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1

Radioactive Ion Sources  

E-print Network

This chapter provides an overview of the basic requirements for ion sources designed and operated in radioactive ion beam facilities. The facilities where these sources are operated exploit the isotope separation online (ISOL) technique, in which a target is combined with an ion source to maximize the secondary beam intensity and chemical element selectivity. Three main classes of sources are operated, namely surface-type ion sources, arc discharge-type ion sources, and finally radio-frequency-heated plasma-type ion sources.

Stora, T

2014-01-01

2

Radioactive ion detector  

DOEpatents

Apparatus for detecting the presence, in aqueous media, of substances which emit alpha and/or beta radiation and determining the oxidation state of these radioactive substances, that is, whether they are in cationic or anionic form. In one embodiment, a sensor assembly has two elements, one comprised of an ion-exchange material which binds cations and the other comprised of an ion-exchange material which binds anions. Each ion-exchange element is further comprised of a scintillation plastic and a photocurrent generator. When a radioactive substance to which the sensor is exposed binds to either element and emits alpha or beta particles, photons produced in the scintillation plastic illuminate the photocurrent generator of that element. Sensing apparatus senses generator output and thereby indicates whether cationic species or anionic species or both are present and also provides an indication of species quantity.

Bower, Kenneth E. (Los Alamos, NM); Weeks, Donald R. (Saratoga, CA)

1997-01-01

3

Radioactive ion detector  

DOEpatents

Apparatus for detecting the presence, in aqueous media, of substances which emit alpha and/or beta radiation and determining the oxidation state of these radioactive substances, that is, whether they are in cationic or anionic form. In one embodiment, a sensor assembly has two elements, one comprised of an ion-exchange material which binds cations and the other comprised of an ion-exchange material which binds anions. Each ion-exchange element is further comprised of a scintillation plastic and a photocurrent generator. When a radioactive substance to which the sensor is exposed binds to either element and emits alpha or beta particles, photons produced in the scintillation plastic illuminate the photocurrent generator of that element. Sensing apparatus senses generator output and thereby indicates whether cationic species or anionic species or both are present and also provides an indication of species quantity. 2 figs.

Bower, K.E.; Weeks, D.R.

1997-08-12

4

Charge Breeding of Radioactive Ions  

E-print Network

Charge breeding is a technique to increase the charge state of ions, in many cases radioactive ions. The singly charged radioactive ions, produced in an isotope separator on-line facility, and extracted with a low kinetic energy of some tens of keV, are injected into a charge breeder, where the charge state is increased to Q. The transformed ions are either directed towards a dedicated experiment requiring highly charged ions, or post-accelerated to higher beam energies. In this paper the physics processes involved in the production of highly charged ions will be introduced, and the injection and extraction beam parameters of the charge breeder defined. A description of the three main charge-breeding methods is given, namely: electron stripping in gas jet or foil; external ion injection into an electron-beam ion source/trap (EBIS/T); and external ion injection into an electron cyclotron resonance ion source (ECRIS). In addition, some preparatory devices for charge breeding and practical beam delivery aspects ...

Wenander, F J C

2013-01-01

5

Radioactive Ion Beams and Radiopharmaceuticals  

NASA Astrophysics Data System (ADS)

Experiments performed at radioactive ion beam facilities shed new light on nuclear physics and nuclear structure, as well as nuclear astrophysics, materials science and medical science. The many existing facilities, as well as the new generation of facilities being built and those proposed for the future, are a testament to the high interest in this rapidly expanding field. The opportunities inherent in radioactive beam facilities have enabled the search for radioisotopes suitable for medical diagnosis or therapy. In this article, an overview of the production techniques and the current status of RIB facilities and proposals will be presented. In addition, accelerator-generated radiopharmaceuticals will be reviewed.

Laxdal, R. E.; Morton, A. C.; Schaffer, P.

2014-02-01

6

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

7

Illuminating Metal Ion Sensors - Benzimidazolesulfonamide Metal Complexes  

PubMed Central

The synthesis, structure, and solution spectroscopy of several 2-sulfonamidophenylbenzimidazole metal complexes is reported. These ligands, which have been reported as selective molecular sensors for Zn2+, readily form complexes with Co2+, Ni2+, Cu2+, and Zn2+. Surprisingly, the ligand adopts different binding modes depending on the metal ion. The work here provides insight into the coordination chemistry of these ligands that may allow for the development of improved metal ion sensors and metalloprotein inhibitors. PMID:20942382

Martin, David; Rouffet, Matthieu

2010-01-01

8

Status report on the Holifield Radioactive Ion Beam Project  

Microsoft Academic Search

In July 1992, a project was started to reconfigure the Holifield Heavy Ion Research Facility (HHIRF) to form the Holifield Radioactive Ion Beam Facility (HRIBF). This ORNL project to produce medium-intensity, proton-rich, radioactive ion beams (RIBS) for astrophysics, nuclear physics, and applied research was first described to the SNEAP community at Chalk River in 1992. To briefly review, radioactive ions

M. J. Meigs; G. D. Alton; R. L. Auble

1994-01-01

9

Co-axial ECR plasma system for radioactive ion implantation  

NASA Astrophysics Data System (ADS)

A pulsed, co-axial electron cyclotron resonance (ECR, 2.45 GHz) plasma reactor was designed and tested to demonstrate the feasibility of plasma-based radioactive ion implantation (32P radioisotope). The geometry of the reactor was designed to produce an efficient implantation of cylindrical implants. Therefore, the reactor is cylindrical in shape, and is equipped with a cylindrical grid in a co-axial geometry. The plasma is created between the wall and the grid; the plasma surrounds the implant, allowing for a radial implantation. A 1 ms microwave pulse creates a plasma in argon, which sputters material from a radioactive cathode. A fraction of the radioisotopes is then ionized, and the ions are implanted into negatively biased metal samples. The plasma was characterized by means of electrostatic probes, giving spatial evaluations of the electron temperature, plasma potential and electron density. Titanium samples were implanted with 32P during a study that aimed at optimizing the position of the radioactive sputter cathode in the plasma. From an analysis of the distribution of the radioactive fragments, we deduce that the plasma potential has a marked effect on the ion trajectories. In particular, it provides a more uniform implantation distribution than one would otherwise expect. For plasma densities ~8 × 1010 cm-3, implantation efficiencies as high as 1% are measured; this is about 100 times higher than conventional beam-line ion implantation.

Fortin, M. A.; Marion, F.; Stansfield, B.; Paynter, R. W.; Sarkar, D.; Sarkissian, A.; Terreault, B.

2005-08-01

10

Radioactive Ion Beams for Stewardship Science  

NASA Astrophysics Data System (ADS)

Measurements of particular reaction sequences that influence the cumulative fission yield of specific fission products of interest for stewardship science as well as for nuclear reactions on radiochemical detectors used in testing nuclear devices are often not accessible with radioactive targets because of short half-lives, high specific activities or availability of sufficient target material. Therefore, a possible surrogate reaction for (n,?) is the neutron transfer in (d,p) or (d,p?) reactions, which can be measured with ion beams of short-lived radioactive species in inverse kinematics. The Center of Excellence for Radioactive Ion Beam Studies for Stewardship Science is developing experimental techniques for measuring (d,p) reactions. Therefore, a strong component of our center is the development of accelerated radioactive ion beams such as 48V, 73,74As, 92,94,95Sr, 82Ge, 132,134Sn, Zr, Mo, Tc, and others. Some of these beams had not been available before, because the elements are refractory, or some beams require higher beam intensity or purity. Beam development techniques include different actinide targets, e.g. ThO2, molecular sideband formation, e.g. for Sr and possibly charge-exchange processes. This talk will consider specific beams of interested for our center. This research was sponsored by the NNSA under Stewardship Science Academic Alliance program through DOE Cooperative Agreement # DE-FC03-3NA00143.

Kronenberg, Andreas; Carter, H. K.; Spejewski, E. H.

2006-10-01

11

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

12

Radioactive Ion Beam Production Capabilities at the Holifield Radioactive Ion Beam Facility  

SciTech Connect

The Holifield Radioactive Ion Beam Facility (HRIBF) is a national user facility for research with radioactive ion beams (RIBs) that has been in routine operation since 1996. It is located at Oak Ridge National Laboratory (ORNL) and operated by the ORNL Physics Division. The principal mission of HRIBF is the production of high-quality beams of short-lived radioactive isotopes to support research in nuclear structure physics and nuclear astrophysics. HRIBF is currently unique worldwide in its ability to provide neutron-rich fission fragment beams post-accelerated to energies above the Coulomb barrier for nuclear reactions.

Beene, James R [ORNL; Dowling, Darryl T [ORNL; Gross, Carl J [ORNL; Juras, Raymond C [ORNL; Liu, Yuan [ORNL; Meigs, Martha J [ORNL; Mendez, II, Anthony J [ORNL; Nazarewicz, Witold [ORNL; Sinclair, John William [ORNL; Stracener, Daniel W [ORNL; Tatum, B Alan [ORNL

2011-01-01

13

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

14

Storage rings for radioactive ion beams  

NASA Astrophysics Data System (ADS)

Storage rings for radioactive heavy ions can be applied for a wide range of experiments in atomic and nuclear physics. The rare isotope beams are produced in flight via fragmentation or fission of high-intensity primary ions and they circulate in the storage ring at moderately relativistic energies (typically between 0.1 GeV/u up to 1 GeV/u). Due to their production mechanism they are usually highly charged or even fully stripped. The circulating radioactive heavy ion beams can be used to measure nuclear properties such as masses and decay times, which, in turn, can depend strongly on the ionic charge state. The storage rings must have large acceptances and dynamic apertures. The subsequent application of stochastic precooling of the secondary ions which are injected with large transverse and longitudinal emittances, and electron cooling to reach very high phase space densities has turned out to be a helpful tool for experiments with short-lived ions having lifetimes down to a few seconds. Some of these experiments have already been performed at the experimental storage ring ESR at GSI. The storage ring complex of the FAIR project is intended to enhance significantly the range of experimental possibilities. It is planned to extend the scope of experimental possibilities to collisions with electron or antiproton beams.

Nolden, F.; Dimopoulou, C.; Dolinskii, A.; Steck, M.

2008-10-01

15

A radioactive ion beam facility using photofission  

Microsoft Academic Search

Use of a high-power electron linac as the driver accelerator for a Radioactive Ion Beam (RIB) facility is proposed. An electron beam of 30MeV and 100kW can produce nearly 5×1013 fissions\\/s from an optimized 235U target and about 60% of this from a natural uranium target. An electron beam can be readily transmitted through a thin window at the exit

William T Diamond

1999-01-01

16

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

17

Laser ion source development at Holifield Radioactive Ion Beam Facilitya)  

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

18

Radioactive Ion Beam Purification by Selective Adsorption  

NASA Astrophysics Data System (ADS)

Isobaric contaminations in ISOL beams are a recurrent problem in nuclear physics experiments. Surface effects in the transfer line between target and ion source can be employed to achieve additional selectivity. Since interactions of the atoms' outer electrons with the surface determine adsorption behavior it can change drastically within an isobaric chain, introducing a chemical selectivity. Quartz transfer lines are currently applied at ISOLDE to reduce alkali contaminations [1]. We will conduct an on-line study of the adsorption behavior of fission products on a range of materials stable at high temperatures. Therefore a special target--ion source unit with a variable-temperature transfer line and interchangeable liner has been constructed in collaboration with the ISOLDE technical group. Results of first tests using new adsorption materials at the on-line separator test facility at Holifield Radioactive Ion Beam Facility, ORNL, will be presented. [1] Bouquerel et al., Europ. Phys. J. -- Spec. Top. 150, 277 (2006)

Jost, C.; Carter, H. K.; Griffith, B. O.; Reed, C. A.; Kratz, K.-L.; Stora, T.; Stracener, D. W.

2008-10-01

19

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

20

INEL metal recycle radioactive scrap metal survey report  

SciTech Connect

DOE requested that inventory and characterization of radioactive scrap metal (RSM) be conducted across the DOE complex. Past studies have estimated the metal available from unsubstantiated sources. In meetings held in FY-1993, with seven DOE sites represented and several DOE-HQ personnel present, INEL personnel discovered that these numbers were not reliable and that large stockpiles did not exist. INEL proposed doing in-field measurements to ascertain the amount of RSM actually available. This information was necessary to determine the economic viability of recycling and to identify feed stock that could be used to produce containers for radioactive waste. This inventory measured the amount of RSM available at the selected DOE sites. Information gathered included radionuclide content and chemical form, general radiation field, alloy type, and mass of metal.

Funk, D.M.

1994-09-01

21

Development of metallic ion beams using ECRIS  

Microsoft Academic Search

The low energy metallic ion beams find wide applications in various research fields of the materials science. Several metallic ion beams have been developed successfully using the electron cyclotron resonance (ECR) ion source based low energy ion beam facility (LEIBF) at Inter University Accelerator Centre (IUAC), New Delhi. These metallic ion beams were developed by different techniques and utilized for

P. Kumar; G. Rodrigues; P. S. Lakshmy; D. Kanjilal; Beer Pal Singh; R. Kumar

2006-01-01

22

Radioactive Ion Beam Production Capabilities At The Holifield Radioactive Ion Beam Facility  

NASA Astrophysics Data System (ADS)

The Holifield Radioactive Ion Beam Facility (HRIBF) is a national user facility for research with radioactive ion beams (RIBs) that has been in routine operation since 1996. It is located at Oak Ridge National Laboratory (ORNL) and operated by the ORNL Physics Division. The principal mission of the HRIBF is the production of high quality beams of shortlived radioactive isotopes to support research in nuclear structure physics and nuclear astrophysics. HRIBF is currently unique worldwide in its ability to provide neutron-rich fission fragment beams post-accelerated to energies above the Coulomb barrier for nuclear reactions. HRIBF produces RIBs by the isotope separator on-line (ISOL) technique using a particle accelerator system that consists of the Oak Ridge Isochronous Cyclotron (ORIC) driver accelerator, one of the two Injectors for Radioactive Ion Species (IRIS1 or IRIS2) production systems, and the 25-MV tandem electrostatic accelerator that is used for RIB post-acceleration. ORIC provides a light ion beam (proton, deuteron, or alpha) which is directed onto a thick target mounted in a target-ion source (TIS) assembly located on IRIS1 or IRIS2. Radioactive atoms that diffuse from the target material are ionized, accelerated, mass selected, and transported to the tandem accelerator where they are further accelerated to energies suitable for nuclear physics research. RIBs are transported through a beam line system to various experimental end stations including the Recoil Mass Spectrometer (RMS) for nuclear structure research, and the Daresbury Recoil Separator (DRS) for nuclear astrophysics research. HRIBF also includes two off-line ion source test facilities, one low-power on-line ISOL test facility (OLTF), and one high-power on-line ISOL test facility (HPTL). This paper provides an overview and status update of HRIBF, describes the recently completed 4.7M IRIS2 addition and incorporation of laser systems for beam production and purification, and discusses a proposed replacement of the ORIC driver accelerator.

Beene, J. R.; Dowling, D. T.; Gross, C. J.; Juras, R. C.; Liu, Y.; Meigs, M. J.; Mendez, A. J.; Nazarewicz, W.; Sinclair, J. W.; Stracener, D. W.; Tatum, B. A.

2011-06-01

23

Radioactive Ion Beam Production Capabilities At The Holifield Radioactive Ion Beam Facility  

SciTech Connect

The Holifield Radioactive Ion Beam Facility (HRIBF) is a national user facility for research with radioactive ion beams (RIBs) that has been in routine operation since 1996. It is located at Oak Ridge National Laboratory (ORNL) and operated by the ORNL Physics Division. The principal mission of the HRIBF is the production of high quality beams of shortlived radioactive isotopes to support research in nuclear structure physics and nuclear astrophysics. HRIBF is currently unique worldwide in its ability to provide neutron-rich fission fragment beams post-accelerated to energies above the Coulomb barrier for nuclear reactions. HRIBF produces RIBs by the isotope separator on-line (ISOL) technique using a particle accelerator system that consists of the Oak Ridge Isochronous Cyclotron (ORIC) driver accelerator, one of the two Injectors for Radioactive Ion Species (IRIS1 or IRIS2) production systems, and the 25-MV tandem electrostatic accelerator that is used for RIB post-acceleration. ORIC provides a light ion beam (proton, deuteron, or alpha) which is directed onto a thick target mounted in a target-ion source (TIS) assembly located on IRIS1 or IRIS2. Radioactive atoms that diffuse from the target material are ionized, accelerated, mass selected, and transported to the tandem accelerator where they are further accelerated to energies suitable for nuclear physics research. RIBs are transported through a beam line system to various experimental end stations including the Recoil Mass Spectrometer (RMS) for nuclear structure research, and the Daresbury Recoil Separator (DRS) for nuclear astrophysics research. HRIBF also includes two off-line ion source test facilities, one low-power on-line ISOL test facility (OLTF), and one high-power on-line ISOL test facility (HPTL). This paper provides an overview and status update of HRIBF, describes the recently completed $4.7M IRIS2 addition and incorporation of laser systems for beam production and purification, and discusses a proposed replacement of the ORIC driver accelerator.

Beene, J. R.; Dowling, D. T.; Gross, C. J.; Juras, R. C.; Liu, Y.; Meigs, M. J.; Mendez, A. J. II; Nazarewicz, W.; Sinclair, J. W.; Stracener, D. W.; Tatum, B. A. [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

2011-06-01

24

The ORNL Radioactive Ion Beam Project  

SciTech Connect

On June 30, 1992, the Holifield Heavy Ion Research Facility (HHIRF) was shut down as an operating national users' facility for heavy ion physics research and became a construction project to reconfigure the existing accelerator system and develop a first generation radioactive ion beam (RIB) facility. During its 11 years of operation, the HHIRF had over 600 users, of which 200 were graduate students. During this time, nearly 39,000 hours of beam were delivered as beam-on-target for nuclear, atomic, and applied research. All together, 69 different isotopes from 36 different elements were accelerated for scheduled experiments. Most beams were produced with only the 25-MV tandem accelerator; however, for the most energetic beams and the heaviest ions, the Oak Ridge Isochronous Cyclotron (ORIC) was used as an energy booster. This paper will briefly review the concept of the ORNL RIB project and describe the progress being made on the various hardware components and physics factors required to produce RiBs with the HHIRF accelerator system.

Olsen, D.K.; Alton, G.D.; Auble, R.L.; Baktash, C.; Dowling, D.T.; Garrett, J.D.; Haynes, D.L.; Jones, C.M.; Juras, R.C.; Lane, S.N.; Meigs, M.J.; Mills, G.D.; Mosko, S.W.; Robinson, R.L.; Tatum, B.A. (Oak Ridge National Lab., TN (United States)); Blosser, H.; Lee, L.; Marti, F. (Michigan State Univ., East Lansing, MI (United States)); Carter, H.K.; Kormicki, J.; Mantica, P.; Rayburn, L.; Reed, C.A. (Oak Ridge Assoc

1992-01-01

25

The ORNL Radioactive Ion Beam Project  

SciTech Connect

On June 30, 1992, the Holifield Heavy Ion Research Facility (HHIRF) was shut down as an operating national users` facility for heavy ion physics research and became a construction project to reconfigure the existing accelerator system and develop a first generation radioactive ion beam (RIB) facility. During its 11 years of operation, the HHIRF had over 600 users, of which 200 were graduate students. During this time, nearly 39,000 hours of beam were delivered as beam-on-target for nuclear, atomic, and applied research. All together, 69 different isotopes from 36 different elements were accelerated for scheduled experiments. Most beams were produced with only the 25-MV tandem accelerator; however, for the most energetic beams and the heaviest ions, the Oak Ridge Isochronous Cyclotron (ORIC) was used as an energy booster. This paper will briefly review the concept of the ORNL RIB project and describe the progress being made on the various hardware components and physics factors required to produce RiBs with the HHIRF accelerator system.

Olsen, D.K.; Alton, G.D.; Auble, R.L.; Baktash, C.; Dowling, D.T.; Garrett, J.D.; Haynes, D.L.; Jones, C.M.; Juras, R.C.; Lane, S.N.; Meigs, M.J.; Mills, G.D.; Mosko, S.W.; Robinson, R.L.; Tatum, B.A. [Oak Ridge National Lab., TN (United States); Blosser, H.; Lee, L.; Marti, F. [Michigan State Univ., East Lansing, MI (United States); Carter, H.K.; Kormicki, J.; Mantica, P.; Rayburn, L.; Reed, C.A. [Oak Ridge Associated Universities, Inc., TN (United States); Dellwo, J. [Joint Inst. for Heavy Ion Research, Oak Ridge, TN (United States); Wollnik, H. [Giessen Univ. (Germany)

1992-12-31

26

Transport and extraction of radioactive ions stopped in superfluid helium  

NASA Astrophysics Data System (ADS)

A new approach to convert a high energy beam to a low energy one, which is essential for the next generation radioactive ion beam facilities, has been proposed and tested at Jyväskylä, Finland. An open 223Ra alpha-decay-recoil source has been used to produce radioactive ions in superfluid helium. The alpha spectra demonstrate that the recoiling 219Rn ions have been extracted out of liquid helium. This first observation of the extraction of heavy positive ions across the superfluid helium surface was possible thanks to the high sensitivity of radioactivity detection. An efficiency of 36% was obtained for the ion extraction out of liquid helium.

Huang, W. X.; Dendooven, P.; Gloos, K.; Takahashi, N.; Arutyunov, K.; Pekola, J. P.; Äystö, J.

2003-05-01

27

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

28

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.

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

1986-10-20

29

Metal ions in circumgalactic medium  

NASA Astrophysics Data System (ADS)

Recent observations show high column densities of metal ions in extended halos of galaxies in the redshift range z˜ 0-3. Interpretation of these observations is critically sensitive to a model of ionization state of the circumgalactic gas. In order to explain observed OVI column densities models with thermal ionization equilibrium require metallicity of the halo gas to be as high as the solar one. As a consequence such extended halos would become the main reservouir of metals and missing. On the other hand, when a time-dependent radiation field of a nearby starburst galaxy is assumed to be the main ionization source observational OVI absorption data can be explained if the circumgaactic halos contain an order of magnitude lower amount of metals. Such a difference is due to a much lower fraction of OVI ions (f(OVI)˜ 0.1) under the thermal collisional ionization equilibrium than reached (typically f(OVI)? 0.4-0.6) in a time-dependent radiation field from the underlying star-forming galaxy superimposed on to the extragalactic background. Therefore we argue that high column densities of OVI recently observed in the halos of staforming galaxies even for low (˜ 0.1 Z_?) metallicities. As a result, the requirements to the sources of oxygen in such extended halos relax to a reasonably conservative level. We discuss a possibility of more advanced study of metal ions in extended galactic haloes using the WSO/Spectrum-UV facility.

Vasiliev, Evgenii; Ryabova, Marina; Shchekinov, Yuri

30

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

31

Scrap metals industry perspective on radioactive materials.  

PubMed

With more than 80 reported/confirmed accidental melts worldwide since 1983 and still counting, potential contamination by radioactive materials remains as a major concern among recycled scrap and steel companies. Some of these events were catastrophic and have cost the industry millions of dollars in business and, at the same time, resulted in declining consumer confidence. It is also known that more events with confirmed radioactive contamination have occurred that involve mining of old steel slag and skull dumps. Consequently, the steel industry has since undergone massive changes that incurred unprecedented expenses through the installation of radiation monitoring systems in hopes of preventing another accidental melt. Despite such extraordinary efforts, accidental melts continue to occur and plague the industry. One recent reported/confirmed event occurred in the Republic of China in 2004, causing the usual lengthy shutdown for expensive decontamination efforts before the steel mill could resume operations. With this perspective in mind, the metal industry has a long-standing opposition to the release of radioactive materials of any kind to commerce for fear of contamination and the potential consequences. PMID:17033460

Turner, Ray

2006-11-01

32

Metal ion-containing epoxies  

NASA Technical Reports Server (NTRS)

A variety of metallic and organometallic complexes to be used as potential additives for an epoxy used by the aerospace industry as a composite matrix resin were investigated. A total of 9 complexes were screened for compatibility and for their ability to accelerate or inhibit the cure of a highly crosslinkable epoxy resin. Methods for combining the metallic complexes with the resin were investigated, gel times recorded, and cure exotherms studied by differential scanning calorimetry. Glass transition temperatures of cured metal ion containing epoxy castings were determined by thermomechanical analysis. Thermal stabilities of the castings were determined by thermogravimetric analysis. Mechanical strength and stiffness of these doped epoxies were also measured.

Stoakley, D. M.; St.clair, A. K.

1982-01-01

33

Development of the Holifield Radioactive Ion Beam Facility  

SciTech Connect

The Holifield Radioactive Ion Beam Facility (HRIBF) construction project has been completed and the first radioactive ion beam has been successfully accelerated. The project, which began in 1992, has involved numerous facility modifications. The Oak Ridge Isochronous Cyclotron has been converted from an energy booster for heavy ion beams to a light ion accelerator with internal ion source. A target-ion source and mass analysis system have been commissioned as key components of the facility`s radioactive ion beam injector to the 25MV tandem electrostatic accelerator. Beam transport lines have been completed, and new diagnostics for very low intensity beams have been developed. Work continues on a unified control system. Development of research quality radioactive beams for the nuclear structure and nuclear astrophysics communities continues. This paper details facility development to date.

Tatum, B.A.

1997-08-01

34

The ORNL radioactive ion beam project with the ORIC accelerator  

SciTech Connect

The ORNL project to produce medium-intensity, proton-rich, radioactive ion beams (RIBS) for astrophysics, nuclear physics, and applied research with the Holifield Heavy Ion Research Facility (HHIRF) accelerators has been approved. Radioactive atoms will be produced by fusion reactions in an Isotope Separator On-Line (ISOL)type target-ion source assembly using light ion beams from the Oak Ridge Isochronous Cyclotron (ORIC). The radioactive atoms will be converted to negative ions using either (1) direct-surface ionization or (2) charge exchange following positive ionization. After acceleration to approximately 300 keV from a high-voltage platform, these negative ions will be injected into the 25-MV tandem accelerator for acceleration to higher energies. Beams of up to mass 80 will be accelerated to energies greater than 5 MeV/nucleon. For some radioactive beams. intensities greater than I pnA are possible.

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.; Kormicki, J. (Oak Ridge Associated Universities, Inc., TN (United States))

1992-01-01

35

The ORNL radioactive ion beam project with the ORIC accelerator  

SciTech Connect

The ORNL project to produce medium-intensity, proton-rich, radioactive ion beams (RIBS) for astrophysics, nuclear physics, and applied research with the Holifield Heavy Ion Research Facility (HHIRF) accelerators has been approved. Radioactive atoms will be produced by fusion reactions in an Isotope Separator On-Line (ISOL)type target-ion source assembly using light ion beams from the Oak Ridge Isochronous Cyclotron (ORIC). The radioactive atoms will be converted to negative ions using either (1) direct-surface ionization or (2) charge exchange following positive ionization. After acceleration to approximately 300 keV from a high-voltage platform, these negative ions will be injected into the 25-MV tandem accelerator for acceleration to higher energies. Beams of up to mass 80 will be accelerated to energies greater than 5 MeV/nucleon. For some radioactive beams. intensities greater than I pnA are possible.

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.; Kormicki, J. [Oak Ridge Associated Universities, Inc., TN (United States)

1992-09-01

36

A radioactive ion beam facility using photofission  

NASA Astrophysics Data System (ADS)

Use of a high-power electron linac as the driver accelerator for a Radioactive Ion Beam (RIB) facility is proposed. An electron beam of 30 MeV and 100 kW can produce nearly 5×10 13 fissions/s from an optimized 235U target and about 60% of this from a natural uranium target. An electron beam can be readily transmitted through a thin window at the exit of the accelerator vacuum system and transported a short distance through air to a water-cooled Bremsstrahlung-production target. The Bremsstrahlung radiation can, in turn, be transported through air to the isotope-production target. This separates the accelerator vacuum system, the Bremsstrahlung target and the isotope-production target, reducing remote handling problems. The electron beam can be scanned over a large target area to reduce the power density on both the Bremsstrahlung and isotope-production targets. These features address one of the most pressing technological challenges of a high-power RIB facility, namely the production of high yields of neutron-rich ions with reasonable power density in the target. The cost of an electron linac of the required specifications, including the facility shielding, is significantly less than the cost of any other primary-beam accelerator that could produce a comparable fission yield. A high-power electron linac could also be used with a multifoil helium-jet target. A large number of thin uranium foils could be irradiated with the scanned Bremsstrahlung beam and the fission fragments captured in aerosol-loaded helium and transported to an ion source that is well removed from the intense radiation fields of the primary target. The fission yield would be less than 1% of that available from a thick target, but this approach might be the easiest technical solution to obtain useable yields with manageable radiation-safety problems.

Diamond, William T.

1999-08-01

37

Reversible photodeposition and dissolution of metal ions  

DOEpatents

A cyclic photocatalytic process for treating waste water containing metal and organic contaminants. In one embodiment of the method, metal ions are photoreduced onto the photocatalyst and the metal concentrated by resolubilization in a smaller volume. In another embodiment of the method, contaminant organics are first oxidized, then metal ions removed by photoreductive deposition. The present invention allows the photocatalyst to be recycled until nearly complete removal of metal ions and organic contaminants is achieved.

Foster, Nancy S. (Boulder, CO); Koval, Carl A. (Golden, CO); Noble, Richard D. (Boulder, CO)

1994-01-01

38

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

39

Metallic ions in the equatorial ionosphere  

NASA Technical Reports Server (NTRS)

Four positive ion composition measurements of the equatorial E region made at Thumba, India, are presented. During the day, the major ions between 90 and 125 km are NO(+) and O2(+). A metallic ion layer centered at 92 km is observed, and found to contain Mg(+), Fe(+), Ca(+), K(+), Al(+), and Na(+) ions. The layer is explained in terms of a similarly shaped latitude distribution of neutral atoms which are photoionized and charge-exchanged with NO(+) and O2(+). Three body reactions form molecular metallic ions which are rapidly lost by dissociative ion-electron recombination. Nighttime observations show downward drifting of the metallic ion layer caused by equatorial dynamo effects. These ions react and form neutral metals which exchange charges with NO(+) and O2(+) to produce an observed depletion of those ions within the metallic ion region.

Aikin, A. C.; Goldberg, R. A.

1972-01-01

40

Pure radioactive Ga ion beams provided by new laser ion source for nuclear research at ORNL  

E-print Network

Pure radioactive Ga ion beams provided by new laser ion source for nuclear research at ORNL pure beams of radioactive nuclei far from stability. · Beams of neutron-rich Ga isotopes were delivered and intensity. · The -decay of the very exotic isotope 86Ga, delivered to LeRIBSS at the rate of several ions

41

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

SciTech Connect

SPIRAL2 is the new project under construction at GANIL to produce radioactive ion beams and in particular neutron rich ion beams. For the past 10 yr SPIRAL1 at GANIL has been delivering accelerated radioactive ion beams of gases. Both facilities now need to extend the range of radioactive ion beams produced to condensable elements. For that purpose, a resonant ionization laser ion source, funded by the French Research National Agency, is under development at GANIL, in collaboration with IPN Orsay, University of Mainz (Germany) and TRIUMF, Vancouver (Canada). A description of this project called GISELE (GANIL Ion Source using Electron Laser Excitation) is presented.

Lecesne, N.; Alves-Conde, R.; De Oliveira, F.; Dubois, M.; Flambard, J. L.; Franberg, H.; Jardin, P.; Leroy, R.; Pacquet, J. Y.; Pichard, A.; Saint-Laurent, M. G. [GANIL, BP 55027, 14076 Caen Cedex 5 (France); Coterreau, E.; Le Blanc, F.; Olivier, A. [IPN Orsay, BP 1-91406 Orsay (France); Gottwald, T.; Mattolat, C.; Wendt, K. [Johannes Gutenberg-Universitaet Mainz, Staudinger Weg 7, 55099 Mainz (Germany); Lassen, J. [TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3 (Canada); Rothe, S. [Department of Engineering, CERN, CH-1211 Geneva 23 (Switzerland)

2010-02-15

42

Status report on the Holifield Radioactive Ion Beam Project  

SciTech Connect

In July 1992, a project was started to reconfigure the Holifield Heavy Ion Research Facility (HHIRF) to form the Holifield Radioactive Ion Beam Facility (HRIBF). This ORNL project to produce medium-intensity, proton-rich, radioactive ion beams (RIBS) for astrophysics, nuclear physics, and applied research was first described to the SNEAP community at Chalk River in 1992. To briefly review, radioactive ions will be produced by light ion beams from the Oak Ridge Isochronous Cyclotron (ORIC) striking a target in an Isotope Separator On-Line (ISOL)-type target-ion source assembly. The radioactive ions will be converted to negative ions either directly in the ion source or by charge exchange following positive ionization. After acceleration to approximately 300 keV, these ions will be injected into the tandem accelerator for acceleration to higher energies. Successful production and acceleration of RIBs requires changes in the existing accelerators, development of the target-ion source, and construction of a new high-voltage injector and new injection beam line for the tandem accelerator. A floor plan of the facility as it should be when the project is finished is given. Progress has been made in a areas and will be detailed starting with the cyclotron.

Meigs, M.J.; Alton, G.D.; Auble, R.L. [and others

1994-12-31

43

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 138Xe 20+, 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.

Osa, Akihiko; TRIAC Collaboration

44

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

NASA Astrophysics Data System (ADS)

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 ?-decay properties of neutron-rich rare isotopes involved in the 3rd peak in the r-process element abundance.

Jeong, S. C.

2010-04-01

45

Ion-Exchange Characteristics of a Layered Metal Sulfide for Removal of Sr From Aqueous Solutions  

Microsoft Academic Search

Strontium-90 (Sr) is the most abundant radionuclide in radioactive wastes, and is typically isolated by treatment with an inorganic ion-exchange material. Most inorganic ion-exchange materials contain oxygen. The ion-exchange chemistry of layered metal sulfides is relatively poorly explored compared with that of oxide ion-exchange materials. Here, a layered metal sulfide (UCR-28), constructed from [ZnGe3S9(H2O)] supertetrahedral clusters, was prepared under hydrothermal

Xingliang Li; Bijun Liu; Yuan Jian; Wenbin Zhong; Wanjun Mu; Jiaheng He; Zongping Ma; Guoping Liu; Shunzhong Luo

2012-01-01

46

METHOD OF SEPARATING RARE EARTH METAL IONS  

Microsoft Academic Search

A method for separating rare earth metal ions by cation exchange is ; given. The method comprises sorbing the metal ions on the hydrogen form of a ; sulfonic acid type cation exchange resin, eluting the metals from the resin with ; a 0.01 to 0.1 M aqueous solution of an alkali salt of diethylenetriamine ; pentaacetic acid, and collecting

1962-01-01

47

Radioactive materials in recycled metals--an update.  

PubMed

In April 1995, Health Physics published a review paper titled "Radioactive Materials in Recycled Metals." At that time, 35 accidental meltings of radioactive sources in metal mills were reported, including 22 in the U.S., along with 293 other events in the U.S. where radioactive material was found in metals for recycling. Since that date, there have been additional accidental meltings of radioactive sources in metal mills both in the U.S. and elsewhere. There also was an incident in Texas that involved stolen radioactive devices, which resulted in exposures of members of the general public. Also, the U.S. Nuclear Regulatory Commission took steps to address the underlying problem of inadequate control and accountability of radioactive materials licensed by the Nuclear Regulatory Commission. The Steel Manufacturers Association made available data collected by its members beginning in 1994 that expanded the database for radioactive materials found by the metal recycling industry in recycled metal scrap to over 2,300 reports as of 30 June 1997. PMID:9482594

Lubenau, J O; Yusko, J G

1998-03-01

48

ISOL science at the Holifield Radioactive Ion Beam Facility  

SciTech Connect

The Holi eld Radioactive Ion Beam Facility, located in Oak Ridge, Tennessee, is operated as a National User Facility for the U.S. Department of Energy, producing high quality ISOL beams of short-lived, radioactive nuclei for studies of exotic nuclei, astrophysics research, and various societal applications. The primary driver, the Oak Ridge Isochronous Cyclotron, produces rare isotopes by bombarding highly refractory targets with light ions. The radioactive isotopes are ionized, formed into a beam, mass selected, injected into the 25-MV Tandem, accelerated, and used in experiments. This article reviews HRIBF and its science.

Beene, James R [ORNL; Bardayan, Daniel W [ORNL; Galindo-Uribarri, Alfredo {nmn} [ORNL; Gross, Carl J [ORNL; Jones, K. L. [University of Tennessee, Knoxville (UTK); Liang, J Felix [ORNL; Nazarewicz, Witold [ORNL; Stracener, Daniel W [ORNL; Tatum, B Alan [ORNL; Varner Jr, Robert L [ORNL

2011-01-01

49

In-Trap Spectroscopy of Charge-Bred Radioactive Ions  

NASA Astrophysics Data System (ADS)

In this Letter, we introduce the concept of in-trap nuclear decay spectroscopy of highly charged radioactive ions and describe its successful application as a novel spectroscopic tool. This is demonstrated by a measurement of the decay properties of radioactive mass A=124 ions (here, In124 and Cs124) in the electron-beam ion trap of the TITAN facility at TRIUMF. By subjecting the trapped ions to an intense electron beam, the ions are charge bred to high charge states (i.e., equivalent to the removal of N-shell electrons), and an increase of storage times to the level of minutes without significant ion losses is achieved. The present technique opens the venue for precision spectroscopy of low branching ratios and is being developed in the context of measuring electron-capture branching ratios needed for determining the nuclear ground-state properties of the intermediate odd-odd nuclei in double-beta (??) decay.

Lennarz, A.; Grossheim, A.; Leach, K. G.; Alanssari, M.; Brunner, T.; Chaudhuri, A.; Chowdhury, U.; Crespo López-Urrutia, J. R.; Gallant, A. T.; Holl, M.; Kwiatkowski, A. A.; Lassen, J.; Macdonald, T. D.; Schultz, B. E.; Seeraji, S.; Simon, M. C.; Andreoiu, C.; Dilling, J.; Frekers, D.

2014-08-01

50

Metal ion separations using electrically switched ion exchange  

Microsoft Academic Search

An electrochemical method for metal ion separations, called electrically switched ion exchange (ESIX), is described in this paper. In this method, direct oxidation and reduction of an electroactive film attached to an electrode surface is used to load and unload the film with alkali metal cations. The electroactive films under investigation are nickel hexacyanoferrates, which are deposited on the surface

M. A. Lilga; R. J. Orth; J. P. H. Sukamto; S. M. Haight; D. T. Schwartz

1997-01-01

51

Versatile high current metal ion implantation facility  

SciTech Connect

A metal ion implantation facility has been developed with which high current beams of practically all the solid metals of the periodic table can be produced. A multi-cathode, broad beam, metal vapor vacuum arc ion source is used to produce repetitively pulsed metal ion beams at an extraction voltage of up to 100 kV, corresponding to an ion energy of up to several hundred keV because of the ion-charge state multiplicity, and with a beam current of up to several amperes peak pulsed and several tens of mA time averaged delivered onto a downstream target. Implantation is done in a broad-beam mode, with a direct line-of-sight from ion source to target. Here we summarize some of the features of the ion source and the implantation facility that has been built up around it. 28 refs., 5 figs.

Brown, I.G.; Dickinson, M.R.; Galvin, J.E.; Godechot, X.; MacGill, R.A.

1991-06-01

52

THE METABOLISM OF TRACE METAL IONS  

Microsoft Academic Search

Several pathological connitions in man are characterized by the ; accumulation of large amounts of various trace metal ions, Prior studies ahve ; been directed toward the nutritional aspects of the essential metals. their role ; in enzyme systems, and their interaction with isolated protein frations. Little ; attention has been focused on the mechanisms by which these ions move

Saltman

1958-01-01

53

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

54

Pseudo ribbon metal ion beam sourcea)  

NASA Astrophysics Data System (ADS)

The paper describes high broad metal ion source based on dc macroparticle filtered vacuum arc plasma generation with the dc ion-beam extraction. The possibility of formation of pseudo ribbon beam of metal ions with the parameters: ion beam length 0.6 m, ion current up to 0.2 A, accelerating voltage 40 kV, and ion energy up to 160 kV has been demonstrated. The pseudo ribbon ion beam is formed from dc vacuum arc plasma. The results of investigation of the vacuum arc evaporator ion-emission properties are presented. The influence of magnetic field strength near the cathode surface on the arc spot movement and ion-emission properties of vacuum-arc discharge for different cathode materials are determined. It was shown that vacuum-arc discharge stability can be reached when the magnetic field strength ranges from 40 to 70 G on the cathode surface.

