Direct synthesis of nitrogen-doped graphene on platinum wire as a new fiber coating method for the solid-phase microextraction of BXes in water samples: Comparison of headspace and cold-fiber headspace modes.

PubMed

Memarian, Elham; Hosseiny Davarani, Saied Saeed; Nojavan, Saeed; Movahed, Siyavash Kazemi

2016-09-07

In this work, a new solid-phase microextraction fiber was prepared based on nitrogen-doped graphene (N-doped G). Moreover, a new strategy was proposed to solve problems dealt in direct coating of N-doped G. For this purpose, first, Graphene oxide (GO) was coated on Pt wire by electrophoretic deposition method. Then, chemical reduction of coated GO to N-doped G was accomplished by hydrazine and NH3. The prepared fiber showed good mechanical and thermal stabilities. The obtained fiber was used in two different modes (conventional headspace solid-phase microextraction and cold-fiber headspace solid-phase microextraction (CF-HS-SPME)). Both modes were optimized and applied for the extraction of benzene and xylenes from different aqueous samples. All effective parameters including extraction time, salt content, stirring rate, and desorption time were optimized. The optimized CF-HS-SPME combined with GC-FID showed good limit of detections (LODs) (0.3-2.3 μg/L), limit of quantifications (LOQs) (1.0-7.0 μg/L) and linear ranges (1.0-5000 μg/L). The developed method was applied for the analysis of benzene and xylenes in rainwater and some wastewater samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Rapid in situ growth of oriented titanium-nickel oxide composite nanotubes arrays coated on a nitinol wire as a solid-phase microextraction fiber coupled to HPLC-UV.

PubMed

Zhen, Qi; Zhang, Min; Song, Wenlan; Wang, Huiju; Wang, Xuemei; Du, Xinzhen

2016-10-01

An oriented titanium-nickel oxide composite nanotubes coating was in situ grown on a nitinol wire by direct electrochemical anodization in ethylene glycol with ammonium fluoride and water for the first time. The morphology and composition of the resulting coating showed that the anodized nitinol wire provided a titania-rich coating. The titanium-nickel oxide composite nanotubes coated fiber was used for solid-phase microextraction of different aromatic compounds coupled to high-performance liquid chromatography with UV detection. The titanium-nickel oxide composite nanotubes coating exhibited high extraction capability, good selectivity, and rapid mass transfer for weakly polar UV filters. Thereafter the important parameters affecting extraction efficiency were investigated for solid-phase microextraction of UV filters. Under the optimized conditions, the calibration curves were linear in the range of 0.1-300 μg/L for target UV filters with limits of detection of 0.019-0.082 μg/L. The intraday and interday precision of the proposed method with the single fiber were 5.3-7.2 and 5.9-7.9%, respectively, and the fiber-to-fiber reproducibility ranged from 6.3 to 8.9% for four fibers fabricated in different batches. Finally, its applicability was evaluated by the extraction and determination of target UV filters in environmental water samples. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Laser Hot Wire Process: A Novel Process for Near-Net Shape Fabrication for High-Throughput Applications

NASA Astrophysics Data System (ADS)

Kottman, Michael; Zhang, Shenjia; McGuffin-Cawley, James; Denney, Paul; Narayanan, Badri K.

2015-03-01

The laser hot wire process has gained considerable interest for additive manufacturing applications, leveraging its high deposition rate, low dilution, thermal stability, and general metallurgical control including the ability to introduce and preserve desired meta-stable phases. Recent advancements in closed-loop process control and laser technology have increased productivity, process stability, and control of deposit metallurgy. The laser hot wire process has shown success in several applications: repairing and rejuvenating casting dies, depositing a variety of alloys including abrasion wear-resistant overlays with solid and tubular wires, and producing low-dilution (<5%) nickel alloy overlays for corrosion applications. The feasibility of fabricating titanium buildups is being assessed for aerospace applications.

Poly(ionic liquids)-coated stainless-steel wires packed into a polyether ether ketone tube for in-tube solid-phase microextraction.

PubMed

Feng, Juanjuan; Wang, Xiuqin; Tian, Yu; Luo, Chuannan; Sun, Min

2017-12-01

An in-tube solid-phase microextraction device was developed by packing poly(ionic liquids)-coated stainless-steel wires into a polyether ether ketone tube. An anion-exchange process was performed to enhance the extraction performance. Surface properties of poly(ionic liquids)-coated stainless-steel wires were characterized by scanning electron microscopy and energy dispersive X-ray spectrometry. The extraction device was connected to high-performance liquid chromatography equipment to build an online enrichment and analysis system. Ten polycyclic aromatic hydrocarbons were used as model analytes, and important conditions including extraction time and desorption time were optimized. The enrichment factors from 268 to 2497, linear range of 0.03-20 μg/L, detection limits of 0.010-0.020 μg/L, extraction and preparation repeatability with relative standard deviation less than 1.8 and 19%, respectively were given by the established online analysis method. It has been used to detect polycyclic aromatic hydrocarbons in environmental samples, with the relative recovery (5, 10 μg/L) in the range of 85.1-118.9%. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Millimeter Thin and Rubber-Like Solid-State Lighting Modules Fabricated Using Roll-to-Roll Fluidic Self-Assembly and Lamination.

PubMed

Park, Se-Chul; Biswas, Shantonu; Fang, Jun; Mozafari, Mahsa; Stauden, Thomas; Jacobs, Heiko O

2015-06-24

A millimeter thin rubber-like solid-state lighting module is reported. The fabrication of the lighting module incorporates assembly and electrical connection of light-emitting diodes (LEDs). The assembly is achieved using a roll-to-roll fluidic self-assembly. The LEDs are sandwiched in-between a stretchable top and bottom electrode to relieve the mechanical stress. The top contact is realized using a lamination technique that eliminates wire-bonding. © 2015 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Multidisciplinary analysis and design of printed wiring boards

NASA Astrophysics Data System (ADS)

Fulton, Robert E.; Hughes, Joseph L.; Scott, Waymond R., Jr.; Umeagukwu, Charles; Yeh, Chao-Pin

1991-04-01

Modern printed wiring board design depends on electronic prototyping using computer-based simulation and design tools. Existing electrical computer-aided design (ECAD) tools emphasize circuit connectivity with only rudimentary analysis capabilities. This paper describes a prototype integrated PWB design environment denoted Thermal Structural Electromagnetic Testability (TSET) being developed at Georgia Tech in collaboration with companies in the electronics industry. TSET provides design guidance based on enhanced electrical and mechanical CAD capabilities including electromagnetic modeling testability analysis thermal management and solid mechanics analysis. TSET development is based on a strong analytical and theoretical science base and incorporates an integrated information framework and a common database design based on a systematic structured methodology.

High efficiency proportional neutron detector with solid liner internal structures

DOEpatents

Kisner, Roger Allen; Holcomb, David Eugene; Brown, Gilbert M.

2014-08-05

A tube-style neutron detector, a panel-style neutron detector incorporating a plurality of tube-style neutron detectors, and a panel-style neutron detector including a plurality of anode wires are provided. A plurality of channels is provided in a neutron detector such that each channel has an inner surface of a coating layer including a neutron-absorbing material. A wire anode is provided at end of each channel so that electrons generated by a charged daughter particle generated by a neutron are collected to detect a neutron-matter interaction. Moderator units can be incorporated into a neutron detector to provide improved detection efficiencies and/or to determine neutron energy spectrum. Gas-based proportional response from the neutron detectors can be employed for special nuclear material (SNM) detection. This neutron detector can provide similar performance to .sup.3He-based detectors without requiring .sup.3He and without containing toxic, flammable, or high-pressure materials.

Phase III gross solids removal devices pilot study, 2002-2005.

DOT National Transportation Integrated Search

2005-12-01

The objective of the Phase III Gross Solids Removal Devices (GSRDs) Pilot study was to : evaluate the performance of non-proprietary devices that can capture gross solids and that can be : incorporated into existing highway drainage systems or implem...

Phase IV gross solids removal devices pilot study, 2004-2005.

DOT National Transportation Integrated Search

2005-12-01

The objective of the Phase IV Gross Solids Removal Device (GSRD) Pilot study was to evaluate : the performance of one non-proprietary device that can capture gross solids and that can be : incorporated into existing highway drainage systems or implem...

The upper critical field of filamentary Nb3Sn conductors

NASA Astrophysics Data System (ADS)

Godeke, A.; Jewell, M. C.; Fischer, C. M.; Squitieri, A. A.; Lee, P. J.; Larbalestier, D. C.

2005-05-01

We have examined the upper critical field of a large and representative set of present multifilamentary Nb3Sn wires and one bulk sample over a temperature range from 1.4 K up to the zero-field critical temperature. Since all present wires use a solid-state diffusion reaction to form the A15 layers, inhomogeneities with respect to Sn content are inevitable, in contrast to some previously studied homogeneous samples. Our study emphasizes the effects that these inevitable inhomogeneities have on the field-temperature phase boundary. The property inhomogeneities are extracted from field-dependent resistive transitions which we find broaden with increasing inhomogeneity. The upper 90%-99% of the transitions clearly separates alloyed and binary wires but a pure, Cu-free binary bulk sample also exhibits a zero-temperature critical field that is comparable to the ternary wires. The highest μ0Hc2 detected in the ternary wires are remarkably constant: The highest zero-temperature upper critical fields and zero-field critical temperatures fall within 29.5±0.3 and 17.8±0.3K, respectively, independent of the wire layout. The complete field-temperature phase boundary can be described very well with the relatively simple Maki-DeGennes model using a two-parameter fit, independent of composition, strain state, sample layout, or applied critical state criterion.

An etched stainless steel wire/ionic liquid-solid phase microextraction technique for the determination of alkylphenols in river water.

PubMed

Cui, Meiyu; Qiu, Jinxue; Li, Zhenghua; He, Miao; Jin, Mingshi; Kim, Jiman; Quinto, Maurizio; Li, Donghao

2015-01-01

In this study, a stainless steel wire/ionic liquid-solid phase microextraction technique was developed for the direct extraction of APs from water samples. Some parameters were optimised, such as selection of the substrate and ILs, extraction time, extraction temperature, stirring rate and sample pH, etc. The experimental data demonstrated that the etched stainless steel wire was a suitable substrate for IL-coated SPME. The coating was prepared by directly depositing the ILs onto the surface of the etched stainless steel wire, which exhibited a porous structure and a high surface area. The [C8MIM][PF6] IL exhibited maximum efficiency with an extraction time of 30 min, and the aqueous sample was maintained at 40 °C and adjusted to pH 2 under stirring conditions. The enrichment factor of the IL coating for the four APs ranged from 1382 to 4779, the detection limits (LOD, S/N=3) of the four APs ranged from 0.01 to 0.04 ng mL(-1) and the RSD values for purified water spiked with APs ranged from 4.0 to 11.8% (n=3). The calibration graphs were linear in the concentration range from 0.5 to 200 ng mL(-1) (R(2)>0.9569). The optimised method was successfully applied for the analysis of real water samples, and the method was suitable for the extraction of APs from water samples. Copyright © 2014 Elsevier B.V. All rights reserved.

Involvement of prostaglandins and histamine in nickel wire-induced acute inflammation in mice.

PubMed

Hirasawa, Noriyasu; Goi, Yoshiaki; Tanaka, Rina; Ishihara, Kenji; Ohtsu, Hiroshi; Ohuchi, Kazuo

2010-06-15

The irritancy of Nickel (Ni) ions has been well documented clinically. However, the chemical mediators involved in the acute inflammation induced by solid Ni are not fully understood. We used the Ni wire-implantation model in mice and examined roles of prostaglandins and histamine in plasma leakage in the acute phase. The subcutaneous implantation of a Ni wire into the back of mice induced plasma leakage from 8 to 24 h and tissue necrosis around the wire at 3 days, whereas the implantation of an aluminum wire induced no such inflammatory responses. An increase in the mRNA for cyclooxygenase (COX)-2 and HDC in cells around the Ni wire was detected 4 h after the implantation. The leakage of plasma at 8 h was inhibited by indomethacin in a dose-dependent manner. Dexamethasone and the p38 MAP kinase inhibitor SB203580 also inhibited the exudation of plasma consistent with the inhibition of the expression of COX-2 mRNA. Furthermore, plasma leakage was partially but siginificantly reduced in histamine H1 receptor knockout mice and histidine decarboxylase (HDC) knockout mice but not in H2 receptor knockout mice. These results suggested that the Ni ions released from the wire induced the expression of COX-2 and HDC, resulting in an increase in vascular permeability during the acute phase of inflammation. (c) 2009 Wiley Periodicals, Inc.

Exploration of new superconductors and functional materials, and fabrication of superconducting tapes and wires of iron pnictides.

PubMed

Hosono, Hideo; Tanabe, Keiichi; Takayama-Muromachi, Eiji; Kageyama, Hiroshi; Yamanaka, Shoji; Kumakura, Hiroaki; Nohara, Minoru; Hiramatsu, Hidenori; Fujitsu, Satoru

2015-06-01

This review shows the highlights of a 4-year-long research project supported by the Japanese Government to explore new superconducting materials and relevant functional materials. The project found several tens of new superconductors by examining ∼1000 materials, each of which was chosen by Japanese experts with a background in solid state chemistry. This review summarizes the major achievements of the project in newly found superconducting materials, and the fabrication wires and tapes of iron-based superconductors; it incorporates a list of ∼700 unsuccessful materials examined for superconductivity in the project. In addition, described are new functional materials and functionalities discovered during the project.

Exploration of new superconductors and functional materials, and fabrication of superconducting tapes and wires of iron pnictides

PubMed Central

Hosono, Hideo; Tanabe, Keiichi; Takayama-Muromachi, Eiji; Kageyama, Hiroshi; Yamanaka, Shoji; Kumakura, Hiroaki; Nohara, Minoru; Hiramatsu, Hidenori; Fujitsu, Satoru

2015-01-01

This review shows the highlights of a 4-year-long research project supported by the Japanese Government to explore new superconducting materials and relevant functional materials. The project found several tens of new superconductors by examining ∼1000 materials, each of which was chosen by Japanese experts with a background in solid state chemistry. This review summarizes the major achievements of the project in newly found superconducting materials, and the fabrication wires and tapes of iron-based superconductors; it incorporates a list of ∼700 unsuccessful materials examined for superconductivity in the project. In addition, described are new functional materials and functionalities discovered during the project. PMID:27877784

Non-contact current and voltage sensor having detachable housing incorporating multiple ferrite cylinder portions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carpenter, Gary D.; El-Essawy, Wael; Ferreira, Alexandre Peixoto

2016-04-26

A detachable current and voltage sensor provides an isolated and convenient device to measure current passing through a conductor such as an AC branch circuit wire, as well as providing an indication of an electrostatic potential on the wire, which can be used to indicate the phase of the voltage on the wire, and optionally a magnitude of the voltage. The device includes a housing formed from two portions that mechanically close around the wire and that contain the current and voltage sensors. The current sensor is a ferrite cylinder formed from at least three portions that form the cylindermore » when the sensor is closed around the wire with a hall effect sensor disposed in a gap between two of the ferrite portions along the circumference to measure current. A capacitive plate or wire is disposed adjacent to, or within, the ferrite cylinder to provide the indication of the voltage.« less

Observations of the freeze/thaw performance of lithium fluoride by motion picture photography

NASA Technical Reports Server (NTRS)

Jaworske, D. A.; Perry, W. D.

1991-01-01

To gain direct observation of the molten salt phase change, a novel containerless technique was developed where the high surface tension of lithium fluoride was used to suspend a bead of the molten salt inside a specially designed wire cage. By varying the current passing through the wire, the cage also served as a variable heat source. In this way, the freeze/thaw performance of the lithium fluoride could be photographed by motion picture photography without the influence of container walls. The motion picture photography of the lithium fluoride sample revealed several zones during the phase change, a solid zone and a liquid zone, as expected, and a slush zone that was predicted by thermal analysis modeling.

Solid state phase change materials for thermal energy storage in passive solar heated buildings

NASA Astrophysics Data System (ADS)

Benson, D. K.; Christensen, C.

1983-11-01

A set of solid state phase change materials was evaluated for possible use in passive solar thermal energy storage systems. The most promising materials are organic solid solutions of pentaerythritol, pentaglycerine and neopentyl glycol. Solid solution mixtures of these compounds can be tailored so that they exhibit solid-to-solid phase transformations at any desired temperature within the range from less than 25 deg to 188 deg. Thermophysical properties such as thermal conductivity, density and volumetric expansion were measured. Computer simulations were used to predict the performance of various Trombe wall designs incorporating solid state phase change materials. Optimum performance was found to be sensitive to the choice of phase change temperatures and to the thermal conductivity of the phase change material. A molecular mechanism of the solid state phase transition is proposed and supported by infrared spectroscopic evidence.

A sol-gel based solid phase microextraction fiber for the analysis of aliphatic alcohols in apple juices.

PubMed

Farhadi, Khalil; Maleki, Ramin; Tahmasebi, Raheleh

2010-01-01

A new fiber based on titania-chitin sol-gel coated on a silver wire for the headspace solid phase microextraction of aliphatic alcohols from apple juice samples was developed. The influences of fiber coating composition and microextraction conditions (extraction temperature, extraction time, and ionic strength of the sample matrix) on the fiber performance were investigated. Also, the influence of temperature and time on desorption of analytes from fiber were studied. Under the optimized conditions, a porous fiber with a high extraction capacity and good thermal stability (up to 250 degrees C) was obtained. The proposed headspace solid-phase microextraction-GC method was successfully used for the analysis of aliphatic alcohols in apple juice and concentrate samples. The recovery values were from 92.8 to 98.6%. The RSD (n=5) for all analytes were below 7.8%.

Scientific support for an orbiter middeck experiment on solid surface combustion

NASA Technical Reports Server (NTRS)

Altenkirch, Robert A.; Vedha-Nayagam, M.; Srikantaiah, Nataraj

1988-01-01

The objective is to determine the mechanism of gas-phase flame spread over solid fuel surfaces in the absence of any buoyancy or externally imposed gas-phase flow. Such understanding can be used to improve the fire safety aspects of space travel by providing information that will allow judicious selections of spacecraft materials and environments to be made. The planned experiment consists of measuring the flame spread rate over thermally thin and thermally thick fuels in a closed container in the low-gravity environment of the Space Shuttle. Measurements consist of flame spread rate and shape obtained from two views of the process as recorded on movie film and surface and gas-phase temperatures obtained from fine-wire thermocouples. The temperature measurements along with appropriate modeling provide information about the gas-to-solid heat flux. Environmental parameters to be varied are the oxygen concentration and pressure.

Numerical simulation of fiber and wire array Z-pinches with Trac-II

NASA Astrophysics Data System (ADS)

Reisman, David Barton

Trac-II is a two dimensional axisymmetric resistive MHD code. It simulates all three spatial components (r, z, φ) of the magnetic field and fluid velocity vectors, and the plasma is treated as a single fluid with two temperatures (Te,Ti). In addition, it can optionally include a self-consistent external circuit. Recent modifications to the code include the addition of the 3-T radiation model, a 4-phase (solid- liquid-vapor-plasma) equation of state model (QEOS), a 4- phase electrical/thermal conductivity model, and an implicit solution of poloidal (Bz,Br) magnetic field diffusion. These changes permit a detailed study of fiber and wire array Z-pinches. Specifically, Trac-II is used to study the wire array Z-pinch at the PBFA-Z pulse power generator at Sandia National Laboratory. First, in 1-D we examine the behavior of a single wire in the Z-pinch. Then, using these results as initial radial conditions in 2-D, we investigate the dynamics of wire array configurations in the r-z and r-θ plane. In the r- z plane we examine the growth of the m = 0 or ``sausage'' instability in single wires within the array. In the r-θ plane we examine the merging behavior between neighboring wires. Special emphasis is placed on trying to explain how instability growth affects the performance of the Z-pinch. Lastly, we introduce Trac-III, a 3-D MHD code, and illustrate the m = 1 or ``kink'' instability. We also discuss how Trac-III can be modified to simulate the wire array Z-pinch.

Digital Systems Validation Handbook. Volume 2

DTIC Science & Technology

1989-02-01

power. 2. A grid of wires, solid sheet, or foil. 3. A wire from circuit to grounding block or case. 4. A wire from circuit to structure. 5. Shield...RETURN. (11) 1. Structure, for power, fault, and "discrete" circuits. 2. A grid of wires, solid sheet, or foil. 3. A wire from circuit load back to...TV (14) Television TWTD (13) Thin Wire Time Domain TX (5) Transmit U.K. (13,141 United Kingdom U.S. (14) United States UART (15) Universal Asynchronous

Aluminum-catalyzed silicon nanowires: Growth methods, properties, and applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hainey, Mel F.; Redwing, Joan M.

Metal-mediated vapor-liquid-solid (VLS) growth is a promising approach for the fabrication of silicon nanowires, although residual metal incorporation into the nanowires during growth can adversely impact electronic properties particularly when metals such as gold and copper are utilized. Aluminum, which acts as a shallow acceptor in silicon, is therefore of significant interest for the growth of p-type silicon nanowires but has presented challenges due to its propensity for oxidation. This paper summarizes the key aspects of aluminum-catalyzed nanowire growth along with wire properties and device results. In the first section, aluminum-catalyzed nanowire growth is discussed with a specific emphasis onmore » methods to mitigate aluminum oxide formation. Next, the influence of growth parameters such as growth temperature, precursor partial pressure, and hydrogen partial pressure on nanowire morphology is discussed, followed by a brief review of the growth of templated and patterned arrays of nanowires. Aluminum incorporation into the nanowires is then discussed in detail, including measurements of the aluminum concentration within wires using atom probe tomography and assessment of electrical properties by four point resistance measurements. Finally, the use of aluminum-catalyzed VLS growth for device fabrication is reviewed including results on single-wire radial p-n junction solar cells and planar solar cells fabricated with nanowire/nanopyramid texturing.« less

Chemically and compositionally modified solid solution disordered multiphase nickel hydroxide positive electrode for alkaline rechargeable electrochemical cells

DOEpatents

Ovshinsky, Stanford R.; Corrigan, Dennis; Venkatesan, Srini; Young, Rosa; Fierro, Christian; Fetcenko, Michael A.

1994-01-01

A high capacity, long cycle life positive electrode for use in an alkaline rechargeable electrochemical cell comprising: a solid solution nickel hydroxide material having a multiphase structure that comprises at least one polycrystalline .gamma.-phase including a polycrystalline .gamma.-phase unit cell comprising spacedly disposed plates with at least one chemical modifier incorporated around the plates, the plates having a range of stable intersheet distances corresponding to a 2.sup.+ oxidation state and a 3.5.sup.+, or greater, oxidation state; and at least one compositional modifier incorporated into the solid solution nickel hydroxide material to promote the multiphase structure.

Dipolar recoupling in solid state NMR by phase alternating pulse sequences

PubMed Central

Lin, J.; Bayro, M.; Griffin, R. G.; Khaneja, N.

2009-01-01

We describe some new developments in the methodology of making heteronuclear and homonuclear recoupling experiments in solid state NMR insensitive to rf-inhomogeneity by phase alternating the irradiation on the spin system every rotor period. By incorporating delays of half rotor periods in the pulse sequences, these phase alternating experiments can be made γ encoded. The proposed methodology is conceptually different from the standard methods of making recoupling experiments robust by the use of ramps and adiabatic pulses in the recoupling periods. We show how the concept of phase alternation can be incorporated in the design of homonuclear recoupling experiments that are both insensitive to chemical-shift dispersion and rf-inhomogeneity. PMID:19157931

Investigating Li 2NiO 2–Li 2CuO 2 Solid Solutions as High-Capacity Cathode Materials for Li-Ion Batteries

DOE PAGES

Xu, Jing; Renfrew, Sara; Marcus, Matthew A.; ...

2017-05-11

Li 2Ni 1–xCu xO 2 solid solutions were prepared by a solid-state method to study the correlation between composition and electrochemical performance. Cu incorporation improved the phase purity of Li 2Ni 1–xCu xO 2 with orthorhombic Immm structure, resulting in enhanced capacity. However, the electrochemical profiles suggested Cu incorporation did not prevent irreversible phase transformation during the electrochemical process, instead, it likely influenced the phase transformation upon lithium removal. By combining ex situ X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS), and differential electrochemical mass spectrometry (DEMS) measurements, this study elucidates the relevant phase transformation (e.g., crystal structure, local environment, andmore » charge compensation) and participation of electrons from lattice oxygen during the first cycle in these complex oxides.« less

Multilayer graphene on insulator formed by Co-induced layer exchange

NASA Astrophysics Data System (ADS)

Murata, Hiromasa; Toko, Kaoru; Suemasu, Takashi

2017-05-01

The direct synthesis of multilayer graphene (MLG) on arbitrary substrates is essential for incorporating carbon wirings and heat spreaders into electronic devices. Here, we applied the metal-induced layer exchange (MILE) technique, developed for group-IV semiconductors, to a sputtered amorphous carbon (a-C) thin film using Co as a catalyst. MLG was formed on a SiO2 substrate at 800 °C for 10 min; however, it disappeared during wet etching for removing Co. This behavior was attributed to the small contact area between MLG and SiO2 caused by the deformation of the Co layer during annealing. By preparing the Co layer at 200 °C, its thermal stability was improved, resulting in the synthesis of MLG on the substrate through MILE. Raman measurements indicated good crystal quality of the MLG compared with that obtained by conventional metal-induced solid-phase crystallization. MILE was thus proven to be useful not only for group-IV semiconductors but also for carbon materials on insulators.

A Study on Phase Changes of Heterogeneous Composite Materials

NASA Astrophysics Data System (ADS)

Hirasawa, Yoshio; Saito, Akio; Takegoshi, Eisyun

In this study, a phase change process in heterogeneous composite materials which consist of water and coiled copper wires as conductive solid is investigated by four kinds of typical calculation models : 1) model-1 in which the effective thermal conductivity of the composite material is used, 2) model-2 in which a fin metal acts for many conductive solids, 3) model-3 in which the effective thermal conductivities between nodes are estimated and three-dimensional calculation is performed, 4) model-4 proposed by authors in the previous paper in which effective thermal conductivity is not needed. Consequently, model-1 showed the phase change rate considerably lower than the experimental results. Model-2 gave the larger amount of the phase change rate. Model-3 agreed well with the experiment in the case of small coil diameter and relatively large Vd. Model-4 showed a very well agreement with the experiment in the range of this study.

Twin-Axial Wire Antenna

DTIC Science & Technology

2015-08-06

12 and 14 can be of differing gauges and can be either stranded or solid. In a prototype, both conductors were made from #22 solid copper wire ...08-2015 Publication Twin-Axial Wire Antenna David A. Tonn Naval Under Warfare Center Division, Newport 1176 Howell St., Code 00L, Bldg 102T...Approved for Public Release Distribution is unlimited Attorney Docket No. 300030 1 of 10 TWIN-AXIAL WIRE ANTENNA STATEMENT OF GOVERNMENT INTEREST

Laser Annealing on the Surface Treatment of Thin Super Elastic NiTi Wire

NASA Astrophysics Data System (ADS)

Samal, S.; Heller, L.; Brajer, J.; Tyc, O.; Kadrevek, L.; Sittner, P.

2018-05-01

Here the aim of this research is annealing the surface of NiTi wire for shape memory alloy, super-elastic wire by solid state laser beam. The laser surface treatment was carried out on the NiTi wire locally with fast, selective, surface heat treatment that enables precisely tune the localized material properties without any precipitation. Both as drawn (hard) and straight annealing NiTi wire were considered for laser annealing with input power 3 W, with precisely focusing the laser beam height 14.3 % of the Z-axis with a spot size of 1 mm. However, straight annealing wire is more interest due to its low temperature shape setting behavior and used by companies for stent materials. The variable parameter such as speed of the laser scanning and tensile stress on the NiTi wire were optimized to observe the effect of laser response on the sample. Superelastic, straight annealed NiTi wires (d: 0.10 mm) were held prestrained at the end of the superelastic plateau (ε: 5 ∼6.5 %) above the superelastic region by a tensile machine ( Mitter: miniature testing rig) at room temperature (RT). Simultaneously, the hardness of the wires along the cross-section was performed by nano-indentation (NI) method. The hardness of the NiTi wire corresponds to phase changes were correlated with NI test. The laser induced NiTi wire shows better fatigue performance with improved 6500 cycles.

Preparation of a polymeric ionic liquid-coated solid-phase microextraction fiber by surface radical chain-transfer polymerization with stainless steel wire as support.

PubMed

Feng, Juanjuan; Sun, Min; Xu, Lili; Li, Jubai; Liu, Xia; Jiang, Shengxiang

2011-10-28

Polymeric 1-vinyl-3-octylimidazolium hexafluorophosphate was synthesized in situ on stainless steel wire by surface radical chain-transfer polymerization and used as sensitive coatings in solid-phase microextraction. The outer surface of the stainless steel wire was firstly coated with microstructured silver layer via silver mirror reaction and then functionalized with self-assembled monolayers of 1,8-octanedithiol, which acted as chain transfer agent in the polymerization. Coupled to gas chromatography, extraction performance of the fiber was studied with both headspace and direct-immersion modes using benzene, toluene, ethylbenzene and xylenes (BTEX), phenols and polycyclic aromatic hydrocarbon (PAHs) as model analytes. In combination with the microstructured silver layer, the PIL-coated fiber exhibited high extraction efficiency. Linear ranges for BTEX with headspace mode were in the range of 0.2-1000 μg L(-1) for benzene, and 0.1-1000 μg L(-1) for toluene, ethylbenzene and xylenes. Limits of detection (LODs) were from 0.02 to 0.05 μg L(-1). Wide linear ranges of direct-immersion mode for the extraction of several phenols and PAHs were also obtained with correlation coefficients (R) from 0.9943 to 0.9997. The proposed fiber showed good durability with long lifetime. RSDs of 56 times extraction were still in an acceptable range, from 8.85 to 22.8%. Copyright © 2011 Elsevier B.V. All rights reserved.

Sol-gel approach for fabrication of coated anodized titanium wire for solid-phase microextraction: highly efficient adsorbents for enrichment of trace polar analytes.

PubMed

Jia, Jing; Xu, Lili; Wang, Shuai; Wang, Licheng; Liu, Xia

2014-05-01

Nanotubular titania film was prepared in situ on titanium wire and was used as the fiber substrate for solid-phase microextraction (SPME) because of its high surface-to-volume ratio, easy preparation, and mechanical stability. Three different functional coatings, β-cyclodextrin (β-CD), β-cyclodextrin-co-poly(ethylenepropylene glycol) (β-CD/PEG), and polyethylene glycol (PEG)-based sorbents were chemically bonded to the nanostructured wire surface via sol-gel technology to further enhance the absorbing capability and extraction selectivity. Coupled to gas chromatography-flame ionic detection (GC-FID), the prepared SPME fibers were investigated using diverse compounds. The results indicated that the fibers showed good mechanical strength, excellent thermal stability, and wonderful capacity and selectivity to polar compounds, including polar aromatic compounds, alcohols, and ketones. Combining the superior hydrophilic property of a bonded functional molecule and the highly porous structure of a fiber coating, the prepared PEG-coated SPME fiber showed much higher adsorption affinity to ephedrine and methylephedrine than β-CD and β-CD/PEG fibers. The as-established PEG-coated SPME-GC analytical method provided excellent sensitivity (LODs, 0.004 and 0.001 ng mL(-1) for ephedrine and methylephedrine, respectively) and better linear range (0.01-2 000 μg L(-1)). In addition, it has surprising repeatability and reproducibility. Finally, the present approach was used to analyze ephedrine and methylephedrine from real urine samples, and reliable results were obtained.

Silicon carbide nanomaterial as a coating for solid-phase microextraction.

PubMed

Tian, Yu; Feng, Juanjuan; Wang, Xiuqin; Sun, Min; Luo, Chuannan

2018-01-26

Silicon carbide has excellent properties, such as corrosion resistance, high strength, oxidation resistance, high temperature, and so on. Based on these properties, silicon carbide was coated on stainless-steel wire and used as a solid-phase microextraction coating, and polycyclic aromatic hydrocarbons were employed as model analytes. Using gas chromatography, some important factors that affect the extraction efficiency were optimized one by one, and an analytical method was established. The analytical method showed wide linear ranges (0.1-30, 0.03-30, and 0.01-30 μg/L) with satisfactory correlation coefficients (0.9922-0.9966) and low detection limits (0.003-0.03 μg/L). To investigate the practical application of the method, rainwater and cigarette ash aqueous solution were collected as real samples for extraction and detection. The results indicate that silicon carbide has excellent application in the field of solid-phase microextraction. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Characterization of the aroma profile of novel Brazilian wines by solid-phase microextraction using polymeric ionic liquid sorbent coatings.

PubMed

Crucello, Juliana; Miron, Luiz F O; Ferreira, Victor H C; Nan, He; Marques, Marcia O M; Ritschel, Patricia S; Zanus, Mauro C; Anderson, Jared L; Poppi, Ronei J; Hantao, Leandro W

2018-05-28

In this study, a series of polymeric ionic liquid (PIL) sorbent coatings is evaluated for the extraction of polar volatile organic compounds (VOCs) from Brazilian wines using headspace solid-phase microextraction (HS-SPME), including samples from 'Isabella' and 'BRS Magna' cultivars-the latter was recently introduced by the Brazilian Agricultural Research Corporation - National Grape & Wine Research Center. The structurally tuned SPME coatings were compared to the commercial SPME phases, namely poly(acrylate) (PA) and divinylbenzene/carboxen/poly(dimethylsiloxane) (DVB/CAR/PDMS). The separation, detection and identification of the aroma profiles were obtained using comprehensive two-dimensional gas chromatography mass spectrometry (GC×GC-MS). The best performing PIL-based SPME fiber, namely 1-hexadecyl-3-vinylimidazolium bis[(trifluoromethyl)sulfonyl]imide with 1,12-di(3-vinylimidazolium)dodecane dibis[(trifluoromethyl)sulfonyl]imide incorporated cross-linker supported on an elastic nitinol wire, exhibited superior performance to DVB/CAR/PDMS regarding the average number of extracted peaks and extracted more polar analytes providing additional insight into the aroma profile of 'BRS Magna' wines. Four batches of wine were evaluated, namely 'Isabella' and 'BRS Magna' vintages 2015 and 2016, using highly selective PIL-based SPME coatings and enabled the detection of 350+ peaks. Furthermore, this is the first report evaluating the aroma of 'BRS Magna' wines. A hybrid approach that combined pixel-based Fisher ratio and peak table-based data comparison was used for data handling. This proof-of-concept experiment provided reliable and statistically valid distinction of wines that may guide regulation agencies to create high sample throughput protocols to screen wines exported by Brazilian vintners. Graphical abstract Highly selective extraction of wine aroma using polymeric ionic liquid.

A new test method for the assessment of the arc tracking properties of wire insulation in air, oxygen enriched atmospheres and vacuum

NASA Technical Reports Server (NTRS)

Koenig, Dieter

1994-01-01

Development of a new test method suitable for the assessment of the resistance of aerospace cables to arc tracking for different specific environmental and network conditions of spacecraft is given in view-graph format. The equipment can be easily adapted for tests at different realistic electrical network conditions incorporating circuit protection and the test system works equally well whatever the test atmosphere. Test results confirm that pure Kapton insulated wire has bad arcing characteristics and ETFE insulated wire is considerably better in air. For certain wires, arc tracking effects are increased at higher oxygen concentrations and significantly increased under vacuum. All tests on different cable insulation materials and in different environments, including enriched oxygen atmospheres, resulted in a more or less rapid extinguishing of all high temperature effects at the beginning of the post-test phase. In no case was a self-maintained fire initiated by the arc.

Prosthetic leg powered by MR brake and SMA wires

NASA Astrophysics Data System (ADS)

Nguyen, The; Munguia, Vicente; Calderon, Jose

2014-04-01

Current knee designs for prosthetic legs rely on electric motors for both moving and stationary states. The electric motors draw an especially high level of current to sustain a fixed position. The advantage of using magnetorheological (MR) fluid is that it requires less current and can have a variable braking torque. Besides, the proposed prosthetic leg is actuated by NiTinol wire, a popular shape memory alloy (SMA). The incorporation of NiTinol gives the leg more realistic weight distribution with appropriate arrangement of the batteries and wires. The prosthesis in this research was designed with MR brake as stopping component and SMA wire network as actuating component at the knee. The MR brake was designed with novel non-circular shape for the rotor that improved the braking torque while minimizing the power consumption. The design also helped simplify the control of braking process. The SMA wire network was design so that the knee motion was actively rotated in both directions. The SMA wires were arranged and played very similar role as the leg's muscles. The study started with the overall solid design of the knee including both MR and SMA parts. Theoretical models were derived and programmed in Simulink for both components. The simulation was capable of predicting the power required for moving the leg or hold it in a fixed position for a certain amount of time. Subsequently, the design was prototyped and tested to validate the theoretical prediction. The theoretical models were updated accordingly to correlate with the experimental data.

Wire-Active Microrheology to Differentiate Viscoelastic Liquids from Soft Solids.

PubMed

Loosli, Frédéric; Najm, Matthieu; Chan, Raymond; Oikonomou, Evdokia; Grados, Arnaud; Receveur, Mathieu; Berret, Jean-François

2016-12-15

Viscoelastic liquids are characterized by a finite static viscosity and a yield stress of zero, whereas soft solids have an infinite viscosity and a non-zero yield stress. The rheological nature of viscoelastic materials has long been a challenge and is still a matter of debate. Here, we provide for the first time the constitutive equations of linear viscoelasticity for magnetic wires in yield-stress materials, together with experimental measurements by using magnetic rotational spectroscopy (MRS). In MRS, the wires were subjected to a rotational magnetic field as a function of frequency and the motion of the wire was monitored by using time-lapse microscopy. The studied soft solids were aqueous dispersions of gel-forming polysaccharide (gellan gum) at concentrations above the gelification point. It was found that soft solids exhibited a clear and distinctive signature compared with viscous and viscoelastic liquids. In particular, the average wire rotation velocity equaled zero over a broad frequency range. We also showed that the MRS technique is quantitative. The equilibrium elastic modulus was retrieved from the wire oscillation amplitudes, and agrees with polymer-dynamics theory. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Zn-Li alloy after extrusion and drawing: Structural, mechanical characterization, and biodegradation in abdominal aorta of rat.

PubMed

Zhao, Shan; Seitz, Jan-M; Eifler, Rainer; Maier, Hans J; Guillory, Roger J; Earley, Elisha J; Drelich, Adam; Goldman, Jeremy; Drelich, Jaroslaw W

2017-07-01

Zinc shows great promise as a bio-degradable metal. Our early in vivo investigations implanting pure zinc wires into the abdominal aorta of Sprague-Dawley rats revealed that metallic zinc does not promote restenotic responses and may suppress the activities of inflammatory and smooth muscle cells. However, the low tensile strength of zinc remains a major concern. A cast billet of the Zn-Li alloy was produced in a vacuum induction caster under argon atmosphere, followed by a wire drawing process. Two phases of the binary alloy identified by x-ray diffraction include the zinc phase and intermetallic LiZn 4 phase. Mechanical testing proved that incorporating 0.1wt% of Li into Zn increased its ultimate tensile strength from 116±13MPa (pure Zn) to 274±61MPa while the ductility was held at 17±7%. Implantation of 10mm Zn-Li wire segments into abdominal aorta of rats revealed an excellent biocompatibility of this material in the arterial environment. The biodegradation rate for Zn-Li was found to be about 0.008mm/yr and 0.045mm/yr at 2 and 12months, respectively. Copyright © 2017 Elsevier B.V. All rights reserved.

Examination of rapid phase change in copper wires to improve material models and understanding of burst

NASA Astrophysics Data System (ADS)

Olles, Joseph; Garasi, Christopher; Ball, J. Patrick

2017-11-01

Electrically-pulsed wires undergo multiple phase changes including a postulated metastable phase resulting in explosive wire growth. Simulations using the MHD approximation attempt to account for the governing physics, but lack the material properties (equations-of-state and electrical conductivity) to accurately predict the phase evolution of the exploding (bursting) wire. To explore the dynamics of an exploding copper wire (in water), we employ a digital micro-Schlieren streak photography technique. This imaging quantifies wire expansion and shock waves emitted from the wire during phase changes. Using differential voltage probes, a Rogowski coil, and timing fiducials, the phase change of the wire is aligned with electrical power and energy deposition. Time-correlated electrical diagnostics and imaging allow for detailed validation of MHD simulations, comparing observed phases with phase change details found in the material property descriptions. In addition to streak imaging, a long exposure image is taken to capture axial striations along the length of the wire. These images are used to compare with results from 3D MHD simulations which propose that these perturbations impact the rate of wire expansion and temporal change in phases. If successful, the experimental data will identify areas for improvement in the material property models, and modeling results will provide insight into the details of phase change in the wire with correlation to variations in the electrical signals.

Investigation of fragrance stability used in the formulation of cosmetic and hygienic products using headspace solid-phase microextraction by nanostructured materials followed by gas chromatography with mass spectrometry.

PubMed

Masoum, Saeed; Gholami, Ali; Ghaheri, Salehe; Bouveresse, Delphine Jouan-Rimbaud; Cordella, Christophe B Y; Rutledge, Douglas N

2016-07-01

A new composite coating of polypyrrole and sodium lauryl ether sulfate was electrochemically prepared on a stainless-steel wire using cyclic voltammetry. The application and performance of the fiber was evaluated for the headspace solid-phase microextraction of a fragrance in aqueous bleach samples followed by gas chromatography combined with mass spectrometry to assess the fragrance stability in this kind of household cleaning product. To obtain a stable and efficient composite coating, parameters related to the coating process such as scan rate and numbers of cycles were optimized using a central composite design. In addition, the effects of various parameters on the extraction efficiency of the headspace solid-phase microextraction process such as extraction temperature and time, ionic strength, sample volume, and stirring rate were investigated by experimental design methods using Plackett-Burman and Doehlert designs. The optimum values of 53°C and 28 min for sample temperature and time, respectively, were found through response surface methodology. Results show that the combination of polypyrrole and sodium lauryl ether sulfate in a composite form presents desirable opportunities to produce new materials to study fragrance stability by headspace solid-phase microextraction. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Tungsten wire/FeCrAlY matrix turbine blade fabrication study

NASA Technical Reports Server (NTRS)

Melnyk, P.; Fleck, J. N.

1979-01-01

The objective was to establish a viable FRS monotape technology base to fabricate a complex, advanced turbine blade. All elements of monotape fabrication were addressed. A new process for incorporation of the matrix, including bi-alloy matrices, was developed. Bonding, cleaning, cutting, sizing, and forming parameters were established. These monotapes were then used to fabricate a 48 ply solid JT9D-7F 1st stage turbine blade. Core technology was then developed and first a 12 ply and then a 7 ply shell hollow airfoil was fabricated. As the fabrication technology advanced, additional airfoils incorporated further elements of sophistication, by introducing in sequence bonded root blocks, cross-plying, bi-metallic matrix, tip cap, trailing edge slots, and impingement inserts.

State of the metal core in nanosecond exploding wires and related phenomena

NASA Astrophysics Data System (ADS)

Sarkisov, G. S.; Sasorov, P. V.; Struve, K. W.; McDaniel, D. H.

2004-08-01

Experiments show that an expanding metal wire core that results from a nanosecond electrical explosion in vacuum consists primarily of three different states: solid, microdrop, and gas-plasma. The state of the wire core depends both on the amount of energy deposited before the voltage breakdown and on the heating conditions. For small amounts of deposited energy (on the order of solid-stage enthalpy), the wire core remains in a solid state or is partially disintegrated. For a high level of deposited energy (more than vaporization energy) the wire core is in a gas-plasma state. For an intermediate level of deposited energy (more than melting but less than vaporization), the wire disintegrates into hot liquid microdrops or clusters of submicron size. For a wire core in the cluster state, interferometry demonstrates weak (or even absent) phaseshift. Light emission shows a "firework effect"—the long late-time radiation related to the emission by the expanding cylinder of hot microparticles. For the wire core in a gas-plasma state, interferometry demonstrates a large phaseshift and a fast reduction in light emission due to adiabatic cooling of the expanding wire core. The simulation of this firework effect agrees well with experimental data, assuming submicron size and a temperature approaching boiling for the expanded microparticles cylinder.

Drug delivery properties of macroporous polystyrene solid foams.

PubMed

Canal, Cristina; Aparicio, Rosa Maria; Vilchez, Alejandro; Esquena, Jordi; García-Celma, Maria José

2012-01-01

Polymeric porous foams have been evaluated as possible new pharmaceutical dosage forms. These materials were obtained by polymerization in the continuous phase of highly concentrated emulsions prepared by the phase inversion temperature method. Their porosity, specific surface and surface topography were characterized, and the incorporation and release of active principles was studied using ketoprofen as model lipophilic molecule. Solid foams with very high pore volume, mainly inside macropores, were obtained by this method. The pore morphology of the materials was characterized, and very rough topography was observed, which contributed to their nearly superhydrophobic properties. These solid foams could be used as delivery systems for active principles with pharmaceutical interest, and in the present work ketoprofen was used as a model lipophilic molecule. Drug incorporation and release was studied from solid foam disks, using different concentrations of the loading solutions, achieving a delayed release with short lag-time.

