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Sample records for precious metals institute

  1. 41 CFR 109-45.1004 - Recovery and use of precious metals through the DOD Precious Metals Recovery Program.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... precious metals through the DOD Precious Metals Recovery Program. 109-45.1004 Section 109-45.1004 Public... PERSONAL PROPERTY 45.10-Recovery of Precious Metals § 109-45.1004 Recovery and use of precious metals through the DOD Precious Metals Recovery Program. DOE operates its own precious metals pool and...

  2. 41 CFR 109-45.1004 - Recovery and use of precious metals through the DOD Precious Metals Recovery Program.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... precious metals through the DOD Precious Metals Recovery Program. 109-45.1004 Section 109-45.1004 Public... PERSONAL PROPERTY 45.10-Recovery of Precious Metals § 109-45.1004 Recovery and use of precious metals through the DOD Precious Metals Recovery Program. DOE operates its own precious metals pool and...

  3. 41 CFR 109-45.1004 - Recovery and use of precious metals through the DOD Precious Metals Recovery Program.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... precious metals through the DOD Precious Metals Recovery Program. 109-45.1004 Section 109-45.1004 Public... PERSONAL PROPERTY 45.10-Recovery of Precious Metals § 109-45.1004 Recovery and use of precious metals through the DOD Precious Metals Recovery Program. DOE operates its own precious metals pool and...

  4. 41 CFR 109-45.1004 - Recovery and use of precious metals through the DOD Precious Metals Recovery Program.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... precious metals through the DOD Precious Metals Recovery Program. 109-45.1004 Section 109-45.1004 Public... PERSONAL PROPERTY 45.10-Recovery of Precious Metals § 109-45.1004 Recovery and use of precious metals through the DOD Precious Metals Recovery Program. DOE operates its own precious metals pool and...

  5. 41 CFR 109-45.1004 - Recovery and use of precious metals through the DOD Precious Metals Recovery Program.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... precious metals through the DOD Precious Metals Recovery Program. 109-45.1004 Section 109-45.1004 Public... PERSONAL PROPERTY 45.10-Recovery of Precious Metals § 109-45.1004 Recovery and use of precious metals through the DOD Precious Metals Recovery Program. DOE operates its own precious metals pool and...

  6. 48 CFR 945.607-2 - Recovering precious metals.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 5 2012-10-01 2012-10-01 false Recovering precious metals... Recovering precious metals. (b) Contractors generating contractor inventory containing precious metals shall... the DOE precious metals pool. This includes all precious metals in any form, including shapes,...

  7. 48 CFR 945.607-2 - Recovering precious metals.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Recovering precious metals... Recovering precious metals. (b) Contractors generating contractor inventory containing precious metals shall... the DOE precious metals pool. This includes all precious metals in any form, including shapes,...

  8. 48 CFR 208.7304 - Refined precious metals.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 3 2012-10-01 2012-10-01 false Refined precious metals... Government-Owned Precious Metals 208.7304 Refined precious metals. See PGI 208.7304 for a list of refined precious metals managed by DSCP....

  9. 48 CFR 208.7304 - Refined precious metals.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 3 2014-10-01 2014-10-01 false Refined precious metals... Government-Owned Precious Metals 208.7304 Refined precious metals. See PGI 208.7304 for a list of refined precious metals managed by DSCP....

  10. 48 CFR 208.7304 - Refined precious metals.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 3 2013-10-01 2013-10-01 false Refined precious metals... Government-Owned Precious Metals 208.7304 Refined precious metals. See PGI 208.7304 for a list of refined precious metals managed by DSCP....

  11. 48 CFR 208.7304 - Refined precious metals.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 3 2011-10-01 2011-10-01 false Refined precious metals... Government-Owned Precious Metals 208.7304 Refined precious metals. See PGI 208.7304 for a list of refined precious metals managed by DSCP....

  12. 48 CFR 245.607-2 - Recovering precious metals.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Recovering precious metals... Disposal of Contractor Inventory 245.607-2 Recovering precious metals. (b) Precious metals are silver, gold... office with disposition instructions for certain categories of precious metals-bearing...

  13. 48 CFR 208.7304 - Refined precious metals.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Refined precious metals... Government-Owned Precious Metals 208.7304 Refined precious metals. See PGI 208.7304 for a list of refined precious metals managed by DSCP....

  14. Recycling lead to recover refractory precious metals

    NASA Astrophysics Data System (ADS)

    Parga, J. R.; Muzquiz, G. G.; Valenzuela, J. L.; Ojebuoboh, F. K.

    2001-12-01

    Lead recycling has many benefits. For example, it provides an alternative to virgin lead, thereby avoiding the environmental impacts of primary lead smelting. In addition, as with other secondary metal operations, it consumes less energy at a lower cost than primary production. An emerging process has been evaluated in which these attributes are leveraged to process refractory precious metals ores. Direct cyanidation of refractory gold and silver ore yields poor gold and silver recoveries. In fact, some ores are simply not amenable to direct cyanidation. The process described in this paper consists of smelting lead-bearing material together with argentopyrite concentrate that contains precious metals. Sodium carbonate is used as a fluxing agent and scrap iron is used as a reductant. The reaction product is molten lead bullion enriched with the precious metals. Smelting recoveries of both silver and gold can be as high as 98%.

  15. Abundant Metals Give Precious Hydrogenation Performance

    SciTech Connect

    Bullock, R. Morris

    2013-11-29

    Homogeneous catalysts based on precious (noble) metals have had a profound influence on modern synthetic methods, enabling highly selective synthesis of organic compounds but typically require precious metal catalysts (Ru, Rh, Ir, Pt, and Pd). Increasing efforts have been devoted to the design and discovery of homogeneous catalysts using base metals (e.g., Mn, Fe, Co, Ni, Cu, Mo). Morris et al. report Fe catalysts for asymmetric hydrogenation of C=O bonds. Cobalt catalysts for asymmetric hydrogenation of C=C bonds are described by Chirik et al., and Beller et al. report new nanoscale iron catalysts for synthesis of functionalized anilines through hydrogenation of nitroarenes. The author’s work in this area is supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences. Pacific Northwest National Laboratory is operated by Battelle for the U.S. Department of Energy.

  16. 41 CFR 109-1.5108-4 - Precious metals.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 41 Public Contracts and Property Management 3 2012-01-01 2012-01-01 false Precious metals. 109-1....51-Personal Property Management Standards and Practices § 109-1.5108-4 Precious metals. Perpetual inventory records are to be maintained for precious metals....

  17. 41 CFR 109-27.5106 - Precious metals pool.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 41 Public Contracts and Property Management 3 2012-01-01 2012-01-01 false Precious metals pool. 109-27.5106 Section 109-27.5106 Public Contracts and Property Management Federal Property Management...-INVENTORY MANAGEMENT 27.51-Management of Precious Metals § 109-27.5106 Precious metals pool....

  18. 41 CFR 109-27.5106 - Precious metals pool.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 41 Public Contracts and Property Management 3 2014-01-01 2014-01-01 false Precious metals pool. 109-27.5106 Section 109-27.5106 Public Contracts and Property Management Federal Property Management...-INVENTORY MANAGEMENT 27.51-Management of Precious Metals § 109-27.5106 Precious metals pool....

  19. 41 CFR 109-1.5108-4 - Precious metals.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 41 Public Contracts and Property Management 3 2013-07-01 2013-07-01 false Precious metals. 109-1....51-Personal Property Management Standards and Practices § 109-1.5108-4 Precious metals. Perpetual inventory records are to be maintained for precious metals....

  20. 41 CFR 109-27.5106 - Precious metals pool.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 41 Public Contracts and Property Management 3 2011-01-01 2011-01-01 false Precious metals pool. 109-27.5106 Section 109-27.5106 Public Contracts and Property Management Federal Property Management...-INVENTORY MANAGEMENT 27.51-Management of Precious Metals § 109-27.5106 Precious metals pool....

  1. 41 CFR 109-27.5106 - Precious metals pool.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 41 Public Contracts and Property Management 3 2013-07-01 2013-07-01 false Precious metals pool. 109-27.5106 Section 109-27.5106 Public Contracts and Property Management Federal Property Management...-INVENTORY MANAGEMENT 27.51-Management of Precious Metals § 109-27.5106 Precious metals pool....

  2. 41 CFR 109-1.5108-4 - Precious metals.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 41 Public Contracts and Property Management 3 2014-01-01 2014-01-01 false Precious metals. 109-1....51-Personal Property Management Standards and Practices § 109-1.5108-4 Precious metals. Perpetual inventory records are to be maintained for precious metals....

  3. 41 CFR 109-1.5108-4 - Precious metals.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 41 Public Contracts and Property Management 3 2011-01-01 2011-01-01 false Precious metals. 109-1....51-Personal Property Management Standards and Practices § 109-1.5108-4 Precious metals. Perpetual inventory records are to be maintained for precious metals....

  4. 41 CFR 109-27.5103 - Precious Metals Control Officer.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... hypo solution and scrap film in accordance with 41 CFR 101-45.10 and § 109-45.10 of this chapter. (j... 41 Public Contracts and Property Management 3 2013-07-01 2013-07-01 false Precious Metals Control... PROCUREMENT 27-INVENTORY MANAGEMENT 27.51-Management of Precious Metals § 109-27.5103 Precious Metals...

  5. 41 CFR 109-27.5103 - Precious Metals Control Officer.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... hypo solution and scrap film in accordance with 41 CFR 101-45.10 and § 109-45.10 of this chapter. (j... 41 Public Contracts and Property Management 3 2012-01-01 2012-01-01 false Precious Metals Control... PROCUREMENT 27-INVENTORY MANAGEMENT 27.51-Management of Precious Metals § 109-27.5103 Precious Metals...

  6. 41 CFR 109-27.5103 - Precious Metals Control Officer.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... hypo solution and scrap film in accordance with 41 CFR 101-45.10 and § 109-45.10 of this chapter. (j... 41 Public Contracts and Property Management 3 2014-01-01 2014-01-01 false Precious Metals Control... PROCUREMENT 27-INVENTORY MANAGEMENT 27.51-Management of Precious Metals § 109-27.5103 Precious Metals...

  7. 41 CFR 109-27.5106 - Precious metals pool.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false Precious metals pool. 109-27.5106 Section 109-27.5106 Public Contracts and Property Management Federal Property Management...-INVENTORY MANAGEMENT 27.51-Management of Precious Metals § 109-27.5106 Precious metals pool....

  8. 41 CFR 109-27.5103 - Precious Metals Control Officer.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... hypo solution and scrap film in accordance with 41 CFR 101-45.10 and § 109-45.10 of this chapter. (j... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false Precious Metals Control... PROCUREMENT 27-INVENTORY MANAGEMENT 27.51-Management of Precious Metals § 109-27.5103 Precious Metals...

  9. 41 CFR 109-1.5108-4 - Precious metals.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false Precious metals. 109-1....51-Personal Property Management Standards and Practices § 109-1.5108-4 Precious metals. Perpetual inventory records are to be maintained for precious metals....

  10. Recovery of precious metals in space

    NASA Technical Reports Server (NTRS)

    Freiser, H.

    1990-01-01

    This program is proceeding along the lines compatible with the objective of developing feasible separation and recovery processes for precious metals in a space environment. Efficient, compact, solvent extraction systems (both single and multistage) capable of high selectivity and rapid equilibration that are based on chelate and ion pair complexes are being explored. Two research projects were undertaken: (1) study of the time-dependent aspects of the formation of Pd(2) extractable chelate complexes; and (2) development of a multistage countercurrent distribution process for the separation and recovery of Pd(2) and Pt(2) ions.

  11. 48 CFR 945.607-2 - Recovering precious metals.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... or radioactively contaminated, except for silver. Only high grade nonradioactively contaminated silver should be reported to the precious metals pool. The Oak Ridge Operations Office is responsible...

  12. Precious Metal Recovery from Fuel Cell MEA's

    SciTech Connect

    Lawrence Shore

    2004-04-25

    In 2003, Engelhard Corporation received a DOE award to develop a cost-effective, environmentally friendly approach to recover Pt from fuel cell membrane electrode assemblies (MEA’s). The most important precious metal used in fuel cells is platinum, but ruthenium is also added to the anode electrocatalyst if CO is present in the hydrogen stream. As part of the project, a large number of measurements of Pt and Ru need to be made. A low-cost approach to measuring Pt is using the industry standard spectrophotometric measurement of Pt complexed with stannous chloride. The interference of Ru can be eliminated by reading the Pt absorbance at 450 nm. Spectrophotometric methods for measuring Ru, while reported in the literature, are not as robust. This paper will discuss the options for measuring Pt and Ru using the method of UV-VIS spectrophotometry

  13. Recovery of precious metals from space

    NASA Technical Reports Server (NTRS)

    Freiser, Henry

    1991-01-01

    The overall objective is to develop efficient and economical separation and recovery methods for the platinum group and other precious metals. The separation of Pd(II) from Pt(II), Ir(III), and Rh(III) with trioctylphosphine oxide (TOPO) in heptane using centrifugal partition chromatography (CPC) was investigated. Activities to achieve this objective focussed on selection and evaluation of extraction systems for the PGM and modification of selected systems for multistage operation with a view to scaling up to desired macro levels. On the basis of preliminary evaluation of a series of simple metal complexing agents and chelating agents, the TOPO in heptane was selected as a likely system for isolating of Pd(II) and Pt(II) from the other PGM. A multistage apparatus capable of configuration as a simple rugged device, a centrifugal partition chromatograph (CPC), was shown to be effective. The extraction of Pd(II) was studied by CPC and batch solvent extraction. The distribution ratios for Pd(II) determined by both methods agree well. In low HCl concentrations (less than 0.1 M), the extracted species was PdCl2.(TOPO)2, irrespective of the chloride concentration, while at acid concentrations above 0.1 M, the Pd was extracted as the ion pair, 2(TOPO.H+).(PdCl4)2-. Base line separation of Pd(II) and Pt(II) in CPC was obtained under a variety of chloride and HCl concentration. It was demonstrated that the efficiency of CPC for metal separation was limited by chemical kinetic factors rather than instrumental factors, strongly suggesting that dramatic improvements can be achieved by studying reaction kinetics of formation and dissociation of the extractable metal complex.

  14. Methods for recovering precious metals from industrial waste

    NASA Astrophysics Data System (ADS)

    Canda, L.; Heput, T.; Ardelean, E.

    2016-02-01

    The accelerated rate of industrialization increases the demand for precious metals, while high quality natural resources are diminished quantitatively, with significant operating costs. Precious metals recovery can be successfully made from waste, considered to be secondary sources of raw material. In recent years, concerns and interest of researchers for more increasing efficient methods to recover these metals, taking into account the more severe environmental protection legislation. Precious metals are used in a wide range of applications, both in electronic and communications equipment, spacecraft and jet aircraft engines and for mobile phones or catalytic converters. The most commonly recovered precious metals are: gold from jewellery and electronics, silver from X- ray films and photographic emulsions, industrial applications (catalysts, batteries, glass/mirrors), jewellery; platinum group metals from catalytic converters, catalysts for the refining of crude oil, industrial catalysts, nitric acid manufacturing plant, the carbon-based catalyst, e-waste. An important aspect is the economic viability of recycling processes related to complex waste flows. Hydrometallurgical and pyrometallurgical routes are the most important ways of processing electrical and electronic equipment waste. The necessity of recovering precious metals has opened new opportunities for future research.

  15. 40 CFR 471.40 - Applicability; description of the precious metals forming subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... precious metals forming subcategory. 471.40 Section 471.40 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) NONFERROUS METALS FORMING AND METAL POWDERS POINT SOURCE CATEGORY Precious Metals Forming Subcategory § 471.40...

  16. 40 CFR 471.40 - Applicability; description of the precious metals forming subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... precious metals forming subcategory. 471.40 Section 471.40 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) NONFERROUS METALS FORMING AND METAL POWDERS POINT SOURCE CATEGORY Precious Metals Forming Subcategory § 471.40...

  17. Characterisation of the surface of freshly prepared precious metal catalysts.

    PubMed

    Parker, Stewart F; Adroja, Devashibhai; Jiménez-Ruiz, Mónica; Tischer, Markus; Möbus, Konrad; Wieland, Stefan D; Albers, Peter

    2016-07-14

    A combination of electron microscopy, X-ray and neutron spectroscopies and computational methods has provided new insights into the species present on the surface of freshly prepared precious metal catalysts. The results show that in all cases, at least half of the surface is metallic or nearly so, with the remainder covered by oxygen, largely as hydroxide. Water is also present and is strongly held; weeks of pumping under high vacuum is insufficient to remove it. The hydroxyls are reactive as shown by their reaction with or displacement by CO and can be removed by hydrogenation. This clearly has implications for how precious metal catalysts are activated after preparation. PMID:26986759

  18. 40 CFR 421.260 - Applicability: Description of the secondary precious metals subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... secondary precious metals subcategory. 421.260 Section 421.260 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Secondary Precious Metals Subcategory § 421.260 Applicability: Description of the...

  19. 40 CFR 421.260 - Applicability: Description of the secondary precious metals subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... secondary precious metals subcategory. 421.260 Section 421.260 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Secondary Precious Metals Subcategory § 421.260 Applicability: Description of the...

  20. 40 CFR 421.260 - Applicability: Description of the secondary precious metals subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... secondary precious metals subcategory. 421.260 Section 421.260 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Secondary Precious Metals Subcategory § 421.260 Applicability: Description of the...

  1. 40 CFR 421.260 - Applicability: Description of the secondary precious metals subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... secondary precious metals subcategory. 421.260 Section 421.260 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Secondary Precious Metals Subcategory § 421.260 Applicability: Description of the...

  2. 41 CFR 109-27.5103 - Precious Metals Control Officer.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... returns to, the DOE precious metals pool. (i) Conducting a program for the recovery of silver from used hypo solution and scrap film in accordance with 41 CFR 101-45.10 and § 109-45.10 of this chapter. (j) Preparing and submitting of the annual report on recovery of silver from used hypo solution and scrap...

  3. Recovery of precious metals from military electronic components

    SciTech Connect

    Gundiler, I.H.; Lutz, J.D.; Neiswander, P.G.

    1996-09-01

    Sandia National Laboratories developed a process to identify and remove the hazardous sub-components from dismantled weapons components utilizing real-time radiography and abrasive water-jet cutting. The components were then crushed, granulated, screened, and separated into an aluminium and a precious-and-base-metals fraction using air-tables. Plastics were further cleaned for disposal as non- hazardous waste.

  4. Precious-Metal Salt Coatings for Detecting Hydrazines

    NASA Technical Reports Server (NTRS)

    Dee, Louis A.; Greene, Benjamin

    2004-01-01

    Substrates coated with a precious-metal salt KAuCl4 have been found to be useful for detecting hydrazine vapors in air at and above a concentration of the order of 0.01 parts per million (ppm). Upon exposure to air containing a sufficient amount of hydrazine for a sufficient time, the coating material undergoes a visible change in color.

  5. Converting practices at the stillwater precious metals smelter

    NASA Astrophysics Data System (ADS)

    Roset, Greg K.; Matousek, Jan W.; Marcantonio, Paul J.

    1992-04-01

    At the Stillwater Mining Company's precious metals smelter in Columbus, Montana, flotation concentrates containing copper, nickel, and platinum-group metals are smelted in a submerged-arc electric furnace. The matte, containing 30% copper plus nickel, is granulated, dried, remelted in a top-blown rotary converter, and blown with oxygen to "white metal" containing approximately 75% copper plus nickel and 2.5% precious metals. For the first month of converter operation (July 1990), conventional fluxing with quartz was practiced. An excessive number of slag foams and heavy accretion formation at the mouth of the converter led to a switch to lime fluxing as a replacement for silica. This resulted in eliminating slag foams and decreasing accretion build-up. It is believed that the Stillwater works is the only commercial smelter in the world following this practice.

  6. 40 CFR 421.250 - Applicability: Description of the primary precious metals and mercury subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... primary precious metals and mercury subcategory. 421.250 Section 421.250 Protection of Environment... POINT SOURCE CATEGORY Primary Precious Metals and Mercury Subcategory § 421.250 Applicability: Description of the primary precious metals and mercury subcategory. The provisions of this subpart...

  7. 40 CFR 421.250 - Applicability: Description of the primary precious metals and mercury subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... primary precious metals and mercury subcategory. 421.250 Section 421.250 Protection of Environment... POINT SOURCE CATEGORY Primary Precious Metals and Mercury Subcategory § 421.250 Applicability: Description of the primary precious metals and mercury subcategory. The provisions of this subpart...

  8. 40 CFR 421.250 - Applicability: Description of the primary precious metals and mercury subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... primary precious metals and mercury subcategory. 421.250 Section 421.250 Protection of Environment... POINT SOURCE CATEGORY Primary Precious Metals and Mercury Subcategory § 421.250 Applicability: Description of the primary precious metals and mercury subcategory. The provisions of this subpart...

  9. 41 CFR 109-45.1002-3 - Precious metals recovery program monitor.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 41 Public Contracts and Property Management 3 2013-07-01 2013-07-01 false Precious metals recovery program monitor. 109-45.1002-3 Section 109-45.1002-3 Public Contracts and Property Management Federal... Metals § 109-45.1002-3 Precious metals recovery program monitor. The DPMO shall be the precious...

  10. 41 CFR 109-45.1002-3 - Precious metals recovery program monitor.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 41 Public Contracts and Property Management 3 2012-01-01 2012-01-01 false Precious metals recovery program monitor. 109-45.1002-3 Section 109-45.1002-3 Public Contracts and Property Management Federal... Metals § 109-45.1002-3 Precious metals recovery program monitor. The DPMO shall be the precious...

  11. 41 CFR 109-45.1002-3 - Precious metals recovery program monitor.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 41 Public Contracts and Property Management 3 2011-01-01 2011-01-01 false Precious metals recovery program monitor. 109-45.1002-3 Section 109-45.1002-3 Public Contracts and Property Management Federal... Metals § 109-45.1002-3 Precious metals recovery program monitor. The DPMO shall be the precious...

  12. 40 CFR 413.20 - Applicability: Description of the electroplating of precious metals subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... electroplating of precious metals subcategory. 413.20 Section 413.20 Protection of Environment ENVIRONMENTAL... Electroplating of Precious Metals Subcategory § 413.20 Applicability: Description of the electroplating of precious metals subcategory. The provisions of this subpart apply to discharges of process...

  13. 40 CFR 413.20 - Applicability: Description of the electroplating of precious metals subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... electroplating of precious metals subcategory. 413.20 Section 413.20 Protection of Environment ENVIRONMENTAL... Electroplating of Precious Metals Subcategory § 413.20 Applicability: Description of the electroplating of precious metals subcategory. The provisions of this subpart apply to discharges of process...

  14. 41 CFR 109-45.1002-3 - Precious metals recovery program monitor.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 41 Public Contracts and Property Management 3 2014-01-01 2014-01-01 false Precious metals recovery program monitor. 109-45.1002-3 Section 109-45.1002-3 Public Contracts and Property Management Federal... Metals § 109-45.1002-3 Precious metals recovery program monitor. The DPMO shall be the precious...

  15. 40 CFR 413.20 - Applicability: Description of the electroplating of precious metals subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... electroplating of precious metals subcategory. 413.20 Section 413.20 Protection of Environment ENVIRONMENTAL... Electroplating of Precious Metals Subcategory § 413.20 Applicability: Description of the electroplating of precious metals subcategory. The provisions of this subpart apply to discharges of process...

  16. 41 CFR 109-45.1002-3 - Precious metals recovery program monitor.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false Precious metals recovery program monitor. 109-45.1002-3 Section 109-45.1002-3 Public Contracts and Property Management Federal... Metals § 109-45.1002-3 Precious metals recovery program monitor. The DPMO shall be the precious...

  17. 40 CFR 413.20 - Applicability: Description of the electroplating of precious metals subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... electroplating of precious metals subcategory. 413.20 Section 413.20 Protection of Environment ENVIRONMENTAL... Electroplating of Precious Metals Subcategory § 413.20 Applicability: Description of the electroplating of precious metals subcategory. The provisions of this subpart apply to discharges of process...

  18. 40 CFR 421.250 - Applicability: Description of the primary precious metals and mercury subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... POINT SOURCE CATEGORY Primary Precious Metals and Mercury Subcategory § 421.250 Applicability: Description of the primary precious metals and mercury subcategory. The provisions of this subpart are... primary precious metals and mercury subcategory. 421.250 Section 421.250 Protection of...

  19. 40 CFR 421.250 - Applicability: Description of the primary precious metals and mercury subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... POINT SOURCE CATEGORY Primary Precious Metals and Mercury Subcategory § 421.250 Applicability: Description of the primary precious metals and mercury subcategory. The provisions of this subpart are... primary precious metals and mercury subcategory. 421.250 Section 421.250 Protection of...

  20. EXPLORATION STRATEGY FOR HOT-SPRING PRECIOUS-METAL DEPOSITS.

    USGS Publications Warehouse

    Berger, Byron R.; Adams, Samuel S.

    1984-01-01

    The discovery of economic precious-metal deposits related to physical-chemical processes in the near-surface portions of high-temperature hot-spring systems has led to intensive exploration efforts for this deposit type. To increase the probability of success, these exploration programs should (1) be based on the most important visually recognizable or readily measurable deposit-model criteria; (2) be able to identify specific targets within the best search areas; and (3) be able to rank the order of priority among the targets. We propose a process-recognition exploration strategy for hot-spring deposits that has been developed from data from precious-metal occurrences at several localities in the western United States. The exploration model is based on the degree to which recognizable geologic and geochemical criteria are favorable or unfavorable to the occurrence of an economic deposit, either through their presence or absence.

  1. Recovery and separation of precious metals from space

    NASA Technical Reports Server (NTRS)

    Freiser, H.; Muralidharan, S.

    1992-01-01

    During the past year a viable procedure centered around centrifugal partition chromatography (CPC), a multistage liquid-liquid partitioning technique for the separation of precious metals (Pt, Pd, Rh, Ir, Os, Ru), was developed. Stable and inexpensive ligands that can be readily recycled to achieve the separations of the precious metals were identified. The separation methods developed so far yield three separate fractions: Pt, Pd, and Rh-Ir. The Rh-Ir pair can be separated in a subsequent run. The total amount of precious metals separated in a single experiment varied from 1 to 50 mg. The factors affecting the efficiencies of these separations were studied. The kinetics of the decomposition of the complex and the ion pair have a major bearing on these efficiencies, with slow kinetics resulting in poor efficiencies. The methods for the improvement of the efficiencies were also investigated. For example, significant improvement in the efficiencies and separation times for Pt and Pd were achieved by the use of chloride gradient in the mobile phase. Two papers were published and talks were presented on our work at the FACSS meeting in Anaheim, Oct. 1991, and at the Pittsburgh Conference in New Orleans, Mar. 1992.

  2. Phase Behavior of Pseudobinary Precious Metal-Carbide Systems

    SciTech Connect

    Gregoire, John M.; Tague, Michele E.; Smith, Eva H.; Dale, Darren; DiSalvo, Francis J.; Abruña, Héctor D.; Hennig, Richard G.; van Dover, R. Bruce

    2010-11-15

    Transition metal carbides exhibit a variety of interesting material properties, including electrochemical stability. When combined with precious metals, Ta and W carbides have shown promise as fuel cell electrode materials; yet, the phase behavior of these precious metal-carbide systems is largely unexplored. We investigated P-M-C phase behavior with P = Pt, Pd, and Ru and M = Ta and W using composition spread thin films. We attained limited control of the deposited carbide phase through variation of the sputter atmosphere and demonstrated decreased corrosion of W-C materials with increasing C content. A high-throughput X-ray diffraction and X-ray fluorescence experiment was employed for thin film characterization, which revealed solubility of Pt, Pd, and Ru in cubic WC. Density functional calculations of the lattice parameter dependence on carbon concentration enabled the determination of carbon concentration from the X-ray data as a function of transition metal stoichiometry. Our measurement of variations in the C stoichiometry and evolution of thin film texture with transition metal composition yielded surprising results. We detail how the combination of the composition spread technique, the high-throughput thin film characterization, and the density functional modeling of ternary carbide alloys provided a deep understanding of the chemical systems.

  3. Rationalization of interactions in precious metal/ceria catalysts using the d-band center model.

    PubMed

    Acerbi, N; Tsang, S C Edman; Jones, G; Golunski, S; Collier, P

    2013-07-22

    A correlation between ceria reducibility and the precious-metal d-band center is reported for ceria-supported precious-metal catalysts. The results could provide the missing link to fully explain the occurrence of strong metal-support interaction (SMSI) and hydrogen spillover in catalysts that consist of dispersed metals in contact with reducible metal oxides. PMID:23780919

  4. 78 FR 32477 - ASA Gold and Precious Metals Limited; Notice of Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-30

    ... COMMISSION ASA Gold and Precious Metals Limited; Notice of Application May 22, 2013. AGENCY: Securities and... Company Act of 1940 (the ``Act''). ] SUMMARY: Summary of Application: Applicant, ASA Gold and Precious... gold and other precious minerals. To this end, ASA's management is seeking to take advantage...

  5. 40 CFR 471.40 - Applicability; description of the precious metals forming subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... precious metals forming subcategory. 471.40 Section 471.40 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS NONFERROUS METALS FORMING AND METAL POWDERS POINT SOURCE CATEGORY Precious Metals Forming Subcategory § 471.40 Applicability; description of...

  6. Impact of global financial crisis on precious metals returns: An application of ARCH and GARCH methods

    NASA Astrophysics Data System (ADS)

    Ismail, Mohd Tahir; Abdullah, Nurul Ain; Abdul Karim, Samsul Ariffin

    2013-04-01

    This paper is focusing on seeing the resilient of precious metals returns in facing the global financial crisis and provides a new guide for the investors before making investment decisions on precious metals. Four types of precious metals returns which are the variables selected in this study. The precious metals are gold, silver, bronze and platinum. All the variables are transferred to natural logarithm (ln). Daily data over the period 2 January 1995 to 30 December 2011 is used. Unit root tests that involve Augmented Dickey-Fuller (ADF) and Kwiatkowski-Phillips-Schmidt-Shin (KPSS) tests have been employed in determining the stationarity of the variables. Autoregressive Conditional Heteroscedasticity (ARCH) and Generalized Autoregressive Conditional Heteroscedasticity (GARCH) methods have been applied in measuring the impact of global financial crisis on precious metals returns. The result shows that investing in platinum is less risky compared to the other precious metals because it is not influence by the crisis period.

  7. The removal of precious metals by conductive polymer filtration

    SciTech Connect

    Cournoyer, M.E.

    1996-10-01

    The growing demand for platinum-group metals (PGM) within the DOE complex and in industry, the need for modern and clean processes, and the increasing volume of low-grade material for secondary PGM recovery has a direct impact on the industrial practice of recovering and refining precious metals. There is a tremendous need for advanced metal ion recovery and waste minimization techniques, since the currently used method of precipitation-dissolution is inadequate. Los Alamos has an integrated program in ligand-design and separations chemistry which has developed and evaluated a series of water- soluble metal-binding polymers for recovering actinides and toxic metals from variety of process streams. A natural extension of this work is to fabricate these metal-selective polymers into membrane based separation unites, i.e., hollow-fiber membranes. In the present investigation, the material for a novel hollow-fiber membrane is characterized and its selectivity for PGM reported. Energy and waste savings and economic competitiveness are also described.

  8. Relationship between amorphous silica and precious metal in quartz veins

    NASA Astrophysics Data System (ADS)

    Harrichhausen, N.; Rowe, C. D.; Board, W. S.; Greig, C. J.

    2015-12-01

    Super-saturation of silica is common in fault fluids, due to pressure changes associated with fracture, fault slip, or temperature gradients in hydrothermal systems. These mechanisms lead to precipitation of amorphous silica, which will recrystallize to quartz under typical geologic conditions. These conditions may also promote the saturation of precious metals, such as gold, and the precipitation of nanoparticles. Previous experiments show that charged nanoparticles of gold can attach to the surface of amorphous silica nanoparticles. Thus, gold and silica may be transported as a colloid influencing mineralization textures during amorphous silica recrystallization to quartz. This may enrich quartz vein hosted gold deposits, but the instability of hydrous silica during subsequent deformation means that the microstructural record of precipitation of gold is lost. We investigate a recent, shallow auriferous hydrothermal system at Dixie Valley, Nevada to reveal the nano- to micro-scale relationships between gold and silica in fresh veins. Fault slip surfaces at Dixie Valley exhibit layers of amorphous silica with partial recrystallization to quartz. Transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS) show amorphous silica can contain a few wt. % gold while areas recrystallized to quartz are barren. At the Jurassic Brucejack deposit in British Columbia, Canada we observe the cryptocrystalline quartz textures that may indicate recrystallization from amorphous silica within quartz-carbonate veins containing high grade gold. Comb quartz within syntaxial veins, vugs, and coating breccia clasts indicate structural dilation. Vein geometry is investigated to determine relative importance of fault slip in creating dilational sites. By comparing quartz-carbonate veins from the Dixie Valley to Brucejack, we can determine whether amorphous silica formed in different environments show similar potential to affect precious metal mineralization.

  9. 48 CFR 1845.607-2 - Recovering precious metals. (NASA supplements paragraph (b)).

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false Recovering precious metals. (NASA supplements paragraph (b)). 1845.607-2 Section 1845.607-2 Federal Acquisition Regulations System..., Redistribution, and Disposal of Contractor Inventory 1845.607-2 Recovering precious metals. (NASA...

  10. 48 CFR 1845.607-2 - Recovering precious metals. (NASA supplements paragraph (b)).

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 6 2012-10-01 2012-10-01 false Recovering precious metals. (NASA supplements paragraph (b)). 1845.607-2 Section 1845.607-2 Federal Acquisition Regulations System..., Redistribution, and Disposal of Contractor Inventory 1845.607-2 Recovering precious metals. (NASA...

  11. 48 CFR 1845.607-2 - Recovering precious metals. (NASA supplements paragraph (b)).

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false Recovering precious metals. (NASA supplements paragraph (b)). 1845.607-2 Section 1845.607-2 Federal Acquisition Regulations System..., Redistribution, and Disposal of Contractor Inventory 1845.607-2 Recovering precious metals. (NASA...

  12. 48 CFR 1845.607-2 - Recovering precious metals. (NASA supplements paragraph (b)).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Recovering precious metals. (NASA supplements paragraph (b)). 1845.607-2 Section 1845.607-2 Federal Acquisition Regulations System..., Redistribution, and Disposal of Contractor Inventory 1845.607-2 Recovering precious metals. (NASA...

  13. 48 CFR 1845.607-2 - Recovering precious metals. (NASA supplements paragraph (b)).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 6 2013-10-01 2013-10-01 false Recovering precious metals. (NASA supplements paragraph (b)). 1845.607-2 Section 1845.607-2 Federal Acquisition Regulations System..., Redistribution, and Disposal of Contractor Inventory 1845.607-2 Recovering precious metals. (NASA...

  14. 77 FR 50056 - Guides for the Jewelry, Precious Metals, and Pewter Industries

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-20

    ... deadline for filing comments. \\1\\ 77 FR 39201 (July 2, 2012). A trade association representing jewelry... CFR PART 23 Guides for the Jewelry, Precious Metals, and Pewter Industries AGENCY: Federal Trade... Jewelry, Precious Metals, and Pewter Industries. DATES: Comments must be received on or before...

  15. Simplified process for leaching precious metals from fuel cell membrane electrode assemblies

    DOEpatents

    Shore, Lawrence; Matlin, Ramail

    2009-12-22

    The membrane electrode assemblies of fuel cells are recycled to recover the catalyst precious metals from the assemblies. The assemblies are cryogenically embrittled and pulverized to form a powder. The pulverized assemblies are then mixed with a surfactant to form a paste which is contacted with an acid solution to leach precious metals from the pulverized membranes.

  16. 41 CFR 109-45.1003 - Recovery of silver from precious metals bearing materials.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 41 Public Contracts and Property Management 3 2013-07-01 2013-07-01 false Recovery of silver from... of Precious Metals § 109-45.1003 Recovery of silver from precious metals bearing materials. The... establishment and maintenance of a program for silver recovery from used hypo solution and scrap film....

  17. 41 CFR 109-45.1003 - Recovery of silver from precious metals bearing materials.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 41 Public Contracts and Property Management 3 2012-01-01 2012-01-01 false Recovery of silver from... of Precious Metals § 109-45.1003 Recovery of silver from precious metals bearing materials. The... establishment and maintenance of a program for silver recovery from used hypo solution and scrap film....

  18. 41 CFR 109-45.1003 - Recovery of silver from precious metals bearing materials.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false Recovery of silver from... of Precious Metals § 109-45.1003 Recovery of silver from precious metals bearing materials. The... establishment and maintenance of a program for silver recovery from used hypo solution and scrap film....

  19. 41 CFR 109-45.1003 - Recovery of silver from precious metals bearing materials.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 41 Public Contracts and Property Management 3 2011-01-01 2011-01-01 false Recovery of silver from... of Precious Metals § 109-45.1003 Recovery of silver from precious metals bearing materials. The... establishment and maintenance of a program for silver recovery from used hypo solution and scrap film....

  20. 41 CFR 109-45.1003 - Recovery of silver from precious metals bearing materials.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 41 Public Contracts and Property Management 3 2014-01-01 2014-01-01 false Recovery of silver from... of Precious Metals § 109-45.1003 Recovery of silver from precious metals bearing materials. The... establishment and maintenance of a program for silver recovery from used hypo solution and scrap film....

  1. Replacing precious metals with carbide catalysts for hydrogenation reactions

    DOE PAGESBeta

    Ruijun, Hou; Chen, Jingguang G.; Chang, Kuan; Wang, Tiefeng

    2015-03-03

    Molybdenum carbide (Mo₂C and Ni/Mo₂C) catalysts were compared with Pd/SiO₂ for the hydrogenation of several diene molecules, 1,3- butadiene, 1,3- and 1,4-cyclohexadiene (CHD). Compared to Pd/SiO₂, Mo₂C showed similar hydrogenation rate for 1,3-butadiene and 1,3-CHD and even higher rate for 1,4-CHD, but with significant deactivation rate for 1,3-CHD hydrogenation. However, the hydrogenation activity of Mo₂C could be completely regenerated by H₂ treatment at 723 K for the three molecules. The Ni modified Mo₂C catalysts retained similar activity for 1,3-butadiene hydrogenation with significantly enhanced selectivity for 1-butene production. The 1-butene selectivity increased with increasing Ni loading below 15%. Among the Nimore » modified Mo₂C catalysts, 8.6%Ni/Mo₂C showed the highest selectivity to 1-butene, which was even higher selectivity than that over Pd/SiO₂. Compared to Pd/SiO₂, both Mo₂C and Ni/Mo₂C showed combined advantages in hydrogenation activity and catalyst cost reduction, demonstrating the potential to use less expensive carbide catalysts to replace precious metals for hydrogenation reactions.« less

  2. Replacing precious metals with carbide catalysts for hydrogenation reactions

    SciTech Connect

    Ruijun, Hou; Chen, Jingguang G.; Chang, Kuan; Wang, Tiefeng

    2015-03-03

    Molybdenum carbide (Mo₂C and Ni/Mo₂C) catalysts were compared with Pd/SiO₂ for the hydrogenation of several diene molecules, 1,3- butadiene, 1,3- and 1,4-cyclohexadiene (CHD). Compared to Pd/SiO₂, Mo₂C showed similar hydrogenation rate for 1,3-butadiene and 1,3-CHD and even higher rate for 1,4-CHD, but with significant deactivation rate for 1,3-CHD hydrogenation. However, the hydrogenation activity of Mo₂C could be completely regenerated by H₂ treatment at 723 K for the three molecules. The Ni modified Mo₂C catalysts retained similar activity for 1,3-butadiene hydrogenation with significantly enhanced selectivity for 1-butene production. The 1-butene selectivity increased with increasing Ni loading below 15%. Among the Ni modified Mo₂C catalysts, 8.6%Ni/Mo₂C showed the highest selectivity to 1-butene, which was even higher selectivity than that over Pd/SiO₂. Compared to Pd/SiO₂, both Mo₂C and Ni/Mo₂C showed combined advantages in hydrogenation activity and catalyst cost reduction, demonstrating the potential to use less expensive carbide catalysts to replace precious metals for hydrogenation reactions.

  3. Matrix elimination method for the determination of precious metals in ores using electrothermal atomic absorption spectrometry.

    PubMed

    Salih, Bekir; Celikbiçak, Omür; Döker, Serhat; Doğan, Mehmet

    2007-03-28

    Poly(N-(hydroxymethyl)methacrylamide)-1-allyl-2-thiourea) hydrogels, poly(NHMMA-ATU), were synthesized by gamma radiation using (60)Co gamma source in the ternary mixture of NHMMA-ATU-H(2)O. These hydrogels were used for the specific gold, silver, platinum and palladium recovery, pre-concentration and matrix elimination from the solutions containing trace amounts of precious metal ions. Elimination of inorganic matrices such as different transition and heavy metal ions, and anions was performed by adjusting the solution pH to 0.5 that was the selective adsorption pH of the precious metal ions. Desorption of the precious metal ions was performed by using 0.8 M thiourea in 3M HCl as the most efficient desorbing agent with recovery values more than 95%. In the desorption medium, thiourea effect on the atomic signal was eliminated by selecting proper pyrolysis and atomization temperatures for all precious metal ions. Precision and the accuracy of the results were improved in the graphite furnace-atomic absorption spectrometer (GFAAS) measurements by applying the developed matrix elimination method performing the adsorption at pH 0.5. Pre-concentration factors of the studied precious metal ions were found to be at least 1000-fold. Detection limits of the precious metal ions were found to be less than 10 ng L(-1) of the all studied precious metal ions by using the proposed pre-concentration method. Determination of trace levels of the precious metals in the sea-water, anode slime, geological samples and photographic fixer solutions were performed using GFAAS clearly after applying the adsorption-desorption cycle onto the poly(NHMMA-UTU) hydrogels. PMID:17386783

  4. Permeability of precious metals to hydrogen at 2kb total pressure and elevated temperatures.

    USGS Publications Warehouse

    Chou, I.-Ming

    1986-01-01

    Permeabilities of several commonly used precious metals to hydrogen have been measured at 2kb total pressure and between 450o and 812oC by using the double-capsule oxygen buffer technique.- from Author

  5. Effective and Selective Recovery of Precious Metals by Thiourea Modified Magnetic Nanoparticles

    PubMed Central

    Lin, Tai-Lin; Lien, Hsing-Lung

    2013-01-01

    Adsorption of precious metals in acidic aqueous solutions using thiourea modified magnetic magnetite nanoparticle (MNP-Tu) was examined. The MNP-Tu was synthesized, characterized and examined as a reusable adsorbent for the recovery of precious metals. The adsorption kinetics were well fitted with pseudo second-order equation while the adsorption isotherms were fitted with both Langmuir and Freundlich equations. The maximum adsorption capacity of precious metals for MNP-Tu determined by Langmuir model was 43.34, 118.46 and 111.58 mg/g for Pt(IV), Au(III) and Pd(II), respectively at pH 2 and 25 °C. MNP-Tu has high adsorption selectivity towards precious metals even in the presence of competing ions (Cu(II)) at high concentrations. In addition, the MNP-Tu can be regenerated using an aqueous solution containing 0.7 M thiourea and 2% HCl where precious metals can be recovered in a concentrated form. It was found that the MNP-Tu undergoing seven consecutive adsorption-desorption cycles still retained the original adsorption capacity of precious metals. A reductive adsorption resulting in the formation of elemental gold and palladium at the surface of MNP-Tu was observed. PMID:23698770

  6. Corrosion behaviour of cobalt-chromium dental alloys doped with precious metals.

    PubMed

    Reclaru, Lucien; Lüthy, Heinz; Eschler, Pierre-Yves; Blatter, Andreas; Susz, Christian

    2005-07-01

    Precious metal based dental alloys generally exhibit a superior corrosion resistance, in particular enhanced resistance to pitting and crevice corrosion, compared to non-precious metal based alloys such as CoCr alloys. A new generation of Co-Cr alloys enriched with precious metals (Au, Pt, Ru) have now appeared on the market. The goal of this study was to clarify the effect of the precious metals additions on the corrosion behaviour of such alloys. Various commercial alloys with different doping levels were tested by electrochemical techniques in two different milieus based on the Fusayama artificial saliva and an electrolyte containing NaCl. Open circuit potentials, corrosion currents, polarization resistances, and crevices potentials were determined for the various alloys and completed by a coulometric analysis of the potentiodynamic curves. In addition, the microstructures were characterised by metallography and phase compositions analysed by EDX. The results show that the presence of precious metals can deteriorate the corrosion behaviour of Co-Cr alloys in a significant way. Gold doping, in particular, produces heterogeneous microstructures that are vulnerable to corrosive attack. PMID:15701364

  7. High performance, high durability non-precious metal fuel cell catalysts

    DOEpatents

    Wood, Thomas E.; Atanasoski, Radoslav; Schmoeckel, Alison K.

    2016-03-15

    This invention relates to non-precious metal fuel cell cathode catalysts, fuel cells that contain these catalysts, and methods of making the same. The fuel cell cathode catalysts are highly nitrogenated carbon materials that can contain a transition metal. The highly nitrogenated carbon materials can be supported on a nanoparticle substrate.

  8. Metal molybdate nanorods as non-precious electrocatalysts for the oxygen reduction

    NASA Astrophysics Data System (ADS)

    Wu, Tian; Zhang, Lieyu

    2015-12-01

    Development of non-precious electrocatalysts with applicable electrocatalytic activity towards the oxygen reduction reaction (ORR) is important to fulfill broad-based and large-scale applications of metal/air batteries and fuel cells. Herein, nickel and cobalt molybdates with uniform nanorod morphology are synthesized using a facile one-pot hydrothermal method. The ORR activity of the prepared metal molybdate nanorods in alkaline media are investigated by using cyclic voltammetry (CV), linear sweep voltammetry (LSV) and chronoamperomety in rotating disk electrode (RDE) techniques. The present study suggests that the prepared metal molybdate nanorods exhibit applicable electrocatalytic activities towards the ORR in alkaline media, promising the applications as non-precious cathode in fuel cells and metal-air batteries.

  9. A Precious Metal-Free Electroless Technique for the Deposition of Copper on Carbon Fibers

    NASA Astrophysics Data System (ADS)

    Che, Dehui; Yao, Guangchun; Cao, Zhuokun

    2012-11-01

    This article introduces a new technique of electroless copper deposition on carbon fibers in the absence of precious metal as the catalyst. Copper layers were electrolessly deposited on the surface of carbon fiber without using the conventional palladium or silver catalyst to initiate redox reactions leading to metallization. This new technique shows that nickel seeds can serve as excellent catalysts to expedite the redox reactions. By performing experiments, parameters such as activation temperature, nickel ion concentration, and pH value were optimized, and an orbicular copper plating layer of carbon fiber was obtained in the copper sulfate salt-based conventional electroless solution. The surface morphology of copper coating was characterized by scanning electron microscopy and X-ray diffraction. The results indicate that uniform and smooth copper coating could be obtained by the new precious-metal free activation process. The resulting copper coating thickness is about 1 μm.

  10. Precious metal catalysts with oxygen-ion conducting support

    SciTech Connect

    Ganguli, P.S.; Sundaresan, S.

    1993-08-03

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

  11. Non-precious metal catalysts prepared from precursor comprising cyanamide

    DOEpatents

    Chung, Hoon Taek; Zelenay, Piotr

    2015-10-27

    Catalyst comprising graphitic carbon and methods of making thereof; said graphitic carbon comprising a metal species, a nitrogen-containing species and a sulfur containing species. A catalyst for oxygen reduction reaction for an alkaline fuel cell was prepared by heating a mixture of cyanamide, carbon black, and a salt selected from an iron sulfate salt and an iron acetate salt at a temperature of from about 700.degree. C. to about 1100.degree. C. under an inert atmosphere. Afterward, the mixture was treated with sulfuric acid at elevated temperature to remove acid soluble components, and the resultant mixture was heated again under an inert atmosphere at the same temperature as the first heat treatment step.

  12. Potentiometric titration of gold, platinum, and some other precious metals

    SciTech Connect

    Selig, W.S.

    1991-02-04

    Gold, platinum, and several other platinum metals can be determined by titration with cetylpyridinium chloride (CPC). CPC forms a precipitate with AuCl{sub 4}{sup {minus}} and PtCl{sub 6}{sup 2{minus}}. Differentiation of AuCl{sub 4{minus}} and PtCl{sub 6}{sup 2{minus}} with this titrant is not possible; however, their sum can be determined. Titration with tetraphenylarsonium chloride at pH 1 is selective for tetrachloroaurate, which thus can be determined in the presence of hexachloroplatinate. Hexachloroosmate(IV), tetrachloroplatinite(II), tetrachloropalladate(II), hexachloropalladate(IV), and hexachloroiridate(IV) can also be determined potentiometrically vs. CPC. The indicating electrode is prepared by coating a spectroscopic graphite rod with a solution of poly(vinyl chloride) (PVC) and dioctylphthalate (DOP) in tetrahydrofuran (THF). Gold in gold cyanide plating baths and in potassium aurocyanide can be determined by potentiometric titration vs standard silver nitrate, using a silver ion-selective indicating electrode. The monovalent gold need not be converted to the trivalent state with aqua regia, resulting in a considerable saving of time and effort. Free cyanide and aurocyanide can be titrated sequentially by this method. Chloride does not interfere and can, in fact, also be sequentially determined. 17 refs., 2 figs., 3 tabs.

  13. Market value of asteroidal precious metals in an age of diminishing terrestrial resources

    USGS Publications Warehouse

    Kargel, Jeffrey S.

    1996-01-01

    In the next century Mankind may have to choose from two options for our supply and usage of some nonrenewable natural resources, such as gold, platinum metals, and fossil fuels: learn to live with diminishing supplies of these materials obtained at ever increasing economic and environmental cost, or reach into difficult places and develop new technologies to give us what we need to sustain economic growth. Either prospect faces formidable technological and economic challenges. Exploitation of asteroids for precious and strategic metals is a possible environmentally friendly remedy for impending shortages of some resources. Certain types of asteroids could completely replace terrestrial sources of platinum metals. Asteroid metal mining may become a 21st-century space industry worth ten to fifty billion dollars annually (1995 dollars). Asteroids could make the United States and other countries self sufficient in many strategic metals, and it could usher new technologies and increase our applications of existing technologies that depend on these metals.

  14. A general mechanism for stabilizing the small sizes of precious metal nanoparticles on oxide supports

    SciTech Connect

    Li, Wei-Zhen; Kovarik, Libor; Mei, Donghai; Engelhard, Mark H.; Gao, Feng; Liu, Jun; Wang, Yong; Peden, Charles HF

    2014-09-02

    We recently discovered that MgAl2O4 spinel {111} nano-facets optimally stabilize the small sizes of platinum nanoparticles even after severe high temperature aging treatments. Here we report the thermal stabilities of other precious metals with various physical and chemical properties on the MgAl2O4 spinel {111} facets, providing important new insights into the stabilization mechanisms. Besides Pt, Rh and Ir can also be successfully stabilized as small (1-3 nm) nanoparticles and even as single atomic species after extremely severe (800 °C, 1 week) oxidative aging. However, other metals either aggregate (Ru, Pd, Ag, and Au) or sublimate (Os) even during initial catalyst synthesis. On the basis of ab initio theoretical calculations and experimental observations, we rationalize that the exceptional stabilization originates from lattice matching, and the correspondingly strong attractive interactions at interfaces between the spinel {111} surface oxygens and epitaxial metals\\metal oxides. On this basis, design principles for catalyst support oxide materials that are capable in stabilizing precious metals are proposed.

  15. Analysis of precious metals at parts-per-billion levels in industrial applications

    NASA Astrophysics Data System (ADS)

    Tickner, James; O'Dwyer, Joel; Roach, Greg; Smith, Michael; Van Haarlem, Yves

    2015-11-01

    Precious metals, including gold and the platinum group metals (notable Pt, Pd and Rh), are mined commercially at concentrations of a few parts-per-million and below. Mining and processing operations demand sensitive and rapid analysis at concentrations down to about 100 parts-per-billion (ppb). In this paper, we discuss two technologies being developed to meet this challenge: X-ray fluorescence (XRF) and gamma-activation analysis (GAA). We have designed on-stream XRF analysers capable of measuring targeted elements in slurries with precisions in the 35-70 ppb range. For the past two years, two on-stream analysers have been in continuous operation at a precious metals concentrator plant. The simultaneous measurement of feed and waste stream grades provides real-time information on metal recovery, allowing changes in operating conditions and plant upsets to be detected and corrected more rapidly. Separately, we have been developing GAA for the measurement of gold as a replacement for the traditional laboratory fire-assay process. High-energy Bremsstrahlung X-rays are used to excite gold via the 197Au(γ,γ‧)197Au-M reaction, and the gamma-rays released in the decay of the meta-state are then counted. We report on work to significantly improve accuracy and detection limits.

  16. Quantifying the density and utilization of active sites in non-precious metal oxygen electroreduction catalysts.

    PubMed

    Sahraie, Nastaran Ranjbar; Kramm, Ulrike I; Steinberg, Julian; Zhang, Yuanjian; Thomas, Arne; Reier, Tobias; Paraknowitsch, Jens-Peter; Strasser, Peter

    2015-01-01

    Carbon materials doped with transition metal and nitrogen are highly active, non-precious metal catalysts for the electrochemical conversion of molecular oxygen in fuel cells, metal air batteries, and electrolytic processes. However, accurate measurement of their intrinsic turn-over frequency and active-site density based on metal centres in bulk and surface has remained difficult to date, which has hampered a more rational catalyst design. Here we report a successful quantification of bulk and surface-based active-site density and associated turn-over frequency values of mono- and bimetallic Fe/N-doped carbons using a combination of chemisorption, desorption and (57)Fe Mössbauer spectroscopy techniques. Our general approach yields an experimental descriptor for the intrinsic activity and the active-site utilization, aiding in the catalyst development process and enabling a previously unachieved level of understanding of reactivity trends owing to a deconvolution of site density and intrinsic activity. PMID:26486465

  17. Quantifying the density and utilization of active sites in non-precious metal oxygen electroreduction catalysts

    NASA Astrophysics Data System (ADS)

    Sahraie, Nastaran Ranjbar; Kramm, Ulrike I.; Steinberg, Julian; Zhang, Yuanjian; Thomas, Arne; Reier, Tobias; Paraknowitsch, Jens-Peter; Strasser, Peter

    2015-10-01

    Carbon materials doped with transition metal and nitrogen are highly active, non-precious metal catalysts for the electrochemical conversion of molecular oxygen in fuel cells, metal air batteries, and electrolytic processes. However, accurate measurement of their intrinsic turn-over frequency and active-site density based on metal centres in bulk and surface has remained difficult to date, which has hampered a more rational catalyst design. Here we report a successful quantification of bulk and surface-based active-site density and associated turn-over frequency values of mono- and bimetallic Fe/N-doped carbons using a combination of chemisorption, desorption and 57Fe Mössbauer spectroscopy techniques. Our general approach yields an experimental descriptor for the intrinsic activity and the active-site utilization, aiding in the catalyst development process and enabling a previously unachieved level of understanding of reactivity trends owing to a deconvolution of site density and intrinsic activity.

