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1

Molten Salt Oxidation of Ion-exchange Resins Doped with Toxic Metals and Radioactive Metal Surrogates  

Microsoft Academic Search

Ion-exchange resins doped with toxic metals and radioactive metal surrogates were test-burned in a bench-scale molten salt oxidation (MSO) reactor system. The purposes of this study are to confirm the destruction performance of the two-stage MSO reactor system for the organic ion-exchange resin and to obtain an understanding of the behavior of the fixed toxic metals and the sulfur in

Hee-Chul YANG; Yong-Jun CHO; Hee-Chul EUN; Jae-Hyung YOO; Joon-Hyung KIM

2005-01-01

2

Development of materials for the removal of metal ions from radioactive and non-radioactive waste streams  

NASA Astrophysics Data System (ADS)

Nuclear wastes that were generated during cold-war era from various nuclear weapon programs are presently stored in hundreds of tanks across the United States. The composition of these wastes is rather complex containing both radionuclides and heavy metals, such as 137Cs, 90Sr, Al, Pb, Cr, and Cd. In this study, chitosan based biosorbents were prepared to adsorb some of these metal ions. Chitosan is a partially acetylated glucosamine biopolymer encountered in the cell walls of fungi. In its natural form this material is soft and has a tendency to agglomerate or form gels. Various methods were used to modify chitosan to avoid these problems. Chitosan is generally available commercially in the form of flakes. For use in an adsorption system, chitosan was made in the form of beads to reduce the pressure drop in an adsorption column. In this research, spherical beads were prepared by mixing chitosan with perlite and then by dropwise addition of the slurry mixture into a NaOH precipitation bath. Beads were characterized using Fourier Transform InfraRed Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Energy dispersive spectroscopy (EDS), Tunneling Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), and Thermogravimetric Analysis (TGA). The SEM, EDS, and TEM data indicated that the beads were porous in nature. The TGA data showed that bead contained about 32% chitosan. The surface area, pore volume, and porosity of the beads were determined from the BET surface area that was measured using N2 as adsorbate at 77K. Adsorption and desorption of Cr(VI), Cr(III), Cd(II), U(VI), Cu(II), from aqueous solutions of these metal ions were studied to evaluate the adsorption capacities of the beads for these metals ions. Equilibrium adsorption data of these metals on the beads were found to correlate well with the Langmuir isotherm equation. Chitosan coated perlite beads had negligible adsorption capacity for Sr(II) and Cs(I). It was found that Fullers earth had very good capacity for these two metals. However, the mechanical strength of Fullers earth granules available commercially was not sufficient for use in a column. In this study chitosan was used as a binder to make Fullers earth beads and were used for adsorption of Cs(I) and Sr(II). (Abstract shortened by UMI.)

Hasan, Md. Shameem

3

Removal of Radioactive Cesium from Nuclear Waste Solutions with the Transition Metal Hexacyanoferrate Ion Exchanger CsTreat  

SciTech Connect

A transition metal hexacyanoferrate product CsTreat has been utilized at industrial scale for radioactive cesium separation at several nuclear power plants (NPPs) in several countries. A granular hexacyanoferrate ion exchanger has been used in packed-bed column mode operations for the removal of cesium from a variety of wastewater types. CsTreat beds have successfully purified both high-salt evaporator concentrates and dilute floor drain waters at NPPs in Finland and the United States. Furthermore, medium-active reprocessing solutions, containing high concentrations of sodium nitrate, have been decontaminated by a CsTreat bed at the Japan Atomic Energy Research Institute. These solutions are described as are other industrial applications of this ion exchange material, which, of all the commercial materials, has been shown to be the most selective exchanger for cesium. In addition, some prospective fields of hexacyanoferrate utilization, such as the use of CsTreat powder in a precoat filtration system, are discussed.

Harjula, R. [University of Helsinki (Finland); Lehto, J. [University of Helsinki (Finland); Paajanen, A. [University of Helsinki (Finland); Brodkin, L. [University of Helsinki (Finland); Tusa, E. [Fortum Engineering (Finland)

2001-02-15

4

A multicusp ion source for radioactive ion beams  

Microsoft Academic Search

In order to produce a radioactive ion beam of 14O+ , a 10 cm-diameter, 13.56 MHz radio frequency (RF) driven multicusp ion source is now being developed at Lawrence Berkeley National Laboratory. In this paper we describe the ion source performance with respect to its capability as an ion source for radioactive ion beam (RIB) production using Ar, Xe and

D. C. Wutte; Y. Lee; M. A. Leitner; M. D. Williams; K. N. Leung; R. A. Gough; S. J. Freedman; Z. Q. Xie; C. M. Lyneis

1997-01-01

5

Decontaimination of radioactive metals  

SciTech Connect

This patent describes a method of extracting technetium and actinide radiocontaminants from radiocontaminated nickel comprising the steps: fabricating a nickel electrode contaminated with technetium and actinides; and then anodically dissolving the electrode contaminated with technetium and actinides in a oxidizing acid electrolyte solution to produce a solution containing actinide ions and at least 30 grams/liter of nickel and to oxidize the technetium to produce pertechnetate anions; and then removing pertechnetate anions and actinides by counter-current solvent extraction with a barren solution containing TOPO, D[sub 2]EHPA or mixtures thereof dissolved in an organic solvent, to produce a decontaminated, nickel containing raffinate, and a contaminated, loaded solvent stream; and then stripping the technetium values from the contaminated, loaded solvent stream with hydrochloric acid; passing the decontaminated, nickel containing raffinate through an absorbent for organic solvent; and then electrowinning the raffinate in an electrolysis cell with acidic electrolyte to remove residual actinides present, and to recover cathodic nickel.

Snyder, T.S.; Gass, W.R.; Worcester, S.A.; Ayers, L.J.

1992-10-20

6

Metal Ion Sources for Ion Beam Implantation  

SciTech Connect

In this paper a theme touched upon the progress of metal ion sources devoted to metal ion beam implantation (MIBI) will be reviewed. A special emphasis will be given to some kinds of ion sources such as ECR, MEVVA and Cluster ion sources. A novel dual hollow cathode metal ion source named DUHOCAMIS will be introduced and discussed.

Zhao, W. J.; Zhao, Z. Q.; Ren, X. T. [Institute of Heavy Ion Physics and State Key Labarotary in Nuclear Physics and Nuclear Technology, Peking University, Beijing 100871 (China)

2008-11-03

7

Removal of Radioactive Heavy Metal Ions From Solution by Superconducting High-Gradient Magnetic Separation With Schwertmannite and Zirconium-Ferrite Adsorbents  

Microsoft Academic Search

Schwertmannite, i.e. iron oxyhydroxysulfate and zirconium-ferrite particles are excellent adsorbents for uranium ions. The magnetic separation characteristics for removal of radioactive ions, i.e. uranium and radium ions, from solution with the adsorbents of synthesized schwertmannite and the zirconium-ferrite particles have been studied. By a 10 tesla superconducting high-gradient magnetic separator, 10 ppb uranium ions in sample solution could be reduced

Kenji Nishimura; Osuke Miura; Daisuke Ito; Yasumichi Tsunasima; Yukio Wada

2009-01-01

8

Metal Ions in Unusual Valency States.  

ERIC Educational Resources Information Center

Discusses reactivity of metal ions with the primary products of water radiolysis, hyper-reduced metal ions, zero-valent metal ions, unstable divalent ions from the reduction of bivalent ions, hyper-oxidized metal ions, and metal complexes. (CS)

Sellers, Robin M.

1981-01-01

9

Ultraviolet metal ion laser  

SciTech Connect

A metal ion laser is described comprising: a cylindrical vacuum enclosure having a longitudinal axis that is coincident with an unobstructed longitudinal optical axis defined by a resonant optical cavity comprising two mirrors, one at each end thereof, one or both of which mirrors are employed to extract poser from the laser; a cylindrical magnetron sputtering source positioned coaxially with an adjacent to the cylindrical vacuum enclosure; two annular shaped cold cathodes each having diameter substantially equal to the diameter of the cylindrical vacuum enclosure and the two cylindrical anodes; power supply means electrically connected to the metal ion laser for causing the cylindrical magnetron sputtering source to sputter metal vapor from the cylindrical metal cathode tube and for creating rare gas ions.

Collins, G.J.; McNeil, J.R.

1988-03-08

10

Radioactive ion beam line in Lanzhou  

Microsoft Academic Search

Radioactive ion beam line in Lanzhou (RIBLL) has been constructed for the production of short-lived radioactive nuclei and\\u000a studies of exotic nuclei far from the ?-stability line. It has been put into operation recently at the National Laboratory\\u000a of Heavy Ion Accelerator Lanzhou. RIBLL consists of two doubly achromatic parts with a solid acceptance ???6.5 msr, momentum\\u000a acceptance ?p\\/p=±5% and

Wenlong Zhan; Zhongyan Guo; Guanhua Liu; Jianrong Dang; Ruirong He; Sixin Zhou; Quanmin Yin; Yixiao Luo; Yifang Wang; Baowen Wei; Zhiyu Sun; Guoqing Xiao; Jinchuan Wang; Shanhong Jiang; Jiaxing Li; Xiangwei Meng; Wansheng Zhang; Lijun Qing; Quanjin Wang

1999-01-01

11

Method for decontamination of radioactive metal surfaces  

DOEpatents

Disclosed is a method for removing radioactive contaminants from metal surfaces by applying steam containing an inorganic acid and cerium IV. Cerium IV is applied to contaminated metal surfaces by introducing cerium IV in solution into a steam spray directed at contaminated metal surfaces. Cerium IV solution is converted to an essentially atomized or vapor phase by the steam.

Bray, L.A.

1996-08-13

12

Survey of Radioactivities Induced by Lithium Ions.  

National Technical Information Service (NTIS)

Lithium-induced nuclear reactions which lead to radioactivities are surveyed for application to experiments with intense lithium-ion beams from pulsed power generators. Positive Q-value reactions for 7Li ions of up to 15 MeV on carbon, aluminum, steel, br...

F. C. Young D. V. Rose

1992-01-01

13

Tokai Radioactive Ion Accelerator Complex (TRIAC)  

NASA Astrophysics Data System (ADS)

An ISOL-based radioactive nuclear beam (RNB) facility, Tokai Radioactive Ion Accelerator Complex (TRIAC), has been jointly developed by High Energy Accelerator Research Organization (KEK) and Japan Atomic Energy Agency (JAEA). The facility started to supply RNBs for experiments in 2005 and RNBs including fission fragments with energies up to 1.1MeV/A are available in the present. Several experimental studies were performed successfully using 8Li beams with various energies.

Watanabe, Y. X.; Arai, S.; Arakaki, Y.; Fuchi, Y.; Hirayama, Y.; Imai, N.; Ishiyama, H.; Jeong, S. C.; Kawakami, H.; Miyatake, H.; Niki, K.; Nomura, T.; Okada, M.; Oyaizu, M.; Tanaka, M. H.; Tomizawa, M.; Yoshikawa, N.; Abe, S.; Hanashima, S.; Hashimoto, T.; Ichikawa, S.; Ikezoe, H.; Ishii, T.; Ishizaki, N.; Kabumoto, H.; Katayama, I.; Koizumi, M.; Matsuda, M.; Mitsuoka, S.; Nakanoya, T.; Nishio, K.; Ohuchi, I.; Osa, A.; Sato, T. K.; Takeuchi, S.; Tayama, H.; Tsukihashi, Y.

2007-11-01

14

Radioactive-ion-beam research at Livermore  

NASA Astrophysics Data System (ADS)

The ability to produce secondary radioactive heavy ion beams which can be isolated, focused, and transported to a secondary target can enable reaction studies and other research with the approximately more than 1300 nuclei with decay lifetimes approximately more than 1 microsec. Current research in secondary beam production and future applications in astrophysics, nuclear structure, heavy ion physics, and radiotherapy are examined as well as associated spin off and technology transfer in applied physics.

Haight, R. C.; Mathews, G. J.; Ward, R. A.; Woosley, S. E.

1983-06-01

15

Status of the Holifield Radioactive Ion Beam Facility.  

National Technical Information Service (NTIS)

The Holifield Radioactive Ion Beam Facility received authorization in December 1996 to commence routine operation as a National User Facility. Significant progress has been made toward the goal of providing high-quality radioactive ion beams. The task of ...

M. J. Meigs

2001-01-01

16

Advances in metal ion sources  

SciTech Connect

Beams of metallic ion species can be produced by the ECR (electron cyclotron resonance) ion source and by the MEVVA (metal vapor vacuum arc) ion source. Although the ECR source is fundamentally a gaseous ion source, metal ion beams can be produced by introducing metallic feed material into the plasma discharge using a number of techniques. The ion charge states can be very high, which is a significant advantage to most applications. The MEVVA ion source, on the other hand, is specifically a metal ion source. It has produced metallic ion beams from virtually all the solid metallic elements at a current of typically hundreds of milliamperes; the ions produced are in general multiply ionized, but not as highly stripped as those generated in the ECR source. Although the MEVVA source at present operates in a pulsed mode with a low duty cycle (less than or equal to 1%), work is in progress to increase the duty cycle significantly. In this paper the operation and performance of the LBL ECR and MEVVA ion sources, with respect to metal ion generation, are described.

Brown, I.G.

1988-05-01

17

A Novel Radioactive Isotope Ion Target SCRIT  

NASA Astrophysics Data System (ADS)

Electron scattering is a superior method to investigate the internal structure, such as charge distribution, of atomic nuclei. Most of the radii of nuclei were determined unambiguously by that. However, radioactive isotopes (RI) which recently came up to a major research interest have not been accessible due to the difficulty in making fixed targets and taking measurements before they decay. We proposed a conceptually new target called SCRIT (Self-Confining Radioactive Isotope ion Target) as opposed to a collider method. The luminosity expected for SCRIT is inevitably low (typically on the order of 1.E+27/cm2/s) and a large acceptance detector system is required. We plan to perform a coincidence measurement using an electron arm and a recoil ion detector which needs to be developed. Current status of the ion trapping with a prototype SCRIT and the background measurement results in an electron storage ring will be discussed.

Kurita, Kazuyoshi; Masuda, Tetsuya; Koseki, Tadashi; Noda, Akira; Shirai, Toshiyuki; Tongu, Hiromu; Furukawa, Yukihiro; Tamae, Tadaaki; Ito, Sachiko; Ohnishi, Tetsuya; Suda, Toshimi; Takeda, Hiroyuki; Wang, Shuo; Emoto, Takashi; Nakamura, Masato; Wakasugi, Masanori; Yano, Yasushige

2006-11-01

18

Radioactive scrap metal decontamination technology assessment report  

SciTech Connect

Within the DOE complex there exists a tremendous quantity of radioactive scrap metal. As an example, it is estimated that within the gaseous diffusion plants there exists in excess of 700,000 tons of contaminated stainless steel. At present, valuable material is being disposed of when it could be converted into a high quality product. Liquid metal processing represents a true recycling opportunity for this material. By applying the primary production processes towards the material`s decontamination and re-use, the value of the strategic resource is maintained while drastically reducing the volume of material in need of burial. Potential processes for the liquid metal decontamination of radioactively contaminated metal are discussed and contrasted. Opportunities and technology development issues are identified and discussed. The processes compared are: surface decontamination; size reduction, packaging and burial; melting technologies; electric arc melting; plasma arc centrifugal treatment; air induction melting; vacuum induction melting; and vacuum induction melting and electroslag remelting.

Buckentin, J.M.; Damkroger, B.K.; Schlienger, M.E. [Sandia National Labs., Albuquerque, NM (United States). Liquid Metal Processing Lab.

1996-04-01

19

Tokai Radioactive Ion Accelerator Complex (TRIAC)  

Microsoft Academic Search

.  \\u000a An ISOL-based radioactive nuclear beam (RNB) facility,\\u000a Tokai Radioactive Ion Accelerator Complex (TRIAC),\\u000a has been jointly developed\\u000a by High Energy Accelerator Research Organization (KEK)\\u000a and Japan Atomic Energy Agency (JAEA).\\u000a The facility started to supply RNBs for experiments in 2005\\u000a and RNBs including fission fragments with energies up to 1.1MeV\\/A\\u000a are available in the present.\\u000a Several experimental studies were

Y. X. Watanabe; S. Arai; Y. Arakaki; Y. Fuchi; Y. Hirayama; N. Imai; H. Ishiyama; S. C. Jeong; H. Kawakami; H. Miyatake; K. Niki; T. Nomura; M. Okada; M. Oyaizu; M. H. Tanaka; M. Tomizawa; N. Yoshikawa; S. Abe; S. Hanashima; T. Hashimoto; S. Ichikawa; H. Ikezoe; T. Ishii; N. Ishizaki; H. Kabumoto; I. Katayama; M. Koizumi; M. Matsuda; S. Mitsuoka; T. Nakanoya; K. Nishio; I. Ohuchi; A. Osa; T. K. Sato; S. Takeuchi; H. Tayama; Y. Tsukihashi

2007-01-01

20

Immobilized metal ion affinity chromatography  

Microsoft Academic Search

This article describes the technique of immobilized metal ion affinity chromatography (1MAC). The IMAC stationary phases are\\u000a designed to chelate certain metal ions that have selectivity for specific groups in peptides and on protein surfaces. The\\u000a number of stationary phases that can be synthesized for efficient chclation of metal ions is unlimited, but the critical consideration\\u000a is that there is

Tai-Tung Yip; T. William Hutchens

1994-01-01

21

Resonant Ionization Laser Ion Source for Radioactive Ion Beams  

SciTech Connect

A resonant ionization laser ion source based on all-solid-state, tunable Ti:Sapphire lasers is being developed for the production of pure radioactive ion beams. It consists of a hot-cavity ion source and three pulsed Ti:Sapphire lasers operating at a 10 kHz pulse repetition rate. Spectroscopic studies are being conducted to develop ionization schemes that lead to ionizing an excited atom through an auto-ionization or a Rydberg state for numerous elements of interest. Three-photon resonant ionization of 12 elements has been recently demonstrated. The overall efficiency of the laser ion source measured for some of these elements ranges from 1 to 40%. The results indicate that Ti:Sapphire lasers could be well suited for laser ion source applications. The time structures of the ions produced by the pulsed lasers are investigated. The information may help to improve the laser ion source performance.

Liu, Yuan [ORNL; Beene, James R [ORNL; Havener, Charles C [ORNL; Vane, C Randy [ORNL; Gottwald, T. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Wendt, K. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Mattolat, C. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Lassen, J. [TRIUMF, Canada

2009-01-01

22

BEARS: Radioactive ion beams at LBNL  

SciTech Connect

BEARS (Berkeley Experiments with Accelerated Radioactive Species) is an initiative to develop a radioactive ion-beam capability at Lawrence Berkeley National Laboratory. The aim is to produce isotopes at an existing medical cyclotron and to accelerate them at the 88 inch Cyclotron. To overcome the 300-meter physical separation of these two accelerators, a carrier-gas transport system will be used. At the terminus of the capillary, the carrier gas will be separated and the isotopes will be injected into the 88 inch Cyclotron`s Electron Cyclotron Resonance (ECR) ion source. The first radioactive beams to be developed will include 20-min {sup 11}C and 70-sec {sup 14}O, produced by (p,n) and (p,{alpha}) reactions on low-Z targets. A test program is currently being conducted at the 88 inch Cyclotron to develop the parts of the BEARS system. Preliminary results of these tests lead to projections of initial {sup 11}C beams of up to 2.5 {times} 10{sup 7} ions/sec and {sup 14}O beams of 3 {times} 10{sup 5} ions/sec.

Powell, J.; Guo, F.Q. [Lawrence Berkeley National Lab., CA (United States); Haustein, P.E. [Brookhaven National Lab., Upton, NY (United States). Chemistry Dept.] [and others

1998-07-01

23

Laser ion sources for radioactive beams (invited)  

NASA Astrophysics Data System (ADS)

Resonant ionisation laser ion sources are nowadays extensively used, when available, at many leading on-line facilities. Moreover, new laser ion sources are now under development in most of the recent on-line facility projects under construction worldwide. This success is mainly due to the reliability, the ionization efficiency and the high purity that this type of source can achieve for the production of radioactive species and for a large range of chemical elements. Laser ion sources for radioactive beams gather many different systems such as dye laser or all-solid state titanium:sapphire laser systems, high or low repetition rates, hot cavities or gas cells, additional selectivity by using chemical techniques, or the LIST technique (laser ion source trap). In this paper, the physics of laser ion sources will be described with the current limitations and challenges for the future. An overview of the laser ion source facilities will be given, with an emphasis on the ongoing developments and perspectives on LIS.

Lecesne, N.

2012-02-01

24

Snowballs of radioactive ions — nuclear spin polarization of core ions  

Microsoft Academic Search

Short-lived ions12B (beta-radioactive, T1\\/2=20.3 ms) sustaining nuclear spin polarization were introduced into superfluid helium at 1.7 K. It was found that the12B ions were transported as charged entities under a static electric field and that the nuclear polarization was maintained throughout the lifetime of12B nuclei. Polarization of12B was determined through beta-NMR method. “Snowball”, a singly charged microcluster of helium atoms

N. Takahashi; T. Shimoda; Y. Fujita; T. Itahashi; H. Miyatake

1995-01-01

25

BEARS: Radioactive Ion Beams at Berkeley  

SciTech Connect

A light-isotope radioactive ion beam capability has been added to the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory by coupling to the production cyclotron of the Berkeley Isotope Facility. The connection required the development and construction of a 350 m gas transport system between the two accelerators as well as automated cryogenic separation of the produced activity. The first beam developed, {sup 11}C, has been successfully accelerated with an on-target intensity of 1 x 10{sup 8} ions/sec at energies of around 10 MeV/u.

Powell, J.; Joosten, R.; Donahue, C.A.; Fairchild, R.F.; Fujisawa, J.; Guo, F.Q.; Haustein, P.E.; Larimer, R.-M.; Lyneis, C.M.; McMahan, M.A.; Moltz, D.M.; Norman, E.B.; O'Neil, J.P.; Ostas, M.A.; Rowe, M.W.; VanBrocklin, H.F.; Wutte, D.; Xie, Z.Q.; Xu, X.J.; Cerny, Joseph

2000-03-14

26

Radioactive Ion Beams at INFN Laboratories  

SciTech Connect

The LNS and the LNL are the two laboratories of INFN devoted to the research on nuclear physics. Since the 1995 the LNS are involved in the design and construction of the Radioactive Ion Beam facilities called EXCYT. In the early of 2000 the LNL starts a project for second generation RIB facilities called SPES. In the 2004 at the LNS we start also the production of RIB by in flight fragmentation. Here the status and perspective of these three projects are presented.

Calabretta, L.; Celona, L.; Chines, F.; Cosentino, L.; Cuttone, G.; Finocchiaro, P.; Maggiore, M.; Pappalardo, A.; Piazza, L.; Re, M.; Rifuggiato, D.; Rovelli, A.; Pappalardo, A. [INFN Laboratori Nazionali del Sud, Via S. Sofia 62, 95123 Catania (Italy); Andrighetto, A.; Prete, G.; Biasetto, L.; Manzolaro, M.; Sarchiapone, L.; Galata, A.; Lombardi, A. [INFN Laboratori Nazionali di Legnaro, Via Romea 6, 35020 Legnaro (Italy)

2010-04-30

27

Laser ion source development at Holifield Radioactive Ion Beam Facility  

NASA Astrophysics Data System (ADS)

This report describes the efforts made to develop a resonant-ionization laser ion source based on tunable Ti:sapphire lasers for nuclear physics and astrophysics research at Holifield Radioactive Ion Beam Facility. Three Ti:sapphire lasers have been upgraded with individual pump lasers to eliminate laser power losses due to synchronization delays. Ionization schemes for 14 elements have been obtained. Off-line studies show that the overall efficiency of the laser ion source can be as high as 40%. TaC surface coatings have been investigated for minimizing surface and bulk trapping of the atoms of interest.

Liu, Y.; Gottwald, T.; Havener, C. C.; Howe, J. Y.; Kiggans, J.; Mattolat, C.; Vane, C. R.; Wendt, K.; Beene, J. R.

2012-02-01

28

Laser ion source development at Holifield Radioactive Ion Beam Facility  

SciTech Connect

This report describes the efforts made to develop a resonant-ionization laser ion source based on tunable Ti:sapphire lasers for nuclear physics and astrophysics research at Holifield Radioactive Ion Beam Facility. Three Ti:sapphire lasers have been upgraded with individual pump lasers to eliminate laser power losses due to synchronization delays. Ionization schemes for 14 elements have been obtained. Off-line studies show that the overall efficiency of the laser ion source can be as high as 40%. TaC surface coatings have been investigated for minimizing surface and bulk trapping of the atoms of interest.

Liu, Y.; Havener, C. C.; Beene, J. R. [Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Gottwald, T.; Mattolat, C.; Vane, C. R.; Wendt, K. [Institute of Physics, University of Mainz, D-55099 Mainz (Germany); Howe, J. Y.; Kiggans, J. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

2012-02-15

29

BEARS: radioactive ion beams at LBNL  

SciTech Connect

BEARS is an initiative to develop a radioactive ion-beam capability at Lawrence Berkeley National Laboratory. The aim is to produce isotopes at an existing medical cyclotron and to accelerate them at the 88'' Cyclotron. To overcome the 300-meter physical separation of these two accelerators, a carrier-gas transport system will be used. At the terminus of the capillary, the carrier gas will be separated and the isotopes will be injected into the 88'' Cyclotron's Electron Cyclotron Resonance (ECR) ion source. The first radioactive beams to be developed will include 20-min {sup 11}C and 70-sec {sup 14}O, produced by (p,n) and (p, {alpha}) reactions on low-Z targets. A test program is currently being conducted at the 88'' Cyclotron to develop the parts of the BEARS system. Preliminary results of these tests lead to projections of initial {sup 11}C beams of up to 2.5x10{sup 7} ions/sec and {sup 14}O beams of 3x10{sup 5} ions/sec.

Powell, J.; Guo, F. Q.; Joosten, R.; Larimer, R.-M.; Lyneis, C.; Moltz, D. M.; Norman, E. B.; O'Neil, J. P.; Rowe, M. W.; VanBrocklin, H. F.; Xie, Z. Q.; Xu, X. J.; Cerny, Joseph [Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720 (United States); Haustein, P. E. [Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973 (United States)

1998-12-21

30

BEARS: radioactive ion beams at LBNL  

SciTech Connect

BEARS is an initiative to develop a radioactive ion-beam capability at Lawrence Berkeley National Laboratory. The aim is to produce isotopes at an existing medical cyclotron and to accelerate them at the 88{sup {double_prime}} Cyclotron. To overcome the 300-meter physical separation of these two accelerators, a carrier-gas transport system will be used. At the terminus of the capillary, the carrier gas will be separated and the isotopes will be injected into the 88{sup {double_prime}} Cyclotron{close_quote}s Electron Cyclotron Resonance (ECR) ion source. The first radioactive beams to be developed will include 20-min {sup 11}C and 70-sec {sup 14}O, produced by (p,n) and (p, {alpha}) reactions on low-Z targets. A test program is currently being conducted at the 88{sup {double_prime}} Cyclotron to develop the parts of the BEARS system. Preliminary results of these tests lead to projections of initial {sup 11}C beams of up to 2.5{times}10{sup 7}ions/sec and {sup 14}O beams of 3{times}10{sup 5}ions/sec. {copyright} {ital 1998 American Institute of Physics.}

Powell, J.; Guo, F.Q.; Joosten, R.; Larimer, R.-M.; Lyneis, C.; Moltz, D.M.; Norman, E.B.; O`Neil, J.P.; Rowe, M.W.; VanBrocklin, H.F.; Xie, Z.Q.; Xu, X.J.; Cerny, Joseph [Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720 (United States)] Haustein, P.E. [Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973 (United States)

1998-12-01

31

Isobar Separators for Radioactive Ion Beam Facilities  

SciTech Connect

A radioactive ion beam facility - in short a RIB facility - produces ions of short-lived nuclei and accelerates them to energies of 0.1?10 MeV per nucleon or even higher. In this process it is important that the resulting RIB beams are free from nuclei of neighboring isobars or of neighboring elements. This task requires the production and ionization of the nuclei of interest as well as separating them from all others with a high-mass resolving power and small-mass cross contaminations. When constructing such a facility it also is very important to find ways that allow the accelerated ions to be provided to different experiments at least quasi simultaneously.

Garrett, J.D.; Wollnik, H.

1998-10-05

32

Fabrication of radioactive stents by ion implantation  

NASA Astrophysics Data System (ADS)

Worldwide about one million patients require treatment of stenosed coronary arteries annually. Often a tubular stainless steel mesh (stent) is implanted to mechanically support the injured vessel. Restenosis, an abundant complication (20%-30%) can be prevented, if the vessel is treated with ionizing radiation. Stents can deliver radiation if they are made radioactive. The radio isotope 32P is well suited when ion implanted. Radioactive ions sources require high efficiency to keep the radioactive inventory small. Reliability, ease of operation, and maintenance are mandatory. A small emittance is important to minimize losses during mass separation and beam transport. A 2.45 GHz ECR source was developed for the implantation of 32P. The source consists of two coils for the axial and a permanent hexapole for the radial confinement. The microwaves are fed in radially by a loop connected to a silver plated brass tube surrounding the plasma chamber. The plasma chamber is made from Pyrex. Neutron activated phosphorus, containing 30 ppm 32P, is introduced from the rear end on a rod. As support gas D2 is used. By this 32P+ can be separated from (31PD)+. The extraction is done in two steps: 60 kV-30 kV-ground. Mass separation is accomplished by a double focusing 90° magnet (radius 500 mm). During four years of operation about 1000 radioactive stents per year have been provided for animal experiments and clinical trials. Only one maintenance to exchange the extraction system due to degradation of high voltage stability was required so far.

Huttel, Erhard; Kaltenbaek, Johann; Schloesser, Klaus; Schweickert, Hermann

2002-02-01

33

Method for electrochemical decontamination of radioactive metal  

DOEpatents

A decontamination method for stripping radionuclides from the surface of stainless steel or aluminum material comprising the steps of contacting the metal with a moderately acidic carbonate/bicarbonate electrolyte solution containing sodium or potassium ions and thereafter electrolytically removing the radionuclides from the surface of the metal whereby radionuclides are caused to be stripped off of the material without corrosion or etching of the material surface.

Ekechukwu, Amy A. (Augusta, GA)

2008-06-10

34

Status of the radioactive ion beam injector at the Holifield Radioactive Ion Beam Facility  

SciTech Connect

The Holifield Radioactive Ion Beam Facility (HRIBF) is a first generation radioactive ion beam (RIB) facility. Project construction commenced in FY `93 with the initial emphasis placed on conversion of a heavily shielded room from an experiment area to an area suitable for housing the RIB injector. The RIB injector is the central component of the RIB project. The injector consists of two electrically connected high voltage platforms which are designed to operate at -300 kilovolts and which are separated bye a shield wall. One platform houses control, instrumentation, an power supplies. The second platform houses the first stage mass separator system which is designed for 1 part in 1000 mass resolution, electrostatic quadrupole lenses for beam transport, and a cesium charge cell for conversion of positive ions to negative ions for injection into the Tandem Accelerator. This paper details the design and beam development aspects of the RIB injector.

Dowling, D.T.; Alton, G.D.; Auble, R.L.; Dinehart, M.R.; Haynes, D.L.; Johnson, J.W.; Juras, R.C.; Kwon, Y.S.; Meigs, M.J.; Mills, C.D. [and others

1995-12-31

35

Evaluation of radioactive scrap metal recycling  

SciTech Connect

This report evaluates the human health risks and environmental and socio-political impacts of options for recycling radioactive scrap metal (RSM) or disposing of and replacing it. Argonne National Laboratory (ANL) is assisting the US Department of Energy (DOE), Office of Environmental Restoration and Waste Management, Oak Ridge Programs Division, in assessing the implications of RSM management alternatives. This study is intended to support the DOE contribution to a study of metal recycling being conducted by the Task Group on Recycling and Reuse of the Organization for Economic Cooperation and Development. The focus is on evaluating the justification for the practice of recycling RSM, and the case of iron and steel scrap is used as an example in assessing the impacts. To conduct the evaluation, a considerable set of data was compiled and developed. Much of this information is included in this document to provide a source book of information.

Nieves, L.A.; Chen, S.Y.; Kohout, E.J.; Nabelssi, B.; Tilbrook, R.W.; Wilson, S.E.

1995-12-01

36

Thermochemical Processing of Radioactive Waste Using Powder Metal Fuels  

SciTech Connect

Problematic radioactive wastes were generated during various activities of both industrial facilities and research institutions usually in relative small amounts. These can be spent ion exchange resins, inorganic absorbents, wastes from research nuclear reactors, irradiated graphite, mixed, organic or chlorine-containing radioactive waste, contaminated soils, un-burnable heavily surface-contaminated materials, etc. Conventional treatment methods encounter serious problems concerning processing efficiency of such waste, e.g. complete destruction of organic molecules and avoiding of possible emissions of radionuclides, heavy metals and chemically hazardous species. Some contaminations cannot be removed from surface using common decontamination methods. Conditioning of ash residues obtained after treatment of solid radioactive waste including ashes received from treating problematic wastes also is a complicated task. Moreover due to relative small volume of specific type radioactive waste the development of target treatment procedures and facilities to conduct technological processes and their deployment could be economically unexpedient and ecologically no justified. Thermochemical processing technologies are used for treating and conditioning problematic radioactive wastes. The thermochemical processing uses powdered metal fuels (PMF) that are specifically formulated for the waste composition and react chemically with the waste components. The composition of the PMF is designed in such a way as to minimize the release of hazardous components and radionuclides in the off gas and to confine the contaminants in the ash residue. The thermochemical procedures allow decomposition of organic matter and capturing hazardous radionuclides and chemical species simultaneously. A significant advantage of thermochemical processing is its autonomy. Thermochemical treatment technologies use the energy of exothermic reactions in the mixture of radioactive or hazardous waste with PMF. When used energy of exothermic reactions in waste thermochemical treatment processing, the problems concerned with heating method choice, appropriate heating equipment operation, and maintenance of this equipment reliability are excluded. Generally, the PMF consists of combustible powder metal, oxygen containing component, and some additives (pore-forming materials, stabilizers, surface-active substances, and other) with a predominance of metal powder. A thermodynamic simulation is applied widely at the designing of the PMF.

Ojovan, M. I.; Sobolev, I. A.; Dmitriev, S. A.; Panteleev, V. I.; Karlina, O. K.; Klimov. V. L.

2003-02-25

37

Selection and design of ion sources for use at the Holifield Radioactive Ion Beam Facility  

Microsoft Academic Search

The Holifield Radioactive Ion beam Facility now under construction at the Oak Ridge National Laboratory will use the 25-MV tandem accelerator for the acceleration of radioactive ion beams to energies appropriate for research in nuclear physics; negative ion beams are, therefore, required for injection into the tandem accelerator. Because charge exchange is an efficient means for converting initially positive ion

G. D. Alton; D. L. Haynes; G. D. Mills; D. K. Olsen

1993-01-01

38

Miniature high current metal ion source  

SciTech Connect

A small, simple ion source for the production of high brightness beams of metal ions is described. A metal vapor vacuum arc discharge is used to establish the high density plasma from which the ion beam is extracted. The source is finger-sized, and can produce pulsed metal ion beams with current up to the 10 ma range. 9 refs., 6 figs.

Brown, I.G.; Galvin, J.E.; MacGill, R.A.; Wright, R.T.

1986-04-01

39

Expansion of the radioactive ion beam program at Argonne  

Microsoft Academic Search

The Argonne Tandem Linear Accelerator System (ATLAS) at Argonne National Laboratory (ANL) provides a wide range of stable ion beams and radioactive beams which have contributed to our understanding of nuclear structure and reactions. Until now, most radioactive ion beams at ATLAS were produced in flight using light-ion reactions such as (p, n), (d, n), (d, p), (d,3He), and (3He,n).

J. A. Clark

2011-01-01

40

Status of JAEA–KEK radioactive ion beam facility, TRIAC  

Microsoft Academic Search

In collaboration with Japan Atomic Energy Agency (JAEA) and High Energy Accelerator Research Organization (KEK), we have been constructed an ISOL-based radioactive ion beam facility, Tokai Radioactive Ion Accelerator Complex (TRIAC), at JAEA – Tokai. This facility consists of a Charge-Breeding 18GHz Electron Cyclotron Resonance Ion-Source (CB-ECRIS), the Split-Coaxial Radio-Frequency Quadrupole (SCRFQ)- and Interdigital-H (IH)-type linacs. An Isotope Separator On-line

Akihiko Osa

2007-01-01

41

Titanate-based adsorbents for radioactive ions entrapment from water.  

PubMed

This feature article reviews some titanate-based adsorbents for the removal of radioactive wastes (cations and anions) from water. At the beginning, we discuss the development of the conventional ion-exchangeable titanate powders for the entrapment of radioactive cations, such as crystalline silicotitanate (CST), monosodium titanate (MST), peroxotitanate (PT). Then, we specially emphasize the recent progress in the uptake of radioactive ions by one-dimensional (1D) sodium titanate nanofibers and nanotubes, which includes the synthesis and phase transformation of the 1D nanomaterials, adsorption ability (capacity, selectivity, kinetics, etc.) of radioactive cations and anions, and the structural evolution during the adsorption process. PMID:23412572

Yang, Dongjiang; Liu, Hongwei; Zheng, Zhanfeng; Sarina, Sarina; Zhu, Huaiyong

2013-03-21

42

Titanate-based adsorbents for radioactive ions entrapment from water  

NASA Astrophysics Data System (ADS)

This feature article reviews some titanate-based adsorbents for the removal of radioactive wastes (cations and anions) from water. At the beginning, we discuss the development of the conventional ion-exchangeable titanate powders for the entrapment of radioactive cations, such as crystalline silicotitanate (CST), monosodium titanate (MST), peroxotitanate (PT). Then, we specially emphasize the recent progress in the uptake of radioactive ions by one-dimensional (1D) sodium titanate nanofibers and nanotubes, which includes the synthesis and phase transformation of the 1D nanomaterials, adsorption ability (capacity, selectivity, kinetics, etc.) of radioactive cations and anions, and the structural evolution during the adsorption process.

Yang, Dongjiang; Liu, Hongwei; Zheng, Zhanfeng; Sarina, Sarina; Zhu, Huaiyong

2013-02-01

43

Bunching and Cooling of Radioactive Ions with REXTRAP.  

National Technical Information Service (NTIS)

The properties of radioactive ion beams produced by the present on- line target ion source technology are often not suitable for direct post acceleration. For that purpose pulsed and cooled beams of higher charged ions are required. In the case of REX-ISO...

D. Beck D. Habs F. Amers G. Bollen O. Forstner

2002-01-01

44

Selection and design of ion sources for use at the Holifield radioactive ion beam facilitya)  

Microsoft Academic Search

The Holifield Radioactive Ion Beam Facility now under construction at the Oak Ridge National Laboratory will use the 25 MV tandem accelerator for the acceleration of radioactive ion beams to energies appropriate for research in nuclear physics; negative ion beams are, therefore, required for injection into the tandem accelerator. Because charge exchange is an efficient means for converting initially positive

G. D. Alton; D. L. Haynes; G. D. Mills; D. K. Olsen

1994-01-01

45

The production of accelerated radioactive ion beams  

SciTech Connect

During the last few years, substantial work has been done and interest developed in the scientific opportunities available with accelerated radioactive ion beams (RIBs) for nuclear physics, astrophysics, and applied research. This interest has led to the construction, development, and proposed development of both first- and second-generation RIB facilities in Asia, North America, and Europe; international conferences on RIBs at Berkeley and Louvain-la-Neuve; and many workshops on specific aspects of RIB production and science. This paper provides a discussion of both the projectile fragmentation, PF, and isotope separator on-line, ISOL, approach to RIB production with particular emphasis on the latter approach, which employs a postaccelerator and is most suitable for nuclear structure physics. The existing, under construction, and proposed facilities worldwide are discussed. The paper draws heavily from the CERN ISOLDE work, the North American IsoSpin Laboratory (ISL) study, and the operating first-generation RIB facility at Louvain-la-Neuve, and the first-generation RIB project currently being constructed at ORNL.

Olsen, D.K.

1993-11-01

46

Computational Design of Metal Ion Sequestering Agents.  

National Technical Information Service (NTIS)

Organic ligands that exhibit a high degree of metal ion recognition are essential precursors for developing separation processes and sensors for metal ions. Since the beginning of the nuclear era, much research has focused on discovering ligands that targ...

B. P. Hay B. M. Rapko R. T. Paine K. N. Raymond B. A. Moyer

2004-01-01

47

Rational Design of Metal Ion Sequestering Agents.  

National Technical Information Service (NTIS)

The discriminate bonding of metal ions is a challenge to the synthetic chemist and a phenomenon of considerable practical importance. An important feature of many technical applications is the specific or preferential binding of a single metal ion in the ...

K. N. Raymond

2004-01-01

48

Speciation of Metal Ions by Capillary Electrophoresis  

Microsoft Academic Search

The speciation of metal ions by capillary electrophoresis is an important area for environmental chemists. The speciation of metal ions by capillary electrophoresis in different matrices is reviewed. Various aspects of speciation such as sample pretreatment, metal ion complexation, detection, detection limit, choice of electrolytes, etc. have been described. Suggestions to improve the application of CE for the speciation of

Imran Ali; Hassan Y. Aboul-Enein

2002-01-01

49

Mechanistic Enzyme Models: Pyridoxal and Metal Ions.  

ERIC Educational Resources Information Center

Background information, procedures, and results are presented for experiments on the pyridoxal/metal ion model system. These experiments illustrate catalysis through Schiff's base formation between aldehydes/ketones and primary amines, catalysis by metal ions, and the predictable manner in which metal ions inhibit or catalyze reactions. (JN)

Hamilton, S. E.; And Others

1984-01-01

50

Status of JAEA KEK radioactive ion beam facility, TRIAC  

NASA Astrophysics Data System (ADS)

In collaboration with Japan Atomic Energy Agency (JAEA) and High Energy Accelerator Research Organization (KEK), we have been constructed an ISOL-based radioactive ion beam facility, Tokai Radioactive Ion Accelerator Complex (TRIAC), at JAEA Tokai. This facility consists of a Charge-Breeding 18 GHz Electron Cyclotron Resonance Ion-Source (CB-ECRIS), the Split-Coaxial Radio-Frequency Quadrupole (SCRFQ)- and Interdigital-H (IH)-type linacs. An Isotope Separator On-line (JAEA ISOL) is connected to the CB-ECRIS as the injector of radioactive ions which are produced in proton-induced fission of uranium and heavy-ion reaction. The primary beams are provided from the JAEA Tandem Accelerator. Radioactive singly-charged ions from the JAEA ISOL are bred to q/A ? 1/7 in the CB-ECRIS and then multi-charged ions are accelerated with the linac-complex from 2 keV/u to the energy between 0.14 and 1.1 MeV/u. So far, we successfully accelerate 8Li+ and 138Xe20+, the acceleration energy of 1.1 MeV/u was achieved. From October 2005, some radioactive ion beams of 1.1 MeV/u have become available for users.

TRIAC Collaboration

2007-08-01

51

Tokai Radioactive Ion Accelerator Complex (TRIAC): present and future  

SciTech Connect

Tokai Radioactive Ion Accelerator Complex (TRIAC) is the low-energy accelerator complex for re-accelerating short-lived radioactive ion beams (RIBs) in Japan. After the introduction of the present status of the TRIAC, considered as future extension of the present TRIAC activity, we are going to discuss our experimental proposal to investigate the beta-decay properties of neutron-rich rare isotopes involved in the 3{sup rd} peak in the r-process element abundance.

Jeong, S. C. [Tokai Campus, High Energy Accelerator Research Organization (KEK), Shirakata Shirane 2-4, Tokai, Ibaraki 319-1195 (Japan)

2010-04-30

52

Rational Design of Metal Ion Sequestering Agents  

SciTech Connect

The discriminate bonding of metal ions is a challenge to the synthetic chemist and a phenomenon of considerable practical importance.1 An important feature of many technical applications is the specific or preferential binding of a single metal ion in the presence of many metals. Examples range from large-volume uses (e.g. ferric EDTA as a plant food, calcium complexing agents as water softeners or anticaking formulations) to very high technology applications (technetium complexation in radiopharmaceuticals, synthetic metalloenzymes). We are interested in efficient and discriminate binding of actinides for waste stream remediation. Actinides represent a major and long-lived contaminant in nuclear waste. While the separation of actinides from other radioactive components of waste, such as Sr and Cs, is relatively well established, the separation of actinides from each other and in complex solutions (e.g. those found in tank wastes) is not as well resolved. The challenge of designing metal-specific (actinide) ligands is facilitated by examples from nature. Bacteria synthesize Fe(III)-specific ligands, called siderophores, to sequester Fe(III) from the environment and return it to the cell. The similarities between Fe(III) and Pu(IV) (their charge-to-size ratios and acidity), make the siderophores prototypical for designing actinide-specific ligands. The chelating groups present in siderophores are usually hydroxamic acids and catecholamides. We have developed derivatives of these natural products which have improved properties. The catechol derivatives are the 2,3-dihydroxyterephthalamides (TAMs), and 3,4-dihydroxysulfonamides (SFAMs), and the hydroxamic acid derivatives are three isomers of hydroxypyridinones, 1,2- HOPO, 3,2-HOPO, and 3,4-HOPO. All of these ligands are attached to molecular backbones by amides and a very important feature of HOPO and CAM ligands is a strong hydrogen bonds formed between the amide proton and the adjacent phenolic oxygen in the metal complex, thereby enhancing the stability (Figure 1).

Raymond, Kenneth N.

2000-09-30

53

RIBLL, the radioactive ion beam line in Lanzhou  

Microsoft Academic Search

A fragment separator, the Radioactive Ion Beam Line in Lanzhou, has been constructed at the Heavy Ion Research Facility of Lanzhou and in operation since January 1998. In this paper, the features of the structure and performance are described in detail. Some early stage results are presented also.

Z. Sun; W.-L. Zhan; Z.-Y. Guo; G. Xiao; J.-X. Li

2003-01-01

54

Method for permanently storing radioactive ion exchanger resins  

Microsoft Academic Search

A method is claimed for forming a hardened product containing a radioactive ion exchanger resin in a condition for permanent, noncontaminating storage, by the steps of: providing, before fixing, a mass of such ion exchanger resin saturated in water, the resin being at least one resin selected from the group consisting of spherical resins and powdered resins; mixing the resin

S. Kunze; G. Eden; R. Koster

1984-01-01

55

Fixation of radioactive ions in porous media with ion exchange gels  

DOEpatents

A method is provided for fixing radioactive ions in porous media by injecting into the porous media water-soluble organic monomers which are polymerizable to gel structures with ion exchange sites and polymerizing the monomers to form ion exchange gels. The ions and the particles of the porous media are thereby physically fixed in place by the gel structure and, in addition, the ions are chemically fixed by the ion exchange properties of the resulting gel.

Mercer, Jr., Basil W. (Pasco, WA); Godfrey, Wesley L. (Aiken, SC)

1979-01-01

56

EBIS charge breeder for radioactive ion beams at ATLAS.  

SciTech Connect

The construction of the Californium Rare Isotope Breeder Upgrade (CARIBU) for the Argonne National Laboratory ATLAS facility is completed and its commissioning is being performed. In its full capacity, the CARIBU facility will use fission fragments from a 1 Curie (Ci) {sup 252}Cf source. The ions will be thermalized and collected into a low-energy ion beam by a helium gas catcher, mass analyzed by an isobar separator, and charge bred to higher charge states for acceleration in ATLAS. To reach energies E/A 10 MeV/u, one should inject ions with charge-to-mass ratio (q/A) {ge} 1/7 into the ATLAS linac. In the first stage, the existing Electron Cyclotron Resonance (ECR) ion source will be used as a charge breeder. The maximum intensity of radioactive ion beams at the output of the gas catcher will not exceed 10{sup 7} ions per second. A charge breeder based on an Electron Beam Ion Source (EBIS) has significant advantages over the ECR option for ion beam intensities up to about 10{sup 9} ions per second, providing 3-4 times higher efficiency and significantly better purity of highly charged radioactive ion beams for further acceleration. The proposed EBIS project for CARIBU will heavily utilize state-of-the-art EBIS technology recently developed at Brookhaven National Laboratory. This will allow us to reduce both the project cost and timescale, simultaneously insuring reliable technical realization of the cutting-edge technology. Several parameters of the CARIBU EBIS charge breeder (EBIS-CB) will be relaxed with respect to the BNL EBIS in favor of higher reliability and lower cost. Technical performance of the CARIBU charge breeder will not suffer from such a relaxation and will provide high efficiency for a whole range of radioactive ion beams. The goal of this paper is to present the initial design of the EBIS charge breeder for radioactive ion beams at ATLAS.

