neutron star dipole magnetic field with no currents initially present outside the event horizon. The black hole's magnetosphere subsequently relaxes to the split-monopole magnetic field geometry with self-generated currents outside the event horizon. The dissipation of the resulting equatorial current sheet leads to a slow loss of the anchored flux tubes, a process that balds the black hole on long resistive time scales rather than the short light-crossing time scales expected from the vacuum no-hair theorem.

  9. Slowly balding black holes

    Science.gov (United States)

    Lyutikov, Maxim; McKinney, Jonathan C.

    2011-10-01

    The “no-hair” theorem, a key result in general relativity, states that an isolated black hole is defined by only three parameters: mass, angular momentum, and electric charge; this asymptotic state is reached on a light-crossing time scale. We find that the no-hair theorem is not formally applicable for black holes formed from the collapse of a rotating neutron star. Rotating neutron stars can self-produce particles via vacuum breakdown forming a highly conducting plasma magnetosphere such that magnetic field lines are effectively “frozen in” the star both before and during collapse. In the limit of no resistivity, this introduces a topological constraint which prohibits the magnetic field from sliding off the newly-formed event horizon. As a result, during collapse of a neutron star into a black hole, the latter conserves the number of magnetic flux tubes NB=eΦ∞/(πcℏ), where Φ∞≈2π2BNSRNS3/(PNSc) is the initial magnetic flux through the hemispheres of the progenitor and out to infinity. We test this theoretical result via 3-dimensional general relativistic plasma simulations of rotating black holes that start with a neutron star dipole magnetic field with no currents initially present outside the event horizon. The black hole’s magnetosphere subsequently relaxes to the split-monopole magnetic field geometry with self-generated currents outside the event horizon. The dissipation of the resulting equatorial current sheet leads to a slow loss of the anchored flux tubes, a process that balds the black hole on long resistive time scales rather than the short light-crossing time scales expected from the vacuum no-hair theorem.

  10. Black holes and beyond

    International Nuclear Information System (INIS)

    The black hole information paradox forces us into a strange situation: we must find a way to break the semiclassical approximation in a domain where no quantum gravity effects would normally be expected. Traditional quantizations of gravity do not exhibit any such breakdown, and this forces us into a difficult corner: either we must give up quantum mechanics or we must accept the existence of troublesome ‘remnants’. In string theory, however, the fundamental quanta are extended objects, and it turns out that the bound states of such objects acquire a size that grows with the number of quanta in the bound state. The interior of the black hole gets completely altered to a ‘fuzzball’ structure, and information is able to escape in radiation from the hole. The semiclassical approximation can break at macroscopic scales due to the large entropy of the hole: the measure in the path integral competes with the classical action, instead of giving a subleading correction. Putting this picture of black hole microstates together with ideas about entangled states leads to a natural set of conjectures on many long-standing questions in gravity: the significance of Rindler and de Sitter entropies, the notion of black hole complementarity, and the fate of an observer falling into a black hole. - Highlights: ► The information paradox is a serious problem. ► To solve it we need to find ‘hair’ on black holes. ► In string theory we find ‘hair’ by the fuzzball construction. ► Fuzzballs help to resolve many other issues in gravity.

  11. Exact solutions of higher dimensional black holes

    CERN Document Server

    Tomizawa, Shinya

    2011-01-01

    We review exact solutions of black holes in higher dimensions, focusing on asymptotically flat black hole solutions and Kaluza-Klein type black hole solutions. We also summarize some properties which such black hole solutions reveal.

  12. The solubility and sorption of nickel and niobium under high pH conditions

    International Nuclear Information System (INIS)

    The solubilities of nickel and niobium were measured in a range of cement-equilibrated waters. For nickel the effects of cellulose degradation products and of chloride were examined and the dependence of nickel solubility on pH was measured. The sorption of nickel and niobium on to cement representative of the ''near field'' of a radioactive waste repository was also measured. (author)

  13. Black light photography

    Energy Technology Data Exchange (ETDEWEB)

    Lisin, M.A. [Koon-Hall-Adrian Metallurgical, Portland, OR (United States)

    1996-11-01

    Black light photography of fluorescent penetrant and wet fluorescent magnetic particle indications can yield spectacular and useful results. The technique provides a lasting record of a flaw`s severity and location, as well as its physical relation to other components and important features. The procedures are easily learned and do not require sophisticated apparatus. In fact, equipment costs can often be justified on the basis of a single application. Using the techniques described in this article, black light photography can be a cost-effective, informative NDT tool.

  14. Noncommutative solitonic black hole

    International Nuclear Information System (INIS)

    We investigate solitonic black hole solutions in three-dimensional noncommutative spacetime. We do this in gravity with a negative cosmological constant coupled to a scalar field. Noncommutativity is realized with the Moyal product which is expanded up to first order in the noncommutativity parameter in two spatial directions. With numerical simulation we study the effect of noncommutativity by increasing the value of the noncommutativity parameter starting from commutative solutions. We find that even a regular soliton solution in the commutative case becomes a black hole solution when the noncommutativity parameter reaches a certain value. (paper)

  15. Noncommutative solitonic black hole

    Science.gov (United States)

    Chang-Young, Ee; Kimm, Kyoungtae; Lee, Daeho; Lee, Youngone

    2012-05-01

    We investigate solitonic black hole solutions in three-dimensional noncommutative spacetime. We do this in gravity with a negative cosmological constant coupled to a scalar field. Noncommutativity is realized with the Moyal product which is expanded up to first order in the noncommutativity parameter in two spatial directions. With numerical simulation we study the effect of noncommutativity by increasing the value of the noncommutativity parameter starting from commutative solutions. We find that even a regular soliton solution in the commutative case becomes a black hole solution when the noncommutativity parameter reaches a certain value.

  16. Superfluid Black Holes

    CERN Document Server

    Hennigar, Robie A; Tjoa, Erickson

    2016-01-01

    We present what we believe is the first example of a "$\\lambda$-line" phase transition in black hole thermodynamics. This is a line of (continuous) second order phase transitions which in the case of liquid $^4$He marks the onset of superfluidity. The phase transition occurs for a class of asymptotically AdS hairy black holes in Lovelock gravity where a real scalar field is conformally coupled to gravity. We discuss the origin of this phase transition and outline the circumstances under which it (or generalizations of it) could occur.

  17. Virtual Black Holes

    OpenAIRE

    Hawking, Stephen W.

    1995-01-01

    One would expect spacetime to have a foam-like structure on the Planck scale with a very high topology. If spacetime is simply connected (which is assumed in this paper), the non-trivial homology occurs in dimension two, and spacetime can be regarded as being essentially the topological sum of $S^2\\times S^2$ and $K3$ bubbles. Comparison with the instantons for pair creation of black holes shows that the $S^2\\times S^2$ bubbles can be interpreted as closed loops of virtual black holes. It is ...

  18. Dancing with black holes

    CERN Document Server

    Aarseth, Sverre J

    2007-01-01

    We describe efforts over the last six years to implement regularization methods suitable for studying one or more interacting black holes by direct N-body simulations. Three different methods have been adapted to large-N systems: (i) Time-Transformed Leapfrog, (ii) Wheel-Spoke, and (iii) Algorithmic Regularization. These methods have been tried out with some success on GRAPE-type computers. Special emphasis has also been devoted to including post-Newtonian terms, with application to moderately massive black holes in stellar clusters. Some examples of simulations leading to coalescence by gravitational radiation will be presented to illustrate the practical usefulness of such methods.

  19. Characterizing Black Hole Mergers

    Science.gov (United States)

    Baker, John; Boggs, William Darian; Kelly, Bernard

    2010-01-01

    Binary black hole mergers are a promising source of gravitational waves for interferometric gravitational wave detectors. Recent advances in numerical relativity have revealed the predictions of General Relativity for the strong burst of radiation generated in the final moments of binary coalescence. We explore features in the merger radiation which characterize the final moments of merger and ringdown. Interpreting the waveforms in terms of an rotating implicit radiation source allows a unified phenomenological description of the system from inspiral through ringdown. Common features in the waveforms allow quantitative description of the merger signal which may provide insights for observations large-mass black hole binaries.

  20. Scattering from black holes

    Energy Technology Data Exchange (ETDEWEB)

    Futterman, J.A.H.; Handler, F.A.; Matzner, R.A.

    1987-01-01

    This book provides a comprehensive treatment of the propagation of waves in the presence of black holes. While emphasizing intuitive physical thinking in their treatment of the techniques of analysis of scattering, the authors also include chapters on the rigorous mathematical development of the subject. Introducing the concepts of scattering by considering the simplest, scalar wave case of scattering by a spherical (Schwarzschild) black hole, the book then develops the formalism of spin weighted spheroidal harmonics and of plane wave representations for neutrino, electromagnetic, and gravitational scattering. Details and results of numerical computations are given. The techniques involved have important applications (references are given) in acoustical and radar imaging.

  1. Scattering from black holes

    International Nuclear Information System (INIS)

    This book provides a comprehensive treatment of the propagation of waves in the presence of black holes. While emphasizing intuitive physical thinking in their treatment of the techniques of analysis of scattering, the authors also include chapters on the rigorous mathematical development of the subject. Introducing the concepts of scattering by considering the simplest, scalar wave case of scattering by a spherical (Schwarzschild) black hole, the book then develops the formalism of spin weighted spheroidal harmonics and of plane wave representations for neutrino, electromagnetic, and gravitational scattering. Details and results of numerical computations are given. The techniques involved have important applications (references are given) in acoustical and radar imaging

  2. Acoustic black holes

    CERN Document Server

    Visser, M

    1999-01-01

    Acoustic propagation in a moving fluid provides a conceptually clean and powerful analogy for understanding black hole physics. As a teaching tool, the analogy is useful for introducing students to both General Relativity and fluid mechanics. As a research tool, the analogy helps clarify what aspects of the physics are kinematics and what aspects are dynamics. In particular, Hawking radiation is a purely kinematical effect, whereas black hole entropy is intrinsically dynamical. Finally, I discuss the fact that with present technology acoustic Hawking radiation is almost experimentally testable.

  3. Are Black Holes Springy?

    CERN Document Server

    Good, Michael R R

    2014-01-01

    A $(3+1)$-dimensional asymptotically flat Kerr black hole angular speed $\\Omega_+$ can be used to define an effective spring constant, $k=m\\Omega_+^2$. Its maximum value is the Schwarzschild surface gravity, $k = \\kappa $, which rapidly weakens as the black hole spins down and the temperature increases. The Hawking temperature is expressed in terms of the spring constant: $2\\pi T = \\kappa - k$. Hooke's law, in the extremal limit, provides the force $F = 1/4$, which is consistent with the conjecture of maximum force in general relativity.

  4. Black-pigmented sputum

    Directory of Open Access Journals (Sweden)

    Rafael Martínez-Girón

    2013-01-01

    Full Text Available Black-pigmented sputum, also called "melanoptysis," is a symptom that may be observed in certain pathologies such us coal workers′ pneumoconiosis (anthracosis. The cavitation and liquefaction of a fibrosed mass by an infectious process (tuberculosis, infections by anaerobes, etc. or by ischemic necrosis may cause expectoration of a blackish secretion. We report the case of a patient with labor precedents as a coal worker, from whom abundant black sputum was obtained in the course of an incidental expectoration. Cyto-histological findings are shown and a differential diagnosis is established.

  5. Horndeski black hole geodesics

    CERN Document Server

    Tretyakova, D A

    2016-01-01

    We examine geodesics for the scalar-tensor black holes in the Horndeski-Galileon framework. Our analysis shows that first kind relativistic orbits may not be present within some model parameters range. This is a highly pathological behavior contradicting to the black hole accretion and Solar System observations. We also present a new (although very similar to those previously known) solution, which contains the orbits we expect from a compact object, admits regular scalar field at the horizon and and can fit into the known stability criteria.

  6. Reflections on a Black Mirror

    CERN Document Server

    Good, Michael R R

    2016-01-01

    A black mirror is an accelerated boundary that produces particles in an exact correspondence to an evaporating black hole. We investigate the spectral dynamics of the particle creation during the formation process.

  7. The black hole final state

    OpenAIRE

    Horowitz, Gary T.; Maldacena, Juan

    2003-01-01

    We propose that in quantum gravity one needs to impose a final state boundary condition at black hole singularities. This resolves the apparent contradiction between string theory and semiclassical arguments over whether black hole evaporation is unitary.

  8. Quantum aspects of black holes

    CERN Document Server

    2015-01-01

    Beginning with an overview of the theory of black holes by the editor, this book presents a collection of ten chapters by leading physicists dealing with the variety of quantum mechanical and quantum gravitational effects pertinent to black holes. The contributions address topics such as Hawking radiation, the thermodynamics of black holes, the information paradox and firewalls, Monsters, primordial black holes, self-gravitating Bose-Einstein condensates, the formation of small black holes in high energetic collisions of particles, minimal length effects in black holes and small black holes at the Large Hadron Collider. Viewed as a whole the collection provides stimulating reading for researchers and graduate students seeking a summary of the quantum features of black holes.

  9. Conquering the Black Girl Blues.

    Science.gov (United States)

    Jones, Lani Valencia; Guy-Sheftall, Beverly

    2015-10-01

    An examination of the literature on epidemiology, etiology, and use of services for this population reveals an insufficient application of culturally congruent approaches to intervening with black women. An exploration of the social work practice literature and other relevant fields indicate that black feminist perspectives offer the opportunity to gain a clearer understanding of the intersection and influence of oppression among black women struggling with psychiatric issues and provide a useful framework for mental health practice with this population. This article discusses the evolving black feminist thought and summarizes the scholarship on black women's mental health services needs and utilization issues. The article includes a discussion of black feminisms as an emerging mental health perspective, arguing that black feminist perspectives in therapy provide an ideal framework for services that are responsive to the values and health needs of black women. The article concludes with a case vignette that illustrates some of its points. PMID:26489355

  10. Phytoremediation of cadmium and nickel by Spirodela polyrhiza

    International Nuclear Information System (INIS)

    Heavy metal pollution in surface and groundwater has considerably increased in the last few years. It is essential to have an effective removal mechanism of these toxic metals. Current research includes the need to develop environment friendly and cost effective technologies for removing heavy metals from water. In several studies cadmium and nickel have been considerably removed using phytoremediation. The removal efficiency of cadmium and nickel by Spirodela polyrhiza, common duckweed has been examined in the present study for 3 different concentrations of cadmium (1, 2 and 3 mg/L) and nickel (4, 5 and 6 mg/L). Two sets of experiments for cadmium and nickel were conducted separately. Effect of metal toxicity on Spirodela polyrhiza was evaluated in terms of relative growth factor and cadmium was found to be more toxic than nickel. Under experimental condition BCF value for cadmium removal was more than >1000 in all the 3 concentrations of cadmium. But the BCF value was found to be more than > 1000 only when input nickel concentration was 4 mg/L during phytoremediation process. Experimental results suggest that Spirodela polyrhiza has the potential of accumulating cadmium and nickel from aqueous solution at lower metal concentration. (author)

  11. Influence of nickel speciation on electrokinetic sediment remediation efficiency

    Directory of Open Access Journals (Sweden)

    Rajić Ljiljana

    2011-01-01

    Full Text Available This article presents a bench-scale investigation of nickel removal during electrokinetic (EK remediation of sediment, and the dependency of removal efficacies upon the speciation of the metal, as influenced by the duration of the nickel-sediment interaction. The sediment used in this study was from the Grand Backa canal (Vojvodina, Republic of Serbia. The sediment used is anaerobic and the nickel pollution has been aged for several years, so it is mostly sorbed by sulphides and organic mater (57%. In EXP I, conventional EK remediation was conducted on this sediment for 7 days, but was ineffective (0% removal. EXP II investigated the influence of the duration of nickel sorption onto the sediment, by contaminating the sediment with additional nickel. In this sediment, nickel appeared mainly in the most mobile, acid-soluble fraction, and was thus available for migration towards the cathode. Consequently, conventional EK remediation of this sediment resulted in significantly better nickel removal (23% than EXP I. During EXP III, the same spiked sediment was investigated using an increased applied current density, with no significant increase in removal efficacy. This study demonstrates that metal-sediment interaction duration affects efficacy of metal removal during EK remediation.

  12. Preparation of fine Ni powders from nickel hydrazine complex

    International Nuclear Information System (INIS)

    Fine nickel powders with narrow size distribution have been prepared from the reduction of nickel hydrazine complexes in aqueous solution. The pure nickel hydrazine complexes, [Ni(N2H4)3]Cl2 were prepared with the molar ratio of N2H4/Ni2+ = 4.5, while a mixture of complexes, such as Ni(N2H4)2Cl2, [Ni(N2H4)3]Cl2, and [Ni(NH3)6]Cl2 were formed with N2H4/Ni2+ 2+ to metallic Ni powder proceeded via the formation of nickel hydroxide which was reduced by hydrazine liberated from the ligand exchange reaction between the nickel hydrazine complex and NaOH. The standard deviation of the particle size decreased with the decreasing molar concentration of nickel hydrazine complex while the mean particle size increased. As the amount of hydrazine increased, the surface roughness of the particles was improved significantly due to the catalytic decomposition of the excess hydrazine at the surface of the nickel particle. It was found that average particle size could be controlled from 150 to 380 nm by adjusting the reaction molar ratio and temperature

  13. Specification and prediction of nickel mobilization using artificial intelligence methods

    Science.gov (United States)

    Gholami, Raoof; Ziaii, Mansour; Ardejani, Faramarz; Maleki, Shahoo

    2011-12-01

    Groundwater and soil pollution from pyrite oxidation, acid mine drainage generation, and release and transport of toxic metals are common environmental problems associated with the mining industry. Nickel is one toxic metal considered to be a key pollutant in some mining setting; to date, its formation mechanism has not yet been fully evaluated. The goals of this study are 1) to describe the process of nickel mobilization in waste dumps by introducing a novel conceptual model, and 2) to predict nickel concentration using two algorithms, namely the support vector machine (SVM) and the general regression neural network (GRNN). The results obtained from this study have shown that considerable amount of nickel concentration can be arrived into the water flow system during the oxidation of pyrite and subsequent Acid Drainage (AMD) generation. It was concluded that pyrite, water, and oxygen are the most important factors for nickel pollution generation while pH condition, SO4, HCO3, TDS, EC, Mg, Fe, Zn, and Cu are measured quantities playing significant role in nickel mobilization. SVM and GRNN have predicted nickel concentration with a high degree of accuracy. Hence, SVM and GRNN can be considered as appropriate tools for environmental risk assessment.

  14. [Nickel - role in human organism and toxic effects].

