Note: This page contains sample records for the topic zirconium 97 from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: August 15, 2014.
1

Zirconium  

USGS Publications Warehouse

Zirconium is the 20th most abundant element in the Earth’s crust. It occurs in a variety of rock types and geologic environments but most often in igneous rocks in the form of zircon (ZrSiO4). Zircon is recovered as a coproduct of the mining and processing of heavy mineral sands for the titanium minerals ilmenite and rutile. The sands are formed by the weathering and erosion of rock containing zircon and titanium heavy minerals and their subsequent concentration in sedimentary systems, particularly in coastal environments. A small quantity of zirconium, less than 10 kt/a (11,000 stpy), compared with total world production of 1.4 Mt (1.5 million st) in 2012, was derived from the mineral baddeleyite (ZrO2), produced from a single source in Kovdor, Russia.

Bedinger, G. M.

2013-01-01

2

Systems zirconium-chromium-aluminum and zirconium-copper-aluminum  

Microsoft Academic Search

The systems Zr-Cr-A1 and Zr-Cu-A1 were investigated using alloys prepared in an electric arc furnace with a purified argon atmosphere, by melting starting charges (with allowance for possible losses of volatile components) composed of iodide-grade zirconium (99.9%), electrolytic chromium (99.9%), electrolytic copper (99o99%), and AV-000 aluminum (99.97%). Spot chemical analyses and weight determinations established that the loss of aluminum or

V. Ya. Markiv; V. V. Burnashova

1970-01-01

3

Manage corrosion with zirconium  

SciTech Connect

Zirconium has been used to construct process equipment for over three decades. Zirconium offers low maintenance costs, high reliability, and strong environmental protection with several other advantages: (1) it resists attack by strong acids and caustics, as well as by many salt solutions and molten salts; (2) zirconium has adequate strength for process equipment operating at elevated temperatures; (3) it is relatively low in density, high in thermal conductivity, and low in the coefficient of thermal expansion; (4) zirconium can be fabricated into almost any shape by conventional methods; (5) it is nontoxic and biocompatible; and (6) zirconium does not produce colored ions. The paper looks at some of the major applications of zirconium to better understand its use. The corrosives cited include acetic, formic, nitric, sulfuric, and lactic acids, and phenolic resins.

Yau, T.L.; Bird, K.W.

1995-01-01

4

OXIDATION OF ZIRCONIUM AND ZIRCONIUM ALLOYS  

Microsoft Academic Search

Zirconium oxidation was investigaied in the temperature range 400 io 900 ; deg C at oxygen pressures of 50, 200, and 800 mm. The reaction rate of massive ; (parallelepiped) samples was best expressed by the cubic rate law. At an oxygen ; pressure of 200 mm the activation energy was calculated to be 42.7 kcal per mole, ; and

H. A. Porte; J. G. Schnizlein; R. C. Vogel; D. F. Fischer

1959-01-01

5

Laser ablated zirconium plasma: A source of neutral zirconium  

NASA Astrophysics Data System (ADS)

The authors report spectroscopic investigations of laser produced zirconium (Zr) plasma at moderate laser fluence. At low laser fluence the neutral zirconium species are observed to dominate over the higher species of zirconium. Laser induced fluorescence technique is used to study the velocity distribution of ground state neutral zirconium species. Two-dimensional time-resolved density distributions of ground state zirconium is mapped using planner laser induced fluorescence imaging and total ablated mass of neutral zirconium atoms is estimated. Temporal and spatial evolutions of electron density and temperature are discussed by measuring Stark broadened profile and ratio of intensity of emission lines, respectively.

Yadav, Dheerendra; Thareja, Raj K.

2010-10-01

6

Preparation of zirconium boride  

Microsoft Academic Search

1.It is shown that zirconium boride of the stoichiometric,composition, containing an insignificant amount of impurities, can be produced from commercially-pure starting materials (B4C, ZrO2).2.A study was made of the influence exerted by the chemical composition and particle size of the starting boron carbide on the chemical and phase compositions of the resultant zirconium boride.As in the case of titanium boride

V. F. Funke; S. I. Yudkovskii

1964-01-01

7

Phosphinomethyl complexes of zirconium  

SciTech Connect

The synthesis, structure, and reactivity of a new class of early transition metal complexes containing a phosphinomethyl ligand are described. These complexes possess two different sites of reactivity: the zirconium metal center and the remote phosphine moiety. Phosphinomethyl complexes of zirconium are the first examples of such complexes containing either a group IV or V metal displaying exclusively monohapto bonding between ligand and metal. Zirconcene halides can be selectively mono- or bis-substituted with the appropriate dialkylphosphinomethylithium reagent. The steric and electronic properties of these complexes can be altered by modifying several moieties in the molecule. The intramolecular disposition of the remote functionality can be exploited to stabilize the unusual +3 oxidation state of zirconium. The isolation and characterization of a monomeric paramagnetic phosphinomethyl zirconocene(III) complex has opened the way for a systematic study of the heretofore inaccessible zirconium(III) system. The remote phosphine moiety can also be exploited in an intermolecular manner to construct novel heterobimetallic compounds. These include simple acyclic bridged species as well as a remarkably hindered cyclic complex. Phosphinomethyl complexes of zirconium are unique because they have a remote phosphine moiety which is free to interact in either an inter- or intramolecular fashion. The most important ramifications of this for organic synthesis or catalysis are the stabilization of an unusual monomeric zirconium(III) oxidation state, and the ability to complex a second transition metal to form heterobimetallic complexes.

Young, S.J.

1985-01-01

8

Corrosion of zirconium boride and zirconium boron nitride coated steels  

Microsoft Academic Search

The corrosion behaviour of sputtered zirconium boride and zirconium boron nitride coatings on carbon steel substrates was investigated. Coatings were produced employing non-reactive as well as reactive d.c. magnetron sputtering deposition using zirconium diboride targets. The copper decoration technique was used to make visible the types of coating defects and their distribution. To quantify the corrosion behaviour, potentiodynamic polarization measurements

M. Ürgen; A. F. Çakir; O. L. Eryilmaz; C. Mitterer

1995-01-01

9

Zirconium diboride low resistance layers  

Microsoft Academic Search

The ion-plasma sputtering method, as we see it, is perspective for the zirconium diboride thin films production. The literature sources on the zirconium diboride thin films growth characteristics are sparse. The goal of this paper is to investigate the possibility of the zirconium diboride thin films production with the magnetron sputtering method and to investigate its structure and physical properties

A. F. Andreeva; V. M. Statsenko; L. A. Klotchkov

1997-01-01

10

Zirconium in the nuclear industry  

SciTech Connect

This book contains over 40 selections. Some of the titles are: Zirconium-Barrier Cladding Attributes; Recent Studies of Crack Initiation During Stress Corrosion Cracking of Zirconium Alloys; Oxidation of Zircaloy-4 in Steam at 1300 to 2400/sup 0/C; and Residual Stresses in Textured Zirconium Alloys.

Adamson, R.B.; Van Swam, L.F.P.

1987-01-01

11

Dibarium zirconium tetraoxalate trihydrate.  

PubMed

A new mixed barium zirconium oxalate, triaquatetra-mu-oxalato-dibarium(II)zirconium(IV), Ba(2)Zr(C(2)O(4))(4).3H(2)O or [Ba(2)Zr(C(2)O(4))(4)(H(2)O)(3)](n), has been synthesized. The complex is built from eightfold-coordinated Zr atoms and eleven- and sixfold-coordinated Ba atoms, linked by oxalate groups. The Zr atom, the two Ba atoms and one water O atom lie on crystallographic twofold axes, so that each coordination polyhedron has imposed C2 symmetry. Packing in the crystal is also assumed through hydrogen bonds. PMID:15178833

Vertruyen, Bénédicte; Robertz, Bénédicte; Guillaume, Bernard; Rulmont, André; Spirlet, Marie Rose

2004-06-01

12

Electroless deposition process for zirconium and zirconium alloys  

DOEpatents

A method is disclosed for preventing stress corrosion cracking or metal embrittlement of a zirconium or zirconium alloy container that is to be coated on the inside surface with a layer of a metal such as copper, a copper alloy, nickel, or iron and used for holding nuclear fuel material as a nuclear fuel element. The zirconium material is etched in an etchant solution, desmutted mechanically or ultrasonically, oxidized to form an oxide coating on the zirconium, cleaned in an aqueous alkaline cleaning solution, activated for electroless deposition of a metal layer and contacted with an electroless metal plating solution. This method provides a boundary layer of zirconium oxide between the zirconium container and the metal layer. 1 fig.

Donaghy, R.E.; Sherman, A.H.

1981-08-18

13

Electroless deposition process for zirconium and zirconium alloys  

DOEpatents

A method is disclosed for preventing stress corrosion cracking or metal embrittlement of a zirconium or zirconium alloy container that is to be coated on the inside surface with a layer of a metal such as copper, a copper alloy, nickel, or iron and used for holding nuclear fuel material as a nuclear fuel element. The zirconium material is etched in an etchant solution, desmutted mechanically or ultrasonically, oxidized to form an oxide coating on the zirconium, cleaned in an aqueous alkaline cleaning solution, activated for electroless deposition of a metal layer and contacted with an electroless metal plating solution. This method provides a boundary layer of zirconium oxide between the zirconium container and the metal layer.

Donaghy, Robert E. (Wilmington, NC); Sherman, Anna H. (Wilmington, NC)

1981-01-01

14

Plasma arc melting of zirconium  

SciTech Connect

Zirconium, like some other refractory metals, has an undesirable sensitivity to interstitials such as oxygen. Traditionally, zirconium is processed by electron beam melting to maintain minimum interstitial contamination. Electron beam melted zirconium, however, does not respond positively to mechanical processing due to its large grain size. The authors undertook a study to determine if plasma arc melting (PAM) technology could be utilized to maintain low interstitial concentrations and improve the response of zirconium to subsequent mechanical processing. The PAM process enabled them to control and maintain low interstitial levels of oxygen and carbon, produce a more favorable grain structure, and with supplementary off-gassing, improve the response to mechanical forming.

Tubesing, P.K.; Korzekwa, D.R.; Dunn, P.S.

1997-12-31

15

Zirconium for superior corrosion resistance  

SciTech Connect

Zirconium is a transition element located along with sister elements titanium and hafnium in Group IVB of the periodic table. It is grayish white metal, with a density somewhat less than carbon steel. Zirconium is the ninth most common metallic element in the earth`s crust, and is more abundant than zinc, lead, nickel, or even copper. Zirconium is exceptionally resistant to corrosion by many common acids and alkalis. It is resistant to most organic acids, such as formic, acetic, lactic, and oxalic acids. It also has a high resistance to localized forms of corrosion, such as pitting, crevice corrosion, and stress corrosion cracking. Its corrosion resistance is caused by the formation of a dense, tenaciously adherent, chemically inert oxide film on the surface. This oxide film protects the base metal from both chemical and mechanical attack at temperatures up to about 400 C (750 F). This article describes zirconium`s formability, machinability, corrosion resistance, and several typical applications.

Bird, K.W. [SPF Corp. of America, Louisville, CO (United States); Richardson, K. [Wah Chang, Albany, OR (United States)

1997-03-01

16

PREPARATION OF PURE ANHYDROUS ZIRCONIUM FLUORIDE  

Microsoft Academic Search

The preparation of pure and anhydrous (with hafnium) zirconium fluoride ; was studied on a laboratory scale. The starting material was zirconium oxide. ; Ammonium acid fluoride was used as the fluorinating agent. Ammonium ; fluozirconate was transformed to zirconium fluoride by heating in a vacuum. The ; zirconium fluoride was purified by sublimation at 700 deg in a vacuum.

C. Decroly; D. Tytgat; J. Gerard

1957-01-01

17

Preparation of zirconium diboride  

Microsoft Academic Search

1.X-ray and microstructural analyses show that zirconium diboride powder obtained in industrial plants by boron carbide reduction in hydrogen at 1800°C contains about 4.94±0.12% ZrB12.2.A uniphase product (ZrB2) can be obtained by boron carbide reduction below 1650°, which is the lower limit of temperature stability of ZrB12 [16], or at higher temperatures, followed by slow cooling in the range 1650–1400°C.3.The

M. A. Kuzenkova; P. S. Kislyi

1965-01-01

18

Method of Etching Zirconium Diboride.  

National Technical Information Service (NTIS)

The invention described herein may be manufactured, used, and licensed by or for the Government for governmental purposes without the payment to us of any royalty thereon. This invention relates in general to a method of etching zirconium diboride, zircon...

L. S. Heath B. Kwiatkowski

1988-01-01

19

Method for Collecting Zirconium Tetrachloride.  

National Technical Information Service (NTIS)

A neutron-irradiated nuclear fuel composition containing zirconium and a nuclear fuel selected from uranium and plutonium is treated by hydrochlorination of the composition with gaseous hydrogen chloride at from 350 to 800 degrees C. to selectively volati...

T. A. Gens

1965-01-01

20

Environmentally Friendly Zirconium Oxide Pretreatment.  

National Technical Information Service (NTIS)

Pretreatments based on zirconium oxide are being used commercially in automotive and other industrial operations as replacements to hexavalent chromium-based and zinc phosphate pretreatments. This report describes work to document the performance of comme...

J. L. Stalker N. J. Silvernail T. Lingenfelter

2013-01-01

21

Comminution characteristics of zirconium diboride  

Microsoft Academic Search

1.The investigation into the comminution kinetics of zirconium diboride powder has demonstrated that comminution is more effective in a vibratory mill than in a ball mill. The optimum comminution time is 2–3 h.2.Tsyurupa's analytical method of calculation can be employed for determining the particle-size distribution of powders.3.Of the dispersing media investigated, ethyl alcohol gives the most agglomeration-resistant zirconium diboride suspensions.4.Of

L. V. D'yakonova; P. S. Kislyi

1972-01-01

22

Spectrophotometric Determination of Zirconium with Xylenol Orange.  

National Technical Information Service (NTIS)

High purity hydride forming metal films are used as hydrogen isotope occluders and function as electrodes in neutron generator tubes. This use of zirconium occluder films requires reliable analytical methods for routine determination of the zirconium film...

R. J. Antepenko

1982-01-01

23

Ablation Resistant Zirconium and Hafnium Ceramics  

NASA Technical Reports Server (NTRS)

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.

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

1998-01-01

24

Dissolution of Zirconium in Titanium Equipment.  

National Technical Information Service (NTIS)

The method of dissolving zirconium salts in a titanium container system is useful in the nuclear reactor field. The zirconium is reacted with zirconium dissolvent consisting of a 2 to 6 molar aqueous solution of nitric acid containing total fluoride not e...

W. E. Clark T. A. Gens

1965-01-01

25

Nanolithography on Zirconium Surfaces  

NASA Astrophysics Data System (ADS)

We report, for the first time, scanning probe nanolithography on single crystal zirconium (Zr) surfaces using an atomic force microscope (AFM) tip in air. Preliminary experiments indicate that the size of the nanostructures written on Zr is 50 - 100 nm with applied DC voltages of 1 - 25 V and exposure times in the range of 1 - 60 seconds. We study the dependence of the size of the nanostructures on the magnitude of the applied voltage and current through the Zr substrate. This allows us to compare the results of SPM lithography on Zr with those on Si. Apparently, the nature of the current in these two cases is different. The current during high voltage Si oxidation exhibits Ohmic behavior and can reach 300 microamps. We believe that this current is the result of electrical breakdown in the meniscus of water resulting in conductivity dominated by electron mobility. In the case of Zr, the magnitude of the DC current is very small (less than 1 microamp) and exhibits typical Faradic behavior related with the transport of hydroxyl ions from an AFM tip down to the Zr surface. Lithographic oxidation of Zr surfaces is a very promising step toward the development of a comprehensive description of the nanolithographic process and complements our efforts to prepare Zr surfaces with novel properties via hyperthermal chemical reaction pathways.

Farkas, Natalia; Lyuksyutov, Sergei F.; Ramsier, Rex D.

2002-04-01

26

Transformation superplasticity of zirconium  

SciTech Connect

A tensile strain of 270% was achieved for coarse-grained zirconium subjected to transformation superplasticity condition, where strain increments are accumulated upon repeated thermal cycling around the allotropic transformation temperature under the biasing effect of a uniaxial tensile stress. The strain increment per cycle was found to consist of two equal contributions from transformations on heating and cooling and to increase linearly with the applied stress. The measured strain increments are in good quantitative agreement with predictions based on the average internal stress during the transformation, which was determined independently from experimental transformation times. As the cycling frequency is raised, the average strain rate increases (a maximum value of 1.3 {times} 10{sup {minus}4} s{sup {minus}1} was measured), but the strain increment per cycle decreases above a critical cycling frequency, for which the sample gage section undergoes only a partial phase transformation. The resulting reduction in internal mismatch and increase in internal stress are modeled using the experimental observation that {beta}-Zr deforms by a mixture of diffusional and dislocation creep in the stress range of interest.

Zwigl, P. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Materials Science and Engineering; Dunand, D.C. [Northwestern Univ., Evanston, IL (United States). Dept. of Materials Science and Engineering

1998-10-01

27

Mössbauer spectroscopy of zirconium alloys  

NASA Astrophysics Data System (ADS)

Mössbauer investigations of zirconium alloys were examined. Data about the chemical state of iron atoms in the zirconium alloys of different composition has been provided. Mössbauer spectroscopy revealed that small quantities of iron in binary zirconium alloy are in the solid solution ?-Zr (up to 0.02 wt.%). Different iron atoms concentration and thermo-mechanical treatments may lead to formation the intermetallic compounds Zr3Fe, Zr2Fe, ZrFe2. Adding tin atoms does not affect the formation and shape of Mössbauer spectra of these compounds. Adding Cr and Nb atoms makes significant changes in the shape of Mössbauer spectra and leads to the formation of complex intermetallic compounds. Adding Cu and W atoms, the shape of the binary alloys spectra (Zr-Fe) remains unchanged, but a change in the temperature dependence behavior of the spectral parameters occurs and also, changes to the properties of the alloys.

Filippov, V. P.; Bateev, A. B.; Lauer, Yu. A.; Kargin, N. I.

2013-04-01

28

Eutectic structure in zirconium electrocorundum  

SciTech Connect

The authors explain the eutectic structure of zirconium electrocorundum, with the goal of controlling crystallization of actual alloys by changing the melt cooling conditions to produce materials of assigned properties. Sample chemical composition and conditions of preparation are shown. A qualitative change in structure of hypoeutectic alloys of Al/sub 2/O/sub 3/ with zRO/sub 2/ (zirconium electrocorundum) is possible only under conditions where the formation mechanism of corundum crystals changes, and the fresh branched growth of crystals composing the eutectic is disrupted. Nucleation of a regular eutetic struscure in zirconium electrocorundum is observed for the case of melt crystallization far from eutectic composition on abrupt melt cooling at the mold boundary and for the case of low-frequency melt vibration.

Zhekhanova, N.B.; Fotiev, A.A.; Gladkov, V.E.

1986-09-01

29

Reactive hot pressing of zirconium diboride  

Microsoft Academic Search

The reaction of zirconium and boron was investigated as a potential route to form dense monolithic zirconium diboride (ZrB2) ceramics. Attrition milling of the precursors produced nanosized (less than 100nm) zirconium metal particles that reacted with boron to form ZrB2 with an average particle size of less than 100nm at temperatures as low as 600°C. Scanning electron microscopy of ZrB2

Adam L. Chamberlain; William G. Fahrenholtz; Gregory E. Hilmas

2009-01-01

30

Spectrophotometric titration of zirconium in siliceous materials.  

PubMed

An accurate and selective complexometric titration procedure based upon a spectrophotometrically detected end-point has been developed for the determination of zirconium in glasses, glass-ceramics and refractories. A p-bromomandelic acid separation step for zirconium imparts excellent selectivity to the procedure. The method is particularly important for the 1-5% concentration range where a simple, accurate and selective method for the determination of zirconium has been lacking. PMID:18962344

Sugawara, K F; Su, Y S; Strzegowski, W R

31

Spectrophotometric determination of zirconium with xylenol orange  

SciTech Connect

High purity hydride forming metal films are used as hydrogen isotope occluders and function as electrodes in neutron generator tubes. This use of zirconium occluder films requires reliable analytical methods for routine determination of the zirconium film weight in a production environment. In this study, a spectrophotometric method was evaluated for the determination of zirconium films. The method is based upon the formation of a highly colored zirconium complex with xylenol orange in a dilute perchloric acid medium. Dilute hydrofluoric acid is used in this procedure to selectively dissolve the zirconium film off the substrate. A perchloric acid fuming step is used to remove hydrofluoric acid from the solution. The zirconium solutions are depolymerized before complex formation by heating in 2 N perchloric acid. The zirconium complex exhibits a maximum absorbance in 0.2 to 0.3 M perchloric acid at a wavelength of 531 nanometers. Beer's law is obeyed for zirconium concentrations through 2.1 parts per million. Molybdenum, at concentrations equal to zirconium, does not interfere with the xylenol orange method.

Antepenko, R.J.

1982-05-14

32

Zirconium in a sulfuric acid pickling application  

SciTech Connect

In 1972, Goodyear discovered that zirconium was an ideal material to construct heating coils for sulfuric acid picking tanks. Recently, localized corrosion and high uniform corrosion were reported with certain zirconium coils. The problems could be attributed to the contamination of chloride and/or fluoride ions. Results of electrochemical and immersion tests are used to discuss the effects of acid concentration and acid impurities, such as iron, chloride and fluoride ions, on zirconium's corrosion properties in H/sub 2/SO/sub 4/. Possible sources for acid impurities are identified. Recommendations are made for steel picking when zirconium equipment is used.

Yau, T.L.

1988-01-01

33

Bacterial adhesion to zirconium surfaces  

Microsoft Academic Search

Zirconium alloys are well-known for their resistance to harsh chemical environments. In the interest of assessing the potential of this class of materials for bio-implant applications, we need to determine if this environmental stability transfers to biological systems. We report on our use of viable counts and infrared spectroscopic techniques to monitor how well thermally processed Zircaloy-2 surfaces resist bacterial

B. W. Buczynski; M. M. Kory; R. P. Steiner; T. A. Kittinger; R. D. Ramsier

2003-01-01

34

Optical properties of zirconium nitride  

SciTech Connect

In this investigation the authors have studied the optical properties of zirconium nitride by the Beattie-Cohn ellipsometric method. The optical properties were studied on an ellipsometric unit over the spectral range 1 eV < E < 5 eV. The dependence of the reflectivity coefficient, the light transmittance, and the real part of the dielectric function were calculated from the results of measuring the optical constants n and kappa as a function of the photon energy.

Atamanenko, B.A.; Belyi, M.U.; Drozd, P.I.; Tsebulya, G.G.; Shaikevich, I.A.

1987-11-01

35

COMPOSITION OF ZIRCONIUM AND HAFNIUM CUPFERRONATES  

Microsoft Academic Search

The composition of Zr and Hf cupferronates prepared at various acidtties ; and aging times was analyzed. Cup ferronate reactions with Zr\\/sup 4+\\/ or strong ; complexes of zirconium fluoride, sulfate, or nitrate precipitate into ; concentration on zirconium or hafnium cupferronate composition was studied. In ; weakly acid solutions both Hf and Zr form variable composition cupferronates. ; (R.V.L.);

K. F. Karlysheva; I. A. Sheka

1962-01-01

36

47 CFR 97.217 - Telemetry.  

Code of Federal Regulations, 2010 CFR

...Telecommunication 5 2009-10-01 2009-10-01 false Telemetry. 97.217 Section 97.217 Telecommunication...RADIO SERVICE Special Operations § 97.217 Telemetry. Telemetry transmitted by an amateur station on or...

2009-10-01

37

47 CFR 97.217 - Telemetry.  

Code of Federal Regulations, 2010 CFR

...Telecommunication 5 2010-10-01 2010-10-01 false Telemetry. 97.217 Section 97.217 Telecommunication...RADIO SERVICE Special Operations § 97.217 Telemetry. Telemetry transmitted by an amateur station on or...

2010-10-01

38

47 CFR 97.111 - Authorized transmissions.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 false Authorized transmissions. 97.111 Section 97.111 ...Standards § 97.111 Authorized transmissions. (a) An amateur station may...of two-way communications: (1) Transmissions necessary to exchange...

2013-10-01

39

Electrochemical decomposition of complexes of zirconium or hafnium  

Microsoft Academic Search

This patent describes an improvement in a method for separating hafnium from zirconium where a complex of zirconium and hafnium chlorides and phosphorus oxychloride is prepared from zirconium-hafnium chloride and the complex is subjected to a distillation to produce a hafnium chloride enriched stream of complex and a zirconium enriched chloride stream of complex. The improvement comprising: electrochemical breaking the

T. S. Snyder; R. A. Stoltz; D. F. McLaughlin

1989-01-01

40

Hydrogen desorption kinetics from zirconium hydride and zirconium metal in vacuum  

NASA Astrophysics Data System (ADS)

The kinetics of hydrogen desorption from zirconium hydride is important in many nuclear design and safety applications. In this paper, a coordinated experimental and modeling study has been used to explicitly demonstrate the applicability of existing kinetic theories for hydrogen desorption from zirconium hydride and ?-zirconium. A static synthesis method was used to produce ?-zirconium hydride, and the crystallographic phases of the zirconium hydride were confirmed by X-ray diffraction (XRD). Three obvious stages, involving ?-zirconium hydride, a two-phase region, and ?-zirconium, were observed in the hydrogen desorption spectra of two zirconium hydride specimens with H/Zr ratios of 1.62 and 1.64, respectively, which were obtained using thermal desorption spectroscopy (TDS). A continuous, one-dimensional, two-phase moving boundary model, coupled with the zero- and second-order kinetics of hydrogen desorption from ?-zirconium hydride and ?-zirconium, respectively, has been developed to reproduce the TDS experimental results. A comparison of the modeling predictions with the experimental results indicates that a zero-order kinetic model is valid for description of hydrogen flux away from the ?-hydride phase, and that a second-order kinetic model works well for hydrogen desorption from ?-Zr if the activation energy of desorption is optimized to be 70% of the value reported in the literature.

Hu, Xunxiang; Terrani, Kurt A.; Wirth, Brian D.

2014-05-01

41

Crystal structure of potassium titanyl phosphate doped with zirconium  

SciTech Connect

This paper reports on the results of precision X-ray structural investigations of single crystals of the compounds KTi{sub 0.96}Zr{sub 0.04}OPO{sub 4} (at 293 K) and KTi{sub 0.97}Zr{sub 0.03}OPO{sub 4} (at 293 and 105 K). No significant splitting of the positions occupied by potassium atoms is revealed. This result is in agreement with a considerable decrease in the electrical conductivity of potassium titanyl phosphate KTiOPO{sub 4} (KTP) crystals doped with zirconium (KTP: Zr) as compared to crystals of undoped potassium titanyl phosphate. It is established that the difference between the Ti-O bond lengths in chains formed by titanium octahedra is not a single structural parameter responsible for the nonlinear optical properties of crystals in this series.

Alekseeva, O. A., E-mail: olalex@ns.crys.ras.ru; Dudka, A. P.; Sorokina, N. I. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Pietraszko, A. [Polish Academy of Sciences, Institute of Low Temperature and Structure Research (Poland); Rabadanov, M. Kh. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Agapova, E. I.; Voronkova, V. I. [Lomonosov Moscow State University (Russian Federation); Simonov, V. I. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

2007-07-15

42

Method of etching zirconium diboride  

SciTech Connect

The invention described herein may be manufactured, used, and licensed by or for the Government for governmental purposes without the payment to us of any royalty thereon. This invention relates in general to a method of etching, zirconium diboride(ZrB/sub 2/) and, in particular, to a method of dry etching a thin film of ZrB/sub 2/ that has been deposited onto a substrate and patterned using photolithography. U.S. patent application S.N. 156, 124, filed 16 February, 1988, of Linda S. Heath for Method of Etching Titanium Diboride and assigned to a common assignee and with which this application is copending describes and claims a method of etching titanium diboride with a dry etch. Zirconium diboride, like titanium diboride, TiB/sub 2/, has become of interest in laboratory research because of its resistance to change or degradation at high temperatures. By adjusting the process parameters, one is able to attain etch rates of 67 to 140 A/min for ZrB/sub 2/. This is useful for patterning ZrB/sub 2/ as a diffusion barrier or a Schottky contact to semiconductors. The ZrB/sub 2/ film may be on a GaAs substrate.

Heath, L.S.; Kwiatkowski, B.

1988-03-31

43

Synthesis of zirconium diboride–zirconium nitride composite powders by self-propagating high-temperature synthesis  

Microsoft Academic Search

Formation of zirconium diboride–zirconium nitride composite powders by self propagating high temperature reaction of zirconium,\\u000a boron and hexagonal boron nitride powders was investigated. Zirconium diboride–zirconium nitride powder mixtures with varying\\u000a proportions were produced by changing the amount of boron nitride in the reactants. Products were subjected to powder X-ray\\u000a diffraction analysis; and grain size and morphology was examined by scanning

H. E. Çamurlu; F. Maglia

2007-01-01

44

Preparation of technical zirconium diboride by the carbothermic reduction of mixtures of zirconium and boron oxides  

Microsoft Academic Search

A study was made of the preparation of technical zirconium diboride by the reduction of mixtures of zirconium and boron oxides with carbon under industrial conditions. It is shown that the optimum conditions for the preparation of zirconium diboride by the carbothermic method are established when a charge having the composition ZrO2+1.2 B2O3+5 C (i.e., with a 20% excess of

A. I. Karasev

1973-01-01

45

Penta-zirconium copper tribismuth.  

PubMed

Penta-zirconium copper tribismuth, Zr5CuBi3, crystallizes in the hexa-gonal Hf5CuSn3 structure type. The asymmetric unit contains two Zr sites (site symmetries 3.2 and m2m), one Cu site (site symmetry 3.m) and one Bi site (site symmetry m2m). The environment of the Bi atoms is a tetra-gonal anti-prism with one added atom and a coordination number (CN) of 9. The polyhedron around the Zr1 atom is a defective cubo-octa-hedron with CN = 11. The bicapped hexa-gonal anti-prism (CN = 14) is typical for Zr2 atoms. The Cu atom is enclosed in a eight-vertex polyhedron (octa-hedron with two centered faces). The metallic type of bonding was indicated by an analysis of the inter-atomic distances and electronic structure calculation data. PMID:24109256

Balinska, Agnieszka; Tarasiuk, Ivan; Pavlyuk, Volodymyr

2013-01-01

46

Penta-zirconium copper tribismuth  

PubMed Central

Penta­zirconium copper tribismuth, Zr5CuBi3, crystallizes in the hexa­gonal Hf5CuSn3 structure type. The asymmetric unit contains two Zr sites (site symmetries 3.2 and m2m), one Cu site (site symmetry 3.m) and one Bi site (site symmetry m2m). The environment of the Bi atoms is a tetra­gonal anti­prism with one added atom and a coordination number (CN) of 9. The polyhedron around the Zr1 atom is a defective cubo­octa­hedron with CN = 11. The bicapped hexa­gonal anti­prism (CN = 14) is typical for Zr2 atoms. The Cu atom is enclosed in a eight-vertex polyhedron (octa­hedron with two centered faces). The metallic type of bonding was indicated by an analysis of the inter­atomic distances and electronic structure calculation data.

Balinska, Agnieszka; Tarasiuk, Ivan; Pavlyuk, Volodymyr

2013-01-01

47

Ageing of zirconium alloy components  

NASA Astrophysics Data System (ADS)

India has two types (pressurized heavy water reactors (PHWRs) and boiling water reactors (BWRs)) of commercial nuclear reactors in operation, in addition to research reactors. Many of the life limiting critical components in these reactors are fabricated from zirconium alloys. The progressive degradation of these components caused by the cumulative exposure of high energy neutron irradiation with increasing period of reactor operation was monitored to assess the degree of ageing. The components/specimens examined included fuel element claddings removed from BWRs, pressure tubes and garter springs removed from PHWRs and calandria tube specimens used in PHWRs. The tests included tension test (for cladding, garter spring), fracture toughness test (for pressure tube), crush test (for garter spring), and measurement of irradiation induced growth (for calandria tube). Results of various tests conducted are presented and applications of the test results are elaborated for residual life estimation/life extension of the components.

Chatterjee, S.; Shah, Priti Kotak; Dubey, J. S.

2008-12-01

48

Structure characteristics of disordered zirconium hydroxoxides  

Microsoft Academic Search

The structural characteristics of low-temperature zirconium hydroxoxide and zirconium dioxide obtained from zirconyl nitrate\\u000a and treated at 383 and 653 K have been studied by the X-ray method of distribution of radial electron density. It is shown\\u000a that the low-temperature hydroxide contains a ?10 to 15-? nucleus of the crystalline phase with a structure of short-range\\u000a order similar to the

D. A. Zyuzin; E. M. Moroz; A. S. Ivanova; A. N. Shmakov

2003-01-01

49

Resistance Butt Welding of Zirconium Alloy Material  

Microsoft Academic Search

Zirconium alloy is the main structural material used in the nuclear fuel production. This material has distinct advantages like less thermal neutron absorption cross-section and better chemical and mechanical properties for the reactor-working conditions. This material is widely used in boiling water and heavy water type reactors. Natural Uranium Dioxide (UO2) pellets are loaded into thin wall zirconium alloy tubes

D. S. Setty; Reddy P. Ravinder; A. L. N. Murthy

2008-01-01

50

Electrochemical decomposition of complexes of zirconium or hafnium  

SciTech Connect

This patent describes an improvement in a method for separating hafnium from zirconium where a complex of zirconium and hafnium chlorides and phosphorus oxychloride is prepared from zirconium-hafnium chloride and the complex is subjected to a distillation to produce a hafnium chloride enriched stream of complex and a zirconium enriched chloride stream of complex. The improvement comprising: electrochemical breaking the zirconium or hafnium chloride complex from the distillation in a chloride or fluoride and chloride molten salt bath to produce the metal or a chloride oof zirconium or hafnium.

Snyder, T.S.; Stoltz, R.A.; McLaughlin, D.F.

1989-09-12

51

Investigation of a Cell Design for Electrowinning Zirconium Metal from Zirconium Tetrachloride.  

National Technical Information Service (NTIS)

A cell concept adaptable to the large-scale electrowinning of zirconium metal from zirconium tetrachloride was investigated. Tests were made in twin cells, each 12-in-diam by 33-in long. Electrowinning was performed in one chamber from which the electroly...

G. M. Martinez D. E. Shanks J. R. Woodyard M. M. Wong

1976-01-01

52

Science and Engineering Degrees: 1966-97  

NSF Publications Database

... Degrees: 1966-97 Detailed Statistical Tables Hypertext Format Science and Engineering Degrees ... Format (.pdf) Science and Engineering Degrees: 1966-97 This report is available in hypertext (.htm ...

53

ZIRCONIUM OXIDE NANOSTRUCTURES PREPARED BY ANODIC OXIDATION  

SciTech Connect

Zirconium oxide is an advanced ceramic material highly useful for structural and electrical applications because of its high strength, fracture toughness, chemical and thermal stability, and biocompatibility. If highly-ordered porous zirconium oxide membranes can be successfully formed, this will expand its real-world applications, such as further enhancing solid-oxide fuel cell technology. Recent studies have achieved various morphologies of porous zirconium oxide via anodization, but they have yet to create a porous layer where nanoholes are formed in a highly ordered array. In this study, electrochemical methods were used for zirconium oxide synthesis due to its advantages over other coating techniques, and because the thickness and morphology of the ceramic fi lms can be easily tuned by the electrochemical parameters, such as electrolyte solutions and processing conditions, such as pH, voltage, and duration. The effects of additional steps such as pre-annealing and post-annealing were also examined. Results demonstrate the formation of anodic porous zirconium oxide with diverse morphologies, such as sponge-like layers, porous arrays with nanoholes ranging from 40 to 75 nm, and nanotube layers. X-ray powder diffraction analysis indicates a cubic crystallographic structure in the zirconium oxide. It was noted that increased voltage improved the ability of the membrane to stay adhered to the zirconium substrate, whereas lower voltages caused a propensity for the oxide fi lm to fl ake off. Further studies are needed to defi ne the parameters windows that create these morphologies and to investigate other important characteristics such as ionic conductivity.

Dang, Y. Y.; Bhuiyan, M.S.; Paranthaman, M. P.

2008-01-01

54

47 CFR 97.503 - Element standards.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Element standards. 97.503 Section 97...Qualifying Examination Systems § 97.503 Element standards. A written examination...of a question set as follows: (a) Element 2: 35 questions concerning the...

2013-10-01

55

47 CFR 97.505 - Element credit.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Element credit. 97.505 Section 97.505...Qualifying Examination Systems § 97.505 Element credit. (a) The administering...Advanced Class operator license grant: Elements 2 and 3. (2) An unexpired...

2013-10-01

56

29 CFR 97.34 - Copyrights.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Copyrights. 97.34 Section 97.34 Labor...Property, and Subawards § 97.34 Copyrights. The Federal awarding agency...Federal Government purposes: (a) The copyright in any work developed under a...

2013-07-01

57

47 CFR 97.113 - Prohibited transmissions.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 false Prohibited transmissions. 97.113 Section 97.113 ...Standards § 97.113 Prohibited transmissions. (a) No amateur station shall...least 30 days in advance of the actual transmissions; and where the control operator...

2013-10-01

58

40 CFR 97.627 - Account error.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Account error. 97.627 Section 97.627 Protection...Trading Program § 97.627 Account error. The Administrator may, at his or...and on his or her own motion, correct any error in any Allowance Management System...

2013-07-01

59

40 CFR 97.356 - Account error.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Account error. 97.356 Section 97.356 Protection...Tracking System § 97.356 Account error. The Administrator may, at his or...and on his or her own motion, correct any error in any CAIR NOX Ozone Season...

2013-07-01

60

40 CFR 97.527 - Account error.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Account error. 97.527 Section 97.527 Protection...Trading Program § 97.527 Account error. The Administrator may, at his or...and on his or her own motion, correct any error in any Allowance Management System...

2013-07-01

61

40 CFR 97.156 - Account error.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Account error. 97.156 Section 97.156 Protection...Tracking System § 97.156 Account error. The Administrator may, at his or...and on his or her own motion, correct any error in any CAIR NOX Allowance Tracking...

2013-07-01

62

40 CFR 97.727 - Account error.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Account error. 97.727 Section 97.727 Protection...Trading Program § 97.727 Account error. The Administrator may, at his or...and on his or her own motion, correct any error in any Allowance Management System...

2013-07-01

63

40 CFR 97.427 - Account error.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Account error. 97.427 Section 97.427 Protection...Trading Program § 97.427 Account error. The Administrator may, at his or...and on his or her own motion, correct any error in any Allowance Management System...

2013-07-01

64

40 CFR 97.256 - Account error.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Account error. 97.256 Section 97.256 Protection...Tracking System § 97.256 Account error. The Administrator may, at his or...and on his or her own motion, correct any error in any CAIR SO2 Allowance Tracking...

2013-07-01

65

40 CFR 97.56 - Account error.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Account error. 97.56 Section 97.56 Protection...Allowance Tracking System § 97.56 Account error. The Administrator may, at his or...and on his or her own motion, correct any error in any NOX Allowance Tracking...

2013-07-01

66

40 CFR 721.10250 - Zirconium lysine complex (generic).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Zirconium lysine complex (generic). 721.10250 ...Substances § 721.10250 Zirconium lysine complex (generic). (a) Chemical...substance identified generically as zirconium lysine complex (PMN P-09-356) is...

2013-07-01

67

Processing fissile material mixtures containing zirconium and/or carbon  

DOEpatents

A method of processing spent TRIZO-coated nuclear fuel may include adding fluoride to complex zirconium present in a dissolved TRIZO-coated fuel. Complexing the zirconium with fluoride may reduce or eliminate the potential for zirconium to interfere with the extraction of uranium and/or transuranics from fission materials in the spent nuclear fuel.

Johnson, Michael Ernest; Maloney, Martin David

2013-07-02

68

Zirconium: biomedical and nephrological applications.  

PubMed

Recent years have witnessed a rapid increase in the use of zirconium (Zr)-containing compounds in artificial internal organs. Examples include dental implants and other restorative practices, total knee and hip replacement, and middle-ear ossicular chain reconstruction. In nephrological practice, Zr-containing sorbents have been used in hemofiltration, hemodialysis, peritoneal dialysis, and in the design and construction of wearable artificial kidneys. Zr compounds continue to be widely and extensively used in deodorant and antiperspirant preparations. In the public health arena, Zr compounds have been studied or used in controlling phosphorus pollution and in the reclamation of poison and bacteria-contaminated water. Experimental and clinical studies support the general consensus that Zr compounds are biocompatible and exhibit low toxicity. Reports on possible Zr-associated adverse reactions are rare and, in general, have not rigorously established a cause-and-effect relationship. Although publications on the use of Zr compounds have continued to increase in recent years, reports on Zr toxicity have virtually disappeared from the medical literature. Nevertheless, familiarity with, and continued vigilant monitoring of, the use of these compounds are warranted. This article provides an updated review on the biomedical use of Zr compounds. PMID:21245802

Lee, David B N; Roberts, Martin; Bluchel, Christian G; Odell, Ross A

2010-01-01

69

Review of zirconium-zircaloy pyrophoricity  

SciTech Connect

Massive zirconium metal scrap can be handled, shipped, and stored with no evidence of combustion or pyrophoricity hazards. Mechanically produced fine scrap such as shavings, turnings, or powders can burn but are not pyrophoric unless the particle diameter is less than 54 ..mu..m. Powders with particle diameters less than 54 ..mu..m can be both pyrophoric and explosive. Pyrophoric powders should be collected and stored underwater or under inert gas cover to reduce the flammability hazard. Opening sealed containers of zirconium stored underwater should be attempted with caution since hydrogen may be present. The factors that influence the ignition temperature have been explored in depth and recommendations are included for the safe handling, shipping, and storage of pyrophoric or flammable zirconium. 29 refs., 5 figs., 6 tabs.

Cooper, T.D.

1984-11-01

70

Radiation effects on corrosion of zirconium alloys  

SciTech Connect

From the wide use of zirconium alloys as components in nuclear reactors, has come clear evidence that reactor radiation is a major corrosion parameter. The evidence emerges from comparisons of zirconium alloy corrosion behavior in different reactor types, for example, BWRs versus PWRs and in corresponding reactor loop chemistries; also, oxidation rates differ with location along components such as fuel rods and reactor pressure tubes. In most respects, oxidation effects on power reactor components are paralleled by oxidation behavior on specimens exposed to radiation in reactor loops.

Johnson, A.B. Jr.

1989-06-01

71

Effect of zirconium carbide and carbon additions on some physicomechanical properties of zirconium diboride  

Microsoft Academic Search

ZrB2 and ZrC powders of approximately the same fineness (specific surface S = 0.12-0.16 m2\\/g) and a much finer PGI graphite powder (S = 12 m2\\/g) were employed. The compositions of the zirconium carbide and zirconium boride were close to stoichiometric; the oxygen and nitrogen contents of the compounds did not exceed a few tenths of one percent. As in

R. A. Andrievskii; L. A. Korolev; V. V. Klimenko; A. G. Lanin; I. I. Spivak; I. L. Taubin

1980-01-01

72

Low Dose Irradiation Growth in Zirconium.  

National Technical Information Service (NTIS)

Low dose neutron irradiation growth in textured and recrystallized zirconium, is studied, at the Candu Reactors Calandria temperature (340 K) and at 77 K. It was necessary to design and build 1: A facility to irradiate at high temperatures, which was inst...

A. M. Fortis

1987-01-01

73

Mass Spectrometric Study of Zirconium Diboride.  

National Technical Information Service (NTIS)

A mass spectrometer was used with a high temperature Knudsen effusion source to obtain vapor pressure data for zirconium diboride in the temperature range 2267 to 2445K. The heat of vaporization at 298K determined from a Third Law analysis of the data is ...

O. C. Trulson H. W. Goldstein

1964-01-01

74

Grain growth in zirconium diboride during sintering  

Microsoft Academic Search

The results are presented of an investigation into the growth of zirconium diboride grains during sintering. It is assumed that, during the initial period of sintering, grain growth is effected by a mechanism of grain displacement under the influence of surface tension forces, when grain matching occurs on polygonized boundaries. At sintering time of more than 30 min, grain growth

M. A. Kuzenkova; P. S. Kislyi

1966-01-01

75

Aluminum alloys containing scandium with zirconium additions  

US Patent & Trademark Office Database

Applications for aluminum alloys containing scandium with or without zirconium additions. Such modified aluminum alloys possess enhanced properties and exhibit improved processing characteristics, and, as such, are especially suited for use in recreational and athletic structures and components, and in certain aerospace, ground transportation and marine structures and components.

1997-04-15

76

Zirconium modified nickel-copper alloy  

NASA Technical Reports Server (NTRS)

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

Whittenberger, J. D. (inventor)

1977-01-01

77

Zirconium alloy heat treatment process and product  

SciTech Connect

Zirconium-base alloy channels and fuel cladding tubes having unique resistance to accelerated pustular corrosion in the boiling water reactor environment are produced by a heat treatment causing segregation of intermetallic particulate precipitate phase in two dimensional arrays preferably located along grain boundaries and subgrain boundaries throughout the alloy body.

Black, T.J.; Proebstle, R.A.; Urquhart, A.W.; Walker, J.L.; Williams, C.D.

1980-12-09

78

Minerals Yearbook, 1988: Zirconium and Hafnium.  

National Technical Information Service (NTIS)

Domestic mine production of zircon, the principal ore mineral of zirconium and hafnium, increased in 1988. Zircon was mined by two companies in Florida as a coproduct of the titanium minerals ilmenite and rutile and by one company in New Jersey from taili...

