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Sample records for replicated nickel optics

  1. Developments for Nickel Electroformed X-Ray Optics

    Science.gov (United States)

    Ramsey, B.; Engelhaupt, D.; Gubarev, M.; O'Dell, S.; Speegle, C.; Weisskopf, M.

    2008-01-01

    This slide presentation reviews the developments at Marshall Space Flight Center in fabricating Electroformed Nickel X-ray Optical devices. Missions that are using the mandrels created using the described process are reviewed, and improvements in the process of creating better quality mandrels are also reviewed. One of the processes, Electrochemically-Enhanced Mechanical Polishing (EEMP), is described. The Alignment and mounting system for full-shell replicated X-Ray Optics is shown, and the selective deposition process is also shown.

  2. Technology Development for Nickel X-Ray Optics Enhancement

    Science.gov (United States)

    Bubarev, Mikhail; Ramsey, Brian; Engelhaupt, Darell

    2008-01-01

    We are developing grazing-incidence x-ray optics for high-energy astrophysics using the electroform-nickel replication process. In this process, mirror shells are fabricated by replication off super-polished cylindrical mandrels. The mirrors fabricated using this process have a demonstrated optical performance at the level of 11-12 arc seconds resolution (HPD) for 30 keV x rays. Future missions demand ever higher angular resolutions and this places stringent requirements on the quality of the mandrels, the precision of the metrology, and the mounting and alignment of the mirror shells in their housings. A progress report on recent technology developments in all these areas will be presented along with a discussion on possible post fabrication, in-situ improvement of the x-ray mirrors quality.

  3. 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.

  4. Challenges in high accuracy surface replication for micro optics and micro fluidics manufacture

    DEFF Research Database (Denmark)

    Tosello, Guido; Hansen, Hans Nørgaard; Calaon, Matteo;

    2014-01-01

    by replication technologies such as nickel electroplating. All replication steps are enabled by a high precision master and high reproduction fidelity to ensure that the functionalities associated with the design are transferred to the final component. Engineered surface micro structures can be either......Patterning the surface of polymer components with microstructured geometries is employed in optical and microfluidic applications. Mass fabrication of polymer micro structured products is enabled by replication technologies such as injection moulding. Micro structured tools are also produced...... distributed, e.g., to create an optical pattern, or discretised, e.g., as micro channels for fluids manipulation. Key aspects of two process chains based on replication technologies for both types of micro structures are investigated: lateral replication fidelity, dimensional control at micro scale, edge...

  5. Optical tweezers reveal how proteins alter replication

    Science.gov (United States)

    Chaurasiya, Kathy

    Single molecule force spectroscopy is a powerful method that explores the DNA interaction properties of proteins involved in a wide range of fundamental biological processes such as DNA replication, transcription, and repair. We use optical tweezers to capture and stretch a single DNA molecule in the presence of proteins that bind DNA and alter its mechanical properties. We quantitatively characterize the DNA binding mechanisms of proteins in order to provide a detailed understanding of their function. In this work, we focus on proteins involved in replication of Escherichia coli (E. coli ), endogenous eukaryotic retrotransposons Ty3 and LINE-1, and human immunodeficiency virus (HIV). DNA polymerases replicate the entire genome of the cell, and bind both double-stranded DNA (dsDNA) and single-stranded DNA (ssDNA) during DNA replication. The replicative DNA polymerase in the widely-studied model system E. coli is the DNA polymerase III subunit alpha (DNA pol III alpha). We use optical tweezers to determine that UmuD, a protein that regulates bacterial mutagenesis through its interactions with DNA polymerases, specifically disrupts alpha binding to ssDNA. This suggests that UmuD removes alpha from its ssDNA template to allow DNA repair proteins access to the damaged DNA, and to facilitate exchange of the replicative polymerase for an error-prone translesion synthesis (TLS) polymerase that inserts nucleotides opposite the lesions, so that bacterial DNA replication may proceed. This work demonstrates a biophysical mechanism by which E. coli cells tolerate DNA damage. Retroviruses and retrotransposons reproduce by copying their RNA genome into the nuclear DNA of their eukaryotic hosts. Retroelements encode proteins called nucleic acid chaperones, which rearrange nucleic acid secondary structure and are therefore required for successful replication. The chaperone activity of these proteins requires strong binding affinity for both single- and double-stranded nucleic

  6. Comments on the paper: 'Optical reflectance, optical refractive index and optical conductivity measurements of nonlinear optics for L-aspartic acid nickel chloride single crystal'

    Science.gov (United States)

    Srinivasan, Bikshandarkoil R.; Naik, Suvidha G.; Dhavskar, Kiran T.

    2016-02-01

    We argue that the 'L-aspartic acid nickel chloride' crystal reported by the authors of the title paper (Optics Communications, 291 (2013) 304-308) is actually the well-known diaqua(L-aspartato)nickel(II) hydrate crystal.

  7. Optical and electrical properties of nickel xanthate thin films

    Indian Academy of Sciences (India)

    İ A Kariper; T Özpozan

    2014-05-01

    Nickel xanthate thin films (NXTF) were successfully deposited by chemical bath deposition, on to amorphous glass substrates, as well as on - and -silicon, indium tin oxide and poly(methyl methacrylate). The structure of the films was analysed by X-ray diffraction (XRD), far-infrared spectrum (FIR), mid-infrared (MIR) spectrum, nuclear magnetic resonance (NMR) and scanning electron microscopy (SEM). These films were investigated from their structural, optical and electrical properties point of view. Uniform distribution of grains was clearly observed from the photographs taken by scanning electron microscope (SEM). The higher transmittance was about 50–60% after optimizing the parameters of deposition time and temperature (4 h, 50 °C). The optical bandgap of the NXTF was graphically estimated as 3.90–3.96 eV. The resistivity of the films was calculated as 62.6–90.7 .cm on commercial glass depending on the film thickness and 62.2–74.5 .cm on the other substrates. The MIR and FIR spectra of the films conformed to the literature and their solid powder forms. The expected peaks of nickel xanthate were observed in NMR analysis on glass. The films were dipped into chloroform as organic solvent and were analysed by NMR.

  8. Magnetic and optical properties of the nickel thin film deposited by GLAD technique

    Directory of Open Access Journals (Sweden)

    Potočnik Jelena M.

    2014-01-01

    Full Text Available In this work, nickel thin film was deposited on glass sample using Glancing Angle Deposition (GLAD technique, to a thickness of 1 μm. Glass sample was positioned 15 degrees with respect to the nickel vapor flux. The nickel thin film was characterized by Atomic Force Microscopy (AFM, Magneto- Optical Kerr effect Microscopy and Spectroscopic Ellipsometry. According to an AFM cross-section imaging, it was found that the nickel thin film has a columnar structure. The values of the coercively, obtained from the magnetic hysteresis loops, were analyzed as a function of the sample rotation in the magnetic field. It was found that the direction of magnetization easy axis lies toward the structure growth. Optical properties of the nickel thin film were studied at the wavelength of 455 nm. From the shape of the refractive index and the extinction coefficient diagrams could be concluded that the nickel thin film has an optical anisotropy.

  9. Optical Properties of Magnetron sputtered Nickel Thin Films

    Science.gov (United States)

    Twagirayezu, Fidele; Geerts, Wilhelmus J.; Cui, Yubo

    2015-03-01

    The study of optical properties of Nickel (Ni) is important, given the pivotal role it plays in the semiconductor and nano-electronics technology. Ni films were made by DC and RF magnetron sputtering in an ATC Orion sputtering system of AJA on various substrates. The optical properties were studied ex situ by variable angle spectroscopic (220-1000 nm) ellipsometry at room temperature. The data were modeled and analyzed using the Woollam CompleteEase Software fitting ellipsometric and transmission data. Films sputtered at low pressure have optical properties similar to that of Palik. Films sputtered at higher pressure however have a lower refraction index and extinction coefficient. It is expected from our results that the density of the sputtered films can be determined from the ellipsometric quantities. Our experiments also revealed that Ni is susceptible to a slow oxidation changing its optical properties over the course of several weeks. The optical properties of the native oxide differ from those of reactive sputtered NiO similar as found by. Furthermore the oxidation process of our samples is characterized by at least two different time constants.

  10. Electrical and optical properties of nickel ferrite/polyaniline nanocomposite

    Directory of Open Access Journals (Sweden)

    M. Khairy

    2015-07-01

    Full Text Available Polyaniline–NiFe2O4 nanocomposites (PANI–NiFe2O4 with different contents of NiFe2O4 (2.5, 5 and 50 wt% were prepared via in situ chemical oxidation polymerization, while the nanoparticles nickel ferrite were synthesized by sol–gel method. The prepared samples were characterized using some techniques such as Fourier transforms infrared (FTIR, X-ray diffraction (XRD, scanning electron microscopy (SEM and thermogravimetric analysis (TGA. Moreover, the electrical conductivity and optical properties of the nanocomposites were investigated. Pure (PANI and the composites containing 2.5 and 5 wt% NiFe2O4 showed amorphous structures, while the one with 50 wt% NiFe2O4 showed a spinel crystalline structure. The SEM images of the composites showed different aggregations for the different nickel ferrite contents. FTIR spectra revealed to the formation of some interactions between the PANI macromolecule and the NiFe2O4 nanoparticles, while the thermal analyses indicated an increase in the composites stability for samples with higher NiFe2O4 nanoparticles contents. The electrical conductivity of PANI–NiFe2O4 nanocomposite was found to increase with the rise in NiFe2O4 nanoparticle content, probably due to the polaron/bipolaron formation. The optical absorption experiments illustrate direct transition with an energy band gap of Eg = 1.0 for PANI–NiFe2O4 nanocomposite.

  11. Nickel

    Science.gov (United States)

    The agricultural significance of nickel (Ni) is becoming increasingly apparent; yet, relative few farmers, growers, specialists or researchers know much about its function in crops, nor symptoms of deficiency or toxicity. The body of knowledge is reviewed regarding Ni’s background, uptake, transloc...

  12. Replication of self-centering optical fiber alignment structures using hot embossing

    Science.gov (United States)

    Ebraert, Evert; Wissmann, Markus; Barié, Nicole; Guttmann, Markus; Schneider, Marc; Kolew, Alexander; Worgull, Matthias; Beri, Stefano; Watté, Jan; Thienpont, Hugo; Van Erps, Jürgen

    2016-04-01

    With the demand for broadband connectivity on the rise due to various services like video-on-demand and cloud computing becoming more popular, the need for better connectivity infrastructure is high. The only future- proof option to supply this infrastructure is to deploy "fiber to the home" (FTTH) networks. One of the main difficulties with the deployment of FTTH is the vast amount of single-mode fiber (SMF) connections that need to be made. Hence there is a strong need for components which enable high performance, robust and easy-to- use SMF connectors. Since large-scale deployment is the goal, these components should be mass-producible at low cost. We discuss a rapid prototyping process on the basis of hot embossing replication of a self-centering alignment system (SCAS) based on three micro-springs, which can position a SMF independently of its diameter. This is beneficial since there is a fabrication tolerance of up to +/-1 μm on a standard G.652 SMF's diameter that can lead to losses if the outer diameter is used as a reference for alignment. The SCAS is first prototyped with deep proton writing (DPW) in polymethylmethacrylate (PMMA) after which it is glued to a copper substrate with an adhesive. Using an electroforming process, a nickel block is grown over the PMMA prototype followed by mechanical finishing to fabricate a structured nickel mould insert. Even though the mould insert shows non- ideal and rounded features it is used to create PMMA replicas of the SCAS by means of hot embossing. The SCAS possesses a central opening in which a bare SMF can be clamped, which is designed with a diameter of 121 μm. PMMA replicas are dimensionally characterized using a multisensor coordinate measurement machine and show a central opening diameter of 128.3 +/- 2.8 μm. This should be compared to the central opening diameter of the DPW prototype used for mould formation which was measured to be 120.5 μm. This shows that the electroforming and subsequent replication

  13. Optical and structural characterization of nickel selenide nanoparticles synthesized by simple methods

    Science.gov (United States)

    Moloto, N.; Moloto, M. J.; Coville, N. J.; Sinha Ray, S.

    2009-07-01

    A series of nickel selenide (NiSe 2, NiSe and Ni 3Se 4) nanoparticles have been synthesized by three different methods, i.e. the single-source precursor (method 1), the thermolysis of trioctylphosphine selenide (TOPSe) and nickel chloride in hexadecylamine (method 2) as well as the reaction of nickel chloride and selenium using sodium borohydride as a reducing agent in methanol and in water (method 3). The optical properties of nickel selenide synthesized from all the methods showed good nanometric characteristics with an observed blue-shift in absorption band-edge from bulk nickel selenide. The structural characteristics varied with the methods employed, with method 1 producing 10 nm spherical NiSe 2 particles, method 2 star-shaped NiSe particles, while method 3 produced hexagonal NiSe nanoparticles in methanol and rod-shaped Ni 3Se 4 particles in water.

  14. Direct diamond turning of steel molds for optical replication

    Science.gov (United States)

    Klocke, Fritz; Dambon, Olaf; Bulla, Benjamin; Heselhaus, Michael

    2009-05-01

    In this paper the most recent investigations in ultrasonic assisted diamond machining of hardened steel at the Fraunhofer IPT is presented. The goal of this technology is to unify the outrageous specifications of diamond machining process with steel material. The focus lies on the kinematic influence of the discrete frequencies 40 kHz and 60 kHz. Special interest is given to the reachable surface roughness depending on process parameters. The machined steel (1.2083, X40Cr14, STAVAX ESU) is a common mold die material for optical replication processes.Results of the accomplished investigations show the potential of the ultrasonic assisted process and recent developments. By increasing the frequency from 40 kHz to 60 kHz the overall process stability is increased. This makes the process less vulnerable towards feed rate variation or towards the variation of machined material hardness. Furthermore no tool wear is detected at high material removal rates or high cutting distances during component machining.

  15. Optical and Structural Characterization of Nickel Coatings for Solar Collector Receivers

    Directory of Open Access Journals (Sweden)

    Stefano Pratesi

    2014-01-01

    Full Text Available The development of spectrally selective materials is gaining an increasing role in solar thermal technology. The ideal spectrally selective solar absorber requires high absorbance at the solar spectrum wavelengths and low emittance at the wavelengths of thermal spectrum. Selective coating represents a promising route to improve the receiver efficiency for parabolic trough collectors (PTCs. In this work, we describe an intermediate step in the fabrication of black-chrome based solar absorbers, namely, the fabrication and characterization of nickel coatings on stainless steel substrates. Microstructural characteristics of nickel surfaces are known to favorably affect further black chrome deposition. Moreover, the high reflectivity of nickel in the thermal infrared wavelength region can be advantageously exploited for reducing thermal emission losses. Thus, this report investigates structural features and optical properties of the nickel surfaces, correlating them to coating thickness and deposition process, in the perspective to assess optimal conditions for solar absorber applications.

  16. Clad modified optical fiber gas sensors based on nanocrystalline nickel oxide embedded coatings

    Science.gov (United States)

    Yamini, K.; Renganathan, B.; Ganesan, A. R.; Prakash, T.

    2017-07-01

    A clad modified optical fiber gas sensor for sensing volatile organic compound vapours (VOCs) such as formaldehyde (HCHO), ammonia (NH3), ethanol (C2H5OH) and methanol (CH3OH) up to 500 ppm was studied using nanocrystalline nickel oxide embedded coatings. Prior to the measurements, nickel oxide in two different crystallite sizes such as 24 nm and 76 nm was synthesized by calcination of reverse precipitated nickel hydroxide subsequently at 450 °C and 900 °C for 30 min. Then, samples physical properties were characterized using X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM) and high resolution transmission electron microscopy (HRTEM). Our gas sensing measurement concludes that the lower crystallite size (24 nm) nickel oxide nanocrystals exhibits superior performance to formaldehyde and ethanol vapours as compared with other two VOCs, the observed experimental results were discussed in detail.

  17. Optical and Thermal Properties of Nickel-Azo Dyes for Digital Versatile Disc-Recordable

    Institute of Scientific and Technical Information of China (English)

    魏斌; 吴谊群; 顾冬红; 干福熹

    2003-01-01

    We investigate the absorption spectra, optical constants and thermal decomposition as well as red-light (650 nm)static recording properties of three novel nickel-azo dye filrns based on 4-methylthiazole, benzothiazole and 6-methylbenzothiazole. Particularly, we obtain the nickel-azo complex film based on 4-methylthiazole, peaking at 562nm and 613nm, with higher refractive index (n = 2.46) and lower extinction coefficient (k = 0.18) at the wavelength 650nm and a sharp threshold of thermal decomposition at 330℃. The results of the static optical recording test of this dye film indicate that high reflectivity contrast of 51% can be observed at a laser writing power of 5.9mW and pulse width of 350ns. These results imply that the nickel-azo complex based on 4-methylthiazole is a promising candidate for a recording medium of digital versatile disc-recordable.

  18. Enhanced optical absorbance and fabrication of periodic arrays on nickel surface using nanosecond laser

    Science.gov (United States)

    Fu, Jinxiang; Liang, Hao; Zhang, Jingyuan; Wang, Yibo; Liu, Yannan; Zhang, Zhiyan; Lin, Xuechun

    2017-04-01

    A hundred-nanosecond pulsed laser was employed to structure the nickel surface. The effects of laser spatial filling interval and laser scanning speed on the optical absorbance capacity and morphologies on the nickel surface were experimentally investigated. The black nickel surface covered with dense micro/nanostructured broccoli-like clusters with strong light trapping capacity ranging from the UV to the near IR was produced at a high laser scanning speed up to v=100 mm/s. The absorbance of the black nickel is as high as 98% in the UV range of 200-400 nm, more than 97% in the visible spectrum, ranging from 400 to 800 nm, and over 90% in the IR between 800 and 2000 nm. In addition, when the nickel surface was irradiated in two-dimensional crossing scans by laser with different processing parameters, self-organized and shape-controllable structures of three-dimensional (3D) periodic arrays can be fabricated. Compared with ultrafast laser systems previously used for such processing, the nanosecond fiber laser used in this work is more cost-effective, compact and allows higher processing rates. This nickel surface structured technique may be applicable in optoelectronics, batteries industry, solar/wave absorbers, and wettability materials.

  19. Advanced Optical Metrology for XRAY Replication Mandrels and Mirrors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced x-ray observatories such as IXO and GenX will require thousands of thin shell mirror segments produced by replication using convex mandrels. Quality and...

  20. Replication of the Apparent Excess Heat Effect in a Light Water-Potassium Carbonate-Nickel Electrolytic Cell

    Science.gov (United States)

    Niedra, Janis M.; Myers, Ira T.; Fralick, Gustave C.; Baldwin, Richard S.

    1996-01-01

    Replication of experiments claiming to demonstrate excess heat production in light water-Ni-K2CO3 electrolytic cells was found to produce an apparent excess heat of 11 W maximum, for 60 W electrical power into the cell. Power gains range from 1.06 to 1.68. The cell was operated at four different dc current levels plus one pulsed current run at 1 Hz, 10% duty cycle. The 28 liter cell used in these verification tests was on loan from a private corporation whose own tests with similar cells are documented to produce 50 W steady excess heat for a continuous period exceeding hundreds of days. The apparent excess heat can not be readily explained either in terms of nonlinearity of the cell's thermal conductance at a low temperature differential or by thermoelectric heat pumping. However, the present data do admit efficient recombination of dissolved hydrogen-oxygen as an ordinary explanation. Calorimetry methods and heat balance calculations for the verification tests are described. Considering the large magnitude of benefit if this effect is found to be a genuine new energy source, a more thorough investigation of evolved heat in the nickel-hydrogen system in both electrolytic and gaseous loading cells remains warranted.

  1. Optical reflectance, optical refractive index and optical conductivity measurements of nonlinear optics for L-aspartic acid nickel chloride single crystal

    Science.gov (United States)

    Anbazhagan, G.; Joseph, P. S.; Shankar, G.

    2013-03-01

    Single crystals of L-aspartic acid nickel chloride (LANC) were grown by the slow evaporation technique at room temperature. The grown crystals were subjected to Powder X-ray diffraction studies to confirm the crystal structure. The modes of vibration of different molecular groups present in LANC have been identified by FTIR spectral analysis. Optical transferency of the grown crystal was investigated by UV-Vis-NIR spectrum. The lower optical cut off wavelength for this crystal is observed at 240 nm and energy band gap 5.179 eV. The optical reflectance and optical refractive index studies have been carried out in this crystal. Finally, the optical conductivity and electrical conductivity studies have been carried out on LANC single crystal.

  2. Shell Separation for Mirror Replication

    Science.gov (United States)

    1999-01-01

    NASA's Space Optics Manufacturing Center has been working to expand our view of the universe via sophisticated new telescopes. The Optics Center's goal is to develop low-cost, advanced space optics technologies for the NASA program in the 21st century - including the long-term goal of imaging Earth-like planets in distant solar systems. To reduce the cost of mirror fabrication, Marshall Space Flight Center (MSFC) has developed replication techniques, the machinery, and materials to replicate electro-formed nickel mirrors. Optics replication uses reusable forms, called mandrels, to make telescope mirrors ready for final finishing. MSFC optical physicist Bill Jones monitors a device used to chill a mandrel, causing it to shrink and separate from the telescope mirror without deforming the mirror's precisely curved surface.

  3. Effect of thickness on optical properties of nickel vertical posts deposited by GLAD technique

    Science.gov (United States)

    Potočnik, J.; Nenadović, M.; Bundaleski, N.; Popović, M.; Rakočević, Z.

    2016-12-01

    Nickel (Ni) thin films of different thicknesses (25 nm to 150 nm) were deposited on glass substrates using Glancing Angle Deposition technique. Characterization of obtained Ni films was performed by scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, spectroscopic ellipsometry and by four-point probe method. Variations in optical parameters with thickness correlated with structural, chemical and electrical properties of nanostructured nickel thin films were studied. The results showed that deposit is porous and consists of nano-scaled columns, which grow perpendicular to the substrate. It was found that the size of the columns and the surface roughness change with film thickness. Spectroscopic ellipsometry revealed that the refractive index and extinction coefficient varied with thickness, which can be correlated with changes in microstructure of Ni films. Additionally, the relationship between the film microstructure and its resistivity was also analyzed. It was found that the variations in Ni films resistivity could be attributed to the changes in the width of the columns. The increasing of layer thickness leads to overall decrease of optical resistivity of nickel thin films.

  4. Synthesis and Characterization of Optically Active Fractal Seed Mediated Silver Nickel Bimetallic Nanoparticles

    Directory of Open Access Journals (Sweden)

    Joseph Adeyemi Adekoya

    2014-01-01

    Full Text Available The synthesis of new seed mediated AgNi allied bimetallic nanocomposites was successfully carried out by the successive reduction of the metal ions in diethylene glycol, ethylene glycol, glycerol, and pentaerythritol solutions, with concomitant precipitation of Ag/Ni bimetal sols. The optical measurement revealed the existence of distinct band edge with surface plasmon resonance (SPR in the region of 400–425 nm and excitonic emission with maximum peak at 382 nm which were reminiscent of cluster-in-cluster surface enriched bimetallic silver-nickel sols. The morphological characterization by transmission electron microscopy, high resolution transmission electron microscopy, and X-ray diffraction analyses complimented by surface scan using X-ray photoelectron spectroscopy strongly supported the formation of intimately alloyed face-centered silver/nickel nanoclusters.

  5. 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.

  6. Replication of optical microlens arrays using photoresist coated molds

    DEFF Research Database (Denmark)

    Chakrabarti, Maumita; Dam-Hansen, Carsten; Stubager, Jørgen

    2016-01-01

    A cost reduced method of producing injection molding tools is reported and demonstrated for the fabrication of optical microlens arrays. A standard computer-numerical-control (CNC) milling machine was used to make a rough mold in steel. Surface treatment of the steel mold by spray coating...... the light engine. Polymer injection molded microlens arrays were produced from both the rough and coated molds and have been characterized for lenslet parameters, surface quality, light scattering, and acceptance angle. The surface roughness (Ra) is improved approximately by a factor of two after...... the coating process and the light scattering is reduced so that the molded microlens array can be used for the color mixing application. The measured accepted angle of the microlens array is 40° which is in agreement with simulations....

  7. Effect of electron beam irradiation on the structure and optical properties of nickel oxide nanocubes

    Indian Academy of Sciences (India)

    P A Sheena; K P Priyanka; N Aloysius Sabu; S Ganesh; Thomas Varghese

    2015-08-01

    This work reports the effect of electron beam (EB) irradiation on the structure and optical properties of nanocrystalline nickel oxide (NiO) cubes. NiO nanocubes were synthesized by the chemical precipitation method. The characterization was carried out by employing analytical techniques like X-ray diffraction, transmission electron microscopy, UV–visible and photoluminescence (PL) spectroscopy. The present investigation found that non-stoichiometry, defects and particle size variation caused by EB irradiation have a great influence on optical band gap, blue shift and band modification of absorption and PL spectra. Moreover, EB irradiation can result enhanced optical absorption performance and photo-activity in NiO nanocubes for optoelectronics and photo-catalytic applications. The study of International Commission on Illumination chromaticity diagram indicates that NiO can be developed as a suitable phosphor material for the application in near ultraviolet excited colour LEDs.

  8. Growth, spectral, optical and thermal characterization of new metallorganic crystal--bisthiourea nickel chloride.

    Science.gov (United States)

    Ramachandraraja, C; Joseph, A Antony; Sundararajan, R S; Shankar, V Siva; Murugakoothan, P

    2009-12-01

    The novel nonlinear optical single crystal of bisthiourea nickel chloride (BTNC) was grown successfully by slow evaporation technique using water as solvent. The lattice parameters of the grown crystal have been determined by X-ray diffraction studies. Vibrational spectra were recorded to determine the symmetries of molecular vibrations. Presence of various functional groups of BTNC was identified through FTIR and Raman spectroscopic analyses. Optical absorbance spectrum recorded in the wavelength range of UV-vis-NIR revealed that this crystal has good optical transparency in the range 200-2000 nm. The second harmonic generation test of BTNC revealed the nonlinear nature of the crystal. The BTNC crystal was analyzed by differential thermal and thermo gravimetric analysis (DTA-TGA) to obtain its thermal stability.

  9. Growth, spectral, optical and thermal characterization of new metallorganic crystal—Bisthiourea nickel chloride

    Science.gov (United States)

    Ramachandraraja, C.; Joseph, A. Antony; Sundararajan, R. S.; Shankar, V. Siva; Murugakoothan, P.

    2009-12-01

    The novel nonlinear optical single crystal of bisthiourea nickel chloride (BTNC) was grown successfully by slow evaporation technique using water as solvent. The lattice parameters of the grown crystal have been determined by X-ray diffraction studies. Vibrational spectra were recorded to determine the symmetries of molecular vibrations. Presence of various functional groups of BTNC was identified through FTIR and Raman spectroscopic analyses. Optical absorbance spectrum recorded in the wavelength range of UV-vis-NIR revealed that this crystal has good optical transparency in the range 200-2000 nm. The second harmonic generation test of BTNC revealed the nonlinear nature of the crystal. The BTNC crystal was analyzed by differential thermal and thermo gravimetric analysis (DTA-TGA) to obtain its thermal stability.

  10. Synthesis and aggregation study of optically active tetra--[()-2-octanyloxy]-substituted copper and nickel phthalocyanines

    Indian Academy of Sciences (India)

    Fang-Di Cong; Gui Gao; Jian-Xin Li; Guo-Qing Huang; Zhen Wei; Feng-Yang Yu; Xi-Guang Du; Ke-Zhi Xing

    2010-11-01

    The optically active tetra--[()-2-octanyloxy]-substituted copper and nickel phthalocyanines were synthesized via a two-step route with 4-nitro-phthalonitrile and ()-2-octanol as the starting materials. Both compounds are fully characterized by MS, 1H NMR, UV-Vis, IR, CD and elemental analysis, and soluble in common organic solvents except methanol. The results showed that they were dispersed into single molecules in chloroform and dichloromethane, but prone to congregate into H-type aggregates in ethanol and diethyl ether. They assembled to H-type aggregates with left-handed helix when deposited as thin films.

  11. Optical and Electrochromic Properties of E-Beam Evaporated Nickel Oxide Thin Film

    Directory of Open Access Journals (Sweden)

    K.J. Patel

    2011-01-01

    Full Text Available Nickel oxide (NiO thin films were deposited by e-beam evaporation on glass and ITO coated glass substrates initially held at room temperature without post-heat treatments. The structural and optical properties were investigated using glancing incident X-ray diffractometer (GIXRD and spectrophotometer. The electrochromic (EC behavior of NiO thin film was investigated using electrochemical technique viz. cyclic voltammetry, constant current measurement, and chronoamperometry in 1 M KOH electrolyte. The transmittance modulation and switching time with different operating voltage were also studied.

  12. Sol-gel replicated optics made from single point diamond turned masters exhibit fractal surface roughness

    Energy Technology Data Exchange (ETDEWEB)

    Bernacki, B.E.; Miller, A.C. Jr.; Evans, B.M. III [Oak Ridge National Lab., TN (United States); Moreshead, W.V.; Nogues, J.L.R. [GELTECH, Inc., Alachua, FL (United States)

    1996-05-01

    Deterministic optics manufacturing, notably single point diamond turning (SPDT) has matured such that the current generation of machines is capable of producing refractive and reflective optics for the visible wavelength region that are quite acceptable for many applications. However, spiral tool marks are still produced that result in unwanted diffractive scattering from grating-like features having a spatial frequency determined by the machine feed, tool radius, and other influences such as vibration and material removal effects. Such regular artifacts are the characteristic of deterministic manufacturing methods such as SPDT. The authors present some initial findings suggesting that fractal, or non-deterministic surfaces can be produced by SPDT through sol-gel replication. The key is the large isotropic shrinkage that occurs through monolithic sol-gel replication (a factor of 2.5) that results in all features, including tooling marks, being reduced by that amount. The large shrinkage itself would be a laudable-enough feature of the replication process. However, by an as-yet-not understood manner, the replication process itself seems to alter the roughness character of the replicated surface such that it appears to be fractal when analyzed using contact profilometry and the power spectrum approach.

  13. Grazing Incidence Neutron Optics

    Science.gov (United States)

    Gubarev, Mikhail V. (Inventor); Ramsey, Brian D. (Inventor); Engelhaupt, Darell E. (Inventor)

    2013-01-01

    Neutron optics based on the two-reflection geometries are capable of controlling beams of long wavelength neutrons with low angular divergence. The preferred mirror fabrication technique is a replication process with electroform nickel replication process being preferable. In the preliminary demonstration test an electroform nickel optics gave the neutron current density gain at the focal spot of the mirror at least 8 for neutron wavelengths in the range from 6 to 20.ANG.. The replication techniques can be also be used to fabricate neutron beam controlling guides.

  14. Pulsed Laser Deposited Nickel Doped Zinc Oxide Thin Films: Structural and Optical Investigations

    Directory of Open Access Journals (Sweden)

    Tanveer A. Dar

    2013-05-01

    Full Text Available Structural and optical studies has been done on Nickel doped Zinc Oxide (NixZn1 – xO, x  0.03, 0.05 and 0.07 by weight thin films prepared by pulsed laser deposition technique. The films are characterized by X-ray diffraction, Uv-vis spectroscopy, X-ray photoelectron spectroscopy. We observed a slight red shift in the optical band gap in the NiZnO subsequent to Ni doping. This shift can be assigned due to the sp-d exchange interaction of Ni- d states with s and p-states of ZnO. Also X-ray photoelectron spectroscopy studies show that Ni has well substituted in + 2 oxidation state by replacing Zn2+.

  15. X-ray analysis and optical properties of nickel oxide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Shaaban, E.R., E-mail: esam_ramadan2008@yahoo.com [Physics Department, Faculty of Science, Al-Azhar University, PO 71452, Assiut (Egypt); Kaid, M.A.; Ali, M.G.S. [Physics Department, Faculty of Science, El-Minia University, El-Minia (Egypt)

    2014-11-15

    Highlights: • A fine NiO powders were prepared by a homogeneous precipitation method. • The microstructure and surface morphology of NiO powder were characterized. • The optical constants and film thicknesses of NiO thin films were obtained by SE. • The change in optical constants and energy gap were interpreted using microstructure parameters. - Abstract: Nanoparticles of NiO were prepared by a homogeneous precipitation method with an aqueous solution of nickel nitrate hexahydrate and citric acid. The microstructure and surface morphology of NiO powder were characterized by thermogravimetric (TGA) analysis, differential scanning calorimeter (DSC), X-ray diffraction (XRD), and infrared (IR) spectroscopy. Different thicknesses of nickel oxide (NiO) thin films were deposited onto highly cleaned glass substrates by the electron beam technique. Their structural characteristics were studied by X-ray diffraction (XRD) and scan electron microscope (SEM). The XRD investigation shows that NiO films are polycrystalline with an cubic type structure. The microstructure parameters, e.g., crystallite size and microstrain were calculated. The optical constants (n, k) and film thicknesses of NiO thin films were obtained by fitting the ellipsometric parameters (ψ and Δ) data using three layer model systems in the wavelength range 300–1100 nm. It is found that the refractive index, n increases with the increase of the film thickness. The possible optical transition in these films is found to be allowed direct transitions. The direct energy gaps increase with increasing of the film thickness.

  16. 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.

  17. Effect of annealing temperature on the optical loss and the optical constants of RF-magnetron sputtered carbon — nickel composite films

    Science.gov (United States)

    Dalouji, V.; Elahi, S. M.

    2014-03-01

    In this work, the optical properties of carbon — nickel films annealed at different temperatures (300-1000 °C) were investigated. The films were grown on quartz substrates by radio frequency magnetron co-sputtering at room temperature with a deposition time of 600 second. The optical transmittance spectra in the wavelength range 300-1000 nm were used to compute the refractive index by using the Swanepoel's method. The films annealed at 500 °C showed considerable optical loss due to optical absorption by nickel atoms and to scattering caused by surface roughness. However, the film annealed at 800 °C had a very small optical loss in spite of the high surface roughness. The dispersion curves of the refractive indices of the films had anomalous dispersion in the absorption region and normal dispersion in the transparent region. The dissipation rate of the electromagnetic wave at 500 °C was shown to have maximum value.

  18. Synthesis of nickel oxide nanoparticles using pulsed laser ablation in liquids and their optical characterization

    Energy Technology Data Exchange (ETDEWEB)

    Gondal, M.A., E-mail: magondal@kfupm.edu.sa [Laser Research Group, Physics Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Center of Excellence in Nanotechnology (CENT), King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Saleh, Tawfik A. [Center of Excellence in Nanotechnology (CENT), King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Chemistry Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Drmosh, Q.A. [Laser Research Group, Physics Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Center of Excellence in Nanotechnology (CENT), King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)

    2012-07-01

    Nanomaterials are of great interest due to their applications in many fields. The structural and efficacy of nano-materials depend strongly on the method applied for their synthesis. In this work, nanosized nickel oxide (NiO) particles were prepared by pulsed laser ablation (PLA) technique in 3% H{sub 2}O{sub 2} aqueous solution The structural and optical properties of the NiO were investigated by X-ray diffractometer (XRD), field emission scanning electron microscope (FE-SEM), energy dispersive X-ray spectroscope (EDX), UV-Vis spectroscopy and Fourier-transform infrared spectroscopy (FT-IR). XRD analysis confirms that the phase is pure nickel oxide with lattice parameter = 0.42033 nm and 8 nm grain size while photoluminescence emission spectrum showed strong peak at 3.62 eV attributed to the band edge transition. FT-IR spectra depicts a strong band at {approx}450 cm{sup -1} which corresponds to the bending vibration of Ni-O bond. This work demonstrates that PLA is an effective method to control the size, impurity and minimal chemical waste generation which is the major problem with other wet chemical methods.

  19. Optical and Electrochemical Properties of Layered Crystals GaSe Intercalated by the Nickel

    Directory of Open Access Journals (Sweden)

    S.G. Barbutsa

    2013-10-01

    Full Text Available The presented results of the investigations of the optical and electrochemical properties indicate the possibility of intercalation of layered GaSe crystals with nickel ions. Established that the electrochemical introduction of Ni leads to a monotonic growth in electrode potential of layered semiconductors GaSe when a concentration of intercalants nNi  1018-1020сm – 3. In consequence of intercalation of nickel in GaSe crystal at T  293 K, occurred ncreases in the energy position of the exciton peak Eeks 6 meV (from 2.008 to 2.014 eV and the half-width of the exciton absorption bands of H by 5.2 meV. At a temperature T  77 K was detected non- monotonous concentration dependence of the excitonic maximum energy location for Еeks NiGaSe compounds. The dependence Еeks(nNi for these compounds are explained as a result of the introduction of competition between contributions of inter - and intralayer deformations which have the opposite signs of deformation potential.

  20. Optical response and magnetic characteristic of samarium doped zinc phosphate glasses containing nickel nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Azmi, Siti Amlah M.; Sahar, M.R., E-mail: mrahim057@gmail.com

    2015-11-01

    A magnetic glass of composition 40ZnO–(58−x) P{sub 2}O{sub 5}–1Sm{sub 2}O{sub 3}–xNiO, with x=0.0, 1.0, 1.5 and 2.0 mol% is prepared by melt-quenching technique. The glass is characterized by X-ray diffraction, high-resolution transmission electron microscope (HRTEM), photoluminescence (PL) spectroscopy and vibrating sample magnetometer (VSM) analysis. The X-rays diffraction confirms the amorphous nature of the glass while the HRTEM analysis reveals the presence of nickel nanoparticles in the glass samples. High-resolution TEM reveals that the lattice spacing of nickel nanoparticles is 0.35 nm at (100) plane. Photoluminescence emission shows the existence of four peaks that correspond to the transition from the upper level of {sup 4}G{sub 5/2} to the lower level of {sup 6}H{sub 5/2}, {sup 6}H{sub 7/2}, {sup 6}H{sub 9/2,} and {sup 6}H{sub 11/2.} It is observed that all peaks experience significant quenching effect with the increasing concentration of nickel nanoparticles, suggesting a strong energy transfer from excited samarium ions to the nickel ions. The glass magnetization and susceptibility at 12 kOe at room temperature are found to be in the range of (3.87±0.17×10{sup −2}–7.19±0.39×10{sup −2}) emu/g and (3.24±0.16×10{sup −6}–5.99±0.29×10{sup −6}) emu/Oe g respectively. The obtained hysteresis curve indicates that the glass samples are paramagnetic materials. The studied glass can be further used towards the development of magneto-optical functional glass. - Highlights: • Sm{sup 3+} doped zinc phosphate glass embedded with Ni NPs has been prepared. • The Laue pattern and lattice spacing of Ni NPs are confirmed by HRTEM image. • The magnetic response of glasses has been studied through VSM analysis. • Enhancement factor and decay half-lifetime are investigated.

  1. An Optically Transparent Iron Nickel Oxide Catalyst for Solar Water Splitting.

    Science.gov (United States)

    Morales-Guio, Carlos G; Mayer, Matthew T; Yella, Aswani; Tilley, S David; Grätzel, Michael; Hu, Xile

    2015-08-12

    Sunlight-driven water splitting to produce hydrogen fuel is an attractive method for renewable energy conversion. Tandem photoelectrochemical water splitting devices utilize two photoabsorbers to harvest the sunlight and drive the water splitting reaction. The absorption of sunlight by electrocatalysts is a severe problem for tandem water splitting devices where light needs to be transmitted through the larger bandgap component to illuminate the smaller bandgap component. Herein, we describe a novel method for the deposition of an optically transparent amorphous iron nickel oxide oxygen evolution electrocatalyst. The catalyst was deposited on both thin film and high-aspect ratio nanostructured hematite photoanodes. The low catalyst loading combined with its high activity at low overpotential results in significant improvement on the onset potential for photoelectrochemical water oxidation. This transparent catalyst further enables the preparation of a stable hematite/perovskite solar cell tandem device, which performs unassisted water splitting.

  2. The influence of nickel dopant on the microstructure and optical properties of SnO2 nano-powders

    Institute of Scientific and Technical Information of China (English)

    Liu Chun-Ming; Fang Li-Mei; Zu Xiao-Tao; Zhou Wei-Lie

    2007-01-01

    The microstructure and optical properties of Ni-doped SnO2 nano-powders are studied in detail. By Ni-doping, not only the grain size reduces, but also the grain shape changes from nano-rods to spherical particles. The crystallization becomes better with annealing temperature increasing. The band gap energy decreases as nickel doping level increases.The sp-d hybridization and alloying effect due to amorphous SnO2-x phase should be responsible for the band gap narrowing effect. Nickel dopant does not change the photoluminescence (PL) peak positions.

  3. High Energy Replicated Optics to Explore the Sun: Hard X-Ray Balloon-Borne Telescope

    Science.gov (United States)

    Gaskin, Jessica; Apple, Jeff; StevensonChavis, Katherine; Dietz, Kurt; Holt, Marlon; Koehler, Heather; Lis, Tomasz; O'Connor, Brian; RodriquezOtero, Miguel; Pryor, Jonathan; Ramsey, Brian; Rinehart-Dawson, Maegan; Smith, Leigh; Sobey, Alexander; Wilson-Hodge, Colleen; Christe, Steven; Cramer, Alexander; Edgerton, Melissa; Rodriquez, Marcello; Shih, Albert; Gregory, Don; Jasper, John; Bohon, Steven

    2013-01-01

    Set to fly in the Fall of 2013 from Ft. Sumner, NM, the High Energy Replicated Optics to Explore the Sun (HEROES) mission is a collaborative effort between the NASA Marshall Space Flight Center and the Goddard Space Flight Center to upgrade an existing payload, the High Energy Replicated Optics (HERO) balloon-borne telescope, to make unique scientific measurements of the Sun and astrophysical targets during the same flight. The HEROES science payload consists of 8 mirror modules, housing a total of 109 grazing-incidence optics. These modules are mounted on a carbon-fiber - and Aluminum optical bench 6 m from a matching array of high pressure xenon gas scintillation proportional counters, which serve as the focal-plane detectors. The HERO gondola utilizes a differential GPS system (backed by a magnetometer) for coarse pointing in the azimuth and a shaft angle encoder plus inclinometer provides the coarse elevation. The HEROES payload will incorporate a new solar aspect system to supplement the existing star camera, for fine pointing during both the day and night. A mechanical shutter will be added to the star camera to protect it during solar observations. HEROES will also implement two novel alignment monitoring system that will measure the alignment between the optical bench and the star camera and between the optics and detectors for improved pointing and post-flight data reconstruction. The overall payload will also be discussed. This mission is funded by the NASA HOPE (Hands On Project Experience) Training Opportunity awarded by the NASA Academy of Program/Project and Engineering Leadership, in partnership with NASA's Science Mission Directorate, Office of the Chief Engineer and Office of the Chief Technologist

  4. High Energy Replicated Optics to Explore the Sun: Hard X-ray balloon-borne telescope

    Science.gov (United States)

    Gaskin, J.; Apple, J.; Chavis, K. S.; Dietz, K.; Holt, M.; Koehler, H.; Lis, T.; O'Connor, B.; Otero, M. R.; Pryor, J.; Ramsey, B.; Rinehart-Dawson, M.; Smith, L.; Sobey, A.; Wilson-Hodge, C.; Christe, S.; Cramer, A.; Edgerton, M.; Rodriguez, M.; Shih, A.; Gregory, D.; Jasper, J.; Bohon, S.

    Set to fly in the Fall of 2013 from Ft. Sumner, NM, the High Energy Replicated Optics to Explore the Sun (HEROES) mission is a collaborative effort between the NASA Marshall Space Flight Center and the Goddard Space Flight Center to upgrade an existing payload, the High Energy Replicated Optics (HERO) balloon-borne telescope, to make unique scientific measurements of the Sun and astrophysical targets during the same flight. The HEROES science payload consists of 8 mirror modules, housing a total of 109 grazing-incidence optics. These modules are mounted on a carbon-fiber - and Aluminum optical bench 6 m from a matching array of high pressure xenon gas scintillation proportional counters, which serve as the focal-plane detectors. The HERO gondola utilizes a differential GPS system (backed by a magnetometer) for coarse pointing in the azimuth and a shaft angle encoder plus inclinometer provides the coarse elevation. The HEROES payload will incorporate a new solar aspect system to supplement the existing star camera, for fine pointing during both the day and night. A mechanical shutter will be added to the star camera to protect it during solar observations. HEROES will also implement two novel alignment monitoring system that will measure the alignment between the optical bench and the star camera and between the optics and detectors for improved pointing and post-flight data reconstruction. The overall payload will also be discussed. This mission is funded by the NASA HOPE (Hands On Project Experience) Training Opportunity awarded by the NASA Academy of Program/Project and Engineering Leadership, in partnership with NASA's Science Mission Directorate, Office of the Chief Engineer and Office of the Chief Technologist.

  5. Studies on the Optical Properties and Surface Morphology of Nickel Phthalocyanine Thin Films

    Directory of Open Access Journals (Sweden)

    Benny Joseph

    2007-01-01

    Full Text Available Thin films of Nickel Phthalocyanine (NiPc are fabricated at a base pressure of 10-5 m.bar using Hind-Hivac thermal evaporation plant. The films are deposited on to glass substrates at various temperatures 318, 363, 408 and 458K. The optical absorption spectra of these thin films are measured. Present studies reveal that the optical band gap energies of NiPc thin films are highly dependent on the substrate temperatures. The structure and surface morphology of the films deposited on glass substrates of temperatures 303, 363 and 458K are studied using X-ray diffractograms and Scanning Electron Micrographs (SEM, show that there is a change in the crystallinity and surface morphology due to change in the substrate temperatures. Full width at half maximum (FWHM intensity of the diffraction peaks is also found reduced with increasing substrate temperatures. Scanning electron micrographs show that these crystals are fiber like at high substrate temperatures. The optical band gap increases with increase in substrate temperature and is then reduced with fiber-like grains at 408K. The band gap increases again at 458K with full of fiber like grains. Trap energy levels are also observed for these films.

  6. Ultrafast Measurement of the Optical Properties of Shocked Nickel and Laser Heated Gold

    Science.gov (United States)

    Funk, David J.; Moore, D. S.; Reho, J. H.; Gahagan, K. T.; McGrane, S. D.; Rabie, R. L.

    2002-07-01

    We have used high-resolution Frequency Domain Interferometry (FDI) to make the first ultrafast measurement of shock-induced changes in the optical properties of thin nickel (approx500 nm) targets. Data taken at several angles of incidence allowed the separation of optical effects from material motion, yielding an effective complex index for the shocked material. In contrast to our previous studies of aluminum, measurements with an 800 nm probe wavelength found a phase shift attributable to optical property changes with the same sign as that due to surface motion, during an 11.5 GPa shock breakout. A similar experiment was attempted with thin gold films (approx180 nm) using Ultrafast Spatial Interferometry (USI). However, since the electron-phonon coupling in gold is extremely weak, a shock is observed as it "forms". Ballistic electrons and electron-electron equilibrium cause fast heating of the electrons in the entire thickness of the thin film, followed by lattice excitation through electron-phonon coupling, eventually leading to melt and frustrated thermal expansion yielding the observed surface motion. We suggest that these experiments offer a new path for observation of phase changes or for temperature measurements, by allowing a determination of the complex index under dynamic loading conditions and comparing the measured values to those obtained under static conditions.

  7. Replicative manufacturing of complex lighting optics by non-isothermal glass molding

    Science.gov (United States)

    Kreilkamp, Holger; Vu, Anh Tuan; Dambon, Olaf; Klocke, Fritz

    2016-09-01

    The advantages of LED lighting, especially its energy efficiency and the long service life have led to a wide distribution of LED technology in the world. However, in order to make fully use of the great potential that LED lighting offers, complex optics are required to distribute the emitted light from the LED efficiently. Nowadays, many applications use polymer optics which can be manufactured at low costs. However, due to ever increasing luminous power, polymer optics reach their technological limits. Due to its outstanding properties, especially its temperature resistance, resistance against UV radiation and its long term stability, glass is the alternative material of choice for the use in LED optics. This research is introducing a new replicative glass manufacturing approach, namely non-isothermal glass molding (NGM) which is able to manufacture complex lighting optics in high volumes at competitive prices. The integration of FEM simulation at the early stage of the process development is presented and helps to guarantee a fast development cycle. A coupled thermo-mechanical model is used to define the geometry of the glass preform as well as to define the mold surface geometry. Furthermore, simulation is used to predict main process outcomes, especially in terms of resulting form accuracy of the molded optics. Experiments conducted on a commercially available molding machine are presented to validate the developed simulation model. Finally, the influence of distinct parameters on important process outcomes like form accuracy, surface roughness, birefringence, etc. is discussed.

  8. Nonlinear and magneto-optical transmission studies on magnetic nanofluids of non-interacting metallic nickel nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Reena Mary, A P; Anantharaman, M R [Department of Physics, Cochin University of Science and Technology, Cochin 682 022 (India); Suchand Sandeep, C S; Philip, Reji [Light and Matter Physics Group, Raman Research Institute, Sadashivanagar, Bangalore-560080 (India); Narayanan, T N; Moloney, Padraig; Ajayan, P M, E-mail: reji@rri.res.in, E-mail: mraiyer@yahoo.com [Department of Mechanical Engineering and Materials Science, Rice University, Houston, TX-77005 (United States)

    2011-09-16

    Oxide free stable metallic nanofluids have the potential for various applications such as in thermal management and inkjet printing apart from being a candidate system for fundamental studies. A stable suspension of nickel nanoparticles of {approx} 5 nm size has been realized by a modified two-step synthesis route. Structural characterization by x-ray diffraction and transmission electron microscopy shows that the nanoparticles are metallic and are phase pure. The nanoparticles exhibited superparamagnetic properties. The magneto-optical transmission properties of the nickel nanofluid (Ni-F) were investigated by linear optical dichroism measurements. The magnetic field dependent light transmission studies exhibited a polarization dependent optical absorption, known as optical dichroism, indicating that the nanoparticles suspended in the fluid are non-interacting and superparamagnetic in nature. The nonlinear optical limiting properties of Ni-F under high input optical fluence were then analyzed by an open aperture z-scan technique. The Ni-F exhibits a saturable absorption at moderate laser intensities while effective two-photon absorption is evident at higher intensities. The Ni-F appears to be a unique material for various optical devices such as field modulated gratings and optical switches which can be controlled by an external magnetic field.

  9. Electrical and optical properties of sub-10 nm nickel silicide films for silicon solar cells

    Science.gov (United States)

    Brahmi, Hatem; Ravipati, Srikanth; Yarali, Milad; Shervin, Shahab; Wang, Weijie; Ryou, Jae-Hyun; Mavrokefalos, Anastassios

    2017-01-01

    Highly conductive and transparent films of ultra-thin p-type nickel silicide films have been prepared by RF magnetron sputtering of nickel on silicon substrates followed by rapid thermal annealing in an inert environment in the temperature range 400-600 °C. The films are uniform throughout the wafer with thicknesses in the range of 3-6 nm. The electrical and optical properties are presented for nickel silicide films with varying thickness. The Drude-Lorentz model and Fresnel equations were used to calculate the dielectric properties, sheet resistance, absorption and transmission of the films. These ultrathin nickel silicide films have excellent optoelectronic properties for p-type contacts with optical transparencies up to 80% and sheet resistance as low as ~0.15 µΩ cm. Furthermore, it was shown that the use of a simple anti-reflection (AR) coating can recover most of the reflected light approaching the values of a standard Si solar cell with the same AR coating. Overall, the combination of ultra-low thickness, high transmittance, low sheet resistance and ability to recover the reflected light by utilizing standard AR coating makes them ideal for utilization in silicon based photovoltaic technologies as a p-type transparent conductor.

  10. Structural, Optical and Electrical Properties of PVA/PANI/Nickel Nanocomposites Synthesized by Gamma Radiolytic Method

    Directory of Open Access Journals (Sweden)

    Abdo Mohd Meftah

    2014-09-01

    Full Text Available This article reports a simultaneous synthesis of polyaniline (PANI and nickel (Ni nanoparticles embedded in polyvinyl alcohol (PVA film matrix by gamma radiolytic method. The mechanism of formation of PANI and Ni nanoparticles were proposed via oxidation of aniline and reduction of Ni ions, respectively. The effects of dose and Ni ions concentration on structural, optical, and electrical properties of the final PVA/PANI/Ni nanocomposites film were carefully examined. The structural and morphological studies show the presence of PANI with irregular granular microstructure and Ni nanoparticles with spherical shape and diameter less than 60 nm. The average particle size of Ni nanoparticles decreased with increasing dose and decreasing of precursor concentration due to increase of nucleation process over aggregation process during gamma irradiation. The optical absorption spectra showed that the absorption peak of Ni nanoparticles at about 390 nm shifted to lower wavelength and the absorbance increased with increasing dose. The formation of PANI was also revealed at 730 nm absorption peak with the absorbance increasing by the increase of dose. The electrical conductivity increased with increasing of dose and chlorine concentration due to number of polarons formation increases in the PVA/PANI/Ni nanocomposites.