Ostroumov, P.; Kondrashev, S.; Pardo, R.; Savard, G.; Vondrasek, R.; Alessi, J.; Beebe, E.; Pikin, A. (Physics); (BNL)

2010-07-01

57

EBIS charge breeder for radioactive ion beams at ATLAS  

SciTech Connect

The construction of the Californium Rare Isotope Breeder Upgrade (CARIBU) for the Argonne National Laboratory ATLAS facility is completed and its commissioning is being performed. In its full capacity, the CARIBU facility will use fission fragments from a 1 Curie (Ci) {sup 252}Cf source. The ions will be thermalized and collected into a low-energy ion beam by a helium gas catcher, mass analyzed by an isobar separator, and charge bred to higher charge states for acceleration in ATLAS. To reach energies E/A 10 MeV/u, one should inject ions with charge-to-mass ratio (q/A) {ge} 1/7 into the ATLAS linac. In the first stage, the existing Electron Cyclotron Resonance (ECR) ion source will be used as a charge breeder. The maximum intensity of radioactive ion beams at the output of the gas catcher will not exceed 10{sup 7} ions per second. A charge breeder based on an Electron Beam Ion Source (EBIS) has significant advantages over the ECR option for ion beam intensities up to about 10{sup 9} ions per second, providing 3-4 times higher efficiency and significantly better purity of highly charged radioactive ion beams for further acceleration. The proposed EBIS project for CARIBU will heavily utilize state-of-the-art EBIS technology recently developed at Brookhaven National Laboratory. This will allow us to reduce both the project cost and timescale, simultaneously insuring reliable technical realization of the cutting-edge technology. Several parameters of the CARIBU EBIS charge breeder (EBIS-CB) will be relaxed with respect to the BNL EBIS in favor of higher reliability and lower cost. Technical performance of the CARIBU charge breeder will not suffer from such a relaxation and will provide high efficiency for a whole range of radioactive ion beams. The goal of this paper is to present the initial design of the EBIS charge breeder for radioactive ion beams at ATLAS.

Ostroumov, P.; Alessi, J.; Kondrashev, S.; Pardo, R.; Savard, G.; Vondrasek, R.; Beebe, E.; Pikin, A.

2010-07-20

58

Engineered Biofilms for Metal Ion Removal  

Microsoft Academic Search

Firstly, biofilm and biosorbents are defined. Mechanisms of interactions between metal ions and biofilm are discussed in terms of diffusion, mass transfer and sorption. In a second step, different processes using biofilm to remove heavy metal in aqueous solutions are presented. The continuously stirred processes are described for metal ion removal in wastewater by biofilm coating particles. In this case,

P. Le Cloirec; Y. Andrè; C. Faur-Brasquet; C. Gérente

2003-01-01

59

Status report of stable and radioactive ion beam production at GANIL  

SciTech Connect

GANIL has been producing many stable and radioactive ion beams for nearly 25 years. Constant progresses have been made in terms of intensity, stability, and reliability. The intensity for some stable metallic beams now exceeds or approaches the p {mu}A level at an energy up to 95 MeV/u, e.g., 1.14 p {mu}A for {sup 36}S (65% enriched) at 77 MeV/u, 0.35 p {mu}A for {sup 58}Ni (63% enriched) at 74 MeV/u. Some recent results with Magnesocene using the metallic ions from volatile compounds method should also make possible the production of metallic beams with an intensity greater than 1 p {mu}A. This has still to be measured. The ISOL facility SPIRAL I has been in operation for almost six years. Up to now, 17 exotic He experiments have been done with 14 target/ion-source (TIS) units; 19 other experiments (with O, Ne, Ar, and Kr) have been achieved with 14 TISs. Statistics show a fairly good ratio of available beam time to scheduled beam time. The radioactive beams and available intensities are compiled in this report. Future developments on radioactive ion beam production are briefly presented, while more details will be discussed elsewhere at this conference.

Gaubert, G.; Barue, C.; Canet, C.; Cornell, J. C.; Dubois, M.; Dupuis, M.; Eleon, C.; Flambard, J. L.; Frigot, R.; Jardin, P.; Leboucher, C.; Lecesne, N.; Leherissier, P.; Lemagnen, F.; Leroy, R.; Pacquet, J. Y. [GANIL - Grand Accelerateur National d'Ions Lourds, Bvd Henry Becquerel, BP 55027, 14076 Caen Cedex 5 (France)

2008-02-15

60

Charge breeding simulations for radioactive ion beam production  

SciTech Connect

The charge breeding technique is used for radioactive ion beam (RIB) production in order of optimizing the re-acceleration of the radioactive element ions produced by a primary beam in a thick target. Charge breeding is achieved by means of a device capable of increasing the ion charge state from 1+ to a desired value n+. In order to get high intensity RIB, experiments with charge breeding of very high efficiency could be required. To reach this goal, the charge breeding simulation could help to optimize the high charge state production efficiency by finding more proper parameters for the radioactive 1+ ions. In this paper a device based on an electron beam ion source (EBIS) is considered. In order to study that problem, a code already developed for studying the ion selective containment in an EBIS with RF quadrupoles, BRICTEST, has been modified to simulate the ion charge state breeding rate for different 1+ ion injection conditions. Particularly, the charge breeding simulations for an EBIS with a hollow electron beam have been studied.

Variale, V. [INFN-Bari, Via Orabona, 4, Bari (Italy); Raino, A. C.; Clauser, T. [Physics Department of Bari University and INFN- Bari, Via Orabona, 4, Bari (Italy)

2012-02-15

61

Charge breeding simulations for radioactive ion beam production  

NASA Astrophysics Data System (ADS)

The charge breeding technique is used for radioactive ion beam (RIB) production in order of optimizing the re-acceleration of the radioactive element ions produced by a primary beam in a thick target. Charge breeding is achieved by means of a device capable of increasing the ion charge state from 1+ to a desired value n+. In order to get high intensity RIB, experiments with charge breeding of very high efficiency could be required. To reach this goal, the charge breeding simulation could help to optimize the high charge state production efficiency by finding more proper parameters for the radioactive 1+ ions. In this paper a device based on an electron beam ion source (EBIS) is considered. In order to study that problem, a code already developed for studying the ion selective containment in an EBIS with RF quadrupoles, BRICTEST, has been modified to simulate the ion charge state breeding rate for different 1+ ion injection conditions. Particularly, the charge breeding simulations for an EBIS with a hollow electron beam have been studied.

Variale, V.; Rainò, A. C.; Clauser, T.

2012-02-01

62

Physics with energetic radioactive ion beams  

SciTech Connect

Beams of short-lived, unstable nuclei have opened new dimensions in studies of nuclear structure and reactions. Such beams also provide key information on reactions that take place in our sun and other stars. Status and prospects of the physics with energetic radioactive beams are summarized.

Henning, W.F.

1996-12-31

63

Liquid metal ion source and alloy  

DOEpatents

A liquid metal ion source and alloy, wherein the species to be emitted from the ion source is contained in a congruently vaporizing alloy. In one embodiment, the liquid metal ion source acts as a source of arsenic, and in a source alloy the arsenic is combined with palladium, preferably in a liquid alloy having a range of compositions from about 24 to about 33 atomic percent arsenic. Such an alloy may be readily prepared by a combustion synthesis technique. Liquid metal ion sources thus prepared produce arsenic ions for implantation, have long lifetimes, and are highly stable in operation.

Clark, Jr., William M. (Thousand Oaks, CA); Utlaut, Mark W. (Saugus, CA); Behrens, Robert G. (Los Alamos, NM); Szklarz, Eugene G. (Los Alamos, NM); Storms, Edmund K. (Los Alamos, NM); Santandrea, Robert P. (Santa Fe, NM); Swanson, Lynwood W. (McMinnville, OR)

1988-10-04

64

MEVVA ion source for high current metal ion implantation  

Microsoft Academic Search

The MEVVA (Metal Vapor Vacuum Arc) ion source is a new kind of source which can produce high current beams of metal ions. Beams of a wide range of elements have been produced, spanning the periodic table from lithium up to and including uranium. The source extraction voltage is up to 60 kV, and we are increasing this up to

I. Brown; J. Washburn

1986-01-01

65

Low specificity of metal ion binding in the metal ion core of a folded RNA  

Microsoft Academic Search

The structure and activity of nucleic acids depend on their interactions with metal ions. Fundamental to these interactions is the degree of specificity observed between the metal ions and nucleic acids, and a complete description of nucleic acid folding requires that we understand the nature of the interactions with metal ions, including specificity. The prior demonstration that high concentrations of

KEVIN J. TRAVERS; NATHAN BOYD; DANIEL HERSCHLAG

2007-01-01

66

Nuclear astrophysics at the Holifield Radioactive Ion Beam Facility  

SciTech Connect

Reactions involving radioactive nuclei play an important role in explosive stellar events such as novae, supernovae, and X-ray bursts. The development of accelerated, proton-rich radioactive ion beams provides a tool for directly studying many of the reactions that fuel explosive hydrogen burning. The experimental nuclear astrophysics program at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory is centered on absolute cross section measurements of these reactions with radioactive ion beams. Beams of {sup 17}F and {sup 18}F, important nuclei in the hot-CNO cycle, are currently under development at HRIBF. Progress in the production of intense radioactive fluorine beams is reported. The Daresbury Recoil Separator (DRS) has been installed at HRIBF as the primary experimental station for nuclear astrophysics experiments. The DRS will be used to measure reactions in inverse kinematics with the techniques of direct recoil detection, delayed-activity recoil detection, and recoil-gamma coincidence measurements. The first astrophysics experiments to be performed at HRIBF, mA the application of the recoil separator in these measurements, are discussed.

Blackmon, J.C. [Oak Ridge National Lab., TN (United States)][North Carolina Univ., Chapel Hill, NC (United States)

1996-10-01

67

?-delayed neutron spectroscopy using trapped radioactive ions.  

PubMed

A novel technique for ?-delayed neutron spectroscopy has been demonstrated using trapped ions. The neutron-energy spectrum is reconstructed by measuring the time of flight of the nuclear recoil following neutron emission, thereby avoiding all the challenges associated with neutron detection, such as backgrounds from scattered neutrons and ? rays and complicated detector-response functions. (137)I(+) ions delivered from a (252)Cf source were confined in a linear Paul trap surrounded by radiation detectors, and the ?-delayed neutron-energy spectrum and branching ratio were determined by detecting the ?(-) and recoil ions in coincidence. Systematic effects were explored by determining the branching ratio three ways. Improvements to achieve higher detection efficiency, better energy resolution, and a lower neutron-energy threshold are proposed. PMID:23496704

Yee, R M; Scielzo, N D; Bertone, P F; Buchinger, F; Caldwell, S; Clark, J A; Deibel, C M; Fallis, J; Greene, J P; Gulick, S; Lascar, D; Levand, A F; Li, G; Norman, E B; Pedretti, M; Savard, G; Segel, R E; Sharma, K S; Sternberg, M G; Van Schelt, J; Zabransky, B J

2013-02-26

68

?-Delayed Neutron Spectroscopy Using Trapped Radioactive Ions  

NASA Astrophysics Data System (ADS)

A novel technique for ?-delayed neutron spectroscopy has been demonstrated using trapped ions. The neutron-energy spectrum is reconstructed by measuring the time of flight of the nuclear recoil following neutron emission, thereby avoiding all the challenges associated with neutron detection, such as backgrounds from scattered neutrons and ? rays and complicated detector-response functions. I+137 ions delivered from a Cf252 source were confined in a linear Paul trap surrounded by radiation detectors, and the ?-delayed neutron-energy spectrum and branching ratio were determined by detecting the ?- and recoil ions in coincidence. Systematic effects were explored by determining the branching ratio three ways. Improvements to achieve higher detection efficiency, better energy resolution, and a lower neutron-energy threshold are proposed.

Yee, R. M.; Scielzo, N. D.; Bertone, P. F.; Buchinger, F.; Caldwell, S.; Clark, J. A.; Deibel, C. M.; Fallis, J.; Greene, J. P.; Gulick, S.; Lascar, D.; Levand, A. F.; Li, G.; Norman, E. B.; Pedretti, M.; Savard, G.; Segel, R. E.; Sharma, K. S.; Sternberg, M. G.; Van Schelt, J.; Zabransky, B. J.

2013-03-01

69

Status report for the Holifield Radioactive Ion Beam Facility  

SciTech Connect

In 1992, the HHIRF became a project to develop a first-generation radioactive ion beam facility, the HRIBF, a national user facility for RIB research. Intense beams from ORIC will produce radioactive atoms as reaction products in thick targets using an ISOL-type target-ion source mounted on a 300-kV RIB injector. These radioactive atoms will be ionized, mass analyzed, charge exchanged, accelerated to ground potential, and analyzed again to separate isobars with a second-stage mass analyzer. The resulting RIBs will be injected into the tandem and accelerated to energies of interest for nuclear physics and astrophysics studied. The construction phase of the project has been completed. A report on the status and progress developing the facility is given, along with the long term development plans.

Olsen, D.K.; Auble, R.L.; Alton, G.D. [and others

1995-12-31

70

Development of an RF Ion Guide for Trapping Energetic Radioactive Nuclear Ions.  

National Technical Information Service (NTIS)

Although the projectile fragment separator (RIPS) at the RIKEN accelerator facility (RARF) provides wide variety of energetic radioactive beams, it is not adequate for low energy beam experiments such as precision spectroscopy of trapped ions. Aiming for ...

M. Wada N. Oshima T. Nakamura Y. Ishida Y. Nakai

2002-01-01

71

Contamination analysis of radioactive samples in focused ion beam instruments.  

PubMed

The use of Focused Ion Beam (FIB) instrument's to analyze and prepare samples that are radioactive requires attentiveness to the materials that are dislodged and free inside the chamber. Radioactive sputtered material must be understood even when observed at trace concentrations. Measurements using liquid scintillation counting and high purity germanium detectors were used to evaluate contamination on accessible surfaces inside a focused ion beam chamber that was used in the preparation of samples that were radioactive. The maximum removable contamination found was 0.27 0.4 Bq cm(-2), on the focused ion beam wall with 0.24 0.019 Bq cm(-2) on the door. Although these magnitudes of removable contamination are inconsequential for activation products, these same magnitudes of actinides, for example 239Pu, would represent 3.2% of an Annual Limit of Intake. This might be considered significant if one examines the relatively infrequent use of this device for the preparation of radioactive samples. Predicted activities of sputtered material were found using the software Transport of Ions in Matter, estimating that 0.003% of a radioactive samples activity is released into the FIB chamber. A used secondary electron detector's activity was measured to be 383.7 8.1 Bq. Preferential build-up of sputtered materials due to temperature or static charge gradients was considered. No temperature gradients were observed. Static charge gradients were measured inside the chamber varying between 0.057% below the mean to 34% higher than the mean. However, the magnitudes of contamination measured did not correlate to static charge gradients. Deposition in the chamber appears to have no mechanical cause but rather is sporadic however, measureable. Experience to date has been limited to samples of low activity; nevertheless, contamination inside the chamber was observed. Users should anticipate higher levels of readily dispersible radioactive contamination within the FIB as sample activity increases. PMID:23287516

Evelan, Audrey Ruth; Brey, Richard R

2013-02-01

72

ISOLATION OF RADIOACTIVE METALS FROM LIQUID WASTES  

EPA Science Inventory

Metals are present in many waste streams, and pose challenges with regard to their disposal. Release of metals into the environment presents both human health and ecological concerns. As a result, efforts are directed at reducing their toxicity, bioavailability, and environment...

73

Separation of metal ions from aqueous solutions  

DOEpatents

A process and apparatus for quantitatively and selectively separating metal ions from mixtures thereof in aqueous solution. The apparatus includes, in combination, a horizontal electrochemical flow cell containing flow bulk electrolyte solution and an aqueous, metal ion-containing solution, the cell containing a metal mesh working electrode, a counter electrode positioned downstream from the working electrode, an independent variable power supply/potentiostat positioned outside of the flow cell and connected to the electrodes, and optionally a detector such as a chromatographic detector, positioned outside the flow cell. This apparatus and its operation has significant application where trace amounts of metal ions are to be separated.

Almon, Amy C. (Augusta, GA)

1994-01-01

74

Separation of metal ions from aqueous solutions  

DOEpatents

This invention is comprised of a process and apparatus for quantitatively and selectively separating metal ions from mixtures thereof in aqueous solution. The apparatus includes, in combination, a horizontal electrochemical flowing cell containing flowing bulk electrolyte solution and an aqueous, metal ion-containing solution, the cell containing a metal mesh working electrode, a counter electrode positioned downstream from the working electrode, an independent variable power supply/potentiostat positioned outside of the flowing cell and connected to the electrodes, and optionally a detector such as a chromatographic detector, positioned outside the flowing cell. This apparatus and its operation has significant application where trace amounts of metal ions are to be separated.

Almon, A.

1991-12-31

75

Expansion of the radioactive ion beam program at Argonne  

NASA Astrophysics Data System (ADS)

The Argonne Tandem Linear Accelerator System (ATLAS) at Argonne National Laboratory (ANL) provides a wide range of stable ion beams and radioactive beams which have contributed to our understanding of nuclear structure and reactions. Until now, most radioactive ion beams at ATLAS were produced in flight using light-ion reactions such as (p, n), (d, n), (d, p), (d,3He), and (3He,n). Within the next few months, the radioactive ion beam program at ATLAS will acquire much extended, new capabilities with the commissioning of a new facility: the CAlifornium Rare Isotope Breeder Upgrade (CARIBU). CARIBU will supply ion beams of 252Cf fission fragments, which are thermalized in a gas catcher. The singly- and doubly-charged ions extracted from the gas catcher will be mass-separated and either delivered to a low-energy experimental area, or charge bred with a modified ECR source and subsequently reaccelerated by the ATLAS facility. Properties of hundreds of these neutron-rich nuclides will be investigated using ion traps, decay stations, the newly commissioned HELical Orbit Spectrometer (HELIOS), and other available experimental equipment such as Gammasphere and the FMA. HELIOS was constructed to take advantage of rare ion beams, such as those provided by CARIBU, through light-ion transfer reactions in inverse kinematics, and represents a new approach to the study of direct reactions in inverse kinematics which avoids kinematic broadening. Experiments are currently being conducted with HELIOS, and first results with the d(28Si,p) and d(12B,p) reactions have shown excellent energy resolution.

Clark, J. A.

2011-01-01

76

Uptake of Metal Ions on Humic Acids  

Microsoft Academic Search

The kinetics, the sorption capacities, pH and temperature dependence of sorption of humic acids (HAs) of Turkish brown coals with respect to Zn(II), Cu(II), Ni(II), Co(II) and Pb(II) ions were investigated, and the roles of the carboxylic and phenolic groups in the adsorption of metals ion on HAs were searched in this work. These metal ions are able to form

E. Pehlivan; G. Arslan

2006-01-01

77

Rational Design of Metal Ion Sequestering Agents  

Microsoft Academic Search

The discriminate bonding of metal ions is a challenge to the synthetic chemist and a phenomenon of considerable practical importance.1 An important feature of many technical applications is the specific or preferential binding of a single metal ion in the presence of many metals. Examples range from large-volume uses (e.g. ferric EDTA as a plant food, calcium complexing agents as

Kenneth N

2000-01-01

78

Selection and design of ion sources for use at the Holifield Radioactive Ion Beam Facility (abstract)a)  

Microsoft Academic Search

The Holifield Radioactive Ion Beam Facility now under construction at the Oak Ridge National Laboratory will use the 25-MV tandem accelerator for the acceleration of radioactive ion beams to energies appropriate for research in nuclear physics; negative ion beams are, therefore, required for injection into the tandem accelerator. Because charge exchange is an efficient means for converting initially positive ion

G. D. Alton; D. L. Haynes; G. D. Mills; D. K. Olsen

1994-01-01

79

The Scientific program with RIBRAS (Radioactive Ion Beams in Brasil)  

NASA Astrophysics Data System (ADS)

The Radioactive Ion Beams Facility (RIBRAS) is in operation since 2004 at the Pelletron Accelerator Laboratory of the University of Sa~o Paulo and consists of two superconducting solenoids capable of producing low energy secondary beams of light exotic nuclei. Measurements of the elastic scattering, breakup and transfer reactions with radioactive projectiles such as 6He, 8Li, 7Be on several targets have been performed. A review of the research program carried on along the last four years using the RIBRAS facility is presented.

Lichtenthäler, R.; Lépine-Szily, A.; Guimara~Es, V.; de Faria, P. N.; Mendes, D. R.; Otani, Y.; Leistenschneider, E.; Scarduelli, V.

2009-06-01

80

The Scientific program with RIBRAS (Radioactive Ion Beams in Brasil)  

SciTech Connect

The Radioactive Ion Beams Facility (RIBRAS) is in operation since 2004 at the Pelletron Accelerator Laboratory of the University of Sao Paulo and consists of two superconducting solenoids capable of producing low energy secondary beams of light exotic nuclei. Measurements of the elastic scattering, breakup and transfer reactions with radioactive projectiles such as {sup 6}He,{sup 8}Li,{sup 7}Be on several targets have been performed. A review of the research program carried on along the last four years using the RIBRAS facility is presented.

Lichtenthaeler, R.; Lepine-Szily, A.; Guimaraes, V.; Faria, P. N. de; Mendes, D. R. Jr.; Pires, K. C. C.; Morcelle, V.; Hussein, M. S.; Barioni, A.; Condori, R. Pampa; Morais, M. C.; Alcantara Nunez, J.; Camargo, O. Jr.; Otani, Y.; Leistenschneider, E.; Scarduelli, V. [Instituto de Fisica da Universidade de Sao Paulo, C.P. 66318, 05389-970 Sao Paulo (Brazil); Benjamim, E. A. [Universidad de Santiago de Compostela, Depto. Fisica Particulas, Facultad Fisica, Campus Sur s/n 15786 Santiago de Compostela (Spain) (Spain); Moro, A. M. [Departamento de FAMN, Universidad de Sevilla, Apdo 1065, E-41080, Sevilla (Spain); Arazi, A. [Laboratorio Tandar, Departamento de Fisica, Comision Nacional de Energia Atomica, Av. del Libertador 8250, (1429), Buenos Aires (Argentina); Assuncao, M. [UNIFESP-Campus de Diadema, SP (Brazil)] (and others)

2009-06-03

81

Selection and design of ion sources for use at the Holifield Radioactive Ion Beam Facility  

SciTech Connect

The Holifield Radioactive Ion beam Facility now under construction at the Oak Ridge National Laboratory will use the 25-MV tandem accelerator for the acceleration of radioactive ion beams to energies appropriate for research in nuclear physics; negative ion beams are, therefore, required for injection into the tandem accelerator. Because charge exchange is an efficient means for converting initially positive ion beams to negative ion beams, both positive and negative ion sources are viable options for use at the facility. The choice of the type of ion source will depend on the overall efficiency for generating the radioactive species of interest. Although direct-extraction negative ion sources are clearly desirable, the ion formation efficiencies are often too low for practical consideration; for this situation, positive ion sources, in combination with charge exchange, are the logical choice. The high-temperature version of the CERN-ISOLDE positive ion source has been selected and a modified version of the source designed and fabricated for initial use at the facility because of its low emittance, relatively high ionization efficiencies and species versatility, and because it has been engineered for remote installation, removal and servicing as required for safe handling in a high-radiation-level ISOL facility. The source will be primarily used to generate ion beams from elements with intermediate to low electron affinities. Prototype plasma-sputter negative ion sources and negative surface-ionization sources are under design consideration for generating radioactive ion beams from high-electron-affinity elements. The design features of these sources and expected efficiencies and beam qualities (emittances) will be described in this report.

Alton, G.D.; Haynes, D.L.; Mills, G.D.; Olsen, D.K.

1993-12-31

82

Heavy metals, organics and radioactivity in soil of western Serbia  

Microsoft Academic Search

Western Serbia is a region well-known for potato production. Concentrations of selected metals, polycyclic aromatic hydrocarbons (PAHs) and radioactivity were measured in the soil in order to evaluate the quality and characteristics. The examined soils (Luvisol and Pseudogley) showed unsuitable agrochemical characteristics (acid reaction, low content of organic matter and potassium). Some samples contained Ni, Mn and Cr above the

Goran Dugalic; Dragana Krstic; Miodrag Jelic; Dragoslav Nikezic; Biljana Milenkovic; Mira Pucarevic; Tijana Zeremski-Skoric

2010-01-01

83

Metal ion ligands in hyperaccumulating plants  

Microsoft Academic Search

Metal-hyperaccumulating plants have the ability to take up extraordinary quantities of certain metal ions without succumbing\\u000a to toxic effects. Most hyperaccumulators select for particular metals but the mechanisms of selection are not understood at\\u000a the molecular level. While there are many metal-binding biomolecules, this review focuses only on ligands that have been reported\\u000a to play a role in sequestering, transporting

Damien L. Callahan; Alan J. M. Baker; Spas D. Kolev; Anthony G. Wedd

2006-01-01

84

Immobilized calcein for metal ion preconcentration  

SciTech Connect

A technique is demonstrated for the preparation of immobilized calcein, (2',7',((bis(carboxymethyl)amino)methyl)-fluorescein), to be used for metal ion preconcentration. The calcein is of particular interest as a reagent for transition metals. The preconcentration is demonstrated for cobalt, copper, and nickel ions. Fluorescence spectra of the calcein at various pH values were obtained. Values were determined for the conditional binding constants of immobilized and dissolved calcein with the transition metal ions as a function of pH.

Not Available

1984-04-01

85

Moessbauer Effect applications using intense radioactive ion beams  

SciTech Connect

The Moessbauer Effect is reviewed as a promising tool for a number of new solid state studies when used in combination with radioactive beam/implantation facilities. The usual Moessbauer Effect involves long-lived radioactive parents (days to years) that populate low-lying nuclear excited states that subsequently decay to the ground state. Resonant emission/absorption of recoil-free gamma rays from these states provide information on a number of properties of the host materials. Radioactive ion beams (RIB) produced on-line allow new Moessbauer nuclei to be studied where there is no suitable parent. The technique allows useful sources to be made having extremely low local concentrations. The ability to separate the beams in both Z and A should provide high specific activity conventional'' sources, a feature important in some applications such as Moessbauer studies in diamond anvil high pressure cells. Exotic chemistry is proposed using RIB and certain Krypton and Xenon Moessbauer isotopes.

Taylor, R.D.

1990-01-01

86

Reducing metal ion release following hip resurfacing arthroplasty.  

PubMed

Recent guidelines have suggested that routine postoperative care of patients with metal-on-metal hip prostheses should involve metal ion analysis. This study sought to investigate the relationship between bearing surface wear rates of metal components and serum metal ion analysis and also to quantify the incidence of excessive increases in serum metal ion concentrations post-hip resurfacing arthroplasty. PMID:21435493

Langton, David J; Joyce, Thomas J; Mangat, Navjeet; Lord, James; Van Orsouw, Maarten; De Smet, Koen; Nargol, Antoni V F

2011-04-01

87

Purification of Radioactive Ion Beams by Photodetachment in a RF Quadrupole Ion Beam Cooler  

SciTech Connect

A highly efficient method for suppressing isobar contaminants in negative radioactive ion beams by photodetachment is demonstrated. A laser beam having the appropriate photon energy is used to selectively neutralize the contaminants. The efficiency of photodetachment can be substantially improved when the laser-ion interaction takes place inside a radio frequency quadrupole ion cooler. In off-line experiments with ion beams of stable isotopes, more than 99.9% suppression of Co{sup -}, S{sup -}, and O{sup -} ions has been demonstrated while under the identical conditions only 22% reduction in Ni{sup -} and no reduction in Cl{sup -} and F{sup -} ions were observed. This technique is being developed for on-line purification of a number of interesting radioactive beams, such as {sup 56}Ni, {sup 17,18}F, and {sup 33,36}Cl.

Liu, Y.; Havener, C. C.; Beene, J. R. [Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Lewis, T. L. [Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996 (United States); Galindo-Uribarri, A. [Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996 (United States)

2009-03-12

88

Purification of Radioactive Ion Beams by Photodetachment in a RF Quadrupole Ion Beam Cooler  

SciTech Connect

A highly efficient method for suppressing isobar contaminants in negative radioactive ion beams by photodetachment is demonstrated. A laser beam having the appropriate photon energy is used to selectively neutralize the contaminants. The efficiency of photodetachment can be substantially improved when the laser-ion interaction takes place inside a radio frequency quadrupole ion cooler. In off-line experiments with ion beams of stable isotopes, more than 99.9% suppression of Co{sup -}, S{sup -}, and O{sup -} ions has been demonstrated while under the identical conditions only 22% reduction in Ni{sup -} and no reduction in Cl{sup -} and F{sup -} ions were observed. This technique is being developed for on-line purification of a number of interesting radioactive beams, such as {sup 56}Ni, {sup 17,18}F, and {sup 33,36}Cl.

Liu, Yuan [ORNL; Beene, James R [ORNL; Havener, Charles C [ORNL; Galindo-Uribarri, Alfredo {nmn} [ORNL; Lewis, Thomas L. [University of Tennessee, Knoxville (UTK)

2009-01-01

89

Recovery of metal ions by microfungal filters.  

PubMed

Many microfungi contain chitin/chitosan as an integral part of the cell wall structure. The binding of toxic and heavy metal ions by chitosan or partly deacetylated chitin is a direct consequence of the base strength of the primary amine group and is most effective for those metals that form complexes with ammonia. Of the microfungi studied, hyphae from Mucor mucedo and Rhizomucor miehei, after treatment with hydroxide to expose the chitin/chitosan, were found to be most effective in the capture of metal ions. Chemically treated mycelia have so far been shown to bind silver, zinc, lead, copper, nickel, cobalt, cadmium, iron and chromium, with the efficiency of metal-ion binding apparently being inversely proportional to the valency state of the metal ions to be bound. Wet-laid papers produced from mixed slurries of treated mycelia and various conventional paper-making and textile fibres have exceptionally good tensile- and bursting-strength properties, particularly in the wet state. Papers containing 1 g treated mycelia removed up to 90% of various metal ions in solution (50 cm3, 1.5 mmol dm-3) with flow rates of 0.5 cm3 cm-2 min-1. However, the total metal-ion binding capacities of single-thickness microfungal papers are limited under constant flow conditions. The total volume flowing through the system before metal-ion breakthrough occurs increases in direct proportion to the number of sheets of microfungal paper but the concomitant reduction in flow rates becomes a limiting factor. Mycelia-containing structures that allow efficient metal-ion binding at commercially acceptable flow rates are currently being investigated. PMID:1366966

Wales, D S; Sagar, B F

1990-01-01

90

A radioactive ion beam facility , SIRIUS, at ISIS  

SciTech Connect

A description is given of the radioactive ion beam facility, SIRIUS, proposed to be built at ISIS, the world leading pulsed neutron source. Up to 100 {mu}A of 800 MeV protons from the ISIS synchrotron will be taken down a new beam line into a target station complex where radioactive nuclei will be formed as a result of the interaction with the target. The nuclei are subsequently ionised and accelerated to 200 kV. The beam passes through a broad range spectrometer to provide several beams of different ion species simultaneously. One beam passes through a high resolution spectrometer and is accelerated in an RFQ and a superconducting linear accelerator to 10 MeV/amu, for nuclear physics research. The other beams are taken to a low energy experimental area.

Bennett, J R J [CLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, OX11 0QX (United Kingdom)

1999-04-26

91

A radioactive ion beam facility , SIRIUS, at ISIS  

NASA Astrophysics Data System (ADS)

A description is given of the radioactive ion beam facility, SIRIUS, proposed to be built at ISIS, the world leading pulsed neutron source. Up to 100 ?A of 800 MeV protons from the ISIS synchrotron will be taken down a new beam line into a target station complex where radioactive nuclei will be formed as a result of the interaction with the target. The nuclei are subsequently ionised and accelerated to 200 kV. The beam passes through a broad range spectrometer to provide several beams of different ion species simultaneously. One beam passes through a high resolution spectrometer and is accelerated in an RFQ and a superconducting linear accelerator to 10 MeV/amu, for nuclear physics research. The other beams are taken to a low energy experimental area.

Bennett, J. R. J.

1999-04-01

92

Wear Measurements By Means Of Radioactive Ion Implantation  

Microsoft Academic Search

Radioactive ion implantation allows non-contacting, online wear measurements with sub micrometric sensitivity to be performed, by monitoring the removed and\\/or residual activity on parts subject to wear. Comparative studies of different materials, including those who exhibit a low resistance to radiation damage, can be easily performed by means of this technique. A project has started at the TTT3 tandem of

L. Gialanella; G. Imbriani; V. Roca; M. Romano; N. de Cesare; A. D'Onofrio; F. Terrasi; H. W. Becker; D. Rogalla; A. Stephan; F. Strieder; Z. Fulop; G. Gyurky; E. Somorjai; M. Russo; D. Daliento; N. Sanseverino

2003-01-01

93

Uptake of metal ions on humic acids  

SciTech Connect

The kinetics, the sorption capacities, pH and temperature dependence of sorption of humic acids (HAs) of Turkish brown coals with respect to Zn(II), Cu(II), Ni(II), Co(II) and Pb(II) ions were investigated, and the roles of the carboxylic and phenolic groups in the adsorption of metals ion on HAs were searched in this work. These metal ions are able to form complex compounds with carboxylic and phenolic groups of HAs. Adsorption equilibrium was achieved in between 50 and 60 min for all studied cations. HAs extracted from different brown coals have been characterized by chemical and physical methods. The chemical properties of HAs showed differences depending on the source from which they were obtained. The sorption of metals on the surface of HAs depends strongly on the pH, and sorption decreases with decreasing pH. Maximum removal of metal ions was demonstrated at pH values of 4.1-5.0. The Langmuir adsorption isotherm was used to describe observed sorption phenomena. The {Delta}G{sup 0} became negative as the temperature increased, and so the equilibrium constant decreased slightly. The investigation proved that the HAs are suitable materials for the studied heavy metal ion removal from aqueous solution and could be considered as potential material for purification of effluent polluted with toxic metal ions.

Pehlivan, E.; Arslan, G. [Selcuk University, Konya (Turkey)

2006-09-15

94

Metal-ion recycle technology for metal electroplating waste waters  

SciTech Connect

As a result of a collaboration with Boeing Aerospace, the authors have begun a program to identify suitable treatments or to develop new treatments for electroplating baths. The target baths are mixed-metal or alloy baths that are being integrated into the Boeing electroplating complex. These baths, which are designed to replace highly toxic chromium and cadmium baths, contain mixtures of two metals, either nickel-tungsten, nickel-zinc, or zinc-tin. This report reviews the literature and details currently available on emerging technologies that could affect recovery of metals from electroplating baths under development by Boeing Aerospace. This literature survey summarizes technologies relevant to the recovery of metals from electroplating processes. The authors expanded the scope to investigate single metal ion recovery technologies that could be applied to metal ion recovery from alloy baths. This review clearly showed that the electroplating industry has traditionally relied on precipitation and more recently on electrowinning as its waste treatment methods. Despite the almost ubiquitous use of precipitation to remove contaminant metal ions from waste electroplating baths and rinse waters, this technology is clearly no longer feasible for the electroplating industry for several reasons. First, disposal of unstabilized sludge is no longer allowed by law. Second, these methods are no longer adequate as metal-removal techniques because they cannot meet stringent new metal discharge limits. Third, precious resources are being wasted or discarded because these methods do not readily permit recovery of the target metal ions. As a result, emerging technologies for metal recovery are beginning to see application to electroplating waste recycle. This report summarizes current research in these areas. Included are descriptions of various membrane technologies, such as reverse osmosis and ultrafiltration, ion exchange and chelating polymer technology, and electrodialysis.

Sauer, N.N.; Smith, B.F.

1993-06-01

95

Solvation of isolated transition metal ions.  

National Technical Information Service (NTIS)

X-ray absorption spectroscopy is used to study the structure of transition metal ions as they encounter excess solvent and dissolve; more particularly, Cu in bentonite, with methanol solvent. The distance between the Cu ion and the oxygen atom increases b...

S. R. Wasserman K. A. Carrado

1994-01-01

96

Reactions of fulvic acid with metal ions  

Microsoft Academic Search

Fulvic acid is a water-soluble humic material that occurs widely in soils and waters and that tends to form water-soluble and water-insoluble complexes with a variety of metal ions, some of which are toxic. This paper presents information on the conditions under which the different types of FA-metal complexes are formed.

M. Schnitzer; H. Kerndorff

1981-01-01

97

Adsorption of metal ions on bed sediments  

Microsoft Academic Search

The adsorption of lead and zinc ions on bed sediments of the River Kali in western Uttar Pradesh, India, has been studied. The role of the coarser sediment fraction (210-250 jtm) in controlling metal pollution has been elucidated and compared to those of the clay and silt fractions. The parameters controlling metal uptake, viz., solution pH, sediment dose, contact time,

C. K. JAIN; D. RAM

1998-01-01

98

BEARS: A radioactive ion beam initiative at LBNL  

SciTech Connect

BEARS is an initiative to develop a radioactive ion-beam capability at Lawrence Berkeley National Laboratory. The aim is to produce isotopes at an existing medical cyclotron and to accelerate them at the 88{sup {double_prime}} Cyclotron. To overcome the 300-meter physical separation of these two accelerators, a carrier-gas transport system will be used. At the terminus of the capillary, the carrier gas will be separated and the isotopes will be injected into the 88{sup {double_prime}} Cyclotron{close_quote}s Advanced Electron Cyclotron Resonance ion source. The first radioactive beams to be developed will include 20-min {sup 11}C and 70-sec {sup 14}O, produced by (p, n) and (p, {alpha}) reactions on low-Z targets. Tests at the 88{sup {double_prime}} Cyclotron lead to projections of initial {sup 11}C beams of 2{times}10{sup 8}&hthinsp;ions/sec {sup 14}O beams of 1{times}10{sup 6}&hthinsp;ions/sec. Construction of BEARS is expected to be completed in the spring of 1999. {copyright} {ital 1999 American Institute of Physics.}

Powell, J.; Guo, F.Q.; Joosten, R.; Larimer, R.-M.; Lyneis, C.M.; McMahan, P.; Moltz, D.M.; Norman, E.B.; O`Neil, J.P.; Rowe, M.W.; VanBrocklin, H.F.; Wutte, D.; Xie, Z.Q.; Xu, X.J.; Cerny, J. [Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720 (United States)] Haustein, P.E. [Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973 (United States)

1999-06-01

99

BEARS: A radioactive ion beam initiative at LBNL  

SciTech Connect

BEARS is an initiative to develop a radioactive ion-beam capability at Lawrence Berkeley National Laboratory. The aim is to produce isotopes at an existing medical cyclotron and to accelerate them at the 88'' Cyclotron. To overcome the 300-meter physical separation of these two accelerators, a carrier-gas transport system will be used. At the terminus of the capillary, the carrier gas will be separated and the isotopes will be injected into the 88'' Cyclotron's Advanced Electron Cyclotron Resonance ion source. The first radioactive beams to be developed will include 20-min {sup 11}C and 70-sec {sup 14}O, produced by (p, n) and (p, {alpha}) reactions on low-Z targets. Tests at the 88'' Cyclotron lead to projections of initial {sup 11}C beams of 2x10{sup 8} ions/sec {sup 14}O beams of 1x10{sup 6} ions/sec. Construction of BEARS is expected to be completed in the spring of 1999.

Powell, J.; Guo, F. Q.; Joosten, R.; Larimer, R.-M.; Lyneis, C. M.; McMahan, P.; Moltz, D. M.; Norman, E. B.; O'Neil, J. P.; Rowe, M. W.; VanBrocklin, H. F.; Wutte, D.; Xie, Z. Q.; Xu, X. J.; Cerny, Joseph [Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720 (United States); Haustein, P. E. [Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973 (United States)

1999-06-10

100

Serum metal ion levels after second-generation metal-on-metal total hip arthroplasty  

Microsoft Academic Search

Introduction  Metal-on-metal bearings for total hip arthroplasty are increasing in popularity. However, metal ion toxicity, metal hypersensitivity,\\u000a and metal carcinogenicity are the causes concern for patients with metal-on-metal hip replacement. We investigated serum levels\\u000a of cobalt and chromium ions in patients with successfully implanted second-generation metal-on-metal total hip arthroplasty\\u000a (THA) using PINNACLE-A (DePuy, Warsaw, IN, USA).\\u000a \\u000a \\u000a \\u000a \\u000a Materials and methods  Thirty-three patients underwent

Takao Imanishi; Masahiro Hasegawa; Akihiro Sudo

2010-01-01

101

Upgraded vacuum arc ion source for metal ion implantation  

SciTech Connect

Vacuum arc ion sources have been made and used by a large number of research groups around the world over the past twenty years. The first generation of vacuum arc ion sources (dubbed ''Mevva,'' for metal vapor vacuum arc) was developed at Lawrence Berkeley National Laboratory in the 1980s. This paper considers the design, performance parameters, and some applications of a new modified version of this kind of source which we have called Mevva-V.Ru. The source produces broad beams of metal ions at an extraction voltage of up to 60 kV and a time-averaged ion beam current in the milliampere range. Here, we describe the Mevva-V.Ru vacuum arc ion source that we have developed at Tomsk and summarize its beam characteristics along with some of the applications to which we have put it. We also describe the source performance using compound cathodes.

Nikolaev, A. G.; Oks, E. M.; Savkin, K. P.; Yushkov, G. Yu. [High Current Electronics Institute, Siberian Division of the Russian Academy of Science, Tomsk 634055 (Russian Federation); Brown, I. G. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

2012-02-15

102

Upgraded vacuum arc ion source for metal ion implantation.  

PubMed

Vacuum arc ion sources have been made and used by a large number of research groups around the world over the past twenty years. The first generation of vacuum arc ion sources (dubbed "Mevva," for metal vapor vacuum arc) was developed at Lawrence Berkeley National Laboratory in the 1980s. This paper considers the design, performance parameters, and some applications of a new modified version of this kind of source which we have called Mevva-V.Ru. The source produces broad beams of metal ions at an extraction voltage of up to 60 kV and a time-averaged ion beam current in the milliampere range. Here, we describe the Mevva-V.Ru vacuum arc ion source that we have developed at Tomsk and summarize its beam characteristics along with some of the applications to which we have put it. We also describe the source performance using compound cathodes. PMID:22380197

Nikolaev, A G; Oks, E M; Savkin, K P; Yushkov, G Yu; Brown, I G

2012-02-01

103

Ion exchange of alkali metals on hydrous titanium dioxide in neutral and alkaline solutions  

Microsoft Academic Search

Selectivity of hydrous titanium dioxide as an ion exchanger for alkali metal and tetraalkylammonium ions, has been studied using radioactive indicators:22Na and137Cs. The equilibrium distribution of trace amounts of sodium and cesium ions between the exchanger and aqueous solutions containing macroamounts of other univalent cations was studied over the temperature range of 15 to 80°C. The selectivity sequence in slightly

A. Bilewicz; R. Dybczynski; J. Narbutt

1991-01-01

104

Computational Design of Metal Ion Sequestering Agents  

SciTech Connect

Organic ligands that exhibit a high degree of metal ion recognition are essential precursors for developing separation processes and sensors for metal ions. Since the beginning of the nuclear era, much research has focused on discovering ligands that target specific radionuclides. Members of the Group 1A and 2A cations (e.g., Cs, Sr, Ra) and the f-block metals (actinides and lanthanides) are of primary concern to DOE. Although there has been some success in identifying ligand architectures that exhibit a degree of metal ion recognition, the ability to control binding affinity and selectivity remains a significant challenge. The traditional approach for discovering such ligands has involved lengthy programs of organic synthesis and testing that, in the absence of reliable methods for screening compounds before synthesis, have resulted in much wasted research effort.

Hay, Benjamin P.; Rapko, Brian M.

2005-06-15

105

Computational Design of Metal Ion Sequestering Agents  

SciTech Connect

Organic ligands that exhibit a high degree of metal ion recognition are essential precursors for developing separation processes and sensors for metal ions. Since the beginning of the nuclear era, much research has focused on discovering ligands that target specific radionuclides. Members of the Group 1A and 2A cations (e.g., Cs, Sr, Ra) and the f-block metals (actinides and lanthanides) are of primary concern to DOE. Although there has been some success in identifying ligand architectures that exhibit a degree of metal ion recognition, the ability to control binding affinity and selectivity remains a significant challenge. The traditional approach for discovering such ligands has involved lengthy programs of organic synthesis and testing that, in the absence of reliable methods for screening compounds before synthesis, have resulted in much wasted research effort.

Hay, Benjamin P.; Rapko, Brian M.

2006-06-01

106

Metal vapor arc ion plating  

DOEpatents

A method and apparatus for ion plating are described. The apparatus uses more negative than a first electrode voltage in a vacuum arc remelt system to attract low energy ions from the anode electrode to the article to be plated. 2 figs.

Bertram, L.A.; Fisher, R.W.; Mattox, D.M.; Zanner, F.J.

1986-09-09

107

Separation of metal ions in nitrate solution by ultrasonic atomization  

NASA Astrophysics Data System (ADS)

In the ultrasonic atomization of metal nitrate solutions, the molar ratio of metal ions is changed between solution and mist. Small molar metal ions tend to be transferred to mist by ultrasonic wave acceleration, while large molar ions tend to remain in solution. As a result, metal ions can be separated by ultrasonic atomization. We show experimental data and propose a conceptual mechanism for the ultrasonic separation of metal ions.

Sato, Masanori; Ikeno, Masayuki; Fujii, Toshitaka

2004-11-01

108

Separation of metal ions in nitrate solution by ultrasonic atomization.  

PubMed

In the ultrasonic atomization of metal nitrate solutions, the molar ratio of metal ions is changed between solution and mist. Small molar metal ions tend to be transferred to mist by ultrasonic wave acceleration, while large molar ions tend to remain in solution. As a result, metal ions can be separated by ultrasonic atomization. We show experimental data and propose a conceptual mechanism for the ultrasonic separation of metal ions. PMID:15538875

Sato, Masanori; Ikeno, Masayuki; Fujii, Toshitaka

2004-11-15

109

Wear Measurements By Means Of Radioactive Ion Implantation  

NASA Astrophysics Data System (ADS)

Radioactive ion implantation allows non-contacting, online wear measurements with sub micrometric sensitivity to be performed, by monitoring the removed and/or residual activity on parts subject to wear. Comparative studies of different materials, including those who exhibit a low resistance to radiation damage, can be easily performed by means of this technique. A project has started at the TTT3 tandem of the University ``Federico II'' in Naples, Italy, in order to exploit such technique using a 7Be ion beam, that was developed to study the astrophysical important reaction 7Be(p,?)8B. The 7Be ion beam is produced using a ion sputter source and accelerated to an energy up to 8.0 MeV. A novel setup allows control of the implanted ion depth distribution, and is a crucial point for the application of this technique. The 7Be ion beam production and implantation procedures are discussed. Finally, the results of some test measurements are presented.

Gialanella, L.; Imbriani, G.; Roca, V.; Romano, M.; de Cesare, N.; D'Onofrio, A.; Terrasi, F.; Becker, H. W.; Rogalla, D.; Stephan, A.; Strieder, F.; Fulop, Z.; Gyurky, G.; Somorjai, E.; Russo, M.; Daliento, D.; Sanseverino, N.

2003-08-01

110

MEVVA ion source for high current metal ion implantation  

SciTech Connect

The MEVVA (Metal Vapor Vacuum Arc) ion source is a new kind of source which can produce high current beams of metal ions. Beams of a wide range of elements have been produced, spanning the periodic table from lithium up to and including uranium. The source extraction voltage is up to 60 kV, and we are increasing this up to 120 kV. A total ion beam current of over 1 Ampere has been extracted from the present embodiment of the concept, and this is not an inherent limit. The ion charge state distribution varies with cathode material and arc current, and beams like Li/sup +/, Co/sup +,2+,3+/ and U/sup 3+,4+,5+,6+/ for example, are typical; thus the implantation energy can be up to several hundred kilovolts without additional acceleration. The ion source has potential applications for ion implantation and ion beam mixing for achievement of improved corrosion resistance or wear resistance in metals or surface modification of ceramic materials and semiconductors. Here we outline the source and its performance, and describe some very preliminary implantation work using this source.

Brown, I.; Washburn, J.

1986-07-01

111

Computational Design of Metal Ion Sequestering Agents  

SciTech Connect

Organic ligands that exhibit a high degree of metal ion recognition are essential precursors for developing separation processes and sensors for metal ions. Since the beginning of the nuclear era, much research has focused on discovering ligands that target specific radionuclides. Members of the Group 1A and 2A cations (e.g., Cs, Sr, Ra) and the f-block metals (actinides and lanthanides) are of primary concern to DOE. Although there has been some success in identifying ligand architectures that exhibit a degree of metal ion recognition, the ability to control binding affinity and selectivity remains a significant challenge. The traditional approach for discovering such ligands has involved lengthy programs of organic synthesis and testing that, in the absence of reliable methods for screening compounds before synthesis, have resulted in much wasted research effort. This project seeks to enhance and strengthen the traditional approach through computer-aided design of new and improved host molecules. Accurate electronic structure calculations are coupled with experimental data to provide fundamental information about ligand structure and the nature of metal-donor group interactions (design criteria). This fundamental information then is used in a molecular mechanics model (MM) that helps us rapidly screen proposed ligand architectures and select the best members from a set of potential candidates. By using combinatorial methods, molecule building software has been developed that generates large numbers of candidate architectures for a given set of donor groups. The specific goals of this project are: • further understand the structural and energetic aspects of individual donor group- metal ion interactions and incorporate this information within the MM framework • further develop and evaluate approaches for correlating ligand structure with reactivity toward metal ions, in other words, screening capability • use molecule structure building software to generate large numbers of candidate ligand architectures for given sets of donor groups • screen candidates and identify ligand architectures that will exhibit enhanced metal ion recognition. These new capabilities are being applied to ligand systems identified under other DOEsponsored projects where studies have suggested that modifying existing architectures will lead to dramatic enhancements in metal ion binding affinity and selectivity. With this in mind, we are collaborating with Professors R. T. Paine (University of New Mexico), K. N. Raymond (University of California, Berkeley), and J. E. Hutchison (University of Oregon), and Dr. B. A. Moyer (Oak Ridge National Laboratory) to obtain experimental validation of the predicted new ligand structures. Successful completion of this study will yield molecular-level insight into the role that ligand architecture plays in controlling metal ion complexation and will provide a computational approach to ligand design.

Hay, Benjamin P.; Rapko, Brian M.

2005-06-15

112

Metal ions affecting the skin and eyes.  