    Science.gov (United States)

    Zdrojewicz, Zygmunt; Popowicz, Ewa; Winiarski, Jacek

    2016-08-01

    The aim of this study is to familiarize the Role of nickel in the Environment and in living organisms. This metal is widely used in many fields such as electrical engineering, medicine, Jewellery or Automotive Industry. Furthermore, it's an important part of our food. As the central atom of bacterial enzymes it participates in degradation of urea.. Nickel is also an micronutritient essential for proper functioning of the human body, as it increases hormonal activity and is involved in lipid metabolism. This metal makes it's way to the human body through respiratory tract, digestive system and skin. Large doses of nickel or prolonged contact with it could cause a variety of side effects. Harmfull effects of Nickel are genotoxicity haematotoxicity, teratogenicity, immunotoxicity and carcinogenicity. The population of people allergic to nickel is growing, it occcurs much more often to the women and it can appear in many way. Hypersensitivity to nickel can also be occupational. Due to the increasing prevalence of allergies to nickel. European regulations have been introduced to reduce the content of this metal in products of everyday usage. In countries which have fulfilled the above-mentioned law, the plunge of hypersensitivities has been observed. PMID:27591452

  15. Synthesis of nickel and nickel oxide nanoparticles via heat-treatment of simple octanoate precursor

    International Nuclear Information System (INIS)

    Nickel oxide nanoparticles have been synthesized via heat-treatment of a new precursor nickel octanoate Ni(octa)2; (octa = octanoate); in the range of 400-900 oC. The effect of calcination temperature on particle size has been investigated. When the calcinations were conducted in air from 400 to 900 oC, the precursor Ni(octa)2 was first changed to Ni, then to NiO. When calcined in argon atmosphere, Ni(octa)2 was directly converted into pure Ni at as low as 500 oC. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infrared (FT-IR) spectroscopy. The synthesized NiO nanoparticles have quasi-spherical particles with size of about 24 nm. The optical absorption band gap of NiO nanoparticles is 3.41 eV.

  16. Black Hole Evaporation. A Survey

    OpenAIRE

    Benachenhou, Farid

    1994-01-01

    This thesis is a review of black hole evaporation with emphasis on recent results obtained for two dimensional black holes. First, the geometry of the most general stationary black hole in four dimensions is described and some classical quantities are defined. Then, a derivation of the spectrum of the radiation emitted during the evaporation is presented. In section four, a two dimensional model which has black hole solutions is introduced, the so-called CGHS model. These two dimensional blac...

  17. Towards noncommutative quantum black holes

    International Nuclear Information System (INIS)

    In this paper we study noncommutative black holes. We use a diffeomorphism between the Schwarzschild black hole and the Kantowski-Sachs cosmological model, which is generalized to noncommutative minisuperspace. Through the use of the Feynman-Hibbs procedure we are able to study the thermodynamics of the black hole, in particular, we calculate the Hawking's temperature and entropy for the noncommutative Schwarzschild black hole

  18. Towards Noncommutative Quantum Black Holes

    OpenAIRE

    Lopez-Dominguez, J. C.; Obregon, O.; Ramirez, C.; Sabido, M.

    2006-01-01

    In this paper we study noncommutative black holes. We use a diffeomorphism between the Schwarzschild black hole and the Kantowski-Sachs cosmological model, which is generalized to noncommutative minisuperspace. Through the use of the Feynman-Hibbs procedure we are able to study the thermodynamics of the black hole, in particular, we calculate the Hawking's temperature and entropy for the noncommutative Schwarzschild black hole.

  19. Brane-World Black Holes

    CERN Document Server

    Chamblin, A; Reall, H S

    2000-01-01

    Gravitational collapse of matter trapped on a brane will produce a black hole on the brane. We discuss such black holes in the models of Randall and Sundrum where our universe is viewed as a domain wall in five dimensional anti-de Sitter space. We present evidence that a non-rotating uncharged black hole on the domain wall is described by a ``black cigar'' solution in five dimensions.

  20. Brane-world black holes

    Science.gov (United States)

    Chamblin, A.; Hawking, S. W.; Reall, H. S.

    2000-03-01

    Gravitational collapse of matter trapped on a brane will produce a black hole on the brane. We discuss such black holes in the models of Randall and Sundrum where our universe is viewed as a domain wall in five-dimensional anti-de Sitter space. We present evidence that a non-rotating uncharged black hole on the domain wall is described by a ``black cigar'' solution in five dimensions.

  1. Black Holes in Higher Dimensions

    Directory of Open Access Journals (Sweden)

    Reall Harvey S.

    2008-09-01

    Full Text Available We review black-hole solutions of higher-dimensional vacuum gravity and higher-dimensional supergravity theories. The discussion of vacuum gravity is pedagogical, with detailed reviews of Myers–Perry solutions, black rings, and solution-generating techniques. We discuss black-hole solutions of maximal supergravity theories, including black holes in anti-de Sitter space. General results and open problems are discussed throughout.

  2. Black Hole: The Interior Spacetime

    CERN Document Server

    Ong, Yen Chin

    2016-01-01

    The information loss paradox is often discussed from the perspective of the observers who stay outside of a black hole. However, the interior spacetime of a black hole can be rather nontrivial. We discuss the open problems regarding the volume of a black hole, and whether it plays any role in information storage. We also emphasize the importance of resolving the black hole singularity, if one were to resolve the information loss paradox.

  3. Inhalation carcinogenicity study with nickel metal powder in Wistar rats

    International Nuclear Information System (INIS)

    Epidemiological studies of nickel refinery workers have demonstrated an association between increased respiratory cancer risk and exposure to certain nickel compounds (later confirmed in animal studies). However, the lack of an association found in epidemiological analyses for nickel metal remained unconfirmed for lack of robust animal inhalation studies. In the present study, Wistar rats were exposed by whole-body inhalation to 0, 0.1, 0.4, and 1.0 mg Ni/m3 nickel metal powder (MMAD = 1.8 μm, GSD = 2.4 μm) for 6 h/day, 5 days/week for up to 24 months. A subsequent six-month period without exposures preceded the final euthanasia. High mortality among rats exposed to 1.0 mg Ni/m3 nickel metal resulted in the earlier termination of exposures in this group. The exposure level of 0.4 mg Ni/m3 was established as the MTD for the study. Lung alterations associated with nickel metal exposure included alveolar proteinosis, alveolar histiocytosis, chronic inflammation, and bronchiolar-alveolar hyperplasia. No increased incidence of neoplasm of the respiratory tract was observed. Adrenal gland pheochromocytomas (benign and malignant) in males and combined cortical adenomas/carcinomas in females were induced in a dose-dependent manner by the nickel metal exposure. The incidence of pheochromocytomas was statistically increased in the 0.4 mg Ni/m3 male group. Pheochromocytomas appear to be secondary to the lung toxicity associated with the exposure rather than being related to a direct nickel effect on the adrenal glands. The incidence of cortical tumors among 0.4 mg Ni/m3 females, although statistically higher compared to the concurrent controls, falls within the historical control range; therefore, in the present study, this tumor is of uncertain relationship to nickel metal exposure. The lack of respiratory tumors in the present animal study is consistent with the findings of the epidemiological studies

  4. Synthesis and Characterization of Nickel-Alumina Composites from Recycled Nickel Powder

    OpenAIRE

    Karayannis, V. G.; Moutsatsou, A. K.

    2012-01-01

    The recycling of metallic waste to create more valuable materials and their valorization into upgraded metal-based composites constitutes an important field of study. The composite industry nowadays considers environmental improvements as important as other properties of the materials. In the present paper, nickel powder was recycled from ferrous scrap, a low-cost and largely available material, by an effective hydrometallurgical recovery process. Then, this recycled powder was successfully u...

  5. ELECTROCHEMICAL PREPARATION OF COPPER-NICKEL AND COPPER-NICKEL- MANGANESE ALLOYS AND CHARACTERIZATION

    OpenAIRE

    Pathak, R. K.; Neha Deshmukh

    2015-01-01

    lectrochemical preparation of binary alloy of ECu-Ni from acid sulphate bath containing citric acid using potentiostatic method. The effects of alloy composition were monitored. Copper is widely used in industry, because of its good thermal conductivity and mechanical properties. The addition of Nickel and Manganese to Copper improves its strength and durability and also the resistance to corrosion and erosion. Corrosion controls of metal have technical environmental and economical impo...

  6. Blacks and the Women's Movement.

    Science.gov (United States)

    Loiacono, Stephanie

    1989-01-01

    Although Black female leaders were influential in creating the modern women's movement, feminism has evolved differently for both Black and White women. Suggests that, although Black women have struggled largely against racial and economic inequalities, women of all colors and backgrounds should embrace their diversity and unite to oppose racism…

  7. The Strengths of Black Families.

    Science.gov (United States)

    Hill, Robert B.

    This report identifies and analyzes five strengths of black families: adaptability roles, strong kinship bonds, strong work orientation, strong religious orientation, and achievement orientation. These five characteristics have been functional for the survival, advancement, and stability of black families. Most discussions of black families tend…

  8. Black carbon in marine sediments

    NARCIS (Netherlands)

    Middelburg, J.J.; Nieuwenhuize, J.; Van Breugel, P.

    1999-01-01

    Concentrations of black carbon were determined for a number of marine sediments. A comparison of black carbon based on thermal oxidation and hot concentrated nitric acid pretreatments revealed that the latter significantly overestimates combustion derived carbon phases. Black carbon accounts for abo

  9. Warped products and black holes

    International Nuclear Information System (INIS)

    We apply the warped product space-time scheme to the Banados-Teitelboim-Zanelli black holes and the Reissner-Nordstroem-anti-de Sitter black hole to investigate their interior solutions in terms of warped products. It is shown that there exist no discontinuities of the Ricci and Einstein curvatures across event horizons of these black holes

  10. Black Progress: Convergence or Cleavage?

    Science.gov (United States)

    Hill, Robert B.

    1982-01-01

    The popular view of a permanent Black underclass falling farther behind an expanding Black middle class is disputed by empirical evidence that the underclass is experiencing upward mobility. The discrepancy stems from social scientists' overreliance on cross-sectional data rather than longitudinal data in analyzing economic change among Blacks.…

  11. Warped products and black holes

    CERN Document Server

    Hong, S T

    2005-01-01

    We apply the warped product spacetime scheme to the Banados-Teitelboim-Zanelli black holes and the Reissner-Nordstr\\"om-anti-de Sitter black hole to investigate their interior solutions in terms of warped products. It is shown that there exist no discontinuities of the Ricci and Einstein curvatures across event horizons of these black holes.

  12. Black silicon with black bus-bar strings

    DEFF Research Database (Denmark)

    Davidsen, Rasmus Schmidt; Tang, Peter Torben; Mizushima, Io;

    2016-01-01

    We present the combination of black silicon texturing and blackened bus-bar strings as a potential method for obtaining all-black solar panels, while using conventional, front-contacted solar cells. Black silicon was realized by mask-less reactive ion etching resulting in total, average reflectance...... below 0.5% across a 156x156 mm2 silicon wafer. Black bus-bars were realized by oxidized copper resulting in reflectance below 3% in the entire visible wavelength range. The combination of these two technologies may result in aesthetic, all-black panels based on conventional, front-contacted solar cells...

  13. Synthesis and Characterization of Nickel-Alumina Composites from Recycled Nickel Powder

    Directory of Open Access Journals (Sweden)

    V. G. Karayannis

    2012-01-01

    Full Text Available The recycling of metallic waste to create more valuable materials and their valorization into upgraded metal-based composites constitutes an important field of study. The composite industry nowadays considers environmental improvements as important as other properties of the materials. In the present paper, nickel powder was recycled from ferrous scrap, a low-cost and largely available material, by an effective hydrometallurgical recovery process. Then, this recycled powder was successfully used along with particulate α-alumina to prepare oblong nickel-based composite specimens with ceramic reinforcement loadings ranging from 0 to 30 wt.% by applying powder processing manufacturing techniques including cold isostatic pressing (CIP and sintering. The microstructures obtained were characterized, the specimens were subjected to three-point bend tests, and their fracture behaviour was evaluated. By increasing the % ceramic reinforcement content, density clearly decreases while strengthening is achieved, thus leading to development of lightweight and enhanced oblong nickel-alumina composites. The composite microstructure, and particularly the metal-ceramic interface bonding, has a strong impact on fracture behaviour upon external loading.

  14. Nickel-Catalyzed Aromatic C-H Functionalization.

    Science.gov (United States)

    Yamaguchi, Junichiro; Muto, Kei; Itami, Kenichiro

    2016-08-01

    Catalytic C-H functionalization using transition metals has received significant interest from organic chemists because it provides a new strategy to construct carbon-carbon bonds and carbon-heteroatom bonds in highly functionalized, complex molecules without pre-functionalization. Recently, inexpensive catalysts based on transition metals such as copper, iron, cobalt, and nickel have seen more use in the laboratory. This review describes recent progress in nickel-catalyzed aromatic C-H functionalization reactions classified by reaction types and reaction partners. Furthermore, some reaction mechanisms are described and cutting-edge syntheses of natural products and pharmaceuticals using nickel-catalyzed aromatic C-H functionalization are presented. PMID:27573407

  15. Dynamic corrosion of copper-nickel sulfide by Acidithiobacillus ferrooxidans

    Institute of Scientific and Technical Information of China (English)

    TONG Lin-lin; JIANG Mao-fa; YANG Hong-ying; YU Juan; FAN You-jing; ZHANG Yao

    2009-01-01

    The dynamic corrosion process of bio-oxidation of copper-nickel sulfide from Karatungk in northern Xinjiang Province of China was studied. The polished wafer of the copper-nickel sulphide was used to carry on a series of oxidation corrosion experiment by Acidithiobacillus ferrooxidans. The changes of superficial corrosion appearance and the mineral dynamic corrosion process were discovered by microscope observation. Then, the galvanic cell model was established, and the bio-oxidation activation order of typical copper-nickel sulphide minerals was ascertained as pyrrhotite>pentlandite>chalocopyrite.

  16. REPORT FOR COMMERCIAL GRADE NICKEL CHARACTERIZATION AND BENCHMARKING

    Energy Technology Data Exchange (ETDEWEB)

    None

    2012-12-20

    Oak Ridge Associated Universities (ORAU), under the Oak Ridge Institute for Science and Education (ORISE) contract, has completed the collection, sample analysis, and review of analytical results to benchmark the concentrations of gross alpha-emitting radionuclides, gross beta-emitting radionuclides, and technetium-99 in commercial grade nickel. This report presents methods, change management, observations, and statistical analysis of materials procured from sellers representing nine countries on four continents. The data suggest there is a low probability of detecting alpha- and beta-emitting radionuclides in commercial nickel. Technetium-99 was not detected in any samples, thus suggesting it is not present in commercial nickel.

  17. High Prevalence of Nickel Allergy in an Overweight Female Population: A Pilot Observational Analysis

    OpenAIRE

    Lusi, Elena Angela; Di Ciommo, Vincenzo Maria; Patrissi, Tommaso; Guarascio, Paolo

    2015-01-01

    Context In our Allergy Unit, we incidentally observed that a low Nickel diet, prescribed for delayed allergy to Nickel sulfate, reduced body mass index (BMI) and waist circumference in overweight patients. Objectives This pilot cross-sectional analysis was undertaken to compare the prevalence of Nickel allergy of overweight individuals versus the general population. We also had the chance to report the efficacy of a low Nickel diet on BMI and waist circumference in Nickel-sensitive overweight...

  18. Dictionary of Black Culture.

    Science.gov (United States)

    Baskin, Wade; Runes, Richard N.

    This dictionary is an encyclopedic survey of the cultural background and development of the black American, covering the basic issues, events, contributions and biographies germane to the subject. The author-compiler is Chairman of Classical Languages Department at Southeastern State College, Durant, Oklahoma. Richard Runes is practicing law as a…

  19. Black History Speech

    Science.gov (United States)

    Noldon, Carl

    2007-01-01

    The author argues in this speech that one cannot expect students in the school system to know and understand the genius of Black history if the curriculum is Eurocentric, which is a residue of racism. He states that his comments are designed for the enlightenment of those who suffer from a school system that "hypocritically manipulates Black…

  20. Newborn Black Holes

    Science.gov (United States)

    Science Teacher, 2005

    2005-01-01

    Scientists using NASA's Swift satellite say they have found newborn black holes, just seconds old, in a confused state of existence. The holes are consuming material falling into them while somehow propelling other material away at great speeds. "First comes a blast of gamma rays followed by intense pulses of x-rays. The energies involved are much…

  1. Gasification of black liquor

    Science.gov (United States)

    Kohl, Arthur L.

    1987-07-28

    A concentrated aqueous black liquor containing carbonaceous material and alkali metal sulfur compounds is treated in a gasifier vessel containing a relatively shallow molten salt pool at its bottom to form a combustible gas and a sulfide-rich melt. The gasifier vessel, which is preferably pressurized, has a black liquor drying zone at its upper part, a black liquor solids gasification zone located below the drying zone, and a molten salt sulfur reduction zone which comprises the molten salt pool. A first portion of an oxygen-containing gas is introduced into the gas space in the gasification zone immediatley above the molten salt pool. The remainder of the oxygen-containing gas is introduced into the molten salt pool in an amount sufficient to cause gasification of carbonaceous material entering the pool from the gasification zone but not sufficient to create oxidizing conditions in the pool. The total amount of the oxygen-containing gas introduced both above the pool and into the pool constitutes between 25 and 55% of the amount required for complete combustion of the black liquor feed. A combustible gas is withdrawn from an upper portion of the drying zone, and a melt in which the sulfur content is predominantly in the form of alkali metal sulfide is withdrawn from the molten salt sulfur reduction zone.

  2. Trichomicosis pubis: black variety.

    OpenAIRE

    Neri, I.; Frassetto, A; Pasquinelli, G.; Patrizi, A.

    1994-01-01

    A case of a 25 year old man with the black variety of trichomicosis pubis is presented on account of its extreme rareity. Scanning electron microscopy confirms that trichomicosis pubis is caused by bacterial colonisation of the pubic hair and shows that bacteria are able to penetrate cuticular horny cells directly through their free plasma membrane.

  3. Black hole magnetospheres

    International Nuclear Information System (INIS)

    We investigate the structure of the steady-state force-free magnetosphere around a Kerr black hole in various astrophysical settings. The solution Ψ(r, θ) depends on the distributions of the magnetic field line angular velocity ω(Ψ) and the poloidal electric current I(Ψ). These are obtained self-consistently as eigenfunctions that allow the solution to smoothly cross the two singular surfaces of the problem, the inner light surface inside the ergosphere, and the outer light surface, which is the generalization of the pulsar light cylinder. Magnetic field configurations that cross both singular surfaces (e.g., monopole, paraboloidal) are uniquely determined. Configurations that cross only one light surface (e.g., the artificial case of a rotating black hole embedded in a vertical magnetic field) are degenerate. We show that, similar to pulsars, black hole magnetospheres naturally develop an electric current sheet that potentially plays a very important role in the dissipation of black hole rotational energy and in the emission of high-energy radiation.