  11. Experimental and theoretical studies of the structure and optical properties of nickel phthalocyanine nanowires

    Science.gov (United States)

    Wang, Xiaoyan; Wu, Wei; Ju, Haidong; Zou, Taoyu; Qiao, Zhenfang; Gong, Hao; Wang, Hai

    2016-12-01

    By using organic vapor phase deposition method, nickel phthalocyanines (NiPc) nanowires were successfully prepared, and the effects of heating temperature on the structural and optical properties of NiPc nanowires were investigated. Both the crystal structures of NiPc powders and nanowires are studied by x-ray diffraction patterns (XRD) and Fourier transform infrared spectra (FTIR). The lattice constants of NiPc nanowires from the fitting of XRD patterns are a = 13.04 Å, b = 3.75 Å, c = 24.32 Å, β = 94.10°, belonging to the space group of monoclinic (P21/c). X-ray photo-electron spectroscopy (XPS) suggests main peaks at 284.82 eV and 286.18 eV for C-C and C-N bonds and two peaks at 397.8 eV and 398.8 eV for N-C and the N-Ni bonds, respectively, in NiPc nanowires. FTIR spectra show a structural transition from powder to nanowire. The optical properties of NiPc nanowires have been investigated via a comparison between theoretical and experimental approaches. The most significant absorption peaks of NiPc nanowires in the visible region are located at 626 nm and 672 nm, showing a blue shift comparing with the β-NiPc. We have also theoretically revealed the excitation energies in NiPc single molecule and dimer in the form of α and β phases using time-dependent density-functional theory. These theoretical results are in qualitative agreement with the measurements of optical properties. Moreover, no noticeable change in crystalline form is shown when tuning the heating temperature from 420 °C to 450 °C, suggesting a wide synthesis temperature window. The reduced Ni-Ni distance indicated a clear advantage over powder in terms of potential applications in organic electronics.

  12. Optical and morphological investigation of aluminium and nickel oxide composite films deposited by spray pyrolysis method as a basis of solar thermal absorber

    Indian Academy of Sciences (India)

    A Bagheri Khatibani; S M Rozati

    2015-04-01

    Applications of alumina and nickel oxide in various fields specially in solar energy conversion technology encouraged us to study physical properties of such materials. Hence after the deposition of the thin films on glass substrate by spray pyrolysis, using X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV–visible spectrophotometry, various physical properties were investigated. Different optical quantities such as optical band gap, refractive index, extinction coefficient, dielectric constants, volume and surface energy loss functions and optical conductivity were determined. Within this paper for different nickel to aluminium ratio (from 20/80 to 80/20 ratio) at specific substrate temperatures (300°C), decrease of optical transmittance with nickel content was notable. Using the transmittance data, other optical quantities were achieved by a numerical approximation method. We also observed an increase in the volume energy loss (VELF) more than the surface energy loss (SELF) and simultaneously a decrease trend prevailed according to nickel amount. On the basic of the XRD results, the amorphous phase changed by the presence of more nickel and according to SEM, more obvious nanosized spherical grains at higher nickel ratios can be observed.

  13. Structural, electrical, optical and analytical applications of newly synthesized polyaniline based nickel molybdate composite

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Meraj Alam; Ishrat, Urfi; Dar, Ayaz Mahmood; Ahmad, Anees, E-mail: aneesahmad@yahoo.com

    2015-07-05

    Highlights: • Synthesis of organic–inorganic conducting nano-composite cation-exchanger. • Average particle size was found to be 76 nm. • The nano-composite was found to be selective for Pb(II), Hg(II) and Th(IV) ions. • The nano composite indicated a band gap of about 3.44 eV showing a weak blue shift compared to 3.37 eV. • The binary separations of metal ions are fairly sharp and reproducible with 90–95% recovery. - Abstract: The synthesis of polyaniline based nickel molybdate nano composite cation exchanger was described by sol–gel method and was explored to study the electrical, optical and analytical applications. The nano composite material was characterized by Fourier Transform Infrared (spectrometer), X-ray diffraction, particle size analyzer, scanning electron microscopy and tunneling electron microscopy. The XRD of nano composite material confirmed the semi-crystalline nature while as particle size analysis as well as TEM depicted average particle size of 76 nm. The partition coefficient studies of different metal ions in the composite were performed in demineralised water and sodium dodecyl sulfate surfactant, and it was found to be selective for Pb(II), Hg(II) and Th(IV) ions. To implement the use of polyaniline Ni(II) molybdate nano composite as adsorbent, some important binary separations of metal ions were performed. SEM analysis showed that the nano composite has random non-preferential orientation with no visible cracks and appeared to be composed of dense and loose aggregation of small particles. The UV–vis spectrum of the nano composite indicated a band gap of about 3.44 eV showing a weak blue shift compared to 3.37 eV for the bulk. Due to their optical and electrical properties, nano composite is promising candidate for use as selectivity of different cations.

  14. 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...... was maintained by ingestion of nickel in food....

  15. High Energy Replicated Optics to Explore the Sun Balloon-Borne Telescope: Astrophysical Pointing

    Science.gov (United States)

    Gaskin, Jessica; Wilson-Hodge, Colleen; Ramsey, Brian; Apple, Jeff; Kurt, Dietz; Tennant, Allyn; Swartz, Douglas; Christe, Steven D.; Shih, Albert

    2014-01-01

    On September 21, 2013, the High Energy Replicated Optics to Explore the Sun, or HEROES, balloon-borne x-ray telescope launched from the Columbia Scientific Balloon Facility's site in Ft. Summer, NM. The flight lasted for approximately 27 hours and the observational targets included the Sun and astrophysical sources GRS 1915+105 and the Crab Nebula. Over the past year, the HEROES team upgraded the existing High Energy Replicated Optics (HERO) balloon-borne telescope to make unique scientific measurements of the Sun and astrophysical targets during the same flight. The HEROES Project is a multi-NASA Center effort with team members at both Marshall Space Flight Center (MSFC) and Goddard Space Flight Center (GSFC), and is led by Co-PIs (one at each Center). The HEROES payload consists of the hard X-ray telescope HERO, developed at MSFC, combined with several new systems. To allow the HEROES telescope to make observations of the Sun, a new solar aspect system was added to supplement the existing star camera for fine pointing during both the day and night. A mechanical shutter was added to the star camera to protect it during solar observations and two alignment monitoring systems were added for improved pointing and post-flight data reconstruction. This mission was funded by the NASA HOPE (Hands-On Project Experience) Training Opportunity awarded by the NASA Academy of Program/Project and Engineering Leadership, in partnership with NASA's Science Mission Directorate, Office of the Chief Engineer and Office of the Chief Technologist.

  16. Modification of the physical and optical properties of the frustule of the diatom Coscinodiscus wailesii by nickel sulfate

    Science.gov (United States)

    Townley, Helen E.; Woon, Kai Lin; Payne, Frank P.; White-Cooper, Helen; Parker, Andrew R.

    2007-07-01

    In this paper we demonstrate how the photonic properties of a diatom can be altered by growth with a metal pollutant. Both the optical and physical properties of the silica frustule of the diatom Coscinodiscus wailesii were affected by the presence of nickel sulfate in sea water. It was found that a sublethal concentration of the metal both significantly modified the size of the pores of the valves and quenched the intrinsic PL of the amorphous silica. Since cytoplasmic structures may be involved in determining the frustule architecture, we also present TEMs of nickel-grown diatoms and show the affected organelles. The ability to modify the properties of the frustule shows that mechanisms exist for the alteration of existing structures in nature to optimize specific characteristics for exploitation in biotechnological applications.

  17. Hot-embossing replication of self-centering optical fiber alignment structures prototyped by deep proton writing

    Science.gov (United States)

    Ebraert, Evert; Wissmann, Markus; Guttmann, Markus; Kolew, Alexander; Worgull, Matthias; Barié, Nicole; Schneider, Marc; Hofmann, Andreas; Beri, Stefano; Watté, Jan; Thienpont, Hugo; Van Erps, Jürgen

    2016-07-01

    This paper presents the hot-embossing replication of self-centering fiber alignment structures for high-precision, single-mode optical fiber connectors. To this end, a metal mold insert was fabricated by electroforming a polymer prototype patterned by means of deep proton writing (DPW). To achieve through-hole structures, we developed a postembossing process step to remove the residual layer inherently present in hot-embossed structures. The geometrical characteristics of the hot-embossed replicas are compared, before and after removal of the residual layer, with the DPW prototypes. Initial measurements on the optical performance of the replicas are performed. The successful replication of these components paves the way toward low-cost mass replication of DPW-fabricated prototypes in a variety of high-tech plastics.

  18. Some electrical and optical properties of nickel-related deep levels in silicon. [Si:Ni

    Energy Technology Data Exchange (ETDEWEB)

    Bartos, J. (Inst. of Physics, Slovak Academy of Sciences, Bratislava (Czechoslovakia)); Tesar, L. (Tesla Roznow, Roznov p. Radhostem (Czechoslovakia))

    1990-12-16

    Silicon wafers with p-n junctions are contaminated by nickel and the temperature behaviour of the reverse current of these p-n junctions is investigated. Nickel-related deep energy levels are studied by DLTS measurement. The dominant energy level of Ni is at E{sub v} + 0.31 eV. The illumination and annealing sensitivity of this level is also observed. An attempt is made to explain qualitatively this phenomenon. (orig.).

  19. Anthracene and TCNQ doping of substituted nickel phthalocyanine: Effects on the electrical and optical properties of spin coated thin films

    Directory of Open Access Journals (Sweden)

    Hassan Aseel K.

    2013-08-01

    Full Text Available In this work, we study the controlled doping of thin films of substituted nickel phthalocyanine, NiPcR8, where R=-SC6H13, with anthracene and TCNQ and investigate the effects of the extent of this doping on the optical and electrical properties of NiPcR8 films. Optical constants, namely index of refraction (n and extinction coefficient (k have increased for both types of doping, as determined from spectroscopic ellipsometry measurements. Conductivity is shown to increase by about four orders of magnitudes compared to pure NiPcR8 films as a result of anthracene doping while TCNQ has resulted in almost six orders of magnitudes increase in the film’s conductivity.

  20. Role of oxidative stress and intracellular calcium in nickel carbonate hydroxide-induced sister-chromatid exchange, and alterations in replication index and mitotic index in cultured human peripheral blood lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    M' Bemba-Meka, Prosper [Universite de Montreal, Human Toxicology Research Group (TOXHUM), Department of Environmental and Occupational Health, Main Station, P.O. Box 6128, Montreal, QC (Canada); University of Louisville, Department of Pharmacology and Toxicology, Center for Genetics and Molecular Medicine, Louisville, KY (United States); Lemieux, Nicole [Universite de Montreal, Department of Pathology and Cellular Biology, Faculty of Medicine, Main Station, P.O. Box 6128, Montreal, QC (Canada); Chakrabarti, Saroj K. [Universite de Montreal, Human Toxicology Research Group (TOXHUM), Department of Environmental and Occupational Health, Main Station, P.O. Box 6128, Montreal, QC (Canada)

    2007-02-15

    Human peripheral lymphocytes from whole blood cultures were exposed to either soluble form of nickel carbonate hydroxide (NiCH) (0-60 {mu}M), or of nickel subsulfide (Ni{sub 3}S{sub 2}) (0-120 {mu}M), or of nickel oxide (NiO) (0-120 {mu}M), or nickel sulfate (NiSO{sub 4}) (0-120 {mu}M) for a short duration of 2 h. The treatments occurred 46 h after the beginning of the cultures. The cultures were harvested after a total incubation of 72 h, and sister-chromatid exchange (SCE), replication index (RI), and mitotic index (MI) were measured for each nickel compound. The soluble form of NiCH at 30 {mu}M but those of Ni{sub 3}S{sub 2} and NiO at 120 {mu}M produced significant increase in the SCE per cell compared to the control value, whereas NiSO{sub 4} failed to produce any such significant increase. Except NiSO{sub 4}, the soluble forms of NiCH, Ni{sub 3}S{sub 2}, and NiO produced significant cell-cycle delay (as measured by the inhibition of RI) as well as significant inhibition of the MI at respective similar concentrations as mentioned above. Pretreatment of human blood lymphocytes with catalase (H{sub 2}O{sub 2} scavenger), or superoxide dismutase (superoxide anion scavenger), or dimethylthiourea (hydroxyl radical scavenger), or deferoxamine (iron chelator), or N-acetylcysteine (general antioxidant) inhibited NiCH-induced SCE, and changes in RI and MI. This suggests the participation of oxidative stress involving H{sub 2}O{sub 2}, the superoxide anion radical, the hydroxyl radical, and iron in the NiCH-induced genotoxic responses. Cotreatment of NiCH with either verapamil (inhibitor of intracellular calcium ion ([Ca{sup 2+}]{sub i}) movement through plasma membranes), or dantrolene (inhibitor of [Ca{sup 2+}]{sub i} release from sarcoplasmic reticulum), or BAPTA (Ca{sup 2+} chelator) also inhibited the NiCH-induced responses. These results suggest that [Ca{sup 2+}]{sub i} is also implicated in the genotoxicity of NiCH. Overall these data indicate that various types

  1. Nickel Electroplating

    Institute of Scientific and Technical Information of China (English)

    Toru Murakami; Yasuo Uchikoshiki; Kazutoshi Komori

    2004-01-01

    Nickel electroplating has been used practically for decades, is easy to plate, but there is an unknown interest in it.Nickel electroplating as a basis of surface treatment is shown practically from basics to the applied electronics use. At first the basics of nickel electroplating, for example, purpose, use, merit & demerit, nickel plating solution, current efficiency,limiting current density, additional agents and their behaviors are surveyed. And the points of nickel deposition already practically used such as decorative nickel plating, satin nickel plating and functional nickel plating, which has very high throwing power and has been used for electronics, are described in detail.

  2. Nickel Electroplating

    Institute of Scientific and Technical Information of China (English)

    ToruMurakami; YasuoUchikoshiki; KazutoshiKomori

    2004-01-01

    Nickel electroplating has been used practically for decades, is easy to plate, but there is an unknown interest in it. Nickel electroplating as a basis of surface treatment is shown practically from basics to the applied electronics use. At first the basics of nickel electroplating, for example, purpose, use, merit & demerit, nickel plating solution, current efficiency, limiting current density, additional agents and their behaviors are surveyed. And the points of nickel deposition already practically used such as decorative nickel plating, satin nickel plating and functional nickel plating, which has very high throwing power and has been used for electronics, are described in detail.

  3. Role of nickel doping on structural, optical, magnetic properties and antibacterial activity of ZnO nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Vijayaprasath, G.; Murugan, R. [School of Physics, Alagappa University, Karaikudi 630 004, Tamil Nadu (India); Palanisamy, S.; Prabhu, N.M. [Department of Animal Health and Management, Alagappa University, Karaikudi 630 004, Tamil Nadu (India); Mahalingam, T. [Department of Electrical and Computer Engineering, Ajou University, Suwon 443-749 (Korea, Republic of); Hayakawa, Y. [Research Institute of Electronics, Shizuoka University, Hamamatsu 432-8011 (Japan); Ravi, G., E-mail: gravicrc@gmail.com [School of Physics, Alagappa University, Karaikudi 630 004, Tamil Nadu (India)

    2016-04-15

    Highlights: • The XRD analyses revealed that the synthesizes nickel doped ZnO (Zn{sub 1−x}Ni{sub x}O, x = 0.0, 0.03, 0.06 and 0.09) nanostructures have hexagonal wurtzite structure. • The photoluminescence measurements revealed that the broad emission was composed of different bands due to zinc and oxygen vacancies. • X-ray photoelectron spectroscopy (XPS) confirmed the Ni incorporation in ZnO lattice as Ni{sup 2+} ions. • Room temperature ferromagnetism was observed due to the oxygen vacancies and zinc interstitials are the main reasons for ferromagnetism in Ni doped ZnO NPs. - Abstract: Zn{sub 1−x}Ni{sub x}O nanoparticles were synthesized by co-precipitation method. The crystallite sizes of the synthesized samples found to decrease from 38 to 26 nm with increase in nickel concentration. FTIR spectra confirmed the presence of Zn−O stretching bands at 577, 573, 569 and 565 cm{sup −1} in the respective ZnO NPs. Optical absorption spectra revealed the red shifted and estimated band gap is found to decrease with increase of Ni doping concentration. The PL spectra of all the samples exhibited a broad emission at 390 nm in the visible range. The carriers (donors) bounded on the Ni sites were observed from the micro Raman spectroscopic studies. Pure and Ni doped ZnO NPs showed significant changes in the M–H loop, especially the diamagnetic behavior changed into ferromagnetic nature for Ni doped samples. The antiferromagnetic super-exchange interactions between Ni{sup 2+} ions is increased in higher Ni doped ZnO NPs and also their antibacterial activity has been studied.

  4. Formation of Optical Waveguide and Annealing Behaviour of LiNbO3 Implanted by 3.0- MeV Nickel Ions

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ting-Ting; LU Fei; LI Shi-Ling; WANG Xue-Lin; SHEN Ding-Yu; MA Hong-Ji

    2004-01-01

    @@ The optically polished LiNbO3 crystal was implanted with 3.0 MeV nickel ions to a dose of 8 × 10T14 ions/cm2. The implanted sample was orderly annealed at different temperatures for different times in air ambient. The waveguide properties before and after annealing were investigated. Dark modes were observed by the prism coupling technique. The reconstructed refractive index profiles were obtained with the reflectivity calculation method.

  5. Optical Dispersion, Permittivity Spectrum and Thermal-Lensing Effect in Nickel-Doped Zinc Sulfide Nanoparticles

    Science.gov (United States)

    Abbasi, F.; Koushki, E.; Majles Ara, M. H.; Sahraei, R.

    2017-07-01

    In this paper, Ni-doped ZnS (ZnS:Ni2+) nanoparticles (NPs) have been prepared through a chemical method. The average size of the particle is 45 nm. Thin films of the particles have been prepared by using the spin-coating method. The linear and nonlinear optical properties of Ni-doped ZnS thin films and the colloidal solution of them have been studied widely. Using a precise numerical method, the refractive index curve (dispersion curve), absorption coefficient and optical permittivity of Ni-doped ZnS film have been obtained. Using these values, the absorption coefficient of the colloidal solution of Ni-doped ZnS particles has been simulated and compared with experimental results. Finally, using the z-scan method at low laser irradiation, the thermo-optical effect has been studied and the nonlinear refractive index due to this effect has been reported.

  6. AS04-AS02-133 Electroformed-Nickel Hard-X-Ray Optic Development at NASA/MSFC

    Science.gov (United States)

    Ramsey, Brian; Eisner, Ron; Engelhaupt, Darell; Gubarev, Mikhail; Kolodziejczak, Jeffrey; ODell, Stephen; Speegle, Chet; Weisskopf, Martin

    2004-01-01

    We are developing the nickel electroforming process to fabricate high-quality mirrors for the region. Two applications for these optics are a balloon-borne payload, termed HERO, and a hard-X-ray telescope module for consideration for the Constellation-X mission. In the formation on shells, of 15 arcsec angular resolution, will provide over 200 sq cm of effective collecting area unprecedented sensitivity in the 20-75 keV region. A first flight of a partial payload, feature approximately 1/4 of the total collecting area, is scheduled for the Spring of 2004. In the Co-application, two mirror shells, of diameters 150 and 230 mm, are being fabricated. This is particularly challenging as high angular resolution must be maintained with shells of only 1 mm thickness (driven by the tight weight budget for the mission). Further, the shells must be low (less than 5 A on sub-micron spatial scales) to permit efficient use of planned multilayer coatings which must release cleanly from their forming mandrels without any surface degradation.

  7. 镍系胶光氧老化过程研究%Nickel-oxygen aging process of plastic optical

    Institute of Scientific and Technical Information of China (English)

    马燕; 王吉德; 李保华; 王强

    2012-01-01

    This work introduces the liquid nuclear magnetic resonance spectroscopy ( NMR) , Fourier transform infrared spectroscopy (FT-IR) .scanning electron microscopy (SEM) and thermal gravimetric analysis ( TGA ) analysis of four modern light oxygen in rubber aging analysis application. NMR method to analyze the chain unit segment of rubber composition , FT-IR method can glue in the optical characterization of nickel oxide in the aging process dynamic variation of molecular structure,SEM to research samples of the aggregation state and low temperature crystallization behavior,TGA to indicated the thermal stability of samples.%介绍了液体核磁共振波谱法(NMR)、傅里叶变换红外光谱法(FT-IR)、扫描电镜(SEM)和热失重分析(TGA)4种现代分析方法在橡胶光氧老化分析中的应用.NMR法能分析橡胶链中单元链节的组成、FTIR法能表征镍系胶在光氧老化过程中分子结构的动态变化结果,SEM能研究样品的聚集状态及低温下的结晶行为,TG研究样品的热稳定性等.

  8. Structural, optical and electrical properties of chemically derived nickel substituted zinc ferrite nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Chakrabarty, S. [Department of Physics, The University of Burdwan, Burdwan 713 104 (India); Pal, M., E-mail: palm@cgcri.res.in [CSIR-Central Glass and Ceramic Research Institute, Kolkata 700032 (India); Dutta, A., E-mail: adutta@phys.buruniv.ac.in [Department of Physics, The University of Burdwan, Burdwan 713 104 (India)

    2015-03-01

    Single phase spinel Ni substituted nanocrystalline Zn ferrites have been synthesized using a soft chemical route. Effect of Ni substitution on structure, electrical and optical properties has been investigated. X-ray diffraction study confirms the growth of single phase nanocrystalline Ni substituted Zn ferrites. FTIR and UV–Visible studies delineate the change in structure and optical band gap due to inclusion of Ni ions. Substitution of Ni ion has been manifested on lattice parameter which systematically decreases from 8.448 Å to 8.280 Å. An initial increase followed by subsequent decrease in optical band gap with the increase in Ni content is observed. In addition, both ac and dc electrical studies shows anomalous behavior in conductivity and dielectric properties for the samples having Ni content in the range 0.2–0.6 mol fraction which can be attributed to the normal to inverse spinel structural changes. - Highlights: • Pure single phase nanocrystalline Zn/Ni ferrites by facile soft chemical route. • Changes in microstructural parameters of Zn ferrite is observed due to Ni inclusion. • Optical band gap shows a maximum while the concentration of Ni increases. • Inverse to spinal ferrite change is observed in ac and dc electrical properties.

  9. Simultaneous Replication of both Refractive and Diffractive Optical Components using Electroformed Tools and Injection Moulding

    DEFF Research Database (Denmark)

    Tang, Peter Torben; Christensen, Thomas R.

    2003-01-01

    the delicate optical surfaces are buried/sealed in the metal sandwich. The aluminium is then dissolved in warm sodium hydroxide and the glass components are carefully removed. Finally, glue residue is dissolved and the thin gold layer selectively etched. The finished tool insert is then placed in the injection...

  10. Replication quality control of metal and polymer micro structured optical surfaces

    DEFF Research Database (Denmark)

    Gasparin, Stefania; Tosello, Guido; Hansen, Hans Nørgaard;

    2011-01-01

    Non contact measurements are preferred for the characterization of ultra-finely finished surfaces which is particularly challenging if damages of the structures should be avoided. However, it is not always possible to use these methods because low roughness in metallic materials, as optical surfa...

  11. Simultaneous Replication of both Refractive and Diffractive Optical Components using Electroformed Tools and Injection Moulding

    DEFF Research Database (Denmark)

    Tang, Peter Torben; Christensen, Thomas R.

    2003-01-01

    the delicate optical surfaces are buried/sealed in the metal sandwich. The aluminium is then dissolved in warm sodium hydroxide and the glass components are carefully removed. Finally, glue residue is dissolved and the thin gold layer selectively etched. The finished tool insert is then placed in the injection...

  12. Effect of copper and nickel doping on the optical and structural properties of ZnO

    Science.gov (United States)

    Muǧlu, G. Merhan; Sarıtaş, S.; ćakıcı, T.; Şakar, B.; Yıldırım, M.

    2017-02-01

    The present study is focused on the Cu doped ZnO and Ni doped ZnO dilute magnetic semiconductor thin films. ZnO:Cu and ZnO:Ni thin films were grown by Chemically Spray Pyrolysis (CSP) method on glass substrates. Optical analysis of the films was done spectral absorption and transmittance measurements by UV-Vis double beam spectrophotometer technique. The structure, morphology, topology and elemental analysis of ZnO:Cu and ZnO:Ni dilute magnetic thin films were investigated by X-ray diffraction (XRD), Raman Analysis, field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM) techniques, respectively. Also The magnetic properties of the ZnO:Ni thin film was investigated by vibrating sample magnetometer (VSM) method. VSM measurements of ZnO:Ni thin film showed that the ferromagnetic behavior.

  13. Dip coated nickel zinc oxide thin films: Structural, optical and magnetic investigations

    Science.gov (United States)

    Kayani, Zohra Nazir; Kiran, Faiza; Riaz, Saira; Zia, Rehana; Naseem, Shahzad

    2015-01-01

    Dip-coating technique was used to deposit NiZnO thin films on glass substrates at varying withdrawal speed in the range of 150-350 mm/s and annealed at 500 °C for 4 h. X-ray diffraction (XRD) results showed that the deposited NiZnO thin films have a pure wurtzite structure without any significant change in the structure caused by substituting Zn ion with Ni ion. Crystallite size increased from 248 to 497 nm with increase in withdrawal speed. Vibrating Sample magnetometer (VSM) results indicated that NiZnO thin films exhibit ferromagnetic properties. Increase in saturation magnetization with increase in withdrawal speed is observed. Evaluated optical band gap of the films reduced from 3.18 eV to 2.50 eV with the increase in withdrawal speed of the substrate.

  14. Robo-AO: autonomous and replicable laser-adaptive-optics and science system

    CERN Document Server

    Baranec, C; Ramaprakash, A N; Law, N; Tendulkar, S; Kulkarni, S; Dekany, R; Bui, K; Davis, J; Burse, M; Das, H; Hildebrandt, S; Punnadi, S; Smith, R; 10.1117/12.924867

    2012-01-01

    We have created a new autonomous laser-guide-star adaptive-optics (AO) instrument on the 60-inch (1.5-m) telescope at Palomar Observatory called Robo-AO. The instrument enables diffraction-limited resolution observing in the visible and near-infrared with the ability to observe well over one-hundred targets per night due to its fully robotic operation. Robo- AO is being used for AO surveys of targets numbering in the thousands, rapid AO imaging of transient events and longterm AO monitoring not feasible on large diameter telescope systems. We have taken advantage of cost-effective advances in deformable mirror and laser technology while engineering Robo-AO with the intention of cloning the system for other few-meter class telescopes around the world.

  15. Robo-AO: autonomous and replicable laser-adaptive-optics and science system

    Science.gov (United States)

    Baranec, C.; Riddle, R.; Ramaprakash, A. N.; Law, N.; Tendulkar, S.; Kulkarni, S.; Dekany, R.; Bui, K.; Davis, J.; Burse, M.; Das, H.; Hildebrandt, S.; Punnadi, S.; Smith, R.

    2012-07-01

    We have created a new autonomous laser-guide-star adaptive-optics (AO) instrument on the 60-inch (1.5-m) telescope at Palomar Observatory called Robo-AO. The instrument enables diffraction-limited resolution observing in the visible and near-infrared with the ability to observe well over one-hundred targets per night due to its fully robotic operation. Robo-AO is being used for AO surveys of targets numbering in the thousands, rapid AO imaging of transient events and long-term AO monitoring not feasible on large diameter telescope systems. We have taken advantage of cost-effective advances in deformable mirror and laser technology while engineering Robo-AO with the intention of cloning the system for other few-meter class telescopes around the world.

  16. Influence of bis-thiourea nickel nitrate on the structural, optical, electrical, thermal and mechanical behavior of a KDP single crystal for NLO applications

    Science.gov (United States)

    Rasal, Y. B.; Shaikh, R. N.; Shirsat, M. D.; Kalainathan, S.; Hussaini, S. S.

    2017-03-01

    A single crystal of bis-thiourea nickel nitrate (BTNN) doped potassium dihydrogen phosphate (KDP) has been grown from solution at room temperature by a slow evaporation technique. The cell parameters of the grown crystals were determined using single crystal x-ray diffraction analysis. The different functional groups of the grown crystal were confirmed using Fourier transform infrared analysis. The improved optical parameters of the grown crystal have been evaluated in the range of 200-900 nm using UV-visible spectral analysis. The grown crystal was transparent in the entire visible region and the band gap value was found to be 4.96 eV. The influence of BTNN on the third order nonlinear optical properties of KDP crystal has been investigated by means of the Z-scan technique. The second harmonic generation (SHG) efficiency of grown crystal measured using a Nd-YAG laser is 1.98 times higher than that of pure KDP. The third order nonlinear optical susceptibility (χ 3) and nonlinear absorption coefficient (β) of BTNN doped KDP crystal is found to be 1.77  ×  10-5 esu and 5.57  ×  10-6 cm W-1 respectively. The laser damage threshold (LDT) energy for the grown crystal has been measured by using a Q-switched Nd:YAG laser source. The bis-thiourea nickel nitrate shows authoritative impact on the dielectric properties of doped crystal. The influence of bis-thiourea nickel nitrate on the mechanical behavior of KDP crystal has been investigated using Vickers microhardness intender. The thermal behavior of BTNN doped KDP crystal has been analyzed by TGA/DTA analysis.

  17. Nickel Farm

    Institute of Scientific and Technical Information of China (English)

    1995-01-01

    Most plants find nickel to be pretty nasty stuff, and they won’t grow in soils rich in the metal.Streptanthus polygaloides. on the other hand.loves nickel.This member of the mustard family grows only in high-nickel soil in the shadow of the Sierra Nevada,in central California.Streptanthus is a rare type of plant known as a "hyperaccumulator." All plants take up nutrients

  18. The effects of nickel-pigmented aluminium oxide selective coating over aluminium alloy on the optical properties and thermal efficiency of the selective absorber prepared by alternate and reverse periodic plating technique

    Energy Technology Data Exchange (ETDEWEB)

    Wazwaz, A. [Chemical Engineering Department, College of Engineering, Dhofar University, P.O. Box 2509, Postal Code 211, Salalah (Oman); Salmi, J. [Marion Technologies Nanomaterials, Nanostructured Materials and Ceramic Powders, Cap Delta - Parc Technologique, Delta Sud, F-09340 Verniolle (France); Bes, R. [CIRIMAT/LCMIE, Universite Paul Sabatier, 31062 Toulouse Cedex 4 (France)

    2010-08-15

    Diffused reflectance measurements and Kubelka-Munk values were studied. The effects of the alumina layer and the nickel content on the optical properties of the selective absorber were discussed. In general and with respect to aluminium alloy substrate, the diffused reflectance decreased by 85.25-91.42% ({+-}0.01%). The emissivity increased by a factor of 252.50-624.50 ({+-}0.01). The average absorptivity increased by a factor of 4.99-5.35 ({+-}0.01). The average thermal efficiency is increased by a factor of 4.51-4.80 ({+-}0.01). The sample of nickel content 60 {mu}g/cm{sup 2} was found to have the optimum optical properties as a good selective absorber. It has the highest solar selectivity by the two measurements. The range of hemispherical solar selectivity is 4.22-8.36 ({+-}0.01); while for average solar selectivity is 7.410-17.456 ({+-}0.001). We found that the thermal efficiency is increased by increasing the nickel content to a certain limit (60 {mu}g/cm{sup 2}) then it decreased after this limit due to the increase in the emissivity. Also, the total hemispherical optical properties are accordance with the averaged optical properties obtained from diffused reflectance measurements over the solar range. The nickel-pigmented aluminium oxide is one of the best selective absorbers for the photo thermal conversion and it is of high durability. (author)

  19. Comparison of roll-to-roll replication approaches for microfluidic and optical functions in lab-on-a-chip diagnostic devices

    Science.gov (United States)

    Brecher, Christian; Baum, Christoph; Bastuck, Thomas

    2015-03-01

    Economically advantageous microfabrication technologies for lab-on-a-chip diagnostic devices substituting commonly used glass etching or injection molding processes are one of the key enablers for the emerging market of microfluidic devices. On-site detection in fields of life sciences, point of care diagnostics and environmental analysis requires compact, disposable and highly functionalized systems. Roll-to-roll production as a high volume process has become the emerging fabrication technology for integrated, complex high technology products within recent years (e.g. fuel cells). Differently functionalized polymer films enable researchers to create a new generation of lab-on-a-chip devices by combining electronic, microfluidic and optical functions in multilayer architecture. For replication of microfluidic and optical functions via roll-to-roll production process competitive approaches are available. One of them is to imprint fluidic channels and optical structures of micro- or nanometer scale from embossing rollers into ultraviolet (UV) curable lacquers on polymer substrates. Depending on dimension, shape and quantity of those structures there are alternative manufacturing technologies for the embossing roller. Ultra-precise diamond turning, electroforming or casting polymer materials are used either for direct structuring or manufacturing of roller sleeves. Mastering methods are selected for application considering replication quality required and structure complexity. Criteria for the replication quality are surface roughness and contour accuracy. Structure complexity is evaluated by shapes producible (e.g. linear, circular) and aspect ratio. Costs for the mastering process and structure lifetime are major cost factors. The alternative replication approaches are introduced and analyzed corresponding to the criteria presented. Advantages and drawbacks of each technology are discussed and exemplary applications are presented.

  20. Electrostatic self-assembled design strategy for tetracarboxylic Nickel(II) naphthalocyanine ultrathin film for high-performance nonlinear optical properties

    Science.gov (United States)

    Song, Weina; Xiao, Xiangwu; He, Chunying; Mao, Guijie; Gao, Yachen; Chen, Zhimin; Dong, Yongli; Wu, Yiqun

    2016-10-01

    The rational design and controllable preparation of the solid film with strong molecular coupled effect represents a long-standing challenge for developing advanced practical nonlinear optical (NLO) materials. Here, we report a general electrostatic self-assembled strategy toward fabricating tetracarboxylic Nickel(II) naphthalocyanine (NiNcC4) ultrathin film on solid substrate with an ordered molecular arrangement based on the controllable deposition of anionic NiNcC4 naphthalocyanine and cationic polydiallydimethyldiallylammonium chloride (PDDA). The 30-bilayer P/NiNcC4 film shows an ordered conformation of face-to-face molecular arrangement, ultrathin thickness (126.6 nm) and a Raman enhancement phenomenon, and exhibits a high second-order molecular hyperpolarizability γ of 7.0 × 10-27 esu, which is three orders larger than that of NiNcC4 aqueous solution, demonstrating the potential of strongly molecular coupling effects for advanced self-assembled systems.

  1. Nickel allergy

    DEFF Research Database (Denmark)

    Fischer, L A; Johansen, J D; Menné, T

    2007-01-01

    BACKGROUND: The frequency of nickel allergy varies between different population groups. Exposure regulation has proven effective in decreasing the frequency. Experimental studies with other allergens have shown a significant relation between patch test reactivity and repeated open application test.......78 microg nickel cm(-2) in the patch test. The threshold for the ROAT (in microg nickel cm(-2) per application) was significantly lower than the threshold for the patch test, while the dose-response for the accumulated ROAT dose at 1 week, 2 weeks and 3 weeks was very similar to the patch test dose......-response; indeed, there was no statistically significant difference. CONCLUSIONS: For elicitation of nickel allergy the elicitation threshold for the patch test is higher than the elicitation threshold (per application) for the ROAT, but is approximately the same as the accumulated elicitation threshold...

  2. Synthesis, Crystal Structure and Nonlinear Optical Properties of Nickel(Ⅱ) Complex with Schiff-base Ligand

    Institute of Scientific and Technical Information of China (English)

    XUE Zhao-Ming(薛照明); ZHANG Xuan-Jun(张宣军); TIAN Yu-Peng(田玉鹏); WU Jie-Ying(吴杰颖); JIANG Min-Hua(蒋民华); FUN Hoong Kun

    2003-01-01

    The nickel(Ⅱ) complex with the new ligand of S-benzyl-β-N-[10-ethylphenothiazine-3-methylene]dithiocarbazate(HL) crystallizes in the triclinic system, space group P1-with a = 7.516(1), b = 11.322(1), c = 13.366(1) (A),α= 84.818(1),β= 81.688(1), y= 76.037(1)°, V= 1090.26(3) (A)3, Z = 1, Dc=1.413 g/cm3, F(000) = 482,μ(MoKα)= 0.774 mm-1 (λ= 0.7103(A)),R = 0.0573 and wR =0.1375 for 3357 observed reflections withⅠ≥ 2σ(Ⅰ). The HL has lost a proton from its tautomeric thiol form and acts as a single negatively charged bidentate ligand coordinating to the nickel ion via the mercapto sulfur and β-nitrogen atoms. The geometry around Ni(Ⅱ) is almost square-planar with two equivalent Ni-N and Ni-S bonds. The nonlinear absorption of HL and NiL2 solutions (in DMF) was measured by open-aperture Z-scan technique at the wavelength of 532 nm.

  3. Optical and electrical properties of lithium doped nickel oxide films deposited by spray pyrolysis onto alumina substrates

    Science.gov (United States)

    Garduño, I. A.; Alonso, J. C.; Bizarro, M.; Ortega, R.; Rodríguez-Fernández, L.; Ortiz, A.

    2010-11-01

    Non-doped and lithium doped nickel oxide crystalline films have been prepared onto quartz and crystalline alumina substrates at high substrate temperature (600 °C) by the pneumatic spray pyrolysis process using nickel and lithium acetates as source materials. The structure of all the deposited films was the crystalline cubic phase related to NiO, although this crystalline structure was a little bit stressed for the films with higher lithium concentration. The grain size had values between 60 and 70 nm, almost independently of doping concentration. The non-doped and lithium doped films have an energy band gap of the order of 3.6 eV. Hot point probe results show that all deposited films have a p-type semiconductor behavior. From current-voltage measurements it was observed that the electrical resistivity decreases as the lithium concentration increases, indicating that the doping action of lithium is carried out. The electrical resistivity changed from 10 6 Ω cm for the non-doped films up to 10 2 Ω cm for the films prepared with the highest doping concentration.

  4. Nickel metallomics: general themes guiding nickel homeostasis.

    Science.gov (United States)

    Sydor, Andrew M; Zamble, Deborah B

    2013-01-01

    The nickel metallome describes the distribution and speciation of nickel within the cells of organisms that utilize this element. This distribution is a consequence of nickel homeostasis, which includes import, storage, and export of nickel, incorporation into metalloenzymes, and the modulation of these and associated cellular systems through nickel-regulated transcription. In this chapter, we review the current knowledge of the most common nickel proteins in prokaryotic organisms with a focus on their coordination environments. Several underlying themes emerge upon review of these nickel systems, which illustrate the common principles applied by nature to shape the nickel metallome of the cell.

  5. The correlation between magneto-optical response and magnetic dipole resonance excitation in subwavelength silicon-nickel nanogratings

    Science.gov (United States)

    Musorin, A. I.; Barsukova, M. G.; Shorokhov, A. S.; Neshev, D. N.; Kivshar, Y. S.; Fedyanin, A. A.

    2017-09-01

    The advantages of gyrotopic materials are combined with the field of high-index metamaterials. The enhancement of the magneto-optical response in the spectral vicinity of the magnetic dipole resonance of a dielectric silicon nanodisks is numerically shown.

  6. Fabrication and characterization of replicated and lacquer-coated grazing incidence optics for x-ray astronomy

    Energy Technology Data Exchange (ETDEWEB)

    Ulmer, M.P. (Northwestern Univ., Dept. of Physics and Astronomy, Evanston, IL (US)); Haidle, R.; Altkorn, R. (Northwestern Univ., Basic Industry Research Lab., Evanston, IL (US)); Georgopoulos, P. (Northwestern Univ., Dept. of Material Science, Evanston, IL (US)); Rodricks, B. (Argonne National Lab., Advanced Photon Source, Argonne, IL (US)); Takacs, P.Z. (Brookhaven National Lab., Instrumentation Div., Upton, NY (US))

    1991-08-01

    In this paper, the authors discuss the fabrication and testing of electroformed replica Wolter I optics made from gold-coated lacquered mandrels. The authors also discuss testing of gold- and palladium-coated lacquered test flats. X-ray (5 keV for Wolter I mirror and 8 to 40 keV for test flats) and optical (Wyko NCP-1000 profiler) measurements were used to evaluate the mirrors.

  7. Fabrication and characterization of replicated and lacquer-coated grazing incidence optics for X-ray astronomy

    Science.gov (United States)

    Ulmer, Melville P.; Haidle, R.; Altkorn, R.; Georgopoulos, P.; Rodricks, B.; Takacs, P. Z.

    1991-01-01

    The fabrication and testing of electroformed replica Wolter I optics made from gold-coated lacquered mandrels are discussed. Also discussed is the testing of gold- and palladium-coated lacquered test flats. X-ray (5 keV for Wolter I mirror and 8-40 keV for test flats) and optical (NCP-1000 profiler) measurements were used to evaluate the mirrors.

  8. Oxide Nanostructures: Characterizations and Optical Bandgap Evaluations of Cobalt-Manganese and Nickel-Manganese at Different Temperatures

    Directory of Open Access Journals (Sweden)

    C.R. Indulal

    2011-01-01

    Full Text Available Cobalt-Manganese and Nickel-Manganese oxide (CoMnO and NiMnO nanoparticles were prepared by chemical co-precipitation method by decomposition of their respective metal sulfides and sodium carbonate using ethylene diamene tetra acetic acid as the capping agent. The samples were heated at 400, 600 and 800 °C. The average particle sizes were determined from the X-ray line broadening. The diffractograms were compared with JCPDS data to identify the crystallographic phase and cubic structure of the particles. The samples were characterized by XRD, FTIR and UV analyses. The internal elastic micro strains were calculated and it was seen that as the particle size increases strain decreases. The FTIR studies have been used to confirm the metal oxide formation. The chemical compositions of the samples were verified using EDX spectra. The surface morphologies of the samples were studied from the SEM images. The absorption spectra of the materials in the UV-Vis-NIR range were recorded. From the analysis of the absorption spectra, the direct band gaps of the materials were calculated.

  9. Poly (dimethyl siloxane) micro/nanostructure replication using proton beam written masters

    Science.gov (United States)

    Shao, P. G.; van Kan, J. A.; Ansari, K.; Bettiol, A. A.; Watt, F.

    2007-07-01

    Proton beam writing (PBW) has been proven to be a powerful tool for fabricating micro and nanostructures with high aspect ratio. However, being a direct-write technique, and therefore, a serial process, PBW is not economic for low cost multiple component production. Techniques for replicating PBW structures with low cost are necessary for applications in for example nanofluidics, tissue engineering and optical devices. We have investigated casting poly (dimethyl siloxane) (PDMS Sylgard 184, Dow Corning Corp.) with PBW structures as masters. First, a 2 MeV focused H2+ beam was written into a 2 μm thick PMMA layer spin coated onto 50 μm thick Kapton film substrate. Next, these PMMA structures, with details down to 700 nm, were replicated with PDMS. Without any release coating treatment, PDMS circular pillars, 700 nm in diameter were successfully replicated. We also fabricated a nickel master with nanofeature dimensions and 2 μm depth using proton beam writing and sulfamate electroplating. The nickel master was used to successfully replicate a prototype DNA separation chip using PDMS.

  10. Determination of arsenic, cadmium, cobalt, chromium, lead, molybdenum, nickel, and selenium in fertilizers by microwave digestion and inductively coupled plasma-optical emission spectrometry detection: collaborative study.

    Science.gov (United States)

    Kane, Peter F; Hall, William L

    2006-01-01

    There is increasing regulatory interest in the non-nutritive metals content of fertilizer materials, but at present there is no consensus analytical method for acid digestion and instrument detection of those elements in fertilizer matrixes. This lack of method standardization has resulted in unacceptable variability of results between fertilizer laboratories performing metals analysis. A method has been developed using microwave digestion with nitric acid at 200 degrees C, followed by inductively coupled plasma-optical emission spectrometry instrument detection, for the elements arsenic, cadmium, cobalt, chromium, molybdenum, nickel, lead, and selenium. The method has been collaboratively studied, and statistical results are here reported. Fourteen collaborators were sent 62 sample materials in a blind duplicate design. Materials represented a broad cross section of fertilizer types, including phosphate ore, manufactured phosphate products, N-P-K blends, organic fertilizers, and micro-nutrient materials. As much as possible within the limit of the number of samples, materials were selected from different regions of the United States and the world. Limit of detection (LOD) was determined using synthetic fertilizers consisting of reagent grade chemicals with near zero levels of the non-nutritive elements, analyzed blindly. Samples with high iron content caused the most variability between laboratories. Most samples reasonably above LOD gave HorRat values within the range 0.5 to 2.0, indicating acceptable method performance according to AOAC guidelines for analyses in the mg/kg range. The method is recommended for AOAC Official First Action status.

  11. Photoplastic near-field optical probe with sub-100 nm aperture made by replication from a nanomould

    NARCIS (Netherlands)

    Kim, G.M.; Kim, B.J.; Have, ten E.S.; Segerink, F.; Hulst, van N.F.; Brugger, J.

    2003-01-01

    Polymers have the ability to conform to surface contours down to a few nanometres. We studied the filling of transparent epoxy-type EPON SU-8 into nanoscale apertures made in a thin metal film as a new method for polymer/metal near-field optical structures. Mould replica processes combining silicon

  12. Database Replication

    CERN Document Server

    Kemme, Bettina

    2010-01-01

    Database replication is widely used for fault-tolerance, scalability and performance. The failure of one database replica does not stop the system from working as available replicas can take over the tasks of the failed replica. Scalability can be achieved by distributing the load across all replicas, and adding new replicas should the load increase. Finally, database replication can provide fast local access, even if clients are geographically distributed clients, if data copies are located close to clients. Despite its advantages, replication is not a straightforward technique to apply, and

  13. The Development of Replicated Optical Integral Field Spectrographs and their Application to the Study of Lyman-alpha Emission at Moderate Redshifts

    Science.gov (United States)

    Chonis, Taylor Steven

    In the upcoming era of extremely large ground-based astronomical telescopes, the design of wide-field spectroscopic survey instrumentation has become increasingly complex due to the linear growth of instrument pupil size with telescope diameter for a constant spectral resolving power. The upcoming Visible Integral field Replicable Unit Spectrograph (VIRUS), a baseline array of 150 copies of a simple integral field spectrograph that will be fed by 3:36 x 104 optical fibers on the upgraded Hobby-Eberly Telescope (HET) at McDonald Observatory, represents one of the first uses of large-scale replication to break the relationship between instrument pupil size and telescope diameter. By dividing the telescope's field of view between a large number of smaller and more manageable instruments, the total information grasp of a traditional monolithic survey spectrograph can be achieved at a fraction of the cost and engineering complexity. To highlight the power of this method, VIRUS will execute the HET Dark Energy Experiment (HETDEX) and survey & 420 degrees2 of sky to an emission line flux limit of ˜ 10-17 erg s-1 cm -2 to detect ˜ 106 Lyman-alpha emitting galaxies (LAEs) as probes of large-scale structure at redshifts of 1:9 ProQuest.).

  14. Replication of micro and nano surface geometries

    DEFF Research Database (Denmark)

    Hansen, Hans Nørgaard; Hocken, R.J.; Tosello, Guido

    2011-01-01

    : manufacture of net-shape micro/nano surfaces, tooling (i.e. master making), and surface quality control (metrology, inspection). Replication processes and methods as well as the metrology of surfaces to determine the degree of replication are presented and classified. Examples from various application areas...... are given including replication for surface texture measurements, surface roughness standards, manufacture of micro and nano structured functional surfaces, replicated surfaces for optical applications (e.g. optical gratings), and process chains based on combinations of repeated surface replication steps....

  15. 石英光纤表面化学镀镍磷合金工艺%Electroless nickel-phosphor plating process on surface of quartz optical fiber

    Institute of Scientific and Technical Information of China (English)

    李小甫; 姜德生; 余海湖; 余丁山; 杨恩宇; 李鸿辉

    2005-01-01

    Quartz optical fibers are of great significance in many fields. For example, they can be used to fabricate strain sensors and temperature sensors. If the surface of optical fibers is metal-coated by the electroless plating method, the measuring precision and stability of the optical fiber sensors can be improved remarkably, additionally the life-span of sensors can be prolonged. In this work, an electroles snickel-phosphor plating process for optical fibers was presented. The influences of the content of NaH2PO2·H2O, bath pH value and temperature and the plating deposition rate on the quality of the plating coatings were studied with orthogonal testing. The results indicated that the content of NaH2PO2·H2O was the key factor, which influenced the adhesion force of the plating coatings. The nickel-phosphor plating bath presented in this work possessed excellent stability and the plating deposition rate could be accelerated. Using the process described in this work, nickel-phosphor coatings with great brightness and high adhesion force can be prepared successfully. Optimum conditions were: NiSO4 30g·L-1, NaH2PO2 ·H2O 20g·L-1, C3H6O3 4 ml·L-1, Na2CO3 3g·L-1 , NH4Cl 4g·L-1 , saccharin 1mg·L-1, temperature 84℃, pH 4.6.

  16. The application of nickel molybdate and nickel vanadates as photoanodes in a photoelectrochemical cell

    NARCIS (Netherlands)

    Haart, L.G.J. De; Blasse, G.

    1985-01-01

    The application of nickel molybdate, NiMoO4, and the nickel vanadates NiV2O6, Ni2V2O7 and Ni3V2O8 as photoanodes in a photoelectrochemical cell is investigated. Based on the optical and structural properties reported and discussed, NiV2O6 would be a good candidate, but attempts to prepare dense pell

  17. Response of nickel surface to pulsed fusion plasma radiations

    Science.gov (United States)

    Niranjan, Ram; Rout, R. K.; Srivastava, R.; Chakravarthy, Y.; Patel, N. N.; Alex, P.; Gupta, Satish C.

    2014-04-01

    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.

  18. Nickel-doped zinc aluminate oxides: starch-assisted synthesis, structural, optical properties, and their catalytic activity in oxidative coupling of methane

    Science.gov (United States)

    Visinescu, Diana; Papa, Florica; Ianculescu, Adelina C.; Balint, Ioan; Carp, Oana

    2013-03-01

    Nanosized nickel-substituted zinc aluminate oxides were obtained by the gradual insertion of nickel cations within the zinc aluminate lattice, using starch as active ingredient. The obtained (Ni x Zn1- x Al2)-starch ( x = 0.1, 0.2, 0.4, 0.6, 0.8, 1) gel precursors were characterized through infrared spectroscopy and thermal analysis. The thermal behavior of the precursors are influenced by the nickel content, the DTA curves for the richer nickel samples revealing stronger, faster and overlapping exothermic reactions, that can be completed at lower temperatures. The corresponding spinelic oxides were obtained after calcination treatments at 800 °C and analyzed by means of NIR-UV-Vis spectroscopy, XRD measurements, SEM, TEM, and HRTEM investigations. The spinelic structure for all oxide samples is confirmed by XRD analysis, although small amounts of NiO cannot be neglected. TEM/HRTEM analysis revealed mesopores embedded in plate-like large (68.8 nm) particles of Ni0.2Zn0.8Al2O4 sample and smaller (15.7 nm) uniform equiaxial particles, with a more pronounced tendency of agglomeration for Ni0.8Zn0.2Al2O4 oxide. A formation mechanism for Ni0.2Zn0.8Al2O4 oxides was proposed based on DTA/TG, XRD, and SEM analyses. NIR-UV-Vis spectra for Ni x Zn1- x Al2O4 showed a significant presence of tetrahedral nickel cations that augments with nickel concentration increase. CIE- L * a * b * color parameters shown a variation of the lightness and also of the green and blue color components with x, the best color characteristics being obtained for x = 0.6. The oxides with a substitution degree x = 0.2 and 0.8 tested in the oxidative coupled of methane reaction (OCM) showed positive catalytic activity and selectivity due to an interesting synergetic effect of Zn(II) and Ni(II) ions.