PubMed

The skin and eyes remain in constant exposure to the surrounding environment and are subject to accidental, occupational, and biological risks at all times, Normal development, homeostasis, and repair following injury depend upon appropriate levels of calcium, zinc, magnesium, copper, iron, and minute amounts of other trace metals. Both tissues exist in a permanent state of dynamic equilibrium with the environment whereby cells lost through natural wear and tear are replaced through genetically regulated mitotic patterns. Normal functional requirements of the constituent tissues depend on critical balances between trace metals, metal ion gradients, and specific carrier proteins which are modulated by upregulation of growth factors, cytokines, hormones, and subcellular regulators acting by autocrine, paracrine, and endocrine mechanisms. Metal ion gradients in epidermal tissues serve critical functions in basal cell proliferation, post-mitotic migration, and functional differentiation in normal homeostasis and in repair following injury. Toxic mechanisms reflect imbalances in trace metals or interaction between xenobiotic and trace metals through competitive binding key carrier proteins and metabolic pathways leading to trace metal imbalances and functional impairment. Alternatively, toxic injuries result through direct cytotoxic action of metal ions on cell membranes, intercellular communication, RNA and DNA damage, and mutagenic change. Arsenic is the only primary carcinogen in the skin following ingestion or topical exposure; beryllium, aluminum, and zirconium are a cause of granuloma. Aluminum as a cause for breast cancer is equivocal. Metal toxicities in the eye result from direct accidental or occupational exposure and systemic uptake of neurotoxic metals and their action on the retina and optic nerve. Calcium, zinc, magnesium, and iron are essential trace elements in eye development and physiology but silver, gold, lead, and mercury are absorbed through optic membranes or from the circulation to accumulate in the vitreous leading to local or systemic action. Lead, mercury, cadmium, aluminum, and other xenobiotic metals are implicated in structural and physiological damage in the mammalian eye. Thallium shows an affinity for melanin. PMID:21473382

Lansdown, Alan B G

2011-01-01

113

Recent results with radioactive ion beams in Brasil (RIBRAS)  

NASA Astrophysics Data System (ADS)

The RIBRAS facility (Radiactive Ion Beams in Brasil) is installed next to the 8 MV Pelletron Tandem of the Nuclear Physics Laboratory of the Institute of Physics of the University of Sa~o Paulo. It consists of two superconducting solenoids with maximum magnetic field of B=6.5T. Light radioactive ion beams are produced through transfer reactions, using solid or gaseous production targets of Be, LiF, 3He etc. The solenoids make a magnetic rigidity selection and the use of the two solenoids with a degrader between them allows the production of quite pure secondary beams. Beams of 6He, 8Li, 7Be, 10Be, 8B, 12B are currently produced and used to study elastic, inelastic, and transfer reactions on a variety of light, medium mass and heavy secondary targets. Some examples of reactions recently studied are presented below.

Lépine-Szily, A.; Lichtenthäler, R.; Guimara~es, V.; Mendes, D. R., Jr.; Descouvemont, P.; de Faria, P. N.; Barioni, A.; Leistenschneider, E.; Morcelle, V.; Morais, M. C.; Pires, K. C. C.; Condori, R. Pampa; Assunça~o, M. M.; Scarduelli, V.; Gasques, L. R.; Zamora, J. C.

2012-10-01

114

Method for permanently storing radioactive ion exchanger resins  

SciTech Connect

A method is claimed for forming a hardened product containing a radioactive ion exchanger resin in a condition for permanent, noncontaminating storage, by the steps of: providing, before fixing, a mass of such ion exchanger resin saturated in water, the resin being at least one resin selected from the group consisting of spherical resins and powdered resins; mixing the resin mass, with stirring, with a blast furnace cement having a composition which causes it to exhibit slow initial hardening, high sulfate resistance and low hydration heat and with a quantity of additional water equal in weight to 20% to 40% of the weight of the blast furnace cement; and allowing the resulting mixture to harden at room temperature.

Kunze, S.; Eden, G.; Koster, R.

1984-11-20

115

Targets for ion sources for RIB generation at the Holifield Radioactive Ion Beam Facility  

SciTech Connect

The Holifield Radioactive Ion Beam Facility (HRIBF), now under construction at the Oak Ridge National Laboratory, is based on the use of the well-known on-line isotope separator (ISOL) technique in which radioactive nuclei are produced by fusion type reactions in selectively chosen target materials by high-energy proton, deuteron, or He ion beams from the Oak Ridge Isochronous Cyclotron (ORIC). Among several major challenges posed by generating and accelerating adequate intensities of radioactive ion beams (RIBs), selection of the most appropriate target material for production of the species of interest is, perhaps, the most difficult. In this report, we briefly review present efforts to select target materials and to design composite target matrix/heat-sink systems that simultaneously incorporate the short diffusion lengths, high permeabilities, and controllable temperatures required to effect maximum diffusion release rates of the short-lived species that can be realized at the temperature limits of specific target materials. We also describe the performance characteristics for a selected number of target ion sources that will be employed for initial use at the HRIBF as well as prototype ion sources that show promise for future use for RIB applications.

Alton, G.D.

1995-12-31

116

Metal ion complexation by ionizable crown ethers  

SciTech Connect

During the report period a variety of new lipophilic ionizable crown ethers with pendent proton-ionizable groups has been synthesized. In addition a series of proton-ionizable crown ethers without lipophilic groups was prepared to study how structural variations within the ligand influence metal ion complexation in homogeneous media as assessed by NMR spectroscopy or titration calorimetry. A third class of new metal ion-complexing agents is a series of lipophilic acyclic polyether dicarboxylic acids. Competitive solvent extractions of alkali metal and alkaline earth cations and of the mixed species have been conducted to reveal the influence of ring size, nature and attachment site of the lipophilic group, sidearm length, and proton-ionizable group identity and location upon the selectivity and efficiency of metal ion complexation. In addition to such studies of structural variation within the lipophilic proton-ionizable crown ether, the effect of changing the organic solvent and variation of the stripping conditions have been assessed. The ability of proton- ionizable crown ethers to function as selective metal ion carriers in liquid membrane transport processes has been examined in both bulk liquid membrane and polymer-supported liquid membrane transport systems. New acyclic and cyclic polyether carboxylic acid resins have been prepared by condensation polymerization and characterized.

Bartsch, R.A.

1990-06-01

117

Novel metal ion surface modification technique  

SciTech Connect

We describe a method for applying metal ions to the near-surface region of solid materials. The added species can be energetically implanted below the surface or built up as a surface film with an atomically mixed interface with the substrate; the metal ion species can be the same as the substrate species or different from it, and more than one kind of metal species can be applied, either simultaneously or sequentially. Surface structures can be fabricated, including coatings and thin films of single metals, tailored alloys, or metallic multilayers, and they can be implanted or added onto the surface and ion beam mixed. We report two simple demonstrations of the method: implantation of yttrium into a silicon substrate at a mean energy of 70 keV and a dose of 1 {times} 10{sup 16} atoms/cm{sup 2}, and the formation of a titanium-yttrium multilayer structure with ion beam mixing to the substrate. 17 refs., 3 figs.

Brown, I.G.; Godechot, X.; Yu, K.M.

1990-10-01

118

Ion exchangers in radioactive waste management: natural Iranian zeolites.  

PubMed

Five samples of natural zeolites from different parts of Iran were chosen for this study. In order to characterize and determine their structures, X-ray diffraction and infrared spectrometry were carried out for each sample. The selective absorption properties of each zeolite were found by calculating the distribution coefficient (K(d)) of various simulated wastes which were prepared by spiking the radionuclides with (131)I, (99)Mo, (153)Sm, (140)La and (147)Nd. All the zeolite samples used in this study had extremely high absorption value towards (140)La; clinoptolite from Mianeh and analsite from Ghalehkhargoshi showed good absorption for (147)Nd; clinoptolite from Semnan and clinoptolite from Firozkoh showed high absorption for (153)Sm; mesolite from Arababad Tabas showed good absorption for (99)Mo; and finally mesolite from Arababad Tabas, clinoptolite from Semnan and clinoptolite from Firozkoh could be used to selectively absorb (131)I from the stimulated waste which was prepared. The natural zeolites chosen for these studies show a similar pattern to those synthetic ion exchangers in the literature and in some cases an extremely high selectivity towards certain radioactive elements. Hence the binary separation of radioactive elements could easily be carried out. Furthermore, these zeolites, which are naturally occurring ion exchangers, are viable economically and extremely useful alternatives in this industry. PMID:16099667

Nilchi, A; Maalek, B; Khanchi, A; Ghanadi Maragheh, M; Bagheri, A; Savoji, K

2005-08-15

119

Accelerating Radioactive Ion Beams With REX-ISOLDE  

SciTech Connect

The post accelerator REX-ISOLDE is installed at the ISOLDE facility at CERN, where a broad variety of radioactive ions can be addressed. Since the end of 2001 beams at the final energy of 2.2 MeV/u are available. REX-ISOLDE uses a unique system of beam bunching and charge breeding. First a Penning trap accumulates and bunches the ions, which are delivered as a quasi-continuous beam from the ISOLDE target-ion-source, and then an electron beam ion source (EBIS) charge-breeds them to a mass-to-charge ratio below 4.5. This enables a very compact design for the following LINAC, consisting of a 4 rod RFQ, an IH structure and three 7-gap-resonators. The later ones allow a variation of the final energy between 0.8 and 2.2 MeV/u. Although the machine is still in the commissioning phase, first physics experiments have been done with neutron rich Na and Mg isotopes and 9Li. A total efficiency of several percent has already been obtained.

Ames, F.; Emhofer, S.; Habs, D.; Kester, O.; Reisinger, K.; Sieber, T. [Sektion Physik, LMU, Muenchen, D-85748 Garching (Germany); Bollen, G. [NSCL, Michigan State University, East Lansing, MI 48824 (United States); Cederkaell, J.; Forstner, O.; Wenander, F. [CERN, CH-1211 Geneva 23 (Switzerland); Huber, G.; Wolf, B. [Institut fuer Physik, J. Gutenberg-Universitaet, D-55099 Mainz (Germany); Schwalm, D.; Hahn, R. von [Max-Planck-Institut fuer Kernphysik, D-69117 Heidelberg (Germany); Bergh, P. van den; Duppen, P. van [Instituut voor Kern- en Stralingsfysica, K.U. Leuven, B-3001 Leuven (Belgium)

2003-08-26

120

Recent ion source developments for production of radioactive beams (invited)  

NASA Astrophysics Data System (ADS)

Presently, worldwide radioactive ion beam facilities based on the separator online are the main instruments for nuclear structure study and for solving many important questions about astrophysics. Investigations of short-lived neutron-rich and neutron-deficient nuclei, that are far from stability give a unique possibility for testing many aspects of modern nuclear structure theory. Therefore, the development of highly efficient, selective, and fast ion source-target systems (ISTS) for modern and next generation ISOL facilities is the crucial point for future progress of nuclear science and experimental astrophysics. The last decade demonstrates a burst of new developments in the field of ion source-target systems for ISOL installation use. The main task of this review is to show the latest results obtained with different types of ion sources, specially designed for short-lived isotope production, and to designate some directions of the ISTS development that can be noticed presently and very likely will be used in the near future.

Panteleev, V. N.

2004-05-01

121

Solidification in cement of ion-exchange resins from LOMI (Low Oxidation State Metal Ion) decontamination  

SciTech Connect

Chemical decontamination of operating nuclear power plants is performed to remove radioactive metal oxides from pipes and equipment thereby reducing the radiation exposure to personnel performing inspection and maintenance. The LOMI (Low Oxidation State Metal Ion) process is widely used to perform this decontamination. At the end of the decontamination operations, the chemicals remaining in solution are removed by ion exchange resins. The resins are subsequently solidified in metal liners using cement, transported and buried at an approved burial site. The work covered by this report was undertaken because of an incomplete solidification of the ion exchange resins. The details of the decontamination operations have been described. At the time the problem arose, a preliminary investigation led to the conclusion that the unsolidified resin resulted from inadequate mixing caused by the formation of hydrated gel. The purpose of this project was to develop an understanding of the variables affecting the formation of the gel and to devise methods to avoid its formation. Additionally, safe limits would be defined that would assure the complete solidification in cement of ion exchange resins used in LOMI chemical decontaminations. 5 refs., 3 figs., 6 tabs.

Not Available

1990-08-01

122

Assessment of recycling or disposal alternatives for radioactive scrap metal  

SciTech Connect

The US Department of Energy, Office of Environmental Restoration and Waste Management, is participating with the Organization for Economic Cooperation and Development (OECD) is an evaluation of management alternatives for radioactive scarp metals. For this purpose, Argonne National Laboratory is assessing alternatives for radioactive scrap metals. For this purpose, Argonne National Laboratory is assessing environmental and societal implications of recycling and/or disposal process alternatives (with metal replacement). Findings will be presented in a report from the OECD Task Group. This paper focuses on the radiological risk assessment and dose estimate sensitivity analysis. A ``tiered`` concept for release categories, with and without use restrictions, is being developed. Within the tiers, different release limits may be indicated for specific groupings of radionuclides. Depending on the spectrum of radionuclides that are present and the level of residual activity after decontamination and/or smelting, the scrap may be released for unrestricted public use or for specified public uses, or it may be recycled within the nuclear industry. The conversatism of baseline dose estimates is examined, and both more realistic parameter values and protective measures for workers are suggested.

Murphie, W.E.; Lilly, M.J. III [USDOE Assistant Secretary for Environmental Restoration and Waste Management, Washington, DC (United States). Office of Environmental Restoration; Nieves, L.A.; Chen, S.Y. [Argonne National Lab., IL (United States)

1993-10-01

123

Operational characteristics of a metal vapor vacuum arc ion source  

Microsoft Academic Search

The MEVVA ion source can produce high current pulsed beams of metallic ions using a metal vapor vacuum arc discharge as the plasma medium from which the ions are extracted. In this study, the operational characteristics of the MEVVA IV ion sources are summarized. Results are presented of measurements of the ion beam current as a function of arc current

Hiroshi Shiraishi; Ian G. Brown

1990-01-01

124

Ion implantation makes metals last longer  

SciTech Connect

Ion implantation is an atomic level surface treatment that modifies the structure of a metal's near-surface region, producing a new alloy without altering part dimensions. The process is most often used to enhance wear resistance, but sometimes is chosen to improve corrosion resistance. Surfaces subject to adhesive and abrasive wear last anywhere from two to 100 times longer after they have been ion implanted. In the process, ions of the element or elements to be implanted are accelerated toward the target surface. When the beam strikes the surface, the ions become embedded in it to a depth of up to 1[mu]m, producing a new alloy in the implanted region. The concentration-verses-depth profile of implanted ions is controlled by the amount of element used, its mass, and the accelerating voltage.

Holtkamp, B. (Implant Sciences Corp., Wakefield, MA (United States))

1993-12-01

125

IMMUNOASSAYS FOR METAL IONS. (R824029)  

EPA Science Inventory

Abstract Antibodies that recognize chelated forms of metal ions have been used to construct immunoassays for Cd(II), Hg(II), Pb(II), and Ni(II). In this paper, the format of these immunoassays is described and the binding properties of three monoclonal antibodies direc...

126

Development of a Be-7 beam: Techniques for the ionization of radioactive metallic elements (abstract)  

NASA Astrophysics Data System (ADS)

The Louvain-la-Neuve ECR ion source is used to ionize metallic radioactive elements like Be-7 (T1/2=53d) for postacceleration in its radioactive beam facility. Because of the minute quantities of primary material available, dedicated techniques had to be developed to inject the radioactive atoms in a controlled manner and to recycle the atoms lost on the plasma chamber walls. For this purpose, a heated plasma chamber has been constructed which allows the use of ``on-line chemistry in the source'' to effectively recycle the deposited material. The presence of a radioactive tracer proved to be a strong diagnostic tool to locate the material loss in the different parts of the source. This development resulted in the production of a postaccelerated beam of Be-7 in 1+ and 2+ charge states. Up to 110 h of continuous beam have been provided with primary material quantities of a few ng. The total efficiency of the source reached a few percent. These beams were initially developed for experiments in nuclear physics. The implantation of Be-7 is now also used as a powerful tool to measure the wear properties of various materials like ceramics and amorphous carbon layers. This will be illustrated with a few examples.

Gaelens, M.; Loiselet, M.; Ryckewaert, G.

2004-05-01

127

Hydrogen production during processing of radioactive sludge containing noble metals  

SciTech Connect

Hydrogen was produced when radioactive sludge from Savannah River Site radioactive waste containing noble metals was reacted with formic acid. This will occur in a process tank in the Defense Waste Facility at SRS when waste is vitrified. Radioactive sludges from four tanks were tested in a lab-scale apparatus. Maximum hydrogen generation rates varied from 5 {times}10{sup {minus}7} g H{sub 2}/hr/g of sludge from the least reactive sludge (from Waste Tank 51) to 2 {times}10{sup {minus}4} g H{sub 2}/hr/g of sludge from the most reactive sludge (from Waste Tank 11). The time required for the hydrogen generation to reach a maximum varied from 4.1 to 25 hours. In addition to hydrogen, carbon dioxide and nitrous oxide were produced and the pH of the reaction slurry increased. In all cases, the carbon dioxide and nitrous oxide were generated before the hydrogen. The results are in agreement with large-scale studies using simulated sludges.

Ha, B.C.; Ferrara, D.M.; Bibler, N.E.

1992-09-01

128

Low energy nuclear reactions with RIBRAS, Radioactive Ion Beam in Brasil, system  

Microsoft Academic Search

RIBRAS, Radioactive Ion beam in Brasil, is a system based on superconducting solenoids which can produce low energy RNB (Radioactive Nuclear Beams) at the University of São Paulo, Brazil. Secondary radioactive beams of light particles such as 6He, 7Be and 8Li have been produced and low energy elastic scattering and transfer reaction experiments have been performed. The recent scientific program

V. Guimarães; A. Lépine-Szily; R. Lichtenthäler; P. N. de Faria; A. Barioni; K. C. C. Pires; V. Morcelle; D. R. Mendes; J. C. Zamora; M. C. Morais; R. P. Condori; E. A. Benjamim; D. S. Monteiro; E. Crema; A. M. Moro; J. Lubian

2011-01-01

129

Status of the ESR and Prospects for Radioactive Ion Beams  

SciTech Connect

This contribution presents the status of the Experimental Storage Ring ESR at GSI after nearly 10 years of experiments with electron-cooled primary and secondary heavy ion beams, and discusses possible upgrades for the near future. The major fraction of the ESR beam time was dedicated to atomic spectroscopy experiments with fully stripped or few-electron heavy ions up to uranium. Remarkable nuclear physics results came, so far, mainly from the precise Schottky mass spectrometry with cooled radioactive fragments. The experimental program of a future--very likely modified--ESR aims at nuclear physics experiments with secondary, neutron-rich or neutron-deficient nuclides with lifetimes in the order of 1 s. Luminosities of up to 1{times}10{sup 29} cm{sup {minus}2}s{sup {minus}1} for collisions with protons of an internal H{sub 2} target and up to 1{times}10{sup 28} cm{sup {minus}2}s{sup {minus}1} for electron-nucleus interactions in the collider mode will be required. These values might b e in reach by improving both the collection efficiency and the cooling speed for the secondary nuclei and by further increasing the primary beam intensity at the heavy ion accelerator complex UNILAC/SIS.

Franzke, B.; Beckert, K.; Groening, L.; Nolden, F.; Steck, M.

2000-12-31

130

Biosensors for the Detection of Heavy Metal Ions.  

National Technical Information Service (NTIS)

Phytochelatins, metallothioneins and glutathione are under investigation as biological components for the development of biosensors for heavy metal ion detection in aqueous solutions. These peptides/proteins selectively bind heavy metal ions by thiolate c...

R. Hilpert F. Binder M. H. Zenk

1989-01-01

131

Metal Ion Measurement: One Surgeon's 30 Year Perspective  

Center for Biologics Evaluation and Research (CBER)

Text VersionSerum Co & Cr Levels Metal Ion Measurement: One Surgeon's 30 Year ... Page 3. Is Measurement of Metal Ions Appropriate and/or Clinically Useful ? ... More results from www.fda.gov/downloads/advisorycommittees/committeesmeetingmaterials

132

Substrate Profile and Metal-ion Selectivity of Human Divalent Metal-ion Transporter-1*  

PubMed Central

Divalent metal-ion transporter-1 (DMT1) is a H+-coupled metal-ion transporter that plays essential roles in iron homeostasis. DMT1 exhibits reactivity (based on evoked currents) with a broad range of metal ions; however, direct measurement of transport is lacking for many of its potential substrates. We performed a comprehensive substrate-profile analysis for human DMT1 expressed in RNA-injected Xenopus oocytes by using radiotracer assays and the continuous measurement of transport by fluorescence with the metal-sensitive PhenGreen SK fluorophore. We provide validation for the use of PhenGreen SK fluorescence quenching as a reporter of cellular metal-ion uptake. We determined metal-ion selectivity under fixed conditions using the voltage clamp. Radiotracer and continuous measurement of transport by fluorescence assays revealed that DMT1 mediates the transport of several metal ions that were ranked in selectivity by using the ratio Imax/K0.5 (determined from evoked currents at ?70 mV): Cd2+ > Fe2+ > Co2+, Mn2+ ? Zn2+, Ni2+, VO2+. DMT1 expression did not stimulate the transport of Cr2+, Cr3+, Cu+, Cu2+, Fe3+, Ga3+, Hg2+, or VO+. 55Fe2+ transport was competitively inhibited by Co2+ and Mn2+. Zn2+ only weakly inhibited 55Fe2+ transport. Our data reveal that DMT1 selects Fe2+ over its other physiological substrates and provides a basis for predicting the contribution of DMT1 to intestinal, nasal, and pulmonary absorption of metal ions and their cellular uptake in other tissues. Whereas DMT1 is a likely route of entry for the toxic heavy metal cadmium, and may serve the metabolism of cobalt, manganese, and vanadium, we predict that DMT1 should contribute little if at all to the absorption or uptake of zinc. The conclusion in previous reports that copper is a substrate of DMT1 is not supported.

Illing, Anthony C.; Shawki, Ali; Cunningham, Christopher L.; Mackenzie, Bryan

2012-01-01

133

Materials science and biophysics applications at the ISOLDE radioactive ion beam facility  

NASA Astrophysics Data System (ADS)

The ISOLDE isotope separator facility at CERN provides a variety of radioactive ion beams, currently more than 800 different isotopes from ˜70 chemical elements. The radioisotopes are produced on-line by nuclear reactions from a 1.4 GeV proton beam with various types of targets, outdiffusion of the reaction products and, if possible, chemically selective ionisation, followed by 60 kV acceleration and mass separation. While ISOLDE is mainly used for nuclear and atomic physics studies, applications in materials science and biophysics account for a significant part (currently ˜15%) of the delivered beam time, requested by 18 different experiments. The ISOLDE materials science and biophysics community currently consists of ˜80 scientists from more than 40 participating institutes and 21 countries. In the field of materials science, investigations focus on the study of semiconductors and oxides, with the recent additions of nanoparticles and metals, while the biophysics studies address the toxicity of metal ions in biological systems. The characterisation methods used are typical radioactive probe techniques such as Mössbauer spectroscopy, perturbed angular correlation, emission channeling, and tracer diffusion studies. In addition to these "classic" methods of nuclear solid state physics, also standard semiconductor analysis techniques such as photoluminescence or deep level transient spectroscopy profit from the application of radioactive isotopes, which helps them to overcome their chemical "blindness" since the nuclear half life of radioisotopes provides a signal that changes in time with characteristic exponential decay or saturation curves. In this presentation an overview will be given on the recent research activities in materials science and biophysics at ISOLDE, presenting some of the highlights during the last five years, together with a short outlook on the new developments under way.

Wahl, U.

2011-12-01

134

Intravascular brachytherapy with radioactive stents produced by ion implantation  

NASA Astrophysics Data System (ADS)

About 1 million patients are treated for stenosis of coronary arteries by percutaneous balloon angioplasty annually worldwide. In many cases a so called stent is inserted into the vessel to keep it mechanically open. Restenosis is observed in about 20-30% of these cases, which can be treated by irradiating the stented vessel segment. In our approach, we utilized the stent itself as radiation source by ion implanting 32P. Investigations of the surface properties were performed with special emphasis on activity retention. Clinical data of about 400 patients showed radioactive stents can suppress instent restenosis, but a so called edge effect appeared, which can be avoided by the new ``drug eluting stents''.

Golombeck, M.-A.; Heise, S.; Schloesser, K.; Schuessler, B.; Schweickert, H.

2003-05-01

135

Surrogate reactions for neutron capture with radioactive ion beams  

NASA Astrophysics Data System (ADS)

Neutron capture reactions are responsible for most of the elements heavier than iron, through either the slow or rapid processes of nucleosynthesis. The r process in particular proceeds through very short-lived nuclei on which neutron capture reaction measurements will never be possible. Knowledge of neutron capture cross sections on short-lived nuclei is also important for applications such as nuclear energy, nuclear forensics, and stockpile stewardship science. When the level density at the neutron separation energy is relatively low, for example near closed neutron shells, direct neutron capture often dominates and direct neutron transfer reactions can provide the spectroscopic information needed to calculate the direct capture. However, when the level density is higher, a compound nucleus is formed and statistical mechanisms dominate the decay. While the formation of the compound nucleus can be calculated with optical models, modeling of the decay is less robust. Because of the importance of neutron capture on nuclei away from stability, there have been efforts to validate surrogate reactions for neutron capture that exploit the availability of beams of radioactive nuclei that interact with light targets where reaction products are measured in coincidence with gamma radiation. This talk would summarize efforts to validate a surrogate for neutron capture and the techniques being developed to measure these reactions with beams of radioactive ions.

Cizewski, Jolie A.

2012-10-01

136

Fulvic acid: modifier of metal-ion chemistry  

Microsoft Academic Search

Fulvic acid, which is derived from the decay of plants and animals, is being studied for its role in the transport and toxicity of metal ions in soil and water. It is discussed in relation to the origin of humic substances and its interactions with metal ions. Techniques for investigating complexes of fulvic acid and metal ions are presented. They

Robert A. Saar; James H. Weber

1982-01-01

137

Coprecipitation of alkali metal ions with calcium carbonate  

Microsoft Academic Search

The coprecipitation of alkali metal ions (Li + , Na + , K + and Rb + ) with calcium carbonate has been studied experimentally and the following results have been obtained: 1. (1) Alkali metal ions are more easily coprecipitated with aragonite than with calcite. 2. (2) The relationship between the amounts of alkali metal ions coprecipitated with aragonite

Minoru Okumura; Yasushi Kitano

1986-01-01

138

Chelation ion chromatography of trace metal ions using metallochromic ligands  

Microsoft Academic Search

Hydrophobic metallochromic ligands can be used to coat high-performance reversed-phase substrates producing chelating stationary phases with the capacity to separate metal ions. To date the main approaches have been to `pre-coat' the substrate with the ligand and use it with a mobile phase containing an inorganic salt or alternatively to include the ligand itself within the mobile phase, where the

Paul R Haddad

1999-01-01

139

Investigation of MEVVA ion source for metal ion injection into accelerators at GSI  

Microsoft Academic Search

High current metal ion production is a challenging task for ion source designers. The MEVVA ion source has proven to be a useful tool for accelerator injection and for ion implantation. We have investigated the MEVVA ion source in connection with the GSI heavy ion accelerators. At the Unilac accelerator as injector for the heavy ion Synchrotron SIS (1 Hz

B. H. Wolf; H. Emig

1994-01-01

140

Metal ion complexation by ionizable crown ethers  

SciTech Connect

Research conducted since the last progress report includes the synthesis and characterization of twenty three novel proton-ionizable crown ether compounds. Metal ion complexation behavior of new and previously-synthesized proton-ionizable crown ether compounds has been probed by solvent extraction and transport across polymer-supported liquid membranes. The behavior of neutral polyether and proton-ionizable polyether ligands in polymeric membrane electrodes has been assessed. Studies of the use of proton-ionizable crown ethers for separation of lithium isotopes were initiated. Also, the thermodynamics of interactions between alkali metal cations and ionized crown ethers have been probed by titration calorimetry. 10 refs., 1 tab.

Bartsch, R.A.

1989-09-01

141

Beta-delayed neutron spectroscopy using trapped radioactive ions  

NASA Astrophysics Data System (ADS)

The properties of beta-delayed neutron emission are of interest to both the basic and applied nuclear physics communities. For example, branching ratios are needed to determine how the short-lived neutron-rich isotopes synthesized in the astrophysical r process decay back to stability to become the isotopes we observe today. Also, neutron energy spectra and branching ratios are required for the design of nuclear reactors. Reliable measurements of the beta-delayed neutron properties can be performed with unprecedented precision using an ion trap surrounded by radiation detectors. When a radioactive ion decays in the trap, the recoil-daughter nucleus and emitted particles emerge from the ˜1 mm^3 trap volume with minimal scattering. These properties allow the momentum and energy of the emitted neutron to be precisely reconstructed from the nuclear recoil. Spectroscopy of beta-delayed neutrons can be performed with high efficiency, energy resolutions approaching ˜3%, and virtually no background. Results from a recent proof-of-principle experiment will be discussed. Prepared by LLNL under Contract DE-AC52-07NA27344 and ANL under Contract DE-AC02-06CH11357.

Yee, Ryan; Scielzo, N. D.; Bertone, P. F.; Buchinger, F.; Caldwell, S.; Clark, J. A.; Deibel, C. M.; Fallis, J.; Li, G.; Gulick, S.; Lascar, D.; Levand, A. F.; Norman, E. B.; Pedretti, M.; Savard, G.; Segel, R. E.; Sharma, K. S.; Sternberg, M. G.; van Schelt, J.; Zabransky, B. J.

2011-11-01

142

Status of GISELE: a resonant ionization laser ion source for the production of radioactive ions at GANIL  

NASA Astrophysics Data System (ADS)

Laser ion sources are in use extensively to ionize the nuclear reaction products at many on-line radioactive ion beam facilities. They have proven to be reliable and to combine good production efficiencies with chemical selectivity. A Laser ion source is currently under development for the SPIRAL2 project at GANIL. A status update of this project called GISELE is presented.

Sjödin, A. M.; Lecesne, N.; Bajeat, O.; Kron, T.; Lassen, J.; Le Blanc, F.; Leroy, R.; Maunoury, L.; Osmond, B.; Raeder, S.; Rothe, S.; Sonnenshein, V.; Wendt, K.

2013-04-01

143

IDENTIFICATION OF CATALYTIC METAL ION LIGANDS IN RIBOZYMES  

PubMed Central

Site-bound metal ions participate in the catalytic mechanisms of many ribozymes. Understanding these mechanisms therefore requires knowledge of the specific ligands on both substrate and ribozyme that coordinate these catalytic metal ions. A number of different structural and biochemical strategies have been developed and refined for identifying metal ion binding sites within ribozymes, and for assessing the catalytic contributions of the metal ions bound at those sites. We review these approaches and provide examples of their application, focusing in particular on metal ion rescue experiments and their roles in the construction of the transition state models for the Tetrahymena group I and RNase P ribozymes.

Frederiksen, John K.; Piccirilli, Joseph A.

2012-01-01

144

Effects of metal ion adduction on the gas-phase conformations of protein ions.  

PubMed

Changes in protein ion conformation as a result of nonspecific adduction of metal ions to the protein during electrospray ionization (ESI) from aqueous solutions were investigated using traveling wave ion mobility spectrometry (TWIMS). For all proteins examined, protein cations (and in most cases anions) with nonspecific metal ion adducts are more compact than the fully protonated (or deprotonated) ions with the same charge state. Compaction of protein cations upon nonspecific metal ion binding is most significant for intermediate charge state ions, and there is a greater reduction in collisional cross section with increasing number of metal ion adducts and increasing ion valency, consistent with an electrostatic interaction between the ions and the protein. Protein cations with the greatest number of adducted metal ions are no more compact than the lowest protonated ions formed from aqueous solutions. These results show that smaller collisional cross sections for metal-attached protein ions are not a good indicator of a specific metal-protein interaction in solution because nonspecific metal ion adduction also results in smaller gaseous protein cation cross sections. In contrast, the collisional cross section of ?-lactalbumin, which specifically binds one Ca(2+), is larger for the holo-form compared with the apo-form, in agreement with solution-phase measurements. Because compaction of protein cations occurs when metal ion adduction is nonspecific, elongation of a protein cation may be a more reliable indicator that a specific metal ion-protein interaction occurs in solution. PMID:23733259

Flick, Tawnya G; Merenbloom, Samuel I; Williams, Evan R

2013-06-04

145

Effects of Metal Ion Adduction on the Gas-Phase Conformations of Protein Ions  

NASA Astrophysics Data System (ADS)

Changes in protein ion conformation as a result of nonspecific adduction of metal ions to the protein during electrospray ionization (ESI) from aqueous solutions were investigated using traveling wave ion mobility spectrometry (TWIMS). For all proteins examined, protein cations (and in most cases anions) with nonspecific metal ion adducts are more compact than the fully protonated (or deprotonated) ions with the same charge state. Compaction of protein cations upon nonspecific metal ion binding is most significant for intermediate charge state ions, and there is a greater reduction in collisional cross section with increasing number of metal ion adducts and increasing ion valency, consistent with an electrostatic interaction between the ions and the protein. Protein cations with the greatest number of adducted metal ions are no more compact than the lowest protonated ions formed from aqueous solutions. These results show that smaller collisional cross sections for metal-attached protein ions are not a good indicator of a specific metal-protein interaction in solution because nonspecific metal ion adduction also results in smaller gaseous protein cation cross sections. In contrast, the collisional cross section of ?-lactalbumin, which specifically binds one Ca2+, is larger for the holo-form compared with the apo-form, in agreement with solution-phase measurements. Because compaction of protein cations occurs when metal ion adduction is nonspecific, elongation of a protein cation may be a more reliable indicator that a specific metal ion-protein interaction occurs in solution.

Flick, Tawnya G.; Merenbloom, Samuel I.; Williams, Evan R.

2013-06-01

146

Effects of Metal Ion Adduction on the Gas-Phase Conformations of Protein Ions  

NASA Astrophysics Data System (ADS)

Changes in protein ion conformation as a result of nonspecific adduction of metal ions to the protein during electrospray ionization (ESI) from aqueous solutions were investigated using traveling wave ion mobility spectrometry (TWIMS). For all proteins examined, protein cations (and in most cases anions) with nonspecific metal ion adducts are more compact than the fully protonated (or deprotonated) ions with the same charge state. Compaction of protein cations upon nonspecific metal ion binding is most significant for intermediate charge state ions, and there is a greater reduction in collisional cross section with increasing number of metal ion adducts and increasing ion valency, consistent with an electrostatic interaction between the ions and the protein. Protein cations with the greatest number of adducted metal ions are no more compact than the lowest protonated ions formed from aqueous solutions. These results show that smaller collisional cross sections for metal-attached protein ions are not a good indicator of a specific metal-protein interaction in solution because nonspecific metal ion adduction also results in smaller gaseous protein cation cross sections. In contrast, the collisional cross section of ?-lactalbumin, which specifically binds one Ca2+, is larger for the holo-form compared with the apo-form, in agreement with solution-phase measurements. Because compaction of protein cations occurs when metal ion adduction is nonspecific, elongation of a protein cation may be a more reliable indicator that a specific metal ion-protein interaction occurs in solution.

Flick, Tawnya G.; Merenbloom, Samuel I.; Williams, Evan R.

2013-11-01

147

On the Metal Ion Selectivity of Oxoacid Extractants  

SciTech Connect

Relationships between metal chelate stability, ligand basicity, and metal ion acidity are reviewed and the general applicability is illustrated by linear correlations between aqueous stability constants and ligand pKa values for 35 metals with 26 ligands. The results confirm that most individual ligands of this type exhibit a stability ordering that correlates with the Lewis acidity of the metal ion. It is concluded that the general metal ion selectivity exhibited by liquid-liquid oxoacid extractants such as carboxylic acids, -diketones, and alkylphosphoric acids reflects the intrinsic affinity of the metal ion for the negative oxygen donor ligand.

Hay, Benjamin [ORNL; Chagnes, Alexandre [Chimie ParisTech; Cote, Gerard [Chimie ParisTech

2013-01-01

148

Upgrade status and plans at the Holifield Radioactive Ion Beam Facility  

Microsoft Academic Search

The Holifield Radioactive Ion Beam Facility (HRIBF) is a national user facility dedicated to nuclear structure and astrophysics research with Radioactive Ion Beams (RIBs) using the Isotope Separator On-Line (ISOL) technique. HRIBF also maintains a vibrant development program for ISOL targets, ion sources and diagnostics. As a bridge to RIA, HRIBF continues to expand its technology. Presently, a $4.75M High

Brian Alan Tatum

2005-01-01

149

Oxidation-reduction reactions of metal ions.  

PubMed Central

Several metal or metalloid ions exist in multiple oxidation states and can undergo electron transfer reactions that are important in biological and environmental systems. There are endogenous metal ions such as iron, copper, and cobalt that participate in oxidation-reduction reactions with species of oxygen like molecular dioxygen, superoxide, and hydrogen peroxide. These reactions may be modulated by endogenous reducing agents such as glutathione, ascorbate, and tocopherol. The reactions can be described in terms of thermodynamics through the use of standard electrode potentials. A favorable reaction will depend on the concentrations of the reactants and may depend on the pH and/or on the presence of organic ligands that form complexes with the metal or metalloid. Arsenate (As(V)) can react with glutathione in buffered aqueous solutions to produce arsenite (As(III)) and oxidized glutathione. This reaction may be important in the methylation reactions of arsenic. Arsenic species can decrease the red blood cell levels of reduced glutathione, but the products of oxidation and the mechanism of oxidation are more complex than those found in water alone. Chromium (VI) is thought to interact with DNA after first reacting with a reducing agent such as glutathione to form lower oxidation states of chromium. These examples illustrate the importance of oxidation-reduction reactions for toxic metals and metalloids.

Carter, D E

1995-01-01

150

Analysis of metallic pigments by ion microbeam  

NASA Astrophysics Data System (ADS)

Metallic paints consist of metallic flakes dispersed in a resinous binder, i.e. a light-element polymer matrix. The spatial distribution and orientation of metallic flakes inside the matrix determines the covering efficiency of the paint, glossiness, and its angular-dependent properties such as lightness flop or color flop (two-tone). Such coatings are extensively used for a functional (i.e. security) as well as decorative purpose. The ion microbeam analysis of two types of silver paint with imbedded metallic flakes has been performed to determine the spatial distribution of the aluminum flakes in paint layer. The average sizes of the aluminum flakes were 23 /?m (size distribution 10-37) and 49 /?m (size distribution 34-75), respectively. The proton beam with the size of /2×2 /?m2 at Ljubljana ion microprobe has been used to scan the surface of the pigments. PIXE mapping of AlK/? map shows lateral distribution of the aluminum flakes, whereas the RBS slicing method reveals tomograms of the flakes in uppermost 7 /?m of the pigment layer. The series of point analysis aligned over the single flake reveal the flake angle in respect to the polymer matrix surface. The angular sensitivity is well below 1 angular degree.

Pelicon, P.; Klanjšek-Gunde, M.; Kunaver, M.; Sim?i?, J.; Budnar, M.

2002-05-01

151

Charge breeding of isotope on-line-created radioactive ions using an electron cyclotron resonance ion trap  

NASA Astrophysics Data System (ADS)

In the coming years huge ion-beam projects are foreseen. They deal with specific isotope on-line (ISOL) beams such as ISOL-created radioactive ions. The beam intensities are exceptionally high (>1012 ions/s), the radioactive lifetimes are short (<=1 s), and the ion energy is very high (>=150 GeV/u). In general in order to minimize the size of the accelerator one needs highly charged ISOL ions and therefore charge breeders are a must. In contrast with the CERN system, utilizing a Penning trap and an electron-beam ion source charge breeder (where the maximum ion beam cannot exceed 106 ions/s) the Grenoble group launched in 1995 an electron cyclotron resonance (ECR) system capable of storing 1012 ions/s and delivering highly charged ISOL ions. In this article we show that this storage is possible for low-ion-energy ISOL ions following classical slowing down theory. In this case the injected ISOL ions are slowed down by ion-ion collisions which yield ion storage inside the ECR plasma, but also charge breeding by the energetic ECR electrons bombarding the slowed down ions.

Geller, R.; Lamy, T.; Sortais, P.

2006-03-01

152

Liquid metal alloy ion source based metal ion injection into a room-temperature electron beam ion source  

SciTech Connect

We have carried out a series of measurements demonstrating the feasibility of using the Dresden electron beam ion source (EBIS)-A, a table-top sized, permanent magnet technology based electron beam ion source, as a charge breeder. Low charged gold ions from an AuGe liquid metal alloy ion source were injected into the EBIS and re-extracted as highly charged ions, thereby producing charge states as high as Au{sup 60+}. The setup, the charge breeding technique, breeding efficiencies as well as acceptance and emittance studies are presented.

Thorn, A.; Ritter, E.; Zschornack, G. [Fachrichtung Physik, Technische Universitaet Dresden, Helmholtzstrasse 10, D-01069 Dresden (Germany); Ullmann, F. [DREEBIT GmbH, Zur Wetterwarte 50, D-01109 Dresden (Germany); Pilz, W.; Bischoff, L. [Helmholtzzentrum Dresden-Rossendorf, Bautzner Landstrasse 400, D-01328 Dresden (Germany)

2012-02-15

153

Ion species measurement of high current metal ion beams extracted from a multicusp ion source  

Microsoft Academic Search

Ion charge state and impurities extracted from a multicusp ion source have been studied with the use of a magnetic momentum mass analyzer. Impurities contained in high current metal ion beams are crucible materials (such as Al2O3, BN, Y2O3, C) and high melting point materials (such as Mo, Ta, W). To reduce these impurities, the dependence of the impurity on

Yasuhiro Matsuda; Hiroshi Inami; Takatoshi Yamashita; Shuichi Fujiwara; Yutaka Inouchi; Kouzi Matsunaga; Koji Matsuda

1992-01-01

154

[Metal ion concentrations in patients with metal-metal bearings in prostheses].  

PubMed

Increased wear leads to elevated systemic and local metal ion concentrations for patients treated with metal-on-metal bearings. The local metal ion content in the close environment of the joint replacement (e.g. joint aspirate or tissue) is several times higher compared to the systemic metal content (e.g. in blood or serum). As a result of increased metal ion levels, local and systemic effects, such as osteolysis, pseudotumors, sensitization or in rare cases toxicity may occur. Although the definition of a specific threshold to define clinical problems is difficult due to a lack of sensitivity, the systemic metal concentration is frequently measured clinically. Currently a threshold for cobalt and chromium between 4 µg/l and 7 µg/l is under debate. Very high levels (??20 µg/l) or a steady increase over time should be a warning sign; however, metal ion levels should not be interpreted as a single diagnostic tool but rather in the entire context of the clinical, radiological and cross-sectional imaging, metal artefact reduction sequence (MARS) magnetic resonance imaging (MRI), ultrasound and computed tomography (CT) findings. PMID:23842780

Kretzer, J P; Van Der Straeten, C; Sonntag, R; Müller, U; Streit, M; Moradi, B; Jäger, S; Reinders, J

2013-08-01

155

Direct reaction measurements with a (132)Sn radioactive ion beam  

SciTech Connect

The (d,p) neutron transfer and (d,d) elastic scattering reactions were measured in inverse kinematics using a radioactive ion beam of {sup 132}Sn at 630 MeV. The elastic scattering data were taken in a region where Rutherford scattering dominated the reaction, and nuclear effects account for less than 8% of the elastic scattering cross section. The magnitude of the nuclear effects, in the angular range studied, was found to be independent of the optical potential used, allowing the transfer data to be normalized in a reliable manner. The neutron-transfer reaction populated a previously unmeasured state at 1363 keV, which is most likely the single-particle 3p{sub 1/2} state expected above the N=82 shell closure. The data were analyzed using finite-range adiabatic-wave calculations and the results compared with the previous analysis using the distorted-wave Born approximation. Angular distributions for the ground and first-excited states are consistent with the previous tentative spin and parity assignments. Spectroscopic factors extracted from the differential cross sections are similar to those found for the one-neutron states beyond the benchmark doubly magic nucleus {sup 208}Pb.

Jones, K. L. [University of Tennessee, Knoxville (UTK); Chae, K. Y. [University of Tennessee, Knoxville (UTK); Kapler, R. [University of Tennessee, Knoxville (UTK); Ma, Zhanwen [ORNL; Moazen, Brian [University of Tennessee, Knoxville (UTK); Cizewski, J. A. [Rutgers University; Hatarik, Robert [Rutgers University; Pain, S. D. [Rutgers University; Swan, T. P. [University of Surrey, UK; Nunes, F. M. [Michigan State University, East Lansing; Adekola, Aderemi S [ORNL; Bardayan, Daniel W [ORNL; Blackmon, Jeff C [ORNL; Chae, Kyung Yuk [ORNL; Liang, J Felix [ORNL; Nesaraja, Caroline D [ORNL; Pain, Steven D [ORNL; Shapira, Dan [ORNL; Smith, Michael Scott [ORNL; Chipps, Kelly A [ORNL; Erikson, Luke [Colorado School of Mines, Golden; Livesay, R. J. [Colorado School of Mines, Golden; Harlin, Christopher W [ORNL; Patterson, N. P. [University of Surrey, UK; Thomas, J. S. [University of Surrey, England; Kozub, R. L. [Tennessee Technological University; Shriner, Jr., John F [ORNL

2011-01-01

156

Direct reaction measurements with a 132Sn radioactive ion beam  

SciTech Connect

The (d,p) neutron transfer and (d,d) elastic scattering reactions were measured in inverse kinematics using a radioactive ion beam of 132Sn at 630 MeV. The elastic scattering data were taken in a region where Rutherford scattering dominated the reaction, and nuclear effects account for less than 8% of the elastic scattering cross section. The magnitude of the nuclear effects, in the angular range studied, was found to be independent of the optical potential used, allowing the transfer data to be normalized in a reliable manner. The neutron-transfer reaction populated a previously unmeasured state at 1363 keV, which is most likely the single-particle 3p1/2 state expected above the N = 82 shell closure. The data were analyzed using finite-range adiabatic-wave calculations and the results compared with the previous analysis using the distorted-wave Born approximation. Angular distributions for the ground and first-excited states are consistent with the previous tentative spin and parity assignments. Spectroscopic factors extracted from the differential cross sections are similar to those found for the one-neutron states beyond the benchmark doubly magic nucleus 208Pb.

Jones, Katherine L.; Nunes, Filomena M.; Adekola, Aderemi S.; Bardayan, Dan W.; Blackmon, Jeff; Chae, K. Y.; Chipps, Kelly A.; Cizewski, Jolie A.; Erikson, Luke E.; Harlin, C.; Hatarik, R.; Kapler, R.; Kozub, Raymond L.; Liang, J. F.; Livesay, Ronald J.; Ma, Zhongguo J.; Moazen, B. H.; Nesaraja, Caroline D.; Pain, Steven D.; Patterson, N. P.; Shapira, Dan; Shriner, Jr., John F.; Smith, Michael S.; Swan, Thomas P.; Thomas, Jeff S.

2011-09-01

157

A Gas Jet Target for Radioactive Ion Beam Experiments  

NASA Astrophysics Data System (ADS)

With the development of new radioactive ion beam (RIB) facilities such as FRIB, which will push further away from stability, the need for improved RIB targets is more crucial than ever. Important scattering, transfer and capture reaction measurements of rare, exotic, and unstable nuclei on hydrogen and helium require targets that are dense (˜1x10^19 nuclei/cm^2), highly localized, and pure. Conventional targets suffer too many drawbacks to allow for such measurements. Targets must also accommodate the use of novel detector arrays. To this end, a collaboration led by the Colorado School of Mines (CSM) is designing, building and testing a supersonic gas jet target for use at existing and future RIB facilities. The gas jet target allows for a high density and purity of target nuclei (such as ^3He) within a highly confined region, without the use of windows or backing materials, and will also enable the use of state-of-the-art detection systems. Motivation, specifications and status of the CSM gas jet target system will be discussed.

Chipps, K. A.

2011-10-01

158

Towards liquid metal ion source chips: Indium liquid metal ion source with glass microcapillaries  

NASA Astrophysics Data System (ADS)

A liquid-metal-ion-source with indium propellant using an uncoated fused quartz glass microcapillary was manufactured and tested. The extremely thin capillary enabled a very low ignition voltage of 1000 V and a high electrical impedance ideal for clustering. However, low bonding forces between indium and glass resulted in a rather short lifetime of little more than 10 min. The use of pure glass as emitter material may enable liquid ion source chips with high current densities in the future.

Tajmar, M.; Plesescu, F.

2013-01-01

159

Substrate profile and metal-ion selectivity of human divalent metal-ion transporter-1.  

