Sample records for hafnium hydroxides

  1. Simultaneous determination of tantalum and hafnium in silicates by neutron activation analysis

    USGS Publications Warehouse

    Greenland, L.P.

    1968-01-01

    A neutron activation procedure suitable for the routine determination of tantalum and hafnium in silicates is described. The irradiated sample is fused with sodium peroxide and leached, and the insoluble hydroxides are dissolved in dilute hydrofluoric acid-hydrochloric acid. After LaF3 and AgCl scavenges, tantalum and hafnium are separated by anion exchange. Tantalum is obtained radiochemically pure; 233Pa and 95Zr contaminants in the hafnium fraction are resolved by ??-ray spectrometry. The chemical yield of the procedure is detemined after counting by re-irradiation. Values for the 8 U.S. Geological Survey standard rocks are reported. ?? 1968.

  2. Hafnium radioisotope recovery from irradiated tantalum

    DOEpatents

    Taylor, Wayne A.; Jamriska, David J.

    2001-01-01

    Hafnium is recovered from irradiated tantalum by: (a) contacting the irradiated tantalum with at least one acid to obtain a solution of dissolved tantalum; (b) combining an aqueous solution of a calcium compound with the solution of dissolved tantalum to obtain a third combined solution; (c) precipitating hafnium, lanthanide, and insoluble calcium complexes from the third combined solution to obtain a first precipitate; (d) contacting the first precipitate of hafnium, lanthanide and calcium complexes with at least one fluoride ion complexing agent to form a fourth solution; (e) selectively adsorbing lanthanides and calcium from the fourth solution by cationic exchange; (f) separating fluoride ion complexing agent product from hafnium in the fourth solution by adding an aqueous solution of ferric chloride to obtain a second precipitate containing the hafnium and iron; (g) dissolving the second precipitate containing the hafnium and iron in acid to obtain an acid solution of hafnium and iron; (h) selectively adsorbing the iron from the acid solution of hafnium and iron by anionic exchange; (i) drying the ion exchanged hafnium solution to obtain hafnium isotopes. Additionally, if needed to remove residue remaining after the product is dried, dissolution in acid followed by cation exchange, then anion exchange, is performed.

  3. Ablation Resistant Zirconium and Hafnium Ceramics

    NASA Technical Reports Server (NTRS)

    Bull, Jeffrey (Inventor); White, Michael J. (Inventor); Kaufman, Larry (Inventor)

    1998-01-01

    High temperature ablation resistant ceramic composites have been made. These ceramics are composites of zirconium diboride and zirconium carbide with silicon carbide, hafnium diboride and hafnium carbide with silicon carbide and ceramic composites which contain mixed diborides and/or carbides of zirconium and hafnium. along with silicon carbide.

  4. Hafnium isotope stratigraphy of ferromanganese crusts

    PubMed

    Lee; Halliday; Hein; Burton; Christensen; Gunther

    1999-08-13

    A Cenozoic record of hafnium isotopic compositions of central Pacific deep water has been obtained from two ferromanganese crusts. The crusts are separated by more than 3000 kilometers but display similar secular variations. Significant fluctuations in hafnium isotopic composition occurred in the Eocene and Oligocene, possibly related to direct advection from the Indian and Atlantic oceans. Hafnium isotopic compositions have remained approximately uniform for the past 20 million years, probably reflecting increased isolation of the central Pacific. The mechanisms responsible for the increase in (87)Sr/(86)Sr in seawater through the Cenozoic apparently had no effect on central Pacific deep-water hafnium.

  5. SEPARATION OF HAFNIUM FROM ZIRCONIUM

    DOEpatents

    Overholser, L.B.; Barton, C.J. Sr.; Ramsey, J.W.

    1960-05-31

    The separation of hafnium impurities from zirconium can be accomplished by means of organic solvent extraction. The hafnium-containing zirconium feed material is dissolved in an aqueous chloride solution and the resulting solution is contacted with an organic hexone phase, with at least one of the phases containing thiocyanate. The hafnium is extracted into the organic phase while zirconium remains in the aqueous phase. Further recovery of zirconium is effected by stripping the onganic phase with a hydrochloric acid solution and commingling the resulting strip solution with the aqueous feed solution. Hexone is recovered and recycled by means of scrubbing the onganic phase with a sulfuric acid solution to remove the hafnium, and thiocyanate is recovered and recycled by means of neutralizing the effluent streams to obtain ammonium thiocyanate.

  6. Zirconium and hafnium

    USGS Publications Warehouse

    Jones, James V.; Piatak, Nadine M.; Bedinger, George M.; Schulz, Klaus J.; DeYoung,, John H.; Seal, Robert R.; Bradley, Dwight C.

    2017-12-19

    Zirconium and hafnium are corrosion-resistant metals that are widely used in the chemical and nuclear industries. Most zirconium is consumed in the form of the main ore mineral zircon (ZrSiO4, or as zirconium oxide or other zirconium chemicals. Zirconium and hafnium are both refractory lithophile elements that have nearly identical charge, ionic radii, and ionic potentials. As a result, their geochemical behavior is generally similar. Both elements are classified as incompatible because they have physical and crystallochemical properties that exclude them from the crystal lattices of most rock-forming minerals. Zircon and another, less common, ore mineral, baddeleyite (ZrO2), form primarily as accessory minerals in igneous rocks. The presence and abundance of these ore minerals in igneous rocks are largely controlled by the element concentrations in the magma source and by the processes of melt generation and evolution. The world’s largest primary deposits of zirconium and hafnium are associated with alkaline igneous rocks, and, in one locality on the Kola Peninsula of Murmanskaya Oblast, Russia, baddeleyite is recovered as a byproduct of apatite and magnetite mining. Otherwise, there are few primary igneous deposits of zirconium- and hafnium-bearing minerals with economic value at present. The main ore deposits worldwide are heavy-mineral sands produced by the weathering and erosion of preexisting rocks and the concentration of zircon and other economically important heavy minerals, such as ilmenite and rutile (for titanium), chromite (for chromium), and monazite (for rare-earth elements) in sedimentary systems, particularly in coastal environments. In coastal deposits, heavy-mineral enrichment occurs where sediment is repeatedly reworked by wind, waves, currents, and tidal processes. The resulting heavy-mineral-sand deposits, called placers or paleoplacers, preferentially form at relatively low latitudes on passive continental margins and supply 100 percent of

  7. Hafnium Oxide Film Etching Using Hydrogen Chloride Gas

    NASA Astrophysics Data System (ADS)

    Habuka, Hitoshi; Yamaji, Masahiko; Kobori, Yoshitsugu; Horii, Sadayoshi; Kunii, Yasuo

    2009-12-01

    Hydrogen chloride gas removes the hafnium oxide film formed by atomic layer deposition at the etch rate of about 1 nm/min. A 100 nm-thick hafnium oxide film was perfectly etched off at 1173 K for 60 min by 100% hydrogen chloride gas at 100 sccm. A weight decrease in the hafnium oxide film was observed at temperatures higher than ca. 600 K, which corresponds to the sublimation point of hafnium tetrachloride. The etching by-product is considered to be hafnium tetrachloride. The etching technique developed in this study is expected to be applicable to various processes, such as the cleaning of a hafnium oxide film deposition reactor.

  8. Studies on Optical and Electrical Properties of Hafnium Oxide Nanoparticles

    NASA Astrophysics Data System (ADS)

    Jayaraman, Venkatachalam; Sagadevan, Suresh; Sudhakar, Rajesh

    2017-07-01

    In this paper, the synthesis and physico-chemical properties of hafnium oxide nanoparticles (HfO2 NPs) are analyzed and reported. The synthesis was carried out by the precipitation route by using hafnium tetrachloride (HfCl4) as precursor material with potassium hydroxide (KOH) dissolved in Millipore water. In the precipitation technique, the chemical reaction is comparatively simple, low-cost and non-toxic compared to other synthetic methods. The synthesized HfO2 NPs were characterized by using powder x-ray diffraction (PXRD), ultraviolet-visible (UV-Vis) spectroscopy, Raman analysis, and high-resolution transmission electron microscopy (HRTEM). The monoclinic structure of the HfO2 NPs was resolved utilizing x-ray diffraction (XRD). The optical properties were studied from the UV-Vis absorption spectrum. The optical band gap of the HfO2NPs was observed to be 5.1 eV. The Raman spectrum shows the presence of HfO2 NPs. The HRTEM image showed that the HfO2 NPs were of spherical shape with an average particle size of around 28 nm. The energy-dispersive x-ray spectroscopy (EDS) spectrum obviously demonstrated the presence of HfO2 NPs. Analysis and studies on the dielectric properties of the HfO2 NPs such as the dielectric constant, the dielectric loss, and alternating current (AC) conductivity were carried out at varying frequencies and temperatures.

  9. SEPARATING HAFNIUM FROM ZIRCONIUM

    DOEpatents

    Lister, B.A.J.; Duncan, J.F.

    1956-08-21

    A dilute aqueous solution of zirconyl chloride which is 1N to 2N in HCl is passed through a column of a cation exchange resin in acid form thereby absorbing both zirconium and associated hafnium impurity in the mesin. The cation exchange material with the absorbate is then eluted with aqueous sulfuric acid of a O.8N to 1.2N strength. The first portion of the eluate contains the zirconium substantially free of hafnium.

  10. Formulation and method for preparing gels comprising hydrous hafnium oxide

    DOEpatents

    Collins, Jack L; Hunt, Rodney D; Montgomery, Frederick C

    2013-08-06

    Formulations useful for preparing hydrous hafnium oxide gels contain a metal salt including hafnium, an acid, an organic base, and a complexing agent. Methods for preparing gels containing hydrous hafnium oxide include heating a formulation to a temperature sufficient to induce gel formation, where the formulation contains a metal salt including hafnium, an acid, an organic base, and a complexing agent.

  11. Silver-hafnium braze alloy

    DOEpatents

    Stephens, Jr., John J.; Hosking, F. Michael; Yost, Frederick G.

    2003-12-16

    A binary allow braze composition has been prepared and used in a bonded article of ceramic-ceramic and ceramic-metal materials. The braze composition comprises greater than approximately 95 wt % silver, greater than approximately 2 wt % hafnium and less than approximately 4.1 wt % hafnium, and less than approximately 0.2 wt % trace elements. The binary braze alloy is used to join a ceramic material to another ceramic material or a ceramic material, such as alumina, quartz, aluminum nitride, silicon nitride, silicon carbide, and mullite, to a metal material, such as iron-based metals, cobalt-based metals, nickel-based metals, molybdenum-based metals, tungsten-based metals, niobium-based metals, and tantalum-based metals. A hermetic bonded article is obtained with a strength greater than 10,000 psi.

  12. Hafnium-Based Contrast Agents for X-ray Computed Tomography.

    PubMed

    Berger, Markus; Bauser, Marcus; Frenzel, Thomas; Hilger, Christoph Stephan; Jost, Gregor; Lauria, Silvia; Morgenstern, Bernd; Neis, Christian; Pietsch, Hubertus; Sülzle, Detlev; Hegetschweiler, Kaspar

    2017-05-15

    Heavy-metal-based contrast agents (CAs) offer enhanced X-ray absorption for X-ray computed tomography (CT) compared to the currently used iodinated CAs. We report the discovery of new lanthanide and hafnium azainositol complexes and their optimization with respect to high water solubility and stability. Our efforts culminated in the synthesis of BAY-576, an uncharged hafnium complex with 3:2 stoichiometry and broken complex symmetry. The superior properties of this asymmetrically substituted hafnium CA were demonstrated by a CT angiography study in rabbits that revealed excellent signal contrast enhancement.

  13. 40 CFR 471.90 - Applicability; description of the zirconium-hafnium forming subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... zirconium-hafnium forming subcategory. 471.90 Section 471.90 Protection of Environment ENVIRONMENTAL... POINT SOURCE CATEGORY Zirconium-Hafnium Forming Subcategory § 471.90 Applicability; description of the zirconium-hafnium forming subcategory. This subpart applies to discharges of pollutants to waters of the...

  14. 40 CFR 421.330 - Applicability: Description of the primary zirconium and hafnium subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... primary zirconium and hafnium subcategory. 421.330 Section 421.330 Protection of Environment ENVIRONMENTAL... CATEGORY Primary Zirconium and Hafnium Subcategory § 421.330 Applicability: Description of the primary zirconium and hafnium subcategory. The provisions of this subpart are applicable to discharges resulting...

  15. Hafnium silicate and hafnium silicon oxynitride gate dielectrics for strained Si_xGe_1-x: Interface stability

    NASA Astrophysics Data System (ADS)

    Addepalli, Swarna; Sivasubramani, Prasanna; El-Bouanani, Mohamed; Kim, Moon; Gnade, Bruce; Wallace, Robert

    2003-03-01

    Strained Si_xGe_1-x layers have gained considerable attention due to hole mobility enhancement, and ease of integration with Si-based CMOS technology. The deposition of stable high-κ dielectrics [1] such as hafnium silicate and hafnium silicon oxynitride in direct contact with SiGe would simultaneously improve the capacitance of the gate stack and lower the leakage current for high performance SiGe devices. However, the oxidation of the Si_xGe_1-x substrate either during dielectric deposition or post-deposition processing would degrade device performance due to the thermodynamic instability of germanium oxide [2,3]. Results from XPS, HR-TEM, and C-V, and I-V analyses after various annealing treatments will be presented for hafnium silicate and hafnium silicon oxynitride films deposited on strained Si_xGe_1-x(100), and correlated with dielectric-Si_xGe_1-x(100) interface stability. Implications to the introduction of these oxides as viable gate dielectric candidates for SiGe-based CMOS technology will be discussed. This work is supported by DARPA through SPAWAR Grant No. N66001-00-1-8928, and the Texas Advanced Technology Program. References: [1] G. D. Wilk, R. M. Wallace and J. M. Anthony, Journal of Applied Physics, 89, 5243 (2001) [2] W. S. Liu, J .S. Chen, M.-A. Nicolet, V. Arbet-Engels, K. L. Wang, Journal of Applied Physics, 72, 4444 (1992), and, Applied Physics Letters, 62, 3321 (1993) [3] W. S. Liu, M. -A. Nicolet, H. -H. Park, B. -H. Koak, J. -W. Lee, Journal of Applied Physics, 78, 2631 (1995)

  16. A simple spectrophotometric method for determination of zirconium or hafnium in selected molybdenum-base alloys

    NASA Technical Reports Server (NTRS)

    Dupraw, W. A.

    1972-01-01

    A simple analytical procedure is described for accurately and precisely determining the zirconium or hafnium content of molybdenum-base alloys. The procedure is based on the reaction of the reagent Arsenazo III with zirconium or hafnium in strong hydrochloric acid solution. The colored complexes of zirconium or hafnium are formed in the presence of molybdenum. Titanium or rhenium in the alloy have no adverse effect on the zirconium or hafnium complex at the following levels in the selected aliquot: Mo, 10 mg; Re, 10 mg; Ti, 1 mg. The spectrophotometric measurement of the zirconium or hafnium complex is accomplished without prior separation with a relative standard deviation of 1.3 to 2.7 percent.

  17. Hafnium(IV) chloride complexes with chelating β-ketiminate ligands: Synthesis, spectroscopic characterization and volatility study

    NASA Astrophysics Data System (ADS)

    Patil, Siddappa A.; Medina, Phillip A.; Antic, Aleks; Ziller, Joseph W.; Vohs, Jason K.; Fahlman, Bradley D.

    2015-09-01

    The synthesis and characterization of four new β-ketiminate hafnium(IV) chloride complexes dichloro-bis[4-(phenylamido)pent-3-en-2-one]-hafnium (4a), dichloro-bis[4-(4-methylphenylamido)pent-3-en-2-one]-hafnium (4b), dichloro-bis[4-(4-methoxyphenylamido)pent-3-en-2-one]-hafnium (4c), and dichloro-bis[4-(4-chlorophenylamido)pent-3-en-2-one]-hafnium (4d) are reported. All the complexes (4a-d) were characterized by spectroscopic methods (1H NMR, 13C NMR, IR), and elemental analysis while the compound 4c was further examined by single-crystal X-ray diffraction, revealing that the complex is monomer with the hafnium center in octahedral coordination environment and oxygens of the chelating N-O ligands are trans to each other and the chloride ligands are in a cis arrangement. Volatile trends are established for four new β-ketiminate hafnium(IV) chloride complexes (4a-d). Sublimation enthalpies (ΔHsub) were calculated from thermogravimetric analysis (TGA) data, which show that, the dependence of ΔHsub on the molecular weight (4a-c) and inductive effects from chlorine (4d).

  18. Hafnium transistor process design for neural interfacing.

    PubMed

    Parent, David W; Basham, Eric J

    2009-01-01

    A design methodology is presented that uses 1-D process simulations of Metal Insulator Semiconductor (MIS) structures to design the threshold voltage of hafnium oxide based transistors used for neural recording. The methodology is comprised of 1-D analytical equations for threshold voltage specification, and doping profiles, and 1-D MIS Technical Computer Aided Design (TCAD) to design a process to implement a specific threshold voltage, which minimized simulation time. The process was then verified with a 2-D process/electrical TCAD simulation. Hafnium oxide films (HfO) were grown and characterized for dielectric constant and fixed oxide charge for various annealing temperatures, two important design variables in threshold voltage design.

  19. Thermochemistry of amorphous and crystalline zirconium and hafnium silicates.

    NASA Astrophysics Data System (ADS)

    Ushakov, S.; Brown, C. E.; Navrotsky, Alexandra; Boatner, L. A.; Demkov, A. A.; Wang, C.; Nguyen, B.-Y.

    2003-03-01

    Calorimetric investigation of amorphous and crystalline zirconium and hafnium silicates was performed as part of a research program on thermochemistry of alternative gate dielectrics. Amorphous hafnium and zirconium silicates with varying SiO2 content were synthesized by a sol-gel process. Crystalline zirconium and hafnium silicates (zircon and hafnon) were synthesized by solid state reaction at 1450 °C from amorphous gels and grown as single crystals from flux. High temperature oxide melt solution calorimetry in lead borate (2PbO.B2O3) solvent at 800 oC was used to measure drop solution enthalpies for amorphous and crystalline zirconium and hafnium silicates and corresponding oxides. Applying appropriate thermochemical cycles, formation enthalpy of crystalline ZrSiO4 (zircon) from binary oxides (baddeleite and quartz) at 298 K was calculated as -23 +/-2 kJ/mol and enthalpy difference between amorphous and crystalline zirconium silicate (vitrification enthalpy) was found to be 61 +/-3 kJ/mol. Crystallization onset temperatures of amorphous zirconium and hafnium silicates, as measured by differential scanning calorimetry (DSC), increased with silica content. The resulting crystalline phases, as characterized by X-ray diffraction (XRD), were tetragonal HfO2 and ZrO2. Critical crystallite size for tetragonal to monoclinic transformation of HfO2 in the gel was estimated as 6 +/-2 nm from XRD data Crystallization enthalpies per mole of hafnia and zirconia in gels decrease slightly together with crystallite size with increasing silica content, for example from -22 to -15 +/-1 kJ per mol of HfO2 crystallized at 740 and 1006 °C from silicates with 10 and 70 mol Applications of thermal analyses and solution calorimetry techniques together with first-principles density functional calculations to estimate interface and surface energies are discussed.

  20. Aluminum Hydroxide and Magnesium Hydroxide

    MedlinePlus

    Aluminum Hydroxide, Magnesium Hydroxide are antacids used together to relieve heartburn, acid indigestion, and upset stomach. They ... They combine with stomach acid and neutralize it. Aluminum Hydroxide, Magnesium Hydroxide are available without a prescription. ...

  1. The Hot-Pressing of Hafnium Carbide (Melting Point, 7030 F)

    NASA Technical Reports Server (NTRS)

    Sanders, William A.; Grisaffe, Salvatore J.

    1960-01-01

    An investigation was undertaken to determine the effects of the hot-pressing variables (temperature, pressure, and time) on the density and grain size of hafnium carbide disks. The purpose was to provide information necessary for the production of high-density test shapes for the determination of physical and mechanical properties. Hot-pressing of -325 mesh hafnium carbide powder was accomplished with a hydraulic press and an inductively heated graphite die assembly. The ranges investigated for each variable were as follows: temperature, 3500 to 4870 F; pressure, 1000 to 6030 pounds per square inch; and time, 5 to 60 minutes. Hafnium carbide bodies of approximately 98 percent theoretical density can be produced under the following minimal conditions: 4230 F, 3500 pounds per square inch, and 15 minutes. Further increases in temperature and time resulted only in greater grain size.

  2. Zirconium and hafnium in the southeastern Atlantic States

    USGS Publications Warehouse

    Mertie, J.B.

    1958-01-01

    The principal source of zirconium and hafnium is zircon, though a minor source is baddeleyite, mined only in Brazil. Zircon is an accessory mineral in igneous, metamorphic, and sedimentary rocks, but rarely occurs in hardrock in minable quantities. The principal sources of zircon are therefore alluvial deposits, which are mined in many countries of five continents. The principal commercial deposits in the United States are in Florida, though others exist elsewhere in the southeastern Coastal Plain. The evidence indicates that conditions for the accumulation of workable deposits of heavy minerals were more favorable during the interglacial stages of the Pleistocene epoch than during Recent time. Therefore detrital ores of large volume and high tenor are more likely to be found in the terrace deposits than along the present beaches. Other concentrations of heavy minerals, however, are possible at favored sites close to the Fall Line where the Tuscaloosa formation rests upon the crystalline rocks of the Piedmont province. A score of heavy and semiheavy minerals occur in the detrital deposits of Florida, but the principal salable minerals are ilmenite, leucoxene, rutile, and zircon, though monazite and staurolite are saved at some mining plants. Commercial deposits of heavy minerals are generally required to have a tenor of 4 percent, though ores with a lower tenor can be mined at a profit if the content of monazite is notably high. The percentages of zircon in the concentrates ranges from 10 to 16 percent, and in eastern Florida from 13 to 15 percent. Thus the tenor in zircon of the ore-bearing sands ranges from 0.4 to 0.6 percent. The content of hafnium in zircon is immaterial for many uses, but for some purposes very high or very low tenors in hafnium are required. Alluvial zircon cannot be separated into such varieties, which, if needed, must be obtained from sources in bedrock. It thus becomes necessary to determine the Hf : Zr ratios in zircon from many kinds of

  3. Separation of Zirconium and Hafnium: A Review

    NASA Astrophysics Data System (ADS)

    Xu, L.; Xiao, Y.; van Sandwijk, A.; Xu, Q.; Yang, Y.

    Zirconium is an ideal material for nuclear reactors due to its low absorption cross-section for thermal neutrons, whereas the typically contained hafnium with strong neutron-absorption is very harmful for zirconium. This paper provides an overview of the processes for separating hafnium from zirconium. The separation processes are roughly classified into hydro- and pyrometallurgical routes. The current dominant zirconium production route involves pyrometallurgical ore cracking, multi-step hydrometallurgical liquid-liquid extraction for hafnium removal and the reduction of zirconium tetrachloride to the pure metal by the Kroll process. The lengthy hydrometallurgical Zr-Hf separation operations leads to high production cost, intensive labour and heavy environmental burden. Using a compact pyrometallurgical separation method can simplify the whole production flowsheet with a higher process efficiency. The known separation methods are discussed based on the following reaction features: redox characteristics, volatility, electrochemical properties and molten salt extraction. The commercially operating extractive distillation process is a significant advance in Zr-Hf separation technology but it suffers from high process maintenance cost. The recently developed new process based on molten salt-metal equilibrium for Zr-Hf separation shows a great potential for industrial application, which is compact for nuclear grade zirconium production starting from crude ore. In the present paper, the available separation technologies are compared. The advantages and disadvantages as well as future directions of research and development for nuclear grade zirconium production are discussed.

  4. High P-T phase transitions and P-V-T equation of state of hafnium

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hrubiak, Rostislav; Drozd, Vadym; Karbasi, Ali

    2016-07-29

    We measured the volume of hafnium at several pressures up to 67 GPa and at temperatures between 300 to 780 K using a resistively heated diamond anvil cell with synchrotron x-ray diffraction at the Advanced Photon Source. The measured data allows us to determine the P-V-T equation of state of hafnium. The previously described [Xia et al., Phys. Rev. B 42, 6736-6738 (1990)] phase transition from hcp ({alpha}) to simple hexagonal ({omega}) phase at 38 GPa at room temperature was not observed even up to 51 GPa. The {omega} phase was only observed at elevated temperatures. Our measurements have alsomore » improved the experimental constraint on the high P-T phase boundary between the {omega} phase and high pressure bcc ({beta}) phase of hafnium. Isothermal room temperature bulk modulus and its pressure derivative for the {alpha}-phase of hafnium were measured to be B{sub 0} = 112.9{+-}0.5 GPa and B{sub 0}'=3.29{+-}0.05, respectively. P-V-T data for the {alpha}-phase of hafnium was used to obtain a fit to a thermodynamic P-V-T equation of state based on model by Brosh et al. [CALPHAD 31, 173-185 (2007)].« less

  5. SEPARATION OF PLUTONIUM HYDROXIDE FROM BISMUTH HYDROXIDE

    DOEpatents

    Watt, G.W.

    1958-08-19

    An tmproved method is described for separating plutonium hydroxide from bismuth hydroxide. The end product of the bismuth phosphate processes for the separation amd concentration of plutonium is a inixture of bismuth hydroxide amd plutonium hydroxide. It has been found that these compounds can be advantageously separated by treatment with a reducing agent having a potential sufficient to reduce bismuth hydroxide to metalltc bisinuth but not sufficient to reduce the plutonium present. The resulting mixture of metallic bismuth and plutonium hydroxide can then be separated by treatment with a material which will dissolve plutonium hydroxide but not metallic bismuth. Sodiunn stannite is mentioned as a preferred reducing agent, and dilute nitric acid may be used as the separatory solvent.

  6. Hafnium transistor design for neural interfacing.

    PubMed

    Parent, David W; Basham, Eric J

    2008-01-01

    A design methodology is presented that uses the EKV model and the g(m)/I(D) biasing technique to design hafnium oxide field effect transistors that are suitable for neural recording circuitry. The DC gain of a common source amplifier is correlated to the structural properties of a Field Effect Transistor (FET) and a Metal Insulator Semiconductor (MIS) capacitor. This approach allows a transistor designer to use a design flow that starts with simple and intuitive 1-D equations for gain that can be verified in 1-D MIS capacitor TCAD simulations, before final TCAD process verification of transistor properties. The DC gain of a common source amplifier is optimized by using fast 1-D simulations and using slower, complex 2-D simulations only for verification. The 1-D equations are used to show that the increased dielectric constant of hafnium oxide allows a higher DC gain for a given oxide thickness. An additional benefit is that the MIS capacitor can be employed to test additional performance parameters important to an open gate transistor such as dielectric stability and ionic penetration.

  7. Etude de la nitruration carbothermique du dioxyde de hafnium par diffraction X à haute température

    NASA Astrophysics Data System (ADS)

    Pialoux, A.

    1993-03-01

    The carbothermal reduction of hafnium dioxide under atmospheric level nitrogen pressure has been investigated using a graphite resistance high temperature X-ray diffractometer up to around 2300 K. A carbon transfer reaction through the gaseous phase (N 2, CO/CO 2) is shown to precede, then to compete the direct reduction of the hafnium oxide by the graphite in pure nitrogen. A complex mechanism has been found that accounts for the formation of hafnium dioxynitride and possibly of three other hafnium oxynitrides, then of hafnium mononitride and hafnium monocarbonitride, along two different steps between 1613 and 1923 K. An evaluation has been made concerning the composition of these γ 1- HfO 2-xN x/2□ x/2 (CaF 2-type structure), γ 2- Hf 7O 11N 2, γ 3- Hf 7O 8N 4 (rhombohedral), γ 4- Hf 2ON 2 (Mn 2O 3-type structure), HfN and HfN 1-zC z (NaCl-type structure) phases, considering the variations of their lattice parameters and the available data in the literature, especially on the isomorphous compounds of zirconium. It must be emphasized the new γ 1- HfO 2-xN x/2 phase, the dilatation of which is linear ( overlineα = 12×10 -6K -1), shows a constant composition from 2158 down to 1473 K (x ≈ 0,2). But under 1473 K, inevitably, the hafnium dioxynitride disappears, and poorly crystallized monoclinic αHfO 2 and rhombohedral γ 2- Hf 7O 11N 2 are formed.

  8. RF sputtered silicon and hafnium nitrides as applied to 440C steel

    NASA Technical Reports Server (NTRS)

    Grill, A.; Aron, P. R.

    1984-01-01

    Silicon nitride and hafnium nitride coatings were deposited on oxidized and unoxidized 440C stainless steel substrates. Sputtering was done in mixtures of argon and nitrogen gases from pressed powder silicon nitride and from hafnium metal targets. The coatings and the interface between the coating and substrate were investigated by X-ray diffractometry, scanning electron microscopy, energy dispersive X-ray analysis and Auger electron spectroscopy. Oxide was found at all interfaces with an interface width of at least 600 A for the oxidized substrates and at least 300 A for the unoxidized substrates. Scratch test results demonstrate that the adhesion of hafnium nitride to both oxidized and unoxidized 440C is superior to that of silicon nitride. Oxidized 440C is found to have increased adhesion, to both nitrides, over that of unoxidized 440C. Coatings of both nitrides deposited at 8 mtorr were found to have increased adhesion to both oxidized and unoxidized 440C over those deposited at 20 mtorr.

  9. Tensile and stress-rupture behavior of hafnium carbide dispersed molybdenum and tungsten base alloy wires

    NASA Technical Reports Server (NTRS)

    Yun, Hee Mann; Titran, Robert H.

    1993-01-01

    The tensile strain rate sensitivity and the stress-rupture strength of Mo-base and W-base alloy wires, 380 microns in diameter, were determined over the temperature range from 1200 K to 1600 K. Three molybdenum alloy wires; Mo + 1.1w/o hafnium carbide (MoHfC), Mo + 25w/o W + 1.1w/o hafnium carbide (MoHfC+25W) and Mo + 45w/o W + 1.1w/o hafnium carbide (MoHfC+45W), and a W + 0.4w/o hafnium carbide (WHfC) tungsten alloy wire were evaluated. The tensile strength of all wires studied was found to have a positive strain rate sensitivity. The strain rate dependency increased with increasing temperature and is associated with grain broadening of the initial fibrous structures. The hafnium carbide dispersed W-base and Mo-base alloys have superior tensile and stress-rupture properties than those without HfC. On a density compensated basis the MoHfC wires exhibit superior tensile and stress-rupture strengths to the WHfC wires up to approximately 1400 K. Addition of tungsten in the Mo-alloy wires was found to increase the long-term stress rupture strength at temperatures above 1400 K. Theoretical calculations indicate that the strength and ductility advantage of the HfC dispersed alloy wires is due to the resistance to recrystallization imparted by the dispersoid.

  10. Mineral resource of the month: zirconium and hafnium

    USGS Publications Warehouse

    Gambogi, Joseph

    2007-01-01

    Zirconium and hafnium are corrosion-resistant metals that are grouped in the same family as titanium on the periodic table. The two elements commonly occur in oxide and silicate minerals and have significant economic importance in everything from ink, ceramics and golf shoes to nuclear fuel rods.

  11. Sodium Hydroxide and Calcium Hydroxide Hybrid Oxygen Bleaching with System

    NASA Astrophysics Data System (ADS)

    Doelle, K.; Bajrami, B.

    2018-01-01

    This study investigates the replacement of sodium hydroxide in the oxygen bleaching stage using a hybrid system consisting of sodium hydroxide calcium hydroxide. Commercial Kraft pulping was studied using yellow pine Kraft pulp obtained from a company in the US. The impact of sodium hydroxide, calcium hydroxide hybrid system in regard to concentration, reaction time and temperature for Kraft pulp was evaluated. The sodium hydroxide and calcium hydroxide dosage was varied between 0% and 15% based on oven dry fiber content. The bleaching reaction time was varied between 0 and 180 minutes whereas the bleaching temperature ranged between 70 °C and 110 °C. The ability to bleach pulp was measured by determining the Kappa number. Optimum bleaching results for the hybrid system were achieved with 4% sodium hydroxide and 2% calcium hydroxide content. Beyond this, the ability to bleach pulp decreased.

  12. SEPARATING HAFNIUM FROM ZIRCONIUM

    DOEpatents

    Lister, B.A.J.; Duncan, J.F.; Hutcheon, J.M.

    1956-08-21

    Substantially complete separation of zirconium from hafnium may be obtained by elution of ion exchange material, on which compounds of the elements are adsorbed, with an approximately normal solution of sulfuric acid. Preferably the acid concentration is between 0.8 N amd 1.2 N, amd should not exceed 1.5 N;. Increasing the concentration of sulfate ion in the eluting solution by addition of a soluble sulfate, such as sodium sulfate, has been found to be advantageous. The preferred ion exchange materials are sulfonated polystyrene resins such as Dowex 50,'' and are preferably arranged in a column through which the solutions are passed.

  13. Effect of cathode cooling efficiency and oxygen plasma gas pressure on the hafnium cathode wall temperature

    NASA Astrophysics Data System (ADS)

    Ashtekar, Koustubh; Diehl, Gregory; Hamer, John

    2012-10-01

    The hafnium cathode is widely used in DC plasma arc cutting (PAC) under an oxygen gas environment to cut iron and iron alloys. The hafnium erosion is always a concern which is controlled by the surface temperature. In this study, the effect of cathode cooling efficiency and oxygen gas pressure on the hafnium surface temperature are quantified. The two layer cathode sheath model is applied on the refractive hafnium surface while oxygen species (O2, O, O+, O++, e-) are considered within the thermal dis-equilibrium regime. The system of non-linear equations comprising of current density balance, heat flux balance at both the cathode surface and the sheath-ionization layer is coupled with the plasma gas composition solver. Using cooling heat flux, gas pressure and current density as inputs; the cathode wall temperature, electron temperature, and sheath voltage drop are calculated. Additionally, contribution of emitted electron current (Je) and ions current (Ji) to the total current flux are estimated. Higher gas pressure usually reduces Ji and increases Je that reduces the surface temperature by thermionic cooling.

  14. Low-voltage bendable pentacene thin-film transistor with stainless steel substrate and polystyrene-coated hafnium silicate dielectric.

    PubMed

    Yun, Dong-Jin; Lee, Seunghyup; Yong, Kijung; Rhee, Shi-Woo

    2012-04-01

    The hafnium silicate and aluminum oxide high-k dielectrics were deposited on stainless steel substrate using atomic layer deposition process and octadecyltrichlorosilane (OTS) and polystyrene (PS) were treated improve crystallinity of pentacene grown on them. Besides, the effects of the pentacene deposition condition on the morphologies, crystallinities and electrical properties of pentacene were characterized. Therefore, the surface treatment condition on dielectric and pentacene deposition conditions were optimized. The pentacene grown on polystyrene coated high-k dielectric at low deposition rate and temperature (0.2-0.3 Å/s and R.T.) showed the largest grain size (0.8-1.0 μm) and highest crystallinity among pentacenes deposited various deposition conditions, and the pentacene TFT with polystyrene coated high-k dielectric showed excellent device-performance. To decrease threshold voltage of pentacene TFT, the polystyrene-thickness on high-k dielectric was controlled using different concentration of polystyrene solution. As the polystyrene-thickness on hafnium silicate decreases, the dielectric constant of polystyrene/hafnium silicate increases, while the crystallinity of pentacene grown on polystyrene/hafnium silicate did not change. Using low-thickness polystyrene coated hafnium silicate dielectric, the high-performance and low voltage operating (<5 V) pentacene thin film transistor (μ: ~2 cm(2)/(V s), on/off ratio, >1 × 10(4)) and complementary inverter (DC gains, ~20) could be fabricated.

  15. Atomic layer deposition and characterization of hafnium oxide grown on silicon from tetrakis(diethylamino)hafnium and water vapor

    NASA Astrophysics Data System (ADS)

    Deshpande, Anand; Inman, Ronald; Jursich, Gregory; Takoudis, Christos

    2004-09-01

    In this work thin films of hafnium oxide are deposited on Si(100) substrates by means of atomic layer deposition (ALD) using tetrakis(diethylamino)hafnium and water vapor at substrate temperatures of 250-350ºC. Our system capabilities include fast transient delivery of reactive fluids, real-time vapor phase detection (in situ tunable diode laser hygrometer), precursor thermochemical capabilities, and ppt level elemental analysis by inductive coupling plasma mass spectrometry. The composition, purity, and other properties of the films and resulting interfaces are determined using x-ray and Fourier transform infrared spectroscopies, Z-contrast imaging and electron energy loss spectroscopy in a scanning transmission electron microscope with A˚ scale resolution, and spectroscopic ellipsometry. The observed ALD rate is ~1.4 A˚ per cycle. The nonuniformity across the film is less than 4%. Negligible carbon contamination is found in the resulting stoichiometric films under all conditions studied. The pulse sequence was optimized to prevent disastrous particulate problems while still minimizing purge times. The film deposition is investigated as a function of substrate temperature and reagent pulsing characteristics. A mild inverse temperature dependence of the ALD rate is observed. The initial stage of the HfO2 growth is investigated in detail.

  16. Review of anhydrous zirconium-hafnium separation techniques. Information circular/1984

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Skaggs, R.L.; Rogers, D.T.; Hunter, D.B.

    1983-12-01

    Sixteen nonaqueous techniques conceived to replace the current aqueous scheme for separating hafnium and zirconium tetrachlorides were reviewed and evaluated by the Bureau of Mines. The methods are divided into two classes: separation by fractional volatilization of the tetrachlorides, which takes advantage of the higher volatility of hafnium tetrachloride; and separation by chemical techniques, based on differences in chemical behavior of the two tetrachlorides. The criteria used to evaluate separation methods were temperature, pressure, separation factor per equilibrium stage, complexity, compatibility with existing technology, and potential for continuous operation. Three processes were selected as being most promising: (1) high-pressure distillation,more » (2) extractive distillation from a molten salt, and (3) preferential reduction of gaseous ZrCl4. Any of the proposed nonaqueous Hf-Zr separation schemes must be supplemented with additional purification to remove trace impurities.« less

  17. Nickel hydroxide electrode. 3: Thermogravimetric investigations of nickel (II) hydroxides

    NASA Technical Reports Server (NTRS)

    Dennstedt, W.; Loeser, W.

    1982-01-01

    Water contained in Ni hydroxide influences its electrochemical reactivity. The water content of alpha and beta Ni hydroxides is different with respect to the amount and bond strength. Thermogravimetric experiments show that the water of the beta Ni hydroxides exceeding the stoichiometric composition is completely removed at 160 deg. The water contained in the interlayers of the beta hydroxide, however, is removed only at higher temperatures, together with the water originating from the decomposition of the hydroxide. These differences are attributed to the formation of II bonds within the interlayers and between interlayers and adjacent main layers. An attempt is made to explain the relations between water content and the oxidizability of the Ni hydroxides.

  18. Development and characterization of ultrathin hafnium titanates as high permittivity gate insulators

    NASA Astrophysics Data System (ADS)

    Li, Min

    High permittivity or high-kappa materials are being developed for use as gate insulators for future ultrascaled metal oxide semiconductor field effect transistors (MOSFETs). Hafnium containing compounds are the leading candidates. Due to its moderate permittivity, however, it is difficult to achieve HfO2 gate structures with an EOT well below 1.0 nm. One approach to increase HfO2 permittivity is combining it with a very high-kappa material, such as TiO2. In this thesis, we systematically studied the electrical and physical characteristics of high-kappa hafnium titanates films as gate insulators. A series of HfxTi1-xO2 films with well-controlled composition were deposited using an MOCVD system. The physical properties of the films were analyzed using a variety of characterization techniques. X-ray micro diffraction indicates that the Ti-rich thin film is more immune to crystallization. TEM analysis showed that the thick stoichiometric HfTiO 4 film has an orthorhombic structure and large anisotropic grains. The C-V curves from the devices with the hafnium titanates films displayed relatively low hysteresis. In a certain composition range, the interfacial layer (IL) EOT and permittivity of HfxTi1-x O2 increases linearly with increasing Ti. The charge is negative for HfxTi1-xO2/IL and positive for Si/IL interface, and the magnitude increases as Hf increases. For ultra-thin films (less than 2 nm EOT), the leakage current increases with increasing HE Moreover, the Hf-rich sample has weaker temperature dependence of the current. In the MOSFET devices with the hafnium titanates films, normal transistor characteristics were observed, also electron mobility degradation. Next, we investigated the effects that different pre-deposition surface treatments, including HF dipping, NH3 surface nitridation, and HfO2 deposition, have on the electrical properties of hafnium titanates. Surface nitridation shows stronger effect than the thin HfO2 layer. The nitrided samples displayed a

  19. Evidence for oxygen vacancies movement during wake-up in ferroelectric hafnium oxide

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Starschich, S.; Böttger, U.; Menzel, S.

    The wake-up effect which is observed in ferroelectric hafnium oxide is investigated in yttrium doped hafnium oxide prepared by chemical solution deposition. It can be shown that not the amount of cycles but the duration of the applied electrical field is essential for the wake-up. Temperature dependent wake-up cycling in a range of −160 °C to 100 °C reveals a strong temperature activation of the wake-up, which can be attributed to ion rearrangement during cycling. By using asymmetrical electrodes, resistive valence change mechanism switching can be observed coincident with ferroelectric switching. From the given results, it can be concluded that redistribution ofmore » oxygen vacancies is the origin of the wake-up effect.« less

  20. Effect of hafnium doping on density of states in dual-target magnetron co-sputtering HfZnSnO thin film transistors

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Huang, Chuan-Xin; Li, Jun, E-mail: SHUniverjunli@163.com; Fu, Yi-Zhou

    2015-11-23

    This study investigates the effect of hafnium doping on the density of states (DOSs) in HfZnSnO thin film transistors fabricated by dual-target magnetron co-sputtering system. The DOSs is extracted by temperature-dependent field-effect measurements, and they decrease from 1.1 × 10{sup 17} to 4.6 × 10{sup 16 }eV/cm{sup 3} with increasing the hafnium concentrations. The behavior of DOSs for the increasing hafnium concentration HfZnSnO thin film transistors can be confirmed by both the reduction of ΔV{sub T} under bias stress and the trapping charges calculated by capacitance voltage measurements. It suggests that the reduction in DOSs due to the hafnium doping is closely related with themore » bias stability and thermal stability.« less

  1. Antibacterial action of calcium hydroxide vehicles and calcium hydroxide pastes.

    PubMed

    Pacios, María Gabriela; Silva, Clara; López, María Elena; Cecilia, Marta

    2012-11-01

    To evaluate the in vitro action of vehicles alone and with calcium hydroxide against different bacterial species. Agar plates were inoculated with the microbial suspensions, and wells were made and filled with the calcium hydroxide pastes and the vehicles used to prepare the pastes. The zones of inhibited bacterial growth were recorded, and the resulting measurements were statistically analyzed. Enterococcus faecalis was the most resistant microorganism to all medicaments. Calcium hydroxide + p-monochlorophenol; calcium hydroxide + p-monochlorophenol-propylene glycol pastes; and p-monochlorophenol, p-monochlorophenol-propylene glycol, and chlorhexidine gluconate gel alone showed the largest zones of inhibition against all the tested microorganisms. The vehicle used to prepare the calcium hydroxide paste might contribute to its antibacterial action. Chlorhexidine gluconate gel used alone, and camphorated p-monochlorophenol and camphorated p-monochlorophenol-propylene glycol as vehicles of calcium hydroxide, could be recommended, in an antimicrobial sense. © 2012 Wiley Publishing Asia Pty Ltd.

  2. Hafnium germanosilicate thin films for gate and capacitor dielectric applications: thermal stability studies

    NASA Astrophysics Data System (ADS)

    Addepalli, Swarna; Sivasubramani, Prasanna; El-Bouanani, Mohamed; Kim, Moon; Gnade, Bruce; Wallace, Robert

    2003-03-01

    The use of SiO_2-GeO2 mixtures in gate and capacitor dielectric applications is hampered by the inherent thermodynamic instability of germanium oxide. Studies to date have confirmed that germanium oxide is readily converted to elemental germanium [1,2]. In sharp contrast, germanium oxide is known to form stable compounds with transition metal oxides such as hafnium oxide (hafnium germanate, HfGeO_4) [3]. Thus, the incorporation of hafnium in SiO_2-GeO2 may be expected to enhance the thermal stability of germanium oxide via Hf-O-Ge bond formation. In addition, the introduction of a transition metal would simultaneously enhance the capacitance of the dielectric thereby permitting a thicker dielectric which reduces leakage current [4]. In this study, the thermal stability of PVD-grown hafnium germanosilicate (HfGeSiO) films was investigated. XPS, HR-TEM, C-V and I-V results of films after deposition and subsequent annealing treatments will be presented. The results indicate that the presence or formation of elemental germanium drastically affects the stability of the HfGeSiO films. This work is supported by DARPA through SPAWAR Grant No. N66001-00-1-8928, and the Texas Advanced Technology Program. References: [1] W. S. Liu, J .S. Chen, M.-A. Nicolet, V. Arbet-Engels, K. L. Wang, Journal of Applied Physics, 72, 4444 (1992), and, Applied Physics Letters, 62, 3321 (1993) [2] W. S. Liu, M. -A. Nicolet, H. -H. Park, B. -H. Koak, J. -W. Lee, Journal of Applied Physics, 78, 2631 (1995) [3] P. M. Lambert, Inorganic Chemistry, 37, 1352 (1998) [4] G. D. Wilk, R. M. Wallace and J. M. Anthony, Journal of Applied Physics, 89, 5243 (2001)

  3. Article having an improved platinum-aluminum-hafnium protective coating

    NASA Technical Reports Server (NTRS)

    Nagaraj, Bangalore Aswatha (Inventor); Williams, Jeffrey Lawrence (Inventor)

    2005-01-01

    An article protected by a protective coating has a substrate and a protective coating having an outer layer deposited upon the substrate surface and a diffusion zone formed by interdiffusion of the outer layer and the substrate. The protective coating includes platinum, aluminum, no more than about 2 weight percent hafnium, and substantially no silicon. The outer layer is substantially a single phase.

  4. Magnesium Hydroxide

    MedlinePlus

    Magnesium hydroxide is used on a short-term basis to treat constipation.This medication is sometimes prescribed ... Magnesium hydroxide come as a tablet and liquid to take by mouth. It usually is taken as ...

  5. Aluminum Hydroxide

    MedlinePlus

    Aluminum hydroxide is used for the relief of heartburn, sour stomach, and peptic ulcer pain and to ... Aluminum hydroxide comes as a capsule, a tablet, and an oral liquid and suspension. The dose and ...

  6. Hafnium-Based Bulk Metallic Glasses for Kinetic Energy Penetrators

    DTIC Science & Technology

    2004-12-01

    uranium -based (DU) and tungsten- nickel -iron (W-Ni-Fe) composite kinetic energy (KE) munitions is primarily ascribed to their high densities (U: ρ...based on an invariant point identified in the hafnium- copper- nickel ternary system. They are denser than zirconium-based glass-forming compositions...depleted- uranium penetrators. 1. INTRODUCTION 1.1 Criterion for Effective Kinetic Energy Penetrator Performance The lethality of depleted

  7. Inter-diffusion of copper and hafnium as studied by x-ray photoelectron spectroscopy

    NASA Astrophysics Data System (ADS)

    Pearson, Justin; Chourasia, A. R.

    The Cu/Hf interface has been characterized by x-ray photoelectron spectroscopy. Thin films (thicknesses ranging from 100 nm to 150 nm) of hafnium were deposited on a silicon substrate. About 80 nm of copper was then deposited on such samples. The e-beam method was used for the deposition. The samples were annealed for 30 min at temperatures of 100, 200, 300, 400, and 500°C. The inter-diffusion of copper and hafnium was investigated by sequential sputter depth profiling and x-ray photoelectron spectroscopy. The interdiffusion in each case was analyzed by the Matano-Boltzmann's procedure using the Fick's second law. The interdiffusion coefficients and the width of the interface as determined from the data have been correlated with the annealing temperature. Supported by Organized Research, TAMU-Commerce.

  8. The performance of hafnium and gadolinium self powered neutron detectors in the TREAT reactor

    NASA Astrophysics Data System (ADS)

    Imel, G. R.; Hart, P. R.

    1996-05-01

    The use of gadolinium and hafnium self powered neutron detectors in a transient reactor is described in this paper. The detectors were calibrated to the fission rate of U-235 using calibrated fission chambers; the calibration factors were tested in two reactors in steady state and found to be consistent. Calibration of the detectors in transient reactor conditions was done by using uranium wires that were analyzed by radiochemistry techniques to determine total fissions during the transient. This was correlated to the time-integrated current of the detectors during the transient. A temperature correction factor was derived to account for self-shielding effects in the hafnium and gadolinium detectors. The dynamic response of the detectors under transient conditions was studied, and found to be excellent.

  9. Ammonium hydroxide poisoning

    MedlinePlus

    Ammonium hydroxide is a colorless liquid chemical solution. It is in a class of substances called caustics. Ammonium hydroxide forms when ammonia dissolves in water. This article discusses poisoning from ...

  10. "Decarbonization" of an imino N-heterocyclic carbene via triple benzyl migration from hafnium

    USDA-ARS?s Scientific Manuscript database

    An imino N-heterocyclic carbene underwent three sequential benzyl migrations upon reaction with tetrabenzylhafnium, resulting in complete removal of the carbene carbon from the ligand. The resulting eneamido-amidinato hafnium complex showed alkene polymerization activity comparable to that of a prec...

  11. Sodium hydroxide poisoning

    MedlinePlus

    Sodium hydroxide is a very strong chemical. It is also known as lye and caustic soda. This ... poisoning from touching, breathing in (inhaling), or swallowing sodium hydroxide. This article is for information only. Do ...

  12. PROCESS OF RECOVERING ZIRCONIUM VALUES FROM HAFNIUM VALUES BY SOLVENT EXTRACTION WITH AN ALKYL PHOSPHATE

    DOEpatents

    Peppard, D.F.

    1960-02-01

    A process of separating hafnium nitrate from zirconium nitrate contained in a nitric acid solution by selectively. extracting the zirconium nitrate with a water-immiscible alkyl phosphate is reported.

  13. Ferroelectric memory based on molybdenum disulfide and ferroelectric hafnium oxide

    NASA Astrophysics Data System (ADS)

    Yap, Wui Chung; Jiang, Hao; Xia, Qiangfei; Zhu, Wenjuan

    Recently, ferroelectric hafnium oxide (HfO2) was discovered as a new type of ferroelectric material with the advantages of high coercive field, excellent scalability (down to 2.5 nm), and good compatibility with CMOS processing. In this work, we demonstrate, for the first time, 2D ferroelectric memories with molybdenum disulfide (MoS2) as the channel material and aluminum doped HfO2 as the ferroelectric gate dielectric. A 16 nm thick layer of HfO2, doped with 5.26% aluminum, was deposited via atomic layer deposition (ALD), then subjected to rapid thermal annealing (RTA) at 1000 °C, and the polarization-voltage characteristics of the resulting metal-ferroelectric-metal (MFM) capacitors were measured, showing a remnant polarization of 0.6 μC/cm2. Ferroelectric memories with embedded ferroelectric hafnium oxide stacks and monolayer MoS2 were fabricated. The transfer characteristics after program and erase pulses revealed a clear ferroelectric memory window. In addition, endurance (up to 10,000 cycles) of the devices were tested and effects associated with ferroelectric materials, such as the wake-up effect and polarization fatigue, were observed. This research can potentially lead to advances of 2D materials in low-power logic and memory applications.

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

    NASA Technical Reports Server (NTRS)

    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.

  15. 21 CFR 184.1631 - Potassium hydroxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Potassium hydroxide. 184.1631 Section 184.1631... Listing of Specific Substances Affirmed as GRAS § 184.1631 Potassium hydroxide. (a) Potassium hydroxide..., including pellets, flakes, sticks, lumps, and powders. Potassium hydroxide is obtained commercially from the...

  16. 21 CFR 184.1631 - Potassium hydroxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Potassium hydroxide. 184.1631 Section 184.1631... Listing of Specific Substances Affirmed as GRAS § 184.1631 Potassium hydroxide. (a) Potassium hydroxide..., including pellets, flakes, sticks, lumps, and powders. Potassium hydroxide is obtained commercially from the...

  17. 21 CFR 184.1428 - Magnesium hydroxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... is prepared as a white precipitate by the addition of sodium hydroxide to a water soluble magnesium... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Magnesium hydroxide. 184.1428 Section 184.1428... Listing of Specific Substances Affirmed as GRAS § 184.1428 Magnesium hydroxide. (a) Magnesium hydroxide...

  18. 21 CFR 184.1428 - Magnesium hydroxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... is prepared as a white precipitate by the addition of sodium hydroxide to a water soluble magnesium... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Magnesium hydroxide. 184.1428 Section 184.1428... Listing of Specific Substances Affirmed as GRAS § 184.1428 Magnesium hydroxide. (a) Magnesium hydroxide...

  19. 21 CFR 184.1631 - Potassium hydroxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Potassium hydroxide. 184.1631 Section 184.1631... GRAS § 184.1631 Potassium hydroxide. (a) Potassium hydroxide (KOH, CAS Reg. No. 1310-58-3) is also... powders. Potassium hydroxide is obtained commercially from the electrolysis of potassium chloride solution...

  20. 21 CFR 184.1428 - Magnesium hydroxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... addition of sodium hydroxide to a water soluble magnesium salt or by hydration of reactive grades of... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Magnesium hydroxide. 184.1428 Section 184.1428... GRAS § 184.1428 Magnesium hydroxide. (a) Magnesium hydroxide (Mg(OH)2, CAS Reg. No. 1309-42-8) occurs...

  1. Hafnium nitride buffer layers for growth of GaN on silicon

    DOEpatents

    Armitage, Robert D.; Weber, Eicke R.

    2005-08-16

    Gallium nitride is grown by plasma-assisted molecular-beam epitaxy on (111) and (001) silicon substrates using hafnium nitride buffer layers. Wurtzite GaN epitaxial layers are obtained on both the (111) and (001) HfN/Si surfaces, with crack-free thickness up to 1.2 {character pullout}m. However, growth on the (001) surface results in nearly stress-free films, suggesting that much thicker crack-free layers could be obtained.

  2. Hafnium isotope evidence for a transition in the dynamics of continental growth 3.2 Gyr ago.

    PubMed

    Næraa, T; Scherstén, A; Rosing, M T; Kemp, A I S; Hoffmann, J E; Kokfelt, T F; Whitehouse, M J

    2012-05-30

    Earth's lithosphere probably experienced an evolution towards the modern plate tectonic regime, owing to secular changes in mantle temperature. Radiogenic isotope variations are interpreted as evidence for the declining rates of continental crustal growth over time, with some estimates suggesting that over 70% of the present continental crustal reservoir was extracted by the end of the Archaean eon. Patterns of crustal growth and reworking in rocks younger than three billion years (Gyr) are thought to reflect the assembly and break-up of supercontinents by Wilson cycle processes and mark an important change in lithosphere dynamics. In southern West Greenland numerous studies have, however, argued for subduction settings and crust growth by arc accretion back to 3.8 Gyr ago, suggesting that modern-day tectonic regimes operated during the formation of the earliest crustal rock record. Here we report in situ uranium-lead, hafnium and oxygen isotope data from zircons of basement rocks in southern West Greenland across the critical time period during which modern-like tectonic regimes could have initiated. Our data show pronounced differences in the hafnium isotope-time patterns across this interval, requiring changes in the characteristics of the magmatic protolith. The observations suggest that 3.9-3.5-Gyr-old rocks differentiated from a >3.9-Gyr-old source reservoir with a chondritic to slightly depleted hafnium isotope composition. In contrast, rocks formed after 3.2 Gyr ago register the first additions of juvenile depleted material (that is, new mantle-derived crust) since 3.9 Gyr ago, and are characterized by striking shifts in hafnium isotope ratios similar to those shown by Phanerozoic subduction-related orogens. These data suggest a transitional period 3.5-3.2 Gyr ago from an ancient (3.9-3.5 Gyr old) crustal evolutionary regime unlike that of modern plate tectonics to a geodynamic setting after 3.2 Gyr ago that involved juvenile crust generation by plate

  3. Slow DNA Transport through Nanopores in Hafnium Oxide Membranes

    PubMed Central

    Bell, David C.; Cohen-Karni, Tzahi; Rosenstein, Jacob K.; Wanunu, Meni

    2016-01-01

    We present a study of double- and single-stranded DNA transport through nanopores fabricated in ultrathin (2–7 nm thick) free-standing hafnium oxide (HfO2) membranes. The high chemical stability of ultrathin HfO2 enables long-lived experiments with <2 nm diameter pores that last several hours, in which we observe >50 000 DNA translocations with no detectable pore expansion. Mean DNA velocities are slower than velocities through comparable silicon nitride pores, providing evidence that HfO2 nanopores have favorable physicochemical interactions with nucleic acids that can be leveraged to slow down DNA in a nanopore. PMID:24083444

  4. Cathodoluminescence Study of Hafnium Oxide

    NASA Astrophysics Data System (ADS)

    Purcell, Emily; Hengehold, Robert; McClory, John

    2011-10-01

    Hafnium dioxide (HfO2) is increasingly being used in place of silicon oxide as a gate insulator in field effect transistors. This is primarily due to its high dielectric constant, κ, of 25. Samples of HfO2 were grown by either atomic layer deposition (ALD) or pulsed laser deposition (PLD), with the PLD samples having assorted substrate temperatures during deposition (300 C, 500 C, and 750 C). Cathodoluminescence (CL) was chosen as the technique used for studying these HfO2 samples. The CL system used was capable of beam energies ranging from 1 keV to 20 keV and beam currents ranging from 10 μA to 50 μA. A Monte Carlo calculation using CASINO software was performed in order to determine the beam energy for the desired depth of penetration. Measurements were taken at sample temperatures ranging from 7K (closed cycled cryostat) to 300K (room temperature), as well as at various beam energies and beam currents. Comparison will be made between the PLD and ALD spectra.

  5. Self-cleaning and surface chemical reactions during hafnium dioxide atomic layer deposition on indium arsenide.

    PubMed

    Timm, Rainer; Head, Ashley R; Yngman, Sofie; Knutsson, Johan V; Hjort, Martin; McKibbin, Sarah R; Troian, Andrea; Persson, Olof; Urpelainen, Samuli; Knudsen, Jan; Schnadt, Joachim; Mikkelsen, Anders

    2018-04-12

    Atomic layer deposition (ALD) enables the ultrathin high-quality oxide layers that are central to all modern metal-oxide-semiconductor circuits. Crucial to achieving superior device performance are the chemical reactions during the first deposition cycle, which could ultimately result in atomic-scale perfection of the semiconductor-oxide interface. Here, we directly observe the chemical reactions at the surface during the first cycle of hafnium dioxide deposition on indium arsenide under realistic synthesis conditions using photoelectron spectroscopy. We find that the widely used ligand exchange model of the ALD process for the removal of native oxide on the semiconductor and the simultaneous formation of the first hafnium dioxide layer must be significantly revised. Our study provides substantial evidence that the efficiency of the self-cleaning process and the quality of the resulting semiconductor-oxide interface can be controlled by the molecular adsorption process of the ALD precursors, rather than the subsequent oxide formation.

  6. 21 CFR 582.1428 - Magnesium hydroxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Magnesium hydroxide. 582.1428 Section 582.1428 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1428 Magnesium hydroxide. (a) Product. Magnesium hydroxide. (b) Conditions of use. This...

  7. 21 CFR 582.1428 - Magnesium hydroxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Magnesium hydroxide. 582.1428 Section 582.1428 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1428 Magnesium hydroxide. (a) Product. Magnesium hydroxide. (b) Conditions of use. This...

  8. 21 CFR 582.1428 - Magnesium hydroxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Magnesium hydroxide. 582.1428 Section 582.1428 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1428 Magnesium hydroxide. (a) Product. Magnesium hydroxide. (b) Conditions of use. This...

  9. 21 CFR 582.1428 - Magnesium hydroxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Magnesium hydroxide. 582.1428 Section 582.1428 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1428 Magnesium hydroxide. (a) Product. Magnesium hydroxide. (b) Conditions of use. This...

  10. 21 CFR 582.1428 - Magnesium hydroxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Magnesium hydroxide. 582.1428 Section 582.1428 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1428 Magnesium hydroxide. (a) Product. Magnesium hydroxide. (b) Conditions of use. This...

  11. 21 CFR 582.1205 - Calcium hydroxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Calcium hydroxide. 582.1205 Section 582.1205 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1205 Calcium hydroxide. (a) Product. Calcium hydroxide. (b) Conditions of use. This...

  12. 21 CFR 582.1631 - Potassium hydroxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Potassium hydroxide. 582.1631 Section 582.1631 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1631 Potassium hydroxide. (a) Product. Potassium hydroxide. (b) Conditions of use. This...

  13. 21 CFR 582.1631 - Potassium hydroxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Potassium hydroxide. 582.1631 Section 582.1631 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1631 Potassium hydroxide. (a) Product. Potassium hydroxide. (b) Conditions of use. This...

  14. 21 CFR 582.1631 - Potassium hydroxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Potassium hydroxide. 582.1631 Section 582.1631 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1631 Potassium hydroxide. (a) Product. Potassium hydroxide. (b) Conditions of use. This...

  15. 21 CFR 582.1631 - Potassium hydroxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Potassium hydroxide. 582.1631 Section 582.1631 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1631 Potassium hydroxide. (a) Product. Potassium hydroxide. (b) Conditions of use. This...

  16. 21 CFR 582.1631 - Potassium hydroxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Potassium hydroxide. 582.1631 Section 582.1631 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1631 Potassium hydroxide. (a) Product. Potassium hydroxide. (b) Conditions of use. This...

  17. 21 CFR 184.1428 - Magnesium hydroxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... salt or by hydration of reactive grades of magnesium oxide. (b) The ingredient meets the specifications... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Magnesium hydroxide. 184.1428 Section 184.1428... Listing of Specific Substances Affirmed as GRAS § 184.1428 Magnesium hydroxide. (a) Magnesium hydroxide...

  18. 21 CFR 582.1763 - Sodium hydroxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Sodium hydroxide. 582.1763 Section 582.1763 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1763 Sodium hydroxide. (a) Product. Sodium hydroxide. (b) Conditions of use. This substance...