  19. 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.

  20. Nickel transfer by fingers.

    Science.gov (United States)

    Isnardo, D; Vidal, J; Panyella, D; Vilaplana, J

    2015-06-01

    We investigated fingers as a potential source of nickel transfer to the face in patients with allergic contact dermatitis to nickel and a history of facial dermatitis. Samples were collected from the fingers and cheeks of volunteers using the stripping method with standard adhesive tape, and nickel levels were quantified using mass spectrometry. Fingers and cheeks of individuals who had handled coins were both positive for nickel, with levels ranging from 14.67 to 58.64 ppm and 1.28 to 8.52 ppm, respectively. The levels in a control group were considerably and significantly lower. Transfer of nickel from a person's fingers to their face after handling a nickel-containing object could explain the presence of facial dermatitis in patients with nickel hypersensitivity.

  1. extraction-spectrophotometric determination of nickel at microgram ...

    African Journals Online (AJOL)

    a

    analysis of metal ions was combination of liquid extraction and ... A Jenway Model 6300 UV-Visible spectrophotometer (England) with a 1 cm optical ... In Job's method the amount of nickel in aqueous phase and MPMP in the organic phase.

  2. Perfluorodiethoxymethane on nickel and nickel oxide surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Jacobson, Joyce [Iowa State Univ., Ames, IA (United States)

    1994-03-03

    The interaction of perfluorodiethoxymethane with a nickel single crystal, Ni(100); a nickel crystal with chemisorbed oxygen, Ni(100)-c(2x2)O; and a nickel crystal with nickel oxide crystallites, NiO(100) is investigated in an ultra high vacuum environment using thermal desorption spectroscopy and high resolution electron energy loss spectroscopy. Nickel, a component of hard disk drives and stainless steel, is used to represent metal surfaces in these "real" systems. Perfluorodiethoxymethane is used in this study as a model compound of industrial perfluoropolyether lubricants. These lubricants are known for their exceptional stability, except in the presence of metals. Perfluorodiethoxymethane contains the acetal group (-OCF2O-), believed to be particularly vulnerable to attack in the presence of Lewis acids. Since the surfaces studied show increasing Lewis acidity at the nickel atom sites, one might expect to see increasing decomposition of perfluorodiethoxymethane due to acidic attack of the acetal group. No decomposition of perfluorodiethoxymethane is observed on the clean Ni(100) surface, while more research is needed to determine whether a small decomposition pathway is observed on the oxygenated surfaces, or whether sample impurities are interfering with results. The strength of the bonding of perfluorodiethoxymethane to the surface is found to increase as the nickel atoms sites become more acidic in moving from Ni(100) to Ni (100)-c(2x2)O to NiO (100).

  3. Simultaneous preconcentration of copper, zinc, cadmium, and nickel in water samples by cloud point extraction using 4-(2-pyridylazo)-resorcinol and their determination by inductively coupled plasma optic emission spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Edson Luiz, E-mail: edsonqmc@hotmail.com [Centro de Energia Nuclear na Agricultura, Universidade de Sao Paulo, Av. Centenario, 303, CP 96, 13416-000 Piracicaba, SP (Brazil); Santos Roldan, Paulo dos [Universidade Federal de Alagoas, Campus A.C. Simoes, Av. Lourival Melo Mota, Tabuleiro do Martins, CEP: 57072-970 AL (Brazil); Gine, Maria Fernanda [Centro de Energia Nuclear na Agricultura, Universidade de Sao Paulo, Av. Centenario, 303, CP 96, 13416-000 Piracicaba, SP (Brazil)

    2009-11-15

    A procedure for simultaneous separation/preconcentration of copper, zinc, cadmium, and nickel in water samples, based on cloud point extraction (CPE) as a prior step to their determination by inductively coupled plasma optic emission spectrometry (ICP-OES), has been developed. The analytes reacted with 4-(2-pyridylazo)-resorcinol (PAR) at pH 5 to form hydrophobic chelates, which were separated and preconcentrated in a surfactant-rich phase of octylphenoxypolyethoxyethanol (Triton X-114). The parameters affecting the extraction efficiency of the proposed method, such as sample pH, complexing agent concentration, buffer amount, surfactant concentration, temperature, kinetics of complexation reaction, and incubation time were optimized and their respective values were 5, 0.6 mmol L{sup -1}, 0.3 mL, 0.15% (w/v), 50 deg. C, 40 min, and 10 min for 15 mL of preconcentrated solution. The method presented precision (R.S.D.) between 1.3% and 2.6% (n = 9). The concentration factors with and without dilution of the surfactant-rich phase for the analytes ranged from 9.4 to 10.1 and from 94.0 to 100.1, respectively. The limits of detection (L.O.D.) obtained for copper, zinc, cadmium, and nickel were 1.2, 1.1, 1.0, and 6.3 {mu}g L{sup -1}, respectively. The accuracy of the procedure was evaluated through recovery experiments on aqueous samples.

  4. Simultaneous preconcentration of copper, zinc, cadmium, and nickel in water samples by cloud point extraction using 4-(2-pyridylazo)-resorcinol and their determination by inductively coupled plasma optic emission spectrometry.

    Science.gov (United States)

    Silva, Edson Luiz; Roldan, Paulo dos Santos; Giné, Maria Fernanda

    2009-11-15

    A procedure for simultaneous separation/preconcentration of copper, zinc, cadmium, and nickel in water samples, based on cloud point extraction (CPE) as a prior step to their determination by inductively coupled plasma optic emission spectrometry (ICP-OES), has been developed. The analytes reacted with 4-(2-pyridylazo)-resorcinol (PAR) at pH 5 to form hydrophobic chelates, which were separated and preconcentrated in a surfactant-rich phase of octylphenoxypolyethoxyethanol (Triton X-114). The parameters affecting the extraction efficiency of the proposed method, such as sample pH, complexing agent concentration, buffer amount, surfactant concentration, temperature, kinetics of complexation reaction, and incubation time were optimized and their respective values were 5, 0.6 mmol L(-1), 0.3 mL, 0.15% (w/v), 50 degrees C, 40 min, and 10 min for 15 mL of preconcentrated solution. The method presented precision (R.S.D.) between 1.3% and 2.6% (n=9). The concentration factors with and without dilution of the surfactant-rich phase for the analytes ranged from 9.4 to 10.1 and from 94.0 to 100.1, respectively. The limits of detection (L.O.D.) obtained for copper, zinc, cadmium, and nickel were 1.2, 1.1, 1.0, and 6.3 microg L(-1), respectively. The accuracy of the procedure was evaluated through recovery experiments on aqueous samples.

  5. Replicated Spectrographs in Astronomy

    CERN Document Server

    Hill, Gary J

    2014-01-01

    As telescope apertures increase, the challenge of scaling spectrographic astronomical instruments becomes acute. The next generation of extremely large telescopes (ELTs) strain the availability of glass blanks for optics and engineering to provide sufficient mechanical stability. While breaking the relationship between telescope diameter and instrument pupil size by adaptive optics is a clear path for small fields of view, survey instruments exploiting multiplex advantages will be pressed to find cost-effective solutions. In this review we argue that exploiting the full potential of ELTs will require the barrier of the cost and engineering difficulty of monolithic instruments to be broken by the use of large-scale replication of spectrographs. The first steps in this direction have already been taken with the soon to be commissioned MUSE and VIRUS instruments for the Very Large Telescope and the Hobby-Eberly Telescope, respectively. MUSE employs 24 spectrograph channels, while VIRUS has 150 channels. We compa...

  6. 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.

  7. Structural transformation of nickel hydroxide films during anodic oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Crocker, Robert W. [Univ. of California, Berkeley, CA (United States); Muller, Rolf H. [Univ. of California, Berkeley, CA (United States)

    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 - 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.

  8. Synthesis, spectroscopic studies and nonlinear optical behavior of N,N‧-bis(2-hydroxy-1-naphthylmethylidene)-1-methyl-1,2-diaminoethane-N,N‧,O,O‧-nickel(II)

    Science.gov (United States)

    Ünver, Hüseyin; Elmali, Ayhan; Karakaş, Aslı; Kara, Hülya; Donmez, Emine

    2006-12-01

    A Schiff base complex N, N'-bis(2-hydroxy-1-naphthylmethylidene)-1-methyl-1,2- diaminoethane- N, N', O, O'-nickel(II) has been synthesized. The title compound has been characterized by FT-IR and UV-vis spectroscopies. The UV-vis experiments indicate that the compound has solvatochromism in the UV region, implying non-zero molecular first hyperpolarizability. To investigate microscopic second-order nonlinear optical (NLO) behavior of the examined complex, the electric dipole moments ( μ) and the first static hyperpolarizabilities ( β) were computed using Finite Field second-order Møller Plesset (FF MP2) perturbation procedure. According to ab initio quantum mechanical calculations, the title complex exhibits non-zero β values, revealing microscopic second-order NLO behavior.

  9. Nickel doped zinc oxide nanoparticles produced by hydrothermal decomposition of nickel-doped zinc hydroxide nitrate

    Institute of Scientific and Technical Information of China (English)

    Mohammad Yeganeh Ghotbi

    2012-01-01

    Zinc hydroxide nitrate,an anionic exchanger layered material,undoped as well as doped with 2-10% nickel,was synthesized by using a pH-controlled precipitation method.The layered materials were then used to produce the undoped and nickel-doped zinc oxides by hydrothermal-treatment.X-ray diffraction,Fourier transform infrared spectroscopy and scanning electron microscopy confirmed the formation of pure phase undoped and nickel-doped layered materials,as well as the products of the hydrothermaltreated materials,nanostructured zinc oxides.Optical studies of the nanostructured zinc oxides showed a decrease in band gap with increasing content of the doping agent,nickel.

  10. Replication and dimensional quality control of industrial nanoscale surfaces using calibrated AFM measurements and SEM image processing

    DEFF Research Database (Denmark)

    Tosello, Guido; Hansen, Hans Nørgaard; Marinello, F.

    2010-01-01

    application of AFM to calibrate height, depth and pitch of sub-micrometer features and SEM image processing to detect replication accuracy in terms of number of replicated features. Surface replication is analyzed using a metrological approach: nano-features on nickel stampers and injection...

  11. Archaeal DNA replication.

    Science.gov (United States)

    Kelman, Lori M; Kelman, Zvi

    2014-01-01

    DNA replication is essential for all life forms. Although the process is fundamentally conserved in the three domains of life, bioinformatic, biochemical, structural, and genetic studies have demonstrated that the process and the proteins involved in archaeal DNA replication are more similar to those in eukaryal DNA replication than in bacterial DNA replication, but have some archaeal-specific features. The archaeal replication system, however, is not monolithic, and there are some differences in the replication process between different species. In this review, the current knowledge of the mechanisms governing DNA replication in Archaea is summarized. The general features of the replication process as well as some of the differences are discussed.

  12. Nickel Curie Point Engine

    Science.gov (United States)

    Chiaverina, Chris; Lisensky, George

    2014-01-01

    Ferromagnetic materials such as nickel, iron, or cobalt lose the electron alignment that makes them attracted to a magnet when sufficient thermal energy is added. The temperature at which this change occurs is called the "Curie temperature," or "Curie point." Nickel has a Curie point of 627 K, so a candle flame is a sufficient…

  13. The effects of thermomechanical history on the microstructure of a nickel-base superalloy during forging

    Energy Technology Data Exchange (ETDEWEB)

    Gardner, S., E-mail: 485354@swansea.ac.uk [College of Engineering, Bay Campus, Swansea University, Swansea SA1 8EN (United Kingdom); Li, W. [Rolls-Royce plc, PO Box 31, Derby DE24 8BJ (United Kingdom); Coleman, M. [College of Engineering, Bay Campus, Swansea University, Swansea SA1 8EN (United Kingdom); Johnston, R., E-mail: r.johnston@swansea.ac.uk [College of Engineering, Bay Campus, Swansea University, Swansea SA1 8EN (United Kingdom)

    2016-06-21

    The effect of thermo-mechanical history on hot compression behaviour and resulting microstructures of a nickel base superalloy is presented. Hot compression tests were carried out on HAYNES® 282® specimens to varying strains from 0.1 to 0.8. Both single pass and multi-pass tests were completed. 60 min inter-pass times were utilized to accurately replicate industrial forging practices. The effect of dynamic, metadynamic and static recrystallization during inter-pass times on flow stress was investigated. The resulting microstructures were analysed using scanning electron, optical microscopy and EBSD to relate grain size and homogeneity with flow stress data. The study showed a negligible difference between multi-pass and single pass tests for strain increments above 0.2. Therefore, when modelling similar low strain and strain rate forging processes in HAYNES® 282®, previous forging steps can be ignored.

  14. Fabrication, performance, and figure metrology of epoxy-replicated aluminum foils for hard x-ray focusing multilayer-coated segmented conical optics

    DEFF Research Database (Denmark)

    Jimenez-Garate, M.A.; Craig, W.W.; Hailey, C.J.;

    2000-01-01

    telescope HPD, we designed a figure metrology system and a new mounting technique. We describe a cylindrical metrology system built for fast axial and roundness figure measurement of hard x-ray conical optics. These developments lower cost and improve the optics performance of the HEFT (high-energy focusing...

  15. Fabrication, performance, and figure metrology of epoxy-replicated aluminum foils for hard x-ray focusing multilayer-coated segmented conical optics

    DEFF Research Database (Denmark)

    Jimenez-Garate, M.A.; Craig, W.W.; Hailey, C.J.

    2000-01-01

    telescope HPD, we designed a figure metrology system and a new mounting technique. We describe a cylindrical metrology system built for fast axial and roundness figure measurement of hard x-ray conical optics. These developments lower cost and improve the optics performance of the HEFT (high-energy focusing...

  16. Differential Deposition Technique for Figure Corrections in Grazing Incidence X-ray Optics

    Science.gov (United States)

    Kilaru, Kiranmayee; Ramsey, Brian D.; Gubarev, Mikhail

    2009-01-01

    A differential deposition technique is being developed to correct the low- and mid-spatial-frequency deviations in the axial figure profile of Wolter type grazing incidence X-ray optics. These deviations arise due to various factors in the fabrication process and they degrade the performance of the optics by limiting the achievable angular resolution. In the differential deposition technique, material of varying thickness is selectively deposited along the length of the optic to minimize these deviations, thereby improving the overall figure. High resolution focusing optics being developed at MSFC for small animal radionuclide imaging are being coated to test the differential deposition technique. The required spatial resolution for these optics is 100 m. This base resolution is achievable with the regular electroform-nickel-replication fabrication technique used at MSFC. However, by improving the figure quality of the optics through differential deposition, we aim at significantly improving the resolution beyond this value.

  17. 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

    2013-01-01

    Nickel dermatitis (skin allergy) is a growing problem in numerous countries. The alarming frequency of sensitization to nickel especially in the US caused nickel to be selected as the "Allergen of the Year" in 2008 by the American Contact Dermatitis Society. Nickel as coating in contact with skin...

  18. NICKEL – ENVIRONMENTAL ALLERGEN

    Directory of Open Access Journals (Sweden)

    Henryka Langauer-Lewowicka

    2010-06-01

    Full Text Available Nickel (Ni is ubiquitus in our biosphere because of its emission from natural and anthropogenic sources. Its toxic and carcinogenic properties are well recognised only in workers exposed to high Ni concentrations. Nickel allergy is the most common form of cutaneus hypersensitivity in general population and also in occupationally exposed groups. As sensitizing agent Ni has a high prevalence of allergic contact dermatitis. The most important known risk factor associated with nickel allergy is ear piercing and use of other jewelry in females. In general population 17 % adults and 8 % children have Ni allergy symptoms. Permanently growing Ni allergy is regarded as serious risk for public health.

  19. Effect of nickel salt precursors on morphology, size, optical property and type of products (NiSe or Se) in hydrothermal method

    Science.gov (United States)

    Salavati-Niasari, Masoud; Sobhani, Azam

    2013-03-01

    NiSe micro/nanocrystals with multiform morphologies, including particles, rods and flowers were prepared by hydrothermal method from different Ni salts: NiBr2, Ni(ClO4)2ṡ6H2O, NiCl2ṡ6H2O and NiSO4ṡ6H2O. Se nanorods were produced simply by varying the nickel salts to Ni(CH3COO)2ṡH2O and Ni(NO3)2ṡ6H2O. The process was performed at 180 °C for 12 h and cetyltrimethyl ammonium bromide (CTAB) and hydrazine hydrate (N2H4ṡH2O) used as surfactant and reductant, respectively. The samples were analyzed by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electronic diffraction (SAED) and X-ray energy dispersive spectroscopy (EDS). The synthesis was performed conveniently and safely.

  20. Effect of Thermal Annealing on the Structural and Optical Properties Nanostructured Cobalt-Manganese and Cobalt-Nickel Oxides Prepared by Co-Precipitation

    Science.gov (United States)

    Indulal, C. R.; Kumar, G. Sajeev; Vaidyan, A. V.; Raveendran, R.

    2011-10-01

    Cobalt-Manganese and Cobalt-Nickel oxide (CoMnO and CoNiO) nanoparticles were synthesized via chemical co-precipitation method by decomposition of their respective metal sulfides and sodium carbonate using ethylene diamene tetra acetic acid as the capping agent. The samples were heated at 400, 600 and 800 °C. The average particle sizes were determined from the X-ray line broadening. The diffractogram were compared with JCPDS data to identify the crystallographic phase and cubic structure of the particles. The samples were characterized by XRD, FTIR and UV analyses. The internal elastic micro strains were calculated and it was seen that as the particle size increases strain decreases. The FTIR studies have been used to confirm the metal oxide formation. The chemical compositions of the samples were verified using EDX spectra. The surface morphologies of the samples were studied from the SEM images. The absorption spectra of the materials in the UV-Vis-NIR range were recorded. From the analysis of the absorption spectra, the direct band gaps of the materials were calculated.

  1. Copper(II) and nickel(II) complexes of tetradentate Schiff base ligand: UV-Vis and FT-IR spectra and DFT calculation of electronic, vibrational and nonlinear optical properties

    Science.gov (United States)

    Zarei, Seyed Amir; Khaledian, Donya; Akhtari, Keivan; Hassanzadeh, Keyumars

    2015-11-01

    The experimental fourier transform infrared (FT-IR) and ultraviolet-visible (UV-Vis) spectra of copper(II) and nickel(II) complexes of the deprotonated tetradentate Schiff base ligand N,N‧-bis(2-hydroxybenzylidene)-2,2-dimethyl-1,3-propanediamine (H2L) are compared with their corresponding theoretical ones. The applied theoretical method is based on the density functional theory and time-dependent density functional theory at the UPBE0/PBE0 levels using Def2-TZVP basis set. The computational optimised geometric parameters of the complexes are in good agreement with their corresponding experimental data. The FT-IR and UV-Vis spectra of the complexes were reproduced on the basis of their optimised structures. The vibrational assignments of some fundamental modes of the complexes are performed. The highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energies are calculated. The analyses of the calculated electronic absorption spectra of the complexes are carried out to elucidate the electronic transitions assignments and their characters. Second-order nonlinear optical property of the complexes is evaluated by the above-mentioned theoretical method that implies much greater values for the complexes in comparison with the corresponding value of urea.

  2. 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.

  3. Replication Restart in Bacteria.

    Science.gov (United States)

    Michel, Bénédicte; Sandler, Steven J

    2017-07-01

    In bacteria, replication forks assembled at a replication origin travel to the terminus, often a few megabases away. They may encounter obstacles that trigger replisome disassembly, rendering replication restart from abandoned forks crucial for cell viability. During the past 25 years, the genes that encode replication restart proteins have been identified and genetically characterized. In parallel, the enzymes were purified and analyzed in vitro, where they can catalyze replication initiation in a sequence-independent manner from fork-like DNA structures. This work also revealed a close link between replication and homologous recombination, as replication restart from recombination intermediates is an essential step of DNA double-strand break repair in bacteria and, conversely, arrested replication forks can be acted upon by recombination proteins and converted into various recombination substrates. In this review, we summarize this intense period of research that led to the characterization of the ubiquitous replication restart protein PriA and its partners, to the definition of several replication restart pathways in vivo, and to the description of tight links between replication and homologous recombination, responsible for the importance of replication restart in the maintenance of genome stability. Copyright © 2017 American Society for Microbiology.

  4. Optical properties and switching durability of TiO2 top-coated magnesium-nickel thin-film switchable mirrors

    Science.gov (United States)

    Bao, Shanhu; Zhang, Xiaoli; Jin, Ping; Yoshimura, Kazuki

    2015-04-01

    An amorphous TiO2 film (180 nm) was deposited as a protective layer on the surface of a triple-layer thin-film switchable mirror (Pd/Ti/Mg4Ni deposited on glass) by a sol-gel coating process, and its optical switching behavior and switching lifetime under 4% hydrogen gas loading were evaluated. The use of a TiO2 coating extended the switching durability to about 1600 cycles, which is a fourfold increase compared with that of uncoated mirrors. The switching response of the Pd/Ti/Mg4Ni thin film was not affected by the presence of the TiO2 film, with hydrogenation and dehydrogenation speeds being almost the same as those of uncoated mirrors. The optical properties of the TiO2-coated mirrors were improved in the hydrogenated state, and a diffuse reflection phenomenon was observed in the dehydrogenated state.

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

    DEFF Research Database (Denmark)

    Tang, Peter Torben

    2001-01-01

    and material distribution is even more important. Using a bath consisting mostly of nickel chloride, pulse reversal plating of both pure nickel and nickel-cobalt alloys has been used to fabricate tools for micro-injection molding. Pulse reversal plating of ternary soft-magnetic alloys, comprising 45-65 percent...

  6. 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.

  7. Solar selective black nickel-cobalt coatings on aluminum alloys

    Energy Technology Data Exchange (ETDEWEB)

    Shashikala, A.R.; Sharma, A.K.; Bhandari, D.R. [Thermal System Group, ISRO Satellite Centre, Bangalore 560 017 (India)

    2007-04-16

    Solar selective black nickel-cobalt plating on pre cleaned aluminum alloy substrates with nickel undercoat were investigated. Process optimization was carried out by the hull cell experiments investigating the influence of operating variables on the optical selectivity of the coating. The coatings were characterized with scanning electron microscope, X-ray diffraction, energy dispersive X-ray spectroscopic and polarization studies. Evaluation of the coatings was carried out by adhesion, measurement of coating thickness and optical properties, humidity, thermal cycling, thermo-vacuum performance and thermal stability tests. (author)

  8. Synthesis, structural, optical band gap and biological studies on iron (III), nickel (II), zinc (II) and mercury (II) complexes of benzyl α-monoxime pyridyl thiosemicarbazone

    Science.gov (United States)

    Bedier, R. A.; Yousef, T. A.; Abu El-Reash, G. M.; El-Gammal, O. A.

    2017-07-01

    New ligand, (E)-2-((E)-2-(hydroxyimino)-1,2-diphenylethylidene)-N-(pyridin-2 yl) hydrazinecarbothioamide (H2DPPT) and its complexes [Fe(DPPT)Cl(H2O)], [Ni(H2DPPT)2Cl2], [Zn(HDPPT)(OAc)] and [Hg(HDPPT)Cl](H2O)4 were isolated and characterized by various of physico-chemical techniques. IR spectra show that H2DPPT coordinates to the metal ions as neutral NN bidentate, mononegative NNS tridentate and binegative NNSN tetradentate, respectively. From the modeling studies, the bond length, bond angle, HOMO, LUMO and dipole moment had been calculated to confirm the geometry of the ligands and their investigated complexes. The thermal studies showed the type of water molecules involved in metal complexes Furthermore, the kinetic and thermodynamic parameters for the different decomposition steps were calculated using the Coats-Redfern and Horowitz-Metzger methods. Also, the optical band gap (Eg) has been calculated to elucidate the conductivity of the isolated complexes. The optical transition energy (Eg) is direct and equals 3.34 and 3.44 ev for Ni and Fe complexes, respectively. The ligand and their metal complexes were screened for antibacterial activity against the following bacterial species, Bacillus thuringiensis, Staphylococcus aureus, Pseudomonas aeuroginosa and Escherichia coli. The results revealed that the metal complexes have more potent antibacterial compared with the ligand. Also, the degradation effect of the investigated compounds was tested showing that, Ni complex exhibited powerful and complete degradation effect on DNA.

  9. NICKEL-BASE ALLOY

    Science.gov (United States)

    Inouye, H.; Manly, W.D.; Roche, T.K.

    1960-01-19

    A nickel-base alloy was developed which is particularly useful for the containment of molten fluoride salts in reactors. The alloy is resistant to both salt corrosion and oxidation and may be used at temperatures as high as 1800 deg F. Basically, the alloy consists of 15 to 22 wt.% molybdenum, a small amount of carbon, and 6 to 8 wt.% chromium, the balance being nickel. Up to 4 wt.% of tungsten, tantalum, vanadium, or niobium may be added to strengthen the alloy.

  10. Optics

    CERN Document Server

    Fincham, W H A

    2013-01-01

    Optics: Ninth Edition Optics: Ninth Edition covers the work necessary for the specialization in such subjects as ophthalmic optics, optical instruments and lens design. The text includes topics such as the propagation and behavior of light; reflection and refraction - their laws and how different media affect them; lenses - thick and thin, cylindrical and subcylindrical; photometry; dispersion and color; interference; and polarization. Also included are topics such as diffraction and holography; the limitation of beams in optical systems and its effects; and lens systems. The book is recommen

  11. DNA replication and cancer

    DEFF Research Database (Denmark)

    Boyer, Anne-Sophie; Walter, David; Sørensen, Claus Storgaard

    2016-01-01

    A dividing cell has to duplicate its DNA precisely once during the cell cycle to preserve genome integrity avoiding the accumulation of genetic aberrations that promote diseases such as cancer. A large number of endogenous impacts can challenge DNA replication and cells harbor a battery of pathways...... causing DNA replication stress and genome instability. Further, we describe cellular and systemic responses to these insults with a focus on DNA replication restart pathways. Finally, we discuss the therapeutic potential of exploiting intrinsic replicative stress in cancer cells for targeted therapy....

  12. 2-Mercaptobenzimidazole, 2-Mercaptobenzothiazole, and Thioglycolic Acid in an Electroless Nickel-Plating Bath

    Directory of Open Access Journals (Sweden)

    Ahmet Ozan Gezerman

    2015-01-01

    Full Text Available The use of three different materials, 2-mercaptobenzimidazole, 2-mercaptobenzothiazole, and thioglycolic acid, was investigated to improve the performance of electroless nickel-plating baths. By changing the concentrations of these materials, sample plates were coated. Optical microscope images were obtained by selecting representative coated plates. From the results of the investigations, the effects of these materials on electroless nickel plating were observed, and the most appropriate amounts of these materials for nickel plating were determined. Moreover, the nickel plating speed observed with the bath solution containing 2-mercaptobenzimidazole, 2-mercaptobenzothiazole, and thioglycolic acid is higher than that in the case of traditional electroless plating baths, but the nickel consumption amount in the former case is lower. In order to minimize the waste water generated from electroless nickel-plating baths, we determined the lowest amounts of the chemicals that can be used for the concentrations reported in the literature.

  13. A Study On Dispersion Stability Of Nickel Nanoparticles Synthesized By Wire Explosion In Liquid Media

    Directory of Open Access Journals (Sweden)

    Kim C.K.

    2015-06-01

    Full Text Available In this study, nickel nanoparticles were synthesized in ethanol using portable pulsed wire evaporation, which is a one-step physical method. From transmission electron microscopy images, it was found that the Ni nanoparticles exhibited a spherical shape with an average diameter of 7.3 nm. To prevent aggregation of the nickel nanoparticles, a polymer surfactant was added into the ethanol before the synthesis of nickel nanoparticles, and adsorbed on the freshly synthesized nickel nanoparticles during the wire explosion. The dispersion stability of the prepared nickel nanofluids was investigated by zeta-potential analyzer and Turbiscan optical analyzer. As a result, the optimum concentration of polymer surfactant to be added was suggested for the maximized dispersion stability of the nickel nanofluids.

  14. 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...

  15. Iron induced nickel deficiency

    Science.gov (United States)

    It is increasingly apparent that economic loss due to nickel (Ni) deficiency likely occurs in horticultural and agronomic crops. While most soils contain sufficient Ni to meet crop requirements, situations of Ni deficiency can arise due to antagonistic interactions with other metals. This study asse...

  16. 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...

  17. cobalt (ii), nickel (ii)

    African Journals Online (AJOL)

    DR. AMINU

    ABSTRACT. The manganese (II), cobalt (II), nickel (II) and copper (II) complexes of N, N' – ... temperature and coordinated water were determined ... indicating fairly stable complex compounds (Table 1). The complex compounds are insoluble [Table 2] in water and common organic solvents, but are readily soluble in ...

  18. Multiwall carbon nanotube/nickel oxide nanocompositecoatings: Sol-gel deposition and characterization

    CSIR Research Space (South Africa)

    Roro, Kittessa T

    2011-09-01

    Full Text Available Due to their unique electronic and optical properties nanocomposite materials have wide range of applications in solar energy conversion. In this study, multiwalled carbon nanotubes (MWCNTs)/Nickel oxide (NiO) nanocomposites were successfully...

  19. Nickel Coatings and Electroforming Using Pulse Reversal Plating

    DEFF Research Database (Denmark)

    Tang, Peter Torben; Dylmer, Henrik; Møller, Per

    1995-01-01

    Introducing pulse plating brings new life and possibilities to one the oldest groups of electroplating processes. Nickel coatings and electroforming are used in a great variety of products, from oil valves to optical discs, and for many applications such as corrosion protection and micro-mechanic......Introducing pulse plating brings new life and possibilities to one the oldest groups of electroplating processes. Nickel coatings and electroforming are used in a great variety of products, from oil valves to optical discs, and for many applications such as corrosion protection and micro......-mechanics. A series of new results using pulse reversal plating in Watts based electrolytes will be discussed. Elec-troforming completely without internal stress and with improved throwing power will be demonstrated, as well as a corrosion resistance of nickel coatings that could allow coating thicknesses, as well...

  20. Synthesis, spectral, structural, second-order nonlinear optical properties and theoretical studies on new organometallic donor-acceptor substituted nickel(II) and copper(II) unsymmetrical Schiff-base complexes.

    Science.gov (United States)

    Trujillo, Alexander; Fuentealba, Mauricio; Carrillo, David; Manzur, Carolina; Ledoux-Rak, Isabelle; Hamon, Jean-René; Saillard, Jean-Yves

    2010-03-15

    The synthesis, spectroscopic and structural characterization, linear and nonlinear optical properties, as well as the electrochemical behavior of a series of robust neutral binuclear M[Fc-C(O)CH=C(CH(3))N-X-N=CH-(2-O,5-R-C(6)H(3))] (M = Ni (4), Cu (5), X = o-C(6)H(4), R = H; M = Ni (9), X = CH(2)CH(2), R = OH), and their corresponding ionic trinuclear [M{Fc-C(O)CH=C(CH(3))N-X-N=CH-(eta(6)-2-O,5-R-C(6)H(3))RuCp*}][PF(6)] (6, 7, 10), M[ONNO]-type unsymmetrical Salophen and salen complexes featuring ferrocenyl (Fc) donor and the mixed sandwich acceptor [Cp*Ru(eta(6)- salicylidene)](+) as a push-pull moiety are reported in this paper (Fc = CpFe(eta(5)-C(5)H(4)); Cp = eta(5)-C(5)H(5); Cp* = eta(5)-C(5)Me(5)). The single-crystal X-ray structure of the bimetallic iron-nickel derivative 4 indicates a bowed structure of the unsymmetrical Schiff base skeleton. The Ni(II) ion is tetracoordinated in a square planar environment, with two nitrogen atoms and two oxygen atoms as donors. The new metalloligand [Fc-C(O)CH=C(CH(3))N(H)CH(2)CH(2)N=CH-(2,5-(OH)(2)C(6)H(3))] (8) obtained from the Schiff base condensation of 2,5-dihydroxobenzaldehyde with the half-unit precursor, Fc-C(O)CH=C(CH(3))N(H)CH(2)CH(2)NH(2) (2), is reported with its crystal structure showing partial delocalization of the heteroconjugated [O-C-C-C-N] frameworks with a dihedral angle between the respective planes of 60.76 degrees. Second order nonlinear optical (NLO) measurements were achieved using the Harmonic Light Scattering technique to probe the role of the M[ONNO] chromophores and of the pi-complexation of the salicylidene ring in the nonlinearity. All the complexes exhibit a second-order nonlinear response increasing with the nuclearity, the hyperpolarizability (beta) value of the trinuclear complex 10 being 1.5 time larger than that of the metalloligand 8 (beta = 155 x 10(-30) esu). A rationalization of the structural, electronic, and redox properties of the title compounds is provided, based on a

  1. Spacetime replication of continuous variable quantum information

    Science.gov (United States)

    Hayden, Patrick; Nezami, Sepehr; Salton, Grant; Sanders, Barry C.

    2016-08-01

    The theory of relativity requires that no information travel faster than light, whereas the unitarity of quantum mechanics ensures that quantum information cannot be cloned. These conditions provide the basic constraints that appear in information replication tasks, which formalize aspects of the behavior of information in relativistic quantum mechanics. In this article, we provide continuous variable (CV) strategies for spacetime quantum information replication that are directly amenable to optical or mechanical implementation. We use a new class of homologically constructed CV quantum error correcting codes to provide efficient solutions for the general case of information replication. As compared to schemes encoding qubits, our CV solution requires half as many shares per encoded system. We also provide an optimized five-mode strategy for replicating quantum information in a particular configuration of four spacetime regions designed not to be reducible to previously performed experiments. For this optimized strategy, we provide detailed encoding and decoding procedures using standard optical apparatus and calculate the recovery fidelity when finite squeezing is used. As such we provide a scheme for experimentally realizing quantum information replication using quantum optics.

  2. Optics

    CERN Document Server

    Fincham, W H A

    2013-01-01

    Optics: Eighth Edition covers the work necessary for the specialization in such subjects as ophthalmic optics, optical instruments and lens design. The text includes topics such as the propagation and behavior of light; reflection and refraction - their laws and how different media affect them; lenses - thick and thin, cylindrical and subcylindrical; photometry; dispersion and color; interference; and polarization. Also included are topics such as diffraction and holography; the limitation of beams in optical systems and its effects; and lens systems. The book is recommended for engineering st

  3. Initial study of Nickel Electrolyte for EnFACE Process

    Directory of Open Access Journals (Sweden)

    Tri Widayatno

    2015-03-01

    Full Text Available Nickel electrolyte for a micro-pattern transfer process without photolithography, EnFACE, has been developed. Previous work on copper deposition indicated that a conductivity of ~2.7 Sm-1 is required. Electrochemical parameters of electrolyte i.e. current density and overpotential are also crucial to govern a successful pattern replication. Therefore, the investigation focused on the measurement of physicochemical properties and electrochemical behaviour of the electrolyte at different nickel concentrations and complexing agents of chloride and sulfamate. Nickel electrolytes containing sulfamate, chloride and combined sulfamate-chloride with concentrations between 0.14 M and 0.3 M were investigated. Physicochemical properties i.e. pH and conductivity were measured to ensure if they were in the desired value. The electrochemical behaviour of the electrolytes was measured by polarisation experiments in a standard three-electrode cell. The working electrode was a copper disc (surface area of 0.196 cm2 and the counter electrode was platinum mesh. The potential was measured againts a saturated calomel reference electrode (SCE. The experiments were carried out at various scan rate and Rotating Disc Electrode (RDE rotation speed to see the effect of scan rate and agitation. Based on the measured physicochemical properties, the electrolyte of 0.19 M nickel sulfamate was chosen for experimentation. Polarisation curve of agitated solution suggested that overall nickel electrodeposition reaction is controlled by a combination of kinetics and mass transfer.  Reduction potential of nickel was in the range of -0.7 to -1.0 V. The corresponding current densities for nickel deposition were in the range of -0.1 to -1.5 mA cm-2.

  4. Replicating animal mitochondrial DNA

    Directory of Open Access Journals (Sweden)

    Emily A. McKinney

    2013-01-01

    Full Text Available The field of mitochondrial DNA (mtDNA replication has been experiencing incredible progress in recent years, and yet little is certain about the mechanism(s used by animal cells to replicate this plasmid-like genome. The long-standing strand-displacement model of mammalian mtDNA replication (for which single-stranded DNA intermediates are a hallmark has been intensively challenged by a new set of data, which suggests that replication proceeds via coupled leading-and lagging-strand synthesis (resembling bacterial genome replication and/or via long stretches of RNA intermediates laid on the mtDNA lagging-strand (the so called RITOLS. The set of proteins required for mtDNA replication is small and includes the catalytic and accessory subunits of DNA polymerase y, the mtDNA helicase Twinkle, the mitochondrial single-stranded DNA-binding protein, and the mitochondrial RNA polymerase (which most likely functions as the mtDNA primase. Mutations in the genes coding for the first three proteins are associated with human diseases and premature aging, justifying the research interest in the genetic, biochemical and structural properties of the mtDNA replication machinery. Here we summarize these properties and discuss the current models of mtDNA replication in animal cells.

  5. 49 CFR 173.198 - Nickel carbonyl.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Nickel carbonyl. 173.198 Section 173.198... Nickel carbonyl. (a) Nickel carbonyl must be packed in specification steel or nickel cylinders as prescribed for any compressed gas except acetylene. A cylinder used exclusively for nickel carbonyl may...

  6. 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. © 2015 Wiley Periodicals, Inc.

  7. The effects of different nickel concentrations on some morpho-physiological characteristics of parsley (Petroselinum crispum

    Directory of Open Access Journals (Sweden)

    mitra khatib

    2009-06-01

    Full Text Available Nickel as a heavy metal is considered a fatal and toxic element for humans, animals and plants. However, some plants are known as hyper accumulator for nickel and sometimes seem to be useful for plant growth. Thus, investigation on the effect of nickel on plants' growth is an issue of importance. In this paper, we have studied the effect of different nickel concentrations on parsley growth and morph-physiological characteristics and its effect on absorption of some macro elements in this plant. Seeds of parsley were germinated in germinator and seedlings were transferred to hydroponics culture. The seedlings were grown in Hogland solution with different nickel concentrations (in form of nickel nitrate of: 0, 0.25, 0.5, 0.75, 1, 1.5, 2 and 4 ppm. A completely randomized design with 8 treatments and 7 replications per treatment was used. Twelve weeks after treatments, morph-physiological characteristics including SPAD number, plant biomass, length of shoot and root, leaf area, leaf number and stomatal resistance were measured. The amount of absorbed nickel in plant foliages and roots of different treatments were also measured. The results revealed that the application of different nickel concentrations were decreased SPAD number, plant biomass, leaf area and leaf number, but the stomatal resistance were increased. Increase of nickel concentration resulted increasing Ni concentrations of plant foliages and roots. Nickel with 0.75 ppm concentration or higher imposed a toxic effect on parsley as general wilting and significant reduction in most morph-physiological characteristics. Keywords: Hydroponics culture, parsley, Petroselinum crispum, Nickel.

  8. The Replication Recipe: What makes for a convincing replication?

    NARCIS (Netherlands)

    Brandt, M.J.; IJzerman, H.; Dijksterhuis, A.J.; Farach, F.J.; Geller, J.; Giner-Sorolla, R.; Grange, J.A.; Perugini, M.; Spies, J.R.; Veer, A. van 't

    2014-01-01

    Psychological scientists have recently started to reconsider the importance of close replications in building a cumulative knowledge base; however, there is no consensus about what constitutes a convincing close replication study. To facilitate convincing close replication attempts we have developed

  9. 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.

  10. Submicron Composite Mirror Replication (PDRT08-027) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR program will identify and address the primary technical issues that limit the current precision of replicated CFRP optics. These issues must be resolved to...

  11. Modeling DNA Replication.

    Science.gov (United States)

    Bennett, Joan

    1998-01-01

    Recommends the use of a model of DNA made out of Velcro to help students visualize the steps of DNA replication. Includes a materials list, construction directions, and details of the demonstration using the model parts. (DDR)

  12. Eukaryotic DNA Replication Fork.

    Science.gov (United States)

    Burgers, Peter M J; Kunkel, Thomas A

    2017-06-20

    This review focuses on the biogenesis and composition of the eukaryotic DNA replication fork, with an emphasis on the enzymes that synthesize DNA and repair discontinuities on the lagging strand of the replication fork. Physical and genetic methodologies aimed at understanding these processes are discussed. The preponderance of evidence supports a model in which DNA polymerase ε (Pol ε) carries out the bulk of leading strand DNA synthesis at an undisturbed replication fork. DNA polymerases α and δ carry out the initiation of Okazaki fragment synthesis and its elongation and maturation, respectively. This review also discusses alternative proposals, including cellular processes during which alternative forks may be utilized, and new biochemical studies with purified proteins that are aimed at reconstituting leading and lagging strand DNA synthesis separately and as an integrated replication fork.

  13. Lightweight Electrode For Nickel/Hydrogen Cell

    Science.gov (United States)

    Britton, Doris L.

    1994-01-01

    Improved substrate for nickel electrode increases specific energy of nickel/hydrogen cell. Consists of 50 percent by weight nickel fiber, 35 percent nickel powder, and 15 percent cobalt powder. Porosity and thickness of nickel electrodes affect specific energy, initial performance, and cycle life of cell. Substrate easily manufactured with much larger porosities than those of heavy-sintered state-of-art nickel substrate.

  14. The accumulation of nickel in human lungs.

    OpenAIRE

    Edelman, D A; Roggli, V L

    1989-01-01

    Using data from published studies, lung concentrations of nickel were compare for persons with and without occupational exposure to nickel. As expected, the concentrations were much higher for persons with occupational exposure. To estimate the effects of nickel-containing tobacco smoke and nickel in the ambient air on the amount of nickel accumulated in lungs over time, a model was derived that took into account various variables related to the deposition of nickel in lungs. The model predic...

  15. Abiotic self-replication.

    Science.gov (United States)

    Meyer, Adam J; Ellefson, Jared W; Ellington, Andrew D

    2012-12-18

    The key to the origins of life is the replication of information. Linear polymers such as nucleic acids that both carry information and can be replicated are currently what we consider to be the basis of living systems. However, these two properties are not necessarily coupled. The ability to mutate in a discrete or quantized way, without frequent reversion, may be an additional requirement for Darwinian evolution, in which case the notion that Darwinian evolution defines life may be less of a tautology than previously thought. In this Account, we examine a variety of in vitro systems of increasing complexity, from simple chemical replicators up to complex systems based on in vitro transcription and translation. Comparing and contrasting these systems provides an interesting window onto the molecular origins of life. For nucleic acids, the story likely begins with simple chemical replication, perhaps of the form A + B → T, in which T serves as a template for the joining of A and B. Molecular variants capable of faster replication would come to dominate a population, and the development of cycles in which templates could foster one another's replication would have led to increasingly complex replicators and from thence to the initial genomes. The initial genomes may have been propagated by RNA replicases, ribozymes capable of joining oligonucleotides and eventually polymerizing mononucleotide substrates. As ribozymes were added to the genome to fill gaps in the chemistry necessary for replication, the backbone of a putative RNA world would have emerged. It is likely that such replicators would have been plagued by molecular parasites, which would have been passively replicated by the RNA world machinery without contributing to it. These molecular parasites would have been a major driver for the development of compartmentalization/cellularization, as more robust compartments could have outcompeted parasite-ridden compartments. The eventual outsourcing of metabolic

  16. Adenovirus DNA Replication

    OpenAIRE

    Hoeben, Rob C.; Uil, Taco G.

    2013-01-01

    Adenoviruses have attracted much attention as probes to study biological processes such as DNA replication, transcription, splicing, and cellular transformation. More recently these viruses have been used as gene-transfer vectors and oncolytic agents. On the other hand, adenoviruses are notorious pathogens in people with compromised immune functions. This article will briefly summarize the basic replication strategy of adenoviruses and the key proteins involved and will deal with the new deve...

  17. 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 administration...... of 5.6 mg nickel (as the sulfate), increased nickel excretion was found over the following 2-3 days. We conclude that consecutive urinary nickel determinations are able to disclose variations in oral intake of nickel....

  18. Electrolytic Recovery of Nickel from Spent Electroless Nickel Bath Solution

    Directory of Open Access Journals (Sweden)

    R. Idhayachander

    2010-01-01

    Full Text Available Plating industry is one of the largest polluting small scale industries and nickel plating is among the important surface finishing process in this industry. The waste generated during this operation contains toxic nickel. Nickel removal and recovery is of great interest from spent bath for environmental and economic reasons. Spent electroless nickel solution from a reed relay switch manufacturing industry situated in Chennai was taken for electrolytic recovery of nickel. Electrolytic experiment was carried out with mild steel and gold coated mild steel as cathode and the different parameters such as current density, time, mixing and pH of the solution were varied and recovery and current efficiency was studied. It was noticed that there was an increase in current efficiency up to 5 A/dm2 and after that it declines. There is no significant improvement with mixing but with modified cathode there was some improvement. Removal of nickel from the spent electroless nickel bath was 81.81% at 5 A/dm2 and pH 4.23. Under this condition, the content of nickel was reduced to 0.94 g/L from 5.16 g/L. with 62.97% current efficiency.

  19. Nickel release from nickel-plated metals and stainless steels.

    Science.gov (United States)

    Haudrechy, P; Foussereau, J; Mantout, B; Baroux, B

    1994-10-01

    Nickel release from nickel-plated metals often induces allergic contact dermatitis, but, for nickel-containing stainless steels, the effect is not well-known. In this paper, AISI 304, 316L, 303 and 430 type stainless steels, nickel and nickel-plated materials were investigated. 4 tests were performed: patch tests, leaching experiments, dimethylglyoxime (DMG) spot tests and electrochemical tests. Patch tests showed that 96% of the patients were intolerant to Ni-plated samples, and 14% to a high-sulfur stainless steel (303), while nickel-containing stainless steels with a low sulfur content elicited no reactions. Leaching experiments confirmed the patch tests: in acidic artificial sweat, Ni-plated samples released about 100 micrograms/cm2/week of nickel, while low-sulfur stainless steels released less than 0.03 microgram/cm2/week of nickel, and AISI 303 about 1.5 micrograms/cm2/week. Attention is drawn to the irrelevance of the DMG spot test, which reveals Ni present in the metal bulk but not its dissolution rate. Electrochemical experiments showed that 304 and 316 grades remain passive in the environments tested, while Ni-plated steels and AISI 303 can suffer significant cation dissolution. Thus, Ni-containing 304 and 316 steels should not induce contact dermatitis, while 303 should be avoided. A reliable nitric acid spot test is proposed to distinguish this grade from other stainless steels.

  20. Removal of nickel from spent electroless nickel-plating bath with nickel foam cathode

    Institute of Scientific and Technical Information of China (English)

    于秀娟; 郑彤; 魏杰; 周定

    2002-01-01

    The electrochemical method was used to remove nickel ion from spent electroless nickel plating bath(pH = 5.3). An electrolytic cell was composed of a porous nickel foam cathode and an inert RuO2/Ti anode.Nickel ions were reduced and deposited on the surface of the nickel foam cathode. The effect of current density(i), linear velocity of wastewater (v), gap between cathode and anode (dc/A) and reaction time (t) on nickelremoval rate and current efficiency were studied. As reaction time prolonged, nickel removal rate increasedwhile current efficiency decreased. And larger v and smaller dc/A can enhance nickel removal rate and increasecurrent efficiency by promoting mass transfer and dropping concentration polarization. The effect of current den-sity on nickel removal by electrochemistry was related to other parameters. After three hours' electrolysis withi = 1.0 A/dm2, v = 18.5 cm/min and dc/A = 0. 5 cm, nickel removal rate and current efficiency reached85.6% and 29. 1%, respectively.

  1. Minichromosome replication in vitro: inhibition of re-replication by replicatively assembled nucleosomes.

    Science.gov (United States)

    Krude, T; Knippers, R

    1994-08-19

    Single-stranded circular DNA, containing the SV40 origin sequence, was used as a template for complementary DNA strand synthesis in cytosolic extracts from HeLa cells. In the presence of the replication-dependent chromatin assembly factor CAF-1, defined numbers of nucleosomes were assembled during complementary DNA strand synthesis. These minichromosomes were then induced to semiconservatively replicate by the addition of the SV40 initiator protein T antigen (re-replication). The results indicate that re-replication of minichromosomes appears to be inhibited by two independent mechanisms. One acts at the initiation of minichromosome re-replication, and the other affects replicative chain elongation. To directly demonstrate the inhibitory effect of replicatively assembled nucleosomes, two types of minichromosomes were prepared: (i) post-replicative minichromosomes were assembled in a reaction coupled to replication as above; (ii) pre-replicative minichromosomes were assembled independently of replication on double-stranded DNA. Both types of minichromosomes were used as templates for DNA replication under identical conditions. Replicative fork movement was found to be impeded only on post-replicative minichromosome templates. In contrast, pre-replicative minichromosomes allowed one unconstrained replication cycle, but re-replication was inhibited due to a block in fork movement. Thus, replicatively assembled chromatin may have a profound influence on the re-replication of DNA.

  2. Discussion of "Normal Spectral Emissivity Measurement of Liquid Iron and Nickel Using Electromagnetic Levitation in Direct Current Magnetic Field."

    Science.gov (United States)

    Daun, Kyle J.

    2016-07-01

    This note corrects nonphysical Drude model parameters presented for molten iron and nickel. A comparison of the corrected Drude models with data published in the literature shows that a simple Drude form is inadequate to describe the optical properties of molten iron and nickel.

  3. Nickel, cobalt, and their alloys

    CERN Document Server

    2000-01-01

    This book is a comprehensive guide to the compositions, properties, processing, performance, and applications of nickel, cobalt, and their alloys. It includes all of the essential information contained in the ASM Handbook series, as well as new or updated coverage in many areas in the nickel, cobalt, and related industries.

  4. Nickel: Impact on horticultural characteristics

    Science.gov (United States)

    Knowledge by practitioners regarding the potential impact of nickel nutritional physiology on pecan orchard profitability is a limiting factor in optimization of physiological efficiency of orchard enterprises. Knowledge by farmers and extension specialists about the role of nickel, a newly recogni...

  5. Nickel: Relevance to orchard profitability

    Science.gov (United States)

    The nutritional physiology of essential micronutrients in pecan, especially that of nickel, is a limiting factor in optimization of physiological efficiency of orchard enterprises. Knowledge by farmers and extension specialists about the role of nickel, a newly recognized micronutrient, is meager. ...

  6. The cost of nickel allergy

    DEFF Research Database (Denmark)

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

    2013-01-01

    Federation, Japan, and Mexico, one-third or more of the denominations released nickel. Conclusions. This worldwide selection of circulating coins covered countries with 75% of the world population, and shows that the majority of the world population lives in countries where coins release nickel. Pertinently...

  7. Characterization and assessment of dermal and inhalable nickel exposures in nickel production and primary user industries.