Physically incorporated extraction phase of solid-phase microextraction by sol-gel technology.

PubMed

Liu, Wenmin; Hu, Yuan; Zhao, Jinghong; Xu, Yuan; Guan, Yafeng

2006-01-13

A sol-gel method for the preparation of solid-phase microextraction (SPME) fiber was described and evaluated. The extraction phase of poly(dimethysiloxane) (PDMS) containing 3% vinyl group was physically incorporated into the sol-gel network without chemical bonding. The extraction phase itself is then partly crosslinked at 320 degrees C, forming an independent polymer network and can withstand desorption temperature of 290 degrees C. The headspace extraction of BTX by the fiber SPME was evaluated and the detection limit of o-xylene was down to 0.26 ng/l. Extraction and determination of organophosphorus pesticides (OPPs) in water, orange juice and red wine by the SPME-GC thermionic specified detector (TSD) was validated. Limits of detection of the method for OPPs were below 10 ng/l except methidathion. Relative standard deviations (RSDs) were in the range of 1-20% for pesticides being tested.

Vertically aligned silicon microwire arrays of various lengths by repeated selective vapor-liquid-solid growth of n-type silicon/n-type silicon

NASA Astrophysics Data System (ADS)

Ikedo, Akihito; Kawashima, Takahiro; Kawano, Takeshi; Ishida, Makoto

2009-07-01

Repeated vapor-liquid-solid (VLS) growth with Au and PH3-Si2H6 mixture gas as the growth catalyst and silicon source, respectively, was used to construct n-type silicon/n-type silicon wire arrays of various lengths. Silicon wires of various lengths within an array could be grown by employing second growth over the first VLS grown wire. Additionally, the junction at the interface between the first and the second wires were examined. Current-voltage measurements of the wires exhibited linear behavior with a resistance of 850 Ω, confirming nonelectrical barriers at the junction, while bending tests indicated that the mechanical properties of the wire did not change.

A star-shaped polythiophene dendrimer coating for solid-phase microextraction of triazole agrochemicals.

PubMed

Abolghasemi, Mir Mahdi; Habibiyan, Rahim; Jaymand, Mehdi; Piryaei, Marzieh

2018-02-14

A nanostructured star-shaped polythiophene dendrimer was prepared and used as a fiber coating for headspace solid phase microextraction of selected triazolic pesticides (tebuconazole, hexaconazole, penconazole, diniconazole, difenoconazole, triticonazole) from water samples. The dendrimer with its large surface area was characterized by thermogravimetric analysis, UV-Vis spectroscopy and field emission scanning electron microscopy. It was placed on a stainless steel wire for use in SPME. The experimental conditions for fiber coating, extraction, stirring rate, ionic strength, pH value, desorption temperature and time were optimized. Following thermal desorption, the pesticides were quantified by GC-MS. Under optimum conditions, the repeatability (RSD) for one fiber (for n = 3) ranges from 4.3 to 5.6%. The detection limits are between 8 and 12 pg mL -1 . The method is fast, inexpensive (in terms of equipment), and the fiber has high thermal stability. Graphical abstract Schematic presentation of a nanostructured star-shaped polythiophene dendrimer for use in headspace solid phase microextraction of the triazolic pesticides (tebuconazole, hexaconazole, penconazole, diniconazole, difenoconazole, triticonazole). They were then quantified by gas chromatography-mass spectrometry.

Simple fabrication of solid phase microextraction fiber employing nitrogen-doped ordered mesoporous polymer by in situ polymerization.

PubMed

Zheng, Juan; Liang, Yeru; Liu, Shuqin; Jiang, Ruifen; Zhu, Fang; Wu, Dingcai; Ouyang, Gangfeng

2016-01-04

A combination of nitrogen-doped ordered mesoporous polymer (NOMP) and stainless steel wires led to highly sensitive, selective, and stable solid phase microextraction (SPME) fibers by in situ polymerization for the first time. The ordered structure of synthesized NOMP coating was illustrated by transmission electron microscopy (TEM) and X-ray diffraction (XRD), and microscopy analysis by scanning electron microscopy (SEM) confirmed a homogenous morphology of the NOMP-coated fiber. The NOMP-coated fiber was further applied for the extraction of organochlorine pesticides (OCPs) with direct-immersion solid-phase microextraction (DI-SPME) method followed by gas chromatography-mass spectrometry (GC-MS) quantification. Under the optimized conditions, low detection limits (0.023-0.77 ng L(-1)), a wide linear range (9-1500 ng L(-1)), good repeatability (3.5-8.1%, n=6) and excellent reproducibility (1.5-8.3%, n=3) were achieved. Moreover, the practical feasibility of the proposed method was evaluated by determining OCPs in environmental water samples with satisfactory recoveries. Copyright © 2015 Elsevier B.V. All rights reserved.

Development of a polymeric ionic liquid coating for direct-immersion solid-phase microextraction using polyhedral oligomeric silsesquioxane as cross-linker.

PubMed

Chen, Chunyan; Liang, Xiaotong; Wang, Jianping; Zou, Ying; Hu, Huiping; Cai, Qingyun; Yao, Shouzhuo

2014-06-27

A novel solid-phase microextraction (SPME) fiber was developed by chemical binding of a crosslinked polymeric ionic liquid (PIL) on the surface of an anodized Ti wire, and was applied in direct-immersion mode for the extraction of perfluorinated compounds (PFCs) from water samples coupled with high performance liquid chromatography-tandem mass spectrometry analysis. The PIL coatings were synthesized by using 1-vinyl-3-hexylimidazolium hexafluorophosphate as monomer and methylacryloyl-substituted polyhedral oligomeric silsesquioxane (POSS) as cross-linker via free radical reaction. The proposed fiber coating exhibited high mechanical stability due to the chemical bonding between the coating and the Ti wire surface. The integration of POSS reagent enhanced the organic solvent resistance of the coating. The parameters affecting the extraction performance of the fiber coating including extraction time, pH of solution, ionic strength and desorption conditions were optimized. The developed PIL-POSS fiber showed good linearity (R<0.998) between 0.1 and 50ngmL(-1) with method detection limits ranging from 0.005 to 0.08ngmL(-1) depending on the analyte, and with relative standard deviation for single-fiber repeatability and fiber-to-fiber reproducibility less than 8.6% and 9.5%, respectively. Copyright © 2014 Elsevier B.V. All rights reserved.

Development and application of a new solid-phase microextraction fiber by sol-gel technology on titanium wire.

PubMed

Es-haghi, Ali; Hosseini, Seyed Maryam; Khoshhesab, Zahra Monsef

2012-09-12

Novel solid-phase microextraction fibers were prepared based on sol-gel technique. Commonly used fused silica substrate was replaced by titanium wire which provided high strength and longer fiber life cycle. Titanium isopropoxide was employed as the precursor which provides a sol solution containing Ti-OH groups and shows more tendencies to the molecularly similar group on the substrate. Three different polymers, poly (dimethylsiloxane) (PDMS), poly(ethylenepropyleneglycol)-monobutyl ether (Ucon) and polyethylene glycol (PEG) were employed as coating polymer in preparing three different fibers. The applicability of these fibers was assessed for the headspace SPME (HS-SPME) of benzene, toluene, ethylbenzene and xylenes (BTEX) from water sample followed by gas chromatography-mass spectrometry (GC-MS). Effects of different parameters such as fiber coating type, extraction condition, desorption condition were investigated and optimized. Under the optimized conditions, LODs and LOQs of 0.75-10 μg L(-1) (S/N=3) and 1-20 μg L(-1) (S/N=10) were respectively obtained. The method showed linearity in the range of 10-25,000 μg L(-1) with correlation coefficient of >0.99. The relative standard deviation was less than 8%. Copyright © 2012 Elsevier B.V. All rights reserved.

Electrochemical preparation of polyaniline-polypyrrole solid-phase microextraction coating and its application in the GC determination of several esters.

PubMed

Zhao, Shasha; Wu, Mian; Zhao, Faqiong; Zeng, Baizhao

2013-12-15

A novel polyaniline-polypyrrole (PANI-PPY) composite film coated stainless steel wire was prepared by cyclic voltammetry. Firstly, PANI was electrodeposited on a stainless steel wire from a solution containing 0.1 M aniline and 1M HNO3, after the PANI coating was dried in air PPY was electrodeposited on it from a solution containing 0.1 M pyrrole and 0.1 M p-methylbenzene sulfonic acid. The resulting PANI-PPY fiber showed reticulate structure and had large specific surface area. When it was used for the headspace solid-phase microextraction of several esters (i.e. methyl anthranilate, ethyl-o-aminobenzoate, dimethyl phthalate, methyl laurate, and diethyl phthalate), followed by gas chromatographic determination, it presented higher extraction capability in comparison with PPY and PANI coatings. Under the optimized conditions, the linear ranges were 0.07-300 μg L(-1) and the detection limits were 0.05-0.38 μg L(-1) for different esters. The PANI-PPY fiber also showed high durability, after being used for about 160 times its extraction capacity only changed a little. The proposed method was successfully applied to the determination of these esters in real samples and the recoveries were 90-102%. © 2013 Elsevier B.V. All rights reserved.

Synthesis and Characterization of CuFe 2O 4 Nano/Submicron Wire–Carbon Nanotube Composites as Binder-free Anodes for Li-Ion Batteries

DOE PAGES

Wang, Lei; Bock, David C.; Li, Jing; ...

2018-02-20

Here, a series of one-dimensional CuFe 2O 4 nano/sub-micron wires possessing different diameters, crystal phases, and crystal sizes have been successfully generated using a facile template-assisted co precipitation reaction at room temperature, followed by a short post-annealing process. The diameter and the crystal structure of the resulting CuFe 2O4 (CFO) wires were judiciously tuned by varying the pore size of the template and the post-annealing temperature, respectively. Carbon nanotubes (CNTs) were incorporated to generate CFO-CNT binder-free anodes, and multiple characterization techniques were employed with the goal of delineating the relationships between electrochemical behavior and the properties of both the CFOmore » wires (crystal phase, wire diameter, crystal size) and the electrode architecture (binder-free vs. conventionally prepared approaches). The study reveals several notable findings. First, the crystal phase (cubic or tetragonal) did not influence the electrochemical behavior in this CFO system. Second, regarding crystallite size and wire diameter, CFO wires with larger crystallite sizes exhibit improved cycling stability, while wires possessing smaller diameters exhibiting higher capacities. Finally, the electrochemical behavior is strongly influenced by the electrode architecture, with CFO-CNT binder-free electrodes demonstrating significantly higher capacities and cycling stability compared to conventionally prepared coatings. The mechanism(s) associated with the high capacities under low current density but limited electrochemical reversibility of CFO electrodes under high current density were probed via x-ray absorption spectroscopy (XAS) mapping with sub-micron spatial resolution for the first time. Results suggest that the capacity of the binder-free electrodes under high rate is limited by the irreversible formation of Cu 0, as well as limited reduction of Fe 3+, to Fe 2+ not Fe 0. The results (1) shed fundamental insight into the reversibility of CuFe 2O 4 materials cycled at high current density and (2) demonstrate that a synergistic effort to control both active material morphology and electrode architecture is an effective strategy for optimizing electrochemical behavior.« less

Synthesis and Characterization of CuFe 2O 4 Nano/Submicron Wire–Carbon Nanotube Composites as Binder-free Anodes for Li-Ion Batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Lei; Bock, David C.; Li, Jing

Here, a series of one-dimensional CuFe 2O 4 nano/sub-micron wires possessing different diameters, crystal phases, and crystal sizes have been successfully generated using a facile template-assisted co precipitation reaction at room temperature, followed by a short post-annealing process. The diameter and the crystal structure of the resulting CuFe 2O4 (CFO) wires were judiciously tuned by varying the pore size of the template and the post-annealing temperature, respectively. Carbon nanotubes (CNTs) were incorporated to generate CFO-CNT binder-free anodes, and multiple characterization techniques were employed with the goal of delineating the relationships between electrochemical behavior and the properties of both the CFOmore » wires (crystal phase, wire diameter, crystal size) and the electrode architecture (binder-free vs. conventionally prepared approaches). The study reveals several notable findings. First, the crystal phase (cubic or tetragonal) did not influence the electrochemical behavior in this CFO system. Second, regarding crystallite size and wire diameter, CFO wires with larger crystallite sizes exhibit improved cycling stability, while wires possessing smaller diameters exhibiting higher capacities. Finally, the electrochemical behavior is strongly influenced by the electrode architecture, with CFO-CNT binder-free electrodes demonstrating significantly higher capacities and cycling stability compared to conventionally prepared coatings. The mechanism(s) associated with the high capacities under low current density but limited electrochemical reversibility of CFO electrodes under high current density were probed via x-ray absorption spectroscopy (XAS) mapping with sub-micron spatial resolution for the first time. Results suggest that the capacity of the binder-free electrodes under high rate is limited by the irreversible formation of Cu 0, as well as limited reduction of Fe 3+, to Fe 2+ not Fe 0. The results (1) shed fundamental insight into the reversibility of CuFe 2O 4 materials cycled at high current density and (2) demonstrate that a synergistic effort to control both active material morphology and electrode architecture is an effective strategy for optimizing electrochemical behavior.« less

Wire Composition: Its Effect on Metal Disintegration and Particle Formation in Twin-Wire Arc-Spraying Process

NASA Astrophysics Data System (ADS)

Tillmann, W.; Abdulgader, M.

2013-03-01

The wire tips in twin-wire arc-spraying (TWAS) are heated in three different zones. A high-speed camera was used to observe the melting behavior, metal breakup, and particle formation under different operating conditions. In zone (I), the wire tips are melted (liquidus metal) and directly atomized in the form of smaller droplets. Their size is a function of the specific properties of the molten metal and the exerting aerodynamic forces. Zone (II) is directly beneath zone (I) and the origin of the extruded metal sheets at the wire tips. The extruded metal sheets in the case of cored wires are shorter than those observed while using solid wires. In this study, the effects of adjustable parameters and powder filling on melting behavior, particle formation, and process instability were revealed, and a comparison between solid and cored wires was made. The findings can improve the accuracy of the TWAS process modeling.

Solid-phase synthesis of smac peptidomimetics incorporating triazoloprolines and biarylalanines.

PubMed

Le Quement, Sebastian T; Ishoey, Mette; Petersen, Mette T; Thastrup, Jacob; Hagel, Grith; Nielsen, Thomas E

2011-11-14

Apoptotic induction mechanisms are of crucial importance for the general homeostasis of multicellular organisms. In cancer the apoptotic pathways are downregulated, which, at least partly, is due to an abundance of inhibitors of apoptosis proteins (IAPs) that block the apoptotic cascade by deactivating proteolytic caspases. The Smac protein has an antagonistic effect on IAPs, thus providing structural clues for the synthesis of new pro-apoptotic compounds. Herein, we report a solid-phase approach for the synthesis of Smac-derived tetrapeptide libraries. On the basis of a common (N-Me)AVPF sequence, peptides incorporating triazoloprolines and biarylalanines were synthesized by means of Cu(I)-catalyzed azide-alkyne cycloaddition and Pd-catalyzed Suzuki cross-coupling reactions. Solid-phase procedures were optimized to high efficiency, thus accessing all products in excellent crude purities and yields (both typically above 90%). The peptides were subjected to biological evaluation in a live/dead cellular assay which revealed that structural decorations on the AVPF sequence indeed are highly important for cytotoxicity toward HeLa cells.

Development of SiAlON materials

NASA Technical Reports Server (NTRS)

Layden, G. K.

1977-01-01

Cold pressing and sintering techniques were used to produce ceramic bodies in which the major phase was beta prime Si3-Al-O-N4 solid solution. A variety of foreign oxides were used to promote liquid phase sintering, and this resulted in the incorporation of additional solid phases in the ceramic bodies which controlled elevated temperature properties. None of the bodies studied to date exhibited both adequate high temperature mechanical properties and oxidation resistance. Criteria are suggested to guide the formulation of bodies with improved high temperature properties.

Boron nitride nanowires synthesis via a simple chemical vapor deposition at 1200 °C

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahmad, Pervaiz; Khandaker, Mayeen Uddin; Amin, Yusoff Mohd

2015-04-24

A very simple chemical vapor deposition technique is used to synthesize high quality boron nitride nanowires at 1200 °C within a short growth duration of 30 min. FESEM micrograph shows that the as-synthesized boron nitride nanowires have a clear wire like morphology with diameter in the range of ∼20 to 150 nm. HR-TEM confirmed the wire-like structure of boron nitride nanowires, whereas XPS and Raman spectroscopy are used to find out the elemental composition and phase of the synthesized material. The synthesized boron nitride nanowires have potential applications as a sensing element in solid state neutron detector, neutron capture therapy and microelectronicmore » devices with uniform electronic properties.« less

7 CFR 1755.701 - Scope.

Code of Federal Regulations, 2011 CFR

2011-01-01

...) This section covers the requirements for aerial service wires intended for aerial subscriber drops. (b) The aerial service wires can be either copper coated steel reinforced or nonmetallic reinforced...) The conductors are solid copper-covered steel wires. (2) The wire structure is completed by insulating...

7 CFR 1755.701 - Scope.

Code of Federal Regulations, 2010 CFR

2010-01-01

...) This section covers the requirements for aerial service wires intended for aerial subscriber drops. (b) The aerial service wires can be either copper coated steel reinforced or nonmetallic reinforced...) The conductors are solid copper-covered steel wires. (2) The wire structure is completed by insulating...

Reduction and Simultaneous Removal of 99 Tc and Cr by Fe(OH) 2 (s) Mineral Transformation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saslow, Sarah A.; Um, Wooyong; Pearce, Carolyn I.

Technetium (Tc) remains a priority remediation concern due to persistent challenges, including rapid re-oxidation of immobilized Tc, and competing contaminants, e.g. Cr(VI), that inhibit targeted Tc reduction and incorporation into stable mineral phases. Here Fe(OH) 2(s) is investigated as a comprehensive solution for overcoming these challenges, by serving as both the reductant, (Fe(II)), and immobilization agent to form Tc-incorporated magnetite (Fe 3O 4). Trace metal analysis suggests removal of Tc(VII) and Cr(VI) from solution occurs simultaneously; however, complete removal and reduction of Cr(VI) is achieved earlier than the removal/reduction of co-mingled Tc(VII). Bulk oxidation state analysis of the magnetite solidmore » phase by XANES confirms that the majority of Tc is Tc(IV), which is corroborated by XPS. Furthermore, EXAFS results show successful Tc(IV) incorporation into magnetite octahedral sites without additional substitution of Cr or Tc into neighboring Fe octahedral sites. XPS analysis of Cr confirms reduction to Cr(III) and the formation of a Cr-incorporated spinel, Cr2O 3, and Cr(OH)3 phases. Spinel (modeled as Fe 3O 4), goethite, and feroxyhyte are detected in all reacted solid phase samples analyzed by XRD, where Tc(IV) incorporation has little effect on the spinel lattice structure. In the presence of Cr(III) a spinel phase along the magnetite-chromite (Fe 3O 4-FeCr 2O 4) solid-solution line is formed.« less

Compressibility determination by electrical resistance measurement: a universal method for both crystalline and amorphous solids

NASA Astrophysics Data System (ADS)

Yan, Xiaozhi; He, Duanwei; Xu, Chao; Ren, Xiangting; Zhou, Xiaoling; Liu, Shenzuo

2012-12-01

A new method is introduced for investigating the compressibility of solids under high pressure by in situ electrical resistance measurement of a manganin wire, which is wrapped around the sample. This method does not rely on the lattice parameters measurement, and the continuous volume change of the sample versus pressure can be obtained. Therefore, it is convenient to look at the compressibility of solids, especially for the X-ray diffraction amorphous materials. The I-II and II-III phase transition of Bi accompanying with volume change of 4.5% and 3.5% has been detected using the method, respectively, while the volume change for the phase transition of Tl occurring at 3.67 GPa is determined as 0.5%. The fit of the third-order Birch-Murnaghan equation of state to our data yields a zero-pressure bulk modulus K 0=28.98±0.03 GPa for NaCl and 6.97±0.02 GPa for amorphous red phosphorus.

Synthesis of peptides containing overlapping lanthionine bridges on the solid phase: an analogue of rings D and E of the lantibiotic nisin.

PubMed

Mothia, Begum; Appleyard, Antony N; Wadman, Sjoerd; Tabor, Alethea B

2011-08-19

A methodology for the solid-phase synthesis of the overlapping lanthionine bridges found in many lantibiotics has been developed. A novel Teoc/TMSE-protected lanthionine derivative has been synthesized, and this lanthionine, and an Aloc/allyl-protected lanthionine derivative, have been incorporated into a linear peptide using solid-phase peptide synthesis. Selective deprotection of the silyl protecting groups, followed by sequential cyclization, deprotection of the allyl protecting groups, and further cyclization, enabled the regioselective formation of an analogue of rings D and E of nisin. © 2011 American Chemical Society

Two-phase non-Newtonian hydrodynamic modeling of slurries

NASA Astrophysics Data System (ADS)

Wang, C. S.; Lyczkowski, R. W.; Berry, G. F.

The two-phase hydrodynamic theory of fluid/solid flow has been extended to incorporate the constitutive relationship for power-law non-Newtonian behavior. A model has been developed to predict the spatial and temporal variations in solids and liquid velocities and concentration of non-Newtonian slurries under high shear rates in diesel engine injection systems. Comparisons between the present non-Newtonian two-phase theory and the conventional theory have also been made. Selected results for diesel injection nozzle applications are presented. The results from this model can be used to calculate directly the erosion rates at the nozzle boundaries and the solids loading at the nozzle exit.

Two-dimensional solid-phase extraction strategy for the selective enrichment of aminoglycosides in milk.

PubMed

Shen, Aijin; Wei, Jie; Yan, Jingyu; Jin, Gaowa; Ding, Junjie; Yang, Bingcheng; Guo, Zhimou; Zhang, Feifang; Liang, Xinmiao

2017-03-01

An orthogonal two-dimensional solid-phase extraction strategy was established for the selective enrichment of three aminoglycosides including spectinomycin, streptomycin, and dihydrostreptomycin in milk. A reversed-phase liquid chromatography material (C 18 ) and a weak cation-exchange material (TGA) were integrated in a single solid-phase extraction cartridge. The feasibility of two-dimensional clean-up procedure that experienced two-step adsorption, two-step rinsing, and two-step elution was systematically investigated. Based on the orthogonality of reversed-phase and weak cation-exchange procedures, the two-dimensional solid-phase extraction strategy could minimize the interference from the hydrophobic matrix existing in traditional reversed-phase solid-phase extraction. In addition, high ionic strength in the extracts could be effectively removed before the second dimension of weak cation-exchange solid-phase extraction. Combined with liquid chromatography and tandem mass spectrometry, the optimized procedure was validated according to the European Union Commission directive 2002/657/EC. A good performance was achieved in terms of linearity, recovery, precision, decision limit, and detection capability in milk. Finally, the optimized two-dimensional clean-up procedure incorporated with liquid chromatography and tandem mass spectrometry was successfully applied to the rapid monitoring of aminoglycoside residues in milk. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fabrication of Nanovoid-Imbedded Bismuth Telluride with Low Dimensional System

NASA Technical Reports Server (NTRS)

Chu, Sang-Hyon (Inventor); Choi, Sang H. (Inventor); Kim, Jae-Woo (Inventor); Park, Yeonjoon (Inventor); Elliott, James R. (Inventor); King, Glen C. (Inventor); Stoakley, Diane M. (Inventor)

2013-01-01

A new fabrication method for nanovoids-imbedded bismuth telluride (Bi--Te) material with low dimensional (quantum-dots, quantum-wires, or quantum-wells) structure was conceived during the development of advanced thermoelectric (TE) materials. Bismuth telluride is currently the best-known candidate material for solid-state TE cooling devices because it possesses the highest TE figure of merit at room temperature. The innovative process described here allows nanometer-scale voids to be incorporated in Bi--Te material. The final nanovoid structure such as void size, size distribution, void location, etc. can be also controlled under various process conditions.

Processing, Structural Characterization and Comparative Studies on Uniaxial Tensile Properties of a New Type of Porous Twisted Wire Material

PubMed Central

Wu, Fei; Zhou, Zhaoyao; Duan, Liuyang; Xiao, Zhiyu

2015-01-01

A self-developed rotary multi-cutter device cuts stainless steel wire ropes into segments to fabricate twisted wires. Stainless steel porous twisted wire materials (PTWMs) with a spatial composite intertexture structure are produced by the compaction and subsequent vacuum solid-phase sintering of twisted wires. The stainless steel PTWMs show two types of typical uniaxial tensile failure modes, i.e., a 45° angle fracture mode and an auxetic failure mode (the PTWMs expand along the direction perpendicular to the tension). The effects of the sintering parameters, porosities, wire diameters, and sampling direction on the tensile properties of the PTWMs are carefully investigated. By increasing the sintering temperature from 1130 °C to 1330 °C, the tensile strength of the PTWMs with 70% target porosity increased from 7.7 MPa to 28.6 MPa and the total failure goes down to 50%. When increasing the sintering time from 90 min to 150 min, the tensile strength increases from 12.4 MPa to 19.1 MPa and the total failure elongation drops to 78.6%. The tensile strength of the PTWMs increases from 28.9 MPa to 112.7 MPa with decreasing porosity from 69.5% to 46.0%, and the total failure elongation also increases from 14.8% to 40.7%. The tensile strength and the failure strain of the PTWMs with fine wires are higher than those of the PTWMs with coarse wires under the same porosity. Sampling direction has a small influence on the tensile properties of the PTWMs. PMID:28793526

Processing, Structural Characterization and Comparative Studies on Uniaxial Tensile Properties of a New Type of Porous Twisted Wire Material.

PubMed

Wu, Fei; Zhou, Zhaoyao; Duan, Liuyang; Xiao, Zhiyu

2015-08-27

A self-developed rotary multi-cutter device cuts stainless steel wire ropes into segments to fabricate twisted wires. Stainless steel porous twisted wire materials (PTWMs) with a spatial composite intertexture structure are produced by the compaction and subsequent vacuum solid-phase sintering of twisted wires. The stainless steel PTWMs show two types of typical uniaxial tensile failure modes, i.e. , a 45° angle fracture mode and an auxetic failure mode (the PTWMs expand along the direction perpendicular to the tension). The effects of the sintering parameters, porosities, wire diameters, and sampling direction on the tensile properties of the PTWMs are carefully investigated. By increasing the sintering temperature from 1130 °C to 1330 °C, the tensile strength of the PTWMs with 70% target porosity increased from 7.7 MPa to 28.6 MPa and the total failure goes down to 50%. When increasing the sintering time from 90 min to 150 min, the tensile strength increases from 12.4 MPa to 19.1 MPa and the total failure elongation drops to 78.6%. The tensile strength of the PTWMs increases from 28.9 MPa to 112.7 MPa with decreasing porosity from 69.5% to 46.0%, and the total failure elongation also increases from 14.8% to 40.7%. The tensile strength and the failure strain of the PTWMs with fine wires are higher than those of the PTWMs with coarse wires under the same porosity. Sampling direction has a small influence on the tensile properties of the PTWMs.

A mixed-penalty biphasic finite element formulation incorporating viscous fluids and material interfaces.

PubMed

Chan, B; Donzelli, P S; Spilker, R L

2000-06-01

The fluid viscosity term of the fluid phase constitutive equation and the interface boundary conditions between biphasic, solid and fluid domains have been incorporated into a mixed-penalty finite element formulation of the linear biphasic theory for hydrated soft tissue. The finite element code can now model a single-phase viscous incompressible fluid, or a single-phase elastic solid, as limiting cases of a biphasic material. Interface boundary conditions allow the solution of problems involving combinations of biphasic, fluid and solid regions. To incorporate these conditions, the volume-weighted mixture velocity is introduced as a degree of freedom at interface nodes so that the kinematic continuity conditions are satisfied by conventional finite element assembly techniques. Results comparing our numerical method with an independent, analytic solution for the problem of Couette flow over rigid and deformable porous biphasic layers show that the finite element code accurately predicts the viscous fluid flows and deformation in the porous biphasic region. Thus, the analysis can be used to model the interface between synovial fluid and articular cartilage in diarthrodial joints. This is an important step toward modeling and understanding the mechanisms of joint lubrication and another step toward fully modeling the in vivo behavior of a diarthrodial joint.

Structure, growth kinetics, and ledge flow during vapor-solid-solid growth of copper-catalyzed silicon nanowires.

PubMed

Wen, C-Y; Reuter, M C; Tersoff, J; Stach, E A; Ross, F M

2010-02-10

We use real-time observations of the growth of copper-catalyzed silicon nanowires to determine the nanowire growth mechanism directly and to quantify the growth kinetics of individual wires. Nanowires were grown in a transmission electron microscope using chemical vapor deposition on a copper-coated Si substrate. We show that the initial reaction is the formation of a silicide, eta'-Cu(3)Si, and that this solid silicide remains on the wire tips during growth so that growth is by the vapor-solid-solid mechanism. Individual wire directions and growth rates are related to the details of orientation relation and catalyst shape, leading to a rich morphology compared to vapor-liquid-solid grown nanowires. Furthermore, growth occurs by ledge propagation at the silicide/silicon interface, and the ledge propagation kinetics suggest that the solubility of precursor atoms in the catalyst is small, which is relevant to the fabrication of abrupt heterojunctions in nanowires.

An Investigation into the Comparative Costs of Additive Manufacture vs. Machine from Solid for Aero Engine Parts

DTIC Science & Technology

2006-05-01

welding power sources are not totally efficient at converting power drawn from the wall into heat energy used for the welding process . TIG sources are...Powder bed + Laser • Wire + Laser • Wire + Electron Beam • Wire + TIG Each system has its own unique attributes in terms of process variables...relative economics of producing a near net shape by Additive Manufacturing (AM) processes compared with traditional machine from solid processes (MFS

Rapid screening of methamphetamines in human serum by headspace solid-phase microextraction using a dodecylsulfate-doped polypyrrole film coupled to ion mobility spectrometry.

PubMed

Alizadeh, Naader; Mohammadi, Abdorreza; Tabrizchi, Mahmoud

2008-03-07

A simple, rapid and highly sensitive method for simultaneous analysis of methamphetamine (MA) and 3,4-methylenedioxy methamphetamine (MDMA) in human serum was developed using the solid-phase microextraction (SPME) combined with ion mobility spectrometry (IMS). A dodecylsulfate-doped polypyrrole (PPy-DS) was applied as a new fiber for SPME. Electrochemically polymerized PPy is formed on the surface of a platinum wire and will contain charge-compensating anion (dodecylsulfate) incorporated during synthesis using cyclic voltammetry (CV) technique. The extraction properties of the fiber to MA and MDMA were examined, using a headspace-SPME (HS-SPME) device and thermal desorption in injection port of IMS. The results show that PPy-DS as a SPME fiber coating is suitable for the successful extraction of these compounds. This method is suitable for the identification and determination of MAs, is not time-consuming, requires small quantities of sample and does not require any derivatization. Parameters like pH, extraction time, ionic strength, and temperature of the sample were studied and optimized to obtain the best extraction results. The HS-SPME-IMS method provided good repeatability (RSDs<7.8 %) for spiked serum samples. The calibration graphs were linear in the range of 20-4000 ng ml(-1) (R(2)>0.99) and detection limits for MDMA and MA were 5 and 8 ng ml(-1), respectively. HS-SPME-IMS of non-spiked serum sample provided a spectrum without any peak from the matrix, supporting an effective sample clean-up. Finally, the proposed method was applied for analysis one of the ecstasy tablet.

Bright and durable field-emission source derived from frozen refractory-metal Taylor cones

DOE PAGES

Hirsch, Gregory

2017-02-22

A novel method for creating conical field-emission structures possessing unusual and desirable physical characteristics is described. This process is accomplished by solidification of electrostatically formed high-temperature Taylor cones created on the ends of laser melted refractory-metal wires. Extremely rapid freezing ensures that the resultant solid structures preserve the shape and surface smoothness of the flawless liquid Taylor-cones to a very high degree. The method also enables in situ and rapid restoration of the frozen cones to their initial pristine state after undergoing physical degradation during use. This permits maximum current to be delivered without excessive concern for any associated reductionmore » in field-emitter lifetime resulting from operation near or even above the damage threshold. In addition to the production of field emitters using polycrystalline wires as a substrate, the feasibility of producing monocrystalline frozen Taylor-cones having reproducible crystal orientation by growth on single-crystal wires was demonstrated. Finally, the development of the basic field-emission technology, progress to incorporate it into a pulsed electron gun employing laser-assisted field emission for ultrafast experiments, and some additional advances and opportunities are discussed.« less

Bright and durable field-emission source derived from frozen refractory-metal Taylor cones

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hirsch, Gregory

A novel method for creating conical field-emission structures possessing unusual and desirable physical characteristics is described. This process is accomplished by solidification of electrostatically formed high-temperature Taylor cones created on the ends of laser melted refractory-metal wires. Extremely rapid freezing ensures that the resultant solid structures preserve the shape and surface smoothness of the flawless liquid Taylor-cones to a very high degree. The method also enables in situ and rapid restoration of the frozen cones to their initial pristine state after undergoing physical degradation during use. This permits maximum current to be delivered without excessive concern for any associated reductionmore » in field-emitter lifetime resulting from operation near or even above the damage threshold. In addition to the production of field emitters using polycrystalline wires as a substrate, the feasibility of producing monocrystalline frozen Taylor-cones having reproducible crystal orientation by growth on single-crystal wires was demonstrated. Finally, the development of the basic field-emission technology, progress to incorporate it into a pulsed electron gun employing laser-assisted field emission for ultrafast experiments, and some additional advances and opportunities are discussed.« less

A High-Throughput Process for the Solid-Phase Purification of Synthetic DNA Sequences

PubMed Central

Grajkowski, Andrzej; Cieślak, Jacek; Beaucage, Serge L.

2017-01-01

An efficient process for the purification of synthetic phosphorothioate and native DNA sequences is presented. The process is based on the use of an aminopropylated silica gel support functionalized with aminooxyalkyl functions to enable capture of DNA sequences through an oximation reaction with the keto function of a linker conjugated to the 5′-terminus of DNA sequences. Deoxyribonucleoside phosphoramidites carrying this linker, as a 5′-hydroxyl protecting group, have been synthesized for incorporation into DNA sequences during the last coupling step of a standard solid-phase synthesis protocol executed on a controlled pore glass (CPG) support. Solid-phase capture of the nucleobase- and phosphate-deprotected DNA sequences released from the CPG support is demonstrated to proceed near quantitatively. Shorter than full-length DNA sequences are first washed away from the capture support; the solid-phase purified DNA sequences are then released from this support upon reaction with tetra-n-butylammonium fluoride in dry dimethylsulfoxide (DMSO) and precipitated in tetrahydrofuran (THF). The purity of solid-phase-purified DNA sequences exceeds 98%. The simulated high-throughput and scalability features of the solid-phase purification process are demonstrated without sacrificing purity of the DNA sequences. PMID:28628204

Nanostructured lipid carriers: effect of solid phase fraction and distribution on the release of encapsulated materials.

PubMed

Dan, Nily

2014-11-25

Emulsions, solid lipid nanoparticles (SLN), and nanostructured lipid carriers (NLC) containing a mix of liquid and solid domains are of interest as encapsulation vehicles for hydrophobic compounds. Studies of the release rate from these particles yield contradictory results: Some find that increasing the fraction of solid phase increases the rate of release and others the opposite. In this paper we study the release of encapsulated materials from lipid-based nanoparticles using Monte Carlo simulations. We find that, quite surprisingly, the release rate is largely insensitive to the size of solid domains or the fraction of solid phase. However, the distribution of the domains significantly affects the rate of release: Solid domains located at the interface with the surrounding solution inhibit transport, while nanoparticles where the solid domains are concentrated in the center enhance it. The latter can lead to release rates in NLCs that are faster than in the equivalent emulsions. We conclude that controlling the release rate from NLCs requires the ability to determine the location and distribution of the solid phase, which may be achieved through choice of the surfactants stabilizing the particles, incorporation of nucleation sites, and/or the cooling rates and temperatures.

Spontaneous, Defect-Free Kinking via Capillary Instability during Vapor-Liquid-Solid Nanowire Growth.

PubMed

Li, Yanying; Wang, Yanming; Ryu, Seunghwa; Marshall, Ann F; Cai, Wei; McIntyre, Paul C

2016-03-09

Kinking, a common anomaly in nanowire (NW) vapor-liquid-solid (VLS) growth, represents a sudden change of the wire's axial growth orientation. This study focuses on defect-free kinking during germanium NW VLS growth, after nucleation on a Ge (111) single crystal substrate, using Au-Ge catalyst liquid droplets of defined size. Statistical analysis of the fraction of kinked NWs reveals the dependence of kinking probability on the wire diameter and the growth temperature. The morphologies of kinked Ge NWs studied by electron microscopy show two distinct, defect-free, kinking modes, whose underlying mechanisms are explained with the help of 3D multiphase field simulations. Type I kinking, in which the growth axis changes from vertical [111] to ⟨110⟩, was observed in Ge NWs with a nominal diameter of ∼ 20 nm. This size coincides with a critical diameter at which a spontaneous transition from ⟨111⟩ to ⟨110⟩ growth occurs in the phase field simulations. Larger diameter NWs only exhibit Type II kinking, in which the growth axis changes from vertical [111] directly to an inclined ⟨111⟩ axis during the initial stages of wire growth. This is caused by an error in sidewall facet development, which produces a shrinkage in the area of the (111) growth facet with increasing NW length, causing an instability of the Au-Ge liquid droplet at the tip of the NW.

Design requirements for rigid printed wiring boards and assemblies. NASA Handbook

NASA Technical Reports Server (NTRS)

1986-01-01

The NASA requirements for assuring reliable rigid printed wiring board design are prescribed. Basic considerations necessary to assure reliable rigid printed wiring board design are described and incorporated.

Pig manure treatment by filtration.

PubMed

Kowalski, Zygmunt; Makara, Agnieszka; Matýsek, Dalibor; Hoffmann, Józef; Hoffmann, Krystyna

2013-01-01

A study of new pig manure treatment and filtration process was carried out. The advantage of the worked out technology is the method of incorporation of crystalline phase into solid organic part of manure. The obtained new solid phase of manure contains about 50% of crystalline phase forming a filtration aid that enables high effectiveness of manure filtration. The filtration rate of manure separation into solid and liquid fractions with pressure filter may achieve 1300-3000 kg/m(2)/h. The method makes it possible to maintain an overall average pollutant removal performance 90% for the chemical oxygen demand COD, > 99% for the suspended solids SS, to 47% for the total nitrogen content. The obtained results showed that the proposed technology being efficient and simple offers a possible solution to pig manure problems.

Ionic liquid supported on an electrodeposited polycarbazole film for the headspace solid-phase microextraction and gas chromatography determination of aromatic esters.

PubMed

Feng, Yuanyuan; Zhao, Faqiong; Zeng, Baizhao

2015-05-01

A polycarbazole film was electrodeposited on a stainless-steel wire from a solution of N,N-dimethylformamide/propylene carbonate (1:9 v/v) containing 0.10 M carbazole and 0.10 M tetrabutylammonium perchlorate. The obtained polycarbazole fiber was immersed into an ionic liquid (1-hydroxyethyl-3-methyl imidazolium bis[(trifluoromethyl)sulfonyl]imide) solution (in dimethylsulfoxide) for 30 min, followed by drying under an infrared lamp. The resulting polycarbazole/ionic liquid fiber was applied to the headspace solid-phase microextraction and determination of aromatic esters by coupling with gas chromatography and flame ionization detection. Under the optimized conditions, the limits of detection were below 61 ng/L (S/N = 3) and the linear ranges were 0.061-500 μg/L with correlation coefficients above 0.9876. The relative standard deviations were below 4.8% (n = 5) for a single fiber, and below 9.9% for multi-fiber (n = 4). This fiber also exhibited good stability. It could be used for more than 160 times of headspace solid-phase microextraction and could withstand a high temperature up to 350°C. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Stochastic analysis of surface roughness models in quantum wires

NASA Astrophysics Data System (ADS)

Nedjalkov, Mihail; Ellinghaus, Paul; Weinbub, Josef; Sadi, Toufik; Asenov, Asen; Dimov, Ivan; Selberherr, Siegfried

2018-07-01

We present a signed particle computational approach for the Wigner transport model and use it to analyze the electron state dynamics in quantum wires focusing on the effect of surface roughness. Usually surface roughness is considered as a scattering model, accounted for by the Fermi Golden Rule, which relies on approximations like statistical averaging and in the case of quantum wires incorporates quantum corrections based on the mode space approach. We provide a novel computational approach to enable physical analysis of these assumptions in terms of phase space and particles. Utilized is the signed particles model of Wigner evolution, which, besides providing a full quantum description of the electron dynamics, enables intuitive insights into the processes of tunneling, which govern the physical evolution. It is shown that the basic assumptions of the quantum-corrected scattering model correspond to the quantum behavior of the electron system. Of particular importance is the distribution of the density: Due to the quantum confinement, electrons are kept away from the walls, which is in contrast to the classical scattering model. Further quantum effects are retardation of the electron dynamics and quantum reflection. Far from equilibrium the assumption of homogeneous conditions along the wire breaks even in the case of ideal wire walls.

Individual differences in human brain development.

PubMed

Brown, Timothy T

2017-01-01

This article discusses recent scientific advances in the study of individual differences in human brain development. Focusing on structural neuroimaging measures of brain morphology and tissue properties, two kinds of variability are related and explored: differences across individuals of the same age and differences across age as a result of development. A recent multidimensional modeling study is explained, which was able to use brain measures to predict an individual's chronological age within about one year on average, in children, adolescents, and young adults between 3 and 20 years old. These findings reveal great regularity in the sequence of the aggregate brain state across different ages and phases of development, despite the pronounced individual differences people show on any single brain measure at any given age. Future research is suggested, incorporating additional measures of brain activity and function. WIREs Cogn Sci 2017, 8:e1389. doi: 10.1002/wcs.1389 For further resources related to this article, please visit the WIREs website. © 2016 The Authors. WIREs Cognitive Science published by Wiley Periodicals, Inc.

Solid phase microextraction device using aerogel

DOEpatents

Miller, Fred S.; Andresen, Brian D.

2005-06-14

A sample collection substrate of aerogel and/or xerogel materials bound to a support structure is used as a solid phase microextraction (SPME) device. The xerogels and aerogels may be organic or inorganic and doped with metals or other compounds to target specific chemical analytes. The support structure is typically formed of a glass fiber or a metal wire (stainless steel or kovar). The devices are made by applying gel solution to the support structures and drying the solution to form aerogel or xerogel. Aerogel particles may be attached to the wet layer before drying to increase sample collection surface area. These devices are robust, stable in fields of high radiation, and highly effective at collecting gas and liquid samples while maintaining superior mechanical and thermal stability during routine use. Aerogel SPME devices are advantageous for use in GC/MS analyses due to their lack of interfering background and tolerance of GC thermal cycling.

Method for preparing a solid phase microextraction device using aerogel

DOEpatents

Miller, Fred S [Bethel Island, CA; Andresen, Brian D [Livermore, CA

2006-10-24

A sample collection substrate of aerogel and/or xerogel materials bound to a support structure is used as a solid phase microextraction (SPME) device. The xerogels and aerogels may be organic or inorganic and doped with metals or other compounds to target specific chemical analytes. The support structure is typically formed of a glass fiber or a metal wire (stainless steel or kovar). The devices are made by applying gel solution to the support structures and drying the solution to form aerogel or xerogel. Aerogel particles may be attached to the wet layer before drying to increase sample collection surface area. These devices are robust, stable in fields of high radiation, and highly effective at collecting gas and liquid samples while maintaining superior mechanical and thermal stability during routine use. Aerogel SPME devices are advantageous for use in GC/MS analyses due to their lack of interfering background and tolerance of GC thermal cycling.

Synthesis of Sulfotyrosine-Containing Peptides by Incorporating Fluorosulfated Tyrosine Using an Fmoc-Based Solid-Phase Strategy.

