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At least 1,027 records · Page 57

Effectiveness of copper and bronze for zinc capture

A series of experiments was conducted to determine the efficacy of using copper and bronze sheet and screen under high vacuum conditions to capture zinc vapor. The experiments were conducted in a parametric manner using a fixed zinc vaporization temperature (350°C) but varying the filter temperature from ambient to 550°C. Consistent with previous work, metallic zinc was deposited at low temperatures, but the deposit was non-adherent. At an intermediate temperature range (350-450°C), the deposit formed an alloy with both copper and bronze materials. At higher temperatures (> 500°C) the zinc did not deposit on the surfaces likely due to its high vapor pressure. Additional testing to optimize the zinc 'getter' chemistry and surface condition is warranted.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Parameters for the Injection, Acceleration, and Extraction of Gold and Copper Ions in Booster, AGS, and RHIC

During the 2012 RHIC run, uranium, gold, and copper ions from EBIS were accelerated in Booster and AGS and delivered to RHIC for the physics program. In this note the nominal parameters for gold and copper are given. The parameters for uranium are given in a separate note. In order to achieve the desired number of ions per bunch in RHIC, it was necessary to merge bunches in both Booster and AGS.

43 PARTICLE ACCELERATORS↗

Effect of Thermal Processes on Copper‐Tin Alloys for Zinc Gettering

A contamination mitigation plan was initiated to address the discovery of radioactive zinc-65 in a glovebox. A near term solution was developed, installation of heated filters in the glovebox piping. This solution is effective at retaining the zinc in the currently contaminated area, but the gamma emitting contaminant is still present in a system designed for tritium beta. A project was initiated to develop a solution to contain the 65 Zn in the furnace module. Copper and bronze (a Cu/Sn alloy) were found to be candidate materials to combine with zinc-65 vapor, using thermodynamic calculations. A series of binary Cu/Sn alloys were developed (after determining that commercial alloys were unacceptable), that were found to be effective traps of zinc vapor. The task described in this report was undertaken to determine if the bronze substrates would retain their zinc gettering capability after being exposed to simulated extraction conditions with oxidizing and reducing gases. Pure copper and three bronze alloys were prepared, exposed to varying oxidation conditions from 250 to 450°C, then exposed to varying reduction conditions in He-H 2 from 250-450°C, and finally exposed to zinc vapor at 350°C for four hours. The samples were characterized using scanning electron microscopy, X-ray diffraction, differential thermal analysis, mass change, and visual observation. It was observed that the as fabricated samples and the reduced samples all retained their zinc gettering capacity while samples in the "as-oxidized" condition exhibited losses in zinc gettering capacity. Over the range of conditions tested, i.e., composition, oxidation temperature, and reduction temperature, no particular sample composition appeared better. Samples reduced at 350°C exhibited the greatest zinc capacity, although there were some testing anomalies associated with these samples. This work clearly demonstrated that the zinc gettering was not adversely affected by exposure to simulated process conditions and a full scale lithium and zinc trap should be fabricated for testing in the Tritium Extraction Facility.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Comparative Assessment of Copper-Coated Kapton: Analysis of Microclad from Several Manufacturing Lots

Microclad is a composite material consisting of a thin copper coating applied on a single side over a Kapton substrate. Kapton is the commercial designator for polyimide supplied by DuPont. Microclad is a key material in detonator manufacture and function. Detonators which utilize Microclad function when a large current applied through a thin bridge etched into the copper produces a plasma, accelerating a Kapton flyer into an explosive (PETN) pellet. The geometry and properties of the Microclad are a critical element of this process.

36 MATERIALS SCIENCE↗

A new equation of state for copper

A new copper equation of state is developed utilizing the available experimental data in addition to recent theoretical calculations. Semi-empirical models are fit to the data and the results are tabulated in the SNL SESAME format. Comparison to other copper EOS tables are given, along with recommendations of which tables provide the best accuracy.

36 MATERIALS SCIENCE↗

Life-Cycle Inventory of Critical Materials: Nickel, Copper, Titanium, and Rare-Earth Elements

The United States has developed a list of critical minerals/materials whose sustained and reliable supply is pivotal to the robust functioning of critical industrial sectors. A key concern with these minerals is their environmental effects as a function of their production location. This requires material and energy flow details for their processing steps. This report provides a life-cycle inventory (LCI) for producing four critical minerals and/or material systems (nickel, copper, titanium, and rare-earth elements) incorporated in the updated GREET® (Greenhouse gases, Regulated Emissions, and Energy use in Technologies) model. For these systems, we provide an LCI as a function of production location – domestic (within the United States) and international (geographies from where the US imports these minerals). Our LCI also considers variations in ore grades for nickel and copper. This report also provides an LCI for all intermediate materials used to produce these critical materials.