J. B. Hedrick

1988-01-01

79

Zirconium and hafnium in meteorites  

NASA Astrophysics Data System (ADS)

The ratio of the two refractory trace elements zirconium (Zr) and hafnium (Hf) in meteorites has been proposed to be uniform. The most precise value available is 34.3+/-0.2 (1?). It was obtained by isotope dilution ICP-MS applied to 15 chondrites, most of which were carbonaceous chondrites, and six achondrites. We reinvestigated the case and determined Zr/Hf ratios of a broad spectrum of meteoritic samples via laser ablation ICP-MS. Our sample suite comprised 29 chondrites and five achondrites. The main objective of the study was two-fold: we intended to verify the accuracy and precision of a relatively fast and inexpensive sample preparation method combined with expeditious laser ablation ICP-MS techniques. Furthermore, we were looking into the possibility of systematic fine-scale Zr/Hf variations among bulk meteoritic matter of different classes. The applied fusion technique together with laser ablation ICP-MS turned out to be well suited to determine relative refractory trace element abundances. Absolute Zr/Hf ratios yield uncertainties of approximately 4% (1?). As opposed to the most recent findings, we observed variable Zr/Hf ratios in different meteorites ranging from approximately 28 to approximately 38. Our value for Orgueil (CI1) is 34.0+/-0.3 (1?). Including literature data, we propose a solar system value of 34.1+/-0.3. Our data also suggest that H chondrites tend to exhibit higher Zr/Hf ratios (average of 35.6+/-0.5 [1?]) while EL6 chondrites rather show low values (average of 30.8+/-0.6 [1?]). In addition to examining Zr/Hf ratios, we also explored the content of refractory major elements in different meteorite groups. Here, we found that EL6 chondrites often show very low Ca/Al ratios. The CI1 value for CaO/Al2O3 is 0.804. EL6 chondrites, however, display ratios as low as approximately 0.3. While the variation in Zr/Hf can be explained by fractional condensation processes in the early solar nebula, the observed low Ca/Al ratios in EL6 chondrites are probably attributable to deficits in oldhamite (CaS).

Patzer, Andrea; Pack, Andreas; Gerdes, Axel

2010-07-01

80

p97 complexes as signal integration hubs  

PubMed Central

In the ubiquitin-proteasome system, a subset of ubiquitylated proteins requires the AAA+ ATPase p97 (also known as VCP or Cdc48) for extraction from membranes or protein complexes before delivery to the proteasome for degradation. Diverse ubiquitin adapters are known to link p97 to its client proteins, but two recent papers on the adapter protein UBXD7, including one by Bandau et al. in BMC Biology, suggest that rather than simply linking p97 to ubiquitylated proteins, this adapter may be essential to coordinate ubiquitylation and p97-mediated extraction of the proteasome substrate. These findings add to growing indications of richly diverse roles of adapters in p97-mediated signaling functions. See research article: http://www.biomedcentral.com/1741-7007/10/36

2012-01-01

81

Investigation of the Oxidation Resistance of Zirconium Boride-Molybdenum Disilicide Alloys.  

National Technical Information Service (NTIS)

This work examines the oxidation resistance of pure zirconium boride and zirconium boride-molybdenum disilicide alloys. It was found that the oxidation resistance of the zirconium boride-molybdenum disilicide alloys considerably exceeds that of pure zirco...

M. A. Kuzenkova P. S. Kislyi

1966-01-01

82

Manufacturing process to reduce large grain growth in zirconium alloys  

DOEpatents

It is an object of the present invention to provide a procedure for desensitizing zirconium-based alloys to large grain growth (LGG) during thermal treatment above the recrystallization temperature of the alloy. It is a further object of the present invention to provide a method for treating zirconium-based alloys which have been cold-worked in the range of 2 to 8% strain to reduce large grain growth. It is another object of the present invention to provide a method for fabricating a zirconium alloy clad nuclear fuel element wherein the zirconium clad is resistant to large grain growth.

Rosecrans, P.M.

1984-08-01

83

Plastic deformation mechanisms of {beta} treated zirconium  

SciTech Connect

This study aims to determine the different deformation mechanisms of grade 702 zirconium under uniaxial tension and at room temperature. The grade 702 zirconium tested had undergone an {alpha} {yields} {beta} {yields} {alpha} cycle at a slow cooling rate ({approximately} 15{degree} s{sup {minus}1}). Three deformation mechanisms were identified: prismatic slip, (10{bar 1}2) <10{bar 1}{bar 1}> twinning and (11{bar 2}1) <11{bar 2}{bar 6}> twinning. The critical resolved shear stress for prismatic slip, (10{bar 1}2) <10{bar 1}{bar 1}> twinning and (11{bar 2}1) <11{bar 2}{bar 6}> twinning was also determined. The effect of the non-uniform redistribution of the hardening elements on location through the grain of the various mechanisms and on the tendency for localized deformation to develop is also discussed.

Crepin, J.; Bretheau, T.; Caldemaison, D. [Ecole Polytechnique, Palaiseau (France). Lab. de Mecanique des Solides] [Ecole Polytechnique, Palaiseau (France). Lab. de Mecanique des Solides

1995-10-01

84

Intercalation chemistry of zirconium 4-sulfophenylphosphonate  

NASA Astrophysics Data System (ADS)

Zirconium 4-sulfophenylphosphonate is a layered material which can be employed as a host for the intercalation reactions with basic molecules. A wide range of organic compounds were chosen to represent intercalation ability of zirconium 4-sulfophenylphosphonate. These were a series of alkylamines from methylamine to dodecylamine, 1,4-phenylenediamine, p-toluidine, 1,8-diaminonaphthalene, 1-aminopyrene, imidazole, pyridine, 4,4?-bipyridine, poly(ethylene imine), and a series of amino acids from glycine to 6-aminocaproic acid. The prepared compounds were characterized by powder X-ray diffraction, thermogravimetry analysis and IR spectroscopy and probable arrangement of the guest molecules in the interlayer space of the host is proposed based on the interlayer distance of the prepared intercalates and amount of the intercalated guest molecules.

Svoboda, Jan; Zima, Vít?zslav; Melánová, Klára; Beneš, Ludvík; Trchová, Miroslava

2013-12-01

85

50 CFR 300.97 - Inseason orders.  

Code of Federal Regulations, 2013 CFR

...INTERNATIONAL FISHERIES REGULATIONS Fraser River Sockeye and Pink Salmon Fisheries § 300.97 Inseason orders. (a) During...procedures section of the annual management measures for West Coast Salmon Fisheries, published in the Federal Register ; Treaty...

2013-10-01

86

46 CFR 111.97-7 - Distribution.  

Code of Federal Regulations, 2013 CFR

...Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Electric Power-Operated Watertight Door Systems § 111.97-7 Distribution. (a) Each...

2013-10-01

87

47 CFR 97.119 - Station identification.  

Code of Federal Regulations, 2013 CFR

...RADIO SERVICES AMATEUR RADIO SERVICE Station Operation Standards § 97.119 Station identification. (a) Each amateur station, except a space station or telecommand station, must transmit its assigned call sign on its...

2013-10-01

88

46 CFR 97.53-1 - Officers.  

Code of Federal Regulations, 2013 CFR

... Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS OPERATIONS Exhibition of Merchant Mariner Credential § 97.53-1 Officers. All officers on a vessel must have their licenses or...

2013-10-01

89

50 CFR 300.97 - Inseason orders.  

Code of Federal Regulations, 2010 CFR

...INTERNATIONAL FISHERIES REGULATIONS Fraser River Sockeye and Pink Salmon Fisheries § 300.97 Inseason orders. (a) During...procedures section of the annual management measures for West Coast Salmon Fisheries, published in the Federal Register ; Treaty...

2010-10-01

90

50 CFR 300.97 - Inseason orders.  

Code of Federal Regulations, 2011 CFR

...INTERNATIONAL FISHERIES REGULATIONS Fraser River Sockeye and Pink Salmon Fisheries § 300.97 Inseason orders. (a) During...procedures section of the annual management measures for West Coast Salmon Fisheries, published in the Federal Register ; Treaty...

2011-10-01

91

50 CFR 300.97 - Inseason orders.  

Code of Federal Regulations, 2012 CFR

...INTERNATIONAL FISHERIES REGULATIONS Fraser River Sockeye and Pink Salmon Fisheries § 300.97 Inseason orders. (a) During...procedures section of the annual management measures for West Coast Salmon Fisheries, published in the Federal Register ; Treaty...

2012-10-01

92

Electronic structure of insulating zirconium nitride  

Microsoft Academic Search

The electronic structure of Zr3N4, grown by low-energy (0.25 keV) N+2 implantation of polycrystalline zirconium has been investigated by x-ray photoelectron spectroscopy. Both the valence-band and core-level spectra demonstrate the insulating characteristics of Zr3N4 as well as the metal-insulator phase transition in ZrNx when x~=1.33.

P. Prieto; L. Galán; J. M. Sanz

1993-01-01

93

Zirconium alloys in nuclear power engineering  

Microsoft Academic Search

Results of studies of zirconium alloys É110 and É635 that have served in parts of VVÉR-1000 reactors are presented. The influence of the composition on the properties of alloys É110 and É635 is studied and improved modifications are suggested. The effect of the total content of admixtures in alloy É110 on corrosion and embrittlement of pipes under conditions simulating LOCA

A. V. Nikulina

2004-01-01

94

Oxide layers with titanium and zirconium phosphates  

Microsoft Academic Search

Oxide-phosphate layers 20 to 150 ?m thick were obtained on titanium by plasma electrolytic deposition in individual and mixed\\u000a aqueous electrolytes with polyphosphate complexes of zirconium(IV), barium(II), and copper(II). Formation features, thickness,\\u000a elemental and phase compositions, and surface morphology of the films are presented. Depending on the electrolyte composition,\\u000a synthesis conditions, and temperature of annealing in air, some simple and

V. S. Rudnev; T. P. Yarovaya; P. M. Nedozorov; T. A. Kaidalova

2008-01-01

95

Thermal sprayed zirconium coatings for corrosion resistance  

SciTech Connect

Vacuum Plasma Spraying (VPS) is conducted in inert reduced pressures. This results in higher particle velocities than in atmospheric plasma spraying. Reverse arc sputter cleaning and pre-heating of the workpiece lead to elevated substrate temperatures during deposition, allowing sintering of the coating and, thus, enhanced densities and bond strengths. Inert Environment Electric Arc Spraying (IEAS) is performed in inert gas chambers, utilizing wire as the feedstock. This leads to lower gas content in the coating, since the initial gas content in wire is lower than that of the powder feedstock used in VPS. Controlled atmosphere sprayed zirconium coatings had inferior mechanical and corrosion properties when compared with bulk zirconium. The VPS coatings displayed higher bond strengths and better cavitation erosion resistance than did the IEAS coatings. The IEAS coatings had lower gas content and showed better electrochemical and corrosion behavior. The lower gas content for IEAS was due to a lower initial gas level in the wire feedstock used in this process. Also, scanning electron microscopy revealed that larger particles result in the IEAS process. Thus, a smaller surface-area-to-volume ratio is available for gas-metal reactions to occur. Improvements in mechanical and corrosion properties for the IEAS coatings were due to elevated substrate temperatures during deposition. Compressive surface stresses induced by post-spray shot-peening enhanced corrosion and cavitation resistance of IEAS coatings. Coating porosity caused failure during immersion testing. Therefore, it was concluded that controlled environment thermal spraying of zirconium is not suitable for forming corrosion resistant coatings on steel. ZrN coatings were formed by electric arc spraying using a nitrogen shroud and post-spray nitriding. Two phases; ZrN and zirconium solid solution, exist in the as-sprayed coating. Nitriding increases the proportion of ZrN.

Bamola, R.K.

1992-01-01

96

Thermodynamics of the gaseous zirconium iodides  

Microsoft Academic Search

The gaseous zirconium iodides ZrIâ, ZrIâ, ZrIâ, and ZrI, generated by the reaction of HI(g) with Zr(s) at elevated temperatures, were identified and characterized thermochemically by Knudsen cell mass spectrometry. Gaseous ZrIâ was the major reaction product up to about 1300°K; above this temperature, atomic I became the major product, with minor amounts of the lower Zr iodides appearing as

P. D. Kleinschmidt; D. Cubicciotti; D. L. hildenbrand

1978-01-01

97

Ion Exchange Reversibility of Some Radionuclides on Zirconium Tungstosuccinate and Zirconium Tungstosalicylate at their Solid-Liquid Interfaces  

Microsoft Academic Search

Zirconium tungstosuccinate (ZWSu) and zirconium tungstosalicylate (ZWSa) composites were synthesized by anchoring moieties of succinic acid (SuA) and salicylic acid (SaA) onto zirconium tungstate (ZW), respectively. The produced exchange composites were unambiguously characterized by TGA, DTA, XRD, and FTIR spectroscopy. Thermally stable, amorphous, highly active, and multifunctional inorganic-organic exchangers were produced. The sorption behavior of the hybrid materials for removal

B. El-Gammal; K. F. Allan

2012-01-01

98

Corrosion resistant zirconium alloy absorber material  

SciTech Connect

A method is described of making a zirconium alloy absorber material comprising the steps of: providing a zirconium alloy having iron in a range from about 0.2 to about 0.5 wt. %; about 50 to 120 ppm silicon; about 1,000 to 2,000 ppm oxygen; one or more additional alloying metals selected from the group consisting of tin in a range of from a measurable amount up to about 1.4 wt. chromium in a range from about 0.07 to about 0.25 wt. niobium in a range from a measurable amount up to about 0.6 wt. %, and vanadium in a range of from a measurable amount up to about 0.5 wt. %; and a balance of zirconium; and adding erbium in a range of from about 0.05 to 2.0 wt. % selected from the group consisting of a naturally occurring distribution of erbium isotopes, isotopically enriched erbium- 167, and a combination thereof to act as a burnable absorber.

Pati, S.R.; Corsetti, L.V.

1993-08-31

99

Neutronographic Texture Analysis of Zirconium Based Alloys  

NASA Astrophysics Data System (ADS)

Neutron diffraction is a very powerful tool in texture analysis of zirconium based alloys used in nuclear technique. Textures of five samples (two rolled sheets and three tubes) were investigated by using basal pole figures, inversion pole figures, and ODF distribution function. The texture measurement was performed at diffractometer KSN2 on the Laboratory of Neutron Diffraction, Department of Solid State Engineering, Faculty of Nuclear Sciences and Physical Engineering, CTU in Prague. Procedures for studying textures with thermal neutrons and procedures for obtaining texture parameters (direct and inverse pole figures, three dimensional orientation distribution function) are also described. Observed data were processed by software packages HEXAL and GSAS. Our results can be summarized as follows: i) All samples of zirconium alloys show the distribution of middle area into two maxima in basal pole figures. This is caused by alloying elements. A characteristic split of the basal pole maxima tilted from the normal direction toward the transverse direction can be observed for all samples, ii) Sheet samples prefer orientation of planes (100) and (110) perpendicular to rolling direction and orientation of planes (002) perpendicular to normal direction, iii) Basal planes of tubes are oriented parallel to tube axis, meanwhile (100) planes are oriented perpendicular to tube axis. Level of resulting texture and maxima position is different for tubes and for sheets. The obtained results are characteristic for zirconium based alloys.

Kruželová, M.; Vratislav, S.; Kalvoda, L.; Dlouhá, M.

2012-02-01

100

The p97-FAF1 Protein Complex Reveals a Common Mode of p97 Adaptor Binding*  

PubMed Central

p97, also known as valosin-containing protein, is a versatile participant in the ubiquitin-proteasome system. p97 interacts with a large network of adaptor proteins to process ubiquitylated substrates in different cellular pathways, including endoplasmic reticulum-associated degradation and transcription factor activation. p97 and its adaptor Fas-associated factor-1 (FAF1) both have roles in the ubiquitin-proteasome system during NF-?B activation, although the mechanisms are unknown. FAF1 itself also has emerging roles in other cell-cycle pathways and displays altered expression levels in various cancer cell lines. We have performed a detailed study the p97-FAF1 interaction. We show that FAF1 binds p97 stably and in a stoichiometry of 3 to 6. Cryo-EM analysis of p97-FAF1 yielded a 17 ? reconstruction of the complex with FAF1 above the p97 ring. Characteristics of p97-FAF1 uncovered in this study reveal common features in the interactions of p97, providing mechanistic insight into how p97 mediates diverse functionalities.

Ewens, Caroline A.; Panico, Silvia; Kloppsteck, Patrik; McKeown, Ciaran; Ebong, Ima-Obong; Robinson, Carol; Zhang, Xiaodong; Freemont, Paul S.

2014-01-01

101

Electronic structure and charge density of zirconium diboride  

Microsoft Academic Search

Self-consistent calculations of the electronic band structure of zirconium diboride, ZrB2, have been performed. The total and individual band charge densities are analyzed in terms of their site (zirconium or boron) symmetry and plotted. The total charge density shows very little charge asymmetry about either site.

Alfred C. Switendick

1991-01-01

102

Effect of Neutron Irradiation on Fracture Behavior of Zirconium  

Microsoft Academic Search

Detailed fractographic and microstructural examinations were made on neutron irradiated and unirradiated zirconium specimens deformed to fracture at temperatures between liquid nitrogen (77 K) and room temperature (295 K), to study the effect of neutron irradiation on the fracture behavior of zirconium. The fracture surface and the micro-structure of the necked portion of the specimen were observed by scanning and

Takeo ONCHI; Hideo KAYANO; Yasuhiro HIGASHIGUCHI

1980-01-01

103

Electronic structure and charge density of zirconium diboride  

Microsoft Academic Search

Self-consistent calculations of the electronic band structure of zirconium diboride, ZrBâ, have been performed. The total and individual band charge densities are analysed in terms of their site (zirconium or boron) symmetry and plotted. The total charge density shows very little charge asymmetry about either site. 6 refs., 6 figs., 37 tabs.

Switendick

1990-01-01

104

Electronic structure and charge density of zirconium diboride  

SciTech Connect

Self-consistent calculations of the electronic band structure of zirconium diboride, ZrB{sub 2}, have been performed. The total and individual band charge densities are analysed in terms of their site (zirconium or boron) symmetry and plotted. The total charge density shows very little charge asymmetry about either site. 6 refs., 6 figs., 37 tabs.

Switendick, A.C.

1990-01-01

105

Electronic structure and charge density of zirconium diboride  

NASA Astrophysics Data System (ADS)

Self-consistent calculations of the electronic band structure of zirconium diboride, ZrB2, have been performed. The total and individual band charge densities are analyzed in terms of their site (zirconium or boron) symmetry and plotted. The total charge density shows very little charge asymmetry about either site.

Switendick, Alfred C.

1991-07-01

106

Electronic structure and charge density of zirconium diboride  

SciTech Connect

Self-consistent calculations of the electronic band structure of zirconium diboride, ZrB{sub 2}, have been performed. The total and individual band charge densities are analyzed in terms of their site (zirconium or boron) symmetry and plotted. The total charge density shows very little charge asymmetry about either site.

Switendick, A.C. (Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States))

1991-07-01

107

Corrosion resistance of zirconium in chemical processing equipment  

SciTech Connect

The author describes some corrosion properties that make unalloyed zirconium a candidate material for the chemical process industry. Zirconium is compared with competitive materials of construction; corrosion problems and testing are described; aspects of fabrication are discussed. The paper concludes with a description of applications in the Du Pont Company.

Moniz, B.J.

1982-09-01

108

Frottement Lubrifie de la Zircone (Lubricated Friction of Zirconium).  

National Technical Information Service (NTIS)

The friction and wear behavior of zirconium in the presence of different lubricating agents was studied, and the wear mechanisms analyzed. A model of the wear evolution is developed. The friction/wear meter was of a sphere-plane type where the zirconium w...

P. Maurin-Perrier

1987-01-01

109

Process of precipitating zirconium or hafnium from spent pickling solutions  

Microsoft Academic Search

This patent describes a process for regenerating a spent, fluoride-containing pickle solution used in the pickling of zirconium or hafnium metal or their alloys. It comprises adding to the spent pickle solution a sufficient amount of sodium sulfate to precipitate sodium zirconium or hafnium fluoride.

C. L. Aguilar; R. G. Walker

1991-01-01

110

Separation of fluorine from zirconium and hafnium hydroxofluorides  

Microsoft Academic Search

Translated from Zh. Prikl. Khim.; 46: No. 7, 1438-1443(Jul For ; separation of fluorine by electrodialysis it is recommended that membranes which ; are inent with respect to zirconium fluoride complexes be used. Intensive ; separation of fluorine from zirconium (or hafnium) hydroxofluoride can be ; achieved by high-voltage electrodialysis at voltages above 600 V. The existence ; of previously

M. M. Godneva; D. L. Motov

1973-01-01

111

Process of precipitating zirconium or hafnium from spent pickling solutions  

SciTech Connect

This patent describes a process for regenerating a spent, fluoride-containing pickle solution used in the pickling of zirconium or hafnium metal or their alloys. It comprises adding to the spent pickle solution a sufficient amount of sodium sulfate to precipitate sodium zirconium or hafnium fluoride.

Aguilar, C.L.; Walker, R.G.

1991-12-31

112

Zirconium fluoride glass - Surface crystals formed by reaction with water  

NASA Technical Reports Server (NTRS)

The hydrated surfaces of a zirconium barium fluoride glass, which has potential for application in optical fibers and other optical elements, were observed by scanning electron microscopy. Crystalline zirconium fluoride was identified by analysis of X-ray diffraction patterns of the surface crystals and found to be the main constituent of the surface material. It was also found that hydrated zirconium fluorides form only in highly acidic fluoride solutions. It is possible that the zirconium fluoride crystals form directly on the glass surface as a result of its depletion of other ions. The solubility of zirconium fluoride is suggested to be probably much lower than that of barium fluoride (0.16 g/100 cu cm at 18 C). Dissolution was determined to be the predominant process in the initial stages of the reaction of the glass with water. Penetration of water into the glass has little effect.

Doremus, R. H.; Bansal, N. P.; Bradner, T.; Murphy, D.

1984-01-01

113

Swift heavy ion irradiation of zirconium phosphate of various forms  

NASA Astrophysics Data System (ADS)

The zirconium phosphate and its various derivatives have good resistance against ionization radiation, as it was found earlier during the irradiation of them with ?-rays of high energy. Continuing these experiments amorphous and crystalline (both ?- and ?-forms) zirconium phosphate, its monosodium, and propylamine intercalated forms were irradiated with a fluence of 10 11-10 14 ion cm -2 with swift heavy ions of 203Bi and 84Kr. The irradiation was also performed with Si containing zirconium phosphate. The structure of the materials was characterized by XRD method. The comparison of the powder diffraction patterns reveals that the irradiation has practically no effect on the ?-zirconium phosphate, while the other materials more or less destroyed and some of them became amorphous. The propylamine intercalate form of zirconium phosphate is decomposed on ?-ZrP and organic radical.

Szirtes, L.; Megyeri, J.; Kuzmann, E.; Havancsák, K.

2003-06-01

114

Irradiation growth in zirconium and its alloys  

NASA Astrophysics Data System (ADS)

The UKAEA Northern Research Laboratories (Risley) have recently completed an underlying research study on irradiation growth in zirconium and its alloys. During this study, irradiation growth measurements have been made on a range of well-characterized single-crystal and polycrystalline iodide zirconium, commercial alloys Zircaloy-2 and Zr-2.5 wt% Nb, and high-purity zirconium-tin alloys in different metallurgical conditions following irradiation in the DIDO reactor at AERE Harwell. Irradiations were performed in three rigs operating at irradiation temperatures between 353 and 673 K. An important feature of the experimental programme was the capability to perform repeat length measurements on individual growth specimens at intervals during their irradiation programme. This facility has allowed accurate monitoring of the growth phenomenon and changes in growth behaviour induced by the combined effects of irradiation temperature and accumulated fast neutron dose over large dose ranges. This paper reviews the main experimental results from this programme and discusses them in terms of current understanding of the growth process. Thus, it has been observed that, in annealed Zircaloy-2 at temperatures between 553 and 673 K, a transition from saturating growth to accelerating growth rates occurs with increasing dose. The dose above which this "growth breakaway" takes place is seen to be inversely dependent on irradiation temperature in mis temperature range. The well-documented difference in growth behaviour between annealed and cold-worked Zircaloy-2 observed at relatively low irradiation temperatures, in which cold-worked material grows at a high linear rate over large dose ranges, is not observed at 673 K. Comparison is made with reported results on similar material irradiated in other irradiation facilities. The growth data are interpreted in terms of recent theories regarding the development during fast neutron irradiation of a cold-worked microstructure consisting of < a>- and < c>-type dislocations. Irradiation growth behaviour of annealed polycrystalline iodide zirconium between 353 and 673 K contrasts strongly with that in annealed Zircaloy-2 with low irradiation growth rates being observed over a large dose and temperature range. The influence of key irradiation parameters on the growth process have been examined in a series of studies initiated as part of a collaborative programme with AECL Chalk River Nuclear Labs. Final results from the studies on annealed and deformed single-crystal zirconium are reported here. They show that growth saturates rapidly at low dose in annealed single-crystal material irradiated at 353 and 553 K but that a gradual increase in growth strain is observed on irradiation to high dose at 553 K. Single-crystal specimens heavily swaged prior to irradiation at 353 K and given different pre-irradiation heat-treatments exhibit high near-linear or accelerating growth rates. These growth data are interpreted in terms of the importance of grain boundaries and twin boundaries as sinks for point defects which allow point defect separation and hence growth to continue to high dose. Finally, the results of growth experiments performed on Zr-0.1% Sn and Zr-1.5% Sn alloys at 353 and 553 K are reviewed. These experiments confirm the important role played by alloying additions and impurities on the growth process in zirconium and Zircaloy-2.

Rogerson, A.

1988-10-01

115

34 CFR 97.109 - IRB review of research.  

Code of Federal Regulations, 2011 CFR

... 2011-07-01 false IRB review of research. 97.109 Section 97.109 Education...Basic ED Policy for Protection of Human Research Subjects) § 97.109 IRB review of research. (a) An IRB shall review and...

2011-07-01

116

34 CFR 97.109 - IRB review of research.  

Code of Federal Regulations, 2010 CFR

... 2010-07-01 false IRB review of research. 97.109 Section 97.109 Education...Basic ED Policy for Protection of Human Research Subjects) § 97.109 IRB review of research. (a) An IRB shall review and...

2010-07-01

117

34 CFR 97.109 - IRB review of research.  

Code of Federal Regulations, 2012 CFR

... 2012-07-01 false IRB review of research. 97.109 Section 97.109 Education...Basic ED Policy for Protection of Human Research Subjects) § 97.109 IRB review of research. (a) An IRB shall review and...

2012-07-01

118

The irradiation effects on zirconium alloys  

NASA Astrophysics Data System (ADS)

Pressure tube samples were irradiated under helium atmosphere in the TRIGA Steady State Research and Material Test Reactor of the Romanian Institute for Nuclear Research (INR). These samples are made of the Zr-2.5%Nb alloy used as structural material for the CANDU Romanian power reactors. After irradiation, mechanical tests were performed in the Post Irradiation Examination Laboratory (PIEL) to study the influence of irradiation on zirconium alloys mechanical behaviour. The tensile test results were used for structural integrity assessment. Results of the tests are presented. The paper presents, also, pressure tube structural integrity assessment.

Negut, Gh.; Ancuta, M.; Radu, V.; Ionescu, S.; Stefan, V.; Uta, O.; Prisecaru, I.; Danila, N.

2007-05-01

119

Electron-momentum distribution in zirconium  

SciTech Connect

The electron-momentum distribution in hexagonal-close-packed zirconium has been studied for the first time with use of a Compton-scattering technique. Measurements have been made by scattering 59.54-keV ..gamma.. rays. Theoretical computations have been carried out with use of the renormalized-free-atom model for various 4d-5s configurations. Best agreement between theory and experiment is found if the electron configuration is chosen as 4d/sup 3/5s/sup 1/.

Sharma, B.K.; Ahuja, B.L.

1988-08-15

120

DlgS97/SAP97, a Neuronal Isoform of Discs Large, Regulates Ethanol Tolerance  

PubMed Central

From a genetic screen for Drosophila melanogaster mutants with altered ethanol tolerance, we identified intolerant (intol), a novel allele of discs large 1 (dlg1). Dlg1 encodes Discs Large 1, a MAGUK (Membrane Associated Guanylate Kinase) family member that is the highly conserved homolog of mammalian PSD-95 and SAP97. The intol mutation disrupted specifically the expression of DlgS97, a SAP97 homolog, and one of two major protein isoforms encoded by dlg1 via alternative splicing. Expression of the major isoform, DlgA, a PSD-95 homolog, appeared unaffected. Ethanol tolerance in the intol mutant could be partially restored by transgenic expression of DlgS97, but not DlgA, in specific neurons of the fly’s brain. Based on co-immunoprecipitation, DlgS97 forms a complex with N-methyl-D-aspartate (NMDA) receptors, a known target of ethanol. Consistent with these observations, flies expressing reduced levels of the essential NMDA receptor subunit dNR1 also showed reduced ethanol tolerance, as did mutants in the gene calcium/calmodulin-dependent protein kinase (caki), encoding the fly homolog of mammalian CASK, a known binding partner of DlgS97. Lastly, mice in which SAP97, the mammalian homolog of DlgS97, was conditionally deleted in adults failed to develop rapid tolerance to ethanol’s sedative/hypnotic effects. We propose that DlgS97/SAP97 plays an important and conserved role in the development of tolerance to ethanol via NMDA receptor-mediated synaptic plasticity.

Kong, Eric C.; Slawson, Justin B.; Griffith, Leslie C.; Takamiya, Kogo; Huganir, Richard L.; Margolis, Ben; Heberlein, Ulrike

2012-01-01

121

Retrospective Reactor Dosimetry with Zirconium Alloy Samples  

SciTech Connect

Retrospective measurements are routinely performed with stainless steel samples. Recent experiments have been successfully conducted using zirconium alloy samples, involving somewhat different neuron activation reactions than are normally encountered with stainless steel samples. The alloy composition consisted of nominally 1% (by weight) niobium, 1% tin, and 0.1% iron, with the balance zirconium. The activation products observed in the samples by gamma spectroscopy included Zr-95, Nb-95, Sn-113, Sb-125, Mn-54, Co-60, Nb-94, and Ta-182. The niobium was then chemically separated following ASTM procedure E1297 and the Nb-93m activities were measured by x-ray spectroscopy. The thermal neutron fluences, as determined independently by the neutron capture gamma reactions to Zr-95, Sn-113, Nb-94, and Sn/Sb-125, were in excellent agreement. The fast neutron fluences, as determined separately by the Fe-54(n,p)Mn-54 and Nb-93(n,n’)Nb-93m reactions, were also in good agreement, thus demonstrating the versatility of the retrospective dosimetry technique.

Greenwood, Lawrence R.; Foster, John P.

2009-11-01

122

Kinetics of formation of a platelet-reinforced ceramic composite prepared by the directed reaction of zirconium with boron carbide  

Microsoft Academic Search

In this paper the kinetics of formation of a new class of ceramic composite material, zirconium diboride platelet-reinforced zirconium carbides, are discussed. These materials are prepared by the directed reaction of molten zirconium with boron carbide to form a ceramic material composed of zirconium diboride platelets approximately uniformly distributed in a zirconium carbide matrix containing a controlled amount of residual

William B. Johnson; Alan S. Nagelberg; Else Breval

1991-01-01

123

Synthetic environment technologies in STOW 97  

NASA Astrophysics Data System (ADS)

The synthetic theater of war (STOW) is the major application of a Defense Advanced Research Projects Agency (DARPA) thrust in advanced distributed simulation (ADS). The STOW Program focuses on an advanced concept technology demonstration (ACTD) termed STOW 97 sponsored by DARPA with the United States Atlantic Command (USACOM). The successful implementation of STOW 97 technologies in November 1997 with the United Endeavor 98-1 exercise will mark the full operational capacity of the USACOM Joint Training, Analysis and Simulation Center. To support ADS applications up to the Joint Task Force level, STOW seeks to develop and demonstrate technologies enabling the integration of war-fighting through virtual and constructive simulations from geographically distributed locations in a common synthetic battlespace.

Turner, Jeffrey T.; Koklauner, Karl

1997-10-01

124

STS-97 ISS Science Payloads Briefing  

NASA Technical Reports Server (NTRS)

John Un, International Space Station (ISS) Lead Increment Scientist, gives an overview of the STS-97 Endeavour mission payload (PV Module P6) and Expedition 1 crew. He describes the research and experimentation to take place on the ISS in the following fields: (1) Life Sciences, (2) Microgravity Research, (3) Commercial, (4) Space Sciences, and (5) Earth Sciences. Observations of Earth include images of the Aral Sea in central Asia and fires in Mongolia. Mr. Un then answers questions from the press.

2000-01-01

125

Atomic layer deposition of zirconium silicate films using zirconium tetrachloride and tetra-n-butyl orthosilicate  

Microsoft Academic Search

Atomic layer chemical vapor deposition of zirconium silicate films with a precursor combination of ZrCl4 and tetra-n-butyl orthosilicate (TBOS) was studied for high dielectric gate insulators. The effect of deposition conditions, such as deposition temperature, pulse time for purge and precursor injection on the deposition rate per cycle, and composition of the film were studied. At 400 °C, the growth

Won-Kyu Kim; Sang-Woo Kang; Shi-Woo Rhee; Nae-In Lee; Jong-Ho Lee; Ho-Kyu Kang

2002-01-01

126

Electronic structure of the cubic phase of zirconium dioxide  

Microsoft Academic Search

The band structure of the cubic phase of zirconium dioxide is obtained by employing the LMTO method. Its PV-diagram is calculated to determine the equilibrium lattice constant. The emission Zr LIII-spectrum of this compound is interpreted.

A. E. Krasovskii; A. S. Katashinskii; N. V. Parldaomenko

1994-01-01

127

Laves intermetallics in stainless steel-zirconium alloys.  

National Technical Information Service (NTIS)

Laves intermetallics have a significant effect on properties of metal waste forms being developed at Argonne National Laboratory. These waste forms are stainless steel-zirconium alloys that will contain radioactive metal isotopes isolated from spent nucle...

D. P. Abraham S. M. McDeavitt J. W. Richardson

1997-01-01

128

40 CFR 721.10152 - Oxirane, substituted silylmethyl-, hydrolysis products with alkanol zirconium(4+) salt and silica...  

Code of Federal Regulations, 2011 CFR

...products with alkanol zirconium(4+) salt and silica, acetates (generic). 721...products with alkanol zirconium(4+) salt and silica, acetates (generic). ...products with alkanol zirconium(4+) salt and silica, acetates (PMN...

2011-07-01

129

Modelling precipitation in zirconium niobium alloys  

NASA Astrophysics Data System (ADS)

A model has been developed to predict precipitation of ?-Nb in zirconium-niobium alloys. The model considers two transformation mechanisms; in situ transformation of any retained ?-Zr and homogeneous nucleation of ?-Nb. The two mechanisms are allowed to operate concurrently and compete for the available solute. The model has been calibrated and tested using data in the literature and is able to reasonably reproduce these results without introducing non-physical fitting parameters. It has then been applied to predict the effects of prior ?-Zr fraction, oxygen content, and temperature on the precipitation kinetics of ?-Nb. These calculations predict that prior ?-Zr fraction has a strong effect on the kinetics of subsequent ?-Nb evolution and that oxygen content is also critical, with higher oxygen levels predicted to result in faster kinetics and shift in the peak transformation rate to higher temperatures.

Robson, J. D.

2008-07-01

130

Zirconium deformation behavior: insights from EBSD measurements.  

SciTech Connect

The deformation of crystal-bar zirconium was investigated as a function of strain and strain rate through electron back-scattered diffraction (EBSD) characterization. The resultant data provided spatially resolved information on microstructure and texture evolution, individual twin system activity, and subsequent strain partitioning between twinned volume and parent grains. A range of deformation conditions was represented through quasi-static compression, 4-point beam bend tests at room and cryogenic temperature, and Taylor cylinder impact experiments. Effects from the interplay between slip and twinning deformation modes on anisotropic plasticity are considered in order to address the apparent trend toward isotropy at high rates. The role of various length scales on deformation behavior will be considered, along with the implications of these length scales on the assumptions typically invoked for plasticity modeling.

Bingert, J. F. (John F.); Mason, T. A. (Thomas A.); Kaschner, G. C. (George C.); Maudlin, P. J. (Paul J.); Gray, G. T. (George T.), III

2001-01-01

131

On the dynamic tensile strength of Zirconium  

NASA Astrophysics Data System (ADS)

Despite its fundamental nature, the process of dynamic tensile failure (spall) is poorly understood. Spall initiation via cracks, voids, etc, before subsequent coalesce, is known to be highly microstructure-dependant. In particular, the availability of slip planes and other methods of plastic deformation controls the onset (or lack thereof) of spall. While studies have been undertaken into the spall response of BCC and FCC materials, less attention has paid to the spall response of highly anisotropic HCP materials. Here the dynamic behaviour of zirconium is investigated via plate-impact experiments, with the aim of building on an ongoing in-house body of work investigating these highly complex materials. In particular, in this paper the effect of impact stress on spall in a commercially sourced Zr rod is considered, with apparent strain-rate softening highlighted.

Appleby-Thomas, G. J.; Hameed, A.; Vignjevic, R.; Hazell, P. J.; Painter, J.; Cademartori, S.

2014-05-01

132

Electronic Structures of Zirconium Hydride and Hydrogen Solid Solution  

Microsoft Academic Search

Electronic structures of zirconium hydride and hydrogen solid solution have been evaluated by the X?ray photoelec- tron spectroscopy andrst-principles molecular orbital calculation. From the valence band spectra of the solid zirconium hydride, the occurrence of the valence electron transfer from Zr 4d band to Zr?H bonding state was found to induce the reduction of Zr?Zr metallic bonds with increasing the

Takanori NISHIZAKI; Shinsuke YAMANAKA

133

Nitridation of zirconium using energetic ions from plasma focus device  

Microsoft Academic Search

The nitridation of zirconium disks is achieved by irradiating energetic nitrogen ions from 2.3 kJ plasma focus device using multiple focus deposition shots (10, 20, 30 and 40) at different angular positions with respect to the anode axis. The X-ray diffraction analysis reveals the evolution of ZrN, Zr2N and Zr3N4 phases of zirconium nitride depending upon the ion energy flux and

I. A. Khan; M. Hassan; R. Ahmad; A. Qayyum; G. Murtaza; M. Zakaullah; R. S. Rawat

2008-01-01

134

Laves intermetallics in stainless steel-zirconium alloys  

Microsoft Academic Search

Laves intermetallics have a significant effect on properties of metal waste forms being developed at Argonne National Laboratory. These waste forms are stainless steel-zirconium alloys that will contain radioactive metal isotopes isolated from spent nuclear fuel by electrometallurgical treatment. The baseline waste form composition for stainless steel-clad fuels is stainless steel-15 wt.% zirconium (SS-15Zr). This article presents results of neutron

D. P. Abraham; S. M. McDeavitt; J. W. Jr. Richardson

1997-01-01

135

The freezing on of zirconium boride thermocouple sheaths  

Microsoft Academic Search

1.The freezing on method of preparation of zirconium boride sheaths is highly promising, and secures blank-shaping properties which are not exceeded by the properties of sheaths made by die extrusion.2.The best processing characteristics are shown by fine zirconium boride powder slips with 8–10% paraffin wax and 1% of oleic acid, from which it is possible to produce blanks with a

P. S. Kislyi; M. A. Kuzenkova

1965-01-01

136

Critical role of nitrogen during high temperature scaling of zirconium  

NASA Technical Reports Server (NTRS)

The mechanisms of scale cracking, scale color changes, and scale growth, and their interrelations, were studied in zirconium specimens at elevated temperatures in air, oxygen and nitrogen. Nitrogen was found to be responsible for monoclinic-to-cubic ZrO2 conversion, for scale cracking and breakaway on zirconium nitride, and for the formation of ZrN on the metal interface underneath an outer oxide layer.

Evans, E. B.; Tsangarakis, N.; Probst, H. B.; Garibotti, N. J.

1973-01-01

137

Quercetin as colorimetric reagent for determination of zirconium  

USGS Publications Warehouse

Methods described in the literature for the determination of zirconium are generally designed for relatively large amounts of this element. A good procedure using colorimetric reagent for the determination of trace amounts is desirable. Quercetin has been found to yield a sensitive color reaction with zirconium suitable for the determination of from 0.1 to 50?? of zirconium dioxide. The procedure developed involves the separation of zirconium from interfering elements by precipitation with p-dimethylaminoazophenylarsonic acid prior to its estimation with quercetin. The quercetin reaction is carried out in 0.5N hydrochloric acid solution. Under the operating conditions it is indicated that quercetin forms a 2 to 1 complex with zirconium; however, a 2 to 1 and a 1 to 1 complex can coexist under special conditions. Approximate values for the equilibrium constants of the complexes are K1 = 0.33 ?? 10-5 and K2 = 1.3 ?? 10-9. Seven Bureau of Standards samples of glass sands and refractories were analyzed with excellent results. The method described should find considerable application in the analysis of minerals and other materials for macro as well as micro amounts of zirconium.

Grimaldi, F. S.; White, C. E.

1953-01-01

138

STS-97 Endeavour after RSS rollback  

NASA Technical Reports Server (NTRS)

After rollback of the Rotating Service Structure (at left), Space Shuttle Endeavour stands ready for launch targeted for 10:06 p.m. EST tonight on mission STS-97 to the International Space Station. The orbiter carries the P6 Integrated Truss Segment containing solar arrays that will be temporarily installed to the Unity connecting module by the Z1 truss, recently delivered to and installed on the Station on mission STS-92. The two solar arrays are each more than 100 feet long. They will capture energy from the sun and convert it to power for the Station. Two spacewalks will be required to install the solar array connections.

2000-01-01

139

Chromatographic separation of sodium, cobalt and europium on the particles of zirconium molybdate and zirconium silicate ion exchangers  

Microsoft Academic Search

Zirconium molybdate and zirconium silicate were prepared by application of the precipitation and sol–gel routes, respectively. The produced ion exchange powders were physically characterized using X-ray diffraction, infrared and differential thermal analysis. The obtained data revealed that they are thermally and chemically stable, having unique microstructure properties that permit their use in chromatographic separation of Na+, Co2+, and Eu3+ from

B. El-Gammal; S. A. Shady

2006-01-01

140

Erythroderma: A clinical study of 97 cases  

PubMed Central

Background Erythroderma is a rare skin disorder that may be caused by a variety of underlying dermatoses, infections, systemic diseases and drugs. Methods We reviewed the clinical, laboratory and biopsy material of 97 patients diagnosed with erythroderma who were treated in our department over a 6-year period (1996 through 2002). Results The male-female ratio was 1.85:1. The mean age at diagnosis was 46.2 years. The most common causative factors were dermatoses (59.7%), followed by drug reactions (21.6%), malignancies (11.3%) and idiopathic causes (7.2%). Carbamazepine was the most common drug (57.1%). The best clinicopathologic correlation was found in cutaneous T-cell lymphoma and pityriasis rubra pilaris related erythroderma. Apart from scaling and erythema that were present in all patients, pruritus was the most common finding (97.5%), followed by fever (33.6%), lymphadenopathy (21.3%), edema (14.4%) and hyperkeratosis (7.2%). Conclusion This study outlines that underlying etiologic factors of erythroderma may show geographic variations. Our series had a high percentage of erythroderma secondary to preexisting dermatoses and a low percentage of idiopathic cases. There was no HIV-infected patient among our series based on multiple serum antibody tests. The clinical features of erythroderma were identical, irrespective of the etiology. The onset of the disease was usually insidious except in drug-induced erythroderma, where it was acute. The group associated with the best prognosis was that related to drugs.

Akhyani, Maryam; Ghodsi, Zahra S; Toosi, Siavash; Dabbaghian, Hossein

2005-01-01

141

Zirconium and Niobium Extraction from HCl Media with di-N-Butyl Phosphorodithioic Acid.  

National Technical Information Service (NTIS)

The solvent extraction of zirconium and niobium di-n-butyl phosphoroditioate into organic diluents from HCl media is presented. The effect of extractant and mineral acid concentration on the zirconium and niobium distribution ratios as plots of lg. distri...

V. C. Iliescu

1978-01-01

142

Chemistry of Zirconium Related to the Behavior of Nuclear Fuel Cladding. Final Report.  

National Technical Information Service (NTIS)

Studies of the chemistry of the zirconium-iodine and zirconium-oxygen systems were undertaken to elucidate their thermodynamics and kinetics. It is anticipated that the results obtained will lead to an improved understanding of the chemical processes invo...

D. Cubicciotti

1980-01-01

143

24 CFR 200.97 - Adjustments resulting from cost certification.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 false Adjustments resulting from cost certification. 200.97 Section 200...Eligibility Requirements for Existing Projects Cost Certification § 200.97 Adjustments resulting from cost certification. (a) Fee simple...

2012-04-01

144

24 CFR 200.97 - Adjustments resulting from cost certification.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Adjustments resulting from cost certification. 200.97 Section 200...Eligibility Requirements for Existing Projects Cost Certification § 200.97 Adjustments resulting from cost certification. (a) Fee simple...

2010-04-01

145

24 CFR 200.97 - Adjustments resulting from cost certification.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 false Adjustments resulting from cost certification. 200.97 Section 200...Eligibility Requirements for Existing Projects Cost Certification § 200.97 Adjustments resulting from cost certification. (a) Fee simple...

2011-04-01

146

24 CFR 200.97 - Adjustments resulting from cost certification.  

...2014-04-01 false Adjustments resulting from cost certification. 200.97 Section 200...Eligibility Requirements for Existing Projects Cost Certification § 200.97 Adjustments resulting from cost certification. (a) Fee simple...

2014-04-01

147

24 CFR 200.97 - Adjustments resulting from cost certification.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 false Adjustments resulting from cost certification. 200.97 Section 200...Eligibility Requirements for Existing Projects Cost Certification § 200.97 Adjustments resulting from cost certification. (a) Fee simple...

2013-04-01

148

Biodistribution of Ru-97-Labeled DTPA, DMSA and Transferrin.  

National Technical Information Service (NTIS)

Ruthenium-97 is being produced at the Brookhaven Linac Isotope Producer (BLIP). The favorable physical properties of Ru-97 and chemical reactivity of ruthenium offer a potential for using this isotope to label compounds useful for delayed scanning. Diethy...

A. B. Brill H. L. Atkins P. Som R. G. Fairchild Z. H. Oster

1980-01-01

149

7 CFR 3201.97 - Sun care products.  

...2014-01-01 2014-01-01 false Sun care products. 3201.97 Section 3201... Designated Items § 3201.97 Sun care products. (a) Definition. ...preference for qualifying biobased sun care products. By that date, Federal...

2014-01-01

150

46 CFR 97.37-23 - Hand portable fire extinguishers.  

Code of Federal Regulations, 2013 CFR

... 2013-10-01 2013-10-01 false Hand portable fire extinguishers. 97.37-23...Emergency Equipment, Etc. § 97.37-23 Hand portable fire extinguishers. (a) Each hand portable fire extinguisher shall be...

2013-10-01

151

46 CFR 97.37-13 - Fire extinguishing system controls.  

Code of Federal Regulations, 2010 CFR

...2009-10-01 false Fire extinguishing system controls. 97.37-13 Section... § 97.37-13 Fire extinguishing system controls. (a) The control cabinets or spaces containing...manifolds for the various fire extinguishing...

2009-10-01

152

46 CFR 97.37-13 - Fire extinguishing system controls.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 false Fire extinguishing system controls. 97.37-13 Section...Etc. § 97.37-13 Fire extinguishing system controls. The control cabinets or spaces containing...manifolds for the various fire extinguishing...