  19. 21 CFR 582.1763 - Sodium hydroxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Sodium hydroxide. 582.1763 Section 582.1763 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1763 Sodium hydroxide. (a) Product. Sodium hydroxide. (b) Conditions of use. This substance...

  20. 21 CFR 582.1763 - Sodium hydroxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Sodium hydroxide. 582.1763 Section 582.1763 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1763 Sodium hydroxide. (a) Product. Sodium hydroxide. (b) Conditions of use. This substance...

  1. 21 CFR 582.1763 - Sodium hydroxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Sodium hydroxide. 582.1763 Section 582.1763 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1763 Sodium hydroxide. (a) Product. Sodium hydroxide. (b) Conditions of use. This substance...

  2. 21 CFR 582.1763 - Sodium hydroxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Sodium hydroxide. 582.1763 Section 582.1763 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1763 Sodium hydroxide. (a) Product. Sodium hydroxide. (b) Conditions of use. This substance...

  3. 21 CFR 184.1428 - Magnesium hydroxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... hydration of reactive grades of magnesium oxide. (b) The ingredient meets the specifications of the Food... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Magnesium hydroxide. 184.1428 Section 184.1428 Food... Specific Substances Affirmed as GRAS § 184.1428 Magnesium hydroxide. (a) Magnesium hydroxide (Mg(OH)2, CAS...

  4. Aminopyridinate-FI hybrids, their hafnium and titanium complexes, and their application in the living polymerization of 1-hexene.

    PubMed

    Haas, Isabelle; Dietel, Thomas; Press, Konstantin; Kol, Moshe; Kempe, Rhett

    2013-10-11

    Based on two well-established ligand systems, the aminopyridinato (Ap) and the phenoxyimine (FI) ligand systems, new Ap-FI hybrid ligands were developed. Four different Ap-FI hybrid ligands were synthesized through a simple condensation reaction and fully characterized. The reaction of hafnium tetrabenzyl with all four Ap-FI hybrid ligands exclusively led to mono(Ap-FI) complexes of the type [(Ap-FI)HfBn2 ]. The ligands acted as tetradentate dianionic chelates. Upon activation with tris(pentafluorophenyl)borane, the hafnium-dibenzyl complexes led to highly active catalysts for the polymerization of 1-hexene. Ultrahigh molecular weights and extremely narrow polydispersities support the living nature of this polymerization process. A possible deactivation product of the hafnium catalysts was characterized by single-crystal X-ray analysis and is discussed. The coordination modes of these new ligands were studied with the help of model titanium complexes. The reaction of titanium(IV) isopropoxide with ligand 1 led to a mono(Ap-FI) complex, which showed the desired fac-mer coordination mode. Titanium (IV) isopropoxide reacted with ligand 4 to give a complex of the type [(ApH-FI)2 Ti(OiPr)2 ], which featured the ligand in its monoanionic form. The two titanium complexes were characterized by X-ray crystal-structure analysis. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. 21 CFR 184.1205 - Calcium hydroxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Calcium hydroxide. 184.1205 Section 184.1205 Food... Specific Substances Affirmed as GRAS § 184.1205 Calcium hydroxide. (a) Calcium hydroxide (Ca(OH)2, CAS Reg. No. 1305-62-0) is also known as slaked lime or calcium hydrate. It is produced by the hydration of...

  6. 21 CFR 184.1763 - Sodium hydroxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Sodium hydroxide. 184.1763 Section 184.1763 Food... Specific Substances Affirmed as GRAS § 184.1763 Sodium hydroxide. (a) Sodium hydroxide (NaOH, CAS Reg. No. 1310-73-2) is also known as sodium hydrate, soda lye, caustic soda, white caustic, and lye. The...

  7. 21 CFR 184.1763 - Sodium hydroxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Sodium hydroxide. 184.1763 Section 184.1763 Food... Specific Substances Affirmed as GRAS § 184.1763 Sodium hydroxide. (a) Sodium hydroxide (NaOH, CAS Reg. No. 1310-73-2) is also known as sodium hydrate, soda lye, caustic soda, white caustic, and lye. The...

  8. 21 CFR 184.1763 - Sodium hydroxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium hydroxide. 184.1763 Section 184.1763 Food... Specific Substances Affirmed as GRAS § 184.1763 Sodium hydroxide. (a) Sodium hydroxide (NaOH, CAS Reg. No. 1310-73-2) is also known as sodium hydrate, soda lye, caustic soda, white caustic, and lye. The...

  9. 21 CFR 184.1763 - Sodium hydroxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Sodium hydroxide. 184.1763 Section 184.1763 Food... Specific Substances Affirmed as GRAS § 184.1763 Sodium hydroxide. (a) Sodium hydroxide (NaOH, CAS Reg. No. 1310-73-2) is also known as sodium hydrate, soda lye, caustic soda, white caustic, and lye. The...

  10. 21 CFR 184.1763 - Sodium hydroxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Sodium hydroxide. 184.1763 Section 184.1763 Food... GRAS § 184.1763 Sodium hydroxide. (a) Sodium hydroxide (NaOH, CAS Reg. No. 1310-73-2) is also known as sodium hydrate, soda lye, caustic soda, white caustic, and lye. The empirical formula is NaOH. Sodium...

  11. 21 CFR 184.1205 - Calcium hydroxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium hydroxide. 184.1205 Section 184.1205 Food... GRAS § 184.1205 Calcium hydroxide. (a) Calcium hydroxide (Ca(OH)2, CAS Reg. No. 1305-62-0) is also known as slaked lime or calcium hydrate. It is produced by the hydration of lime. (b) The ingredient...

  12. Processing and characterization of boron carbide-hafnium diboride ceramics

    NASA Astrophysics Data System (ADS)

    Brown-Shaklee, Harlan James

    Hafnium diboride based ceramics are promising candidate materials for advanced aerospace and nuclear reactor components. The effectiveness of boron carbide and carbon as HfB2 sintering additives was systematically evaluated. In the first stage of the research, boron carbide and carbon additives were found to improve the densification behavior of milled HfB2 powder in part by removing oxides at the HfB2 surface during processing. Boron carbide additives reduced the hot pressing temperature of HfB2 by 150°C compared to carbon, which reduced the hot pressing temperature by ˜50°C. Reduction of oxide impurities alone could not explain the difference in sintering enhancement, however, and other mechanisms of enhancement were evaluated. Boron carbides throughout the homogeneity range were characterized to understand other mechanisms of sintering enhancement in HfB2. Heavily faulted carbon rich and boron rich boron carbides were synthesized for addition to HfB2. The greatest enhancement to densification was observed in samples containing boron- and carbon-rich compositions whereas B6.5 C provided the least enhancement to densification. It is proposed that carbon rich and boron rich boron carbides create boron and hafnium point defects in HfB2, respectively, which facilitate densification. Evaluation of the thermal conductivity (kth) between room temperature and 2000°C suggested that the stoichiometry of the boron carbide additives did not significantly affect kth of HfB2-BxC composites. The improved sinterability and the high kth (˜110 W/m-K at 300K and ˜90 W/m-K at 1000°C ) of HfB2-BxC ceramics make them excellent candidates for isotopically enriched reactor control materials.

  13. Dissolution mechanism of aluminum hydroxides in acid media

    NASA Astrophysics Data System (ADS)

    Lainer, Yu. A.; Gorichev, I. G.; Tuzhilin, A. S.; Gololobova, E. G.

    2008-08-01

    The effects of the concentration, temperature, and potential at the hydroxide/electrolyte interface on the aluminum hydroxide dissolution in sulfuric, hydrochloric, and perchloric acids are studied. The limiting stage of the aluminum hydroxide dissolution in the acids is found to be the transition of the complexes that form on the aluminum hydroxide surface from the solid phase into the solution. The results of the calculation of the acid-base equilibrium constants at the oxide (hydroxide)/solution interface using the experimental data on the potentiometric titration of Al2O3 and AlOOH suspensions are analyzed. A mechanism is proposed for the dissolution of aluminum hydroxides in acid media.

  14. Layered zinc hydroxide salts: delamination, preferred orientation of hydroxide lamellae, and formation of ZnO nanodiscs.

    PubMed

    Demel, Jan; Pleštil, Josef; Bezdička, Petr; Janda, Pavel; Klementová, Mariana; Lang, Kamil

    2011-08-15

    Delamination of layered zinc hydroxide salts (LZH) into hydroxide layers provides nanobuilding blocs of a two-dimensional anisotropy. The methodology, extent of delamination, the size and stability of hydroxide lamellae are described in detail. The ability of lamellae to restack to form oriented hydroxide films depends on the solvent, original LZH salt, and conditions used for delamination. The most interesting results were obtained using LZH intercalated with dodecyl sulfate anions and LZH nitrate delaminated in butanol at 60 °C and in formamide at room temperature, respectively. The former method produces hydroxide lamellae of a lateral size of ca. 10-20 nm. The inner structure of the hydroxide layers is conserved and separated lamellae restack to the original layered structure of LZH dodecyl sulfate. The latter method yields lamellae with a size decreasing from 73.3 nm to 10 nm after a 2-week aging, while their thickness is nearly constant (2.6-3.8 nm). However, the use of formamide is complicated by the formation of Zn(II) formate. The major part of LZH intercalated with dodecyl sulfate anions is transformed during the delamination procedure to anisotropic ZnO nanoparticles, either needle-like particles prolonged in the [0 0 1] direction or disc-like particles flattened along the (0 0 1) plane. Copyright © 2011 Elsevier Inc. All rights reserved.

  15. Metal–Organic Nanosheets Formed via Defect-Mediated Transformation of a Hafnium Metal–Organic Framework

    PubMed Central

    2017-01-01

    We report a hafnium-containing MOF, hcp UiO-67(Hf), which is a ligand-deficient layered analogue of the face-centered cubic fcu UiO-67(Hf). hcp UiO-67 accommodates its lower ligand:metal ratio compared to fcu UiO-67 through a new structural mechanism: the formation of a condensed “double cluster” (Hf12O8(OH)14), analogous to the condensation of coordination polyhedra in oxide frameworks. In oxide frameworks, variable stoichiometry can lead to more complex defect structures, e.g., crystallographic shear planes or modules with differing compositions, which can be the source of further chemical reactivity; likewise, the layered hcp UiO-67 can react further to reversibly form a two-dimensional metal–organic framework, hxl UiO-67. Both three-dimensional hcp UiO-67 and two-dimensional hxl UiO-67 can be delaminated to form metal–organic nanosheets. Delamination of hcp UiO-67 occurs through the cleavage of strong hafnium-carboxylate bonds and is effected under mild conditions, suggesting that defect-ordered MOFs could be a productive route to porous two-dimensional materials. PMID:28343394

  16. Metal-Organic Nanosheets Formed via Defect-Mediated Transformation of a Hafnium Metal-Organic Framework.

    PubMed

    Cliffe, Matthew J; Castillo-Martínez, Elizabeth; Wu, Yue; Lee, Jeongjae; Forse, Alexander C; Firth, Francesca C N; Moghadam, Peyman Z; Fairen-Jimenez, David; Gaultois, Michael W; Hill, Joshua A; Magdysyuk, Oxana V; Slater, Ben; Goodwin, Andrew L; Grey, Clare P

    2017-04-19

    We report a hafnium-containing MOF, hcp UiO-67(Hf), which is a ligand-deficient layered analogue of the face-centered cubic fcu UiO-67(Hf). hcp UiO-67 accommodates its lower ligand:metal ratio compared to fcu UiO-67 through a new structural mechanism: the formation of a condensed "double cluster" (Hf 12 O 8 (OH) 14 ), analogous to the condensation of coordination polyhedra in oxide frameworks. In oxide frameworks, variable stoichiometry can lead to more complex defect structures, e.g., crystallographic shear planes or modules with differing compositions, which can be the source of further chemical reactivity; likewise, the layered hcp UiO-67 can react further to reversibly form a two-dimensional metal-organic framework, hxl UiO-67. Both three-dimensional hcp UiO-67 and two-dimensional hxl UiO-67 can be delaminated to form metal-organic nanosheets. Delamination of hcp UiO-67 occurs through the cleavage of strong hafnium-carboxylate bonds and is effected under mild conditions, suggesting that defect-ordered MOFs could be a productive route to porous two-dimensional materials.

  17. 40 CFR 721.4600 - Recovered metal hydroxide.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Recovered metal hydroxide. 721.4600... Substances § 721.4600 Recovered metal hydroxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a recovered metal hydroxide (PMN P-91-809...

  18. On the Nickel Hydroxide Electrode. I. On Nickel (II) Hydroxide Hydrate,

    DTIC Science & Technology

    1980-10-27

    1 - 4.60 A), and the hydrous form is halloysite , AI 2Si2 O5 (OH)4 .2H20 with d001 - 10.25 A (analogous to a-3Ni(OH)2 .2H20 with do01 - 8.07 A). On...heating of halloysite , the entire intermediate layer water is lost at about 1500 C, as for a nickel hydroxide, without the hydroxide layer separation...significantly reducing to meta- halloysite . 13 The conversion of the a form under the influence of alkali goes only in one direction. This monotropic

  19. 21 CFR 73.1326 - Chromium hydroxide green.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1326 Chromium hydroxide green. (a) Identity. (1) The color additive chromium hydroxide green is principally hydrated chromic sesquioxide (Cr2O3·XH2O). (2) Color additive mixtures for drug use made with chromium hydroxide green may contain only those...

  20. 21 CFR 582.1139 - Ammonium hydroxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Additives § 582.1139 Ammonium hydroxide. (a) Product. Ammonium hydroxide. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding...

  1. 21 CFR 582.1205 - Calcium hydroxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Additives § 582.1205 Calcium hydroxide. (a) Product. Calcium hydroxide. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding...

  2. 21 CFR 582.1205 - Calcium hydroxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... Additives § 582.1205 Calcium hydroxide. (a) Product. Calcium hydroxide. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding...

  3. 21 CFR 582.1139 - Ammonium hydroxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... Additives § 582.1139 Ammonium hydroxide. (a) Product. Ammonium hydroxide. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding...

  4. 21 CFR 582.1205 - Calcium hydroxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... Additives § 582.1205 Calcium hydroxide. (a) Product. Calcium hydroxide. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding...

  5. 21 CFR 582.1139 - Ammonium hydroxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... Additives § 582.1139 Ammonium hydroxide. (a) Product. Ammonium hydroxide. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding...

  6. 21 CFR 582.1139 - Ammonium hydroxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Additives § 582.1139 Ammonium hydroxide. (a) Product. Ammonium hydroxide. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding...

  7. 21 CFR 582.1139 - Ammonium hydroxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Additives § 582.1139 Ammonium hydroxide. (a) Product. Ammonium hydroxide. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding...

  8. 21 CFR 582.1205 - Calcium hydroxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Additives § 582.1205 Calcium hydroxide. (a) Product. Calcium hydroxide. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding...

  9. Pretreatment of rapeseed straw by sodium hydroxide.

    PubMed

    Kang, Kyeong Eop; Jeong, Gwi-Taek; Park, Don-Hee

    2012-06-01

    Pretreatment method for rapeseed straw by sodium hydroxide was investigated for production of bioethanol and biobutanol. Various pretreatment parameters, including temperature, time, and sodium hydroxide concentration were optimized using a statistical method which is a central composite design of response surface methodology. In the case of sodium hydroxide pretreatment, optimal pretreatment conditions were found to be 7.9% sodium hydroxide concentration, 5.5 h of reaction time, and 68.4 °C of reaction temperature. The maximum glucose yield which can be recovered by enzymatic hydrolysis at the optimum conditions was 95.7% and the experimental result was 94.0 ± 4.8%. This experimental result was in agreement with the model prediction. An increase of surface area and pore size in pretreated rapeseed straw by sodium hydroxide pretreatment was observed by scanning electron microscope.

  10. 21 CFR 73.1326 - Chromium hydroxide green.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Chromium hydroxide green. 73.1326 Section 73.1326... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1326 Chromium hydroxide green. (a) Identity. (1) The color additive chromium hydroxide green is principally hydrated chromic sesquioxide (Cr2O3·XH2O...

  11. Layered double hydroxide stability. 1. Relative stabilities of layered double hydroxides and their simple counterparts

    NASA Technical Reports Server (NTRS)

    Boclair, J. W.; Braterman, P. S.

    1999-01-01

    Solutions containing di- and trivalent metal chlorides [M(II) = Mg2+, Zn2+, Co2+, Ni2+, Mn2+; M(III) = Al3+, Fe3+] were titrated with NaOH to yield hydrotalcite-like layered double hydroxides (LDH), [[M(II)]1-x[M(III)]x(OH)2][Cl]x yH2O, by way of M(III) hydroxide/hydrous oxide intermediates. Analysis of the resultant titration curves yields nominal solubility constants for the LDH. The corresponding LDH stabilities are in the order Mg < Mn < Co approximately Ni < Zn for M(II) and Al < Fe for M(III). The stability of LDH relative to the separate metal hydroxides/hydrous oxides is discussed.

  12. 21 CFR 73.1010 - Alumina (dried aluminum hydroxide).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1010 Alumina (dried aluminum hydroxide). (a) Identity. (1) The color additive alumina (dried aluminum hydroxide) is a white, odorless, tasteless, amorphous powder consisting essentially of aluminum hydroxide (Al2 O3· XH2 O). (2) Color additive...

  13. Hydroxide Solvation and Transport in Anion Exchange Membranes.

    PubMed

    Chen, Chen; Tse, Ying-Lung Steve; Lindberg, Gerrick E; Knight, Chris; Voth, Gregory A

    2016-01-27

    Understanding hydroxide solvation and transport in anion exchange membranes (AEMs) can provide important insight into the design principles of these new membranes. To accurately model hydroxide solvation and transport, we developed a new multiscale reactive molecular dynamics model for hydroxide in aqueous solution, which was then subsequently modified for an AEM material. With this model, we investigated the hydroxide solvation structure and transport mechanism in the membrane. We found that a relatively even separation of the rigid side chains produces a continuous overlapping region for hydroxide transport that is made up of the first hydration shell of the tethered cationic groups. Our results show that hydroxide has a significant preference for this overlapping region, transporting through it and between the AEM side chains with substantial contributions from both vehicular (standard diffusion) and Grotthuss (proton hopping) mechanisms. Comparison of the AEM with common proton exchange membranes (PEMs) showed that the excess charge is less delocalized in the AEM than the PEMs, which is correlated with a higher free energy barrier for proton transfer reactions. The vehicular mechanism also contributes considerably more than the Grotthuss mechanism for hydroxide transport in the AEM, while our previous studies of PEM systems showed a larger contribution from the Grotthuss mechanism than the vehicular mechanism for proton transport. The activation energy barrier for hydroxide diffusion in the AEM is greater than that for proton diffusion in PEMs, implying a more significant enhancement of ion transport in the AEM at elevated temperatures.

  14. Calcium hydroxide poisoning

    MedlinePlus

    These products contain calcium hydroxide: Cement Limewater Many industrial solvents and cleaners (hundreds to thousands of construction products, flooring strippers, brick cleaners, cement thickening products, and many ...

  15. 21 CFR 872.3250 - Calcium hydroxide cavity liner.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Calcium hydroxide cavity liner. 872.3250 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3250 Calcium hydroxide cavity liner. (a) Identification. A calcium hydroxide cavity liner is a device material intended to be applied to the interior of a...

  16. 21 CFR 872.3250 - Calcium hydroxide cavity liner.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Calcium hydroxide cavity liner. 872.3250 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3250 Calcium hydroxide cavity liner. (a) Identification. A calcium hydroxide cavity liner is a device material intended to be applied to the interior of a...

  17. 21 CFR 872.3250 - Calcium hydroxide cavity liner.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Calcium hydroxide cavity liner. 872.3250 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3250 Calcium hydroxide cavity liner. (a) Identification. A calcium hydroxide cavity liner is a device material intended to be applied to the interior of a...

  18. 21 CFR 872.3250 - Calcium hydroxide cavity liner.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Calcium hydroxide cavity liner. 872.3250 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3250 Calcium hydroxide cavity liner. (a) Identification. A calcium hydroxide cavity liner is a device material intended to be applied to the interior of a...

  19. 21 CFR 872.3250 - Calcium hydroxide cavity liner.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Calcium hydroxide cavity liner. 872.3250 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3250 Calcium hydroxide cavity liner. (a) Identification. A calcium hydroxide cavity liner is a device material intended to be applied to the interior of a...

  20. Hydroxide Solvation and Transport in Anion Exchange Membranes

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Chen, Chen; Tse, Ying-Lung Steve; Lindberg, Gerrick E.

    Understanding hydroxide solvation and transport in anion exchange membranes (AEMs) can provide important insight into the design principles of these new membranes. To accurately model hydroxide solvation and transport, we developed a new multiscale reactive molecular dynamics model for hydroxide in aqueous solution, which was then subsequently modified for an AEM material. With this model, we investigated the hydroxide solvation structure and transport mechanism in the membrane. We found that a relatively even separation of the rigid side chains produces a continuous overlapping region for hydroxide transport that is made up of the first hydration shell of the tethered cationicmore » groups. Our results show that hydroxide has a significant preference for this overlapping region, transporting through it and between the AEM side chains with substantial contributions from both vehicular (standard diffusion) and Grotthuss (proton hopping) mechanisms. Comparison of the AEM with common proton exchange membranes (PEMs) showed that the excess charge is less delocalized in the AEM than the PEMs, which is correlated with a higher free energy barrier for proton transfer reactions. The vehicular mechanism also contributes considerably more than the Grotthuss mechanism for hydroxide transport in the AEM, while our previous studies of PEM systems showed a larger contribution from the Grotthuss mechanism than the vehicular mechanism for proton transport. The activation energy barrier for hydroxide diffusion in the AEM is greater than that for proton diffusion in PEMs, implying a more significant enhancement of ion transport in the AEM at elevated temperatures.« less

  1. Advances in aluminum hydroxide-based adjuvant research and its mechanism.

    PubMed

    He, Peng; Zou, Yening; Hu, Zhongyu

    2015-01-01

    In the past few decades, hundreds of materials have been tried as adjuvant; however, only aluminum-based adjuvants continue to be used widely in the world. Aluminum hydroxide, aluminum phosphate and alum constitute the main forms of aluminum used as adjuvants. Among these, aluminum hydroxide is the most commonly used chemical as adjuvant. In spite of its wide spread use, surprisingly, the mechanism of how aluminum hydroxide-based adjuvants exert their beneficial effects is still not fully understood. Current explanations for the mode of action of aluminum hydroxide-based adjuvants include, among others, the repository effect, pro-phagocytic effect, and activation of the pro-inflammatory NLRP3 pathway. These collectively galvanize innate as well as acquired immune responses and activate the complement system. Factors that have a profound influence on responses evoked by aluminum hydroxide-based adjuvant applications include adsorption rate, strength of the adsorption, size and uniformity of aluminum hydroxide particles, dosage of adjuvant, and the nature of antigens. Although vaccines containing aluminum hydroxide-based adjuvants are beneficial, sometimes they cause adverse reactions. Further, these vaccines cannot be stored frozen. Until recently, aluminum hydroxide-based adjuvants were known to preferentially prime Th2-type immune responses. However, results of more recent studies show that depending on the vaccination route, aluminum hydroxide-based adjuvants can enhance both Th1 as well as Th2 cellular responses. Advances in systems biology have opened up new avenues for studying mechanisms of aluminum hydroxide-based adjuvants. These will assist in scaling new frontiers in aluminum hydroxide-based adjuvant research that include improvement of formulations, use of nanoparticles of aluminum hydroxide and development of composite adjuvants.

  2. Advances in aluminum hydroxide-based adjuvant research and its mechanism

    PubMed Central

    He, Peng; Zou, Yening; Hu, Zhongyu

    2015-01-01

    In the past few decades, hundreds of materials have been tried as adjuvant; however, only aluminum-based adjuvants continue to be used widely in the world. Aluminum hydroxide, aluminum phosphate and alum constitute the main forms of aluminum used as adjuvants. Among these, aluminum hydroxide is the most commonly used chemical as adjuvant. In spite of its wide spread use, surprisingly, the mechanism of how aluminum hydroxide-based adjuvants exert their beneficial effects is still not fully understood. Current explanations for the mode of action of aluminum hydroxide-based adjuvants include, among others, the repository effect, pro-phagocytic effect, and activation of the pro-inflammatory NLRP3 pathway. These collectively galvanize innate as well as acquired immune responses and activate the complement system. Factors that have a profound influence on responses evoked by aluminum hydroxide-based adjuvant applications include adsorption rate, strength of the adsorption, size and uniformity of aluminum hydroxide particles, dosage of adjuvant, and the nature of antigens. Although vaccines containing aluminum hydroxide-based adjuvants are beneficial, sometimes they cause adverse reactions. Further, these vaccines cannot be stored frozen. Until recently, aluminum hydroxide-based adjuvants were known to preferentially prime Th2-type immune responses. However, results of more recent studies show that depending on the vaccination route, aluminum hydroxide-based adjuvants can enhance both Th1 as well as Th2 cellular responses. Advances in systems biology have opened up new avenues for studying mechanisms of aluminum hydroxide-based adjuvants. These will assist in scaling new frontiers in aluminum hydroxide-based adjuvant research that include improvement of formulations, use of nanoparticles of aluminum hydroxide and development of composite adjuvants. PMID:25692535

  3. Evaluation of layered zinc hydroxide nitrate and zinc/nickel double hydroxide salts in the removal of chromate ions from solutions

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bortolaz de Oliveira, Henrique; Wypych, Fernando, E-mail: wypych@ufpr.br

    Layered zinc hydroxide nitrate (ZnHN) and Zn/Ni layered double hydroxide salts were synthesized and used to remove chromate ions from solutions at pH 8.0. The materials were characterized by many instrumental techniques before and after chromate ion removal. ZnHN decomposed after contact with the chromate solution, whereas the layered structure of Zn/Ni hydroxide nitrate (Zn/NiHN) and Zn/Ni hydroxide acetate (Zn/NiHA) remained their layers intact after the topotactic anionic exchange reaction, only changing the basal distances. ZnHN, Zn/NiHN, and Zn/NiHA removed 210.1, 144.8, and 170.1 mg of CrO{sub 4}{sup 2−}/g of material, respectively. Although the removal values obtained for Zn/NiHN andmore » Zn/NiHA were smaller than the values predicted for the ideal formulas of the solids (194.3 and 192.4 mg of CrO{sub 4}{sup 2−}/g of material, respectively), the measured capacities were higher than the values achieved with many materials reported in the literature. Kinetic experiments showed the removal reaction was fast. To facilitate the solid/liquid separation process after chromium removal, Zn/Ni layered double hydroxide salts with magnetic supports were also synthesized, and their ability to remove chromate was evaluated. - Highlights: • Zinc hydroxide nitrate and Zn/Ni hydroxide nitrate or acetate were synthesized. • The interlayer anions were replaced by chromate anions at pH=8.0. • Only Zn/Ni hydroxide nitrate or acetate have the structure preserved after exchange. • Fast exchange reaction and high capacity of chromate removal were observed. • Magnetic materials were obtained to facilitate the solids removal the from solutions.« less

  4. Antimicrobial Activity of Calcium Hydroxide in Endodontics: A Review

    PubMed Central

    Shalavi, S; Yazdizadeh, M

    2012-01-01

    The purpose of endodontic therapy is to preserve the patient's natural teeth without compromising the patient's local or systemic health. Calcium hydroxide has been included in several materials and antimicrobial formulations that are used in several treatment modalities in endodontics, such as inter-appointment intracanal medicaments. The purpose of this article was to review the antimicrobial properties of calcium hydroxide in endodontics. Calcium hydroxide has a high pH (approximately 12.5-12.8) and is classified chemically as a strong base. The lethal effects of calcium hydroxide on bacterial cells are probably due to protein denaturation and damage to DNA and cytoplasmic membranes. Calcium hydroxide has a wide range of antimicrobial activity against common endodontic pathogens but is less effective against Enterococcus faecalis and Candida albicans. Calcium hydroxide is also a valuable anti-endotoxin agent. However, its effect on microbial biofilms is controversial. PMID:23323217

  5. Potassium hydroxide poisoning

    MedlinePlus

    ... effectively treat (adsorb) sodium hydroxide. For skin exposure, treatment may include: Surgical removal of burned skin (debridement) Transfer to a hospital that specializes in burn care Washing of the skin (irrigation), possibly every ...

  6. 40 CFR 721.10504 - Surface modified magnesium hydroxide (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Surface modified magnesium hydroxide... Specific Chemical Substances § 721.10504 Surface modified magnesium hydroxide (generic). (a) Chemical... as surface modified magnesium hydroxide (PMN P-06-682) is subject to reporting under this section for...

  7. 40 CFR 721.10504 - Surface modified magnesium hydroxide (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Surface modified magnesium hydroxide... Specific Chemical Substances § 721.10504 Surface modified magnesium hydroxide (generic). (a) Chemical... as surface modified magnesium hydroxide (PMN P-06-682) is subject to reporting under this section for...

  8. As-Received, Ozone Cleaned and Ar+ Sputtered Surfaces of Hafnium Oxide Grown by Atomic Layer Deposition and Studied by XPS

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Engelhard, Mark H.; Herman, Jacob A.; Wallace, Robert

    2012-06-27

    In this study, X-ray photoelectron spectroscopy (XPS) characterization was performed on 47 nm thick hafnium oxide (HfO{sub 2}) films grown by atomic layer deposition using TEMA-Hf/H{sub 2}O at 250 C substrate temperature. HfO{sub 2} is currently being studied as a possible replacement for Silicon Oxide (SiO{sub 2}) as a gate dielectric in electronics transistors. XPS spectra were collected on a Physical Electronics Quantum 2000 Scanning ESCA Microprobe using a monochromatic Al K{sub a} X-ray (1486.7 eV) excitation source. The sample was analyzed under the following conditions: as received, after UV irradiation for five minutes, and after sputter cleaning with 2more » kV Ar{sup +} ions for 180 seconds. Survey scans showed carbon, oxygen, and hafnium as the major species in the film, while the only minor species of argon and carbide was detected after sputtering. Adventitious carbon initially composed approximately 18.6 AT% of the surface, but after UV cleaning it was reduced to 2.4 AT%. This demonstrated that that the majority of carbon was due to adventitious carbon. However, after 2 kV Ar{sup +} sputtering there was still only trace amounts of carbon at {approx}1 AT%, Some of this trace carbon is now in the form of a carbide due to the interaction with Ar{sup +} used for sputter cleaning. Furthermore, the stoiciometric ratio of oxygen and hafnium is consistent with a high quality HfO{sub 2} film.« less

  9. Polysulfide intercalated layered double hydroxides for metal capture applications

    DOEpatents

    Kanatzidis, Mercouri G.; Ma, Shulan

    2017-04-04

    Polysulfide intercalated layered double hydroxides and methods for their use in vapor and liquid-phase metal capture applications are provided. The layered double hydroxides comprise a plurality of positively charged host layers of mixed metal hydroxides separated by interlayer spaces. Polysulfide anions are intercalated in the interlayer spaces.

  10. Hafnium, Tungsten, and the Differentiation of the Moon and Mars

    NASA Astrophysics Data System (ADS)

    Taylor, G. J.

    2003-11-01

    Measurements of the isotopic composition of tungsten (W) show that lunar samples and Martian meteorites have an excess of W-182. This was produced by the decay of hafnium-182 (Hf-182), an isotope with a half-life of only 9 million years. Because tungsten dissolves enthusiastically in metallic iron and hafnium does not, it is possible to use the abundance of W-182 in rocks formed by melting of the silicate mantle as an indicator of the timing of core formation. However, the concentrations of Hf and W in rocky material can be affected by melting and crystallization, so we also need to know how each element concentrates in common minerals in the mantles of the Moon and Mars. The behavior of Hf has been studied experimentally, but this is not true of W. Kevin Righter (Johnson Space Center) and Charles (Chip) Shearer (University of New Mexico) have filled this knowledge void by determining how W partitions between olivine, high- and low-calcium pyroxene, plagioclase feldspar, and garnet. The new data allowed Righter and Shearer to reexamine available measurements of the isotopic composition of W in lunar samples and Martian meteorites. Their analysis suggests that the lunar magma ocean, a huge magma system that surrounded the Moon when it formed, solidified in less than 30 million years. This is shorter than many theoretical calculations suggest. Pathfinder data and chemical data from Martian meteorites suggest that the core of Mars makes up about 20% of the planet. Core formation and subsequent melting of a region of the mantle containing garnet and high-calcium pyroxene took place less than 20-30 million years after the formation of the first solids in the solar system. This type of research shows the importance of measurements of isotopic compositions of radioactive elements or their decay products and laboratory experiments on the geochemical behavior of those elements.

  11. The alpha-form of the hydroxides of bivalent metals

    NASA Technical Reports Server (NTRS)

    Feitknecht, W.

    1984-01-01

    X-ray analyses were made of the hydroxides of the bivalent metals. The freshly pptd. hydroxide is usually in the alpha-form, which on standing is converted to another form or other forms. The alpha and c grating dimensions of the alpha-form and the C6-type of Co, Zn, C, Co-Zn and Ni-Zn hydroxides are tabulated. Ni hydroxide does not exhibit an alpha-form. The alpha-Co(OH)2, the blue form, is stabilized by sugar or by the higher alcohols: these compounds do not stabilize alpha-Zn(OH)2.

  12. Study of bulk Hafnium oxide (HfO2) under compression

    NASA Astrophysics Data System (ADS)

    Pathak, Santanu; Mandal, Guruprasad; Das, Parnika

    2018-04-01

    Hafnium oxide (HfO2) is a technologically important material. This material has K-value of 25 and band gap 5.8 eV. A k value of 25-30 is preferred for a gate dielectric [1]. As it shows good insulating and capacitive properties, HfO2 is being considered as a replacement to SiO2 in microelectronic devices as gate dielectrics. On the other hand because of toughening mechanism due to phase transformation induced by stress field observed in these oxides, HFO2 has been a material of investigations in various configurations for a very long time. However the controversies about phase transition of HfO2 under pressure still exists. High quality synchrotron radiation has been used to study the structural phase transition of HfO2 under pressure.

  13. Hydroxide-catalyzed bonding

    NASA Technical Reports Server (NTRS)

    Gwo, Dz-Hung (Inventor)

    2003-01-01

    A method of bonding substrates by hydroxide-catalyzed hydration/dehydration involves applying a bonding material to at least one surface to be bonded, and placing the at least one surface sufficiently close to another surface such that a bonding interface is formed between them. A bonding material of the invention comprises a source of hydroxide ions, and may optionally include a silicate component, a particulate filling material, and a property-modifying component. Bonding methods of the invention reliably and reproducibly provide bonds which are strong and precise, and which may be tailored according to a wide range of possible applications. Possible applications for bonding materials of the invention include: forming composite materials, coating substrates, forming laminate structures, assembly of precision optical components, and preparing objects of defined geometry and composition. Bonding materials and methods of preparing the same are also disclosed.

  14. Calcium hydroxide suppresses Porphyromonas endodontalis lipopolysaccharide-induced bone destruction.

    PubMed

    Guo, J; Yang, D; Okamura, H; Teramachi, J; Ochiai, K; Qiu, L; Haneji, T

    2014-05-01

    Porphyromonas endodontalis and its main virulence factor, lipopolysaccharide (LPS), are associated with the development of periapical diseases and alveolar bone loss. Calcium hydroxide is commonly used for endodontic therapy. However, the effects of calcium hydroxide on the virulence of P. endodontalis LPS and the mechanism of P. endodontalis LPS-induced bone destruction are not clear. Calcium hydroxide rescued the P. endodontalis LPS-suppressed viability of MC3T3-E1 cells and activity of nuclear factor-κB (NF-κB) in these cells, resulting in the reduced expression of interleukin-6 and tumor necrosis factor-α. In addition, calcium hydroxide inhibited P. endodontalis LPS-induced osteoclastogenesis by decreasing the activities of NF-κB, p38, and ERK1/2 and the expression of nuclear factor of activated T-cell cytoplasmic 1 in RAW264.7 cells. Calcium hydroxide also rescued the P. endodontalis LPS-induced osteoclastogenesis and bone destruction in mouse calvaria. Taken together, our present results indicate that calcium hydroxide suppressed bone destruction by attenuating the virulence of P. endodontalis LPS on bone cells.

  15. Multimode resistive switching in nanoscale hafnium oxide stack as studied by atomic force microscopy

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hou, Y., E-mail: houyi@pku.edu.cn, E-mail: lfliu@pku.edu.cn; IMEC, Kapeldreef 75, B-3001 Heverlee; Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, B-3001 Heverlee

    2016-07-11

    The nanoscale resistive switching in hafnium oxide stack is investigated by the conductive atomic force microscopy (C-AFM). The initial oxide stack is insulating and electrical stress from the C-AFM tip induces nanometric conductive filaments. Multimode resistive switching can be observed in consecutive operation cycles at one spot. The different modes are interpreted in the framework of a low defect quantum point contact theory. The model implies that the optimization of the conductive filament active region is crucial for the future application of nanoscale resistive switching devices.

  16. Composition effects on mechanical properties of tungsten-rhenium-hafnium-carbon alloys

    NASA Technical Reports Server (NTRS)

    Witzke, W. R.

    1973-01-01

    The mechanical properties of rod and sheet fabricated from arc melted W-4Re-Hf-C alloys containing up to about 0.8 mol percent hafnium carbide (HfC) were evaluated in the as-worked condition. The DBTT's of electropolished bend and tensile specimens were independent of HfC content in this range but dependent on excess Hf or C above that required for stoichiometric HfC. Low temperature ductility was a maximum at Hf contents slightly in excess of stoichiometric. Variations in high temperature strength were also dependent on excess Hf and C. Maximum creep strengthening also occurred at Hf contents in excess of stoichiometric. Analysis of extracted second phase particles indicated that creep strength was reduced by increasing WC content in the HfC particles.

  17. 21 CFR 73.1326 - Chromium hydroxide green.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Chromium hydroxide green. 73.1326 Section 73.1326 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1326 Chromium hydroxide green. (a) Identity. (1...

  18. 21 CFR 73.1326 - Chromium hydroxide green.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Chromium hydroxide green. 73.1326 Section 73.1326 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1326 Chromium hydroxide green. (a) Identity. (1...

  19. 21 CFR 73.1326 - Chromium hydroxide green.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Chromium hydroxide green. 73.1326 Section 73.1326 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1326 Chromium hydroxide green. (a) Identity. (1...

  20. Study of nickel hydroxide electrodes. 2: Oxidation products of nickel (2) hydroxides

    NASA Technical Reports Server (NTRS)

    Bode, H.; Demelt, K.; White, J.

    1986-01-01

    Pure phases of some oxidized Ni oxides were prepared galvanimetrically with the Ni(2) hydroxide electrode of an alkaline battery. The crystallographic data of these phases, their chemical behavior, and conditions of transition were studied.

  1. Evaluation of layered zinc hydroxide nitrate and zinc/nickel double hydroxide salts in the removal of chromate ions from solutions

    NASA Astrophysics Data System (ADS)

    de Oliveira, Henrique Bortolaz; Wypych, Fernando

    2016-11-01

    Layered zinc hydroxide nitrate (ZnHN) and Zn/Ni layered double hydroxide salts were synthesized and used to remove chromate ions from solutions at pH 8.0. The materials were characterized by many instrumental techniques before and after chromate ion removal. ZnHN decomposed after contact with the chromate solution, whereas the layered structure of Zn/Ni hydroxide nitrate (Zn/NiHN) and Zn/Ni hydroxide acetate (Zn/NiHA) remained their layers intact after the topotactic anionic exchange reaction, only changing the basal distances. ZnHN, Zn/NiHN, and Zn/NiHA removed 210.1, 144.8, and 170.1 mg of CrO42-/g of material, respectively. Although the removal values obtained for Zn/NiHN and Zn/NiHA were smaller than the values predicted for the ideal formulas of the solids (194.3 and 192.4 mg of CrO42-/g of material, respectively), the measured capacities were higher than the values achieved with many materials reported in the literature. Kinetic experiments showed the removal reaction was fast. To facilitate the solid/liquid separation process after chromium removal, Zn/Ni layered double hydroxide salts with magnetic supports were also synthesized, and their ability to remove chromate was evaluated.

  2. Cu2+ ions as a paramagnetic probe to study the surface chemical modification process of layered double hydroxides and hydroxide salts with nitrate and carboxylate anions.

    PubMed

    Arizaga, Gregorio Guadalupe Carbajal; Mangrich, Antonio Salvio; Wypych, Fernando

    2008-04-01

    A layered zinc hydroxide nitrate (Zn5(OH)8(NO3)2.2H2O) and a layered double hydroxide (Zn/Al-NO3) were synthesized by coprecipitation and doped with different amounts of Cu2+ (0.2, 1, and 10 mol%), as paramagnetic probe. Although the literature reports that the nitrate ion is free (with D3h symmetry) between the layers of these two structures, the FTIR spectra of two zinc hydroxide nitrate samples show the C2v symmetry for the nitrate ion, whereas the g ||/A || value in the EPR spectra of Cu2+ is high. This fact suggests bonding of some nitrate ions to the layers of the zinc hydroxide nitrate. The zinc hydroxide nitrate was used as matrix in the intercalation reaction with benzoate, o-chlorobenzoate, and o-iodobenzoate ions. FTIR spectra confirm the ionic exchange reaction and the EPR spectroscopy reveals bonding of the organic ions to the inorganic layers of the zinc hydroxide nitrate, while the layered double hydroxides show only exchange reactions.

  3. Conversion coatings prepared or treated with calcium hydroxide solutions

    NASA Technical Reports Server (NTRS)

    Maxey, Jason (Inventor); Nelson, Carl (Inventor); Eylem, Cahit (Inventor); Minevski, Zoran (Inventor); Clarke, Eric (Inventor)

    2002-01-01

    A conversion coating process that forms a stable and corrosion-resistant oxide layer on metal or metal oxide substrates or layers. Particularly, the conversion coating process involves contacting the metal or metal oxide substrate or layer with the aqueous calcium hydroxide solutions in order to convert the surface of the substrate to a stable metal oxide layer or coating. According to the present invention, the calcium hydroxide solution is prepared by removing carbon dioxide from water or an aqueous solution before introducing the calcium hydroxide. In this manner, formation of calcium carbonate particles is avoided and the porosity of the conversion coating produced by the calcium hydroxide solution is reduced to below about 1%.

  4. Intercalation studies of zinc hydroxide chloride: Ammonia and amino acids

    NASA Astrophysics Data System (ADS)

    Arízaga, Gregorio Guadalupe Carbajal

    2012-01-01

    Zinc hydroxide chloride (ZHC) is a layered hydroxide salt with formula Zn5(OH)8Cl2·2H2O. It was tested as intercalation matrix for the first time and results were compared with intercalation products of the well-known zinc hydroxide nitrate and a Zn/Al layered double hydroxide. Ammonia was intercalated into ZHC, while no significant intercalation occurred in ZHN. Aspartic acid intercalation was only achieved by co-precipitation at pH=10 with ZHC and pH=8 with zinc hydroxide nitrate. Higher pH resistance in ZHC favored total deprotonation of both carboxylic groups of the Asp molecule. ZHC conferred more thermal protection against Asp combustion presenting exothermic peaks even at 452 °C while the exothermic event in ZHN was 366 °C and in the LDH at 276 °C.

  5. 21 CFR 73.1010 - Alumina (dried aluminum hydroxide).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Alumina (dried aluminum hydroxide). 73.1010 Section 73.1010 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES...) Specifications. Alumina (dried aluminum hydroxide) shall conform to the following specifications: Acidity or...

  6. Antimicrobial activity of calcium hydroxide and chlorhexidine on intratubular Candida albicans

    PubMed Central

    Jacques Rezende Delgado, Ronan; Helena Gasparoto, Thaís; Renata Sipert, Carla; Ramos Pinheiro, Claudia; Gomes de Moraes, Ivaldo; Brandão Garcia, Roberto; Antônio Hungaro Duarte, Marco; Monteiro Bramante, Clóvis; Aparecido Torres, Sérgio; Pompermaier Garlet, Gustavo; Paula Campanelli, Ana; Bernardineli, Norberti

    2013-01-01

    This study investigated the efficacy of calcium hydroxide and chlorhexidine gel for the elimination of intratubular Candida albicans (C. albicans). Human single-rooted teeth contaminated with C. albicans were treated with calcium hydroxide, 2% chlorhexidine gel, calcium hydroxide plus 2% chlorhexidine gel, or saline (0.9% sodium chloride) as a positive control. The samples obtained at depths of 0–100 and 100–200 µm from the root canal system were analyzed for C. albicans load by counting the number of colony forming units and for the percentage of viable C. albicans using fluorescence microscopy. First, the antimicrobial activity of calcium hydroxide and the 2% chlorhexidine gel was evaluated by counting the number of colony forming units. After 14 days of intracanal medication, there was a significant decrease in the number of C. albicans colony forming units at a depth of 0–100 µm with chlorhexidine treatment either with or without calcium hydroxide compared with the calcium hydroxide only treatment. However, there were no differences in the number of colony forming units at the 100–200 µm depth for any of the medications investigated. C. albicans viability was also evaluated by vital staining techniques and fluorescence microscopy analysis. Antifungal activity against C. albicans significantly increased at both depths in the chlorhexidine groups with and without calcium hydroxide compared with the groups treated with calcium hydroxide only. Treatments with only chlorhexidine or chlorhexidine in combination with calcium hydroxide were effective for elimination of C. albicans. PMID:23538639

  7. Chemical matricectomy with sodium hydroxide: long-term follow-up results.

    PubMed

    Bostanci, Seher; Kocyigit, Pelin; Parlak, Nehir; Gungor, Hilayda Karakok

    2014-11-01

    Chemical matricectomy with sodium hydroxide is a method being used successfully in the treatment of ingrown toenail. In this study, it was aimed to evaluate long-term recurrence rates after chemical matricectomy using sodium hydroxide application of different durations. Two hundred two patients with ingrown nail edges were treated with either 1-minute (Group 1) or 2-minute (Group 2) applications of sodium hydroxide matricectomy. All patients were followed for at least 2 years. Chemical matricectomy with sodium hydroxide was applied to a total of 585 nail edges of 202 cases. The overall recurrence rates in Group 1 and Group 2 were 6.4% and 7.1%, respectively, during the average 7.5-year follow-up period. No statistically significant differences were detected in terms of recurrence between the 2 groups (p = .73). Chemical matricectomy with sodium hydroxide is an easy method in the treatment of ingrown nails, with low morbidity and high success rates. There was no difference between 1-minute and 2-minute applications in terms of recurrence during the long-term follow-up. Chemical matricectomy with 1-minute application of sodium hydroxide showed high success in terms of long-term follow-up results.

  8. Aspects of Solvent Chemistry for Calcium Hydroxide Medicaments

    PubMed Central

    Athanassiadis, Basil

    2017-01-01

    Calcium hydroxide pastes have been used in endodontics since 1947. Most current calcium hydroxide endodontic pastes use water as the vehicle, which limits the dissolution of calcium hydroxide that can be achieved and, thereby, the maximum pH that can be achieved within the root canal system. Using polyethylene glycol as a solvent, rather than water, can achieve an increase in hydroxyl ions release compared to water or saline. By adopting non-aqueous solvents such as the polyethylene glycols (PEG), greater dissolution and faster hydroxyl ion release can be achieved, leading to enhanced antimicrobial actions, and other improvements in performance and biocompatibility. PMID:29065542

  9. Pyroelectricity of silicon-doped hafnium oxide thin films

    NASA Astrophysics Data System (ADS)

    Jachalke, Sven; Schenk, Tony; Park, Min Hyuk; Schroeder, Uwe; Mikolajick, Thomas; Stöcker, Hartmut; Mehner, Erik; Meyer, Dirk C.

    2018-04-01

    Ferroelectricity in hafnium oxide thin films is known to be induced by various doping elements and in solid-solution with zirconia. While a wealth of studies is focused on their basic ferroelectric properties and memory applications, thorough studies of the related pyroelectric properties and their application potential are only rarely found. This work investigates the impact of Si doping on the phase composition and ferro- as well as pyroelectric properties of thin film capacitors. Dynamic hysteresis measurements and the field-free Sharp-Garn method were used to correlate the reported orthorhombic phase fractions with the remanent polarization and pyroelectric coefficient. Maximum values of 8.21 µC cm-2 and -46.2 µC K-1 m-2 for remanent polarization and pyroelectric coefficient were found for a Si content of 2.0 at%, respectively. Moreover, temperature-dependent measurements reveal nearly constant values for the pyroelectric coefficient and remanent polarization over the temperature range of 0 ° C to 170 ° C , which make the material a promising candidate for IR sensor and energy conversion applications beyond the commonly discussed use in memory applications.

  10. Lifetime of Sodium Beta-Alumina Membranes in Molten Sodium Hydroxide

    DTIC Science & Technology

    2008-07-01

    ABSTRACT Summary: Sodium metal can be made by electrolysis of molten sodium hydroxide in sodium beta-alumina membrane electrolysis cells... electrolysis of molten sodium hydroxide in sodium ”-alumina membrane electrolysis cells. However, there are some uncertainties about the lifetime of the...the properties of the membrane degrade upon long term contact with molten sodium hydroxide. Electrolysis cells were designed, but it proved

  11. Nickel hydroxide/cobalt-ferrite magnetic nanocatalyst for alcohol oxidation.

    PubMed

    Bhat, Pooja B; Inam, Fawad; Bhat, Badekai Ramachandra

    2014-08-11

    A magnetically separable, active nickel hydroxide (Brønsted base) coated nanocobalt ferrite catalyst has been developed for oxidation of alcohols. High surface area was achieved by tuning the particle size with surfactant. The surface area of 120.94 m2 g(-1) has been achieved for the coated nanocobalt ferrite. Improved catalytic activity and selectivity were obtained by synergistic effect of transition metal hydroxide (basic hydroxide) on nanocobalt ferrite. The nanocatalyst oxidizes primary and secondary alcohols efficiently (87%) to corresponding carbonyls in good yields.

  12. Zirconium and hafnium fractionation in differentiation of alkali carbonatite magmatic systems

    NASA Astrophysics Data System (ADS)

    Kogarko, L. N.

    2016-05-01

    Zirconium and hafnium are valuable strategic metals which are in high demand in industry. The Zr and Hf contents are elevated in the final products of magmatic differentiation of alkali carbonatite rocks in the Polar Siberia region (Guli Complex) and Ukraine (Chernigov Massif). Early pyroxene fractionation led to an increase in the Zr/Hf ratio in the evolution of the ultramafic-alkali magmatic system due to a higher distribution coefficient of Hf in pyroxene with respect to Zr. The Rayleigh equation was used to calculate a quantitative model of variation in the Zr/Hf ratio in the development of the Guli magmatic system. Alkali carbonatite rocks originated from rare element-rich mantle reservoirs, in particular, the metasomatized mantle. Carbonated mantle xenoliths are characterized by a high Zr/Hf ratio due to clinopyroxene development during metasomatic replacement of orthopyroxene by carbonate fluid melt.

  13. Experimental and first-principles studies on the elastic properties of α-hafnium metal under pressure

    DOE PAGES

    Qi, Xintong; Wang, Xuebing; Chen, Ting; ...

    2016-03-30

    Compressional and shear wave velocities of the α phase of hafnium have been measured up to 10.4 GPa at room temperature using ultrasonic interferometry in a multi-anvil apparatus. A finite strain equation of state analysis yielded K s0 = 110.4 (5) GPa, G 0 = 54.7(5) GPa,K s0' = 3.7 and G 0' = 0.6 for the elastic bulk and shear moduli and their pressure derivatives at ambient conditions. Complementary to the experimental data, the single crystal elastic constants, elastic anisotropy and the unit cell axial ratio c/a of α-hafnium at high pressures were investigated by Density Functional Theory (DFT)more » based first principles calculations. A c/a value of 1.605 is predicted for α-Hf at 40 GPa, which is in excellent agreement with previous experimental results. The low-pressure derivative of the shear modulus observed in our experimental data up to 10 GPa was found to originate from the elastic constant C44 which exhibits negligible pressure dependence within the current experimental pressure range. At higher pressures (>10 GPa), C 44 was predicted to soften and the shear wave velocity ν S trended to decrease with pressure, which can be interpreted as a precursor to the α-ω transition similar to that observed in other group IV elements (titanium and zirconium). Here, the acoustic velocities, bulk and shear moduli, and the acoustic Debye temperature (θ D = 240.1 K) determined from the current experiments were all compared well with those predicted by our theoretical DFT calculations.« less

  14. Stress-rupture strength and microstructural stability of tungsten-hafnium-carbon-wire reinforced superalloy composites

    NASA Technical Reports Server (NTRS)

    Petrasek, D. W.; Signorelli, R. A.

    1974-01-01

    Tungsten-hafnium-carbon - superalloy composites were found to be potentially useful for turbine blade applications on the basis of stress-rupture strength. The 100- and 1000-hr rupture strengths calculated for 70 vol. % fiber composites based on test data at 1090C (2000F) were 420 and 280 MN/m2 (61,000 and 41,000 psi, respectively). The investigation indicated that, with better quality fibers, composites having 100- and 1000-hr rupture strengths of 570 and 370 MN/m2 (82,000 and 54,000 psi, respectively), may be obtained. Metallographic studies indicated sufficient fiber-matrix compatibility for 1000 hr or more at 1090C (2000F).

  15. 40 CFR 415.310 - Applicability; description of the calcium hydroxide production subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... calcium hydroxide production subcategory. 415.310 Section 415.310 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Calcium Hydroxide Production Subcategory § 415.310 Applicability; description of the calcium hydroxide production subcategory. The provisions of this subpart are applicable to discharges...

  16. 40 CFR 415.310 - Applicability; description of the calcium hydroxide production subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... calcium hydroxide production subcategory. 415.310 Section 415.310 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Calcium Hydroxide Production Subcategory § 415.310 Applicability; description of the calcium hydroxide production subcategory. The provisions of this subpart are applicable to discharges...

  17. 40 CFR 415.310 - Applicability; description of the calcium hydroxide production subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... calcium hydroxide production subcategory. 415.310 Section 415.310 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Calcium Hydroxide Production Subcategory § 415.310 Applicability; description of the calcium hydroxide production subcategory. The provisions of this subpart are applicable to discharges...

  18. 40 CFR 415.310 - Applicability; description of the calcium hydroxide production subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... calcium hydroxide production subcategory. 415.310 Section 415.310 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Calcium Hydroxide Production Subcategory § 415.310 Applicability; description of the calcium hydroxide production subcategory. The provisions of this subpart are applicable to discharges...

  19. 40 CFR 415.310 - Applicability; description of the calcium hydroxide production subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... calcium hydroxide production subcategory. 415.310 Section 415.310 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Calcium Hydroxide Production Subcategory § 415.310 Applicability; description of the calcium hydroxide production subcategory. The provisions of this subpart are applicable to discharges...

  20. Neutralization of Hydroxide Ion in Melt-Grown NaCl Crystals

    NASA Technical Reports Server (NTRS)

    Otterson, Dumas A.

    1961-01-01

    Many recent studies of solid-state phenomena, particularly in the area of crystal imperfections, have involved the use of melt-grown NaCl single crystals. Quite often trace impurities in these materials have had a prominent effect on these phenomena. Trace amounts of hydroxide ion have been found in melt-grown NaCl crystals. This paper describes a nondestructive method of neutralizing the hydroxide ion in such crystals. Crystals of similar hydroxide content are maintained at an elevated temperature below the melting point of NaCl in a flowing atmosphere containing. dry hydrogen chloride. Heat treatment is continued until an analysis of the test specimens shows no excess hydroxide ion. A colorimetric method previously described4 is used for this analysis.

  1. 40 CFR 721.10573 - Magnesium hydroxide surface treated with substituted alkoxysilanes (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Magnesium hydroxide surface treated... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10573 Magnesium hydroxide surface... to reporting. (1) The chemical substance identified generically as magnesium hydroxide surface...

  2. 40 CFR 721.10573 - Magnesium hydroxide surface treated with substituted alkoxysilanes (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Magnesium hydroxide surface treated... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10573 Magnesium hydroxide surface... to reporting. (1) The chemical substance identified generically as magnesium hydroxide surface...

  3. Silicon doped hafnium oxide (HSO) and hafnium zirconium oxide (HZO) based FeFET: A material relation to device physics

    NASA Astrophysics Data System (ADS)

    Ali, T.; Polakowski, P.; Riedel, S.; Büttner, T.; Kämpfe, T.; Rudolph, M.; Pätzold, B.; Seidel, K.; Löhr, D.; Hoffmann, R.; Czernohorsky, M.; Kühnel, K.; Thrun, X.; Hanisch, N.; Steinke, P.; Calvo, J.; Müller, J.

    2018-05-01

    The recent discovery of ferroelectricity in thin film HfO2 materials renewed the interest in ferroelectric FET (FeFET) as an emerging nonvolatile memory providing a potential high speed and low power Flash alternative. Here, we report more insight into FeFET performance by integrating two types of ferroelectric (FE) materials and varying their properties. By varying the material type [HfO2 (HSO) versus hafnium zirconium oxide (HZO)], optimum content (Si doping/mixture ratio), and film thickness, a material relation to FeFET device physics is concluded. As for the material type, an improved FeFET performance is observed for HZO integration with memory window (MW) comparable to theoretical values. For different Si contents, the HSO based FeFET exhibited a MW trend with different stabilized phases. Similarly, the HZO FeFET shows MW dependence on the Hf:Zr mixture ratio. A maximized MW is obtained with cycle ratios of 16:1 (HfO2:Si) and 1:1 (Hf:Zr) as measured on HSO and HZO based FeFETs, respectively. The thickness variation shows a trend of increasing MW with the increased FE layer thickness confirming early theoretical predictions. The FeFET material aspects and stack physics are discussed with insight into the interplay factors, while optimum FE material parameters are outlined in relation to performance.

  4. DOUBLE SHELL TANK (DST) HYDROXIDE DEPLETION MODEL FOR CARBON DIOXIDE ABSORPTION

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    OGDEN DM; KIRCH NW

    2007-10-31

    This document generates a supernatant hydroxide ion depletion model based on mechanistic principles. The carbon dioxide absorption mechanistic model is developed in this report. The report also benchmarks the model against historical tank supernatant hydroxide data and vapor space carbon dioxide data. A comparison of the newly generated mechanistic model with previously applied empirical hydroxide depletion equations is also performed.

  5. Effect of ammonium hydroxide on ultrastructure and tenderness of buffalo meat.

    PubMed

    Naveena, B M; Kiran, M; Reddy, K Sudhakar; Ramakrishna, C; Vaithiyanathan, S; Devatkal, Suresh K

    2011-08-01

    This study was conducted with an objective to improve the tenderness of tough buffalo meat using ammonium hydroxide. Buffalo meat chunks from Biceps femoris muscle were marinated with distilled water (control), 0.1%, 0.5% and 1.0% solution of ammonium hydroxide for 48 h at 4±1 °C and subjected to various physico-chemical analysis and ultrastructural studies. Ammonium hydroxide increased (P<0.05) the pH, water holding capacity (WHC), collagen solubility, total and salt soluble protein extractability and cooking yield. Reduction (P<0.05) in Warner-Bratzler shear force values were observed in all ammonium hydroxide treated samples compared to non-treated control. Electrophoretic pattern of muscle proteins exhibited reduction in the intensity and number of certain protein bands for 0.1% and 0.5% ammonium hydroxide treated samples compared to control. Scanning and transmission electron microscopy also revealed breakdown of endothelium layers surrounding muscle fibers and weakening of Z-discs respectively, in treated samples compared to controls. These results suggest that ammonium hydroxide might be used to tenderize tough buffalo meat. Copyright © 2011 Elsevier Ltd. All rights reserved.

  6. Atomic layer deposition of hafnium oxide: A detailed reaction mechanism from first principles

    NASA Astrophysics Data System (ADS)

    Widjaja, Yuniarto; Musgrave, Charles B.

    2002-08-01

    Atomic layer deposition (ALD) of hafnium oxide (HfO2) using HfCl4 and H2O as precursors is studied using density functional theory. The mechanism consists of two deposition half-reactions: (1) HfCl4 with Hf-OH sites, and (2) H2O with Hf-Cl sites. Both half-reactions exhibit stable intermediates with energies lower than those of the final products. We show that increasing the temperature reduces the stability of the complex. However, increasing temperature also increases the dissociation free-energy barrier, which in turn results in increased desorption of adsorbed precursors. Both half-reactions are qualitatively similar to the corresponding reactions of ZrO2 ALD using ZrCl4 and H2O.

  7. Intrinsic Defect Ferromagnetism: The case of Hafnium Oxide

    NASA Astrophysics Data System (ADS)

    Das Pemmaraju, Chaitanya

    2005-03-01

    In view of the recent experimental reports of intrinsic ferromagnetism in Hafnium Oxide (HfO2) thin film systems ootnotetextM. Venkatesan, C. B. Fitzgerald, J. M. D. Coey Nature 430, 630 (2004) Brief Communications, we carried out first principles investigations to look for magnetic structure in HfO2 possibly brought about by the presence of small concentrations of intrinsic point defects. Ab initio electronic structure calculations using Density Functional Theory (DFT) show that isolated cation vacancy sites in HfO2 lead to the formation of high spin defect states which couple ferromagnetically to each other. Interestingly, these high spin states are observed in the low symmetry monoclinic and tetragonal phases while the highly symmetric cubic flourite phase exhibits a non-magnetic ground state. Detailed studies of the electronic structure of cation vacancies in the three crystalline phases of Hafnia show that symmetry leading to orbitally degenerate defect levels is not a pre-requsite for ferromagnetism and that the interplay between Kinetic, Coulomb and Exchange energy together with favourable coupling to the Crystalline environment can lead to high spin ferromagnetic ground states even in extreme low symmetry systems like monoclinic HfO2. These findings open up a much wider class of systems to the possibility of intrinsic defect ferromagnetism.

