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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,063 records · Page 59
All sourcesNASA NTRSDOE OSTI
NASA NTRS1950

Dependence of the elastic strain coefficient of copper on the pre-treatment

The effect of various pre-treatments on the elastic strain coefficient (alpha) (defined as the reciprocal of the modulus of elasticity E) (Epsilon) and on the mechanical hysteresis of copper has been investigated. Variables comprising the pre-treatments were pre-straining by stretching in a tensile testing machine and by drawing through a die, aging at room and elevated temperatures and annealing. The variation of the elastic strain coefficient with test stress was also investigated.

RODS - TENSION↗
DOE OSTI2016

Single-Crystal Copper Research

Presentation on the use of single-crystal copper to examine whether texture in polycrystalline metals is important, and when.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Self‐Trapped and Free Exciton Dynamics in Vacuum‐Deposited Cesium Copper Iodide Thin Films

Abstract Highly photoluminescent, lead‐free perovskites are of interest for displays and solid‐state light‐emitting devices. In this report, streak camera‐based time‐resolved emission and transient absorption spanning visible to deep‐ultraviolet (UV) wavelengths are utilized to study self‐trapped and free exciton dynamics in vacuum‐deposited cesium copper halide thin films of CsCu 2 I 3 and Cs 3 Cu 2 I 5 . Self‐trapped exciton emission of CsCu 2 I 3 exhibits more noticeable changes with time in the peak position and width than Cs 3 Cu 2 I 5 . UV‐to‐blue emission is detectable for both compositions, where free exciton emission is distinct for CsCu 2 I 3 . Transient absorption shows loss of ground‐state bleach signals at early time delays for both, and the bleach signal shifts toward higher energy as time delay increases, likely due to strains induced by the newly created self‐trapped excitons. Global analysis performed on the transient absorption results yields time constants in these materials that build an overall dynamic scheme. This work aids in building a complete picture regarding light emission in these promising materials.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Compact 3D Copper with Uniform Porous Structure Derived by Electrochemical Dealloying as Dendrite-Free Lithium Metal Anode Current Collector

Here, the development of lithium (Li) metal anodes Li metal batteries faces huge challenges such as uncontrolled Li dendrite growth and large volume change during Li plating/stripping, resulting in severe capacity decay and high safety hazards. A 3D porous copper (Cu) current collector as a host for Li deposition can effectively settle these problems. However, constructing a uniform and compact 3D porous Cu structure is still an enormous challenge. Herein, an electrochemical etching method for Cu–Zinc (Zn) alloy is reported to precisely engrave a 3D Cu structure with uniform, smooth, and compact porous network. Such a continuous structure endows 3D Cu excellent mechanical properties and high electrical conductivity. The uniform and smooth pores with a large internal surface area ensures well dispersed current density for homogeneous Li metal deposition and accommodation. A smooth and stable solid electrolyte interphase is formed and meanwhile Li dendrites and dead Li are effectively suppressed. The Li metal anode conceived 3D Cu current collector can stably cycle for 400 h under an Li plating/stripping capacity of 1 mA h cm –2 and a current density of 1 mA cm –2 . The Li@3D Cu||LiFePO 4 full cells present excellent cycling and rate performances. The electrochemical dealloying is a robust method to construct 3D Cu current collectors for dendrite–free Li metal anodes.

25 ENERGY STORAGE↗
DOE OSTI2017

Spectroscopic Evidence for a Monomeric Copper(I) Hydride and Crystallographic Characterization of a Monomeric Silver(I) Hydride

(1,3-bis[2,6-bis[di(4-tert-butylphenyl)methyl]-4-methylphenyl]imidazol-2-ylidene)CuOPh [(IPr**)CuOPh] reacts with poly(methylhydrosiloxane) as the hydride donor to afford the monomeric (IPr**)CuH complex, which was spectroscopically characterized. The latter is in equilibrium in solution with [(IPr**)CuH]2, the dimer being exclusively present in the solid state. In this work, these results support the hypothesis that copper hydride aggregates dissociate in solution. In contrast, addition of pinacolborane to [(IPr**)AgOPh] at –40 °C allows the isolation of the monomeric (IPr**)AgH complex, which was crystallographically characterized.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Copper‐Catalyzed Dehydrogenative Amidation of Light Alkanes