2013-10-01

153

46 CFR 97.37-13 - Fire extinguishing system controls.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Fire extinguishing system controls. 97.37-13 Section... § 97.37-13 Fire extinguishing system controls. (a) The control cabinets or spaces containing...manifolds for the various fire extinguishing...

2010-10-01

154

47 CFR 97.211 - Space telecommand station.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Space telecommand station. 97.211 Section 97...designated by the licensee of a space station is eligible to transmit as a telecommand station for that space station, subject to the...

2013-10-01

155

18 CFR 401.97 - Enforcement of penalties.  

Code of Federal Regulations, 2013 CFR

...2012-04-01 true Enforcement of penalties. 401.97 Section 401.97 Conservation of Power and Water Resources DELAWARE RIVER BASIN COMMISSION ADMINISTRATIVE MANUAL RULES OF PRACTICE AND PROCEDURE Penalties and Settlements in Lieu...

2013-04-01

156

Crystallization Behavior of M97 Series Silicone Cushions.  

National Technical Information Service (NTIS)

M97 series siloxanes are poly(dimethyl-diphenyl) siloxanes that are reinforced through a mixture of precipitated and fumed silica fillers which are blended in through the addition of a short chain polydimethylsiloxane processing aid. M97 silicones exhibit...

A. Chien S. DeTeresa R. Cohenour J. Schnieder J. LeMay B. Balazs

2000-01-01

157

STS-97 Endeavour after RSS rollback  

NASA Technical Reports Server (NTRS)

As dawn breaks on the horizon, Space Shuttle Endeavour is seen standing ready for launch, targeted for 10:06 p.m. EST tonight on mission STS-97 to the International Space Station. The Rotating Service Structure was rolled back just before dawn. On top of the orange external tank is the Gaseous Oxygen Vent Arm and its vent hood, known as the '''beanie cap.''' The hood is raised to clear the external tank 2.5 minutes before launch. The orbiter carries the P6 Integrated Truss Segment containing solar arrays that will be temporarily installed to the Unity connecting module by the Z1 truss, recently delivered to and installed on the Station on mission STS-92. The two solar arrays are each more than 100 feet long. They will capture energy from the sun and convert it to power for the Station. Two spacewalks will be required to install the solar array connections.

2000-01-01

158

STS-97 Endeavour after RSS rollback  

NASA Technical Reports Server (NTRS)

Against a cloudless blue sky, Space Shuttle Endeavour stands ready for launch after the rollback of the Rotating Service Structure, at left. Endeavour is targeted for launch tonight at about 10:06 p.m. EST on mission STS-97 to the International Space Station. The orbiter carries the P6 Integrated Truss Segment containing solar arrays that will be temporarily installed to the Unity connecting module by the Z1 truss, recently delivered to and installed on the Station on mission STS-92. The two solar arrays are each more than 100 feet long. They will capture energy from the sun and convert it to power for the Station. Two spacewalks will be required to install the solar array connections.

2000-01-01

159

Interaction of ytterbium trifluoride with zirconium in a NaF-ZrF 4 molten mixture  

Microsoft Academic Search

The interaction of ytterbium trifluoride with zirconium in a molten mixture of sodium and zirconium fluorides have been studied\\u000a by differential thermal analysis, X-ray diffraction, and electronic and IR spectroscopy. In the temperature range 440–640°C,\\u000a zirconium reduces YbF3 to ytterbium. The reaction products also contain low-valence zirconium and ytterbium compounds.

N. M. Kompanichenko; R. N. Savchuk; N. V. Faidyuk; A. A. Omel’chuk; V. F. Zinchenko; N. I. Buryak

2008-01-01

160

Non-chromate corrosion inhibitor formulas based on zirconium vanadium oxide compositions  

US Patent & Trademark Office Database

A mixture of zirconium hydroxides or zirconium basic carbonate with vanadium oxide (V205) co-reacts in high temperature aqueous slurry to form respectively an amorphous material, believed to be based on a zirconium analog of a zeolite structure, and a solid solution of zirconium oxide with vanadium oxide. The subject compositions, free of hexavalent chromium, are highly effective in providing blister-free corrosion prevention in typical coil and aerospace grade epoxy primer and color coat combinations.

2012-03-20

161

47 CFR 97.401 - Operation during a disaster.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Operation during a disaster. 97.401 Section 97.401 Telecommunication FEDERAL...Providing Emergency Communications § 97.401 Operation during a disaster. A station in, or within 92.6 km (50...

2013-10-01

162

47 CFR Appendix 2 to Part 97 - VEC Regions  

Code of Federal Regulations, 2010 CFR

47 Ç Telecommunication Ç 5 Ç 2010-10-01 Ç 2010-10-01 Ç false Ç VEC Regions Ç 2 Ç Appendix 2 to Part 97 Ç Telecommunication Ç FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) Ç SAFETY AND SPECIAL RADIO SERVICES Ç AMATEUR RADIO SERVICE Ç Pt. 97, App. 2 Ç Appendix 2 to Part 97âVEC Regions Ç...

2010-10-01

163

47 CFR Appendix 2 to Part 97 - VEC Regions  

Code of Federal Regulations, 2010 CFR

47 Ç Telecommunication Ç 5 Ç 2009-10-01 Ç 2009-10-01 Ç false Ç VEC Regions Ç 2 Ç Appendix 2 to Part 97 Ç Telecommunication Ç FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) Ç SAFETY AND SPECIAL RADIO SERVICES Ç AMATEUR RADIO SERVICE Ç Pt. 97, App. 2 Ç Appendix 2 to Part 97âVEC Regions Ç...

2009-10-01

164

34 CFR 97.109 - IRB review of research.  

Code of Federal Regulations, 2013 CFR

... 2013-07-01 false IRB review of research. 97.109 Section 97.109 Education...Basic ED Policy for Protection of Human Research Subjects) § 97.109 IRB review of research. (a) An IRB shall review and...

2013-07-01

165

4 CFR 28.97 - Class actions in EEO cases.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Class actions in EEO cases. 28.97 Section 28.97 Accounts...Special Procedures; Equal Employment Opportunity (EEO) Cases § 28.97 Class actions in EEO cases. (a) Prior to invoking the...

2010-01-01

166

4 CFR 28.97 - Class actions in EEO cases.  

Code of Federal Regulations, 2010 CFR

...2009-01-01 2009-01-01 false Class actions in EEO cases. 28.97 Section 28.97 Accounts...Special Procedures; Equal Employment Opportunity (EEO) Cases § 28.97 Class actions in EEO cases. (a) Prior to invoking the...

2009-01-01

167

47 CFR 97.11 - Stations aboard ships or aircraft.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Stations aboard ships or aircraft. 97.11 Section 97...Provisions § 97.11 Stations aboard ships or aircraft. (a) The installation and operation of an amateur station on a ship or aircraft must be approved by the...

2010-10-01

168

47 CFR 97.11 - Stations aboard ships or aircraft.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 false Stations aboard ships or aircraft. 97.11 Section 97...Provisions § 97.11 Stations aboard ships or aircraft. (a) The installation and operation of an amateur station on a ship or aircraft must be approved by the...

2011-10-01

169

47 CFR 97.11 - Stations aboard ships or aircraft.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 false Stations aboard ships or aircraft. 97.11 Section 97...Provisions § 97.11 Stations aboard ships or aircraft. (a) The installation and operation of an amateur station on a ship or aircraft must be approved by the...

2012-10-01

170

47 CFR 97.11 - Stations aboard ships or aircraft.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 false Stations aboard ships or aircraft. 97.11 Section 97...Provisions § 97.11 Stations aboard ships or aircraft. (a) The installation and operation of an amateur station on a ship or aircraft must be approved by the...

2013-10-01

171

46 CFR 97.37-47 - Portable magazine chests.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Portable magazine chests. 97.37-47 Section 97.37-47...Equipment, Etc. § 97.37-47 Portable magazine chests. (a) Portable magazine chests shall be marked in letters at least...

2013-10-01

172

46 CFR 97.01-1 - General; preemptive effect.  

Code of Federal Regulations, 2013 CFR

... 2013-10-01 false General; preemptive effect. 97.01-1 Section 97...Application § 97.01-1 General; preemptive effect. (a) The provisions of...b) The regulations in this part have preemptive effect over State or local...

2013-10-01

173

46 CFR 97.16-1 - Use of auto pilot.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Use of auto pilot. 97.16-1 Section 97.16-1 Shipping... CARGO AND MISCELLANEOUS VESSELS OPERATIONS Auto Pilot § 97.16-1 Use of auto pilot. Except as provided in 33 CFR...

2010-10-01

174

46 CFR 97.16-1 - Use of auto pilot.  

Code of Federal Regulations, 2010 CFR

...2009-10-01 2009-10-01 false Use of auto pilot. 97.16-1 Section 97.16-1 Shipping... CARGO AND MISCELLANEOUS VESSELS OPERATIONS Auto Pilot § 97.16-1 Use of auto pilot. Except as provided in 33 CFR...

2009-10-01

175

LIQUID-LIQUID EXTRACTION OF HAFNIUM FROM ZIRCONIUM BY TRIBUTYL PHOSPHATE  

Microsoft Academic Search

ABS>The removal of hafnium from zirconium is one of a number of ; operations required to produce high purity zirconium metal for use in nuclear ; reactors. Since the metallurgical operations involved in the production of ; zirconium must use the products of hafnium-removal processes, the choice of a ; process for hafnium removal must be integrated with subsequent metallurgical

G. H. Beyer; H. C. Peterson

1951-01-01

176

METALLURGICAL PROBLEMS IN FABRICATION OF ZIRCONIUM-CLAD FUEL ELEMENTS FOR PRESSURIZED WATER REACTORS  

Microsoft Academic Search

To achieve adequate corrosion resistance in high-temperature water, the ; chemical composition and fabrication of zirconium cladding material must be ; carefully controlled. Present technology permits the satisfactory fabrication of ; a variety of fuel materials which are compatible with zirconium cladding. ; Homogeneity and melting cruci-ble problems still exist with some of the fuel ; alloys. Zirconium-clad fuel elements

1958-01-01

177

Synthesis of mesoporous zirconium titanates using alkycarboxylate surfactants and their transformation to dense ceramics  

Microsoft Academic Search

Mesoporous zirconium titanates with Ti\\/Zr ratios of two have been prepared through the controlled hydrolysis of mixtures of zirconium and titanium alkoxides and long chain carboxylates (lauric, palmitic or stearic acids) in the absence of solvent. X-ray diffraction, transmission electron microscopy, and gas adsorption measurements indicate that the zirconium titanate mesophases consist of a disordered arrangement of uniform pores. The

Vittorio Luca; Willem K. Bertram; Jonathan Widjaja; David R. G. Mitchell; Christopher S. Griffith; Elizabeth Drabarek

2007-01-01

178

Synthesis and characterization of a mesoporous hydrous zirconium oxide used for arsenic removal from drinking water  

Microsoft Academic Search

Powder (20–50?m) mesoporous hydrous zirconium oxide was prepared from a zirconium salt granular precursor. The effect of some process parameters on product morphology, porous structure and adsorption performance has been studied. The use of hydrous zirconium oxide for selective arsenic removal from drinking water is discussed.

Anatoly Bortun; Mila Bortun; James Pardini; Sergei A. Khainakov; José R. García

2010-01-01

179

Electrochemical studies of zirconium and hafnium in alkali chloride and alkali fluoride-chloride molten salts  

Microsoft Academic Search

The electrochemical reduction of zirconium and hafnium in alkali chloride or fluoride-chloride molten salts on platinum electrodes has been investigated by means of linear and cyclic voltammetry. It has been found that fluoride ions greatly influenced the reduction of zirconium and hafnium in fluoride-chloride melts. It has been proposed that the mechanism for reduction of zirconium and hafnium in baths

Chen Guang-Sen; Masazumi Okido; Takeo Oki

1990-01-01

180

A case study of the development of a military specification - zirconium powder for thermal batteries  

NASA Astrophysics Data System (ADS)

Thermal batteries are used as the critical power source in nuclear fuses, missiles, and aircraft. Heat sources in thermal batteries use a fine zirconium powder. This report focuses on the zirconium problem and the development of a military specification for zirconium powder as produced by the magnesium reduction method.

Burgess, Mary T.

1987-10-01

181

Equilibrium properties of hcp titanium and zirconium  

NASA Astrophysics Data System (ADS)

The electronic and structural properties of hexagonal-close-packed titanium and zirconium are determined from self-consistent linearized augmented-plane-wave (LAPW) calculations within the framework of the local-density-functional approximation (LDA). The equilibrium lattice parameters, bulk moduli, Poisson's ratios, and cohesive energies are obtained from the total energies calculated as functions of the a and c lattice parameters. As found in other LDA calculations, the cohesive energies are overestimated compared to experiment, but otherwise generally good agreement with experiment is obtained. The uncertainty in the results due to the particular choice of the LDA exchange-correlation potential is also examined by performing parallel calculations using the Kohn-Sham-Gaspar X? (?=(2/3) exchange-only potential. We find that these calculations yield equilibrium volumes which differ by 6-8 % (with the X? results in better agreement with experiment) with proportional differences in other structural properties, which we take to be an indication of the intrinsic reliability of the LDA.

Lu, Zhi-Wei; Singh, David; Krakauer, Henry

1987-11-01

182

Transport properties of zirconium alloy oxide films  

NASA Astrophysics Data System (ADS)

The conductivity mechanism of oxide films on tubes of various zirconium alloys grown in water and steam was investigated by I- V measurements. Electrodes of Ga, Ag, graphite and Au gave different results. The current decrease at voltage application was due to formation of space charge, which could be extracted again as short-circuit current. The positive branch of the I- V characteristics could be fitted by a second-order polynomial. Neither the Schottky emission mechanism nor the Poole-Frenkel effect could be proved. A high invariable carrier concentration with extremely low, but temperature dependent mobility could be proved using the Mott-Guerney relation. The carriers originate from oxygen vacancies in a substoichiometric black oxide layer near the metal-oxide interface. The conduction mechanism is believed to be a hopping process of electrons between oxygen-vacancy traps. There exists a small ionic conduction part, building up an open-circuit voltage so that the I- V characteristics do not pass through the origin. The Meyer-Neldel rule applies.

Frank, H.

2002-12-01

183

SAP97 directs NMDA receptor spine targeting and synaptic plasticity.  

PubMed

SAP97 is a multidomain scaffold protein implicated in the forward trafficking and synaptic localization of NMDA- and AMPA-type glutamate receptors. Alternative splicing of SAP97 transcripts gives rise to palmitoylated ?SAP97 and L27-domain containing ?SAP97 isoforms that differentially regulate the subsynaptic localization of GluR1 subunits of AMPA receptors. Here, we examined whether SAP97 isoforms regulate the mechanisms underlying long-term potentiation (LTP) and depression (LTD) and find that both ?- and ?-forms of SAP97 impair LTP but enhance LTD via independent isoform-specific mechanisms. Live imaging of ?- and ?SAP97 revealed that the altered synaptic plasticity was not due to activity-dependent changes in SAP97 localization or exchange kinetics. However, by recording from pairs of synaptically coupled hippocampal neurons, we show that ?SAP97 occludes LTP by enhancing the levels of postsynaptic AMPA receptors, while ?SAP97 blocks LTP by reducing the synaptic localization of NMDA receptors. Examination of the surface pools of AMPA and NMDA receptors indicates that ?SAP97 selectively regulates the synaptic pool of AMPA receptors, whereas ?SAP97 regulates the extrasynaptic pools of both AMPA and NMDA receptors. Knockdown of ?SAP97 increases the synaptic localization of both AMPA and NMDA receptors, showing that endogenous ?SAP97 restricts glutamate receptor expression at excitatory synapses. This isoform-dependent differential regulation of synaptic versus extrasynaptic pools of glutamate receptors will determine how many receptors are available for the induction and the expression of synaptic plasticity. Our data support a model wherein SAP97 isoforms can regulate the ability of synapses to undergo plasticity by controlling the surface distribution of AMPA and NMDA receptors. PMID:21768261

Li, Dong; Specht, Christian G; Waites, Clarissa L; Butler-Munro, Charlotte; Leal-Ortiz, Sergio; Foote, Janie W; Genoux, David; Garner, Craig C; Montgomery, Johanna M

2011-09-15

184

Thermochemistry of amorphous and crystalline zirconium and hafnium silicates.  

NASA Astrophysics Data System (ADS)

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.

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

2003-03-01

185

Chemistry of zirconium related to the behavior of nuclear fuel cladding. Final report  

SciTech Connect

Studies of the chemistry of the zirconium-iodine and zirconium-oxygen systems were undertaken to elucidate their thermodynamics and kinetics. It is anticipated that the results obtained will lead to an improved understanding of the chemical processes involved in chemically assisted fuel rod failures. This project not only has classified the thermodynamics of both the gas phase and the solids in the zirconium-iodine system, it has also provided valuable information on the chemisorption of iodine and of oxygen on zirconium surfaces at high temperatures. In addition, the kinetics of reactions on zirconium surfaces were studied. These results have already been helpful in understanding the stress corrosion cracking of Zircaloy.

Cubicciotti, D.

1980-03-26

186

Zirconium diboride nanofiber generation via microwave arc heating.  

PubMed

Ultrahigh temperature zirconium diboride nanofibers were produced by microwave arc heating using micron-sized raw powder. While microwave heating the ZrB(2) powder, the development of local arcing led to rapid heating and solidification of the samples, along with the creation of nanofibers. The morphology of these high aspect ratio nanofibers was characterized using scanning electron microscopy and transmission electron microscopy. Energy dispersive x-ray spectroscopy, electron energy loss spectroscopy and selected area electron diffraction showed the composition to contain zirconium, boron, nitrogen, aluminum and oxygen as well as the crystallographic orientation. ZrB(2) nanofiber applications include aerospace and other harsh environments. PMID:21828708

Baldridge, Tyson; Gupta, Mool C

2008-07-01

187

Zirconium diboride nanofiber generation via microwave arc heating  

NASA Astrophysics Data System (ADS)

Ultrahigh temperature zirconium diboride nanofibers were produced by microwave arc heating using micron-sized raw powder. While microwave heating the ZrB2 powder, the development of local arcing led to rapid heating and solidification of the samples, along with the creation of nanofibers. The morphology of these high aspect ratio nanofibers was characterized using scanning electron microscopy and transmission electron microscopy. Energy dispersive x-ray spectroscopy, electron energy loss spectroscopy and selected area electron diffraction showed the composition to contain zirconium, boron, nitrogen, aluminum and oxygen as well as the crystallographic orientation. ZrB2 nanofiber applications include aerospace and other harsh environments.

Baldridge, Tyson; Gupta, Mool C.

2008-07-01

188

In-situ stabilization of radioactive zirconium swarf  

DOEpatents

The method for treating ignitable cutting swarf in accordance with the present invention involves collecting cutting swarf in a casting mold underwater and injecting a binder mixture comprising vinyl ester styrene into the vessel to fill void volume; and form a mixture comprising swarf and vinyl ester styrene; and curing the mixture. The method is especially useful for stabilizing the ignitable characteristics of radioactive zirconium cutting swarf, and can be used to solidify zirconium swarf, or other ignitable finely divided material, underwater. The process could also be performed out of water with other particulate wastes.

Hess, Clay C. (Idaho Falls, ID)

1999-01-01

189

In-situ stabilization of radioactive zirconium swarf  

DOEpatents

The method for treating ignitable cutting swarf in accordance with the present invention involves collecting cutting swarf in a casting mold underwater and injecting a binder mixture comprising vinyl ester styrene into the vessel to fill void volume; and form a mixture comprising swarf and vinyl ester styrene; and curing the mixture. The method is especially useful for stabilizing the ignitable characteristics of radioactive zirconium cutting swarf, and can be used to solidify zirconium swarf, or other ignitable finely divided material, underwater. The process could also be performed out of water with other particulate wastes. 6 figs.

Hess, C.C.

1999-08-31

190

Heavy Ion Irradiation Effects in Zirconium Nitride  

SciTech Connect

Polycrystalline zirconium nitride (ZrN) samples were irradiated with He{sup +}, Kr{sup ++}, and Xe{sup ++} ions to high (>1.10{sup 16} ions/cm{sup 2}) fluences at {approx}100 K. Following ion irradiation, transmission electron microscopy (TEM) and grazing incidence X-ray diffraction (GIXRD) were used to analyze the microstructure and crystal structure of the post-irradiated material. For ion doses equivalent to approximately 200 displacements per atom (dpa), ZrN was found to resist any amorphization transformation, based on TEM observations. At very high displacement damage doses, GIXRD measurements revealed tetragonal splitting of some of the diffraction maxima (maxima which are associated with cubic ZrN prior to irradiation). In addition to TEM and GIXRD, mechanical property changes were characterized using nano-indentation. Nano-indentation revealed no change in elastic modulus of ZrN with increasing ion dose, while the hardness of the irradiated ZrN was found to increase significantly with ion dose. Finally, He{sup +} ion implanted ZrN samples were annealed to examine He gas retention properties of ZrN as a function of annealing temperature. He gas release was measured using a residual gas analysis (RGA) spectrometer. RGA measurements were performed on He-implanted ZrN samples and on ZrN samples that had also been irradiated with Xe{sup ++} ions, in order to introduce high levels of displacive radiation damage into the matrix. He evolution studies revealed that ZrN samples with high levels of displacement damage due to Xe implantation, show a lower temperature threshold for He release than do pristine ZrN samples. (authors)

Egeland, G.W.; Bond, G.M. [New Mexico Institute of Mining and Technology, Socorro, NM 87801 (United States); Valdez, J.A.; Swadener, J.G.; McClellan, K.J.; Maloy, S.A.; Sickafus, K.E. [Los Alamos National Lab (United States); Oliver, B. [Pacific Northwest National Lab (United States)

2004-07-01

191

Electronic structure and chemical bonding in nonstoichiometric zirconium nitrides  

Microsoft Academic Search

X-ray emission spectra were taken and band calculations using the Green function LMTO method and cluster calculations using the discrete variational Xa method were carried out for the electronic structure and chemical bonding parameters for nonstoichiometric zirconium nitrides containing metallic and metalloid vacancies. The existence of structural defects leads to a redistribution of the occupancies of the major sub-bands of

D. L. Novikov; Yu. M. Yarmoshenko; A. L. Ivanovskii; V. A. Gubanov

1989-01-01

192

Study of the Oxidation Behavior of Zirconium and Its Alloys.  

National Technical Information Service (NTIS)

The oxidation behavior of zirconium, Zircaloy-4 and Zr-2,5% Nb alloy, as well as the influence of temperature, oxidising atmosphere, metal composition, heat treatment, surface treatment and specimen size on the oxidation of these materials in the temperat...

I. Costa

1985-01-01

193

Regularities of sintering of zirconium diboride-molybenum alloys  

Microsoft Academic Search

In the process of sintering of mixtures of zirconium diboride with 5, 10, and 15% Mo, specimen growth resulting from heterodiffusion is observed at the instant of formation of solid solution of Mo in ZrB2 during slow heating to high temperatures or during the initial period of isothermal holding in the case of very rapid heating. At temperatures of up

P. S. Kislyi; M. A. Kuzenkova

1966-01-01

194

Casting Titanium and Zirconium in Zircon Sand Molds.  

National Technical Information Service (NTIS)

A zircon sand molding process was developed by the Bureau of Mines for static casting small titanium or zirconium shapes. Castings with unfinished weights up to 3.5 kg (7.7 lb) were produced in an inductoslag furnace and castings up to 7 kg (15.4 lb) were...

J. L. Hoffman M. L. Transue R. A. Beall R. K. Koch

1977-01-01

195

Stress measurements during thin film zirconium oxide growth  

Microsoft Academic Search

Stress accumulation during thin film zirconium oxide growth was successfully measured using new curvature measurement technique and stress of up to 5.1GPa was observed in an approximately 50nm thick oxide film. Experimental results also show that steam and air oxidation make little difference in the stress profile on the oxide film thickness, especially during the early stage of oxidation. This

Yong-Soo Kim; Yong-Hwan Jeong; Jeong-Nam Jang

2011-01-01

196

Method for applying corrosion resistant metallic coating of zirconium nitride  

SciTech Connect

A process is described for enhancing the wear and corrosion resistance of a cladding tube for a nuclear fuel rod, comprising reactively depositing zirconium nitride on the surface of said cladding tube by a cathodic arc plasma deposition process to form a thin wear resistant coating.

Bryan, W.J.; Corsetti, L.V.

1993-07-13

197

Studies on the Characteristic of Zirconium-Tritium Reaction  

NASA Astrophysics Data System (ADS)

The p- c-T curves of tritium absorption and desorption of zirconium were measured using the method of step equilibrium by stepping up the tritium quantity on an experimental apparatus of metal hydride. The p- c-T curves for tritium have one plateau at temperature range from 450 to 500°C and two plateaus at temperature above 600°C. The thermodynamic parameters of the different phases were determined according to the van't Hoff equation. The hysteresis effect was observed in reversible process of tritium absorption and desorption of zirconium on our experimental condition. The tritium absorption behavior by zirconium in the temperature range from 450 to 620°C and desorption behavior of zirconium in the temperature range from 775 to 875°C have been investigated. A method of the reaction rate analysis was proposed and examined for determining the rate constant. The apparent activation energy obtained by this analysis for the absorption and the desorption were (-16.8 ± 0.8) kJ·mol-1 and (57.7 ± 1.6) kJ·mol-1, respectively.

Huang, Gang; Long, Xing-Gui; Peng, Shu-Ming; Liang, Jian-Hua; Yang, Ben-Fu

2011-02-01

198

Study of Zirconium Dioxide White Pigment for Space Environment.  

National Technical Information Service (NTIS)

The properties of zirconium dioxide as a stable white pigment (low alpha/epsilon) for space application are investigated. First, the optical absorption of single crystals is studied, leading to the conclusion that a high degree of purity, except for hafni...

H. K. A. Kan R. J. Champetier T. G. Erler

1970-01-01

199

Sarcoid granulomatosis after zirconium exposure with multiple organ involvement  

Microsoft Academic Search

To the Editor: A 51 yr old, nonsmoking female suffered from relaps- ing progressive pneumonia for several years. The patient had worked for 16 yrs in the nuclear industry and was exposed to grinding particles and welding fumes working with zirkaloy, an alloy containing tin, iron, chromium and zirconium. During an exacerbation of the pneumonia radi- ography of the lung

U. Werfel; J. Schneider; K. Rödelsperger; J. Kotter; W. Popp; H. J. Woitowitz; G. Zieger

1998-01-01

200

Electrochemical Deoxidation of Solid Zirconium Dioxide in Molten Calcium Chloride  

NASA Astrophysics Data System (ADS)

The reduction of zirconium dioxide pellets by electro-deoxidation in molten calcium chloride-calcium oxide (900 °C) has been studied. In this technique, the solid oxide is cathodically polarized against a graphite counter electrode under a constant applied potential. Unlike other metal oxides that have been reduced by this technique, only a small area around the cathodic current-collector wire was reduced to zirconium metal with zirconia pellets sintered at ~1100 °C; the rest of the sample was largely calcium zirconate. Pellets sintered above 1200 °C showed better reduction near the cathode wire and the reduction extended to the entire surface of the pellet with the passage of time. However, reduction of the inner core was found to be increasingly difficult, because the surface metal layer thickened on continuous electro-deoxidation. An analysis of the experimental results showed that the poor electrical conductivity of the intermediate compound, CaZrO3 and its blocky morphology inhibited the electro-deoxidation process. The increase in the sintering temperature of the pellet made it better conducting. However, the pores formed in the thick zirconium metal layer in such samples were too small for an ideal contact between the inner core and the molten electrolyte and hence the reduction of the inner core remained incomplete. Within the scope of this study, it is concluded that preforms with good grain growth and porosity are necessary for the electro-deoxidation of solid zirconium oxide.

Mohandas, K. S.; Fray, D. J.

2009-10-01

201

Zirconium Molybdate Gel as a Generator for Technetium-99M.  

National Technical Information Service (NTIS)

A new sup(99m)Tc generator based on zirconium molybdate gel is described. Essentially the gel is a cation ion exchanger which permits the elution of the pertechnetate ion. The high molybdenum content of this gel, its stability under self-irradiation, and ...

J. V. Evans M. E. Shying

1984-01-01

202

Oxidized zirconium: a potentially longer lasting hip implant  

Microsoft Academic Search

Because younger, more active patients are receiving total hip replacements, it is necessary to develop materials, which would increase the life span of the implants and challenge their wear potential under adverse conditions. Oxidized zirconium (OxZr) is a metal with the surface transformed to ceramic by oxidation that offers low fracture risk and excellent abrasion resistance. This study compared wear

V. Good; K. Widding; G. Hunter; D. Heuer

2005-01-01

203

Extraction of Zirconium from Zircon (A New Process).  

National Technical Information Service (NTIS)

A new process has been used for the extraction of zirconium from zircon. Caustic fritting was done in the presence of magnesium hydroxide carbonate and magnesium oxide. These additives decrease the amount of nitric acid soluble silica less than 1000 ppm. ...

K. A. Shahid D. Saeed S. Jan A. Masood J. Akhtar

1985-01-01

204

Kinetics of chemical interactions between zirconium alloys and stainless steels.  

National Technical Information Service (NTIS)

The chemical interaction kinetics of reactor core component zirconium alloys and stainless steels at high temperatures was examined. Interaction of as-received and preoxidized Zr1%Nb with X18H10T stainless steel used in WWER type nuclear reactors, and als...

J. Frecska L. Maroti L. Matus

1995-01-01

205

Manufacturing process to reduce large grain growth in zirconium alloys  

DOEpatents

A method of treating cold-worked zirconium alloys to reduce large grain gth during thermal treatment at temperatures above the recrystallization temperature of the alloy comprising heating the cold-worked alloy between about 1300.degree.-1350.degree. F. for 1 to 3 hours prior to treatment above its recrystallization temperature.

Rosecrans, Peter M. (Niskayuna, NY) [Niskayuna, NY

1987-01-01

206

Microfiltration Membranes with the Selective Layer Based on Zirconium Dioxide  

Microsoft Academic Search

The effect of zirconium dioxide – polymer (binder) composite on the quality of the microfiltration selective layer is studied. The conditions for deposition of the membrane layer and its drying and firing are established. The characteristics of the porous structure of the obtained membranes are considered.

G. G. Kagramanov; V. V. Nazarov; E. S. Lukin; E. M. Pershikova

2001-01-01

207

97. ORIGINAL ARCHITECT'S MODEL OF BUILDING AS FIRST DESIGNED, NORTH ...  

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

97. ORIGINAL ARCHITECT'S MODEL OF BUILDING AS FIRST DESIGNED, NORTH FRONT - Smithsonian Institution Building, 1000 Jefferson Drive, between Ninth & Twelfth Streets, Southwest, Washington, District of Columbia, DC

208

Thermodynamic and kinetic studies of As(V) removal from water by zirconium oxide-coated marine sand.  

PubMed

Arsenic contamination of groundwater is a major threat to human beings globally. Among various methods available for arsenic removal, adsorption is fast, inexpensive, selective, accurate, reproducible and eco-friendly in nature. The present paper describes removal of arsenate from water on zirconium oxide-coated sand (novel adsorbent). In the present work, zirconium oxide-coated sand was prepared and characterised by infrared and X-ray diffraction techniques. Batch experiments were performed to optimise different adsorption parameters such as initial arsenate concentration (100-1,000 ?g/L), dose (1-8 g/L), pH of the solution (2-14), contact time (15-150 min.), and temperature (20, 30, 35 and 40 °C). The experimental data were analysed by Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models. Furthermore, thermodynamic and kinetic parameters were evaluated to know the mode of adsorption between ZrOCMS and As(V). The maximum removal of arsenic, 97 %, was achieved at initial arsenic concentration of 200 ?g/L, after 75 min at dosage of 5.0 g/L, pH 7.0 and 27 ± 2 °C. For 600 ?g/L concentration, the maximum Langmuir monolayer adsorption capacity was found to be 270 ?g/g at 35 °C. Kinetic modelling data indicated that adsorption process followed pseudo-second-order kinetics. The mechanism is controlled by liquid film diffusion model. Thermodynamic parameter, ?H°, was -57.782, while the values of ?G° were -9.460, -12.183, -13.343 and -13.905 kJ/mol at 20, 30, 35 and 40 °C, respectively, suggesting exothermic and spontaneous nature of the process. The change in entropy, ?S°=?-0.23 kJ/mol indicated that the entropy decreased due to adsorption of arsenate ion onto the solid adsorbent. The results indicated that the reported zirconium oxide-coated marine sand (ZrOCMS) was good adsorbent with 97 % removal capacity at 200 ?g/L concentration. It is interesting to note that the permissible limit of arsenic as per World Health Organization is 10 ?g/L, and in real situation, this low concentration can be achieved through this adsorbent. Besides, the adsorption capacity showed that this adsorbent may be used for the removal of arsenic from any natural water resource. PMID:23423866

Khan, Tabrez Alam; Chaudhry, Saif Ali; Ali, Imran

2013-08-01

209

Electrochemical stripping determination of traces of copper, lead, cadmium and zinc in zirconium metal and zirconium dioxide.  

PubMed

Procedures have been developed for the determination of copper, lead, cadmium and zinc in zirconium metal and zirconium dioxide, at concentrations of 1 ppm or less. Zirconium metal was dissolved in suphuric acid, and zirconium dioxide decomposed under pressure with hydrofluoric acid. Sample solutions were prepared in dilute sulphuric acid. For the stripping determination, the sample solution was either mixed with a complexing tartrate base electrolyte or the pre-electrolysis was carried out in acid solution, with the acid solution being exchanged for a pure base electrolyte (e.g. an acetate buffer) for the stripping step. The stripping step was monitored by d.c., differential pulse and Kalousek commutator voltammetry and the three methods were compared. A stationary mercury-drop electrode can generally be used for all the methods, whereas a mercury-film electrode is suitable only for the d.c. voltammetric determination of copper, lead and cadmium, as pulse measurements with films are poorly reproducible and the electrodes are easily damaged. The relative standard deviation does not exceed 20%. Some samples contained relatively large amounts of copper, which is best separated by electrodeposition on a platinum electrode. PMID:18962277

Stulík, K; Beran, P; Dolezal, J; Opekar, F

1978-07-01

210

Solution-based synthesis and processing of nanocrystalline zirconium diborides-based composites  

NASA Astrophysics Data System (ADS)

Zirconium- and tantalum-based diborides, and diboride/carbide composites are of interest for ultra-high temperature applications requiring improved thermomechanical and thermochemical stability. This thesis focuses on the synthesis, processing and sintering of nanocrystalline powders with Zr- and Ta-based diboride/carbide/silicide compositions. A solution-based processing method was developed to prepare reactive mixtures that were precursors for ZrB2-based powders. The precursors reacted to form the ceramic powders after suitable pyrolysis and borothermal/carbothermal reduction heat treatments. Single-phase ZrB2 powders were prepared with initial composition of C/Zr = 4.8 and B/Zr = 3.0. ZrB2-based composite powders with ZrC, ZrO2, TaB2, TaC, SiC, TaSi 2 and B4C were prepared with particle sizes of 10-500 nm for different phases based SEM micrographs. The composite powders were highly sinterable with proper processing methods developed to avoid and remove oxide impurities. The relative densities of ZrB2/B4C, ZrB 2/TaB2, ZrB2/TaB2/B4C, ZrB 2/TaSi2 were in the range of 91%-97% after pressureless sintering at 2020°C for 1 h or 30 min.

Xie, Yanli

211

45 CFR 97.12 - Which grants may be consolidated?  

Code of Federal Regulations, 2013 CFR

...Health Services, 42 U.S.C. 300x-300x-9. 2 2 See footnote 1 in § 97.12(a)(1). (3) Maternal and Child Health Services, 42 U.S.C. 701-709. 3 3 See footnote 1 in § 97.12(a)(1). (4) Social Services,...

2013-10-01

212

Role of p97/VCP (Cdc48) in genome stability  

PubMed Central

Ubiquitin-dependent molecular chaperone p97, also known as valosin-containing protein (VCP) or Cdc48, is an AAA ATPase involved in protein turnover and degradation. p97 converts its own ATPase hydrolysis into remodeling activity on a myriad of ubiquitinated substrates from different cellular locations and pathways. In this way, p97 mediates extraction of targeted protein from cellular compartments or protein complexes. p97-dependent protein extraction from various cellular environments maintains cellular protein homeostasis. In recent years, p97-dependent protein extraction from chromatin has emerged as an essential evolutionarily conserved process for maintaining genome stability. Inactivation of p97 segregase activity leads to accumulation of ubiquitinated substrates on chromatin, consequently leading to protein-induced chromatin stress (PICHROS). PICHROS directly and negatively affects multiple DNA metabolic processes, including replication, damage responses, mitosis, and transcription, leading to genotoxic stress and genome instability. By summarizing and critically evaluating recent data on p97 function in various chromatin-associated protein degradation processes, we propose establishing p97 as a genome caretaker.

Vaz, Bruno; Halder, Swagata; Ramadan, Kristijan

2013-01-01

213

Syntheses and structural characterization of zirconium-tin and zirconium-lead binary and ternary systems  

SciTech Connect

The binary zirconium-tin system was reinvestigated. The A15 phase appears to be a line phase with a Zr{sub 4}Sn composition. The Zr{sub 5}Sn{sub 3} (Mn{sub 5}Si{sub 3}-type) and Zr{sub 5}Sn{sub 4} (Ti{sub 5}Ga{sub 4}-type) compounds are line phases below 1000{degree}C, the latter being a self-interstitial phase of the former. ZrSn{sub 2} is the tin-richest phase. There is an one-phase region between these phases with partial self-interstitials at high temperatures. The zirconium-lead system behaves similarly: there are an A15 phase with a Zr{sub {approximately}5.8}Pb composition, Zr{sub 5}Pb{sub 3} (Mn{sub 5}Si{sub 3}-type) and Zr{sub 5}Pb{sub 4} (Ti{sub 5}Ga{sub 4-type}) compounds, and a high temperature solid solution between Zr{sub 5}Pb{sub >3.5} and Zr{sub 5}Pb{sub 4} from below 1000{degree}C; however, the ZrSn{sub 2} analogue is not formed. The Mn{sub 5}Si{sub 3}-type phases in these systems can accommodate third elements interstitially to form stoichiometric compounds Zr{sub 5}Sn{sub 3}Z (Z = B, C, N, O, Al, Si, P, S, Cu, Zn, Ga, Ge, and As and Se) and Zr{sub 5}Pb{sub 3}Z (Z = Al, Si, P, S, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Ag, Cd, In, Sn, Sb and Te) as well as their self-interstitial derivatives. The systems Zr-Sn-T, T = Fe, Co and Ni, did not produce stoichiometric interstitial phases Zr{sub 5}Sn{sub 3}T. Instead, the interstitial phases for these elements are formed only with excess tin that partially occupies the interstitial site together with a T element. Reducing the amount of tin in these systems yields two new phases; Zr{sub 5}Sn{sub 2+x}Fe{sub 1-x} (0 {le} {times} {le} 0.28) (W{sub 5}Si{sub 3}-type) and Zr{sub 6}Sn{sub 2}Fe (Zr{sub 6}Al{sub 2}Co-type) as characterized by X-ray single crystal analyses. A cobalt analogue for the latter was also synthesized.

Kwon, Y.U.

1991-01-28

214

Method of purifying zirconium tetrachloride and hafnium tetrachloride in a vapor stream  

SciTech Connect

This patent describes a method of purifying zirconium tetrachloride and hafnium tetrachloride in a vapor stream from a sand chlorinator in which the silicon and metals present in sand fed to the chlorinator are converted to chlorides at temperatures over about 800{degrees} C. It comprises cooling a vapor stream from a sand chlorinator, the vapor stream containing principally silicon tetrachloride, zirconium tetrachloride, and hafnium tetrachloride contaminated with ferric chloride, to a temperature of from about 335{degrees} C to about 600{degrees} C; flowing the vapor stream through a gaseous diffusion separative barrier to produce a silicon tetrachloride-containing vapor stream concentrated in zirconium tetrachloride and hafnium tetrachloride and a silicon tetrachloride-containing vapor stream depleted in zirconium tetrachloride and hafnium tetrachloride; adsorbing the ferric chloride in the separative barrier; and recovering the silicon tetrachloride stream concentrated in zirconium tetrachloride and hafnium tetrachloride separately from the silicon tetrachloride stream depleted in zirconium tetrachloride and hafnium tetrachloride.

Snyder, T.S.; Stolz, R.A.

1992-04-07

215

Preparation and properties of zirconium oxynitrides by the reaction of zirconia with layer structured zirconium nitrochloride  

SciTech Connect

Zirconium oxynitrides were prepared by the reaction of ZrO[sub 2]with layer structured [beta]-ZrNCl at temperatures in a range of 900-1,000C in an ammonia stream. In the reaction, [beta]-ZrNCl acted as a nitrogen source having a composition equivalent to ZrN[sub 4/3], although without the presence of the oxide it was converted into ZrN. Unlike the oxynitride formation from a conventional mixture of ZrN and ZrO[sub 2], the reaction was remarkably fast and completed within 30 min. Two kinds of oxynitride phases, [gamma] and [beta], were obtained, which have fluorite-related superstructures with a range of composition ZrN[sub 4x/3]O[sub 2[minus]2x] (0.5 [le] x [le] 0.8) and an ideal formula Zr[sub 7]N[sub 4]O[sub 8], respectively. Both of the phases are semiconductors with optical band gap energies of 2.50 to 3.20 eV.

Ohashi, Masao; Yamamoto, Hiroyuki; Yamanaka, Shoji; Hattori, Makoto (Hiroshima Univ., Higashi-Hiroshima (Japan))

1993-06-01

216

Penetrate-leach dissolution of zirconium-clad uranium and uranium dioxide fuels  

Microsoft Academic Search

A new decladding-dissolution process was developed for zirconium-clad uranium metal and UO fuels. The proposed penetrate-leach process consists of penetrating the zirconium cladding with Alniflex solution (2M HF--1M HNO--1M Al(NO)--0.1M KCrO) and of leaching the exposed core with 10M HNO. Undissolved cladding pieces are discarded as solid waste. Periodic HF and HNO additions, efficient agitation, and in-line zirconium analyses are

1975-01-01

217

Mechanical characterization of zirconium hydrides with high energy X-ray diffraction  

Microsoft Academic Search

Zirconium and its alloys are of technical importance, finding application as a structural material in the nuclear industry. Engineering components fabricated from zirconium slowly pick-up hydrogen as a result of in-reactor corrosion, degrading the components mechanical properties as a brittle hydride phase forms. This dissertation applies high energy X-ray diffraction to directly measure the mechanical properties of zirconium hydrides in

Matthew Kerr

2009-01-01

218

DELAYED FAILURE HYDROGEN EMBRITTLEMENT OF ZIRCONIUM. Summary Report, September 15, 1961 to September 14, 1962  

Microsoft Academic Search

The extent to which zirconium and zirconium alloys exhibit delayed ; failure (static fatigue) as caused by a combination of absorbed hydrogen and ; applied stress was investigated. Susceptibility to time-dependent fracture was ; evaluated for unalloyed zirconium and Zircaloy-2 with 200 and 500 ppm hydrogen as ; well as for an experimental Zr Al-Sn-Mo alloy and the Canadian Zr-2.5Nb

D. Weinstein; F. C. Holtz

1962-01-01

219

High cycle fatigue properties and microstructure of zirconium and zircaloy-4 under reversal bending  

Microsoft Academic Search

Fatigue lifetime curves of a commercial-purity zirconium and zircaloy-4 were measured under reversal bending. Scanning electron microscopic examination on surfaces of fatigued specimens shows that zirconium displays planar slip, whereas zircaloy-4 displays wavy slip. Fracture surface analysis shows that many fatigue striations with a considerable number of micro-cracks are the primary characters in zirconium and zircaloy-4. Fatigue crack generally nucleates

Xiao Lin; Gu Haicheng

1998-01-01

220

Contamination of silicon dioxide films by aqueous zirconium and hafnium species  

Microsoft Academic Search

Zirconium and hafnium oxides and silicates have emerged as potential replacements for SiO2 as gate dielectric material. Patterning of these materials by wet etching in fabrication areas originally designed for SiO2 gates may give rise to contamination of SiO2 by aqueous zirconium and hafnium species. This paper summarizes the work carried out to characterize the adsorption behavior of aqueous zirconium

V. Lowalekar; S. Raghavan; V. Pandit; H. G. Parks; J. Jeon

2006-01-01

221

Structural and functional characterization of synapse-associated protein-97  

NASA Astrophysics Data System (ADS)

Synapse-associated protein-97 (SAP97) as a scaffold protein plays an important role in regulating neural signal transmission in the central nervous system by coupling with activated membrane receptors, ion channels, and downstream signaling proteins. SAP97 consists of six functional domains: L27, PDZ1, PDZ2, PDZ3, SH3, and GK. Each of these domains mediates the interactions of SAP97 with other proteins. Understanding the molecular mechanism of these interactions in neural signal transmission is a goal of this study. Here high-resolution nuclear magnetic resonance spectroscopy and fluorescence anisotropy are employed towards the goal of the structural and functional characterization of SAP97; specifically, we (a) characterize the binding of the PDZ domains of SAP97 with the C-terminus of NR2B, and determine the structure of the PDZ1-NR2B; (b) characterize the binding of the PDZ domains with the C-terminus of stargazin and multiple mutants, and identify the perturbed amino acids in PDZ2 upon the binding of stargazin; (c) characterize the binding specificity carried by the beta2/beta3 loop of the PDZ3 domain. These results provide insight into the molecular mechanism for the binding specificities of the PDZ domains of SAP97, thereby furthering the development of drugs that target these domains to treat neurological diseases.

Wang, Lei

222

Colloidal and chemical aspects of nanosized hydrated zirconium dioxide synthesized via a sol-gel process.  