PubMed

Divalent metal-ion transporter-1 (DMT1) is a H(+)-coupled metal-ion transporter that plays essential roles in iron homeostasis. DMT1 exhibits reactivity (based on evoked currents) with a broad range of metal ions; however, direct measurement of transport is lacking for many of its potential substrates. We performed a comprehensive substrate-profile analysis for human DMT1 expressed in RNA-injected Xenopus oocytes by using radiotracer assays and the continuous measurement of transport by fluorescence with the metal-sensitive PhenGreen SK fluorophore. We provide validation for the use of PhenGreen SK fluorescence quenching as a reporter of cellular metal-ion uptake. We determined metal-ion selectivity under fixed conditions using the voltage clamp. Radiotracer and continuous measurement of transport by fluorescence assays revealed that DMT1 mediates the transport of several metal ions that were ranked in selectivity by using the ratio I(max)/K(0.5) (determined from evoked currents at -70 mV): Cd(2+) > Fe(2+) > Co(2+), Mn(2+) ? Zn(2+), Ni(2+), VO(2+). DMT1 expression did not stimulate the transport of Cr(2+), Cr(3+), Cu(+), Cu(2+), Fe(3+), Ga(3+), Hg(2+), or VO(+). (55)Fe(2+) transport was competitively inhibited by Co(2+) and Mn(2+). Zn(2+) only weakly inhibited (55)Fe(2+) transport. Our data reveal that DMT1 selects Fe(2+) over its other physiological substrates and provides a basis for predicting the contribution of DMT1 to intestinal, nasal, and pulmonary absorption of metal ions and their cellular uptake in other tissues. Whereas DMT1 is a likely route of entry for the toxic heavy metal cadmium, and may serve the metabolism of cobalt, manganese, and vanadium, we predict that DMT1 should contribute little if at all to the absorption or uptake of zinc. The conclusion in previous reports that copper is a substrate of DMT1 is not supported. PMID:22736759

Illing, Anthony C; Shawki, Ali; Cunningham, Christopher L; Mackenzie, Bryan

2012-06-26

160

Ion beam superpolishing of metal mirrors for high energy lasers  

Microsoft Academic Search

A new process has been developed which employs a low energy ion beam to superpolish metal surfaces. The process is applicable in principle to all metals. This technique overcomes the tendency of metal surfaces to develop etch patterns and other surface irregularities during ion beam bombardment. The process produces superpolished optical surfaces significantly superior to those formed by conventional optical

J. D. Lester; H. Gelles; R. T. Cook

1975-01-01

161

Metal-ion rescue revisited: biochemical detection of site-bound metal ions important for RNA folding.  

PubMed

Within the three-dimensional architectures of RNA molecules, divalent metal ions populate specific locations, shedding their water molecules to form chelates. These interactions help the RNA adopt and maintain specific conformations and frequently make essential contributions to function. Defining the locations of these site-bound metal ions remains challenging despite the growing database of RNA structures. Metal-ion rescue experiments have provided a powerful approach to identify and distinguish catalytic metal ions within RNA active sites, but the ability of such experiments to identify metal ions that contribute to tertiary structure acquisition and structural stability is less developed and has been challenged. Herein, we use the well-defined P4-P6 RNA domain of the Tetrahymena group I intron to reevaluate prior evidence against the discriminatory power of metal-ion rescue experiments and to advance thermodynamic descriptions necessary for interpreting these experiments. The approach successfully identifies ligands within the RNA that occupy the inner coordination sphere of divalent metal ions and distinguishes them from ligands that occupy the outer coordination sphere. Our results underscore the importance of obtaining complete folding isotherms and establishing and evaluating thermodynamic models in order to draw conclusions from metal-ion rescue experiments. These results establish metal-ion rescue as a rigorous tool for identifying and dissecting energetically important metal-ion interactions in RNAs that are noncatalytic but critical for RNA tertiary structure. PMID:22539523

Frederiksen, John K; Li, Nan-Sheng; Das, Rhiju; Herschlag, Daniel; Piccirilli, Joseph A

2012-04-26

162

The radioactive ion beam facility at VECC Calcutta - a status report  

NASA Astrophysics Data System (ADS)

The proposal to build a low-energy radioactive ion beam (RIB) facility at VEC Centre, Calcutta, has recently been approved. A brief description of this facility and the present status of various components of this system will be discussed.

Chakrabarti, Alok

1998-08-01

163

Silica-Polyamine Composite Materials for Heavy Metal Ion Removal, Recovery, and Recycling. II. Metal Ion Separations from Mine Wastewater and Soft Metal Ion Extraction Efficiency  

Microsoft Academic Search

Silica-polyamine composites have been synthesized which have metal ion capacities as high as 0.84 mmol\\/g for copper ions removed from aqueous solutions. In previous reports it has been demonstrated that these materials survive more than 3000 cycles of metal ion extraction, elution, and regeneration with almost no loss of capacity (less than 10%). This paper describes two modified silica-polyamine composite

ROBERT J. FISCHER; DAVID PANG; SUSAN T. BEATTY; EDWARD ROSENBERG

1999-01-01

164

Radioactive Ion Beams with the HHIRF (Holifield Heavy Ion Research Facility) accelerators  

SciTech Connect

Our present understanding of nuclear structure is almost completely based on facts obtained for nuclei that can be produced with stable projectiles and targets which have equilibrated for a significant fraction of the lifetime of the universe. The use of Radioactive Ion Beams (RIB) could overcome this limitation and provide unique opportunities for the study of nuclear structure with nuclei far from stability. These nuclei could answer critical issues concerning some of the most fundamental current nuclear structure themes and allow the study of entirely new phenomena, unobservable with current techniques and not derivable from our present knowledge of nuclear theory. RIB will also open new opportunities for the study of processes taking place at less equilibrated astrophysical sites, such as supernovae, cataclysmic binaries, and accreted shells of neutron stars. Widespread interest in RIB has developed in the last few years and a steering committee has recently been established to consider the construction of a large radioactive beam facility in North America. With this interest in mind, we have performed a feasibility study for a low-cost extension of the Holifield Heavy Ion Research Facility (HHIRF) accelerators which would provide access, on a short time scale, to much of the physics of proton-rich nuclei.

Meigs, M.J.; Alton, G.D.; Baktash, C.; Dowling, D.T.; Garrett, J.D.; Haynes, D.L.; Jones, C.M.; Juras, R.C.; Lane, S.N.; Lee, I.Y.; Mills, G.D.; Mosko, S.W.; Olsen, D.K.; Tatum, B.A.; Toth, K.S. (Oak Ridge National Lab., TN (USA)); Carter, H.K. (Oak Ridge Associated Universities, Inc., TN (USA))

1990-01-01

165

The NRAMP family of metal-ion transporters.  

PubMed

The family of NRAMP metal ion transporters functions in diverse organisms from bacteria to human. NRAMP1 functions in metal transport across the phagosomal membrane of macrophages, and defective NRAMP1 causes sensitivity to several intracellular pathogens. DCT1 (NRAMP2) transport metal ions at the plasma membrane of cells of both the duodenum and in peripheral tissues, and defective DCT1 cause anemia. The driving force for the metal-ion transport is proton gradient (protonmotive force). In DCT1 the stoichiometry between metal ion and proton varied at different conditions due to a mechanistic proton slip. Though the metal ion transport by Smf1p, the yeast homolog of DCT1, is also a protonmotive force, a slippage of sodium ions was observed. The mechanism of the above phenomena could be explained by a combination between transporter and channel mechanisms. PMID:16908340

Nevo, Yaniv; Nelson, Nathan

2006-05-19

166

Direct 1{sup +} to n{sup +} method for production of radioactive alkaline ions  

SciTech Connect

In the frame of the production of radioactive ion beams by isotope separator on line method, a new principle of target/ion-source system has been developed at GANIL to produce multicharged ions of alkalis. The principle consists of a surface ionization source associated to a multicharged electron-cyclotron-resonance ion source (ECRIS) named NANOGAN III [R. Leroy et al., AIP Conf. Proc. 749, 137 (2004)] presently used to produce radioactive ions of gas on Systeme de Production d'Ions Radioactifs Acceleres en Ligne partie I. The singly charged ions are injected in the multicharged ion source without mass separation, through a very short beam line including several stages of acceleration, focusing, deceleration, and rf injection. The first tests showed a good behavior of the ECRIS with the new rf coupling. A study of the surface ionization source is in progress in order to improve its coupling to the 1{sup +} beam line.

Eleon, C.; Tuske, O.; Gaubert, G.; Pacquet, J. Y.; Dubois, M.; Saint Laurent, M.G.; Jardin, P.; Cornell, J.; Leroy, R.; Villari, A.C.C.; Maunoury, L. [Grand Accelerateur National d'Ions Lourds (GANIL), Bd Henri Becquerel, B.P. 55027, 14076 Caen Cedex 5 (France); CEA Bruyeres le Chatel, B.P. 12, 91680 Bruyeres le Chatel (France); Grand Accelerateur National d'Ions Lourds (GANIL), Bd Henry Becquerel, B.P. 55027, 14076 Caen Cedex 5 (France)

2006-03-15

167

Photoluminescent graphene oxide microarray for multiplex heavy metal ion analysis.  

PubMed

An aptamer-linked graphene oxide (GO) microarray is synthesized for multiplex heavy metal ion detection. Fluorescent nanosized GO sheets are micropatterned, and specific aptamers targeting Ag(+) and Hg(2+) are immobilized on the GO array. Upon capture of the target heavy metal ions, electron transfer occurs between the GO (donors) and the heavy metal ions (acceptors), leading to fluorescence quenching of the GO. PMID:23606642

Liu, Fei; Ha, Hyun Dong; Han, Dong Ju; Seo, Tae Seok

2013-04-19

168

Determination of metal ions using ion chromatography and indirect amperometric detection  

SciTech Connect

A method for determination of metal ions subsequent to ion chromatographic separation has been devised. The method is based on indirect amperometric detection whereby a decrease in an oxidation current, proportional to the concentration of metal ion, is monitored. In this particular work, an easily oxidized ligand is added postcolumn. Upon complexation with the metal ions, the ligand is rendered electroinactive at the preselected potential. The fact that the ligand is oxidized at low anodic potentials results in a selective detection system.

Hojabri, H.; Lavin, A.G.; Wallace, G.G.; Riviello, J.M.

1987-01-01

169

Securing the metal recycling chain for the steel industry by detecting orphan radioactive sources in scrap metal  

SciTech Connect

Experimental tests are reported for the detection of the heavy metal shielding of orphan sources hidden inside scrap metal by using a recently developed muon tomography system. Shielded sources do not trigger alarm in radiation portal commonly employed at the entrance of steel industry using scrap metal. Future systems integrating radiation portals with muon tomography inspection gates will substantially reduce the possibility of accidental melting of radioactive sources securing the use of recycled metal.

Pesente, S.; Benettoni, M.; Checchia, P.; Conti, E.; Gonella, F.; Nebbia, G. [INFN Sezione di Padova, via Marzolo 8, 35131 Padova Italy (Italy); Vanini, S.; Viesti, G.; Zumerle, G. [INFN Sezione di Padova, via Marzolo 8, 35131 Padova Italy (Italy); University of Padova and INFN Sezione di Padova, via Marzolo 8, 35131 Padova Italy (Italy); Bonomi, G.; Zenoni, A. [University of Brescia, via Branze 38, 25123 Brescia and INFN Sezione di Pavia, via Bassi 6, 27100 Pavia (Italy); Calvini, P.; Squarcia, S. [University of Genova and INFN Sezione di Genova, via Dodecaneso 33, 16146 Genova (Italy)

2010-08-04

170

Calmodulin inhibition: a possible predictor of metal-ion toxicity  

SciTech Connect

A correlation between CE/sub 50/, the metal-ion concentration which reduces the cloning efficiency of CHO cells by 50%, and IC/sub 50/, the metal-ion concentration that produces an inhibition of calmodulin activity of 50%, is reported for 10 divalent metal ions. It is thus suggested that IC/sub 50/ might be used as a predictor of metal-ion toxicity in CHO cells. Arguments are presented to support the extrapolation of these results to other pollutants and to other biological species.

Williams, M.W.; Turner, J.E.; Hsie, A.W.

1986-01-01

171

Plasma immersion ion implantation for reducing metal ion release  

NASA Astrophysics Data System (ADS)

Plasma immersion ion implantation of Nitrogen and Oxygen on CoCrMo alloys was carried out to improve the tribological and corrosion behaviors of these biomedical alloys. In order to optimize the implantation results we were carried experiments at different temperatures. Tribocorrosion tests in bovine serum were used to measure Co, Cr and Mo releasing by using Inductively Coupled Plasma Mass Spectrometry analysis after tests. Also, X-ray Diffraction analysis were employed in order to explain any obtained difference in wear rate and corrosion tests. Wear tests reveals important decreases in rate of more than one order of magnitude for the best treatment. Moreover decreases in metal release were found for all the implanted samples, preserving the same corrosion resistance of the unimplanted samples. Finally this paper gathers an analysis, in terms of implantation parameters and achieved properties for industrial implementation of these treatments.

Díaz, C.; García, J. A.; Mändl, S.; Pereiro, R.; Fernández, B.; Rodríguez, R. J.

2012-11-01

172

Plasma immersion ion implantation for reducing metal ion release  

SciTech Connect

Plasma immersion ion implantation of Nitrogen and Oxygen on CoCrMo alloys was carried out to improve the tribological and corrosion behaviors of these biomedical alloys. In order to optimize the implantation results we were carried experiments at different temperatures. Tribocorrosion tests in bovine serum were used to measure Co, Cr and Mo releasing by using Inductively Coupled Plasma Mass Spectrometry analysis after tests. Also, X-ray Diffraction analysis were employed in order to explain any obtained difference in wear rate and corrosion tests. Wear tests reveals important decreases in rate of more than one order of magnitude for the best treatment. Moreover decreases in metal release were found for all the implanted samples, preserving the same corrosion resistance of the unimplanted samples. Finally this paper gathers an analysis, in terms of implantation parameters and achieved properties for industrial implementation of these treatments.

Diaz, C.; Garcia, J. A.; Maendl, S.; Pereiro, R.; Fernandez, B.; Rodriguez, R. J. [Centro de Ingenieria Avanzada de Superficies AIN, 31191, Cordovilla-Pamplona (Spain); Leibniz-Institut fuer Oberflaechenmodifizierung, 04318 Leipzig (Germany); Universidad de Oviedo, Departamento Quimica Fisica y Analitica (Spain); Centro de Ingenieria Avanzada de Superficies AIN, 31191, Cordovilla-Pamplona (Spain)

2012-11-06

173

The ion exchange properties of low rank coals on actinides and other heavy metals  

SciTech Connect

The removal of heavy metal and low-level radioactive wastes from the environment and their subsequent immobilization in an appropriate repository is one of the major environmental challenges facing our nation. The scope and magnitude of the contamination at many DOE and Superfund sites are such that successful remediation will require the development of new, inexpensive technologies which remove, in an environmentally acceptable manner, the heavy metal and radioactive wastes from contaminated soil and water. In this paper, we will present the preliminary data on the viability of using low rank coals or lignites as a novel, inexpensive material to remove actinides and other metals from the aqueous system, and the effects of high radiation on ion-exchange properties of lignites.

Wong, A.S.; Stalnaker, N.D. [Los Alamos National Lab., NM (United States); Lafferty, C.J. [Univ. of Kentucky, Lexington, KY (United States)] [and others

1996-12-31

174

Conformational thermodynamics of metal-ion binding to a protein  

NASA Astrophysics Data System (ADS)

Conformational changes in proteins induced by metal-ions play extremely important role in various cellular processes and technological applications. Dihedral angles are suitable conformational variables to describe microscopic conformations of a biomacromolecule. Here, we use the histograms of the dihedral angles to study the thermodynamics of conformational changes of a protein upon metal-ion binding. Our method applied to Ca2+ ion binding to an important metalloprotein, Calmodulin, reveals different thermodynamic changes in different metal-binding sites. The ligands coordinating to Ca2+ ions also play different roles in stabilizing the metal-ion coordinated protein-structure. Metal-ion binding induce remarkable thermodynamic changes in distant part of the protein via modification of secondary structural elements.

Das, Amit; Chakrabarti, J.; Ghosh, Mahua

2013-08-01

175

A biosystem for removal of metal ions from water  

SciTech Connect

The presence of heavy metal ions in ground and surface waters constitutes a potential health risk and is an environmental concern. Moreover, processes for the recovery of valuable metal ions are of interest. Bioaccumulation or biosorption is not only a factor in assessing the environmental risk posed by metal ions; it can also be used as a means of decontamination. A biological system for the removal and recovery of metal ions from contaminated water is reported here. Exopolysaccharide-producing microorganisms, including a methanotrophic culture, are demonstrated to have superior metal binding ability, compared with other microbial cultures. This paper describes a biosorption process in which dried biomass obtained from exopolysaccharide-producing microorganisms is encapsulated in porous plastic beads and is used for metal ion binding and recovery. 22 refs., 13 figs.

Kilbane, J.J. II.

1990-01-01

176

Nuclear astrophysics and the Daresbury Recoil Separator at the Holifield Radioactive Ion Beam Facility  

SciTech Connect

The Daresbury Recoil Separator (DRS) has been installed for nuclear astrophysics research at Oak Ridge National Laboratory`s Holifield Radioactive Ion Beam Facility. It will be used for direct measurements of capture reactions on radioactive ions which occur in stellar explosions such as novae, supernovae and X-ray bursts. These measurements will be made in inverse kinematics with radioactive heavy ion beams incident on hydrogen and helium targets, and the DRS will separate the capture reaction recoils from the intense flux of beam particles. Details of the new DRS experimental equipment and preliminary results from the first commissioning experiments with stable beams are described, along with the plans for the first measurements with radioactive beams. Other astrophysics research efforts at ORNL--in theoretical astrophysics, nuclear astrophysics data evaluation, heavy element nucleosynthesis, theoretical atomic astrophysics, and atomic astrophysics data--are also briefly described.

Smith, M.S.

1997-12-01

177

The extension of the HHIRF accelerators to produce radioactive ion beams  

SciTech Connect

The production of medium-intensity, proton-rich, radioactive ion beams for nuclear physics, astrophysics, and applied research with the HHIRF accelerators is discussed. Radioactive atoms will be produced with fusion reactions by light-ion beams from the K = 105 Oak Ridge Isochronous Cyclotron stopping in an ISOLDE-type thick target mounted on a 300-kV high-voltage platform. These radioactive atoms will be ionized, mass separated, and charge exchanged to negative ions on the high-voltage platform prior to injection into the HHIRF 25-MV tandem accelerator. Beams of up to mass 80 will be accelerated to energies greater than 5 MeV/nucleon. For some radioactive beams, intensities greater than 1 pnA can be expected. 7 refs., 1 fig., 1 tab.

Olsen, D.K.; Alton, G.D.; Baktash, C.; Dowling, D.T.; Garrett, J.D.; Haynes, D.L.; Jones, C.M.; Juras, R.C.; Lane, S.N.; Lee, I.Y.; Meigs, M.J.; Mills, G.D.; Mosko, S.W.; Tatum, B.A.; Toth, K.S. (Oak Ridge National Lab., TN (United States)); Carter, H.K. (Oak Ridge Associated Universities, Inc., TN (United States))

1991-01-01

178

METAL ION COORDINATION STUDIES ON A SILICA-BASED ION EXCHANGE RESIN BEFORE AND AFTER HEATING  

Microsoft Academic Search

Work designed to assess the potential of using a single material to sorb highly charged metal ions from aqueous solution and then microencapsulate and chemical fix those sorbed metal ions in vitreous silica is described. The basis for these studies is a chemically functionalized porous silica that is termed Diphosil. Diphosil was created by Chiarizia and coworkers (Solv. Extr. Ion

James V. Beitz; Clayton W. Williams

2001-01-01

179

Insight into the mechanisms of metal ion binding in hexagonal tungsten bronze  

NASA Astrophysics Data System (ADS)

Tungsten trioxides and their alkali-metal-intercalated products MzWO3+ show potential for application in electrodes, as ion exchangers, catalysts and the treatment of radioactive waste. Hexagonal tungsten bronze (HTB) was selected for the present work because its structure features hexagonal channels, of diameter ˜0.54 nm, that may be useful for selective and reversible binding of metal ions. X-ray and neutron powder diffraction were used to provide an insight into the mechanisms of metal ion binding of the Mo doped HTB's. Combined Rietveld refinement of the X-ray and neutron diffraction shows that doping with Mo degrades the crystallinity of HTB, in particular by creating a high degree of disorder in the a-b planes. Structural information combined with solution chemistry indicates several potential mechanisms of binding and metal ion exchange sites. This type of investigation provides invaluable information for new strategies in the design of inorganic sorbents and their optimization for metal ion separation.

Kennedy, Shane; Smith, Suzanne; Avdeev, Maxim; Fuchs, Alex

2006-03-01

180

On the retention of uranyl and thorium ions from radioactive solution on peat moss  

Microsoft Academic Search

The efficiency of the radioactive uranyl and thorium ions on the peat moss from aqueous solutions has been investigated under different experimental conditions. The sorption and desorption of uranyl and thorium ions on three types (unmodified peat moss, peat moss treated with HNO3 and peat moss treated with NaOH) of peat moss were studied by the static method. Peat moss

Doina Humelnicu; Laura Bulgariu; Matei Macoveanu

2010-01-01

181

Calmodulin Inhibition: A Possible Predictor of Metal-Ion Toxicity.  

National Technical Information Service (NTIS)

A correlation between CE sub 50 , the metal-ion concentration which reduces the cloning efficiency of CHO cells by 50%, and IC sub 50 , the metal-ion concentration that produces an inhibition of calmodulin activity of 50%, is reported for 10 divalent meta...

M. W. Williams J. E. Turner A. W. Hsie

1986-01-01

182

Electron Capture Dissociation of Trivalent Metal Ion-Peptide Complexes  

NASA Astrophysics Data System (ADS)

With electrospray ionization from aqueous solutions, trivalent metal ions readily adduct to small peptides resulting in formation of predominantly (peptide + MT - H)2+, where MT = La, Tm, Lu, Sm, Ho, Yb, Pm, Tb, or Eu, for peptides with molecular weights below ~1000 Da, and predominantly (peptide + MT)3+ for larger peptides. ECD of (peptide + MT - H)2+ results in extensive fragmentation from which nearly complete sequence information can be obtained, even for peptides for which only singly protonated ions are formed in the absence of the metal ions. ECD of these doubly charged complexes containing MT results in significantly higher electron capture efficiency and sequence coverage than peptide-divalent metal ion complexes that have the same net charge. Formation of salt-bridge structures in which the metal ion coordinates to a carboxylate group are favored even for (peptide + MT)3+. ECD of these latter complexes for large peptides results in electron capture by the protonation site located remotely from the metal ion and predominantly c/ z fragments for all metals, except Eu3+, which undergoes a one electron reduction and only loss of small neutral molecules and b/ y fragments are formed. These results indicate that solvation of the metal ion in these complexes is extensive, which results in the electrochemical properties of these metal ions being similar in both the peptide environment and in bulk water.

Flick, Tawnya G.; Donald, William A.; Williams, Evan R.

2013-02-01

183

Microbial metal-ion reduction and Mars: extraterrestrial expectations?  

Microsoft Academic Search

Dissimilatory metal-ion-reducing bacteria (DMRB) can couple the reduction of a variety of different metal ions to cellular respiration and growth. The excitement of this metabolic group lies not only in the elucidation of a new type of metabolism, but also in the potential use of these abilities for the removal of toxic organics, and in their ability to reduce (and

Kenneth H. Nealson; B. Lea Cox

2002-01-01

184

Ion implantation enhanced metal-Si-metal photodetectors  

SciTech Connect

The quantum efficiency and frequency response of simple Ni-Si-Ni metal-semiconductor-metal (MSM) photodetectors at long wavelengths are significantly enhanced with a simple, ion-implantation step to create a highly absorbing region [approximately] 1 [mu]m below the Si surface. The internal quantum efficiency is improved by a factor of [approximately] 3 at 860 nm (to 64%) and a full factor of ten at 1.06 [mu]m (to 23%) as compared with otherwise identical unimplanted devices. Dark currents are only slightly affected by the implantation process and are as low as 630 pA for a 4.5-[mu]m gap device at 10-V bias. Dramatic improvement in the impulse response is observed, 100 ps vs. 600 ps, also at 10-V bias and 4.5-[mu]m gap, due to the elimination of carrier diffusion tails in the implanted devices. Due to its planar structure, this device is fully VLSI compatible. Potential applications include optical interconnections for local area networks and multi-chip modules.

Sharma, A.K.; Scott, K.A.M.; Brueck, S.R.J. (Univ. of New Mexico, Albuquerque, NM (United States). Center for High Technology Materials); Zolper, J.C.; Myers, D.R. (Sandia National Labs., Albuquerque, NM (United States))

1994-05-01

185

Spectroscopic detection of metals ions using a novel selective sensor  

NASA Astrophysics Data System (ADS)

Colorimetric chemosensors are simple, economical and practical optical approach for detecting toxic metal ions (Hg2+, Pb2+, Ni2+, etc.) in the environment. In this work, we present a simple but highly specific organic compound 4-chloro-2-((E)-((E)-3-(4-(dimethylamino)phenyl)allylidene)amino)phenol (L1) that acts as a colorimetric sensor for divalent metal ions in H2O. The mechanism of the interaction between L1 and various metal-ions has been established by UV-vis absorption and emission spectroscopic experiments that indicate favorable coordination of metal ions with L1 in different solvents. Experimental results indicate that the shape of the electronic transition band of L1 (receptor compound) changed after the interaction with divalent metal-ions, such as Hg2+, Pb2+, Mn2+, Co2+, Cu2+, and Ni2+ in aqueous solution. We found that L1 have a considerable selectivity for Ni2+ ions, even in presence of other metals ions when mixtures of DMSO/H2O as are used as solvents. L1, which has been targeted for sensing transition metal ions, exhibits binding-induced color changes from yellow to pink observed even by the naked eye in presence of Ni2+ ions.

Peralta-Domínguez, D.; Ramos-Ortiz, G.; Maldonado, J. L.; Rodriguez, M.; Meneses-Nava, M. A.; Barbosa-Garcia, O.; Santillan, R.; Farfan, N.

2011-08-01

186

Metal ion complexes of EDTA as solutes for density gradient ultracentrifugation: influence of metal ions.  

PubMed

In the study reported here, we study the nature of the metal ion complexes of EDTA as solute systems for analysis of lipoproteins by density gradient ultracentrifugation (DGU) by varying both the complexing metal ion and the counterion. Specifically, the sodium and cesium salts of complexes of Bi/EDTA, Pb/EDTA, Cd/EDTA, Fe/EDTA, and Cu/EDTA were chosen for this study. We show that useful gradients can be formed within a few hours beginning with a homogeneous solution. Data are presented that provide insight into the nature of how these gradients are formed from these complexes and how the selection of a specific complex can be used to enhance particular regions of the lipoprotein density profile for clinical studies. We also examine the use of equilibrium sedimentation theory to correlate the measured density profiles generated by these complexes with their molecular weight. PMID:16255609

Johnson, Jeffery D; Bell, Natalie J; Donahoe, Erin L; Macfarlane, Ronald D

2005-11-01

187

Polyphosphazene membranes for metal ion separations  

SciTech Connect

The Idaho National Engineering Laboratory (INEL), under sponsorship by the Bureau of Mines, evaluated the use of polyphosphazene-based polymer membranes for chemical separations. Synthetic membranes based on phosphazene inorganic polymers offer the promise of new industrial chemical separation technologies that are more energy efficient and economical than traditional phase change separation processes and extraction techniques. The research focused on the separation of metal ions from aqueous solutions. The polyphosphazene membranes were also tested for gaseous separations, results of which are presented in a separate Report of Investigation. Historically, membranes used for chemical separation have been prepared from organic polymers. In general, these membranes are stable only at temperatures less than 100{degrees}C, within narrow pH ranges, and in a very limited number of organic media. As a result, many organic- based membranes are unsuitable for industrial applications, which often involve harsh environments. In recent years, membrane research has focused on ceramic and metal membranes for use in the adverse environments of separation applications. These membranes are suitable for gas and liquid sieve separation applications, where molecules may be separated based on their molecular size. These membranes are not effective where additional selectivity is needed. A membrane that separates on the basis of solubility and that can perform separations in adverse environments is needed, and this need motivated the investigation of polyphosphazene membranes.

Stone, M.L.

1996-05-01

188

Multiply stripped ion generation in the metal vapor vacuum arc  

SciTech Connect

We consider the charge state distribution of ions produced in the metal vapor vacuum arc plasma discharge. A high current metal ion source, the MEVVA ion source, in which the ion beam is extracted from a metal vapor vacuum arc plasma, has been used to obtain the spectra of multiple charged ions produced within the cathode spots. A computer calculation of the charge state distribution that evolves within the spots via stepwide ionization of ions by electron impact provides a theoretical basis for comparison of the data. In this paper we report on the measured charge state distributions for a wide variety of metallic species and compare these results with the predictions of this theory. 55 refs.

Brown, I.G.; Feinberg, B.; Galvin, J.E.

1986-08-01

189

Metal interactions with voltage- and receptor-activated ion channels.  

PubMed Central

Effects of Pb and several other metal ions on various distinct types of voltage-, receptor- and Ca-activated ion channels have been investigated in cultured N1E-115 mouse neuroblastoma cells. Experiments were performed using the whole-cell voltage clamp and single-channel patch clamp techniques. External superfusion of nanomolar to submillimolar concentrations of Pb causes multiple effects on ion channels. Barium current through voltage-activated Ca channels is blocked by micromolar concentrations of Pb, whereas voltage-activated Na current appears insensitive. Neuronal type nicotinic acetylcholine receptor-activated ion current is blocked by nanomolar concentrations of Pb and this block is reversed at micromolar concentrations. Serotonin 5-HT3 receptor-activated ion current is much less sensitive to Pb. In addition, external superfusion with micromolar concentrations of Pb as well as of Cd and aluminum induces inward current, associated with the direct activation of nonselective cation channels by these metal ions. In excised inside-out membrane patches of neuroblastoma cells, micromolar concentrations of Ca activate small (SK) and big (BK) Ca-activated K channels. Internally applied Pb activates SK and BK channels more potently than Ca, whereas Cd is approximately equipotent to Pb with respect to SK channel activation, but fails to activate BK channels. The results show that metal ions cause distinct, selective effects on the various types of ion channels and that metal ion interaction sites of ion channels may be highly selective for particular metal ions.

Vijverberg, H P; Oortgiesen, M; Leinders, T; van Kleef, R G

1994-01-01

190

Electrospray Ionization Mass Spectrometry: From Cluster Ions to Toxic Metal Ions in Biology.  

National Technical Information Service (NTIS)

This dissertation focused on using electrospray ionization mass spectrometry to study cluster ions and toxic metal ions in biology. In Chapter 2, it was shown that primary, secondary and quarternary amines exhibit different clustering characteristics unde...

H. Stauffer N. Pohl N. B. Lentz R. S. Housk V. S. Y. Lin

2007-01-01

191

Gas-Phase Ion/Ion Reactions of Multiply Protonated Polypeptides with Metal Containing Anions  

PubMed Central

Gas-phase reactions of multiply protonated polypeptides and metal containing anions represent a new methodology for manipulating the cationizing agent composition of polypeptides. This approach affords greater flexibility in forming metal containing ions than commonly used methods, such as electrospray ionization of a metal salt/peptide mixture and matrix-assisted laser desorption. Here, the effects of properties of the polypeptide and anionic reactant on the nature of the reaction products are investigated. For a given metal, the identity of the ligand in the metal containing anion is the dominant factor in determining product distributions. For a given polypeptide ion, the difference between the metal ion affinity and the proton affinity of the negatively charged ligand in the anionic reactant is of predictive value in anticipating the relative contributions of proton transfer and metal ion transfer. Furthermore, the binding strength of the ligand anion to charge sites in the polypeptide correlates with the extent of observed cluster ion formation. Polypeptide composition, sequence, and charge state can also play a notable role in determining the distribution of products. In addition to their usefulness in gas-phase ion synthesis strategies, the reactions of protonated polypeptides and metal containing anions represent an example of a gas-phase ion/ion reaction that is sensitive to polypeptide structure. These observations are noteworthy in that they allude to the possibility of obtaining information, without requiring fragmentation of the peptide backbone, about ion structure as well as the relative ion affinities associated with the reactants.

Newton, Kelly A.; Amunugama, Ravi; McLuckey, Scott A.

2005-01-01

192

Predicting the relative toxicity of metal ions using ion characteristics: Microtox{reg_sign} bioluminescence assay  

Microsoft Academic Search

Quantitative structure-activity relationships have been used to predict the relative toxicity of organic compounds. Although not as common, ion characteristics have also proven useful for predicting the relative toxicity of metal ions. The purpose of this study was to determine if the relative toxicity of metal ions using the Microtox{reg_sign} bioassay was predictable using ion characteristics. Median effect concentrations (EC50s)

John T. McCloskey; Michael C. Newman; Sue B. Clark

1996-01-01

193

The magnetic hyperfine fields of rare earth ions in metals  

Microsoft Academic Search

Data for the magnetic dipole hyperfine interaction of essentially single rare earth ions in metals, measured with different experimental methods, are collected and discussed. Depending on the host, the magnetic hyperfine field of these paramagnetic ions remains undisturbed by the environment, or it is enlarged, or weakened or can even become completely lost. If there are magnetic ions in the

G. Netz

1986-01-01

194

Ionization mechanism in a liquid-metal ion source. Source for high-melting metals  

Microsoft Academic Search

Investigations have been made of the ionization mechanism in a liquid-metal ion source. At the instant of ion current generation\\u000a the surface of a liquid metal emitter frozen in a highvoltage field exhibits microprotrusions pulled from the liquid metal\\u000a by the electric field. A double-focusing mass spectrometer identified two components in the ion beam extracted from the aperture\\u000a in the

G. G. Sikharulidze

1997-01-01

195

Development of a lithium liquid metal ion source for MeV ion beam analysis  

SciTech Connect

Lithium liquid metal ion sources are an attractive complement to the existing gaseous ion sources that are extensively used for ion beam analysis. This is due in part to the high brightness of the liquid metal ion source and in part to the availability of a lithium ion beam. High brightness is of particular importance to MeV ion microprobes which are now approaching current density limitations on targets determined by the ion source. The availability of a lithium beam provides increased capabilities for hydrogen profiling and high resolution Rutherford backscattering spectrometry. This paper describes the design and performance of a lithium liquid metal ion source suitable for use on a 5MV Laddertron accelerator. Operational experience with the source and some of its uses for ion beam analysis are discussed. 8 refs., 2 figs.

Read, P.M.; Maskrey, J.T.; Alton, G.D.

1988-01-01

196

Purification of metal plating rinse waters with chelating ion exchangers  

Microsoft Academic Search

A wide range of chelating ion exchangers was tested for their abilities to remove Zn, Ni, Cu and Cd from solutions simulating waste effluents from the metal-plating industry. The task was to reduce metal discharges to the environment so that metal-plating shops could keep up with the modern, more stringent regulations of waste effluents. The resins were tested by batch

Risto Koivula; Jukka Lehto; Leena Pajo; Thomas Gale; Heikki Leinonen

2000-01-01

197

Ion Beam Superpolishing of Metal Mirrors for High Energy Lasers.  

National Technical Information Service (NTIS)

A new process has been developed which employs a low energy ion beam to superpolish metal surfaces. The process is applicable in principle to all metals. This technique overcomes the tendency of metal surfaces to develop etch patterns and other surface ir...

H. Gelles J. D. Lester R. T. Cook

1975-01-01

198

Adsorption of heavy metal ions on soils and soils constituents  

Microsoft Academic Search

The article focuses on adsorption of heavy metal ions on soils and soils constituents such as clay minerals, metal (hydr)oxides, and soil organic matter. Empirical and mechanistic model approaches for heavy metal adsorption and parameter determination in such models have been reviewed. Sorption mechanisms in soils, the influence of surface functional groups and surface complexation as well as parameters influencing

Heike B Bradl

2004-01-01

199

Modeling (p,xn) reactions producing proton-rich nuclides for radioactive ion beam studies  

SciTech Connect

Over the last few years, an intense worldwide interest has grown in the use of radioactive ion beams (RIB) to study the properties of nuclei far from stability. The relatively recent technological developments that have enabled the production of high-quality radioactive beams promise to lead to a renaissance in nuclear structure and nuclear reaction physics, as well as nuclear astrophysics. Group T-2 at Los Alamos has been working with US Nuclear Reaction Data Network Radioactive Ion Beam Task Force to address RIB nuclear data needs. The current focus is nuclear data needed to guide the choice of targets for the production of various radioactive product species using the isotope-separation on line (ISOL) method; future work will include the study of RIB nuclear reaction and structure physics. Laboratories that are undertaking RIB studies with the ISOL method in the US are principally Oak Ridge National Laboratory (ORNL) and Argonne National Laboratory (ANL).

Chadwick, M.B.; Young, P.G.

1998-03-01

200

Modeling complex vapor-transport systems using Monte-Carlo techniques: Radioactive ion beam applications  

Microsoft Academic Search

A Monte-Carlo code has been developed that can be used to optimally design vapor transport systems for isotope-separator-on-line-based radioactive ion beam facilities in lieu of costly iterative trial and error design methods. The code provides a powerful means for delineating diffusion-release and effusive-flow (molecular-flow) processes, in combination, the delay times of which are principal intensity limiters of short-lived radioactive species

Y. Zhang; G. D. Alton

2005-01-01

201

Radioactive Ion Beams at FAIR-NuSTAR  

SciTech Connect

The future FAIR facility will open up an unprecedented range of exotic nuclear beams in the energy interval between 0-1.5 GeV/u produced by the Super-FRS. The envisaged experimental programme with radioactive beams, being prepared within the NuSTAR collaboration, will cover most aspects of contemporary physics within nuclear structure, astrophysics and reactions.

Nilsson, Thomas [Fundamental Physics, Chalmers Tekniska Hogskola, Gothenburg (Sweden)

2009-06-03

202

Ion-exchange material and method of storing radioactive wastes  

DOEpatents

A new cation exchanger is a modified tobermorite containing aluminum isomorphously substituted for silicon and containing sodium or potassium. The exchanger is selective for lead, rubidium, cobalt, and cadmium and is selective for cesium over calcium or sodium. The tobermorites are compatible with cement and are useful for the long-term fixation and storage of radioactive nuclear wastes.

Komarneni, S.; Roy, D.M.

1983-10-31

203

Operational characteristics of a metal vapor vacuum arc ion source  

SciTech Connect

The MEVVA ion source can produce high current pulsed beams of metallic ions using a metal vapor vacuum arc discharge as the plasma medium from which the ions are extracted. In this study, the operational characteristics of the MEVVA IV ion source are summarized. Results are presented of measurements of the ion beam current as a function of arc current over a range of extraction voltage. Ti, Ta and Pb were examined as the cathode materials. The arc current ranged from 50A to 250A and the extraction voltage from 10kV to 80kV. The ion beam current was measured at two different distances from the ion source using Faraday cups, so as to investigate the beam divergence. Additionally, the cathode erosion rates were measured. Optimum operating conditions of the MEVVA ion source were determined. 10 refs., 6 figs.

Shiraishi, Hiroshi; Brown, I.G. (Nippon Steel Corp., Kitakyushu (Japan); Lawrence Berkeley Lab., CA (USA))

1989-06-01

204

Applications of the MEVVA high current metal ion source  

SciTech Connect

A new kind of ion source has been developed in which a metal vapor vacuum arc (MEVVA) is used to produce the plasma from which the ion beam is extracted. The novel and exciting feature of this source is the very high metal ion beam current attainable. A total ion beam current of over 1 Ampere has been extracted from the embodiment of the concept that we're presently using, and this is not a limit of the method. The source was developed to upgrade the uranium ion beam intensity of the Bevatron, LBL's heavy ion synchrotron, for basic nuclear physics research. Other important applications include its use within the Heavy Ion Fusion research effort; for ion implantation; and for other basic research uses. In this paper the source is described briefly, its performance outlined, and its poential and limitations for a variety of applications is discussed.

Brown, I.G.

1986-08-01

205

Catalysis using hydrous metal oxide ion exchangers  

DOEpatents

In a process which is catalyzed by a catalyst comprising an active metal on a carrier, said metal being active as a catalyst for the process, an improvement is provided wherein the catalyst is a hydrous, alkali metal or alkaline earth metal titanate, zirconate, niobate or tantalate wherein alkali or alkaline earth metal cations have been exchanged with a catalytically effective amount of cations of said metal.

Dosch, R.G.; Stephens, H.P.; Stohl, F.V.

1983-07-21

206

Catalysis using hydrous metal oxide ion exchanges  

DOEpatents

In a process which is catalyzed by a catalyst comprising an active metal on a carrier, said metal being active as a catalyst for the process, an improvement is provided wherein the catalyst is a hydrous, alkali metal or alkaline earth metal titanate, zirconate, niobate or tantalate wherein alkali or alkaline earth metal cations have been exchanged with a catalytically effective amount of cations of said metal.

Dosch, Robert G. (Albuquerque, NM); Stephens, Howard P. (Albuquerque, NM); Stohl, Frances V. (Albuquerque, NM)

1985-01-01

207

Determination of Trace Metal Ion Concentrations in Seawater  

NASA Astrophysics Data System (ADS)

An experimental procedure is described for the pre-concentration of trace metal ions from seawater. The procedure is suitable for senior students in analytical chemistry/instrumental analysis. Hydrated iron (III) oxide is recommended for the coprecipitation of trace transition metal ions from aqueous solution. Chelating ion-exchange with Chelex-100 is similarly recommended. Both techniques have been successfully used here. After leaching the precipitate or desorbing the resin with nitric acid solution, the trace metal ion content of the concentrate is determined using a suitably sensitive analytical technique such as graphite furnace atomic absorption spectrophotometry. The values obtained are used to calculate the concentration of trace metal ions in the seawater.

Quigley, Michael N.; Vernon, Fredrick

1996-07-01

208

Advances in cement solidification technology for waste radioactive ion exchange resins: a review.  

PubMed

Treatment and disposal of waste radioactive ion exchange resins is one of the most urgent problems for nuclear industries in China. Cement solidification technology has many advantages, such as requiring simple equipment, easy scaling-up, low working temperature, no trouble of gas cleaning and low cost. It is a suitable technology for treatment of waste radioactive resins, and has been widely used. The new developments and theoretical basis of cement solidification of radioactive resins were introduced in this paper. The cement solidification technology suitable for China and the questions needed to solve were also discussed. PMID:16388899

Li, Junfeng; Wang, Jianlong

2006-01-04

209

Proceedings of the workshop on prospects for research with radioactive beams from heavy ion accelerators  

SciTech Connect

The SuperHILAC Users Executive Committee organized a workshop on Prospects for Research with Radioactive Beams from Heavy Ion Accelerators. The main purpose of the workshop was to bring together a diverse group of scientists who had already done experients with radioactive beams or were interested in their use in the future. The topics of the talks ranged from general nuclear physics, astrophysics, production of radioactive beams and high energy projectile fragmentation to biomedical applications. This publication contains the abstracts of the talks given at the workshop and copies of the viewgraphs as they were supplied to the editor.

Nitschke, J.M. (ed.)

1984-04-01

210

EBIS charge breeder for radioactive ion beams at ATLAS  

Microsoft Academic Search

The construction of the Californium Rare Isotope Breeder Upgrade (CARIBU) for the Argonne National Laboratory ATLAS facility is completed and its commissioning is being performed. In its full capacity, the CARIBU facility will use fission fragments from a 1 Curie (Ci) 252Cf source. The ions will be thermalized and collected into a low-energy ion beam by a helium gas catcher,

P. Ostroumov; S. Kondrashev; R. Pardo; G. Savard; R. Vondrasek; J. Alessi; E. Beebe; A. Pikin

2010-01-01

211

Industrial Application of Radioactive Ion Beams at the RIKEN RI Beam Factory  

SciTech Connect

The Radioactive Ion Beam Factory (RIBF) at RIKEN is a heavy-ion accelerator facility that can provide intensive beams of radioactive isotopes (RI beam) produced at in-flight RI-beam separators. While the facility is used for experiments of various basic research fields, a new project has been started to open the facility to non-academic proposals from industry. We show an overview of the RIBF and the project of industrial use, and present a utilization of an RI-beam for development of wear diagnostics of industrial materials.

Kambara, Tadashi; Yoshida, Atsushi; Yanagisawa, Yoshiyuki; Kameda, Daisuke; Fukuda, Naoki; Ohnishi, Tetsuya; Kubo, Toshiyuki [Nishina Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Uemoto, Ryuji; Nagano, Akira; Uno, Hiroyuki [S. H. I. Examination and Inspection, Ltd., 1501 Imazaike, Saijo, Ehime 799-1393 (Japan)

2011-12-13

212

Radioactive ion beams at the Bevalac: Greatly enhanced fragment separation for high energy beams  

SciTech Connect

Radioactive beams are routinely produced at the Bevalac by the fragmentation process. High energy beams (energies {approximately} 800 MeV/u) produce fragments with nearly the original beam momentum, forming a radioactive ion beam. A new beamline is being constructed which will provide resolution for ions approaching the mass 100 region, compared to the present mass 20 capability, by strongly increasing the dispersion and also increasing the beam size for easier tuning and more effective collimation. In addition, the angular acceptance has been more than doubled. Details of the design will be presented. 6 refs., 4 figs., 1 tab.

Feinberg, B.; Kalnins, J.G.; Krebs, G.F.

1990-09-01

213

Recent results of experiments with radioactive 21Na and 7Be ion beams  

NASA Astrophysics Data System (ADS)

We report here on experiments with radioactive 21Na and 7Be beams performed by Colorado School of Mines students at the ISAC facility of TRIUMF and the Holifield Radioactive Ion Beam Facility (HRIBF) of ORNL. At TRIUMF, the DRAGON recoil separator and its segmented BGO array were used to investigate higher energy resonances in the reaction H(21Na, ?)22Mg. Using the HRIBF we performed an experiment with a 7Be ion beam to measure scattering off Hydrogen and Carbon. Both elastic 7Be + p scattering and for the first time resonant inelastic scattering 7Be(p, p?)7Be? were observed.

Greife, U.; Livesay, J.; Jewett, C.; Chipps, K.; Sarazin, F.; Bardayan, D.; Blackmon, J.; Nesaraja, C.; Smith, M. S.; Champagne, A.; Fitzgerald, R.; Jones, K.; Thomas, J.; Kozub, R.; Buchmann, L.; Caggiano, J.; Hunter, D.; Hutcheon, D.; Olin, A.; Ottewell, D.; Rogers, J.; Ruiz, C.; Ruprecht, G.; Trinczek, M.; Vockenhuber, C.; Bishop, S.; D'Auria, J.; Lamay, M.; Liu, W.; Wrede, C.; Chatterjee, M. L.; Chen, A. A.; Pearson, J.; Engel, S.; Laird, A. M.; Gigliotti, D.; Hussein, A.

2007-08-01

214

Progress in metal ion separation and preconcentration : an overview.  

SciTech Connect

A brief historical perspective covering the most mature chemically-based metal ion separation methods is presented, as is a summary of the recommendations made in the 1987 National Research Council (NRC) report entitled ''Separation and Purification: Critical Needs and Opportunities''. A review of Progress in Metal Ion Separation and Preconcentration shows that advances are occurring in each area of need cited by the NRC. Following an explanation of the objectives and general organization of this book, the contents of each chapter are briefly summarized and some future research opportunities in metal ion separations are presented.

Bond, A. H.

1998-05-19

215

Negative ion photoelectron spectroscopy of metal clusters, metal-organic clusters, metal oxides, and metal-doped silicon clusters  

Microsoft Academic Search

The techniques of time-of-flight mass spectrometry and negative ion photoelectron spectroscopy were utilized to study metal clusters (Mgn -, Znn-, Can -, Mnn-, CuAln -, LiAln-, and NmSn n-), metal-organic complexes (Tin(benzene) m-, Fn(benzene)m- , Nin(benzene)m-), metal oxides(AuO-, PtO-, TaOn -, HfO2-, and MnnO -), and metal-doped semiconductor clusters (CrSin -, GdmSin- and HoSi n-). The study of magnesium and

Weijun Zheng

2005-01-01

216

Heating of metals in swift heavy ion tracks by electron-ion energy exchange  

Microsoft Academic Search

The rate of the heat transfer from the excited electrons to the ion lattice in swift heavy ion tracks in metals considerably deviates from the predictions of the electron-phonon coupling model. Due to the short times of the electron gas cooling down this rate is insensitive to a particular atomic structure of irradiated metals. For the initial temperature of the

A. E. Volkov; V. A. Borodin

1998-01-01

217

Heating of metals in swift heavy ion tracks by electron–ion energy exchange  

Microsoft Academic Search

The rate of the heat transfer from the excited electrons to the ion lattice in swift heavy ion tracks in metals considerably deviates from the predictions of the electron-phonon coupling model. Due to the short times of the electron gas cooling down this rate is insensitive to a particular atomic structure of irradiated metals. For the initial temperature of the

A. E. Volkov; V. A. Borodin

1998-01-01

218

Prospects for studies of astrophysical interest with radioactive ion beams  

SciTech Connect

Realistic estimates of the new nuclei that will become accessible for study with the planned new generation of radioactive beam facilities are compared with the predicted paths of the various nucleosynthetic processes. These facilities should permit studies of essentially the complete set of nuclei associated with the rp- and p-processes, the CNL cycle, and big-bang nucleosynthesis, as well as the r-process below A {congruent} 150.

Garrett, J.D.

1992-10-01

219

Prospects for studies of astrophysical interest with radioactive ion beams  

SciTech Connect

Realistic estimates of the new nuclei that will become accessible for study with the planned new generation of radioactive beam facilities are compared with the predicted paths of the various nucleosynthetic processes. These facilities should permit studies of essentially the complete set of nuclei associated with the rp- and p-processes, the CNL cycle, and big-bang nucleosynthesis, as well as the r-process below A {congruent} 150.

Garrett, J.D.