PubMed

Chen, Wentao; Dong, Jiajia; Li, Suhua; Liu, Yu; Wang, Yujia; Yoon, Leonard; Wu, Peng; Sharpless, K Barry; Kelly, Jeffery W

2016-01-26

Tyrosine O-sulfation is a common protein post-translational modification that regulates many biological processes, including leukocyte adhesion and chemotaxis. Many peptides with therapeutic potential contain one or more sulfotyrosine residues. We report a one-step synthesis for Fmoc-fluorosulfated tyrosine. An efficient Fmoc-based solid-phase peptide synthetic strategy is then introduced for incorporating the fluorosulfated tyrosine residue into peptides of interest. Standard simultaneous peptide-resin cleavage and removal of the acid-labile side-chain protecting groups affords the crude peptides containing fluorosulfated tyrosine. Basic ethylene glycol, serving both as solvent and reactant, transforms the fluorosulfated tyrosine peptides into sulfotyrosine peptides in high yield. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dissipation-driven phase transitions in superconducting wires

NASA Astrophysics Data System (ADS)

Lobos, Alejandro; Iucci, Aníbal; Müller, Markus; Giamarchi, Thierry

2010-03-01

Narrow superconducting wires with diameter dξ0 (where ξ0 is the bulk superconducting coherence length) are quasi-1D systems in which fluctuations of the order parameter strongly affect low-temperature properties. Indeed, fluctuations cause the magnitude of the order parameter to temporarily vanish at some point along the wire, allowing its phase to slip by 2π, and to produce finite resistivity for all temperatures below Tc. In this work, we show that a weak coupling to a diffusive metallic film reinforces superconductivity in the wire through a quench of phase fluctuations. We analyze the effective phase-only action of the system by a perturbative renormalization-group and a self-consistent variational approach to obtain the critical points and phases at T=0. We predict a quantum phase transition towards a superconducting phase with long-range order as a function of the wire stiffness and coupling to the metal. Finally we discuss implications for the DC resistivity of the wire.

Further analytical study of hybrid rocket combustion

NASA Technical Reports Server (NTRS)

Hung, W. S. Y.; Chen, C. S.; Haviland, J. K.

1972-01-01

Analytical studies of the transient and steady-state combustion processes in a hybrid rocket system are discussed. The particular system chosen consists of a gaseous oxidizer flowing within a tube of solid fuel, resulting in a heterogeneous combustion. Finite rate chemical kinetics with appropriate reaction mechanisms were incorporated in the model. A temperature dependent Arrhenius type fuel surface regression rate equation was chosen for the current study. The governing mathematical equations employed for the reacting gas phase and for the solid phase are the general, two-dimensional, time-dependent conservation equations in a cylindrical coordinate system. Keeping the simplifying assumptions to a minimum, these basic equations were programmed for numerical computation, using two implicit finite-difference schemes, the Lax-Wendroff scheme for the gas phase, and, the Crank-Nicolson scheme for the solid phase.

Stability of Electrodeposition at Solid-Solid Interfaces and Implications for Metal Anodes

NASA Astrophysics Data System (ADS)

Ahmad, Zeeshan; Viswanathan, Venkatasubramanian

2017-08-01

We generalize the conditions for stable electrodeposition at isotropic solid-solid interfaces using a kinetic model which incorporates the effects of stresses and surface tension at the interface. We develop a stability diagram that shows two regimes of stability: a previously known pressure-driven mechanism and a new density-driven stability mechanism that is governed by the relative density of metal in the two phases. We show that inorganic solids and solid polymers generally do not lead to stable electrodeposition, and provide design guidelines for achieving stable electrodeposition.

Kinetics of transformation of deformation processed gold-matrix composite

NASA Astrophysics Data System (ADS)

Wongpreedee, Kageeporn

Gold matrix Ḏeformation-processed M&barbelow;etal M&barbelow;etal C&barbelow;omposites (DMMC) have been developed that have better strength and conductivity than conventional gold alloys. However, DMMC possess metastable two-phase microstructures, and their strength and conductivity decrease after prolonged exposure to elevated temperatures. The kinetics of the transformation from the metastable two-phase microstructure to the equilibrium single-phase solid solution is of interest. This document describes a study of the elevated temperature stability of Au DMMC's and the relationship between microstructure and resistivity of three compositions: Au-7 vol %Ag, Au-14 vol %Ag, and Au-vol 7%Pt. DMMC samples were prepared by a powder metallurgy technique and mechanical processes. The smallest final diameter of these wires was 120 mum. Avrami and Arrhenius relations were used to evaluate the kinetic transformation. The extensive deformation used to produce these composites reshaped the initially equi-axed powder particles into a nanofilamentary composite. Electrical resistivity measurements were used to determine the degree of transformation from the initial metastable nano-filamentary composite to the equilibrium solid solution condition. These measurements indicated that this transformation in Au-14 at%Ag, Au-7 at %Ag Au and Au-7 at %Pt DMMC wires proceeded with activation energies of 141, 156, and 167 kJ/mol, respectively. It is thought that these empirically determined activation energies differ from those determined in single crystal, planar interface Au-Ag and Au-Pt diffusion couples due to chemical potential, surface curvature, and strain effects. The DMMC systems reach the equilibrium solid solution condition faster than single crystal, planar interface systems for two reasons: (1) far more defects (dislocations, grain boundaries, vacancies from non-conservative dislocation motion, etc.) are present in the Au-Ag and Au-Pt DMMC composites, and (2) the small radius of curvature of the Ag and Pt filaments increases the chemical potential for diffusion in the DMMC.

The Rheological Properties of Lipid Monolayers Modulate the Incorporation of l-Ascorbic Acid Alkyl Esters.

PubMed

Díaz, Yenisleidy de Las Mercedes Zulueta; Mottola, Milagro; Vico, Raquel V; Wilke, Natalia; Fanani, María Laura

2016-01-19

In this work, we tested the hypothesis that the incorporation of amphiphilic drugs into lipid membranes may be regulated by their rheological properties. For this purpose, two members of the l-ascorbic acid alkyl esters family (ASCn) were selected, ASC16 and ASC14, which have different rheological properties when organized at the air/water interface. They are lipophilic forms of vitamin C used in topical pharmacological preparations. The effect of the phase state of the host lipid membranes on ASCn incorporation was explored using Langmuir monolayers. Films of pure lipids with known phase states have been selected, showing liquid-expanded, liquid-condensed, and solid phases as well as pure cholesterol films in liquid-ordered state. We also tested ternary and quaternary mixed films that mimic the properties of cholesterol containing membranes and of the stratum corneum. The compressibility and shear properties of those monolayers were assessed in order to define its phase character. We found that the length of the acyl chain of the ASCn compounds induces differential changes in the rheological properties of the host membrane and subtly regulates the kinetics and extent of the penetration process. The capacity for ASCn uptake was found to depend on the phase state of the host film. The increase in surface pressure resultant after amphiphile incorporation appears to be a function of the capacity of the host membrane to incorporate such amphiphile as well as the rheological response of the film. Hence, monolayers that show a solid phase state responded with a larger surface pressure increase to the incorporation of a comparable amount of amphiphile than liquid-expanded ones. The cholesterol-containing films, including the mixture that mimics stratum corneum, allowed a very scarce ASCn uptake independently of the membrane diffusional properties. This suggests an important contribution of Cho on the maintenance of the barrier function of stratum corneum.

7 CFR 1755.701 - Scope.

Code of Federal Regulations, 2014 CFR

2014-01-01

...) The aerial service wires can be either copper coated steel reinforced or nonmetallic reinforced designs. (c) For the copper coated steel reinforced design, the reinforcing members are the conductors. (1) The conductors are solid copper-covered steel wires. (2) The wire structure is completed by insulating...

7 CFR 1755.701 - Scope.

Code of Federal Regulations, 2012 CFR

2012-01-01

...) The aerial service wires can be either copper coated steel reinforced or nonmetallic reinforced designs. (c) For the copper coated steel reinforced design, the reinforcing members are the conductors. (1) The conductors are solid copper-covered steel wires. (2) The wire structure is completed by insulating...

7 CFR 1755.701 - Scope.

Code of Federal Regulations, 2013 CFR

2013-01-01

...) The aerial service wires can be either copper coated steel reinforced or nonmetallic reinforced designs. (c) For the copper coated steel reinforced design, the reinforcing members are the conductors. (1) The conductors are solid copper-covered steel wires. (2) The wire structure is completed by insulating...

7 CFR 1755.370 - RUS specification for seven wire galvanized steel strand.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 11 2012-01-01 2012-01-01 false RUS specification for seven wire galvanized steel... steel strand. (a) RUS incorporates by reference ASTM A475-78, Standard Specification for Zinc-Coated Steel Wire Strand, issued May 1978. All seven wire galvanized steel strand purchased after April 1, 1990...

7 CFR 1755.370 - RUS specification for seven wire galvanized steel strand.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 11 2014-01-01 2014-01-01 false RUS specification for seven wire galvanized steel... steel strand. (a) RUS incorporates by reference ASTM A475-78, Standard Specification for Zinc-Coated Steel Wire Strand, issued May 1978. All seven wire galvanized steel strand purchased after April 1, 1990...

7 CFR 1755.370 - RUS specification for seven wire galvanized steel strand.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 11 2013-01-01 2013-01-01 false RUS specification for seven wire galvanized steel... steel strand. (a) RUS incorporates by reference ASTM A475-78, Standard Specification for Zinc-Coated Steel Wire Strand, issued May 1978. All seven wire galvanized steel strand purchased after April 1, 1990...

Method of fabricating a homogeneous wire of inter-metallic alloy

DOEpatents

Ohriner, Evan Keith; Blue, Craig Alan

2001-01-01

A method for fabricating a homogeneous wire of inter-metallic alloy comprising the steps of providing a base-metal wire bundle comprising a metal, an alloy or a combination thereof; working the wire bundle through at least one die to obtain a desired dimension and to form a precursor wire; and, controllably heating the precursor wire such that a portion of the wire will become liquid while simultaneously maintaining its desired shape, whereby substantial homogenization of the wire occurs in the liquid state and additional homogenization occurs in the solid state resulting in a homogenous alloy product.

Instability of the sliding Luttinger liquid

NASA Astrophysics Data System (ADS)

Fleurov, V.; Kagalovsky, V.; Lerner, I. V.; Yurkevich, I. V.

2018-05-01

We revise a phase diagram for the sliding Luttinger liquid (SLL) of coupled one-dimensional quantum wires packed in two- or three-dimensional arrays in the absence of a magnetic field. We analyse whether physically justifiable (reasonable) inter-wire interactions, i.e. either the screened Coulomb or ‘Coulomb-blockade’ type interactions, stabilise the SLL phase. Calculating the scaling dimensions of the most relevant perturbations (the inter-wire single-particle hybridisation, charge-density wave, and superconducting inter-wire couplings), we find that their combination always destroys the SLL phase for the repulsive intra-wire interaction. However, suppressing the inter-wire tunnelling of repulsive fermions (when the charge-density wave is the only remaining perturbation), one can observe a stability region emerging due to the inter-wire forward scattering interaction.

A three-dimensional phase field model for nanowire growth by the vapor-liquid-solid mechanism

NASA Astrophysics Data System (ADS)

Wang, Yanming; Ryu, Seunghwa; McIntyre, Paul C.; Cai, Wei

2014-07-01

We present a three-dimensional multi-phase field model for catalyzed nanowire (NW) growth by the vapor-liquid-solid (VLS) mechanism. The equation of motion contains both a Ginzburg-Landau term for deposition and a diffusion (Cahn-Hilliard) term for interface relaxation without deposition. Direct deposition from vapor to solid, which competes with NW crystal growth through the molten catalyst droplet, is suppressed by assigning a very small kinetic coefficient at the solid-vapor interface. The thermodynamic self-consistency of the model is demonstrated by its ability to reproduce the equilibrium contact angles at the VLS junction. The incorporation of orientation dependent gradient energy leads to faceting of the solid-liquid and solid-vapor interfaces. The model successfully captures the curved shape of the NW base and the Gibbs-Thomson effect on growth velocity.

Incorporating technetium in minerals and other solids: A review

NASA Astrophysics Data System (ADS)

Luksic, Steven A.; Riley, Brian J.; Schweiger, Michael; Hrma, Pavel

2015-11-01

Technetium (Tc) can be incorporated into a number of different solids including spinel, sodalite, rutile, tin dioxide, pyrochlore, perovskite, goethite, layered double hydroxides, cements, and alloys. Synthetic routes are possible for each of these phases, ranging from high-temperature ceramic sintering to ball-milling of constituent oxides. However, in practice, Tc has only been incorporated into solid materials by a limited number of the possible syntheses. A review of the diverse ways in which Tc-immobilizing materials can be made shows the wide range of options available. Special consideration is given to hypothetical application to the Hanford Tank Waste and Vitrification Plant, such as adding a Tc-bearing mineral to waste glass melter feed. A full survey of solid Tc waste forms, the common synthesis routes to those waste forms, and their potential for application to vitrification processes are presented. The use of tin dioxide or ferrite spinel precursors to reduce Tc(VII) out of solution and into a durable form are shown to be of especially high potential.

Life cycle assessment of the application of nanoclays in wire coating

NASA Astrophysics Data System (ADS)

Tellaetxe, A.; Blázquez, M.; Arteche, A.; Egizabal, A.; Ermini, V.; Rose, J.; Chaurand, P.; Unzueta, I.

2012-09-01

A life cycle assessment (LCA) is carried out to compare nanoclay-reinforced polymer wire coatings with conventional ones. While the conventional wire coatings contain standard halogen free retardants, in reinforced coatings, montmorillonite (nanoclay) is incorporated into electric cable linings as a rheological agent for an increased resistance to fire. In addition, a reduced load of standard halogen free retardants is obtained. The synergistic effect of the montmorillonite on traditional flame retardant additives (by the formation of a three-dimensional char network) can lead to a revolution in wire production. The application of nanoclays contributes also to anti-dripping effect and flexibility increase [1]. Some producers have already started commercializing wire with nanotechnology-based coating; in the short term the use of nanoclay in wire coating production will probably reach a significant market share replacing traditional formulations. The main aim of this study is to compare the environmental impacts along the life cycle of a traditional wire coating (mineral flame retardants like ATH or MDH in a polymer matrix) with the nanoclay-reinforced wire coating, where the montmorillonite replaces a low percentage of the mineral flame retardant. The system boundaries of the study include the following unit processes: nanoclay production, thermoplastic material and mineral flame retardants production, cable coating manufacturing by extrusion and different end of life scenarios (recycling, incineration and landfill disposal). Whereas nanoreinforced composites have shown and increased fire retardance, the addition of nanomaterials seems to have no significant relevance in the environmental assessment. However, the lack of nano-specific characterization factors for nanomaterials and emission rates associated to the different life cycle stages -mainly in the extrusion and use phase, where accidental combustions can take place- still remains a challenge for realistic life cycle assessment modelling.

Flywheel system using wire-wound rotor

DOEpatents

Chiao, Edward Young; Bender, Donald Arthur; Means, Andrew E.; Snyder, Philip K.

2016-06-07

A flywheel is described having a rotor constructed of wire wound onto a central form. The wire is prestressed, thus mitigating stresses that occur during operation. In another aspect, the flywheel incorporates a low-loss motor using electrically non-conducting permanent magnets.

Decomposition of poly(amide-imide) film enameled on solid copper wire using atmospheric pressure non-equilibrium plasma.

PubMed

Sugiyama, Kazuo; Suzuki, Katsunori; Kuwasima, Shusuke; Aoki, Yosuke; Yajima, Tatsuhiko

2009-01-01

The decomposition of a poly(amide-imide) thin film coated on a solid copper wire was attempted using atmospheric pressure non-equilibrium plasma. The plasma was produced by applying microwave power to an electrically conductive material in a gas mixture of argon, oxygen, and hydrogen. The poly(amide-imide) thin film was easily decomposed by argon-oxygen mixed gas plasma and an oxidized copper surface was obtained. The reduction of the oxidized surface with argon-hydrogen mixed gas plasma rapidly yielded a metallic copper surface. A continuous plasma heat-treatment process using a combination of both the argon-oxygen plasma and argon-hydrogen plasma was found to be suitable for the decomposition of the poly(amide-imide) thin film coated on the solid copper wire.

Modified Process Reduces Porosity when Soldering in Reduced Gravity Environments

NASA Technical Reports Server (NTRS)

Watson, Kevin; Struk, Peter; Pettegrew, Richard; Downs, Robert; Haylett, Daniel

2012-01-01

A modified process yields lower levels of internal porosity for solder joints produced in reduced-gravity environments. The process incorporates both alternative materials and a modified procedure. The process provides the necessary cleaning action to enable effective bonding of the applied solder alloy with the materials to be joined. The modified process incorporates a commercially available liquid flux that is applied to the solder joint before heating with the soldering iron. It is subsequently heated with the soldering iron to activate the cleaning action of the flux and to evaporate most of the flux, followed by application of solder alloy in the form of commercially available solid solder wire (containing no flux). Continued heating ensures adequate flow of the solder alloy around and onto the materials to be joined. The final step is withdrawal of the soldering iron to allow alloy solidification and cooling of the solder joint.

A Simple Experiment in the Separation of a Solid-Phase Mixture and Infrared Spectroscopy for Introductory Chemistry

ERIC Educational Resources Information Center

Szalay, Paul S.

2008-01-01

This experiment was developed as a means of incorporating instrumental analyses into an introductory chemistry laboratory. A two-component solid mixture of caffeine and ibuprofen is separated through a series of solution extractions and precipitation and their relative amounts measured. These compounds were chosen because the combination of…

Preparation of C18 composite solid-phase microextraction fiber and its application to the determination of organochlorine pesticides in water samples.

PubMed

Li, Siyan; Lu, Chengwei; Zhu, Fang; Jiang, Ruifen; Ouyang, Gangfeng

2015-05-11

In this work, a C18 composite solid-phase microextraction (SPME) fiber was prepared with a new method and applied to the analysis of organochlorine pesticides (OCPs) in water sample. A stainless steel wire (o.d. 127 μm) was used as the substrate, and a mixture of the C18 particle (3.5 μm) and the 184 silicone was used as the coating material. During the process of fiber preparation, a section of capillary column was used to fix the mixture onto the stainless steel wire and to ensure the constant of coating thickness. The prepared fiber showed excellent thermal stability and solvent resistance. By coupling with gas chromatography-mass spectrometry (GC-MS), the fiber exhibited wide linearity (2-500 ng L(-1)) and good sensitivity for the determination of six OCPs in water samples, the OCPs tested included hexachlorobezene, trans-chlordane, cis-chlordane, o,p-DDT, p,p-DDT and mirex. Not only the extraction performance of the newly prepared fiber was more than seven times higher than those of commercial fibers, the limits of detections (LODs) (0.059-0.151 ng L(-1)) for OCPs achieved under optimized conditions were also lower than those of reported SPME methods. The fiber was successfully applied to the determination of OCPs in real water samples by using developed SPME-GC-MS method. Copyright © 2015 Elsevier B.V. All rights reserved.

Gas chromatographic detection of some nitro explosive compounds in soil samples after solid-phase microextraction with carbon ceramic copper nanoparticle fibers.

PubMed

Farhadi, Khalil; Bochani, Shayesteh; Hatami, Mehdi; Molaei, Rahim; Pirkharrati, Hossein

2014-07-01

In this research, a new solid-phase microextraction fiber based on carbon ceramic composites with copper nanoparticles followed by gas chromatography with flame ionization detection was applied for the extraction and determination of some nitro explosive compounds in soil samples. The proposed method provides an overview of trends related to synthesis of solid-phase microextraction sorbents and their applications in preconcentration and determination of nitro explosives. The sorbents were prepared by mixing of copper nanoparticles with a ceramic composite produced by mixture of methyltrimethoxysilane, graphite, methanol, and hydrochloric acid. The prepared sorbents were coated on copper wires by dip-coating method. The prepared nanocomposites were evaluated statistically and provided better limits of detection than the pure carbon ceramic. The limit of detection of the proposed method was 0.6 μg/g with a linear response over the concentration range of 2-160 μg/g and square of correlation coefficient >0.992. The new proposed fiber has been demonstrated to be a suitable, inexpensive, and sensitive candidate for extraction of nitro explosive compounds in contaminated soil samples. The constructed fiber can be used more than 100 times without the need for surface generation. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Preparation and application of a polythiophene solid-phase microextraction fiber for the determination of endocrine-disruptor pesticides in well waters.

PubMed

Pelit, Levent; Dizdaş, Tuğberk Nail

2013-10-01

A robust solid-phase microextraction fiber was fabricated by electropolymerization of thiophene on a stainless steel wire. This fiber was applied for the determination of endocrine-disruptor pesticides, namely, chlorpyrifos, penconazole, procymidone, bromopropylate, and λ-cyhalothrin in well waters by a headspace solid-phase microextraction procedure. Operational parameters, namely, pH, sample volume, adsorption temperature and time, desorption temperature, stirring rate, and salt amount were optimized as 7.0, 8 mL, 70°C and 20 min, 250°C, 600 rpm, and 0.3 g/mL, respectively. The separation power of GC was coupled with the excellent sensitivity of the developed fiber enabling us to determine pesticide mixtures simultaneously in a ng/mL range. The LOD was in the range of 0.02-0.64 ng/mL. The method was successfully applied for the selective and sensitive determination of target pesticides in well water samples with acceptable recovery values (92-110%). The polythiophene fiber gives satisfactory results compared with commercial fibers. Commonly used pesticides with different polarities were chosen as representative compounds to search the applicability of the fiber for well water analysis collected from vineyards. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A novel poly(3,4-ethylenedioxythiophene)-ionic liquid composite coating for the headspace solid-phase microextraction and gas chromatography determination of several alcohols in soft drinks.

PubMed

Wu, Mian; Zhang, Haibo; Zhao, Faqiong; Zeng, Baizhao

2014-11-19

A novel poly(3,4-ethylenedioxythiophene)-ionic liquid (i.e., 1-hydroxyethyl-3-methyl imidazolium-bis[(trifluoromethyl)sulfonyl]imide) composite film was electrodeposited on a Pt wire for headspace solid-phase microextraction. The film showed nodular structure and had large specific surface. In addition, it displayed high thermal stability (up to 300°C) and durable property (could be used for more than 200 times). Coupled with gas chromatography-flame ionization detection, the resulting fiber was applied to the headspace solid-phase microextraction and determination of several alcohols (i.e., linalool, nonanol, terpineol, geraniol, decanol and dodecanol). It presented higher extraction capability in comparison with the poly(3,4-ethylenedioxythiophene) and commercial polydimethylsiloxane/divinylbenzene fiber. Under the optimized conditions, the linear ranges exceeded three magnitudes with correlation coefficients above 0.9952 and the low limits of detection were 34.2-81.3ng L(-1). For different alcohols the repeatabilities (defined as RSD) were <5.8% and <7.8% for single fiber (n=5) and fiber-to-fiber (n=4), respectively. The proposed method was applied to the determination of these alcohols in real samples with acceptable recoveries from 81.1% to 106.6%. Copyright © 2014 Elsevier B.V. All rights reserved.

Electron transport in stretched monoatomic gold wires.

PubMed

Grigoriev, A; Skorodumova, N V; Simak, S I; Wendin, G; Johansson, B; Ahuja, R

2006-12-08

The conductance of monoatomic gold wires containing 3-7 gold atoms has been obtained from ab initio calculations. The transmission is found to vary significantly depending on the wire stretching and the number of incorporated atoms. Such oscillations are determined by the electronic structure of the one-dimensional (1D) part of the wire between the contacts. Our results indicate that the conductivity of 1D wires can be suppressed without breaking the contact.

Properties of a Variable-Delay Polarization Modulator

NASA Technical Reports Server (NTRS)

Chuss, David T.; Wollack, Edward J.; Henry, Ross; Hui, Howard; Juarez, Aaron J.; Krenjy, Megan; Moseley, Harvey; Novak, Giles

2011-01-01

We investigate the polarization modulation properties of a variable-delay polarization modulator (VPM). The VPM modulates polarization via a variable separation between a polarizing grid and a parallel mirror. We find that in the limit where the wavelength is much larger than the diameter of the metal wires that comprise the grid, the phase delay derived from the geometric separation between the mirror and the grid is sufficient to characterize the device. However, outside of this range, additional parameters describing the polarizing grid geometry must be included to fully characterize the modulator response. In this paper, we report test results of a VPM at wavelengths of 350 micron and 3 mm. Electromagnetic simulations of wire grid polarizers were performed and are summarized using a simple circuit model that incorporates the loss and polarization properties of the device.

Mechanical and Metallurgical Properties of Various Nickel-Titanium Rotary Instruments

PubMed Central

Shim, Kyu-Sang; Oh, Soram; Kim, Yu-Chan; Jee, Kwang-Koo

2017-01-01

The aim of this study was to investigate the effect of thermomechanical treatment on mechanical and metallurgical properties of nickel-titanium (NiTi) rotary instruments. Eight kinds of NiTi rotary instruments with sizes of ISO #25 were selected: ProFile, K3, and One Shape for the conventional alloy; ProTaper NEXT, Reciproc, and WaveOne for the M-wire alloy; HyFlex CM for the controlled memory- (CM-) wire; and TF for the R-phase alloy. Torsional fracture and cyclic fatigue fracture tests were performed. Products underwent a differential scanning calorimetry (DSC) analysis. The CM-wire and R-phase groups had the lowest elastic modulus, followed by the M-wire group. The maximum torque of the M-wire instrument was comparable to that of a conventional instrument, while those of the CM-wire and R-phase instruments were lower. The angular displacement at failure (ADF) for the CM-wire and R-phase instruments was higher than that of conventional instruments, and ADF of the M-wire instruments was lower. The cyclic fatigue resistance of the thermomechanically treated NiTi instruments was higher. DSC plots revealed that NiTi instruments made with the conventional alloy were primarily composed of austenite at room temperature; stable martensite and R-phase were found in thermomechanically treated instruments. PMID:29318149

Crystal-Phase Quantum Wires: One-Dimensional Heterostructures with Atomically Flat Interfaces.

PubMed

Corfdir, Pierre; Li, Hong; Marquardt, Oliver; Gao, Guanhui; Molas, Maciej R; Zettler, Johannes K; van Treeck, David; Flissikowski, Timur; Potemski, Marek; Draxl, Claudia; Trampert, Achim; Fernández-Garrido, Sergio; Grahn, Holger T; Brandt, Oliver

2018-01-10

In semiconductor quantum-wire heterostructures, interface roughness leads to exciton localization and to a radiative decay rate much smaller than that expected for structures with flat interfaces. Here, we uncover the electronic and optical properties of the one-dimensional extended defects that form at the intersection between stacking faults and inversion domain boundaries in GaN nanowires. We show that they act as crystal-phase quantum wires, a novel one-dimensional quantum system with atomically flat interfaces. These quantum wires efficiently capture excitons whose radiative decay gives rise to an optical doublet at 3.36 eV at 4.2 K. The binding energy of excitons confined in crystal-phase quantum wires is measured to be more than twice larger than that of the bulk. As a result of their unprecedented interface quality, these crystal-phase quantum wires constitute a model system for the study of one-dimensional excitons.

Dynamical analysis of surface-insulated planar wire array Z-pinches

NASA Astrophysics Data System (ADS)

Li, Yang; Sheng, Liang; Hei, Dongwei; Li, Xingwen; Zhang, Jinhai; Li, Mo; Qiu, Aici

2018-05-01

The ablation and implosion dynamics of planar wire array Z-pinches with and without surface insulation are compared and discussed in this paper. This paper first presents a phenomenological model named the ablation and cascade snowplow implosion (ACSI) model, which accounts for the ablation and implosion phases of a planar wire array Z-pinch in a single simulation. The comparison between experimental data and simulation results shows that the ACSI model could give a fairly good description about the dynamical characteristics of planar wire array Z-pinches. Surface insulation introduces notable differences in the ablation phase of planar wire array Z-pinches. The ablation phase is divided into two stages: insulation layer ablation and tungsten wire ablation. The two-stage ablation process of insulated wires is simulated in the ACSI model by updating the formulas describing the ablation process.

77 FR 50160 - Steel Wire Garment Hangers From Taiwan and Vietnam; Scheduling of the Final Phase of...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-20

...)] Steel Wire Garment Hangers From Taiwan and Vietnam; Scheduling of the Final Phase of Countervailing Duty... States is materially retarded, by reason of subsidized imports from Taiwan of steel wire garment hangers and less- than-fair-value imports from Taiwan and Vietnam of steel wire garment hangers, provided for...

Si Wire-Array Solar Cells

NASA Astrophysics Data System (ADS)

Boettcher, Shannon

2010-03-01

Micron-scale Si wire arrays are three-dimensional photovoltaic absorbers that enable orthogonalization of light absorption and carrier collection and hence allow for the utilization of relatively impure Si in efficient solar cell designs. The wire arrays are grown by a vapor-liquid-solid-catalyzed process on a crystalline (111) Si wafer lithographically patterned with an array of metal catalyst particles. Following growth, such arrays can be embedded in polymethyldisiloxane (PDMS) and then peeled from the template growth substrate. The result is an unusual photovoltaic material: a flexible, bendable, wafer-thickness crystalline Si absorber. In this paper I will describe: 1. the growth of high-quality Si wires with controllable doping and the evaluation of their photovoltaic energy-conversion performance using a test electrolyte that forms a rectifying conformal semiconductor-liquid contact 2. the observation of enhanced absorption in wire arrays exceeding the conventional light trapping limits for planar Si cells of equivalent material thickness and 3. single-wire and large-area solid-state Si wire-array solar cell results obtained to date with directions for future cell designs based on optical and device physics. In collaboration with Michael Kelzenberg, Morgan Putnam, Joshua Spurgeon, Daniel Turner-Evans, Emily Warren, Nathan Lewis, and Harry Atwater, California Institute of Technology.

Self-Catalyzed Growth and Characterization of In(As)P Nanowires on InP(111)B Using Metal-Organic Chemical Vapor Deposition.

PubMed

Park, Jeung Hun; Pozuelo, Marta; Setiawan, Bunga P D; Chung, Choong-Heui

2016-12-01

We report the growth of vertical <111>-oriented InAs x P1-x (0.11 ≤ x ≤ 0.27) nanowires via metal-organic chemical vapor deposition in the presence of indium droplets as catalysts on InP(111)B substrates at 375 °C. Trimethylindium, tertiarybutylphosphine, and tertiarybutylarsine are used as the precursors, corresponding to P/In and As/In molar ratios of 29 and 0.01, respectively. The as-grown nanowire growth morphologies, crystallinity, composition, and optical characteristics are determined using a combination of scanning and transmission electron microscopies, electron diffraction, and X-ray photoelectron, energy dispersive X-ray, and Raman spectroscopies. We find that the InAs x P1-x nanowires are tapered with narrow tops, wider bases, and In-rich In-As alloy tips, characteristic of vapor-liquid-solid process. The wires exhibit a mixture of zinc blende and wurtzite crystal structures and a high density of structural defects such as stacking faults and twins. Our results suggest that the incorporation of As into InP wires decreases with increasing substrate temperature. The Raman spectra obtained from the In(As)P nanowires reveal a red-shift and lower intensity of longitudinal optical mode relative to both InP nanowires and InP(111)B bulk, due to the incorporation of As into the InP matrix.

Non-nucleoside building blocks for copper-assisted and copper-free click chemistry for the efficient synthesis of RNA conjugates.

PubMed

Jayaprakash, K N; Peng, Chang Geng; Butler, David; Varghese, Jos P; Maier, Martin A; Rajeev, Kallanthottathil G; Manoharan, Muthiah

2010-12-03

Novel non-nucleoside alkyne monomers compatible with oligonucleotide synthesis were designed, synthesized, and efficiently incorporated into RNA and RNA analogues during solid-phase synthesis. These modifications allowed site-specific conjugation of ligands to the RNA oligonucleotides through copper-assisted (CuAAC) and copper-free strain-promoted azide-alkyne cycloaddition (SPAAC) reactions. The SPAAC click reactions of cyclooctyne-oligonucleotides with various classes of azido-functionalized ligands in solution phase and on solid phase were efficient and quantitative and occurred under mild reaction conditions. The SPAAC reaction provides a method for the synthesis of oligonucleotide-ligand conjugates uncontaminated with copper ions.

Project Description and Publications List for UAH CMMR

NASA Technical Reports Server (NTRS)

Kaukler, William F.

1999-01-01

This research combines a state of the art X-ray Transmission Microscope, XTM, with a specially designed x-ray transparent horizontal Bridgman furnace to image (with resolutions up to 3 micrometers) the solidification of metal alloys in real-time. The objective is to obtain real-time dynamic data to provide direct measure of the solute profile in the liquid, phase coalescence and growth in the liquid, and the detailed interface morphology (e,g., dendrites and cells) during solidification. We are also enhancing the XTM data with precise solid-liquid interfacial temperature and the thermal gradient measurement techniques, and working on the application of this technology to the study of the fundamentals of solidification in microgravity. Over the last several years we have successfully imaged in real-time: interfacial-morphologies, phase growth, coalescence, incorporation of phases into the growing interface, and the solute boundary layer in the liquid at the solid-liquid interface. We have also measured true local growth rates and can evaluate segregation structures in the solid. Interfacial undercoolings are being measured either with a special Seebeck furnace or with micro-thermocouple arrays we are developing. These later techniques are presently being incorporated with the XTM furnace. This last year emphasized the investigation of the solute layer in the melt during solidification. Methods were developed to quantify the solute concentrations using x-ray absorption and to compare to predictions from simulations. In addition, work is being completed on a brass-board portable XTM that incorporates a vertical Bridgman furnace.

Investigation of the automated solid-phase synthesis of a 38mer peptide with difficult sequence pattern under different synthesis strategies.

PubMed

Winkler, Dirk F H; Tian, Kerry

2015-04-01

Difficult peptides are a constant challenge in solid-phase peptide synthesis. In particular, hydroxyl amino acids such as serine can cause severe breakdowns in coupling yields even several amino acids after the insertion of the critical amino acid. This paper investigates several methods of improving synthesis yields of difficult peptides including the use of different resins, activators and the incorporation of a structure-breaking pseudoproline dipeptide building block both alone and in combination with each other.

40 CFR 63.3890 - What emission limits must I meet?

Code of Federal Regulations, 2010 CFR

2010-07-01

... compliance period. (3) For each new magnet wire coating affected source, limit organic HAP emissions to no...) coating solids used during each 12-month compliance period. (3) For each existing magnet wire coating.... (1) If the general use or magnet wire surface coating operations subject to only one of the emission...

Hydrothermal carbonization of food waste for nutrient recovery and reuse.

PubMed

Idowu, Ifeolu; Li, Liang; Flora, Joseph R V; Pellechia, Perry J; Darko, Samuel A; Ro, Kyoung S; Berge, Nicole D

2017-11-01

Food waste represents a rather large and currently underutilized source of potentially available and reusable nutrients. Laboratory-scale experiments evaluating the hydrothermal carbonization of food wastes collected from restaurants were conducted to understand how changes in feedstock composition and carbonization process conditions influence primary and secondary nutrient fate. Results from this work indicate that at all evaluated reaction times and temperatures, the majority of nitrogen, calcium, and magnesium remain integrated within the solid-phase, while the majority of potassium and sodium reside in the liquid-phase. The fate of phosphorus is dependent on reaction times and temperatures, with solid-phase integration increasing with higher reaction temperature and longer time. A series of leaching experiments to determine potential solid-phase nutrient availability were also conducted and indicate that, at least in the short term, nitrogen release from the solids is small, while almost all of the phosphorus present in the solids produced from carbonizing at 225 and 250°C is released. At a reaction temperature of 275°C, smaller fractions of the solid-phase total phosphorus are released as reaction times increase, likely due to increased solids incorporation. Using these data, it is estimated that up to 0.96% and 2.30% of nitrogen and phosphorus-based fertilizers, respectively, in the US can be replaced by the nutrients integrated within hydrochar and liquid-phases generated from the carbonization of currently landfilled food wastes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Steady-state analysis of a faulted three-phase four-wire system supplying induction motors with neutrals connected and other single-phase line-to-neutral loads

NASA Technical Reports Server (NTRS)

Wood, M. E.

1980-01-01

Four wire Wye connected ac power systems exhibit peculiar steady state fault characteristics when the fourth wire of three phase induction motors is connected. The loss of one phase of power source due to a series or shunt fault results in currents higher than anticipated on the remaining two phases. A theoretical approach to compute the fault currents and voltages is developed. A FORTRAN program is included in the appendix.

Polarization of the photoluminescence of quantum dots incorporated into quantum wires

DOE Office of Scientific and Technical Information (OSTI.GOV)

Platonov, A. V., E-mail: alexei.platonov@mail.ioffe.ru; Kochereshko, V. P.; Kats, V. N.

The photoluminescence spectra of individual quantum dots incorporated into a quantum wire are studied. From the behavior of the spectra in a magnetic field, it is possible to estimate the exciton binding energy in a quantum dot incorporated into a quantum wire. It is found that the exciton photoluminescence signal emitted from a quantum dot along the direction of the nanowire axis is linearly polarized. At the same time, the photoluminescence signal propagating in the direction orthogonal to the nanowire axis is practically unpolarized. The experimentally observed effect is attributed to the nonaxial arrangement of the dot in the wiremore » under conditions of a huge increase in the exciton binding energy due to the effect of the image potential on the exciton.« less

Space cryogenics components based on the thermomechanical effect - Vapor-liquid phase separation

NASA Technical Reports Server (NTRS)

Yuan, S. W. K.; Frederking, T. H. K.

1989-01-01

Applications of the thermomechanical effect has been qualified including incorporation in large-scale space systems in the area of vapor-liquid phase separation (VLPS). The theory of the porous-plug phase separator is developed for the limit of a high thermal impedance of the solid-state grains. Extensions of the theory of nonlinear turbulent flow are presented based on experimental results.

Spin-dependent quantum transport in nanoscaled geometries

NASA Astrophysics Data System (ADS)

Heremans, Jean J.

2011-10-01

We discuss experiments where the spin degree of freedom leads to quantum interference phenomena in the solid-state. Under spin-orbit interactions (SOI), spin rotation modifies weak-localization to weak anti-localization (WAL). WAL's sensitivity to spin- and phase coherence leads to its use in determining the spin coherence lengths Ls in materials, of importance moreover in spintronics. Using WAL we measure the dependence of Ls on the wire width w in narrow nanolithographic ballistic InSb wires, ballistic InAs wires, and diffusive Bi wires with surface states with Rashba-like SOI. In all three systems we find that Ls increases with decreasing w. While theory predicts the increase for diffusive wires with linear (Rashba) SOI, we experimentally conclude that the increase in Ls under dimensional confinement may be more universal, with consequences for various applications. Further, in mesoscopic ring geometries on an InAs/AlGaSb 2D electron system (2DES) we observe both Aharonov-Bohm oscillations due to spatial quantum interference, and Altshuler-Aronov-Spivak oscillations due to time-reversed paths. A transport formalism describing quantum coherent networks including ballistic transport and SOI allows a comparison of spin- and phase coherence lengths extracted for such spatial- and temporal-loop quantum interference phenomena. We further applied WAL to study the magnetic interactions between a 2DES at the surface of InAs and local magnetic moments on the surface from rare earth (RE) ions (Gd3+, Ho3+, and Sm3+). The magnetic spin-flip rate carries information about magnetic interactions. Results indicate that the heavy RE ions increase the SOI scattering rate and the spin-flip rate, the latter indicating magnetic interactions. Moreover Ho3+ on InAs yields a spin-flip rate with an unusual power 1/2 temperature dependence, possibly characteristic of a Kondo system. We acknowledge funding from DOE (DE-FG02-08ER46532).

The melting and solidification of nanowires

NASA Astrophysics Data System (ADS)

Florio, B. J.; Myers, T. G.

2016-06-01

A mathematical model is developed to describe the melting of nanowires. The first section of the paper deals with a standard theoretical situation, where the wire melts due to a fixed boundary temperature. This analysis allows us to compare with existing results for the phase change of nanospheres. The equivalent solidification problem is also examined. This shows that solidification is a faster process than melting; this is because the energy transfer occurs primarily through the solid rather than the liquid which is a poorer conductor of heat. This effect competes with the energy required to create new solid surface which acts to slow down the process, but overall conduction dominates. In the second section, we consider a more physically realistic boundary condition, where the phase change occurs due to a heat flux from surrounding material. This removes the singularity in initial melt velocity predicted in previous models of nanoparticle melting. It is shown that even with the highest possible flux the melting time is significantly slower than with a fixed boundary temperature condition.

Electrochemical preparation of composite polyaniline coating and its application in the determination of bisphenol A, 4-n-nonylphenol, 4-tert-octylphenol using direct solid phase microextraction coupled with high performance liquid chromatography.

PubMed

Huang, Minjia; Jiang, Guibin; Cai, Yaqi

2005-11-01

For SPME-HPLC, metal wires with better mechanical strength are preferred over the fused silica fibers. In this article, a novel composite polyaniline (CPANI) doped with PEG and polydimethylsiloxane coating (CPANI fiber) was prepared on a stainless steel wire by a three-electrode system: the fiber was used as the work electrode, a calomel electrode and a platinum electrode were used as the reference and the counter electrodes, respectively. To evaluate the new CPANI coating, the coating was used to extract three kinds of phenols (bisphenol A, 4-n-nonylphenol, and 4-tert-octylphenol) in water samples by direct-SPME mode and then desorbed in commercial SPME-HPLC interface to separation. The extraction procedure was also optimized. Five real water samples were investigated. Good recoveries were gained when environmental samples were analyzed.

A uniaxial constitutive model for superelastic NiTi SMA including R-phase and martensite transformations and thermal effects

NASA Astrophysics Data System (ADS)

Helbert, Guillaume; Saint-Sulpice, Luc; Arbab Chirani, Shabnam; Dieng, Lamine; Lecompte, Thibaut; Calloch, Sylvain; Pilvin, Philippe

2017-02-01

The well-known martensitic transformation is not always the unique solid-solid phase change in NiTi shape memory alloys (SMA). For this material, R-phase can occur from both austenite and martensite. In some applications, macroscopic strain of the material can be limited to 2%. In these cases, R-phase contribution can not be neglected anymore when compared with martensite. Furthermore, different thermomechanical couplings have to be taken into account to carefully predict strain rate effects and to better describe application conditions. In this paper, a new model taking into account various phase transformations with thermomechanical couplings is presented. This model is based on several transformation criteria. In most applications, SMA are used as wires, submitted to tensile-tensile loadings, in the superelasticity working range. Consequently, a uniaxial reduction of the model is presented for its simplicity. A thermodynamic framework is proposed. It enables to describe the internal variables evolution laws. The simple and fast identification process of model parameters is briefly presented. To verify the validity of the proposed model, simulation results are compared with experimental ones. The influences of testing temperature and strain amplitude on the material behavior is discussed. The damping capacity is also studied, using an energy-based criterion.

A Reactive-Heat-Pipe for Combined Heat Generation and Transport

DTIC Science & Technology

1977-12-01

The Lennard - Jones potential parameters a and F-1 can be found in Ar Ar Table 2.3 of Reference [26]. They are a Ar =3.542 A ~Ar -=93.3 K The above...Specific Heat Ratio Wire Spacing of Screen S Volume Fraction of Solid Phase in Wick or Lennard Jones Force Constant e’ Wick Void Fraction 1Viscusity p...Density a Surface Tension G Condensation Coefficient c e Evaporation Coefficient*e U Lennard - Jones Force Constant Subscripts A Position A in Figure 13 Ar

Layered double hydroxide films on nanoporous anodic aluminum oxide/aluminum wire: a new fiber for rapid analysis of Origanum vulgare essential oils.

PubMed

Piryaei, Marzieh

2018-01-01

Zn/Al layered double hydroxide (LDH) films were fabricated in situ with anodic aluminium oxide aluminium as both the substrate and the sole aluminium source by means of urea hydrolysis. Headspace solid phase microextraction using LDH fibre in combination with capillary GC-MS was utilised as a monitoring technique for the collection and detection of the volatile compounds of Origanum vulgare. Experimental parameters, including the sample weight, microwave power, extraction time and humidity effect, were examined and optimised.

Electron microscopy investigation of gallium oxide micro/nanowire structures synthesized via vapor phase growth.

PubMed

Wang, Y; Xu, J; Wang, R M; Yu, D P

2004-01-01

Large-scale micro/nanosized Ga(2)O(3) structures were synthesized via a simple vapor p9hase growth method. The morphology of the as-grown structures varied from aligned arrays of smooth nano/microscale wires to composite and complex microdendrites. We present evidence that the formation of the observed structure depends strongly on its position relative to the source materials (the concentration distribution) and on the growth temperature. A growth model is proposed, based on the vapor-solid (VS) mechanism, which can explain the observed morphologies.

Energy-Conversion Properties of Vapor-Liquid-Solid-Grown Silicon Wire-Array Photocathodes

NASA Astrophysics Data System (ADS)

Boettcher, Shannon W.; Spurgeon, Joshua M.; Putnam, Morgan C.; Warren, Emily L.; Turner-Evans, Daniel B.; Kelzenberg, Michael D.; Maiolo, James R.; Atwater, Harry A.; Lewis, Nathan S.