PubMed

The processes of coagulation and gelation of sols in zirconium oxychloride aqueous solutions and the properties of hydrated zirconium dioxide sols (pH, particles size, dynamic viscosity) depending on the aging conditions of partially neutralized zirconium oxychloride feedstock solution-zirconyl hydroxychloride used for the synthesis and molar ratio of initial reagents (Zr/NaOH, Zr/CH(3)COO(-)) were first studied in the paper. The concentration and temperature limits of hydrated zirconium dioxide sols stability were determined. The coagulation constant, gelation activation energy, and gelation thermal effect values were found. PMID:21310423

Chepurna, Iryna; Smotraev, Roman; Kanibolotsky, Valentyn; Strelko, Volodymyr

2011-04-15

223

Stress corrosion cracking of zirconium used in the reprocessing plant  

SciTech Connect

We investigated stress corrosion cracking (SCC) of zirconium by constant load test and the small-scale mock-up test simulated the fuel dissolve. These tests operated in the simulated solution, which substituted non-radioactive elements, i.e. V with radioactive elements such as Pu and Np. From the results of constant load test, the cracks were not observed on 150 MPa after 908 hours in approximately 3 % strain. However a lot of cracks caused by SCC were observed over 20 % strain under high tensile stress in the simulated solution and the heat-transfer condition having more corrosive circumstance and noble potential accelerated the susceptibility of SCC. The cracking behavior would be caused by the creep phenomena. The small-scale mock-up test had been operated for about 50000 hours during 7 year. From the results, zirconium showed excellent corrosion resistance and no SCC was observed during these long-term operations. (authors)

Kato, Chiaki; Motooka, Takafumi; Yamamoto, Masahiro [Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195 (Japan)

2007-07-01

224

Corrosion testing of stainless steel-zirconium metal waste form.  

SciTech Connect

Stainless steel-zirconium (SS-Zr) alloys are being considered as waste forms for the disposition of metallic waste generated during the electrometallurgical treatment of spent nuclear fuel. The waste forms contain irradiated cladding hulls, components of the alloy fuel, noble metal fission products, and actinide elements. The baseline waste form is a stainless steel-15 wt% zirconium (SS-15Zr) alloy. This article presents microstructure and some of the corrosion studies being conducted on the waste form alloys. Electrochemical corrosion, immersion corrosion, and vapor hydration tests have been performed on various alloy compositions to evaluate corrosion behavior and resistance to selective leaching of simulated fission products. The SS-Zr waste forms are successful at the immobilization and retention of fission products and show potential for acceptance as high-level nuclear waste forms.

Abraham, D. P.

1998-12-14

225

Corrosion behavior of stainless steel-zirconium alloy waste forms.  

SciTech Connect

Stainless steel-zirconium (SS-Zr) alloys are being considered as waste forms for the disposal of metallic waste generated during the electrometallurgical treatment of spent nuclear fuel. The baseline waste form for spent fuels from the EBR-II reactor is a stainless steel-15 wt.% zirconium (SS-15Zr) alloy. This article briefly reviews the microstructure of various SS-Zr waste form alloys and presents results of immersion corrosion and electrochemical corrosion tests performed on these alloys. The electrochemical tests show that the corrosion behavior of SS-Zr alloys is comparable to those of other alloys being considered for the Yucca Mountain geologic repository. The immersion tests demonstrate that the SS-Zr alloys are resistant to selective leaching of fission product elements and, hence, suitable as candidates for high-level nuclear waste forms.

Abraham, D. P.

1999-01-13

226

Alumina zirconium ceramics synthesis by selective laser sintering/melting  

NASA Astrophysics Data System (ADS)

In the present paper, porous refractory ceramics synthesized by selective laser sintering/melting from a mixture of zirconium dioxide, aluminum and/or alumina powders are subjected to optical metallography and X-ray analysis to study their microstructure and phase composition depending on the laser processing parameters. It is shown that high-speed laser sintering in air yields ceramics with dense structure and a uniform distribution of the stabilizing phases. The obtained ceramic-matrix composites may be used as thermal and electrical insulators and wear resistant coating in solid oxide fuel cells, crucibles, heating elements, medical tools. The possibility to reinforce refractory ceramics by laser synthesis is shown on the example of tetragonal dioxide of zirconium with hardened micro-inclusion of Al 2O 3. By applying finely dispersed Y 2O 3 powder inclusions, the type of the ceramic structure is significantly changed.

Shishkovsky, I.; Yadroitsev, I.; Bertrand, Ph.; Smurov, I.

2007-12-01

227

Charge-optimized many-body (COMB) potential for zirconium  

NASA Astrophysics Data System (ADS)

An interatomic potential for zirconium is developed within the charge-optimized many-body (COMB) formalism. The potential correctly predicts the hexagonal close-packed (HCP) structure as the ground state with cohesive energy, lattice parameters, and elastic constants matching experiment well. The most stable interstitial position is the basal octahedral followed by basal split, in agreement with recent first principles calculations. Stacking fault energies within the prism and basal planes satisfactorily match first principles calculations. A tensile test using nanocrystalline zirconium exhibits both prismatic {1 0 1¯ 0}<1 1 2¯ 0> slip and pyramidal {1 1 2¯ 2}<1 1 2¯ 3¯> slip, showing the model is capable of reproducing the mechanical deformation modes observed in experiments.

Noordhoek, Mark J.; Liang, Tao; Lu, Zizhe; Shan, Tzu-Ray; Sinnott, Susan B.; Phillpot, Simon R.

2013-10-01

228

Infrared and Raman Spectral Studies of Zirconium Hydrated Nitrate  

Microsoft Academic Search

FTIR and Raman spectra of hydratred zirconium nitrate (ZrO(NO3)2.xH2O powdered sample are recorded. The vibrational bands are assigned as fundamental vibrations of NO3- anion and that of water. The observed splitting of v1 (1047 and 1030 cm-1)mode in the Raman spectrum is due to the presence of two distinct types of nitrate groups with an average N-O distance of 1.257

Jobi Jose; M. Junaid Bushiri; K. Jayakumar; V. K. Vaidyan

2008-01-01

229

Infrared and Raman Spectral Studies of Zirconium Hydrated Nitrate  

Microsoft Academic Search

FTIR and Raman spectra of hydratred zirconium nitrate (ZrO(NO3)2?xH2O powdered sample are recorded. The vibrational bands are assigned as fundamental vibrations of NO3? anion and that of water. The observed splitting of v1 (1047 and 1030 cm?1)mode in the Raman spectrum is due to the presence of two distinct types of nitrate groups with an average N&sngbnd;O distance of 1.257

Jobi Jose; M. Junaid Bushiri; K. Jayakumar; V. K. Vaidyan

2008-01-01

230

Immobilization of radioactive wastes: Leachability of glasses containing zirconium  

NASA Astrophysics Data System (ADS)

Sixteen borosilicate glasses containing up to 20% zirconium oxide and 10% simulated fission products or lanthanum oxide were prepared by fusion at 1150 to 1350°C. Their leaching rates in distilled water at 100°C as measured in a Soxhlet extractor varied from 0.9 to 10.9 × 10 -6 g/m 2· s . The results were analysed by multiple linear regression analysis. Some of the glasses studied may constitute a suitable matrix for the disposal of radioactive waste.

St-Pierre, J.; Tran, H. H.; Zikovsky, L.

1982-06-01

231

Fracture behavior of ?-zirconium phosphate-based epoxy nanocomposites  

Microsoft Academic Search

The fracture behaviors of ?-zirconium phosphate (?-ZrP) based epoxy nanocomposites, with and without core-shell rubber (CSR) toughening, were investigated. The state of exfoliation and dispersion of ?-ZrP nanofiller in epoxy were characterized using X-ray scattering and various microscopy tools. The level of enhancement in storage moduli of epoxy nanocomposite against neat epoxy is found to depend on the state of

H.-J. Sue; K. T. Gam; N. Bestaoui; A. Clearfield; M. Miyamoto; N. Miyatake

2004-01-01

232

Trivalent zirconium and hafnium ions in yttrium oxide ceramics  

NASA Astrophysics Data System (ADS)

An analysis of the electron spin resonance (ESR) spectrum of transparent ceramics composed of yttrium oxide with zirconium and hafnium additives has revealed the presence of signals (with similar parameters) from Zr3+ and Hf3+ ions, which have a similar electron configurations of the ground states: [Kr]4 d 1 and [Xe]5 d 1, respectively. It is shown that the pulsed cathodoluminescence spectra of these ions consist of two bands peaking at ? ? 818 and 900 nm.

Solomonov, V. I.; Spirina, A. V.; Konev, S. F.; Cholakh, S. O.

2014-05-01

233

Infiltration of zirconium diboride by ICVI in porous materials  

Microsoft Academic Search

This paper presents the results of an infiltration study, by ICVI, of zirconium diboride into three-dimensional porous preforms to make C\\/ZrB2 composites. An experimental design based on a model substrate shows the level and the sense of the influence of the parameters on the quality and kinetics of infiltration. Dilution of the reactants (BCl3, ZrCl4, H2) by helium improves infiltration

S. Berthon

1997-01-01

234

Pressureless Sintering of Zirconium Diboride: Particle Size and Additive Effects  

Microsoft Academic Search

Zirconium diboride (ZrB2) was densified by pressureless sinte- ring using o4-wt% boron carbide and\\/or carbon as sintering aids. As-received ZrB2 with an average particle size of B2 lm could be sintered to B100% density at 19001C using a combi- nation of boron carbide and carbon to react with and remove the surface oxide impurities. Even though particle size reduction in-

William G. Fahrenholtz; Gregory E. Hilmas; Shi C. Zhang; Sumin Zhu

2008-01-01

235

Pressureless sintering of carbon-coated zirconium diboride powders  

Microsoft Academic Search

Carbon-coated zirconium diboride powders were sintered to near theoretical density at temperatures as low as 1900°C without an external pressure. Relative density increased from ?70% for uncoated ZrB2 to >99% for ZrB2 coated with at least 1.0wt% carbon. Thermodynamic analysis indicated that carbon reacted with and removed oxide impurities (ZrO2 and B2O3) that were present on the particle surfaces, which

Sumin Zhu; William G. Fahrenholtz; Gregory E. Hilmas; Shi C. Zhang

2007-01-01

236

Zirconium diboride nanofiber generation via microwave arc heating  

Microsoft Academic Search

Ultrahigh temperature zirconium diboride nanofibers were produced by microwave arc heating using micron-sized raw powder. While microwave heating the ZrB2 powder, the development of local arcing led to rapid heating and solidification of the samples, along with the creation of nanofibers. The morphology of these high aspect ratio nanofibers was characterized using scanning electron microscopy and transmission electron microscopy. Energy

Tyson Baldridge; Mool C Gupta

2008-01-01

237

The abundances of zirconium and hafnium in the solar system  

Microsoft Academic Search

The concentrations of zirconium and hafnium have been determined in the Orgueil, Murchison, Allende, Bruderheim, and Alais meteorites by radiochemical neutron activation analysis. The mean Zr\\/Hf weight ratio in the first four of these meteorites is 31.3 (plus or minus 2.2), indicating no major fractionation of Zr from Hf. Alais contains anomalously high amounts of many refractory lithophile elements, including

R. Ganapathy; G. M. Papia; LAWRENCE GROSSMAN

1976-01-01

238

Powder metallurgical fabrication of zirconium matrix cermet nuclear fuels  

Microsoft Academic Search

Two powder metallurgical fabrication methods for a zirconium-based cermet nuclear dispersion fuel with oxide microspheres\\u000a have been demonstrated. A multi-pass, cold-drawing process is shown to have excellent capability to control the final matrix\\u000a density, though it requires several high-temperature anneals during fabrication to relieve strain hardening and increase matrix–particle\\u000a bonding. Severe oxide particle damage was observed in the cold-drawn fuel

Aaron R. Totemeier; Sean M. McDeavitt

2009-01-01

239

Oxidation characteristics of molybdenum-zirconium oxide cermets  

NASA Technical Reports Server (NTRS)

The oxidation of molybdenum is affected by the factors of temperature, the oxygen pressure in the oxidizing atmosphere, and the time of exposure. Studies of the oxidation characteristics of Mo show that the oxidation rate increases strongly when the temperature exceeds 600 C. Investigations of the behavior of cermets with various percentages of zirconium oxide are discussed, taking into account oxidation conditions at temperatures under and above the melting point of molybdenum trioxide.

Heitzinger, B.

1984-01-01

240

Microstructure and mechanical properties of proton irradiated zirconium carbide  

Microsoft Academic Search

Zirconium carbide is a candidate ceramic being considered for metal-carbide-base composite-type fuels, as well as for an alternative coating material for TRISO particle fuels. Ensuring adequate mechanical properties and dimensional stability in response to radiation is a key part in developing a practical ZrC-base fuel. The existing available radiation response data for ZrC is limited and insufficient. In the present

Yong Yang; Clayton A. Dickerson; Hannah Swoboda; Brandon Miller; Todd R. Allen

2008-01-01

241

Adsorption of formaldehyde by polyamine-intercalated ?-zirconium phosphate  

NASA Astrophysics Data System (ADS)

Gaseous formaldehyde adsorption mechanism of diethylenetriamine- and pentaethylenehexamine-intercalated ?-zirconium phosphate was demonstrated to be self oxidation-reduction of formaldehyde, that is, Cannizzaro reaction, in the interlayer space as evidenced by XRD and solid-state NMR. This fact suggests that these intercalation compounds can be used as a reaction field of self oxidation-reduction of formaldehyde, and also as adsorbents of formaldehyde, which causes sick-house syndrome.

Nakayama, H.; Hayashi, A.; Eguchi, T.; Nakamura, N.; Tsuhako, M.

2002-08-01

242

Thermal and related studies of some basic zirconium salts  

Microsoft Academic Search

Studies of basic zirconium carbonate, oxalate, nitrate and sulphate using TG, DTA and DTG methods, combined with isothermal gaseous product analyses, IR spectroscopy and X-ray diffraction techniques, have shown that the ease of ligand removal from such salts follows the sequence: ‘loosely bound’ H2O>CO32?? C2O42?>NO3?>OH? (or ‘ tightly bound’ H2O)>SO42?.

F. G. R. Gimblett; A. Hussain; K. S. W. Sing

1988-01-01

243

Oxygen in alloys of titanium with aluminum and zirconium  

Microsoft Academic Search

crease of the ultimate strength by 7-10 kg\\/mm 2, lowers the ductility. However, we found that binary alloys of titanium with aluminum retain fairly good ductility with 3-3.5% A1 when the oxygen content is 0.3-0.35%. In this case the alloy remains ductile, thermally stable, and is weldable and corrosion resistant. This work concerns the effect of zirconium in alloys of

I. I. Kornilov; T. A. Peradze; V. V. Vavilova; L. P. Fatkullina; O. S. Korobov

1973-01-01

244

Isothermal diffusion in uranium-plutonium-zirconium alloys  

NASA Astrophysics Data System (ADS)

Isothermal diffusion couple experiments were performed at 1023 K to investigate diffusion phenomena in body-centered cubic U?Pu?Zr alloys. The U?Pu?Zr alloys covered the uranium-rich corner of the ternary phase diagram with plutonium concentrations up to 27 at.% and zirconium concentrations up to 20 at.%. Ternary interdiffusion coefficients were calculated at the common composition between two couples with intersecting diffusion paths. The cross interdiffusion coefficient for zirconium ( D˜ZrPuU) is negative and has a magnitude twice that of the main coefficient ( D˜ZrZrU). In contrast, D˜PuZrU is negligible compared with D˜PuPuU, D˜PuPuU is an order of magnitude greater than D˜ZrZrU. Average effective interdiffusion coefficients were determined for all components over concentration ranges on the two sides of the Matano plane as well as for the entire diffusion zone of the couples. In general, these coefficients increase with increasing plutonium concentration and decrease with increasing zirconium concentration.

Petri, M. C.; Dayananda, M. A.

1997-01-01

245

40 CFR 763.97 - Compliance and enforcement.  

Code of Federal Regulations, 2013 CFR

...AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT ASBESTOS Asbestos-Containing Materials in Schools § 763.97 ...complaint to the Governor of the State or the EPA Asbestos Ombudsman, 1200 Pennsylvania Ave., NW.,...

2013-07-01

246

97. VIEW OF PIER EXTENSION WITH RAMP IN FOREGROUND AND ...  

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

97. VIEW OF PIER EXTENSION WITH RAMP IN FOREGROUND AND 4TH TEE IN BACKGROUND, LOOKING SOUTHWEST FROM 3RD TEE - Huntington Beach Municipal Pier, Pacific Coast Highway at Main Street, Huntington Beach, Orange County, CA

247

MISSION CONTROL CENTER STATUS REPORT #1 STS-97  

NSDL National Science Digital Library

On Sunday November 30, STS-97 Mission Specialists Carlos Noriega and Joe Tanner began the eleventh space walk in the history of the International Space Station. A daily status report on this mission is available from NASA's Johnson Space Center.

2000-01-01

248

97. BUILDING NO. 539, SMALL ARMS POWDER BLENDER AND PACKING ...  

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

97. BUILDING NO. 539, SMALL ARMS POWDER BLENDER AND PACKING HOUSE, LOOKING NORTH AT SOUTHEAST ELEVATION. - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

249

97. VIEW OF MILL SOLUTION PUMP No. 2 FROM SOUTHEAST. ...  

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

97. VIEW OF MILL SOLUTION PUMP No. 2 FROM SOUTHEAST. SUMPS ARE UNDER FLOOR, BEYOND. STAIR LEADS TO AGITATOR/GOLD TANK ACCESS PLATFORM. - Bald Mountain Gold Mill, Nevada Gulch at head of False Bottom Creek, Lead, Lawrence County, SD

250

Enhanced surveillance program FY97 accomplishments. Progress report  

SciTech Connect

This annual report is one volume of the Enhanced Surveillance Program (ESP) FY97 Accomplishments. The complete accomplishments report consists of 11 volumes. Volume 1 includes an ESP overview and a summary of selected unclassified FY97 program highlights. Volume 1 specifically targets a general audience, reflecting about half of the tasks conducted in FY97 and emphasizing key program accomplishments and contributions. The remaining volumes of the accomplishments report are classified, organized by program focus area, and present in technical detail the progress achieved in each of the 104 FY97 program tasks. Focus areas are as follows: pits; high explosives; organics; dynamics; diagnostics; systems; secondaries; nonnuclear materials; nonnuclear components; and Surveillance Test Program upgrades.

Mauzy, A. [ed.; Laake, B. [comp.

1997-10-01

251

Growth of thin zirconium and zirconium oxides films on the n-GaN(0 0 0 1) surface studied by XPS and LEED  

NASA Astrophysics Data System (ADS)

This work presents the result of the growth of thin zirconium films on the GaN(0 0 0 1) surface under various conditions. In experiment were used the X-ray photoelectron spectroscopy (XPS) and low-energy electron diffraction (LEED) techniques, which allowed to investigate the chemical composition, bonding environment and surface reconstruction. It is shown that zirconium forms ZrN, ZrNxOy, ZrOx and ZrO2 compounds, depending on the selected experimental conditions: the pressure and annealing temperature. Such a varied zirconium growth behaviour is explained by the diffusion of oxygen and nitrogen in the created interface region.

Idczak, K.; Mazur, P.; Zuber, S.; Markowski, L.; Ski?cim, M.; Bili?ska, S.

2014-06-01

252

DLGS97/SAP97 is developmentally upregulated and is required for complex adult behaviors and synapse morphology and function.  

PubMed

The synaptic membrane-associated guanylate kinase (MAGUK) scaffolding protein family is thought to play key roles in synapse assembly and synaptic plasticity. Evidence supporting these roles in vivo is scarce, as a consequence of gene redundancy in mammals. The genome of Drosophila contains only one MAGUK gene, discs large (dlg), from which two major proteins originate: DLGA [PSD95 (postsynaptic density 95)-like] and DLGS97 [SAP97 (synapse-associated protein)-like]. These differ only by the inclusion in DLGS97 of an L27 domain, important for the formation of supramolecular assemblies. Known dlg mutations affect both forms and are lethal at larval stages attributable to tumoral overgrowth of epithelia. We generated independent null mutations for each, dlgA and dlgS97. These allowed unveiling of a shift in expression during the development of the nervous system: predominant expression of DLGA in the embryo, balanced expression of both during larval stages, and almost exclusive DLGS97 expression in the adult brain. Loss of embryonic DLGS97 does not alter the development of the nervous system. At larval stages, DLGA and DLGS97 fulfill both unique and partially redundant functions in the neuromuscular junction. Contrary to dlg and dlgA mutants, dlgS97 mutants are viable to adulthood, but they exhibit marked alterations in complex behaviors such as phototaxis, circadian activity, and courtship, whereas simpler behaviors like locomotion and odor and light perception are spared. We propose that the increased repertoire of associations of a synaptic scaffold protein given by an additional domain of protein-protein interaction underlies its ability to integrate molecular networks required for complex functions in adult synapses. PMID:18171947

Mendoza-Topaz, Carolina; Urra, Francisco; Barría, Romina; Albornoz, Valeria; Ugalde, Diego; Thomas, Ulrich; Gundelfinger, Eckart D; Delgado, Ricardo; Kukuljan, Manuel; Sanxaridis, Parthena D; Tsunoda, Susan; Ceriani, M Fernanda; Budnik, Vivian; Sierralta, Jimena

2008-01-01

253

Fabrication and formation of bioactive anodic zirconium oxide nanotubes containing presynthesized hydroxyapatite via alternative immersion method  

Microsoft Academic Search

Hydroxyapatite (HA) coating has been widely applied on metallic biomedical implants to enhance their biocompatibility. It has been reported that HA coating can be formed on annealed zirconium with anodic zirconium oxide nanotubular arrays after immersion in simulated biological fluid (SBF) for about 14days. In the present study, we apply an alternative immersion method (AIM) to form presynthesized HA on

Lu-Ning Wang; Jing-Li Luo

2011-01-01

254

Wetting and infiltration of zirconium diboride by copper and copper\\/boron alloys  

Microsoft Academic Search

Purpose – This paper investigates wetting and infiltration of zirconium diboride by copper and copper\\/boron alloys in order to more effectively create electrodes for electrical discharge machining. Design\\/methodology\\/approach – A high temperature furnace outfitted with a video recording system was utilized to observe wetting angles between molten copper alloys and zirconium diboride at various temperatures. A parallel, investigation of the

Brent E. Stucker; Walter L. Bradley

2006-01-01

255

Lithium aluminate/zirconium material useful in the production of tritium  

DOEpatents

A composition is described useful in the production of tritium in a nuclear eactor. Lithium aluminate particles are dispersed in a matrix of zirconium. Tritium produced by the reactor of neutrons with the lithium are absorbed by the zirconium, thereby decreasing gas pressure within capsules carrying the material.

Cawley, William E. (Richland, WA); Trapp, Turner J. (Richland, WA)

1984-10-09

256

Lithium aluminate/zirconium material useful in the production of tritium  

DOEpatents

A composition is described useful in the production of tritium in a nuclear reactor. Lithium aluminate particles are dispersed in a matrix of zirconium. Tritium produced by the reactor of neutrons with the lithium are absorbed by the zirconium, thereby decreasing gas pressure within capsules carrying the material.

Cawley, W.E.; Trapp, T.J.

1984-10-09

257

DETERMINATION OF ZIRCONIUM AND HAFNIUM WITH XYLENOL ORANGE AND METHYLTHYMOL BLUE  

Microsoft Academic Search

Both Xylenol Orange and Methylthymol Blue are highly selective and ; sensitive reagents for zirconium and hafnium forming intensely red complexes in ; an acidic medium. The factors affecting the color formation were studied. The ; properties of the complex were determined and compared. In general, zirconium ; forms a more stable complex with the two dyes than hafnium, and

K. L. Cheng

1963-01-01

258

Zirconium Distribution in the System HNO sub 3 -H sub 2 O-TBP-Diluent.  

National Technical Information Service (NTIS)

The extraction behaviour of zirconium in TBP/diluent-HNO sub 3 -H sub 2 O systems is studied in order to increase the uranium decontamination factor by adjusting the extraction conditions so that zirconium extraction is kept at a minimum. Equilibrium diag...

J. Shu, B. F. Araujo

1984-01-01

259

Measurement of impurity diffusion into the liner of a zirconium-lined zircaloy-2 tube  

NASA Astrophysics Data System (ADS)

A method using Auger Electron Spectroscopy (AES) techniques has been developed for measuring the distribution of oxygen and tin across the zirconium liner of zirconium-lined/Zircaloy-2 tubing. This is the first time that an oxygen profile has been successfully measured across the zirconium liner in pilgered tubing. The method is accurate for the determination of oxygen in the concentration range of 100 to 1200 ppm. Measurements were performed on an as-beta-quenched zirconium-lined intermediate size tube sample. The data show negligible tin penetration into the zirconium liner. Oxygen penetration to a depth of 15 to 45 ?m into the zirconium liner was measured at the zirconium liner/Zircaloy-2 interface. Oxygen penetration to a depth of about 20 ?m into the zirconium liner occurred at the inside diameter surface. A methodology for calculating the oxygen diffusion concentration profile was established. The diffusion penetration width geometrically decreases due to tube wall reduction and increases by thermal annealing. When the tubing is processed from the beta-quenched to the final size the diffusion width decreases. Hence, the effect of decreasing wall thickness on the diffusion width is greater than that due to thermal annealing. The calculation methodology could be used to predict the tin and oxygen concentration profiles at the bondline of tubing fabricated by alternate processing sequences.

Foster, John P.; Byers, W. A.

1990-05-01

260

Zirconium-base alloy structural component for nuclear reactor and method  

US Patent & Trademark Office Database

A small amount of lanthanum and praseodymium will substantially improve the slow strain rate ductility of certain zirconium-base alloys and these new alloys and certain other zirconium-base alloys in the irradiated condition can under certain circumstances have surprising load-carrying capacity and service life. Such other alloys contain yttrium or calcium instead of lanthanum or praseodymium.

1980-04-08

261

Vapor transport of zirconium and silicon during heat-treatment of Zircaloy in silica  

Microsoft Academic Search

When pieces of Zircaloy are heated above 600°C in sealed silica capsules, silicon is deposited on the Zircaloy surface as zirconium silicides and zirconium is deposited on the silica in two forms: as an oxide layer in the high temperature region and as a metallic mirror on lower temperature surfaces. Samples of Zircaloy were heated in silica capsules under various

D. R. Knittel; D. Cubicciotti

1980-01-01

262

Preparation of microspherical ?-zirconium phosphate catalysts for conversion of fatty acid methyl esters to monoethanolamides  

Microsoft Academic Search

The performance of solid catalysts and catalyst supports is generally believed to be dependent on their morphology, surface area, and architecture. In order to fully exploit their attractive properties in actual practical applications, layered zirconium phosphate materials should be fabricated into macroscopic form. Here, we report the fabrication of microscopic spheres of ?-zirconium phosphate (?-ZrP) by a spray-drying process. The

Fazhi Zhang; Yaru Xie; Wei Lu; Xiaoying Wang; Sailong Xu; Xiaodong Lei

2010-01-01

263

Resistance a la corrosion du zirconium: mecanismes generaux, comportement en milieu nitrique. (Corrosion resistance of zirconium: general mechanisms, behaviour in nitric acid).  

National Technical Information Service (NTIS)

Corrosion resistance of zirconium results from the strong affinity of this metal for oxygen; as a result a thin protective oxide film is spontaneously formed in air or aqueous media, its thickness and properties depending on the physicochemical conditions...

G. Pinard Legry

1990-01-01

264

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

NASA Technical Reports Server (NTRS)

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.

Dupraw, W. A.

1972-01-01

265

Direct determination of zirconium in alloys by normal and derivative spectrophotometry  

SciTech Connect

This paper discusses the possibility of determining zirconium at a pH 2.8-3.2 with a sensitivity equal to that obtainable in HC1 when using electron spectra and a sensitivity equal to that obtainable in the reaction of zirconium with Arsenazo III in 9-10 M HC1 when using higher-order derivative spectra. This is achieved by adding sodium molybdate ions to the analyzed solution, which also allowed for the determination of zirconium in oxidizing media. The study establishes the formation of a multimetal complex from zirconium ions, arsenazo III, and sodium molybdate. Based on this complex, a method has been developed for the direct determination of zirconium in alloys which distinguishes itself from the known methods by a significantly simpler analytical procedure.

Spitsyn, P.K.

1985-11-01

266

The complexities of p97 function in health and disease  

PubMed Central

p97 is a homohexameric, toroidal machine that harnesses the energy of ATP binding and hydrolysis to effect structural reorganization of a diverse and primarily uncharacterized set of substrate proteins. This action has been linked to endoplasmic reticulum associated degradation (ERAD), homotypic membrane fusion, transcription factor control, cell cycle progression, DNA repair, and post-mitotic spindle disassembly. Exactly how these diverse processes use p97 is not fully understood, but it is clear that binding sites, primarily on the N- and C-domains of p97, facilitate this diversity by coordinating a growing collection of cofactors. These cofactors act at the levels of mechanism, sub-cellular localization, and substrate modification. Another unifying theme is the use of ubiquitylation. Both p97 and many of the associated cofactors have demonstrable ubiquitin-binding competence. The present review will discuss some of the current mechanistic studies and controversies and how these relate to cofactors as well as discussing potential therapeutic targeting of p97.

Chapman, Eli; Fry, Anastasia N.; Kang, MinJin

2011-01-01

267

Influence of zirconium doping on the activities of zirconium and iodine co-doped titanium dioxide in the decolorization of methyl orange under visible light irradiation  

Microsoft Academic Search

Zirconium and iodine co-doped titanium dioxide (Zr–I–TiO2) was prepared by the hydrolysis of tetrabutyl titanate, premixed with zirconium nitrate in an iodic acid aqueous solution, followed by calcination in air. The structure and properties of the resultant catalyst powders were characterized by X-ray diffraction, the Brunauer–Emmett–Teller method, X-ray photoelectron spectroscopy, transmission electron microscopy, and UV–vis absorption spectroscopy. The catalytic activity

Shuang Song; Fangyue Hong; Zhiqiao He; Hongyu Wang; Xianghong Xu; Jianmeng Chen

2011-01-01

268

Tank 241-AP-107, grab samples 7AP-97-1, 7AP-97-2 and 7AP-97-3 analytical results for the final report  

SciTech Connect

This document is the final report for tank 241-AP-107 grab samples. Three grab samples were collected from riser 1 on September 11, 1997. Analyses were performed on samples 7AP-97-1, 7AP-97-2 and 7AP-97-3 in accordance with the Compatibility Grab Sampling and Analysis Plan (TSAP) (Sasaki, 1997) and the Data Quality Objectives for Tank Farms Waste Compatibility Program (DQO) (Rev. 1: Fowler, 1995; Rev. 2: Mulkey and Nuier, 1997). The analytical results are presented in the data summary report (Table 1). A notification was made to East Tank Farms Operations concerning low hydroxide in the tank and a hydroxide (caustic) demand analysis was requested. The request for sample analysis (RSA) (Attachment 2) received for AP-107 indicated that the samples were polychlorinated biphenyl (PCB) suspects. Therefore, prior to performing the requested analyses, aliquots were made to perform PCB analysis in accordance with the 222-S Laboratory administrative procedure, LAP-101-100. The results of this analysis indicated that no PCBs were present at 50 ppm and analysis proceeded as non-PCB samples. The results and raw data for the PCB analysis will be included in a revision to this document. The sample breakdown diagrams (Attachment 1) are provided as a cross-reference for relating the tank farm customer identification numbers with the 222-S Laboratory sample numbers and the portion of sample analyzed.

Steen, F.H.

1997-12-22

269

Tank 241-S-302 grab samples 302S-97-1, 302S-97-2 and 302S-97-3 analytical results for the final report  

SciTech Connect

This document is the final report for tank 241-S-302 grab samples. Three grab samples were collected on January 30, 1998. Analyses were performed on samples 302-S-97-1, 302-S-97-2 and 302-S-97-3 in accordance with the Compatibility Grab Sampling and Analysis Plan (TSAP) (Sasaki, 1997) and the Data Quality Objectives (DQO) for Tank Farms Waste Compatibility Program (Mulkey, 1997). The analytical results are presented in Table 1. No notification limits were exceeded. The sample breakdown diagrams (Attachment 1) are provided as a cross-reference for relating the tank farm customer identification numbers with the 222-S Laboratory sample numbers and the portion of sample analyzed. Table 2 provides the appearance information. Visual observation indicated that the sample was a clear, light-yellow liquid with less than one percent solids. No organic layer was observed. The 125 mL sample was submitted to the laboratory for analysis of inorganic analytes and radionuclides.

Diaz, L.A.

1998-03-20

270

A Search for Gas-Phase Zirconium in s-process Enriched Planetary Nebulae  

NASA Astrophysics Data System (ADS)

We report results from a search for the ground-state fine-structure line of triply ionized zirconium (Zr) near 8 microns, for several planetary nebulae known to have enhanced abundances of other light neutron-capture elements. The observations were made with the high spectral resolution mid-IR spectrometer TEXES (Lacy et al. 2002, PASP, 114, 153) on the IRTF. Zr, atomic number Z = 40, is part of the “light s-process” peak of nuclei which are synthesized in the region between the H and He-burning shells within AGB stars and mixed into the stellar envelope by dredge-up processes before expulsion of a planetary nebula. The targets included objects for which we have demonstrated that Ge (Z = 32) is enhanced by up to a factor of 5 (Sterling et al. 2005, ApJ, 625, 368), and Kr (Z = 36) is enhanced by factors of up to 10 (Sterling et al. 2006, submitted; Sterling & Dinerstein, in preparation). According to both evolutionary models and observations of Galactic S-type stars, Zr can be even more highly enriched than Ge or Kr, with enrichment factors of up to 20 30 (Busso et al. 2001, ApJ, 557, 802; Vanture & Wallerstein 2002, ApJ, 564, 397). If Zr is present primarily in gaseous form in these planetary nebulae, our failure to detect the mid-IR Zr line sets constraints on a combination of the initial mass of the progenitor stars and the details of the s-process and convective mixing. An alternate interpretation is that much of the Zr, a highly refractory element, is locked up in dust grains that formed in the AGB star’s atmosphere before or during envelope ejection. This research was supported by NSF grants AST 97-31156 and 04-06809.

Dinerstein, Harriet L.; Lacy, J. H.; Sellgren, K.; Sterling, N. C.

2006-12-01

271

Processing and properties of zirconium diboride-based composites  

Microsoft Academic Search

Two zirconium diboride-base composites were produced and characterised. The chosen starting compositions were: 55 wt.% ZrB2+41 wt.%TiB2+4 wt.% Ni and 83 wt.% ZrB2+13 wt.% B4C+4 wt.% Ni. The microstructure and properties of these composites were compared to those of a monolithic ZrB2+4 wt.% Ni material. In all cases, metallic Ni as the sintering aid promoted the formation of the liquid

F Monteverde; A Bellosi; S Guicciardi

2002-01-01

272

Mechanical Properties of Continuous Fiber Reinforced Zirconium Diboride Matrix Composites  

NASA Technical Reports Server (NTRS)

Continuous fiber reinforced zirconium diboride matrix composites, SCS-9a-(RBSiCZrB2)matrix, are being developed for leading edge, rocket nozzle and turbine engine applications. Recently, the composite materials have been characterized for tensile properties to 1250 C, the highest temperature tested. The tensile properties are fiber dominated as the matrix is microcracked on fabrication, but favorable failure characteristic are observed. Compression and shear mechanical testing results will be reported if completed. The effects of fiber volume fraction and matrix density on mechanical properties will be discussed. The target applications of the materials will be discussed. Specific testing being performed towards qualification for these applications will be included.

Stuffle, Kevin; Creegan, Peter; Nowell, Steven; Bull, Jeffrey D.; Rasky, Daniel J. (Technical Monitor)

1995-01-01

273

Synthesis of NASICON-Type Lithium Zirconium Phosphate  

Microsoft Academic Search

The chemical transformations involved in the synthesis of the NASICON-type compound LiZr2(PO4)3 were studied by thermogravimetry and x-ray diffraction. The results demonstrate that, during heat treatment of a 3Zr(HPO4)2 · 2H2O + Li2CO3 + ZrO2 mixture, the formation of the NASICON phase begins at 600°C. Further heating, however, leads to the concurrent formation of zirconium diphosphate and uncontrolled lithium losses

I. A. Stenina; Yu. A. Velikodnyi; V. A. Ketsko; A. B. Yaroslavtsev

2004-01-01

274

Kinetics of formation of a platelet-reinforced ceramic composite prepared by the directed reaction of zirconium with boron carbide  

SciTech Connect

In this paper the kinetics of formation of a new class of ceramic composite material, zirconium diboride platelet-reinforced zirconium carbides, are discussed. These materials are prepared by the directed reaction of molten zirconium with boron carbide to form a ceramic material composed of zirconium diboride platelets approximately uniformly distributed in a zirconium carbide matrix containing a controlled amount of residual zirconium metal. Results from interrupted growth studies, differential thermal analysis, adiabatic reaction temperature calculations, and kinetic measurements have been used to study the kinetics of the process. The reaction is very fast and proceeds parabolically with time with a rate constant between 1.6 {times} 10{sup {minus}2} and 3.9 {times} 10{sup {minus}2} cm{sup 2}/s. The proposed mechanism suggests that when molten zirconium contacts boron carbide, the molten zirconium exothermically reacts with the boron carbide to form a boron-rick liquid. Further reaction is sustained by the continuous dissolution of the boron carbide as the boron-rich liquid is drawn into the boron carbide. The product is a zirconium diboride/zirconium carbide/zirconium composite which homogenizes quickly at the reaction temperature to yield a uniform product microstructure throughout the composite. Two alternative rate-limiting steps are discussed and the implications of each are explored.

Johnson, W.B.; Nagelberg, A.S.; Breval, E. (Lanxide Corp., Newark, DE (US))

1991-09-01

275

34 CFR 97.111 - Criteria for IRB approval of research.  

Code of Federal Regulations, 2011 CFR

... false Criteria for IRB approval of research. 97.111 Section 97.111 Education...Basic ED Policy for Protection of Human Research Subjects) § 97.111 Criteria for IRB approval of research. (a) In order to approve...

2011-07-01

276

34 CFR 97.111 - Criteria for IRB approval of research.  

Code of Federal Regulations, 2010 CFR

... false Criteria for IRB approval of research. 97.111 Section 97.111 Education...Basic ED Policy for Protection of Human Research Subjects) § 97.111 Criteria for IRB approval of research. (a) In order to approve...

2010-07-01

277

34 CFR 97.111 - Criteria for IRB approval of research.  

Code of Federal Regulations, 2013 CFR

... false Criteria for IRB approval of research. 97.111 Section 97.111 Education...Basic ED Policy for Protection of Human Research Subjects) § 97.111 Criteria for IRB approval of research. (a) In order to approve...

2013-07-01

278

34 CFR 97.111 - Criteria for IRB approval of research.  

Code of Federal Regulations, 2012 CFR

... false Criteria for IRB approval of research. 97.111 Section 97.111 Education...Basic ED Policy for Protection of Human Research Subjects) § 97.111 Criteria for IRB approval of research. (a) In order to approve...

2012-07-01

279

Analysis of uranium-zirconium-carbon-oxygen quaternary system for applications in advanced zirconium carbide coated TRISO particles  

NASA Astrophysics Data System (ADS)

The implementation of ZrC for use in oxide TRISO particles for Very High Temperature Reactor (VHTR) conditions to prevent kernel overpressurization and kernel migration has been proposed by several researchers. Analysis is performed incorporating first-principles thermodynamics along with out-of-pile experimental work. UO2+x-U4O9 powders are created and used for in-vacuo thermogravimetric testing with both carbon and zirconium carbide powders to evaluate the efficiency of ZrC for usage as an oxygen getter in oxide TRISO fuels.

Degange, Jonathan Lee

280

97. Historic American Buildings Survey, Donald W. Dickensheets, Photographer. April ...  

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

97. Historic American Buildings Survey, Donald W. Dickensheets, Photographer. April 23, 1940. TOP PEDIMENT - 'GOD THE FATHER'. UPPER NICHE - 'OUR LADY' (B.V.M.) LOWER NICHE - 'ST. FRANCIS XAVIER'. (SOUTH ELEVATION). HIGH ALTAR - San Xavier del Bac Mission, Mission Road, Tucson, Pima County, AZ

281

Annual Report: Doctoral Program Committee, Academic Year 1996-97.  

ERIC Educational Resources Information Center

This document summarizes the activities of the University of California, Los Angeles's (UCLA's) Department of Library and Information Science (DLIS) Doctoral Program Committee, 1996-97. These activities are organized into two main areas: Operations and Students. Doctoral Program Committee (DPC) operations outlined include: preparing major policy…

Lievrouw, Leah A.; Leazer, Greg; Lynch, Beverly; Abler, Susan; Mediavilla, Cynthia

282

What Classroom Teachers Need to Know about IDEA '97  

ERIC Educational Resources Information Center

In the general classroom setting, informed teachers can deliver necessary and appropriate services to students with special needs, while at the same time work toward successful outcomes for those children, their peers, and their parents. IDEA '97 clearly defines educators' responsibilities with regard to children with disabilities, including…

Patterson, Karen

2005-01-01

283

47 CFR 97.309 - RTTY and data emission codes.  

Code of Federal Regulations, 2013 CFR

...specified in this paragraph may use any technique whose technical characteristics have been documented publicly, such as CLOVER, G-TOR, or PacTOR, for the purpose of facilitating communications. (b) Where authorized by §§ 97.305(c) and...

2013-10-01

284

Pennsylvania College of Technology Sourcebook, 1996-97.  

ERIC Educational Resources Information Center

This report provides a statistical profile of Pennsylvania College of Technology (PCT) and its service area for 1996-97. The first two sections provide a profile and history of the college, organizational charts, and a description of the governance system. Section III provides tables on students, including numbers of applications, enrollments, and…

Cunningham, Stephen

285

40 CFR 86.401-97 - General applicability.  

Code of Federal Regulations, 2013 CFR

...Emission Regulations for 1978 and Later New Motorcycles, General Provisions § 86.401-97...model year, new, gasoline-fueled motorcycles built after 31 December, 1977, and...model year, new, methanol-fueled motorcycles built after 31 December, 1989...

2013-07-01

286

97. Reproduction from glass plate negative (Modjeski and Masters office, ...  

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

97. Reproduction from glass plate negative (Modjeski and Masters office, Modjeski Collection, No. 180, May 20, 1908) LOADING BEAMS OF WILLAMETTE BRIDGE DRAW SPAN - Burlington Northern Railroad Bridge, Spanning Willamette River at River Mile 6.9, Portland, Multnomah County, OR

287

Pro Football 97: Sports Illustrated Presents a Preseason Preview  

NSDL National Science Digital Library

The Cable News Network and Sports Illustrated have combined their formidable news gathering, analytic, and photographic talents to provide this site as an enhancement to the CNNSI TV network. A highlight of the site is a selection of articles from Sports Illustrated's Pro Football '97 Preview.

1997-01-01

288

97. Photocopy of drawing (December 1962 architectural drawing by Stevens ...  

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

97. Photocopy of drawing (December 1962 architectural drawing by Stevens & Wilkinson, original in possession of Stevens & Wilkinson, Atlanta, Georgia). First floor plan (and site plan), parking garage addition for Rich's Inc., drawing no. A2-8. - Rich's Downtown Department Store, 45 Broad Street, Atlanta, Fulton County, GA

289

97. POINT SPILL, TWIN FALLS MAIN CANAL, TWIN FALLS COUNTY ...  

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

97. POINT SPILL, TWIN FALLS MAIN CANAL, TWIN FALLS COUNTY NORTHWEST OF MURTAUGH, IDAHO; OVERALL WEST VIEW FROM CANAL SIDE. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

290

Career Program Completers: Class of 1996-97.  

ERIC Educational Resources Information Center

Each year, Johnson County Community College (JCCC, Kansas) conducts follow-up studies of students who completed a JCCC career program during the previous academic year. This report summarizes findings, based on both graduates' and their employers' satisfaction with JCCC, for the follow-up study of the class of 1996-97. Out of a list of 573…

Conklin, Karen A.

291

Texas Public School Dropouts, 1996-97 Report.  

ERIC Educational Resources Information Center

This annual report provides information about dropouts in Texas public schools for the 1996-97 school year. The report includes (1) historical dropout information; (2) a summary of dropout rates based on dropout characteristics and school district characteristics; (3) a listing of dropout rates broken down by county, district, and campus; and (4)…

Texas Education Agency, Austin. Div. of Research and Evaluation.

292

On the accuracy of statistical distributions in Microsoft Excel 97  

Microsoft Academic Search

The paper deals with the numerical accuracy of some statistical functions in Microsoft Excel (Excel version in Microsoft Office 97 for Windows). It is shown that the computation of some discrete distributions (Binomial, Poisson, Hypergeometric) fails even for probabilities in the central range between 0.01 and 0.99 and even for parameter values that cannot be judged as too extreme. Furthermore

Leo Knüsel

1998-01-01

293

Projected FY97 Small Business Innovative Research Topics.  

National Technical Information Service (NTIS)

The topics will appear in the DoD Solicitation FY97.1 that opens on or about 1 October 1996. The purpose of this document is to provide small businesses with an advance copy of ASO's SBIR requirements. It also provides you with an opportunity to discuss t...

1996-01-01

294

STS-97 Crew Interview: Marc Garneau, MS2  

NASA Technical Reports Server (NTRS)

The STS-97 Mission Specialist Marc Garneau is seen being interviewed. He answers questions about his inspiration to become an astronaut, his career path, and his training. He gives details on the mission's goals and significance, its payload, the rendezvous with the International Space Station (ISS), and what it will be like to work knowing there is already a crew on board the ISS.

2000-01-01

295

27 CFR 478.97 - Loan or rental of firearms.  

Code of Federal Regulations, 2011 CFR

...AMMUNITION COMMERCE IN FIREARMS AND AMMUNITION Conduct of Business § 478.97 Loan or rental of firearms. (a) A licensee...association, or similar organization to be engaged in the business of a dealer in firearms or as engaging in firearms...

2011-04-01

296

Layered zirconium phosphonate with inorganic-organic hybrid structure: Preparation and its assembly with DNA  

NASA Astrophysics Data System (ADS)

An aminoethoxy-functionalized zirconium phosphonate (Zr(O3POCH2CH2NH2)2·3H2O), abbreviated as ZrRP (R=OCH2CH2NH2), with layered structure has been synthesized. This layered compound possesses the characteristic of inorganic-organic hybrid, due to the covalently linked aminoethoxy in the host layer. The anion exchanged property of this zirconium phosphonate is suitable for the direct intercalation of negatively charged DNA, which is different from these reported zirconium phosphates or zirconium phosphonates. As a precursor, this prepared zirconium phosphonate was utilized to fabricate a novel DNA/ZrRP binary hybrid via a delamination-reassembly procedure. The release behavior of DNA from the DNA/ZrRP composite was investigated at different medium pH, because the combination between zirconium phosphonate sheets and DNA was pH-dependent sensitively. Moreover, the helical conformation of DNA was almost retained after the intercalation and release process. These properties of the DNA/ZrRP composite suggested the potential application of layered zirconium phosphonate as a non-viral vector in gene delivery.