    Science.gov (United States)

    Hughson, G W; Galea, K S; Heim, K E

    2010-01-01

    The aim of this study was to measure the levels of nickel in the skin contaminant layer of workers involved in specific processes and tasks within the primary nickel production and primary nickel user industries. Dermal exposure samples were collected using moist wipes to recover surface contamination from defined areas of skin. These were analysed for soluble and insoluble nickel species. Personal samples of inhalable dust were also collected to determine the corresponding inhalable nickel exposures. The air samples were analysed for total inhalable dust and then for soluble, sulfidic, metallic, and oxidic nickel species. The workplace surveys were carried out in five different workplaces, including three nickel refineries, a stainless steel plant, and a powder metallurgy plant, all of which were located in Europe. Nickel refinery workers involved with electrolytic nickel recovery processes had soluble dermal nickel exposure of 0.34 microg cm(-2) [geometric mean (GM)] to the hands and forearms. The GM of soluble dermal nickel exposure for workers involved in packing nickel salts (nickel chloride hexahydrate, nickel sulphate hexahydrate, and nickel hydroxycarbonate) was 0.61 microg cm(-2). Refinery workers involved in packing nickel metal powders and end-user powder operatives in magnet production had the highest dermal exposure (GM = 2.59 microg cm(-2) soluble nickel). The hands, forearms, face, and neck of these workers all received greater dermal nickel exposure compared with the other jobs included in this study. The soluble nickel dermal exposures for stainless steel production workers were at or slightly above the limit of detection (0.02 microg cm(-2) soluble nickel). The highest inhalable nickel concentrations were observed for the workers involved in nickel powder packing (GM = 0.77 mg m(-3)), although the soluble component comprised only 2% of the total nickel content. The highest airborne soluble nickel exposures were associated with refineries using

  8. Investigating variation in replicability: A "Many Labs" replication project

    NARCIS (Netherlands)

    Klein, R.A.; Ratliff, K.A.; Vianello, M.; Adams, R.B.; Bahnik, S.; Bernstein, M.J.; Bocian, K.; Brandt, M.J.; Brooks, B.; Brumbaugh, C.C.; Cemalcilar, Z.; Chandler, J.; Cheong, W.; Davis, W.E.; Devos, T.; Eisner, M.; Frankowska, N.; Furrow, D.; Galliani, E.M.; Hasselman, F.W.; Hicks, J.A.; Hovermale, J.F.; Hunt, S.J.; Huntsinger, J.R.; IJzerman, H.; John, M.S.; Joy-Gaba, J.A.; Kappes, H.B.; Krueger, L.E.; Kurtz, J.; Levitan, C.A.; Mallett, R.K.; Morris, W.L.; Nelson, A.J.; Nier, J.A.; Packard, G.; Pilati, R.; Rutchick, A.M.; Schmidt, K.; Skorinko, J.L.M.; Smith, R.; Steiner, T.G.; Storbeck, J.; Van Swol, L.M.; Thompson, D.; Veer, A.E. van 't; Vaughn, L.A.; Vranka, M.; Wichman, A.L.; Woodzicka, J.A.; Nosek, B.A.

    2014-01-01

    Although replication is a central tenet of science, direct replications are rare in psychology. This research tested variation in the replicability of 13 classic and contemporary effects across 36 independent samples totaling 6,344 participants. In the aggregate, 10 effects replicated consistently.

  9. Hepatitis B virus replication

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Hepadnaviruses, including human hepatitis B virus (HBV), replicate through reverse transcription of an RNA intermediate, the pregenomic RNA (pgRNA). Despite this kinship to retroviruses, there are fundamental differences beyond the fact that hepadnavirions contain DNA instead of RNA. Most peculiar is the initiation of reverse transcription: it occurs by protein-priming, is strictly committed to using an RNA hairpin on the pgRNA,ε, as template, and depends on cellular chaperones;moreover, proper replication can apparently occur only in the specialized environment of intact nucleocapsids.This complexity has hampered an in-depth mechanistic understanding. The recent successful reconstitution in the test tube of active replication initiation complexes from purified components, for duck HBV (DHBV),now allows for the analysis of the biochemistry of hepadnaviral replication at the molecular level. Here we review the current state of knowledge at all steps of the hepadnaviral genome replication cycle, with emphasis on new insights that turned up by the use of such cellfree systems. At this time, they can, unfortunately,not be complemented by three-dimensional structural information on the involved components. However, at least for the s RNA element such information is emerging,raising expectations that combining biophysics with biochemistry and genetics will soon provide a powerful integrated approach for solving the many outstanding questions. The ultimate, though most challenging goal,will be to visualize the hepadnaviral reverse transcriptase in the act of synthesizing DNA, which will also have strong implications for drug development.

  10. Psychology, replication & beyond.

    Science.gov (United States)

    Laws, Keith R

    2016-06-01

    Modern psychology is apparently in crisis and the prevailing view is that this partly reflects an inability to replicate past findings. If a crisis does exists, then it is some kind of 'chronic' crisis, as psychologists have been censuring themselves over replicability for decades. While the debate in psychology is not new, the lack of progress across the decades is disappointing. Recently though, we have seen a veritable surfeit of debate alongside multiple orchestrated and well-publicised replication initiatives. The spotlight is being shone on certain areas and although not everyone agrees on how we should interpret the outcomes, the debate is happening and impassioned. The issue of reproducibility occupies a central place in our whig history of psychology.

  11. Nickel-hydrogen cell reversal characteristics

    Science.gov (United States)

    Lurie, Charles

    1994-01-01

    Nickel-hydrogen cell reversal characteristics are being studied as part of a TRW program directed towards development of a high current battery cell bypass switch. The following are discussed: cell bypass switch; nickel-hydrogen cell reversal characteristics; and nickel-hydrogen cell chemistry: discharge/reversal and overdischarge (reversal) with nickel and hydrogen precharge.

  12. Nickel-Free Alternatives Raise Awareness.

    Science.gov (United States)

    Hill, Hannah; Goldenberg, Alina; Sheehan, Michael Patrick; Patel, Amy; Jacob, Sharon E

    2015-01-01

    Allergic contact dermatitis to nickel is a global health problem. Worldwide, nickel continues to be the most prevalent and relevant contact allergen detected in tested populations for the last 30 years. Thus, the need for nickel-free products is palpable. We present a sustainable resource to aid providers and consumers in locating a wide variety of nickel free alternatives.

  13. DNA replication origins in archaea

    OpenAIRE

    Zhenfang eWu; Jingfang eLiu; Haibo eYang; Hua eXiang

    2014-01-01

    DNA replication initiation, which starts at specific chromosomal site (known as replication origins), is the key regulatory stage of chromosome replication. Archaea, the third domain of life, use a single or multiple origin(s) to initiate replication of their circular chromosomes. The basic structure of replication origins is conserved among archaea, typically including an AT-rich unwinding region flanked by several conserved repeats (origin recognition box, ORB) that are located adjacent to ...

  14. Improvement of replication fidelity in injection moulding of nano structures using an induction heating system

    DEFF Research Database (Denmark)

    Menotti, Stefano; Hansen, Hans Nørgaard; Bissacco, Giuliano

    2014-01-01

    In today’s industry, applications involving surface pattering with sub-μm scale structures have shown a high interest. The replication of these structures by injection molding leads to special requirements for the mold in order to ensure proper replication and an acceptable cycle time. A tool...... quantitatively characterized by atomic force microscopy comparing the measurement in the nickel insert with the corresponding polymer nano-features. The experimental results show that the use of the induction heating system is an efficient way to improve the pattern replication....

  15. Improvement of replication fidelity in injection moulding of nano structures using an induction heating system

    DEFF Research Database (Denmark)

    Menotti, Stefano; Hansen, Hans Nørgaard; Bissacco, Giuliano

    2014-01-01

    In today’s industry, applications involving surface pattering with sub-μm scale structures have shown a high interest. The replication of these structures by injection molding leads to special requirements for the mold in order to ensure proper replication and an acceptable cycle time. A tool ins...... quantitatively characterized by atomic force microscopy comparing the measurement in the nickel insert with the corresponding polymer nano-features. The experimental results show that the use of the induction heating system is an efficient way to improve the pattern replication....

  16. 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.

  17. Replication studies in longevity

    DEFF Research Database (Denmark)

    Varcasia, O; Garasto, S; Rizza, T

    2001-01-01

    In Danes we replicated the 3'APOB-VNTR gene/longevity association study previously carried out in Italians, by which the Small alleles (less than 35 repeats) had been identified as frailty alleles for longevity. In Danes, neither genotype nor allele frequencies differed between centenarians and 20...

  18. Replication-Fork Dynamics

    NARCIS (Netherlands)

    Duderstadt, Karl E.; Reyes-Lamothe, Rodrigo; van Oijen, Antoine M.; Sherratt, David J.

    2014-01-01

    The proliferation of all organisms depends on the coordination of enzymatic events within large multiprotein replisomes that duplicate chromosomes. Whereas the structure and function of many core replisome components have been clarified, the timing and order of molecular events during replication re

  19. Coronavirus Attachment and Replication

    Science.gov (United States)

    1988-03-28

    synthesis during RNA replication of vesicular stomatitis virus. J. Virol. 49:303-309. Pedersen, N.C. 1976a. Feline infectious peritonitis: Something old...receptors on intestinal brush border membranes from normal host species were developed for canine (CCV), feline (FIPV), porcine (TGEV), human (HCV...gastroenteritis receptor on pig BBMs ...... ................. ... 114 Feline infectious peritonitis virus receptor on cat BBMs ... .............. 117 Human

  20. 21 CFR 184.1537 - Nickel.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Nickel. 184.1537 Section 184.1537 Food and Drugs... Substances Affirmed as GRAS § 184.1537 Nickel. (a) Elemental nickel (CAS Reg. No. 7440-02-0) is obtained from nickel ore by transforming it to nickel sulfide (Ni3S2). The sulfide is roasted in air to give...

  1. Synthesis and characterization of nickel oxide (NiO) thin films

    Science.gov (United States)

    Kate, R. S.; Khalate, S. A.; Deokate, R. J.

    2017-05-01

    Nickel Oxide (NiO) thin films were deposited by simple spray pyrolysis technique using nickel nitrate solution onto preheated glass substrate at substrate temperature 320 °C and 380 °C. Influence of substrate temperature on structural, morphological and optical properties were studied using X-ray diffraction, scanning electron microscopy and optical absorption. XRD results reveal that films are polycrystalline with single phase cubic structure and crystallinity of the film increases as the temperature increases. Surface morphological study shows spherical granular like shape at high deposition temperature. Optical band gap increases from 2.85 to 3.01 eV as the temperature increases.

  2. Capacity fade in nickel cadmium and nickel hydrogen cells

    Science.gov (United States)

    Edgar, Tim; Hayden, Jeff; Pickett, David F.; Abrams-Blakemore, Bruce; Liptak, ED

    1993-01-01

    Research and operational experience with capacity fade in nickel cadmium and nickel hydrogen cells are summarized in outline form. The theoretical causes of capacity fade are reviewed and the role of cell storage, positive electrodes, and cobalt additives are addressed. Three examples of observed capacity fade are discussed: INTELSAT 5, INTELSAT 6, and an Explorer platform. Finally, prevention and recovery methods are addressed and the current status of Eagle Picher/Hughes research is discussed.

  3. Recent Progress in Adjustable X-ray Optics for Astronomy

    Science.gov (United States)

    Reid, Paul B.; Allured, Ryan; Cotroneo, Vincenzo; McMuldroch, Stuart; Marquez, Vanessa; Schwartz, Daniel A.; Vikhlinin, Alexey; ODell, Stephen L.; Ramsey, Brian; Trolier-McKinstry, Susan; hide

    2014-01-01

    Two adjustable X-ray optics approaches are being developed for thin grazing incidence optics for astronomy. The first approach employs thin film piezoelectric material sputter deposited as a continuous layer on the back of thin, lightweight Wolter-I mirror segments. The piezoelectric material is used to correct mirror figure errors from fabrication, mounting/alignment, and any ground to orbit changes. The goal of this technology is to produce Wolter mirror segment pairs corrected to 0.5 arc sec image resolution. With the combination of high angular resolution and lightweight, this mirror technology is suitable for the Square Meter Arc Second Resolution Telescope for X-rays (SMART-X) mission concept.. The second approach makes use of electrostrictive adjusters and full shell nickel/cobalt electroplated replication mirrors. An array of radial adjusters is used to deform the full shells to correct the lowest order axial and azimuthal errors, improving imaging performance from the 10 - 15 arc sec level to 5 arc sec. We report on recent developments in both technologies. In particular, we discuss the use of insitu strain gauges on the thin piezo film mirrors for use as feedback on piezoelectric adjuster functionality, including their use for on-orbit figure correction. We also report on the first tests of full shell nickel/cobalt mirror correction with radial adjusters.

  4. Reversible Switching of Cooperating Replicators

    Science.gov (United States)

    Urtel, Georg C.; Rind, Thomas; Braun, Dieter

    2017-02-01

    How can molecules with short lifetimes preserve their information over millions of years? For evolution to occur, information-carrying molecules have to replicate before they degrade. Our experiments reveal a robust, reversible cooperation mechanism in oligonucleotide replication. Two inherently slow replicating hairpin molecules can transfer their information to fast crossbreed replicators that outgrow the hairpins. The reverse is also possible. When one replication initiation site is missing, single hairpins reemerge from the crossbreed. With this mechanism, interacting replicators can switch between the hairpin and crossbreed mode, revealing a flexible adaptation to different boundary conditions.

  5. 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;

    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....

  6. 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;

    2011-01-01

    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.......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...

  7. Nickel-Magnesia Cermet Coatings

    Science.gov (United States)

    1952-06-01

    alumin " oxide cermet. To develop a bond between these tw components it in first necessary to produce a controlled film of Cr 203 on the Cr grains...somewhat more refractory. A cobalt - magnesia cermet may be made in the same way as the nickel - magnesia cermet, the bond being through the agency...of the oxide CoO. However, cobalt is not as oxidation resistant as nickel and is more strategic. Iron will wet probably all oxides and silicates and

  8. Low-cost replication of self-organized sub-micron structures into polymer films

    Directory of Open Access Journals (Sweden)

    H. Stenberg

    2015-02-01

    Full Text Available In this paper, the results of exploiting self-organized sub-micron polystyrene (PS wrinkle patterns possessing random orientation, in preparation of a nickel stamp for hot embossing purposes, are presented. Self-organized patterns were prepared employing a method in which a stiff cross-linked capping layer on the topmost part of the soft polystyrene layer was created by using reactive ion etching (RIE device with mild conditions and argon as a process gas, and the wrinkle formation was initiated thermally. Different surface patternings were obtained using silicon and stainless steel (SST wafers as substrates. Prepared Ni-stamps were employed in hot embossing of polycarbonate (PC and cyclo-olefin polymer (COP films, using a nano-imprinting process. The replication quality of the self-organized wrinkle structures in PC and COP films was monitored by comparing the shape and dimensions of the original and final surface structures. The hot embossed sub-micron scale features, originally formed on stainless steel substrate, were found to have influence on the optical properties of the PC and COP films by lowering their reflectances.

  9. Relationship between nickel allergy and diet

    Directory of Open Access Journals (Sweden)

    Sharma Ashimav

    2007-01-01

    Full Text Available 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 general population. Nickel content in food may vary considerably from place to place due to the difference in nickel content of the soil. However, certain foods are routinely high in nickel content. Nickel in the diet of a nickel-sensitive person can provoke dermatitis. Careful selection of food with relatively low nickel concentration can bring a reduction in the total dietary intake of nickel per day. This can influence the outcome of the disease and can benefit the nickel sensitive patient.

  10. XPS study of silver, nickel and bimetallic silver-nickel nanoparticles prepared by seed-mediated growth

    Energy Technology Data Exchange (ETDEWEB)

    Prieto, Pilar, E-mail: pilar.prieto@uam.es [Departamento de Fisica Aplicada and Instituto de Ciencia de Materiales ' Nicolas Cabrera' , Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Nistor, Valentin [Departamento de Fisica Aplicada and Instituto de Ciencia de Materiales ' Nicolas Cabrera' , Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Nouneh, Khalid [Institute for Nanomaterials and Nanotechnology (INANOTECH), Moroccan Foundation for Advanced Science, Innovation and Research (MAScIR), ENSET, Av. Armee Royale, 10100, Rabat (Morocco); Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8520 (Japan); Oyama, Munetaka [Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8520 (Japan); Abd-Lefdil, Mohammed [Laboratory of Materials Physics, University Mohammed V-Agdal, Rabat (Morocco); Diaz, Raquel [Departamento de Fisica Aplicada and Instituto de Ciencia de Materiales ' Nicolas Cabrera' , Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain)

    2012-09-01

    Highlights: Black-Right-Pointing-Pointer We have prepared Ag, Ni and AgNi NPs by derived seed-mediated growth method. Black-Right-Pointing-Pointer The combined use of optical, structural and chemical characterization techniques allows to determine the presence of core-shell structures. Black-Right-Pointing-Pointer The oxidation states of Ag and Ni at the outer layers of the NPs have been studied by XPS. Black-Right-Pointing-Pointer Ag NPs are purely metallic with a fcc structure. Black-Right-Pointing-Pointer Ni NPs are formed by Ni core-NiO + Ni(OH){sub 2} shell structure. Black-Right-Pointing-Pointer Ag core-NiO + Ni(OH){sub 2} shell structure is determined for AgNi NPs, with oxidized silver atoms at the interface. - Abstract: The chemical structure of silver, nickel and bimetallic silver-nickel nanoparticles, i.e. Ag, Ni and AgNi NPs, with sizes {<=}35 nm, obtained by derived seed-mediated growth method on transparent and conductive indium tin oxide (ITO) substrates, has been studied by a comparative X-ray photoelectron spectroscopy (XPS) analysis of Ag 3d, Ni 2p and O1s core levels in combination with X-ray diffraction and optical absorption spectroscopy in the visible range. XPS indicates that the surface of Ag NPs is not oxidized, while Ni NPs are clearly oxidized to nickel oxide and hydroxide. Absorptions at 384 and 600 nm in Ni optical spectrum are consistent with the presence of nickel in oxidized state; however the presence of metallic Ni 2p signal in Ni XPS spectrum indicates that a metallic nickel core is still present. In the case of bimetallic AgNi NPs, the XPS results are consistent with the presence of metallic silver core surrounded by NiO + Ni(OH){sub 2} shell. XPS spectra also show the presence of Ag{sub 2}O at the interface between the Ag metallic core and the oxidized nickel shell. XRD patterns of AgNi and Ag NPs show the typical fcc structure of metallic silver, confirming the presence of Ag metallic core in AgNi NPs. The surface plasmon

  11. Standard Specification for Copper-Aluminum-Silicon-Cobalt Alloy, Copper-Nickel-Silicon-Magnesium Alloy, Copper-Nickel-Silicon Alloy, Copper-Nickel-Aluminum-Magnesium Alloy, and Copper-Nickel-Tin Alloy Sheet and Strip

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2015-01-01

    Standard Specification for Copper-Aluminum-Silicon-Cobalt Alloy, Copper-Nickel-Silicon-Magnesium Alloy, Copper-Nickel-Silicon Alloy, Copper-Nickel-Aluminum-Magnesium Alloy, and Copper-Nickel-Tin Alloy Sheet and Strip

  12. Experiments shed new light on nickel-fluorine reactions

    Science.gov (United States)

    Fischer, J.; Gunther, W.; Jarry, R. L.

    1967-01-01

    Isotopic tracer experiments and scale-impingement experiments show fluorine to be the migrating species through the nickel fluoride scale formed during the fluorination of nickel. This is in contrast to nickel oxide scales, where nickel is the migrating species.

  13. Chromatin replication and epigenome maintenance

    DEFF Research Database (Denmark)

    Alabert, Constance; Groth, Anja

    2012-01-01

    initiates, whereas the replication process itself disrupts chromatin and challenges established patterns of genome regulation. Specialized replication-coupled mechanisms assemble new DNA into chromatin, but epigenome maintenance is a continuous process taking place throughout the cell cycle. If DNA...

  14. Chromatin replication and epigenome maintenance

    DEFF Research Database (Denmark)

    Alabert, Constance; Groth, Anja

    2012-01-01

    initiates, whereas the replication process itself disrupts chromatin and challenges established patterns of genome regulation. Specialized replication-coupled mechanisms assemble new DNA into chromatin, but epigenome maintenance is a continuous process taking place throughout the cell cycle. If DNA...

  15. Initiation of adenovirus DNA replication.

    OpenAIRE

    Reiter, T; Fütterer, J; Weingärtner, B; Winnacker, E L

    1980-01-01

    In an attempt to study the mechanism of initiation of adenovirus DNA replication, an assay was developed to investigate the pattern of DNA synthesis in early replicative intermediates of adenovirus DNA. By using wild-type virus-infected cells, it was possible to place the origin of adenovirus type 2 DNA replication within the terminal 350 to 500 base pairs from either of the two molecular termini. In addition, a variety of parameters characteristic of adenovirus DNA replication were compared ...

  16. Chromatin replication and epigenome maintenance

    DEFF Research Database (Denmark)

    Alabert, Constance; Groth, Anja

    2012-01-01

    Stability and function of eukaryotic genomes are closely linked to chromatin structure and organization. During cell division the entire genome must be accurately replicated and the chromatin landscape reproduced on new DNA. Chromatin and nuclear structure influence where and when DNA replication...... initiates, whereas the replication process itself disrupts chromatin and challenges established patterns of genome regulation. Specialized replication-coupled mechanisms assemble new DNA into chromatin, but epigenome maintenance is a continuous process taking place throughout the cell cycle. If DNA...

  17. Replication Research and Special Education

    Science.gov (United States)

    Travers, Jason C.; Cook, Bryan G.; Therrien, William J.; Coyne, Michael D.

    2016-01-01

    Replicating previously reported empirical research is a necessary aspect of an evidence-based field of special education, but little formal investigation into the prevalence of replication research in the special education research literature has been conducted. Various factors may explain the lack of attention to replication of special education…

  18. Replication Research and Special Education

    Science.gov (United States)

    Travers, Jason C.; Cook, Bryan G.; Therrien, William J.; Coyne, Michael D.

    2016-01-01

    Replicating previously reported empirical research is a necessary aspect of an evidence-based field of special education, but little formal investigation into the prevalence of replication research in the special education research literature has been conducted. Various factors may explain the lack of attention to replication of special education…

  19. Replication data collection highlights value in diversity of replication attempts

    Science.gov (United States)

    DeSoto, K. Andrew; Schweinsberg, Martin

    2017-01-01

    Researchers agree that replicability and reproducibility are key aspects of science. A collection of Data Descriptors published in Scientific Data presents data obtained in the process of attempting to replicate previously published research. These new replication data describe published and unpublished projects. The different papers in this collection highlight the many ways that scientific replications can be conducted, and they reveal the benefits and challenges of crucial replication research. The organizers of this collection encourage scientists to reuse the data contained in the collection for their own work, and also believe that these replication examples can serve as educational resources for students, early-career researchers, and experienced scientists alike who are interested in learning more about the process of replication. PMID:28291224

  20. 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.

  1. Anatomy of Mammalian Replication Domains

    Science.gov (United States)

    Takebayashi, Shin-ichiro; Ogata, Masato; Okumura, Katsuzumi

    2017-01-01

    Genetic information is faithfully copied by DNA replication through many rounds of cell division. In mammals, DNA is replicated in Mb-sized chromosomal units called “replication domains.” While genome-wide maps in multiple cell types and disease states have uncovered both dynamic and static properties of replication domains, we are still in the process of understanding the mechanisms that give rise to these properties. A better understanding of the molecular basis of replication domain regulation will bring new insights into chromosome structure and function. PMID:28350365

  2. Ultrafast stimulated emission and structural dynamics in nickel porphyrins.

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, X.; Wasinger, E. C.; Muresan, A. Z.; Attenkofer, K.; Jennings, G.; Lindsey, J. S.; Chen, L. X.; North Carolina State U.

    2007-11-22

    The excited-state structural dynamics of nickel(II)tetrakis(2,4,6-trimethylphenyl)porphyrin (NiTMP) and nickel(II)tetrakis(tridec-7-yl)porphyrin (NiSWTP) in a toluene solution were investigated via ultrafast transient optical absorption spectroscopy. An ultrashort stimulated emission between 620 and 670 nm from the S{sub 1} state was observed in both nickel porphyrins only when this state was directly generated via Q-band excitation, whereas such a stimulated emission was absent under B (Soret)-band excitation. Because the stimulated emission in the spectral region occurs only from the S{sub 1} state, this photoexcitation-wavelength-dependent behavior of Ni(II) porphyrins is attributed to a faster intersystem crossing from the S{sub 2} state than the internal conversion S{sub 2} {yields} S{sub 1}. The dynamics of the excited-state pathways involving the ({pi}, {pi}*) and (d, d) states varies with the meso-substituted peripheral groups, which is attributed to the nickel porphyrin macrocycle distortion from a planar configuration. Evidence for intramolecular vibrational relaxation within 2 ps and vibrational cooling in 6-20 ps of a (d, d) excited state has been established for NiTMP and NiSWTP. Finally, the lifetimes of the vibrationally relaxed (d, d) state also depend on the nature of the peripheral groups, decreasing from 200 ps for NiTMP to 100 ps for the bulkier NiSWTP.

  3. Flat Absorber Phosphorous Black Nickel Coatings for Space Applications

    Institute of Scientific and Technical Information of China (English)

    V. Maria Shalini; P. Arockiasamy; R. Urna Rani; A.K. Sharma

    2012-01-01

    A new process of flat absorber black nickel alloy coating tion from a bath containing nickel, zinc and ammonium was developed on stainless steel by electrodeposi- sulphates; thiocyanate and sodium hypophosphite for space applications. Coating process was optimized by investigating the effects of plating parameters, viz concentration of bath constituents, current density, temperature, pH and plating time on the optical properties of the black deposits. Energy dispersive X-ray spectroscopy showed the inclusion of about 6% phosphorous in the coating. The scanning electron microscopy studies revealed the amorphous nature of the coating. The corrosion resistance of the coatings was evaluated by the electrochemical impedance spectroscopy (EIS) and linear polarization (LP) techniques. The results revealed that, phosphorous addition confers better corro- sion resistance in comparison to conventional black nickel coatings. The black nickel coating obtained from hypophosphite bath provides high solar absorptance (αs) and infrared emittance (εIR) of the order of 0.93. Environmental stability to space applications was established by the humidity and thermal cycling tests.

  4. Growth kinetics of boride layers formed on 99.0% purity nickel

    Indian Academy of Sciences (India)

    I Gunes; K Keddam; R Chegroune; M Ozcatal

    2015-08-01

    The present study reports on the kinetics of borided Nickel 201 alloy. The thermochemical treatment of boronizing was carried out in a solid medium consisting of B4C and KBF4 powders mixture at 1123, 1173 and 1223 K for 2, 4 and 6 h, respectively. The boride layer was characterized by optical microscopy, X-ray diffraction technique and micro-Vickers hardness tester. X-ray diffraction analysis revealed the existence of NiB, Ni2B, Ni3B and Ni4B3 compounds at the surface of borided Nickel 201 alloy. The thickness of the boride layer increased with an increase in the boriding time and the temperature. The hardness of the nickel borides formed on the surface of the nickel substrate ranged from 1642 to 1854 HV0.05, whereas the Vickers hardness value of the untreated nickel was 185 HV0.05. The growth kinetics of boride layers forming on the borided Nickel 201 alloy was also analysed. The boron activation energy () was estimated as equal to 203.87 kJ mol−1 for the borided Nickel 201 alloy.

  5. Nickel and cobalt allergy before and after nickel regulation--evaluation of a public health intervention.

    Science.gov (United States)

    Thyssen, Jacob Pontoppidan

    2011-09-01

    Over the 20th century, the frequent use of nickel in consumer products resulted in an increasing prevalence of nickel allergy. Risk items included suspenders in the 1950s-1960s; buttons, zippers and rivets in the 1970s; and ear-piercing jewellery in the 1980s. When subjects allergic to nickel were exposed to nickel in high concentrations, it often resulted in allergic nickel contact dermatitis and hand eczema. In 1990, the Danish government began to regulate consumer nickel exposure as a response to the increasing nickel allergy problem. In 1994, the EU Nickel Directive was passed, a regulation that was based on the Danish and Swedish nickel regulations. These major public health interventions were expected to change the epidemiology of nickel allergy and dermatitis in Europe. Furthermore, it was debated whether nickel would be replaced by cobalt in inexpensive jewellery and result in higher prevalence of cobalt allergy. An evaluation of the possible effects of the European nickel regulations is of importance to ensure protection of consumers and dermatitis patients. This doctoral thesis aimed to evaluate the effects of regulatory interventions on nickel exposure by investigating the development of nickel allergy and dermatitis before and after nickel regulation. Furthermore, a change in the association between nickel allergy and hand eczema was evaluated. The nickel spot test was validated to determine its value when used for screening purposes. Possible explanations for the persistence of nickel allergy were explored including genetic predisposition and consumer nickel exposure from jewellery and accessories. A cobalt spot test was developed and validated. Finally, it was evaluated whether a cobalt allergy epidemic had replaced the nickel allergy epidemic after nickel regulation in terms of increasing cobalt sensitization and cobalt exposure. The thesis showed that the prevalence of nickel allergy decreased significantly after nickel regulation in young Danish

  6. The effects of platinum on nickel electrodes in the nickel hydrogen cell

    Science.gov (United States)

    Zimmerman, Albert H.

    1991-01-01

    Interactions of platinum and platinum compounds with the nickel electrode that are possible in the nickel hydrogen cell, where both the nickel electrode and a platinum catalyst hydrogen electrode are in intimate contact with the alkaline electrolyte, are examined. Additionally, a mechanism of nickel cobalt oxyhydroxide formation in NiH2 cells is presented.

  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...... additive. This method makes it possible to deposit nickel, cobalt, nickel or cobalt platings without internal stresses....

  8. Nickel and nickel-phosphorous matrix composite electrocoatings

    Institute of Scientific and Technical Information of China (English)

    Nicolas SPYRELLIS; Evangelia A. PAVLATOU; Styliani SPANOU; Alexandros ZOIKIS-KARATHANASIS

    2009-01-01

    Nickel and nickel-phosphorous matrix composite coatings reinforced by TiO2, SiC and WC particles were produced under direct and pulse current conditions from an additive-free Watts' type bath. The influence of the variable electrolysis parameters (type of current, frequency of current pulses and current density) and the reinforcing particles properties (type, size and concentration in the bath) on the surface morphology and the structure of the deposits was examined. It is demonstrated that the embedding of ceramic particles modifies in various ways the nickel electrocrystallisation process. On the other hand, Ni-P amorphous matrix is not affected by the occlusion of the particles. Overall, the imposition of pulse current conditions leads to composite coatings with increased embedded percentage and more homogenous distribution of particles in the matrix than coatings produced under direct current regime.

  9. 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.

  10. Nickel-responsive transcriptional regulators.

    Science.gov (United States)

    Musiani, Francesco; Zambelli, Barbara; Bazzani, Micaela; Mazzei, Luca; Ciurli, Stefano

    2015-09-01

    Nickel is an essential micronutrient for a large number of living organisms, but it is also a toxic metal ion when it accumulates beyond the sustainable level as it may result if and when its cellular trafficking is not properly governed. Therefore, the homeostasis and metabolism of nickel is tightly regulated through metal-specific protein networks that respond to the available Ni(II) concentration. These are directed by specific nickel sensors, able to couple Ni(II) binding to a change in their DNA binding affinity and/or specificity, thus translating the cellular level of Ni(II) into a modification of the expression of the proteins devoted to modulating nickel uptake, efflux and cellular utilization. This review describes the Ni(II)-dependent transcriptional regulators discovered so far, focusing on their structural features, metal coordination modes and metal binding thermodynamics. Understanding these properties is essential to comprehend how these sensors correlate nickel availability to metal coordination and functional responses. A broad and comparative study, described here, reveals some general traits that characterize the binding stoichiometry and Ni(II) affinity of these metallo-sensors.

  11. Modeling inhomogeneous DNA replication kinetics.

    Directory of Open Access Journals (Sweden)

    Michel G Gauthier

    Full Text Available In eukaryotic organisms, DNA replication is initiated at a series of chromosomal locations called origins, where replication forks are assembled proceeding bidirectionally to replicate the genome. The distribution and firing rate of these origins, in conjunction with the velocity at which forks progress, dictate the program of the replication process. Previous attempts at modeling DNA replication in eukaryotes have focused on cases where the firing rate and the velocity of replication forks are homogeneous, or uniform, across the genome. However, it is now known that there are large variations in origin activity along the genome and variations in fork velocities can also take place. Here, we generalize previous approaches to modeling replication, to allow for arbitrary spatial variation of initiation rates and fork velocities. We derive rate equations for left- and right-moving forks and for replication probability over time that can be solved numerically to obtain the mean-field replication program. This method accurately reproduces the results of DNA replication simulation. We also successfully adapted our approach to the inverse problem of fitting measurements of DNA replication performed on single DNA molecules. Since such measurements are performed on specified portion of the genome, the examined DNA molecules may be replicated by forks that originate either within the studied molecule or outside of it. This problem was solved by using an effective flux of incoming replication forks at the model boundaries to represent the origin activity outside the studied region. Using this approach, we show that reliable inferences can be made about the replication of specific portions of the genome even if the amount of data that can be obtained from single-molecule experiments is generally limited.

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

    Science.gov (United States)

    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 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.

  13. 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

    In July 2001, the EU Nickel Directive came into full force to protect European citizens against nickel allergy and dermatitis. Prior to this intervention, Northern European governments had already begun to regulate consumer nickel exposure. According to part 2 of the EU Nickel Directive...... and the Danish nickel regulation, consumer items intended to be in direct and prolonged contact with the skin were not allowed to release more than 0.5 µg nickel/cm2/week. It was considered unlikely that nickel allergy would disappear altogether as a proportion of individuals reacted below the level defined...... by 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 effect...

  14. The Deactivation of Nickel Hydroxide to Hypophosphite Electrooxidation on a Nickel Electrode

    Institute of Scientific and Technical Information of China (English)

    Yue ZENG; Min MO; Jian Long YI; Xin Jun TANG; Hui Xian WANG

    2004-01-01

    The deactivation of nickel hydroxide to the electrooxidation of hypophosphite on a nickel electrode was studied by means of in situ UV-Vis subtractive reflectance spectroscopy. The experimental results show that when the potential is lower than -1.0 V (SCE), the surface on nickel electrode is free of nickel hydroxide, on which hypophosphite is active. When the potential moves positively to about-0.75V, two absorbency bands around 300 nm and 550 nm, which were ascribed to the formation of α-nickel hydroxide, were observed, nickel is oxidized to α-nickel hydroxide.Severe deactivation of the surface occurs when the nickel surface is covered with nickel hydroxide,which separates the hypophosphite ion from nickel substrate.

  15. 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

    and the Danish nickel regulation, consumer items intended to be in direct and prolonged contact with the skin were not allowed to release more than 0.5 µg nickel/cm2/week. It was considered unlikely that nickel allergy would disappear altogether as a proportion of individuals reacted below the level defined......In July 2001, the EU Nickel Directive came into full force to protect European citizens against nickel allergy and dermatitis. Prior to this intervention, Northern European governments had already begun to regulate consumer nickel exposure. According to part 2 of the EU Nickel Directive...... by 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 effect...

  16. 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...... following the use of an Apple laptop computer (4). To estimate nickel release from Apple laptop computers, we investigated a random sample of 20 devices....

  17. 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....

  18. Surface micro topography replication in injection moulding

    DEFF Research Database (Denmark)

    Arlø, Uffe Rolf

    , the topography itself, and other factors were also investigated. The experimental work is based on a multi-purpose experimental injection mould with a collection of test surface inserts manufactured by EDM (electrical discharge machining). Experimental production took place with an injection moulding machine......Thermoplastic injection moulding is a widely used industrial process that involves surface generation by replication. The surface topography of injection moulded plastic parts can be important for aesthetical or technical reasons. With the emergence of microengineering and nanotechnology additional...... in a clean room environment. The mould and the injection moulding machine were fitted with transducers for subsequent process analysis. A total of 13 different plastic material grades were applied. Topographical characterisation was performed with an optical laser focus detection instrument. Replication...

  19. Development of process technologies for improvement of electroless nickel coatings properties

    Science.gov (United States)

    Barba-Pingarrón, A.; Bolarín-Miró, A.; Sánchez – de Jesús, F.; Vargas-Mendoza, L.; Trujillo-Barragán, M.; Molera-Sola, P.; Hernandez-Gallegos, M. A.; Valdez-Navarro, R.

    2013-06-01

    This paper describes research and technology developments that enable to improve nickel electroless coating properties. This work deals with: (a) different methods in order to achieve Ni-P-Mo coatings. (b) Other development is related with coatings with addition of hard particles such as SiC, WC or Al2O3,(c) Electroless nickel deposits on PBT and austempered ductile iron (ADI). (d) In addition, nickel coatings were deposited on powder metallic pieces and finally, electroless nickel coatings, in conjunction with layers from thermal spray process were formed. Characterization of all coatings by means of optical microscopy, scanning electron microscopy, micro-hardness, wear and corrosion tests were carried out. Results indicate positive increment in both mechanical and electrochemical properties which enhance field applications in Mexican industry.

  20. High performance transparent conductor of graphene wrapped copper/nickel microgrids

    Science.gov (United States)

    Wu, Wei; Tassi, Nancy G.; Walls, Dennis J.; Zhang, Lei; Willner, Bruce

    2014-12-01

    A high performance, highly stable transparent conducting structure based on microscale copper/nickel grids wrapped with graphene is presented. Graphene is selectively deposited on the surfaces of the microgrids by atmospheric pressure chemical vapor deposition method. The optical transmittance of the copper/nickel microgrid sample is ˜80% over the visible and near-infrared spectra with a very small sheet resistance of ˜0.58 Ω/sq. After the high temperature deposition of graphene, the sample's transmittance increases to be ˜90% due to the line width reduction of the microgrids while the sheet resistance also increases to ˜5 Ω/sq. The graphene layer is deposited to keep the copper/nickel surfaces from being oxidized in the air. Both stability testing and composition spectra results confirm the long-term stability of the copper/nickel microgrids wrapped with graphene.

  1. Chemical Capping Synthesis of Nickel Oxide Nanoparticles and their Characterizations Studies

    CERN Document Server

    rifaya, M Nowsath; Alagar, M; 10.5923/j.nn.20120205.01

    2012-01-01

    This work reports aspect related to chemical capping synthesis of nano-sized particles of nickel oxide. It is a simple, novel and cost effective method. The average particle size, specific surface area, crystallinity index are estimated from XRD analysis. The structural, functional groups and optical characters are analyzed with using of SEM, FTIR and UV- visible techniques. XRD studies confirm the presence of high degree of crystallinity nature of nickel oxide nanoparticles. Their particle size is found to be 12 nm and specific surface area (SSA) is 74m2 g-1. The optical band gap energy value 3.83ev has also been determined from UV-vis spectrum.

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

    Energy Technology Data Exchange (ETDEWEB)

    Jinlong, Lv, E-mail: ljlbuaa@126.com [Beijing Key Laboratory of Fine Ceramics, Institute of Nuclear and New Energy Technology, Tsinghua University, Zhongguancun Street, Haidian District, Beijing 100084 (China); State Key Lab of New Ceramic and Fine Processing, Tsinghua University, Beijing 100084 (China); Tongxiang, Liang; Chen, Wang [Beijing Key Laboratory of Fine Ceramics, Institute of Nuclear and New Energy Technology, Tsinghua University, Zhongguancun Street, Haidian District, Beijing 100084 (China); State Key Lab of New Ceramic and Fine Processing, Tsinghua University, Beijing 100084 (China)

    2016-03-15

    Graphical abstract: - Highlights: • Improved HER efficiency of Ni-Mo coatings was attributed to ‘cauliflower’ like microstructure. • RGO in nickel-RGO composite coating promoted refined grain and facilitated HER. • Synergistic effect between nickel and RGO facilitated HER due to large specific surface of RGO. - Abstract: 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 H{sub 2}SO{sub 4} 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 H{sub 2}SO{sub 4} 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.

  3. SUMO and KSHV Replication

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Pei-Ching [Institute of Microbiology and Immunology, National Yang-Ming University, Taipei 112, Taiwan (China); Kung, Hsing-Jien, E-mail: hkung@nhri.org.tw [Institute for Translational Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei 110, Taiwan (China); Department of Biochemistry and Molecular Medicine, University of California, Davis, CA 95616 (United States); UC Davis Cancer Center, University of California, Davis, CA 95616 (United States); Division of Molecular and Genomic Medicine, National Health Research Institutes, 35 Keyan Road, Zhunan, Miaoli County 35053, Taiwan (China)

    2014-09-29

    Small Ubiquitin-related MOdifier (SUMO) modification was initially identified as a reversible post-translational modification that affects the regulation of diverse cellular processes, including signal transduction, protein trafficking, chromosome segregation, and DNA repair. Increasing evidence suggests that the SUMO system also plays an important role in regulating chromatin organization and transcription. It is thus not surprising that double-stranded DNA viruses, such as Kaposi’s sarcoma-associated herpesvirus (KSHV), have exploited SUMO modification as a means of modulating viral chromatin remodeling during the latent-lytic switch. In addition, SUMO regulation allows the disassembly and assembly of promyelocytic leukemia protein-nuclear bodies (PML-NBs), an intrinsic antiviral host defense, during the viral replication cycle. Overcoming PML-NB-mediated cellular intrinsic immunity is essential to allow the initial transcription and replication of the herpesvirus genome after de novo infection. As a consequence, KSHV has evolved a way as to produce multiple SUMO regulatory viral proteins to modulate the cellular SUMO environment in a dynamic way during its life cycle. Remarkably, KSHV encodes one gene product (K-bZIP) with SUMO-ligase activities and one gene product (K-Rta) that exhibits SUMO-targeting ubiquitin ligase (STUbL) activity. In addition, at least two viral products are sumoylated that have functional importance. Furthermore, sumoylation can be modulated by other viral gene products, such as the viral protein kinase Orf36. Interference with the sumoylation of specific viral targets represents a potential therapeutic strategy when treating KSHV, as well as other oncogenic herpesviruses. Here, we summarize the different ways KSHV exploits and manipulates the cellular SUMO system and explore the multi-faceted functions of SUMO during KSHV’s life cycle and pathogenesis.

  4. Nickel electrode for alkaline batteries

    Energy Technology Data Exchange (ETDEWEB)

    Charkey, A.; Januszkiewicz, S.

    1985-10-08

    A nickel electrode including a conductive support and a layer on the support including a mixture of a nickel active material and a graphite diluent containing a spinel type oxide, the spinel type oxide having the formula M/sub 2/Co/sub 2/O/sub 4/, where M/sub 2/ is Co, Ni, Mn, Fe, Cu, Zn or Cd, or combinations thereof, and having a weight which is in the range of 1-30 percent of the weight of the diluent.

  5. 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

  6. Development, processing and fabrication of a nickel based nickel-chromium-iron alloy

    Science.gov (United States)

    Akinlade, Dotun Adebayo

    produced by P/M processing. The microstructure of the alloys was characterized by X-ray diffractometer (XRD), optical microscope (OM) and scanning electron microscope (SEM) equipped with energy dispersive spectrometer (EDS) and then compared with the thermodynamic predictions. It was observed that the experimental results matched reasonably closely with the thermodynamic predictions in terms of the phases present when Al was added to the ternary alloy, but not the volume fraction of the phases present in the microstructure. It was also observed by SEM image and quantitative EDS analysis that the optimum amount of well distributed Ni3Al phase formed when the concentration of aluminium was 6w/o. These results suggest that despite potential problems encountered in high temperature powder processing of Superalloys that often tend to influence the feasibility of using thermodynamic predictions to model such alloy systems, the software and predictions used in this study offer a way to simulate both design and characterisation of the experimental alloy. To characterize the phases that formed in the 6w/o Al modified ternary Ni-Cr-Fe alloy during heating to the sintering temperature, a differential scanning calorimetric study was carried out to study sequence of phase transformations, their reaction modes and products on heating a green compact from room temperature to the sintering temperature of 1300°C. Two different heating rates were employed for the DSC study, 2.5°C/min and 10°C/min. Transformation reactions were also studied by heating the samples in a DSC to the points of exo/endothermicity and quenching in argon followed by phase identification by X-ray diffraction, and microstructural analysis by SEM equipped with EDS capability. A series of AlxNiy and AlxFe y type intermetallics were observed to form by phase transformation at temperatures from 540°C to 1120°C. The sequence of the formation of intermetallics by these phase transformations closely replicated the

  7. 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

  8. Efficient usage of Adabas replication

    CERN Document Server

    Storr, Dieter W

    2011-01-01

    In today's IT organization replication becomes more and more an essential technology. This makes Software AG's Event Replicator for Adabas an important part of your data processing. Setting the right parameters and establishing the best network communication, as well as selecting efficient target components, is essential for successfully implementing replication. This book provides comprehensive information and unique best-practice experience in the field of Event Replicator for Adabas. It also includes sample codes and configurations making your start very easy. It describes all components ne

  9. Solving the Telomere Replication Problem

    Science.gov (United States)

    Maestroni, Laetitia; Matmati, Samah; Coulon, Stéphane

    2017-01-01

    Telomeres are complex nucleoprotein structures that protect the extremities of linear chromosomes. Telomere replication is a major challenge because many obstacles to the progression of the replication fork are concentrated at the ends of the chromosomes. This is known as the telomere replication problem. In this article, different and new aspects of telomere replication, that can threaten the integrity of telomeres, will be reviewed. In particular, we will focus on the functions of shelterin and the replisome for the preservation of telomere integrity. PMID:28146113

  10. Assaying environmental nickel toxicity using model nematodes.

    Science.gov (United States)

    Rudel, David; Douglas, Chandler D; Huffnagle, Ian M; 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.

  11. Assaying environmental nickel toxicity using model nematodes.

    Directory of Open Access Journals (Sweden)

    David Rudel

    Full Text Available 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.

  12. 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. elegansand 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.

  13. 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......, it is well known by dermatologists specialized in occupational skin diseases, and by their nickel-allergic patients, that hand eczema in cashiers and other professionals who handle coins may be caused or aggravated by nickel release from coins. In this review, we present evidence from past studies showing...... that nickel-containing coins can indeed pose a risk for those who handle them. For protection of the health of consumers, cashiers, and other workers who handle coins, it is suggested that coins without nickel release should be used as a substitute for the high nickel-releasing coins currently in widespread...

  14. 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...... group. Nickel-sensitive women had significantly higher levels of nickel in toe-nails, hair and plasma than had control subjects, whereas there was no significant difference in nickel concentration in finger-nails between the two groups. No correlation could be demonstrated between nickel levels in any...... combination of nails, hair and plasma in the nickel-hypersensitive or in the control group....

  15. Restructuring of porous nickel electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Lenhart, S.J.; Macdonald, D.D.; Pound, B.G.

    1984-08-01

    A transmission line model for the electrochemical impedance of porous electrodes was used to study the degradation of nickel battery plates throughout their cycle life. The model was shown to successfully account for changes in the observed electrode properties in terms of simultaneous restructuring of the active mass and rupture of particleparticle ohmic contacts.

  16. Polymer-templated mesoporous carbons synthesized in the presence of nickel nanoparticles, nickel oxide nanoparticles, and nickel nitrate

    Science.gov (United States)

    Choma, Jerzy; Jedynak, Katarzyna; Marszewski, Michal; Jaroniec, Mietek

    2012-02-01

    Mesoporous carbon composites, containing nickel and nickel oxide nanoparticles, were obtained by soft-templating method. Samples were synthesized under acidic conditions using resorcinol and formaldehyde as carbon precursors, poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock co-polymer Lutrol F127 as a soft template and nickel and nickel oxide nanoparticles, and nickel nitrate as metal precursors. In addition, a one set of samples was obtained by impregnation of mesoporous carbons with a nickel nitrate solution followed by further annealing at 400 °C. Wide angle X-ray powder diffraction along with thermogravimetric analysis proved the presence of nickel nanoparticles in the final composites obtained using nickel and nickel oxide nanoparticles, and Ni(NO3)2 solution. Whereas, the impregnation of carbons with a nickel nitrate solution followed by annealing at 400 °C resulted in needle-like nickel oxide nanoparticles present inside the composites’ pores. Low-temperature (-196 °C) nitrogen physisorption, X-ray powder diffraction, and thermogravimetric analysis confirmed good adsorption and structural properties of the synthesized nickel-carbon composites, in particular, the samples possessed high surface areas (>600 m2/g), large total pore volumes (>0.50 cm3/g), and maxima of pore size distribution functions at circa 7 nm. It was found that the composites were partially graphitized during carbonization process at 850 °C. The samples are stable in an air environment below temperature of 500 °C. All these features make the synthesized nickel-carbon composites attractive materials for adsorption, catalysis, energy storage, and environmental applications.

  17. Surface wear of TiN coated nickel tool during the injection moulding of polymer micro Fresnel lenses

    DEFF Research Database (Denmark)

    Tosello, Guido; Hansen, Hans Nørgaard; Gasparin, Stefania

    2012-01-01

    Limited tool life of nickel mould inserts represents an issue for the mass-production of polymer optics with complex micro three-dimensional geometries by injection moulding. TiN coating was applied to a nickel insert for the injection moulding of polycarbonate micro Fresnel lenses. Surface wear ...... cycles the measured height reduction of 23μm high ribs was on the order of 400–1000nm....

  18. Charter School Replication. Policy Guide

    Science.gov (United States)

    Rhim, Lauren Morando

    2009-01-01

    "Replication" is the practice of a single charter school board or management organization opening several more schools that are each based on the same school model. The most rapid strategy to increase the number of new high-quality charter schools available to children is to encourage the replication of existing quality schools. This policy guide…

  19. LHCb experience with LFC replication

    CERN Document Server

    Bonifazi, F; Perez, E D; D'Apice, A; dell'Agnello, L; Düllmann, D; Girone, M; Re, G L; Martelli, B; Peco, G; Ricci, P P; Sapunenko, V; Vagnoni, V; Vitlacil, D

    2008-01-01

    Database replication is a key topic in the framework of the LHC Computing Grid to allow processing of data in a distributed environment. In particular, the LHCb computing model relies on the LHC File Catalog, i.e. a database which stores information about files spread across the GRID, their logical names and the physical locations of all the replicas. The LHCb computing model requires the LFC to be replicated at Tier-1s. The LCG 3D project deals with the database replication issue and provides a replication service based on Oracle Streams technology. This paper describes the deployment of the LHC File Catalog replication to the INFN National Center for Telematics and Informatics (CNAF) and to other LHCb Tier-1 sites. We performed stress tests designed to evaluate any delay in the propagation of the streams and the scalability of the system. The tests show the robustness of the replica implementation with performance going much beyond the LHCb requirements.

  20. DATABASE REPLICATION IN HETEROGENOUS PLATFORM

    Directory of Open Access Journals (Sweden)

    Hendro Nindito

    2014-01-01

    Full Text Available The application of diverse database technologies in enterprises today is increasingly a common practice. To provide high availability and survavibality of real-time information, a database replication technology that has capability to replicate databases under heterogenous platforms is required. The purpose of this research is to find the technology with such capability. In this research, the data source is stored in MSSQL database server running on Windows. The data will be replicated to MySQL running on Linux as the destination. The method applied in this research is prototyping in which the processes of development and testing can be done interactively and repeatedly. The key result of this research is that the replication technology applied, which is called Oracle GoldenGate, can successfully manage to do its task in replicating data in real-time and heterogeneous platforms.

  1. LHCb experience with LFC replication

    CERN Document Server

    Carbone, Angelo; Dafonte Perez, Eva; D'Apice, Antimo; dell'Agnello, Luca; Duellmann, Dirk; Girone, Maria; Lo Re, Giuseppe; Martelli, Barbara; Peco, Gianluca; Ricci, Pier Paolo; Sapunenko, Vladimir; Vagnoni, Vincenzo; Vitlacil, Dejan

    2007-01-01

    Database replication is a key topic in the framework of the LHC Computing Grid to allow processing of data in a distributed environment. In particular, the LHCb computing model relies on the LHC File Catalog, i.e. database which stores information about files spread across the GRID, their logical names and the physical locations of all the replicas. The LHCb computing model requires the LFC to be replicated at Tier-1s. The LCG 3D project deals with the database replication issue and provides a replication service based on Oracle Streams technology. This paper describes the deployment of the LHC File Catalog replication to the INFN National Center for Telematics and Informations (CNAF) and to other LHCb Tier-1 sites. We performed stress tests designed to evaluate any delay in the propagation of the streams and the scalability of the system. The tests show the robustness of the replica implementation with performance going much beyond the LHCb requirements.