Stepanov, Igor B.; Ryabchikov, Alexander I.; Sivin, Denis O.; Verigin, Dan A.

2014-02-01

55

Pseudo ribbon metal ion beam source.  

PubMed

The paper describes high broad metal ion source based on dc macroparticle filtered vacuum arc plasma generation with the dc ion-beam extraction. The possibility of formation of pseudo ribbon beam of metal ions with the parameters: ion beam length 0.6 m, ion current up to 0.2 A, accelerating voltage 40 kV, and ion energy up to 160 kV has been demonstrated. The pseudo ribbon ion beam is formed from dc vacuum arc plasma. The results of investigation of the vacuum arc evaporator ion-emission properties are presented. The influence of magnetic field strength near the cathode surface on the arc spot movement and ion-emission properties of vacuum-arc discharge for different cathode materials are determined. It was shown that vacuum-arc discharge stability can be reached when the magnetic field strength ranges from 40 to 70 G on the cathode surface. PMID:24593634

Stepanov, Igor B; Ryabchikov, Alexander I; Sivin, Denis O; Verigin, Dan A

2014-02-01

56

Managing the disposition of potentially radioactive scrap metal.  

PubMed

In 2002, the National Council on Radiation Protection and Measurements (NCRP) issued Report No. 141, Managing Potentially Radioactive Scrap Metal. The report evaluates management policy and related issues regarding scrap metal generated in regulated facilities that have been under radiological control or have radiological concerns. It has been estimated that more than 9 million metric tons of scrap metal of all types that have been associated with the production or use of radioactive materials will be generated during the coming decades at various facilities across the United States. Currently, disposition of such metal has encountered particular obstacles, primarily because of the lack of a consistent disposition policy, systematic regulatory provisions, and, above all, public understanding. Without clarity in the regulatory passage, much of the scrap metal, including metal that has not been contaminated, could be mischaracterized as low-level radioactive waste, resulting in a costly disposition operation. NCRP Report No. 141 identifies this general category of metal as "potentially radioactive scrap metal" (PRSM) and discusses the viable disposition options for facilitating its management. Because much of the PRSM has been found to contain very low residual radioactivity or even none at all, one consideration is to release such metal outside of the radiological control framework. This would require the development and implementation of a set of strict release standards in the United States that would necessarily be risk-based and supported by a comprehensive management scheme. Developing a policy of this kind, however, would entail the resolution of many issues, not the least of which would be public acceptance, including that of the metal industry, of the possible recycling of PRSM in the general commerce. PMID:17033456

Chen, S Y

2006-11-01

57

The Production and Acceleration of Radioactive Ion Beams at the HRIBF  

SciTech Connect

The Holifield Radioactive Ion Beam Facility (HRIBF) includes a cyclotron (ORIC) which provides high-intensity light-ions for producing radioactive atoms, and a 25 MV tandem electrostatic accelerator which is used to accelerate the radioactive-ions for nuclear structure and nuclear astrophysics research. Ion sources and targets suitable for the production of various radioactive ion beams (RIBs) have been developed. Operational experiences, problem areas, and plans for future beam development are discussed.

Auble, R.L.

1998-11-04

58

Design of high-power ISOL targets for radioactive ion beam generation  

Microsoft Academic Search

In this report, we provide lists of refractory oxides, carbides and refractory metals suitable for use as targets for producing short-lived, proton-rich isotopes of elements (He through Pu) and neutron-rich isotopes of elements (As through Dy) for potential use at high-energy, ISOL-based radioactive ion beam facilities. Complex structure, highly permeable C matrices are described for coating with optimum thicknesses of

Y. Zhang; G. D. Alton

2004-01-01

59

Fusion Induced by Radioactive Ion Beams  

E-print Network

The use of radioactive beams opens a new frontier for fusion studies. The coupling to the continuum can be explored with very loosely bound nuclei. Experiments were performed with beams of nuclei at or near the proton and neutron drip-lines to measure fusion and associated reactions in the vicinity of the Coulomb barrier. In addition, the fusion yield is predicted to be enhanced in reactions involving very neutron-rich unstable nuclei. Experimental measurements were carried out to investigate if it is feasible to use such beams to produce new heavy elements. The current status of these experimental activities is given in this review.

J. F. Liang; C. Signorini

2005-04-26

60

?-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

2013-03-01

61

?-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

62

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

63

Ion sources for initial use 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 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. A 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 HRIBF 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. Prototype plasma-sputter negative ion sources and negative surface-ionization sources are also under design consideration for generating negative 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.

1993-12-31

64

Scrap metal management issues associated with naturally occurring radioactive material  

SciTech Connect

Certain industrial processes sometimes generate waste by-products that contain naturally occurring radioactive material (NORM) at elevated concentrations. Some industries, including the water treatment, geothermal energy, and petroleum industries, generate scrap metal that may be contaminated with NORM wastes. Of these three industries, the petroleum industry probably generates the largest quantity of NORM-contaminated equipment, conservatively estimated at 170,000 tons per year. Equipment may become contaminated when NORM-containing scale or sludge accumulates inside water-handling equipment. The primary radionuclides of concern in these NORM wastes are radium-226 and radium-228. NORM-contaminated equipment generated by the petroleum industry currently is managed several ways. Some equipment is routinely decontaminated for reuse; other equipment becomes scrap metal and may be disposed of by burial at a licensed landfill, encapsulation inside the wellbore of an abandoned well, or shipment overseas for smelting. In view of the increased regulatory activities addressing NORM, the economic burden of managing NORM-contaminated wastes, including radioactive scrap metal, is likely to continue to grow. Efforts to develop a cost-effective strategy for managing radioactive scrap metal should focus on identifying the least expensive disposition options that provide adequate protection of human health and the environment. Specifically, efforts should focus on better characterizing the quantity of radioactive scrap available for recycle or reuse, the radioactivity concentration levels, and the potential risks associated with different disposal options.

Smith, K.P.; Blunt, D.L.

1995-08-01

65

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

66

Charge breeding of radioactive ions with EBIS and EBIT  

NASA Astrophysics Data System (ADS)

A charge state breeder, which transforms externally injected singly charged ions to a higher charge state q+, is an important tool which has applications within atomic, nuclear and even particle physics. The charge breeding concept of radioactive ions has already been demonstrated at REX-ISOLDE/CERN with the use of an Electron beam Ion Source (EBIS) and at several facilities employing Electron Resonance Cyclotron Ion Sources (ECRIS). As will be demonstrated in this paper, EBIS and Electron Beam Ion Traps (EBIT), are well suited for the task as they are capable of delivering clean, highly charged beams within a short transformation time. The increasing demand for highly charged ions of all kind of elements and isotopes, stable and radioactive, to be used for low-energy experiments such as TITAN at TRIUMF and MATS at FAIR, but also for post-acceleration to higher energies, is now pushing the development of the breeders. The next challenge will be to satisfy the needs, for example space-charge capacity, of the second generation radioactive beam facilities presently under construction or in the design stage, such as the MSU re-accelerator (ReA3), SPIRAL2, SPES and later on EURISOL. Radioactive trap facilities will also require high performance breeders geared towards rapid breeding times. The requirements and the critical issues of the breeding concept will be discussed and a review of the different facilities, operational and planned, will be given. The paper does furthermore feature a summary of the extensive breeding experience gained under operational conditions at REX-ISOLDE, including results from dedicated beam cleaning tests, isotope production using in-trap decay, high-current and continuous ion injection into the breeder, and closed-shell breeding.

Wenander, F.

2010-10-01

67

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

68

ION EXCHANGE SOFTENING: EFFECTS ON METAL CONCENTRATIONS  

EPA Science Inventory

A corrosion control pipe loop study to evaluate the effect of ion exchange water softening on metal leaching from household plumbing materials was conducted on two different water qualities having different pH's and hardness levels. The results showed that removing hardness ions ...

69

Upgraded vacuum arc ion source for metal ion implantationa)  

NASA Astrophysics Data System (ADS)

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.; Brown, I. G.

2012-02-01

70

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

71

Bioavailability of Metal Ions and Evolutionary Adaptation  

PubMed Central

The evolution of life on earth has been a long process that began nearly 3.5 × 109 years ago. In their initial moments, evolution was mainly influenced by anaerobic environments; with the rise of O2 and the corresponding change in bioavailability of metal ions, new mechanisms of survival were created. Here we review the relationships between ancient atmospheric conditions, metal ion bioavailability and adaptation of metals homeostasis during early evolution. A general picture linking geochemistry, biochemistry and homeostasis is supported by the reviewed literature and is further illustrated in this report using simple database searches. PMID:25371266

Hong Enriquez, Rolando P.; Do, Trang N.

2012-01-01

72

Radioactive ion beam production challenges at the Holifield Heavy Ion Research Facility  

SciTech Connect

The radioactive ion beam (RIB) project at the Holifield Heavy Ion Research Facility (HHIRF) will provide for reconfiguration of the HHIRF accelerator system to enable provision of low-intensity RIBs for nuclear and astrophysics research. As we have progressed with the design of the reconfiguration, we have encountered several challenges that were not immediately obvious when first contemplating the project. The challenges do not seem insurmountable but should keep life interesting for those of us doing the work. A brief review of the project will allow a better understanding of the challenges in RIB production. Radioactive ion beams will be produced with the Isotope Separator On-Line (ISOL) postacceleration technique. In particular, radioactive atoms will be produced by reactions in the thick stopping target of an ISOL-type target-ion source assembly using intense beams from the Oak Ridge Isochronous Cyclotron equipped with a light-ion internal source. This ISOL target-ion source assembly will be mounted on a high-voltage platform with a mass separator. The target ion source will operate at potentials up to 50 kV with respect to the high voltage platform. The radioactive atoms produced by nuclear reactions in the target diffuse to the surface of the heated target material, desorb from this surface, and effuse through a heated transfer tube into an ion source where ionization and extraction take place. Two types of ion sources will be initially considered. A Forced Electron Beam Induced Arc Discharge source, similar to those used by the ISOLDE facility at CERN and by the UNISOR facility at ORNL, will be built to produce positive ions. These positive ions will be focused through an alkali vapor charge-exchange canal to produce negative ions for tandem injection. In addition, a direct negative surface ionization addition or modification to the above source will be built and investigated.

Meigs, M.J.; Alton, G.D.; Dowling, D.T.; Haynes, D.L.; Jones, C.M.; Juras, R.C.; Lane, S.N.; Mills, G.D.; Mosko, S.W.; Olsen, D.K.; Tatum, B.A.

1992-12-31

73

Radioactive ion beam production challenges at the Holifield Heavy Ion Research Facility  

SciTech Connect

The radioactive ion beam (RIB) project at the Holifield Heavy Ion Research Facility (HHIRF) will provide for reconfiguration of the HHIRF accelerator system to enable provision of low-intensity RIBs for nuclear and astrophysics research. As we have progressed with the design of the reconfiguration, we have encountered several challenges that were not immediately obvious when first contemplating the project. The challenges do not seem insurmountable but should keep life interesting for those of us doing the work. A brief review of the project will allow a better understanding of the challenges in RIB production. Radioactive ion beams will be produced with the Isotope Separator On-Line (ISOL) postacceleration technique. In particular, radioactive atoms will be produced by reactions in the thick stopping target of an ISOL-type target-ion source assembly using intense beams from the Oak Ridge Isochronous Cyclotron equipped with a light-ion internal source. This ISOL target-ion source assembly will be mounted on a high-voltage platform with a mass separator. The target ion source will operate at potentials up to 50 kV with respect to the high voltage platform. The radioactive atoms produced by nuclear reactions in the target diffuse to the surface of the heated target material, desorb from this surface, and effuse through a heated transfer tube into an ion source where ionization and extraction take place. Two types of ion sources will be initially considered. A Forced Electron Beam Induced Arc Discharge source, similar to those used by the ISOLDE facility at CERN and by the UNISOR facility at ORNL, will be built to produce positive ions. These positive ions will be focused through an alkali vapor charge-exchange canal to produce negative ions for tandem injection. In addition, a direct negative surface ionization addition or modification to the above source will be built and investigated.

Meigs, M.J.; Alton, G.D.; Dowling, D.T.; Haynes, D.L.; Jones, C.M.; Juras, R.C.; Lane, S.N.; Mills, G.D.; Mosko, S.W.; Olsen, D.K.; Tatum, B.A.

1992-01-01

74

Nuclear astrophysics at the Holifield Radioactive Ion Beam Facility  

SciTech Connect

The potential for understanding spectacular stellar explosions such as novae, supernovae, and X-ray bursts will be greatly enhanced by the availability of the low-energy, high-intensity, accelerated beams of proton-rich radioactive nuclei currently being developed at the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory. These beams will be utilized in absolute cross section measurements of crucial (p, {gamma}) capture reactions in efforts to resolve the substantial qualitative uncertainties in current models of explosive stellar hydrogen burning outbursts. Details of the nuclear astrophysics research program with the unique HRIBF radioactive beams and a dedicated experimental endstation--centered on the Daresbury Recoil Separator--will be presented.

Smith, M.S.

1994-12-31

75

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

76

Metal vapor vacuum arc ion sources  

SciTech Connect

We have developed a family of metal vapor vacuum are (MEVVA) high current metal ion sources. The sources were initially developed for the production of high current beams of metal ions for heavy ion synchrotron injection for basic nuclear physics research; more recently they have also been used for metal ion implantation. A number of different embodiments of the source have been developed for these specific applications. Presently the sources operate in a pulsed mode, with pulse width of order 1 ms and repetition rate up to 100 pps. Beam extraction voltage is up to 100 kV, and since the ions produced in the vacuum arc plasma are in general multiply ionized the ion energy is up to several hundred keV. Beam current is up to several Amperes peak and around 10 mA time averaged delivered onto target. Nearly all of the solid metals of the Periodic Table have been use to produce beam. A number of novel features have been incorporated into the sources, including multiple cathodes and the ability to switch between up to 18 separate cathode materials simply and quickly, and a broad beam source version as well as miniature versions. here we review the source designs and their performance. 45 refs., 7 figs.

Brown, I.G.; Dickinson, M.R.; Galvin, J.E.; Godechot, X.; MacGill, R.A.

1990-06-01

77

Radioactive ion beam acceleration at MAFF  

NASA Astrophysics Data System (ADS)

In April 2003, the German safety commission has given the final approval for the oper- ation of the high flux reactor FRM-II. This is an important step towards the development and installation of the Munich accelerator for fission fragments (MAFF), which will deliver highest intensities of neutron rich fission fragments. The acceleration chain of MAFF [1] consists of a charge breeder, which will deliver the ions with a mass to charge ratio of A/q ? 6.3 irrespective of the mass range, and with a repetition rate of maximum 50 Hz. The LINAC operating at 10% duty cycle is composed of a 101.28 IH-RFQ, which will boost up the energy from 2.5 up to 300 keV/u, three IH-tanks that will deliver an energy of 5.4 MeV/u and 2 seven gap IH-resonators that are used to vary the final energy up to a maximum of 5.9 MeV/u. Currently beam dynamics revisions are in progress especially in the low energy section, since the experimental program has requested specific time structures of the beam for TOF experiments. The status of the beam dynamics studies as well as the status of the single components of the accelerator will be presented in this paper.

Pasini, M.; Kester, O.; Habs, D.; Groß, M.; Sieber, T.; Maier, H. J.; Assmann, W.; Krüken, R.; Faestermann, T.; Schempp, A.; Ratzinger, U.; Safvan, C. P.

2004-12-01

78

First online production of radioactive ion beams at VECC  

NASA Astrophysics Data System (ADS)

Radioactive ion beams (RIB) have been recently accelerated for the first time at the VECC-RIB facility. Beams of 14O (71 s), 42K (12.4 h), 43K (22 h) and 41Ar (1.8 h) have been produced by bombarding 1 atm nitrogen and argon gas targets with 1 micro-ampere proton and alpha particle beams from the K130 cyclotron. Radioactive atoms were transported 15 m away to the ECR ion-source using a gas-jet transport system. Typical measured intensity of RIB at the separator focal plane is few times 103 pps. About 3300 pps of 1.4 MeV 14O was measured after acceleration through a 3.4 m long RFQ linac. The details of the gas-jet coupled ECR and RIB production experiments are presented.

Naik, Vaishali; Chakrabarti, Alok; Bhattacharjee, Mahuwa; Karmakar, Prasanta; Bhattacharjee, Sampa; Bandyopadhyay, Arup; Dechoudhury, Siddhartha; Kumar, Dodi Lavanya; Mondal, Manas; Pandey, H. K.; Mandi, T. K.; Dutta, D. P.; Roy, Tapatee Kundu; Bhowmik, Debasis; Sanyal, Dirtha; Ray, Ayan; Sabir Ali, Md.; Srivastava, S. C. L.; Nabhiraj, P. Y.

2013-12-01

79

The SPES radioactive ion beam project of INFN  

NASA Astrophysics Data System (ADS)

The SPES Radioactive Ion Beam facility at INFN-LNL is presently in the construction phase. The facility is based on the Isol (Isotope separation on-line) method with an UCx Direct Target able to sustain a power of 10 kW. The primary proton beam is provided by a high current Cyclotron accelerator with energy of 35-70 MeV and a beam current of 0.20.5 mA. Neutron-rich radioactive ions are produced by proton induced Uranium fission at an expected fission rate of the order of 1013 fissions per second. After ionization and selection the exotic isotopes are re-accelerated by the ALPI superconducting Linac at energies of 10A MeV for masses in the region A = 130 amu. The expected secondary beam rates are of the order of 107 - 109 pps. Aim of the SPES project is to provide a facility for high intensity radioactive ion beams for nuclear physics research as well as to develop an interdisciplinary research center based on the cyclotron proton beam.

de Angelis, Giacomo; Spes Collaboration; Prete, G.; Andrighetto, A.; Manzolaro, M.; Corradetti, S.; Scarpa, D.; Rossignoli, M.; Monetti, A.; Lollo, M.; Calderolla, M.; Vasquez, J.; Zafiropoulos, D.; Sarchiapone, L.; Benini, D.; Favaron, P.; Rigato, M.; Pegoraro, R.; Maniero, D.; Calabretta, L.; Comunian, M.; Maggiore, M.; Lombardi, A.; Piazza, L.; Porcellato, A. M.; Roncolato, C.; Bisoffi, G.; Pisent, A.; Galatà, A.; Giacchini, M.; Bassato, G.; Canella, S.; Gramegna, F.; Valiente, J.; Bermudez, J.; Mastinu, P. F.; Esposito, J.; Wyss, J.; Russo, A.; Zanella, S.

2014-07-01

80

Holifield!Radioactive!Ion!Beam!Facility! Cyclotron!Driver!White!Paper!  

E-print Network

Holifield!Radioactive!Ion!Beam!Facility! Cyclotron!Driver!White!Paper! ! ! ! ! prepared!in!response!! to!a!recommendation!from!the! !! Annual!Science!and!Technology!Review!! of!the!! Holifield!Radioactive!provides!preliminary!details!of!a!proposed!hadron!driver!accelerator! upgrade!(HDU)!to!the!Holifield!Radioactive!Ion!Beam!Facility!(HRIBF),!a!national!user! facility! for

81

[Development of trace metal ion analysis].  

PubMed

Analyses of trace biologically essential or toxic ionic compounds found in the environment are very important. However, the lack of sensitivity and interference caused by coexisting components are often serious problems. To determine trace levels of metal ions without the above problems, new preconcentration and analytical methods have been developed. Firstly, three methods for the selective preconcentration of metal ions are shown below: 1) 3-Chloropyridazine-6-carbohydrazide was immobilized on glass beads supports to be used as a column packing material. Multi-metal ions were concentrated on the column and eluted selectively with several buffers and hydrochloric acid. The eluate was analyzed off-line by flame atomized-atomic absorption spectrometry (AAS). This method was able to determine sub-ppb levels of cupper- and cadmium-ions in environmental samples. 2) Salicylideneamino-2-thiophenol was immobilized on the supports. Aluminum ion was concentrated selectively on the column and eluted with nitric acid. The eluate was analyzed off-line by flameless-AAS or on-line by flow injection analysis using pyrocatechol violet for a post-column colorimetric reagent. These methods were able to determine ppb-ppt levels of aluminium in environmental samples and were suitable for its state-analysis. 3) Bathocuproinesulfonic acid was immobilized on the supports. Copper ion was concentrated selectively on the column and eluted with nitric acid. The eluate was analyzed on-line by flow injection analysis using bathocuproinesulfonic acid. This method was able to determine sub-ppb levels of copper in environmental samples. On the other hand, to analyze simultaneously trace metal ions and anions, capillary electrophoresis was performed using ethylenediaminetetraacetic acid as an electrolyte component. Simultaneous determination of several ions in mineral waters was achieved by the system. PMID:11019646

Kobayashi, J

2000-09-01

82

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

83

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

84

Control system for the Holifield Radioactive Ion Beam Facility  

SciTech Connect

A new accelerator control system is being implemented as part of the development of the Holifield Radioactive Ion Beam Facility (HRIBF), a first generation radioactive ion beam (RIB) facility. The pre- existing accelerator control systems are based on 1970`s technology and addition or alteration of controls is cumbersome and costly. A new, unified control system for the cyclotron and tandem accelerators, the RIB injector, ion sources, and accelerator beam lines is based on a commercial product from Vista Control Systems, Inc. Several other accelerator facilities, as well as numerous industrial sites, are now using this system. The control system is distributed over a number of computers which communicate over Ethernet and is easily extensible. Presently, implementation at the HRIBF is based on VAX/VMS, VAX/ELN, VME, and Allen-Bradley PLC5 programmable logic controller architectures. Expansion to include UNIX platforms and CAMAC hardware support is planned. Operator interface is via X- terminals. The system has proven to be quite powerful, yet is has been easy to implement with a small staff. A Vista users group has resulted in shared software to implement specific controls. This paper details present system features and future implementations at the HRIBF.

Tatum, B.A.; Juras, R.C.; Meigs, M.J.

1995-12-31

85

Metal vapor vacuum arc ion source  

SciTech Connect

A high-current ion source is described in which a metal vapor vacuum arc is used to create the plasma from which the ion beam is extracted. An ion beam current of up to about 1 A has been measured at an extraction voltage of 25 kV for a range of metallic species spanning the periodic table from lithium to uranium. Multiply ionized charge states are seen up to as high as Q = 6+ in the case of uranium. In the metal vapor vacuum arc, regions of intense current concentration are formed at the cathode, and it is at these regions, the cathode spots, that the cathode material is vaporized and ionized to form a dense, quasi-neutral plasma which plumes away from the cathode surface. The plasma plume is caused to impinge upon a set of extractor grids, and the ion beam is extracted from the streaming metal plasma. A preliminary survey of the performance of the source has been made. We describe here the principle of operation of the source, the source design, and the results of those measurements that we have made to date.

Brown, I.G.; Galvin, J.E.; Gavin, B.F.; MacGill, R.A.

1986-06-01

86

Material Removes Heavy Metal Ions From Water  

NASA Technical Reports Server (NTRS)

New high capacity ion-exchange polymer material removes toxic metal cations from contaminated water. Offers several advantages. High sensitivities for such heavy metals as lead, cadmium, and copper and capable of reducing concentrations in aqueous solutions to parts-per-billion range. Removes cations even when calcium present. Material made into variety of forms, such as thin films, coatings, pellets, and fibers. As result, adapted to many applications to purify contaminated water, usually hard wherever found, whether in wastewater-treatment systems, lakes, ponds, industrial plants, or homes. Another important feature that adsorbed metals easily reclaimed by either destructive or nondestructive process. Other tests show ion-exchange polymer made inexpensively; easy to use; strong, flexible, not easily torn; and chemically stable in storage, in aqueous solutions, and in acidic or basic solution.

Philipp, Warren H., Jr.; Street, Kenneth W.; Hill, Carol; Savino, Joseph M.

1995-01-01

87

A new chemical oscillator containing neither metal nor oxyhalogen ions  

Microsoft Academic Search

Essentially all known inorganic chemical oscillators1 contain a metal ion2-4 and\\/or an oxyhalogen ion, in particular, iodate ion3, bromate ion2,5 or chlorite ion6. We report here a new chemical oscillator that is based on sulphur chemistry and contains neither a metal ion nor an oxyhalogen ion. The oscillator does involve elemental oxygen, and in this way it may be related

Maria Burger; Richard J. Field

1984-01-01

88

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

89

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

90

Detection of Heavy Metal Ions in Drinking Water Using a  

E-print Network

Detection of Heavy Metal Ions in Drinking Water Using a High-Resolution Differential Surface, and clinical toxicology. A number of techniques have been developed over the years for heavy metal ion analysis-resolution differential surface plasmon resonance (SPR) sensor for heavy metal ion detection. The sensor surface

Chen, Wilfred

91

Application of ion implantation in metals and alloys  

Microsoft Academic Search

Ion implantation first became established as a precise method of introducing dopant elements into semiconductors. It is now appreciated that there may be equally important applications in metallic tools or components with the purpose of improving their resistance to wear, fatigue or corrosion. Nitrogen ions implanted into steels pin dislocations and thereby harden the metal. Some metallic ions such as

Dearnaley

1981-01-01

92

Assessment of recycling or disposal alternatives for radioactive scrap metal  

SciTech Connect

The US Department of Energy, Office of Environmental Restoration and Waste Management, Oak Ridge Programs Division, is participating with the Organization for Economic Cooperation and Development in providing analytical support for evaluation of management alternatives for radioactive scrap metals. For this purpose, Argonne National Laboratory is assessing environmental and societal implications of recycling and/or disposal process alternatives. This effort includes development of inventory estimates for contaminated metals; investigation of scrap metal market structure, processes, and trends; assessment of radiological and nonradiological effects of recycling; and investigation of social and political factors that are likely to either facilitate or constrain recycling opportunities. In addition, the option of scrap metal disposal is being assessed, especially with regard to the environmental and health impacts of replacing these metals if they are withdrawn from use. This paper focuses on the radiological risk assessment and dose estimate sensitivity analysis. A {open_quotes}tiered{close_quotes} 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 conservatism 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 [US Dept. of Energy, Oak Ridge, TN (United States); Nieves, L.A.; Chen, S.Y. [Argonne National Lab., IL (United States)

1993-11-01

93

Interplay of metal ions and urease  

PubMed Central

Summary Urease, the first enzyme to be crystallized, contains a dinuclear nickel metallocenter that catalyzes the decomposition of urea to produce ammonia, a reaction of great agricultural and medical importance. Several mechanisms of urease catalysis have been proposed on the basis of enzyme crystal structures, model complexes, and computational efforts, but the precise steps in catalysis and the requirement of nickel versus other metals remain unclear. Purified bacterial urease is partially activated via incubation with carbon dioxide plus nickel ions; however, in vitro activation also has been achieved with manganese and cobalt. In vivo activation of most ureases requires accessory proteins that function as nickel metallochaperones and GTP-dependent molecular chaperones or play other roles in the maturation process. In addition, some microorganisms control their levels of urease by metal ion-dependent regulatory mechanisms. PMID:20046957

Carter, Eric L.; Flugga, Nicholas; Boer, Jodi L.; Mulrooney, Scott B.; Hausinger, Robert P.

2009-01-01

94

Effects of ion irradiation in metallic glasses  

Microsoft Academic Search

Application of metallic glasses as structural materials has been limited by their poor ductility. To overcome brittle failure, nanocrystals are intentionally introduced to stabilize the glasses. In this study, we report on the application of ion irradiation to induce nanocrystalization in a Cu50Zr45Ti5 (CZT) alloy. Transmission electron microcopy, microindentation and nanoindentation have been used to characterize the CZT alloy irradiated

Jesse Carter; E. G. Fu; G. Bassiri; B. M. Dvorak; N. David Theodore; Guoqiang Xie; D. A. Lucca; Michael Martin; Mark Hollander; Xinghang Zhang; Lin Shao

2009-01-01

95

Spectroscopic investigations of fluoroquinolones metal ion complexes.  

PubMed

The complex formation reaction, between fluoroquinolones (FQ): ciprofloxacin (CPX), enoxacin (ENX), enrofloxacin (ENRX), lomefloxacin (LOMX), levofloxacin (LEVX), ofloxacin (OFX), norfloxacin (NFX), sparfloxacin (SPRX) and aluminum(III), iron(III), copper(II) and zinc(II) ions were investigated. The spectrophotometic titration method in a wide range of pH was utilized for estimation of complex formation equilibrium. The application of Bjerrum method allowed to estimate the complex equilibrium of analyzed species in the reaction mixture. The overall stability constants (logbeta(pqr)) of fluoroquinolones complexes with metal ions were calculated using HYPRERQUAD program. The most stable complexes FQ were created with iron(III) and aluminum(III) and than copper(II) and zinc(II) ions, respectively. The highest values of calculated logbeta(pqr) were obtained for the Me(FQ)3H3 species and the lowest for the Me(FQ)2OH forms. Furthermore, an additional studies have been performed. The effect of the polyvalent metal ions on the complex structure has been investigated. The IR and 1H, 13C and 19F NMR spectroscopy methods were used for the confirmation of the structure of the FQ-Me complex formations. The most significant shifts of signals of 1H NMR spectra of the fluoroquinolones and their complexes were found for the protons substituted in the positions 2, 5 and 8, whereas the 13C NMR spectra showed up the shifts changes for carbon atoms in positions 2, 3, 3a and 4. PMID:23923386

Urbaniak, Bartosz; Kokot, Zenon J

2013-01-01

96

Alkali metal ion templated transition metal formate framework materials: synthesis, crystal structures, ion migration, and magnetism.  

PubMed

Four transition metal formate coordination polymers with anionic frameworks, namely, Na[Mn(HCOO)3], K[Mn(HCOO)3], Na2[Cu3(HCOO)8], and K2[Cu5(HCOO)12], were synthesized using a mild solution chemistry approach. Multitemperature single-crystal (100-300 K) and powder X-ray diffraction studies of the compounds reveal structures of large diversity ranging from cubic chiral Na-Mn formate to triclinic Na-Cu formate. The structural variety is caused by the nature of the transition metals, the alkali metal ion templation, and the versatility of the formate group, which offers metal-metal coordination through three different O-C-O bridging modes (syn-syn, syn-anti, anti-anti) in addition to metal-metal bridging via a single oxygen atom. The two manganese(II) compounds contain mononuclear, octahedrally coordinated moieties, but the three-dimensional connectivity between the manganese octahedra is very different in the two structures. The two copper frameworks, in contrast, consist of binuclear and mononuclear moieties (Na-Cu formate) and trinuclear and mononuclear moieties (K-Cu formate), respectively. Procrystal electron density analysis of the compounds indicates one-dimensional K(+)-ion conductivity in K-Mn and K-Cu, and the nature of the proposed potassium ion migration is compared with results from similar analysis on known Na(+) and K(+) ion conductors. K-Mn and Na-Mn were tested as cathode materials, but this resulted in poor reversibility due to low conductivity or structural collapse. The magnetic properties of the compounds were studied by vibrating sample magnetometric measurements, and their thermal stabilities were determined by thermogravimetric analysis and differential thermal analysis. Despite structural differences, the metal formates that contain the same transition metal have similar magnetic properties and thermal decomposition pathways, that is, the nature of the transition metal controls the compound properties. PMID:25233266

Eikeland, Espen; Lock, Nina; Filsø, Mette; Stingaciu, Marian; Shen, Yanbin; Overgaard, Jacob; Iversen, Bo Brummerstedt

2014-10-01

97

Low-energy radioactive ion beam production of 22Mg  

NASA Astrophysics Data System (ADS)

The 22Mg nucleus plays an important role in nuclear astrophysics, specially in the 22Mg(?,p)25Al and proton capture 22Mg(p,?)23Al reactions. It is believed that 22Mg is a waiting point in the ?p-process of nucleosynthesis in novae. We proposed a direct measurement of the 22Mg+? resonance reaction in inverse kinematics using a radioactive ion (RI) beam. A 22Mg beam of 3.73 MeV/u was produced at CRIB (Center for Nuclear Study (CNS) low-energy RI Beam) facility of the University of Tokyo located at RIKEN (Japan) in 2011. In this paper we present the results about the production of the 22Mg beam used for the direct measurement of the scattering reaction 22Mg(?,?)22Mg, and the stellar reaction 22Mg(?,p)25Al in the energy region concerning an astrophysical temperature of T9=1-3 GK.

Duy, N. N.; Kubono, S.; Yamaguchi, H.; Kahl, D.; Wakabayashi, Y.; Teranishi, T.; Iwasa, N.; Kwon, Y. K.; Khiem, L. H.; Kim, Y. H.; Song, J. S.; Hu, J.; Ayyad, Y.

2013-09-01

98

The future radioactive ion beam research program at Oak Ridge  

SciTech Connect

Early in 1995, the ORNL Holifield Facility is scheduled to return to operation as a dedicated radioactive ion beam (RIB) facility. This enhanced capability will open up new possibilities for research on the structure of and phenomena occurring in proton-rich nuclei. Among the opportunities will be the creation of heavier N{approximately}Z nuclei, approaching {sup 100}Sn, and the study of exotic nuclear shapes, extensions of studies of the p-n interaction and super-allowed beta decay, and examination of nuclear structure near the proton drip line. In addition to new nuclear and atomic physics research opportunities, the beams from the Holifield RIB facility are expected to provide new capabilities for measurements important to nuclear astrophysics. To carry out this experimental program, various upgrades are planned to the existing experimental apparatus, and a new, third-generation, recoil-mass separator is being constructed.

Ball, J.B.

1993-11-01

99

ORNL developments in laser ion sources for radioactive ion beam production  

NASA Astrophysics Data System (ADS)

The development of a resonant ionization laser ion source (RILIS) for the production of isotopically pure radioactive ion beams is reported. The application of the laser ion source calls for high elemental selectivity, high efficiency, and fast release of short-lived isotopes. A hot-cavity ion source and three Ti:sapphire lasers pulsed at a 10 kHz rate are employed for the RILIS. The Ti:sapphire lasers have been upgraded with individual pump lasers to eliminate intracavity Pockels cells and output losses due to synchronization delays. The development of ionization schemes for a wide range of elements is important to the success of Ti:sapphire-laser-based RILIS. In off-line studies with stable isotopes, resonant ionization of 14 elements has been studied, leading to new ionization schemes for ten elements. The absolute ionization efficiency of the hot-cavity RILIS has been measured to range from 0.9 % to 40 % for different elements. The mechanisms for ion transportation and confinement in the hot-cavity ion source have been studied using the temporal profiles of the laser-ionized ions. The hot-cavity RILIS has provided beams of neutron-rich Ga isotopes for beta decay studies and enabled the first measurement of the beta decay of the exotic Ga.

Liu, Yuan

2014-06-01

100

A gas jet target for radioactive ion beam experiments  

SciTech Connect

New radioactive ion beam (RIB) facilities, like FRIB in the US or FAIR in Europe, will push further away from stability and enable the next generation of nuclear physics experiments. Thus, the need for improved RIB targets is more crucial than ever: developments in exotic beams should coincide with developments in targets for use with those beams, in order for nuclear physics to remain on the cutting edge. Of great importance to the future of RIB physics are scattering, transfer and capture reaction measurements of rare, exotic, and unstable nuclei on light targets such as hydrogen and helium. These measurements require targets that are dense, highly localized, and pure, and conventional targets often suffer too many drawbacks to allow for such experimental designs. Targets must also accommodate the use of large area, highly-segmented silicon detector arrays, high-efficiency gamma arrays, and novel heavy ion detectors to efficiently measure the reaction products. To address this issue, the Jet Experiments in Nuclear Structure and Astrophysics (JENSA) Collaboration led by the Colorado School of Mines (CSM) is in the process of designing, building and testing a supersonic gas jet target for use at existing and future RIB facilities. The gas jet target provides a high density and high purity of target nuclei within a tightly confined region, without the use of windows or backing materials. The design also enables the use of multiple state-of-the-art detection systems.

Chipps, K. A.; Greife, U.; Hager, U.; Sarazin, F. [Colorado School of Mines, Golden, CO (United States); Bardayan, D. W.; Pain, S. D.; Schmitt, K. T.; Smith, M. S. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Blackmon, J. C.; Linhardt, L. E. [Louisiana State University, Baton Rouge, LA (United States); Browne, J.; Kontos, A.; Meisel, Z.; Montes, F.; Schatz, H. [National Superconducting Cyclotron Laboratory/Michigan State University, East Lansing, MI (United States); Couder, M.; Robertson, D.; Wiescher, M. [University of Notre Dame, Notre Dame, IN (United States); Erikson, L. E. [Pacific Northwest National Laboratory, Richland, WA (United States); Lemut, A. [Lawrence Berkeley National Laboratory, Berkeley, CA (United States); and others

2013-04-19

101

High-spin nuclear structure studies with radioactive ion beams  

SciTech Connect

Two important developments in the sixties, namely the advent of heavy-ion accelerators and fabrication of Ge detectors, opened the way for the experimental studies of nuclear properties at high angular momentum. Addition of a new degree of freedom, namely spin, made it possible to observe such fascinating phenomena as occurrences and coexistence of a variety of novel shapes, rise, fall and occasionally rebirth of nuclear collectivity, and disappearance of pairing correlations. Today, with the promise of development of radioactive ion beams (RIB) and construction of the third-generation Ge-detection systems (GAMMASPHERE and EUROBALL), the authors are poised to explore new and equally fascinating phenomena that have been hitherto inaccessible. With the addition of yet another dimension, namely the isospin, they will be able to observe and verify predictions for exotic shapes as varied as rigid triaxiality, hyperdeformation and triaxial octupole shapes, or to investigate the T = 0 pairing correlations. In this paper, they shall review, separately for neutron-deficient and neutron-rich nuclei, these and a few other new high-spin physics opportunities that may be realized with RIB. Following this discussion, they shall present a list of the beam species, intensities and energies that are needed to fulfill these goals. The paper will conclude with a description of the experimental techniques and instrumentations that are required for these studies.

Baktash, C.

1992-12-31

102

Study of Nuclear Reactions with 11C and 15O Radioactive Ion Beams  

SciTech Connect

Nuclear reaction study with radioactive ion beams is one of the most exciting research topics in modern nuclear physics. The development of radioactive ion beams has allowed nuclear scientists and engineers to explore many unknown exotic nuclei far from the valley of nuclear stability, and to further our understanding of the evolution of the universe. The recently developed radioactive ion beam facility at the Lawrence Berkeley National Laboratory's 88-inch cyclotron is denoted as BEARS and provides {sup 11}C, {sup 14}O and {sup 15}O radioactive ion beams of high quality. These moderate to high intensity, proton-rich radioactive ion beams have been used to explore the properties of unstable nuclei such as {sup 12}N and {sup 15}F. In this work, the proton capture reaction on {sup 11}C has been evaluated via the indirect d({sup 11}C, {sup 12}N)n transfer reaction using the inverse kinematics method coupled with the Asymptotic Normalization Coefficient (ANC) theoretical approach. The total effective {sup 12}N {yields} {sup 11}C+p ANC is found to be (C{sub eff}{sup 12{sub N}}){sup 2} = 1.83 {+-} 0.27 fm{sup -1}. With the high {sup 11}C beam intensity available, our experiment showed excellent agreement with theoretical predictions and previous experimental studies. This study also indirectly confirmed that the {sup 11}C(p,{gamma}) reaction is a key step in producing CNO nuclei in supermassive low-metallicity stars, bypassing the slow triple alpha process. The newly developed {sup 15}O radioactive ion beam at BEARS was used to study the poorly known level widths of {sup 16}F via the p({sup 15}O,{sup 15}O)p reaction. Among the nuclei in the A=16, T=1 isobaric triad, many states in {sup 16}N and {sup 16}O have been well established, but less has been reported on {sup 16}F. Four states of {sup 16}F below 1 MeV have been identified experimentally: 0{sup -}, 1{sup -}, 2{sup -}, and 3{sup -} (E{sub x} = 0.0, 0.19, 0.42, and 0.72 MeV, respectively). Our study utilized R-matrix analysis and found that the 0- state has a level width of 23.1 {+-} 2.2 keV, and that the broader 1- state has a width of 91.1 {+-} 9.9 keV. The level width of the 2{sup -} state is found to be 3.3 {+-} 0.6 keV which is much narrower than the compiled value of 40 {+-} 30 keV, while a width of 14.1 {+-} 1.7 keV for the 3{sup -} state is in good agreement with the reported value (< 15 keV). These experimental level widths of all four levels are also in accordance with theoretical predictions using single particle shell model calculation.

Lee, Dongwon

2007-05-14

103

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

PubMed Central

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.