Liu, Li-Min; Lu, Guo-Yuan; Jiang, Li-Ping; Zhu, Jun-Jie

2014-07-01

297

Growth and structure of zirconium hydrous polymers in aqueous solutions  

SciTech Connect

Zirconium oxychloride solutions prepared at different pH were heated at elevated temperatures for various aging periods to gain an understanding of the growth mechanism and structure of zirconium hydrous polymers. Small angle X-ray scattering (SAXS) measurements were made on these solutions. It was observed that shape of clusters at the earlier stages of growth is close to a rod rather than a sheet as suggested earlier. The scattering data indicate that a rod-shaped primary particle is formed at pH 1.2, and on an increase in the pH, the primary particles become more branched. On aging more than 1,250 min at 92 C, these primary particles form large aggregates while retaining the primary particle structure. These aggregates, which are mass fractal in nature, restructure while growing in size and eventually transform into dense particles. Scattering data in this study were not enough to determine a specific kinetic growth model of the aggregates because the scattering intensity at low q constantly changes with time during the restructuring process.

Singhal, A. [Oak Ridge National Lab., TN (United States)] [Oak Ridge National Lab., TN (United States); [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Chemistry; Toth, L.M.; Lin, J.S. [Oak Ridge National Lab., TN (United States)] [Oak Ridge National Lab., TN (United States); Beaucage, G. [Univ. of Cincinnati, OH (United States). Dept. of Materials Science and Engineering] [Univ. of Cincinnati, OH (United States). Dept. of Materials Science and Engineering; Peterson, J. [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Chemistry] [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Chemistry

1997-10-15

298

MOCVD of zirconium oxide thin films: Synthesis and characterization  

NASA Astrophysics Data System (ADS)

The synthesis of thin films of zirconia often produces tetragonal or cubic phases, which are stable at high temperatures, but that can be transformed into the monoclinic form by cooling. In the present study, we report the deposition of thin zirconium dioxide films by metalorganic chemical vapor deposition using zirconium (IV)-acetylacetonate as precursor. Colorless, porous, homogeneous and well adherent ZrO 2 thin films in the cubic phase were obtained within the temperature range going from 873 to 973 K. The deposits presented a preferential orientation towards the (1 1 1) and (2 2 0) planes as the substrate temperature was increased, and a crystal size ranging between 20 and 25 nm. The kinetics is believed to result from film growth involving the deposition and aggregation of nanosized primary particles produced during the CVD process. A mismatch between the experimental results obtained here and the thermodynamic prediction was found, which can be associated with the intrinsic nature of the nanostructured materials, which present a high density of interfaces.

Torres-Huerta, A. M.; Domínguez-Crespo, M. A.; Ramírez-Meneses, E.; Vargas-García, J. R.

2009-02-01

299

Retrospective Reactor Dosimetry with Zirconium Alloy Samples in a Pwr  

NASA Astrophysics Data System (ADS)

Retrospective measurements are routinely performed with stainless steel samples. Recent experiments have been successfully conducted using zirconium alloy samples, involving somewhat different neutron activation reactions than are normally encountered with stainless steel samples. The sample alloy compositions consisted of ZIRLO which nominally contains about 1.0% (by weight) niobium, 0.65-1.0% tin, and 0.1% iron, with the balance zirconium. The activation products observed in the samples by gamma spectroscopy included Zr-95, Nb-93m, Nb-95, Sn-113, Sb-125, Mn-54, Co-60, Nb-94, and Ta-182. The niobium was then chemically separated following ASTM procedure El297 and the Nb-93m activities were measured by x-ray spectroscopy. The thermal neutron fluences, as determined independently by the neutron capture gamma reactions to Zr-95, Sn-113, Nb-94, and Sn/Sb-125, were in excellent agreement. The fast neutron fluences, as determined separately by the Fe-54(n,p)Mn-54 and Nb-93(n,n')Nb-93m reactions, were also in good agreement, thus demonstrating the versatility of the retrospective dosimetry technique. The results were used to experimentally determine the fast and thermal fluxes in the Vogtle unit 2 PWR.

Greenwood, L. R.; Foster, J. P.

2009-08-01

300

Evidence for an ideal transparent anodic oxide film on zirconium  

SciTech Connect

The properties of a transparent oxide formed on zirconium by anodic oxidation in carbonate buffer are described. The transparent oxide has all the properties of an ideal valve-metal oxide. The film grows via a high field conduction mechanism. The potential and film thickness both increase linearly with time under constant-current growth conditions to well over 100 V with no sign of electronic leakage or breakdown. When the oxide is grown at a current density of 93 {mu}A/cm{sup 2}, the electric field in the oxide is 4.1 MV/cm, and the oxide is anisotropic with n{sub z} = 2.278 parallel and n{sub x} = 2.296 perpendicular to the field. The relative permittivity is 38.3 at the anodizing field, and the oxide shows electrostrictive effects similar to those exhibited by other valve-metal oxides with high relative permittivities. Both the refractive index and the relative permittivity increase when the field is removed, and there is a corresponding decrease in film thickness of just under 1%. Cathodic reduction inserts hydrogen into the oxide to a limited depth, and the outer layer thus formed is optically absorbing. Subsequent anodic oxidation removes the hydrogen and returns the film to its initial transparent state. The present study was carried out as part of an investigation comparing films formed anodically with films formed in steam on zirconium-based reactor tube materials.

Ord, J.L.; Smet, D.J. De [Univ. of Waterloo, Ontario (Canada). Dept. of Physics

1995-03-01

301

Reaction of Titanium and Zirconium Particles in Cylindrical Explosive Charges  

NASA Astrophysics Data System (ADS)

The critical conditions for the reaction of high melting-point metallic particles (Ti, Zr) dispersed during the detonation of long cylindrical explosive charges have been investigated experimentally. The charges consisted of packed beds of either spherical titanium particles (with diameters of 35, 90, or 215 ?m; AP&C, Inc.) or nonspherical zirconium particles (250 -- 500 ?m or 500 -- 600 ?m, Atlantic Equipment Eng., NJ) saturated with sensitized liquid nitromethane. For the titanium particles, a threshold particle diameter exists, above which self-sustained particle reaction is not observed, although some particle reaction occurs immediately behind the detonation front then rapidly quenches. For the smallest particles, the proportion of the conical particle cloud that reacts increases with charge diameter, suggesting that the reaction initiation is a competition between particle heating and expansion cooling of the products. For zirconium particles, no critical conditions exist; particle ignition was observed for all particle and charge diameters tested. In this case, interaction of the high pressure detonation wave with the particles is sufficient to initiate reaction at the particle surface after a delay time (˜ 10's ?s), which is much less than the time required for thermal equilibration of the particles.

Frost, David; Cairns, Malcolm; Goroshin, Samuel; Zhang, Fan

2007-06-01

302

Characterization of SAES St198 zirconium-iron-tin alloy  

SciTech Connect

A waste minimization program to develop a non-oxidative stripper system based on metallic getters is being conducted. Initial development is being performed using a Zr-Fe-Sn intermetallic alloy getter procured as Stl98 from SAES Gefters/USA., Inc. This memorandum describes characterizations of physical and compositional properties of SAES Stl98. SAES Stl98 getter was supplied as very durable, cylindrical pellets made by compaction of. granules of Zr-Fe-Sn alloy up to 150 {mu}m in size. Pellet density was 5.2 g/mL corresponding to 24.8% open porosity and very little closed porosity. Bulk composition of Stl98 was 73.6 weight percent (w/o) Zr, 23.3 w/o Fe and 1.2 w/o Sn. Stl98 consists of Zr{sub 2}Fe primary phase along with four secondary phases (ZrFe{sub 2}, Zr{sub 5}FeSn, {alpha}-zirconium, and {eta}-Zr{sub 4}Fe{sub 2}O{sub 0.6}). Hydriding characteristics of Stl98 are expected to differ slightly from those of Zr{sub 2}Fe because {alpha}-zirconium and, possibly, Zr{sub 5}FeSn also react with hydrogen.

Mosley, W.C.

1992-10-13

303

Characterization of SAES St198 zirconium-iron-tin alloy  

SciTech Connect

A waste minimization program to develop a non-oxidative stripper system based on metallic getters is being conducted. Initial development is being performed using a Zr-Fe-Sn intermetallic alloy getter procured as Stl98 from SAES Gefters/USA., Inc. This memorandum describes characterizations of physical and compositional properties of SAES Stl98. SAES Stl98 getter was supplied as very durable, cylindrical pellets made by compaction of. granules of Zr-Fe-Sn alloy up to 150 [mu]m in size. Pellet density was 5.2 g/mL corresponding to 24.8% open porosity and very little closed porosity. Bulk composition of Stl98 was 73.6 weight percent (w/o) Zr, 23.3 w/o Fe and 1.2 w/o Sn. Stl98 consists of Zr[sub 2]Fe primary phase along with four secondary phases (ZrFe[sub 2], Zr[sub 5]FeSn, [alpha]-zirconium, and [eta]-Zr[sub 4]Fe[sub 2]O[sub 0.6]). Hydriding characteristics of Stl98 are expected to differ slightly from those of Zr[sub 2]Fe because [alpha]-zirconium and, possibly, Zr[sub 5]FeSn also react with hydrogen.

Mosley, W.C.

1992-10-13

304

Dispersion type zirconium matrix fuels fabricated by capillary impregnation method  

NASA Astrophysics Data System (ADS)

Several novel dispersion fuel compositions with a high uranium content fuel (U9Mo, U5Zr5Nb, U 3Si) and a zirconium alloy matrix with low melting point (1063-1133 K) have been developed at A.A. Bochvar Institute using a capillary impregnation fabrication method. The capillary impregnation method introduces fuel granules and granules of a zirconium alloy into a fuel element followed by a short-term anneal at a temperature above the melting temperature of alloy. The alloy melts down and under capillary forces moves into the joints between the fuel element components to form metallurgical bonds. The volume ratios between the components are: 55-65% fuel, 10-20% matrix, and 15-30% pores. Fuel elements produced by capillary impregnation method have a high uranium content (9-10 g cm -3) and a high thermal conductivity (18-22 W m -1 K -1), which, when used as PWR or BWR fuels allow the fuel temperature to be lowered to 723-773 K. They also feature porosity to accommodate swelling. The metallurgical fuel-cladding bond makes the fuel elements serviceable in power transients. The primary advantages for PWR, BWR and CANDU use of these fuels elements, would be the high uranium content, low fuel temperature and serviceability under transient conditions. Consideration is given to their applicability in Floating Nuclear Power Plants (FNPP) as well as for the feasibility of burning civil and weapon grade plutonium.

Savchenko, A.; Konovalov, I.; Vatulin, A.; Morozov, A.; Orlov, V.; Uferov, O.; Ershov, S.; Laushkin, A.; Kulakov, G.; Maranchak, S.; Petrova, Z.

2007-05-01

305

On the mechanisms of carbon monoxide reduction with zirconium hydrides  

SciTech Connect

Results of studies to prepare dinitrogen complexes of zirconium led to the synthesis of a crystalline N/sub 2/ adduct of bis(pentamethylcyclopentadienyl)zirconium, ((eta/sup 5/-C/sub 5/Me/sub 5/)/sub 2/ZrN/sub 2/)/sub 2/N/sub 2/(1), which when treated with CO yielded sequentially ((eta/sup 5/-C/sub 5/Me/sub 5/)/sub 2/Zr(CO))/sub 2/N/sub 2/ and (eta/sup 5/-C/sub 5/Me/sub 5/)/sub 2/Zr(CO)/sub 2/. Reaction of the latter compound with H/sub 2/ was found to proceed according to the reaction (eta/sup 5/-C/sub 5/Me/sub 5/)/sub 2/Zr(CO)/sub 2/ + H/sub 2/ ..-->.. (eta/sup 5/-C/sub 5/Me/sub 5/)/sub 2/Zr(H)(OCH/sub 3/) + CO (2 atm, 110/sup 0/C). Results of studies of the mechanisms of this reaction are reported. Olefins, acetylenes, nitriles, isocyanides, and H/sub 2/, as well as CO, rapidly displace the N/sub 2/ in 1 to yield a variety of stable adducts. Possible mechanisms for these related reactions are also suggested. (BLM)

Wolczanski, P.T.; Bercaw, J.E.

1980-04-01

306

Properties of zirconium carbide for nuclear fuel applications  

NASA Astrophysics Data System (ADS)

Zirconium carbide (ZrC) is a potential coating, oxygen-gettering, or inert matrix material for advanced high temperature reactor fuels. ZrC has demonstrated attractive properties for these fuel applications including excellent resistance against fission product corrosion and fission product retention capabilities. However, fabrication of ZrC results in a range of stable sub-stoichiometric and carbon-rich compositions with or without substantial microstructural inhomogeneity, textural anisotropy, and a phase separation, leading to variations in physical, chemical, thermal, and mechanical properties. The effects of neutron irradiation at elevated temperatures, currently only poorly understood, are believed to be substantially influenced by those compositional and microstructural features further adding complexity to understanding the key ZrC properties. This article provides a survey of properties data for ZrC, as required by the United States Department of Energy's advanced fuel programs in support of the current efforts toward fuel performance modeling and providing guidance for future research on ZrC for fuel applications. Carbon-to-zirconium ratio (the product stoichiometry). Chemical impurities. Presence of secondary phases including grain boundary phases. Grain size, morphology, orientation, and texture. Porosity and pore size, distribution, and morphology. Other forms of defects

Katoh, Yutai; Vasudevamurthy, Gokul; Nozawa, Takashi; Snead, Lance L.

2013-10-01

307

Wear Analysis in THA Utilizing Oxidized Zirconium and Crosslinked Polyethylene  

PubMed Central

Oxidized zirconium, a material with a ceramic surface on a metal substrate, and highly cross-linked polyethylene are two materials developed to reduce wear. We measured in vivo femoral head penetration in patients with these advanced bearings. We hypothesized the linear wear rates would be lower than those published for cobalt-chrome and standard polyethylene. We retrospectively reviewed a select series of 56 THAs in a relatively young, active patient population utilizing oxidized zirconium femoral heads and highly cross-linked polyethylene acetabular liners. Femoral head penetration was determined using the Martell computerized edge-detection method. All patients were available for 2-year clinical and radiographic followup. True linear wear was 4 ?m/year (95% confidence intervals, ± 59 ?m/year). The early wear rates in this cohort of relatively young, active patients were low and we believe justify the continued study of these alternative bearing surfaces. Level of Evidence: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Garvin, Kevin L.; Mangla, Jimmi; Murdoch, Nathan; Martell, John M.

2008-01-01

308

Hydrogen pickup measurements in zirconium alloys: Relation to oxidation kinetics  

NASA Astrophysics Data System (ADS)

The optimization of zirconium-based alloys used for nuclear fuel cladding aims to reduce hydrogen pickup during operation, and the associated cladding degradation. The present study focuses on precisely and accurately measuring hydrogen pickup fraction for a set of alloys to specifically investigate the effects of alloying elements, microstructure and corrosion kinetics on hydrogen uptake. To measure hydrogen concentrations in zirconium alloys two techniques have been used: a destructive technique, Vacuum Hot Extraction, and a non-destructive one, Cold Neutron Prompt Gamma Activation Analysis. The results of both techniques show that hydrogen pickup fraction varies significantly with exposure time and between alloys. A possible interpretation of the results is that hydrogen pickup results from the need to balance charge. That is, the pickup of hydrogen shows an inverse relationship to oxidation kinetics, indicating that, if transport of charged species is rate limiting, oxide transport properties such as oxide electronic conductivity play a key role in the hydrogen pickup mechanism. Alloying elements (either in solid solution or in precipitates) would therefore impact the hydrogen pickup fraction by affecting charge transport.

Couet, Adrien; Motta, Arthur T.; Comstock, Robert J.

2014-08-01

309

Ligand exchange chromatography of free amino acids and proteins on porous microparticulate zirconium oxide  

SciTech Connect

The Lewis acid sites present on the underlying zirconium oxide particles are responsible for the unusual elution sequence for amino acids on copper loaded, phosphated zirconium oxide supports reported in an earlier study. To more thoroughly examine the effect of these strong Lewis acid sites in this paper. The authors have studied ligand exchange chromatography on copper loaded zirconium oxide particles. It is shown here that carboxylate functional groups on amino acid solutes strongly interact with surface Lewis acid sites. Addition of competing hard Lewis bases to the eluent attenuates these specific interactions. The result is a chromatographic system with high selectivity which is also suitable for ligand exchange chromatography of proteins.

Blackwell, J.A. (13M Co., Specialty Adhesives and Chemicals Div., St. Paul, MN (United States)); Carr, P.W. (Dept. of Chemistry, Inst. for Advanced Studies in Bioprocess Technology, Univ. of Minnesota, Minneapolis, MN (United States))

1992-01-01

310

Physicomechanical properties of the surface of a zirconium alloy modified by a pulsed ion beam  

NASA Astrophysics Data System (ADS)

The physicomechanical properties of the surface of the Zr-1% Nb zirconium alloy modified by a pulsed carbon ion beam with a pulse duration of 80 ns, an energy of 200 keV, and a current density of 120 A/cm2 are studied at four regimes having different numbers of pulses. Irradiation by a carbon ion beam results in hardening of the surface layer to a depth of 2 ?m, grain refinement to 0.15-0.8 ?m, zirconium carbide formation, and a decrease in the hydrogen permeability of the zirconium alloy.

Chernov, I. P.; Berezneeva, E. V.; Beloglazova, P. A.; Ivanova, S. V.; Kireeva, I. V.; Lider, A. M.; Remnev, G. E.; Pushilina, N. S.; Cherdantsev, Yu. P.

2014-04-01

311

97. Photographic copy of drawing (14 February 1905, original drawing ...  

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

97. Photographic copy of drawing (14 February 1905, original drawing in Archives, Office of the Building, Administration Building, Sears, Roebuck and Company Mail Order Plant, Chicago, Illinois). Nimmons and Fellows. 1/16 inch to one foot. Section drawings through the first four warehouse bays west of Homan Avenue. TRANSVERSE AND LONGITUDINAL SECTIONS - Sears Roebuck & Company Mail Order Plant, Merchandise Building, 924 South Homan Avenue, Chicago, Cook County, IL

312

97. VIEW OF CENTER OF INTERIOR ROW OF EQUIPMENT CABINETS ...  

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

97. VIEW OF CENTER OF INTERIOR ROW OF EQUIPMENT CABINETS ON SOUTH SIDE OF LANDLINE INSTRUMENTATION ROOM. THREE ADDITIONAL GOULD BRUSH CHART RECORDERS ARE IN THIS ROW (NOT VISIBLE IN PHOTOGRAPH) LOCATED IMMEDIATELY EAST (LEFT) OF THESE CABINETS. Another row of cabinets south of (behind) this one is not accessible for photography. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Operations Building, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

313

97. View of International Business Machine (IBM) digital computer model ...  

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

97. View of International Business Machine (IBM) digital computer model 7090 magnetic core installation, international telephone and telegraph (ITT) Artic Services Inc., Official photograph BMEWS site II, Clear, AK, by unknown photographer, 17 September 1965, BMEWS, clear as negative no. A-6604. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

314

LASE measurements of convective boundary layer development during SGP97  

NASA Technical Reports Server (NTRS)

The Southern Great Plains 1997 (SGP97) field experiment was conducted in Oklahoma during June-July 1997 to validate the models used for computing remote soil moisture using measurements by microwave radiometers. One of the objectives of SGP97 was to examine the effect of soil moisture on the evolution of the Atmospheric Boundary Layer (ABL) and clouds over the Southern Great Plains (SGP) during the warm season. The LASE (Lidar Atmospheric Sensing Experiment) airborne DIAL (Differential Absorption Lidar) system, which was flown autonomously on the NASA ER-2 aircraft during previous missions, was reconfigured to fly on the NASA P3 research aircraft. During SGP97 LASE was used to study the morning evolution of the ABL, particularly as manifested in the development of the convective boundary layer, and to study the influence of soil moisture variations on the development of ABL. The ABL development is strongly influenced by the surface energy budget, which is in turn influenced by soil moisture, mesoscale meteorology, clouds, and solar insolation. LASE data acquired during this mission are being used to study the ABL water vapor budget, the development of the ABL, spatial and temporal variabilities in the ABL, and the meteorological factors that influence the ABL development. This field experiment also permitted comparisons of LASE water vapor measurements with water vapor profiles acquired by radiosondes launched at the DOE (Department of Energy) Atmospheric Radiation Measurement (ARM) Southern Great Plain (SGP) site and at NASA/Wallops Flight Facility, as well as with measurements from other SGP97 aircraft.

Ismail, Syed; Browell, Edward V.; Ferrare, Richard A.; Senff, Christoph; Davis, Kenneth J.a; Lenschow, Donald H.; Kooi, Susan; Brackett, Vince; Clayton, Marian

1998-01-01

315

STS-97 Crew Interview: Joseph Tanner, MS1  

NASA Technical Reports Server (NTRS)

The STS-97 Mission Specialist Joseph Tanner is seen being interviewed. He answers questions about his inspiration to become an astronaut, his career path, and his training. He gives details on the mission's goals and significance, its payload, the rendez-vous with the International Space Station (ISS), and what it will be like to work knowing there is already a crew on board the ISS.

2000-01-01

316

STS-97 Crew Interview: Carlos Noriega, MS3  

NASA Technical Reports Server (NTRS)

The STS-97 Mission Specialist Carlos Noriega is seen being interviewed. He answers questions about his inspiration to become an astronaut, his career path, and his training. He gives details on the mission's goals and significance, its payload, the rendez-vous with the International Space Station (ISS), and what it will be like to work knowing there is already a crew on board the ISS.

2000-01-01

317

Titrimetric Determination of Thiocyanate in Solutions of the Hafnium-Zirconium Separation Process.  

National Technical Information Service (NTIS)

The control of the thiocyanate concentration is necessary during the process of separating hafnium from zirconium by the hexone-thiocyanate method. Said control is carried out by titrimetric determination of thiocyanate in aqueous and organic solutions co...

C. Vazquez M. Botbol M. H. Hernandez

1980-01-01

318

Study of zirconium/stainless steel interface in tubular junctions made by eutectic diffusion.  

National Technical Information Service (NTIS)

Reprocessing plants and pressurized water loops for fuels irradiation have zirconium (or zircaloy) and austenitic stainless steel tubes connected by mean of diffusion bondings. These bondings are achieved by producing an eutectic film at the interface bet...

J. Y. Blanc R. Le Goff P. Regnier

1990-01-01

319

STS-97 Astronaut Tarner Performs Extravehicular Activity (EVA)  

NASA Technical Reports Server (NTRS)

Astronaut Joseph R. Tanner, STS-97 mission specialist, is seen during a session of Extravehicular Activity (EVA), performing work on the International Space Station (ISS). Part of the Remote Manipulator System (RMS) arm and a section of the newly deployed solar array panel are in the background. The primary objective of the STS-97 mission was the delivery, assembly, and activation of the U.S. electrical power system on board the ISS. The electrical power system, which is built into a 73-meter (240-foot) long solar array structure consists of solar arrays, radiators, batteries, and electronics. The entire 15.4-metric ton (17-ton) package is called the P6 Integrated Truss Segment and is the heaviest and largest element yet delivered to the station aboard a space shuttle. The electrical system will eventually provide the power necessary for the first ISS crews to live and work in the U.S. segment. The STS-97 crew of five launched aboard the Space Shuttle Orbiter Endeavor on November 30, 2000 for an 11 day mission.

2000-01-01

320

STS-97 Astronaut Tarner During Extravehicular Activity (EVA)  

NASA Technical Reports Server (NTRS)

In this image, STS-97 astronaut and mission specialist Joseph R. Tanner uses a 35mm camera to expose a photo of his helmet visor during the flight's first space walk. The blue and white planet Earth, some 235 statute miles away, is visible in the left portion of the visor. The primary objective of the STS-97 mission was the delivery, assembly, and activation of the U.S. electrical power system onboard the International Space Station (ISS). The electrical power system, which is built into a 73-meter (240-foot) long solar array structure consists of solar arrays, radiators, batteries, and electronics. The entire 15.4-metric ton (17-ton) package is called the P6 Integrated Truss Segment, and is the heaviest and largest element yet delivered to the station aboard a space shuttle. The electrical system will eventually provide the power necessary for the first ISS crews to live and work in the U.S. segment. The STS-97 crew of five launched aboard the Space Shuttle Orbiter Endeavor on November 30, 2000 for an 11 day mission.

2000-01-01

321

Long-term leaching behaviour of glasses containing zirconium  

NASA Astrophysics Data System (ADS)

Five borosilicate glasses containing up to 20% zirconium oxide and 10% non-radioactive fission products or lanthanum oxide (which simulates the behaviour of the actinides) were leached in stagnant distilled water at 20 ° C for 2 years. The leaching rates of Na, La, Mn, Cs and Mo varied with time and the chemical composition of the glass from 0.7 to 12, 0.006 to 0.14, 0.8 to 1.2, 0.4 to 0.8 and 8 to 25 mg/m 2/d respectively. The glasses which showed the beast short-term resistance do not have the best long-term resistance.

St.-Pierre, Jean; Zikovsky, L.

1984-08-01

322

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

NASA Technical Reports Server (NTRS)

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

2003-01-01

323

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

NASA Technical Reports Server (NTRS)

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

2003-01-01

324

Extraction and spectrophotometric determination of zirconium(IV)  

SciTech Connect

A sensitive and selective method for the extraction and spectrophotometric determination of Zr(IV) with N-p-chlorophenyl-3,4,5-trimethoxycinnamohydroxamic acid (PTCHA) has been developed. The binary complex of Zr(IV)-PTCHA is extracted from 2-6 M HCl into chloroform, having a maximum absorbance at 385 nm; molar absorptivity 2.1 x 10/sup 4/ 1 mol/sup -1/ cm/sup -1/. A ternary complex with xylenol orange (Zr-PTCHA-XO) have been studied in chloroform-ethanol media, which absorbs at 540 nm; molar absorptivity 4.3 x 10/sup 4/ 1 mol/sup -1/ cm /sup -1/. The present method is applied for the analysis of zirconium in standard samples. 15 references, 3 tables.

Agrawal, Y.K.; John, K.T.

1984-01-01

325

Characterization of hemoglobin immobilized on gamma-zirconium phosphate.  

PubMed

The fact that different gamma-zirconium phosphate (gamma-ZrP) preintercalation method induced varied degree and type of conformational change of the adsorption protein was confirmed by characterization techniques including circular dichroism (CD), fourier transform infrared spectroscopy (FTIR) and X-ray powder diffraction (XRD) analysis. The results indicated that the association of hemoglobin with gamma-ZrP preintercalated using butylamine was correlated with conformational change in the secondary structure of the protein. gamma-ZrP which was preintercalated with tetra (n-butylammonium) hydroxide caused the conformational change of Hemoglobin in both the secondary structure and the tertiary structure. X-ray powder diffraction analysis was used to analyze the crystalline structure of the nanocomposites prepared by relamination. The adsorption isotherms of Hemoglobin on different matrices were set up and fitted with Langmuir and Freundlich equations. PMID:15261062

Geng, LiNa; Wang, Xu; Li, Na; Xiang, MingHui; Li, Ke'an

2004-04-15

326

Niobium-Zirconium Chronometry and Early Solar System Development  

NASA Astrophysics Data System (ADS)

Niobium-92 (92Nb) decays to zirconium-92 (92Zr) with a half-life of 36 million years and can be used to place constraints on the site of p-process nucleosynthesis and the timing of early solar system processes. Recent results have suggested that the initial 92Nb/93Nb of the solar system was high (>10-3). We report Nb-Zr internal isochrons for the ordinary chondrite Estacado (H6) and a clast of the mesosiderite Vaca Muerta, both of which define an initial 92Nb/93Nb ratio of ~10-5. Therefore, the solar system appears to have started with a ratio of <3 × 10-5, which implies that Earth's initial differentiation need not have been as protracted as recently suggested.

Schönbächler, Maria; Rehkämper, Mark; Halliday, Alex N.; Lee, Der-Chuen; Bourot-Denise, Michèle; Zanda, Brigitte; Hattendorf, Bodo; Günther, Detlef

2002-03-01

327

Improved tribology of tool steel by zirconium ion implantation  

SciTech Connect

AISI D3 tool steel was ion implanted with zirconium and the improvement in surface tribological properties investigated. The Zr ion implantation was done using a metal vapor vacuum arc broad-beam ion source, with a mean ion energy of 130 keV and at doses of 3.6 x 10(sup 16), 5 x 10(sup 16) and 1 x 10(sup 17) ions/cm2. Wear, friction and hardness of the implanted samples were measured and compared to the performance of unimplanted steel. The wear resistance was increased by about a factor of two, the friction remained about the same or was possibly increased by a small amount, and the hardness was improved by a factor of five or more by the ion implantation. We also investigated the effect on the Zr implantation profile of the multi-component energy distribution of the ion beam used here.

Akbas, N.; Oztarhan, A.; Monteiro, O.R.; Brown, I.G.

2001-02-01

328

Study of nitrogen-rich titanium and zirconium nitride films  

SciTech Connect

Thin titanium nitride (TiN) and zirconium nitride (ZrN) films containing excess nitrogen up to 59 and 63 at. % N, respectively, were deposited on austenitic stainless-steel substrates by reactive triode ion plating at about 823 K. The film structure and surface chemistry were studied using x-ray diffraction, scanning Auger spectroscopy, and electron energy-loss spectroscopy (EELS). In TiN films only the face-centered-cubic mononitride phase was detected. The lattice parameter of the stoichiometric TiN film was larger than the corresponding bulk value and it increased with increasing nitrogen content. The lattice parameter of overstoichiometric ZrN films showed abnormal behavior when calculated from different diffracting planes. This behavior together with the EELS and other measurements indicate that a dielectric Zr/sub 3/N/sub 4/ phase was formed at overstoichiometric compositions.

Ristolainen, E.O.; Molarius, J.M.; Korhonen, A.S.; Lindroos, V.K.

1987-07-01

329

Cavitation at triple nodes in {alpha}-zirconium polycrystals  

SciTech Connect

The damage mechanisms of {alpha}-zirconium polycrystals in tension at room temperature and their dependence on texture and grain size are investigated. Ductile damage proceeds by growth of cavities appearing at triple nodes; at larger strain, other cavities nucleate at precipitate platelets. The cavitation kinetics depend on the tension direction; they are lower the coarser the grains. For a better understanding of the cavity formation at triple nodes, the internal stress field due to intergranular plastic incompatibility is estimated. The mean stress exhibits a logarithmic singularity on the triple junction. By combining this property with some experimentally determined features of the cavity growth (tubular shape along the c axis and growth by activation of prismatic glide), a crystallographic orientation-dependent cavitation criterion is derived. The determination of the grains orientation by the E.B.S.D. technique leads to a satisfactory comparison of the model predictions with the observations.

Care, S.; Zaoui, A. [Ecole Polytechnique, Palaiseau (France). Lab. de Mecanique des Solides] [Ecole Polytechnique, Palaiseau (France). Lab. de Mecanique des Solides

1996-04-01

330

Structure and electronic properties of zirconium and hafnium nitrides and oxynitrides  

Microsoft Academic Search

The atomic structure, stability and electronic properties of zirconium and hafnium nitrides and oxynitrides (MN, M3N4, and M2N2O; M=Zr, Hf) have been studied using first-principles density functional theory calculations. It is found that the orthorhombic Pnam structure of M3N4, which was observed experimentally for zirconium nitride, is more stable for this stoichiometry than the cubic spinel and rock-salt-type structures. The

D. I. Bazhanov; A. A. Knizhnik; A. A. Safonov; A. A. Bagatur'yants; M. W. Stoker; A. A. Korkin

2005-01-01

331

Co-Rolled U10Mo/Zirconium-Barrier-Layer Monolithic Fuel Foil Fabrication Process  

SciTech Connect

Integral to the current UMo fuel foil processing scheme being developed at Idaho National Laboratory (INL) is the incorporation of a zirconium barrier layer for the purpose of controlling UMo-Al interdiffusion at the fuel-meat/cladding interface. A hot “co-rolling” process is employed to establish a ~25-µm-thick zirconium barrier layer on each face of the ~0.3-mm-thick U10Mo fuel foil.

G. A. Moore; M. C. Marshall

2010-01-01

332

DELAYED FAILURE HYDROGEN EMBRITTLEMENT OF ZIRCONIUM. Quarterly Report No. 3, March 15, 1962June 14, 1962  

Microsoft Academic Search

An investigation was made to determine the extent to which zirconium and ;\\u000a zirconium alloys exhibit delayed failure (static fatigue) as caused by a ;\\u000a combination of absorbed hydrogen and applied stress. Evaluation of ;\\u000a susceptibility to time-dependent fracture was performed on an experimental Zr-- ;\\u000a Al-- Sn-- Mo alloy containing 500 ppm hydrogen and the Canadian Zr-2.5Nb cladding ;

D. Weinstein; F. C. Holtz

1962-01-01

333

Mesoporous Zirconium Titanium Oxides. Part 2: Synthesis, Porosity, and Adsorption Properties of Beads  

Microsoft Academic Search

Mesoporous zirconium titanium mixed-oxide beads having disordered wormhole textures and mole fractions of Zr (x) ranging from x = 0.25 to 0.67 have been prepared. The bead preparation method combined the forced hydrolysis of mixtures of zirconium-titanium alkoxides in the presence of long-chain carboxylates with external gelation. Uniformly sized beads could be produced in the size range 0.5--1.1 mm by

G. Devlet Sizgek; Erden Sizgek; Christopher S. Griffith; Vittorio Luca

2009-01-01

334

Ultrafine microsphere particles of zirconium titanate produced by homogeneous dielectric-tuning coprecipitation  

Microsoft Academic Search

Zirconium titanates are widely used in electrical (common microwave dielectrics) and optical devices as well as in bifunctional catalysis and structural ceramics. In this paper, ultrafine amorphous solid microsphere precursor particles of zirconium titanate (ZrxTi1 - xO2) with possibly tailored intraparticle nanostructure (i.e., nanosized pores) were synthesized by a “dielectric-tuning” solution coprecipitation method, in which inorganic salts were dissolved in

Michael Z.-C. Hu; E. A. Payzant; K. R. Booth; C. J. Rawn; R. D. Hunt; L. F. Allard

2003-01-01

335

Solvent Extraction Separation of Zirconium (iv) With Anberlite LA - 1 From Citrate Solutions  

Microsoft Academic Search

Zirconium was quantitatively extracted with 8 × 10 M of Amberlite LA-1 or LA-2 xylene from 0.001 M citric acid at pH 3.5 and it was stripped from the organic phase with 2 M hydrochloric acid and was determined spectrophotometrically at 665 nm as its complex with arsenazo III. Zirconium was separated from binary as well as tertiary mixtures by

C. P. Vibhute; S. M. Khopkar

1983-01-01

336

Features of Preparing Nano-Size Powders of Tetragonal Zirconium Dioxide Stabilized with Yttrium  

Microsoft Academic Search

The effect of wet chemical synthesis parameters on the properties of nano-powders of zirconium dioxide stabilized with yttrium is studied. Features of nano-powder synthesis by the oxalate, hydroxide and thermal hydrolysis of a sol methods are determined. Nano-size zirconium dioxide powder stabilized with 3 mole% yttrium is prepared by hydrothermal coprecipitation from a sol of metal chlorides and urea followed

O. O. Vasylkiv; Y. Sakka; V. V. Skorokhod

2005-01-01

337

Continued Investigation of the Solid-Solid Phase Transitions in Zirconium  

NASA Astrophysics Data System (ADS)

Work has continued to refine and investigate differences in the Hugoniots for Zirconium with differing impurity levels. Past work has shown that interstitial oxygen inhibits the ?->? phase transition but appears to have little effect on the ?->? phase transition. Further plate impact experiments have been carried out to determine differences in the Hugoniots for two of the three types of Zirconium samples studied in previous work.

Rigg, P. A.; Greeff, C. W.; Gray, G. T., III

2011-06-01

338

A novel solid-phase extraction method for separation and preconcentration of zirconium  

Microsoft Academic Search

This work assesses the use of modified natural clinoptilolite as an adsorptive material for separation and preconcentration\\u000a of trace amounts of zirconium ions. A simple, rapid and economical method was developed for the preconcentration of trace\\u000a amounts of zirconium in aqueous medium using 1-(2-pyridylazo)-2-naphthol as a complexing agent. Effect of sample pH, flow\\u000a rate of sample and elution solutions, breakthrough

Hossein Faghihian; Mahboobeh Kabiri-Tadi

2010-01-01

339

Predicting Peri-implant Stresses Around Titanium and Zirconium Dental Implants-A Finite Element Analysis.  

PubMed

Due to anatomical and surgical constrains the implant placement may not be parallel to each other always. Non-parallel implants are subjected to detrimental stresses at implant bone interface. Also depending on type of implant material i.e. titanium or zirconium, stresses tend to vary due to change in physical and mechanical properties. Hence stress analysis at implant bone interface between different parallel and non-parallel implants becomes significant. Evaluation and comparison of stress distribution in the bone around two parallel and non-parallel titanium and zirconium dental implants on axial and non-axial loading supporting three unit fixed prosthesis. Three dimensional finite element models (M1, M2, M3) were made of three differently angulated implants in ANSYS (11.0 Version) software and P4 processor with a speed of 3 GHz and 3 Gb RAM hardware, common for titanium and zirconium implants. Stress around the implants was analyzed on an axial load of 200 N and a non-axial load of 50 N. In both titanium and zirconium implants on axial loading in cortical bone, higher stresses were observed in M3 followed by M2 and M1. On non-axial loading higher stresses were observed in M2, followed by M3 and M1. In both titanium and zirconium implants on axial and non-axial loading in cancellous bone stresses were higher in M3 followed by M2 and M1. Zirconium implants showed lower stresses in cortical bone and higher stresses in cancellous bone compared to titanium implants. Over all Stresses in the bone were more due to titanium implants than zirconium implants. Zirconium implants led to lower peri-implant stresses than titanium implants. PMID:24431734

Gujjarlapudi, Manmohan Choudary; Nunna, Narayana Venkata; Manne, Sanjay Dutt; Sarikonda, Varalakshmi Reddy; Madineni, Praveen Kumar; Meruva, Reddi Narasimha Rao

2013-09-01

340

Porosity occurring in modification of hypoeutectic silumins with strontium and zirconium  

SciTech Connect

The authors investigate modifications in castability, temperature effects, porosity, and fracture properties in silicon-aluminium alloys after being alloyed with strontium and zirconium. The porosity observed in alloys containing strontium was found to have a microshrinkage character. Alloying with zirconium was found to reduce somewhat the tendency of the alloy toward the formation of microshrinkage porosity but did not compensate for the influence of strontium.

Kutsenok, N.L.; Ganiev, I.N.; Yanchuk, V.N.

1987-07-01

341

Ion beam mixing of chromium or zirconium films with sapphire  

SciTech Connect

Ion beam mixing of thin metallic films deposited on sapphire substrates was studied for chromium or zirconium films deposited on single crystalline {alpha}-Al{sub 2}0{sub 3} substrates. Evidence for the influence of equilibrium thermodynamic factors was sought by comparing the effects of bombarding with oxygen ions (300 and 1073 K) with those of neon ions (300 K). Thermodynamic calculations indicate that mixing might occur for Zr/sapphire at 1073 K but not at 300 K. Chromium/sapphire should not be mixed at either temperature. The implantation energy placed the peak oxygen concentration at the metal/sapphire interface in an attempt to maintain an equilibrium ratio of cations/anions and promote a radiation-induced chemical reaction across the interface. Rutherford backscattering-ion channeling measurements indicated that the widths of ``mixed`` regions were consistent with those predicted from ballistic considerations. Other experiments employed a heavier ion (krypton) as the mixing ion (300 K) in order to increase the mixing efficiency. Rutherford backscattering-ion channeling and x-ray photoelectron spectroscopy were used to determine the extent and nature of any interface modification. XPS results indicated that only metallic chromium (Cr{sup 0}) was present near the interface before and after irradiation with Kr at 300 K. Zirconium exhibited only the metallic state (Zr{sup 0}) in the as-deposited film but was present as both Zr{sup 0} and Zr{sup 4{plus}} after irradiation. Some metallic aluminum (AI{sup O}) was detected near the Zr/sapphire interface, suggesting that a local chemical reaction between Zr and the sapphire occurred during bombardment. No long-range material transport was detected for any experimental condition examined; the width of the ``mixed` region in each case was consistent with that expected for ballistic effects.

McHargue, C.J. [Tennessee Univ., Knoxville, TN (United States); Joslin, D.L.; White, C.W. [Oak Ridge National Lab., TN (United States); daSilva, M.F.; Alves, E. [National Inst. for Industrial Technology and Engineering, Sacavem (Portugal); Soares, J.C. [Lisbon Univ. (Portugal)

1995-12-31

342

Mechanical resistance of zirconium implant abutments: A review of the literature  

PubMed Central

The increase of aesthetic demands, together with the successful outcome of current implants, has renewed interest in the search for new materials with enough mechanical properties and better aesthetic qualities than the materials customarily used in implanto-prosthetic rehabilitation. Among these materials, zirconium has been used in different types of implants, including prosthetic abutments. The aim of the present review is to analyse current scientific evidence supporting the use of this material for the above mentioned purposes. We carried out the review of the literature published in the last ten years (2000 through 2010) of in vitro trials of dynamic and static loading of zirconium abutments found in the databases of Medline and Cochrane using the key words zirconium abutment, fracture resistance, fracture strength, cyclic loading. Although we have found a wide variability of values among the different studies, abutments show favourable clinical behaviour for the rehabilitation of single implants in the anterior area. Such variability may be explained by the difficulty to simulate daily mastication under in vitro conditions. The clinical evidence, as found in our study, does not recommend the use of implanto-prosthetic zirconium abutments in the molar area. Key words: Zirconium abutment, zirconium implant abutment, zirconia abutment, fracture resistance, fracture strength, cyclic loading.

Vaquero-Aguilar, Cristina; Torres-Lagares, Daniel; Jimenez-Melendo, Manuel; Gutierrez-Perez, Jose L.

2012-01-01

343

Synthesis, characterization and optical properties of novel N donor ligands-chelated zirconium(IV) complexes  

NASA Astrophysics Data System (ADS)

Novel zirconium complexes have been synthesized by using a mixture of zirconium nitrate, 1,2,4,5-benzen tetracarboxylic acid (H4btec), 1,10-phenanthroline(phen) and potassium thiocyanate. Monodentate coordination mode of btec acid for all complexes was investigated by FT-IR spectroscopy. The complexes were also characterized by UV-Vis, 1H NMR, CHN, ICP-AES. The reaction details and features were described and discussed. The photoluminescence emission of seven zirconium complexes was shown two series peaks: first, sharp and intense bands from 300 to 500 nm and broadened with less intensity from 650 to 750 nm for the second bands. Each of the zirconium compounds were doped in PVK:PBD blend as host. The ratio of zirconium complexes for each type were modified 8 wt.% in PVK:PBD(100:40). The electroluminescence spectra of zirconium complexes were indicated a red shift rather than PVK:PBD blend. We suggest that the electroplex occurring at PVK-Zr complex interface.

Shahroosvand, Hashem; Nasouti, Fahimeh; Mohajerani, Ezeddin; Khabbazi, Amir

2012-11-01

344

Synthesis and characterization of pure cubic zirconium oxide nanocrystals by decomposition of bis-aqua, tris-acetylacetonato zirconium(IV) nitrate as new precursor complex  

Microsoft Academic Search

Pure zirconium oxide (ZrO2) nanocrystals with diameters 10–30nm are fabricated from bis-aqua, tris-acetylacetonato zirconium(IV) nitrate; [Zr(acac)3(H2O)2](NO3); by thermal decomposition. The different combinations of oleylamine, or polyethyleneglycol (PEG) and triphenylphosphine, were added as surfactants to control the particle size. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), ultraviolet–visible (UV–Vis) spectroscopy, photoluminescence spectroscopy (PL), Fourier transform infrared (FT-IR)

Masoud Salavati-Niasari; Mahnaz Dadkhah; Fatemeh Davar

2009-01-01

345

Skeletal Muscle Expression of the Adhesion-GPCR CD97: CD97 Deletion Induces an Abnormal Structure of the Sarcoplasmatic Reticulum but Does Not Impair Skeletal Muscle Function  

PubMed Central

CD97 is a widely expressed adhesion class G-protein-coupled receptor (aGPCR). Here, we investigated the presence of CD97 in normal and malignant human skeletal muscle as well as the ultrastructural and functional consequences of CD97 deficiency in mice. In normal human skeletal muscle, CD97 was expressed at the peripheral sarcolemma of all myofibers, as revealed by immunostaining of tissue sections and surface labeling of single myocytes using flow cytometry. In muscle cross-sections, an intracellular polygonal, honeycomb-like CD97-staining pattern, typical for molecules located in the T-tubule or sarcoplasmatic reticulum (SR), was additionally found. CD97 co-localized with SR Ca2+-ATPase (SERCA), a constituent of the longitudinal SR, but not with the receptors for dihydropyridine (DHPR) or ryanodine (RYR), located in the T-tubule and terminal SR, respectively. Intracellular expression of CD97 was higher in slow-twitch compared to most fast-twitch myofibers. In rhabdomyosarcomas, CD97 was strongly upregulated and in part more N-glycosylated compared to normal skeletal muscle. All tumors were strongly CD97-positive, independent of the underlying histological subtype, suggesting high sensitivity of CD97 for this tumor. Ultrastructural analysis of murine skeletal myofibers confirmed the location of CD97 in the SR. CD97 knock-out mice had a dilated SR, resulting in a partial increase in triad diameter yet not affecting the T-tubule, sarcomeric, and mitochondrial structure. Despite these obvious ultrastructural changes, intracellular Ca2+ release from single myofibers, force generation and fatigability of isolated soleus muscles, and wheel-running capacity of mice were not affected by the lack of CD97. We conclude that CD97 is located in the SR and at the peripheral sarcolemma of human and murine skeletal muscle, where its absence affects the structure of the SR without impairing skeletal muscle function.

Zyryanova, Tatiana; Schneider, Rick; Adams, Volker; Sittig, Doreen; Kerner, Christiane; Gebhardt, Claudia; Ruffert, Henrik; Glasmacher, Stefan; Hepp, Pierre; Punkt, Karla; Neuhaus, Jochen; Hamann, Jorg; Aust, Gabriela

2014-01-01

346

Skeletal Muscle Expression of the Adhesion-GPCR CD97: CD97 Deletion Induces an Abnormal Structure of the Sarcoplasmatic Reticulum but Does Not Impair Skeletal Muscle Function.  