1992-01-01

220

Applications of radioactive ion beams to solid-state physics  

Microsoft Academic Search

:   Radioactive atoms have been used in solid-state physics and in material science for many decades. Besides their classical\\u000a application as tracer for diffusion studies, nuclear techniques such as Mößbauer spectroscopy, perturbed angular correlation,\\u000a ?-NMR, and emission channeling have used nuclear properties (via hyperfine interactions or emitted ?- or ?-particles) to gain\\u000a microscopical information on the structural and dynamical properties

M. Deicher

2002-01-01

221

Metal ion acquisition in Staphylococcus aureus: overcoming nutritional immunity  

PubMed Central

Transition metals are essential nutrients to virtually all forms of life, including bacterial pathogens. In Staphylococcus aureus, metal ions participate in diverse biochemical processes such as metabolism, DNA synthesis, regulation of virulence factors, and defense against oxidative stress. As an innate immune response to bacterial infection, vertebrate hosts sequester transition metals in a process that has been termed “nutritional immunity.” To successfully infect vertebrates, S. aureus must overcome host sequestration of these critical nutrients. The objective of this review is to outline the current knowledge of staphylococcal metal ion acquisition systems, as well as to define the host mechanisms of nutritional immunity during staphylococcal infection.

Cassat, James E.

2013-01-01

222

Metal ion removal from aqueous solution using physic seed hull.  

PubMed

The potential of physic seed hull (PSH), Jantropha curcas L. as an adsorbent for the removal of Cd(2+) and Zn(2+) metal ions from aqueous solution has been investigated. It has been found that the amount of adsorption for both Cd(2+) and Zn(2+) increased with the increase in initial metal ions concentration, contact time, temperature, adsorbent dosage and the solution pH (in acidic range), but decreased with the increase in the particle size of the adsorbent. The adsorption process for both metal ions on PSH consists of three stages-a rapid initial adsorption followed by a period of slower uptake of metal ions and virtually no uptake at the final stage. The kinetics of metal ions adsorption on PSH followed a pseudo-second-order model. The adsorption equilibrium data were fitted in the three adsorption isotherms-Freundlich, Langmuir and Dubinin-Radushkevich isotherms. The data best fit in the Langmuir isotherm indication monolayer chemisorption of the metal ions. The adsorption capacity of PSH for both Zn(2+) and Cd(2+) was found to be comparable with other available adsorbents. About 36-47% of the adsorbed metal could be leached out of the loaded PSH using 0.1M HCl as the eluting medium. PMID:20362390

Mohammad, Masita; Maitra, Saikat; Ahmad, Naveed; Bustam, Azmi; Sen, T K; Dutta, Binay K

2010-03-10

223

Metal ion binding and the folding of the hairpin ribozyme.  

PubMed Central

The hairpin ribozyme comprises two formally unpaired loops carried on two arms of a four-way helical RNA junction. Addition of divalent metal ions brings about a conformational transition into an antiparallel structure in which there is an intimate association between the loops to generate the active form of the ribozyme. In this study, we have used fluorescence resonance energy transfer to analyze the global folding of the complete ribozyme, and the simple four-way junction derived from it, over a wide concentration range of divalent and monovalent metal ions. The simple junction undergoes an ion-induced rotation into an antiparallel form. In the presence of a constant background concentration of sodium ions, the magnesium-ion-induced transition is characterized by noncooperative binding with a Hill coefficient n = 1. By contrast, the magnesium-ion-induced folding of the complete ribozyme is more complex, involving two distinct binding phases. The first phase occurs in the micromolar range, and involves the cooperative binding of at least three magnesium ions. This can also be achieved by high concentrations of sodium ions, and is therefore likely to be due to diffuse binding of cations at the junction and the interface of the loop-loop interaction. The second phase occurs in the millimolar range, and can only be induced by divalent metal ions. This transition occurs in response to the noncooperative, site-specific binding of magnesium ions. We observe a good correlation between the extent of ion-induced folding and cleavage activity.

Wilson, Timothy J; Lilley, David M J

2002-01-01

224

MODELING AN ION EXCHANGE PROCESS FOR CESIUM REMOVAL FROM ALKALINE RADIOACTIVE WASTE SOLUTIONS  

SciTech Connect

The performance of spherical Resorcinol-Formaldehyde ion-exchange resin for the removal of cesium from alkaline radioactive waste solutions has been investigated through computer modeling. Cesium adsorption isotherms were obtained by fitting experimental data using a thermodynamic framework. Results show that ion-exchange is an efficient method for cesium removal from highly alkaline radioactive waste solutions. On average, two 1300 liter columns operating in series are able to treat 690,000 liters of waste with an initial cesium concentration of 0.09 mM in 11 days achieving a decontamination factor of over 50,000. The study also tested the sensitivity of ion-exchange column performance to variations in flow rate, temperature and column dimensions. Modeling results can be used to optimize design of the ion exchange system.

Smith, F; Luther Hamm, L; Sebastian Aleman, S; Johnston Michael, J

2008-08-26

225

Studies of sorbent\\/ion-exchange materials for the removal of radioactive strontium from liquid radioactive waste and high hardness groundwaters  

Microsoft Academic Search

Different sorbents were studied in terms of their full-scale applicability for radioactive strontium removal in low-level liquid radioactive waste (LLRW) management. The following types of sorbent\\/ion-exchange materials were investigated: natural zeolite–clinoptilolite, modified natural clinoptilolite, synthetic zeolites, new synthetic crystalline materials selective to strontium, ion-exchange resins, and modified fiber sorbents. Simulated solutions for experimental tests were prepared according to the composition

Dmitry V Marinin; Garrett N Brown

2000-01-01

226

Ion exchange extraction of heavy metals from wastewater sludges.  

PubMed

Heavy metals are common contaminants of some industrial wastewater. They find their way to municipal wastewaters due to industrial discharges into the sewerage system or through household chemicals. The most common heavy metals found in wastewaters are lead, copper, nickel, cadmium, zinc, mercury, arsenic, and chromium. Such metals are toxic and pose serious threats to the environment and public health. In recent years, the ion exchange process has been increasingly used for the removal of heavy metals or the recovery of precious metals. It is a versatile separation process with the potential for broad applications in the water and wastewater treatment field. This article summarizes the results obtained from a laboratory study on the removal of heavy metals from municipal wastewater sludges obtained from Ardhiya plant in Kuwait. Data on heavy metal content of the wastewater and sludge samples collected from the plant are presented. The results obtained from laboratory experiments using a commercially available ion exchange resin to remove heavy metals from sludge were discussed. A technique was developed to solubilize such heavy metals from the sludge for subsequent treatment by the ion exchange process. The results showed high efficiency of extraction, almost 99.9%, of heavy metals in the concentration range bound in wastewater effluents and sludges. Selective removal of heavy metals from a contaminated wastewater/sludge combines the benefits of being economically prudent and providing the possibility of reuse/recycle of the treated wastewater effluents and sludges. PMID:15027828

Al-Enezi, G; Hamoda, M F; Fawzi, N

2004-01-01

227

Determination of metal ions by ion chromatography with precolumn electrochemical preconcentration  

Microsoft Academic Search

The determination of heavy metals in concentrations less than 10-6 mol\\/L by ion chromatography with conductivity detection requires a preconcentration step. Therefore, a special electrochemical equipment and method was developed for the on-line preconcentration of the divalent metals Ni, Co, Zn and Cd and their subsequent ion chromatographic determination. The loop of the injection valve of an ion chromatograph was

Frank Hißner; Jürgen Mattusch; G. Werner

1996-01-01

228

Effects of metal ions on fibroblasts and spiral ganglion cells.  

PubMed

Degeneration of spiral ganglion cells (SGC) after deafness and fibrous tissue growth around the electrode carrier after cochlear implantation are two of the major challenges in current cochlear implant research. Metal ions are known to possess antimicrobial and antiproliferative potential. The use of metal ions could therefore provide a way to reduce tissue growth around the electrode array after cochlear implantation. Here, we report on in vitro experiments with different concentrations of metal salts with antiproliferative and toxic effects on fibroblasts, PC-12 cells, and freshly isolated spiral ganglion cells, the target cells for electrical stimulation by a cochlear implant. Standard cell lines (NIH/3T3 and L-929 fibroblasts and PC-12 cells) and freshly isolated SGC were incubated with concentrations of metal ions between 0.3 ?mol/liter and 10 mmol/liter for 48 hr. Cell survival was investigated by neutral red uptake, CellQuantiBlue assay, or counting of stained surviving neurons. Silver ions exhibited distinct thresholds for proliferating and confluent cells. For zinc ions, the effective concentration was lower for fibroblasts than for PC-12 cells. SGC showed comparable thresholds for reduced cell survival not only for silver and zinc ions but also for copper(II) ions, indicating that these ions might be promising for reducing tissue growth on the surface of CI electrode arrays. These effects were also observed when combinations of two of these ions were investigated. PMID:21312225

Paasche, G; Ceschi, P; Löbler, M; Rösl, C; Gomes, P; Hahn, A; Rohm, H W; Sternberg, K; Lenarz, T; Schmitz, K-P; Barcikowski, S; Stöver, T

2011-01-13

229

Effects of metal ions on fibroblasts and spiral ganglion cells.  

PubMed

Degeneration of spiral ganglion cells (SGC) after deafness and fibrous tissue growth around the electrode carrier after cochlear implantation are two of the major challenges in current cochlear implant research. Metal ions are known to possess antimicrobial and antiproliferative potential. The use of metal ions could therefore provide a way to reduce tissue growth around the electrode array after cochlear implantation. Here, we report on in vitro experiments with different concentrations of metal salts with antiproliferative and toxic effects on fibroblasts, PC-12 cells, and freshly isolated spiral ganglion cells, the target cells for electrical stimulation by a cochlear implant. Standard cell lines (NIH/3T3 and L-929 fibroblasts and PC-12 cells) and freshly isolated SGC were incubated with concentrations of metal ions between 0.3 ?mol/liter and 10 mmol/liter for 48 hr. Cell survival was investigated by neutral red uptake, CellQuantiBlue assay, or counting of stained surviving neurons. Silver ions exhibited distinct thresholds for proliferating and confluent cells. For zinc ions, the effective concentration was lower for fibroblasts than for PC-12 cells. SGC showed comparable thresholds for reduced cell survival not only for silver and zinc ions but also for copper(II) ions, indicating that these ions might be promising for reducing tissue growth on the surface of CI electrode arrays. These effects were also observed when combinations of two of these ions were investigated. © 2011 Wiley-Liss, Inc. PMID:21234893

Paasche, G; Ceschi, P; Löbler, M; Rösl, C; Gomes, P; Hahn, A; Rohm, H W; Sternberg, K; Lenarz, T; Schmitz, K-P; Barcikowski, S; Stöver, T

2011-01-13

230

Extracting metal ions with diphosphonic acid, or derivative thereof  

DOEpatents

Thermodynamically-unstable complexing agents which are diphosphonic acids and diphosphonic acid derivatives (or sulphur containing analogs), like carboxyhydroxymethanediphosphonic acid and vinylidene-1,1-diphosphonic acid, are capable of complexing with metal ions, and especially metal ions in the II, III, IV, V and VI oxidation states, to form stable, water-soluble metal ion complexes in moderately alkaline to highly-acidic media. However, the complexing agents can be decomposed, under mild conditions, into non-organic compounds which, for many purposes are environmentally-nondamaging compounds thereby degrading the complex and releasing the metal ion for disposal or recovery. Uses for such complexing agents as well as methods for their manufacture are also described.

Horwitz, Earl P. (Argonne, IL); Gatrone, Ralph C. (Argonne, IL); Nash, Kenneth L. (Argonne, IL)

1994-01-01

231

Kinetic Analysis of Metal Ions: An Undergraduate Laboratory Experiment.  

ERIC Educational Resources Information Center

Reports on the adaptation of a kinetic method of analysis of metal ions for use in an undergraduate teaching laboratory. Background information, procedures used, and analysis of typical results obtained are provided. (JN)

Williams, Kathryn R.

1985-01-01

232

Defect Production and Electronic Stopping for Light Ions in Metals.  

National Technical Information Service (NTIS)

A method for determining effective electronic stopping powers in metals is presented. The method involves measuring damage rates in thin films as a function of ion energy. The experimental results are compared with predictions based on Monte Carlo compute...

R. S. Averback R. Benedek K. L. Merkle L. J. Thompson

1979-01-01

233

Catalytic Oxidation by Transition Metal Ions in Zeolites.  

National Technical Information Service (NTIS)

The regular cavities of zeolites form a unique environment for carrying out both stoichiometric and catalytic oxidation reactions. Transition metal ions such as molybdenum and cobalt may be introduced into the zeolite, and, as well, the acidity may be var...

J. H. Lunsford

1988-01-01

234

High-current metal ion beam extraction from a multicusp ion source  

Microsoft Academic Search

Improvements have been made in a multicusp ion source, which made it possible to produce metal–vapor plasma and extract a high-current metal ion beam. In the discharge chamber, double radiation shields were set and the inner shields were heated to 1860 K. Therefore, it became possible to maintain enough metal–vapor density to produce plasma without the use of support gas.

Yutaka Inouchi; Hideki Tanaka; Hiroshi Inami; Fumio Fukumaru; Kouzi Matsunaga

1990-01-01

235

A design of large current ion gun employing liquid metal ion source  

Microsoft Academic Search

A lens system for a large current liquid metal ion source has been designed by a numerical computer simulation method. As a computed result, the lens system can focus an ion beam having an emission angle of 60° to a beam having a radius of 1.8 mm at 1 m from the ion source. Following the simulated result, the lens

Yuzo Mori; Hui Wang; Katsuyoshi Endo; Kazuto Yamauchi; Takashi Ide

1990-01-01

236

Electrospray Ionization Mass Spectrometry: From Cluster Ions to Toxic metal Ions in Biology  

Microsoft Academic Search

This dissertation focused on using electrospray ionization mass spectrometry to study cluster ions and toxic metal ions in biology. In Chapter 2, it was shown that primary, secondary and quarternary amines exhibit different clustering characteristics under identical instrument conditions. Carbon chain length also played a role in cluster ion formation. In Chapters 3 and 4, the effects of solvent types\\/ratios

Nicholas B. Lentz

2007-01-01

237

Ion metal synthesis in viscous organic matter  

Microsoft Academic Search

The viscosity of the irradiated target as new parameter was introduced in ion implantation physics of organic matter. It was experimentally shown that using this parameter one enables to monitor the process of ion synthesis of thin granular impurity films. As an example, the results of high-dose implantation of Co+ and Ag+ ions in viscous epoxy experimenting stages of cure

I. B. Khaibullin; R. I. Khaibullin; S. N. Abdullin; A. L. Stepanov; Yu. N. Osin; V. V. Bazarov; S. P. Kurzin

1997-01-01

238

Tailoring fission dynamics using fragmentation of radioactive heavy ion beams  

NASA Astrophysics Data System (ADS)

An innovative approach for studying transient effects in nuclear fission is proposed. Fragmentation of radioactive actinides is employed to prepare fissile nuclei in well-defined initial conditions, and the fission-fragment nuclear charge distribution is used to establish a clock for the dynamical evolution of the system. Based on a so-far un-reached large number of fissioning systems, the study demonstrates the undeniable manifestation of transient effects at high excitation energy and addresses the question about the influence of initial deformation.

Schmitt, C.; Kelic, A.; Schmidt, K.-H.; Heinz, A.; Jurado, B.; Nadtochy, P. N.

2009-10-01

239

Study of a liquid metal ion source for external ion injection into electron-beam ion source  

NASA Astrophysics Data System (ADS)

A liquid metal ion source (LMIS) has several attractive features as an external injector of primary ions (mostly metallic ions) into electron-beam ion source (EBIS). It does not use a buffer gas and therefore it provides only a very small gas load to the system; its control and operation are simple, power consumption does not exceed 10 W, and beam pulses are very stable. A gold-silicon LMIS was supplied by FEI Company (http://www.feibeamtech.com/pages/liquid.html) and tested in a pulsed regime with an ion pulse width of 2 ms and frequency up to 5 Hz. Total extracted ion current reached 50 ?A and the normalized emittance of the total ion beam was 0.05? mm mrad. The results of this test, as well as results of experiments in which this ion source is used for injection of Au ions into EBIS, are presented.

Pikin, A.; Alessi, J. G.; Beebe, E. N.; Kponou, A.; Prelec, K.

2006-03-01

240

Metal ion implantation for large scale surface modification  

SciTech Connect

Intense energetic beams of metal ions can be produced by using a metal vapor vacuum arc as the plasma discharge from which the ion beam is formed. We have developed a number of ion sources of this kind and have built a metal ion implantation facility which can produce repetitively pulsed ion beams with mean ion energy up to several hundred key, pulsed beam current of more than an ampere, and time averaged current of several tens of milliamperes delivered onto a downstream target. We've also done some preliminary work on scaling up this technology to very large size. For example, a 50-cm diameter (2000 cm[sup 2]) set of beam formation electrodes was used to produce a pulsed titanium beam with ion current over 7 amperes at a mean ion energy of 100 key. Separately, a dc embodiment has been used to produce a dc titanium ion beam with current over 600 mA, power supply limited in this work, and up to 6 amperes of dc plasma ion current was maintained for over an hour. In a related program we've developed a plasma immersion method for applying thin metallic and compound films in which the added species is atomically mixed to the substrate. By adding a gas flow to the process, well-bonded compound films can also be formed; metallic films and multilayers as well as oxides and nitrides with mixed transition zones some hundreds of angstroms thick have been synthesized. Here we outline these parallel metal-plasma-based research programs and describe the hardware that we've developed and some of the surface modification research that we've done with it.

Brown, I.G.

1992-10-01

241

Exploiting neutron-rich radioactive ion beams to constrain the symmetry energy  

NASA Astrophysics Data System (ADS)

The Modular Neutron Array (MoNA) and 4 Tm Sweeper magnet were used to measure the free neutrons and heavy charged particles from the radioactive ion beam induced 32Mg+9Be reaction. The fragmentation reaction was simulated with the constrained molecular dynamics model (CoMD), which demonstrated that the of the heavy fragments and free neutron multiplicities were observables sensitive to the density dependence of the symmetry energy at subsaturation densities. Through comparison of these simulations with the experimental data, constraints on the density dependence of the symmetry energy were extracted. The advantage of radioactive ion beams as a probe of the symmetry energy is demonstrated through examination of CoMD calculations for stable and radioactive-beam-induced reactions.

Kohley, Z.; Christian, G.; Baumann, T.; DeYoung, P. A.; Finck, J. E.; Frank, N.; Jones, M.; Smith, J. K.; Snyder, J.; Spyrou, A.; Thoennessen, M.

2013-10-01

242

Element synthesis calculations for stellar explosions: robust uncertainties, sensitivities, and radioactive ion beam measurements  

Microsoft Academic Search

We utilize multiple-zone, post-processing element synthesis calculations to determine the impact of recent ORNL radioactive ion beam measurements on predictions of novae and X-ray burst simulations. We also assess the correlations between all relevant reaction rates and all synthesized isotopes, and translate nuclear reaction rate uncertainties into abundance prediction uncertainties, via a unique Monte Carlo technique.

Michael Scott Smith; William Raphael Hix; Suzanne T Parete-Koon; Luc Lucius Dessieux Jr; Zhanwen Ma; Sumner Starrfield; Daniel W. Bardayan; Michael W. Guidry; Donald L. Smith; Jeffery C. Blackmon; Anthony Mezzacappa

2004-01-01

243

Michigan state upgrade to produce intense radioactive ion beams by fragmentation technique  

SciTech Connect

This article describes the planned upgrading of accelerator facilities to produce intense radioactive ion beams, by a fragmentation technique, for experimental simulation of nucleosynthesis in novas and supernovas. (AIP) {ital 1997 American Institute of Physics.} {copyright} {ital 1997} {ital American Institute of Physics}

Lubkin, G.B. [Physics Today, American Center for Physics, One Physics Ellipse, College Park, Maryland 20740-3843 (United States)

1997-05-01

244

The latest from the new Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory  

SciTech Connect

The status of new Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory (ORNL), which is slated to start its scientific program late in 1996 is discussed, as is the new experimental equipment which is being constructed at this facility. Information on the early scientific program is also given.

Garrett, J.D.

1996-10-01

245

Element Synthesis Calculations for Stellar Explosions: Robust Uncertainties, Sensitivities, and Radioactive Ion Beam Measurements  

SciTech Connect

We utilize multiple-zone, post-processing element synthesis calculations to determine the impact of recent ORNL radioactive ion beam measurements on predictions of novae and X-ray burst simulations. We also assess the correlations between all relevant reaction rates and all synthesized isotopes, and translate nuclear reaction rate uncertainties into abundance prediction uncertainties, via a unique Monte Carlo technique.

Smith, Michael Scott [ORNL; Hix, William Raphael [ORNL; Parete-Koon, Suzanne T [ORNL; Dessieux Jr, Luc Lucius [ORNL; Ma, Zhanwen [ORNL; Starrfield, Sumner [Arizona State University; Bardayan, Daniel W [ORNL; Guidry, Mike W [ORNL; Smith, Donald L. [Argonne National Laboratory (ANL); Blackmon, Jeff C [ORNL; Mezzacappa, Anthony [ORNL

2004-12-01

246

Element synthesis calculations for stellar explosions: robust uncertainties, sensitivities, and radioactive ion beam measurements  

NASA Astrophysics Data System (ADS)

We utilize multiple-zone, post-processing element synthesis calculations to determine the impact of recent ORNL radioactive ion beam measurements on predictions of novae and X-ray burst simulations. We also assess the correlations between all relevant reaction rates and all synthesized isotopes, and translate nuclear reaction rate uncertainties into abundance prediction uncertainties, via a unique Monte Carlo technique.

Smith, Michael S.; Hix, W. Raphael; Parete-Koon, Suzanne; Dessieux, Luc; Ma, Zhanwen; Starrfield, Sumner; Bardayan, Daniel W.; Guidry, Michael W.; Smith, Donald L.; Blackmon, Jeffery C.; Mezzacappa, Anthony

2004-12-01

247

Ion Beam Mixing in Metallic Glasses at Low Temperatures.  

National Technical Information Service (NTIS)

Measurements of ion beam mixing of tracer impurities in metallic glasses and in the pure crystalline elements comprising the glasses were performed at approx.80 K. It was observed that the ion mixing efficiency of the tracer impurities was greater in the ...

H. Hahn T. D. de la Rubia R. S. Averback

1987-01-01

248

SEPARATION OF CERTAIN METAL IONS FROM MIXTURES BY ELECTROCHROMATOGRAPHY  

Microsoft Academic Search

The ions of one or a few metals were separated from multicomponent ; mixtures by one-way electrochromatography. The separation of particular ions is ; based upon differential electrical migration in stabilized solutions of specially ; selected background electrolytes. These methods, which have several advantages ; over chemical methods of segregation, permitted the isolation and idertification ; of one or a

Joseph Sherma; G. H. Evans; H. D. Jr. Frame; H. H. Strain

1963-01-01

249

Modification of medical metals by ion implantation of copper  

NASA Astrophysics Data System (ADS)

The effect of copper ion implantation on the antibacterial activity, wear performance and corrosion resistance of medical metals including 317 L of stainless steels, pure titanium, and Ti Al Nb alloy was studied in this work. The specimens were implanted with copper ions using a MEVVA source ion implanter with ion doses ranging from 0.5 × 1017 to 4 × 1017 ions/cm2 at an energy of 80 keV. The antibacterial effect, wear rate, and inflexion potential were measured as a function of ion dose. The results obtained indicate that copper ion implantation improves the antibacterial effect and wear behaviour for all the three medical materials studied. However, corrosion resistance decreases after ion implantation of copper. Experimental results indicate that the antibacterial property and corrosion resistance should be balanced for medical titanium materials. The marked deteriorated corrosion resistance of 317 L suggests that copper implantation may not be an effective method of improving its antibacterial activity.

Wan, Y. Z.; Xiong, G. Y.; Liang, H.; Raman, S.; He, F.; Huang, Y.

2007-10-01

250

Rate Processes in Solvent Extraction of Metal Ion  

Microsoft Academic Search

The mechanism and kinetics of metal extraction with several extractants, including chelating agents, acidic organophosphorous extractant and neutral extractants are discussed in this paper.Firstly the extraction rate of metal ion for the general extraction system is formulated by solving the diffusional equation with chemical reaction, in which the interfacial reaction is considered by the boundary conditions. The overall rate expressions

YOSHIKAZU MIYAKE; YOSHINARI BABA

2000-01-01

251

Current and prospective applications of metal ion–protein binding  

Microsoft Academic Search

Since immobilized metal ion affinity chromatography (IMAC) was first introduced, several variants of this method and many other metal affinity-based techniques have been devised. IMAC quickly established itself as a highly reliable purification procedure, showing rapid expansion in the number of preparative and analytical applications while not remaining confined to protein separation. It was soon applied to protein refolding (matrix-assisted

E. K. M Ueda; P. W Gout; L Morganti

2003-01-01

252

Oxidative mechanisms in the toxicity of metal ions  

Microsoft Academic Search

The role of reactive oxygen species, with the subsequent oxidative deterioration of biological macromolecules in the toxicities associated with transition metal ions, is reviewed. Recent studies have shown that metals, including iron, copper, chromium, and vanadium undergo redox cycling, while cadmium, mercury, and nickel, as well as lead, deplete glutathione and protein-bound sulfhydryl groups, resulting in the production of reactive

S. J. Stohs; D. Bagchi

1995-01-01

253

Biosorption of precious metal ions by chicken feather  

Microsoft Academic Search

Chicken feather (C-feather) is an intricate network of stable and water-insoluble protein fibers with high surface area and\\u000a is an abundant bioresource. C-feather protein was found to accumulate various precious metal ions (gold and platinum metals)\\u000a selectively from their dilute aqueous solutions in high yield and in short contact time, depending on pH and characteristics\\u000a of the individual precious metal

Kyozo Suyama; Yoshitaka Fukazawa; Hiroshi Suzumura

1996-01-01

254

High-current-density metal-ion implantation  

Microsoft Academic Search

Design features and preliminary performance data for an ion-implantation system that derives its broad, high-current-density beam directly from a steady, metal-plasma discharge in a high temperature graphite chamber are described. Metal vapor is supplied by drawing electron current to an anode-potential crucible to vaporize a pure metal in it. Argon used to start the discharge is turned off once sufficient

Paul J. Wilbur; Ronghua Wei

1992-01-01

255

Determination of noble metals in Savannah River Site high-level radioactive sludge  

SciTech Connect

High-level radioactive sludge at the Savannah River Site (SRS) will be processed at the Defense Waste Processing Facility (DWPF) into durable borosilicate glass wasteforms. The sludges are analyzed for elemental content before processing to ensure compatibility with the glass-making processes. Noble metal fission products in sludge, can under certain conditions, cause problems in the glass melter. Therefore, reliable noble metal determinations are important. The scheme used to measure noble metals in SRS sludges consists of dissolving sludge with hot aqua regia followed by determinations with inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and ICP-Mass Spectroscopy (ICP-MS) techniques. ICP-MS is the preferred method for measuring trace levels of noble metals in SRS radioactive waste because of superior sensitivity. Analytical results are presented for the two major types of SRS sludge.

Coleman, C.J.; Kinard, W.F.; Bibler, N.E.; Bickford, D.F.; Ramsey, W.G.

1990-12-31

256

A discussion on the application and production of metal ion beams  

Microsoft Academic Search

Metal ion beams, which are used in surface modification of metals and alloys as ion beam micrometallurgy, are promising candidates for advanced applications in semiconductors and insulators. Doping with transition metal and rare-earth metal ions in semiconductors and insulators to form metallic nanoclusters attracted much more attention recently, since their applications in diluted magnetic semiconductors, electroluminescent devices, giant magnetic resistance,

Xiaotang Ren; Ziqiang Zhao; Weijiang Zhao

2008-01-01

257

Surgical Variables Influence Metal Ion Levels After Hip Resurfacing  

Microsoft Academic Search

Background  Metal-on-metal bearings in surface arthroplasty are associated with prolonged periods of elevated ion circulation. However,\\u000a there exists some controversy regarding the effect of different surgical variables on the concentration of metal ions in whole\\u000a blood of patients after hip resurfacing.\\u000a \\u000a \\u000a \\u000a \\u000a Questions\\/purposes  We sought to confirm which clinical and radiographic parameters are associated with elevated levels of cobalt, chromium, and\\u000a molybdenum after

Nicholas M. Desy; Stephane G. Bergeron; Alain Petit; Olga L. Huk; John Antoniou

2011-01-01

258

Ion source metal-arc fault current protection circuit  

SciTech Connect

Ion sources can be damaged by arcs between metallic components of the source if these arcs are permitted to last. The negative-biased low-work-function converter in a surface conversion negative ion source is especially susceptible to metal-arc breakdown damage. Here an electronic circuit for minimizing the damage caused by such an arc is described. The circuit uses a transistor switch and an inductor in series with the converter bias power supply to limit the damage during the metal-arc breakdown.

deVries, G.J.; Lietzke, A.F.; van Os, C.F.A.; Stearns, J.W. (Lawrence Berkeley Laboratory, University of California, Berkeley, California (USA))

1991-12-01

259

Neutralization by metal ions of the toxicity of sodium selenide.  

PubMed

Inert metal-selenide colloids are found in animals. They are believed to afford cross-protection against the toxicities of both metals and selenocompounds. Here, the toxicities of metal salt and sodium selenide mixtures were systematically studied using the death rate of Saccharomyces cerevisiae cells as an indicator. In parallel, the abilities of these mixtures to produce colloids were assessed. Studied metal cations could be classified in three groups: (i) metal ions that protect cells against selenium toxicity and form insoluble colloids with selenide (Ag?, Cd²?, Cu²?, Hg²?, Pb²? and Zn²?), (ii) metal ions which protect cells by producing insoluble metal-selenide complexes and by catalyzing hydrogen selenide oxidation in the presence of dioxygen (Co²? and Ni²?) and, finally, (iii) metal ions which do not afford protection and do not interact (Ca²?, Mg²?, Mn²?) or weakly interact (Fe²?) with selenide under the assayed conditions. When occurring, the insoluble complexes formed from divalent metal ions and selenide contained equimolar amounts of metal and selenium atoms. With the monovalent silver ion, the complex contained two silver atoms per selenium atom. Next, because selenides are compounds prone to oxidation, the stabilities of the above colloids were evaluated under oxidizing conditions. 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB), the reduction of which can be optically followed, was used to promote selenide oxidation. Complexes with cadmium, copper, lead, mercury or silver resisted dissolution by DTNB treatment over several hours. With nickel and cobalt, partial oxidation by DTNB occurred. On the other hand, when starting from ZnSe or FeSe complexes, full decompositions were obtained within a few tens of minutes. The above properties possibly explain why ZnSe and FeSe nanoparticles were not detected in animals exposed to selenocompounds. PMID:23342137

Dauplais, Marc; Lazard, Myriam; Blanquet, Sylvain; Plateau, Pierre

2013-01-14

260

Titanates deliver metal ions to human monocytes.  

PubMed

Amorphous peroxotitantes (APT) are insoluble titanium-based particles that bind a variety of metal compounds with high affinity; these particles could be sequestered locally in a solid phase to deliver metal-based drugs. Previous studies have confirmed the 'biodelivery' of metals from metal-APT complexes to fibroblasts, but not monocytes. Our goal in the current study was to use monocytic cytokine secretion to assess delivery of gold or platinum-based compounds from APT to human THP1 monocytes. Cytokine secretion was not triggered by APT alone or metal-APT complexes. In monocytes activated by lipopolysaccharide (LPS), APT alone enhanced or suppressed IL1beta or IL6 secretion, yet TNFalpha secretion was unaffected. Complexes of APT and Au(III) or cis-platin altered LPS-activated IL6 or IL1beta secretion most, TNFalpha least. Our results suggest that the APT deliver metals to monocytes. PMID:19941042

Wataha, John C; Hobbs, David T; Wong, Jacqueline J; Dogan, Sami; Zhang, Hai; Chung, K-H; Elvington, Mark C

2009-11-26

261

Removal of metal ions from aqueous solution  

DOEpatents

A method of removing heavy metals from aqueous solution, a composition of matter used in effecting said removal, and apparatus used in effecting said removal. One or more of the polypeptides, poly ({gamma}-glutamylcysteinyl)glycines, is immobilized on an inert material in particulate form. Upon contact with an aqueous solution containing heavy metals, the polypeptides sequester the metals, removing them from the solution. There is selectivity of poly ({gamma}-glutamylcysteinyl)glycines having a particular number of monomer repeat units for particular metals. The polypeptides are easily regenerated by contact with a small amount of an organic acid, so that they can be used again to remove heavy metals from solution. This also results in the removal of the metals from the column in a concentrated form.

Jackson, P.J.; Delhaize, E.; Robinson, N.J.; Unkefer, C.J.; Furlong, C.

1988-08-26

262

Metal ion implantation in inert polymers for strain gauge applications  

NASA Astrophysics Data System (ADS)

Metal ion implantation in inert polymers may produce ultra-thin conducting films below the polymer surface. These subsurface films are promising structures for strain gauge applications. To this purpose, polycarbonate substrates were irradiated at room temperature with low-energy metal ions (Cu+ and Ni+) and with fluences in the range between 1 × 1016 and 1 × 1017 ions/cm2, in order to promote the precipitation of dispersed metal nanoparticles or the formation of a continuous thin film. The nanoparticle morphology and the microstructural properties of polymer nanocomposites were investigated by glancing-incidence X-ray diffraction and transmission electron microscopy (TEM) measurements. At lower fluences (<5 × 1016 ions/cm2) a spontaneous precipitation of spherical-shaped metal nanoparticles occurred below the polymer top-surface (˜50 nm), whereas at higher fluences the aggregation of metal nanoparticles produced the formation of a continuous polycrystalline nanofilm. Furthermore, a characteristic surface plasmon resonance peak was observed for nanocomposites produced at lower ion fluences, due to the presence of Cu nanoparticles. A reduced electrical resistance of the near-surface metal-polymer nanocomposite was measured. The variation of electrical conductivity as a function of the applied surface load was measured: we found a linear relationship and a very small hysteresis.

di Girolamo, Giovanni; Massaro, Marcello; Piscopiello, Emanuela; Tapfer, Leander

2010-10-01

263

Assessment of natural radioactivity and heavy metals in water and soil around seismically active area  

Microsoft Academic Search

The natural radioactivity concentration and some heavy metals in various water and soil samples collected from seismically\\u000a active area have been determined. Gross-alpha and beta concentrations of different 33 water samples and some heavy metal (Fe,\\u000a Pb, Cu, K, Mn, Cr and Zn) concentration in 72 soil samples collected from two major fault systems (North and East Anatolian\\u000a Active Fault

Oktay Baykara; Mahmut Do?ru

2010-01-01

264

Treatment and Stabilization of Potentially Pyrophoric Radioactive Metal Chips and Turnings  

Microsoft Academic Search

As part of the continuing mission to decontaminate, decommission, and restore environmental quality at multiple sites throughout the U.S. Department of Energy (US DOE) nuclear complex, approximately 2,000 containers of potentially pyrophoric radioactive metal chips and turnings, weighing over 192,000 kilograms have been identified. These wastes, mostly depleted uranium (DU) and thorium metals, must be treated to remove or immobilize

B. R. Crocker; R. Grondin; T. Yarbrough

2006-01-01

265

Release and efficiencies of radioactive ion beams from the JAEA-ISOL target/ion source systems  

NASA Astrophysics Data System (ADS)

For the ISOL-based radioactive ion beam facility, TRIAC, separation efficiencies and release times of neutron-rich isotopes produced in proton-induced fission of 238U have been measured using the JAEA-ISOL target/ion source systems. With a FEBIAD-B2 type integrated target ion source, for example, we obtained separation yields, the values were normalized to a uranium target thickness of 1 g/cm2 and 1 ?A primary proton beam current, 1.4 × 106 pps for 91Kr, 7 × 105 pps for 126In, 2.6 × 106 pps for 138Xe, respectively. Using a surface ionization type ion source, under the same normalization, the separation yields of 1.8 × 107 pps for 93Rb, 6 × 107 pps for 94Sr, 2.5 × 106 pps for 143Cs and 5 × 106 pps for 142Ba were observed. The release times of radioactive Rb, Cs, Ba, In, Kr and Xe atoms were measured using present target/ion source systems. Comparison of the measured yields of Ba, In and Xe isotopes with the calculated ones suggests that the long release time gave low separation efficiency for short-lived isotopes.

Osa, Akihiko; Matsuda, Makoto; Sato, Tetsuya K.; Ichikawa, Shin-Ichi

2008-10-01

266

Stopping, Trapping and Cooling of Radioactive Fission Fragments in an Ion Catcher Device  

NASA Astrophysics Data System (ADS)

An ion catcher as presented in this contribution is able to create cooled and very clean singly-charged ion pulses out of a ‘hot’ beam within a very short period of time. Precision measurements on shortlived radioactive nuclides become possible. This contribution describes experiments with a 252Cf fission source at the ‘gas-cooler’ at ATLAS (Argonne Tandem Linac Accelerating System) at the Argonne National Laboratories (ANL), Argonne, USA[1]. The system consists of a gas-cell to stop and thermalize the ions, two extraction radio frequency quadrupole structures (RFQ) to separate the ions from the buffer gas and a buncher RFQ to cool and accumulate the ions. The system and its performance is investigated with two independent measurements. The transported activity was measured to determine the efficiency of the system and time of flight measurements (TOF) were performed to determine the transported masses with respect to the transported activity.

Maier, M.; Boudreau, C.; Buchinger, F.; Clark, J. A.; Crawford, J. E.; Dilling, J.; Fukutani, H.; Gulick, S.; Lee, J. K. P.; Moore, R. B.; Savard, G.; Schwartz, J.; Sharma, K. S.

2001-01-01

267

Removal of heavy metal ions from wastewaters: a review.  

PubMed

Heavy metal pollution has become one of the most serious environmental problems today. The treatment of heavy metals is of special concern due to their recalcitrance and persistence in the environment. In recent years, various methods for heavy metal removal from wastewater have been extensively studied. This paper reviews the current methods that have been used to treat heavy metal wastewater and evaluates these techniques. These technologies include chemical precipitation, ion-exchange, adsorption, membrane filtration, coagulation-flocculation, flotation and electrochemical methods. About 185 published studies (1988-2010) are reviewed in this paper. It is evident from the literature survey articles that ion-exchange, adsorption and membrane filtration are the most frequently studied for the treatment of heavy metal wastewater. PMID:21138785

Fu, Fenglian; Wang, Qi

2010-12-08

268

Batch sorption of divalent metal ions onto brown coal  

SciTech Connect

Brown coal, a relatively abundant and inexpensive material is currently being investigated as an adsorbent to remove some contaminants from aqueous solution. The adsorption of some heavy metals from aqueous solutions on the brown coals was studied as a function of pH, contact time, adsorbent dosage and concentration of metal solutions. A carboxyl, phenolic hydroxyl, and metoxyl functional group present on the coal surface was the adsorption site to remove metal ions from solution by means of ion exchange and hydrogen bonding. Effective removal of heavy metals was achieved at pH values of 4.0-5.0. The experimental data have been analyzed using the Langmuir isotherm models. Under optimized conditions, the percentage of metal removal by brown coal adsorption was over 80%.

Pehlivan, E.; Gode, F. [University of Selcuk, Konya (Turkey). Faculty of Engineering & Architecture

2006-12-15

269

Angular Resolved Energy Analysis of (69)Ga+ Ions from a Gallium Liquid Metal Ion Source.  

National Technical Information Service (NTIS)

An analysis system was designed and built to characterize liquid metal ion source beams. Both mass and angular resolved energy distribution measurments can be made, from which both FWHM energy spreads and energy deficits can be obtained, thus making this ...

P. Marriott

1987-01-01

270

Structural modifications in biosynthetic melanins induced by metal ions.  

PubMed

A number of transition metal ions with a wide distribution in biological systems, e.g., Cu2+, Co2+ and Zn2+, are shown to affect markedly the chemical properties of melanins formed by the tyrosinase-catalysed oxidation of dopa. Acid decarboxylation and permanganate degradation provide evidence that melanins prepared in the presence of metal ions contain a high content of carboxyl groups arising from the incorporation of 5,6-dihydroxyindole-2-carboxylic acid (DICA) into the pigment polymer. Naturally occurring melanins from cephalopod ink and B16 mouse melanoma were found to be much more similar to melanins prepared in the presence of metal ions than to standard melanins prepared in the absence of metal ions. These results suggest that the presence of carboxylated indole units in natural melanins is probably due to the intervention in the biochemical pathway of metal ions which, as recently shown, catalyse the formation of DICA versus 5,6-dihydroxyindole in the rearrangement of dopachrome. PMID:3124888

Palumbo, A; d'Ischia, M; Misuraca, G; Prota, G; Schultz, T M

1988-02-17

271

Colored thin films for specific metal ion detection.  

PubMed

This paper describes the investigation of chitosan and poly(allylamine) (PAH) for the creation of a multi-film, color-based dipstick for the detection of metal ions in solution. Thin, colored films of chitosan and PAH cross-linked with hexamethylene 1,6-di(aminocarboxysulfonate) (HDACS) are created where color is due to film thickness and optical interference effects. The films are investigated for their ability to selectively detect aqueous metal ions via changes in thickness and/or color. Chitosan-HDACS films were selective for Cr(VI) over all other metal ions tested including Cr(acac)3 and Cr(NO3)3 x 9H2O, and PAH-HDACS films were selective for Cu(II) and Cu(I) salts over all other metal ions tested. The irreversible, selective changes due to metal ion solutions were not caused by varying the pH. Potomac River water was also tested using the two films, with results indicating the presence of Cu(II) in the aqueous sample. PMID:15382871

Schauer, Caroline L; Chen, Mu-San; Price, Ronald R; Schoen, Paul E; Ligler, Frances S

2004-08-15

272

Physics Prospects from Accelerated Radioactive Ions at CERN  

NASA Astrophysics Data System (ADS)

Through the advent of post-accelerated beams with REX-ISOLDE at CERN, probing nuclear properties using transfer reactions and Coulomb excitation of exotic nuclear species is now possible. REX ISOLDE currently provides beams of energy 2.2 MeV/u (soon be upgraded to 3.1 MeV/u) into the gamma-ray MINIBALL array, and other instrumentation, at the secondary target position. Examples of research topics currently addressed using REX are presented. Scheduled energy up-grades will increase the physics potential even further. The goal for the next five years will be to accelerate ions up to 5 MeV/A and higher energies. Increase of primary beam intensity will also be achieved in a phased approach, with a significant enhancement provided by the proposed Superconducting Proton Linac as the primary accelerator.

Butler, P. A.

2004-03-01

273

Physics prospects from accelerated radioactive ions at CERN  

NASA Astrophysics Data System (ADS)

Through the advent of post-accelerated beams with REX-ISOLDE at CERN, probing nuclear properties using transfer reactions and Coulomb excitation of exotic nuclear species is now possible. REX ISOLDE currently provides beams of energy 2.2 MeV/u (soon be upgraded to 3.1 MeV/u) into the gamma-ray MINIBALL array, and other instrumentation, at the secondary target position. Examples of research topics currently addressed using REX are presented. Scheduled energy up-grades will increase the physics potential even further. The goal for the next five years will be to accelerate ions up to 5 MeV/A and higher energies. Increase of primary beam intensity will also be achieved in a phased approach, with a significant enhancement provided by the proposed Superconducting Proton Linac as the primary accelerator. permanent address: Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE

Butler, P. A.

2004-04-01

274

Metal ion complexation by ionizable crown ethers  

SciTech Connect

Since the last informal progress report, research has been focused upon the synthesis and characterization of novel ionizable multidentate ligands and their application in competitive solvent extraction and liquid membrane transport of alkali metal cations and alkaline earth cations. During the report period, considerable attention has been devoted to obtaining a better understanding of the factors which influence the efficiencies and selectivities of alkali metal cation solvent extraction by lipophilic crown ether carboxylic acids.

Bartsch, R.A.

1986-07-15

275

Use of ion characteristics to predict relative toxicity of mono-, di- and trivalent metal ions: Caenorhabditis elegans LC50  

Microsoft Academic Search

Predictive models for relative toxicity of divalent metal ions using ion characteristics have been produced with both Microtox®, a 15 min microbial bioassay, and the 24 h Caenorhabditis elegans bioassay. Relative toxicity of mono-, di- and trivalent metal ions has also been successfully modeled using ion characteristics with the Microtox® bioassay. This study extends this approach to include longer exposure

Christopher P. Tatara; Michael C. Newman; John T. McCloskey; Phillip L. Williams

1998-01-01

276

Characterization of Chromized Metallic Surfaces by Means of Radioactive Cr  

Microsoft Academic Search

The spatial distribution of Cr deposited on metallic surfaces at concentrations of about 10 at\\/cm was examined by detecting the radiation components emitted in the Cr decay. The autoradiography revealed a non-homogeneous Cr covering. Combined Auger electron and X-ray spectroscopies yielded information on the Cr concentration, especially in the 2 nm thick surface layer. This concentration was found to depend

V. Rö?iger; A. Freyer; E. Hartmann; C. Treutler; V. Brabec; O. Dragoun; A. Kovalik

1986-01-01

277

Emittance characterization of a hot-cavity laser ion source at Holifield Radioactive Ion Beam Facility  

SciTech Connect

The first investigation of the transverse emittance of a hot-cavity laser ion source based on all-solid-state Ti:sapphire lasers is presented. The emittances of {sup 63}Cu ion beams generated by three-photon resonant ionization are measured and compared with that of the {sup 69}Ga and {sup 39}K ion beams resulting from surface ionization in the same ion source. A self-consistent unbiased elliptical exclusion method is adapted for noise reduction and emittance analysis. Typical values of the rms and 90% fractional emittances of the Cu ion beams at 20 keV energy are found to be about 2 and 8 {pi} mm mrad, respectively, for the ion currents of 2-40 nA investigated. The emittances of the laser-produced Cu ion beams are smaller than those of the surface-ionized Ga and K ion beams.

Liu, Y.; Baktash, C.; Beene, J. R.; Havener, C. C.; Krause, H. F.; Schultz, D. R.; Stracener, D. W.; Vane, C. R. [Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Geppert, Ch.; Gottwald, T.; Kessler, T.; Wies, K.; Wendt, K. [Institut fuer Physik, Johannes Gutenberg-Universitaet Mainz, D-55099 Mainz (Germany)

2009-08-15

278

Charge state breeding for the acceleration of radioactive ions at TRIUMF  

SciTech Connect

A 14.5 GHz electron cyclotron resonance ion source (PHOENIX from Pantechnik) has been set up at the Isotope Separation and ACceleration (ISAC) facility at TRIUMF for the charge state breeding of radioactive ions. After extensive testing and optimization on a test bench it has been moved on-line and put into operation. During a first test in 2008 a beam of {sup 80}Rb{sup 14+} was successfully created from {sup 80}Rb{sup 1+} and accelerated by the ISAC postaccelerator. Further tests with different stable and radioactive isotopes from the ISAC on-line sources and from a test source with stable Cs have been carried out. Until now an efficiency of 1.4% for {sup 124}Cs{sup 20+} has been obtained.

Ames, F.; Baartman, R.; Bricault, P.; Jayamanna, K.; McDonald, M. [TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3 (Canada); Lamy, T. [LPSC, CNRS/IN2P3, UJF, 53 Av. des Martyres, 38026 Grenoble (France)

2010-02-15

279

A Negative-Surface Ionization for Generation of Halogen Radioactive Ion Beams  

SciTech Connect

A simple and efficient negative surface ionization source has been designed, fabricated and initially tested for on-line generation of radioactive ion beams of the halogens (Cl, Br, I, and At) for use in the nuclear-structure and nuclear-astrophysics research programs at the Holifield Radioactive Ion Beam Facility. The source utilizes a solid, spherical geometry LaB{sub 6} surface ionizer for forming highly electronegative atoms and molecules. Despite its widely publicized propensity for being easily poisoned, no evidences of this effect were experienced during testing of the source. Nominal efficiencies of 15% for Br{sup {minus}} beam generation were obtained during off-line evaluation of the source with AlBr3 feed material when account is taken of the fractional dissociation of the molecule. Principles of operation, design features, operational parameter data, initial performance results, and beam quality data (emittance) are presented in this article.

Zaim, H.

2001-04-16

280

Liquid-metal ion source study of critical sizes of multiply charged positive ions  

Microsoft Academic Search

LPIS (liquid-metal ion source) results are presented on the critical size above which ions of a given charge state begin to be observed for a given element. Tin and copper are considered, and the critical-size value for copper is interpreted using a simple quantum-mechanical calculation in which the molecular ions are assumed to be compact. The hopping of electrons from

P. Joyes; J. van de Walle

1985-01-01

281

RADIOACTIVE MATERIAL SHIPPING PACKAGINGS AND METAL TO METAL SEALS FOUND IN THE CLOSURES OF CONTAINMENT VESSELS INCORPORATING CONE SEAL CLOSURES  

SciTech Connect

The containment vessels for the Model 9975 radioactive material shipping packaging employ a cone-seal closure. The possibility of a metal-to-metal seal forming between the mating conical surfaces, independent of the elastomer seals, has been raised. It was postulated that such an occurrence would compromise the containment vessel hydrostatic and leakage tests. The possibility of formation of such a seal has been investigated by testing and by structural and statistical analyses. The results of the testing and the statistical analysis demonstrate and procedural changes ensure that hydrostatic proof and annual leakage testing can be accomplished to the appropriate standards.

Loftin, B; Glenn Abramczyk, G; Allen Smith, A

2007-06-06

282

The radioactive ion beam project at VECC, Kolkata Its present status and future plans  

NASA Astrophysics Data System (ADS)

A project to build an ISOL type radioactive ion beam facility has been undertaken at Variable Energy Cyclotron Centre, Kolkata. The status of RIB facility being built at VECC is presented. Stable ion beams of 30 keV/u have already been accelerated with very high efficiency through the RFQ. The completion of the accelerator system to 400 keV/u is expected in 2007. A second phase for production of neutron-rich RIB through photo-fission route and further acceleration of RI beams using Linacs up to about 6 7 MeV/u is under consideration.

Chakrabarti, A.