58 GEOSCIENCES↗

Thermal Conductivity of Electroplated Copper Onto Bulk Niobium at Cryogenic Temperatures

Superconducting radio-frequency (SRF) cavities made of high-purity bulk niobium are widely used in modern particle accelerators. The development of metallic outer coatings with high thermal conductivity would have a beneficial impact in terms of improved thermal stability, reduced material cost and for the development of conduction-cooled, cryogen-free SRF cavities. Several high-purity, fine-grain Nb samples have been coated with 2-4 mm thick copper by electroplating. Measurements of the thermal conductivity of the bimetallic Nb/Cu samples in the range 2 ? 7 K showed values of the order of 1 kW/(m K) at 4.3 K. Very good adhesion between copper and niobium was achieved by depositing a thin Cu layer by cold spray on the niobium, prior to electroplating the bulk Cu layer.

Dhakal, P.↗

Half-hard copper PTW model parameters for plastic deformation calibrated to strain rates from 10 −3 -10 7 /s

This document demonstrates a calibration of the Preston-Tonks-Wallace (PTW) model of plastic deformation that fairly accurately reproduces the flow stress of half-hard copper across strain rates varying by a factor of more than ten billion. The experiments included are quasistatic compression at low rates, Split Hopkinson Pressure Bar (SHPB) compression at intermediate rates, and arrested Richtmyer-Meshkov instability (RMI) growth at high strain rates. The temperatures vary from liquid nitrogen (77 K) to around 500 K. The largest true strains obtained are approximately 0.5. It would be interesting to compare the results to copper deformation data at higher pressures and higher strains.

36 MATERIALS SCIENCE↗

Direct Synthesis of Polyester from Biomass Derived 1,6-hexanediol using a Copper-Ceria Catalyst

Biomass derived polyesters are gaining attention due to their increased mechanical and thermal properties, and also because of their biodegradability. These polyesters are typically synthesized from polycondensation reactions between diols with dicarboxylic acids using catalysts. Other methods such as alcoholysis and acidolysis of low molecular weight esters and alcoholysis of acyl chlorides are also well known. Direct conversion of diol to ester without using dicarboxylic acid is not well known, and to our knowledge has not been reported over a solid catalyst. In this study, we report a direct synthesis of polyester from 1,6-hexanediol using a copper-ceria catalyst without using a dicarboxylic acid monomer. The copper-ceria catalysts were synthesized by incipient wetness impregnation method and characterized using X-ray photoelectron spectroscopy (XPS), X-ray diffraction analysis (XRD), Brunauer-Emmett-Teller (BET), and infrared spectroscopy (IR). Our initial studies show that 1,6-hexanediol can be converted to corresponding polyester at higher temperatures under atmospheric pressures of CO2 or N2. The reaction products were analyzed using nuclear magnetic resonance spectroscopy (NMR), gel permeation chromatography (GPC), high performance liquid chromatography (HPLC), and IR spectroscopy.

Biomass derived diols↗

Comparison of copper and aluminum as the thermal link material for conduction-cooled accelerator cavities

Cryocooler conduction-cooling has recently emerged as a new frontier for cryogenic cooling for superconducting radiofrequency (SRF) cavities. In this scheme, an SRF cavity is mechanically coupled to a closed-cycle cryocooler using linkages made of high thermal conductivity metals. In this note, we compare the thermal transport properties of high purity aluminum and high purity copper as applied to SRF cavity conduction cooling. We show that copper can enable faster cooldown than aluminum from room temperature to the base temperature near 4 K and behave equally well or better during steady state cavity operation near the base temperature.

36 MATERIALS SCIENCE↗

Sustainable production of extracellular polymeric substances and iron or copper complex from glutinous rice processing wastewater

Essential trace minerals play vital roles in maintaining human and animal health. However, an overdose of the existing inorganic trace minerals is prone to induce detrimental effects that outweigh positive benefits. In this study, an extracellular polymeric substances (EPS)-producing bacterium, identified as Bacillus licheniformis CCTCC M2020298, was isolated from marine using glutinous rice processing wastewater as enrichment medium. The EPS yield of Bacillus licheniformis CCTCC M2020298 could reach 8.62 g/L by using glutinous rice-processing wastewater containing medium. Furthermore, the potential of the EPS as a carrier for synthesizing EPS-iron (Fe) and EPS-copper (Cu) complex was explored. The results showed that the optimum condition for the synthesis EPS-Fe were the reaction temperature 70°C, pH 8.5–9.0 and mass ratio of EPS to trisodium citrate 2:1. The iron content of EPS-Fe reached 77.4 mg/g. Under the same condition, the copper content of EPS-Cu reached 90.7 mg/g. The elemental composition, functional groups and valence state of the mineral elements of EPS-Fe and EPS-Cu were well characterized. The EPS-Fe and EPS-Cu exhibited antioxidant activity in scavenging ·OH, DPPH and ·O 2− free radicals, thereby leading to reduced oxidative stress and apoptosis levels in human colonic epithelial cells in vitro . They also inhibited the proliferation of mouse hepatocellular carcinoma H22 and the growth of intestinal pathogens in vitro . This study provided an effective avenue for EPS production from glutinous rice processing wastewater and proved the potential of EPS-Fe and EPS-Cu complexes as a new-type comprehensive essential trace mineral supplement.