  8. Work functions of hafnium nitride thin films as emitter material for field emitter arrays

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gotoh, Yasuhito, E-mail: gotoh.yasuhito.5w@kyoto-u.ac.jp; Fujiwara, Sho; Tsuji, Hiroshi

    The work functions of hafnium nitride thin films prepared by radio-frequency magnetron sputtering were investigated in vacuum, before and after surface cleaning processes, with a view of improving the properties of as-fabricated field emitter arrays comprising hafnium nitride emitters. The measurement of the work function was first performed for the as-deposited films and then for films subjected to surface cleaning process, either thermal treatment or ion bombardment. Thermal treatment at a maximum temperature of 300 °C reduced the work function by 0.7 eV. Once the film was heated, the work function maintained the reduced value, even after cooling to room temperature. Amore » little change in the work function was observed for the second and third thermal treatments. The ion bombardment was conducted by exposing the sample to a thin plasma for different sample bias conditions and processing times. When the sample was biased at −10 V, the work function decreased by 0.6 eV. The work function reduction became saturated in the early stage of the ion bombardment. When the sample was biased at −50 V, the work function exhibited different behaviors, that is, first it decreased rapidly and then increased in response to the increase in processing time. The lowest attainable work function was found to be 4.00 eV. It should be noted that none of the work function values reported in this paper were obtained using surfaces that were demonstrated to be free from oxygen contamination. The present results suggest that the current–voltage characteristics of a field emitter array can be improved by a factor of 25–50 by the examined postprocesses.« less

  9. The interfacial orientation relationship of oxide nanoparticles in a hafnium-containing oxide dispersion-strengthened austenitic stainless steel

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Miao, Yinbin, E-mail: miao2@illinois.edu; Mo, Kun; Cui, Bai

    2015-03-15

    This work reports comprehensive investigations on the orientation relationship of the oxide nanoparticles in a hafnium-containing austenitic oxide dispersion-strengthened 316 stainless steel. The phases of the oxide nanoparticles were determined by a combination of scanning transmission electron microscopy–electron dispersive X-ray spectroscopy, atom probe tomography and synchrotron X-ray diffraction to be complex Y–Ti–Hf–O compounds with similar crystal structures, including bixbyite Y{sub 2}O{sub 3}, fluorite Y{sub 2}O{sub 3}–HfO{sub 2} solid solution and pyrochlore (or fluorite) Y{sub 2}(Ti,Hf){sub 2−x}O{sub 7−x}. High resolution transmission electron microscopy was used to characterize the particle–matrix interfaces. Two different coherency relationships along with one axis-parallel relation between themore » oxide nanoparticles and the steel matrix were found. The size of the nanoparticles significantly influences the orientation relationship. The results provide insight into the relationship of these nanoparticles with the matrix, which has implications for interpreting material properties as well as responses to radiation. - Highlights: • The oxide nanoparticles in a hafnium-containing austenitic ODS were characterized. • The nanoparticles are Y–Hf–Ti–O enriched phases according to APT and STEM–EDS. • Two coherency and an axis-parallel orientation relationships were found by HR-TEM. • Particle size has a prominent effect on the orientation relationship (OR). • Formation mechanism of the oxide nanoparticles was discussed based on the ORs.« less

  10. Complications of sodium hydroxide chemical matrixectomy: nail dystrophy, allodynia, hyperalgesia.

    PubMed

    Bostancı, Seher; Koçyiğit, Pelin; Güngör, Hilayda Karakök; Parlak, Nehir

    2014-11-01

    Ingrown toenails are seen most commonly in young adults, and they can seriously affect daily life. Partial nail avulsion with chemical matrixectomy, generally by using either sodium hydroxide or phenol, is one of the most effective treatment methods. Known complications of phenol matrixectomy are unpredictable tissue damage, prolonged postoperative drainage, increased secondary infection rates, periostitis, and poor cosmetic results. To our knowledge, there have been no reports about the complications related to sodium hydroxide matrixectomy. Herein, we describe three patients who developed nail dystrophy, allodynia, and hyperalgesia after sodium hydroxide matrixectomy.

  11. Method of manufacturing positive nickel hydroxide electrodes

    DOEpatents

    Gutjahr, M.A.; Schmid, R.; Beccu, K.D.

    1975-12-16

    A method of manufacturing a positive nickel hydroxide electrode is discussed. A highly porous core structure of organic material having a fibrous or reticular texture is uniformly coated with nickel powder and then subjected to a thermal treatment which provides sintering of the powder coating and removal of the organic core material. A consolidated, porous nickel support structure is thus produced which has substantially the same texture and porosity as the initial core structure. To provide the positive electrode including the active mass, nickel hydroxide is deposited in the pores of the nickel support structure.

  12. Hydroxide catalysts for lignin depolymerization

    DOEpatents

    Beckham, Gregg T; Biddy, Mary J.; Kruger, Jacob S.; Chmely, Stephen C.; Sturgeon, Matthew

    2017-10-17

    Solid base catalysts and their use for the base-catalyzed depolymerization (BCD) of lignin to compounds such as aromatics are presented herein. Exemplary catalysts include layered double hydroxides (LDHs) as recyclable, heterogeneous catalysts for BCD of lignin.

  13. Hydroxide catalysts for lignin depolymerization

    DOEpatents

    Beckham, Gregg T.; Biddy, Mary J.; Chmely, Stephen C.; Sturgeon, Matthew

    2017-04-25

    Solid base catalysts and their use for the base-catalyzed depolymerization (BCD) of lignin to compounds such as aromatics are presented herein. Exemplary catalysts include layered double hydroxides (LDHs) as recyclable, heterogeneous catalysts for BCD of lignin.

  14. Tailoring the index of refraction of nanocrystalline hafnium oxide thin films

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Vargas, Mirella; Murphy, N. R.; Ramana, C. V., E-mail: rvchintalapalle@utep.edu

    2014-03-10

    Hafnium oxide (HfO{sub 2}) films were grown by sputter-deposition by varying the growth temperature (T{sub s} = 25–700 °C). HfO{sub 2} films grown at T{sub s} < 200 °C were amorphous, while those grown at T{sub s} ≥ 200 °C were monoclinic, nanocrystalline with (1{sup ¯}11) texturing. X-ray reflectivity (XRR) analyses indicate that the film-density (ρ) increases with increasing T{sub s}. The index of refraction (n) profiles derived from spectroscopic ellipsometry analyses follow the Cauchy dispersion relation. Lorentz-Lorenz analysis (n{sub (λ)} = 550 nm) and optical-model adopted agree well with the XRR data/analyses. A direct T{sub s}-ρ-n relationship suggests that tailoring the optical quality is possible by tuning T{sub s} and themore » microstructure of HfO{sub 2} films.« less

  15. Method of treating inflammatory diseases using a radiolabeled ferric hydroxide calloid

    DOEpatents

    Atcher, Robert W.; Hines, John J.

    1992-01-01

    A ferric hydroxide colloid having an alpha-emitting radionuclide essentially on the outer surfaces and a method of forming same. The method includes oxidizing a ferrous hydroxide to ferric hydroxide in the presence of a preselected radionuclide to form a colloid having the radionuclide on the outer surface thereof, and thereafter washing the colloid, and suspending the washed colloid in a suitable solution. The labelled colloid is useful in cancer therapy and for the treatment of inflamed joints.

  16. Rapeseed-straw enzymatic digestibility enhancement by sodium hydroxide treatment under ultrasound irradiation.

    PubMed

    Kang, Kyeong Eop; Jeong, Gwi-Taek; Park, Don-Hee

    2013-08-01

    In this study, we carried out sodium hydroxide and sonication pretreatments of rapeseed straw (Brassica napus) to obtain monosugar suitable for production of biofuels. To optimize the pretreatment conditions, we applied a statistical response-surface methodology. The optimal pretreatment conditions using sodium hydroxide under sonication irradiation were determined to be 75.0 °C, 7.0 % sodium hydroxide, and 6.8 h. For these conditions, we predicted 97.3 % enzymatic digestibility. In repeated experiments to validate the predicted value, 98.9 ± 0.3 % enzymatic digestibility was obtained, which was well within the range of the predicted model. Moreover, sonication irradiation was found to have a good effect on pretreatment in the lower temperature range and at all concentrations of sodium hydroxide. According to scanning electron microscopy images, the surface area and pore size of the pretreated rapeseed straw were modified by the sodium hydroxide pretreatment under sonication irradiation.

  17. Controllable synthesis of layered Co-Ni hydroxide hierarchical structures for high-performance hybrid supercapacitors

    NASA Astrophysics Data System (ADS)

    Yuan, Peng; Zhang, Ning; Zhang, Dan; Liu, Tao; Chen, Limiao; Ma, Renzhi; Qiu, Guanzhou; Liu, Xiaohe

    2016-01-01

    A facile solvothermal method is developed for synthesizing layered Co-Ni hydroxide hierarchical structures by using hexamethylenetetramine (HMT) as alkaline reagent. The electrochemical measurements reveal that the specific capacitances of layered bimetallic (Co-Ni) hydroxides are generally superior to those of layered monometallic (Co, Ni) hydroxides. The as-prepared Co0.5Ni0.5 hydroxide hierarchical structures possesses the highest specific capacitance of 1767 F g-1 at a galvanic current density of 1 A g-1 and an outstanding specific capacitance retention of 87% after 1000 cycles. In comparison with the dispersed nanosheets of Co-Ni hydroxide, layered hydroxide hierarchical structures show much superior electrochemical performance. This study provides a promising method to construct hierarchical structures with controllable transition-metal compositions for enhancing the electrochemical performance in hybrid supercapacitors.

  18. Synthesis of high capacity cathodes for lithium-ion batteries by morphology-tailored hydroxide co-precipitation

    NASA Astrophysics Data System (ADS)

    Wang, Dapeng; Belharouak, Ilias; Ortega, Luis H.; Zhang, Xiaofeng; Xu, Rui; Zhou, Dehua; Zhou, Guangwen; Amine, Khalil

    2015-01-01

    Nickel manganese hydroxide co-precipitation inside a continuous stirred tank reactor was studied with sodium hydroxide and ammonium hydroxide as the precipitation agents. The ammonium hydroxide concentration had an effect on the primary and secondary particle evolution. The two-step precipitation mechanism proposed earlier was experimentally confirmed. In cell tests, Li- and Mn-rich composite cathode materials based on the hydroxide precursors demonstrated good electrochemical performance in terms of cycle life over a wide range of lithium content.

  19. Hafnium-doped hydroxyapatite nanoparticles with ionizing radiation for lung cancer treatment.

    PubMed

    Chen, Min-Hua; Hanagata, Nobutaka; Ikoma, Toshiyuki; Huang, Jian-Yuan; Li, Keng-Yuan; Lin, Chun-Pin; Lin, Feng-Huei

    2016-06-01

    Recently, photodynamic therapy (PDT) is one of the new clinical options by generating cytotoxic reactive oxygen species (ROS) to kill cancer cells. However, the optical approach of PDT is limited by tissue penetration depth of visible light. In this study, we propose that a ROS-enhanced nanoparticle, hafnium-doped hydroxyapatite (Hf:HAp), which is a material to yield large quantities of ROS inside the cells when the nanoparticles are bombarded with high penetrating power of ionizing radiation. Hf:HAp nanoparticles are generated by wet chemical precipitation with total doping concentration of 15mol% Hf(4+) relative to Ca(2+) in HAp host material. The results show that the HAp particles could be successfully doped with Hf ions, resulted in the formation of nano-sized rod-like shape and with pH-dependent solubility. The impact of ionizing radiation on Hf:HAp nanoparticles is assessed by using in-vitro and in-vivo model using A549 cell line. The 2',7'-dichlorofluorescein diacetate (DCFH-DA) results reveal that after being exposed to gamma rays, Hf:HAp could significantly lead to the formation of ROS in cells. Both cell viability (WST-1) and cytotoxicity (LDH) assay show the consistent results that A549 lung cancer cell lines are damaged with changes in the cells' ROS level. The in-vivo studies further demonstrate that the tumor growth is inhibited owing to the cells apoptosis when Hf:HAp nanoparticles are bombarded with ionizing radiation. This finding offer a new therapeutic method of interacting with ionizing radiation and demonstrate the potential of Hf:HAp nanoparticles in tumor treatment, such as being used in a palliative treatment after lung surgical procedure. Photodynamic therapy (PDT) is one of the new clinical options by generating cytotoxic reactive oxygen species (ROS) to kill cancer cells. Unfortunately, the approach of PDT is usually limited to the treatment of systemic disease and deeper tumor, due to the limited tissue penetration depth of visible

  20. Comparison of phenol and sodium hydroxide chemical matricectomies for the treatment of ingrowing toenails.

    PubMed

    Bostanci, Seher; Kocyigit, Pelin; Gürgey, Erbak

    2007-06-01

    Chemical matricectomy is performed mainly by two agents: phenol and sodium hydroxide. Both agents have excellent cure rates, but there are no data about the comparison of postoperative healing periods. This study was designed to compare the postoperative morbidity rates of sodium hydroxide and phenol matricectomies. Forty-six patients with 154 ingrowing nail sides were treated with either sodium hydroxide or phenol matricectomy. In the postoperative period, the patients were evaluated for the duration and severity of pain, drainage, and peripheral tissue destruction; complete healing periods; and overall success rates. The incidence of pain was higher in the sodium hydroxide group on the first visit, on the second day, but all patients became pain-free after that. The incidence and duration of drainage and peripheral tissue destruction was significantly higher in the phenol group. The mean period for complete recovery was 10.8 days in the sodium hydroxide group, whereas it was 18.02 days in the phenol group. The overall success rates in the sodium hydroxide and phenol groups were found to be 95.1 and 95.8%, respectively. Both sodium hydroxide and phenol are effective agents giving high success rates, but sodium hydroxide causes less postoperative morbidity and provides faster recovery.

  1. Mixing Acid Salts and Layered Double Hydroxides in Nanoscale under Solid Condition

    PubMed Central

    Nakayama, Hirokazu; Hayashi, Aki

    2014-01-01

    The immobilization of potassium sorbate, potassium aspartate and sorbic acid in layered double hydroxide under solid condition was examined. By simply mixing two solids, immobilization of sorbate and aspartate in the interlayer space of nitrate-type layered double hydroxide, so called intercalation reaction, was achieved, and the uptakes, that is, the amount of immobilized salts and the interlayer distances of intercalation compounds were almost the same as those obtained in aqueous solution. However, no intercalation was achieved for sorbic acid. Although intercalation of sorbate and aspartate into chloride-type layered double hydroxide was possible, the uptakes for these intercalation compounds were lower than those obtained using nitrate-type layered double hydroxide. The intercalation under solid condition could be achieved to the same extent as for ion-exchange reaction in aqueous solution, and the reactivity was similar to that observed in aqueous solution. This method will enable the encapsulation of acidic drug in layered double hydroxide as nano level simply by mixing both solids. PMID:25080007

  2. Mixing Acid Salts and Layered Double Hydroxides in Nanoscale under Solid Condition.

    PubMed

    Nakayama, Hirokazu; Hayashi, Aki

    2014-07-30

    The immobilization of potassium sorbate, potassium aspartate and sorbic acid in layered double hydroxide under solid condition was examined. By simply mixing two solids, immobilization of sorbate and aspartate in the interlayer space of nitrate-type layered double hydroxide, so called intercalation reaction, was achieved, and the uptakes, that is, the amount of immobilized salts and the interlayer distances of intercalation compounds were almost the same as those obtained in aqueous solution. However, no intercalation was achieved for sorbic acid. Although intercalation of sorbate and aspartate into chloride-type layered double hydroxide was possible, the uptakes for these intercalation compounds were lower than those obtained using nitrate-type layered double hydroxide. The intercalation under solid condition could be achieved to the same extent as for ion-exchange reaction in aqueous solution, and the reactivity was similar to that observed in aqueous solution. This method will enable the encapsulation of acidic drug in layered double hydroxide as nano level simply by mixing both solids.

  3. Effective Construction of High-quality Iron Oxy-hydroxides and Co-doped Iron Oxy-hydroxides Nanostructures: Towards the Promising Oxygen Evolution Reaction Application

    NASA Astrophysics Data System (ADS)

    Zhang, Xinyu; An, Li; Yin, Jie; Xi, Pinxian; Zheng, Zhiping; Du, Yaping

    2017-03-01

    Rational design of high efficient and low cost electrocatalysts for oxygen evolution reaction (OER) plays an important role in water splitting. Herein, a general gelatin-assisted wet chemistry method is employed to fabricate well-defined iron oxy-hydroxides and transitional metal doped iron oxy-hydroxides nanomaterials, which show good catalytic performances for OER. Specifically, the Co-doped iron oxy-hydroxides (Co0.54Fe0.46OOH) show the excellent electrocatalytic performance for OER with an onset potential of 1.52 V, tafel slope of 47 mV/dec and outstanding stability. The ultrahigh oxygen evolution activity and strong durability, with superior performance in comparison to the pure iron oxy-hydroxide (FeOOH) catalysts, originate from the branch structure of Co0.54Fe0.46OOH on its surface so as to provide many active edge sites, enhanced mass/charge transport capability, easy release oxygen gas bubbles, and strong structural stability, which are advantageous for OER. Meanwhile, Co-doping in FeOOH nanostructures constitutes a desirable four-electron pathway for reversible oxygen evolution and reduction, which is potentially useful for rechargeable metal-air batteries, regenerative fuel cells, and other important clean energy devices. This work may provide a new insight into constructing the promising water oxidation catalysts for practical clean energy application.

  4. Effective Construction of High-quality Iron Oxy-hydroxides and Co-doped Iron Oxy-hydroxides Nanostructures: Towards the Promising Oxygen Evolution Reaction Application.

    PubMed

    Zhang, Xinyu; An, Li; Yin, Jie; Xi, Pinxian; Zheng, Zhiping; Du, Yaping

    2017-03-08

    Rational design of high efficient and low cost electrocatalysts for oxygen evolution reaction (OER) plays an important role in water splitting. Herein, a general gelatin-assisted wet chemistry method is employed to fabricate well-defined iron oxy-hydroxides and transitional metal doped iron oxy-hydroxides nanomaterials, which show good catalytic performances for OER. Specifically, the Co-doped iron oxy-hydroxides (Co 0.54 Fe 0.46 OOH) show the excellent electrocatalytic performance for OER with an onset potential of 1.52 V, tafel slope of 47 mV/dec and outstanding stability. The ultrahigh oxygen evolution activity and strong durability, with superior performance in comparison to the pure iron oxy-hydroxide (FeOOH) catalysts, originate from the branch structure of Co 0.54 Fe 0.46 OOH on its surface so as to provide many active edge sites, enhanced mass/charge transport capability, easy release oxygen gas bubbles, and strong structural stability, which are advantageous for OER. Meanwhile, Co-doping in FeOOH nanostructures constitutes a desirable four-electron pathway for reversible oxygen evolution and reduction, which is potentially useful for rechargeable metal-air batteries, regenerative fuel cells, and other important clean energy devices. This work may provide a new insight into constructing the promising water oxidation catalysts for practical clean energy application.

  5. [Antimicrobial effect of various calcium hydroxide on Porphyromonas endodontalis in vitro].

    PubMed

    Du, Ting-ting; Qiu, Li-hong; Jia, Ge; Yang, Di; Guo, Yan

    2012-04-01

    To compare the antimicrobial activity of Endocal, calcium hydroxide paste, Calxyl, Vitapex on Porphyromonas endodontalis(P.e). (1) The antimicrobial activity of different calcium hydroxide on P.e was examined at different exposure times by dynamic nephelometry. (2) 85 freshly extracted single-rooted human teeth were selected and cut at the amelocemental junction. All roots were randomly divided into five groups. The bacteria were incubated in each canal and were sampled and counted before and after enveloping five kinds of intercanal medicine seeded. Student's t test, One-way ANOVA were used with SPSS11.0 software package for statistical analysis. The bacteria from each group were reduced significantly after intracanal medication (P<0.05). The antibacterial efficacy of Endocal and calcium hydroxide paste were superior to others under dynamic nephelometry test (P<0.05). Endocal, calcium hydroxide paste, Calxyl, Vitapex had strong inhibitory effect on P.e from infected root canals, and the rate of bacteria clearance was 95%. The antimicrobial activity of Endocal was significantly greater than others (P<0.05). Endocal, calcium hydroxide paste, Calxyl and Vitapex were effective for intercanal disinfection. The antibacterial activity of Endocal is greater than Vitapex.

  6. Comparative evaluation of different forms of calcium hydroxide in apexification.

    PubMed

    Ghosh, Subhankar; Mazumdar, Dibyendu; Ray, Pradip Kumar; Bhattacharya, Bhaswar

    2014-01-01

    One out of every two children sustains a dental injury most often between 8 and 10 years of age. Majority of these teeth subsequently become non-vital and most often with immature apex. Management of these teeth is an enormous challenge for lack of apical stop. Calcium hydroxide in various formulations has maximum literature support in favor of successful apexification or induced apical closure. The aim of the following study is to determine the efficacy of calcium hydroxide in a different formulation to induce apexification. The present study was undertaken on 51 children of 8-10 years of age (both sexes) at Dr. R Ahmed Dental College and Hospital from April 2006 to March 2007. All children had one or two maxillary permanent central incisor (s), non-vital and apices open. In all the cases, apexification was attempted with either calcium hydroxide mixed with sterile distilled water, or calcium hydroxide plus iodoform in methyl cellulose base, or calcium hydroxide plus iodoform in polysilicone oil base. The success of apexification was determined on the basis of clinical and radiographic criteria. In the pre-operative asymptomatic cases (72.55%), failure occurred in only 5.45% cases and pre-operative symptomatic cases failure rate was as high as 35.71%. Success rate was 94.6% in cases with narrow open apices, whereas 64.28% in wide open apices. In cases with pre-existing apical radiolucencies, successful apexification occurred in 63.63% and success rate was 92.5% in the cases without pre-existing apical radiolucencies. Average time consumed for apexification was minimum with calcium hydroxide plus iodoform in polysilicone oil base. The overall success rate observed to be 86.27%, which is in close proximity to the findings of most of the previous studies across the globe.

  7. The effect of calcium hydroxide on the steroid component of Ledermix and Odontopaste.

    PubMed

    Athanassiadis, M; Jacobsen, N; Parashos, P

    2011-12-01

    To investigate the chemical interaction of calcium hydroxide with the corticosteroid triamcinolone acetonide in Ledermix Paste and in Odontopaste, a new steroid/antibiotic paste. Validated methods were developed to analyse the interaction of calcium hydroxide in two forms, Pulpdent Paste and calcium hydroxide powder, with triamcinolone acetonide within Odontopaste and Ledermix Paste. High-performance liquid chromatography (HPLC) was used to analyse the mixed samples of the pastes and calcium hydroxide. The concentration of triamcinolone acetonide within the pastes was determined over 0, 2, 6, 24 and 72-h time-points. All tests with the HPLC involved the testing of the standard with triplicate injections alongside the samples. All samples were tested in duplicate with each injected twice; therefore, four tests were performed for each investigation. Linearity, precision and specificity of the testing procedures and apparatus were validated. Descriptive statistics are provided. In both pastes, there was a marked rapid destruction of the triamcinolone acetonide steroid upon mixing with calcium hydroxide. Odontopaste suffered a lower rate of destruction of the triamcinolone acetonide component than Ledermix Paste, but both pastes showed very similar degrees of steroid destruction after 72 h. When using calcium hydroxide powder with Ledermix Paste, the triamcinolone was destroyed entirely and immediately. The addition of calcium hydroxide to Odontopaste or Ledermix Paste results in the rapid destruction of the steroid. © 2011 International Endodontic Journal.

  8. Hydroxide ion-mediated synthesis of monodisperse dopamine-melanin nanospheres.

    PubMed

    Cho, Soojeong; Kim, Shin-Hyun

    2015-11-15

    Dopamine-melanin nanospheres are promising materials for photoprotection, structural coloration, and thermoregulation due to their unusual optical and chemical properties. Here, we report the experimental parameters which influence size of dopamine-melanin nanospheres and uniformity. Dopamine precursors are oxidatively polymerized in basic aqueous medium. Therefore, concentration of hydroxide ions significantly influences reaction rate and size of nanospheres. To investigate the effect of hydroxide ions, we adjust three different parameters which affect pH of medium: concentration of sodium hydroxide and dopamine hydrochloride, and reaction temperature. At constant temperature, concentration of hydroxide ions is linearly proportional to initial reaction rates which determine the number of nuclei for nanosphere growth. Temperature alters not only initial reaction rate but also diffusivity of molecules, leading to deviation from the relation between the reaction rate and the number of nuclei. The diameter of dopamine-melanin nanospheres can be readily controlled in a range of 80-490nm through adjusting concentration of dopamine precursor, while maintaining uniform-size distribution and dispersion stability. The synthesized nanospheres are analyzed to confirm the chemical structure, which is composed of approximately 6 indole units. Moreover, surface and chemical properties of the nanospheres are characterized to provide valuable information for surface modification and application. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Sodium hydroxide catalyzed monodispersed high surface area silica nanoparticles.

    PubMed

    Bhakta, Snehasis; Dixit, Chandra K; Bist, Itti; Jalil, Karim Abdel; Suib, Steven L; Rusling, James F

    2016-07-01

    Understanding of the synthesis kinetics and our ability to modulate medium conditions allowed us to generate nanoparticles via an ultra-fast process. The synthesis medium is kept quite simple with tetraethyl orthosilicate (TEOS) as precursor and 50% ethanol and sodium hydroxide catalyst. Synthesis is performed under gentle conditions at 20 °C for 20 min Long synthesis time and catalyst-associated drawbacks are most crucial in silica nanoparticle synthesis. We have addressed both these bottlenecks by replacing the conventional Stober catalyst, ammonium hydroxide, with sodium hydroxide. We have reduced the overall synthesis time from 20 to 1/3 h, ~60-fold decrease, and obtained highly monodispersed nanoparticles with 5-fold higher surface area than Stober particles. We have demonstrated that the developed NPs with ~3-fold higher silane can be used as efficient probes for biosensor applications.

  10. Vibrational dynamics of aqueous hydroxide solutions probed using broadband 2DIR spectroscopy

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Mandal, Aritra; Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139; Tokmakoff, Andrei, E-mail: tokmakoff@uchicago.edu

    2015-11-21

    We employed ultrafast transient absorption and broadband 2DIR spectroscopy to study the vibrational dynamics of aqueous hydroxide solutions by exciting the O–H stretch vibrations of the strongly hydrogen-bonded hydroxide solvation shell water and probing the continuum absorption of the solvated ion between 1500 and 3800 cm{sup −1}. We observe rapid vibrational relaxation processes on 150–250 fs time scales across the entire probed spectral region as well as slower vibrational dynamics on 1–2 ps time scales. Furthermore, the O–H stretch excitation loses its frequency memory in 180 fs, and vibrational energy exchange between bulk-like water vibrations and hydroxide-associated water vibrations occursmore » in ∼200 fs. The fast dynamics in this system originate in strong nonlinear coupling between intra- and intermolecular vibrations and are explained in terms of non-adiabatic vibrational relaxation. These measurements indicate that the vibrational dynamics of the aqueous hydroxide complex are faster than the time scales reported for long-range transport of protons in aqueous hydroxide solutions.« less

  11. Electron-beam-evaporated thin films of hafnium dioxide for fabricating electronic devices

    DOE PAGES

    Xiao, Zhigang; Kisslinger, Kim

    2015-06-17

    Thin films of hafnium dioxide (HfO 2) are widely used as the gate oxide in fabricating integrated circuits because of their high dielectric constants. In this paper, the authors report the growth of thin films of HfO 2 using e-beam evaporation, and the fabrication of complementary metal-oxide semiconductor (CMOS) integrated circuits using this HfO 2 thin film as the gate oxide. The authors analyzed the thin films using high-resolution transmission electron microscopy and electron diffraction, thereby demonstrating that the e-beam-evaporation-grown HfO 2 film has a polycrystalline structure and forms an excellent interface with silicon. Accordingly, we fabricated 31-stage CMOS ringmore » oscillator to test the quality of the HfO 2 thin film as the gate oxide, and obtained excellent rail-to-rail oscillation waveforms from it, denoting that the HfO 2 thin film functioned very well as the gate oxide.« less

  12. The effect of calcium hydroxide on the antibiotic component of Odontopaste and Ledermix paste.

    PubMed

    Athanassiadis, M; Jacobsen, N; Nassery, K; Parashos, P

    2013-06-01

    To investigate the chemical interaction of calcium hydroxide with the antibiotics demeclocycline calcium in Ledermix Paste and clindamycin hydrochloride in Odontopaste. Validated methods were developed to analyse the interaction of calcium hydroxide in two forms, Pulpdent and calcium hydroxide powder, with the two antibiotics. High-performance liquid chromatography (HPLC) was used to analyse the mixed samples of the pastes and calcium hydroxide. The concentration of demeclocycline calcium over 0-, 1-, 18-, 24-, 72-h and 7-day time-points was determined. The concentration of clindamycin hydrochloride over 1-, 6-, 24-, 72-h and 7-day time-points was determined. All tests with HPLC involved testing of the standard in duplicate alongside the samples. Linearity, precision and specificity of the testing procedures and apparatus were validated. Descriptive statistics are provided. The antibiotics in both Odontopaste and Ledermix Paste were affected by the addition of calcium hydroxide. When mixed with calcium hydroxide powder, Odontopaste had a 2% loss of clindamycin hydrochloride over 7 days, but when mixed with Pulpdent, there was a 36% loss over 7 days. Ledermix Paste showed an 80% loss of demeclocycline calcium over 7 days when mixed with calcium hydroxide powder and a 19% loss when mixed with Pulpdent over the 7-day period. The addition of calcium hydroxide to Odontopaste or Ledermix Paste results in reductions of the respective antibiotic over a 7-day time period. © 2012 International Endodontic Journal. Published by Blackwell Publishing Ltd.

  13. Safety Assessment of Alumina and Aluminum Hydroxide as Used in Cosmetics.

    PubMed

    Becker, Lillian C; Boyer, Ivan; Bergfeld, Wilma F; Belsito, Donald V; Hill, Ronald A; Klaassen, Curtis D; Liebler, Daniel C; Marks, James G; Shank, Ronald C; Slaga, Thomas J; Snyder, Paul W; Andersen, F Alan

    2016-11-01

    This is a safety assessment of alumina and aluminum hydroxide as used in cosmetics. Alumina functions as an abrasive, absorbent, anticaking agent, bulking agent, and opacifying agent. Aluminum hydroxide functions as a buffering agent, corrosion inhibitor, and pH adjuster. The Food and Drug Administration (FDA) evaluated the safe use of alumina in several medical devices and aluminum hydroxide in over-the-counter drugs, which included a review of human and animal safety data. The Cosmetic Ingredient Review (CIR) Expert Panel considered the FDA evaluations as part of the basis for determining the safety of these ingredients as used in cosmetics. Alumina used in cosmetics is essentially the same as that used in medical devices. This safety assessment does not include metallic or elemental aluminum as a cosmetic ingredient. The CIR Expert Panel concluded that alumina and aluminum hydroxide are safe in the present practices of use and concentration described in this safety assessment. © The Author(s) 2016.

  14. Sodium hydroxide permethylation of heparin disaccharides.

    PubMed

    Heiss, Christian; Wang, Zhirui; Azadi, Parastoo

    2011-03-30

    Permethylation is a valuable and widely used tool for the mass spectrometry of carbohydrates, improving sensitivity and fragmentation and increasing the amount of information that can be obtained from tandem mass spectrometric experiments. Permethylation of most glycans is easily performed with sodium hydroxide and iodomethane in dimethyl sulfoxide (DMSO). However, permethylation has not been widely used in the mass spectrometry of glycosaminoglycan (GAG) oligosaccharides, partly because it has required the use of the difficult Hakomori method employing the methylsulfinylmethanide ('dimsyl') base, which has to be made in a tedious process. Additionally, the Hakomori method is not as effective as the sodium hydroxide method in making fully methylated derivatives. A further problem in the permethylation of highly sulfated oligosaccharides is their limited solubility in DMSO. This paper describes the use of the triethylammonium counterion to overcome this problem, as well as the application of the sodium hydroxide method to make permethylated heparin disaccharides and their workup to yield fully methylated disaccharides for electrospray ionization mass spectrometry. The ease, speed, and effectiveness of the described methodology should open up permethylation of GAG oligosaccharides to a wider circle of mass spectrometrists and enable them to develop further derivatization schemes in the effort to rapidly elucidate the structure of these important molecules. Permethylation may also provide new ways of separating GAG oligosaccharides in LC/MS, their increased hydrophobicity making them amenable for reversed-phase chromatography without the need for ion pairing reagents. Copyright © 2011 John Wiley & Sons, Ltd.

  15. Effect of nitrogen on tensile properties and structures of T-111 (tantalum, 8 percent tungsten, 2 percent hafnium) tubing

    NASA Technical Reports Server (NTRS)

    Buzzard, R. J.; Metroka, R. R.

    1973-01-01

    The effect of controlled nitrogen additions was evaluated on the mechanical properties of T-111 (Ta-8W-2Hf) fuel pin cladding material proposed for use in a lithium-cooled nuclear reactor concept. Additions of 80 to 1125 ppm nitrogen resulted in increased strengthening of T-111 tubular section test specimens at temperatures of 25 to 1200 C. Homogeneous distributions of up to 500 ppm nitrogen did not seriously decrease tensile ductility. Both single and two-phase microstructures, with hafnium nitride as the second phase, were evaluated in this study.

  16. Atomic hydrogen in. gamma. -irradiated hydroxides of alkaline-earth elements

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Spitsyn, V.I.; Yurik, T.K.; Barsova, L.I.

    1982-04-01

    Atomic hydrogen is an important intermediate product formed in the radiolysis of compounds containing X-H bonds. H atoms have been detected in irradiated matrices of H/sub 2/ and inert gases at 4/sup 0/K, in irradiated ice and frozen solutions of acids in irradiated salts and in other systems. Here results are presented from a study of the ESR spectra of H atoms generated in polycrystalline hydroxides of alkaline-earth elements that have been ..gamma..-irradiated at 77/sup 0/K, after preliminary treatment at various temperatures. For the first time stabilization of atomic hydrogen in ..gamma..-irradiated polycrystalline alkaline-earth element hydroxides has been detected. Dependingmore » on the degree of dehydroxylation, several types of hydrogen atoms may be stabilized in the hydroxides, these hydrogen atoms having different radiospectroscopic parameters. In the magnesium-calcium-strontium-barium hydroxide series, a regular decrease has been found in the hfi constants for H atoms with the cations in the immediate surroundings. A direct proportionality has been found between the parameters ..delta..A/A/sub 0/ and the polarizability of the cation.« less

  17. Pyroelectric response in crystalline hafnium zirconium oxide (Hf 1- x Zr x O 2 ) thin films

    DOE PAGES

    Smith, S. W.; Kitahara, A. R.; Rodriguez, M. A.; ...

    2017-02-13

    Pyroelectric coefficients were measured for 20 nm thick crystalline hafnium zirconium oxide (Hf 1-xZr xO 2) thin films across a composition range of 0 ≤ x ≤ 1. Pyroelectric currents were collected near room temperature under zero applied bias and a sinusoidal oscillating temperature profile to separate the influence of non-pyroelectric currents. The pyroelectric coefficient was observed to correlate with zirconium content, increased orthorhombic/tetragonal phase content, and maximum polarization response. The largest measured absolute value was 48 μCm -2K -1 for a composition with x = 0.64, while no pyroelectric response was measured for compositions which displayed no remanent polarizationmore » (x = 0, 0.91, 1).« less

  18. The high-pressure phase transitions of hydroxides

    NASA Astrophysics Data System (ADS)

    Nishi, M.; Kuwayama, Y.; Tsuchiya, J.; Tsuchiya, T.; Irifune, T.

    2017-12-01

    The discovery of new high-pressure hydrous minerals has important implications for understanding the structure, dynamics, and evolution of the Earth, since hydrogen significantly affects the physical properties and stabilities of Earth's constituent minerals. Whereas hydrous minerals commonly dehydrate under pressures of around a few tens of gigapascals (GPa) and at temperature around 1,500 K, those with CaCl2-type crystal structure, MgSiO4H2 phase H, δ-AlOOH and ɛ-FeOOH, are known to be stable at pressures corresponding to the lower mantle. However, although the CaCl2-type hydroxides were suggested to form a solid solution owing to their similar crystal structure, there are few experimental studies on the stability of the hydroxide in such multicomponent. Moreover, ab initio calculations have predicted that some CaCl2-type hydroxides transform to pyrite-type structure at higher pressures. Here, we conducted high pressure-temperature experiments on pure AlOOH, FeOOH, and their solid solutions, with the aid of these first-principles predictions. We use in situ X-ray measurements in conjunction with a multi-anvil apparatus to study the high-pressure behaviour of hydroxides in the multicomponent system under middle lower mantle conditions. Solid solutions in wide compositional ranges between CaCl2-type δ-AlOOH and ɛ-FeOOH were recognized from X-ray diffraction patterns. Also, unit cell volume of FeOOH and (Al,Fe)OOH significantly decreased accompanied with the spin transition of iron at 50 GPa. Thus, the wide compositional ranges in CaCl2-type hydroxide are maintained beyond the depth of the middle lower mantle, where the spin transition of iron occurs. We used a laser-heated diamond anvil cell in order to study the stability of AlOOH and FeOOH at higher pressures above 70 GPa. We observed that ɛ-FeOOH transforms to the pyrite-type structure at above 80 GPa, which is consistent with the theoretical prediction. At conditions above 190 GPa and 2,500 K, we observed

  19. The effect of polymers onto the size of zinc layered hydroxide salt and its calcined product

    NASA Astrophysics Data System (ADS)

    Hussein, Mohd Zobir bin; Ghotbi, Mohammad Yeganeh; Yahaya, Asmah Hj; Abd Rahman, Mohd Zaki

    2009-02-01

    Zinc hydroxide nitrate, a brucite-like layered material was synthesized using pH control method. Poly(vinyl alcohol) and poly(ethylene glycol) were used at various percentages as size decreasing agents during the synthesis of zinc hydroxide nitrate. SEM and PXRD showed the decrease of size and thickness of the resultant zinc hydroxide nitrates. TG and surface area data confirmed the decrease of the particle sizes, too. When zinc hydroxide nitrates were heat treated at 500 °C, the physical properties of nano zinc oxides obtained depended on the parent material, zinc hydroxide nitrate.

  20. PROCESS FOR SEPARATING PLUTONIUM BY REPEATED PRECIPITATION WITH AMPHOTERIC HYDROXIDE CARRIERS

    DOEpatents

    Faris, B.F.

    1960-04-01

    A multiple carrier precipitation method is described for separating and recovering plutonium from an aqueous solution. The hydroxide of an amphoteric metal is precipitated in an aqueous plutonium-containing solution. This precipitate, which carries plutonium, is then separated from the supernatant liquid and dissolved in an aqueous hydroxide solution, forming a second plutonium- containing solution. lons of an amphoteric metal which forms an insoluble hydroxide under the conditions existing in this second solution are added to the second solution. The precipitate which forms and which carries plutonium is separated from the supernatant liquid. Amphoteric metals which may be employed are aluminum, bibmuth, copper, cobalt, iron, lanthanum, nickel, and zirconium.

  1. Detection of interstellar sodium hydroxide in self-absorption toward the galactic center

    NASA Technical Reports Server (NTRS)

    Hollis, J. M.; Rhodes, P. J.

    1982-01-01

    A weak self-absorbed emission line, which is identified as the J = 4-3 transition of sodium hydroxide, has been detected in the direction of Sgr B2(OH). The correspondingly weak Sgr B2(QH) emission line U75406, previously reported as an unidentified spectral feature by other investigators, is consistent with the J = 3-2 transition of sodium hydroxide. This detection may represent the first evidence of a grain reaction formation mechanism for simple metal hydroxides. The detection of H62 Delta toward Orion A is also reported.

  2. Layered double hydroxide stability. 2. Formation of Cr(III)-containing layered double hydroxides directly from solution

    NASA Technical Reports Server (NTRS)

    Boclair, J. W.; Braterman, P. S.; Jiang, J.; Lou, S.; Yarberry, F.

    1999-01-01

    Solutions containing divalent metal [M(II) = Mg2+, Zn2+, Co2+, Ni2+, Mn2+] chlorides and CrCl3 6H2O were titrated with NaOH to yield, for M(II) = Zn, Co, and Ni, hydrotalcite-like layered double hydroxides (LDHs), [[M(II)]1-z[Cr(III)]z(OH)2][Cl]z yH2O, in a single step, without intermediate formation of chromium hydroxide. Analysis of the resultant titration curves yields solubility constants for these compounds. These are in the order Zn < Ni approximately Co, with a clear preference for formation of the phase with z = 1/3. With Mg2+ as chloride, titration gives a mixture of Cr(OH)3 and Mg(OH)2, but the metal sulfates give Mg2Cr(OH)6 1/2(SO4) by a two-step process. Titrimetric and spectroscopic evidence suggests short-range cation order in the one-step LDH systems.

  3. 21 CFR 73.2326 - Chromium hydroxide green.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2326 Chromium hydroxide green. (a) Identity and... in coloring externally applied cosmetics, including those intended for use in the area of the eye, in...

  4. 21 CFR 73.2326 - Chromium hydroxide green.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2326 Chromium hydroxide green. (a) Identity and... in coloring externally applied cosmetics, including those intended for use in the area of the eye, in...

  5. 21 CFR 73.2326 - Chromium hydroxide green.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2326 Chromium hydroxide green. (a) Identity and... in coloring externally applied cosmetics, including those intended for use in the area of the eye, in...

  6. INFLUENCE OF IODOFORM ON ANTIMICROBIAL POTENTIAL OF CALCIUM HYDROXIDE

    PubMed Central

    Estrela, Carlos; Estrela, Cyntia Rodrigues de Araújo; Hollanda, Augusto César Braz; Decurcio, Daniel de Almeida; Pécora, Jesus Djalma

    2006-01-01

    The purpose of this research was to verify the influence of Iodoform on antimicrobial potential of calcium hydroxide. S. aureus, E. faecalis, P. aeruginosa, B. subtilis, C. albicans were the biological indicators. The substances tested were: calcium hydroxide + saline; calcium hydroxide + Iodoform + saline; Iodoform + saline. For the agar diffusion test, 18 Petri plates with 20 ml of BHI agar were inoculated with the microbial suspensions. Fifty-four cavities were made and filled with the substances tested. The diameters of microbial inhibition were then measured. In direct exposure test, 162 #50 sterile absorbent paper points were immersed in the experimental suspensions for 5 min, and covered with the pastes. At intervals of 24, 48 and 72 hours, the paper points were immersed in 10 ml of Letheen Broth, followed by incubation at 37°°C for 48h. Microbial growth was evaluated by turbidity of the culture medium. A 0.1 ml inoculum obtained from the Letheen Broth was transferred to 7 ml of BHI, and incubated at 37°°C for 48h. Bacterial growth was again evaluated by turbidity of the culture medium. The calcium hydroxide associated with the saline or the iodoform plus saline showed antimicrobial effectiveness in both experimental methods. The iodoform paste presented antimicrobial ineffectiveness for the agar diffusion test on all biological microorganisms and for the direct exposure test on B. subtilis and on the mixture. PMID:19089027

  7. Transformation of zinc hydroxide chloride monohydrate to crystalline zinc oxide.

    PubMed

    Moezzi, Amir; Cortie, Michael; McDonagh, Andrew

    2016-04-25

    Thermal decomposition of layered zinc hydroxide double salts provides an interesting alternative synthesis for particles of zinc oxide. Here, we examine the sequence of changes occurring as zinc hydroxide chloride monohydrate (Zn5(OH)8Cl2·H2O) is converted to crystalline ZnO by thermal decomposition. The specific surface area of the resultant ZnO measured by BET was 1.3 m(2) g(-1). A complicating and important factor in this process is that the thermal decomposition of zinc hydroxide chloride is also accompanied by the formation of volatile zinc-containing species under certain conditions. We show that this volatile compound is anhydrous ZnCl2 and its formation is moisture dependent. Therefore, control of atmospheric moisture is an important consideration that affects the overall efficiency of ZnO production by this process.

  8. Tribo-electrochemical characterization of hafnium multilayer systems deposited on nitride/vanadium nitride AISI 4140 steel

    NASA Astrophysics Data System (ADS)

    Mora, M.; Vera, E.; Aperador, W.

    2016-02-01

    In this work is presented the synergistic behaviour among corrosion/wear (tribocorrosion) of the multilayer coatings hafnium nitride/vanadium nitride [HfN/VN]n. The multilayers were deposited on AISI 4140 steel using the technique of physical vapor deposition PVD magnetron sputtering, the tests were performed using a pin-on-disk tribometer, which has an adapted potentiostat galvanostat with three-electrode electrochemical cell. Tribocorrosive parameters such as: Friction coefficient between the coating and the counter body (100 Cr6 steel ball); Polarization resistance by means of electrochemical impedance spectroscopy technique and corrosion rate by polarization curves were determined. It was observed an increase in the polarization resistance, a decrease in the corrosion rate and a low coefficient of friction in comparison with the substrate, due to an increase on the number of bilayers.

  9. Synthesis of High Symmetry Phase of Hafnium Dioxide Thin Films and Nickel Ferrite's Effect on Microstructure in Composite Heterostructure

    NASA Astrophysics Data System (ADS)

    Straka, Weston J.

    Hafnium dioxide has attracted a great deal of attention recently due to its potential use in two different electronic applications: CMOS and FeRAM. In CMOS, the usefulness of hafnia comes in due to its high dielectric constant and compatibility with current IC processing parameters. For FeRAM, hafnia's recent discovery to exhibit ferroelectricity in an orthorhombic phase makes this material attractive for replacement of the ferroelectric material in FeRAM. This study shows the feasibility of depositing thin films of hafnium oxide via chemical solution deposition for integration into these devices. The processing parameters necessary to produce this phase show how non-equilibrium processing plays a role in its synthesis. The temperature necessary to achieve the high symmetry phase was at 725 °C for 3 minutes on sapphire, silicon, and coated silicon substrates. The thermal conductivity of each was viewed as the property that allowed the hafnia formation. The dielectric constant of the hafnia films were between 30 and 32 with low dissipation factors and up to 47 with a poor dissipation factor all at 1 kHz. The formation of this phase was shown to be thickness independent with the high symmetry phase existing up to 300 nm film thickness. Interfacing the hafnia film with nickel ferrite was also studied to identify the possibility of using this composite for non-destructive reading of FeRAM. The magnetic properties showed an unchanged nickel ferrite film but the interface between the two was poor leading to the conclusion that more work must be done to successfully integrate these two films.

  10. Bonding by Hydroxide-Catalyzed Hydration and Dehydration

    NASA Technical Reports Server (NTRS)

    Gwo, Dz-Hung

    2008-01-01

    A simple, inexpensive method for bonding solid objects exploits hydroxide-catalyzed hydration and dehydration to form silicate-like networks in thin surface and interfacial layers between the objects. The method can be practiced at room temperature or over a wide range of temperatures. The method was developed especially to enable the formation of precise, reliable bonds between precise optical components. The bonds thus formed exhibit the precision and transparency of bonds formed by the conventional optical-contact method and the strength and reliability of high-temperature frit bonds. The method also lends itself to numerous non-optical applications in which there are requirements for precise bonds and/or requirements for bonds, whether precise or imprecise, that can reliably withstand severe environmental conditions. Categories of such non-optical applications include forming composite materials, coating substrates, forming laminate structures, and preparing objects of defined geometry and composition. The method is applicable to materials that either (1) can form silicate-like networks in the sense that they have silicate-like molecular structures that are extensible into silicate-like networks or (2) can be chemically linked to silicate-like networks by means of hydroxide-catalyzed hydration and dehydration. When hydrated, a material of either type features surface hydroxyl (-OH) groups. In this method, a silicate-like network that bonds two substrates can be formed either by a bonding material alone or by the bonding material together with material from either or both of the substrates. Typically, an aqueous hydroxide bonding solution is dispensed and allowed to flow between the mating surfaces by capillary action. If the surface figures of the substrates do not match precisely, bonding could be improved by including a filling material in the bonding solution. Preferably, the filling material should include at least one ingredient that can be hydrated to

  11. Influence of calcium hydroxide debris on the quality of endodontic apical seal.

    PubMed

    Contardo, L; De Luca, M; Bevilacqua, L; Breschi, L; Di Lenarda, R

    2007-10-01

    The aim of the study was to study investigate the influence of calcium hydroxide used as intermediate medication on the quality of apical seal of a silicon based and an experimental resin based endodontic sealer. Eighty endodontic canals were prepared and divided in four groups. Calcium hydroxide was applied in groups 2 and 4. After 7 days, medication was removed and canals were filled with gutta-percha and RoekoSeal Automix (groups 1 and 2) or Scotchbond MP+C&B cement B (groups 3 and 4). Specimens were placed into India ink, cleared and analyzed under a stereomicroscope to investigate apical leakage. Specimens that received calcium hydroxide medication showed leakage means higher than the corresponding untreated ones (i.e. group 1< group 2 and group 3< group 4; P<0.001). Calcium hydroxide interferes with the sealing ability of silicon based sealer, since it frequently remains entrapped within the endodontic space even after careful removal procedures.

  12. Comparison of sodium hydroxide and calcium hydroxide pretreatments on the enzymatic hydrolysis and lignin recovery of sugarcane bagasse.

    PubMed

    Chang, Menglei; Li, Denian; Wang, Wen; Chen, Dongchu; Zhang, Yuyuan; Hu, Huawen; Ye, Xiufang

    2017-11-01

    Sodium hydroxide (NaOH) and calcium hydroxide (Ca(OH) 2 ) respectively dissolved in water and 70% glycerol were applied to treat sugarcane bagasse (SCB) under the condition of 80°C for 2h. NaOH solutions could remove more lignin and obtain higher enzymatic hydrolysis efficiency of SCB than Ca(OH) 2 solutions. Compared with the alkali-water solutions, the enzymatic hydrolysis of SCB treated in NaOH-glycerol solution decreased, while that in Ca(OH) 2 -glycerol solution increased. The lignin in NaOH-water pretreatment liquor could be easily recovered by calcium chloride (CaCl 2 ) at room temperature, but that in Ca(OH) 2 -water pretreatment liquor couldn't. NaOH pretreatment is more suitable for facilitating enzymatic hydrolysis and lignin recovery of SCB than Ca(OH) 2 pretreatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. The effects of lithium hydroxide solution on alkali silica reaction gels created with opal

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Mitchell, Lyndon D.; Beaudoin, James J.; Grattan-Bellew, Patrick

    The reaction of Nevada opal with calcium hydroxide, potassium hydroxide and lithium hydroxide solutions was investigated. In addition, opal was exposed to a combined solution of these three hydroxides. The progress of the three reactions was followed using X-ray diffraction (XRD), {sup 29}Si nuclear magnetic resonance (NMR) and scanning electron microscopy (SEM). The XRD results indicated the presence of a low-angle peak exclusive to the lithium-based reactions. The NMR results suggested a change in the silicate structure in the presence of lithium. These techniques indicated that the reaction of the alkali with the opal starting material is inhibited and perhapsmore » stopped in the presence of lithium hydroxide. SEM revealed that the morphology of the reaction products on the surface of the reacted opal grains is markedly different invariably. It was concluded that evidence to support the theory of a protective layer exists and that the nature of the layer varies with ion type.« less

  14. The hypocholesterolemic effect of an antacid containing aluminum hydroxide.

    PubMed

    Sperber, A D; Henkin, Y; Zuili, I; Bearman, J E; Shany, S

    1991-12-01

    To evaluate the efficacy, safety, and hypocholesterolemic effect of an aluminum hydroxide-containing antacid in hypercholesterolemic individuals. A prospective, randomized, double-masked, placebo-controlled phase of 2 months' duration, followed by an open-design treatment phase of 2 months' duration and a washout phase of 2 months' duration. Family practice clinics of two rural communities (kibbutzim) in Israel. Fifty-six men and women with hypercholesterolemia (type IIa or IIb). Fifty individuals completed the study. After 2 months of dietary modification (low-fat, low-cholesterol diet), the participants were randomized into two matched groups. Group 1 (28 participants) was treated for 2 months with a chewable antacid tablet containing simethicone, magnesium hydroxide, and 113 mg of aluminum hydroxide per tablet, at a dose of two tablets four times daily. Group 2 (22 participants) was given a similar number of placebo tablets for 2 months. During the following 2 months, both groups received the antacid at the above dose. Lipoprotein levels were evaluated at baseline and every 2 months thereafter for 6 months. Compared with pretreatment levels, Group 1 experienced a decrease in low-density lipoprotein cholesterol (LDL-C) of 9.8% after 2 months (p less than 0.001) and 18.5% after 4 months (p less than 0.001). Compared with Group 2, the decrease in LDL-C in Group 1 was 6.2% at the end of the 2-month double-masked, placebo phase. Although the high-density lipoprotein cholesterol (HDL-C) was also reduced in Group 1 at the end of 4 months of therapy (10.2%), the HDL-C/LDL-C ratio increased by 13% during the same interval (p less than 0.05). The treatment was well tolerated, with minimal side effects. An aluminum hydroxide-containing antacid reduces LDL-C in hypercholesterolemic individuals. Although HDL-C was also reduced to a lesser extent, the overall atherogenic index was improved. Further studies should be conducted to evaluate the long-term safety and efficacy of

  15. 40 CFR 415.60 - Applicability; description of the chlorine and sodium or potassium hydroxide production subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... chlorine and sodium or potassium hydroxide production subcategory. 415.60 Section 415.60 Protection of... MANUFACTURING POINT SOURCE CATEGORY Chlor-alkali Subcategory (Chlorine and Sodium or Potassium Hydroxide Production) § 415.60 Applicability; description of the chlorine and sodium or potassium hydroxide production...

  16. 40 CFR 415.60 - Applicability; description of the chlorine and sodium or potassium hydroxide production subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... chlorine and sodium or potassium hydroxide production subcategory. 415.60 Section 415.60 Protection of... MANUFACTURING POINT SOURCE CATEGORY Chlor-alkali Subcategory (Chlorine and Sodium or Potassium Hydroxide Production) § 415.60 Applicability; description of the chlorine and sodium or potassium hydroxide production...

  17. 40 CFR 415.60 - Applicability; description of the chlorine and sodium or potassium hydroxide production subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... chlorine and sodium or potassium hydroxide production subcategory. 415.60 Section 415.60 Protection of... MANUFACTURING POINT SOURCE CATEGORY Chlor-alkali Subcategory (Chlorine and Sodium or Potassium Hydroxide Production) § 415.60 Applicability; description of the chlorine and sodium or potassium hydroxide production...

  18. 40 CFR 415.60 - Applicability; description of the chlorine and sodium or potassium hydroxide production subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... chlorine and sodium or potassium hydroxide production subcategory. 415.60 Section 415.60 Protection of... MANUFACTURING POINT SOURCE CATEGORY Chlor-alkali Subcategory (Chlorine and Sodium or Potassium Hydroxide Production) § 415.60 Applicability; description of the chlorine and sodium or potassium hydroxide production...

  19. 40 CFR 415.60 - Applicability; description of the chlorine and sodium or potassium hydroxide production subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... chlorine and sodium or potassium hydroxide production subcategory. 415.60 Section 415.60 Protection of... MANUFACTURING POINT SOURCE CATEGORY Chlor-alkali Subcategory (Chlorine and Sodium or Potassium Hydroxide Production) § 415.60 Applicability; description of the chlorine and sodium or potassium hydroxide production...

  20. Improvement of the process for electrochemical impregnation of nickel hydroxide electrodes

    NASA Technical Reports Server (NTRS)

    Comtat, M.; Lafage, B.; Leonardi, J.

    1986-01-01

    Nickel hydroxide electrodes containing 11g/dsqm hydroxide, with capacities of 3.6 to 3.8 Ah/dsqm were prepared at 353 K by electrochemical impregnation. The reproducibility of the results is obtained by readjusting the pH before each preparation. The control of each electrode is done during two cycles of charge and discharge following the manufacture by a potential relaxation method.

  1. Hafnium Films and Magnetic Shielding for TIME, A mm-Wavelength Spectrometer Array

    NASA Astrophysics Data System (ADS)

    Hunacek, J.; Bock, J.; Bradford, C. M.; Butler, V.; Chang, T.-C.; Cheng, Y.-T.; Cooray, A.; Crites, A.; Frez, C.; Hailey-Dunsheath, S.; Hoscheit, B.; Kim, D. W.; Li, C.-T.; Marrone, D.; Moncelsi, L.; Shirokoff, E.; Steinbach, B.; Sun, G.; Trumper, I.; Turner, A.; Uzgil, B.; Weber, A.; Zemcov, M.

    2018-04-01

    TIME is a mm-wavelength grating spectrometer array that will map fluctuations of the 157.7-μm emission line of singly ionized carbon ([CII]) during the epoch of reionization (redshift z ˜ 5-9). Sixty transition-edge sensor (TES) bolometers populate the output arc of each of the 32 spectrometers, for a total of 1920 detectors. Each bolometer consists of gold absorber on a ˜ 3 × 3 mm silicon nitride micro-mesh suspended near the corners by 1 × 1 × 500 μm silicon nitride legs targeting a photon-noise-dominated NEP ˜ 1 × 10^{-17} W/√{Hz} . Hafnium films are explored as a lower-T_c alternative to Ti (500 mK) for TIME TESs, allowing thicker support legs for improved yield. Hf T_c is shown to vary between 250 and 450 mK when varying the resident Ar pressure during deposition. Magnetic shielding designs and simulations are presented for the TIME first-stage SQUIDs. Total axial field suppression is predicted to be 5 × 10^7.

  2. Solvent and process for recovery of hydroxide from aqueous mixtures

    DOEpatents

    Moyer, Bruce A.; Chambliss, C. Kevin; Bonnesen, Peter V.; Keever, Tamara J.

    2001-01-01

    Hydroxide values and associated alkali metal may be recovered from alkaline aqueous solutions using classes of fluorinated alcohols in a water immiscible solvent. The alcohols are characterized by fluorine substituents which are proximal to the acidic alcohol protons and are located to adjust the acidity of the extractant and the solubility of the extractant in the solvent. A method for stripping the extractant and solvent to regenerate the extractant and purified aqueous hydroxide solution is described.

  3. Nickel hydroxides and related materials: a review of their structures, synthesis and properties

    PubMed Central

    Hall, David S.; Lockwood, David J.; Bock, Christina; MacDougall, Barry R.

    2015-01-01

    This review article summarizes the last few decades of research on nickel hydroxide, an important material in physics and chemistry, that has many applications in engineering including, significantly, batteries. First, the structures of the two known polymorphs, denoted as α-Ni(OH)2 and β-Ni(OH)2, are described. The various types of disorder, which are frequently present in nickel hydroxide materials, are discussed including hydration, stacking fault disorder, mechanical stresses and the incorporation of ionic impurities. Several related materials are discussed, including intercalated α-derivatives and basic nickel salts. Next, a number of methods to prepare, or synthesize, nickel hydroxides are summarized, including chemical precipitation, electrochemical precipitation, sol–gel synthesis, chemical ageing, hydrothermal and solvothermal synthesis, electrochemical oxidation, microwave-assisted synthesis, and sonochemical methods. Finally, the known physical properties of the nickel hydroxides are reviewed, including their magnetic, vibrational, optical, electrical and mechanical properties. The last section in this paper is intended to serve as a summary of both the potentially useful properties of these materials and the methods for the identification and characterization of ‘unknown’ nickel hydroxide-based samples. PMID:25663812

  4. Nickel hydroxide positive electrode for alkaline rechargeable battery

    DOEpatents

    Young, Kwo; Wang, Lixin; Mays, William; Reichman, Benjamin; Chao-Ian, Hu; Wong, Diana; Nei, Jean

    2018-04-03

    Certain nickel hydroxide active cathode materials for use in alkaline rechargeable batteries are capable of transferring >1.3 electrons per Ni atom under reversible electrochemical conditions. The specific capacity of the nickel hydroxide active materials is for example .gtoreq.325 mAh/g. The cathode active materials exhibit an additional discharge plateau near 0.8 V vs. a metal hydride (MH) anode. Ni in an oxidation state of less than 2, such as Ni.sup.1+, is able to participate in electrochemical reactions when using the present cathode active materials. It is possible that up to 2.3 electrons, up to 2.5 electrons or more may be transferred per Ni atom under electrochemical conditions.

  5. Nickel hydroxide positive electrode for alkaline rechargeable battery

    DOEpatents

    Young, Kwo; Wang, Lixin; Mays, William; Reichman, Benjamin; Chao-Ian, Hu; Wong, Diana; Nei, Jean

    2018-02-20

    Certain nickel hydroxide active cathode materials for use in alkaline rechargeable batteries are capable of transferring >1.3 electrons per Ni atom under reversible electrochemical conditions. The specific capacity of the nickel hydroxide active materials is for example .gtoreq.325 mAh/g. The cathode active materials exhibit an additional discharge plateau near 0.8 V vs. a metal hydride (MH) anode. Ni in an oxidation state of less than 2, such as Ni.sup.1+, is able to participate in electrochemical reactions when using the present cathode active materials. It is possible that up to 2.3 electrons, up to 2.5 electrons or more may be transferred per Ni atom under electrochemical conditions.

  6. Methotrexate intercalated ZnAl-layered double hydroxide

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Chakraborty, Manjusha; Dasgupta, Sudip; Soundrapandian, Chidambaram

    2011-09-15

    The anticancerous drug methotrexate (MTX) has been intercalated into an ZnAl-layered double hydroxide (LDH) using an anion exchange technique to produce LDH-MTX hybrids having particle sizes in the range of 100-300 nm. X-ray diffraction studies revealed increases in the basal spacings of ZnAl-LDH-MTX hybrid on MTX intercalation. This was corroborated by the transmission electron micrographs, which showed an increase in average interlayer spacing from 8.9 A in pristine LDH to 21.3 A in LDH-MTX hybrid. Thermogravimetric analyses showed an increase in the decomposition temperature for the MTX molecule in the LDH-MTX hybrid indicating enhanced thermal stability of the drug moleculemore » in the LDH nanovehicle. The cumulative release profile of MTX from ZnAl-LDH-MTX hybrids in phosphate buffer saline (PBS) at pH 7.4 was successfully sustained for 48 h following Rigter-Peppas model release kinetics via diffusion. - Graphical abstract: ZnAl-layered double hydroxide intercalated with methotrexate ({approx}34% loading) promises the possibility of use of ZnAl-LDH material as drug carrier and in controlled delivery. Highlights: > ZnAl-layered double hydroxide methotrexate nanohybrid has been synthesized. > XRD and TEM studies on nanohybrid revealed successful intercalation of methotrexate. > TG and CHN analyses showed {approx}34 wt% of methotrexate loading into the nanohybrid. > Possibility of use of ZnAl-LDH material as drug carrier and in delivery.« less

  7. Tracing the history of submarine hydrothermal inputs and the significance of hydrothermal hafnium for the seawater budget - A combined Pb-Hf-Nd isotope approach

    USGS Publications Warehouse

    van de Flierdt, T.; Frank, M.; Halliday, A.N.; Hein, J.R.; Hattendorf, B.; Gunther, D.; Kubik, P.W.