2007-08-01

283

The radioactive ion beam project at VECC, Kolkata -A status report  

NASA Astrophysics Data System (ADS)

A project to build an ISOL-post accelerator type of radioactive ion beam (RIB) facility has been undertaken at VECC, Kolkata. The funding for the first phase of the project was approved in August 1997. This phase will be the R&D phase and will be completed by December 2003. The present status of development of the various sub-systems of the RIB facility will be discussed.

Chakrabarti, Alok

2002-12-01

284

Bisnitronyl nitroxides bridged by tetra(ethyleneoxy) sensing metal ions spectroscopically and electrochemically  

Microsoft Academic Search

Compound 1 containing two nitronyl nitroxide units bridged by tetra(ethyleneoxy) was designed and synthesized for sensing metal ions, by taking the features of nitronyl nitroxides: a chromophore showing absorption in visible range, reversible oxidation\\/reduction and coordination to metal ions. The absorption spectrum of 1 was altered markedly upon mixing with a few rare earth metal ions and some transition metal

Yanxin Yu; Deqing Zhang; Guanxin Zhang; Zhiyong Wang; Daoben Zhu

2006-01-01

285

Process for Removal of Heavy-Metal Ions from Waste Water (Japanese Patent).  

National Technical Information Service (NTIS)

A process for removal of heavy-metal ions from waste water is characterized by the fact that a waste water containing heavy-metal ions is brought into contact with active ferrite to adsorb the heavy-metal ions, followed by desorption of the heavy-metal io...

S. Goto T. Nagura

1983-01-01

286

Adsorbent for metal ions and method of making and using  

SciTech Connect

A method comprises the step of spray-drying a solution or slurry comprising (alkali metal or ammonium) (metal) hexacyanoferrate particles in a liquid, to provide monodisperse, substantially spherical particles in a yield of at least 70 percent of theoretical yield and having a particle size in the range of 1 to 500 micrometers, said particles being active towards Cs ions. The particles, which can be of a single salt or a combination of salts, can be used free flowing, in columns or beds, or entrapped in a nonwoven, fibrous web or matrix or a cast porous membrane, to selectively remove Cs ions from aqueous solutions.

White, L.R.; Lundquist, S.H.

2000-07-25

287

Determination of metal ions in biological purification of waste waters  

SciTech Connect

Chromium, nickel, copper, zinc, and manganese were determined in active sludge extracted for utilization from sewage purification works in biological purification of waste waters. The measurements were carried out by the atomic absorption method and with Merck colorimetric kits for rapid determination of metal ions. The results obtained by the rapid colorimetric method agree fairly well with those obtained by the atomic absorption method, which makes it possible to recommend rapid colorimetric methods for routine analysis of biological objects for the content of ions of heavy metals.

Tikhomirova, L.N.; Spiridonova, N.N.; Mandzhgaladze, I.D. [Moscow State Correspondence Inst. of the Food Industry, Moscow (Russian Federation)] [and others

1994-12-01

288

Adsorbent for metal ions and method of making and using  

DOEpatents

A method comprises the step of spray-drying a solution or slurry comprising (alkali metal or ammonium) (metal) hexacyanoferrate particles in a liquid, to provide monodisperse, substantially spherical particles in a yield of at least 70 percent of theoretical yield and having a particle size in the range of 1 to 500 micrometers, said particles being active towards Cs ions. The particles, which can be of a single salt or a combination of salts, can be used free flowing, in columns or beds, or entrapped in a nonwoven, fibrous web or matrix or a cast porous membrane, to selectively remove Cs ions from aqueous solutions.

White, Lloyd R. (Minneapolis, MN); Lundquist, Susan H. (White Bear Township, MN)

1999-01-01

289

Adsorbent for metal ions and method of making and using  

DOEpatents

A method comprises the step of spray-drying a solution or slurry comprising (alkali metal or ammonium) (metal) hexacyanoferrate particles in a liquid, to provide monodisperse, substantially spherical particles in a yield of at least 70 percent of theoretical yield and having a particle size in the range of 1 to 500 micrometers, said particles being active towards Cs ions. The particles, which can be of a single salt or a combination of salts, can be used free flowing, in columns or beds, or entrapped in a nonwoven, fibrous web or matrix or a cast porous membrane, to selectively remove Cs ions from aqueous solutions. 2 figs.

White, L.R.; Lundquist, S.H.

1999-08-10

290

Adsorbent for metal ions and method of making and using  

DOEpatents

A method comprises the step of spray-drying a solution or slurry comprising (alkali metal or ammonium) (metal) hexacyanoferrate particles in a liquid, to provide monodisperse, substantially spherical particles in a yield of at least 70 percent of theoretical yield and having a particle size in the range of 1 to 500 micrometers, said particles being active towards Cs ions. The particles, which can be of a single salt or a combination of salts, can be used free flowing, in columns or beds, or entrapped in a nonwoven, fibrous web or matrix or a cast porous membrane, to selectively remove Cs ions from aqueous solutions.

White, Lloyd R. (Minneapolis, MN); Lundquist, Susan H. (White Bear Township, MN)

2000-01-01

291

Metal-ion recycle technology for metal electroplating waste waters  

Microsoft Academic Search

As a result of a collaboration with Boeing Aerospace, the authors have begun a program to identify suitable treatments or to develop new treatments for electroplating baths. The target baths are mixed-metal or alloy baths that are being integrated into the Boeing electroplating complex. These baths, which are designed to replace highly toxic chromium and cadmium baths, contain mixtures of

N. N. Sauer; B. F. Smith

1993-01-01

292

Broad-beam multi-ampere metal ion source  

SciTech Connect

An embodiment of the MEVVA (metal vapor vacuum arc) high current metal ion source has been developed in which the beam is formed from a 10-cm diameter set of extractor grids and which produces a peak beam current of up to several Amperes. The source, MEVVA V, operates in a pulsed mode with a pulse width at present 0.25 ms and a repetition rate of up to several tens of pulses per second (power supply limited). The multicathode feature that was developed for the prior source version, MEVVA IV, has been incorporated here also; one can switch between any of 18 separate cathodes and thus metallic beam species. Maximum beam extraction voltage is over 90 kV, and since the ion charge state typically from Q = 1 to 5, depending on the metal employed, the ion energy in the extracted beam can thus be up to several hundred keV. This source is a new addition to the MEVVA family of metal ion sources, and we are at present investigating the operational regimes and the limits to the source performance. In this paper we describe the source and present some preliminary results. 10 refs., 4 figs.

Brown, I.G.; Galvin, J.E.; MacGill, R.A.; Paoloni, F.J. (Lawrence Berkeley Lab., CA (USA); Wollongong Univ. (Australia). Dept. of Electrical Engineering)

1989-06-01

293

What Happens to Serum Metal Ion Levels After a Metal-on-Metal Bearing is Removed?  

PubMed

Serum cobalt (Co) and chromium (Cr) levels are commonly used to screen for excessive wear of metal-on-metal hip replacements. However, it is unknown how rapidly these should decline after revision. 25 patients with average Co and Cr ion levels of 56.3?g/L and 20.5?g/L were followed with serial ion level testing post-revision. Over the first 6weeks post-revision, the rate of decline for Co and Cr was approximately 2% per day and this slowed to approximately 1% decline per day over the ensuing 6weeks. This translated to a decline of approximately 80% from the starting value after 6weeks and a decline of approximately 90% after 12weeks post-revision. The rate of decline for both Co and Cr was significantly faster during the first 6weeks (P<0.001). In patients with ultra-high Cr levels>20?g/L, the rate of Cr decline is less predictable and may be protracted leading to persistent elevation above 5?g/L for one year or more post-revision in some cases. PMID:23948123

Ball, Scott T; Severns, Dustyn; Linn, Michael; Meyer, R Scott; Swenson, F Craig

2013-08-12

294

Improved scales for metal ion softness and toxicity.  

PubMed

Ten scales relating to chemical hardness or softness of metal ions were compiled. These included eight published scales such as those of Pearson, Ahrland, Klopman, and Misono. Another scale consisted of the logs of the solubility products of metal sulfides, and yet another was a consensus scale constructed from -log K values for metal ion binding to seven soft ligands. These 10 scales were normalized and averaged. The resulting consensus scale for softness (sigma(Con)) appeared to be superior to any of the 10 scales used in its construction based on correlations among the scales. Other possible indicators of softness were examined, including the standard electrode potential (E(0)) and the bulk metal density (rho(Metal)), both of which were also superior to most of the 10 scales just mentioned. Vales for sigma(Con) may be computed from E(0), rho(Metal), and the first ionization potential (I(P)), R(2) = 0.867, for the equation sigma(Con) = aE(0)I(P) + brho(Metal). A consensus scale for toxicity (T(Con)) derived from studies with many different taxa correlated well (R(2) = 0.807) with sigma(Con) computed from the preceding equation, but incorporation of ion charge (Z) into the following equation, T(Con) = asigma(Con) + bsigma(Con)Z + cZ, increased R(2) to 0.923. Substitution of other softness scales for sigma(Con) into equations to predict T(Con) reduced the value of R(2). Thus, sigma(Con) appears to be a superior scale for metal ion softness and toxicity, the latter being an interactive function of both softness and charge. PMID:18980392

Kinraide, Thomas B

2008-11-03

295

Adsorption of Metal Ions and Metal Complexes on Clay Minerals: A Study of the Nature of Bonding by X-Ray Photoelectron Spectroscopy.  

National Technical Information Service (NTIS)

Results are reported of an investigation of the interaction of metal ions, metal ion complexes, and organic ligands with mineral and metal ion-saturated surfaces. Minerals studied include those with oxidizing and nonoxidizing surfaces (for example, lead, ...

J. G. Dillard A. B. Emerson M. H. Koppelman D. L. Crowther C. V. Schenck

1982-01-01

296

Smart responsive microcapsules capable of recognizing heavy metal ions.  

PubMed

Smart responsive microcapsules capable of recognizing heavy metal ions are successfully prepared with oil-in-water-in-oil double emulsions as templates for polymerization in this study. The microcapsules are featured with thin poly(N-isopropylacrylamide-co-benzo-18-crown-6-acrylamide) (P(NIPAM-co-BCAm)) membranes, and they can selectively recognize special heavy metal ions such as barium(II) or lead(II) ions very well due to the "host-guest" complexation between the BCAm receptors and barium(II) or lead(II) ions. The stable BCAm/Ba(2+) or BCAm/Pb(2+) complexes in the P(NIPAM-co-BCAm) membrane cause a positive shift of the volume phase transition temperature of the crosslinked P(NIPAM-co-BCAm) hydrogel to a higher temperature, and the repulsion among the charged BCAm/Ba(2+) or BCAm/Pb(2+) complexes and the osmotic pressure within the P(NIPAM-co-BCAm) membranes result in the swelling of microcapsules. Induced by recognizing barium(II) or lead(II) ions, the prepared microcapsules with P(NIPAM-co-BCAm) membranes exhibit isothermal and significant swelling not only in outer and inner diameters but also in the membrane thickness. The proposed microcapsules in this study are highly attractive for developing smart sensors and/or carriers for detection and/or elimination of heavy metal ions. PMID:20656104

Pi, Shuo-Wei; Ju, Xiao-Jie; Wu, Han-Guang; Xie, Rui; Chu, Liang-Yin

2010-05-31

297

Nuclear and Astro Physics at the Center of Excellence for Radioactive Ion Beam Studies for Stewardship Science  

NASA Astrophysics Data System (ADS)

Neutron transfer reactions with radioactive ion beams of atomic nuclei have been used to probe the shell structure of nuclei far from stability and provide information important to understanding the origin of the elements heavier than iron.

Cizewski, Jolie A.

2010-10-01

298

Nuclear and Astro Physics at the Center of Excellence for Radioactive Ion Beam Studies for Stewardship Science  

SciTech Connect

Neutron transfer reactions with radioactive ion beams of atomic nuclei have been used to probe the shell structure of nuclei far from stability and provide information important to understanding the origin of the elements heavier than iron.

Cizewski, Jolie A. [Department of Physics and Astronomy, 136 Frelinghuysen Road, Piscataway, New Jersey 08854-8019 (United States)

2010-10-11

299

Heavy metal ions are potent inhibitors of protein folding  

SciTech Connect

Environmental and occupational exposure to heavy metals such as cadmium, mercury and lead results in severe health hazards including prenatal and developmental defects. The deleterious effects of heavy metal ions have hitherto been attributed to their interactions with specific, particularly susceptible native proteins. Here, we report an as yet undescribed mode of heavy metal toxicity. Cd{sup 2+}, Hg{sup 2+} and Pb{sup 2+} proved to inhibit very efficiently the spontaneous refolding of chemically denatured proteins by forming high-affinity multidentate complexes with thiol and other functional groups (IC{sub 50} in the nanomolar range). With similar efficacy, the heavy metal ions inhibited the chaperone-assisted refolding of chemically denatured and heat-denatured proteins. Thus, the toxic effects of heavy metal ions may result as well from their interaction with the more readily accessible functional groups of proteins in nascent and other non-native form. The toxic scope of heavy metals seems to be substantially larger than assumed so far.

Sharma, Sandeep K. [Biochemisches Institut, Universitaet Zuerich, CH-8057 Zuerich (Switzerland); Departement de Biologie Moleculaire Vegetale, Universite de Lausanne, CH-1015 Lausanne (Switzerland); Goloubinoff, Pierre [Departement de Biologie Moleculaire Vegetale, Universite de Lausanne, CH-1015 Lausanne (Switzerland); Christen, Philipp [Biochemisches Institut, Universitaet Zuerich, CH-8057 Zuerich (Switzerland)], E-mail: christen@bioc.uzh.ch

2008-07-25

300

Adsorption characteristics of metal ions on chitosan chemically modified by D-galactose  

SciTech Connect

The adsorption characteristics of metal ions on chitosan chemically modified by D-galactose were examined. The pH dependency on the distribution ratio was found to be affected by the valency of the metal ion, and the apparent adsorption equilibrium constants of the metal ions were determined. The order of adsorption of the metal ions is Ga > In > Nd > Eu for the trivalent metal ions and Cu > Ni > Co for the divalent metal ions. It is believed that amino and hydroxyl groups in the chitosan act as a chelating ligand.

Kondo, Kazuo; Sumi, Hisaharu; Matsumoto, Michiaki [Doshisha Univ., Tanabe, Kyoto (Japan)

1996-07-01

301

A discussion on the application and production of metal ion beams.  

PubMed

Metal ion beams, which are used in surface modification of metals and alloys as ion beam micrometallurgy, are promising candidates for advanced applications in semiconductors and insulators. Doping with transition metal and rare-earth metal ions in semiconductors and insulators to form metallic nanoclusters attracted much more attention recently, since their applications in diluted magnetic semiconductors, electroluminescent devices, giant magnetic resistance, etc. In this paper, some experiments for metal ion beams will be presented, and various methods and technologies for the production of metal ion beams will be discussed. PMID:18315270

Ren, Xiaotang; Zhao, Ziqiang; Zhao, Weijiang

2008-02-01

302

A discussion on the application and production of metal ion beams  

NASA Astrophysics Data System (ADS)

Metal ion beams, which are used in surface modification of metals and alloys as ion beam micrometallurgy, are promising candidates for advanced applications in semiconductors and insulators. Doping with transition metal and rare-earth metal ions in semiconductors and insulators to form metallic nanoclusters attracted much more attention recently, since their applications in diluted magnetic semiconductors, electroluminescent devices, giant magnetic resistance, etc. In this paper, some experiments for metal ion beams will be presented, and various methods and technologies for the production of metal ion beams will be discussed.

Ren, Xiaotang; Zhao, Ziqiang; Zhao, Weijiang

2008-02-01

303

A discussion on the application and production of metal ion beams  

SciTech Connect

Metal ion beams, which are used in surface modification of metals and alloys as ion beam micrometallurgy, are promising candidates for advanced applications in semiconductors and insulators. Doping with transition metal and rare-earth metal ions in semiconductors and insulators to form metallic nanoclusters attracted much more attention recently, since their applications in diluted magnetic semiconductors, electroluminescent devices, giant magnetic resistance, etc. In this paper, some experiments for metal ion beams will be presented, and various methods and technologies for the production of metal ion beams will be discussed.

Ren Xiaotang; Zhao Ziqiang; Zhao Weijiang [Institute of Heavy Ion Physics, Peking University, Beijing, 100871 (China) and Key Laboratory of Heavy Ion Physics (Peking University), Ministry of Education, Beijing 100871 (China)

2008-02-15

304

DUHOCAMIS: A dual hollow cathode ion source for metal ion beams  

NASA Astrophysics Data System (ADS)

In this paper we describe a novel ion source named DUHOCAMIS for multiply charged metal ion beams. This ion source is derived from the hot cathode Penning ion gauge ion source (JINR, Dubna, 1957). A notable characteristic is the modified Penning geometry in the form of a hollow sputter electrode, coaxially positioned in a compact bottle-magnetic field along the central magnetic line of force. The interaction of the discharge geometry with the inhomogeneous but symmetrical magnetic field enables this device to be operated as hollow cathode discharge and Penning discharge as well. The main features of the ion source are the very high metal ion efficiency (up to 25%), good operational reproducibility, flexible and efficient operations for low charged as well as highly charged ions, compact setup, and easy maintenance. For light ions, e.g., up to titanium, well-collimated beams in the range of several tens of milliamperes of pulsed ion current (1 ms, 10/s) have been reliably performed in long time runs.

Zhao, W. J.; Müller, M. W. O.; Janik, J.; Liu, K. X.; Ren, X. T.

2008-02-01

305

DUHOCAMIS: a dual hollow cathode ion source for metal ion beams.  

PubMed

In this paper we describe a novel ion source named DUHOCAMIS for multiply charged metal ion beams. This ion source is derived from the hot cathode Penning ion gauge ion source (JINR, Dubna, 1957). A notable characteristic is the modified Penning geometry in the form of a hollow sputter electrode, coaxially positioned in a compact bottle-magnetic field along the central magnetic line of force. The interaction of the discharge geometry with the inhomogeneous but symmetrical magnetic field enables this device to be operated as hollow cathode discharge and Penning discharge as well. The main features of the ion source are the very high metal ion efficiency (up to 25%), good operational reproducibility, flexible and efficient operations for low charged as well as highly charged ions, compact setup, and easy maintenance. For light ions, e.g., up to titanium, well-collimated beams in the range of several tens of milliamperes of pulsed ion current (1 ms, 10/s) have been reliably performed in long time runs. PMID:18315181

Zhao, W J; Müller, M W O; Janik, J; Liu, K X; Ren, X T

2008-02-01

306

Potential uses of silica-bonded macrocyclic ligands for separation of metal ions from nuclear waste  

SciTech Connect

This paper explores the potential of a relatively new separation material that is obtained by covalently binding macrocyclic ligands to silica gel. Fortunately, neutral macrocyclic ligands can be bound to silica gel such that metal binding constants do not differ significantly from the binding constants of the free ligands so that selectivities of free macrocyclic ligands can be used in designing silica-bound materials with appropriate selectivities. Accordingly, macrocyclic ligands known to have selectivities for Pd{sup +2}, Ag{sup +}, Ru{sup +3}, Sr{sup +2}, and Cs{sup +} were covalently bound to silica gel. These materials were then tested for their ability to separate these ions from a synthetic test solution representative of a nuclear process waste stream. Cs{sup +} and Sr{sup +2} are of interest because their radioactive isotopes are major radioactive constituents of defense nuclear wastes accumulated at the Hanford site. Removal of precious metals such as Pd{sup +2}, Ag{sup +} and Ru{sup +3} present in nuclear defense waste are of interest not just because of their obvious economic value, but also because these metals may hinder the waste vitrification process for confining radionuclides.

Bruening, R.L. (IBC Advanced Technologies, Inc., Provo, UT (United States)); Camaioni, D.M.; Colton, N.G.; Morrey, J.R. (Pacific Northwest Lab., Richland, WA (United States))

1991-11-01

307

A concept for emittance reduction of DC radioactive heavy-ion beams  

SciTech Connect

Numerical simulations indicate that it should be possible to use an electron beam to strip 1+ DC radioactive ion beams to 2+ or higher charge states with on the order of 50% efficiency. The device, which the authors call an Electron-Beam Charge-State Amplifier, is similar to an Electron Beam Ion Source, except that it is not pulsed, the beams are continuous. The 2+ beams are obtained in a single pass through a magnetic solenoid while higher charge states may be reached via multiple passes. An unexpected result of the ion optics simulations is that the normalized transverse emittance of the ion beam is reduced in proportion to the charge-state gain. Ion beams with realistic emittances and zero angular momentum relative to the optic axis before entering the solenoid will travel though the solenoid on helical orbits which intercept the axis once per cycle. With an ion beam about 2 mm in diameter and an electron beam about 0.2 mm in diameter, the ion stripping only occurs very near the optic axis, resulting in the emittance reduction.

Nolen, J.A.; Dooling, J.C.

1995-06-01

308

Proteins and protein-rich biomass as environmentally friendly adsorbents selective for precious metal ions.  

PubMed

Proteins exhibit specific interactions with various metal ions, which play important roles in a living cell. Here, we found that various proteins selectively adsorbed precious metal ions at a wide range of pH values. Studies on protein sequences and on synthesized peptides revealed that a histidine-containing sequence had specific interactions with precious metal ions (Au3+ and Pd2+). We then investigated a few types of protein-rich biomass as adsorbents for precious metal ions. In the presence of various transition metal ions, Au3+ and Pd2+ were also selectively adsorbed onto the biomass tested. The bound precious metal ions were recovered by aqua regia after charring the metal-bound biomass. Finally, we demonstrated the successful recovery of Au3+ and Pd2+ from a metal refining solution and a metal plating waste using the biomass. We propose an environmentally friendly recycling system for precious metal ions using protein-rich biomass. PMID:17593742

Maruyama, Tatsuo; Matsushita, Hironari; Shimada, Yukiko; Kamata, Ichiro; Hanaki, Misa; Sonokawa, Saori; Kamiya, Noriho; Goto, Masahiro

2007-02-15

309

Metal ion bombardment of onion skin cell wall  

SciTech Connect

Ion bombardment of living cellular material is a novel subfield of ion beam surface modification that is receiving growing attention from the ion beam and biological communities. Although it has been demonstrated that the technique is sound, in that an adequate fraction of the living cells can survive both the vacuum environment and energetic ion bombardment, there remains much uncertainty about the process details. Here we report on our observations of onion skin cells that were subjected to ion implantation, and propose some possible physical models that tend to support the experimental results. The ion beams used were metallic (Mg, Ti, Fe, Ni, Cu), mean ion energy was typically 30keV, and the implantation fluence was in the range 1014 1016 ions/cm2. The cells were viewed using Atomic Force Microscopy, revealing the formation of microcrater-like structures due to ion bombardment. The implantation depth profile was measured with Rutherford backscattering spectrometry and compared to the results of the TRIM, T-DYN and PROFILE computer codes.

Sangyuenyongpipat, S.; Vilaithong, T.; Yu, L.D.; Verdaguer, A.; Ratera, I.; Ogletree, D.F.; Monteiro, O.R.; Brown, I.G.

2004-05-10

310

Search for new physics with neutrinos at radioactive ion beam facilities  

NASA Astrophysics Data System (ADS)

We propose applications of radioactive ion beam facilities to investigate physics beyond the Standard Model. In particular, we focus upon the search for sterile neutrinos and the possible measurement of coherent neutrino-nucleus scattering, by means of a low-energy beta beam with a Lorentz boost factor ??1. In both cases, we consider Li8 and B8 ions as neutrino sources. In the considered setup, the collected radioactive ions are sent inside a 4? detector. For the first application, we provide the number of events associated with neutrino-nucleus coherent scattering, when the detector is filled with a noble liquid. For the sterile search, we consider that the spherical detector is filled with a liquid scintillator, and that the neutrino detection channel is inverse beta decay. We provide the exclusion curves for the sterile neutrino mixing parameters, based upon the 3+1 formalism, depending upon the achievable ion intensity. Our results are obtained both from total rates, and by including spectral information with binning in energy and in distance. The proposed experiment represents a possible alternative to clarify the current anomalies observed in neutrino experiments.

Espinoza, Catalina; Lazauskas, Rimantas; Volpe, Cristina

2012-12-01

311

Electropositive bivalent metallic ion unsaturated polyester complexed polymer concrete  

DOEpatents

Quick setting polymer concrete compositions are described which are mixtures of unsaturated polyesters and crosslinking monomers together with appropriate initiators and promoters in association with aggregate which may be wet and a source of bivalent metallic ions which will set to polymer concrete with excellent structural properties.

Sugama, T.; Kukacka, L.E.; Horn, W.H.

1983-05-13

312

ANION EXCHANGE SEPARATIONS OF METAL IONS IN PARTIALLY NONAQUEOUS SOLUTIONS  

Microsoft Academic Search

A systematic approach to anion exchange in partially nonaqueous solvents ; was initiated. Distribution coefficicients of metal ions for Dowex 1 X8, ; chloride form resin in organic solvent-water mixtures containing hydrochloric ; acid were measured. The organic solvents used were methyl alcohol, ethyl ; alcohol, isopropyl alcohol, acetone, and dioxane. When the organic solvent ; concentration was increased and

D. J. Pietrzyk; J. S. Fritz

1960-01-01

313

Electrostatic Force Microscopy of Metallic Ion-Intercalated DNA  

NASA Astrophysics Data System (ADS)

The local charge of plasmid DNA has been studied using electrostatic force microscopy (EFM). The sample was prepared by immersing plasmid DNA in ZnCl2. The interaction of the tip with the positive local charge was stronger for the DNA immersed in a solution of higher concentration, and this phenomenon was evidence of the positive metallic ion intercalation into DNA.

Jeon, Dongryul; Kim, Chaeho; Son, Jung Min; Lee, Nam Joo; Kang, Chi Jung; Kim, Yong-Sang

2006-01-01

314

Parameters influencing flotation in removal of metal ions  

Microsoft Academic Search

In this paper the main parameters affecting the flotation process, like reagents (collector, frother, flocculant, etc.) and feed concentrations, pH value of the solution, ionic strength, gas flowrate and bubbles size, as applied to the separation of heavy metals and from dilute aqueous solutions, hydro?metallurgical or environmental origin, are examined. The flotation methods used, in laboratory scale, were ion, precipitate

A. I. Zouboulis; K. A. Matis; G. A. Stalidis

1990-01-01

315

Accumulation of heavy-metal ions by Zoogloea ramigera  

Microsoft Academic Search

Biomass has been produced from glucose using the organism Zoogloea ramigera 115. This biomass has been used to remove copper, cadmium, and uranyl ions from water solutions. The metal uptake was studied with two different methods: either by spectrophotometric measurements on the solutions after flocculation or by potentiometric measurements with amalgam electrodes in order to follow the entire complex formation.

Anders B. Norberg; Hans Persson

1984-01-01

316

Carboxylation of scleroglucan for controlled crosslinking by heavy metal ions  

Microsoft Academic Search

Samples of carboxylated scleroglucan, sclerox, with a degree of carboxylation in the side-chains varying from 10 to 50% were made in order to investigate the potential of using carboxylation as a means to control subsequent gelation by heavy metal ions. The storage and loss moduli of aqueous solutions of sclerox samples as a function of time were determined at T

Bjørn T. Stokke; Arnljot Elgsaeter; Olav Smidsrød; Bjørn E. Christensen

1995-01-01

317

COAGULATION AND PRECIPITATION OF SELECTED METAL IONS FROM AQUEOUS SOLUTIONS  

EPA Science Inventory

The report gives results of laboratory jar tests to develop data on the removal from aqueous solution of 12 metal ions of environmental concern. The project, of very limited scope, provides initial screening data only: coagulants were evaluated at only two dose levels (1.1 and 1....

318

Ion Beam Mixing in Binary Amorphous Metallic Alloys.  

National Technical Information Service (NTIS)

Ion beam mixing (IM) was measured in homogeneous amorphous metallic alloys of Cu-Er and Ni-Ti as a function of temperature using tracer impurities, i.e., the so-called ''marker geometry''. In Cu-Er, a strong temperature dependence in IM was observed betwe...

H. Hahn R. S. Averback T. Diaz de la Rubia P. R. Okamoto

1985-01-01

319

Diane Oligomers: Heat Resistance Increase by Metal Ions  

Microsoft Academic Search

Examination has been made of the possibility of increasing the heat resistance of diane oligomers by means of the introduction of Cu, Co, or Ni ions into the polymer matrix. This was carried out by the hardening of epoxy oligomers with chelates of metals and aliphatic amines. The properties of polymers produced and their dependence on the quantity and structure

A. V. Kurnoskin

1991-01-01

320

Theory of electron spin resonance of magnetic ions in metals  

Microsoft Academic Search

Reviewed at both a relatively elementary and more advanced level is the interpretative theory of the electron spin resonance of magnetic ions in metals. The various theoretical possibilities are illustrated by experimental examples wherever possible. Initially the development is based upon the Bloch-Hasegawa equations. The relationship of the advanced theory to this more elementary theory is emphasized. Multimagnetic-impurity experiments, the

S. E. Barnes

1981-01-01

321

Ion mobility studies of electronically excited states of atomic transition metal cations: Development of an ion mobility source for guided ion beam experiments  

Microsoft Academic Search

The design of an ion mobility source developed to couple to a guided ion beam tandem mass spectrometer is presented. In these\\u000a exploratory studies, metal ions are created continuously by electron ionization of the volatile hexacarbonyls of the three\\u000a group 6 transition metals. These ions are focused into a linear hexapole ion trap, which collects the ions and then creates

Christopher Iceman; Chad Rue; Robert M. Moision; Barun K. Chatterjee; P. B. Armentrout

2007-01-01

322

Cooling of short-lived, radioactive, highly charged ions with the TITAN cooler Penning trap. Status and perspectives  

NASA Astrophysics Data System (ADS)

TITAN is an on-line facility dedicated to precision experiments with short-lived radioactive isotopes, in particular mass measurements. The achievable resolution on mass measurement, which depends on the excitation time, is limited by the half life of the radioactive ion. One way to bypass this is by increasing the charge state of the ion of interest. TITAN has the unique capability of charge-breeding radioactive ions using an electron-beam ion trap (EBIT) in combination with Penning trap mass spectrometry. However, the breeding process leads to an increase in energy spread, ? E, which in turn negatively influences the mass uncertainty. We report on the development of a cooler Penning trap which aims at reducing the energy spread of the highly charged ions prior to injection into the precision mass measurement trap. Electron and proton cooling will be tested as possible routes. Mass selective cooling techniques are also envisioned.

Simon, V. V.; Delheij, P.; Dilling, J.; Ke, Z.; Shi, W.; Gwinner, G.

2011-07-01

323

Precipitation of alkylbenzene sulfonates with metal ions  

SciTech Connect

The precipitation domains of P-(1-methylnonyl)benzene sulfonate ions with Li/sup +/, Na/sup +/, K/sup +/, Ca/sup 2 +/, Mg/sup 2 +/, Al/sup 3 +/, and La/sup 3 +/ and of Ca/sup 2 +/-P-(hexyloctyl)benzene sulfonate have been determined at constant pH and 25 C. The linear solubility boundaries reverse their slope at the critical micellar concentration of the surfactant. A semiquantitative interpretation of the data is offered. The properties of the solids formed also are described. 18 references.

Peacock, J.M.; Matijevic, E.

1980-10-01

324

Quadrupole ion trap studies of the structure and reactivity of transition metal ion pair complexes  

PubMed

Ion pairs are common species observed in the electrospray mass spectra of transition metal coordination complexes. To understand the nature of these ion pairs, a systematic study of the gas-phase chemistry of these species using ion-molecule reactions and collision-induced dissociation (CID) was carried out. Ion pair complexes of the type MLnX+ (where M is Mn(II), Fe(II), Co(II), Ni(II), Cu(II) or Zn(II), L is 1,10-phenanthroline, 2,2'-bipyridine, ethylenediamine, diethylenetriamine or 1,4,8,11-tetraazacyclotetradecane and X is Cl-, NO3-, acetylacetonate, ClO4-, acetate or SCN-) were studied. Ion-molecule reactions can distinguish whether the counterion in an ion pair is an inner- or outer-sphere ligand and can determine the coordination mode of the counterion. In addition, CID and ion-molecule reactions reveal some interesting chemistry of these complexes and unique coordination modes for some of the anions studied here were inferred from the ion-molecule reactions. For example, the thiocyanate ion is found to coordinate in a bidentate fashion in Zn(II) and Ni(II) complexes, contrasting behavior typically observed in solution. Also, certain Co(II) and Fe(II) ion pair complexes undergo oxidation reactions in which species such as dioxygen and nitric oxide from the counterions ClO4- and NO3- are transferred to the Co(II) and Fe(II) complexes, showing the inherent affinity of these metals for these molecules. These complexes were also studied by ion-molecule reactions and CID. Dioxygen in complexes formed by CID is demonstrated to be bidentate, suggesting the formation of a peroxo ligand with concurrent oxidation of the metal. PMID:10767759

Vachet; Callahan

2000-03-01

325

Electrospray Ionization Mass Spectrometry: From Cluster Ions to Toxic metal Ions in Biology  

SciTech Connect

This dissertation focused on using electrospray ionization mass spectrometry to study cluster ions and toxic metal ions in biology. In Chapter 2, it was shown that primary, secondary and quarternary amines exhibit different clustering characteristics under identical instrument conditions. Carbon chain length also played a role in cluster ion formation. In Chapters 3 and 4, the effects of solvent types/ratios and various instrumental parameters on cluster ion formation were examined. It was found that instrument interface design also plays a critical role in the cluster ion distribution seen in the mass spectrum. In Chapter 5, ESI-MS was used to investigate toxic metal binding to the [Gln{sup 11}]-amyloid {beta}-protein fragment (1-16). Pb and Cd bound stronger than Zn, even in the presence of excess Zn. Hg bound weaker than Zn. There are endless options for future work on cluster ions. Any molecule that is poorly ionized in positive ion mode can potentially show an increase in ionization efficiency if an appropriate anion is used to produce a net negative charge. It is possible that drug protein or drug/DNA complexes can also be stabilized by adding counter-ions. This would preserve the solution characteristics of the complex in the gas phase. Once in the gas phase, CID could determine the drug binding location on the biomolecule. There are many research projects regarding toxic metals in biology that have yet to be investigated or even discovered. This is an area of research with an almost endless future because of the changing dynamics of biological systems. What is deemed safe today may show toxic effects in the future. Evolutionary changes in protein structures may render them more susceptible to toxic metal binding. As the understanding of toxicity evolves, so does the demand for new toxic metal research. New instrumentation designs and software make it possible to perform research that could not be done in the past. What was undetectable yesterday will become routine tomorrow.

Nicholas B. Lentz

2007-12-01

326

Does metal ion complexation make radical clocks run fast?  

PubMed

Ab initio molecular orbital and density functional calculations at the CBS-RAD(QCISD,B3-LYP) level for Li+ and at B3LYP for Na+, K+, Cu+,and Ag+ reveal that the barrier to ring-closure of the 1-hexen-6-yl ("Delta(5)-hexenyl") radical to the cyclopentylmethyl radical, a so-called radical clock reaction, is decreased very significantly by complexation of the double bond to metal cations. This barrier lowering should occur on complexation with many metal ions, as shown by calculations on all of the monovalent ions listed above. Additional density functional calculations including explicit solvation of the model system complexed to the lithium ion with tetrahydrofuran suggest that the effect found is not limited to the gas phase but may also be significant in experimental radical clock reactions in solution, even for lithium. PMID:12603171

Horn, Anselm H C; Clark, Timothy

2003-03-01

327

Vibronic intensities in the electronic spectra of transition metal ions  

NASA Astrophysics Data System (ADS)

The electric dipole vibronic intensities due to the three odd parity vibrational modes of the 4A2g ? 4T1g(t2e) transition of the octahedral complex ion MnF62- have been evaluated using a combination of crystal field and ligand polarization methods. Several different force fields and radial functions have been employed. For the ligand polarization term, coupling of the induced ligand dipole to both the metal electric quadrupole and the electric hexadecapole are considered. Whilst the crystal field and these two ligand polarization contributions to the total vibronic intensity are all within a factor of ten, they each contribute to different vibronic origins. This shows that for this ion it is not sufficient to truncate the expansion of the metal ion electric multipole moment at the leading term.

Acevedo, R.; Flint, C. D.

328

Method for removing metal ions from solution with titanate sorbents  

SciTech Connect

A method for removing metal ions from solution comprises the steps of providing titanate particles by spray-drying a solution or slurry comprising sorbent titanates having a particle size up to 20 micrometers, optionally in the presence of polymer free of cellulose functionality as binder. The sorbent is active towards heavy metals from Periodic Table (CAS version) Groups IA, IIA, IB, IIB, IIIB, and VIII, to provide monodisperse, substantially spherical particles in a yield of at least 70% of theoretical yield which have a particle size distribution in the range of 1 to 500 micrometers. The particles can be used free flowing in columns or beds, or entrapped in a nonwoven, fibrous web or matrix or a cast porous membrane, to selectively remove metal ions from aqueous or organic liquid.

Lundquist, S.H.; White, L.R.

1999-11-23

329

Method for removing metal ions from solution with titanate sorbents  

DOEpatents

A method for removing metal ions from solution comprises the steps of providing titanate particles by spray-drying a solution or slurry comprising sorbent titanates having a particle size up to 20 micrometers, optionally in the presence of polymer free of cellulose functionality as binder, said sorbent being active towards heavy metals from Periodic Table (CAS version) Groups IA, IIA, IB, IIB, IIIB, and VIII, to provide monodisperse, substantially spherical particles in a yield of at least 70 percent of theoretical yield and having a particle size distribution in the range of 1 to 500 micrometers. The particles can be used free flowing in columns or beds, or entrapped in a nonwoven, fibrous web or matrix or a cast porous membrane, to selectively remove metal ions from aqueous or organic liquid.

Lundquist, Susan H. (White Bear Township, MN); White, Lloyd R. (Minneapolis, MN)

1999-01-01

330

Dissociation of gas-phase dimeric complexes of lactic acid and transition-metal ions formed under electrospray ionization conditions; the role of reduction of the metal ion.  

PubMed

Dimeric complex ions of the type [M(A-H)A]+, where M=metal ion (Co, Ni, Cu, and Zn) and A=ligand (lactic acid, methyl lactate or ethyl lactate), were generated in the gas phase under electrospray ionization conditions. The collision-induced dissociation spectra of [M(A-H)A]+ ions were recorded to study the behaviour of ligand and metal ions in decomposition of these dimeric complex ions. Based on the fragmentation pathways observed for complex ions of lactic acid, it is found that both the carboxylic and hydroxyl groups of lactic acid are involved in the complex formation following displacement of a proton by the metal ion. The dimeric complex ions of Co, Ni, and Zn dissociated to yield similar types of ions, whereas that of Cu behaved differently. The dissociations of Co-, Ni-, and Zn-bound dimeric complexes involved losses of neutral molecules while keeping the oxidation state of the metal ion unchanged. However, elimination of radicals is found in the dissociation of dimeric complex ions of Cu, and the oxidation state of copper is reduced from Cu(II) to Cu(I) in the resulting fragment ions. The deprotonated ligand is involved in the fragmentation pathway of Cu complexes, whereas it is intact in other complexes. The oxidation state of the metal ion, nature of the ligand, and site of attachment to the metal ion are found to control the dissociation of these dimeric complex ions. PMID:15593065

Kumar, M Ravi; Prabhakar, S; Kumar, M Kiran; Reddy, T Jagadeshwar; Vairamani, M

2005-01-01

331

Metal-on-metal bearings total hip arthroplasty: the cobalt and chromium ions release concern.  

PubMed

With certain concerns recently reported on metal-on-metal bearing couples in total hip arthroplasty, this study's objective is to review the current knowledge concerning release of metal ions and its potential consequences. Each metal-on-metal implant presents different tribological properties. The analytical techniques for metals are accurate and the Co ion rates seem acceptable up to 2 ?g/L. A delayed type IV hypersensitivity reaction (atypical lymphocytic vasculitis-associated lesion [ALVAL]) may be the source of arthroplasty failure. Idiosyncratic, it remains unpredictable even using cutaneous tests and apparently is rare (0.3%). Today, there are no scientific or epidemiologic data supporting a risk of carcinogenesis or teratogenesis related to the use of a metal-on-metal bearings couple. Solid pseudotumors nearly exclusively are observed with resurfacing procedures, carrying a high annual revision rate in women under 40 years of age, occurring particularly in cases of acetabular malposition and with use of cast molded Cr-Co alloys. Osteolysis manifests through complete and progressive radiolucent lines or through cavitary lesions stemming from ALVAL-type alterations or impingement problems or implant incompatibility. The formation of wear debris exceeding the biological tolerance is possible with implant malposition, subluxation, and jamming of the femoral head in cases of cup deformity. Moreover, each implant presents different metal ion production; assessment of their performance and safety is required before their clinical use. With the knowledge available today, metal-on-metal bearing couples are contraindicated in cases of metal allergies or end stage renal dysfunction and small size resurfacing should cautiously be used. PMID:20832379

Delaunay, C; Petit, I; Learmonth, I D; Oger, P; Vendittoli, P A

2010-09-15

332

Development and properties of crystalline silicotitanate (CST) ion exchangers for radioactive waste applications  

SciTech Connect

Crystalline silicotitanates (CSTs) are a new class of ion exchangers that were jointly invented by researchers at Sandia National Laboratories and Texas A&M University. One particular CST, known as TAM-5, is remarkable for its ability to separate parts-per-million concentrations of cesium from highly alkaline solutions (pH> 14) containing high sodium concentrations (>5M). It is also highly effective for removing cesium from neutral and acidic solutions, and for removing strontium from basic and neutral solutions. Cesium isotopes are fission products that account for a large portion of the radioactivity in waste streams generated during weapons material production. Tests performed at numerous locations with early lab-scale TAM-5 samples established the material as a leading candidate for treating radioactive waste volumes such as those found at the Hanford site in Washington. Thus Sandia developed a Cooperative Research and Development Agreement (CRADA) partnership with UOP, a world leader in developing, commercializing, and supplying adsorbents and associated process technology to commercialize and further develop the material. CSTs are now commercially available from UOP in a powder (UOP IONSIV{reg_sign} IE-910 ion exchanger) and granular form suitable for column ion exchange operations (UOP IONSIV{reg_sign} IE-911 ion exchanger). These materials exhibit a high capacity for cesium in a wide variety of solutions of interest to the Department of Energy, and they are chemically, thermally, and radiation stable. They have performed well in tests at numerous sites with actual radioactive waste solutions, and are being demonstrated in the 100,000 liter Cesium Removal Demonstration taking place at Oak Ridge National Laboratory with Melton Valley Storage Tank waste. It has been estimated that applying CSTs to the Hanford cleanup alone will result in a savings of more than $300 million over baseline technologies.

Miller, J.E.; Brown, N.E.

1997-04-01

333

Chitosan removes toxic heavy metal ions from cigarette mainstream smoke  

NASA Astrophysics Data System (ADS)

This study investigated the removal of heavy metal ions from cigarette mainstream smoke using chitosan. Chitosan of various deacetylation degrees and molecular weights were manually added to cigarette filters in different dosages. The mainstream smoke particulate matter was collected by a Cambridge filter pad, digested by a microwave digestor, and then analyzed for contents of heavy metal ions, including As(III/V), Pb(II), Cd(II), Cr(III/VI) and Ni(II), by graphite furnace atomic absorption spectrometry (GFAAS). The results showed that chitosan had a removal effect on Pb(II), Cd(II), Cr(III/VI) and Ni(II). Of these, the percent removal of Ni(II) was elevated with an increasing dosage of chitosan. Chitosan of a high deace tylation degree exhibited good binding performance toward Cd(II), Cr(III/VI) and Ni(II), though with poor efficiency for Pb(II). Except As(III/V), all the tested metal ions showed similar tendencies in the growing contents with an increasing chitosan molecular weight. Nonetheless, the percent removal of Cr(III/VI) peaked with a chitosan molecular weight of 200 kDa, followed by a dramatic decrease with an increasing chitosan molecular weight. Generally, chitosan had different removal effects on four out of five tested metal ions, and the percent removal of Cd(II), Pb(II), Cr(III/VI) and Ni(II) was approximately 55%, 45%, 50%, and 16%, respectively. In a word, chitosan used in cigarette filter can remove toxic heavy metal ions in the mainstream smoke, improve cigarette safety, and reduce the harm to smokers.

Zhou, Wen; Xu, Ying; Wang, Dongfeng; Zhou, Shilu

2013-09-01

334

Nuclear Structure Studies with Radioactive Ion Beams in the Mass A = 80 Region  

SciTech Connect

An experimental program to measure spectroscopic properties of neutron-rich nuclei in the A = 80 region is underway at the Holifield Radioactive Ion Beam Facility. Our approach has been to get a comprehensive picture of the shell structure in this region by studying a series of properties of low lying states (E(2{sup +}), B(E2), g-factors and quadrupole moments). The beams, instrumentation and techniques developed specifically for this purpose have allowed us to systematically study the behavior of these observables along isotopic and isotonic chains using both stable and radioactive nuclei under almost identical experimental conditions. We have developed many techniques and detectors for in-beam gamma spectroscopy with radioactive ion beams. Most of the detectors can be used individually or in combination. Generally these detector systems have very large efficiencies. We give examples of their use from three recent experiments; namely, Coulomb excitation of n-rich nuclei along the N = 50 shell closure, the static quadrupole moment of the first 2{sup +} in {sup 78}Ge and g-factor measurements of n-rich isotopes near N = 50.

Galindo-Uribarri, A.; Beene, J. R.; Lagergren, K. B.; Mueller, P. E.; Radford, D. C.; Stracener, D. W.; Varner, R. L.; Yu, C.-H. [Physics Division, Oak Ridge National Laboratory, Oak Ridge TN 37831 (United States); Padilla-Rodal, E. [Instituto de Ciencias Nucleares, UNAM, Mexico City 04510 (Mexico); Batchelder, J. C. [UNIRIB, Oak Ridge Associated Universities, Oak Ridge TN 37831 (United States); Urrego-Blanco, J. P. [Department of Physics and Astronomy, University of Tennessee, Knoxville TN 37996 (United States)

2009-03-10

335

Nuclear Structure Studies with Radioactive Ion Beams in the Mass A = 80 Region  

SciTech Connect

An experimental program to measure spectroscopic properties of neutron-rich nuclei in the A = 80 region is underway at the Holifield Radioactive Ion Beam Facility. Our approach has been to get a comprehensive picture of the shell structure in this region by studying a series of properties of low lying states (E (2+), B (E2), g-factors and quadrupole moments). The beams, instrumentation and techniques developed specifically for this purpose have allowed us to systematically study the behavior of these observables along isotopic and isotonic chains using both stable and radioactive nuclei under almost identical experimental conditions. We have developed many techniques and detectors for in-beam gamma spectroscopy and decay studies with radioactive ion beams. Most of the detectors can be used individually or in combination. Generally these detector systems have very large efficiencies. We give examples of their use from three recent experiments; namely, Coulomb excitation of n-rich nuclei along the N = 50 shell closure, the static quadrupole moment of the first 2+ in 78Ge and g-factor measurements of n-rich isotopes near N = 50.

Galindo-Uribarri, Alfredo {nmn} [ORNL; Padilla, E. [ORNL/Instituto de Ciencias Nucleares, UNAM, Mexico; Batchelder, J. C. [Oak Ridge Associated Universities (ORAU); Beene, James R [ORNL; Lagergren, Karin B [ORNL; Mueller, Paul Edward [ORNL; Radford, David C [ORNL; Stracener, Daniel W [ORNL; Urrego-Blanco, J. P. [University of Tennessee, Knoxville (UTK); Varner Jr, Robert L [ORNL; Yu, Chang-Hong [ORNL

2009-01-01

336

High intensity metal ion beam production with ECR ion sources atthe Lawrence Berkeley National Laboratory  

SciTech Connect

The large number of different experiments performed at the 88 Inch Cyclotron requires great variety and flexibility in the production of ion beams. This flexibility is provided by the two high performance electron cyclotron resonance (ECR) ion sources, the LBL ECR and the AECR-U, which can produce beams of ions as light as hydrogen and as heavy as uranium. With these two sources, up to six different metals can be preloaded using two types of ovens. The ovens are mounted radially on the ion sources and inject the metal vapor though the open sextupole structure into the plasma chamber. For the superconducting ECR ion source VENUS, which is under construction at Lawrence Berkeley National Laboratory, the use of radial ovens is no longer possible, because the magnetic structure is closed radially. Therefore, we are developing two new axial oven types for low and high temperature applications. Metal ion beam production in ECR ion sources using the oven technique is discussed. The design of the axial oven is presented. Finally, the efficiency of the axial oven is compared with the radial oven for the production of Ca.

Wutte, D.; Abbott, S.; Leitner, M.A.; Lyneis, C.M.

2001-09-01

337

Solution NMR refinement of a metal ion bound protein using metal ion inclusive restrained molecular dynamics methods.  