  18. Quantifying the density and utilization of active sites in non-precious metal oxygen electroreduction catalysts

    PubMed Central

    Sahraie, Nastaran Ranjbar; Kramm, Ulrike I.; Steinberg, Julian; Zhang, Yuanjian; Thomas, Arne; Reier, Tobias; Paraknowitsch, Jens-Peter; Strasser, Peter

    2015-01-01

    Carbon materials doped with transition metal and nitrogen are highly active, non-precious metal catalysts for the electrochemical conversion of molecular oxygen in fuel cells, metal air batteries, and electrolytic processes. However, accurate measurement of their intrinsic turn-over frequency and active-site density based on metal centres in bulk and surface has remained difficult to date, which has hampered a more rational catalyst design. Here we report a successful quantification of bulk and surface-based active-site density and associated turn-over frequency values of mono- and bimetallic Fe/N-doped carbons using a combination of chemisorption, desorption and 57Fe Mössbauer spectroscopy techniques. Our general approach yields an experimental descriptor for the intrinsic activity and the active-site utilization, aiding in the catalyst development process and enabling a previously unachieved level of understanding of reactivity trends owing to a deconvolution of site density and intrinsic activity. PMID:26486465

  19. A Novel Method for Depositing Precious Metal Films on Difficult Surfaces

    NASA Technical Reports Server (NTRS)

    Veitch, L. C.; Phillip, W. H.

    1994-01-01

    A guanidine-based vehicle was developed to deposit precious metal coatings on surfaces known to be difficult to coat. To demonstrate this method, a platinum coating was deposited on alumina fibers using a guanidine-platinum solution. X-ray diffraction confirmed that the only species present in the coating was platinum and that all of the carbon species had been removed upon heat treatment. SEM results showed that some porosity was present but that the coatings uniformly covered the fiber surface and adhered well to the finer.

  20. Photochemical changes in cyanide speciation in drainage from a precious metal ore heap.

    PubMed

    Johnson, Craig A; Leinz, Reinhard W; Grimes, David J; Rye, Robert O

    2002-03-01

    In drainage from an inactive ore heap at a former gold mine, the speciation of cyanide and the concentrations of several metals were found to follow diurnal cycles. Concentrations of the hexacyanoferrate complex, iron, manganese, and ammonium were higher at night than during the day, whereas weak-acid-dissociable cyanide, silver, gold, copper, nitrite, and pH displayed the reverse behavior. The changes in cyanide speciation, iron, and trace metals can be explained by photodissociation of iron and cobalt cyanocomplexes as the solutions emerged from the heap into sunlight-exposed channels. At midday, environmentally significant concentrations of free cyanide were produced in a matter of minutes, causing trace copper, silver, and gold to be mobilized as cyanocomplexes from solids. Whether rapid photodissociation is a general phenomenon common to other sites will be important to determine in reaching a general understanding of the environmental risks posed by routine or accidental water discharges from precious metal mining facilities. PMID:11918005

  1. Photochemical changes in cyanide speciation in drainage from a precious metal ore heap

    USGS Publications Warehouse

    Johnson, C.A.; Leinz, R.W.; Grimes, D.J.; Rye, R.O.

    2002-01-01

    In drainage from an inactive ore heap at a former gold mine, the speciation of cyanide and the concentrations of several metals were found to follow diurnal cycles. Concentrations of the hexacyanoferrate complex, iron, manganese, and ammonium were higher at night than during the day, whereas weak-acid-dissociable cyanide, silver, gold, copper, nitrite, and pH displayed the reverse behavior. The changes in cyanide speciation, iron, and trace metals can be explained by photodissociation of iron and cobalt cyanocomplexes as the solutions emerged from the heap into sunlight-exposed channels. At midday, environmentally significant concentrations of free cyanide were produced in a matter of minutes, causing trace copper, silver, and gold to be mobilized as cyanocomplexes from solids. Whether rapid photodissociation is a general phenomenon common to other sites will be important to determine in reaching a general understanding of the environmental risks posed by routine or accidental water discharges from precious metal mining facilities.

  2. A Novel Designed Bioreactor for Recovering Precious Metals from Waste Printed Circuit Boards

    PubMed Central

    Jujun, Ruan; Jie, Zheng; Jian, Hu; Zhang, Jianwen

    2015-01-01

    For recovering precious metals from waste printed circuit boards (PCBs), a novel hybrid technology including physical and biological methods was developed. It consisted of crushing, corona-electrostatic separation, and bioleaching. Bioleaching process is the focus of this paper. A novel bioreactor for bioleaching was designed. Bioleaching was carried out using Pseudomonas chlororaphis. Bioleaching experiments using mixed particles of Au and Cu were performed and leachate contained 0.006 mg/L, 2823 mg/L Au+ and Cu2+ respectively. It showed when Cu existed, the concentrations of Au were extremely small. This provided the feasibility to separate Cu from Au. The method of orthogonal experimental design was employed in the simulation bioleaching experiments. Experimental results showed the optimized parameters for separating Cu from Au particles were pH 7.0, temperature 22.5 °C, and rotation speed 80 r/min. Based on the optimized parameters obtained, the bioreactor was operated for recovering mixed Au and Cu particles. 88.1 wt.% of Cu and 76.6 wt.% of Au were recovered. The paper contributed important information to recover precious metals from waste PCBs. PMID:26316021

  3. A Novel Designed Bioreactor for Recovering Precious Metals from Waste Printed Circuit Boards.

    PubMed

    Jujun, Ruan; Jie, Zheng; Jian, Hu; Zhang, Jianwen

    2015-01-01

    For recovering precious metals from waste printed circuit boards (PCBs), a novel hybrid technology including physical and biological methods was developed. It consisted of crushing, corona-electrostatic separation, and bioleaching. Bioleaching process is the focus of this paper. A novel bioreactor for bioleaching was designed. Bioleaching was carried out using Pseudomonas chlororaphis. Bioleaching experiments using mixed particles of Au and Cu were performed and leachate contained 0.006 mg/L, 2823 mg/L Au(+) and Cu(2+) respectively. It showed when Cu existed, the concentrations of Au were extremely small. This provided the feasibility to separate Cu from Au. The method of orthogonal experimental design was employed in the simulation bioleaching experiments. Experimental results showed the optimized parameters for separating Cu from Au particles were pH 7.0, temperature 22.5 °C, and rotation speed 80 r/min. Based on the optimized parameters obtained, the bioreactor was operated for recovering mixed Au and Cu particles. 88.1 wt.% of Cu and 76.6 wt.% of Au were recovered. The paper contributed important information to recover precious metals from waste PCBs. PMID:26316021

  4. Applications of multivariate analysis to precious metal exploration in the western US

    SciTech Connect

    Nelson, C.E.

    1985-01-01

    Precious metal exploration in the western United States relies heavily on geochemical analyses for so-called pathfinder elements. These are elements known to be enriched in or near ore deposits. Carlin-type ore bodies, for example, contain anomalous, but quite variable, amounts of Au, Ag, As, Sb, Hg, Tl, and Ba. Unfortunately, many Carlin-type hydrothermal systems with no associated gold ore are equally anomalous in all members of the pathfinder suite. Large geochemical databases, containing thirty to fifty elements, have been gathered for a variety of epithermal precious metal deposits in the western United States. Multivariate analysis of the data identifies new element groups, some of which are distinctive of ore-related systems. These new geochemical fingerprints are more effective than the well-known epithermal suite at establishing ore potential in untested epithermal targets. Several multivariate techniques have been applied. Discriminant analysis uses raw geochemical data to provide a function that maximizes the separation between known groups, such as ore bodies and barren systems. Factor analysis reduce the raw data to a number of geologically interpretable element groups (factors). Each of the described techniques provides tools which can be quantitatively applied to exploration.

  5. Recovery and recycling of aluminum, copper, and precious metals from dismantled weapon components

    SciTech Connect

    Lutz, J.D.; Wheelis, W.T.; Gundiler, I.H.

    1995-02-01

    Sandia National Laboratories (SNL) is tasked to support the Department of Energy in the dismantlement and disposal of SNL designed weapon components. These components are sealed in a potting compound, and contain heavy metals, explosive, radioactive, and toxic materials in discrete sub-components. SNL developed and demonstrated a process to identify and remove the hazardous sub-components utilizing real-time radiography and abrasive water-jet cutting. The remaining components were then crushed, granulated, screened, and separated into an aluminum and a precious-and-base-metals fraction using air-tables. Plastics were further cleaned for disposal as non-hazardous waste. The New Mexico Bureau of Mines & Mineral Resources assisted SNL in investigation of size-reduction and separation technologies and in the development of a conceptual design for a mechanical separation system.

  6. Recovery and recycling of aluminum, copper, and precious metals from dismantled weapon components

    SciTech Connect

    Gundiler, I.H.; Lutz, J.D.; Wheelis, W.T.

    1994-03-03

    Sandia National Laboratories (SNL) is tasked to support The Department of Energy in the dismantlement and disposal of SNL designed weapon components. These components are sealed in a potting compound, and contain heavy metals, explosive, radioactive, and toxic materials. SNL developed a process to identify and remove the hazardous sub-components utilizing real-time radiography and abrasive water-jet cutting. The components were then crushed, granulated, screened, and separated into an aluminum and a precious-and-base-metals fraction using air-tables. Plastics were further cleaned for disposal as non-hazardous waste. New Mexico Bureau of Mines and Mineral Resources assisted SNL in investigation of size-reduction and separation technologies.

  7. Durability study of transition metal based non-precious cathode in PEFC

    SciTech Connect

    Wu, Gang; Zelenay, Piotr

    2009-01-01

    This paper focuses on performance durability of newly developed polyaniline (PANI)-derived non-precious cathode catalyst, whose high oxygen-reduction activity was verified in electrochemical and fuel cell testing, exhibiting onset and half-wave potential (E{sup 1/2}) of oxygen reduction at 0.90 V and 0.77 V, respectively, as well as an insignificant H{sub 2}O{sub 2} yields below 1%. It was found catalyst durability in fuel cell life tests is greatly dependent on the catalyst synthesis including nitrogen precursors, employed transition metals, and supporting materials. Importantly, the working voltages in fuel cell testing have a profound impact on the stability, which much more stable performance can be observed at lower voltage such as 0.4 V when compared with higher voltage, 0.6 V. Preliminary physical and electrochemical characterization present to provide insight into the origin of the possible degradation mechanism for the non-precious active sites.

  8. Discriminating late volcanic differentiates commonly associated with precious metal deposits, using Landsat Thematic Mapper imagery

    NASA Technical Reports Server (NTRS)

    Spatz, David M.; Taranik, James V.

    1988-01-01

    The magmatic differentiates emplaced late in volcanotectonic cycles (which when highly evolved commonly occur as domes, flow-dome complexes, and shallow intrusive porphyries) are typically more silicic and felsic than their earlier counterparts and exhibit unusually steep spectral curves from about 1.5 to 2.2 microns. This spectral characteristic emerges in the form of relatively high Landsat TM band 7 DN values and low 5/7 values, as well as dark-contrast or enhanced 5/7 images. These evolved late-phase differentiates are commonly associated both temporally and spatially with precious metal deposits, furnishing site-specific exploration targets as well as guides to caldera margins and other late-stage volcanotectonic structures.

  9. Antimicrobial precious-metal nanoparticles and their use in novel materials.

    PubMed

    Senior, Katharina; Müller, Stefanie; Schacht, Veronika J; Bunge, Michael

    2012-12-01

    Nanotechnology offers powerful new approaches to controlling unwanted microorganisms and other potential biohazards. Engineered nanoparticles with antifungal, antimicrobial, and antiviral properties are now being developed for a variety of applications, including manufacture and maintenance of sterile surfaces, prevention and control of biological contamination, food and water safety, and treatment of infectious diseases and cancer. The great potential of antimicrobial precious-metal nanoparticles is reflected by the high number of recent publications and patent applications, which is summarized, at least in part, in this paper. This review should provide an overview and offer guidance to the scientific community interested in nano(bio)technology, nanomedicine, and nanotoxicology, and may also be of interest to a broader scientific audience. Furthermore, this review covers specific topics in research and development addressing the effects of nanoparticles on microorganisms as well as novel nanotechnology-based approaches for controlling potentially pathogenic microorganisms. PMID:23013409

  10. Structural effects of a carbon matrix in non-precious metal O2-reduction electrocatalysts.

    PubMed

    He, Wenhui; Wang, Ying; Jiang, Chunhuan; Lu, Lehui

    2016-05-01

    Developing non-precious metal electrocatalysts (NPMCs) for the oxygen reduction reaction (ORR) is of paramount importance for commercial implementation of several clean energy techniques (e.g. proton exchange membrane fuel cells). However, limited understanding of the ORR catalytic mechanism of NPMCs greatly hinders the progress in the precise fabrication of NPMCs at the molecular or atomic level. Recently, an increasing number of studies have demonstrated the crucial role of a carbon matrix in exposing, stabilizing, and activating the catalytic sites, thus providing a platform to identify the nature of NPMCs. Herein, the unique structural effects of a carbon matrix in NPMCs are first reviewed to inspire the development of more advanced NPMCs for the ORR. PMID:26955940

  11. Identification of carbon-encapsulated iron nanoparticles as active species in non-precious metal oxygen reduction catalysts

    PubMed Central

    Varnell, Jason A.; Tse, Edmund C. M.; Schulz, Charles E.; Fister, Tim T.; Haasch, Richard T.; Timoshenko, Janis; Frenkel, Anatoly I.; Gewirth, Andrew A.

    2016-01-01

    The widespread use of fuel cells is currently limited by the lack of efficient and cost-effective catalysts for the oxygen reduction reaction. Iron-based non-precious metal catalysts exhibit promising activity and stability, as an alternative to state-of-the-art platinum catalysts. However, the identity of the active species in non-precious metal catalysts remains elusive, impeding the development of new catalysts. Here we demonstrate the reversible deactivation and reactivation of an iron-based non-precious metal oxygen reduction catalyst achieved using high-temperature gas-phase chlorine and hydrogen treatments. In addition, we observe a decrease in catalyst heterogeneity following treatment with chlorine and hydrogen, using Mössbauer and X-ray absorption spectroscopy. Our study reveals that protected sites adjacent to iron nanoparticles are responsible for the observed activity and stability of the catalyst. These findings may allow for the design and synthesis of enhanced non-precious metal oxygen reduction catalysts with a higher density of active sites. PMID:27538720

  12. Identification of carbon-encapsulated iron nanoparticles as active species in non-precious metal oxygen reduction catalysts.

    PubMed

    Varnell, Jason A; Tse, Edmund C M; Schulz, Charles E; Fister, Tim T; Haasch, Richard T; Timoshenko, Janis; Frenkel, Anatoly I; Gewirth, Andrew A

    2016-01-01

    The widespread use of fuel cells is currently limited by the lack of efficient and cost-effective catalysts for the oxygen reduction reaction. Iron-based non-precious metal catalysts exhibit promising activity and stability, as an alternative to state-of-the-art platinum catalysts. However, the identity of the active species in non-precious metal catalysts remains elusive, impeding the development of new catalysts. Here we demonstrate the reversible deactivation and reactivation of an iron-based non-precious metal oxygen reduction catalyst achieved using high-temperature gas-phase chlorine and hydrogen treatments. In addition, we observe a decrease in catalyst heterogeneity following treatment with chlorine and hydrogen, using Mössbauer and X-ray absorption spectroscopy. Our study reveals that protected sites adjacent to iron nanoparticles are responsible for the observed activity and stability of the catalyst. These findings may allow for the design and synthesis of enhanced non-precious metal oxygen reduction catalysts with a higher density of active sites. PMID:27538720

  13. Distribution of Precious Metals (Ag, Au, Pd, Pt, and Rh) Between Copper Matte and Iron Silicate Slag

    NASA Astrophysics Data System (ADS)

    Avarmaa, Katri; Johto, Hannu; Taskinen, Pekka

    2016-02-01

    The distributions of precious metals (Ag, Au, Pd, Pt, and Rh) between copper matte and silica-saturated iron silicate slag were determined at 1523 K to 1623 K (1250 °C to 1350 °C), in controlled CO-CO2-SO2-Ar gas mixtures. The experiments were done in silica crucibles and a fixed partial pressure of sulfur dioxide for matte grades of 55, 65, and 75 wt pct Cu. High-temperature equilibration/quenching/electron probe X-ray microanalysis technique was used to obtain compositions of the equilibrated matte and slag. The technique was applied for the first time to the distributions of precious metals in simulated flash smelting conditions. The resolution of electron probe microanalysis became critical as the detection limits were insufficient to measure reliably the precious metals concentrations (except silver) in the slag. The distribution coefficient of silver, L m/s[Ag] = [wt pctAg in matte]/(wt pctAg in slag), was found to be between 200 and 300, which agrees well with the latest studies in the literature. For other precious metals, the minimum values of distribution coefficients were determined according to the detection limits in the slag. The values obtained were for gold and platinum >250, for palladium >1000, and for rhodium >900. The distribution coefficients of palladium, although locating above distribution coefficient of the detection limit, formed a clear dependency with a good repeatability as a function of the matte grade. It increased along with matte grade and was approximately 1000 at 50 pct Cu and 2000 to 3000 at 70 pct Cu. The precious metals replace metal in the matte structure and they are present as sulfides in the copper matte.

  14. Non-precious metal electrocatalysts with high activity for hydrogen oxidation reaction in alkaline electrolytes

    SciTech Connect

    Sheng, WC; Bivens, AP; Myint, M; Zhuang, ZB; Forest, RV; Fang, QR; Chen, JG; Yan, YS

    2014-05-01

    A ternary metallic CoNiMo catalyst is electrochemically deposited on a polycrystalline gold (Au) disk electrode using pulse voltammetry, and characterized for hydrogen oxidation reaction (HOR) activity by temperature-controlled rotating disk electrode measurements in 0.1 M potassium hydroxide (KOH). The catalyst exhibits the highest HOR activity among all non-precious metal catalysts (e.g., 20 fold higher than Ni). At a sufficient loading, the CoNiMo catalyst is expected to outperform Pt and thus provides a promising low cost pathway for alkaline or alkaline membrane fuel cells. Density functional theory (DFT) calculations and parallel H-2-temperature programmed desorption (TPD) experiments on structurally much simpler model alloy systems show a trend that CoNiMo has a hydrogen binding energy (HBE) similar to Pt and much lower than Ni, suggesting that the formation of multi-metallic bonds modifies the HBE of Ni and is likely a significant contributing factor for the enhanced HOR activity.

  15. Evidence for the formation of nitrogen-rich precious metal nanoparticles

    DOE PAGESBeta

    Veith, Gabriel M; Lupini, Andrew R; Baggetto, Loic; Browning, Jim; Keum, Jong Kahk; Villa, Alberto; Prati, Laura; Papandrew, Alexander B; Goenaga Jimenez, Gabriel A; Mullins, David R; et al

    2014-01-01

    We report evidence for the formation of nitrogen-rich precious metal nanoparticles (Pt, Pd) prepared by reactive sputtering of the pure metal in a N2 plasma. The composition of the nanoparticles varies as a function of particle size and growth conditions. For the smallest particles the nitrogen content appears to be as high as 6.7 N atoms for each Pd atom or 5.9 N atoms for each Pt atom whereas bulk films have nominal compositions of Pt7.3N and Pd2.5N. The nanoparticles are metastable in air and moisture, slowly decomposing over several years. This paper describes the synthesis of these materials alongmore » with experimental evidence of the composition, oxidation state, and growth modes. The catalytic properties of these N-rich nanoparticles were accessed by rotating disk electrode electrochemical studies, the liquid phase oxidation of benzyl alcohol and gas phase CO oxidation and support the experimental evidence for the materials composition.« less

  16. Hydrothermal precious-metal deposits related to graben-calderas of the Sierra Madre Occidental

    NASA Astrophysics Data System (ADS)

    Aguirre-Diaz, G. J.; Labarthe-Hernandez, G.; Nieto-Obregon, J.; Tristan-Gonzalez, M.; Gonzalez-Partida, E.

    2007-05-01

    The Sierra Madre Occidental (SMO) covers the NW portion of Mexico and it is the host for several important precious metal mine operations, such as Tayoltita, Cienega, Topia, Fresnillo, Zacatecas, Guanajuato and Bolaños, just to mention a few. The southern part of the Basin and Range extension affected also NW Mexico and formed NW- to NE-trending normal faults that bound many large grabens, which are particularly long and deep in the southern SMO. Both graben formation and mid-Tertiary silicic volcanic activity coincided in space and time, particularly for the 38-23 Ma period, the Ignimbrite Flare-up event, but this activity dates back to Eocene and was as young as Miocene. This volcanism included large rhyolitic domes, too. At the southern SMO, the vents of this silicic volcanism are related to graben's master faults and we have named them graben-calderas. Evidences include large pyroclastic dikes and post-ignimbrite aligned rhyolitic domes and lava dikes. All these features were found along the graben-caldera walls or on the graben's shoulders. Some of these vents are related to gold and silver hydrothermal mineralization. In most cases a paleo-lake filled the graben-caldera for a period of time, either during the ignimbrite emplacement or after it. Some of the graben-caldera ignimbrites were deposited in subaqueous environments and post-ignimbrite rhyolitic domes and dikes were intruded in non-consolidated water-saturated tuffs or sedimentary deposits. This lacustrine environment provided the necessary water for the hydrothermal system. The combination of all these factors in space and time, grabens+volcanism+water, resulted in the development of precious-metal hydrothermal ore deposits. Bolaños mine in the Bolaños graben represent our case-study, but we have confirmed the same tectono-volcanic-lake relationship at other mine-districts along the SMO. We conclude that locating the fissural vents of the silicic ignimbrites by means of just geologic mapping is be

  17. Iron Cycling in Low pH Environments - Potential Application for the Recovery of Precious Metals from Industrial Waste

    NASA Astrophysics Data System (ADS)

    Muehe, E. M.; Helle, T.; Kappler, A.

    2014-12-01

    The use of many different precious metals (gold, platinum…) and Rare Earth Elements (lanthanum, neodymium…) in the production of electronic products is drastically increasing. To meet this demand, not only mining activities but recently also the recovery of these elements from industrial waste is in the focus of research. It has been shown that the application of extracting solutions with pH values lower than 4 lead to an economically feasible recovery of industrially precious metals. This abiotic extraction efficiency can potentially be increased by using microorganisms capable of dissolving more stable minerals at low pH. In collaboration with industry, a waste incineration plant, and governmental authorities, we investigate the extraction and recovery of strategically important metals and Rare Earth Elements from industrial waste. We optimize the (bio)-geochemical conditions for the extraction of these elements. To this end, a variety of microorganisms are evaluated for efficient metal extraction. We focus on known laboratory cultures capable of oxidizing and reducing Fe minerals and S compounds. Additionally, unknown microbial communities able to increase the efficiency of precious metal extraction from the industrial waste are enriched from environments with comparable geochemical conditions found in the extraction solutions.

  18. Lead poisoning in precious metals refinery assayers: a failure to notify workers at high risk.

    PubMed

    Kern, D G

    1994-05-01

    Lead poisoning in a precious metals refinery fire assayer and a routine OSHA inspection prompted an investigation of the index facility, a survey of the industry, and efforts to notify assayers of this previously unrecognized hazard. Air and blood samples were obtained at the index facility. Management personnel from all fire assay laboratories in Rhode Island and southern Massachusetts were interviewed. The industry's trade association, OSHA, NIOSH, trade unions, and the media were asked to assist in a nationwide notification effort. Assayers at the index facility had excessive exposures to lead due to an age-old, lead-based assaying method that remains the industry gold standard. Blood lead levels of the three assayers (mean 61.3 micrograms/dl, range 48-86 micrograms/dl) were considerably higher than those of 16 other refinery workers (mean 27.4 micrograms/dl, range 13-49 micrograms/dl). The industry survey revealed inadequate knowledge of both the lead hazard and the applicability of the OSHA lead standard. Notification efforts failed in large part due to economic obstacles. The notification of workers at high risk of lead exposure and the eradication of occupational lead poisoning will require greater attention to economic forces. PMID:8030646

  19. The nuclear analytical method in historical science: The case of precious metals from the New World

    SciTech Connect

    Barrandon, J.N.

    1994-01-01

    As in all the other areas of science, the nuclear method of analysis was brought about at the end of the 1940s new tools of research in the studies of man and his environment. If the applications of these methods are well-known in the field of archeology and of numismatics, it is an area where their use are more surprising, it is this that of economic history. The authors would like to illustrate this type of application using two examples: the diffusion in Europe of Potosian silver during the 16th and 17th centuries and also of Brazilian gold in 18th century. Until the 19th century most money was in the form of coinage and monetary history was mainly determined by the inflow of precious metals and the discoveries of new sources, especially in the Americas. Californian gold in the mid 19th century, Brazilian gold in the 18th and silver from Potosi or Mexico in the 16th and 18th centuries all strongly influenced the movement of price levels and European economic development. In these two cases the use of the activation methods developed around a cyclotron proved determinate.

  20. Autothermal reforming of dimethyl ether with CGO-based precious metal catalysts

    NASA Astrophysics Data System (ADS)

    Choi, Seunghyeon; Bae, Joongmyeon

    2016-03-01

    In this paper, we investigated the DME ATR reaction with different types of precious metal (Pt, Rh, Ru)-supported CGO catalysts. We also evaluated the reaction characteristics of DME ATR reaction by modifying certain reforming conditions, including the temperature, the amount of air and water, and the flow rate. The Ru-added CGO catalyst showed the best performance in DME ATR. The operating condition that produced the greatest effect on conversion efficiency was temperature; however the amounts of steam and air were also important with regard to conversion efficiency and the reaction heat. In case higher GHSV conditions the methane yields are increased. To maximize conversion efficiency with thermal neutral operating conditions, we suggest an SCR of 1.5, OCR of 0.45, over temperature of 700 °C, and a GHSV of less than 20,000/h. Under harsh conditions, such as low temperature and high GHSV, the methane yield increases. Therefore, the high temperature DME ATR reaction seems to consist of two main steps: the DME decomposition to methane and the methane autothermal reforming reaction.

  1. Characterization of Continuous and Discontinuous Precipitation Phases in Pd-Rich Precious Metal Alloys

    NASA Astrophysics Data System (ADS)

    Susan, Donald F.; Ghanbari, Zahra; Kotula, Paul G.; Michael, Joseph R.; Rodriguez, Mark A.

    2014-08-01

    Aberration-corrected scanning transmission electron microscopy (AC-STEM), X-ray diffraction (XRD), electron backscatter diffraction, and electron probe microanalysis were applied to characterize continuous and discontinuous phase formation in precious metal alloys used in electrical contacts. The Pd-rich Paliney® (®Paliney is tradename of Deringer-Ney Inc., Bloomfield, CT) alloys contain Pd, Ag, Cu, Au, Pt (and Zn or Ni). With aging at 755 K (482 °C), nanometer-scale chemistry modulation was observed indicating spinodal decomposition. An ordered body-centered tetragonal (bct) structure was also observed with AC-STEM after the 755 K (482 °C) aging treatment and another phase, tentatively identified as β-Cu3Pd4Zn, was found by microscopy and XRD after prolonged holds at higher temperatures. During slow cooling or isothermal holds at high temperature [755 K to 973 K (482 °C to 700 °C)], a two-phase lamellar structure develops along grain boundaries by discontinuous precipitation. XRD and AC-STEM showed that the lamellar structure was comprised of Ag-rich and Cu-rich fcc phases ( α 1 and α 2). The phases are discussed in relation to a pseudo-ternary diagram based on Ag-Cu-Pd, which provides a simplified representation of the discontinuous phase compositions in the multi-component alloy system.

  2. Recovery of Rare Earths, Precious Metals and Other Critical Materials from Geothermal Waters with Advanced Sorbent Structures

    SciTech Connect

    Pamela M. Kinsey

    2015-09-30

    The work evaluates, develops and demonstrates flexible, scalable mineral extraction technology for geothermal brines based upon solid phase sorbent materials with a specific focus upon rare earth elements (REEs). The selected organic and inorganic sorbent materials demonstrated high performance for collection of trace REEs, precious and valuable metals. The nanostructured materials typically performed better than commercially available sorbents. Data contains organic and inorganic sorbent removal efficiency, Sharkey Hot Springs (Idaho) water chemsitry analysis, and rare earth removal efficiency from select sorbents.

  3. Hydrothermal speleogenesis in the Eastern Basin and Range Province - Implications for Petroleum and precious-metal exploration

    SciTech Connect

    Green, D.J.; Hulen, J.B. )

    1993-08-01

    Previous investigations based on geometric and textural and analysis have shown that most caverns in the eastern Basin and Range province were excavated not by cool, descending, meteoric waters at or above the water table, but by ascending, moderate-temperature hydrothermal fluids. This conclusion, borne out by fluid-inclusion studies, has important implications for both petroleum and precious-metal exploration in the region. Cavernous porosity has been reported in some of the area's carbonate-hosted oil reservoirs, such as the geothermally active Grant Canyon field in Railroad Valley, as well as in massive carbonates directly beneath some Carlin-type, sediment-hosted gold deposits. Moreover, at virtually all such deposits, hydrothermal carbonate-dissolution (Decalcifcation) is known to be an important porosity-inducing process. Rather than being accidental components of these oil and gold occurrences, the authors contend that such caverns may have formed in the same hydrothermal systems ultimately responsible for petroleum entrapment and precious-metal ultimately responsible for petroleum entrapment and precious-metal mineralization. The fluids that excavated the caverns must have been at least mildly acidic. Carbonic acid is the traditionally cited cavern solvent, but organic and sulfur-based acids thermally generated from regionally prevalent hydrocarbon source rocks, such as the Mississippian Chainman Shale, are equally likely as agents of dissolution. The authors suggest that thermal waters charged with these acids locally may have created or enhanced not only caverns, but migration pathways and depositional sites for gold and oil alike.

  4. The acanthocephalan Paratenuisentis ambiguus as a sensitive indicator of the precious metals Pt and Rh from automobile catalytic converters.

    PubMed

    Sures, B; Zimmermann, S; Sonntag, C; Stüben, D; Taraschewski, H

    2003-01-01

    Recent studies revealed that intestinal acanthocephalans of fish can accumulate heavy metals to concentrations orders of magnitude higher than those in the host tissues or the aquatic environment. This significant heavy metal accumulation by acanthocephalans, even surpassing that of established free living accumulation bioindicators, encouraged us to study the bioavailability of the platinum-group-metals (PGM) Pt and Rh for parasites. These precious metals are used in catalytic converters of cars for exhaust gas purification in Europe since the early 1980s. In addition to the beneficial effect in reducing the emission of CHx, CO and NOx of cars there is an increasing emission of these metals. However, it still remains unclear if these elements become accumulated in the biosphere and whether they affect the health of organisms. The present study reveals that in European eels (Anguilla anguilla) naturally infected with the eoacanthocephalan parasite Paratenuisentis ambiguus and experimentally exposed to ground catalytic converter material, the parasites take up and accumulate the catalytic active metals Pt and Rh whereas in the examined host tissues we found no metal uptake. Compared with the PGM concentrations in the water the worms contained 1600 times higher Rh and 50 times higher Pt concentrations. Thus, the parasites can be used as sentinel organisms reflecting even very low levels of precious metals. PMID:12547529

  5. Non-precious metal catalysis for proton-exchange membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Leonard, Nathaniel Dean

    Non-precious metal catalysts (NPMC) for proton exchange membrane fuel cells (PEMFC) are explored. Research into NPMCs is motivated by the growing need for cleaner, more efficient energy options. NPMCs are one option to make fuel cells more commercially viable. To this end, the present work studies and simulates the morphology and function of metal-nitrogen-carbon (MNC) oxygen reduction catalysts. A porosity study finds that mesoporosity is critical to high performance of autogenic pressure metal-nitrogen-carbon (APMNC) oxygen reduction catalysts. Various carbon materials are used as precursors to synthesis APMNC catalysts. The catalysts and the associated porous carbon materials are characterized morphologically, chemically, and electrochemically. The results indicated that substrates adsorbing the most nitrogen and iron show the highest activity. Furthermore, a relationship is found between mesoporosity and nitrogen content indicating the importance of transport to active site creation. A correlation is found between surface alkalinity and catalytic activity for APMNC catalysts. The basic site strength and quantity were calculated by two different methods, and it was shown that increased Bronsted- Lowry basicity correlates to more active catalysts. The relationship between alkalinity and catalytic activity could be the result of the impact of alkalinity on the electron density of the metal centers or basic sites could encourage active site formation. It is found that the oxygen reduction reaction (ORR) proceeds both via a direct four-electron pathway to water at high potentials and an indirect peroxide pathway at low potentials on an APMNC catalyst. At higher potential, site availability inhibits peroxide generation causing the direct four-electron reduction pathway to dominate. Oxygen reduction begins to shift to the indirect peroxide pathway due to fast kinetics and higher site availability around 0.6 V vs RHE. The net peroxide generation remains relatively low

  6. Precious metals and rare earth elements in municipal solid waste--sources and fate in a Swiss incineration plant.

    PubMed

    Morf, Leo S; Gloor, Rolf; Haag, Olaf; Haupt, Melanie; Skutan, Stefan; Di Lorenzo, Fabian; Böni, Daniel

    2013-03-01

    In Switzerland many kinds of waste, e.g. paper, metals, electrical and electronic equipment are separately collected and recycled to a large extent. The residual amount of municipal solid waste (MSW) has to be thermally treated before final disposal. Efforts to recover valuable metals from incineration residues have recently increased. However, the resource potential of critical elements in the waste input (sources) and their partitioning into recyclable fractions and residues (fate) is unknown. Therefore, a substance flow analysis (SFA) for 31 elements including precious metals (Au, Ag), platinum metal group elements (Pt, Rh) and rare earth elements (La, Ce, etc.) has been conducted in a solid waste incinerator (SWI) with a state-of-the-art bottom ash treatment according to the Thermo-Re® concept. The SFA allowed the determination of the element partitioning in the SWI, as well as the elemental composition of the MSW by indirect analysis. The results show that the waste-input contains substantial quantities of precious metals, such as 0.4 ± 0.2mg/kg Au and 5.3 ± 0.7 mg/kg Ag. Many of the valuable substances, such as Au and Ag are enriched in specific outputs (e.g. non-ferrous metal fractions) and are therefore recoverable. As the precious metal content in MSW is expected to rise due to its increasing application in complex consumer products, the results of this study are essential for the improvement of resource recovery in the Thermo-Re® process. PMID:23085306

  7. Precious metal-bearing epithermal deposits in western Patagonia (NE Lago Fontana region), Argentina

    NASA Astrophysics Data System (ADS)

    Lanfranchini, Mabel Elena; Etcheverry, Ricardo Oscar; de Barrio, Raúl Ernesto; Recio Hernández, Clemente

    2013-04-01

    Precious metal-bearing quartz veins occur at the northeastern sector of the Lago Fontana region in southwestern Argentina, within the context of the Andean continental magmatic arc environment. The deposits and their associated alteration zones are spatially related to a Cretaceous calc-alkaline magmatism represented by silicic dikes and hypabyssal intrusions, and hosted by a Late Jurassic to Cretaceous volcano-sedimentary sequence. The veins and related veinlets crop out discontinuously, in general terms in a NW-SE belt. The primary vein mineral assemblage is composed mostly of pyrite ± galena ± chalcopyrite > hematite ± arsenopyrite in silica gangue minerals. Chemical analyses of grab samples from selected quartz veins show as much as 5.7 ppm Au and 224 ppm Ag, as well as elevated Pb, Cu, and Zn. Hydrothermal fluids caused an innermost silicification and adularia-sericite alteration assemblage, and an external propylitic halo. Sulfur isotope values measured for sulfides (δSS from -1.90 to +1.56‰), and oxygen and hydrogen isotopes measured on quartz crystals and extracted primary fluid inclusion waters (δOO = -2.85 to +5.40‰; δDO = -106.0 to -103.4‰) indicate that mineralization probably formed from magmatic fluids, which were mixed with meteoric waters. Also, fluid inclusion data from quartz veins point out that these fluids had low salinity (1.7-4.2 wt% NaCl equiv.), and temperatures of homogenization between 180 and 325 °C. Mineralogical, petrographic and geochemical features for mineralized surface exposures indicate a typical adularia-sericite, low sulfidation epithermal system in the Lago Fontana area that represents a promising target for further exploration programs.

  8. Discrimination of precious/base metal mineralising systems by fractal analysis, Mt Isa, Australia

    NASA Astrophysics Data System (ADS)

    Blenkinsop, T.; Oliver, N.

    2003-04-01

    Fractal analysis of deposit and prospect distribution provides a new and valuable tool in interpreting mineralisation patterns and developing exploration strategies, as demonstrated here for the Mount Isa block in Queensland, Australia. The district is one of the world’s most richly endowed base metal provinces; it also has significant precious metal deposits. Genetic models for the base metal deposits have included syngenetic and epigenetic extremes. The comprehensive data base in the North West Queensland Mineral Province Report is used to analyse copper (n=1867), copper-gold (n=211), gold (n=80), zinc-lead-silver (n=186) and uranium (n=212) mineral occurrences, prospects, existing and abandoned mines. Spatial distributions are analysed by counting the number of boxes (N[r]) of size r containing one or more localities as a function of r. Spectacularly different relationships between N[r] and r are observed for the different metals. In all cases, the trend of N[r] with r becomes almost flat at values of r on the order of hundreds of metres. This ``roll-off" effect may be due to lack of discovery of deposits. Relationships between N[r] and r at the largest box sizes may be influenced by a truncation effect. Approximate fractal dimensions (D) of the spatial distribution of each deposit type were evaluated avoiding both roll-off and truncation. The most clustered distributions were observed for Au (D ˜0.29) followed by Zn-Pb-Ag (D ˜0.41), U (D ˜0.87), Cu-Au (D ˜0.93) and Cu (D ˜1.3). This implies that there are strong differences between the mineralising systems of Au and Cu, and that neither Cu nor Au is clearly related to the family of Cu-Au deposits in the district. Au mineralization is highly clustered, implying localisation of mineralising fluid flow. In contrast, the Cu pattern indicates a more pervasive mineralising system. The latter is compatible with popular models which suggest that fluid mixing led to copper deposition, and that both metal source

  9. High pressure pyrolyzed non-precious metal oxygen reduction catalysts for alkaline polymer electrolyte membrane fuel cells.

    PubMed

    Sanetuntikul, Jakkid; Shanmugam, Sangaraju

    2015-05-01

    Non-precious metal catalysts, such as metal-coordinated to nitrogen doped-carbon, have shown reasonable oxygen reduction reaction (ORR) performances in alkaline fuel cells. In this report, we present the development of a highly active, stable and low-cost non-precious metal ORR catalyst by direct synthesis under autogenic-pressure conditions. Transmission electron microscopy studies show highly porous Fe-N-C and Co-N-C structures, which were further confirmed by Brunauer-Emmett-Teller surface area measurements. The surface areas of the Fe-N-C and Co-N-C catalysts were found to be 377.5 and 369.3 m(2) g(-1), respectively. XPS results show the possible existence of N-C and M-Nx structures, which are generally proposed to be the active sites in non-precious metal catalysts. The Fe-N-C electrocatalyst exhibits an ORR half-wave potential 20 mV higher than the reference Pt/C catalyst. The cycling durability test for Fe-N-C over 5000 cycles shows that the half-wave potential lost only 4 mV, whereas the half-wave potential of the Pt/C catalyst lost about 50 mV. The Fe-N-C catalyst exhibited an improved activity and stability compared to the reference Pt/C catalyst and it possesses a direct 4-electron transfer pathway for the ORR process. Further, the Fe-N-C catalyst produces extremely low HO2(-) content, as confirmed by the rotating ring-disk electrode measurements. In the alkaline fuel single cell tests, maximum power densities of 75 and 80 mW cm(-2) were observed for the Fe-N-C and Pt/C cathodes, respectively. Durability studies (100 h) showed that decay of the fuel cell current was more prominent for the Pt/C cathode catalyst compared to the Fe-N-C cathode catalyst. Therefore, the Fe-N-C catalyst appears to be a promising new class of non-precious metal catalysts prepared by an autogenic synthetic method. PMID:25833146

  10. Precious-metal deposits in relation to volcanic and sedimentary stratigraphy: Examples from the Oregon Plateau, U. S. A

    SciTech Connect

    Cummings, M.L. )

    1990-06-01

    Miocene to Recent volcanic and sedimentary rocks of the Oregon Plateau host precious-metal deposits. The deposits, formed within an extensional tectonic setting, illustrate the relation among volcanic and sedimentary stratigraphy, regional structural development, and hydrothermal systems. Gold deposits hosted in felsic volcaniclastic sediments in the Owyhee region formed during or shortly after sedimentation. Uniformly silicified tuffaceous mudstone and siltstone interbedded with siliceous and sulfide-rich sediments and bedded hydrathermal breccia, hydrothermal explosion craters infilled by breccia fragments, and stacked buried sinter deposits attest to mineralization near the time of sedimentation. The regional structures that controlled the distribution of volcanic activity and location of sedimentary basins changed through time. In the middle Miocene, basin-and range faults controlled the location of basalt and rhyolitic volcanism and fluvial and lacustrine basins. In the late Miocene and Pliocene, faults parallel to those of the Western Snake River Plain are more prominent and interfingering volcanic and volcaniclastic sedimentary deposits characterize the stratigraphic section. Fault-controlled mercury mineralization in quartz within opalized high-silica rhyolite flow-domes produces an obscure precious-metal prospect at Glass Buttes in the High Lava Plains. Glassy high-silica rhyolite flow-domes were erupted between 5.8 and 5.0 ma but alteration and mineralization occur along faults of the Brothers fault zone that cut the high-silica rhyolite sequence. Younger porphyritic rhyolite to dacite domes, spines, and intrusions controlled by faults of the Brothers fault zone are believed to be the heat source for the hydrothermal system. Precious-metal mineralization may occur in the subsurface where hydrothermal solutions boiled beneath the paleowater table.

  11. Age and genesis of precious metals deposits, Buffalo Hump district, central Idaho: implications for depth of emplacement of quartz veins.

    USGS Publications Warehouse

    Lund, K.; Snee, L.W.; Evans, K.V.

    1986-01-01

    Three samples (metamorphic country rock, Idaho batholith granite, and auriferous quartz vein) were dated by the 40Ar/39Ar age spectrum technique. The lode deposits are Cretaceous (71 m.y.); their cooling histories and depths of emplacement, inferred from the age spectra, are evidence for the granite plutons and the lode deposits having been emplaced at the same 40-9 km depth and being genetically related. Thus, the Idaho batholith is not barren, and at least two precious-metal mineralizing events, Cretaceous and Eocene in age, occur in central Idaho. Class differences between the two ages of deposits, of style, alteration and mineralogy, are suggested. -G.J.N.

  12. Geologic and grade-tonnage information on Tertiary epithermal precious- and base-metal vein districts associated with volcanic rocks

    USGS Publications Warehouse

    Mosier, Dan L.; Menzie, W. David; Kleinhampl, Frank J.

    1986-01-01

    Data on grades, tonnages, and geology of selected Tertiary epithermal precious- and base-metal vein districts associated with volcanic rocks were tabulated for ease of examination and comparison of characteristics between districts. There are 215 districts listed, with a cumulative tonnage of 709 million metric tons and average grades of 4.7 g/t Au, 224 g/t Ag, 0.16 percent Cu, 0.55 percent Pb, and 0.83 percent Zn, representing about 60 percent of world districts.

  13. Precious metals and rare earth elements in municipal solid waste – Sources and fate in a Swiss incineration plant

    SciTech Connect

    Morf, Leo S.; Gloor, Rolf; Haag, Olaf; Haupt, Melanie; Skutan, Stefan; Lorenzo, Fabian Di; Böni, Daniel

    2013-03-15

    Highlights: ► We carefully addressed all the very valuable comments and suggestions of the reviewers. ► We also have shortened the size of the paper and tried simplify it substantially, as requested by the reviewers (introduction 25% reduced!). ► We have decided to take the chance and have replaced the data for the “additional” elements (Cu, Cd, Zn, Pb, Sn, Cr, Ni, Fe, Al) of the earlier MFA (Morf, 2011) with data that belong to the samples of this study. ► We are convinced that with the revision the paper has significantly improved in quality and attractiveness. - Abstract: In Switzerland many kinds of waste, e.g. paper, metals, electrical and electronic equipment are separately collected and recycled to a large extent. The residual amount of municipal solid waste (MSW) has to be thermally treated before final disposal. Efforts to recover valuable metals from incineration residues have recently increased. However, the resource potential of critical elements in the waste input (sources) and their partitioning into recyclable fractions and residues (fate) is unknown. Therefore, a substance flow analysis (SFA) for 31 elements including precious metals (Au, Ag), platinum metal group elements (Pt, Rh) and rare earth elements (La, Ce, etc.) has been conducted in a solid waste incinerator (SWI) with a state-of-the-art bottom ash treatment according to the Thermo-Re® concept. The SFA allowed the determination of the element partitioning in the SWI, as well as the elemental composition of the MSW by indirect analysis. The results show that the waste-input contains substantial quantities of precious metals, such as 0.4 ± 0.2 mg/kg Au and 5.3 ± 0.7 mg/kg Ag. Many of the valuable substances, such as Au and Ag are enriched in specific outputs (e.g. non-ferrous metal fractions) and are therefore recoverable. As the precious metal content in MSW is expected to rise due to its increasing application in complex consumer products, the results of this study are

  14. Precious metal recovery from waste printed circuit boards using cyanide and non-cyanide lixiviants--A review.

    PubMed

    Akcil, Ata; Erust, Ceren; Gahan, Chandra Sekhar; Ozgun, Mehmet; Sahin, Merve; Tuncuk, Aysenur

    2015-11-01

    Waste generated by the electrical and electronic devices is huge concern worldwide. With decreasing life cycle of most electronic devices and unavailability of the suitable recycling technologies it is expected to have huge electronic and electrical wastes to be generated in the coming years. The environmental threats caused by the disposal and incineration of electronic waste starting from the atmosphere to the aquatic and terrestrial living system have raised high alerts and concerns on the gases produced (dioxins, furans, polybrominated organic pollutants, and polycyclic aromatic hydrocarbons) by thermal treatments and can cause serious health problems if the flue gas cleaning systems are not developed and implemented. Apart from that there can be also dissolution of heavy metals released to the ground water from the landfill sites. As all these electronic and electrical waste do posses richness in the metal values it would be worth recovering the metal content and protect the environmental from the pollution. Cyanide leaching has been a successful technology worldwide for the recovery of precious metals (especially Au and Ag) from ores/concentrates/waste materials. Nevertheless, cyanide is always preferred over others because of its potential to deliver high recovery with a cheaper cost. Cyanidation process also increases the additional work of effluent treatment prior to disposal. Several non-cyanide leaching processes have been developed considering toxic nature and handling problems of cyanide with non-toxic lixiviants such as thiourea, thiosulphate, aqua regia and iodine. Therefore, several recycling technologies have been developed using cyanide or non-cyanide leaching methods to recover precious and valuable metals. PMID:25704926

  15. A new approach to precious metals recovery from brown coals: Correlation of recovery efficacy with the mechanism of metal-humic interactions

    NASA Astrophysics Data System (ADS)

    Bratskaya, Svetlana Yu.; Volk, Alexandra S.; Ivanov, Vladimir V.; Ustinov, Alexander Yu.; Barinov, Nikolay N.; Avramenko, Valentin A.

    2009-06-01

    The presence of gold and platinum group elements (PGE) in low-rank brown coals around the world has promoted interest in the industrial exploitation of this alternative source of precious metals. However, due to low efficacy of the methods traditionally used for the processing of mineral ores, there exists a high demand for new strategies of precious metal recovery from refractory carbonaceous materials that could significantly increase the economic potential of gold- and PGE-bearing organic resources. Here we discuss the possibility of gold and PGE recovery from alkaline extracts of brown coals using the difference in colloidal stability of bulk organic matter and its fractions enriched with precious metals. This approach enables one to avoid complete oxidation or combustion of brown coals prior to gold recovery, to minimize organic content in gold concentrate, and to obtain a valuable by-product - humic extracts. Using gold-bearing brown coals from several deposits located in the South Far East of Russia, we show that up to 95% of gold can be transferred to alkaline extracts of humic acids (HA) and up to 85% of this gold can be recovered by centrifugation at pH 4.0-6.0, when only 5-15% of HA precipitated simultaneously. We have shown that the high efficacy of gold recovery can be attributed to the occurrence of fine-dispersed elemental gold particles stabilized by HA, which differ significantly in colloidal stability from the bulk organic matter and, thus, can be separated by centrifugation.

  16. Self-assembly synthesis of precious-metal-free 3D ZnO nano/micro spheres with excellent photocatalytic hydrogen production from solar water splitting

    NASA Astrophysics Data System (ADS)

    Guo, Si-yao; Zhao, Tie-jun; Jin, Zu-quan; Wan, Xiao-mei; Wang, Peng-gang; Shang, Jun; Han, Song

    2015-10-01

    A simple and straightforward solution growth routine is developed to prepare microporous 3D nano/micro ZnO microsphere with a large BET surface area of 288 m2 g-1 at room temperature. The formation mechanism of the hierarchical 3D nano/micro ZnO microsphere and its corresponding hydrogen evolution performance has been deeply discussed. In particular, this novel hierarchical 3D ZnO microspheres performs undiminished hydrogen evolution for at least 24 h under simulated solar light illumination, even under the condition of no precious metal as cocatalyst. Since the complex production process of photocatalysts and high cost of precious metal cocatalyst remains a major constraint that hinders the application of solar water splitting, this 3D nano/micro ZnO microspheres could be expected to be applicable in the precious-metal-free solar water splitting system due to its merits of low cost, simple procedure and high catalytic activity.

  17. Bioreduction of Precious Metals by Microorganism: Efficient Gold@N-Doped Carbon Electrocatalysts for the Hydrogen Evolution Reaction.

    PubMed

    Zhou, Weijia; Xiong, Tanli; Shi, Chaohong; Zhou, Jian; Zhou, Kai; Zhu, Nengwu; Li, Ligui; Tang, Zhenghua; Chen, Shaowei

    2016-07-11

    The uptake of precious metals from electronic waste is of environmental significance and potential commercial value. A facile bioreductive synthesis is described for Au nanoparticles (ca. 20 nm) supported on N-doped carbon (Au@NC), which was derived from Au/Pycnoporus sanguineus cells. The interface and charge transport between Au and N-doped carbon were confirmed by HRTEM and XPS. Au@NC was employed as an electrocatalyst for the hydrogen evolution reaction (HER), exhibiting a small onset potential of -54.1 mV (vs. RHE), a Tafel slope of 76.8 mV dec(-1) , as well as robust stability in acidic medium. Au@NC is a multifunctional electrocatalyst, which demonstrates high catalytic activity in the oxygen reduction reaction (ORR), as evidenced by an onset potential of +0.97 V, excellent tolerance toward methanol, and long-term stability. This work exemplifies dual recovery of precious Au and fabrication of multifunctional electrocatalysts in an environmentally benign and application-oriented manner. PMID:27218302

  18. Nuclear fuel and precious-metal occurrences in Precambrian rocks of southeast Wyoming

    SciTech Connect

    Graff, P.

    1986-08-01

    Studies done on Precambrian metasediments in southeast Wyoming show the occurrence of quartz-pebble conglomerates containing subeconomic amounts of uranium and thorium. These conglomerates were marginal deposits in the late 1970s when uranium prices reached $50/lb. Fuel minerals occur in silicate phases and complicate milling operations. Because of the additional cost of processing and underground mining, no attempt to develop these resources was made. Additional studies show a favorable comparison of the rocks in Wyoming to the auriferous Witwatersrand section of South Africa. Exploration for gold in the Wyoming conglomerates has been done in a preliminary manner, but assay values to 10 ppm are reported. Both fuel minerals and gold are deposited as fossil placers by fluvial systems operating in an anoxic environment. Lag gravel and meander deposits contain heavy-mineral suites formed of coffinite, pyrite, thorite, gold, and uraninite. Available studies have not considered producing fuel and precious minerals as coproducts of surface mining methods.

  19. Manganese Oxide Nanorod-Decorated Mesoporous ZSM-5 Composite as a Precious-Metal-Free Electrode Catalyst for Oxygen Reduction.

    PubMed

    Cui, Xiangzhi; Hua, Zile; Chen, Lisong; Zhang, Xiaohua; Chen, Hangrong; Shi, Jianlin

    2016-05-10

    A precious-metal-free cathode catalyst, MnO2 nanorod-decorated mesoporous ZSM-5 zeolite nanocomposite (MnO2 / m-ZSM-5), has been successfully synthesized by a hydrothermal and electrostatic interaction approach for efficient electrochemical catalysis of the oxygen reduction reaction (ORR). The active MnOOH species, that is, Mn(4+) /Mn(3+) redox couple and Brønsted acid sites on the mesoporous ZSM-5 matrix facilitate an approximately 4 e(-) process for the catalysis of the ORR comparable to commercial 20 wt % Pt/C. Stable electrocatalytic activity with 90 % current retention after 5000 cycles, and more importantly, excellent methanol tolerance is observed. Synergetic catalytic effects between the MnO2 nanorods and the mesoporous ZSM-5 matrix are proposed to account for the high electrochemical catalytic performance. PMID:27038172

  20. Oxidation of Aliphatic Alcohols by Using Precious Metals Supported on Hydrotalcite under Solvent- and Base-Free Conditions.

    PubMed

    He, Yufei; Feng, Junting; Brett, Gemma L; Liu, Yanan; Miedziak, Peter J; Edwards, Jennifer K; Knight, David W; Li, Dianqing; Hutchings, Graham J

    2015-10-12

    Precious metal nanoparticles supported on magnesium-aluminum hydrotalcite (HT), TiO2 , and MgO were prepared by sol immobilization and assessed for the catalytic oxidation of octanol, which is a relatively unreactive aliphatic alcohol, with molecular oxygen as the oxidant under solvent- and base-free conditions. Compared with the TiO2 - and MgO-supported catalysts, platinum HT gave the highest activity and selectivity towards the aldehyde. The turnover number achieved for the platinum HT catalyst was >3700 after 180 min under mild reaction conditions. Moreover, the results for the oxidation of different substrates indicate that a specific interaction of octanal with the platinum HT catalyst could lead to deactivation of the catalyst. PMID:26337897

  1. Treatment of copper ores and concentrates with industrial nitrogen species catalyzed pressure leaching and non-cyanide precious metals recovery

    NASA Astrophysics Data System (ADS)

    Anderson, Corby G.

    2003-04-01

    Today, with a stringent economic and environmental climate prevailing in the copper business, there is increased interest in evaluating new processing alternatives for production. Hydrometallurgical pressure oxidation of copper concentrates is one of the more viable approaches, and several technological candidates have emerged. Of these, an overlooked but, ironically, the first industrially proven methodology utilized nitrogen species catalyzation in the oxidizing pressure-leach system to produce copper via solvent extraction/electrowinning. Given its advantages, this may prove to be a feasible process alternative for the future. In this article, the history of the system and its application to copper concentrates and ores will be outlined. In particular, a non-cyanide methodology for effective recovery of precious metals from chalcopyrite concentrates will be discussed.