  4. When Black Holes Collide

    Science.gov (United States)

    Baker, John

    2010-01-01

    Among the fascinating phenomena predicted by General Relativity, Einstein's theory of gravity, black holes and gravitational waves, are particularly important in astronomy. Though once viewed as a mathematical oddity, black holes are now recognized as the central engines of many of astronomy's most energetic cataclysms. Gravitational waves, though weakly interacting with ordinary matter, may be observed with new gravitational wave telescopes, opening a new window to the universe. These observations promise a direct view of the strong gravitational dynamics involving dense, often dark objects, such as black holes. The most powerful of these events may be merger of two colliding black holes. Though dark, these mergers may briefly release more energy that all the stars in the visible universe, in gravitational waves. General relativity makes precise predictions for the gravitational-wave signatures of these events, predictions which we can now calculate with the aid of supercomputer simulations. These results provide a foundation for interpreting expect observations in the emerging field of gravitational wave astronomy.

  5. The Black Plateau.

    Science.gov (United States)

    Rouse, Donald E.

    This study describes and assesses the basic problems of black males who enter educational administration as a career, showing the relationship between their cultural background and their aspirations in the field of administration of a large city school system. The role taken by the researcher is that of participant-observer. The collection of…

  6. Controlled synthesis of size-tunable nickel and nickel oxide nanoparticles using water-in-oil microemulsions

    Science.gov (United States)

    Kumar, Ajeet; Saxena, Amit; De, Arnab; Shankar, Ravi; Mozumdar, Subho

    2013-06-01

    Industrial demands have generated a growing need to synthesize pure metal and metal-oxide nanoparticles of a desired size. We report a novel and convenient method for the synthesis of spherical, size tunable, well dispersed, stable nickel and nickel oxide nanoparticles by reduction of nickel nitrate at room temperature in a TX-100/n-hexanol/cyclohexane/water system by a reverse microemulsion route. We determined that reduction with alkaline sodium borohydrate in nitrogen atmosphere leads to the formation of nickel nanoparticles, while the use of hydrazine hydrate in aerobic conditions leads to the formation of nickel oxide nanoparticles. The influence of several reaction parameters on the size of nickel and nickel oxide nanoparticles were evaluated in detail. It was found that the size can be easily controlled either by changing the molar ratio of water to surfactant or by simply altering the concentration of the reducing agent. The morphology and structure of the nanoparticles were characterized by quasi-elastic light scattering (QELS), transmission electron microscopy (TEM), x-ray diffraction (XRD), electron diffraction analysis (EDA) and energy dispersive x-ray (EDX) spectroscopy. The results show that synthesized nanoparticles are of high purity and have an average size distribution of 5-100 nm. The nanoparticles prepared by our simple methodology have been successfully used for catalyzing various chemical reactions.

  7. Toxicogenomic effect of nickel and beyond.

    Science.gov (United States)

    Yao, Yixin; Costa, Max

    2014-09-01

    Nickel is widely applied in industrial settings and Ni(II) compounds have been classified as group one human carcinogens. The molecular basis of Ni(II) carcinogenicity has proved complex, for many stress response pathways are activated and yield unexpected Ni(II)-specific toxicology profile. Ni(II)-induced toxicogenomic change has been associated with altered activity of HIF, p53, c-MYC, NFκB and iron and 2-oxoglutarate-dependent dioxygenases. Advancing high-throughput technology has indicated the toxicogenome of Ni(II) involves crosstalk between HIF, p53, c-MYC, NFκB and dioxygenases. This paper is intended to review the network of Ni(II)-induced common transcription-factor-governed pathways by discussing transcriptome alteration, its governing transcription factors and the underlying mechanism. Finally, we propose a putative target network of Ni(II) as a human carcinogen. PMID:25069803

  8. Electroless nickel plating on optical fiber probe

    Institute of Scientific and Technical Information of China (English)

    Li Huang; Zhoufeng Wang; Zhuomin Li; Wenli Deng

    2009-01-01

    As a component of near-field scanning optical microscope (NSOM),optical fiber probe is an important factor influncing the equipment resolution.Electroless nickel plating is introduced to metallize the optical fiber probe.The optical fibers are etched by 40% HF with Turner etching method.Through pretreatment,the optical fiber probe is coated with Ni-P film by clectrolcss plating in a constant temperature water tank.Atomic absorption spectrometry (AAS),scanning electron microscopy (SEM),and energy dispersive X-ray spectrometry (EDXS) are carried out to charaeterizc the deposition on fiber probe.We have rcproducibly fabricated two kinds of fiber probes with a Ni-P fihn:aperture probe and apertureless probe.In addition,reductive particle transportation on the surface of fiber probe is proposed to explain the cause of these probes.

  9. Hydrogen Embrittlement of Pulse-Plated Nickel

    Science.gov (United States)

    Reese, Eggert D.; Von Bestenbostel, Wolfgang; Sebald, Torsten; Paronis, Georgios; Vanelli, Diego; Müller, Yves

    2014-08-01

    The objective of the European-funded project MultiHy (Multiscale modeling of hydrogen embrittlement in crystalline materials) is the development of multiscale models for hydrogen transport in complex microstructures. The validation and application of the models will be carried out by investigating the role of the microstructure in industrial problems involving hydrogen embrittlement (HE) of advanced materials. Pulse-plated nickel (PP-Ni) material, as used in various industrial applications, has shown a susceptibility to HE that may cause premature failure of a structure. Due to the nature of the pulse-plating process, H is incorporated into the microstructure of the material. This H may lead to crack initiation when combined with localized stress concentrations due to subsequent manufacturing steps, e.g., welding. This article provides an overview of experimental studies aimed at evaluating the influence of the microstructure on the susceptibility of PP-Ni to HE and, ultimately, at improving the plating process.

  10. Nickel-48, a very magic nucleus

    International Nuclear Information System (INIS)

    Ni48, which is doubly magic and very exotic, has been observed in an experiment performed at the GANIL accelerator. This nucleus, which is composed of 20 neutrons and 28 protons, is the most neutron-deficient nucleus that can be obtained, its decay mode has not yet been determined but theory predicts a 2-proton emission. Ni48 nuclei were obtained when accelerated (75 MeV/A) Ni58 ions had undergone fragmentation on natural nickel target. During this experiment 4 nuclei of Ni48 were produced as well as other very exotic nuclei: 90 nuclei of Ni49, 50 of Fe45 and 290 of Cr42. This experiment lasted 10 days and 1017 Ni58 ions were projected on the target. (A.C.)

  11. Nickel-63 in Baltic fish and sediments

    International Nuclear Information System (INIS)

    The determination of 63Ni was carried out on fish samples of cod (Gadus morhua), herring (Clupea harengus), sprat (Sprattus sprattus) and samples of sediment core from the Gdansk Bay. In contrast to stable nickel, 63Ni is non-uniformly distributed within the fish. More than 95% of total 63Ni content in cod and herring is located in fillet with skin and scale. Our data suggests, that mechanism for uptake of 63Ni in cod and herring is by passive adsorption onto the surface of skin and scale mucus. The concentration of 63Ni in analysed sediment lies within the range from 0.5 to 3.8 mBq·g-1 dry wt, while values of its specific activity ranged between 10 and 70 Bq·g-1. (Author)

  12. Nickel-induced crystallization of amorphous silicon

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, J A; Arce, R D; Buitrago, R H [INTEC (CONICET-UNL), Gueemes 3450, S3000GLN Santa Fe (Argentina); Budini, N; Rinaldi, P, E-mail: jschmidt@intec.unl.edu.a [FIQ - UNL, Santiago del Estero 2829, S3000AOM Santa Fe (Argentina)

    2009-05-01

    The nickel-induced crystallization of hydrogenated amorphous silicon (a-Si:H) is used to obtain large grained polycrystalline silicon thin films on glass substrates. a-Si:H is deposited by plasma enhanced chemical vapour deposition at 200 deg. C, preparing intrinsic and slightly p-doped samples. Each sample was divided in several pieces, over which increasing Ni concentrations were sputtered. Two crystallization methods are compared, conventional furnace annealing (CFA) and rapid thermal annealing (RTA). The crystallization was followed by optical microscopy and scanning electron microscopy observations, X-ray diffraction, and reflectance measurements in the UV region. The large grain sizes obtained - larger than 100{mu}m for the samples crystallized by CFA - are very encouraging for the preparation of low-cost thin film polycrystalline silicon solar cells.

  13. The search for superconductivity in rare earth nickel(iii) and nickel (i) oxides

    International Nuclear Information System (INIS)

    We have undertaken a systematic study of the Ln2xSrxNiO4-δ system over the entire lanthanide range, focusing on doping levels above x 1.0. It was observed that for samples prepared under flowing O2 at 1100 deg C, the upper solid solution limit was x = 1.67. The lower solubility limit increased with decreasing ionic radii for Ln = Nd3+ - Gd3+, forming essentially point phases Ln033Sr1.67NiO3.67 (LnSr5Ni3O11) for Ln = Y3+, Dy3+ - Tm3+. Thermo- gravimetric analysis of these phases indicated that they contained nickel in a 3+ oxidation state. Rietveld refinement of the structure of these materials using powder X-ray diffraction data showed that each adopted the tetragonal K2NiF4 structure(I4/mmm), with Ln3+ and Sr2+ disordered over the K sites and oxygen vacancies occuring predominantly in the NiO2 planes. Electrical conductivity measurements of YSr5Ni3O11 indicate semiconducting behaviour which is able to be modelled by variable range hopping. Magnetic susceptibility measurements between 6 K and 300 K show Curie-Weiss behaviour, with substantially lower effective moments than expected from spin only low-spin Ni(III) due to the delocalisation of the nickel electrons. Partial thermogravimetric reduction of LnSr5Ni3O11 (Ln = Y, Dy - Tm) led to a series of nickel(I) oxides: LnSr5Ni3O8. Rietveld refinement of the structure of these materials using powder X-ray diffraction data indicated a transition from a tetragonal K2NiF4 to an orthorhombic Sr2CuO3 (Immm) arrangement, in which l/3 of the bridging oxygen atoms were missing from the chains of apex-linked nickel oxide square planes. Bond valence calculations supported the notion of nickel being present as Ni+

  14. Observational Evidence for Black Holes

    OpenAIRE

    Narayan, Ramesh; McClintock, Jeffrey E.

    2013-01-01

    Astronomers have discovered two populations of black holes: (i) stellar-mass black holes with masses in the range 5 to 30 solar masses, millions of which are present in each galaxy in the universe, and (ii) supermassive black holes with masses in the range 10^6 to 10^{10} solar masses, one each in the nucleus of every galaxy. There is strong circumstantial evidence that all these objects are true black holes with event horizons. The measured masses of supermassive black hole are strongly corr...

  15. Over spinning a black hole?

    Energy Technology Data Exchange (ETDEWEB)

    Bouhmadi-Lopez, Mariam; Cardoso, Vitor; Nerozzi, Andrea; Rocha, Jorge V, E-mail: mariam.bouhmadi@ist.utl.pt, E-mail: vitor.cardoso@ist.utl.pt, E-mail: andrea.nerozzi@ist.utl.pt, E-mail: jorge.v.rocha@ist.utl.pt [CENTRA, Department de Fisica, Instituto Superior Tecnico, Av. Rovisco Pais 1, 1049 Lisboa (Portugal)

    2011-09-22

    A possible process to destroy a black hole consists on throwing point particles with sufficiently large angular momentum into the black hole. In the case of Kerr black holes, it was shown by Wald that particles with dangerously large angular momentum are simply not captured by the hole, and thus the event horizon is not destroyed. Here we reconsider this gedanken experiment for black holes in higher dimensions. We show that this particular way of destroying a black hole does not succeed and that Cosmic Censorship is preserved.

  16. Statistical mechanics of black holes

    International Nuclear Information System (INIS)

    We analyze the statistical mechanics of a gas of neutral and charged black holes. The microcanonical ensemble is the only possible approach to this system, and the equilibrium configuration is the one for which most of the energy is carried by a single black hole. Schwarzschild black holes are found to obey the statistical bootstrap condition. In all cases, the microcanonical temperature is identical to the Hawking temperature of the most massive black hole in the gas. U(1) charges in general break the bootstrap property. The problems of black-hole decay and of quantum coherence are also addressed

  17. BlackBerry For Dummies

    CERN Document Server

    Kao, Robert

    2010-01-01

    Get the most juice out of your BlackBerry handheld!. Feature-rich and complex, the BlackBerry is the number one smartphone in the corporate world is among the most popular handhelds for business users. This new and updated edition includes all the latest and greatest information on new and current BlackBerry mobile devices. Covering a range of valuable how-to topics, this helpful guide explores the BlackBerry's most useful features, techniques for getting the most out of your BlackBerry, and practical information about power usage.: Covers all aspects of the number one smartphone in the corpor

  18. Prisons of light : black holes

    Science.gov (United States)

    Ferguson, Kitty

    What is a black hole? Could we survive a visit to one -- perhaps even venture inside? Have we yet discovered any real black holes? And what do black holes teach us about the mysteries of our Universe? These are just a few of the tantalizing questions examined in this tour-de-force, jargon-free review of one of the most fascinating topics in modern science. In search of the answers, we trace a star from its birth to its death throes, take a hypothetical journey to the border of a black hole and beyond, spend time with some of the world's leading theoretical physicists and astronomers, and take a whimsical look at some of the wild ideas black holes have inspired. Prisons of Light - Black Holes is comprehensive and detailed. Yet Kitty Ferguson's lightness of touch and down-to-earth analogies set this book apart from all others on black holes and make it a wonderfully stimulating and entertaining read.

  19. Point mass Cosmological Black Holes

    CERN Document Server

    Firouzjaee, Javad T

    2016-01-01

    Real black holes in the universe are located in the expanding accelerating background which are called the cosmological black holes. Hence, it is necessary to model these black holes in the cosmological background where the dark energy is the dominant energy. In this paper, we argue that most of the dynamical cosmological black holes can be modeled by point mass cosmological black holes. Considering the de Sitter background for the accelerating universe, we present the point mass cosmological background in the cosmological de Sitter space time. Our work also includes the point mass black holes which have charge and angular momentum. We study the mass, horizons, redshift structure and geodesics properties for these black holes.

  20. Nickel Chloride Promoted Glaser Coupling Reaction in Hot Water

    Institute of Scientific and Technical Information of China (English)

    Pin Hua LI; Lei WANG; Min WANG; Jin Can YAN

    2004-01-01

    A Glaser coupling reaction of terminal alkynes in the presence of nickel chloride without any organics and bases in hot water has been developed, which produces the corresponding homo-coupling products in good yields.

  1. Nickel plating of spent fuel element transportation and storage containers

    International Nuclear Information System (INIS)

    For economic reasons, the stainless steel used for nuclear transport and storage containers has been replaced by a significantly less expensive, but almost equally suitable material - spheroidal graphite cast iron. Because of the impossibility of sufficiently decontaminating raw cast iron surfaces, a suitable coating had to be developed. Steel lining, epoxy painting and soft nickel plating are known possibilities. If both the requirements made on such a coating and the economics are considered, soft nickel seems to be the most attractive solution. The paper describes the process of soft nickel plating which was developed by Von Roll, Switzerland, based on its proprietary ''Toraxier-Process'' - in co-operation with GNS (Gesellschaft fuer Nuklear-Service mbH, Essen). Soft nickel plating has been successfully applied to more than 30 Castor containers. (author)

  2. Radio-absorbing properties of nickel-containing schungite powder

    Science.gov (United States)

    Lyn'kov, L. M.; Borbot'ko, T. V.; Krishtopova, E. A.

    2009-05-01

    A nickel-containing shungite powder has been synthesized by means of chemical reduction from aqueous solutions. The chemical composition and radio-absorbing properties of this powder have been studied.

  3. Spectroscopic and thermogravimetric study of nickel sulfaquinoxaline complex

    Science.gov (United States)

    Tailor, Sanjay M.; Patel, Urmila H.

    2016-05-01

    The ability of sulfaquinoxaline (4-Amino-N-2-quinoxalinylbenzenesulfonamide) to form metal complexes are investigated. The nickel complex of sulfaquinoxaline is prepared by reflux method and characterized by CHN analysis and IR spectra. The results of IR spectral data suggest that the binding of nickel atom to the sulfonamidic nitrogen are in good agreement. The thermogravimetric analysis (TGA), differential thermal analysis (DTA) and differential thermogravimetric (DTG) analysis of nickel sulfaquinoxaline are carried out from ambient temperature to 750°C in inert nitrogen atmosphere. The activation energy, enthalpy, entropy and Gibbs free energy of nickel sulfaquinoxaline complex is determined from the thermal curves using Broido method. The results are reported in this paper.

  4. Copper and nickel adherently electroplated on titanium alloy

    Science.gov (United States)

    Brown, E. E.

    1967-01-01

    Anodic treatment of titanium alloy enables electroplating of tightly adherent coatings of copper and nickel on the alloy. The alloy is treated in a solution of hydrofluoric and acetic acids, followed by the electroplating process.

  5. Response of nickel surface to pulsed fusion plasma radiations

    Energy Technology Data Exchange (ETDEWEB)

    Niranjan, Ram, E-mail: niranjan@barc.gov.in; Rout, R. K., E-mail: niranjan@barc.gov.in; Srivastava, R., E-mail: niranjan@barc.gov.in; Gupta, Satish C. [Applied Physics Division, Bhabha Atomic Research Centre, Mumbai-400085 (India); Chakravarthy, Y. [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai-400085 (India); Patel, N. N. [High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Mumbai-400085 (India); Alex, P. [Materials Processing Division, Bhabha Atomic Research Centre, Mumbai-400085 (India)

    2014-04-24

    Nickel based alloys are being projected as suitable materials for some components of the next generation fusion reactor because of compatible thermal, electrical and mechanical properties. Pure nickel material is tested here for possibility of similar application purpose. Nickel samples (> 99.5 % purity) are exposed here to plasma radiations produced due to D-D fusion reaction inside an 11.5 kJ plasma focus device. The changes in the physical properties of the nickel surface at microscopic level which in turn change the mechanical properties are analyzed using scanning electron microscope, optical microscope, glancing incident X-ray diffractometer and Vicker's hardness gauge. The results are reported here.

  6. On the rational alloying of structural chromium-nickel steels

    International Nuclear Information System (INIS)

    A study was made on the influence of chromium nickel, phosphorus on the critical brittleness temperature of Cr-Ni-Mo-V structural steels. It is shown that the critical brittleness temperature of these steels increases at chromium content more over than 2% and nickel content more than 2% in the result of carbide transformations during tempering. Increase of nickel content in Cr-Ni-Mo-V-steels strengthens the tendency to embrittlement during slow cooling, from tempering temperature owing to development of process of phosphorus grain-boundary segregation. Two mentioned mechanisms of embrittlement determine principles of rational steel alloying. The extreme dependence of the critical brittleness temperature on chromium and nickel content, which enables to choose the optimum composition of Cr-Ni-Mo-V-steels, was established

  7. Reference values for the nickel concentration in human finger nails

    DEFF Research Database (Denmark)

    Gammelgaard, Bente; Peters, K; Menné, T

    1991-01-01

    A reference value for the nickel concentration in finger nails from people who are not occupationally exposed to nickel was determined on the basis of nail samples from 95 healthy individuals. The mean +/- standard deviation was 1.19 +/- 1.61 mg/kg and the median was 0.49 mg/kg (range 0.042-7.50 mg....../kg). The 95% confidence interval of the population mean was 0.51-1.26 mg/kg and the 95% confidence interval of the population median was 0.39-0.74 mg/kg. The random sample consisted of 59 women and 36 men. No significant difference between the nickel levels in finger nails from men and women could...... be demonstrated. The age of the subjects varied from 16 to 66 years. There was no correlation between age and nickel concentration in finger nails....