    2004-01-01

    Secular variations in the Pb isotopic composition of a mixed hydrogenous-hydrothermal ferromanganese crust from the Bauer Basin in the eastern Equatorial Pacific provide clear evidence for changes in hydrothermal contributions during the past 7 Myr. The nearby Galapagos Rise spreading center provided a strong hydrothermal flux prior to 6.5 Ma. After 6.5 Ma, the Pb became stepwise more radiogenic and more similar to Equatorial Pacific seawater, reflecting the westward shift of spreading to the presently active East Pacific Rise (EPR). A second, previously unrecognized enhanced hydrothermal period occurred between 4.4 and 2.9 Ma, which reflects either off-axis hydrothermal activity in the Bauer Basin or a late-stage pulse of hydrothermal Pb from the then active, but waning Galapagos Rise spreading center. Hafnium isotope time-series of the same mixed hydrogenous-hydrothermal crust show invariant values over the past 7 Myr. Hafnium isotope ratios, as well as Nd isotope ratios obtained for this crust, are identical to that of hydrogenous Equatorial Pacific deep water crusts and clearly indicate that hydrothermal Hf, similar to Nd, does not travel far from submarine vents. Therefore, we suggest that hydrothermal Hf fluxes do not contribute significantly to the global marine Hf budget. ?? 2004 Elsevier B.V. All rights reserved.

  8. Ionic substitution of Mg2+ for Al3+ and Fe3+ with octahedral coordination in hydroxides facilitate precipitation of layered double hydroxides

    NASA Astrophysics Data System (ADS)

    Paikaray, Susanta; Essilfie-Dughan, Joseph; Hendry, M. Jim

    2018-01-01

    Precipitation of hydrotalcite-like layered double hydroxides (HT-LDHs) from CO32--SO42--rich acidic and alkaline aqueous media through ionic substitution of Mg2+ for Al3+ + Fe3+ and vice versa was investigated under ambient conditions. Diffractogram, spectroscopic, microprobe, microscopic, and synchrotron techniques were used to examine the mechanisms involved. The cations facilitated rapid precipitation of HT-LDH in alkaline conditions (pH ≥ 8.2) with SO42- and CO32- as the counter charge balancing interlayer anions, while initial formation of Fe3+- and Al3+-hydroxides in acidic conditions (pH ≥ 2.4) with subsequent transformation to MgAlFe-type HT-LDH (pH ≥ 8.2) occurred through substitution of Mg2+ for Al3+ and Fe3+. Substitution of Al3+ and Fe3+ in Mg2+-hydroxides did not yield HT-LDH, while the reverse, i.e., Mg2+ substitution in Al3+ and Fe3+-hydroxides, produced initial poorly ordered amorphous HT-LDH that gained better crystallinity and crystallite size upon neutralization. Linear combination fit analyses of XANES data suggest schwertmannite constituted the predominant Fe-phase until pH ∼3.7 followed by ferrihydrite and eventually HT-LDH after pH ≥ 10; basaluminite and epsomite constituted the predominant Al and Mg phases until pH ∼4.5, after which HT-LDH with minor Al(OH)3 and HT-LDH with brucite, respectively, predominated. The study highlights that Mg2+ substitution in Al- and Fe-precipitates is the governing mechanism for HT-LDH precipitation in oxic environments through neutralization of acidic cationic aqueous residues.

  9. BIOGEOCHEMICAL PROCESSES CONTROLLING ARSENIC SPECIATION AND BIOTRANSFORMATION IN GRANULAR FERRIC HYDROXIDE COATED SAND

    EPA Science Inventory

    Arsenic mobilization from solid phase Fe (III) hydroxides is an issue of concern, as water-borne arsenic can migrate into pristine environments, endangering aquatic and human life. In general, metal oxide (hydroxides) exerts a dominating effect on the fate and transport of arseni...

  10. Structure of bayerite-based lithium-aluminum layered double hydroxides (LDHs): observation of monoclinic symmetry.

    PubMed

    Britto, Sylvia; Kamath, P Vishnu

    2009-12-21

    The double hydroxides of Li with Al, obtained by the imbibition of Li salts into bayerite and gibbsite-Al(OH)(3), are not different polytypes of the same symmetry but actually crystallize in two different symmetries. The bayerite-derived double hydroxides crystallize with monoclinic symmetry, while the gibbsite-derived hydroxides crystallize with hexagonal symmetry. Successive metal hydroxide layers in the bayerite-derived LDHs are translated by the vector ( approximately -1/3, 0, 1) with respect to each other. The exigency of hydrogen bonding drives the intercalated Cl(-) ion to a site with 2-fold coordination, whereas the intercalated water occupies a site with 6-fold coordination having a pseudotrigonal prismatic symmetry. The nonideal nature of the interlayer sites has implications for the observed selectivity of Li-Al LDHs toward anions of different symmetries.

  11. Low-voltage high-performance organic thin film transistors with a thermally annealed polystyrene/hafnium oxide dielectric

    NASA Astrophysics Data System (ADS)

    Wang, Ying; Acton, Orb; Ting, Guy; Weidner, Tobias; Ma, Hong; Castner, David G.; Jen, Alex K.-Y.

    2009-12-01

    Low-voltage pentacene-based organic thin film transistors (OTFTs) are demonstrated with polystyrene (PS)/hafnium oxide (HfOx) hybrid dielectrics. Thermal annealing of PS films on HfOx at 120 °C (PS-120) induces a flatter orientation of the phenyl groups (tilt angle 65°) at the surface compared to PS films without annealing (PS-RT) (tilt angle 31°). The flatter phenyl group orientation leads to better matching of surface energy between pentacene and PS. Pentacene deposited on PS-120 display higher quality thin films with larger grain sizes and higher crystallinity. Pentacene OTFTs with PS-120/HfOx hybrid dielectrics can operate at low-voltage (<3 V) with high field-effect mobilities (1 cm2/V s), high on/off current ratios (106), and low subthreshold slopes (100 mV/dec).

  12. Plasma graft-polymerization for synthesis of highly stable hydroxide exchange membrane

    NASA Astrophysics Data System (ADS)

    Hu, Jue; Zhang, Chengxu; Jiang, Lin; Fang, Shidong; Zhang, Xiaodong; Wang, Xiangke; Meng, Yuedong

    2014-02-01

    A novel plasma graft-polymerization approach is adopted to prepare hydroxide exchange membranes (HEMs) using cardo polyetherketone powders (PEK-C) and vinylbenzyl chloride. The benzylic chloromethyl groups can be successfully introduced into the PEK-C polymer matrix via plasma graft-polymerization. This approach enables a well preservation in the structure of functional groups and formation of a highly cross-linked structure in the membrane, leading to an improvement on the stability and performance of HEMs. The chemical stabilities, including alkaline and oxidative stability, are evaluated under severe conditions by measuring hydroxide conductivity and weight changes during aging. The obtained PGP-NOH membrane retains 86% of the initial hydroxide conductivity in 6 mol L-1 KOH solution at 60 °C for 120 h, and 94% of the initial weight in 3 wt% H2O2 solution at 60 °C for 262 h. The PGP-NOH membrane also possesses excellent thermal stability (safely used below 120 °C), alcohol resistance (ethanol permeability of 6.6 × 10-11 m2 s-1 and diffusion coefficient of 3.7 × 10-13 m2 s-1), and an acceptable hydroxide conductivity (8.3 mS cm-1 at 20 °C in deionized water), suggesting a good candidate of PGP-NOH membrane for HEMFC applications.

  13. Passivation of InP heterojunction bipolar transistors by strain controlled plasma assisted electron beam evaporated hafnium oxide

    NASA Astrophysics Data System (ADS)

    Driad, R.; Sah, R. E.; Schmidt, R.; Kirste, L.

    2012-01-01

    We present structural, stress, and electrical properties of plasma assisted e-beam evaporated hafnium dioxide (HfO2) layers on n-type InP substrates. These layers have subsequently been used for surface passivation of InGaAs/InP heterostructure bipolar transistors either alone or in combination with plasma enhanced chemical vapor deposited SiO2 layers. The use of stacked HfO2/SiO2 results in better interface quality with InGaAs/InP heterostructures, as illustrated by smaller leakage current and improved breakdown voltage. These improvements can be attributed to the reduced defect density and charge trapping at the dielectric-semiconductor interface. The deposition at room temperature makes these films suitable for sensitive devices.

  14. Recycling Lithium Carbonate/Lithium Hydroxide Waste

    NASA Technical Reports Server (NTRS)

    Flowers, J.; Flowers, J.

    1983-01-01

    Hazardous waste disposal problem eliminated by regeneration. Li2CO3/ LiOH recycling process relies on low solubility of alkali carbonates in corresponding hydroxides. Li2CO3 precipitate calcined to LI2O, then rehydrated LiOH. Regeneration eliminates need to dispose caustic waste and uses less energy than simple calcination of entire waste mass.

  15. 21 CFR 184.1631 - Potassium hydroxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... thickener as defined in § 170.3(o)(28) of this chapter. (2) The ingredient is used in food at levels not to... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Potassium hydroxide. 184.1631 Section 184.1631 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD...

  16. 21 CFR 184.1631 - Potassium hydroxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... thickener as defined in § 170.3(o)(28) of this chapter. (2) The ingredient is used in food at levels not to... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Potassium hydroxide. 184.1631 Section 184.1631 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR...

  17. Apical closure of mature molar roots with the use of calcium hydroxide.

    PubMed

    Rotstein, I; Friedman, S; Katz, J

    1990-11-01

    Calcium hydroxide may induce apical root closure in affected mature teeth as well as in immature teeth. Once an apical hard tissue barrier is formed, a permanent root canal filling can be safely condensed. Two cases are described in which calcium hydroxide induced apical root closure in mature molar teeth where the apical constriction was lost because of chronic inflammatory process.

  18. Kinetics of de-N-acetylation of the chitin disaccharide in aqueous sodium hydroxide solution.

    PubMed

    Khong, Thang Trung; Aachmann, Finn L; Vårum, Kjell M

    2012-05-01

    Chitosan is prepared from chitin, a process which is carried out at highly alkaline conditions, and that can be performed either on chitin in solution (homogeneous deacetylation) or heterogeneously with the chitin as a solid throughout the reaction. We report here a study of the de-N-acetylation reaction of the chitin dimer (GlcNAc-GlcNAc) in solution. The reaction was followed by (1)H NMR spectroscopy in deuterated aqueous sodium hydroxide solution as a function of time, sodium-hydroxide concentration and temperature. The (1)H NMR spectrum of GlcNAc-GlcNAc in 2.77 M deuterated aqueous sodium hydroxide solution was assigned. The interpretation of the (1)H NMR spectra allowed us to determine the rates of de-N-acetylation of the reducing and non-reducing ends, showing that the reaction rate at the reducing end is twice the rate at the non-reducing end. The total deacetylation reaction rate was determined as a function of the hydroxide ion concentration, showing for the first time that this de-N-acetylation reaction is second order with respect to hydroxide ion concentration. No significant difference in the deacetylation rates in deuterated water compared to water was observed. The activation energy for the reaction (26-54 °C) was determined to 114.4 and 98.6 kJ/mol at 2.77 and 5.5 M in deuterated aqueous sodium hydroxide solution, respectively. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Automated solid-phase extraction of phenolic acids using layered double hydroxide-alumina-polymer disks.

    PubMed

    Ghani, Milad; Palomino Cabello, Carlos; Saraji, Mohammad; Manuel Estela, Jose; Cerdà, Víctor; Turnes Palomino, Gemma; Maya, Fernando

    2018-01-26

    The application of layered double hydroxide-Al 2 O 3 -polymer mixed-matrix disks for solid-phase extraction is reported for the first time. Al 2 O 3 is embedded in a polymer matrix followed by an in situ metal-exchange process to obtain a layered double hydroxide-Al 2 O 3 -polymer mixed-matrix disk with excellent flow-through properties. The extraction performance of the prepared disks is evaluated as a proof of concept for the automated extraction using sequential injection analysis of organic acids (p-hydroxybenzoic acid, 3,4-dihydroxybenzoic acid, gallic acid) following an anion-exchange mechanism. After the solid-phase extraction, phenolic acids were quantified by reversed-phase high-performance liquid chromatography with diode-array detection using a core-shell silica-C18 stationary phase and isocratic elution (acetonitrile/0.5% acetic acid in pure water, 5:95, v/v). High sensitivity and reproducibility were obtained with limits of detection in the range of 0.12-0.25 μg/L (sample volume, 4 mL), and relative standard deviations between 2.9 and 3.4% (10 μg/L, n = 6). Enrichment factors of 34-39 were obtained. Layered double hydroxide-Al 2 O 3 -polymer mixed-matrix disks had an average lifetime of 50 extractions. Analyte recoveries ranged from 93 to 96% for grape juice and nonalcoholic beer samples. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Electrodeposition of Zn-doped α-nickel hydroxide with flower-like nanostructure for supercapacitors

    NASA Astrophysics Data System (ADS)

    You, Zheng; Shen, Kui; Wu, Zhicheng; Wang, Xiaofeng; Kong, Xianghua

    2012-08-01

    Zn-doped α-nickel hydroxide materials with flower-like nanostructures are synthesized by electrochemical deposition method. The samples are characterized by X-ray diffraction (XRD), field emission scanning electron microscope (SEM) and electrochemical measurements. XRD spectra indicate nickel hydroxide doped with Zn is α-Ni(OH)2 with excellent crystallization. The SEM observation shows that the formation of Zn-doped Ni(OH)2 includes two steps: a honeycomb-like film forms on the substrate first, then flower-like particles forms on the films. The nickel hydroxide doped with 5% Zn can maintain a maximum specific capacitance of 860 F g-1, suggesting its potential application in electrochemical capacitors.

  1. Structural Differentiation between Layered Single (Ni) and Double Metal Hydroxides (Ni–Al LDHs) Using Wavelet Transformation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Siebecker, Matthew G.; Sparks, Donald L.

    2017-09-07

    Layered double hydroxides (LDHs) are anionic clays important in disciplines such as environmental chemistry, geochemistry, and materials science. Developments in signal processing of extended X-ray absorption fine structure (EXAFS) data, such as wavelet transformation (WT), have been used to identify transition metals and Al present in the hydroxide sheets of LDHs. The WT plots of LDHs should be distinct from those of isostructural single metal hydroxides. However, no direct comparison of these minerals appears in the literature using WT. This work systematically analyzes a suite of Ni-rich mineral standards, including Ni–Al LDHs, single metal Ni hydroxides, and Ni-rich silicates usingmore » WT. The results illustrate that the WT plots for α-Ni(OH)2 and Ni–Al LDHs are often indistinguishable from each other, with similar two-component plots for the different mineral types. This demonstrates that the WT of the first metal shell often cannot be used to differentiate an LDH from a single metal hydroxide. Interlayer anions adsorbed to the hydroxide sheet of α-Ni(OH)2 affect the EXAFS spectra and are not visible in the FT but are clearly resolved and discrete in the WT.« less

  2. Cesium hafnium chloride: A high light yield, non-hygroscopic cubic crystal scintillator for gamma spectroscopy

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Burger, Arnold, E-mail: aburger@fisk.edu; Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235; Rowe, Emmanuel

    We report on the scintillation properties of Cs{sub 2}HfCl{sub 6} (cesium hafnium chloride or CHC) as an example of a little-known class of non-hygroscopic compounds having the generic cubic crystal structure of K{sub 2}PtCl{sub 6}. The crystals are easily growable from the melt using the Bridgman method with minimal precursor treatments or purification. CHC scintillation is centered at 400 nm, with a principal decay time of 4.37 μs and a light yield of up to 54 000 photons/MeV when measured using a silicon CCD photodetector. The light yield is the highest ever reported for an undoped crystal, and CHC also exhibits excellent lightmore » yield nonproportionality. These desirable properties allowed us to build and test CHC gamma-ray spectrometers providing energy resolution of 3.3% at 662 keV.« less

  3. Hydroxide Self-Feeding High-Temperature Alkaline Direct Formate Fuel Cells.

    PubMed

    Li, Yinshi; Sun, Xianda; Feng, Ying

    2017-05-22

    Conventionally, both the thermal degradation of the anion-exchange membrane and the requirement of additional hydroxide for fuel oxidation reaction hinder the development of the high-temperature alkaline direct liquid fuel cells. The present work addresses these two issues by reporting a polybenzimidazole-membrane-based direct formate fuel cell (DFFC). Theoretically, the cell voltage of the high-temperature alkaline DFFC can be as high as 1.45 V at 90 °C. It has been demonstrated that a proof-of-concept alkaline DFFC without adding additional hydroxide yields a peak power density of 20.9 mW cm -2 , an order of magnitude higher than both alkaline direct ethanol fuel cells and alkaline direct methanol fuel cells, mainly because the hydrolysis of formate provides enough OH - ions for formate oxidation reaction. It was also found that this hydroxide self-feeding high-temperature alkaline DFFC shows a stable 100 min constant-current discharge at 90 °C, proving the conceptual feasibility. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Effects of adhesions of amorphous Fe and Al hydroxides on surface charge and adsorption of K+ and Cd2+ on rice roots.

    PubMed

    Liu, Zhao-Dong; Wang, Hai-Cui; Zhou, Qin; Xu, Ren-Kou

    2017-11-01

    Iron (Fe) and aluminum (Al) hydroxides in variable charge soils attached to rice roots may affect surface-charge properties and subsequently the adsorption and uptake of nutrients and toxic metals by the roots. Adhesion of amorphous Fe and Al hydroxides onto rice roots and their effects on zeta potential of roots and adsorption of potassium (K + ) and cadmium (Cd 2+ ) by roots were investigated. Rice roots adsorbed more Al hydroxide than Fe hydroxide because of the greater positive charge on Al hydroxide. Adhesion of Fe and Al hydroxides decreased the negative charge on rice roots, and a greater effect of the Al hydroxide. Consequently, adhesion of Fe and Al hydroxides reduced the K + and Cd 2+ adsorption by rice roots. The results of attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and desorption of K + and Cd 2+ from rice roots indicated that physical masking by Fe and Al hydroxides and diffuse-layer overlapping between the positively-charged hydroxides and negatively-charged roots were responsible for the reduction of negative charge on roots induced by adhesion of the hydroxides. Therefore, the interaction between Fe and Al hydroxides and rice roots reduced negative charge on roots and thus inhibited their adsorption of nutrient and toxic cations. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Influence of calcium hydroxide on the post-treatment pain in Endodontics: A systematic review

    PubMed Central

    Anjaneyulu, K.; Nivedhitha, Malli Sureshbabu

    2014-01-01

    Introduction: Pain of endodontic origin has been a major concern to the patients and the clinicians for many years. Post-operative pain is associated with inflammation in the periradicular tissues caused by irritants egressing from root canal during treatment. It has been suggested that calcium hydroxide intra-canal medicament has pain-preventive properties because of its anti-microbial or tissue altering effects. Some dispute this and reasoned that calcium hydroxide may initiate or increase pain by inducing or increasing inflammation. Objective: To evaluate the effectiveness of calcium hydroxide in reducing the post-treatment pain when used as an intra-canal medicament Materials and Methods: The following databases were searched: PubMed CENTRAL (until July 2013), MEDLINE, and Cochrane Database of Systematic Reviews. Bibliographies of clinical studies and reviews identified in the electronic search were analyzed for studies published outside the electronically searched journals. The primary outcome measure was to evaluate the post-treatment pain reduction when calcium hydroxide is used as an intra-canal medicament in patients undergoing root canal therapy. Results: The reviews found some clinical evidence that calcium hydroxide is not very effective in reducing post-treatment pain when it is used alone, but its effectiveness can be increased when used in combination with other medicaments like chlorhexidine and camphorated monochlorophenol (CMCP). Conclusion: Even though calcium hydroxide is one of the most widely used intra-canal medicament due to its anti-microbial properties, there is no clear evidence of its effect on the post-treatment pain after the chemo-mechanical root canal preparation. PMID:24944439

  6. Effect of ferric hydroxide suspension on blood chemstry in the common shiner, Notropus cornutus

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Brenner, F.J.; Corbett, S.; Shertzer, R.

    1976-05-01

    Common shiners, Notropus cornutus, were exposed to 3 ppM ferric hydroxide for periods from two to eight weeks. Ferric hydroxide resulted in initial changes in serum protein, glucose, Na and K ions, but these changes did not adversely affect the internal dynamics of the fish.

  7. Antimycobacterial, antimicrobial, and biocompatibility properties of para-aminosalicylic acid with zinc layered hydroxide and Zn/Al layered double hydroxide nanocomposites

    PubMed Central

    Saifullah, Bullo; El Zowalaty, Mohamed E; Arulselvan, Palanisamy; Fakurazi, Sharida; Webster, Thomas J; Geilich, Benjamin M; Hussein, Mohd Zobir

    2014-01-01

    The treatment of tuberculosis by chemotherapy is complicated due to multiple drug prescriptions, long treatment duration, and adverse side effects. We report here for the first time an in vitro therapeutic effect of nanocomposites based on para-aminosalicylic acid with zinc layered hydroxide (PAS-ZLH) and zinc-aluminum layered double hydroxides (PAS-Zn/Al LDH), against mycobacteria, Gram-positive bacteria, and Gram-negative bacteria. The nanocomposites demonstrated good antimycobacterial activity and were found to be effective in killing Gram-positive and Gram-negative bacteria. A biocompatibility study revealed good biocompatibility of the PAS-ZLH nanocomposites against normal human MRC-5 lung cells. The para-aminosalicylic acid loading was quantified with high-performance liquid chromatography analysis. In summary, the present preliminary in vitro studies are highly encouraging for further in vivo studies of PAS-ZLH and PAS-Zn/Al LDH nanocomposites to treat tuberculosis. PMID:25114509

  8. Synthesis and characterization of α-cobalt hydroxide nanobelts

    NASA Astrophysics Data System (ADS)

    Tian, L.; Zhu, J. L.; Chen, L.; An, B.; Liu, Q. Q.; Huang, K. L.

    2011-08-01

    α-Cobalt hydroxide was synthesized by a facile hydrothermal process from Co(Ac)2 and NH3·H2O in the presence of 1,3-propanediol. The large-scale-prepared cobalt hydroxide has a uniform nanobelt morphology with a considerably high aspect-ratio more than 20 which may be advantageous for exploration of their physicochemical properties. This synthetic method is convenient, economical, and controllable. The samples were characterized by powder X-ray diffraction, energy dispersive spectrum, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, CHN element analysis, thermogravimetric and differential-thermogravimetric analysis, which revealed the compound is lamellar structural cobalt organic-inorganic hybrid with the chemical formula of Co(OH)1.49(NH3)0.01(CO3 2-)0.22(Ac-)0.07(H2O)0.11 and single-crystalline.

  9. Hierarchical cobalt-based hydroxide microspheres for water oxidation.

    PubMed

    Zhang, Ye; Cui, Bai; Derr, Olivia; Yao, Zhibo; Qin, Zhaotong; Deng, Xiangyun; Li, Jianbao; Lin, Hong

    2014-03-21

    3D hierarchical cobalt hydroxide carbonate hydrate (Co(CO3)0.5(OH)·0.11H2O) has been synthesized featuring a hollow urchin-like structure by a one-step hydrothermal method at modest temperature on FTO glass substrates. The functionalities of precursor surfactants were isolated and analyzed. A plausible formation mechanism of the spherical urchin-like microclusters has been furnished through time-dependent investigations. Introduction of other transitional metal doping (Cu, Ni) would give rise to a substantial morphological change associated with a surface area drop. The directly grown cobalt-based hydroxide composite electrodes were found to be capable of catalyzing oxygen evolution reaction (OER) under both neutral pH and alkaline conditions. The favorable 3D dendritic morphology and porous structure provide large surface areas and possible defect sites that are likely responsible for their robust electrochemical activity.

  10. Aluminum affects heterogeneous Fe(III) (Hydr)oxide nucleation, growth, and ostwald ripening.

    PubMed

    Hu, Yandi; Li, Qingyun; Lee, Byeongdu; Jun, Young-Shin

    2014-01-01

    Heterogeneous coprecipitation of iron and aluminum oxides is an important process for pollutant immobilization and removal in natural and engineered aqueous environments. Here, using a synchrotron-based small-angle X-ray scattering technique, we studied heterogeneous nucleation and growth of Fe(III) (hydr)oxide on quartz under conditions found in acid mine drainage (at pH = 3.7 ± 0.2, [Fe(3+)] = 10(-4) M) with different initial aqueous Al/Fe ratios (0:1, 1:1, and 5:1). Interestingly, although the atomic ratios of Al/Fe in the newly formed Fe(III) (hydr)oxide precipitates were less than 1%, the in situ particle size and volume evolutions of the precipitates on quartz were significantly influenced by aqueous Al/Fe ratios. At the end of the 3 h experiments, with aqueous Al/Fe ratios of 0:1, 1:1, and 5:1, the average radii of gyration of particles on quartz were 5.7 ± 0.3, 4.6 ± 0.1, and 3.7 ± 0.3 nm, respectively, and the ratio of total particle volumes on quartz was 1.7:3.4:1.0. The Fe(III) (hydr)oxide precipitates were poorly crystallized, and were positively charged in all solutions. In the presence of Al(3+), Al(3+) adsorption onto quartz changed the surface charge of quartz from negative to positive, which caused the slower heterogeneous growth of Fe(III) (hydr)oxide on quartz. Furthermore, Al affected the amount of water included in the Fe(III) (hydr)oxides, which can influence their adsorption capacity. This study yielded important information usable for pollutant removal not only in natural environments, but also in engineered water treatment processes.

  11. A Comparative Study of Ion Diffusion from Calcium Hydroxide with Various Herbal Pastes through Dentin

    PubMed Central

    Dhirawani, Rajesh B; Marya, Jayant; Dhirawani, Vrinda; Kumar, Vijayendra

    2017-01-01

    Aim The aim of this study was to evaluate the diffusion ability of ions through dentinal tubules of different nonalcoholic calcium hydroxide-containing herbal pastes and compare it with the calcium hydroxide paste prepared with saline. Materials and methods A total of 36 single-rooted premolar teeth were used in this study. The tooth crowns were removed and the root canals were prepared. Depending on the vehicle to be used for preparing calcium hydroxide pastes, six groups were made: Group I: Ca(OH)2 saline paste (control group), group II: Ca(OH)2 papaya latex paste, group III: Ca(OH)2 coconut water paste, group IV: Ca(OH)2 Ashwagandha (Withania somnifera) paste, group V: Ca(OH)2 Tulsi (Ocimum tenuiflorum) paste, and group VI: Ca(OH)2 garlic (Allium sativum) paste. After biomechanical preparation, calcium hydroxide herbal paste dressings were applied and sealed with resin-based cement. The teeth were placed in containers with deionized water, and the pH of the water was measured at regular intervals over 3, 24, 72, and 168 hours. Results We observed that all herbal pastes allowed the diffusion of ions, but pastes prepared with Ashwagandha and papaya latex showed more ion diffusion after 168 hours and marked increase in pH, depicting better support for calcium hydroxide action. Conclusion We conclude that Ashwagandha and papaya latex allow better diffusion of calcium hydroxide through den-tinal tubules, thus enhancing its action, and advise its use as a vehicle for placing intracanal medicament. How to cite this article Dausage P, Dhirawani RB, Marya J, Dhirawani V, Kumar V. A Comparative Study of Ion Diffusion from Calcium Hydroxide with Various Herbal Pastes through Dentin. Int J Clin Pediatr Dent 2017;10(1):41-44. PMID:28377654

  12. Hydroxide based Benzyltrimethylammonium degradation: Quantification of rates and degradation technique development

    DOE PAGES

    Sturgeon, Matthew R.; Macomber, Clay S.; Engtrakul, Chaiwat; ...

    2015-01-21

    Anion exchange membranes (AEMs) are of interest as hydroxide conducting polymer electrolytes in electrochemical devices like fuel cells and electrolyzers. AEMs require hydroxide stable covalently tetherable cations to ensure required conductivity. Benzyltrimethylammonium (BTMA) has been the covalently tetherable cation that has been most often employed in anion exchange membranes because it is reasonably basic, compact (limited number of atoms per charge), and easily/cheaply synthesized. Several reports exist that have investigated hydroxide stability of BTMA under specific conditions, but consistency within these reports and comparisons between them have not yet been made. While the hydroxide stability of BTMA has been believedmore » to be a limitation for AEMs, this stability has not been thoroughly reported. In this paper, we have found that several methods reported have inherent flaws in their findings due to the difficulty of performing degradation experiments at high temperature and high pH. In order to address these shortcomings, we have developed a reliable, standardized method of determining cation degradation under conditions similar/relevant to those expected in electrochemical devices. The experimental method has been employed to determine BTMA stabilities at varying cation concentrations and elevated temperatures, and has resulted in improved experimental accuracy and reproducibility. Finally and most notably, these results have shown that BTMA is quite stable at 80°C (half-life of ~4 years), a significant increase in stability over what had been reported previously.« less

  13. Sorption of sodium hydroxide by type I collagen and bovine corneas.

    PubMed

    Whikehart, D R; Edwards, W C; Pfister, R R

    1991-01-01

    There are no quantitative studies on the uptake of alkali into corneal tissues. To study this phenomenon, both type I collagen and bovine corneas were incubated in sodium hydroxide (NaOH) under varying conditions for periods up to 27.5 h. The sorption (absorption or adsorption) of the alkali to protein and tissue was measured as the quantity of NaOH no longer available for titration to neutrality with hydrochloric acid. Sorption was found to be dependent on the concentration of NaOH (0.01-1 N) but independent of the incubation temperature (4-35 degrees C). In whole cornea, sorption of 1 N NaOH began immediately and increased with time up to 6 h. After 6 h, sorption decreased, together with the observed degradation and solubilization of the tissue. Stripping of the corneal endothelium alone or of the endothelium and epithelium increased sorption in a similar manner when compared to whole corneas for periods up to 4 h. These observations are compatible with ionic and nonionic bonding of hydroxide ions to collagen (including that of the cornea) and the subsequent release of hydroxide ions during hydrolysis of the protein itself. Indirect evidence also suggests the inclusion of quantities of unbound hydroxide ions in hydrated gels of glycosaminoglycans. It is proposed that in a chemical burn of the cornea, alkali is both stored in the tissue (by sorption) and reacted with it (by hydrolysis), without any net consumption of alkali taking place.

  14. Isolation of tungsten and tantalum isotopes without supports from. cap alpha. -particle-irradiated hafnium targets

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gasita, S.M.; Iota, B.Z.; Malachkov, A.G.

    1985-11-01

    An extraction procedure has been developed for successive isolation of tungsten (/sup 178/W and /sup 181/W) and tantalum (/sup 179/Ta and /sup 182/Ta) isotopes without supports from ..cap alpha..particle-irradiated hafnium targets. The target, irradiated on a cyclotron, is dissolved in hydrofluoric acid. Tantalum isotopes are extracted with tributyl phosphate (TBP) from 1-5 M HF and are then reextracted with a 1:1 ammonia solution, and hydrofluoric acid is removed by heating. Tungsten isotopes are extracted with a chloroform solution or N-benzoyl-N-phenylhydroxylamine (BPHA) from 11-12 M H/sub 2/SO/sub 4/ or ..cap alpha..-benzoin oxime from 4.5-5.5 M H/sub 2/SO/sub 4/ and are thenmore » reextracted with a l:l ammonia solution. The yield of tungsten isotopes is not less than 95%, and the content of radioactive impurities of other isotopes is not more than 0.1%.« less

  15. 21 CFR 73.2326 - Chromium hydroxide green.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Chromium hydroxide green. 73.2326 Section 73.2326 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF... in coloring externally applied cosmetics, including those intended for use in the area of the eye, in...

  16. 21 CFR 73.2326 - Chromium hydroxide green.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Chromium hydroxide green. 73.2326 Section 73.2326 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF... in coloring externally applied cosmetics, including those intended for use in the area of the eye, in...

  17. Tailoring transition-metal hydroxides and oxides by photon-induced reactions

    DOE PAGES

    Niu, Kai -Yang; Fang, Liang; Ye, Rong; ...

    2016-10-18

    Controlled synthesis of transition-metal hydroxides and oxides with earth-abundant elements have attracted significant interest because of their wide applications, for example as battery electrode materials or electrocatalysts for fuel generation. Here, we report the tuning of the structure of transition-metal hydroxides and oxides by controlling chemical reactions using an unfocused laser to irradiate the precursor solution. A Nd:YAG laser with wavelengths of 532 nm or 1064 nm was used. The Ni 2+, Mn 2+, and Co 2+ ion-containing aqueous solution undergoes photo-induced reactions and produces hollow metal-oxide nanospheres (Ni 0.18Mn 0.45Co 0.37O x) or core–shell metal hydroxide nanoflowers ([Ni 0.15Mnmore » 0.15Co 0.7(OH) 2](NO 3) 0.2•H 2O), depending on the laser wavelengths. We propose two reaction pathways, either by photo-induced redox reaction or hydrolysis reaction, which are responsible for the formation of distinct nanostructures. As a result, the study of photon-induced materials growth shines light on the rational design of complex nanostructures with advanced functionalities.« less

  18. Development of Drug Delivery Systems Based on Layered Hydroxides for Nanomedicine

    PubMed Central

    Barahuie, Farahnaz; Hussein, Mohd Zobir; Fakurazi, Sharida; Zainal, Zulkarnain

    2014-01-01

    Layered hydroxides (LHs) have recently fascinated researchers due to their wide application in various fields. These inorganic nanoparticles, with excellent features as nanocarriers in drug delivery systems, have the potential to play an important role in healthcare. Owing to their outstanding ion-exchange capacity, many organic pharmaceutical drugs have been intercalated into the interlayer galleries of LHs and, consequently, novel nanodrugs or smart drugs may revolutionize in the treatment of diseases. Layered hydroxides, as green nanoreservoirs with sustained drug release and cell targeting properties hold great promise of improving health and prolonging life. PMID:24802876

  19. Hydrated proton and hydroxide charge transfer at the liquid/vapor interface of water

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Soniat, Marielle; Rick, Steven W., E-mail: srick@uno.edu; Kumar, Revati

    2015-07-28

    The role of the solvated excess proton and hydroxide ions in interfacial properties is an interesting scientific question with applications in a variety of aqueous behaviors. The role that charge transfer (CT) plays in interfacial behavior is also an unsettled question. Quantum calculations are carried out on clusters of water with an excess proton or a missing proton (hydroxide) to determine their CT. The quantum results are applied to analysis of multi-state empirical valence bond trajectories. The polyatomic nature of the solvated excess proton and hydroxide ion results in directionally dependent CT, depending on whether a water molecule is amore » hydrogen bond donor or acceptor in relation to the ion. With polyatomic molecules, CT also depends on the intramolecular bond distances in addition to intermolecular distances. The hydrated proton and hydroxide affect water’s liquid/vapor interface in a manner similar to monatomic ions, in that they induce a hydrogen-bonding imbalance at the surface, which results in charged surface waters. This hydrogen bond imbalance, and thus the charged waters at the surface, persists until the ion is at least 10 Å away from the interface.« less

  20. Formation of iron (hydr)oxides during the abiotic oxidation of Fe(II) in the presence of arsenate.

    PubMed

    Song, Jia; Jia, Shao-Yi; Yu, Bo; Wu, Song-Hai; Han, Xu

    2015-08-30

    Abiotic oxidation of Fe(II) is a common pathway in the formation of Fe (hydr)oxides under natural conditions, however, little is known regarding the presence of arsenate on this process. In hence, the effect of arsenate on the precipitation of Fe (hydr)oxides during the oxidation of Fe(II) is investigated. Formation of arsenic-containing Fe (hydr)oxides is constrained by pH and molar ratios of As:Fe during the oxidation Fe(II). At pH 6.0, arsenate inhibits the formation of lepidocrocite and goethite, while favors the formation of ferric arsenate with the increasing As:Fe ratio. At pH 7.0, arsenate promotes the formation of hollow-structured Fe (hydr)oxides containing arsenate, as the As:Fe ratio reaches 0.07. Arsenate effectively inhibits the formation of magnetite at pH 8.0 even at As:Fe ratio of 0.01, while favors the formation of lepidocrocite and green rust, which can be latterly degenerated and replaced by ferric arsenate with the increasing As:Fe ratio. This study indicates that arsenate and low pH value favor the slow growth of dense-structured Fe (hydr)oxides like spherical ferric arsenate. With the rapid oxidation rate of Fe(II) at high pH, ferric (hydr)oxides prefer to precipitate in the formation of loose-structured Fe (hydr)oxides like lepidocrocite and green rust. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Protons and Hydroxide Ions in Aqueous Systems.

    PubMed

    Agmon, Noam; Bakker, Huib J; Campen, R Kramer; Henchman, Richard H; Pohl, Peter; Roke, Sylvie; Thämer, Martin; Hassanali, Ali

    2016-07-13

    Understanding the structure and dynamics of water's constituent ions, proton and hydroxide, has been a subject of numerous experimental and theoretical studies over the last century. Besides their obvious importance in acid-base chemistry, these ions play an important role in numerous applications ranging from enzyme catalysis to environmental chemistry. Despite a long history of research, many fundamental issues regarding their properties continue to be an active area of research. Here, we provide a review of the experimental and theoretical advances made in the last several decades in understanding the structure, dynamics, and transport of the proton and hydroxide ions in different aqueous environments, ranging from water clusters to the bulk liquid and its interfaces with hydrophobic surfaces. The propensity of these ions to accumulate at hydrophobic surfaces has been a subject of intense debate, and we highlight the open issues and challenges in this area. Biological applications reviewed include proton transport along the hydration layer of various membranes and through channel proteins, problems that are at the core of cellular bioenergetics.

  2. Lithium hydroxide, LiOH, at elevated densities

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hermann, Andreas; Ashcroft, N. W.; Hoffmann, Roald

    2014-07-14

    We discuss the high-pressure phases of crystalline lithium hydroxide, LiOH. Using first-principles calculations, and assisted by evolutionary structure searches, we reproduce the experimentally known phase transition under pressure, but we suggest that the high-pressure phase LiOH-III be assigned to a new hydrogen-bonded tetragonal structure type that is unique amongst alkali hydroxides. LiOH is at the intersection of both ionic and hydrogen bonding, and we examine the various ensuing structural features and their energetic driving mechanisms. At P = 17 GPa, we predict another phase transition to a new phase, Pbcm-LiOH-IV, which we find to be stable over a wide pressuremore » range. Eventually, at extremely high pressures of 1100 GPa, the ground state of LiOH is predicted to become a polymeric structure with an unusual graphitic oxygen-hydrogen net. However, because of its ionic character, the anticipated metallization of LiOH is much delayed; in fact, its electronic band gap increases monotonically into the TPa pressure range.« less

  3. Benchmarking polarizable molecular dynamics simulations of aqueous sodium hydroxide by diffraction measurements.

    PubMed

    Vácha, Robert; Megyes, Tunde; Bakó, Imre; Pusztai, László; Jungwirth, Pavel

    2009-04-23

    Results from molecular dynamics simulations of aqueous hydroxide of varying concentrations have been compared with experimental structural data. First, the polarizable POL3 model was verified against neutron scattering using a reverse Monte Carlo fitting procedure. It was found to be competitive with other simple water models and well suited for combining with hydroxide ions. Second, a set of four polarizable models of OH- were developed by fitting against accurate ab initio calculations for small hydroxide-water clusters. All of these models were found to provide similar results that robustly agree with structural data from X-ray scattering. The present force field thus represents a significant improvement over previously tested nonpolarizable potentials. Although it cannot in principle capture proton hopping and can only approximately describe the charge delocalization within the immediate solvent shell around OH-, it provides structural data that are almost entirely consistent with data obtained from scattering experiments.

  4. Metallorganic chemical vapor deposition and atomic layer deposition approaches for the growth of hafnium-based thin films from dialkylamide precursors for advanced CMOS gate stack applications

    NASA Astrophysics Data System (ADS)

    Consiglio, Steven P.

    To continue the rapid progress of the semiconductor industry as described by Moore's Law, the feasibility of new material systems for front end of the line (FEOL) process technologies needs to be investigated, since the currently employed polysilicon/SiO2-based transistor system is reaching its fundamental scaling limits. Revolutionary breakthroughs in complementary-metal-oxide-semiconductor (CMOS) technology were recently announced by Intel Corporation and International Business Machines Corporation (IBM), with both organizations revealing significant progress in the implementation of hafnium-based high-k dielectrics along with metal gates. This announcement was heralded by Gordon Moore as "...the biggest change in transistor technology since the introduction of polysilicon gate MOS transistors in the late 1960s." Accordingly, the study described herein focuses on the growth of Hf-based dielectrics and Hf-based metal gates using chemical vapor-based deposition methods, specifically metallorganic chemical vapor deposition (MOCVD) and atomic layer deposition (ALD). A family of Hf source complexes that has received much attention recently due to their desirable properties for implementation in wafer scale manufacturing is the Hf dialkylamide precursors. These precursors are room temperature liquids and possess sufficient volatility and desirable decomposition characteristics for both MOCVD and ALD processing. Another benefit of using these sources is the existence of chemically compatible Si dialkylamide sources as co-precursors for use in Hf silicate growth. The first part of this study investigates properties of MOCVD-deposited HfO2 and HfSixOy using dimethylamido Hf and Si precursor sources using a customized MOCVD reactor. The second part of this study involves a study of wet and dry surface pre-treatments for ALD growth of HfO2 using tetrakis(ethylmethylamido)hafnium in a wafer scale manufacturing environment. The third part of this study is an investigation of

  5. Hydroxide diffuses slower than hydronium in water because its solvated structure inhibits correlated proton transfer

    NASA Astrophysics Data System (ADS)

    Chen, Mohan; Zheng, Lixin; Santra, Biswajit; Ko, Hsin-Yu; DiStasio, Robert A., Jr.; Klein, Michael L.; Car, Roberto; Wu, Xifan

    2018-03-01

    Proton transfer via hydronium and hydroxide ions in water is ubiquitous. It underlies acid-base chemistry, certain enzyme reactions, and even infection by the flu. Despite two centuries of investigation, the mechanism underlying why hydroxide diffuses slower than hydronium in water is still not well understood. Herein, we employ state-of-the-art density-functional-theory-based molecular dynamics—with corrections for non-local van der Waals interactions, and self-interaction in the electronic ground state—to model water and hydrated water ions. At this level of theory, we show that structural diffusion of hydronium preserves the previously recognized concerted behaviour. However, by contrast, proton transfer via hydroxide is less temporally correlated, due to a stabilized hypercoordination solvation structure that discourages proton transfer. Specifically, the latter exhibits non-planar geometry, which agrees with neutron-scattering results. Asymmetry in the temporal correlation of proton transfer leads to hydroxide diffusing slower than hydronium.

  6. Conduction Channel Formation and Dissolution Due to Oxygen Thermophoresis/Diffusion in Hafnium Oxide Memristors

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kumar, Suhas; Wang, Ziwen; Huang, Xiaopeng

    Due to the favorable operating power, endurance, speed, and density., transition-metal-oxide memristors, or resistive random-access memory (RRAM) switches, are under intense development for storage-class memory. Their commercial deployment critically depends on predictive compact models based on understanding nanoscale physiocochemical forces, which remains elusive and controversial owing to the difficulties in directly observing atomic motions during resistive switching, Here, using scanning transmission synchrotron X-ray spectromicroscopy to study in situ switching of hafnium oxide memristors, we directly observed the formation of a localized oxygen-deficiency-derived conductive channel surrounded by a low-conductivity ring of excess oxygen. Subsequent thermal annealing homogenized the segregated oxygen, resettingmore » the cells toward their as-grown resistance state. We show that the formation and dissolution of the conduction channel are successfully modeled by radial thermophoresis and Fick diffusion of oxygen atoms driven by Joule heating. This confirmation and quantification of two opposing nanoscale radial forces that affect bipolar memristor switching are important components for any future physics-based compact model for the electronic switching of these devices.« less

  7. Low-crystalline iron oxide hydroxide nanoparticle anode for high-performance supercapacitors

    PubMed Central

    Owusu, Kwadwo Asare; Qu, Longbing; Li, Jiantao; Wang, Zhaoyang; Zhao, Kangning; Yang, Chao; Hercule, Kalele Mulonda; Lin, Chao; Shi, Changwei; Wei, Qiulong; Zhou, Liang; Mai, Liqiang

    2017-01-01

    Carbon materials are generally preferred as anodes in supercapacitors; however, their low capacitance limits the attained energy density of supercapacitor devices with aqueous electrolytes. Here, we report a low-crystalline iron oxide hydroxide nanoparticle anode with comprehensive electrochemical performance at a wide potential window. The iron oxide hydroxide nanoparticles present capacitances of 1,066 and 716 F g−1 at mass loadings of 1.6 and 9.1 mg cm−2, respectively, a rate capability with 74.6% of capacitance retention at 30 A g−1, and cycling stability retaining 91% of capacitance after 10,000 cycles. The performance is attributed to a dominant capacitive charge-storage mechanism. An aqueous hybrid supercapacitor based on the iron oxide hydroxide anode shows stability during float voltage test for 450 h and an energy density of 104 Wh kg−1 at a power density of 1.27 kW kg−1. A packaged device delivers gravimetric and volumetric energy densities of 33.14 Wh kg−1 and 17.24 Wh l−1, respectively. PMID:28262797

  8. Study on Kinetic Mechanism of Bastnaesite Concentrates Decomposition Using Calcium Hydroxide

    NASA Astrophysics Data System (ADS)

    Cen, Peng; Wu, Wenyuan; Bian, Xue

    2018-06-01

    The thermal decomposition of bastnaesite concentrates using calcium hydroxide was studied. Calcium hydroxide can effectively inhibit the emission of fluorine during roasting by transforming it to calcium fluoride. The decomposition rate increased with increasing reaction temperature and amount of calcium hydroxide. The decomposition kinetics were investigated. The decomposition reaction was determined to be a heterogeneous gas-solid reaction, and it followed an unreacted shrinking core model. By means of the integrated rate equation method, the reaction was proven to be kinetically first order. Different reaction models were fit to the experimental data to determine the reaction control process. The chemical reaction at the phase interface controlled the reaction rate in the temperatures ranging from 673 K to 773 K (400 °C to 500 °C) with an apparent activation energy of 82.044 kJ·mol-1. From 773 K to 973 K (500 °C to 700 °C), diffusion through the solid product's layer became the determining step, with a lower activation energy of 15.841 kJ·mol-1.

  9. LIGNOSULFONATE-MODIFIED CALCIUM HYDROXIDE FOR SULFUR DIOXIDE CONTROL

    EPA Science Inventory

    The article discusses the use of lignosulfonate-modified calcium hydroxide Ca(OH)2 for sulfur dioxide (SO2) control. The limestone injection multistage burner (LIMB) process is currently being developed at the U.S. EPA as a low cost retrofittable technology for controlling oxides...

  10. Highly effective electronic passivation of silicon surfaces by atomic layer deposited hafnium oxide

    NASA Astrophysics Data System (ADS)

    Cui, Jie; Wan, Yimao; Cui, Yanfeng; Chen, Yifeng; Verlinden, Pierre; Cuevas, Andres

    2017-01-01

    This paper investigates the application of hafnium oxide (HfO2) thin films to crystalline silicon (c-Si) solar cells. Excellent passivation of both n- and p-type crystalline silicon surfaces has been achieved by the application of thin HfO2 films prepared by atomic layer deposition. Effective surface recombination velocities as low as 3.3 and 9.9 cm s-1 have been recorded with 15 nm thick films on n- and p-type 1 Ω cm c-Si, respectively. The surface passivation by HfO2 is activated at 350 °C by a forming gas anneal. Capacitance voltage measurement shows an interface state density of 3.6 × 1010 cm-2 eV-1 and a positive charge density of 5 × 1011 cm-2 on annealed p-type 1 Ω cm c-Si. X-ray diffraction unveils a positive correlation between surface recombination and crystallinity of the HfO2 and a dependence of the crystallinity on both annealing temperature and film thickness. In summary, HfO2 is demonstrated to be an excellent candidate for surface passivation of crystalline silicon solar cells.

  11. Microwave-assisted synthesis of metal oxide/hydroxide composite electrodes for high power supercapacitors - A review

    NASA Astrophysics Data System (ADS)

    Faraji, Soheila; Ani, Farid Nasir

    2014-10-01

    Electrochemical capacitors (ECs), also known as pseudocapacitors or supercapacitors (SCs), is receiving great attention for its potential applications in electric and hybrid electric vehicles because of their ability to store energy, alongside with the advantage of delivering the stored energy much more rapidly than batteries, namely power density. To become primary devices for power supply, supercapacitors must be developed further to improve their ability to deliver high energy and power simultaneously. In this concern, a lot of effort is devoted to the investigation of pseudocapacitive transition-metal-based oxides/hydroxides such as ruthenium oxide, manganese oxide, cobalt oxide, nickel oxide, cobalt hydroxide, nickel hydroxide, and mixed metal oxides/hydroxides such as nickel cobaltite and nickel-cobalt oxy-hydroxides. This is mainly due to the fact that they can produce much higher specific capacitances than typical carbon-based electric double-layer capacitors and electronically conducting polymers. This review presents supercapacitor performance data of metal oxide thin film electrodes by microwave-assisted as an inexpensive, quick and versatile technique. Supercapacitors have established the specific capacitance (Cs) principles, therefore, it is likely that metal oxide films will continue to play a major role in supercapacitor technology and are expected to considerably increase the capabilities of these devices in near future.

  12. A COMPARISON OF EXPERIMENTS AND THREE-DIMENSIONAL ANALYSIS TECHNIQUES. PART I. UNPOISONED UNIFORM SLAB CORE WITH A PARTIALLY INSERTED HAFNIUM ROD

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Renzi, N.E.; Roseberry, R.J.

    >The experimental measurements and nuclear analysis of a uniformly loaded, unpoisoned slab core with a partially insented hafnium rod are described. Comparisons of experimental data with calculated results of the UFO code and flux synthesis techniques are given. It was concluded that one of the flux synthesis techniques and the UFO code are able to predict flux distributions to within approximately 5% of experiment for most cases. An error of approximately 10% was found in the synthesis technique for a channel near the partially inserted rod. The various calculations were able to predict neutron pulsed shutdowns to only approximately 30%.more » (auth)« less

  13. High-energy X-ray detection by hafnium-doped organic-inorganic hybrid scintillators prepared by sol-gel method

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sun, Yan; Koshimizu, Masanori, E-mail: koshi@qpc.che.tohoku.ac.jp; Yahaba, Natsuna

    2014-04-28

    With the aim of enhancing the efficiency with which plastic scintillators detect high-energy X-rays, hafnium-doped organic-inorganic hybrid scintillators were fabricated via a sol-gel method. Transmission electron microscopy of sampled material reveals the presence of Hf{sub x}Si{sub 1−x}O{sub 2} nanoparticles, dispersed in a polymer matrix that constitutes the active material of the X-ray detector. With Hf{sub x}Si{sub 1−x}O{sub 2} nanoparticles incorporated in the polymer matrix, the absorption edge and the luminescence wavelength is shifted, which we attribute to Mie scattering. The detection efficiency for 67.4-keV X-rays in a 0.6-mm-thick piece of this material is two times better than the same thicknessmore » of a commercial plastic scintillator-NE142.« less

  14. Microbial susceptibility to calcium hydroxide pastes and their vehicles.

    PubMed

    Gomes, Brenda Paula Figueiredo de Almeida; Ferraz, Caio Cezar Randi; Garrido, Fabio Devora; Rosalen, Pedro Luiz; Zaia, Alexandre Augusto; Teixeira, Fabricio Batista; de Souza-Filho, Francisco José

    2002-11-01

    The aim of this study was to investigate the susceptibility of some microorganisms commonly isolated from root canals to calcium hydroxide in combination with several vehicles by the agar diffusion method. Stainless-steel cylinders were placed on each inoculated agar medium. The test medications and their controls were placed inside the cylinders. The zones of growth inhibition were measured and recorded after the incubation period for each plate, and the results were analyzed statistically. Enterococcus faecalis was most resistant, whereas the anaerobic Porphyromonas endodontalis was more susceptible to all medications, followed by P. gingivalis and Prevotella intermedial intermedia. Ca(OH)2 + CMCP + glycerin showed significantly larger mean zones of inhibition when compared with the other medications. We conclude that anaerobic Gram-negative bacteria are more susceptible to calcium hydroxide pastes than facultative Gram-positive microorganisms.

  15. An unsupported metal hydroxide for the design of molecular μ-oxo bridged heterobimetallic complexes.

    PubMed

    Falzone, A J; Nguyen, J; Weare, W W; Sommer, R D; Boyle, P D

    2014-02-28

    A terminal and unsupported chromium(III) hydroxide is reported. The terminal hydroxide is used to synthesize the first example of a heterobimetallic Ti-O-Cr compound containing an unsupported μ-oxo bridge. The heterobimetallic complex exhibits a new absorbance at 288 nm (4.32 eV), which is assigned to a metal-to-metal charge transfer (MMCT) transition.

  16. Catalytic and inhibiting effects of lithium peroxide and hydroxide on sodium chlorate decomposition

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cannon, J.C.; Zhang, Y.

    1995-09-01

    Chemical oxygen generators based on sodium chlorate and lithium perchlorate are used in airplanes, submarines, diving, and mine rescue. Catalytic decomposition of sodium chlorate in the presence of cobalt oxide, lithium peroxide, and lithium hydroxide is studied using thermal gravimetric analysis. Lithium peroxide and hydroxide are both moderately active catalysts for the decomposition of sodium chlorate when used alone, and inhibitors when used with the more active catalyst cobalt oxide.

  17. Density-functional tight-binding investigation of the structure, stability and material properties of nickel hydroxide nanotubes

    NASA Astrophysics Data System (ADS)

    Jahangiri, Soran; Mosey, Nicholas J.

    2018-01-01

    Nickel hydroxide is a material composed of two-dimensional layers that can be rolled up to form cylindrical nanotubes belonging to a class of inorganic metal hydroxide nanotubes that are candidates for applications in catalysis, energy storage, and microelectronics. The stabilities and other properties of this class of inorganic nanotubes have not yet been investigated in detail. The present study uses self-consistent-charge density-functional tight-binding calculations to examine the stabilities, mechanical properties, and electronic properties of nickel hydroxide nanotubes along with the energetics associated with the adsorption of water by these systems. The tight-binding model was parametrized for this system based on the results of first-principles calculations. The stabilities of the nanotubes were examined by calculating strain energies and performing molecular dynamics simulations. The results indicate that single-walled nickel hydroxide nanotubes are stable at room temperature, which is consistent with experimental investigations. The nanotubes possess size-dependent mechanical properties that are similar in magnitude to those of other inorganic nanotubes. The electronic properties of the nanotubes were also found to be size-dependent and small nickel oxyhydroxide nanotubes are predicted to be semiconductors. Despite this size-dependence, both the mechanical and electronic properties were found to be almost independent of the helical structure of the nanotubes. The calculations also show that water molecules have higher adsorption energies when binding to the interior of the nickel hydroxide nanotubes when compared to adsorption in nanotubes formed from other two-dimensional materials such as graphene. The increased adsorption energy is due to the hydrophilic nature of nickel hydroxide. Due to the broad applications of nickel hydroxide, the nanotubes investigated here are also expected to be used in catalysis, electronics, and clean energy production.

  18. Biodiesel synthesis using calcined layered double hydroxide catalysts

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Schumaker, J. Link; Crofcheck, Czarena; TAckett, S. Adam

    2008-01-01

    The catalytic properties of calcined Li-Al, Mg-Al and Mg-Fe layered double hydroxides (LDHs) were examined in two transesterification reactions, namely, the reaction of glyceryl tributyrate with methanol, and the reaction of soybean oil with methanol. While the Li-Al catalysts showed high activity in these reactions at the reflux temperature of methanol, the Mg-Fe and Mg-Al catalysts exhibited much lower methyl ester yields. CO2 TPD measurements revealed the presence of sites of weak, medium and strong basicity on both Mg-Al and Li-Al catalysts, the latter showing higher concentrations of medium and strong base sites; by implication, these are the main sitesmore » active in transesterification catalyzed by calcined Li-Al LDHs. Maximum activity was observed for the Li-Al catalysts when a calcination temperature of 450-500 aC was applied, corresponding to decomposition of the layered double hydroxide to the mixed oxide without formation of crystalline lithium aluminate phases.« less

  19. Experimental and Theoretical Studies of Volatile Metal Hydroxides

    NASA Technical Reports Server (NTRS)

    Myers, Dwight L.; Jacobson, Nathan S.

    2015-01-01

    Modern superalloys used in the construction of turbomachinery contain a wide range of metals in trace quantities. In addition, metal oxides and silicon dioxide are used to form Thermal Barrier Coatings (TBC) to protect the underlying metal in turbine blades. Formation of volatile hydroxides at elevated temperatures is an important mechanism for corrosion of metal alloys or oxides in combustion environments (N. Jacobson, D. Myers, E. Opila, and E. Copland, J. Phys. Chem. Solids 66, 471-478, 2005). Thermodynamic data is essential to proper design of components of modern gas turbines. It is necessary to first establish the identity of volatile hydroxides formed from the reaction of a given system with high temperature water vapor, and then to determine the equilibrium pressures of the species under operating conditions. Theoretical calculations of reaction energies are an important check of experimental results. This presentation reports results for several important systems: Si-O-H, Cr-O-H, Al-O-H, Ti-O-H, and ongoing studies of Ta-O-H.

  20. Electrocatalysis and electroanalysis of nickel, its oxides, hydroxides and oxyhydroxides toward small molecules.

    PubMed

    Miao, Yuqing; Ouyang, Lei; Zhou, Shilin; Xu, Lina; Yang, Zhuoyuan; Xiao, Mingshu; Ouyang, Ruizhuo

    2014-03-15

    The electrocatalysis toward small molecules, especially small organic compounds, is of importance in a variety of areas. Nickel based materials such as nickel, its oxides, hydroxides as well as oxyhydroxides exhibit excellent electrocatalysis performances toward many small molecules, which are widely used for fuel cells, energy storage, organic synthesis, wastewater treatment, and electrochemical sensors for pharmaceutical, medical, food or environmental analysis. Their electrocatalytic mechanisms are proposed from three aspects such as Ni(OH)2/NiOOH mediated electrolysis, direct electrocatalysis of Ni(OH)2 or NiOOH. Under exposure to air or aqueous solution, two distinct layers form on the Ni surface with a Ni hydroxide layer at the air-oxide interface and an oxide layer between the metal substrate and the outer hydroxide layer. The transformation from nickel or its oxides to hydroxides or oxyhydroxides could be further speeded up in the strong alkaline solution under the cyclic scanning at relatively high positive potential. The redox transition between Ni(OH)2 and NiOOH is also contributed to the electrocatalytic oxidation of Ni and its oxides toward small molecules in alkaline media. In addition, nickel based materials or nanomaterials, their preparations and applications are also overviewed here. © 2013 Elsevier B.V. All rights reserved.

  1. Aluminum hydroxide, calcium carbonate and calcium acetate in chronic intermittent hemodialysis patients.

    PubMed

    Janssen, M J; van der Kuy, A; ter Wee, P M; van Boven, W P

    1996-02-01

    Prevention of secondary hyperparathyroidism in uremia necessitates correction of hyperphosphatemia and hypocalcemia. In order to avoid aluminum toxicity, calcium containing phosphate binders are used increasingly, instead of aluminium hydroxide. Recent studies have shown that calcium acetate has many characteristics of an ideal phosphate binder. It is, for instance, a more readily soluble salt compared with calcium carbonate. This advantage might, however, disappear if calcium carbonate is taken on an empty stomach, a few minutes before meals. We examined the efficacy of three different phosphate binding agents in a randomized prospective study of 53 patients on regular hemodialysis. Bicarbonate dialyses were performed with a dialysate calcium concentration of 1.75 mmol/l. After a three-week wash-out period, patients received either aluminum hydroxide (control group), calcium acetate, or calcium carbonate as their phosphate binder. Patients were instructed to take the calcium salts a few minutes before meals on an empty stomach, and aluminum hydroxide during meals. Serum calcium, phosphate, intact parathormone, and alkaline phosphatase levels were determined every month. Patient compliance was estimated every month by asking the patients which phosphate binder and what daily dose they had used. Aluminum hydroxide tended to be the most effective phosphate binder. The mean +/- SEM required daily dose of calcium acetate at 12 months was 5.04 +/- 0.60 g, corresponding to 10.1 +/- 1.20 tablets of 500 mg. Co-medication with aluminum hydroxide, however, was needed (1.29 +/- 0.54 g per day, corresponding to 2.6 +/- 1.08 tablets of 500 mg). The required daily calcium carbonate dose appeared to be 2.71 +/- 0.48 g, corresponding to 5.4 +/- 0.95 capsules of 500 mg, with an adjuvant daily aluminum hydroxide dose of 0.69 +/- 0.27 g, corresponding to 1.4 +/- 0.55 tablets of 500 mg (p = 0.0055). Thus, the mean daily doses of elemental calcium were comparable between the calcium

  2. Antibiofilm efficacy of silver nanoparticles as a vehicle for calcium hydroxide medicament against Enterococcus faecalis.