  2. Rapid Computer Aided Ligand Design and Screening of Precious Metal Extractants from TRUEX Raffinate with Experimental Validation

    SciTech Connect

    Clark, Aurora Sue; Wall, Nathalie; Benny, Paul

    2015-11-16

    Rhodium is the most extensively used metal in catalytic applications; it occurs in mixed ores with platinum group metals (PGMs) in the earth’s crust in low concentrations (0.4 - 10 ppb). It is resistant to aerial oxidation and insoluble in all acids, including aqua regia, making classical purification methods time-consuming and inefficient. To ensure adequate purity, several precipitation and dissolution steps are necessary during separation. Low abundance, high demand, and extensive processing make rhodium the most expensive of all PGMs. From alternative sources, rhodium is also produced in sufficient quantities (0.47 kg per ton initial heavy metal (tIHM)) during the fission of U-235 in nuclear reactors along with other PGMs (i.e., Ag, Pd, Ru). A typical power water reactor operating with UO2 fuel after cooling can generate PGMs in quantities greater than found in the earth’s crust (0.5-2 kg/tIHM). This currently untapped supply of PGMs has the potential to yield $5,000-30,000/tIHM. It is estimated that by the year 2030, the amount of rhodium generated in reactors could exceed natural reserves. Typical SNF processing removes the heavier lanthanides and actinides and can leave PGMs at ambient temperatures in aqueous acidic (Cl⁻ or NO3⁻; pH < 1) solutions at various activities. While the retrieval of these precious metals from SNF would minimize waste generation and improve resource utilization, it has been difficult to achieve thus far. Two general strategies have been utilized to extract Rh(III) from chloride media: ion pairing and coordination complexation. Ion pairing mechanisms have been studied primarily with the tertiary and quaternary amines. Additionally, mixed mechanism extractions have been observed in which ion pairing is the initial mechanism, and longer extraction equilibrium time generated coordination complexes. Very few coordination complexation extraction ligands have been studied. This project approached this problem

  3. One-pot synthesis of high-performance Co/graphene electrocatalysts for glucose fuel cells free of enzymes and precious metals.

    PubMed

    Ci, Suqin; Wen, Zhenhai; Mao, Shun; Hou, Yang; Cui, Shumao; He, Zhen; Chen, Junhong

    2015-06-01

    A facile recipe has been developed to prepare three-dimensional nanoarchitectures of nitrogen-doped graphene loading Co nanoparticle hybrids (Co/NG). The hybrids show an outstanding electrocatalytic activity for glucose oxidation reaction (GOR) and oxygen reduction reaction (ORR), and thus can be used as electrode materials of a nonenzymatic and precious-metal-free glucose fuel cell (GFC). PMID:25960100

  4. Electronic properties of precious-metal coated W tips in STM: Role of spin-orbit coupling

    NASA Astrophysics Data System (ADS)

    Yamashita, T.; Akiyama, T.; Nakamura, K.; Ito, T.; Rhim, S. H.; Freeman, A. J.

    2013-03-01

    Scanning tunneling microscopy (STM) has proved a versatile tool invigorating many physics at an atomic scale, where chemical identity and shape of the probe tip greatly affect resolution and sensitivity. There have been many efforts to functionalize STM tips: coating W tips with organic molecules and 3d transition metals, which facilitate the selective imaging with enhanced tunneling current. In this work, we model W(110) tips coated by precious metals such as Au, Ag, and Pt, in which large spin-orbit coupling significantly influences the electronic structure of the STM probe. Furthermore, we argue that this spin-orbit coupling can be used as a spin detecting STM probe without additional bias switching. The stability of the W(110) apex atom for each metal coating is also discussed. Supported at N. U. by the DOE (DE-FG02-05ER45372), and at Mie U. by the Young Researcher Overseas Visits Program for Vitalizing Brain Circulation (R2214) from the Japan Society for the Promotion of Science.

  5. 48 CFR 252.208-7000 - Intent to furnish precious metals as Government-furnished material.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Offeror shall cite the type (silver, gold, platinum, palladium, iridium, rhodium, and ruthenium) and... metal* Quantity Deliverable item (NSN and nomenclature)!!rs *If platinum or palladium, specify...

  6. 48 CFR 252.208-7000 - Intent to furnish precious metals as Government-furnished material.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Offeror shall cite the type (silver, gold, platinum, palladium, iridium, rhodium, and ruthenium) and... metal* Quantity Deliverable item (NSN and nomenclature)!!rs *If platinum or palladium, specify...

  7. 48 CFR 252.208-7000 - Intent to furnish precious metals as Government-furnished material.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Offeror shall cite the type (silver, gold, platinum, palladium, iridium, rhodium, and ruthenium) and... metal* Quantity Deliverable item (NSN and nomenclature)!!rs *If platinum or palladium, specify...

  8. 48 CFR 252.208-7000 - Intent to furnish precious metals as Government-furnished material.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Offeror shall cite the type (silver, gold, platinum, palladium, iridium, rhodium, and ruthenium) and... metal* Quantity Deliverable item (NSN and nomenclature)!!rs *If platinum or palladium, specify...

  9. 48 CFR 252.208-7000 - Intent to furnish precious metals as Government-furnished material.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Offeror shall cite the type (silver, gold, platinum, palladium, iridium, rhodium, and ruthenium) and... metal* Quantity Deliverable item (NSN and nomenclature)!!rs *If platinum or palladium, specify...

  10. A critical evaluation of the performance of triphenylphosphine and N,N' -diphenylthiourea in solvent extraction concentration of precious metals for ICAP-AES analysis

    NASA Astrophysics Data System (ADS)

    Seeverens, P. J. H.; Klaassen, E. J. M.; Maessen, F. J. M. J.

    In view of the capability of Inductively Coupled Argon Plasma-Atomic Emission Spectrometry (ICAPAES) for simultaneous multi-element analysis group extraction of trace elements is of special importance. Group extraction of precious metals using the complexing agents N, N'-diphenylthiourea (DPTU)and triphenylphosphine (TPP) was systematically investigated. From the results it appeared that platinum, palladium, gold and silver were selectively extracted as a group without the need of a labilizing agent. Direct ICAP-AES analysis of the organic extracts turned out to be feasible, but experimentally the analysis of organic solutions was much less straightforward compared to aqueous solutions. A procedure was tested to transfer the metals back into aqueous solution. The extraction procedure using both DPTU and TPP in solvent extraction of precious metals for ICAP-AES analysis has been applied to a certified platinum ore. The results showed a good agreement with the certificate.

  11. Colloidal transport of gold and silica in epithermal precious-metal systems: Evidence from the Sleeper deposit, Nevada

    NASA Astrophysics Data System (ADS)

    Saunders, James A.

    1990-08-01

    Bonanza-vein gold ore from the Sleeper deposit, Nevada, was deposited at a depth of less than 500 m and exhibits a characteristic texture of alternating colloform bands of fine-grained quartz and bands of opaline silica containing abundant electrum. Textural evidence indicates that the quartz bands recrystallized from a gel-like amorphous precursor, whereas the gold-rich bands were deposited originally as amorphous precipitate formed by the coagulation of colloidal silica and gold particles. Gold and silica precipitated initially as colloidal particles at deeper levels in the hydrothermal system and were mechanically transported upward by the hydraulic action of the ore-forming fluids. Coagulation of the colloidal particles may have been caused by solution cooling or boiling, and catalyzed by hydrated polycationic Al3+ aqueous species. Transport of gold as colloidal particles in epithermal systems indicates that, at least in some instances, higher gold content is possible than in true solution. A gold-enriched ore fluid appears necessary to explain the origin of the bonanza-grade ore at the Sleeper mine, and the colloidal gold transport process locally might have played a role in the genesis of the more-common disseminated epithermal precious-metal deposits.

  12. Elucidating Oxygen Reduction Active Sites in Pyrolyzed Metal–Nitrogen Coordinated Non-Precious-Metal Electrocatalyst Systems

    PubMed Central

    2015-01-01

    Detailed understanding of the nature of the active centers in non-precious-metal-based electrocatalyst, and their role in oxygen reduction reaction (ORR) mechanistic pathways will have a profound effect on successful commercialization of emission-free energy devices such as fuel cells. Recently, using pyrolyzed model structures of iron porphyrins, we have demonstrated that a covalent integration of the Fe–Nx sites into π-conjugated carbon basal plane modifies electron donating/withdrawing capability of the carbonaceous ligand, consequently improving ORR activity. Here, we employ a combination of in situ X-ray spectroscopy and electrochemical methods to identify the various structural and functional forms of the active centers in non-heme Fe/N/C catalysts. Both methods corroboratively confirm the single site 2e– × 2e– mechanism in alkaline media on the primary Fe2+–N4 centers and the dual-site 2e– × 2e– mechanism in acid media with the significant role of the surface bound coexisting Fe/FexOy nanoparticles (NPs) as the secondary active sites. PMID:24817921

  13. Phytoremediation of the toxic effluent generated during recovery of precious metals from polymetallic sea nodules.

    PubMed

    Vaseem, Huma; Banerjee, T K

    2012-01-01

    Recovery of metals from the polymetallic sea nodules at the pilot plant at National Metallurgical Laboratory, Jamshedpur, India has generated a highly toxic effluent. This effluent contains several metals like Mn, Cu, Zn, Fe, Pb, Cr, and Cd that pollute the neighboring water bodies when discharged. Hence detoxification of this effluent was practiced using two plants: Lemna minor and Azolla pinnata for 7 days. During investigation A. pinnata removed 96% of Mn, 97% of Cu, 98% of Zn, 70% of Fe, 96% of Pb, 93% of Cr, 78% of Cd, and was comparatively more effective than L. minor which removed 94% of Mn, 86% of Cu, 62% of Zn, 74% of Fe, 84% of Pb, 63% of Cr, 78% of Cd. During the 7 days of experiment chlorophyll content decreased by 51% and 59% in A. pinnata and L. minor respectively. Based on our findings we can suggest that these two plants have wide range of metal retention potentialities hence can be of routine use for purification of toxic effluents. PMID:22567724

  14. Empirical Approach for Estimating Reference Material Heterogeneity and Sample Minimum Test Portion Mass for "Nuggety" Precious Metals (Au, Pd, Ir, Pt, Ru).

    PubMed

    Bédard, L Paul; Esbensen, Kim H; Barnes, Sarah-Jane

    2016-04-01

    Quantification of precious metal content is important for studies of ore deposits, basalt petrogenesis, and precious metal geology, mineralization, mining, and processing. However, accurate determination of metal concentrations can be compromised by microheterogeneity commonly referred to as the "nugget effect", i.e., spatially significant variations in the distribution of precious metal minerals at the scale of instrumental analytical beam footprints. There are few studies focused on the spatial distribution of such minerals and its detrimental effects on quantification of the existing suite of relevant reference materials (RM). In order to assess the nugget effect in RM, pressed powder pellets of MASS-1, MASS-3, WMS-1a, WMS-1, and KPT-1 (dominantly sulfides) as well as CHR-Pt+ and CHR-Bkg (chromite-bearing) were mapped with micro-XRF. The number of verified nuggets observed was used to recalculate an effective concentration of precious metals for the analytical aliquot, allowing for an empirical estimate of a minimum mass test portion. MASS-1, MASS-3, and WMS-1a did not contain any nuggets; therefore, a convenient small test portion could be used here (<0.1 g), while CHR-Pt+ would require 0.125 g and WMS-1 would need 23 g to be representative. For CHR-Bkg and KPT-1, the minimum test portion mass would have to be ∼80 and ∼342 g, respectively. Minimum test portions masses may have to be greater still in order to provide detectable analytical signals. Procedures for counteracting the detrimental manifestations of microheterogeneity are presented. It is imperative that both RM and pristine samples are treated in exactly the same way in the laboratory, lest powders having an unknown nugget status (in effect all field samples for analysis) can not be documented to be representing a safe minimum mass basis. PMID:26910125

  15. Selenium, tellurium and precious metal mineralogy in Uchalinsk copper-zinc-pyritic district, the Urals

    NASA Astrophysics Data System (ADS)

    Vikentev, I.

    2016-04-01

    During processing the most of Au, Ag, Se, Te, Pb, Bi, Sb, Hg as well as notable part of Cu, Zn and Cd fail for tailings and became heavy metal pollutants. Modes of occurrence of Au, Ag, Te and Se covers two giant VMS deposits: Uchaly (intensively deformed) and Uzelginsk (altered by late hydrothermal processes) as well as middle-sized Molodezn and West Ozern deposits (nondeformed) have been studied. Mineral forms of these elements as well as their presence in disperse mode in common ore minerals (pyrite, chalcopyrite, sphalerite) have been studied using SEM, EPMA, INAA, ICP-MS and LA-ICP-MS.

  16. Precious metal oxides for electrochemical energy converters: Pseudocapacitance and pH dependence of redox processes

    NASA Astrophysics Data System (ADS)

    Kurzweil, P.

    The mechanism of charge storage in hydrous platinum metal oxides is considered in more detail with respect to the pH dependence of redox capacitance for applications in double-layer capacitors, fuel cells, and pH sensors. An amorphous RuO 2 electrode is able to work like a pH glass electrode during the titration of hydrochloric acid with sodium hydroxide solution. It is shown that the proton exchange mechanism at a glass membrane can be reproduced by platinum metal oxide-hydrates bound in a polymer matrix. Hydrous RuO 2, obtained by alkaline precipitation or thermal decomposition from RuCl 3, as well as single crystal RuO 2, were characterized by TOF-SIMS, NMR spectroscopy, and electrochemical techniques. The proton conductivity of hydrous RuO 2 appears to be due to the dissociative adsorption of water and the formation of acidic OH groups in Ru(III,IV) cluster ions. Depending on the pH of the solution, the electrode potential is determined by the formal hydrogen oxidation or oxygen reduction in ruthenium cluster ions. During aging, the active Ru(III) surface sites are partially oxidized to Ru(IV).

  17. The Genesis of Precious and Base Metal Mineralization at the Miguel Auza Deposit, Zacatecas, Mexico

    NASA Astrophysics Data System (ADS)

    Findley, A. A.; Olivo, G. R.; Godin, L.

    2009-05-01

    The Miguel Auza mine located in Zacatecas State, Mexico, is a vein-type polymetallic epithermal deposit hosted in deformed argillite, siltstone and, greywacke of the Cretaceous Caracol Formation. Silver-rich base metal veins (0.2 m to >1.5 m wide) are spatially associated with the NE-striking, steeply SE- dipping (70-80°) Miguel Auza fault over a strike length of 1.6 km and a depth of 460 m. A 2 km2 monzonitic stock located in the proximity of the mineralized zones, has previously been interpreted as the source of the mineralizing fluids. Four distinct structural stages are correlated with hydrothermal mineral deposition: (I) The Pre-ore stage is characterized by normal faulting, fracturing of host rock, and rotation of bedding planes. This stage consists of quartz, illite, chlorite, +/- pyrite alteration of sedimentary wall rocks. (II) The Pyrite-vein stage is associated with reverse-sense reactivation of early normal faults, dilation of bedding planes/fractures, and deposition of generally barren calcite + pyrite veinlets. (III) The Main-ore stage is related to the development of reverse-fault- hosted massive sulphide veins. During this stage three phases of mineral deposition are recorded: early pyrite and arsenopyrite, intermediate chalcopyrite, pyrite, arsenopyrite, and base metals, and late base metals and Ag-bearing minerals. Associated gangue minerals during the main ore stage are quartz, muscovite, calcite and chlorite. (IV) The Post-ore stage involves late NW-SE striking block faulting, brecciation and calcite veining. Later supergene oxidation of veins led to deposition of Fe-oxides and hydroxides, commonly filling fractures or replacing early-formed sulphide assemblages. The various vein types display classic epithermal textures including open space filling, banding, comb quartz and brecciation. The Ag-bearing minerals comprise pyrargyrite [Ag3(Sb,As)S3], argentotennantite [(Cu,Ag)10(Zn,Fe)2(Sn,As)4S13], polybasite-pearceite [(Ag,Cu)16(Sb,As)2S11], and

  18. Incorporation of precious metal nanoparticles into various aerogels by different supercritical deposition methods

    NASA Astrophysics Data System (ADS)

    Saquing, Carl D.

    2005-11-01

    One major hurdle in nanoparticle fabrication is the difficulty in controlling size, distribution and concentration. Conventional methods in nanoparticle formation require high temperatures which lead to particle agglomeration and size broadening, or involve substantial amount of organic solvents. A clean route to supported-nanoparticles fabrication was investigated using various supercritical (SC) based deposition methods. The SC deposition involves the organometallic precursor (OP) (dimethyl(1,5-cyclooctadiene)platinum(II)[CODPtMe 2] or bis(2,2,6,6-tetramethyl-3,5-heptanedionato) (1,5-cyclooctadiene) ruthenium(II)) dissolution in SC fluid and contacting this solution with a substrate. The OP is adsorbed and subsequent reduction of the OP-impregnated substrate produces metal/substrate composites. The various methods were: (1) thermal reduction at atmospheric pressure in an inert atmosphere; (2) thermal reduction in SC carbon dioxide (scCO2); (3) chemical reduction in scCO2 with H2; and (4) chemical reduction at atmospheric pressure with H2. The synthesis of resorcinol-formaldehyde aerogels (RFAs) and carbon aerogels (CAs) was also studied and used as substrates (along with commercial silica aerogels (SAs)) in the SC deposition. The surface area, pore properties, and density of these aerogels were evaluated and the effects of reactant concentration, pyrolysis and SC deposition on these properties were determined. Using a static method, the adsorption isotherms of CODPtMe2 in scCO2 on two CAs with different pore sizes were measured at 28 MPa and 80°C to determine the maximum metal loading and the effect of pore properties on adsorption and to examine the interactions between the three components. The isotherms could be represented by the Langmuir model and the adsorption data indicated a strong CODPtMe2-CA interaction and that almost all the preexistent micropore area was covered with CODPtMe 2 molecules even at adsorption lower than the maximum capacity. The

  19. The Cuenca de Oro, a Pull-Apart Basin Hosting Precious Metal Deposits Along the Re- Activated Seri-Tahue Terrane Boundary

    NASA Astrophysics Data System (ADS)

    Feinstein, M. N.; Goodell, P. C.

    2007-05-01

    At the intersection of Chihuahua, Sonora, and Sinaloa a boundary between the Seri and Tahue terranes has been hypothesized, and further refined as the Sinforosa Lineament. Near the western termination of the Sinforosa Lineament lies a topographic basin. Part of this study will be to better define this pull-apart basin, informally named the Cuenca de Oro due to its numerous precious metal deposits. The intention of this study is to test that the Seri-Tahue terrane boundary was re-energized during the beginning of extension related to the opening of the Sea of Cortez (~30ma). It is probable that the precious metal occurrences are related to the initiation of extension(alunite at El Sauzal has been dated at ~30ma). Five field excursions totaling sixty days of field work have been completed and a first draft of a regional geologic map has been made. Large shear zones support the hypothesis of a pull-apart basin. A study of the alteration and lineament intersections determine the location of many known precious metal deposits. By creating multiple cross-sections the basin can be modeled in three dimensions and a tectonic history can be interpreted. This study will present a structural analysis of the Cuenca de Oro and develop a tectonic history related temporally with the epithermal mineralization events.

  20. Nickel oxide and carbon nanotube composite (NiO/CNT) as a novel cathode non-precious metal catalyst in microbial fuel cells.

    PubMed

    Huang, Jianjian; Zhu, Nengwu; Yang, Tingting; Zhang, Taiping; Wu, Pingxiao; Dang, Zhi

    2015-10-15

    Comparing with the precious metal catalysts, non-precious metal catalysts were preferred to use in microbial fuel cells (MFCs) due to the low cost and high oxygen reduction reaction (ORR) efficiency. In this study, the transmission electron microscope and X-ray diffraction as well as Raman investigation revealed that the prepared nanoscale NiO was attached on the surface of CNT. Cyclic voltammogram and rotating ring-disk electrode tests showed that the NiO/CNT composite catalyst had an apparent oxygen reduction peak and 3.5 electron transfer pathway was acquired under oxygen atmosphere. The catalyst performance was highly dependent on the percentage of NiO in the CNT nanocomposites. When 77% NiO/CNT nano-sized composite was applied as cathode catalyst in membrane free single-chamber air cathode MFC, a maximum power density of 670 mW/m(2) and 0.772 V of OCV was obtained. Moreover, the MFC with pure NiO (control) could not achieve more than 0.1 V. All findings suggested that NiO/CNT could be a potential cathode catalyst for ORR in MFCs. PMID:26002018

  1. Ages and sources of components of Zn-Pb, Cu, precious metal, and platinum group element deposits in the goodsprings district, clark county, Nevada

    USGS Publications Warehouse

    Vikre, P.; Browne, Q.J.; Fleck, R.; Hofstra, A.; Wooden, J.

    2011-01-01

    The Goodsprings district, Clark County, Nevada, includes zinc-dominant carbonate replacement deposits of probable late Paleozoic age, and lead-dominant carbonate replacement deposits, copper ?? precious metal-platinum group element (PGE) deposits, and gold ?? silver deposits that are spatially associated with Late Triassic porphyritic intrusions. The district encompasses ??500 km2 although the distribution of all deposits has been laterally condensed by late Mesozoic crustal contraction. Zinc, Pb, and Cu production from about 90 deposits was ??160,000 metric tons (t) (Zn > Pb >> Cu), 2.1 million ounces (Moz) Ag, 0.09 Moz Au, and small amounts of PGEs-Co, V, Hg, Sb, Ni, Mo, Mn, Ir, and U-were also recovered. Zinc-dominant carbonate replacement deposits (Zn > Pb; Ag ?? Cu) resemble Mississippi Valley Type (MVT) Zn-Pb deposits in that they occur in karst and fault breccias in Mississippian limestone where the southern margin of the regional late Paleozoic foreland basin adjoins Proterozoic crystalline rocks of the craton. They consist of calcite, dolomite, sphalerite, and galena with variably positive S isotope compositions (??34S values range from 2.5-13%), and highly radiogenic Pb isotope compositions (206Pb/204Pb >19), typical of MVT deposits above crystalline Precambrian basement. These deposits may have formed when southward flow of saline fluids, derived from basinal and older sedimentary rocks, encountered thinner strata and pinch-outs against the craton, forcing fluid mixing and mineral precipitation in karst and fault breccias. Lead-dominant carbonate replacement deposits (Pb > Zn, Ag ?? Cu ?? Au) occur among other deposit types, often near porphyritic intrusions. They generally contain higher concentrations of precious metals than zinc-dominant deposits and relatively abundant iron oxides after pyrite. They share characteristics with copper ?? precious metal- PGE and gold ?? silver deposits including fine-grained quartz replacement of carbonate minerals in

  2. Hierarchical nanostructured NiCo2O4 as an efficient bifunctional non-precious metal catalyst for rechargeable zinc-air batteries.

    PubMed

    Prabu, Moni; Ketpang, Kriangsak; Shanmugam, Sangaraju

    2014-03-21

    A nickel-doped cobalt oxide spinel structure is a promising non-precious metal electrocatalyst for oxygen evolution and oxygen reduction in rechargeable metal-air batteries and water electrolyzers operating with alkaline electrolytes. One dimensional NiCo2O4 (NCO) nanostructures were prepared by using a simple electrospinning technique with two different metal precursors (metal nitrate/PAN and metal acetylacetonate/PAN). The effect of precursor concentration on the morphologies was investigated. Single-phase, NCO with an average diameter of 100 nm, porous interconnected fibrous morphology was revealed by FESEM and FETEM analysis. The hierarchical nanostructured 1D-spinel NiCo2O4 materials showed a remarkable electrocatalytic activity towards oxygen reduction and evolution in an aqueous alkaline medium. The extraordinary bi-functional catalytic activity towards both ORR and OER was observed by the low over potential (0.84 V), which is better than that of noble metal catalysts [Pt/C (1.16 V), Ru/C (1.01 V) and Ir/C (0.92 V)], making them promising cathode materials for metal-air batteries. Furthermore, the rechargeable zinc-air battery with NCO-A1 as a bifunctional electrocatalyst displays high activity and stability during battery discharge, charge, and cycling processes. PMID:24496578

  3. Mineral Deposit Data for Epigenetic Base- and Precious-metal and Uranium-thorium Deposits in South-central and Southwestern Montana and Southern and Central Idaho

    USGS Publications Warehouse

    Klein, T.L.

    2004-01-01

    Metal deposits spatially associated with the Cretaceous Boulder and Idaho batholiths of southwestern Montana and southern and central Idaho have been exploited since the early 1860s. Au was first discovered in placer deposits; exploitation of vein deposits in bedrock soon followed. In 1865, high-grade Ag vein deposits were discovered and remained economically important until the 1890s. Early high-grade deposits of Au, Ag and Pb were found in the weathered portions of the veins systems. As mining progressed to deeper levels, Ag and Pb grades diminished. Exploration for and development of these vein deposits in this area have continued until the present. A majority of these base- and precious-metal vein deposits are classified as polymetallic veins (PMV) and polymetallic carbonate-replacement (PMR) deposits in this compilation. Porphyry Cu and Mo, epithermal (Au, Ag, Hg and Sb), base- and precious-metal and W skarn, W vein, and U and Th vein deposits are also common in this area. The world-class Butte Cu porphyry and the Butte high-sulfidation Cu vein deposits are in this study area. PMV and PMR deposits are the most numerous in the region and constitute about 85% of the deposit records compiled. Several types of syngenetic/diagenetic sulfide mineral deposits in rocks of the Belt Supergroup or their equivalents are common in the region and they have been the source of a substantial metal production over the last century. These syngenetic deposits and their metamorphosed/structurally remobilized equivalents were not included in this database; therefore, deposits in the Idaho portion of the Coeur d'Alene district and the Idaho Cobalt belt, for example, have not been included because many of them are believed to be of this type.

  4. Recovery of precious metals from low-grade automobile shredder residue: A novel approach for the recovery of nanozero-valent copper particles.

    PubMed

    Singh, Jiwan; Lee, Byeong-Kyu

    2016-02-01

    The presence of precious metals (PMs) in low-grade automobile shredder residue (ASR) makes it attractive for recycling. This study investigated the leaching and recovery characteristics of two PMs (Cu and Ag) and two heavy metals (Mn and Co) from ASR. The effects of H2O2, leaching temperature, liquid to solid (L/S) ratio, and particle size on metal leaching were determined in an aqueous solution of 0.5M nitric acid. The metal leaching rate was increased with increasing nitric acid concentration, amount of H2O2, L/S ratio and temperature. The leaching kinetics was analyzed by using a second-order reaction model. In the analysis of leaching kinetics, the metal leaching data were well fitted (R(2)⩾0.99) with the second-order reaction model. The activation energy (kJ/mol) for metal leaching was 39.6 for Cu, 17.1 for Ag, 17.3 for Mn and 29.2 for Co. Metal recovery was carried out by fractional precipitation with the addition of advanced Fenton's regent. Metal recovery efficiency was increased to 99.95% for Cu, 99.8% for Mn, 90.0% for Ag and 96.46% for Co with the advanced Fenton's regent. In particular, a novel finding of the PM recovery is that Cu can also be recovered directly from the leachate of ASR in the form of zero-valent copper (ZVC) nanoparticles (NPs). Hydrometallurgical recovery of the metals from ASR using nitric acid is highly efficient. PMID:26525968

  5. XPS study on the weakest zone in the adhesion structure between resin containing 4-META and precious metal alloys treated with different surface modification methods.

    PubMed

    Ohno, H; Endo, K; Yamane, Y; Kawashima, I

    2001-03-01

    Three precious metal alloys, Type IV gold alloy, 14 K gold alloy, and silver-based alloy, were treated with different surface modifications including a metal primer (VBATDT) application, a SiOx coating method, high-temperature oxidation, modification method with a liquid Ga-Sn alloy, and tin electroplating. Then thin PMMA films were bonded with a resin containing 4-META. Water durability at the adhesion interface was evaluated after water immersion, followed by thermal cycling used liquid nitrogen. The weakest zone at the interface was investigated using XPS only for the Ag-Pd alloy specimens that had been surface-treated with as-polishing, adhesive primer, and the SiOx coating method, since peeling of the PMMA film on the surface of specimens surface-treated by other methods was not observed. Metal elements were detected from the resin side at the adhesion interface. The chemical states of Cu in the resin before argon ion etching were characterized as metal oxides and/or states of chemical interaction with 4-META, VBATDT, or SiOx. PMID:11441491

  6. Hierarchical nanostructured NiCo2O4 as an efficient bifunctional non-precious metal catalyst for rechargeable zinc-air batteries

    NASA Astrophysics Data System (ADS)

    Prabu, Moni; Ketpang, Kriangsak; Shanmugam, Sangaraju

    2014-02-01

    A nickel-doped cobalt oxide spinel structure is a promising non-precious metal electrocatalyst for oxygen evolution and oxygen reduction in rechargeable metal-air batteries and water electrolyzers operating with alkaline electrolytes. One dimensional NiCo2O4 (NCO) nanostructures were prepared by using a simple electrospinning technique with two different metal precursors (metal nitrate/PAN and metal acetylacetonate/PAN). The effect of precursor concentration on the morphologies was investigated. Single-phase, NCO with an average diameter of 100 nm, porous interconnected fibrous morphology was revealed by FESEM and FETEM analysis. The hierarchical nanostructured 1D-spinel NiCo2O4 materials showed a remarkable electrocatalytic activity towards oxygen reduction and evolution in an aqueous alkaline medium. The extraordinary bi-functional catalytic activity towards both ORR and OER was observed by the low over potential (0.84 V), which is better than that of noble metal catalysts [Pt/C (1.16 V), Ru/C (1.01 V) and Ir/C (0.92 V)], making them promising cathode materials for metal-air batteries. Furthermore, the rechargeable zinc-air battery with NCO-A1 as a bifunctional electrocatalyst displays high activity and stability during battery discharge, charge, and cycling processes.A nickel-doped cobalt oxide spinel structure is a promising non-precious metal electrocatalyst for oxygen evolution and oxygen reduction in rechargeable metal-air batteries and water electrolyzers operating with alkaline electrolytes. One dimensional NiCo2O4 (NCO) nanostructures were prepared by using a simple electrospinning technique with two different metal precursors (metal nitrate/PAN and metal acetylacetonate/PAN). The effect of precursor concentration on the morphologies was investigated. Single-phase, NCO with an average diameter of 100 nm, porous interconnected fibrous morphology was revealed by FESEM and FETEM analysis. The hierarchical nanostructured 1D-spinel NiCo2O4 materials showed a

  7. A review of the stability and durability of non-precious metal catalysts for the oxygen reduction reaction in proton exchange membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Banham, Dustin; Ye, Siyu; Pei, Katie; Ozaki, Jun-ichi; Kishimoto, Takeaki; Imashiro, Yasuo

    2015-07-01

    A major hurdle to the widespread commercialization of proton exchange membrane fuel cells (PEMFCs) is the high loading of noble metal (Pt/Pt-alloy) catalyst at the cathode, which is necessary to facilitate the inherently sluggish oxygen reduction reaction (ORR). To eliminate the use of Pt/Pt-alloy catalysts at the cathode of PEMFCs and thus significantly reduce the cost, extensive research on non-precious metal catalysts (NPMCs) has been carried out over the past decade. Major advances in improving the ORR activity of NPMCs, particularly Fe- and Co-based NPMCs, have elevated these materials to a level at which they can start to be considered as potential alternatives to Pt/Pt-alloy catalysts. Unfortunately, the stability (performance loss following galvanostatic experiments) of these materials is currently unacceptably low and the durability (performance loss following voltage cycling) remains uncertain. The three primary mechanisms of instability are: (a) Leaching of the metal site, (b) Oxidative attack by H2O2, and (c) Protonation followed by possible anion adsorption of the active site. While (a) has largely been solved, further work is required to understand and prevent losses from (b) and/or (c). Thus, this review is focused on historical progress in (and possible future strategies for) improving the stability/durability of NPMCs.

  8. Biorefining of precious metals from wastes: an answer to manufacturing of cheap nanocatalysts for fuel cells and power generation via an integrated biorefinery?

    PubMed

    Yong, Ping; Mikheenko, Iryna P; Deplanche, Kevin; Redwood, Mark D; Macaskie, Lynne E

    2010-12-01

    Bio-manufacturing of nano-scale palladium was achieved via enzymatically-mediated deposition of Pd from solution using Desulfovibrio desulfuricans, Escherichia coli and Cupriavidus metallidurans. Dried 'Bio-Pd' materials were sintered, applied onto carbon papers and tested as anodes in a proton exchange membrane (PEM) fuel cell for power production. At a Pd(0) loading of 25% by mass the fuel cell power using Bio-Pd( D. desulfuricans ) (positive control) and Bio-Pd( E. coli ) (negative control) was ~140 and ~30 mW respectively. Bio-Pd( C. metallidurans ) was intermediate between these with a power output of ~60 mW. An engineered strain of E. coli (IC007) was previously reported to give a Bio-Pd that was >3-fold more active than Bio-Pd of the parent E. coli MC4100 (i.e. a power output of >110 mW). Using this strain, a mixed metallic catalyst was manufactured from an industrial processing waste. This 'Bio-precious metal' ('Bio-PM') gave ~68% of the power output as commercial Pd(0) and ~50% of that of Bio-Pd( D. desulfuricans ) when used as fuel cell anodic material. The results are discussed in relation to integrated bioprocessing for clean energy. PMID:20734111

  9. Cobalt and precious metals in sulphides of peridotite xenoliths and inferences concerning their distribution according to geodynamic environment: A case study from the Scottish lithospheric mantle

    NASA Astrophysics Data System (ADS)

    Hughes, Hannah S. R.; McDonald, Iain; Faithfull, John W.; Upton, Brian G. J.; Loocke, Matthew

    2016-01-01

    Abundances of precious metals and cobalt in the lithospheric mantle are typically obtained by bulk geochemical analyses of mantle xenoliths. These elements are strongly chalcophile and the mineralogy, texture and trace element composition of sulphide phases in such samples must be considered. In this study we assess the mineralogy, textures and trace element compositions of sulphides in spinel lherzolites from four Scottish lithospheric terranes, which provide an ideal testing ground to examine the variability of sulphides and their precious metal endowments according to terrane age and geodynamic environment. Specifically we test differences in sulphide composition from Archaean-Palaeoproterozoic cratonic sub-continental lithospheric mantle (SCLM) in northern terranes vs. Palaeozoic lithospheric mantle in southern terranes, as divided by the Great Glen Fault (GGF). Cobalt is consistently elevated in sulphides from Palaeozoic terranes (south of the GGF) with Co concentrations > 2.9 wt.% and Co/Ni ratios > 0.048 (chondrite). In contrast, sulphides from Archaean cratonic terranes (north of the GGF) have low abundances of Co (< 3600 ppm) and low Co/Ni ratios (< 0.030). The causes for Co enrichment remain unclear, but we highlight that globally significant Co mineralisation is associated with ophiolites (e.g., Bou Azzer, Morocco and Outokumpu, Finland) or in oceanic peridotite-floored settings at slow-spreading ridges. Thus we suggest an oceanic affinity for the Co enrichment in the southern terranes of Scotland, likely directly related to the subduction of Co-enriched oceanic crust during the Caledonian Orogeny. Further, we identify a distinction between Pt/Pd ratio across the GGF, such that sulphides in the cratonic SCLM have Pt/Pd ≥ chondrite whilst Palaeozoic sulphides have Pt/Pd < chondrite. We observe that Pt-rich sulphides with discrete Pt-minerals (e.g., PtS) are associated with carbonate and phosphates in two xenolith suites north of the GGF. This three

  10. Metallogeny of precious and base metal mineralization in the Murchison Greenstone Belt, South Africa: indications from U-Pb and Pb-Pb geochronology

    NASA Astrophysics Data System (ADS)

    Jaguin, J.; Poujol, M.; Boulvais, P.; Robb, L. J.; Paquette, J. L.

    2012-10-01

    The 3.09 to 2.97 Ga Murchison Greenstone Belt is an important metallotect in the northern Kaapvaal Craton (South Africa), hosting several precious and base metal deposits. Central to the metallotect is the Antimony Line, striking ENE for over 35 km, which hosts a series of structurally controlled Sb-Au deposits. To the north of the Antimony Line, hosted within felsic volcanic rocks, is the Copper-Zinc Line where a series of small, ca. 2.97 Ga Cu-Zn volcanogenic massive sulfide (VMS)-type deposits occur. New data are provided for the Malati Pump gold mine, located at the eastern end of the Antimony Line. Crystallizations of a granodiorite in the Malati Pump Mine and of the Baderoukwe granodiorite are dated at 2,964 ± 7 and 2,970 ± 7 Ma, respectively (zircon U-Pb), while pyrite associated with gold mineralization yielded a Pb-Pb age of 2,967 ± 48 Ma. Therefore, granodiorite emplacement, sulfide mineral deposition and gold mineralization all happened at ca. 2.97 Ga. It is, thus, suggested that the major styles of orogenic Au-Sb and the Cu-Zn VMS mineralization in the Murchison Greenstone Belt are contemporaneous and that the formation of meso- to epithermal Au-Sb mineralization at fairly shallow levels was accompanied by submarine extrusion of felsic volcanic rocks to form associated Cu-Zn VMS mineralization.

  11. Chronic beryllium disease in a precious metal refinery. Clinical epidemiologic and immunologic evidence for continuing risk from exposure to low level beryllium fumes

    SciTech Connect

    Cullen, M.R.; Kominsky, J.R.; Rossman, M.D.; Cherniack, M.G.; Rankin, J.A.; Balmes, J.R.; Kern, J.A.; Daniele, R.P.; Palmer, L.; Naegel, G.P.

    1987-01-01

    Five workers at a precious metal refinery developed granulomatous lung disease between 1972 and 1985. The original diagnosis was sarcoidosis, but 4 of the workers were subsequently proved to have hypersensitivity to beryllium by in vitro proliferative responses of lymphocytes obtained by bronchoalveolar lavage. Review of medical records of coworkers and extensive industrial hygiene surveillance of the plant demonstrated that 4 cases occurred in the furnace area where air concentrations of beryllium fume were consistently below the permissible exposure limit of 2 micrograms/M3. A single case has been recognized from parts of the refinery where exposures to cold beryllium dust often exceeded the standard by as much as 20-fold. These data demonstrate that chronic beryllium disease still occurs and confirm the importance of specific immunologic testing in patients suspected of having sarcoidosis but with potential exposure to beryllium. The data raise concern about the adequacy of modern industrial controls, especially in the setting of exposure to highly respirable beryllium fumes.

  12. Non-precious metal nanoparticles supported on nitrogen-doped graphene as a promising catalyst for oxygen reduction reaction: Synthesis, characterization and electrocatalytic performance

    NASA Astrophysics Data System (ADS)

    Ghanbarlou, Hosna; Rowshanzamir, Soosan; Kazeminasab, Bagher; Parnian, Mohammad Javad

    2015-01-01

    Nitrogen-doped graphene (NG) based non-precious metal catalysts is used as a catalyst for oxygen reduction reaction (ORR). Nanoflower-like NG with designed nitrogen types is directly synthesized using a low temperature solvothermal process and then Fe, Co and Fe-Co nanoparticles are precipitated onto the NG using a modified polyol method. The morphology of the NG is studied using scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. The synthesized M/NG (M = Fe, Co, Fe-Co) electrocatalysts are characterized using transmission electron microscopy, X-ray diffraction and energy-dispersive X-ray spectroscopy. Electrochemical characterizations reveal that NG acts as a catalyst for ORR in an alkaline solution. The electrocatalytic properties of NG and M/NG catalysts are investigated for ORR in 0.1 M KOH. Cyclic voltammetry, linear sweep voltammetry and electrochemical impedance spectroscopy are used to measure electrocatalytic activity. M/NG catalysts exhibit higher electrocatalytic activity than NG and the highest activity is observed for the Co/NG electrode. Chronoamperometric results demonstrate that the Co/NG catalyst is more stable than commercial Pt/C for ORR in an alkaline solution.

  13. Iron- and nitrogen-functionalized graphene as a non-precious metal catalyst for enhanced oxygen reduction in an air-cathode microbial fuel cell

    NASA Astrophysics Data System (ADS)

    Li, Sizhe; Hu, Yongyou; Xu, Qian; Sun, Jian; Hou, Bin; Zhang, Yaping

    2012-09-01

    In this work, iron- and nitrogen-functionalized graphene (Fe-N-G) as a non-precious metal catalyst is synthesized via a facile method of thermal treatment of a mixture of Fe salt, graphitic carbon nitride (g-C3N4) and chemically reduced graphene. The electrocatalytic activity of the prepared catalysts toward oxygen reduction reaction (ORR) evaluated by using linear sweep voltammetry tests shows that the Fe-N-G catalyst has more positive onset potential and increased reduction current densities as compared to the pristine graphene (P-G) catalyst, indicating an enhanced ORR activity of the Fe-N-G catalyst. More importantly, the Fe-N-G-MFC achieves the highest power density of 1149.8 mW m-2, which is ∼2.1 times of that generated with the Pt/C-MFC (561.1 mW m-2) and much higher than that of the P-G-MFC (109 mW m-2). These results demonstrate that the Fe-N-G catalyst can hold the promise of being an excellent alternative to the costly Pt catalyst for practical MFC applications.

  14. Non-Precious Metals Catalyze Formal [4 + 2] Cycloaddition Reactions of 1,2-Diazines and Siloxyalkynes under Ambient Conditions

    PubMed Central

    2015-01-01

    Copper(I) and nickel(0) complexes catalyze the formal [4 + 2] cycloaddition reactions of 1,2-diazines and siloxyalkynes, a reaction hitherto best catalyzed by silver salts. These catalysts based on earth abundant metals are not only competent, but the copper catalyst, in particular, promotes cycloadditions of pyrido[2,3-d]pyridazine and pyrido[3,4-d]pyridazine, enabling a new synthesis of quinoline and isoquinoline derivatives, as well as the formal [2 + 2] cycloaddition reaction of cyclohexenone with a siloxyalkyne. PMID:24911346

  15. Geology and K-Ar geochronology of the Paradise Peak Mine and the relationship of pre-Basin and Range extension to Early Miocene precious metal mineralization in west-central Nevada

    USGS Publications Warehouse

    John, D.A.; Thomason, R.E.; McKee, E.H.

    1989-01-01

    The Paradise Peak mine is a major gold-silver-mercury deposit located in the southwestern part of the Paradise Range near the eastern edge of the Walker Lane in the western Great Basin, Nevada. Regional stratigraphic relations and K-Ar ages indicate that volcanism changed from silicic ash-flow tuffs to intermediate lavas at about 20 to 19 Ma. Regionally extensive angular unconformities indicate that a period of "pre-Basin and Range' crustal extension occurred between about 22 to 19 Ma. This extension was penecontemporaneous with the shift in the style of volcanism and with gold-silver mineralization in the Paradise Peak mine and in the Goldfield and Tonopah districts of western Nevada. The close temporal and spatial relationships of precious metal mineralization with pre-Basin and Range extension suggest that extension was a major factor in the genesis of early Miocene precious metal deposits in the western Great Basin. -from Authors

  16. Copper-zinc alloy nanopowder: a robust precious-metal-free catalyst for the conversion of 5-hydroxymethylfurfural.

    PubMed

    Bottari, Giovanni; Kumalaputri, Angela J; Krawczyk, Krzysztof K; Feringa, Ben L; Heeres, Hero J; Barta, Katalin

    2015-04-24

    Noble-metal-free copper-zinc nanoalloy (<150 nm) is found to be uniquely suited for the highly selective catalytic conversion of 5-hydroxymethylfurfural (HMF) to potential biofuels or chemical building blocks. Clean mixtures of 2,5-dimethylfuran (DMF) and 2,5-dimethyltetrahydrofuran (DMTHF) with combined product yields up to 97 % were obtained at 200-220 °C using 20-30 bar H2 . It is also possible to convert 10 wt % HMF solutions in CPME, with an excellent DMF yield of 90 %. Milder temperatures favor selective (95 %) formation of 2,5-furandimethanol (FDM). The one-pot conversion of fructose to valuable furan-ethers was also explored. Recycling experiments for DMF production show remarkable catalyst stability. Transmission electron microscopy (TEM) characterization provides more insight into morphological changes of this intriguing class of materials during catalysis. PMID:25833148

  17. Age and origin of base and precious metal veins of the Coeur d'Alene mining district, Idaho

    USGS Publications Warehouse

    Fleck, R.J.; Criss, R.E.; Eaton, G.F.; Cleland, R.W.; Wavra, C.S.; Bond, W.D.

    2002-01-01

    Ore-bearing quartz-carbonate veins of the Coeur d'Alene mining district yield 87Sr/86Sr ratios of 0.74 to >1.60 for low Rb/Sr, carbonate gangue minerals, similar to current ranges measured in Middle Proterozoic, high Rb/Sr rocks of the Belt Supergroup. Stable isotope and fluid inclusion studies establish a genetic relationship between vein formation and metamorphic-hydrothermal systems of the region. These extraordinary 87Sr/86Sr ratios require accumulation of radiogenic 87Sr in a high Rb/Sr system over an extended period prior to incorporation of Sr into the hydrothermal veins. Evaluation of the age and composition of potential sources of highly radiogenic Sr indicates that the ore-bearing veins of the Coeur d'Alene district formed during the Cretaceous from components scavenged from rocks of the Belt Supergroup, the primary host rocks of the district. Proterozoic Pb isotope ratios observed in galena from many Coeur d'Alene veins were established when Pb separated from uranium during deposition or diagenesis of the Belt Supergroup at 1400 to 1500 Ma, possibly as disseminated syngenetic deposits. K-Ar and Rb-Sr apparent ages and ??18O values of Belt Supergroup rocks decrease from the Coeur d'Alene district toward the Idaho and Kaniksu batholiths, approximately normal to the trends of metamorphic isograds, fold axes, foliation, and the major reverse faults of the district. Isoclinal folding, thrust faulting, high-temperature metamorphism, granitic plutonism, and regional-scale metamorphic-hydrothermal activity is documented in the region between 140 and 45 Ma, representing the only such combination of events in the Coeur d'Alene region subsequent to about 1300 Ma. The Sr and oxygen results and geologic evidence favor formation of the ore-bearing carbonate veins by fluids related to a complex metamorphic-hydrothermal system during the Cretaceous. Pb with Proterozoic isotopic compositions was probably mobilized and incorporated like other metals into the hydrothermal

  18. Homogeneous deposition-assisted synthesis of iron-nitrogen composites on graphene as highly efficient non-precious metal electrocatalysts for microbial fuel cell power generation

    NASA Astrophysics Data System (ADS)

    Liu, Yuan; Jin, Xiao-Jun; Dionysiou, Dionysios D.; Liu, Hong; Huang, Yu-Ming

    2015-03-01

    This work proposed a novel strategy for synthesizing highly efficient non-precious metal oxygen reduction reaction (ORR) electrocatalysts. Fe complexes were homogeneously deposited (HD) on graphene oxide through in situ hydrolysis of urea, followed by two-step pyrolysis under Ar and NH3 atmospheres, resulting in formation of Fe- and N-functionalized graphene (HD-FeN/G). The morphology, crystalline structure and elemental composition of HD-FeN/G were characterized. ORR activity was evaluated by using a rotary disk electrode (RDE) electrochemical system. HD improved the loading and distribution of the Fe-Nx composites on graphene. The ORR activity of the as-prepared HD-FeN/G in neutral medium was comparable to that of the state-of-the-art commercial Pt/C and significantly superior to a FeN/G counterpart produced via traditional approach. The ORR electron transfer number of HD-FeN/G was as high as 3.83 ± 0.08, which suggested that ORR catalysis proceeds through a four-electron pathway. HD-FeN/G was used as a cathodic electrocatalyst in microbial fuel cells (MFCs), and the resultant HD-FeN/G-MFC showed comparable voltage output and maximum power density to those of Pt/C-MFC. The HD-FeN/G-MFC achieved a maximum power density of 885 mW m-2, which was much higher than that of FeN/G-MFC (708 mW m-2). These findings demonstrate that HD-FeN/G produced through the novel synthesis strategy proposed in this work would be a good candidate as cathodic electrocatalyst in MFCs.

  19. Secondary precious metal enrichment by steam-heated fluids in the Crofoot-Lewis hot spring gold-silver deposit and relation to paleoclimate

    USGS Publications Warehouse

    Ebert, S.W.; Rye, R.O.

    1997-01-01

    controlled largely by basin and range fractures and a high geothermal gradient with H2S for Au complexing derived from organic matter in basin sediments. A wet climate resulted in the formation of a large inland lake which provided abundant recharge water for the hydrothermal system. A fluctuating water table controlled by changing climatic conditions enabled steam-heated acid sulfate fluids to overprint lower grade mineralization resulting in ore-grade precious metal enrichment.

  20. Textural, mineralogical and stable isotope studies of hydrothermal alteration in the main sulfide zone of the Great Dyke, Zimbabwe and the precious metals zone of the Sonju Lake Intrusion, Minnesota, USA

    USGS Publications Warehouse

    Li, C.; Ripley, E.M.; Oberthur, T.; Miller, J.D., Jr.; Joslin, G.D.

    2008-01-01

    Stratigraphic offsets in the peak concentrations of platinum-group elements (PGE) and base-metal sulfides in the main sulfide zone of the Great Dyke and the precious metals zone of the Sonju Lake Intrusion have, in part, been attributed to the interaction between magmatic PGE-bearing base-metal sulfide assemblages and hydrothermal fluids. In this paper, we provide mineralogical and textural evidence that indicates alteration of base-metal sulfides and mobilization of metals and S during hydrothermal alteration in both mineralized intrusions. Stable isotopic data suggest that the fluids involved in the alteration were of magmatic origin in the Great Dyke but that a meteoric water component was involved in the alteration of the Sonju Lake Intrusion. The strong spatial association of platinum-group minerals, principally Pt and Pd sulfides, arsenides, and tellurides, with base-metal sulfide assemblages in the main sulfide zone of the Great Dyke is consistent with residual enrichment of Pt and Pd during hydrothermal alteration. However, such an interpretation is more tenuous for the precious metals zone of the Sonju Lake Intrusion where important Pt and Pd arsenides and antimonides occur as inclusions within individual plagioclase crystals and within alteration assemblages that are free of base-metal sulfides. Our observations suggest that Pt and Pd tellurides, antimonides, and arsenides may form during both magmatic crystallization and subsolidus hydrothermal alteration. Experimental studies of magmatic crystallization and hydrothermal transport/deposition in systems involving arsenides, tellurides, antimonides, and base metal sulfides are needed to better understand the relative importance of magmatic and hydrothermal processes in controlling the distribution of PGE in mineralized layered intrusions of this type. ?? Springer-Verlag 2007.

  1. Public release of optimization of metallization scheme for thin emitter wrap-through solar cells for higher efficiency, reduced precious metal costs, and reduced stress.

    SciTech Connect

    Ruby, Douglas Scott; Murphy, Brian; Meakin, David; Dominguez, Jason; Hacke, Peter

    2008-08-01

    Back-contact crystalline-silicon photovoltaic solar cells and modules offer a number of advantages, including the elimination of grid shadowing losses, reduced cost through use of thinner silicon substrates, simpler module assembly, and improved aesthetics. While the existing edge tab method for interconnecting and stringing edge-connected back contact cells is acceptably straightforward and reliable, there are further gains to be exploited when you have both contact polarities on one side of the cell. In this work, we produce 'busbarless' emitter wrap-through solar cells that use 41% of the gridline silver (Ag) metallization mass compared to the edge tab design. Further, series resistance power losses are reduced by extraction of current from more places on the cell rear, leading to a fill factor improvement of about 6% (relative) on the module level. Series resistance and current-generation losses associated with large rear bondpads and busbars are eliminated. Use of thin silicon (Si) wafers is enabled because of the reduced Ag metallization mass and by interconnection with conductive adhesives leading to reduced bow. The busbarless cell design interconnected with conductive adhesives passes typical International Electrotechnical Commission damp heat and thermal cycling test.

  2. In-vitro study of the adhesive strengths of brackets on metals, ceramic and composite. Part 1: Bonding to precious metals and amalgam.

    PubMed

    Jost-Brinkmann, P G; Drost, C; Can, S

    1996-04-01

    Adult patients often have fillings, artificial crowns and/or bridges that make fitting of conventional bands difficult or even impossible. In such cases bonding rather than banding would be preferable. The present paper presents the investigation of more than 25 resin/conditioner combinations with respect to their bond strength to different metals as well as to amalgam. For that purpose stainless steel lingual buttons were bonded with the various adhesives and their shear bond strengths and types of bond failure were determined after 24 hours. All specimens were air-abraded with 50 microns Al2O3 for 2 or 4 seconds by means of a Microetcher before bonding. For comparison, buttons were also bonded to bovine enamel after air-abrasion or conventional etching with 37% H3PO4. Results show that, on all metals investigated, several materials yield bond strengths which are similar to or higher than what is achieved with the conventional acid etch technique on enamel. Maximum adhesive strength is not always desirable, however, for bonding brackets. The type of bond failure and the risk of irreversible damage to the bonded material have also to be taken into consideration. Al2O3 abrasion may cause considerable damage to enamel within 4 seconds. Since the bond strength on air-abraded enamel is about the same as on acid etched enamel, conventional etching with H3PO4 is preferable to the sandblasting of enamel. PMID:8647560

  3. Geology and geochemistry of epithermal precious metal vein systems in the intra-oceanic arcs of Palau and Yap, western Pacific

    USGS Publications Warehouse

    Rytuba, J.J.; Miller, W.R.