PubMed

CD97 is a widely expressed adhesion class G-protein-coupled receptor (aGPCR). Here, we investigated the presence of CD97 in normal and malignant human skeletal muscle as well as the ultrastructural and functional consequences of CD97 deficiency in mice. In normal human skeletal muscle, CD97 was expressed at the peripheral sarcolemma of all myofibers, as revealed by immunostaining of tissue sections and surface labeling of single myocytes using flow cytometry. In muscle cross-sections, an intracellular polygonal, honeycomb-like CD97-staining pattern, typical for molecules located in the T-tubule or sarcoplasmatic reticulum (SR), was additionally found. CD97 co-localized with SR Ca2+-ATPase (SERCA), a constituent of the longitudinal SR, but not with the receptors for dihydropyridine (DHPR) or ryanodine (RYR), located in the T-tubule and terminal SR, respectively. Intracellular expression of CD97 was higher in slow-twitch compared to most fast-twitch myofibers. In rhabdomyosarcomas, CD97 was strongly upregulated and in part more N-glycosylated compared to normal skeletal muscle. All tumors were strongly CD97-positive, independent of the underlying histological subtype, suggesting high sensitivity of CD97 for this tumor. Ultrastructural analysis of murine skeletal myofibers confirmed the location of CD97 in the SR. CD97 knock-out mice had a dilated SR, resulting in a partial increase in triad diameter yet not affecting the T-tubule, sarcomeric, and mitochondrial structure. Despite these obvious ultrastructural changes, intracellular Ca2+ release from single myofibers, force generation and fatigability of isolated soleus muscles, and wheel-running capacity of mice were not affected by the lack of CD97. We conclude that CD97 is located in the SR and at the peripheral sarcolemma of human and murine skeletal muscle, where its absence affects the structure of the SR without impairing skeletal muscle function. PMID:24949957

Zyryanova, Tatiana; Schneider, Rick; Adams, Volker; Sittig, Doreen; Kerner, Christiane; Gebhardt, Claudia; Ruffert, Henrik; Glasmacher, Stefan; Hepp, Pierre; Punkt, Karla; Neuhaus, Jochen; Hamann, Jörg; Aust, Gabriela

2014-01-01

347

Corrosion susceptibility of EUROFER97 in lithium ceramics breeders  

NASA Astrophysics Data System (ADS)

EUROFER97 specimens were exposed in vacuum to lithium silicate pebbles at 550 °C for up to 2880 h, to evaluate its corrosion susceptibility in a simulated breeder blanket environment. The specimens and pebble bed were then analyzed and characterized by SEM-EDX, XRD, and HR-TEM. The results revealed the formation of a double chromium/iron oxide corrosion layer. HR-TEM also showed that the inner layer was amorphous, while the outer was crystalline. The amorphous layer was brittle, broke easily, and became detached from the steel.

Hernández, Teresa; Fernández, Pilar; Vila, Rafael

2014-03-01

348

STS-97 Crew Activity Report/Flight Day 11 Highlights  

NASA Technical Reports Server (NTRS)

On this eleventh day of the STS-97 mission, Commander Brent W. Jett, Pilot Michael J. Bloomfield, and Mission Specialists Joseph R. Tanner, Carlos I. Noriega, and Marc Garneau remain docked with the International Space Station (ISS) on board the Endeavour Orbiter. Jett and Bloomfield are seen performing a check of the shuttle flight controls in preparation for tomorrow's landing. Jett, Noriega, and Tanner answer questions about the mission and the goals fulfilled. Footage shows the Earth at night as the camera on Endeavour sweeps the Mediterranean coastline, outlined by city lights, showing Spanish/French border, the French Riviera, the Alps, Italy, Switzerland, and the German/Austrian border.

2000-01-01

349

STS-97 Astronaut Tarner During Extravehicular Activity (EVA)  

NASA Technical Reports Server (NTRS)

In this image, planet Earth, some 235 statute miles away, forms the back drop for this photo of STS-97 astronaut and mission specialist Joseph R. Tanner, taken during the third of three space walks. The mission's goal was to perform the delivery, assembly, and activation of the U.S. electrical power system onboard the International Space Station (ISS). The electrical power system, which is built into a 73-meter (240-foot) long solar array structure consists of solar arrays, radiators, batteries, and electronics. The entire 15.4-metric ton (17-ton) package is called the P6 Integrated Truss Segment, and is the heaviest and largest element yet delivered to the station aboard a space shuttle. The electrical system will eventually provide the power necessary for the first ISS crews to live and work in the U.S. segment. The STS-97 crew of five launched aboard the Space Shuttle Orbiter Endeavor on November 30, 2000 for an 11 day mission.

2000-01-01

350

Improved Detection of Mutated Human Cytomegalovirus UL97 by Pyrosequencing? †  

PubMed Central

Ganciclovir (GCV) resistance frequently occurs upon prolonged treatment of ongoing active human cytomegalovirus (HCMV) infection in individuals with immature or compromised immune functions (e.g., recipients of solid-organ and hematopoietic stem cell transplants). Using pyrosequencing (PSQ), we established fast and sensitive detection of GCV resistance-associated mutations occurring in the HCMV open reading frame UL97. These mutations have been repeatedly associated with clinical treatment failure. We designed four PSQ assays and evaluated them by analyzing mixtures of plasmids or bacterial artificial chromosome-derived viruses containing UL97 wild-type and mutant sequences. A minimum level of 6% mutant sequence variants could be detected in these mixtures. In order to further evaluate the novel PSQ assays, we tested clinical specimens from patients with active HCMV infections. The results were compared with those obtained by conventional dideoxy chain terminator sequencing. As the PSQ method was more sensitive in detecting minor HCMV mutant fractions in a wild-type population, it is suggested that pyrosequencing is a useful tool for the early detection of emerging GCV-resistant HCMV in GCV-treated patients.

Schindele, Birgit; Apelt, Luise; Hofmann, Jorg; Nitsche, Andreas; Michel, Detlef; Voigt, Sebastian; Mertens, Thomas; Ehlers, Bernhard

2010-01-01

351

Neutron Capture Measurements on 97Mo with the DANCE Array  

NASA Astrophysics Data System (ADS)

Neutron capture is a process that is crucial to understanding nucleosynthesis, reactors, and nuclear weapons. Precise knowledge of neutron capture cross-sections and level densities is necessary in order to model these high-flux environments. High-confidence spin and parity assignments for neutron resonances are of critical importance to this end. For nuclei in the A=100 mass region, the p-wave neutron strength function is at a maximum, and the s-wave strength function is at a minimum, producing up to six possible Jpi combinations. Parity determination becomes important to assigning spins in this mass region, and the large number of spin groups adds complexity to the problem. In this work, spins and parities for 97Mo resonances are assigned, and best fit models for photon strength function and level density are determined. The neutron capture-cross section for 97Mo is also determined, as are resonance parameters for neutron energies ranging from 16 eV to 2 keV.

Walker, Carrie L.

352

THE SPECTROCHEMICAL DETERMINATION OF RESIDUAL HAFNIUM IN ZIRCONIUM AN ZIRCONIUM ALLOYS USING D.C. ARC EXCITATION AND A BARIUM FLUORIDE FLUX  

Microsoft Academic Search

This method is used to determine residual hafnium in zirconium and ; Zircaloy from 30 parts per million up to 300 parts per million. By selection of ; suitable line pairs the method may be extended to include other concentration ; ranges. The oxidized sample is mixed with a one-to-one barium fluoride -graphite ; mixture and pressed into a 1\\/4

G. J. Harter; R. F. Farrell

1958-01-01

353

Highly enantioselective zirconium-catalyzed cyclization of aminoalkenes.  

PubMed

Aminoalkenes are catalytically cyclized in the presence of cyclopentadienylbis(oxazolinyl)borato group 4 complexes {PhB(C5H4)(Ox(R))2}M(NMe2)2 (M = Ti, Zr, Hf; Ox(R) = 4,4-dimethyl-2-oxazoline, 4S-isopropyl-5,5-dimethyl-2-oxazoline, 4S-tert-butyl-2-oxazoline) at room temperature and below, affording five-, six-, and seven-membered N-heterocyclic amines with enantiomeric excesses of >90% in many cases and up to 99%. Mechanistic investigations of this highly selective system employed synthetic tests, kinetics, and stereochemistry. Secondary aminopentene cyclizations require a primary amine (1-2 equiv vs catalyst). Aminoalkenes are unchanged in the presence of a zirconium monoamido complex {PhB(C5H4)(Ox(4S-iPr,Me2))2}Zr(NMe2)Cl or a cyclopentadienylmono(oxazolinyl)borato zirconium diamide {Ph2B(C5H4)(Ox(4S-iPr,Me2))}Zr(NMe2)2. Plots of initial rate versus [substrate] show a rate dependence that evolves from first-order at low concentration to zero-order at high concentration, and this is consistent with a reversible substrate-catalyst interaction preceding an irreversible step. Primary kinetic isotope effects from substrate conversion measurements (k'obs((H))/k'obs((D)) = 3.3 ± 0.3) and from initial rate analysis (k2((H))/k2((D)) = 2.3 ± 0.4) indicate that a N-H bond is broken in the turnover-limiting and irreversible step of the catalytic cycle. Asymmetric hydroamination/cyclization of N-deutero-aminoalkenes provides products with higher optical purities than obtained with N-proteo-aminoalkenes. Transition state theory, applied to the rate constant k2 that characterizes the irreversible step, provides activation parameters consistent with a highly organized transition state (?S(++) = -43(7) cal·mol(-1) K(-1)) and a remarkably low enthalpic barrier (?H(++) = 6.7(2) kcal·mol(-1)). A six-centered, concerted transition state for C-N and C-H bond formation and N-H bond cleavage involving two amidoalkene ligands is proposed as most consistent with the current data. PMID:23631736

Manna, Kuntal; Everett, William C; Schoendorff, George; Ellern, Arkady; Windus, Theresa L; Sadow, Aaron D

2013-05-15

354

Cesium Adsorption on the ZIRCONIUM/OXYGEN/TUNGSTEN(100) Surface.  

NASA Astrophysics Data System (ADS)

Interest in zirconium covered tungsten as an electrode material has been stimulated by recent work on the model surface Zr/O/W(100). This surface has been shown to have an effective thermionic work function of (TURN) 2.6 eV, when properly prepared, with very low volatility and excellent thermal stability. For advanced thermionic converter applications and for proposed future nuclear electric propulsion systems, the emitter requirement is (phi)(,eff) (LESSTHEQ) 2.4 eV at 1600 K. The corresponding collector must have a work function <(, )1.4 eV at (TURN) 600 K. For any electrode materials yet studied, these requirements dictate the presence of an equilibrium pressure of cesium vapor. The adsorption/desorption characteristics of cesium in the Zr/O/W(100) surface and the effect of cesium coverage on the surface work function have been studied, using Auger electron spectrometry (AES), field emission retarding potential work function measurements (FERP) and thermal desorption mass spectrometry (TDS). The minimum work function attained for cesium adsorption on the Zr/O/W(100) surface was 2.12 eV. The desorption spectrum of cesium from this surface shows major binding states at 1.1 and 1.3 eV, with desorption complete at T (LESSTHEQ) 900 K. Adsorption of excess oxygen on the low work function Zr/O/W(100) surface increases the affinity of the surface toward cesium and lowers the minimum work function. Cesium adsorbed on a saturated layer of excess oxygen shows a terminal desorption temperature of 1300 K and minimum work function of 1.37 eV. Thermal equilibrium of the excess oxygen removes some oxygen and zirconium from the surface, changing the cesium adsorption characteristics. Measurement of low energy electron reflection from the Zr/O/W(100) surface with and without adsorbed cesium indicates that the presence of cesium reduces the reflection coefficient of Zr/O/W(100) near the threshold beam potential for current collection. Two adsorption sites for Cs adsorption on clear W(100) were found in the thermal desorption spectra. The Cs/W(100) bonding is stronger than the bonding of Cs on Zr/O/W(100) surface.

Chen, Hsiung-Ku.

355

Synthesis and liquid crystal phase transitions of zirconium phosphate disks  

NASA Astrophysics Data System (ADS)

Solvent-mediated self-assembly of nanoparticles is an effective and efficient way for the bottom-up organization of functional structures. The primary object of this work is to build up a model system for the study of suspensions of disk-shaped nanoparticles, and use it for the study of self-assembly and discotic liquid crystal phase transitions of discotic particles. The work was introduced by the control over the size and polydispersity of zirconium phosphate (ZrP) disks through synthesis. Systematic experiments revealed that regular-shaped alpha-zirconium phosphate crystalline disks with a size-to-thickness ratio from 1 to 50 and size polydispersity as low as 0.2 can be obtained through hydrothermal treatment in 3 M to 15 M phosphoric acid solutions. Transmission and scanning electron micrographs revealed that the growth of the disks is mediated by oriented attachment, which happened continuously throughout the hydrothermal treatment between various sized disks. Ostwald ripening is effective in improving the regularity of the shape of the disks, especially under prolonged hydrothermal treatment. Under the microwave assisted hydrothermal conditions, the rate of attachment on the flat surfaces of the disks is accelerated, which leads to the formation of the column-shaped crystals. With the ability to adjust the size, aspect ratio, and polydispersity of ZrP disks, the study on self-assembly behavior and the discotic liquid crystal phases was enabled. Firstly, liquid crystal phases of aqueous suspensions of ZrP disks were investigated. Iridescent smectic phase and the critical points of phase transitions were found. Moreover, monolayer ZrP nanosheets with extremely high aspect ratio, which were achieved by exfoliating the ZrP crystals, were also used in this study. The high aspect ratio of nanosheets produces a laminar phase at low nanosheet concentration. Chiral liquid crystal phases were demonstrated when increased the concentration of the nanosheets. The competition between the chirality and layering leads to twisted and layered structures. For the final part, solvent-mediated self-assembly of disks and nanosheets via undulation of liquid crystal phases showed an interesting approach for bottom-up design of functional nano-structures.

Shuai, Min

356

A comparative study of zirconium and titanium implants in rat: osseointegration and bone material quality.  

PubMed

Permanent metal implants are widely used in human medical treatments and orthopedics, for example as hip joint replacements. They are commonly made of titanium alloys and beyond the optimization of this established material, it is also essential to explore alternative implant materials in view of improved osseointegration. The aim of our study was to characterize the implant performance of zirconium in comparison to titanium implants. Zirconium implants have been characterized in a previous study concerning material properties and surface characteristics in vitro, such as oxide layer thickness and surface roughness. In the present study, we compare bone material quality around zirconium and titanium implants in terms of osseointegration and therefore characterized bone material properties in a rat model using a multi-method approach. We used light and electron microscopy, micro Raman spectroscopy, micro X-ray fluorescence and X-ray scattering techniques to investigate the osseointegration in terms of compositional and structural properties of the newly formed bone. Regarding the mineralization level, the mineral composition, and the alignment and order of the mineral particles, our results show that the maturity of the newly formed bone after 8 weeks of implantation is already very high. In conclusion, the bone material quality obtained for zirconium implants is at least as good as for titanium. It seems that the zirconium implants can be a good candidate for using as permanent metal prosthesis for orthopedic treatments. PMID:24170339

Hoerth, Rebecca M; Katunar, María R; Gomez Sanchez, Andrea; Orellano, Juan C; Ceré, Silvia M; Wagermaier, Wolfgang; Ballarre, Josefina

2014-02-01

357

Increased force simulator wear testing of a zirconium oxide total knee arthroplasty.  

PubMed

Total knee replacements provide cost effective treatment for debilitating conditions such as osteoarthritis. Their long term performance is governed by ultra-high molecular weight polyethylene (UHMWPE) wear which produces wear debris leading to osteolysis and aseptic loosening of the implant. An oxidised zirconium alternative to cobalt chrome is being used to reduce wear debris formation in the younger patients. Two TKRs of cobalt chrome and two of zirconium oxide coated zirconium were tested in a six degrees of freedom of motion, Stanmore-Instron force controlled knee wear simulator over 4 million increased force cycles. Oxidised zirconium was demonstrated to be more scratch resistant than CoCr. Increases in Ra (mean average roughness) of 12-fold compared to 1.9 fold rise for ZrO. The differences in roughness were accompanied by a 78%, statistically significant, reduction in wear of UHMWPE with the ZrO femoral components compared to the CoCr (p=0.037). Long term clinical results from the use of oxidised zirconium femoral components are awaited. However, it shows potential to reduce the wear rate. PMID:19321347

Lee, Joshua K L; Maruthainar, Kunalan; Wardle, Nic; Haddad, Fares; Blunn, Gordon W

2009-08-01

358

Separation of hafnium from zirconium in sulfuric acid solutions using pressurized ion exchange  

SciTech Connect

High-resolution pressurized ion exchange has been used successfully to study and separate hafnium and zirconium sulfate complexes by chromatographic elution from Dowex 50W-X8 (15 to 25 ..mu..m) resin with sulfuric acid solutions. Techniques were developed to continuously monitor the column effluents for zirconium and hafnium by reaction with fluorometric and colorimetric reagents. Since neither reagent was specific for either metal ion, peak patterns were initially identified by using the stable isotopes /sup 90/Zr and /sup 180/Hf as fingerprints of their elution position. Distribution ratios for both zirconium and hafnium decrease as the inverse fourth power of the sulfuric acid concentration below 2N and as the inverse second power at higher acid concentration. The hafnium-to-zirconium separation factor is approximately constant (approx. 8) over the 0.5 to 3N range. Under certain conditions, an unseparated fraction was observed that was not retained by the resin. The amount of this fraction which is thought to be a polymeric hydrolysis product appears to be a function of metal and sulfuric acid concentrations. Conditions are being sought to give the highest zirconium concentration and the lowest acid concentration that can be used as a feed material for commercial scale-up in the continuous annular chromatographic (CAC) unit without formation of the polymer.

Hurst, F.J.

1981-01-01

359

Emulsions stabilized by precipitates of zirconium and tributyl phosphate degradation products  

SciTech Connect

In the Purex process, a solvent extraction method of nuclear fuel reprocessing, a stable emulsion called crud forms at the interface between the oil and water phases. This paper reports that crud is an emulsion stabilized by finely dispersed solids. Insoluble residues and precipitates of zirconium and radiation-degraded products of tributyl phosphate (TBP) are key materials in crud formation. Cruds formed by precipitates of zirconium and TBP degradation products, such as di-n-butyl phosphate (HDBP), mono-n-butyl phosphate (H{sub 2}MBP), and phosphoric acid (H{sub 3}PO{sub 4}) are studied. Experimental results show that the precipitate of zirconium and HDBP is not effective in stabilizing emulsions. However, the refractory complex of zirconium and H{sub 3}PO{sub 4} is an important material for stabilizing an oil-in-water emulsion in a solution with or without uranium. Moreover, it is shown that the complex of zirconium and H{sub 2}MBP has a significant role in stabilizing a water-in-oil emulsion, especially when uranium is also present.

Sugai, H.; Munakata, K. (Sumitomo Metal Mining Co., Ltd., Tokai Research Center 2600, Ishigamitojuku, Tokai-mura, Ibaraki-ken 319-11 (JP)); Miyachi, S.; Yasu, S. (Power Reactor and Nuclear Fuel Development Corp., Tokai Works Reprocessing Plant, Analysis Section, Tokai-mura, Ibaraki-ken 319-11 (JP))

1992-05-01

360

Determination of trace iron in zirconium by isotope dilution-thermal ionization mass spectrometry  

NASA Astrophysics Data System (ADS)

An isotope dilution-thermal ionization mass spectrometry method for the determination of parts-per-million levels of iron in zirconium is required for precise, accurate analyses in studies of the effects of iron on the irradiation deformation of nuclear alloys. A two-stage purification procedure was developed to avoid the signal suppression and interference caused by the zirconium matrix. After sample dissolution and spiking with 54Fe, the bulk of the zirconium is removed by ion exchange chromatography, and the eluted Fe(III) is further purified by micro-solvent extraction into tributyl phosphate-impregnated resin beads. The iron is back-extracted, submicrogram amounts are loaded onto previously outgassed zone-refined Re filaments, and 54/56 ratios are measured at 1170°C. A silica gel/boric acid ionization enhancer is used to obtain stable Fe+ currents as strong as 2 × 10-14. A from nanogram loadings of pure iron. The procedural blank of 20 ± 6 ng is sufficiently low to allow determination of ppm levels of iron in 0.1 g zirconium samples. The analyses of solution standards showed agreement within 2% between measured and expected values, and a good fit, r2 = 0.99997, to a linear regression. The analyses of metal standards exhibited a similar good fit to a linear regression of measured against expected values, and showed good agreement with other methods. The method meets the requirements for zirconium metallurgical studies, and may be extended to other applications.

Elliot, N. L.; Campbell, M. A.; Green, L. W.

1995-08-01

361

Zirconium extraction into octyl(phenyl)-N,N-diisobutylcarbamoylmethyl phosphine oxide and tributyl phosphate  

SciTech Connect

Classical slope analysis techniques were used to determine the octyl(phenyl)-N,N-diisobutylcarbamoylmethyl phosphine oxide (CMPO) and nitrate stoichiometries for the extraction of zirconium by CMPO diluted with diisopropylbenzene (DIPB). The equilibrium constant for the extraction of zirconium by CMPO was also determined using classical slope analysis techniques. The extraction of zirconium by TBP in n-dodecane was used as a control to verify the zirconium species as Zr{sup +4}, and to verify the experimental methodology. Equilibrium [CMPO]{sub org} and [TBP]{sub org} concentrations were determined by accounting for the extraction of HNO{sub 3} into both TBP and CMPO solvents. Nitric acid dissociation and aqueous phase activity coefficients were also taken into consideration. Organic activity coefficients, Zr{sup +4} activity coefficients, Zr{sup +4} hydrolysis, and consumption of TBP or CMPO by water were neglected. Nitrate and CMPO dependencies for the extraction of zirconium have been determined from this work to be: Zr{sub aq}{sup +4} + 4 NO{sub 3 aq}{sup {minus}} + 2 CMPO{sub org} {r_arrow} Zr(NO{sub 3}){sub 4} {sm_bullet} 2 CMPO{sub org}. An equilibrium constant of 1.13 {times} 10{sup 5} {+-} 1.48 {times} 10{sup 4} at 25 C was also determined for this reaction.

Brewer, K.N.; Herbst, R.S.; Todd, T.A.; Christian, J.D. [Lockheed Idaho Technologies Co., Idaho Falls, ID (United States)

1998-07-01

362

Synthesis of zirconium tungstate-zirconia core-shell composite particles  

SciTech Connect

Highlights: {yields} ZrW{sub 2}O{sub 8}-ZrO{sub 2} core-shell particles to offer solutions for sintering problems. {yields} Core synthesis by a precursor based on tungstic acid and zirconium acetate. {yields} Shell phase by urea hydrolysis in the presence of zirconium ions. {yields} [Urea]/[ZrOCl{sub 2}] ratio controls the rate of shell precursor precipitation. -- Abstract: In this work, ZrW{sub 2}O{sub 8}-ZrO{sub 2} core-shell composite particles were synthesized. ZrW{sub 2}O{sub 8} that was used in the core is a material with negative coefficient of thermal expansion, and it was synthesized from a high-pH precursor based on use of tungstic acid and zirconium acetate. Shell layer was composed of ZrO{sub 2} nanocrystallites and precipitated from an aqueous solution by urea hydrolysis. While volume of the shell was effectively controlled by the initial zirconium ion concentration in the solutions, the rate of precipitation was a function of the ratio of initial concentrations of urea to zirconium ions. It is hypothesized that isolation of the ZrW{sub 2}O{sub 8} within a layer of ZrO{sub 2}, will be a key element in solving problems associated with reactivity of ZrW{sub 2}O{sub 8} towards other components in sintering of ceramic-ceramic composites with tuned or zero thermal expansion coefficient.

Khazeni, Nasser, E-mail: khazeni.n@gmail.com [Chemical Engineering Department, Middle East Technical University, Ankara 06531 (Turkey)] [Chemical Engineering Department, Middle East Technical University, Ankara 06531 (Turkey); Mavis, Bora, E-mail: bmavis@hacettepe.edu.tr [Mechanical Engineering Department, Hacettepe University, Beytepe Ankara 06800 (Turkey)] [Mechanical Engineering Department, Hacettepe University, Beytepe Ankara 06800 (Turkey); Guenduez, Guengoer, E-mail: ggunduz@metu.edu.tr [Chemical Engineering Department, Middle East Technical University, Ankara 06531 (Turkey)] [Chemical Engineering Department, Middle East Technical University, Ankara 06531 (Turkey); Colak, Uner, E-mail: ucolak@hacettepe.edu.tr [Nuclear Engineering Department, Hacettepe University, Beytepe Ankara 06800 (Turkey)] [Nuclear Engineering Department, Hacettepe University, Beytepe Ankara 06800 (Turkey)

2011-11-15

363

Preparation, characterization and adsorption behavior of tannin-modified poly(glycidylmethacrylate)-grafted zirconium oxide-densified cellulose for the selective separation of bovine serum albumin.  

PubMed

Bovine serum albumin (BSA) is one of the major constituents of blood plasma and its recovery is a significantly useful subject for biomedical applications. In this study, a novel adsorbent, tannin-modified poly(glycidylmethacrylate)-grafted zirconium oxide-densified cellulose (TMPGZDC) was synthesized by graft copolymerization reaction of glycidylmethacrylate onto zirconium oxide-densified cellulose (ZDC) in the presence of N,N'-methylenebisacrylamide as cross-linker followed by tannin immobilization. The adsorbent was characterized using TG, XRD, SEM/EDS, FTIR and fluorescence analyses. The efficiency of the TMPGZDC to adsorb BSA from aqueous solutions was studied at different optimized conditions. The optimum pH for maximum adsorption was found to be 4.8 with the adsorption percentage of 97.8% for an initial concentration of 100 mg/L. Equilibrium was achieved within 30 min. The kinetic data were found to follow pseudo-first-order model which is based on solid capacity. The well agreement of equilibrium data with Langmuir isotherm and Redlich-Peterson isotherm models confirms the monolayer coverage of BSA onto TMPGZDC surface and the maximum adsorption capacity at 30°C was found to be 93.11 mg/g. Thermodynamic study revealed an exothermic adsorption process. TMPGZDC was found to be efficient in the selective adsorption of proteins. Spent adsorbent was effectively regenerated [correction of degenerated] with 0.1 M NaCl. The present investigation shows that TMPGZDC is a promising adsorbent for the recovery of BSA from aqueous solutions and protein mixtures. PMID:22230358

Anirudhan, Thayyath Sreenivasan; Rejeena, Sylaja Raveendran; Tharun, Abdul Rauf

2012-05-01

364

46 CFR 56.97-38 - Initial service leak test (reproduces 137.7).  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Initial service leak test (reproduces 137.7). 56.97-38... § 56.97-38 Initial service leak test (reproduces 137.7). (a) An initial service leak test and inspection is acceptable...

2010-10-01

365

40 CFR 81.97 - Southwest Florida Intrastate Air Quality Control Region.  

Code of Federal Regulations, 2013 CFR

... false Southwest Florida Intrastate Air Quality Control Region. 81.97 Section 81...CONTINUED) DESIGNATION OF AREAS FOR AIR QUALITY PLANNING PURPOSES Designation of Air Quality Control Regions § 81.97 Southwest...

2013-07-01

366

46 CFR 56.97-38 - Initial service leak test (reproduces 137.7).  

Code of Federal Regulations, 2010 CFR

...2009-10-01 false Initial service leak test (reproduces 137.7). 56.97-38... § 56.97-38 Initial service leak test (reproduces 137.7). (a) An initial service leak test and inspection is acceptable...

2009-10-01

367

34 CFR 97.118 - Applications and proposals lacking definite plans for involvement of human subjects.  

Code of Federal Regulations, 2013 CFR

...proposals lacking definite plans for involvement of human subjects. 97.118 Section 97.118...Secretary, Department of Education PROTECTION OF HUMAN SUBJECTS Federal Policy for the Protection of Human Subjects (Basic ED Policy for...

2013-07-01

368

34 CFR 97.119 - Research undertaken without the intention of involving human subjects.  

Code of Federal Regulations, 2013 CFR

...undertaken without the intention of involving human subjects. 97.119 Section 97.119...Secretary, Department of Education PROTECTION OF HUMAN SUBJECTS Federal Policy for the Protection of Human Subjects (Basic ED Policy for...

2013-07-01

369

46 CFR 97.30-1 - Repairs to boilers and pressure vessels.  

Code of Federal Regulations, 2013 CFR

... 2013-10-01 false Repairs to boilers and pressure vessels. 97.30-1...Equipment § 97.30-1 Repairs to boilers and pressure vessels. (a) Before making any repairs to boilers or unfired pressure vessels, the...

2013-10-01

370

Science and Engineering Degrees, by Race/Ethnicity of Recipients: 1989-97  

NSF Publications Database

Science and Engineering Degrees, by Race/Ethnicity of Recipients: 1989-97 Detailed Statistical ... Science and Engineering Degrees, by Race/Ethnicity of Recipients: 1989-97 Portable Document Format ...

371

SURFACE MODIFICATION OF ZIRCALOY-4 SUBSTRATES WITH NICKEL ZIRCONIUM INTERMETALLICS  

SciTech Connect

Surfaces of Zircaloy-4 (Zr-4) substrates were modified with nickel-zirconium (NiZr) intermetallics to tailor oxidation performance for specialized applications. Surface modification was achieved by electroplating Zr-4 substrates with nickel (Ni) and then performing thermal treatments to fully react the Ni plating with the substrates, which resulted in a coating of NiZr intermetallics on the substrate surfaces. Both plating thickness and thermal treatment were evaluated to determine the effects of these fabrication parameters on oxidation performance and to identify an optimal surface modification process. Isothermal oxidation tests were performed on surface-modified materials at 290°, 330°, and 370°C under a constant partial pressure of oxidant (i.e., 1 kPa D2O in dry Ar at 101 kPa) for 64 days. Test results revealed an enhanced, transient oxidation rate that decreased asymptotically toward the rate of the Zr-4 substrate. Oxidation kinetics were analyzed from isothermal weight gain data, which were correlated with microstructure, hydrogen pickup, strength, and hardness.

Luscher, Walter G.; Gilbert, Edgar R.; Pitman, Stan G.; Love, Edward F.

2013-02-01

372

Surface modification of Zircaloy-4 substrates with nickel zirconium intermetallics  

NASA Astrophysics Data System (ADS)

Surfaces of Zircaloy-4 (Zr-4) substrates were modified with nickel-zirconium (NiZr) intermetallics to tailor oxidation performance for specialized applications. Surface modification was achieved by electroplating Zr-4 substrates with nickel (Ni) and then performing thermal treatments to fully react the Ni plating with the substrates, which resulted in a coating of NiZr intermetallics on the substrate surfaces. Both plating thickness and thermal treatment were evaluated to determine the effects of these fabrication parameters on oxidation performance and to identify an optimal surface modification process. Isothermal oxidation tests were performed on surface-modified materials at 290°, 330°, and 370 °C under a constant partial pressure of oxidant (i.e., 1 kPa D2O in dry Ar at 101 kPa) for 64 days. Test results revealed an enhanced, transient oxidation rate that decreased asymptotically toward the rate of the Zr-4 substrate. Oxidation kinetics were analyzed from isothermal weight gain data, which were correlated with microstructure, hydrogen pickup, strength, and hardness.

Luscher, Walter G.; Gilbert, Edgar R.; Pitman, Stan G.; Love, Edward F.

2013-02-01

373

Glucose sensor based on glucose oxidase immobilized by zirconium phosphate.  

PubMed

Amperometric glucose sensors were fabricated using glucose oxidase (GOx) entrapped in zirconium hydrogenphosphate (ZrP), and their performance was evaluated. Reportedly, alpha-ZrP is one of the candidates that are expected to improve the stability of enzymes immobilized on solid surfaces. We intercalated GOxs into ZrP (GOx/ZrP), cast the GOx/ZrP suspension in polyvinylalcohol on a platinum electrode, and dried it in a vacuum oven. The morphological layered structure was investigated by scanning electron microscopy. The enzymatic activities, which were determined by open-circuit potentiometric technique, reached the highest when GOxs were immobilized in ZrP at ca. pH 5. In vitro tests showed good linear responses in the 0-25 mM range and the sensitivity of 0.14 nA mM(-1) at 0.4 V vs. Ag/AgCl. The sensors, as made, were stable for more than 3 days within a limited deterioration. PMID:15636507

Park, Sejin; Chung, Taek Dong; Kang, Sun Kil; Jeong, Ran-A; Boo, Hankil; Kim, Hee Chan

2004-12-01

374

Radioactive potential of zirconium-dioxide used for dental applications.  

PubMed

Purpose: The purpose of this study was to investigate the possible radioactive potential of zirconium dioxide (ZrO2) dental ceramics. Such information is necessary since they became an integral part of routine prosthetic rehabilitations and devoid of scientific information about their radioactivity creates some concern in the dental community. Methods: Four different types of commercial ZrO2 ceramics, namely Lava, Cercon, ICE Zirkon, and Everest Bio ZS were investigated before and after the sintering process. Sintering temperatures were applied according to each manufacturer's instructions. The compositions of the presintered and sintered specimens were analyzed using x-Ray Fluorescence Spectrometer (XRF). Concentrations of the elements and compounds were also measured by this method. Determination of radioactivity continued with Gamma-spectrometry measurements and Gross alpha/Beta analyses. Results: The activity of gamma and Gross alpha/beta was below minimum detection limits (MDL) for presintered and sintered ZrO2. The MDLs of gross alpha/beta counting system were 0.02 Bq/g and 0.01 Bq/g for alpha and beta radioactivity, respectively. The sintering process played only a minor role in the composition of the compounds. Conclusions: Radioactivity of the ZrO2 ceramics studied showed negligible radionuclide activity that can be considered lower than many hazardous radioactive appliances in our environment. PMID:22865573

Bavbek, Andac Barkin; Ozcan, Mutlu; Eskitascioglu, Gürcan

2014-01-01

375

Anisotropy of point defect diffusion in alpha-zirconium  

NASA Astrophysics Data System (ADS)

Two types of intrinsic defect, i.e., vacancy and self-interstitial atom (SIA), are formed in metals during irradiation with energetic particles. The evolution of defect population leads to significant changes in microstructure and causes a number of radiation-induced property changes. Some phenomena, such as radiation growth of anisotropic materials, are due to anisotropy in the atomic mass transport by point defects. Detailed information on atomic-scale mechanisms is, therefore, necessary to understand such phenomena. In this article, we present results of a computer simulation study of mass transport via point defects in alpha-zirconium. The matrix of self-diffusion coefficients and activation energies for vacancy and SIA defects have been obtained, and different methods of treatment of diffusion have been tested. Molecular dynamics (MD) shows that vacancy diffusion is approximately isotropic in the temperature range studied (1050 to 1650 K), although some preference for basalplane diffusion was observed at the lower end of the range. The mechanism of interstitial diffusion changes from one-dimensional (1-D) in a <11bar 20> direction at low temperature (<300 K) to two-dimensional (2-D) in the basal plane and, then, three-dimensional (3-D) at higher temperatures.

Osetsky, Y. N.; Bacon, D. J.; de Diego, N.

2002-03-01

376

Gadolinium-hydrogen ion exchange of zirconium phosphate  

NASA Technical Reports Server (NTRS)

The Gd(+3)/H(+) ion exchange on a commercial zirconium phosphate ion exchanger was investigated in chloride, sulfate, and phosphate solutions of Gd(+3) at gadolinium concentrations of 0.001 to 1 millimole per cc and in the pH range of 0 to 3.5. Relatively low Gd(+3) capacities, in the range of 0.01 to 0.1 millimole per g of ion exchanger were found at room temperature. A significant difference in Gd(+3) sorption was observed, depending on whether the ion exchanger was converted from initial conditions of greater or lesser Gd(+3) sorption than the specific final conditions. Correlations were found between decrease in Gd(+3) capacity and loss of exchanger phosphate groups due to hydrolysis during washing and between increase in capacity and treatment with H3PO4. Fitting of the experimental data to ideal ion exchange equilibrium expressions indicated that each Gd(+3) ion is sorbed on only one site of the ion exchanger. The selectivity quotient was determined to be 2.5 + or - 0.4 at room temperature on gadolinium desorption in chloride solutions.

Liu, D. C.; Power, J. L.

1972-01-01

377

High temperature oxidation of some zirconium alloys in flowing oxygen  

NASA Astrophysics Data System (ADS)

The oxidation behavior of three zirconium alloys, Zr-2.2wt%Hf, Zr-2.5wt%Nb and Zr-3wt%Nb-1wt%Sn, has been studied in flowing oxygen in the temperature range 873-1173 K to 120 ks (2000 min). Zr-2.5Nb and Zr-3Nb-1Sn showed a transition to rapid linear kinetics after initial parabolic oxidation at all temperatures. Zr-2.2Hf, on the other hand, showed this transition at temperatures in the range 973-1173 K; no transition was observed at 873 K within the oxidation times reported. Zr-2.2Hf showed the smallest weight gains, followed by Zr-2.5Nb and Zr-3Nb-1Sn. Increased oxidation rates and shorter time-to-rate transition of Zr-2.5Nb and Zr-3Nb-1Sn as compared with Zr-2.2Hf are attributed to the presence of the alloying elements Nb, Sn and Hf. Based on the Nomura-Akutsu model, Hf should delay the rate transition, while Nb and Sn lead to shorter transition times. The scale on Zr-2.2Hf was identified as monoclinic zirconia, while the tetragonal phase, 6ZrO 2 · Nb 2O 5, was contained in the monoclinic zirconia scales on both other alloys.

Kohli, Rajiv

1980-06-01

378

Microstructure and mechanical properties of proton irradiated zirconium carbide  

NASA Astrophysics Data System (ADS)

Zirconium carbide is a candidate ceramic being considered for metal-carbide-base composite-type fuels, as well as for an alternative coating material for TRISO particle fuels. Ensuring adequate mechanical properties and dimensional stability in response to radiation is a key part in developing a practical ZrC-base fuel. The existing available radiation response data for ZrC is limited and insufficient. In the present study, ZrC was irradiated with a 2.6 MeV proton beam at 800 °C to doses of 0.7 and 1.5 dpa. Following radiation, the radiation induced damage microstructure is comprised of a high density of nanometer-sized Frank loops, but no irradiation induced amorphization, voids, or precipitates were observed. A slight lattice expansion was found in the irradiated ZrC, in good agreement with the reported results from neutron irradiation. The changes in microhardness and fracture toughness properties induced in the irradiated samples were measured using indentation techniques. The hardness and the fracture toughness both increase with increasing radiation dose.

Yang, Yong; Dickerson, Clayton A.; Swoboda, Hannah; Miller, Brandon; Allen, Todd R.

2008-09-01

379

Dynamic restoration mechanisms in {alpha}-zirconium at elevated temperatures  

SciTech Connect

The creep behavior of {alpha}-zirconium at high temperatures is not understood. Recently, steady-state stress exponents between 5 and 7 have been suggested over a range of elevated temperatures, indicating the predominance of dislocation climb (dynamic recovery) as the restoration mechanism. However, the activation energies are significantly higher than those of self-diffusion of pure Zr, as expected from climb-controlled mechanisms. This discrepancy and the observations of increased high-angle grain boundary area with straining have been attributed to the possible occurrence of discontinuous recrystallization and/or grain growth as additional restoration mechanisms. Tension, torsion and creep tests to small and large strains were performed at temperatures from 400 to 800 deg C. The microstructure of the deformed samples was characterized by optical microscopy, transmission electron microscopy, as well as texture analysis using X-ray and electron backscatter diffraction. Dynamic recovery through dislocation climb appears to be the prevailing restoration mechanism. The increase in high angle boundary area with larger strains is a consequence of geometric dynamic recrystallization.

Perez-Prado, M.T. [Department of Physical Metallurgy, CENIM-CSIC, Avda. de Gregorio del Amo, 8, 28040 Madrid (Spain)]. E-mail: tpprado@cenim.csic.es; Barrabes, S.R. [Department of Aerospace and Mechanical Engineering, University of Southern California, Olin Hall 430, Los Angeles, CA 90089 (United States); Kassner, M.E. [Department of Aerospace and Mechanical Engineering, University of Southern California, Olin Hall 430, Los Angeles, CA 90089 (United States); Evangelista, E. [Department of Mechanics, Polytechnic University of Marche, Ancona 60131 (Italy)

2005-02-01

380

Revisiting Zirconium: New Abundance Determinations with Improved Oscillator Strengths  

NASA Astrophysics Data System (ADS)

The element Zirconium is produced via neutron capture (n-capture). It resides in the mass range where there is uncertainty about the production mechanism at early time. The rapid n-capture process (r-process) was believed to be responsible for the production, but no study (Burris et al 2000, Gilroy et al 1988 and others) has been able to successfully use the r-process to reproduce the abundance signature for elements in this mass range for metal-poor halo stars. It has been suggested (Sneden and Cowan 2003) that there may be an undiscovered component to the r-process. New transition probabilities for Zr II have been reported by Malcheva et al (2006). We utilize these values to make new abundance determinations for Zr in the Sun and the metal-poor halo star BD +17 3248. This work is supported in part by the AAS Small Grant Program, the Arkansas Space Grant Consortium and the UCA Undergraduate Research Council.

Burris, Debra L.; Jones, M.; Nichols, R.

2006-12-01

381

Electrospun poly (vinyl alcohol)/ alpha-zirconium phosphate nanocomposite fibers  

NASA Astrophysics Data System (ADS)

Poly (vinyl alcohol) (PVA)/alpha-zirconium phosphate (ZrP) polymer nanocomposite (PNC) fibers were successfully prepared via the simple and low-cost electrospinning process. ZrP nanoparticles with two different dimensions, i.e., ZrP-500 with a lateral dimension of ca. 320 nm and an aspect ratio of ca. 500, and ZrP-1500 with a lateral dimension of ca. 950 nm and an aspect ratio of ca. 1500, were utilized to illustrate the size effect on the electrospun nanofibers. In order to obtain defect-free, uniform polymer nanocomposite fibers, a number of parameters including polymer concentration, feed rate, applied voltage and working distance between the needle tip and the fiber collecting substrate were investigated. Scanning electron microscopy (SEM) morphological analysis showed smooth and nonwoven electrospun nanofiber mat. Strong intermolecular interactions between the PVA matrix and the included ZrP nanofillers were revealed by the attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). The incorporation of ZrP nanofillers drastically improved the thermal stability of the PNC fibers. TGA results demonstrated a clear thermal stability dependence on the aspect ratio of the crystalline ZrP nanofillers. The degradation temperature was increased by 90 °C for the ZrP-1500 and 60 °C for ZrP-500 when the loading level was increased from 1% to 5%. Furthermore, the viscoelastic properties of the PNC solutions were studied by rheometer.

Lizu, Monira

382

Structural and electrical properties of zirconium doped yttrium oxide nanostructures  

NASA Astrophysics Data System (ADS)

A synthetic process for the formation of ZrxY1-xOy nanostructures is demonstrated by the reaction of yttrium nitrate hexahydrate with zirconium propoxide. The reactions are carried out at temperature 60°C and pressure 0.1 MPa. The energy dispersive X-ray (EDX) spectroscopy measurements confirm formation of ZrxY1-xOy nanostructures and the presence of carbonate and hydroxide species which are removed after high temperature anneals. It was found that the oxygen pressure during synthesis plays a determinant role on the structural properties of the nanostructure. This effect is further studied by atomic force microscopy (AFM) measurements and scanning electron microscope (SEM), which showed the formation of an isotopically organized structure. X-ray diffraction (XRD) measurement reveals that these changes in the nanostructural efficiency are associated with structural and compositional changes among the substrate. The dielectric constant as measured by the capacitance-voltage (C-V) technique is estimated to be around 39.05. C-V measurements taken at 1 MHz show the maximum capacitance for the Zr0.05Y0.95Oy film. The leakage current densities were below 10-5 A/cm2 for the Zr0.05Y0.95Oy film.

Bahari, Ali; Ebrahimzadeh, Masoud; Gholipur, Reza

2014-04-01

383

Improved Yttrium and Zirconium Abundances in Metal-Poor Stars  

NASA Astrophysics Data System (ADS)

Abstract We present new abundances of the lighter n-capture elements, Yttrium (Z=39) and Zirconium (Z=40) in the very metal poor, r-process rich stars BD+17 3248 and HD 221170. Very accurate abundances were obtained by use of the new transition probabilities for Y II published by Biémont et al. 2011, and Zr II by Malcheva et al. 2006, and by expanding the number of transitions employed for each element. For example, in BD+17 3248, we find log ???????=-0.03 +/- 0.03 (?????=0.15, from 23 lines) for Y II. As for Zr II, log ??????? = 0.65 +/- 0.03 (????? = 0.1, from 13 lines). The resulting abundance ratio is log ??????? [Y/Zr] = -0.68 +/- 0.05. The results for HD 221170 are in accord with those of BD+17 3248. The quantity of lines used to form the abundance means has increased significantly since the original studies of these stars, resulting in more trustworthy abundances. These observed abundance ratios are in agreement with an r-process-only value predicted from stellar models, but is under-abundant compared to an empirical model derived from direct analyses of meteoritic material. This ambiguity should stimulate further nucleosynthetic analysis to explain this abundance ratio. We would like to extend our gratitude to NSF grant AST-0908978 and the University of Texas Astronomy Department Rex G. Baker, Jr. Endowment for their financial support in this project.

Violante, Renata; Biemont, E.; Cowan, J. J.; Sneden, C.

2012-01-01

384

Zirconium umbelliferonephosphate - A luminescent organic-inorganic hybrid nanomaterial  

NASA Astrophysics Data System (ADS)

Zirconium umbelliferonephosphate (ZrO(UFP)) is prepared by nucleation in the ionic liquid [MeBu 3N][NTf 2]. According to electron microscopy the resulting nanoparticles exhibit mean particle diameters of about 50 nm. The organic-inorganic hybrid material ZrO(UFP) shows blue emission upon UV-excitation. Luminescence originates from the organic dye and is highly intense due to the molar amount of luminescent centers per nanoparticle. The as-prepared material turns out to be non-crystalline. Therefore, its chemical composition is validated by infrared spectroscopy, thermogravimetry, energy-dispersive X-ray analysis and elemental analysis. The results (i.e., thermal decomposition, Zr:P ratio, C-/H-concentration) are in accordance to the composition of ZrO(UFP). Upon addition of acid phosphatase the luminescence intensity of ZrO(UFP) is significantly increased due to enzymatic hydrolysis accompanied by a release of non-bound umbelliferone. Both aspects - the increase in luminescence intensity as well as the release of umbelliferone - might be of future interest regarding biomedical application of ZrO(UFP) nanoparticles.