  2. Electrochromic Performance of Nanocomposite Nickel Oxide Counter Electrodes Containing Lithium and Zirconium

    Energy Technology Data Exchange (ETDEWEB)

    Engtrakul, Chaiwat [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Lin, Feng [Formerly NREL; Colorado School of Mines; Montano, Manuel [Colorado School of Mines; Tian, Chixia [Colorado School of Mines; Ji, Yazhou [Colorado School of Mines; Nordlund, Dennis [SLAC National Accelerator Laboratory; Weng, Tsu-Chien [SLAC National Accelerator Laboratory; Moore, Rob G. [SLAC National Accelerator Laboratory; Gillaspie, Dane T. [Formerly NREL; Jones, Kim M. [Formerly NREL; Dillon, Anne C. [Formerly NREL; Richards, Ryan M. [Colorado School of Mines

    2013-12-02

    Nickel oxide materials are suitable for counter electrodes in complementary electrochromic devices. The state-of-the-art nickel oxide counter electrode materials are typically prepared with multiple additives to enhance peformance. Herein, nanocomposite nickel oxide counter electrodes were fabricated via RF magnetron co-sputtering from Ni-Zr alloy and Li2O ceramic targets. The as-deposited nanocomposite counter electrodes were characterized with inductively coupled plasma mass spectrometry (ICP-MS), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and X-ray absorption spectroscopy (XAS). It was found that the stoichiometry, crystal structure and electronic structure of the nickel oxide-based materials could be readily tuned by varying the Li2O sputter deposition power level. Comprehensive electrochromic evaluation demonstrated that the performance of the nickel oxide-based materials was dependent on the overall Li stoichiometry. Overall, the nanocomposite nickel oxide counter electrode containing lithium and zirconium synthesized with a Li2O deposition power of 45 W exhibited the optimal performance with an optical modulation of 71% and coloration efficiency of 30 cm2/C at 670 nm in Li-ion electrolyte.

  3. Nickel inhibits mitochondrial fatty acid oxidation.

    Science.gov (United States)

    Uppala, Radha; McKinney, Richard W; Brant, Kelly A; Fabisiak, James P; Goetzman, Eric S

    2015-08-07

    Nickel exposure is associated with changes in cellular energy metabolism which may contribute to its carcinogenic properties. Here, we demonstrate that nickel strongly represses mitochondrial fatty acid oxidation-the pathway by which fatty acids are catabolized for energy-in both primary human lung fibroblasts and mouse embryonic fibroblasts. At the concentrations used, nickel suppresses fatty acid oxidation without globally suppressing mitochondrial function as evidenced by increased glucose oxidation to CO2. Pre-treatment with l-carnitine, previously shown to prevent nickel-induced mitochondrial dysfunction in neuroblastoma cells, did not prevent the inhibition of fatty acid oxidation. The effect of nickel on fatty acid oxidation occurred only with prolonged exposure (>5 h), suggesting that direct inhibition of the active sites of metabolic enzymes is not the mechanism of action. Nickel is a known hypoxia-mimetic that activates hypoxia inducible factor-1α (HIF1α). Nickel-induced inhibition of fatty acid oxidation was blunted in HIF1α knockout fibroblasts, implicating HIF1α as one contributor to the mechanism. Additionally, nickel down-regulated the protein levels of the key fatty acid oxidation enzyme very long-chain acyl-CoA dehydrogenase (VLCAD) in a dose-dependent fashion. In conclusion, inhibition of fatty acid oxidation by nickel, concurrent with increased glucose metabolism, represents a form of metabolic reprogramming that may contribute to nickel-induced carcinogenesis.

  4. 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.

  5. Stereospecific nickel-catalyzed cross-coupling reactions of alkyl ethers: enantioselective synthesis of diarylethanes.

    Science.gov (United States)

    Taylor, Buck L H; Swift, Elizabeth C; Waetzig, Joshua D; Jarvo, Elizabeth R

    2011-01-26

    Secondary benzylic ethers undergo stereospecific substitution reactions with Grignard reagents in the presence of nickel catalysts. Reactions proceed with inversion of configuration and high stereochemical fidelity. This reaction allows for facile enantioselective synthesis of biologically active diarylethanes from readily available optically enriched carbinols.

  6. Laminated electrochromic windows based on nickel oxide, tungsten oxide, and gel electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Passerini, S.; Scrosati, B.; Hermann, V. (Univ. di Roma (Italy). Dipt. di Chimica); Holmblad, C.; Bartlett, T. (Medtronic Promeon, Minneapolis, MN (United States))

    1994-04-01

    The characteristic and the performance of solid-state, laminated electrochromic windows using tungsten oxide as the principal electrochromic electrode and nonstoichiometric nickel oxide as the counterelectrode separated by selected gel electrolytes, are presented and discussed. These advanced-design, electro-optical devices show a very promising behavior in terms of light modulation and cyclability.

  7. NACSA Charter School Replication Guide: The Spectrum of Replication Options. Authorizing Matters. Replication Brief 1

    Science.gov (United States)

    O'Neill, Paul

    2010-01-01

    One of the most important and high-profile issues in public education reform today is the replication of successful public charter school programs. With more than 5,000 failing public schools in the United States, there is a tremendous need for strong alternatives for parents and students. Replicating successful charter school models is an…

  8. 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...... nickel in drinking water (12 micrograms Ni/kg) and, at different time intervals, standardized 1400-kJ portions of scrambled eggs. When nickel was ingested in water 30 min or 1 h prior to the meal, peak nickel concentrations in serum occurred 1 h after the water intake, and the peak was 13-fold higher...... than the one seen 1 h after simultaneous intake of nickel-containing water and scrambled eggs. In the latter case, a smaller, delayed peak occurred 3 h after the meal. Median urinary nickel excretion half-times varied between 19.9 and 26.7 h. Within 3 days, the amount of nickel excreted corresponded...

  9. Repeated patch testing to nickel during childhood do not induce nickel sensitization

    DEFF Research Database (Denmark)

    Søgaard Christiansen, Elisabeth

    2014-01-01

    Background: Previously, patch test reactivity to nickel sulphate in a cohort of unselected infants tested repeatedly at 3-72 months of age has been reported. A reproducible positive reaction at 12 and 18 months was selected as a sign of nickel sensitivity, provided a patch test with an empty Finn...... chamber was negative. The objective of this study is to follow-up on infants with suspected nickel sensitivity. Methods: A total of 562 infants were included in the cohort and patch tested with nickel sulphate. The 26 children with a positive patch test to nickel sulphate at 12 and 18 months were offered...... repeated patch test to nickel sulphate at 3 (36 months), 6 (72 months) and 14 years of age. Results: At 3 years, 24 of 26 nickel sensitive children were retested and a positive reaction was seen in 7 children, a negative reaction in 16 and 1 child was excluded due to reaction to both nickel and the empty...

  10. Terahertz-Driven Nonlinear Spin Response of Antiferromagnetic Nickel Oxide

    Science.gov (United States)

    Baierl, S.; Mentink, J. H.; Hohenleutner, M.; Braun, L.; Do, T.-M.; Lange, C.; Sell, A.; Fiebig, M.; Woltersdorf, G.; Kampfrath, T.; Huber, R.

    2016-11-01

    Terahertz magnetic fields with amplitudes of up to 0.4 Tesla drive magnon resonances in nickel oxide while the induced dynamics is recorded by femtosecond magneto-optical probing. We observe distinct spin-mediated optical nonlinearities, including oscillations at the second harmonic of the 1 THz magnon mode. The latter originate from coherent dynamics of the longitudinal component of the antiferromagnetic order parameter, which are probed by magneto-optical effects of second order in the spin deflection. These observations allow us to dynamically disentangle electronic from lattice-related contributions to magnetic linear birefringence and dichroism—information so far only accessible by ultrafast THz spin control. The nonlinearities discussed here foreshadow physics that will become essential in future subcycle spin switching.

  11. 40 CFR 415.470 - Applicability; description of the nickel salts production subcategory.

    Science.gov (United States)

    2010-07-01

    ... nickel salts production subcategory. 415.470 Section 415.470 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Nickel Salts Production Subcategory § 415.470 Applicability; description of the nickel... nickel salts, including (a) nickel sulfate, nickel chloride, nickel nitrate, and nickel fluoborate,...

  12. 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.

  13. International Expansion through Flexible Replication

    DEFF Research Database (Denmark)

    Jonsson, Anna; Foss, Nicolai Juul

    2011-01-01

    to local environments and under the impact of new learning. To illuminate these issues, we draw on a longitudinal in-depth study of Swedish home furnishing giant IKEA, involving more than 70 interviews. We find that IKEA has developed organizational mechanisms that support an ongoing learning process aimed......, etc.) are replicated in a uniform manner across stores, and change only very slowly (if at all) in response to learning (“flexible replication”). We conclude by discussing the factors that influence the approach to replication adopted by an international replicator....

  14. Growth and Chlorophyll Content of Canola Plants Supplied with Urea and Ammonium Nitrate in Response to Various Nickel Levels

    OpenAIRE

    BYBORDI, Ahmad; Mohammad Nabi GHEIBI

    2009-01-01

    Both the beneficial and the adverse effects of various nickel level supplements on growth and chlorophyll content of canola plants were evaluated while either urea or ammonium nitrate was supplied as the sole N source in the nutrient solutions. This study was arranged in completely randomized with three replications. Treatments included nutrient solution cultures containing urea and ammonium nitrate at the rate of 84 mg N L-1 separately as nitrogen sources with four nickel levels as NiSO4.6H2...

  15. 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...

  16. The Psychology of Replication and Replication in Psychology.

    Science.gov (United States)

    Francis, Gregory

    2012-11-01

    Like other scientists, psychologists believe experimental replication to be the final arbiter for determining the validity of an empirical finding. Reports in psychology journals often attempt to prove the validity of a hypothesis or theory with multiple experiments that replicate a finding. Unfortunately, these efforts are sometimes misguided because in a field like experimental psychology, ever more successful replication does not necessarily ensure the validity of an empirical finding. When psychological experiments are analyzed with statistics, the rules of probability dictate that random samples should sometimes be selected that do not reject the null hypothesis, even if an effect is real. As a result, it is possible for a set of experiments to have too many successful replications. When there are too many successful replications for a given set of experiments, a skeptical scientist should be suspicious that null or negative findings have been suppressed, the experiments were run improperly, or the experiments were analyzed improperly. This article describes the implications of this observation and demonstrates how to test for too much successful replication by using a set of experiments from a recent research paper.

  17. Regulation of Replication Recovery and Genome Integrity

    DEFF Research Database (Denmark)

    Colding, Camilla Skettrup

    Preserving genome integrity is essential for cell survival. To this end, mechanisms that supervise DNA replication and respond to replication perturbations have evolved. One such mechanism is the replication checkpoint, which responds to DNA replication stress and acts to ensure replication pausing...

  18. Recent advances in homogeneous nickel catalysis.

    Science.gov (United States)

    Tasker, Sarah Z; Standley, Eric A; Jamison, Timothy F

    2014-05-15

    Tremendous advances have been made in nickel catalysis over the past decade. Several key properties of nickel, such as facile oxidative addition and ready access to multiple oxidation states, have allowed the development of a broad range of innovative reactions. In recent years, these properties have been increasingly understood and used to perform transformations long considered exceptionally challenging. Here we discuss some of the most recent and significant developments in homogeneous nickel catalysis, with an emphasis on both synthetic outcome and mechanism.

  19. Simultaneous determination of arsenic, cadmium, calcium, chromium, cobalt, copper, iron, lead, magnesium, manganese, molybdenum, nickel, selenium, and zinc in fertilizers by microwave acid digestion and inductively coupled plasma-optical emission spectrometry detection: single-laboratory validation of a modification and extension of AOAC 2006.03.

    Science.gov (United States)

    Webb, Sharon; Bartos, James; Boles, Rhonda; Hasty, Elaine; Thuotte, Ethel; Thiex, Nancy J

    2014-01-01

    A single-laboratory validation study was conducted for the simultaneous determination of arsenic, cadmium, calcium, cobalt, copper, chromium, iron, lead, magnesium, manganese, molybdenum, nickel, selenium, and zinc in all major types of commercial fertilizer products by microwave digestion and inductively coupled plasma-optical emission spectroscopy analysis. This validation study proposes an extension and modification of AOAC 2006.03. The extension is the inclusion of calcium, copper, iron, magnesium, manganese, and zinc, and the modification is incorporation of hydrochloric acid in the digestion system. This dual acid digestion utilizes both hydrochloric and nitric acids in a 3 to 9 mL volume ratio/100 mL. In addition to 15 of the 30 original validation materials used in the 2006.03 collaborative study, National Institute of Standards and Technology Standard Reference Material 695 and Magruder 2009-06 were incorporated as accuracy materials. The main benefits of this proposed method are a significant increase in laboratory efficiency when compared to the use of both AOAC Methods 965.09 and 2006.03 to achieve the same objective and an enhanced recovery of several metals.

  20. Thermomagnetic analysis of hydrogenated nickel

    Science.gov (United States)

    Tavares, S. S. M.; Miraglia, S.; Lafuente, A.; Fruchart, D.

    2002-04-01

    The effect of hydrogen inserted by electrolytic charging on the magnetic properties of nickel is discussed by taking into account the thermomagnetic analysis (TMA), X-ray diffraction and saturation magnetization results. After hydrogenation, thin foils of nickel presented a biphasic structure of metastable β-NiH x ( x=0.67±0.07) and α-Ni (with <0.03 at% H). During room temperature aging the β-NiH x hydride decomposes into α-Ni and H 2. The TMA heating curves obtained just after hydrogenation show two magnetic transitions, the first one in the range 100-120°C and the second that of Curie point of Ni. Between the first and the second transition an abrupt increase of magnetization is observed, which is due to the formation of more ferromagnetic nickel from the hydride decomposition. On the other hand, the first transition of the TMA curve can only be attributed to the ferromagnetism of some regions of phase β.

  1. Low patch test reactivity to nickel in unselected adolescents tested repeatedly with nickel in infancy

    DEFF Research Database (Denmark)

    Christiansen, Elisabeth Soegaard; Andersen, Klaus Ejner; Bindslev-Jensen, Carsten

    2016-01-01

    BACKGROUND: It is questionable how repeated patch tests with nickel sulphate in infancy affect nickel patch test reactivity at a later age. METHODS: The DARC cohort encompasses 562 infants invited to a clinical examination including patch tests with nickel sulphate 6 times during the first 36 mon...

  2. Assessment of functional integrity of liver among workers exposed to soluble nickel compounds during nickel plating

    Directory of Open Access Journals (Sweden)

    Kalahasthi Ravi Babu

    2006-01-01

    Full Text Available The present study investigates the functional integrity of liver among workers exposed to nickel during nickel-plating process. The functional integrity of liver was assessed in 69 workers who are exposed to nickel during nickel plating and considered as nickel-exposed workers; and 50 administrative workers residing in same city, but away from the place of work of study group, were considered as control group. The level of urine nickel was measured by using a flameless atomic absorption spectrophotometer. Using kits supplied by Bayer Diagnostics, we determined serum markers of liver function tests. Results: The levels of urine nickel were significantly increased in high-and moderate-exposure groups as compared to control group. The levels of serum transaminases -viz, alanine transaminase and aspartate transaminase-were significantly increased in nickel-exposed workers, who had high urine nickel levels as compared to control group. The level of serum albumin was negatively correlated with urine nickel levels. The levels of serum transaminases and serum g- glutamyl- transpeptidase were positively and significantly correlated with urine nickel levels. Conclusion: Results indicate that workers who had high urine nickel levels had a consistent effect on hepatic inflammatory function.

  3. Electro-Chemically Enhanced Mechanical Polishing of Nickel Mandrels

    Science.gov (United States)

    Gubarev, Mikhail; Ramsey, Brian; Engelhaupt, Darell

    2006-01-01

    Grinding and mechanical polishing techniques used for x-ray optics mandrel figuring lead to mid-frequency surface ripple. These small figure variations have to be addressed in order to improve the performance of the resulting x-ray mirrors. If the electrochemical etching is combined with mechanical polishing, the figuring and the surface finishing cm be done simultaneously and be used to correct the mid-frequency surface ripple. It is shown that the electrochemical mechanical polishing method allows selective removal of nickel alloy without mandrel surface microroughness degradation.

  4. Simple Thermal Decompose Method for Synthesis of Nickel Disulfide Nanostructures

    Science.gov (United States)

    Seyghalkar, Hamideh; Sabet, Mohammad; Salavati-Niasari, Masoud

    2016-11-01

    In this work, a simple thermal decompose method was served to synthesize NiS2 nanostructures via a nickel complex. Also polyethylene glycol (PEG) was used as surfactant to increase the steric effect around nanostructure surfaces and decrease the particles size. The product was characterized with different analysis methods. The crystal structure of the product was studied by X-ray diffraction (XRD) pattern. The particle size and morphology were investigated by scanning electron microscopy (SEM). To study the nanostructures surface purity, Fourier transform infrared spectroscopy (FT-IR) was used. And finally to study the optical properties of the product photoluminescence (PL) spectroscopy was served.

  5. Deep-groove nickel gratings for solar thermal absorbers

    Science.gov (United States)

    Ahmad, N.; Núñez-Sánchez, S.; Pugh, J. R.; Cryan, M. J.

    2016-10-01

    This paper presents measured and modelled optical absorptance and reflectance for deep-groove nickel nano-gratings in the 450-950 nm wavelength range. The structures have been fabricated using focused ion beam etching and characterised using Fourier spectroscopy and the field distributions on the gratings have been studied using finite difference time domain modelling. Realistic grating structures have been modelled based on focused ion beam cross sections and these results are in good agreement between measured and modelled results. The roles of surface plasmon polaritons and slot modes are highlighted in the strong broadband absorbance that can be achieved with these structures.

  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...... was 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. 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.

  8. Mineral resource of the month: nickel

    Science.gov (United States)

    Kuck, Peter H.

    2006-01-01

    Together with chromium, nickel makes steel more resistant to corrosion. Stainless steel thus accounts for more than 65 percent of primary nickel consumption in the world. One of the more common grades of stainless steel is Type 304, which contains 18 to 20 percent chromium and 10.5 to 12 percent nickel. Owing to their high corrosion resistance, nickel-bearing stainless steels are widely used in the transportation sector, the energy sector, the food preparation and processing industry, the beverage industry, the pharmaceutical industry and the medical community.

  9. Sintering of nickel steam reforming catalysts

    DEFF Research Database (Denmark)

    Sehested, Jens; Larsen, Niels Wessel; Falsig, Hanne;

    2014-01-01

    . In this paper, particle migration and coalescence in nickel steam reforming catalysts is studied. Density functional theory calculations indicate that Ni-OH dominate nickel transport at nickel surfaces in the presence of steam and hydrogen as Ni-OH has the lowest combined energies of formation and diffusion...... compared to other potential nickel transport species. The relation between experimental catalyst sintering data and the effective mass diffusion constant for Ni-OH is established by numerical modelling of the particle migration and coalescence process. Using this relation, the effective mass diffusion...

  10. On the reflectivity of nickel neutron mirrors

    Energy Technology Data Exchange (ETDEWEB)

    Adib, M.; Maayouf, R.M.A.; Abdel-Kawy, A.; Habib, N. (Atomic Energy Establishment, Cairo (Egypt). Reactor and Neutron Physics Dept.); Kenawy, M.A.; Wahba, M.; Ashry, A.H. (Ain Shams Univ., Cairo (Egypt))

    1991-02-01

    Neutron reflectivities were determined for 300 nm thick films of natural nickel and nickel 58 coated on glass plates. The measurements were performed at glancing angles between 40' and 60'. The incident neutron beam from one of the ET-RR-1 reactor horizontal channels covered neutron wavelengths between 0.55 and 0.80 nm. It was found that nickel 58, because of the high value of its critical glancing angle, is more efficient as a neutron mirror than natural nickel. (orig.).

  11. Biomarkers of replicative senescence revisited

    DEFF Research Database (Denmark)

    Nehlin, Jan

    2016-01-01

    Biomarkers of replicative senescence can be defined as those ultrastructural and physiological variations as well as molecules whose changes in expression, activity or function correlate with aging, as a result of the gradual exhaustion of replicative potential and a state of permanent cell cycle...... with their chronological age and present health status, help define their current rate of aging and contribute to establish personalized therapy plans to reduce, counteract or even avoid the appearance of aging biomarkers....

  12. Nucleotide Metabolism and DNA Replication.

    Science.gov (United States)

    Warner, Digby F; Evans, Joanna C; Mizrahi, Valerie

    2014-10-01

    The development and application of a highly versatile suite of tools for mycobacterial genetics, coupled with widespread use of "omics" approaches to elucidate the structure, function, and regulation of mycobacterial proteins, has led to spectacular advances in our understanding of the metabolism and physiology of mycobacteria. In this article, we provide an update on nucleotide metabolism and DNA replication in mycobacteria, highlighting key findings from the past 10 to 15 years. In the first section, we focus on nucleotide metabolism, ranging from the biosynthesis, salvage, and interconversion of purine and pyrimidine ribonucleotides to the formation of deoxyribonucleotides. The second part of the article is devoted to DNA replication, with a focus on replication initiation and elongation, as well as DNA unwinding. We provide an overview of replication fidelity and mutation rates in mycobacteria and summarize evidence suggesting that DNA replication occurs during states of low metabolic activity, and conclude by suggesting directions for future research to address key outstanding questions. Although this article focuses primarily on observations from Mycobacterium tuberculosis, it is interspersed, where appropriate, with insights from, and comparisons with, other mycobacterial species as well as better characterized bacterial models such as Escherichia coli. Finally, a common theme underlying almost all studies of mycobacterial metabolism is the potential to identify and validate functions or pathways that can be exploited for tuberculosis drug discovery. In this context, we have specifically highlighted those processes in mycobacterial DNA replication that might satisfy this critical requirement.

  13. Plasmid Rolling-Circle Replication.

    Science.gov (United States)

    Ruiz-Masó, J A; MachóN, C; Bordanaba-Ruiseco, L; Espinosa, M; Coll, M; Del Solar, G

    2015-02-01

    Plasmids are DNA entities that undergo controlled replication independent of the chromosomal DNA, a crucial step that guarantees the prevalence of the plasmid in its host. DNA replication has to cope with the incapacity of the DNA polymerases to start de novo DNA synthesis, and different replication mechanisms offer diverse solutions to this problem. Rolling-circle replication (RCR) is a mechanism adopted by certain plasmids, among other genetic elements, that represents one of the simplest initiation strategies, that is, the nicking by a replication initiator protein on one parental strand to generate the primer for leading-strand initiation and a single priming site for lagging-strand synthesis. All RCR plasmid genomes consist of a number of basic elements: leading strand initiation and control, lagging strand origin, phenotypic determinants, and mobilization, generally in that order of frequency. RCR has been mainly characterized in Gram-positive bacterial plasmids, although it has also been described in Gram-negative bacterial or archaeal plasmids. Here we aim to provide an overview of the RCR plasmids' lifestyle, with emphasis on their characteristic traits, promiscuity, stability, utility as vectors, etc. While RCR is one of the best-characterized plasmid replication mechanisms, there are still many questions left unanswered, which will be pointed out along the way in this review.

  14. Metrology for the Development of High Energy X-Ray Optics

    Science.gov (United States)

    Gubarev, Mikhail; Ramsey, Brian; Engelhaupt, Darell; Dpeegle, Chet

    2005-01-01

    We are developing grazing incidence x-ray optics for a balloon-borne hard-x-ray telescope (HERO). The instrument will have 200 sq cm effective collecting area at 40 keV and an angular resolution goal of 15 arcsec. The HERO mirror shells are fabricated using electroform-nickel replication off super-polished cylindrical mandrels. The angular resolution goal puts stringent requirements on the quality of x-ray mirrors and, hence, on mandrel quality. We used metrology in an iterative approach to monitor and refine the x- ray mirror fabrication process. Comparison of surface figure and microroughness measurements of the mandrel and the shells will be presented together with results from x-ray tests.

  15. Growth and Chlorophyll Content of Canola Plants Supplied with Urea and Ammonium Nitrate in Response to Various Nickel Levels

    Directory of Open Access Journals (Sweden)

    Ahmad BYBORDI

    2009-12-01

    Full Text Available Both the beneficial and the adverse effects of various nickel level supplements on growth and chlorophyll content of canola plants were evaluated while either urea or ammonium nitrate was supplied as the sole N source in the nutrient solutions. This study was arranged in completely randomized with three replications. Treatments included nutrient solution cultures containing urea and ammonium nitrate at the rate of 84 mg N L-1 separately as nitrogen sources with four nickel levels as NiSO4.6H2O at the rates of 0, 0.01, 0.05 and 0.1 mg Ni L-1. Plants were allowed to grow for 6 weeks then leaves chlorophyll content and shoots and roots fresh and dry weight were determined. Both plant growth and leaves chlorophyll content of the urea-fed plants increased significantly with the increase in nickel content up to 0.1 mg Ni L-1. However, root fresh and dry weight increased up to 0.01 mg Ni L-1 and started to decrease with further increase in solutions nickel content. Nickel did not affect these parameters with plants supplied with ammonium nitrate significantly. In these plants, the optimum nickel level for shoot growth and leaves chlorophyll content was 0.05 mg L-1 and for root fresh and dry weight was 0.01 mg Ni L-1. Further increase in Ni concentration reduced growth. As a whole, plants received urea plus nickel performed better than those received ammonium nitrate plus nickel.

  16. 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

    2014-08-01

    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.

  17. 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...

  18. Nickel: Impact on leaf morphology and growth

    Science.gov (United States)

    The nutritional physiology of essential micronutrients in pecan, especially that of nickel, is a limiting factor in optimization of physiological efficiency of orchard enterprises. Knowledge by farmers and extension specialists about the role of nickel, a newly recognized micronutrient, is meager. ...

  19. Crystallographic orientations and twinning of electrodeposited nickel

    DEFF Research Database (Denmark)

    Alimadadi, Hossein; da Silva Fanta, Alice Bastos; Somers, Marcel A. J.;

    2014-01-01

    A series of nickel layers was electrodeposited at different current densities from a Watts type electrolyte containing the additive 2-butyne-1,4-diol in various concentrations. The internal structure of the nickel electrodeposits was systematically investigated applying complementary microscopic...

  20. 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.

  1. Chemical Bath Deposition of Nickel Sulphide (Ni4S3 Thin Films

    Directory of Open Access Journals (Sweden)

    Darren TEO

    2010-12-01

    Full Text Available Thin films of nickel sulphide were deposited from aqueous baths on indium tin oxide glass substrate. The chemical bath contained nickel sulphate, sodium thiosulfate and triethanolamine solutions. The aim of the present study was to analyze the different experimental conditions to prepare Ni4S3 thin films using chemical bath deposition technique. The structural, morphological and optical properties of nickel sulphide thin films were obtained by X-ray diffraction, atomic force microscopy and UV-Vis Spectrophotometer will be presented. The properties of the films varied with the variation in the deposition parameters. The films deposited at longer deposition time using lower concentration in more acidic medium showed improved crystallinity, good uniformity and better adhesion to the substrate. Films showed band gap of 0.35 eV and exhibited p-type semiconductor behaviour.

  2. Selective Ablation of thin Nickel-chromium-alloy Films Using Ultrashort Pulsed Laser

    Science.gov (United States)

    Pabst, Linda; Ebert, Robby; Exner, Horst

    The selective ablation of 100nm thin Nickel-Chromium-alloy films on glass substrate was investigated using femtosecond laser pulses (λ=1030nm, τp=170 fs, Ep,max=7μJ). The influence of the processing parameters such as fluence, pulse number and pulse repetition rate on the ablation process was examined. Single and multiple pulses ablation thresholds of the Nickel-Chromium-alloy film were determined and the incubation coefficient calculated. Optical and electron microscopy were employed to characterize the patterned area. As a result, different irradiation morphologies were observed, dependent from the processing parameters. A processing window for film side ablation of the Nickel-Chromium-alloy film without damaging the underlying glass substrate was found, however, the edge of the ablation craters were covered with laser induced periodic surface structures (LIPSS).

  3. Novel material for nickel recuperation

    Directory of Open Access Journals (Sweden)

    José A. da Rocha Filho

    2001-01-01

    Full Text Available Graft polymerization of N-vinyl-2-pyrrolidone with chitin was studied using hydrogen peroxide for initiation. The capacity of the obtained VP-g-Ch graft copolymer for adsorption of nickel was examined. The effect of temperature, pH and solute concentration on the chelating properties of the grafted and ungrafted chitin were determined. The thermal profiles obtained showed higher thermal resistance for the VP-g-Ch than chitin. The results indicate that the obtained graft copolymer under investigation is a potentially powerful ion exchanger that can be employed for heavy metals removal from wastewater effluents.

  4. Structure investigations of electrodeposited nickel

    Energy Technology Data Exchange (ETDEWEB)

    Vertes, A.; Czako-Nagy, I.; Lakatos-Varsani, M. (Eoetvoes Lorand Tudomanyegyetem, Budapest (Hungary). Dept. of Physical Chemistry); Kajcsos, Z. (Hungarian Academy of Sciences, Budapest. Central Research Inst. for Physics); Csordas, L. (Eoetvoes Lorand Tudomanyegyetem, Budapest (Hungary). Dept. of Solid State Physics); Brauer, G. (Zentralinstitut fuer Kernforschung, Rossendorf bei Dresden (German Democratic Republic)); Leidheiser, H. Jr. (Lehigh Univ., Bethlehem, PA (USA). Center for Surface and Coatings Research)

    1982-08-01

    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.

  5. 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

  6. 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...... micrograms/l to 77 micrograms/l. Examination of the aluminium and nickel contents of the constituents for the production of one brand showed too low levels to explain the final contamination of the product. By following the aluminium and nickel concentrations of the same brand during the production...... of a batch of albumin solution, filtration was shown to contribute to contamination, although the largest increase in aluminium as well as nickel concentrations appeared during the bulk concentrating process. To avoid health risks to certain patients, regulations should be established requiring aluminium...

  7. APT characterization of high nickel RPV steels

    Science.gov (United States)

    Miller, M. K.; Sokolov, M. A.; Nanstad, R. K.; Russell, K. F.

    2006-06-01

    The microstructures of three high nickel content pressure vessel steels have been characterized by atom probe tomography to investigate the influence of high nickel levels on the response to neutron irradiation of high and low copper pressure vessel steels. The high-nickel, low-manganese, low-copper VVER-1000 weld and forging exhibited lower than predicted levels of embrittlement during neutron irradiation. The Palisades weld exhibits a Δ T41 J of 102 °C which was significantly lower than the value of 154 °C predicted by Reg. Guide 1.99 Rev. 2. Atom probe tomography revealed nickel-, manganese-, and silicon-enriched precipitates in both the VVER-1000 base and weld materials after neutron irradiation. A high number density of copper-, nickel-, manganese-, silicon- and phosphorus-enriched precipitates were observed in the Palisades weld after neutron irradiation. Atom probe tomography also revealed high levels of phosphorus segregation to the dislocations in all three materials.

  8. Nanoparticles of nickel oxide: growth and organization on zinc-substituted anionic clay matrix by one-pot route at room temperature

    Science.gov (United States)

    Carja, Gabriela; Nakajima, Akira; Dranca, Cristian; Okada, Kiyoshi

    2010-10-01

    A room temperature nanocarving strategy is developed for the fabrication of nanoparticles of nickel oxide on zinc-substituted anionic clay matrix (Ni/ZnLDH). It is based on the growth and organization of nanoparticles of nickel oxide which occur during the structural reconstruction of the layered structure of the anionic clay in NiSO4 aqueous solution. No organic compounds are used during the fabrication. The described material was characterized by X-ray diffraction (XRD), IR spectroscopy (FTIR), transmission electron microscopy (TEM), field-emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) spectroscopy, and X-ray photoelectron spectroscopy (XPS). Results show that the nickel-clay nanoarchitecture consists of small nanoparticles of nickel oxide (average size 7 nm) deposited on the larger nanoparticles (average size 90 nm) of zinc-substituted clay. The optical properties of the new nickel-zinc formulation are studied by UV-Vis.

  9. Defects of mitochondrial DNA replication.

    Science.gov (United States)

    Copeland, William C

    2014-09-01

    Mitochondrial DNA is replicated by DNA polymerase γ in concert with accessory proteins such as the mitochondrial DNA helicase, single-stranded DNA binding protein, topoisomerase, and initiating factors. Defects in mitochondrial DNA replication or nucleotide metabolism can cause mitochondrial genetic diseases due to mitochondrial DNA deletions, point mutations, or depletion, which ultimately cause loss of oxidative phosphorylation. These genetic diseases include mitochondrial DNA depletion syndromes such as Alpers or early infantile hepatocerebral syndromes, and mitochondrial DNA deletion disorders, such as progressive external ophthalmoplegia, ataxia-neuropathy, or mitochondrial neurogastrointestinal encephalomyopathy. This review focuses on our current knowledge of genetic defects of mitochondrial DNA replication (POLG, POLG2, C10orf2, and MGME1) that cause instability of mitochondrial DNA and mitochondrial disease.

  10. Regulation of beta cell replication

    DEFF Research Database (Denmark)

    Lee, Ying C; Nielsen, Jens Høiriis

    2008-01-01

    Beta cell mass, at any given time, is governed by cell differentiation, neogenesis, increased or decreased cell size (cell hypertrophy or atrophy), cell death (apoptosis), and beta cell proliferation. Nutrients, hormones and growth factors coupled with their signalling intermediates have been...... suggested to play a role in beta cell mass regulation. In addition, genetic mouse model studies have indicated that cyclins and cyclin-dependent kinases that determine cell cycle progression are involved in beta cell replication, and more recently, menin in association with cyclin-dependent kinase...... inhibitors has been demonstrated to be important in beta cell growth. In this review, we consider and highlight some aspects of cell cycle regulation in relation to beta cell replication. The role of cell cycle regulation in beta cell replication is mostly from studies in rodent models, but whether...

  11. Personality and Academic Motivation: Replication, Extension, and Replication

    Science.gov (United States)

    Jones, Martin H.; McMichael, Stephanie N.

    2015-01-01

    Previous work examines the relationships between personality traits and intrinsic/extrinsic motivation. We replicate and extend previous work to examine how personality may relate to achievement goals, efficacious beliefs, and mindset about intelligence. Approximately 200 undergraduates responded to the survey with a 150 participants replicating…

  12. 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.

  13. Systemic contact dermatitis after oral exposure to nickel

    DEFF Research Database (Denmark)

    Jensen, Christian Stab; Menné, Torkil; Johansen, Jeanne Duus

    2006-01-01

    Systemic contact dermatitis can be elicited experimentally in nickel-sensitive individuals by oral nickel exposure. A crucial point interpreting such experiments has been the relevance of nickel exposure from drinking water and diet. The aim of this meta-analysis study on former nickel-exposure i...

  14. Regulation of Replication Recovery and Genome Integrity

    DEFF Research Database (Denmark)

    Colding, Camilla Skettrup

    facilitate replication recovery after MMS-induced replication stress. Our data reveal that control of Mrc1 turnover through the interplay between posttranslational modifications and INQ localization adds another layer of regulation to the replication checkpoint. We also add replication recovery to the list...... is mediated by Mrc1, which ensures Mec1 presence at the stalled replication fork thus facilitating Rad53 phosphorylation. When replication can be resumed safely, the replication checkpoint is deactivated and replication forks restart. One mechanism for checkpoint deactivation is the ubiquitin......-targeted proteasomal degradation of Mrc1. In this study, we describe a novel nuclear structure, the intranuclear quality control compartment (INQ), which regulates protein turnover and is important for recovery after replication stress. We find that upon methyl methanesulfonate (MMS)-induced replication stress, INQ...

  15. Hyperthermia stimulates HIV-1 replication.

    Directory of Open Access Journals (Sweden)

    Ferdinand Roesch

    Full Text Available HIV-infected individuals may experience fever episodes. Fever is an elevation of the body temperature accompanied by inflammation. It is usually beneficial for the host through enhancement of immunological defenses. In cultures, transient non-physiological heat shock (42-45°C and Heat Shock Proteins (HSPs modulate HIV-1 replication, through poorly defined mechanisms. The effect of physiological hyperthermia (38-40°C on HIV-1 infection has not been extensively investigated. Here, we show that culturing primary CD4+ T lymphocytes and cell lines at a fever-like temperature (39.5°C increased the efficiency of HIV-1 replication by 2 to 7 fold. Hyperthermia did not facilitate viral entry nor reverse transcription, but increased Tat transactivation of the LTR viral promoter. Hyperthermia also boosted HIV-1 reactivation in a model of latently-infected cells. By imaging HIV-1 transcription, we further show that Hsp90 co-localized with actively transcribing provirus, and this phenomenon was enhanced at 39.5°C. The Hsp90 inhibitor 17-AAG abrogated the increase of HIV-1 replication in hyperthermic cells. Altogether, our results indicate that fever may directly stimulate HIV-1 replication, in a process involving Hsp90 and facilitation of Tat-mediated LTR activity.

  16. Hyperthermia stimulates HIV-1 replication.

    Science.gov (United States)

    Roesch, Ferdinand; Meziane, Oussama; Kula, Anna; Nisole, Sébastien; Porrot, Françoise; Anderson, Ian; Mammano, Fabrizio; Fassati, Ariberto; Marcello, Alessandro; Benkirane, Monsef; Schwartz, Olivier

    2012-01-01

    HIV-infected individuals may experience fever episodes. Fever is an elevation of the body temperature accompanied by inflammation. It is usually beneficial for the host through enhancement of immunological defenses. In cultures, transient non-physiological heat shock (42-45°C) and Heat Shock Proteins (HSPs) modulate HIV-1 replication, through poorly defined mechanisms. The effect of physiological hyperthermia (38-40°C) on HIV-1 infection has not been extensively investigated. Here, we show that culturing primary CD4+ T lymphocytes and cell lines at a fever-like temperature (39.5°C) increased the efficiency of HIV-1 replication by 2 to 7 fold. Hyperthermia did not facilitate viral entry nor reverse transcription, but increased Tat transactivation of the LTR viral promoter. Hyperthermia also boosted HIV-1 reactivation in a model of latently-infected cells. By imaging HIV-1 transcription, we further show that Hsp90 co-localized with actively transcribing provirus, and this phenomenon was enhanced at 39.5°C. The Hsp90 inhibitor 17-AAG abrogated the increase of HIV-1 replication in hyperthermic cells. Altogether, our results indicate that fever may directly stimulate HIV-1 replication, in a process involving Hsp90 and facilitation of Tat-mediated LTR activity.

  17. Cellular Responses to Replication Problems

    NARCIS (Netherlands)

    M. Budzowska (Magdalena)

    2008-01-01

    textabstractDuring every S-phase cells need to duplicate their genomes so that both daughter cells inherit complete copies of genetic information. It is a tremendous task, given the large sizes of mammalian genomes and the required precision of DNA replication. A major threat to the accuracy and eff

  18. Covert Reinforcement: A Partial Replication.

    Science.gov (United States)

    Ripstra, Constance C.; And Others

    A partial replication of an investigation of the effect of covert reinforcement on a perceptual estimation task is described. The study was extended to include an extinction phase. There were five treatment groups: covert reinforcement, neutral scene reinforcement, noncontingent covert reinforcement, and two control groups. Each subject estimated…

  19. Crinivirus replication and host interactions

    Directory of Open Access Journals (Sweden)

    Zsofia A Kiss

    2013-05-01

    Full Text Available Criniviruses comprise one of the genera within the family Closteroviridae. Members in this family are restricted to the phloem and rely on whitefly vectors of the genera Bemisia and/or Trialeurodes for plant-to-plant transmission. All criniviruses have bipartite, positive-sense ssRNA genomes, although there is an unconfirmed report of one having a tripartite genome. Lettuce infectious yellows virus (LIYV is the type species of the genus, the best studied so far of the criniviruses and the first for which a reverse genetics system was available. LIYV RNA 1 encodes for proteins predicted to be involved in replication, and alone is competent for replication in protoplasts. Replication results in accumulation of cytoplasmic vesiculated membranous structures which are characteristic of most studied members of the Closteroviridae. These membranous structures, often referred to as BYV-type vesicles, are likely sites of RNA replication. LIYV RNA 2 is replicated in trans when co-infecting cells with RNA 1, but is temporally delayed relative to RNA1. Efficient RNA 2 replication also is dependent on the RNA 1-encoded RNA binding protein, P34. No LIYV RNA 2-encoded proteins have been shown to affect RNA replication, but at least four, CP, CPm, Hsp70h, and p59 are virion structural components and CPm is a determinant of whitefly transmissibility. Roles of other LIYV RNA 2-encoded proteins are largely as yet unknown, but P26 is a non-virion protein that accumulates in cells as characteristic plasmalemma deposits which in plants are localized within phloem parenchyma and companion cells over plasmodesmata connections to sieve elements. The two remaining crinivirus-conserved RNA 2-encoded proteins are P5 and P9. P5 is 39 amino acid protein and is encoded at the 5’ end of RNA 2 as ORF1 and is part of the hallmark closterovirus gene array. The orthologous gene in BYV has been shown to play a role in cell-to-cell movement and indicated to be localized to the

  20. FOXSI: Properties of optics and detectors for hard-X rays

    Science.gov (United States)

    Camilo Buitrago-Casas, Juan; Glesener, Lindsay; Christe, Steven; Krucker, Sam; Ishikawa, Shin-nosuke; Foster, Natalie

    2015-04-01

    The Focusing Optics X-ray Solar Imager (FOXSI) is a state-of-the-art direct focusing X-ray telescope designed to observe the Sun. This experiment completed its second flight onboard a sounding rocket last December 11, 2014 from the White Sands Missile Range in New Mexico. The optics use a set of iridium-coated nickel/cobalt mirrors made using a replication technique based on an electroformed perfect polished surface. Since this technique creates full shells that no need to be co-aligned with other segments, an angular resolution of up to ~5 arcsec is gotten. The FOXSI focal plane consists of seven double-sided strip detectors. Five Silicon and 2 CdTe detectors were used during the second flight.We present on various properties of Wolter-I optics that are applicable to solar HXR observation, including ray-tracing simulations of the single-bounce (“ghost ray”) patterns from sources outside the field of view and angular resolution for different source angles and effective area measurements of the FOXSI optics. We also present the detectors calibration results, paying attention to energy resolution (~0.5 keV), energy thresholds (~4-15 keV for Silicon and ~4-20 keV for CdTe detectors), and spatial coherence of these values over the entire detector.

  1. Transient Influx of Nickel in Root Mitochondria Modulates Organic Acid and Reactive Oxygen Species Production in Nickel Hyperaccumulator Alyssum murale*

    Science.gov (United States)

    Agrawal, Bhavana; Czymmek, Kirk J.; Sparks, Donald L.; Bais, Harsh P.

    2013-01-01

    Mitochondria are important targets of metal toxicity and are also vital for maintaining metal homeostasis. Here, we examined the potential role of mitochondria in homeostasis of nickel in the roots of nickel hyperaccumulator plant Alyssum murale. We evaluated the biochemical basis of nickel tolerance by comparing the role of mitochondria in closely related nickel hyperaccumulator A. murale and non-accumulator Alyssum montanum. Evidence is presented for the rapid and transient influx of nickel in root mitochondria of nickel hyperaccumulator A. murale. In an early response to nickel treatment, substantial nickel influx was observed in mitochondria prior to sequestration in vacuoles in the roots of hyperaccumulator A. murale compared with non-accumulator A. montanum. In addition, the mitochondrial Krebs cycle was modulated to increase synthesis of malic acid and citric acid involvement in nickel hyperaccumulation. Furthermore, malic acid, which is reported to form a complex with nickel in hyperaccumulators, was also found to reduce the reactive oxygen species generation induced by nickel. We propose that the interaction of nickel with mitochondria is imperative in the early steps of nickel uptake in nickel hyperaccumulator plants. Initial uptake of nickel in roots results in biochemical responses in the root mitochondria indicating its vital role in homeostasis of nickel ions in hyperaccumulation. PMID:23322782

  2. Nickel on the Swedish market: follow-up 10 years after entry into force of the EU Nickel Directive.

    NARCIS (Netherlands)

    Biesterbos, J.W.H.; Yazar, K.; Liden, C.

    2010-01-01

    BACKGROUND: The EU Nickel Directive, aimed at primary and secondary prevention of nickel allergy by limitation of nickel release from certain items, came fully into force in July 2001. OBJECTIVES: To assess the prevalence on the market of items with nickel release and to compare the outcome with pre

  3. Transient Influx of nickel in root mitochondria modulates organic acid and reactive oxygen species production in nickel hyperaccumulator Alyssum murale.

    Science.gov (United States)

    Agrawal, Bhavana; Czymmek, Kirk J; Sparks, Donald L; Bais, Harsh P

    2013-03-08

    Mitochondria are important targets of metal toxicity and are also vital for maintaining metal homeostasis. Here, we examined the potential role of mitochondria in homeostasis of nickel in the roots of nickel hyperaccumulator plant Alyssum murale. We evaluated the biochemical basis of nickel tolerance by comparing the role of mitochondria in closely related nickel hyperaccumulator A. murale and non-accumulator Alyssum montanum. Evidence is presented for the rapid and transient influx of nickel in root mitochondria of nickel hyperaccumulator A. murale. In an early response to nickel treatment, substantial nickel influx was observed in mitochondria prior to sequestration in vacuoles in the roots of hyperaccumulator A. murale compared with non-accumulator A. montanum. In addition, the mitochondrial Krebs cycle was modulated to increase synthesis of malic acid and citric acid involvement in nickel hyperaccumulation. Furthermore, malic acid, which is reported to form a complex with nickel in hyperaccumulators, was also found to reduce the reactive oxygen species generation induced by nickel. We propose that the interaction of nickel with mitochondria is imperative in the early steps of nickel uptake in nickel hyperaccumulator plants. Initial uptake of nickel in roots results in biochemical responses in the root mitochondria indicating its vital role in homeostasis of nickel ions in hyperaccumulation.

  4. Structural characterization of nickel oxide/hydroxide nanosheets produced by CBD technique

    Energy Technology Data Exchange (ETDEWEB)

    Taşköprü, T., E-mail: ttaskopru@anadolu.edu.tr [Department of Physics, Anadolu University, Eskişehir 26470 (Turkey); Department of Physics, Çankırı Karatekin University, Çankırı 18100 (Turkey); Zor, M.; Turan, E. [Department of Physics, Anadolu University, Eskişehir 26470 (Turkey)

    2015-10-15

    Graphical abstract: SEM images of (a) as deposited β-Ni(OH)2 and (b) NiO samples deposited with pH 10 solution. The inset figures shows the absorbance spectra of (a) β-Ni(OH)2 and (b) NiO samples. - Highlights: • The formation of β-Ni(OH){sub 2} and NiO were confirmed with XRD, SEM, FT-IR and Raman. • Porous nickel oxide was synthesized after heat treatment of nickel hydroxide. • The increase in pH value changes the nanoflake structure to hexagonal nanosheet. • On increasing the pH from 8 to 11, the band gap decreases from 3.52 to 3.37 eV. - Abstract: Nickel hydroxide samples were deposited onto glass substrates using Ni(NO{sub 3}){sub 2}·6H{sub 2}O and aqueous ammonia by chemical bath deposition technique. The influence of pH of solution was investigated by means of X-ray diffraction, field emission scanning electron microscopy, Fourier transform infrared, Raman spectroscopy, optical absorption and BET analysis. The as-deposited samples were identified as β-Ni(OH){sub 2}, were transformed into NiO after heat treatment in air at 500 °C for 2 h. Porous nickel oxide nanosheets are obtained by heating nickel hydroxide nanosheets. The optical transitions observed in the absorbance spectra below optical band gap is due to defects or Ni{sup 2+} vacancies in NiO samples. The band gap energy of NiO samples changes between 3.37 and 3.52 eV depending on the pH values.

  5. Study of Novel EUV Absorber : Nickel and Nickel Oxide

    Energy Technology Data Exchange (ETDEWEB)

    Woo, Dong Gon; Kim, Jung Hwan; Kim, Jung Sik; Hong, Seongchul; Ahn, Jinho [Hanyang University, Seoul (Korea, Republic of)

    2017-03-15

    The shadowing effect is one of the most urgent issues yet to be solved in high-volume manufacturing using extreme ultraviolet lithography (EUVL). Many studies have been conducted to mitigate the unexpected results caused by shadowing effects. The simplest way to mitigate the shadowing effect is to reduce the thickness of the absorber. Since nickel has high extinction coefficients in the EUV wavelengths, it is one of more promising absorber material candidates. A Ni based absorber exhibited imaging performance comparable to a Tantalum nitride absorber. However, the Ni-based absorber showed a dramatic reduction in horizontal-vertical critical dimension (H-V CD) bias. Therefore, limitations in fabricating a EUV mask can be mitigated by using the Ni based absorber.

  6. Development of a Micro-Fiber Nickel Electrode for Nickel-Hydrogen Cell

    Science.gov (United States)

    Britton, Doris L.

    1996-01-01

    The development of a high specific energy battery is one of the objectives of the lightweight nickel-hydrogen (NiH2) program at the NASA Lewis Research Center. The approach has been to improve the nickel electrode by continuing combined in-house and contract efforts to develop a more efficient and lighter weight electrode for the nickel-hydrogen fuel cell. Small fiber diameter nickel plaques are used as conductive supports for the nickel hydroxide active material. These plaques are commercial products and have an advantage of increased surface area available for the deposition of active materials. Initial tests include activation and capacity measurements at different discharge levels followed by half-cell cycle testing at 80 percent depth-of-discharge in a low Earth orbit regime. The electrodes that pass the initial tests are life cycle tested in a boiler plate nickel-hydrogen cell before flightweight designs are built and tested.

  7. 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.

  8. Synthesis and Characterization of Electrodeposited Nanocrystalline Nickel

    Institute of Scientific and Technical Information of China (English)

    DAI Pin-qiang; YU Hui, LI Qiang

    2004-01-01

    Nanocrystalline nickel was synthesize d by direct current electrodeposition from a modified Watts-type bath. X-ray diffraction and transmission electron microscope were used to characterize the microstructure of nickel deposits. The results show that nanocrytalline nickel with grain sizes in the range 20~50nm can be synthesized from saccharin-containing Watts-type baths with current density range 5~30A/dm2. There existed preferred orientation in the deposits and it changed progressively from a (200) fibre texture to a (111) (200) double fibre texture as saccharin concentration increased. The hardness of the deposits increased prominently as grain size decreased to nanometer range.

  9. 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.

  10. Nickel coated graphite fiber conductive composites

    Energy Technology Data Exchange (ETDEWEB)

    Evans, R.E.; Hall, D.E.; Luxon, B.A.

    1986-07-01

    Nickel coated graphite (NCG) fiber, consisting of a thin continuous plating of high purity nickel over an aerospace-grade graphite core, offers performance added features by combining the lightweight and high structural reinforcement of graphite fiber with the thermal and electrical conductivity of nickel. These NCG filaments, which are composite constructions in their own right, can be processed and impregnated with thermosetting or thermoplastic resins in the same manner that graphite fiber tows are processed and impregnated to produce roving, tape or fabric prepreg. Therefore, NCG fibers can be readily integrated into structural laminate assemblies using established composites-manufacturing practices.

  11. Synthesis and Characterization of Electrodeposited Nanocrystalline Nickel

    Institute of Scientific and Technical Information of China (English)

    DAIPin-qiang; YUHui; LIQiang

    2004-01-01

    Nanocrystalline nickel was synthesized by direct current electrodeposition from a modified Watts-type bath. X-ray diffraction and transmission electron microscope were used to characterize the microstructure of nickel deposits. The results show that nanocrytalline nickel with grain sizes in the range 20-50nm can be synthesized from saccharin-containing Watts-type baths with current density range 5-30A/dm2. There existed preferred orientation in the deposits and it changed progressively from a (200) fibre texture to a (111) (200) double fibre texture as saccharin concentration increased. The hardness of the deposits increased prominently as grain size decreased to nanometer range.

  12. Clinical bending of nickel titanium wires

    Directory of Open Access Journals (Sweden)

    Stephen Chain

    2015-01-01

    Full Text Available Since the evolution and the involvement of Nickel Titanium wires in the field of Orthodontics. The treatment plan has evolved with the use of low force Nickel Titanium wires. Because of their high springback, low stiffness, they are the key initial wires in leveling and alignment but have poor formability. Since poor formability limits its ability to create variable arch forms thus; limits the form of treatment. We have devised a method to bend the Nickel Titanium wires to help in our inventory but also customized the wire according to the treatment.

  13. Indonesia Prohibited Export of Laterite Nickel Ore, China’s Nickel Industry Responded Calmly

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    <正>On January 12,the Indonesia government implemented new mining regulation to prohibit export of laterite nickel ore and other crude ores.This may cause certain impact on China’s nickel industry which is in a rapid development period.What countermeasures to adopt has become the hot spot and focal point of the nickel industry and iron & steel industry including stainless steel industry.Recently,when receiving interview from reporters of the

  14. Replication-Uncoupled Histone Deposition during Adenovirus DNA Replication

    OpenAIRE

    Komatsu, Tetsuro; Nagata, Kyosuke

    2012-01-01

    In infected cells, the chromatin structure of the adenovirus genome DNA plays critical roles in its genome functions. Previously, we reported that in early phases of infection, incoming viral DNA is associated with both viral core protein VII and cellular histones. Here we show that in late phases of infection, newly synthesized viral DNA is also associated with histones. We also found that the knockdown of CAF-1, a histone chaperone that functions in the replication-coupled deposition of his...