    1990-01-01

    The Palau and Yap arcs are part of an intra-oceanic island-arc-trench system which separates the Pacific and Philippine plates in the western Pacific Ocean. The 350-km-long Palau arc consists of over 200 islands while the 400-km-long Yap arc located to the north has only four major islands exposed. Four of the largest islands in Palau are composed primarily of early Eocene to mid-Miocene volcanic rocks and the four islands comprising Yap contain only Miocene volcanic rocks. Basalt and basaltic andesites of the Babelthuap Formation are the oldest volcanic rocks in Palau and are characterized by high MgO, Ni and Cr and low TiO2 and have a boninitic affinity. They form the central and southeastern parts of Babelthuap Island. Oligocene arc tholeiite flows having an age of 34-35.5 Ma comprise most of the three smaller volcanic islands in Palau and the western part of Babelthuap. The youngest volcanic rocks are dacitic intrusions having an age of 22.7-23.2 Ma. The Yap arc is unusual in that metamorphic rocks up to amphibolite grade form most of the islands. These are underlain by a melange composed of igneous and volcanic clasts as well as clasts from a dismembered copper-gold skarn deposit. Miocene volcanic rocks consisting of flows and volcaniclastic deposits overlie the melange and metamorphic complex. An epithermal precious-metal vein system hosted by flows and flow breccias of the Babelthuap Formation occurs in an area 1.5 km by 1 km on the southeast side of Babelthuap Island. Over 50 veins and mineralized breccias ranging up to 2 m in width and having a strike length up to 500 m contain from trace to 13.0 ppm gold. The veins consist of quartz with varying amounts of sulfides and iron oxides after sulfides and the mineralized breccias consist of brecciated country rock cemented by quartz and iron oxides after sulfides. The veins and mineralized breccias generally dip within 15?? of vertical and have two preferred orientations, north-northwest and north

  4. 3D textural evidence for the formation of ultra-high tenor precious metal bearing sulphide microdroplets in offset reefs: An extreme example from the Platinova Reef, Skaergaard Intrusion, Greenland

    NASA Astrophysics Data System (ADS)

    Holwell, David A.; Barnes, Stephen J.; Le Vaillant, Margaux; Keays, Reid R.; Fisher, Louise A.; Prasser, Richard

    2016-07-01

    The Platinova Reef in the Skaergaard Intrusion, east Greenland, is an example of a type of layered-intrusion-hosted, precious metal-enriched, stratiform, disseminated sulphide deposit referred to as "offset reefs". These typically show platinum-group element (PGE) enrichment immediately below a major increase in the abundance of Cu-rich sulphides, with a prominent peak in Au enrichment exactly at that transition between the PGE-rich and the Cu-sulphide-rich zones. The reasons for the relative sequence of offsets in metal peaks, and the occasionally very high metal tenors have been subject to great debate. Here we use an integrated approach of high-resolution X-ray computed tomography (HRXCT), SEM, synchrotron and desktop microbeam XRF mapping, and thin section petrography to comprehensively classify the textural relations of the precious metal-bearing sulphides of the Platinova Reef as an extreme end member example of an exceedingly high tenor offset deposit. Our results show that in the zones of PGE enrichment, precious metal minerals (PMMs) are intimately associated with Cu sulphide globules, mostly located at, or close to, silicate and oxide boundaries. The textures are identical in zones enriched in Pd and Au, and thus we do not see any evidence for different processes forming the different zones. The PMM:Cu sulphide ratio in each globule varies significantly but overall the size of the globules increases from the Pd-rich, through the Au-rich, and into the Cu zone, with a significant corresponding decrease in PM tenor. As such, this records a progression of exceedingly high tenor, microdroplets of sulphide, which progressively get larger up through the section, and decrease in tenor proportionally to their size. Cumulus droplets of Cu sulphide became enriched in metals, and were trapped in situ without significant transport from their point of nucleation. The transition to larger sulphides represents a change from sulphides nucleated and trapped in situ, to

  5. Use of urchin-like NixCo3-xO4 hierarchical nanostructures based on non-precious metals as bifunctional electrocatalysts for anion-exchange membrane alkaline alcohol fuel cells

    NASA Astrophysics Data System (ADS)

    Manivasakan, Palanisamy; Ramasamy, Parthiban; Kim, Jinkwon

    2014-07-01

    Bifunctional electrocatalysts based on non-precious metals were developed for the dioxygen reduction and methanol oxidation reactions. These electrocatalysts can be considered as candidate cathode and anode materials for anion-exchange membrane (AEM) alkaline alcohol fuel cells. A series of Ni-doped cobalt oxide (NixCo3-xO4) hierarchical nanostructures composed of one-dimensional nanorods was prepared by an inexpensive hydrothermal method. X-ray diffraction patterns showed that the NixCo3-xO4 crystallized in a cubic spinel phase. The electrochemical performance of the catalysts was investigated using a conventional cyclic voltammetry technique. The electrocatalytic behaviour of the NixCo3-xO4 hierarchical nanostructures was compared with the behaviour of Co3O4 and Co0.33Ni0.67O. The synergistic behaviour of the Ni in the NixCo3-xO4 nanostructures was established with respect to the Ni content. NixCo3-xO4 hierarchical nanostructures show a better catalytic behaviour than Co3O4 and Co0.33Ni0.67O. Although the NixCo3-xO4 compositions all showed good catalytic behaviour, Ni1Co2O4 was identified as a superior bifunctional electrocatalyst for the oxygen reduction and methanol oxidation reactions in alkaline media. The effect of the Ni content on the electrocatalytic properties of the NixCo3-xO4 hierarchical nanostructures was clearly shown. The use of these electrocatalysts based on non-precious metals could have a commercial impact on the development of non-platinum electrocatalysts for application in AEM alkaline alcohol fuel cells.Bifunctional electrocatalysts based on non-precious metals were developed for the dioxygen reduction and methanol oxidation reactions. These electrocatalysts can be considered as candidate cathode and anode materials for anion-exchange membrane (AEM) alkaline alcohol fuel cells. A series of Ni-doped cobalt oxide (NixCo3-xO4) hierarchical nanostructures composed of one-dimensional nanorods was prepared by an inexpensive hydrothermal method. X

  6. Cumulative effect of transition metals on nitrogen and fluorine co-doped graphite nanofibers: an efficient and highly durable non-precious metal catalyst for the oxygen reduction reaction.

    PubMed

    Peera, S Gouse; Arunchander, A; Sahu, A K

    2016-08-14

    Nitrogen and fluorine co-doped graphite nanofibers (N/F-GNF) and their cumulative effect with Fe and Co have been developed as an alternative non-precious metal catalyst for efficient oxygen reduction reaction (ORR) in acidic media. The synergistic effect between the doped hetero atoms and the co-ordinated Fe and Co towards ORR activity and durability of the catalyst is deeply investigated. A high ORR onset potential comparable with commercial Pt/C catalyst is observed with the Fe-Co/NF-GNF catalyst, which indicates that this catalyst is a potential alternative to Pt/C. A fivefold increase in mass activity is achieved by the Fe-Co/NF-GNF catalyst compared to the simple N/F-GNF catalyst, which endorses the significant role of transition metal atoms in enhancing ORR activity. The advanced Fe-Co/NF-GNF catalyst also exhibits complete tolerance to CH3OH and CO. The Fe-Co/NF-GNF catalyst also exhibits excellent durability towards the ORR with only a 10 mV negative shift in its half wave potential after a 10 000 repeated potential cycling test, whereas in the case of a commercial Pt/C catalyst there was an ∼110 mV negative shift under similar environmental conditions. More stringent corrosive test cycles were also performed by maintaining the cell as high as 1.4 V with a later decrease to 0.6 V vs. RHE for 300 cycles, which showed the excellent durability of the Fe-Co/NF-GNF catalyst in comparison with the Pt/C catalyst. XPS analysis of the Fe-Co/NF-GNF catalyst presents the ORR active chemical states of N (pyridinic-N and graphitic-N) and F (semi-ionic-F) and the co-ordinated sites of Fe and Co species with the dopants. The excellent performance and durability of the Fe-Co/NF-GNF catalyst is due to the synergistic effect between the hetero atoms dopants (N and F) and strong co-ordinating bonds of M-N-C, which protect the graphene layers around the metallic species and greatly mitigates the leaching of Co and Fe during the long term cycling test. The high activity

  7. Use of urchin-like Ni(x)Co(3-x)O4 hierarchical nanostructures based on non-precious metals as bifunctional electrocatalysts for anion-exchange membrane alkaline alcohol fuel cells.

    PubMed

    Manivasakan, Palanisamy; Ramasamy, Parthiban; Kim, Jinkwon

    2014-08-21

    Bifunctional electrocatalysts based on non-precious metals were developed for the dioxygen reduction and methanol oxidation reactions. These electrocatalysts can be considered as candidate cathode and anode materials for anion-exchange membrane (AEM) alkaline alcohol fuel cells. A series of Ni-doped cobalt oxide (NixCo3-xO4) hierarchical nanostructures composed of one-dimensional nanorods was prepared by an inexpensive hydrothermal method. X-ray diffraction patterns showed that the NixCo3-xO4 crystallized in a cubic spinel phase. The electrochemical performance of the catalysts was investigated using a conventional cyclic voltammetry technique. The electrocatalytic behaviour of the NixCo3-xO4 hierarchical nanostructures was compared with the behaviour of Co3O4 and Co0.33Ni0.67O. The synergistic behaviour of the Ni in the NixCo3-xO4 nanostructures was established with respect to the Ni content. NixCo3-xO4 hierarchical nanostructures show a better catalytic behaviour than Co3O4 and Co0.33Ni0.67O. Although the NixCo3-xO4 compositions all showed good catalytic behaviour, Ni1Co2O4 was identified as a superior bifunctional electrocatalyst for the oxygen reduction and methanol oxidation reactions in alkaline media. The effect of the Ni content on the electrocatalytic properties of the NixCo3-xO4 hierarchical nanostructures was clearly shown. The use of these electrocatalysts based on non-precious metals could have a commercial impact on the development of non-platinum electrocatalysts for application in AEM alkaline alcohol fuel cells. PMID:24990285

  8. Cumulative effect of transition metals on nitrogen and fluorine co-doped graphite nanofibers: an efficient and highly durable non-precious metal catalyst for the oxygen reduction reaction

    NASA Astrophysics Data System (ADS)

    Peera, S. Gouse; Arunchander, A.; Sahu, A. K.

    2016-07-01

    Nitrogen and fluorine co-doped graphite nanofibers (N/F-GNF) and their cumulative effect with Fe and Co have been developed as an alternative non-precious metal catalyst for efficient oxygen reduction reaction (ORR) in acidic media. The synergistic effect between the doped hetero atoms and the co-ordinated Fe and Co towards ORR activity and durability of the catalyst is deeply investigated. A high ORR onset potential comparable with commercial Pt/C catalyst is observed with the Fe-Co/NF-GNF catalyst, which indicates that this catalyst is a potential alternative to Pt/C. A fivefold increase in mass activity is achieved by the Fe-Co/NF-GNF catalyst compared to the simple N/F-GNF catalyst, which endorses the significant role of transition metal atoms in enhancing ORR activity. The advanced Fe-Co/NF-GNF catalyst also exhibits complete tolerance to CH3OH and CO. The Fe-Co/NF-GNF catalyst also exhibits excellent durability towards the ORR with only a 10 mV negative shift in its half wave potential after a 10 000 repeated potential cycling test, whereas in the case of a commercial Pt/C catalyst there was an ~110 mV negative shift under similar environmental conditions. More stringent corrosive test cycles were also performed by maintaining the cell as high as 1.4 V with a later decrease to 0.6 V vs. RHE for 300 cycles, which showed the excellent durability of the Fe-Co/NF-GNF catalyst in comparison with the Pt/C catalyst. XPS analysis of the Fe-Co/NF-GNF catalyst presents the ORR active chemical states of N (pyridinic-N and graphitic-N) and F (semi-ionic-F) and the co-ordinated sites of Fe and Co species with the dopants. The excellent performance and durability of the Fe-Co/NF-GNF catalyst is due to the synergistic effect between the hetero atoms dopants (N and F) and strong co-ordinating bonds of M-N-C, which protect the graphene layers around the metallic species and greatly mitigates the leaching of Co and Fe during the long term cycling test. The high activity and

  9. Cumulative effect of transition metals on nitrogen and fluorine co-doped graphite nanofibers: an efficient and highly durable non-precious metal catalyst for the oxygen reduction reaction

    NASA Astrophysics Data System (ADS)

    Peera, S. Gouse; Arunchander, A.; Sahu, A. K.

    2016-07-01

    Nitrogen and fluorine co-doped graphite nanofibers (N/F-GNF) and their cumulative effect with Fe and Co have been developed as an alternative non-precious metal catalyst for efficient oxygen reduction reaction (ORR) in acidic media. The synergistic effect between the doped hetero atoms and the co-ordinated Fe and Co towards ORR activity and durability of the catalyst is deeply investigated. A high ORR onset potential comparable with commercial Pt/C catalyst is observed with the Fe-Co/NF-GNF catalyst, which indicates that this catalyst is a potential alternative to Pt/C. A fivefold increase in mass activity is achieved by the Fe-Co/NF-GNF catalyst compared to the simple N/F-GNF catalyst, which endorses the significant role of transition metal atoms in enhancing ORR activity. The advanced Fe-Co/NF-GNF catalyst also exhibits complete tolerance to CH3OH and CO. The Fe-Co/NF-GNF catalyst also exhibits excellent durability towards the ORR with only a 10 mV negative shift in its half wave potential after a 10 000 repeated potential cycling test, whereas in the case of a commercial Pt/C catalyst there was an ~110 mV negative shift under similar environmental conditions. More stringent corrosive test cycles were also performed by maintaining the cell as high as 1.4 V with a later decrease to 0.6 V vs. RHE for 300 cycles, which showed the excellent durability of the Fe-Co/NF-GNF catalyst in comparison with the Pt/C catalyst. XPS analysis of the Fe-Co/NF-GNF catalyst presents the ORR active chemical states of N (pyridinic-N and graphitic-N) and F (semi-ionic-F) and the co-ordinated sites of Fe and Co species with the dopants. The excellent performance and durability of the Fe-Co/NF-GNF catalyst is due to the synergistic effect between the hetero atoms dopants (N and F) and strong co-ordinating bonds of M-N-C, which protect the graphene layers around the metallic species and greatly mitigates the leaching of Co and Fe during the long term cycling test. The high activity and

  10. DOE Award No. DE-FC36-03GO13108 NOVEL NON-PRECIOUS METAL CATALYSTS FOR PEMFC: CATALYST SELECTION THROUGH MOLECULAR MODELING AND DURABILITY STUDIES Final Report (September 2003 – October 2008)

    SciTech Connect

    Branko N. Popov

    2009-03-03

    The objective of this project is to develop novel non-precious metal electrocatalysts for oxygen reduction reaction (ORR), and demonstrate the potential of the catalysts to perform at least as good as conventional Pt catalysts currently in use in polymer electrolyte membrane fuel cell (PEMFC) with a cost at least 50 % less than a target of 0.2 g (Pt loading)/peak kW and with durability > 2,000 h operation with less than 10 % power degradation. A novel nitrogen-modified carbon-based catalyst was obtained by modifying carbon black with nitrogen-containing organic precursor in the absence of transition metal precursor. The catalyst shows the onset potential of approximately 0.76 V (NHE) for ORR and the amount of H2O2 of approximately 3% at 0.5 V (NHE). Furthermore, a carbon composite catalyst was achieved through the high-temperature pyrolysis of the precursors of transition metal (Co and Fe) and nitrogen supported on the nitrogen-modified carbon-based catalyst, followed by chemical post-treatment. This catalyst showed an onset potential for ORR as high as 0.87 V (NHE), and generated less than 1 % of H2O2. The PEM fuel cell exhibited a current density of 2.3 A cm-2 at 0.2 V for a catalyst loading of 6.0 mg cm-2. No significant performance degradation was observed for 480 h continuous operation. The characterization studies indicated that the metal-nitrogen chelate complexes decompose at the temperatures above 800 oC. During the pyrolysis, the transition metals facilitate the incorporation of pyridinic and graphitic nitrogen groups into the carbon matrix, and the carbon surface modified with nitrogen is active for ORR. In order to elucidate the role of transition metal precursor played in the formation of active sites in the non-precious metal catalysts, a novel ruthenium-based chelate (RuNx) catalyst was synthesized by using RuCl3 and propylene diammine as the Ru and N precursors, respectively, followed by high-temperature pyrolysis. This catalyst exhibited comparable

  11. DOE Award No. DE-FC36-03GO13108 NOVEL NON-PRECIOUS METAL CATALYSTS FOR PEMFC: CATALYST SELECTION THROUGH MOLECULAR MODELING AND DURABILITY STUDIES Final Report (September 2003 – October 2008)

    SciTech Connect

    Branko N. Popov

    2009-02-20

    The objective of this project is to develop novel non-precious metal electrocatalysts for oxygen reduction reaction (ORR), and demonstrate the potential of the catalysts to perform at least as good as conventional Pt catalysts currently in use in polymer electrolyte membrane fuel cell (PEMFC) with a cost at least 50 % less than a target of 0.2 g (Pt loading)/peak kW and with durability > 2,000 h operation with less than 10 % power degradation. A novel nitrogen-modified carbon-based catalyst was obtained by modifying carbon black with nitrogen-containing organic precursor in the absence of transition metal precursor. The catalyst shows the onset potential of approximately 0.76 V (NHE) for ORR and the amount of H2O2 of approximately 3% at 0.5 V (NHE). Furthermore, a carbon composite catalyst was achieved through the high-temperature pyrolysis of the precursors of transition metal (Co and Fe) and nitrogen supported on the nitrogen-modified carbon-based catalyst, followed by chemical post-treatment. This catalyst showed an onset potential for ORR as high as 0.87 V (NHE), and generated less than 1 % of H2O2. The PEM fuel cell exhibited a current density of 2.3 A cm-2 at 0.2 V for a catalyst loading of 6.0 mg cm-2. No significant performance degradation was observed for 480 h continuous operation. The characterization studies indicated that the metal-nitrogen chelate complexes decompose at the temperatures above 800 oC. During the pyrolysis, the transition metals facilitate the incorporation of pyridinic and graphitic nitrogen groups into the carbon matrix, and the carbon surface modified with nitrogen is active for ORR. In order to elucidate the role of transition metal precursor played in the formation of active sites in the non-precious metal catalysts, a novel ruthenium-based chelate (RuNx) catalyst was synthesized by using RuCl3 and propylene diammine as the Ru and N precursors, respectively, followed by high-temperature pyrolysis. This catalyst exhibited comparable

  12. Accumulation of the precious metals platinum, palladium and rhodium from automobile catalytic converters in Paratenuisentis ambiguus as compared with its fish host, Anguilla anguilla.

    PubMed

    Zimmermann, S; von Bohlen, A; Messerschmidt, J; Sures, B

    2005-03-01

    The platinum group metals (PGM) Pt, Pd and Rh are emitted into the environment mainly by catalytic exhaust gas converters of cars. As PGM accumulate in sediments of aquatic ecosystems, the study was focused on the uptake of the noble metals by European eels, Anguilla anguilla infected with the acanthocephalan Paratenuisentis ambiguus. Eels were exposed to ground catalytic converter material for six weeks. After exposure Pt and Pd were detected in the liver and kidney of the eels and in the parasites. Palladium was also found in fish muscle and intestine. No Rh uptake by the eel tissues and the parasites occurred. Paratenuisentis ambiguus contained the highest levels of both metals with 40 times higher Pt concentrations and four times higher Pd concentrations than the liver of its host. Due to its accumulation capacity for PGM, P. ambiguus can be applied as a sensitive accumulation indicator in field studies to assess the degree of environmental PGM contamination in aquatic ecosystems. PMID:15831118

  13. Mineralogical and geochemical controls on the release of trace elements from slag produced by base- and precious-metal smelting at abandoned mine sites

    USGS Publications Warehouse

    Piatak, N.M.; Seal, R.R., II; Hammarstrom, J.M.

    2004-01-01

    Slag collected from smelter sites associated with historic base-metal mines contains elevated concentrations of trace elements such as Cu, Zn and Pb. Weathering of slag piles, many of which were deposited along stream banks, potentially may release these trace elements into the environment. Slags were sampled from the Ely and Elizabeth mines in the Vermont copper belt, from the copper Basin mining district at Ducktown, Tennessee and from the Clayton silver mine in the Bayhorse mining district, Idaho, in the USA. Primary phases in the slags include: olivine-group minerals, glass, spinels, sulfide minerals and native metals for Vermont samples; glass, sulfide minerals and native metals for the Ducktown sample; and olivine-group minerals, clinopyroxenes, spinels, sulfide minerals, native metals and other unidentified metallic compounds for Clayton slag. Olivine-group minerals and pyroxenes are dominantly fayalitic and hedenbergitic in composition, respectively and contain up to 1.25 wt.% ZnO. Spinel minerals range between magnetite and hercynite in composition and contain Zn (up to 2.07 wt.% ZnO), Ti (up to 4.25 wt.% TiO2) and Cr (up to 1.39 wt.% Cr2O3). Cobalt, Ni, Cu, As, Ag, Sb and Pb occur in the glass phase, sulfides, metallic phases and unidentified metallic compounds. Bulk slag trace-element chemistry shows that the metals of the Vermont and Tennessee slags are dominated by Cu (1900-13,500 mg/kg) and Zn (2310-10,200 mg/kg), whereas the Clayton slag is dominated by Pb (63,000 mg/kg), Zn (19,700 mg/kg), Cu (7550 mg/kg), As (555 mg/kg), Sn (363 mg/kg) and Ag (200 mg/kg). Laboratory-based leach tests indicate metals can be released under simulated natural conditions. Leachates from most slags were found to contain elevated concentrations of Cu and Zn (up to 1800 and 470 ??g/l, respectively), well in excess of the acute toxicity guidelines for aquatic life. For the Idaho slag, the concentration of Pb in the leachate (11,000 ??g/l) is also in excess of the acute

  14. Comparative anatomy of epithermal precious- and base-metal districts hosted by volcanic rocks: A talk presented at the GAC/MSC/GGU Joint Annual Meeting, May 11-13, 1983, Victoria, British Columbia

    USGS Publications Warehouse

    Heald-Wetlaufer, Pamela; Hayba, Daniel O.; Foley, Nora K.; Goss, J.A.

    1983-01-01

    In order to distinguish dissimilar from similar features of epithermal districts, lithotectonic, mineralogical and geochemical traits are compiled for 15 such districts. The districts occur in structurally complex settings associated with silicic to intermediate volcanics. Affiliation with subduction environments on a continental scale and caldera settings on a regional scale is common but is not demonstrable for all districts. Most deposits formed near the end of major volcanism, but some formed considerably later. Paleodepth to the top of the ore is 300-600m for most districts, although Au-rich districts appear to be shallower. The lateral extent of the ore zone is highly variable and far exceeds the limited vertical range (300-800m). Most ore was deposited from dominantly meteoric fluids ranging in temperature from 220°-290°C. Salinities ranged from 0-13 wt% NaCl equiv., and typical values were 1-3 wt%. Although noted for eight deposits, boiling is clearly associated with precious-metal deposition in only two deposits. Four districts, typified by Goldfield, Nev., are characterized by a highly sulfidized mineral assemblage, advanced argillic alteration, and ore deposition closely following emplacement of the host rock. The remaining eleven districts highlight a second, discrete type of deposit. They contain adularia, exhibit sericitic ± argillic alteration, and were mineralized significantly after emplacement of the host rock. The latter category includes two subgroups: Ag- and base-metal-rich deposits (e.g., Creede, Colo.), and Au-rich, base-metal-poor deposits (e.g., Round Mtn., Nev.).

  15. Enzyme leaching of surficial geochemical samples for detecting hydromorphic trace-element anomalies associated with precious-metal mineralized bedrock buried beneath glacial overburden in northern Minnesota

    USGS Publications Warehouse

    Clark, Robert J.; Meier, A.L.; Riddle, G.

    1990-01-01

    One objective of the International Falls and Roseau, Minnesota, CUSMAP projects was to develop a means of conducting regional-scale geochemical surveys in areas where bedrock is buried beneath complex glacially derived overburden. Partial analysis of B-horizon soils offered hope for detecting subtle hydromorphic trace-element dispersion patterns. An enzyme-based partial leach selectively removes metals from oxide coatings on the surfaces of soil materials without attacking their matrix. Most trace-element concentrations in the resulting solutions are in the part-per-trillion to low part-per-billion range, necessitating determinations by inductively coupled plasma/mass spectrometry. The resulting data show greater contrasts for many trace elements than with other techniques tested. Spatially, many trace metal anomalies are locally discontinuous, but anomalous trends within larger areas are apparent. In many instances, the source for an anomaly seems to be either basal till or bedrock. Ground water flow is probably the most important mechanism for transporting metals toward the surface, although ionic diffusion, electrochemical gradients, and capillary action may play a role in anomaly dispersal. Sample sites near the Rainy Lake-Seine River fault zone, a regional shear zone, often have anomalous concentrations of a variety of metals, commonly including Zn and/or one or more metals which substitute for Zn in sphalerite (Cd, Ge, Ga, and Sn). Shifts in background concentrations of Bi, Sb, and As show a trend across the area indicating a possible regional zoning of lode-Au mineralization. Soil anomalies of Ag, Co, and Tl parallel basement structures, suggesting areas that may have potential for Cobalt/Thunder Baytype silver viens. An area around Baudette, Minnesota, which is underlain by quartz-chlorite-carbonate-altered shear zones, is anomalous in Ag, As, Bi, Co, Mo, Te, Tl, and W. Anomalies of Ag, As, Bi, Te, and W tend to follow the fault zones, suggesting potential

  16. Surface-Specific Nucleation and Deposition (?) of Heavy and Precious Metals on Minerals and Fibers Exposed to Fumarole Gas - FESEM/EDS Studies

    NASA Astrophysics Data System (ADS)

    Obenholzner, J. H.; Poelt, P.; Reichmann, A.

    2004-12-01

    Mineral grains, glass fibers and diatoms had been exposed to the F0 fumarole at Vulcano (Italy) between 2001 and 2004. On quartz grains patches of Pb-(Tl)-Cl (max.l=50 µm), Tl-(Fe)-(Br)-Cl, Al-S-Cl-(O), Al-Cl-(F)-(S)-(Mg)-(K)-(Ca)-(Fe) and needle-like Ca sulphate (+Cl-F) are growing. Pb-S nucleated on K feldspar, Ba-S-O and As-S on the surface of diatoms. Desert dust interacting with volcanic gases might transport heavy metals to environments far away from volcanoes. Si-rich glass fibers are the substratum for Tl-Cl, Hg-, As-, Tl- and Pb-bearing and Al-(S)-(O) crystals. Au-Ag alloys (l= ca. 3 µm) are detected on Si-rich fibers. These anhedral grains are embedded in an Al-O-(S)-(Ca) matrix. Available data do not indicate if deposition or nucleation are the responsible processes. Ba-S-O particles nucleated on borosilicate glass fibers. Rock wool of basaltic composition (Na-Mg-Al-Si-K-Ca-Ti-Fe-O) collected only S and shows surface modification. These preliminary results indicate that Si-rich surfaces might be useful in i.e. air conditioning systems to detoxicate volcanically polluted air. Quartz sand deployed on top of lava flows might reduce the release of heavy metals to the environment. According to the experiments utilizing glass fibers of different composition the eruptions of basaltic magma should release more heavy metals to the atmosphere relatively compared to the eruptions of rhyolitic magma.

  17. Precious-metal-free Co-Fe-O/rGO synergetic electrocatalysts for oxygen evolution reaction by a facile hydrothermal route.

    PubMed

    Geng, Jing; Kuai, Long; Kan, Erjie; Wang, Qing; Geng, Baoyou

    2015-02-01

    Abundant iron group metal oxides and their composites possess great potential in the application of electrochemical energy storage and conversion. In this work, we obtained Co-Fe-O composites/reduced graphene oxides (CFO/rGO) hybrid structures, engineered their compositions, phase, and structures by a facile hydrothermal route, and studied their composition-dependent activity for electrochemical oxygen evolution reaction (OER) in alkaline media. It is found that synergetic effects bring a clear decrease in overpotential and Tafel slope for CFO/rGO catalysts in comparison with monometallic composition/rGO catalysts. OER charge-transfer resistance is significantly reduced after Fe addition, indicating that the reaction barriers of CFO/rGO are reduced. The optimal CFO/rGO with Co-Fe ratio of 2:1 was identified. Our results on the synergetic effects of CFO/rGO enrich the understanding of iron-group composites for electrocatalytic applications. PMID:25572639

  18. Simulation of substrate erosion and sulphate assimilation by Martian low-viscosity lava flows: implications for the genesis of precious metal-rich sulphide mineralisation on Mars

    NASA Astrophysics Data System (ADS)

    Baumgartner, Raphael; Baratoux, David; Gaillard, Fabrice; Fiorentini, Marco

    2016-04-01

    On Earth, high temperature mafic to ultramafic lava flows, such as komatiites and ferropicrites of the Archean and Proterozic eons, can be hosts to Ni-Cu-PGE sulphide mineralisation. Mechanical/thermo-mechanical erosion and assimilation of sulphur-rich crustal rocks is ascribed as the principal mechanism that leads to sulphide supersaturation, batch segregation and subsequent accumulation of metal-enriched magmatic sulphides (e.g., Bekker et al., Science, 2009). In order to investigate the likelihood of the occurrence of similar sulphide mineralisation in extraterrestrial magmatic systems, we numerically modelled erosion and assimilation during the turbulent emplacement of Martian lavas, some of which display chemical and rheological analogies with terrestrial komatiites and ferropicrites, on a variety of consolidated sedimentary sulphate-rich substrates. The modelling approach relies on the integration of i) mathematical lava erosion models for turbulent flows (Williams et al., J. Geophys. Res., 1998), ii) thermodynamic volatile degassing models (Gaillard et al., Space Sci. Rev., 2013), and iii) formulations on the stability of sulphides (Fortin et al., Geochim. Cosmochim. Acta, 2015). A series of scenarios are examined in which various Martian mafic to ultramafic mantle-derived melts emplace over, and assimilate consolidated sulphate-rich substrates, such as the sedimentary lithologies (i.e., conglomerates, sandstones and mudstones) recently discovered at the Gale Crater landing site. Our modellings show that lavas emplacing over consolidated sedimentary substrate rather than stiff basaltic crust, are governed by relatively high cooling and substrate erosion rates. The rapid assimilation of sulphate, which serves as a strongly oxidising agent, could result in dramatic sulphur loss due to increased volatile degassing rates at fO2 ≳QFM-1. This effect is further enhanced with increased temperature. Nevertheless, sulphide supersaturation in the way of sulphate

  19. 50 CFR 665.260 - Hawaii precious coral fisheries. [Reserved

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Hawaii precious coral fisheries. 665.260 Section 665.260 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND... Fisheries § 665.260 Hawaii precious coral fisheries....

  20. 50 CFR 665.260 - Hawaii precious coral fisheries. [Reserved

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 13 2014-10-01 2014-10-01 false Hawaii precious coral fisheries. 665.260 Section 665.260 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND... Fisheries § 665.260 Hawaii precious coral fisheries....

  1. 50 CFR 665.660 - PRIA precious coral fisheries. [Reserved

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false PRIA precious coral fisheries. 665.660 Section 665.660 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND... Island Area Fisheries § 665.660 PRIA precious coral fisheries....

  2. 50 CFR 665.660 - PRIA precious coral fisheries. [Reserved

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 13 2014-10-01 2014-10-01 false PRIA precious coral fisheries. 665.660 Section 665.660 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND... Island Area Fisheries § 665.660 PRIA precious coral fisheries....

  3. 50 CFR 665.460 - Mariana precious coral fisheries. [Reserved

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Mariana precious coral fisheries. 665.460 Section 665.460 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND... Archipelago Fisheries § 665.460 Mariana precious coral fisheries....

  4. 50 CFR 665.460 - Mariana precious coral fisheries. [Reserved

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 13 2014-10-01 2014-10-01 false Mariana precious coral fisheries. 665.460 Section 665.460 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND... Archipelago Fisheries § 665.460 Mariana precious coral fisheries....

  5. 16 CFR 23.24 - Misuse of the words “real,” “genuine,” “natural,” “precious,” etc.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Misuse of the words âreal,â âgenuine,â ânatural,â âprecious,â etc. 23.24 Section 23.24 Commercial Practices FEDERAL TRADE COMMISSION GUIDES AND TRADE PRACTICE RULES GUIDES FOR THE JEWELRY, PRECIOUS METALS, AND PEWTER INDUSTRIES § 23.24 Misuse...

  6. 16 CFR 23.24 - Misuse of the words “real,” “genuine,” “natural,” “precious,” etc.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 16 Commercial Practices 1 2011-01-01 2011-01-01 false Misuse of the words âreal,â âgenuine,â ânatural,â âprecious,â etc. 23.24 Section 23.24 Commercial Practices FEDERAL TRADE COMMISSION GUIDES AND TRADE PRACTICE RULES GUIDES FOR THE JEWELRY, PRECIOUS METALS, AND PEWTER INDUSTRIES § 23.24 Misuse...

  7. 16 CFR 23.24 - Misuse of the words “real,” “genuine,” “natural,” “precious,” etc.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 16 Commercial Practices 1 2014-01-01 2014-01-01 false Misuse of the words âreal,â âgenuine,â ânatural,â âprecious,â etc. 23.24 Section 23.24 Commercial Practices FEDERAL TRADE COMMISSION GUIDES AND TRADE PRACTICE RULES GUIDES FOR THE JEWELRY, PRECIOUS METALS, AND PEWTER INDUSTRIES § 23.24 Misuse...

  8. 16 CFR 23.24 - Misuse of the words “real,” “genuine,” “natural,” “precious,” etc.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 16 Commercial Practices 1 2013-01-01 2013-01-01 false Misuse of the words âreal,â âgenuine,â ânatural,â âprecious,â etc. 23.24 Section 23.24 Commercial Practices FEDERAL TRADE COMMISSION GUIDES AND TRADE PRACTICE RULES GUIDES FOR THE JEWELRY, PRECIOUS METALS, AND PEWTER INDUSTRIES § 23.24 Misuse...

  9. 16 CFR 23.24 - Misuse of the words “real,” “genuine,” “natural,” “precious,” etc.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 16 Commercial Practices 1 2012-01-01 2012-01-01 false Misuse of the words âreal,â âgenuine,â ânatural,â âprecious,â etc. 23.24 Section 23.24 Commercial Practices FEDERAL TRADE COMMISSION GUIDES AND TRADE PRACTICE RULES GUIDES FOR THE JEWELRY, PRECIOUS METALS, AND PEWTER INDUSTRIES § 23.24 Misuse...

  10. GOLD NANOPARTICLES: A REVIVAL IN PRECIOUS METAL ADMINISTRATION TO PATIENTS

    PubMed Central

    Thakor, AS; Jokerst, J; Zaveleta, C; Massoud, TF; Gambhir, SS

    2011-01-01

    Gold has been used as a therapeutic agent to treat a wide variety of rheumatic diseases including psoriatic arthritis, juvenile arthritis and discoid lupus erythematosus. Although the use of gold has been largely superseded by newer drugs, gold nanoparticles are being used effectively in laboratory based clinical diagnostic methods whilst concurrently showing great promise in vivo either as a diagnostic imaging agent or a therapeutic agent. For these reasons, gold nanoparticles are therefore well placed to enter mainstream clinical practice in the near future. Hence, the present review summarizes the chemistry, pharmacokinetics, bio-distribution, metabolism and toxicity of bulk gold in humans based on decades of clinical observation and experiments in which gold was used to treat patients with rheumatoid arthritis. The beneficial attributes of gold nanoparticles, such as their ease of synthesis, functionalization and shape control are also highlighted demonstrating why gold nanoparticles are an attractive target for further development and optimization. The importance of controlling the size and shape of gold nanoparticles to minimize any potential toxic side effects is also discussed. PMID:21846107

  11. 50 CFR 665.660 - PRIA precious coral fisheries. [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false PRIA precious coral fisheries. 665.660 Section 665.660 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE (CONTINUED) FISHERIES IN THE WESTERN PACIFIC Pacific...

  12. 50 CFR 665.260 - Hawaii precious coral fisheries. [Reserved

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Hawaii precious coral fisheries. 665.260 Section 665.260 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE (CONTINUED) FISHERIES IN THE WESTERN PACIFIC...

  13. 50 CFR 665.260 - Hawaii precious coral fisheries. [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Hawaii precious coral fisheries. 665.260 Section 665.260 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE (CONTINUED) FISHERIES IN THE WESTERN PACIFIC...

  14. 50 CFR 665.660 - PRIA precious coral fisheries. [Reserved

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false PRIA precious coral fisheries. 665.660 Section 665.660 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE (CONTINUED) FISHERIES IN THE WESTERN PACIFIC Pacific...

  15. 50 CFR 665.460 - Mariana precious coral fisheries. [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Mariana precious coral fisheries. 665.460 Section 665.460 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE (CONTINUED) FISHERIES IN THE WESTERN PACIFIC...

  16. 50 CFR 665.660 - PRIA precious coral fisheries. [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false PRIA precious coral fisheries. 665.660 Section 665.660 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE (CONTINUED) FISHERIES IN THE WESTERN PACIFIC Pacific...

  17. 50 CFR 665.460 - Mariana precious coral fisheries. [Reserved

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Mariana precious coral fisheries. 665.460 Section 665.460 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE (CONTINUED) FISHERIES IN THE WESTERN PACIFIC...

  18. 50 CFR 665.260 - Hawaii precious coral fisheries. [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false Hawaii precious coral fisheries. 665.260 Section 665.260 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE (CONTINUED) FISHERIES IN THE WESTERN PACIFIC...

  19. 50 CFR 665.460 - Mariana precious coral fisheries. [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false Mariana precious coral fisheries. 665.460 Section 665.460 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE (CONTINUED) FISHERIES IN THE WESTERN PACIFIC...

  20. Mineral resource of the month: platinum-group metals

    USGS Publications Warehouse

    Hilliard, Henry

    2003-01-01

    The precious metals commonly referred to as platinum-group metals (PGM) include iridium, osmium, palladium, platinum, rhodium and ruthenium. PGM are among the rarest of elements, and their market values — particularly for palladium, platinum and rhodium — are the highest of all precious metals.

  1. Hydrogel-derived non-precious electrocatalysts for efficient oxygen reduction

    NASA Astrophysics Data System (ADS)

    You, Bo; Yin, Peiqun; Zhang, Junli; He, Daping; Chen, Gaoli; Kang, Fei; Wang, Huiqiao; Deng, Zhaoxiang; Li, Yadong

    2015-07-01

    The development of highly active, cheap and robust oxygen reduction reaction (ORR) electrocatalysts to replace precious metal platinum is extremely urgent and challenging for renewable energy devices. Herein we report a novel, green and especially facile hydrogel strategy to construct N and B co-doped nanocarbon embedded with Co-based nanoparticles as an efficient non-precious ORR catalyst. The agarose hydrogel provides a general host matrix to achieve a homogeneous distribution of key precursory components including cobalt (II) acetate and buffer salts, which, upon freeze-drying and carbonization, produces the highly active ORR catalyst. The gel buffer containing Tris base, boric acid and ethylenediaminetetraacetic acid, commonly adopted for pH and ionic strength control, plays distinctively different roles here. These include a green precursor for N- and B-doping, a salt porogen and a Co2+ chelating agent, all contributing to the excellent ORR activity. This hydrogel-based process is potentially generalizable for many other catalytic materials.

  2. Polyaniline-derived non-precious catalyst for the polymer electrolyte fuel cathode

    SciTech Connect

    Wu, Gang; Chen, Zhongwei; Garzon, Fernando; Zelenay, Piotr

    2008-01-01

    A novel polyaniline (PANI)-derived non-precious cathode catalyst was developed in this work, exhibiting remarkable activity (onset potential: 0.9 V, half-wave potential: 0.77 V) and selectivity (0.4 % H20 2 at 0.4 V). As a result, the generated current densities at high voltages associated with electrochemically kinetic activity can be achieved to 0.04 Acm-2 for 0.80V and 0.21 Acm-2 for 0.6 V, when air was used in fuel cell tests. MEA life test at a constant voltage of 0.4 V demonstrated a promising stability up to 450 hours, without obvious degradation. The current density during the test was measured around 0.32 A cm-2, a respectable performance for a cell with non-precious cathode, operated on air rather than oxygen. The possible active sites, related to pyridine- and pyrrole-like metal species were discussed according to presented XPS and XRD analysis.

  3. Hydrogel-derived non-precious electrocatalysts for efficient oxygen reduction

    PubMed Central

    You, Bo; Yin, Peiqun; Zhang, Junli; He, Daping; Chen, Gaoli; Kang, Fei; Wang, Huiqiao; Deng, Zhaoxiang; Li, Yadong

    2015-01-01

    The development of highly active, cheap and robust oxygen reduction reaction (ORR) electrocatalysts to replace precious metal platinum is extremely urgent and challenging for renewable energy devices. Herein we report a novel, green and especially facile hydrogel strategy to construct N and B co-doped nanocarbon embedded with Co-based nanoparticles as an efficient non-precious ORR catalyst. The agarose hydrogel provides a general host matrix to achieve a homogeneous distribution of key precursory components including cobalt (II) acetate and buffer salts, which, upon freeze-drying and carbonization, produces the highly active ORR catalyst. The gel buffer containing Tris base, boric acid and ethylenediaminetetraacetic acid, commonly adopted for pH and ionic strength control, plays distinctively different roles here. These include a green precursor for N- and B-doping, a salt porogen and a Co2+ chelating agent, all contributing to the excellent ORR activity. This hydrogel-based process is potentially generalizable for many other catalytic materials. PMID:26130371

  4. Hydrogel-derived non-precious electrocatalysts for efficient oxygen reduction.

    PubMed

    You, Bo; Yin, Peiqun; Zhang, Junli; He, Daping; Chen, Gaoli; Kang, Fei; Wang, Huiqiao; Deng, Zhaoxiang; Li, Yadong

    2015-01-01

    The development of highly active, cheap and robust oxygen reduction reaction (ORR) electrocatalysts to replace precious metal platinum is extremely urgent and challenging for renewable energy devices. Herein we report a novel, green and especially facile hydrogel strategy to construct N and B co-doped nanocarbon embedded with Co-based nanoparticles as an efficient non-precious ORR catalyst. The agarose hydrogel provides a general host matrix to achieve a homogeneous distribution of key precursory components including cobalt (II) acetate and buffer salts, which, upon freeze-drying and carbonization, produces the highly active ORR catalyst. The gel buffer containing Tris base, boric acid and ethylenediaminetetraacetic acid, commonly adopted for pH and ionic strength control, plays distinctively different roles here. These include a green precursor for N- and B-doping, a salt porogen and a Co(2+) chelating agent, all contributing to the excellent ORR activity. This hydrogel-based process is potentially generalizable for many other catalytic materials. PMID:26130371

  5. Summary of Dissimilar Metal Joining Trials Conducted by Edison Welding Institute

    SciTech Connect

    MJ Lambert

    2005-11-18

    Under the direction of the NASA-Glenn Research Center, the Edison Welding Institute (EWI) in Columbus, OH performed a series of non-fusion joining experiments to determine the feasibility of joining refractory metals or refractory metal alloys to Ni-based superalloys. Results, as reported by EWI, can be found in the project report for EWI Project 48819GTH (Attachment A, at the end of this document), dated October 10, 2005. The three joining methods used in this investigation were inertia welding, magnetic pulse welding, and electro-spark deposition joining. Five materials were used in these experiments: Mo-47Re, T-111, Hastelloy X, Mar M-247 (coarse-grained, 0.5 mm to several millimeter average grain size), and Mar M-247 (fine-grained, approximately 50 {micro}m average grain size). Several iterative trials of each material combination with each joining method were performed to determine the best practice joining method. Mo-47Re was found to be joined easily to Hastelloy X via inertia welding, but inertia welding of the Mo-alloy to both Mar M-247 alloys resulted in inconsistent joint strength and large reaction layers between the two metals. T-111 was found to join well to Hastelloy X and coarse-grained Mar M-247 via inertia welding, but joining to fine-grained Mar M-247 resulted in low joint strength. Magnetic pulse welding (MPW) was only successful in joining T-111 tubing to Hastelloy X bar stock. The joint integrity and reaction layer between the metals were found to be acceptable. This single joining trial, however, caused damage to the electromagnetic concentrators used in this process. Subsequent design efforts to eliminate the problem resulted in a loss of power imparted to the accelerating work piece, and results could not be reproduced. Welding trials of Mar M-247 to T-111 resulted in catastrophic failure of the bar stock, even at lower power. Electro-spark deposition joining of Mo-47Re, in which the deposited material was Hastelloy X, did not have a

  6. 31 CFR 1027.210 - Anti-money laundering programs for dealers in precious metals, precious stones, or jewels.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... program must be approved by senior management. A dealer shall make its anti-money laundering program... upon the dealer's assessment of the money laundering and terrorist financing risks associated with its... Secrecy Act (31 U.S.C. 5311 et seq.), and this chapter. (i) For purposes of making the risk...

  7. 31 CFR 1027.210 - Anti-money laundering programs for dealers in precious metals, precious stones, or jewels.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... program must be approved by senior management. A dealer shall make its anti-money laundering program... upon the dealer's assessment of the money laundering and terrorist financing risks associated with its... Secrecy Act (31 U.S.C. 5311 et seq.), and this chapter. (i) For purposes of making the risk...

  8. 31 CFR 1027.210 - Anti-money laundering programs for dealers in precious metals, precious stones, or jewels.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Secrecy Act (31 U.S.C. 5311 et seq.), and this chapter. (i) For purposes of making the risk assessment... scope and frequency of the testing shall be commensurate with the risk assessment conducted by the...; (ii) The anti-money laundering program is updated as necessary to reflect changes in the...

  9. 31 CFR 1027.210 - Anti-money laundering programs for dealers in precious metals, precious stones, or jewels.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Secrecy Act (31 U.S.C. 5311 et seq.), and this chapter. (i) For purposes of making the risk assessment... scope and frequency of the testing shall be commensurate with the risk assessment conducted by the...; (ii) The anti-money laundering program is updated as necessary to reflect changes in the...

  10. 31 CFR 103.140 - Anti-money laundering programs for dealers in precious metals, precious stones, or jewels.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... to provide complete or accurate contact information, financial references, or business affiliations...: Treasury Regulations Relating to Money and Finance FINANCIAL RECORDKEEPING AND REPORTING OF CURRENCY AND... been identified by the Department of State as a sponsor of international terrorism under 22 U.S.C....

  11. 78 FR 33064 - Silicon Metal From Russia; Institution of a Five-Year Review

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-03

    ... order on imports of silicon metal from Russia (68 FR 14578). Following the five-year reviews by Commerce... order on imports of silicon metal from Russia (73 FR 40848). The Commission is now conducting a second...) (19 CFR 201.15(b)), 73 FR 24609 (May 5, 2008). This advice was developed in consultation with...

  12. 50 CFR 665.160 - American Samoa precious coral fisheries. [Reserved

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 13 2014-10-01 2014-10-01 false American Samoa precious coral fisheries. 665.160 Section 665.160 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC... American Samoa Fisheries § 665.160 American Samoa precious coral fisheries....

  13. 50 CFR 665.160 - American Samoa precious coral fisheries. [Reserved

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false American Samoa precious coral fisheries. 665.160 Section 665.160 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC... American Samoa Fisheries § 665.160 American Samoa precious coral fisheries....

  14. Cobalt/copper-decorated carbon nanofibers as novel non-precious electrocatalyst for methanol electrooxidation

    NASA Astrophysics Data System (ADS)

    Barakat, Nasser A. M.; El-Newehy, Mohamed; Al-Deyab, Salem S.; Kim, Hak Yong

    2014-01-01

    In this study, Co/Cu-decorated carbon nanofibers are introduced as novel electrocatalyst for methanol oxidation. The introduced nanofibers have been prepared based on graphitization of poly(vinyl alcohol) which has high carbon content compared to many polymer precursors for carbon nanofiber synthesis. Typically, calcination in argon atmosphere of electrospun nanofibers composed of cobalt acetate tetrahydrate, copper acetate monohydrate, and poly(vinyl alcohol) leads to form carbon nanofibers decorated by CoCu nanoparticles. The graphitization of the poly(vinyl alcohol) has been enhanced due to presence of cobalt which acts as effective catalyst. The physicochemical characterization affirmed that the metallic nanoparticles are sheathed by thin crystalline graphite layer. Investigation of the electrocatalytic activity of the introduced nanofibers toward methanol oxidation indicates good performance, as the corresponding onset potential was small compared to many reported materials; 310 mV (vs. Ag/AgCl electrode) and a current density of 12 mA/cm2 was obtained. Moreover, due to the graphite shield, good stability was observed. Overall, the introduced study opens new avenue for cheap and stable transition metals-based nanostructures as non-precious catalysts for fuel cell applications.

  15. Cobalt/copper-decorated carbon nanofibers as novel non-precious electrocatalyst for methanol electrooxidation

    PubMed Central

    2014-01-01

    In this study, Co/Cu-decorated carbon nanofibers are introduced as novel electrocatalyst for methanol oxidation. The introduced nanofibers have been prepared based on graphitization of poly(vinyl alcohol) which has high carbon content compared to many polymer precursors for carbon nanofiber synthesis. Typically, calcination in argon atmosphere of electrospun nanofibers composed of cobalt acetate tetrahydrate, copper acetate monohydrate, and poly(vinyl alcohol) leads to form carbon nanofibers decorated by CoCu nanoparticles. The graphitization of the poly(vinyl alcohol) has been enhanced due to presence of cobalt which acts as effective catalyst. The physicochemical characterization affirmed that the metallic nanoparticles are sheathed by thin crystalline graphite layer. Investigation of the electrocatalytic activity of the introduced nanofibers toward methanol oxidation indicates good performance, as the corresponding onset potential was small compared to many reported materials; 310 mV (vs. Ag/AgCl electrode) and a current density of 12 mA/cm2 was obtained. Moreover, due to the graphite shield, good stability was observed. Overall, the introduced study opens new avenue for cheap and stable transition metals-based nanostructures as non-precious catalysts for fuel cell applications. PMID:24387682

  16. Zinc: A precious trace element for oral health care?

    PubMed

    Fatima, Tayyaba; Haji Abdul Rahim, Zubaidah Binti; Lin, Chai Wen; Qamar, Zeeshan

    2016-08-01

    This review will discuss the importance of Zinc in the maintenance of oral health. Zinc (Zn) is a trace element of valuable importance. In the oral cavity, it is naturally present at various sites such as dental plaque, dental hard tissues and saliva. It is proven to be effective against common prevalent oral health problems such as dental caries, gingivitis, periodontitis and malodour. It is being used in various oral health care products to control the formation of dental plaque and inhibiting the formation of dental calculus. It has the potential to sustain and maintain its elevated concentrations for a longer time particularly in the dental plaque and saliva on delivery from the mouth rinses and toothpastes. It has been reported that low concentrations of zinc have the capability to reduce dissolution and promote remineralization under caries simulating conditions. Most importantly low Zn2+ levels in the serum are useful as a tumour marker. Thus taking a note of its potentials, it can be concluded that zinc is a precious element for the maintenance of oral health. PMID:27524540

  17. Size control of noble metal clusters and metallic heterostructures through the reduction kinetics of metal precursors

    NASA Astrophysics Data System (ADS)

    Sevonkaev, Igor V.; Herein, Daniel; Jeske, Gerald; Goia, Dan V.

    2014-07-01

    Eight precious metal salts/complexes were reduced in propylene glycol at temperatures ranging between 110 and 170 °C. We found that the reduction temperature and the size of precipitated metallic nanoparticles formed were significantly affected by the structure and reactivity of the metal precursors. The choice of noble metal precursor offers flexibility for designing, fabricating and controlling the size of metallic heterostructures with tunable properties.Eight precious metal salts/complexes were reduced in propylene glycol at temperatures ranging between 110 and 170 °C. We found that the reduction temperature and the size of precipitated metallic nanoparticles formed were significantly affected by the structure and reactivity of the metal precursors. The choice of noble metal precursor offers flexibility for designing, fabricating and controlling the size of metallic heterostructures with tunable properties. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr03045a

  18. Highly porous non-precious bimetallic electrocatalysts for efficient hydrogen evolution

    SciTech Connect

    Lu, Qi; Hutchings, Gregory S.; Yu, Weiting; Zhou, Yang; Forest, Robert V.; Tao, Runzhe; Rosen, Jonathan; Yonemoto, Bryan T.; Cao, Zeyuan; Zheng, Haimei; Xiao, John Q.; Jiao, Feng; Chen, Jingguang G.

    2015-03-16

    One of the key components of carbon dioxide-free hydrogen production is a robust and efficient non-precious metal catalyst for the hydrogen evolution reaction. We report that a hierarchical nanoporous copper-titanium bimetallic electrocatalyst is able to produce hydrogen from water under a mild overpotential at more than twice the rate of state-of-the- art carbon-supported platinum catalyst. Although both copper and titanium are known to be poor hydrogen evolution catalysts, the combination of these two elements creates unique copper-copper-titanium hollow sites, which have a hydrogen-binding energy very similar to that of platinum, resulting in an exceptional hydrogen evolution activity. Moreover, the hierarchical porosity of the nanoporous-copper titanium catalyst also contributes to its high hydrogen evolution activity, because it provides a large-surface area for electrocatalytic hydrogen evolution, and improves the mass transport properties. Moreover, the catalyst is self-supported, eliminating the overpotential associated with the catalyst/support interface.

  19. Highly porous non-precious bimetallic electrocatalysts for efficient hydrogen evolution

    PubMed Central

    Lu, Qi; Hutchings, Gregory S.; Yu, Weiting; Zhou, Yang; Forest, Robert V.; Tao, Runzhe; Rosen, Jonathan; Yonemoto, Bryan T.; Cao, Zeyuan; Zheng, Haimei; Xiao, John Q.; Jiao, Feng; Chen, Jingguang G.

    2015-01-01

    A robust and efficient non-precious metal catalyst for hydrogen evolution reaction is one of the key components for carbon dioxide-free hydrogen production. Here we report that a hierarchical nanoporous copper-titanium bimetallic electrocatalyst is able to produce hydrogen from water under a mild overpotential at more than twice the rate of state-of-the-art carbon-supported platinum catalyst. Although both copper and titanium are known to be poor hydrogen evolution catalysts, the combination of these two elements creates unique copper-copper-titanium hollow sites, which have a hydrogen-binding energy very similar to that of platinum, resulting in an exceptional hydrogen evolution activity. In addition, the hierarchical porosity of the nanoporous copper-titanium catalyst also contributes to its high hydrogen evolution activity, because it provides a large-surface area for electrocatalytic hydrogen evolution, and improves the mass transport properties. Moreover, the catalyst is self-supported, eliminating the overpotential associated with the catalyst/support interface. PMID:25910892

  20. Highly porous non-precious bimetallic electrocatalysts for efficient hydrogen evolution

    DOE PAGESBeta

    Lu, Qi; Hutchings, Gregory S.; Yu, Weiting; Zhou, Yang; Forest, Robert V.; Tao, Runzhe; Rosen, Jonathan; Yonemoto, Bryan T.; Cao, Zeyuan; Zheng, Haimei; et al

    2015-03-16

    One of the key components of carbon dioxide-free hydrogen production is a robust and efficient non-precious metal catalyst for the hydrogen evolution reaction. We report that a hierarchical nanoporous copper-titanium bimetallic electrocatalyst is able to produce hydrogen from water under a mild overpotential at more than twice the rate of state-of-the- art carbon-supported platinum catalyst. Although both copper and titanium are known to be poor hydrogen evolution catalysts, the combination of these two elements creates unique copper-copper-titanium hollow sites, which have a hydrogen-binding energy very similar to that of platinum, resulting in an exceptional hydrogen evolution activity. Moreover, the hierarchicalmore » porosity of the nanoporous-copper titanium catalyst also contributes to its high hydrogen evolution activity, because it provides a large-surface area for electrocatalytic hydrogen evolution, and improves the mass transport properties. Moreover, the catalyst is self-supported, eliminating the overpotential associated with the catalyst/support interface.« less

  1. Highly porous non-precious bimetallic electrocatalysts for efficient hydrogen evolution.

    PubMed

    Lu, Qi; Hutchings, Gregory S; Yu, Weiting; Zhou, Yang; Forest, Robert V; Tao, Runzhe; Rosen, Jonathan; Yonemoto, Bryan T; Cao, Zeyuan; Zheng, Haimei; Xiao, John Q; Jiao, Feng; Chen, Jingguang G

    2015-01-01

    A robust and efficient non-precious metal catalyst for hydrogen evolution reaction is one of the key components for carbon dioxide-free hydrogen production. Here we report that a hierarchical nanoporous copper-titanium bimetallic electrocatalyst is able to produce hydrogen from water under a mild overpotential at more than twice the rate of state-of-the-art carbon-supported platinum catalyst. Although both copper and titanium are known to be poor hydrogen evolution catalysts, the combination of these two elements creates unique copper-copper-titanium hollow sites, which have a hydrogen-binding energy very similar to that of platinum, resulting in an exceptional hydrogen evolution activity. In addition, the hierarchical porosity of the nanoporous copper-titanium catalyst also contributes to its high hydrogen evolution activity, because it provides a large-surface area for electrocatalytic hydrogen evolution, and improves the mass transport properties. Moreover, the catalyst is self-supported, eliminating the overpotential associated with the catalyst/support interface. PMID:25910892

  2. International Conference on Rapidly Quenched Metals, 2nd, Massachusetts Institute of Technology, Cambridge, Mass., November 17-19, 1975, Proceedings

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The range of topics covered by the papers includes: rapid quenching (and specifically splat quenching) of metals, spin quenching, levitation melting, rapid quenching from liquid state; amorphous metal phases and metastable phases, metallic glasses, ribbons, splats, films, metal ribbon reinforced resins; crystallization of metallic glasses, and ferromagnetic amorphous alloys. Structural models for amorphous metals, splat-quenching equipment, and measurements of the properties of amorphous and noncrystalline metals and metallic glasses are also discussed, in addition to: fatigue events (crack propagation) in amorphous metals, fracture behavior in rapidly quenched metals, ductile superconducting Cu-Nb-Sn alloys, and semiconducting amorphous V205 alloy. Individual items are announced in this issue.