  8. In-situ scanning probe microscopy of electrodeposited nickel.

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, James J.; Dibble, Dean C.

    2004-10-01

    The performance characteristics and material properties such as stress, microstructure, and composition of nickel coatings and electroformed components can be controlled over a wide range by the addition of small amounts of surface-active compounds to the electroplating bath. Saccharin is one compound that is widely utilized for its ability to reduce tensile stress and refine grain size in electrodeposited nickel. While the effects of saccharin on nickel electrodeposition have been studied by many authors in the past, there is still uncertainty over saccharin's mechanisms of incorporation, stress reduction, and grain refinement. In-situ scanning probe microscopy (SPM) is a tool that can be used to directly image the nucleation and growth of thin nickel films at nanometer length scales to help elucidate saccharin's role in the development and evolution of grain structure. In this study, in-situ atomic force microscopy (AFM) and scanning tunneling microscopy (STM) techniques are used to investigate the effects of saccharin on the morphological evolution of thin nickel films. By observing mono-atomic height nickel island growth with and without saccharin present we conclude that saccharin has little effect on the nickel surface mobility during deposition at low overpotentials where the growth occurs in a layer-by-layer mode. Saccharin was imaged on Au(l11) terraces as condensed patches without resolved packing structure. AFM measurements of the roughness evolution of nickel films up to 1200 nm thick on polycrystalline gold indicate that saccharin initially increases the roughness and surface skewness of the deposit that at greater thickness becomes smoother than films deposited without saccharin. Faceting of the deposit morphology decreases as saccharin concentration increases even for the thinnest films that have 3-D growth.

  9. Stainless Steel Leaches Nickel and Chromium into Foods During Cooking

    OpenAIRE

    Kamerud, Kristin L.; Hobbie, Kevin A.; Anderson, Kim A.

    2013-01-01

    Toxicological studies show that oral doses of nickel and chromium can cause cutaneous adverse reactions such as dermatitis. Additional dietary sources, such as leaching from stainless steel cookware during food preparation, are not well characterized. This study examined stainless steel grades, cooking time, repetitive cooking cycles, and multiple types of tomato sauces for their effects on nickel and chromium leaching. Trials included three types of stainless steels and a stainless steel sau...

  10. Sintered Nickel Powder Wicks for Flat Vertical Heat Pipes

    OpenAIRE

    Geir Hansen; Erling Næss; Kolbeinn Kristjansson

    2015-01-01

    The fabrication and performance of wicks for flat heat pipe applications produced by sintering a filamentary nickel powder has been investigated. Tape casting was used as an intermediate step in the wick production process. Thermogravimetric analysis was used to study the burn-off of the organic binder used and to study the oxidation and reduction processes of the nickel. The wicks produced were flat, rectangular and intended for liquid transport in the upwards vertical direction. Rate-of-ris...

  11. Accounting for the Dynamic Oxidative Behavior of Nickel Anodes.

    Science.gov (United States)

    Smith, Rodney D L; Berlinguette, Curtis P

    2016-02-10

    The dynamic behavior of the anodic peak for amorphous nickel oxy/hydroxide (a-NiOx) films in basic media was investigated. Chronocoulometry of films with known nickel concentrations reveals that a total of four electrons per nickel site comprise the signature anodic peak at 1.32 V during the first oxidative scan, and two electrons are passed through the associated cathodic peak on the reverse scan. The anodic and cathodic signals each contain two electrons on the successive scans. Catalytic oxygen evolution reaction (OER) was detected within the anodic peak, which is at a lower potential than is widely assumed. In order to rationalize these experimental results, we propose that the four-electron oxidation event is the conversion of the film from nickel(II) hydroxide ([Ni(II)-OH](-)) to a higher valent nickel peroxide species (e.g., Ni(IV)-OO or Ni(III)-OO·). The subsequent reduction of the nickel peroxide species is confined by a chemical step resulting in the accumulation of [Ni(II)-OOH](-), which is then oxidized by two electrons to form Ni(IV)-OO during the subsequent oxidative scan on the time scale of a cyclic voltammetric experiment. Our proposed mechanism and the experimental determination that each nickel site is oxidized by four electrons helps link the myriad of seemingly disparate literature data related to OER catalysis by nickel electrodes. The faster catalysis that occurs at higher oxidative potentials is derived from a minority species and is not elaborated here. PMID:26829375

  12. Synthesis, structure characterization and catalytic activity of nickel tungstate nanoparticles

    International Nuclear Information System (INIS)

    Graphical abstract: NiWO4 nanoparticles were prepared via precipitation technique. Experimental parameters of procedure were optimized statistically. Highlights: ► NiWO4 spherical nanoparticles were synthesized via direct precipitation method. ► Taguchi robust design was used for optimization of synthesis reaction parameters. ► Composition and structural properties of NiWO4 nanoparticles were characterized. ► EDAX, XRD, SEM, FT-IR, UV–vis and photoluminescence techniques were employed. ► Catalytic activity of the product in a cyclo-addition reaction was investigated. - Abstract: Taguchi robust design was applied to optimize experimental parameters for controllable, simple and fast synthesis of nickel tungstate nanoparticles. NiWO4 nanoparticles were synthesized by precipitation reaction involving addition of nickel ion solution to the tungstate aqueous reagent and then formation of nickel tungstate nucleolus which are insoluble in aqueous media. Effects of various parameters such as nickel and tungstate concentrations, flow rate of reagent addition and reactor temperature on diameter of synthesized nickel tungstate nanoparticles were investigated experimentally by the aid of orthogonal array design. The results for analysis of variance (ANOVA) showed that particle size of nickel tungstate can be effectively tuned by controlling significant variables involving nickel and tungstate concentrations and flow rate; while, temperature of the reactor has a no considerable effect on the size of NiWO4 particles. The ANOVA results proposed the optimum conditions for synthesis of nickel tungstate nanoparticles via this technique. Also, under optimum condition nanoparticles of NiWO4 were prepared and their structure and chemical composition were characterized by means of EDAX, XRD, SEM, FT-IR spectroscopy, UV–vis spectroscopy, and photoluminescence. Finally, catalytic activity of the nanoparticles in a cycloaddition reaction was examined.

  13. Metamagnetism and Weak Ferromagnetism in Nickel (II) oxalate crystals

    OpenAIRE

    Romero, E.; Mendoza, ME; Escudero, R.

    2012-01-01

    Microcrystals of orthorhombic nickel (II) oxalate dihydrate were synthesized through a precipitation reaction of aqueous solutions of nickel chloride and oxalic acid. Magnetic susceptibility exhibits a sharp peak at 3.3 K and a broadrounded maximum near 43 K. We associated the lower maximum with a metamagnetic transition that occurs when the magnetic field is about \\geq 3.5 T. The maximum at 43 K is the typical of 1D antiferromagnets, whereas weak ferromagnetism behavior was observed in the r...

  14. Copper-nickel alloys for marine aquacultural engineering

    OpenAIRE

    Ravindran, K

    1983-01-01

    Engineering developments, problems of marine corrosion, fouling and practical innovative applications of copper-nickel alloys in comparison with other materials for marine aquacultural engineering are presented. Coefficient of drag and hydrodynamic force acting on nylon and polyethylene net enclosures have shown a four-fold increase of force in four months at the Cochin harbour due to fouling. Corrosion behaviour of copper-nickel and other copper base alloys are also presented. Effects of cop...

  15. Properties Of Electrochromic Nickel Oxide Coatings Produced By Reactive Evaporation

    Science.gov (United States)

    Bange, Klaus; Baucke, Friedrich G.; Metz, Bernard

    1989-03-01

    Single films of nickel oxide deposited by reactive evaporation and all-solid-state devices (ASSDs) containing such films have been investigated. The as-deposited nickel oxide films were analysed by standard surface and thin film-sensitive methods (AES, ESCA, RBS, NRA), and the findings were correlated with deposition parameters. The electrochromism of single layers was characterized by cyclic voltammetry and photospectrometry and compared with optical and electrical data of electrochromic all-solid-state devices.

  16. Properties of electrochromic nickel oxide coatings produced by reactive evaporation

    International Nuclear Information System (INIS)

    Single films of nickel oxide deposited by reactive evaporation and all-solid-state devices (ASSDs) containing such films have been investigated. The as-deposited nickel oxide films were analysed by standard surface and thin film-sensitive methods (AES, ESCA, RBS, NRA), and the findings were correlated with deposition parameters. The electrochromism of single layers was characterized by cyclic voltammetry and photospectrometry and compared with optical and electrical data of electrochromic all-solid-state devices

  17. Nickel matrix micro/nano SiC composite electrodeposition

    OpenAIRE

    Albert Calbeto, Sònia

    2010-01-01

    Electrochemical codeposition is widely used in the last decade to produce composite metal matrix coatings. Hard particles such as oxides or carbides embedded in a metal matrix coating aim to increase its mechanical and wear properties. The use of nanometric particles could also change the microstructure of the electrodeposits leading to a more compact structure and thus to an increased corrosion resistance. The aim of this work is the production of pure nickel, nickel containing SiC micro-...

  18. Advances in nickel hydrogen technology at Yardney Battery Division

    Science.gov (United States)

    Bentley, J. G.; Hall, A. M.

    1987-01-01

    The current major activites in nickel hydrogen technology being addressed at Yardney Battery Division are outlined. Five basic topics are covered: an update on life cycle testing of ManTech 50 AH NiH2 cells in the LEO regime; an overview of the Air Force/industry briefing; nickel electrode process upgrading; 4.5 inch cell development; and bipolar NiH2 battery development.

  19. Structure and composition of admixture precipitates of nickel in silicon

    International Nuclear Information System (INIS)

    Structure and composition of precipitates of nickel atoms in monocrystalline silicon were investigated by electron-probe microanalysis. precipitates were found to consist of silicides of nickel involving some technological impurities and have needle, disk and ball forms, which can disintegrate under influence of external pressures. Because of distinct environmental conditions around precipitates of various forms their disintegration also differs from each other and it leads to corresponding alteration of crystals electrophysical parameter. (author)

  20. Analysis of polyaniline-based nickel electrodes for electrochemical supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Girija, T.C.; Sangaranarayanan, M.V. [Department of Chemistry, Indian Institute of Technology, Chennai 600 036 (India)

    2006-06-01

    Polyaniline is deposited potentiodynamically on a nickel substrate in the presence of p-toluene sulfonic acid and the specific capacitance is estimated. The electrochemical characterisation of the electrode is carried out by means of cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge-discharge experiments. The specific capacitance is {approx}4.05x10{sup 2}Fg{sup -1}. This indicates the feasibility of the polyaniline-coated nickel electrode for use in electrochemical supercapacitors. (author)

  1. Caged black holes: Black holes in compactified spacetimes. I. Theory

    International Nuclear Information System (INIS)

    In backgrounds with compact dimensions there may exist several phases of black objects including a black hole and a black string. The phase transition between them raises questions and touches on fundamental issues such as topology change, uniqueness, and cosmic censorship. No analytic solution is known for the black hole, and moreover one can expect approximate solutions only for very small black holes, while phase transition physics happens when the black hole is large. Hence we turn to numerical solutions. Here some theoretical background to the numerical analysis is given, while the results will appear in a subsequent paper. The goals for a numerical analysis are set. The scalar charge and tension along the compact dimension are defined and used as improved order parameters which put both the black hole and the black string at finite values on the phase diagram. The predictions for small black holes are presented. The differential and the integrated forms of the first law are derived, and the latter (Smarr's formula) can be used to estimate the 'overall numerical error'. Field asymptotics and expressions for physical quantities in terms of the numerical values are supplied. The techniques include the 'method of equivalent charges', free energy, dimensional reduction, and analytic perturbation for small black holes

  2. 40 CFR Appendix Xii to Part 266 - Nickel or Chromium-Bearing Materials that may be Processed in Exempt Nickel-Chromium Recovery...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 26 2010-07-01 2010-07-01 false Nickel or Chromium-Bearing Materials that may be Processed in Exempt Nickel-Chromium Recovery Furnaces XII Appendix XII to Part 266... FACILITIES Pt. 266, App. XII Appendix XII to Part 266—Nickel or Chromium-Bearing Materials that may...

  3. How much radioactive nickel does ASASSN-15lh require?

    CERN Document Server

    Kozyreva, Alexandra; Blinnikov, Sergey; Hartogh, Jacqueline den

    2016-01-01

    The discovery of the most luminous supernova ASASSN-15lh triggered a shock-wave in the supernova community. The three possible mechanisms proposed for the majority of other superluminous supernovae do not produce a realistic physical model for this particular supernova. In the present study we show the limiting luminosity available from a nickel-powered pair-instability supernova. We computed a few exotic nickel-powered explosions with a total mass of nickel up to 1500 solar masses. We used the hydrostatic configurations prepared with the GENEVA and MESA codes, and the STELLA radiative-transfer code for following the explosion of these models. We show that 1500 solar masses of radioactive nickel is needed to power a luminosity of 2x10^45 erg/s. The resulting light curve is very broad and incompatible with the shorter ASASSN-15lh time-scale. This rules out a nickel-powered origin of ASASSN-15lh. In addition, we derive a simple peak luminosity - nickel mass relation from our data, which may serve to estimate of...

  4. Deformation Induced Internal Friction Peaks in Nanocrystalline Nickel

    Institute of Scientific and Technical Information of China (English)

    LI Ping-Yun; ZHANG Xi-Yan; NI Hai-Tao; CAO Zhen-Hua; MENG Xiang-Kang

    2012-01-01

    We report the mechanical spectroscopy study of the cold-rolling induced dynamical behavior of crystalline defects in nanocrystalline (NC) nickel. The results show that internal friction (IF) peaks in NC nickel can be induced by cold-rolling. An IF peak, originating from dislocation activity, occurs when the strain is in the range of 9.7-32.8%. Two Bordoni peaks occur when the strain is 39.0% and an IF peak associated with deformation twinning appears when the strain is 42.6%. These results mean that deformation of NC nickel is mediated by different kinds of defects as the strain increases.%We report the mechanical spectroscopy study of the cold-rolling induced dynamical behavior of crystalline defects in nanocrystalline (NC) nickel The results show that internal friction (IF) peaks in NC nickel can be induced by cold-rolling.An IF peak,originating from dislocation activity,occurs when the strain is in the range of 9.7- 32.8%.Two Bordoni peaks occur when the strain is 39.0% and an IF peak associated with deformation twinning appears when the strain is 42.6%.These results mean that deformation of NC nickel is mediated by different kinds of defects as the strain increases.

  5. Adsorption of nickel on synthetic hydroxyapatite from aqueous solutions

    International Nuclear Information System (INIS)

    The sorption of nickel on synthetic hydroxyapatite was investigated using a batch method and radiotracer technique. The hydroxyapatite samples used in experiments were a commercial hydroxyapatite and hydroxyapatite of high crystallinity with Ca/P ratio of 1.563 and 1.688, respectively, prepared by a wet precipitation process. The sorption of nickel on hydroxyapatite was pH independent ranging from 4.5 to 6.5 as a result of buffering properties of hydroxyapatite. The adsorption of nickel was rapid and the percentage of Ni sorption on both samples of hydroxyapatite was >98 % during the first 15-30 min of the contact time for initial Ni2+ concentration of 1 x 10-4 mol dm-3. The experimental data for sorption of nickel have been interpreted in the term of Langmuir isotherm and the value of maximum sorption capacity of nickel on a commercial hydroxyapatite and hydroxyapatite prepared by wet precipitation process was calculated to be 0.184 and 0.247 mmol g-1, respectively. The sorption of Ni2+ ions was performed by ion-exchange with Ca2+ cations on the crystal surface of hydroxyapatite under experimental conditions. The competition effect of Co2+ and Fe2+ towards Ni2+ sorption was stronger than that of Ca2+ ions. NH4+ ions have no apparent effect on nickel sorption. (author)

  6. Nickel and cobalt resistance engineered in Escherichia coli by overexpression of serine acetyltransferase from the nickel hyperaccumulator plant Thlaspi goesingense.

    Science.gov (United States)

    Freeman, John L; Persans, Michael W; Nieman, Ken; Salt, David E

    2005-12-01

    The overexpression of serine acetyltransferase from the Ni-hyperaccumulating plant Thlaspi goesingense causes enhanced nickel and cobalt resistance in Escherichia coli. Furthermore, overexpression of T. goesingense serine acetyltransferase results in enhanced sensitivity to cadmium and has no significant effect on resistance to zinc. Enhanced nickel resistance is directly related to the constitutive overactivation of sulfur assimilation and glutathione biosynthesis, driven by the overproduction of O-acetyl-L-serine, the product of serine acetyltransferase and a positive regulator of the cysteine regulon. Nickel in the serine acetyltransferase-overexpressing strains is not detoxified by coordination or precipitation with sulfur, suggesting that glutathione is involved in reducing the oxidative damage imposed by nickel. PMID:16332856

  7. Influence of chrome on the intergranular corrosion of iron-nickel-chrome alloys of high nickel concentration

    International Nuclear Information System (INIS)

    Integranular corrosion of iron-nickel-chromium alloys has been studied by means of potentiostatic attacks and observations in scanning electron microscopy. The alloys with high contents in chromium and nickel present stronger integranular corrosion. The thermal etching of the same alloys and the analysis of bibliographic data allow to conclude that an increase of chromium and nickel contents involve a decrease of the intergranular (γsub(J)) and superficial (γsub(S)) free energies. The results are interpreted on the basis of chromium segregation. The intergranular enrichment of chromium should be the more important as nickel and chromium contents are high. The influence of minor components, like carbon, is also considered specially on the chromium activity near the grain boundaries. (Auth.)

  8. Asymmetric black dyonic holes

    Directory of Open Access Journals (Sweden)

    I. Cabrera-Munguia

    2015-04-01

    Full Text Available A 6-parametric asymptotically flat exact solution, describing a two-body system of asymmetric black dyons, is studied. The system consists of two unequal counterrotating Kerr–Newman black holes, endowed with electric and magnetic charges which are equal but opposite in sign, separated by a massless strut. The Smarr formula is generalized in order to take into account their contribution to the mass. The expressions for the horizon half-length parameters σ1 and σ2, as functions of the Komar parameters and of the coordinate distance, are displayed, and the thermodynamic properties of the two-body system are studied. Furthermore, the seven physical parameters satisfy a simple algebraic relation which can be understood as a dynamical scenario, in which the physical properties of one body are affected by the ones of the other body.