2010-01-01

Silicon wire arrays, though attractive materials for use in photovoltaics and as photocathodes for hydrogen generation, have to date exhibited poor performance. Using a copper-catalyzed, vapor-liquid-solid-growth process, SiCl4 and BCl3 were used to grow ordered arrays of crystalline p-type silicon (p-Si) microwires on p+-Si(111) substrates. When these wire arrays were used as photocathodes in contact with an aqueous methyl viologen2+/+ electrolyte, energy-conversion efficiencies of up to 3% were observed for monochromatic 808-nanometer light at fluxes comparable to solar illumination, despite an external quantum yield at short circuit of only 0.2. Internal quantum yields were at least 0.7, demonstrating that the measured photocurrents were limited by light absorption in the wire arrays, which filled only 4% of the incident optical plane in our test devices. The inherent performance of these wires thus conceptually allows the development of efficient photovoltaic and photoelectrochemical energy-conversion devices based on a radial junction platform.

Energy-conversion properties of vapor-liquid-solid-grown silicon wire-array photocathodes.

PubMed

Boettcher, Shannon W; Spurgeon, Joshua M; Putnam, Morgan C; Warren, Emily L; Turner-Evans, Daniel B; Kelzenberg, Michael D; Maiolo, James R; Atwater, Harry A; Lewis, Nathan S

2010-01-08

Silicon wire arrays, though attractive materials for use in photovoltaics and as photocathodes for hydrogen generation, have to date exhibited poor performance. Using a copper-catalyzed, vapor-liquid-solid-growth process, SiCl4 and BCl3 were used to grow ordered arrays of crystalline p-type silicon (p-Si) microwires on p+-Si(111) substrates. When these wire arrays were used as photocathodes in contact with an aqueous methyl viologen(2+/+) electrolyte, energy-conversion efficiencies of up to 3% were observed for monochromatic 808-nanometer light at fluxes comparable to solar illumination, despite an external quantum yield at short circuit of only 0.2. Internal quantum yields were at least 0.7, demonstrating that the measured photocurrents were limited by light absorption in the wire arrays, which filled only 4% of the incident optical plane in our test devices. The inherent performance of these wires thus conceptually allows the development of efficient photovoltaic and photoelectrochemical energy-conversion devices based on a radial junction platform.

Weld Wire Investigation Summary

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cunningham, M.A.

1999-03-22

After GTA welding reservoir A production/process prove-in assemblies, X-ray examination detected a lack of sidewall fusion. After examining several possible causes, it was determined that the weld wire filler metal was responsible, particularly the wire cleaning process. The final conclusion was that the filler wire must be abrasively cleaned in a particular manner to perform as required. The abrasive process was incorporated into the wire material specification, ensuring consistency for all reservoir GTA welding at AlliedSignal Federal Manufacturing and Technologies (FM and T).

Length-dependent structural stability of linear monatomic Cu wires

NASA Astrophysics Data System (ADS)

Singh, Gurvinder; Kumar, Krishan; Singh, Baljinder; Moudgil, R. K.

2018-05-01

We present first-principle calculations based on density functional theory for the finite-length monatomic Cu atom linear wires. The structure and its stability with increasing wire length in terms of number of atoms (N) is determined. Interestingly, the bond length is found to exhibit an oscillatory structure (the so-called magic length phenomenon), with a qualitative change in oscillatory behavior as one moves from even N wire to odd N wire. The even N wires follow simple even-odd oscillations whereas odd N wires show a phase change at the half length of the wires. The stability of the wire structure, determined in terms of the wire formation energy, also contains even-odd oscillation as a function of wire length. However, the oscillations in formation energy reverse its phase after the wire length is increased beyond N=12. Our findings are seen to be qualitatively consistent with recent simulations for a similar class finite-length metal atom wires.

Most Wired 2006: measuring value.

PubMed

Solovy, Alden

2006-07-01

As the Most Wired hospitals incorporate information technology into their strategic plans, they combine a"balanced scorecard"approach with classic business analytics to measure how well IT delivers on their goals. To find out which organizations made this year's 100 Most Wired list, as well as those named in other survey categories, go to the foldout section.

The UT 19-channel DC SQUID based neuromagnetometer.

PubMed

ter Brake, H J; Flokstra, J; Jaszczuk, W; Stammis, R; van Ancum, G K; Martinez, A; Rogalla, H

1991-01-01

A 19-channel DC SQUID based neuromagnetometer is under construction at the University of Twente (UT). Except for the cryostat all elements of the system are developed at the UT. It comprises 19 wire-wound first-order gradiometers in a hexagonal configuration. The gradiometers are connected to planar DC SQUIDs fabricated with a Nb/Al, AlO kappa/Nb technology. For this connection we developed a method to bond a Nb wire to a Nb thin-film. The SQUIDs are placed in compartmentalised Nb modules. Further, external feedback is incorporated in order to eliminate cross talk between the gradiometers. The electronics basically consist of a phase-locked loop operating with a modulation frequency of 100 kHz. Between SQUID and preamplifier a small transformer is used to limit the noise contribution of the preamplifier. In the paper the overall system is described, and special attention is paid to the SQUID module (bonding, compartments, external-feedback setup, output transformer).

Physical and mechanical properties of a thermomechanically treated NiTi wire used in the manufacture of rotary endodontic instruments.

PubMed

Pereira, E S J; Peixoto, I F C; Viana, A C D; Oliveira, I I; Gonzalez, B M; Buono, V T L; Bahia, M G A

2012-05-01

To compare physical and mechanical properties of one conventional and one thermomechanically treated nickel-titanium (NiTi) wire used to manufacture rotary endodontic instruments. Two NiTi wires 1.0 mm in diameter were characterized; one of them, C-wire (CW), was processed in the conventional manner, and the other, termed M-Wire (MW), received an additional heat treatment according to the manufacturer. Chemical composition was determined by energy-dispersive X-ray spectroscopy, phase constitution by XRD and the transformation temperatures by DSC. Tensile loading/unloading tests and Vickers microhardness measurements were performed to assess the mechanical behaviour. Data were analysed using analysis of variance (α = 0.05). The two wires showed approximately the same chemical composition, close to the 1 : 1 atomic ratio, and the β-phase was the predominant phase present. B19' martensite and the R-phase were found in MW, in agreement with the higher transformation temperatures found in this wire compared with CW, whose transformation temperatures were below room temperature. Average Vickers microhardness values were similar for MW and CW (P = 0.91). The stress at the transformation plateau in the tensile load-unload curves was lower and more uniform in the M-Wire, which also showed the smallest stress hysteresis and apparent elastic modulus. The M-Wire had physical and mechanical properties that can render endodontic instruments more flexible and fatigue resistant than those made with conventionally processed NiTi wires. © 2011 International Endodontic Journal.

Multiplexed Colorimetric Solid-Phase Extraction

NASA Technical Reports Server (NTRS)

Gazda, Daniel B.; Fritz, James S.; Porter, Marc D.

2009-01-01

Multiplexed colorimetric solid-phase extraction (MC-SPE) is an extension of colorimetric solid-phase extraction (C-SPE) an analytical platform that combines colorimetric reagents, solid phase extraction, and diffuse reflectance spectroscopy to quantify trace analytes in water. In CSPE, analytes are extracted and complexed on the surface of an extraction membrane impregnated with a colorimetric reagent. The analytes are then quantified directly on the membrane surface using a handheld diffuse reflectance spectrophotometer. Importantly, the use of solid-phase extraction membranes as the matrix for impregnation of the colorimetric reagents creates a concentration factor that enables the detection of low concentrations of analytes in small sample volumes. In extending C-SPE to a multiplexed format, a filter holder that incorporates discrete analysis channels and a jig that facilitates the concurrent operation of multiple sample syringes have been designed, enabling the simultaneous determination of multiple analytes. Separate, single analyte membranes, placed in a readout cartridge create unique, analyte-specific addresses at the exit of each channel. Following sample exposure, the diffuse reflectance spectrum of each address is collected serially and the Kubelka-Munk function is used to quantify each water quality parameter via calibration curves. In a demonstration, MC-SPE was used to measure the pH of a sample and quantitate Ag(I) and Ni(II).

Two-phase anaerobic digestion of vegetable market waste fraction of municipal solid waste and development of improved technology for phase separation in two-phase reactor.

PubMed

Majhi, Bijoy Kumar; Jash, Tushar

2016-12-01

Biogas production from vegetable market waste (VMW) fraction of municipal solid waste (MSW) by two-phase anaerobic digestion system should be preferred over the single-stage reactors. This is because VMW undergoes rapid acidification leading to accumulation of volatile fatty acids and consequent low pH resulting in frequent failure of digesters. The weakest part in the two-phase anaerobic reactors was the techniques applied for solid-liquid phase separation of digestate in the first reactor where solubilization, hydrolysis and acidogenesis of solid organic waste occur. In this study, a two-phase reactor which consisted of a solid-phase reactor and a methane reactor was designed, built and operated with VMW fraction of Indian MSW. A robust type filter, which is unique in its implementation method, was developed and incorporated in the solid-phase reactor to separate the process liquid produced in the first reactor. Experiments were carried out to assess the long term performance of the two-phase reactor with respect to biogas production, volatile solids reduction, pH and number of occurrence of clogging in the filtering system or choking in the process liquid transfer line. The system performed well and was operated successfully without the occurrence of clogging or any other disruptions throughout. Biogas production of 0.86-0.889m 3 kg -1 VS, at OLR of 1.11-1.585kgm -3 d -1 , were obtained from vegetable market waste, which were higher than the results reported for similar substrates digested in two-phase reactors. The VS reduction was 82-86%. The two-phase anaerobic digestion system was demonstrated to be stable and suitable for the treatment of VMW fraction of MSW for energy generation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Preparation of microcapsules with self-microemulsifying core by a vibrating nozzle method.

PubMed

Homar, Miha; Suligoj, Dasa; Gasperlin, Mirjana

2007-02-01

Incorporation of drugs in self-microemulsifying systems (SMES) offers several advantages for their delivery, the main one being faster drug dissolution and absorption. Formulation of SMES in solid dosage forms can be difficult and, to date, most SMES are applied in liquid dosage form or soft gelatin capsules. This study has explored the incorporation of SMES in microcapsules, which could then be used for formulation of solid dosage forms. An Inotech IE-50 R encapsulator equipped with a concentric nozzle was used to produce alginate microcapsules with a self-microemulsifying core. Retention of the core phase was improved by optimization of encapsulator parameters and modification of the shell forming phase and hardening solution. The mean encapsulation efficiency of final batches was more than 87%, which resulted in 0.07% drug loading. It was demonstrated that production of microcapsules with a self-microemulsifying core is possible and that the process is stable and reproducible.

Synthesis of nanostructures in nanowires using sequential catalyst reactions

DOE PAGES

Panciera, F.; Chou, Y. -C.; Reuter, M. C.; ...

2015-07-13

Nanowire growth by the vapour–liquid–solid (VLS) process enables a high level of control over nanowire composition, diameter, growth direction, branching and kinking, periodic twinning, and crystal structure. The tremendous impact of VLS-grown nanowires is due to this structural versatility, generating applications ranging from solid-state lighting and single-photon sources to thermoelectric devices. Here, we show that the morphology of these nanostructures can be further tailored by using the liquid droplets that catalyse nanowire growth as a ‘mixing bowl’, in which growth materials are sequentially supplied to nucleate new phases. Growing within the liquid, these phases adopt the shape of faceted nanocrystalsmore » that are then incorporated into the nanowires by further growth. Furthermore, we demonstrate this concept by epitaxially incorporating metal-silicide nanocrystals into Si nanowires with defect-free interfaces, and discuss how this process can be generalized to create complex nanowire-based heterostructures.« less

Synthesis of nanostructures in nanowires using sequential catalyst reactions

PubMed Central

Panciera, F.; Chou, Y.-C.; Reuter, M.C.; Zakharov, D.; Stach, E.A.; Hofmann, S.; Ross, F.M.

2016-01-01

Nanowire growth by the vapor-liquid-solid process enables a high level of control over nanowire composition, diameter, growth direction, branching and kinking, periodic twinning, and crystal structure. The tremendous impact of VLS-grown nanowires is due to this structural versatility, generating applications ranging from solid state lighting and single photon sources to thermoelectric devices. Here we show that the morphology of these nanostructures can be further tailored by using the liquid droplets that catalyze nanowire growth as a “mixing bowl”, in which growth materials are sequentially supplied to nucleate new phases. Growing within the liquid, these phases adopt the shape of faceted nanocrystals that are then incorporated into the nanowires by further growth. We demonstrate this concept by epitaxially incorporating metal silicide nanocrystals into Si nanowires with defect-free interfaces, and discuss how this process can be generalized to create complex nanowire-based heterostructures. PMID:26168344

Powder metallurgy: Solid and liquid phase sintering of copper

NASA Technical Reports Server (NTRS)

Sheldon, Rex; Weiser, Martin W.

1993-01-01

Basic powder metallurgy (P/M) principles and techniques are presented in this laboratory experiment. A copper based system is used since it is relatively easy to work with and is commercially important. In addition to standard solid state sintering, small quantities of low melting metals such as tin, zinc, lead, and aluminum can be added to demonstrate liquid phase sintering and alloy formation. The Taguchi Method of experimental design was used to study the effect of particle size, pressing force, sintering temperature, and sintering time. These parameters can be easily changed to incorporate liquid phase sintering effects and some guidelines for such substitutions are presented. The experiment is typically carried out over a period of three weeks.

Investigating the Use of Ultrasound for Evaluating Aging Wiring Insulation

NASA Technical Reports Server (NTRS)

Madaras, Eric I.; Anastasi, Robert F.

2001-01-01

This paper reviews our initial efforts to investigate the use of ultrasound to evaluate wire insulation. Our initial model was a solid conductor with heat shrink tubing applied. In this model, various wave modes were identified. Subsequently, several aviation classes of wires (MIL-W- 81381, MIL-W-22759/34, and MIL-W-22759/87) were measured. The wires represented polyimide and ethylene-tetraflouroethylene insulations, and combinations of polyimide and flouropolymer plastics. Wire gages of 12, 16, and 20 AWG sizes were measured. Finally, samples of these wires were subjected to high temperatures for short periods of time to cause the insulation to degrade. Subsequent measurements indicated easily detectable changes.

Behaviour of Fe4O5-Mg2Fe2O5 solid solutions and their relation to coexisting Mg-Fe silicates and oxide phases

NASA Astrophysics Data System (ADS)

Uenver-Thiele, Laura; Woodland, Alan B.; Miyajima, Nobuyoshi; Ballaran, Tiziana Boffa; Frost, Daniel J.

2018-03-01

Experiments at high pressures and temperatures were carried out (1) to investigate the crystal-chemical behaviour of Fe4O5-Mg2Fe2O5 solid solutions and (2) to explore the phase relations involving (Mg,Fe)2Fe2O5 (denoted as O5-phase) and Mg-Fe silicates. Multi-anvil experiments were performed at 11-20 GPa and 1100-1600 °C using different starting compositions including two that were Si-bearing. In Si-free experiments the O5-phase coexists with Fe2O3, hp-(Mg,Fe)Fe2O4, (Mg,Fe)3Fe4O9 or an unquenchable phase of different stoichiometry. Si-bearing experiments yielded phase assemblages consisting of the O5-phase together with olivine, wadsleyite or ringwoodite, majoritic garnet or Fe3+-bearing phase B. However, (Mg,Fe)2Fe2O5 does not incorporate Si. Electron microprobe analyses revealed that phase B incorporates significant amounts of Fe2+ and Fe3+ (at least 1.0 cations Fe per formula unit). Fe-L2,3-edge energy-loss near-edge structure spectra confirm the presence of ferric iron [Fe3+/Fetot = 0.41(4)] and indicate substitution according to the following charge-balanced exchange: [4]Si4+ + [6]Mg2+ = 2Fe3+. The ability to accommodate Fe2+ and Fe3+ makes this potential "water-storing" mineral interesting since such substitutions should enlarge its stability field. The thermodynamic properties of Mg2Fe2O5 have been refined, yielding H°1bar,298 = - 1981.5 kJ mol- 1. Solid solution is complete across the Fe4O5-Mg2Fe2O5 binary. Molar volume decreases essentially linearly with increasing Mg content, consistent with ideal mixing behaviour. The partitioning of Mg and Fe2+ with silicates indicates that (Mg,Fe)2Fe2O5 has a strong preference for Fe2+. Modelling of partitioning with olivine is consistent with the O5-phase exhibiting ideal mixing behaviour. Mg-Fe2+ partitioning between (Mg,Fe)2Fe2O5 and ringwoodite or wadsleyite is influenced by the presence of Fe3+ and OH incorporation in the silicate phases.

Side wire feed for welding apparatus

NASA Technical Reports Server (NTRS)

Arnett, J. C.

1974-01-01

Coaxial electrode arrangement has solid central electrode, insulated outer electrode, and transverse channel for feeding wire through tip of electrode assembly. Polymeric insulation is thrust aside by pressure, which is provided by separately operated mechanism acting through central electrode.

In Situ Hydrothermally Grown TiO2@C Core-Shell Nanowire Coating for Highly Sensitive Solid Phase Microextraction of Polycyclic Aromatic Hydrocarbons.

PubMed

Wang, Fuxin; Zheng, Juan; Qiu, Junlang; Liu, Shuqin; Chen, Guosheng; Tong, Yexiang; Zhu, Fang; Ouyang, Gangfeng

2017-01-18

Nanostructured materials have great potential for solid phase microextraction (SPME) on account of their tiny size, distinct architectures and superior physical and chemical properties. Herein, a core-shell TiO 2 @C fiber for SPME was successfully fabricated by the simple hydrothermal reaction of a titanium wire and subsequent amorphous carbon coating. The readily hydrothermal procedure afforded in situ synthesis of TiO 2 nanowires on a titanium wire and provided a desirable substrate for further coating of amorphous carbon. Benefiting from the much larger surface area of subsequent TiO 2 and good adsorption property of the amorphous carbon coating, the core-shell TiO 2 @C fiber was utilized for the SPME device for the first time and proved to have better performance in extraction of polycyclic aromatic hydrocarbons. In comparison to the polydimethylsiloxane (PDMS) and PDMS/divinylbenzene (DVB) fiber for commercial use, the TiO 2 @C fiber obtained gas chromatography responses 3-8 times higher than those obtained by the commercial 100 μm PDMS and 1-9 times higher than those obtained by the 65 μm PDMS/DVB fiber. Under the optimized extraction conditions, the low detection limits were obtained in the range of 0.4-7.1 ng L -1 with wider linearity in the range of 10-2000 ng L -1 . Moreover, the fiber was successfully used for the determination of polycyclic aromatic hydrocarbons in Pearl River water, which demonstrated the applicability of the core-shell TiO 2 @C fiber.

Dual-Wavelength Interferometry and Light Emission Study for Experimental Support of Dual-Wire Ablation Experiments

NASA Astrophysics Data System (ADS)

Hamilton, Andrew; Caplinger, James; Sotnikov, Vladimir; Sarkisov, Gennady; Leland, John

2017-10-01

In the Plasma Physics and Sensors Laboratory, located at Wright Patterson Air Force Base, we utilize a pulsed power source to create plasma through a wire ablation process of metallic wires. With a parallel arrangement of wires the azimuthal magnetic fields generated around each wire, along with the Ohmic current dissipation and heating occurring upon wire evaporation, launch strong radial outflows of magnetized plasmas towards the centralized stagnation region. It is in this region that we investigate two phases of the wire ablation process. Observations in the first phase are collsionless and mostly comprised of light ions ejected from the initial corona. The second phase is observed when the wire core is ablated and heavy ions dominate collisions in the stagnation region. In this presentation we will show how dual-wavelength interferometric techniques can provide information about electron and atomic densities from experiments. Additionally, we expect white-light emission to provide a qualitative confirmation of the instabilities observed from our experiments. The material is based upon work supported by the Air Force Office of Scientific Research under Award Number 16RYCOR289.

Transurethral ultrasonic ureterolithotripsy using a solid-wire probe.

PubMed

Chaussy, C; Fuchs, G; Kahn, R; Hunter, P; Goodfriend, R

1987-05-01

A multicenter study evaluates a new technique for transurethral ultrasonic ureterolithotripsy utilizing a solid-wire probe. The transverse vibrations of the probe cause greater stone disintegration. A small ureteroscope is used and a basket is not required. There was a 96.6 per cent success rate in 118 cases. This technique has significantly improved ultrasonic lithotripsy. It has proved to be useful for upper ureteral stones not amenable to extracorporeal shock-wave lithotripsy and lower ureteral stones including "steinstrasse."

Fabrication of polyaniline-coated halloysite nanotubes by in situ chemical polymerization as a solid-phase microextraction coating for the analysis of volatile organic compounds in aqueous solutions.

PubMed

Abolghasemi, Mir Mahdi; Arsalani, Naser; Yousefi, Vahid; Arsalani, Mahmood; Piryaei, Marzieh

2016-03-01

We have synthesized an organic-inorganic polyaniline-halloysite nanotube composite by an in situ polymerization method. This nanocomposite is immobilized on a stainless-steel wire and can be used as a fiber coating for solid-phase microextraction. It was found that our new solid-phase microextraction fiber is an excellent adsorbent for the extraction of some volatile organic compounds in aqueous samples in combination with gas chromatography and mass spectrometry. The coating can be prepared easily, is mechanically stable, and exhibits relatively high thermal stability. It is capable of extracting phenolic compounds from water samples. Following thermal desorption, the phenols were quantified by gas chromatography with mass spectrometry. The effects of extraction temperature, extraction time, sample ionic strength, stirring rate, pH, desorption temperature and desorption time were studied. Under optimal conditions, the repeatability for one fiber (n = 5), expressed as the relative standard deviation, is between 6.2 and 9.1%. The detection limits range from 0.005 to 4 ng/mL. The method offers the advantage of being simple to use, with a shorter analysis time, lower cost of equipment and higher thermal stability of the fiber in comparison to conventional methods of analysis. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

46 CFR 195.35-5 - General.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 1014 (incorporated by reference, see § 195.01-3). (d) All lifelines shall be of steel or bronze wire rope. Steel wire rope shall be either inherently corrosion-resistant, or made so by galvanizing or...

46 CFR 195.35-5 - General.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 1014 (incorporated by reference, see § 195.01-3). (d) All lifelines shall be of steel or bronze wire rope. Steel wire rope shall be either inherently corrosion-resistant, or made so by galvanizing or...

Strategies for the solid-phase diversification of poly-L-proline-type II peptide mimic scaffolds and peptide scaffolds through guanidinylation.

PubMed

Flemer, Stevenson; Wurthmann, Alexander; Mamai, Ahmed; Madalengoitia, José S

2008-10-03

A strategy for the solid-phase diversification of PPII mimic scaffolds through guanidinylation is presented. The approach involves the synthesis N-Pmc-N'-alkyl thioureas as diversification reagents. Analogues of Fmoc-Orn(Mtt)-OH can be incorporated into a growing peptide chain on Wang resin. Side chain deprotection with 1% TFA/CH2Cl2 followed by EDCI-mediated reaction of N-Pmc-N'-alkyl thioureas with the side chain amine affords arginine analogues with modified guanidine head groups. The scope, limitations, and incidental chemistry are discussed.

Concurrent growth of InSe wires and In2O3 tulip-like structures in the Au-catalytic vapour-liquid-solid process

NASA Astrophysics Data System (ADS)

Taurino, A.; Signore, M. A.

2015-06-01

In this work, the concurrent growth of InSe and In2O3 nanostructures, obtained by thermal evaporation of InSe powders on Au-covered Si substrates, has been investigated by scanning and transmission electron microscopy techniques. The vapour-solid and Au catalytic vapour-liquid-solid growth mechanisms, responsible of the simultaneous development of the two different types of nanostructures, i.e. InSe wires and In2O3 tulip-like structures respectively, are discussed in detail. The thermodynamic processes giving rise to the obtained morphologies and materials are explained.

On the role of precursor powder composition in controlling microstructure, flux pinning, and the critical current density of Ag/Bi2Sr2CaCu2Ox conductors

NASA Astrophysics Data System (ADS)

Li, Pei; Naderi, Golsa; Schwartz, Justin; Shen, Tengming

2017-03-01

Precursor powder composition is known to strongly affect the critical current density (J c) of Ag/Bi2Sr2CaCu2Ox (Bi-2212) wires. However, reasons for such J c dependence have not yet been fully understood, compromising our ability to achieve further optimization. We systematically examined superconducting properties, microstructural evolution and phase transformation, and grain boundaries of Bi-2212 conductors fabricated from precursor powders with a range of compositions using a combination of transport-current measurements, a quench technique to freeze microstructures at high temperatures during heat treatment, and scanning transmission electron microscopy (STEM). Samples include both dip-coated tapes and round wires, among which a commercial round wire carries a high J c of 7600 A mm-2 at 4.2 K, self-field and 2600 A mm-2 at 4.2 K, 20 T, respectively. In the melt, this high-J c conductor, made using a composition of Bi2.17Sr1.94Ca0.89Cu2Ox, contains a uniform dispersion of fine alkaline-earth cuprate (AEC) and copper-free solid phases, whereas several low-J c conductors contain large AEC particles. Such significant differences in the phase morphologies in the melt are accompanied by a drastic difference in the formation kinetics of Bi-2212 during recrystallization cooling. STEM studies show that Bi-2212 grain colonies in the high-J c conductors have a high density of Bi2Sr2CuO y (Bi-2201) intergrowths, whereas a low-J c conductor, made using Bi2.14Sr1.66Ca1.24Cu1.96O x , is nearly free of them. STEM investigation shows grain boundaries in low-J c conductors are often insulated with a Bi-rich amorphous phase. High-J c conductors also show higher flux-pinning strength, which we ascribe to their higher Bi-2201 intergrowth density.

SOLID STATE ENERGY CONVERSION ALLIANCE DELPHI SOLID OXIDE FUEL CELL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Steven Shaffer; Sean Kelly; Subhasish Mukerjee

2003-12-08

The objective of Phase I under this project is to develop a 5 kW Solid Oxide Fuel Cell power system for a range of fuels and applications. During Phase I, the following will be accomplished: Develop and demonstrate technology transfer efforts on a 5 kW stationary distributed power generation system that incorporates steam reforming of natural gas with the option of piped-in water (Demonstration System A). Initiate development of a 5 kW system for later mass-market automotive auxiliary power unit application, which will incorporate Catalytic Partial Oxidation (CPO) reforming of gasoline, with anode exhaust gas injected into an ultra-lean burnmore » internal combustion engine. This technical progress report covers work performed by Delphi from January 1, 2003 to June 30, 2003, under Department of Energy Cooperative Agreement DE-FC-02NT41246. This report highlights technical results of the work performed under the following tasks: Task 1 System Design and Integration; Task 2 Solid Oxide Fuel Cell Stack Developments; Task 3 Reformer Developments; Task 4 Development of Balance of Plant (BOP) Components; Task 5 Manufacturing Development (Privately Funded); Task 6 System Fabrication; Task 7 System Testing; Task 8 Program Management; and Task 9 Stack Testing with Coal-Based Reformate.« less

Graphics-Printing Program For The HP Paintjet Printer

NASA Technical Reports Server (NTRS)

Atkins, Victor R.

1993-01-01

IMPRINT utility computer program developed to print graphics specified in raster files by use of Hewlett-Packard Paintjet(TM) color printer. Reads bit-mapped images from files on UNIX-based graphics workstation and prints out three different types of images: wire-frame images, solid-color images, and gray-scale images. Wire-frame images are in continuous tone or, in case of low resolution, in random gray scale. In case of color images, IMPRINT also prints by use of default palette of solid colors. Written in C language.

All optical electron injector using an intense ultrashort pulse laser and a solid wire target

NASA Astrophysics Data System (ADS)

Palchan, T.; Eisenmann, S.; Zigler, A.; Kaganovich, D.; Hubbard, R. F.; Fraenkel, M.; Fisher, D.; Henis, Z.

2006-05-01

Energetic electron bunches were generated by irradiating a solid tungsten wire 13 μm wide with 50 femtosecond pulses at an intensity of ˜3×1018 W/cm2. The electron yield, energy spectrum and angular distribution were measured. These energetic electron bunches are suitable for injection into a laser driven plasma accelerator. An all-optical electron injector based on this approach could simplify timing and alignment in future laser-plasma accelerator experiments.

Shape Memory Alloy Induced Wing Warping for a Small Unmanned Aerial Vehicle

DTIC Science & Technology

2003-06-01

strained Nitinol wires are attached to the surface of the wing. When the resistively heated wires pass a transition temperature, a phase change occurs...testing of the Nitinol wire is conducted to determine its modulus of elasticity in both its martensite and austenite phases. In addition, cycle tests are...prototype wings with Nitinol wires attached to determine the actual performance of the actuator. Using epoxy to attach the Nitinol to the wing is

Experimental constraints on reconstruction of Archean seawater Ni isotopic composition from banded iron formations

NASA Astrophysics Data System (ADS)

Wang, Shui-Jiong; Wasylenki, Laura E.

2017-06-01

The Ni isotopic systematics in banded iron formations (BIFs) potentially recorded the Ni isotopic composition of ancient seawater over Precambrian geological history. However, the utility of BIFs as proxies requires quantitative knowledge of how Ni isotopes fractionated as dissolved Ni was initially incorporated into iron-rich sediments and how diagenesis may have affected the Ni isotopic systematics. Here we report results of synthesis experiments to investigate the behavior of Ni isotopes during Ni coprecipitation with ferrihydrite and then transformation of ferrihydrite to hematite. Ferrihydrite coprecipitation experiments at neutral pH demonstrated that the dissolved Ni was variably heavier than coprecipitated Ni (likely a mixture of surface-adsorbed and structurally incorporated Ni), with the isotope fractionation becoming larger as the fraction of Ni associated with solid increased (Δ60/58Nisolution-solid = +0.08 to +0.50‰). Further experiments at lower pH (3.7-6.7), in which structurally incorporated Ni likely dominated in solids, documented a decrease in Δ60/58Nisolution-solid from +0.44‰ to -0.18‰ as the pH decreased. The negative value for Δ60/58Nisolution-solid at low pH indicates the enrichment of heavier isotopes in incorporated Ni relative to dissolved and adsorbed Ni, possibly as a result of the presence of a small amount of tetrahedral Ni2+ in addition to octahedral Ni2+ in the ferrihydrite structure. The results of the ferrihydrite experiments thus reflect equilibrium isotope fractionation between three pools of Ni, with δ60/58Ni values in the order of incorporated > dissolved > adsorbed. Hematite was synthesized by transformation of Ni-bearing ferrihydrite in aqueous solution at ∼100 °C. A significant amount of Ni (up to 60%) was released (desorbed) from solids into solutions as pH dropped from ∼7 to 4.5-5.5 upon phase transformation. Rinsing of the synthesized hematite in 2 M acetic acid released only very small amounts of Ni (<4% of total Ni, presumably surface-adsorbed) that were isotopically heavier (δ60/58Ni = +0.11 ± 0.06‰) than the residues (presumably dominated by incorporated Ni), which had δ60/58Ni of -0.26 ± 0.07‰. The preference of lighter isotopes for the incorporated Ni relative to the surface-adsorbed Ni after phase transformation (most had been released into solution) is probably due to distortion of Nisbnd O octahedra in the hematite structure, with weaker Nisbnd O bond strengths on average. Hence, the more variable Δ60/58Nisolution-solid values (-0.04 to +0.77‰) observed in hematite experiments most likely reflect thermodynamically driven Rayleigh fractionation, with incorporated Ni unavailable to exchange with dissolved Ni due to continuous reduction in size of the highly reactive surface pool of Ni, through which all solid-solution exchange must occur. Overall, the synthesized hematite was isotopically lighter than the ferrihydrite by ∼0.08‰ in δ60/58Ni, which is however within the current analytical uncertainties (±0.09‰). This implies that earliest diagenesis of BIFs results in very limited change in the isotopic composition of solid-associated Ni. Our experimental results, although conducted in a very simple system that differs from Archean seawater, represent an important step toward reconstruction of the Ni isotopic composition of ancient seawater from Ni isotopic signatures in BIFs.

Phase-field modeling of diffusional phase behaviors of solid surfaces: A case study of phase-separating Li XFePO 4 electrode particles

DOE PAGES

Heo, Tae Wook; Chen, Long-Qing; Wood, Brandon C.

2015-04-08

In this paper, we present a comprehensive phase-field model for simulating diffusion-mediated kinetic phase behaviors near the surface of a solid particle. The model incorporates elastic inhomogeneity and anisotropy, diffusion mobility anisotropy, interfacial energy anisotropy, and Cahn–Hilliard diffusion kinetics. The free energy density function is formulated based on the regular solution model taking into account the possible solute-surface interaction near the surface. The coherency strain energy is computed using the Fourier-spectral iterative-perturbation method due to the strong elastic inhomogeneity with a zero surface traction boundary condition. Employing a phase-separating Li XFePO 4 electrode particle for Li-ion batteries as a modelmore » system, we perform parametric three-dimensional computer simulations. The model permits the observation of surface phase behaviors that are different from the bulk counterpart. For instance, it reproduces the theoretically well-established surface modes of spinodal decomposition of an unstable solid solution: the surface mode of coherent spinodal decomposition and the surface-directed spinodal decomposition mode. We systematically investigate the influences of major factors on the kinetic surface phase behaviors during the diffusional process. Finally, our simulation study provides insights for tailoring the internal phase microstructure of a particle by controlling the surface phase morphology.« less

Effects of load voltage on voltage breakdown modes of electrical exploding aluminum wires in air

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Jian; Li, Xingwen, E-mail: xwli@mail.xjtu.edu.cn; Yang, Zefeng

The effects of the load voltage on the breakdown modes are investigated in exploding aluminum wires driven by a 1 kA, 0.1 kA/ns pulsed current in air. From laser probing images taken by laser shadowgraphy, schlieren imaging, and interferometry, the position of the shockwave front, the plasma channel, and the wire core edge of the exploding product can be determined. The breakdown mode makes a transition from the internal mode, which involves breakdown inside the wire core, to the shunting mode, which involves breakdown in the compressed air, with decreasing charging voltage. The breakdown electrical field for a gaseous aluminum wire coremore » of nearly solid density is estimated to be more than 20 kV/cm, while the value for gaseous aluminum of approximately 0.2% solid density decreases to 15–20 kV/cm. The breakdown field in shunting mode is less than 20 kV/cm and is strongly affected by the vaporized aluminum, the desorbed gas, and the electrons emitted from the wire core during the current pause. Ohmic heating during voltage collapses will induce further energy deposition in the current channel and thus will result in different expansion speeds for both the wire core and the shockwave front in the different modes.« less

Requirements for Printed Wiring Boards

NASA Technical Reports Server (NTRS)

1984-01-01

In order to maintain the high standards of the NASA printed wiring programs, this publication: prescribes NASA's requirements for assuring reliable rigid printed wiring boards; describes and incorporates basic considerations necessary to assure reliable rigid printed wiring boards; establishes the supplier's responsibility to train and certify personnel; provides for supplier documentation of the fabrication and inspection procedures to be used for NASA work, including supplier innovations and changes in technology; and provides visual workmanship standards to aid those responsible for determining quality conformance to the established requirements.

Molecular devices: Caroviologens as an approach to molecular wires—synthesis and incorporation into vesicle membranes

PubMed Central

Arrhenius, Thomas S.; Blanchard-Desce, Mireille; Dvolaitzky, Maya; Lehn, Jean-Marie; Malthete, Jacques

1986-01-01

Molecular wires, which would allow electron flow to take place between different components, are important elements in the design of molecular devices. An approach to such species would be molecules possessing an electron-conducting conjugated chain, terminal electroactive polar groups, and a length sufficient to span a lipid membrane. To this end, bispyridinium polyenes of different lengths have been synthesized and their incorporation into the bilayer membrane of sodium dihexadecyl phosphate vesicles has been studied. Since they combine the features of carotenoids and of viologens, they may be termed caroviologens. Vesicles containing the caroviologen whose length approximately corresponds to the thickness of the sodium dihexadecyl phosphate bilayer display temperature-dependent changes of its absorption spectrum reflecting the gel → liquid-crystal phase transition of the membrane. The data agree with a structural model in which the caroviologens of sufficient length span the bilayer membrane, the pyridinium sites being close to the negatively charged outer and inner surfaces of the sodium dihexadecyl phosphate vesicles and the polyene chain crossing the lipidic interior of the membrane. These membranes may now be tested in processes in which the caroviologen would function as a continuous, transmembrane electron channel—i.e., as a molecular wire. Various further developments may be envisaged along these lines. PMID:16593731

Structure and mechanical properties of as-received and heat-treated stainless steel orthodontic wires.

PubMed

Khier, S E; Brantley, W A; Fournelle, R A

1988-03-01

A combination of x-ray diffraction analysis with mechanical testing in tension and bending has been used to investigate the metallurgical structures and mechanical properties for as-received and heat-treated stainless steel orthodontic wires. Two different proprietary wire types were selected, having a wide range in cross-sectional dimensions: 0.016-, 0.030-, and 0.050- or 0.051-inch diameters, and 0.017 X 0.025-inch rectangular specimens. Heat treatments were performed for 10 minutes in air at temperatures of 700 degrees, 900 degrees, and 1100 degrees F. The x-ray diffraction patterns showed that the as-received 0.016-inch diameter and 0.017 X 0.025-inch wires of both proprietary types consisted of a two-phase structure containing a martensitic phase along with the austenitic phase. This duplex structure was converted entirely to austenite with heat treatment for one wire type, but persisted after heat treatment for the other wire type. The largest diameter, 0.050- or 0.051-inch, wires of both types were single-phase austenitic structure for both the as-received and heat-treated conditions. Evidence of substantial preferred crystallographic orientation or texturing in these orthodontic wires was also found by x-ray diffraction. As in our previous studies, the modulus of elasticity in bending was significantly less than the value obtained in tension for only the smaller cross-sectional wires. The 0.05 radian flexural yield strength correlated more closely with the 0.2% offset yield strength in tension than with the yield strength for 0.05% and 0.1% permanent offsets.

Solid polymer electrolyte (SPE) fuel cell technology program, phase 1/1A. [design and fabrication

NASA Technical Reports Server (NTRS)

1975-01-01

A solid polymer electrolyte fuel cell was studied for the purpose of improving the characteristics of the technology. Several facets were evaluated, namely: (1) reduced fuel cell costs; (2) reduced fuel cell weight; (3) improved fuel cell efficiency; and (4) increased systems compatibility. Demonstrated advances were incorporated into a full scale hardware design. A single cell unit was fabricated. A substantial degree of success was demonstrated.

Current collector for AMTEC

NASA Technical Reports Server (NTRS)

Williams, Roger M. (Inventor)

1989-01-01

An electrode having higher power output is formed of an open mesh current collector such as expanded nickel covering an electrode film applied to a tube of beta-alumina solid electrolyte (BASE). A plurality of cross-members such as spaced, parallel loops of molybdenum metal wire surround the BASE tube. The loops are electrically connected by a bus wire. As the AMTEC cell is heated, the grid of expanded nickel expands more than the BASE tube and the surrounding loop of wire and become diffusion welded to the electrode film and to the wire loops.

Lightning protection for shuttle propulsion elements

NASA Technical Reports Server (NTRS)

Goodloe, Carolyn C.; Giudici, Robert J.

1991-01-01

The results of lightning protection analyses and tests are weighed against the present set of waivers to the NASA lightning protection specification. The significant analyses and tests are contrasted with the release of a new and more realistic lightning protection specification, in September 1990, that resulted in an inordinate number of waivers. A variety of lightning protection analyses and tests of the Shuttle propulsion elements, the Solid Rocket Booster, the External Tank, and the Space Shuttle Main Engine, were conducted. These tests range from the sensitivity of solid propellant during shipping to penetration of cryogenic tanks during flight. The Shuttle propulsion elements have the capability to survive certain levels of lightning strikes at certain times during transportation, launch site operations, and flight. Changes are being evaluated that may improve the odds of withstanding a major lightning strike. The Solid Rocket Booster is the most likely propulsion element to survive if systems tunnel bond straps are improved. Wiring improvements were already incorporated and major protection tests were conducted. The External Tank remains vulnerable to burn-through penetration of its skin. Proposed design improvements include the use of a composite nose cone and conductive or laminated thermal protection system coatings.

Synthesis of 3'-, or 5'-, or internal methacrylamido-modified oligonucleotides

DOEpatents

Golova, Julia B.; Chernov, Boris K.

2010-04-27

New modifiers were synthesized for incorporation of a methacrylic function in 3'-, 5'- and internal positions of oligonucleotides during solid phase synthesis. A modifier was used for synthesis of 5'-methacrylated oligonucleotides for preparation of microarrays by a co-polymerization method.

Electropolymerized fluorinated aniline-based fiber for headspace solid-phase microextraction and gas chromatographic determination of benzaldehyde in injectable pharmaceutical formulations.

PubMed

Mohammadi, Ali; Mohammadi, Somayeh; Bayandori Moghaddam, Abdolmajid; Masoumi, Vahideh; Walker, Roderick B

2014-10-01

In this study, a simple method was developed and validated to detect trace levels of benzaldehyde in injectable pharmaceutical formulations by solid-phase microextraction coupled with gas chromatography-flame ionization detector. Polyaniline was electrodeposited on a platinum wire in trifluoroacetic acid solvent by cyclic voltammetry technique. This fiber shows high thermal and mechanical stability and high performance in extraction of benzaldehyde. Extraction and desorption time and temperature, salt effect and gas chromatography parameters were optimized as key parameters. At the optimum conditions, the fiber shows good linearity between peak area ratio of benzaldehyde/3-chlorobenzaldehyde and benzaldehyde concentration in the range of 50-800 ng/mL with percent relative standard deviation values ranging from 0.75 to 8.64% (n = 3). The limits of quantitation and detection were 50 and 16 ng/mL, respectively. The method has the requisite selectivity, sensitivity, accuracy and precision to assay benzaldehyde in injectable pharmaceutical dosage forms. © The Author [2013]. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Electrodeposited polyaniline as a fiber coating for solid-phase microextraction of organochlorine pesticides from water.

PubMed

Li, Xiang; Zhong, Ming; Chen, Jianmin

2008-08-01

The study on the performance of polyaniline as a fiber coating for solid-phase microextraction (SPME) purposes has been reported. Polyaniline coatings were directly electrodeposited on the surface of a stainless steel wire and applied for the extraction of some organochlorine pesticides (OCPs) from water samples. Analyses were performed using GC-electron capture detection (GC-ECD). The results obtained show that polyaniline fiber coating is suitable for the successful extraction of organochlorine compounds. This behavior is most probably due to the porous surface structure of polyaniline film, which provides large surface areas and allowed for high extraction efficiency. Experimental parameters such as adsorption and desorption conditions were studied and optimized. The optimized method has an acceptable linearity, with a concentration range of 1-5000 ng/L. Single fiber repeatability and fiber-to-fiber reproducibility were less than 12 and 17%, respectively. High environmental resistance and lower cost are among the advantages of polyaniline fibers over commercially available SPME fibers. The developed method was applied to the analysis of real water samples from Yangtse River and Tianmu Lake.

Gas chromatographic determination of polycyclic aromatic hydrocarbons in water and smoked rice samples after solid-phase microextraction using multiwalled carbon nanotube loaded hollow fiber.

PubMed

Matin, Amir Abbas; Biparva, Pourya; Gheshlaghi, Mohammad

2014-12-29

A novel solid-phase microextraction fiber was prepared based on multiwalled carbon nanotubes (MWCNTs) loaded on hollow fiber membrane pores. Stainless steel wire was used as unbreakable support. The major advantages of the proposed fiber are its (a) high reproducibility due to the uniform structure of the hollow fiber membranes, (b) high extraction capacity related to the porous structure of the hollow fiber and outstanding adsorptive characteristics of MWCNTs. The proposed fiber was applied for the microextraction of five representative polycyclic aromatic hydrocarbons (PAHs) from aqueous media (river and hubble-bubble water) and smoked rice samples followed by gas chromatographic determination. Analytical merits of the method, including high correlation coefficients [(0.9963-0.9992) and (0.9982-0.9999)] and low detection limits [(9.0-13.0ngL(-1)) and (40.0-150.0ngkg(-1))] for water and rice samples, respectively, made the proposed method suitable for the ultra-trace determination of PAHs. Copyright © 2014 Elsevier B.V. All rights reserved.

Solid-phase microextraction of phthalate esters by a new coating based on a thermally stable polypyrrole/graphene oxide composite.

PubMed

Jafari, Mostafa; Ebrahimzadeh, Homeira; Banitaba, Mohammad Hossein; Davarani, Saied Saeed Hosseiny

2014-11-01

A novel polypyrole/graphene oxide coating was made by the electrochemical polymerization of pyrrole in the presence of sodium dodecyl sulfate and graphene oxide on a platinum wire. The prepared fiber has shown a good thermal stability up to 300°C. The fiber was applied to the direct solid-phase microextraction and gas chromatographic analysis of four phthalate esters. The effect of four parameters on gas chromatography peak area including extraction temperature, extraction time, injection temperature, and ionic strength were investigated. Under the optimized conditions, the detection limits were between 0.042 and 0.26 μg/L. The intraday and interday relative standard deviations obtained at 55 μg/L, using a single fiber, were 8.2-16% and 17.3-25.6%, respectively. The method was successfully applied to the analysis of phthalate esters in two real samples of boiling water in cheap disposable clear plastic drinking cups showing recoveries from 83 to 120%. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Comparison of Ultrasound with Tensile Testing of Thermally Damaged Polyimide Insulated Wiring (MIL-W-81381)

NASA Technical Reports Server (NTRS)

Madaras, Eric I.; Anastasi, Robert F.