  3. Process for making a noble metal on tin oxide catalyst

    NASA Technical Reports Server (NTRS)

    Upchurch, Billy T. (Inventor); Davis, Patricia (Inventor); Miller, Irvin M. (Inventor)

    1989-01-01

    A quantity of reagent grade tin metal or compound, chloride-free, and high-surface-area silica spheres are placed in deionized water, followed by deaerating the mixture by boiling and adding an oxidizing agent, such as nitric acid. The nitric acid oxidizes the tin to metastannic acid which coats the spheres because the acid is absorbed on the substrate. The metastannic acid becomes tin oxide upon drying and calcining. The tin-oxide coated silica spheres are then placed in water and boiled. A chloride-free precious metal compound in aqueous solution is then added to the mixture containing the spheres, and the precious metal compound is reduced to a precious metal by use of a suitable reducing agent such as formic acid. Very beneficial results were obtained using the precious metal compound tetraammine platinum(II) hydroxide.

  4. First analytical evidences of precious colourants on Mediterranean illuminated manuscripts

    NASA Astrophysics Data System (ADS)

    Aceto, M.; Agostino, A.; Fenoglio, G.; Baraldi, P.; Zannini, P.; Hofmann, C.; Gamillscheg, E.

    2012-09-01

    Two Byzantine VI century manuscripts known as Vienna Dioskurides and Vienna Genesis, held in the Austrian National Library at Vienna, were analysed with in situ non-invasive techniques. Raman spectroscopy, UV-Vis diffuse reflectance spectrophotometry with optic fibres and X-ray fluorescence spectrometry were used to characterise the palette of these early Middle Ages manuscripts. The analytical study was performed to have a better knowledge on the colourants used by ancient miniature painters, a subject known more on the basis of traditional sources (i.e. medieval treatises) than of analytical evidences. Indeed these illuminated manuscripts are, to the authors' knowledge, among the oldest ever being analysed, so that the colourants found in them can be considered among the oldest evidences of their use. The main feature of Vienna Dioskurides and Vienna Genesis palettes is their richness, exemplified by the simultaneous presence of gold and ultramarine blue; in Vienna Dioskurides cinnabar is also present. Information regarding ultramarine blue is surprising, being the analytical evidence of the use of this precious pigment at least three centuries before its use in Western manuscripts, a feature justified by the fact that the Byzantine Empire was the dominant culture in early Middle Ages in the Mediterranean World. Other colourants include azurite and indigo, red lead, orpiment, red and yellow ochres, while a mixture of blue and yellow colourants, known as vergaut, was used to render green hues. Organic colourants were also used, such as madder and Tyrian purple, the latter employed to dye the parchment of Vienna Genesis.

  5. Highly Dispersed Metal Catalyst for Fuel Cell Electrodes

    SciTech Connect

    2009-03-01

    This factsheet describes a study that will bring industrial catalyst experience to fuel cell research. Specifically, industrial catalysts, such as those used in platforming, utilize precious metal platinum as an active component in a finely dispersed form.

  6. Ni-BaTiO3-Based Base-Metal Electrode (BME) Ceramic Capacitors for Space Applications

    NASA Technical Reports Server (NTRS)

    Liu, Donhang; Fetter, Lula; Meinhold, Bruce

    2015-01-01

    A multi-layer ceramic capacitor (MLCC) is a high-temperature (1350C typical) co-fired ceramic monolithic that is composed of many layers of alternately stacked oxide-based dielectric and internal metal electrodes. To make the dielectric layers insulating and the metal electrode layers conducting, only highly oxidation-resistant precious metals, such as platinum, palladium, and silver, can be used for the co-firing of insulating MLCCs in a regular air atmosphere. MLCCs made with precious metals as internal electrodes and terminations are called precious-metal electrode (PME) capacitors. Currently, all military and space-level applications only address the use of PME capacitors.

  7. Leadership and Strategic Management: Keys to Institutional Priorities and Planning

    ERIC Educational Resources Information Center

    Taylor, James S.; de Lourdes Machado, Maria; Peterson, Marvin W.

    2008-01-01

    Allocating and managing resources have always been important cornerstones of institutional leadership. Institutional resources include financial, physical and human components. Even in the best of times, it is a challenge to do this effectively. In times of diminished and shrinking resources, distributing these precious commodities across the…

  8. Pressure pyrolysed non-precious oxygen reduction catalysts for proton exchange membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Nallathambi, Vijayadurga

    2011-12-01

    Worldwide energy demand has driven long-term efforts towards developing a clean, hydrogen-based energy economy. Polymer electrolyte membrane fuel cells (PEMFC) are low emissions and high efficiency devices that utilize the power of hydrogen and are a key enabling technology for the hydrogen economy. Carbon supported platinum-black is the state-of the art catalyst for oxygen reduction in a PEMFC because it can withstand the acidic environment. However, the high cost and low abundance of this precious metal has limited large-scale commercialization of PEMFCs. Current efforts focus on developing alternative inexpensive, non-noble metal-based catalysts for oxygen reduction with performance comparable to conventional platinum based electrocatalysts. In this work, inexpensive metal-nitrogen-carbon (MNC) catalysts have been synthesized by pyrolyzing transition metal and nitrogen precursors together with high surface area carbon materials in a closed, constant-volume quartz tube. High pressure generated due to nitrogen precursor evaporation lead to increased surface nitrogen content in the catalysts post-pyrolysis. Electrochemical oxygen reduction activity of MNC catalysts was analyzed using half-cell Rotating Ring Disc Electrode (RRDE) studies. The effect of nitrogen precursor morphology on the generation of active sites has been explored in detail. By increasing the Nitrogen/Carbon ratio of the nitrogen precursor, the accessible active site density increased by reducing carbon deposition in the pores of the carbon support during pyrolysis. The most active catalysts were obtained using melamine, having a N/C ratio of 2. Single PEMFC measurements employing MNC catalysts as cathodes indicated kinetic current density as high as 15 A cm-3 at 0.8 ViR-free and over 100 h of stable current at 0.5 V were observed. Effects of carbon free ammonia generating solid nitrogen precursors such as urea and ammonium carbamate were also studied. These precursors etched the carbon support

  9. High temperature, oxidation resistant noble metal-Al alloy thermocouple

    NASA Technical Reports Server (NTRS)

    Smialek, James L. (Inventor); Gedwill, Michael G. (Inventor)

    1994-01-01

    A thermocouple is disclosed. The thermocouple is comprised of an electropositive leg formed of a noble metal-Al alloy and an electronegative leg electrically joined to form a thermocouple junction. The thermocouple provides for accurate and reproducible measurement of high temperatures (600 - 1300 C) in inert, oxidizing or reducing environments, gases, or vacuum. Furthermore, the thermocouple circumvents the need for expensive, strategic precious metals such as rhodium as a constituent component. Selective oxidation of rhodium is also thereby precluded.

  10. Precious bits: frame synchronization in Jet Propulsion Laboratory's Advanced Multi-Mission Operations System (AMMOS)

    NASA Technical Reports Server (NTRS)

    Wilson, E.

    2001-01-01

    The Jet Propulsion Laboratory's (JPL) Advanced Multi-Mission Operations System (AMMOS) system processes data received from deep-space spacecraft, where error rates are high, bit rates are low, and every bit is precious. Frame synchronization and data extraction as performed by AMMOS enhanced data acquisition and reliability for maximum data return and validity.

  11. 50 CFR 665.160 - American Samoa precious coral fisheries. [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false American Samoa precious coral fisheries. 665.160 Section 665.160 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE (CONTINUED) FISHERIES IN THE WESTERN...

  12. 50 CFR 665.160 - American Samoa precious coral fisheries. [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false American Samoa precious coral fisheries. 665.160 Section 665.160 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE (CONTINUED) FISHERIES IN THE WESTERN...

  13. 50 CFR 665.160 - American Samoa precious coral fisheries. [Reserved

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false American Samoa precious coral fisheries. 665.160 Section 665.160 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE (CONTINUED) FISHERIES IN THE WESTERN...

  14. 76 FR 67476 - Silicon Metal From China; Institution of a Five-Year Review Concerning the Antidumping Duty Order...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-01

    ...), as most recently amended at 74 FR 2847 (January 16, 2009). \\1\\ No response to this request for... silicon metal from China (56 FR 26649). Following first five-year reviews by Commerce and the Commission... silicon metal from China (66 FR 10669). Following second five-year reviews by Commerce and the...

  15. 75 FR 81443 - Guides for the Jewelry, Precious Metals, and Pewter Industries

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-28

    ... the term ``platinum.'' \\3\\ Specifically, Section 7(a) states: \\3\\ On April 8, 1997 (62 FR 16669), the...-deceptively platinum-clad, filled, coated, or overlay jewelry products. \\7\\ 70 FR 38834 (July 6, 2005). Based... Commission extended the comment period until August 25, 2008.\\8\\ \\8\\ 73 FR 22848 (Apr. 28, 2008). C. The...

  16. Precious metal-free catalyst for purification of automotive exhausts: NO dissociation on Cu oxide surfaces

    NASA Astrophysics Data System (ADS)

    Kasai, Hideaki; Padama, Allan Abraham; Moreno, Joaquin Lorenzo

    2014-03-01

    The dissociation of NOx molecule on catalysts is the rate-limiting step for its reduction process and is the subject of recent investigations related to exhaust gas purification. Three-way catalysts which are composed of Rh, Pd and Pt, are known to work well for such purpose; however, their expensive cost hinders their applicability. In this work, Computational Materials Design based on density functional theory was employed to test the efficiency of Cu-based catalysts for NO dissociation. It was found that the dissociation path of NO on Cu-terminated Cu2O(111) and CuO(110) surfaces is comparable with Rh(111). This is attributed to the modified electronic structure of the surface Cu atoms of Cu oxides in comparison with Cu(111). The calculated NO dissociation barriers are lower and the binding energies of co-adsorbed N and O atoms are weaker on Cu oxides than on Rh(111), which is favorable for subsequent reactions. Our experimental collaborator had also verified that Cu oxides can be better catalysts than Rh, Pd and Pt for the purification of exhaust gases. The details of this work and the oxidation of CO in the presence of dissociated NO will be discussed in the meeting.

  17. Base and precious metal occurrences along the San Andreas Fault, Point Delgada, California

    USGS Publications Warehouse

    McLaughlin, Robert J.; Sorg, D.H.; Ohlin, H.N.; Heropoulos, Chris

    1979-01-01

    Previously unrecognized veins containing lead, zinc, and copper sulfide minerals at Point Delgada, Calif., are associated with late Mesozoic(?) and Tertiary volcanic and sedimentary rocks of the Franciscan assemblage. Sulfide minerals include pyrite, sphalerite, galena, and minor chalcopyrite, and galena-rich samples contain substantial amounts of silver. These minerals occur in a quartz-carbonate gangue along northeast-trending faults and fractures that exhibit (left?) lateral and vertical slip. The sense of fault movement and the northeasterly strike are consistent with predicted conjugate fault sets of the present San Andreas fault system. The sulfide mineralization is younger than the Franciscan rocks of Point Delgada and King Range, and it may have accompanied or postdated the inception of San Andreas faulting. Mineralization largely preceded uplift, the formation of a marine terrace, and the emplacement of landslide-related debris-flow breccias that overlie the mineralized rocks and truncate the sulfide veins. These field relations indicate that the sulfide mineralization and inception of San Andreas faulting were clearly more recent than the early Miocene and that the mineralization could be younger than about 1.2 m.y. The sulfide veins at Point Delgada may be of economic significance. However, prior to any exploitation of the occurrence, economic and environmental conflicts of interest involving private land ownership, the Shelter Cove home development, and proximity of the coast must be resolved.

  18. Late paleozoic base and precious metal deposits, East Tianshan, Xinjiang, China: Characteristics and geodynamic setting

    USGS Publications Warehouse

    Mao, J.; Goldfarb, R.J.; Wang, Y.; Hart, C.J.; Wang, Z.; Yang, J.

    2005-01-01

    The East Tianshan is a remote Gobi area located in eastern Xinjiang, northwestern China. In the past several years, a number of gold, porphyry copper, and Fe(-Cu) and Cu-Ag-Pb-Zn skarn deposits have been discovered there and are attracting exploration interest. The East Tianshan is located between the Junggar block to the north and early Paleozoic terranes of the Middle Tianshan to the south. It is part of a Hercynian orogen with three distinct E-W-trending tectonic belts: the Devonian-Early Carboniferous Tousuquan-Dananhu island arc on the north and the Carboniferous Aqishan - Yamansu rift basin to the south, which are separated by rocks of the Kanggurtag shear zone. The porphyry deposits, dated at 322 Ma, are related to the late evolutionary stages of a subduction-related oceanic or continental margin arc. In contrast, the skarn, gold, and magmatic Ni-Cu deposits are associated with post-collisional tectonics at ca. 290-270 Ma. These Late Carboniferous - Early Permian deposits are associated with large-scale emplacement and eruption of magmas possibly caused by lithosphere delamination and rifting within the East Tianshan.

  19. 76 FR 67793 - Notification of Expanded Pricing Grid for Precious Metals Products Containing Platinum and Gold...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-02

    ... and Gold--Excluding Commemorative Gold Coins AGENCY: United States Mint, Department of the Treasury..., 2009, outlining the new pricing methodology for numismatic products containing platinum and gold. Since that time, the price of platinum and gold has increased considerably, and is approaching the...

  20. Integrated Water Gas Shift Membrane Reactors Utilizing Novel, Non Precious Metal Mixed Matrix Membrane

    SciTech Connect

    Ferraris, John

    2013-09-30

    Nanoparticles of zeolitic imidazolate frameworks and other related hybrid materials were prepared by modifying published synthesis procedures by introducing bases, changing stoichiometric ratios, or adjusting reaction conditions. These materials were stable at temperatures >300 °C and were compatible with the polymer matrices used to prepare mixed- matrix membranes (MMMs). MMMs tested at 300 °C exhibited a >30 fold increase in permeability, compared to those measured at 35 °C, while maintaining H{sub 2}/CO{sub 2} selectivity. Measurements at high pressure (up to 30 atm) and high temperature (up to 300 °C) resulted in an increase in gas flux across the membrane with retention of selectivity. No variations in permeability were observed at high pressures at either 35 or 300 °C. CO{sub 2}-induced plasticization was not observed for Matrimid®, VTEC, and PBI polymers or their MMMs at 30 atm and 300 °C. Membrane surface modification by cross-linking with ethanol diamine resulted in an increase in H{sub 2}/CO{sub 2} selectivity at 35 °C. Spectrometric analysis showed that the cross-linking was effective to temperatures <150 °C. At higher temperatures, the cross-linked membranes exhibit a H{sub 2}/CO{sub 2} selectivity similar to the uncross-linked polymer. Performance of the polybenzimidazole (PBI) hollow fibers prepared at Santa Fe Science and Technology (SFST, Inc.) showed increased flux o to a flat PBI membrane. A water-gas shift reactor has been built and currently being optimized for testing under DOE conditions.

  1. 78 FR 26289 - Guides for the Jewelry, Precious Metals, and Pewter Industries: Public Roundtable

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-06

    ... a roundtable on June 19, 2013. \\1\\ 77 FR 39201 (July 2, 2012). To facilitate a productive roundtable... 2, 2012 with the publication of a Federal Register Notice (``2012 Notice'') seeking public comments... avoid unfair or deceptive trade practices.\\2\\ \\2\\ The Commission issues industry guides to help...

  2. Enterprise systems in financial sector - an application in precious metal trading forecasting

    NASA Astrophysics Data System (ADS)

    Chen, Xiaozhu; Fang, Yiwei

    2013-11-01

    The use of enterprise systems has become increasingly popular in the financial service industry. This paper discusses the applications of enterprise systems in the financial sectors and presents an application in gold price forecasting. We carefully examine the impacts of a few most widely assumed factors that have significant impact on the long-term gold price using statistical regression techniques. The analysis on our proposed linear regression mode indicates that the United States ultra scale of M2 money supply has been the most important catalyst for the rising price of gold, and the CRB index upward trend has also been the weighty factor for pushing up the gold price. In addition, the gold price has a low negative correlation with the Dow Jones Industrial Average, and low positive correlations with the US dollar index and the gold ETFs holdings.

  3. The development of dental alloys conserving precious metals: improving corrosion resistance by controlled ageing.

    PubMed

    Yasuda, K; Hisatsune, K; Ohta, M

    1983-03-01

    To determine the conditions which confer desirable mechanical properties and corrosion resistance upon dental alloys, age-hardening mechanism and the associated structural changes were studied by means of resistometric measurements, hardness tests, electron microscope observations and electron diffraction studies. Five commercial dental alloys, a high-gold content alloy, a low-gold alloy and three Au-Ag-Pd silver-based alloys and two experimental gold alloys, were examined. The structural and morphological changes which gave rise to age-hardening were classified into five types of phase transformation, i.e., (1) the formation of the AuCu I type superlattice and its twinning characterized by a stair-step mode, (2) the formation of the AuCu II type super-lattice with periodic antiphase domain structure, (3) the precipitation of the CuPd superlattice with fct structure analogous to the AuCu I type, (4) spinodal decomposition giving rise to a modulated structure and (5) the formation of the lamellar structure developed from grain boundaries by discontinuous precipitations. (1), (2) and (3) made a contribution to corrosion resistance superior to (4) and (5). A lamellar structure was prone to a high corrosion rate. The results obtained in this study are useful in predicting age-hardening characteristics and structural changes associated with corrosion, because the microstructural variation induced by ageing as well as nobility of alloys affects greatly their corrosion resistance. PMID:6574108

  4. Surface treatment agent for dental metals using a thiirane monomer and a phosphoric acid monomer.

    PubMed

    Kadoma, Yoshinori

    2002-06-01

    To develop a new surface treatment agent which improves the bond strength of adhesive resin to both non-precious and precious metals, experimental treatment agents containing both an adhesive bonding promoter for precious metals and one for non-precious metals were prepared by dissolving epithioalkyl methacrylate (EP3MA or EP8MA) and 10-methacryloyloxydecyl dihydrogen phosphate (MDP) in acetone. The surfaces of dental metals were treated by the treatment agents and metal specimens were butt-jointed together with MMA-PMMA resins. After 2,000 thermal cyclings in water at temperatures of 4 and 60 degrees C, tensile bond strengths were measured. The effectiveness of surface treatments was evaluated by tensile bond strengths and microscopic failure mode analysis after the tensile test. The combined treatment of EP3MA-MDP or EP8MA-MDP was used effectively for non-precious metals as well as precious metals, and was shown to be extremely effective compared with the single treatment of EP3MA, EP8MA, or MDP. PMID:12238784

  5. 77 FR 59975 - Certain Folding Metal Tables and Chairs From China; Institution of a Five-Year Review Concerning...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-01

    ... an antidumping duty order on imports of certain folding metal tables and chairs from China (67 FR... part 201), and part 207, subparts A, D, E, and F (19 CFR part 207), as most recently amended at 74 FR... chairs from China (72 FR 62626). The Commission is now conducting a second review to determine...

  6. A non-precious electrocatalyst for oxygen reduction based on simple heat-treated precursors

    SciTech Connect

    Chung, Hoon T; Zelenay, Piotr; Johnston, Christina; Garzon, Fernando

    2008-07-18

    Some active non-precious catalyst was made by simple heat treated novel precursors. The power density obtained in the H{sub 2}/O{sub 2} fed PEM fuel cells is as high as 0.22 W/cm{sup 2}{sub MEA} at 0.65 V. The active site seems to have little relevance with the nitrogen. We are now working on to figure out the active site(s) in this catalyst.

  7. Virtual Institute of Microbial Stress and Survival: Deduction of Stress Response Pathways in Metal and Radionuclide Reducing Microorganisms

    SciTech Connect

    2004-04-17

    The projects application goals are to: (1) To understand bacterial stress-response to the unique stressors in metal/radionuclide contamination sites; (2) To turn this understanding into a quantitative, data-driven model for exploring policies for natural and biostimulatory bioremediation; (3) To implement proposed policies in the field and compare results to model predictions; and (4) Close the experimental/computation cycle by using discrepancies between models and predictions to drive new measurements and construction of new models. The projects science goals are to: (1) Compare physiological and molecular response of three target microorganisms to environmental perturbation; (2) Deduce the underlying regulatory pathways that control these responses through analysis of phenotype, functional genomic, and molecular interaction data; (3) Use differences in the cellular responses among the target organisms to understand niche specific adaptations of the stress and metal reduction pathways; (4) From this analysis derive an understanding of the mechanisms of pathway evolution in the environment; and (5) Ultimately, derive dynamical models for the control of these pathways to predict how natural stimulation can optimize growth and metal reduction efficiency at field sites.

  8. Iron phthalocyanine and nitrogen-doped graphene composite as a novel non-precious catalyst for the oxygen reduction reaction.

    PubMed

    Zhang, Chenzhen; Hao, Rui; Yin, Han; Liu, Fei; Hou, Yanglong

    2012-12-01

    We develop a facile method for the synthesis of an iron phthalocyanine (FePc) and nitrogen-doped graphene (NG) composite as a novel and efficient non-precious catalyst in the oxygen reduction reaction (ORR). The resulting product exhibits superior ORR catalytic activity, excellent tolerance to methanol crossover, and comparable stability to commercial Pt/C, which leads to the invention of a new non-precious catalyst for ORR in fuel cells. PMID:23086132

  9. Results of studying creep and long-term strength of metals at the Institute of Mechanics at the Lomonosov Moscow State University (To Yu. N. Rabotnov's Anniversary)

    NASA Astrophysics Data System (ADS)

    Lokoshchenko, A. M.

    2014-01-01

    Basic results of experimental and theoretical research of creep processes and long-term strength of metals obtained by researchers of the Institute of Mechanics at the Lomonosov Moscow State University are presented. These results further develop and refine the kinetic theory of creep and long-duration strength proposed by Yu. N. Rabotnov. Some problems arising in formulating various types of kinetic equations and describing experimental data for materials that can be considered as statically homogeneous materials (in studying the process of deformation and rupture of such materials, there is no need to study the evolution of individual cracks) are considered. The main specific features of metal creep models at constant and variable stresses, in uniaxial and complex stress states, and with allowance for one or two damage parameters are described. Criterial and kinetic approaches used to determine long-term strength under conditions of a complex stress state are considered. Methods of modeling the metal behavior in an aggressive medium are described. A possibility of using these models for solving engineering problems is demonstrated.

  10. Method for extracting copper, silver and related metals

    DOEpatents

    Moyer, Bruce A.; McDowell, W. J.

    1990-01-01

    A process for selectively extracting precious metals such as silver and gold concurrent with copper extraction from aqueous solutions containing the same. The process utilizes tetrathiamacrocycles and high molecular weight organic acids that exhibit a synergistic relationship when complexing with certain metal ions thereby removing them from ore leach solutions.

  11. Method for extracting copper, silver and related metals

    DOEpatents

    Moyer, B.A.; McDowell, W.J.

    1987-10-23

    A process for selectively extracting precious metals such as silver and gold concurrent with copper extraction from aqueous solutions containing the same. The process utilizes tetrathiamacrocycles and high molecular weight organic acids that exhibit a synergistic relationship when complexing with certain metal ions thereby removing them from ore leach solutions.

  12. Method for extracting copper, silver and related metals

    SciTech Connect

    Moyer, B.A.; McDowell, W.J.

    1990-05-22

    This patent describes a process for selectively extracting precious metal such as silver and gold concurrent with copper extraction from aqueous solutions containing the same. The process utilizes tetrathiamacrocycles and high molecular weight organic acids that exhibit a synergistic relationship when complexing with certain metal ions thereby removing them from ore leach solutions.

  13. Effective and selective recovery of gold and palladium ions from metal wastewater using a sulfothermophilic red alga, Galdieria sulphuraria.

    PubMed

    Ju, Xiaohui; Igarashi, Kensuke; Miyashita, Shin-Ichi; Mitsuhashi, Hiroaki; Inagaki, Kazumi; Fujii, Shin-Ichiro; Sawada, Hitomi; Kuwabara, Tomohiko; Minoda, Ayumi

    2016-07-01

    The demand for precious metals has increased in recent years. However, low concentrations of precious metals dissolved in wastewater are yet to be recovered because of high operation costs and technical problems. The unicellular red alga, Galdieria sulphuraria, efficiently absorbs precious metals through biosorption. In this study, over 90% of gold and palladium could be selectively recovered from aqua regia-based metal wastewater by using G. sulphuraria. These metals were eluted from the cells into ammonium solutions containing 0.2M ammonium salts without other contaminating metals. The use of G. sulphuraria is an eco-friendly and cost-effective way of recovering low concentrations of gold and palladium discarded in metal wastewater. PMID:27118429

  14. Hydrothermal fluids responsible for the formation of precious minerals in the Nigerian Younger Granite Province

    NASA Astrophysics Data System (ADS)

    Abaa, S. I.

    1991-04-01

    Preliminary investigations in the Younger Granite Province of Nigeria have revealed that precious and semi-precious minerals like rubies, sapphires, emeralds, aquamarine, zircon and fluorite can be found in the region. The gem minerals are shown to have been produced either by direct deposition along fissures, veins and greisens by hydrothermal fluids or as a result of hydrothermal fluids reacting with wall-rocks. These wall rocks are either biotite granites from which the hydrothermal fluids originated or basement rocks or any other rocks which the biotite granites intrude and their residual hydrothermal fluids have invaded. The hydrothermal fluids appear to have been rich in alkalis (Na+, K+, etc.), rare elements (Be, Zr, F, REE, etc.) and siliceous. As these fluids rose through fractures and channel ways through the rocks, they either deposited the gem minerals in the fractures at the appropriate stability conditions or reacted with the wall-rocks producing the gem minerals at the expense of elements like Ca and A1 in the minerals of these rocks.

  15. The Radial Growth Rate of Japanese Precious Corals Using Pb-210 Dating Method

    NASA Astrophysics Data System (ADS)

    Yamada, M.; Iwasaki, N.; Suzuki, A.; Aono, T.

    2014-12-01

    Precious corals belong to the subclass Octocorallia of the class Anthozoa. Its major component is calcium carbonate and the crystal structure is high-Mg calcite. Their skeletal axes are used for jewellery, rosary, amulet, etc. They are found mainly in the Japanese coast, the Mediterranean and off the Midway Islands and they are distributed at a depth of 100 m to 1500m. The growing skeletons of precious corals have potential for recording environmental change. Pb-210 is a naturally occurring radionuclide with a half-life of 22.3 years. Pb-210 is a natural sediment marker suitable for dating events that have occurred over the past 100 years and has been used to measure the sedimentation rates of lake and coastal marine sediments. The objectives of this study were to measure the Pb-210 concentration in the skeletons of Japanese red coral, pink coral and white coral and to estimate the radial growth rate using Pb-210 dating method. The radial growth rate of the skeleton can be estimated by the gradual decrease in Pb-210 concentrations measured from the surface inwards. The radial growth rate of the pink coral skeleton (Corallium elatius), collected at depths of 200 to 300 m off the coast of the Ryukyu Islands, Japan, was 0.15 mm/year, so slow that it would take as long as 50 years for a colony to grow to 15 mm in diameter.

  16. Highly durable and active non-precious air cathode catalyst for zinc air battery

    NASA Astrophysics Data System (ADS)

    Chen, Zhu; Choi, Ja-Yeon; Wang, Haijiang; Li, Hui; Chen, Zhongwei

    The electrochemical stability of non-precious FeCo-EDA and commercial Pt/C cathode catalysts for zinc air battery have been compared using accelerated degradation test (ADT) in alkaline condition. Outstanding oxygen reduction reaction (ORR) stability of the FeCo-EDA catalyst was observed compared with the commercial Pt/C catalyst. The FeCo-EDA catalyst retained 80% of the initial mass activity for ORR whereas the commercial Pt/C catalyst retained only 32% of the initial mass activity after ADT. Additionally, the FeCo-EDA catalyst exhibited a nearly three times higher mass activity compared to that of the commercial Pt/C catalyst after ADT. Furthermore, single cell test of the FeCo-EDA and Pt/C catalysts was performed where both catalysts exhibited pseudolinear behaviour in the 12-500 mA cm -2 range. In addition, 67% higher peak power density was observed from the FeCo-EDA catalyst compared with commercial Pt/C. Based on the half cell and single cell tests the non-precious FeCo-EDA catalyst is a very promising ORR electrocatalyst for zinc air battery.

  17. Habitat Evaluation Procedures (HEP) Report; Precious Lands Wildlife Management Area, Technical Report 2000-2003.

    SciTech Connect

    Kozusko, Shana

    2003-12-01

    The Nez Perce Tribe (NPT) currently manages a 15,325 acre parcel of land known as the Precious Lands Wildlife Management Area that was purchased as mitigation for losses incurred by construction of the four lower Snake River dams. The Management Area is located in northern Wallowa County, Oregon and southern Asotin County, Washington (Figure 1). It is divided into three management parcels--the Buford parcel is located on Buford Creek and straddles the WA-OR state line, and the Tamarack and Basin parcels are contiguous to each other and located between the Joseph Creek and Cottonwood Creek drainages in Wallowa County, OR. The project was developed under the Pacific Northwest Electric Power Planning and Conservation Act of 1980 (P.L. 96-501), with funding from the Bonneville Power Administration (BPA). The acreage protected under this contract will be credited to BPA as habitat permanently dedicated to wildlife and wildlife mitigation. A modeling strategy known as Habitat Evaluation Procedure (HEP) was developed by the U.S. Fish and Wildlife Service and adopted by BPA as a habitat equivalency accounting system. Nine wildlife species models were used to evaluate distinct cover type features and provide a measure of habitat quality. Models measure a wide range of life requisite variables for each species and monitor overall trends in vegetation community health and diversity. One product of HEP is an evaluation of habitat quality expressed in Habitat Units (HUs). This HU accounting system is used to determine the amount of credit BPA receives for mitigation lands. After construction of the four lower Snake River dams, a HEP loss assessment was conducted to determine how many Habitat Units were inundated behind the dams. Twelve target species were used in that evaluation: Canada goose, mallard, river otter, downy woodpecker, song sparrow, yellow warbler, marsh wren, western meadowlark, chukar, ring-necked pheasant, California quail, and mule deer. The U.S. Army Corp of

  18. IFLA General Conference, 1985. Division on Collections and Services. Section on Rare and Precious Books and Documents. Papers.

    ERIC Educational Resources Information Center

    International Federation of Library Associations, The Hague (Netherlands).

    Papers on rare books and precious documents which were presented at the 1985 International Federation of Library Associations (IFLA) conference include: (1) "The Planned Census of Incunabula in Libraries in the FRG (Federal Republic of Germany): A Contribution to Retrospective Bibliographic Control" (Franz Georg Kaltwasser, West Germany); (2) "The…

  19. Peculiarities of the irisation in precious opals in view of their mosaic-cluster (frustumation) inner fabric

    NASA Astrophysics Data System (ADS)

    Povarennykh, M. Yu.; Knot'ko, A. V.; Matvienko, E. N.; Plechov, P. Yu.; Burmistrov, A. A.; Luksha, V. L.

    2016-04-01

    A direct correlation was shown for the first time between mosaic irisation patterns in synthetic and natural precious opals (from Australia, Ethiopia, Honduras, Slovakia, and Russia) and their frustumational (lump or mosaic-cluster) inner structure by means of photoluminescence, X-ray phase analysis, IR and Raman spectroscopy, and scanning electron microscopy.

  20. Supported molten-metal catalysts

    DOEpatents

    Datta, Ravindra; Singh, Ajeet; Halasz, Istvan; Serban, Manuela

    2001-01-01

    An entirely new class of catalysts called supported molten-metal catalysts, SMMC, which can replace some of the existing precious metal catalysts used in the production of fuels, commodity chemicals, and fine chemicals, as well as in combating pollution. SMMC are based on supporting ultra-thin films or micro-droplets of the relatively low-melting (<600.degree. C.), inexpensive, and abundant metals and semimetals from groups 1, 12, 13, 14, 15 and 16, of the periodic table, or their alloys and intermetallic compounds, on porous refractory supports, much like supported microcrystallites of the traditional solid metal catalysts. It thus provides orders of magnitude higher surface area than is obtainable in conventional reactors containing molten metals in pool form and also avoids corrosion. These have so far been the chief stumbling blocks in the application of molten metal catalysts.

  1. Dynamics of formation of Ru, Os, Ir and Au metal nanocrystals on doped graphitic surfaces.

    PubMed

    Pitto-Barry, Anaïs; Sadler, Peter J; Barry, Nicolas P E

    2016-03-11

    The fabrication of precious metal (ruthenium, osmium, gold, and iridium) nanocrystals from single atoms has been studied in real-time. The dynamics of the first stage of the metal nanocrystallisation on a doped (B,S)-graphitic surface are identified, captured, and reported. PMID:26698913

  2. Cyanobacteria: A Precious Bio-resource in Agriculture, Ecosystem, and Environmental Sustainability

    PubMed Central

    Singh, Jay Shankar; Kumar, Arun; Rai, Amar N.; Singh, Devendra P.

    2016-01-01

    Keeping in view, the challenges concerning agro-ecosystem and environment, the recent developments in biotechnology offers a more reliable approach to address the food security for future generations and also resolve the complex environmental problems. Several unique features of cyanobacteria such as oxygenic photosynthesis, high biomass yield, growth on non-arable lands and a wide variety of water sources (contaminated and polluted waters), generation of useful by-products and bio-fuels, enhancing the soil fertility and reducing green house gas emissions, have collectively offered these bio-agents as the precious bio-resource for sustainable development. Cyanobacterial biomass is the effective bio-fertilizer source to improve soil physico-chemical characteristics such as water-holding capacity and mineral nutrient status of the degraded lands. The unique characteristics of cyanobacteria include their ubiquity presence, short generation time and capability to fix the atmospheric N2. Similar to other prokaryotic bacteria, the cyanobacteria are increasingly applied as bio-inoculants for improving soil fertility and environmental quality. Genetically engineered cyanobacteria have been devised with the novel genes for the production of a number of bio-fuels such as bio-diesel, bio-hydrogen, bio-methane, synga, and therefore, open new avenues for the generation of bio-fuels in the economically sustainable manner. This review is an effort to enlist the valuable information about the qualities of cyanobacteria and their potential role in solving the agricultural and environmental problems for the future welfare of the planet. PMID:27148218

  3. Cyanobacteria: A Precious Bio-resource in Agriculture, Ecosystem, and Environmental Sustainability.

    PubMed

    Singh, Jay Shankar; Kumar, Arun; Rai, Amar N; Singh, Devendra P

    2016-01-01

    Keeping in view, the challenges concerning agro-ecosystem and environment, the recent developments in biotechnology offers a more reliable approach to address the food security for future generations and also resolve the complex environmental problems. Several unique features of cyanobacteria such as oxygenic photosynthesis, high biomass yield, growth on non-arable lands and a wide variety of water sources (contaminated and polluted waters), generation of useful by-products and bio-fuels, enhancing the soil fertility and reducing green house gas emissions, have collectively offered these bio-agents as the precious bio-resource for sustainable development. Cyanobacterial biomass is the effective bio-fertilizer source to improve soil physico-chemical characteristics such as water-holding capacity and mineral nutrient status of the degraded lands. The unique characteristics of cyanobacteria include their ubiquity presence, short generation time and capability to fix the atmospheric N2. Similar to other prokaryotic bacteria, the cyanobacteria are increasingly applied as bio-inoculants for improving soil fertility and environmental quality. Genetically engineered cyanobacteria have been devised with the novel genes for the production of a number of bio-fuels such as bio-diesel, bio-hydrogen, bio-methane, synga, and therefore, open new avenues for the generation of bio-fuels in the economically sustainable manner. This review is an effort to enlist the valuable information about the qualities of cyanobacteria and their potential role in solving the agricultural and environmental problems for the future welfare of the planet. PMID:27148218

  4. Ornamental Stones and Gemstones: The limits of heritage stone designation: The case for and against Australian Precious Opal

    NASA Astrophysics Data System (ADS)

    Cooper, Barry

    2015-04-01

    When the international designation of natural stone types was first mooted in 2007, stones that were utilised in building and construction were the primary focus of attention. However following public discussion it soon became apparent that sculptural stones, stone used for utilitarian purposes such as millstones, as well as archaeological materials including stones used by early man could all be positively assessed as a potential Global Heritage Stone Resource (GHSR). Over the past 2 years it has been realised there is also a range of ornamental and semi-precious stones that may also be considered in the same international context. Examples in this respect include Imperial Porphyry sourced from Egypt that was much prized in the ancient world and "Derbyshire Blue John" a variety of fluorspar from central England that was used for vases, chalices, urns, candle sticks, jars, bowls door, jewellery and fire-place surrounds, especially in the 18th and 19th centuries. It is at this point that rock materials, sometimes used as gemstones, impinge on the domain of typical heritage stones. In Australia, the gemstone most identifiable with the country is precious opal formed by sedimentary processes in the Great Artesian Basin. In this paper the question is asked whether "Australian Precious Opal" could be or should be considered as a heritage stone of international significance. Immediately Australian Precious Opal satisfies several GHSR criteria including historic use for more than 50 years and wide-ranging utilisation for prestige jewellery around the world. It is also recognised as a cultural icon including association with national identity in Australia as it is legally defined as Australia's "National Gemstone" as well as being the "Gemstone Emblem" for the State of South Australia. Opal continues to be mined. Designation of Australian Precious Opal as a Global Heritage Stone Resource would likely involve formal international recognition of Australian opal in the

  5. Harvesting effects, recovery mechanisms, and management strategies for a long-lived and structural precious coral.

    PubMed

    Montero-Serra, Ignasi; Linares, Cristina; García, Marina; Pancaldi, Francesca; Frleta-Valić, Maša; Ledoux, Jean-Baptiste; Zuberer, Frederic; Merad, Djamel; Drap, Pierre; Garrabou, Joaquim

    2015-01-01

    Overexploitation is a major threat for the integrity of marine ecosystems. Understanding the ecological consequences of different extractive practices and the mechanisms underlying the recovery of populations is essential to ensure sustainable management plans. Precious corals are long-lived structural invertebrates, historically overfished, and their conservation is currently a worldwide concern. However, the processes underlying their recovery are poorly known. Here, we examined harvesting effects and recovery mechanisms of red coral Corallium rubrum by analyzing long-term photographic series taken on two populations that were harvested. We compared the relative importance of reproduction and re-growth as drivers of resilience. Harvesting heavily impacted coral populations causing large decreases in biomass and strong size-class distribution shifts towards populations dominated by small colonies. At the end of the study (after 4 and 7 years) only partial recovery was observed. The observed general pattern of low recruitment and high mortality of new recruits demonstrated limited effects of reproduction on population recovery. Adversely, low mortality of partially harvested adults and a large proportion of colonies showing new branches highlighted the importance of re-growth in the recovery process. The demographic projections obtained through stochastic models confirmed that the recovery rates of C. rubrum can be strongly modulated depending on harvesting procedures. Thus, leaving the basal section of the colonies when harvesting to avoid total mortality largely enhances the resilience of C. rubrum populations and quickens their recovery. On the other hand, the high survival of harvested colonies and the significant biomass reduction indicated that abundance may not be an adequate metric to assess the conservation status of clonal organisms because it can underestimate harvesting effects. This study highlights the unsustainability of current harvesting practices

  6. AGE AND ORIGIN OF BASE- AND PRECIOUS-METAL VEINS OF THE COEUR D'ALENE MINING DISTRICT, IDAHO

    SciTech Connect

    Fleck, R J; Criss, R E; Eaton, G F; Cleland, R W; Wavra, C S; Bond, W D

    2000-11-07

    Ore-bearing quartz-carbonate veins of the Coeur d'Alene mining district yield {sup 87}Sr/{sup 86}Sr ratios of 0.74 to >1.60 for low-Rb/Sr, carbonate gangue minerals, similar to current ranges measured in Middle Proterozoic, high-Rb/Sr rocks of the Belt Supergroup. Stable-isotope and fluid-inclusion studies establish a genetic relationship between vein formation and metamorphic-hydrothermal systems of the region. These extraordinary {sup 87}Sr/{sup 86}Sr ratios require accumulation of radiogenic {sup 87}Sr in a high Rb/Sr system over an extended period prior to incorporation of Sr into the veins by hydrothermal processes. Evaluation of the age and composition of potential sources of highly radiogenic Sr indicates that the ore-bearing veins of the Coeur d'Alene district formed within the last 200 Ma from components scavenged from sedimentary and metasedimentary rocks of the Belt Supergroup, the primary host-rocks of the district. These results are consistent with a Cretaceous or Early Tertiary age for these veins. Pb-Zn deposits that yield Pb isotope, K-Ar, and Ar-Ar results indicative of a Proterozoic age probably formed during deposition or diagenesis of the Belt Supergroup at 1350-1500 Ma, possibly as Sullivan-type syngenetic deposits. K-Ar and Rb-Sr apparent ages and {delta}{sup 18}O values of Belt Supergroup rocks decrease southward from the Coeur d'Alene district toward the Idaho batholith, normal to the trends of metamorphic isograds, fold axes, foliation, and the major reverse faults of the district. Isoclinal folding, thrust faulting, high-temperature metamorphism, granitic plutonism, and regional-scale metamorphic-hydrothermal activity is documented in the region between 140 Ma and 45 Ma, but no similar combination of events is recognized for Late Proterozoic time. Combined with Sr results from the veins, the evidence strongly favors formation of the ore-bearing carbonate veins of the district by fluids related to a complex metamorphic-hydrothermal system during Cretaceous and/or early Tertiary time. Proterozoic Pb-Zn deposits were probably deformed, remobilized along younger structures, and incorporated into the younger hydrothermal deposits during this event.

  7. The Role of Silica in Precious Metal Supported Titania Hybrid Mesoporous Materials for Remediation and Energy Production

    NASA Astrophysics Data System (ADS)

    Kibombo, Harrison S.

    Semiconductor photocatalysis is an advanced oxidation process (AOP) that continues to show promise for the concomitant mineralization of non--biodegradable noxious and persistent organic pollutants (POPs) to environmentally benign products, and the splitting of water. This work examined the use of sol--gel chemistry as a viable approach for the incorporation of transparent silica (SiO2) matrix and/or platinum onto titania (TiO2) so as to optimize physico-chemical properties such as charge separation, crystallinity, surface area, and particle size. It was determined that crystallinity of anatase in the mixed oxide photocatalyst can be improved by the addition of simple non-polar aromatic co-solvents in the sol-gel route, and subsequently enhance the photocatalytic degradation of phenol under UV--light irradiation. The Pt of smaller particle sizes in Pt--TiO2--SiO 2 resulted in higher phenol degradation efficiencies under solar simulated conditions, irrespective of the synthesis method employed. The presence of Pt in the lowest oxidation state, Pt0, is crucial for enhanced phenol degradation whereas PtO2 (Pt4+) serves as a mild recombination center for photogenerated charge carriers rather than demonstrating total inactivity. The production of ·OH radicals was shown to be imperative for sustaining the degradation process. In the water splitting reaction for hydrogen production, the role of the crystallinity of anatase is reaffirmed when TiO2--SiO2 is used, as the surface defects present in the silica phase seem to serve as recombination centers. However, in Pt--TiO2 photocatalysts, the presence of Pt 0 or PtO2 in close contact with TiO2 (heterojunction) allows for more efficient electron propagation and facilitates minimization of electron--hole recombination, hence improved solar simulated photocatalytic hydrogen evolution. Extensive characterization of the photocatalysts were carried out by powder X--ray Diffraction (XRD), Nitrogen Physisorption Studies, Diffuse Reflectance Spectroscopy (DRS), Fourier Transform Infrared (FT--IR), Raman spectroscopy, CO-pulse chemisorption, X--ray Photoelectron Microscopy (XPS), Transmission Electron Microscopy (TEM), Electron Paramagnetic Resonance (EPR), and Energy Dispersive X--ray (EDX) spectroscopy. These techniques proved vital for establishing structure activity relationships, and as such provide insight to practitioners with simple techniques for the preparation of improved and economically viable photocatalysts for energy and environmental sustainability.

  8. Paragenesis and tectonic significance of base and precious metal occurrences along the San Andreas fault at Point Delgada, California.

    USGS Publications Warehouse

    McLaughlin, R.J.; Sorg, D.H.; Morton, J.L.; Theodore, T.G.; Meyer, C.E.; Delevaux, M.H.

    1985-01-01

    The mineralogy, geochemistry and origin of sulphide veins along cross faults in the San Andreas fault system are described and cited for a natural history of local plate tectonics and for 'a detailed understanding of the role of major strike-slip faults in the formation and tectonic translation of hydrothermal ore deposits'. -G.J.N.

  9. Stable isotope study of water-rock interaction and ore formation, Bayhorse base and precious metal district, Idaho

    USGS Publications Warehouse

    Seal, R.R., II; Rye, R.O.

    1992-01-01

    Whole-rock ??18O and ??D values from the Garden Creek Phyllite define an isotopically depleted zone (60 km2) around the Nevada Mountain stock and are the result of high-temperature interactions with ancient meteoric waters at water/rock ratios ranging from 0.002 to 0.09. Comparison of the ore fluid ??18OH2O and ??DH2O values with hypothetical waters equilibrated with the Garden Creek Phyllite indicates that the hydrothermal fluids must have also interacted with the basal dolomite of Bayhorse Creek, which underlies the phyllite. The ?? 13CCO2 values for the hydrothermal fluids also record a transition from early water/rock interactions that were dominated by the Garden Creek Phyllite to later interactions that were influenced significantly by the basal dolomite of Bayhorse Creek. The range of ??34S values may be interpreted as either a heterogeneous sedimentary source or mixed sedimentary-magmatic sources. -from Authors

  10. Geology and hydrothermal alteration at the Madh adh Dhahab epithermal precious-metal deposit, Kingdom of Saudi Arabia

    USGS Publications Warehouse

    Doebrich, J.L.; LeAnderson, J.P.

    1984-01-01

    Vein-related alteration consisting of quartz-sericite-pyrite, chloritic, argillic, and silicic halos was superimposed on broad zones of pervasive silicic, potassic, and argillic alteration that surrounds the rhyolite intrusive body. Quartz-sericite-pyrite alteration associated with the earliest stage of mineralization was followed by broad, pervasive, stratigraphically controlled potassic alteration. Subsequent mineralization was accompanied by quartz-sericitepyrite alteration and was followed by the main stage of mineralization that formed strong chloritic alteration halos. Development of broad zones and halos of argillic alteration also may have been related to the main stage of mineralization. Development of silicic halos was characteristic of the late stages of mineralization. Broad, pervasive propylitic alteration was then superimposed on all alteration types and represents cooling and inward encroachment of the hydrothermal system. All alteration, except the early silicic alteration is interpreted to have been related to circulating meteoric fluids heated by the rhyolite.

  11. Potential precious and strategic metals as by-products of uranium mineralized breccia pipes in northern Arizona

    SciTech Connect

    Wenrich, K.J.; Silberman, M.L.

    1984-07-01

    The development of caves within the Mississippian Redwall Limestone, accompanied by later upward stoping of overlying Paleozoic and Triassic rock, resulted in the formation of breccia pipes. Despite the depressed uranium market, some of these pipes are presently being mined for uranium. No brecciated rock within pipes has been observed above its normal stratigraphic position, nor is any volcanic rock associated in space or time with these pipes. Mineralized rock transects any strata from the Redwall Limestone to the Triassic Chinle Formation. Over 400 collapse structures, believed to represent breccia pipes (many with exposed breccia), have been mapped. Those with gamma radiation exceeding 2.5 times background (57 pipes) have been sampled (155 samples). Of these oxidized surface samples collected solely on the basis of radioactivity, 30% have Ag exceeding 10 ppm, some with up to 1150 ppm. Two samples of brecciated, oxidized sandstone with radioactivity exceeding 20 and 40 times background from this adit, and another sample of hematite-, malachite-, and chalcocite-impregnated sandstone from a higher level adit contained high concentrations of Au, Hg, Cd, and W, along with many elements commonly anomalous in mineralized breccia pipes from northern Arizona: Ag, As, Co, Cu, Mo, Ni, and Pb. The potential for economic recovery from breccia pipes of elements other than U, such as Ag, Au, Co, and Ni, should not be ignored as their concentrations are even more enhanced in unoxidized samples.

  12. Anomalous base and precious metals at oil-water contact in 1 Teague Well, Smackover Formation, southwest Arkansas

    SciTech Connect

    Price, P.E.; Lamore, F.E.; Kyle, J.R.; Kurtz, J.P.

    1988-02-01

    A core sample containing visible sulfide concentrations in an ooid grainstone unit of the Smackover Formation was collected from 8373 ft in the 1 Teague well, outpost McKamie field, Lafayette County, Arkansas. The sulfides are concentrated beneath a well-developed, high-amplitude stylolite that appears to have acted as a permeability barrier limiting sulfide development in the upper carbonate. Examination of the electric and descriptive log information for the interval revealed that: (1) the top of the sulfide zone corresponds to the existing oil-water contact, (2) scattered sulfides occur over an 84-ft interval beginning at 8373 ft, (3) an interval of greater than 10% porosity roughly coincides with the sulfide interval, and (4) an interval of hydrogen sulfide begins about 30 ft below the top of the sulfide interval and extends well below the last described sulfides. Assay results from a 1-ft composite sample showed that the core contains 36% zinc, 12% lead, and 888 ppm silver. The silver value equals about 26 oz/ton which is a high-grade ore in a mineable setting. The Zn/(Zn + Pb) ratio of 0.75 is typical of Gulf Coast salt dome hosted mineralization with ratios of 0.68 to 0.90. The Fe/(Fe + Zn) ratio on the other hand is 0.02 which is far below the 0.87 to 0.97 range of salt dome hosted sulfides. Petrographic examination indicates complex replacement and pore-filling mineralization. Minerals forming the late-stage mineralization assemblage include fine-grained replacement sphalerite-galena-acanthite-chalcopyrite-pyrite/marcasite-dolomite-coarse-grained sphalerite-calcite.

  13. NGR, XRD and TEM/SAED investigations on waste dumps materials with a view to recover precious metals

    NASA Astrophysics Data System (ADS)

    Udubasa, S. S.; Constantinescu, S.; Popescu-Pogrion, N.; Feder, M.; Udubasa, G.

    2010-03-01

    Two types of ores were selected for the investigation of the fate of the ore minerals during relatively long time of residence in the waste dumps (active mining: 25 years ago in the Badeanca Valley and some 50 years ago in the Valea lui Stan area). The pentametallic ores (Co-Ni-Bi-Ag-U) in the Leaota Mts. contain a great number of primary minerals of Cu, As etc. Although the waste dumps materials have whitish-yellowish colors their NGR spectra show the presence of iron minerals very finely dispersed. In the gold ores of Valea lui Stan deposit numerous minerals were identified, such as arsenopyrite, pyrite, pyrrhotite, etc., as major gold bearing sulfides. The waste dumps materials naturally show different mineral constituents, with clay minerals as major phases. Detailed NGR investigations show however Mössbauer spectra pointing out the presence of finely dispersed iron or iron-bearing minerals. Under supergene conditions gold is commonly sequestrated by iron hydroxydes; further TEM/SAED and XRD investigations are contributing to localize the gold. In some samples Mössbauer spectra resembling those of greigite have been obtained. Greigite is also a principal concentrator of gold under supergene conditions.

  14. Metal-Free Hydrosilylation Polymerization by Borane Catalyst.

    PubMed

    Kim, Dong Wook; Joung, Seewon; Kim, Jeung Gon; Chang, Sukbok

    2015-12-01

    The first example of metal-free hydrosilylation polymerization between dienes and disilanes is developed by using a borane catalyst, B(C6F5)3 to replace precious transition-metal-based systems. Under the easy-to-handle and mild conditions, a step-growth polymerization of two readily available diene and disilane units was achieved with high degrees of polymerization. Various combinations of dienes and disilanes produced polycarbosilanes with a broad range of structures and properties. PMID:26474096

  15. Institution Closures.

    ERIC Educational Resources Information Center

    Hayden, Mary F., Ed.; And Others

    1995-01-01

    This newsletter theme issue focuses on the need to accelerate the closing of institutions for people with mental retardation. Articles are by both current and former residents of institutions and by professionals, and include: "The Realities of Institutions" (Tia Nelis); "I Cry Out So That I Won't Go Insane" (Mary F. Hayden); "Trends in…

  16. Recycling metal scrap. (Latest citations from the EI compendex*plus database). Published Search

    SciTech Connect

    Not Available

    1993-11-01

    The bibliography contains citations concerning the processes, techniques, and benefits of recycling metal scrap. The recycling processes for aluminum, chromium, nickel, cobalt, lead, copper, and precious metals scrap are discussed. Recycling in the jewelry, electronics, milling, beverage, automotive, and aircraft industries is considered. Analyses of the current global scrap metal recycling trends are included. (Contains 250 citations and includes a subject term index and title list.)

  17. Preparing Future Geoscientists at the Critical High School-to-College Junction: Project METALS and the Value of Engaging Diverse Institutions to Serve Underrepresented Students

    NASA Astrophysics Data System (ADS)

    White, L. D.; Maygarden, D.; Serpa, L. F.

    2015-12-01

    Since 2010, the Minority Education Through Traveling and Learning in the Sciences (METALS) program, a collaboration among San Francisco State Univ., the Univ. of Texas at El Paso, the Univ. of New Orleans, and Purdue Univ., has created meaningful, field-based geoscience experiences for underrepresented minority high school students. METALS activities promote excitement about geoscience in field settings and foster mutual respect and trust among participants of different backgrounds and ethnicities. These gains are strengthened by the collective knowledge of the university partners and by faculty, graduate and undergraduate students, scientists, and science teachers who guide the field trips and who are committed to encouraging diversity in the geosciences. Through the student experiences it provides, METALS has helped shape and shift student attitudes and orientation toward geoscience, during and beyond their field experience, just as these students are poised at the critical juncture from high school to college. A review of the METALS findings and summative evaluation shows a distinct pattern of high to moderately high impact on most students in the various cohorts of the program. METALS, overall, was perceived by participants as a program that: (1) opens up opportunities for individuals who might not typically be able to experience science in outdoor settings; (2) offers high-interest geology content in field contexts, along with social and environmental connections; (3) promotes excitement about geology while encouraging the development of mutual respect, interdependence, and trust among individuals of different ethnicities; (4) influences the academic choices of students, in particular their choice of major and course selection in college. Summative data show that multiple aspects of this program were highly effective. Cross-university collaborations create a dynamic forum and a high-impact opportunity for students from different backgrounds to meet and develop

  18. Inclusions in precious Australian opals offer a unique access to Martian-like weathering processes

    NASA Astrophysics Data System (ADS)

    Roberts, Gemma; Rey, Patrice; Carter, Elizabeth

    2015-04-01

    Spectral signatures of the surface of Mars indicate a variety of hydrated minerals, including Al- and Fe/Mg-rich phyllosilicates, iron oxides, sulfates, and opaline silica. Their formation has been attributed to a long-lived low-temperature aqueous weathering history (e.g. Bishop et al., 2008; Ehlmann et al., 2013) followed by a period of intense acidic oxidative weathering (e.g. Carter et al., 2013). Very acidic weathering, driven by volcanic-derived sulfuric acid, is possible on a regional scale on Mars because of the lack of carbonate. On Earth, however, low-pH weathering on a regional scale is unusual because of the abundance of carbonate. Finding regional-scale Martian analogues on Earth is therefore a challenge. The Great Artesian Basin (GAB) in central Australia formed during the Early Cretaceous from the deposition of pyrite-rich volcaniclastic sediments in a cold, muddy, anoxic and shallow continental sea. Following mid-Cretaceous sea regression, a deep (~100 m) weathering profile recorded a protracted episode (~from 97 to 60 Ma) of oxidative weathering during continuous uplift and denudation, which stopped 60 myr ago. Since then, the weathering profile, which consists of Al- and Fe-rich phyllosilicates, iron oxides, and sulfates, has been constantly reworked. Interestingly, this profile hosts the bulk of the world's precious opal deposits. Since no opal deposit can be found in post-60 Ma rock formations, it is most likely that opal is part of the weathering profile developed during the drying out of central Australia. We analysed the mineral inclusions from six opal samples from the GAB to better document the early oxidative weathering. Using VNIR and Raman spectroscopy we were able to identify a variety of minerals including ferrihydrite, barite, gypsum and alunite replaced by goethite. This mineralogical assemblage is indicative of acidic oxidative conditions that points to Martian-like acidic weathering. We propose that acidity was derived from the

  19. Institutional Economics.

    ERIC Educational Resources Information Center

    Samuels, Warren J.