2012-01-01

104

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

105

Semicondutor quantum dots-based metal ion probes  

NASA Astrophysics Data System (ADS)

Semiconductor quantum dots (QDs) exhibit unique optical and photophysical properties that offer significant advantages over organic dyes as optical labels for chemo/bio-sensing. This review addresses the methods for metal ion detection with QDs, including photoluminescent, electrochemiluminescent, photoelectrochemical, and electrochemical approaches. The main mechanisms of direct interaction between QDs and metal ions which lead to photoluminescence being either off or on, are discussed in detail. These direct interactions provide great opportunities for developing simple yet effect metal ion probes. Different methods to design the chemically-modified QD hybrid structures through anchoring metal ion-specific groups onto the surface of QDs are summarized. Due to the spatial separation of the luminescence center and analyte recognition sites, these chemically-modified QDs offer greatly improved sensitivity and selectivity for metal ions. Several interesting applications of QD-based metal ion probes are presented, with specific emphasis on cellular probes, coding probes and sensing with logic gate operations.

Wu, Peng; Zhao, Ting; Wang, Shanling; Hou, Xiandeng

2013-12-01

106

Predicting wear and blood metal ion levels in metal-on-metal hip resurfacing.  

PubMed

Suboptimal component position and design are thought to lead to edge wear and raised blood metal ion levels in metal-on-metal hip resurfacing (MOM-HR). These factors are thought to influence the "contact patch to rim distance" (CPRD), and calculation of this distance may improve prediction of wear and blood metal ion levels. We measured blood cobalt and chromium ion levels and the wear rates of the bearing surfaces in 165 MOM-HR retrieval cases. We then determined the contribution and effect sizes of cup inclination and version angles, component size and design, and CPRD (calculated from case-specific data) on blood metal ion levels and component wear rates. Acetabular orientation explained between 16.3% and 28.5% of the variation in wear rates and metal ion levels, whereas component size and design explained between 7.3% and 21.8% of the variability. In comparison, CPRD explained up to 67.7% of the variability, significantly greater than any other variable (all p < 0.0001). CPRD is a good predictor of wear and improves our understanding of wear performance and the mechanisms leading to edge loading. PMID:24115200

Matthies, Ashley K; Henckel, Johann; Cro, Suzie; Suarez, Alexander; Noble, Philip C; Skinner, John; Hart, Alister J

2014-01-01

107

Separation of traces of metal ions from sodium matrices  

NASA Technical Reports Server (NTRS)

Method for isolating metal ion traces from sodium matrices consists of two extractions and an ion exchange step. Extraction is accomplished by using 2-thenoyltrifluoracetone and dithizone followed by cation exchange.

Korkisch, J.; Orlandini, K. A.

1969-01-01

108

Characterization of low temperature metallic magnetic calorimeters having gold absorbers with implanted $^{163}$Ho ions  

E-print Network

For the first time we have investigated the behavior of fully micro-fabricated low temperature metallic magnetic calorimeters (MMCs) after undergoing an ion-implantation process. This experiment had the aim to show the possibility to perform a high precision calorimetric measurement of the energy spectrum following the electron capture of $^{163}$Ho using MMCs having the radioactive $^{163}$Ho ions implanted in the absorber. The implantation of $^{163}$Ho ions was performed at ISOLDE-CERN. The performance of a detector that underwent an ion-implantation process is compared to the one of a detector without implanted ions. The results show that the implantation dose of ions used in this experiment does not compromise the properties of the detector. In addition an optimized detector design for future $^{163}$Ho experiments is presented.

L. Gastaldo; P. Ranitzsch; F. von Seggern; J. -P. Porst; S. Schäfer; C. Pies; S. Kempf; T. Wolf; A. Fleischmann; C. Enss; A. Herlert; K. Johnston

2012-06-25

109

Direct reaction measurements with a 132Sn radioactive ion beam  

E-print Network

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 cross section. The magnitude of the nuclear effects 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.

K. L. Jones; A. S. Adekola; D. W. Bardayan; J. C. Blackmon; K. Y. Chae; K. A. Chipps; J. A. Cizewski; L. Erikson; C. Harlin; R. Hatarik; R. Kapler; R. L. Kozub; J. F. Liang; R. Livesay; Z. Ma; B. H. Moazen; C. D. Nesaraja; F. M. Nunes; S. D. Pain; N. P. Patterson; D. Shapira; J. F. Shriner Jr; M. S. Smith; T. P. Swan; J. S. Thomas

2011-05-24

110

Plasma immersion surface modification with metal ion plasma  

SciTech Connect

We describe here a novel technique for surface modification in which metal plasma is employed and by which various blends of plasma deposition and ion implantation can be obtained. The new technique is a variation of the plasma immersion technique described by Conrad and co-workers. When a substrate is immersed in a metal plasma, the plasma that condenses on the substrate remains there as a film, and when the substrate is then implanted, qualitatively different processes can follow, including' conventional' high energy ion implantation, recoil implantation, ion beam mixing, ion beam assisted deposition, and metallic thin film and multilayer fabrication with or without species mixing. Multiple metal plasma guns can be used with different metal ion species, films can be bonded to the substrate through ion beam mixing at the interface, and multilayer structures can be tailored with graded or abrupt interfaces. We have fabricated several different kinds of modified surface layers in this way. 22 refs., 4 figs.

Brown, I.G.; Yu, K.M. (Lawrence Berkeley Lab., CA (USA)); Godechot, X. (Lawrence Berkeley Lab., CA (USA) Societe Anonyme d'Etudes et Realisations Nucleaires (SODERN), 94 - Limeil-Brevannes (France))

1991-04-01

111

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

112

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

113

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

NASA Astrophysics Data System (ADS)

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.; Vanini, S.; Benettoni, M.; Bonomi, G.; Calvini, P.; Checchia, P.; Conti, E.; Gonella, F.; Nebbia, G.; Squarcia, S.; Viesti, G.; Zenoni, A.; Zumerle, G.

2010-08-01

114

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

115

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

116

European research activities on charge state breeding related to radioactive ion beam facilities.  

PubMed

European effort on charge breeders is mainly dedicated to present and future Radioactive Ion Beam facilities. The main projects are High Intensity and Energy-ISOLDE at CERN, SPIRAL2 at GANIL, and EURISOL. Most of the experimental developments are funded by the European programs EURONS (European Nuclear Structure) and EURISOL (European Isotope Separation On-Line Radioactive Ion Beam Facility). Two ion source types (electron beam ion source and electron cyclotron resonance ion source) have been adapted to accept the injection and the capture of an ion beam, in order to increase its charge with the highest efficiency within the shortest time. Both charge breeders have advantages and disadvantages with regard to their use in a Radioactive Ion Beam facility. The most important parameters studied are acceptance (in emittance and intensity) of the charge breeder, efficiency, and charge breeding time of a specific n+ charge state, emittance of the extracted n+ beam. The charge breeder parameters are studied with different 1+ ion sources dedicated to 1+ radioactive ion beam production, and the tuning procedure of the charge breeder as a beam line section of a specific accelerator is established and measured too. PMID:18315164

Lamy, T; Angot, J; Thuillier, T

2008-02-01

117

Chromatographic Separations of Metal Ions on Zirconium Tungstoarsenate Impregnated Ion-Exchange Papers  

Microsoft Academic Search

A new heteropolyacid salt ion-exchanger, zirconium tungstoarsenate, has been used for preparing impregnated ion-exchange papers. Twenty-nine metal ions have been chromatographed and RF values determined in seven different mixed solvent systems containing 1-propanol and HNO or HCl. On the basis of the difference in selectivities for different metal ions on impregnated papers, a large number of binary and ternary separations

Ajay K. Jain; Sushma Agrawal; Raj P. Singh

1980-01-01

118

Breast milk metal ion levels in a young and active patient with a metal-on-metal hip prosthesis.  

PubMed

Metal-on-metal resurfacing arthroplasty of the hip has been used increasingly over the last 10 years in younger active patients. The dissolution of the metal wear particles results in measurable increases in cobalt and chromium ions in the serum and urine of patients with a metal-on-metal bearing. We measured the cobalt, chromium, and molybdenum ion levels in urine; serum; and breast milk in a young and active patient with a metal-on-metal hip prosthesis after a pathologic fracture of the femoral neck. Metal-on-metal hip prosthesis leads to increasing levels of molybdenum in breast milk in the short-term follow-up. There are no increasing levels of chromium and cobalt ions in breast milk. Besides the already known elevated concentrations in serum of chromium and cobalt after implantation of a metal-on-metal hip prosthesis, we found no increasing levels of chromium and cobalt in urine. PMID:22868068

Nelis, Raymond; de Waal Malefijt, Jan; Gosens, Taco

2013-01-01

119

Generation of radioactive ion species at daresbury laboratory  

Microsoft Academic Search

The generation of tritium and carbon-14 ion species is described. Tritium ions were produced from a commercial ion source which operated for a total period of 600 h, generating an average beam of 500 nA. Carbon-14 ions were produced from a refurbished sputter ion source which operated for 300 h generating an average beam of 450 nA. Working procedures for

T. R. Charlesworth; R. Ryder; M. P. Holbourn; D. J. Leeman

1986-01-01

120

A self-sputtering ion source: A new approach to quiescent metal ion beams  

SciTech Connect

A new metal ion source is presented based on sustained self-sputtering plasma in a magnetron discharge. Metals exhibiting high self-sputtering yield such as Cu, Ag, Zn, and Bi can be used in a high-power impulse magnetron sputtering discharge such that the plasma almost exclusively contains singly charged metal ions of the target material. The plasma and extracted ion beam are quiescent. The ion beams consist mostly of singly charged ions with a space-charge limited current density which reached about 10 mA/cm{sup 2} at an extraction voltage of 45 kV and a first gap spacing of 12 mm.

Oks, Efim [High Current Electronics Institute, Russian Academy of Sciences, 2/3 Academichesky Ave., Tomsk 634055 (Russian Federation); Anders, Andre [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720 (United States)

2010-02-15

121

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

122

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

123

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

124

Reactivity and Infrared Spectroscopy of Gaseous Hydrated Trivalent Metal Ions  

E-print Network

trivalent rare earth metal ions containing yttrium and all naturally abundant lanthanide metals are formed water cluster via a charge-separation process. This transition occurs over a narrow range of cluster The optical properties of lanthanide metals are strongly affected by interactions with water molecules, which

Cohen, Ronald C.

125

Reusable chelating resins concentrate metal ions from highly dilute solutions  

NASA Technical Reports Server (NTRS)

Column chromatographic method uses new metal chelating resins for recovering heavy-metal ions from highly dilute solutions. The absorbed heavy-metal cations may be removed from the chelating resins by acid or base washes. The resins are reusable after the washes are completed.

Bauman, A. J.; Weetal, H. H.; Weliky, N.

1966-01-01

126

Ion exchange and redox reactions in metal-ion exchanger nanocomposites  

NASA Astrophysics Data System (ADS)

The reducing sorption of oxygen dissolved in water with the use of metal-containing nanocomposites is considered taking into account the bifunctional nature of sorbents possessing both redox and ion exchange properties. A physicochemical model of the process including metal particle dispersity, their distribution over a grain, and the special features of the chemical oxidation of metals was used. Based on this model, a mathematical formulation of the problem including the stage of the interdiffusion of metal ions (metal oxidation products) and hydrogen ions (matrix counterions) is given.

Kipriyanova, E. S.; Konev, D. V.; Kravchenko, T. A.; Khorol'skaya, S. V.

2012-07-01

127

PERMANENT MAGNETS UNDER IRRADIATION AND RADIOACTIVE ALKALI ION BEAM DEVELOPMENT FOR SPIRAL 1  

E-print Network

elements is provided by a cold transfer tube, situated between the target cavity and the source chamber to the permanent magnets of the ion source (Nanogan III), which can then be damaged by neutron irradiation, leading Source Systems (TISSs) have been built and used for the production of radioactive ion beams on SPIRAL 1

Boyer, Edmond

128

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

129

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

130

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

131

Adhesive bonding of ion beam textured metals and fluoropolymers  

NASA Technical Reports Server (NTRS)

An electron bombardment argon ion source was used to ion etch various metals and fluoropolymers. The metal and fluoropolymers were exposed to (0.5 to 1.0) keV Ar ions at ion current densities of (0.2 to 1.5) mA/sq cm for various exposure times. The resulting surface texture is in the form of needles or spires whose vertical dimensions may range from tenths to hundreds of micrometers, depending on the selection of beam energy, ion current density, and etch time. The bonding of textured surfaces is accomplished by ion beam texturing mating pieces of either metals or fluoropolymers and applying a bonding agent which wets in and around the microscopic cone-like structures. After bonding, both tensile and shear strength measurements were made on the samples. Also tested, for comparison's sake, were untextured and chemically etched fluoropolymers. The results of these measurements are presented.

Mirtich, M. J.; Sovey, J. S.

1978-01-01

132

Linear radio frequency quadrupole for the cooling and bunching of radioactive ion beams  

SciTech Connect

A linear radio frequency quadrupole has been built for the transport, cooling, and bunching of radioactive ions extracted from an ECR source. The device uses the buffer gas cooling technique and was designed such as to extend the technique for the cooling of very light ions using H{sub 2} as buffer gas. We describe here the technical specifications of the device and present results of the first tests concerning the cooling and bunching of stable ions.

Darius, G.; Ban, G.; Bregeault, J.; Delahaye, P.; Desrues, Ph.; Durand, D.; Flechard, X.; Herbane, M.; Labalme, M.; LeBrun, Ch.; Lienard, E.; Mauger, F.; Merrer, Y.; Mery, A.; Naviliat-Cuncic, O.; Szerypo, J.; Vallerand, Ph.; Vandamme, Ch. [Laboratoire de Physique Corpusculaire, Caen (France); CERN-ISOLDE, Geneva (Switzerland); Laboratoire de Physique Corpusculaire, Caen (France); LPSC, Grenoble (France); Laboratoire de Physique Corpusculaire, Caen (France); Sekt. Phys., LMU, Munich (Germany); Laboratoire de Physique Corpusculaire, Caen (France)

2004-11-01

133

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

134

ADSORPTION OF RADIOACTIVE METALS BY STRONGLY MAGNETIC IRON SULFIDE NANOPARTICLES PRODUCED BY SULFATE-REDUCING BACTERIA  

Microsoft Academic Search

The adsorption of a number of radioactive ions from solution by a strongly magnetic iron sulfide material was studied. The material was produced by sulfate-reducing bacteria in a novel bioreactor. The uptake was rapid and loading on the adsorbent was high due to the high surface area of the adsorbent and because many of the ions were chemisorbed. The structural

J. H. P. Watson; I. W. Croudace; P. E. Warwick; P. A. B. James; J. M. Charnock; D. C. Ellwood

2001-01-01

135

Silica-polyamine composite materials for heavy metal ion removal, recovery, and recycling. 2. Metal ion separations from mine wastewater and soft metal ion extraction efficiency  

SciTech Connect

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 3,000 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 materials and reveals the results of tests designed to determine the effectiveness of these materials for extracting and separating metal ions from actual mining wastewater samples. Using these materials, the concentration of copper, aluminum, and zinc in Berkeley Pit mine wastewater is reduced to below allowable discharge limits. The recovered copper and zinc solutions were greater than 90% pure, and metal ion concentration factors of over 20 for copper were realized. Further, the ability of one of these materials to decrease low levels of the soft metals cadmium, mercury, and lead from National Sanitation Foundation recommended challenge levels to below Environmental Protection Agency allowable limits is also reported.

Fischer, R.J.; Pang, D.; Beatty, S.T.; Rosenberg, E.

1999-12-01

136

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. PMID:22048835

Cassat, James E.

2013-01-01

137

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

2010-07-15

138

Incorporation of impurity metal ions in electrolytic manganese dioxide  

SciTech Connect

The amounts of impurity metal ions incorporated into electrolytic manganese dioxide (EMD) during its preparation were measured as a function of metal ion concentration and current densities. The amount of incorporated ions increased in proportion to the concentration in solution, and at a fixed concentration it was different from ion to ion: Ni[sup 2+] < Zn[sup 2+] < Co[sup 2+] < Cu[sup 2+] < Fe[sup 2+] < Pb[sup 2+]. The specific surface area of the formed EMD was larger for impurity ions with higher incorporation affinity. Further, the adsorption of ions on the surface of a ready-made manganese dioxide sample (ICI2) was examined, and modeling of the adsorption behavior was attempted. The amounts of adsorbed ions at a fixed concentration in solution and pH 0.7 (where EMD is produced) were obtained by the ion-adsorption model. There was a strong correlation between the amount incorporated and the amount of adsorption, suggesting a mechanism in which EMD is contaminated through adsorption on its new growing surface. The increase in specific surface area of EMD with contaminants was interpreted to be due to a suppression of the growth of EMD at the adsorbed foreign ion sites, resulting in EMD with many defects or smaller particle sizes. The opposite effect of current density on incorporation for the two groups of metal ions was discussed.

Tamura, Hiroki; Ishizeki, Kenji; Nagayama, Masaichi; Furuichi, Ryusaburo (Hokkaido Univ., Sapporo (Japan). Faculty of Engineering)

1994-08-01

139

The role of metal corrosion in inflammatory processes: induction of adhesion molecules by heavy metal ions  

Microsoft Academic Search

Prosthetic devices undergo corrosion processes after implantation including the release of certain amounts of metal ions into the adjacent tissues. On reaching the bloodstream, a systemic influence of those ions may be envisaged. Cell adhesion molecules (CAMs) are recognized as an essential component of the mechanisms of endothelial damage. To study the influence of selected heavy metals on human umbilical

C. L. Klein; P. Nieder; M. Wagner; H. Köhler; F. Bittinger; C. J. Kirkpatrick; J. C. Lewis

1994-01-01

140

Characterization of Solidified Products Yielded by Plasma Melting Treatment of Simulated Non-Metallic Radioactive Wastes  

Microsoft Academic Search

As a part of an advanced volume reduction program for low level radioactive wastes in JAERI, melting tests of non-metallic solid wastes have been conducted with the aim of establishing the optimum melting condition for preparation of a stable solid that is suitable for disposal. Simulated non-metallic wastes containing Co, Cs and Eu tracers were melted with a plasma torch

Mikio NAKASHIMA; Toshiki FUKUI; Nobuyuki NAKASHIO; Motoyasu ISOBE; Atsushi OHTAKE; Takuji WAKUI; Takakuni HIRABAYASHI

2002-01-01

141

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

142

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

143

Modeling Multi-Metal Ion Exchange in Biosorption  

E-print Network

by protonated Sargassum fluitans biomass in systems containing two metal ions and protons at different pH values by the brown alga Sargassum fluitans, which contains the carboxyl groups of alginate and the sulfate groups

Volesky, Bohumil

144

Metallic glass as a temperature sensor during ion plating  

NASA Technical Reports Server (NTRS)

The temperature of the interface and/or a superficial layer of a substrate during ion plating was investigated using a metallic glass of the composition Fe67Co18B14Si1 as the substrate and as the temperature sensor. Transmission electron microscopy and diffraction studies determined the microstructure of the ion-plated gold film and the substrate. Results indicate that crystallization occurs not only in the film, but also in the substrate. The grain size of crystals formed during ion plating was 6 to 60 nm in the gold film and 8 to 100 nm in the substrate at a depth of 10 to 15 micrometers from the ion-plated interface. The temperature rise of the substrate during ion plating was approximately 500 C. Discontinuous changes in metallurgical microstructure, and physical, chemical, and mechanical properties during the amorphous to crystalline transition in metallic glasses make metallic glasses extremely useful materials for temperature sensor applications in coating processes.

Miyoshi, K.; Spalvins, T.; Buckley, D. H.

1985-01-01

145

Metallic glass as a temperature sensor during ion plating  

NASA Technical Reports Server (NTRS)

The temperature of the interface and/or a superficial layer of a substrate during ion plating was investigated using a metallic glass of the composition Fe67Co18B14Si1 as the substrate and as the temperature sensor. Transmission electron microscopy and diffraction studies determined the microstructure of the ion-plated gold film and the substrate. Results indicate that crystallization occurs not only in the film, but also in the substrate. The grain size of crystals formed during ion plating was 6 to 60 nm in the gold film and 8 to 100 nm in the substrate at a depth of 10 to 15 micrometers from the ion-plated interface. The temperature rise of the substrate during ion plating was approximately 500 C. Discontinuous changes in metallurgical microstructure, and physical, chemical, and mechanical properties during the amorphous to crystalline transition in metallic glasses make metallic glasses extremely useful materials for temperature sensor applications in coating processes.

Miyoshi, K.; Spalvins, T.; Buckley, D. H.

1984-01-01

146

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

147

Smart textile device using ion polymer metal compound.  

PubMed

We have developed a smart textile device that detects angular displacement of attached surface using ion polymer metal compound. The device was composed of ion polymer metal compound (IPMC) which was fabricated from Nafion resin by heat-press and chemical gold plating. The generated voltage from IPMC was measured as a function of bending angle. Fabricated IPMC device was weaved into a cotton cloth and multidirectional movements were detected. PMID:24109750

Nakamura, Taro; Ihara, Tadashi

2013-01-01

148

Removal of toxic metal ions from wastewater by semiconductor photocatalysis  

Microsoft Academic Search

Semiconductor photocatalytic reduction is a relatively new technique for the removal of dissolved metal ions in wastewater. In this paper, physical adsorption and photocatalytic reduction of eight environmentally significant metal ions in TiO2 suspensions of Degussa P25 and Hombikat UV100 were investigated. Critical scrutiny of the potential versus pC and pH diagrams reveals that any particular oxidation or reduction reaction

Dingwang Chen; Ajay K. Ray

2001-01-01

149

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

150

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

151

Latest developments at GANIL for stable and radioactive ion beam productiona)  

NASA Astrophysics Data System (ADS)

In the frame of the SPIRAL II (Système de Production d'Ions Radioactifs Accélérés en Ligne Partie II) project, several developments of stable and radioactive ion production systems have been started up. In parallel, GANIL has the ambition to preserve the existing stable and radioactive beams and also to increase its range by offering new ones. In order to identify the best directions for this development, a new group called GANISOL has been formed. Its preliminary conclusions and the latest developments at GANIL are presented.

Jardin, P.; Barué, C.; Bajeat, O.; Canet, C.; Clément, E.; Cornell, J. C.; Delahaye, P.; Dubois, M.; Dupuis, M.; Flambard, J. L.; Frânberg, H.; Frigot, R.; Leboucher, C.; Lecesne, N.; Lecomte, P.; Lehérissier, P.; Lemagnen, F.; Leroy, R.; Maunoury, L.; Méry, A.; De Oliveira, F.; Pichard, A.; Pacquet, J.-Y.; Saint-Laurent, M.-G.; Thomas, J. C.

2010-02-01

152

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

153

Structural Metals in the Group I Intron: A Ribozyme with a Multiple Metal Ion Core  

SciTech Connect

Metal ions play key roles in the folding and function for many structured RNAs, including group I introns. We determined the X-ray crystal structure of the Azoarcus bacterial group I intron in complex with its 5' and 3' exons. In addition to 222 nucleotides of RNA, the model includes 18 Mg2+ and K+ ions. Five of the metals bind within 12 Angstroms of the scissile phosphate and coordinate the majority of the oxygen atoms biochemically implicated in conserved metal-RNA interactions. The metals are buried deep within the structure and form a multiple metal ion core that is critical to group I intron structure and function. Eight metal ions bind in other conserved regions of the intron structure, and the remaining five interact with peripheral structural elements. Each of the 18 metals mediates tertiary interactions, facilitates local bends in the sugar-phosphate backbone or binds in the major groove of helices. The group I intron has a rich history of biochemical efforts aimed to identify RNA-metal ion interactions. The structural data are correlated to the biochemical results to further understand the role of metal ions in group I intron structure and function.

Stahley,M.; Adams, P.; Wang, J.; Strobel, S.

2007-01-01

154

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

155

Influence of electrode geometry on liquid metal ion source performance  

Microsoft Academic Search

The surface electric field distribution along the axis of a wetted needle type liquid metal ion source has been determined by numerical methods and is shown to exhibit a secondary maximum at the intersection of the cylindrical and conical sections. It is shown that the volume flow rate of the liquid metal film along the cylindrical portion of the emitter

L. W. Swanson; J. Z. Li

1988-01-01

156

Synergistic Catalysis of Dimetilan Hydrolysis by Metal Ions and  

E-print Network

such as extracellular enzymes. Introduction Hydrolysis is believed to be the predominant degradation pathway that dissolved metal ions (1), simple hydrous metal oxides (2-5), and clays (6, 7) can increase hydrolysis rates of agrochemicals dramatically. Catalysis may arise from reaction of the added chemical constituent with the agro

Huang, Ching-Hua

157

Surface Precipitation of Hydrolyzable Metal Ions on Oxide Surfaces  

E-print Network

Surface Precipitation of Hydrolyzable Metal Ions on Oxide Surfaces S. E. Fendorf Heavy metalO2 and TiO2 near and beyond monolayer coverage. Surface precipitation of Al(III) and La(III) was observed on MnO2, but was not apparent on TiO2 nor in bulk solution. Al(III) formed a surface precipitate

Sparks, Donald L.

158

Dissociative Grazing Scattering of H2 + Ions from Metal Surfaces  

E-print Network

Dissociative Grazing Scattering of H2 + Ions from Metal Surfaces Igor Wojciechowski, Marina from grazing scattering of H2 + from metal surfaces are calculated analytically and by using classical are typical for the activation of chemical reactions on a surface. Thus, the use of grazing scattering

159

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

160

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, Paul J. (Los Alamos, NM); Delhaize, Emmanuel (Los Alamos, NM); Robinson, Nigel J. (Durham, GB2); Unkefer, Clifford J. (Los Alamos, NM); Furlong, Clement (Seattle, WA)

1990-01-01

161

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 unit 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 heayv metals from solution. This also results in the removal of the metals from the column in a concentrated form.

Jackson, Paul J. (both Los Alamos, NM); Delhaize, Emmanuel (both Los Alamos, NM); Robinson, Nigel J. (Durham, GB2); Unkefer, Clifford J. (Los Alamos, NM); Furlong, Clement (Seattle, WA)

1990-11-13

162

Plasma spectroscopy of metal ions for hyper-electron cyclotron resonance ion source.  

PubMed

In this research, the optical line spectra of metal ions from ECR plasma were observed using a grating monochromator with a photomultiplier. The light intensity of line spectrum from the ECR plasma had a strong correlation with ion beam intensity measured by a magnetic mass analyzer. This correlation is a significant information for the beam tuning process, because it allows to conduct the extraction of the desired metal ion species from the ECR plasma. Separation of ion species of the same charge to mass ratio with an electromagnetic mass analyzer is known to be an exceptionally complex process, but this research provides a new approach for its simplification. In this paper the grating monochromator method for metal ion beam tuning such as (40)Ca(12+), (56)Fe(15+), and (85)Rb(20+) of hyper-ECR ion source as an injector for RIKEN Azimuthal Varying Field cyclotron is described. PMID:24593484

Muto, Hideshi; Ohshiro, Yukimitsu; Yamaka, Shoichi; Watanabe, Shin-ichi; Oyaizu, Michihiro; Kubono, Shigeru; Yamaguchi, Hidetoshi; Kase, Masayuki; Hattori, Toshiyuki; Shimoura, Susumu

2014-02-01

163

RATIONAL DESIGN OF METAL ION SEQUESTERING AGENTS  

EPA Science Inventory

An enormous amount of radioactive and toxic chemical waste remains at over one hundred sites managed by the Department of Energy. Despite the investment of large sums, major goals associated with the cleanup remain unmet. It is our thesis that economically practical accomplishmen...

164

Holifield Radioactive Ion Beam Facility A leading international facility with unique capabilities for research in nuclear structure  

E-print Network

HRIBF Holifield Radioactive Ion Beam Facility A leading international facility with unique (+26 more unaccelerated) · 32 proton-rich species · 143 neutron-rich species The Holifield Radioactive a dedicated user program in nuclear physics using exotic beams. Radioactive species are produced by intense

165

Neutralization by Metal Ions of the Toxicity of Sodium Selenide  

PubMed Central

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

2013-01-01

166

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

167

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 new kind of high current metal ion source in which the ion beam is extracted from a metal vapor vacuum arc plasma has been used to obtain the spectra of multiply charged ions produced within the cathode spots. The cathode materials used and the species reported on here are: C, Mg, Al, Si, Ti, Cr, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, Rh, Pd, Ag, In, Sn, Gd, Ho, Ta, W, Pt, Au, Pb, Th, and U; the arc current was 200 A for all measurements. Charge state spectra were measured using a time-of-flight method. In this paper we report on the measured charge state distributions and arc voltages and compare the distributions with the predictions of a theory in which ionization occurs in the cathode spots via stepwise ionization by electron impact.

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

1988-05-15

168

Sorption of metal ions from aqueous solution using bone char.  

PubMed

The sorption of cadmium, copper and zinc from aqueous solutions onto bone char has been studied in both single and binary multi-component systems. Equilibrium experimental studies have been performed to determine the sorption capacity of bone char for each metal ion. The isotherm results have been analysed using single and multi-component equilibrium models. The rate of sorption of the metal ions onto bone char has been studied using an agitated batch adsorber. The concentration versus time decay curves have been measured and a number of mass transfer models have been developed and tested based on diffusion controlled sorption. The results of the equilibrium and rate studies are presented and discussed in the paper. The possible mechanisms of metal sorption are also discussed. Finally a series of fixed bed column studies have been performed and analysed using a diffusion mass transport model. The experimental results show a displacement effect for the binary metal ion breakthrough curves. PMID:16023725

Choy, Keith K H; McKay, Gordon

2005-08-01

169

Sorption of Heavy Metal Ions on New Metal-Ligand Complexes Chemically Derived from Lycopodium clavatum  

Microsoft Academic Search

Sorption of heavy metal ions from aqueous solution has been investigated as a function of pH using a novel exchanger system whereby Lycopodium clavatum is functionalized with carboxylate and glyoxime metal-ligand complexes. The new ligand exchangers were prepared using a reaction of diaminosporopollenin with various metal-ligand complexes of glyoxime and monocarboxylic acid. The sorptive behavior of these metal-ligand exchangers and

Erol Pehlivan; Mustafa Ersoz; Salih Yildiz; Harry J. Duncan

1994-01-01

170

Transition Metal Speciation in the Cell: Insights from the Chemistry of Metal Ion Receptors  

NSDL National Science Digital Library

The essential transition metal ions are avidly accumulated by cells, yet they have two faces: They are put to use as required cofactors, but they also can catalyze cytotoxic reactions. Several families of proteins are emerging that control the activity of intracellular metal ions and help confine them to vital roles. These include integral transmembrane transporters, metalloregulatory sensors, and diffusible cytoplasmic metallochaperone proteins that protect and guide metal ions to targets. It is becoming clear that many of these proteins use atypical coordination chemistry to accomplish their unique goals. The different coordination numbers, types of coordinating residues, and solvent accessibilities of these sites are providing insight into the inorganic chemistry of the cytoplasm.

Lydia Finney (Northwestern University;Department of Chemistry, Molecular Biology and Cell Biology); Thomas O'Halleron (Northwestern University;Department of Biochemistry, Molecular Biology and Cell Biology)

2003-05-09

171

Therapeutic redistribution of metal ions to treat Alzheimer's disease.  

PubMed

Currently, therapeutics that modify Alzheimer's disease (AD)are not available. Increasing age is the primary risk factor for AD and due to an aging global population the urgent need for effective therapeutics increases every year. This Account presents the development of an AD treatment strategy that incorporates diverse compounds with a common characteristic: the ability to redistribute metal ions within the brain. Central to cognitive decline in AD is the amyloid-? peptide (A?) that accumulates in the AD brain. A range of therapeutic strategies have been developed based on the premise that decreasing the brain A? burden will attenuate the severity of the disease symptoms. Unfortunately these treatments have failed to show any positive outcomes in large-scale clinical trials, raising many questions regarding whether therapeutics for AD can rely solely on decreasing A? levels. An alternate strategy is to target the interaction between A? and metal ions using compounds with the potential to redistribute metal ions within the brain. The original rationale for this strategy came from studies showing that metal ions promote A? toxicity and aggregation. In initial studies using the prototype metal-chelating compound clioquinol (CQ), CQ prevented A? toxicity in vitro, out-competed A? for metal ions without affecting the activity of metal-dependent enzymes, and attenuated the rate of cognitive decline in AD subjects in a small phase II clinical trial. All these outcomes were consistent with the original hypothesized mechanism of action for CQ where prevention or reversal of the extracellular A?-metal interactions could prevent A? toxicity. Soon after the completion of these studies, a new body of work began to suggest that this hypothesized mechanism of action for CQ was simplistic and that other factors were also important for the positive therapeutic outcomes. Perhaps most significantly, it was shown that after CQ sequesters metal ions the neutral CQ-metal complex crosses cell membranes to increase intracellular levels of the metals, thereby initiating protective cell signaling cascades. The activity of CQ therefore appeared to be two-fold: it prevented toxic interactions between A? and metal ions outside the cell, and it redistributed the metal ions into the cell to promote healthy cell function. To determine the significance of redistributing metal ions into the cell, glyoxalbis(N(4)-methylthiosemicarbazonato)Cu(II) [Cu(II)(gtsm)] was tested in models of AD. Cu(II)(gtsm) delivers Cu into cells, but, unlike CQ, it cannot out-compete A? for metal ions. When tested in AD model mice, the Cu(II)(gtsm) treatment restored cognitive function back to levels expected for cognitively healthy mice. The most advanced compound from this therapeutic strategy, PBT2, can sequester metal ions from A? and redistribute them into the cell like CQ. PBT2 improved cognition in a phase II clinical trial with AD patients, and further clinical testing is currently underway. PMID:22747493

Crouch, Peter J; Barnham, Kevin J

2012-09-18

172

Measuring neutrino mass with radioactive ions in a storage ring  

E-print Network

We propose a method to measure the neutrino mass kinematically using beams of ions which undergo beta decay. The idea is to tune the ion beam momentum so that in most decays, the electron is forward moving with respect to the beam, and only in decays near the endpoint is the electron moving backwards. Then, by counting the backward moving electrons one can observe the effect of neutrino mass on the beta spectrum close to the endpoint. In order to reach sensitivities for $m_\

Mats Lindroos; Bob McElrath; Christopher Orme; Thomas Schwetz

2009-04-07

173

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

E-print Network

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 sub-saturation 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.

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

2013-10-03

174

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

175

Does Ion Release Differ Between Hip Resurfacing and Metal-on-metal THA?  

PubMed Central

Modern metal-on-metal hip resurfacing was introduced as a bone-preserving method of joint reconstruction for young and active patients; however, the large diameter of the bearing surfaces is of concern for potential increased metal ion release. We hypothesized there were no differences in serum concentrations of chromium, cobalt, and molybdenum between patients who had metal-on-metal hip resurfacing (Group A; average head diameter, 48 mm; median followup, 24 months) and patients who had 28-mm metal-on-metal THA (Group B; median followup, 25 months). Serum concentrations also were compared with concentrations in healthy subjects. We identified no differences in ion levels between Groups A and B. A distinction was made according to gender. Women showed a higher chromium release in Group A whereas men had a higher cobalt release in Group B. Values obtained from Group A were higher than those of the control subjects. Our data suggest metal-on-metal bearings for THA should not be rejected because of concern regarding potential increased metal ion release; however, patients with elevated ion levels, even without loosening or toxicity, could be at higher risk and should be followed up periodically. Level of Evidence: Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence. PMID:18196364

Moroni, Antonio; Cadossi, Matteo; Baldini, Nicola; Giannini, Sandro

2008-01-01

176

Development of melt refining decontamination technology for low level radioactive metal waste contaminated with uranium  

NASA Astrophysics Data System (ADS)

The feasibility study of Melt Refining Decontamination by Slagging (MRDS) havs been performed for the release and recycling of Low Level Radioactive Metal Waste (LLRMW) contaminated with uranium discharged from nuclear fuel cycle facilities. Experiments and their evaluation have been performed for the decontamination performance of the waste containing aluminum and have clarified the followings. Simulated waste was decontaminated to 0.01 Bq/g when the addition of aluminum is below 1.5 wt% in laboratory scale test equipment. This was demonstrated also in the engineering scale experiment for MRDS. These results demonstrate that the MRDS is an effective processing technology for low level radioactive metal waste with uranium.

Aoyama, M.; Miyamoto, Y.; Fukumoto, M.; Suto, O.

2005-02-01

177

Characterization of low temperature metallic magnetic calorimeters having gold absorbers with implanted 163Ho ions  

NASA Astrophysics Data System (ADS)

For the first time we have investigated the behavior of fully micro-fabricated low temperature metallic magnetic calorimeters (MMCs) after undergoing an ion-implantation process. This experiment had the aim to show the possibility to perform a high precision calorimetric measurement of the energy spectrum following the electron capture of 163Ho using MMCs having the radioactive 163Ho ions implanted in the absorber. The isotope 163Ho decays through electron capture to 163Dy and features the smallest known QEC value. This peculiarity makes 163Ho a very interesting candidate to investigate the value of the electron neutrino mass by the analysis of the energy spectrum. The implantation of 163Ho ions was performed at ISOLDE-CERN. The performance of a detector that underwent an ion-implantation process is compared to the one of a detector without implanted ions. The results show that the implantation dose of ions used in this experiment does not compromise the properties of the detector. Moreover the performance of the detector prototype having the 163Ho ions implanted in the absorber is already close to the requirements needed for an experiment with sub-eV sensitivity to the electron neutrino mass. Based on these results, an optimized detector design for future 163Ho experiments is presented.

Gastaldo, L.; Ranitzsch, P. C.-O.; von Seggern, F.; Porst, J.-P.; Schäfer, S.; Pies, C.; Kempf, S.; Wolf, T.; Fleischmann, A.; Enss, C.; Herlert, A.; Johnston, K.

2013-05-01

178

Fluorescent carbon nanoparticles for the fluorescent detection of metal ions.  

PubMed

Fluorescent carbon nanoparticles (F-CNPs) as a new kind of fluorescent nanoparticles, have recently attracted considerable research interest in a wide range of applications due to their low-cost and good biocompatibility. The fluorescent detection of metal ions is one of the most important applications. In this review, we first present the general detection mechanism of F-CNPs for the fluorescent detection of metal ions, including fluorescence turn-off, fluorescence turn-on, fluorescence resonance energy transfer (FRET) and ratiometric response. We then focus on the recent advances of F-CNPs in the fluorescent detection of metal ions, including Hg(2+), Cu(2+), Fe(3+), and other metal ions. Further, we discuss the research trends and future prospects of F-CNPs. We envision that more novel F-CNPs-based nanosensors with more accuracy and robustness will be widely used to assay and remove various metal ions, and there will be more practical applications in coming years. PMID:25058940

Guo, Yongming; Zhang, Lianfeng; Zhang, Shushen; Yang, Yan; Chen, Xihan; Zhang, Mingchao

2015-01-15

179

Highly sensitive colour change system within slight differences in metal ion concentrations based on homo–binuclear complex formation equilibrium for visual threshold detection of trace metal ions  

Microsoft Academic Search

A new technique of expressing slight differences in metal ion concentrations by clear difference in colour was established for visual threshold detection of trace metal ions. The proposed method is based on rapid change of the mole fraction of the homo–binuclear complex (M2L) about a ligand in a narrow range of the total metal ion concentration (MT) in a small

Hitoshi Mizuguchi; Hiroshi Atsumi; Keigo Hashimoto; Yasuhiro Shimada; Yuki Kudo; Masatoshi Endo; Fumihiko Yokota; Junichi Shida; Takao Yotsuyanagi

2004-01-01

180

Intensity limitations of a gas cell for stopping, storing and guiding of radioactive ions  

NASA Astrophysics Data System (ADS)

The possibility to use a gas cell filled with noble gas (He or Ar) for thermalizing, storing and transporting radioactive ions is explored by studying experimentally ion-electron recombination of stable Ni, resonantly ionized by laser light. Combined with a literature study on ionization chambers, especially developed for high-intensity applications, conclusions are drawn on the maximum intensity of the incoming ion beam. A practical limit is encountered when the space-charge induced voltage fully counteract the applied voltage on the electrodes collecting the electrons.

Huyse, Mark; Facina, Marius; Kudryavtsev, Yuri; van Duppen, Piet; Isolde Collaboration

2002-04-01

181

Metal ion release kinetics from nanoparticle silicone composites.  