Chen, Zhen↗

Production of GMP-Compliant Clinical Amounts of Copper-61 Radiopharmaceuticals from Liquid Targets

PET imaging has gained significant momentum in the last few years, especially in the area of oncology, with an increasing focus on metal radioisotopes owing to their versatile chemistry and favourable physical properties. Copper-61 (t1/2 = 3.33 h, 61% β+, Emax = 1.216 MeV) provides unique advantages versus the current clinical standard (i.e., gallium-68) even though, until now, no clinical amounts of 61Cu-based radiopharmaceuticals, other than thiosemicarbazone-based molecules, have been produced. This study aimed to establish a routine production, using a standard medical cyclotron, for a series of widely used somatostatin analogues, currently labelled with gallium-68, that could benefit from the improved characteristics of copper-61. We describe two possible routes to produce the radiopharmaceutical precursor, either from natural zinc or enriched zinc-64 liquid targets and further synthesis of [61Cu]Cu-DOTA-NOC, [61Cu]Cu-DOTA-TOC and [61Cu]Cu-DOTA-TATE with a fully automated GMP-compliant process. The production from enriched targets leads to twice the amount of activity (3.28 ± 0.41 GBq vs. 1.84 ± 0.24 GBq at EOB) and higher radionuclidic purity (99.97% vs. 98.49% at EOB). Our results demonstrate, for the first time, that clinical doses of 61Cu-based radiopharmaceuticals can easily be obtained in centres with a typical biomedical cyclotron optimised to produce 18F-based radiopharmaceuticals.

Fonseca, Alexandra I. (ORCID:000000031924178X)↗

Adsorption of Malathion Onto Copper and Iron Surfaces Relevant to Water Infrastructure

This study investigated the adsorption of malathion to copper (Cu) and iron surfaces, including microspheres and pipe specimens similar to those in drinking water infrastructure. The solid phase concentration of malathion on the virgin and used Cu pipe specimens was generally between 0.2 and 1 mg/g. The adsorption capacity for Cu and iron microspheres was greater than those of the pipe specimens because of their higher surface‐area‐to‐volume ratios. Copper materials adsorbed more malathion than comparable iron materials. X‐ray photoelectron spectroscopy analysis of Cu and iron surfaces revealed peaks at 164 eV (S 2p) and 135 eV (P 2p), which suggests that malathion chemically bonded to the surfaces of the specimens. Metal oxides likely formed stable bonds with phosphorus through pi conjugation. These findings are the first to show that malathion can chemically adhere to Cu and iron pipe materials. This insight is critical for understanding the decontamination strategies needed for water networks.

Harper, Jr., Willie F.↗

Boron-deoxidized copper withstands brazing temperatures

Boron-deoxidized high-conductivity copper is used for fabrication of heat transfer components that are brazed in a hydrogen atmosphere. This copper has high strength and ductility at elevated temperatures and does not exhibit massive intergranular failure.

Schmidt, E. H.↗

High-strength braze joints between copper and steel

High-strength braze joints between copper and steel are produced by plating the faying surface of the copper with a layer of gold. This reduces porosity in the braze area and strengthens the resultant joint.

Kuhn, R. F.↗

Parallel-gap welding for joints between copper conductors and Kovar

Welding technique produces more reliable joints than soldering. Investigation used different sizes of copper conductors and component lead ribbons, corrosion protection platings, and melting points of metals being joined. Optimum combination is gold-plated component lead ribbons and solder-plated copper conductors.

Mc Daniel, G. E.↗

Influence of alloying elements on friction and wear of copper

The friction and wear characteristics were determined for copper binary alloys containing 10 atomic percent aluminum, silicon, indium, and tin. A ternary alloy containing 10 atomic percent aluminum and 5 atomic percent silicon was also examined. The effectiveness of each of the alloying elements aluminum and silicon were very effective in reducing friction. Silicon, however, also reduced wear appreciably. With lubrication, silicon, indium, and tin were all effective alloying elements in reducing friction and wear from values obtained for copper. Silicon was the most effective single element in reducing friction and wear in dry sliding and with lubrication.

Buckley, D. H.↗