Abstract The functionalization of C−H bonds in light alkanes, particularly to form C−N bonds, remains a challenge. We report the dehydrogenative coupling of amides with C1–C4 hydrocarbons to form N‐alkyl amide products with tBuOOtBu as oxidant, and a copper complex of a phenanthroline‐type ligand as catalyst. The reactions occurred in good yields in benzene or supercritical carbon dioxide as solvents. This strategy allowed for the determination of the relative reactivity of these alkane C−H bonds toward this amination process and showed, in contrast to prior work with larger alkanes, that the reactivity correlated with bond dissociation energies.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2026

Dual Chemical Looping/Catalytic Process for Alkylation of Benzene With Ethane and Propane Yielding Ethylbenzene and Cumene Over Copper‐Containing Mordenite

Given the sustained demand for alkylated aromatics and the strained olefin market, there is an urgent need to develop efficient one‐step processes for the direct alkylation of aromatics using alkanes instead of olefins. Such technologies offer greater energy efficiency and sustainability by eliminating the need for separate, energy‐intensive alkane dehydrogenation steps. In this work, we report a dual chemical looping / catalytic process that couples alkane dehydrogenation with aromatic alkylation over a copper‐containing mordenite yielding up to 25% of alkylated aromatics with >97% selectivity per cycle. In situ MAS NMR and FTIR spectroscopies combined with DFT calculations showed that the alkylation of benzene with alkanes proceeds via a π‐bounded Cu(I)‐olefin intermediate, which subsequently interacts with benzene, catalyzed by Brønsted acid sites, leading to alkylated products that readily desorb from the active material into the gas phase. DFT calculations show that alkylation mediated solely by Cu(I) has prohibitively high barriers (>1.8 eV), whereas a bi‐functional pathway involving both Cu(I) and Brønsted acid sites can proceed with significantly lower barrier (0.8 eV) through a concerted C–C bond formation and proton transfer step.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2019

Photocatalytic Transformation of Amines to Imines by Meso-Porous Copper Sulfides

We have demonstrated a visible-light-driven catalytic process for amine to imine transformations, using a hydrothermal procedure based mesoporous copper sulfide material. The surface chemistry of this heterogeneously catalyzed process, which was further supported by computational calculations, was determined by the reaction kinetics, and reactive oxygen determination studies.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

A Straightforward Access to Cyclic (Alkyl)(amino)carbene Copper (I) Complexes

Here, the synthesis and characterization of cyclic (alkyl)(amino)carbene, bicyclic (alkyl)(amino)carbene and cyclic (amino)(barrelene)carbene copper (I) complexes is reported. These complexes are obtained via a scalable, versatile, green, and cost/user-friendly strategy.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

Copper Sensing in Alkaline Electrolyte Using Anodic Stripping Voltammetry by Means of a Lead Mediator

Anodic stripping voltammetry (ASV) is an analysis technique that permits the selective and quantitative analysis of metal ion species in solution. It is most commonly applied in neutral to acidic electrolyte largely due to inherent metal ion solubility. Bismuth (Bi) is a common film used for ASV due to its good sensitivity, overall stability and insensitivity to O2. ASV, utilizing a Bi film, along with cadmium (Cd) and lead (Pb) as the plating mediators, has recently been adapted to determine zinc (Zn) concentrations in highly alkaline environments (30 % NaOH or 35 % M KOH). Successful analysis of Zn in alkaline relies on the ability of the hydroxide to form soluble metal anion species, such as Bi(OH) 4 – and Zn(OH) 4 2– . Here, we look to extend this technique to detect and quantify copper (Cu) ions in these highly basic electrolytes. However, in general, the use of ASV to detect and quantify Cu ion concentrations is notoriously difficult as the Cu stripping peak potential overlays with that of Bi from the common Bi film electrode. Here, an ASV method for determining Cu concentration in alkaline solutions is developed utilizing Pb as a deposition mediator. As such, it was found that when analyzing Cu solutions in the presence of Pb, the stripping voltammetry curves present separate and defined Cu stripping peaks. Different analyzes were made to find the best stripping voltammetry performance conditions. As such, an accumulation time of 5 minutes, an accumulation potential of ≤–1.45 V vs. Hg/HgO, and a concentration of 35 wt% KOH were determined to be the conditions that presented the best ASV results. Utilizing these conditions, calibration curves in the presence of 5.0 ppm Pb showed the best linear stripping signal correlation with an r-squared value of 0.991 and a limit of detection (LOD) of 0.67 ppm. Lastly, these results give way to evaluating Cu concentrations using ASV in aqueous alkaline solutions.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Geochemistry of Potentially Toxic Trace Elements in Soils of Mining Area: A Case Study from Zangezur Copper and Molybdenum Combine, Armenia