PubMed

Correctly calculating the structure of metal coordination sites in a protein during the process of nuclear magnetic resonance (NMR) structure determination and refinement continues to be a challenging task. In this study, we present an accurate and convenient means by which to include metal ions in the NMR structure determination process using molecular dynamics (MD) simulations constrained by NMR-derived data to obtain a realistic and physically viable description of the metal binding site(s). This method provides the framework to accurately portray the metal ions and its binding residues in a pseudo-bond or dummy-cation like approach, and is validated by quantum mechanical/molecular mechanical (QM/MM) MD calculations constrained by NMR-derived data. To illustrate this approach, we refine the zinc coordination complex structure of the zinc sensing transcriptional repressor protein Staphylococcus aureus CzrA, generating over 130 ns of MD and QM/MM MD NMR-data compliant sampling. In addition to refining the first coordination shell structure of the Zn(II) ion, this protocol benefits from being performed in a periodically replicated solvation environment including long-range electrostatics. We determine that unrestrained (not based on NMR data) MD simulations correlated to the NMR data in a time-averaged ensemble. The accurate solution structure ensemble of the metal-bound protein accurately describes the role of conformational sampling in allosteric regulation of DNA binding by zinc and serves to validate our previous unrestrained MD simulations of CzrA. This methodology has potentially broad applicability in the structure determination of metal ion bound proteins, protein folding and metal template protein-design studies. PMID:23609042

Chakravorty, Dhruva K; Wang, Bing; Lee, Chul Won; Guerra, Alfredo J; Giedroc, David P; Merz, Kenneth M

2013-04-23

338

Lithium Liquid Metal Ion Source Suitable for High Voltage Terminal Applications.  

National Technical Information Service (NTIS)

Liquid metal ion sources offer potential improvement in lateral resolution over conventionally used gaseous sources for MeV microprobe applications because of their intrinsic brightness. The use of a Li liquid metal ion source is particularly attractive b...

P. M. Read J. T. Maskrey G. D. Alton

1989-01-01

339

Liquid metal ion source and alloy for ion emission of multiple ionic species  

DOEpatents

A liquid metal ion source and alloy for the simultaneous ion evaporation of arsenic and boron, arsenic and phosphorus, or arsenic, boron and phosphorus. The ionic species to be evaporated are contained in palladium-arsenic-boron and palladium-arsenic-boron-phosphorus alloys. The ion source, including an emitter means such as a needle emitter and a source means such as U-shaped heater element, is preferably constructed of rhenium and tungsten, both of which are readily fabricated. The ion sources emit continuous beams of ions having sufficiently high currents of the desired species to be useful in ion implantation of semiconductor wafers for preparing integrated circuit devices. The sources are stable in operation, experience little corrosion during operation, and have long operating lifetimes.

Clark, Jr., William M. (Thousand Oaks, CA); Utlaut, Mark W. (Saugus, CA); Wysocki, Joseph A. (Oxnard, CA); Storms, Edmund K. (Los Alamos, NM); Szklarz, Eugene G. (Los Alamos, NM); Behrens, Robert G. (Los Alamos, NM); Swanson, Lynwood W. (McMinnville, OR); Bell, Anthony E. (McMinnville, OR)

1987-06-02

340

New Metal Niobate and Silicotitanate Ion Exchangers: Development and Characterization  

SciTech Connect

This renewal proposal outlines our current progress and future research plans for ion exchangers: novel metal niobate and silicotitanate ion exchangers and their ultimate deployment in the DOE complex. In our original study several forms (including Cs exchanged) of the heat treated Crystalline Silicotitanates (CSTs) were fully characterized by a combination of high temperature synthesis and phase identification, low temperature synthesis and phase identification, and thermodynamics. This renewal proposal is predicated on work completed in our current EMSP program: we have shown preliminary data of a novel class of niobate-based molecular sieves (Na/Nb/M/O, M = transition metals), which show exceptionally high selectivity for divalent cations under extreme conditions (acid solutions, competing cations), in addition to novel silicotitanate phases which are also selective for divalent cations. Furthermore, these materials are easily converted by a high temperature in-situ heat treatment into a refractory ceramic waste form with low cation leachability. The new waste form is a perovskite phase, which is also a major component of Synroc, a titanate ceramic waste form used for sequestration of HLW wastes from reprocessed, spent nuclear fuel. These new niobate ion exchangers also shown orders of magnitude better selectivity for Sr2+ under acid conditions than any other material. The goal of the program is to reduce the costs associated with divalent cation waste removal and disposal, to minimize the risk of contamination to the environment during ion exchanger processing, and to provide DOE with materials for near-term lab-bench stimulant testing, and eventual deployment. The proposed work will provide information on the structure/property relationship between ion exchanger frameworks and selectivity for specific ions, allowing for the eventual ''tuning'' of framework for specific ion exchange needs. To date, DOE sites have become interested in on-site testing of these materials; ongoing discussions and initial experiments are occurring with Dr. Dean Peterman, Idaho National Engineering and Environmental Laboratory (INEEL) (location of the DOE/EM Waste Treatment Focus Area), and Dr. John Harbour, Savannah River Site (SRS). Yet the materials have not been optimized, and further research and development of the novel ion exchangers and testing conditions with simulants are needed. In addition, studies of the ion exchanger composition versus ion selectivity, ion exchange capacity and durability of final waste form are needed. This program will bring together three key institutions to address scientific hurdles of the separation process associated with metal niobate and silicotitanate ion exchangers, in particular for divalent cations (e.g., Sr2+). The program involves a joint effort between researchers at Pacific Northwest National Laboratory, who are leaders in structure/property relations in silicotitanates and in waste form development and performance assessment, Sandia National Laboratories, who discovered and developed crystalline silicotitanate ion exchangers (with Texas A&M and UOP) and also the novel class of divalent metal niobate ion exchangers, and the Thermochemistry Facility at UC Davis, who are world renowned experts in calorimetry and have already performed extensive thermodynamic studies on silicotitanate materials. In addition, Dr. Rodney Ewing of University of Michigan, an expert in radiation effects on materials, and Dr. Robert Roth of the National Institute of Standards and Technology and The Viper Group, a leader in phase equilibria development, will be consultants for radiation and phase studies. The research team will focus on three tasks that will provide both the basic research necessary for the development of highly selective ion exchange materials and also materials for short-term deployment within the DOE complex: (1) Structure/property relationships of a novel class of niobate-based molecular sieves (Na/Nb/M/O, M = transition metals), which show exceptionally high selectivity for divalent cations un

Alexandra Navrotsky; Mary Lou Balmer; Tina M. Nenoff; Yali Su

2003-12-05

341

Status of the MEVVA (Metal Vapor Vacuum Arc) high current metal ion source. [Metal Vapor Vacuum Arc  

SciTech Connect

The MEVVA (Metal Vapor Vacuum Arc) ion source that has been developed at LBL was reported on for the first time at the 1985 Particle Accelerator Conference (1). This source can produce hundreds of milliamperes of beam current of metal species from lithium up to uranium. In the period since then we have developed the source further, and this work is summarized here. We have now run the source with over 30 different beam species, and with an extraction voltage up to 110 kV. We have made and operated a miniature source, the MicroMEVVA. A multi-cathode version, in which one can switch rapidly between cathodes of different materials, has recently been constructed and tested. Applications of the source include: as a synchrotron ion source, as an ion source for heavy ion fusion, and for metallurgical ion implantation; we have done some preliminary work in these directions.

Brown, I.G.; Galvin, J.E.; MacGill, R.A.; Wright, R.T.

1987-03-01

342

Scientific program of the Radioactive Ion Beams Facility in Brasil (RIBRAS)  

NASA Astrophysics Data System (ADS)

The RIBRAS facility (Radioactive Ion Beams in Brasil) is installed in connection with the 8MV Pelletron tandem of the University of São Paulo Physics Institute. It consists of two superconducting solenoids which focalize light radioactive secondary beams of low energy, produced by transfer reactions. Recent experimental results include the elastic scattering and transfer reactions of 6He halo nucleus on 9Be, 27Al, 51V and 120Sn targets. The elastic scattering and transfer of 8Li and 7Be on several targets is also being studied. The transfer reaction 8Li(p,?)5He of astrophysical interest was also studied in the E=0.2-2.5MeV energy range.

Lépine-Szily, A.; Lichtenthäler, R.; Guimarães, V.; Mendes, D. R.; de Faria, P. N.; Barioni, A.; Benjamim, E. A.; Pires, K. C. C.; Morcelle, V.; Condori, R. Pampa; Morais, M. C.; Descouvemont, P.; Moro, A. M.; Rodríguez Gallardo, M.; Assunção, M. M.; Alcantara Nunez, J. A.; Shorto, J. M. B.; Zamora, J. C.; Leistenschneider, E.; Lima, C. E. F.

2010-03-01

343

Modeling (p, xn) reactions producing proton-rich nuclides for radioactive ion beam studies  

SciTech Connect

Over the last few years, an intense worldwide interest has grown in the use of radioactive ion beams (RIB) to study the properties of nuclei far from stability. The relatively recent technological developments that have enabled the production of high-quality radioactive beams promise to lead to a renaissance in nuclear structure and nuclear reaction physics as well as in nuclear astrophysics. Some of the principal issues that will be addressed with RIB research are as follows: (1) the nature of residual interactions, particularly among valence nucleons, in orbitals not accessible near stability, (2) new nuclear shapes and collectivities, (3) neutron halos for extreme NIZ rations, (4) properties of N = Z nuclei far from stability, (5) nuclear reaction mechanisms sensitive to new nuclear structure properties in RIB nuclei, and (6) study of astrophysical nuclear reactions, for the first time, involving unstable nuclei in nucleosynthesis.

Chadwick, M.B.; Young, P.G. [Los Alamos National Lab., NM (United States)

1997-12-01

344

Field-emission liquid-metal ion source and triode ion gun  

Microsoft Academic Search

A pointed-filament-type field-emission liquid-metal ion source is designed and employed as a gold ion source. By adding a crossbar across a hairpin bend, the amount of the gold adhering on the filament is increased. The lifetime is estimated to be over 200 h at 10-?A emission current. The emission current increases with increasing extraction voltage up to a saturation value

Masanori Komuro; Hisazo Kawakatsu

1981-01-01

345

Ion-molecule clusters involving doubly charged metal ions (M2+)  

Microsoft Academic Search

Doubly charged metal ion-ligand L clusters, M2+ (L)n, where M2+ = Mg2+, Ca2+, Sr2+, Ba2+, Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+, can be produced in the gas phase by electrospray of solutions of chloride, bromide or nitrate salts of M2+ in methanol-water. L may be added to the solution or to the gas phase. The ions produced by electrospray at

Arthur T. Blades; Palitha Jayaweera; Michael G. Ikonomou; Paul Kebarle

1990-01-01

346

Peptide immobilisation on porous silicon surface for metal ions detection  

NASA Astrophysics Data System (ADS)

In this work, a Glycyl-Histidyl-Glycyl-Histidine (GlyHisGlyHis) peptide is covalently anchored to the porous silicon PSi surface using a multi-step reaction scheme compatible with the mild conditions required for preserving the probe activity. In a first step, alkene precursors are grafted onto the hydrogenated PSi surface using the hydrosilylation route, allowing for the formation of a carboxyl-terminated monolayer which is activated by reaction with N-hydroxysuccinimide in the presence of a peptide-coupling carbodiimide N-ethyl- N'-(3-dimethylaminopropyl)-carbodiimide and subsequently reacted with the amino linker of the peptide to form a covalent amide bond. Infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy are used to investigate the different steps of functionalization. The property of peptides to form stable complexes with metal ions is exploited to achieve metal-ion recognition by the peptide-modified PSi-based biosensor. An electrochemical study of the GlyHisGlyHis-modified PSi electrode is achieved in the presence of copper ions. The recorded cyclic voltammograms show a quasi-irreversible process corresponding to the Cu(II)/Cu(I) couple. The kinetic factors (the heterogeneous rate constant and the transfer coefficient) and the stability constant of the complex formed on the porous silicon surface are determined. These results demonstrate the potential role of peptides grafted on porous silicon in developing strategies for simple and fast detection of metal ions in solution.

Sam, Sabrina S.; Chazalviel, Jean-Noël Jn; Gouget-Laemmel, Anne Chantal Ac; Ozanam, François F.; Etcheberry, Arnaud A.; Gabouze, Nour-Eddine N.

2011-06-01

347

Development of radioactive ion beam production systems for Tokai Radioactive Ion Acceleration Complex-High temperature ion source for short-lived isotopes  

NASA Astrophysics Data System (ADS)

We have developed a new ion source system in the isotope separator on-line at Japan Atomic Energy Agency, for separation of short-lived isotopes produced by proton-induced fission of 238U. The ion source system is a forced electron beam induced arc discharge version E type ion source with a target container. We successfully operated this system at 2000 °C as a result of reductions in volume of the ion source and the target container, introduction of heating method by electron bombardment, and improvement to the heat shield. This new ion source system was tested using 238U of 640 mg/cm2 with a proton primary beam of 30 MeV, 350 nA. Release times were measured for Kr, In, and Xe. The values of release times are 2.6 s for Kr, 1.8 s for In, and 4.6 s for Xe. In this work, the ion source system enabled us to mass-separate short-lived isotopes such as 93Kr(T1/2=1.286 s), 129In(T1/2=0.61 s), and 141Xe(T1/2=1.73 s) with intensity of 103 ions/s.

Otokawa, Y.; Osa, A.; Sato, T. K.; Matsuda, M.; Ichikawa, S.; Jeong, S. C.

2010-02-01

348

Single-metal-ion-based molecular building blocks (MBBs) approach to the design and synthesis of metal–organic assemblies  

Microsoft Academic Search

The single-metal-ion-based molecular building blocks (MBBs) approach for the construction of metal–organic assemblies, in which hetero-coordinated single metal ions are rendered rigid and directional via nitrogen–oxygen chelation with judiciously selected ligands, has been implemented. Single-metal-ion-based MBBs of the general formula MNx(CO2)y constitute the building units of metal–organic frameworks (MOFs) and metal–organic polyhedra (MOPs) presented herein. The octahedral MBB, MN2(CO2)4, can

Jacilynn A. Brant; Yunling Liu; Dorina F. Sava; Derek Beauchamp; Mohamed Eddaoudi

2006-01-01

349

Rhodobacter capsulatus porphobilinogen synthase, a high activity metal ion independent hexamer  

Microsoft Academic Search

BACKGROUND: The enzyme porphobilinogen synthase (PBGS), which is central to the biosynthesis of heme, chlorophyll and cobalamins, has long been known to use a variety of metal ions and has recently been shown able to exist in two very different quaternary forms that are related to metal ion usage. This paper reports new information on the metal ion independence and

David W. Bollivar; Cheryl Clauson; Rachel Lighthall; Siiri Forbes; Bashkim Kokona; Robert Fairman; Lenka Kundrat; Eileen K. Jaffe

2004-01-01

350

Gold Nanoparticle-Based Sensing of “Spectroscopically Silent” Heavy Metal Ions  

Microsoft Academic Search

A simple colorimetric technique for the detection of small concentrations of aqueous heavy metal ions, including toxic metals such as lead, cadmium, and mercury, is described. Functionalized gold nanoparticles are aggregated in solution in the presence of divalent metal ions by an ion-templated chelation process; this causes an easily measurable change in the absorption spectrum of the particles. The aggregation

Youngjin Kim; Robert C. Johnson; Joseph T. Hupp

2001-01-01

351

Multivariate Correlations Between Properties of Metal Ions and Their Acute Toxicity in Mice.  

National Technical Information Service (NTIS)

This paper extends our earlier study of correlations of acute metal-ion toxicity (14-day LD50) in mice and physicochemical properties of the ions. Here we put metal ions into two main groups as defined by Kaiser. Using most of the metals in the periodic s...

J. E. Turner M. W. Williams B. E. Hingerty T. L. Hayden

1986-01-01

352

Determination of metal ion content of beverages and estimation of target hazard quotients: a comparative study  

Microsoft Academic Search

BACKGROUND: Considerable research has been directed towards the roles of metal ions in nutrition with metal ion toxicity attracting particular attention. The aim of this study is to measure the levels of metal ions found in selected beverages (red wine, stout and apple juice) and to determine their potential detrimental effects via calculation of the Target Hazard Quotients (THQ) for

Theresa Hague; Andrea Petroczi; Paul LR Andrews; James Barker; Declan P Naughton

2008-01-01

353

DETERMINATION OF METAL IONS IN WATER, SOIL, AND SEDIMENT BY CAPILLARY ELECTROPHORESIS  

Microsoft Academic Search

The determination of metal ions in the environmental samples by capillary electrophoresis is an important area for the environmental chemists. The determination of metal ions in water, soil and sediment samples by capillary electrophoresis is reviewed. Various aspects of analysis such as sample pre-treatment, metal ion complexation, detection, choice of visualizing agents, detection limit and choice of electrolytes have been

Imran Ali; Hassan Y. Aboul-Enein

2002-01-01

354

Structurally colored biopolymer thin films for detection of dissolved metal ions in aqueous solution  

Microsoft Academic Search

Natural polymers, such as the polysaccharides alginate and chitosan, are noted sorbents of heavy metals. Their polymer backbone structures are rich in ligands that can interact with metal ions through chelation, electrostatics, ion exchange and nonspecific mechanisms. These water-soluble biopolymer materials can be processed into hydrogel thin films, creating high surface area interfaces ideal for binding and sequestering metal ions

Matthew David Cathell

2008-01-01

355

[Study on protein separation using immobilized metal ion affinity chromatography].  

PubMed

Immobilized metal ion affinity chromatography (IMAC) has shown promise of isolating desired proteins from a mixture based on their difference of affinity for chelated metal ions. With its technological superiority, such as large adsorption capacity, mild separation condition, simple ligands and wide applications, IMAC has become powerful tool for biotechnological products separation, such as proteins, amino acids and gene products. In spite of many sophisticated applications for IMAC, the theoretical analysis of Immobilized metal chromatography has remained insufficient. In this paper, the eluted efficiencies of bovine serum albumin (BSA) in a single-component system under different elution conditions are studied. The effects of several elution factors, such as pH value, ammonium concentration and anion species on protein separation are studied. Comparing the elution data of BSA in IDA-Cu and IDA-Zn columns, the different ability of affinity between metal ions and proteins is found. In addition, the elution behaviors of different proteins are investigated. This work facilitates the further research in separation of real systems. PMID:11051827

Sun, X D; Li, H Q; Sui, H Y; Shen, Z Y

2000-07-01

356

Adsorption of heavy metal ions to floc-type biosorbents.  

PubMed

Adsorption of cadmium and lead ions to floc-type biosorbents was reported in this work. Two types of biosorbents containing a marine microalga, Heterosigma akashiwo (Hada) Hada, or a purple non-sulfur bacterium, Rhodobacter sphaeroides, were prepared. The micro-organisms inactivated by steam sterilization were immobilized in casein floc and cross-linked with glutaraldehyde. In the present immobilizing method, we obtained the biosorbents comprising as much as 67% of micro-organism on a dry-weight basis. Simple metal-binding models were applied to explain the adsorption mechanism of bivalent metal ions to the biosorbents. The results showed that casein acted as both the immobilizing material and the adsorbent material. The adsorption of bivalent metal ions to the biosorbents was due to bidentate binding to the acidic sites on casein and monodentate binding to the acidic sites on micro-organisms. The metal-binding constants and the binding capacities of micro-organisms were scarcely influenced by immobilization. PMID:16290600

Seki, Hideshi; Suzuki, Akira

2002-05-15

357

New Catalytic DNA Biosensors for Radionuclides and Metal ion  

SciTech Connect

We aim to develop new DNA biosensors for simultaneous detection and quantification of bioavailable radionuclides, such as uranium, technetium, and plutonium, and metal contaminants, such as lead, chromium, and mercury. The sensors will be highly sensitive and selective. They will be applied to on-site, real-time assessment of concentration, speciation, and stability of the individual contaminants before and during bioremediation, and for long-term monitoring of DOE contaminated sites. To achieve this goal, we have employed a combinatorial method called “in vitro selection” to search from a large DNA library (~ 1015 different molecules) for catalytic DNA molecules that are highly specific for radionuclides or other metal ions through intricate 3-dimensional interactions as in metalloproteins. Comprehensive biochemical and biophysical studies have been performed on the selected DNA molecules. The findings from these studies have helped to elucidate fundamental principles for designing effective sensors for radionuclides and metal ions. Based on the study, the DNA have been converted to fluorescent or colorimetric sensors by attaching to it fluorescent donor/acceptor pairs or gold nanoparticles, with 11 part-per-trillion detection limit (for uranium) and over million fold selectivity (over other radionuclides and metal ions tested). Practical application of the biosensors for samples from the Environmental Remediation Sciences Program (ERSP) Field Research Center (FRC) at Oak Ridge has also been demonstrated.

Yi Lu

2008-03-01

358

Polymer filtration systems for dilute metal ion recovery  

SciTech Connect

Scientists at Los Alamos National Laboratory have developed a metal recovery system that meets the global treatment demands for all kinds of industrial and metal-processing streams. The Polymer Filtration (PF) System--a process that is easily operated and robust--offers metal-finishing businesses a convenient and inexpensive way to recover and recycle metal ions in-house, thus reducing materials costs, waste removal costs, and industrial liability. As a valuable economic and environmental asset, the PF System has been named a winner of a 1995 R and D 100 Award. These awards are presented annually by R and D Magazine to the one hundred most significant technical innovations of the year. The PF System is based on the use of water-soluble metal-binding polymers and on advanced ultrafiltration membranes. Customers for this technology will receive new soluble polymers, especially formulated for their waste stream, and the complete PF processing unit: a reaction reservoir, pumps, plumbing, controls, and the advanced ultrafiltration membranes, all in a skid mounted frame. Metal-bearing waste water is treated in the reaction reservoir, where the polymer binds with the metal ions under balanced acid/base conditions. The reservoir fluid is then pumped through the ultrafiltration system--a cartridge packed with ultrafiltration membranes shaped in hollow fibers. As the fluid travels inside the fiber, water and other small molecules--simple salts such as calcium and sodium, for example--pass through the porous membrane walls of the fibers and are discharged through the outlet as permeate. The polymer-bound metal, which is too large to pass through the pores, is both purified and concentrated inside the hollow fibers and is returned to the fluid reservoir for further waste water treatment.

Smith, B.F.; Robison, T.W.; Jarvinen, G.D.

1998-12-01

359

Low energy ion beam assisted growth of metal multilayers  

NASA Astrophysics Data System (ADS)

Vapor deposited metal multilayers have attracted a great deal of interest in recent years because they offer extraordinary strength, hardness, heat resistance, and unexpected new properties like high reflectivity and spin-dependent conductivity. The giant magnetoresistance effects discovered in Fe/Cr artificial superstructures in 1988 stimulated a large number of studies on the electronic transport properties of spintronic materials because of their important applications in highly sensitive magnetic sensors, nonvolatile random access memories, and the data storage industry in general. Magnetic multilayers allow exploitation of unique micromagnetic, magnetooptic, and magnetoelectronic phenomena that cannot be realized using conventional materials. For example, if ferromagnetic layers (such as CoFe) with a thicknesses of 5-7 nm are separated by a non-magnetic spacer (such as Cu or AlOx) of an appropriate thickness (1-3 nm), they can exhibit large changes in their electrical resistance when a magnetic field is applied. These changes are caused mainly by spin-dependent conduction electron scattering at magnetic multilayer interfaces. Many experimental and theoretical works have sought to promote a basic understanding of the effect of atomic structure in thin film multilayers upon spin dependent transport. It has been found that interfacial imperfections, such as interfacial roughness and interlayer mixing, dramatically reduce the properties exploited for spintronic applications. A combination of computer modeling and experiments has been used to discover more effective ways to control the interfacial structures of metal multilayers. Earlier atomic simulations had indicated that it is very important to control adatom energy during deposition in order to improve interface properties. Based on these ideas, this dissertation has investigated the effects of low energy ion assistance during metal multilayer deposition. Using molecular dynamics modeling, the effects of ion energy, ion species, ion fluence, and ion incidence angle has been investigated during low energy ion assisted vapor deposition of Cu/Co mutilayers. Key mechanisms of atomic reconstruction in the low energy regime have been identified and investigated in detail using a molecular statics method. By changing the ion energy or modifying the time lag between metal and ion deposition, these simulations identified three different approaches for controlling the atomic assembly of multilayer: (i) simultaneous, (ii) modulated energy and (iii) sequential ion assistance. Each has been shown capable of enabling significant interfacial structure control during the growth of metallic multilayers. A biased target ion beam deposition (BTIBD) system was designed and constructed to provide growth environments similar to those that resulted in the best simulated film structures. The BTIBD system has been successfully employed to deposit a variety of multilayers. Experimental investigations of low energy ion assisted growth of a representative spin valve (Ta/NiFe/Co/Cu/Co/FeMn/Cu) multilayer and a model Ta/Cu film indicate significantly improved interfacial structures when oblique, low energy, argon ion assistance was used. These results are fully consistent with the simulations and confirm that a BTIBD approach to multilayer deposition results in substantially improved films compared to those synthesized by traditional ion beam assisted deposition approaches where less effective control of atomic self assembly is possible.

Quan, Junjie

360

LDRD Final Report on Designed Ionophores for Liquid-Membrane Separation and Extraction of Metal Ions.  

National Technical Information Service (NTIS)

New materials and processes for metal-ion separation and extraction based on selective transport of ions across membranes have been developed. Using molecular simulations, porphyrin-based ionophores (molecular ion-carriers) were designed for selectivity i...

J. A. Shelnutt A. Martino J. E. Miller

2001-01-01

361

Nuclear structure and astrophysics with accelerated beams of radioactive ions: A new multidisciplinary research tool  

SciTech Connect

After a brief discussion of the techniques for producing accelerated radioactive ion beams (RIBs), several recent scientific applications are mentioned. Three general nuclear structure topics, which can be addressed using RIBs, are discussed in some detail: possible modifications of the nuclear shell structure near the particle drip lines; various possibilities for decoupling the proton and neutron mass distributions for weakly bound nuclei; and tests of fundamental nuclear symmetries for self-conjugate and nearly self-conjugate nuclei. The use of RIBs to study r- and rp-process nucleosynthesis also is discussed.

Garrett, J.D.

1995-12-31

362

Gamma-Ray Spectroscopy at TRIUMF-ISAC: the New Frontier of Radioactive Ion Beam Research  

SciTech Connect

High-resolution gamma-ray spectroscopy is essential to fully exploit the unique scientific opportunities at the next generation radioactive ion beam facilities such as the TRIUMF Isotope Separator and Accelerator (ISAC). At ISAC the 8{pi} spectrometer and its associated auxiliary detectors is optimize for {beta}-decay studies while TIGRESS an array of segmented clover HPGe detectors has been designed for studies with accelerated beams. This paper gives a brief overview of these facilities and also presents recent examples of the diverse experimental program carried out at the 8{pi} spectrometer.

Ball, G. C.; Bandyopadhyay, D.; Bricault, P.; Chan, S.; Churchman, R.; Coombes, H.; Dombsky, M.; Garnsworthy, A.; Hackman, G.; Lassen, J.; Morton, A. C.; Pearson, C. J.; Triambak, S.; Williams, S. J. [TRIUMF 4004 Wesbrook, Vancouver BC, V6T 2A3 (Canada); Andreoiu, C.; Cross, D. [Department of Chemistry, Simon Fraser University, Burnaby, BC, V5A IS6 (Canada); Austin, R. A. E.; Colosimo, S.; Kanungo, R. [Department of Astronomy and Physics, St. Mary's University, Halifax, NS, B3H 3C3 (Canada); Becker, J. A. [Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States)] (and others)

2009-03-31

363

Nova Nucleosynthesis Calculations: Robust Uncertainties, Sensitivities, and Radioactive Ion Beam Measurements  

NASA Astrophysics Data System (ADS)

We examine the quantitative impact of nuclear physics uncertainties on predictions of nova models via Monte Carlo simulations wherein, for the first time, the uncertainties of all relevant nuclear reactions are considered simultaneously. We determine uncertainties in predictions of isotope synthesis - including radioisotopes which may be observable tracers of novae - resulting from uncertainties in the input nuclear physics. We also detail the reaction rate sensitivity of radioisotope production, and discuss reactions which need further study. Finally, we examine the influence on nova nucleosynthesis of two new reaction rates - 17F(p,?)18Ne and 14O(?,2p)16O - that were studied in recent ORNL measurements with radioactive ion beams.

Smith, Michael S.; Hix, W. R.; Parete-Koon, S.; Dessieux, L.; Guidry, M. W.; Bardayan, D. W.; Starrfield, S.; Smith, D. L.; Mezzacappa, A.

2002-11-01

364

Study of Collectivity in n-rich A=80 Nuclei using Radioactive Ion Beams  

NASA Astrophysics Data System (ADS)

We report on recent experiments performed at the HRIBF of Oak Ridge National Laboratory (ORNL) aimed to study neutron-rich nuclei in the A 80 mass region. First time use of Radioactive Ion Beams (RIBs) (78,80)Ge complemented with stable beam information allowed a systematic study of B(E2)-values that characterize the n-rich even-even Ge and Se isotopes. A comparison of the experimental results with IBA2 calculations will be presented. *Supported by US-DOE under the contract DE-AC05-00AOR22725.

Padilla, E.; Galindo-Uribarri, A.; Baktash, C.; Fuentes, B.; Gross, C.; Mueller, P.; Radford, D. C.; Stracener, D.; Yu, C.-H.; Bijker, R.; Castanos, O.; Batchelder, J.; Hartley, D. J.

2002-04-01

365

Review of work related to ion sources and targets for radioactive beams at Argonne  

SciTech Connect

A group including many ANL Physics Division staff and ATLAS outside users has discussed the possibilities for research with radioactive ion beams and prepared a working paper entitled {open_quotes}Concept for an Advanced Exotic Beam Facility Based on ATLAS.{close_quotes} Several subgroups have been working on issues related to ion sources and targets which could be used in the production and ionization of radionuclides with high power primary beams. Present activities include: (a) setting up an ion source test stand to measure emittances and energy spreads of ISOL-type ion sources, (b) experiments to evaluate methods of containing liquid uranium for production targets, (c) experimental evaluation of geometries for the generation of secondary neutron beams for production of radionuclides, (d) setting up an ISOL-type ion source at a neutron generator facility to measure fission fragment release times and efficiencies, and (e) computer simulations of an electron-beam charge-state amplifier to increase the charge states of 1{sup +} secondary beams to 2,3 or 4{sup +}. The present status of these projects and future plans are reported below.

Nolen, J.A.

1995-12-01

366

Microbial metal-ion reduction and Mars: extraterrestrial expectations?  

PubMed

Dissimilatory metal-ion-reducing bacteria (DMRB) can couple the reduction of a variety of different metal ions to cellular respiration and growth. The excitement of this metabolic group lies not only in the elucidation of a new type of metabolism, but also in the potential use of these abilities for the removal of toxic organics, and in their ability to reduce (and thus, detoxify) other toxic metals, such as U(VI) and Cr(VI). This review focuses on recent advances in the study of DMRB, including the use of external electron shuttles to enhance rates of metal reduction; genome sequencing and consequent genomic and proteomic analyses; new imaging approaches for high resolution analysis of both cells and chemical components; the demonstration of fractionation of stable isotopes of iron during iron reduction; and the elucidation of the types and patterns of secondary mineral formation during metal reduction. One of the secondary minerals is magnetite, the subject of intense controversy regarding the possibility of evidence for life from the Martian meteorite ALH84001. This review thus ends with a short consideration of the evidence for magnetic 'proof' of the existence of past life on Mars. PMID:12057684

Nealson, Kenneth H; Cox, B Lea

2002-06-01

367

Metal fluoride coatings prepared by ion-assisted deposition  

NASA Astrophysics Data System (ADS)

ArF lithography technology requires minimization of optical losses due to scattering and absorption. Consequently, it is necessary to optimize the coating process of metal fluorides. The properties of metal fluoride thin films are mainly affected by the deposition methods, their parameters (temperature and deposition rate) and the vacuum conditions. A substrate temperature of more than 300°C is a condition for high density and low water content of metal fluorides. Therefore, a substrate temperature of 150°C results in inhomogeneous films with high water content. Until now, the best results were achieved by boat evaporation. This paper will demonstrate that most of the common metal fluorides like MgF2, AlF3, and even LaF3 can be deposited by electron beam evaporation. In comparison to other deposition methods, the prepared thin films have the lowest absorption in the VUV spectral range. Furthermore, metal fluoride thin films were prepared by ion assistance. It will be demonstrated, that they have less water content, high packing density, and low absorption in the VUV spectral range. In this study, single layers of LaF3 and AlF3 and antireflection coatings were prepared by electron beam evaporation with and without ion-assistance. The mechanical, structural, and optical properties were examined and discussed.

Bischoff, Martin; Sode, Maik; Gäbler, Dieter; Bernitzki, Helmut; Zaczek, Christoph; Kaiser, Norbert; Tünnermann, Andreas

2008-09-01

368

Functional Characterization and Metal Ion Specificity of the Metal-Citrate Complex Transporter from Streptomyces coelicolor  

Microsoft Academic Search

Secondary transporters of citrate in complex with metal ions belong to the bacterial CitMHS family, about which little is known. The transport of metal-citrate complexes in Streptomyces coelicolor has been investigated. The best cofactor for citrate uptake in Streptomyces coelicolor is Fe3, but uptake was also noted for Ca2 ,P b2, Ba2, and Mn2. Uptake was not observed with the

Joshua J. Lensbouer; Ami Patel; Joseph P. Sirianni; Robert P. Doyle

2008-01-01

369

Metal dicarbides as intermediate species in thermal ion formation mechanisms  

NASA Astrophysics Data System (ADS)

Lanthanide elements (lanthanum to lutetium) and actinide elements (uranium and plutonium) adsorbed onto resin beads and mounted on rhenium filaments were studied as thermal ionization sources. Temperatures at which these ion sources gave maximum intensities were measured for each of these elements. The temperature trends correlate with the dissociation energies of the corresponding metal dicarbide compounds. The metal dicarbide functions as a carrier to take the lanthanide and actinide elements to higher temperatures than would be attainable otherwise. This results in release of the atomic species at a higher temperature where ionization probability is significantly increased.

Watrous, Matthew G.; Delmore, James E.

2009-09-01

370

The corrosion protection of metals by ion vapor deposited aluminum  

SciTech Connect

A study of the corrosion protection of substrate metals by ion vapor deposited aluminum (IVD Al) coats has been carried out. Corrosion protection by both anodized and unanodized IVD Al coats has been investigated. Base metals included in the study were 2219-T87 Al, 7075-T6 Al, Titanium-6 Al-4 Vanadium (Ti-6Al-4V), 4130 steel, D6AC steel, and 4340 steel. Results reveal that the anodized IVD Al coats provide excellent corrosion protection, but good protection is also achieved by IVD Al coats that have not been anodized.

Danford, M.D.

1993-10-01

371

CHARACTERIZATION OF METAL BINDING SITES IN FULVIC ACIDS BY LANTHANIDE ION PROBE SPECTROSCOPY  

EPA Science Inventory

Naturally occurring humic substances are known to be potentially strong binders of metals in the environment. ensitive spectroscopic technique, based on the unique luminescent properties of the tripositive lanthanide metal ions, has been developed to Selectively probe metal bindi...

372

NOVEL APPROACH TO METAL-HUMIC COMPLEXATION STUDIES BY LANTHANID ION PROBE SPECTROSCOPY  

EPA Science Inventory

Naturally occurring humic substances are known to be potentially strong binders of metals in the environment. ensitive spectroscopic technique, based on the unique luminescence properties of the tripositive lanthanide metal ions, has been developed to selectively probe metal bind...

373

Charge state breeding of radioactive ions with an electron cyclotron resonance ion source at TRIUMF  

SciTech Connect

Efficient primary ion sources at ISOL facilities normally produce singly charged ions. This limits the usable mass range for postacceleration due to the A/Q acceptance of the accelerator. At the ISAC facility at TRIUMF an A/Q below 7 is desired to avoid further stripping. Thus, charge state breeding is necessary if higher masses are to be accelerated. A 14 GHz ECRIS 'PHOENIX' booster has been chosen as a breeder. In order to investigate and optimize its performance under ISAC conditions it has been set up at a test bench equipped with a standard ISAC target-ion-source to produce singly charged ions. A series of measurements has been performed with the noble gases Ar, Kr, and Xe. Efficiencies of more than 6% in the maximum of the charge state distribution after mass separation have been obtained and the emittance of the extracted beam and breeding times have been measured. This article gives a status report on the ongoing measurements.

Ames, F.; Baartman, R.; Bricault, P.; Jayamanna, K.; McDonald, M.; Olivo, M.; Schmor, P.; Yuan, D.H.L.; Lamy, T. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3 (Canada); LPSC, UJF-IN2P3-CNRS, 53 Avenue des Martyrs, 38026 Grenoble (France)

2006-03-15

374

Production of radioactive Ag ion beams with a chemically selective laser ion source  

NASA Astrophysics Data System (ADS)

We have developed a chemically selective laser ion source at the CERN-ISOLDE facility in order to study neutron-rich Ag nuclides. A pulsed laser system with high repetition rate has been used based on high-power copper-vapour pump lasers and dye lasers. With this source significant reductions of the isobaric background has been achieved.

Jading, Y.; Catherall, R.; Jokinen, A.; Jonsson, O. C.; Kugler, E.; Lettry, J.; Ravn, H. L.; Tengblad, O.; Kautzsch, T.; Klöckl, I.; Kratz, K.-L.; Scheerer, F.; Fedoseyev, V. N.; Mishin, V. I.; van Duppen, P.; Wöhr, A.; Walters, W. B.

1996-04-01

375

Complementary Metal Ion Specificity of the Metal-Citrate Transporters CitM and CitH of Bacillus subtilis  

Microsoft Academic Search

Citrate uptake in Bacillus subtilis is stimulated by a wide range of divalent metal ions. The metal ions were separated into two groups based on the expression pattern of the uptake system. The two groups correlated with the metal ion specificity of two homologous B. subtilis secondary citrate transporters, CitM and CitH, upon expression in Escherichia coli. CitM transported citrate

Wil N. Konings; Jessica B. Warner; Bastiaan P. Krom; Juke S. Lolkema

2000-01-01

376

Investigation of the metal species in seawater by sorption of the metal ion on complexing resins with different sorbing properties  

Microsoft Academic Search

The distribution of some metal ions in seawater samples among different species was investigated by the resin titration (RT) procedure, based on the separation of the metal ion on resins with different sorbing properties. Two complexing resins were used for the titration of four metal ions (Cu(II), Cd(II), Ni(II) and Mn(II)): Amberlite CG 50 and Chelex 100. The first one

Maria Pesavento; Raffaela Biesuz; Cinzia Gnecco; Emanuele Magi

2001-01-01

377

A molecular metal with ion-conducting channels  

Microsoft Academic Search

Metallic behaviour is well known in charge-transfer complexes that contain stacks of planar, partially oxidized (or reduced) pi-conjugated molecules. Electronic conduction occurs in the partially occupied, delocalized pi bands formed by intermolecular orbital overlap, and some of these materials exhibit superconductivity,. Counter-ions, present to achieve charge neutrality, usually play a passive role, although in some cases they couple to the

Takayoshi Nakamura; Tomoyuki Akutagawa; Kazumasa Honda; Allan E. Underhill; A. Treeve Coomber; Richard H. Friend

1998-01-01

378

Precious metal catalysts with oxygen-ion conducting support  

SciTech Connect

A three-way supported catalyst is described for treatment of combustion gas emissions from mobile or stationary sources, comprising: an oxygen-ion conducting support material having surface area at least about 20 m[sup 2]/gm, and two active metals selected from the group consisting of (1) platinum and rhodium and (2) palladium and rhodium dispersed on the support material in overall amount of about 0.01-2.2 wt. % of the catalyst.

Ganguli, P.S.; Sundaresan, S.

1993-08-03

379

A Novel Family of Ubiquitous Heavy Metal Ion Transport Proteins  

Microsoft Academic Search

.   We describe a novel diverse family of metal ion transporter (CDF) proteins (the cation diffusion facilitator (CDF) family)\\u000a with members occurring in both prokaryotes and eukaryotes. Thirteen sequenced protein members of the CDF family have been\\u000a identified, several of which have been shown to transport cobalt, cadmium and\\/or zinc. All members of the CDF family possess\\u000a six putative transmembrane

I. T. Paulsen

1997-01-01

380

Equilibrium sorption isotherm for metal ions on tree fern  

Microsoft Academic Search

A new sorbent system for removing heavy metal ions, such as Zn(II), Cu(II) and Pb(II), from aqueous solutions has been investigated. This new sorbent is tree fern, an agriculture product. Variables of the system include solution temperature and sorbent particle size. The experimental results were fitted to the Langmuir, Freundlich and Redlich–Peterson isotherms to obtain the characteristic parameters of each

Y. S. Ho; C. T. Huang; H. W. Huang

2002-01-01

381

Thermal analysis of protein–metallic ion systems  

Microsoft Academic Search

Advanced thermal analysis methods, such as temperature modulated DSC (differential scanning calorimetry) and quasi-isothermal\\u000a TMDSC were used to analyze the protein–metallic ion interactions in silk fibroin proteins. The precise heat capacities were\\u000a measured and theoretically predicted in this study. To remove bound water and simplify the system, a thermal cycling treatment\\u000a through both standard DSC and TMDSC was used to

Xiao Hu; David Kaplan; Peggy Cebe

2009-01-01

382

Modified SBA15 mesoporous silica for heavy metal ions remediation  

Microsoft Academic Search

N-Propylsalicylaldimino-functionalized SBA-15 mesoporous silica was prepared, characterized and used as an adsorbent for heavy metal ions. The organic–inorganic hybrid material was obtained using successive grafting procedures of SBA-15 silica with 3-aminopropyl-triethoxysilane and salicylaldehyde, respectively. For comparison an amorphous silica gel was functionalized using the same procedure. The structure and physicochemical properties of the materials were characterized by means of elemental

Mihaela Mureseanu; Aurora Reiss; Ioan Stefanescu; Elena David; Viorica Parvulescu; Gilbert Renard; Vasile Hulea

2008-01-01

383

Removal of toxic metal ions with magnetic hydrogels  

Microsoft Academic Search

Hydrogels, based on 2-acrylamido-2-methyl-1-propansulfonic acid (AMPS) were synthesized via photopolymerization technique and used for the preparation of magnetic responsive composite hydrogels. These composite hydrogels with magnetic properties were further utilized for the removal of toxic metal ions such as Cd(II), Co(II), Fe(II), Pb(II), Ni(II), Cu(II) and Cr(III) from aqueous environments. It was revealed that hydrogel networks with magnetic properties can

Ozgur Ozay; Sema Ekici; Yakup Baran; Nahit Aktas; Nurettin Sahiner

2009-01-01

384

ION-ALKALI-METAL BEHAVI OR FOR LITHI UMf  

Microsoft Academic Search

It is shown that the non-alkali-metal behavior of the electrical resisti- vity of lithium stems from the unusually large values of the screened electron-ion pseudopotential matrix elements. The standard free-electron resistivity calculation is significantly in error for lithium at low temperatures, not only for the magnitude of the resistivity, but also for its temperature dependence, the phonon-drag contri- bution, and

M. Danino; M. Kaveh; N. Wiser

385

The application of metal cutting technologies in tasks performed in radioactive environments  

SciTech Connect

The design and use of equipment to perform work in radioactive environments is uniquely challenging. Some tasks require that the equipment be operated by a person wearing a plastic suit or full face respirator and donning several pairs of rubber gloves. Other applications may require that the equipment be remotely controlled. Other important, design considerations include material compatibility, mixed waste issues, tolerance to ionizing radiation, size constraints and weight capacities. As always, there is the ``We need it ASAP`` design criteria. This paper describes four applications where different types of metal cutting technologies were used to successfully perform tasks in radioactive environments. The technologies include a plasma cutting torch, a grinder with an abrasive disk, a hydraulic shear, and a high pressure abrasive water jet cutter.

Fogle, R.F.; Younkins, R.M.

1997-05-01

386

The Holifield Radioactive Ion Beams Facility (HRIBF) -- getting ready to do experiments  

SciTech Connect

The conversion of the HHIRF facility to a Radioactive Ion Beam facility started in 1994. In this ISOL type facility the Cyclotron has been re-fitted as a driver providing high intensity proton beams which react with the target from which the radioactive products are extracted and then accelerated in the Tandem Electrostatic Accelerator to the desired energy for nuclear science studies. Facilities for nuclear physics experiments are at different stages of development: A Recoil Mass Spectrometer (RMS) with a complement of detectors at the focal plane and around the target is used primarily for nuclear structure studies. A large recoil separator combining velocity and momentum selection, with its complement of focal plane detectors, will be dedicated to measurements relevant to nuclear astrophysics. The Enge Split Pole spectrograph is being re-fitted for operation in a gas filled mode, making it a more versatile tool for nuclear reaction studies. With the new experimental equipment being commissioned and the prospects of running experiments with low intensity radioactive beams a significant effort to develop equipment for beam diagnostics is underway. Some of the efforts and results in developing beam diagnostic tools will be described.

Shapira, D.; Lewis, T.A.

1998-02-26

387

The HyBall Charged Particle Detector System for Radioactive Ion Beams  

NASA Astrophysics Data System (ADS)

We describe the Hybrid-4pi (HyBall) compact array of charged-particle detectors being used at ORNL with Radioactive Ion Beams (RIB) for studies in Nuclear Structure and Nuclear Reactions. It consists of two parts: a) up to 95-element CsI (T1)-crystals coupled to large area photodiodes and b) a forward array of double sided silicon strip detectors. The versatile array allows its main components to be used separately and to be reconfigured. The HyBall array is housed in an aluminum target chamber with a forward funnel that accommodates the microstrip-Si-detectors. When used with the CLARION array of clover Ge detectors, the geometry of this chamber minimizes the exposure of the Ge- and CsI-detectors to the gamma-rays and positrons resulting from the decay of the scattered radioactive ions. We will show examples of the HyBall performance from recent RIB experiments. *Supported by US-DOE under the contract DE-AC05-00AOR22725.

Larochelle, Y.; Galindo-Uribarri, A.; Baktash, C.; Bennet, W.; Gross, C. J.; Johnson, J.; Mas, J.; McConnell, J.; Radford, D. C.; Padilla, E.; Pascual, S.

2002-04-01

388

The effect of ion implanting on hydrogen entry into metals  

SciTech Connect

The effectiveness of platinum ion implanting in mitigating hydrogen entry into 4340 steel is measured and quantified. Data are presented to compare the extent of hydrogen absorption by the substrate during electrolytic hydrogen charging of platinum ion-implanted and unimplanted 4340 steel substrates. Several implanting conditions were used in processing the samples, and the surface-limited mass-transfer coefficient was calculated for each case and used to quantify the effectiveness of each treatment in reducing hydrogen absorption. It is shown that the underlying mechanism for reducing hydrogen absorption by platinum ion-implanted substrates is the catalytic effect of platinum that favors hydrogen evolution at the steel`s surface over hydrogen absorption by the metal. Although scattering experiments with low energy helium ions suggest that the platinum content in the first monolayer of platinum-implanted steels is small, the ability of Pt to catalyze the hydrogen evolution reaction is still strong enough to significantly reduce the quantity of hydrogen that enters the metal.

Chou, S.C.; Makhlouf, M.M. [Worcester Polytechnic Inst., MA (United States). Dept. of Mechanical Engineering

1999-06-01

389

Determination of metal ions by ion chromatography with precolumn electrochemical preconcentration.  

PubMed

The determination of heavy metals in concentrations less than 10(-6) mol/L by ion chromatography with conductivity detection requires a preconcentration step. Therefore, a special electrochemical equipment and method was developed for the on-line preconcentration of the divalent metals Ni, Co, Zn and Cd and their subsequent ion chromatographic determination. The loop of the injection valve of an ion chromatograph was replaced by an electrochemical flow-through-cell with a gold working electrode, a platinum auxiliary electrode and a silver/silver sulphate reference electrode. The preconcentration step consists of the deposition of the reduced metals on the electrode surface during a continuous pumping of the sample solution through the cell. After switching of the mobile phase through the cell, the analytes are injected after their reoxidation directly into the mobile phase. A new preconcentration step is simultaneously possible during the actual chromatographic run. An effective separation of the analytes from the matrix is also possible with the proposed system. A maximum of metal ion accumulation was obtained after 120 min in the galvanostatic mode on a gold tube electrode. The detection limits for Co(II), Ni(II), Zn(II) and Cd(II) were improved by a factor of 7.7, 10.4, 11.2, 14.0, respectively, and were in the 0.1 micromol/L concentration range with a RSD of 2-6%. The accumulation of metal ions was disturbed in the presence of Cr(III). PMID:15067479

Hissner, F; Mattusch, J; Werner, G

1996-03-01

390

Reexamination of the ORAC assay: effect of metal ions.  

PubMed

The oxygen radical absorbance capacity (ORAC) assay method has been employed extensively in the field of antioxidant and oxidative stress. It uses fluorescein as probe for oxidation by peroxyl radical. Hundreds of reports have been published on the use of this method to determine antioxidant capacity in food and biological samples. The question is whether the results of all these reports are influenced by antioxidant autoxidation, which occurs during the ORAC test. Indeed, the presence of metal ions in the studied matrix will influence antioxidant stability, thereby leading to the underestimation of their antioxidant properties. Ethylenediaminetetraacetic acid hydrate (EDTA) can be used as a metal complexation agent. This paper examines the effect of the addition of EDTA on the ORAC values of pure compounds (quercetin, ascorbic, and dehydroascorbic acid) and five food juices (kiwi, orange, tomato, red grape, and apple). Metal complexation by EDTA (80 ?M) clearly increased the ORAC values, given that the antioxidant was protected against rapid autoxidation incited by trace metal ions within samples and then by free radicals. Our finding also undoubtedly demonstrated that the number of literature values is potentially underestimated. PMID:21512895

Nkhili, E; Brat, P

2011-04-06

391

SOLVENT EXTRACTION OF METAL IONS AND SEPARATION OF NICKEL(II) FROM OTHER METAL IONS BY ORGANOPHOSPHORUS ACIDS  

Microsoft Academic Search

Such physicochemical properties of bis(2-ethylhexyl)phosphinic acid, 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester and bis(2-ethylhexyl)phosphoric acid as the solubilities and the dissociation constants in water, the dimerization constants in organic solvent and distribution constants in organic solvent-water were examined by a potentiometric two-phase titration. The solvent extraction of seven kinds of transition metal ions and magnesium(II) from aqueous sulfate media was studied with

Yao Binghua; Yukio Nagaosa; Masatada Satake; Akihiko Nomura; Kiyoshi Horita

1996-01-01

392

Infrared Spectroscopy of Hydrated Doubly-Charged Metal Ions Produced by Electrospray Ionization  

Microsoft Academic Search

Until now, a large number of studies on the microscopic solvation effect of metal ion have been carried out. However, a very small number of spectroscopic studies on the doubly-charged metal ions are reported compared with that on the singly-charged ion. Since doubly-charged metal ions are highly energetic, electron- or proton- transfer reactions with solvent molecules should compete with the

Haruki Ishikawa; Toru Eguchi; Akimasa Fujihara; Yuji Yamada; Kiyokazu Fuke

2009-01-01

393

Surface modified, collapsible controlled pore glass materials for sequestration and immobilization of trivalent metal ions.  