Roming, Marcus; Feldmann, Claus

2011-03-01

385

Underflight Calibration of SOHO CDS by SERTS-97  

NASA Astrophysics Data System (ADS)

Flights of the SERTS sounding rocket were made in 1997, 1999, and 2000 to provide updated radiometric and wavelength calibrations for several experiments on the SOHO mission. Just before or after each of these flights, end-to-end radiometric calibrations of the rocket payload were carried out using an EUV transfer standard light-source specially re-calibrated against the primary standard of BESSY I. These measurements established the absolute SERTS responsivity within a relative uncertainty of 17 % over its bandpass of 30 nm to 36 nm. During the flights, SERTS and SOHO CDS observed the same solar locations, as demonstrated by subsequent data co-registration with simultaneous SOHO EIT images, allowing the SERTS calibrations to be directly applied to both CDS and EIT. Following is a brief summary of the SERTS-97 radiometric calibration and the underflight cross-calibration that it provided for the CDS NIS channels at a time shortly before SOHO's temporary loss of pointing control.

Thomas, R. J.

386

Chemical Behaviour of Zirconium Oxychloride Octahydrate and Acetic Acid in Precursor Solution for Zirconia Film Formation on Glass  

Microsoft Academic Search

Precursor solutions for zirconia films on soda lime silica glass substrate were prepared from zirconium oxychloride octahydrate (ZOO) and acetic acid (HOAC) maintaining the mol ratios, [HOAC]\\/[ZOO] = 2, 4, 6, 8 and 10. A characteristic UV absorption band at ~280 nm in the ~120 h aged precursor solutions was identified for acetate group of the zirconium acetato complexed species.

Sunirmal Jana; K. Biswas

1997-01-01

387

Studies on the Effect of Sulphate Ion on Zirconium Extraction from Nitric Acid Solution by Tributyl Phosphate/Kerosene Oil.  

National Technical Information Service (NTIS)

In process for zirconium - Hafnium separation by TBP solvent extraction the presence of SO sub 4 ions have an adverse effect on the distribution coefficient of Zirconium in aqueous and organic phases. A study work has therefore been carried out to see the...

J. Akhtar, K. A. Shahid

1985-01-01

388

Plastic energy dissipation model for lifetime prediction of zirconium and zircaloy-4 fatigued at RT and 400 C  

Microsoft Academic Search

Zirconium and zircaloy-4 are generally used as fuel tubes in pressurized heavy water reactors because of their low neutron absorption cross-section, excellent corrosion resistance, good strength and ductility. Low cycle fatigue properties of zirconium and zircaloy-4 were investigated at RT and 400 C. The microscopic structure was determined using scanning electron microscopy and transmission electron microscopy techniques. On the basis

Xiao Lin; Gu Haicheng

1998-01-01

389

Corrosion Cracking of Zirconium Cladding Tubes. A Review. 2. Effect of External Factors, Structure, and Properties of the Alloys  

Microsoft Academic Search

Data on the effect of various external factors (applied loads, iodine concentration, temperature, irradiation), structure,\\u000a and properties (strength, state of the surface, residual stresses, and hydrogen charging) of zirconium alloys on the mechanisms\\u000a of and resistance to stress corrosion cracking (SCC) of zirconium cladding tubes primarily in iodine-bearing media are presented.

S. A. Nikulin; A. B. Rozhnov

2005-01-01

390

Biodistribution of Ru97-labeled DTPA, DMSA and transferrin. [Diagnostic potential  

Microsoft Academic Search

Ruthenium-97 is being produced at the Brookhaven Linac Isotope Producer (BLIP). The favorable physical properties of Ru-97 and chemical reactivity of ruthenium offer a potential for using this isotope to label compounds useful for delayed scanning. Diethylenetriamine pentaacetic acid (DTPA), 2,3-Dimercaptosuccinic acid (DMSA), and Transferrin (TF) were labeled with Ru-97-chloride. Ru-97-DTPA and In-111-DTPA, injected intravenously, showed similar organ distribution, kinetics,

P. Som; Z. H. Oster; R. G. Fairchild; H. L. Atkins; A. B. Brill; M. C. Gil; S. C. Srivastava; G. E. Meinken; A. G. Goldman; P. Richards

1980-01-01

391

29 CFR 37.97 - What are the required elements of a Conciliation Agreement?  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false What are the required elements of a Conciliation Agreement? 37.97 Section 37.97... Compliance Procedures § 37.97 What are the required elements of a Conciliation Agreement? A Conciliation Agreement...

2013-07-01

392

47 CFR 97.315 - Certification of external RF power amplifiers.  

Code of Federal Regulations, 2010 CFR

...2009-10-01 false Certification of external RF power amplifiers. 97.315 Section 97.315...Standards § 97.315 Certification of external RF power amplifiers. (a) Any external RF power amplifier (see § 2.815 of the...

2009-10-01

393

47 CFR 97.315 - Certification of external RF power amplifiers.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Certification of external RF power amplifiers. 97.315 Section 97.315...Standards § 97.315 Certification of external RF power amplifiers. (a) Any external RF power amplifier (see § 2.815 of the...

2010-10-01

394

46 CFR 97.37-5 - General alarm bell contact maker.  

Code of Federal Regulations, 2013 CFR

... 2013-10-01 false General alarm bell contact maker. 97.37-5 Section 97.37-5...Etc. § 97.37-5 General alarm bell contact maker. Each general alarm contact maker must be marked in accordance with...

2013-10-01

395

Nonclassical ?-hydrogen elimination of hydrosilazido zirconium compounds via direct hydrogen transfer.  

PubMed

Salt metathesis reactions of Cp(2)(NR(2))ZrX (X = Cl, I, OTf) and lithium hydrosilazides ultimately afford hydride products Cp(2)(NR(2))ZrH that suggest unusual ?-hydrogen elimination processes. A likely intermediate in one of these reactions, Cp(2)Zr[N(SiHMe(2))t-Bu][N(SiHMe(2))(2)], is isolated under controlled synthetic conditions. Addition of alkali metal salts to this zirconium hydrosilazide compound produces the corresponding zirconium hydride. However as conditions are varied, a number of other pathways are also accessible, including C-H/Si-H dehydrocoupling, ?-abstraction of a CH, and ?-abstraction of a SiH. Our observations suggest that the conversion of (hydrosilazido)zirconocene to zirconium hydride and silanimine does not follow the classical four-center mechanism for ?-elimination. PMID:22620714

Yan, KaKing; Ellern, Arkady; Sadow, Aaron D

2012-06-01

396

Determination of fluoride in water - A modified zirconium-alizarin method  

USGS Publications Warehouse

A convenient, rapid colorimetric procedure using the zirconium-alizarin indicator acidified with sulfuric acid for the determination of fluoride in water is described. Since this acid indicator is stable indefinitely, it is more useful than other zirconium-alizarin reagents previously reported. The use of sulfuric acid alone in acidifying the zirconium-alizarin reagent makes possible the maximum suppression of the interference of sulfate. Control of the pH of the samples eliminates errors due to the alkalinity of the samples. The fluoride content of waters containing less than 500 parts per million of sulfate and less than 1000 p.p.m. of chloride may be determined within a limit of 0.1 p.p.m. when a 100-ml. sample is used.

Lamar, W. L.

1945-01-01

397

Solid-phase zirconium and fluoride species in alkaline zircaloy cladding waste at Hanford.  

PubMed

The United States Department of Energy Hanford Site, near Richland, Washington, USA, processed plutonium between 1944 and 1987. Fifty-six million gallons of waste of various origins remain, including waste from removing zircaloy fuel cladding using the so-called Zirflex process. The speciation of zirconium and fluoride in this waste is important because of the corrosivity and reactivity of fluoride as well as the (potentially) high density of Zr-phases. This study evaluates the solid-phase speciation of zirconium and fluoride using X-ray diffraction (XRD) and scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS). Two waste samples were analyzed: one waste sample that is relatively pure zirconium cladding waste from tank 241-AW-105 and another that is a blend of zirconium cladding wastes and other high-level wastes from tank 241-C-104. Villiaumite (NaF) was found to be the dominant fluoride species in the cladding waste and natrophosphate (Na7F[PO4]2·19H2O) was the dominant species in the blended waste. Most zirconium was present as a sub-micron amorphous Na-Zr-O phase in the cladding waste and a Na-Al-Zr-O phase in the blended waste. Some zirconium was present in both tanks as either rounded or elongated crystalline needles of Na-bearing ZrO2 that are up to 200?m in length. These results provide waste process planners the speciation data needed to develop disposal processes for this waste. PMID:24976128

Reynolds, Jacob G; Huber, Heinz J; Cooke, Gary A; Pestovich, John A

2014-08-15

398

Synthesis and characterization of zirconium-doped mesoporous nano-crystalline TiO2  

Microsoft Academic Search

A series of zirconium-doped nano-titania (Zr\\/TiO2) with various amounts of Zr were prepared by sol-gel method using titanium(iv) isopropoxide and zirconium nitrate as precursors. Zr\\/TiO2 samples were characterized using X-ray diffraction (XRD), surface area-pore volume measurements, infrared (FTIR) spectroscopy, UV-vis-diffuse reflectance spectroscopy (UV-vis-DRS), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, thermogravimetric (TG) analysis, and transmission electron microscopy (TEM) techniques. XRD data

Kanattukara Vijayan Bineesh; Dong-Kyu Kim; Dae-Won Park

2010-01-01

399

Separation of 90Y from 90Sr using zirconium vanadate as the ion exchanger.  

PubMed

The sorption and desorption behaviour of several radionuclides, including 241Am, 152,154Eu, 233U, 137Cs, 90Sr and 90Y was studied under varying acidities using zirconium vanadate as ion exchanger. The sorption follows the order: Cs > Eu > Am >Y > U, while Sr was not taken up by the ion exchanger. A radiochemical separation scheme for the 90Y daughter from its 90Sr parent using zirconium vanadate ion exchanger has been developed. The exchanger was synthesized and characterized in our laboratory. PMID:15082037

Roy, K; Mohapatra, P K; Rawat, N; Pal, D K; Basu, S; Manchanda, V K

2004-05-01

400

Bonding of sapphire to sapphire by eutectic mixture of aluminum oxide and zirconium oxide  

NASA Technical Reports Server (NTRS)

Bonding of an element comprising sapphire, ruby or blue sapphire to another element of such material with a eutectic mixture of aluminum oxide and zirconium oxide is discussed. The bonding mixture may be applied in the form of a distilled water slurry or by electron beam vapor deposition. In one embodiment the eutectic is formed in situ by applying a layer of zirconium oxide and then heating the assembly to a temperature above the eutectic temperature and below the melting point of the material from which the elements are formed. The formation of a sapphire rubidium maser cell utilizing eutectic bonding is shown.

Deluca, J. J. (inventor)

1975-01-01

401

Bonding of sapphire to sapphire by eutectic mixture of aluminum oxide and zirconium oxide  

NASA Technical Reports Server (NTRS)

An element comprising sapphire, ruby or blue sapphire can be bonded to another element of such material with a eutectic mixture of aluminum oxide and zirconium oxide. The bonding mixture may be applied in the form of a distilled water slurry or by electron beam vapor deposition. In one embodiment the eutectic is formed in situ by applying a layer of zirconium oxide and then heating the assembly to a temperature above the eutectic temperature and below the melting point of the material from which the elements are formed. The formation of a sapphire rubidium maser cell utilizing eutectic bonding is shown.

Deluca, J. J. (inventor)

1979-01-01

402

Structural insights into the p97-Ufd1-Npl4 complex  

PubMed Central

p97/VCP (Cdc48 in yeast) is an essential and abundant member of the AAA+ family of ATPases and is involved in a number of diverse cellular pathways through interactions with different adaptor proteins. The two most characterized adaptors for p97 are p47 and the Ufd1 (ubiquitin fusion degradation 1)-Npl4 (nuclear protein localization 4) complex. p47 directs p97 to membrane fusion events and has been shown to be involved in protein degradation. The Ufd1-Npl4 complex directs p97 to an essential role in endoplasmic reticulum-associated degradation and an important role in mitotic spindle disassembly postmitosis. Here we describe the structural features of the Ufd1-Npl4 complex and its interaction with p97 with the aid of EM and other biophysical techniques. The Ufd1-Npl4 heterodimer has an elongated bilobed structure that is ?80 × 30 ? in dimension. One Ufd1-Npl4 heterodimer is shown to interact with one p97 hexamer to form the p97-Ufd1-Npl4 complex. The Ufd1-Npl4 heterodimer emanates from one region on the periphery of the N-D1 plane of the p97 hexamer. Intriguingly, the p97-p47 and the p97-Ufd1-Npl4 complexes are significantly different in stoichiometry, symmetry, and quaternary arrangement, reflecting their specific actions and their ability to interact with additional cofactors that cooperate with p97 in diverse cellular pathways.

Pye, Valerie E.; Beuron, Fabienne; Keetch, Catherine A.; McKeown, Ciaran; Robinson, Carol V.; Meyer, Hemmo H.; Zhang, Xiaodong; Freemont, Paul S.

2007-01-01

403

Mitotic phosphorylation of VCIP135 blocks p97ATPase-mediated Golgi membrane fusion  

SciTech Connect

Highlights: •VCIP135 is mitotically phosphorylated on Threonine-760 and Serine-767 by Cdc2. •Phosphorylated VCIP135 does not bind to p97ATPase. •The phosphorylation of VCIP135 inhibits p97ATPase-mediated Golgi membrane fusion. -- Abstract: In mammals, the Golgi apparatus is disassembled early mitosis and reassembled at the end of mitosis. For Golgi disassembly, membrane fusion needs to be blocked. Golgi biogenesis requires two distinct p97ATPase-mediated membrane fusion, the p97/p47 and p97/p37 pathways. We previously reported that p47 phosphorylation on Serine-140 and p37 phosphorylation on Serine-56 and Threonine-59 result in mitotic inhibition of the p97/p47 and the p97/p37 pathways, respectively [11,14]. In this study, we show another mechanism of mitotic inhibition of p97-mediated Golgi membrane fusion. We clarified that VCIP135, an essential factor in both p97 membrane fusion pathways, is phosphorylated on Threonine-760 and Serine-767 by Cdc2 at mitosis and that this phosphorylated VCIP135 does not bind to p97. An in vitro Golgi reassembly assay revealed that VCIP135(T760E, S767E), which mimics mitotic phosphorylation, caused no cisternal regrowth. Our results indicate that the phosphorylation of VCIP135 on Threonine-760 and Serine-767 inhibits p97-mediated Golgi membrane fusion at mitosis.

Totsukawa, Go; Matsuo, Ayaka; Kubota, Ayano; Taguchi, Yuya; Kondo, Hisao, E-mail: hk228@med.kyushu-u.ac.jp

2013-04-05

404

The initial, thermal oxidation of zirconium at room temperature  

SciTech Connect

Angle-resolved x-ray photoelectron spectroscopy (ARXPS) and in situ spectroscopic ellipsometry have been used to investigate the initial oxidation of polycrystalline zirconium at room temperature in the partial oxygen pressure range of 1.3x10{sup -7}-1.3x10{sup -4} Pa. Detailed quantitative analysis of the measured Zr 3d ARXPS spectra of the oxidized metal allowed separation of the intrinsic and extrinsic metallic and oxidic contributions to the spectra. It was shown that, in addition to the metallic contribution from the substrate and the oxidic contribution from stoichiometric ZrO{sub 2}, two additional suboxidic components are contained in the measured Zr 3d spectra of the oxidized Zr metal. As evidenced by angle-resolved XPS and in situ ellipsometry, both of these components can be attributed to a gradient of Zr enrichment in the region of the oxide film adjacent to the metal/oxide interface (with the highest Zr enrichment at the metal/oxide interface). Investigation of the oxide-film growth kinetics at various pO{sub 2}, as determined independently using both techniques, showed the occurrence of an initial regime of very fast, electric-field-controlled growth, followed by a much slower oxidation stage. As a result, an, on average, nonstoichiometric oxide film develops. The observed effect of the pO{sub 2} on the low-temperature oxidation of Zr has been discussed in terms of the relationship between the fraction of coverage of the surface with physi- and chemisorbed oxygen and the applied pO{sub 2}.

Lyapin, A.; Jeurgens, L.P.H.; Graat, P.C.J.; Mittemeijer, E.J. [Max Planck Institute for Metals Research, Heisenbergstrabe 3, D-70569 Stuttgart (Germany)

2004-12-15

405

Nuclear Magnetic Resonance Studies of Amorphous Nickel-Zirconium Hydrides.  

NASA Astrophysics Data System (ADS)

This research deals with one aspect of the scientific field of hydrogen in metals. The study of hydrogen in metals is technologically important for many reasons, among them is the use of hydrogen in metals to store energy. Hydrogen related energy technology is particularly attractive because hydrogen can be extracted from water, our most abundant resource, and can be used without any pollution. Metal hydrides may one day be widely used for automotive propulsion in cars, in batteries, and many other energy conversion devices. Amorphous NiZr is particularly interesting for hydrogen storage because high concentrations of hydrogen can be sorbed and desorbed repeatedly with only small deleterious effects to the metal. The motion of hydrogen and deuterium in amorphous nickel zirconium alloys (a-NiZr) has been studied and some properties of the local atomic structure in this amorphous metal have been deduced. This has been accomplished with nuclear magnetic resonance experiments measuring the spin lattice relaxation rate R_1 as a function of temperature and resonance frequency. Hydrogen can diffuse into and then through metals by hopping among interstitial positions. In a-NiZr the interstitial hydrogen positions are the centers of tetrahedra, with metal ions at the corners of the tetrahedra. Diffusive hydrogen motion occurs via classical over the barrier jumps, with a Gaussian distribution of activation energies for diffusion. The existence of a distribution of activation energies for diffusion is evidence supporting the densely packed random sphere model for the atomic structure of amorphous metals. The low temperature R_1 data is anomalous. Precipitation of Ni clusters out of the a-NiZr lattice may be occurring and causing unexpected spin lattice relaxation.

Hoke, Harris Clarence, Jr.

406

Zirconium Systematics in HT Metamorphic Rutile: Implications for Geothermometry  

NASA Astrophysics Data System (ADS)

The Zr-in rutile geothermometer is well-calibrated and widely used for temperature estimates of metamorphic rocks. Although the geothermometer has been successfully used to constrain peak temperatures for granulite facies rocks, experimental data suggest that Zr re-equilibration may occur following post-peak metamorphism. Some field-based studies reported a large range of Zr concentrations in rutile from granulites, possibly indicating such (partial) resetting. Further investigation into the Zr systematics of rutile is needed to enable better interpretation of Zr-in-rutile temperatures and their geologic significance. For this purpose, we investigated trace element contents of rutile grains from slowly cooled granulites. Rutile grains (120-280 ?m) in three zircon-bearing granulite-facies metapelites from the Pikwitonei Granulite Domain, Canada, were analyzed by electron probe micro-analyzer. The Zr contents were investigated by measuring compositional profiles and X-ray maps. To investigate diffusive effects, Nb, Cr, and V, which should exhibit higher diffusivities than Zr, were measured simultaneously with Zr. Concentrations of all elements show minor variation within grains, but differ up to a factor 4 between grains. Elemental zoning does not indicate diffusive re-equilibration, demonstrating that the Zr-in-rutile thermometer is robust to post-peak metamorphic resetting and the diffusivity is slower than suggested in experimental studies. Zirconium zoning in Zr-rich grains (3000-4600 ppm) suggests activity of ZrO2 <1 at peak conditions in spite of zircon presence. This indicates that for dry UHT rocks the highest Zr contents best approximate peak temperatures. For the studied Pikwitonei granulites, the highest Zr-in-rutile concentrations correspond to ca. 900 °C, which exceeds previous estimates using solvus equilibria (ca. 820 °C). This demonstrates the advantage of the robust Zr-in-rutile thermometer in constraining peak temperatures of high and ultrahigh-temperature rocks.

Kooijman, E.; Smit, M.; Mezger, K.; Berndt, J.

2011-12-01

407

Growth and characterization of nanocrystalline zirconium nitride-inconel structures  

NASA Astrophysics Data System (ADS)

This paper reports on the investigation of the physical, chemical, optical, mechanical, and tribological properties of reactively sputtered zirconium nitride-inconel composite nanocrystalline mixture films. These films were co-sputtered from a Zr and an inconel targets onto Si (111) substrates at room temperature using a fixed power to the Zr target (PZr) and a fixed flow of nitrogen and argon. Two sets of samples were produced by (1) varying the power to the inconel target (Pinc) and using a fixed bias voltage Vb and (2) by varying Vb and keeping Pinc fixed. The elemental composition was deduced from x-ray photoelectron spectroscopy, and was found to be influenced by Pinc and Vb. X-ray diffraction revealed the presence of nanocrystals of ZrN with a pattern typical of the NaCl structure. The grain size was found to decrease with the increase in ``inconel'' content in the film. The optical constants were measured using spectroscopic ellipsometry and were subsequently simulated using a Drude-Lorentz model. A correlation between film structure-composition and optical constants was established. The hardness and elastic modulus of each sample were measured by nanoindentation. The hardest films were produced using a Vb=-130 V bias voltage and Pinc=4 W. Microwear measurements were carried out using positive constant normal loads and the wear tracks were imaged and processed. The measured values for the friction coefficients, residual depth of tip indentations, wear volumes, and surface roughness were reported. The lowest recorded wear volume using a load of 4 mN was 10-3 ?m. Finally, the coatings were worn against ball-bearing steel using a ball-on-disk tribotester. Characterization of the wear tracks were performed by profilometry. A low wear coefficient of 1.7×10-7 mm3/s was obtained for a load of 5 N.

Aouadi, S. M.; Maeruf, T.; Sodergren, M.; Mihut, D. M.; Rohde, S. L.; Xu, J.; Mishra, S. R.

2005-07-01

408

His75-Asp97 cluster in green proteorhodopsin.  

PubMed

The proteorhodopsin (PR) family found in bacteria near the ocean's surface consists of hundreds of PR variants color-tuned to their environment. PR contains a highly conserved single histidine at position 75, which is not found in most other retinal proteins. Using (13)C and (15)N MAS NMR, we were able to prove for green PR that His75 forms a pH-dependent H-bond with the primary proton acceptor Asp97, which explains its unusually high pK(a). The functional role of His75 has been studied using site-directed mutagenesis and time-resolved optical spectroscopy: Ultrafast vis-pump/vis-probe experiments on PR(H75N) showed that the primary reaction dynamics is retained, while flash photolysis experiments revealed an accelerated photocycle. Our data show the formation of a pH-dependent His-Asp cluster which might be typical for eubacterial retinal proteins. Despite its stabilizing function, His75 was found to slow the photocycle in wild-type PR. This means that PR was not optimized by evolution for fast proton transfer, which raises questions about its true function in vivo. PMID:21366243

Hempelmann, Franziska; Hölper, Soraya; Verhoefen, Mirka-Kristin; Woerner, Andreas C; Köhler, Thomas; Fiedler, Sarah-Anna; Pfleger, Nicole; Wachtveitl, Josef; Glaubitz, Clemens

2011-03-30

409

Dose effects in He implanted Eurofer97 steel  

NASA Astrophysics Data System (ADS)

Reduced Activation Ferritic/Martensitic steels are being extensively studied because of their foreseen application in fusion reactors. To reproduce neutron irradiation conditions, Eurofer97 samples were implanted at room temperature with helium ions at energies of 500 keV and 2 MeV and doses of 1×1015-1017 He /cm2. The implantation induced defects were characterized by positron beam Doppler Broadening (DB). The samples were annealed in the range 300 – 1500 K, in 100 K steps. As the temperature increases, the annealing of vacancies and vacancy clusters is noticed and followed by the coalescence of HenVm clusters. At temperatures around 1200 K HeV pairs dissociate and bubbles are formed. Above 1300 K the helium release from bubbles is observed. The S-W graphs reveals that the samples have similar positron traps up to 1200 K. At 1200 K helium bubbles are noticed and the S, W pair shows a clearly distinct behaviour from the S, W values of vacancy type defects. As the temperature increases and helium is release, the S, W pairs shift towards the S, W's of vacancies.

Carvalho, I.; Schut, H.; Fedorov, A.; Luzginova, N.; Desgardin, P.; Sietsma, J.

2014-04-01

410

Microstructural characterization of EUROFER 97 during low-cycle fatigue  

NASA Astrophysics Data System (ADS)

The quenched and tempered reduced-activation ferritic/martensitic steel EUROFER 97 is one of the candidates for structural components of Generation IV nuclear power plants. The cyclic behaviour of this steel during isothermal plastic strain-controlled tests was investigated at room temperature and at 550 °C. Under low-cycle fatigue test this steel shows, after the first few cycles, a pronounced cyclic softening accompanied by microstructural changes such as the decrease of the free dislocation density inside the subgrain. The rate of softening increases with temperature being very pronounced at temperatures above 500 °C. The evolution of the flow stress during cycling was studied by analyzing the so-called "back" and "friction" stresses obtained from the hysteresis loops measured along the entire test. From the analysis of the hysteresis loops and corroborated by electron microscopy observations, it can be concluded that the strong cyclic softening observed is produced by the decrease exhibited by the friction stress. The Taylor coefficient was calculated measuring the evolution of the free dislocation density.

Giordana, M. F.; Alvarez-Armas, I.; Armas, A.

2012-05-01

411

Endocrine function in 97 patients with myotonic dystrophy type 1.  

PubMed

The aim of this study was to investigate the endocrine function and its association to number of CTG repeats in patients with myotonic dystrophy type 1 (DM1). Concentration of various hormones and metabolites in venous blood was used to assess the endocrine function in 97 patients with DM1. Correlation with CTG(n) expansion size was investigated with the Pearson correlation test. Eighteen percent of the DM1 patients had hyperparathyroidism with increased PTH compared with 0.5% in the background population. Of these, 16% had normocalcemia and 2% had hypercalcemia. An additional 3% had hypercalcemia without elevation of PTH; 7% had abnormal TSH values (2% subnormal and 5% elevated TSH levels); 5% of the patients had type 2 diabetes mellitus; 17% of the male DM1 patients had increased LH and low levels of plasma testosterone indicating absolute androgen insufficiency. Another 21% had increased LH, but normal testosterone levels, indicating relative insufficiency. Numbers of CTG repeats correlated directly with plasma PTH, phosphate, LH, and tended to correlate with plasma testosterone for males. This is the largest study of endocrine dysfunction in a cohort of Caucasian patients with DM1. We found that patients with DM1 have an increased risk of abnormal endocrine function, particularly calcium metabolism disorders. However, the endocrine dysfunction appears not to be of clinical significance in all of the cases. Finally, we found correlations between CTG(n) expansion size and plasma PTH, phosphate, and testosterone, and neck flexion strength. PMID:22349862

Ørngreen, M C; Arlien-Søborg, P; Duno, M; Hertz, J M; Vissing, J

2012-05-01

412

Embrittlement of RAFM EUROFER97 by implanted hydrogen  

NASA Astrophysics Data System (ADS)

About 380 ?m thick specimens of low-activation martensitic stainless steel EUROFER97 were homogeneously implanted with protons below about 70 °C to concentrations up to about 1200 appm. Tensile tests were performed at 25 and 200 °C. The tests at 25 °C showed an increase of yield stress and ultimate tensile strength and a decrease of uniform elongation and elongation to fracture, while effects at 200 °C were strongly reduced. Scanning electron microscopy showed virtually no change of the ductile, transgranular fracture mode by the implanted H. A slight decrease of necking was observed only at the highest concentrations. The results are compared to previous measurements on F82H-mod and to literature results on tensile tests after He implantation and neutron irradiation. F82H-mod specimens were also implanted under applied tensile stress to concentrations up to 1900 appm. Straining was ascribed to accumulation of atomic defects, but no fracturing occurred. Thermal desorption measurements are included on H-implanted and tensile tested F82H-mod specimens. The results show significant data scatter, even within one specimen, with the highest measured values being in accordance with the implanted amount. In general, the H content is decreased after testing at higher temperatures, but even after testing at 350 °C, some specimens contain significant amounts.

Liu, C.; Klein, H.; Jung, P.

2004-10-01

413

Preparation and characterization of zirconium containing mesoporous silicas. II. Grafting reaction of tetraneopentyl zirconium on MCM-41 and characterization of the grafted species and of the resulting materials  

Microsoft Academic Search

Hydroxyl groups of MCM-41 dehydroxylated under vacuum at 500 °C react with tetraneopentyl zirconium, leading to the evolution of neopentane and the formation of organometallic species with the mean formula (?Si?O)2ZrNp2 which were fully characterized by physicochemical methods such as solid-state NMR, infrared spectroscopy, quantification of evolved gases and microanalysis. Decomposition of the resulting materials under vacuum, oxygen, water and

Xu-Xu Wang; Laurent Veyre; Frédéric Lefebvre; Joël Patarin; Jean-Marie Basset

2003-01-01

414

34 CFR 97.110 - Expedited review procedures for certain kinds of research involving no more than minimal risk...  

Code of Federal Regulations, 2011 CFR

...review procedures for certain kinds of research involving no more than minimal risk, and for minor changes in approved research. 97.110 Section 97.110...ED Policy for Protection of Human Research Subjects) § 97.110...

2011-07-01

415

34 CFR 97.110 - Expedited review procedures for certain kinds of research involving no more than minimal risk...  

Code of Federal Regulations, 2010 CFR

...review procedures for certain kinds of research involving no more than minimal risk, and for minor changes in approved research. 97.110 Section 97.110...ED Policy for Protection of Human Research Subjects) § 97.110...

2010-07-01

416

34 CFR 97.110 - Expedited review procedures for certain kinds of research involving no more than minimal risk...  

Code of Federal Regulations, 2013 CFR

...review procedures for certain kinds of research involving no more than minimal risk, and for minor changes in approved research. 97.110 Section 97.110...ED Policy for Protection of Human Research Subjects) § 97.110...

2013-07-01

417

34 CFR 97.110 - Expedited review procedures for certain kinds of research involving no more than minimal risk...  

Code of Federal Regulations, 2012 CFR

...review procedures for certain kinds of research involving no more than minimal risk, and for minor changes in approved research. 97.110 Section 97.110...ED Policy for Protection of Human Research Subjects) § 97.110...

2012-07-01

418

Influence of dislocation-solute interactions on the mechanical properties of zirconium-doped NiAl  

SciTech Connect

Atom probe field ion microscopy (APFIM) has been used to characterize NiAl microalloyed with molybdenum and zirconium. Field ion images and atom probe analyses revealed segregation of zirconium to dislocation strain fields and ribbon-like morphological features that are probably related to dislocations. These results provide direct experimental evidence in support of the suggestion that the tremendous increase in the ductile-to-brittle transition temperature (DBTI) in zirconium-doped NiAl is due to pinning of dislocations by zirconium atoms. Atom probe analyses also revealed segregation of zirconium to grain boundaries. This result is consistent with the change from an intergranular fracture mode in undoped NiAl to a mixture of intergranular and transgranular fracture mode in zirconium-doped NiAl. The NiAl matrix was severely depleted of the solutes molybdenum and zirconium. Small Mo-rich precipitates, detected in the matrix and grain boundaries, are likely to contribute to the significant increase in the room-temperature yield stress of microalloyed NiAl through a precipitation hardening mechanism.

Jayaram, R. [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Materials Science and Engineering; Miller, M.K. [Oak Ridge National Lab., TN (United States)

1995-03-01

419

Ship-in-bottle synthesis of the mixed-layered compounds of clay silicate/zirconium phosphate.  

PubMed

An attempt was made to synthesize artificial mixed-layered compounds between montmorillonite silicate and ?-zirconium phosphate using a ship-in-bottle approach. The interlayer cations of montmorillonite were first exchanged with hydroxy-zirconium oligomeric cations, which were then subjected to a reaction with phosphoric acid or phenylphosphoric acid to develop ?-zirconium phosphate layers (Zr(R-OPO3)2; R = H, C6H5) between the clay silicate layers. The attempt of the reaction with phosphoric acid failed; hydroxy-zirconium cations were removed out of the interlayer space, forming ?-zirconium phosphate outside of montmorillonite. The phenylphosphate derivative, montmorillonite/Zr(C6H5OPO3)2, with a regular mixed-layered structure has been successfully obtained, showing a basal spacing corresponding to the sum of the thicknesses of the individual layers. When a polyvinyl alcohol (PVA) aqueous solution was used in the preparation of the hydroxy-zirconium exchanged montmorillonite, PVA was incorporated with hydroxy-zirconium complex cations between the silicate layers. The resulting compound can adsorb phosphate ions. Although this is not a mixed-layered compound in the context of this study, the selective and reversible phosphate ion exchange properties are worth noting for future study. PMID:24849848

Kawagoe, Hiroshi; Imo-Oka, Naoya; Shinohara, Hiroyasu; Yamanaka, Shoji

2014-07-21

420

The Invasion and Metastasis Promotion Role of CD97 Small Isoform in Gastric Carcinoma  

PubMed Central

CD97 is over-expressed in the majority of gastric adenocarcinomas and is associated with its dedifferentiation and aggressiveness. Our previous results demonstrated that out of three CD97 isoforms tested, only the small one was able to promote increased invasiveness in vitro. Based on these data we further aimed to investigate the role of CD97 small isoform in gastric cancer progression in vivo by employing the cells with a stable CD97 small isoform knock-down and an orthotopic gastric cancer mouse model. We could demonstrate that the knock down of CD97/EGF1,2,5, led to a significant decrease in the number of cells penetrating the gelatin coated membrane as compared with control cells. In the gastric cancer mouse model, both the hypodermic and the orthotopic yielded tumor masses of the CD97/EGF1,2,5kd group and were significantly smaller than the control. Metastatic tumor cell number in early metastatic regional lymph nodes on post-operative day 42 was distinctly decreased in the CD97/EGF1,2,5kd group as compared with the SGC-NS group, and was accompanied with the downregulation of CD44, VEGFR, CD31 and CD97. We concluded in this study that CD97 small isoform not only supported gastric cancer local growth, but also promoted metastatic spread in orthotopically implanted mouse model suggesting involvement of the CD97 small isoform in the preparation of (pre)metastatic niche.

Liu, Daren; Trojanowicz, Bogusz; Ye, Longyun; Li, Chao; Zhang, Luqing; Li, Xiaowen; Li, Guogang; Zheng, Yixiong; Chen, Li

2012-01-01

421

Human Cytomegalovirus Protein Kinase UL97 Forms a Complex with the Tegument Phosphoprotein pp65?  

PubMed Central

UL97 is a protein kinase encoded by human cytomegalovirus (HCMV) and is an important target for antiviral drugs against this ubiquitous herpesvirus, which is a major cause of life-threatening opportunistic infections in the immunocompromised host. In an effort to better understand the function(s) of UL97 during HCMV replication, a recombinant HCMV, NTAP97, which expresses a tandem affinity purification (TAP) tag at the amino terminus of UL97, was used to obtain UL97 protein complexes from infected cells. pp65 (also known as UL83), the 65-kDa virion tegument phosphoprotein, specifically copurified with UL97 during TAP, as shown by mass spectrometry and Western blot analyses. Reciprocal coimmunoprecipitation experiments using lysates of infected cells also indicated an interaction between UL97 and pp65. Moreover, in a glutathione S-transferase (GST) pull-down experiment, purified GST-pp65 fusion protein specifically bound in vitro-translated UL97, suggesting that UL97 and pp65 do not require other viral proteins to form a complex and may directly interact. Notably, pp65 has been previously reported to form unusual aggregates during viral replication when UL97 is pharmacologically inhibited or genetically ablated, and a pp65 deletion mutant was observed to exhibit modest resistance to a UL97 inhibitor (M. N. Prichard, W. J. Britt, S. L. Daily, C. B. Hartline, and E. R. Kern, J. Virol. 79:15494-15502, 2005). A stable protein-protein interaction between pp65 and UL97 may be relevant to incorporation of these proteins into HCMV particles during virion morphogenesis, with potential implications for immunomodulation by HCMV, and may also be a mechanism by which UL97 is negatively regulated during HCMV replication.

Kamil, Jeremy P.; Coen, Donald M.

2007-01-01

422

Critical conditions for self-ignition of magnesium and zirconium powders  

Microsoft Academic Search

The ignition of metal powders in a gaseous oxidizing medium, the specimens being magnesium and zirconium powders, are studied. The difficulties of precise mathematical analysis of nonsteady-state heat and mass exchange processes in a porous system up to the point of ignition are addressed. The kinetic laws of oxidation were obtained by the thermogravimetric method. The values of the effective

N. E. Karpova; E. P. Goncharov; O. A. Kochetov

1986-01-01

423

ZIRCONIUM HAZARDS RESEARCH. Summary Report No. 3655 for September 1, 1956 to August 31, 1957  

Microsoft Academic Search

The sensitivity characteristics of a variety of Zr samples such as ; sponge, scrap, powder and process materials were studicd. Of particular interest ; was the determination of the relative seasitivity of these materials to such ; stimuli as impact, friction, electrostatic discharge, and heat. A study of the ; zirconium--water reaction at relatively low temperature was initiated. In ;

J. A. Herickes; P. A. Richardson; M. Weiss; G. Gelernter

1957-01-01

424

Recycle of Zirconium from Used Nuclear Fuel Cladding: A Major Element of Waste Reduction  

SciTech Connect

Feasibility tests were initiated to determine if the zirconium in commercial used nuclear fuel (UNF) cladding can be recovered in sufficient purity to permit re-use, and if the recovery process can be operated economically. Initial tests are being performed with unirradiated, non-radioactive samples of various types of Zircaloy materials that are used in UNF cladding to develop the recovery process and determine the degree of purification that can be obtained. Early results indicate that quantitative recovery can be accomplished and product contamination with alloy constituents can be controlled sufficiently to meet purification requirements. Future tests with actual radioactive UNF cladding are planned. The objective of current research is to determine the feasibility of recovery and recycle of zirconium from used fuel cladding wastes. Zircaloy cladding, which contains 98+% of hafnium-free zirconium, is the second largest mass, on average {approx}25 wt %, of the components in used U.S. light-water-reactor fuel assemblies. Therefore, recovery and recycle of the zirconium would enable a large reduction in geologic waste disposal for advanced fuel cycles. Current practice is to compact or grout the cladding waste and store it for subsequent disposal in a geologic repository. This paper describes results of initial tests being performed with unirradiated, non-radioactive samples of various types of Zircaloy materials that are used in UNF cladding to develop the recovery process and determine the degree of purification that can be obtained. Future tests with actual radioactive UNF cladding are planned.

Collins, Emory D [ORNL; DelCul, Guillermo D [ORNL; Terekhov, Dmitri [ORNL; Emmanuel, N. V. [Chemical Vapor Metal Refining, Inc.

2011-01-01

425

Fluorescence of europium(III) in a flouride glass containing zirconium  

NASA Astrophysics Data System (ADS)

Europium(III) incorporated in a new zirconium barium flouride glass shows 14 luminescent transitions (at 300 K) from 5D J ( J= 0,1,2,3) to 7F J ( J = 0,1,2,3,4) which are compared with Judd-Ofelt parameters for induced electric dipolar radiation, as well as for calculated magnetic dipolar transition probabilities.

Reisfeld, R.; Greenberg, E.; Brown, R. N.; Drexhage, M. G.; Jørgensen, C. K.

1983-02-01

426

Surface acidity and catalytic behavior of modified zirconium and titanium dioxides  

Microsoft Academic Search

Various modified zirconium and titanium dioxides were examined as catalysts for the following test reactions: the gas phase alkylation of 1-butene with isobutane, the double bond isomerization of 1-butene and the disproportionation of dichlorodifluoromethane. The catalysts were prepared by treatment of the precipitated oxide hydrates with either fluorinating, chlorinating, sulfatizing or phosphating agents.The nature of the acid sites was determined

A. Hess; E. Kemnitz

1997-01-01

427

Characterization of the Anelastic and Thermoelastic Properties of a Uranium--Nobium--Zirconium Alloy.  

National Technical Information Service (NTIS)

Anelastic and thermoelastic properties of the uranium-7.5 niobium--2.5 zirconium alloy have been measured by four types of tests: (1) effect of plastic strain on the shape of the stress-strain curves as a function of the permanent strain for two levels of...

T. D. Warner F. R. Winslow W. J. Hulsey A. M. Ammons J. W. Koger

1975-01-01

428

The concentrations of zirconium and hafnium in some igneous and metamorphic rocks and minerals  

Microsoft Academic Search

Zirconium and hafnium determinations on 47 rocks and minerals of widely different compositions and geographical occurrence indicate that the Zr \\/ Hf ratio of most crustal rocks is very close to 37. Lavas from Hawaii were found to have significantly higher ratios, as were some strongly differentiated rocks and certain minerals.

C. Kent Brooks

1970-01-01

429

21 CFR 700.16 - Use of aerosol cosmetic products containing zirconium.  

Code of Federal Regulations, 2010 CFR

...indicates that certain zirconium compounds have caused human skin granulomas and toxic effects in the lungs and other organs of experimental...lung is an organ, like skin, subject to the development of granulomas. Unlike the skin, the lung will not reveal the...

2009-04-01

430

21 CFR 700.16 - Use of aerosol cosmetic products containing zirconium.  

Code of Federal Regulations, 2010 CFR

...indicates that certain zirconium compounds have caused human skin granulomas and toxic effects in the lungs and other organs of experimental...lung is an organ, like skin, subject to the development of granulomas. Unlike the skin, the lung will not reveal the...

2010-04-01

431

Mechanical characterization of zirconium hydrides with high energy X-ray diffraction  

NASA Astrophysics Data System (ADS)

Zirconium and its alloys are of technical importance, finding application as a structural material in the nuclear industry. Engineering components fabricated from zirconium slowly pick-up hydrogen as a result of in-reactor corrosion, degrading the components mechanical properties as a brittle hydride phase forms. This dissertation applies high energy X-ray diffraction to directly measure the mechanical properties of zirconium hydrides in the bulk and at stress concentrations in zirconium alloys. The current study is presented as a manuscript format dissertation comprised of three manuscript chapters. Chapter 3 reports the in-situ loading of hydrided Zircaloy-2 and discusses hydride/Zircaloy-2 matrix interactions as a function of applied load. Chapter 4 reports the mechanical behavior at a fatigue pre-crack in un-hydrided Zircaloy-2, comparing the results to finite element and polycrystalline plasticity models of the crack tip. Chapter 5 reports the effect of hydrides on the notch tip strain field. The three manuscript chapters are followed by a general discussion in Chapter 6 and conclusions in Chapter 7.

Kerr, Matthew

432

Emulsions stabilized by precipitates of zirconium and tributyl phosphate degradation products  

Microsoft Academic Search

In the Purex process, a solvent extraction method of nuclear fuel reprocessing, a stable emulsion called crud forms at the interface between the oil and water phases. This paper reports that crud is an emulsion stabilized by finely dispersed solids. Insoluble residues and precipitates of zirconium and radiation-degraded products of tributyl phosphate (TBP) are key materials in crud formation. Cruds

H. Sugai; K. Munakata; S. Miyachi; S. Yasu

1992-01-01

433

Quantitative Neutronographic Analysis of Fibre Texture of Zirconium by the Time-of-Flight Method.  

National Technical Information Service (NTIS)

Quantitative neutronographic analysis of fibre texture of zirconium has been done by the time-of-flight method. On the IBR-30 pulsed reactor 16 diffraction spectra are measured on each of three deformation states of the sample. Pole figures have been dete...

M. Betzl K. Walther W. Matz K. Feldmann

1980-01-01

434

Nucleation and crystal growth of zirconium molybdate hydrate in nitric acid  

Microsoft Academic Search

Zirconium molybdate hydrate can precipitate in nitric acid media during the process of spent nuclear fuel recycling. The precipitates can occur either in the nitric acid dissolution solution or in the waste fission product solution, and can lead to the formation of fouling layers. If such layers are left to grow, they can generate dysfunctions requiring heavy mechanical intervention and

A. Magnaldo; M. Masson; R. Champion

2007-01-01

435

Formation and evolution of adiabatic shear bands in zirconium alloy impacted by split Hopkinson pressure bar  

NASA Astrophysics Data System (ADS)

The formation and evolution of the adiabatic shear bands in the zirconium alloy impacted by split Hopkinson pressure bar were investigated by means of the experimental design. The different strain levels in the zirconium alloy subjected to high strain rate loading were first designed by two times impact at almost same strain rate. Only deformed bands were formed in the zirconium alloy impacted once, and two types of adiabatic shear bands, namely deformed bands and transformed bands, were distinguished in the zirconium alloy impacted twice. Microstructural observation shows that the deformed bands showed the severe strain localization, and the transformed bands composed the ultrafine and equiaxed grains. The formation of the ultrafine and equiaxed grains in the transformed bands could be attributed to the rotational dynamic recrystallization mechanism. Based on the characterization of the ASBs formed at different strain stages, the evolution process of the ASBs is proposed. The deformed bands are suggested as the initial stage of the transformed bands formation, and the transformed bands are considered as the further development of the deformed bands. The microhardness measurements show that the microhardness values in the transformed bands were higher than that of the deformed bands and original sample because of strain hardening and grain refining.

Zou, D. L.; Luan, B. F.; Liu, Q.; Chai, L. J.; Chen, J. W.

2013-06-01

436

The electrochemistry of zirconium in aqueous solutions at elevated temperatures and pressures  

NASA Astrophysics Data System (ADS)

The electrochemistry of zirconium has been explored in borate buffer solution of pH = 6.94 at 250 °C with and without hydrogen by measuring the current, impedance, and capacitance as a function of potential. Data are interpreted in terms of modified point defect models (PDM) that recognize the existence of a thick oxide outer layer over a thin barrier layer. From thermodynamic analysis, it is postulated that a hydride barrier layer forms under PWR coolant conditions whereas an oxide barrier layer forms under BWR primary coolant conditions. Thus, the introduction of hydrogen into the solution lowers the corrosion potential of zirconium to the extent that the formation of ZrH 2 is predicted to be spontaneous rather than the ZrO 2. Mott-Schottky analysis shows that the passive film formed on zirconium is n-type, which is consistent with the PDM, corresponding to a preponderance of oxygen/hydrogen vacancies and/or zirconium interstitials in the barrier layer.

Chen, Yingzi; Urquidi-Macdonald, Mirna; Macdonald, Digby D.

2006-01-01

437

Development of zirconium/magnesium phosphate composites for immobilization of fission products  

SciTech Connect

Novel chemically bonded phosphate ceramics have been investigated for the capture and stabilization of volatile fission-product radionuclides. The authors have used low-temperature processing to fabricate zirconium phosphate and zirconium/magnesium phosphate composites. A zirconium/magnesium phosphate composite has been developed and shown to stabilize ash waste that has been contaminated with a radioactive surrogate of the {sup 137}Cs and {sup 90}Sr species. Excellent retention of cesium in the phosphate matrix system was observed in both short- and long-term leaching tests. The retention factor determined by the USEPA Toxicity Characteristic Leaching Procedure was one order of magnitude better for cesium that for strontium. The effective diffusivity, at room temperature, for cesium and strontium in the waste forms was estimated to be as low as 2.4 {times} 10{sup {minus}13} and 1.2 {times} 10{sup {minus}11} m{sup 2}/s, respectively. This behavior was attributed to the capture of cesium in the layered zirconium phosphate structure via an intercalation ion-exchange reaction, followed by microencapsulation. However, strontium is believed to be precipitated out in its phosphate form and subsequently microencapsulated in the phosphate ceramic. The performance of these final waste forms, as indicated by the compression strength and the durability in aqueous environments, satisfies the regulatory criteria.