Research was carried out to determine and asses the influence of mining industries on soil contamination with application of various pollution indices. For soil sampling 13 points were selected. Soil samples were analyzed for heavy metals by AAS. Eleven elements were determined and the greater quantities were generally observed in case of Mo and Cu. During the testing of soil pollution level pollution load index, degree of contamination (Cd) and geoaccumulation index were used. The correlation analysis revealed the strongest positive correlation between molybdenum and copper and that the high content of mentioned elements in soil was caused by mining industry. Assessment based on Cd showed that the 33.3% of A horizon soil samples referred to a very high degree of pollution. Obtained results will be useful for implementation of control measures of pollution and the remediation techniques.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2019

The Characterization of Dissolved Organic Matter in Reclaimed Water and Its Influence on Copper Toxicity

Water samples were collected from five phases of treatment in a municipal sewage reclaimed water plant and the DOM was characterized. Results indicated that the components and properties of DOM varied notably with sequential treatments, such as the fluorescence intensity, the molecular weight and the total acidity. Meanwhile the accumulation of Cu in Daphnia magna was analyzed following exposure to samples spiked with 50 µg/L copper, which were decreased by the presence of DOM in those water samples. Furthermore, this study found significant associations between fluorescence intensity and Cu accumulation (r{sup 2} = 0.778, p < 0.05), while increased total acidity was found to enhance the unit total organic carbon-Cu accumulation (r{sup 2} = 0.979, p < 0.01). This study provides useful information on the safety and effective management of reclaimed water as a potential water resource.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2018

Development of a New 4-Amino-1,8-Naphthalimide Derivative as a Fluorescent Probe for Monitoring the Divalent Copper Ion

This article presents the design and synthesis of a new variant of the 4-amino-1,8-naphthalimide fluorescent probe for monitoring the divalent copper ion, Cu{sup 2+}. The probe BRST, functionalized with two propionic carboxylic acid groups in its receptor moiety, demonstrated high selectivity and sensitivity for the detection of Cu{sup 2+} in competitive media of various metal ions in DMSO/HEPES buffer solution (1:1; pH 7.4), with a fluorescence quenching of 75.41%. Besides its good linearity with Cu{sup 2+}, the probe yielded commendable values of the association constant and the detection limit, 5.54 × 10{sup 5} M{sup –1} and 4.33 × 10{sup –9} M, respectively. The quenching of the fluorescence intensity of the sensor in the presence of Cu{sup 2+} ions is attributable to the strong paramagnetic nature of the Cu{sup 2+} ion. The fluorescence 'turn off' behavior of this simple and effective probe was successfully applied for the determination of Cu{sup 2+} levels in untreated water samples, with excellent recovery rates of 98–105.8%.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Removal of Iron and Copper Ions from the Liquid Phase by Modified Polymeric Membranes

Preparation of polymeric membranes based on cellulose acetate and modified by adding different amounts of a pore generating agent, which was polyvinylpyrrolidone (PVP), is presented and potential application of the membranes obtained for the removal of iron and copper ions from liquid phase is examined. Addition of various amounts of PVP has an impact on the physical (porosity, equilibrium water content and permeability) and chemical (content of the surface oxygen group, pH) properties of the membranes obtained. Filtration of iron and cupper solution leads to significant changes in the total content of surface oxygen groups, however the acidic oxygen groups remain dominant. With the content of PVP increasing within a certain range, the membrane permeability is improved. The membranes obtained show higher efficiency in removal of Fe{sup 3+} than Cu{sup 2+} ions, but with increasing content of PVP the efficiency in iron ions removal decreases and the total filtration resistance decreases after filtration of iron ions solutions.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Chitosan Functionalization with Amino Acids Yields to Higher Copper Ions Adsorption Capacity