  9. Black Holes and Fourfolds

    CERN Document Server

    Bena, Iosif; Vercnocke, Bert

    2012-01-01

    We establish the relation between the structure governing supersymmetric and non-supersymmetric four- and five-dimensional black holes and multicenter solutions and Calabi-Yau flux compactifications of M-theory and type IIB string theory. We find that the known BPS and almost-BPS multicenter black hole solutions can be interpreted as GKP compactifications with (2,1) and (0,3) imaginary self-dual flux. We also show that the most general GKP compactification leads to new classes of BPS and non-BPS multicenter solutions. We explore how these solutions fit into N=2 truncations, and elucidate how supersymmetry becomes camouflaged. As a necessary tool in our exploration we show how the fields in the largest N=2 truncation fit inside the six-torus compactification of eleven-dimensional supergravity.

  10. Shape of black holes

    CERN Document Server

    Clement, María E Gabach

    2015-01-01

    It is well known that celestial bodies tend to be spherical due to gravity and that rotation produces deviations from this sphericity. We discuss what is known and expected about the shape of black holes' horizons from their formation to their final, stationary state. We present some recent results showing that black hole rotation indeed manifests in the widening of their central regions, limits their global shapes and enforces their whole geometry to be close to the extreme Kerr horizon geometry at almost maximal rotation speed. The results depend only on the horizon area and angular momentum. In particular they are entirely independent of the surrounding geometry of the spacetime and of the presence of matter satisfying the strong energy condition. We also discuss the the relation of this result with the Hoop conjecture.

  11. Black-hole astrophysics

    Energy Technology Data Exchange (ETDEWEB)

    Bender, P. [Univ. of Colorado, Boulder, CO (United States); Bloom, E. [Stanford Linear Accelerator Center, Menlo Park, CA (United States); Cominsky, L. [Sonoma State Univ., Rohnert Park, CA (United States). Dept. of Physics and Astronomy] [and others

    1995-07-01

    Black-hole astrophysics is not just the investigation of yet another, even if extremely remarkable type of celestial body, but a test of the correctness of the understanding of the very properties of space and time in very strong gravitational fields. Physicists` excitement at this new prospect for testing theories of fundamental processes is matched by that of astronomers at the possibility to discover and study a new and dramatically different kind of astronomical object. Here the authors review the currently known ways that black holes can be identified by their effects on their neighborhood--since, of course, the hole itself does not yield any direct evidence of its existence or information about its properties. The two most important empirical considerations are determination of masses, or lower limits thereof, of unseen companions in binary star systems, and measurement of luminosity fluctuations on very short time scales.

  12. High temperature speciation of the nickel/iron system for use with the MULTEQ model

    International Nuclear Information System (INIS)

    High temperature solubility predictions for the nickel-iron system to calculate the precipitation of hematite, magnetite, nickel ferrites, nickel metal and nickel oxide are critical to the understanding of PWR system corrosion, corrosion product transport, and radiation field behavior. This complex system is difficult to model because of the low solubilities and possible non-stoichiometric nickel ferrite precipitates. This work reviewed the available data in the literature and derived a model for iron and nickel hydrolysis products, nickel and nickel oxide precipitates, iron oxide precipitates, and nickel ferrite precipitates. This model forms the basis of the latest revision to the EPRI MULTEQ Database, used in programs such as the EPRI MULTEQ High Temperature Chemistry Calculator. The results show an updated magnetite/nickel-ferrite/nickel system, the features of which include: The iron hydrolysis/magnetite/hematite system was re-derived from the best available data; Fe(OH)3- and Ni(OH)3- do not appear as significant species in high temperature conditions. Nickel ferrite is predicted to be the more stable product at PWR operating conditions, with iron concentrations determined by the solubility of this precipitate. Since corrosion of PWR surfaces leads to the release of excess nickel, nickel concentrations are determined by Ni/NiO solubility. (author)

  13. Noncommutative Black Holes

    CERN Document Server

    Bastos, C; Dias, N C; Prata, J N

    2010-01-01

    One considers phase-space noncommutativity in the context of a Kantowski-Sachs cosmological model to study the interior of a Schwarzschild black hole. It is shown that the potential function of the corresponding quantum cosmology problem has a local minimum. One deduces the thermodynamics and show that the Hawking temperature and entropy exhibit an explicit dependence on the momentum noncommutativity regime and it is shown that the wave function vanishes in this limit.

  14. Noncommutative Solitonic Black Hole

    OpenAIRE

    Chang-Young, Ee; Kimm, Kyoungtae; Lee, Daeho; Lee, Youngone

    2011-01-01

    We investigate solitonic black hole solutions in three dimensional noncommutative spacetime. We do this in gravity with negative cosmological constant coupled to a scalar field. Noncommutativity is realized with the Moyal product which is expanded up to first order in the noncommutativity parameter in two spatial directions. With numerical simulation we study the effect of noncommutativity by increasing the value of the noncommutativity parameter starting from commutative solutions. We find t...

  15. Infinitely Coloured Black Holes

    OpenAIRE

    Mavromatos, Nick E.; Winstanley, Elizabeth(Consortium for Fundamental Physics, School of Mathematics and Statistics, University of Sheffield, Hicks Building, Hounsfield Road, Sheffield, S3 7RH, United Kingdom)

    1999-01-01

    We formulate the field equations for $SU(\\infty)$ Einstein-Yang-Mills theory, and find spherically symmetric black-hole solutions. This model may be motivated by string theory considerations, given the enormous gauge symmetries which characterize string theory. The solutions simplify considerably in the presence of a negative cosmological constant, particularly for the limiting cases of a very large cosmological constant or very small gauge field. The situation of an arbitrarily small gauge f...

  16. Beyond the black hole

    International Nuclear Information System (INIS)

    This book is about the life and work of Stephen Hawking. It traces the development of his theories about the universe and particularly black holes, in a biographical context. Hawking's lecture 'Is the end in sight for theoretical physics' is presented as an appendix. In this, he discusses the possibility of achieving a complete, consistent and unified theory of the physical interactions which would describe all possible observations. (U.K.)

  17. Thermal BEC Black Holes

    OpenAIRE

    Roberto Casadio(INFN, Bologna); Andrea Giugno; Octavian Micu; Alessio Orlandi

    2015-01-01

    We review some features of Bose–Einstein condensate (BEC) models of black holes obtained by means of the horizon wave function formalism. We consider the Klein–Gordon equation for a toy graviton field coupled to a static matter current in a spherically-symmetric setup. The classical field reproduces the Newtonian potential generated by the matter source, while the corresponding quantum state is given by a coherent superposition of scalar modes with a continuous occupation number. An attractiv...

  18. Black holes reconsidered

    CERN Document Server

    Helfer, Adam D

    2011-01-01

    I review elements of the foundations of black-hole theory with attention to problematic issues, and describe some techniques which either seem to help with the difficulties or at least investigate their scope. The definition of black holes via event horizons has been problematic because it depends on knowing the global structure of space-time; often attempts to avoid this (e.g. apparent horizons) require knowledge of the interior geometry. I suggest studying instead the holonomy relating the exterior neighborhood of the incipient horizon to the regime of distant observers; at least in the spherically symmetric case, this holonomy will develop certain universal features, in principle observable from signals emitted from infalling objects. I discuss the theory of quantum fields in curved space-time, and the difficulties with Hawking's prediction of black-hole radiation. I then show that the usual, very natural, theory of quantum fields in curved space-time runs into difficulties when applied to measurement prob...

  19. Slowly balding black holes

    CERN Document Server

    Lyutikov, Maxim

    2011-01-01

    The "no hair" theorem, a key result in General Relativity, states that an isolated black hole is defined by only three parameters: mass, angular momentum, and electric charge; this asymptotic state is reached on a light-crossing time scale. We find that the "no hair" theorem is not formally applicable for black holes formed from collapse of a rotating neutron star. Rotating neutron stars can self-produce particles via vacuum breakdown forming a highly conducting plasma magnetosphere such that magnetic field lines are effectively "frozen-in" the star both before and during collapse. In the limit of no resistivity, this introduces a topological constraint which prohibits the magnetic field from sliding off the newly-formed event horizon. As a result, during collapse of a neutron star into a black hole, the latter conserves the number of magnetic flux tubes $N_B = e \\Phi_\\infty /(\\pi c \\hbar)$, where $\\Phi_\\infty \\approx 2 \\pi^2 B_{NS} R_{NS}^3 /(P_{\\rm NS} c)$ is the initial magnetic flux through the hemisphere...

  20. Thermal corpuscular black holes

    Science.gov (United States)

    Casadio, Roberto; Giugno, Andrea; Orlandi, Alessio

    2015-06-01

    We study the corpuscular model of an evaporating black hole consisting of a specific quantum state for a large number N of self-confined bosons. The single-particle spectrum contains a discrete ground state of energy m (corresponding to toy gravitons forming the black hole), and a gapless continuous spectrum (to accommodate for the Hawking radiation with energy ω >m ). Each constituent is in a superposition of the ground state and a Planckian distribution at the expected Hawking temperature in the continuum. We first find that, assuming the Hawking radiation is the leading effect of the internal scatterings, the corresponding N -particle state can be collectively described by a single-particle wave function given by a superposition of a total ground state with energy M =N m and a Planckian distribution for E >M at the same Hawking temperature. From this collective state, we compute the partition function and obtain an entropy which reproduces the usual area law with a logarithmic correction precisely related with the Hawking component. By means of the horizon wave function for the system, we finally show the backreaction of modes with ω >m reduces the Hawking flux. Both corrections, to the entropy and to the Hawking flux, suggest the evaporation properly stops for vanishing mass, if the black hole is in this particular quantum state.

  1. Attractors in Black

    CERN Document Server

    Bellucci, S; Marrani, A

    2008-01-01

    We review recent results in the study of attractor horizon geometries (with non-vanishing Bekenstein-Hawking entropy) of dyonic extremal d=4 black holes in supergravity. We focus on N=2, d=4 ungauged supergravity coupled to a number n_{V} of Abelian vector multiplets, outlining the fundamentals of the special Kaehler geometry of the vector multiplets' scalar manifold (of complex dimension n_{V}), and studying the 1/2-BPS attractors, as well as the non-BPS (non-supersymmetric) ones with non-vanishing central charge. For symmetric special Kaehler geometries, we present the complete classification of the orbits in the symplectic representation of the classical U-duality group (spanned by the black hole charge configuration supporting the attractors), as well as of the moduli spaces of non-BPS attractors (spanned by the scalars which are not stabilized at the black hole event horizon). Finally, we report on an analogous classification for N>2-extended, d=4 ungauged supergravities, in which also the 1/N-BPS attrac...

  2. Non-Abelian magnetic black strings versus black holes

    Science.gov (United States)

    Mazharimousavi, S. Habib; Halilsoy, M.

    2016-05-01

    We present d+1 -dimensional pure magnetic Yang-Mills (YM) black strings (or 1-branes) induced by the d -dimensional Einstein-Yang-Mills-Dilaton black holes. The Born-Infeld version of the YM field makes our starting point which goes to the standard YM field through a limiting procedure. The lifting from black holes to black strings (with less number of fields) is done by adding an extra, compact coordinate. This amounts to the change of horizon topology from S^{d-2} to a product structure. Our black string in 5 dimensions is a rather special one, with uniform Hawking temperature and non-asymptotically flat structure. As the YM charge becomes large the string gets thinner to tend into a breaking point and transform into a 4-dimensional black hole.

  3. Nickel removal from nickel-5,10,15,20-tetraphenylporphine using supercritical water in absence of catalyst: A basic study

    International Nuclear Information System (INIS)

    Reactions of nickel-5,10,15,20-tetraphenylporphine (Ni-TPP) were studied in supercritical water in the presence of toluene without the addition of any catalyst, H2 or H2S that is called a green process. The objective of this study was to remove nickel from Ni-TPP, the most common metal compound present in heavy crude, in high extent at low reaction time. All experiments were carried out in an 8.8 mL batch reactor fabricated from hastelloy C-276. The ability of supercritical water (SCW) to remove nickel from Ni-TPP was studied at temperatures of 450-490 deg, C and water partial pressures of 25-35 MPa. Water partial pressure had no effect on overall conversion at temperatures of 450 deg, C and a reaction time of 60 min. The overall Ni-TPP conversion was 89.80%, a figure above that of previous catalytic studies. The percentage of nickel removal was estimated as a function of reaction time and temperature. It were temperature 490 deg, C and pressure 25 MPa at reaction time 90 min where 65.68% nickel were removed by the action of SCW and toluene, as a co-solvent. It was determined that Ni-TPP undergoes a series of reactions, ending in demetallation and ring fragmentation. The obtained results suggest that supercritical water has a capability to remove nickel from Ni-TPP.

  4. Electron transfer behaviour of single-walled carbon nanotubes electro-decorated with nickel and nickel oxide layers

    Energy Technology Data Exchange (ETDEWEB)

    Adekunle, Abolanle S.; Ozoemena, Kenneth I. [Department of Chemistry, University of Pretoria, Pretoria 0002 (South Africa)

    2008-08-01

    The electron transfer behaviour of nickel film-decorated single-walled carbon nanotubes (SWCNTs-Ni) at edge plane pyrolytic graphite electrodes (EPPGEs) was investigated. The impact of SWCNTs on the redox properties of the nickel film was investigated with cyclic voltammetry and electrochemical impedance spectroscopy (EIS). From EIS data, obtained using ferrocyanide/ferricyanide as a redox probe, we show that the electrodes based on nickel and nickel oxide films follow electrical equivalent circuit models typical of partial charge transfer or adsorption-controlled kinetics, resembling the 'electrolyte-insulator-semiconductor sensors (EIS)'. From the models, we prove that EPPGE-SWCNT-Ni exhibits the least resistance to charge transport compared to other electrodes (approximately 30 times faster than the EPPGE-SWCNT-NiO, 25 times faster than EPPGE-SWCNT, and over 300 times faster than the bare EPPGE) suggesting the ability of the SWCNTs to act as efficient conducting species that facilitate electron transport of the integrated nickel and nickel oxide particles. (author)

  5. Homogeneous Precipitation of Nickel Hydroxide Powders

    Energy Technology Data Exchange (ETDEWEB)

    Bora Mavis

    2003-12-12

    Precipitation and characterization of nickel hydroxide powders were investigated. A comprehensive precipitation model incorporating the metal ion hydrolysis, complexation and precipitation reactions was developed for the production of the powders with urea precipitation method. Model predictions on Ni{sup 2+} precipitation rate were confirmed with precipitation experiments carried out at 90 C. Experimental data and model predictions were in remarkable agreement. Uncertainty in the solubility product data of nickel hydroxides was found to be the large contributor to the error. There were demonstrable compositional variations across the particle cross-sections and the growth mechanism was determined to be the aggregation of primary crystallites. This implied that there is a change in the intercalate chemistry of the primary crystallites with digestion time. Predicted changes in the concentrations of simple and complex ions in the solution support the proposed mechanism. The comprehensive set of hydrolysis reactions used in the model described above allows the investigation of other systems provided that accurate reaction constants are available. the fact that transition metal ions like Ni{sup 2+} form strong complexes with ammonia presents a challenge in the full recovery of the Ni{sup 2+}. On the other hand, presence of Al{sup 3+} facilitates the complete precipitation of Ni{sup 2+} in about 3 hours of digestion. A challenge in their predictive modeling studies had been the fact that simultaneous incorporation of more than one metal ion necessitates a different approach than just using the equilibrium constants of hydrolysis, complexation and precipitation reactions. Another limitation of using equilibrium constants is that the nucleation stage of digestion, which is controlled mainly by kinetics, is not fully justified. A new program released by IBM Almaden Research Center (Chemical Kinetics Simulator{trademark}, Version 1.01) lets the user change the order of

  6. Effect of biomass concentration on the biosorption of nickel by oedogonium sp

    International Nuclear Information System (INIS)

    The bioremediation of nickel pollution of the mixed metal solution containing lead, nickel and chromium has been studied by using the natural biomass of Oedogonium sp. The effect of various concentrations of the biomass show that the maximum biosorption of Nickel from the mixed metal solution occurred at 3.5g, when the concentration of Nickel pollutant was 50 ppm in a 100 ml of the mixed metal solution. The biosorption of Nickel from single metal solution show that biosorption of lead and chromium do not interfere with the biosorption of Nickel by Oedogonium sp. (author)

  7. Free ionic nickel accumulation and localization in the freshwater zooplankter, Daphnia magna

    International Nuclear Information System (INIS)

    The processes which lead to the accumulation of free ionic nickel (radioactive) from solution by Daphnia magna were studied and incorporated into a model which describes accummulation at different concentrations. Adsorption proved to be a relatively small component of nickel accummulation. The accummulation rate eventually approached zero, which represented an equilibrium between uptake and loss of nickel. However, elimination experiments did reveal a pool of relatively static nickel. The appearance and distribution of nickel within five body parts (body fluid, carapace, gut, filtering appendages, and eggs) of D. magna supported the accummulation data and added to the understanding of the pathways of nickel through the organism

  8. Fabrication of Nickel Nanotube Using Anodic Oxidation and Electrochemical Deposition Technologies and Its Hydrogen Storage Property

    Directory of Open Access Journals (Sweden)

    Yan Lv

    2016-01-01

    Full Text Available Electrochemical deposition technique was utilized to fabricate nickel nanotubes with the assistance of AAO templates. The topography and element component of the nickel nanotubes were characterized by TEM and EDS. Furthermore, the nickel nanotube was made into microelectrode and its electrochemical hydrogen storage property was studied using cyclic voltammetry. The results showed that the diameter of nickel nanotubes fabricated was around 20–100 mm, and the length of the nanotube could reach micron grade. The nickel nanotubes had hydrogen storage property, and the hydrogen storage performance was higher than that of nickel powder.

  9. II. Electrodeposition/removal of nickel in a spouted electrochemical reactor.

    Science.gov (United States)

    Grimshaw, Pengpeng; Calo, Joseph M; Shirvanian, Pezhman A; Hradil, George

    2011-08-17

    An investigation is presented of nickel electrodeposition from acidic solutions in a cylindrical spouted electrochemical reactor. The effects of solution pH, temperature, and applied current on nickel removal/recovery rate, current efficiency, and corrosion rate of deposited nickel on the cathodic particles were explored under galvanostatic operation. Nitrogen sparging was used to decrease the dissolved oxygen concentration in the electrolyte in order to reduce the nickel corrosion rate, thereby increasing the nickel electrowinning rate and current efficiency. A numerical model of electrodeposition, including corrosion and mass transfer in the particulate cathode moving bed, is presented that describes the behavior of the experimental net nickel electrodeposition data quite well. PMID:22039317

  10. Occupational hand eczema caused by nickel and evaluated by quantitative exposure assessment

    DEFF Research Database (Denmark)

    Jensen, Peter; Thyssen, Jacob Pontoppidan; Johansen, Jeanne D; Skare, Lizbet; Menné, Torkil; Lidén, Carola

    2011-01-01

    dilution series were performed. Results. Nickel was detected in all samples from the hands. In all patients, the nickel content on the hands was higher than on the non-exposed control area. Conclusions. Occupational exposure to nickel-releasing items raised the nickel content on exposed skin as compared...... with a non-exposed control site. Nickel-reducing measures led to complete symptom relief in all cases. In cases of a positive nickel patch test reaction and hand eczema, patients should perform the dimethylglyoxime (DMG) test on metallic items at home and at work. The acid wipe sampling technique is...