SciTech Connect

We report a one-pot method for sequestration, containment, and immobilization of lanthanide (Ln) ions from dilute aqueous waste streams. The approach is based on the use of collapsible, surface modified controlled pore glass (CPG) nanomaterials. We present several approaches for a single-step chemical modification of 3-propylaminated CPGs that yield highly efficient Ln-extracting materials with distribution coefficients exceeding 10000 mL/g. The resulting Ln complexes were studied using X-ray absorption, magnetic resonance, and time-resolved luminescence spectroscopies. One of these CPG materials involving an imidodi(methanediphosphate) moiety demonstrated high extraction efficacy, significant ionic radius sensitivity, and exceptional tolerance to masking agents, which is conducive to its use for removal of traces of radionuclide ions from aqueous TALSPEAK raffinate (trivalent actinide-lanthanide separation by phosphorus reagent extraction from aqueous complexes process used in processing of spent nuclear fuel). The glass loaded with the extracted metal ions can be calcined and sintered at 1100 C, yielding fused material that buries Ln ions in the vitreous matrix. This processing temperature is significantly lower than 1700 C that is required for direct vitrification of lanthanide oxides in high-silica glass. X-ray absorption spectroscopy and acid leaching tests indicate that the immobilized ions are isolated and dispersed in the fused glass matrix. Thus, the method integrates Ln ions into the glass network. The resulting glass can be used for temporary storage or as the source of silica for production of borosilicate waste forms that are used for long-term disposal of high level radioactive waste.

Shkrob, I.; Tisch, A.; Marin, T.; Muntean, J.; Kaminski, M.; Kropf, A. (Chemical Sciences and Engineering Division); (Benedictine Univ.)

2011-04-20

394

Fluorescence Spectroscopy of Polymer Systems Doped with Rare-Earth Metal Ions and Their Complexes  

Microsoft Academic Search

There has been an increased attention to explore the possibility of using polymer materials with rare-earth (RE) metal ions and their complexes as potential optical materials due to their capability of exhibiting novel and unusual properties. The fluorescence characteristics of polymer systems doped with RE metal ions and\\/or their complexes were analyzed and the effects of the doping metal ion\\/metal

K. S. V. Krishna Rao; Hong-Guo Liu; Yong-Ill Lee

2010-01-01

395

METAL-ION ABSORPTION IN CONDUCTIVELY EVAPORATING CLOUDS  

SciTech Connect

We present computations of the ionization structure and metal-absorption properties of thermally conductive interface layers that surround evaporating warm spherical clouds embedded in a hot medium. We rely on the analytical steady-state formalism of Dalton and Balbus to calculate the temperature profile in the evaporating gas, and we explicitly solve the time-dependent ionization equations for H, He, C, N, O, Si, and S in the conductive interface. We include photoionization by an external field. We estimate how departures from equilibrium ionization affect the resonance-line cooling efficiencies in the evaporating gas, and determine the conditions for which radiative losses may be neglected in the solution for the evaporation dynamics and temperature profile. Our results indicate that nonequilibrium cooling significantly increases the value of the saturation parameter {sigma}{sub 0} at which radiative losses begin to affect the flow dynamics. As applications, we calculate the ion fractions and projected column densities arising in the evaporating layers surrounding dwarf-galaxy-scale objects that are also photoionized by metagalactic radiation. We compare our results to the UV metal-absorption column densities observed in local highly ionized metal absorbers, located in the Galactic corona or intergalactic medium. Conductive interfaces significantly enhance the formation of high ions such as C{sup 3+}, N{sup 4+}, and O{sup 5+} relative to purely photoionized clouds, especially for clouds embedded in a high-pressure corona. However, the enhanced columns are still too low to account for the O VI columns ({approx}10{sup 14} cm{sup -2}) observed in the local high-velocity metal-ion absorbers. We find that column densities larger than {approx}10{sup 13} cm{sup -2} cannot be produced in evaporating clouds. Our results do support the conclusion of Savage and Lehner that absorption due to evaporating O VI likely occurs in the local interstellar medium, with characteristic columns of {approx}10{sup 13} cm{sup -2}.

Gnat, Orly [Theoretical Astrophysics, California Institute of Technology, MC 350-17, Pasadena, CA 91125 (United States); Sternberg, Amiel [School of Physics and Astronomy and the Wise Observatory, Beverly and Raymond Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978 (Israel); McKee, Christopher F., E-mail: orlyg@tapir.caltech.ed [Departments of Physics and Astronomy, University of California, Berkeley, Campbell Hall, Berkeley, CA 94720-7304 (United States)

2010-08-01

396

Metal-ion Absorption in Conductively Evaporating Clouds  

NASA Astrophysics Data System (ADS)

We present computations of the ionization structure and metal-absorption properties of thermally conductive interface layers that surround evaporating warm spherical clouds embedded in a hot medium. We rely on the analytical steady-state formalism of Dalton and Balbus to calculate the temperature profile in the evaporating gas, and we explicitly solve the time-dependent ionization equations for H, He, C, N, O, Si, and S in the conductive interface. We include photoionization by an external field. We estimate how departures from equilibrium ionization affect the resonance-line cooling efficiencies in the evaporating gas, and determine the conditions for which radiative losses may be neglected in the solution for the evaporation dynamics and temperature profile. Our results indicate that nonequilibrium cooling significantly increases the value of the saturation parameter ?0 at which radiative losses begin to affect the flow dynamics. As applications, we calculate the ion fractions and projected column densities arising in the evaporating layers surrounding dwarf-galaxy-scale objects that are also photoionized by metagalactic radiation. We compare our results to the UV metal-absorption column densities observed in local highly ionized metal absorbers, located in the Galactic corona or intergalactic medium. Conductive interfaces significantly enhance the formation of high ions such as C3+, N4+, and O5+ relative to purely photoionized clouds, especially for clouds embedded in a high-pressure corona. However, the enhanced columns are still too low to account for the O VI columns (~1014 cm-2) observed in the local high-velocity metal-ion absorbers. We find that column densities larger than ~1013 cm-2 cannot be produced in evaporating clouds. Our results do support the conclusion of Savage and Lehner that absorption due to evaporating O VI likely occurs in the local interstellar medium, with characteristic columns of ~1013 cm-2.

Gnat, Orly; Sternberg, Amiel; McKee, Christopher F.

2010-08-01

397

Radiation damage from single heavy ion impacts on metal surfaces  

SciTech Connect

The effects of single ion impacts on the surfaces of films of Au, Ag, In and Pb have been studied using in-situ transmission electron microscopy. On all of these materials, individual ion impacts produce surface craters, in some cases, with associated expelled material. The cratering efficiency scales with the density of the irradiated metal. For very thin Au foils ({approx} 20--50 nm), in some cases individual ions are seen to punch small holes completely through the foil. Continued irradiation results in a thickening of the foil. The process giving rise to crater and hole formation and other changes observed in the thin foils has been found to be due to pulsed localized flow--i.e. melting and flow due to the thermal spikes arising from individual ion impacts. Experiments carried out on thin films of silver sandwiched between SiO{sub 2} layers have indicated that pulsed localized flow also occurs in this system and contributes to the formation of Ag nanoclusters in SiO{sub 2}--a system of interest for its non-linear optical properties. Calculation indicates that, when ion-induced, collision cascades occur near surfaces (within {approx} 5 nm) with energy densities sufficient to cause melting, craters are formed. Crater formation occurs as a result of the explosive outflow of material from the hot molten core of the cascade. Processes occurring in the sandwiched layer are less well understood.

Donnelly, S.E. [Univ. of Salford, Manchester (United Kingdom); Birtcher, R.C. [Argonne National Lab., IL (United States). Materials Science Div.

1998-06-01

398

Ion Sputtering from Organic Liquid Matrices Bombarded by KEV Metal Ions.  

NASA Astrophysics Data System (ADS)

Ion sputtering from organic liquid matrices bombarded by 7-66 keV metal ions has been systematically studied as a function of the properties of the primary ions (species, energy etc.) and of the chemical environment on the target's surface. Yields of deprotonated mononucleotides (dAMP or dGMP) from a glycerol matrix, doped with the surfactant hexadecylpyridinium acetate (HDPA), as a function of stopping power (dE/dX) can be explained by models, such as the cylindrical thermal spike model with Y = k(dE/dX - S_0)^2 (S _0 = threshold stopping power), that predict particle ejection essentially from the surface. Moreover, yields of deprotonated dAMP or dGMP generated by bombardment with polyatomic ions (Bi_3^{+2 }, Bi_2^+, Au _2^+, Au _3^+) exhibit a nonlinear enhancement over those generated by bombardment with monoatomic ions (Au^+, Bi^+). Nonlinear in this case means that the number of ions ejected by a given number of atoms colliding with a liquid matrix at essentially the same point in space and time, as is the case when the atoms are clustered into a single ion, is much greater than that produced by an equal number of atoms impacting individually on the same target at different positions and times. This enhancement can also be explained by, for example, the cylindrical thermal spike model.

Yen, Ten-Yang

399

An overview on TRIUMF's developments on ion source for radioactive beams (invited)  

SciTech Connect

The ISAC facility at TRIUMF utilizes up to 100 {mu}A from the 500 MeV H{sup -} cyclotron to produce the radioactive ion beam (RIB) using the isotopic separation on line method. The ISAC-I facility comprised the RIB production target stations, the mass separator, and the beam delivery to low energy area and to a room temperature linear accelerator composed of a four-rod radio frequency quadrupole and an interdigital H-type structure drift tube LINAC. ISAC-I linear accelerator can provide beam from A=3 to 30 amu with an energy range from 0.15 to 1.5 A MeV. Since the beginning of operations target development program has been to increase proton beam currents on targets. Now we routinely operate our target at 50-85 {mu}A and recently we have operated our target at 100 {mu}A. Other developments are in place to add other ion sources, laser, force electron beam induced are discharge and electron cyclotron resonance ion source to the actual surface ion source. The last two five year plans were mainly devoted to the construction of a heavy ion superconducting LINAC (ISAC-II) that will upgrade the mass and the energy range from 30 to 150 and from 1.5 to 6.5 A MeV, respectively. The intermediate stage E{<=}4.2 A MeV is already completed and commissioned; three experiments using {sup 11}Li, {sup 9}Li, and {sup 29}Na have been completed this summer.

Bricault, Pierre; Ames, Friedhelm; Achtzehn, Tobias; Dombsky, Marik; Labrecque, Francis; Lassen, Jens; Lavoie, Jean-Phillipe; Lecesne, Nathalie [TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, V6T 2A3 (Canada); GANIL, Boulevard Henri Becquerel, B.P. 55027, 14076 Caen Cedex 05 (France)

2008-02-15

400

Correlation between the limiting pH of metal ion solubility and total metal concentration  

SciTech Connect

As an alternative to species distribution diagrams (pM vs pH curves in aqueous solution) drawn for a fixed total metal concentration, this work has developed simple linear models for correlating the limiting pH of metal ion solubility -- in equilibrium with the least soluble amorphous metal hydroxide solid phase -- to the total metal concentration. Thus adsorptive metal removal processes in complex systems can be better designed once the limiting pH of heavy metal solubility (i.e., pH{sup *}) in such a complex environment can be envisaged by simple linear equations. pH{sup *} vs pM{sub t} (M{sub t} = total metal concentration that can exist in aqueous solution in equilibrium with M(OH){sub 2(s)}) linear curves for uranyl-hydroxide, uranyl-carbonate-hydroxide, and mercuric-chloride-hydroxide simple and mixed-ligand systems and cupric-carbonate-hydroxide complexes in equilibrium with mixed hydroxide solid phases may enable the experimental chemist to distinguish true adsorption (e.g., onto hydrous oxide sorbents) from bulk precipitation removal of the metal and to interpret some anomalous metal fixation data -- usually attributed to pure adsorption in the literature -- with precipitation if the pM{sub t} at the studied pH is lower than that tolerated by pH{sup *} vs pM{sub t} curves. This easily predictable pH{sup *} corresponding to a given pM{sub t} may aid the design of desorptive mobilization experiments for certain metals as well as their adsorptive removal with the purpose of simulating metal adsorption and desorption cycles in real complex environments with changing groundwater pH.

Apak, R.; Hizal, J.; Ustaer, C. [Istanbul Univ. (Turkey)

1999-03-15

401

Correlation between the Limiting pH of Metal Ion Solubility and Total Metal Concentration.  

PubMed

As an alternative to species distribution diagrams (pM vs pH curves in aqueous solution) drawn for a fixed total metal concentration, this work has developed simple linear models for correlating the limiting pH of metal ion solubility-in equilibrium with the least soluble amorphous metal hydroxide solid phase-to the total metal concentration. Thus adsorptive metal removal processes in complex systems can be better designed once the limiting pH of heavy metal solubility (i.e., pH*) in such a complex environment can be envisaged by simple linear equations. pH* vs pMt (Mt = total metal concentration that can exist in aqueous solution in equilibrium with M(OH)2(s)) linear curves for uranyl-hydroxide, uranyl-carbonate-hydroxide, and mercuric-chloride-hydroxide simple and mixed-ligand systems and cupric-carbonate-hydroxide complexes in equilibrium with mixed hydroxide solid phases may enable the experimental chemist to distinguish true adsorption (e.g., onto hydrous oxide sorbents) from bulk precipitation removal of the metal and to interpret some anomalous metal fixation data-usually attributed to pure adsorption in the literature-with precipitation if the pMt at the studied pH is lower than that tolerated by pH* vs pMt curves. This easily predictable pH* corresponding to a given pMt may aid the design of desorptive mobilization experiments for certain metals as well as their adsorptive removal with the purpose of simulating metal adsorption and desorption cycles in real complex environments with changing groundwater pH. Copyright 1999 Academic Press. PMID:10049534

Apak; Hizal; Ustaer

1999-03-15

402

New Catalytic DNA Biosensors for Radionuclides and Metal ions  

SciTech Connect

The goals of the project are to develop new catalytic DNA biosensors for simultaneous detection and quantification of bioavailable radionuclides and metal ions, and apply the sensors for on-site, real-time assessment of concentration, speciation and stability of the individual contaminants during and after bioremediation. A negative selection strategy was tested and validated. In vitro selection was shown to yield highly active and specific transition metal ion-dependent catalytic DNA/RNA. A fluorescence resonance energy transfer (FRET) study of in vitro selected DNA demonstrated that the trifluorophore labeled system is a simple and powerful tool in studying complex biomolecules structure and dynamics, and is capable of revealing new sophisticated structural changes. New fluorophore/quenchers in a single fluorosensor yielded improved signal to noise ratio in detection, identification and quantification of metal contaminants. Catalytic DNA fluorescent and colorimetric sensors were shown useful in sensing lead in lake water and in leaded paint. Project results were described in two papers and two patents, and won an international prize.

Lu, Yi

2002-06-01

403

New Catalytic DNA Biosensors for Radionuclides and Metal ions  

SciTech Connect

The goals of the project are to develop new catalytic DNA biosensors for simultaneous detection and quantification of bioavailable radionuclides and metal ions, and apply the sensors for on-site, real-time assessment of concentration, speciation and stability of the individual contaminants during and after bioremediation. A negative selection strategy was tested and validated. In vitro selection was shown to yield highly active and specific transition metal ion-dependent catalytic DNA/RNA. A fluorescence resonance energy transfer (FRET) study of in vitro selected DNA demonstrated that the trifluorophore labeled system is a simple and powerful tool in studying complex biomolecules structure and dynamics, and is capable of revealing new sophisticated structural changes. New fluorophore/quenchers in a single fluorosensor yielded improved signal to noise ratio in detection, identification and quantification of metal contaminants. Catalytic DNA fluorescent and colorimetric sensors were shown useful in sensing lead in lake water and in leaded paint. Project results were described in two papers and two patents, and won an international prize.

Lu, Yi

2003-06-01

404

Amperometric microsensors for metal ion determination in single biological cells  

SciTech Connect

Amperometric microelectrode sensors were fabricated with the length and area of the electroactive surface tailored for the dimensions of the cells under investigation. A procedure for producing a sharpened carbon fiber sensor substrate was developed in order to avoid cell membrane rupture during single cell implantation. This carbon fiber sensor was then coated with a conductive polymeric porphyrin capable of the selective measurement of a specific metal ion. Differential pulse voltammetry was used for the determination of the concentration of the metal ions on the coated surface of the sensor. Tris(4-N-methylpyridyl)p-hydroxyphenylporphyrin was deposited on the surface of a carbon fiber ultramicroelectrode to measure Ca{sup 2+} concentration of 1 {times} 10{sup {minus}5} M in BHK-2/C-13 cells. Ni{sup 2+} at 1 {times} 10{sup {minus}6} M were measured in individual BC3H-T-myocytes, H4-IIC3 rat hepatoma or BHK-2/C-13 cells using ultramicroelectrodes coated with 3-methoxy-4-hydroxy-phenylporphyrin. In conclusion, these ultramicroelectrodes are capable of measuring the concentration of unbound Ni{sup 2+} and Ca{sup 2+} in the pathophysiologic range. The porphyrin ring may be modified by attaching different substituents with specificity for the coordination other metal cations.

Malinski, T.; Bailey, F.; Fish, J.R.; Kiechle, F. (Oakland Univ., Rochester, MI (United States) William Beaumont Hospital, Royal Oak, MI (United States))

1991-03-15

405

Hierarchically imprinted sorbents for the separation of metal ions  

SciTech Connect

Molecular imprinting involves arranging monomers of polymerization synthesis around a template molecule so that complexes between the monomer and template molecules are formed. Subsequent polymerization of the monomer molecules results in trapping template molecules in a highly cross-linked amorphous polymer matrix. Extraction of the imprint molecules leaves a predetermined arrangement of ligands and a tailored binding pocket. Such imprinted polymers have been used to mimic antibody functions to resolve racemates, and to separate mixtures of metal cations. Thus far, the organization of precursor monomers has been achieved mainly in inhomogeneous organic polymer matrices, with little control over structural parameters, such as pore sizes and surface areas. The authors report the first synthesis of imprinted hybrid sorbent materials with precise control of not only adsorption sites but also pore structures. The concepts behind multilevel imprinting are as follows. Surfactant micelles and metal ions both act as templates in these hierarchically imprinted sorbents. The metal ion and the surfactant are removed from the silica matrix via acid leaching and ethanol extraction, respectively. This results in the formation of different-sized imprints within the silica matrix, each with a specific function.

Dai, S.; Burleigh, M.C.; Ju, Y.H.; Gao, H.J.; Lin, J.S.; Pennycook, S.J.; Barnes, C.E.; Xue, Z.L.

2000-02-09

406

Global transport and localized layering of metallic ions in the upper atmosphere  

Microsoft Academic Search

A numerical model has been developed which is capable of simulating all phases of the life cycle of metallic ions, and results are described and interpreted herein for the typical case of Fe+ ions. This cycle begins with the initial deposition of metallics through meteor ablation and sputtering, followed by conversion of neutral Fe atoms to ions through photoionization and

L. N. Carter; J. M. Forbes

1999-01-01

407

The Effect of Complex Formation upon the Redox Potentials of Metallic Ions. Cyclic Voltammetry Experiments.  

ERIC Educational Resources Information Center

Describes experiments in which students prepare in situ soluble complexes of metal ions with different ligands and observe and estimate the change in formal potential that the ion undergoes upon complexation. Discusses student formation and analysis of soluble complexes of two different metal ions with the same ligand. (CW)

Ibanez, Jorge G.; And Others

1988-01-01

408

The Effect of Complex Formation upon the Redox Potentials of Metallic Ions. Cyclic Voltammetry Experiments.  

ERIC Educational Resources Information Center

|Describes experiments in which students prepare in situ soluble complexes of metal ions with different ligands and observe and estimate the change in formal potential that the ion undergoes upon complexation. Discusses student formation and analysis of soluble complexes of two different metal ions with the same ligand. (CW)|

Ibanez, Jorge G.; And Others

1988-01-01

409

Negative ion photoelectron spectroscopy of metal clusters, metal-organic clusters, metal oxides, and metal-doped silicon clusters  

NASA Astrophysics Data System (ADS)

The techniques of time-of-flight mass spectrometry and negative ion photoelectron spectroscopy were utilized to study metal clusters (Mgn -, Znn-, Can -, Mnn-, CuAln -, LiAln-, and NmSn n-), metal-organic complexes (Tin(benzene) m-, Fn(benzene)m- , Nin(benzene)m-), metal oxides(AuO-, PtO-, TaOn -, HfO2-, and MnnO -), and metal-doped semiconductor clusters (CrSin -, GdmSin- and HoSi n-). The study of magnesium and zinc cluster anions shows that they have magic numbers at size 9, 19 and 34, and the closures and reopenings of the s-p band gap are related to the mass spectra magic numbers. The evolution of electronic structure in Can clusters resembles that of Mgn - and Znn- with band gap closure and reopening. However, the electronic structures Can- clusters are more complicated and the magic numbers are different from those of Mgn- and Znn -. That might due to the involvement of calcium's empty d orbitals. In Mn clusters, a dramatic change of electronic structure was observed at Mn5-. The transition of metallic and magnetic properties is strongly related to the s-d hybridization. The photoelectron study of LiAln- is consistent with theoretical predictions, which described LiAl13 as alkali-halide-like ionic entity, Li+(Al13)-. The results of CuAln- show that copper atom might occupy interior position in these clusters. The results of Nam Snn- implied that Na4Sn 4 and NaSn5- could be described as (Na +)4Sn44- and (Na +)Sn52-, respectively. The formation of these species indicates the existence of Zintl phase structure in the gas phase. Tin(Bz)n+1- clusters have multiple-decker sandwich structures with each titanium atom located between two parallel benzene rings. The structures of Fen(Bz)m - and Nin(Bz)m- are characterized with a metal cluster core caged by benzene molecules. The information for the electronic states of PtO, AuO, and TaOn (n = 1--3) were obtained from the photoelectron spectra of their corresponding negative ions. The coincidence between electron affinity and thermodynamic stability was observed in the investigation of ZrO2 - and HfO2-. The studies of MnnO- revealed that addition of oxygen atom could change the magnetic momentum and magnetic coupling in the Mn clusters. The photoelectron spectra of CrSin- (n = 8--12) support the earlier theoretical calculations which found CrSi 12 to be an enhanced stability cluster with its chromium atom encapsulated inside a silicon cage and with its magnetic moment completely quenched by the effects of the surrounding cage. The preliminary results of GdSi n- show that GdSi4, GdSi6 and GdSi9 might be different from their counterparts.

Zheng, Weijun

410

Water purification from metal ions using carbon nanoparticle-conjugated polymer nanocomposites  

Microsoft Academic Search

The paper deals with a novel method of obtaining nanocarbon-conjugated polymer nanocomposites (NCPC) using nanocarbon colloids (NCC) and polyethylenimine (PEI) for water purification from metal ions. Size of NCC, process of NCPC synthesis, its chemical characteristics, ratio of NCC and PEI in NCPC, speed of coagulation of NCPC, mechanism of interaction of metal ions with NCPC, ability of removing metal

Rashid A. Khaydarov; Renat R. Khaydarov; Olga Gapurova

2010-01-01

411

Speciation in metal contaminated soils as revealed by an ion exchange resin membrane fractionation procedure  

Microsoft Academic Search

Ion exchangers have proven to be a useful tool in the study of metal speciation in aquatic environments, but have seen little application in the study of metal behavior in soil environments. The labile metal species in polluted soils were evaluated by equilibrating soil suspensions with ion exchange resin membranes of different types at pH values ranging from 3 to

J. Liang; J. J. Schoenau

1996-01-01

412

COMPARISON BETWEEN BIOSORBENTS FOR THE REMOVAL OF METAL IONS FROM AQUEOUS SOLUTIONS  

Microsoft Academic Search

This study compared the ability of a brown seaweed Ecklonia maxima, a dealginated seaweed waste, alginate fibre and waste linseed fibre to remove copper, nickel and cadmium from single and mixed metal ion solutions. All experiments were conducted using metal ion solutions of 10 mg\\/litre in concentration. The study has shown that alginate fibre generally exhibited the best overall metal

C. J. WILLIAMS; D. ADERHOLD; R. G. J. EDYVEAN

1998-01-01

413

COMPARATIVE IN VITRO EFFECTS OF SOME METAL IONS ON BOVINE KIDNEY CORTEX GLUTATHIONE REDUCTASE  

Microsoft Academic Search

Heavy metal pollution can arise from many sources and damage many organisms. Exposure to the metal ions can leads to a reduction in cellular antioxidant enzyme activities and lowers cellular defense against oxidative stress. In this study we have tested effects of the some metal ions on the purified bovine kidney cortex glutathione reductase (GR). Cadmium (Cd), nickel (Ni), and

Berivan Tandogan; N. Nuray Ulusu

2010-01-01

414

New fluorinated hydroxamic acid reagents for the extraction of metal ions with supercritical CO 2  

Microsoft Academic Search

Research to date on the supercritical fluid extraction (SFE) of metal ions has focused on the use of dithiocarbamates and ?-diketones. Hydroxamic acids are well known as effective chelating agents for a broad range of transition metal ions. Much attention has centred in inorganic chemistry on the effect of N-substitution on metal chelate stability and selectivity, and in analytical chemistry

J. D. Glennon; S. Hutchinson; A. Walker; S. J. Harris; C. C. McSweeney

1997-01-01

415

The Role of Metal Ion Polymerization in Beer's Law Deviations Using Extractive-Colorimetric Procedures  

Microsoft Academic Search

In the solvent extraction of metal chelates, the presence of polymerized metal ion in either the aqueous or organic layer, can cause the efficiency of extraction to vary throughout a range of metal ion concentrations. Should an extractive-colorimetric determination be employed, a deviation from Beer's Law can result in addition to other intrinsic causes. In this study, the nature of

Selman A. Berger

1990-01-01

416

The kinetics of sorption of divalent metal ions onto sphagnum moss peat  

Microsoft Academic Search

A pseudo-second order rate equation describing the kinetics of sorption of divalent metal ions onto sphagnum moss peat at different initial metal ion concentrations and peat doses has been developed. The kinetics of sorption were followed based on the amounts of metal sorbed at various time intervals. Results show that sorption (chemical bonding) might be rate-limiting in the sorption of

Y. S. Ho; G. McKay

2000-01-01

417

Removal and recovery of metal ions from process and waste streams using polymer filtration  

SciTech Connect

Polymer Filtration (PF) is an innovative, selective metal removal technology. Chelating, water-soluble polymers are used to selectively bind the desired metal ions and ultrafiltration is used to concentrate the polymer-metal complex producing a permeate with low levels of the targeted metal ion. When applied to the treatment of industrial metal-bearing aqueous process streams, the permeate water can often be reused within the process and the metal ions reclaimed. This technology is applicable to many types of industrial aqueous streams with widely varying chemistries. Application of PF to aqueous streams from nuclear materials processing and electroplating operations will be described.

Jarvinen, G.D.; Smith, B.F.; Robison, T.W.; Kraus, K.M.; Thompson, J.A.

1999-06-13

418

High-resolution mass spectrometer for liquid metal ion sources  

NASA Astrophysics Data System (ADS)

Recently, a mass spectrometer for liquid metal ion sources (LMIS) has been built and set into operation. This device uses an E × B-filter as mass dispersive element and provides sufficient resolution to analyse the emission of clusters from LMIS to much higher mass ranges (>2000 amu) than commercially available mass filters for focused ion beam systems. It has also been shown that for small masses the composition of clusters from different isotopes can be resolved. Furthermore, a rather high fluence of monodisperse clusters in the range of 106-107 clusters/s can be achieved with this setup. This makes it a promising tool for the preparation of mass selected clusters. In this contribution, theoretical considerations as well as technical details and the results of first measurements are presented.

Wortmann, Martin; Ludwig, Arne; Meijer, Jan; Reuter, Dirk; Wieck, Andreas D.

2013-09-01

419

Isobar separation by time-of-flight mass spectrometry for low-energy radioactive ion beam facilities  

Microsoft Academic Search

A multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS) system for low-energy radioactive ion beam facilities has been developed, which can be used for (i) isobar separation and (ii) direct mass measurements of very short-lived nuclei with half-lives of about 1ms or longer, and (iii) for identification and diagnosis of the ion beam by mass spectrometry. The system has been designed and simulated,

Wolfgang R. Plaß; Timo Dickel; Ulrich Czok; Hans Geissel; Martin Petrick; Katrin Reinheimer; Christoph Scheidenberger; Mikhail I. Yavor

2008-01-01

420

Coupled polaronic and ion transport in nanocrystalline metal oxide electrodes  

NASA Astrophysics Data System (ADS)

We report new computational methods and fundamental understanding in the dynamics of coupled charge and ion transport in nanoscale metal oxides. The methods attack the multi-scale problem of simulating the collective diffusivities of ions and charge compensating e-/h+ carriers in single crystal particles, across particle-particle grain boundaries, and through networks of grains for select systems. Methods include embedded quantum mechanical clusters at the DFT and MP2 levels of theory for atomic-scale polaronic and ion transport kinetics, classical DFT-based free energy calculations for grain-scale conductivity in the framework of the Poisson-Nernst-Planck formalism, and phase field simulation of charged particle diffusivity for conductivity at the grain network scale. This combination of approaches is one of a kind in terms of its multi-scale range, scaling, and computational efficiency. We are presently focused on coupled electron and Li+ ion transport in polymorphs of TiO2, and also in mixed valence spinel oxides, for electrode conductivity optimization and improving energy storage materials performance for Li+ batteries.

Rosso, Kevin

2012-02-01

421

Elastic scattering and total reaction cross sections with low-energy light radioactive ion beams.  

NASA Astrophysics Data System (ADS)

Elastic scattering experiments have being performed with low-energy radioactive ion beams produced by the RIBRAS facility in Sao Paulo, Brazil. Here I present the results for elastic scattering of 6He on several targets and light beams on 12C target. Special emphasis is given to the analysis of experiments were angular distributions for the elastic scattering of beryllium isotopes projectiles, 7Be, 9Be and 10Be, on a light target 12C were obtained. These elastic scattering angular distributions have been analysed in terms of optical model using the double-folding Sao Paulo potential. From this analysis, the total reaction cross section were also deduced and compared to the total reaction cross sections for many other light projectiles on 12C target. The comparison was made in terms of Universal Function reduction method.

Guimarães, Valdir

2011-10-01

422

A study of wet catalytic oxidation of radioactive spent ion exchange resin by hydrogen peroxide  

SciTech Connect

The decomposition behavior of cationic, anionic, and mixed ion-exchange resins was investigated in the H{sub 2}O{sub 2}-Ni{sup 2+}/Cu{sup 2+}, H{sub 2}O{sub 2}-Mn{sup 2+}/Cu{sup 2+}, H{sub 2}O{sub 2}-Fe{sup 2+}, H{sub 2}O{sub 2}-Cu{sup 2+}, and H{sub 2}O{sub 2}-Fe{sup 2+}/Cu{sup 2+} systems for volume reduction and improvement in the capacity of the cemented product. The effects on reaction processes and the consequences of many other factors were analyzed. No radioactivity was detected in the off-gas. The cementation process of encapsulation of the concentrated decomposition residue could produce qualified cemented products with excellent properties for long-term storage in a volume-reduced state.

Xingchao Jian; Tianbao Wu; Guichun Yun [Tsinghua Univ., Beijing (China)

1996-04-01

423

Tests of a Cryogenic Gas Cell for Radioactive Ion Beam Experiments  

NASA Astrophysics Data System (ADS)

The properties of resonances that dominate thermonuclear reaction rates on proton-rich, unstable nuclei can be probed using transfer reactions like (^3He,p). In inverse kinematics, this is achieved with a radioactive ion beam and a ^3He gas target. A cryogenic gas cell target for such experiments has been constructed at the Colorado School of Mines and tested at Oak Ridge National Laboratory with a stable ^17O beam. The gas cell design has been modified several times, and a number of techniques are being explored to reduce the significant yield from background reactions with the window material. Alternatively, a gas jet target with recycling capability could be a better solution to the long-term problem of using rare gases as targets. Results from our beam tests and future plans will be presented.

Chipps, K.; Bardayan, D.; Blackmon, J.; Chae, K.; Eastburg, J.; Greife, U.; Jones, K. L.; Kozub, R.; Livesay, R.; Moazen, B.; Nesaraja, C. D.; Pain, S.; Porter-Peden, M.; Sarazin, F.; Smith, M. S.

2006-10-01

424

Ion resist properties of thin films of transition metal oxides  

NASA Astrophysics Data System (ADS)

Properties of thin amorphous films of WO3, MoO3, V2O5 and a mixed WO3 + MoO3 compound as a high contrast, negative inorganic ion resist have been studied using ~ 10 keV Li+ and Na+ beams. With the latter two films, a significant improvement in the resist sensitivity is observed. The details of the exposure response curves of the four materials can be explained in terms of their original physical properties. The potential usefulness of this resist for both microfabrication and metallization in the submicron region is also presented.

Koshida, N.; Ichinose, Y.; Ohtaka, K.

1989-03-01

425

Electrolyte materials containing highly dissociated metal ion salts  

DOEpatents

The present invention relates to metal ion salts which can be used in electrolytes for producing electrochemical devices, including both primary and secondary batteries, photoelectrochemical cells and electrochromic displays. The salts have a low energy of dissociation and may be dissolved in a suitable polymer to produce a polymer solid electrolyte or in a polar aprotic liquid solvent to produce a liquid electrolyte. The anion of the salts may be covalently attached to polymer backbones to produce polymer solid electrolytes with exclusive cation conductivity.

Lee, Hung-Sui (East Setauket, NY); Geng, Lin (Coram, NY); Skotheim, Terje A. (Shoreham, NY)

1996-07-23

426

Metal-ion metathesis in metal-organic frameworks: a synthetic route to new metal-organic frameworks.  

PubMed

A porous metal-organic framework, Mn(H(3)O)[(Mn(4)Cl)(3)(hmtt)(8)] (POST-65), was prepared by the reaction of 5,5',10,10',15,15'-hexamethyltruxene-2,7,12-tricarboxylic acid (H(3)hmtt) with MnCl(2) under solvothermal conditions. POST-65(Mn) was subjected to post-synthetic modification with Fe, Co, Ni, and Cu according to an ion-exchange method that resulted in the formation of three isomorphous frameworks, POST-65(Co/Ni/Cu), as well as a new framework, POST-65(Fe). The ion-exchanged samples could not be prepared by regular solvothermal reactions. The complete exchange of the metal ions and retention of the framework structure were verified by inductively coupled plasma-atomic emission spectrometry (ICP-AES), powder X-ray diffraction (PXRD), and Brunauer-Emmett-Teller (BET) surface-area analysis. Single-crystal X-ray diffractions studies revealed a single-crystal-to-single-crystal (SCSC)-transformation nature of the ion-exchange process. Hydrogen-sorption and magnetization measurements showed metal-specific properties of POST-65. PMID:23154964

Kim, Yonghwi; Das, Sunirban; Bhattacharya, Saurav; Hong, Soonsang; Kim, Min Gyu; Yoon, Minyoung; Natarajan, Srinivasan; Kim, Kimoon

2012-11-14

427

Nuclear reactions with 11C and 14O radioactive ion beams  

SciTech Connect

Radioactive ion beams (RIBs) have been shown to be a useful tool for studying proton-rich nuclides near and beyond the proton dripline and for evaluating nuclear models. To take full advantage of RIBs, Elastic Resonance Scattering in Inverse Kinematics with Thick Targets (ERSIKTT), has proven to be a reliable experimental tool for investigations of proton unbound nuclei. Following several years of effort, Berkeley Experiments with Accelerated Radioactive Species (BEARS), a RIBs capability, has been developed at the Lawrence Berkeley National Laboratory's 88-Inch Cyclotron. The current BEARS provides two RIBs: a 11C beam of up to 2x108 pps intensity on target and an 14O beam of up to 3x104 pps intensity. While the development of the 11C beam has been relatively easy, a number of challenges had to be overcome to obtain the 14O beam. The excellent 11C beam has been used to investigate several reactions. The first was the 197Au(11C,xn)208-xnAt reaction, which was used to measure excitation functions for the 4n to 8n exit channels. The measured cross sections were generally predicted quite well using the fusion-evaporation code HIVAP. Possible errors in the branching ratios of ?? decays from At isotopes as well as the presence of incomplete fusion reactions probably contribute to specific overpredictions. 15F has been investigated by the p(14O,p)14O reaction with the ERSIKTT technology. Several 14O+p runs have been performed. Excellent energy calibration was obtained using resonances from the p(14N,p)14N reaction in inverse kinematics, and comparing the results to those obtained earlier with normal kinematics. The differences between 14N+p and 14O+p in the stopping power function have been evaluated for better energy calibration. After careful calibration, the energy levels of 15F were fitted with an R-matrix calculation. Spins and parities were assigned to the two observed resonances. This new measurement of the 15F ground state supports the disappearance of the Z = 8 proton magic number for odd Z, Tz=-3/2 nuclei. It is expected that future work on proton-rich nuclides will rely heavily on RIBs and/or mass separators. Currently, radioactive ion beam intensities are sufficient for the study of a reasonable number of very proton-rich nuclides.

Guo, Fanqing

2004-12-09

428

Removal of some radioactive nuclides by in-situ precipitation with ion exchange materials  

NASA Astrophysics Data System (ADS)

In-situ precipitation of some radwaste elements with cerium(IV)- and tin(IV) antimonates (134Cs, 60Co, 85Sr and 152, 154Eu) together with 10-4 M of each Cs+, Co2+, Sr2+ and/or Eu3+ have been prepared and found that all the product precipitates prefer the ions of smaller ionic radii. The distribution coefficients of Cs+, Co2+, Sr2+ and Eu3+ for all products were determined and it was found that the separation factors between neighbouring pairs of metal ions are larger on tin(IV) antimonate (SnSb) than cerium(IV) antimonate (CeSb). The adsorption of Cs+, Co2+, Sr2+ on CeSb and SnSb column beds was investigated and the preliminary results given here demonstrate the promise of potential applicability of these materials in many separations connected with nuclear fuel cycle activities.

El-Naggar, I. M.; Zakaria, E. S.; Abou-Mesalam, M. M.; Aly, H. F.

1999-01-01

429

Synthesis and characterization of novel nitrogen-containing ligands for metal ion separations  

NASA Astrophysics Data System (ADS)

A serious limiting factor in the continued development of nuclear power is the disposal of high-level radioactive waste from spent nuclear fuel. The PUREX process can be used for the recovery of U and Pu, but it does not separate the products of fission which are potentially useful, but currently cause most of our problems with radioactive waste. An important complicating factor is the presence of large amounts of lanthanides in dissolved spent nuclear fuel. The separation of lanthanides (Ln) from actinides (An) is therefore critical to the future of nuclear power. One approach to recovering these materials and decreasing the volume of the radioactive waste is the development of novel, highly selective organic ligands for the lanthanide and actinide ions. The focus of this dissertation is to design and synthesize new tridentate polyaza-ligands expected to exhibit affinity for first-row transition metals, lanthanides and actinides. In general, these chelating agents are structurally and functionally related to the pyridine and bipyridine bis-triazinyl compounds that have been investigated for potential application as separations agents for radioactive materials. Selected 1,2,3-triazoles have been synthesized using Sharpless' "Click Chemistry". Variation of the backbone and substituents on the triazole ring allows for facile modification of the cation binding pocket and phase compatibility properties of the new compounds. Characterization of the new ligands was performed using conventional analytical methods. Overall, the studies with three different ligands revealed useful information about the continuing effort of ligand design for actinide (III)/lanthanide (III) separations. Crystal structures established the purity of the organic molecules by showing that the PTMP and BDTP ligands are able to bind transition metals. Also, it was shown that the BDTB ligand was able to bind to Nd 3+ as observed from the spectrophotometric titrations and the calculated binding constant. To increase the lipophilicity of the ligand, the addition of an alkyl chain on the 4-position of the pyridine ring could be made. This confirms that scientists are advancing in the area of ligand design and hopefully one day the ligand with all of the desired characteristics will be used to close the nuclear fuel cycle.

Hoch, Cortney Leigh

430

Complexation of metal ion with poly(1-vinylimidazole) resin prepared by radiation-induced polymerization with template metal ion. [Gamma radiation  

SciTech Connect

Poly(1-vinylimidazole) (PVI) resin was prepared with Ni/sup 2 +/, CO/sup 2 +/, or Zn/sup 2 +/ as a template to study the adsorption of metal ions. The metal-1-vinylimidazole complex was copolymerized and cross-linked with 1-vinyl-2-pyrrolidone by ..gamma..-ray irradiation and the template metal ion was removed by treating the polymer complex with an acid. These PVI resins adsorbed metal ions more effectively than the PVI resin prepared without the template. The number of adsorption sites (As) and the stability constant (K) of Ni/sup 2 +/ complex were larger for the PVI resin prepared with the Ni ion template caused by the smaller dissociation rate constant of Ni ion from the resin. The composition of the Ni/sup 2 +/ complex in the resin remained constant. This suggests that the complexation proceeded via a one-step mechanism.

Kato, M. (Waseda Univ., Tokyo, Japan); Nishide, H.; Tsuchida, E.; Sasaki, T.

1981-07-01

431

Oxide Target Designs for High Primary Beam Intensities for Future Radioactive Ion Beam Facilities  

SciTech Connect

Oxide targets used nowadays in ISOL facilities can only accommodate up to a few kW incoming beam power because of the targets' moderate operation temperatures and their low thermal conductivities. A generic design to accommodate a 100 kW, 1 GeV proton beam, used as baseline parameters in the ongoing EURISOL-DS project, along with the numerical and experimental tools required for its validation, are reported here. We provide some details on these high-power composite oxide-refractory metal targets and on the proposed arrangement in several sub-units merging into a single ion source.

Stora, T.; Bouquerel, E.; Bruno, L.; Catherall, R.; Fernandes, S.; Kasprowicz, P.; Lettry, J.; Marzari, S.; Noah, E.; Penescu, L.; Wilfinger, R. [AB Department, CERN, CH-1211 Geneva 23 (Switzerland); Singh, B. S. Nara [Department of Physics, University of York, York, Y10 5DD (United Kingdom)

2009-03-10

432

Field-assisted ion diffusion of transition metals for the synthesis of nanocomposite silicate glasses  

Microsoft Academic Search

Field-assisted ion diffusion of metals was realized for the controlled doping of silicate glasses. Metallic films deposited onto the substrates by the rf-sputtering technique were used as the metal ions source. In particular, cobalt was, for the first time, introduced into a soda-lime glass by field-assisted ion exchange, giving rise to diffusion profiles that were observed to depend on the

F. Gonella; P. Canton; E. Cattaruzza; A. Quaranta; C. Sada; A. Vomiero

2006-01-01

433

Biosorption of metal ions from aqueous solution and tannery effluent by Bacillus sp. FM1  

Microsoft Academic Search

The metal binding capacity of Bacillus sp. FM1 isolated from soil irrigated with tannery effluent was assessed using synthetic metal solutions and tannery wastewater. Biosorption of Cr(VI) and Cu(II) ions from aqueous solutions using Bacillus was investigated as a function of pH, initial metal ion concentration and contact time. The optimum adsorption pH value observed for Cr(VI) and Cu(II) ions

Farhana Masood; Abdul Malik

2011-01-01

434

Effect of metal ions on the activity of green crab ( Scylla serrata) alkaline phosphatase  

Microsoft Academic Search

Green crab (Scylla serrata) alkaline phosphatase (EC 3.1.3.1) is a metalloenzyme, which catalyzes the nonspecific hydrolysis of phosphate monoesters. The present paper deals with the study of the effect of some kinds of metal ions on the enzyme. The positive monovalent alkali metal ions (Li+, Na+ and K+) have no effect on the enzyme; positive bivalent alkaline-earth metal ions (Mg2+,

Qing-Xi Chen; Wen-Zhu Zheng; Jing-Yu Lin; Yan Shi; Wen-Zhang Xie; Hai-Meng Zhou

2000-01-01

435

Effects of transition metal ions on positron annihilation characteristics in epoxies  

Microsoft Academic Search

Effects of several 3d-transition metal ions on positron annihilation characteristics in MY-720 epoxy resin have been investigated. All metal complexes were added at the mole ratio of 1 metal complex for every 10 MY-720 repeat units. In all cases, it appears that the 3d magnetic electrons are localized on their respective ions. Cr3+-ions make the strongest impact - both on

Jag J. Singh; Diane M. Stoakley; William H. Holt; Willis M. Mock; Joseph P. Teter

1987-01-01

436

Adsorption of some heavy metal ions on sulfate- and phosphate-modified kaolin  

Microsoft Academic Search

Kaolin (bright white lumps) from Ubulu-Ukwu in Delta State of Nigeria was modified with 200 ?g mL?1 of phosphate and sulphate anions to give phosphate- and sulfate-modified adsorbents, respectively. The adsorption of four metal ions (Pb2+, Cd2+, Zn2+, and Cu2+) was studied as a function of metal ions concentration.The metal ions showed stronger affinity for the phosphate-modified adsorbent with Pb2+,

K. O. Adebowale; I. E. Unuabonah; B. I. Olu-Owolabi

2005-01-01

437

Selective exchange of divalent transition metal ions in cryptomelane-type manganic acid with tunnel structure  

SciTech Connect

The ion-exchange selectivity of divalent transition metal ions on cryptomelane-type manganic acid (CMA) with tunnel structure has been studied using the distribution coefficients ([ital K][sub [ital d

Tsuji, M. (Department of Chemistry, Faculty of Science, Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro-ku, Tokyo 152 (Japan)); Komarneni, S. (Materials Research Laboratory and Department of Agronomy, The Pennsylvania State University, University Park, Pennsylvania 16802-4801 (United States))

1993-03-01

438

Optical column design with liquid metal ion sources  

SciTech Connect

We have applied the results of our studies of fundamental properties of liquid metal ion (LMI) sources to the design of an optical system which exploits their unique characteristics. A gun with a beam current regulating system, a three-element asymmetric electrostatic lens, and an einzel lens were incorporated into an optical column with a six-pole electrostatic stigmator and post-lens deflection. A design consideration with LMI sources is that material sputtered from apertures near the source can ''poison'' it, leading to source instability and short life. This problem can be avoided by large source-lens spacing, but we have chosen to place the source close enough to the lens aperture that virtually no ion current strikes it, resulting in stable operation. While close source-lens aperture spacing normally requires an undesirably low (approx.5 kV) voltage on the source to achieve the conditions for ion emission, we have overcome the problem by surrounding the source with a grid (similar to a Wehnelt) maintained near source potential. The shielding action of the grid allows source operation at voltages in the range 15--20 kV with a 2-mm spacing between source and lens aperture. In addition, by biasing the grid with respect to the source, the ion current can be varied while maintaining constant ion beam energy. The beam voltage can then be varied by using the variable voltage properties of the asymmetric lens. A LMI Ga source has been operated with low total current I/sub t/<3 ..mu..A, corresponding to an angular intensity dI/drroughly-equal20 A sr/sup -1/ and a beam energy spread Eroughly-equal5 eV. With a beam energy of 16 keV, 2-nA current was focused into 4000 A at a working distance of roughly-equal80 mm from the final lens.

Orloff, J.; Swanson, L.W.

1981-11-01

439

Selective removal of the heavy metal ions from waters and industrial wastewaters by ion-exchange method  

Microsoft Academic Search

By ion exchange undesirable ions are replaced by others which don't contribute to contamination of the environment. The method is technologically simple and enables efficient removal of even traces of impurities from solutions. Examples of selective removal of heavy metal ions by ion-exchange are presented. They include removal of Pb(II), Hg(II), Cd(II), Ni(II), V(IV,V), Cr(III,VI), Cu(II) and Zn(II) from water

Z. Hubicki; P. Podko?cielny; E. Robens

2004-01-01

440

Dissecting the metal selectivity of MerR monovalent metal ion sensors in Salmonella.  

PubMed

Two homologous transcription factors, CueR and GolS, that belong to the MerR metalloregulatory family are responsible for Salmonella Cu and Au sensing and resistance, respectively. They share similarities not only in their sequences, but also in their target transcription binding sites. While CueR responds similarly to Au, Ag, or Cu to induce the expression of its target genes, GolS shows higher activation by Au than by Ag or Cu. We showed that the ability of GolS to distinguish Au from Cu resides in the metal-binding loop motif. Here, we identify the amino acids within the motif that determine in vivo metal selectivity. We show that residues at positions 113 and 118 within the metal-binding loop are the main contributors to metal selectivity. The presence of a Pro residue at position 113 favors the detection of Cu, while the presence of Pro at position 118 disfavors it. Our results highlight the molecular bases that allow these regulators to coordinate the correct metal ion directing the response to a particular metal injury. PMID:23645605

Ibáñez, María M; Cerminati, Sebastián; Checa, Susana K; Soncini, Fernando C

2013-05-03