Singh, D. Tlustochowicz, M.; Wagh, A.S. [Argonne National Lab., IL (United States). Energy Technology Div.

1999-01-01

438

Effect of self-interstitial diffusion anisotropy in electron-irradiated zirconium: A cluster dynamics modeling  

Microsoft Academic Search

A model based on the cluster dynamics approach was proposed in [A. Hardouin Duparc, C. Moingeon, N. Smetniansky-de-Grande, A. Barbu, J. Nucl. Mater. 302 (2002) 143] to describe point defect agglomeration in metals under irradiation. This model is restricted to materials where point defect diffusion is isotropic and is thus not applicable to anisotropic metals such as zirconium. Following the

F. Christien; A. Barbu

2005-01-01

439

The 5-year Results of an Oxidized Zirconium Femoral Component for TKA  

PubMed Central

Osteolysis secondary to polyethylene wear is one of the major factors limiting long-term performance of TKA. Oxidized zirconium is a new material that combines the strength of a metal with the wear properties of a ceramic. It remains unknown whether implants with a zirconium femoral component can be used safely in TKA. To answer that question, we reviewed, at a minimum of 5 years, the clinical outcome and survivorship of a ceramic-surfaced oxidized zirconium femoral component implanted during 98 primary TKAs between April 2001 and December 2003. Survivorship was 98.7% at 7 years postoperatively. No revision was necessary and only one component failed because of aseptic loosening. Mean Knee Society score improved from 36 to 89. No adverse events were observed clinically or radiologically. These results justify pursuing the use of oxidized zirconium as an alternative bearing surface for a femoral component in TKA. Level of Evidence: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Innocenti, Massimo; Carulli, Christian; Matassi, Fabrizio; Villano, Marco

2009-01-01

440

DETERMINATION OF ZIRCONIUM IN ROCKS AND QUARTZ SANDS RICH IN IRON  

Microsoft Academic Search

A method for the determination of small quantities of zirconium (some ; units per thousand) in rocks and quartziferous sands of high iron contents was ; developed. The major part of the iron is eliminated by distillation in a ; chlorine stream and in the presence of graphite at approximately 350 deg C. A ; second distillation at 650 deg

Borlera

1959-01-01

441

ADSORPTION AND RECOVERY OF NITRATED POLYCYCLIC AROMATIC HYDROCARBONS ON HYBRID SURFACTANT EXPANDED ZIRCONIUM-PHOSPHATE  

Microsoft Academic Search

This paper focuses on the removal of nitro substituted polycyclic aromatic hydrocarbon compounds (NPAHs) from water using low cost synthesized zirconium phosphate mesoporous materials. These materials are lamellar type incorporating n-alkyl-(n = 12 and n = 16) trimethylamonium bromide molecules with different concentrations. For comparison of their performance as adsorbents and in the recovery of NPAH, their results were compared

M. Algarra; M. V. Jiménez; F. G. Sánchez; J. Soto; J. J. Jiménez; Joaquim C. G. Esteves da Silva

2009-01-01

442

Zirconium tungstate hydroxide hydrate revisited: Crystallization dependence on halide and hydronium ions  

SciTech Connect

The formation of zirconium tungstate hydroxide hydrate, a precursor to the negative thermal expansion material cubic zirconium tungstate, shows a strong dependence on hydrothermal reaction conditions. It was found that not only the acid concentration, but also the acid counterion plays a significant role in the crystallization of ZrW{sub 2}O{sub 7}(OH){sub 2}.2H{sub 2}O. High temperatures, high acid concentrations, and the presence of chloride or bromide ions promote the formation of well-crystallized ZrW{sub 2}O{sub 7}(OH){sub 2}.2H{sub 2}O. For low acid concentrations, a new zirconium tungstate hydrate polymorph is observed, which transforms to tetragonal ZrW{sub 2}O{sub 7}(OH){sub 2}.2H{sub 2}O at longer reaction times. A study of crystallization kinetics in hydrochloric acid is presented. - Graphical abstract: The formation of ZrW{sub 2}O{sub 7}(OH){sub 2}.2H{sub 2}O shows a strong dependence on reaction conditions. Both acid concentration and acid counterion play a significant role in the crystallization. High temperatures, high acid concentrations, and the presence of chloride or bromide ions promote the formation of well-crystallized ZrW{sub 2}O{sub 7}(OH){sub 2}.2H{sub 2}O. For low acid concentrations, a new zirconium tungstate hydrate polymorph is observed.

Colin, Julie A. [Department of Chemistry, MS 602, University of Toledo, Toledo, OH 43606 (United States)], E-mail: julie.colin@utoledo.edu; Camper, DeMarco V.; Gates, Stacy D. [Department of Chemistry, MS 602, University of Toledo, Toledo, OH 43606 (United States); Simon, Monty D. [Department of Chemistry, MS 602, University of Toledo, Toledo, OH 43606 (United States)], E-mail: monty.simon@utoledo.edu; Witker, Karen L. [Department of Chemistry, MS 602, University of Toledo, Toledo, OH 43606 (United States)], E-mail: kwitker@muskingum.edu; Lind, Cora [Department of Chemistry, MS 602, University of Toledo, Toledo, OH 43606 (United States)], E-mail: cora.lind@utoledo.edu

2007-12-15

443

Determination of zirconium, barium, lanthanum, aluminium, sodium, hafnium and fluorine in fluorozirconate glasses  

Microsoft Academic Search

A procedure is described for the determination of the cationic and anionic components in fluorozirconate glasses. Zirconium, barium, aluminium, lanthanum, sodium and hafnium were determined by inductively coupled plasma atomic emission spectrometry (ICP\\/AES) after dissolution of the sample with an acid mixture in a microwave oven. The fluorine content was evaluated with two different techniques, namely potentiometry with a fluoride

O. Abollino; E. Mentasti; C. Sarzanini; E. Modone; M. Braglia

1992-01-01

444

Processing zirconium alloy used in light water reactors for specified creep rate  

Microsoft Academic Search

This patent describes a method for processing a zirconium alloy, material of a type wherein the material is subjected to a post extrusion meal, a series of an intermediate area reductions and intermediate recrystallization anneals possibly being a late stage beta, a final area reduction, and a final anneal. It comprises controlling creep rate in an alloy consisting essentially of

J. P. Foster; S. A. Worcester; R. J. Comstock

1992-01-01

445

Total Neutron Cross Section of Protons in the Zirconium Metal Lattice at Nitrogen Temperature.  

National Technical Information Service (NTIS)

The total neutron cross section of protons in the zirconium metal lattice can roughly be described by Fermi's well-known theory using a harmonic oscillator potential. It predicts cuspidal minima at the energy levels, reaching down to the value of the free...

P. Podewils

1980-01-01

446

Possibilities of surface coating for thermal insulation. [zirconium dioxide, titanium dioxide, and zircon coatings  

NASA Technical Reports Server (NTRS)

Calculations performed for pulsating heat sources indicate a relatively thin (200-1000 micron) coating can lower temperature both inside and on the surface of a construction material. Various coating materials (including zirconium dioxide) are discussed, together with possible thermic stresses and ways to deal with the latter.

Poeschel, E.; Weisser, G.

1979-01-01

447

Fast Fracture of a Zirconium Alloy Pressure Tube: Cause and Implications.  

National Technical Information Service (NTIS)

The cause of the unstable fracture of a Zircaloy-2 pressure tube in the core of a CANDU reactor is reviewed. Failure was associated with the presence of brittle zones of zirconium hydride which developed as a result of thermal gradient induced hydrogen di...

E. G. Price B. A. Cheadle

1985-01-01

448

AIE cation functionalized layered zirconium phosphate nanoplatelets: ion-exchange intercalation and cell imaging.  

PubMed

An aggregation-induced emission (AIE) probe, possessing a quaternary tetraphenylethene (TPEN) cation, was successfully intercalated into layered ?-zirconium phosphate (?-ZrP) nanosheets by ion-exchange. The hybrid materials emit strong blue emissions in aqueous solution which can be used as an effective fluorescence label for HeLa cells. PMID:24022258

Li, Dongdong; Miao, Chuanlong; Wang, Xiaodan; Yu, Xianghui; Yu, Jihong; Xu, Ruren

2013-10-25

449

Extraction of zirconium and hafnium from nitric acid solutions by solid extractant based on tributyl phosphate  

SciTech Connect

A study has been made of extraction equilibrium and kinetics and the influence of temperature and aqueous phase acidity on the extraction of zirconium and hafnium from nitric acid solutions by a solid extractant based on tributyl phosphate. Results are presented from pilot-plant experiments on Zr and Hf extraction from acidic pulps with high silicon contents, using pulsed columns.

Korovin, V.Yu.; Yagodin, G.A.; Savel`eva, V.I. [Dnieper Scientific Center, Dneprodzerzhinsk (Ukraine)

1994-10-20

450

Elastic Behavior of Arc-Cast Zirconium Carbide-Graphite Alloys.  

National Technical Information Service (NTIS)

The Young's modulus and shear modulus of arc-cast zirconium carbide-graphite alloys were measured as a function of graphite content and were found to be dependent upon the microstructure of these alloys. Attempts to fit several theoretical analyses to the...

R. C. Rossi R. D. Carnahan K. R. Janowski

1969-01-01

451

Extraction of zirconium(IV) from aqueous acid solutions by trioctylphosphine oxide  

SciTech Connect

The extraction of zirconium(IV) from aqueous solutions of hydrochloric, nitric and sulphuric acids by trioctylphosphine oxide (TOPO) in kerosene has been investigated under different conditions. The organic phases have been studied by infrared and nuclear magnetic resonance spectroscopies. The extraction equilibria are discussed in light of the results obtained. 7 figures, 2 tables.

Sato, T.

1983-01-01

452

Improving the thermal shock resistance of zirconium diboride ceramics  

NASA Astrophysics Data System (ADS)

Zirconium diboride (ZrB2) and ZrB2--SiC ceramics with densities greater than 99% were fabricated by hot pressing ZrB 2 and SiC powders and reactively hot pressing ZrH2, B 4C and Si to form ZrB2-27 vol% SiC. Thermophysical properties were investigated for hot pressed ZrB2 and ZrB2-30 vol% SiC ceramics. The thermal conductivity of ZrB2 increased from 56 W m-1 K-1 at room temperature to 67.0 W m -1 K-1 at 1675 K, whereas the thermal conductivity of ZrB2-SiC decreased from 62.0 W m-1 K-1 to 56 W m-1 K-1 over the same temperature range. Electron and phonon contributions to thermal conductivity were determined using electrical resistivity measurements and were used, along with grain size models, to explain the observed trends. Thermal shock of high density ZrB2, ZrB2--30 vol% SiC and ZrB2--30 vol% SiC/graphite - 15 vol% SiC fibrous monoliths was studied. Experimental thermal shock values measured during a water quench test were the same for both materials (DeltaT crit˜400°C). A finite element model was used to estimate the temperature gradients and stresses in both ceramics during quench testing. The model predicted that maximum thermal stresses exceeded the strength of ZrB2 (568 MPa) but not ZrB2-30 vol% SiC (863 MPa). The lower than predicted thermal shock resistance of ZrB2-SiC was attributed to the non-uniform cooling between the ZrB2 matrix and the SiC particulate phase. Water quench thermal shock testing of ZrB2-based fibrous monolith ceramics had a critical thermal shock temperature (Delta Tcrit) of 1400°C, a 250% improvement over the previously reported DeltaTcrit values of ZrB2 and ZrB2-30 vol.% SiC of similar dimensions (4 x 3 x 45 mm). The improvement in thermal shock resistance was attributed to cell boundary crack propagation and crack deflection around the load bearing cells.

Zimmermann, James William

453

Thermal equations of state of the {alpha}, {beta}, and {omega} phases of zirconium  

SciTech Connect

We have conducted synchrotron x-ray diffraction studies on high purity zirconium metal at pressures (P) up to 17 GPa and temperatures (T) up to 973 K. Unit cell volumes (V) were derived from the refinements of x-ray diffraction data for the {alpha}, {beta}, and {omega} phases of zirconium and fitted to a Birch-Murnaghan equation of state with the pressure derivative of the bulk modulus, K{sub 0}{sup '}, fixed at 4.0. The derived thermoelastic parameters for {alpha} zirconium are isothermal bulk modulus K{sub 0}=92(3) GPa, temperature derivative of bulk modulus ({partial_derivative}K/{partial_derivative}T){sub P}=-2.3(8)x10{sup -2} GPa/K, volumetric thermal expansivity {alpha}{sub T}=a+bT with a=1.5({+-}0.8)x10{sup -5} K{sup -1} and b=1.7({+-}1.4)x10{sup -8} K{sup -2}, and the pressure derivative of thermal expansion ({partial_derivative}{alpha}/{partial_derivative}P){sub T}=-2.7(9)x10{sup -6} GPa{sup -1} K{sup -1}. For the {beta} phase we obtained an isothermal bulk modulus of K{sub T}=66(3) GPa at 973 K and a unit-cell volume of V(973 K)=47.7(3) A{sup 3} at ambient pressure. For the {omega} zirconium we obtained K{sub 0}=90(5) GPa. Within the experimental errors, the K{sub 0} values we determined for the {alpha} and {omega} phases and volumetric thermal expansion for the {alpha} phase are in agreement with previous experimental results, whereas all other thermoelastic parameters represent the first determinations for the three crystalline phases of zirconium metal.

Zhao Yusheng; Zhang Jianzhong; Pantea, Cristian; Qian Jiang; Daemen, Luke L.; Rigg, Paulo A.; Hixson, Robert S.; Gray, George T. III; Yang Yunpeng; Wang Liping; Wang Yanbin; Uchida, Takeyuki [LANSCE Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); DX and MST Divisions, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Mineral Physics Institute, State University of New York, Stony Brook, New York 11794 (United States); GESCARS/APS, Argonne National Laboratory and University of Chicago, Illinois (United States)

2005-05-01

454

ISIS: Using an Explicit Model of Teamwork in RoboCup'97  

Microsoft Academic Search

Abstract Team ISIS (ISI Synthetic) successfully participated in the rst international RoboCup soccer tournament (RoboCup'97) held in Nagoya, Japan, in August 1997 ISIS won the third - place prize in over 30 teams that participated in the simulation league of RoboCup'97 (the most popular among the three RoboCup'97 leagues) In terms of re - search accomplishments, ISIS illustrated the usefulness

Ali Erdem; Gal A. Kaminka; Ion Muslea; Jafar Adibi; Marcello Tallis; Milind Tambe; Stacy C. Marsella; Yaser Al-onaizan

1998-01-01

455

SVIP Induces Localization of p97\\/VCP to the Plasma and Lysosomal Membranes and Regulates Autophagy  

Microsoft Academic Search

The small p97\\/VCP-interacting protein (SVIP) functions as an inhibitor of the endoplasmic reticulum (ER)-associated degradation (ERAD) pathway. Here we show that overexpression of SVIP in HeLa cells leads to localization of p97\\/VCP at the plasma membrane, intracellular foci and juxtanuclear vacuoles. The p97\\/VCP-positive vacuolar structures colocalized or associated with LC3 and lamp1, suggesting that SVIP may regulate autophagy. In support

Yang Wang; Petek Ballar; Yongwang Zhong; Xuebao Zhang; Chao Liu; Ying-Jiu Zhang; Mervyn J. Monteiro; Jun Li; Shengyun Fang

2011-01-01

456

The ubiquitin-selective chaperone CDC48\\/p97 links myosin assembly to human myopathy  

Microsoft Academic Search

Protein degradation in eukaryotes often requires the ubiquitin-selective chaperone p97 for substrate recruitment and ubiquitin-chain assembly. However, the physiological relevance of p97, and its role in developmental processes, remain unclear. Here, we discover an unanticipated function for CDC-48\\/p97 in myosin assembly and myofibril organization, both in Caenorhabditis elegans and humans. The developmentally regulated assembly of a CDC-48–UFD-2–CHN-1 complex links turnover

Philipp Christoph Janiesch; Johnny Kim; Julien Mouysset; Roja Barikbin; Hanns Lochmüller; Giuseppe Cassata; Sabine Krause; Thorsten Hoppe

2007-01-01

457

CASK regulates SAP97 conformation and its interactions with AMPA and NMDA receptors.  

PubMed

SAP97 interacts with AMPA receptors (AMPARs) and NMDA receptors (NMDARs) during sorting and trafficking to synapses. Here we addressed how SAP97 distinguishes between AMPARs and NMDARs and what role the adaptor/scaffold protein, CASK, plays in the process. Using intramolecular SAP97 Förster resonance energy transfer sensors, we demonstrated that SAP97 is in "extended" or "compact" conformations in vivo. SAP97 conformation was regulated by a direct interaction between SAP97 and CASK through L27 protein-interaction domains on each protein. Unbound SAP97 was mostly in the compact conformation, while CASK binding stabilized it in an extended conformation. In HEK cells and rat hippocampal neurons, SAP97 in the compact conformation preferentially associated and colocalized with GluA1-containing AMPARs, and in the extended conformation colocalized with GluN2B-containing NMDARs. Altogether, our findings suggest a molecular mechanism by which CASK binding regulates SAP97 conformation and its subsequent sorting and synaptic targeting of AMPARs and NMDARs during trafficking to synapses. PMID:23864692

Lin, Eric I; Jeyifous, Okunola; Green, William N

2013-07-17

458

Effect of the flame temperature on the characteristics of zirconium oxide fine particle synthesized by flame assisted spray pyrolysis  

NASA Astrophysics Data System (ADS)

Zirconium oxide fine particles were synthesized by flame assisted spray pyrolysis using zirconium chloride solution as precursor. Propane gas and air were used as a fuel and an oxidizer, respectively. The ratio of flow rate of oxidizer and fuel was maintained constant at 10:1 to ensure a complete combustion. Increasing fuel flow rate led to the increase of temperature distribution in the flame reactor. The intensity of XRD patterns increased with temperature and precursor concentration. Phase composition of zirconium oxide produced by this process consisted of monoclinic and tetragonal phases. The volume fraction of monoclinic phase of zirconium oxide increased with temperature and precursor concentration. The morphology particles observed by SEM resulted in spherical particles with size in the submicron range depending on the precursor concentration.

Widiyastuti, W.; Machmudah, Siti; Nurtono, Tantular; Winardi, Sugeng

2013-09-01

459

Methods of Analysis of Metal Refractories Borides, Carbides and Nitrides of Hafnium Niobium, Tantalum, Titanium and Zirconium.  

National Technical Information Service (NTIS)

The metallurgical program for which this laboratory provides analytical service has been primarily concerned with the borides, carbides, and nitrides of hafnium, niobium, tantalum, titanium, and zirconium. The recent production of purer and more complex m...

R. E. Dutton G. J. McKinley D. McLean H. F. Wendt

1965-01-01

460

Selective oxidation of butane to maleic anhydride on a vanadium-phosphorus oxide catalyst: Promotional effects of zirconium  

SciTech Connect

This study examines the role of zirconium as a promoter in the selective oxidation of n-butane to maleic anhydride on a vanadium-phosphorus oxide catalyst. Reaction studies show that low levels of zirconium (Zr/V = 0.03) decrease the temperature of maximum yield relative to the unpromoted catalyst. Higher levels of zirconium (Zr/V = 0.13) result in lower yields. [sup 16]O[sub 2]-[sup 18]O[sub 2] exchange measurements show no evidence for oxygen exchange between the gas phase and the bulk lattice at 400[degrees]C, in agreement with other studies. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) measurements are combined with the reaction studies to indicate a probable structural role for zirconium as a promoter. 19 refs., 9 figs., 3 tabs.

Sant, R.; Varma, A. (Univ. of Notre Dame, IN (United States))

1993-09-01

461

The effect of sulfur and zirconium co-doping on the oxidation of NiCrAl  

NASA Technical Reports Server (NTRS)

The adhesion behavior of Al2O3 scales formed on NiCrAl+Zr alloys was examined as a function of both sulfur and zirconium doping levels. In general, very high levels of zirconium were required to counteract the detrimental effects of sulfur. A sulfur-zirconium adherence map was constructed, as determined from the oxidation and spalling behavior in 1100 C cyclic tests. For low sulfur alloys (less than 500 ppma), the amount of zirconium required for adherence at any given sulfur level can be described by Zr greater than 600 S(0.2) (in ppma). These results underscore the importance of sulfur to adhesion mechanisms and suggest that sulfur gettering is a first order effect of reactive element additions to MCrAl alloys.

Smialek, James L.

1988-01-01

462

The effect of sulfur and zirconium Co-doping on the oxidation of NiCrAl  

NASA Technical Reports Server (NTRS)

The adhesion behavior of Al2O3 scales formed on NiCrAl+Zr alloys was examined as a function of both sulfur and zirconium doping levels. In general, very high levels of zirconium were required to counteract the detrimental effects of sulfur. A sulfur-zirconium adherence map was constructed, as determined from the oxidation and spalling behavior in 1100 C cyclic tests. For low sulfur alloys, the amount of zirconium required for adherence at any given sulfur level can be described by Zr greater than 600 S sup 0.2 (in ppma). These results underscore the importance of sulfur to adhesion mechanisms and suggests that sulfur gettering is a first order effect of reactive element additions to MCrAl alloys.

Smialek, James L.

1987-01-01

463

Low temperature growth mechanism of zirconium diboride films synthesised in flowing microwave Ar–BCl 3 post-discharges  

Microsoft Academic Search

Zirconium diboride films are synthesised at 460°C by a flowing microwave Ar–BCl3 post-discharge CVD process to coat Zircaloy-4 substrates. As a zirconium tetrachloride flow is of no use to synthesise these films, they are grown by a mechanism which consists of a diffusion step. To identify how this step occurs, characteristics of the films are compared with those that could

J. F. Pierson; T. Belmonte; H. Michel

1999-01-01

464

Role of photon emission for the increase of catalytic activity of SiO2 and zirconium polyphosphates  

Microsoft Academic Search

The influence of the monochromatic light with different wavelength on the catalytic activity and selectivity of SiO2 and zirconium polyphosphates was studied. It was shown that the wavelength of the falling irradiation differently influence on the rates of isopropyl alcohol dehydration and dehydrogenation on SiO2 surface. The influence of the falling irradiation on the catalytic activity and selectivity of zirconium

S. G. Gul'Yanova; O. K. Samuilova; T. K. Chechlova

1997-01-01

465

Effect of zirconium and molybdenum oxides on the surface and volume properties of an aluminocalcium oxide-fluoride melt  

NASA Astrophysics Data System (ADS)

The effect of additions of zirconium and molybdenum oxides on the surface tension and density of oxide-fluoride slags is studied by the method of the maximum pressure in a gas bubble. The obtained experimental and calculated results reveal a complex-forming character of the behavior of zirconium and molybdenum in oxide-fluoride slag melts, and they are used to estimate the sizes of the structural units present in the surface layer of the slags.

Agafonov, S. N.; Krasikov, S. A.

2013-02-01

466

Tribological evaluation of oxidized zirconium using an articular cartilage counterface: a novel material for potential use in hemiarthroplasty.  

PubMed

Problems with total joint replacement that have surfaced in recent years have made reconsideration of more conservative hip reconstructive procedures compelling. Moreover, procedures such as hemiarthroplasty might benefit from newly developed materials that could provide more favourable tribological performance when employed as a counterface for articulation with articular cartilage. The objective of this study was to evaluate the tribology of a new biomaterial, oxidized zirconium, with articular cartilage in a laboratory test apparatus. Oxidized zirconium components are produced by oxidizing the zirconium alloy to form a relatively thick (7 microns), adherent, abrasion-resistant ceramic surface. We found that the coefficient of friction of bovine articular cartilage rubbed against oxidized zirconium was lower than with cobalt-chromium alloy control surfaces, and that there was a trend toward less wear with oxidized zirconium. A defined layer of degraded tissue was found on the surface of the articular cartilage specimens, providing some indication of the mechanism of wear. Results of this study warrant further investigation of oxidized zirconium as the bearing surface for hemiarthroplasty. PMID:9061186

Patel, A M; Spector, M

1997-03-01

467

40 CFR 97.421 - Recordation of TR NOX Annual allowance allocations and auction results.  

Code of Federal Regulations, 2013 CFR

...TR NOX Annual allowance allocations and auction results. 97.421 Section 97.421...NOX Annual allowance allocations and auction results. (a) By November 7, 2011...By the date on which any allocation or auction results, other than an allocation...

2013-07-01

468

40 CFR 97.711 - Timing requirements for TR SO2 Group 2 allowance allocations.  

Code of Federal Regulations, 2013 CFR

...false Timing requirements for TR SO2 Group 2 allowance allocations. 97.711...CAIR NOX AND SO2 TRADING PROGRAMS TR SO2 Group 2 Trading Program § 97.711 Timing requirements for TR SO2 Group 2 allowance allocations. (a)...

2013-07-01

469

40 CFR 97.712 - TR SO2 Group 2 allowance allocations to new units.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false TR SO2 Group 2 allowance allocations to new units. 97...AND CAIR NOX AND SO2 TRADING PROGRAMS TR SO2 Group 2 Trading Program § 97.712 TR SO2 Group 2 allowance allocations to new units....

2013-07-01

470

40 CFR 97.612 - TR SO2 Group 1 allowance allocations to new units.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false TR SO2 Group 1 allowance allocations to new units. 97...AND CAIR NOX AND SO2 TRADING PROGRAMS TR SO2 Group 1 Trading Program § 97.612 TR SO2 Group 1 allowance allocations to new units....

2013-07-01

471

40 CFR 97.723 - Recordation of TR SO2 Group 2 allowance transfers.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Recordation of TR SO2 Group 2 allowance transfers. 97.723 Section...CAIR NOX AND SO2 TRADING PROGRAMS TR SO2 Group 2 Trading Program § 97.723 Recordation of TR SO2 Group 2 allowance transfers. (a)...

2013-07-01

472

40 CFR 97.622 - Submission of TR SO2 Group 1 allowance transfers.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Submission of TR SO2 Group 1 allowance transfers. 97.622 Section...CAIR NOX AND SO2 TRADING PROGRAMS TR SO2 Group 1 Trading Program § 97.622 Submission of TR SO2 Group 1 allowance transfers. (a) An...

2013-07-01

473

40 CFR 97.724 - Compliance with TR SO2 Group 2 emissions limitation.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Compliance with TR SO2 Group 2 emissions limitation. 97.724 Section...CAIR NOX AND SO2 TRADING PROGRAMS TR SO2 Group 2 Trading Program § 97.724 Compliance with TR SO2 Group 2 emissions limitation. (a)...

2013-07-01

474

40 CFR 97.624 - Compliance with TR SO2 Group 1 emissions limitation.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Compliance with TR SO2 Group 1 emissions limitation. 97.624 Section...CAIR NOX AND SO2 TRADING PROGRAMS TR SO2 Group 1 Trading Program § 97.624 Compliance with TR SO2 Group 1 emissions limitation. (a)...

2013-07-01

475

40 CFR 97.611 - Timing requirements for TR SO2 Group 1 allowance allocations.  

Code of Federal Regulations, 2013 CFR

...false Timing requirements for TR SO2 Group 1 allowance allocations. 97.611...CAIR NOX AND SO2 TRADING PROGRAMS TR SO2 Group 1 Trading Program § 97.611 Timing requirements for TR SO2 Group 1 allowance allocations. (a)...

2013-07-01

476

40 CFR 97.623 - Recordation of TR SO2 Group 1 allowance transfers.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Recordation of TR SO2 Group 1 allowance transfers. 97.623 Section...CAIR NOX AND SO2 TRADING PROGRAMS TR SO2 Group 1 Trading Program § 97.623 Recordation of TR SO2 Group 1 allowance transfers. (a)...

2013-07-01

477

40 CFR 97.722 - Submission of TR SO2 Group 2 allowance transfers.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Submission of TR SO2 Group 2 allowance transfers. 97.722 Section...CAIR NOX AND SO2 TRADING PROGRAMS TR SO2 Group 2 Trading Program § 97.722 Submission of TR SO2 Group 2 allowance transfers. (a) An...

2013-07-01

478

46 CFR 97.37-33 - Instructions for changing steering gear.  

Code of Federal Regulations, 2013 CFR

...false Instructions for changing steering gear. 97.37-33 Section 97.37-33...37-33 Instructions for changing steering gear. (a) Instructions in at least 1...taken in changing to the emergency steering gear. Each clutch, gear, wheel, lever,...

2013-10-01

479

29 CFR 97.12 - Special grant or subgrant conditions for âhigh-riskâ grantees.  

Code of Federal Regulations, 2013 CFR

...Special grant or subgrant conditions for âhigh-riskâ grantees. 97.12 Section 97.12 Labor Office...grant or subgrant conditions for âhigh-riskâ grantees. (a) A grantee or subgrantee may be considered âhigh riskâ...

2013-07-01

480

Absent Student Assistance Program, Precinct 7, 1996-97. Research Report on an Educational Program.  

ERIC Educational Resources Information Center

The Absent Student Assistance Program (ASAP) began as a collaboration between the one Houston (Texas) precinct and two middle schools to reduce unexcused absences. By 1996-97, the program had expanded to a second precinct and additional middle and high schools. Program implementation in Precinct 7 was evaluated for the 1996-97 school year. Schools…

Houston Independent School District, TX. Dept. of Research and Accountability.

481

High transcytosis of melanotransferrin (P97) across the blood-brain barrier  

Microsoft Academic Search

The blood-brain barrier (BBB) performs a neuroprotective function by tightly controlling access to the brain; consequently it also impedes access of proteins as well as pharmacological agents to cerebral tissues. We demonstrate here that recom- binant human melanotransferrin (P97) is highly accumulated into the mouse brain following intravenous injection and in situ brain perfusion. Moreover, P97 transcytosis across bovine brain

Michel Demeule; Julie Poirier; Julie Jodoin; Richard R. Desrosiers; Claude Dagenais; Tran Nguyen; Julie Lanthier; Reinhard Gabathuler; Malcolm Kennard; Wilfred A. Jefferies; Delara Karkan; Sam Tsai; Laurence Fenart; Romeo Cecchelli; Richard Beliveau

482

46 CFR 97.15-15 - Examination of boilers and machinery.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 false Examination of boilers and machinery. 97.15-15 Section...Inspections § 97.15-15 Examination of boilers and machinery. It shall be the duty...chief engineer when assuming charge of the boilers and machinery of a vessel to...

2013-10-01

483

47 CFR 97.31 - Cancellation on account of the licensee's death.  

Code of Federal Regulations, 2013 CFR

...Cancellation on account of the licensee's death. 97.31 Section 97.31 Telecommunication...Cancellation on account of the licensee's death. (a) A person may request cancellation...license grant on account of the licensee's death by submitting a signed request that...

2013-10-01

484

46 CFR 56.97-35 - Pneumatic tests (replaces 137.5).  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Pneumatic tests (replaces 137.5). 56.97-35 Section...ENGINEERING PIPING SYSTEMS AND APPURTENANCES Pressure Tests § 56.97-35 Pneumatic tests (replaces 137.5). (a) General...

2013-10-01

485

Genome Sequence of the Pyrene- and Fluoranthene-Degrading Bacterium Cycloclasticus sp. Strain PY97M  

PubMed Central

Cycloclasticus sp. strain PY97M was isolated from a phenanthrene-degrading consortium, enriched from Yellow Sea sediment of China. Here, we present the draft genome sequence of strain PY97M, which contains 2,359,509 bp with a G+C content of 41.92% and contains 2, 264 protein-coding genes and 40 tRNAs.

Cui, Zhisong; Xu, Guangsu; Li, Qian; Gao, Wei

2013-01-01

486

TART97 a coupled neutron-photon 3-D, combinatorial geometry Monte Carlo transport code  

SciTech Connect

TART97 is a coupled neutron-photon, 3 Dimensional, combinatorial geometry, time dependent Monte Carlo transport code. This code can on any modern computer. It is a complete system to assist you with input preparation, running Monte Carlo calculations, and analysis of output results. TART97 is also incredibly FAST; if you have used similar codes, you will be amazed at how fast this code is compared to other similar codes. Use of the entire system can save you a great deal of time and energy. TART97 is distributed on CD. This CD contains on- line documentation for all codes included in the system, the codes configured to run on a variety of computers, and many example problems that you can use to familiarize yourself with the system. TART97 completely supersedes all older versions of TART, and it is strongly recommended that users only use the most recent version of TART97 and its data riles.

Cullen, D.E.

1997-11-22

487

Extending FEAST-METAL for analysis of low content minor actinide bearing and zirconium rich metallic fuels for sodium fast reactors  

Microsoft Academic Search

Computational models in FEAST-METAL fuel behaviour code have been upgraded to simulate minor actinide bearing zirconium rich metallic fuels for use in sodium fast reactors. Increasing the zirconium content to 20–40wt.% causes significant changes in fuel slug microstructure affecting thermal, mechanical, chemical, and fission gas behaviour. Inclusion of zirconium rich phase reduces the fission gas swelling rate significantly in early

Aydin Karahan

2011-01-01

488

Temporal and spatial expression of Drosophila DLGS97 during neural development.  

PubMed

The products of the Drosophila discs-large (dlg) gene are members of the MAGUK family of proteins, a group of proteins involved in localization, transport and recycling of receptors and channels in cell junctions, including the synapse. In vertebrates, four genes with multiple splice variants homologous to dlg are described. dlg originates two main proteins, DLGA, similar to the vertebrate neuronal protein PSD95, and DLGS97, similar to the vertebrate neuronal and epithelial protein SAP97. DLGA is expressed in epithelia, neural tissue and muscle. DLGS97 is expressed in neural tissue and muscle but not in epithelia. The distinctive difference between them is the presence in DLGS97 of an L27 domain. The differential expression between these variants makes the study of DLGS97 of key relevance to understand the in vivo role of synaptic MAGUKs in neurons. Here we present the temporal and spatial expression pattern of DLGS97 during embryonic and larval nervous system development, during eye development and in adult brain. Our results show that DLGS97 is expressed zygotically, in neurons in the embryo, larvae and adult, and is absent at all stages in glial cells. During eye development DLGS97 starts to be expressed in photoreceptor cells at early stages of differentiation and localizes basal to the basolateral junctions. In the brain, DLGS97 is expressed in the mushroom bodies and optic lobes at larval and adult stages; and in the antennal lobe in the adult stage. In addition we show that both, dlgS97 and dlgA transcripts, express during development multiple splice variants with differences in the use of exons in two sites. PMID:18501681

Albornoz, Valeria; Mendoza-Topaz, Carolina; Oliva, Carlos; Tello, Judith; Olguín, Patricio; Sierralta, Jimena

2008-07-01

489

High temperature mechanical properties of a zirconium-modified, precipitation- strengthened nickel, 30 percent copper alloy  

NASA Technical Reports Server (NTRS)

A precipitation-strengthened Monel-type alloy has been developed through minor alloying additions of zirconium to a base Ni-30Cu alloy. The results of this exploratory study indicate that thermomechanical processing of a solution-treated Ni-30Cu-0.2Zr alloy produced a dispersion of precipitates. The precipitates have been tentatively identified as a Ni5Zr compound. A comparison of the mechanical properties, as determined by testing in air, of the zirconium-modified alloy to those of a Ni-30Cu alloy reveals that the precipitation-strengthened alloy has improved tensile properties to 1200 K and improved stress-rupture properties to 1100 K. The oxidation characteristics of the modified alloy appeared to be equivalent to those of the base Ni-30Cu alloy.

Whittenberger, J. D.

1974-01-01

490

Health hazard evaluation report HETA 93-0501-2580, Western Zirconium, Ogden, Utah  

SciTech Connect

In response to an employee request, an investigation was begun into possible hazardous working conditions at Western Zirconium, Ogden, Utah. The requestor expressed concern over work related asthma and respiratory problems reported among employees at the facility. The company employed 430 workers at the site in the production of zirconium metal parts for use in nuclear power reactors. Records indicated occupational overexposure to hydrogen-chloride and chlorine gas and the sporadic release of hydrofluoric-acid. Spirometry data indicated that five current workers at the site had significant cross sectional changes in their spirometry. Five current workers had longitudinal changes in their spirometry and four had both cross sectional and longitudinal changes. The authors conclude that there was a potential for occupational exposure to respiratory irritants.

Husberg, B.; Berardinelli, S.

1996-05-01

491

The isotopic composition of zirconium in terrestrial and extraterrestrial samples - Implications for extinct Nb-92  

NASA Astrophysics Data System (ADS)

The isotopic composition of zirconium in lunar, meteoritic and old and recent terrestrial samples is analyzed. No isotopic variation is found, although the Zr-92/Zr-90 ratio of 3.8 Ga old zircons from the Isua acid conglomerate is on the lower limit of the range of the standard measurements. The maximum Nb-92/Nb-93 initial ratio at the time of formation of the solar system is 0.007, and thus the maximum sensitivity of the (Nb-92)-(Zr-92) relative radiochronometer for the formation of the planetary bodies is worse than ten million a. A survey of possible nuclear reactions indicates that zirconium isotopic variations in zircons are not easily produced, and that the Nb-92 and Nb-94 natural activities cannot be explained by any single one of the processes proposed thus far.

Minster, J.-F.; Allegre, C. J.

1982-04-01

492

Third column electro-optical coefficients of zirconium-doped congruent lithium niobate crystals  

NASA Astrophysics Data System (ADS)

All coefficients of the third-column of the unclamped and clamped electro-optic tensor of zirconium-doped congruent LiNbO3 single crystals, in the concentration range up to 2.5 mol%, are determined as function of the dopant concentration by direct techniques based on interferometric and Sénarmont optical arrangements at the wavelength of 633 nm and at room temperature. It is found that all the unclamped and clamped electro-optic coefficients are relatively constant, except for the sample doped with 2 mol% of zirconium. From the obtained experimental values, the acoustic contribution is then deduced and found constant over all the studied samples. Finally, the electro-optic behavior of LN:Zr as function of the dopant concentration was confirmed by dielectric characterizations.

Aillerie, Michel; Abarkan, Mustapha; Kostritskii, Sergey; Kokanyan, Edvard

2014-05-01

493

Method to predict relative hydriding within a group of zirconium alloys under nuclear irradiation  

DOEpatents

An out-of-reactor method for screening to predict relative in-reactor hydriding behavior of zirconium-based materials is disclosed. Samples of zirconium-based materials having different compositions and/or fabrication methods are autoclaved in a relatively concentrated (0.3 to 1.0M) aqueous lithium hydroxide solution at constant temperatures within the water reactor coolant temperature range (280 to 316 C). Samples tested by this out-of-reactor procedure, when compared on the basis of the ratio of hydrogen weight gain to oxide weight gain, accurately predict the relative rate of hydriding for the same materials when subject to in-reactor (irradiated) corrosion. 1 figure.

Johnson, A.B. Jr.; Levy, I.S.; Trimble, D.J.; Lanning, D.D.; Gerber, F.S.

1990-04-10

494

Zirconium pressure tube testing: Test procedures, Production Assurance Program (Project H-700)  

SciTech Connect

UNC Nuclear Industries (UNC) has initiated a plan for the fabrication of zirconium alloy pressure tubes required for the future operation of N-Reactor. As part of this plan, UNC is establishing a program to qualify and develop a process capable of fabricating these pressure tubes to the requirements of UNC specification HWS 6502, REV. 4, Amendment 1. The objective of the Pressure Tube Testing Task is to support the UNC program-by performing physical, mechanical and chemical testing on prototype tube sections produced during FY-1986, 1987 and 1988 and to test samples from production runs after 1988 as may be required. The types of tests included in the Zirconium Pressure Tube Testing Program will be as follows: tensile tests; burst tests; fracture toughness tests; corrosion tests; chemical composition analyses; grain structure evaluations. The purpose of this document is to define the procedures that will be used in each type of test included in this task.

Zaloudek, F.R.; Lewis, M. [Pacific Northwest Lab., Richland, WA (United States)

1986-06-01

495

Investigation of neutron radiation effects on the mechanical behavior of recrystallized zirconium alloys  

NASA Astrophysics Data System (ADS)

Neutron radiation induces important changes in the mechanical behavior of recrystallized zirconium alloys used as fuel cladding tube. The neutron radiation effects on the mechanical behavior for internal pressure tests performed at 350 °C have been investigated using a specific analysis in terms of isotropic hardening, kinematic hardening and viscous stress. A unified internal variables modeling has also been used in order to provide a consistent description of the radiation effects on the mechanical behavior. The impact of irradiation has been interpreted in terms of microscopic deformation mechanisms observed by transmission electron microscopy. Due to the localization of the plastic deformation inside channels and because of the only activation of basal channeling, the kinematic hardening is expected to be strong in irradiated zirconium alloys.

Onimus, F.; Béchade, J. L.; Duguay, C.; Gilbon, D.; Pilvin, P.

2006-11-01

496

A polycrystalline modeling of the mechanical behavior of neutron irradiated zirconium alloys  

NASA Astrophysics Data System (ADS)

Zirconium alloys used as fuel cladding tubes in the nuclear industry undergo important changes after neutron irradiation in the microstructure as well as in the mechanical properties. However, the effects of the specific post-irradiation deformation mechanisms on the mechanical behavior are not clearly understood and modeled. Based on experimental results it is discussed that the kinematic strain hardening is increased by the plastic strain localization inside the dislocation channels as well as the only basal slip activation observed for specific mechanical tests. From this analysis, the first polycrystalline model is developed for irradiated zirconium alloys, taking into account the irradiation induced hardening, the intra-granular softening as well as the intra-granular kinematic strain hardening due to the plastic strain localization inside the channels. This physically based model reproduces the mechanical behavior in agreement with the slip systems observed. In addition, this model reproduces the Bauschinger effect observed during low cycle fatigue as well as the cyclic strain softening.

Onimus, Fabien; Béchade, Jean-Luc

2009-02-01

497

Method to predict relative hydriding within a group of zirconium alloys under nuclear irradiation  

DOEpatents

An out-of-reactor method for screening to predict relative in-reactor hydriding behavior of zirconium-bsed materials is disclosed. Samples of zirconium-based materials having different composition and/or fabrication are autoclaved in a relatively concentrated (0.3 to 1.0M) aqueous lithium hydroxide solution at constant temperatures within the water reactor coolant temperature range (280.degree. to 316.degree. C.). Samples tested by this out-of-reactor procedure, when compared on the basis of the ratio of hydrogen weight gain to oxide weight gain, accurately predict the relative rate of hyriding for the same materials when subject to in-reactor (irradiated) corrision.

Johnson, Jr., A. Burtron (Richland, WA); Levy, Ira S. (Kennewick, WA); Trimble, Dennis J. (Kennewick, WA); Lanning, Donald D. (Kennewick, WA); Gerber, Franna S. (Richland, WA)

1990-01-01

498

Wet Etching of Heat Treated Atomic Layer Chemical Vapor Deposited Zirconium Oxide in HF Based Solutions  

NASA Astrophysics Data System (ADS)

Alternative materials are being considered to replace silicon dioxide as gate dielectric material. Of these, the oxides of hafnium and zirconium show the most promise. However, integrating these new high-k materials into the existing complementary metal-oxide-semiconductor (CMOS) process remains a challenge. One particular area of concern is the wet etching of heat treated high-k dielectrics. In this paper, work done on the wet etching of heat treated atomic layer chemical vapor deposited (ALCVD) zirconium oxide in HF based solutions is presented. It was found that heat treated material, while refractory to wet etching at room temperature, is more amenable to etching at higher temperatures when methane sulfonic acid is added to dilute HF solutions. Selectivity over SiO2 is still a concern.

Balasubramanian, Sriram; Raghavan, Srini

2008-06-01

499

Effect of competitive ions on the arsenic removal by mesoporous hydrous zirconium oxide from drinking water  

SciTech Connect

Adsorption properties of 302-type commercially available hydrous zirconium oxide (302-HZO) towards arsenic and some competitive anions and cations have been studied under batch and column conditions. Due to amphoteric properties, anion exchange performance of hydrous zirconium oxide is pH dependent. Media exhibits high affinity towards arsenic in a broad pH range, with high adsorption capacity at pH < 8. It was shown that silicate and phosphate ions are arsenic's main competitors affecting media adsorption capacity. Presence of transition metal cations in <1 ppm does not affect 302-HZO capacity on arsenic, whereas alkaline-earth cations improve arsenic removal. The possibility for significant increase of 302-HZO adsorption capacity on arsenic at pH > 8 by using 'solid acidifier' technique is discussed. Results of 302-HZO field trials are presented.

Bortun, Anatoly; Bortun, Mila; Pardini, James [MEL Chemicals Inc., 500 Barbertown Point Breeze Road, Flemington, NJ 08822 (United States)] [MEL Chemicals Inc., 500 Barbertown Point Breeze Road, Flemington, NJ 08822 (United States); Khainakov, Sergei A. [Departamento de Quimica Organica e Inorganica, Universidad de Oviedo, C/ Julian Claveria, 8, 33006 Oviedo (Spain)] [Departamento de Quimica Organica e Inorganica, Universidad de Oviedo, C/ Julian Claveria, 8, 33006 Oviedo (Spain); Garcia, Jose R., E-mail: jrgm@uniovi.es [Departamento de Quimica Organica e Inorganica, Universidad de Oviedo, C/ Julian Claveria, 8, 33006 Oviedo (Spain)

2010-11-15

500

Solid-State diffusion reaction and formation of intermetallic compounds in the nickel-zirconium system  

NASA Astrophysics Data System (ADS)

Chemical diffusion studies in the nickel-zirconium system are investigated in the temperature range of 1046 to 1213 K employing diffusion couples of pure nickel and pure zirconium. Electron microprobe and X-ray diffraction studies have been employed to investigate the formation of different compounds and to study their layer growth kinetics in the diffusion zone. It is observed that growth of each phase is controlled by the process of volume diffusion as the layer growth obeys the parabolic law. The activation energies for interdiffusion in NiZr and NiZr2, which are the dominant phases in the diffusion zone, are 119.0 ±13.4 and 103.0 ±25.0 kJ/ mole, respectively. The formation and stability of compounds over the temperature range have been discussed on the basis of existing thermodynamic and kinetic data.

Bhanumurthy, K.; Kale, G. B.; Khera, S. K.; Asundi, M. K.

1990-11-01