    PubMed

    Afkhami, Farzaneh; Pourhashemi, Seyyed Jalal; Sadegh, Mona; Salehi, Yasaman; Fard, Mohammad Javad Kharrazi

    2015-12-01

    The aim of the present study was to investigate antibacterial characteristic and Enterococcus faecalis (E. faecalis) biofilm suppression effect of different vehicles of calcium hydroxide as intracanal medicaments in short and long-term. Fifty-four human single-root teeth were contaminated with E. faecalis bacteria. The teeth were randomly divided into three experimental (n=16) and one control group (n=6). Each group was then exposed to various intracanal medicaments, namely calcium hydroxide paste (group 1), calcium hydroxide with chlorhexidine (group 2), calcium hydroxide with silver nanoparticles suspension (AgNPs) (group 3), and saline as the control group (group 4). Cultures were made from each group after one week and one month, and the number of colonies was counted. Moreover, a sample of each group was examined under electron microscope. Kruskal-Wallis test served for inter-group comparisons, and Mann-Whitney test served for comparison between the two incubation periods. All the intracanal medicaments resulted in significant decrease in number of colonies compared to control group in both incubation periods. After one week, the mixture of calcium hydroxide and AgNPs was the most effective medicament against E. faecalis bacteria (p<.05). No significant difference in antibacterial effect of the medicaments existed after one month incubation period (p>.05). AgNPs was more effective on the E. faecalis biofilm than other tested vehicles in short-term medication. AgNPs seems to have a good potential to be used as an appropriate vehicle of calcium hydroxide in order to eliminate of E. faecalis biofilm from human dentine in short-term. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Bubble nucleation and migration in a lead–iron hydr(oxide) core–shell nanoparticle

    PubMed Central

    Niu, Kaiyang; Frolov, Timofey; Xin, Huolin L.; Wang, Junling; Asta, Mark; Zheng, Haimei

    2015-01-01

    Iron hydroxide is found in a wide range of contexts ranging from biominerals to steel corrosion, and it can transform to anhydrous oxide via releasing O2 gas and H2O. However, it is not well understood how gases transport through a crystal lattice. Here, we present in situ observation of the nucleation and migration of gas bubbles in iron (hydr)oxide using transmission electron microscopy. We create Pb–FeOOH model core–shell nanoparticles in a liquid cell. Under electron irradiation, iron hydroxide transforms to iron oxide, during which bubbles are generated, and they migrate through the shell to the nanoparticle surface. Geometric phase analysis of the shell lattice shows an inhomogeneous stain field at the bubbles. Our modeling suggests that the elastic interaction between the core and the bubble provides a driving force for bubble migration. PMID:26438864

  4. 21 CFR 73.1010 - Alumina (dried aluminum hydroxide).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Alumina (dried aluminum hydroxide). 73.1010 Section 73.1010 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1010 Alumina (dried aluminum...

  5. 21 CFR 73.1010 - Alumina (dried aluminum hydroxide).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Alumina (dried aluminum hydroxide). 73.1010 Section 73.1010 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1010 Alumina (dried aluminum...

  6. 21 CFR 73.1010 - Alumina (dried aluminum hydroxide).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Alumina (dried aluminum hydroxide). 73.1010 Section 73.1010 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1010 Alumina (dried aluminum...

  7. 75 FR 28608 - Calcium Hydroxide; Receipt of Application for Emergency Exemption, Solicitation of Public Comment

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-21

    ... ENVIRONMENTAL PROTECTION AGENCY [EPA-HQ-OPP-2010-0411; FRL-8826-7] Calcium Hydroxide; Receipt of... Department of Agriculture to use the pesticide calcium hydroxide (CAS No. 1305-62-0) to treat up to 1,000...: [email protected] . SUPPLEMENTARY INFORMATION: I. General Information A. Does this Action Apply to Me...

  8. Respiration of metal (hydr)oxides by Shewanella and Geobacter: a key role for multihaem c-type cytochromes

    PubMed Central

    Shi, Liang; Squier, Thomas C; Zachara, John M; Fredrickson, James K

    2007-01-01

    Dissimilatory reduction of metal (e.g. Fe, Mn) (hydr)oxides represents a challenge for microorganisms, as their cell envelopes are impermeable to metal (hydr)oxides that are poorly soluble in water. To overcome this physical barrier, the Gram-negative bacteria Shewanella oneidensis MR-1 and Geobacter sulfurreducens have developed electron transfer (ET) strategies that require multihaem c-type cytochromes (c-Cyts). In S. oneidensis MR-1, multihaem c-Cyts CymA and MtrA are believed to transfer electrons from the inner membrane quinone/quinol pool through the periplasm to the outer membrane. The type II secretion system of S. oneidensis MR-1 has been implicated in the reduction of metal (hydr)oxides, most likely by translocating decahaem c-Cyts MtrC and OmcA across outer membrane to the surface of bacterial cells where they form a protein complex. The extracellular MtrC and OmcA can directly reduce solid metal (hydr)oxides. Likewise, outer membrane multihaem c-Cyts OmcE and OmcS of G. sulfurreducens are suggested to transfer electrons from outer membrane to type IV pili that are hypothesized to relay the electrons to solid metal (hydr)oxides. Thus, multihaem c-Cyts play critical roles in S. oneidensis MR-1- and G. sulfurreducens-mediated dissimilatory reduction of solid metal (hydr)oxides by facilitating ET across the bacterial cell envelope. PMID:17581116

  9. 40 CFR 721.6183 - Amides, from ammonium hydroxide - maleic anhydride polymer and hydrogenated tallow alkyl amines...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Amides, from ammonium hydroxide - maleic anhydride polymer and hydrogenated tallow alkyl amines, sodium salts, compds. with ethanolamine... Substances § 721.6183 Amides, from ammonium hydroxide - maleic anhydride polymer and hydrogenated tallow...

  10. 40 CFR 721.6183 - Amides, from ammonium hydroxide - maleic anhydride polymer and hydrogenated tallow alkyl amines...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Amides, from ammonium hydroxide - maleic anhydride polymer and hydrogenated tallow alkyl amines, sodium salts, compds. with ethanolamine... Substances § 721.6183 Amides, from ammonium hydroxide - maleic anhydride polymer and hydrogenated tallow...

  11. 40 CFR 721.6183 - Amides, from ammonium hydroxide - maleic anhydride polymer and hydrogenated tallow alkyl amines...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Amides, from ammonium hydroxide - maleic anhydride polymer and hydrogenated tallow alkyl amines, sodium salts, compds. with ethanolamine... Substances § 721.6183 Amides, from ammonium hydroxide - maleic anhydride polymer and hydrogenated tallow...

  12. Associating cooking additives with sodium hydroxide to pretreat bamboo residues for improving the enzymatic saccharification and monosaccharides production.

    PubMed

    Huang, Caoxing; He, Juan; Wang, Yan; Min, Douyong; Yong, Qiang

    2015-10-01

    Cooking additive pulping technique is used in kraft mill to increase delignification degree and pulp yield. In this work, cooking additives were firstly applied in the sodium hydroxide pretreatment for improving the bioconversion of bamboo residues to monosaccharides. Meanwhile, steam explosion and sulfuric acid pretreatments were also carried out on the sample to compare their impacts on monosaccharides production. Results indicated that associating anthraquinone with sodium hydroxide pretreatment showed the best performance in improving the original carbohydrates recovery, delignification, enzymatic saccharification, and monosaccharides production. After consecutive pretreatment and enzymatic saccharification process, 347.49 g, 307.48 g, 142.93 g, and 87.15 g of monosaccharides were released from 1000 g dry bamboo residues pretreated by sodium hydroxide associating with anthraquinone, sodium hydroxide, steam explosion and sulfuric acid, respectively. The results suggested that associating cooking additive with sodium hydroxide is an effective pretreatment for bamboo residues to enhance enzymatic saccharification for monosaccharides production. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Synthesis of neodymium hydroxide nanotubes and nanorods by soft chemical process.

    PubMed

    Shi, Weidong; Yu, Jiangbo; Wang, Haishui; Yang, Jianhui; Zhang, Hongjie

    2006-08-01

    A facile soft chemical approach using cetyltrimethylammonium bromide (CTAB) as template is successfully designed for synthesis of neodymium hydroxide nanotubes. These nanotubes have an average outer diameter around 20 nm, inner diameter around 2 nm, and length ranging from 100 to 120 nm, high BET surface area of 495.71 m(2) g(-1). We also find that neodymium hydroxide nanorods would be obtained when CTAB absented in reaction system. The Nd(OH)3 nanorods might act as precursors that are converted into Nd2O3 nanorods through dehydration at 550 degrees C. The nanorods could exhibit upconversion emission characteristic under excitation of 591 nm at room temperature.

  14. Bubble nucleation and migration in a lead-iron hydr(oxide) core-shell nanoparticle

    DOE PAGES

    Niu, Kaiyang; Frolov, Timofey; Xin, Huolin L.; ...

    2015-10-05

    Iron hydroxide is found in a wide range of contexts ranging from biominerals to steel corrosion, and it can transform to anhydrous oxide via releasing O 2 gas and H 2O. However, it is not well understood how gases transport through a crystal lattice. Here, we present in situ observation of the nucleation and migration of gas bubbles in iron (hydr)oxide using transmission electron microscopy. We create Pb–FeOOH model core–shell nanoparticles in a liquid cell. Under electron irradiation, iron hydroxide transforms to iron oxide, during which bubbles are generated, and they migrate through the shell to the nanoparticle surface. Geometricmore » phase analysis of the shell lattice shows an inhomogeneous stain field at the bubbles. In conclusion, our modeling suggests that the elastic interaction between the core and the bubble provides a driving force for bubble migration.« less

  15. Reactive transport modeling at uranium in situ recovery sites: uncertainties in uranium sorption on iron hydroxides

    USGS Publications Warehouse

    Johnson, Raymond H.; Tutu, Hlanganani; Brown, Adrian; Figueroa, Linda; Wolkersdorfer, Christian

    2013-01-01

    Geochemical changes that can occur down gradient from uranium in situ recovery (ISR) sites are important for various stakeholders to understand when evaluating potential effects on surrounding groundwater quality. If down gradient solid-phase material consists of sandstone with iron hydroxide coatings (no pyrite or organic carbon), sorption of uranium on iron hydroxides can control uranium mobility. Using one-dimensional reactive transport models with PHREEQC, two different geochemical databases, and various geochemical parameters, the uncertainties in uranium sorption on iron hydroxides are evaluated, because these oxidized zones create a greater risk for future uranium transport than fully reduced zones where uranium generally precipitates.

  16. Ionic Strength-Controlled Mn (Hydr)oxide Nanoparticle Nucleation on Quartz: Effect of Aqueous Mn(OH)2.

    PubMed

    Jung, Haesung; Jun, Young-Shin

    2016-01-05

    The early formation of manganese (hydr)oxide nanoparticles at mineral-water interfaces is crucial in understanding how Mn oxides control the fate and transport of heavy metals and the cycling of nutrients. Using atomic force microscopy, we investigated the heterogeneous nucleation and growth of Mn (hydr)oxide under varied ionic strengths (IS; 1-100 mM NaNO3). Experimental conditions (i.e., 0.1 mM Mn(2+) (aq) concentration and pH 10.1) were chosen to be relevant to Mn remediation sites. We found that IS controls Mn(OH)2 (aq) formation, and that the controlled Mn(OH)2 (aq) formation can affect the system's saturation and subsequent Mn(OH)2 (s) and further Mn3O4 (s) nanoparticle formation. In 100 mM IS system, nucleated Mn (hydr)oxide particles had more coverage on the quartz substrate than those in 1 mM and 10 mM IS systems. This high IS also resulted in low supersaturation ratio and thus favor heterogeneous nucleation, having better structural matching between nucleating Mn (hydr)oxides and quartz. The unique information obtained in this work improves our understanding of Mn (hydr)oxide formation in natural as well as engineered aqueous environments, such as groundwater contaminated by natural leachate and acid mine drainage remediation.

  17. 40 CFR 721.10018 - Calcium hydroxide oxide silicate (Ca6(OH)2O2(Si2O5)3).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Calcium hydroxide oxide silicate (Ca6... New Uses for Specific Chemical Substances § 721.10018 Calcium hydroxide oxide silicate (Ca6(OH)2O2... substance identified as calcium hydroxide oxide silicate (Ca6(OH)2O2(Si2O5)3) (PMN P-01-442; CAS No. 13169...

  18. 40 CFR 721.10018 - Calcium hydroxide oxide silicate (Ca6(OH)2O2(Si2O5)3).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Calcium hydroxide oxide silicate (Ca6... New Uses for Specific Chemical Substances § 721.10018 Calcium hydroxide oxide silicate (Ca6(OH)2O2... substance identified as calcium hydroxide oxide silicate (Ca6(OH)2O2(Si2O5)3) (PMN P-01-442; CAS No. 13169...

  19. 40 CFR 721.10018 - Calcium hydroxide oxide silicate (Ca6(OH)2O2(Si2O5)3).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Calcium hydroxide oxide silicate (Ca6... New Uses for Specific Chemical Substances § 721.10018 Calcium hydroxide oxide silicate (Ca6(OH)2O2... substance identified as calcium hydroxide oxide silicate (Ca6(OH)2O2(Si2O5)3) (PMN P-01-442; CAS No. 13169...

  20. 40 CFR 721.10018 - Calcium hydroxide oxide silicate (Ca6(OH)2O2(Si2O5)3).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Calcium hydroxide oxide silicate (Ca6... New Uses for Specific Chemical Substances § 721.10018 Calcium hydroxide oxide silicate (Ca6(OH)2O2... substance identified as calcium hydroxide oxide silicate (Ca6(OH)2O2(Si2O5)3) (PMN P-01-442; CAS No. 13169...

  1. 40 CFR 721.10018 - Calcium hydroxide oxide silicate (Ca6(OH)2O2(Si2O5)3).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Calcium hydroxide oxide silicate (Ca6... New Uses for Specific Chemical Substances § 721.10018 Calcium hydroxide oxide silicate (Ca6(OH)2O2... substance identified as calcium hydroxide oxide silicate (Ca6(OH)2O2(Si2O5)3) (PMN P-01-442; CAS No. 13169...

  2. Ultrathin platinum nanowires grown on single-layered nickel hydroxide with high hydrogen evolution activity.

    PubMed

    Yin, Huajie; Zhao, Shenlong; Zhao, Kun; Muqsit, Abdul; Tang, Hongjie; Chang, Lin; Zhao, Huijun; Gao, Yan; Tang, Zhiyong

    2015-03-02

    Design and synthesis of effective electrocatalysts for hydrogen evolution reaction in alkaline environments is critical to reduce energy losses in alkaline water electrolysis. Here we report a hybrid nanomaterial comprising of one-dimensional ultrathin platinum nanowires grown on two-dimensional single-layered nickel hydroxide. Judicious surface chemistry to generate the fully exfoliated nickel hydroxide single layers is explored to be the key for controllable growth of ultrathin platinum nanowires with diameters of about 1.8 nm. Impressively, this hybrid nanomaterial exhibits superior electrocatalytic activity for hydrogen evolution reaction in alkaline solution, which outperforms currently reported catalysts, and the obviously improved catalytic stability. We believe that this work may lead towards the development of single-layered metal hydroxide-based hybrid materials for applications in catalysis and energy conversion.

  3. Evaluation of calcium ion, hydroxyl ion release and pH levels in various calcium hydroxide based intracanal medicaments: An in vitro study

    PubMed Central

    Fulzele, Punit; Baliga, Sudhindra; Thosar, Nilima; Pradhan, Debaprya

    2011-01-01

    Aims: Evaluation of calcium ion and hydroxyl ion release and pH levels in various calcium hydroxide based intracanal medicaments. Objective: The purpose of this study was to evaluate calcium and hydroxyl ion release and pH levels of calcium hydroxide based products, namely, RC Cal, Metapex, calcium hydroxide with distilled water, along with the new gutta-percha points with calcium hydroxide. Materials and Methods: The materials were inserted in polyethylene tubes and immersed in deionized water. The pH variation, Ca++ and OH- release were monitored periodically for 1 week. Statistical Analysis Used: Statistical analysis was carried out using one-way analysis of variance and Tukey's post hoc tests with PASW Statistics version 18 software to compare the statistical difference. Results: After 1 week, calcium hydroxide with distilled water and RC Cal raised the pH to 12.7 and 11.8, respectively, while a small change was observed for Metapex, calcium hydroxide gutta-percha points. The calcium released after 1 week was 15.36 mg/dL from RC Cal, followed by 13.04, 1.296, 3.064 mg/dL from calcium hydroxide with sterile water, Metapex and calcium hydroxide gutta-percha points, respectively. Conclusions: Calcium hydroxide with sterile water and RC Cal pastes liberate significantly more calcium and hydroxyl ions and raise the pH higher than Metapex and calcium hydroxidegutta-percha points. PMID:22346155

  4. Microbial mediated iron redox cycling in Fe (hydr)oxides for nitrite removal.

    PubMed

    Lu, Yongsheng; Xu, Lu; Shu, Weikang; Zhou, Jizhi; Chen, Xueping; Xu, Yunfeng; Qian, Guangren

    2017-01-01

    Nitrite, at an environmentally relevant concentration, was significantly reduced with iron (hydr)oxides mediated by Shewanella oneidensis MR-1. The average nitrite removal rates of 1.28±0.08 and 0.65±0.02(mgL -1 )h -1 were achieved with ferrihydrite and magnetite, respectively. The results showed that nitrite removal was able to undergo multiple redox cycles with iron (hydr)oxides mediated by Shewanella oneidensis MR-1. During the bioreduction of the following cycles, biogenic Fe(II) was subsequently chemically oxidized to Fe(III), which is associated with nitrite reduction. There was 11.18±1.26mgL -1 of NH 4 + -N generated in the process of redox cycling of ferrihydrite. Additionally, results obtained by using X-ray diffraction showed that ferrihydrite and magnetite remained mainly stable in the system. This study indicated that redox cycling of Fe in iron (hydr)oxides was a potential process associated with NO 2 - -N removal from solution, and reduced most nitrite abiotically to gaseous nitrogen species. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Forced-convection Heat-transfer Characteristics of Molten Sodium Hydroxide

    NASA Technical Reports Server (NTRS)

    Grele, Milton D; Gedeon, Louis

    1953-01-01

    The forced-convection heat-transfer characteristics of sodium hydroxide were experimentally investigated. The heat-transfer data for heating fall slightly above the McAdams correlation line, and the heat-transfer data for cooling are fairly well represented by the McAdams correlation line.

  6. Magnetically retrievable nickel hydroxide functionalised AFe2O4 (A = Mn, Ni) spinel nanocatalyst for alcohol oxidation

    NASA Astrophysics Data System (ADS)

    Bhat, Pooja B.; Bhat, Badekai Ramachandra

    2016-03-01

    Ultrasmall nickel hydroxide functionalised AFe2O4 (A = Mn, Ni) nanocatalyst was synthesized by traditional co-precipitation method and was examined for oxidation of aromatic alcohols to carbonyls using hydrogen peroxide as terminal oxidant. A very high surface area of 104.55 m2 g-1 was achieved for ferromagnetic MnFe2O4 and 100.50 m2 g-1 for superparamagnetic NiFe2O4, respectively. Efficient oxidation was observed due to the synergized effect of nickel hydroxide (bronsted base) on Lewis center (Fe) of the nanocatalyst. Catalyst recycling experiments revealed that the ultrasmall nanocatalyst can be easily recovered by external magnet and applied for nearly complete oxidation of alcohols for at least five successive cycles. Furthermore, the nickel hydroxide functionalised ultrasmall nanocatalyst exhibited higher efficiency for benzyl alcohol oxidation compared to Ni(OH)2, bare MnFe2O4 and NiFe2O4. Higher conversion rate was observed for nickel hydroxide functionalised NiFe2O4 compared to MnFe2O4. Ultrasmall magnetic nickel hydroxide functionalised nanocatalyst showed environmental friendly, greener route for the oxidation of alcohols without significant loss in activity and selectivity within successive runs.

  7. Provisional Peer-Reviewed Toxicity Values for Rubidium Compounds (Rubidium Hydroxide)

    EPA Science Inventory

    This is a PPRTV for Rubidium Compounds submitted to the Superfund Program.This assessment supports multiple isomers (see related links) and this page is about the chemical rubidium hydroxide, CASRN 1310-82-3.

  8. Measurement and Simulation of Thermal Conductivity of Hafnium-Aluminum Thermal Neutron Absorber Material

    DOE PAGES

    Guillen, Donna Post; Harris, William H.

    2016-05-11

    A metal matrix composite (MMC) material comprised of hafnium aluminide (Al3Hf) intermetallic particles in an aluminum matrix has been identified as a promising material for fast-flux irradiation testing applications. This material can filter thermal neutrons while simultaneously providing high rates of conductive cooling for experiment capsules. Our purpose is to investigate effects of Hf-Al material composition and neutron irradiation on thermophysical properties, which were measured before and after irradiation. When performing differential scanning calorimetry (DSC) on the irradiated specimens, a large exotherm corresponding to material annealment was observed. Thus, a test procedure was developed to perform DSC and laser flashmore » analysis (LFA) to obtain the specific heat and thermal diffusivity of pre- and post-annealment specimens. This paper presents the thermal properties for three states of the MMC material: (1) unirradiated, (2) as-irradiated, and (3) irradiated and annealed. Microstructure-property relationships were obtained for the thermal conductivity. These relationships are useful for designing components from this material to operate in irradiation environments. Furthermore, the ability of this material to effectively conduct heat as a function of temperature, volume fraction Al 3Hf, radiation damage and annealing is assessed using the MOOSE suite of computational tools.« less

  9. Ferroelectric transistors with monolayer molybdenum disulfide and ultra-thin aluminum-doped hafnium oxide

    NASA Astrophysics Data System (ADS)

    Yap, Wui Chung; Jiang, Hao; Liu, Jialun; Xia, Qiangfei; Zhu, Wenjuan

    2017-07-01

    In this letter, we demonstrate ferroelectric memory devices with monolayer molybdenum disulfide (MoS2) as the channel material and aluminum (Al)-doped hafnium oxide (HfO2) as the ferroelectric gate dielectric. Metal-ferroelectric-metal capacitors with 16 nm thick Al-doped HfO2 are fabricated, and a remnant polarization of 3 μC/cm2 under a program/erase voltage of 5 V is observed. The capability of potential 10 years data retention was estimated using extrapolation of the experimental data. Ferroelectric transistors based on embedded ferroelectric HfO2 and MoS2 grown by chemical vapor deposition are fabricated. Clockwise hysteresis is observed at low program/erase voltages due to slow bulk traps located near the 2D/dielectric interface, while counterclockwise hysteresis is observed at high program/erase voltages due to ferroelectric polarization. In addition, the endurances of the devices are tested, and the effects associated with ferroelectric materials, such as the wake-up effect and polarization fatigue, are observed. Reliable writing/reading in MoS2/Al-doped HfO2 ferroelectric transistors over 2 × 104 cycles is achieved. This research can potentially lead to advances of two-dimensional (2D) materials in low-power logic and memory applications.

  10. 68. INTERIOR VIEW LOOKING OF THE CAUSTIC SODA (SODIUM HYDROXIDE) ...

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

    68. INTERIOR VIEW LOOKING OF THE CAUSTIC SODA (SODIUM HYDROXIDE) BUILDING, LOOKING AT CAUSTIC SODA MEASURING TANKS. (DATE UNKNOWN). - United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Muscle Shoals, Colbert County, AL

  11. Layered gadolinium hydroxides for low-temperature magnetic cooling.

    PubMed

    Abellán, Gonzalo; Espallargas, Guillermo Mínguez; Lorusso, Giulia; Evangelisti, Marco; Coronado, Eugenio

    2015-09-28

    Layered gadolinium hydroxides have revealed to be excellent candidates for cryogenic magnetic refrigeration. These materials behave as pure 2D magnetic systems with a Heisenberg-Ising critical crossover, induced by dipolar interactions. This 2D character and the possibility offered by these materials to be delaminated open the possibility of rapid heat dissipation upon substrate deposition.

  12. Application of nanodimensional particles and aluminum hydroxide nanostructures for cancer diagnosis and therapy

    NASA Astrophysics Data System (ADS)

    Korovin, M. S.; Fomenko, A. N.

    2017-09-01

    Nanoparticles and nanostructured materials are one of the most promising developments for cancer therapy. Gold nanoparticles, magnetic nanoparticles based on iron and its oxides and other metal oxides have been widely used in diagnosis and treatment of cancer. Much less researchers' attention has been paid to nanoparticles and nanostructures based on aluminum oxides and hydroxides as materials for cancer diagnosis and treatment. However, recent investigations have shown promising results regarding these objects. Here, we review the antitumor results obtained with different aluminum oxide/hydroxide nanoparticles and nanostructures.

  13. Ammonia induced precipitation of cobalt hydroxide: observation of turbostratic disorder

    NASA Astrophysics Data System (ADS)

    Ramesh, T. N.; Rajamathi, Michael; Kamath, P. Vishnu

    2003-05-01

    Cobalt hydroxide freshly precipitated from aqueous solutions of Co salts using ammonia, is a layered phase having a 9.17 Å interlayer spacing. DIFFaX simulations of the PXRD pattern reveal that it is turbostratically disordered.

  14. Praseodymium hydroxide and oxide nanorods and Au/Pr6O11 nanorod catalysts for CO oxidation.

    PubMed

    Huang, P X; Wu, F; Zhu, B L; Li, G R; Wang, Y L; Gao, X P; Zhu, H Y; Yan, T Y; Huang, W P; Zhang, S M; Song, D Y

    2006-02-02

    Praseodymium hydroxide nanorods were synthesized by a two-step approach: First, metallic praseodymium was used to form praseodymium chloride, which reacted subsequently with KOH solution to produce praseodymium hydroxide. In the second step the hydroxide was treated with a concentrated alkaline solution at 180 degrees C for 45 h, yielding nanorods as shown by the scanning and transmission electron microscopy images. The results of X-ray diffraction and energy-dispersive X-ray spectroscopy experiments indicate that these nanorods are pure praseodymium hydroxide with a hexagonal structure, which can be converted into praseodymium oxide (Pr6O11) nanorods of a face-centered cubic structure after calcination at 600 degrees C for 2 h in air. Gold was loaded on the praseodymium oxide nanorods using HAuCl4 as the gold source, and NaBH4 was used to reduce the gold species to metallic nanoparticles with sizes of 8-12 nm on the nanorod surface. These Au/Pr6O11 nanorods exhibit superior catalytic activity for CO oxidation.

  15. Evaluation of barium hydroxide treatment efficacy on a dolomitic marble.

    PubMed

    Toniolo, L; Colombo, C; Realini, M; Peraio, A; Positano, M

    2001-01-01

    The Arch of Peace, by Luigi Cagnola, is one of the most famous neoclassical monuments in Milan. It has been subjected to conservative intervention in 1998. In the present paper the efficacy of the consolidation by means of barium hydroxide has been evaluated. The stone material showed severe degradation phenomena as: erosion, pulverisation, exfoliation. The analytical data acquired through X-ray diffraction (XRD), infrared spectrophotometry (FTIR) and scanning electron microscopy (SEM-EDX), allowed to compare the conditions of stone before and after the treatment with barium hydroxide. The presence of barium has been put in evidence mainly on the surface as barium sulphate, whereas barium is only sporadically present within the thickness of the decayed material. The treatment was judged not satisfying and its inefficacy is, most probably, due to a not suitable cleaning procedure carried out before the consolidation.

  16. Negative cerium anomalies in manganese (hydr)oxide precipitates due to cerium oxidation in the presence of dissolved siderophores

    NASA Astrophysics Data System (ADS)

    Kraemer, Dennis; Tepe, Nathalie; Pourret, Olivier; Bau, Michael

    2017-01-01

    We present experimental results on the sorption behavior of rare earth elements and yttrium (REY) on precipitating manganese (hydr)oxide in the presence of the biogenic siderophore desferrioxamine B (DFOB). In marked contrast to inorganic systems, where preferential adsorption of HREY and depletion of LREY is commonly observed in manganese (hydr)oxide precipitates, sorption of REY in presence of the DFOB siderophore leads to HREY-depleted and LREY-enriched patterns in the precipitates. Moreover, our data indicate that surface oxidation of Ce(III) to Ce(IV) during sorption onto manganese (hydr)oxides and the resulting development of a positive Ce anomaly, which are commonly observed in inorganic experiments, are prevented in the presence of DFOB. Instead, Ce(III) is oxidized to Ce(IV) but associated with the dissolved desferrioxamine B which forms complexes with Ce(IV), that are at least twenty orders of magnitude more stable than those with Ce(III) and REY(III). The overall result is the formation of a positive Ce anomaly in the solution and a negative Ce anomaly in the Mn (hydr)oxides. The distribution of the strictly trivalent REY and Eu(III) between the manganese (hydr)oxide phase and the remaining ambient solution mimics the distribution of published stability constants for complexes of REY(III) with DFOB, i.e. the heavy REY form more stable complexes with the ligand and hence are better shielded from sorption than the LREY. Surface complexation modeling corroborates our experimental results. Negative Ce anomalies in Mn precipitates have been described from biogenic Mn oxides. Our results provide experimental evidence for the development of negative Ce anomalies in abiogenic Mn (hydr)oxide precipitates and show that the presence of the widespread siderophore desferrioxamine B during mineral precipitation results in HREY-depleted Mn (hydr)oxides with negative Ce anomalies.

  17. Pretreatment of poly(l-lactide-co-glycolide) scaffolds with sodium hydroxide enhances osteoblastic differentiation and slows proliferation of mouse preosteoblast cells.

    PubMed

    Carpizo, Katherine H; Saran, Madeleine J; Huang, Weibiao; Ishida, Kenji; Roostaeian, Jason; Bischoff, David; Huang, Catherine K; Rudkin, George H; Yamaguchi, Dean T; Miller, Timothy A

    2008-02-01

    Surface topography is important in the creation of a scaffold for tissue engineering. Chemical etching of poly(l-lactide-co-glycolide) with sodium hydroxide has been shown to enhance adhesion and function of numerous cell types. The authors investigated the effects of sodium hydroxide pretreatment of three-dimensional poly(l-lactide-co-glycolide) scaffolds on the adhesion, differentiation, and proliferation of MC3T3-E1 murine preosteoblasts. MC3T3-E1 cells were seeded onto three-dimensional poly(l-lactide-co-glycolide) scaffolds with and without 1 M sodium hydroxide pretreatment. Cells were then cultured in osteogenic medium and harvested at varying time points for RNA extraction. Quantitative real-time reverse-transcriptase polymerase chain reaction was performed to measure mRNA expression of several osteogenic marker genes. In addition, cell numbers were determined at varying time points during the culture period. All experiments were performed in triplicate. Pretreatment of three-dimensional poly(l-lactide-co-glycolide) scaffolds with sodium hydroxide resulted in statistically significant up-regulation of mRNA expression of alkaline phosphatase, bone sialoprotein, osteocalcin, and vascular endothelial growth factor during the first 10 days of culture. Histologic analysis demonstrated a striking increase in mineralized cell matrix deposition in the sodium hydroxide-treated group. Cell number was statistically higher in the sodium hydroxide-treated group immediately after cell seeding, suggesting improved adhesion. During the first 24 hours of culture, cells grew faster in the control group than in the sodium hydroxide-treated group. Chemical etching of poly(l-lactide-co-glycolide) scaffolds with sodium hydroxide strongly influences the behavior of MC3T3-E1 preosteoblasts in vitro by enhancing adhesion and differentiation and slowing proliferation. Sodium hydroxide treatment may represent a simple and inexpensive way of improving scaffolds for use in bone tissue

  18. Effect of the Association of Nonsteroidal Anti-inflammatory and Antibiotic Drugs on Antibiofilm Activity and pH of Calcium Hydroxide Pastes.

    PubMed

    de Freitas, Rafaela Pignatti; Greatti, Vanessa Raquel; Alcalde, Murilo Priori; Cavenago, Bruno Cavalini; Vivan, Rodrigo Ricci; Duarte, Marco Antonio Hungaro; Weckwerth, Ana Carolina Villas Bôas; Weckwerth, Paulo Henrique

    2017-01-01

    The objective of the present study was to evaluate the in vitro antibiofilm activity and pH of calcium hydroxide associated with different nonsteroidal anti-inflammatory drugs (NSAIDs). The groups analyzed were as follows: group 1, calcium hydroxide paste with propylene glycol; group 2, calcium hydroxide paste with propylene glycol + 5% diclofenac sodium; group 3, calcium hydroxide paste with propylene glycol + 5% ibuprofen; group 4, calcium hydroxide paste with propylene glycol + 5% ciprofloxacin; and group 6, positive control (without medication). For analysis of the pH, the pastes were inserted into tubes and immersed in flasks containing ultrapure water. At the time intervals of 3, 24, 72, and 168 hours, the pH was measured with a calibrated pH meter. For microbial analysis, biofilm was induced in 30 bovine dentin blocks for 21 days. Subsequently, the pastes were placed on the blocks with biofilm for 7 days. Afterward, the pastes were removed by irrigation with sterile water, and the specimens were analyzed with a laser scanning confocal microscope with the 50 μL Live/Dead BacLight Bacterial Viability solution L7012 Kit (Molecular Probes, Inc, Eugene, OR). Data were subjected to statistical analysis at a significance level of 5%. The highest pH values were found for calcium hydroxide associated with ciprofloxacin in all periods analyzed. With the exception of pure calcium hydroxide paste, the other groups showed statistically significant differences (P < .05) in comparison with the positive control. The association of NSAIDs or antibiotic did not interfere with the pH of calcium hydroxide paste and increased the antimicrobial action of calcium hydroxide paste against Enterococcus faecalis biofilm formation. Published by Elsevier Inc.

  19. Mechanochemical synthesis of low-fluorine doped aluminum hydroxide fluorides

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Scalise, V.; Scholz, G., E-mail: gudrun.scholz@rz.hu-berlin.de; Kemnitz, E., E-mail: erhard.kemnitz@chemie.hu-berlin.de

    2016-11-15

    Different aluminum hydroxide fluorides with varying Al/F molar ratios from 1:1.5 up to 1:0.05 were successfully synthesized by mechanochemical reactions. The characterization of the products by XRD, {sup 27}Al and {sup 19}F MAS NMR, thermal analysis, nitrogen adsorption and zeta potential techniques allows a detailed understanding of the structure and surface properties of the products. Using γ-Al(OH){sub 3} and β-AlF{sub 3}·3H{sub 2}O as OH- and F-sources, respectively, strongly disordered products were obtained with an Al: F molar ratio higher than 1:0.25. The fluorination degree has affected the amount of 4- and 5-fold coordinated Al sites, not present in the reactants.more » An evolution of the sub-coordinated Al-species has been detected also as a consequence of annealing processes. Obviously, these species affect the phase transition to alumina, by decreasing the transition temperature of the formation of α-Al{sub 2}O{sub 3}. Synthesis conditions (milling time, fluorination degree) play a crucial role for the product composition. - Graphical abstract: The impact of the combined action of the milling and the different fluorine doping on the structure of new aluminum hydroxide fluorides was followed by {sup 27}Al and {sup 19}F NMR and by other complementary techniques. - Highlights: • Low F-doped Al-hydroxide fluorides can be successfully prepared by mechanosynthesis. • Both F-doping and mechanochemical synthesis introduce a high number of defects in the structure. • The fluorination degree affects the amount of 4- and 5-fold coordinated Al sites as well as the transition temperature to corundum.« less

  20. Aqueous alkali metal hydroxide insoluble cellulose ether membrane

    NASA Technical Reports Server (NTRS)

    Hoyt, H. E.; Pfluger, H. L. (Inventor)

    1969-01-01

    A membrane that is insoluble in an aqueous alkali metal hydroxide medium is described. The membrane is a resin which is a water-soluble C2-C4 hydroxyalkyl cellulose ether polymer and an insolubilizing agent for controlled water sorption, a dialytic and electrodialytic membrane. It is particularly useful as a separator between electrodes or plates in an alkaline storage battery.

  1. Fabrication of nickel-foam-supported layered zinc-cobalt hydroxide nanoflakes for high electrochemical performance in supercapacitors.

    PubMed

    Yuan, Peng; Zhang, Ning; Zhang, Dan; Liu, Tao; Chen, Limiao; Liu, Xiaohe; Ma, Renzhi; Qiu, Guanzhou

    2014-10-04

    Nickel foam supported Zn-Co hydroxide nanoflakes were fabricated by a facile solvothermal method. Benefited from the unique structure of Zn-Co hydroxide nanoflakes on a nickel foam substrate, the as prepared materials exhibited an excellent specific capacitance of 901 F g(-1) at 5 A g(-1) and remarkable cycling stability as electrode materials in supercapacitors.

  2. An advanced Ni-Fe layered double hydroxide electrocatalyst for water oxidation.

    PubMed

    Gong, Ming; Li, Yanguang; Wang, Hailiang; Liang, Yongye; Wu, Justin Z; Zhou, Jigang; Wang, Jian; Regier, Tom; Wei, Fei; Dai, Hongjie

    2013-06-12

    Highly active, durable, and cost-effective electrocatalysts for water oxidation to evolve oxygen gas hold a key to a range of renewable energy solutions, including water-splitting and rechargeable metal-air batteries. Here, we report the synthesis of ultrathin nickel-iron layered double hydroxide (NiFe-LDH) nanoplates on mildly oxidized multiwalled carbon nanotubes (CNTs). Incorporation of Fe into the nickel hydroxide induced the formation of NiFe-LDH. The crystalline NiFe-LDH phase in nanoplate form is found to be highly active for oxygen evolution reaction in alkaline solutions. For NiFe-LDH grown on a network of CNTs, the resulting NiFe-LDH/CNT complex exhibits higher electrocatalytic activity and stability for oxygen evolution than commercial precious metal Ir catalysts.

  3. Synthesis and adsorption properties of flower-like layered double hydroxide by a facile one-pot reaction with an eggshell membrane as assistant

    NASA Astrophysics Data System (ADS)

    Li, Songnan; Zhang, Jiawei; Jamil, Saba; Cai, Qinghai; Zang, Shuying

    In this paper, flower-like layered double hydroxides were synthesized with eggshell membrane assistant. The as-prepared samples were characterized by a series of techniques including X-ray diffraction (XRD), Fourier transform infrared spectroscopy, Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Thermal gravity-differential thermal analysis and Nitrogen sorption/desorption. The resulting layered double hydroxides were composed of nanoplates with edge-to-face particle interactions. The specific surface area and total pore volume of the as-prepared flower-like layered double hydroxides were 160m2/g and 0.65m3/g, respectively. The adsorption capacity of flower-like layered double hydroxides to Congo Red was 258mg/g, which was higher than that of layered double hydroxides synthesized by the traditional method.

  4. Uptake of Au(III) Ions by Aluminum Hydroxide and Their Spontaneous Reduction to Elemental Gold (Au(0)).

    PubMed

    Yokoyama; Matsukado; Uchida; Motomura; Watanabe; Izawa

    2001-01-01

    The behavior of AuCl(4)(-) ions during the formation of aluminum hydroxide at pH 6 was examined. With an increase in NaCl concentration, the content of gold taken up by aluminum hydroxide decreased, suggesting that chloro-hydroxy complexes of Au(III) ion were taken up due to the formation of Al-O-Au bonds. It was found unexpectedly that the Au(III) ions taken up were spontaneously reduced to elemental gold without addition of a specific reducing reagent and then colloidal gold particles were formed. The mechanisms for the uptake of Au(III) ions by aluminum hydroxide and for their spontaneous reduction are discussed. Copyright 2001 Academic Press.

  5. Orosensory responsiveness to and preference for hydroxide-containing salts in mice.

    PubMed

    St John, Steven J; Boughter, John D

    2009-07-01

    Historically, taste researchers have considered the possibility that the gustatory system detects basic compounds, such as those containing the hydroxide ion, but evidence for an "alkaline taste" has not been strong. We found that, in 48 h, 2-bottle preference tests, C3HeB/FeJ (C3) mice showed a preference for Ca(OH)(2), whereas SWR/J (SW) mice showed avoidance. Strain differences were also apparent to NaOH but not CaCl(2). Follow-up studies showed that the strain difference for Ca(OH)(2) was stable over time (Experiment 2) but that C3 and SW mice did not differ in their responses to Ca(OH)(2) or NaOH in brief-access tests, where both mice avoided high concentrations of these compounds (Experiment 3). In order to assess the perceived quality of Ca(OH)(2), mice were tested in 2 taste aversion generalization experiments (Experiments 4 and 5). Aversions to Ca(OH)(2) generalized to NaOH but not CaCl(2) in both strains, suggesting that the generalization was based on the hydroxide ion. Both strains also generalized aversions to quinine, suggesting the possibility that the hydroxide ion has a bitter taste quality to these mice, despite the preference shown by C3 mice to middle concentrations in long-term tests.

  6. Orosensory Responsiveness to and Preference for Hydroxide-Containing Salts in Mice

    PubMed Central

    St. John, Steven J.; Boughter, John D.

    2009-01-01

    Historically, taste researchers have considered the possibility that the gustatory system detects basic compounds, such as those containing the hydroxide ion, but evidence for an “alkaline taste” has not been strong. We found that, in 48 h, 2-bottle preference tests, C3HeB/FeJ (C3) mice showed a preference for Ca(OH)2, whereas SWR/J (SW) mice showed avoidance. Strain differences were also apparent to NaOH but not CaCl2. Follow-up studies showed that the strain difference for Ca(OH)2 was stable over time (Experiment 2) but that C3 and SW mice did not differ in their responses to Ca(OH)2 or NaOH in brief-access tests, where both mice avoided high concentrations of these compounds (Experiment 3). In order to assess the perceived quality of Ca(OH)2, mice were tested in 2 taste aversion generalization experiments (Experiments 4 and 5). Aversions to Ca(OH)2 generalized to NaOH but not CaCl2 in both strains, suggesting that the generalization was based on the hydroxide ion. Both strains also generalized aversions to quinine, suggesting the possibility that the hydroxide ion has a bitter taste quality to these mice, despite the preference shown by C3 mice to middle concentrations in long-term tests. PMID:19423656

  7. Astronauts Newman, Walz and Bursch change out lithium hydroxide canister

    NASA Image and Video Library

    1993-09-20

    STS051-08-037 (12-22 Sept 1993) --- Three members of the astronaut class of 1990 change out a lithium hydroxide canister beneath Discovery's middeck. Left to right are astronauts James H. Newman, Carl E. Walz and Daniel W. Bursch, all mission specialists.

  8. Layered zinc hydroxide nanocones: synthesis, facile morphological and structural modification, and properties

    NASA Astrophysics Data System (ADS)

    Ma, Wei; Ma, Renzhi; Liang, Jianbo; Wang, Chengxiang; Liu, Xiaohe; Zhou, Kechao; Sasaki, Takayoshi

    2014-10-01

    Layered zinc hydroxide nanocones intercalated with DS- have been synthesized for the first time via a convenient synthetic approach, using homogeneous precipitation in the presence of urea and sodium dodecyl sulfate (SDS). SDS plays a significant role in controlling the morphologies of as-synthesized samples. Conical samples intercalated with various anions were transformed through an anion-exchange route in ethanol solution, and the original conical structure was perfectly maintained. Additionally, these DS--inserted nanocones can be transformed into square-like nanoplates in aqueous solution at room temperature, fulfilling the need for different morphology-dependent properties. Corresponding ZnO nanocones and nanoplates have been further obtained through the thermal calcination of NO3--intercalating zinc hydroxide nanocones/nanoplates. These ZnO nanostructures with different morphologies exhibit promising photocatalytic properties.Layered zinc hydroxide nanocones intercalated with DS- have been synthesized for the first time via a convenient synthetic approach, using homogeneous precipitation in the presence of urea and sodium dodecyl sulfate (SDS). SDS plays a significant role in controlling the morphologies of as-synthesized samples. Conical samples intercalated with various anions were transformed through an anion-exchange route in ethanol solution, and the original conical structure was perfectly maintained. Additionally, these DS--inserted nanocones can be transformed into square-like nanoplates in aqueous solution at room temperature, fulfilling the need for different morphology-dependent properties. Corresponding ZnO nanocones and nanoplates have been further obtained through the thermal calcination of NO3--intercalating zinc hydroxide nanocones/nanoplates. These ZnO nanostructures with different morphologies exhibit promising photocatalytic properties. Electronic supplementary information (ESI) available: Typical SEM images, TGA curves and XRD patterns of

  9. A facile one-pot synthesis of ruthenium hydroxide nanoparticles on magnetic silica: Aqueous hydration of nitriles to amides

    EPA Science Inventory

    One-pot synthesis of ruthenium hydroxide nanoparticles on magnetic silica is described which involve the in situ generation of magnetic silica (Fe3O4@ SiO2) and ruthenium hydroxide immobilization; the hydration of nitriles occurs in high yield and excellent selectivity using this...

  10. Continuous-flow extraction system for elemental association study: a case of synthetic metal-doped iron hydroxide.

    PubMed

    Hinsin, Duangduean; Pdungsap, Laddawan; Shiowatana, Juwadee

    2002-12-06

    A continuous-flow extraction system originally developed for sequential extraction was applied to study elemental association of a synthetic metal-doped amorphous iron hydroxide phase. The homogeneity and metal association of the precipitates were evaluated by gradual leaching using the system. Leachate was collected in fractions for determination of elemental concentrations. The result obtained as extractograms indicated that the doped metals were adsorbed more on the outermost surface rather than homogeneously distributed in the precipitates. The continuous-flow extraction method was also used for effective removal of surface adsorbed metals to obtain a homogeneous metal-doped synthetic iron hydroxide by a sequential extraction using acetic acid and small volume of hydroxylamine hydrochloride solution. The system not only ensures complete washing, but the extent of metal immobilization in the synthetic iron hydroxide could be determined with high accuracy from the extractograms. The initial metal/iron mole ratio (M/Fe) in solution affected the M/Fe mole ratio in homogeneous doped iron hydroxide phase. The M/Fe mole ratio of metal incorporation was approximately 0.01-0.02 and 0.03-0.06, for initial solution M/Fe mole ratio of 0.025 and 0.100, respectively.

  11. Chemical matricectomy with 10% sodium hydroxide for the treatment of ingrown toenails in people with diabetes.

    PubMed

    Tatlican, Semih; Eren, Cemile; Yamangokturk, Burcu; Eskioglu, Fatma; Bostanci, Seher

    2010-02-01

    Treatment of ingrown toenails using chemical matricectomy in patients with diabetes has been difficult, because delayed wound healing, wound infections, and digital ischemia can interfere with the procedure. Chemical matricectomy with 10% sodium hydroxide is an effective treatment for ingrown toenails in a normal population. Investigation of the effectiveness and safety of chemical matricectomy with 10% sodium hydroxide solution for ingrown toenails in patients with diabetes. Thirty patients with diabetes with 40 ingrown toenails and 30 patients without diabetes with 41 ingrown toenails were enrolled in the study. After partial avulsion of the affected edge, germinal matrix was treated for 1 minute with 10% sodium hydroxide. Patients were observed on alternate days until complete healing was achieved and followed for up to 24 months for recurrence. Assessment of the treatment in both groups for complete healing, postoperative pain, tissue damage, drainage, infections, and rate of recurrences revealed no statistically significant difference. The partial avulsion of the affected edge and the treatment of the germinal matrix for 1 minute with 10% sodium hydroxide preceded by matrix curettage is an effective and safe treatment modality for ingrown toenails in people with diabetes.

  12. A facile mechanochemical approach to synthesize Zn-Al layered double hydroxide

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Qu, Jun, E-mail: forsjun@whut.edu.cn; He, Xiaoman; Chen, Min

    2017-06-15

    In this study, a mechanochemical route to synthesize Zn-Al layered double hydroxide (LDH) was introduced, in which Zn basic carbonate and Al hydroxide were first dry milled into an activated state and then agitated in water to obtain the final products. The as-prepared samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Thermogravimetry (TG) and Scanning electron microscopy (SEM). The products possessed a high crystallinity of Zn–Al LDH phase without any other impurities, proving a facile and effective preparation of Zn–Al LDH by using non-heating mechanochemical approach. - Highlights: • A non-heating mechanochemical route to synthesize Zn-Almore » LDH. • The products possessed high crystalline Zn-Al LDH phase. • No emission of other impurities or wastewater.« less

  13. Testicular cell population dynamics following palmitine hydroxide treatment in male dogs.

    PubMed

    Gupta, R S; Dixit, V P

    1989-04-01

    Palmitine hydroxide isolated from the roots of Berberis chitria administered orally to dogs 30 mg/kg per day for 60 days brings about a consistent impairment of primary and secondary spermatocytes and elongated spermatids (Stages IV-VIII). The primary and secondary spermatocytes were reduced by 60 and 68%, respectively, and the elongated spermatids were decreased by 58%. The number of spermatogonia and Sertoli cells remained unaltered. The production of immature and mature Leydig cells decreased by 66% and 27%, respectively. Protein, sialic acid and glycogen content and acid phosphatase activity of testes and epididymides were lowered to varying extents. Testicular cholesterol was elevated significantly. Weights of the testes and epididymides were significantly reduced. The antispermatogenic action of palmitine hydroxide may be mediated by disturbances in Leydig cell function.

  14. Cadmium-Aluminum Layered Double Hydroxide Microspheres for Photocatalytic CO2 Reduction.

    PubMed

    Saliba, Daniel; Ezzeddine, Alaa; Sougrat, Rachid; Khashab, Niveen M; Hmadeh, Mohamad; Al-Ghoul, Mazen

    2016-04-21

    We report the synthesis of cadmium-aluminum layered double hydroxide (CdAl LDH) using the reaction-diffusion framework. As the hydroxide anions diffuse into an agar gel matrix containing the mixture of aluminum and cadmium salts at a given ratio, they react to give the LDH. The LDH self-assembles inside the pores of the gel matrix into a unique spherical-porous shaped microstructure. The internal and external morphologies of the particles are studied by electron microscopy and tomography revealing interconnected channels and a high surface area. This material is shown to exhibit a promising performance in the photoreduction of carbon dioxide using solar light. Moreover, the palladium-decorated version shows a significant improvement in its reduction potential at room temperature. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. The origin of 2.7 eV luminescence and 5.2 eV excitation band in hafnium oxide

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Perevalov, T. V., E-mail: timson@isp.nsc.ru; Novosibirsk State University, 2 Pirogova St., 630090 Novosibirsk; Aliev, V. Sh.

    2014-02-17

    The origin of a blue luminescence band at 2.7 eV and a luminescence excitation band at 5.2 eV of hafnia has been studied in stoichiometric and non-stoichiometric hafnium oxide films. Experimental and calculated results from the first principles valence band spectra showed that the stoichiometry violation leads to the formation of the peak density of states in the band gap caused by oxygen vacancies. Cathodoluminescence in the non-stoichiometric film exhibits a band at 2.65 eV that is excited at the energy of 5.2 eV. The optical absorption spectrum calculated for the cubic phase of HfO{sub 2} with oxygen vacancies showsmore » a peak at 5.3 eV. Thus, it could be concluded that the blue luminescence band at 2.7 eV and HfO{sub x} excitation peak at 5.2 eV are due to oxygen vacancies. The thermal trap energy in hafnia was estimated.« less

  16. IER-297 CED-2: Final Design for Thermal/Epithermal eXperiments with Jemima Plates with Polyethylene and Hafnium

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Nelson, A. J.; Percher, C. M.; Zywiec, W. J.

    This report presents the final design (CED-2) for IER-297, and focuses on 15 critical configurations using highly enriched uranium (HEU) Jemima plates moderated by polyethylene with and without hafnium diluent. The goal of the U.S. Nuclear Criticality Safety Program’s Thermal/Epithermal eXperiments (TEX) is to design and conduct new critical experiments to address high priority nuclear data needs from the nuclear criticality safety and nuclear data communities, with special emphasis on intermediate energy (0.625 eV – 100 keV) assemblies that can be easily modified to include various high priority diluent materials. The TEX (IER 184) CED-1 Report [1], completed in 2012,more » demonstrated the feasibility of meeting the TEX goals with two existing NCSP fissile assets, plutonium Zero Power Physics Reactor (ZPPR) plates and highly enriched uranium (HEU) Jemima plates. The first set of TEX experiments will focus on using the plutonium ZPPR plates with polyethylene moderator and tantalum diluents.« less

  17. Flare-ups incidence and severity after using calcium hydroxide as intracanal dressing.

    PubMed

    Ghoddusi, Jamileh; Javidi, Maryam; Zarrabi, Mohammad Hasan; Bagheri, Hossein

    2006-01-01

    Acute pain and swelling following endodontic treatment are a challenge for both the patient and the dentist. According to previous studies, the incidence of flare-ups increases after endodontic treatment of teeth with necrotic pulps. Calcium hydroxide is currently used as a multi-purpose drug in root canal therapy. The aim of this study was to evaluate the incidence and severity of flare-ups after treatment of pulpless teeth using calcium hydroxide as an intracanal dressing. Sixty patients with single-root necrotic teeth participated in this study. These patients were randomly divided into three groups of 20. The patients were treated in Group A in a single-visit approach, in group B with a two-visit approach without any intracanal dressing and group C with a two-visit approach using calcium hydroxide as an intracanal dressing for one week. All of the patients were followed for 72 hours after each treatment session. The information about the incidence and severity of pain and swelling was recorded in tables, using a modified Visual Analogue Scale for pain severity measurement and a scale with four degrees for measuring the severity of swelling. The data were analyzed by chi-square test and GENMODE procedure.

  18. New metal phthalocyanines/metal simple hydroxide multilayers: experimental evidence of dipolar field-driven magnetic behavior.

    PubMed

    Bourzami, Riadh; Eyele-Mezui, Séraphin; Delahaye, Emilie; Drillon, Marc; Rabu, Pierre; Parizel, Nathalie; Choua, Sylvie; Turek, Philippe; Rogez, Guillaume

    2014-01-21

    A series of new hybrid multilayers has been synthesized by insertion-grafting of transition metal (Cu(II), Co(II), Ni(II), and Zn(II)) tetrasulfonato phthalocyanines between layers of Cu(II) and Co(II) simple hydroxides. The structural and spectroscopic investigations confirm the formation of new layered hybrid materials in which the phthalocyanines act as pillars between the inorganic layers. The magnetic investigations show that all copper hydroxide-based compounds behave similarly, presenting an overall antiferromagnetic behavior with no ordering down to 1.8 K. On the contrary, the cobalt hydroxide-based compounds present a ferrimagnetic ordering around 6 K, regardless of the nature of the metal phthalocyanine between the inorganic layers. The latter observation points to strictly dipolar interactions between the inorganic layers. The amplitude of the dipolar field has been evaluated from X-band and Q-band EPR spectroscopy investigation (Bdipolar ≈ 30 mT).

  19. Studies on Thorium Adsorption Characteristics upon Activated Titanium Hydroxide Prepared from Rosetta Ilmenite Concentrate

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gado, M, E-mail: parq28@yahoo.com; Zaki, S

    2016-01-01

    The titanium hydroxide prepared from Rosetta ilmenite concentrate has been applied for Th (IV) adsorption from its acid aqueous solutions. The prepared hydroxide is first characterized by both Fourier transform infrared (FT-IR) spectrum and thermogravimetric analysis. The relevant factors affecting the adsorption process have been studied. The obtained equilibrium data fits well with the Langmuir isotherm rather than Freundlich isotherm, while the adsorption kinetic data follow the pseudo-second order model. The different thermodynamic parameters have also been calculated and indicate that the adsorption process is spontaneous.

  20. An improved method for analysis of hydroxide and carbonate in alkaline electrolytes containing zinc

    NASA Technical Reports Server (NTRS)

    Reid, M. A.

    1978-01-01

    A simplified method for titration of carbonate and hydroxide in alkaline battery electrolyte is presented involving a saturated KSCN solution as a complexing agent for zinc. Both hydroxide and carbonate can be determined in one titration, and the complexing reagent is readily prepared. Since the pH at the end point is shifted from 8.3 to 7.9-8.0, m-cresol purple or phenol red are used as indicators rather than phenolphthalein. Bromcresol green is recommended for determination of the second end point of a pH of 4.3 to 4.4.

  1. An improved method for analysis of hydroxide and carbonate in alkaline electrolytes containing zinc

    NASA Technical Reports Server (NTRS)

    Reid, M. A.

    1978-01-01

    A simplified method for titration of carbonate and hydroxide in alkaline battery electrolyte is presented involving a saturated KSCN solution as a complexing agent for zinc. Both hydroxide and carbonate can be determined in one titration, and the complexing reagent is readily prepared. Since the pH at the end point is shifted from 8.3 to 7.9 - 8.0, m-cresol purple or phenol red are used as indicators rather than phenolphthalein. Bromcresol green is recommended for determination of the second end point of a pH of 4.3 to 4.4.

  2. Subnanometer Cobalt-Hydroxide-Anchored N-Doped Carbon Nanotube Forest for Bifunctional Oxygen Catalyst.

    PubMed

    Kim, Ji Eun; Lim, Joonwon; Lee, Gil Yong; Choi, Sun Hee; Maiti, Uday Narayan; Lee, Won Jun; Lee, Ho Jin; Kim, Sang Ouk

    2016-01-27

    Electrochemical oxygen redox reactions are the crucial elements for energy conversion and storage including fuel cells and metal air batteries. Despite tremendous research efforts, developing high-efficient, low-cost, and durable bifunctional oxygen catalysts remains a major challenge. We report a new class of hybrid material consisting of subnanometer thick amorphous cobalt hydroxide anchored on NCNT as a durable ORR/OER bifunctional catalyst. Although amorphous cobalt species-based catalysts are known as good OER catalysts, hybridizing with NCNT successfully enhanced ORR activity by promoting a 4e reduction pathway. Abundant charge carriers in amorphous cobalt hydroxide are found to trigger the superior OER activity with high current density and low Tafel slope as low as 36 mV/decade. A remarkably high OER turnover frequency (TOF) of 2.3 s(-1) at an overpotential of 300 mV was obtained, one of the highest values reported so far. Moreover, the catalytic activity was maintained over 120 h of cycling. The unique subnanometer scale morphology of amorphous hydroxide cobalt species along with intimate cobalt species-NCNT interaction minimizes the deactivation of catalyst during prolonged repeated cycles.

  3. Synthesis of transparent dispersions of aluminium hydroxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Chen, Bo; Wang, Jie-Xin; Wang, Dan; Zeng, Xiao-Fei; Clarke, Stuart M.; Chen, Jian-Feng

    2018-07-01

    Transparent dispersions of inorganic nanoparticles are attractive materials in many fields. However, a facile method for preparing such dispersions of aluminium hydroxide nanoparticles is yet to be realized. Here, we report a direct reactive method to prepare transparent dispersions of pseudo-boehmite nanoparticles (1 wt%) without any surface modification, and with an average particle size of 80 nm in length and 10 nm in width, as well as excellent optical transparency over 94% in the visible range. Furthermore, transparent dispersions of boehmite nanoparticles (1.5 wt%) were also achieved after an additional hydrothermal treatment. However, the optical transparency of dispersions decreased with the rise of hydrothermal temperature and the shape of particles changed from rhombs to hexagons. In particular, monodisperse hexagonal boehmite nanoplates with an average lateral size of 58 nm and a thickness of 12.5 nm were obtained at a hydrothermal temperature of 220 °C. The selectivity of crystal growth direction was speculated as the possible formation mechanism of these as-prepared aluminium hydroxide nanoparticles. Besides, two values of 19.6 wt% and 14.64 wt% were separately measured for the weight loss of pseudo-boehmite and boehmite nanoparticles after a continuous heating, indicating their potential flame-resistant applications in the fabrication of plastic electronics and optical devices with high transparency.

  4. Synthesis of transparent dispersions of aluminium hydroxide nanoparticles.

    PubMed

    Chen, Bo; Wang, Jie-Xin; Wang, Dan; Zeng, Xiao-Fei; Clarke, Stuart M; Chen, Jian-Feng

    2018-07-27

    Transparent dispersions of inorganic nanoparticles are attractive materials in many fields. However, a facile method for preparing such dispersions of aluminium hydroxide nanoparticles is yet to be realized. Here, we report a direct reactive method to prepare transparent dispersions of pseudo-boehmite nanoparticles (1 wt%) without any surface modification, and with an average particle size of 80 nm in length and 10 nm in width, as well as excellent optical transparency over 94% in the visible range. Furthermore, transparent dispersions of boehmite nanoparticles (1.5 wt%) were also achieved after an additional hydrothermal treatment. However, the optical transparency of dispersions decreased with the rise of hydrothermal temperature and the shape of particles changed from rhombs to hexagons. In particular, monodisperse hexagonal boehmite nanoplates with an average lateral size of 58 nm and a thickness of 12.5 nm were obtained at a hydrothermal temperature of 220 °C. The selectivity of crystal growth direction was speculated as the possible formation mechanism of these as-prepared aluminium hydroxide nanoparticles. Besides, two values of 19.6 wt% and 14.64 wt% were separately measured for the weight loss of pseudo-boehmite and boehmite nanoparticles after a continuous heating, indicating their potential flame-resistant applications in the fabrication of plastic electronics and optical devices with high transparency.

  5. Alternative Sodium Recovery Technology—High Hydroxide Leaching: FY10 Status Report

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Mahoney, Lenna A.; Neiner, Doinita; Peterson, Reid A.

    2011-02-04

    Boehmite leaching tests were carried out at NaOH concentrations of 10 M and 12 M, temperatures of 85°C and 60°C, and a range of initial aluminate concentrations. These data, and data obtained during earlier 100°C tests using 1 M and 5 M NaOH, were used to establish the dependence of the boehmite dissolution rate on hydroxide concentration, temperature, and initial aluminate concentration. A semi-empirical kinetic model for boehmite leaching was fitted to the data and used to calculate the NaOH additions required for leaching at different hydroxide concentrations. The optimal NaOH concentration for boehmite leaching at 85°C was estimated, basedmore » on minimizing the amount of Na that had to be added in NaOH to produce a given boehmite conversion.« less

  6. Photoluminescence properties of Eu3+ doped HfO2 coatings formed by plasma electrolytic oxidation of hafnium

    NASA Astrophysics Data System (ADS)

    Stojadinović, Stevan; Tadić, Nenad; Ćirić, Aleksandar; Vasilić, Rastko

    2018-03-01

    Plasma electrolytic oxidation was used for synthesis of Eu3+ doped monoclinic HfO2 coatings on hafnium substrate. Results of photoluminescence (PL) measurements show the existence of two distinct regions: one that is related to the blue emission originating from oxygen vacancy defects in HfO2 and the other one characterized with a series of sharp orange-red emission peaks related to f-f transitions of Eu3+ from excited level 5D0 to lower levels 7FJ (J = 0, 1, 2, 3, and 4). PL peaks appearing in excitation spectra of obtained coatings are attributed either to charge transfer state of Eu3+ or to direct excitation of the Eu3+ ground state 7F0 into higher levels of the 4f-manifold. PL of formed coatings increases with PEO time due to an increase of oxygen vacancy defects and the content of Eu3+. Acquired experimental data suggest that hypersensitive electrical dipole transition is much more intense than the magnetic dipole transition, indicating that Eu3+ ions occupy a non-inversion symmetry sites.