  15. REPLICATION TOOL AND METHOD OF PROVIDING A REPLICATION TOOL

    DEFF Research Database (Denmark)

    2016-01-01

    structured master surface (3a, 3b, 3c, 3d) having a lateral master pattern and a vertical master profile. The microscale structured master surface (3a, 3b, 3c, 3d) has been provided by localized pulsed laser treatment to generate microscale phase explosions. A method for producing a part with microscale......The invention relates to a replication tool (1, 1a, 1b) for producing a part (4) with a microscale textured replica surface (5a, 5b, 5c, 5d). The replication tool (1, 1a, 1b) comprises a tool surface (2a, 2b) defining a general shape of the item. The tool surface (2a, 2b) comprises a microscale...... energy directors on flange portions thereof uses the replication tool (1, 1a, 1b) to form an item (4) with a general shape as defined by the tool surface (2a, 2b). The formed item (4) comprises a microscale textured replica surface (5a, 5b, 5c, 5d) with a lateral arrangement of polydisperse microscale...

  16. Growth of Carbon Encapsulated Long Nickel Nanorods on Bulk Nickel Substrate

    Institute of Scientific and Technical Information of China (English)

    BIN Xiaobei; CHEN Jiazang; XUE Jun; WANG Xuehua; TU Wenmao; CAO Hong

    2011-01-01

    Carbon nanotube encapsulated nickel nanorods were catalytic grown via pyrolysis of oil on a bulk nickel wire substrate. X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy and Raman spectroscopy were employed to characterize the as-prepared sample. The results show that, carbon nanotubes possess several microns in length, the filled metallic nickel nanorods with a uniform diameter of 35 nm were tightly encapsulated by the carbon capsules. The detailed formation mechanism for the carbon nanotubes encapsulated nickel nanorods were discussed briefly.

  17. The Nuts and Bolts of Zinc-Nickel: OEM Zinc Nickel Implementation on Fasteners - Getting It Into Production

    Science.gov (United States)

    2014-11-01

    Blake Simpson Louie Tran The Nuts and Bolts of Zinc- Nickel OEM Zinc Nickel Implementation on Fasteners – Getting It Into Production Report...REPORT TYPE 3. DATES COVERED 00-00-2014 to 00-00-2014 4. TITLE AND SUBTITLE The Nuts and Bolts of Zinc- Nickel : OEM Zinc Nickel Implementation on...currently in production 2. Problem at Hand – Hexavalent Chromates 3. Transition to Zinc- Nickel 4. Preliminary Testing 5. Plan moving forward for

  18. Wetlife Study of Nickel Hydrogen Cells

    Science.gov (United States)

    2007-01-01

    A study was undertaken to determine the residual Nickel Precharge, and to understand the Performance and Cycle Life of Aged Nickel Hydrogen cells that were in cold storage up to thirteen (13) years. Comsat Technical Services, Aerospace Corporation, and NSWC/Crane test data to date indicate a nominal electrical performance with a small second plateau and the presence of Nickel Precharge in the cells: Cell Teardown, Plate (active Nickel Precharge determination), and Electrolyte Analyses are in progress. Preliminary Thermal Imaging data indicates that older the cell greater the heat generation, but cell over charge (capacity) could dominate heat generation. U.S. Govt. cells has completed 1150 nominal 60% LEO cycles. The completion date for this study is January 31, 2008.

  19. 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.

  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. Standard Specification for Low-Carbon Nickel-Chromium-Molybdenum, Low-Carbon Nickel-Chromium-Molybdenum-Copper, Low-Carbon Nickel-Chromium-Molybdenum-Tantalum, Low-Carbon Nickel-Chromium-Molybdenum-Tungsten, and Low-Carbon Nickel-Molybdenum-Chromium Alloy Plate, Sheet, and Strip

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2015-01-01

    Standard Specification for Low-Carbon Nickel-Chromium-Molybdenum, Low-Carbon Nickel-Chromium-Molybdenum-Copper, Low-Carbon Nickel-Chromium-Molybdenum-Tantalum, Low-Carbon Nickel-Chromium-Molybdenum-Tungsten, and Low-Carbon Nickel-Molybdenum-Chromium Alloy Plate, Sheet, and Strip

  2. Standard Specification for Low-Carbon Nickel-Chromium-Molybdenum, Low-Carbon Nickel-Molybdenum-Chromium, Low-Carbon Nickel-Molybdenum-Chromium-Tantalum, Low-Carbon Nickel-Chromium-Molybdenum-Copper, and Low-Carbon Nickel-Chromium-Molybdenum-Tungsten Alloy Rod

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2015-01-01

    Standard Specification for Low-Carbon Nickel-Chromium-Molybdenum, Low-Carbon Nickel-Molybdenum-Chromium, Low-Carbon Nickel-Molybdenum-Chromium-Tantalum, Low-Carbon Nickel-Chromium-Molybdenum-Copper, and Low-Carbon Nickel-Chromium-Molybdenum-Tungsten Alloy Rod

  3. Replicator dynamics in value chains

    DEFF Research Database (Denmark)

    Cantner, Uwe; Savin, Ivan; Vannuccini, Simone

    2016-01-01

    The pure model of replicator dynamics though providing important insights in the evolution of markets has not found much of empirical support. This paper extends the model to the case of firms vertically integrated in value chains. We show that i) by taking value chains into account, the replicator...... dynamics may revert its effect. In these regressive developments of market selection, firms with low fitness expand because of being integrated with highly fit partners, and the other way around; ii) allowing partner's switching within a value chain illustrates that periods of instability in the early...... stage of industry life-cycle may be the result of an 'optimization' of partners within a value chain providing a novel and simple explanation to the evidence discussed by Mazzucato (1998); iii) there are distinct differences in the contribution to market selection between the layers of a value chain...

  4. Therapeutic targeting of replicative immortality

    OpenAIRE

    Yaswen, Paul; MacKenzie, Karen L.; Keith, W. Nicol; Hentosh, Patricia; Rodier, Francis; Zhu, Jiyue; Firestone, Gary L.; Matheu, Ander; Carnero, Amancio; Bilsland, Alan; Sundin, Tabetha; Honoki, Kanya; Fujii, Hiromasa; Georgakilas, Alexandros G.; Amedei, Amedeo

    2015-01-01

    One of the hallmarks of malignant cell populations is the ability to undergo continuous proliferation. This property allows clonal lineages to acquire sequential aberrations that can fuel increasingly autonomous growth, invasiveness, and therapeutic resistance. Innate cellular mechanisms have evolved to regulate replicative potential as a hedge against malignant progression. When activated in the absence of normal terminal differentiation cues, these mechanisms can result in a state of persis...

  5. Alphavirus polymerase and RNA replication.

    Science.gov (United States)

    Pietilä, Maija K; Hellström, Kirsi; Ahola, Tero

    2017-01-16

    Alphaviruses are typically arthropod-borne, and many are important pathogens such as chikungunya virus. Alphaviruses encode four nonstructural proteins (nsP1-4), initially produced as a polyprotein P1234. nsP4 is the core RNA-dependent RNA polymerase but all four nsPs are required for RNA synthesis. The early replication complex (RC) formed by the polyprotein P123 and nsP4 synthesizes minus RNA strands, and the late RC composed of fully processed nsP1-nsP4 is responsible for the production of genomic and subgenomic plus strands. Different parts of nsP4 recognize the promoters for minus and plus strands but the binding also requires the other nsPs. The alphavirus polymerase has been purified and is capable of de novo RNA synthesis only in the presence of the other nsPs. The purified nsP4 also has terminal adenylyltransferase activity, which may generate the poly(A) tail at the 3' end of the genome. Membrane association of the nsPs is vital for replication, and alphaviruses induce membrane invaginations called spherules, which form a microenvironment for RNA synthesis by concentrating replication components and protecting double-stranded RNA intermediates. The RCs isolated as crude membrane preparations are active in RNA synthesis in vitro, but high-resolution structure of the RC has not been achieved, and thus the arrangement of viral and possible host components remains unknown. For some alphaviruses, Ras-GTPase-activating protein (Src-homology 3 (SH3) domain)-binding proteins (G3BPs) and amphiphysins have been shown to be essential for RNA replication and are present in the RCs. Host factors offer an additional target for antivirals, as only few alphavirus polymerase inhibitors have been described.

  6. Nickel hydroxide precipitation from aqueous sulfate media

    Science.gov (United States)

    Sist, Cinziana; Demopoulos, George P.

    2003-08-01

    Hydrometallurgical processing of laterite ores constitutes a major industrial and R&D activity in extractive metallurgy. In some of the process flowsheets, nickel hydroxide precipitation is incorporated. For these operations, the optimization of nickel hydroxide precipitation is important to assure efficiency and product quality. The main objective of this investigation was to study and improve the precipitation characteristics of Ni(OH)2 in a sulfate system using supersaturation controlled precipitation.

  7. Some Aspects of Sealed Nickel Cadmium Cells

    Directory of Open Access Journals (Sweden)

    P. K. Saha

    1967-11-01

    Full Text Available Sealed Nickel Cadmium Cell system is termed till today as the most reliable power pack for electronic apparatus specially in low temperature use. This paper brings out the development and production of sealed nickel cadmium cells of pocket plate construction. The author who has gained experience in production of Ni-Cd cells in East Germany discusses also the major problems faced by the battery manufactures of to-day.

  8. Nickel hydrogen cell development for space applications

    Energy Technology Data Exchange (ETDEWEB)

    Harvey, J.M. (Marconi Elliott Avionic Systems Ltd., Borehamwood (UK))

    1990-01-01

    A number of types of Nickel Hydrogen cells for space applications - geostationary or low earth orbit satellites - have been designed within the UK. Testing under various charge/discharge conditions and at various temperatures has been done for a 50 Ah GEO cell, and is currently under way for a LEO cell. The paper describes the design developments and performance achievements of the Nickel Hydrogen cells.

  9. Nickel metal hydride LEO cycle testing

    Science.gov (United States)

    Lowery, Eric

    1995-01-01

    The George C. Marshall Space Flight Center is working to characterize aerospace AB5 Nickel Metal Hydride (NiMH) cells. The cells are being evaluated in terms of storage, low earth orbit (LEO) cycling, and response to parametric testing (high rate charge and discharge, charge retention, pulse current ability, etc.). Cells manufactured by Eagle Picher are the subjects of the evaluation. There is speculation that NiMH cells may become direct replacements for current Nickel Cadmium cells in the near future.

  10. Dynamic replication of Web contents

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The phenomenal growth of the World Wide Web has brought huge increase in the traffic to the popular web sites.Long delays and denial of service experienced by the end-users,especially during the peak hours,continues to be the common problem while accessing popular sites.Replicating some of the objects at multiple sites in a distributed web-server environment is one of the possible solutions to improve the response time/Iatency. The decision of what and where to replicate requires solving a constraint optimization problem,which is NP-complete in general.In this paper, we consider the problem of placing copies of objects in a distributed web server system to minimize the cost of serving read and write requests when the web servers have Iimited storage capacity.We formulate the problem as a 0-1 optimization problem and present a polynomial time greedy algorithm with backtracking to dynamically replicate objects at the appropriate sites to minimize a cost function.To reduce the solution search space,we present necessary condi tions for a site to have a replica of an object jn order to minimize the cost function We present simulation resuIts for a variety of problems to illustrate the accuracy and efficiency of the proposed algorithms and compare them with those of some well-known algorithms.The simulation resuIts demonstrate the superiority of the proposed algorithms.

  11. Nickel-induced microwheel-like surface morphological evolution of ZnO thin films by spray pyrolysis

    Science.gov (United States)

    Tarwal, N. L.; Shinde, P. S.; Oh, Y. W.; Cerc Korošec, Romana; Patil, P. S.

    2012-11-01

    Nickel-zinc oxide (Ni-ZnO) thin films were deposited onto glass and tin-doped indium oxide-coated glass substrates by using a pneumatic spray pyrolysis technique at 450 °C from aqueous solutions of zinc acetate and nickel acetate precursors. The effect of nickel doping on structural, morphological and optical properties of the ZnO thin films has been studied. The X-ray diffraction patterns confirmed the polycrystalline nature of the films having hexagonal crystal structure. Ni-ZnO films with appropriate nickel doping revealed the occurrence of novel wheel-like surface morphology. The absorption edge of the Ni-ZnO films showed a red shift, meaning that the optical band gap energy decreases as the nickel doping concentration increases. A growth model is developed and proposed for the novel wheel-like morphology. All the thin films exhibited room-temperature photoluminescence. Pure ZnO and Ni-ZnO thin films were tested for their photoelectrochemical performance in 0.5 M Na2SO4 electrolyte solution. The values of fill factor and open circuit voltage were improved for the Ni-ZnO thin films.

  12. Nickel-induced microwheel-like surface morphological evolution of ZnO thin films by spray pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Tarwal, N.L.; Shinde, P.S.; Patil, P.S. [Shivaji University, Thin Film Materials Laboratory, Department of Physics, Kolhapur, Maharashtra (India); Oh, Y.W. [Kyungnam University, Department of Nano Engineering, Masan (Korea, Republic of); Cerc Korosec, Romana [University of Ljubljana, Faculty of Chemistry and Chemical Technology, Ljubljana (Slovenia)

    2012-11-15

    Nickel-zinc oxide (Ni-ZnO) thin films were deposited onto glass and tin-doped indium oxide-coated glass substrates by using a pneumatic spray pyrolysis technique at 450 C from aqueous solutions of zinc acetate and nickel acetate precursors. The effect of nickel doping on structural, morphological and optical properties of the ZnO thin films has been studied. The X-ray diffraction patterns confirmed the polycrystalline nature of the films having hexagonal crystal structure. Ni-ZnO films with appropriate nickel doping revealed the occurrence of novel wheel-like surface morphology. The absorption edge of the Ni-ZnO films showed a red shift, meaning that the optical band gap energy decreases as the nickel doping concentration increases. A growth model is developed and proposed for the novel wheel-like morphology. All the thin films exhibited room-temperature photoluminescence. Pure ZnO and Ni-ZnO thin films were tested for their photoelectrochemical performance in 0.5 M Na{sub 2}SO{sub 4} electrolyte solution. The values of fill factor and open circuit voltage were improved for the Ni-ZnO thin films. (orig.)

  13. 复制多元光学元件的模型型芯机器集成形状检测%Machine-Integrated Form Testing of Mold Inserts for the Replication of Complex Optic Components

    Institute of Scientific and Technical Information of China (English)

    PFEIFER T; SCHMITT R; D(O)RNER D; SCHNEEFUβ K

    2004-01-01

    表面特征参数的在位检测对生产过程控制可提供十分有用的信息,从而可在制造过程中直接调节加工参数.检测要求取决于应用领域.对于超精密表面,例如微结构的或连续结构的光学器件,宜应用干涉法进行形状检测,因为干涉法有极高的精度和适应性,此外,表面可被迅速检测,因而减少生产时间.但是干涉法对机器振动、噪声或空气扰动等外界影响十分敏感,因而很难在生产环境中完成干涉测量.提出了在机械加工环境中的干涉测量和基于对在位干涉检测中各种基本干涉影响分析结果基础上的仿真.%In-situ measurements of surface characteristics can deliver very helpful informations for the process control, so that process parameters can be adjusted directly during the fabrication process. The requirements are dependent on the field of application. For the applications of ultra precise surfaces, e.g. micro structured or continuous optical components , interferometric form testing may be suited, because of its very high accuracy and flexibility. Furthermore with interferometry the surfaces can be measured very fast, which leads to a reduced production time. However, a disadvantage may be the sensitivity of interferometric systems to external influences, like machine vibrations, noise or air turbulences. Due to this reason, it is very difficult to perform interferometric measurements within a production environment. In this paper we present interferometric measurements in the manufacturing machine environment and simulation based on results of the analysis of fundamental influences on interferometers operated in-situ.

  14. Nanopatterning planar and non-planar mold surfaces for a polymer replication

    DEFF Research Database (Denmark)

    Cech, Jiri; Pranov, Henrik; Kofod, Guggi;

    2013-01-01

    , freestanding nickel foil with a reversed pattern. This foil is then used either as a direct master for polymer replication or as a master for an extremely high pressure embossing of such master onto a metallic injection mold cavity surface coated with special coating, which, when cured, forms robust and hard......, glass-like material. We have demonstrated nanopattern transfer on both planar and non-planar geometries and our nanopatterned mold coating can sustain more than 10.000 injection molding cycles. We can coat our nanopatterned mold surfaces with a monolayer of perfluorosilane to further reduce surface...

  15. 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...... investigated these effects by using a recently developed mouse model. Mice were epicutaneously sensitized with i) nickel alone, ii) nickel in the presence of cobalt, iii) cobalt alone, or iv) cobalt in the presence of nickel, and then followed by challenge with either nickel or cobalt alone. We found...... that sensitization with nickel alone induced more local inflammation than cobalt alone as measured by increased ear-swelling. Furthermore, the presence of nickel during sensitization to cobalt led to a stronger challenge response to cobalt as seen by increased ear-swelling and increased B and T cell responses...

  16. Nickel allergy and relationship with Staphylococcus aureus in atopic dermatitis

    DEFF Research Database (Denmark)

    Anna, Bogdali M.; Grazyna, Antoszczyk; Wojciech, Dyga

    2016-01-01

    Background: The increase of nickel air pollution is supposed to frequent side effects of nickel action related to virulence potential of Staphylococcus aureus in patients with nickel allergy in atopic dermatitis. The goal was to investigate the relationship between nickel allergy and infection by S....... aureus in atopic dermatitis. Methods: Nickel allergy was confirmed in atopic patients and excluded in healthy volunteers using patch testing. Infection by S. aureus was tested in atopic patients and healthy volunteers by use of API Staph system. The specific IgE for staphylococcal enterotoxin A and B...... volunteers without nickel allergy. The elevated secretion of IL-2 under nickel sulfate stimulation in vitro was exclusively found in atopic patients with nickel allergy infected by S. aureus. Conclusions: Our data suggest that nickel allergy and infection by S. aureus are linked in atopic dermatitis....

  17. 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.

  18. A Mineralogical study of nickel mattes from the kalgoorlie nickel smelter, kalgoorlie, western australia

    Science.gov (United States)

    Page, Michael L.

    1982-06-01

    The mineralogy of mattes from Western Mining Corporation Limited’s new nickel flash furnace at Kalgoorlie, Western Australia, are dominated by pentlandite, heazlewoodite and awaruite (Ni-Fe alloy). Magnetite, bornite solid-solution, chromite, and fayalite constitute the minor and trace phases. The optical and scanning electron microscopes, electron microprobe, and the X-ray diffractometer were used to examine the matte samples. Pentlandite and awaruite form subhedral to skeletal crystals and are commonly surrounded by complex intergrowths, some showing exsolution textures, of pentlandite, heazlewoodite, and sometimes bornite. In comparison to products from the old flash furnace, which had separate slag cleaning electric furnaces, these new mattes contain much larger quantities of alloy. The large alloy content results from the incorporation of the slag-cleaning electrodes and the addition of coke to the flash furnace, which produce the strong reducing conditions necessary for significant alloy growth. Matte chemistry not only controls which phases are present, but to some extent also influences the composition of these phases. Even though pentlandite-heazlewooditeawaruite-bornite is the equilibrium assemblage in the Ni-Fe-Cu-S system at temperatures below 550 °C, the variation in mineral composition suggests that disequilibrium was present during crystallization of the samples.

  19. Evaluating replicability of laboratory experiments in economics.

    Science.gov (United States)

    Camerer, Colin F; Dreber, Anna; Forsell, Eskil; Ho, Teck-Hua; Huber, Jürgen; Johannesson, Magnus; Kirchler, Michael; Almenberg, Johan; Altmejd, Adam; Chan, Taizan; Heikensten, Emma; Holzmeister, Felix; Imai, Taisuke; Isaksson, Siri; Nave, Gideon; Pfeiffer, Thomas; Razen, Michael; Wu, Hang

    2016-03-25

    The replicability of some scientific findings has recently been called into question. To contribute data about replicability in economics, we replicated 18 studies published in the American Economic Review and the Quarterly Journal of Economics between 2011 and 2014. All of these replications followed predefined analysis plans that were made publicly available beforehand, and they all have a statistical power of at least 90% to detect the original effect size at the 5% significance level. We found a significant effect in the same direction as in the original study for 11 replications (61%); on average, the replicated effect size is 66% of the original. The replicability rate varies between 67% and 78% for four additional replicability indicators, including a prediction market measure of peer beliefs.

  20. Methods to Quantify Nickel in Soils and Plant Tissues

    Directory of Open Access Journals (Sweden)

    Bruna Wurr Rodak

    2015-06-01

    Full Text Available In comparison with other micronutrients, the levels of nickel (Ni available in soils and plant tissues are very low, making quantification very difficult. The objective of this paper is to present optimized determination methods of Ni availability in soils by extractants and total content in plant tissues for routine commercial laboratory analyses. Samples of natural and agricultural soils were processed and analyzed by Mehlich-1 extraction and by DTPA. To quantify Ni in the plant tissues, samples were digested with nitric acid in a closed system in a microwave oven. The measurement was performed by inductively coupled plasma/optical emission spectrometry (ICP-OES. There was a positive and significant correlation between the levels of available Ni in the soils subjected to Mehlich-1 and DTPA extraction, while for plant tissue samples the Ni levels recovered were high and similar to the reference materials. The availability of Ni in some of the natural soil and plant tissue samples were lower than the limits of quantification. Concentrations of this micronutrient were higher in the soil samples in which Ni had been applied. Nickel concentration differed in the plant parts analyzed, with highest levels in the grains of soybean. The grain, in comparison with the shoot and leaf concentrations, were better correlated with the soil available levels for both extractants. The methods described in this article were efficient in quantifying Ni and can be used for routine laboratory analysis of soils and plant tissues.

  1. Urinary and fecal elimination of nickel in relation to air-borne nickel in a battery factory

    Energy Technology Data Exchange (ETDEWEB)

    Hassler, E.; Lind, B.; Nilsson, B.; Piscator, M.

    Nickel in urine and in air from the breathing zone of 18 male workers in a battery factory was determined weekly during 11 consecutive weeks. The study started immediately following three weeks of Christmas vacation. The nickel levels in air varied but did not increase with time. The average urinary excretion of nickel showed an increase during the first weeks, after which a steady state seemed to have been reached. There was a considerable individual variation in both exposure levels and urine nickel levels. However, a correlation between the averages of nickel in air and urine could be demonstrated on a group basis. In a second study, during one week, measurements of nickel in air and feces were made on 15 of the workers. A significant correlation was found between nickel in air and fecal nickel. Smoking habits did not seem to influence neither urinary nor fecal nickel concentrations.

  2. Urinary and fecal elimination of nickel in relation to air-borne nickel in a battery factory.

    Science.gov (United States)

    Hassler, E; Lind, B; Nilsson, B; Piscator, M

    1983-01-01

    Nickel in urine and in air from the breathing zone of 18 male workers in a battery factory was determined weekly during 11 consecutive weeks. The study started immediately following three weeks of Christmas vacation. The nickel levels in air varied but did not increase with time. The average urinary excretion of nickel showed an increase during the first weeks, after which a steady state seemed to have been reached. There was a considerable individual variation in both exposure levels and urine nickel levels. However, a correlation between the averages of nickel in air and urine could be demonstrated on a group basis. In a second study, during one week, measurements of nickel in air and feces were made on 15 of the workers. A significant correlation was found between nickel in air and fecal nickel. Smoking habits did not seem to influence neither urinary nor fecal nickel concentrations.

  3. Nickel biopathways in tropical nickel hyperaccumulating trees from Sabah (Malaysia)

    Science.gov (United States)

    van der Ent, Antony; Callahan, Damien L.; Noller, Barry N.; Mesjasz-Przybylowicz, Jolanta; Przybylowicz, Wojciech J.; Barnabas, Alban; Harris, Hugh H.

    2017-02-01

    The extraordinary level of accumulation of nickel (Ni) in hyperaccumulator plants is a consequence of specific metal sequestering and transport mechanisms, and knowledge of these processes is critical for advancing an understanding of transition element metabolic regulation in these plants. The Ni biopathways were elucidated in three plant species, Phyllanthus balgooyi, Phyllanthus securinegioides (Phyllanthaceae) and Rinorea bengalensis (Violaceae), that occur in Sabah (Malaysia) on the Island of Borneo. This study showed that Ni is mainly concentrated in the phloem in roots and stems (up to 16.9% Ni in phloem sap in Phyllanthus balgooyi) in all three species. However, the species differ in their leaves – in P. balgooyi the highest Ni concentration is in the phloem, but in P. securinegioides and R. bengalensis in the epidermis and in the spongy mesophyll (R. bengalensis). The chemical speciation of Ni2+ does not substantially differ between the species nor between the plant tissues and transport fluids, and is unambiguously associated with citrate. This study combines ion microbeam (PIXE and RBS) and metabolomics techniques (GC-MS, LC-MS) with synchrotron methods (XAS) to overcome the drawbacks of the individual techniques to quantitatively determine Ni distribution and Ni2+ chemical speciation in hyperaccumulator plants.

  4. Adenovirus sequences required for replication in vivo.

    OpenAIRE

    Wang, K.; Pearson, G D

    1985-01-01

    We have studied the in vivo replication properties of plasmids carrying deletion mutations within cloned adenovirus terminal sequences. Deletion mapping located the adenovirus DNA replication origin entirely within the first 67 bp of the adenovirus inverted terminal repeat. This region could be further subdivided into two functional domains: a minimal replication origin and an adjacent auxillary region which boosted the efficiency of replication by more than 100-fold. The minimal origin occup...

  5. 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.

  6. Moldable AR microstructures for improved laser transmission and damage resistance in CIRCM fiber optic beam delivery systems

    Science.gov (United States)

    MacLeod, Bruce D.; Hobbs, Douglas S.; Sabatino, Ernest, III

    2011-06-01

    Anti-reflecting (AR) surface relief microstructures (ARMs) are being developed as a replacement for thin-film AR coatings in laser-based systems to improve light transmission, power handling, operational bandwidth, and system reliability. Because ARMs textures have the potential to be replicated using simple embossing methods, the performance advantage and robustness of ARMs can be extended to moldable mid-infrared transmitting materials such as chalcogenide optical fibers. In this work, the optical performance of mid-infrared transparencies incorporating ARMs textures replicated from a master template has been modeled, and multiple master stamping tools have been fabricated in materials such as diamond, silicon carbide, nickel, silicon, and sapphire. Images from ARMs texture embossing trials using arsenic sulfide and arsenic selenide (AMTIR2) glasses, and fluoride glasses such as ZBLAN and indium fluoride provided by IRPhotonics, show excellent pattern transfer and fidelity. Transmission measurements of ARMs textures stamped into arsenic sulfide and arsenic selenide windows show broadband infrared performance equivalent to ARMs textured windows processed by direct patterning and etch methods. A system for molding ARMs textures directly into the end facets of multi-mode mid-infrared transmitting fibers is yielding promising initial results.

  7. Nickel allergy from adolescence to adulthood in the TOACS cohort

    DEFF Research Database (Denmark)

    Mortz, Charlotte G; Bindslev-Jensen, Carsten; Andersen, Klaus Ejner

    2013-01-01

    Background In 1995, we established a cohort of 1501 unselected eighth-grade schoolchildren to investigate the course of nickel allergy into adult life. Objectives To follow the course of nickel allergy and clinically relevant nickel dermatitis over 15 years from adolescence to adulthood, and the ......Background In 1995, we established a cohort of 1501 unselected eighth-grade schoolchildren to investigate the course of nickel allergy into adult life. Objectives To follow the course of nickel allergy and clinically relevant nickel dermatitis over 15 years from adolescence to adulthood...

  8. Bioassay of environmental nickel dusts in a particle feeding ciliate

    Energy Technology Data Exchange (ETDEWEB)

    Smith-Sonneborn, J.; Leibovitz, B.; Donathan, R.; Fisher, G.L.

    1986-01-01

    The ciliated protozoan Paramecium was used to quantitate cytotoxic and genotoxic effects of nickel particles. The biological response of these eukaryotic cells to pure nickel powder and iron-nickel powder was assayed and compared to the effect of the inorganic carcinogen nickel subsulfide. Cytotoxicity was determined by the percent survival of treated cells. Genotoxicity was indicated by significant increases in the fraction of nonviable offspring (presumed index of lethal mutations) found after self-fertilization (autogamy) in parents from the nickel-treated versus neutral control groups. The cells were exposed to the dusts and the biological effects determined. Only the nickel subsulfide consistently showed a significant increase in offspring lethality.

  9. Replication Origin Specification Gets a Push.

    Science.gov (United States)

    Plosky, Brian S

    2015-12-03

    During the gap between G1 and S phases when replication origins are licensed and fired, it is possible that DNA translocases could disrupt pre-replicative complexes (pre-RCs). In this issue of Molecular Cell, Gros et al. (2015) find that pre-RCs can be pushed along DNA and retain the ability to support replication.

  10. Exploiting replicative stress to treat cancer

    DEFF Research Database (Denmark)

    Dobbelstein, Matthias; Sørensen, Claus Storgaard

    2015-01-01

    DNA replication in cancer cells is accompanied by stalling and collapse of the replication fork and signalling in response to DNA damage and/or premature mitosis; these processes are collectively known as 'replicative stress'. Progress is being made to increase our understanding of the mechanisms...

  11. Precise tuning in platinum-nickel/nickel sulfide interface nanowires for synergistic hydrogen evolution catalysis

    Science.gov (United States)

    Wang, Pengtang; Zhang, Xu; Zhang, Jin; Wan, Sheng; Guo, Shaojun; Lu, Gang; Yao, Jianlin; Huang, Xiaoqing

    2017-01-01

    Comprising abundant interfaces, multicomponent heterostructures can integrate distinct building blocks into single entities and yield exceptional functionalities enabled by the synergistic components. Here we report an efficient approach to construct one-dimensional metal/sulfide heterostructures by directly sulfuring highly composition-segregated platinum-nickel nanowires. The heterostructures possess a high density of interfaces between platinum-nickel and nickel sulfide components, which cooperate synergistically towards alkaline hydrogen evolution reaction. The platinum-nickel/nickel sulfide heterostructures can deliver a current density of 37.2 mA cm−2 at an overpotential of 70 mV, which is 9.7 times higher than that of commercial Pt/C. The heterostructures also offer enhanced stability revealed by long-term chronopotentiometry measurements. The present work highlights a potentially powerful interface-engineering strategy for designing multicomponent heterostructures with advanced performance in hydrogen evolution reaction and beyond. PMID:28239145

  12. Computer simulations of martensitic transformations in iron-nickel and nickel-aluminium alloys

    CERN Document Server

    Meyer, R J

    1998-01-01

    This thesis focuses on the martensitic transformations in iron-nickel and nickel-aluminum alloys. Molecular-dynamics simulations have been done, employing potentials based on the so-called embedded-atom method (EAM). These potentials were obtained by a fit of parameterized functions to experimental data of the elements iron, nickel, and aluminum as well as the intermetallic compound NiAl. Many aspects of the austenitic transformation in iron-nickel alloys and both, the martensitic and austenitic transformations, in nickel-aluminum alloys were reproduced well by the simulations. The results allow to draw conclusions on the reasons of differences and similarities in the behavior of both alloy systems.

  13. Electrodeposition of nickel powder from nickel sulphate solution in presence of glycerol and sulphuric acid

    Directory of Open Access Journals (Sweden)

    S.G. Viswanath

    2013-09-01

    Full Text Available Nickel powder was obtained by electrodeposition of nickel from boric acid, glycerol and sulphuric acid. The morphology and particle size of these powders were studied. Spongy, irregular, flaky, fibrous and aggregate particles were obtained. Size of more than 85% particles was smaller than 384µm. From XRD graphs, it was found that the smaller particles are in the range of 106 and 373 nm. The apparent density of nickel powder decreased with increase in concentration of glycerol. The stability of the powder and current efficiency were also studied. In absence of nickel sulphate there was some nickel deposition on the cathode. The effect was discussed in present work. New definition for electrodeposition was suggested.

  14. Flight Weight Design Nickel-Hydrogen Cells Using Lightweight Nickel Fiber Electrodes

    Science.gov (United States)

    Britton, Doris L.; Willis, Bob; Pickett, David F.

    2003-01-01

    The goal of this program is to develop a lightweight nickel electrode for advanced aerospace nickel-hydrogen cells and batteries with improved specific energy and specific volume. The lightweight nickel electrode will improve the specific energy of a nickel-hydrogen cell by >50%. These near-term advanced batteries will reduce power system mass and volume, while decreasing the cost, thus increasing mission capabilities and enabling small spacecraft missions. This development also offers a cost savings over the traditional sinter development methods for fabrication. The technology has been transferred to Eagle-Picher, a major aerospace battery manufacturer, who has scaled up the process developed at NASA GRC and fabricated electrodes for incorporation into flight-weight nickel-hydrogen cells.

  15. Adsorption of Thiourea and Formation of Nickel-thiourea Complexes at Initial Stage of Nickel Deposition

    Institute of Scientific and Technical Information of China (English)

    HU Guang-hui; WU Hui-huang; YANG Fang-zu; LIU Xin-yu

    2004-01-01

    The effect of thiourea(TU) on the nickel deposition process was analyzed by means of linear-sweep voltammetry. Raman spectroscopy and infrared reflectance spectroscopy were used to investigate the adsorption of TU and the formation of nickel-TU complexes on copper surface. The experimental results indicate that the nucleation and the preceding conversion step are involved in the deposition of nickel on copper electrodes. TU makes the onset nucleation potential negative due to the formation of nickel-TU complexes, which can accelerate the nickel deposition. Moreover, the S atom in the TU molecule adsorbed on copper surface facilitates the coordination of TU to Ni2+. Meanwhile, TU might be adsorbed at a flatter orientation if no Ni2+ is on the surface, while at a perpendicular orientation when Ni2+ is coadsorbed.

  16. Nickel release from stainless steel and nickel titanium archwires - An in vitro study.

    Science.gov (United States)

    Hussain, Huma D; Ajith, Sreedevi D; Goel, Prachi

    2016-01-01

    This study was conducted to evaluate and compare the nickel release from stainless steel and nickel titanium archwires in artificial saliva over three months with the use of simulated fixed orthodontic appliances. Fifty simulated fixed orthodontic appliances representing half of the dental arch were used for this study. Five groups of ten samples each were made. Group A was the control group without archwires. Groups B and C contained stainless steel archwires from American Orthodontics (Sheboygan, WI, USA) and Dentaurum (Remanium, Ispringen, Germany) respectively. Groups D and E contained NiTi archwires from American Orthodontics (Sheboygan, WI, USA) and copper NiTi from Ormco (Glendora, CA) respectively. The amount of nickel released from the appliances into the artificial saliva were measured after 1 day, 7 days, 1 month, 2 months and 3 months. The mean release from each group was calculated and compared using Kruskal-Wallis test and Mann-Whitney U test. Significant release of nickel was seen in all groups up to the end of first month (p Group A (without archwire); 13.75 ppb, Group B; 15.2 ppb, Group C; 14.16 ppb, Group D; 18.6 ppb, Group E; 17.45 ppb respectively. On comparing the nickel release between all groups at each time interval, the result was not significant (p > 0.05). The highest amount of nickel was released from nickel titanium archwires, however, the quantity of nickel released from both NiTi and stainless steel archwires were not significant. The rate of nickel released was high within the first week and continued up to the first month after which the nickel content was stable in all the groups.

  17. Extraction of nickel from nickel limonite ore using dissolved gaseous SO2 - air

    Science.gov (United States)

    Wulandari, Winny; Soerawidjaja, Tatang Hernas; Joshua, Stephen; Isradi, Hashfi Rijal

    2017-01-01

    This paper reports a method of extracting nickel from nickel limonite by using dissolved SO2-air in ambient pressure. This method has been reported in the literature to be having advantages of a high selectivity of nickel towards iron, and can be conducted at ambient condition. The purpose of this study is to determine the good condition of nickel extraction from limonite ore by conducting pre-treatment and varying temperature and pH. The experiments were carried out in a five-neck reactor and comprised of three steps: pre-treatment of sample by pre-heating at 650 °C, leaching of the pre-treated sample, and analysis. The leaching solution was analyzed by using AAS (Atomic Absorption Spectrometer) method to determine the concentration of nickel and iron in the solution. The operating parameters included the acidity pH level of 3, 4, or 5 and the temperature of 30, 55, and 80 °C. The leaching was carried out up to 180 min. The mineralogical analysis of the ore was conducted by using XRD (X-Ray Diffraction) analysis. It is found that the good condition was obtained at pH 3, temperature of 80 °C, and 180 min leaching time, with nickel leaching efficiency of 21% from original nickel content. The selectivity nickel towards iron, defined by the extracted nickel (%) divided by extracted iron (%), has been found up to 2743. This method shows that nickel extraction can be carried out at very mild condition, including low temperature, atmospheric pressure and low pH.

  18. Cobalt release from inexpensive jewellery: has the use of cobalt replaced nickel following regulatory intervention?

    DEFF Research Database (Denmark)

    Thyssen, Jacob Pontoppidan; Jellesen, Morten S; Menné, Torkil

    2010-01-01

    Before the introduction of the EU Nickel Directive, concern was raised that manufacturers of jewellery might turn from the use of nickel to cobalt following the regulatory intervention on nickel exposure.......Before the introduction of the EU Nickel Directive, concern was raised that manufacturers of jewellery might turn from the use of nickel to cobalt following the regulatory intervention on nickel exposure....

  19. Titanium-Zirconium-Nickel Alloy Inside Marshall's Electrostatic Levitator (ESL)

    Science.gov (United States)

    2003-01-01

    This Photo, which appeared on the July cover of `Physics Today', is of the Electrostatic Levitator (ESL) at NASA's Marshall Space Flight Center (MSFC). The ESL uses static electricity to suspend an object (about 3-4 mm in diameter) inside a vacuum chamber allowing scientists to record a wide range of physical properties without the sample contracting the container or any instruments, conditions that would alter the readings. Once inside the chamber, a laser heats the sample until it melts. The laser is then turned off and the sample cools, changing from a liquid drop to a solid sphere. In this particular shot, the ESL contains a solid metal sample of titanium-zirconium-nickel alloy. Since 1977, the ESL has been used at MSFC to study the characteristics of new metals, ceramics, and glass compounds. Materials created as a result of these tests include new optical materials, special metallic glasses, and spacecraft components.

  20. Low frequency terahertz-induced demagnetization in ferromagnetic nickel

    Science.gov (United States)

    Shalaby, Mostafa; Vicario, Carlo; Hauri, Christoph P.

    2016-05-01

    A laser stimulus at terahertz (THz) frequency is expected to offer superior control over magnetization dynamics compared to an optical pulse, where ultrafast demagnetization is mediated by heat deposition. As a THz field cycle occurs on a timescale similar to the natural speed of spin motions, this can open a path for triggering precessional magnetization motion and ultimately ultrafast magnetic switching by the THz magnetic field component, without quenching. Here, we explore the ultrafast magnetic response of a ferromagnetic nickel thin film excited by a strong (33 MV/cm) terahertz transient in non-resonant conditions. While the magnetic laser pulse component induces ultrafast magnetic precessions, we experimentally found that at high pump fluence, the THz pulse leads to large quenching which dominates the precessional motion by far. Furthermore, degradation of magnetic properties sets in and leads to permanent modifications of the Ni thin film and damage.

  1. Electroless Nickel Plating and Electroplating on FBG Temperature Sensor

    Institute of Scientific and Technical Information of China (English)

    SHEN Ren-sheng; TENG Rui; LI Xiang-ping; ZHANG Jin; XIA Dao-cheng; FAN Zhao-qi; YU Yong-sen; ZHANG Yu-shu; DU Guo-tong

    2008-01-01

    Metal-coated fiber Bragg grating(FBG) temperature sensors were prepared via electroless nickel(EN) plating and tin electroplating methods on the surface of normal bare FBG.The surface morphologies of the metal-coated layers were observed under a metallographic microscope.The effects of pretreatment sequence,pH value of EN plating solution and current density of electroplating on the performance of the metal-coated layers were analyzed.Meanwhile,the Bragg wavelength shift induced by temperature was monitored by an optical spectrum analyzer.Sensitivity of the metal-coated FBG(MFBG) sensor was almost two times that of normal bare FBG sensor.The measuring temperature of the MFBG sensor could be up to 280 ℃,which was much better than that of conventional FBG sensor.

  2. Plasma spheroidization of nickel powders in a plasma reactor

    Indian Academy of Sciences (India)

    G Shanmugavelayutham; V Selvarajan

    2004-10-01

    Thermal spray coatings of surfaces with metal, alloy and ceramic materials for protection against corrosion, erosion and wear is an intense field of research. The technique involves injection of the powder into a plasma flame, melting, acceleration of the powder particles, impact and bonding with the substrate. Feedstock powders of metals, alloys and ceramics for thermal spray applications have to meet several requirements. Particle shape, size and its distribution, powder flow characteristics and density are the important factors to be considered in order to ensure high spray efficiency and better coating properties. For smooth and uniform feeding of powders into plasma jet, the powder particles have to be spherical in shape. High temperatures and steep temperatures present in thermal plasma is exploited to spheroidize particles in the present investigation. Nickel powder particles in the size range from 40–100 m were spheroidized using plasma processing. SEM and optical micrographs showed spherical shape of processed particles.

  3. Microwave-assisted synthesis and characterization of nickel ferrite nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Carpenter, Gopal; Sen, Ravindra; Gupta, Nitish, E-mail: nitish.nidhi75@gmail.com [Department of Applied Chemistry, Shri G. S. Institute of Technology and Science, Indore Madhyapradesh (India); Malviya, Nitin [Department of Applied Physics, Shri G. S. Institute of Technology and Science, Indore Madhyapradesh (India)

    2015-08-28

    Nickel ferrite nanoparticles (NiFe{sub 2}O{sub 4}) were successfully prepared by microwave-assisted combustion method (MWAC) using citric Electron acid as a chelating agent. NiFe{sub 2}O{sub 4} nanoparticles were characterized by X-ray diffraction (XRD) pattern, Scanning Microscopy (SEM), Fourier transform infrared (FTIR) and UV-Visible techniques. XRD analysis revealed that NiFe{sub 2}O{sub 4} nanoparticles have spinel cubic structure with the average crystalline size of 26.38 nm. SEM analysis revealed random and porous structural morphology of particles and FTIR showed absorption bands related to octahedral and tetrahedral sites, in the range 400–600cm{sup −1} which strongly favor the formation of NiFe{sub 2}O{sub 4} nanoparticles. The optical band gap is determined by UV Visible method and found to be 5.4 eV.

  4. Replication of prions in differentiated muscle cells.

    Science.gov (United States)

    Herbst, Allen; Aiken, Judd M; McKenzie, Debbie

    2014-01-01

    We have demonstrated that prions accumulate to high levels in non-proliferative C2C12 myotubes. C2C12 cells replicate as myoblasts but can be differentiated into myotubes. Earlier studies indicated that C2C12 myoblasts are not competent for prion replication. (1) We confirmed that observation and demonstrated, for the first time, that while replicative myoblasts do not accumulate PrP(Sc), differentiated post-mitotic myotube cultures replicate prions robustly. Here we extend our observations and describe the implication and utility of this system for replicating prions.

  5. Regular sub-wavelength surface structures induced by femtosecond laser pulses on nickel

    Science.gov (United States)

    Qi, Litao

    2015-02-01

    In this research, the formation of laser-induced periodic surface structures (LIPSS) on the nickel surface by femtosecond laser pulses was investigated. In the experiment, we used a commercially available amplified Ti:sapphire laser system that generated 164 fs laser pulses with a maximum pulse energy (Ep) of 1 mJ at a 1 kHz repetition rate and with a central wavelength λ= 780 nm. To obtain a fine periodic ordering of surface nanostructures, the laser beam, through a 0.2 mm pinhole aperture positioned near the 10× objective lens, was focused onto the sample. The samples were mounted on an XYZ-translation stage and irradiated in static and line-scanning experiment. The morphology of the induced periodic structure was examined by scanning electron microscopy. The surface profile was measured by atomic force microscopy. LIPSS with a period of around 700 nm entirely covered the irradiated area. Large area of LIPSS in the nickel surface was produced in line-scanning experiment. The mechanism of the formation of LIPSS in the entire irradiated area in static irradiation was discussed. The function of a 0.2 mm pinhole aperture was studied. The regular LIPSS on the nickel surface changed the optical property of the surface. The regular LIPSS on nickel surface could be also applied on the micro-mould fabrication.

  6. Replication and characterization of the compound eye of a fruit fly for imaging purpose

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hefu [State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, No. 3888, Dongnanhu Road, Changchun, Jilin (China); University of Chinese Academy of Sciences, Beijing 10039 (China); Gong, Xianwei; Ni, Qiliang; Zhao, Jingli; Zhang, Hongsheng; Wang, Taisheng [State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, No. 3888, Dongnanhu Road, Changchun, Jilin (China); Yu, Weixing, E-mail: yuwx@szu.edu.cn [Insititue of Micro and Nano Optics, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060 (China)

    2014-10-06

    In this work, we report the replication and characterization of the compound eye of a fruit fly for imaging purpose. In the replication, soft lithography method was employed to replicate the compound eye of a fruit fly into a UV-curable polymer. The method was demonstrated to be effective and the compound eye is replicated into the polymer (NOA78) where each ommatidium has a diameter of about 30 μm and a sag height of about 7 μm. To characterize its optical property, the point spread function of the compound eye was tested and a NA of 0.386 has been obtained for the replicated polymeric ommatidium. Comparing with the NA of a real fruit fly ommatidium which was measured to be about 0.212, the replicated polymeric ommatidium has a much larger NA due to the refractive index of NOA78 is much higher than that of the material used to form the real fruit fly ommatidium. Furthermore, the replicated compound eye was used to image a photomask patterned with grating structures to test its imaging property. It is shown that the grating with a line width of 20 μm can be clearly imaged. The image of the grating formed by the replicated compound eye was shrunk by about 10 times and therefore a line width of about 2.2 μm in the image plane has been obtained, which is close to the diffraction limited resolution calculated through the measured NA. In summary, the replication method demonstrated is effective and the replicated compound eye has the great potential in optical imaging.

  7. Replication and characterization of the compound eye of a fruit fly for imaging purpose

    Science.gov (United States)

    Li, Hefu; Gong, Xianwei; Ni, Qiliang; Zhao, Jingli; Zhang, Hongsheng; Wang, Taisheng; Yu, Weixing

    2014-10-01

    In this work, we report the replication and characterization of the compound eye of a fruit fly for imaging purpose. In the replication, soft lithography method was employed to replicate the compound eye of a fruit fly into a UV-curable polymer. The method was demonstrated to be effective and the compound eye is replicated into the polymer (NOA78) where each ommatidium has a diameter of about 30 μm and a sag height of about 7 μm. To characterize its optical property, the point spread function of the compound eye was tested and a NA of 0.386 has been obtained for the replicated polymeric ommatidium. Comparing with the NA of a real fruit fly ommatidium which was measured to be about 0.212, the replicated polymeric ommatidium has a much larger NA due to the refractive index of NOA78 is much higher than that of the material used to form the real fruit fly ommatidium. Furthermore, the replicated compound eye was used to image a photomask patterned with grating structures to test its imaging property. It is shown that the grating with a line width of 20 μm can be clearly imaged. The image of the grating formed by the replicated compound eye was shrunk by about 10 times and therefore a line width of about 2.2 μm in the image plane has been obtained, which is close to the diffraction limited resolution calculated through the measured NA. In summary, the replication method demonstrated is effective and the replicated compound eye has the great potential in optical imaging.

  8. DNA replication stress: causes, resolution and disease.

    Science.gov (United States)

    Mazouzi, Abdelghani; Velimezi, Georgia; Loizou, Joanna I

    2014-11-15

    DNA replication is a fundamental process of the cell that ensures accurate duplication of the genetic information and subsequent transfer to daughter cells. Various pertubations, originating from endogenous or exogenous sources, can interfere with proper progression and completion of the replication process, thus threatening genome integrity. Coordinated regulation of replication and the DNA damage response is therefore fundamental to counteract these challenges and ensure accurate synthesis of the genetic material under conditions of replication stress. In this review, we summarize the main sources of replication stress and the DNA damage signaling pathways that are activated in order to preserve genome integrity during DNA replication. We also discuss the association of replication stress and DNA damage in human disease and future perspectives in the field. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

  9. Replication Stress: A Lifetime of Epigenetic Change

    Directory of Open Access Journals (Sweden)

    Simran Khurana

    2015-09-01

    Full Text Available DNA replication is essential for cell division. Challenges to the progression of DNA polymerase can result in replication stress, promoting the stalling and ultimately collapse of replication forks. The latter involves the formation of DNA double-strand breaks (DSBs and has been linked to both genome instability and irreversible cell cycle arrest (senescence. Recent technological advances have elucidated many of the factors that contribute to the sensing and repair of stalled or broken replication forks. In addition to bona fide repair factors, these efforts highlight a range of chromatin-associated changes at and near sites of replication stress, suggesting defects in epigenome maintenance as a potential outcome of aberrant DNA replication. Here, we will summarize recent insight into replication stress-induced chromatin-reorganization and will speculate on possible adverse effects for gene expression, nuclear integrity and, ultimately, cell function.

  10. Judicious use of kinetin to improve growth and yield of rice in nickel contaminated soil.

    Science.gov (United States)

    Nazir, Hina; Asghar, Hafiz Naeem; Zahir, Zahir Ahmad; Akhtar, Muhammad Javed; Saleem, Muhammad

    2016-01-01

    The present study was conducted to evaluate the effect of kinetin on growth and yield of rice in the presence and absence of nickel contamination. Rice seedlings were dipped in kinetin solution (10(-3), 10(-4) and 10 M(-5)) for 2 hours and transplanted in pots having soil contaminated with nickel sulfate @ 130 mg kg(-1). Experiment was laid out according to completely randomized design with four replications. Results revealed that kinetin significantly improved growth and yield of rice grown in nickel contamination. Kinetin @ 10(-4) M showed maximum improvement in plant height, paddy yield, 1000 grain weight, number of tillers and panicles up to 9.76, 15.72, 11.77, 11.87, and 10.90%, respectively, as compared to plants grown in contaminated soil without kinetin. Kinetin also improved the uptake of nutrients (NPK) in straw and grain of plants grown in Ni contaminated soil. Plants treated with kinetin had more concentration of Ni in shoot but less in grain compared to plants grown in Ni contaminated soil without application of kinetin. The application of kinetin can reduce stress effect on plants through improvement in the biomass of plant. This strategy could be used to increase the phytoextraction of Ni from the contaminated soil.

  11. Development of a cloud-point extraction method for copper and nickel determination in food samples

    Energy Technology Data Exchange (ETDEWEB)

    Azevedo Lemos, Valfredo [Nucleo de Quimica Analitica da Bahia (NQA), Laboratorio de Quimica Analitica (LQA), Universidade Estadual do Sudoeste da Bahia, Campus de Jequie, 45206-190 Jequie, BA (Brazil)], E-mail: vlemos@uesb.br; Selis Santos, Moacy; Teixeira David, Graciete; Vasconcelos Maciel, Mardson; Almeida Bezerra, Marcos de [Nucleo de Quimica Analitica da Bahia (NQA), Laboratorio de Quimica Analitica (LQA), Universidade Estadual do Sudoeste da Bahia, Campus de Jequie, 45206-190 Jequie, BA (Brazil)

    2008-11-30

    A new, simple and versatile cloud-point extraction (CPE) methodology has been developed for the separation and preconcentration of copper and nickel. The metals in the initial aqueous solution were complexed with 2-(2'-benzothiazolylazo)-5-(N,N-diethyl)aminophenol (BDAP) and Triton X-114 was added as surfactant. Dilution of the surfactant-rich phase with acidified methanol was performed after phase separation, and the copper and nickel contents were measured by flame atomic absorption spectrometry. The variables affecting the cloud-point extraction were optimized using a Box-Behnken design. Under the optimum experimental conditions, enrichment factors of 29 and 25 were achieved for copper and nickel, respectively. The accuracy of the method was evaluated and confirmed by analysis of the followings certified reference materials: Apple Leaves, Spinach Leaves and Tomato Leaves. The limits of detection expressed to solid sample analysis were 0.1 {mu}g g{sup -1} (Cu) and 0.4 {mu}g g{sup -1} (Ni). The precision for 10 replicate measurements of 75 {mu}g L{sup -1} Cu or Ni was 6.4 and 1.0, respectively. The method has been successfully applied to the analysis of food samples.