PubMed

Metal ion release kinetics from silver and copper nanoparticle silicone composites generated by laser ablation in liquids are investigated. The metal ion transport mechanism is studied by using different model equations and their fit to experimental data. Results indicate that during the first 30 days of immersion, Fickian diffusion is the dominant transport mechanism. After this time period, the oxidation and dissolution of nanoparticles from the bulk determine the ion release. This second mechanism is very slow since the dissolution of the nanoparticle is found to be anisotropic. Silver ion release profile is best described by pseudo-first order exponential equation. Copper ion release profile is best described by a second order exponential equation. For practical purposes, the in vitro release characteristics of the bioactive metal ions are evaluated as a function of nanoparticle loading density, the chemistry and the texture of the silicone. Based on the proposed two-step release model, a prediction of the release characteristics over a time course of 84 days is possible and a long-term ion release could be demonstrated. PMID:21645564

Hahn, Anne; Brandes, Gudrun; Wagener, Philipp; Barcikowski, Stephan

2011-09-01

182

Radioactive halos and ion microprobe measurement of Pb isotope ratios  

NASA Technical Reports Server (NTRS)

This investigation was to obtain, if possible, the Pb isotope ratios of both lunar and meteoritic troilite grains by utilizing ion microprobe techniques. Such direct in situ measurement of Pb isotope ratios would eliminate contamination problems inherent in wet chemistry separation procedures, and conceivably determine whether lunar troilite grains were of meteoritic origin. For comparison purposes two samples of meteoritic troilite were selected (one from Canyon Diablo) for analysis along with two very small lunar troilite grains (approximately 50-100 microns). It was concluded that the ion microprobe as presently operating, does not permit the in situ measurement of Pb isotope ratios in lunar or meteoritic troilite. On the basis of these experiments no conclusions could be drawn as to the origin of the lunar troilite grains.

Gentry, R. V.

1974-01-01

183

Preliminary shielding estimates for the proposed Oak Ridge National Laboratory (ORNL) Radioactive Ion Beam Facility (RIBF)  

SciTech Connect

The Oak Ridge National Laboratory (ORNL) has proposed designing and implementing a new target-ion source for production and injection of negative radioactive ion beams into the Hollifield tandem accelerator. This new facility, referred to as the Radioactive Ion Beam Facility (RIBF), will primarily be used to advance the scientific communities` capabilities for performing state-of-the-art cross-section measurements. Beams of protons or other light, stable ions from the Oak Ridge Isochronous Cyclotron (ORIC) will be stopped in the RIBF target ion source and the resulting radioactive atoms will be ionized, charge exchanged, accelerated, and injected into the tandem accelerator. The ORIC currently operates with proton energies up to 60 MeV and beam currents up to 100 microamps with a maximum beam power less than 2.0 kW. The proposed RIBF will require upgrading the ORIC to generate proton energies up to 200 MeV and beam currents up to 200 microamps for optimum performance. This report summarizes the results of a preliminary one-dimensional shielding analysis of the proposed upgrade to the ORIC and design of the RIBF. The principal objective of the shielding analysis was to determine the feasibility of such an upgrade with respect to existing shielding from the facility structure, and additional shielding requirements for the 200 MeV ORIC machine and RIBF target room.

Johnson, J.O.; Gabriel, T.A.; Lillie, R.A.

1996-02-01

184

Grid-controlled metal ion sources for heavy ion fusion accelerators  

Microsoft Academic Search

A variety of metal ions can be generated using vacuum arcs, but due to the nature of these arcs, the flux generated fluctuates in time. We have successfully employed electrostatically biased grids to control the plasma and to provide a well-behaved, space charge limited ion source. The grid prevents the plasma from entering the extraction gap before the main voltage

L. K. Len; S. Jr. Humphries; C. Burkhart

1986-01-01

185

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/cm 2 and 1 ?A primary proton beam current, 1.4 × 10 6 pps for 91Kr, 7 × 10 5 pps for 126In, 2.6 × 10 6 pps for 138Xe, respectively. Using a surface ionization type ion source, under the same normalization, the separation yields of 1.8 × 10 7 pps for 93Rb, 6 × 10 7 pps for 94Sr, 2.5 × 10 6 pps for 143Cs and 5 × 10 6 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

186

Low coefficient of thermal expansion polyimides containing metal ion additives  

NASA Technical Reports Server (NTRS)

Polyimides have become widely used as high performance polymers as a result of their excellent thermal stability and toughness. However, lowering their coefficient of thermal expansion (CTE) would increase their usefulness for aerospace and electronic applications where dimensional stability is a requirement. The incorporation of metal ion-containing additives into polyimides, resulting in significantly lowered CTE's, has been studied. Various metal ion additives have been added to both polyamic acid resins and soluble polyimide solutions in the concentration range of 4-23 weight percent. The incorporation of these metal ions has resulted in reductions in the CTE's of the control polyimides of 12 percent to over 100 percent depending on the choice of additive and its concentration.

Stoakley, D. M.; St. Clair, A. K.

1992-01-01

187

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

188

Metal-ion recycle technology for metal electroplating waste waters.  

National Technical Information Service (NTIS)

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 th...

N. N. Sauer, B. F. Smith

1993-01-01

189

Adsorption characteristics of UO(2)(2+) and Th(4+) ions from simulated radioactive solutions onto chitosan/clinoptilolite sorbents.  

PubMed

Adsorption features of UO(2)(2+) and Th(4+) ions from simulated radioactive solutions onto a novel chitosan/clinoptilolite (CS/CPL) composite as beads have been investigated compared with chitosan cross-linked with epichlorohydrin. The effects of contact time, the initial metal ion concentration, sorbent mass and temperature on the adsorption capacity of the CS-based sorbents were investigated. The adsorption kinetics was well described by the pseudo-second order equation, and the adsorption isotherms were better fitted by the Sips model. The maximum experimental adsorption capacities were 328.32 mg Th(4+)/g composite, and 408.62 mg UO(2)(2+)/g composite. The overall adsorption tendency of CS/CPL composite toward UO(2)(2+) and Th(4+) radiocations in the presence of Cu(2+), Fe(2+) and Al(3+), under competitive conditions, followed the order: Cu(2+)>UO(2)(2+)>Fe(2+)>Al(3+), and Cu(2+)>Th(4+)>Fe(2+)>Al(3+), respectively. The negative values of Gibbs free energy of adsorption indicated the spontaneity of the adsorption of radioactive ions on both the CS/CPL composite and the cross-linked CS. The desorption level of UO(2)(2+) from the composite CS/CPL, by using 0.1M Na(2)CO(3), was around 92%, and that of Th(4+) ions, performed by 0.1M HCl, was around 85%, both values being higher than the desorption level of radiocations from the cross-linked CS, which were 89% and 83%, respectively. PMID:20943312

Humelnicu, Doina; Dinu, Maria Valentina; Dr?gan, Ecaterina Stela

2011-01-15

190

Ion source developments for the production of radioactive isotope beams at TRIUMFa)  

NASA Astrophysics Data System (ADS)

At the ISAC facility at TRIUMF radioactive ions are produced by bombarding solid targets with up to 100 ?A of 500 MeV protons. The reaction products have to diffuse out of the hot target into an ion source. Normally, singly charged ions are extracted. They can be transported either directly to experiments or via an ECR charge state breeder to a post accelerator. Several different types of ion sources have to be used in order to deliver a large variety of rare isotope beams. At ISAC those are surface ion sources, forced electron beam arc discharge (FEBIAD) ion sources and resonant laser ionization sources. Recent development activities concentrated on increasing the selectivity for the ionization to suppress isobaric contamination in the beam. Therefore, a surface ion rejecting resonant laser ionization source (SIRLIS) has been developed to suppress ions from surface ionization. For the FEBIAD ion source a cold transfer line has been introduced to prevent less volatile components from reaching the ion source.

Ames, F.; Bricault, P.; Heggen, H.; Kunz, P.; Lassen, J.; Mjøs, A.; Raeder, S.; Teigelhöfer, A.

2014-02-01

191

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

192

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

193

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

194

Comet Encke: Meteor metallic ion identification by mass spectrometer  

NASA Technical Reports Server (NTRS)

Metal ions including Na-40(+), Mg-24(+), Si-28(+), K-39(+), Ca-40(+), Sc-45(+), Cr-52(+), Fe-56(+), and Ni-58(+) were detected in the upper atmosphere during the beta Taurids meteor shower. Abundances of these ions relative to Si(+) show agreement in most instances with chondrites. A notable exception is 45(+), which is Sc(+), is 100 times more abundant than neutral scandium found in chondrites.

Goldberg, R. A.; Aikin, A. C.

1972-01-01

195

Mechanism of silica-metal mixing by ion irradiation  

Microsoft Academic Search

The application of ion-beam mixing to the doping of silica films with metals either in solution or in the form of nanoclusters requires a preliminary investigation of the mixing mechanisms. This was undertaken by means of RBS and XRD for Au, Pt, W, Ag and Cu films mixed with silica by 4.5 MeV Au or 200 keV Ar ions, at

J. C. Pivin; P. Colombo

1997-01-01

196

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-diam 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 pulsewidth, at present, of 0.25 ms and a repetition rate of up to several tens of pulses per second (power supply limited). The multi-cathode feature that was developed for the prior source version, MEVVA IV, has been incorporated here also; one can switch among any of 18 separate cathodes and thus metallic beam species. Maximum beam extraction voltage is over 90 kV, and since the ion charge states are typically from {ital 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 article we describe the source, and present some preliminary results.

Brown, I.G.; Galvin, J.E.; MacGill, R.A. (Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720 (US)); Paoloni, F.J. (Electrical Engineering Department, University of Wollongong, Wollongong NSW 2500, (Australia))

1990-01-01

197

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

198

Sorption of heavy metal ions on new metal-ligand complexes chemically derived from Lycopodium clavatum  

SciTech Connect

Sorption of heavy metal ions from aqueous solution has been investigated as a function of pH using a novel exchanger system whereby Lycopodium clavatum is functionalized with carboxylate and glyoxime metal-ligand complexes. The new ligand exchangers were prepared using a reaction of diaminosporopollenin with various metal-ligand complexes of glyoxime and monocarboxylic acid. The sorptive behavior of these metal-ligand exchangers and the possibilities to remove and to recover selectively heavy metal cations using these systems are discussed on the basis of their chemical natures and their complexing properties.

Pehlivan, E.; Ersoz, M.; Yildiz, S. [Univ. of Selcuk, Konya (Turkey); Duncan, H.J. [Univ. of Glasgow, Scotland (United Kingdom)

1994-08-01

199

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

2009-03-01

200

Metal-Ion Additives Reduce Thermal Expansion Of Polyimides  

NASA Technical Reports Server (NTRS)

Polyimides widely used as high-performance polymers because of their excellent thermal stability and toughness. However, their coefficients of thermal expansion (CTE's) greater than those of metals, ceramics, and glasses. Decreasing CTE's of polyimides increase usefulness for aerospace and electronics applications in which dimensional stability required. Additives containing metal ions reduce coefficients of thermal expansion of polyimides. Reductions range from 11 to over 100 percent.

Stoakley, Diane M.; St. Clair, Anne K.; Emerson, Burt R., Jr.; Willis, George L.

1994-01-01

201

Sensing Metal Ions with DNA Building Blocks: Fluorescent Pyridobenzimidazole Nucleosides  

PubMed Central

We describe novel fluorescent N-deoxyribosides (1 and 2) having 2-pyrido-2-benzimidazole and 2-quino-2-benzimidazole as aglycones. The compounds were prepared from the previously unknown heterocyclic precursors and Hoffer’s chlorosugar, yielding alpha anomers as the chief products. X-ray crystal structures confirmed the geometry, and showed that the pyridine and benzimidazole ring systems deviated from coplanarity in the solid state by 154° and 140°, respectively. In methanol the compounds 1 and 2 had absorption maxima at 360 and 370 nm respectively, and emission maxima at 494 and 539 nm. Experiments revealed varied fluorescence responses of the nucleosides to a panel of seventeen monovalent, divalent and trivalent metal ions in methanol. One or both of the nucleosides showed significant changes with ten of the metal ions. The most pronounced spectral changes for ligand-nucleoside 1 included red shifts in fluorescence (Au+, Au3+), strong quenching (Cu2+, Ni2+, Pt2+), and in substantial enhancements in emission intensity coupled with redshifts (Ag+, Cd2+, Zn2+). The greatest spectral changes for ligand-nucleoside 2 included a redshift in fluorescence (Ag+), a blueshift (Cd2+), strong quenching (Pd2+, Pt2+), and in substantial enhancements in emission intensity coupled with a blueshift (Zn2+). The compounds could be readily incorporated into oligodeoxynucleotides, where an initial study revealed that they retained sensitivity to metal ions in aqueous solution, and demonstrated possible cooperative sensing behavior with several ions. The two free nucleosides alone can act as differential sensors for at multiple metal ions, and they are potentially useful monomers for contributing metal ion sensing capability to DNAs. PMID:16669686

Kim, Su Jeong; Kool, Eric T.

2008-01-01

202

Layered metal sulfides: Exceptionally selective agents for radioactive strontium removal  

PubMed Central

In this article, we report the family of robust layered sulfides K2xMnxSn3-xS6 (x = 0.5–0.95) (KMS-1). These materials feature hexagonal [MnxSn3-xS6]2x? slabs of the CdI2 type and contain highly mobile K+ ions in their interlayer space that are easily exchangeable with other cations and particularly strontium. KMS-1 display outstanding preference for strontium ions in highly alkaline solutions containing extremely large excess of sodium cations as well as in acidic environment where most alternative adsorbents with oxygen ligands are nearly inactive. The implication of these results is that simple layered sulfides should be considered for the efficient remediation of certain nuclear wastes. PMID:18316731

Manos, Manolis J.; Ding, Nan; Kanatzidis, Mercouri G.

2008-01-01

203

Depth resolution improvement in secondary ion mass spectrometry analysis using metal cluster complex ion bombardment  

SciTech Connect

Secondary ion mass spectrometry analyses were carried out using a metal cluster complex ion of Ir{sub 4}(CO){sub 7}{sup +} as a primary ion beam. Depth resolution was evaluated as a function of primary ion species, energy, and incident angle. The depth resolution obtained using cluster ion bombardment was considerably better than that obtained by oxygen ion bombardment under the same experimental condition due to reduction of atomic mixing in the depth. The authors obtained a depth resolution of {approx}1 nm under 5 keV, 45 deg. condition. Depth resolution was degraded by ion-bombardment-induced surface roughness at 5 keV with higher incident angles.

Tomita, M.; Kinno, T.; Koike, M.; Tanaka, H.; Takeno, S.; Fujiwara, Y.; Kondou, K.; Teranishi, Y.; Nonaka, H.; Fujimoto, T.; Kurokawa, A.; Ichimura, S. [Corporate Research and Development Center, Toshiba Corporation, 8 Shinsugita-cho, Isogo-ku, Yokohama 235-8522 (Japan); National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 2, 1-1-1 Umezono, Tsukuba-shi, Ibaraki-ken 305-8568 (Japan)

2006-07-31

204

Uptake of Metal Ions by Rhizopus arrhizus Biomass  

PubMed Central

Rhizopus arrhizus biomass was found to absorb a variety of different metal cations and anions but did not absorb alkali metal ions. The amount of uptake of the cations was directly related to ionic radii of La3+, Mn2+, Cu2+, Zn2+, Cd2+, Ba2+, Hg2+, Pb2+, UO22+, and Ag+. The uptake of all the cations is consistent with absorption of the metals by sites in the biomass containing phosphate, carboxylate, and other functional groups. The uptake of the molybdate and vanadate anions was strongly pH dependent, and it is proposed that the uptake mechanism involves electrostatic attraction to positively charged functional groups. PMID:16346521

Tobin, J. M.; Cooper, D. G.; Neufeld, R. J.

1984-01-01

205

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

206

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

207

Electropositive bivalent metallic ion unsaturated polyester complexed polymer concrete  

DOEpatents

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

Sugama, Toshifumi (Mastic Beach, NY); Kukacka, Lawrence E. (Port Jefferson, NY); Horn, William H. (Brookhaven, NY)

1985-01-01

208

Electropositive bivalent metallic ion unsaturated polyester complexed polymer concrete  

DOEpatents

Quick setting polymer concrete compositions 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.

1981-11-04

209

Selective titrations of metal ions in the micromolar range  

Microsoft Academic Search

Summary An outline is given of the factors governing the complexometric titration of metal ions at low concentration. Apart from the limit of determination, special attention has been given to the selectivity of the determinations. The influence of the chemical reaction and of the method of indication has been discussed.

G. den Boef

1978-01-01

210

Broad-beam, high current, metal ion implantation facility  

SciTech Connect

We have developed a high current metal ion implantation facility with which high current beams of virtually all the solid metals of the Periodic Table can be produced. The facility makes use of a metal vapor vacuum arc ion source which is operated in a pulsed mode, with pulse width 0.25 ms and repetition rate up to 100 pps. Beam extraction voltage is up to 100 kV, corresponding to an ion energy of up to several hundred keV because of the ion charge state multiplicity; beam current is up to several Amperes peak and around 10 mA time averaged delivered onto target. Implantation is done in a broad-beam mode, with a direct line-of-sight from ion source to target. Here we describe the facility and some of the implants that have been carried out using it, including the seeding' of silicon wafers prior to CVD with titanium, palladium or tungsten, the formation of buried iridium silicide layers, and actinide (uranium and thorium) doping of III-V compounds. 16 refs., 6 figs.

Brown, I.G.; Dickinson, M.R.; Galvin, J.E.; Godechot, X.; MacGill, R.A.

1990-07-01

211

Commisioning of the windowless gas target at ORNL's Holifield Radioactive Ion Beam Facility  

NASA Astrophysics Data System (ADS)

Direct measurements of many astrophysically relevant proton-induced reactions using radioactive ion beams require the use of hydrogen targets. The use of solid polypropylene targets is not always advantageous because of the large energy loss in the solid target and the existence of contaminant reactions on the carbon. At the Holifield Radioactive Ion Beam Facility, we have commissioned a windowless hydrogen gas target to be used in conjunction with the Daresbury Recoil Separator. The apparatus is connected to the beamline via 8 differential pumping stages (4 located upstream of the target and 4 downstream) and has a central chamber that can be filled with hydrogen gas at pressures up to 8 Torr, while keeping good vacuum in the beamline. The setup and characterization of the target will be discussed along with its utilization in a number of measurements such as ^17F(p,?)^18Ne and ^7Be(p,?)^8B.

Moazen, B. H.; Blackmon, J. C.; Bardayan, D. W.; Domizioli, C. P.; Fitzgerald, R.; Greife, U.; Livesay, R. J.; Smith, M. S.

2009-05-01

212

Charge state breeding for the acceleration of radioactive ions at TRIUMF.  

PubMed

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 (80)Rb(14+) was successfully created from (80)Rb(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 (124)Cs(20+) has been obtained. PMID:20192401

Ames, F; Baartman, R; Bricault, P; Jayamanna, K; Lamy, T; McDonald, M

2010-02-01

213

Development of a 1+/N+ setup for the production of multicharged radioactive alkali ions in SPIRAL  

SciTech Connect

In the framework of the production of radioactive ion beams by the isotope separator online method, a new system has been developed at GANIL/SPIRAL I to produce multicharged alkali ions. The principle, referred to as the ''direct 1+/N+ method,'' consists of a surface ionization source associated with a multicharged electron-cyclotron-resonance ion source without an intermediate mass separator. This new system has been tested online using a {sup 48}Ca primary beam at 60.3 A MeV. The experimental evidence of the direct 1+/N+ process has been obtained for a potential difference between the two sources of 11 V and with a 1+/N+ charge breeding efficiency of 0.04% for {sup 47}K{sup 5+}. This value is significantly lower than the value of 6% obtained for stable K ions with the standard 1+/N+ method. A possible explanation is given in the text.

Eleon, C.; Gaubert, G.; Jardin, P.; Saint-Laurent, M.-G.; Alcantara, J.; Alves Conde, R.; Barue, C.; Boilley, D.; Cornell, J. C.; Delahaye, P.; Dubois, M.; Jacquot, B.; Leherissier, P.; Leroy, R.; Lhersonneau, G.; Marie-Jeanne, M.; Maunoury, L.; Pacquet, J.-Y.; Pellemoine, F.; Pierret, C. [GANIL CEA/DSN-CNRS/IN2P3, Bd. H. Becquerel, BP 55027, 14076 Caen Cedex 5 (France); CERN ISOLDE, 1211 GENEVA 23 (Switzerland); GANIL CEA/DSN-CNRS/IN2P3, Bd. H. Becquerel, BP 55027, 14076 Caen Cedex 5 (France); CERN ISOLDE, 1211 GENEVA 23 (Switzerland); CIRIL, Bd. H. Becquerel, BP 5133, 14070 Caen Cedex 5 (France); GANIL CEA/DSN-CNRS/IN2P3, Bd. H. Becquerel, BP 55027, 14076 Caen Cedex 5 (France); CIRIL, Bd. H. Becquerel, BP 5133, 14070 Caen Cedex 5 (France); GANIL CEA/DSN-CNRS/IN2P3, Bd. H. Becquerel, BP 55027, 14076 Caen Cedex 5 (France)] (and others)

2008-02-15

214

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

215

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

216

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

217

Rotating target facility for in-flight radioactive ion beam production using a recoil mass spectrometer  

Microsoft Academic Search

A facility has been developed for production of light radioactive ion beams (RIBs) using (p,n), (d,n) reactions in inverse kinematics using an in-flight technique. Primary beams from the 15UD Pelletron accelerator are used on a hydrogenous target and the RIB is separated and re-focused to a secondary target position using the existing recoil mass spectrometer (RMS), HIRA operated in a

T. Varughese; J. J. Das; N. Madhavan; P. Sugathan; P. V. Madhusudhana Rao; A. Jhingan; S. Nath; A. K. Sinha; J. Zacharias

2004-01-01

218

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

2013-06-01

219

Selective adsorption and ion exchange of metal cations and anions with silico-titanates and layered titanates  

SciTech Connect

Metal ions may be removed from aqueous wastes from metal processing plants and from refineries. They may also be used in concentrating radioactive elements found in dilute, aqueous, nuclear wastes. A new series of silico-titanates and alkali titanates are shown to have specific selectivity for cations of lead, mercury, and cadmium and the dichromate anion in solutions with low and high pH. Furthermore, one particular silico-titanate, TAM-5, was found to be highly selective for Cs[sup +] and Sr[sup 2+] in solutions of 5.7 M Na[sup +] and 0.6 M Oh[sup [minus

Anthony, R.G.; Philip, C.V. (Texas A and M Univ., College Station, TX (United States). Dept. of Chemical Engineering); Dosch, R.G. (Sandia National Labs., Albuquerque, NM (United States))

1993-01-01

220

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

221

The Structure of the Metal Transporter Tp34 and its Affinity for Divalent Metal Ions  

NASA Astrophysics Data System (ADS)

Tp34 is periplasmic membrane protein of the nonculitvatable spirochete Treponema pallidum, the pathogen of syphillis. It was proposed that Tp34 is a divalent metal transporter, but the identity of the preferred metal ion(s) was unclear. In this study we investigated the ability of divalent metal ions to induce rTp34 dimerization using hydrodynamic techniques and determine the crystal structure of metal bound forms. Using analytical ultracentrifugation sedimentation velocity experiments, we determined that cobalt is superior to nickel at inducing the dimerization of rTp34. rTp34 was crystallized and selected crystals were incubated at a pH 7.5 with CuSO4 and NiSO4. Diffraction experiments were conducted and the processed electron density maps showed that copper was bound to the major metal binding site as well as to three additional minor binding sites. By contrast nickel was only bound to the major metal binding site in one monomer and to three additional minor sites. These results along with previous findings support evidence of Tp34 being involved with metal transport and/or iron utilization.

Knutsen, Gregory; Deka, Ranjit; Brautigam, Chad; Tomchick, Diana; Machius, Mischa; Norgard, Michael

2007-10-01

222

Metal content of metallo-?-lactamase L1 is determined by the bioavailability of metal ions†  

PubMed Central

In an effort to probe whether the metal content of metallo-?-lactamase L1 is affected by metal ion bioavailability, L1 was over-expressed as mature protein (M-L1) and full-length (FL-L1) analogs, and the analogs were characterized with metal analyses, kinetics, and EPR spectroscopy. FL-L1, containing the putative leader sequence, was localized in the periplasm of E. coli and shown to bind Zn(II) preferentially. The metal content of FL-L1 could be altered if the enzyme was over-expressed in minimal medium containing Fe and Mn, and surprisingly, an Fe-binding analog was obtained. On the other hand, M-L1, lacking the putative leader sequence, was localized in the cytoplasm of E. coli and shown to bind various amounts of Fe and Zn(II), and like FL-L1, the metal content of the resulting enzyme could be affected by the amount of metal ions in the growth medium. L1 was refolded in the presence of Fe, and a dinuclear Fe-containing analog of L1 was obtained, although this analog is catalytically-inactive. EPR spectra demonstrate the presence of an antiferromagnetically-coupled Fe(III)Fe(II) center in Fe-containing L1 and suggests the presence of a Fe(III)Zn(II) center in M-L1. Metal analyses on the cytoplasmic and periplasmic fractions of E. coli showed that the concentration of metal ions in the periplasm is not tightly controlled and increases as the concentration of metal ions in the growth medium increases. In contrast, the concentration of Zn(II) in the cytoplasm is tightly-controlled while that of Fe is less so. PMID:18597493

Hu, Zhenxin; Gunasekera, Thusitha S; Spadafora, Lauren; Bennett, Brian; Crowder, Michael W.

2009-01-01

223

The influence of transition metal ions on collagen mineralization.  

PubMed

The ions in body fluid play an important role in bone formation besides being a synthesizing material. Transition metal ions Co(2+), Ni(2+), Zn(2+), Fe(3+), Mn(2+), Cu(2+), Cd(2+) and Hg(2+) doped hydroxyapatite (HAP)/collagen composites were synthesized successfully in the presence of collagen traces at mild acidic pH for the first time. However, the amount of doped Hg(2+) and Cd(2+) was relatively low. Meanwhile, through soaking the collagen sponge as a template in simulated body fluid (SBF) which contains different transition metal ions (Mn(2+), Cu(2+), Ni(2+), Co(2+), Cd(2+), Hg(2+)), bone-like HAP/collagen composites were synthesized. Hg(2+) had a certain inhibitory effect on the formation of HAP crystals on the surface of the collagen sponge while Co(2+) can promote the formation of HAP on the collagen sponge. For both HAP/collagen composites and HAP/collagen sponge, it was found that transition metal ions Mn(2+) had a significant effect on the morphology of HAP particles and could induce to form floc-like HAP particle aggregates. PMID:23498275

Jia, Mingfen; Hong, Yuanping; Duan, Shuyuan; Liu, Yongjun; Yuan, Bo; Jiang, Fengzhi

2013-05-01

224

Peptide immobilisation on porous silicon surface for metal ions detection.  

PubMed

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. PMID:21711937

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

2011-01-01

225

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 new kind of high current metal ion source in which the ion beam is extracted from a metal vapor vacuum arc plasma has been used to obtain the spectra of multiply charged ions produced within the cathode spots. The cathode materials used and the species reportetd on here are: C, Mg, Al, Si, Ti, Cr, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, Rh, Pd, Ag, In, Sn, Gd, Ho, Ta, W, Pt, Au, Pb, Th, and U; the arc current was 200 A for all measurements. Charge state spectra were measured using a time-of-flight method. The arc voltage was also measured. In this paper we report on the measured charge state distributions and arc voltages and compare the distributions with the predictions of a theory in which ionization occurs in the cathode spots via stepwise ionization by electron impact. 64 refs., 10 figs., 3 tabs.

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

1987-09-01

226

Transition Metal Ions: Charge Carriers that Mediate the Electron Capture Dissociation Pathways of Peptides  

NASA Astrophysics Data System (ADS)

Electron capture dissociation (ECD) of model peptides adducted with first row divalent transition metal ions, including Mn2+, Fe2+, Co2+, Ni2+, Cu2+, and Zn2+, were investigated. Model peptides with general sequence of ZGGGXGGGZ were used as probes to unveil the ECD mechanism of metalated peptides, where X is either V or W; and Z is either R or N. Peptides metalated with different divalent transition metal ions were found to generate different ECD tandem mass spectra. ECD spectra of peptides metalated by Mn2+ and Zn2+ were similar to those generated by ECD of peptides adducted with alkaline earth metal ions. Series of c-/ z-type fragment ions with and without metal ions were observed. ECD of Fe2+, Co2+, and Ni2+ adducted peptides yielded abundant metalated a-/ y-type fragment ions; whereas ECD of Cu2+ adducted peptides generated predominantly metalated b-/ y-type fragment ions. From the present experimental results, it was postulated that electronic configuration of metal ions is an important factor in determining the ECD behavior of the metalated peptides. Due presumably to the stability of the electronic configuration, metal ions with fully-filled (i.e., Zn2+) and half filled (i.e., Mn2+) d-orbitals might not capture the incoming electron. Dissociation of the metal ions adducted peptides would proceed through the usual ECD channel(s) via "hot-hydrogen" or "superbase" intermediates, to form series of c-/z •- fragments. For other transition metal ions studied, reduction of the metal ions might occur preferentially. The energy liberated by the metal ion reduction would provide enough internal energy to generate the "slow-heating" type of fragment ions, i.e., metalated a-/y- fragments and metalated b-/y- fragments.

Chen, Xiangfeng; Fung, Yi Man Eva; Chan, Wai Yi Kelly; Wong, Pui Shuen; Yeung, Hoi Sze; Chan, T.-W. Dominic

2011-12-01

227

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

228

Reactive Ion Etching of Transition-Metal Alloys  

NASA Astrophysics Data System (ADS)

For production of advanced spin-electronic devices, such as a magnetic random access memory with the higher-density memory cell, a reactive ion etching (RIE) process of transition metal alloys is the indispensable component of development, while no transition-metal compounds with the relatively high vapor pressure have been founded so far. Here, we show the RIE process of a NiFe thin film by using CH4:O2:NH3 discharge. The RIE process was designed by ab initio calculations, and the present result is the first successful demonstration of the chemical effect in the RIE process for transition-metal alloys. The relative etching ratio of NiFe against Ti as the metal mask was decreased by substituting CH4 with CHF3.

Akinaga, Hiro; Takano, Fumiyoshi; Matsumoto, Shigeno; Diño, Wilson A. T.

229

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

230

Silica gel modified with Eriochrome Blue SE as a sorbent in trace analysis for metal ions  

Microsoft Academic Search

The sorption of 14 metal ions on silica gel impregnated with a mixture of Aliquat 336 and Eriochrome Blue SE was investigated. It was found that the sorption behaviour depends upon the species and the pH of the loading solution. Alkali metal ions were not retained under any of the investigated conditions. The retained metal ions can be eluted with

Ryszard Kocjan; Ryszard ?wieboda

1996-01-01

231

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

232

Kinetic and mechanistic aspects of metal ion catalysis in cerium(IV) oxidation  

Microsoft Academic Search

This review discusses the kinetic aspects of different metal ion catalysis in Ce(IV) oxidation of different types of organic and inorganic substrates in aqueous acid media. The reactions have been categorised with the metal ions acting as the catalysts. The nature of mechanism of catalysis in Ce(IV) oxidation depends on the nature of substrate for a particular metal ion catalyst

Asim K. Das

2001-01-01

233

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

234

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

235

Metal ion leaching from contaminated soils: Model development  

SciTech Connect

A mathematical model is developed for metal leaching from contaminated soils subjected to acid extraction in a batch reactor. The model considers transport by pore diffusion and film transfer, leaching of metal bound to reversible and irreversible phases, and metal complexation by ions in solution. As currently developed, the model is semiempirical, with the primary objective of exploring the relative significance of chemical kinetics and diffusional transport under acidic leaching conditions. Simulation results and sensitivity analyses show that leaching kinetics vary according to the metal binding mechanism and location with a soil particle. The effects of pH, pore diffusion, film transfer, chemical reaction rate, particle size, and initial metal distribution are examined using parameter estimates derived from experimental data for a hazardous-waste-site soil contaminated with lead. Depending on leaching conditions, diffusion, reaction, or both may control metal leaching for time-scales of interest in soil washing. Both the distribution of contaminant metal between the reversibly and irreversibly sorbed fractions and the initial spatial distribution within the soil particle are important in determining leaching behavior.

Ganguly, C.; Rabideau, A.J.; Benschoten, J.E. Van [Univ. of New York, Buffalo, NY (United States). Dept. of Civil Engineering; Matsumoto, M.R. [Univ. of California, Riverside, CA (United States). College of Engineering

1998-03-01

236

Stability constants of HBED with various metal ions  

E-print Network

. A combination of potentiometric titration and spectrophotometric titration at varying high -log[H]'s was used to determine the protonation constants for HBED. Potentiometric titrations of 1:1 metal:HBED solutions were used to obtain stability... The importance for the determination of the stability constants for the ligand N, N'-bis(2-hydroxybenzyl)? ethylenediamine-N, N'-diacetic acid (HBED) with various metal ions is that it has the potential to form highly stable complexes with ~ BGa(III) In...

Long, Gregory Neal

2012-06-07

237

Muon Tomography as a Tool to Detect Radioactive Source Shielding in Scrap Metal Containers  

NASA Astrophysics Data System (ADS)

Muon tomography was recently proposed as a tool to inspect large volumes with the purpose of recognizing high density materials immersed in lower density matrices. The MU-STEEL European project (RFCS-CT-2010-000033) studied the application of such a technique to detect radioactive source shielding in truck containers filled with scrap metals entering steel mill foundries. A description of the muon tomography technique, of the MU-STEEL project and of the obtained results will be presented.

Bonomi, G.; Cambiaghi, D.; Dassa, L.; Donzella, A.; Subieta, M.; Villa, V.; Zenoni, A.; Furlan, M.; Rigoni, A.; Vanini, S.; Viesti, G.; Zumerle, G.; Benettoni, M.; Checchia, P.; Gonella, F.; Pegoraro, M.; Zanuttigh, P.; Calvagno, G.; Calvini, P.; Squarcia, S.

2014-02-01

238

Evaluation of the electrorefining technique for the processing of radioactive scrap metals  

SciTech Connect

This report presents the results of a literature study performed to identify applications of the electrorefining technique to the decontamination of radioactively-contaminated scrap metal (RSM). Upon the completion of the literature search and the review of numerous references, it was concluded that there were applications of this technique that were appropriate for the decontamination of some types of RSM, especially when the desired product is a pure elemental metal of high purity. It was also concluded that this technique was not well-suited for the decontamination of RSM stainless steels and other alloys, when it was desired that the metallurgical characteristics of the alloy be present in the decontaminated product.

Kessinger, G.F.

1993-10-01

239

Metal-assisted SIMS and cluster ion bombardment for ion yield enhancement  

NASA Astrophysics Data System (ADS)

In addition to structural information, a detailed knowledge of the local chemical environment proves to be of ever greater importance, for example for the development of new types of materials as well as for specific modifications of surfaces and interfaces in multiple fields of materials science or various biomedical and chemical applications. But the ongoing miniaturization and therefore reduction of the amount of material available for analysis constitute a challenge to the detection limits of analytical methods. In the case of time-of-flight secondary ion mass spectrometry (TOF-SIMS), several methods of secondary ion yield enhancement have been proposed. This paper focuses on the investigation of the effects of two of these methods, metal-assisted SIMS and polyatomic primary ion bombardment. For this purpose, thicker layers of polystyrene (PS), both pristine and metallized with different amounts of gold, were analyzed using monoatomic (Ar +, Ga +, Xe +, Bi +) and polyatomic (SF 5+, Bi 3+, C 60+) primary ions. It was found that polyatomic ions generally induce a significant increase of the secondary ion yield. On the other hand, with gold deposition, a yield enhancement can only be detected for monoatomic ion bombardment.

Heile, A.; Lipinsky, D.; Wehbe, N.; Delcorte, A.; Bertrand, P.; Felten, A.; Houssiau, L.; Pireaux, J.-J.; De Mondt, R.; Van Vaeck, L.; Arlinghaus, H. F.

2008-12-01

240

Commissioning of the Daresbury Recoil Separator for nuclear astrophysics measurements 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 and X-ray bursts. The physics motivation and plans for the first measurements with radioactive beams are described, and details of the new DRS experimental equipment and preliminary results from the first commissioning experiments with stable beams are given.

Smith, M.S.; Blackmon, J.C.; Koehler, P.E. [Oak Ridge National Lab., TN (United States). Physics Div.] [and others

1997-12-01

241

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...

242

Recoil separators for radiative capture using radioactive ion beams. Recent advances and detection techniques  

NASA Astrophysics Data System (ADS)

Radiative capture reactions involving the fusion of hydrogen or helium are ubiquitous in the stellar history of the universe, and are some of the most important reactions in the processes that govern nucleosynthesis and energy generation in both static and explosive scenarios. However, radiative capture reactions pose some of the most difficult experimental challenges due to extremely small cross sections. With the advent of recoil separators and techniques in inverse kinematics, it is now possible to measure radiative capture reactions on very short-lived radioactive nuclei, and in the presence of high experimental backgrounds. In this paper we review the experimental needs for making measurements of astrophysical importance on radiative capture reactions. We also review some of the important historical advances in the field of recoil separators as well as describe current techniques and performance milestones, including descriptions of some of the separators most recently working at radioactive ion beam facilities, such as DRAGON at TRIUMF and the DRS at the Holifield Radioactive Ion Beam Facility. We will also summarize some of the scientific highlight measurements at the RIB facilities.

Ruiz, Chris; Greife, Uwe; Hager, Ulrike

2014-06-01

243

Interactions of metal ions with ? synuclein and amyloid ? peptides  

NASA Astrophysics Data System (ADS)

Amyloid ? (A?) and alfa synuclein (?S) share the ability to selectively bind copper ions (Cu(II) and Cu(I)). During the last decade large efforts have been directed to fully characterize Cu(II) binding domains in A? and ?S. On the other hand, the corresponding Cu(I) sites have been less considered. In this study we have analyzed Cu(I) interactions with peptides derived from A? and ?S, by means of CD and NMR spectroscopy. Beyond Cu(I), we have also used Ag(I) as a probe. By monitoring the metal induced effects on ?S and A? systems, the Cu(I)/Ag(I) binding domains have been identified. The corresponding protein structural rearrangements induced by the metal ions have been investigated as well. The Cu(I) coordination spheres are discussed with a particular emphasis to the role played by Met and His residues.

Valensin, Daniela; Kozlowski, Henryk; Tessari, Isabella; Dell'Acqua, Simone; Bubacco, Luigi; Casella, Luigi; Gaggelli, Elena; Valensin, Gianni

2014-10-01

244

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

245

Traitement par fusion des dechets metalliques contamines faible activite. (Fusion process for metallic wastes slightly contaminated by radioactive substances).  

National Technical Information Service (NTIS)

To ameliorate the management of metallic wastes lightly contaminated by radioactive substances and coming from nuclear installations dismantling, the Radiation Protection Service of Saclay has undertaken the study of fusion process for these wastes. After...

C. Doucet

1988-01-01

246

Extracellular Ribonuclease Production by Rhizopus stolonifer : Influence of Metal Ions  

Microsoft Academic Search

.   A strain of Rhizopus stolonifer produced high levels of extracellular ribonuclease (RNase) when grown on YPG (yeast extract, peptone, glucose) medium. Influence\\u000a of various medium components on the production of extracellular RNase activity showed that divalent metal ions had a marked\\u000a effect on growth and enzyme production. Maximum enzyme activity (3000 U\\/ml) was obtained in 5 days when the

Rohini Chacko; Mukund Deshpande; Vepatu Shankar

1996-01-01

247

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

248

Metal ion accumulation by immobilised cells of Brevibacterium sp  

Microsoft Academic Search

  This paper explores the use of an experimental system based on polyacrylamide-entrapped cells of Brevibacterium sp strain PBZ for the removal of metal ions from solutions. Experiments were performed in columns filled with the immobilised\\u000a cells and challenged with influents containing 20?mg L?1 of lead and 10?mg L?1 of cadmium. The cells were able to accumulate lead (about 40?mg g?1

D Di Simine; C Finoli; A Vecchio; V Andreoni

1998-01-01

249

Interaction of heavy metal ions with ammonium humates  

SciTech Connect

Sorption properties of ammonium humates with respect to Fe(III), Cu(II), Al(III), Ni(II), Pb(II), and Zn(II) are studied. The effect of the metal ion concentration on the ammonium humate consumption is examined and the corresponding dependences are analyzed using regression equations. The IR spectra of brown coal humic acids, ammonium humates, as well as Fe, Cu, Ni, Zn, Pb, and Al humates are presented.