    1984-01-01

    Institutional economics remains a viable alternative approach to economics. It stresses power, technology, and a holistic and evolutionary approach while critiquing the neoclassical approach. General features of institutional economics are examined, and the work of institutionalists in specific areas is discussed. (RM)

  20. [Institutional Renewal].

    ERIC Educational Resources Information Center

    Brown, Peggy, Ed.

    1983-01-01

    The theme of this journal issue is "Institutional Renewal." Projects designed to address the issues of the 1980s at 18 colleges are described, and 15 definitions of institutional renewal are presented. Participating colleges were provided expert advice through the Association of American College's (AAC) Project Lodestar (renamed Consultation and…

  1. Institutional History.

    ERIC Educational Resources Information Center

    Kohlstedt, Sally Gregory

    1985-01-01

    Discusses recent work on scientific institutions in the United States, indicating that although historians have explored the origins of institutions, few have pursued these organizations into their later and perhaps equally complex years. Learned/professional organizations, museums, publications, and philanthropy are among the major topic areas…

  2. A hydrometallurgical process for recovering total metal values from waste monolithic ceramic capacitors.

    PubMed

    Prabaharan, G; Barik, S P; Kumar, B

    2016-06-01

    A hydrometallurgical process for recovering the total metal values from waste monolithic ceramic capacitors was investigated. The process parameters such as time, temperature, acid concentration, hydrogen peroxide concentration and other reagents (amount of zinc dust and sodium formate) were optimized. Base metals such as Ba, Ti, Sn, Cu and Ni are leached out in two stages using HCl in stage 1 and HCl with H2O2 in stage 2. More than 99% of leaching efficiency for base metals (Cu, Ni, Ba, Ti and Sn) was achieved. Precious metals such as Au and Pd are leached out using aquaregia and nitric acid was used for the leaching of Ag. Base metals (Ba, Ti, Sn, Cu and Ni) are recovered by selective precipitation using H2SO4 and NaOH solution. In case of precious metals, Au and Pd from the leach solution were precipitated out using sodium metabisulphite and sodium formate, respectively. Sodium chloride was used for the precipitation of Ag from leach solution. Overall recovery for base metals and precious metals are 95% and 92%, respectively. Based on the results of the present study, a process flow diagram was proposed for commercial application. PMID:27084106

  3. CSCAPES Institute

    SciTech Connect

    Alex Pothen

    2008-10-26

    We report on the progress made by researchers of the CSCAPES Institute at Old Dominion University for the years 2007 and 2008 in the areas of research, software creation, education and training, and outreach activities.

  4. Institutional Paralysis

    ERIC Educational Resources Information Center

    Yarmolinsky, Adam

    1975-01-01

    Institutional paralysis of higher education is the result of the disjunction between faculty and administration; the disjunction between substantive planning and bugetary decision-making; the disjunction between departmental structures and functional areas of university concern; and the disjunction between the theory of direct democracy and its…

  5. Institutional betrayal.

    PubMed

    Smith, Carly Parnitzke; Freyd, Jennifer J

    2014-09-01

    A college freshman reports a sexual assault and is met with harassment and insensitive investigative practices leading to her suicide. Former grade school students, now grown, come forward to report childhood abuse perpetrated by clergy, coaches, and teachers--first in trickles and then in waves, exposing multiple perpetrators with decades of unfettered access to victims. Members of the armed services elect to stay quiet about sexual harassment and assault during their military service or risk their careers by speaking up. A Jewish academic struggles to find a name for the systematic destruction of his people in Nazi Germany during the Holocaust. These seemingly disparate experiences have in common trusted and powerful institutions (schools, churches, military, government) acting in ways that visit harm upon those dependent on them for safety and well-being. This is institutional betrayal. The purpose of this article is to describe psychological research that examines the role of institutions in traumatic experiences and psychological distress following these experiences. We demonstrate the ways in which institutional betrayal has been left unseen by both the individuals being betrayed as well as the field of psychology and introduce means by which to identify and address this betrayal. PMID:25197837

  6. Institutional Bonding.

    ERIC Educational Resources Information Center

    Allard, M. June

    Institutional bonding was examined at a public, urban commuter college with exceptionally high attrition and visibly low morale. Changes in bonding and attrition were measured 6 years after a 2-year effort to develop school identity and student feelings of membership. It was found that a simple index of campus morale is provided by level of…

  7. Institution Morphisms

    NASA Technical Reports Server (NTRS)

    Goguen, Joseph; Rosu, Grigore; Norvig, Peter (Technical Monitor)

    2001-01-01

    Institutions formalize the intuitive notion of logical system, including both syntax and semantics. A surprising number of different notions of morphisim have been suggested for forming categories with institutions as objects, and a surprising variety of names have been proposed for them. One goal of this paper is to suggest a terminology that is both uniform and informative to replace the current rather chaotic nomenclature. Another goal is to investigate the properties and interrelations of these notions. Following brief expositions of indexed categories, twisted relations, and Kan extensions, we demonstrate and then exploit the duality between institution morphisms in the original sense of Goguen and Burstall, and the 'plain maps' of Meseguer, obtaining simple uniform proofs of completeness and cocompleteness for both resulting categories; because of this duality, we prefer the name 'comorphism' over 'plain map.' We next consider 'theoroidal' morphisms and comorphisims, which generalize signatures to theories, finding that the 'maps' of Meseguer are theoroidal comorphisms, while theoroidal morphisms are a new concept. We then introduce 'forward' and 'semi-natural' morphisms, and appendices discuss institutions for hidden algebra, universal algebra, partial equational logic, and a variant of order sorted algebra supporting partiality.

  8. EXTRACTION AND RECOVERY OF MERCURY AND LEAD FROM AQUEOUS WASTE STREAMS USING REDOX-ACTIVE LAYERED METAL CHALCOGENIDES

    EPA Science Inventory

    There are numerous practical reasons for selectively separating heavy metal ions of all types from aqueous media. A few obvious examples are the remediation of hazardous or radioactive waste, the remediation of contaminated groundwater, and the recovery of precious and/or toxic m...

  9. Metal-ion recycle technology for metal electroplating waste waters

    SciTech Connect

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

    1993-06-01

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

  10. Metal Preferences and Metallation*

    PubMed Central

    Foster, Andrew W.; Osman, Deenah; Robinson, Nigel J.

    2014-01-01

    The metal binding preferences of most metalloproteins do not match their metal requirements. Thus, metallation of an estimated 30% of metalloenzymes is aided by metal delivery systems, with ∼25% acquiring preassembled metal cofactors. The remaining ∼70% are presumed to compete for metals from buffered metal pools. Metallation is further aided by maintaining the relative concentrations of these pools as an inverse function of the stabilities of the respective metal complexes. For example, magnesium enzymes always prefer to bind zinc, and these metals dominate the metalloenzymes without metal delivery systems. Therefore, the buffered concentration of zinc is held at least a million-fold below magnesium inside most cells. PMID:25160626

  11. Hydrometallurgical Recovery of Metals from Large Printed Circuit Board Pieces

    PubMed Central

    Jadhav, U.; Hocheng, H.

    2015-01-01

    The recovery of precious metals from waste printed circuit boards (PCBs) is an effective recycling process. This paper presents a promising hydrometallurgical process to recover precious metals from waste PCBs. To simplify the metal leaching process, large pieces of PCBs were used instead of a pulverized sample. The chemical coating present on the PCBs was removed by sodium hydroxide (NaOH) treatment prior to the hydrometallurgical treatment. Among the leaching reagents examined, hydrochloric acid (HCl) showed great potential for the recovery of metals. The HCl-mediated leaching of waste PCBs was investigated over a range of conditions. Increasing the acid concentration decreased the time required for complete metal recovery. The shaking speed showed a pronounced positive effect on metal recovery, but the temperature showed an insignificant effect. The results showed that 1 M HCl recovered all of the metals from 4 cm × 4 cm PCBs at room temperature and 150 rpm shaking speed in 22 h. PMID:26415827

  12. Hydrometallurgical Recovery of Metals from Large Printed Circuit Board Pieces

    NASA Astrophysics Data System (ADS)

    Jadhav, U.; Hocheng, H.

    2015-09-01

    The recovery of precious metals from waste printed circuit boards (PCBs) is an effective recycling process. This paper presents a promising hydrometallurgical process to recover precious metals from waste PCBs. To simplify the metal leaching process, large pieces of PCBs were used instead of a pulverized sample. The chemical coating present on the PCBs was removed by sodium hydroxide (NaOH) treatment prior to the hydrometallurgical treatment. Among the leaching reagents examined, hydrochloric acid (HCl) showed great potential for the recovery of metals. The HCl-mediated leaching of waste PCBs was investigated over a range of conditions. Increasing the acid concentration decreased the time required for complete metal recovery. The shaking speed showed a pronounced positive effect on metal recovery, but the temperature showed an insignificant effect. The results showed that 1 M HCl recovered all of the metals from 4 cm × 4 cm PCBs at room temperature and 150 rpm shaking speed in 22 h.

  13. Efficient hydrogen evolution in transition metal dichalcogenides via a simple one-step hydrazine reaction.

    PubMed

    Cummins, Dustin R; Martinez, Ulises; Sherehiy, Andriy; Kappera, Rajesh; Martinez-Garcia, Alejandro; Schulze, Roland K; Jasinski, Jacek; Zhang, Jing; Gupta, Ram K; Lou, Jun; Chhowalla, Manish; Sumanasekera, Gamini; Mohite, Aditya D; Sunkara, Mahendra K; Gupta, Gautam

    2016-01-01

    Hydrogen evolution reaction is catalysed efficiently with precious metals, such as platinum; however, transition metal dichalcogenides have recently emerged as a promising class of materials for electrocatalysis, but these materials still have low activity and durability when compared with precious metals. Here we report a simple one-step scalable approach, where MoOx/MoS2 core-shell nanowires and molybdenum disulfide sheets are exposed to dilute aqueous hydrazine at room temperature, which results in marked improvement in electrocatalytic performance. The nanowires exhibit ∼100 mV improvement in overpotential following exposure to dilute hydrazine, while also showing a 10-fold increase in current density and a significant change in Tafel slope. In situ electrical, gate-dependent measurements and spectroscopic investigations reveal that hydrazine acts as an electron dopant in molybdenum disulfide, increasing its conductivity, while also reducing the MoOx core in the core-shell nanowires, which leads to improved electrocatalytic performance. PMID:27282871

  14. Efficient hydrogen evolution in transition metal dichalcogenides via a simple one-step hydrazine reaction

    NASA Astrophysics Data System (ADS)

    Cummins, Dustin R.; Martinez, Ulises; Sherehiy, Andriy; Kappera, Rajesh; Martinez-Garcia, Alejandro; Schulze, Roland K.; Jasinski, Jacek; Zhang, Jing; Gupta, Ram K.; Lou, Jun; Chhowalla, Manish; Sumanasekera, Gamini; Mohite, Aditya D.; Sunkara, Mahendra K.; Gupta, Gautam

    2016-06-01

    Hydrogen evolution reaction is catalysed efficiently with precious metals, such as platinum; however, transition metal dichalcogenides have recently emerged as a promising class of materials for electrocatalysis, but these materials still have low activity and durability when compared with precious metals. Here we report a simple one-step scalable approach, where MoOx/MoS2 core-shell nanowires and molybdenum disulfide sheets are exposed to dilute aqueous hydrazine at room temperature, which results in marked improvement in electrocatalytic performance. The nanowires exhibit ~100 mV improvement in overpotential following exposure to dilute hydrazine, while also showing a 10-fold increase in current density and a significant change in Tafel slope. In situ electrical, gate-dependent measurements and spectroscopic investigations reveal that hydrazine acts as an electron dopant in molybdenum disulfide, increasing its conductivity, while also reducing the MoOx core in the core-shell nanowires, which leads to improved electrocatalytic performance.

  15. Efficient hydrogen evolution in transition metal dichalcogenides via a simple one-step hydrazine reaction

    PubMed Central

    Cummins, Dustin R.; Martinez, Ulises; Sherehiy, Andriy; Kappera, Rajesh; Martinez-Garcia, Alejandro; Schulze, Roland K.; Jasinski, Jacek; Zhang, Jing; Gupta, Ram K.; Lou, Jun; Chhowalla, Manish; Sumanasekera, Gamini; Mohite, Aditya D.; Sunkara, Mahendra K.; Gupta, Gautam

    2016-01-01

    Hydrogen evolution reaction is catalysed efficiently with precious metals, such as platinum; however, transition metal dichalcogenides have recently emerged as a promising class of materials for electrocatalysis, but these materials still have low activity and durability when compared with precious metals. Here we report a simple one-step scalable approach, where MoOx/MoS2 core-shell nanowires and molybdenum disulfide sheets are exposed to dilute aqueous hydrazine at room temperature, which results in marked improvement in electrocatalytic performance. The nanowires exhibit ∼100 mV improvement in overpotential following exposure to dilute hydrazine, while also showing a 10-fold increase in current density and a significant change in Tafel slope. In situ electrical, gate-dependent measurements and spectroscopic investigations reveal that hydrazine acts as an electron dopant in molybdenum disulfide, increasing its conductivity, while also reducing the MoOx core in the core-shell nanowires, which leads to improved electrocatalytic performance. PMID:27282871

  16. Institute news

    NASA Astrophysics Data System (ADS)

    1999-11-01

    Joining the team A new member of staff has recently joined the Institute of Physics Education Department (Schools and Colleges) team. (Dr) Steven Chapman will have managerial responsibility for physics education issues in the 11 - 16 age range, particularly on the policy side. He will work closely with Mary Wood, who spends much of her time out and about doing the practical things to support physics education pre-16. Catherine Wilson will be spending more of her time working to support the Post-16 Physics Initiative but retains overall responsibility for the department. Steven graduated in Physics and Astronomy and then went on to do his doctorate at Sussex University. He stayed in the research field for a while, including a period at NPL. Then, having decided to train as a teacher, he taught for the last five years, most recently at a brand new school in Sutton where he was Head of Physics. Physics update Dates for `Physics Update' courses in 2000, intended for practising science teachers, are as follows: 1 - 3 April: Malvern College 9 - 10 June: Stirling University 8 - 10 July: York University 8 - 10 December: Oxford University The deadline for applications for the course to be held on 11 - 13 December 1999 at the School of Physics, Exeter University, is 12 November, so any late enquiries should be sent to Leila Solomon at The Institute of Physics, 76 Portland Place, London W1N 3DH (tel: 020 7470 4821) right away. Name that teacher! Late nominations are still welcome for the Teachers of Physics/Teachers of Primary Science awards for the year 2000. Closing date for nominations is `the last week in November'. Further details can be obtained from Catherine Wilson or Barbara Hill in the Institute's Education Department. Forward and back! The Education Group's one-day meeting on 13 November is accepting bookings until almost the last minute, so don't delay your application! The day is entitled `Post-16 physics: Looking forward, learning from the past' and it aims to

  17. Institute news

    NASA Astrophysics Data System (ADS)

    1999-11-01

    Joining the team A new member of staff has recently joined the Institute of Physics Education Department (Schools and Colleges) team. (Dr) Steven Chapman will have managerial responsibility for physics education issues in the 11 - 16 age range, particularly on the policy side. He will work closely with Mary Wood, who spends much of her time out and about doing the practical things to support physics education pre-16. Catherine Wilson will be spending more of her time working to support the Post-16 Physics Initiative but retains overall responsibility for the department. Steven graduated in Physics and Astronomy and then went on to do his doctorate at Sussex University. He stayed in the research field for a while, including a period at NPL. Then, having decided to train as a teacher, he taught for the last five years, most recently at a brand new school in Sutton where he was Head of Physics. Physics update Dates for `Physics Update' courses in 2000, intended for practising science teachers, are as follows: 1 - 3 April: Malvern College 9 - 10 June: Stirling University 8 - 10 July: York University 8 - 10 December: Oxford University The deadline for applications for the course to be held on 11 - 13 December 1999 at the School of Physics, Exeter University, is 12 November, so any late enquiries should be sent to Leila Solomon at The Institute of Physics, 76 Portland Place, London W1N 3DH (tel: 020 7470 4821) right away. Name that teacher! Late nominations are still welcome for the Teachers of Physics/Teachers of Primary Science awards for the year 2000. Closing date for nominations is `the last week in November'. Further details can be obtained from Catherine Wilson or Barbara Hill in the Institute's Education Department. Forward and back! The Education Group's one-day meeting on 13 November is accepting bookings until almost the last minute, so don't delay your application! The day is entitled `Post-16 physics: Looking forward, learning from the past' and it aims to

  18. Magnetotactic bacteria: promising biosorbents for heavy metals.

    PubMed

    Zhou, Wei; Zhang, Yanzong; Ding, Xiaohui; Liu, Yan; Shen, Fei; Zhang, Xiaohong; Deng, Shihuai; Xiao, Hong; Yang, Gang; Peng, Hong

    2012-09-01

    Magnetotactic bacteria (MTB), which can orient and migrate along a magnetic line of force due to intracellular nanosized magnetosomes, have been a subject of research in the medical field, in dating environmental changes, and in environmental remediation. This paper reviews the recent development of MTB as biosorbents for heavy metals. Ultrastructures and taxis of MTB are investigated. Adsorptions in systems of unitary and binary ions are highlighted, as well as adsorption conditions (temperature, pH value, biomass concentration, and pretreatments). The separation and desorption of MTB in magnetic separators are also discussed. A green method to produce metal nanoparticles is provided, and an energy-efficient way to recover precious metals is put forward during biosorption. PMID:22763846

  19. The characteristics of hydrothermal plumes observed in the Precious Stone Mountain hydrothermal field, the Galapagos spreading center

    NASA Astrophysics Data System (ADS)

    Chen, S.; Tao, C.; Li, H.; Zhou, J.; Deng, X.; Tao, W.; Zhang, G.; Liu, W.; He, Y.

    2014-12-01

    The Precious Stone Mountain hydrothermal field (PSMHF) is located on the southern rim of the Galapagos Microplate. It was found at the 3rd leg of the 2009 Chinese DY115-21 expedition on board R/V Dayangyihao. It is efficient to learn the distribution of hydrothermal plumes and locate the hydrothermal vents by detecting the anomalies of turbidity and temperature. Detecting seawater turbidity by MAPR based on deep-tow technology is established and improved during our cruises. We collected data recorded by MAPR and information from geological sampling, yielding the following results: (1)Strong hydrothermal turbidity and temperature anomalies were recorded at 1.23°N, southeast and northwest of PSMHF. According to the CTD data on the mooring system, significant temperature anomalies were observed over PSMHF at the depth of 1,470 m, with anomalies range from 0.2℃ to 0.4℃, which gave another evidence of the existence of hydrothermal plume. (2)At 1.23°N (101.4802°W/1.2305°N), the nose-shaped particle plume was concentrated at a depth interval of 1,400-1,600 m, with 200 m thickness and an east-west diffusion range of 500 m. The maximum turbidity anomaly (0.045 △NTU) was recorded at the depth of 1,500 m, while the background anomaly was about 0.01△NTU. A distinct temperature anomaly was also detected at the seafloor near 1.23°N. Deep-tow camera showed the area was piled up by hydrothermal sulfide sediments. (3) In the southeast (101.49°W/1.21°N), the thickness of hydrothermal plume was 300 m and it was spreading laterally at a depth of 1,500-1,800 m, for a distance about 800 m. The maximum turbidity anomaly of nose-shaped plume is about 0.04 △NTU at the depth of 1,600 m. Distinct temperature anomaly was also detected in the northwest (101.515°W/1.235°N). (4) Terrain and bottom current were the main factors controlling the distribution of hydrothermal plume. Different from the distribution of hydrothermal plumes on the mid-ocean ridges, which was mostly

  20. Stabilization of electrocatalytic metal nanoparticles at metal-metal oxide-graphene triple junction points.

    PubMed

    Kou, Rong; Shao, Yuyan; Mei, Donghai; Nie, Zimin; Wang, Donghai; Wang, Chongmin; Viswanathan, Vilayanur V; Park, Sehkyu; Aksay, Ilhan A; Lin, Yuehe; Wang, Yong; Liu, Jun

    2011-03-01

    Carbon-supported precious metal catalysts are widely used in heterogeneous catalysis and electrocatalysis, and enhancement of catalyst dispersion and stability by controlling the interfacial structure is highly desired. Here we report a new method to deposit metal oxides and metal nanoparticles on graphene and form stable metal-metal oxide-graphene triple junctions for electrocatalysis applications. We first synthesize indium tin oxide (ITO) nanocrystals directly on functionalized graphene sheets, forming an ITO-graphene hybrid. Platinum nanoparticles are then deposited, forming a unique triple-junction structure (Pt-ITO-graphene). Our experimental work and periodic density functional theory (DFT) calculations show that the supported Pt nanoparticles are more stable at the Pt-ITO-graphene triple junctions. Furthermore, DFT calculations suggest that the defects and functional groups on graphene also play an important role in stabilizing the catalysts. These new catalyst materials were tested for oxygen reduction for potential applications in polymer electrolyte membrane fuel cells, and they exhibited greatly enhanced stability and activity. PMID:21302925

  1. Study of a brittle and precious medieval rose-window by means of the integration of GPR, stress wave tests and infrared thermography

    NASA Astrophysics Data System (ADS)

    Nuzzo, L.; Masini, N.; Rizzo, E.

    2009-04-01

    The correct management and restoration of architectural monuments of high cultural interest requires a comprehensive understanding of their status of preservation, the detection of the building features, the localization of damages and possibly the identification of their causes, nature and extent. To this aim, in recent times there is a growing interest on non-destructive and non-invasive geophysical methods as an invaluable tool for correlating spatially the information gained through destructive tests, which are restricted to a few locations of the investigated structure, and to optimize the choice of their position in order to minimize their impact on the monument structural stability. Moreover, the integration of the classical geophysical techniques with emerging surface and subsurface sensing techniques (acoustics, thermography) provides a suitable methodology for a multi-scale assessment of the monument state of preservation and its material and building components, which is vital for addressing maintenance and restoration issues. The present case study focuses on the application of Ground Penetrating Radar (GPR), infrared thermography (IRT), sonic and ultrasonic tests to analyze a 13th century precious rose window in Southern Italy, affected by widespread decay and instability problems. The Cathedral of Troia (Apulia, Italy) is the masterpiece of the Apulian Romanesque architecture. Its façade is adorned with an astonishing 6 m diameter rose window consisting of 11 twin columns, in various stone and reused marbles, connected to a central oculus and to a ring of trapezoidal elements decorated with arched ribworks. Between the twin columns there are 11 triangular carved panels with different and strongly symbolic geometrical patterns. According to visual inspection, mineralogical and petrographic studies, different materials have been used for the different architectural elements: fine grained limestone for the central oculus, medium-fine grained calcarenite

  2. A Precious Opportunity

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This three-dimensional model superimposes the Mars Exploration Rover Opportunity on one of its potential targets, a scientific treasure chest of martian rocks contained within the landing site, a crater on Meridiani Planum, Mars. The rover is placed on the rock outcrop for scale. Opportunity has not yet visited these rocks; it is currently still on its lander. Scientists plan to use the tools on the rover's instrument deployment device, or robotic 'arm,' to examine these rocks, which are about 10 centimeters (4 inches) high and approximately 8 meters (26 feet) away from the rover. The image of the terrain was acquired on Sol, or martian day, 2 of Opportunity's journey. This model was created using data from the rover's panoramic camera and is displayed using software developed by NASA's Ames Research Center.

  3. Maintaining Precious Library Resources.

    ERIC Educational Resources Information Center

    Wiens, Janet

    2002-01-01

    Using the examples of libraries at Southeast Missouri State University and the University of North Texas, discusses the big-picture approach and extensive communication among all users necessary for library maintenance efforts. Addresses establishing a master plan, prioritizing projects, having the right staff, and communicating. (EV)

  4. A Precious Moment

    ERIC Educational Resources Information Center

    Kelner, Lenore Blank

    2005-01-01

    After twenty-three years of being a Teaching Artist, there is one residency that has continually haunted the author. It was an experience that reinforced the value of her work, validated the power of the arts in the classroom, and provoked deep personal reflection. The residency took place in 1999 at Park Street Elementary in a large Southern…

  5. Molecular metal-Nx centres in porous carbon for electrocatalytic hydrogen evolution

    NASA Astrophysics Data System (ADS)

    Liang, Hai-Wei; Brüller, Sebastian; Dong, Renhao; Zhang, Jian; Feng, Xinliang; Müllen, Klaus

    2015-08-01

    Replacement of precious platinum with efficient and low-cost catalysts for electrocatalytic hydrogen evolution at low overpotentials holds tremendous promise for clean energy devices. Here we report a novel type of robust cobalt-nitrogen/carbon catalyst for the hydrogen evolution reaction (HER) that is prepared by the pyrolysis of cobalt-N4 macrocycles or cobalt/o-phenylenediamine composites and using silica colloids as a hard template. We identify the well-dispersed molecular CoNx sites on the carbon support as the active sites responsible for the HER. The CoNx/C catalyst exhibits extremely high turnover frequencies per cobalt site in acids, for example, 0.39 and 6.5 s-1 at an overpotential of 100 and 200 mV, respectively, which are higher than those reported for other scalable non-precious metal HER catalysts. Our results suggest the great promise of developing new families of non-precious metal HER catalysts based on the controlled conversion of homogeneous metal complexes into solid-state carbon catalysts via economically scalable protocols.

  6. Hawaii Natural Energy Institute: Anual report, 1992

    SciTech Connect

    Not Available

    1992-12-31

    This progress report from the University of Hawaii at Manoa`s School of Ocean and Earth Science and Technology describes state of the art research in tapping the energy in and around the Hawaiian Islands. Researchers are seeking new ways of generating electricity and producing methanol from sugarcane waste and other biomass. They are finding ways to encourage the expanded use of methanol as a transportation fuel. They are creating innovative and cost-efficient methods of producing and storing hydrogen gas, considered the ``fuel of the future``. Researchers are also developing the techniques and technologies that will enable us to tap the unlimited mineral resources of the surrounding ocean. they are testing methods of using the oceans to reduce the carbon dioxide being discharged to the atmosphere. And they are mapping the strategies by which the seas can become a major source of food, precious metals, and space for living and for industry. The achievements described in this annual report can be attributed to the experience, creativity, painstaking study, perseverance, and sacrifices of our the dedicated corps of researchers.

  7. Hawaii Natural Energy Institute: Annual report, 1992

    SciTech Connect

    Not Available

    1992-01-01

    This progress report from the University of Hawaii at Manoa's School of Ocean and Earth Science and Technology describes state of the art research in tapping the energy in and around the Hawaiian Islands. Researchers are seeking new ways of generating electricity and producing methanol from sugarcane waste and other biomass. They are finding ways to encourage the expanded use of methanol as a transportation fuel. They are creating innovative and cost-efficient methods of producing and storing hydrogen gas, considered the fuel of the future''. Researchers are also developing the techniques and technologies that will enable us to tap the unlimited mineral resources of the surrounding ocean. they are testing methods of using the oceans to reduce the carbon dioxide being discharged to the atmosphere. And they are mapping the strategies by which the seas can become a major source of food, precious metals, and space for living and for industry. The achievements described in this annual report can be attributed to the experience, creativity, painstaking study, perseverance, and sacrifices of our the dedicated corps of researchers.

  8. Institutional Priority for Diversity at Christian Institutions

    ERIC Educational Resources Information Center

    Paredes-Collins, Kristin

    2009-01-01

    This evaluative study explored the relationship between institutional priority for diversity and minority enrollment at four schools within the Council for Christian Colleges and Universities, a consortium of Christian institutions. This institutional evaluation utilized public resources in order to gather descriptive data on minority enrollment…

  9. Hydrogen evolution by a metal-free electrocatalyst.

    PubMed

    Zheng, Yao; Jiao, Yan; Zhu, Yihan; Li, Lu Hua; Han, Yu; Chen, Ying; Du, Aijun; Jaroniec, Mietek; Qiao, Shi Zhang

    2014-01-01

    Electrocatalytic reduction of water to molecular hydrogen via the hydrogen evolution reaction may provide a sustainable energy supply for the future, but its commercial application is hampered by the use of precious platinum catalysts. All alternatives to platinum thus far are based on nonprecious metals, and, to our knowledge, there is no report about a catalyst for electrocatalytic hydrogen evolution beyond metals. Here we couple graphitic-carbon nitride with nitrogen-doped graphene to produce a metal-free hybrid catalyst, which shows an unexpected hydrogen evolution reaction activity with comparable overpotential and Tafel slope to some of well-developed metallic catalysts. Experimental observations in combination with density functional theory calculations reveal that its unusual electrocatalytic properties originate from an intrinsic chemical and electronic coupling that synergistically promotes the proton adsorption and reduction kinetics. PMID:24769657

  10. Hydrogen evolution by a metal-free electrocatalyst

    NASA Astrophysics Data System (ADS)

    Zheng, Yao; Jiao, Yan; Zhu, Yihan; Li, Lu Hua; Han, Yu; Chen, Ying; Du, Aijun; Jaroniec, Mietek; Qiao, Shi Zhang

    2014-04-01

    Electrocatalytic reduction of water to molecular hydrogen via the hydrogen evolution reaction may provide a sustainable energy supply for the future, but its commercial application is hampered by the use of precious platinum catalysts. All alternatives to platinum thus far are based on nonprecious metals, and, to our knowledge, there is no report about a catalyst for electrocatalytic hydrogen evolution beyond metals. Here we couple graphitic-carbon nitride with nitrogen-doped graphene to produce a metal-free hybrid catalyst, which shows an unexpected hydrogen evolution reaction activity with comparable overpotential and Tafel slope to some of well-developed metallic catalysts. Experimental observations in combination with density functional theory calculations reveal that its unusual electrocatalytic properties originate from an intrinsic chemical and electronic coupling that synergistically promotes the proton adsorption and reduction kinetics.

  11. Institute Study Report

    NASA Technical Reports Server (NTRS)

    Whitaker, Ann; Steadman, Jackie; Little, Sally; Underwood, Debra; Blackman, Mack; Simonds, Judy

    1997-01-01

    This report documents a study conducted by the MSFC working group on Institutes in 1995 on the structure, organization and business arrangements of Institutes at a time when the agency was considering establishing science institutes. Thirteen institutes, ten science centers associated with the state of Georgia, Stanford Research Institute (SRI), and IIT Research Institute (IITRI), and general data on failed institutes were utilized to form this report. The report covers the working group's findings on institute mission, structure, director, board of directors/advisors, the working environment, research arrangements, intellectual property rights, business management, institute funding, and metrics.

  12. Challenges to achievement of metal sustainability in our high-tech society

    SciTech Connect

    Izatt, Reed M.; Izatt, Steven R.; Bruening, Ronald L.; Izatt, Neil; Moyer, Bruce A

    2014-01-01

    Achievement of sustainability in metal life cycles from mining of virgin ore to consumer and industrial devices to end-of-life products requires greatly increased recycling and improved processing of metals. Electronic and other high-tech products containing precious, toxic, and specialty metals usually have short lifetimes and low recycling rates. Products containing these metals generally are incinerated, discarded as waste in landfills, or dismantled in informal recycling using crude and environmentally irresponsible procedures. Low metal recycling rates coupled with increasing demand for products containing them necessitate increased mining with attendant environmental, health, energy, water, and carbon-footprint consequences. In this tutorial review, challenges to achieving metal sustainability in present high-tech society are presented; health, environmental, and economic incentives for various stakeholders to improve metal sustainability are discussed; a case for technical improvements in separations technology, especially employing molecular recognition, is given; and global consequences of continuing on the present path are examined.

  13. PRECIOUS METALS IN SDSS QUASAR SPECTRA. I. TRACKING THE EVOLUTION OF STRONG, 1.5 < z < 4.5 C IV ABSORBERS WITH THOUSANDS OF SYSTEMS

    SciTech Connect

    Cooksey, Kathy L.; Kao, Melodie M.; Simcoe, Robert A.; O'Meara, John M.; Prochaska, J. Xavier E-mail: mkao@caltech.edu E-mail: jomeara@smcvt.edu

    2013-01-20

    We have vastly increased the C IV statistics at intermediate redshift by surveying the thousands of quasars in the Sloan Digital Sky Survey (SDSS) Data-Release 7. We visually verified over 16,000 C IV systems with 1.46 < z < 4.55-a sample size that renders Poisson error negligible. Detailed Monte Carlo simulations show that we are approximately 50% complete down to rest equivalent widths W {sub r} Almost-Equal-To 0.6 A. We analyzed the sample as a whole and in 10 small redshift bins with approximately 1500 doublets each. The equivalent width frequency distributions f(W {sub r}) were well modeled by an exponential, with little evolution in shape. In contrast with previous studies that modeled the frequency distribution as a single power law, the fitted exponential gives a finite mass density for the C IV ions. The comoving line density dN{sub CIV}/dX evolved smoothly with redshift, increasing by a factor of 2.37 {+-} 0.09 from z = 4.55-1.96, then plateauing at dN{sub CIV}/dX{approx}0.34 for z = 1.96-1.46. Comparing our SDSS sample with z < 1 (ultraviolet) and z > 5 (infrared) surveys, we see an approximately 10-fold increase in dN{sub CIV}/dX over z Almost-Equal-To 6 {yields} 0, for W {sub r} {>=} 0.6 A. This suggests a monotonic and significant increase in the enrichment of gas outside galaxies over the 12 Gyr lifetime of the universe.

  14. Precious Metals in SDSS Quasar Spectra. I. Tracking the Evolution of Strong, 1.5 < z < 4.5 C IV Absorbers with Thousands of Systems

    NASA Astrophysics Data System (ADS)

    Cooksey, Kathy L.; Kao, Melodie M.; Simcoe, Robert A.; O'Meara, John M.; Prochaska, J. Xavier

    2013-01-01

    We have vastly increased the C IV statistics at intermediate redshift by surveying the thousands of quasars in the Sloan Digital Sky Survey (SDSS) Data-Release 7. We visually verified over 16,000 C IV systems with 1.46 < z < 4.55—a sample size that renders Poisson error negligible. Detailed Monte Carlo simulations show that we are approximately 50% complete down to rest equivalent widths W r ≈ 0.6 Å. We analyzed the sample as a whole and in 10 small redshift bins with approximately 1500 doublets each. The equivalent width frequency distributions f(W r) were well modeled by an exponential, with little evolution in shape. In contrast with previous studies that modeled the frequency distribution as a single power law, the fitted exponential gives a finite mass density for the C IV ions. The comoving line density d {N}_{{C IV}}/dX evolved smoothly with redshift, increasing by a factor of 2.37 ± 0.09 from z = 4.55-1.96, then plateauing at d {N}_{{C IV}}/dX≈ 0.34 for z = 1.96-1.46. Comparing our SDSS sample with z < 1 (ultraviolet) and z > 5 (infrared) surveys, we see an approximately 10-fold increase in d {N}_{{C IV}}/dX over z ≈ 6 → 0, for W r >= 0.6 Å. This suggests a monotonic and significant increase in the enrichment of gas outside galaxies over the 12 Gyr lifetime of the universe.

  15. Precious metals in SDSS quasar spectra. II. Tracking the evolution of strong, 0.4 < z < 2.3 Mg II absorbers with thousands of systems

    SciTech Connect

    Seyffert, Eduardo N.; Simcoe, Robert A.; Cooksey, Kathy L.; O'Meara, John M.; Kao, Melodie M.; Prochaska, J. Xavier E-mail: simcoe@space.mit.edu E-mail: jomeara@smcvt.edu E-mail: xavier@ucolick.org

    2013-12-20

    We have performed an analysis of over 34,000 Mg II doublets at 0.36 < z < 2.29 in Sloan Digital Sky Survey (SDSS) Data Release 7 quasar spectra; the catalog, advanced data products, and tools for analysis are publicly available. The catalog was divided into 14 small redshift bins with roughly 2500 doublets in each and from Monte Carlo simulations, we estimate 50% completeness at rest equivalent width W {sub r} ≈ 0.8 Å. The equivalent width frequency distribution is described well by an exponential model at all redshifts, and the distribution becomes flatter with increasing redshift, i.e., there are more strong systems relative to weak ones. Direct comparison with previous SDSS Mg II surveys reveals that we recover at least 70% of the doublets in these other catalogs, in addition to detecting thousands of new systems. We discuss how these surveys came by their different results, which qualitatively agree but because of the very small uncertainties, differ by a statistically significant amount. The estimated physical cross section of Mg II-absorbing galaxy halos increased approximately threefold from z = 0.4 to z = 2.3, while the W {sub r} ≥ 1 Å absorber line density, dN{sub MgII}/dX, grew by roughly 45%. Finally, we explore the different evolution of various absorber populations—damped Lyα absorbers, Lyman limit systems, strong C IV absorbers, and strong and weaker Mg II systems—across cosmic time (0 < z < 6).

  16. Proton transfer dynamics control the mechanism of O2 reduction by a non-precious metal electrocatalyst.

    PubMed

    Tse, Edmund C M; Barile, Christopher J; Kirchschlager, Nicholas A; Li, Ying; Gewargis, John P; Zimmerman, Steven C; Hosseini, Ali; Gewirth, Andrew A

    2016-07-01

    Many chemical and biological processes involve the transfer of both protons and electrons. The complex mechanistic details of these proton-coupled electron transfer (PCET) reactions require independent control of both electron and proton transfer. In this report, we make use of lipid-modified electrodes to modulate proton transport to a Cu-based catalyst that facilitates the O2 reduction reaction (ORR), a PCET process important in fuel cells and O2 reduction enzymes. By quantitatively controlling the kinetics of proton transport to the catalyst, we demonstrate that undesired side products such as H2O2 and O2(-) arise from a mismatch between proton and electron transfer rates. Whereas fast proton kinetics induce H2O2 formation and sluggish proton flux produces O2(-), proton transfer rates commensurate with O-O bond breaking rates ensure that only the desired H2O product forms. This fundamental insight aids in the development of a comprehensive framework for understanding the ORR and PCET processes in general. PMID:27135859

  17. Precious Metals in SDSS Quasar Spectra II: Uber Analysis of the Full, 1.6 < z < 3.6 CIV Distribution

    NASA Astrophysics Data System (ADS)

    Cooksey, Kathy; Simcoe, R. A.; D'Odorico, V.; O'Meara, J.; Prochaska, J. X.; Kao, M.; Calura, F.; Cristiani, S.

    2013-01-01

    The CIV doublet has proven to be an important tracer of the IGM and its evolution from z = 6 to 0. We vastly improved the 1.5 < z < 4.5 CIV statistics by surveying the thousands of SDSS DR7 quasar spectra, resulting in a catalog with more than 15,000 systems (Cooksey et al. 2012). We showed that the number density of CIV absorbers more than doubled in the almost three-billion years probed by the SDSS survey. Statistically, all of these strong CIV systems are consistent with UV-selected galaxies having CIV-absorbing halos, extending out to 100 physical kpc. We also measured an exponential distribution of CIV strengths. Previous smaller, more sensitive surveys found the distribution to be fit best by a power law. Now we combine the SDSS systems with one of these more sensitive surveys (D'Odorico et al. 2010) in order to model the full distribution of CIV absorbers.

  18. Base- and precious-metal deposits in the Basin and Range of Southern California and Southern Nevada - Metallogenic implications of lead isotope studies

    USGS Publications Warehouse

    Church, S.E.; Cox, D.P.; Wooden, J.L.; Tingley, J.V.; Vaughn, R.B.

    2005-01-01

    Southern California and southern Nevada contain abundant lead-zinc deposits with strikingly different characteristics. On the west, the Darwin Terrane contains abundant Jurassic and Cretaceous intrusions surrounded by lead-zinc skarn and replacement deposits rich in pyrite and manganese minerals. The Tecopa Terrane is east of the Darwin Terrane and contains some lead deposits that are hosted by the Proterozoic Noonday Dolomite. These lead deposits have no consistent relation to igneous rocks; they contain mainly galena, and are devoid of pyrite and manganese minerals. Other skarn and vein deposits in the Ivanpah and Tecopa districts are more closely associated with igneous rocks. Mississippi Valley type lead-zinc deposits are present still farther to the east in the Goodsprings Terrane in Nevada. These deposits are hosted by breccias formed below the Mississippian-Pennsylvanian unconformity and are unrelated to igneous rocks. Deposits in the Darwin Terrane have lead isotopic signatures that lie along a mantle-sediment mixing line indicating that they formed in a continental arc setting analogous to that for the plutons in the Sierra Nevada batholith [Chen, J.H. and Tilton, G.R., 1991. Application of lead and strontium isotopic relationships to the petrogenesis of granitoid rocks, central Sierra Nevada batholith, California. Geological Society of America Bulletin 103, 439-447]. Encroachment of this continental arc on the North American continent in the eastern part of the Darwin Terrane resulted in a lead isotopic signature that is like that of the strongly contaminated plutons [Chen, J.H. and Tilton, G.R., 1991. Application of lead and strontium isotopic relationships to the petrogenesis of granitoid rocks, central Sierra Nevada batholith, California. Geological Society of America Bulletin 103, 439-447]. Many deposits from the Inyo Mountains on east side of the Owens Valley have lead isotopic signatures that reflect this encroachment. To the east in the Tecopa Terrane, encroachment of the continental arc on the Mojave crust resulted in partial melting of 1.7 Ga amphibolite and granulite facies rocks to produce the plutons and mineral deposits associated with plutons in this terrane. Lead from deposits in this terrane hosted in the Proterozoic Noonday Dolomite and associated rocks have a lead isotope signature that reflects hydrothermal circulation of fluids in the Mojave supracrustal rocks. The boundary between the Darwin Terrane and the Tecopa Terrane lies just west of the Ash Valley-Panamint Range Fault and is bounded by the Towne Fault on the north and the Garlock Fault on the south. Lead isotopic data from the Goodsprings district in southwestern Nevada, east of the Tecopa Terrane, form a 1.45 Ga linear array that is indicative of Mississippi Valley type mineralization. Although we have no independent evidence of the timing of the tectonic events that formed these deposits, it is likely that all formed as a result of the Mesozoic collision of the Panthalassen crust with the North American continent. ?? 2005 Elsevier B.V. All rights reserved.

  19. Animal carcass wastewater treatment and bioelectricity generation in up-flow tubular microbial fuel cells: effects of HRT and non-precious metallic catalyst.

    PubMed

    Li, Xiaohu; Zhu, Nengwu; Wang, Yun; Li, Ping; Wu, Pingxiao; Wu, Jinhua

    2013-01-01

    Animal carcass wastewater (ACW) is a kind of typical high concentration organic wastewater. Up-flow tubular air cathode microbial fuel cells (MFCs) were constructed using 0, 4.0 and 8.0mg/cm(2) MnO(2) as cathodic catalyst, respectively (MFC-0, MFC-4 and MFC-8) to test the feasibility of bioelectricity production from ACW. After a start-up period of around 55 d, when hydraulic retention time (HRT) was set at 3d, MFC-4 showed best bioelectricity performance with the maximum power density of 2.19 W/m(3) and minimum internal resistance of 30.3 Ω, as compared to MFC-0 (1.14 W/m(3), 62.6 Ω) and MFC-8 (1.49 W/m(3), 34.5 Ω). Chemical oxygen demand (COD) and nitrate removal efficiencies of MFC-4 were 50.66% and 79.76%, respectively. Switching HRT from 3d to 6d, COD and nitrate removal efficiencies sped up while the increase rates of ammonia slowed down. The results demonstrated that ACW could be the fuel of MFCs to generate bioelectricity. PMID:23201528

  20. Precious Metals in SDSS Quasar Spectra. II. Tracking the Evolution of Strong, 0.4 < z < 2.3 Mg II Absorbers with Thousands of Systems

    NASA Astrophysics Data System (ADS)

    Seyffert, Eduardo N.; Cooksey, Kathy L.; Simcoe, Robert A.; O'Meara, John M.; Kao, Melodie M.; Prochaska, J. Xavier

    2013-12-01

    We have performed an analysis of over 34,000 Mg II doublets at 0.36 < z < 2.29 in Sloan Digital Sky Survey (SDSS) Data Release 7 quasar spectra; the catalog, advanced data products, and tools for analysis are publicly available. The catalog was divided into 14 small redshift bins with roughly 2500 doublets in each and from Monte Carlo simulations, we estimate 50% completeness at rest equivalent width W r ≈ 0.8 Å. The equivalent width frequency distribution is described well by an exponential model at all redshifts, and the distribution becomes flatter with increasing redshift, i.e., there are more strong systems relative to weak ones. Direct comparison with previous SDSS Mg II surveys reveals that we recover at least 70% of the doublets in these other catalogs, in addition to detecting thousands of new systems. We discuss how these surveys came by their different results, which qualitatively agree but because of the very small uncertainties, differ by a statistically significant amount. The estimated physical cross section of Mg II-absorbing galaxy halos increased approximately threefold from z = 0.4 to z = 2.3, while the W r >= 1 Å absorber line density, d {N}_{{Mg}\\,\\scriptsize{II}}/d X, grew by roughly 45%. Finally, we explore the different evolution of various absorber populations—damped Lyα absorbers, Lyman limit systems, strong C IV absorbers, and strong and weaker Mg II systems—across cosmic time (0 < z < 6).

  1. A Cleaner Process for Selective Recovery of Valuable Metals from Electronic Waste of Complex Mixtures of End-of-Life Electronic Products.

    PubMed

    Sun, Zhi; Xiao, Y; Sietsma, J; Agterhuis, H; Yang, Y

    2015-07-01

    In recent years, recovery of metals from electronic waste within the European Union has become increasingly important due to potential supply risk of strategic raw material and environmental concerns. Electronic waste, especially a mixture of end-of-life electronic products from a variety of sources, is of inherently high complexity in composition, phase, and physiochemical properties. In this research, a closed-loop hydrometallurgical process was developed to recover valuable metals, i.e., copper and precious metals, from an industrially processed information and communication technology waste. A two-stage leaching design of this process was adopted in order to selectively extract copper and enrich precious metals. It was found that the recovery efficiency and extraction selectivity of copper both reached more than 95% by using ammonia-based leaching solutions. A new electrodeposition process has been proven feasible with 90% current efficiency during copper recovery, and the copper purity can reach 99.8 wt %. The residue from the first-stage leaching was screened into coarse and fine fractions. The coarse fraction was returned to be releached for further copper recovery. The fine fraction was treated in the second-stage leaching using sulfuric acid to further concentrate precious metals, which could achieve a 100% increase in their concentrations in the residue with negligible loss into the leaching solution. By a combination of different leaching steps and proper physical separation of light materials, this process can achieve closed-loop recycling of the waste with significant efficiency. PMID:26061274

  2. Recyclable Earth-Abundant Metal Nanoparticle Catalysts for Selective Transfer Hydrogenation of Levulinic Acid to Produce γ-Valerolactone.

    PubMed

    Gowda, Ravikumar R; Chen, Eugene Y-X

    2016-01-01

    Nanoparticles (NPs) derived from earth-abundant metal(0) carbonyls catalyze conversion of bio-derived levulinic acid into γ-valerolactone in up to 93% isolated yield. This sustainable and green route uses non-precious metal catalysts and can be performed in aqueous or ethanol solution without using hydrogen gas as the hydrogen source. Generation of metal NPs using microwave irradiation greatly enhances the rate of the conversion, enables the use of ethanol as both solvent and hydrogen source without forming the undesired ethyl levulinate, and affords recyclable polymer-stabilized NPs. PMID:26735911

  3. Recovery of high-value metals from geothermal sites by biosorption and bioaccumulation.

    PubMed

    Lo, Yung-Chung; Cheng, Chieh-Lun; Han, Yin-Lung; Chen, Bor-Yann; Chang, Jo-Shu

    2014-05-01

    Generation of geothermal energy is associated with a significant amount of geothermal fluids, which may be abundant in high-value metals, such as lithium, cesium, rubidium, and other precious and rare earth metals. The recovery of high-value metals from geothermal fluids would thus have both economic and environmental benefits. The conventional technologies applied to achieve this are mostly physicochemical, which may be energy intensive, pose the risk of secondary pollution whilst being inefficient in recovering metals from dilute solutions. Biological methods, based on biosorption or bioaccumulation, have recently emerged as alternative approaches, as they are more environmentally friendly, cost effective, and suitable for treating wastewater with dilute metal contents. This article provides a comprehensive review of the related biological technologies used to recover the high-value metals present in geothermal fluids as well as critical discussion on the key issues that are often used to evaluate the effectiveness of those methods. PMID:24581863

  4. Study of a brittle and precious medieval rose-window by means of the integration of GPR, stress wave tests and infrared thermography

    NASA Astrophysics Data System (ADS)

    Nuzzo, L.; Masini, N.; Rizzo, E.

    2009-04-01

    The correct management and restoration of architectural monuments of high cultural interest requires a comprehensive understanding of their status of preservation, the detection of the building features, the localization of damages and possibly the identification of their causes, nature and extent. To this aim, in recent times there is a growing interest on non-destructive and non-invasive geophysical methods as an invaluable tool for correlating spatially the information gained through destructive tests, which are restricted to a few locations of the investigated structure, and to optimize the choice of their position in order to minimize their impact on the monument structural stability. Moreover, the integration of the classical geophysical techniques with emerging surface and subsurface sensing techniques (acoustics, thermography) provides a suitable methodology for a multi-scale assessment of the monument state of preservation and its material and building components, which is vital for addressing maintenance and restoration issues. The present case study focuses on the application of Ground Penetrating Radar (GPR), infrared thermography (IRT), sonic and ultrasonic tests to analyze a 13th century precious rose window in Southern Italy, affected by widespread decay and instability problems. The Cathedral of Troia (Apulia, Italy) is the masterpiece of the Apulian Romanesque architecture. Its façade is adorned with an astonishing 6 m diameter rose window consisting of 11 twin columns, in various stone and reused marbles, connected to a central oculus and to a ring of trapezoidal elements decorated with arched ribworks. Between the twin columns there are 11 triangular carved panels with different and strongly symbolic geometrical patterns. According to visual inspection, mineralogical and petrographic studies, different materials have been used for the different architectural elements: fine grained limestone for the central oculus, medium-fine grained calcarenite

  5. Global mining risk footprint of critical metals necessary for low-carbon technologies: the case of neodymium, cobalt, and platinum in Japan.

    PubMed

    Nansai, Keisuke; Nakajima, Kenichi; Kagawa, Shigemi; Kondo, Yasushi; Shigetomi, Yosuke; Suh, Sangwon

    2015-02-17

    Meeting the 2-degree global warming target requires wide adoption of low-carbon energy technologies. Many such technologies rely on the use of precious metals, however, increasing the dependence of national economies on these resources. Among such metals, those with supply security concerns are referred to as critical metals. Using the Policy Potential Index developed by the Fraser Institute, this study developed a new footprint indicator, the mining risk footprint (MRF), to quantify the mining risk directly and indirectly affecting a national economy through its consumption of critical metals. We formulated the MRF as a product of the material footprint (MF) of the consuming country and the mining risks of the countries where the materials are mined. A case study was conducted for the 2005 Japanese economy to determine the MF and MRF for three critical metals essential for emerging energy technologies: neodymium, cobalt and platinum. The results indicate that in 2005 the MFs generated by Japanese domestic final demand, that is, the consumption-based metal output of Japan, were 1.0 × 10(3) t for neodymium, 9.4 × 10(3) t for cobalt, and 2.1 × 10 t for platinum. Export demand contributes most to the MF, accounting for 3.0 × 10(3) t, 1.3 × 10(5) t, and 3.1 × 10 t, respectively. The MRFs of Japanese total final demand (domestic plus export) were calculated to be 1.7 × 10 points for neodymium, 4.5 × 10(-2) points for cobalt, and 5.6 points for platinum, implying that the Japanese economy is incurring a high mining risk through its use of neodymium. This country's MRFs are all dominated by export demand. The paper concludes by discussing the policy implications and future research directions for measuring the MFs and MRFs of critical metals. For countries poorly endowed with mineral resources, adopting low-carbon energy technologies may imply a shifting of risk from carbon resources to other natural resources, in particular critical metals, and a trade

  6. Surface Science Studies of Strong Metal-Oxide Interactions on Model Catalysts

    NASA Astrophysics Data System (ADS)

    Bowker, Michael; Bennett, Roger A.

    Here we report on recent model studies of a phenomenon known in catalysis as the “Strong Metal-Support Interaction” (SMSI for short). Decoration of the surfaces of precious metal single crystals, films, and nanoparticles supported on titania produces beautiful long-range ordered structures which can often be resolved at atomic resolution using scanning tunneling microscopy (STM). Such surfaces show reduced binding for CO and effectively lower the activity of the surface. Consideration is given to the cause and composition of the surface layer, that is, whether it is a kind of intermetallic layer, or is simply a thin layer of titanium (sub-)oxide.

  7. Functionalized magnetite particles for adsorption of colloidal noble metal nanoparticles.

    PubMed

    Lopes, Joana L; Marques, Karine L; Girão, Ana V; Pereira, Eduarda; Trindade, Tito

    2016-08-01

    Magnetite (inverse spinel type) particles have been surface-modified with siliceous shells enriched in dithiocarbamate groups. The deposition of colloidal noble metal nanoparticles (Au, Ag, Pt, Pd) onto the modified magnetites can be performed by treating the respective hydrosols with the magnetic sorbents, thus allowing their uptake from water under a magnetic gradient. In particular, for Au colloids, these magnetic particles are very efficient sorbents that we ascribe to the strong affinity of sulfur-containing groups at the magnetite surfaces for this metal. Considering the extensive use of Au colloids in laboratorial and industrial contexts, the approach described here might have an impact on the development of nanotechnologies to recover this precious metal. En route to these findings, we varied several operational parameters in order to investigate this strategy as a new bottom-up assembly method for producing plasmonic-magnetic nanoassemblies. PMID:27156089

  8. Metals removal and recovery in bioelectrochemical systems: A review.

    PubMed

    Nancharaiah, Y V; Venkata Mohan, S; Lens, P N L

    2015-11-01

    Metal laden wastes and contamination pose a threat to ecosystem well being and human health. Metal containing waste streams are also a valuable resource for recovery of precious and scarce elements. Although biological methods are inexpensive and effective for treating metal wastewaters and in situ bioremediation of metal(loid) contamination, little progress has been made towards metal(loid) recovery. Bioelectrochemical systems are emerging as a new technology platform for removal and recovery of metal ions from metallurgical wastes, process streams and wastewaters. Biodegradation of organic matter by electroactive biofilms at the anode has been successfully coupled to cathodic reduction of metal ions. Until now, leaching of Co(II) from LiCoO2 particles, and removal of metal ions i.e. Co(III/II), Cr(VI), Cu(II), Hg(II), Ag(I), Se(IV), and Cd(II) from aqueous solutions has been demonstrated. This article reviews the state of art research of bioelectrochemical systems for removal and recovery of metal(loid) ions and pertaining removal mechanisms. PMID:26116446

  9. National Institutes of Health

    MedlinePlus

    ... Stem Cell Information OppNet NIDB NIH Blueprint for Neuroscience Research Institutes at NIH List of Institutes, Centers & ... be prevented. Pneumonia Causes, symptoms, diagnosis and treatments. Learning Disabilities Early interventions offer help with learning problems. ...