  11. Black Swan Tropical Cyclones

    Science.gov (United States)

    Emanuel, K.; Lin, N.

    2012-12-01

    Virtually all assessments of tropical cyclone risk are based on historical records, which are limited to a few hundred years at most. Yet stronger TCs may occur in the future and at places that have not been affected historically. Such events lie outside the realm of historically based expectations and may have extreme impacts. Their occurrences are also often made explainable after the fact (e.g., Hurricane Katrina). We nickname such potential future TCs, characterized by rarity, extreme impact, and retrospective predictability, "black swans" (Nassim Nicholas Taleb, 2007). As, by definition, black swan TCs have yet to happen, statistical methods that solely rely on historical track data cannot predict their occurrence. Global climate models lack the capability to predict intense storms, even with a resolution as high as 14 km (Emanuel et al. 2010). Also, most dynamic downscaling methods (e.g., Bender et al. 2010) are still limited in horizontal resolution and are too expensive to implement to generate enough events to include rare ones. In this study, we apply a simpler statistical/deterministic hurricane model (Emanuel et al. 2006) to simulate large numbers of synthetic storms under a given (observed or projected) climate condition. The method has been shown to generate realistic extremes in various basins (Emanuel et al. 2008 and 2010). We also apply a hydrodynamic model (ADCIRC; Luettich et al. 1992) to simulate the storm surges generated by these storms. We then search for black swan TCs, in terms of the joint wind and surge damage potential, in the generated large databases. Heavy rainfall is another important TC hazard and will be considered in a future study. We focus on three areas: Tampa Bay in the U.S., the Persian Gulf, and Darwin in Australia. Tampa Bay is highly vulnerable to storm surge as it is surrounded by shallow water and low-lying lands, much of which may be inundated by a storm tide of 6 m. High surges are generated by storms with a broad

  12. Stimulated emission and black holes

    International Nuclear Information System (INIS)

    The probability of a black hole emitting m particles when n particles are incident on the black hole was first derived by Bekenstein and Meisels, and later, using a different method, by Panangaden and Wald. In another paper by Bekenstein, it was argued that black holes should have stimulated emission in all modes including the nonsuperradiant ones. In this paper, we use a model based on quantum field theory. We show that Bose-Einstein statistics enhances the probability for particles to scatter in the same direction. We also prove that a black hole is equivalent to a perfect blackbody surrounded by a mirror. In our model, the black hole does not exhibit stimulated emission in nonsuperradiant modes. We also compare the black hole to a gray body

  13. Black Hole's 1/N Hair

    CERN Document Server

    Dvali, Gia

    2013-01-01

    According to the standard view classically black holes carry no hair, whereas quantum hair is at best exponentially weak. We show that suppression of hair is an artifact of the semi-classical treatment and that in the quantum picture hair appears as an inverse mass-square effect. Such hair is predicted in the microscopic quantum description in which a black hole represents a self-sustained leaky Bose-condensate of N soft gravitons. In this picture the Hawking radiation is the quantum depletion of the condensate. Within this picture we show that quantum black hole physics is fully compatible with continuous global symmetries and that global hair appears with the strength B/N, where B is the global charge swallowed by the black hole. For large charge this hair has dramatic effect on black hole dynamics. Our findings can have interesting astrophysical consequences, such as existence of black holes with large detectable baryonic and leptonic numbers.

  14. Black Hole Masses are Quantized

    CERN Document Server

    Dvali, Gia; Mukhanov, Slava

    2011-01-01

    We give a simple argument showing that in any sensible quantum field theory the masses of black holes cannot assume continuous values and must be quantized. Our proof solely relies on Poincare-invariance of the asymptotic background, and is insensitive to geometric characteristics of black holes or other peculiarities of the short distance physics. Therefore, our results are equally-applicable to any other localized objects on asymptotically Poincare-invariant space, such as classicalons. By adding a requirement that in large mass limit the quantization must approximately account for classical results, we derive an universal quantization rule applicable to all classicalons (including black holes) in arbitrary number of dimensions. In particular, this implies, that black holes cannot emit/absorb arbitrarily soft quanta. The effect has phenomenological model-independent implications for black holes and other classicalons that may be created at LHC. We predict, that contrary to naive intuition, the black holes a...

  15. Black hole's 1/N hair

    International Nuclear Information System (INIS)

    According to the standard view classically black holes carry no hair, whereas quantum hair is at best exponentially weak. We show that suppression of hair is an artifact of the semi-classical treatment and that in the quantum picture hair appears as an inverse mass-square effect. Such hair is predicted in the microscopic quantum description in which a black hole represents a self-sustained leaky Bose-condensate of N soft gravitons. In this picture the Hawking radiation is the quantum depletion of the condensate. Within this picture we show that quantum black hole physics is fully compatible with continuous global symmetries and that global hair appears with the strength B/N, where B is the global charge swallowed by the black hole. For large charge this hair has dramatic effect on black hole dynamics. Our findings can have interesting astrophysical consequences, such as existence of black holes with large detectable baryonic and leptonic numbers

  16. Small black holes on cylinders

    International Nuclear Information System (INIS)

    We find the metric of small black holes on cylinders, i.e. neutral and static black holes with a small mass in d-dimensional Minkowski space times a circle. The metric is found using an ansatz for black holes on cylinders proposed in J. High Energy Phys. 05, 032 (2002). We use the new metric to compute corrections to the thermodynamics which is seen to deviate from that of the (d+1)-dimensional Schwarzschild black hole. Moreover, we compute the leading correction to the relative binding energy which is found to be non-zero. We discuss the consequences of these results for the general understanding of black holes and we connect the results to the phase structure of black holes and strings on cylinders

  17. Shock induced crystallization of amorphous Nickel powders

    Science.gov (United States)

    Cherukara, Mathew; Strachan, Alejandro

    2015-06-01

    Recent experimental work has shown the efficacy of amorphous Ni/crystalline Al composites as energetic materials, with flame velocities twice that of a comparable crystalline Ni/crystalline Al system. Of further interest is the recrystallization mechanisms in the pure amorphous Ni powders, both thermally induced and mechanically induced. We present large-scale molecular dynamics simulations of shock-induced recrystallization in loosely packed amorphous Nickel powders. We study the time dependent nucleation and growth processes by holding the shocked samples at the induced pressures and temperatures for extended periods following the passage of the shock (up to 6 ns). We find that the nanostructure of the recrystallized Ni and time scales of recrystallization are dependent on the piston velocity. At low piston velocities, nucleation events are rare, leading to long incubation times and a relatively coarse nanostructure. At higher piston velocities, local variations in temperature due to jetting phenomena and void collapse, give rise to multiple nucleation events on time scales comparable to the passage of the shock wave, leading to the formation of a fine-grained nanostructure. Interestingly, we observe that the nucleation and growth process occurs in two steps, with the first nuclei crystallizing into the BCC structure, before evolving over time into the expected FCC structure. U.S. Defense Threat Reduction Agency, HDTRA1-10-1-0119 (Program Manager Suhithi Peiris).

  18. Nickel hydrogen low earth orbit life testing

    Science.gov (United States)

    Badcock, Charles C.; Haag, R. L.

    1988-02-01

    A program to demonstrate the long-term reliability of nickel hydrogen (NiH2) cells in low earth orbit (LEO) and support use in mid-altitude orbit (MAO) has been initiated. Both 3.5 and 4.5 in. diameter NiH2 cells are included in the test plan. Cells from all U.S. vendors are to be tested. The tests will be performed at -5 and 10 C at 40 and 60 percent depth of discharge (DOD) for LEO orbit and 10 C and 80 percent DOD for MAO orbit simulations. The goals of the testing are 20,000 cycles at 60 percent DOD and 30,000 cycles at 40 percent DOD. Cells are presently undergoing acceptance and characterization testing at Naval Weapons Support Center (NWSC), Crane, Indiana. Funding has been provided by the Air Force Space Technology Center (AFSTC) and two AF System Program Offices (SPO's) to initiate the testing, but additional funding must be acquired to complete the purchase of cells and to assure completion of the testing.

  19. Cytotoxicity and intracellular dissolution of nickel nanowires.

    Science.gov (United States)

    Perez, Jose E; Contreras, Maria F; Vilanova, Enrique; Felix, Laura P; Margineanu, Michael B; Luongo, Giovanni; Porter, Alexandra E; Dunlop, Iain E; Ravasi, Timothy; Kosel, Jürgen

    2016-09-01

    The assessment of cytotoxicity of nanostructures is a fundamental step for their development as biomedical tools. As widely used nanostructures, nickel nanowires (Ni NWs) seem promising candidates for such applications. In this work, Ni NWs were synthesized and then characterized using vibrating sample magnetometry, energy dispersive X-Ray analysis, and electron microscopy. After exposure to the NWs, cytotoxicity was evaluated in terms of cell viability, cell membrane damage, and induced apoptosis/necrosis on the model human cell line HCT 116. The influence of NW to cell ratio (10:1 to 1000:1) and exposure times up to 72 hours was analyzed for Ni NWs of 5.4 μm in length, as well as for Ni ions. The results show that cytotoxicity markedly increases past 24 hours of incubation. Cellular uptake of NWs takes place through the phagocytosis pathway, with a fraction of the dose of NWs dissolved inside the cells. Cell death results from a combination of apoptosis and necrosis, where the latter is the outcome of the secondary necrosis pathway. The cytotoxicity of Ni ions and Ni NWs dissolution studies suggest a synergistic toxicity between NW aspect ratio and dissolved Ni, with the cytotoxic effects markedly increasing after 24 hours of incubation. PMID:26692167

  20. Creep deformation of TD--nickel chromium

    International Nuclear Information System (INIS)

    The creep behavior of thoria dispersed nickel-chromium (TD-NiCr) was examined at 10930C. Major emphasis was placed on 1) the effects of the material and the test related variables (grain size, temperature, stress, strain and strain rate) on the deformation characteristics, and 2) the evaluation of single crystal TD-NiCr material produced by a directional recrystallization technique. Creep activation enthalpies were found to increase with increasing grain size reaching maximum values for the single crystal TD-NiCr. Stress exponent of the steady state creep rate was also significantly higher for the single crystal material as compared with that determined for the polycrystalline TD-NiCr. The elevated temperature deformation of TD-NiCr was analyzed in terms of two parallel-concurrent processes: 1) diffusion controlled grain boundary sliding and 2) dislocation motion. The characteristics of the dislocation motion deformation mode (as observed in the single crystal TD-NiCr) suggest that strong particle-dislocation interactions are present. The relative contributions of dislocation motion and grain boundary sliding in TD-NiCr were estimated. In creep, grain boundary sliding was found to predominate for the small, equiaxed grain structures, whereas the dislocation deformation mode became significant for only the large grain TD-NiCr and the single crystal material

  1. Challenges of nickel silicidation in CMOS technologies

    Energy Technology Data Exchange (ETDEWEB)

    Breil, Nicolas [IBM Semiconductor Research and Development Center (SRDC), East Fishkill, NY (United States); Lavoie, Christian [IBM T.J. Watson Research Center, Yorktown Heights, NY (United States); Ozcan, Ahmet [IBM Semiconductor Research and Development Center (SRDC), East Fishkill, NY (United States); Baumann, Frieder [IBM Semiconductor Research and Development Center (SRDC), East Fishkill, NY (United States); Klymko, Nancy [IBM Semiconductor Research and Development Center (SRDC), East Fishkill, NY (United States); Nummy, Karen [IBM Semiconductor Research and Development Center (SRDC), East Fishkill, NY (United States); Sun, Bing [IBM Semiconductor Research and Development Center (SRDC), East Fishkill, NY (United States); Jordan-Sweet, Jean [IBM T.J. Watson Research Center, Yorktown Heights, NY (United States); Yu, Jian [IBM Semiconductor Research and Development Center (SRDC), East Fishkill, NY (United States); Zhu, Frank [IBM Semiconductor Research and Development Center (SRDC), East Fishkill, NY (United States); Narasimha, Shreesh [IBM Semiconductor Research and Development Center (SRDC), East Fishkill, NY (United States); Chudzik, Michael [IBM Semiconductor Research and Development Center (SRDC), East Fishkill, NY (United States)

    2015-04-01

    In our paper, we review some of the key challenges associated with the Ni silicidation process in the most recent CMOS technologies. The introduction of new materials (e.g.SiGe), and of non-planar architectures bring some important changes that require fundamental investigation from a material engineering perspective. Following a discussion of the device architecture and silicide evolution through the last CMOS generations, we focus our study on a very peculiar defect, termed NiSi-Fangs. We describe a mechanism for the defect formation, and present a detailed material analysis that supports this mechanism. We highlight some of the possible metal enrichment processes of the nickel monosilicide such as oxidation or various RIE (Reactive Ion Etching) plasma process, leading to a metal source available for defect formation. Furthermore, we investigate the NiSi formation and re-formation silicidation differences between Si and SiGe materials, and between (1 0 0) and (1 1 1) orientations. Finally, we show that the thermal budgets post silicidation can lead to the formation of NiSi-Fangs if the structure and the processes are not optimized. Beyond the understanding of the defect and the discussion on the engineering solutions used to prevent its formation, the interest of this investigation also lies in the fundamental learning within the Ni–Pt–Si–Ge system and some additional perspective on Ni-based contacts to advanced microelectronic devices.

  2. Impacts of Nickel Nanoparticles on Mineral Carbonation

    Directory of Open Access Journals (Sweden)

    Marius Bodor

    2014-01-01

    Full Text Available This work presents experimental results regarding the use of pure nickel nanoparticles (NiNP as a mineral carbonation additive. The aim was to confirm if the catalytic effect of NiNP, which has been reported to increase the dissolution of CO2 and the dissociation of carbonic acid in water, is capable of accelerating mineral carbonation processes. The impacts of NiNP on the CO2 mineralization by four alkaline materials (pure CaO and MgO, and AOD and CC steelmaking slags, on the product mineralogy, on the particle size distribution, and on the morphology of resulting materials were investigated. NiNP-containing solution was found to reach more acidic pH values upon CO2 bubbling, confirming a higher quantity of bicarbonate ions. This effect resulted in acceleration of mineral carbonation in the first fifteen minutes of reaction time when NiNP was present. After this initial stage, however, no benefit of NiNP addition was seen, resulting in very similar carbonation extents after one hour of reaction time. It was also found that increasing solids content decreased the benefit of NiNP, even in the early stages. These results suggest that NiNP has little contribution to mineral carbonation processes when the dissolution of alkaline earth metals is rate limiting.

  3. Microstructural evolution in pulse plated nickel electrodeposits

    Energy Technology Data Exchange (ETDEWEB)

    El-Sherik, A.M. [Queens Univ., Kingston, Ont. (Canada). Dept. of Mater. and Metall. Eng.; Erb, U. [Queens Univ., Kingston, Ont. (Canada). Dept. of Mater. and Metall. Eng.; Page, J. [Queen`s Univ., Kingston, ON (Canada). Dept. of Chemistry

    1997-01-01

    Square-wave cathodic current modulation was used to electrodeposit ultra-fine-grained nickel from an additive-free Watts bath. The influence of pulse parameters, namely, pulse on-time, off-time and peak current density on the grain size, surface morphology and crystal orientation was determined. The study showed that an increase in peak current density resulted in considerable refinement in crystal size of the deposit. The crystal orientation progressively changed from an almost random distribution at the lowest peak current density of 400 mA cm{sup -2} to a strong (200) texture at a peak current density of 1600 mA cm{sup -2}. At constant peak current density and off-time, the crystal size of the deposit was found initially to decrease with pulse on-time before it started to increase with further increase in on-time. The crystal orientation progressively changed from an almost random distribution at the shortest on-time of 1 ms to a strong (200) fibre texture at an on-time of 8 ms. An increase in the pulse off-time at constant on-time and peak current density resulted in a progressive increase in crystal size. However, the crystal orientation remained unaffected with increasing off-time. (orig.)

  4. Coprecipitated nickel-alumina methanation catalysts

    International Nuclear Information System (INIS)

    In the last few years there has been a renewed interest in the methanation reaction CO+3H2=CH4+H2O. The investigations described in this thesis were performed in relation to the application of this reaction, within the framework of the so-called 'NFE' project, also called 'ADAM' and 'EVA' project. This project, which has been under investigation in West Germany for some years, aims at the investigation of the feasibility of transporting heat from a nuclear high temperature reactor by means of a chemical cycle. A promising possibility to realize such a cycle exists in applying the combination of the endothermic steam reforming of methane and the exothermic methanation reaction. This thesis describes the investigations into a certain type of methanation catalyst, viz. a coprecipitated nickel-alumina catalyst, with the aim to give more insight into the interrelationship between the preparation conditions on the one hand and catalyst properties such as activity and stability on the other hand. (Auth.)

  5. Cytotoxicity and intracellular dissolution of nickel nanowires

    KAUST Repository

    Perez, Jose E.

    2015-12-22

    The assessment of cytotoxicity of nanostructures is a fundamental step for their development as biomedical tools. As widely used nanostructures, nickel nanowires (Ni NWs) seem promising candidates for such applications. In this work, Ni NWs were synthesized and then characterized using vibrating sample magnetometry, energy dispersive X-Ray analysis and electron microscopy. After exposure to the NWs, cytotoxicity was evaluated in terms of cell viability, cell membrane damage and induced apoptosis/necrosis on the model human cell line HCT 116. The influence of NW to cell ratio (10:1 to 1000:1) and exposure times up to 72 hours was analyzed for Ni NWs of 5.4 µm in length, as well as for Ni ions. The results show that cytotoxicity markedly increases past 24 hours of incubation. Cellular uptake of NWs takes place through the phagocytosis pathway, with a fraction of the dose of NWs dissolved inside the cells. Cell death results from a combination of apoptosis and necrosis, where the latter is the outcome of the secondary necrosis pathway. The cytotoxicity of Ni ions and Ni NWs dissolution studies suggest a synergistic toxicity between NW aspect ratio and dissolved Ni, with the cytotoxic effects markedly increasing after 24 hours of incubation.

  6. Hot corrosion of the B2 nickel aluminides

    Science.gov (United States)

    Ellis, David L.