  12. Nanodisperse Nickel Ferrite: Methods of Production, Structure and Magnetic Properties

    National Research Council Canada - National Science Library

    N Zaporina; J Grabis; M Maiorov; A Krumina; G Heidemane; D Bocharov

    2012-01-01

      Nanodisperse Nickel Ferrite: Methods of Production, Structure and Magnetic Properties The nickel ferrite nanoparticles were prepared using combustion synthesis and plasma chemical synthesis based on evaporation of coarse-grained...

  13. THE LOCAL LASER-STIMULATED ELECTRODEPOSITION OF THE NICKEL

    Directory of Open Access Journals (Sweden)

    V. A. Zabludovskyi

    2009-12-01

    Full Text Available The mask-free method for obtaining the local nickel coatings using laser radiation is developed. The parameters of local nickel coatings are calculated. The rate of electroplating process is estimated.

  14. Mechanical Properties of Electrolyte Jet Electrodeposited Nickel Foam

    Directory of Open Access Journals (Sweden)

    Jinsong Chen

    2013-07-01

    Full Text Available Principles of the preparation of nickel foam by electrolyte jet electrodeposition were introduced, Nickel foam samples with different porosity were fabricated. Effect of different porosity on microhardness and uniaxial tensile properties of nickel foam was discussed. The results show that the microhardness of nickel foam is 320~400 HV, lower than entitative metal clearly. The lower the porosity of nickel foam, the higher the microhardness is. During the process of uniaxial tensile, nickel foam is characterized by three distinct regions, e.g. elastic deforming region, plastic plateau region and densification region. The higher the porosity of nickel foam, the lower the plastic plateau and the poorer the strength of nickel foam, accordingly

  15. 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.

  16. Zunyi Molybdenum & Nickel Mining Enterprises Are Still in Suspension Status

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    According to the 2015 mid-year report of Tiancheng Holding,because Guizhou Province is still enforcing policy regulation&environmental; protection policy for molybdenum&nickel; mining industry,currently all molybdenum and nickel mining

  17. Homocoupling of Aryl Bromides Catalyzed by Nickel Chloride in Pyridine

    Institute of Scientific and Technical Information of China (English)

    TAO, Xiao-Chun; ZHOU, Wei; ZHANG, Yue-Ping; DAI, Chun-ya; SHEN, Dong; HUANG, Mei

    2006-01-01

    Pyridine was used as a solvent for homocoupling of aryl bromides catalyzed by nickel chloride/triarylphosphine in the presence of zinc and recycled easily. Triphenylphosphine was the best ligand for nickel in this coupling reaction.

  18. Recycling of Spent Nickel-Cadmium Batteries

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A technique for recycling spent nickel-cadmium batteries, which makes separation of cadmium and nickel possible, is developed by laboratory-scale experiments. NH3-H2CO3 aqueous solution was used in this leaching technique. Since neutralization and/or solvent extraction were not required in the separation procedure of nickel and cadmium, the closed systemization of the process becomes possible. Experimental results show that, (1) if the NH3 concentration of leaching solution is sufficiently high and the ratio of H2CO3 to NH3 is properly adjusted, both Ni(OH)2 and Cd(OH)2 react with NH3 and quickly dissolve into leaching solution, and (2) Ni(OH)2 can be converted into insoluble NiO by calcination at 500€癈, and CdO from Cd(OH)2 by calcination maintains good solubility in NH3-H2CO3 aqueous solution. As a conclusion, the recycling technique characterized by two step leaching can be developed based on such changes in dissolution behavior by calcination. Meanwhile, the yields of 99.8% for nickel and 97.6% for cadmium are obtained, and the purities of recovered nickel and cadmium are 99.9% and 98.6%, respectively.

  19. Numerous dilemmas surrounding the 1917 nickel coins

    Directory of Open Access Journals (Sweden)

    Pantelić Svetlana

    2017-01-01

    Full Text Available The Law on Extraordinary Loans Amounting to 200 Million Dinars and the Minting of Silver and Nickel Coins in 1916 was the legal basis for minting the 5-, 10-, and 20-para nickel coins of the Kingdom of Serbia featuring the year 1917 as their minting year. Some authors believe that these coins were minted in the Minting House in Paris, whereas the others agree that they were certainly minted in France, but in a still unidentified minting house. There are authors who in recent reference literature underline the possibility of their minting in the USA Gorham Company, in Providence, Rhode Island. These coins had all the characteristics of the nickel coins of the Kingdom of Serbia from 1883, 1884, 1904 and 1912. Although, according to the Law, the Minister of Finance was authorized to mint 10 million dinars of these nickel coins, only 5 million pieces in each denomination were actually minted, in the total nominal value of just 1,750,000 dinars. The general opinion is that after the war only a small amount of these nickel coins reached Serbia, because the ships transporting the Serbian coins from the minting house sank on their way. The only varying aspect in this explanation is the location from which the ships were sailing towards Corfu, i.e. from the USA or from France. These coins stopped being legal tender as of 30 November 1931.

  20. NICKEL AS AN ALTERNATIVE AUTOMOTIVE BODY MATERIAL

    Directory of Open Access Journals (Sweden)

    T. Joseph Sahaya Anand

    2012-06-01

    Full Text Available The study of the thermal, chemical and mechanical properties of pure nickel as an alternative automotive body material is presented in this paper. Current automotive components mainly use steel as the body material. Due to the increasing demand for high performance and related issues, interest is moving towards alternative materials to steel. The hardness values of both heat-treated and non-heat treated pure nickel do not change after annealing; the hardness values are in the range of 118 to 123 HV. As the annealing temperature increases, the ultimate tensile strength, yield strength and Young’s modulus decrease, which indicates that the ductility increases. The highest ultimate tensile strength of pure nickel at 300 °C annealed temperature is 758.78 MPa. X-ray diffraction (XRD studies confirmed pure nickel as a face centred cubic (FCC structure with a lattice constant measured as 0.3492 nm for the unannealed sample, which increases to 0.3512 nm for the annealed samples. The corrosion rate of both annealed and non-heat treated pure nickel is in the range of 0.0266 to 0.048 mm/year.

  1. Optics/Optical Diagnostics Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Optics/Optical Diagnostics Laboratory supports graduate instruction in optics, optical and laser diagnostics and electro-optics. The optics laboratory provides...

  2. Optical substrate materials for synchrotron radiation beamlines

    Energy Technology Data Exchange (ETDEWEB)

    Howells, M.R. [Lawrence Berkeley National Lab., CA (United States). Advanced Light Source; Paquin, R.A. [Univ. of Arizona, Tucson, AZ (United States). Optical Sciences Center

    1997-06-01

    The authors consider the materials choices available for making optical substrates for synchrotron radiation beam lines. They find that currently the optical surfaces can only be polished to the required finish in fused silica and other glasses, silicon, CVD silicon carbide, electroless nickel and 17-4 PH stainless steel. Substrates must therefore be made of one of these materials or of a metal that can be coated with electroless nickel. In the context of material choices for mirrors they explore the issues of dimensional stability, polishing, bending, cooling, and manufacturing strategy. They conclude that metals are best from an engineering and cost standpoint while the ceramics are best from a polishing standpoint. They then give discussions of specific materials as follows: silicon carbide, silicon, electroless nickel, Glidcop{trademark}, aluminum, precipitation-hardening stainless steel, mild steel, invar and superinvar. Finally they summarize conclusions and propose ideas for further research.

  3. Organic devices based on nickel nanowires transparent electrode

    OpenAIRE

    Jeongmo Kim; Wilson Jose da Silva; Abd. Rashid bin Mohd Yusoff; Jin Jang

    2016-01-01

    Herein, we demonstrate a facile approach to synthesize long nickel nanowires and discuss its suitability to replace our commonly used transparent electrode, indium-tin-oxide (ITO), by a hydrazine hydrate reduction method where nickel ions are reduced to nickel atoms in an alkaline solution. The highly purified nickel nanowires show high transparency within the visible region, although the sheet resistance is slightly larger compared to that of our frequently used transparent electrode, ITO. A...

  4. Nickel acts as an adjuvant during cobalt sensitization.

    Science.gov (United States)

    Bonefeld, Charlotte Menné; Nielsen, Morten Milek; Vennegaard, Marie T; Johansen, Jeanne Duus; Geisler, Carsten; Thyssen, Jacob P

    2015-03-01

    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 investigated these effects by using a recently developed mouse model. Mice were epicutaneously sensitized with i) nickel alone, ii) nickel in the presence of cobalt, iii) cobalt alone, or iv) cobalt in the presence of nickel, and then followed by challenge with either nickel or cobalt alone. We found that sensitization with nickel alone induced more local inflammation than cobalt alone as measured by increased ear-swelling. Furthermore, the presence of nickel during sensitization to cobalt led to a stronger challenge response to cobalt as seen by increased ear-swelling and increased B and T cell responses 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 against cobalt more than the presence of cobalt during sensitization to nickel affected the challenge response against nickel. Taken together, our study demonstrates that sensitization with a mixture of nickel and cobalt leads to an increased immune response to both nickel and cobalt, especially to cobalt, and furthermore that the adjuvant effect appears to correlate with the inflammatory properties of the allergen. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  5. Nickel concentrations in fingernails as a measure of occupational exposure to nickel

    DEFF Research Database (Denmark)

    Peters, K; Gammelgaard, Bente; Menné, T

    1991-01-01

    The nickel concentration in fingernails from 2 groups of people occupationally exposed to nickel was determined. In one group, comprising 83 persons moderately exposed to nickel, the mean +/- standard deviation (SD) was 29.2 micrograms/g +/- 56.7 micrograms/g and the median 13.8 micrograms/g (range...... 0.926-396 micrograms/g). In the other group, comprising 51 persons heavily exposed to nickel, the mean +/- SD was 123 micrograms/g +/- 289 micrograms/g and the median 29.9 micrograms/g (range 1.95-1770 micrograms/g). Both levels were significantly different from the normal nickel concentration...... in nails (p less than 0.001). The difference between the 2 levels was also significant (p less than 0.001). No correlation between the nickel concentration in fingernails and the duration of exposure could be demonstrated. It was concluded that the higher the nickel level in the fingernails, the greater...

  6. Synthesis and characterization of nickel oxide thin films deposited on glass substrates using spray pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Jlassi, M., E-mail: mohamedjlassilpv@yahoo.fr [Laboratoire de Photovoltaïque, Centre de Recherche et des Technologies de l’Energie, Technopole de Borj-Cédria, BP 95, 2050 Hammam-Lif (Tunisia); Sta, I. [Laboratoire de Photovoltaïque, Centre de Recherche et des Technologies de l’Energie, Technopole de Borj-Cédria, BP 95, 2050 Hammam-Lif (Tunisia); Hajji, M. [Laboratoire de Photovoltaïque, Centre de Recherche et des Technologies de l’Energie, Technopole de Borj-Cédria, BP 95, 2050 Hammam-Lif (Tunisia); Ecole Nationale d’Electronique et des Communications de Sfax, Technopole de Sfax, BP 1163, CP 3021 (Tunisia); Ezzaouia, H. [Laboratoire de Photovoltaïque, Centre de Recherche et des Technologies de l’Energie, Technopole de Borj-Cédria, BP 95, 2050 Hammam-Lif (Tunisia)

    2014-07-01

    A simple and inexpensive spray pyrolysis technique was employed to deposit nickel oxide (NiO) thin films from hydrated nickel chloride salt solution onto amorphous glass substrate. The as-deposited films were transparent, uniform and well adherent to the glass substrate. The effect of the substrate temperature, the volume and the concentration of the sprayed solution on the structural, optical and electrical properties was studied using X-ray diffraction, optical transmittance, four point probe, scanning electron microscopy and atomic force microscopy. The structural analyses show that all the samples have a cubic structure. It was found that the increase in the volume of sprayed solution leads to an increment in the crystallite size of NiO and improves the homogeneity of the film. Optical measurements have shown that an increase in the thickness of the layer results in a decrease in the optical transmission, but it remains higher than 70% even if the thickness exceeds 600 nm. At the same time, the optical gap decreases from 3.7 to 3.55 eV when the thickness increases from 133 to 620 nm. Low values of the electrical resistivity (less than 10 Ω cm) were obtained for thin films with thicknesses less than about 240 nm, but for higher thicknesses the resistivity increases linearly to reach about 170 Ω cm for a thickness of 620 nm.

  7. Contribution to the knowledge of nickel hydroxide electrodes. 5. Analysis and electrochemical behavior of cadmium nickel hydroxides

    Science.gov (United States)

    Bode, H.; Dennstedt, W.

    1981-01-01

    Electrochemical experiments performed at sintered and bulk electrodes show that beta nickel hydroxide contains an electrochemically inactive proportion of cadmium hydroxide of up to 10%. The electrochemically ineffective cadmium hydroxide is homogeneously dissolved in beta nickel hydroxide.

  8. 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

    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...... 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...

  9. The Prospects of China’s Nickel Resources

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    <正>After years of efforts since the 1950s, China’s development and use of the nickel resources has gained rapid progress with a relatively complete industry system established. In 2004, China’s refined nickel production reached nearly 80,000 tons, which made China the fifth largest nickel producer in the world. China’s

  10. Electrospinning of nickel oxide nanofibers: Process parameters and morphology control

    Energy Technology Data Exchange (ETDEWEB)

    Khalil, Abdullah, E-mail: akhalil@masdar.ac.ae; Hashaikeh, Raed, E-mail: rhashaikeh@masdar.ac.ae

    2014-09-15

    In the present work, nickel oxide nanofibers with varying morphology (diameter and roughness) were fabricated via electrospinning technique using a precursor composed of nickel acetate and polyvinyl alcohol. It was found that the diameter and surface roughness of individual nickel oxide nanofibers are strongly dependent upon nickel acetate concentration in the precursor. With increasing nickel acetate concentration, the diameter of nanofibers increased and the roughness decreased. An optimum concentration of nickel acetate in the precursor resulted in the formation of smooth and continuous nickel oxide nanofibers whose diameter can be further controlled via electrospinning voltage. Beyond an optimum concentration of nickel acetate, the resulting nanofibers were found to be ‘flattened’ and ‘wavy’ with occasional cracking across their length. Transmission electron microscopy analysis revealed that the obtained nanofibers are polycrystalline in nature. These nickel oxide nanofibers with varying morphology have potential applications in various engineering domains. - Highlights: • Nickel oxide nanofibers were synthesized via electrospinning. • Fiber diameter and roughness depend on nickel acetate concentration used. • With increasing nickel acetate concentration the roughness of nanofibers decreased. • XRD and TEM revealed a polycrystalline structure of the nanofibers.

  11. Standard Specification for Nickel-Chromium-Molybdenum-Columbium Alloy (UNS N06625), Nickel-Chromium-Molybdenum-Silicon Alloy (UNS N06219), and Nickel-Chromium-Molybdenum-Tungsten Alloy (UNS N06650) Rod and Bar

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2014-01-01

    Standard Specification for Nickel-Chromium-Molybdenum-Columbium Alloy (UNS N06625), Nickel-Chromium-Molybdenum-Silicon Alloy (UNS N06219), and Nickel-Chromium-Molybdenum-Tungsten Alloy (UNS N06650) Rod and Bar

  12. 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.

  13. Thermodynamic aspects of nickel humic acid interactions

    Energy Technology Data Exchange (ETDEWEB)

    Warwick, P.; Hall, A.; King, S.J.; Zhu, J. [Loughborough Univ. (United Kingdom); Van der Lee, J. [Ecole des Mines de Paris, Centre d`Inforamtique Geologique, Fontainebleu (France)

    1998-12-31

    NiHA stability constants ({beta} values) have been derived at different temperatures from the amounts of nickel (Ni{sup 2+}) and nickel humate (NiHA), determined to be present, in equilibrated nickel humic acid mixtures at 4 C, 20 C, 40 C, 60 C and 80 C. The constants were deduced using (i) a simple Scatchard plot, (ii) a metal-humic acid charge neutralisation model and (iii) an electrostatic/discrete site complexation model as implemented in the CHESS geochemical speciation code. The derived values depended on whether bulk solution (Scatchard and Charge Neutralisation Approaches) or humic surface metal concentrations (Electrostatic Approach) were employed in the calculations. The Scatchard and Charge Neutralisation approaches were found to be mathematically equivalent. The differently derived constants and their temperature dependencies have been used to calculate corresponding thermodynamic {Delta}H, {Delta}G and {Delta}S values. The values obtained are compared and features of thermodynamic significance discussed. (orig.)

  14. Self-replication of DNA rings

    Science.gov (United States)

    Kim, Junghoon; Lee, Junwye; Hamada, Shogo; Murata, Satoshi; Ha Park, Sung

    2015-06-01

    Biology provides numerous examples of self-replicating machines, but artificially engineering such complex systems remains a formidable challenge. In particular, although simple artificial self-replicating systems including wooden blocks, magnetic systems, modular robots and synthetic molecular systems have been devised, such kinematic self-replicators are rare compared with examples of theoretical cellular self-replication. One of the principal reasons for this is the amount of complexity that arises when you try to incorporate self-replication into a physical medium. In this regard, DNA is a prime candidate material for constructing self-replicating systems due to its ability to self-assemble through molecular recognition. Here, we show that DNA T-motifs, which self-assemble into ring structures, can be designed to self-replicate through toehold-mediated strand displacement reactions. The inherent design of these rings allows the population dynamics of the systems to be controlled. We also analyse the replication scheme within a universal framework of self-replication and derive a quantitative metric of the self-replicability of the rings.

  15. 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

    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 frequency...

  16. Anodic stripping voltammetry of nickel ions and nickel hydroxide nanoparticles at boron-doped diamond electrodes

    Science.gov (United States)

    Musyarofah, N. R. R.; Gunlazuardi, J.; Einaga, Y.; Ivandini, T. A.

    2017-04-01

    Anodic stripping voltammetry (ASV) of nickel ions in phosphate buffer solution (PBS) have been investigated at boron-doped diamond (BDD) electrodes. The deposition potential at 0.1 V (vs. Ag/AgCl) for 300 s in 0.1 M PBS pH 3 was found as the optimum condition. The condition was applied for the determination of nickel contained in nickel hydroxide nanoparticles. A linear calibration curve can be achieved of Ni(OH)2-NPs in the concentration range of x to x mM with an estimated limit of detection (LOD) of 5.73 × 10-6 mol/L.

  17. Risk assessment for nickel contact allergy.

    Science.gov (United States)

    Boonchai, Waranya; Chaiwanon, Onjuta; Kasemsarn, Pranee

    2014-12-01

    Nickel is one of the most common allergens causing allergic contact dermatitis worldwide. The aim of the study was to evaluate the contributing factors to nickel contact allergy (NiCA) in Asians who have a unique culture and lifestyle. We randomly selected 324 previously patch-tested patients, 162 nickel patch test (PT)-positive patients and 162 nickel PT-negative patients. The patients were telephone interviewed for their lifestyle information. Most of the nickel PT-positive patients (93.2%) were female with a mean age of 38.9 ± 13.3 years compared with the other group of nickel PT-negative patients who had a smaller proportion of females (76.5%) with an older mean age of 44.1 ± 14.9 years (P = 0.001). Multivariate analysis was able to establish that the significant risk factors for NiCA were female sex (odds ratio [OR], 6.38; 95% confidence interval [CI], 2.15-18.94), young age (OR, 0.98; 95% CI, 0.96-1.00), occupation with long periods of exposure to metal (OR, 3.08; 95% CI, 1.18-8.02), seafood (OR, 1.96; 95% CI, 1.17-3.27) and canned food consumption (OR, 3.12; 95% CI, 1.17-8.33) (P < 0.05). The adjusted factors found to associate with NiCA were female sex, young age, occupation with long periods of exposure to metal, seafood and canned food consumption.

  18. DNA Replication via Entanglement Swapping

    CERN Document Server

    Pusuluk, Onur

    2010-01-01

    Quantum effects are mainly used for the determination of molecular shapes in molecular biology, but quantum information theory may be a more useful tool to understand the physics of life. Molecular biology assumes that function is explained by structure, the complementary geometries of molecules and weak intermolecular hydrogen bonds. However, both this assumption and its converse are possible if organic molecules and quantum circuits/protocols are considered as hardware and software of living systems that are co-optimized during evolution. In this paper, we try to model DNA replication as a multiparticle entanglement swapping with a reliable qubit representation of nucleotides. In the model, molecular recognition of a nucleotide triggers an intrabase entanglement corresponding to a superposition state of different tautomer forms. Then, base pairing occurs by swapping intrabase entanglements with interbase entanglements.

  19. Diamond turning of aspheric steel molds for optics replication

    Science.gov (United States)

    Klocke, F.; Dambon, O.; Bulla, B.

    2010-02-01

    Diamond turning of steel parts is conventionally not possible due to the high tool wear. However this process would enable several different application with high economical innovative potential. One technology that enables the direct manufacturing of steel components with monocrystalline diamond is the ultrasonic assisted diamond turning process. This technology has been investigated over years within the Fraunhofer IPT and has proven its potential. Surface roughness in the range of Ra = 5 nm are reached and the diamond wear is reduced by a factor 100 or higher. Up to now this process has been investigated in lab conditions manufacturing only plane surfaces. In order to prove its industrial suitability, two relevant aspherical shapes, convex and concave respectively, have been defined and manufactured. The reached form accuracies and surface roughness values will be described in this paper.

  20. Replication of Optical Microstructures of Papilio palinurus through Biomimicry

    Science.gov (United States)

    Srinivasarao, Mohan; Crne, Matija; Sharma, Vivek; Blair, John; Park, Jung Ok; Summers, Christopher J.

    2009-03-01

    The coloration of animals in nature is sometimes based on their structure rather than pigments. Structural coloration based on diffraction, multilayer reflection, cholesteric analogues or photonic crystal-like structures is pervasive especially in the world of insects. The color of Papilio palinurus results from microbowl lined with a multilayer of air and chitin. The green color is the result of color mixing of the yellow light reflecting from the bottom of the bowl and the blue light reflecting from the sides of the bowl. We have used breath figure templated assembly as the starting point to mimic the structure of Papilio palinurus. We were able to produce microbowls which were then coated with a multilayer of alternating titanium oxide and aluminum oxide. The resulting structure exhibits the same color mixing as the original butterfly structure does.

  1. Therapeutic targeting of replicative immortality.

    Science.gov (United States)

    Yaswen, Paul; MacKenzie, Karen L; Keith, W Nicol; Hentosh, Patricia; Rodier, Francis; Zhu, Jiyue; Firestone, Gary L; Matheu, Ander; Carnero, Amancio; Bilsland, Alan; Sundin, Tabetha; Honoki, Kanya; Fujii, Hiromasa; Georgakilas, Alexandros G; Amedei, Amedeo; Amin, Amr; Helferich, Bill; Boosani, Chandra S; Guha, Gunjan; Ciriolo, Maria Rosa; Chen, Sophie; Mohammed, Sulma I; Azmi, Asfar S; Bhakta, Dipita; Halicka, Dorota; Niccolai, Elena; Aquilano, Katia; Ashraf, S Salman; Nowsheen, Somaira; Yang, Xujuan

    2015-12-01

    One of the hallmarks of malignant cell populations is the ability to undergo continuous proliferation. This property allows clonal lineages to acquire sequential aberrations that can fuel increasingly autonomous growth, invasiveness, and therapeutic resistance. Innate cellular mechanisms have evolved to regulate replicative potential as a hedge against malignant progression. When activated in the absence of normal terminal differentiation cues, these mechanisms can result in a state of persistent cytostasis. This state, termed "senescence," can be triggered by intrinsic cellular processes such as telomere dysfunction and oncogene expression, and by exogenous factors such as DNA damaging agents or oxidative environments. Despite differences in upstream signaling, senescence often involves convergent interdependent activation of tumor suppressors p53 and p16/pRB, but can be induced, albeit with reduced sensitivity, when these suppressors are compromised. Doses of conventional genotoxic drugs required to achieve cancer cell senescence are often much lower than doses required to achieve outright cell death. Additional therapies, such as those targeting cyclin dependent kinases or components of the PI3K signaling pathway, may induce senescence specifically in cancer cells by circumventing defects in tumor suppressor pathways or exploiting cancer cells' heightened requirements for telomerase. Such treatments sufficient to induce cancer cell senescence could provide increased patient survival with fewer and less severe side effects than conventional cytotoxic regimens. This positive aspect is countered by important caveats regarding senescence reversibility, genomic instability, and paracrine effects that may increase heterogeneity and adaptive resistance of surviving cancer cells. Nevertheless, agents that effectively disrupt replicative immortality will likely be valuable components of new combinatorial approaches to cancer therapy. Copyright © 2015 The Authors

  2. Important Parameters and Applications for Nickel Electroforming

    DEFF Research Database (Denmark)

    Tang, Peter Torben; Benzon, Michael Eis; Rasmussen, J.P.;

    1996-01-01

    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......H-value, temperature and the use of pulse plating and additives will be examined with respect to mechanical properties such as internal stress, material distribution and hardness. Pulse plating in a chloride and Watts nickel bath and DC plating in sulphamate bath will be discussed, as well as different methods...

  3. Dual-Anode Nickel/Hydrogen Cell

    Science.gov (United States)

    Gahn, Randall F.; Ryan, Timothy P.

    1994-01-01

    Use of two hydrogen anodes in nickel/hydrogen cell reduces ohmic and concentration polarizations contributing to internal resistance, yielding cell with improved discharging performance compared to single-anode cell. Dual-anode concept incorporated into nickel/hydrogen cells of individual pressure-vessel type (for use aboard spacecraft) and common pressure-vessel type, for use on Earth to store electrical energy from photovoltaic sources, "uninterruptible" power supplies of computer and telephone systems, electric vehicles, and load leveling on power lines. Also applicable to silver/hydrogen and other metal/gas batteries.

  4. Effect of nano-size nickel particles on wear resistance and high temperature oxidation resistance of ultrafine ceramic coating

    Institute of Scientific and Technical Information of China (English)

    古一; 夏长清; 李佳; 吴安如

    2004-01-01

    In order to improve the wear resistance and high temperature oxidation resistance of titanium and titanium alloy, the high temperature ultra fine ceramic coating containing nano-size nickel particles was prepared by flow coat method on the surface of industrially pure titanium TB1-0. The effects of nano-size nickel particles on the wear resistance and high temperature oxidation resistance of coating substrate system were investigated through oxidation kinetics experiment and wear resistance test. The morphologies of the specimens were examined by means of optical microscopy, scanning electron microscopy and X-ray diffraction. The results show that the high temperature ultra fine ceramic coating has notable protection effect on industrially pure titanium TB1-0 from oxidation. The oxidation and wear resistance properties of the coating can be effectively improved by adding nano-size nickel particles. The decreases from 1. 1 to 0. 6 by adding nano-size nickel particles, and the coating containing 10% (mass fraction) nano-size nickel shows the optimum properties.

  5. Regulation of Unperturbed DNA Replication by Ubiquitylation

    Directory of Open Access Journals (Sweden)

    Sara Priego Moreno

    2015-06-01

    Full Text Available Posttranslational modification of proteins by means of attachment of a small globular protein ubiquitin (i.e., ubiquitylation represents one of the most abundant and versatile mechanisms of protein regulation employed by eukaryotic cells. Ubiquitylation influences almost every cellular process and its key role in coordination of the DNA damage response is well established. In this review we focus, however, on the ways ubiquitylation controls the process of unperturbed DNA replication. We summarise the accumulated knowledge showing the leading role of ubiquitin driven protein degradation in setting up conditions favourable for replication origin licensing and S-phase entry. Importantly, we also present the emerging major role of ubiquitylation in coordination of the active DNA replication process: preventing re-replication, regulating the progression of DNA replication forks, chromatin re-establishment and disassembly of the replisome at the termination of replication forks.

  6. Chromosome replication and segregation in bacteria.

    Science.gov (United States)

    Reyes-Lamothe, Rodrigo; Nicolas, Emilien; Sherratt, David J

    2012-01-01

    In dividing cells, chromosome duplication once per generation must be coordinated with faithful segregation of newly replicated chromosomes and with cell growth and division. Many of the mechanistic details of bacterial replication elongation are well established. However, an understanding of the complexities of how replication initiation is controlled and coordinated with other cellular processes is emerging only slowly. In contrast to eukaryotes, in which replication and segregation are separate in time, the segregation of most newly replicated bacterial genetic loci occurs sequentially soon after replication. We compare the strategies used by chromosomes and plasmids to ensure their accurate duplication and segregation and discuss how these processes are coordinated spatially and temporally with growth and cell division. We also describe what is known about the three conserved families of ATP-binding proteins that contribute to chromosome segregation and discuss their inter-relationships in a range of disparate bacteria.

  7. A Comparative Study of Biodegradation of Nickel and Chromium from Space Maintainers: An in vitro Study

    Science.gov (United States)

    Anand, Ashish; Sharma, Arun; Kumar, Piush; Sachdeva, Shobhit; Sachdev, Vinod

    2015-01-01

    ABSTRACT Objective: The aim of the study was to compare and evaluate the in vitro biodegradation of nickel and chromium from space maintainers, made of three different companies, i.e (Dantaurum, Rocky mountain and Dtech) in artificial saliva. Materials and methods: The study comprised of 30 space maintainers out of which 10 were fabricated using Dantaurum, 10 using Rocky mountain and 10 using Dtech band materials. Stainless steel wire (Dantaurum, Rocky mountain and Konark) was used for making loops and Leone solder and flux was used for soldering. Each group was further divided into four subgroups containing 1, 2, 3 and 4 space maintainers respectively. The space maintainers in each subgroup were placed in separate glass beakers containing 100 ml of artificial saliva at 37°C for 4 weeks. Salivary samples from each beaker was analyzed for nickel and chromium ions separately on days 1, 7, 14, 21 and 28 days using inductively coupled plasma-optical emission spectrophotometer. Results: Total release of nickel and chromium from all band and loop space maintainers ranged from 0.020 to 1.524 ppm and 0.002 to 0.289 ppm respectively. The release of nickel and chromium between the groups and within the groups was not significant (p space maintainers made of Dantaurum, Rocky mountain and Dtech which could cause any toxicity. How to cite this article: Anand A, Sharma A, Kumar P, Sandhu M, Sachdeva S, Sachdev V. A Comparative Study of Biodegradation of Nickel and Chromium from Space Maintainers: An in vitro Study. Int J Clin Pediatr Dent 2015; 8(1):37-41. PMID:26124579

  8. Sol-gel synthesis and behaviour of nickel containing ZnO nanoparticles.

    Science.gov (United States)

    Thota, Subhash; Kumar, Jitendra

    2008-08-01

    An attempt has been made to synthesize nickel (up to 5 at%) containing ZnO diluted magnetic semiconductors by sol-gel process using zinc acetate dihydrate, nickel acetate tetrahydrate and oxalic acid as precursors and ethanol as solvent. The process comprises of gel formation, digestion at 80 degrees C for 24 h to obtain oxalate and calcination at 400 degrees C or above for 2 h for decomposition to oxide. The resulting powders correspond to wurtzite hexagonal structure similar to that of pure ZnO and contain nanoparticles of average diameter decreasing with (i) decrease of calcination temperature and (ii) rise in nickel content (range being 13-29 nm). Evidence has been advanced to suggest occupancy of Ni2+ ions in Zn2+ sites (i.e., in the centre of O2- tetrahedra) without any secondary phase. Further, the first nearest neighbor average distance of Ni2+ ions vary inversely as cube root of nickel content ('x'). Optical absorption peaks are attributed to transitions from 3T1 (F) to 3A2(F), 3T1(P) and 3T2(F) states of Ni2+ ion (3d8 configuration). The bifurcation in magnetization versus temperature curves under zero field cooled (ZFC) and field cooled (FC) conditions indicates the presence of magnetic nanoparticles with the blocking temperature (TB) decreasing with increase in nickel content; typical values being 70 and 30 K for 1 and 5 at% of Ni2+ containing ZnO, respectively. The observations of (i) hysteresis loops both at 10 and 298 K and (ii) shift in electron spin resonance (ESR) spectra from the free electron position enunciate ferromagnetic nature of Zn(1-x)Ni(x)O nanoparticles at room temperature.

  9. Long Life Nickel Electrodes for Nickel-Hydrogen Cells: Fiber Substrates Nickel Electrodes

    Science.gov (United States)

    Rogers, Howard H.

    2000-01-01

    Samples of nickel fiber mat electrodes were investigated over a wide range of fiber diameters, electrode thickness, porosity and active material loading levels. Thickness' were 0.040, 0.060 and 0.080 inches for the plaque: fiber diameters were primarily 2, 4, and 8 micron and porosity was 85, 90, and 95%. Capacities of 3.5 in. diameter electrodes were determined in the flooded condition with both 26 and 31% potassium hydroxide solution. These capacity tests indicated that the highest capacities per unit weight were obtained at the 90% porosity level with a 4 micron diameter fiber plaque. It appeared that the thinner electrodes had somewhat better performance, consistent with sintered electrode history. Limited testing with two-positive-electrode boiler plate cells was also carried out. Considerable difficulty with constructing the cells was encountered with short circuits the major problem. Nevertheless, four cells were tested. The cell with 95% porosity electrodes failed during conditioning cycling due to high voltage during charge. Discharge showed that this cell had lost nearly all of its capacity. The other three cells after 20 conditioning cycles showed capacities consistent with the flooded capacities of the electrodes. Positive electrodes made from fiber substrates may well show a weight advantage of standard sintered electrodes, but need considerably more work to prove this statement. A major problem to be investigated is the lower strength of the substrate compared to standard sintered electrodes. Problems with welding of leads were significant and implications that the electrodes would expand more than sintered electrodes need to be investigated. Loading levels were lower than had been expected based on sintered electrode experiences and the lower loading led to lower capacity values. However, lower loading causes less expansion and contraction during cycling so that stress on the substrate is reduced.

  10. Semiconservative replication in the quasispecies model

    Science.gov (United States)

    Tannenbaum, Emmanuel; Deeds, Eric J.; Shakhnovich, Eugene I.

    2004-06-01

    This paper extends Eigen’s quasispecies equations to account for the semiconservative nature of DNA replication. We solve the equations in the limit of infinite sequence length for the simplest case of a static, sharply peaked fitness landscape. We show that the error catastrophe occurs when μ , the product of sequence length and per base pair mismatch probability, exceeds 2 ln [2/ ( 1+1/k ) ] , where k>1 is the first-order growth rate constant of the viable “master” sequence (with all other sequences having a first-order growth rate constant of 1 ). This is in contrast to the result of ln k for conservative replication. In particular, as k→∞ , the error catastrophe is never reached for conservative replication, while for semiconservative replication the critical μ approaches 2 ln 2 . Semiconservative replication is therefore considerably less robust than conservative replication to the effect of replication errors. We also show that the mean equilibrium fitness of a semiconservatively replicating system is given by k ( 2 e-μ/2 -1 ) below the error catastrophe, in contrast to the standard result of k e-μ for conservative replication (derived by Kimura and Maruyama in 1966). From this result it is readily shown that semiconservative replication is necessary to account for the observation that, at sufficiently high mutagen concentrations, faster replicating cells will die more quickly than more slowly replicating cells. Thus, in contrast to Eigen’s original model, the semiconservative quasispecies equations are able to provide a mathematical basis for explaining the efficacy of mutagens as chemotherapeutic agents.

  11. Effects of repeated skin exposure to low nickel concentrations

    DEFF Research Database (Denmark)

    Nielsen, N H; Menné, T; Kristiansen, J

    1999-01-01

    and nickel allergy, either on normal or on SLS-treated forearm skin. The present study strongly suggests that the changes observed were specific to nickel exposure. Standardized methods to assess trace to moderate nickel exposure on the hands, and the associated effects in nickel-sensitized subjects...... with a group of patients who immersed a finger into water. The nickel concentrations used also provoked significant inflammatory skin changes on sodium lauryl sulphate (SLS)-treated forearm skin of the patients, whereas inflammatory skin changes were not observed in healthy volunteers without hand eczema...

  12. Nickel phosphate molecular sieve as electrochemical capacitors material

    Science.gov (United States)

    Yang, Jing-He; Tan, Juan; Ma, Ding

    2014-08-01

    The nickel phosphate molecular sieve VSB-5 as an electrode material for supercapacitors is investigated by cyclic voltammetry (CV) and chronopotentiometry in alkaline media. The VSB-5 shows high specific capacitance and excellent cycling stability. The specific capacitance of VSB-5 is 2740 F g-1 at a current density of 3 A g-1 and there is no significant reduction in Coulombic efficiency after 3000 cycles at 30 A g-1. In comparison with mesoporous nickel phosphate NiPO, porous nickel hydroxide and mesoporous nickel oxide, this remarkable electrochemical performance of VSB-5 will make nickel phosphate material a promising new electrode material for high performance supercapacitors.

  13. Regulation of chromosomal replication in Caulobacter crescentus.

    Science.gov (United States)

    Collier, Justine

    2012-03-01

    The alpha-proteobacterium Caulobacter crescentus is characterized by its asymmetric cell division, which gives rise to a replicating stalked cell and a non-replicating swarmer cell. Thus, the initiation of chromosomal replication is tightly regulated, temporally and spatially, to ensure that it is coordinated with cell differentiation and cell cycle progression. Waves of DnaA and CtrA activities control when and where the initiation of DNA replication will take place in C. crescentus cells. The conserved DnaA protein initiates chromosomal replication by directly binding to sites within the chromosomal origin (Cori), ensuring that DNA replication starts once and only once per cell cycle. The CtrA response regulator represses the initiation of DNA replication in swarmer cells and in the swarmer compartment of pre-divisional cells, probably by competing with DnaA for binding to Cori. CtrA and DnaA are controlled by multiple redundant regulatory pathways that include DNA methylation-dependent transcriptional regulation, temporally regulated proteolysis and the targeting of regulators to specific locations within the cell. Besides being critical regulators of chromosomal replication, CtrA and DnaA are also master transcriptional regulators that control the expression of many genes, thus connecting DNA replication with other events of the C. crescentus cell cycle. Copyright © 2012 Elsevier Inc. All rights reserved.

  14. Comparison of three replication strategies in complex multicellular organisms: Asexual replication, sexual replication with identical gametes, and sexual replication with distinct sperm and egg gametes

    Science.gov (United States)

    Tannenbaum, Emmanuel

    2008-01-01

    This paper studies the mutation-selection balance in three simplified replication models. The first model considers a population of organisms replicating via the production of asexual spores. The second model considers a sexually replicating population that produces identical gametes. The third model considers a sexually replicating population that produces distinct sperm and egg gametes. All models assume diploid organisms whose genomes consist of two chromosomes, each of which is taken to be functional if equal to some master sequence, and defective otherwise. In the asexual population, the asexual diploid spores develop directly into adult organisms. In the sexual populations, the haploid gametes enter a haploid pool, where they may fuse with other haploids. The resulting immature diploid organisms then proceed to develop into mature organisms. Based on an analysis of all three models, we find that, as organism size increases, a sexually replicating population can only outcompete an asexually replicating population if the adult organisms produce distinct sperm and egg gametes. A sexual replication strategy that is based on the production of large numbers of sperm cells to fertilize a small number of eggs is found to be necessary in order to maintain a sufficiently low cost for sex for the strategy to be selected for over a purely asexual strategy. We discuss the usefulness of this model in understanding the evolution and maintenance of sexual replication as the preferred replication strategy in complex, multicellular organisms.

  15. An electron microscopy examination of primary recrystallization in TD-nickel.

    Science.gov (United States)

    Petrovic, J. J.; Ebert, L. J.

    1972-01-01

    Primary recrystallization in TD-nickel 1 in. bar has previously been regarded as the process by which the initial fine grain structure is converted to a coarse grain size (increases in grain size by 500 times) under suitable deformation and annealing conditions. This process is dependent on deformation mode. While it occurs readily after rolling transverse to the bar axis and annealing (800 C), it is completely inhibited by longitudinal rolling and swaging deformations, even for very high (1320 C) annealing temperatures. A transmission electron microscopy examination of deformation and annealing substructures indicates that primary recrystallization in TD-nickel 1 in. bar actually occurs on the sub-light optical level, to produce a grain structure similar in size to the initial fine grained state.

  16. Oxygen Evolution at Nickel Hydroxide Films Co-deposited Light Rare Earth Elements

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Composite nickel hydroxide films were prepared by cathodic co-electrodeposition from metal nitrate solution and characterized by cyclic voltammetry in 1.0 mol/L KOH solution. The codeposited light rare earth elements were lanthanum, cerium, praseodymium and neodymium. The films were analyzed by spectrophotometry and optical transmission. The results of the cyclic voltammetry in 1.0 mol/L KOH solution showed that the current density for oxygen evolution at the film electrode was affected by the co-deposited rare earth metal ions in the film. About 20 mA/cm2 increase of current density for oxygen evolution was found when the film was obtained from the solution with cerium (7% v/v) and nickel (93% v/v) nitrate. The effects of galvanostatic cathodic current density for the film formation on the oxygen evolution at the film electrodes from the alkaline were discussed.

  17. Structure of ultradisperse nickel particles produced by the thermolysis of nickel formate-monoethanol amine complexes

    Energy Technology Data Exchange (ETDEWEB)

    Khvorov, M.M.; Dudchenko, A.K.; Khimchenko, IU.I.

    1986-05-01

    Histograms of the size distribution of ultradisperse nickel particles produced by the thermolysis of amine complexes are plotted using dark-field and light-field electron microscopy data. It is found that the size distribution can be adequately approximated by logarithmically probabilistic functions. The ultradisperse nickel particles feature several types of structure, i.e., faceted stable single crystals coated by an organic film, small aggregates of such crystals, large stable globules, and hexahedral and trihedral crystals. 8 references.

  18. Characterization of Surface Film Growth During Electrochemical Process: Nickel/Nickel Alloys in Seawater

    Science.gov (United States)

    2006-11-01

    of the structure of nickel electrodes during hydrogen evolution in sulfuric acid electrolysis. Those investigators reported that by x-ray diffraction...to a constant potential of - 500 mV, respectively. The diffraction patterns were analyzed. It was found that, apart from the initial hydrogen gas...Acual XPS sOWr c 4C opy+ MOf acWualXpS spectagenertedby cuvefztthW DP -_4 D.COIWohI•MIpeaksof thwcurvefitted XPS spectra Figure 73. Nickel peaks

  19. Nickel patch test reactivity and the menstrual cycle

    DEFF Research Database (Denmark)

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

    1994-01-01

    Premenstrual exacerbation of allergic contact dermatitis and varying allergic patch test responses have been reported at different points of the period. Using a dilution series of nickel sulphate, we studied the variation in patch test reactivity in nickel allergic women in relation...... to the 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...... an increased nickel sensitivity at the second patch test (0.02 nickel sulphate patch tests premenstrually in 20 nickel allergic women, but we found that elicitation...

  20. Atmospheric leaching of nickel and cobalt from nickel saprolite ores using the Starved Acid Leaching Technology

    Science.gov (United States)

    Dreisinger, David

    2017-01-01

    There is great potential to recover nickel from below cut-off grade nickel saprolite ores using the Starved Acid Leach Technology (SALT). Nickel saprolite ores are normally mined as feed to Fe-Ni smelters or Ni matte smelting operations. The smelting processes typically require high Ni cut-off grades of 1.5 to 2.2% Ni, depending on the operation. These very high cutoff grades result in a significant portion of the saprolite profile being regarded as "waste" and hence having little to no value. The below cut-off grade (waste) material can be processed by atmospheric acid leaching with "starvation" levels of acid addition. The leached nickel and cobalt may be recovered as a mixed hydroxide (or alternate product). The mixed hydroxide may be added to the saprolite smelting operation feed system to increase the nickel production of the smelter or may be refined separately. The technical development of the SALT process will be described along with an economic summary. The SALT process has great potential to treat many Indonesian Nickel ores that are too low a grade for current technology.

  1. Progress in the Development of Lightweight Nickel Electrode for Nickel-Hydrogen Cell

    Science.gov (United States)

    Britton, Doris L.

    1999-01-01

    Development of a high specific energy battery is one of the objectives of the lightweight nickel-hydrogen (Ni-H2) program at the NASA Glenn Research Center. The approach has been to improve the nickel electrode by continuing combined in-house and contract efforts to develop a lighter weight electrode for the nickel-hydrogen cell. Small fiber diameter nickel plaques are used as conductive supports for the nickel hydroxide active material. These plaques are commercial products and have an advantage of increased surface area available for the deposition of active material. Initial tests include activation and capacity measurements at five different discharge levels, C/2, 1.0 C, 1.37 C, 2.0 C, and 2.74 C. The electrodes are life cycle tested using a half-cell configuration at 40 and 80% depths-of-discharge (DOD) in a low-Earth-orbit regime. The electrodes that pass the initial tests are life cycle-tested in a boiler plate nickel-hydrogen cell before flight weight design are built and tested.

  2. Zirconium modified nickel-copper alloy

    Science.gov (United States)

    Whittenberger, J. D. (Inventor)

    1977-01-01

    An improved material for use in a catalytic reactor which reduces nitrogen oxide from internal combustion engines is in the form of a zirconium-modified, precipitation-strengthened nickel-copper alloy. This material has a nominal composition of Ni-30 Cu-0.2 Zr and is characterized by improved high temperature mechanical properties.

  3. 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)

  4. 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.

  5. 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...

  6. Nickel electrodeposition from novel citrate bath

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A new type of electroplating bath suitable for nickel electrodeposition was developed. Trisodium citrate was used as a complexing agent and a buffer in the bath. The buffering capacity between trisodium citrate and boric acid were compared. The effects were investigated under different conditions of bath composition, current density, pH and temperature on the potentiodynamic cathodic polarization curves, cathodic current efficiency and throwing index, as well as the electrical conductivity of these baths. The optimum conditions for producing sound and satisfactory nickel deposits were: NiSO4·6H2O 350 g/L, NiC12·6H2O 45 g/L and Na3C6H5O7 30 g/L at pH=4 and 55 ℃. The surface morphology of the as-plated Ni deposit was examined by SEM. The results reveal that the nickel deposition obtained from the optimum conditions are composed of compact, non-porous fine grains covering the entire surface. X-ray analysis shows that nickel deposits obtained from the citrate bath have a fine crystal structure compared with deposits from the Watts bath.

  7. Nickel hydroxide modified electrodes for urea determination

    Directory of Open Access Journals (Sweden)

    Luiz Henrique Dall´Antonia

    2007-03-01

    Full Text Available Nickel hydroxide films were prepared by electrodeposition from a solution Ni(NO32 0,05 mol L ?¹ on ITO electrodes (Tin oxide doped with Indium on PET-like plastic film, applying a current of - 0,1 A cm ?² during different time intervals between 1800 and 7200 s. The electrochemical behavior of the nickel hydroxide electrode was investigated through a cyclic voltammogram, in NaOH 1,0 mol L ?¹, where it was observed two peaks in the profile in 0,410 and 0,280 V, corresponding to redox couple Ni(II/Ni(III. A sensor for urea presenting a satisfactory answer can be obtained when, after the deposit of the film of Ni(OH2 on the electrode of nickel, it is immersed in a solution of NaOH 1,0 mol L ?¹ and applying a potential of + 0,435 V, where the maximum of the anodic current occurs in the cyclic voltammogram. Analyzing the results it can be observed that, for a range of analite concentration between 5 to 50 m mol L ?¹, the behavior is linear and the sensibility found was of 20,3 mA cm?² (mol L?¹?¹, presenting reproducibility confirming the nickel hydroxide electrodes utilization for the determination of urea.

  8. 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...

  9. Castable nickel aluminide alloys for structural applications

    Science.gov (United States)

    Liu, Chain T.

    1992-01-01

    The specification discloses nickel aluminide alloys which include as a component from about 0.5 to about 4 at. % of one or more of the elements selected from the group consisting of molybdenum or niobium to substantially improve the mechanical properties of the alloys in the cast condition.

  10. Tests Of Advanced Nickel/Hydrogen Cells

    Science.gov (United States)

    Smithrick, John J.; Hall, Stephen W.

    1994-01-01

    Individual-pressure-vessel (IPV) nickel-hydrogen technology adanced with intention of improving cycle life and performance. One advancement to use 26 percent potassium hydroxide electrolyte to improve cycle life. Another to modify state-of-art cell design to eliminate identified failure modes.

  11. Suppression of pecan scab by nickel

    Science.gov (United States)

    The economic cost of scab, caused by Fusicladium effusum, can substantially limit the profitability of pecan [Carya illinoinensis (Wangenh.) K. Koch] cultivation in humid environments. Field and greenhouse experiments assessed the influence of nickel (Ni) on scab severity on fruit and foliage of Ni...

  12. Iron-induced nickel deficiency in pecan

    Science.gov (United States)

    Economic loss due to nickel (Ni) deficiency can occur in horticultural and agronomic crops. This study assesses impact of excessive iron (Fe) on expression of Ni deficiency in pecan [Carya illinoinensis (Wangenh.) K. Koch]. Field and greenhouse experiments found Ni deficiency to be inducible by ei...

  13. On the Solar Nickel and Oxygen Abundances

    Science.gov (United States)

    Scott, Pat; Asplund, Martin; Grevesse, Nicolas; Sauval, A. Jacques

    2009-02-01

    Determinations of the solar oxygen content relying on the neutral forbidden transition at 630 nm depend upon the nickel abundance, due to a Ni I blend. Here, we rederive the solar nickel abundance, using the same ab initio three-dimensional hydrodynamic model of the solar photosphere employed in the recent revision of the abundances of C, N, O, and other elements. Using 17 weak, unblended lines of Ni I together with the most accurate atomic and observational data available, we find log epsilonNi = 6.17 ± 0.02(statistical) ± 0.05(systematic), a downward shift of 0.06-0.08 dex relative to previous abundances based on one-dimensional model atmospheres. We investigate the implications of the new nickel abundance for studies of the solar oxygen abundance based on the [O I] 630 nm line in the quiet Sun. Furthermore, we demonstrate that the oxygen abundance implied by the recent sunspot spectropolarimetric study of Centeno & Socas-Navarro needs to be revised downward from log epsilonO = 8.86 ± 0.07 to 8.71 ± 0.10. This revision is based on the new nickel abundance, the application of the best available gf value for the 630 nm forbidden oxygen line, and a more transparent treatment of CO formation. Determinations of the solar oxygen content relying on forbidden lines now appear to converge around log epsilonO = 8.7.

  14. Delayed Nickel Decay in Gamma Ray Bursts

    CERN Document Server

    McLaughlin, G C

    2002-01-01

    Recently observed emission lines in the X-ray afterglow of gamma ray bursts suggest that iron group elements are either produced in the gamma ray burst, or are present nearby. If this material is the product of a thermonuclear burn, then such material would be expected to be rich in Nickel-56. If the nickel remains partially ionized, this prevents the electron capture reaction normally associated with the decay of Nickel-56, dramatically increasing the decay timescale. Here we examine the consequences of rapid ejection of a fraction of a solar mass of iron group material from the center of a collapsar/hypernova. The exact rate of decay then depends on the details of the ionization and therefore the ejection process. Future observations of iron, nickel and cobalt lines can be used to diagnose the origin of these elements and to better understand the astrophysical site of gamma ray bursts. In this model, the X-ray lines of these iron-group elements could be detected in suspected hypernovae that did not produce ...

  15. Replicative Intermediates of Human Papillomavirus Type 11 in Laryngeal Papillomas: Site of Replication Initiation and Direction of Replication

    Science.gov (United States)

    Auborn, K. J.; Little, R. D.; Platt, T. H. K.; Vaccariello, M. A.; Schildkraut, C. L.