2002-01-01

Ultrasonic measurements were performed on MIL-W-81381/7, /12, and /21 wire, a polyimide (Kapton) insulated wire. The phase velocity for the 20-gauge MIL-W-81381/7 wire had a baseline value of 3023 plus or minus 78 m/s. After exposure to high temperatures, the wire's phase velocity rapidly increased, and reached an asymptotic value of 3598 plus or minus 20 m/s after 100 hours exposure. Similar responses were measured in other gauges. The baseline measurements of Young's moduli resulted in values of 5636 plus or minus 486, 7714 plus or minus 505, and 8767 plus or minus 292 KSI for the 20 ga, 16 ga, and 12 ga. wires respectively.

Influence of stress and phase on corrosion of a superelastic nickel-titanium orthodontic wire.

PubMed

Segal, Nadav; Hell, Jess; Berzins, David W

2009-06-01

The purpose of this investigation was to study the effect of stress and phase transformation on the corrosion properties of a superelastic nickel-titanium orthodontic wire. The phase transformation profiles of superelastic nickel-titanium (Sentalloy, GAC International, Bohemia, NY) and beta-titanium (TMA, Ormco, Orange, Calif) archwires were analyzed by using differential scanning calorimetry. The force/deflection behavior of the wires at 37 degrees C was measured in a 3-point bending test per modified American Dental Association specification no. 32. Electrochemical testing consisted of monitoring the open circuit potential (OCP) for 2 hours followed by polarization resistance and cyclic polarization tests on archwire segments engaged in a 5-bracket simulation apparatus with bend deflections of 0.75, 1.5, or 3 mm in artificial saliva at 37 degrees C. Nondeflected segments were also tested. Sentalloy was additionally examined for bending and corrosion at 5 degrees C, where it exists as martensite and is devoid of stress-induced phase transformation. OCP at 2 hours and corrosion current density (i(corr)) were analyzed by using ANOVA and Tukey tests (alpha = .05) (n = 10 per deflection). Significant differences (P < 0.05) in OCP with deflection were found for the TMA and the Sentalloy wires at 5 degrees C, but not for Sentalloy at 37 degrees C. Significant differences (P < 0.05) in i(corr) with deflection were also observed. All 3 wire groups had their lowest mean i(corr) values when not deflected. The i(corr) for superelastic Sentalloy (37 degrees C) peaked at 0.75 mm deflection before the wire's stress-induced phase transformation point and then decreased with further deflection and transformation. The i(corr) values for TMA and Sentalloy at 5 degrees C, both of which do not undergo phase transformation with deformation, continuously increased from 0 to 1.5 mm deflection before decreasing at the 3.0-mm deflection. Stress increased the corrosion rate in nickel-titanium and beta-titanium orthodontic wires. Alterations in stress/strain associated with phase transformation in superelastic nickel-titanium might alter the corrosion rate in ways different from wires not undergoing phase transformation.

Quartz/fused silica chip carriers

NASA Technical Reports Server (NTRS)

1992-01-01

The primary objective of this research and development effort was to develop monolithic microwave integrated circuit (MMIC) packaging which will operate efficiently at millimeter-wave frequencies. The packages incorporated fused silica as the substrate material which was selected due to its favorable electrical properties and potential performance improvement over more conventional materials for Ka-band operation. The first step towards meeting this objective is to develop a package that meets standard mechanical and thermal requirements using fused silica and to be compatible with semiconductor devices operating up to at least 44 GHz. The second step is to modify the package design and add multilayer and multicavity capacity to allow for application specific integrated circuits (ASIC's) to control multiple phase shifters. The final step is to adapt the package design to a phased array module with integral radiating elements. The first task was a continuation of the SBIR Phase 1 work. Phase 1 identified fused silica as a viable substrate material by demonstrating various plating, machining, and adhesion properties. In Phase 2 Task 1, a package was designed and fabricated to validate these findings. Task 2 was to take the next step in packaging and fabricate a multilayer, multichip module (MCM). This package is the predecessor to the phased array module and demonstrates the ability to via fill, circuit print, laminate, and to form vertical interconnects. The final task was to build a phased array module. The radiating elements were to be incorporated into the package instead of connecting to it with wire or ribbon bonds.

SRB Altitude Switch Assembly Wire Harness Failure

NASA Technical Reports Server (NTRS)

Blanche, Jim

2002-01-01

This paper presents an assessment of two wire harness failures that had occurred in Solid Rocket Booster Altitude Switch Assemblies S/N 200001 and S/N 20002. A list of modifications to EDU #4 and modification of qualification units 2000001 and 2000002 are also presented.

Solid-Phase Synthesis of Difficult Purine-Rich PNAs through Selective Hmb Incorporation: Application to the Total Synthesis of Cell Penetrating Peptide-PNAs

PubMed Central

Tailhades, Julien; Takizawa, Hotake; Gait, Michael J.; Wellings, Don A.; Wade, John D.; Aoki, Yoshitsugu; Shabanpoor, Fazel

2017-01-01

Antisense oligonucleotide (ASO)-based drug development is gaining significant momentum following the recent FDA approval of Eteplirsen (an ASO based on phosphorodiamidate morpholino) and Spinraza (2′-O-methoxyethyl-phosphorothioate) in late 2016. Their attractiveness is mainly due to the backbone modifications which have improved the in vivo characteristics of oligonucleotide drugs. Another class of ASO, based on peptide nucleic acid (PNA) chemistry, is also gaining popularity as a platform for development of gene-specific therapy for various disorders. However, the chemical synthesis of long PNAs, which are more target-specific, remains an ongoing challenge. Most of the reported methodology for the solid-phase synthesis of PNA suffer from poor coupling efficiency which limits production to short PNA sequences of less than 15 residues. Here, we have studied the effect of backbone modifications with Hmb (2-hydroxy-4-methoxybenzyl) and Dmb (2,4-dimethoxybenzyl) to ameliorate difficult couplings and reduce “on-resin” aggregation. We firstly synthesized a library of PNA dimers incorporating either Hmb or Dmb and identified that Hmb is superior to Dmb in terms of its ease of removal. Subsequently, we used Hmb backbone modification to synthesize a 22-mer purine-rich PNA, targeting dystrophin RNA splicing, which could not be synthesized by standard coupling methodology. Hmb backbone modification allowed this difficult PNA to be synthesized as well as to be continued to include a cell-penetrating peptide on the same solid support. This approach provides a novel and straightforward strategy for facile solid-phase synthesis of difficult purine-rich PNA sequences. PMID:29094037

Solid-Phase Synthesis of Difficult Purine-Rich PNAs through Selective Hmb Incorporation: Application to the Total Synthesis of Cell Penetrating Peptide-PNAs.

PubMed

Tailhades, Julien; Takizawa, Hotake; Gait, Michael J; Wellings, Don A; Wade, John D; Aoki, Yoshitsugu; Shabanpoor, Fazel

2017-01-01

Antisense oligonucleotide (ASO)-based drug development is gaining significant momentum following the recent FDA approval of Eteplirsen (an ASO based on phosphorodiamidate morpholino) and Spinraza (2'- O -methoxyethyl-phosphorothioate) in late 2016. Their attractiveness is mainly due to the backbone modifications which have improved the in vivo characteristics of oligonucleotide drugs. Another class of ASO, based on peptide nucleic acid (PNA) chemistry, is also gaining popularity as a platform for development of gene-specific therapy for various disorders. However, the chemical synthesis of long PNAs, which are more target-specific, remains an ongoing challenge. Most of the reported methodology for the solid-phase synthesis of PNA suffer from poor coupling efficiency which limits production to short PNA sequences of less than 15 residues. Here, we have studied the effect of backbone modifications with Hmb (2-hydroxy-4-methoxybenzyl) and Dmb (2,4-dimethoxybenzyl) to ameliorate difficult couplings and reduce "on-resin" aggregation. We firstly synthesized a library of PNA dimers incorporating either Hmb or Dmb and identified that Hmb is superior to Dmb in terms of its ease of removal. Subsequently, we used Hmb backbone modification to synthesize a 22-mer purine-rich PNA, targeting dystrophin RNA splicing, which could not be synthesized by standard coupling methodology. Hmb backbone modification allowed this difficult PNA to be synthesized as well as to be continued to include a cell-penetrating peptide on the same solid support. This approach provides a novel and straightforward strategy for facile solid-phase synthesis of difficult purine-rich PNA sequences.

Solid-phase synthesis of difficult purine-rich PNAs through selective Hmb incorporation: Application to the total synthesis of cell penetrating peptide-PNAs

NASA Astrophysics Data System (ADS)

Tailhades, Julien; Takizawa, Hotake; Gait, Michael J.; Wellings, Don A.; Wade, John D.; Aoki, Yoshitsugu; Shabanpoor, Fazel

2017-10-01

Antisense oligonucleotide (ASO)-based drug development is gaining significant momentum following the recent FDA approval of Eteplirsen (an ASO based on phosphorodiamidate morpholino) and Spinraza (2’-O-methoxyethyl-phosphorothioate) in late 2016. Their attractiveness is mainly due to the backbone modifications which have improved the in vivo characteristics of oligonucleotide drugs. Another class of ASO, based on peptide nucleic acid (PNA) chemistry, is also gaining popularity as a platform for development of gene-specific therapy for various disorders. However, the chemical synthesis of long PNAs, which are more target-specific, remains an ongoing challenge. Most of the reported methodology for the solid-phase synthesis of PNA suffer from poor coupling efficiency which limits production to short PNA sequences of less than 15 residues. Here we have studied the effect of backbone modifications with Hmb (2-hydroxy-4-methoxybenzyl) and Dmb (2,4-dimethoxybenzyl) to ameliorate difficult couplings and reduce “on-resin” aggregation. We firstly synthesized a library of PNA dimers incorporating either Hmb or Dmb and identified that Hmb is superior to Dmb in terms of its ease of removal. Subsequently, we used Hmb backbone modification to synthesize a 22-mer purine-rich PNA, targeting dystrophin RNA splicing, which could not be synthesized by standard coupling methodology. Hmb backbone modification allowed this difficult PNA to be synthesized as well as to be continued to include a cell-penetrating peptide on the same solid support. This approach provides a novel and straightforward strategy for facile solid-phase synthesis of difficult purine-rich PNA sequences.

Electrodes for solid state gas sensor

DOEpatents

Mukundan, Rangachary [Santa Fe, NM; Brosha, Eric L [Los Alamos, NM; Garzon, Fernando [Santa Fe, NM

2007-05-08

A mixed potential electrochemical sensor for the detection of gases has a ceria-based electrolyte with a surface for exposing to the gases to be detected, and with a reference wire electrode and a sensing wire electrode extending through the surface and fixed within the electrolyte as the electrolyte is compressed and sintered. The electrochemical sensor is formed by placing a wire reference electrode and a wire sensing electrode in a die, where each electrode has a first compressed planar section and a second section depending from the first section with the second section of each electrode extending axially within the die. The die is filled with an oxide-electrolyte powder and the powder is pressed within the die with the wire electrodes. The wire-electrodes and the pressed oxide-electrolyte powder are sintered to form a ceramic electrolyte base with a reference wire electrode and a sensing wire electrode depending therefrom.

Electrodes for solid state gas sensor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mukundan, Rangachary; Brosha, Eric L; Garzon, Fernando

2007-05-08

A mixed potential electrochemical sensor for the detection of gases has a ceria-based electrolyte with a surface for exposing to the gases to be detected, and with a reference wire electrode and a sensing wire electrode extending through the surface and fixed within the electrolyte as the electrolyte is compressed and sintered. The electrochemical sensor is formed by placing a wire reference electrode and a wire sensing electrode in a die, where each electrode has a first compressed planar section and a second section depending from the first section with the second section of each electrode extending axially within themore » die. The die is filled with an oxide-electrolyte powder and the powder is pressed within the die with the wire electrodes. The wire-electrodes and the pressed oxide-electrolyte powder are sintered to form a ceramic electrolyte base with a reference wire electrode and a sensing wire electrode depending therefrom.« less

Electrodes for solid state gas sensor

DOEpatents

Mukundan, Rangachary; Brosha, Eric L.; Garzon, Fernando

2003-08-12

A mixed potential electrochemical sensor for the detection of gases has a ceria-based electrolyte with a surface for exposing to the gases to be detected, and with a reference wire electrode and a sensing wire electrode extending through the surface and fixed within the electrolyte as the electrolyte is compressed and sintered. The electrochemical sensor is formed by placing a wire reference electrode and a wire sensing electrode in a die, where each electrode has a first compressed planar section and a second section depending from the first section with the second section of each electrode extending axially within the die. The die is filled with an oxide-electrolyte powder and the powder is pressed within the die with the wire electrodes. The wire-electrodes and the pressed oxide-electrolyte powder are sintered to form a ceramic electrolyte base with a reference wire electrode and a sensing wire electrode depending therefrom.

Electrodeposition of self-assembled poly(3,4-ethylenedioxythiophene) @gold nanoparticles on stainless steel wires for the headspace solid-phase microextraction and gas chromatographic determination of several polycyclic aromatic hydrocarbons.

PubMed

Yang, Liu; Zhang, Jie; Zhao, Faqiong; Zeng, Baizhao

2016-11-04

In this work, a novel poly(3,4-ethylenedioxythiophene)@Au nanoparticles (PEDOT@AuNPs) hybrid coating was prepared and characterized. Firstly, the monomer 3,4-ethylenedioxythiophene was self-assembled on AuNPs, and then electropolymerization was performed on a stainless steel wire by cyclic voltammetry. The obtained PEDOT@AuNPs coating was rough and showed cauliflower-like micro-structure with thickness of ∼40μm. It displayed high thermal stability (up to 330°C) and mechanical stability and could be used for at least 160 times of solid phase microextraction (SPME) without decrease of extraction performance. The coating exhibited high extraction capacity for some environmental pollutants (e.g. naphthalene, 2-methylnaphthalene, acenaphthene, fluorene and phenathrene) due to the hydrophobic interaction between the analytes and PEDOT and the additional physicochemical affinity between polycyclic aromatic hydrocarbons and AuNPs. Through coupling with GC detection, good linearity (correlation coefficients higher than 0.9894), wide linear range (0.01-100μgL -1 ), low limits of detection (2.5-25ngL -1 ) were achieved for these analytes. The reproducibility (defined as RSD) was 1.1-4.0% and 5.8-9.9% for single fiber (n=5) and fiber-to-fiber (n=5), respectively. The SPME-GC method was successfully applied for the determination of three real samples, and the recoveries for standards added were 89.9-106% for lake water, 95.7-112% for rain water and 93.2-109% for soil saturated water, respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

Cyclic Fatigue Resistance of Novel Rotary Files Manufactured from Different Thermal Treated Nickel-Titanium Wires in Artificial Canals.

PubMed

Karataşlıoglu, E; Aydın, U; Yıldırım, C

2018-02-01

The aim of this in vitro study was to compare the static cyclic fatigue resistance of thermal treated rotary files with a conventional nickel-titanium (NiTi) rotary file. Four groups of 60 rotary files with similar file dimensions, geometries, and motion were selected. Groups were set as HyFlex Group [controlled memory wire (CM-Wire)], ProfileVortex Group (M-Wire), Twisted File Group (R-Phase Wire), and OneShape Group (conventional NiTi wire)] and tested using a custom-made static cyclic fatigue testing apparatus. The fracture time and fragment length of the each file was also recorded. Statistical analysis was performed using one-way analysis of variance and Tukey's test at the 95% confidence level (P = 0.05). The HyFlex group had a significantly higher mean cyclic fatigue resistance than the other three groups (P < 0.001). The OneShape groups had the least fatigue resistance. CM-Wire alloy represented the best performance in cyclic fatigue resistance, and NiTi alloy in R-Phase had the second highest fatigue resistance. CM and R-Phase manufacturing technology processed to the conventional NiTi alloy enhance the cyclic fatigue resistance of files that have similar design and size. M-wire alloy did not show any superiority in cyclic fatigue resistance when compared with conventional NiTi wire.

Coprecipitation of Arsenate and Arsenite with Green Rust Minerals

EPA Science Inventory

The objectives of this experiment were to evaluate the extent and nature of arsenic co-precipitation with green rusts and to examine the influence of arsenic incorporation on the mineralogy of formed solid phases. Stoichiometric green rusts were obtained by coprecipitation of fe...

Solid freeform fabrication apparatus and methods

NASA Technical Reports Server (NTRS)

Taminger, Karen M. (Inventor); Watson, J. Kevin (Inventor); Hafley, Robert A. (Inventor); Petersen, Daniel D. (Inventor)

2007-01-01

An apparatus for formation of a three dimensional object comprising a sealed container; an electron beam subsystem capable of directing energy within said container; a positioning subsystem contained within said container; a wire feed subsystem contained within said container; an instrumentation subsystem electronically connected to said electron beam subsystem, positioning subsystem, and wire feed subsystem; and a power distribution subsystem electrically connected to said electron beam subsystem, positioning subsystem, wire feed subsystem, and said instrumentation subsystem.

Fine-Scale Mechanical Properties of Sliding Solids.

DTIC Science & Technology

1987-02-28

experiments to be described, the tip was prepared by chemical polishing or electropolishing and welded to a loop of wire that could be resistively heated in...attach the sample to a wire mesh that could be resistively heated itself to high temperatures. Where neither of these methods were appropriate...section welded to the tip wire . The reflected beam is focussed onto an optical detector (also outside the chamber) which is sensitive to small changes

Preparation and application of carbon nanotubes/poly(o-toluidine) composite fibers for the headspace solid-phase microextraction of benzene, toluene, ethylbenzene, and xylenes.

PubMed

Behzadi, Mansoureh; Noroozian, Ebrahim; Mirzaei, Mohammad

2013-11-01

A novel nanocomposite coating of poly(o-toluidine) and oxidized multiwalled CNTs (MWCNTs, where CNTs is carbon nanotubes) was electrochemically prepared on a stainless-steel wire. The applicability of the fiber was assessed for the headspace solid-phase microextraction of benzene, toluene, ethylbenzene, and xylenes in aqueous samples followed by GC with flame ionization detection. In order to obtain an adherent and stable composite coating, several experimental parameters related to the coating process, such as polymerization potential and time, and the concentration of o-toluidine and oxidized MWCNTs were optimized. The combination of MWCNTs and polymer in a nanocomposite form presents desirable opportunities to produce materials for new applications. The effects of various parameters on the efficiency of the headspace solid-phase microextraction process, such as desorption temperature and time, extraction temperature and time, and ionic strength were also investigated. At the optimum conditions, LODs were 0.03-0.06 μg/L. The method showed linearity in the range of 0.5-300 μg/L with coefficients of determination >0.99. The intraday and interday RSDs obtained at a 5 μg/L concentration level (n = 5) using a single fiber were 1.2-5.2 and 3.2-7.5%, respectively. The fiber-to-fiber RSD (%; n = 3) at 5 μg/L was 6.1-9.2%. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Polarization-sensitive nanowire photodetectors based on solution-synthesized CdSe quantum-wire solids.

PubMed

Singh, Amol; Li, Xiangyang; Protasenko, Vladimir; Galantai, Gabor; Kuno, Masaru; Xing, Huili Grace; Jena, Debdeep

2007-10-01

Polarization-sensitive photodetectors are demonstrated using solution-synthesized CdSe nanowire (NW) solids. Photocurrent action spectra taken with a tunable white light source match the solution linear absorption spectra of the NWs, showing that the NW network is responsible for the device photoconductivity. Temperature-dependent transport measurements reveal that carriers responsible for the dark current through the nanowire solids are thermally excited across CdSe band gap. The NWs are aligned using dielectrophoresis between prepatterned electrodes using conventional optical photolithography. The photocurrent through the NW solid is found to be polarization-sensitive, consistent with complementary absorption (emission) measurements of both single wires and their ensembles. The range of solution-processed semiconducting NW materials, their facile synthesis, ease of device fabrication, and compatibility with a variety of substrates make them attractive for potential nanoscale polarization-sensitive photodetectors.

Nonlinear Optics Technology. Volume 1. Solid State Laser Technology. Phase 3

DTIC Science & Technology

1991-01-12

84 Figure 5.6 Modulator diffraction efficiency as a function of peak power for several 86 RF frequencies Figure 5.7 Thermal effects in the modulator. a...far-field profile of a beam making a 87 double pass through the modulator operating with a peak power of 80 W and average power of 1.6 W. b) same...AU three shown incorporate phase conjugation to provide good beam quality. Figure 1.1a is a standard phase conjugated master oscillator power

'All-solid-state' electrochemistry of a protein-confined polymer electrolyte film

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parthasarathy, Meera; Pillai, Vijayamohanan K.; Mulla, Imtiaz S.

2007-12-07

Interfacial redox behavior of a heme protein (hemoglobin) confined in a solid polymer electrolyte membrane, Nafion (a perfluoro sulfonic acid ionomer) is investigated using a unique 'all-solid-state' electrochemical methodology. The supple phase-separated structure of the polymer electrolyte membrane, with hydrophilic pools containing solvated protons and water molecules, is found to preserve the incorporated protein in its active form even in the solid-state, using UV-visible, Fluorescence (of Tryptophan and Tyrosine residues) and DRIFT (diffuse reflectance infrared Fourier transform) spectroscopy. More specifically, solid-state cyclic voltammetry and electrochemical impedance of the protein-incorporated polymer films reveal that the Fe{sup 2+}-form of the entrapped proteinmore » is found to bind molecular oxygen more strongly than the native protein. In the 'all-solid-state' methodology, as there is no need to dip the protein-modified electrode in a liquid electrolyte (like the conventional electrochemical methods), it offers an easier means to study a number of proteins in a variety of polymer matrices (even biomimetic assemblies). In addition, the results of the present investigation could find interesting application in a variety of research disciplines, in addition to its fundamental scientific interest, including protein biotechnology, pharmaceutical and biomimetic chemistry.« less

Progress toward a tungsten alloy wire/high temperature alloy composite turbine blade

NASA Technical Reports Server (NTRS)

Ritzert, F. J.; Dreshfield, R. L.

1992-01-01

A tungsten alloy wire reinforced high temperature alloy composite is being developed for potential application as a hollow turbine blade for advanced rocket engine turbopumps. The W-24Re-HfC alloy wire used for these composite blades provides an excellent balance of strength and wire ductility. Preliminary fabrication, specimen design, and characterization studies were conducted by using commercially available W218 tungsten wire in place of the W-24Re-Hfc wire. Subsequently, two-ply, 50 vol pct composite panels using the W-24Re-HfC wire were fabricated. Tensile tests and metallographic studies were performed to determine the material viability. Tensile strengths of a Waspaloy matrix composite at 870 C were 90 pct of the value expected from rule-of-mixtures calculations. During processing of this Waspaloy matrix composite, a brittle phase was formed at the wire/matrix interface. Circumferential wire cracks were found in this phase. Wire coating and process evaluation efforts were performed in an attempt to solve the reaction problem. Although problems were encountered in this study, wire reinforced high temperature alloy composites continue to show promise for turbopump turbine blade material improvement.

Manufacturing and quality control of interconnecting wire harnesses, Volume 2

NASA Technical Reports Server (NTRS)

1972-01-01

Interconnecting wire harnesses defined in the design standard are considered, including type 4, open bundle (not enclosed). Knowledge gained through experience on the Saturn 5 program coupled with recent advances in techniques, materials, and processes was incorporated into the document.

Measurement of frequency response in short thermocouple wires

NASA Technical Reports Server (NTRS)

Forney, L. J.; Meeks, E. L.; Ma, J.; Fralick, G. C.

1993-01-01

Experimental measurements are made for the steady-state frequency response of a supported thermocouple wire. In particular, the effects of axial heat conduction are demonstrated for both a supported one material wire (type K) and a two material wire (type T) with unequal material properties across the junction. The data for the amplitude ratio and phase angle are correlated to within 10 percent with the theoretical predictions of Fralick and Forney (1991). This is accomplished by choosing a natural frequency omega(sub n) for the wire data to correlate the first order response at large gas temperature frequencies. It is found that a large bead size, however, will increase the amplitude ratio at low frequencies but decrease the natural frequency of the wire. The phase angle data are also distorted for imperfect junctions.

Measurement of frequency response in short thermocouple wires

NASA Technical Reports Server (NTRS)

Forney, L. J.; Meeks, E. L.; Ma, J.

1991-01-01

Experimental measurements are made for the steady-state frequency response of a supported thermocouple wire. In particular, the effects of axial heat conduction are demonstrated for both a supported one material wire (type K) and a two material wire (type T) with unequal material properties across the junction. The data for the amplitude ratio and phase angle are correlated to within 10 percent with the theoretical predictions of Fralick and Forney (1991). This is accomplished by choosing a natural frequency omega(sub n) for the wire data to correlate the first order response at large gas temperature frequencies. It is found that a large bead size, however, will increase the amplitude ratio at low frequencies but decreas the natural frequency of the wire. The phase angle data are also distorted for imperfect junctions.

Carbothermal shock synthesis of high-entropy-alloy nanoparticles

NASA Astrophysics Data System (ADS)

Yao, Yonggang; Huang, Zhennan; Xie, Pengfei; Lacey, Steven D.; Jacob, Rohit Jiji; Xie, Hua; Chen, Fengjuan; Nie, Anmin; Pu, Tiancheng; Rehwoldt, Miles; Yu, Daiwei; Zachariah, Michael R.; Wang, Chao; Shahbazian-Yassar, Reza; Li, Ju; Hu, Liangbing

2018-03-01

The controllable incorporation of multiple immiscible elements into a single nanoparticle merits untold scientific and technological potential, yet remains a challenge using conventional synthetic techniques. We present a general route for alloying up to eight dissimilar elements into single-phase solid-solution nanoparticles, referred to as high-entropy-alloy nanoparticles (HEA-NPs), by thermally shocking precursor metal salt mixtures loaded onto carbon supports [temperature ~2000 kelvin (K), 55-millisecond duration, rate of ~105 K per second]. We synthesized a wide range of multicomponent nanoparticles with a desired chemistry (composition), size, and phase (solid solution, phase-separated) by controlling the carbothermal shock (CTS) parameters (substrate, temperature, shock duration, and heating/cooling rate). To prove utility, we synthesized quinary HEA-NPs as ammonia oxidation catalysts with ~100% conversion and >99% nitrogen oxide selectivity over prolonged operations.

Duality symmetry and power-law fading of frustration in a quantum multiconnected superconductor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, S.N.; Ralston, J.P.

1991-03-01

We generalize the Alexander--de Gennes equations to a new system of superconducting-wire networks, allowing for variation of the cross-sectional area of wires. The generalized equations are solved for a square lattice of different cross-sectional-area ratios {lambda} in the {ital x} and {ital y} directions. A symmetry of {lambda}{r arrow}1/{lambda} is related to the Aubry-Andre duality and an obvious geometric property. We find that even a slight geometric asymmetry can soften the fine structure of the magnetic phase boundary considerably. We obtain a power-law dependence on the parameter {lambda} as {lambda}{r arrow}{infinity} and {lambda}{r arrow}0. For a finite-area ratio {lambda}, wemore » speculate that a simple analytic fit incorporating the dual symmetry is close to the exact nonperturbative behavior. The system is also related analytically to a recent study of Hu and Chen, which revealed a power-law behavior for a rectangular lattice.« less

Fischer-Tropsch Slurry Reactor modeling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soong, Y.; Gamwo, I.K.; Harke, F.W.

1995-12-31

This paper reports experimental and theoretical results on hydrodynamic studies. The experiments were conducted in a hot-pressurized Slurry-Bubble Column Reactor (SBCR). It includes experimental results of Drakeol-10 oil/nitrogen/glass beads hydrodynamic study and the development of an ultrasonic technique for measuring solids concentration. A model to describe the flow behavior in reactors was developed. The hydrodynamic properties in a 10.16 cm diameter bubble column with a perforated-plate gas distributor were studied at pressures ranging from 0.1 to 1.36 MPa, and at temperatures from 20 to 200{degrees}C, using a dual hot-wire probe with nitrogen, glass beads, and Drakeol-10 oil as the gas,more » solid, and liquid phase, respectively. It was found that the addition of 20 oil wt% glass beads in the system has a slight effect on the average gas holdup and bubble size. A well-posed three-dimensional model for bed dynamics was developed from an ill-posed model. The new model has computed solid holdup distributions consistent with experimental observations with no artificial {open_quotes}fountain{close_quotes} as predicted by the earlier model. The model can be applied to a variety of multiphase flows of practical interest. An ultrasonic technique is being developed to measure solids concentration in a three-phase slurry reactor. Preliminary measurements have been made on slurries consisting of molten paraffin wax, glass beads, and nitrogen bubbles at 180 {degrees}C and 0.1 MPa. The data show that both the sound speed and attenuation are well-defined functions of both the solid and gas concentrations in the slurries. The results suggest possibilities to directly measure solids concentration during the operation of an autoclave reactor containing molten wax.« less

Gas-phase detection of solid-state fission product complexes for post-detonation nuclear forensic analysis

DOE PAGES

Stratz, S. Adam; Jones, Steven A.; Oldham, Colton J.; ...

2016-06-27

This study presents the first known detection of fission products commonly found in post-detonation nuclear debris samples using solid sample introduction and a uniquely coupled gas chromatography inductively-coupled plasma time-of-flight mass spectrometer. Rare earth oxides were chemically altered to incorporate a ligand that enhances the volatility of the samples. These samples were injected (as solids) into the aforementioned instrument and detected for the first time. Repeatable results indicate the validity of the methodology, and this capability, when refined, will prove to be a valuable asset for rapid post-detonation nuclear forensic analysis.

Gas-phase detection of solid-state fission product complexes for post-detonation nuclear forensic analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stratz, S. Adam; Jones, Steven A.; Oldham, Colton J.

This study presents the first known detection of fission products commonly found in post-detonation nuclear debris samples using solid sample introduction and a uniquely coupled gas chromatography inductively-coupled plasma time-of-flight mass spectrometer. Rare earth oxides were chemically altered to incorporate a ligand that enhances the volatility of the samples. These samples were injected (as solids) into the aforementioned instrument and detected for the first time. Repeatable results indicate the validity of the methodology, and this capability, when refined, will prove to be a valuable asset for rapid post-detonation nuclear forensic analysis.

Structural and phase transformations in zinc and brass wires under heating with high-density current pulse

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pervikov, A. V.

The work is focused on revealing the mechanism of structure and phase transformations in the metal wires under heating with a high-density current pulse (the electric explosion of wires, EEWs). It has been demonstrated on the example of brass and zinc wires that the transition of a current pulse with the density of j ≈ 3.3 × 10{sup 7} A/cm{sup 2} results in homogeneous heating of the crystalline structure of the metal/alloy. It has been determined that under heating with a pulse of high-density current pulse, the electric resistance of the liquid phases of zinc and brass decreases as the temperature increases. The results obtainedmore » allow for a conclusion that the presence of the particles of the condensed phase in the expanding products of EEW is the result of overheating instabilities in the liquid metal.« less

High Power Diode Laser-Treated HP-HVOF and Twin Wire Arc-Sprayed Coatings for Fossil Fuel Power Plants

NASA Astrophysics Data System (ADS)

Mann, B. S.

2013-08-01

This article deals with high power diode laser (HPDL) surface modification of twin wire arc-sprayed (TWAS) and high pressure high velocity oxy-fuel (HP-HVOF) coatings to combat solid particle erosion occurring in fossil fuel power plants. To overcome solid particle impact wear above 673 K, Cr3C2-NiCr-, Cr3C2-CoNiCrAlY-, and WC-CrC-Ni-based HVOF coatings are used. WC-CoCr-based HVOF coatings are generally used below 673 K. Twin wire arc (TWA) spraying of Tafa 140 MXC and SHS 7170 cored wires is used for a wide range of applications for a temperature up to 1073 K. Laser surface modification of high chromium stainless steels for steam valve components and LPST blades is carried out regularly. TWA spraying using SHS 7170 cored wire, HP-HVOF coating using WC-CoCr powder, Ti6Al4V alloy, and high chromium stainless steels (X20Cr13, AISI 410, X10CrNiMoV1222, 13Cr4Ni, 17Cr4Ni) were selected in the present study. Using robotically controlled parameters, HPDL surface treatments of TWAS-coated high strength X10CrNiMoV1222 stainless steel and HP-HVOF-coated AISI 410 stainless steel samples were carried out and these were compared with HPDL-treated high chromium stainless steels and titanium alloy for high energy particle impact wear (HEPIW) resistance. The HPDL surface treatment of the coatings has improved the HEPIW resistance manifold. The improvement in HPDL-treated stainless steels and titanium alloys is marginal and it is not comparable with that of HPDL-treated coatings. These coatings were also compared with "as-sprayed" coatings for fracture toughness, microhardness, microstructure, and phase analyses. The HEPIW resistance has a strong relationship with the product of fracture toughness and microhardness of the HPDL-treated HP-HVOF and TWAS SHS 7170 coatings. This development opens up a possibility of using HPDL surface treatments in specialized areas where the problem of HEPIW is very severe. The HEPIW resistance of HPDL-treated high chromium stainless steels and titanium alloys, HPDL-treated TWAS SHS 7170 and HP-HVOF coatings, and their micrographs and X-ray diffraction analysis is reported in this article.

Solid-phase extraction microfluidic devices for matrix removal in trace element assay of actinide materials

DOE PAGES

Gao, Jun; Manard, Benjamin Thomas; Castro, Alonso; ...

2017-02-02

Advances in sample nebulization and injection technology have significantly reduced the volume of solution required for trace impurity analysis in plutonium and uranium materials. Correspondingly, we have designed and tested a novel chip-based microfluidic platform, containing a 100-µL or 20-µL solid-phase microextraction column, packed by centrifugation, which supports nuclear material mass and solution volume reductions of 90% or more compared to standard methods. Quantitative recovery of 28 trace elements in uranium was demonstrated using a UTEVA chromatographic resin column, and trace element recovery from thorium (a surrogate for plutonium) was similarly demonstrated using anion exchange resin AG MP-1. Of ninemore » materials tested, compatibility of polyvinyl chloride (PVC), polypropylene (PP), and polytetrafluoroethylene (PTFE) chips with the strong nitric acid media was highest. Finally, the microcolumns can be incorporated into a variety of devices and systems, and can be loaded with other solid-phase resins for trace element assay in high-purity metals.« less

Solid-phase extraction microfluidic devices for matrix removal in trace element assay of actinide materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, Jun; Manard, Benjamin Thomas; Castro, Alonso

Advances in sample nebulization and injection technology have significantly reduced the volume of solution required for trace impurity analysis in plutonium and uranium materials. Correspondingly, we have designed and tested a novel chip-based microfluidic platform, containing a 100-µL or 20-µL solid-phase microextraction column, packed by centrifugation, which supports nuclear material mass and solution volume reductions of 90% or more compared to standard methods. Quantitative recovery of 28 trace elements in uranium was demonstrated using a UTEVA chromatographic resin column, and trace element recovery from thorium (a surrogate for plutonium) was similarly demonstrated using anion exchange resin AG MP-1. Of ninemore » materials tested, compatibility of polyvinyl chloride (PVC), polypropylene (PP), and polytetrafluoroethylene (PTFE) chips with the strong nitric acid media was highest. Finally, the microcolumns can be incorporated into a variety of devices and systems, and can be loaded with other solid-phase resins for trace element assay in high-purity metals.« less

A statistical approach to the brittle fracture of a multi-phase solid

NASA Technical Reports Server (NTRS)

Liu, W. K.; Lua, Y. I.; Belytschko, T.

1991-01-01

A stochastic damage model is proposed to quantify the inherent statistical distribution of the fracture toughness of a brittle, multi-phase solid. The model, based on the macrocrack-microcrack interaction, incorporates uncertainties in locations and orientations of microcracks. Due to the high concentration of microcracks near the macro-tip, a higher order analysis based on traction boundary integral equations is formulated first for an arbitrary array of cracks. The effects of uncertainties in locations and orientations of microcracks at a macro-tip are analyzed quantitatively by using the boundary integral equations method in conjunction with the computer simulation of the random microcrack array. The short range interactions resulting from surrounding microcracks closet to the main crack tip are investigated. The effects of microcrack density parameter are also explored in the present study. The validity of the present model is demonstrated by comparing its statistical output with the Neville distribution function, which gives correct fits to sets of experimental data from multi-phase solids.

Three-Man Solid Electrolyte Carbon Dioxide Electrolysis Breadboard

NASA Technical Reports Server (NTRS)

Isenberg, Arnold O.

1989-01-01

The development of the Three-Man (2.2 lb CO2/man-day) Solid Electrolyte CO2 Electrolysis Breadboard consisted of a Phase 1 and 2 effort. The Phase 1 effort constituted fabrication of three electrolysis cell types and performing parametric testing, off-design testing, and cell life testing. The Phase 2 consisted of the preliminary design, incorporation of palladium (Pd) tubes for hydrogen separation from the electrolyzer cathode feed gases, design support testing, final design, fabrication, and performance testing of the breadboard system. The results of performance tests demonstrated that CO2 electrolysis in an oxygen reclamation system for long duration space-based habitats is feasible. Closure of the oxygen system loop, therefore, can be achieved by CO2 electrolysis. In a two step process the metabolic CO2 and H2O vapor are electrolyzed into O2, H2, and CO. The CO can subsequently be disproportionated into carbon and CO2 in a carbon deposition reactor and the CO2 in turn be recycled and electrolyzed for total O2 recovery. The development effort demonstrated electrolyzer system can be designed and built to operate safely and reliably and the incorporation of Pd tubes for hydrogen diffusion can be integrated safely with predictable performance.

Gastric emptying and intragastric distribution of lipids in man. A new scintigraphic method of study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jian, R.; Vigneron, N.; Najean, Y.

1982-08-01

We measured gastric emptying of fat and water from a solid-liquid meal in healthy volunteers using a tubeless scintigraphic method. /sup 75/Se glycerol triether, incorporated in butter, was the lipid-phase marker, and /sup 99m/Tcm, ingested with 250 ml water, the non-lipid phase marker. In seven of these subjects we also measured the gastric emptying of solids and liquids with /sup 99m/Tc bound to cooked egg whites as the solid-phase marker and /sup 111/In ingested with 250 ml water as the marker of the solid and aqueous phases. Emptying and intragastric repartition of each marker were measured by detection of radioactivitymore » changes over the abdominal area using a gamma-camera. The stability and the specificity of the labeling was checked for each marker. Mean gastric emptying rate (expressed as percentage ingested marker emptied per hr) of lipids (17.4 +/- 2.4) was much lower than that of the rest of the meal (34.2 +/- 1.8) and slightly, but significantly, lower than that of solids (22.8 +/- 1.8). An intragastric layering of fat above nonlipids was observed only after the first postprandial hour and remained moderate. Thus, lipids are emptied more slowly than any other component of an ordinary meal, and this is not due only to layering of fat above water.« less

High pressure study of water-salt systems, phase equilibria, partitioning, thermodynic properties and implication for large icy worlds hydrospheres.

NASA Astrophysics Data System (ADS)

Journaux, B.; Brown, J. M.; Abramson, E.; Petitgirard, S.; Pakhomova, A.; Boffa Ballaran, T.; Collings, I.

2017-12-01

Water salt systems are predicted to be present in deep hydrosphere inside water-rich planetary bodies, following water/rock chemical interaction during early differentiation stages or later hydrothermal activity. Unfortunately the current knowledge of the thermodynamic and physical properties of aqueous salt mixtures at high pressure and high temperature is still insufficient to allow realistic modeling of the chemical or dynamic of thick planetary hydrospheres. Recent experimental results have shown that the presence of solutes, and more particularly salts, in equilibrium with high pressure ices have large effects on the stability fields, buoyancy and chemistry of all the phases present at these extreme conditions. Effects currently being investigated by our research group also covers ice melting curve depressions that depend on the salt species and incorporation of solutes inside the crystallographic lattice of high pressure ices. Both of these could have very important implication at the planetary scale, enabling thicker/deeper liquid oceans, and allowing chemical transportation through the high pressure ice layer in large icy worlds. We will present the latest results obtained in-situ using diamond anvil cell, coupled with Synchrotron X-Ray diffraction, Raman Spectroscopy and optical observations, allowing to probe the crystallographic structure, equations of state, partitioning and phase boundary of high pressure ice VI and VII in equilibrium with Na-Mg-SO4-Cl ionic species at high pressures (1-10 GPa). The difference in melting behavior depending on the dissolved salt species was characterized, suggesting differences in ionic speciation at liquidus conditions. The solidus P-T conditions were also measured as well as an increase of lattice volumes interpreted as an outcome of ionic incorporation in HP ice during incongruent crystallization. The measured phase diagrams, lattice volumes and important salt incorporations suggest a more complex picture of the structure, dynamic and evolution of icy worlds hydrospheres that could allow, among others, deep liquid reservoirs, chemical transport at the solid state through HP ices layers and/or complex dynamic due to salt exsolutions at HP ices solid-solid phase boundaries.

Boron-Based Hydrogen Storage: Ternary Borides and Beyond

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vajo, John J.

DOE continues to seek reversible solid-state hydrogen materials with hydrogen densities of ≥11 wt% and ≥80 g/L that can deliver hydrogen and be recharged at moderate temperatures (≤100 °C) and pressures (≤100 bar) enabling incorporation into hydrogen storage systems suitable for transportation applications. Boron-based hydrogen storage materials have the potential to meet the density requirements given boron’s low atomic weight, high chemical valance, and versatile chemistry. However, the rates of hydrogen exchange in boron-based compounds are thus far much too slow for practical applications. Although contributing to the high hydrogen densities, the high valance of boron also leads to slowmore » rates of hydrogen exchange due to extensive boron-boron atom rearrangements during hydrogen cycling. This rearrangement often leads to multiple solid phases occurring over hydrogen release and recharge cycles. These phases must nucleate and react with each other across solid-solid phase boundaries leading to energy barriers that slow the rates of hydrogen exchange. This project sought to overcome the slow rates of hydrogen exchange in boron-based hydrogen storage materials by minimizing the number of solid phases and the boron atom rearrangement over a hydrogen release and recharge cycle. Two novel approaches were explored: 1) developing matched pairs of ternary borides and mixed-metal borohydrides that could exchange hydrogen with only one hydrogenated phase (the mixed-metal borohydride) and only one dehydrogenated phase (the ternary boride); and 2) developing boranes that could release hydrogen by being lithiated using lithium hydride with no boron-boron atom rearrangement.« less

Selected developments in laser wire stripping. [cutting insulation from aerospace-type wires and cables

NASA Technical Reports Server (NTRS)

1977-01-01

The operation of mechanical and thermal strippers and the early development of laser wire strippers are reviewed. NASA sponsored development of laser wire stripping for space shuttle includes bench-type strippers as well as an advanced portable hand-held stripper which incorporates a miniaturized carbon dioxide laser and a rotating optics unit with a gas-jet assist and debris exhaust. Drives and controls girdle the wire and slit the remaining slug without manual assistance. This unit can strip wire sizes 26 through 12 gage. A larger-capacity hand-held unit for wire sizes through 1/0 gage was built using a neodynium-doped yttrium aluminum garnet (Nd:YAG) laser. The hand-held units have a flexible umbilical cable to an accompanying cart that carries the power supply, gas supply, cooling unit, and the controls.

Simple circuit monitors "third wire" in ac lines

NASA Technical Reports Server (NTRS)

Kojima, T. T.; Stuck, D. E.

1980-01-01

Device detects interruption of ground connection in three-wire electrical equipment and shuts off ac power to prevent shock hazard. Silicon-controlled rectifiers detect floating ground, and deenergize optoelectric relays thereby breaking power connections. Circuit could be incorporated into hand tools, appliances, and other electrical equipment.

In-drop capillary spooling of spider capture thread inspires hybrid fibers with mixed solid-liquid mechanical properties.

PubMed

Elettro, Hervé; Neukirch, Sébastien; Vollrath, Fritz; Antkowiak, Arnaud

2016-05-31

An essential element in the web-trap architecture, the capture silk spun by ecribellate orb spiders consists of glue droplets sitting astride a silk filament. Mechanically this thread presents a mixed solid-liquid behavior unknown to date. Under extension, capture silk behaves as a particularly stretchy solid, owing to its molecular nanosprings, but it totally switches behavior in compression to now become liquid-like: It shrinks with no apparent limit while exerting a constant tension. Here, we unravel the physics underpinning the unique behavior of this "liquid wire" and demonstrate that its mechanical response originates in the shape-switching of the silk filament induced by buckling within the droplets. Learning from this natural example of geometry and mechanics, we manufactured programmable liquid wires that present previously unidentified pathways for the design of new hybrid solid-liquid materials.