    1993-01-01

    The hot corrosion behavior of the B2 nickel aluminides was studied to determine the inherent hot corrosion resistance of the beta nickel aluminides and to develop a mechanism for the hot corrosion of the beta nickel aluminides. The effects of the prior processing of the material, small additions of zirconium, stoichiometry of the materials, and preoxidation of the samples were also examined. Additions of 2, 5, and 15 w/o chromium were used to determine the effect of chromium on the hot corrosion of the beta nickel aluminides and the minimum amount of chromium necessary for good hot corrosion resistance. The results indicate that the beta nickel aluminides have inferior inherent hot corrosion resistance despite their excellent oxidation resistance. Prior processing and zirconium additions had no discernible effect on the hot corrosion resistance of the alloys. Preoxidation extended the incubation period of the alloys only a few hours and was not considered to be an effective means of stopping hot corrosion. Stoichiometry was a major factor in determining the hot corrosion resistance of the alloys with the higher aluminum alloys having a definitely superior hot corrosion resistance. The addition of chromium to the alloys stopped the hot corrosion attack in the alloys tested. From a variety of experimental results, a complex hot corrosion mechanism was proposed. During the early stages of the hot corrosion of these alloys the corrosion is dominated by a local sulphidation/oxidation form of attack. During the intermediate stages of the hot corrosion, the aluminum depletion at the surface leads to a change in the oxidation mechanism from a protective external alumina layer to a mixed nickel-aluminum spinel and nickel oxide that can occur both externally and internally. The material undergoes extensive cracking during the later portions of the hot corrosion.

  7. Rapid prototyped porous nickel-titanium scaffolds as bone substitutes.

    Science.gov (United States)

    Hoffmann, Waldemar; Bormann, Therese; Rossi, Antonella; Müller, Bert; Schumacher, Ralf; Martin, Ivan; de Wild, Michael; Wendt, David

    2014-01-01

    While calcium phosphate-based ceramics are currently the most widely used materials in bone repair, they generally lack tensile strength for initial load bearing. Bulk titanium is the gold standard of metallic implant materials, but does not match the mechanical properties of the surrounding bone, potentially leading to problems of fixation and bone resorption. As an alternative, nickel-titanium alloys possess a unique combination of mechanical properties including a relatively low elastic modulus, pseudoelasticity, and high damping capacity, matching the properties of bone better than any other metallic material. With the ultimate goal of fabricating porous implants for spinal, orthopedic and dental applications, nickel-titanium substrates were fabricated by means of selective laser melting. The response of human mesenchymal stromal cells to the nickel-titanium substrates was compared to mesenchymal stromal cells cultured on clinically used titanium. Selective laser melted titanium as well as surface-treated nickel-titanium and titanium served as controls. Mesenchymal stromal cells had similar proliferation rates when cultured on selective laser melted nickel-titanium, clinically used titanium, or controls. Osteogenic differentiation was similar for mesenchymal stromal cells cultured on the selected materials, as indicated by similar gene expression levels of bone sialoprotein and osteocalcin. Mesenchymal stromal cells seeded and cultured on porous three-dimensional selective laser melted nickel-titanium scaffolds homogeneously colonized the scaffold, and following osteogenic induction, filled the scaffold's pore volume with extracellular matrix. The combination of bone-related mechanical properties of selective laser melted nickel-titanium with its cytocompatibility and support of osteogenic differentiation of mesenchymal stromal cells highlights its potential as a superior bone substitute as compared to clinically used titanium. PMID:25383165

  8. Information Storage in Black Holes

    OpenAIRE

    Maia, M. D.

    2005-01-01

    The information loss paradox for Schwarzschild black holes is examined, using the ADS/CFT correspondence extended to the $M_6 (4,2)$ bulk. It is found that the only option compatible with the preservation of the quantum unitarity is when a regular remnant region of the black hole survives to the black hole evaporation process, where information can be stored and eventually retrieved.

  9. Origin of supermassive black holes

    OpenAIRE

    Dokuchaev, V. I.; Eroshenko, Yu. N.; Rubin, S. G.

    2007-01-01

    The origin of supermassive black holes in the galactic nuclei is quite uncertain in spite of extensive set of observational data. We review the known scenarios of galactic and cosmological formation of supermassive black holes. The common drawback of galactic scenarios is a lack of time and shortage of matter supply for building the supermassive black holes in all galaxies by means of accretion and merging. The cosmological scenarios are only fragmentarily developed but propose and pretend to...

  10. Brane-world black holes

    International Nuclear Information System (INIS)

    In this talk, I present and discuss a number of attempts to construct black hole solutions in models with Warped Extra Dimensions. Then, a contact is made with models with Large Extra Dimensions, where black-hole solutions are easily constructed - here the focus will be on the properties of microscopic black holes and the possibility of using phenomena associated with them, such as the emission of Hawking radiation, to discover fundamental properties of our spacetime.

  11. Black holes and the multiverse

    Science.gov (United States)

    Garriga, Jaume; Vilenkin, Alexander; Zhang, Jun

    2016-02-01

    Vacuum bubbles may nucleate and expand during the inflationary epoch in the early universe. After inflation ends, the bubbles quickly dissipate their kinetic energy; they come to rest with respect to the Hubble flow and eventually form black holes. The fate of the bubble itself depends on the resulting black hole mass. If the mass is smaller than a certain critical value, the bubble collapses to a singularity. Otherwise, the bubble interior inflates, forming a baby universe, which is connected to the exterior FRW region by a wormhole. A similar black hole formation mechanism operates for spherical domain walls nucleating during inflation. As an illustrative example, we studied the black hole mass spectrum in the domain wall scenario, assuming that domain walls interact with matter only gravitationally. Our results indicate that, depending on the model parameters, black holes produced in this scenario can have significant astrophysical effects and can even serve as dark matter or as seeds for supermassive black holes. The mechanism of black hole formation described in this paper is very generic and has important implications for the global structure of the universe. Baby universes inside super-critical black holes inflate eternally and nucleate bubbles of all vacua allowed by the underlying particle physics. The resulting multiverse has a very non-trivial spacetime structure, with a multitude of eternally inflating regions connected by wormholes. If a black hole population with the predicted mass spectrum is discovered, it could be regarded as evidence for inflation and for the existence of a multiverse.

  12. Statistical Hair on Black Holes

    International Nuclear Information System (INIS)

    The Bekenstein-Hawking entropy for certain BPS-saturated black holes in string theory has recently been derived by counting internal black hole microstates at weak coupling. We argue that the black hole microstate can be measured by interference experiments even in the strong coupling region where there is clearly an event horizon. Extracting information which is naively behind the event horizon is possible due to the existence of statistical quantum hair carried by the black hole. This quantum hair arises from the arbitrarily large number of discrete gauge symmetries present in string theory. copyright 1996 The American Physical Society

  13. Pyrolytic carbon coated black silicon.

    Science.gov (United States)

    Shah, Ali; Stenberg, Petri; Karvonen, Lasse; Ali, Rizwan; Honkanen, Seppo; Lipsanen, Harri; Peyghambarian, N; Kuittinen, Markku; Svirko, Yuri; Kaplas, Tommi

    2016-01-01

    Carbon is the most well-known black material in the history of man. Throughout the centuries, carbon has been used as a black material for paintings, camouflage, and optics. Although, the techniques to make other black surfaces have evolved and become more sophisticated with time, carbon still remains one of the best black materials. Another well-known black surface is black silicon, reflecting less than 0.5% of incident light in visible spectral range but becomes a highly reflecting surface in wavelengths above 1000 nm. On the other hand, carbon absorbs at those and longer wavelengths. Thus, it is possible to combine black silicon with carbon to create an artificial material with very low reflectivity over a wide spectral range. Here we report our results on coating conformally black silicon substrate with amorphous pyrolytic carbon. We present a superior black surface with reflectance of light less than 0.5% in the spectral range of 350 nm to 2000 nm. PMID:27174890

  14. Higher dimensional extremal black strings

    OpenAIRE

    H. W. Lee; Myung, Y. S.; Kim, Jin Young; Park, D. K.

    1996-01-01

    We investigate the five and six-dimensional black strings within Einstein-Maxwell theory. The extremal black strings are endowed with the null Killing symmetry. We study the propagation of Einstein-Maxwell modes in the extremal black string background by using this symmetry. It turns out that one graviton is a propagating mode, while both the Maxwell $F$ and three-form $H$ fields are non-propagating modes. Further we discuss the stability and classical hair of the extremal black strings.

  15. How black holes saved relativity

    Science.gov (United States)

    Prescod-Weinstein, Chanda

    2016-02-01

    While there have been many popular-science books on the historical and scientific legacy of Albert Einstein's general theory of relativity, a gap exists in the literature for a definitive, accessible history of the theory's most famous offshoot: black holes. In Black Hole, the science writer Marcia Bartusiak aims for a discursive middle ground, writing solely about black holes at a level suitable for both high-school students and more mature readers while also giving some broader scientific context for black-hole research.

  16. Black report up-date

    International Nuclear Information System (INIS)

    In 1984, the Black Report published its results on the incidence of cancer and leukaemia in under 25-year olds in the village of Seascale and the surrounding area near the Sellafield nuclear reprocessing plant. Since then the pressure group core, as a result of their own independent research, has discovered ten additional cases of childhood cancer which should have been included in the Black Report and a Further two cases since the Black Report was written. This represents an additional 31% over the initial numbers considered and a review of the Black Report is sought. (UK)

  17. Thermodynamics of Accelerating Black Holes

    CERN Document Server

    Appels, Michael; Kubiznak, David

    2016-01-01

    We address a long-standing problem of describing the thermodynamics of a charged accelerating black hole. We derive a standard first law of black hole thermodynamics, with the usual identification of entropy proportional to the area of the event horizon -- even though the event horizon contains a conical singularity. This result not only extends the applicability of black hole thermodynamics to realms previously not anticipated, it also opens a possibility for studying novel properties of an important class of exact radiative solutions of Einstein equations describing accelerated objects. We discuss the thermodynamic volume, stability and phase structure of these black holes.

  18. Size-controlled synthesis of monodisperse nickel nanoparticles and investigation of their magnetic and catalytic properties

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Yuan; Jia, Rongrong; Zhao, Jinchong; Liang, Jilei; Liu, Yunqi, E-mail: liuyq@upc.edu.cn; Liu, Chenguang

    2014-10-15

    Graphical abstract: - Highlights: • Monodisperse nickel nanoparticles (NPs) with different size were synthesized via the thermal decomposition approach. • The size of nickel NPs can easily be controlled by changing synthetic conditions. • The possible growth mechanism of nickel NPs was proposed. • The as-synthesized nickel NPs exhibited superparamagnetism characteristics at room temperature, and the saturation magnetization increased significantly with increasing size of the nickel NPs. • The dehydrogenation reaction of cyclohexane on nickel NPs was structure sensitive reaction. - Abstract: Monodisperse nickel nanoparticles (NPs) with different size were synthesized via the thermal decomposition approach using nickel acetylacetonate as precursors and trioctylphosphine as surfactant in oleylamine. The structure and morphology of as-synthesized nickel NPs were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and selected area electron diffraction (SAED). The surface states of as-synthesized nickel NPs were characterized by Fourier transform infrared (FT-IR) spectra. The textural properties of as-synthesized nickel NPs were characterized by N{sub 2} adsorption–desorption. The size of as-synthesized nickel NPs was found to be easily controlled by changing synthetic conditions, including P:Ni precursor ratio, reaction temperature, reaction time and oleylamine quantity, and the possible growth mechanism of nickel NPs was proposed. In addition, the magnetic measurements showed that the as-synthesized nickel NPs exhibited superparamagnetism characteristics at room temperature, and the saturation magnetization increased significantly with the increase in nickel NPs’ size. Finally, the size-dependent catalytic properties of nickel NPs for cyclohexane dehydrogenation reaction were studied. The results demonstrated that the catalytic activity can be enhanced by decreasing the size of NPs, which indicated that the dehydrogenation

  19. Preparation and study on performance of submicron nickel powder for multilayer chip positive temperature coefficient resistance

    Institute of Scientific and Technical Information of China (English)

    Chen Yong; Gong Shu-Ping; Fu Qiu-Yun; Zheng Zhi-Ping; Huang Ri-Ming; Su Peng

    2010-01-01

    Base metal nickel is often used as the inner electrode in multilayer chip positive temperature coefficient resistance (PTCR). The fine grain of ceramic powders and base metal nickel are necessary. This paper uses reducing hydrazine to gain submicron nickel powder whose diameter was 200-300 nm through adjusting the consumption of nucleating agent PVP properly. The submicron nickel powder could disperse well and was fit for co-fired of multilayer chip PTCR. It analyes the submicron nickel powder through x-ray Diffraction (XRD) and calculates the diameter of nickel by PDF cards. Using XRD analyses it obtains several conclusions:If the molar ratio of hydrazine hydrate and nickel sulfate is kept to be a constant, when enlarging the molar ratio of NaOH/Ni2+>, the diameter of nickel powder would become smaller. When the temperature in the experiment raises to 70-80 ℃, nickel powder becomes smaller too. And if the molar ratio of NaOH/Ni2+> is 4, when molar ratio of (C2>H5>O)2>/Ni2+> increases, the diameter of nickel would reduce.Results from viewing the powders by optical microscope should be the fact that the electrode made by submicron nickel powder has a better formation and compactness. Furthermore, the sheet resistance testing shows that the electrode made by submicron nickel is smaller than that made by micron nickel.

  20. Nickel oxide sol-gel films from nickel diacetate for electrochromic applications

    International Nuclear Information System (INIS)

    Nickel diacetate tetrahydrate, [Ni(acetate)2·4H2O] and nickel diacetate dimethylaminoethanol, [Ni(acetate)2(dmaeH)2] were successfully used to deposit NiOx thin films on conductive glass substrates by sol-gel techniques for large area electrochromic applications. Homogeneous one layer films 100 nm thick were deposited by spin coating 0.5 M [Ni(acetate)2·4H2O] in dmaeH at 1000 rpm and by dip coating methods. The NiOx films were characterised by X-ray diffraction, transmission electron microscopy and atomic force microscopy. The thin film electrochromic performances were characterised by means of optical (transmittance) and electrochemical (cyclic voltammetry) methods. On early cycling NiOx thin films present an activation period, related to an increase in capacity. The electro-optical data show an increase in the electrochromic response (i.e. an increase in contrast and colouration efficiency) upon cycling. Following this initial activation period a steady state is reached in which the thin films reversibly switch from transparent to brown. The anodically coloured NiOx thin films are therefore suitable for use in a complete electrochromic cell with tungsten oxide as the cathodic colouring layer. However, the films are not fully stable with long cycling

  1. Nickel oxide sol-gel films from nickel diacetate for electrochromic applications

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Miquel, J.L.; Zhang, Q.; Allen, S.J.; Rougier, A.; Blyr, A.; Davies, H.O.; Jones, A.C.; Leedham, T.J.; Williams, P.A.; Impey, S.A

    2003-01-31

    Nickel diacetate tetrahydrate, [Ni(acetate){sub 2}{center_dot}4H{sub 2}O] and nickel diacetate dimethylaminoethanol, [Ni(acetate){sub 2}(dmaeH){sub 2}] were successfully used to deposit NiO{sub x} thin films on conductive glass substrates by sol-gel techniques for large area electrochromic applications. Homogeneous one layer films 100 nm thick were deposited by spin coating 0.5 M [Ni(acetate){sub 2}{center_dot}4H{sub 2}O] in dmaeH at 1000 rpm and by dip coating methods. The NiO{sub x} films were characterised by X-ray diffraction, transmission electron microscopy and atomic force microscopy. The thin film electrochromic performances were characterised by means of optical (transmittance) and electrochemical (cyclic voltammetry) methods. On early cycling NiO{sub x} thin films present an activation period, related to an increase in capacity. The electro-optical data show an increase in the electrochromic response (i.e. an increase in contrast and colouration efficiency) upon cycling. Following this initial activation period a steady state is reached in which the thin films reversibly switch from transparent to brown. The anodically coloured NiO{sub x} thin films are therefore suitable for use in a complete electrochromic cell with tungsten oxide as the cathodic colouring layer. However, the films are not fully stable with long cycling.

  2. Controlled synthesis and magnetic properties of nickel phosphide and bimetallic iron-nickel phosphide nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Bhupendra; Ho, Chia-Ling [National Cheng Kung University, Department of Chemical Engineering, Taiwan (China); Tseng, Yuan-Chieh [National Chiao Tung University, Department of Materials Science and Engineering, Taiwan (China); Lo, Chieh-Tsung, E-mail: tsunglo@mail.ncku.edu.tw [National Cheng Kung University, Department of Chemical Engineering, Taiwan (China)

    2012-02-15

    Nickel phosphide (Ni{sub 2}P) and bimetallic iron-nickel phosphides [(Fe{sub x}Ni{sub y}){sub 2}P] nanorods were fabricated by a seeded growth strategy. This strategy utilized pre-synthesized Fe{sub 3}O{sub 4} nanoparticles as seeds and the thermal decomposition of metal precursors by multiple injections in a solution containing trioctylphosphine and didodecyldimethylammonium bromide (DDAB). The nanorods were characterized by transmission electron microscopy, X-ray diffraction, and magnetic measurements were carried out using superconducting quantum interference device (SQUID). The rod length was tunable, ranging from 10 to 110 nm depending on the number of injections, whereas the diameter of the rods was nearly 6 nm. It was found that the rod size increased with the number of injections under the constant total injection concentration and reaction time. In addition, the effect of the DDAB quantity used as a co-surfactant was studied, which showed that an optimum quantity was required to achieve uniform nanorods. Magnetic characterizations were performed over the two kinds of nanorods to identify their respective magnetic phases. The results demonstrated that the Ni{sub 2}P nanorods were defined as a Curie-Weiss paramagnet, whereas the (Fe{sub x}Ni{sub y}){sub 2}P nanorods exhibited superparamagnetic characteristics.