    1994-07-01

    We have examined the structures of replication intermediates from the human papillomavirus type 11 genome in DNA extracted from papilloma lesions (laryngeal papillomas). The sites of replication initiation and termination utilized in vivo were mapped by using neutral/neutral and neutral/alkaline two-dimensional agarose gel electrophoresis methods. Initiation of replication was detected in or very close to the upstream regulatory region (URR; the noncoding, regulatory sequences upstream of the open reading frames in the papillomavirus genome). We also show that replication forks proceed bidirectionally from the origin and converge 180circ opposite the URR. These results demonstrate the feasibility of analysis of replication of viral genomes directly from infected tissue.

  16. A biokinetic model for nickel released from cardiovascular devices.

    Science.gov (United States)

    Saylor, David M; Adidharma, Lingga; Fisher, Jeffrey W; Brown, Ronald P

    2016-10-01

    Many alloys used in cardiovascular device applications contain high levels of nickel, which if released in sufficient quantities, can lead to adverse health effects. While nickel release from these devices is typically characterized through the use of in-vitro immersion tests, it is unclear if the rate at which nickel is released from a device during in-vitro testing is representative of the release rate following implantation in the body. To address this uncertainty, we have developed a novel biokinetic model that combines a traditional toxicokinetic compartment model with a physics-based model to estimate nickel release from an implanted device. This model links the rate of in-vitro nickel release from a cardiovascular device to serum nickel concentrations, an easily measured endpoint, to estimate the rate and extent of in-vivo nickel release from an implanted device. The model was initially parameterized using data in the literature on in-vitro nickel release from a nickel-containing alloy (nitinol) and baseline serum nickel levels in humans. The results of this first step were then used to validate specific components of the model. The remaining unknown quantities were fit using serum values reported in patients following implantation with nitinol atrial occluder devices. The model is not only consistent with levels of nickel in serum and urine of patients following treatment with the atrial occluders, but also the optimized parameters in the model were all physiologically plausible. The congruity of the model with available data suggests that it can provide a framework to interpret nickel biomonitoring data and use data from in-vitro nickel immersion tests to estimate in-vivo nickel release from implanted cardiovascular devices.

  17. In vitro dermal penetration of nickel nanoparticles.

    Science.gov (United States)

    Crosera, Matteo; Adami, Gianpiero; Mauro, Marcella; Bovenzi, Massimo; Baracchini, Elena; Larese Filon, Francesca

    2016-02-01

    Nickel nanoparticles (NiNPs) represent a new type of occupational exposure because, due to the small size/high surface, they can release more Ni ions compared to bulk material. It has been reported a case of a worker who developed sensitization while handling nickel nanopowder without precautions. Therefore there is the need to assess whether the skin absorption of NiNPs is higher compared to bulk nickel. Two independent in vitro experiments were performed using Franz diffusion cells. Eight cells for each experiment were fitted using intact and needle-abraded human skin. The donor phase was a suspension of NiNPs with mean size of 77.7 ± 24.1 nm in synthetic sweat. Ni permeated both types of skin, reaching higher levels up to two orders of magnitude in the damaged skin compared to intact skin (5.2 ± 2.0 vs 0.032 ± 0.010 μg cm(-2), p = 0.006) at 24 h. Total Ni amount into the skin was 29.2 ± 11.2 μg cm(-2) in damaged skin and 9.67 ± 2.70 μg cm(-2) in intact skin (mean and SD, p = 0.006). Skin abrasions lead to doubling the Ni amount in the epidermis and to an increase of ten times in the dermis. This study demonstrated that NiNPs applied on skin surface cause an increase of nickel content into the skin and a significant permeation flux through the skin, higher when a damaged skin protocol was used. Preventive measures are needed when NiNPs are produced and used due to their higher potential to enter in our body compared to bulk nickel.

  18. Environmentally Assisted Cracking of Nickel Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Rebak, R B

    2004-02-06

    Environmentally Assisted Cracking (EAC) is a general term that includes phenomena such as stress corrosion cracking (SCC), hydrogen embrittlement (HE), sulfide stress cracking (SSC), liquid metal embrittlement (LME), etc. EAC refers to a phenomenon by which a normally ductile metal looses its toughness (e.g. elongation to rupture) when it is subjected to mechanical stresses in presence of a specific corroding environment. For EAC to occur, three affecting factors must be present simultaneously. These include: (1) Mechanical tensile stresses, (2) A susceptible metal microstructure and (3) A specific aggressive environment. If any of these three factors is removed, EAC will not occur. That is, to mitigate the occurrence of EAC, engineers may for example eliminate residual stresses in a component or limit its application to certain chemicals (environment). The term environment not only includes chemical composition of the solution in contact with the component but also other variables such as temperature and applied potential. Nickel alloys are in general more resistant than stainless steels to EAC. For example, austenitic stainless steels (such as S30400) suffer SCC in presence of hot aqueous solutions containing chloride ions. Since chloride ions are ubiquitous in most industrial applications, the use of stressed stainless steels parts is seriously limited. On the other hand, nickel alloys (such as N10276) are practically immune to SCC in presence of hot chloride solutions and therefore an excellent alternative to replace the troubled stainless steels. Nonetheless, nickel alloys are not immune to other types of EAC. There are several environments (such as hot caustic and hot hydrofluoric acid) that may produce embrittlement in nickel alloys (Crum et al, 2000) (Table 1). The conditions where nickel alloys suffer EAC are highly specific and therefore avoidable by the proper design of the industrial components.

  19. Nickel accumulation and its effects on the survival rate of Spodoptera litura Fabricius under continuous nickel stress

    Institute of Scientific and Technical Information of China (English)

    SUN HongXia; SHU YingHua; TANG WenCheng; WANG Qi; ZHOU Qiang; ZHANG GuRen

    2007-01-01

    The artificial diets mixed with various concentrations of nickel were offered to the larvae of the phytophagous insect Spodoptera litura Fabricius for 3 generations. Nickel accumulations in the 6th instar larvae, pupae and newly emerged adults of the corresponding generations of S. litura were investigated by Inductively Coupled Plasma-Atomic Emission Spectrometer (ICP-AES), and the effects of nickel accumulations on the survival rate of S. litura were also evaluated by individual rearing. The results showed that nickel accumulated in the 6th instar larvae, pupae and adults of S. litura, and the accumulated nickel in all the tested developmental stages within a generation increased with the increase of the nickel doses in the treated diets and showed significant dose-dependent relationship with the nickel doses in the artificial diets. The results also indicated that the nickel accumulations in the 6th instar larvae, pupae, and newly emerged adults from the 3rd generation were higher than those from the 2nd generation, which were also higher than those from the 1st generation. Nickel concentrations in pupae and adults were significantly lower than those in larvae, which indicated that the excessive nickel might be excreted during metamorphosis. Furthermore, larval survival rate, pupation rate and eclosion rate of S. litura in the tested three generations all decreased with the increase of the nickel doses in the treated diets.

  20. Miniature lightweight x-ray optics (MiXO) for surface elemental composition mapping of asteroids and comets

    CERN Document Server

    Hong, Jaesub

    2016-01-01

    The compositions of diverse planetary bodies are of fundamental interest to planetary science, providing clues to the formation and evolutionary history of the target bodies and the Solar system as a whole. Utilizing the X-ray fluorescence unique to each atomic element, X-ray imaging spectroscopy is a powerful diagnostic tool of the chemical and mineralogical compositions of diverse planetary bodies. Until now the mass and volume of focusing X-ray optics have been too large for resource-limited in-situ missions, so near-target X-ray observations of planetary bodies have been limited to simple collimator-type X-ray instruments. We introduce a new Miniature lightweight Wolter-I focusing X-ray Optics (MiXO) using metal-ceramic hybrid X-ray mirrors based on electroformed nickel replication and plasma thermal spray processes. MiXO can enable compact, powerful imaging X-ray telescopes suitable for future planetary missions. We illustrate the need for focusing X-ray optics in observing relatively small planetary bod...

  1. Nickel allergy in patch-tested female hairdressers and assessment of nickel release from hairdressers' scissors and crochet hooks

    DEFF Research Database (Denmark)

    Thyssen, Jacob Pontoppidan; Milting, Kristina; Bregnhøj, Anne;

    2009-01-01

    BACKGROUND: Hand eczema as well as nickel contact allergy is prevalent among hairdressers. Recently, two female hairdressers were diagnosed with nickel contact allergy-related hand eczema following prolonged skin contact with scissors and crochet hooks used during work. OBJECTIVES: To determine...... the proportion of hairdressers' scissors and crochet hooks that released an excessive amount of nickel and to determine the prevalence of nickel allergy among patch-tested female hairdressers. MATERIALS: Random hairdressers' stores in Copenhagen were visited. The dimethylglyoxime (DMG) test was used to assess...... excessive nickel release. The prevalence of nickel allergy among female hairdressers from the database at Gentofte Hospital was compared with the prevalence of nickel allergy among other consecutively patch-tested dermatitis patients. RESULTS: DMG testing showed that 1 (0.5%; 95% CI = 0 - 2.0) of 200 pairs...

  2. Surface micro topography replication in injection moulding

    DEFF Research Database (Denmark)

    Arlø, Uffe Rolf

    of the mechanisms controlling topography replication. Surface micro topography replication in injection moulding depends on the main elements of  Process conditions  Plastic material  Mould topography In this work, the process conditions is the main factor considered, but the impact of plastic material...

  3. Replication and Robustness in Developmental Research

    Science.gov (United States)

    Duncan, Greg J.; Engel, Mimi; Claessens, Amy; Dowsett, Chantelle J.

    2014-01-01

    Replications and robustness checks are key elements of the scientific method and a staple in many disciplines. However, leading journals in developmental psychology rarely include explicit replications of prior research conducted by different investigators, and few require authors to establish in their articles or online appendices that their key…

  4. Completion of DNA replication in Escherichia coli.

    Science.gov (United States)

    Wendel, Brian M; Courcelle, Charmain T; Courcelle, Justin

    2014-11-18

    The mechanism by which cells recognize and complete replicated regions at their precise doubling point must be remarkably efficient, occurring thousands of times per cell division along the chromosomes of humans. However, this process remains poorly understood. Here we show that, in Escherichia coli, the completion of replication involves an enzymatic system that effectively counts pairs and limits cellular replication to its doubling point by allowing converging replication forks to transiently continue through the doubling point before the excess, over-replicated regions are incised, resected, and joined. Completion requires RecBCD and involves several proteins associated with repairing double-strand breaks including, ExoI, SbcDC, and RecG. However, unlike double-strand break repair, completion occurs independently of homologous recombination and RecA. In some bacterial viruses, the completion mechanism is specifically targeted for inactivation to allow over-replication to occur during lytic replication. The results suggest that a primary cause of genomic instabilities in many double-strand-break-repair mutants arises from an impaired ability to complete replication, independent from DNA damage.

  5. Replication and Robustness in Developmental Research

    Science.gov (United States)

    Duncan, Greg J.; Engel, Mimi; Claessens, Amy; Dowsett, Chantelle J.

    2014-01-01

    Replications and robustness checks are key elements of the scientific method and a staple in many disciplines. However, leading journals in developmental psychology rarely include explicit replications of prior research conducted by different investigators, and few require authors to establish in their articles or online appendices that their key…

  6. Using Replication Projects in Teaching Research Methods

    Science.gov (United States)

    Standing, Lionel G.; Grenier, Manuel; Lane, Erica A.; Roberts, Meigan S.; Sykes, Sarah J.

    2014-01-01

    It is suggested that replication projects may be valuable in teaching research methods, and also address the current need in psychology for more independent verification of published studies. Their use in an undergraduate methods course is described, involving student teams who performed direct replications of four well-known experiments, yielding…

  7. How frog embryos replicate their DNA reliably

    Science.gov (United States)

    Bechhoefer, John; Marshall, Brandon

    2007-03-01

    Frog embryos contain three billion base pairs of DNA. In early embryos (cycles 2-12), DNA replication is extremely rapid, about 20 min., and the entire cell cycle lasts only 25 min., meaning that mitosis (cell division) takes place in about 5 min. In this stripped-down cell cycle, there are no efficient checkpoints to prevent the cell from dividing before its DNA has finished replication - a disastrous scenario. Even worse, the many origins of replication are laid down stochastically and are also initiated stochastically throughout the replication process. Despite the very tight time constraints and despite the randomness introduced by origin stochasticity, replication is extremely reliable, with cell division failing no more than once in 10,000 tries. We discuss a recent model of DNA replication that is drawn from condensed-matter theories of 1d nucleation and growth. Using our model, we discuss different strategies of replication: should one initiate all origins as early as possible, or is it better to hold back and initiate some later on? Using concepts from extreme-value statistics, we derive the distribution of replication times given a particular scenario for the initiation of origins. We show that the experimentally observed initiation strategy for frog embryos meets the reliability constraint and is close to the one that requires the fewest resources of a cell.

  8. Mammalian RAD52 Functions in Break-Induced Replication Repair of Collapsed DNA Replication Forks

    DEFF Research Database (Denmark)

    Sotiriou, Sotirios K; Kamileri, Irene; Lugli, Natalia

    2016-01-01

    Human cancers are characterized by the presence of oncogene-induced DNA replication stress (DRS), making them dependent on repair pathways such as break-induced replication (BIR) for damaged DNA replication forks. To better understand BIR, we performed a targeted siRNA screen for genes whose depl...

  9. Rescue from replication stress during mitosis.

    Science.gov (United States)

    Fragkos, Michalis; Naim, Valeria

    2017-04-03

    Genomic instability is a hallmark of cancer and a common feature of human disorders, characterized by growth defects, neurodegeneration, cancer predisposition, and aging. Recent evidence has shown that DNA replication stress is a major driver of genomic instability and tumorigenesis. Cells can undergo mitosis with under-replicated DNA or unresolved DNA structures, and specific pathways are dedicated to resolving these structures during mitosis, suggesting that mitotic rescue from replication stress (MRRS) is a key process influencing genome stability and cellular homeostasis. Deregulation of MRRS following oncogene activation or loss-of-function of caretaker genes may be the cause of chromosomal aberrations that promote cancer initiation and progression. In this review, we discuss the causes and consequences of replication stress, focusing on its persistence in mitosis as well as the mechanisms and factors involved in its resolution, and the potential impact of incomplete replication or aberrant MRRS on tumorigenesis, aging and disease.

  10. A New Replication Norm for Psychology

    Directory of Open Access Journals (Sweden)

    Etienne P LeBel

    2015-10-01

    Full Text Available In recent years, there has been a growing concern regarding the replicability of findings in psychology, including a mounting number of prominent findings that have failed to replicate via high-powered independent replication attempts. In the face of this replicability “crisis of confidence”, several initiatives have been implemented to increase the reliability of empirical findings. In the current article, I propose a new replication norm that aims to further boost the dependability of findings in psychology. Paralleling the extant social norm that researchers should peer review about three times as many articles that they themselves publish per year, the new replication norm states that researchers should aim to independently replicate important findings in their own research areas in proportion to the number of original studies they themselves publish per year (e.g., a 4:1 original-to-replication studies ratio. I argue this simple approach could significantly advance our science by increasing the reliability and cumulative nature of our empirical knowledge base, accelerating our theoretical understanding of psychological phenomena, instilling a focus on quality rather than quantity, and by facilitating our transformation toward a research culture where executing and reporting independent direct replications is viewed as an ordinary part of the research process. To help promote the new norm, I delineate (1 how each of the major constituencies of the research process (i.e., funders, journals, professional societies, departments, and individual researchers can incentivize replications and promote the new norm and (2 any obstacles each constituency faces in supporting the new norm.

  11. 40 CFR 421.240 - Applicability: Description of the secondary nickel subcategory.

    Science.gov (United States)

    2010-07-01

    ... secondary nickel subcategory. 421.240 Section 421.240 Protection of Environment ENVIRONMENTAL PROTECTION... CATEGORY Secondary Nickel Subcategory § 421.240 Applicability: Description of the secondary nickel... nickel by secondary nickel facilities processing slag, spent acids, or scrap metal raw materials....

  12. 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.

  13. Ultrafast Mid-infrared Spectroscopy of the Charge- and Spin-Ordered Nickelate La1.75Sr0.25NiO4

    Directory of Open Access Journals (Sweden)

    Shen Z.-X.

    2013-03-01

    Full Text Available We present the first ultrafast mid-infrared study of charge and spin-ordered nickelates. A sub-picosecond modulation of the optical reflectivity is observed, indicating the filling and subsequent re-establishment of the pseudogap in the time-domain.

  14. Data from Investigating Variation in Replicability: A “Many Labs” Replication Project

    Directory of Open Access Journals (Sweden)

    Richard A. Klein

    2014-04-01

    Full Text Available This dataset is from the Many Labs Replication Project in which 13 effects were replicated across 36 samples and over 6,000 participants. Data from the replications are included, along with demographic variables about the participants and contextual information about the environment in which the replication was conducted. Data were collected in-lab and online through a standardized procedure administered via an online link. The dataset is stored on the Open Science Framework website. These data could be used to further investigate the results of the included 13 effects or to study replication and generalizability more broadly.

  15. On The Role of Wetting, Structure Width, and Flow Characteristics in Polymer Replication on Micro- and Nanoscale

    DEFF Research Database (Denmark)

    Rytka, Christian; Opara, Nadia; Andersen, Nis Korsgaard;

    2016-01-01

    The replication of functional polymeric micro- and nanostructures requires a deep understanding of material and process interrelations. In this investigation the dewetting potential of a polymer is proposed as a simple rationale for estimation of the replicability of functional micro- and nanostr......The replication of functional polymeric micro- and nanostructures requires a deep understanding of material and process interrelations. In this investigation the dewetting potential of a polymer is proposed as a simple rationale for estimation of the replicability of functional micro......- and nanostructures by injection molding. The dewetting potential of a polymer is determined by integrating the spreading coefficient over the range from melt temperature to no-flow temperature. From all polymers tested, the lowest dewetting potential is calculated for PP and the highest for polymethylmethacrylate....... The dewetting potential correlates well with the replicated height of four different structures covering both the micro- and the nanorange on two different surfaces (brass and fluorocarbon modified nickel) and polymers with different spreading coefficients. It is clearly shown that a lower dewetting potential...

  16. Replication forks reverse at high frequency upon replication stress in Physarum polycephalum.

    Science.gov (United States)

    Maric, Chrystelle; Bénard, Marianne

    2014-12-01

    The addition of hydroxyurea after the onset of S phase allows replication to start and permits the successive detecting of replication-dependent joint DNA molecules and chicken foot structures in the synchronous nuclei of Physarum polycephalum. We find evidence for a very high frequency of reversed replication forks upon replication stress. The formation of these reversed forks is dependent on the presence of joint DNA molecules, the impediment of the replication fork progression by hydroxyurea, and likely on the propensity of some replication origins to reinitiate replication to counteract the action of this compound. As hydroxyurea treatment enables us to successively detect the appearance of joint DNA molecules and then of reversed replication forks, we propose that chicken foot structures are formed both from the regression of hydroxyurea-frozen joint DNA molecules and from hydroxyurea-stalled replication forks. These experiments underscore the transient nature of replication fork regression, which becomes detectable due to the hydroxyurea-induced slowing down of replication fork progression.

  17. A quantitative model of DNA replication in Xenopus embryos: reliable replication despite stochasticity

    Science.gov (United States)

    Cheng-Hsin Yang, Scott; Bechhoefer, John

    2008-03-01

    DNA synthesis in Xenopus frog embryos initiates stochastically in time at many sites (origins) along the chromosome. Stochastic initiation implies fluctuations in the replication time and may lead to cell death if replication takes longer than the cell cycle time (˜ 25 min.). Surprisingly, although the typical replication time is about 20 min., in vivo experiments show that replication fails to complete only about 1 in 250 times. How is replication timing accurately controlled despite the stochasticity? Biologists have proposed two mechanisms: the first uses a regular spatial distribution of origins, while the second uses randomly located origins but increases their probability of initiation as the cell cycle proceeds. Here, we show that both mechanisms yield similar end-time distributions, implying that regular origin spacing is not needed for control of replication time. Moreover, we show that the experimentally inferred time-dependent initiation rate satisfies the observed low failure probability and nearly optimizes the use of replicative proteins.

  18. Targeting DNA Replication Stress for Cancer Therapy

    Science.gov (United States)

    Zhang, Jun; Dai, Qun; Park, Dongkyoo; Deng, Xingming

    2016-01-01

    The human cellular genome is under constant stress from extrinsic and intrinsic factors, which can lead to DNA damage and defective replication. In normal cells, DNA damage response (DDR) mediated by various checkpoints will either activate the DNA repair system or induce cellular apoptosis/senescence, therefore maintaining overall genomic integrity. Cancer cells, however, due to constitutive growth signaling and defective DDR, may exhibit “replication stress” —a phenomenon unique to cancer cells that is described as the perturbation of error-free DNA replication and slow-down of DNA synthesis. Although replication stress has been proven to induce genomic instability and tumorigenesis, recent studies have counterintuitively shown that enhancing replicative stress through further loosening of the remaining checkpoints in cancer cells to induce their catastrophic failure of proliferation may provide an alternative therapeutic approach. In this review, we discuss the rationale to enhance replicative stress in cancer cells, past approaches using traditional radiation and chemotherapy, and emerging approaches targeting the signaling cascades induced by DNA damage. We also summarize current clinical trials exploring these strategies and propose future research directions including the use of combination therapies, and the identification of potential new targets and biomarkers to track and predict treatment responses to targeting DNA replication stress. PMID:27548226

  19. Oncogene v-jun modulates DNA replication.

    Science.gov (United States)

    Wasylyk, C; Schneikert, J; Wasylyk, B

    1990-07-01

    Cell transformation leads to alterations in both transcription and DNA replication. Activation of transcription by the expression of a number of transforming oncogenes is mediated by the transcription factor AP1 (Herrlich & Ponta, 1989; Imler & Wasylyk, 1989). AP1 is a composite transcription factor, consisting of members of the jun and fos gene-families. c-jun and c-fos are progenitors of oncogenes, suggestion that an important transcriptional event in cell transformation is altered activity of AP1, which may arise either indirectly by oncogene expression or directly by structural modification of AP1. We report here that the v-jun oncogene and its progenitor c-jun, as fusion proteins with the lex-A-repressor DNA binding domain, can activate DNA replication from the Polyoma virus (Py) origin of replication, linked to the lex-A operator. The transcription-activation region of v-jun is required for activation of replication. When excess v-jun is expressed in the cell, replication is inhibited or 'squelched'. These results suggest that one consequence of deregulated jun activity could be altered DNA replication and that there are similarities in the way v-jun activates replication and transcription.

  20. Targeting DNA Replication Stress for Cancer Therapy

    Directory of Open Access Journals (Sweden)

    Jun Zhang

    2016-08-01

    Full Text Available The human cellular genome is under constant stress from extrinsic and intrinsic factors, which can lead to DNA damage and defective replication. In normal cells, DNA damage response (DDR mediated by various checkpoints will either activate the DNA repair system or induce cellular apoptosis/senescence, therefore maintaining overall genomic integrity. Cancer cells, however, due to constitutive growth signaling and defective DDR, may exhibit “replication stress” —a phenomenon unique to cancer cells that is described as the perturbation of error-free DNA replication and slow-down of DNA synthesis. Although replication stress has been proven to induce genomic instability and tumorigenesis, recent studies have counterintuitively shown that enhancing replicative stress through further loosening of the remaining checkpoints in cancer cells to induce their catastrophic failure of proliferation may provide an alternative therapeutic approach. In this review, we discuss the rationale to enhance replicative stress in cancer cells, past approaches using traditional radiation and chemotherapy, and emerging approaches targeting the signaling cascades induced by DNA damage. We also summarize current clinical trials exploring these strategies and propose future research directions including the use of combination therapies, and the identification of potential new targets and biomarkers to track and predict treatment responses to targeting DNA replication stress.

  1. Feasibility of Electrochemical Deposition of Nickel/Silicon Carbide Fibers Composites over Nickel Superalloys

    Science.gov (United States)

    Ambrosio, E. P.; Abdul Karim, M. R.; Pavese, M.; Biamino, S.; Badini, C.; Fino, P.

    2017-02-01

    Nickel superalloys are typical materials used for the hot parts of engines in aircraft and space vehicles. They are very important in this field as they offer high-temperature mechanical strength together with a good resistance to oxidation and corrosion. Due to high-temperature buckling phenomena, reinforcement of the nickel superalloy might be needed to increase stiffness. For this reason, it was thought to investigate the possibility of producing composite materials that might improve properties of the metal at high temperature. The composite material was produced by using electrochemical deposition method in which a composite with nickel matrix and long silicon carbide fibers was deposited over the nickel superalloy. The substrate was Inconel 718, and monofilament continuous silicon carbide fibers were chosen as reinforcement. Chemical compatibility was studied between Inconel 718 and the reinforcing fibers, with fibers both in an uncoated condition, and coated with carbon or carbon/titanium diboride. Both theoretical calculations and experiments were conducted, which suggested the use of a carbon coating over the fibers and a buffer layer of nickel to avoid unwanted reactions between the substrate and silicon carbide. Deposition was then performed, and this demonstrated the practical feasibility of the process. Yield strength was measured to detect the onset of interface debonding between the substrate and the composite layer.

  2. Recovery Of Nickel From Spent Nickel-Cadmium Batteries Using A Direct Reduction Process

    Directory of Open Access Journals (Sweden)

    Shin D.J.

    2015-06-01

    Full Text Available Most nickel is produced as Ferro-Nickel through a smelting process from Ni-bearing ore. However, these days, there have been some problems in nickel production due to exhaustion and the low-grade of Ni-bearing ore. Moreover, the smelting process results in a large amount of wastewater, slag and environmental risk. Therefore, in this research, spent Ni-Cd batteries were used as a base material instead of Ni-bearing ore for the recovery of Fe-Ni alloy through a direct reduction process. Spent Ni-Cd batteries contain 24wt% Ni, 18.5wt% Cd, 12.1% C and 27.5wt% polymers such as KOH. For pre-treatment, Cd was vaporized at 1024K. In order to evaluate the reduction conditions of nickel oxide and iron oxide, pre-treated spent Ni-Cd batteries were experimented on under various temperatures, gas-atmospheres and crucible materials. By a series of process, alloys containing 75 wt% Ni and 20 wt% Fe were produced. From the results, the reduction mechanism of nickel oxide and iron oxide were investigated.

  3. 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.

  4. 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.

  5. Influence of different etchants on the representation of microstructures in nickel alloys; Einfluss verschiedener Aetzmittel auf die Gefuegedarstellung in Nickellegierungen

    Energy Technology Data Exchange (ETDEWEB)

    Speicher, Magdalena; Scheck, Rudi; Maile, Karl [Stuttgart Univ. (Germany). Materialpruefungsanstalt

    2016-04-15

    This work presents a comparison of selected nickel alloys of the same condition which were treated by means of specifically chosen etching techniques. Microstructures on microscope images of wrought Alloy 617, a casting variant of Alloy 625, a polycrystalline casting alloy IN-738 LC, as well as of a monocrystalline superalloy CM 247 LC SX, respectively, are juxtaposed and evaluated. This approach allows for a comprehensive optical microscopy characterization of the characteristic microstructural features.

  6. A whole genome RNAi screen identifies replication stress response genes.

    Science.gov (United States)

    Kavanaugh, Gina; Ye, Fei; Mohni, Kareem N; Luzwick, Jessica W; Glick, Gloria; Cortez, David

    2015-11-01

    Proper DNA replication is critical to maintain genome stability. When the DNA replication machinery encounters obstacles to replication, replication forks stall and the replication stress response is activated. This response includes activation of cell cycle checkpoints, stabilization of the replication fork, and DNA damage repair and tolerance mechanisms. Defects in the replication stress response can result in alterations to the DNA sequence causing changes in protein function and expression, ultimately leading to disease states such as cancer. To identify additional genes that control the replication stress response, we performed a three-parameter, high content, whole genome siRNA screen measuring DNA replication before and after a challenge with replication stress as well as a marker of checkpoint kinase signalling. We identified over 200 replication stress response genes and subsequently analyzed how they influence cellular viability in response to replication stress. These data will serve as a useful resource for understanding the replication stress response.

  7. Study on the micro-replication of shark skin

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Direct replication of creatural scarfskins to form biomimetic surfaces with relatively vivid morphology is a new attempt of the bio-replicated forming technology at animal body. Taking shark skins as the replication templates, and the micro-embossing and micro-molding as the material forming methods, the micro-replicating technology of the outward morphology on shark skins was demonstrated. The preliminary analysis on replication precision indicates that the bio-replicated forming technology can replicate the outward morphology of the shark scales with good precision, which validates the application of the bio-replicated forming technology in the direct morphology replication of the firm creatural scarfskins.

  8. Replicated Data Management for Mobile Computing

    CERN Document Server

    Douglas, Terry

    2008-01-01

    Managing data in a mobile computing environment invariably involves caching or replication. In many cases, a mobile device has access only to data that is stored locally, and much of that data arrives via replication from other devices, PCs, and services. Given portable devices with limited resources, weak or intermittent connectivity, and security vulnerabilities, data replication serves to increase availability, reduce communication costs, foster sharing, and enhance survivability of critical information. Mobile systems have employed a variety of distributed architectures from client-server

  9. Optic glioma

    Science.gov (United States)

    Glioma - optic; Optic nerve glioma; Juvenile pilocytic astrocytoma; Brain cancer - optic glioma ... Optic gliomas are rare. The cause of optic gliomas is unknown. Most optic gliomas are slow-growing ...

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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)

  15. Techniques for Achieving Zero Stress in Thin Films of Iridium, Chromium, and Nickel

    Science.gov (United States)

    Broadway, David M.; O'Dell, Stephen L.; Ramsey, Brian D.; Weimer, Jeffrey

    2015-01-01

    We examine techniques for achieving zero intrinsic stress in thin films of iridium, chromium, and nickel deposited by magnetron sputter deposition. The intrinsic stress is further correlated to the microstructural features and physical properties such as surface roughness and optical density at a scale appropriate to soft X-ray wavelengths. The examination of the stress in these materials is motivated by efforts to advance the optical performance of light-weight X-ray space telescopes into the regime of sub-arcsecond resolution through various deposition techniques that rely on control of the film stress to values within 10-100 MPa. A characteristic feature of the intrinsic stress behavior in chromium and nickel is their sensitivity to the magnitude and sign of the intrinsic stress with argon gas pressure and deposition rate, including the existence of a critical argon process pressure that results in zero film stress which scales linearly with the atomic mass of the sputtered species. While the effect of stress reversal with argon pressure has been previously reported by Hoffman and others for nickel and chromium, we report this effect for iridium. In addition to stress reversal, we identify zero stress in the optical functioning iridium layer shortly after island coalescence for low process pressures at a film thickness of approximately 35nm. The measurement of the low values of stress during deposition was achieved with the aid of a sensitive in-situ instrument capable of a minimum detectable level of stress, assuming a 35nm thick film, in the range of 0.40-6.0 MPa for oriented crystalline silicon substrate thicknesses of 70-280 microns, respectively.

  16. Methane Tri-reforming over nickel catalysts

    OpenAIRE

    García Vargas, José Manuel

    2014-01-01

    The present work is part of a research program carried out in the Department of Chemical Engineering at the University of Castilla-La Mancha, focused in the preparation, characterization and evaluation of catalysts that can be applied in industrially relevant reactions. In this way, the PhD work reported here was aimed to study and improve nickel catalysts applied to the tri-reforming process, evaluating the role of support, precursor and promoter and optimizing the catalyst preparation. Furt...

  17. Magnetic crossover effect in Nickel nanowire arrays

    Energy Technology Data Exchange (ETDEWEB)

    Ghaddar, A. [Laboratoire de Magnetisme de Bretagne, CNRS-FRE 3117, C.S. 93837, 29238 Brest, Cedex (France); Gloaguen, F. [Laboratoire de Chimie, Electrochimie Moleculaire et Chimie Analytique, CNRS-UMR 6521, C. S. 93837 Brest Cedex 3 (France); Gieraltowski, J. [Laboratoire de Magnetisme de Bretagne, CNRS-FRE 3117, C.S. 93837, 29238 Brest, Cedex (France); Tannous, C., E-mail: tannous@univ-brest.f [Laboratoire de Magnetisme de Bretagne, CNRS-FRE 3117, C.S. 93837, 29238 Brest, Cedex (France)

    2011-05-01

    A crossover effect in the magnetic reversal mechanism within arrays of Nickel nanowires whose diameter varies from 15 to 100 nm is observed around 50 nm. Hysteresis loops and FMR measurements confirm that nanowire diameter controls effectively the nanowire easy axis as well as the magnetization reversal mechanism. This might be very interesting for spintronic devices based on current-induced domain motion such as non-volatile magnetic memory elements (MRAM) and low Ohmic loss devices.

  18. Laser Initiation of PETN containing Nickel Inclusions

    Science.gov (United States)

    Aduev, B. P.; Zvekov, A. A.; Nurmukhametov, D. R.; Nikitin, A. P.

    2017-01-01

    The spectral and kinetic characteristics of pentaerythritol tetranitrate (PETN) containing nickel nanoparticles glow initiated by laser pulses was studied with high temporal resolution. It was shown that glow which is chemiluminescence arises as a result of chemical reaction initiation. We suggest that the glow is concerned on excited nitrogen dioxide NO2 luminescence. The reaction propagation leads to the explosion in the microsecond time range that is accompanied by thermal glow of the reaction products with temperature T=4300 K.

  19. Recent breakthroughs in nickel base superalloys

    OpenAIRE

    Honnorat, Y.

    1993-01-01

    Meanwhile the considerable amount of results acquired since more than sixty years in the study of this class of materials, the pre-eminence of nickel base superalloys in the gas turbine engineering, which is a domain in constant evolution, drives the significant progresses accomplished along the five last years. The knowledge, each day more precisely known, of the working conditions of the parts, the continuous increase of the computer capacity and the progressive sophistication of the design...

  20. Effect of Catalyst on the Formation of Silica Coating on Nickel Substrate by Sol -Gel Processing

    Institute of Scientific and Technical Information of China (English)

    Ali Ghasemi; F.Ashrafizadeh; M.A.Golozar; Ali Ashrafi

    2004-01-01

    In this research work silica coating was produced on nickel substrates by a sol-gel process. In order to increase the rate of hydrolysis and to reduce the rate of polymerization several acid catalysts including nitric acid-hydrochloric acid,acetic acid, hydrochloric acid and nitric acid were add to silica sol. Conversely, in order to control the rate of hydrolysis and to increase the rate of polymerization, basic catalyst of ammonia and ammonia hydroxyl were introduced in to the solution.Nickel specimens of known surface roughness were chemically cleaned and prepared by dipping in the sols. In order to produce a suitable silica coating the drying and firing cycles were optimized on these substrates. The structure and uniformity of the coatings produced were examined by scanning electron microscopy. Coatings composition was determined using glow discharge optical spectroscopy and EDAX microanalysis. Experimental result showed that hydrochloric acid, acetic acid, ammonia and acetic acid - ammonia are suitable catalytic agents for silica coating formation on nickel type substrate.

  1. Characterization of nickel oxide films deposited at different substrate temperatures using spray pyrolysis

    Science.gov (United States)

    Kamal, H.; Elmaghraby, E. K.; Ali, S. A.; Abdel-Hady, K.

    2004-02-01

    Nickel oxide films have been deposited from nickel chloride solution by spray pyrolysis technique onto glass substrates at different substrate temperatures " Tsub". X-ray diffraction (XRD) analysis showed that, at low Tsub, amorphous films have been obtained, while at higher Tsub>275°C, crystalline NiO with preferential growth along (1 1 1) plane. From measurements of spectral transmittance and reflectance, and on the basis of Murmann's exact equations, the optical constants have been computed over the spectral range 300-2500 nm. Analysis of the spectral absorption confirmed direct and indirect transitions with values markedly affected by Tsub due to structure and off-stoichiometry changes of the formed films. The dark electrical resistivity drops with three orders of magnitude for films deposited at higher substrate temperature due to improvement in crystallinity. The results have been interpreted by assuming two-phase model. Infrared spectral reflectance showed presence of nickel chloride in films formed at Tsub⩽225°C, which is consistence with XRD findings and claiming incomplete pyrolytic reaction.

  2. QUASICONTINUUM SIMULATION OF NANOINDENTATION OF NICKEL FILM

    Institute of Scientific and Technical Information of China (English)

    Zeng Fanlin; Sun Yi

    2006-01-01

    A large-scale atom simulation of nanoindentation into a thin nickel film using the quasicontinuum method was performed. The initial stages of the plasticity deformation of nickel were studied. Several useful results were obtained as follows: (1) The response of the load versus indentation depth - on the load versus indentation depth curve, besides the straight parts corresponding to the elastic property of nickel, the sudden drop of the load occurred several times;(2) The phenomena of dislocation nucleation - the dislocation nucleation took place when the load descended, which makes it clear that dislocation nucleation causes the drop of the load; (3)The mechanism of the dislocation emission - the Peierls-Nabarro dislocation model and a powerful criterion were used to analyze the dislocation emission. And the computational value was in good agreement with the predict value; (4) The density of geometrically necessary dislocations.A simple model was used to obtain the density of geometrically necessary dislocations beneath the indenter. Furthermore, the influence of the boundary conditions on the simulation results was discussed.

  3. Mechanical electrodeposition of bright nanocrystalline nickel

    Institute of Scientific and Technical Information of China (English)

    ZHU ZengWei; ZHU Di; QU NingSong

    2008-01-01

    A new mechanical electrodeposition technology was proposed,and nanocrystal-line nickel deposit with bright and smooth surface was prepared in the bath without any additive agents.Unlike traditional methods,the novel technology employed dynamical hard particles to continuously polish the cathode surface and disturb the nearby solution during electrodepositing.Experimental results showed that the polishing effect of hard particles can effectively prevent the hydrogen bubbles and impurities from adhering on the deposit surface and avoid the production of pits,pinholes and nodules.Furthermore,comparing with the deposit prepared by tradi-tional methods,the one prepared by the novel technology was substantially refined with grain size ranging from 30 to 80 nm.Every diffraction peak's intensity of the deposit was reduced,the preferential orientation degree of (200) decreased and those of (111) and (220) increased.The microhardness notably increased.The magnetic properties were also changed with decreased saturation magnetization and increased coercive force.It was also found that variation of current density and cathode rotational speed could affect the structure and properties of the nickel deposits prepared by this technology.Key.words:electrodeposition,electroforming,hard particle,nanocrystalline,bright nickel deposits prepared by this technology.

  4. 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

    2014-01-01

    BACKGROUND: Several attempts to establish a model in mice that reflects nickel allergy in humans have been made. Most models use intradermal injection of nickel in combination with adjuvant to induce nickel allergy. However, such models poorly reflect induction of nickel allergy following long-la...

  5. 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

    From animal studies we know that oral administration of T-dependent antigens before sensitization effectively induces systemic immune unresponsiveness. Such 'oral tolerance' is persistent, dose-dependent, antigen-specific and presumably T suppressor cell-mediated. Oral tolerance induction could...... 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 frequency...

  6. A transcription and translation-coupled DNA replication system using rolling-circle replication.

    Science.gov (United States)

    Sakatani, Yoshihiro; Ichihashi, Norikazu; Kazuta, Yasuaki; Yomo, Tetsuya

    2015-05-27

    All living organisms have a genome replication system in which genomic DNA is replicated by a DNA polymerase translated from mRNA transcribed from the genome. The artificial reconstitution of this genome replication system is a great challenge in in vitro synthetic biology. In this study, we attempted to construct a transcription- and translation-coupled DNA replication (TTcDR) system using circular genomic DNA encoding phi29 DNA polymerase and a reconstituted transcription and translation system. In this system, phi29 DNA polymerase was translated from the genome and replicated the genome in a rolling-circle manner. When using a traditional translation system composition, almost no DNA replication was observed, because the tRNA and nucleoside triphosphates included in the translation system significantly inhibited DNA replication. To minimize these inhibitory effects, we optimized the composition of the TTcDR system and improved replication by approximately 100-fold. Using our system, genomic DNA was replicated up to 10 times in 12 hours at 30 °C. This system provides a step toward the in vitro construction of an artificial genome replication system, which is a prerequisite for the construction of an artificial cell.

  7. Using autonomous replication to physically and genetically define human origins of replication

    Energy Technology Data Exchange (ETDEWEB)

    Krysan, P.J.

    1993-01-01

    The author previously developed a system for studying autonomous replication in human cells involving the use of sequences from the Epstein-Barr virus (EBV) genome to provide extrachromosomal plasmids with a nuclear retention function. Using this system, it was demonstrated that large fragments of human genomic DNA could be isolated which replicate autonomously in human cells. In this study the DNA sequences which function as origins of replication in human cells are defined physically and genetically. These experiments demonstrated that replication initiates at multiple locations distributed throughout the plasmid. Another line of experiments addressed the DNA sequence requirements for autonomous replication in human cells. These experiments demonstrated that human DNA fragments have a higher replication activity than bacterial fragments do. It was also found, however, that the bacterial DNA sequence could support efficient replication if enough copies of it were present on the plasmid. These findings suggested that autonomous replication in human cells does not depend on extensive, specific DNA sequences. The autonomous replication system which the author has employed for these experiments utilizes a cis-acting sequence from the EBV origin and the trans-acting EBNA-1 protein to provide plasmids with a nuclear retention function. It was therefore relevant to verify that the autonomous replication of human DNA fragments did not depend on the replication activity associated with the EBV sequences utilized for nuclear retention. To accomplish this goal, the author demonstrated that plasmids carrying the EBV sequences and large fragments of human DNA could support long-term autonomous replication in hamster cells, which are not permissive for EBV replication.

  8. Mechanism of chromosomal DNA replication initiation and replication fork stabilization in eukaryotes.

    Science.gov (United States)

    Wu, LiHong; Liu, Yang; Kong, DaoChun

    2014-05-01

    Chromosomal DNA replication is one of the central biological events occurring inside cells. Due to its large size, the replication of genomic DNA in eukaryotes initiates at hundreds to tens of thousands of sites called DNA origins so that the replication could be completed in a limited time. Further, eukaryotic DNA replication is sophisticatedly regulated, and this regulation guarantees that each origin fires once per S phase and each segment of DNA gets duplication also once per cell cycle. The first step of replication initiation is the assembly of pre-replication complex (pre-RC). Since 1973, four proteins, Cdc6/Cdc18, MCM, ORC and Cdt1, have been extensively studied and proved to be pre-RC components. Recently, a novel pre-RC component called Sap1/Girdin was identified. Sap1/Girdin is required for loading Cdc18/Cdc6 to origins for pre-RC assembly in the fission yeast and human cells, respectively. At the transition of G1 to S phase, pre-RC is activated by the two kinases, cyclindependent kinase (CDK) and Dbf4-dependent kinase (DDK), and subsequently, RPA, primase-polα, PCNA, topoisomerase, Cdc45, polδ, and polɛ are recruited to DNA origins for creating two bi-directional replication forks and initiating DNA replication. As replication forks move along chromatin DNA, they frequently stall due to the presence of a great number of replication barriers on chromatin DNA, such as secondary DNA structures, protein/DNA complexes, DNA lesions, gene transcription. Stalled forks must require checkpoint regulation for their stabilization. Otherwise, stalled forks will collapse, which results in incomplete DNA replication and genomic instability. This short review gives a concise introduction regarding the current understanding of replication initiation and replication fork stabilization.

  9. Nickel powders recycled from invar scrap by magnesiothermic reduction.

    Science.gov (United States)

    Lee, Jin-Seok; Lee, Dong-Won; Lee, Hak-Sung; Yun, Jung-Yeul; Wang, Jei-Pil

    2014-12-01

    A study on the recovery of nickel from Fe-Ni alloy scrap was conducted using molten magnesium by dissolving only Ni component and then removing Mg using vacuum distillation method. The recovering faction of nickel higher than 99% was achieved at temperatures above 1,073 K and 99.5% of purity level of nickel was successfully obtained under vacuum degree of 10(-5) torr at temperatures above 1,273 K. The purity, phase, and recovery rate of nickel were examined by scanning electron microscopy, elemental analyser, and X-ray diffraction.

  10. Nickel clusters embedded in carbon nanotubes as high performance magnets

    Science.gov (United States)

    Shiozawa, Hidetsugu; Briones-Leon, Antonio; Domanov, Oleg; Zechner, Georg; Sato, Yuta; Suenaga, Kazu; Saito, Takeshi; Eisterer, Michael; Weschke, Eugen; Lang, Wolfgang; Peterlik, Herwig; Pichler, Thomas

    2015-10-01

    Ensembles of fcc nickel nanowires have been synthesized with defined mean sizes in the interior of single-wall carbon nanotubes. The method allows the intrinsic nature of single-domain magnets to emerge with large coercivity as their size becomes as small as the exchange length of nickel. By means of X-ray magnetic circular dichroism we probe electronic interactions at nickel-carbon interfaces where nickel exhibit no hysteresis and size-dependent spin magnetic moment. A manifestation of the interacting two subsystems on a bulk scale is traced in the nanotube’s magnetoresistance as explained within the framework of weak localization.

  11. 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.

  12. Ab initio coordination chemistry for nickel chelation motifs.

    Science.gov (United States)

    Sudan, R Jesu Jaya; Kumari, J Lesitha Jeeva; Sudandiradoss, C

    2015-01-01

    Chelation therapy is one of the most appreciated methods in the treatment of metal induced disease predisposition. Coordination chemistry provides a way to understand metal association in biological structures. In this work we have implemented coordination chemistry to study nickel coordination due to its high impact in industrial usage and thereby health consequences. This paper reports the analysis of nickel coordination from a large dataset of nickel bound structures and sequences. Coordination patterns predicted from the structures are reported in terms of donors, chelate length, coordination number, chelate geometry, structural fold and architecture. The analysis revealed histidine as the most favored residue in nickel coordination. The most common chelates identified were histidine based namely HHH, HDH, HEH and HH spaced at specific intervals. Though a maximum coordination number of 8 was observed, the presence of a single protein donor was noted to be mandatory in nickel coordination. The coordination pattern did not reveal any specific fold, nevertheless we report preferable residue spacing for specific structural architecture. In contrast, the analysis of nickel binding proteins from bacterial and archeal species revealed no common coordination patterns. Nickel binding sequence motifs were noted to be organism specific and protein class specific. As a result we identified about 13 signatures derived from 13 classes of nickel binding proteins. The specifications on nickel coordination presented in this paper will prove beneficial for developing better chelation strategies.

  13. Ab initio coordination chemistry for nickel chelation motifs.

    Directory of Open Access Journals (Sweden)

    R Jesu Jaya Sudan

    Full Text Available Chelation therapy is one of the most appreciated methods in the treatment of metal induced disease predisposition. Coordination chemistry provides a way to understand metal association in biological structures. In this work we have implemented coordination chemistry to study nickel coordination due to its high impact in industrial usage and thereby health consequences. This paper reports the analysis of nickel coordination from a large dataset of nickel bound structures and sequences. Coordination patterns predicted from the structures are reported in terms of donors, chelate length, coordination number, chelate geometry, structural fold and architecture. The analysis revealed histidine as the most favored residue in nickel coordination. The most common chelates identified were histidine based namely HHH, HDH, HEH and HH spaced at specific intervals. Though a maximum coordination number of 8 was observed, the presence of a single protein donor was noted to be mandatory in nickel coordination. The coordination pattern did not reveal any specific fold, nevertheless we report preferable residue spacing for specific structural architecture. In contrast, the analysis of nickel binding proteins from bacterial and archeal species revealed no common coordination patterns. Nickel binding sequence motifs were noted to be organism specific and protein class specific. As a result we identified about 13 signatures derived from 13 classes of nickel binding proteins. The specifications on nickel coordination presented in this paper will prove beneficial for developing better chelation strategies.

  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. Replicating chromatin: a tale of histones

    DEFF Research Database (Denmark)

    Groth, Anja

    2009-01-01

    Chromatin serves structural and functional roles crucial for genome stability and correct gene expression. This organization must be reproduced on daughter strands during replication to maintain proper overlay of epigenetic fabric onto genetic sequence. Nucleosomes constitute the structural...

  16. Control of chromosome replication in caulobacter crescentus.

    Science.gov (United States)

    Marczynski, Gregory T; Shapiro, Lucy

    2002-01-01

    Caulobacter crescentus permits detailed analysis of chromosome replication control during a developmental cell cycle. Its chromosome replication origin (Cori) may be prototypical of the large and diverse class of alpha-proteobacteria. Cori has features that both affiliate and distinguish it from the Escherichia coli chromosome replication origin. For example, requirements for DnaA protein and RNA transcription affiliate both origins. However, Cori is distinguished by several features, and especially by five binding sites for the CtrA response regulator protein. To selectively repress and limit chromosome replication, CtrA receives both protein degradation and protein phosphorylation signals. The signal mediators, proteases, response regulators, and kinases, as well as Cori DNA and the replisome, all show distinct patterns of temporal and spatial organization during cell cycle progression. Future studies should integrate our knowledge of biochemical activities at Cori with our emerging understanding of cytological dynamics in C. crescentus and other bacteria.

  17. LHCb Data Replication During SC3

    CERN Multimedia

    Smith, A

    2006-01-01

    LHCb's participation in LCG's Service Challenge 3 involves testing the bulk data transfer infrastructure developed to allow high bandwidth distribution of data across the grid in accordance with the computing model. To enable reliable bulk replication of data, LHCb's DIRAC system has been integrated with gLite's File Transfer Service middleware component to make use of dedicated network links between LHCb computing centres. DIRAC's Data Management tools previously allowed the replication, registration and deletion of files on the grid. For SC3 supplementary functionality has been added to allow bulk replication of data (using FTS) and efficient mass registration to the LFC replica catalog.Provisional performance results have shown that the system developed can meet the expected data replication rate required by the computing model in 2007. This paper details the experience and results of integration and utilisation of DIRAC with the SC3 transfer machinery.

  18. Initiation of Replication in Escherichia coli

    DEFF Research Database (Denmark)

    Frimodt-Møller, Jakob

    The circular chromosome of Escherichia coli is replicated by two replisomes assembled at the unique origin and moving in the opposite direction until they meet in the less well defined terminus. The key protein in initiation of replication, DnaA, facilitates the unwinding of double-stranded DNA...... to single-stranded DNA in oriC. Although DnaA is able to bind both ADP and ATP, DnaA is only active in initiation when bound to ATP. Although initiation of replication, and the regulation of this, is thoroughly investigated it is still not fully understood. The overall aim of the thesis was to investigate...... the regulation of initiation, the effect on the cell when regulation fails, and if regulation was interlinked to chromosomal organization. This thesis uncovers that there exists a subtle balance between chromosome replication and reactive oxygen species (ROS) inflicted DNA damage. Thus, failure in regulation...

  19. Surface Micro Topography Replication in Injection Moulding

    DEFF Research Database (Denmark)

    Arlø, Uffe Rolf; Hansen, Hans Nørgaard; Kjær, Erik Michael

    2005-01-01

    carried out with rough EDM (electrical discharge machining) mould surfaces, a PS grade, and by applying established three-dimensional topography parameters. Significant quantitative relationships between process parameters and topography parameters were established. It further appeared that replication...

  20. An efficient method to improve the proximity effect for electron beam optical disc mastering

    Science.gov (United States)

    Pan, C. T.; Chen, M. F.

    2005-04-01

    For the next-generation optical disc, electron beam mastering has been considered as a high-potential technique to fabricate a high-density optical disc. However, for electron beam mastering, the proximity effect caused by electron backscattering is an important problem. In this study, the influence of the proximity effect on the linewidth (full width at half magnitude, FWHM) and thickness of the residual resist is discussed. Some methods are presented to solve the proximity effect for optical disc mastering, i.e., by raising the electron beam voltage and depositing thin film material with low atomic number on a silicon substrate. In the study, thin film materials such as Al, Ni, SiO2, and Si3N4 are deposited on a silicon wafer to explore the proximity effect. The preliminary experimental results show that raising the electron beam voltage and depositing SiO2 or Si3N4 thin film on a silicon substrate can efficiently solve this problem. Later, the resist with a nano-pattern is transferred into a metal Ni-Co (nickel-cobalt) mould by electroplating. The technique of the Ni-Co electroplating process with hardness at least Vicker hardness (Hv) 650 and residual stress below 1.5 kg mm-2 is developed. Then, with the Ni-Co mould, a modified LIGA process is applied to produce a high-density optical disc. The Ni-Co mould serves as the master for the hot embossing process to replicate the nano-pattern onto the PMMA sheet. Since the feature size is down to the nanometre range, the study presents an innovative demoulding mechanism to demould the master from the PMMA sheet without damaging the nanometre patterns.