  10. Texas Heart Institute

    MedlinePlus

    ... Join us! James T. Willerson MD Cardiovascular Seminar Texas Heart Institute Journal Scientific Publications Library & Learning Resources ... Education 12th Annual Diabetes Symposium September 17, 2016 Texas Heart Institute Program Director: Mandeep Bajaj, MD Clinical ...

  11. Swimmer-Training Institutions

    ERIC Educational Resources Information Center

    O'Donnell, R. W.

    1972-01-01

    This satirical essay proposes an institution of higher learning that would prepare students to become swimmers" and swimming instructors. Curriculum, teaching methods, student selection and evaluation are modelled on certain contemporary teacher-training institutes. (PD)

  12. Canadian institute honours Hawking

    NASA Astrophysics Data System (ADS)

    Durrani, Matin

    2009-11-01

    The Perimeter Institute for Theoretical Physics in Waterloo, Canada, has announced that a major new extension to its campus will be known as the Stephen Hawking Centre. The extension, which is currently being built, is due to open in 2011 and will double the size of the institute. It will also provide a home for the institute's Masters students, the first of whom joined the Perimeter Institute this autumn as part of its Perimeter Scholars international programme.

  13. Transition-Metal Doped Ceria Microspheres with Nanoporous Structures for CO Oxidation.

    PubMed

    Zhou, Lin; Li, Xiaoxiao; Yao, Ze; Chen, Zhuwen; Hong, Mei; Zhu, Rongshu; Liang, Yongye; Zhao, Jing

    2016-01-01

    Catalytic oxidation of carbon monoxide (CO) is of great importance in many different fields of industry. Until now it still remains challenging to use non-noble metal based catalysts to oxidize CO at low temperature. Herein, we report a new class of nanoporous, uniform, and transition metal-doped cerium (IV) oxide (ceria, CeO2) microsphere for CO oxidation catalysis. The porous and uniform microsphere is generated by sacrificed polymer template. Transition-metals, like Cu, Co, Ni, Mn and Fe, were doped into CeO2 microspheres. The combination of hierarchical structure and metal doping afford superior catalytic activities of the doped ceria microspheres, which could pave a new way to advanced non-precious metal based catalysts for CO oxidation. PMID:27030159

  14. UNEXPECTED PRESENCE OF SOLUTE-FREE ZONES AT METAL-WATER INTERFACES.

    PubMed

    Chai, B; Mahtani, A G; Pollack, G H

    2012-01-01

    Solute-free zones, termed "exclusion zones" are routinely seen next to hydrophilic surfaces in aqueous solution. Here we report similar zones next to various metals. The largest, approximately 200 µm in width, was found adjacent to zinc. Other reactive metals, including aluminum, tin, lead, and tungsten exhibited distinct but smaller exclusion zones, while precious metals such as platinum and gold did not produce any. Electrical potential measurements showed positive potentials within the exclusion zones, while pH measurements revealed an abundance of OH(-) groups in the aqueous regions beyond the exclusion zones. A correspondence was found between exclusion-zone size and the respective metal's position within the galvanic series. The presence of these interfacial exclusion zones is unexpected, and may shed new light on electrochemical processes taking place at metal interfaces. PMID:23807904

  15. Transition-Metal Doped Ceria Microspheres with Nanoporous Structures for CO Oxidation

    NASA Astrophysics Data System (ADS)

    Zhou, Lin; Li, Xiaoxiao; Yao, Ze; Chen, Zhuwen; Hong, Mei; Zhu, Rongshu; Liang, Yongye; Zhao, Jing

    2016-03-01

    Catalytic oxidation of carbon monoxide (CO) is of great importance in many different fields of industry. Until now it still remains challenging to use non-noble metal based catalysts to oxidize CO at low temperature. Herein, we report a new class of nanoporous, uniform, and transition metal-doped cerium (IV) oxide (ceria, CeO2) microsphere for CO oxidation catalysis. The porous and uniform microsphere is generated by sacrificed polymer template. Transition-metals, like Cu, Co, Ni, Mn and Fe, were doped into CeO2 microspheres. The combination of hierarchical structure and metal doping afford superior catalytic activities of the doped ceria microspheres, which could pave a new way to advanced non-precious metal based catalysts for CO oxidation.

  16. Transition-Metal Doped Ceria Microspheres with Nanoporous Structures for CO Oxidation

    PubMed Central

    Zhou, Lin; Li, Xiaoxiao; Yao, Ze; Chen, Zhuwen; Hong, Mei; Zhu, Rongshu; Liang, Yongye; Zhao, Jing

    2016-01-01

    Catalytic oxidation of carbon monoxide (CO) is of great importance in many different fields of industry. Until now it still remains challenging to use non-noble metal based catalysts to oxidize CO at low temperature. Herein, we report a new class of nanoporous, uniform, and transition metal-doped cerium (IV) oxide (ceria, CeO2) microsphere for CO oxidation catalysis. The porous and uniform microsphere is generated by sacrificed polymer template. Transition-metals, like Cu, Co, Ni, Mn and Fe, were doped into CeO2 microspheres. The combination of hierarchical structure and metal doping afford superior catalytic activities of the doped ceria microspheres, which could pave a new way to advanced non-precious metal based catalysts for CO oxidation. PMID:27030159

  17. Astronomical Institute of Athens

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    The Astronomical Institute of Athens is the oldest research institute of modern Greece (it faces the Parthenon). The Astronomical Institute (AI) of the National Observatory of Athens (NOA) started its observational projects in 1847. The modern computer and research center are housed at the Penteli Astronomical Station with major projects and international collaborations focused on extragalactic ...

  18. Noble metal-free hydrogen evolution catalysts for water splitting.

    PubMed

    Zou, Xiaoxin; Zhang, Yu

    2015-08-01

    Sustainable hydrogen production is an essential prerequisite of a future hydrogen economy. Water electrolysis driven by renewable resource-derived electricity and direct solar-to-hydrogen conversion based on photochemical and photoelectrochemical water splitting are promising pathways for sustainable hydrogen production. All these techniques require, among many things, highly active noble metal-free hydrogen evolution catalysts to make the water splitting process more energy-efficient and economical. In this review, we highlight the recent research efforts toward the synthesis of noble metal-free electrocatalysts, especially at the nanoscale, and their catalytic properties for the hydrogen evolution reaction (HER). We review several important kinds of heterogeneous non-precious metal electrocatalysts, including metal sulfides, metal selenides, metal carbides, metal nitrides, metal phosphides, and heteroatom-doped nanocarbons. In the discussion, emphasis is given to the synthetic methods of these HER electrocatalysts, the strategies of performance improvement, and the structure/composition-catalytic activity relationship. We also summarize some important examples showing that non-Pt HER electrocatalysts could serve as efficient cocatalysts for promoting direct solar-to-hydrogen conversion in both photochemical and photoelectrochemical water splitting systems, when combined with suitable semiconductor photocatalysts. PMID:25886650

  19. Fabrication of crystals from single metal atoms

    PubMed Central

    Barry, Nicolas P. E.; Pitto-Barry, Anaïs; Sanchez, Ana M.; Dove, Andrew P.; Procter, Richard J.; Soldevila-Barreda, Joan J.; Kirby, Nigel; Hands-Portman, Ian; Smith, Corinne J.; O’Reilly, Rachel K.; Beanland, Richard; Sadler, Peter J.

    2014-01-01

    Metal nanocrystals offer new concepts for the design of nanodevices with a range of potential applications. Currently the formation of metal nanocrystals cannot be controlled at the level of individual atoms. Here we describe a new general method for the fabrication of multi-heteroatom-doped graphitic matrices decorated with very small, ångström-sized, three-dimensional (3D)-metal crystals of defined size. We irradiate boron-rich precious-metal-encapsulated self-spreading polymer micelles with electrons and produce, in real time, a doped graphitic support on which individual osmium atoms hop and migrate to form 3D-nanocrystals, as small as 15 Å in diameter, within 1 h. Crystal growth can be observed, quantified and controlled in real time. We also synthesize the first examples of mixed ruthenium–osmium 3D-nanocrystals. This technology not only allows the production of ångström-sized homo- and hetero-crystals, but also provides new experimental insight into the dynamics of nanocrystals and pathways for their assembly from single atoms. PMID:24861089

  20. Integration of ground-penetrating radar, ultrasonic tests and infrared thermography for the analysis of a precious medieval rose window

    NASA Astrophysics Data System (ADS)

    Nuzzo, L.; Calia, A.; Liberatore, D.; Masini, N.; Rizzo, E.

    2010-04-01

    The integration of high-resolution, non-invasive geophysical techniques (such as ground-penetrating radar or GPR) with emerging sensing techniques (acoustics, thermography) can complement limited destructive tests to provide a suitable methodology for a multi-scale assessment of the state of preservation, material and construction components of monuments. This paper presents the results of the application of GPR, infrared thermography (IRT) and ultrasonic tests to the 13th century rose window of Troia Cathedral (Apulia, Italy), affected by widespread decay and instability problems caused by the 1731 earthquake and reactivated by recent seismic activity. This integrated approach provided a wide amount of complementary information at different scales, ranging from the sub-centimetre size of the metallic joints between the various architectural elements, narrow fractures and thin mortar fillings, up to the sub-metre scale of the internal masonry structure of the circular ashlar curb linking the rose window to the façade, which was essential to understand the original building technique and to design an effective restoration strategy.

  1. Mapping Hispanic-Serving Institutions: A Typology of Institutional Diversity

    ERIC Educational Resources Information Center

    Núñez, Anne-Marie; Crisp, Gloria; Elizondo, Diane

    2016-01-01

    Hispanic-Serving Institutions (HSIs), institutions that enroll at least 25% Hispanic students, are institutionally diverse, including a much wider array of institutional types than other Minority-Serving Institutions (MSIs). Furthermore, they have distinctive institutional characteristics from those typically emphasized in institutional typologies…

  2. Metal aminoboranes

    DOEpatents

    Burrell, Anthony K.; Davis, Benjamin J.; Thorn, David L.; Gordon, John C.; Baker, R. Thomas; Semelsberger, Troy Allen; Tumas, William; Diyabalanage, Himashinie Vichalya Kaviraj; Shrestha, Roshan P.

    2010-05-11

    Metal aminoboranes of the formula M(NH.sub.2BH.sub.3).sub.n have been synthesized. Metal aminoboranes are hydrogen storage materials. Metal aminoboranes are also precursors for synthesizing other metal aminoboranes. Metal aminoboranes can be dehydrogenated to form hydrogen and a reaction product. The reaction product can react with hydrogen to form a hydrogen storage material. Metal aminoboranes can be included in a kit.

  3. Bio‐palladium: from metal recovery to catalytic applications

    PubMed Central

    De Corte, Simon; Hennebel, Tom; De Gusseme, Bart; Verstraete, Willy; Boon, Nico

    2012-01-01

    Summary While precious metals are available to a very limited extent, there is an increasing demand to use them as catalyst. This is also true for palladium (Pd) catalysts and their sustainable recycling and production are required. Since Pd catalysts exist nowadays mostly under the form of nanoparticles, these particles need to be produced in an environment‐friendly way. Biological synthesis of Pd nanoparticles (‘bio‐Pd’) is an innovative method for both metal recovery and nanocatalyst synthesis. This review will discuss the different bio‐Pd precipitating microorganisms, the applications of the catalyst (both for environmental purposes and in organic chemistry) and the state of the art of the reactors based on the bio‐Pd concept. In addition, some main challenges are discussed, which need to be overcome in order to create a sustainable nanocatalyst. Finally, some outlooks for bio‐Pd in environmental technology are presented. PMID:21554561

  4. Metal Resistance and Lithoautotrophy in the Extreme Thermoacidophile Metallosphaera sedula

    PubMed Central

    Maezato, Yukari; Johnson, Tyler; McCarthy, Samuel; Dana, Karl

    2012-01-01

    Archaea such as Metallosphaera sedula are thermophilic lithoautotrophs that occupy unusually acidic and metal-rich environments. These traits are thought to underlie their industrial importance for bioleaching of base and precious metals. In this study, a genetic approach was taken to investigate the specific relationship between metal resistance and lithoautotrophy during biotransformation of the primary copper ore, chalcopyrite (CuFeS2). In this study, a genetic system was developed for M. sedula to investigate parameters that limit bioleaching of chalcopyrite. The functional role of the M. sedula copRTA operon was demonstrated by cross-species complementation of a copper-sensitive Sulfolobus solfataricus copR mutant. Inactivation of the gene encoding the M. sedula copper efflux protein, copA, using targeted recombination compromised metal resistance and eliminated chalcopyrite bioleaching. In contrast, a spontaneous M. sedula mutant (CuR1) with elevated metal resistance transformed chalcopyrite at an accelerated rate without affecting chemoheterotrophic growth. Proteomic analysis of CuR1 identified pleiotropic changes, including altered abundance of transport proteins having AAA-ATPase motifs. Addition of the insoluble carbonate mineral witherite (BaCO3) further stimulated chalcopyrite lithotrophy, indicating that carbon was a limiting factor. Since both mineral types were actively colonized, enhanced metal leaching may arise from the cooperative exchange of energy and carbon between surface-adhered populations. Genetic approaches provide a new means of improving the efficiency of metal bioleaching by enhancing the mechanistic understanding of thermophilic lithoautotrophy. PMID:23065978

  5. UNEXPECTED PRESENCE OF SOLUTE-FREE ZONES AT METAL-WATER INTERFACES

    PubMed Central

    Chai, B.; Mahtani, A. G.; Pollack, G. H.

    2013-01-01

    Solute–free zones, termed “exclusion zones” are routinely seen next to hydrophilic surfaces in aqueous solution. Here we report similar zones next to various metals. The largest, approximately 200 µm in width, was found adjacent to zinc. Other reactive metals, including aluminum, tin, lead, and tungsten exhibited distinct but smaller exclusion zones, while precious metals such as platinum and gold did not produce any. Electrical potential measurements showed positive potentials within the exclusion zones, while pH measurements revealed an abundance of OH− groups in the aqueous regions beyond the exclusion zones. A correspondence was found between exclusion-zone size and the respective metal’s position within the galvanic series. The presence of these interfacial exclusion zones is unexpected, and may shed new light on electrochemical processes taking place at metal interfaces. PMID:23807904

  6. Astrophysical Institute, Potsdam

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    Built upon a tradition of almost 300 years, the Astrophysical Institute Potsdam (AIP) is in an historical sense the successor of one of the oldest astronomical observatories in Germany. It is the first institute in the world which incorporated the term `astrophysical' in its name, and is connected with distinguished scientists such as Karl Schwarzschild and Albert Einstein. The AIP constitutes on...

  7. Institutional Inbreeding Reexamined.

    ERIC Educational Resources Information Center

    Wyer, Jean C.; Conrad, Clifton F.

    1984-01-01

    Data from the 1977 Survey of the American Professoriate were used to examine the relationship among institutional origin, productivity, and institutional rewards. When an adjustment was made for time allocation, inbred faculty were found to be more productive but are paid significantly less than noninbred faculty. (Author/BW)

  8. Institutionalism "Old" and "New."

    ERIC Educational Resources Information Center

    Selznick, Philip

    1996-01-01

    Explores the new institutionalism's ethos and direction. Drawing a sharp line between old and new inhibits the contribution of institutional theory to major issues of bureaucracy and social policy. Problems of accountability and responsiveness, public and private bureaucracy, regulation and self-regulation, and management and governance will…

  9. Evaluating Residential Institutions.

    ERIC Educational Resources Information Center

    Millham, Spencer

    Drawing on the research experience of the Dartington Social Research Unit, this paper discusses methods and perspectives used in evaluating English residential institutions for children. Work of the Dartington Social Research Unit has involved evaluating aspects of a wide range of institutions, from elite boarding schools to children's homes and…

  10. Understanding Institutional Image.

    ERIC Educational Resources Information Center

    Terkla, Dawn Geronimo; Pagano, Marian F.

    1993-01-01

    The use of a semantic differential measure to investigate the institutional image of Tufts University (Massachusetts), both internal and external, is reported. The study focused on (1) differences between the current and desired image, and (2) differences among alumni, current student, and other constituencies' views of the institution.…

  11. Engagement and Institutional Advancement

    ERIC Educational Resources Information Center

    Weerts, David; Hudson, Elizabeth

    2009-01-01

    Research suggests that institutional commitment to community engagement can be understood by examining levels of student, faculty, and community involvement in engagement; organizational structure, rewards, and campus publications supporting engagement; and compatibility of an institution's mission with this work (Holland, 1997). Underlying all of…

  12. Revising the Institutional Mission.

    ERIC Educational Resources Information Center

    Dominick, Charles A.

    1990-01-01

    Revision of a college mission statement through a broadly participatory process can provide a new and sharpened sense of direction and priorities and a powerful mechanism for institutional change. Although institutional circumstances and processes may differ, the experience of Wittenberg University (Ohio) serves as an example of a model for…

  13. A new class of electrocatalysts for hydrogen production from water electrolysis: metal monolayers supported on low-cost transition metal carbides.

    PubMed

    Esposito, Daniel V; Hunt, Sean T; Kimmel, Yannick C; Chen, Jingguang G

    2012-02-15

    This work explores the opportunity to substantially reduce the cost of hydrogen evolution reaction (HER) catalysts by supporting monolayer (ML) amounts of precious metals on transition metal carbide substrates. The metal component includes platinum (Pt), palladium (Pd), and gold (Au); the low-cost carbide substrate includes tungsten carbides (WC and W(2)C) and molybdenum carbide (Mo(2)C). As a platform for these studies, single-phase carbide thin films with well-characterized surfaces have been synthesized, allowing for a direct comparison of the intrinsic HER activity of bare and Pt-modified carbide surfaces. It is found that WC and W(2)C are both excellent cathode support materials for ML Pt, exhibiting HER activities that are comparable to bulk Pt while displaying stable HER activity during chronopotentiometric HER measurements. The findings of excellent stability and HER activity of the ML Pt-WC and Pt-W(2)C surfaces may be explained by the similar bulk electronic properties of tungsten carbides to Pt, as is supported by density functional theory calculations. These results are further extended to other metal overlayers (Pd and Au) and supports (Mo(2)C), which demonstrate that the metal ML-supported transition metal carbide surfaces exhibit HER activity that is consistent with the well-known volcano relationship between activity and hydrogen binding energy. This work highlights the potential of using carbide materials to reduce the costs of hydrogen production from water electrolysis by serving as stable, low-cost supports for ML amounts of precious metals. PMID:22280370

  14. Metal recovery from high-grade WEEE: a life cycle assessment.

    PubMed

    Bigum, Marianne; Brogaard, Line; Christensen, Thomas H

    2012-03-15

    Based on available data in the literature the recovery of aluminium, copper, gold, iron, nickel, palladium and silver from high-grade WEEE was modeled by LCA. The pre-treatment of WEEE included manual sorting, shredding, magnetic sorting, Eddy-current sorting, air classification and optical sorting. The modeled metallurgical treatment facility included a Kaldo plant, a converter aisle, an anode refinery and a precious metal refinery. The metallurgic treatment showed significant environmental savings when credited the environmental load from avoided production of the same amount of metals by mining and refining of ore. The resource recovery per tonne of high-grade WEEE ranged from 2g of palladium to 386kg of iron. Quantified in terms of person-equivalents the recovery of palladium, gold, silver, nickel and copper constituted the major environmental benefit of the recovery of metals from WEEE. These benefits are most likely underestimated in the model, since we did not find adequate data to include all the burdens from mining and refining of ore; burdens that are avoided when metals are recovered from WEEE. The processes connected to the pre-treatment of WEEE were found to have little environmental effect compared to the metallurgical treatment. However only 12-26% of silver, gold and palladium are recovered during pre-treatment, which suggest that the reduction of the apparent losses of precious metals as palladium, gold and silver during pre-treatment of WEEE is of environmental importance. Our results support in a quantitative manner that metal recovery from WEEE should be quantified with respect to the individual metals recovered and not as a bulk metal recovery rate. PMID:22115841

  15. Fate of metals contained in waste electrical and electronic equipment in a municipal waste treatment process.

    PubMed

    Oguchi, Masahiro; Sakanakura, Hirofumi; Terazono, Atsushi; Takigami, Hidetaka

    2012-01-01

    In Japan, waste electrical and electronic equipment (WEEE) that is not covered by the recycling laws are treated as municipal solid waste. A part of common metals are recovered during the treatment; however, other metals are rarely recovered and their destinations are not clear. This study investigated the distribution ratios and substance flows of 55 metals contained in WEEE during municipal waste treatment using shredding and separation techniques at a Japanese municipal waste treatment plant. The results revealed that more than half of Cu and most of Al contained in WEEE end up in landfills or dissipate under the current municipal waste treatment system. Among the other metals contained in WEEE, at least 70% of the mass was distributed to the small-grain fraction through the shredding and separation and is to be landfilled. Most kinds of metals were concentrated several fold in the small-grain fraction through the process and therefore the small-grain fraction may be a next target for recovery of metals in terms of both metal content and amount. Separate collection and pre-sorting of small digital products can work as effective way for reducing precious metals and less common metals to be landfilled to some extent; however, much of the total masses of those metals would still end up in landfills and it is also important to consider how to recover and utilize metals contained in other WEEE such as audio/video equipment. PMID:21963338

  16. Development and application of biotechnologies in the metal mining industry.

    PubMed

    Johnson, D Barrie

    2013-11-01

    Metal mining faces a number of significant economic and environmental challenges in the twenty-first century for which established and emerging biotechnologies may, at least in part, provide the answers. Bioprocessing of mineral ores and concentrates is already used in variously engineered formats to extract base (e.g., copper, cobalt, and nickel) and precious (gold and silver) metals in mines throughout the world, though it remains a niche technology. However, current projections of an increasing future need to use low-grade primary metal ores, to reprocess mine wastes, and to develop in situ leaching technologies to extract metals from deep-buried ore bodies, all of which are economically more amenable to bioprocessing than conventional approaches (e.g., pyrometallurgy), would suggest that biomining will become more extensively utilized in the future. Recent research has also shown that bioleaching could be used to process a far wider range of metal ores (e.g., oxidized ores) than has previously been the case. Biotechnologies are also being developed to control mine-related pollution, including securing mine wastes (rocks and tailings) by using "ecological engineering" approaches, and also to remediate and recover metals from waste waters, such as acid mine drainage. This article reviews the current status of biotechnologies within the mining sector and considers how these may be developed and applied in future years. PMID:23329131

  17. Metal inks

    DOEpatents

    Ginley, David S; Curtis, Calvin J; Miedaner, Alex; van Hest, Marinus Franciscus Antonius Maria; Kaydanova, Tatiana

    2014-02-04

    Self-reducing metal inks and systems and methods for producing and using the same are disclosed. In an exemplary embodiment, a method may comprise selecting metal-organic (MO) precursor, selecting a reducing agent, and dissolving the MO precursor and the reducing agent in an organic solvent to produce a metal ink that remains in a liquid phase at room temperature. Metal inks, including self-reducing and fire-through metal inks, are also disclosed, as are various applications of the metal inks.

  18. A preliminary categorization of end-of-life electrical and electronic equipment as secondary metal resources

    SciTech Connect

    Oguchi, Masahiro; Murakami, Shinsuke; Sakanakura, Hirofumi; Kida, Akiko; Kameya, Takashi

    2011-09-15

    Highlights: > End-of-life electrical and electronic equipment (EEE) as secondary metal resources. > The content and the total amount of metals in specific equipment are both important. > We categorized 21 EEE types from contents and total amounts of various metals. > Important equipment types as secondary resources were listed for each metal kind. > Collectability and possible collection systems of various EEE types were discussed. - Abstract: End-of-life electrical and electronic equipment (EEE) has recently received attention as a secondary source of metals. This study examined characteristics of end-of-life EEE as secondary metal resources to consider efficient collection and metal recovery systems according to the specific metals and types of EEE. We constructed an analogy between natural resource development and metal recovery from end-of-life EEE and found that metal content and total annual amount of metal contained in each type of end-of-life EEE should be considered in secondary resource development, as well as the collectability of the end-of-life products. We then categorized 21 EEE types into five groups and discussed their potential as secondary metal resources. Refrigerators, washing machines, air conditioners, and CRT TVs were evaluated as the most important sources of common metals, and personal computers, mobile phones, and video games were evaluated as the most important sources of precious metals. Several types of small digital equipment were also identified as important sources of precious metals; however, mid-size information and communication technology (ICT) equipment (e.g., printers and fax machines) and audio/video equipment were shown to be more important as a source of a variety of less common metals. The physical collectability of each type of EEE was roughly characterized by unit size and number of end-of-life products generated annually. Current collection systems in Japan were examined and potentially appropriate collection methods

  19. Minority Innovation Challenges Institute

    NASA Video Gallery

    Do you want to learn more about how to compete in NASA’s technical challenges for both prestige and significant cash prizes? NASA’s Minority Innovation Challenges Institute trains and mentors mino...

  20. Institutionally based videoconferencing.

    PubMed

    Caudill, Robert Lee; Sager, Zachary

    2015-01-01

    The delivery of psychiatric care via video-teleconferencing (VTC) technology is thought to have reached a tipping point. As a medical speciality with relatively few material or technical requirements for service delivery, psychiatry has been one of the earliest to embrace the possibility of providing evaluations and treatment at a distance. Such technical infrastructure as is necessary can often be found in the institutions already in existence. It was natural therefore that institutionally based telepsychiatry would lay the foundation for the development of the field. In this article we review the history and development of institutional VTC in a wide variety of clinically supervised settings such as hospitals, outpatient clinics, and forensic settings. We cite evidence supporting institutionally sponsored use and expand on key takeaways for the development and expansion of videoconferencing in these settings. We also speculate on the future direction and development of psychiatric care provided by these arrangements. PMID:26507786

  1. National Institute on Aging

    MedlinePlus

    ... Join Our Mailing List Email The Leader in Aging Research NIA, one of the 27 Institutes and ... broad scientific effort to understand the nature of aging and to extend the healthy, active years of ...

  2. Critical Materials Institute

    SciTech Connect

    Alex King

    2013-01-09

    Ames Laboratory Director Alex King talks about the goals of the Critical Materials Institute in diversifying the supply of critical materials, developing substitute materials, developing tools and techniques for recycling critical materials, and forecasting materials needs to avoid future shortages.

  3. Critical Materials Institute

    ScienceCinema

    Alex King

    2013-06-05

    Ames Laboratory Director Alex King talks about the goals of the Critical Materials Institute in diversifying the supply of critical materials, developing substitute materials, developing tools and techniques for recycling critical materials, and forecasting materials needs to avoid future shortages.

  4. Institute for Science Education

    ERIC Educational Resources Information Center

    Schaefer, G.

    1974-01-01

    The functions of the Institute for Science Education (IPN) at Kiel, West Germany, are described. The main activities of the IPN focus on development of curricula for science education and investigation of special problems arising in science teaching. (PEB)

  5. Breaking down institutional barriers: Undergraduate institutions

    SciTech Connect

    Morrison, C.

    1995-12-31

    This paper assesses the knowledge base on the undergraduate years, and the critical transition to graduate school or the workplace. The paper addresses the overarching issues associated with the institutional climate of undergraduate colleges and the transition on to the next step. What are the particular dynamics of retaining students in SM&E? How do these differ for various ethnic groups and by discipline? What has been the impact on minority students of curriculum reform and attempts to improve the quality of undergraduate instruction in the sciences and mathematics (especially among the gatekeeper courses)? Do present curriculum reforms and teaching practices reflect what is known about different learning styles of students from different ethnic backgrounds? What do we know about the attitudes and practices of college faculty in mentoring minority students in science and math courses? Has mentoring been a factor for change in campus climate? What do we know about higher education interventions, and why have these programs been more successful in engineering than in science? Can interventions change negative campus climates, or become a precipitating factor institutional change?

  6. Great Lakes Energy Institute

    SciTech Connect

    Alexander, J. Iwan

    2012-11-18

    The vision of the Great Lakes Energy Institute is to enable the transition to advanced, sustainable energy generation, storage, distribution and utilization through coordinated research, development, and education. The Institute will place emphasis on translating leading edge research into next generation energy technology. The Institute’s research thrusts focus on coordinated research in decentralized power generation devices (e.g. fuel cells, wind turbines, solar photovoltaic devices), management of electrical power transmission and distribution, energy storage, and energy efficiency.

  7. National Cancer Institute Perspectives

    SciTech Connect

    Wong, Rosemary S.L. . E-mail: rw26f@nih.gov; Brechbiel, Martin W.

    2006-10-01

    The National Cancer Institute (NCI) Perspectives this year presented information on the systemic targeted radionuclide therapy (STaRT) research projects: (1) being investigated at the NCI's Intramural Center for Cancer Research; (2) funded by NCI's Radiation Research Program and other extramural programs; and (3) the appropriate National Institutes of Health/NCI funding mechanisms applicable to researchers for obtaining funds for STaRT projects.

  8. Metallization failures

    NASA Technical Reports Server (NTRS)

    Beatty, R.

    1971-01-01

    Metallization-related failure mechanisms were shown to be a major cause of integrated circuit failures under accelerated stress conditions, as well as in actual use under field operation. The integrated circuit industry is aware of the problem and is attempting to solve it in one of two ways: (1) better understanding of the aluminum system, which is the most widely used metallization material for silicon integrated circuits both as a single level and multilevel metallization, or (2) evaluating alternative metal systems. Aluminum metallization offers many advantages, but also has limitations particularly at elevated temperatures and high current densities. As an alternative, multilayer systems of the general form, silicon device-metal-inorganic insulator-metal, are being considered to produce large scale integrated arrays. The merits and restrictions of metallization systems in current usage and systems under development are defined.

  9. METAL PHTHALOCYANINES

    DOEpatents

    Frigerio, N.A.

    1962-03-27

    A process is given for preparing heavy metal phthalocyanines, sulfonated or not. The process comprises mixing an inorganic metal salt with dimethyl formamide or methyl sulfoxide; separating the metal complex formed from the solution; mixing the complex with an equimolar amount of sodium, potassium, lithium, magnesium, or beryllium sulfonated or unsulfonated phthalocyanine whereby heavy-metal phthalocyanine crystals are formed; and separating the crystals from the solution. Uranyl, thorium, lead, hafnium, and lanthanide rare earth phthalocyanines can be produced by the process. (AEC)

  10. Silicone metalization

    DOEpatents

    Maghribi, Mariam N.; Krulevitch, Peter; Hamilton, Julie

    2006-12-05

    A system for providing metal features on silicone comprising providing a silicone layer on a matrix and providing a metal layer on the silicone layer. An electronic apparatus can be produced by the system. The electronic apparatus comprises a silicone body and metal features on the silicone body that provide an electronic device.

  11. Silicone metalization

    DOEpatents

    Maghribi, Mariam N.; Krulevitch, Peter; Hamilton, Julie

    2008-12-09

    A system for providing metal features on silicone comprising providing a silicone layer on a matrix and providing a metal layer on the silicone layer. An electronic apparatus can be produced by the system. The electronic apparatus comprises a silicone body and metal features on the silicone body that provide an electronic device.

  12. Water: Too Precious to Waste.

    ERIC Educational Resources Information Center

    National Geographic World, 1983

    1983-01-01

    Provides background information on many topics related to water. These include the water cycle, groundwater, fresh water, chemical wastes, water purification, river pollution, acid rain, and water conservation. Information is presented at an elementary level. (JM)

  13. Renewable and metal-free carbon nanofibre catalysts for carbon dioxide reduction

    NASA Astrophysics Data System (ADS)

    Kumar, Bijandra; Asadi, Mohammad; Pisasale, Davide; Sinha-Ray, Suman; Rosen, Brian A.; Haasch, Richard; Abiade, Jeremiah; Yarin, Alexander L.; Salehi-Khojin, Amin

    2013-12-01

    The development of an efficient catalyst system for the electrochemical reduction of carbon dioxide into energy-rich products is a major research topic. Here we report the catalytic ability of polyacrylonitrile-based heteroatomic carbon nanofibres for carbon dioxide reduction into carbon monoxide, via a metal-free, renewable and cost-effective route. The carbon nanofibre catalyst exhibits negligible overpotential (0.17 V) for carbon dioxide reduction and more than an order of magnitude higher current density compared with the silver catalyst under similar experimental conditions. The carbon dioxide reduction ability of carbon nanofibres is attributed to the reduced carbons rather than to electronegative nitrogen atoms. The superior performance is credited to the nanofibrillar structure and high binding energy of key intermediates to the carbon nanofibre surfaces. The finding may lead to a new generation of metal-free and non-precious catalysts with much greater efficiency than the existing noble metal catalysts.

  14. Institutional Policy and Its Abuses

    ERIC Educational Resources Information Center

    Bogue, E. G.; Riggs, R. O.

    1974-01-01

    Reviews the role of institutional policy, cites frequent abuses of institutional policy, and delineates several principles of policy management (development, communication, execution and evaluation). (Author/PG)

  15. Honors and Institutional Transformation

    ERIC Educational Resources Information Center

    Ransdell, Gary A.

    2015-01-01

    Honors colleges and programs often evolve in response to a mandate from boards of regents or trustees. Such mandates can lead to new or accelerated change within the institution, change that in many cases is linked to and represented by honors. Such has been the case at Western Kentucky University (WKU), where the honors program has played a key…

  16. An Institute for Inquiry

    ERIC Educational Resources Information Center

    Kelly, Janet; Weis, R. Stephen

    2005-01-01

    This article discusses professional development that offers practical tips for elementary teachers to implement in their classrooms right away. The programs at the Institute of Math, Science, and Technology Education at Texas Christian University at Fort Worth, Texas, offer a professional development model. In this successful collaborative, formed…

  17. Instituting the Greater Good

    ERIC Educational Resources Information Center

    Matthews, Frank

    2011-01-01

    Teachers, higher education administrators and financial planners are well acquainted with the work of TIAA-CREF. The insurance and investment company has been a central player in teacher retirement and financial planning for nearly a century. Twelve years ago, the organization spawned the TIAA-CREF Institute, a research-focused arm that brings…

  18. Managing Institutional Image.

    ERIC Educational Resources Information Center

    Melchiori, Gerlinda S.

    1990-01-01

    A managerial process for enhancing the image and public reputation of a higher education institution is outlined. It consists of five stages: market research; data analysis and market positioning; communication of results and recommendations to the administration; development of a global image program; and impact evaluation. (MSE)

  19. Confronting Institutional Racism.

    ERIC Educational Resources Information Center

    Keleher, Terry; Johnson, Tammy

    2001-01-01

    The best way to measure institutional racism is to examine effects (statistical outcomes), not intentions. Administrators can actively address racial inequality, collect realistic data, combine equity and quality considerations in all policies, support accountability while resisting high-stakes tests, involve the whole community, and avoid silver…

  20. Institute Born of Gratitude.

    ERIC Educational Resources Information Center

    McLellan, Vin

    1980-01-01

    The Wang Institute of Graduate Studies plans to offer a master's degree in software engineering. The development of an academic program to produce superior, technically qualified managers for the computer industry's software production is discussed. (Journal availability: Datamation, 666 Fifth Ave., New York, NY 10103.) (MLW)

  1. A Contested Institutional Culture

    ERIC Educational Resources Information Center

    Morin, Stephanie A.

    2010-01-01

    The College of William and Mary (Williamsburg, Virginia) found itself at a crossroads in 2005. Their long-popular president Timothy J. Sullivan was retiring after 13 years at the helm of the world's second oldest institution of higher education (Petkofsky, 2004). Long known as a bastion of conservatism, William and Mary could now change their…

  2. SOFTWARE ENGINEERING INSTITUTE (SEI)

    EPA Science Inventory

    The Software Engineering Institute (SEI) is a federally funded research and development center established in 1984 by the U.S. Department of Defense and operated by Carnegie Mellon University. SEI has a broad charter to provide leadership in the practice of software engineering t...

  3. Institutional Effectiveness Indicators.

    ERIC Educational Resources Information Center

    Parker, Lynn S.; And Others

    Prepared for discussion at a retreat of the board of trustees of Florida Community College at Jacksonville (FCCJ), this packet of materials identifies 31 indicators of institutional performance and assesses FCCJ in terms of those indicators for which data were available. First, the packet presents a flow chart which illustrates the model used by…

  4. Implementing Sustainable Institutional Practices

    ERIC Educational Resources Information Center

    Shepard, Joseph; Johnson, Lewis

    2009-01-01

    Recent research has found that few institutions of higher education implemented the necessary strategies to make their campuses sustainable (Thompson and Green 2005). Ironically, universities are the segment of society with the most access to the intellectual capital needed to provide sound sustainable practices and measurements. Having top…

  5. Taylor Business Institute, Report.

    ERIC Educational Resources Information Center

    Barber, Jerry

    The Office of the State Comptroller in New York audited the records and procedures used in administering the Tuition Assistance Program (TAP) at Taylor Business Institute (Taylor) for the academic years 1995-96 through 1997-98. Taylor, located in Manhattan, offers both degree programs and diploma programs in Accounting, Business Management,…

  6. Planning for Institutional Effectiveness.

    ERIC Educational Resources Information Center

    Wright, Frank W., Comp.; Garthwaite, Elloyse M., Comp.

    Drawing from the experiences of Delgado Community College (DCC) in Louisiana, this manual offers guidance on choosing and implementing an institutional planning system. Section 1 offers introductory comments on planning, educators' reluctance to embrace the management systems of the private sector, and the growing recognition of the importance of…

  7. Institutional Research Bulletin, 1993.

    ERIC Educational Resources Information Center

    Abou-Sayf, Frank, Ed.

    1993-01-01

    The "Institutional Research Bulletin" is a collection of research summaries relating to Kapi'olani Community College (KCC) in Hawaii. Highlights from the 1993 volume (September-December) include: (1) the number of students in art classes and programs increased from 1988-1992; (2) the results of a survey about how health students find out about KCC…

  8. Personnel Management Institutes 1974.

    ERIC Educational Resources Information Center

    Hinman, Stanley B., Jr.

    This report is a compilation of presentations made at the Personnel Management Institutes held by the New York State School Boards Association in the fall of 1974. Included are the following six presentations: "New Laws Affecting School Boards and School Administration," by Bernard T. McGivern; "How to Prepare for Tenure Hearings, PERB Hearings,…

  9. Leadership in Educational Institutions

    ERIC Educational Resources Information Center

    Sunko, Esmeralda

    2012-01-01

    Many questions concerning quality of functioning and effectiveness are connected with the management of education as a professional field in educational organizations. The role of educational leadership in an educational organization raises many questions related to legislative regulations of activities, issues of institutional placement,…

  10. Defense Language Institute.

    ERIC Educational Resources Information Center

    Defense Language Inst., Washington, DC.

    Discussed in this Defense Language Institute (DLI) brochure are its intensive language programs' history, and its four schools, which are located in Monterey, California, Washington, D.C., Lackland Air Force Base, and Fort Bliss, Texas. Proficiency levels determined by the DLI and utilization of the audiolingual method are also described.…

  11. One Institution: Six Alternatives.

    ERIC Educational Resources Information Center

    Adkins, Winthrop R.; And Others

    1971-01-01

    This expanded issue of the Research Review examines six alternatives to current patterns in the community college. In the first article, the authors offer guidelines for formulating institution-building capabilities, developing curricula, and designing a Personal Development program according to a Life Skills Education model. The second paper…

  12. Asian Institute of Technology.

    ERIC Educational Resources Information Center

    Office of Naval Research, London (England).

    The Asian Institute of Technology is a notable success for that part of the world where success is not too common. It is an excellent example of not only the initiative and organization of a technical university, but also of the success of a foreign aid program. This report gives details of this organization and accomplishments. (Author)

  13. Summer Youth Forestry Institute

    ERIC Educational Resources Information Center

    Roesch, Gabrielle E.; Neuffer, Tamara; Zobrist, Kevin

    2013-01-01

    The Summer Youth Forestry Institute (SYFI) was developed to inspire youth through experiential learning opportunities and early work experience in the field of natural resources. Declining enrollments in forestry and other natural resource careers has made it necessary to actively engage youth and provide them with exposure to careers in these…

  14. The branding of institutions.

    PubMed

    Stephenson, S

    1991-02-20

    Institutional operations capitalizing on national foodservice brands have seen sales increase as much as 40%, operators say. But what if operators choose to stay independent and develop their own brands? Our feature presents both business strategies and the concepts that are winning customers. PMID:10109711

  15. Effect of metal conditioner on bonding of porcelain to cobalt-chromium alloy

    PubMed Central

    Kajihara, Yutaro; Takenouchi, Yoshihisa; Tanaka, Takuo; Suzuki, Shiro; Minami, Hiroyuki

    2016-01-01

    PURPOSE The purpose of this study was to evaluate the efficacy of two different metal conditioners for non-precious metal alloys for the bonding of porcelain to a cobalt-chromium (Co-Cr) alloy. MATERIALS AND METHODS Disk-shaped specimens (2.5×10.0 mm) were cast with Co-Cr alloy and used as adherend materials. The bonding surfaces were polished with a 600-grid silicon carbide paper and airborne-particle abraded using 110 µm alumina particles. Bonding specimens were fabricated by applying and firing either of the metal conditioners on the airborne-particle abraded surface, followed by firing porcelain into 5 mm in diameter and 3 mm in height. Specimens without metal conditioner were also fabricated. Shear bond strength for each group (n=8) were measured and compared (α=.05). Sectional view of bonding interface was observed by SEM. EDS analysis was performed to determine the chemical elements of metal conditioners and to determine the failure modes after shear test. RESULTS There were significant differences among three groups, and two metal conditioner-applied groups showed significantly higher values compared to the non-metal conditioner group. The SEM observation of the sectional view at bonding interface revealed loose contact at porcelain-alloy surface for non-metal conditioner group, however, close contact at both alloy-metal conditioner and metal conditioner-porcelain interfaces for both metal conditioner-applied groups. All the specimens showed mixed failures. EDS analysis showed that one metal conditioner was Si-based material, and another was Ti-based material. Si-based metal conditioner showed higher bond strengths compared to the Ti-based metal conditioner, but exhibited more porous failure surface failure. CONCLUSION Based on the results of this study, it can be stated that the application of metal conditioner is recommended for the bonding of porcelain to cobalt-chromium alloys. PMID:26949481

  16. Oprelvekin. Genetics Institute.

    PubMed

    Sitaraman, S V; Gewirtz, A T

    2001-10-01

    Genetics Institute has developed and launched oprelvekin (rhIL-11; Neumega), a recombinant form of human IL-11. In November 1997, the FDA cleared oprelvekin for the prevention of severe thrombocytopenia and the reduction of the need for platelet transfusions following myelosuppressive chemotherapy in susceptible patients with non-myeloid malignancies 12703021. The product was launched at the end of 1997 [312556]. By December 1999, phase III trials for Crohn's disease (CD) were underway [363007]. Genetics Institute had commenced a 150-patient phase II trial for mild-to-moderate CD and mucositis and the company planned to file regulatory procedures for the indication of CD in 1999 [271210]. An oral formulation for this indication has been developed. Oprelvekin is also undergoing phase I clinical trials for colitis [396157], phase II clinical trials for rheumatoid arthritis [413835] and clinical trials for psoriasis [299644]. In March 1997, Wyeth-Ayerst became the licensee for Europe, Africa, Latin America and Asia (with the exception of Japan). Genetics Institute holds marketing rights for North America [239273]. In Japan, oprelvekin is being developed by Genetics Institute and Yamanouchi; phase III trials have commenced [295049] and were ongoing in May 2001 [411763]. In April 1996, analysts at Yamaichi estimated launch in 2001 and maximum annual sales of over yen 10 billion [215896]. In January 1998, Morgan Stanley Dean Witter predicted Yamanouchi's share of sales to be yen 1 billion in 2001, rising to yen 2 billion in 2002 [315458]. Sales of oprelvekin were US $34 million for Genetics institute in fiscal 2000 while, in July 2001, Credit Suisse First Boston estimated that this figure will be US $30 million and US $34 million in 2001 and 2002, respectively [416883]. PMID:11890354

  17. Japanese research and development on metallic biomedical, dental, and healthcare materials

    NASA Astrophysics Data System (ADS)

    Niinomi, Mitsuo; Hanawa, Takao; Narushima, Takayuki

    2005-04-01

    There is considerable demand for metallic materials for use in medical and dental devices. Metals and alloys are widely used as biomedical materials and are indispensable in the medical field. In dentistry, metal is used for restorations, orthodontic wires, and dental implants. This article describes R&D on metallic biomaterials primarily conducted by the members of the Japan Institute of Metals.

  18. Generation of copper rich metallic phases from waste printed circuit boards

    SciTech Connect

    Cayumil, R.; Khanna, R.; Ikram-Ul-Haq, M.; Rajarao, R.; Hill, A.; Sahajwalla, V.

    2014-10-15

    Highlights: • Recycling and material recovery from waste printed circuit boards is very complex. • Thermoset polymers, ceramics and metals are present simultaneously in waste PCBs. • Heat treatment of PCBs was carried out at 1150 °C under inert conditions. • Various metallic phases could be segregated out as copper based metallic droplets. • Carbon and ceramics residues can be further recycled in a range of applications. - Abstract: The rapid consumption and obsolescence of electronics have resulted in e-waste being one of the fastest growing waste streams worldwide. Printed circuit boards (PCBs) are among the most complex e-waste, containing significant quantities of hazardous and toxic materials leading to high levels of pollution if landfilled or processed inappropriately. However, PCBs are also an important resource of metals including copper, tin, lead and precious metals; their recycling is appealing especially as the concentration of these metals in PCBs is considerably higher than in their ores. This article is focused on a novel approach to recover copper rich phases from waste PCBs. Crushed PCBs were heat treated at 1150 °C under argon gas flowing at 1 L/min into a horizontal tube furnace. Samples were placed into an alumina crucible and positioned in the cold zone of the furnace for 5 min to avoid thermal shock, and then pushed into the hot zone, with specimens exposed to high temperatures for 10 and 20 min. After treatment, residues were pulled back to the cold zone and kept there for 5 min to avoid thermal cracking and re-oxidation. This process resulted in the generation of a metallic phase in the form of droplets and a carbonaceous residue. The metallic phase was formed of copper-rich red droplets and tin-rich white droplets along with the presence of several precious metals. The carbonaceous residue was found to consist of slag and ∼30% carbon. The process conditions led to the segregation of hazardous lead and tin clusters in the

  19. Dental devices; dental noble metal alloys and dental base metal alloys; designation of special controls. Final rule.

    PubMed

    2004-08-23

    The Food and Drug Administration is amending the identification and classification regulations of gold-based alloys and precious metal alloys for clinical use and base alloys devices in order to designate a special control for these devices. FDA is also exempting these devices from premarket notification requirements. The agency is taking this action on its own initiative. This action is being taken under the Federal Food, Drug, and Cosmetic Act (the act), as amended by the Safe Medical Devices Act of 1990 (SMDA), and the Food and Drug Administration Modernization Act of 1997 (FDAMA). Elsewhere in this issue of the Federal Register, FDA is announcing the availability of the draft guidance documents that would serve as special controls for these devices. PMID:15329980

  20. Electrocatalytic Hydrogenation of Oxygenates using Earth-Abundant Transition-Metal Nanoparticles under Mild Conditions.

    PubMed

    Carroll, Kyler J; Burger, Thomas; Langenegger, Lukas; Chavez, Steven; Hunt, Sean T; Román-Leshkov, Yuriy; Brushett, Fikile R

    2016-08-01

    Electrocatalytic hydrogenation (ECH) is a sustainable pathway for the synthesis of value-added organic compounds, provided affordable catalysts with high activity, selectivity and durability are developed. Here, we synthesize Cu/C, Ni/C, and CuNi/C nanoparticles and compare their performance to Pt/C, Ru/C, PtRu/C for the ECH of hydroxyacetone, a bio-derived feedstock surrogate containing a carbonyl and a hydroxyl functional group. The non-precious metal electrocatalysts show promising conversion-time behavior, product selectivities, and Faradaic efficiencies. Ni/C forms propylene glycol with a selectivity of 89 % (at 80 % conversion), while Cu/C catalyzes ECH (52 % selectivity) and hydrodeoxygenation (HDO, 48 % selectivity, accounting for evaporation). CuNi/C shows increased turnover frequencies but reduced ECH selectivity (80 % at 80 % conversion) as compared to the Ni/C catalyst. Importantly, stability studies show that the non-precious metal catalysts do not leach at operating conditions. PMID:27337680

  1. Supported Molten Metal Membranes for Hydrogen Separation

    SciTech Connect

    Datta, Ravindra; Ma, Yi Hua; Yen, Pei-Shan; Deveau, Nicholas; Fishtik, Ilie; Mardilovich, Ivan

    2013-09-30

    We describe here our results on the feasibility of a novel dense metal membrane for hydrogen separation: Supported Molten Metal Membrane, or SMMM.1 The goal in this work was to develop these new membranes based on supporting thin films of low-melting, non- precious group metals, e.g., tin (Sn), indium (In), gallium (Ga), or their alloys, to provide a flux and selectivity of hydrogen that rivals the conventional but substantially more expensive palladium (Pd) or Pd alloy membranes, which are susceptible to poisoning by the many species in the coal-derived syngas, and further possess inadequate stability and limited operating temperature range. The novelty of the technology presented numerous challenges during the course of this project, however, mainly in the selection of appropriate supports, and in the fabrication of a stable membrane. While the wetting instability of the SMMM remains an issue, we did develop an adequate understanding of the interaction between molten metal films with porous supports that we were able to find appropriate supports. Thus, our preliminary results indicate that the Ga/SiC SMMM at 550 ºC has a permeance that is an order of magnitude higher than that of Pd, and exceeds the 2015 DOE target. To make practical SMM membranes, however, further improving the stability of the molten metal membrane is the next goal. For this, it is important to better understand the change in molten metal surface tension and contact angle as a function of temperature and gas-phase composition. A thermodynamic theory was, thus, developed, that is not only able to explain this change in the liquid-gas surface tension, but also the change in the solid-liquid surface tension as well as the contact angle. This fundamental understanding has allowed us to determine design characteristics to maintain stability in the face of changing gas composition. These designs are being developed. For further progress, it is also important to understand the nature of solution and

  2. Possible evidence for metal accretion onto the surfaces of metal-poor main-sequence stars

    SciTech Connect

    Hattori, Kohei; Yoshii, Yuzuru; Beers, Timothy C.; Carollo, Daniela; Lee, Young Sun

    2014-04-01

    The entire evolution of the Milky Way, including its mass-assembly and star-formation history, is imprinted onto the chemo-dynamical distribution function of its member stars, f(x, v, [X/H]), in the multi-dimensional phase space spanned by position, velocity, and elemental abundance ratios. In particular, the chemo-dynamical distribution functions for low-mass stars (e.g., G- or K-type dwarfs) are precious tracers of the earliest stages of the Milky Way's formation, since their main-sequence lifetimes approach or exceed the age of the universe. A basic tenet of essentially all previous analyses is that the stellar metallicity, usually parameterized as [Fe/H], is conserved over time for main-sequence stars (at least those that have not been polluted due to mass transfer from binary companions). If this holds true, any correlations between metallicity and kinematics for long-lived main-sequence stars of different masses, effective temperatures, or spectral types must strictly be the same, since they reflect the same mass-assembly and star-formation histories. By analyzing a sample of nearby metal-poor halo and thick-disk stars on the main sequence, taken from Data Release 8 of the Sloan Digital Sky Survey, we find that the median metallicity of G-type dwarfs is systematically higher (by about 0.2 dex) than that of K-type dwarfs having the same median rotational velocity about the Galactic center. If it can be confirmed, this finding may invalidate the long-accepted assumption that the atmospheric metallicities of long-lived stars are conserved over time.

  3. National Space Biomedical Research Institute

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This report outlines the National Space Biomedical Research Institute's (NSBRI) activities during FY 2004, the Institute's seventh year. It is prepared in accordance with Cooperative Agreement NCC 9-58 between NASA's Lyndon B. Johnson Space Center (JSC) and the Institute's lead institution, Baylor College of Medicine.

  4. Are Schools and Colleges Institutions?

    ERIC Educational Resources Information Center

    Glatter, Ron

    2015-01-01

    This paper asks whether schools and colleges should be regarded as institutions as well as organizations, and if so what are the implications. Different conceptions of "institution" are examined including an attempt to distinguish "institution" from "organization". It is suggested that institutions are committed to a…

  5. The Functions of Institutional Research.

    ERIC Educational Resources Information Center

    Saupe, Joe L.

    The nature and purpose of institutional research (IR), forms of research, and the function of IR in the organizational structures of colleges and universities are examined. Institutional research is defined as research conducted within a higher education institution to provide information that supports institutional planning, policy formulation,…

  6. [Symbolizm of medical institutions].

    PubMed

    Dworzański, Wojciech; Dworzańska, Anna; Niezabitowska, Ewa; Stolarek, Małgorzata; Opielak, Grzegorz; Madej, Barbara; Burdan, Franciszek

    2012-01-01

    Marketing in health service has become an indispensable tool for creating and maintaining a positive image of medical institutions which to a great extent determines their success on the market. This process entails not only providing professional, reliable and up-to-date patient care but also establishing good reputation among those who already use it and its potential customers. It should be recognizable also for deliverers, investors, competitors, media and particularly for society and local authorities. The key to success is professionalism of personnel and their identification with the mission of the institution and the direction of changes being implemented there. For a complete success and recognition is essential health care facilities, which affects virtually matched the name and symbol, and communication of people responsible for contact with the media. PMID:22400177

  7. Institutions and poverty.

    PubMed

    Tebaldi, Edinaldo; Mohan, Ramesh

    2010-01-01

    This study utilises eight alternative measures of institutions and the instrumental variable method to examine the impacts of institutions on poverty. The estimates show that an economy with a robust system to control corruption, an effective government, and a stable political system will create the conditions to promote economic growth, minimise income distribution conflicts, and reduce poverty. Corruption, ineffective governments, and political instability will not only hurt income levels through market inefficiencies, but also escalate poverty incidence via increased income inequality. The results also imply that the quality of the regulatory system, rule of law, voice and accountability, and expropriation risk are inversely related to poverty but their effect on poverty is via average income rather than income distribution. PMID:20645460

  8. Institute for Mechanical Engineering

    NASA Astrophysics Data System (ADS)

    The Institute of Mechanical Engineering has the objectives of supporting in Canada the following activities: improvement of vehicles, propulsion systems, and transportation-related facilities and services; improvements in the design and operation of maritime engineering works; protection of the environment; enhancement of energy flexibility; advancement of firms engaged in manufacturing and resource extraction; and related programs of other government departments and agencies. In 1990-91 the Institute, which had changed its name that year from the Division of Mechanical Engineering, consolidated its research activities from nine laboratories to six programs. Activities in these six programs are described: Advanced Manufacturing Technology, Coastal Zone Engineering, Cold Regions Engineering, Combustion and Fluids Engineering, Ground Transportation Technology, and Machinery and Engine Technology.

  9. Transportation Institutional Plan

    SciTech Connect

    Not Available

    1986-08-01

    This Institutional Plan is divided into three chapters. Chapter 1 provides background information, discusses the purposes of the Plan and the policy guidance for establishing the transportation system, and describes the projected system and the plans for its integrated development. Chapter 2 discusses the major participants who must interact to build the system. Chapter 3 suggests mechanisms for interaction that will foster wide participation in program planning and implementation and provides a framework for managing and resolving the issues related to development and operation of the transportation system. A list of acronyms and a glossary are included for the reader's convenience. Also included in this Plan are four appendices. Of particular importance is Appendix A, which includes detailed discussion of specific transportation issues. Appendices B, C, and D provide supporting material to assist the reader in understanding the roles of the involved institutions.