Budaeva, A.D.; Zoltoev, E.V.; Tikhova, V.D.; Bodoev, N.V. [Russian Academy for Science, Buryatiya (Russian Federation)

2006-06-15

250

Precious metal catalysts with oxygen-ion conducting support  

Microsoft Academic Search

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

P. S. Ganguli; S. Sundaresan

1993-01-01

251

Measurement of binding constants of poly(ethylenimine) with metal ions and metal chelates in aqueous media by ultrafiltration  

SciTech Connect

Equilibrium constants for the binding of poly(ethylenimine) (PEI) with metal ions and metal chelates of ethylenediaminetetraacetic acid and nitrilotriacetic acid in the aqueous sulfate solutions were determined by batch ultrafiltration (UF) in the pH range of 3.0--3.8. The average coordination number of PEI groups interacting with one metal ion and metal chelate was also obtained by varying the initial concentration ratio of PEI to metal ion. A simple chemical equilibrium model proposed in this work enabled the authors to satisfactorily predict the rejection coefficient of UF of metal ions and metal chelates in the presence of PEI. Also, the effect of the formation of soluble hydroxy complexes of metal chelates on their retention was emphasized.

Juang, R.S.; Chen, M.N. [Yuan-Ze Inst. of Technology, Taoyuan (Taiwan, Province of China). Dept. of Chemical Engineering] [Yuan-Ze Inst. of Technology, Taoyuan (Taiwan, Province of China). Dept. of Chemical Engineering

1996-06-01

252

Note: An ion source for alkali metal implantation beneath graphene and hexagonal boron nitride monolayers on transition metals  

SciTech Connect

The construction of an alkali-metal ion source is presented. It allows the acceleration of rubidium ions to an energy that enables the penetration through monolayers of graphene and hexagonal boron nitride. Rb atoms are sublimated from an alkali-metal dispenser. The ionization is obtained by surface ionization and desorption from a hot high work function surface. The ion current is easily controlled by the temperature of ionizer. Scanning Tunneling Microscopy measurements confirm ion implantation.

Lima, L. H. de [Instituto de Física “Gleb Wataghin”, Universidade Estadual de Campinas, 13083-859, Campinas, SP (Brazil)] [Instituto de Física “Gleb Wataghin”, Universidade Estadual de Campinas, 13083-859, Campinas, SP (Brazil); Cun, H. Y.; Hemmi, A.; Kälin, T.; Greber, T. [Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich (Switzerland)] [Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich (Switzerland)

2013-12-15

253

DOI: 10.1002/chem.201002135 High Gas Sorption and Metal-Ion Exchange of Microporous MetalOrganic  

E-print Network

DOI: 10.1002/chem.201002135 High Gas Sorption and Metal-Ion Exchange of Microporous Metal of their potential ap- plications in gas storage, gas separation, catalysis, and fabri- cation of nanoparticles.[1 by the creation of open metal sites, through syn- thesis of catenated frameworks, and by imbedding metal

Paik Suh, Myunghyun

254

Adsorption of heavy metal ion from aqueous single metal solution by chemically modified sugarcane bagasse  

Microsoft Academic Search

This work describes the preparation of new chelating materials derived from sugarcane bagasse for adsorption of heavy metal ions in aqueous solution. The first part of this report deals with the chemical modification of sugarcane bagasse with succinic anhydride. The carboxylic acid functions introduced into the material were used to anchor polyamines, which resulted in two yet unpublished modified sugarcane

Osvaldo Karnitz; Leandro Vinicius Alves Gurgel; Júlio César Perin de Melo; Vagner Roberto Botaro; Tânia Márcia Sacramento Melo; Rossimiriam Pereira de Freitas Gil; Laurent Frédéric Gil

2007-01-01

255

Search for new physics with neutrinos at Radioactive Ion Beam facilities  

E-print Network

We propose applications of Radioactive Ion Beam facilities to investigate physics beyond the Standard Model. In particular, we focus on the possible measurement of coherent neutrino-nucleus scattering and on a search for sterile neutrinos, by means of a low energy beta-beam with a Lorentz boost factor $\\gamma \\approx 1$. In the considered setup the collected radioactive ions are sent inside a 4$\\pi$ detector. For the first application we provide the number of events associated with neutrino-nucleus coherent scattering, when the detector is filled in with a noble liquid. For the sterile search we consider that the spherical detector is filled in 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 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.

Catalina Espinoza; Rimantas Lazauskas; Cristina Volpe

2012-03-05

256

Near-barrier reactions with radioactive ion beams at the ReA3 facility  

NASA Astrophysics Data System (ADS)

The new ReA3 re-accelerated beam facility at the National Superconducting Cyclotron Laboratory (NSCL) will provide high quality radioactive ion beams (RIBs), produced from fast fragmentation reactions, at energies around the Coulomb barrier. These radioactive isotopes can have exotic properties such as neutron/proton skins, halos, or unexpected changes in their shell structure. ReA3 will allow us to explore how these exotic properties manifest themselves in low-energy reactions. In particular, heavy-ion fusion induced with medium mass RIBs remains almost completely unexplored as only three fusion reactions using RIBs, between fluorine (Z = 9) and tin (Z = 50), have ever been measured. A new research program focused on the study of heavy-ion fusion reactions is being developed to take advantage of the world-unique RIBs offered by the ReA3 facility. Along with an overview of the ReA3 facility, details about three devices being developed for exploration of fusion reactions induced by RIBs will be presented.

Kohley, Z.

2013-12-01

257

Acetabular bone density and metal ions after metal-on-metal versus metal-on-polyethylene total hip arthroplasty; short-term results.  

PubMed

Information on periprosthetic acetabular bone density is lacking for metal-on-metal total hip arthroplasties. These bearings use cobalt-chromium instead of titanium acetabular components, which could lead to stress shielding and hence periprosthetic bone loss. Cobalt and chromium ions have detrimental effects on bone. It is unknown whether serum metal ion levels affect bone density clinically. We compared cementless large femoral head (mean 48 mm) metal-on-metal total hip arthroplasties (M2a-Magnum, Biomet) to cementless 28 mm metal-on-polyethylene total hip arthroplasties (Mallory-Head, Biomet) in a randomised clinical trial. We evaluated periprosthetic acetabular bone density and serum metal ion levels at 1 year postoperatively. Acetabular bone density was analyzed with dual energy x-ray absorptiometry in four horizontal regions of interest in 70 patients. After one year, acetabular bone density decreased (-3.5% to -7.8%) in three of four regions of interest in metal-on-polyethylene patients, but was retained in metal-on-metal patients. Bone density preservation was most pronounced superior to the metal-on-metal cup (+1% versus -3.7%). Serum cobalt, chromium and titanium ion levels were not related to bone density, nor to acetabular inclination or femoral head size. Oxford and Harris hip scores were similar in both groups. Contrary to our hypothesis, acetabular bone density was retained with metal-on-metal total hip arthroplasty, compared to metal-on-polyethylene arthroplasty. Bone preservation was most pronounced in the area superior to the cup. This could be a benefit during future revision surgery. PMID:24186673

Zijlstra, Wierd P; van der Veen, Hugo C; van den Akker-Scheek, Inge; Zee, Mark J M; Bulstra, Sjoerd K; van Raay, Jos J A M

2014-01-01

258

Stabilization of Metal-Loaded Ion-Exchange Resin with a Porous Silica Supporter Through Thermal Treatment  

SciTech Connect

A new ion exchanger with porous silica as a supporting material and diphosphonic acid as a functional chelating group has been developed at ANL for the effective removal of transition metals and actinide ions from very acidic radioactive liquid wastes. The applicability of this resin for the treatment of low- and/or intermediate-level aqueous waste from nuclear power plants (NPP) has not been reported in scientific literature, but is under study now in Korea. The major radioisotopes in NPP radioactive liquid waste are Cs and Co in neutral pH ranges. This study on the thermal stabilization of metal-loaded waste resin has been carried out in parallel with the sorption experiment. Thermal treatment of metal (Co, Cs or U) loaded resin was accomplished to see the possibility of enhancing the safety and stability of the final product during transportation and disposal. In this paper, characteristics of the metal-loaded resins before and after heat treatment at three different thermal conditions were investigated and compared with each other to see the effectiveness of the thermal treatment method.

Kim, I-T. Park, H-S.; Yoo, J-H.; Kim, J-H.

2003-02-25

259

UPTAKE OF METAL IONS BY A NEW CHELATING ION-EXCHANGE RESIN. PART 2: ACID DEPENDENCIES OF TRANSITION AND POST-TRANSITION METAL IONS  

Microsoft Academic Search

Diphonixis a new dual-mechanism polyfunctional resin containing sulfonic and gem-diphosphonic acid groups. In Part 1 of this series the effectiveness of Diphonix in removing actinide ions from very acidic solutions was demonstrated. In this paper we report on the uptake of various transition and post-transition metal ions with Diphonix and two other resins for comparison. The results show that Diphonix

R. Chiarizia; E. P. Horwitz; R. C. Gatrone; S. D. Alexandratos; A. Q. Trochimczuk; D. W. Crick

1993-01-01

260

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

261

No association between serum metal ions and implant fixation in large-head metal-on-metal total hip arthroplasty  

PubMed Central

Background The mechanism of failure of metal-on-metal (MoM) total hip arthroplasty (THA) has been related to a high rate of metal wear debris, which is partly generated from the head-trunnion interface. However, it is not known whether implant fixation is affected by metal wear debris. Patients and methods 49 cases of MoM THA in 41 patients (10 women) with a mean age of 52 (28–68) years were followed with stereoradiographs after surgery and at 1, 2, and 5 years to analyze implant migration by radiostereometric analysis (RSA). Patients also participated in a 5- to 7-year follow-up with measurement of serum metal ions, questionnaires (Oxford hip score (OHS) and Harris hip score (HHS)), and measurement of cup and stem positions and systemic bone mineral density. Results At 1–2 years, mean total translation (TT) was 0.04 mm (95% CI: –0.07 to 0.14; p = 0.5) for the stems; at 2–5 years, mean TT was 0.13 mm (95% CI: –0.25 to –0.01; p = 0.03), but within the precision limit of the method. For the cups, there was no statistically significant TT or total rotation (TR) at 1–2 and 2–5 years. At 2–5 years, we found 4 cups and 5 stems with TT migrations exceeding the precision limit of the method. There was an association between cup migration and total OHS < 40 (4 patients, 4 hips; p = 0.04), but there were no statistically significant associations between cup or stem migration and T-scores < –1 (n = 10), cup and stem positions, or elevated serum metal ion levels (> 7µg/L (4 patients, 6 hips)). Interpretation Most cups and stems were well-fixed at 1–5 years. However, at 2–5 years, 4 cups and 5 stems had TT migrations above the precision limits, but these patients had serum metal ion levels similar to those of patients without measurable migrations, and they were pain-free. Patients with serum metal ion levels > 7 µg/L had migrations similar to those in patients with serum metal ion levels < 7 µg/L. Metal wear debris does not appear to influence the fixation of hip components in large-head MoM articulations at medium-term follow-up. PMID:24847790

S?balle, Kjeld; Jakobsen, Stig Storgaard; Lorenzen, Nina Dyrberg; Mechlenburg, Inger; Stilling, Maiken

2014-01-01

262

Cesium Ion Uptake by Moss (Hypnum cupressiforme)  

Microsoft Academic Search

Lower land mosses uptake water and minerals from the atmosphere. They can collect metals polluting the air and radioactive fallout elements so they can be suitable for monitoring of these substances. Cesium ion uptake by Hypnum cupressiforme is studied by a radioactive tracer, Cs. The quantity of cesium ion in different cellular locations and the capacity of ion uptake is

N. M. Nagy; J. Kónya

1991-01-01

263

The electron-transfer based interaction between transition metal ions and photoluminescent graphene quantum dots (GQDs): a platform for metal ion sensing.  

PubMed

The electron-transfer based quenching effect of commonly encountered transition metal ions on the photoluminescence of grapheme quantum dots (GQDs) was for the first time investigated, and was found to be associated with electron configuration of the individual metal ion. Ethylene diamine tetraacetic acid (EDTA), the metal ion chelator, can competitively interact with metal ions to recover the quenched photoluminescence of GQDs. Basically, metal ions with empty or completely filled d orbits could not quench the photoluminescence of GQDs, but this quenching effect was observed for the metal ions with partly filled d orbits. Based on the quenching-recovering strategy, a simple optical metal sensing platform was established by taking Ni(2+) as an example. Using the nickel ion-specific chelating reagent, dimethylglyoxime (DMG), to replace EDTA, a detection limit of 4.1 ?M was obtained in standard solution. This proposed strategy does not need further functionalization of GQDs, facilitating the application for simple, fast and cost-effective screening of metal ions. PMID:24209324

Huang, Hongduan; Liao, Lei; Xu, Xiao; Zou, Mingjian; Liu, Feng; Li, Na

2013-12-15

264

Production of spin-polarized radioactive ion beams via projectile fragmentation reaction  

SciTech Connect

Spin-polarized radioactive ion beams are produced in the projectile fragmentation reaction induced by intermediate-energy heavy ion beams. The degree of spin polarization shows characteristic dependence on the outgoing momentum of the projectile fragment in the magnitude around 1{approx}10%. The qualitative behavior is well described by the kinematical model of the fragmentation process. Recently, we have successfully produced spin-polarized beams of aluminum isotopes in the mass A{approx}30 region via the fragmentation of 95 MeV/u {sup 40}Ar projectiles. The magnetic moments of {sup 30}Al and {sup 32}Al and the electric quadrupole moments of {sup 31}Al and {sup 32}Al have been measured using the {beta}-NMR technique with the polarized RI beams of the Al isotopes.

Kameda, D.; Ueno, H.; Yoshimi, A.; Nagatomo, T.; Sugimoto, T.; Kobayashi, Y.; Watanabe, H.; Ishihara, M. [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, (Japan); Asahi, K.; Uchida, M.; Takemura, M.; Shimada, K.; Takase, K.; Inoue, T.; Kijima, G.; Arai, T.; Suda, S. [Tokyo Institute of Technology, 2-12-1 Oh-Okayama, Meguro-ku, Tokyo 152-8551 (Japan); Nagae, D. [Advanced Science Research Center, Japan Atomic Energy Agency, 2-4, Shirakata-Shirane Tokai, Ibaraki, 319-1195 (Japan); Murata, J.; Kawamura, H. [Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima, Tokyo 171-8501 (Japan)

2008-02-06

265

The beam diagnostic instruments in Beijing radioactive ion-beam facilities isotope separator on-line.  

PubMed

The beam diagnostic instruments for Beijing Radioactive Ion-beam Facilities Isotope Separator On-Line are introduced [B. Q. Cui, Z. H. Peng, Y. J. Ma, R. G. Ma, B. Tang, T. Zhang, and W. S. Jiang, Nucl. Instrum. Methods 266, 4113 (2008); T. J. Zhang, X. L. Guan, and B. Q. Cui, in Proceedings of APAC 2004, Gyeongju, Korea, 2004, http://www.jacow.org, p. 267]. For low intensity ion beam [30-300 keV/1 pA-10 ?A], the beam profile monitor, the emittance measurement unit, and the analyzing slit will be installed. For the primary proton beam [100 MeV/200 ?A], the beam profile scanner will be installed. For identification of the nuclide, a beam identification unit will be installed. The details of prototype of the beam diagnostic units and some experiment results will be described in this article. PMID:24593450

Ma, Y; Cui, B; Ma, R; Tang, B; Chen, L; Huang, Q; Jiang, W

2014-02-01

266

Headgroup interactions and ion flotation efficiency in mixtures of a chelating surfactant, different foaming agents, and divalent metal ions.  

PubMed

The correlation between interaction parameters and ion flotation efficiency in mixtures of chelating surfactant metal complexes and different foaming agents was investigated. We have recently shown that chelating surfactant 2-dodecyldiethylenetriaminepentaacetic acid (4-C12-DTPA) forms strong coordination complexes with divalent metal ions, and this can be utilized in ion flotation. Interaction parameters for mixed micelles and mixed monolayer formation for Mg(2+) and Ni(2+) complexes with the chelating surfactant 4-C12-DTPA and different foaming agents were calculated by Rubingh's regular solution theory. Parameters for the calculations were extracted from surface tension measurements and NMR diffusometry. The effects of metal ion coordination on the interactions between 4-C12-DTPA and the foaming agents could be linked to a previously established difference in coordination chemistry between the examined metal ions. As can be expected from mixtures of amphoteric surfactants, the interactions were strongly pH-dependent. Strong correlation was found between interaction parameter ?(?) for mixed monolayer formation and the phase-transfer efficiency of Ni(2+) complexes with 4-C12-DTPA during flotation in a customized flotation cell. In a mixture of Cu(2+) and Zn(2+), the significant difference in conditional stability constants (log K) between the metal complexes was utilized to selectively recover the metal complex with the highest log K (Cu(2+)) by ion flotation. Flotation experiments in an excess concentration of metal ions confirmed the coordination of more than one metal ion to the headgroup of 4-C12-DTPA. PMID:24824327

Svanedal, Ida; Boija, Susanne; Norgren, Magnus; Edlund, Håkan

2014-06-10

267

Catalytic properties of ion-bombarded non-metals  

NASA Astrophysics Data System (ADS)

Sputtering, ion implantation and ion beam mixing are useful new techniques for producing catalysts consisting of an active metal introduced in a non-active substrate. We studied the performance of implanted and ion beam mixed electrocatalysts containing platinum as the active component in graphite or RuO 2 substrates. The specimens were used as electrodes in electrochemical cells and their activity was studied for the oxidation of formic acid and methanol, the reduction of oxygen and the evolution of hydrogen. All reactions are important for fuel cells and hydrogen production. The intermixing of a thin Pt layer with a RuO 2 substrate by means of 150 keV Kr + beams did not change the activity, normalized to a standard Pt surface concentration, for formic acid oxidation and oxygen reduction. The activity for methanol oxidation, however, decreased with increasing mixing dose and was nearly zero for implanted Pt in RuO 2. For Pt on graphite substrates the activity for all reactions increased with the mixing dose up to 10 16{Kr +}/{cm 2}, and decreased or saturated above this value. The observed dependency of the activity on the individual chemical reaction as well as on the type of substrate was explained provisionally by a cooperation of small particle effects and metal-substrate interactions.

Wolf, G. K.; Zucholl, K.; Folger, H.

1984-02-01

268

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

269

Removal and recovery of metal ions from process and waste streams using polymer filtration  

Microsoft Academic Search

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

G. D. Jarvinen; B. F. Smith; T. W. Robison; K. M. Kraus; J. A. Thompson

1999-01-01

270

Preliminary shielding estimates for the proposed National ISOL Radioactive Ion Beam (RIB) Facility at Oak Ridge  

SciTech Connect

ORNL built a first-generation Radioactive Ion Beam (RIB) facility for astrophysics and nuclear physics research; it was named Holifield Radioactive Ion Beam Facility (HRIBF) and is based on the Isotope Separator On Line (ISOL) technique. Planning is underway for a second- generation facility, the National ISOL RIB facility at Oak Ridge; it will build on the existing HRIBF and may utilize many existing components and shielded areas. Preliminary upgrade plan for the new facility includes: adding a superconducting booster for the tandem accelerator; replacing the 1960-vintage, 60-MeV proton, 50-microamp ORIC (Oak Ridge Isochronous Cyclotron) with a modern 200-MeV proton, 200-microamp cyclotron; and building a high-power {sup 238}U fission target to accept the 200-MeV proton beam. This report summarizes the results of a preliminary 1-D shielding analysis of the proposed upgrade, to determine the shielding requirements for a 0.25 mrem/h dose rate at the external surface of the exclusion area. Steel shielding weights ranging from 60 to 100 metric tons, were considered manageable; these could be reduced by a factor of 2 to 3 if the orientation of the proposed target station was changed.

Johnson, J.O.; Gabriel, T.A.; Lillie, R.A.

1996-10-01

271

Radioactive Ion Beam Production from the Fission of Thorium Oxide Targets  

NASA Astrophysics Data System (ADS)

Hollifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory is one of the few facilities in the world that provides radioactive ion beams (RIB), crucial for nuclear astrophysics, nuclear structure, and stewardship science. Neutron-rich beams are produced by proton-induced nuclear fission of actinide compounds such as uranium carbide or thorium oxide. The goal of this project has two folds. First, compare the beam yield produced from both a low density and a high-density ThO2 target. Second, find the relation the 40 MeV proton beam that drives the RIB production is fully stopped in the high density, ˜8 g/cm^3 ThO2, but not in the low-density 0.8 g/cm^3 ThO^2. The low-density target does not use all of the beam intensity. In this particular experiment, the production yields from 40MeV and 30MeV protons have been measured on the low-density target. The comparison of the calculated production yields of 40 MeV and 30 MeV protons shows a factor of two between these different energies. The experiment was conducted using an on-line mass separator, and specific masses of the RIB were collected onto a tape. This allows a direct comparison of the low and high density ThO2 target. Release data from the high and low-density targets will be shown and discussed.

Armagan, Hakan; Carter, H. K.; Stracener, D. W.; Spejewski, E. H.; Kronenberg, A.

2007-04-01

272

Proceedings of the workshop on the science of intense radioactive ion beams  

SciTech Connect

This report contains the proceedings of a 2-1/2 day workshop on the Science of Intense Radioactive Ion Beams which was held at the Los Alamos National Laboratory on April 10--12, 1990. The workshop was attended by 105 people, representing 30 institutions from 10 countries. The thrust of the workshop was to develop the scientific opportunities which become possible with a new generation intense Radioactive Ion Beam (RIB) facility, currently being discussed within North America. The workshop was organized around five primary topics: (1) reaction physics; (2) nuclei far from stability/nuclear structure; (3) nuclear astrophysics; (4) atomic physics, material science, and applied research; and (5) facilities. Overview talks were presented on each of these topics, followed by 1-1/2 days of intense parallel working group sessions. The final half day of the workshop was devoted to the presentation and discussion of the working group summary reports, closing remarks and a discussion of future plans for this effort.

McClelland, J.B.; Vieira, D.J. (comps.)

1990-10-01

273

Size-dependent patterned recognition and extraction of metal ions by a macrocyclic aromatic pyridone pentamer.  

PubMed

A macrocyclic aromatic pyridine pentamer was found to exhibit patterned recognition of metal ions and efficiently extract larger ions, such as Cs(+), Ba(2+), Tl(+), Au(+), K(+) and Rb(+) preferentially over the other 18 smaller metal ions from the aqueous phase into the chloroform layer. PMID:25200048

Shen, Jie; Ma, Wenliang; Yu, Lin; Li, Jin-Bo; Tao, Hu-Chun; Zhang, Kun; Zeng, Huaqiang

2014-10-28

274

Application of the mobile metal ion technique to routine geochemical exploration  

Microsoft Academic Search

Extractants containing strong ligands may be used to detach unbound or weakly attached metal ions from soils, resulting in `Mobile Metal Ions' (MMI) in concentrations readily measurable by modern-day inductively coupled plasma (ICP) analytical equipment. Mobile forms of metals Cu, Pb, Zn, Ni, Cd, Au, Ag, Co and Pd can be extracted with two digestants, and in general show strong

A. W Mann; R. D Birrell; A. T Mann; D. B Humphreys; J. L Perdrix

1998-01-01

275

The connection between metal ion affinity and ligand affinity in integrin I domains  

E-print Network

The connection between metal ion affinity and ligand affinity in integrin I domains Thomas Vorup in regulating ligand binding has been reported, the relationship between metal ion binding affinity and ligand binding affinity has not been elucidated. Metal and ligand binding by several I domain mutants

Springer, Timothy A.

276

Templated display of biomolecules and inorganic nanoparticles by metal ion-induced peptide nanofibers.  

PubMed

We functionalized peptide nanofibers to provide a nano-scale template for the display of biomolecules and inorganic nanoparticles using metal ion coordination. Nanofibers assembled only in the presence of certain divalent metal ions, and could be readily dissolved by a metal-chelating reagent, EDTA. PMID:20177599

Lee, Byoung-Chul; Zuckermann, Ronald N

2010-03-14

277

High-resolution mass spectrometer for liquid metal ion sources.  

PubMed

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 10(6)-10(7) 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. PMID:24089821

Wortmann, Martin; Ludwig, Arne; Meijer, Jan; Reuter, Dirk; Wieck, Andreas D

2013-09-01

278

EPR investigations of mesoporous silica doped with metal transitions ions  

NASA Astrophysics Data System (ADS)

Electron paramagnetic resonance (EPR) experiments were performed on mesoporous silica powders in which (1,4,8,11-tetraazacyclotetradecane) cyclam groups were incorporated. These functionalised groups allow an easy binding with copper and nickel ions. Comparative studies are carried out on samples functionalised by cyclam groups located either inside the pores or in the walls of the mesoporous structures. Copper and nickel EPR parameters, including g-tensors and hyperfine components are determined and relevant electronic, magnetic and structural information are obtained. The EPR spectra intensities and line-widths are investigated on the temperature range [4 K,300 K] to clarify the relative dispersion or agglomeration of the doping ions in the matrices as well as their possible thermally activated mobility and ions pairing. As a support of the experimental EPR investigations, numerical simulations of the geometry of metallic ion environments and their electronic properties are carried out and discussed. The possibility of dynamic Jahn Teller (JT) effect in the temperature range [200, 60 K] is discussed for the nickel doped matrices where the low temperature quenched JT configuration is thought to favour the formation of Ni3+ pairs.

Kassiba, A.; Makowska-Janusik, M.; Alauzun, J.; Kafrouni, W.; Mehdi, A.; Reyé, C.; Corriu, R. J.; Gibaud, A.

2006-04-01

279

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

280

Spectropolarimetric titrimetry of metal ions and optically active chelating agents  

E-print Network

-Metal Ion Systems Titration of Al(010&)s with standard 1-PDTR 4. Titration of In(C104)s with standard 1-PDTA 5. Titration of Tl(010~)s with standard 1-PDTA 6. Titration oi' ZrO(C10a)a with star. dard 1-PDTR '7. Titrat on of Th(010'). with standard 1...-PDTA 8. Titration of . a(NOs)s with standard 1-PDTA 9. Titration of CeCls with standard 1-PDTA 10. Titration of Pr(0104)s with standard 1-PDTA 11. Titration of Nd(010&)s with standard 1-PDTA 12. Titration oi' Sm(0104)s with standard 1-PDTA 13...

Caldwell, Donald Lee

2012-06-07

281

Assessment of the Antiviral Properties of Zeolites Containing Metal Ions  

Microsoft Academic Search

The antiviral properties of zeolite (sodium aluminosilicate) powders amended with metal ions were assessed using human coronavirus\\u000a 229E, feline infectious peritonitis virus (FIPV), and feline calicivirus F-9. Zeolites containing silver and silver\\/copper\\u000a caused significant reductions of coronavirus 229E after 1 h in suspension. The silver\\/copper combination yielded a >5.13-log10 reduction within 24 h. It was also the most effective (>3.18-log10) against FIPV

Kelly R. Bright; Enue E. Sicairos-Ruelas; Patricia M. Gundy; Charles P. Gerba

2009-01-01

282

Health risk and impact evaluation for recycling of radioactive scrap metal  

SciTech Connect

The DoE, Office of Environmental Restoration and Waste Management, is participating with the Organization for Economic Cooperation and Development in providing analytical support for developing international standards for recycling of radioactive scrap metals. For this purpose, Argonne National Laboratory is assessing health, environmental and societal implications of recycling and/or disposal process alternatives. This effort includes development of international inventory estimates for contaminated metals; investigation of international scrap metal markets; assessment of radiological and non-radiological human health risks; impacts on environmental quality and resources; and investigation of social and political factors. The RSM disposal option is being assessed with regard to the environmental and health impacts of replacing the metals if they are withdrawn from use. Impact estimates are developed for steel as an illustrative example because steel comprises a major portion of the scrap metal inventory. Current and potential sources of RSM include nuclear power plants, fuel cycle and weapons production facilities, industrial and medical facilities and equipment, and petroleum and phosphate rock extraction equipment. Millions of metric tons (t) of scrap iron and steel, stainless steel, and copper, as well as lesser quantities of aluminum, nickel, lead, and zirconium, are likely to become available in the future as these facilities are withdrawn from service.

Nieves, L.A.; Chen, S.Y. [Argonne National Lab., IL (United States); Murphie, W.E.; Lilly, M.J. III [USDOE, Washington, DC (United States)

1994-03-01

283

The Radioactive Ion Beams in Brazil (RIBRAS) facility. Description, program, main results, future plans  

NASA Astrophysics Data System (ADS)

RIBRAS (Radioactive Ion Beams in Brazil) is a facility installed at the Institute of Physics of the University of São Paulo (IFUSP), Brazil. The RIBRAS system consists of two superconducting solenoids and uses the "in-flight method" to produce radioactive ion beams using the primary beam provided by the 8UD Pelletron Tandem of IFUSP. The ion beams produced so far by RIBRAS are 6He, 8Li, 7Be, 10Be, 8B, 12B with intensities that can vary from 104 to 106 pps. Initially the experimental program covered the study of elastic and inelastic scattering with the objective to study the interaction potential and the reaction mechanisms between weakly bound (RIB) and halo (6He and 8B projectiles on light, medium and heavy mass targets. With highly purified beams, the study of resonant elastic scattering and resonant transfer reactions, using inverse kinematics and thick targets, has also been included in our experimental program. Also, transfer reactions of astrophysical interest and fusion reactions induced by halo nuclei are part of the near-future research program. Our recent results on elastic scattering, alpha-particle production and total reaction cross sections, as well as the resonant elastic and transfer reactions, are presented. Our plans for the near future are related to the installation of a new beam line and a cave for gamma-ray detection. We intend to place in operation a large area neutron detector available in our laboratory. The long-range plans could be the move of the RIBRAS system to the more energetic beam line of the LINAC post-accelerator (10MeV/nucleon primary beams) still in construction in our laboratory.

Lépine-Szily, A.; Lichtenthäler, R.; Guimarães, V.

2014-08-01

284

Photoluminescence properties of Jahn-Teller transition-metal ions  

NASA Astrophysics Data System (ADS)

This work investigates the influence of electron-phonon coupling associated with E ?e and T ?e Jahn-Teller (JT) effect in different transition-metal (TM) ions on de-excitation phenomena through nonradiative multiphonon relaxation, i.e., photoluminescence (PL) quenching. We developed a configurational curve model which is able to predict from the absorption spectrum whether a given JT-TM ion is PL or quenched. The prediction is made on the basis of an adapted Dexter-Klick-Russell parameter for JT systems, defined in terms of spectroscopic parameters through ?JT=??eabs/Eabs, where ?eabs refers to the splitting of the parent octahedral Eg states by the JT distortion in E ?e (? =3/4) or T ?e (? =1/4), and Eabs is the energy of the first absorption band involving electronic transition between Eg and T2g. We show that PL in any JT-TM ion occurs whenever ?JT<0.1 or is quenched if ?JT>0.2. This result is noteworthy since it allows us to establish structural requirements for the JT-TM ion and the host crystal to be PL. Although PL properties of materials containing TM ions depend on a variety of structural factors such as the electronic configuration, the site symmetry, and the crystal field produced by neighboring atoms, the present model achieves this goal through a simple spectroscopic parameter: ?JT. In this work we correlated the PL properties of different sixfold-coordinated JT systems such as Ti3+, Cu2+, Mn3+, Cr2+, Fe2+, Co3+, and Ni3+ in halides and oxides with ?JT obtained from their respective absorption spectra. From this analysis we conclude that depending on the nature of the JT coupling and its strength, PL is either strongly favored or quenched in T ?e while it is mostly quenched in E ?e systems due to the larger JT distortion.

Sanz-Ortiz, Marta N.; Rodríguez, Fernando

2009-09-01

285

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

286

Anion-exchange separations of metal ions in thiocyanate media.  

PubMed

The analytical potential of a weak-base macroreticular anion-exchange resin for the quantitative separation of metal ions in thiocyanate media is investigated and demonstrated. Distribution data are given for the sorption of some 25 metal ions from aqueous mixtures of potassium thiocyanate (1.0M or less) and 0.5M hydrochloric acid. The magnitude of the distribution data suggests many possible separations, some of which were quantitatively performed by procedures which are fast, simple and require only mild conditions. Representative separations are removal of traces of iron(III) and copper(II) from water samples prior to the determination of water hardness (calcium and magnesium), separation of nickel(II) from vanadium(IV) and the separation of thorium(IV) from titanium(IV). Some multicomponent separations are the separation of rare earths(III) and thorium(IV) from scandium(III) and the separation of rare earths(III) from iron(III) and uranium(VI). PMID:18960914

Fritz, J S; Kaminski, E E

1971-05-01

287

The kinetics and mechanism of bromide ion isotope exchange reaction in strongly basic anion-exchange resin duolite A-162 determined by the radioactive tracer technique  

Microsoft Academic Search

In the present investigation, 82Br radioactive isotope was used as a tracer to study the kinetics and mechanism of exchange reaction between an ion exchange\\u000a resin and an external bromide ion solution. In an attempt to study the reversible bromide ion isotopic exchange reaction kinetics,\\u000a it was expected that whether the initial step was the exchange of radioactive bromide ions

R. S. Lokhande; P. U. Singare; P. Karthikeyan

2007-01-01

288

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

289

Selective recovery of gold and other metal ions from an algal biomass  

Microsoft Academic Search

The authors observed that the pH dependence of the binding of Au\\/sup 3 +\\/, Ag\\/sup +\\/, and Hg\\/sup 2 +\\/ to the algae Chlorella vulgaris is different than the binding of other metal ions. Between pH 5 and 7, a variety of metal ions bind strongly to the cell surface. Most of these algal-bound metal ions can be selectively desorbed

Dennis W. Darnall; Benjamin Greene; Michael T. Henzl; J. Michael Hosea; Robert A. McPherson; Joseph Sneddon; M. Dale Alexander

1986-01-01

290

Measurement of hold-up times in a thermal ion source for metallic and monoxide ions of lanthanum and cerium  

Microsoft Academic Search

Hold-up times of ions in a thermal ion source were measured for lanthanum and cerium together with neighboring elements in the periodic table. The hold-up times of metallic and monoxide ions of both lanthanum and cerium were found to be almost the same and much longer than those of cesium, barium, praseodymium and neodymium ions. The observed long hold-up times

S. Ichikawa; T. Sekine; H. Iimura; M. Oshima

1992-01-01

291

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

292

Removal of radioactive materials and heavy metals from water using magnetic resin  

DOEpatents

Magnetic polymer resins capable of efficient removal of actinides and heavy metals from contaminated water are disclosed together with methods for making, using, and regenerating them. The resins comprise polyamine-epichlorohydrin resin beads with ferrites attached to the surfaces of the beads. Markedly improved water decontamination is demonstrated using these magnetic polymer resins of the invention in the presence of a magnetic field, as compared with water decontamination methods employing ordinary ion exchange resins or ferrites taken separately.

Kochen, Robert L. (Boulder, CO); Navratil, James D. (Simi Valley, CA)

1997-01-21

293

Removal of radioactive materials and heavy metals from water using magnetic resin  

DOEpatents

Magnetic polymer resins capable of efficient removal of actinides and heavy metals from contaminated water are disclosed together with methods for making, using, and regenerating them. The resins comprise polyamine-epichlorohydrin resin beads with ferrites attached to the surfaces of the beads. Markedly improved water decontamination is demonstrated using these magnetic polymer resins of the invention in the presence of a magnetic field, as compared with water decontamination methods employing ordinary ion exchange resins or ferrites taken separately. 9 figs.

Kochen, R.L.; Navratil, J.D.

1997-01-21

294

Ligational behavior of Schiff bases towards transition metal ion and metalation effect on their antibacterial activity  

NASA Astrophysics Data System (ADS)

New Schiff bases pyrazine-2-carboxylicacid (phenyl-pyridin-2-yl-methylene)-hydrazide (Hpch-bp) HL1 and pyrazine-2-carboxylicacid (pyridin-2-ylmethylene)-hydrazide (Hpch-pc) HL2 derived from condensation of pyrazine carboxylic hydrazide (Hpch) with 2-benzoyl pyridine (bp) or pyridine 2-carbaldehyde (pc) and their transition metal complexes of type ML(1-2)2 have been synthesized, where M = Mn(II), Co(II), Ni(II), Cu(II) and Zn(II). Characterization of ligands and their metal complexes was carried out by elemental analysis, conductimetric studies, magnetic susceptibility, spectroscopic techniques (IR, UV-VIS, NMR, ESR, Mass) and thermogravimetric analysis. The physico-chemical studies revealed octahedral geometry or distorted octahedral geometry around metal ion. These azomethine Schiff base ligands acted as tridentate ? coordinating through carbonyl, azomethine and pyridine nitrogen present in the ligand. The thermodynamic and thermal properties of the complexes have been investigated and it was observed on the basis of these studies that thermal stability of complexes follows the order Mn < Zn < Cu < Co < Ni. The ligands and their complexes were tested for in vitro antibacterial activity at different concentrations against bacteria viz. Gram positive Bacillus subtilis, Micrococcus luteus and Gram negative Pseudomonas aeruginosa, Pseudomonas mendocina. A marked enhancement in biocidal activity of the ligands under similar experimental conditions was observed as a consequence of coordination with metal ions. The trend of growth inhibition in the complexes was found to be in the order: Cu > Mn > Ni > Co > Zn.

Devi, Jai; Batra, Nisha; Malhotra, Rajesh

2012-11-01

295

Development of Radioactive Ion Beam Purification by Selective Adsorption at the HRIBF  

NASA Astrophysics Data System (ADS)

In the past decades many techniques have been developed to reduce isobaric contaminations in ISOL (Isotope Separation On-Line) beams. Another promising method to achieve improved selectivity is employing surface effects in the transfer line between target container and ion source. Thus adsorption materials with suitable atomic structure and polarity can lead to a high chemical selectivity. The principle of selective adsorption has already been employed successfully in the past. Quartz transfer lines are applied on-line at ISOLDE and have been shown to reduce Rb contaminations by 5 orders of magnitude. Since quartz is the only compound that has been tested yet we plan to conduct a broad on-line study of the adsorption behavior of various elements on a range of materials. For testing at the On-Line Test Facility at the Holifield Radioactive Ion Beam Facility (HRIBF) a special target-ion source unit with a variable-temperature transfer line has been constructed in collaboration with the ISOLDE technical group. Based on the design of the ISOLDE prototype unit it was modified to match the unique capabilities of the OLTF. Preliminary results of on-line tests are presented.

Jost, C.; Carter, H. K.; Goans, R. E.; Griffith, B. O.; Katakam, R.; Kratz, K.-L.; Reed, C. A.; Spejewski, E. H.; Stora, T.; Stracener, D. W.

2009-03-01

296

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

297

Amorphous Metallic Glass as New High Power and Energy Density Anodes For Lithium Ion Rechargeable Batteries  

E-print Network

We have investigated the use of aluminum based amorphous metallic glass as the anode in lithium ion rechargeable batteries. Amorphous metallic glasses have no long-range ordered microstructure; the atoms are less closely ...

Meng, Shirley Y.

298

Most spin-1/2 transition-metal ions do have single ion anisotropy  

NASA Astrophysics Data System (ADS)

The cause for the preferred spin orientation in magnetic systems containing spin-1/2 transition-metal ions was explored by studying the origin of the easy-plane anisotropy of the spin-1/2 Cu2+ ions in CuCl2.2H2O, LiCuVO4, CuCl2, and CuBr2 on the basis of density functional theory and magnetic dipole-dipole energy calculations as well as a perturbation theory treatment of the spin-orbit coupling. We find that the spin orientation observed for these spin-1/2 ions is not caused by their anisotropic spin exchange interactions, nor by their magnetic dipole-dipole interactions, but by the spin-orbit coupling associated with their crystal-field split d-states. Our study also predicts in-plane anisotropy for the Cu2+ ions of Bi2CuO4 and Li2CuO2. The results of our investigations dispel the mistaken belief that magnetic systems with spin-1/2 ions have no magnetic anisotropy induced by spin-orbit coupling.

Liu, Jia; Koo, Hyun-Joo; Xiang, Hongjun; Kremer, Reinhard K.; Whangbo, Myung-Hwan

2014-09-01

299

High-pressure ion-thermal properties of metals from ab initio interatomic potentials  

SciTech Connect

It has recently become possible for the first time to calculate ab initio two-ion and three-ion interatomic potentials in d-electron transition metals. The nature of these potentials for the 3d series metals is discussed. In the case of copper, where three-ion contributions may be neglected, application is made to the ion-thermal component of the equation of state and to the calculation of melting on the shock Hugoniot. 13 refs., 3 figs.

Moriarty, J.A.