  7. Permanence and diffusion of borax-copper hydroxide remedial preservative applied to unseasoned pine posts : 10 year update

    Treesearch

    Douglas Crawford; Stan Lebow; Mike West; Bill Abbott

    2005-01-01

    In 1993, unseasoned pine posts were treated with groundline remedial treatment containing 3.1% copper hydroxide and 40% sodium tetraborate decahydrate (borax). The soundness of the posts was periodically evaluated using a push test. After 3.5, 6.5, and 10 years, sections were taken from two posts to determine retention of borax and copper hydroxide below ground to 36...

  8. An empirical model to estimate density of sodium hydroxide solution: An activator of geopolymer concretes

    NASA Astrophysics Data System (ADS)

    Rajamane, N. P.; Nataraja, M. C.; Jeyalakshmi, R.; Nithiyanantham, S.

    2016-02-01

    Geopolymer concrete is zero-Portland cement concrete containing alumino-silicate based inorganic polymer as binder. The polymer is obtained by chemical activation of alumina and silica bearing materials, blast furnace slag by highly alkaline solutions such as hydroxide and silicates of alkali metals. Sodium hydroxide solutions of different concentrations are commonly used in making GPC mixes. Often, it is seen that sodium hydroxide solution of very high concentration is diluted with water to obtain SHS of desired concentration. While doing so it was observed that the solute particles of NaOH in SHS tend to occupy lower volumes as the degree of dilution increases. This aspect is discussed in this paper. The observed phenomenon needs to be understood while formulating the GPC mixes since this influences considerably the relationship between concentration and density of SHS. This paper suggests an empirical formula to relate density of SHS directly to concentration expressed by w/w.

  9. Encapsulation of sulfur with thin-layered nickel-based hydroxides for long-cyclic lithium–sulfur cells

    PubMed Central

    Jiang, Jian; Zhu, Jianhui; Ai, Wei; Wang, Xiuli; Wang, Yanlong; Zou, Chenji; Huang, Wei; Yu, Ting

    2015-01-01

    Elemental sulfur cathodes for lithium/sulfur cells are still in the stage of intensive research due to their unsatisfactory capacity retention and cyclability. The undesired capacity degradation upon cycling originates from gradual diffusion of lithium polysulfides out of the cathode region. To prevent losses of certain intermediate soluble species and extend lifespan of cells, the effective encapsulation of sulfur plays a critical role. Here we report an applicable way, by using thin-layered nickel-based hydroxide as a feasible and effective encapsulation material. In addition to being a durable physical barrier, such hydroxide thin films can irreversibly react with lithium to generate protective layers that combine good ionic permeability and abundant functional polar/hydrophilic groups, leading to drastic improvements in cell behaviours (almost 100% coulombic efficiency and negligible capacity decay within total 500 cycles). Our present encapsulation strategy and understanding of hydroxide working mechanisms may advance progress on the development of lithium/sulfur cells for practical use. PMID:26470847

  10. The effect of metal (hydr)oxide nano-enabling on intraparticle mass transport of organic contaminants in hybrid granular activated carbon.

    PubMed

    Garcia, Jose; Markovski, Jasmina; McKay Gifford, J; Apul, Onur; Hristovski, Kiril D

    2017-05-15

    The overarching goal of this study was to ascertain the changes in intraparticle mass transport rates for organic contaminants resulting from nano-enabled hybridization of commercially available granular activated carbon (GAC). Three different nano-enabled hybrid media were fabricated by in-situ synthesizing titanium dioxide nanoparticles inside the pores of GAC sorbent, characterized, and evaluated for removal of two model organic contaminants under realistic conditions to obtain the intraparticle mass transport (pore and surface diffusion) coefficients. The results validated the two hypotheses that: (H1) the pore diffusion rates of organic contaminants linearly decrease with decrease in cumulative pore volume caused by increase in metal (hydr)oxide nanoparticle content inside the pores of the hybrid GAC sorbent; and (H2) introduction of metal (hydr)oxide nanoparticles initially increases surface diffusivity, but additional loading causes its decrease as the increase in metal (hydr)oxide nanoparticles content continues to reduce the porosity of the GAC sorbent. Nano-enabled hybridization of commercially available GAC with metal (hydr)oxides has the potential to significantly increase the intraparticle mass transport limitations for organic contaminants. Introduction of metal (hydr)oxide nanoparticles inside the pores of a pristine sorbent causes the pore diffusion rates of organic contaminants to decrease as the cumulative pore volume is reduced. In contrast, the introduction of limited amounts of metal (hydr)oxide nanoparticles appears to facilitate the surface diffusion rates of these contaminants. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. A facile one-pot synthesis of ruthenium hydroxide nanoparticles on magnetic silica: aqueous hydration of nitriles to amides.

    PubMed

    Baig, R B Nasir; Varma, Rajender S

    2012-06-25

    One-pot synthesis of ruthenium hydroxide nanoparticles on magnetic silica is described which involves the in situ generation of magnetic silica (Fe(3)O(4)@SiO(2)) and ruthenium hydroxide immobilization; the hydration of nitriles occurs in high yield and excellent selectivity using this catalyst which proceeds exclusively in aqueous medium under neutral conditions.

  12. Rare earth and zinc layered hydroxide salts intercalated with the 2-aminobenzoate anion as organic luminescent sensitizer

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cursino, Ana Cristina Trindade, E-mail: anacursino@ufpr.br; Rives, Vicente, E-mail: vrives@usal.es; Arizaga, Gregorio Guadalupe Carbajal, E-mail: gregoriocarbajal@yahoo.com.mx

    2015-10-15

    Rare earth (RE = Eu, Y and Tb) and zinc layered hydroxide salts intercalated with nitrate anions were synthesized, followed by exchange with 2-aminobenzoate. The UV absorption ability was improved after intercalation/grafting in relation to that shown by the parent material. - Highlights: • Rare earth (RE = Eu, Y and Tb) and zinc layered hydroxide were synthesized. • Intercalated nitrate anions were exchanged by 2-aminobenzoate. • In all the 2-aminobenzoate containing compounds, the grafting reaction was detected. • The UV absorption ability was improved after the exchange reactions. • Rare earth hydroxide salts are potential matrixes to produce luminescentmore » materials. - Abstract: Rare earth (RE = Eu, Y and Tb) and zinc layered hydroxide salts intercalated with nitrate anions were synthesized, followed by exchange with 2-aminobenzoate. The obtained compounds were characterized by powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR) and ultraviolet visible (UV–vis) spectroscopies, fluorescence measurements and thermal analysis (TGA/DTA). The results from FTIR spectroscopy suggest a direct coordination of 2-aminobenzoate to the metal cations of the inorganic layered structure. The organic derivative products from the intercalation reactions absorb a broader range of UV-light in relation to that shown by the parent material; the photoluminescence measurements present a strong violet, blue and green luminescence under UV-light excitation for layered compounds with, Zn, Y and Tb, respectively. Rare earth hydroxide salts (RE-LHS) are potential alternative matrices for the immobilization of organic species to produce luminescent materials.« less

  13. Butanolysis: Comparison of potassium hydroxide and potassium tert-butoxide as catalyst for biodiesel preparing from rapeseed oil.

    PubMed

    Musil, Martin; Skopal, Frantisek; Hájek, Martin; Vavra, Ales

    2018-07-15

    Biodiesel is a mixture of esters of fatty acids (most often palmitic, stearic and oleic) and lower alcohols (in our work butanol) produced by transesterification. It is a renewable source of energy, prepared from triacylglycerides, which are contained in vegetable oils and animal fats. This work focuses on alkaline catalyzed transesterification of rapeseed oil with butanol and comparison of two catalysts (potassium hydroxide and potassium tert-butoxide). In industry is usually transesterification of rapeseed oil carried out like reaction catalyzed by potassium hydroxide. Potassium hydroxide have high content of K 2 CO 3 , KHCO 3 and water. Moreover water is formed by neutralization of potassium hydroxide with free fatty acids contained in oil. In cause of tert-butoxide catalyzed reaction, it is not possible because tert-butoxide have not a OH - aniont, which is needed for water forming. The influence of various conditions (addition of water, temperature of separation, intensity of stirring and type of catalyst) on butanolysis process was studied for both catalysts. For both catalysts dependence of conversions on time were plotted. When tert-butoxide was used, satisfactory phase separation was not achieved. The only way was separation of hot crude reaction mixture without adding water. Ester formed by this method had high content of free glycerol and soaps, but reached higher conversion. The best results were obtained with KOH and subsequent separation of cold crude reaction mixture with the addition of water and slow stirring. The difference between reactions catalyzed by potassium hydroxide and potassium tert-butoxide was described. Copyright © 2018 Elsevier Ltd. All rights reserved.

  14. Thermomechanical and Thermochemical Behavior of a Hafnium-20 Percent Tantalum Alloy. Ph.D. Thesis - North Carolina State Univ., Raleigh

    NASA Technical Reports Server (NTRS)

    Howell, J. P.

    1971-01-01

    An investigation was conducted to determine the thermomechanical and thermochemical behavior of a high temperature, oxidation resistant, hafnium-20 percent tantalum alloy. The elastic and shear moduli of this alloy were determined in air up to 1000 C and in vacuum up to 2000 C using a mechanical resonance technique. The internal friction of the alloy was measured up to temperatures greater than 1400 C. Room temperature stress-strain behavior of the oxidized and unoxidized alloy was established. The effect of annealing on the elastic and shear moduli of the extruded rod material was investigated. The martensitic-type phase transformation occurring in the alloy was studied using hot stage metallography and electron microscopy. Static oxidation tests were conducted on the alloy at temperatures from 1000 C to 1700 C with weight gain measurements made as a function of time and temperatures. Surface morphology studies were conducted on the oxide coatings formed at the different temperatures using scanning electron microscopy and X-ray diffraction techniques.

  15. Titration of Monoprotic Acids with Sodium Hydroxide Contaminated by Sodium Carbonate.

    ERIC Educational Resources Information Center

    Michalowski, Tadeusz

    1988-01-01

    Discusses the effects of using carbon dioxide contaminated sodium hydroxide solution as a titrant for a solution of a weak monoprotic acid and the resulting distortion of the titration curve in comparison to one obtained when an uncontaminated titrant is used. (CW)

  16. The relationship between structural stability and electrochemical performance of multi-element doped alpha nickel hydroxide

    NASA Astrophysics Data System (ADS)

    Miao, Chengcheng; Zhu, Yanjuan; Huang, Liangguo; Zhao, Tengqi

    2015-01-01

    The multi-element doped alpha nickel hydroxide has been prepared by supersonic co-precipitation method. Three kinds of samples A, B and C are prepared by chemically coprecipitating Ni/Al, Ni/Al/Mn and Ni/Al/Mn/Yb, respectively. Inductively coupled plasma atomic emission spectroscopy (ICP-AES), Particle size distribution (PSD) measurement, X-ray diffraction (XRD), scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FT-IR) are used to characterize the physical properties of the synthesized α-Ni(OH)2 samples, such as chemical composition, morphology, structural stability of the crystal. The results show that all samples are nano-sized materials and the interlayer spacing becomes larger and the structural stability becomes better with the increase of doped elements and doped ratio. The prepared alpha nickel hydroxide samples are added into micro-sized beta nickel hydroxide to form biphase electrode materials for Ni-MH battery. The electrochemical characterization of the biphase electrodes, including cyclic voltammetry (CV) and charge/discharge test, are also performed. The results demonstrate that the biphase electrode with sample C exhibits better electrochemical reversibility and cyclic stability, higher charge efficient and discharge potential, larger proton diffusion coefficient (5.81 × 10-12 cm2 s-1) and discharge capacity (309.0 mAh g-1). Hence, it indicates that all doped elements can produce the synergic effect and further improve the electrochemical properties of the alpha nickel hydroxide.

  17. Autopsy results of a case of ingestion of sodium hydroxide solution.

    PubMed

    Emoto, Yuko; Yoshizawa, Katsuhiko; Shikata, Nobuaki; Tsubura, Airo; Nagasaki, Yasushi

    2016-01-01

    Sodium hydroxide is a strongly corrosive alkali. We describe herein a case of suicide by ingestion of sodium hydroxide. A man in his 80s was found dead with a mug and a bottle of caustic soda. Macroscopically, liquefaction and/or disappearance of esophagus, trachea and lung tissue and a grayish discoloration of the mucosa of the stomach were seen along with blackish brown coloration of the skin, mouth, and oral cavity. The contents of the gastrointestinal tract showed a pH level of 7-8 on pH indicator strips. Histopathologically, liquefactive necrosis of remnant lung tissue and the stomach were seen. As biological reactions such as vasodilatation and inflammation were not detected in these organs, only a short number of hours must have passed between ingestion and death. This human case provides valuable information concerning the direct irritation induced by systemic exposure to corrosive substances.

  18. Engineering evaluation of a sodium hydroxide thermal energy storage module

    NASA Technical Reports Server (NTRS)

    Perdue, D. G.; Gordon, L. H.

    1980-01-01

    An engineering evaluation of thermal energy storage prototypes was performed in order to assess the development status of latent heat storage media. The testing and the evaluation of a prototype sodium hydroxide module is described. This module stored off-peak electrical energy as heat for later conversion to domestic hot water needs.

  19. Periodicity in the Acid-Base Behavior of Oxides and Hydroxides.

    ERIC Educational Resources Information Center

    Rich, Ronald L.

    1985-01-01

    Aqueous solubilities of many important hydrous oxides and hydroxides are displayed, for the various elements, as functions primarily of pH. These graphs are then arranged in groups to facilitate studies of the effects of oxidation state, electron structure, and position in the periodic table, along with size and coordination number. (JN)

  20. Synthesis, structure refinement and chromate sorption characteristics of an Al-rich bayerite-based layered double hydroxide

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Britto, Sylvia, E-mail: sylviabritto11@gmail.com; Kamath, P. Vishnu

    2014-07-01

    “Imbibition” of Zn{sup 2+} ions into the cation vacancies of bayerite–Al(OH){sub 3} and NO{sub 3}{sup −} ions into the interlayer gallery yields an Al-rich layered double hydroxide with Al/Zn ratio ∼3. NO{sub 3}{sup −} ions are intercalated with their molecular planes inclined at an angle to the plane of the metal hydroxide slab and bonded to it by hydrogen bonds. Rietveld refinement of the structure shows that the monoclinic symmetry of the precursor bayerite is preserved in the product, showing that the imbibition is topochemical in nature. The nitrate ion is labile and is quantitatively replaced by CrO{sub 4}{sup 2−}more » ions from solution. The uptake of CrO{sub 4}{sup 2−} ions follows a Langmuir adsorption isotherm, thus showing that the hydroxide is a candidate material for green chemistry applications for the removal of CrO{sub 4}{sup 2−} ions from waste water. Rietveld refinement of the structure of the hydroxide after CrO{sub 4}{sup 2−} inclusion reveals that the CrO{sub 4}{sup 2−} ion is intercalated with one of its 2-fold axes parallel to the b-crystallographic axis of the crystal, also the principal 2 axis of the monoclinic cell. - Graphical abstract: The structure of the [Zn–Al4-nitrate] LDH viewed along the a-axis. - Highlights: • Synthesis of Al-rich layered double hydroxide with Al/Zn ratio ∼3. • Rietveld refinement indicates that the imbibition of Zn into Al(OH){sub 3} is topochemical in nature. • The uptake of CrO{sub 4}{sup 2−} ions follows a Langmuir adsorption isotherm.« less

  1. Fabrication of porous low crystalline calcite block by carbonation of calcium hydroxide compact.

    PubMed

    Matsuya, Shigeki; Lin, Xin; Udoh, Koh-ichi; Nakagawa, Masaharu; Shimogoryo, Ryoji; Terada, Yoshihiro; Ishikawa, Kunio

    2007-07-01

    Calcium carbonate (CaCO(3)) has been widely used as a bone substitute material because of its excellent tissue response and good resorbability. In this experimental study, we propose a new method obtaining porous CaCO(3) monolith for an artificial bone substitute. In the method, calcium hydroxide compacts were exposed to carbon dioxide saturated with water vapor at room temperature. Carbonation completed within 3 days and calcite was the only product. The mechanical strength of CaCO(3) monolith increased with carbonation period and molding pressure. Development of mechanical strength proceeded through two steps; the first rapid increase by bonding with calcite layer formed at the surface of calcium hydroxide particles and the latter increase by the full conversion of calcium hydroxide to calcite. The latter process was thought to be controlled by the diffusion of CO(2) through micropores in the surface calcite layer. Porosity of calcite blocks thus prepared had 36.8-48.1% depending on molding pressure between 1 MPa and 5 MPa. We concluded that the present method may be useful for the preparation of bone substitutes or the preparation of source material for bone substitutes since this method succeeded in fabricating a low-crystalline, and thus a highly reactive, porous calcite block.

  2. A prospective, open, comparative study of 5% potassium hydroxide solution versus cryotherapy in the treatment of genital warts in men*

    PubMed Central

    Camargo, Caio Lamunier de Abreu; Belda, Walter; Fagundes, Luiz Jorge; Romiti, Ricardo

    2014-01-01

    BACKGROUND Genital warts are caused by human papillomavirus infection and represent one of the most common sexually transmitted diseases. Many infections are transient but the virus may recur, persist, or become latent. To date, there is no effective antiviral treatment to eliminate HPV infection and most therapies are aimed at the destruction of visible lesions. Potassium hydroxide is a strong alkali that has been shown to be safe and effective for the treatment of genital warts and molluscum contagiosum. Cryotherapy is considered one of the most established treatments for genital warts. No comparative trials have been reported to date on the use of potassium hydroxide for genital warts. OBJECTIVE A prospective, open-label, randomized clinical trial was conducted to compare topical potassium hydroxide versus cryotherapy in the treatment of genital warts affecting immunocompetent, sexually active men. METHODS Over a period of 10 months, 48 patients were enrolled. They were randomly divided into two groups and selected on an alternative basis for either potassium hydroxide therapy or cryotherapy. While response to therapy did not differ substantially between both treatment modalities, side effects such as local pain and post-treatment hypopigmentation were considerably more prevalent in the groups treated using cryotherapy. RESULT In our study, potassium hydroxide therapy proved to be at least as effective as cryotherapy and offered the benefit of a better safety profile. CONCLUSION Topical 5% potassium hydroxide presents an effective, safe, and low-cost treatment modality for genital warts in men and should be included in the spectrum of therapies for genital warts. PMID:24770498

  3. A prospective, open, comparative study of 5% potassium hydroxide solution versus cryotherapy in the treatment of genital warts in men.

    PubMed

    Camargo, Caio Lamunier de Abreu; Belda Junior, Walter; Fagundes, Luiz Jorge; Romiti, Ricardo

    2014-01-01

    Genital warts are caused by human papillomavirus infection and represent one of the most common sexually transmitted diseases. Many infections are transient but the virus may recur, persist, or become latent. To date, there is no effective antiviral treatment to eliminate HPV infection and most therapies are aimed at the destruction of visible lesions. Potassium hydroxide is a strong alkali that has been shown to be safe and effective for the treatment of genital warts and molluscum contagiosum. Cryotherapy is considered one of the most established treatments for genital warts. No comparative trials have been reported to date on the use of potassium hydroxide for genital warts. A prospective, open-label, randomized clinical trial was conducted to compare topical potassium hydroxide versus cryotherapy in the treatment of genital warts affecting immunocompetent, sexually active men. Over a period of 10 months, 48 patients were enrolled. They were randomly divided into two groups and selected on an alternative basis for either potassium hydroxide therapy or cryotherapy. While response to therapy did not differ substantially between both treatment modalities, side effects such as local pain and post-treatment hypopigmentation were considerably more prevalent in the groups treated using cryotherapy. In our study, potassium hydroxide therapy proved to be at least as effective as cryotherapy and offered the benefit of a better safety profile. Topical 5% potassium hydroxide presents an effective, safe, and low-cost treatment modality for genital warts in men and should be included in the spectrum of therapies for genital warts.

  4. Iron Hydroxide Minerals Drive Organic and Phosphorus Chemistry in Subsurface Redox / pH Gradients

    NASA Astrophysics Data System (ADS)

    Flores, E.; Barge, L. M.; VanderVelde, D.; Baum, M.

    2017-12-01

    Iron minerals, particularly iron oxides and oxyhydroxides, are prevalent on Mars and may exist in mixed valence or even reduced states beneath the oxidized surface. Iron (II,III) hydroxides, including green rust, are reactive and potentially catalytic minerals that can absorb and concentrate charged species, while also driving chemical reactions. These minerals are highly redox-sensitive and the presence of organics and/or phosphorus species could affect their mineralogy and/or stability. Conversely, the minerals might be able to drive chemical processes such as amino acid formation, phosphorus oxyanion reactions, or could simply selectively preserve organic species via surface adsorption. In an open aqueous sediment column, soluble products of mineral-driven reactions could also diffuse to sites of different chemical conditions to react even further. We synthesized Fe-hydroxide minerals under various conditions relevant to early Earth and ancient Mars (>3.0 Gyr), anoxically and in the presence of salts likely to have been present in surface or ground waters. Using these minerals we conducted experiments to test whether iron hydroxides could promote amino acid formation, and how the reaction is affected by subsurface gradients of redox, pH, and temperature. We also tested the adsorption of organic and phosphorus species onto Fe-hydroxide minerals at different conditions within the gradients. The suite of organic or phosphorus signatures that may be found in a particular mineral system is a combination of what is synthesized there, what is preferentially concentrated / retained there, and what is preserved against degradation. Further work is needed to determine how these processes could have proceeded on Mars and what mineral-organic signatures, abiotic or otherwise, would be produced from such processes.

  5. Synthesis, characterization, and efficacy of antituberculosis isoniazid zinc aluminum-layered double hydroxide based nanocomposites

    PubMed Central

    Saifullah, Bullo; El Zowalaty, Mohamed Ezzat; Arulselvan, Palanisamy; Fakurazi, Sharida; Webster, Thomas J; Geilich, Benjamin Mahler; Hussein, Mohd Zobir

    2016-01-01

    The chemotherapy for tuberculosis (TB) is complicated by its long-term treatment, its frequent drug dosing, and the adverse effects of anti-TB drugs. In this study, we have developed two nanocomposites (A and B) by intercalating the anti-TB drug isoniazid (INH) into Zn/Al-layered double hydroxides. The average size of the nanocomposites was found to bê164 nm. The efficacy of the Zn/Al-layered double hydroxides intercalated INH against Mycobacterium tuberculosis was increased by approximately three times more than free INH. The nanocomposites were also found to be active against Gram-positive and -negative bacteria. Compared to the free INH, the nanodelivery formulation was determined to be three times more biocompatible with human normal lung fibroblast MRC-5 cells and 3T3 fibroblast cells at a very high concentration of 50 µg/mL for up to 72 hours. The in vitro release of INH from the Zn/Al-layered double hydroxides was found to be sustained in human body-simulated buffer solutions of pH 4.8 and 7.4. This research is a step forward in making the TB chemotherapy patient friendly. PMID:27486322

  6. Optical properties of cerium oxide (CeO2) nanoparticles synthesized by hydroxide mediated method

    NASA Astrophysics Data System (ADS)

    Ali, Mawlood Maajal; Mahdi, Hadeel Salih; Parveen, Azra; Azam, Ameer

    2018-05-01

    The nanoparticles of cerium oxide have been successfully synthesized by hydroxide mediated method, using cerium nitrate and sodium hydroxide as precursors. The microstructural properties were analyzed by X-ray diffraction technique (XRD). The X-ray diffraction results show that the cerium oxide nanoparticles were in cubic structure. The optical absorption spectra of cerium oxide were recorded by UV-VIS spectrophotometer in the range of 320 to 600 nm and photoluminescence spectra in the range of 400-540 nm and have been presented. The energy band gap was determined by Tauc relationship. The crystallite size was determined from Debye-Scherer equation and came out to be 6.4 nm.

  7. A chlorate candle/lithium hydroxide personal breathing apparatus

    NASA Technical Reports Server (NTRS)

    Martin, F. E.

    1972-01-01

    A portable coal mine rescue and survival equipment is reported that consists of a chlorate candle with a lithium hydroxide carbon-dioxide absorbent for oxygen generation, a breathing bag and tubing to conduct breathing to and from the man. A plastic hood incorporating a mouth piece for communication provides also eye protection and prevents inhalation through the nose. Manned testing of a prototype system demonstrated the feasibility of this closed circuit no-maintenance breathing apparatus that provides for good voice communication.

  8. Nanostructures based on alumina hydroxides inhibit tumor growth

    NASA Astrophysics Data System (ADS)

    Fomenko, A. N.; Korovin, M. S.

    2017-09-01

    Nanoparticles and nanostructured materials are one of the most promising developments for cancer therapy. Gold nanoparticles, magnetic nanoparticles based on iron and its oxides and other metal oxides have been widely used in diagnosis and treatment of cancer. Much less research attention has been payed to nanoparticles and nanostructures based on aluminum oxides and hydroxides as materials for cancer diagnosis and treatment. However recent investigations have shown promising results regarding these objects. Here, we review the antitumor results obtained with AlOOH nanoparticles.

  9. Toxicity and Metabolism of Layered Double Hydroxide Intercalated with Levodopa in a Parkinson’s Disease Model

    PubMed Central

    Kura, Aminu Umar; Ain, Nooraini Mohd; Hussein, Mohd Zobir; Fakurazi, Sharida; Hussein-Al-Ali, Samer Hasan

    2014-01-01

    Layered hydroxide nanoparticles are generally biocompatible, and less toxic than most inorganic nanoparticles, making them an acceptable alternative drug delivery system. Due to growing concern over animal welfare and the expense of in vivo experiments both the public and the government are interested to find alternatives to animal testing. The toxicity potential of zinc aluminum layered hydroxide (ZAL) nanocomposite containing anti-Parkinsonian agent may be determined using a PC 12 cell model. ZAL nanocomposite demonstrated a decreased cytotoxic effect when compared to levodopa on PC12 cells with more than 80% cell viability at 100 μg/mL compared to less than 20% cell viability in a direct levodopa exposure. Neither levodopa-loaded nanocomposite nor the un-intercalated nanocomposite disturbed the cytoskeletal structure of the neurogenic cells at their IC50 concentration. Levodopa metabolite (HVA) released from the nanocomposite demonstrated the slow sustained and controlled release character of layered hydroxide nanoparticles unlike the burst uptake and release system shown with pure levodopa treatment. PMID:24722565

  10. A role for calcium hydroxide and dolomite in water: acceleration of the reaction under ultraviolet light.

    PubMed

    Nagase, Hiroyasu; Tsujino, Hidekazu; Kurihara, Daisuke; Saito, Hiroshi; Kawase, Masaya

    2014-04-01

    Organic environmental pollutants are now being detected with remarkably high frequency in the aquatic environment. Photodegradation by ultraviolet light is sometimes used as a method for removing organic chemicals from water; however, this method is relatively inefficient because of the low degradation rates involved, and more efficient methods are under development. Here we show that the removal of various organic pollutants can be assisted by calcined dolomite in aqueous solution under irradiation with ultraviolet light. It was possible to achieve substantial removal of bisphenol A, chlorophenols, alkylphenols, 1-naphthol and 17β-estradiol. The major component of dolomite responsible for the removal was calcium hydroxide. Our results demonstrate that the use of calcium hydroxide with ultraviolet light irradiation can be a very effective method of rapidly removing organic environmental pollutants from water. This is a new role for calcium hydroxide and dolomite in water treatment. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Iron ion and iron hydroxide adsorption to charge-neutral phosphatidylcholine templates

    DOE PAGES

    Wang, Wenjie; Zhang, Honghu; Feng, Shuren; ...

    2016-07-13

    Surface-sensitive X-ray scattering and spectroscopy techniques reveal significant adsorption of iron ions and iron-hydroxide (Fe(III)) complexes to a charge-neutral zwitterionic template of phosphatidylcholine (PC). The PC template is formed by a Langmuir monolayer of dipalmitoyl-PC (DPPC) that is spread on the surface of 2 to 40 μM FeCl 3 solutions at physiological levels of KCl (100 mM). At 40 μM of Fe(III) as many as ~3 iron atoms are associated with each PC group. Grazing incidence X-ray diffraction measurements indicate a significant disruption in the in-plane ordering of DPPC molecules upon iron adsorption. The binding of iron-hydroxide complexes to amore » neutral PC surface is yet another example of nonelectrostatic, presumably covalent bonding to a charge-neutral organic template. Furthermore, the strong binding and the disruption of in-plane lipid structure has biological implications on the integrity of PC-derived lipid membranes, including those based on sphingomyelin.« less

  12. Intercalation and controlled release properties of vitamin C intercalated layered double hydroxide

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gao, Xiaorui, E-mail: gxr_1320@sina.com; School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189; Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA

    Two drug-inorganic composites involving vitamin C (VC) intercalated in Mg–Al and Mg–Fe layered double hydroxides (LDHs) have been synthesized by the calcination–rehydration (reconstruction) method. Powder X-ray diffraction (XRD), Fourier transform infrared (FTIR), and UV–vis absorption spectroscopy indicate a successful intercalation of VC into the interlayer galleries of the LDH host. Studies of VC release from the LDHs in deionised water and in aqueous CO{sub 3}{sup 2−} solutions imply that Mg{sub 3}Al–VC LDH is a better controlled release system than Mg{sub 3}Fe–VC LDH. Analysis of the release profiles using a number of kinetic models suggests a solution-dependent release mechanism, and amore » diffusion-controlled deintercalation mechanism in deionised water, but an ion exchange process in CO{sub 3}{sup 2−} solution. - Graphical abstract: Vitamin C anions have been intercalated in the interlayer space of layered double hydroxide and released in CO{sub 3}{sup 2−} solution and deionised water. - Highlights: • Vitamin C intercalated Mg–Al and Mg–Fe layered double hydroxides were prepared. • Release property of vitamin C in aqueous CO{sub 3}{sup 2−} solution is better. • Avrami-Erofe’ev and first-order models provide better fit for release results. • Diffusion-controlled and ion exchange processes occur in deionised water. • An ion exchange process occurs in CO{sub 3}{sup 2−} solution.« less

  13. Three-dimensionally networked graphene hydroxide with giant pores and its application in supercapacitors

    PubMed Central

    Lee, Dongwook; Seo, Jiwon

    2014-01-01

    The three-dimensionally networked and layered structure of graphene hydroxide (GH) was investigated. After lengthy immersion in a NaOH solution, most of the epoxy groups in the graphene oxide were destroyed, and more hydroxyl groups were generated, transforming the graphene oxide into graphene hydroxide. Additionally, benzoic acid groups were formed, and the ether groups link the neighboring layers, creating a near-3D structure in the GH. To utilize these unique structural features, electrodes with large pores for use in supercapacitors were fabricated using thermal reduction in vacuum. The reduced GH maintained its layered structure and developed a lot of large of pores between/inside the layers. The GH electrodes exhibited high gravimetric as well as high volumetric capacitance. PMID:25492227

  14. Three-dimensionally networked graphene hydroxide with giant pores and its application in supercapacitors

    NASA Astrophysics Data System (ADS)

    Lee, Dongwook; Seo, Jiwon

    2014-12-01

    The three-dimensionally networked and layered structure of graphene hydroxide (GH) was investigated. After lengthy immersion in a NaOH solution, most of the epoxy groups in the graphene oxide were destroyed, and more hydroxyl groups were generated, transforming the graphene oxide into graphene hydroxide. Additionally, benzoic acid groups were formed, and the ether groups link the neighboring layers, creating a near-3D structure in the GH. To utilize these unique structural features, electrodes with large pores for use in supercapacitors were fabricated using thermal reduction in vacuum. The reduced GH maintained its layered structure and developed a lot of large of pores between/inside the layers. The GH electrodes exhibited high gravimetric as well as high volumetric capacitance.

  15. Three-dimensionally networked graphene hydroxide with giant pores and its application in supercapacitors.

    PubMed

    Lee, Dongwook; Seo, Jiwon

    2014-12-10

    The three-dimensionally networked and layered structure of graphene hydroxide (GH) was investigated. After lengthy immersion in a NaOH solution, most of the epoxy groups in the graphene oxide were destroyed, and more hydroxyl groups were generated, transforming the graphene oxide into graphene hydroxide. Additionally, benzoic acid groups were formed, and the ether groups link the neighboring layers, creating a near-3D structure in the GH. To utilize these unique structural features, electrodes with large pores for use in supercapacitors were fabricated using thermal reduction in vacuum. The reduced GH maintained its layered structure and developed a lot of large of pores between/inside the layers. The GH electrodes exhibited high gravimetric as well as high volumetric capacitance.

  16. Role of Water in Proton-Hydroxide Conductance Across Membranes

    DTIC Science & Technology

    1988-06-28

    a~a,:v %~ ’ diffusion , rather than hopping along water wires, and there should be little or no deuterium effect. References Bangham , A.D...CONTRACT TITLE: Role of water in proton-hydroxide conductance across model and biological membranes. START DATE: October 1, 1987 RESEARCH OBJECTIVE: To...hypothesis of Bangham and Mason (1980) who suggested that general anesthetics might introduce defects into bilayers of synaptic vesicle membranes which lead

  17. Intercalation of anionic organic ultraviolet ray absorbers into layered zinc hydroxide nitrate.

    PubMed

    Cursino, Ana Cristina Trindade; Gardolinski, José Eduardo Ferreira da Costa; Wypych, Fernando

    2010-07-01

    Layered zinc hydroxide nitrate (ZHN) was synthesized and nitrate ions were topotactically exchanged with three different anionic species of commercial organic ultraviolet (UV) ray absorbers: 2-mercaptobenzoic acid, 2-aminobenzoic acid, and 4-aminobenzoic acid. The exchange reactions were confirmed by X-ray powder diffraction (XRPD), Fourier transform infrared spectroscopy (FTIR), ultraviolet visible (UV-Vis) spectroscopy, and thermal analysis (thermogravimetry, TGA, and differential thermal analysis, DTA). In all the anionic exchanged products, evidence of grafting of the organic species onto the inorganic matrix was obtained. In general, after intercalation/grafting, the UV absorption ability was improved in relation to the use of the parent organic material, showing that layered hydroxide salts (LHS) can be good alternative matrixes for the immobilization of organic species with UV-blocking properties in cosmetic products. Copyright 2010 Elsevier Inc. All rights reserved.

  18. Phillips and Acaba with Lithium Hydroxide (LiOH) canisters on Middeck (MDDK)

    NASA Image and Video Library

    2009-03-19

    S119-E-006645 (19 March 2009) --- Astronauts John Phillips (left) and Joseph Acaba, both STS-119 mission specialists, work with the lithium hydroxide (LiOH) canisters beneath Space Shuttle Discovery's middeck while docked with the International Space Station.

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

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Taşköprü, T., E-mail: ttaskopru@anadolu.edu.tr; Department of Physics, Çankırı Karatekin University, Çankırı 18100; Zor, M.

    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 depositedmore » 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.« less

  20. Comparative evaluation of effectiveness of sodium dichloroisocyanurate and calcium hydroxide against Candida albicans.

    PubMed

    Kurian, Jacob; Bolla, Nagesh; Damaraju, Bhargavi

    2012-09-01

    Candida albicans is the most commonly isolated fungi from the oral cavity. It is the most infective to various intracanal medicaments and is considered as invasive yeast. Sodium dichloroisocyanurate (NaDCC) which is used as a disinfectant and as a biocide in treating potable water has similar action to that of sodium hypochlorite against microbes. The aim of the present study is to compare the effectiveness of calcium hydroxide and NaDCC against Candida albicans. After obtaining the stock cultures of Candida, the isolates were divided into six groups which were exposed to different concentrations of NaDCC and calcium hydroxide Ca(OH)₂. Group 1 consisted of the isolates which were subdivided into three groups, subjected to three different concentrations of NaDCC. Group 2 also consisted of three subgroups exposed to three different concentrations of Ca(OH)₂. Group three consisted of three subgroups which were exposed to three different concentrations of combinations of both NaDCC and Ca(OH)₂. The results of the present study show that calcium hydroxide was totally ineffective at all concentrations and NaDCC was effective and also the combination of both was shown to be effective. NaDCC alone was effective at all concentrations and the combination with Ca(OH)₂ was found to be less effective. Ca(OH)₂ was totally ineffective.

  1. Efficient UV-emitting X-ray phosphors: octahedral Zr(PO 4) 6 luminescence centers in potassium hafnium-zirconium phosphates K 2Hf 1- xZr x(PO 4) 2 and KHf 2(1- x) Zr 2 x(PO 4) 3

    NASA Astrophysics Data System (ADS)

    Torardi, C. C.; Miao, C. R.; Li, J.

    2003-02-01

    Potassium hafnium-zirconium phosphates, K 2Hf 1- xZr x(PO 4) 2 and KHf 2(1- x) Zr 2 x(PO 4) 3, are broad-band UV-emitting phosphors. At room temperature, they have emission peak maxima at approximately 322 and 305 nm, respectively, under 30 kV peak molybdenum X-ray excitation. Both phosphors demonstrate luminescence efficiencies that make them up to ˜60% as bright as commercially available CaWO 4 Hi-Plus. The solid-state and flux synthesis conditions, and X-ray excited UV luminescence of these two phosphors are discussed. Even though the two compounds have different atomic structures, they contain zirconium in the same active luminescence environment as that found in highly efficient UV-emitting BaHf 1- xZr x(PO 4) 2. All the three materials have hafnium and zirconium in octahedral coordination via oxygen-atom corner sharing with six separate PO 4 tetrahedra. This octahedral Zr(PO 4) 6 moiety appears to be an important structural element for efficient X-ray excited luminescence, as are the edge-sharing octahedral TaO 6 chains for tantalate emission.

  2. Exploring Alkaline Stable Organic Cations for Polymer Hydroxide Exchange Membranes

    DTIC Science & Technology

    2015-04-29

    1   1.1.2   Proton exchange membrane fuel cells ( PEMFCs ) ......................... 3   1.1.3   Alkaline fuel cells (AFCs...160   xi LIST OF FIGURES Figure 1.1:   Schematic diagram of a PEMFC ...according to the type of electrolyte they use. Nowadays, there are six major types of fuel cells: proton-exchange membrane fuel cells ( PEMFCs ), hydroxide

  3. The mechanism of thermal-gradient mass transfer in the sodium hydroxide-nickel system

    NASA Technical Reports Server (NTRS)

    May, Charles E

    1958-01-01

    "Thermal-gradient mass transfer" was investigated in the molten sodium hydroxide-nickel system. Possible mechanisms (physical, electrochemical, and chemical) are discussed in terms of experimental and theoretical evidence. Experimental details are included in appendixes.

  4. Niobium powder synthesized by calciothermic reduction of niobium hydroxide for use in capacitors

    NASA Astrophysics Data System (ADS)

    Baba, Masahiko; Kikuchi, Tatsuya; Suzuki, Ryosuke O.

    2015-03-01

    Metallic niobium powder was produced for applications in electric capacitors via calciothermic reduction of niobium hydroxide in molten CaCl2. Sub-micrometer spherical metallic particles with coral-like morphologies reflected the particle size of the starting oxide powder. A fine powder was obtained from the mixtures of niobium hydroxide and CaO or Ca(OH)2, respectively. Sintered pellets of the metallic powder showed a higher capacitance (CV) than those of the simply reduced powder without pre-treatment, because the shrinkage during sintering was smaller. The CV was as large as that of commercially sintered pellets for tantalum capacitors. Therefore, this niobium powder would act as a higher-voltage capacitor by applying chemical anodic treatment at higher voltages, and lower oxygen content in the reduced power could realize a lower leak current.

  5. Calcium Hydroxide-induced Proliferation, Migration, Osteogenic Differentiation, and Mineralization via the Mitogen-activated Protein Kinase Pathway in Human Dental Pulp Stem Cells.

    PubMed

    Chen, Luoping; Zheng, Lisha; Jiang, Jingyi; Gui, Jinpeng; Zhang, Lingyu; Huang, Yan; Chen, Xiaofang; Ji, Jing; Fan, Yubo

    2016-09-01

    Calcium hydroxide has been extensively used as the gold standard for direct pulp capping in clinical dentistry. It induces proliferation, migration, and mineralization in dental pulp stem cells (DPSCs), but the underlying mechanisms are still unclear. The aim of this study was to investigate the role of the mitogen-activated protein (MAP) kinase pathway in calcium hydroxide-induced proliferation, migration, osteogenic differentiation, and mineralization in human DPSCs. Human DPSCs between passages 3 and 6 were used. DPSCs were preincubated with inhibitors of MAP kinases and cultured with calcium hydroxide. The phosphorylated MAP kinases were detected by Western blot analysis. Cell viability was analyzed via the methylthiazol tetrazolium assay. Cell migration was estimated using the wound healing assay. Alkaline phosphatase (ALP) expression was analyzed using the ALP staining assay. Mineralization was studied by alizarin red staining analysis. Calcium hydroxide significantly promoted the phosphorylation of the c-Jun N-terminal kinase (JNK), p38, and extracellular signal-regulated kinase. The inhibition of JNK and p38 signaling abolished calcium hydroxide-induced proliferation of DPSCs. The inhibition of JNK, p38, and extracellular signal-regulated kinase signaling suppressed the migration, ALP expression, and mineralization of DPSCs. Our study showed that the MAP kinase pathway was involved in calcium hydroxide-induced proliferation, migration, osteogenic differentiation, and mineralization in human DPSCs. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  6. Photoinitiated Bottom-Up Click Synthesis of Ion-Containing Networks as Hydroxide Exchange Membranes

    NASA Astrophysics Data System (ADS)

    Tibbits, Andrew Charles

    Fuel cells are energy conversion devices which directly convert chemical energy into electrical energy and environmentally friendly byproducts (i.e., water) with potential versatility for transportation and portable applications. Hydroxide exchange membrane fuel cells (HEMFCs) have the potential to decrease the overall fuel cell cost through the utilization of non-precious metal catalysts such as nickel and silver as opposed to platinum which is used by the current standard technology, proton exchange membrane fuel cells (PEMFCs). However, substantial improvements in thermal and alkaline stability, hydroxide conductivity, mechanical flexibility, and processing are needed to create a competitive membrane for HEMFC applications. Regardless of the type of membrane, the high water uptake that is typically associated with increased ionic conductivity is problematic and can result in the dissolution of the membrane during fuel cell operation. Covalent crosslinking of the membrane is an approach which has been effectively applied to reduce water uptake without a significant compromise of the hydroxide conductivity. The synthesis and processing of membrane materials is vastly simplified by using click polymerization schemes. Click chemistry is a collection of organic chemical reactions that are rapid, selective, and high yielding. One of the most versatile and facile click reactions is the thiol-ene reaction, which is the radical-mediated addition reaction between a thiol (an -SH group) and an 'ene' (an electron rich vinyl group, C=C) in the presence of a photoinitiator and light. The click attributes of the thiol-ene reaction enables potential of "bottom-up" design of ion-containing polymers via a single step photoinitiated crosslinking reaction with precise control over structure and physicochemical properties not only for fuel cell membranes but also for a range of other applications including separations, sensors, flexible electronics, and coatings. However, a

  7. Facing-target mid-frequency magnetron reactive sputtered hafnium oxide film: Morphology and electrical properties

    NASA Astrophysics Data System (ADS)

    Zhang, Yu; Xu, Jun; Wang, You-Nian; Choi, Chi Kyu; Zhou, Da-Yu

    2016-03-01

    Amorphous hafnium dioxide (HfO2) film was prepared on Si (100) by facing-target mid-frequency reactive magnetron sputtering under different oxygen/argon gas ratio at room temperature with high purity Hf target. 3D surface profiler results showed that the deposition rates of HfO2 thin film under different O2/Ar gas ratio remain unchanged, indicating that the facing target midfrequency magnetron sputtering system provides effective approach to eliminate target poisoning phenomenon which is generally occurred in reactive sputtering procedure. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) demonstrated that the gradual reduction of oxygen vacancy concentration and the densification of deposited film structure with the increase of oxygen/argon (O2/Ar) gas flow ratio. Atomic force microscopy (AFM) analysis suggested that the surface of the as-deposited HfO2 thin film tends to be smoother, the root-meansquare roughness (RMS) reduced from 0.876 nm to 0.333 nm while O2/Ar gas flow ratio increased from 1/4 to 1/1. Current-Voltage measurements of MOS capacitor based on Au/HfO2/Si structure indicated that the leakage current density of HfO2 thin films decreased by increasing of oxygen partial pressure, which resulted in the variations of pore size and oxygen vacancy concentration in deposited thin films. Based on the above characterization results the leakage current mechanism for all samples was discussed systematically.

  8. METHOD FOR RECOVERING PLUTONIUM VALUES FROM SOLUTION USING A BISMUTH HYDROXIDE CARRIER PRECIPITATE

    DOEpatents

    Faris, B.F.

    1961-04-25

    Carrier precipitation processes for separating plutonium values from aqueous solutions are described. In accordance with the invention a bismuth hydroxide precipitate is formed in the plutonium-containing solution, thereby carrying plutonium values from the solution.

  9. Extraction of starch from hulled and hull-less barley with papain and aqueous sodium hydroxide.

    PubMed

    Sharma, Priyanka; Tejinder, S

    2014-12-01

    Starch was isolated from hulled (VJM 201) and hull-less (BL 134) barley with papain and aqueous sodium hydroxide treatments. For enzyme-assisted extraction, barley was steeped in water containing 0.2 % SO2 + 0.55 % lactic acid at 50° ± 2 °C for 4-5 h. The slurry was mixed with 0.4-2.0 g papain/kg barley and incubated at 50° ± 2 °C for 1-5 h. Aqueous sodium hydroxide (0.01-0.05 M) was added to the finely ground barley meal. The alkaline slurry was incubated at ambient temperature (25° ± 2 °C) for 15-60 min. The starch and grain fractions were isolated by screening and centrifugation. Increases in the time of treatment significantly affected the fiber, centrifugation and non-starch residue losses. Concentration of papain and sodium hydroxide had negligible effect on extraction losses. The enzyme-assisted extraction efficiency of starch was higher (80.7-84.6 %) than the alkaline method (70.9-83.7 %). The hulled barley showed higher extraction efficiency than the hull-less barley. The slurry treated with 0.4 g papain/kg barley for 5 h and 0.03 M sodium hydroxide for 60 min produced maximal yield of starch. Barley starch showed desirably high pasting temperature, water binding capacity and hold viscosity; and low final and setback viscosity compared with the commercial corn starch. The alkaline extracted hull-less barley starch showed exceptionally high peak and hold viscosities.

  10. Energy and structure of bonds in the interaction of organic anions with layered double hydroxide nanosheets: A molecular dynamics study

    NASA Astrophysics Data System (ADS)

    Tsukanov, A. A.; Psakhie, S. G.

    2016-01-01

    The application of hybrid and hierarchical nanomaterials based on layered hydroxides and oxyhydroxides of metals is a swiftly progressing field in biomedicine. Layered double hydroxides (LDH) possess a large specific surface area, significant surface electric charge and biocompatibility. Their physical and structural properties enable them to adsorb various kinds of anionic species and to transport them into cells. However, possible side effects resulting from the interaction of LDH with anions of the intercellular and intracellular medium need to be considered, since such interaction can potentially disrupt ion transport, signaling processes, apoptosis, nutrition and proliferation of living cells. In the present paper molecular dynamics is used to determine the energies of interaction of organic anions (aspartic acid, glutamic acid and bicarbonate) with a fragment of layered double hydroxide Mg/Al-LDH. The average number of hydrogen bonds between the anions and the hydroxide surface and characteristic binding configurations are determined. Possible effects of LDH on the cell resulting from binding of protein fragments and replacement of native intracellular anions with delivered anions are considered.

  11. Morphologies, Preparations and Applications of Layered Double Hydroxide Micro-/Nanostructures

    PubMed Central

    Kuang, Ye; Zhao, Lina; Zhang, Shuai; Zhang, Fazhi; Dong, Mingdong; Xu, Sailong

    2010-01-01

    Layered double hydroxides (LDHs), also well-known as hydrotalcite-like layered clays, have been widely investigated in the fields of catalysts and catalyst support, anion exchanger, electrical and optical functional materials, flame retardants and nanoadditives. This feature article focuses on the progress in micro-/nanostructured LDHs in terms of morphology, and also on the preparations, applications, and perspectives of the LDHs with different morphologies. PMID:28883378

  12. Evaluation of hydroxyl ion diffusion in dentin and injectable forms and a simple powder-water calcium hydroxide paste: an in vitro study.

    PubMed

    Eftekhar, Behrooz; Moghimipour, Eskandar; Eini, Ebrahim; Jafarzadeh, Mansour; Behrooz, Narges

    2014-08-01

    Intra canal medicaments are used to reduce the number of bacteria and reinfection in endodontic procedures. Calcium Hydroxide was introduced to endodontics by Herman as an intracanal antimicrobial agent. The aim of this study was to present an injectable formulation of calcium hydroxide then compare the final pH of this new formulation with Metapaste and evaluate the effect of a mixture of Calcium Hydroxide powder with water on human extracted teeth. A total of 49 extracted human single-canal roots without caries and visible microcracks were included in this study. The teeth were decoronated and length of teeth was measured 1 mm anatomic apex. The canals were prepared using step-back technique. A cavity was created in the middle third of the buccal surface of all roots. The teeth were randomly divided into five groups: Group A (n = 15): In this group the root canals were filled with a mixture of calcium hydroxide powder and distilled water. Group B (n = 15): Included roots that were filled with Metapaste. Group C (n = 15): Root canals of this group were filled with new formulation of calcium hydroxide paste. Group D (negative control, n = 2): Included roots that were filled with a mixture of calcium hydroxide powder and distilled water. Group E (positive control, n = 2): Root canals of this group were filled with a mixture of calcium hydroxide powder and distilled water. Each tooth was immersed in a separate closed container with 4 mL saline for 2 weeks, pH of liquids were measured with an electrical pH meter after 7 and 14 days. The SPSS software (version 13) was used for data analysis. Analysis of variance (ANOVA) and Tukey tests were used for the statistical evaluation of results. There was no significant difference at 7th day between the groups (P = 0.17) but at 14th day, a significant difference was observed between the groups (P = 0.04). The new formulation of calcium hydroxide with methylcellulose base has slower ionic dissolution, more durability and

  13. Influence of manganese incorporation on structure, surface and As(III)/As(V) removal capacity of iron oxy-hydroxides

    NASA Astrophysics Data System (ADS)

    Tresintsi, Sofia; Simeonidis, Konstantinos; Mitrakas, Manassis

    2013-04-01

    Iron oxy-hydroxides are well defined As(V) adsorbents dominating in water treatment market. The main drawback of these adsorbents, as well as of all commercial one, is their significantly low adsorption capacity for As(III). A breakthrough for improving As(III) adsorption of iron oxy-hydroxides may come by the MnO2incorporation. However, MnO2 decreases the total arsenic capacity proportionally to its percentage since its efficiency for As(V) is much lower than that of an iron oxy-hydroxide. It is concluded that an ideal adsorbent capable for high and simultaneous As(III) and As(V) removal should be consisted of a binary Fe(III)-Mn(IV) oxy-hydroxide both efficient for As(III) oxidation, due to Mn(IV) presence, and capture of As(V) due to a high positively surface charge density. This work studies the optimum parameters at the synthesis of single Fe and binary Fe/Mn oxy-hydroxides in a continuous flow kilogram-scale production reactor through the precipitation of FeSO4 in the pH range 3-12, under intense oxidative conditions using H2O2/KMnO4, that maximize arsenic adsorption. The evaluation of their efficiency was based on its As(III) and As(V) adsorption capacity (Q10-index) at equilibrium concentration equal to drinking water regulation limit (Ce= 10 μg/L) in NSF challenge water. The pH of synthesis was found to decisively affect, the structure, surface configuration and Q10-index. As a result, both single Fe and binary Fe/Mn oxy-hydroxides prepared at pH 4, which consist of schwertmannite and Mn(IV)-feroxyhyte respectively, were qualified according to their highest Q10-index of 13±0.5 μg As(V)/ mg for a residual arsenic concentration of 10 μg/L at an equilibrium pH 7. The high surface charge and the activation of an ion-exchange mechanism between SO42- adsorbed in the Stern layer and arsenate ions were found to significantly contribute to the increased adsorption capacity. The Q10-index for As(III) of Fe/Mn adsorbent at equilibrium pH 7 was 6.7 μg/mg, which

  14. Accidental contamination of a German town's drinking water with sodium hydroxide.

    PubMed

    Lendowski, Luba; Färber, Harald; Holy, Andreas; Darius, Anke; Ehrich, Bernd; Wippermann, Christine; Küfner, Bernd; Exner, Martin

    2015-05-01

    Case report of a very serious drinking water incident putting up to 50,000 inhabitants of a town near Bonn in North Rhine-Westphalia, Germany at risk. A concentrated solution of highly alkaline water by sodium hydroxide was accidentally washed into the town's drinking water at a pumping station and increased the pH-value of the water to 12. Residents who came into contact with the contaminated water immediately had a toxic reaction. The incident was detected by complaints from customers and after that was stopped within several hours. The pipes were flushed and the customers were warned not to use the water till the all clear. After this immediate management there was an investigation and the cause of the incident was detected as an accidental release of accumulated sodium hydroxide (NaOH) solution. The lack of a network alarm system and the automatic cut-off mechanisms as deficiencies in the design of the station were rectified by the water company immediately after the incident. Copyright © 2015 Elsevier GmbH. All rights reserved.

  15. Synthesis of (cinnamate-zinc layered hydroxide) intercalation compound for sunscreen application

    PubMed Central

    2013-01-01

    Background Zinc layered hydroxide (ZLH) intercalated with cinnamate, an anionic form of cinnamic acid (CA), an efficient UVA and UVB absorber, have been synthesized by direct method using zinc oxide (ZnO) and cinnamic acid as the precursor. Results The resulting obtained intercalation compound, ZCA, showed a basal spacing of 23.9 Å as a result of cinnamate intercalated in a bilayer arrangement between the interlayer spaces of ZLH with estimated percentage loading of cinnamate of about 40.4 % w/w. The UV–vis absorption spectrum of the intercalation compound showed excellent UVA and UVB absorption ability. Retention of cinnamate in ZLH interlayers was tested against media usually came across with sunscreen usage to show low release over an extended period of time. MTT assay of the intercalation compound on human dermal fibroblast (HDF) cells showed cytotoxicity of ZCA to be concentration dependent and is overall less toxic than its precursor, ZnO. Conclusions (Cinnamate-zinc layered hydroxide) intercalation compound is suitable to be used as a safe and effective sunscreen with long UV protection effect. PMID:23383738

  16. What can hafnium isotope ratios arrays tell us about orogenic processes? An insight into geodynamic processes operating in the Alpine/Mediterranean region

    NASA Astrophysics Data System (ADS)

    Henderson, B.; Murphy, J.; Collins, W. J.; Hand, M. P.

    2013-12-01

    Over the last decade, technological advances in laser-ablation sampling techniques have resulted in an increase in the number of combined U-Pb-Hf zircon isotope studies used to investigate crustal evolution on a local, regional and global scale. Hafnium isotope arrays over large time scales (>500 myr) have been interpreted to track evolving plate tectonic configurations, and the geological outputs associated with changing plate boundaries. We use the Alpine-Mediterranean region as an example of how hafnium isotope arrays record the geodynamic processes associated with the complex geological evolution of a region. The geology of Alpine-Mediterranean region preserves a complex, semi-continuous tectonic history that extends from the Neoproterozoic to the present day. Major components of the Variscan and Alpine orogens are microcontinental ribbons derived from the northern Gondwanan margin, which were transferred to the Eurasian plate during the opening and closing of the Rheic and Paleo-Tethys Oceans. Convergence of the Eurasian and African plates commenced in the Mid-Late Cretaceous, following the destruction of the Alpine-Tethys Ocean during the terminal breakup of Pangea. In general, convergence occurred slowly and is characterised by northward accretion of Gondwanan fragments, interspersed with subduction of African lithosphere and intermittent roll-back events. A consequence of this geodynamic scenario was periods of granite-dominated magmatism in an arc-backarc setting. New Hf isotope data from the peri-Gondwanan terranes (Iberia, Meguma and Avalonia) and a compilation of existing Phanerozoic data from the Alpine-Mediterranean region, indicate ~500 myr (Cambrian-Recent) of reworking of peri-Gondwanan crust. The eHf array follows a typical crustal evolution pattern (Lu/Hf=0.015) and is considered to reflect reworking of juvenile peri-Gondwanan (Neoproterozoic) crust variably mixed with an older (~1.8-2.0 Ga) source component, probably Eburnian crust from the West

  17. The energy landscape of glassy dynamics on the amorphous hafnium diboride surface

    NASA Astrophysics Data System (ADS)

    Nguyen, Duc; Mallek, Justin; Cloud, Andrew N.; Abelson, John R.; Girolami, Gregory S.; Lyding, Joseph; Gruebele, Martin

    2014-11-01

    Direct visualization of the dynamics of structural glasses and amorphous solids on the sub-nanometer scale provides rich information unavailable from bulk or conventional single molecule techniques. We study the surface of hafnium diboride, a conductive ultrahigh temperature ceramic material that can be grown in amorphous films. Our scanning tunneling movies have a second-to-hour dynamic range and single-point current measurements extend that to the millisecond-to-minute time scale. On the a-HfB2 glass surface, two-state hopping of 1-2 nm diameter cooperatively rearranging regions or "clusters" occurs from sub-milliseconds to hours. We characterize individual clusters in detail through high-resolution (<0.5 nm) imaging, scanning tunneling spectroscopy and voltage modulation, ruling out individual atoms, diffusing adsorbates, or pinned charges as the origin of the observed two-state hopping. Smaller clusters are more likely to hop, larger ones are more likely to be immobile. HfB2 has a very high bulk glass transition temperature Tg, and we observe no three-state hopping or sequential two-state hopping previously seen on lower Tg glass surfaces. The electronic density of states of clusters does not change when they hop up or down, allowing us to calibrate an accurate relative z-axis scale. By directly measuring and histogramming single cluster vertical displacements, we can reconstruct the local free energy landscape of individual clusters, complete with activation barrier height, a reaction coordinate in nanometers, and the shape of the free energy landscape basins between which hopping occurs. The experimental images are consistent with the compact shape of α-relaxors predicted by random first order transition theory, whereas the rapid hopping rate, even taking less confined motion at the surface into account, is consistent with β-relaxations. We make a proposal of how "mixed" features can show up in surface dynamics of glasses.

  18. The effect of retreatment procedure on the pH changes at the surface of root dentin using two different calcium hydroxide pastes.

    PubMed

    Kazemipoor, Maryam; Tabrizizadeh, Mehdi; Dastani, Milad; Hakimian, Roqayeh

    2012-10-01

    To compare pH changes at the cervical, middle and apical surfaces of root dentin in retreated and non- retreated teeth, after canal obturation with two different calcium hydroxide pastes. After instrumentation of 55 extracted teeth, three cavities with 0.75 mm depth and 1.5 mm in diameter were drilled at buccal root surface. The teeth were randomly divided into five groups. Canals in the first two groups were filled with either mixture of calcium hydroxide and saline solution and calcium hydroxide and 2% chlorhexidine (CHX). In the third and fourth groups canals were first obturated with gutta-percha and AH26 sealer, and then materials were removed. After 2 days canals were filled with two different calcium hydroxide pastes similar to the first and the second groups. The pH was measured in the prepared cavities at 1, 3, 7 and 14 days. In the non-retreated groups, pH at the surface of the roots was significantly higher in comparison to the retreated ones (P value < 0.001). pH values were significantly higher in the non-retreated teeth filling with calcium hydroxide and saline solution (P value < 0.001). Regarding to the little pH changes at the surface of dentin in retreated teeth, the hydroxyl ions cannot penetrate into the dentinal tubules. Thus, to achieve higher pH at the root surface in retreated teeth, it is clinically advisable to remove more dentin from the inner walls and to use normal saline as a vehicle for calcium hydroxide rather than acidic pH materials.

  19. Stabilization of tetanus toxoid formulation containing aluminium hydroxide adjuvant against freeze-thawing.

    PubMed

    Solanki, Vipul A; Jain, Nishant K; Roy, Ipsita

    2011-07-29

    Exposure to subzero temperature leads to loss of vaccine potency. This can happen due to degradation of adjuvant surface and/or inactivation of the antigen. When adsorbed on aluminium hydroxide and subjected to freeze-thawing, tetanus toxoid was desorbed from the gel matrix and the preparation was found to lose its antigenicity. Analyses showed that the gel particles were denatured after freezing. When freeze-thawing was carried out in the presence of glucose, sorbitol and arginine, the degradation of gel particles was inhibited. A higher fraction of the protein could be retained on the gel. However, the antigenicity of these preparations was quite low. In the presence of trehalose, the protein could be partially retained on aluminium hydroxide. Being a cryoprotectant, trehalose was also able to inhibit the freezing-induced denaturation of tetanus toxoid, which resulted in retention of antigenicity of the adjuvanted toxoid. Copyright © 2011 Elsevier B.V. All rights reserved.

  20. Evaluation of mineral trioxide aggregate (MTA) versus calcium hydroxide cement (Dycal(®) ) in the formation of a dentine bridge: a randomised controlled trial.