  10. A case in support of implementing innovative bio-processes in the metal mining industry.

    PubMed

    Sánchez-Andrea, Irene; Stams, Alfons J M; Weijma, Jan; Gonzalez Contreras, Paula; Dijkman, Henk; Rozendal, Rene A; Johnson, D Barrie

    2016-06-01

    The metal mining industry faces many large challenges in future years, among which is the increasing need to process low-grade ores as accessible higher grade ores become depleted. This is against a backdrop of increasing global demands for base and precious metals, and rare earth elements. Typically about 99% of solid material hauled to, and ground at, the land surface currently ends up as waste (rock dumps and mineral tailings). Exposure of these to air and water frequently leads to the formation of acidic, metal-contaminated run-off waters, referred to as acid mine drainage, which constitutes a severe threat to the environment. Formation of acid drainage is a natural phenomenon involving various species of lithotrophic (literally 'rock-eating') bacteria and archaea, which oxidize reduced forms of iron and/or sulfur. However, other microorganisms that reduce inorganic sulfur compounds can essentially reverse this process. These microorganisms can be applied on industrial scale to precipitate metals from industrial mineral leachates and acid mine drainage streams, resulting in a net improvement in metal recovery, while minimizing the amounts of leachable metals to the tailings storage dams. Here, we advocate that more extensive exploitation of microorganisms in metal mining operations could be an important way to green up the industry, reducing environmental risks and improving the efficiency and the economy of metal recovery. PMID:27190293

  11. Bond and fracture strength of metal-ceramic restorations formed by selective laser sintering

    PubMed Central

    Bae, Eun-Jeong; Kim, Woong-Chul; Kim, Hae-Young

    2014-01-01

    PURPOSE The purpose of this study was to compare the fracture strength of the metal and the bond strength in metal-ceramic restorations produced by selective laser sintering (SLS) and by conventional casting (CAST). MATERIALS AND METHODS Non-precious alloy (StarLoy C, DeguDent, Hanau, Germany) was used in CAST group and metal powder (SP2, EOS GmbH, Munich, Germany) in SLS group. Metal specimens in the form of sheets (25.0 × 3.0 × 0.5 mm) were produced in accordance with ISO 9693:1999 standards (n=30). To measure the bond strength, ceramic was fired on a metal specimen and then three-point bending test was performed. In addition, the metal fracture strength was measured by continuing the application of the load. The values were statistically analyzed by performing independent t-tests (α=.05). RESULTS The mean bond strength of the SLS group (50.60 MPa) was higher than that of the CAST group (46.29 MPa), but there was no statistically significant difference. The metal fracture strength of the SLS group (1087.2 MPa) was lower than that of the CAST group (2399.1 MPa), and this difference was statistically significant. CONCLUSION In conclusion the balling phenomenon and the gap formation of the SLS process may increase the metal-ceramic bond strength. PMID:25177469

  12. Asteroid 1986 DA: Radar evidence for a metallic composition

    NASA Technical Reports Server (NTRS)

    Ostro, Steven J.; Campbell, D. B.; Chandler, J. F.; Hine, A. A.; Hudson, R. S.; Rosema, K. D.; Shapiro, Irwin I.

    1991-01-01

    Radar observations of the near-Earth asteroid 1986 DA were carried out at the Arecibo Observatory in April 1986, two months after its discovery. Radar results are consistent with the hypothesis that 1986 HA is a piece of NiFe metal derived from the interior of a much larger object that melted, differentiated, cooled and subsequently was disrupted in a catastrophic collision. This 2-km asteroid might be (or have been part of) the parent body of some iron meteorites. Or 1986 DA might share the parentage and/or part of the dynamical history of some meteorites without ever having contributed any of its own ejecta to our meteorite sample. Analysis of the samples returned from 1986 DA might ultimately involve economic considerations. Meteoritic metal is mostly iron with about 8 percent nickel, but also contains substantial concentrations of precious and strategic metals, including approx. 1 ppm of gold and approx. 10 ppm of platinum group elements. If these abundances apply to 1986 DA, it contains some 10(exp 16) g of iron, 10 (exp 15) g of nickel, 10(exp 11) g of platinum group metals, and 10(exp 10) g of gold.

  13. Acceptorless dehydrogenation of small molecules through cooperative base metal catalysis

    PubMed Central

    West, Julian G.; Huang, David; Sorensen, Erik J.

    2015-01-01

    The dehydrogenation of unactivated alkanes is an important transformation both in industrial and biological systems. Recent efforts towards this reaction have revolved around high temperature, organometallic C–H activation by noble metal catalysts that produce alkenes and hydrogen gas as the sole products. Conversely, natural desaturase systems proceed through stepwise hydrogen atom transfer at physiological temperature; however, these transformations require a terminal oxidant. Here we show combining tetra-n-butylammonium decatungstate (TBADT) and cobaloxime pyridine chloride (COPC) can catalytically dehydrogenate unactivated alkanes and alcohols under near-UV irradiation at room temperature with hydrogen as the sole by-product. This noble metal-free process follows a nature-inspired pathway of high- and low-energy hydrogen atom abstractions. The hydrogen evolution ability of cobaloximes is leveraged to render the system catalytic, with cooperative turnover numbers up to 48 and yields up to 83%. Our results demonstrate how cooperative base metal catalysis can achieve transformations previously restricted to precious metal catalysts. PMID:26656087

  14. Acceptorless dehydrogenation of small molecules through cooperative base metal catalysis.

    PubMed

    West, Julian G; Huang, David; Sorensen, Erik J

    2015-01-01

    The dehydrogenation of unactivated alkanes is an important transformation both in industrial and biological systems. Recent efforts towards this reaction have revolved around high temperature, organometallic C-H activation by noble metal catalysts that produce alkenes and hydrogen gas as the sole products. Conversely, natural desaturase systems proceed through stepwise hydrogen atom transfer at physiological temperature; however, these transformations require a terminal oxidant. Here we show combining tetra-n-butylammonium decatungstate (TBADT) and cobaloxime pyridine chloride (COPC) can catalytically dehydrogenate unactivated alkanes and alcohols under near-UV irradiation at room temperature with hydrogen as the sole by-product. This noble metal-free process follows a nature-inspired pathway of high- and low-energy hydrogen atom abstractions. The hydrogen evolution ability of cobaloximes is leveraged to render the system catalytic, with cooperative turnover numbers up to 48 and yields up to 83%. Our results demonstrate how cooperative base metal catalysis can achieve transformations previously restricted to precious metal catalysts. PMID:26656087

  15. Metal Detectors.

    ERIC Educational Resources Information Center

    Harrington-Lueker, Donna

    1992-01-01

    Schools that count on metal detectors to stem the flow of weapons into the schools create a false sense of security. Recommendations include investing in personnel rather than hardware, cultivating the confidence of law-abiding students, and enforcing discipline. Metal detectors can be quite effective at afterschool events. (MLF)

  16. Metal-on-Metal Hip Resurfacing Arthroplasty

    PubMed Central

    Sehatzadeh, S; Kaulback, K; Levin, L

    2012-01-01

    Background Metal-on-metal (MOM) hip resurfacing arthroplasty (HRA) is in clinical use as an appropriate alternative to total hip arthroplasty in young patients. In this technique, a metal cap is placed on the femoral head to cover the damaged surface of the bone and a metal cup is placed in the acetabulum. Objectives The primary objective of this analysis was to compare the revision rates of MOM HRA using different implants with the benchmark set by the National Institute of Clinical Excellence (NICE). The secondary objective of this analysis was to review the literature regarding adverse biological effects associated with implant material. Review Methods A literature search was performed on February 13, 2012, to identify studies published from January 1, 2009, to February 13, 2012. Results The revision rates for MOM HRA using 6 different implants were reviewed. The revision rates for MOM HRA with 3 implants met the NICE criteria, i.e., a revision rate of 10% or less at 10 years. Two implants had short-term follow-ups and MOM HRA with one of the implants failed to meet the NICE criteria. Adverse tissue reactions resulting in failure of the implants have been reported by several studies. With a better understanding of the factors that influence the wear rate of the implants, adverse tissue reactions and subsequent implant failure can be minimized. Many authors have suggested that patient selection and surgical technique affect the wear rate and the risk of tissue reactions. The biological effects of high metal ion levels in the blood and urine of patients with MOM HRA implants are not known. Studies have shown an increase in chromosomal aberrations in patients with MOM articulations, but the clinical implications and long-term consequences of this increase are still unknown. Epidemiological studies have shown that patients with MOM HRA implants did not have an overall increase in mortality or risk of cancer. There is insufficient clinical data to confirm the

  17. INSTITUTION - DYNAMAP V.12.2

    EPA Science Inventory

    GDT Institutions represents point locations within New England for common institution landmark types including hospitals, educational institutions, religious institutions, government centers, and cemeteries

  18. Metal oxide films on metal

    DOEpatents

    Wu, Xin D.; Tiwari, Prabhat

    1995-01-01

    A structure including a thin film of a conductive alkaline earth metal oxide selected from the group consisting of strontium ruthenium trioxide, calcium ruthenium trioxide, barium ruthenium trioxide, lanthanum-strontium cobalt oxide or mixed alkaline earth ruthenium trioxides thereof upon a thin film of a noble metal such as platinum is provided.

  19. Spaceborne Photonics Institute

    NASA Technical Reports Server (NTRS)

    Venable, D. D.; Farrukh, U. O.; Han, K. S.; Hwang, I. H.; Jalufka, N. W.; Lowe, C. W.; Tabibi, B. M.; Lee, C. J.; Lyons, D.; Maclin, A.

    1994-01-01

    This report describes in chronological detail the development of the Spaceborne Photonics Institute as a sustained research effort at Hampton University in the area of optical physics. This provided the research expertise to initiate a PhD program in Physics. Research was carried out in the areas of: (1) modelling of spaceborne solid state laser systems; (2) amplified spontaneous emission in solar pumped iodine lasers; (3) closely simulated AM0 CW solar pumped iodine laser and repeatedly short pulsed iodine laser oscillator; (4) a materials spectroscopy and growth program; and (5) laser induced fluorescence and atomic and molecular spectroscopy.

  20. Metal Coatings

    NASA Technical Reports Server (NTRS)

    1994-01-01

    During the Apollo Program, General Magnaplate Corporation developed process techniques for bonding dry lubricant coatings to space metals. The coatings were not susceptible to outgassing and offered enhanced surface hardness and superior resistance to corrosion and wear. This development was necessary because conventional lubrication processes were inadequate for lightweight materials used in Apollo components. General Magnaplate built on the original technology and became a leader in development of high performance metallurgical surface enhancement coatings - "synergistic" coatings, - which are used in applications from pizza making to laser manufacture. Each of the coatings is designed to protect a specific metal or group of metals to solve problems encountered under operating conditions.

  1. Institutional Repositories: The Experience of Master's and Baccalaureate Institutions

    ERIC Educational Resources Information Center

    Markey, Karen; St. Jean, Beth; Soo, Young Rieh; Yakel, Elizabeth; Kim, Jihyun

    2008-01-01

    In 2006, MIRACLE Project investigators censused library directors at all U.S. academic institutions about their activities planning, pilot testing, and implementing the institutional repositories on their campuses. Out of 446 respondents, 289 (64.8 percent) were from master's and baccalaureate institutions (M&BIs) where few operational…

  2. Institutional Repositories at Small Institutions in America: Some Current Trends

    ERIC Educational Resources Information Center

    Nykanen, Melissa

    2011-01-01

    The research reported in this article was undertaken to determine the level of implementation of institutional repositories (IRs) at small institutions enrolling fewer than 10,000 students. The study analyzed quantitative and qualitative data from IRs at a number of small institutions with the aim of observing relevant patterns and trends that may…

  3. Institutional Repositories in Indian Universities and Research Institutes: A Study

    ERIC Educational Resources Information Center

    Krishnamurthy, M.; Kemparaju, T. D.

    2011-01-01

    Purpose: The purpose of this paper is to report on a study of the institutional repositories (IRs) in use in Indian universities and research institutes. Design/methodology/approach: Repositories in various institutions in India were accessed and described in a standardised way. Findings: The 20 repositories studied covered collections of diverse…

  4. Institutional Churn: Institutional Change in United Kingdom Higher Education

    ERIC Educational Resources Information Center

    Tight, Malcolm

    2013-01-01

    This article considers how higher education institutions change over time, using the United Kingdom system as an exemplar, and focusing on the 15-year period between 1994/95 and 2009/10. While there are many aspects of institutional change worthy of study, the focus here is on how institutions appear to others. Thus, the article examines the…

  5. International Security Institutions, Domestic Politics, and Institutional Legitimacy

    ERIC Educational Resources Information Center

    Chapman, Terrence L.

    2007-01-01

    Scholars have devoted considerable attention to the informational role of international institutions. However, several questions about the informational aspects of institutional behavior remain underexplored: What determines how audiences respond to institutional decisions? Through what channels does information provision affect foreign policy? To…

  6. [Antipsychotics in geriatric institutions].

    PubMed

    Szulik, Judith

    2007-01-01

    The present paper approaches the use of antipsychotics in elder people in general, and particularly in geriatric institutions. During the last few years, prescription of antipsychotics in geriatric institutions increased, especially because of the availability of the atypicals, and their use was extended beyond the indications these drugs had been approved for. In dementia they are suggested for treatment of behavioral symptoms, despite having been approved only for cases of aggressiveness and risk of damage. There is a common tendency of perpetuating antipsychotic medication in elder people, with its consequent collateral effects as well. Few years ago, the increase of both risk of cerebrovascular events and of mortality in dementia patients treated with atypical agents was noticed. This generated controversy regarding their use in those kind of patients. Diverse factors associated to caregivers affect the decision of prescribing an antipsychotic in elder people. Non-pharmacological interventions are the first choice when treating behavioral symptoms; pharmacological interventions must take place with the lowest doses possible, with limited durations. PMID:18273435

  7. Draft Transportation Institutional Plan

    SciTech Connect

    Not Available

    1985-09-01

    The Department of Energy recognizes that the success of its program to develop and implement a national system for nuclear waste management and disposal depends on broad-based public understanding and acceptance. While each program element has its particular sensitivity, the transportation of the waste may potentially affect the greatest number of people, and accordingly is highly visible and potentially issue-laden. Therefore, the Office of Civilian Radioactive Waste Management has developed this Transportation Institutional Plan to lay the foundation for interaction among all interested parties for the purpose of identifying and resolving issues of concern. The Plan is divided into four chapters. Chapter 1 provides bachground information and discusses the purpose of the Plan and the policy guidance for establishing the transportation system. Chapter 2 introduces the major participants who must interact to build both the system itself and the consensus philosophy that is essential for effective operations. Chapter 3 suggests mechanisms for interaction that will ensure wide participation in program planning and implementation. And, finally, Chapter 4 suggests a framework for managing and resolving the issues related to development and operation of the transportation system. A list of acronyms and a glossary are included for the reader's convenience. The Plan's appendices provide supporting material to assist the reader in understanding the roles of the involved institutions. 4 figs., 1 tab.

  8. Impact of metals on the environment due to technical accident at Aurul Baia Mare, Romania.

    PubMed

    Michnea, A; Gherheş, I

    2001-01-01

    The S.C. Aurul S.A. is a joint venture company owned by the Esmeralda from Australia and the "Remin" National Company of Precious and Non-ferrous Metals in Romania, established in 1992. The design concept was to transport the mining waste away from the city, while the gold and silver in the tailings could be recovered, using efficient and modern technology that was not available at the time the dam was established. On 30 January, 2000, at 22.00, the dam burst and released 100,000 cubic meters of tailing pulp, heavily contaminated with cyanide and cyanide complexes, especially with copper, into the Lapus and Somes tributaries of the river Tisa. The paper deals with the impact of metals on the environment associated with their presence in surface waters, river sediments and soils. PMID:11764854

  9. Body vibrational spectra of metal flute models

    NASA Astrophysics Data System (ADS)

    Hurtgen, Clare M.; Lawson, Dewey T.

    2002-11-01

    For years, flutists have argued over the tonal advantages of using different precious metals for their instruments. Occasionally, scientists have entered the fray and attempted to offer an objective point of view based on experimental measurements. However, their research often involved actual instruments and performers, ignoring variations in wall thickness, craftsmanship, and human consistency. These experiments have been conducted using a variety of methods; all have concluded that wall material has no effect on tone. This paper approaches the question using simple tubular models, excited by a wind source through a fipple mouthpiece. The amplitude and phase of the harmonic components of the body vibrational signal were measured with a stereo cartridge. Results demonstrated the existence of complex patterns of wall vibrations in the vicinity of a tone hole lattice, at frequencies that match significant harmonics of the air column. Additionally, the tube wall was found to expand in a nonuniform or ''elliptical'' manner due to the asymmetry of the tone holes. While this method is somewhat removed from direct musical applications, it can provide an objective, quantitative basis for assessing the source of differences among flutes. [Work financed by two Undergraduate Research Support grants from Duke University.

  10. Metals 2000

    SciTech Connect

    Allison, S.W.; Rogers, L.C.; Slaughter, G.; Boensch, F.D.; Claus, R.O.; de Vries, M.

    1993-05-01

    This strategic planning exercise identified and characterized new and emerging advanced metallic technologies in the context of the drastic changes in global politics and decreasing fiscal resources. In consideration of a hierarchy of technology thrusts stated by various Department of Defense (DOD) spokesmen, and the need to find new and creative ways to acquire and organize programs within an evolving Wright Laboratory, five major candidate programs identified are: C-17 Flap, Transport Fuselage, Mach 5 Aircraft, 4.Fighter Structures, and 5. Missile Structures. These results were formed by extensive discussion with selected major contractors and other experts, and a survey of advanced metallic structure materials. Candidate structural applications with detailed metal structure descriptions bracket a wide variety of uses which warrant consideration for the suggested programs. An analysis on implementing smart skins and structures concepts is given from a metal structures perspective.

  11. Differentiation of Higher Education Institutions.

    ERIC Educational Resources Information Center

    Cazenave, P.; Lapointe, S.

    1983-01-01

    Historical and political influences in the trend toward diversification in French universities are traced. Related issues discussed include institutional versus governmental preferences, institutional functions (curriculum, vocational training, research), and implications for the quality and democratization of higher education. (MSE)

  12. Institutional Research with "Smart Machines."

    ERIC Educational Resources Information Center

    Mason, Thomas R.

    1985-01-01

    Artificial intelligence programing for computers is advancing rapidly. The translation of databases into an institutional research knowledge base is explored, including the heuristic knowledge of institutional research experience. (Author/MLW)

  13. NEWS: Institute news

    NASA Astrophysics Data System (ADS)

    2000-07-01

    When Mary took up her appointment in the Institute's Education Department in June 1997, she indicated that she wished to return to teaching in two or three years. We have just heard that in September she will be joining the staff of the Science Department at Camden Girls' School, London. Mary's departure from the Institute is a great loss to the Department, where she has worked tirelessly, and with great imagination, to support those who teach physics at all secondary levels - and at primary level too when the opportunity presented itself. She has made tremendous contributions to the careers side of the Department's work, supporting careers events, providing informal training for others willing to do the same, helping to develop new careers materials and identifying people whom the Institute could use as role models or as the subject of case studies in print or electronic publications. Mary has been equally happy and willing to support pupils, students and teachers, and has been a wonderful role model herself, coming from an industrial research background, training for teaching after a career break and willing and able to teach biology, chemistry and design technology as well as physics. Mary has also written and edited Phases virtually single-handed. We are delighted to hear that Mary will continue to support the department's work as one of its teacher `volunteers'. Ilya Eigenbrot We are pleased to report that Ilya Eigenbrot, who will be known to some through his work at the Royal Institution and his appearances at the Christmas Lectures in a technical support role, has agreed to give the IOP Schools (touring) Lecture next year. The subject will be Lasers and this will follow nicely on to Zbig's lecture this year. Resources (print) Physics on Course The tenth issue of the Institute's popular guide to higher education, Physics on Course 2001, will be published early in July and distributed to all schools and colleges in the United Kingdom and the Republic of

  14. Efficient selective catalytic reduction of NO by novel carbon-doped metal catalysts made from electroplating sludge.

    PubMed

    Zhang, Jia; Zhang, Jingyi; Xu, Yunfeng; Su, Huimin; Li, Xiaoman; Zhou, Ji Zhi; Qian, Guangren; Li, Li; Xu, Zhi Ping

    2014-10-01

    Electroplating sludges, once regarded as industrial wastes, are precious resources of various transition metals. This research has thus investigated the recycling of an electroplating sludge as a novel carbon-doped metal (Fe, Ni, Mg, Cu, and Zn) catalyst, which was different from a traditional carbon-supported metal catalyst, for effective NO selective catalytic reduction (SCR). This catalyst removed >99.7% NO at a temperature as low as 300 °C. It also removed NO steadily (>99%) with a maximum specific accumulative reduced amount (MSARA) of 3.4 mmol/g. Gas species analyses showed that NO removal was accompanied by evolving N2 and CO2. Moreover, in a wide temperature window, the sludge catalyst showed a higher CO2 selectivity (>99%) than an activated carbon-supported metal catalyst. Structure characterizations revealed that carbon-doped metal was transformed to metal oxide in the sludge catalyst after the catalytic test, with most carbon (2.33 wt %) being consumed. These observations suggest that NO removal over the sludge catalyst is a typical SCR where metals/metal oxides act as the catalytic center and carbon as the reducing reagent. Therefore, our report probably provides an opportunity for high value-added utilizations of heavy-metal wastes in mitigating atmospheric pollutions. PMID:25191790

  15. Generation of copper rich metallic phases from waste printed circuit boards.

    PubMed

    Cayumil, R; Khanna, R; Ikram-Ul-Haq, M; Rajarao, R; Hill, A; Sahajwalla, V

    2014-10-01

    The rapid consumption and obsolescence of electronics have resulted in e-waste being one of the fastest growing waste streams worldwide. Printed circuit boards (PCBs) are among the most complex e-waste, containing significant quantities of hazardous and toxic materials leading to high levels of pollution if landfilled or processed inappropriately. However, PCBs are also an important resource of metals including copper, tin, lead and precious metals; their recycling is appealing especially as the concentration of these metals in PCBs is considerably higher than in their ores. This article is focused on a novel approach to recover copper rich phases from waste PCBs. Crushed PCBs were heat treated at 1150°C under argon gas flowing at 1L/min into a horizontal tube furnace. Samples were placed into an alumina crucible and positioned in the cold zone of the furnace for 5 min to avoid thermal shock, and then pushed into the hot zone, with specimens exposed to high temperatures for 10 and 20 min. After treatment, residues were pulled back to the cold zone and kept there for 5 min to avoid thermal cracking and re-oxidation. This process resulted in the generation of a metallic phase in the form of droplets and a carbonaceous residue. The metallic phase was formed of copper-rich red droplets and tin-rich white droplets along with the presence of several precious metals. The carbonaceous residue was found to consist of slag and ∼30% carbon. The process conditions led to the segregation of hazardous lead and tin clusters in the metallic phase. The heat treatment temperature was chosen to be above the melting point of copper; molten copper helped to concentrate metallic constituents and their separation from the carbonaceous residue and the slag. Inert atmosphere prevented the re-oxidation of metals and the loss of carbon in the gaseous fraction. Recycling e-waste is expected to lead to enhanced metal recovery, conserving natural resources and providing an environmentally

  16. Institutional Effectiveness and Student Success.

    ERIC Educational Resources Information Center

    Kreider, Paul E.; And Others

    Since the early 1980's, the primary institutional mission of Mount Hood Community College (MHCC) in Gresham, Oregon, has been identified as student success. Toward that end, the college has instituted an ongoing systematic review of instructional program improvement and implemented institutional strategic planning directly linked to budget…

  17. A Primer on Institutional Research.

    ERIC Educational Resources Information Center

    Muffo, John A., Ed.; McLaughlin, Gerald W., Ed.

    The state-of-the-art in 10 areas of institutional research is considered in this collection of 10 articles. Of concern are: student attrition and retention, academic program evaluation, financial issues and economic impacts of higher education, institutional self-study and regional accreditation, peer studies of institutions, statistical packages…

  18. National Space Biomedical Research Institute

    NASA Technical Reports Server (NTRS)

    2003-01-01

    This report outlines the activities of the National Space Biomedical Research Institute (NSBRI) during FY 2003, the sixth year of the NSBRI's programs. It is prepared in accordance with Cooperative Agreement NCC 9-58 between NASA's Lyndon B. Johnson Space Center (JSC) and the Institute's lead institution, Baylor College of Medicine.

  19. Improving Institutional Report Card Indicators

    ERIC Educational Resources Information Center

    McGowan, Veronica

    2016-01-01

    Institutional report cards are increasingly being used by higher educational institutions to present academic outcomes to external audiences of prospective students and parents, as well as program and institutional evaluators. While some prospective students are served by national transparency measures most users mine information from the…

  20. HISTORY OF THE LINGUISTIC INSTITUTE.

    ERIC Educational Resources Information Center

    HILL, ARCHIBALD A.

    THIS HISTORY, CONTAINED IN THE 1964 BULLETIN OF THE INDIANA UNIVERSITY LINGUISTIC INSTITUTE, GIVES AN ACCOUNT OF THE GROWTH AND DEVELOPMENT OF THE INSTITUTE FROM ITS FOUNDATION (IN 1928) AND EARLY SESSIONS UNDER THE DIRECTORSHIP OF EDGAR H. STURTEVANT. IT OFFERS A CONDENSED, YEAR-BY-YEAR DESCRIPTION OF THE INSTITUTE'S ACTIVITIES, MAKING NOTE OF…

  1. The Karst Waters Institute

    NASA Astrophysics Data System (ADS)

    The Karst Waters Institute (KWI) is a U.S. research organization that was formed to combine the skills of academic, governmental, and private sector specialists to solve existing karst water problems and anticipate future problems. KWI has been incorporated as a not-for-profit corporation in West Virginia to provide the human expertise and database needed to assist the nation in the preservation and utilization of its water resources. KWI plans to develop a core of resident and visiting scientists from across the nation and overseas, technicians, support staff, and graduate students. Its mission is to conduct research to improve our understanding of karst phenomena, to develop techniques to prevent environmental problems from occurring in karst areas, to assist in rectifying existing environmental problems, and to provide education and training for professionals and the general public on the risks and benefits of karst areas.

  2. Cyclotron Institute Upgrade Project

    SciTech Connect

    Clark, Henry; Yennello, Sherry; Tribble, Robert

    2014-08-26

    The Cyclotron Institute at Texas A&M University has upgraded its accelerator facilities to extend research capabilities with both stable and radioactive beams. The upgrade is divided into three major tasks: (1) re-commission the K-150 (88”) cyclotron, couple it to existing beam lines to provide intense stable beams into the K-500 experimental areas and use it as a driver to produce radioactive beams; (2) develop light ion and heavy ion guides for stopping radioactive ions created with the K-150 beams; and (3) transport 1+ ions from the ion guides into a charge-breeding electron-cyclotron-resonance ion source (CB-ECR) to produce highly-charged radioactive ions for acceleration in the K-500 cyclotron. When completed, the upgraded facility will provide high-quality re-accelerated secondary beams in a unique energy range in the world.

  3. A noble and single source precursor for the synthesis of metal-rich sulphides embedded in an N-doped carbon framework for highly active OER electrocatalysts.

    PubMed

    Barman, Barun Kumar; Nanda, Karuna Kar

    2016-04-12

    Here, we demonstrate a green and environment-friendly pyrolysis route for the synthesis of metal-rich sulphide embedded in an N-doped carbon (NC) framework in the absence of sulphide ions (S(2-)). The metal-chelate complex (tris(ethylenediamine) metal(ii) sulfate) serves as a new and single source precursor for the synthesis of earth abundant and non-precious hybrid structures such as metal-rich sulphides Co9S8@NC and Ni3S2@NC when M(II) = Co(2+) and Ni(2+) and counter sulphate (SO4(2-)) ions are the source of S. Both the hybrids show superior OER activity as compared to commercial RuO2. PMID:26999042

  4. Metal-free carbonaceous electrocatalysts and photocatalysts for water splitting.

    PubMed

    Xu, You; Kraft, Markus; Xu, Rong

    2016-05-31

    Water splitting driven by sunlight or renewable resource-derived electricity has attracted great attention for sustainable production of hydrogen from water. Current research interest in this field is focused on the development of earth-abundant photo- or electrocatalytic materials with high activity and long-term stability for hydrogen and/or oxygen evolution reactions. Due to their unique properties and characteristics, carbon and related carbon-based materials show great potential to replace some of the existing precious metal catalysts in water splitting technology. This tutorial review summarizes the recent significant progress in the fabrication and application of metal-free carbonaceous materials as photo- or electrocatalysts for water splitting. Synthetic strategies and applications of various carbonaceous materials, including graphitic carbon nitride (g-C3N4), graphene, carbon nanotubes (CNTs) as well as other forms of carbon-containing materials, for electrochemical or photochemical water splitting are presented, accompanied by a discussion of the key scientific issues and prospects for the future development of metal-free photo- and electrocatalysts. PMID:27094875

  5. Metallic Hydrogen

    NASA Astrophysics Data System (ADS)

    Silvera, Isaac; Zaghoo, Mohamed; Salamat, Ashkan

    2015-03-01

    Hydrogen is the simplest and most abundant element in the Universe. At high pressure it is predicted to transform to a metal with remarkable properties: room temperature superconductivity, a metastable metal at ambient conditions, and a revolutionary rocket propellant. Both theory and experiment have been challenged for almost 80 years to determine its condensed matter phase diagram, in particular the insulator-metal transition. Hydrogen is predicted to dissociate to a liquid atomic metal at multi-megabar pressures and T =0 K, or at megabar pressures and very high temperatures. Thus, its predicted phase diagram has a broad field of liquid metallic hydrogen at high pressure, with temperatures ranging from thousands of degrees to zero Kelvin. In a bench top experiment using static compression in a diamond anvil cell and pulsed laser heating, we have conducted measurements on dense hydrogen in the region of 1.1-1.7 Mbar and up to 2200 K. We observe a first-order phase transition in the liquid phase, as well as sharp changes in optical transmission and reflectivity when this phase is entered. The optical signature is that of a metal. The mapping of the phase line of this transition is in excellent agreement with recent theoretical predictions for the long-sought plasma phase transition to metallic hydrogen. Research supported by the NSF, Grant DMR-1308641, the DOE Stockpile Stewardship Academic Alliance Program, Grant DE-FG52-10NA29656, and NASA Earth and Space Science Fellowship Program, Award NNX14AP17H.

  6. Institutional analysis for energy policy

    SciTech Connect

    Morris, F.A.; Cole, R.J.

    1980-07-01

    This report summarizes principles, techniques, and other information for doing institutional analyses in the area of energy policy. The report was prepared to support DOE's Regional Issues Identification and Assessment (RIIA) program. RIIA identifies environmental, health, safety, socioeconomic, and institutional issues that could accompany hypothetical future scenarios for energy consumption and production on a regional basis. Chapter 1 provides some theoretical grounding in institutional analysis. Chapter 2 provides information on constructing institutional maps of the processes for bringing on line energy technologies and facilities contemplated in RIIA scenarios. Chapter 3 assesses the institutional constraints, opportunities, and impacts that affect whether these technologies and facilities would in fact be developed. Chapters 4 and 5 show how institutional analysis can support use of exercises such as RIIA in planning institutional change and making energy policy choices.

  7. Teacher Enhancement Institute

    NASA Technical Reports Server (NTRS)

    Marshall-Bradley, Tina

    1994-01-01

    During the 1980's, a period of intense concern over educational quality in the United States, few indicators of U.S. student achievement garnered the interest of policy makers and pundits as successfully as the results of international testing in mathematics and science. This concern was so great that as a part of the Goals 2000 initiative, President George Bush indicated that 'By the year 2000, U.S. students should be first in the world in mathematics and science.' The Clinton Administration is placing a major emphasis, not only on rigorous academic standards and creating a new system for assessing students' progress, but also including professional development as a major focus. The argument being that teachers need more sustained, intensive training to prepare them to teach to higher standards. Executive order 12821 mandates that national laboratories 'assist in the mathematics and science education of our Nation's students, teachers, parents and the public by establishing programs at their agency to provide for training elementary and secondary school teachers to improve their knowledge of mathematics and science'. These and other issues led to the development of ideas for a project that addresses the need for excellence in mathematics, science and technology instruction. In response to these initiatives the NASA/LaRC Teacher Enhancement Institute was proposed. The TEI incorporated systemic reform perspectives, enhanced content knowledge for teachers, and teacher preparation. Emphasis was also placed on recruiting those educators who teach in impoverished urban school districts with at-risk student populations who have been traditionally under represented in science, mathematics, technology and engineering. Participants in the Teacher Enhancement Institute were 37 teachers from grades K-8, teaching in Region 2 in the state of Virginia, as well as 2 preservice teachers from Norfolk State University and one teacher from Dublin, Virginia, where a Science

  8. NEWS: Institute news

    NASA Astrophysics Data System (ADS)

    2000-03-01

    Recognition for teachers The Institute of Physics has continued its programme of recognition for inspiring teachers with nine Teachers Awards in 2000, one at primary level and eight at secondary. The quality and quantity of nominations for secondary awards was very encouraging, especially those nominations made by students, but the number of nominations for teachers in the primary sector was disappointing. The award winners are: Teacher of Primary Science Graham Tomlinson, Cockermouth School, Cumbria Gill Stafford, Greens Norton Church of England Primary School, Towcester, Northants Teachers of Physics (Secondary) John Allen, All Hallows High School, Penwortham, Preston Tim Gamble, Lings Upper School, Northampton Denise Gault, Dalriada School, Ballymoney, Co Antrim Ian Lovat, Ampleforth College, North Yorkshire David Smith, Highgate School, North London Clive Thomas, Newcastle Emlyn Comprehensive School Graham Tomlinson, Cockermouth School, Cumbria Mark Travis, Cape Cornwall School, St Just, Cornwall If you know a teacher in a local primary school who is doing an exceptional job in motivating youngsters and colleagues in the teaching and learning of science, why not consider nominating them for an award? Further details can be obtained from the Institute's Education Department (Steven Chapman) by post or e-mail (schools.education@iop.org .) Annual Congress More details are now available on the various activities at this event taking place on 27 - 30 March 2000 at the Brighton Conference Centre. Among those organized by the Education Department are general science and technology hands-on activities for pupils aged 10 to 12 and more specific physics activities on Static Electricity for older students: * A series of short talks with hands-on demonstrations of music and musical instruments given by musicians, manufacturers and physicists. * A chance for students in years 9 to 13 to experience music making from the professionals' perspective. Mornings, 28 to 30 March

  9. The California Hazards Institute

    NASA Astrophysics Data System (ADS)

    Rundle, J. B.; Kellogg, L. H.; Turcotte, D. L.

    2006-12-01

    California's abundant resources are linked with its natural hazards. Earthquakes, landslides, wildfires, floods, tsunamis, volcanic eruptions, severe storms, fires, and droughts afflict the state regularly. These events have the potential to become great disasters, like the San Francisco earthquake and fire of 1906, that overwhelm the capacity of society to respond. At such times, the fabric of civic life is frayed, political leadership is tested, economic losses can dwarf available resources, and full recovery can take decades. A patchwork of Federal, state and local programs are in place to address individual hazards, but California lacks effective coordination to forecast, prevent, prepare for, mitigate, respond to, and recover from, the harmful effects of natural disasters. Moreover, we do not know enough about the frequency, size, time, or locations where they may strike, nor about how the natural environment and man-made structures would respond. As California's population grows and becomes more interdependent, even moderate events have the potential to trigger catastrophes. Natural hazards need not become natural disasters if they are addressed proactively and effectively, rather than reactively. The University of California, with 10 campuses distributed across the state, has world-class faculty and students engaged in research and education in all fields of direct relevance to hazards. For that reason, the UC can become a world leader in anticipating and managing natural hazards in order to prevent loss of life and property and degradation of environmental quality. The University of California, Office of the President, has therefore established a new system-wide Multicampus Research Project, the California Hazards Institute (CHI), as a mechanism to research innovative, effective solutions for California. The CHI will build on the rich intellectual capital and expertise of the Golden State to provide the best available science, knowledge and tools for

  10. Metal nanoshells.

    PubMed

    Hirsch, Leon R; Gobin, Andre M; Lowery, Amanda R; Tam, Felicia; Drezek, Rebekah A; Halas, Naomi J; West, Jennifer L

    2006-01-01

    Metal nanoshells are a new class of nanoparticles with highly tunable optical properties. Metal nanoshells consist of a dielectric core nanoparticle such as silica surrounded by an ultrathin metal shell, often composed of gold for biomedical applications. Depending on the size and composition of each layer of the nanoshell, particles can be designed to either absorb or scatter light over much of the visible and infrared regions of the electromagnetic spectrum, including the near infrared region where penetration of light through tissue is maximal. These particles are also effective substrates for surface-enhanced Raman scattering (SERS) and are easily conjugated to antibodies and other biomolecules. One can envision a myriad of potential applications of such tunable particles. Several potential biomedical applications are under development, including immunoassays, modulated drug delivery, photothermal cancer therapy, and imaging contrast agents. PMID:16528617

  11. Metallized Products

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Since the early 1960's, virtually all NASA spacecraft have used metallized films for a variety of purposes, principally thermal radiation insulation. King Seeley manufactures a broad line of industrial and consumer oriented metallized film, fabric, paper and foam in single layer sheets and multi-layer laminates. A few examples, commercialized by MPI Outdoor Safety Products, are the three ounce Thermos Emergency Blanket which reflects and retains up to 80 percent of the user's body heat helping prevent post accident shock or keeping a person warm for hours under emergency cold weather conditions.

  12. Integrative Bioengineering Institute

    SciTech Connect

    Eddington, David; Magin,L,Richard; Hetling, John; Cho, Michael

    2009-01-09

    Microfabrication enables many exciting experimental possibilities for medicine and biology that are not attainable through traditional methods. However, in order for microfabricated devices to have an impact they must not only provide a robust solution to a current unmet need, but also be simple enough to seamlessly integrate into standard protocols. Broad dissemination of bioMEMS has been stymied by the common aim of replacing established and well accepted protocols with equally or more complex devices, methods, or materials. The marriage of a complex, difficult to fabricate bioMEMS device with a highly variable biological system is rarely successful. Instead, the design philosophy of my lab aims to leverage a beneficial microscale phenomena (e.g. fast diffusion at the microscale) within a bioMEMS device and adapt to established methods (e.g. multiwell plate cell culture) and demonstrate a new paradigm for the field (adapt instead of replace). In order for the field of bioMEMS to mature beyond novel proof-of-concept demonstrations, researchers must focus on developing systems leveraging these phenomena and integrating into standard labs, which have largely been ignored. Towards this aim, the Integrative Bioengineering Institute has been established.

  13. Recovery of dilute metal ions by biosorption on river algae and its component

    SciTech Connect

    Fujita, Toyohisa; Kogita, Hiroki; Mamiya, Mitsuo; Yen, W.T.

    1995-12-31

    Green algae taken from an acidic mine drainage and blue-green algae take from an alkaline hot spring stream were collected and tested for their ability to recover or remove dilute metal ions. Experimental results demonstrated that unwashed blue-green algae and washed green algae effectively adsorbed base metals ions and eluted the at pH 1. It was also found that washed and dried algae adsorbed precious metal ions more effectively than unwashed algae. For example, the washed and dried blue-green algae was capable of adsorbing 0.31 kg of gold pre kg of algae. The gold from tetrachloroaurate solution which was adsorbed on washed blue-green algae was found to change to a metallic state following initial metal binding. In the case of a dilute gold complex solution leached with thiourea, only a small amount of gold could be captured by algae. Further experiments were conducted on components of the algae, such as alginic acid, agar, cellulose and chitin and mixtures of these components, in order to determine their contribution to metal adsorption characteristics. However, a mixture of these two components demonstrated both good adsorption and desorption characteristics indicating an interaction between the individual components.

  14. 76 FR 174 - NIJ Draft Metal Detector Standards for Public Safety

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-03

    ... of Justice Programs NIJ Draft Metal Detector Standards for Public Safety AGENCY: National Institute of Justice. ACTION: Notice and request for comments on the Draft Metal Detector Standards for Public... the following draft standards for metal detectors: 1. Walk-through Metal Detector Standard for...

  15. NEWS: Institute news

    NASA Astrophysics Data System (ADS)

    2000-07-01

    When Mary took up her appointment in the Institute's Education Department in June 1997, she indicated that she wished to return to teaching in two or three years. We have just heard that in September she will be joining the staff of the Science Department at Camden Girls' School, London. Mary's departure from the Institute is a great loss to the Department, where she has worked tirelessly, and with great imagination, to support those who teach physics at all secondary levels - and at primary level too when the opportunity presented itself. She has made tremendous contributions to the careers side of the Department's work, supporting careers events, providing informal training for others willing to do the same, helping to develop new careers materials and identifying people whom the Institute could use as role models or as the subject of case studies in print or electronic publications. Mary has been equally happy and willing to support pupils, students and teachers, and has been a wonderful role model herself, coming from an industrial research background, training for teaching after a career break and willing and able to teach biology, chemistry and design technology as well as physics. Mary has also written and edited Phases virtually single-handed. We are delighted to hear that Mary will continue to support the department's work as one of its teacher `volunteers'. Ilya Eigenbrot We are pleased to report that Ilya Eigenbrot, who will be known to some through his work at the Royal Institution and his appearances at the Christmas Lectures in a technical support role, has agreed to give the IOP Schools (touring) Lecture next year. The subject will be Lasers and this will follow nicely on to Zbig's lecture this year. Resources (print) Physics on Course The tenth issue of the Institute's popular guide to higher education, Physics on Course 2001, will be published early in July and distributed to all schools and colleges in the United Kingdom and the Republic of

  16. METAL COMPOSITIONS

    DOEpatents

    Seybolt, A.U.

    1959-02-01

    Alloys of uranium which are strong, hard, and machinable are presented, These alloys of uranium contain bctween 0.1 to 5.0% by weight of at least one noble metal such as rhodium, palladium, and gold. The alloys may be heat treated to obtain a product with iniproved tensile and compression strengths,

  17. Heavy Metal.

    ERIC Educational Resources Information Center

    Shoemaker, W. Lee

    1998-01-01

    Discusses the advantages, both functional and economic, of using a standing-seam metal roof in both new roof installations and reroofing projects of educational facilities. Structural versus non-structural standing-seam roofs are described as are the types of insulation that can be added and roof finishes used. (GR)

  18. NEWS: Institute news

    NASA Astrophysics Data System (ADS)

    2000-03-01

    Recognition for teachers The Institute of Physics has continued its programme of recognition for inspiring teachers with nine Teachers Awards in 2000, one at primary level and eight at secondary. The quality and quantity of nominations for secondary awards was very encouraging, especially those nominations made by students, but the number of nominations for teachers in the primary sector was disappointing. The award winners are: Teacher of Primary Science Graham Tomlinson, Cockermouth School, Cumbria Gill Stafford, Greens Norton Church of England Primary School, Towcester, Northants Teachers of Physics (Secondary) John Allen, All Hallows High School, Penwortham, Preston Tim Gamble, Lings Upper School, Northampton Denise Gault, Dalriada School, Ballymoney, Co Antrim Ian Lovat, Ampleforth College, North Yorkshire David Smith, Highgate School, North London Clive Thomas, Newcastle Emlyn Comprehensive School Graham Tomlinson, Cockermouth School, Cumbria Mark Travis, Cape Cornwall School, St Just, Cornwall If you know a teacher in a local primary school who is doing an exceptional job in motivating youngsters and colleagues in the teaching and learning of science, why not consider nominating them for an award? Further details can be obtained from the Institute's Education Department (Steven Chapman) by post or e-mail (schools.education@iop.org .) Annual Congress More details are now available on the various activities at this event taking place on 27 - 30 March 2000 at the Brighton Conference Centre. Among those organized by the Education Department are general science and technology hands-on activities for pupils aged 10 to 12 and more specific physics activities on Static Electricity for older students: * A series of short talks with hands-on demonstrations of music and musical instruments given by musicians, manufacturers and physicists. * A chance for students in years 9 to 13 to experience music making from the professionals' perspective. Mornings, 28 to 30 March

  19. Institutional aspects of lake management

    NASA Astrophysics Data System (ADS)

    Born, Stephen M.; Rumery, Carolyn

    1989-01-01

    The major barriers to successful lake management are institutional. However, in contrast to the technical and limnological dimensions of lake management, the institutional aspects of managing lakes have received little attention. The institutional factors that are important for successful lake management outcomes are: overlapping areal jurisdiction among governmental units, fragmented functional program responsibilities, ineffective coordination, limited authority, financial constraints, private sector roles, and inadequate public awareness and consensus. The range of typical institutional problems confronting lake management are well illustrated through experiences from the state of Wisconsin, USA. Because lake management programs with institutional shortcomings rarely realize their goals, it is critical to assimilate, evaluate, and apply our experience to date with the institutional arrangements necessary to effectively manage lake resources.

  20. Composite metal membrane

    DOEpatents

    Peachey, Nathaniel M.; Dye, Robert C.; Snow, Ronny C.; Birdsell, Stephan A.

    1998-01-01

    A composite metal membrane including a first metal layer of Group IVB met or Group VB metals, the first metal layer sandwiched between two layers of an oriented metal of palladium, platinum or alloys thereof is provided together with a process for the recovery of hydrogen from a gaseous mixture including contacting a hydrogen-containing gaseous mixture with a first side of a nonporous composite metal membrane including a first metal of Group IVB metals or Group VB metals, the first metal layer sandwiched between two layers of an oriented metal of palladium, platinum or alloys thereof, and, separating hydrogen from a second side of the nonporous composite metal membrane.

  1. Composite metal membrane

    DOEpatents

    Peachey, N.M.; Dye, R.C.; Snow, R.C.; Birdsell, S.A.

    1998-04-14

    A composite metal membrane including a first metal layer of Group IVB met or Group VB metals, the first metal layer sandwiched between two layers of an oriented metal of palladium, platinum or alloys thereof is provided together with a process for the recovery of hydrogen from a gaseous mixture including contacting a hydrogen-containing gaseous mixture with a first side of a nonporous composite metal membrane including a first metal of Group IVB metals or Group VB metals, the first metal layer sandwiched between two layers of an oriented metal of palladium, platinum or alloys thereof, and, separating hydrogen from a second side of the nonporous composite metal membrane.

  2. Education in Young Offender Institutions and Secure Youth Care Institutions

    ERIC Educational Resources Information Center

    Smeets, Ed

    2014-01-01

    The main goal of this study was to gain a better insight into efforts made to provide optimum education to juveniles in young offender institutions and in secure youth care institutions, and into barriers with which educators are confronted in this process. Results show that for a substantial number of juveniles insufficient information is…

  3. Institutional Fact Book: Catalyst for an Integrated Institutional Research Program.

    ERIC Educational Resources Information Center

    Smith, Glynton

    1983-01-01

    Broad understanding of an institution is fundamental to strategic planning, and information and communication are integral parts of this understanding. An institutional fact book used at Georgia State University is discussed both as a basic information system and as a practical communication vehicle. (MLW)

  4. SOLUBILITY AND MOBILITY OF TOXIC METALS UNDER COMPLEX CONDITIONS

    EPA Science Inventory

    EPA Identifier: F8P11069
    Title: Solubility and Mobility of Toxic Metals Under Complex Conditions
    Fellow (Principal Investigator): Brandi N. Clark
    Institution: University of Missouri - Rolla
    EPA GRANT Representative: Georgette Bod...

  5. Budgetary Control Procedures for Institutions.

    ERIC Educational Resources Information Center

    Powell, Ray M.

    Budgetary control procedures for not-for-profit institutions are presented in this compilation of budgetary materials and ideas gathered at the Program for Institutional Administrators at the University of Notre Dame. Budgetary reporting and control are suggested as the most effective tools for coordinating and controlling the acquisition and use…

  6. Institutional Advertising in Higher Education.

    ERIC Educational Resources Information Center

    Kittle, Bart

    2000-01-01

    An exploratory study surveyed 59 colleges and universities concerning their advertising practices, specifically media usage, importance of communication objectives for institutional messages, and the importance of audiences targeted for advertising. All major media were used by most of the institutions. Communication objectives mentioned most…

  7. Distributed Learning and Institutional Restructuring.

    ERIC Educational Resources Information Center

    Hawkins, Brian L.

    1999-01-01

    Discusses the following challenges institutions must consider as they enter the new marketplace of distributed learning: library access, faculty workload, faculty incentives, faculty-support structures, intellectual property, articulation agreements, financial aid, pricing, cross-subsidization of programs, institutional loyalty and philanthropy,…

  8. The Institutional Relations Review, 1999.

    ERIC Educational Resources Information Center

    Institutional Relations Review, 1999

    1999-01-01

    The Alaska Commission on Postsecondary Education's (ACPE) Institutional Relations Review seeks to provide the postsecondary schools in Alaska with information that pertains to the daily involvement with the Alaska Student Loan (ASL) Programs, Institutional Authorization, Compliance Audit functions and other related subjects. Four issues were…

  9. Institutional Vision and Academic Advising

    ERIC Educational Resources Information Center

    Abelman, Robert; Molina, Anthony D.

    2006-01-01

    Quality academic advising in higher education is the product of a multitude of elements not the least of which is institutional vision. By recognizing and embracing an institution's concept of its capabilities and the kinds of educated human beings it is attempting to cultivate, advisors gain an invaluable apparatus to guide the provision of…

  10. The Institutional Relations Review, 1998.

    ERIC Educational Resources Information Center

    Institutional Relations Review, 1998

    1998-01-01

    The Alaska Commission on Postsecondary Education's (ACPE) Institutional Relations Review seeks to provide the postsecondary schools in Alaska with information that pertains to the daily involvement with the Alaska Student Loan Programs (ASLP), Institutional Authorization, Compliance Audit functions and other related subjects. Four issues were…

  11. Recommendations for Institutional Prematriculation Immunizations

    ERIC Educational Resources Information Center

    Journal of American College Health, 2006

    2006-01-01

    The "Recommendations for Institutional Prematriculation Immunizations" described in this article are provided to colleges and universities to facilitate the implementation of a comprehensive institutional prematriculation immunization policy. In response to changing epidemiology and the introduction of new vaccines, the American College Health…

  12. Managing Enrollments for Institutional Vitality.

    ERIC Educational Resources Information Center

    Hossler, Don

    1985-01-01

    The concept of enrollment management is gaining acceptance as a means of ensuring institutional vitality. Those responsible for enrollment management must have direct responsibility for: student marketing and recruitment, pricing and financial aid, academic and career advising, academic assistance programs, institutional research, orientation,…

  13. Journalism and Institutional Review Boards

    ERIC Educational Resources Information Center

    Dash, Leon

    2007-01-01

    The author opposes any Institutional Review Boards (IRBs) overseeing the work of journalism professors and journalism students in any academic institution. He argues that the tendency for IRBs to require anonymity for persons interviewed immediately reduces the credibility of any journalistic story. The composition of an IRB is questioned on…

  14. Assessing and Improving Institutional Effectiveness.

    ERIC Educational Resources Information Center

    Cameron, Kim S.

    Information to promote assessment of organizational effectiveness in colleges and universities is presented, along with an exercise to rank the effectiveness of 10 institutions. The exercise uses three types of criteria to indicate effectiveness: subjective ratings, data about students and activities, and institutional capacity and financial…

  15. Lotka's Law and Institutional Productivity.

    ERIC Educational Resources Information Center

    Kumar, Suresh; Sharma, Praveen; Garg, K. C.

    1998-01-01

    Examines the applicability of Lotka's Law, negative binomial distribution, and lognormal distribution for institutional productivity in the same way as it is to authors and their productivity. Results indicate that none of the distributions are applicable for institutional productivity in engineering sciences. (Author/LRW)

  16. Protocological Rhetoric: Intervening in Institutions

    ERIC Educational Resources Information Center

    Johnson, Nathan R.

    2014-01-01

    This article describes protocological rhetoric as a conceptual tool for exploring and changing institutions. Protocological rhetoric is an extension of two lines of thought: Porter, Sullivan, Blythe, Grabill, and Miles's institutional critique and Science & Technology Studies's (STS) concept of information infrastructure. As a result,…

  17. Managing the Public Service Institution

    ERIC Educational Resources Information Center

    Drucker, Peter F.

    1976-01-01

    Important factors in managing a public service institution include knowing the publics served, phasing out an old program when introducing a new one, defining the roles of administrators and professionals, integrating individuals and the institution, and making the public aware of the value of the service performed. (PF)

  18. Institutional Research and Management Challenges.

    ERIC Educational Resources Information Center

    Blai, Boris, Jr.

    In the midst of insistent demands for accountability, self-analysis by all educational institutions has become an urgent necessity. Long-range, comprehensive planning is an essential prerequisite for coping effectively with the rapid changes taking place in education, and institutional research is an essential element in such planning. For an…

  19. One-dimensional manganese-cobalt oxide nanofibres as bi-functional cathode catalysts for rechargeable metal-air batteries

    PubMed Central

    Jung, Kyu-Nam; Hwang, Soo Min; Park, Min-Sik; Kim, Ki Jae; Kim, Jae-Geun; Dou, Shi Xue; Kim, Jung Ho; Lee, Jong-Won

    2015-01-01

    Rechargeable metal-air batteries are considered a promising energy storage solution owing to their high theoretical energy density. The major obstacles to realising this technology include the slow kinetics of oxygen reduction and evolution on the cathode (air electrode) upon battery discharging and charging, respectively. Here, we report non-precious metal oxide catalysts based on spinel-type manganese-cobalt oxide nanofibres fabricated by an electrospinning technique. The spinel oxide nanofibres exhibit high catalytic activity towards both oxygen reduction and evolution in an alkaline electrolyte. When incorporated as cathode catalysts in Zn-air batteries, the fibrous spinel oxides considerably reduce the discharge-charge voltage gaps (improve the round-trip efficiency) in comparison to the catalyst-free cathode. Moreover, the nanofibre catalysts remain stable over the course of repeated discharge-charge cycling; however, carbon corrosion in the catalyst/carbon composite cathode degrades the cycling performance of the batteries. PMID:25563733

  20. One-dimensional manganese-cobalt oxide nanofibres as bi-functional cathode catalysts for rechargeable metal-air batteries.

    PubMed

    Jung, Kyu-Nam; Hwang, Soo Min; Park, Min-Sik; Kim, Ki Jae; Kim, Jae-Geun; Dou, Shi Xue; Kim, Jung Ho; Lee, Jong-Won

    2015-01-01

    Rechargeable metal-air batteries are considered a promising energy storage solution owing to their high theoretical energy density. The major obstacles to realising this technology include the slow kinetics of oxygen reduction and evolution on the cathode (air electrode) upon battery discharging and charging, respectively. Here, we report non-precious metal oxide catalysts based on spinel-type manganese-cobalt oxide nanofibres fabricated by an electrospinning technique. The spinel oxide nanofibres exhibit high catalytic activity towards both oxygen reduction and evolution in an alkaline electrolyte. When incorporated as cathode catalysts in Zn-air batteries, the fibrous spinel oxides considerably reduce the discharge-charge voltage gaps (improve the round-trip efficiency) in comparison to the catalyst-free cathode. Moreover, the nanofibre catalysts remain stable over the course of repeated discharge-charge cycling; however, carbon corrosion in the catalyst/carbon composite cathode degrades the cycling performance of the batteries. PMID:25563733