1985-06-01

300

Nanoparticles reduce nickel allergy by capturing metal ions  

NASA Astrophysics Data System (ADS)

Approximately 10% of the population in the USA suffer from nickel allergy, and many are unable to wear jewellery or handle coins and other objects that contain nickel. Many agents have been developed to reduce the penetration of nickel through skin, but few formulations are safe and effective. Here, we show that applying a thin layer of glycerine emollient containing nanoparticles of either calcium carbonate or calcium phosphate on an isolated piece of pig skin (in vitro) and on the skin of mice (in vivo) prevents the penetration of nickel ions into the skin. The nanoparticles capture nickel ions by cation exchange, and remain on the surface of the skin, allowing them to be removed by simple washing with water. Approximately 11-fold fewer nanoparticles by mass are required to achieve the same efficacy as the chelating agent ethylenediamine tetraacetic acid. Using nanoparticles with diameters smaller than 500 nm in topical creams may be an effective way to limit the exposure to metal ions that can cause skin irritation.

Vemula, Praveen Kumar; Anderson, R. Rox; Karp, Jeffrey M.

2011-05-01

301

Prostate cancer outcome and tissue levels of metal ions  

USGS Publications Warehouse

BACKGROUND There are several studies examining prostate cancer and exposure to cadmium, iron, selenium, and zinc. Less data are available on the possible influence of these metal ions on prostate cancer outcome. This study measured levels of these ions in prostatectomy samples in order to examine possible associations between metal concentrations and disease outcome. METHODS We obtained formalin fixed paraffin embedded tissue blocks of prostatectomy samples of 40 patients with PSA recurrence, matched 1:1 (for year of surgery, race, age, Gleason grading, and pathology TNM classification) with tissue blocks from 40 patients without recurrence (n = 80). Case-control pairs were compared for the levels of metals in areas adjacent to tumors. Inductively coupled plasma-mass spectrometry (ICP-MS) was used for quantification of Cd, Fe, Zn, and Se. RESULTS Patients with biochemical (PSA) recurrence of disease had 12% lower median iron (95 ??g/g vs. 111 ??g/g; P = 0.04) and 21% lower zinc (279 ??g/g vs. 346 ??g/g; P = 0.04) concentrations in the normal-appearing tissue immediately adjacent to cancer areas. Differences in cadmium (0.489 ??g/g vs. 0.439 ??g/g; 4% higher) and selenium (1.68 ??g/g vs. 1.58 ??g/g; 5% higher) levels were not statistically significant in recurrence cases, when compared to non-recurrences (P = 0.40 and 0.21, respectively). CONCLUSIONS There is an association between low zinc and low iron prostate tissue levels and biochemical recurrence in prostate cancer. Whether these novel findings are a cause or effect of more aggressive tumors, or whether low zinc and iron prostatic levels raise implications for therapy, remains to be investigated. Copyright ?? 2011 Wiley-Liss, Inc.

Sarafanov, A. G.; Todorov, T. I.; Centeno, J. A.; MacIas, V.; Gao, W.; Liang, W. -M.; Beam, C.; Gray, M. A.; Kajdacsy-Balla, A. A.

2011-01-01

302

Structure of the alkali-metal-atom + strontium molecular ions: Towards photoassociation and formation of cold molecular ions  

SciTech Connect

The potential energy curves, permanent and transition dipole moments, and the static dipolar polarizability, of molecular ions composed of one alkali-metal atom and a strontium ion are determined with a quantum chemistry approach. The molecular ions are treated as effective two-electron systems and are treated using effective core potentials including core polarization, large gaussian basis sets, and full configuration interaction. In the perspective of upcoming experiments aiming at merging cold atom and cold ion traps, possible paths for radiative charge exchange, photoassociation of a cold lithium or rubidium atom and a strontium ion are discussed, as well as the formation of stable molecular ions.

Aymar, M.; Dulieu, O. [Laboratoire Aime Cotton, CNRS, UPR3321, Ba circumflex t. 505, Univ Paris-Sud, 91405 Orsay Cedex (France); Guerout, R. [Laboratoire Kastler-Brossel, CNRS, ENS, Univ Pierre et Marie Curie case 74, Campus Jussieu, F-75252 Paris Cedex 05 (France)

2011-08-14

303

Peroxide Stress Elicits Adaptive Changes in Bacterial Metal Ion Homeostasis  

PubMed Central

Abstract Exposure to hydrogen peroxide (H2O2) and other reactive oxygen species is a universal feature of life in an aerobic environment. Bacteria express enzymes to detoxify H2O2 and to repair the resulting damage, and their synthesis is typically regulated by redox-sensing transcription factors. The best characterized bacterial peroxide-sensors are Escherichia coli OxyR and Bacillus subtilis PerR. Analysis of their regulons has revealed that, in addition to inducible detoxification enzymes, adaptation to H2O2 is mediated by modifications of metal ion homeostasis. Analogous adaptations appear to be present in other bacteria as here reviewed for Deinococcus radiodurans, Neisseria gonorrhoeae, Streptococcus pyogenes, and Bradyrhizobium japonicum. As a general theme, peroxide stress elicits changes in cytosolic metal distribution with the net effect of reducing the damage caused by reactive ferrous iron. Iron levels are reduced by repression of uptake, sequestration in storage proteins, and incorporation into metalloenzymes. In addition, peroxide-inducible transporters elevate cytosolic levels of Mn(II) and/or Zn(II) that can displace ferrous iron from sensitive targets. Although bacteria differ significantly in the detailed mechanisms employed to modulate cytosolic metal levels, a high Mn:Fe ratio has emerged as one key correlate of reactive oxygen species resistance. Antioxid. Redox Signal. 15, 175–189. PMID:20977351

Faulkner, Melinda J.

2011-01-01

304

Selective adsorption of metal ions by chemically-modified MCM-41  

Microsoft Academic Search

Selective adsorbents were developed for removal and recovery of heavy metals from aqueous medium. As heavy metals interact with surface moieties differently depending on their chemical properties, tailor-made adsorbents were synthesized for metal separation from aqueous solution based on different adsorption mechanisms. This is the first comprehensive study in the design of adsorbent for selective adsorption of metal ions based

Koon Fung Lam

2006-01-01

305

Performance of the Recoil Mass Spectrometer and its detector systems at the Holifield Radioactive Ion Beam Facility  

Microsoft Academic Search

The recently commissioned Recoil Mass Spectrometer (RMS) at the Holifield Radioactive Ion Beam Facility (HRIBF) is described. Consisting of a momentum separator followed by an E-D-E Rochester-type mass spectrometer, the RMS is the centerpiece of the nuclear structure endstation at the HRIBF. Designed to transport ions with rigidities near K=100, the RMS has acceptances of ±10% in energy and ±4.9%

C. J Gross; T. N Ginter; D. Shapira; W. T Milner; J. W McConnell; A. N James; J. W Johnson; J. Mas; P. F Mantica; R. L Auble; J. J. Das; J. L Blankenship; J. H Hamilton; R. L Robinson; Y. A Akovali; C. Baktash; J. C Batchelder; C. R Bingham; M. J Brinkman; H. K Carter; R. A Cunningham; T. Davinson; J. D Fox; A. Galindo-Uribarri; R. Grzywacz; J. F Liang; B. D MacDonald; J. MacKenzie; S. D Paul; A. Piechaczek; D. C Radford; A. V. Ramayya; W. Reviol; D. Rudolph; K. Rykaczewski; K. S Toth; W. Weintraub; C. Williams; P. J Woods; C.-H Yu; E. F Zganjar

2000-01-01

306

Beam dynamics design studies of a superconducting radioactive ion beam postaccelerator  

NASA Astrophysics Data System (ADS)

The HIE-ISOLDE project at CERN proposes a superconducting upgrade to increase the energy range and quality of the radioactive ion beams produced at ISOLDE, which are currently postaccelerated by the normal conducting radioactive ion beam experiment linac. The specification and design choices for the HIE-ISOLDE linac are outlined along with a comprehensive beam dynamics study undertaken to understand and mitigate the sources of beam emittance dilution. The dominant cause of transverse emittance growth was attributed to the coupling between the transverse and longitudinal motions through the phase dependence of the rf defocusing force in the accelerating cavities. A parametric resonance induced by the coupling was observed and its excitation surveyed as a function of transverse phase advance using numerical simulations and analytic models to understand and avoid the regions of transverse beam instability. Other sources of emittance growth were studied and where necessary ameliorated, including the beam steering force in the quarter-wave resonator and the asymmetry of the rf defocusing forces in the solenoid focusing channel. A racetrack shaped beam port aperture was shown to improve the symmetry of the fields in the high-? quarter-wave resonator and reduce the loss of acceptance under the offset used to compensate the steering force. The methods used to compensate the beam steering are described and an optimization routine written to minimize the steering effect when all cavities of a given family are offset by the same amount, taking into account the different velocity profiles across the range of mass-to-charge states accepted. The assumptions made in the routine were shown to be adequate and the results well correlated with the beam quality simulated in multiparticle beam dynamics simulations. The specification of the design tolerances is outlined based on studies of the sensitivity of the beam to misalignment and errors, with particular emphasis on the phase and amplitude stability required for the independently phased quarter-wave resonators.

Fraser, M. A.; Jones, R. M.; Pasini, M.

2011-02-01

307

Transition metal ions at the crossroads of mucosal immunity and microbial pathogenesis  

PubMed Central

Transition metal ions are essential micronutrients for all living organisms. In mammals, these ions are often protein-bound and sequestered within cells, limiting their availability to microbes. Moreover, in response to infection, mammalian hosts further reduce the availability of metal nutrients by activating epithelial cells and recruiting neutrophils, both of which release metal-binding proteins with antimicrobial function. Microorganisms, in turn, have evolved sophisticated systems to overcome these limitations and acquire the metal ions essential for their growth. Here we review some of the mechanisms employed by the host and by pathogenic microorganisms to compete for transition metal ions, with a discussion of how evading “nutritional immunity” benefits pathogens. Furthermore, we provide new insights on the mechanisms of host-microbe competition for metal ions in the mucosa, particularly in the inflamed gut. PMID:24478990

Diaz-Ochoa, Vladimir E.; Jellbauer, Stefan; Klaus, Suzi; Raffatellu, Manuela

2013-01-01

308

Complexometric determination of metal ions by microscopic diffusional titration.  

PubMed

Acid/base titrations of pico- and femtoliter microsamples have been performed previously using a diffusional microburet (DMB) for reagent delivery in a simple droplet-heptane system (Gratzl, M.; Yi, C. Anal. Chem. 1993, 65, 2085-2088). The lowest delivery rate achieved with a DMB was about 6 fmol/s, which would correspond to about a 1 microL/year volumetric flow rate with a hypothetical equivalent mechanical delivery scheme (Yi, C.; Gratzl, M. Anal. Chem. 1994, 66, 1976-1982). In this work, the feasibility of complexometric titrations in microscopic samples is explored. Stability of pH in the microdroplets required for different determinations and the effects of DMB shank geometry on titration characteristics are also studied. Diffusional microtitrations of Fe(III), Zn(II), and Cu(II) have been performed with EDTA. Xylenol orange and Eriochrome Black T provide clear color changes at the end point of the respective titrations, despite the microscopic size of the samples (between 16 and 1570 pL, corresponding to diameters between 30 and 144 microns). Random errors of the determinations relative to full scale were 6.6% for Fe(III), 5.8% for Cu(II), and 7.9% for Zn(II). The pH required for EDTA titrations of the individual metal ions stays stable in the acidic range. This makes the microscopic titration of a number of metal ions, such as Fe(III), Fe(II), Cu(II), and Pb(II), feasible in a simple droplet-heptane system without any modification. With a higher density of strongly alkaline buffer droplets (about 100 droplets/mm2) sprayed on the bottom of the Petri dish, or by flushing N2 above the heptane, the microscopic samples can also be kept alkaline despite ambient CO2 present. In this way, Zn(II) can also be titrated in microdroplets, requiring a pH around 10. This work renders it possible to perform a variety of complexometric titrations and other chemical manipulations in microdroplets even if they need to be kept alkaline. Similar titrations in single biological cells to assess intracellular buffer capacities of different metal ions, such as Ca(II) and Mg(II), are underway. PMID:8815747

Yi, C; Huang, D; Gratzl, M

1996-05-01

309

Preparation and characterization of imprinted monolith with metal ion as pivot.  

PubMed

This report provided the first example of using pivot concept to prepare monolithic molecularly imprinted polymers (MIPs) with ketoprofen (KET) imprints, in which metal ions were employed as mediator between the functional monomer and the template to achieve higher fidelity of imprint. To solve metal ions in pre-polymerization system, a new ternary porogen of dimethyl sulfoxide-toluene-isooctane was developed for preparation of MIP monoliths with high porosity and good permeability. The effect of polymerization parameters such as the nature of metal ions, the ratio of template to metal ion and the degree of crosslinking, on the permeability, morphology and affinity of the metal ion mediated MIP monolith were studied. The experiments demonstrated that Ni(2+), Co(2+) and Zn(2+) can be applied as pivot to prepare KET-imprinted monolith. Relative to monolithic MIP without metal ions, all the ion-mediated macropore MIP monoliths showed enhanced permeability, capacity factor and selectivity factor. High permeability (1.06×10(-7)mm(2)) was obtained on the Co(2+)-mediated MIP monolith and great selectivity factor (3.84) was achieved on the Ni(2+)-mediated one. The stoichiometric displacement model was constructed to investigate the recognition mechanism of metal-ion mediated MIP. The results indicate that metal ion as pivot not only improves the affinity but also allows the fine-tuning on the macroporous structure of MIP monolith. PMID:22074646

Zhao, Liang; Ban, Lu; Zhang, Qing-Wei; Huang, Yan-Ping; Liu, Zhao-Sheng

2011-12-16

310

Some aspects of metallic ion chemistry and dynamics in the mesosphere and thermosphere  

NASA Technical Reports Server (NTRS)

The relationship between the formation of sporadic layers of metallic ion and the dumping of these ions into the upper mesosphere is discussed in terms of the tidal wind, classical (i.e., windshear) and other more complex, perhaps highly nonlinear layer formation mechanisms, and a possible circulation mechanism for these ions. Optical, incoherent scatter radar, rocket, and satellite derived evidence for various layer formation mechanisms and for the metallic ion circulation system is reviewed. The results of simple one dimensional numerical model calculations of sporadic E and intermediate layer formation are presented along with suggestions for more advanced models of intense or blanketing sporadic E. The flux of metallic ions dumped by the tidal wind system into the mesosphere is estimated and compared with estimates of total particle flux of meteoric origin. Possible effects of the metallic ion flux and of meteoric dust on D region ion chemistry are discussed.

Mathews, J. D.

1987-01-01

311

Process for the displacement of cyanide ions from metal-cyanide complexes  

DOEpatents

The present invention relates to water-soluble polymers and the use of such water-soluble polymers in a process for the displacement of the cyanide ions from the metal ions within metal-cyanide complexes. The process waste streams can include metal-cyanide containing electroplating waste streams, mining leach waste streams, mineral processing waste streams, and related metal-cyanide containing waste streams. The metal ions of interest are metals that give very strong complexes with cyanide, mostly iron, nickel, and copper. The physical separation of the water-soluble polymer-metal complex from the cyanide ions can be accomplished through the use of ultrafiltration. Once the metal-cyanide complex is disrupted, the freed cyanide ions can be recovered for reuse or destroyed using available oxidative processes rendering the cyanide nonhazardous. The metal ions are released from the polymer, using dilute acid, metal ion oxidation state adjustment, or competing chelating agents, and collected and recovered or disposed of by appropriate waste management techniques. The water-soluble polymer can then be recycled. Preferred water-soluble polymers include polyethyleneimine and polyethyleneimine having a catechol or hydroxamate group.

Smith, Barbara F. (Los Alamos, NM); Robinson, Thomas W. (Los Alamos, NM)

1997-01-01

312

Ion source development for isotope separator on-line based radioactive nuclear beam facility at KEK-Tanashi  

NASA Astrophysics Data System (ADS)

For an isotope separator on-line based radioactive nuclear beam facility at KEK-Tanashi, two different types of ion sources are currently employed: a single stage 6.4 GHz electron cyclotron resonance ion source for 18Ne2+ and 19Ne2+ ions and a surface ionization-type ion source for 8Li1+ ions. The production target for Ne radioisotopes is LiF powder. Enclosed in a water-cooled Cu target cell, the target can sustain proton beam power of 120 W for a long term. The methods to suppress unwanted isotopes, like 19F in 19Ne and 18O in 18Ne, are discussed. For the production of 8Li1+ with the surface ionization-type ion source, a recoil-catcher method is adopted. The feasibility is discussed, comparing to a thick target method.

Jeong, S. C.; Ishiyama, H.; Ishida, Y.; Kawakami, H.; Kawashima, H.; Miyatake, H.; Mizutani, S.; Oyaizu, M.; Takaku, S.; Tojyo, E.; Yoshikawa, N.; Wada, M.; Katayama, I.; Nomura, T.

2000-02-01

313

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

314

Novel fungus-titanate bio-nanocomposites as high performance adsorbents for the efficient removal of radioactive ions from wastewater  

NASA Astrophysics Data System (ADS)

Reclaimable adsorbents have a critical application in the adsorption of radioactive materials. In this study, the novel bio-nanocomposites comprising fungi and titanate nanotubes are successfully synthesized by a simple and low-cost method. Morphological characterizations and composite mechanism analysis confirm that the composites are sufficiently stable to avoid dust pollution resulting from the titanate nanomaterials. Adsorption experiments demonstrate that the bio-nanocomposites are efficient adsorbents with a saturated sorption capacity as high as 120 mg g-1 (1.75 meq. g-1) for Ba2+ ions. The results suggest that the bio-nanocomposites can be used as promising radioactive adsorbents for removing radioactive ions from water caused by nuclear leakage.Reclaimable adsorbents have a critical application in the adsorption of radioactive materials. In this study, the novel bio-nanocomposites comprising fungi and titanate nanotubes are successfully synthesized by a simple and low-cost method. Morphological characterizations and composite mechanism analysis confirm that the composites are sufficiently stable to avoid dust pollution resulting from the titanate nanomaterials. Adsorption experiments demonstrate that the bio-nanocomposites are efficient adsorbents with a saturated sorption capacity as high as 120 mg g-1 (1.75 meq. g-1) for Ba2+ ions. The results suggest that the bio-nanocomposites can be used as promising radioactive adsorbents for removing radioactive ions from water caused by nuclear leakage. Electronic supplementary information (ESI) available: The experimental section and supplementary figures are shown in supplementary information. See DOI: 10.1039/c3nr03467d

Xu, Mingze; Wei, Guodong; Liu, Na; Zhou, Liang; Fu, Chengwei; Chubik, M.; Gromov, A.; Han, Wei

2013-12-01

315

Grid-controlled metal ion sources for heavy ion fusion accelerators  

SciTech Connect

A variety of metal ions can be generated using vacuum arcs, but due to the nature of these arcs, the flux generated fluctuates in time. We have successfully employed electrostatically biased grids to control the plasma and to provide a well-behaved, space charge limited ion source. The grid prevents the plasma from entering the extraction gap before the main voltage pulse is applied. The extracte ion is space charge limited, resulting in a constant output current even though the ion flux from the vacuum arc source varies considerably. There are several advantages over conventional sources. For instance, thermionic sources are faced with heating problems for large area configurations, while gas-injection sources cause prefill problems because they take too long to reach equilibrium. We have performed extraction experiments with aluminum and indium arc sources. We have extracted 300 mA of pure Al/sup +/ at 30 kV for 10 ..mu..s. The normalized beam emittance has been measured to be 3 x 10/sup -7/ ..pi..-m-rad.

Len, L.K.; Humphries S. Jr.; Burkhart, C.

1986-01-21

316

Grid-controlled metal ion sources for heavy ion fusion accelerators  

NASA Astrophysics Data System (ADS)

A variety of metal ions can be generated using vacuum arcs, but due to the nature of these arcs, the flux generated fluctuates in time. We have successfully employed electrostatically biased grids to control the plasma and to provide a well-behaved, space charge limited ion source. The grid prevents the plasma from entering the extraction gap before the main voltage pulse is applied. The extracte ion is space charge limited, resulting in a constant output current even though the ion flux from the vacuum arc source varies considerably. There are several advantages over conventional sources. For instance, thermionic sources are faced with heating problems for large area configurations, while gas-injection sources cause prefill problems because they take too long to reach equilibrium. We have performed extraction experiments with aluminum and indium arc sources. We have extracted 300 mA of pure Al+ at 30 kV for 10 ?s. The normalized beam emittance has been measured to be 3×10-7 ?-m-rad.

Len, L. K.; Humphries, S.; Burkhart, C.

1986-01-01

317

Grid-controlled metal ion sources for heavy ion fusion accelerators  

SciTech Connect

A variety of metal ions can be generated using vacuum arcs, but due to the nature of these arcs, the flux generated fluctuates in time. We have successfully employed electrostatically biased grids to control the plasma and to provide a well-behaved, space charge limited ion source. The grid prevents the plasma from entering the extraction gap before the main voltage pulse is applied. The extracted ion current is space charge limited, resulting in a constant output current even though the ion flux from the vacuum arc source varies considerably. There are several advantages over other conventional sources, for instance, thermionic sources are faced with heating problems especially for large area configurations, while gas-injection sources cause prefill problems because they take too long to reach equilibrium. We have performed extraction experiments with aluminium and indium arc sources. We have extracted 300 mA of pure Al/sup +/ at 30 kV for 10 ..mu..s. The normalized beam emittance has been measured to be 8 /times/ 10/sup /minus/7/ ..pi..-m-rad. 3 refs., 5 figs.

Len, L.K.; Humphries, S. Jr.; Burkart, C.

1986-01-01

318

Ion-irradiation studies of cascade damage in metals  

SciTech Connect

Ion-irradiation studies of the fundamental aspects of cascade damage in metals are reviewed. The emphasis of these studies has been the determination of the primary state of damage (i.e. the arrangement of atoms in the cascade region prior to thermal migration of defects). Progress has been made towards understanding the damage function (i.e. the number of Frenkel pairs produced as a function of primary recoil atom energy), the spatial configuration of vacancies and interstitials in the cascade and the cascade-induced mixing of atoms. It is concluded for these studies that the agitation of the lattice in the vicinity of energetic displacement cascades stimulates the defect motion and that such thermal spike motion induces recombination and clustering of Frenkel defects. 9 figures.

Averback, R.S.

1982-03-01

319

Bacterial outer membrane channel for divalent metal ion acquisition  

PubMed Central

The prevailing model of bacterial membrane function predicts that the outer membrane is permeable to most small solutes because of pores with limited selectivity based primarily on size. Here, we identified mnoP in the Gram-negative bacterium Bradyrhizobium japonicum as a gene coregulated with the inner membrane Mn2+ transporter gene mntH. MnoP is an outer membrane protein expressed specifically under manganese limitation. MnoP acts as a channel to facilitate the tranlocation of Mn2+, but not Co2+ or Cu2+, into reconstituted proteoliposomes. An mnoP mutant is defective in high-affinity Mn2+ transport into cells and has a severe growth phenotype under manganese limitation. We suggest that the outer membrane is a barrier to divalent metal ions that requires a selective channel to meet the nutritional needs of the cell. PMID:21880957

Hohle, Thomas H.; Franck, William L.; Stacey, Gary; O'Brian, Mark R.

2011-01-01

320

Highly charged Ar{sup q+} ions interacting with metals  

SciTech Connect

Using computer simulation, alternative methods of the interaction of highly charged ions Ar{sup q+} with metals (Au, Ag) are used and verified in the present work. Based on the classical over-barrier model, we discussed the promotion loss and peeling off processes. The simulated total potential electron yields agree well with the experiment data in incident energy ranging from 100 eV to 5 keV and all charge states of Ar{sup q+}. Based on the TRIM code, we obtain the side-feeding rate as well as the motion and charge transfer of HCI below the surface. Some results, including the array of KL{sup x} x-ray satellite lines, the respective contribution of autoionization, and side-feeding to inner shells, and the filling rates and lifetime of inner shells for Ar agree well with experiment or theory.

Wang Jijin; Zhang Jian; Gu Jiangang; Luo Xianwen; Hu Bitao [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China)

2009-12-15

321

Natural radioactivity and trace metals in crude oils: implication for health.  

PubMed

Crude oil samples were collected from six different fields in the central Niger Delta in order to determine their natural radioactivity and trace element contents, with the aim of assessing the radiological health implications and environmental health hazard of the metals, and also to provide natural radioactivity baseline data that could be used for more comprehensive future study in this respect. The activity concentrations of the radionuclides were measured using a well, accurately calibrated and shielded vertical cryostat, Canberra coaxial high-purity germanium (HPGe) detector system, and the derived doses were evaluated. The metal concentrations were determined by the graphite furnace atomic absorption spectroscopic (GFAAS) method. The radionuclides identified with reliable regularity belong to the decay series of naturally occurring radionuclides headed by (238)U and (232)Th along with the non-decay series radionuclide, (40)K. The averaged activity concentrations obtained were 10.52 +/- 0.03 Bq kg(-1), 0.80 +/- 0.37 Bq kg(-1) and 0.17 +/- 0.09 Bq kg(-1) for (40)K, (238)U and (232)Th, respectively. The equivalent doses were very low, ranging from 0.0028 to 0.012 mSv year(-1) with a mean value of 0.0070 mSv year(-1). The results obtained were low, and hence, the radioactivity content from the crude oils in the Niger delta oil province of Nigeria do not constitute any health hazard to occupationally exposed workers, the public and the end user. The concentrations of the elements (As, Cd, Co, Fe, Mn, Ni, Se and V) determined ranged from 0.73 to 202.90 ppb with an average of 74.35 ppb for the oil samples analysed. The pattern of occurrence of each element agreed with the earlier studies from other parts of the Niger Delta. It was obvious from this study and previous ones that the Niger Delta oils have low metal contents. However, despite the low concentrations, they could still pose an intrinsic health hazard considering their cumulative effects in the environment. Also, various studies on the impact of oil spillage and activities of oil exploration and production on organisms in the immediate environment suggest this. PMID:18320332

Ajayi, T R; Torto, N; Tchokossa, P; Akinlua, A

2009-02-01

322

Kinetics of heavy metal ions removal by use of natural zeolite.  

PubMed

Kinetics of the uptake of cadmium, lead, copper, nickel and zinc ions from single ion solutions and from their mixture by zeolitic rock has been studied. Removal of ions obeyed the kinetic equation for adsorption. Corresponding adsorption constants and distribution coefficients were determined for each metal ion uptake from single ion solution or mixture. An attempt was made to explain zeolite selectivity to different metal ions and the influence of water hardness on the uptake in terms of metal ionic radii and enthalpy of hydration. It was found that lead ions were strongly immobilized by the zeolite investigated, both from single ion and mixed solutions, as well as from soft and hard water. PMID:11846275

Panayotova, Marinela; Velikov, Borislav

2002-01-01

323

Metal-clad optical waveguide fluorescence device for the detection of heavy metal ions  

NASA Astrophysics Data System (ADS)

We developed Hg-sensing chips by decorating the external surface of metal-clad optical waveguides with a monolayer of Hg-sensitive fluorescent molecular probes. The emission properties of the original water-soluble form of the molecule were previously found to be selectively quenched in the presence of Hg ions. The fabricated samples were tested with optical waveguide fluorescence spectroscopy by putting them in contact with a 5-?M water solution of Hg ions and recording the emission spectra versus incubation time. The estimate of the limit of detection was 150 nM. A preliminary evaluation of the selectivity of the structure was also performed by using Cd as possible interfering analytes.

Margheri, Giancarlo; Giorgetti, Emilia; Marsili, Paolo; Zoppi, Angela; Lascialfari, Luisa; Cicchi, Stefano

2014-07-01

324

Enhancement of specific capacitance of polyaniline by secondary metal ion doping  

Microsoft Academic Search

In this paper we are reporting secondary metal ion doped polyaniline is chemically synthesized and used for the construction of a redox supercapacitor. The chloride doped polyaniline is chemically synthesized and secondary doping with iron metal cation is studied using 0.5 M concentration of ferric chloride as oxidizing agent. Iron ions doped polyaniline is coated over the indium tin oxide

Arun Kumar Singh; Bhavana Gupta; Rajiv Prakash

2009-01-01

325

Structural, physical and chemical changes induced in metals and alloys exposed to high power ion beams  

Microsoft Academic Search

This review summarizes recent experimental results on metals and alloys irradiated with high power ion beams (HPIB). It was revealed that the thickness of modified layers exceeded the projected ion range by more than two orders of magnitude. The surfaces of irradiated metals exhibit increased microhardness, abrasive and cutting wear resistances. It has been also shown that corrosion resistance increased

A. D. Pogrebnjak; G. E. Remnev; I. E. Kurakin; A. E. Ligachev

1989-01-01

326

Synthesis and evaluation of polyallylamine chelating polymers for the selective removal of metal ions  

SciTech Connect

A major goal of our research program is to develop polymer supported ion specific extraction systems for the removal of actinides and other hazardous metal ions from wastewaters. The advantage of the use of water soluble polymers in metal ion separation processes is that due to the homogeneity of the system, they are expected to provide more rapid exchange kinetics with the target metal ion than ion exchange and chelating resins. Subsequently, the soluble polymer-metal ion complexes can be separated or concentrated using ultrafiltration membrane units. A number of water soluble chelating polymers have been synthesized in our laboratory by functionalization of commercially available polyallylamine with various ligand moieties such as hydroxamates and carboxylates. The ability of these polymers to complex with representative metal ions to give soluble complexes under different pH conditions has been examined. Also the use of these water soluble polymers to remove a number of target metal ions from solutions using ultrafiltration as the mode of metal ion separation will be discussed.

Stark, P.; Jacobs, H.K.; Gopalan, A. [New Mexico State Univ., Las Cruces, NM (United States)] [and others

1996-10-01

327

Metal Ion-Assembled Micro-Collagen Heterotrimers  

PubMed Central

Collagen mimetic peptides (CMPs) provide critical insight into the assembly, stability and structure of the triple helical collagen protein. The majority of natural fibrous collagens are aab or abc heterotrimers, yet few examples of heterotrimeric CMPs have been reported. Previously CMP heterotrimers have only been accessible by total syntheses or by introducing complementary interstrand electrostatic or steric interactions. Here we describe an abc CMP heterotrimer in which each contributing CMP consists of only three amino acids: glycine, proline and 4-hydroxyproline. Assembly of the heterotrimeric triple helix is directed by a combination of metal-ion coordination to set the relative register of the CMPs, and minimization of valence frustration to direct heterotrimerization. Assembly of the four-component mixture is facile and extremely rapid, and equilibration to the abc heterotrimer occurs within a few hours at modestly elevated temperatures. The melting temperatures of the metal-assembled collagen trimers are higher by some 30 °C than the apopeptide assemblies. Two iterations of the design are described, and the outcomes suggest possibilities for designing self-assembling abc and abb heterotrimers. PMID:21590759

LeBruin, Lyndelle Toni; Banerjee, Sunandan; O'Rourke, Bruce Delany; Case, Martin Ashley

2011-01-01

328

Electromigration study of focused ion beam modified metal lines  

SciTech Connect

Focus ion beam (FIB) technology is a commonly used tool for integrated circuit device modification, failure analysis, and a variety of other applications. However, limited reliability data of FIB altered circuit is available. This study describes the electromigration mechanism of FIB-altered Al(Cu-Si)/Ti-layered metal lines. The electromigration failures encountered resulted in Al voids at the anode end of FIB-deposited W and Al{sub 2}Cu precipitates at the cathode end. A higher frequency of Al extrusions was also observed on samples stressed at higher temperatures. These observations indicated that FIB-W was an effective blocking boundary for Al and Cu, and confirmed that Cu does electromigrate before Al. The electromigration mechanism of the FIB-altered line closely resembles the published results from two-level Al/W-line/stud interconnect studies. An activation energy of 0.66 eV, with a current exponent of 1.9 and a lognormal sigma of 0.55, was determined from the kinetic analysis of the FIB-altered metal line.

Lee, J.L.; Yao, D.H. [IBM Microelectronics Div., Essex Junction, VT (United States)

1995-12-31

329

Metal chelates of N,N'-dihydroxyethyl-N,N'-ethylenediaminedisuccinic acid and selected metal ions  

E-print Network

:1 systems. Fe(III) did not form a precipitate beyond a=4. TABLE III Equilibrium Constants for Metal Ion log KMH H 2" the Formation of I:1 H Metal:DHPDDS Chelates* M log KML 1, Mg(II) 2, Ca(I I) 3, Mn(II) 4. Pb (I I) 5, Zn(I I) 6. Co(II) 7..., the negatively charged car- boxylate group of VI has an inductive effect HOCHZCH2+ +CH2CH2OH HNCH2CH2NH OOCCH CHCOO HOOCCH2 CH2COOH VI 25 OOCCH2+ + CH2COO HNCH2CH2NH HOOCCH2CH2 CH7CH2COOH VII TABLE IV Protonation Constants of Selected Ligands...

Hampton, Joan Martiner

2012-06-07

330

The Holifield Radioactive Ion Beam Facility at the Oak Ridge National Laboratory: Present status and future plans  

SciTech Connect

The Holifield Radioactive Ion Beam Facility (HRIBF) is a first generation national user facility for nuclear physics and nuclear astrophysics research with radioactive ion beams (RIBS). The reconfiguration, construction, and equipment-commissioning phases have been completed and the beam development program is in progress. In this article, descriptions of the facility and newly implemented experimental equipment for use in the nuclear and astrophysics programs will be given and an outline of the initial experimental program will be presented. Special target/ion source related problems, endemic to the production of specific short-lived RIBs will be discussed. In addition, plans, which involve either a 200-MeV or a 1-GeV proton-linac driver for a second-generation ISOL facility, will be presented.

Alton, G.D.; Beene, J.R.

1998-03-01

331

The Holifield Radioactive Ion Beam Facility at the Oak Ridge National Laboratory: Present status and future plans  

SciTech Connect

The Holifield Radioactive Ion Beam Facility (HRIBF) is a first generation national user facility for nuclear physics and nuclear astrophysics research with radioactive ion beams (RIBs). The reconfiguration, construction, and equipment commissioning phases have been completed and the beam development program is in progress. In this article, descriptions of the facility and newly implemented experimental equipment for use in the nuclear and astrophysics programs will be given and an outline of the initial experimental program will be presented. Special target ion source related problems, endemic to the production of specific short lived RIBs will be discussed. In addition, plans, which involve either a 200 MeV or a 1 GeV proton linac driver for a second generation ISOL facility, will be presented.

Alton, G.D.; Beene, J.R.

1998-01-01

332

Accurate quantification of radioactive materials by x-ray fluorescence : gallium in plutonium metal /.  

SciTech Connect

Two XRF specimen preparation methods were investigated for quantifying gallium in plutonium metal. Gallium in plutonium was chosen here as an example for demonstrating the efficacy of wavelength dispersive XRF for quantifying radioactive materials. The steps necessary to handle such materials safely will also be discussed. Quantification of plutonium samples by a well-established aqueous specimen preparation method resulted in relative precision and accuracy values of well less than 1%. As an alternative to the aqueous approach, a dried residue method was studied. Quantification of gallium in samples using this method resulted in relative precision and accuracy values an order of magnitude worse, but the method is faster, safer, and generates less waste than the aqueous process. The specimen preparation details and analysis results using each method will be presented here.

Worley, C. G. (Christopher G.)

2002-01-01

333

Fernald`s dilemma: Do we recycle the radioactively contaminated metals, or do we bury them?  

SciTech Connect

During the past five years, a number of U.S. Department of Energy (DOE) funded efforts have demonstrated the technical efficacy of converting various forms of radioactive scrap metal (RSM) into useable products. From the development of large accelerator shielding blocks, to the construction of low level waste containers, technology has been applied to this fabrication process in a safe and stakeholder supported manner. The potential health and safety risks to both workers and the public have been addressed. The question remains; can products be fabricated from RSM in a cost efficient and market competitive manner? This paper presents a methodology for use within DOE to evaluate the costs and benefits of recycling and reusing some RSM, rather than disposing of this RSM in an approved burial site. This life cycle decision methodology, developed by both the Oak Ridge National Laboratory (ORNL) and DOE Fernald is the focus of the following analysis.

Yuracko, K.L.; Hadley, S.W.; Perlack, R.D. [and others

1996-06-01

334

Viscoplasticity of simulated high-level radioactive waste glass containing platinum group metal particles  

NASA Astrophysics Data System (ADS)

The shear rate dependency of the viscosity of three simulated high-level radioactive waste glasses containing 0, 1.2 and 4.5 wt% platinum group metals (PGMs) was examined at a temperature range of 1173-1473 K by a rotating viscometer. Shear stress when the shear rate equals zero, i.e. yield stress, was also measured by capillary method. The viscosity of the glass containing no PGM was shear rate-independent Newtonian fluid. On the other hand, the apparent viscosity of the glasses containing PGMs increased with decreasing shear rate, and nonzero amount of yield stresses were detected from both glasses. The viscosity and yield stress of the glass containing 4.5 wt% PGMs was roughly one to two orders of magnitude greater than the glass containing 1.2 wt% PGMs. These viscoplastic properties were numerically expressed by Casson equation.

Uruga, Kazuyoshi; Usami, Tsuyoshi; Tsukada, Takeshi; Komamine, Satoshi; Ochi, Eiji

2014-09-01

335

Using diastereopeptides to control metal ion coordination in proteins.  

PubMed

Here, we report a previously undescribed approach for controlling metal ion coordination geometry in biomolecules by reorientating amino acid side chains through substitution of L- to D-amino acids. These diastereopeptides allow us to manipulate the spatial orientation of amino acid side chains to alter the sterics of metal binding pockets. We have used this approach to design the de novo metallopeptide, Cd(TRIL12L(D)L16C)(3)(-), which is an example of Cd(II) bound to 3 L-Cys as exclusively trigonal CdS(3), as characterized by a combination of (113)Cd NMR and (111m)Cd PAC spectroscopy. We subsequently show that the physical properties of such a site, such as the high pK(a2) for Cd(II) binding of 15.1, is due to the nature of the coordination number and not the ligating group. Further more this approach allowed for the design of a construct, GRANDL12L(D)L16CL26AL30C, capable of independently binding 2 equivalents of Cd(II) to 2 very similar Cys sites as exclusively 3- and 4-, CdS(3) and CdS(3)O, respectively. Demonstrating that we are capable of controlling the Cd(II) coordination number in these 2 sites solely by varying the nature of a noncoordinating second coordination sphere amino acid, with D-leucine and L-alanine resulting in exclusively 3- and 4-coordinate structures, respectively. Cd(II) was found to selectively bind to the 4-coordinate CdS(3)O site, demonstrating that a protein can be designed that displays metal-binding selectivity based solely on coordination number control and not on the chemical identity of coordinating ligands. PMID:18940928

Peacock, Anna F A; Hemmingsen, Lars; Pecoraro, Vincent L

2008-10-28

336

Metal complexes containing natural and and artificial radioactive elements and their applications.  

PubMed

Recent advances (during the 2007-2014 period) in the coordination and organometallic chemistry of compounds containing natural and artificially prepared radionuclides (actinides and technetium), are reviewed. Radioactive isotopes of naturally stable elements are not included for discussion in this work. Actinide and technetium complexes with O-, N-, N,O, N,S-, P-containing ligands, as well ?-organometallics are discussed from the view point of their synthesis, properties, and main applications. On the basis of their properties, several mono-, bi-, tri-, tetra- or polydentate ligands have been designed for specific recognition of some particular radionuclides, and can be used in the processes of nuclear waste remediation, i.e., recycling of nuclear fuel and the separation of actinides and fission products from waste solutions or for analytical determination of actinides in solutions; actinide metal complexes are also usefulas catalysts forcoupling gaseous carbon monoxide,as well as antimicrobial and anti-fungi agents due to their biological activity. Radioactive labeling based on the short-lived metastable nuclide technetium-99m ((99m)Tc) for biomedical use as heart, lung, kidney, bone, brain, liver or cancer imaging agents is also discussed. Finally, the promising applications of technetium labeling of nanomaterials, with potential applications as drug transport and delivery vehicles, radiotherapeutic agents or radiotracers for monitoring metabolic pathways, are also described. PMID:25061724

Kharissova, Oxana V; Méndez-Rojas, Miguel A; Kharisov, Boris I; Méndez, Ubaldo Ortiz; Martínez, Perla Elizondo

2014-01-01

337

Ligational behavior of Schiff bases towards transition metal ion and metalation effect on their antibacterial activity.  