    PubMed

    Leye Benoist, Fatou; Gaye Ndiaye, Fatou; Kane, Abdoul Wakhabe; Benoist, Henri Michel; Farge, Pierre

    2012-02-01

    To assess the effectiveness of mineral trioxide aggregate (MTA) used as an indirect pulp-capping material in human molar and premolar teeth. We conducted a clinical evaluation of 60 teeth, which underwent an indirect pulp-capping procedure with either MTA or calcium hydroxide cement (Dycal(®) ). Calcium hydroxide was compared with MTA and the thickness of the newly formed dentine was measured at regular time intervals. The follow-up was at 3 and 6 months, and dentine formation was monitored by radiological measurements on digitised images using Mesurim Pro(®) software. At 3 months, the clinical success rates of MTA and calcium hydroxide were 93% and 73%, respectively (P = 0.02). At 6 months, the success rate was 89.6% with MTA, and remained steady at 73% with calcium hydroxide (P = 0.63). The mean initial residual dentine thickness was 0.23 mm, and increased by 0.121 mm with MTA and by 0.136 mm with calcium hydroxide at 3 months. At 6 months, there was an increase of 0.235 mm with MTA and of 0.221 mm with calcium hydroxide.   A higher success rate was observed in the MTA group relative to the Dycal(®) group after 3 months, which was statistically significant. After 6 months, no statistically significant difference was found in the dentine thickness between the two groups. Additional histological investigations are needed to support these findings. © 2012 FDI World Dental Federation.

  1. Method for locating metallic nitride inclusions in metallic alloy ingots

    DOEpatents

    White, Jack C.; Traut, Davis E.; Oden, Laurance L.; Schmitt, Roman A.

    1992-01-01

    A method of determining the location and history of metallic nitride and/or oxynitride inclusions in metallic melts. The method includes the steps of labeling metallic nitride and/or oxynitride inclusions by making a coreduced metallic-hafnium sponge from a mixture of hafnium chloride and the chloride of a metal, reducing the mixed chlorides with magnesium, nitriding the hafnium-labeled metallic-hafnium sponge, and seeding the sponge to be melted with hafnium-labeled nitride inclusions. The ingots are neutron activated and the hafnium is located by radiometric means. Hafnium possesses exactly the proper metallurgical and radiochemical properties for this use.

  2. Visible-light-enhanced interactions of hydrogen sulfide with composites of zinc (oxy)hydroxide with graphite oxide and graphene.

    PubMed

    Seredych, Mykola; Mabayoje, Oluwaniyi; Bandosz, Teresa J

    2012-01-17

    Composites of zinc(oxy)hydroxide-graphite oxide and of zinc(oxy)hydroxide-graphene were used as adsorbents of hydrogen sulfide under ambient conditions. The initial and exhausted samples were characterized by XRD, FTIR, potentiometric titration, EDX, thermal analysis, and nitrogen adsorption. An increase in the amount of H(2)S adsorbed/oxidized on their surfaces in comparison with that of pure Zn(OH)(2) is linked to the structure of the composite, the relative number of terminal hydroxyls, and the kind of graphene-based phase used. Although terminal groups are activated by a photochemical process, the graphite oxide component owing to the chemical bonds with the zinc(oxy)hydroxide phase and conductive properties helps in electron transfer, leading to more efficient oxygen activation via the formation of superoxide ions. Elemental sulfur, zinc sulfide, sulfite, and sulfate are formed on the surface. The formation of sulfur compounds on the surface of zinc(oxy)hydroxide during the course of the breakthrough experiments and thus Zn(OH)(2)-ZnS heterojunctions can also contribute to the increased surface activity of our materials. The results show the superiority of graphite oxide in the formation of composites owing to its active surface chemistry and the possibility of interface bond formation, leading to an increase in the number of electron-transfer reactions. © 2011 American Chemical Society

  3. Synthesis and structure of [Na11(OtBu)10(OH)]: 1H NMR shift of a hydroxide ion encapsulated in a 21-vertex alcoholate cage.

    PubMed

    Geier, Jens; Grützmacher, Hansjörg

    2003-12-07

    [Na11(OtBu)10(OH)], a hydroxide enclosing 21-vertex cage compound, was found to crystallize from mixtures of sodium tert.butanolate with sodium hydroxide. Its structure can be derived from the known (NaOtBu)6-hexaprismane by replacing one butanolate unit with OH- and capping the latter with five additional units of NaOtBu. The hydroxide shows a signal at -3.21 ppm in the 1H NMR spectrum.

  4. Controlling electrodeposited ultrathin amorphous Fe hydroxides film on V-doped nickel sulfide nanowires as efficient electrocatalyst for water oxidation

    NASA Astrophysics Data System (ADS)

    Shang, Xiao; Yan, Kai-Li; Lu, Shan-Shan; Dong, Bin; Gao, Wen-Kun; Chi, Jing-Qi; Liu, Zi-Zhang; Chai, Yong-Ming; Liu, Chen-Guang

    2017-09-01

    Developing cost-effective electrocatalysts with both high activity and stability remains challenging for oxygen evolution reaction (OER) in water electrolysis. Herein, based on V-doped nickel sulfide nanowire on nickel foam (NiVS/NF), we further conduct controllable electrodeposition of Fe hydroxides film on NiVS/NF (eFe/NiVS/NF) to further improve OER performance and stability. For comparison, ultrafast chemical deposition of Fe hydroxides on NiVS/NF (uFe/NiVS/NF) is also utilized. V-doping of NiVS/NF may introduce more active sites for OER, and nanowire structure can expose abundant active sites and facilitate mass transport. Both of the two depositions generate amorphous Fe hydroxides film covering on the surface of nanowires and lead to enhanced OER activities. Furthermore, electrodeposition strategy realizes uniform Fe hydroxides film on eFe/NiVS/NF confirmed by superior OER activity of eFe/NiVS/NF than uFe/NiVS/NF with relatively enhanced stability. The OER activity of eFe/NiVS/NF depends on various electrodepositon time, and the optimal time (15 s) is obtained with maximum OER activity. Therefore, the controllable electrodeposition of Fe may provide an efficient and simple strategy to enhance the OER properties of electrocatalysts.

  5. Electrochemical formation of hydroxide for enhancing carbon dioxide and acid gas uptake by a solution

    DOEpatents

    Rau, Gregory Hudson [Castro Valley, CA

    2012-05-15

    A system is described for forming metal hydroxide from a metal carbonate utilizing a water electrolysis cell having an acid-producing anode and a hydroxyl-producing cathode immersed in a water solution of sufficient ionic content to allow an electric current to pass between the hydroxyl-producing cathode and the acid-producing anode. A metal carbonate, in particular water-insoluble calcium carbonate or magnesium carbonate, is placed in close proximity to the acid-producing anode. A direct current electrical voltage is provided across the acid-producing anode and the hydroxyl-producing cathode sufficient to generate acid at the acid-producing anode and hydroxyl ions at the hydroxyl-producing cathode. The acid dissolves at least part of the metal carbonate into metal and carbonate ions allowing the metal ions to travel toward the hydroxyl-producing cathode and to combine with the hydroxyl ions to form the metal hydroxide. The carbonate ions travel toward the acid-producing anode and form carbonic acid and/or water and carbon dioxide. Among other uses, the metal hydroxide formed can be employed to absorb acid gases such as carbon dioxide from a gas mixture. The invention can also generate hydrogen and oxidative gases such as oxygen or chlorine.

  6. Ferric hydroxide supported gold subnano clusters or quantum dots: enhanced catalytic performance in chemoselective hydrogenation.

    PubMed

    Liu, Lequan; Qiao, Botao; Ma, Yubo; Zhang, Juan; Deng, Youquan

    2008-05-21

    An attempt to prepare ferric hydroxide supported Au subnano clusters via modified co-precipitation without any calcination was made. High resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) have been employed to study the structure and chemical states of these catalysts. No Au species could be observed in the HRTEM image nor from the XRD pattern, suggesting that the sizes of the Au species in and on the ferric hydroxide support were less than or around 1 nm. Chemoselective hydrogenation of aromatic nitro compounds and alpha,beta-unsaturated aldehydes was selected as a probe reaction to examine the catalytic properties of this catalyst. Under the same reaction conditions, such as 100 degrees C and 1 MPa H2 in the hydrogenation of aromatic nitro compounds, a 96-99% conversion (except for 4-nitrobenzonitrile) with 99% selectivity was obtained over the ferric hydroxide supported Au catalyst, and the TOF values were 2-6 times higher than that of the corresponding ferric oxide supported catalyst with 3-5 nm size Au particles. For further evaluation of this Au catalyst in the hydrogenation of citral and cinnamaldehyde, selectivity towards unsaturated alcohols was 2-20 times higher than that of the corresponding ferric oxide Au catalyst.

  7. Aqueous Ammonia or Ammonium Hydroxide? Identifying a Base as Strong or Weak

    ERIC Educational Resources Information Center

    Sanger, Michael J.; Danner, Matthew

    2010-01-01

    When grocery stores sell solutions of ammonia, they are labeled "ammonia"; however, when the same solution is purchased from chemical supply stores, they are labeled "ammonium hydroxide". The goal of this experiment is for students to determine which name is more appropriate. In this experiment, students use several different experimental methods…

  8. Determination of soluble bromine in an extra-high-pressure mercury discharge lamp by sodium hydroxide decomposition-suppressed ion chromatography.

    PubMed

    Mitsumata, Hiroshi; Mori, Toshio; Maeda, Tatsuo; Kita, Yoshiyuki; Kohatsu, Osamu

    2006-02-01

    We have established a simple method for assaying the quantity of soluble bromine in the discharge tubes of an extra-high-pressure mercury discharge lamp. Each discharge tube is destroyed in 5 ml of 10 mM sodium hydroxide, and the recovered sodium hydroxide solution is analyzed by suppressed-ion chromatography using gradient elution. We have clarified that this method can assay less than 1 microg of soluble bromine in a discharge tube.

  9. Evaluation of the Magnesium Hydroxide Treatment Process for Stabilizing PFP Plutonium/Nitric Acid Solutions

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gerber, Mark A.; Schmidt, Andrew J.; Delegard, Calvin H.

    2000-09-28

    This document summarizes an evaluation of the magnesium hydroxide [Mg(OH)2] process to be used at the Hanford Plutonium Finishing Plant (PFP) for stabilizing plutonium/nitric acid solutions to meet the goal of stabilizing the plutonium in an oxide form suitable for storage under DOE-STD-3013-99. During the treatment process, nitric acid solutions bearing plutonium nitrate are neutralized with Mg(OH)2 in an air sparge reactor. The resulting slurry, containing plutonium hydroxide, is filtered and calcined. The process evaluation included a literature review and extensive laboratory- and bench-scale testing. The testing was conducted using cerium as a surrogate for plutonium to identify and quantifymore » the effects of key processing variables on processing time (primarily neutralization and filtration time) and calcined product properties.« less

  10. The effect of retreatment procedure on the pH changes at the surface of root dentin using two different calcium hydroxide pastes

    PubMed Central

    Kazemipoor, Maryam; Tabrizizadeh, Mehdi; Dastani, Milad; Hakimian, Roqayeh

    2012-01-01

    Aim: To compare pH changes at the cervical, middle and apical surfaces of root dentin in retreated and non- retreated teeth, after canal obturation with two different calcium hydroxide pastes. Materials and Methods: After instrumentation of 55 extracted teeth, three cavities with 0.75 mm depth and 1.5 mm in diameter were drilled at buccal root surface. The teeth were randomly divided into five groups. Canals in the first two groups were filled with either mixture of calcium hydroxide and saline solution and calcium hydroxide and 2% chlorhexidine (CHX). In the third and fourth groups canals were first obturated with gutta-percha and AH26 sealer, and then materials were removed. After 2 days canals were filled with two different calcium hydroxide pastes similar to the first and the second groups. The pH was measured in the prepared cavities at 1, 3, 7 and 14 days. Results: In the non-retreated groups, pH at the surface of the roots was significantly higher in comparison to the retreated ones (P value < 0.001). pH values were significantly higher in the non-retreated teeth filling with calcium hydroxide and saline solution (P value < 0.001). Conclusion: Regarding to the little pH changes at the surface of dentin in retreated teeth, the hydroxyl ions cannot penetrate into the dentinal tubules. Thus, to achieve higher pH at the root surface in retreated teeth, it is clinically advisable to remove more dentin from the inner walls and to use normal saline as a vehicle for calcium hydroxide rather than acidic pH materials. PMID:23112482

  11. Improving the quality of rice straw by urea and calcium hydroxide on rumen ecology, microbial protein synthesis in beef cattle.

    PubMed

    Polyorach, S; Wanapat, M

    2015-06-01

    Four rumen-fistulated beef cattle were randomly assigned to four treatments according to a 4 × 4 Latin square design to study the influence of urea and calcium hydroxide [Ca(OH)2 ] treatment of rice straw to improve the nutritive value of rice straw. Four dietary treatments were as follows: untreated rice straw, 50 g/kg urea-treated rice straw, 20 g/kg urea + 20 g/kg calcium hydroxide-treated rice straw and 30 g/kg urea + 20 g/kg calcium hydroxide-treated rice straw. All animals were kept in individual pens and fed with concentrate at 0.5 g/kg of BW (DM), rice straw was fed ad libitum. The experiment was conducted for four periods, and each period lasted for 21 days. During the first 14 days, DM feed intake measurements were made while during the last 7 days, all cattle were moved to metabolism crates for total faeces and urine collections. The results revealed that 20 g/kg urea + 20 g/kg calcium hydroxide-treated rice straw improved the nutritive value of rice straw, in terms of dry matter intake, digestibility, ruminal volatile fatty acids, population of bacteria and fungi, nitrogen retention and microbial protein synthesis. Based on this study, it could be concluded that using urea plus calcium hydroxide was one alternative method to improve the nutritive value of rice straw, rumen ecology and fermentation and thus a reduction of treatment cost. Journal of Animal Physiology and Animal Nutrition © 2014 Blackwell Verlag GmbH.

  12. ATTENUATION/STABILIZATION OF ARSENIC BY IRON (HYDR)OXIDES IN SOILS/SEDIMENTS: LABORATORY STUDY.

    EPA Science Inventory

    Laboratory studies will be performed to assess the role of naturally occurring soil/sediment iron (hydr)oxides on the attenuation/stabilization of arsenic. Changes in the reversibility of arsenic partitioning will be assessed as a function of aging time using model experimental ...

  13. Mechanistic Studies of Hafnium-Pyridyl Amido-Catalyzed 1-Octene Polymerization and Chain Transfer Using Quench-Labeling Methods.

    PubMed

    Cueny, Eric S; Johnson, Heather C; Anding, Bernie J; Landis, Clark R

    2017-08-30

    Chromophore quench-labeling applied to 1-octene polymerization as catalyzed by hafnium-pyridyl amido precursors enables quantification of the amount of active catalyst and observation of the molecular weight distribution (MWD) of Hf-bound polymers via UV-GPC analysis. Comparison of the UV-detected MWD with the MWD of the "bulk" (all polymers, from RI-GPC analysis) provides important mechanistic information. The time evolution of the dual-detection GPC data, concentration of active catalyst, and monomer consumption suggests optimal activation conditions for the Hf pre-catalyst in the presence of the activator [Ph 3 C][B(C 6 F 5 ) 4 ]. The chromophore quench-labeling agents do not react with the chain-transfer agent ZnEt 2 under the reaction conditions. Thus, Hf-bound polymeryls are selectively labeled in the presence of zinc-polymeryls. Quench-labeling studies in the presence of ZnEt 2 reveal that ZnEt 2 does not influence the rate of propagation at the Hf center, and chain transfer of Hf-bound polymers to ZnEt 2 is fast and quasi-irreversible. The quench-label techniques represent a means to study commercial polymerization catalysts that operate with high efficiency at low catalyst concentrations without the need for specialized equipment.

  14. Removal of Lead Hydroxides Complexes from Solutions Formed in Silver/Gold: Cyanidation Process

    NASA Astrophysics Data System (ADS)

    Parga, José R.; Martinez, Raul Flores; Moreno, Hector; Gomes, Andrew Jewel; Cocke, David L.

    2014-04-01

    The presence of lead hydroxides in "pregnant cyanide solution" decreases the quality of the Dore obtained in the recovery processes of gold and silver, so it is convenient to remove them. The adsorbent capacity of the low cost cow bone powder was investigated for the removal of lead ions from a solution of lead hydroxide complexes at different initial metal ion concentrations (10 to 50 mg/L), and reaction time. Experiments were carried out in batches. The maximum sorption capacity of lead determined by the Langmuir model was found to be 126.58 mg/g, and the separation factor R L was between 0 and 1, indicating a significant affinity of bone for lead. Experimental data follow pseudo-second order kinetics suggesting chemisorption. It is concluded that cow bone powder can be successfully used for the removal of lead ions, and improves the quality of the silver-gold cyanides precipitate.

  15. Effects of ammonium hydroxide on the structure and gas adsorption of nanosized Zr-MOFs (UiO-66).

    PubMed

    Abid, Hussein Rasool; Ang, Ha Ming; Wang, Shaobin

    2012-05-21

    Several zirconium-based metal-organic frameworks (Zr-MOFs) have been synthesized using ammonium hydroxide as an additive in the synthesis process. Their physicochemical properties have been characterized by N(2) adsorption/desorption, XRD, SEM, FTIR, and TGA, and their application in CO(2) adsorption was evaluated. It was found that addition of ammonium hydroxide produced some effects on the structure and adsorption behavior of Zr-MOFs. The pore size and pore volume of Zr-MOFs were enhanced with the additive, however, specific surface area of Zr-MOFs was reduced. Using an ammonium hydroxide additive, the crystal size of Zr-MOF was reduced with increasing amount of the additive. All the samples presented strong thermal stability. Adsorption tests showed that capacity of CO(2) adsorption on the Zr-MOFs under standard conditions was reduced due to decreased micropore fractions. However, modified Zr-MOFs had significantly lower adsorption heat. The adsorption capacity of carbon dioxide was increased at high pressure, reaching 8.63 mmol g(-1) at 987 kPa for Zr-MOF-NH(4)-2.

  16. A practical method for measuring the ion exchange capacity decrease of hydroxide exchange membranes during intrinsic degradation

    NASA Astrophysics Data System (ADS)

    Kreuer, Klaus-Dieter; Jannasch, Patric

    2018-01-01

    In this work we present a practical thermogravimetric method for quantifying the IEC (ion exchange capacity) decrease of hydroxide exchange membranes (HEMs) during intrinsic degradation mainly occurring through nucleophilic attack of the anion exchanging group by hydroxide ions. The method involves measuring weight changes under controlled temperature and relative humidity. These conditions are close to these in a fuel cell, i.e. the measured degradation rate includes all effects originating from the polymeric structure, the consumption of hydroxide ions and the release of water. In particular, this approach involves no added solvents or base, thereby avoiding inaccuracies that may arise in other methods due to the presence of solvents (other than water) or co-ions (such as Na+ or K+). We demonstrate the method by characterizing the decomposition of membranes consisting of poly(2,6-dimethyl-1,4-phenylene oxide) functionalized with trimethyl-pentyl-ammonium side chains. The decomposition rate is found to depend on temperature, relative humidity RH (controlling the hydration number λ) and the total water content (controlled by the actual IEC and RH).

  17. Aluminum Coprecipitates with Fe (hydr)oxides: Does Isomorphous Substitution of Al3plus for Fe3plus in Goethite Occur

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    E Bazilevskaya; D Archibald; M Aryanpour

    2011-12-31

    Iron (hydr)oxides are common in natural environments and typically contain large amounts of impurities, presumably the result of coprecipitation processes. Coprecipitation of Al with Fe (hydr)oxides occurs, for example, during alternating reduction-oxidation cycles that promote dissolution of Fe from Fe-containing phases and its re-precipitation as Fe-Al (hydr)oxides. We used chemical and spectroscopic analyses to study the formation and transformation of Al coprecipitates with Fe (hydr)oxides. In addition, periodic density functional theory (DFT) computations were performed to assess the structural and energetic effects of isolated or clustered Al atoms at 8 and 25 mol% Al substitution in the goethite structure. Coprecipitatesmore » were synthesized by raising the pH of dilute homogeneous solutions containing a range of Fe and Al concentrations (100% Fe to 100% Al) to 5. The formation of ferrihydrite in initial suspensions with {<=}20 mol% Al, and of ferrihydrite and gibbsite in initial suspensions with {>=}25 mol% Al was confirmed by infrared spectroscopic and synchrotron-based X-ray diffraction analyses. While base titrations showed a buffer region that corresponded to the hydrolysis of Fe in initial solutions with {<=}25 mol% Al, all of the Al present in these solutions was retained by the solid phases at pH 5, thus indicating Al coprecipitation with the primary Fe hydroxide precipitate. In contrast, two buffer regions were observed in solutions with 30 mol% Al (at pH {approx}2.25 for Fe{sup 3+} and at pH {approx}4 for Al{sup 3+}), suggesting the formation of Fe and Al (hydr)oxides as two separate phases. The Al content of initial coprecipitates influenced the extent of ferrihydrite transformation and of its transformation products as indicated by the presence of goethite, hematite and/or ferrihydrite in aged suspensions. DFT experiments showed that: (i) optimized unit cell parameters for Al-substituted goethites (8 and 25 Mol% Al) in clustered arrangement (i

  18. Hydroxide precursors to produce nanometric YCrO{sub 3}: Characterization and conductivity analysis

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Durán, A., E-mail: dural@cnyn.unam.mx; Meza F, C.; Arizaga, Gregorio Guadalupe Carbajal, E-mail: gregoriocarbajal@yahoo.com.mx

    2012-06-15

    Highlights: ► Y/Cr mixed hydroxide was precipitated with gaseous ammonia. ► The hydroxide treated at 1373 K formed YCrO{sub 3} crystals with 20 nm diameter. ► Electrical properties were different than those found in other methods of synthesis. ► E{sub act} suggests small-polarons as conduction mechanisms. -- Abstract: A precursor to produce perovskite-type YCrO{sub 3} was precipitated by bubbling gaseous ammonia into an yttrium/chromium salts solution. X-ray diffraction showed that the as-prepared powders were amorphous. Thermal treatment between 1273 and 1373 K, leads to formation of polycrystalline YCrO{sub 3} with crystal sizes around 20 nm. High resolution X-ray photoelectron spectramore » showed uniform chemical environment for yttrium and chromium in the amorphous hydroxide and crystalline YCrO{sub 3}. Shifts between Y 3d{sub 5/2} and Cr 2p{sub 3/2} binding energy suggest redistribution or charge transfer between yttrium and chromium ions in the YCrO{sub 3} structure. The electrical properties of YCrO{sub 3}, whose precursors were precipitated with gaseous ammonia are different than those prepared by combustion synthesis. Electrical conductivity presents a sudden increase at ∼473 K, which is associated to the grain size and morphology of the crystallites. The redistribution of charge between Y(III) and Cr(III) is thermally activated by the hopping of small-polarons, which are characterized by the Arrhenius law as the conductive mechanism.« less

  19. Characteristics of laser produced plasmas of hafnium and tantalum in the 1-7 nm region

    NASA Astrophysics Data System (ADS)

    Li, Bowen; Otsuka, Takamitsu; Sokell, Emma; Dunne, Padraig; O'Sullivan, Gerry; Hara, Hiroyuki; Arai, Goki; Tamura, Toshiki; Ono, Yuichi; Dinh, Thanh-Hung; Higashiguchi, Takeshi

    2017-11-01

    Soft X-ray (SXR) spectra from hafnium and tantalum laser produced plasmas were recorded in the 1-7 nm region using two Nd:YAG lasers with pulse lengths of 170 ps and 10 ns, respectively, operating at a range of power densities. The maximum focused peak power density was 2. 3 × 1014 W cm-2 for 170 ps pulses and 1. 8 × 1012 W cm-2 for 10 ns pulses, respectively. Two intense quasicontinuous intensity bands resulting from n = 4 - n = 4 and n = 4 - n = 5 unresolved transition arrays (UTAs) dominate both sets of experimental spectra. Comparison with calculations performed with the Cowan suite of atomic structure codes as well as consideration of previous experimental and theoretical results aided identification of the most prominent features in the spectra. For the 10 ns spectrum, the highest ion stage that could be identified from the n = 4 - n = 5 arrays were lower than silver-like Hf25+ and Ta26+ (which has a 4 d 104 f ground configuration) indicating that the plasma temperature attained was too low to produce ions with an outermost 4 d subshell, while for the 170 ps plasmas the presence of significantly higher stages was deduced and lines due to 4 d-5 p transitions were clearly evident. Furthermore, we show an enhancement of emission from tantalum using dual laser irradiation, and the effect of pre-pulse durations and delay times between two pulses are demonstrated.

  20. Theoretical investigation on the mechanism and dynamics of oxo exchange of neptunyl(VI) hydroxide in aqueous solution.

    PubMed

    Yang, Xia; Chai, Zhifang; Wang, Dongqi

    2015-03-21

    Four types of reaction mechanisms for the oxo ligand exchange of monomeric and dimeric neptunyl(VI) hydroxide in aqueous solution were explored computationally using density functional theory (DFT) and ab initio classical molecular dynamics. The obtained results were compared with previous studies on the oxo exchange of uranyl hydroxide, as well as with experiments. It is found that the stable T-shaped [NpO3(OH)3](3-) intermediate is a key species for oxo exchange in the proton transfer in mononuclear Path I and binuclear Path IV, similar to the case of uranyl(VI) hydroxide. Path I is thought to be the preferred oxo exchange mechanism for neptunyl(VI) hydroxide in our calculations, due to the lower activation energy (22.7 and 13.1 kcal mol(-1) for ΔG(‡) and ΔH(‡), respectively) of the overall reaction. Path II via a cis-neptunyl structure assisted by a water molecule might be a competitive channel against Path I with a mononuclear mechanism, owing to a rapid dynamical process occurring in Path II. In Path IV with the binuclear mechanism, oxo exchange is accomplished via the interaction between [NpO2(OH)4](2-) and T-shaped [NpO3(OH)3](3-) with a low activation energy for the rate-determining step, however, the overall energy required to fulfill the reaction is slightly higher than that in mononuclear Path I, suggesting a possible binuclear process in the higher energy region. The chemical bonding evolution along the reaction pathways was discussed by using topological methodologies of the electron localization function (ELF).

  1. Efficient drug delivery using SiO2-layered double hydroxide nanocomposites.

    PubMed

    Li, Li; Gu, Zi; Gu, Wenyi; Liu, Jian; Xu, Zhi Ping

    2016-05-15

    MgAl-layered double hydroxide (MgAl-LDH) nanoparticles have great potentials in drug and siRNA delivery. In this work, we used a nanodot-coating strategy to prepare SiO2 dot-coated layered double hydroxide (SiO2@MgAl-LDH) nanocomposites with good dispersibility and controllable size for drug delivery. The optimal SiO2@MgAl-LDH nanocomposite was obtained by adjusting synthetic parameters including the mass ratio of MgAl-LDH to SiO2, the mixing temperature and time. The optimal SiO2@MgAl-LDH nanocomposite was shown to have SiO2 nanodots (10-15nm in diameter) evenly deposited on the surface of MgAl-LDHs (110nm in diameter) with the plate-like morphology and the average hydrodynamic diameter of 170nm. We further employed SiO2@MgAl-LDH nanocomposite as a nanocarrier to deliver methotrexate (MTX), a chemotherapy drug, to the human osteosarcoma cell (U2OS) and found that MTX delivered by SiO2@MgAl-LDH nanocomposite apparently inhibited the U2OS cell growth. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Chemically and compositionally modified solid solution disordered multiphase nickel hydroxide positive electrode for alkaline rechargeable electrochemical cells

    DOEpatents

    Ovshinsky, Stanford R.; Corrigan, Dennis; Venkatesan, Srini; Young, Rosa; Fierro, Christian; Fetcenko, Michael A.

    1994-01-01

    A high capacity, long cycle life positive electrode for use in an alkaline rechargeable electrochemical cell comprising: a solid solution nickel hydroxide material having a multiphase structure that comprises at least one polycrystalline .gamma.-phase including a polycrystalline .gamma.-phase unit cell comprising spacedly disposed plates with at least one chemical modifier incorporated around the plates, the plates having a range of stable intersheet distances corresponding to a 2.sup.+ oxidation state and a 3.5.sup.+, or greater, oxidation state; and at least one compositional modifier incorporated into the solid solution nickel hydroxide material to promote the multiphase structure.

  3. Ab initio calculations on the positive ions of the alkaline-earth oxides, fluorides, and hydroxides

    NASA Technical Reports Server (NTRS)

    Partridge, H.; Langhoff, S. R.; Bauschlicher, C. W., Jr.

    1986-01-01

    Theoretical dissociation energies are presented for the alkaline-earth fluoride, hydroxide, and oxide positive ions that are considered to be accurate to 0.1-0.2 eV. The r(e) for the positive ions are found to be consistently shorter than the corresponding neutrals by 0.07 + or -0.02 A. The bonding in the ground states is demonstrated to be of predominantly M + 2 X - character. The a 3 Pi and A 1 Pi are found to lie considerably above the X 1 Sigma + ground states of the alkaline-earth fluoride and hydroxide positive ions. The overall agreement of the theoretical ionization potentials with the available experimental appearance potentials is satisfactory; these values should represent the most accurate and consistent set available.

  4. Different arsenate and phosphate incorporation effects on the nucleation and growth of iron(III) (Hydr)oxides on quartz.

    PubMed

    Neil, Chelsea W; Lee, Byeongdu; Jun, Young-Shin

    2014-10-21

    Iron(III) (hydr)oxides play an important role in the geochemical cycling of contaminants in natural and engineered aquatic systems. The ability of iron(III) (hydr)oxides to immobilize contaminants can be related to whether the precipitates form heterogeneously (e.g., at mineral surfaces) or homogeneously in solution. Utilizing grazing incidence small-angle X-ray scattering (GISAXS), we studied heterogeneous iron(III) (hydr)oxide nucleation and growth on quartz substrates for systems containing arsenate and phosphate anions. For the iron(III) only system, the radius of gyration (Rg) of heterogeneously formed precipitates grew from 1.5 to 2.5 (± 1.0) nm within 1 h. For the system containing 10(-5) M arsenate, Rg grew from 3.6 to 6.1 (± 0.5) nm, and for the system containing 10(-5) M phosphate, Rg grew from 2.0 to 4.0 (± 0.2) nm. While the systems containing these oxyanions had more growth, the system containing only iron(III) had the most nucleation events on substrates. Ex situ analyses of homogeneously and heterogeneously formed precipitates indicated that precipitates in the arsenate system had the highest water content and that oxyanions may bridge iron(III) hydroxide polymeric embryos to form a structure similar to ferric arsenate or ferric phosphate. These new findings are important because differences in nucleation and growth rates and particle sizes will impact the number of available reactive sites and the reactivity of newly formed particles toward aqueous contaminants.

  5. Anticancer nanodelivery system with controlled release property based on protocatechuate–zinc layered hydroxide nanohybrid

    PubMed Central

    Barahuie, Farahnaz; Hussein, Mohd Zobir; Abd Gani, Shafinaz; Fakurazi, Sharida; Zainal, Zulkarnain

    2014-01-01

    Background We characterize a novel nanocomposite that acts as an efficient anticancer agent. Methods This nanocomposite consists of zinc layered hydroxide intercalated with protocatechuate (an anionic form of protocatechuic acid), that has been synthesized using a direct method with zinc oxide and protocatechuic acid as precursors. Results The resulting protocatechuic acid nanocomposite (PAN) showed a basal spacing of 12.7 Å, indicating that protocatechuate was intercalated in a monolayer arrangement, with an angle of 54° from the Z-axis between the interlayers of the zinc layered hydroxide, and an estimated drug loading of about 35.7%. PAN exhibited the properties of a mesoporous type material, with greatly enhanced thermal stability of protocatechuate as compared to its free counterpart. The presence of protocatechuate in the interlayers of the zinc layered hydroxide was further supported by Fourier transform infrared spectroscopy. Protocatechuate was released from PAN in a slow and sustained manner. This mechanism of release was well represented by a pseudo-second order kinetics model. PAN has shown increased cytotoxicity compared to the free form of protocatechuic acid in all cancer cell lines tested. Tumor growth suppression was extensive, particularly in HepG2 and HT29 cell lines. Conclusion PAN is suitable for use as a controlled release formulation, and our in vitro evidence indicates that PAN is an effective anticancer agent. PAN may have potential as a chemotherapeutic drug for human cancer. PMID:25061291

  6. Self-grown oxy-hydroxide@ nanoporous metal electrode for high-performance supercapacitors.

    PubMed

    Kang, JianLi; Hirata, Akihiko; Qiu, H-J; Chen, LuYang; Ge, XingBo; Fujita, Takeshi; Chen, MingWei

    2014-01-15

    A binder-free self-grown oxy-hydroxide@nanoporous Ni-Mn hybrid electrode with high capacitance and cyclic stability is fabricated by electrochemical polarization of a dealloyed nanoporous Ni-Mn alloy. Combined with the low material costs, high electrochemical stability, and environmentally friendly nature, this novel electrode holds great promise for applications in high-capacity commercial supercapacitors. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Nanosheets of oxides and hydroxides: Ultimate 2D charge-bearing functional crystallites.

    PubMed

    Ma, Renzhi; Sasaki, Takayoshi

    2010-12-01

    A wide variety of cation-exchangeable layered transition metal oxides and their relatively rare counterparts, anion-exchangeable layered hydroxides, have been exfoliated into individual host layers, i.e., nanosheets. Exfoliation is generally achieved via a high degree of swelling, typically driven either by intercalation of bulky organic ions (quaternary ammonium cations, propylammonium cations, etc.) for the layered oxides or by solvation with organic solvents (formamide, butanol, etc.) for the hydroxides. Ultimate two-dimensional (2D) anisotropy for the nanosheets, with thickness of around one nanometer versus lateral size ranging from submicrometer to several tens of micrometers, allows them to serve either as an ideal quantum system for fundamental study or as a basic building block for functional assembly. The charge-bearing inorganic macromolecule-like nanosheets can be assembled or organized through various solution-based processing techniques (e.g., flocculation, electrostatic sequential deposition, or the Langmuir-Blodgett method) to produce a range of nanocomposites, multilayer nanofilms, and core-shell nanoarchitectures, which have great potential for electronic, magnetic, optical, photochemical, and catalytic applications.

  8. Efficient Sorption and Removal of Perfluoroalkyl Acids (PFAAs) from Aqueous Solution by Metal Hydroxides Generated in Situ by Electrocoagulation.

    PubMed

    Lin, Hui; Wang, Yujuan; Niu, Junfeng; Yue, Zhihan; Huang, Qingguo

    2015-09-01

    Removal of environmentally persistent perfluoroalkyl acids (PFAAs), that is, perfluorooctanesulfonate (PFOS) and perfluorocarboxylic acids (PFCAs, C4 ∼ C10) were investigated through sorption on four metal hydroxide flocs generated in situ by electrocoagulation in deionized water with 10 mM NaCl as supporting electrolyte. The results indicated that the zinc hydroxide flocs yielded the highest removal efficiency with a wide range concentration of PFOA/PFOS (1.5 μM ∼ 0.5 mM) at the zinc dosage <150 mg L(-1) with the energy consumption <0.18 Wh L(-1). The sorption kinetics indicated that the zinc hydroxide flocs had an equilibrium adsorbed amount (qe) up to 5.74/7.69 mmol g(-1) (Zn) for PFOA/PFOS at the initial concentration of 0.5 mM with an initial sorption rate (v0) of 1.01 × 10(3)/1.81 × 10(3) mmol g(-1) h(-1). The sorption of PFOA/PFOS reached equilibrium within <10 min. The sorption mechanisms of PFAAs on the zinc hydroxide flocs were proposed based on the investigation of various driving forces. The results indicated that the hydrophobic interaction was primarily responsible for the PFAAs sorption. The electrocoagulation process with zinc anode may have a great potential for removing PFAAs from industrial wastewater as well as contaminated environmental waterbody.

  9. Mechanochemical synthesis of dodecyl sulfate anion (DS-) intercalated Cu-Al layered double hydroxide

    NASA Astrophysics Data System (ADS)

    Qu, Jun; He, Xiaoman; Lei, Zhiwu; Zhang, Qiwu; Liu, Xinzhong

    2017-12-01

    Dodecyl sulfate anion (DS-) was successfully intercalated into the gallery space of Cu-Al layered double hydroxides (LDH) by a non-heating mechanochemical route, in which basic cupric carbonate (Cu2(OH)2CO3) and aluminum hydroxide (Al(OH)3) were first dry ground and then agitated in SDS solution under ambient environment. The organics modified Cu-Al LDH showed good adsorption ability toward 2,4-dichlorophenoxyacetic acid (2, 4-D). The prepared samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), CHS elemental analysis and Scanning electron microscopy (SEM). The LDH precursor prepared by ball-milling could directly react with SDS molecules forming a pure phase of DS- pillared Cu-Al LDH, which was not observed with the LDH product through the ion-exchange of DS- at room temperature. The process introduced here may be applied to manufacture other types of organic modified composites for pollutants removal and other applications.

  10. Herbicide-Intercalated Zinc Layered Hydroxide Nanohybrid for a Dual-Guest Controlled Release Formulation

    PubMed Central

    Hussein, Mohd Zobir; Rahman, Nor Shazlirah Shazlyn Abdul; Sarijo, Siti H.; Zainal, Zulkarnain

    2012-01-01

    Herbicides, namely 4-(2,4-dichlorophenoxy) butyrate (DPBA) and 2-(3-chlorophenoxy) propionate (CPPA), were intercalated simultaneously into the interlayers of zinc layered hydroxide (ZLH) by direct reaction of zinc oxide with both anions under aqueous environment to form a new nanohybrid containing both herbicides labeled as ZCDX. Successful intercalation of both anions simultaneously into the interlayer gallery space of ZLH was studied by PXRD, with basal spacing of 28.7 Å and supported by FTIR, TGA/DTG and UV-visible studies. Simultaneous release of both CPPA and DPBA anions into the release media was found to be governed by a pseudo second-order equation. The loading and percentage release of the DPBA is higher than the CPPA anion, which indicates that the DPBA anion was preferentially intercalated into and released from the ZLH interlayer galleries. This work shows that layered single metal hydroxide, particularly ZLH, is a suitable host for the controlled release formulation of two herbicides simultaneously. PMID:22837696

  11. Calcium hydroxide as a processing base in alkali-aided pH-shift protein recovery process.

    PubMed

    Paker, Ilgin; Jaczynski, Jacek; Matak, Kristen E

    2017-02-01

    Protein may be recovered by using pH shifts to solubilize and precipitate protein. Typically, sodium hydroxide is used as the processing base; however, this has been shown to significantly increase sodium in the final recovered protein. Protein was extracted from black bullhead catfish (Ameiurus melas) using a pH-shift method. Protein was solubilized using either sodium hydroxide (NaOH) or calcium hydroxide (Ca(OH) 2 ) and precipitated at pH 5.5 using hydrochloric acid (HCl). Protein solubility was greater when Ca(OH) 2 was used compared to NaOH during this process. Using Ca(OH) 2 as the processing base yielded the greatest lipid recovery (P < 0.05) at 77 g 100 g -1 , whereas the greatest (P < 0.05) protein recovery yield was recorded as 53 g 100 g -1 protein using NaOH. Protein solubilized with Ca(OH) 2 had more (P < 0.05) calcium in the protein fraction, whereas using NaOH increased (P < 0.05) sodium content. Results of our study showed that protein solubility was increased and the recovered protein had significantly more calcium when Ca(OH) 2 was used as the processing base. Results showed both NaOH and Ca(OH) 2 to be an effective processing base for pH-shift protein recovery processes. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  12. Rapid mass production of two-dimensional metal oxides and hydroxides via the molten salts method

    PubMed Central

    Hu, Zhimi; Xiao, Xu; Jin, Huanyu; Li, Tianqi; Chen, Ming; Liang, Zhun; Guo, Zhengfeng; Li, Jia; Wan, Jun; Huang, Liang; Zhang, Yanrong; Feng, Guang; Zhou, Jun

    2017-01-01

    Because of their exotic electronic properties and abundant active sites, two-dimensional (2D) materials have potential in various fields. Pursuing a general synthesis methodology of 2D materials and advancing it from the laboratory to industry is of great importance. This type of method should be low cost, rapid and highly efficient. Here, we report the high-yield synthesis of 2D metal oxides and hydroxides via a molten salts method. We obtained a high-yield of 2D ion-intercalated metal oxides and hydroxides, such as cation-intercalated manganese oxides (Na0.55Mn2O4·1.5H2O and K0.27MnO2·0.54H2O), cation-intercalated tungsten oxides (Li2WO4 and Na2W4O13), and anion-intercalated metal hydroxides (Zn5(OH)8(NO3)2·2H2O and Cu2(OH)3NO3), with a large lateral size and nanometre thickness in a short time. Using 2D Na2W4O13 as an electrode, a high performance electrochemical supercapacitor is achieved. We anticipate that our method will enable new path to the high-yield synthesis of 2D materials for applications in energy-related fields and beyond. PMID:28555669

  13. Regenerative endodontic treatment (revascularization) of immature necrotic molars medicated with calcium hydroxide: a case series.

    PubMed

    Cehreli, Zafer C; Isbitiren, Beste; Sara, Sezgi; Erbas, Gizem

    2011-09-01

    Revascularization is an emerging regenerative treatment protocol with little published data available in immature molar teeth. The present case series demonstrates the outcome of revascularization treatment with intracanal medicament of calcium hydroxide in immature necrotic molars. Immature necrotic permanent first molars (n = 6) of patients 8-11 years old were treated by a revascularization protocol that used 2.5% NaOCl irrigation, medication with calcium hydroxide placed in the coronal third of the root canals, induction of apical bleeding, and coronal sealing with white mineral trioxide aggregate. Among the treated teeth, 4 molars had undergone prior root canal instrumentation by the referring dentists. National Institutes of Health Image-J program with TurboReg plug-in was used for standardization of the radiographs and to determine the increase in root length and root width. After a follow-up period of 10 months, all teeth demonstrated radiographic evidence of complete periapical healing, progressive thickening of dentinal walls, and continued apical development in the absence of clinical symptoms. Two uninstrumented molars showed a positive response to cold testing at 9 months. On the basis of a follow-up period of 10 months, the present cases demonstrate a favorable outcome of the revascularization procedure in immature necrotic molars by using calcium hydroxide medication in the coronal third of the root canals. Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  14. The effectiveness of sodium hydroxide (NaOH) and sodium carbonate (Na2CO3) on the impurities removal of saturated salt solution

    NASA Astrophysics Data System (ADS)

    Pujiastuti, C.; Ngatilah, Y.; Sumada, K.; Muljani, S.

    2018-01-01

    Increasing the quality of salt can be done through various methods such as washing (hydro-extraction), re-crystallization, ion exchange methods and others. In the process of salt quality improvement by re-crystallization method where salt product diluted with water to form saturated solution and re-crystallized through heating process. The quality of the salt produced is influenced by the quality of the dissolved salt and the crystallization mechanism applied. In this research is proposed a concept that before the saturated salt solution is recrystallized added a chemical for removal of the impurities such as magnesium ion (Mg), calcium (Ca), potassium (K) and sulfate (SO4) is contained in a saturated salt solution. The chemical reagents that used are sodium hydroxide (NaOH) 2 N and sodium carbonate (Na2CO3) 2 N. This research aims to study effectiveness of sodium hydroxide and sodium carbonate on the impurities removal of magnesium (Mg), calcium (Ca), potassium (K) and sulfate (SO4). The results showed that the addition of sodium hydroxide solution can be decreased the impurity ions of magnesium (Mg) 95.2%, calcium ion (Ca) 45%, while the addition of sodium carbonate solution can decreased magnesium ion (Mg) 66.67% and calcium ion (Ca) 77.5%, but both types of materials are not degradable sulfate ions (SO4). The sodium hydroxide solution more effective to decrease magnesium ion than sodium carbonate solution, and the sodium carbonate solution more effective to decrease calcium ion than sodium hydroxide solution.

  15. Materials properties of hafnium and zirconium silicates: Metal interdiffusion and dopant penetration studies

    NASA Astrophysics Data System (ADS)

    Quevedo Lopez, Manuel Angel

    Hafnium and Zirconium based gate dielectrics are considered potential candidates to replace SiO2 or SiON as the gate dielectric in CMOS processing. Furthermore, the addition of nitrogen into this pseudo-binary alloy has been shown to improve their thermal stability, electrical properties, and reduce dopant penetration. Because CMOS processing requires high temperature anneals (up to 1050°C), it is important to understand the diffusion properties of any metal associated with the gate dielectric in silicon at these temperatures. In addition, dopant penetration from the doped polysilicon gate into the Si channel at these temperatures must also be studied. Impurity outdiffusion (Hf, Zr) from the dielectric, or dopant (B, As, P) penetration through the dielectric into the channel region would likely result in deleterious effects upon the carrier mobility. In this dissertation extensive thermal stability studies of alternate gate dielectric candidates ZrSixOy and HfSixO y are presented. Dopant penetration studies from doped-polysilicon through HfSixOy and HfSixOyNz are also presented. Rutherford Backscattering Spectroscopy (RBS), Heavy Ion RBS (HI-RBS), X-ray Photoelectron Spectroscopy (XPS), High Resolution Transmission Electron Microscopy (HR-TEM), and Time of Flight and Dynamic Secondary Ion Mass Spectroscopy (ToF-SIMS, D-SIMS) methods were used to characterize these materials. The dopant diffusivity is calculated by modeling of the dopant profiles in the Si substrate. In this disseration is reported that Hf silicate films are more stable than Zr silicate films, from the metal interdiffusion point of view. On the other hand, dopant (B, As, and P) penetration is observed for HfSixO y films. However, the addition of nitrogen to the Hf - Si - O systems improves the dopant penetration properties of the resulting HfSi xOyNz films.

  16. Histological analysis of the biocompatibility of calcium hydroxide associated with a new vehicle.

    PubMed

    Simi Junior, Jacy; Machado, Ricardo; Souza, Cássio José Alves de; Loyola, Adriano Motta; Vansan, Luiz Pascoal; Antoniazzi, João Humberto

    2015-01-01

    Several substances have been researched to act as vehicles associated with calcium hydroxide. The specific type of vehicle is directly related to the effectiveness of the ionic dissociation, antimicrobial action, and biocompatibility of this medication. To make a histological evaluation of the biocompatibility of calcium hydroxide associated with a new vehicle (triethanolamine), compared with polyethylene glycol, saline solution, and olive oil. Fifty mice of guinea pig species were randomly divided into five groups (n = 10) according to each vehicle used--Group 1: calcium hydroxide, Group 2: triethanolamine, Group 3: polyethylene glycol, Group 4: saline solution, and Group 5: olive oil--and further divided into subgroups according to the two analysis periods--(a) 30 and (b) 90 days. Teflon carriers filled with the evaluated substances were placed in standardized bone cavities in the anterior mandible region. The animals were euthanized to perform a histological analysis after the time periods analyzed. In 30 days, specimens from Groups 1, 3, and 5 showed a very pronounced inflammatory response. Specimens from Group 2 showed an inflammatory reaction ranging from mild to severe, with rapid resorption of the material and progressive advancement of osteoid tissue into the teflon carriers. Specimens from Group 4 showed a moderate inflammatory reaction. In 90 days, specimens from Group 1 showed a very pronounced fibrous replacement. In regard to Group 2 specimens, the tested material was solubilized and replaced by newly formed bone tissue. For Groups 3 and 5 specimens, the inflammatory reaction went from acute to moderate. In relation to Group 4 specimens, an organized bone formation process was observed. Specimens from Group 2 showed higher biocompatibility, especially as compared with the specimens from Groups 3 and 5.

  17. Prebiotic Oxidative Polymerization of 2,3 Dimercaptopropanol on the Surface of Iron(III) Hydroxide Oxide

    NASA Technical Reports Server (NTRS)

    Weber, Arthur L.

    1994-01-01

    The oxidation of 2,3-Dimercapto-1-propanol by ferric ions on the surface of iron (III) hydroxide oxide yielded polydisulfide polymers. This polymerization occured readily at low dithiol concentration under mild aqueous conditions. Polydisulfide polymers up to the 15-mer were synthesized from 1 mM dithiol in 5 ml water reacted with iron (III) hydroxide oxide (20 mg, 160 micro mole Fe) for 3 days under anaerobic conditions at 40 C and pH 4. About 91% of the dithiol was converted to short soluble oligomers and 9% to insoluble larger oligomers that were isolated with the mineral phase. Reactions at higher dithiol concentrations with the same ratio of dithiol to mineral gave a higher yield of the larger insoluble oligomers. The relationship of these results to prebiotic polymer synthesis will be discussed.

  18. Anion-exchange membranes derived from quaternized polysulfone and exfoliated layered double hydroxide for fuel cells

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Liu, Wan; Liang, Na; Peng, Pai

    2017-02-15

    Layered double hydroxides (LDH) are prepared by controlling urea assisted homogeneous precipitation conditions. Morphology and crystallinity of LDHs are confirmed by X-ray diffraction and scanning electron microscope. After LDHs are incorporated into quaternized polysulfone membranes, transmission electron microscope is used to observe the exfoliated morphology of LDH sheets in the membranes. The properties of the nanocomposite membranes, including water uptake, swelling ratio, mechanical property and ionic conductivity are investigated. The nanocomposite membrane containing 5% LDH sheets shows more balanced performances, exhibiting an ionic conductivity of 2.36×10{sup −2} S cm{sup −1} at 60 °C. - Graphical abstract: Anion-exchange membrane based onmore » quaternized polysulfone and exfoliated layered double hydroxide is optically transparent and has good ionic properties.« less

  19. Successive potassium hydroxide testing for improved diagnosis of tinea pedis.

    PubMed

    Karaman, Bilge F; Topal, Suhan G; Aksungur, Varol L; Ünal, İlker; İlkit, Macit

    2017-08-01

    In this study, we investigated the role of successive potassium hydroxide (KOH) tests for the diagnosis of tinea pedis with different clinical presentations. The study included 135 patients with 200 lesions that were clinically suspicious for tinea pedis. Three samples of skin scrapings were taken from each lesion in the same session and were examined using a KOH test. This study offers an inexpensive, rapid, and useful technique for the daily practice of clinicians and mycologists managing patients with clinically suspected tinea pedis.

  20. TRANSFORMATION AND MOBILIZATION OF ARSENIC ADSORBED ON GRANULAR FERRIC HYDROXIDE UNDER BIO-REDUCTIVE CONDITIONS

    EPA Science Inventory

    Biotic and abiotic reduction of arsenic (V) and iron (III) influences the partioning of arsenic (As) between the solid and aqueous phases in soils, sediments and wastes. In this study, laboratory experiments on arsenic adsorbed on granular ferric hydroxide (GFH) was performed to ...

  1. Rational design of interfacial properties of ferric (hydr)oxide nanoparticles by adsorption of fatty acids from aqueous solutions.

    PubMed

    Ponnurangam, Sathish; Chernyshova, Irina V; Somasundaran, Ponisseril

    2012-07-24

    Notwithstanding the great practical importance, still open are the questions how, why, and to what extent the size, morphology, and surface charge of metal (hydr)oxide nanoparticles (NPs) affect the adsorption form, adsorption strength, surface density, and packing order of organic (bio)molecules containing carboxylic groups. In this article, we conclusively answer these questions for a model system of ferric (hydr)oxide NPs and demonstrate applicability of the established relationships to manipulating their hydrophobicity and dispersibility. Employing in situ Fourier transform infrared (FTIR) spectroscopy and adsorption isotherm measurements, we study the interaction of 150, 38, and 9 nm hematite (α-Fe(2)O(3)) and ∼4 nm 2-line ferrihydrite with sodium laurate (dodecanoate) in water. We discover that, independent of morphology, an increase in size of the ferric (hydr)oxide NPs significantly improves their adsorption capacity and affinity toward fatty acids. This effect favors the formation of bilayers, which in turn promotes dispersibility of the larger NPs in water. At the same time, the local order in self-assembled monolayer (SAM) strongly depends on the morphological compatibility of the NP facets with the geometry-driven well-packed arrangements of the hydrocarbon chains as well as on the ratio of the chemisorbed to the physically adsorbed carboxylate groups. Surprisingly, the geometrical constraints can be removed, and adsorption capacity can be increased by negatively polarizing the NPs due to promotion of the outer-sphere complexes of the fatty acid. We interpret these findings and discuss their implications for the nanotechnological applications of surface-functionalized metal (hydr)oxide NPs.

  2. Curcumin/turmeric solubilized in sodium hydroxide inhibits HNE protein modification--an in vitro study.

    PubMed

    Kurien, Biji T; Scofield, R Hal

    2007-03-21

    Free radical mediated lipid peroxidation has been implicated in multiple diseases. A major oxidation by-product of this deleterious process is 4-hydroxy-2-nonenal (HNE). HNE is cytotoxic, mutagenic and genotoxic and is involved in disease pathogenesis. Curcumin, a non-steroidal anti-inflammatory agent (occurring as the yellow pigment found in the rhizomes of the perennial herb Curcuma longa known as turmeric), has emerged as the newest "nutraceutical" agent that has been shown to be efficacious against colon cancer and other disorders, including correcting cystic fibrosis defects. Since curcumin has been reported to have anti-oxidant properties we hypothesized that it will inhibit HNE-modification of a protein substrate. Using an ELISA that employed HNE-modification of solid phase antigen following immobilization, we found that the curcumin solubilized in dilute alkali (5mM sodium hydroxide, pH 11) inhibited HNE-protein modification by 65%. Turmeric also inhibited HNE-protein modification similarly (65%) but at a much lower alkali level (130muM sodium hydroxide, pH 7.6). Alkali by itself (5mM sodium hydroxide, pH 11) was found to enhance HNE modification by as much as 267%. Curcumin/turmeric has to inhibit this alkali enhanced HNE-modification prior to inhibiting the normal HNE protein modification induced by HNE. Thus, inhibition of HNE-modification could be a mechanism by which curcumin exerts its antioxidant effects. The pH at which the inhibition of HNE modification of substrate was observed was close to the physiological pH, making this formulation of curcumin potentially useful practically.

  3. Evaluation of pH and calcium ion diffusion from calcium hydroxide pastes and MTA.

    PubMed

    Sáez, María Del M; López, Gabriela L; Atlas, Diana; de la Casa, María L

    2017-04-01

    The aim of this ex vivo study was to evaluate changes in pH and calcium ion diffusion through root dentin from calcium hydroxide (Ca (OH) 2 ) and mineral trioxide aggregate (MTA) pastes at 7, 30 and 60 days; and the relationship between pH and ion diffusion. Thirty-two human premolars were used. Crowns were sectioned and root canals instrumented and filled in with the following preparations: 1) Ca(OH) 2 + distilled water (n=7); 2) Ca(OH) 2 + 0.1% chlorhexidine gluconate (n=7); 3) MTA + distilled water (n=7); 4) MTA + 0.1% chlorhexidine gluconate (CHX) (n=7); 5) distilled water (n=2) (control); 6) 0.1% chlorhexidine gluconate (n=2) (control). The apex and coronary opening were sealed with IRM. Roots were placed in Eppendorf tubes with 1 ml distilled water at 37°C and 100% humidity. At baseline, 7, 30 and 60 days, pH was measured with pH meter, and calcium ion content in the solution was analyzed by atomic absorption spectrophotometry. The data were statistically analyzed using ANOVA, simple linear regression analysis and Pearson's correlation test. The highest pH values were achieved with calcium hydroxide pastes at 60 days (p ≤ 0.05). Calcium ions were released in all groups. The calcium hydroxide paste with distilled water at 60 days had the highest calcium ion value (p ≤ 0.01). There was a positive correlation between calcium and pH values. Sociedad Argentina de Investigación Odontológica.

  4. Rapid synthesis of barium titanate microcubes using composite-hydroxides-mediated avenue

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    He, Xi; Ouyang, Jing, E-mail: jingouyang@csu.edu.cn; Jin, Jiao

    2014-04-01

    Highlights: • Barium titanate oxides microcubes can be synthesized within 1 min. • Composite-hydroxides-mediated strategy provided a possible large scale production. • BST obtained in the strategy showed fairly good crystallinity and tetragonality. - Abstract: This paper reports the rapid synthesis of barium titanate (BaTiO{sub 3}, BTO) microcubes via composite-hydroxides-mediated reaction within 1 min. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersion spectrum (EDS) results confirmed both cubic and tetragonal lattices in the sample and the uniform microcubes with an average size of 1 μm. Ultraviolet–visible (UV–vis) spectrum indicated that the band gap of the BTO powder wasmore » 3.05 eV. Ferroelectric polarization vs. electric field (P–E) tests showed that the ferroelectric domains had formed in the as-synthesized BTO microcubes and sintered ceramics. BTO ceramics sintered at 1100 °C for 3 h showed fairly good tetragonality and possessed a maximum polarization of 0.21 μC/cm{sup 2}, indicating that the sintering temperature for the BTO powders prepared via this method was relatively low. The process and equipment reported herein provided a potential method for the rapid synthesis of titanate based perovskites.« less

  5. Reaction of tris(bipyridine)ruthenium(III) with hydroxide and its application in a solar energy storage system

    PubMed Central

    Creutz, Carol; Sutin, Norman

    1975-01-01

    Irradiation of Ru(bipy)32+ (bipy = 2,2′-bipyridine) with light below 560 nm results in the formation of a charge-transfer excited state potentially capable of reducing water to dihydrogen with concomitant production of Ru(bipy)33+. The latter may be reduced by hydroxide [Formula: see text] to form dioxygen and regenerate the starting complex. The use of these reactions in a cell designed to bring about the photochemical decomposition of water is proposed. The stoichiometry, kinetics, and mechanism of the Ru(bipy)33+-hydroxide reaction have been investigated by conventional and stopped-flow spectrophotometry. The dioxygen yield is a sharp function of pH, attaining its maximum value (about 80%) at pH 9. At low pH (3 and 4.8) the production of ruthenium(II) is first order with kobsd = (1.41 ± 0.04) × 10-4 sec-1 (25°, ionic strength μ = 1.00 M with sodium sulfate). In the intermediate pH range (7.9-10.0) complex kinetics are observed. In the hydroxide range 0.01-0.50 M, ruthenium(II) production is predominantly first order with kobsd = ka[OH-] + kb[OH-]2 sec-1; ka = 148 M-1 sec-1 and kb = 138 M-2 sec-1 (25°, μ = 1.00 M, sodium sulfate). For the ka term, the activation parameters are ΔH‡ = 15.3 ± 1.0 kcal mol-1 and ΔS‡ = 7 ± 3 cal deg-1 mol-1 (1 cal = 4.184 J). An intermediate species (λmax 800 nm) forms at the same rate as ruthenium(II) in this hydroxide range. It disappears with kobsd = 1.2 + 1.1 × 102 [OH-] sec-1 at 25°. Similarly absorbing (λmax 750 to 800 nm) species are generated by the addition of hydroxyl radical to M(bipy)32+/3+ [M = Fe(II), Os(II), Ru(II), Cr(III), Ru(III)] in pulse radiolysis experiments. The kinetics above pH 7 are described in terms of rate-determining nucleophilic attack by hydroxide on the bound bipyridine ring. The hydroxide adduct so generated is tentatively identified with that observed in the pulse radiolysis experiments with Ru(bipy)32+. For reduction of Ru(bipy)33+ by hydrogen peroxide ruthenium(II) production is

  6. Multiple and configurable optical logic systems based on layered double hydroxides and chromophore assemblies.

    PubMed

    Shi, Wenying; Fu, Yi; Li, Zhixiong; Wei, Min

    2015-01-14

    Multiple and configurable fluorescence logic gates were fabricated via self-assembly of layered double hydroxides and various chromophores. These logic gates were operated by observation of different emissions with the same excitation wavelength, which achieve YES, NOT, AND, INH and INHIBIT logic operations, respectively.

  7. SUMMARY REVIEW OF THE HEALTH EFFECTS ASSOCIATED WITH SODIUM HYDROXIDE: HEALTH ISSUE ASSESSMENT

    EPA Science Inventory

    Sodium hydroxide (NaOH) is produced in large quantities in the U.S. and the aerosol may be rebased into the atmosphere. Inhalation of aerosolized NaOH can cause damage to the upper respiratory tract and to the lungs. Rats exposed to a 40% NaOH aerosol in a chronic study showed br...

  8. Cobalt hydroxide nanoflakes and their application as supercapacitors and oxygen evolution catalysts.

    PubMed

    Rovetta, A A S; Browne, M P; Harvey, A; Godwin, I J; Coleman, J N; Lyons, M E G

    2017-09-15

    Finding alternative routes to access and store energy has become a major issue recently. Transition metal oxides have shown promising behaviour as catalysts and supercapacitors. Recently, liquid exfoliation of bulk metal oxides appears to be an effective route which provides access to two-dimensional (2D) nano-flakes, the size of which can be easily selected. These 2D materials exhibit excellent electrochemical charge storage and catalytic activity for the oxygen evolution reaction. In this study, various sized selected cobalt hydroxide nano-flake materials are fabricated by this time efficient and highly reproducible process. Subsquently, the electrochemical properties of the standard size Co(OH) 2 nanoflakes were investigated. The oxide modified electrodes were prepared by spraying the metal oxide flake suspension onto a porous conductive support electrode foam, either glassy carbon or nickel. The cobalt hydroxide/nickel foam system was found to have an overpotential value at 10 mA cm -2 in 1 M NaOH as low as 280 mV and an associated redox capacitance exhibiting numerical values up to 1500 F g -1 , thereby making it a viable dual use electrode.

  9. Cobalt hydroxide nanoflakes and their application as supercapacitors and oxygen evolution catalysts

    NASA Astrophysics Data System (ADS)

    Rovetta, A. A. S.; Browne, M. P.; Harvey, A.; Godwin, I. J.; Coleman, J. N.; Lyons, M. E. G.

    2017-09-01

    Finding alternative routes to access and store energy has become a major issue recently. Transition metal oxides have shown promising behaviour as catalysts and supercapacitors. Recently, liquid exfoliation of bulk metal oxides appears to be an effective route which provides access to two-dimensional (2D) nano-flakes, the size of which can be easily selected. These 2D materials exhibit excellent electrochemical charge storage and catalytic activity for the oxygen evolution reaction. In this study, various sized selected cobalt hydroxide nano-flake materials are fabricated by this time efficient and highly reproducible process. Subsquently, the electrochemical properties of the standard size Co(OH)2 nanoflakes were investigated. The oxide modified electrodes were prepared by spraying the metal oxide flake suspension onto a porous conductive support electrode foam, either glassy carbon or nickel. The cobalt hydroxide/nickel foam system was found to have an overpotential value at 10 mA cm-2 in 1 M NaOH as low as 280 mV and an associated redox capacitance exhibiting numerical values up to 1500 F g-1, thereby making it a viable dual use electrode.