Beam Position and Phase Monitor - Wire Mapping System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watkins, Heath A; Shurter, Robert B.; Gilpatrick, John D.

2012-04-10

The Los Alamos Neutron Science Center (LANSCE) deploys many cylindrical beam position and phase monitors (BPPM) throughout the linac to measure the beam central position, phase and bunched-beam current. Each monitor is calibrated and qualified prior to installation to insure it meets LANSCE requirements. The BPPM wire mapping system is used to map the BPPM electrode offset, sensitivity and higher order coefficients. This system uses a three-axis motion table to position the wire antenna structure within the cavity, simulating the beam excitation of a BPPM at a fundamental frequency of 201.25 MHz. RF signal strength is measured and recorded formore » the four electrodes as the antenna position is updated. An effort is underway to extend the systems service to the LANSCE facility by replacing obsolete electronic hardware and taking advantage of software enhancements. This paper describes the upgraded wire positioning system's new hardware and software capabilities including its revised antenna structure, motion control interface, RF measurement equipment and Labview software upgrades. The main purpose of the wire mapping system at LANSCE is to characterize the amplitude response versus beam central position of BPPMs before they are installed in the beam line. The wire mapping system is able to simulate a beam using a thin wire and measure the signal response as the wire position is varied within the BPPM aperture.« less

NiCo2S4 nanosheet-decorated 3D, porous Ni film@Ni wire electrode materials for all solid-state asymmetric supercapacitor applications.

PubMed

Saravanakumar, Balasubramaniam; Jayaseelan, Santhana Sivabalan; Seo, Min-Kang; Kim, Hak-Yong; Kim, Byoung-Suhk

2017-12-07

Wire type supercapacitors with high energy and power densities have generated considerable interest in wearable applications. Herein, we report a novel NiCo 2 S 4 -decorated 3D, porous Ni film@Ni wire electrode for high performance supercapacitor application. In this work, a facile method is introduced to fabricate a 3D, porous Ni film deposited on a Ni wire as a flexible electrode, followed by decoration with NiCo 2 S 4 as an electroactive material. The fabricated NiCo 2 S 4 -decorated 3D, porous Ni film@Ni wire electrode displays a superior performance with an areal and volumetric capacitance of 1.228 F cm -2 and 199.74 F cm -3 , respectively, at a current density of 0.2 mA cm -1 with a maximum volumetric energy and power density (E V : 6.935 mW h cm -3 ; P V : 1.019 W cm -3 ). Finally, the solid state asymmetric wire type supercapacitor is fabricated using the fabricated NiCo 2 S 4 -decorated 3D, porous Ni film@Ni wire as a positive electrode and N-doped reduced graphene oxide (N-rGO) as a negative electrode and this exhibits good areal and volumetric capacitances of C A : 0.12 F cm -2 and C V : 19.57 F cm -2 with a higher rate capability (92%). This asymmetric wire type supercapacitor demonstrates a low leakage current and self-discharge with a maximum volumetric energy (E V : 5.33 mW h cm -3 ) and power (P V : 855.69 mW cm -3 ) density.

A comparative evaluation of the tensile strength of silver soldered joints of stainless steel and cobalt chromium orthodontic wires with band material--an in vitro study.

PubMed

Dua, R; Nandlal, B

2004-03-01

The present study was conducted to compare and evaluate the tensile strength of silver soldered joints of stainless steel and cobalt-chromium orthodontic wires with band material. An attempt was made to observe the effect of joint site preparation by incorporation of tack welding and increasing metal to metal surface contact area by flattening an end of the wire prior to soldering along with the regularly used round wires without tack welding. A total of 180 wire specimens were soldered to 180 band specimens. Fifteen samples according to joint site preparation were included for each of the wire groups i.e. Gloria (S.S.), Remanium (S.S.) and Remaloy (Co-Cr) wires of 0.036" in diameter. The findings of the study were suggestive that all three wires may be used for preparing silver soldered joints irrespective of the quality of the wire. However, when subjecting the wire to joint site preparation, Gloria (S.S.) wire showed less tensile strength as compared to Remanium and Remaloy.

Metal organic vapour-phase epitaxy growth of GaN wires on Si (111) for light-emitting diode applications

PubMed Central

2013-01-01

GaN wires are grown on a Si (111) substrate by metal organic vapour-phase epitaxy on a thin deposited AlN blanket and through a thin SiNx layer formed spontaneously at the AlN/Si interface. N-doped wires are used as templates for the growth of core-shell InGaN/GaN multiple quantum wells coated by a p-doped shell. Standing single-wire heterostructures are connected using a metallic tip and a Si substrate backside contact, and the electroluminescence at room temperature and forward bias is demonstrated at 420 nm. This result points out the feasibility of lower cost nitride-based wires for light-emitting diode applications. PMID:23391377

Phase transformation and deformation behavior of NiTi-Nb eutectic joined NiTi wires

PubMed Central

Wang, Liqiang; Wang, Cong; Zhang, Lai-Chang; Chen, Liangyu; Lu, Weijie; Zhang, Di

2016-01-01

NiTi wires were brazed together via eutectic reaction between NiTi and Nb powder deposited at the wire contact region. Phase transformation and deformation behavior of the NiTi-Nb eutectic microstructure were investigated using transmission electron microscopy (TEM) and cyclic loading-unloading tests. Results show that R phase and B19′ martensite transformation are induced by plastic deformation. R phase transformation, which significantly contributes to superelasticity, preferentially occurs at the interfaces between NiTi and eutectic region. Round-shaped Nb-rich phase with rod-like and lamellar-type eutectics are observed in eutectic regions. These phases appear to affect the deformation behavior of the brazed NiTi-Nb region via five distinct stages in stress-strain curves: (I) R phase reorientation, (II) R phase transformation from parent phase, (III) elastic deformation of reoriented martensite accompanied by the plastic deformation of Nb-rich phase and lamellar NiTi-Nb eutectic, (IV) B19′ martensitic transformation, and (V) plastic deformation of the specimen. PMID:27049025

Volume reduction of hot cell plastic wastes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dykes, F W; Henscheid, J P; Lewis, L C

1989-09-19

The disposal of radioactively-contaminated solid wastes has become a national crisis. In such circumstances, it is imperative that this waste be reduced to minimum volume and be packaged to prevent pollution of the environment. The majority of the solid waste generated at the hot cell under consideration is plastic lab ware. Cutting this waste into small pieces with a hot wire technique reduced the volume 66%. Melting the waste, although more time consuming, reduced the volume 90%. The hot wire technique can also be used to cut up damaged master slave manipulator boots, greatly reducing their disposal volume.

Optimization of microwire/glass-fibre reinforced polymer composites for wind turbine application

NASA Astrophysics Data System (ADS)

Qin, F. X.; Peng, H. X.; Chen, Z.; Wang, H.; Zhang, J. W.; Hilton, G.

2013-11-01

We here report a comprehensive study of glass-fibre reinforced polymers (GFRP) incorporating ferromagnetic microwires for microwave absorption applications. With wire addition, a remarkable dependence of microwave absorption performance appears on the local properties of wires such as wire geometry and the mesostructure such as inter-wire spacing, as well as the embedded depth of the wires layer. The impact testing further demonstrates that the metallic microwires can to some extent improve the impact performance. Based on both the absorption and impact behavior, we propose an optimized design of the microwire/GFRP composites to achieve simultaneous best possible absorption and impact performance for multifunctional applications in aeronautical structures and wind turbines.

Apparatus and Method for Increasing the Diameter of Metal Alloy Wires Within a Molten Metal Pool

DOEpatents

Hartman, Alan D.; Argetsinger, Edward R.; Hansen, Jeffrey S.; Paige, Jack I.; King, Paul E.; Turner, Paul C.

2002-01-29

In a dip forming process the core material to be coated is introduced directly into a source block of coating material eliminating the need for a bushing entrance component. The process containment vessel or crucible is heated so that only a portion of the coating material becomes molten, leaving a solid portion of material as the entrance port of, and seal around, the core material. The crucible can contain molten and solid metals and is especially useful when coating core material with reactive metals. The source block of coating material has been machined to include a close tolerance hole of a size and shape to closely fit the core material. The core material moves first through the solid portion of the source block of coating material where the close tolerance hole has been machined, then through a solid/molten interface, and finally through the molten phase where the diameter of the core material is increased. The crucible may or may not require water-cooling depending upon the type of material used in crucible construction. The system may operate under vacuum, partial vacuum, atmospheric pressure, or positive pressure depending upon the type of source material being used.

Apparatus and method for increasing the diameter of metal alloy wires within a molten metal pool

DOEpatents

Hartman, Alan D.; Argetsinger, Edward R.; Hansen, Jeffrey S.; Paige, Jack I.; King, Paul E.; Turner, Paul C.

2002-01-29

In a dip forming process the core material to be coated is introduced directly into a source block of coating material eliminating the need for a bushing entrance component. The process containment vessel or crucible is heated so that only a portion of the coating material becomes molten, leaving a solid portion of material as the entrance port of, and seal around, the core material. The crucible can contain molten and solid metals and is especially useful when coating core material with reactive metals. The source block of coating material has been machined to include a close tolerance hole of a size and shape to closely fit the core material. The core material moves first through the solid portion of the source block of coating material where the close tolerance hole has been machined, then through a solid/molten interface, and finally through the molten phase where the diameter of the core material is increased. The crucible may or may not require water-cooling depending upon the type of material used in crucible construction. The system may operate under vacuum, partial vacuum, atmospheric pressure, or positive pressure depending upon the type of source material being used.

Laboratory investigations of Titan haze formation: In situ measurement of gas and particle composition

NASA Astrophysics Data System (ADS)

Hörst, Sarah M.; Yoon, Y. Heidi; Ugelow, Melissa S.; Parker, Alex H.; Li, Rui; de Gouw, Joost A.; Tolbert, Margaret A.

2018-02-01

Prior to the arrival of the Cassini-Huygens spacecraft, aerosol production in Titan's atmosphere was believed to begin in the stratosphere where chemical processes are predominantly initiated by far ultraviolet (FUV) radiation. However, measurements taken by the Cassini Ultraviolet Imaging Spectrograph (UVIS) and Cassini Plasma Spectrometer (CAPS) indicate that haze formation initiates in the thermosphere where there is a greater flux of extreme ultraviolet (EUV) photons and energetic particles available to initiate chemical reactions, including the destruction of N2. The discovery of previously unpredicted nitrogen species in measurements of Titan's atmosphere by the Cassini Ion and Neutral Mass Spectrometer (INMS) indicates that nitrogen participates in the chemistry to a much greater extent than was appreciated before Cassini. The degree of nitrogen incorporation in the haze particles is important for understanding the diversity of molecules that may be present in Titan's atmosphere and on its surface. We have conducted a series of Titan atmosphere simulation experiments using either spark discharge (Tesla coil) or FUV photons (deuterium lamp) to initiate chemistry in CH4/N2 gas mixtures ranging from 0.01% CH4/99.99% N2 to 10% CH4/90% N2. We obtained in situ real-time measurements using a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) to measure the particle composition as a function of particle size and a proton-transfer ion-trap mass spectrometer (PIT-MS) to measure the composition of gas phase products. These two techniques allow us to investigate the effect of energy source and initial CH4 concentration on the degree of nitrogen incorporation in both the gas and solid phase products. The results presented here confirm that FUV photons produce not only solid phase nitrogen bearing products but also gas phase nitrogen species. We find that in both the gas and solid phase, nitrogen is found in nitriles rather than amines and that both the gas phase and solid phase products are composed primarily of molecules with a low degree of aromaticity. The UV experiments reproduce the absolute abundances measured in Titan's stratosphere for a number of gas phase species including C4H2, C6H6, HCN, CH3CN, HC3N, and C2H5CN.

Manufacture and quality control of interconnecting wire harnesses, Volume 3

NASA Technical Reports Server (NTRS)

1972-01-01

The document covers interconnecting wire harnesses defined in the design standard, including type 6, enclosed in TFE heat shrink tubing; and type 7, flexible armored. Knowledge gained through experience on the Saturn 5 program coupled with recent advances in techniques, materials, and processes was incorporated into this document.

46 CFR 195.35-5 - General.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 1014 (incorporated by reference, see § 195.01-3). (d) All lifelines shall be of steel or bronze wire rope. Steel wire rope shall be either inherently corrosion-resistant, or made so by galvanizing or... breaking strength of 1,500 pounds. (e) All equipment shall be maintained in an operative condition, and it...

46 CFR 195.35-5 - General.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 1014 (incorporated by reference, see § 195.01-3). (d) All lifelines shall be of steel or bronze wire rope. Steel wire rope shall be either inherently corrosion-resistant, or made so by galvanizing or... breaking strength of 1,500 pounds. (e) All equipment shall be maintained in an operative condition, and it...

46 CFR 195.35-5 - General.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 1014 (incorporated by reference, see § 195.01-3). (d) All lifelines shall be of steel or bronze wire rope. Steel wire rope shall be either inherently corrosion-resistant, or made so by galvanizing or... breaking strength of 1,500 pounds. (e) All equipment shall be maintained in an operative condition, and it...

SOLID STATE ENERGY CONVERSION ALLIANCE DELPHI SOFC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Steven Shaffer; Sean Kelly; Subhasish Mukerjee

2003-06-09

The objective of Phase I under this project is to develop a 5 kW Solid Oxide Fuel Cell power system for a range of fuels and applications. During Phase I, the following will be accomplished: Develop and demonstrate technology transfer efforts on a 5 kW stationary distributed power generation system that incorporates steam reforming of natural gas with piped-in water (Demonstration System A); and Initiate development of a 5 kW system for later mass-market automotive auxiliary power unit application, which will incorporate Catalytic Partial Oxidation (CPO) reforming of gasoline, with anode exhaust gas injected into an ultra-lean burn internal combustionmore » engine. This technical progress report covers work performed by Delphi from July through December 2002 under Department of Energy Cooperative Agreement DE-FC-02NT41246 for the 5 kW mass-market automotive (gasoline) auxiliary power unit. This report highlights technical results of the work performed under the following tasks for the automotive 5 kW system: Task 1--System Design and Integration; Task 2--Solid Oxide Fuel Cell Stack Developments; Task 3--Reformer Developments; Task 4--Development of Balance of Plant (BOP) Components; Task 5--Manufacturing Development (Privately Funded); Task 6--System Fabrication; and Task 7--System Testing.« less

Transformation toughened ceramics for the heavy duty diesel engine technology program

NASA Technical Reports Server (NTRS)

Musikant, S.; Feingold, E.; Rauch, H.; Samanta, S.

1984-01-01

The objective of this program is to develop an advanced high temperature oxide structural ceramic for application to the heavy duty diesel engine. The approach is to employ transformation toughening by additions of ZrO.5HfO.5O2 solid solution to the oxide ceramics, mullite (2Al2O3S2SiO2) and alumina (Al2O3). The study is planned for three phases, each 12 months in duration. This report covers Phase 1. During this period, processing techniques were developed to incorporate the ZrO.5HfO.5O2 solid solution in the matrices while retaining the necessary metastable tetragonal phase. Modulus of rupture and of elasticity, coefficient of thermal expansion, fracture toughness by indent technique and thermal diffusivity of representative specimens were measured. In Phase 2, the process will be improved to provide higher mechanical strength and to define the techniques for scale up to component size. In Phase 3, full scale component prototypes will be fabri-]cated.

Multiphase mean curvature flows with high mobility contrasts: A phase-field approach, with applications to nanowires

NASA Astrophysics Data System (ADS)

Bretin, Elie; Danescu, Alexandre; Penuelas, José; Masnou, Simon

2018-07-01

The structure of many multiphase systems is governed by an energy that penalizes the area of interfaces between phases weighted by surface tension coefficients. However, interface evolution laws depend also on interface mobility coefficients. Having in mind some applications where highly contrasted or even degenerate mobilities are involved, for which classical phase field models are inapplicable, we propose a new effective phase field approach to approximate multiphase mean curvature flows with mobilities. The key aspect of our model is to incorporate the mobilities not in the phase field energy (which is conventionally the case) but in the metric which determines the gradient flow. We show the consistency of such an approach by a formal analysis of the sharp interface limit. We also propose an efficient numerical scheme which allows us to illustrate the advantages of the model on various examples, as the wetting of droplets on solid surfaces or the simulation of nanowires growth generated by the so-called vapor-liquid-solid method.

On the role of precursor powder composition in controlling microstructure, flux pinning, and the critical current density of Ag/Bi$$_2$$Sr$$_2$$CaCu$$_2$$O$$_x$$ conductors

DOE PAGES

Li, Pei; Naderi, Golsa; Schwartz, Justin; ...

2017-01-04

Precursor powder composition is known to strongly affect the critical current density (J c) of Ag/Bimore » $$_2$$Sr$$_2$$CaCu$$_2$$O$$_x$$ (Bi-2212) wires. However, reasons for such J c dependence have not yet been fully understood, compromising our ability to achieve further optimization. In this paper, we systematically examined superconducting properties, microstructural evolution and phase transformation, and grain boundaries of Bi-2212 conductors fabricated from precursor powders with a range of compositions using a combination of transport-current measurements, a quench technique to freeze microstructures at high temperatures during heat treatment, and scanning transmission electron microscopy (STEM). Samples include both dip-coated tapes and round wires, among which a commercial round wire carries a high J c of 7600 A mm -2 at 4.2 K, self-field and 2600 A mm -2 at 4.2 K, 20 T, respectively. In the melt, this high-J c conductor, made using a composition of Bi 2.17Sr 1.94Ca 0.89Cu 2O x, contains a uniform dispersion of fine alkaline-earth cuprate (AEC) and copper-free solid phases, whereas several low-J c conductors contain large AEC particles. Such significant differences in the phase morphologies in the melt are accompanied by a drastic difference in the formation kinetics of Bi-2212 during recrystallization cooling. STEM studies show that Bi-2212 grain colonies in the high-J c conductors have a high density of Bi 2Sr 2CuO y (Bi-2201) intergrowths, whereas a low-J c conductor, made using Bi 2.14Sr 1.66Ca 1.24Cu 1.96O x , is nearly free of them. STEM investigation shows grain boundaries in low-J c conductors are often insulated with a Bi-rich amorphous phase. Finally, high-J c conductors also show higher flux-pinning strength, which we ascribe to their higher Bi-2201 intergrowth density.« less

On the role of precursor powder composition in controlling microstructure, flux pinning, and the critical current density of Ag/Bi$$_2$$Sr$$_2$$CaCu$$_2$$O$$_x$$ conductors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Pei; Naderi, Golsa; Schwartz, Justin

Precursor powder composition is known to strongly affect the critical current density (J c) of Ag/Bimore » $$_2$$Sr$$_2$$CaCu$$_2$$O$$_x$$ (Bi-2212) wires. However, reasons for such J c dependence have not yet been fully understood, compromising our ability to achieve further optimization. In this paper, we systematically examined superconducting properties, microstructural evolution and phase transformation, and grain boundaries of Bi-2212 conductors fabricated from precursor powders with a range of compositions using a combination of transport-current measurements, a quench technique to freeze microstructures at high temperatures during heat treatment, and scanning transmission electron microscopy (STEM). Samples include both dip-coated tapes and round wires, among which a commercial round wire carries a high J c of 7600 A mm -2 at 4.2 K, self-field and 2600 A mm -2 at 4.2 K, 20 T, respectively. In the melt, this high-J c conductor, made using a composition of Bi 2.17Sr 1.94Ca 0.89Cu 2O x, contains a uniform dispersion of fine alkaline-earth cuprate (AEC) and copper-free solid phases, whereas several low-J c conductors contain large AEC particles. Such significant differences in the phase morphologies in the melt are accompanied by a drastic difference in the formation kinetics of Bi-2212 during recrystallization cooling. STEM studies show that Bi-2212 grain colonies in the high-J c conductors have a high density of Bi 2Sr 2CuO y (Bi-2201) intergrowths, whereas a low-J c conductor, made using Bi 2.14Sr 1.66Ca 1.24Cu 1.96O x , is nearly free of them. STEM investigation shows grain boundaries in low-J c conductors are often insulated with a Bi-rich amorphous phase. Finally, high-J c conductors also show higher flux-pinning strength, which we ascribe to their higher Bi-2201 intergrowth density.« less

Modeling, simulation and optimization of a no-chamber solid oxide fuel cell operated with a flat-flame burner

NASA Astrophysics Data System (ADS)

Vogler, Marcel; Horiuchi, Michio; Bessler, Wolfgang G.

A detailed computational model of a direct-flame solid oxide fuel cell (DFFC) is presented. The DFFC is based on a fuel-rich methane-air flame stabilized on a flat-flame burner and coupled to a solid oxide fuel cell (SOFC). The model consists of an elementary kinetic description of the premixed methane-air flame, a stagnation-point flow description of the coupled heat and mass transport within the gas phase, an elementary kinetic description of the electrochemistry, as well as heat, mass and charge transport within the SOFC. Simulated current-voltage characteristics show excellent agreement with experimental data published earlier (Kronemayer et al., 2007 [10]). The model-based analysis of loss processes reveals that ohmic resistance in the current collection wires dominates polarization losses, while electronic loss currents in the mixed conducting electrolyte have only little influence on the polarized cell. The model was used to propose an optimized cell design. Based on this analysis, power densities of above 200 mW cm -2 can be expected.

Transfer impedance measurements of the space shuttle Solid Rocket Motor (SRM) joints, wire meshes and a carbon graphite motor case

NASA Technical Reports Server (NTRS)

Papazian, Peter B.; Perala, Rodney A.; Curry, John D.; Lankford, Alan B.; Keller, J. David

1988-01-01

Using three different current injection methods and a simple voltage probe, transfer impedances for Solid Rocket Motor (SRM) joints, wire meshes, aluminum foil, Thorstrand and a graphite composite motor case were measured. In all cases, the surface current distribution for the particular current injection device was calculated analytically or by finite difference methods. The results of these calculations were used to generate a geometric factor which was the ratio of total injected current to surface current density. The results were validated in several ways. For wire mesh measurements, results showed good agreement with calculated results for a 14 by 18 Al screen. SRM joint impedances were independently verified. The filiment wound case measurement results were validated only to the extent that their curve shape agrees with the expected form of transfer impedance for a homogeneous slab excited by a plane wave source.

Nonenzymatic all-solid-state coated wire electrode for acetylcholine determination in vitro.

PubMed

He, Cheng; Wang, Zhan; Wang, You; Hu, Ruifen; Li, Guang

2016-11-15

A nonenzymatic all-solid-state coated wire acetylcholine electrode was investigated. Poly(3,4-ethylenedioxythiophene) doped with poly(styrenesulfonate) (PEDOT/PSS) as conducting polymer was coated on one end of a gold wire (0.5mm in diameter). The acetylcholine selective membrane containing heptakis(2,3,6-tri-Ο-methyl)-β-cyclodextrin as an ionophore covered the conducting polymer layer. The electrode could work stably in a pH range of 6.5-8.5 and a temperature range of 15-40°C. It covered an acetylcholine concentration range of 10(-5)-10(-1)M with a slope of 54.04±1.70mV/decade, while detection limit was 5.69±1.06µM. The selectivity, dynamic response, reproducibility and stability were evaluated. The electrode could work properly in the rat brain homogenate to detect different concentrations of acetylcholine. Copyright © 2016 Elsevier B.V. All rights reserved.

Phase-field model of vapor-liquid-solid nanowire growth

NASA Astrophysics Data System (ADS)

Wang, Nan; Upmanyu, Moneesh; Karma, Alain

2018-03-01

We present a multiphase-field model to describe quantitatively nanowire growth by the vapor-liquid-solid (VLS) process. The free-energy functional of this model depends on three nonconserved order parameters that distinguish the vapor, liquid, and solid phases and describe the energetic properties of various interfaces, including arbitrary forms of anisotropic γ plots for the solid-vapor and solid-liquid interfaces. The evolution equations for those order parameters describe basic kinetic processes including the rapid (quasi-instantaneous) equilibration of the liquid catalyst to a droplet shape with constant mean curvature, the slow incorporation of growth atoms at the droplet surface, and crystallization within the droplet. The standard constraint that the sum of the phase fields equals unity and the conservation of the number of catalyst atoms, which relates the catalyst volume to the concentration of growth atoms inside the droplet, are handled via separate Lagrange multipliers. An analysis of the model is presented that rigorously maps the phase-field equations to a desired set of sharp-interface equations for the evolution of the phase boundaries under the constraint of force balance at three-phase junctions (triple points) given by the Young-Herring relation that includes torque term related to the anisotropy of the solid-liquid and solid-vapor interface excess free energies. Numerical examples of growth in two dimensions are presented for the simplest case of vanishing crystalline anisotropy and the more realistic case of a solid-liquid γ plot with cusped minima corresponding to two sets of (10 ) and (11 ) facets. The simulations reproduce many of the salient features of nanowire growth observed experimentally, including growth normal to the substrate with tapering of the side walls, transitions between different growth orientations, and crawling growth along the substrate. They also reproduce different observed relationships between the nanowire growth velocity and radius depending on the growth condition. For the basic normal growth mode, the steady-state solid-liquid interface tip shape consists of a main facet intersected by two truncated side facets ending at triple points. The ratio of truncated and main facet lengths are in quantitative agreement with the prediction of sharp-interface theory that is developed here for faceted nanowire growth in two dimensions.

Enhanced zero-bias Majorana peak in the differential tunneling conductance of disordered multisubband quantum-wire/superconductor junctions.

PubMed

Pientka, Falko; Kells, Graham; Romito, Alessandro; Brouwer, Piet W; von Oppen, Felix

2012-11-30

A recent experiment Mourik et al. [Science 336, 1003 (2012)] on InSb quantum wires provides possible evidence for the realization of a topological superconducting phase and the formation of Majorana bound states. Motivated by this experiment, we consider the signature of Majorana bound states in the differential tunneling conductance of multisubband wires. We show that the weight of the Majorana-induced zero-bias peak is strongly enhanced by mixing of subbands, when disorder is added to the end of the quantum wire. We also consider how the topological phase transition is reflected in the gap structure of the current-voltage characteristic.

Synthesis and structural studies on cerium substituted La0.4Ca0.6MnO3 as solid oxide fuel cell electrode material

NASA Astrophysics Data System (ADS)

Singh, Monika; Kumar, Dinesh; Singh, Akhilesh Kumar

2018-04-01

For solid oxide fuel cell electrode material, calcium doped lanthanum manganite La0.4Ca0.6MnO3 (LCMO) and cerium-incorporated on Ca-site with composition La0.40Ca0.55Ce0.05MnO3 (LCCMO) were synthesized using most feasible and efficient glycine-nitrate method. The formation of crystalline single phase was confirmed by x-ray diffraction (XRD). The Rietveld analysis reveals that both systems crystallize into orthorhombic crystal structure with Pnma space group. Additionally, 8 mole % Y2O3 stabilized ZrO2 (8YSZ) solid electrolyte was also synthesized using high energy ball mill to check the reaction with electrode materials. It was found that the substitution of Ce+4 cations in LCMO perovskite suppressed formation of undesired insulating CaZrO3 phase.

Temperature-modulated DSC provides new insight about nickel-titanium wire transformations.

PubMed

Brantley, William A; Iijima, Masahiro; Grentzer, Thomas H

2003-10-01

Differential scanning calorimetry (DSC) is a well-known method for investigating phase transformations in nickel-titanium orthodontic wires; the microstructural phases and phase transformations in these wires have central importance for their clinical performance. The purpose of this study was to use the more recently developed technique of temperature-modulated DSC (TMDSC) to gain insight into transformations in 3 nickel-titanium orthodontic wires: Neo Sentalloy (GAC International, Islandia, NY), 35 degrees C Copper Ni-Ti (Ormco, Glendora, Calif) and Nitinol SE (3M Unitek, Monrovia, Calif). In the oral environment, the first 2 superelastic wires have shape memory, and the third wire has superelastic behavior but not shape memory. All wires had cross-section dimensions of 0.016 x 0.022 in. Archwires in the as-received condition and after bending 135 degrees were cut into 5 or 6 segments for test specimens. TMDSC analyses (Model 2910 DSC, TA Instruments, Wilmington, Del) were conducted between -125 degrees C and 100 degrees C, using a linear heating and cooling rate of 2 degrees C per min, an oscillation amplitude of 0.318 degrees C with a period of 60 seconds, and helium as the purge gas. For all 3 wire alloys, strong low-temperature martensitic transformations, resolved on the nonreversing heat-flow curves, were not present on the reversing heat-flow curves, and bending appeared to increase the enthalpy change for these peaks in some cases. For Neo Sentalloy, TMDSC showed that transformation between martensitic and austenitic nickel-titanium, suggested as occurring directly in the forward and reverse directions by conventional DSC, was instead a 2-step process involving the R-phase. Two-step transformations in the forward and reverse directions were also found for 35 degrees C Copper Ni-Ti and Nitinol SE. The TMDSC results show that structural transformations in these wires are complex. Some possible clinical implications of these observations are discussed.

New insight on Li and B isotope fractionation during serpentinization derived from batch reaction investigations

NASA Astrophysics Data System (ADS)

Hansen, Christian T.; Meixner, Anette; Kasemann, Simone A.; Bach, Wolfgang

2017-11-01

Multiple batch experiments (100 °C, 200 °C; 40 MPa) were conducted, using Dickson-type reactors, to investigate Li and B partitioning and isotope fractionation between rock and water during serpentinization. We reacted fresh olivine (5 g; Fo90; [B] = <0.02 μg/g; δ11BOlivine -14‰; [Li] = 1.7 μg/g; δ7LiOlivine = +5.3‰) with seawater-like fluids (75 ml, 3.2 wt.% NaCl) adjusted with respect to their Li (0.2, 0.5 μg/ml; and δ7LiFluid +55‰) and B (∼10 μg/ml and δ11BFluid -0.3‰) characteristics. At 200 °C a reaction turnover of about 70% and a serpentinization mineral assemblage matching equilibrium thermodynamic computational results (EQ3/6) developed after 224 days runtime. Characterization of concomitant fluid samples indicated a distinct B incorporation into solid phases ([B]final_200 °C = 55.61 μg/g; DS/FB200 °C = 13.42) and a preferential uptake of the lighter 10B isotope (Δ11BS-F = -3.46‰). Despite a low reaction turnover at 100 °C (<12%), considerable amounts of B were again incorporated into solid phases ([B]final_100 °C = 25.33 μg/g; DS/FB100 °C = 24.2) with even a larger isotope fractionation factor (Δ11BS-F = -9.97‰). While magnitude of isotope fraction appears anti-correlated with temperature, we argue for an overall attenuation of the isotopic effect through changes in B speciation in saline solutions (NaB(OH)4(aq) and B(OH)3Cl-) as well as variable B fixation and fractionation for different serpentinization product minerals (brucite, chrysotile). Breakdown of the Li-rich olivine and limited Li incorporation into product mineral phases resulted in an overall lower Li content of the final solid phase assemblage at 200 °C ([Li]final_200 °C = 0.77 μg/g; DS/FLi200 °C = 1.58). First order changes in Li isotopic compositions were defined by mixing of two isotopically distinct sources i.e. the fresh olivine and the fluid rather than by equilibrium isotope fraction. At 200 °C primary olivine is dissolved, releasing its Li budget into the fluid which shifts towards a lower δ7LiF of +38.62‰. Newly formed serpentine minerals (δ7LiS = +30.58‰) incorporate fluid derived Li with a minor preference of the 6Li isotope. At 100 °C Li enrichment of secondary phases exceeded Li release by olivine breakdown ([Li]final_100 °C = 2.10 μg/g; DS/FLi100 °C = 11.3) and it was accompanied by preferential incorporation of heavier 7Li isotope that might be due to incorporation of a 7Li enriched fluid fraction into chrysotile nanotubes.

SpaceWire: IP, Components, Development Support and Test Equipment

NASA Astrophysics Data System (ADS)

Parkes, S.; McClements, C.; Mills, S.; Martin, I.

SpaceWire is a communications network for use onboard spacecraft. It is designed to connect high data-rate sensors, large solid-state memories, processing units and the downlink telemetry subsystem providing an integrated data-handling network. SpaceWire links are serial, high-speed (2 Mbits/sec to 400 Mbits/sec), bi-directional, full-duplex, pointto- point data links which connect together SpaceWire equipment. Application information is sent along a SpaceWire link in discrete packets. Control and time information can also be sent along SpaceWire links. SpaceWire is defined in the ECSS-E50-12A standard [1]. With the adoption of SpaceWire on many space missions the ready availability of intellectual property (IP) cores, components, software drivers, development support, and test equipment becomes a major issue for those developing satellites and their electronic subsystems. This paper describes the work being done at the University of Dundee and STAR-Dundee Ltd with ESA, BNSC and internal funding to make these essential items available. STAR-Dundee is a spin-out company of the University of Dundee set up specifically to support users of SpaceWire.

Effect Of Low External Flow On Flame Spreading Over ETFE Insulated Wire Under Microgravity

NASA Technical Reports Server (NTRS)

Nishizawa, Katsuhiro; Fujita, Osamu; Ito, Kenichi; Kikuchi, Masao; Olson, Sandra L.; Kashiwagi, Takashi

2003-01-01

Fire safety is one of the most important issues for manned space missions. A likely cause of fires in spacecraft is wire insulation combustion in electrical system. Regarding the wire insulation combustion it important to know the effect of low external flow on the combustion because of the presence of ventilation flow in spacecraft. Although, there are many researches on flame spreading over solid material at low external flows under microgravity, research dealing with wire insulation is very limited. An example of wire insulation combustion in microgravity is the Space Shuttle experiments carried out by Greenberg et al. However, the number of experiments was very limited. Therefore, the effect of low flow velocity is still not clear. The authors have reported results on flame spreading over ETFE (ethylene - tetrafluoroetylene) insulated wire in a quiescent atmosphere in microgravity by 10 seconds drop tower. The authors also performed experiments of polyethylene insulated nichrom wire combustion in low flow velocity under microgravity. The results suggested that flame spread rate had maximum value in low flow velocity condition. Another interesting issue is the effect of dilution gas, especially CO2, which is used for fire extinguisher in ISS. There are some researches working on dilution gas effect on flame spreading over solid material in quiescent atmosphere in microgravity. However the research with low external flow is limited and, of course, the research discussing a relation of the appearance of maximum wire flammability in low flow velocity region with different dilution gas cannot be found yet. The present paper, therefore, investigates the effect of opposed flow with different dilution gas on flame spreading over ETFE insulated wire and change in the presence of the maximum flammability depending on the dilution gas type is discussed within the limit of microgravity time given by ground-based facility.

Facile preparation of multifunctional carbon nanotube/magnetite/polyaniline nanocomposite offering a strong option for efficient solid-phase microextraction coupled with GC-MS for the analysis of phenolic compounds.

PubMed

Tafazoli, Zahra; Azar, Parviz Aberoomand; Tehrani, Mohammad Saber; Husain, Syed Waqif

2018-04-20

The aim of this study the synthesis of a highly efficient organic-inorganic nanocomposite. In this research, the carbon nanotube/magnetite/polyaniline nanocomposite was successfully prepared through a facile route. Monodisperse magnetite nanospheres were prepared through the coprecipitation route, and polyaniline nanolayer as a modified shell with a high surface area was synthesized by an in situ growth route and characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction and energy dispersive X-ray spectroscopy. The prepared nanocomposite was immobilized on a stainless-steel wire for the fabrication of the solid-phase microextraction fiber. The combination of headspace solid-phase microextraction using carbon nanotube/magnetite/polyaniline nanocomposite fiber with gas chromatography and mass spectrometry can achieve a low limit of detection and can be applied to determine phenolic compounds in water samples. The effects of the extraction and desorption parameters including extraction temperature and time, ionic strength, stirring rate, pH, and desorption temperature and time have been studied. Under the optimum conditions, the dynamic linear range was 0.01-500 ng mL -1 and the limits of detection of phenol, 4-chlorophenol, 2,6-dichlorophenol, and 2,4,6-trichlorophenol were the lowest (0.008 ng mL -1 ) for three times. The coefficient of determination of all calibration curves was more than 0.990. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Wire Array Solar Cells: Fabrication and Photoelectrochemical Studies

NASA Astrophysics Data System (ADS)

Spurgeon, Joshua Michael

Despite demand for clean energy to reduce our addiction to fossil fuels, the price of these technologies relative to oil and coal has prevented their widespread implementation. Solar energy has enormous potential as a carbon-free resource but is several times the cost of coal-produced electricity, largely because photovoltaics of practical efficiency require high-quality, pure semiconductor materials. To produce current in a planar junction solar cell, an electron or hole generated deep within the material must travel all the way to the junction without recombining. Radial junction, wire array solar cells, however, have the potential to decouple the directions of light absorption and charge-carrier collection so that a semiconductor with a minority-carrier diffusion length shorter than its absorption depth (i.e., a lower quality, potentially cheaper material) can effectively produce current. The axial dimension of the wires is long enough for sufficient optical absorption while the charge-carriers are collected along the shorter radial dimension in a massively parallel array. This thesis explores the wire array solar cell design by developing potentially low-cost fabrication methods and investigating the energy-conversion properties of the arrays in photoelectrochemical cells. The concept was initially investigated with Cd(Se, Te) rod arrays; however, Si was the primary focus of wire array research because its semiconductor properties make low-quality Si an ideal candidate for improvement in a radial geometry. Fabrication routes for Si wire arrays were explored, including the vapor-liquid-solid growth of wires using SiCl4. Uniform, vertically aligned Si wires were demonstrated in a process that permits control of the wire radius, length, and spacing. A technique was developed to transfer these wire arrays into a low-cost, flexible polymer film, and grow multiple subsequent arrays using a single Si(111) substrate. Photoelectrochemical measurements on Si wire array/polymer composite films showed that their energy-conversion properties were comparable to those of an array attached to the growth substrate. High quantum efficiencies were observed relative to the packing density of the wires, particularly with illumination at high angles of incidence. The results indicate that an inexpensive, solid-state Si wire array solar cell is possible, and a plan is presented to develop one.

Nanostructured copper-coated solid-phase microextraction fiber for gas chromatographic analysis of dibutyl phthalate and diethylhexyl phthalate environmental estrogens.

PubMed

Feng, Juanjuan; Sun, Min; Bu, Yanan; Luo, Chuannan

2015-01-01

A novel nanostructured copper-based solid-phase microextraction fiber was developed and applied for determining the two most common types of phthalate environmental estrogens (dibutyl phthalate and diethylhexyl phthalate) in aqueous samples, coupled to gas chromatography with flame ionization detection. The copper film was coated onto a stainless-steel wire via an electroless plating process, which involved a surface activation process to improve the surface properties of the fiber. Several parameters affecting extraction efficiency such as extraction time, extraction temperature, ionic strength, desorption temperature, and desorption time were optimized by a factor-by-factor procedure to obtain the highest extraction efficiency. The as-established method showed wide linear ranges (0.05-250 μg/L). Precision of single fiber repeatability was <7.0%, and fiber-to-fiber repeatability was <10%. Limits of detection were 0.01 μg/L. The proposed method exhibited better or comparable extraction performance compared with commercial and other lab-made fibers, and excellent thermal stability and durability. The proposed method was applied successfully for the determination of model analytes in plastic soaking water. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Preliminary investigation on the use of low current pulsed power Z-pinch plasma devices for the study of early stage plasma instabilities

NASA Astrophysics Data System (ADS)

Kaselouris, E.; Dimitriou, V.; Fitilis, I.; Skoulakis, A.; Koundourakis, G.; Clark, E. L.; Chatzakis, J.; Bakarezos, Μ; Nikolos, I. K.; Papadogiannis, N. A.; Tatarakis, M.

2018-01-01

This article addresses key features for the implementation of low current pulsed power plasma devices for the study of matter dynamics from the solid to the plasma phase. The renewed interest in such low current plasma devices lies in the need to investigate methods for the mitigation of prompt seeding mechanisms for the generation of plasma instabilities. The low current when driven into thick wires (skin effect mode) allows for the simultaneous existence of all phases of matter from solid to plasma. Such studies are important for the concept of inertial confinement fusion where the mitigation of the instability seeding mechanisms arising from the very early moments within the target’s heating is of crucial importance. Similarly, in the magnetized liner inertial fusion concept it is an open question as to how much surface non-uniformity correlates with the magneto-Rayleigh-Taylor instability, which develops during the implosion. This study presents experimental and simulation results, which demonstrate that the use of low current pulsed power devices in conjunction with appropriate diagnostics can be important for studying seeding mechanisms for the imminent generation of plasma instabilities in future research.

Preparation and characterization of sodium dodecyl sulfate doped polypyrrole solid phase micro extraction fiber and its application to endocrine disruptor pesticide analysis.

PubMed

Korba, Korcan; Pelit, Levent; Pelit, Füsun Okçu; Ozdokur, K Volkan; Ertaş, Hasan; Eroğlu, Ahmet E; Ertaş, F Nil

2013-06-15

A robust in house solid-phase micro extraction (SPME) surface has been developed for the headspace (HS)-SPME determination of endocrine disruptor pesticides, namely, Chlorpyrifos, Penconazole, Procymidone, Bromopropylate and Lambda-Cyhalothrin in wine sample by using sodium dodecylsulfate doped polypyrrole SPME fiber. Pyrrole monomer was electrochemically polymerized on a stainless steel wire in laboratory conditions in virtue of diminishing the cost and enhancing the analyte retention on its surface to exert better selectivity and hence the developed polymerized surface could offer to analyst to exploit it as a fiber in headspace SPME analysis. The parameters, mainly, adsorption temperature and time, desorption temperature, stirring rate and salt amount were optimized to be as 70°C and 45min, 200°C, 600rpm and 10gL(-1), respectively. Limit of detection was estimated in the range of 0.073-1.659ngmL(-1) for the pesticides studied. The developed method was applied in to red wine sample with acceptable recovery values (92-107%) which were obtained for these selected pesticides. Copyright © 2013 Elsevier B.V. All rights reserved.

Preparation of sulfonated graphene/polypyrrole solid-phase microextraction coating by in situ electrochemical polymerization for analysis of trace terpenes.

PubMed

Zhang, Chengjiang; Zhang, Zhuomin; Li, Gongke

2014-06-13

In this study, a novel sulfonated graphene/polypyrrole (SG/PPy) solid-phase microextraction (SPME) coating was prepared and fabricated on a stainless-steel wire by a one-step in situ electrochemical polymerization method. Crucial preparation conditions were optimized as polymerization time of 15min and SG doping amount of 1.5mg/mL. SG/PPy coating showed excellent thermal stability and mechanical durability with a long lifespan of more than 200 stable replicate extractions. SG/PPy coating demonstrated higher extraction selectivity and capacity to volatile terpenes than commonly-used commercial coatings. Finally, SG/PPy coating was practically applied for the analysis of volatile components from star anise and fennel samples. The majority of volatile components identified were terpenes, which suggested the ultra-high extraction selectivity of SG/PPy coating to terpenes during real analytical projects. Four typical volatile terpenes were further quantified to be 0.2-27.4μg/g from star anise samples with good recoveries of 76.4-97.8% and 0.1-1.6μg/g from fennel samples with good recoveries of 80.0-93.1%, respectively. Copyright © 2014 Elsevier B.V. All rights reserved.

77 FR 50713 - Steel Wire Garment Hangers From Taiwan and Vietnam; (Corrected Notice) Scheduling of the Final...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-22

...)] Steel Wire Garment Hangers From Taiwan and Vietnam; (Corrected Notice) Scheduling of the Final Phase of... the United States is materially retarded, by reason of subsidized imports from Vietnam of steel wire garment hangers and less- than-fair-value imports from Taiwan and Vietnam of steel wire garment hangers...

High strength, low carbon, dual phase steel rods and wires and process for making same

DOEpatents

Thomas, Gareth; Nakagawa, Alvin H.

1986-01-01

A high strength, high ductility, low carbon, dual phase steel wire, bar or rod and process for making the same is provided. The steel wire, bar or rod is produced by cold drawing to the desired diameter in a single multipass operation a low carbon steel composition characterized by a duplex microstructure consisting essentially of a strong second phase dispersed in a soft ferrite matrix with a microstructure and morphology having sufficient cold formability to allow reductions in cross-sectional area of up to about 99.9%. Tensile strengths of at least 120 ksi to over 400 ksi may be obtained.

Reaction paths and equilibrium end-points in solid-solution aqueous-solution systems

USGS Publications Warehouse

Glynn, P.D.; Reardon, E.J.; Plummer, Niel; Busenberg, E.