  3. Toxicity of nickel in the marine calanoid copepod Acartia tonsa: Nickel chloride versus nanoparticles.

    Science.gov (United States)

    Zhou, C; Vitiello, V; Casals, E; Puntes, V F; Iamunno, F; Pellegrini, D; Changwen, W; Benvenuto, G; Buttino, I

    2016-01-01

    Nickel compounds are widely used in industries and have been massively introduced in the environment in different chemical forms. Here we report the effect of two different chemical forms of nickel, NiCl2 and nickel nanoparticles (NiNPs), on the reproduction of the marine calanoid copepod Acartia tonsa. The behavior of nickel nanoparticles was analyzed with different techniques and with two protocols. In the "sonicated experiment" (SON) NiNP solution was sonicated while in the "non-sonicated experiment" (NON-SON) the solution was vigorously shaken by hand. Final nominal concentrations of 5, 10 and 50mgL(-1) and 1, 5 and 10mgL(-1) NiNPs were used for the acute and semichronic tests, respectively. Nanoparticle size did not change over time except for the highest concentration of 50mgL(-1) NiNPs, in which the diameter increased up to 843nm after 48h. The concentration of Ni dissolved in the water increased with NP concentration and was similar for SON and NON-SON solutions. Our results indicate that sonication does not modify toxicity for the copepod A. tonsa. Mean EC50 values were similar for NON-SON (20.2mgL(-1)) and SON experiments (22.14mgL(-1)) in the acute test. Similarly, no differences occurred between the two different protocols in the semichronic test, with an EC50 of 7.45mgL(-1) and 6.97mgL(-1) for NON-SON and SON experiments, respectively. Acute and semichronic tests, conducted exposing A. tonsa embryos to NiCl2 concentrations from 0.025 to 0.63mgL(-1), showed EC50 of 0.164 and 0.039mgL(-1), respectively. Overall, A. tonsa is more sensitive to NiCl2 than NiNPs with EC50 being one order of magnitude higher for NiNPs. Finally, we exposed adult copepods for 4 days to NiCl2 and NiNPs (chronic exposure) to study the effect on fecundity in terms of daily egg production and naupliar viability. Egg production is not affected by either form of nickel, whereas egg viability is significantly reduced by 0.025mgL(-1) NiCl2 and by 8.5mgL(-1) NiNPs. At NiNP concentration

  4. Thermal BEC Black Holes

    Science.gov (United States)

    Casadio, Roberto; Giugno, Andrea; Micu, Octavian; Orlandi, Alessio

    2015-10-01

    We review some features of BEC models of black holes obtained by means of the HWF formalism. We consider the KG equation for a toy graviton field coupled to a static matter current in spherical symmetry. The classical field reproduces the Newtonian potential generated by the matter source, while the corresponding quantum state is given by a coherent superposition of scalar modes with continuous occupation number. An attractive self-interaction is needed for bound states to form, so that (approximately) one mode is allowed, and the system of N bosons can be self-confined in a volume of the size of the Schwarzschild radius. The HWF is then used to show that the radius of such a system corresponds to a proper horizon. The uncertainty in the size of the horizon is related to the typical energy of Hawking modes: it decreases with the increasing of the black hole mass (larger number of gravitons), in agreement with semiclassical calculations and different from a single very massive particle. The spectrum contains a discrete ground state of energy $m$ (the bosons forming the black hole), and a continuous spectrum with energy $\\omega > m$ (representing the Hawking radiation and modelled with a Planckian distribution at the expected Hawking temperature). The $N$-particle state can be collectively described by a single-particle wave-function given by a superposition of a total ground state with energy $M = N m$ and a Planckian distribution for $E > M$ at the same Hawking temperature. The partition function is then found to yield the usual area law for the entropy, with a logarithmic correction related with the Hawking component. The backreaction of modes with $\\omega > m$ is also shown to reduce the Hawking flux and the evaporation properly stops for vanishing mass.

  5. Toxicology and metabolism of nickel compounds: comprehensive report of overall activities during the three-year period from December 1, 1977 to November 30, 1980

    Energy Technology Data Exchange (ETDEWEB)

    Sunderman, Jr, F W

    1980-08-15

    The main research accomplishments during the past three years are summarized. The principle areas of investigation are: 1. embryotoxicity, teratogenicity, and mutagenicity of nickel carbonyl; 2. metabolism, detoxification, and excretion of nickel compounds; 3. studies of nickel carcinogenesis; 4. nickel analysis in body fluids and tissues to monitor occupational exposures; 5. nephrotoxicity of nickel compounds; and 6. hematological effects of nickel compounds. (ACR)

  6. Nanoscale investigation of the interface situation of plated nickel and thermally formed nickel silicide for silicon solar cell metallization

    Science.gov (United States)

    Mondon, A.; Wang, D.; Zuschlag, A.; Bartsch, J.; Glatthaar, M.; Glunz, S. W.

    2014-12-01

    In the context of nickel silicide formation from plated nickel layers for solar cell metallization, there are several open questions regarding contact adhesion and electrical properties. Nanoscale characterization by transmission electron microscopy has been employed to support these investigations. Interfacial oxides and silicide phases were investigated on differently prepared samples by different analytical methods associated with transmission electron microscopy analysis. Processing variations included the pre-treatment of samples before nickel plating, the used plating solution and the thermal budget for the nickel-silicon solid-state reaction. It was shown that interface oxides of only few nm thickness on both silicon and nickel silicide are present on the samples, depending on the chosen process sequence, which have been shown to play an important role in adhesion of nickel on silicide in an earlier publication. From sample pretreatment variations, conclusions about the role of an interfacial oxide in silicide formation and its influence on phase formation were drawn. Such an oxide layer hinders silicide formation except for pinhole sites. This reduces the availability of Ni and causes a silicide with low Ni content to form. Without an interfacial oxide a continuous nickel silicide of greater depth, polycrystalline modification and expected phase according to thermal budget is formed. Information about the nature of silicide growth on typical solar cell surfaces could be obtained from silicide phase and geometric observations, which were supported by FIB tomography. The theory of isotropic NiSi growth and orientation dependent NiSi2 growth was derived. By this, a very well performing low-cost metallization for silicon solar cells has been brought an important step closer to industrial introduction.

  7. stu Black Holes Unveiled

    Directory of Open Access Journals (Sweden)

    Armen Yeranyan

    2008-10-01

    Full Text Available The general solutions of the radial attractor flow equations for extremal black holes, both for non-BPS with non-vanishing central charge Z and for Z = 0, are obtained for the so-called stu model, the minimal rank-3 N = 2 symmetric supergravity in d = 4 space-time dimensions. Comparisons with previous partial results, as well as the fake supergravity (first order formalism and an analysis of the marginal stability of corresponding D-brane configurations, are given.

  8. Noncommutative black holes

    Science.gov (United States)

    Bastos, C.; Bertolami, O.; Dias, N. C.; Prata, J. N.

    2010-04-01

    One considers phase-space noncommutativity in the context of a Kantowski-Sachs cosmological model to study the interior of a Schwarzschild black hole. It is shown that the potential function of the corresponding quantum cosmology problem has a local minimum. One deduces the thermodynamics and show that the Hawking temperature and entropy exhibit an explicit dependence on the momentum noncommutativity parameter, η. Furthermore, the t = r = 0 singularity is analysed in the noncommutative regime and it is shown that the wave function vanishes in this limit.

  9. Noncommutative black holes

    Energy Technology Data Exchange (ETDEWEB)

    Bastos, C; Bertolami, O [Departamento de Fisica, Instituto Superior Tecnico, Avenida Rovisco Pais 1, 1049-001 Lisboa (Portugal); Dias, N C; Prata, J N, E-mail: cbastos@fisica.ist.utl.p, E-mail: orfeu@cosmos.ist.utl.p, E-mail: ncdias@mail.telepac.p, E-mail: joao.prata@mail.telepac.p [Departamento de Matematica, Universidade Lusofona de Humanidades e Tecnologias, Avenida Campo Grande, 376, 1749-024 Lisboa (Portugal)

    2010-04-01

    One considers phase-space noncommutativity in the context of a Kantowski-Sachs cosmological model to study the interior of a Schwarzschild black hole. It is shown that the potential function of the corresponding quantum cosmology problem has a local minimum. One deduces the thermodynamics and show that the Hawking temperature and entropy exhibit an explicit dependence on the momentum noncommutativity parameter, {eta}. Furthermore, the t = r = 0 singularity is analysed in the noncommutative regime and it is shown that the wave function vanishes in this limit.

  10. Noncommutative black holes

    International Nuclear Information System (INIS)

    One considers phase-space noncommutativity in the context of a Kantowski-Sachs cosmological model to study the interior of a Schwarzschild black hole. It is shown that the potential function of the corresponding quantum cosmology problem has a local minimum. One deduces the thermodynamics and show that the Hawking temperature and entropy exhibit an explicit dependence on the momentum noncommutativity parameter, η. Furthermore, the t = r = 0 singularity is analysed in the noncommutative regime and it is shown that the wave function vanishes in this limit.

  11. Thermal BEC Black Holes

    Directory of Open Access Journals (Sweden)

    Roberto Casadio

    2015-10-01

    Full Text Available We review some features of Bose–Einstein condensate (BEC models of black holes obtained by means of the horizon wave function formalism. We consider the Klein–Gordon equation for a toy graviton field coupled to a static matter current in a spherically-symmetric setup. The classical field reproduces the Newtonian potential generated by the matter source, while the corresponding quantum state is given by a coherent superposition of scalar modes with a continuous occupation number. An attractive self-interaction is needed for bound states to form, the case in which one finds that (approximately one mode is allowed, and the system of N bosons can be self-confined in a volume of the size of the Schwarzschild radius. The horizon wave function formalism is then used to show that the radius of such a system corresponds to a proper horizon. The uncertainty in the size of the horizon is related to the typical energy of Hawking modes: it decreases with the increasing of the black hole mass (larger number of gravitons, resulting in agreement with the semiclassical calculations and which does not hold for a single very massive particle. The spectrum of these systems has two components: a discrete ground state of energy m (the bosons forming the black hole and a continuous spectrum with energy ω > m (representing the Hawking radiation and modeled with a Planckian distribution at the expected Hawking temperature. Assuming the main effect of the internal scatterings is the Hawking radiation, the N-particle state can be collectively described by a single-particle wave-function given by a superposition of a total ground state with energy M = Nm and Entropy 2015, 17 6894 a Planckian distribution for E > M at the same Hawking temperature. This can be used to compute the partition function and to find the usual area law for the entropy, with a logarithmic correction related to the Hawking component. The backreaction of modes with ω > m is also shown to reduce

  12. Black luminescent silicon

    Energy Technology Data Exchange (ETDEWEB)

    Pezoldt, Joerg [FG Nanotechnologie, Institut fuer Mikro- und Nanotechnologie, TU Ilmenau, Postfach 100565, 98684 Ilmenau (Germany); Kups, Thomas [FG Werkstoffe der Elektrotechnik, Institut fuer Mikro- und Nanotechnologien, TU Ilmenau, Postfach 1005765, 98684 Ilmenau (Germany); Stubenrauch, Mike [FG Mikromechanische Systeme, Institut fuer Mikro- und Nanotechnologien, TU Ilmenau, Postfach 1005765, 98684 Ilmenau (Germany); Fischer, Michael [FG Elektroniktechnologie, Institut fuer Mikro- und Nanotechnologien, TU Ilmenau, Postfach 1005765, 98684 Ilmenau (Germany)

    2011-03-15

    Black silicon is a fascinating multipurpose modification of bulk silicon which can be fabricated in a selforganized structure formation process during dry etching of bare silicon wafer leading to the formation of a high density of silicon needles. The smallest dimension of the tips approaches values between 1 and 2 nm. The silicon nanostructure exhibits an extremely low diffuse reflectivity. The nanosized tips and their coating with fluorine doped nonstoichiometric silicon dioxide are responsible for cathodoluminescence in the blue-green and red regions of the visible spectra (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  13. Holographic Black Hole Chemistry

    CERN Document Server

    Karch, Andreas

    2015-01-01

    Thermodynamic quantities associated with black holes in Anti-de Sitter space obey an interesting identity when the cosmological constant is included as one of the dynamical variables, the generalized Smarr relation. We show that this relation can easily be understood from the point of view of the dual holographic field theory. It amounts to the simple statement that the extensive thermodynamic quantities of a large $N$ gauge theory only depend on the number of colors, $N$, via an overall factor of $N^2$.

  14. Black Holes, Black Swans, Black Magic: the Emerging Arts of Project Execution

    OpenAIRE

    Prieto, Bob

    2013-01-01

    Fluor Corporation executive to give Vecellio LectureBlacksburg, VA , September 16, 2013 Virginia Tech College of Engineering Bob Prieto, senior vice president, Fluor Corporation, will present the 2013 Vecellio Distinguished Lecture, titled “Black Holes, Black Swans, Black Magic: the Emerging Arts of Project Execution,” on Friday, Oct. 11 at 4 p.m. in Torgersen 2150. His talk will provide a whirlwind tour of some of the growing challenges in construction project execution and some of the emerg...

  15. Polymer supported nickel complex: Synthesis, structure and catalytic application

    Indian Academy of Sciences (India)

    Alekha Kumar Sutar; Tungabidya Maharana; Yasobanta Das; Prasanta Rath

    2014-11-01

    In the present investigation, a new synthetic route for a novel recyclable free [3-MOBdMBn-Ni] and polystyrene-anchored [P-3-MOBdMBn-Ni] nickel complexes is presented. The free and polymer-anchored metal complexes were synthesized by the reaction of nickel (II) with one molar equivalent of unsupported N N′-bis (2-Hydroxy-3-methoxybenzaldehyde) 4-Methylbenzene-1,2-diamine (3-MOBdMBn) or polymersupported (P-3-MOBdMBn) Schiff-base ligand in methanol under nitrogen atmosphere. The advantages of these polymer-supported catalysts are the low cost of catalyst and recyclability up to six times, due to easy availability of materials and simple synthetic route. The higher efficiency of complexation of nickel on the polymer-anchored 3-MOBdMBn Schiff base than the unsupported analogue is another advantage of this catalyst system. The structural study reveals that nickel(II) complex of 3-MOBdMBn is square planar in geometry. The catalytic activity of nickel complex towards the oxidation of phenol was investigated in the presence of hydrogen peroxide. Experimental results indicate that the reactivity of P-3-MOBdMBn-Ni was dramatically affected by the polymer support compared to free 3-MOBdMBn-Ni. The rates of oxidation (R) for unsupported and supported catalysts are 1.37 × 10-6 mole dm-3 s-1 and 2.33 × 10-6 mole dm-3 s-1 respectively.

  16. Nanoparticles reduce nickel allergy by capturing metal ions

    Science.gov (United States)

    Vemula, Praveen Kumar; Anderson, R. Rox; Karp, Jeffrey M.

    2011-05-01

    Approximately 10% of the population in the USA suffer from nickel allergy, and many are unable to wear jewellery or handle coins and other objects that contain nickel. Many agents have been developed to reduce the penetration of nickel through skin, but few formulations are safe and effective. Here, we show that applying a thin layer of glycerine emollient containing nanoparticles of either calcium carbonate or calcium phosphate on an isolated piece of pig skin (in vitro) and on the skin of mice (in vivo) prevents the penetration of nickel ions into the skin. The nanoparticles capture nickel ions by cation exchange, and remain on the surface of the skin, allowing them to be removed by simple washing with water. Approximately 11-fold fewer nanoparticles by mass are required to achieve the same efficacy as the chelating agent ethylenediamine tetraacetic acid. Using nanoparticles with diameters smaller than 500 nm in topical creams may be an effective way to limit the exposure to metal ions that can cause skin irritation.

  17. Improvement of solvents for chemical decontamination: nickel ferrites removal

    International Nuclear Information System (INIS)

    Carboxylic acids are usually included in commercial solvents for the chemical cleaning and decontamination of metal surfaces from the oxide layers grown and/or deposited from high temperature water by corrosive process. In particular oxalic acid is included in second path of AP-Citrox method. However, in some cases, their use shows low efficiency. This fact is attributed to the special passivity of the mixed oxides as nickel ferrites. This work reports a kinetic study of dissolution of a synthetic nickel ferrite (NiFe2O4) confronted with simple oxides (NiO and Fe2O3) in mineral acids and oxalic acid. The dissolution factor and reaction rate were determined in several conditions (reactive concentrations, pH and added ferrous ions). Experimental data of dissolution (with and without Fe(II) added) show a congruent kinetic regime. Pure nickel oxide (NiO) is rather resistant to the attack by oxalic acid solutions, and ferrous ions do not accelerate dissolution. In fact, nickel oxide dissolves better by oxidative attack that takes advantage of the higher lability of Ni3+. It may be concluded that oxalic acid operates to dissolve iron, and the ensuing disruption of the solid framework accelerates the release of nickel. Our results point to use more reactive solvents in iron from mixed oxides and to the possibility of using one stage decontamination method. (author)

  18. Forming limits of nickel coating on right region

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The forming limits of nickel coating on the right region were studied, so as to direct the preparation of the material and help the production of workpieces. The electrodeposited nickel coating was prepared on steel substrate to form advanced structures,and its plastic instability was investigated by the Swift Plastic Instability Theory. By using the compound law for laminated sheet metals, explicit equations for the calculation of the instable eigen values were deduced. The forming limit diagrams of the nickel coating on the right region were plotted. It is exhibited that the forming limit of the coating sheet is between the forming limits of the individual nickel coating and steel substrate. The forming limit of the nickel coating is not so good as that of the steel substrate, and the forming limit strain of the coating sheet tends to diminish with the increase of thickness of the coating. The greater the normal anisotropic coefficient of the materials is, the better the forming limit is.

  19. Environmentally friendly process for nickel electroplating of ABS

    Science.gov (United States)

    Bazzaoui, M.; Martins, J. I.; Bazzaoui, E. A.; Albourine, A.

    2012-08-01

    Nickel electroplating of acrylonitrile butadiene styrene (ABS) plastic has been achieved successfully without any chromium or palladium pretreatment. Once the ABS is coated with polypyrrole (PPy), the sample may be electroplated. The process is fast, economic and involves three stages. Firstly, chemical deposition of PPy on ABS, secondly, copper deposition and finally nickel electroplating. A homogenous and adherent PPy has been synthesized chemically on ABS plate by using pyrrole as monomer and iron (III) chloride as oxidant. Copper and nickel were deposited galvanostatically from industrial plating baths. The metallic coatings were homogeneous and the adherence was estimated at 100%. The thickness of copper and nickel depend on the electrolysis time. As the current density increases, the Cu and Ni thickness raises. This result was confirmed from SEM characterization and RX map. The Ni coating is characterized by a globular structure with globules of different sizes. Energy dispersive X-ray spectroscopy (EDS) analysis shows the presence of Ni with some amount of carbon and oxygen due to the nickel oxides and contaminant from the bath solution.

  20. Nickel Nanoparticles Exposure and Reproductive Toxicity in Healthy Adult Rats

    Directory of Open Access Journals (Sweden)

    Lu Kong

    2014-11-01

    Full Text Available Nickel is associated with reproductive toxicity. However, the reproductive toxicity of nickel nanoparticles (Ni NPs is unclear. Our goal was to determine the association between nickel nanoparticle exposure and reproductive toxicity. According to the one-generation reproductive toxicity standard, rats were exposed to nickel nanoparticles by gavage and we selected indicators including sex hormone levels, sperm motility, histopathology, and reproductive outcome etc. Experimental results showed nickel nanoparticles increased follicle stimulating hormone (FSH and luteinizing hormone (LH, and lowered etradiol (E2 serum levels at a dose of 15 and 45 mg/kg in female rats. Ovarian lymphocytosis, vascular dilatation and congestion, inflammatory cell infiltration, and increase in apoptotic cells were found in ovary tissues in exposure groups. For male rats, the weights decreased gradually, the ratio of epididymis weight over body weight increased, the motility of rat sperm changed, and the levels of FSH and testosterone (T diminished. Pathological results showed the shedding of epithelial cells of raw seminiferous tubule, disordered arrangement of cells in the tube, and the appearance of cell apoptosis and death in the exposure group. At the same time, Ni NPs resulted in a change of the reproductive index and the offspring development of rats. Further research is needed to elucidate exposure to human populations and mechanism of actions.