PubMed

New Schiff bases pyrazine-2-carboxylicacid (phenyl-pyridin-2-yl-methylene)-hydrazide (Hpch-bp) HL(1) and pyrazine-2-carboxylicacid (pyridin-2-ylmethylene)-hydrazide (Hpch-pc) HL(2) derived from condensation of pyrazine carboxylic hydrazide (Hpch) with 2-benzoyl pyridine (bp) or pyridine 2-carbaldehyde (pc) and their transition metal complexes of type ML((1-2)2) have been synthesized, where M=Mn(II), Co(II), Ni(II), Cu(II) and Zn(II). Characterization of ligands and their metal complexes was carried out by elemental analysis, conductimetric studies, magnetic susceptibility, spectroscopic techniques (IR, UV-VIS, NMR, ESR, Mass) and thermogravimetric analysis. The physico-chemical studies revealed octahedral geometry or distorted octahedral geometry around metal ion. These azomethine Schiff base ligands acted as tridentate coordinating through carbonyl, azomethine and pyridine nitrogen present in the ligand. The thermodynamic and thermal properties of the complexes have been investigated and it was observed on the basis of these studies that thermal stability of complexes follows the order Mnmetal ions. The trend of growth inhibition in the complexes was found to be in the order: Cu>Mn>Ni>Co>Zn. PMID:22813991

Devi, Jai; Batra, Nisha; Malhotra, Rajesh

2012-11-01

338

An artificial tongue fluorescent sensor array for identification and quantitation of various heavy metal ions.  

PubMed

Herein, a small-molecule fluorescent sensor array for rapid identification of seven heavy metal ions was designed and synthesized, with its sensing mechanism mimicking that of a tongue. The photoinduced electron transfer and intramolecular charge transfer mechanism result in combinatorial interactions between sensor array and heavy metal ions, which lead to diversified fluorescence wavelength shifts and emission intensity changes. Upon principle component analysis (PCA), this result renders clear identification of each heavy metal ion on a 3D spatial dispersion graph. Further exploration provides a concentration-dependent pattern, allowing both qualitative and quantitative measurements of heavy metal ions. On the basis of this information, a "safe-zone" concept was proposed, which provides rapid exclusion of versatile hazardous species from clean water samples based on toxicity characteristic leaching procedure standards. This type of small-molecule fluorescent sensor array could open a new avenue for multiple heavy metal ion detection and simplified water quality analysis. PMID:25144824

Xu, Wang; Ren, Changliang; Teoh, Chai Lean; Peng, Juanjuan; Gadre, Shubhankar Haribhau; Rhee, Hyun-Woo; Lee, Chi-Lik Ken; Chang, Young-Tae

2014-09-01

339

Humic Ion-Binding Model VI: An Improved Description of the Interactions of Protons and Metal Ions with Humic Substances  

Microsoft Academic Search

Humic Ion-Binding Model VI, a discrete site\\/electrostatic model of the interactions of protons and metals with fulvic and humic acids, is applied to 19 sets of published data for proton binding, and 110 sets for metal binding. Proton binding is described with a site density, two median intrinsic equilibrium constants, two parameters defining the spread of equilibrium constants around the

Edward Tipping

1998-01-01

340

Functional nucleic acid-based sensors for heavy metal ion assays.  

PubMed

Heavy metal contaminants such as lead ions (Pb(2+)), mercury ions (Hg(2+)) and silver ions (Ag(+)) can cause significant harm to humans and generate enduring bioaccumulation in ecological systems. Even though a variety of methods have been developed for Pb(2+), Hg(2+) and Ag(+) assays, most of them are usually laborious and time-consuming with poor sensitivity. Due to their unique advantages of excellent catalytic properties and high affinity for heavy metal ions, functional nucleic acids such as DNAzymes and aptamers show great promise in the development of novel sensors for heavy metal ion assays. In this review, we summarize the development of functional nucleic acid-based sensors for the detection of Pb(2+), Hg(2+) and Ag(+), and especially focus on two categories including the direct assay and the amplification-based assay. We highlight the emerging trends in the development of sensitive and selective sensors for heavy metal ion assays as well. PMID:25356810

Zhu, Guichi; Zhang, Chun-Yang

2014-11-10

341

Sunflower stalks as adsorbents for the removal of metal ions from wastewater  

SciTech Connect

Sunflower stalks as adsorbents for the removal of metal ions such as copper, cadmium, zinc, and chromium ions in aqueous solutions were studied with equilibrium isotherms and kinetic adsorptions. The maximum adsorptions of four heavy metals are 29.3 mg/g (Cu{sup 2+}), 30.73 mg/g (Zn{sup 2+}), 42.18 mg/g (Cd{sup 2+}), and 25.07 mg/g (Cr{sup 3+}), respectively. Particle sizes of sunflower stalks affected the adsorption of metal ions; the finer size of particles showed better adsorption to the ions. Temperature also plays an interesting role in the adsorption of different metal ions. Copper, zinc, and cadmium exhibited lower adsorption on sunflower stalks at higher temperature, while chromium showed the opposite phenomenon. The adsorption rates of copper, cadmium, and chromium are quite rapid. Within 60 min of operation about 60--80% of these ions were removed from the solutions.

Sun, G.; Shi, W. [Univ. of California, Davis, CA (United States). Div. of Textiles and Clothing] [Univ. of California, Davis, CA (United States). Div. of Textiles and Clothing

1998-04-01

342

METAL INTERACTIONS AT SULFIDE MINERAL SURFACES: PART 3, METAL AFFINITIES IN SINGLE AND MULTIPLE ION ADSORPTION REACTIONS  

EPA Science Inventory

Adsorption reactions of both single ions and multiple ion mixtures with sulfide minerals (chalcocite, galena, pyrite, and sphalerite) were investigated in the metal concentration range of 0.0001 to 0.00001 M. Chromium (III), iron (III), barium (II), cadmium (II), copper (II), nic...

343

Treatment of waters polluted with radioactive elements and heavy metals by means of a laboratory passive system  

Microsoft Academic Search

Waters polluted with toxic heavy metals, radioactive elements, arsenic and sulphates were efficiently treated by means of a laboratory-scale passive system consisting of an anaerobic cell and a constructed wetland. These waters were polluted in a stream receiving leachates from an operating copper tailings dam and other effluents from man-induced activities at the area of Vromos Bay in Bulgaria. The

S. N. Groudev; S. G. Bratcova; K. Komnitsas

1999-01-01

344

RADIOACTIVE TRACER STUDIES ON THE CORROSION RESISTANCE OF SOLID SOLUTIONS OF METALS. II. THE SYSTEM Mg-Cd  

Microsoft Academic Search

A study was made of the formation of a surface layer on Mg--Cd alloys in ; O.1N HâSOâ at room temperature. The radioactive isotope Rb⁸⁶ ; was used to determine the depth of the micropores at the metal and alloy surfaces. ; As a result the following mean values for the depths of the micropores before ; corrosion were obtained:

N. N. Gratsianskii; P. F. Kaluzhnaya

1959-01-01

345

Affinity of radioactive cesium and strontium for illite and smectite clay in the presence of groundwater ions  

SciTech Connect

Sorption behavior of hazardous nuclides such as {sup 137}Cs and {sup 90}Sr onto illite and smectite clay was studied in the presence of major groundwater ions (Ca{sup 2+}, Mg{sup 2+}, K{sup +}, Na{sup +} and HCO{sub 3}{sup -}). Illite and smectite clay can selectively sorb small hydrated Cs{sup +} ion in the presence of groundwater cations except K{sup +} ion. In contrast, sorption of larger and stable hydrated Sr{sup 2+} ion onto illite and smectite clay is highly competed by background groundwater cations. The results of this study indicate that the transport of {sup 137}Cs in geologic barrier of a radioactive waste repository would be greatly retained by illite and smectite clay, and that the fate of {sup 90}Sr would be significantly controlled by ionic strength of groundwater cations and bicarbonate ion as a complex agent. 29 refs., 6 figs., 4 tabs.

Jeong, C.H.; Kim, C.S. [Korea Atomic Energy Research Inst., Taejeon (Korea, Republic of); Kim, S.J. [Seoul National Univ. (Korea, Republic of); Park, S.W. [Keimyung Univ., Taegu (Korea, Republic of)

1996-10-01

346

Conditions of accumulation of radioactive metals in the process of differentiation of ultrabasic alkaline-carbonatite rock associations  

NASA Astrophysics Data System (ADS)

The distribution of radioactive elements in alkaline rocks from Polar Siberia and Ukraine shows that U and Th are markedly concentrated in carbonatite complex and nepheline syenite as final products of magma fractionation. Peralkaline nepheline syenites from Polar Siberia are characterized by very high contents of radioactive elements, which are close to the economic level. Radioactive elements are also concentrated in rocks of the carbonatite complex. For example, some soevites contain up to 294 × 10-4%U and 916 × 10-4% Th. In late dolomite carbonatites, the contents of radioactive elements are appreciably lower. The Th/U ratio in alkaline rocks of Polar Siberia is close to the chondrite value in primary high-Mg rocks and increases in late derivatives: phoscorite, calcite and dolomite carbonatites. The main amount of radioactive elements is contained in rare-metal accessory minerals: perovskite, pyrochlore, calzirtite, and apatite. Rock-forming minerals are distinguished by very low concentrations of radioactive elements. In alkaline series of the Chernigovka massif (Ukraine), U and Th also accumulate in the course of crystal fractionation, especially in phoscorites from the carbonatite complex. Mantle xenoliths and alkaline rocks from Ukraine reveal uranium specialization. Most likely, the discrepancy in fractionation of radioactive elements between Polar Siberia and Ukraine is caused by different geodynamic regimes of these provinces. The Mesozoic alkaline magmatism of Polar Siberia is a part of the Siberian superplume, whereas the Proterozoic alkaline complex in Ukraine is related to subduction of the oceanic crust.

Kogarko, L. N.

2014-07-01

347

Attempted Removal of Metal Ions and Subsequent Vacuum Pyrolysis of Barks from Five Species of Softwoods  

Microsoft Academic Search

Samples of whole bark were collected from sub-alpine fir, Engelmann spruce, Douglas fir, western larch and lodgepole pine. Attempts to remove metal ions from the barks by ion exchange with dilute acid at room temperature showed that up to one third of these ions (especially calcium) are inaccessable to aqueous acid and hence not removed. The barks were subjected to

H.-X. Qiu; G. N. Richards

1989-01-01

348

Surface modification of medical metals by ion implantation of silver and copper  

Microsoft Academic Search

Implant related infections remain a concern in modern surgery. Surface modification is an effective way to reduce the occurrence of these complications. Of various techniques, ion implantation shows promise. In the present work, silver and copper were ion implanted separately, into three typical medical metals, namely 317L stainless steel, titanium, and Ti–Al–Nb by a MEVVA ion source machine at various

Y. Z. Wan; S. Raman; F. He; Y. Huang

2007-01-01

349

An exploratory program for using hydrous metal oxide ion exchangers as Fischer-Tropsch catalysts  

Microsoft Academic Search

The purpose of this program is to investigate the potential of hydrous metal oxide (HMO) ion exchangers, invented at Sandia National Laboratories, as Fischer-Tropsch (F-T) catalysts. Metals known to be active in F-T synthesis (e.g. Fe, Co) were ion exchanged on hydrous metal oxide supports. Although HMO catalysts based on Zr, Nb, and Ta have been investigated in direct coal

A. W. Lynch; R. G. Dosch; A. G. Sault

1990-01-01

350

Status of Tokai Radioactive Ion Accelerator Complex and Feasibility Study for Transfer Reactions Using Low-Energy RNB  

NASA Astrophysics Data System (ADS)

An ISOL-based radioactive nuclear beam facility, Tokai Radioactive Ion Accelerator Complex (TRIAC), has been jointly constructed by High Energy Accelerator Research Organization (KEK) and Japan Atomic Energy Agency (JAEA). The facility started to provide RNBs for experiments in 2005. RNBs, including fission fragments with energies up to 1.1 MeV/nucleon, are available. The experiments were performed with accelerated 8Li beams of various energies. Current status of the equipments and preliminary results on these experimental studies are presented.

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

2007-05-01

351

Metal-semiconductor-metal ion-implanted Si waveguide photodetectors for C-band operation.  

PubMed

Metal-semiconductor-metal Si waveguide photodetectors are demonstrated with responsivities of greater than 0.5 A/W at a wavelength of 1550 nm for a device length of 1mm. Sub-bandgap absorption in the Si waveguide is achieved by creating divacancy lattice defects via Si(+) ion implantation. The modal absorption coefficient of the ion-implanted Si waveguide is measured to be ? 185 dB/cm, resulting in a detector responsivity of ? 0.51 A/W at a 50 V bias. The frequency response of a typical 1mm-length detector is measured to be 2.6 GHz, with simulations showing that a frequency response of 9.8 GHz is achievable with an optimized contact configuration and bias voltage of 15 V. Due to the ease with which these devices can be fabricated, and their potential for high performance, these detectors are suitable for various applications in Si-based photonic integrated circuits. PMID:24787805

Souhan, Brian; Grote, Richard R; Driscoll, Jeffrey B; Lu, Ming; Stein, Aaron; Bakhru, Hassaram; Osgood, Richard M

2014-04-21

352

The ligand-promoted mobilisation of metal ions from mineral surfaces  

Microsoft Academic Search

Many metals such as Fe, Mo, Cu, Zn etc have been identified as essential micronutrients for plants and microorganisms. These metals have to be mobilised from mineral surfaces in contact with crustal fluids in order to be available to living cells. Many studies have shown the importance of chelation in the mobilisation of metal ions into these fluids. The ligand-promoted

C. V. Putnis

2003-01-01

353

Method and apparatus for providing negative ions of actinide-metal hexafluorides  

Microsoft Academic Search

This invention relates to a novel method and a novel generator, or source, for providing gaseous negative ions of selected metal hexafluorides. The method is summarized as follows: in an evacuated zone, reacting gaseous fluorine with an actinide-metal body selected from the group consisting of uranium, plutonium, neptunium, and americium to convert at least part of the metal to the

R. N. Compton; P. W. Reinhardt; W. R. Garrett

1978-01-01

354

Development of a metal recovery process from Li-ion battery wastes  

Microsoft Academic Search

A process for the recovery of lithium and cobalt from the waste of lithium ion batteries using sulfuric acid and hydrogen peroxide was proposed, and metal leaching performance was investigated. The proposed procedure consisted of mechanical separation of metal-containing particles and a chemical leaching process. The effects of leaching agent, of the size of metal-bearing particles, and of incineration as

Shun Myung Shin; Nak Hyoung Kim; Jeong Soo Sohn; Dong Hyo Yang; Young Han Kim

2005-01-01

355

Evaluation of the possibility of contamination of sea water by metal ions present in fuel oil  

Microsoft Academic Search

In this study, the reactivity of metal ions that exist in fuel oil with some ligands present either in sea water (inorganic ligands) or in fuel oil (mercaptans and organic acids) were compared based on their formation constants. The values of the formation constants of the metals with the main ligands in water are known. The complexation of the metals

C. M. M. A. Portella; M. L. B. Tristão; J. Felcman

2006-01-01

356

FOREWORD: Collision Processes of Metallic Ions in Fusion Plasmas  

NASA Astrophysics Data System (ADS)

On May 16-18, 1990, an Advisory Group Meeting on "Atomic and Molecular Data for Metallic Impurities in Fusion Plasmas" was organized by the Atomic and Molecular Data Unit of the International Atomic Energy Agency and held in Vienna, Austria. The objectives of the Meeting were to review the status of atomic collision data for the most important fusion plasma metallic impurities (Ti, Cr, Fe and Ni), to identify the gaps in the database in relation to the data needs of the current fusion research and reactor design work, and to report on recent original cross section calculations and measurements for the collision processes of these ions. The scope of the meeting included the following collision processes: (a) Electron collisions with Tiq+, Crq+, Feq+ and Niq+ ions (excitation, ionization, radiative and dielectronic recombination); (b) Collisions of Tiq+, Crq+, Feq+ and Niq+ ions with H, H2, and He (total and state-selective electron capture, excitation, ionization and dissociative processes with H2). The meeting was attended by fifteen participants covering almost uniformly the various collision processes, energy ranges and research methods (theoretical and experimental). In the area of electron-ion collision processes, extensive reviews of the current research and cross section data situation have been presented by Y Hahn (on radiative and dielectronic recombination), D Gregory (on excitation) and A Muller (on ionization). Contributions regarding the cross sections and/or reaction rates of many specific processes were given by N Badnell, K Berrington, M Bitter, R E H Clark, A Muller and V P Shevelko. V A Abramov provided a comparison of the electron-impact excitation data, evaluated by several groups, and demonstrated their consistency in the majority of analyzed cases. In the area of heavy-particle collision processes, the research and database situation was reviewed by H B Gilbody. Original cross section information for specific heavy-particle collision processes was presented by H Cederquist, W Fritsch, R E Olson, K Katsonis and G L Yudin. The present Topical Issue of Physica Scripta contains the contributions presented at the meeting with the exception of the presentation of V A Abramov. The reports of the Working Groups, established at the meeting to critically evaluate the available data and to identify the gaps in the database, are also included in this volume. An appropriate introductory comment by the Guest Editor on the impurity sources and the role of impurity collision processes in fusion plasmas is also added. On behalf of the International Atomic Energy Agency, I take this opportunity to thank the participants of the Advisory Group Meeting for their dedicated work and valuable contribution to this international endeavour and for their co-operativeness in the course of preparation of this volume.

Janev, R. K.

1991-01-01

357

A New Strategy to Stabilize Oxytocin in Aqueous Solutions: I. The Effects of Divalent Metal Ions and Citrate Buffer  

Microsoft Academic Search

In the current study, the effect of metal ions in combination with buffers (citrate, acetate, pH 4.5) on the stability of\\u000a aqueous solutions of oxytocin was investigated. Both monovalent metal ions (Na+ and K+) and divalent metal ions (Ca2+, Mg2+, and Zn2+) were tested all as chloride salts. The effect of combinations of buffers and metal ions on the stability of

Christina Avanti; Jean-Pierre Amorij; Dewi Setyaningsih; Andrea Hawe; Wim Jiskoot; Jan Visser; Alexej Kedrov; Arnold J. M. Driessen; Wouter L. J. Hinrichs; Henderik W. Frijlink

2011-01-01

358

Impact of Protein-Metal Ion Interactions on the Crystallization of Silk Fibroin Protein  

NASA Astrophysics Data System (ADS)

Proteins can easily form bonds with a variety of metal ions, which provides many unique biological functions for the protein structures, and therefore controls the overall structural transformation of proteins. We use advanced thermal analysis methods such as temperature modulated differential scanning calorimetry and quasi-isothermal TMDSC, combined with Fourier transform infrared spectroscopy, and scanning electron microscopy, to investigate the protein-metallic ion interactions in Bombyx mori silk fibroin proteins. Silk samples were mixed with different metal ions (Ca^2+, K^+, Ma^2+, Na^+, Cu^2+, Mn^2+) with different mass ratios, and compared with the physical conditions in the silkworm gland. Results show that all metallic ions can directly affect the crystallization behavior and glass transition of silk fibroin. However, different ions tend to have different structural impact, including their role as plasticizer or anti-plasticizer. Detailed studies reveal important information allowing us better to understand the natural silk spinning and crystallization process.

Hu, Xiao; Lu, Qiang; Kaplan, David; Cebe, Peggy

2009-03-01

359

Computational scheme for the prediction of metal ion binding by a soil fulvic acid  

USGS Publications Warehouse

The dissociation and metal ion binding properties of a soil fulvic acid have been characterized. Information thus gained was used to compensate for salt and site heterogeneity effects in metal ion complexation by the fulvic acid. An earlier computational scheme has been modified by incorporating an additional step which improves the accuracy of metal ion speciation estimates. An algorithm is employed for the prediction of metal ion binding by organic acid constituents of natural waters (once the organic acid is characterized in terms of functional group identity and abundance). The approach discussed here, currently used with a spreadsheet program on a personal computer, is conceptually envisaged to be compatible with computer programs available for ion binding by inorganic ligands in natural waters.

Marinsky, J.A.; Reddy, M.M.; Ephraim, J.H.; Mathuthu, A.S.

1995-01-01

360

Metal Ion Concentrations in Body Fluids after Implantation of Hip Replacements with Metal-on-Metal Bearing - Systematic Review of Clinical and Epidemiological Studies  

PubMed Central

Introduction The use of metal-on-metal (MoM) total hip arthroplasty (THA) increased in the last decades. A release of metal products (i.e. particles, ions, metallo-organic compounds) in these implants may cause local and/or systemic adverse reactions. Metal ion concentrations in body fluids are surrogate measures of metal exposure. Objective To systematically summarize and critically appraise published studies concerning metal ion concentrations after MoM THA. Methods Systematic review of clinical trials (RCTs) and epidemiological studies with assessment of metal ion levels (cobalt, chromium, titanium, nickel, molybdenum) in body fluids after implantation of metalliferous hip replacements. Systematic search in PubMed and Embase in January 2012 supplemented by hand search. Standardized abstraction of pre- and postoperative metal ion concentrations stratified by type of bearing (primary explanatory factor), patient characteristics as well as study quality characteristics (secondary explanatory factors). Results Overall, 104 studies (11 RCTs, 93 epidemiological studies) totaling 9.957 patients with measurement of metal ions in body fluids were identified and analyzed. Consistently, median metal ion concentrations were persistently elevated after implantation of MoM-bearings in all investigated mediums (whole blood, serum, plasma, erythrocytes, urine) irrespective of patient characteristics and study characteristics. In several studies very high serum cobalt concentrations above 50 µg/L were measured (detection limit typically 0.3 µg/L). Highest metal ion concentrations were observed after treatment with stemmed large-head MoM-implants and hip resurfacing arthroplasty. Discussion Due to the risk of local and systemic accumulation of metallic products after treatment with MoM-bearing, risk and benefits should be carefully balanced preoperatively. The authors support a proposed „time out“ for stemmed large-head MoM-THA and recommend a restricted indication for hip resurfacing arthroplasty. Patients with implanted MoM-bearing should receive regular and standardized monitoring of metal ion concentrations. Further research is indicated especially with regard to potential systemic reactions due to accumulation of metal products. PMID:23950923

Hartmann, Albrecht; Hannemann, Franziska; Lutzner, Jorg; Seidler, Andreas; Drexler, Hans; Gunther, Klaus-Peter; Schmitt, Jochen

2013-01-01

361

High Power Molten Targets for Radioactive Ion Beam Production: from Particle Physics to Medical Applications  

E-print Network

Megawatt-class molten targets, combining high material densities and good heat transfer properties are being considered for neutron spallation sources, neutrino physics facilities and radioactive ion beam production. For this last category of facilities, in order to cope with the limitation of long diffusion times affecting the extraction of short-lived isotopes, a lead-bismuth eutectic (LBE) target loop equipped with a diffusion chamber has been proposed and tested offline during the EURISOL design study. To validate the concept, a molten LBE loop is now in the design phase and will be prototyped and tested on-line at CERN-ISOLDE. This concept was further extended to an alternative route to produce 1013 18Ne/s for the Beta Beams, where a molten salt loop would be irradiated with 7 mA, 160 MeV proton beam. Some elements of the concept have been tested by using a molten fluoride salt static unit at CERNISOLDE. The investigation of the release and production of neon isotopes allowed the measurement of the diffu...

De Melo Mendonca, T M

2014-01-01

362

Ion exchangers in radioactive waste management VII. Radiotracer studies on adsorption of Ba(II) and Sr(II) ions on hydrous thorium oxide  

Microsoft Academic Search

Hydrous thorium oxide (HTO) was synthesized and laboratory study was conducted to address its applicability for decontamination of barium and strontium ions from radioactive liquid wastes using radiotracer technique. The adsorption of Ba(II) and Sr(II) on HTO has been investigated as a function of pH, concentration and temperature of the adsorptive solution and the results obtained show that these parameters

S. P. Mishra; D. Tiwary

1995-01-01

363

Glycan chains modulate prion protein binding to immobilized metal ions.  

PubMed

PrP(c) is the normal isoform of the prion protein which can be converted into PrP(Sc), the pathology-associated conformer in prion diseases. It contains two N-linked glycan chains attached to the C-proximal globular domain. While the biological functions of PrP(c) are still unknown, its ability to bind Cu(2+) is well documented. The main Cu(2+)-binding sites are located in the N-proximal, unstructured region of the molecule. Here we report that PrP(c) glycans influence the capacity of PrP(c) from sheep brain or cultured Rov cells to bind IMAC columns loaded with Cu(2+) or Co(2+). Using different anti-PrP antibodies and PrP(c) glycosylation mutants, we show that the full length non-glycosylated form of PrP(c) has a higher binding efficiency for column-bound Cu(2+) and Co(2+) than the corresponding glycosylated form. Our findings raise the possibility that the accessibility of the PrP(c) metal ion-binding sites might be controlled by the glycan chains. PMID:17293006

Moudjou, Mohammed; Bernard, Julie; Sabuncu, Elifsu; Langevin, Christelle; Laude, Hubert

2007-04-01

364

Radioactive ion beams produced by neutron-induced fission at ISOLDE  

E-print Network

The production rates of neutron-rich fission products for the next-generation radioactive beam facility EURISOL are mainly limited by the maximum amount of power deposited by protons in the target. An alternative approach is to use neutron beams to induce fission in actinide targets. This has the advantage of reducing: the energy deposited by the proton beam in the target; contamination from neutron-deficient isobars that would be produced by spallation; and mechanical stress on the target. At ISOLDE CERN, tests have been made on standard ISOLDE actinide targets using fast neutron bunches produced by bombarding thick, high-Z metal converters with 1 and 1.4 GeV proton pulses. This paper reviews the first applications of converters used at ISOLDE. It highlights the different geometries and the techniques used to compare fission yields produced by the proton beam directly on the target with neutron-induced fission. Results from the six targets already tested, namely UC2/graphite and ThO2 targets with tungsten an...

Catherall, R; Gilardoni, S S; Köster, U

2003-01-01

365

A gas-jet transport and catcher technique for on-line production of radioactive ion beams using an electron cyclotron resonance ion-source.  

PubMed

Radioactive ion beams (RIB) have been produced on-line, using a gas-jet recoil transport coupled Electron Cyclotron Resonance (ECR) ion-source at the VECC-RIB facility. Radioactive atoms?molecules carried through the gas-jet were stopped in a catcher placed inside the ECR plasma chamber. A skimmer has been used to remove bulk of the carrier gas at the ECR entrance. The diffusion of atoms?molecules through the catcher has been verified off-line using stable isotopes and on-line through transmission of radioactive reaction products. Beams of (14)O (71 s), (42)K (12.4 h), (43)K (22.2 h), and (41)Ar (1.8 h) have been produced by bombarding nitrogen and argon gas targets with proton and alpha particle beams from the K130 cyclotron at VECC. Typical measured intensity of RIB at the separator focal plane is found to be a few times 10(3) particles per second (pps). About 3.2 × 10(3) pps of 1.4 MeV (14)O RIB has been measured after acceleration through a radiofrequency quadrupole linac. The details of the gas-jet coupled ECR ion-source and RIB production experiments are presented along with the plans for the future. PMID:23556809

Naik, V; Chakrabarti, A; Bhattacharjee, M; Karmakar, P; Bandyopadhyay, A; Bhattacharjee, S; Dechoudhury, S; Mondal, M; Pandey, H K; Lavanyakumar, D; Mandi, T K; Dutta, D P; Kundu Roy, T; Bhowmick, D; Sanyal, D; Srivastava, S C L; Ray, A; Ali, Md S

2013-03-01

366

A gas-jet transport and catcher technique for on-line production of radioactive ion beams using an electron cyclotron resonance ion-source  

NASA Astrophysics Data System (ADS)

Radioactive ion beams (RIB) have been produced on-line, using a gas-jet recoil transport coupled Electron Cyclotron Resonance (ECR) ion-source at the VECC-RIB facility. Radioactive atoms/molecules carried through the gas-jet were stopped in a catcher placed inside the ECR plasma chamber. A skimmer has been used to remove bulk of the carrier gas at the ECR entrance. The diffusion of atoms/molecules through the catcher has been verified off-line using stable isotopes and on-line through transmission of radioactive reaction products. Beams of 14O (71 s), 42K (12.4 h), 43K (22.2 h), and 41Ar (1.8 h) have been produced by bombarding nitrogen and argon gas targets with proton and alpha particle beams from the K130 cyclotron at VECC. Typical measured intensity of RIB at the separator focal plane is found to be a few times 103 particles per second (pps). About 3.2 × 103 pps of 1.4 MeV 14O RIB has been measured after acceleration through a radiofrequency quadrupole linac. The details of the gas-jet coupled ECR ion-source and RIB production experiments are presented along with the plans for the future.

Naik, V.; Chakrabarti, A.; Bhattacharjee, M.; Karmakar, P.; Bandyopadhyay, A.; Bhattacharjee, S.; Dechoudhury, S.; Mondal, M.; Pandey, H. K.; Lavanyakumar, D.; Mandi, T. K.; Dutta, D. P.; Kundu Roy, T.; Bhowmick, D.; Sanyal, D.; Srivastava, S. C. L.; Ray, A.; Ali, Md. S.

2013-03-01

367

Trace metal and major ion interactions in aquatic animals  

Microsoft Academic Search

In reviewing studies of trace metal uptake over the last 30 years, evidence is sought for specific mechanisms controlling transepithelial metal uptake or loss, and their possible relationship with pumps controlling the regulation of physiologically-important electroytes. There is evidence of zinc regulation in some crustaceans. However, the widespread occurrence of specific transepithelial regulatory mechanisms for trace metals is unlikely. Metal

David A. Wright

1995-01-01

368

Synthesis and characterization of lanthanum dicarbide-carbon targets for radioactive ion beams generation via the carbothermal reaction  

Microsoft Academic Search

In this study, we report the synthesis procedure for the attainment of thin pellets composed of lanthanum dicarbide (LaC2) grains and graphite, as a candidate material for the production of targets for the generation of radioactive ion beams (RIBs). The samples were obtained by thermal treatment of green pellets of lanthanum oxide or lanthanum oxalate (La2O3 and La2(C2O4)3, respectively) mixed

S. Carturan; M. Tonezzer; L. Piga; P. Zanonato; P. Colombo; A. Andrighetto; L. Biasetto; P. Di Bernardo; G. Maggioni; F. Gramegna; G. Prete

2007-01-01

369

Biosorption/heavy metal ions from industrial/mining waste waters. Technical completion report  

SciTech Connect

The interactions between algal biomass and various metal ions were investigated. For most of the ions examined, uptake is dependent upon pH, with cations bound most strongly above pH 4 and complex anions bound most strongly at lower pH values. Heat treatment of the biomass was found to have little effect on binding capacity. As with other ion-exchange matrices, the extent of metal-ion removal is strongly influenced by the solution composition - in particular, the pressure of competing ligands.

Darnall, D.

1986-06-01

370

Metal cation binding to gas-phase pentaalanine: divalent ions restructure the complex.  

PubMed

Ion-neutral complexes of pentaalalanine with several singly- and doubly charged metal ions are examined using conformation analysis by infrared multiple photon dissociation (IRMPD) spectroscopy and density functional theory (DFT) computations. The infrared spectroscopy in the 1500-1800 cm(-1) region is found to be conformationally informative; in particular, the frequency of the C?O stretching mode of the terminal carboxyl group is diagnostic for hydrogen bonding of the terminal hydroxyl. The doubly charged alkaline earth metal ions (Ca(2+) and Ba(2+)) enforce a highly structured chelation shell around the metal ion, with six strongly bound Lewis-basic chelation sites, and no hydroxyl hydrogen bonding. With the more weakly binding alkali metal ions (Na(+), K(+), and Cs(+)), structures with intramolecular hydrogen bonds are more favorable, leading to dominance of conformations with lower degrees of metal ion chelation. The favored coordination mode correlates with ionic charge and binding strength but is not related to the ionic radius of the metal ion. PMID:22928606

Dunbar, Robert C; Steill, Jeffrey D; Polfer, Nicolas C; Oomens, Jos

2013-02-14

371

Process for carbonaceous material conversion and recovery of alkali metal catalyst constituents held by ion exchange sites in conversion residue  

DOEpatents

In a coal gasification operation or similar conversion process carried out in the presence of an alkali metal-containing catalyst wherein solid particles containing alkali metal residues are produced, alkali metal constituents are recovered for the particles by contacting or washing them with an aqueous solution containing calcium or magnesium ions in an alkali metal recovery zone at a low temperature, preferably below about 249.degree. F. During the washing or leaching process, the calcium or magnesium ions displace alkali metal ions held by ion exchange sites in the particles thereby liberating the ions and producing an aqueous effluent containing alkali metal constituents. The aqueous effluent from the alkali metal recovery zone is then recycled to the conversion process where the alkali metal constituents serve as at least a portion of the alkali metal constituents which comprise the alkali metal-containing catalyst.

Sharp, David W. (Seabrook, TX)

1980-01-01

372

Plastic flow produced by single ion impacts on metals.  

SciTech Connect

Single ion impacts have been observed using in situ transmission electron microscopy and video recording with a time resolution of 33 milliseconds. Gold was irradiated at 50 K and room temperature. Single ion impacts produce holes, modify existing holes, and extrude material into the initial specimen hole and holes formed by other ion impacts. The same behavior is observed at both temperatures. At both temperatures, ion impacts result in craters and ejected material. Ion impacts produce more small craters than large ones for all ion masses, while heavier mass ions produce more and larger craters than lighter mass ions. This comparison is affected by the ion energy. As the energy of an ion is increased, the probability for deposition near the surface decreases and fewer craters are formed. For a given ion mass, crater production depends on the probability for displacement cascade production in the near surface region. Crater and holes are stable at room temperature, however, ion impacts near an existing crater may cause flow of material into the crater either reshaping or annihilating it. Holes and craters result from the explosive outflow of material from the molten zone of near-surface cascades. The outflow may take the form of molten material, a solid lid or an ejected particle. The surface is a major perturbation on displacement cascades resulting from ion impacts.

Birtcher, R. C.

1998-10-30

373

Chromium and cobalt ion concentrations in blood and serum following various types of metal-on-metal hip arthroplasties  

PubMed Central

Background and purpose Widely different metal ion concentrations in blood and serum have been reported with metal-on-metal (MoM) implants. We reviewed the literature on blood and serum ion concentrations of chromium (Cr) and cobalt (Co) following various MoM hip arthroplasties. Methods Studies were searched for in the Medline database, Embase, and the Cochrane Database of Systematic Reviews. Highest mean or median ion concentrations of Cr and Co after a minimum of 1 year of follow-up were extracted and grouped according to sample- and articulation type, and average values were calculated. Results 43 studies were included and 16 different MoM implants were identified. For the different types of bearings, average ion concentrations and range were calculated from the mean or median ion concentration. The average Cr concentration ranged between 0.5 and 2.5 ?g/L in blood and between 0.8 and 5.1 ?g/L in serum. For Co, the range was 0.7–3.4 ?g/L in blood and 0.3–7.5 ?g/L in serum. Interpretation When the average blood ion concentrations calculated for the different implants, together with the concentrations measured in the individual studies, were compared with the upper acceptable limit for Cr and Co in blood, no clear pattern was recognized. Furthermore, we were unable to detect any clear difference in ion concentrations between different types of implants (THA and resurfacing). PMID:23594249

2013-01-01

374

Effects of Alkali Metal Ion Cationization on Fragmentation Pathways of Triazole-Epothilone  

NASA Astrophysics Data System (ADS)

The collisionally activated dissociation mass spectra of the protonated and alkali metal cationized ions of a triazole-epothilone analogue were studied in a Fourier transform ion cyclotron resonance mass spectrometer. The fragmentation pathway of the protonated ion was characterized by the loss of the unit of C3H4O3. However, another fragmentation pathway with the loss of C3H2O2 was identified for the complex ions with Na+, K+, Rb+, and Cs+. The branching ratio of the second pathway increases with the increment of the size of alkali metal ions. Theoretical calculations based on density functional theory (DFT) method show the difference in the binding position of the proton and the metal ions. With the increase of the radii of the metal ions, progressive changes in the macrocycle of the compound are induced, which cause the corresponding change in their fragmentation pathways. It has also been found that the interaction energy between the compound and the metal ion decreases with increase in the size of the latter. This is consistent with the experimental results, which show that cesiated complexes readily eject Cs+ when subject to collisions.

Duan, Xiyan; Luo, Guoan; Chen, Yue; Kong, Xianglei

2012-06-01

375

Asymmetrical hip loading correlates with metal ion levels in patients with metal-on-metal hip resurfacing during sit-to-stand.  

PubMed

The occurrence of pseudotumours following metal-on-metal hip resurfacing arthroplasty (MoMHRA) has been associated with high serum metal ion levels and consequently higher than normal bearing wear. Measuring ground reaction force is a simple method of collecting information on joint loading during a sit-to-stand (STS). We investigated vertical ground reaction force (VGRF) asymmetry during sit-to-stand for 12 MoMHRA patients with known serum metal ion levels. Asymmetry was assessed using two methods: a ratio of VGRF for implanted/unimplanted side and an absolute symmetry index (ASI). It was found that subjects with high serum metal ion levels preferentially loaded their implanted sides. The difference between the two groups was most apparent during the first 22% of STS. VGRF ratio showed significant and strong correlation with serum metal ion levels (Spearman's rho = 0.8, p = 0.003). These results suggest that individual activity patterns play a role in the wear of MoMHRA and preferential loading of an implanted limb during the initiation of motion may increase the wear of metal-on-metal hip replacements. PMID:24474415

Mellon, Stephen; Grammatopoulos, George; Pandit, Hemant; Murray, David W; Gill, Harinderjit S

2014-01-01

376

Negative ion photoelectron spectroscopic studies of transition metal cluster  

Microsoft Academic Search

The studies reported in this thesis were performed using a negative ion photoelectron spectrometer consisting of a cold cathode DC discharge ion source, a flowing afterglow ion-molecule reactor, a magnetic sector mass analyzer, an argon ion laser for photodetachment and a hemispherical electron kinetic energy analyzer and microchannel plate detector for photoelectron spectrum generation. The 476.5 nm (2.601 eV), 488.0

Timothy Paul Marcy

1999-01-01

377

Sequential phosphoproteomic enrichment through complementary metal-directed immobilized metal ion affinity chromatography.  

PubMed

Methodologies to enrich heterogeneous types of phosphopeptides are critical for comprehensive mapping of the under-explored phosphoproteome. Taking advantage of the distinct binding affinities of Ga(3+) and Fe(3+) for phosphopeptides, we designed a metal-directed immobilized metal ion affinity chromatography for the sequential enrichment of phosphopeptides. In Raji B cells, the sequential Ga(3+)-Fe(3+)-immobilized metal affinity chromatography (IMAC) strategy displayed a 1.5-3.5-fold superior phosphoproteomic coverage compared to single IMAC (Fe(3+), Ti(4+), Ga(3+), and Al(3+)). In addition, up to 92% of the 6283 phosphopeptides were uniquely enriched in either the first Ga(3+)-IMAC (41%) or second Fe(3+)-IMAC (51%). The complementary properties of Ga(3+) and Fe(3+) were further demonstrated through the exclusive enrichment of almost all of 1214 multiply phosphorylated peptides (99.4%) in the Ga(3+)-IMAC, whereas only 10% of 5069 monophosphorylated phosphopeptides were commonly enriched in both fractions. The application of sequential Ga(3+)-Fe(3+)-IMAC to human lung cancer tissue allowed the identification of 2560 unique phosphopeptides with only 8% overlap. In addition to the above-mentioned mono- and multiply phosphorylated peptides, this fractionation ability was also demonstrated on the basic and acidic phosphopeptides: acidophilic phosphorylation sites were predominately enriched in the first Ga(3+)-IMAC (72%), while Pro-directed (85%) and basophilic (79%) phosphorylation sites were enriched in the second Fe(3+)-IMAC. This strategy provided complementary mapping of different kinase substrates in multiple cellular pathways related to cancer invasion and metastasis of lung cancer. Given the fractionation ability and ease of tip preparation of this Ga(3+)-Fe(3+)-IMAC, we propose that this strategy allows more comprehensive characterization of the phosphoproteome both in vitro and in vivo. PMID:24313913

Tsai, Chia-Feng; Hsu, Chuan-Chih; Hung, Jo-Nan; Wang, Yi-Ting; Choong, Wai-Kok; Zeng, Ming-Yao; Lin, Pei-Yi; Hong, Ruo-Wei; Sung, Ting-Yi; Chen, Yu-Ju

2014-01-01

378

Computational study of the complexation of metal ion precursors in dendritic polymers  

E-print Network

such as abinitio calculations and molecular dynamics (MD) simulations to investigate the complexation of Cu(II) and Pt(II) metal ions to a polyamidoamine (PAMAM) dendritic polymer from structural, thermodynamic, and kinetic viewpoints. First, we analyze the local...