1990-01-01

Equations are presented describing equilibrium in binary solid-solution aqueous-solution (SSAS) systems after a dissolution, precipitation, or recrystallization process, as a function of the composition and relative proportion of the initial phases. Equilibrium phase diagrams incorporating the concept of stoichiometric saturation are used to interpret possible reaction paths and to demonstrate relations between stoichiometric saturation, primary saturation, and thermodynamic equilibrium states. The concept of stoichiometric saturation is found useful in interpreting and putting limits on dissolution pathways, but there currently is no basis for possible application of this concept to the prediction and/ or understanding of precipitation processes. Previously published dissolution experiments for (Ba, Sr)SO4 and (Sr, Ca)C??O3orth. solids are interpreted using equilibrium phase diagrams. These studies show that stoichiometric saturation can control, or at least influence, initial congruent dissolution pathways. The results for (Sr, Ca)CO3orth. solids reveal that stoichiometric saturation can also control the initial stages of incongruent dissolution, despite the intrinsic instability of some of the initial solids. In contrast, recrystallisation experiments in the highly soluble KCl-KBr-H2O system demonstrate equilibrium. The excess free energy of mixing calculated for K(Cl, Br) solids is closely modeled by the relation GE = ??KBr??KClRT[a0 + a1(2??KBr-1)], where a0 is 1.40 ?? 0.02, a1, is -0.08 ?? 0.03 at 25??C, and ??KBr and ??KCl are the mole fractions of KBr and KCl in the solids. The phase diagram constructed using this fit reveals an alyotropic maximum located at ??KBr = 0.676 and at a total solubility product, ???? = [K+]([Cl-] + [Br-]) = 15.35. ?? 1990.

A TASER conducted electrical weapon with cardiac biomonitoring capability: Proof of concept and initial human trial.

PubMed

Stopyra, Jason P; Ritter, Samuel I; Beatty, Jennifer; Johnson, James C; Kleiner, Douglas M; Winslow, James E; Gardner, Alison R; Bozeman, William P

2016-10-01

Despite research demonstrating the overall safety of Conducted Electrical Weapons (CEWs), commonly known by the brand name TASER(®), concerns remain regarding cardiac safety. The addition of cardiac biomonitoring capability to a CEW could prove useful and even lifesaving in the rare event of a medical crisis by detecting and analyzing cardiac rhythms during the period immediately after CEW discharge. To combine an electrocardiogram (ECG) device with a CEW to detect and store ECG signals while still allowing the CEW to perform its primary function of delivering an incapacitating electrical discharge. This work was performed in three phases. In Phase 1 standard law enforcement issue CEW cartridges were modified to demonstrate transmission of ECG signals. In Phase 2, a miniaturized ECG recorder was combined with a standard issue CEW and tested. In Phase 3, a prototype CEW with on-board cardiac biomonitoring was tested on human volunteers to assess its ability to perform its primary function of electrical incapacitation. Bench testing demonstrated that slightly modified CEW cartridge wires transmitted simulated ECG signals produced by an ECG rhythm generator and from a human volunteer. Ultimately, a modified CEW incorporating ECG monitoring successfully delivered incapacitating current to human volunteers and successfully recorded ECG signals from subcutaneous CEW probes after firing. An ECG recording device was successfully incorporated into a standard issue CEW without impeding the functioning of the device. This serves as proof-of-concept that safety measures such as cardiac biomonitoring can be incorporated into CEWs and possibly other law enforcement devices. Copyright © 2016 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

Growth and Characterization of Chalcogenide Alloy Nanowires with Controlled Spatial Composition Variation for Optoelectronic Applications

NASA Astrophysics Data System (ADS)

Nichols, Patricia

The energy band gap of a semiconductor material critically influences the operating wavelength of an optoelectronic device. Realization of any desired band gap, or even spatially graded band gaps, is important for applications such as lasers, light-emitting diodes (LEDs), solar cells, and detectors. Compared to thin films, nanowires offer greater flexibility for achieving a variety of alloy compositions. Furthermore, the nanowire geometry permits simultaneous incorporation of a wide range of compositions on a single substrate. Such controllable alloy composition variation can be realized either within an individual nanowire or between distinct nanowires across a substrate. This dissertation explores the control of spatial composition variation in ternary alloy nanowires. Nanowires were grown by the vapor-liquid-solid (VLS) mechanism using chemical vapor deposition (CVD). The gas-phase supersaturation was considered in order to optimize the deposition morphology. Composition and structure were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive x-ray spectroscopy (EDS), and x-ray diffraction (XRD). Optical properties were investigated through photoluminescence (PL) measurements. The chalcogenides selected as alloy endpoints were lead sulfide (PbS), cadmium sulfide (CdS), and cadmium selenide (CdSe). Three growth modes of PbS were identified, which included contributions from spontaneously generated catalyst. The resulting wires were found capable of lasing with wavelengths over 4000 nm, representing the longest known wavelength from a sub-wavelength wire. For CdxPb1-xS nanowires, it was established that the cooling process significantly affects the alloy composition and structure. Quenching was critical to retain metastable alloys with x up to 0.14, representing a new composition in nanowire form. Alternatively, gradual cooling caused phase segregation, which created heterostructures with light emission in both the visible and mid-infrared regimes. The CdSSe alloy system was fully explored for spatial composition variation. CdSxSe1-x nanowires were grown with composition variation across the substrate. Subsequent contact printing preserved the designed composition gradient and led to the demonstration of a variable wavelength photodetector device. CdSSe axial heterostructure nanowires were also achieved. The growth process involved many variables, including a deliberate and controllable change in substrate temperature. As a result, both red and green light emission was detected from single nanowires.

Effects of δ phase and cold drawing ratio on the LCF properties of alloy 718 wire

NASA Astrophysics Data System (ADS)

Jeong, Yong-Kwon; Jo, Chang-Yong; Kim, In-Bae

2000-10-01

The effects of the amount and distribution of δ particles on the low cycle fatigue (LCF) properties of alloy 718 wire were investigated. The amount and distribution of δ particles were controlled by cold drawing followed by a variety of agings. As the cold drawing ratio and aging time at 1116K increased, the well developed granular δ particles increased in amount and their distribution at grain/twin boundaries became more uniform. Regardless of the aging conditions, the LCF life increased as the cold drawing ratio increased. The granular particles precipitated along the grain boundary also improved the LCF life of alloy 718 wire since they inhibited crack propagation. After Merrick heat treatment, 50% of the cold drawn wire displayed lower 698K tensile and yield strength than 30% of the cold drawn wire. This was because the higher strain induced by the cold drawing prior to the first aging at 1116K appeared to promote the precipitation of the δ phase during aging, which has no influence on the strength of the material but has same stoichiometry with the γ phase as Ni3Nb and, as a result, the higher strain precipitated a smaller quantity of γ particles with subsequent aging, which is a major hardening phase of the alloy. Cold drawing also lowered the precipitation temperature of the δ phase.

Phase transformation changes in thermocycled nickel-titanium orthodontic wires.

PubMed

Berzins, David W; Roberts, Howard W

2010-07-01

In the oral environment, orthodontic wires will be subject to thermal fluctuations. The purpose of this study was to investigate the effect of thermocycling on nickel-titanium (NiTi) wire phase transformations. Straight segments from single 27 and 35 degrees C copper NiTi (Ormco), Sentalloy (GAC), and Nitinol Heat Activated (3M Unitek) archwires were sectioned into 5mm segments (n=20). A control group consisted of five randomly selected non-thermocycled segments. The remaining segments were thermocycled between 5 and 55 degrees C with five randomly selected segments analyzed with differential scanning calorimetry (DSC; -100<-->150 degrees C at 10 degrees C/min) after 1000, 5000, and 10,000 cycles. Thermal peaks were evaluated with results analyzed via ANOVA (alpha=0.05). Nitinol HA and Sentalloy did not demonstrate qualitative or quantitative phase transformation behavior differences. Significant differences were observed in some of the copper NiTi transformation temperatures, as well as the heating enthalpy with the 27 degrees C copper NiTi wires (p<0.05). Qualitatively, with increased thermocycling the extent of R-phase in the heating peaks decreased in the 35 degrees C copper NiTi, and an austenite to martensite peak shoulder developed during cooling in the 27 degrees C copper NiTi. Repeated temperature fluctuations may contribute to qualitative and quantitative phase transformation changes in some NiTi wires. Copyright 2010 Academy of Dental Materials. All rights reserved.

Solid-phase supports for the in situ assembly of quantum dot-FRET hybridization assays in channel microfluidics.

PubMed

Tavares, Anthony J; Noor, M Omair; Uddayasankar, Uvaraj; Krull, Ulrich J; Vannoy, Charles H

2014-01-01

Semiconductor quantum dots (QDs) have long served as integral components in signal transduction modalities such as Förster resonance energy transfer (FRET). The majority of bioanalytical methods using QDs for FRET-based techniques simply monitor binding-induced conformational changes. In more recent work, QDs have been incorporated into solid-phase support systems, such as microfluidic chips, to serve as physical platforms in the development of functional biosensors and bioprobes. Herein, we describe a simple strategy for the transduction of nucleic acid hybridization that combines a novel design method based on FRET with an electrokinetically controlled microfluidic technology, and that offers further potential for amelioration of sample-handling issues and for simplification of dynamic stringency control.

Synthesis and photocatalytic degradation study of methylene blue dye under visible light irradiation by Fe1-xBixVO4 solid solutions (0 ≤ x ≤ 1.0)

NASA Astrophysics Data System (ADS)

Bera, Ganesh; Reddy, V. R.; Mal, Priyanath; Das, Pradip; Turpu, G. R.

2018-05-01

The novel hetero-structures Fe1-xBixVO4 solid solutions (0 ≤ x ≤ 1.0) with the two dissimilar end member of FeVO4 - BiVO4, were successfully synthesized by the standard solid state reaction method. The structural and chemical properties of as prepared photo-catalyst samples were characterized by X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR) and UV-visible absorption spectroscopy techniques. It is confirmed from the results of XRD, Raman and FT-IR that FeVO4 and BiVO4 are in triclinic (space group P-1 (2)) and monoclinic (space group I2/b (15)) phases respectively. The Bi incorporation into Fe site of FeVO4 emerges as hetero-structures of both the end members of the solid solutions. In addition, the photocatalytic activity in the degradation of methylene blue (MB) dye under visible light irradiation was carried out through UV-visible spectroscopy measurement of photo-catalysts FeVO4, BiVO4 and mixed phases of both photo-catalyst. The results indicate that under visible light irradiation the photocatalytic activity of mixed phases were very effective and higher than the both single phases of the solid solutions. The composition x= 0.25 exhibits an excellent photocatalytic property for the degradation of MB solution under visible light irradiation rather than other.

Evaluating Thermally Damaged Polyimide Insulated Wiring (MIL-W-81381) with Ultrasound

NASA Technical Reports Server (NTRS)

Madaras, Eric I.; Anastasi, Robert F.

2002-01-01

A series of experiments to investigate the use of ultrasound for measuring wire insulation have been conducted. Initial laboratory tests were performed on MIL-W-81381/7,/12, and /21 aviation wire, a wire that has polyimide (Kapton Registered Trademark) layers for insulation. Samples of this wiring were exposed to 370C temperatures for different periods of time to induce a range of thermal damage. For each exposure, 12 samples of each gauge (12, 16, and 20 gauges) were processed. The velocity of the lowest order axisymmetric ultrasonic guided mode, a mode that is sensitive to the geometry and stiffness of the wire conductor and insulation, was measured. The phase velocity for the 20-gauge MIL-W-81381/7 wire had a baseline value of 3023 +/- 78 m/s. After exposure to the high temperatures, the wire's phase velocity rapidly increased, and reached an asymptotic value of 3598 +/- 20 m/s after 100 hours exposure. Similar behavior was measured for the 16 gauge MIL-W-81381/21 wire and 12 gauge MIL-W-81381/12 wire which had baseline values of 3225 +/- 22 m/s and 3403 +/- 33 m/s respectively, and reached asymptotic values of 3668 +/- 19 m/s, and 3679 +/- 42 m/s respectively. These measured velocity changes represent changes of 19, 14, and 8 percent respectively for the 20, 16, and 12 gauge wires. Finally, some results for a wire with an ethylene tetrafluoroethylene insulation are reported. Qualitatively similar behaviors are noted ultrasonically.

Development of a HTSMA-Actuated Surge Control Rod for High-Temperature Turbomachinery Applications

NASA Technical Reports Server (NTRS)

Padula, Santo, II; Noebe, Ronald; Bigelow, Glen; Culley, Dennis; Stevens, Mark; Penney, Nicholas; Gaydosh, Darrell; Quackenbush, Todd; Carpenter, Bernie

2007-01-01

In recent years, a demand for compact, lightweight, solid-state actuation systems has emerged, driven in part by the needs of the aeronautics industry. However, most actuation systems used in turbomachinery require not only elevated temperature but high-force capability. As a result, shape memory alloy (SMA) based systems have worked their way to the forefront of a short list of viable options to meet such a technological challenge. Most of the effort centered on shape memory systems to date has involved binary NiTi alloys but the working temperatures required in many aeronautics applications dictate significantly higher transformation temperatures than the binary systems can provide. Hence, a high temperature shape memory alloy (HTSMA) based on NiTiPdPt, having a transformation temperature near 300 C, was developed. Various thermo-mechanical processing schemes were utilized to further improve the dimensional stability of the alloy and it was later extruded/drawn into wire form to be more compatible with envisioned applications. Mechanical testing on the finished wire form showed reasonable work output capability with excellent dimensional stability. Subsequently, the wire form of the alloy was incorporated into a benchtop system, which was shown to provide the necessary stroke requirements of approx.0.125 inches for the targeted surge-control application. Cycle times for the actuator were limited to 4 seconds due to control and cooling constraints but this cycle time was determined to be adequate for the surge control application targeted as the primary requirement was initial actuation of a surge control rod, which could be completed in approximately one second.

Approximating the Sachdev-Ye-Kitaev model with Majorana wires

NASA Astrophysics Data System (ADS)

Chew, Aaron; Essin, Andrew; Alicea, Jason

The Sachdev-Ye-Kitaev (SYK) model describes a large collection of Majorana fermions coupled via random, `all-to-all' four-fermion interactions. This model enjoys broad interdisciplinary interest because it provides a solvable realization of holography in 0+1 dimensions, exhibits unusual spectral and thermodynamic properties, and shares deep connections to chaos and black holes. We propose a solid-state implementation of the SYK Hamiltonian that employs quantum dots coupled to arrays of topological superconductors hosting Majorana end-states. All-to-all four-Majorana couplings are mediated by interactions in the dot, while the randomness originates from disorder in the hoppings between the Majorana modes and dot levels. Using perturbation theory and explicit numerics, we study the properties of the dot-wire array system under various experimental conditions. Interestingly, our setup not only allows exploration of SYK physics, but also provides a controlled testbed for interaction effects on the topological classification of fermionic phases. Supported by the National Science Foundation (DMR-1341822), Institute for Quantum Information and Matter, and Walter Burke Institute at Caltech. AC gratefully acknowledges support from the Dominic Orr Fellowship.

Development of clinical dosage forms for a poorly water-soluble drug II: formulation and characterization of a novel solid microemulsion preconcentrate system for oral delivery of a poorly water-soluble drug.

PubMed

Li, Ping; Hynes, Sara R; Haefele, Thomas F; Pudipeddi, Madhu; Royce, Alan E; Serajuddin, Abu T M

2009-05-01

The solution of a poorly water-soluble drug in a liquid lipid-surfactant mixture, which served as a microemulsion preconcentrate, was converted into a solid form by incorporating it in a solid polyethylene glycol (PEG) matrix. The solid microemulsion preconcentrates thus formed consisted of Capmul PG8 (propylene glycol monocaprylate) as oil, Cremophor EL (polyoxyl 35 castor oil) as surfactant, and hydrophilic polymer PEG 3350 as solid matrix. The drug (aqueous solubility: 0.17 microg/mL at pH 1-8 and 25 degrees C) was dissolved in a melt of the mixture at 65-70 degrees C and then the hot solution was filled into hard gelatin capsules; the liquid gradually solidified upon cooling below 55 degrees C. The solid system was characterized by differential scanning calorimetry (DSC), scanning electron microscopy (SEM), confocal Raman microscopy (CRM), and the dispersion testing in water. It was confirmed that a solid microemulsion preconcentrate is a two-phase system, where clusters of crystalline PEG 3350 formed the solid structure (m.p. 55-60 degrees C) and the liquid microemulsion preconcentrate dispersed in between PEG 3350 crystals as a separate phase. The drug remained dissolved in the liquid phase. In vitro release testing showed that the preconcentrate dispersed readily in water forming a microemulsion with the drug dissolved in the oil particles (<150 nm) and the presence of PEG 3350 did not interfere with the process of self-microemulsification.

Influence of flooring type during transport and holding on bacteria recovery from broiler carcass rinses before and after defeathering.

PubMed

Buhr, R J; Cason, J A; Dickens, J A; Hinton, A; Ingram, K D

2000-03-01

Four trials were conducted to determine whether conventional solid or elevated wire mesh flooring, during transport and holding of broilers prior to slaughter, influenced the number of bacteria recovered from feathered and defeathered carcasses. After 4 h off feed, 7-wk-old broilers were placed at commercial density into a modified commercial transport dump-coop on either fiberglass sheeting or 2.54x2.54 cm wire mesh flooring that allowed feces to fall through. Broilers were transported for 1 h and then held for 13 h under a covered shed before processing. Broilers were killed by electrocution, and the vents were plugged to prevent escape of feces. External carcass rinses were obtained twice (from the same carcass) from eight broilers per flooring treatment per trial, before scalding and defeathering and again after defeathering and removal of the head and feet. Greater numbers of total aerobes, coliforms, and Escherichia coli were recovered from feathered carcasses than from defeathered carcasses. Campylobacter count was also less for defeathered than feathered carcasses from the solid flooring treatment but did not significantly decrease following defeathering of carcasses from the wire flooring. The incidence of Campylobacter-positive carcasses was reduced following defeathering for both flooring treatments, but the percentage of Salmonellae-positive carcasses remained constant. Coliform (log10 6.20 vs. 5.63 cfu/mL of rinse) and E. coli (log10 5.93 vs. 5.36) counts in the feathered rinses were significantly higher for the solid flooring compared with wire flooring, respectively. After defeathering, the number of coliforms (log10 3.12) and E. coli (log10 2.91) recovered did not differ between flooring treatments. Aerobic plate count (log10 7.06 and 4.02), Campylobacter count (log10 2.49 and 1.80), and the incidence of Campylobacter-positive (44 and 11%) and Salmonellae-positive (52 and 50%) carcasses for feathered and defeathered rinses, respectively, did not differ between flooring treatments. These results indicate that although broilers transported and held on solid flooring had noticeably dirtier breast feathers and higher coliform and E. coli counts prior to scalding and defeathering, bacteria recovery from external carcass rinses did not differ between the solid and wire flooring treatments after defeathering.

A Novel Portable Absolute Transient Hot-Wire Instrument for the Measurement of the Thermal Conductivity of Solids

NASA Astrophysics Data System (ADS)

Assael, Marc J.; Antoniadis, Konstantinos D.; Metaxa, Ifigeneia N.; Mylona, Sofia K.; Assael, John-Alexander M.; Wu, Jiangtao; Hu, Miaomiao

2015-11-01

A new portable absolute Transient Hot-Wire instrument for measuring the thermal conductivity of solids over a range of 0.2 { W}{\\cdot }m^{-1}{\\cdot }{K}^{-1} to 4 { W}{\\cdot }m^{-1}{\\cdot }{K}^{-1} is presented. The new instrument is characterized by three novelties: (a) an innovative two-wires sensor which provides robustness and portability, while at the same time employs a soft silicone layer to eliminate the effect of the contact resistance between the wires and the sample, (b) a newly designed compact portable printed electronic board employing an FPGA architecture CPU to the control output voltage and data processing—the new board replaces the traditional, large in size Wheatstone-type bridge system required to perform the experimental measurements, and (c) a cutting-edge software suite, developed for the mesh describing the structure of the sensor, and utilizing the Finite Elements Method to model the heat flow. The estimation of thermal conductivity is modeled as a minimization problem and is solved using Bayesian Optimization. Our revolutionizing proposed methodology exhibits radical speedups of up to × 120, compared to previous approaches, and considerably reduces the number of simulations performed, achieving convergence only in a few minutes. The new instrument was successfully employed to measure, at room temperature, the thermal conductivity of two thermal conductivity reference materials, Pyroceram 9606 and Pyrex 7740, and two possible candidate glassy solids, PMMA and BK7, with an absolute low uncertainty of 2 %.

Description and Flight Test Results of the NASA F-8 Digital Fly-by-Wire Control System

NASA Technical Reports Server (NTRS)

1975-01-01

A NASA program to develop digital fly-by-wire (DFBW) technology for aircraft applications is discussed. Phase I of the program demonstrated the feasibility of using a digital fly-by-wire system for aircraft control through developing and flight testing a single channel system, which used Apollo hardware, in an F-8C airplane. The objective of Phase II of the program is to establish a technology base for designing practical DFBW systems. It will involve developing and flight testing a triplex digital fly-by-wire system using state-of-the-art airborne computers, system hardware, software, and redundancy concepts. The papers included in this report describe the Phase I system and its development and present results from the flight program. Man-rated flight software and the effects of lightning on digital flight control systems are also discussed.

49 CFR 393.7 - Matter incorporated by reference.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Specification for Strapping, Flat Steel and Seals, American Society for Testing and Materials (ASTM), D3953-97, February 1998, incorporation by reference approved for § 393.104(e). (19) Welded Steel Chain Specifications... Association, WSTDA-T1, 1998, incorporation by reference approved for § 393.104(e). (21) Wire Rope Users Manual...

49 CFR 393.7 - Matter incorporated by reference.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Specification for Strapping, Flat Steel and Seals, American Society for Testing and Materials (ASTM), D3953-97, February 1998, incorporation by reference approved for § 393.104(e). (19) Welded Steel Chain Specifications... Association, WSTDA-T1, 1998, incorporation by reference approved for § 393.104(e). (21) Wire Rope Users Manual...

Raman Analysis of Dilute Aqueous Samples by Localized Evaporation of Submicroliter Droplets on the Tips of Superhydrophobic Copper Wires.

PubMed

Cheung, Melody; Lee, Wendy W Y; McCracken, John N; Larmour, Iain A; Brennan, Steven; Bell, Steven E J

2016-04-19

Raman analysis of dilute aqueous solutions is normally prevented by their low signal levels. A very general method to increase the concentration to detectable levels is to evaporate droplets of the sample to dryness, creating solid deposits which are then Raman probed. Here, superhydrophobic (SHP) wires with hydrophilic tips have been used as supports for drying droplets, which have the advantage that the residue is automatically deposited at the tip. The SHP wires were readily prepared in minutes using electroless galvanic deposition of Ag onto copper wires followed by modification with a polyfluorothiol (3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluoro-1-decanethiol, HDFT). Cutting the coated wires with a scalpel revealed hydrophilic tips which could support droplets whose maximum size was determined by the wire diameter. Typically, 230 μm wires were used to support 0.6 μL droplets. Evaporation of dilute melamine droplets gave solid deposits which could be observed by scanning electron microscopy (SEM) and Raman spectroscopy. The limit of detection for melamine using a two stage evaporation procedure was 1 × 10(-6) mol dm(-3). The physical appearance of dried droplets of sucrose and glucose showed that the samples retained significant amounts of water, even under high vacuum. Nonetheless, the Raman detection limits of sucrose and glucose were 5 × 10(-4) and 2.5 × 10(-3) mol dm(-3), respectively, which is similar to the sensitivity reported for surface-enhanced Raman spectroscopy (SERS) detection of glucose. It was also possible to quantify the two sugars in mixtures at concentrations which were similar to those found in human blood through multivariate analysis.

Nickel distribution and isotopic fractionation in a Brazilian lateritic regolith: Coupling Ni isotopes and Ni K-edge XANES

NASA Astrophysics Data System (ADS)

Ratié, G.; Garnier, J.; Calmels, D.; Vantelon, D.; Guimarães, E.; Monvoisin, G.; Nouet, J.; Ponzevera, E.; Quantin, C.

2018-06-01

Ultramafic (UM) rocks are known to be nickel (Ni) rich and to weather quickly, which makes them a good candidate to look at the Ni isotope systematics during weathering processes at the Earth's surface. The present study aims at identifying the Ni solid speciation and discussing the weathering processes that produce Ni isotope fractionation in two deep laterite profiles under tropical conditions (Barro Alto, Goiás State, Brazil). While phyllosilicates and to a lower extent goethite are the main Ni-bearing phases in the saprolitic part of the profile, iron (Fe) oxides dominate the Ni budget in the lateritic unit. Nickel isotopic composition (δ60Ni values) has been measured in each unit of the regolith, i.e., rock, saprock, saprolite and laterite (n = 52). δ60Ni varies widely within the two laterite profiles, from -0.10 ± 0.05‰ to 1.43 ± 0.05‰, showing that significant Ni isotope fractionation occurs during the weathering of UM rocks. Overall, our results show that during weathering, the solid phase is depleted in heavy Ni isotopes due to the preferential sorption and incorporation of light Ni isotopes into Fe oxides; the same mechanisms likely apply to the incorporation of Ni into phyllosilicates (type 2:1). However, an isotopically heavy Ni pool is observed in the solid phase at the bottom of the saprolitic unit. This feature can be explained by two hypotheses that are not mutually exclusive: (i) a depletion in light Ni isotopes during the first stage of weathering due to the preferential dissolution of light Ni-containing minerals, and (ii) the sorption or incorporation of isotopically heavy Ni carried by percolating waters (groundwater samples have δ60Ni of 2.20 and 2.27‰), that were enriched in heavy Ni isotopes due to successive weathering processes in the overlying soil and laterite units.

Computers Take Flight: A History of NASA's Pioneering Digital Fly-By-Wire Project

NASA Technical Reports Server (NTRS)

Tomayko, James E.

2000-01-01

An overview of the NASA F-8 Fly-by Wire project is presented. The project made two significant contributions to the new technology: (1) a solid design base of techniques that work and those that do not, and (2) credible evidence of good flying qualities and the ability of such a system to tolerate real faults and to continue operation without degradation. In 1972 the F-8C aircraft used in the program became he first digital fly-by-wire aircraft to operate without a mechanical backup system.

Thermophysical Properties of Five Industrial Steels in the Solid and Liquid Phase

NASA Astrophysics Data System (ADS)

Wilthan, B.; Schützenhöfer, W.; Pottlacher, G.

2017-07-01

The need for characterization of thermophysical properties of steel was addressed in the FFG-Bridge Project 810999 in cooperation with our partner from industry, Böhler Edelstahl GmbH & Co KG. To optimize numerical simulations of production processes such as plastic deformation or remelting, additional and more accurate thermophysical property data were necessary for the group of steels under investigation. With the fast ohmic pulse heating circuit system and a commercial high-temperature Differential Scanning Calorimeter at Graz University of Technology, we were able to measure the temperature-dependent specific electrical resistivity and specific enthalpy for a set of five high alloyed steels: E105, M314, M315, P800, and V320 from room temperature up into the liquid phase. The mechanical properties of those steels make sample preparation an additional challenge. The described experimental approach typically uses electrically conducting wire-shaped specimen with a melting point high enough for the implemented pyrometric temperature measurement. The samples investigated here are too brittle to be drawn as wires and could only be cut into rectangular specimen by Electrical Discharge Machining. Even for those samples all electrical signals and the temperature signal can be recorded with proper alignment of the pyrometer. For each material under investigation, a set of data including chemical composition, solidus and liquidus temperature, enthalpy, electrical resistivity, and thermal diffusivity as a function of temperature will be reported.

Disposal of metal fragments released during polycrystalline slicing by multi-wire saw

NASA Astrophysics Data System (ADS)

Boutouchent-Guerfi, N.; Drouiche, N.; Medjahed, S.; Ould-Hamou, M.; Sahraoui, F.

2016-08-01

The environmental and economic impacts linked with solar systems are largely based on discharges of slurry generated during the various stages of sawing and cutting ingots. These discharges into the environment are subject to the general regulations on hazardous and special industrial waste disposal. Therefore, they should not be abandoned or burned in open air. The cutting of Silicon ingots leads to the production of Silicon wafers additional costs, losing more than 30% of Silicon material. Abrasive grains (Silicon Carbide) trapped between the wire and the block of Silicon need to be removed by various mechanisms to be later evacuated by slurry fragments. In the interest of decreasing operational costs during polycrystalline ingot slicing at Semiconductors Research Center, and, avoid environmental problems; it is necessary to recover the solar grade Silicon from the Silicon sawing waste. For this reason, the removal of metal fragments has become a preliminary requirement to regenerate the slurry; in addition, the solid phase needs to be separated from the liquid phase after the dissolution PEG with the solvent. In the present study, magnetic separation and centrifugation methods were adopted for metals removal, followed by the analysis of some operating parameters such as: washing time, pH, and initial concentration of Silicon. Finally, analytical, morphological and basic methods were performed in order to evaluate the efficiency of the process undertaken.

Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transport project: Program review

NASA Technical Reports Server (NTRS)

1986-01-01

This report summarizes the Integrated Application of Active Controls (IAAC) Technology to an Advanced Subsonic Transport Project, established as one element of the NASA/Boeing Energy Efficient Transport Technology Program. The performance assessment showed that incorporating ACT into an airplane designed to fly approximately 200 passengers approximately 2,000 nmi could yield block fuel savings from 6 to 10 percent at the design range. The principal risks associated with incorporating these active control functions into a commercial airplane are those involved with the ACT system implementation. The Test and Evaluation phase of the IAAC Project focused on the design, fabrication, and test of a system that implemented pitch axis fly-by-wire, pitch axis augmentation, and wing load alleviation. The system was built to be flight worthy, and was planned to be experimentally flown on the 757. The system was installed in the Boeing Digital Avionics Flight Controls Laboratory (DAFCL), where open loop hardware and software tests, and a brief examination of a direct drive valve (DDV) actuation concept were accomplished. The IAAC Project has shown that ACT can be beneficially incorporated into a commercial transport airplane. Based on the results achieved during the testing phase, there appears to be no fundamental reason(s) that would preclude the commercial application of ACT, assuming an appropriate development effort is included.

Effect of Slow External Flow on Flame Spreading over Solid Material: Opposed Spreading over Polyethylene Wire Insulation

NASA Technical Reports Server (NTRS)

Fujita, O.; Nishizawa, K.; Ito, K.; Olson, S. L.; Kashigawa, T.

2001-01-01

The effect of slow external flow on solid combustion is very important from the view of fire safety in space because the solid material in spacecraft is generally exposed to the low air flow for ventilation. Further, the effect of low external flow on fuel combustion is generally fundamental information for industrial combustion system, such as gas turbine, boiler incinerator and so on. However, it is difficult to study the effect of low external flow on solid combustion in normal gravity, because the buoyancy-induced flow strongly disturbs the flow field, especially for low flow velocity. In this research therefore, the effect of slow external flow on opposed flame spreading over polyethylene (PE) wire insulation have been investigated in microgravity. The microgravity environment was provided by Japan Microgravity Center (JAMIC) in Japan and KC-135 at NASA GRC. The tested flow velocity range is 0-30cm/s with different oxygen concentration and inert gas component.

Head space solid phase microextraction based on nano-structured lead dioxide: application to the speciation of volatile organoselenium in environmental and biological samples.

PubMed

Ghasemi, Ensieh; Farahani, Hadi

2012-10-05

A novel and efficient speciation method based on the nano-structured lead dioxide as stationary phase of head space solid phase microextraction combined with gas chromatography mass spectrometry (GC-MS) was developed for the determination of volatile organoselenium compounds (dimethylselenide (DMSe) and dimethyldiselenide (DMDSe)) in different biological and environmental samples. PbO(2) particles with a diameter in the range of 50-70 nm have been grown on platinum wire via elechtrochemical deposition. The effect of different variables on the extraction efficiency was studied simultaneously using an experimental design. The variables of interest in the HS-SPME were condition of coating preparation, desorption time, stirring rate, desorption temperature, ionic strength, time and temperature of extraction. A Plackett-Burman design was performed for screening in order to determine the significant variables affecting the extraction efficiency. Then, the significant factors were optimized by a Box-Behnken design (BBD) and the response surface equations were derived. The detection limit and relative standard deviation (RSD) (n=5, c=50 μgL(-1)) for DMSe were 16 ngL(-1) and 4.3%, respectively. They were also obtained for DMDSe as 11ngL(-1) and 4.6%, respectively. The developed technique was found to be applicable to spiked environmental and biological samples. Copyright © 2012 Elsevier B.V. All rights reserved.

(U) Equation of State and Compaction Modeling for CeO 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fredenburg, David A.; Chisolm, Eric D.

2014-10-20

Recent efforts have focused on developing a solid-liquid and three-phase equation of state (EOS) for CeO 2, while parallel experimental efforts have focused on obtaining high-fidelity Hugoniot measurements on CeO 2 in the porous state. The current work examines the robustness of two CeO 2 SESAME equations of state, a solid-liquid EOS, 96170, and a three-phase EOS, 96171, by validating the EOS against a suite of high-pressure shock compression experiments on initially porous CeO 2. At lower pressures compaction is considered by incorporating a two-term exponential form of the P-compaction model, using three separate definitions for α(P). Simulations are executedmore » spanning the partially compacted and fully compacted EOS regimes over the pressure range 0.5 - 109 GPa. Comparison of calculated Hugoniot results with those obtained experimentally indicate good agreement for all definitions of α(P) with both the solid-liquid and three-phase EOS in the low-pressure compaction regime. At higher pressures the three-phase EOS does a better job at predicting the measured Hugoniot response, though at the highest pressures EOS 96171 predicts a less compliant response than is observed experimentally. Measured material velocity profiles of the shock-wave after it has transmitted through the powder are also compared with those simulated using with solid-liquid and three-phase EOS. Profiles lend insight into limits of the current experimental design, as well as the threshold conditions for the shock-induced phase transition in CeO 2.« less

Flexural Testing of Steel Wire Composite Beams Made with Hardwire (trademark) Unidirectional Tape

DTIC Science & Technology

2003-11-18

Hardwire to carbon fabric in the panels was 85%/15% respectively. The 3XSF Hardwire/fiberglass specimens were made with a 675 yield Type 30 Owens ... Corning glass fiber incorporated into the steel wire cord as shown in Figure 3 in a proprietary co-mingling operation in the cord making process. Ply by

Development of explosively bonded TZM wire reinforced Columbian sheet composites

NASA Technical Reports Server (NTRS)

Otto, H. E.; Carpenter, S. H.

1972-01-01

Methods of producing TZM molybdenum wire reinforced C129Y columbium alloy composites by explosive welding were studied. Layers of TZM molybdenum wire were wound on frames with alternate layers of C129Y columbium alloy foil between the wire layers. The frames held both the wire and foils in place for the explosive bonding process. A goal of 33 volume percent molybdenum wire was achieved for some of the composites. Variables included wire diameter, foil thickness, wire separation, standoff distance between foils and types and amounts of explosive. The program was divided into two phases: (1) development of basic welding parameters using 5 x 10-inch composites, and (2) scaleup to 10 x 20-inch composites.

Mechanical properties of nickel-titanium archwire used in the final treatment phase of Tip-Edge Plus technique: an in vitro study.

PubMed

Shen, Xiao; Sun, Xin-hua; Tian, Hua; Zhang, Chun-bo; Yan, Kuo; Guo, Yong-liang

2013-01-01

As the only active component in final treatment phase of Tip-Edge Plus technique, the activation of nickel-titanium orthodontic archwires is one of the factors that affect the torque expression. It is necessary to evaluate the mechanical properties of the nickel-titanium wire used in the final treatment phase in simulated oral environments to forecast the treatment outcomes. The mechanical properties of 171 thermal nickel-titanium wires of 0.35 mm (0.014-in) in diameters with different deflection of 40 mm in length were investigated with three-point bending test. The samples were divided into 2 groups: as-received and bended groups. In the bended group, samples were divided into 7 subgroups according to the amounts of deflection and named by the canine angulations (-25°, -19°, -13°, -7°, -1°, +5°, +11°). The deflection of wires was made by inserting the wires into the deep tunnel of Tip-Edge Plus brackets positioned in plaster casts with different canine angulations to mimic the use of nickel-titanium wires in the final treatment phase. Immersed the bended group in artificial saliva (pH 6.8) and preserved at 37.0°C. Eight durations of incubation were tested: 1 to 8 weeks. Three analogous samples of each group and subgroups were tested per week. Stiffness (YS:E) and the load-deflection characteristics of unloading plateau section were obtained. Significant changes in specific mechanical properties were observed in long-term immersed and large deflected wires compared with as-received groups. Both immersion time and deflection affected the mechanical properties of wires in the simulated oral environment, and the two factors had synergistic effect. In groups -25°, -19° and -13°, stiffness (YS:E) increased then decreased and average plateau force and ratio of variance decreased then increased correspondingly at specific time. In the final treatment phase of Tip-Edge Plus technique, the mechanical properties of nickel-titanium wire are associated with the using time and amounts of deflection and it may affect treatment outcomes. As the main reason for wire deflection, canine crown angulation plays an important role in the wire performance. It may be wise to focus on the canine crown angulations and using time in clinic with Tip-Edge Plus technique and make proper adjustment to help to make sure the treatment outcomes.

Electrophoretic-like gating used to control metal-insulator transitions in electronically phase separated manganite wires.

PubMed

Guo, Hangwen; Noh, Joo H; Dong, Shuai; Rack, Philip D; Gai, Zheng; Xu, Xiaoshan; Dagotto, Elbio; Shen, Jian; Ward, T Zac

2013-08-14

Electronically phase separated manganite wires are found to exhibit controllable metal-insulator transitions under local electric fields. The switching characteristics are shown to be fully reversible, polarity independent, and highly resistant to thermal breakdown caused by repeated cycling. It is further demonstrated that multiple discrete resistive states can be accessed in a single wire. The results conform to a phenomenological model in which the inherent nanoscale insulating and metallic domains are rearranged through electrophoretic-like processes to open and close percolation channels.

Development of automatic through-insulation welding for microelectric interconnections

NASA Technical Reports Server (NTRS)

Arnett, J. C.

1972-01-01

The capability to automatically route, remove insulation from, and weld small-diameter solid conductor wire is presented. This would facilitate the economical small-quantity production of complex miniature electronic assemblies. An engineering model of equipment having this capability was developed and evaluated. Whereas early work in the use of welded magnet wire interconnections was concentrated on opposed electrode systems, and generally used heat to melt the wire insulation, the present method is based on a concentric electrode system and a wire feed system which splits the insulation by application of pressure prior to welding. The work deals with the design, fabrication, and evaluation testing of an improved version of this concentric electrode system. Two different approaches to feeding the wire to the concentric electrodes were investigated. It was concluded that the process is feasible for the interconnection of complex miniature electronic assemblies.

Wire constructions of Abelian topological phases in three or more dimensions

NASA Astrophysics Data System (ADS)

Iadecola, Thomas; Neupert, Titus; Chamon, Claudio; Mudry, Christopher

2016-05-01

Coupled-wire constructions have proven to be useful tools to characterize Abelian and non-Abelian topological states of matter in two spatial dimensions. In many cases, their success has been complemented by the vast arsenal of other theoretical tools available to study such systems. In three dimensions, however, much less is known about topological phases. Since the theoretical arsenal in this case is smaller, it stands to reason that wire constructions, which are based on one-dimensional physics, could play a useful role in developing a greater microscopic understanding of three-dimensional topological phases. In this paper, we provide a comprehensive strategy, based on the geometric arrangement of commuting projectors in the toric code, to generate and characterize coupled-wire realizations of strongly interacting three-dimensional topological phases. We show how this method can be used to construct pointlike and linelike excitations, and to determine the topological degeneracy. We also point out how, with minor modifications, the machinery already developed in two dimensions can be naturally applied to study the surface states of these systems, a fact that has implications for the study of surface topological order. Finally, we show that the strategy developed for the construction of three-dimensional topological phases generalizes readily to arbitrary dimensions, vastly expanding the existing landscape of coupled-wire theories. Throughout the paper, we discuss Zm topological order in three and four dimensions as a concrete example of this approach, but the approach itself is not limited to this type of topological order.

Advanced electron microscopy methods for the analysis of MgB2 superconductor

NASA Astrophysics Data System (ADS)

Birajdar, B.; Peranio, N.; Eibl, O.

2008-02-01

Advanced electron microscopy methods used for the analysis of superconducting MgB2 wires and tapes are described. The wires and tapes were prepared by the powder in tube method using different processing technologies and thoroughly characterised for their superconducting properties within the HIPERMAG project. Microstructure analysis on μm to nm length scales is necessary to understand the superconducting properties of MgB2. For the MgB2 phase analysis on μm scale an analytical SEM, and for the analysis on nm scale a energy-filtered STEM is used. Both the microscopes were equipped with EDX detector and field emission gun. Electron microscopy and spectroscopy of MgB2 is challenging because of the boron analysis, carbon and oxygen contamination, and the presence of large number of secondary phases. Advanced electron microscopy involves, combined SEM, EPMA and TEM analysis with artefact free sample preparation, elemental mapping and chemical quantification of point spectra. Details of the acquisition conditions and achieved accuracy are presented. Ex-situ wires show oxygen-free MgB2 colonies (a colony is a dense arrangement of several MgB2 grains) embedded in a porous and oxygen-rich matrix, introducing structural granularity. In comparison, in-situ wires are generally more dense, but show inhibited MgB2 phase formation with significantly higher fraction of B-rich secondary phases. SiC additives in the in-situ wires forms Mg2Si secondary phases. The advanced electron microscopy has been used to extract the microstructure parameters like colony size, B-rich secondary phase fraction, O mole fraction and MgB2 grain size, and establish a microstructure-critical current density model [1]. In summary, conventional secondary electron imaging in SEM and diffraction contrast imaging in the TEM are by far not sufficient and advanced electron microscopy methods are essential for the analysis of superconducting MgB2 wires and tapes.

Electrochemically synthesis and optoelectronic properties of Pb- and Zn-doped nanostructured SnSe films

NASA Astrophysics Data System (ADS)

Jamali-Sheini, Farid; Cheraghizade, Mohsen; Yousefi, Ramin

2018-06-01

In this study, electrodeposition technique was applied to deposit un-, lead (Pb), and zinc (Zn)-doped SnSe films. X-ray diffraction (XRD) patterns of the films showed a polycrystalline SnSe phase with orthorhombic crystalline lattice. SEM images revealed ball-shaped, rod-shaped, and wire-shaped morphologies for SnSe films. Moreover, optical measurements indicated incorporation of dopant in the crystalline lattice of films by varying the optical energy band gap. Electrical characterization of Pb- and Zn-doped SnSe films showed their p-type nature. Finally, the solar cell device fabricated using the Zn-doped SnSe films reveal a higher efficiency because of their higher carrier concentration.

The construction technique of the high granularity and high transparency drift chamber of MEG II

NASA Astrophysics Data System (ADS)

Chiarello, G.; Chiri, C.; Corvaglia, A.; Grancagnolo, F.; Miccoli, A.; Panareo, M.; Pinto, C.; Spedicato, M.; Tassielli, G. F.

2017-07-01

The MEG experiment searches for the charged lepton flavor violating decay, μ +→ e+γ. MEG has already determined the world best upper limit on the branching ratio BR<4.2× 10-13 at 90% CL. An upgrade of the whole detector has been approved to obtain a substantial increase in sensitivity. Currently MEG is in upgrade phases, this phase involves all the detectors. The new positron tracker is a single volume, full stereo, small cells drift chamber (DCH) co-axial to the beam line. It is composed of 10 concentric layers and each single drift cell is approximately square 7 mm side, with a 20 μ m gold plated W sense wire surrounded by 40 μ m and 50 μ m silver plated Al field wires in a ratio of 5:1, about 12,000 wires. Due to the high wire density (12 wires/cm2), the use of the classical feed-through technique as wire anchoring system could hardly be implemented and therefore it was necessary to develop new wiring strategies. The number of wires and the stringent requirements on the precision of their position and on the uniformity of the wire mechanical tension impose the use of an automatic system to operate the wiring procedures. This wiring robot, designed and built at the INFN Lecce and University of Salento laboratories, consists of: ṡ a semiautomatic wiring machine with a high precision on wire mechanical tensioning (better than 0.5 g) and on wire positioning (20 μ m) for simultaneous wiring of multiwire layers; ṡ a contact-less infrared laser soldering tool; ṡ an automatic handling system for storing and transporting the multi-wire layers. The drift chamber is currently under construction at INFN and should be completed by the end of summer 2017 to be then delivered to PSI for commissioning.

Frequency response in short thermocouple wires

NASA Technical Reports Server (NTRS)

Forney, L. J.; Meeks, E. L.; Ma, J.; Fralick, G. C.