Chitosan (Chi) beads were conjugated with three different amino acids [namely, glutamic acid (GLU), methionine (MET), and taurine (TAU)] aiming to increase the divalent copper ions uptake in aqueous media. Scanning Electron Microscopy evidenced the development of a large porous structure after amino acid functionalization, associated with the increase in a number of amino groups in the polymer backbone. X-Ray Photoelectron Spectroscopy and Fourier-Transform Infrared Spectra analyses were also employed to assess the conjugation of these three different amino acids in chitosan backbone. Adsorption experiments were conducted in a batch process, at 298 K, and kinetic data indicated a slightly better fitting for the pseudo-first-order model when compared to pseudo-second order. Intraparticle diffusion model suggested a three-step mechanism for Cu(II) adsorption kinetics, limited by the third step, the intraparticle diffusion. The isotherm data fitting to the traditional Langmuir and Freundlich models indicated a better fit for the former case. The amino acid conjugation resulted in the increase of the maximum adsorption capacity for Cu(II) from 1.30 mmol g{sup −1} prior to amino acid conjugation to values as high as 2.31 mmol g{sup −1}, 2.40 mmol g{sup −1} and 2.68 mmol g{sup −1} for Chi–TAU, Chi–GLU, and Chi–MET, respectively. These results are attributed to the introduction of additional amino groups and new carboxylate and amino acid residues into the chitosan backbone, which might also be explored for amino acid demanding applications.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2019

Twin-core sunflower-type photonic quasicrystal fibers incorporated gold, silver, and copper microwire: an ultrashort and broad bandwidth polarization splitter

Polarization splitters are beneficial in the field of passive optical devices which are principally used in the coherent optical communication systems. An ideal polarization splitter must possess an efficient coupling with significant optical bandwidth. Hence, we proposed a novel metal-filled polarization splitter based on twin-core sunflower-type photonic quasicrystal fiber (PQF). The characteristics of the proposed splitter such as coupling length, extinction ratio, and available optical bandwidth were investigated by using the commercially available software, COMSOL Multiphysics. These aforementioned characteristics were determined by optimizing the geometrical parameters of proposed PQF—first by using gold-filled PQF (AuPQF). With optimized geometrical parameters, the splitter achieved an ultra-short coupling length of 132 µm and an ultra-broad bandwidth of 301 nm (wavelength range 1.36–1.68 µm) with an extinction ratio below than − 20 dB which comprised E + S+C + L+U band. Secondly, a comparative study to use silver- and copper-filled PQF (AgPQF and CuPQF) was explored. Both AgPQF and CuPQF retained a short length with adequate bandwidth and a significant extinction ratio below than − 20 dB. The AgPQF has a coupling length of 137 µm with a bandwidth of 136 nm which operated at 1.44 µm wavelength, while CuPQF with 134 µm lengths with a bandwidth of 149 nm and operated at 1.50 µm wavelengths.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Structure Amorphization and Mechanical Properties of Nanolaminates of the Copper–Niobium System During High-Pressure Torsion

The results of investigation of structural transformations and mechanical behavior of nanolaminates are reported, which were manufactured by multiple rolling of alternating layers of copper and niobium, followed by high-pressure torsion in the Bridgeman chamber. A detailed analysis of structure alteration of the material under study is performed by the high-resolution TEM methods. The changes in the value of microhardness in three dimensions (3D) are investigated during variation of the degree of straining of nanolaminates in the course of their torsion. A phenomenon of structure amorphization and a sharp increase in strength characteristics are revealed.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2018

Structural Modification of Graphene on Copper Substrates Irradiated by Nanosecond High-Intensity Ion Beams

Interaction of a nanosecond high-intensity pulsed ion beam with thin graphene films on copper substrates is analyzed. Methods of Raman spectroscopy are used to investigate the degree of graphene degradation depending on the integral implanted dose. The role of the substrate in the structural degradation of graphene irradiated by charged particle beams is demonstrated using the software package SRIM, intended for modeling radiative defect cascades under irradiation by charged particle beams, and the data on radiation resistance of graphene available in the literature.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