Tarazona Vasquez, Francisco

2009-05-15

379

Significant thermal conductivity enhancement in graphene oxide papers modified with alkaline earth metal ions  

NASA Astrophysics Data System (ADS)

The thermal conductivities of graphene oxide paper (GOP) and the alkaline earth metal ions (Mg2+, Ca2+) modified analogues, prepared by a facile vacuum filtration method, were measured by a laser flash method. The thermal conductivities of GOP, Mg-modified GOP, and Ca-modified GOP are 3.91 W/(m × K), 32.05 W/(m × K), and 61.38 W/(m × K), respectively, which indicate the modification of GOP with metal ions has resulted in significant enhancement in thermal conduction properties compared with unmodified GOP. The crosslink between graphene oxide sheet and metal ions, the neat stacking of graphene oxide sheets in modified GOP, together with the intercalation of metal ions into the gallery spaces between the graphene oxide sheet basal planes, result in a decrease of thermal resistance of the boundary and an increase of contact surface, thus increases the thermal conductivity of modified graphene oxide paper.

Yu, Wei; Xie, Huaqing; Li, Fengxian; Zhao, Junchang; Zhang, Zhenhai

2013-09-01

380

Metal ion dependency of serine racemase from Dictyostelium discoideum.  

PubMed

D-Serine is known to act as an endogenous co-agonist of the N-methyl-D-aspartate receptor in the mammalian brain and is endogenously synthesized from L-serine by a pyridoxal 5'-phosphate-dependent enzyme, serine racemase. Though the soil-living mycetozoa Dictyostelium discoideum possesses no genes homologous to that of NMDA receptor, it contains genes encoding putative proteins relating to the D-serine metabolism, such as serine racemase, D-amino acid oxidase, and D-serine dehydratase. D. discoideum is an attractive target for the elucidation of the unknown functions of D-serine such as a role in cell development. As part of the elucidation of the role of D-serine in D. discoideum, we cloned, overexpressed, and examined the properties of the putative serine racemase exhibiting 46% amino acid sequence similarity with the human enzyme. The enzyme is unique in its stimulation by monovalent cations such as Na(+) in addition to Mg(2+) and Ca(2+), which are well-known activators for the mammalian serine racemase. Mg(2+) or Na(+) binding caused two- to ninefold enhancement of the rates of both racemization and dehydration. The half-maximal activation concentrations of Mg(2+) and Na(+) were determined to be 1.2 ?M and 2.2 mM, respectively. In the L-serine dehydrase reaction, Mg(2+) and Na(+) enhanced the k (cat) value without changing the K (m) value. Alanine mutation of the residues E207 and D213, which correspond to the Mg(2+)-binding site of Schizosaccharomyces pombe serine racemase, abolished the Mg(2+)- and Na(+)-dependent stimulation. These results suggest that Mg(2+) and Na(+) share the common metal ion-binding site. PMID:22311068

Ito, Tomokazu; Murase, Hirotaka; Maekawa, Motoki; Goto, Masaru; Hayashi, Shuhei; Saito, Hajime; Maki, Masatoshi; Hemmi, Hisashi; Yoshimura, Tohru

2012-10-01

381

Metal Ion Dependence of Recombinant Escherichia coli Allantoinase  

PubMed Central

Allantoinase is a suspected dinuclear metalloenzyme that catalyzes the hydrolytic cleavage of the five-member ring of allantoin (5-ureidohydantoin) to form allantoic acid. Recombinant Escherichia coli allantoinase purified from overproducing cultures amended with 2.5 mM zinc, 1 mM cobalt, or 1 mM nickel ions was found to possess ?1.4 Zn, 0.0 Co, 0.0 Ni, and 0.4 Fe; 0.1 Zn, 1.0 Co, 0.0 Ni, and 0.2 Fe; and 0.0 Zn, 0.0 Co, 0.6 Ni, and 0.1 Fe per subunit, respectively, whereas protein obtained from nonamended cultures contains near stoichiometric levels of iron. We conclude that allantoinase is incompletely activated in the recombinant cells, perhaps due to an insufficiency of a needed accessory protein. Enzyme isolated from nonsupplemented cultures possesses very low activity (kcat = 34.7 min?1) compared to the zinc-, cobalt-, and nickel-containing forms of allantoinase (kcat values of 5,000 and 28,200 min?1 and 200 min?1, respectively). These rates and corresponding Km values (17.0, 19.5, and 80 mM, respectively) are significantly greater than those that have been reported previously. Absorbance spectroscopy of the cobalt species reveals a band centered at 570 nm consistent with five-coordinate geometry. Dithiothreitol is a competitive inhibitor of the enzyme, with significant Ki differences for the zinc and cobalt species (237 and 795 ?M, respectively). Circular dichroism spectroscopy revealed that the zinc enzyme utilizes only the S isomer of allantoin, whereas the cobalt allantoinase prefers the S isomer, but also hydrolyzes the R isomer at about 1/10 the rate. This is the first report for metal content of allantoinase from any source. PMID:12486048

Mulrooney, Scott B.; Hausinger, Robert P.

2003-01-01

382

Electron transport studies in single transition metal ions doped borophosphate glasses  

Microsoft Academic Search

Three series of boro-phosphate glasses doped with single transition metal ions, Cuo, Fe2O3 and CoO have been prepared by melt quenching method and investigated for room temperature density and dc electrical conductivity in the temperature range from 325 to 600K. The density increased with increasing transition metal ions concentration in all the three series. The measured conductivities were in the

B. Vijaya kumar; T. Sankarappa; Santoshkumar; S. S. Veena

2009-01-01

383

Silica coated magnetite nanoparticles for removal of heavy metal ions from polluted waters  

E-print Network

Magnetic removal of Hg2+ and other heavy metal ions like Cd2+, Pb2+ etc. using silica coated magnetite particles from polluted waters is a current topic of active research to provide efficient water recycling and long term high quality water. The technique used to study the bonding characteristics of such kind of nanoparticles with the heavy metal ions is a very sensitive hyperfine specroscopy technique called the perturbed angular correlation technique (PAC).

Dash, Monika

2013-01-01

384

Effects of impregnated metal ions on air\\/CO 2-gasification of woody biomass  

Microsoft Academic Search

Several impregnated metal ions (Fe (III), Co (II), Ni (II), and Ru (IV)) and a raw iron ore (natural limonite) were examined as catalysts for gasification of pine sawdust in air\\/CO2 at 700 and 800°C. The yields of char and tar both increased with increasing CO2 content in the feed gas. All the impregnated metal ions, in particular Ni (II),

Scott Hurley; Hanning Li

2010-01-01

385

Adsorption of some bivalent heavy metal ions from aqueous solutions by manganese nodule leached residues  

Microsoft Academic Search

The leached residue, generated after selective extraction of Cu, Ni, and Co in sulfur dioxide-ammonia leaching of manganese nodules, was characterized and batch isothermal adsorption experiments were conducted at ambient temperature to evaluate the effectiveness of the water-washed leached residue for removal of different bivalent metal ions from aqueous synthetic solutions. The effects of pH, initial metal ion concentrations, amount

Nigamananda Das; Ranajit Kumar Jana

2006-01-01

386

Consistency and efficiency of standard swipe procedures taken on slightly radioactive contaminated metal surfaces.  

PubMed

In radiation work areas, a standard "swipe" procedure is widely used to evaluate the extent of contamination on surfaces. This report documents the variability in results of swipes carried out on various metal surfaces and the variability between different experienced health physics technicians. Also, there is an issue of the efficiency of the first swipe in terms of what fraction of the total absorbed surface contamination is detected by a swipe. The samples used for this study were metal surfaces uniformly exposed in the spent fuel pool of a nuclear power plant The primary surfaces studied were those usually found on spent fuel transportation casks (mainly 304 stainless steel in the U.S.), which are submerged in the spent fuel pools for loading or unloading of the highly radioactive fuel assemblies from nuclear power plants. These surfaces become contaminated with suspended and dissolved radionuclides, primarily 137Cs, 134Cs, and 60Co, in the spent fuel pool. A detailed evaluation was conducted of variations in the swipe measurements made on these metal samples using repeated swipes of the same area by the same technician and comparing swipes of one technician to those of another on similar surfaces. Rough surface finishes showed considerable inconsistency (approximately 30% variation) from one technician to another, but smooth surface finishes show substantially better consistency (<10% variation) between technicians. The "efficiencies" of a single swipe, particularly the initial swipe, expressed as a fraction of total "removable" contamination, ranged from approximately 10% to 20% for the stainless steel and titanium surfaces. Aluminum surfaces, on the other hand, showed much higher efficiencies on the initial swipe. However, in terms of the total contamination imbedded in the surfaces, the first swipe picked up only between 0.5% and 3% of the total adsorbed contamination. The overall results show the wide variations that routinely occur in swipe results on portions of surfaces that would be expected to give consistent results. These difference are an order of magnitude or more greater than the counting statistical errors. PMID:11316089

Jung, H; Kunze, J F; Nurrenbern, J D

2001-05-01

387

Pure ion current collection in ion sensitive probe measurement with a metal mesh guard electrode for evaluation of ion temperature in magnetized plasma  

SciTech Connect

This paper presents a new design of ion sensitive probe (ISP) that enables collection of pure ion current for accurate measurement of the perpendicular ion temperature in magnetized plasmas. The new type of ISP resolves a longstanding issue widely observed in ISP type measurements, namely, that the current-voltage characteristic is smeared by an unexpected electron current in the standard ISP model. The new ISP is equipped with a fine scale metal mesh on the sensor entrance to prevent electrons from flowing to the sensor, a phenomenon considered to be caused by the space-charge effect. The new ISP successfully measured the ion temperature of electron cyclotron resonance plasmas.

Hsieh, Tung-Yuan; Kawamori, Eiichirou [Institute of Space, Astrophysical and Plasma Sciences, National Cheng Kung University, Taiwan (China); Nishida, Yasushi [Plasma and Space Science Center, National Cheng Kung University, Taiwan (China)

2013-02-15

388

Biosorption of heavy metal ions from aqueous solution by red macroalgae.  

PubMed

Biosorption is an effective process for the removal and recovery of heavy metal ions from aqueous solutions. The biomass of marine algae has been reported to have high biosorption capacities for a number of heavy metal ions. In this study, four species of red seaweeds Corallina mediterranea, Galaxaura oblongata, Jania rubens and Pterocladia capillacea were examined to remove Co(II), Cd(II), Cr(III) and Pb(II) ions from aqueous solution. The experimental parameters that affect the biosorption process such as pH, contact time and biomass dosage were studied. The maximum biosorption capacity of metal ions was 105.2mg/g at biomass dosage 10 g/L, pH 5 and contact time 60 min. The biosorption efficiency of algal biomass for the removal of heavy metal ions from industrial wastewater was evaluated for two successive cycles. Galaxaura oblongata biomass was relatively more efficient to remove metal ions with mean biosorption efficiency of 84%. This study demonstrated that these seaweeds constitute a promising, efficient, cheap and biodegradable sorbent biomaterial for lowering the heavy metal pollution in the environment. PMID:21798665

Ibrahim, Wael M

2011-09-15

389

High-energy metal ion implantation for reduction of surface resistivity of alumina ceramic  

SciTech Connect

In this work, the possibility to increase the surface conductivity of ceramic insulators through their treatment with accelerated metal ion beams produced by a MevvaV.Ru vacuum arc source is demonstrated. The increase in surface conductivity is made possible due to experimental conditions in which an insulated collector is charged by beam ions to a potential many times lower than the accelerating voltage, and hence, than the average beam ion energy. The observed effect of charge neutralization of the accelerated ion beam is presumably associated with electrons knocked out of the electrodes of the accelerating system of the source and of the walls of the vacuum chamber by the accelerated ions.

Gushenets, V. I.; Nikolaev, A. G.; Oks, E. M.; Savkin, K. P.; Yushkov, G. Yu. [Institute of High Current Electronics SB RAS, Tomsk (Russian Federation); Brown, I. G. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

2012-02-15

390

DNAzyme crosslinked hydrogel: a new platform for visual detection of metal ions.  

PubMed

We propose the use of DNAzyme as a crosslinker of hydrogel to develop a catalytic platform for the sensing of metal ions. The DNAzyme crosslinked hydrogel can undergo gel-sol transition in response to Cu(2+) ions, which enables sensitive visual detection of Cu(2+) by observing the release of pre-trapped AuNPs. PMID:21629909

Lin, Haoxue; Zou, Yuan; Huang, Yishun; Chen, Jie; Zhang, Wei Yun; Zhuang, Zhixia; Jenkins, Gareth; Yang, Chaoyong James

2011-09-01

391

Water uptake and migration effects of electroactive ion-exchange polymer metal composite (IPMC) actuator  

Microsoft Academic Search

The low actuating voltage and quick bending responses of ion-exchange polymer metal composite (IPMC) are considered very attractive for the construction of various types of actuators and sensors. The principle of IPMC actuation under electric field has been believed to be the ion cluster flux and electro-osmotic drag of water from the anode to cathode direction through the hydrophilic channels

Jun Ho Lee; Jong Hoon Lee; Jae-Do Nam; Hyoukryeol Choi; Kwangmok Jung; Jae Wook Jeon; Young Kwan Lee; Kwang Jin Kim; Yongsug Tak

2005-01-01

392

Property enchancement of polyimide films by way of the incorporation of lanthanide metal ions  

NASA Technical Reports Server (NTRS)

Lanthanide metal ions were incorporated into the polyimide derived from 2,2-bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) and 1,3-bis(aminophenoxy) benzene (APB) in an attempt to produce molecular level metal-polymer composites. The lanthanide series of metal ions (including aluminum, scandium, and yttrium) provide discrete and stable metal ions in the 3+ oxidation state. Throughout the series there is a uniform variation in ionic size ranging from 50 pm for aluminum to a maximum of 103.4 pm for cerium and gradually decreasing again to 84.8 pm for lutetium. The high charge-to-size ratio for these ions as well as the ability to obtain large coordination numbers makes them excellent candidates for interacting with the polymer substructure. The distinct lack of solubility of simple lanthanide salts such as the acetates and halides has made it difficult to obtain metal ions distributed in the polymer framework as discrete ions or metal complexes rather than microcomposites of metal clusters. (Lanthanum nitrates are quite soluble, but the presence of the strongly oxidizing nitrate ion leads to serious degradation of the polymer upon thermal curing. This work was successful at extending the range of soluble metals salts by using chelating agents derived from the beta-diketones dipivaloylmethane, dibenzoylmethane, trifluoroacetylacetone, and hexafluoroacetylacetone. Metal acetates which are insoluble in dimethylacetamide dissolve readily in the presence of the diketones. Addition of the polyimide yields a homogeneous resin which is then cast into a clear film. Upon curing clear films were obtained with the dibenzoylmethane and trifluoroacetylacetone ligands. The dipavaloylmethane precipitates the metal during the film casting process, and hexafluoroacetylacetone gives cured films which are deformed and brittle. These clear films are being evaluated for the effect of the metal ions on the coefficient of thermal expansion, resistance to atomic oxygen, and on selective gas permeability. Much more commonly than above, polyimide films are prepared by casting the film as the poly(amic acid) precursor which is then converted to the imidized form during the thermal cure cycle. Very limited success was achieved in the past in adding lanthanide metal ions to the amide precursors because of gellation and lack of solubility. With the use of the diketone ligands cited above, the solubility and gellation problems were overcome. However, the films after curing were clear but unacceptably brittle. Attempts to overcome this cure embrittlement problem are in progress.

Thompson, David W.

1993-01-01

393

A cheap and compact mass spectrometer for radioactive ions based on a Wien filter  

Microsoft Academic Search

This paper presents simulations of a mass spectrometer composed of one or two Wien filters. The ion source used is MONO1000 ECRIS. This ion source can produce singly charged ions with high efficiency, especially for gaseous materials. After extraction, the ions are mass selected and can be injected either into a beam line towards an experiment area or in an

C. Pierret; L. Maunoury; J. Y. Pacquet; M.-G. Saint-Laurent; O. Tuske

2008-01-01

394

Rare-earth neutral metal injection into an electron beam ion trap plasmaa)  

NASA Astrophysics Data System (ADS)

We have designed and implemented a neutral metal vapor injector on the SuperEBIT high-energy electron beam ion trap at the Lawrence Livermore National Laboratory. A horizontally directed vapor of a europium metal is created using a thermal evaporation technique. The metal vapor is then spatially collimated prior to injection into the trap. The source's form and quantity constraints are significantly reduced making plasmas out of metal with vapor pressures ?10-7 Torr at ?1000 °C more obtainable. A long pulsed or constant feed metal vapor injection method adds new flexibility by varying the timing of injection and rate of material being introduced into the trap.

Magee, E. W.; Beiersdorfer, P.; Brown, G. V.; Hell, N.

2014-11-01

395

Poultry litter-based activated carbon for removing heavy metal ions in water.  

PubMed

Utilization of poultry litter as a precursor material to manufacture activated carbon for treating heavy metal-contaminated water is a value-added strategy for recycling the organic waste. Batch adsorption experiments were conducted to investigate kinetics, isotherms, and capacity of poultry litter-based activated carbon for removing heavy metal ions in water. It was revealed that poultry litter-based activated carbon possessed significantly higher adsorption affinity and capacity for heavy metals than commercial activated carbons derived from bituminous coal and coconut shell. Adsorption of metal ions onto poultry litter-based carbon was rapid and followed Sigmoidal Chapman patterns as a function of contact time. Adsorption isotherms could be described by different models such as Langmuir and Freundlich equations, depending on the metal species and the coexistence of other metal ions. Potentially 404 mmol of Cu2+, 945 mmol of Pb2+, 236 mmol of Zn2+, and 250-300 mmol of Cd2+ would be adsorbed per kg of poultry litter-derived activated carbon. Releases of nutrients and metal ions from litter-derived carbon did not pose secondary water contamination risks. The study suggests that poultry litter can be utilized as a precursor material for economically manufacturing granular activated carbon that is to be used in wastewater treatment for removing heavy metals. PMID:19783133

Guo, Mingxin; Qiu, Guannan; Song, Weiping

2010-02-01

396

Coloring a Superabsorbent Polymer with Metal Ions: An Undergraduate Chemistry Experiment  

ERIC Educational Resources Information Center

A novel undergraduate chemistry experiment involving superabsorbent polymers commonly used in diapers and other personal care products is described. Students observe the removal of divalent transition-metal ions from aqueous solutions by the polymers. With the procedures provided, students are able to color the superabsorbent polymers with metal…

Yaung, Jing-Fun; Chen, Yueh-Huey

2009-01-01

397

A self-sensing ion conducting polymer metal composite (IPMC) actuator  

Microsoft Academic Search

This paper describes a novel self-sensing ion-conductive polymer metal composite (IPMC) actuator. The actuator gives feedback of its own position and thereby can also be used as a position sensor. Unlike the IPMC sensors reported so far, the working principle of this actuator is based on the observation that the resistance of the IPMC metal surface electrode is correlated to

Andres Punning; Maarja Kruusmaa; Alvo Aabloo

2007-01-01

398

Recovery of metal ions from spent solutions used to electrodeposit magnetic materials  

Microsoft Academic Search

The feasibility of using electrodialysis to extract metal ions such as cobalt and nickel from spent electroplating baths employing citrate salts was examined. Modeling of metal-citrate speciation in electrolytes was initially used to identify conditions under which such a separation process might be possible. The most promising separation scheme identified in these studies required acidification of the electrolyte to de-complex

T. A. Green; S. Roy; K. Scott

2001-01-01

399

Reductive sorption of molecular oxygen from water by nanodisperse metals in an ion-exchanger matrix  

NASA Astrophysics Data System (ADS)

It is shown that the reduction of oxygen dissolved in water by metal (Ag, Cu, Bi, and Ni) — KU-23 ion exchanger nanocomposite can be inhibited by either internal diffusion or kinetic mechanisms, depending on the nature of the metal and its particle size.

Polyanskii, L. N.; Khorol'Skaya, S. V.; Kravchenko, T. A.; Peshkov, S. V.; Kipriyanova, E. S.; Starodubova, S. P.

2012-04-01

400

SUMMARY REPORT: CONTROL AND TREATMENT TECHNOLOGY FOR THE METAL FINISHING INDUSTRY: ION EXCHANGE  

EPA Science Inventory

This Technology Transfer ummary Report is one of a series of reports that summarizes a pollution control technology for the metal finishing industry. he 45-page report is intended to promote an understanding of the use of ion exchange in the metal finishing industry. The sections...

401

Integrated FIA\\/HPLC method for preconcentration and determination of transition metal ions  

Microsoft Academic Search

Summary  An automatic method based on the combination of a flow injection (FI) manifold with a liquid chromatograph has been developed for the enrichment and determination of transition metal ions in water samples. Alternatively, the FI configuration can be used as a screening system for the determination of the total concentration of heavy metals. Two-parameter expressions for calibration graphs involving preconcentration

P. Richter; J. M. Fernández-Romero; M. D. Luque de Castro; M. Valcárcel

1992-01-01

402

Bioleaching of metals from spent lithium ion secondary batteries using Acidithiobacillus ferrooxidans  

Microsoft Academic Search

Bioleaching of spent lithium ion secondary batteries, containing LiCoO2, was attempted in this investigation. The present study was carried out using chemolithotrophic and acidophilic bacteria Acidithiobacillus ferrooxidans, which utilized elemental sulfur and ferrous ion as the energy source to produce metabolites like sulfuric acids and ferric ion in the leaching medium. These metabolites helped dissolve metals from spent batteries. Bio-dissolution

Debaraj Mishra; Dong-Jin Kim; D. E. Ralph; Jong-Gwan Ahn; Young-Ha Rhee

2008-01-01

403

The study of a fundamental law in extracting metal ions from a rf ion source by applying a plasma chemical reaction  

NASA Astrophysics Data System (ADS)

Experimental metal ions are extracted from a rf ion source by applying a plasma chemical reaction. The process has been generalized into a law; it is used in practicing and many metal ions are extracted, such as: Re+, W+, Mo+, Ta+, Pt+, Pd+, Au+, Ag+, Nb+, Ti+, V+, Cr+, Ni+, Fe+, Cu+, Zn+, Ga+, Ge+, Se+, Si+, Al+, Mg+, Be+, Li+, Bi+, In+, Sn+, Pb+, Cd+, etc., and rare-earth ions Y+, Nd+, Ce+, Sm+, Tm+, Dy+, Gd+, Er+, and so on.

Guibin, Bai; Xiuling, Shi; Zhaoxing, Meng

1992-04-01

404

18-Electron rule inspired Zintl-like ions composed of all transition metals.  

PubMed

Zintl phase compounds constitute a unique class of compounds composed of metal cations and covalently bonded multiply charged cluster anions. Potential applications of these materials in solution chemistry and thermoelectric materials have given rise to renewed interest in the search for new Zintl ions. Up to now these ions have been mostly composed of group 13, 14, and 15 post-transition metal elements and no Zintl ions composed of all transition metal elements are known. Using gradient corrected density functional theory we show that the 18-electron rule can be applied to design a new class of Zintl-like ions composed of all transition metal atoms. We demonstrate this possibility by using Ti@Au12(2-) and Ni@Au6(2-) di-anions as examples of Zintl-like ions. Predictive capability of our approach is demonstrated by showing that FeH6(4-) in an already synthesized complex metal hydride, Mg2FeH6, is a Zintl-like ion, satisfying the 18-electron rule. We also show that novel Zintl phase compounds can be formed by using all transition metal Zintl-like ions as building blocks. For example, a two-dimensional periodic structure of Na2[Ti@Au12] is semiconducting and nonmagnetic while a one-dimensional periodic structure of Mg[Ti@Au12] is metallic and ferromagnetic. Our results open the door to the design and synthesis of a new class of Zintl-like ions and compounds with potential for applications. PMID:25139391

Zhou, Jian; Giri, Santanab; Jena, Purusottam

2014-10-01

405

Submicro and Nano Structured Porous Materials for the Production of High-Intensity Exotic Radioactive Ion Beams  

E-print Network

ISOLDE, the CERN Isotope Separator On-line DEvice is a unique source of low energy beams of radioactive isotopes - atomic nuclei that have too many or too few neutrons to be stable. The facility is like a small ‘chemical factory’, giving the possibility of changing one element to another, by selecting the atomic mass of the required isotope beam in the mass separator, rather as the ‘alchemists’ once imagined. It produces a total of more than 1000 different isotopes from helium to radium, with half-lives down to milliseconds, by impinging a 1.4 GeV proton beam from the Proton Synchrotron Booster (PSB) onto special targets, yielding a wide variety of atomic fragments. Different components then extract the nuclei and separate them according to mass. The post-accelerator REX (Radioactive beam EXperiment) at ISOLDE accelerates the radioactive beams up to 3 MeV/u for many experiments. A wide international user radioactive ion beam (RIB) community investigates fundamental aspects of nuclear physics, particle...

Fernandes, Sandrina; Stora, Thierry

2010-01-01

406

Selective adsorption of metal ions by chemically-modified MCM-41  

NASA Astrophysics Data System (ADS)

Selective adsorbents were developed for removal and recovery of heavy metals from aqueous medium. As heavy metals interact with surface moieties differently depending on their chemical properties, tailor-made adsorbents were synthesized for metal separation from aqueous solution based on different adsorption mechanisms. This is the first comprehensive study in the design of adsorbent for selective adsorption of metal ions based on a nanostructured material, MCM-41. Adsorption mechanism studies by FTIR and XPS found that hard-soft acid-base principle, surface complexation and ion-exchange were the main interactions between metal ions and surface functional groups. The adsorption selectivity of SH-MCM-41 obeys the hard-soft acid-base principle. It was suitable for separation of hard and soft metal ions such as Ag+ and Cu 2+. Stability constants could be as the guideline for predicting the adsorption of NH2-MCM-41 which was able to separate metals with different complexing ability. Furthermore, ion-exchange mechanism governs the adsorption of COONa-MCM-41 and it was capable of separating cationic metals from metallic oxyanions. Factors such as functional group loading, amount of adsorbent, solution pH and metal composition of solution could affect both adsorption capacity and selectivity of the adsorbents depending on the adsorption mechanisms. By identifying the adsorption mechanism, the selective adsorbents was designed for precious metal recovery and toxic metal separation. It was found that both SH-MCM-41 and NH2-MCM-41 were able to remove gold in the presence of other metals and these adsorbents were efficient to adsorb trace amount of gold from the solution. The regenerable NH2-MCM-41 could be re-used for five times without loss of performance. On the other hand, NH2-MCM-41 was used to separate toxic cadmium ions from Ni-Cd solution. It was found that the addition of EDTA improved the adsorption selectivity. NH2-MCM-41 only remove Cd2+ at pH5.0 while the adsorbent removed Ni2+ at pH3.0. This introduces an opportunity to recover both metal ions from spent Ni-Cd battery wastes.

Lam, Koon Fung

407

EXAFS study on metal cluster doped silica glass obtained by ion implantation procedures  

Microsoft Academic Search

Metal-doped glasses were prepared by double ion implantation (Ag+Cu and Au+Cu) in silica glass. X-ray absorption spectroscopy was used to study the different oxidation states of the dopant metals and the possible formation of metal or alloy clusters. We present an investigation on co-implanted silica glass at the Cu K, Ag K and Au LIII edges. The local atomic order

G. Battaglin; E. Cattaruzza; F D'Acapito; F. Gonella; P. Mazzoldi; S. Mobilio; F. Priolo

1998-01-01

408

Generation of reactive oxygen species by interaction between antioxidants used as food additive and metal ions.  

PubMed

Food additives, such as preservatives, sweeteners, coloring agents, and flavoring agents, are widely used in food manufacturing. However, their combined effects on the human body are not known. The purpose of this study was to examine whether combinations of antioxidants and metal ions generate reactive oxygen species (ROS) under in vitro conditions using electron spin resonance (ESR). Among the metal ions examined, only iron and copper generated ROS in the presence of antioxidants. Moreover, certain phenolic antioxidants having pro-oxidant activity induced DNA oxidation and degradation via the generation of high levels of ROS in the presence of copper ion, resulting in complete degradation of DNA in vitro. PMID:25212818

Iwasaki, Yusuke; Oda, Momoko; Tsukuda, Yuri; Nagamori, Yuki; Nakazawa, Hiroyuki; Ito, Rie; Saito, Koichi

2014-01-01

409

Development of metallic ion beams at the Institute of Modern Physics  

NASA Astrophysics Data System (ADS)

Many experiments have been made to produce metallic ion beams since 1998 at IMP (Institute of Modern Physics). We have designed a small oven that can reach a temperature of more than 1300 °C using 110 W electric power. Typical ion beam currents of 70 e?A of Ca12+, 60 e?A of Mg8+, 25 e?A of Pb27+ have been provided to the IMP cyclotron operation by the LECR2 (LanZhou ECR No. 2). We have also obtained some good results by the metallic ions from volatile compounds method on LECR3 (LanZhou ECR No. 3).

Cao, Y.; Zhang, Z. M.; Ma, L.; Sun, L. T.; Zhao, H. W.

2004-05-01

410

Adherence of ion beam sputter deposited metal films on H-13 steel  

NASA Technical Reports Server (NTRS)

An electron bombardment argon ion source was used to sputter deposit 17 different metal and metal oxide films ranging in thickness from 1 to 8 micrometers on H-13 steel substrates. The film adherence to the substrate surface was measured using a tensile test apparatus. Comparisons in bond strength were made between ion beam, ion plating, and RF deposited films. A protective coating to prevent heat checking in H-13 steel dies used for aluminum die casting was studied. The results of exposing the coated substrates to temperatures up to 700 degrees are presented.

Mirtich, M. J.

1980-01-01

411

Adsorption of heavy metal ions onto dithizone-anchored poly (EGDMA-HEMA) microbeads  

Microsoft Academic Search

The dithizone-anchored poly (EGDMA-HEMA) microbeads were prepared for the removal of heavy metal ions (i.e. cadmium, mercury, chromium and lead) from aqueous media containing different amounts of these ions (25–500 ppm) and at different pH values (2.0–8.0). The maximum adsorptions of heavy metal ions onto the dithizone-anchored microbeads from their solutions was 18.3, Cd(II); 43.1, Hg(II); 62.2, Cr(III) and 155.2

B Salih; A Denizli; C Kavakl?; R Say; E Pi?kin

1998-01-01

412

Covalent bonding and magnetic properties of transition metal ions  

Microsoft Academic Search

This review is mainly concerned with octahedrally co-ordinated ions with an unfilled d shell. The wave functions of the magnetic electrons are considered first, the covalency being taken into account by admixing ligand s and p orbits into the central ion d orbits. The origin of these admixtures is discussed in a simple way, and a short survey is given

J. Owen; J. H. M. Thornley

1966-01-01

413

Effects of lability of metal complex on free ion measurement using DMT.  

PubMed

Very low concentrations of free metal ion in natural samples can be measured using the Donnan membrane technique (DMT) based on ion transport kinetics. In this paper, the possible effects of slow dissociation of metal complexes on the interpretation of kinetic DMT are investigated both theoretically and experimentally. The expressions of the lability parameter, Lgrangian , were derived for DMT. Analysis of new experimental studies using synthetic solution containing NTA as the ligand and Cu(2+) ions shows that when the ionic strength is low (metals. By comparing the fraction of labile species measured using other dynamic sensors (DGT, GIME) in several freshwaters, it is concluded that in most waters ion transport in DMT is controlled by diffusion in the membrane. Only in very soft waters (<0.7 mM Ca+Mg), the dissociation rate of natural metal complex may influence ion transport in DMT. In this case, neglecting this effect may lead to an underestimation of the free metal ion concentration measured. PMID:20163175

Weng, Liping; Van Riemsdijk, Willem H; Temminghoff, Erwin J M

2010-04-01

414

Effects of transition metal ion identity and ?-cation interactions in metal-bis(peptide) complexes containing phenylalanine.  

PubMed

Electrospray ionization-tandem mass spectrometry was used to study the effects of the metal ion identity and ?-cation interactions on the dissociation pathways of metal-bis(peptide) complexes, where the metal is either Mn(2+), Co(2+), Ni(2+), Cu(2+), or Zn(2+); and the peptide is either FGGF, GGGG, GF, or GG, where G is glycine and F is phenylalanine. The [(FGGF)(FGGF-H) + M(2+)](+) and [(GGGG)(GGGG-H) + M(2+)](+) complexes dissociated by losing one FGGF or GGGG, respectively. Relative binding affinities were measured using the crossover points, where the parent and product ions were equal in ion abundance and a normalized-collision energy scale. The results indicate the relative binding affinities for FGGF and GGGG follow the same order with respect to the transition metal ion identity: Cu(2+) < Ni(2+) < Mn(2+) ? Zn(2+) < Co(2+), and the ?-cation interactions in the FGGF complex have a measureable stabilizing effect. In contrast, the main fragmentation channels of [(GF)(GF-H) + M(2+)]+ and [(GG)(GG-H) + M(2+)](+) are loss of CO(2) and 2CO(2) with the [(GF)(GF-H) + M(2+)](+) complex also exhibiting cinnamic acid ,GF, residual glycine, cinnamate and styrene loss. PMID:21173465

Utley, Brandon; Angel, Laurence A

2010-01-01

415

Structure simulation into a lamellar supramolecular network and calculation of the metal ions/ligands ratio  

PubMed Central

Background Research interest in phosphonates metal organic frameworks (MOF) has increased extremely in the last two decades, because of theirs fascinating and complex topology and structural flexibility. In this paper we present a mathematical model for ligand/metal ion ratio of an octahedral (Oh) network of cobalt vinylphosphonate (Co(vP)·H2O). Results A recurrent relationship of the ratio between the number of ligands and the number of metal ions in a lamellar octahedral (Oh) network Co(vP)·H2O, has been deducted by building the 3D network step by step using HyperChem 7.52 package. The mathematical relationship has been validated using X ray analysis, experimental thermogravimetric and elemental analysis data. Conclusions Based on deducted recurrence relationship, we can conclude prior to perform X ray analysis, that in the case of a thermogravimetric analysis pointing a ratio between the number of metal ions and ligands number around 1, the 3D network will have a central metal ion that corresponds to a single ligand. This relation is valid for every type of supramolecular network with divalent metal central ion Oh coordinated and bring valuable information with low effort and cost. PMID:22932493

2012-01-01

416

Transmittance properties and TEM observation of metal doped glass by field-assisted ion exchange  

NASA Astrophysics Data System (ADS)

Metal (silver or copper) ions were doped into borosilicate glass using an electric field- assisted ion exchange method. The optical transmittance of the metal doped glass was measured to determine why the doped glass exhibited an excellent laser micro-machinability. The doped metal ions were found to have enhanced the optical absorption of the glass, especially in the ultraviolet range. This in turn facilitated the efficient absorption of incident laser irradiation, and hence improved laser machinability of the glass. The metal doped glass also exhibited some absorption in the visible range, leading to a slight yellow-brown coloration. Transmission electron microscope (TEM) observations indicated that the metal ions had penetrated the glass and therein formed nanometer-sized (~6 nm) fine particles. In an attempt to control the optical characteristics in the ultraviolet-visible range, metal doped glass was heat-treated following the ion exchange doping step. In the case of silver-doped glass with heat treatment at 723 K, silver nanoparticles aggregated locally yielding an inhomogeneous structure. The heat-treated samples had a high optical absorption in the ultraviolet range.

Matsusaka, Souta; Nomura, Taketsugu; Hidai, Hirofumi; Chiba, Akira; Morita, Noboru

2014-08-01

417

Surface enhanced Raman spectroscopy as a new spectral technique for quantitative detection of metal ions  

NASA Astrophysics Data System (ADS)

Four newly synthesized poly (propylene amine) dendrimers from first and second generation modified with 1,8-naphthalimide units in the dendrimer periphery have been investigated as ligands for the detection of heavy metal ions (Al3+, Sb2+, As2+, Cd2+ and Pb2+) by surface-enhanced Raman spectroscopy. Calibration curves were established for all metal ions between the concentration ranges of  1 x 10-6 to 5 x 10-4 M. It has been shown that these dendrimers can be coordinated, especially with different metal ions. Using dendrimer molecules and silver colloids at the same time allowed us to obtain an SERS signal from the abovementioned metal ions at very low concentrations. Principle component analysis (PCA) analysis was also applied to the collected SERS data. Four differentPCA models were developed to accomplish the discrimination of five metal ions, which interacted with each of the four dendrimer molecules, separately. A detailed investigation was performed in the present study to provide the basis of a new approach for heavy metal detection.

Temiz, Havva Tumay; Boyaci, Ismail Hakki; Grabchev, Ivo; Tamer, Ugur

2013-12-01

418

Surface enhanced Raman spectroscopy as a new spectral technique for quantitative detection of metal ions.  

PubMed

Four newly synthesized poly (propylene amine) dendrimers from first and second generation modified with 1,8-naphthalimide units in the dendrimer periphery have been investigated as ligands for the detection of heavy metal ions (Al(3+), Sb(2+), As(2+), Cd(2+) and Pb(2+)) by surface-enhanced Raman spectroscopy. Calibration curves were established for all metal ions between the concentration ranges of 1 x 10(-6) to 5 x 10(-4) M. It has been shown that these dendrimers can be coordinated, especially with different metal ions. Using dendrimer molecules and silver colloids at the same time allowed us to obtain an SERS signal from the abovementioned metal ions at very low concentrations. Principle component analysis (PCA) analysis was also applied to the collected SERS data. Four different PCA models were developed to accomplish the discrimination of five metal ions, which interacted with each of the four dendrimer molecules, separately. A detailed investigation was performed in the present study to provide the basis of a new approach for heavy metal detection. PMID:23973576

Temiz, Havva Tumay; Boyaci, Ismail Hakki; Grabchev, Ivo; Tamer, Ugur

2013-12-01

419

Ultrahigh-current-density metal-ion implantation and diamondlike-hydrocarbon films for tribological applications  

NASA Astrophysics Data System (ADS)

The metal-ion-implantation system used to implant metals into substrates are described. The metal vapor required for operation is supplied by drawing sufficient electron current from the plasma discharge to an anode-potential crucible so a solid, pure metal placed in the crucible will be heated to the point of vaporization. The ion-producing, plasma discharge is initiated within a graphite-ion-source body, which operates at high temperature, by using an argon flow that is turned off once the metal vapor is present. Extraction of ion beams several cm in diameter at current densities ranging to several hundred micro-A/sq cm on a target 50 cm downstream of the ion source were demonstrated using Mg, Ag, Cr, Cu, Si, Ti, V, B, and Zr. These metals were implanted into over 100 substrates (discs, pins, flats, wires). A model describing thermal stresses induced in materials (e.g. ceramic plates) during high-current-density implantation is presented. Tribological and microstructural characteristics of iron and 304-stainless-steel samples implanted with Ti or B are examined. Diamondlike-hydrocarbon coatings were applied to steel surfaces and found to exhibit good tribological performance.

Wilbur, P. J.

1993-09-01

420

Gettering of transition metals by cavities in silicon formed by helium ion implantation  

SciTech Connect

We have recently completed studies which quantitatively characterize the ability of nanometer-size cavities formed by He ion implantation to getter detrimental metal impurities in Si. Cavity microstructures formed in Si by ion implantation of He and subsequent annealing have been found to capture metal impurities by two mechanisms: (1) chemisorption on internal walls at low concentrations and (2) silicide precipitation at concentrations exceeding the solid solubility. Experiments utilizing ion-beam analysis, cross-sectional transmission electron microscopy, and secondary ion mass spectrometry were performed to quantitatively characterize the gettering effects and to determine the free energies associated with the chemisorbed metal atoms as a function of temperature. Mathematical models utilizing these results have been developed to predict gettering behavior.

Petersen, G.A.; Myers, S.M.; Follstaedt, D.M.

1996-09-01

421

Metal -Ion Chemistry In Clusters Initiated By Ionization/Dissociation Of Organometallic Precursors  

NASA Astrophysics Data System (ADS)

A novel method is described for the initiation and observation of transition metal neutral- and ion-molecule reactions in clusters. A heterocluster composed of organometallic molecules and reactant species is formed by coexpansion in a supersonic jet. Photoionization of the precursor molecules by a picosecond, 266 nm laser pulse efficiently strips away the ligands, leaving metal ions and metal cluster ions (and neutrals) in close proximity to reactant molecules. Subsequent reactions take place which are followed by monitoring the products by time-of-flight mass spectrometry. Both neutral and ion-molecule mechanisms are considered. Using iron pentacarbonyl as an example, the formation of metal ions and cluster ions is demonstrated and their reaction with nitric oxide, nitrous oxide, CS^2, CH_3I, and benzene is described. Comparisons will be drawn between the cluster and condensed phase chemistry. In addition, an interesting aspect of the photoionization/dissociation of [Fe(CO)_5]_mArn clusters will be presented whereby the strong Fe-CO bonds break while leaving the considerably weaker Fe-Ar bonds intact. Spectra showing the FeAr_n^+ and Fe_2Ar_n^+ cluster ions will be discussed and compared to