  10. Hupresin Retains Binding Capacity for Butyrylcholinesterase and Acetylcholinesterase after Sanitation with Sodium Hydroxide.

    PubMed

    Onder, Seda; David, Emilie; Tacal, Ozden; Schopfer, Lawrence M; Lockridge, Oksana

    2017-01-01

    Hupresin is a new affinity resin that binds butyrylcholinesterase (BChE) in human plasma and acetylcholinesterase (AChE) solubilized from red blood cells (RBC). Hupresin is available from the CHEMFORASE company. BChE in human plasma binds to Hupresin and is released with 0.1 M trimethylammonium bromide (TMA) with full activity and 10-15% purity. BChE immunopurified from plasma by binding to immobilized monoclonal beads has fewer contaminating proteins than the one-step Hupresin-purified BChE. However, when affinity chromatography on Hupresin follows ion exchange chromatography at pH 4.5, BChE is 99% pure. The membrane bound AChE, solubilized from human RBC with 0.6% Triton X-100, binds to Hupresin and remains bound during washing with sodium chloride. Human AChE is not released in significant quantities with non-denaturing solvents, but is recovered in 1% trifluoroacetic acid. The denatured, partially purified AChE is useful for detecting exposure to nerve agents by mass spectrometry. Our goal was to determine whether Hupresin retains binding capacity for BChE and AChE after Hupresin is washed with 0.1 M NaOH. A 2 mL column of Hupresin equilibrated in 20 mM TrisCl pH 7.5 was used in seven consecutive trials to measure binding and recovery of BChE from 100 mL human plasma. Between each trial the Hupresin was washed with 10 column volumes of 0.1 M sodium hydroxide. A similar trial was conducted with red blood cell AChE in 0.6% Triton X-100. It was found that the binding capacity for BChE and AChE was unaffected by washing Hupresin with 0.1 M sodium hydroxide. Hupresin could be washed with sodium hydroxide at least seven times without losing binding capacity.

  11. Acceptor-type hydroxide graphite intercalation compounds electrochemically formed in high ionic strength solutions.

    PubMed

    Miyazaki, Kohei; Iizuka, Asuka; Mikata, Koji; Fukutsuka, Tomokazu; Abe, Takeshi

    2017-09-05

    The intercalation of hydroxide ions (OH - ) into graphite formed graphite intercalation compounds (GICs) in high ionic strength solutions. GICs of solvated OH - anions with two water molecules (OH - ·2H 2 O) in alkaline aqueous solutions and GICs of only OH - anions in a molten NaOH-KOH salt solution were electrochemically synthesized.

  12. Molecular dynamics in aluminum layered double hydroxides as studied by 1H T1ρ NMR measurements

    NASA Astrophysics Data System (ADS)

    Vyalikh, Anastasia; Wang, De-Yi; Wagenknecht, Udo; Heinrich, Gert; Scheler, Ulrich

    2011-06-01

    Proton dynamics in pristine and organically-modified layered double hydroxide has been studied by 1H T1ρ. Inverse Laplace transform with spectral resolution results in a correlation of T1ρ and chemical shift. In LDH two contributions are resolved. They are assigned to the metal hydroxides, forming the LDH sheets (4-8 ms), and mobile interlayer water (2 ms). Apparent T1ρ values of OH-protons in surfactant-modified LDH are different in dodecylbenzenesulfonate- (SDBS) and sodium octasulfonate- (C8) modified LDH. This difference is explained by the presence of water in LDH-SDBS. The effects of spin diffusion have been studied by performing 2D 1H RFDR in the LDH-SDBS.

  13. Nanoparticulate iron(III) oxo-hydroxide delivers safe iron that is well absorbed and utilised in humans

    PubMed Central

    Pereira, Dora I.A.; Bruggraber, Sylvaine F.A.; Faria, Nuno; Poots, Lynsey K.; Tagmount, Mani A.; Aslam, Mohamad F.; Frazer, David M.; Vulpe, Chris D.; Anderson, Gregory J.; Powell, Jonathan J.

    2014-01-01

    Iron deficiency is the most common nutritional disorder worldwide with substantial impact on health and economy. Current treatments predominantly rely on soluble iron which adversely affects the gastrointestinal tract. We have developed organic acid-modified Fe(III) oxo-hydroxide nanomaterials, here termed nano Fe(III), as alternative safe iron delivery agents. Nano Fe(III) absorption in humans correlated with serum iron increase (P < 0.0001) and direct in vitro cellular uptake (P = 0.001), but not with gastric solubility. The most promising preparation (iron hydroxide adipate tartrate: IHAT) showed ~80% relative bioavailability to Fe(II) sulfate in humans and, in a rodent model, IHAT was equivalent to Fe(II) sulfate at repleting haemoglobin. Furthermore, IHAT did not accumulate in the intestinal mucosa and, unlike Fe(II) sulfate, promoted a beneficial microbiota. In cellular models, IHAT was 14-fold less toxic than Fe(II) sulfate/ascorbate. Nano Fe(III) manifests minimal acute intestinal toxicity in cellular and murine models and shows efficacy at treating iron deficiency anaemia. From the Clinical Editor This paper reports the development of novel nano-Fe(III) formulations, with the goal of achieving a magnitude less intestinal toxicity and excellent bioavailability in the treatment of iron deficiency anemia. Out of the tested preparations, iron hydroxide adipate tartrate met the above criteria, and may become an important tool in addressing this common condition. PMID:24983890

  14. The importance of proper crystal-chemical and geometrical reasoning demonstrated using layered single and double hydroxides

    PubMed Central

    Richardson, Ian G.

    2013-01-01

    Atomistic modelling techniques and Rietveld refinement of X-ray powder diffraction data are widely used but often result in crystal structures that are not realistic, presumably because the authors neglect to check the crystal-chemical plausibility of their structure. The purpose of this paper is to reinforce the importance and utility of proper crystal-chemical and geometrical reasoning in structural studies. It is achieved by using such reasoning to generate new yet fundamental information about layered double hydroxides (LDH), a large, much-studied family of compounds. LDH phases are derived from layered single hydroxides by the substitution of a fraction (x) of the divalent cations by trivalent. Equations are derived that enable calculation of x from the a parameter of the unit cell and vice versa, which can be expected to be of widespread utility as a sanity test for extant and future structure determinations and computer simulation studies. The phase at x = 0 is shown to be an α form of divalent metal hydroxide rather than the β polymorph. Crystal-chemically sensible model structures are provided for β-Zn(OH)2 and Ni- and Mg-based carbonate LDH phases that have any trivalent cation and any value of x, including x = 0 [i.e. for α-M(OH)2·mH2O phases]. PMID:23719702

  15. Determination of the bactericidal activity of different calcium hydroxide presentations on a dentin model.

    PubMed

    Sinan, A; Adou, A J; Rochd, T; Calas, P

    2007-03-01

    Calcium hydroxide placed as a temporary dressing in the root canal helps sterilize infected canals. Hycal and Roeko calcium hydroxide points are two delayed-action medications containing Ca(OH)2 recommended for root canal treatment. The purpose of this study was to test their bactericidal activity in comparison with that of C-PMCP on Streptococcus sanguins strain NCTC 7823. Artificially infected 4-mm high blocks of dentin obtained from bovine incisors were used as an experimental model (n = 192). After three days of treatment with the two antiseptics, intracanal dentin powder was collected by serial drillings and used to inoculate a culture broth. The turbidity of this broth after 24 hours showed if the bacteria were eliminated or not and was used as criterion of antiseptic efficacy. No bacterial growth was observed in the samples treated with C-PMCP. Hycal had a considerable bactericidal activity with 94% of negative cultures whereas first-generation Roeko points had no activity on the strain of S. sanguis tested.

  16. Effects of morphology and chemical doping on electrochemical properties of metal hydroxides in pseudocapacitors.

    PubMed

    Lee, Gyeonghee; Varanasi, Chakrapani V; Liu, Jie

    2015-02-21

    It is well known that both the structural morphology and chemical doping are important factors that affect the properties of metal hydroxide materials in electrochemical energy storage devices. In this work, an effective method to tailor the morphology and chemical doping of metal hydroxides is developed. It is shown that the morphology and the degree of crystallinity of Ni(OH)2 can be changed by adding glucose in the ethanol-mediated solvothermal synthesis. Ni(OH)2 produced in this manner exhibited an increased specific capacitance, which is partially attributed to its increased surface area. Interestingly, the effect of morphology on cobalt doped-Ni(OH)2 is found to be more effective at low cobalt contents than at high cobalt contents in terms of improving the electrochemical performance. This result reveals the existence of competitive effects between chemical doping and morphology change. These findings will provide important insights to design effective materials for energy storage devices.

  17. Enhancement of the coercivity in Co-Ni layered double hydroxides by increasing basal spacing.

    PubMed

    Zhang, Cuijuan; Tsuboi, Tomoya; Namba, Hiroaki; Einaga, Yasuaki; Yamamoto, Takashi

    2016-09-14

    The magnetic properties of layered double hydroxides (LDH) containing transition metal ions can still develop, compared with layered metal hydroxide salts which exhibit structure-dependent magnetism. In this article, we report the preparation of a hybrid magnet composed of Co-Ni LDH and n-alkylsulfonate anions (Co-Ni-CnSO3 LDH). As Co-Ni LDH is anion-exchangeable, we can systematically control the interlayer spacing by intercalating n-alkylsulfonates with different carbon numbers. The magnetic properties were examined with temperature- and field-dependent magnetization measurements. As a result, we have revealed that the coercive field depends on the basal spacing. It is suggested that increasing the basal spacing varies the competition between the in-plane superexchange interactions and long-range out-of-plane dipolar interactions. Moreover, a jump in the coercive field at around 20 Å of the basal spacing is assumed to be the modification of the magnetic ordering in Co-Ni-CnSO3 LDH.

  18. Behaviour of the surface hydroxide groups of exfoliated kaolinite in the gas phase and during water adsorption.

    PubMed

    Táborosi, Attila; Szilágyi, Róbert K

    2016-02-14

    The chemical and physical properties, and thus the reactivity of phylloaluminosilicates can be tailored by intercalation, delamination, and exfoliation processes. In going from the periodic crystalline to the molecular exfoliated phase, surface defects and modifications gain importance as each face of the phylloaluminosilicate comes in direct contact with the external chemical environment. In this work, we extend our earlier studies on the molecular cluster modelling of exfoliated kaolinite sheets by evaluating the positions and orientations of surface hydroxide groups and bridging oxide anions, as the sites of reactivity. The previous focus on the inner chemical environment of a single kaolinite layer is shifted to the surface exposed octahedral aluminium-hydroxide and tetrahedral silicon-oxide sheets. The combination of semi-empirical, ab initio wave function, and density functional calculations unanimously support the amphoteric nature of the surface hydroxide groups with respect to H-bonding donor/acceptor capabilities. To a lesser extent, we observe the same for the bridging oxide anions. This is in contrast to the crystalline phase, which manifests only donor orientation for maintaining an inter-layer H-bond network. These results suggest that both electrophilic and nucleophilic characteristics of the octahedral and tetrahedral sheets need to be considered during intercalation and concomitant exfoliation of the kaolinite sheets.

  19. Processing development of 4 tantalum carbide-hafnium carbide and related carbides and borides for extreme environments

    NASA Astrophysics Data System (ADS)

    Gaballa, Osama Gaballa Bahig

    Carbides, nitrides, and borides ceramics are of interest for many applications because of their high melting temperatures and good mechanical properties. Wear-resistant coatings are among the most important applications for these materials. Materials with high wear resistance and high melting temperatures have the potential to produce coatings that resist degradation when subjected to high temperatures and high contact stresses. Among the carbides, Al4SiC4 is a low density (3.03 g/cm3), high melting temperature (>2000°C) compound, characterized by superior oxidation resistance, and high compressive strength. These desirable properties motivated this investigation to (1) obtain high-density Al4SiC4 at lower sintering temperatures by hot pressing, and (2) to enhance its mechanical properties by adding WC and TiC to the Al4SiC4. Also among the carbides, tantalum carbide and hafnium carbide have outstanding hardness; high melting points (3880°C and 3890°C respectively); good resistance to chemical attack, thermal shock, and oxidation; and excellent electronic conductivity. Tantalum hafnium carbide (Ta4HfC 5) is a 4-to-1 ratio of TaC to HfC with an extremely high melting point of 4215 K (3942°C), which is the highest melting point of all currently known compounds. Due to the properties of these carbides, they are considered candidates for extremely high-temperature applications such as rocket nozzles and scramjet components, where the operating temperatures can exceed 3000°C. Sintering bulk components comprised of these carbides is difficult, since sintering typically occurs above 50% of the melting point. Thus, Ta4 HfC5 is difficult to sinter in conventional furnaces or hot presses; furnaces designed for very high temperatures are expensive to purchase and operate. Our research attempted to sinter Ta4HfC5 in a hot press at relatively low temperature by reducing powder particle size and optimizing the powder-handling atmosphere, milling conditions, sintering

  20. Facile synthesis of nickel-cobalt double hydroxide nanosheets with high rate capability for application in supercapacitor

    NASA Astrophysics Data System (ADS)

    Wang, Minmin; Xue, Junying; Zhang, Fangming; Ma, Wenle; Cui, Hongtao

    2015-02-01

    In this work, nickel-cobalt double hydroxide nanosheets with high rate capability are prepared by a facile epoxide precipitation route. The synthetic procedure includes an oxidization step using ammonium persulfate as oxidant and a precipitation step using propylene oxide as precipitation agent. As shown in the results of electrochemical characterization, high specific capacitance of 2548 F g-1 for this material can be obtained at current density of 0.9 A g-1 in aqueous solution of 3 mol L-1 KOH. It is surprising to notice that the capacitance of material still remains 1587 F g-1 at high current density of 35.7 A g-1. These results demonstrate that the as-prepared nickel-cobalt double hydroxide nanosheets are promising electrode material for supercapacitor application as a primary power source.

  1. Thermal conductivity and thermal boundary resistance of atomic layer deposited high-k dielectric aluminum oxide, hafnium oxide, and titanium oxide thin films on silicon

    NASA Astrophysics Data System (ADS)

    Scott, Ethan A.; Gaskins, John T.; King, Sean W.; Hopkins, Patrick E.

    2018-05-01

    The need for increased control of layer thickness and uniformity as device dimensions shrink has spurred increased use of atomic layer deposition (ALD) for thin film growth. The ability to deposit high dielectric constant (high-k) films via ALD has allowed for their widespread use in a swath of optical, optoelectronic, and electronic devices, including integration into CMOS compatible platforms. As the thickness of these dielectric layers is reduced, the interfacial thermal resistance can dictate the overall thermal resistance of the material stack compared to the resistance due to the finite dielectric layer thickness. Time domain thermoreflectance is used to interrogate both the thermal conductivity and the thermal boundary resistance of aluminum oxide, hafnium oxide, and titanium oxide films on silicon. We calculate a representative design map of effective thermal resistances, including those of the dielectric layers and boundary resistances, as a function of dielectric layer thickness, which will be of great importance in predicting the thermal resistances of current and future devices.

  2. Strategy for synthesizing quantum dot-layered double hydroxide nanocomposites and their enhanced photoluminescence and photostability.

    PubMed

    Cho, Seungho; Jung, Sungwook; Jeong, Sanghwa; Bang, Jiwon; Park, Joonhyuck; Park, Youngrong; Kim, Sungjee

    2013-01-08

    Layered double hydroxide-quantum dot (LDH-QD) composites are synthesized via a room temperature LDH formation reaction in the presence of QDs. InP/ZnS (core/shell) QD, a heavy metal free QD, is used as a model constituent. Interactions between QDs (with negative zeta potentials), decorated with dihydrolipoic acids, and inherently positively charged metal hydroxide layers of LDH during the LDH formations are induced to form the LDH-QD composites. The formation of the LDH-QD composites affords significantly enhanced photoluminescence quantum yields and thermal- and photostabilities compared to their QD counterparts. In addition, the fluorescence from the solid LDH-QD composite preserved the initial optical properties of the QD colloid solution without noticeable deteriorations such as red-shift or deep trap emission. Based on their advantageous optical properties, we also demonstrate the pseudo white light emitting diode, down-converted by the LDH-QD composites.

  3. Sodium hydroxide anodization of Ti-Al-4V adherends

    NASA Technical Reports Server (NTRS)

    Filbey, Jennifer A.; Wightman, J. P.; Progar, D. J.

    1987-01-01

    The use of sodium hydroxide anodization (SHA) for Ti-6Al-4V adherends is examined. The SHA surface is evaluated using SEM, X-ray photoelectron spectroscopy, and Auger electron spectroscopy. The SHA procedures of Kennedy et al. (1983) were employed in this experiment. The photomicrographs of the SHA (sandblasted) and PSHA (sandblasted and pickled) oxide surface reveal that the two surfaces differ. The PSHA is patchy and similar to a chromic acid anodization surface and the porosity of the PSHA is more uniform than the SHA surface. The compositions of the surfaces are studied. It is noted that SHA is an effective pretreatment for Ti-6Al-4V adherends.

  4. Tungstocobaltate-pillared layered double hydroxides: Preparation, characterization, magnetic and catalytic properties

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wei Xiaocui; Baicheng College of Higher Medicine, Baicheng 137000; Fu Youzhi

    2008-06-15

    A new polyoxometalate anion-pillared layered double hydroxide (LDH) was prepared by aqueous ion exchange of a Mg-Al LDH precursor in nitrate form with the tungstocobaltate anions [CoW{sub 12}O{sub 40}]{sup 5-}. The physicochemical properties of the product were characterized by the methods of powder X-ray diffraction, elemental analysis, infrared spectroscopy, thermogravimetric analysis and cyclic voltammetry. It was confirmed that [CoW{sub 12}O{sub 40}]{sup 5-} was intercalated between the brucite-type layers of the LDHs without a change in the structure. Magnetic measurement shows the occurrence of antiferromagnetic interactions between the magnetic centers. The investigation of catalytic performance for this sample exhibits high activitymore » for the oxidation of benzaldehyde by hydrogen peroxide. - Graphical abstract: A tungstocobaltate anion [CoW{sub 12}O{sub 40}]{sup 5-} pillared layered double hydroxide (LDH) was prepared by aqueous ion exchange with a Mg-Al LDH precursor in nitrate form, demonstrating that [CoW{sub 12}O{sub 40}]{sup 5-} was intercalated between the brucite-type layers of the LDHs without change in structure. Magnetic measurement shows the occurrence of antiferromagnetic interactions between the magnetic centers. The investigation of catalytic performance for this sample exhibits high activity for the oxidation of benzaldehyde by hydrogen peroxide.« less

  5. Role of Water in Proton-Hydroxide Conductance Across Model and Biological Membranes

    DTIC Science & Technology

    1990-09-01

    esearch - CONTRACT TITLE: Role of water in proton-hydroxide conductan, e across model Maim and biological membranes. RESEARCH OBJECTIVES: Our goals over...establish a model system for measuring proton flux along hydrogen bonded chains of water in hydrophobic phases. TRAINING ACTIVITIES: Three doctoral and two...to general anesthetics. Biochim. Biophys. Acta 944:40- 48. 6. Deamer, D.W. and Nichols, J.W. (1989) Proton flux in model and biological membranes. J

  6. Role of Water in Proton-Hydroxide Conductance Across Model and Biological Membranes

    DTIC Science & Technology

    1989-09-30

    of water in proton-hydroxide conductance across model and biological membranes 12. PERSONAL AUTHOR(S) Deamer, David W. 1 a. TYPE OF REPORT 13b. TIME...identify by block number) The goal of this research is to understand the mechanism of proton translocation in model and biological membranes. The...which conducts protons through hydrogen bonded water, thereby providing an important model for investigating such processes. The Fo subunit of

  7. Role of lauric acid-potassium hydroxide concentration on bacterial contamination of spray washed broiler carcasses

    USDA-ARS?s Scientific Manuscript database

    A series of experiments were conducted to examine reductions in bacterial contamination of broiler carcasses washed in a spray cabinet with various concentrations of lauric acid (LA)-potassium hydroxide (KOH) solutions. Fifty eviscerated carcasses and 5 ceca were obtained from the processing line of...

  8. Synergy and Diffusion with a Borax-Copper Hydroxide Groundline Preservative: 20 Year Update

    Treesearch

    Stan Lebow; Bessie Woodward; Bill Abbott; Mike West

    2014-01-01

    A groundline remedial treatment containing 3.1% copper hydroxide (2% elemental copper) and 40% sodium tetraborate decahydrate (borax) was applied to unseasoned pine posts prior to placement in a test site in southern Mississippi. The soundness of the posts was periodically evaluated using a push test. After 3.5, 6.5, 10, 15 and 20 years, sections were taken from two...

  9. A One-Step Delamination Procedure to Form Single Sheet Iron(III)-(oxy)Hydroxides

    EPA Science Inventory

    The dispersion of a layered iron(III)-(oxy)hydroxide intercalated with dodecanoate (oxGRC12, Fe3IIIO2.18(OH)3.13(C12H23O2)0.56(SO4)0.47; derived from the corr...

  10. The role of SO{sub 4}{sup 2−} surface distribution in arsenic removal by iron oxy-hydroxides

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tresintsi, S.; Simeonidis, K., E-mail: ksime@physics.auth.gr; Department of Mechanical Engineering, University of Thessaly, 38334 Volos

    2014-05-01

    This study investigates the contribution of chemisorbed SO{sub 4}{sup 2−} in improving arsenic removal properties of iron oxy-hydroxides through an ion-exchange mechanism. An analytical methodology was developed for the accurate quantification of sulfate ion (SO{sub 4}{sup 2−}) distribution onto the surface and structural compartments of iron oxy-hydroxides synthesized by FeSO{sub 4} precipitation. The procedure is based on the sequential determination of SO{sub 4}{sup 2−} presence in the diffuse and Stern layers, and the structure of these materials as defined by the sulfate-rich environments during the reaction and the variation in acidity (pH 3–12). Physically sorbed SO{sub 4}{sup 2−}, extracted inmore » distilled water, and physically/chemically adsorbed ions on the oxy-hydroxide's surface leached by a 5 mM NaOH solution, were determined using ion chromatography. Total sulfate content was gravimetrically measured by precipitation as BaSO{sub 4}. To validate the suggested method, results were verified by X-ray photoelectron and Fourier-transformed infrared spectroscopy. Results showed that low precipitation pH-values favor the incorporation of sulfate ions into the structure and the inner double layer, while under alkaline conditions ions shift to the diffuse layer. - Graphical abstract: An analytical methodology for the accurate quantification of sulfate ions (SO{sub 4}{sup 2−}) distribution onto the diffuse layer, the Stern layer and the structure of iron oxy-hydroxides used as arsenic removal agents. - Highlights: • Quantification of sulfate ions presence in FeOOH surface compartments. • Preparation pH defines the distribution of sulfates. • XPS and FTIR verify the presence of SO{sub 4}{sup 2−} in the structure, the Stern layer the diffuse layer of FeOOH. • Chemically adsorbed sulfates control the arsenic removal efficiency of iron oxyhydroxides.« less

  11. Oxidation Characterization of Hafnium-Based Ceramics Fabricated by Hot Pressing and Electric Field-Assisted Sintering

    NASA Technical Reports Server (NTRS)

    Gasch, Matt; Johnson, Sylvia; Marschall, Jochen

    2010-01-01

    Ceramic borides, such as hafnium diboride (HfB2) and zirconium diboride (ZrB2), are members of a family of materials with extremely high melting temperatures referred to as Ultra High Temperature Ceramics (UHTCs). UHTCs constitute a class of promising materials for use in high temperature applications, such as sharp leading edges on future-generation hypersonic flight vehicles, because of their high melting points. The controlled development of microstructure has become important to the processing of UHTCs, with the prospect of improving their mechanical and thermal properties. The improved oxidation resistance of HfB2 has also become important if this material is to be successfully used at temperatures above 2000 C. Furthermore, the use of UHTCs on the leading edges of vehicles traveling at hypersonic speeds will mean exposure to a mixed oxidation environment comprised of both molecular and atomic oxygen. The current study has investigated the high-temperature oxidation behavior of HfB2-based materials in a pure O2 environment, as well as in environments containing different levels of dissociated oxygen (O/O2). Materials were processed by two techniques: conventional hot pressing (HP) and electric field-assisted sintering (FAS). Their oxidation behavior was evaluated in both a tube furnace at 1250 C for 3 hours and in a simulated re-entry environment in the Advanced Heating Facility (AHF) arcjet at NASA Ames Research Center, during a 10-minute exposure to a cold wall heat flux of 250W/sq cm and stagnation pressure of 0.1-0.2 atm. The microstructure of the different materials was characterized before and after oxidation using scanning electron microscopy (SEM).

  12. Aluminum hydroxide coating thickness measurements and brushing tests on K West Basin fuel elements

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pitner, A.L.

    1998-09-11

    Aluminum hydroxide coating thicknesses were measured on fuel elements stored in aluminum canisters in K West Basin using specially developed eddy current probes . The results were used to estimate coating inventories for MCO fuel,loading. Brushing tests successfully demonstrated the ability to remove the coating if deemed necessary prior to MCO loading.

  13. Nanoparticulate iron(III) oxo-hydroxide delivers safe iron that is well absorbed and utilised in humans.

    PubMed

    Pereira, Dora I A; Bruggraber, Sylvaine F A; Faria, Nuno; Poots, Lynsey K; Tagmount, Mani A; Aslam, Mohamad F; Frazer, David M; Vulpe, Chris D; Anderson, Gregory J; Powell, Jonathan J

    2014-11-01

    Iron deficiency is the most common nutritional disorder worldwide with substantial impact on health and economy. Current treatments predominantly rely on soluble iron which adversely affects the gastrointestinal tract. We have developed organic acid-modified Fe(III) oxo-hydroxide nanomaterials, here termed nano Fe(III), as alternative safe iron delivery agents. Nano Fe(III) absorption in humans correlated with serum iron increase (P < 0.0001) and direct in vitro cellular uptake (P = 0.001), but not with gastric solubility. The most promising preparation (iron hydroxide adipate tartrate: IHAT) showed ~80% relative bioavailability to Fe(II) sulfate in humans and, in a rodent model, IHAT was equivalent to Fe(II) sulfate at repleting haemoglobin. Furthermore, IHAT did not accumulate in the intestinal mucosa and, unlike Fe(II) sulfate, promoted a beneficial microbiota. In cellular models, IHAT was 14-fold less toxic than Fe(II) sulfate/ascorbate. Nano Fe(III) manifests minimal acute intestinal toxicity in cellular and murine models and shows efficacy at treating iron deficiency anaemia. This paper reports the development of novel nano-Fe(III) formulations, with the goal of achieving a magnitude less intestinal toxicity and excellent bioavailability in the treatment of iron deficiency anemia. Out of the tested preparations, iron hydroxide adipate tartrate met the above criteria, and may become an important tool in addressing this common condition. Crown Copyright © 2014. Published by Elsevier Inc. All rights reserved.

  14. Adsorption Mechanisms of Trivalent Gold onto Iron Oxy-Hydroxides: From the Molecular Scale to the Model

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cances, Benjamin; Benedetti, Marc; Farges, Francois

    2007-02-02

    Gold is a highly valuable metal that can concentrate in iron-rich exogenetic horizons such as laterites. An improved knowledge of the retention mechanisms of gold onto highly reactive soil components such as iron oxy-hydroxides is therefore needed to better understand and predict the geochemical behavior of this element. In this study, we use EXAFS information and titration experiments to provide a realistic thermochemical description of the sorption of trivalent gold onto iron oxy-hydroxides. Analysis of Au LIII-edge XAFS spectra shows that aqueous Au(III) adsorbs from chloride solutions onto goethite surfaces as inner-sphere square-planar complexes (Au(III)(OH,Cl)4), with dominantly OH ligands atmore » pH > 6 and mixed OH/Cl ligands at lower pH values. In combination with these spectroscopic results, Reverse Monte Carlo simulations were used to constraint the possible sorption sites on the surface of goethite. Based on this structural information, we calculated sorption isotherms of Au(III) on Fe oxy-hydroxides surfaces, using the CD-MUSIC (Charge Distribution - MUlti SIte Complexation) model. The various Au(III)-sorbed species were identified as a function of pH, and the results of these EXAFS+CD-MUSIC models are compared with titration experiments. The overall good agreement between the predicted and measured structural models shows the potential of this combined approach to better model sorption processes of transition elements onto highly reactive solid surfaces such as goethite and ferrihydrite.« less

  15. Formation of Defected Cadmium Ferrite during Hydrothermal Storage of Cadmium-Iron Hydroxides

    NASA Astrophysics Data System (ADS)

    Wolski, W.; Wolska, E.; Kaczmarek, J.

    1994-05-01

    The storage of amorphous coprecipitated Cd(OH) 2 · 2Fe(OH) 3 gel in mother liquor at 150 ± 2°C for 20 hr leads to a crystalline species which, according to X-ray analysis, is composed of cadmium hydroxide nitrate, Cd 3(OH) 5NO 3, cadmium hydroxide, βCd(OH) 2, and a strongly ferrimagnetic spinel phase. The Curie point at 270-280°C was found by thermomagnetic analysis. At that temperature the decomposition of the spinel phase and of the accompanying nonmagnetic phases takes place. IR spectra indicate that during thermomagnetic recording the liberated cadmium oxide and iron oxide form antiferromagnetic cadmium ferrite, with frequencies somewhat displaced in comparison to CdFe 2O 4 annealed at 1000°C. The results indicate that the ferrimagnetic phase (having spinel structure, a unit-cell parameter a of about 8.37 ± 0.01 Å, and a Tc point differing by more than 300°C from that of pure maghemite, γFe 2O 3) is likely to be a defected solid solution of maghemite and cadmium ferrite, of the formula Cd 2+xFe 3+1- x [Fe 3+(5+ x)/3 □ (1- x)/3 ]O 4.

  16. Accidental injury of the inferior alveolar nerve due to the extrusion of calcium hydroxide in endodontic treatment: a case report

    PubMed Central

    2016-01-01

    During clinical endodontic treatment, we often find radiopaque filling material beyond the root apex. Accidental extrusion of calcium hydroxide could cause the injury of inferior alveolar nerve, such as paresthesia or continuous inflammatory response. This case report presents the extrusion of calcium hydroxide and treatment procedures including surgical intervention. A 48 yr old female patient experienced Calcipex II extrusion in to the inferior alveolar canal on left mandibular area during endodontic treatment. After completion of endodontic treatment on left mandibular first molar, surgical intervention was planned under general anesthesia. After cortical bone osteotomy and debridement, neuroma resection and neurorrhaphy was performed, and prognosis was observed. But no improvement in sensory nerve was seen following surgical intervention after 20 mon. A clinician should be aware of extrusion of intracanal medicaments and the possibility of damage on inferior alveolar canal. Injectable type of calcium hydroxide should be applied with care for preventing nerve injury. The alternative delivery method such as lentulo spiral was suggested on the posterior mandibular molar. PMID:26877992

  17. Highly active and durable methanol oxidation electrocatalyst based on the synergy of platinum-nickel hydroxide-graphene.

    PubMed

    Huang, Wenjing; Wang, Hongtao; Zhou, Jigang; Wang, Jian; Duchesne, Paul N; Muir, David; Zhang, Peng; Han, Na; Zhao, Feipeng; Zeng, Min; Zhong, Jun; Jin, Chuanhong; Li, Yanguang; Lee, Shuit-Tong; Dai, Hongjie

    2015-11-25

    Active and durable electrocatalysts for methanol oxidation reaction are of critical importance to the commercial viability of direct methanol fuel cell technology. Unfortunately, current methanol oxidation electrocatalysts fall far short of expectations and suffer from rapid activity degradation. Here we report platinum-nickel hydroxide-graphene ternary hybrids as a possible solution to this long-standing issue. The incorporation of highly defective nickel hydroxide nanostructures is believed to play the decisive role in promoting the dissociative adsorption of water molecules and subsequent oxidative removal of carbonaceous poison on neighbouring platinum sites. As a result, the ternary hybrids exhibit exceptional activity and durability towards efficient methanol oxidation reaction. Under periodic reactivations, the hybrids can endure at least 500,000 s with negligible activity loss, which is, to the best of our knowledge, two to three orders of magnitude longer than all available electrocatalysts.

  18. In situ fabrication of Ni-Co (oxy)hydroxide nanowire-supported nanoflake arrays and their application in supercapacitors.

    PubMed

    Zheng, Xiaoyu; Quan, Honglin; Li, Xiaoxin; He, Hai; Ye, Qinglan; Xu, Xuetang; Wang, Fan

    2016-09-29

    Three-dimensional (3D) hybrid nanostructured arrays grown on a flexible substrate have recently attracted great attention owing to their potential application as supercapacitor electrodes in portable and wearable electronic devices. Here, we report an in situ conversion of Ni-Co active electrode materials for the fabrication of high-performance electrodes. Ni-Co carbonate hydroxide nanowire arrays on carbon cloth were initially synthesized via a hydrothermal method, and they were gradually converted to Ni-Co (oxy)hydroxide nanowire-supported nanoflake arrays after soaking in an alkaline solution. The evolution of the supercapacitor performance of the soaked electrode was investigated in detail. The areal capacitance increases from 281 mF cm -2 at 1 mA cm -2 to 3710 and 3900 mF cm -2 after soaking for 36 h and 48 h, respectively. More interestingly, the electrode also shows an increased capacitance with charge/discharge cycles due to the long-time soaking in KOH solution, suggesting novel cycling durability. The enhancement in capacitive performance should be related to the formation of a unique nanowire-supported nanoflake array architecture, which controls the agglomeration of nanoflakes, making them fully activated. As a result, the facile in situ fabrication of the hybrid architectural design in this study provides a new approach to fabricate high-performance Ni/Co based hydroxide nanostructure arrays for next-generation energy storage devices.

  19. Self-assembly of myristic acid in the presence of choline hydroxide: effect of molar ratio and temperature.

    PubMed

    Arnould, Audrey; Perez, Adrian A; Gaillard, Cédric; Douliez, Jean-Paul; Cousin, Fabrice; Santiago, Liliana G; Zemb, Thomas; Anton, Marc; Fameau, Anne-Laure

    2015-05-01

    Salt-free catanionic systems based on fatty acids exhibit a broad polymorphism by simply tuning the molar ratio between the two components. For fatty acid combined with organic amino counter-ions, very few data are available on the phase behavior obtained as a function of the molar ratio between the counter-ion and the fatty acid. We investigated the choline hydroxide/myristic acid system by varying the molar ratio, R=n(choline hydroxide)/n(myristic acid), and the temperature. Myristic acid ionization state was determined by coupling pH, conductivity and infra-red spectroscopy measurements. Self-assemblies were characterized by small angle neutron scattering and microscopy experiments. Self-assembly thermal behavior was investigated by differential scanning calorimetry, wide angle X-ray scattering and nuclear magnetic resonance. For R<1, ionized and protonated myristic acid molecules coexisted leading to the formation of facetted self-assemblies and lamellar phases. The melting process between the gel and the fluid state of these bilayers induced a structural change from facetted or lamellar objects to spherical vesicles. For R>1, myristic acid molecules were ionized and formed spherical micelles. Our study highlights that both R and temperature are two key parameters to finely control the self-assembly structure formed by myristic acid in the presence of choline hydroxide. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Phosphate adsorption from wastewater using zirconium (IV) hydroxide: Kinetics, thermodynamics and membrane filtration adsorption hybrid system studies.

    PubMed

    Johir, M A H; Pradhan, M; Loganathan, P; Kandasamy, J; Vigneswaran, S

    2016-02-01

    Excessive phosphate in wastewater should be removed to control eutrophication of water bodies. The potential of employing amorphous zirconium (Zr) hydroxide to remove phosphate from synthetic wastewater was studied in batch adsorption experiments and in a submerged membrane filtration adsorption hybrid (MFAH) reactor. The adsorption data satisfactorily fitted to Langmuir, pseudo-first order and pseudo-second order models. Langmuir adsorption maxima at 22 °C and pHs of 4.0, 7.1, and 10.0 were 30.40, 18.50, and 19.60 mg P/g, respectively. At pH 7.1 and temperatures of 40 °C and 60 °C, they were 43.80 and 54.60 mg P/g, respectively. The thermodynamic parameters, ΔG° and ΔS° were negative and ΔH° was positive. FTIR, zeta potential and competitive phosphate, sulphate and nitrate adsorption data showed that the mechanism of phosphate adsorption was inner-sphere complexation. In the submerged MFAH reactor experiment, when Zr hydroxide was added at doses of 1-5 g/L once only at the start of the experiment, the removal of phosphate from 3 L of wastewater containing 10 mg P/L declined after 5 h of operation. However, when Zr hydroxide was repeatedly added at 5 g/L dose every 24 h, satisfactory removal of phosphate was maintained for 3 days. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Glassy-State Stabilization of a Dominant Negative Inhibitor Anthrax Vaccine Containing Aluminum Hydroxide and Glycopyranoside Lipid A Adjuvants

    PubMed Central

    Hassett, Kimberly J.; Vance, David J.; Jain, Nishant K.; Sahni, Neha; Rabia, Lilia A.; Cousins, Megan C.; Joshi, Sangeeta; Volkin, David B.; Middaugh, Russell; Mantis, Nicholas J.; Carpenter, John F.; Randolph, Theodore W.

    2014-01-01

    During transport and storage, vaccines may be exposed to temperatures outside of the range recommended for storage, potentially causing efficacy losses. To better understand and prevent such losses, Dominant Negative Inhibitor (DNI), a recombinant protein antigen for a candidate vaccine against anthrax, was formulated as a liquid and as a glassy lyophilized powder with the adjuvants aluminum hydroxide and glycopyranoside lipid A (GLA). Freeze-thawing of the liquid vaccine caused the adjuvants to aggregate and decreased its immunogenicity in mice. Immunogenicity of liquid vaccines also decreased when stored at 40 °C for 8 weeks, as measured by decreases in neutralizing antibody titers in vaccinated mice. Concomitant with efficacy losses at elevated temperatures, changes in DNI structure were detected by fluorescence spectroscopy and increased deamidation was observed by capillary isoelectric focusing (cIEF) after only 1 week of storage of the liquid formulation at 40 °C. In contrast, upon lyophilization, no additional deamidation after 4 weeks at 40 °C and no detectable changes in DNI structure or reduction in immunogenicity after 16 weeks at 40 °C was observed. Vaccines containing aluminum hydroxide and GLA elicited higher immune responses than vaccines adjuvanted with only aluminum hydroxide, with more mice responding to a single dose. PMID:25581103

  2. Hydroxide stabilization as a new tool for ballast disinfection: Efficacy of treatment on zooplankton

    USGS Publications Warehouse

    Moffitt, Christine M.; Watten, Barnaby J.; Barenburg, Amber; Henquinet, Jeffrey

    2015-01-01

    Effective and economical tools are needed for treating ship ballast to meet new regulatory requirements designed to reduce the introduction of invasive aquatic species from ship traffic. We tested the efficacy of hydroxide stabilization as a ballast disinfection tool in replicated, sequential field trials on board the M/V Ranger III in waters of Lake Superior. Ballast water was introduced into each of four identical 1,320 L stainless steel tanks during a simulated ballasting operation. Two tanks were treated with NaOH to elevate the pH to 11.7 and the remaining two tanks were held as controls without pH alteration. After retention on board for 14–18 h, CO2-rich gas recovered from one of two diesel propulsion engines was sparged into tanks treated with NaOH for 2 h to force conversion of NaOH ultimately to sodium bicarbonate, thereby lowering pH to about 7.1. Prior to gas sparging, the engine exhaust was treated by a unique catalytic converter/wet scrubber process train to remove unwanted combustion byproducts and to provide cooling. The contents of each tank were then drained and filtered through 35-µm mesh plankton nets to collect all zooplankton. The composition and relative survival of zooplankton in each tank were evaluated by microscopy. Zooplankton populations were dominated by rotifers, but copepods and cladocerans were also observed. Hydroxide stabilization was 100% effective in killing all zooplankton present at the start of the tests. Our results suggest hydroxide stabilization has potential to be an effective and practical tool to disinfect ship ballast. Further, using CO2 released from the ship engine reduces emissions and the neutralized by product, sodium bicarbonate, can have beneficial impacts on the aquatic environment.

  3. Role of Water in Proton-Hydroxide Conductance Across Model and Biological Membranes.

    DTIC Science & Technology

    1987-11-10

    Arlington, VA 22217-5000 61153N RR04108 441K712 11. TITLE (Include Security Classification) Role of water in proton-hydroxide conductance across model and...used the gramicidin channel to test properties of transmembrane strands of hydrogen bonded water which would model such defects. Results are described...Gramicidin as a model "proton wire." 2. Effects of homologous series of alcohols on proton flux in liposomes, and the relationship to their anesthetic

  4. Electrochemical formation of hydroxide for enhancing carbon dioxide and acid gas uptake by a solution

    DOEpatents

    Rau, Gregory Hudson

    2014-07-01

    A system for forming metal hydroxide from a metal carbonate utilizes a water electrolysis cell having an acid-producing anode and a hydroxyl-producing cathode immersed in a water solution of sufficient ionic content to allow an electric current to pass between the hydroxyl-producing cathode and the acid-producing anode. A metal carbonate is placed in close proximity to the acid-producing anode. A direct current electrical voltage is provided across the acid-producing anode and the hydroxyl-producing cathode sufficient to generate acid at the acid-producing anode and hydroxyl ions at the hydroxyl-producing cathode. The acid dissolves at least part of the metal carbonate into metal and carbonate ions allowing the metal ions to travel toward the hydroxyl-producing cathode and to combine with the hydroxyl ions to form the metal hydroxide. The carbonate ions travel toward the acid-producing anode and form carbonic acid and/or water and carbon dioxide.

  5. The role of the chemical burns caused by hydroxide ion in the toxicity of dermal exposure to tetramethylammonium ion in a rat model.

    PubMed

    Wu, Chen-Long; Su, Shih-Bin; Lien, Hsiao-Yin; Guo, How-Ran

    2012-11-01

    To evaluate the role of the chemical burns caused by hydroxide ion in the fatal effects of tetramethylammonium ion (TMA) in dermal exposure to tetramethylammonium hydroxide (TMAH), we conducted a rat study consisting of two-step treatments with dermal exposure to NaOH and tetramethylammonium chloride (TMACl). In the first step, NaOH or saline was administered in the gauze on the shaved skin for 5 min, and in the second step, TMAH, TMACl, or saline was administered in the same way. The mean blood pressure (MBP), heart rate (HR), and survival in rats were compared among seven groups. Dermal exposure to saline and then 2.75 M TMACl introduced limited and temporary non-fatal effects. Exposure to 2.75 M NaOH and then saline had almost no effects and caused no deaths. Treatments with more concentrated NaOH or TMACl resulted in suppressions of MBP and HR, and deaths were observed after the dosing of TMACl. The toxicity of dermal exposure to TMA alone is limited, but fatal effects can be introduced by pre-treatment with hydroxide ion. Therefore, the chemical burn caused by hydroxide ion plays an essential role in the toxicity, implicating that effective neutralizing may help decreasing the fatality rate. Copyright © 2012 Elsevier Ltd and ISBI. All rights reserved.

  6. The Efficacy of Calcium Hydroxide Powder mixed with 0.2% Chlorhexidine Digluconate or mixed with Normal Saline as Intracanal Medicament in the Treatment of Apical Periodontitis.

    PubMed

    Menakaya, Ifeoma N; Adegbulugbe, Ilemobade C; Oderinu, Olabisi H; Shaba, Olufemi P

    2015-08-01

    To compare the efficacy of calcium hydroxide powder mixed with 0.2% chlorhexidine digluconate or mixed with normal saline as intracanal medicament in the treatment of apical periodontitis. Subjects were 55 in number aged 17 to 60 years. Two-visit conventional root canal treatment was performed on 70 teeth. The teeth were divided by randomization (balloting) into two groups: control group and experimental group, each with 35 teeth treated with calcium hydroxide mixed with normal saline or with 0.2% chlorhexidine digluconate as intracanal medicament respectively. All treated teeth were evaluated clinically and radiographically for signs and symptom of periapical infection at specified periods postoperatively. Overall efficacy of medicament was rated based on quality guidelines for endodontic treatment by the European Society of Endodontology 2006. A postoperative favorable outcome of 97.1% in the control group and 94.3% in the experimental group was observed at 6-month review. This difference was not statistically significant (p > 0.05). The use of normal saline or 0.2% chlorhexidine digluconate to mix calcium hydroxide used as intracanal medicament during endodontic treatment resulted in high postoperative favorable outcomes. Efficacy of 0.2% chlorhexidine digluconate as a vehicle for mixing calcium hydroxide as an intracanal medicament in the treatment of apical periodontitis is comparable to the efficacy of calcium hydroxide mixed with normal saline.

  7. Accessing the biocompatibility of layered double hydroxide by intramuscular implantation: histological and microcirculation evaluation

    PubMed Central

    Cunha, Vanessa Roberta Rodrigues; de Souza, Rodrigo Barbosa; da Fonseca Martins, Ana Maria Cristina Rebello Pinto; Koh, Ivan Hong Jun; Constantino, Vera Regina Leopoldo

    2016-01-01

    Biocompatibility of layered double hydroxides (LDHs), also known as hydrotalcite-like materials or double metal hydroxides, was investigated by in vivo assays via intramuscular tablets implantation in rat abdominal wall. The tablets were composed by chloride ions intercalated into LDH of magnesium/aluminum (Mg2Al-Cl) and zinc/aluminum (Zn2Al-Cl). The antigenicity and tissue integration capacity of LDHs were assessed histologically after 7 and 28 days post-implantation. No fibrous capsule nearby the LDH was noticed for both materials as well any sign of inflammatory reactions. Sidestream Dark Field imaging, used to monitor in real time the microcirculation in tissues, revealed overall integrity of the microcirculatory network neighboring the tablets, with no blood flow obstruction, bleeding and/or increasing of leukocyte endothelial adhesion. After 28 days Mg2Al-Cl promoted multiple collagen invaginations (mostly collagen type-I) among its fragments while Zn2Al-Cl induced predominantly collagen type–III. This work supports previous results in the literature about LDHs compatibility with living matter, endorsing them as functional materials for biomedical applications. PMID:27480483

  8. Accessing the biocompatibility of layered double hydroxide by intramuscular implantation: histological and microcirculation evaluation.

    PubMed

    Cunha, Vanessa Roberta Rodrigues; de Souza, Rodrigo Barbosa; da Fonseca Martins, Ana Maria Cristina Rebello Pinto; Koh, Ivan Hong Jun; Constantino, Vera Regina Leopoldo

    2016-08-02

    Biocompatibility of layered double hydroxides (LDHs), also known as hydrotalcite-like materials or double metal hydroxides, was investigated by in vivo assays via intramuscular tablets implantation in rat abdominal wall. The tablets were composed by chloride ions intercalated into LDH of magnesium/aluminum (Mg2Al-Cl) and zinc/aluminum (Zn2Al-Cl). The antigenicity and tissue integration capacity of LDHs were assessed histologically after 7 and 28 days post-implantation. No fibrous capsule nearby the LDH was noticed for both materials as well any sign of inflammatory reactions. Sidestream Dark Field imaging, used to monitor in real time the microcirculation in tissues, revealed overall integrity of the microcirculatory network neighboring the tablets, with no blood flow obstruction, bleeding and/or increasing of leukocyte endothelial adhesion. After 28 days Mg2Al-Cl promoted multiple collagen invaginations (mostly collagen type-I) among its fragments while Zn2Al-Cl induced predominantly collagen type-III. This work supports previous results in the literature about LDHs compatibility with living matter, endorsing them as functional materials for biomedical applications.

  9. Holey nickel hydroxide nanosheets for wearable solid-state fiber-supercapacitors.

    PubMed

    Shi, Peipei; Chen, Rong; Li, Li; An, Jianing; Hua, Li; Zhou, Jinyuan; Liu, Bin; Chen, Peng; Huang, Wei; Sun, Gengzhi

    2018-03-28

    Holey nickel hydroxide (Ni(OH) 2 ) nanosheets with a mean thickness of 2 nm are facilely synthesized, and then embedded in carbon nanotube (CNT) scaffolds to construct a hybrid fiber electrode, which shows a high volumetric capacitance of 335.9 F cm -3 at 0.8 A cm -3 and superior rate performance. The hybrid supercapacitor made from the Ni(OH) 2 /CNT fiber can deliver a high specific capacitance of 24.8 F cm -3 and an energy density of 5.8 mW h cm -3 with outstanding mechanical stability under repeated bending conditions.

  10. Quasi-Monolithic Structures for Spaceflight Using Hydroxide-Catalysis Bonding

    NASA Technical Reports Server (NTRS)

    Preston, Alix; Thorpe, J. Ira; Miner, Linda

    2012-01-01

    Future space-based missions will take measurements of the universe with unprecedented results. To do this, these missions will require materials and bonding techniques with ever-increasing stability in order to make their measurements. As an example, the Laser Interferometer Space Antenna (LISA) will detect and observe gravitational waves in the 0.1 mHz to 1 Hz frequency range with strain sensitivities on the order of 10(exp -21) at its most sensitive frequency. To make these measurements, critical components such as the optical bench or telescope support structure, will need to have path-length stabilities of better than 1 pm/(square root)Hz. The baseline construction method for the LISA optical bench is to affix fused silica optical components to a Zerodur baseplate using hydroxide-catalysis bonding (HCB). HCB is a recently developed technique that allows the bonding of glasses, some metals, and silicon carbide with significant strength and stability with a bond thickness of less than a few micrometers. In addition, a wide range of surface profiles can be bonded using only a small amount of hydroxide solution. These characteristics make HCB ideal for adhering optical components in complex optical systems. In addition to being used to construct the LISA optical bench, the HCB technique shows great promise for constructing other structures such as hollow retroreflectors to be used for lunar laser ranging, or a visible nulling coronograph to be used for exo-planet detection. Here we present construction techniques that could be used to make an optical bench, hollow retroreflector, nulling coronograph, or other quasi-monolithic structures using HCB. In addition, we present dimensional stability results of an optical bench that was made using HCB, as well as HCB strength measurements.

  11. Water sorption and solubility of different calcium hydroxide cements.

    PubMed

    Francisconi, Luciana Fávaro; de Freitas, Anderson Pinheiro; Scaffa, Polliana Mendes Candia; Mondelli, Rafael Francisco Lia; Francisconi, Paulo Afonso Silveira

    2009-01-01

    Calcium hydroxide cements have been largely used in deep cavities due to their abilities to stimulate dentin formation. However, their resistance can be relatively low and their solubility relatively high, in many instances. This study evaluated water sorption and solubility of different calcium hydroxide cements, in order to show alterations that may reduce their effectiveness. Five discs (20 mm in diameter and 1.5 mm thick) of three different materials (Biocal, Dycal and Hidro C) were prepared with the aid of a ring-shaped metallic matrix. After being stored at 37 degrees C for 24 h, the discs were weighed on a precision weight scale, dehydrated and weighed again. Immediately after weighing, discs were stored for a week in 50 mL of distilled water at 37 degrees C and, then, weighed again, dehydrated and submitted to a new weighing. The loss of soluble material and its water sorption was obtained from the difference between the initial and the final dry mass of each disc, after 1 week of immersion in water. Data were analyzed for significant differences by two-way ANOVA and Tukey's test (p<0.05). Mean water sorption values (g) +/- standard deviation and percentage (%), for each evaluated cement, were: Biocal (0.006 +/- 0.001 / 2.15); Dycal (0.016 +/- 0.004 / 5.49); and Hidro C (0.025 +/- 0.003 / 8.27). Mean solubility values (g) +/- standard deviation and percentage (%), for each evaluated cement, were: Biocal (0.002 +/- 0.001 / 0.72); Dycal (0.013 +/- 0.004 / 4.21); and Hidro C (0.023 +/- 0.004 / 7.65). Biocal absorbed less water and was less soluble than the other evaluated cements; Hidro C exhibited the highest water sorption and solubility values; and there were significant differences among all evaluated experimental groups.

  12. Aggregate-scale heterogeneity in iron (hydr)oxide reductive transformations

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tufano, K.J.; Benner, S.G.; Mayer, K.U.

    There is growing awareness of the complexity of potential reaction pathways and the associated solid-phase transformations during the reduction of Fe (hydr)oxides, especially ferrihydrite. An important observation in static and advective-dominated systems is that microbially produced Fe(II) accelerates Ostwald ripening of ferrihydrite, thus promoting the formation of thermodynamically more stable ferric phases (lepidocrocite and goethite) and, at higher Fe(II) surface loadings, the precipitation of magnetite; high Fe(II) levels can also lead to green rust formation, and with high carbonate levels siderite may also be formed. This study expands this emerging conceptual model to a diffusion-dominated system that mimics an idealizedmore » micropore of a ferrihydrite-coated soil aggregate undergoing reduction. Using a novel diffusion cell, coupled with micro-x-ray fluorescence and absorption spectroscopies, we determined that diffusion-controlled gradients in Fe{sup 2+}{sub (aq)} result in a complex array of spatially distributed secondary mineral phases. At the diffusive pore entrance, where Fe{sup 2+} concentrations are highest, green rust and magnetite are the dominant secondary Fe (hydr)oxides (30 mol% Fe each). At intermediate distances from the inlet, green rust is not observed and the proportion of magnetite decreases from approximately 30 to <10%. Across this same transect, the proportion of goethite increases from undetectable up to >50%. At greater distances from the advective-diffusive boundary, goethite is the dominant phase, comprising between 40 and 95% of the Fe. In the presence of magnetite, lepidocrocite forms as a transient-intermediate phase during ferrihydrite-to-goethite conversion; in the absence of magnetite, conversion to goethite is more limited. These experimental observations, coupled with results of reactive transport modeling, confirm the conceptual model and illustrate the potential importance of diffusion-generated concentration

  13. 238U-Series in Fe Oxy/Hydroxides by LA-MC-ICP-MS, New Insights Into Weathering Geochronology

    NASA Astrophysics Data System (ADS)

    Bernal, J.; McCulloch, M.; Eggins, S.; Grun, R.; Eggleton, R.

    2003-12-01

    The establishment of a geochronological framework for weathering processes is essential for an understanding of the evolution of the regolith and its dynamics. However, there are few robust answers regarding the absolute age of weathering and its rates. Nowadays, 40Ar/39Ar analysis of Mn-Oxides (cryptomelane) and K-bearing secondary sulphates have provided one of the few generally reliable chronometers (e.g. 1), but is restricted to high-K secondary phases. This work presents a different approach to obtain geochronological information from weathering minerals, namely measurement of 238U-series disequilibria in authigenic Fe oxy/hydroxides. These may be potentially useful recorders of weathering processes as they commonly occur as weathering products and have high affinity towards dissolved uranyl complexes. Furthermore, U-Th fractionation during weathering has been extensively reported [2], effectively resetting the U/230Th geochronometer. LA-MC-ICP-MS facilitates in situ measurement of 238U-series disequilibria in authigenic microcrystalline iron oxy/hydroxides (precipitated between cracks and veins in partially and heavily weathered chlorite-muscovite schist) and pisoliths (ferruginous concretions). Contrary to previous studies [e.g. 3], in situ measurement of 238U-nuclides enables selective analysis or iron oxy/hydroxides phases, minimizes contributions from allogenic phases and, reduces the need of mathematical corrections to obtain the activity ratios for the authigenic phase [4, 5]. The results suggest that supergene iron oxy/hydroxides are good recorders of weathering processes; they precipitate during the early stages of weathering, reflect the U-isotopic composition of the groundwater, appear to act as closed-systems in weathering conservative environments, and behave in a predictable fashion when subjected to intense weathering and leaching conditions. The 230Th-ages of the iron oxy/hydroxides indicate that the timing and intensity of weathering appears

  14. Incorporation of rare-earth ions in Mg-Al layered double hydroxides: intercalation with an [Eu(EDTA)] - chelate

    NASA Astrophysics Data System (ADS)

    Li, Cang; Wang, Ge; Evans, David G.; Duan, Xue

    2004-12-01

    Reaction of an aqueous slurry of an Mg 2Al-NO 3 layered double hydroxide with a four-fold excess of Na[Eu(EDTA)] gives a material which analyses for Mg 0.68Al 0.32(OH) 2[Eu(EDTA)] 0.10(CO 3) 0.11·0.66H 2O. The interlayer spacing of the material is 13.8 Å, corresponding to a gallery height of 9.0 Å, which accords with the maximal dimensions (9-10 Å) of the anion in metal-EDTA complex salts as determined by single crystal X-ray diffraction. Geometrical considerations show that the charge density on the layered double hydroxide layers is too high to be balanced by intercalation of [Eu(EDTA)] - alone, necessitating the co-intercalation of carbonate ions which have a much higher charge density.

  15. Influence of washing time on residual contamination of carcasses sprayed with lauric acid-potassium hydroxide.

    USDA-ARS?s Scientific Manuscript database

    A series of experiments were conducted to examine reductions in bacterial contamination of broiler carcasses washed for various times in a spray cabinet with a 2% lauric acid (LA)-1% potassium hydroxide (KOH) (w/v) solution. Forty eviscerated carcasses and 5 ceca were obtained from the processing l...

  16. Antimicrobial Activity and Physicochemical Properties of Calcium Hydroxide Pastes Used as Intracanal Medication.

    PubMed

    Zancan, Rafaela Fernandes; Vivan, Rodrigo Ricci; Milanda Lopes, Marcelo Ribeiro; Weckwerth, Paulo Henrique; de Andrade, Flaviana Bombarda; Ponce, José Burgos; Duarte, Marco Antonio Hungaro

    2016-12-01

    The aim of the present study was to evaluate the pH, calcium release, solubility, and antimicrobial action against biofilms of calcium hydroxide + saline solution, Calen (SS White Artigos Dentários Ltd, Rio de Janeiro, Brazil) (CH/P), Calen camphorated paramonochlorophenol (CMCP) (CH/CMPC), and calcium hydroxide + chlorhexidine (CH/CHX) pastes. The pH of the pastes was determined with a calibrated pH meter placed in direct contact with each paste. The root canals of acrylic teeth (N = 10) were filled with the previously mentioned intracanal dressings and immersed in ultrapure water to measure hydroxyl (pH meter) and calcium ion release (atomic absorption spectrophotometer) at time intervals of 3, 7, 15, and 30 days. To assess solubility, the root canals of acrylic teeth (N = 10) were filled with the previously mentioned pastes and scanned by micro-computed tomographic imaging before (initial) and after 7, 15, and 30 days of immersion in ultrapure water. The solubility of each specimen was the difference between the initial and final volume scanning. For antimicrobial analysis, monospecies and dual-species biofilms were in vitro induced on dentin blocks (N = 20). Afterward, they were treated with the pastes for 7 days. Live/dead dye and a confocal microscope were used to measure the percentage of living cells. Data were statistically compared (P < .05). The highest OH - ion release values were found in 3 and 30 days. Ca 2+ releases were greater in CH/CMCP. CH/P and CH/CMCP showed a higher percentage of volume loss values. CH/CHX presented the greatest antimicrobial action. CH/P and CH/CMPC showed higher solubility values in the period analyzed. Seven days of contact may be insufficient for calcium hydroxide + saline solution, CH/P, and CH/CMCP pastes to kill bacterial cells in the biofilms studied. Chlorhexidine added to CH favored greater effectiveness against the previously mentioned bacterial biofilms. Copyright © 2016 American Association of

  17. Tanner and Burbank store lithium hydroxide canisters beneath the MDDK during Expedition 13 / STS-115 Joint Operations

    NASA Image and Video Library

    2006-09-16

    S115-E-06528 (9-21 Sept. 2006) --- Astronauts Joseph R. Tanner (left) and Daniel C. Burbank, both STS-115 mission specialists, work with the lithium hydroxide (LiOH) canisters beneath Space Shuttle Atlantis' middeck.

  18. Evolution of the mechanical and tribological properties of DLC thin films doped with low-concentration hafnium on 316L steel

    NASA Astrophysics Data System (ADS)

    Qi, Meng; Xiao, Jianrong; Gong, Chenyang; Jiang, Aihua; Chen, Yong

    2018-01-01

    Low concentrations (<1 at%) of hafnium doped into diamond-like thin films (Hf-DLC) were deposited on 316L stainless steel and silicon (1 0 0) substrates by magnetron sputtering to attain superior mechanical and tribological properties. Ar and CH4 were used as source gases. The microstructure, chemical composition, and morphology of the Hf-DLC thin films in various concentrations were analyzed using x-ray diffraction, Raman spectroscopy, x-ray photoelectron spectroscopy, scanning electron microscopy and atomic force microscopy. Results showed that Hf species transferred from the particulate microstructure to Hf carbide phases, and the surface roughness increased monotonically with increasing Hf concentration. Moreover, the hardness and elastic modulus exhibited high values when the doped Hf concentration was 0.42 at%. Similarly, the tribological behaviors and wear life of Hf-DLC thin films had a low friction coefficient and excellent wear resistance at 0.42 at% Hf concentration. Therefore, 0.42 at% Hf is an optimal doping concentration to improve the mechanical and tribological properties of DLC thin films. Generally, the use of low-concentration Hf doping into DLC thin films is novel, and the present results provide guidance for the selection of suitable and effective concentration to optimize Hf-DLC thin films with superior performance.

  19. 40 CFR 721.6183 - Amides, from ammonium hydroxide - maleic anhydride polymer and hydrogenated tallow alkyl amines...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... - maleic anhydride polymer and hydrogenated tallow alkyl amines, sodium salts, compds. with ethanolamine... Substances § 721.6183 Amides, from ammonium hydroxide - maleic anhydride polymer and hydrogenated tallow... anhydride polymer and hydrogenated tallow alkyl amines, sodium salts, compds. with ethanolamine (PMN P-00...

  20. 40 CFR 721.6183 - Amides, from ammonium hydroxide - maleic anhydride polymer and hydrogenated tallow alkyl amines...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... - maleic anhydride polymer and hydrogenated tallow alkyl amines, sodium salts, compds. with ethanolamine... Substances § 721.6183 Amides, from ammonium hydroxide - maleic anhydride polymer and hydrogenated tallow... anhydride polymer and hydrogenated tallow alkyl amines, sodium salts, compds. with ethanolamine (PMN P-00...