1992-01-01

Theoretical expressions are derived for the steady state frequency response of a thermocouple wire. In particular, the effects of axial heat conduction are demonstrated for a nonuniform wire with unequal material properties and wire diameters across the junction. The amplitude ratio at low frequency omega approaches 0 agrees with the results of Scadron and Warshawsky (1952) for a steady state temperature distribution. Moreover, the frequency response for a nonuniform wire in the limit of infinite length l approaches infinity is shown to reduce to a simple expression that is analogous to the classic first order solution for a thermocouple wire with uniform properties. Theoretical expressions are also derived for the steady state frequency response of a supported thermocouple wire. In particular, the effects of axial heat conduction are demonstrated for both a supported one material wire and a two material wire with unequal material properties across the junction. For the case of a one material supported wire, an exact solution is derived which compares favorably with an approximate expression that only matches temperatures at the support junction. Moreover, for the case of a two material supported wire, an analytical expression is derived that closely correlates numerical results. Experimental measurements are made for the steady state frequency response of a supported thermocouple wire. In particular, the effects of axial heat conduction are demonstrated for both a supported one material wire (type K) and a two material wire (type T) with unequal material properties across the junction. The data for the amplitude ratio and phase angle are correlated to within 10 pct. with the theoretical predictions of Forney and Fralick (1991). This is accomplished by choosing a natural frequency omega sub n for the wire data to correlate the first order response at large gas temperature frequencies. It is found that a large bead size, however, will increase the amplitude ratio at low frequencies but decrease the natural frequency of the wire. The phase angle data are also distorted for imperfect junctions.

99mTc ovalbumin labelled eggs for gastric emptying scintigraphy: in-vitro comparison of solid food markers.

PubMed

Blanc, Frédérique; Salaun, Pierre Y; Couturier, Olivier; Querellou, Solène; Le Duc-Pennec, Alexandra; Mougin-Degraef, Marie; Bizais, Yves; Legendre, Jean M

2005-11-01

The reliability of solid phase gastric emptying measurements by scintigraphy requires a marker that remains within the solid component of the test meal, and which is not degraded by the gastric juice throughout the scintigraphic procedure. In Europe, foods are most often labelled with 99mTc rhenium sulfide macrocolloid (RSMC) but this solid phase marker was withdrawn from the market in January 2004. To test other potential solid phase markers and to compare them to the reference marker RSMC. These markers were rhenium sulfide nanocolloid (RSNC), tin fluoride colloid (TFC), phytates and two albumins (Alb and AlbC). All were radiolabelled with 99mTc. After quality control, each 99mTc marker was incorporated into the albumin of one egg. Then, egg white and yolk were mixed together, and a well-cooked omelette was prepared. Aliquots of the omelette were incubated with an acidic solution of pepsin at 37 degrees C which mimicked gastric juice. Unbound radioactivity in the supernatant fraction was measured at various times up to 3 h. The radiochemical purity was > 95% for all radiopharmaceuticals. During the in-vitro incubation, the percentage of 99mTc labelled colloids released from the omelette increased continuously: after 3 h, 5% for TFC and RSMC, 8% for phytates, and > 9% for the two albumins and RSNC. Considering quality controls and release of 99mTc during in-vitro incubation of the omelette, TFC showed the same behaviour as the reference marker RSMC. Thus, TFC seems to be the best candidate to replace RSMC for the radiolabelling of the solid phase of the gastric emptying test meal.

n-Type Doping of Vapor-Liquid-Solid Grown GaAs Nanowires.

PubMed

Gutsche, Christoph; Lysov, Andrey; Regolin, Ingo; Blekker, Kai; Prost, Werner; Tegude, Franz-Josef

2011-12-01

In this letter, n-type doping of GaAs nanowires grown by metal-organic vapor phase epitaxy in the vapor-liquid-solid growth mode on (111)B GaAs substrates is reported. A low growth temperature of 400°C is adjusted in order to exclude shell growth. The impact of doping precursors on the morphology of GaAs nanowires was investigated. Tetraethyl tin as doping precursor enables heavily n-type doped GaAs nanowires in a relatively small process window while no doping effect could be found for ditertiarybutylsilane. Electrical measurements carried out on single nanowires reveal an axially non-uniform doping profile. Within a number of wires from the same run, the donor concentrations ND of GaAs nanowires are found to vary from 7 × 10(17) cm(-3) to 2 × 10(18) cm(-3). The n-type conductivity is proven by the transfer characteristics of fabricated nanowire metal-insulator-semiconductor field-effect transistor devices.

Electrochemical in situ fabrication of titanium dioxide-nanosheets on a titanium wire as a novel coating for selective solid-phase microextraction.

PubMed

Li, Yi; Zhang, Min; Yang, Yaoxia; Wang, Xuemei; Du, Xinzhen

2014-09-05

A novel TiO2-nanosheets coated fiber for solid-phase microextraction (SPME) was fabricated by anodization of Ti wire substrates in ethylene glycol with concentrated NH4F. The in situ fabricated TiO2-nanosheets were densely embedded into Ti substrates with about 1μm long, 300nm wide and 80nm thick. The as-fabricated TiO2-nanosheets coating was employed to extract polycyclic aromatic hydrocarbons, phthalates and ultraviolet (UV) filters in combination with high performance liquid chromatography-UV detection (HPLC-UV). It was found that the TiO2-nanosheets coating exhibited high extraction capability and good selectivity for some UV filters frequently used in cosmetic sunscreen formulations. The main parameters affecting extraction performance were investigated and optimized. Under the optimized conditions, the calibration graphs were linear in the range of 0.1-400μgL(-1). The limits of detection of the proposed method were between 0.026μgL(-1) and 0.089μgL(-1) (S/N=3). The single fiber repeatability varied from 4.50% to 8.76% and the fiber-to-fiber reproducibility ranged from 7.75% to 9.64% for the extraction of spiked water with 50μgL(-1) UV filters (n=5). The SPME-HPLC-UV method was successfully established for the selective preconcentration and sensitive detection of target UV filters from real environmental water samples. Recovery of UV filters spiked at 10μgL(-1) and 25μgL(-1) ranged from 88.8% to 107% and the relative standard deviations were less than 9.8%. Furthermore the in situ growth of the TiO2-nanosheets coating was performed in a highly reproducible manner and the TiO2-nanosheets coated fiber has high mechanical strength, good stability and long service life. Copyright © 2014 Elsevier B.V. All rights reserved.

Fabrication of ciprofloxacin molecular imprinted polymer coating on a stainless steel wire as a selective solid-phase microextraction fiber for sensitive determination of fluoroquinolones in biological fluids and tablet formulation using HPLC-UV detection.

PubMed

Mirzajani, Roya; Kardani, Fatemeh

2016-04-15

A molecularly imprinted polymer (MIP) fiber on stainless steel wire using ciprofloxacin template with a mild template removal condition was synthetized and evaluated for fiber solid phase microextraction (SPME) of fluoroquinolones (FQs) from biological fluids and pharmaceutical samples, followed by high performance liquid chromatography analysis with UV detection (HPLC-UV). The developed MIP fiber exhibited high selectivity for the analytes in complex matrices. The coating of the fibers were inspected using fourier transform infrared spectrophotometry, thermogaravimetric analysis, energy dispersive X-ray (EDX) spectroscopy as well as by scanning electron microscopy (SEM). The fiber shows high thermal stability (up to 300°C), good reproducibility and long lifetime. The composite coating did not swell in organic solvents nor did it strip off from the substrate. It was also highly stable and extremely adherent to the surface of the stainless steel fiber. The fabricated fiber exclusively exhibited excellent extraction efficiency and selectivity for some FQs. The effective parameters influencing the microextraction efficiency such as pH, extraction time, desorption condition, and stirring rate were investigated. Under optimized conditions, the limits of detection of the four FQs ranged from 0.023-0.033 μg L(-1) (S/N=5) and the calibration graphs were linear in the concentration range from 0.1-40 μg L(-1), the inter-day and intraday relative standard deviations (RSD) for various FQs at three different concentration level (n=5) using a single fiber were 1.1-4.4% and the fiber to fiber RSD% (n=5) was 4.3-6.7% at 5 μg L(-1) of each anlyetes. The method was successfully applied for quantification of FQs in real samples including serum, plasma and tablet formulation with the recoveries between 97 to 102%. Copyright © 2016 Elsevier B.V. All rights reserved.

Energetic electrons driven in the polarization direction of an intense laser beam incident normal to a solid target

DOE PAGES

Seely, J. F.; Hudson, L. T.; Pereira, N.; ...

2016-02-24

Experiments were performed at the LLNL Titan laser to measure the propagation direction of the energetic electrons that were generated during the interaction of the polarized laser beam with solid targets in the case of normal incidence. The energetic electrons propagated through vacuum to spectator metal wires in the polarization direction and in the perpendicular direction, and the K shell spectra from the different wire materials were recorded as functions of the distance from the laser focal spot. It was found that the fluence of the energetic electrons driven into the spectator wires in the polarization direction compared to themore » perpendicular direction was larger and increased with the distance from the focal spot. Finally, this indicates that energetic electrons are preferentially driven in the direction of the intense oscillating electric field of the incident laser beam in agreement with the multiphoton inverse Bremsstrahlung absorption process.« less

Development of subminiature multi-sensor hot-wire probes

NASA Technical Reports Server (NTRS)

Westphal, Russell V.; Ligrani, Phillip M.; Lemos, Fred R.

1988-01-01

Limitations on the spatial resolution of multisensor hot wire probes have precluded accurate measurements of Reynolds stresses very near solid surfaces in wind tunnels and in many practical aerodynamic flows. The fabrication, calibration and qualification testing of very small single horizontal and X-array hot-wire probes which are intended to be used near solid boundaries in turbulent flows where length scales are particularly small, is described. Details of the sensor fabrication procedure are reported, along with information needed to successfully operate the probes. As compared with conventional probes, manufacture of the subminiature probes is more complex, requiring special equipment and careful handling. The subminiature probes tested were more fragile and shorter lived than conventional probes; they obeyed the same calibration laws but with slightly larger experimental uncertainty. In spite of these disadvantages, measurements of mean statistical quantities and spectra demonstrate the ability of the subminiature sensors to provide the measurements in the near wall region of turbulent boundary layers that are more accurate than conventional sized probes.

Characterizing detonator output using dynamic witness plates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murphy, Michael John; Adrian, Ronald J

2009-01-01

A sub-microsecond, time-resolved micro-particle-image velocimetry (PIV) system is developed to investigate the output of explosive detonators. Detonator output is directed into a transparent solid that serves as a dynamic witness plate and instantaneous shock and material velocities are measured in a two-dimensional plane cutting through the shock wave as it propagates through the solid. For the case of unloaded initiators (e.g. exploding bridge wires, exploding foil initiators, etc.) the witness plate serves as a surrogate for the explosive material that would normally be detonated. The velocity-field measurements quantify the velocity of the shocked material and visualize the geometry of themore » shocked region. Furthermore, the time-evolution of the velocity-field can be measured at intervals as small as 10 ns using the PIV system. Current experimental results of unloaded exploding bridge wire output in polydimethylsiloxane (PDMS) witness plates demonstrate 20 MHz velocity-field sampling just 300 ns after initiation of the wire.« less

Solid state power controllers

NASA Technical Reports Server (NTRS)

Gibbs, R. S.

1974-01-01

Solid state power controllers (SSPC's) are to be considered for use as replacements of electromechanical relays and circuit breakers in future spacecraft and aircraft. They satisfy the combined function of both the relay and circuit breaker and can be remotely controlled by small signals, typically 10 mA, 5 to 28 v(dc). They have the advantage over conventional relay/circuit breaker systems in that they can be located near the utilization equipment and the primary ac or dc bus. The low level control, trip indication and status signals can be circuited by small gauge wire for control, computer interface, logic, electrical multiplexing, onboard testing, power management, and distribution purposes. This results in increased system versatility at appreciable weight saving and increased reliability. Conventional systems require the heavy gage load wiring and the control wiring to be routed from the bus to the load to other remote relay contacts, switches, sensors, etc. and to the circuit breaker located in the flight engineer's compartment for purposes of manual reset.

Development of strand burner for solid propellant burning rate studies

NASA Astrophysics Data System (ADS)

Aziz, A.; Mamat, R.; Ali, W. K. Wan

2013-12-01

It is well-known that a strand burner is an apparatus that provides burning rate measurements of a solid propellant at an elevated pressure in order to obtain the burning characteristics of a propellant. This paper describes the facilities developed by author that was used in his studies. The burning rate characteristics of solid propellant have be evaluated over five different chamber pressures ranging from 1 atm to 31 atm using a strand burner. The strand burner has a mounting stand that allows the propellant strand to be mounted vertically. The strand was ignited electrically using hot wire, and the burning time was recorded by electronic timer. Wire technique was used to measure the burning rate. Preliminary results from these techniques are presented. This study shows that the strand burner can be used on propellant strands to obtain accurate low pressure burning rate data.

Conductive-probe atomic force microscopy characterization of silicon nanowire

PubMed Central

2011-01-01

The electrical conduction properties of lateral and vertical silicon nanowires (SiNWs) were investigated using a conductive-probe atomic force microscopy (AFM). Horizontal SiNWs, which were synthesized by the in-plane solid-liquid-solid technique, are randomly deployed into an undoped hydrogenated amorphous silicon layer. Local current mapping shows that the wires have internal microstructures. The local current-voltage measurements on these horizontal wires reveal a power law behavior indicating several transport regimes based on space-charge limited conduction which can be assisted by traps in the high-bias regime (> 1 V). Vertical phosphorus-doped SiNWs were grown by chemical vapor deposition using a gold catalyst-driving vapor-liquid-solid process on higly n-type silicon substrates. The effect of phosphorus doping on the local contact resistance between the AFM tip and the SiNW was put in evidence, and the SiNWs resistivity was estimated. PMID:21711623

Quantum logic gates based on coherent electron transport in quantum wires.

PubMed

Bertoni, A; Bordone, P; Brunetti, R; Jacoboni, C; Reggiani, S

2000-06-19

It is shown that the universal set of quantum logic gates can be realized using solid-state quantum bits based on coherent electron transport in quantum wires. The elementary quantum bits are realized with a proper design of two quantum wires coupled through a potential barrier. Numerical simulations show that (a) a proper design of the coupling barrier allows one to realize any one-qbit rotation and (b) Coulomb interaction between two qbits of this kind allows the implementation of the CNOT gate. These systems are based on a mature technology and seem to be integrable with conventional electronics.

Fly-by-Wire Systems Enable Safer, More Efficient Flight

NASA Technical Reports Server (NTRS)

2012-01-01

Using the ultra-reliable Apollo Guidance Computer that enabled the Apollo Moon missions, Dryden Flight Research Center engineers, in partnership with industry leaders such as Cambridge, Massachusetts-based Draper Laboratory, demonstrated that digital computers could be used to fly aircraft. Digital fly-by-wire systems have since been incorporated into large airliners, military jets, revolutionary new aircraft, and even cars and submarines.

Manufacturing and quality control of interconnecting wire harnesses, Volume 4

NASA Technical Reports Server (NTRS)

1972-01-01

The document covers interconnecting wire harnesses defined in the design standard, including type 8, flat conductor cable. Volume breadth covers installations of groups of harnesses in a major assembly and the associated post installation inspections and electrical tests. Knowledge gained through experience on the Saturn 5 program coupled with recent advances in techniques, materials, and processes was incorporated into this document.

Solar Power Wires Based on Organic Photovoltaic Materials

NASA Astrophysics Data System (ADS)

Lee, Michael R.; Eckert, Robert D.; Forberich, Karen; Dennler, Gilles; Brabec, Christoph J.; Gaudiana, Russell A.

2009-04-01

Organic photovoltaics in a flexible wire format has potential advantages that are described in this paper. A wire format requires long-distance transport of current that can be achieved only with conventional metals, thus eliminating the use of transparent oxide semiconductors. A phase-separated, photovoltaic layer, comprising a conducting polymer and a fullerene derivative, is coated onto a thin metal wire. A second wire, coated with a silver film, serving as the counter electrode, is wrapped around the first wire. Both wires are encased in a transparent polymer cladding. Incident light is focused by the cladding onto to the photovoltaic layer even when it is completely shadowed by the counter electrode. Efficiency values of the wires range from 2.79% to 3.27%.

Processing and Characterization of Liquid-Phase Sintered NiTi Woven Structures

NASA Astrophysics Data System (ADS)

Erdeniz, Dinc; Weidinger, Ryan P.; Sharp, Keith W.; Dunand, David C.

2018-03-01

Porous NiTi is of interest for bone implants because of its unique combination of biocompatibility (encouraging osseointegration), high strength (to prevent fracture), low stiffness (to reduce stress shielding), and shape memory or superelasticity (to deploy an implant). A promising method for creating NiTi structures with regular open channels is via 3D weaving of NiTi wires. This paper presents a processing method to bond woven NiTi wire structures at contact points between wires to achieve structural integrity: (i) a slurry consisting of a blend of NiTi and Nb powders is deposited on the surface of the NiTi wires after the weaving operation; (ii) the powders are melted to create a eutectic liquid phase which collects at contact points; and (iii) the liquid is solidified and binds the NiTi woven structures. The bonded NiTi wire structures exhibited lower transformation temperatures compared to the as-woven NiTi wires because of Nb diffusion into the NiTi wires. A bonded woven sample was deformed in bending and showed near-complete recovery up to 6% strain and recovered nearly half of the deformation up to 19% strain.

Laser Indirect Shock Welding of Fine Wire to Metal Sheet.

PubMed

Wang, Xiao; Huang, Tao; Luo, Yapeng; Liu, Huixia

2017-09-12

The purpose of this paper is to present an advanced method for welding fine wire to metal sheet, namely laser indirect shock welding (LISW). This process uses silica gel as driver sheet to accelerate the metal sheet toward the wire to obtain metallurgical bonding. A series of experiments were implemented to validate the welding ability of Al sheet/Cu wire and Al sheet/Ag wire. It was found that the use of a driver sheet can maintain high surface quality of the metal sheet. With the increase of laser pulse energy, the bonding area of the sheet/wire increased and the welding interfaces were nearly flat. Energy dispersive spectroscopy (EDS) results show that the intermetallic phases were absent and a short element diffusion layer which would limit the formation of the intermetallic phases emerging at the welding interface. A tensile shear test was used to measure the mechanical strength of the welding joints. The influence of laser pulse energy on the tensile failure modes was investigated, and two failure modes, including interfacial failure and failure through the wire, were observed. The nanoindentation test results indicate that as the distance to the welding interface decreased, the microhardness increased due to the plastic deformation becoming more violent.

An isolation-enhanced quad-element antenna using suspended solid wires for LTE small-cell base stations

NASA Astrophysics Data System (ADS)

Chen, Yen-Sheng; Zhou, Huang-Cheng

2017-05-01

This paper presents a multiple-input-multiple-output (MIMO) antenna that has four-unit elements enabled by an isolation technique for long-term evolution (LTE) small-cell base stations. While earlier studies on MIMO base-station antennas cope with either a lower LTE band (698-960 MHz) or an upper LTE band (1710-2690 MHz), the proposed antenna meets the full LTE specification, yet it uses the maximum number of unit elements to increase channel capacity. The antenna configuration is optimized for good impedance matching and high radiation efficiency. In particular, as the spacing between unit elements is so small that severe mutual coupling occurs, we propose a simple structure with extremely low costs to enhance the isolation. By using suspended solid wires interconnecting the position having strong coupled current of two adjacent elements, an isolation enhancement of 37 dB is achieved. Although solid wires inherently aim at direct-current applications, this work successfully employs such a low-cost technique to microwave antenna development. Experimental results have validated the design guidelines and the proposed configuration, showing that antenna performances including impedance matching, isolation, radiation features, signal correlation, and channel capacity gain are highly desired for LTE small-cell base stations.

Texture evolution during nitinol martensite detwinning and phase transformation

NASA Astrophysics Data System (ADS)

Cai, S.; Schaffer, J. E.; Ren, Y.; Yu, C.

2013-12-01

Nitinol has been widely used to make medical devices for years due to its unique shape memory and superelastic properties. However, the texture of the nitinol wires has been largely ignored due to inherent complexity. In this study, in situ synchrotron X-ray diffraction has been carried out during uniaxial tensile testing to investigate the texture evolution of the nitinol wires during martensite detwinning, variant reorientation, and phase transformation. It was found that the thermal martensitic nitinol wire comprised primarily an axial (1¯20), (120), and (102)-fiber texture. Detwinning initially converted the (120) and (102) fibers to the (1¯20) fiber and progressed to a (1¯30)-fiber texture by rigid body rotation. At strains above 10%, the (1¯30)-fiber was shifted to the (110) fiber by (21¯0) deformation twinning. The austenitic wire exhibited an axial (334)-fiber, which transformed to the near-(1¯30) martensite texture after the stress-induced phase transformation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takai, Yoshizo; Kawasaki, Tadahiro; Kimura, Yoshihide

A single-atom-sized gold wire was successfully observed in real time by a newly developed defocus-image modulation processing electron microscope. Because of phase retrieval processing with spherical aberration correction, the single-atom strand wire was observed with high contrast and without contrast blurring. By carefully looking at the atomic distance, the contrast, and the dynamic behavior of the wire, we recognized that there are two stages of the wire. In the first stage the wire maintained the atomic distance in the bulk crystal, but in the second stage the wire showed the atomic distance of the nearest-neighbor atoms with weaker contrast. Themore » gold wire was rather stable for a few seconds under strong electron beam illumination.« less

Heat Transfer Measurements during DC Casting of Aluminium Part I: Measurement Technique

NASA Astrophysics Data System (ADS)

Bakken, J. A.; Bergström, T.

A method for determination of surface heat transfer to the cooling water and mould based on in-situ temperature measurements in the DC cast ingot has been developed. Three or more steel mantled coaxial thermocouples (0.5 mm diam.) are mounted on a wire frame called a "harp". Allowing the "harp" to freeze into the solid ingots during the casting time-temperature plots T1 (t), T2(t), T3 (t) are obtained for three moving points positioned typically 3, 7 and 11 mm from the ingot surface. From these measurements surface temperature, heat flux and heat transfer coefficients are computed as functions of vertical distance. The computer program is based on steady-state two-dimensional heat balances with convective terms for two fixed volume elements: one around thermocouple T1 and one surface element. A special numerical smoothing procedure is incorporated. The heat of solidification is taken into account.

Bioavailable cadmium during the bioremediation of phenanthrene-contaminated soils using the diffusive gradients in thin-film technique.

PubMed

Amezcua-Allieri, M A; Rodríguez-Vázquez, R

2006-03-01

To study the impact of fungal bioremediation of phenanthrene on trace cadmium solid-solution fluxes and solution phase concentration. The bioremediation of phenanthrene in soils was performed using the fungus Penicillium frequentans. Metal behaviour was evaluated by the techniques of diffusive gradient in thin-films (DGT) and filtration. Fluxes of cadmium (Cd) show a significant (P < 0.002) increase after the start of bioremediation, indicating that the bioremediation process itself releases significant amount of Cd into solution from the soil solid-phase. Unlike DGT devices, the solution concentration from filtration shows a clear bimodal distribution. We postulate that the initial action of the fungi is most likely to breakdown the surface of the solid phase to smaller, 'solution-phase' material (<0.45 microm) leading to a peak in Cd concentration in solution. Phenanthrene removal from soils by bioremediation ironically results in the mobilization of another toxic pollutant (Cd). Bioremediation of organic pollutants in contaminated soil will likely lead to large increases in the mobilization of toxic metals, increasing metal bio-uptake and incorporation into the wider food chain. Bioremediation strategies need to account for this behaviour and further research is required both to understand the generality of this behaviour and the operative mechanisms.

76 FR 63304 - Guidance for Industry on Incorporation of Physical-Chemical Identifiers Into Solid Oral Dosage...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-12

...] Guidance for Industry on Incorporation of Physical-Chemical Identifiers Into Solid Oral Dosage Form Drug... entitled ``Incorporation of Physical-Chemical Identifiers Into Solid Oral Dosage Form Drug Products for Anticounterfeiting.'' This guidance provides recommendations on design considerations for incorporating physical...

Control of ice chromatographic retention mechanism by changing temperature and dopant concentration.

PubMed

Tasaki, Yuiko; Okada, Tetsuo

2011-12-15

A liquid phase coexists with solid water ice in a typical binary system, such as NaCl-water, in the temperature range between the freezing point and the eutectic point (t(eu)) of the system. In ice chromatography with salt-doped ice as the stationary phase, both solid and liquid phase can contribute to solute retention in different fashions; that is, the solid ice surface acts as an adsorbent, while a solute can be partitioned into the liquid phase. Thus, both adsorption and partition mechanisms can be utilized for ice chromatographic separation. An important feature in this approach is that the liquid phase volume can be varied by changing the temperature and the concentration of a salt incorporated into the ice stationary phase. Thus, we can control the relative contribution from the partition mechanism in the entire retention because the liquid phase volume can be estimated from the freezing depression curve. Separation selectivity can thereby be modified. The applicability of this concept has been confirmed for the solutes of different adsorption and partition abilities. The predicted retention based on thermodynamics basically agrees well with the corresponding experimental retention. However, one important inconsistency has been found. The calculation predicts a step-like discontinuity of the solute retention at t(eu) because the phase diagram suggests that the liquid phase abruptly appears at t(eu) when the temperature increases. In contrast, the corresponding experimental plots are continuous over the wider range including the subeutectic temperatures. This discrepancy is explained by the existence of the liquid phase below t(eu). A difference between predicted and measured retention factors allows the estimation of the volume of the subeutectic liquid phase.

Incorporation of a Bio-Active Reverse-Turn Heterocycle into a Peptide Template Using Solid-Phase Synthesis to Probe Melanocortin Receptor Selectivity and Ligand Conformations by 2D 1H NMR

PubMed Central

Singh, Anamika; Wilczynski, Andrzej; Holder, Jerry R.; Witek, Rachel M.; Dirain, Marvin L.; Xiang, Zhimin; Edison, Arthur S.; Haskell-Luevano, Carrie

2011-01-01

Using a solid-phase synthetic approach, a bioactive reverse turn heterocyclic was incorporated into a cyclic peptide template to probe melanocortin receptor potency and ligand structural conformations. The five melanocortin receptor isoforms (MC1R-MC5R) are G-protein coupled receptors (GPCRs) that are regulated by endogenous agonists and antagonists. This pathway is involved in pigmentation, weight, and energy homeostasis. Herein, we report novel analogues of the chimeric AGRP-melanocortin peptide template integrated with a small molecule moiety to probe the structural and functional consequences of the core His-Phe-Arg-Trp peptide domain using a reverse-turn heterocycle. A series of six compounds are reported that result in inactive to full agonists with nM potency. Biophysical structural analysis [2D 1H NMR and computer-assisted molecular modeling (CAMM)] were performed on selected analogues, resulting in the identification that these peptide-small molecule hybrids possessed increased flexibility and fewer discrete conformational families as compared to the reference peptide and result in a novel template for further structure-function studies. PMID:21306168

Frequency response of a thermocouple wire: Effects of axial conduction

NASA Technical Reports Server (NTRS)

Forney, L. J.; Fralick, G. C.

1990-01-01

Theoretical expressions are derived for the steady-state frequency response of a thermocouple wire. In particular, the effects of axial heat conduction are demonstrated for both a uniform thermocouple wire and a nonuniform wire with unequal material properties and wire diameters across the junction. For the case of a uniform wire, the amplitude ratio and phase angle compare favorably with the series solution of Scadron and Warshawsky (1952) except near the ends of the wire. For the case of a non-uniform wire, the amplitude ratio at low frequency omega yields 0 agrees with the results of Scadron and Warshawsky for a steady-state temperature distribution. Moreover, the frequency response for a non-uniform wire in the limit of infinite length l yields infinity is shown to reduce to a simple expression that is analogous to the classic first order solution for a thermocouple wire with uniform properties.

An oscillating microbalance for meteorological measurements of ice and volcanic ash accumulation from a weather balloon platform

NASA Astrophysics Data System (ADS)

Airey, Martin; Harrison, Giles; Nicoll, Keri; Williams, Paul; Marlton, Graeme

2017-04-01

A new, low cost, instrument has been developed for meteorological measurements of the accumulation of ice and volcanic ash that can be readily deployed using commercial radiosondes and weather balloons. It is based on principles used by [1], an instrument originally developed to measure supercooled liquid water profiles in clouds. This new instrument introduces numerous improvements in terms of reduced complexity and cost. It uses the oscillating microbalance principle, whereby a wire vibrating at its natural frequency is subjected to increased loading of the property to be measured. The increase in mass modifies the wire properties such that its natural frequency of oscillation changes. By measuring this frequency, the increase in mass can be inferred and transmitted to a ground base station through the radiosonde's UHF antenna via the PANDORA interface [2], which has been previously developed to provide power and connection to the radiosonde telemetry. The device consists of a simple circuit board controlled by an ATMEGA microcontroller. For calibration, the controller is capable of driving the wire at specified frequencies via excitation by a piezo sounder upon which the wire is mounted. The same piezo sounder is also used during active operation to measure the frequency of the wire in its non-driven state in order to infer the mass change on the wire. A phase-locked loop implemented on the board identifies when resonance occurs and the measured frequency is stable, prompting the microcontroller to send the measurement through the data interface. The device may be used for any application that requires the measurement of incremental mass variation e.g. ice accumulation, frosting, or particle accumulation such as dust and volcanic ash. For the solid particle accumulation, a low temperature, high-tack, adhesive may be applied to the wire prior to deployment to collect the material. In addition, the same instrument may be used for ground-based applications, such as ice accumulation, with direct monitoring via a serial connection or logged to removable storage media in the absence of the radiosonde. References [1] Hill, G.E. and Woffinden, D.S. (1980) Journal of Applied Meteorology, 19, 11, 1285-1292 [2] Harrison, R.G., et al. (2012) Rev. Sci. Instrum., 83, 3

Self-assembly of tin wires via phase transformation of heteroepitaxial germanium-tin on germanium substrate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Wei; Li, Lingzi; Yeo, Yee-Chia, E-mail: yeo@ieee.org

This work demonstrates and describes for the first time an unusual strain-relaxation mechanism by the formation and self-assembly of well-ordered tin wires during the thermal annealing of epitaxial Ge{sub 0.83}Sn{sub 0.17}-on-Ge(001) substrate. Fully strained germanium-tin alloys (Ge{sub 0.83}Sn{sub 0.17}) were epitaxially grown on Ge(001) substrate by molecular beam epitaxy. The morphological and compositional evolution of Ge{sub 0.83}Sn{sub 0.17} during thermal annealing is studied by atomic force microscopy, X-ray diffraction, transmission electron microscopy. Under certain annealing conditions, the Ge{sub 0.83}Sn{sub 0.17} layer decomposes into two stable phases, and well-defined Sn wires that are preferentially oriented along two orthogonal 〈100〉 azimuths aremore » formed. The formation of the Sn wires is related to the annealing temperature and the Ge{sub 0.83}Sn{sub 0.17} thickness, and can be explained by the nucleation of a grain with Sn islands on the outer front, followed by grain boundary migration. The Sn wire formation process is found to be thermally activated, and an activation enthalpy (E{sub c}) of 0.41 eV is extracted. This thermally activated phase transformation, i.e., 2D epitaxial layer to 3D wires, occurs via a mechanism akin to “cellular precipitation.” This synthesis route of Sn wires opens new possibilities for creation of nanoscale patterns at high-throughput without the need for lithography.« less

Hollow mesoporous carbon spheres-based fiber coating for solid-phase microextraction of polycyclic aromatic hydrocarbons.

PubMed

Hu, Xingru; Liu, Chao; Li, Jiansheng; Luo, Rui; Jiang, Hui; Sun, Xiuyun; Shen, Jinyou; Han, Weiqing; Wang, Lianjun

2017-10-20

In this study, a novel hollow mesoporous carbon spheres-based fiber (HMCSs-F) was fabricated to immobilize HMCSs onto a stainless steel wire for solid-phase microextraction (SPME). Characterization results showed that the HMCSs-F possessed a large specific surface area, high porosity and uniform pore size. To demonstrate the extraction performance, a series of polycyclic aromatic hydrocarbons (PAHs) was chosen as target analytes. The experimental parameters including extraction and desorption conditions were optimized. Compared to commercial fibers, the HMCSs-F exhibited better extraction efficiency for PAHs. More interestingly, a good extraction selectivity for PAHs from the complex matrix was observed in these HMCSs-F. The enhanced SPME performance was attributed to the unique pore structure and special surface properties of the HMCSs. Furthermore, under the optimum conditions, the limits of detection (LODs) for the HMCSs-F were in the range of 0.20-1.15ngL -1 with a corresponding relative standard deviation that was below 8.6%. The method was successfully applied for the analysis of PAHs in actual environmental water samples with recoveries ranging from 85.9% to 112.2%. These results imply that the novel HMCSs-F have potential application in environmental water analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

Tensile Strength and Hardness Correlations with Microscopy in Friction welded Aluminium to Copper

NASA Astrophysics Data System (ADS)

Satish, Rengarajan; Seshagiri Rao, Vaddi; Ananthapadmanaban, Dattaguru; Ravi, Balappa

2016-01-01

Aluminium and copper are good conductors of heat and electricity, copper being the better conductor, is a costly metal indeed. On the other hand, aluminium is cheap, easily available and also has a lower density than copper. Hence, worldwide efforts are being made to partially replace copper wire. Solid state welding should be used to join aluminium to copper. This is because the use of fusion welding results in brittle phases formed in the weld interface. One of the solid state welding techniques used for joining aluminium to copper is friction welding. In this paper, an attempt has been made to join aluminium to copper by friction welding by varying the friction welding parameters, namely friction pressure, upset pressure, burn-off length and speed of rotation of the workpiece. Nine different friction welding parameter combinations were used during welding in accordance with ASTM standards and results have been reported. Tensile strength and hardness tests were carried out for each parameter combination. Optimum friction welding parameter combination was identified with respect to tensile strength. Scanning Electron Microscopy and Electron dispersive spectroanalysis were obtained to identify modes of fracture and presence of intermetallic phases for each friction welding combination with the aim to narrow down friction welding parameters that give good properties on the whole.

Polydimethylsiloxane/metal-organic frameworks coated fiber for solid-phase microextraction of polycyclic aromatic hydrocarbons in river and lake water samples.

PubMed

Zhang, Guijiang; Zang, Xiaohuan; Li, Zhi; Wang, Chun; Wang, Zhi

2014-11-01

In this study, polydimethylsiloxane/metal-organic frameworks (PDMS/MOFs), including PDMS/MIL-101 and PDMS/MOF-199, were immobilized onto a stainless steel wire through sol-gel technique as solid-phase microextraction (SPME) fiber coating. The prepared fibers were used for the extraction of some polycyclic aromatic hydrocarbons (PAHs) from water samples prior to gas chromatography-mass spectrometry (GC-MS) analysis. Under the optimized experiment conditions, the PDMS/MIL-101 coated fiber exhibited higher extraction efficiency towards PAHs than that of PDMS/MOF-199. Several parameters affecting the extraction of PAHs by SPME with PDMS/MIL-101 fiber, including the extraction temperature, extraction time, sample volume, salt addition and desorption conditions, were investigated. The limits of detection (LODs) were less than 4.0 ng L(-1) and the linearity was observed in the range from 0.01 to 2.0 µg L(-1) with the correlation coefficients (r) ranging from 0.9940 to 0.9986. The recoveries of the method for the PAHs from water samples at spiking levels of 0.05 and 0.2 µg L(-1) ranged from 78.2% to 110.3%. Single fiber repeatability and fiber-to-fiber reproducibility were less than 9.3% and 13.8%, respectively. Copyright © 2014 Elsevier B.V. All rights reserved.

Upward shift of the vortex solid phase in high-temperature-superconducting wires through high density nanoparticle addition

DOE PAGES

Miura, Masashi; Maiorov, Boris; Balakirev, Fedor F.; ...

2016-02-08

Here, we show a simple and effective way to improve the vortex irreversibility line up to very high magnetic fields (60T) by increasing the density of second phase BaZrO 3 nanoparticles. (Y 0.77,Gd 0.23)Ba 2Cu 3O y films were grown on metal substrates with different concentration of BaZrO 3 nanoparticles by the metal organic deposition method. We find that upon increase of the BaZrO 3 concentration, the nanoparticle size remains constant but the twin-boundary density increases. Up to the highest nanoparticle concentration (n ~ 1.3 × 10 22/m 3), the irreversibility field (H irr) continues to increase with no signmore » of saturation up to 60 T, although the vortices vastly outnumber pinning centers. We find extremely high H irr, namely H irr = 30 T (H||45°) and 24 T (H||c) at 65 K and 58 T (H||45°) and 45 T (H||c) at 50K. The difference in pinning landscape shifts the vortex solid-liquid transition upwards, increasing the vortex region useful for power applications, while keeping the upper critical field, critical temperature and electronic mass anisotropy unchanged.« less

Graphene oxide based sol-gel stainless steel fiber for the headspace solid-phase microextraction of organophosphate ester flame retardants in water samples.

PubMed

Jin, Tingting; Cheng, Jing; Cai, Cuicui; Cheng, Min; Wu, Shiju; Zhou, Hongbin

2016-07-29

In this paper, graphene oxide was coated onto a stainless steel wire through sol-gel technique and it was used as a solid phase microextraction (SPME) fiber. The prepared fiber was characterized by scanning electron microscopy (SEM), which displayed that the fiber had crinkled surface and porous structure The application of the fiber was evaluated through the headspace SPME of nine organophosphate ester flame retardants (OPFRs) with different characteristics in water samples followed by gas chromatography and nitrogen-phosphorous detector (GC/NPD). The major factors influencing the extraction efficiency, including the extraction and desorption conditions, were studied and optimized. Under the optimum conditions, the proposed method was evaluated, and applied to the analysis of organophosphate ester flame retardants in real environmental water samples. The results demonstrated the HS-SPME method based on GO sol-gel fiber had good linearity (R>0.9928), and limits of detection (1.4-135.6ngL(-1)), high repeatability (RSD<9.8%) and good recovery (76.4-112.4%). The GO based sol-gel fiber displayed bigger extraction capability than the commercial PDMS fiber and the pure sol-gel fiber for both polar and apolar organophosphate esters, especially for the OPFRs containing benzene rings. Copyright © 2016 Elsevier B.V. All rights reserved.

Novel double-confined polymeric ionic liquids as sorbents for solid-phase microextraction with enhanced stability and durability in high-ionic-strength solution.

PubMed

Feng, Juanjuan; Sun, Min; Xu, Lili; Wang, Shuai; Liu, Xia; Jiang, Shengxiang

2012-12-14

Because of the occurrence of ion exchange between high-ionic-strength solution and anions of polymeric ionic liquids (PILs), PILs based solid-phase microextraction (SPME) fibers were rarely used in direct immersion mode to high-salt-added samples. In this work, a novel double-confined PIL sorbent was prepared by co-polymerization of cation and anion of 1-vinyl-3-octylimidzaolium p-styrenesulfonate (VOIm(+)SS(-)). The poly(VOIm(+)-SS(-)) was chemically bonded onto functionalized stainless steel wire via surface radical chain-transfer reaction. Stability of poly(VOIm(+)-SS(-)) in high-ionic-strength solution was investigated and compared with that of poly(1-vinyl-3-octylimidzaolium benzenesulfonate) (poly(VOIm(+)BS(-))) by elemental analysis of sulfur element, and results turned out that the poly(VOIm(+)-SS(-)) was more stable. Coupled to gas chromatography (GC), the poly(VOIm(+)-SS(-)) fiber was used to extract three sorts of compounds including anilines, phenols and phthalate esters in aqueous solution. The as-established method showed good linearity, low detection limits, and acceptable repeatability. The direct immersion SPME-GC method was applied to determine the model phthalate esters in bottled mineral water. The determination results were satisfactory. Copyright © 2012 Elsevier B.V. All rights reserved.

End-Member Formulation of Solid Solutions and Reactive Transport

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lichtner, Peter C.

2015-09-01

A model for incorporating solid solutions into reactive transport equations is presented based on an end-member representation. Reactive transport equations are solved directly for the composition and bulk concentration of the solid solution. Reactions of a solid solution with an aqueous solution are formulated in terms of an overall stoichiometric reaction corresponding to a time-varying composition and exchange reactions, equivalent to reaction end-members. Reaction rates are treated kinetically using a transition state rate law for the overall reaction and a pseudo-kinetic rate law for exchange reactions. The composition of the solid solution at the onset of precipitation is assumed tomore » correspond to the least soluble composition, equivalent to the composition at equilibrium. The stoichiometric saturation determines if the solid solution is super-saturated with respect to the aqueous solution. The method is implemented for a simple prototype batch reactor using Mathematica for a binary solid solution. Finally, the sensitivity of the results on the kinetic rate constant for a binary solid solution is investigated for reaction of an initially stoichiometric solid phase with an undersaturated aqueous solution.« less

Improved Solver Settings for 3D Exploding Wire Simulations in ALEGRA

DTIC Science & Technology

2016-08-01

expanding plasma and shock wave resulting from the wire burst can extend to tens of cen- timeters. The elliptic nature of the magnetic diffusion...such simulations were prohibitively slow due in part to unoptimized (matrix) solver settings. In this report, we address that by varying 6 parameters...distribution is unlimited. simulation code developed by SNL for modeling high-deformation solid dynam- ics, shock -hydrodynamics, magnetohydrodynamics

48 CFR 225.7003-3 - Exceptions.

Code of Federal Regulations, 2014 CFR

2014-10-01

..., slab, wire, plate, and sheet, that have not been incorporated into end items, subsystems, assemblies... are incorporated into COTS end items, subsystems, or assemblies; (C) Commercially available high... COTS end items or subsystems (see PGI 225.7003-3(b)(6) for a table of applicability of specialty metals...

Conformal bi-layered perovskite/spinel coating on a metallic wire network for solid oxide fuel cells via an electrodeposition-based route

NASA Astrophysics Data System (ADS)

Park, Beom-Kyeong; Song, Rak-Hyun; Lee, Seung-Bok; Lim, Tak-Hyoung; Park, Seok-Joo; Jung, WooChul; Lee, Jong-Won

2017-04-01

Solid oxide fuel cells (SOFCs) require low-cost metallic components for current collection from electrodes as well as electrical connection between unit cells; however, the degradation of their electrical properties and surface stability associated with high-temperature oxidation is of great concern. It is thus important to develop protective conducting oxide coatings capable of mitigating the degradation of metallic components under SOFC operating conditions. Here, we report a conformal bi-layered coating composed of perovskite and spinel oxides on a metallic wire network fabricated by a facile electrodeposition-based route. A highly dense, crack-free, and adhesive bi-layered LaMnO3/Co3O4 coating of ∼1.2 μm thickness is conformally formed on the surfaces of wires with ∼100 μm diameter. We demonstrate that the bi-layered LaMnO3/Co3O4 coating plays a key role in improving the power density and durability of a tubular SOFC by stabilizing the surface of the metallic wire network used as a cathode current collector. The electrodeposition-based technique presented in this study offers a low-cost and scalable process to fabricate conformal multi-layered coatings on various metallic structures.

The influence of Ni(II) on brushite structure stabilization

NASA Astrophysics Data System (ADS)

Guerra-López, J. R.; Güida, J. A.; Ramos, M. A.; Punte, G.

2017-06-01

Brushite samples doped with Ni(II) in different concentrations, from 5% to 20%, were prepared in aqueous solution at pH = 7 and at two temperatures: 25 and 37 °C. The solid samples were characterized by chemical analysis, infrared spectroscopy (FTIR) and x-ray powder diffraction (XRPD). Chemical analysis has shown Ni(II) almost complete incorporation to the solid phase up to 15%. X-ray diffraction patterns have allowed to identify brushite phase with almost no modification of the line breadth and only small shifts of lines positions with increasing Ni(II) incorporation up to 15%. For larger Ni(II) concentration, in solution, a mixture of phases has been detected. Infrared spectra have supported diffraction results. For Ni(II) 20% and over the characteristic bands of HPO42- anions tend to vanish, and the typical shaped PO43- bands are observed. These results have allowed to establish that the presence of low levels of Ni in the synthetic process not only helps brushite formation; but, also prevents brushite from apatite conversion and, in addition, preserves brushite crystallinity. According to these findings, it is possible to propose that nickel traces present in the urinary system might be a trigger to brushite stone formation and/or growth, rather than the expected brushite conversion to hydroxyapatite. This outcome would explain the recurrent detection of difficult to treat brushite stones, observed in the last three decades.

Multi-thread parallel algorithm for reconstructing 3D large-scale porous structures

NASA Astrophysics Data System (ADS)

Ju, Yang; Huang, Yaohui; Zheng, Jiangtao; Qian, Xu; Xie, Heping; Zhao, Xi

2017-04-01

Geomaterials inherently contain many discontinuous, multi-scale, geometrically irregular pores, forming a complex porous structure that governs their mechanical and transport properties. The development of an efficient reconstruction method for representing porous structures can significantly contribute toward providing a better understanding of the governing effects of porous structures on the properties of porous materials. In order to improve the efficiency of reconstructing large-scale porous structures, a multi-thread parallel scheme was incorporated into the simulated annealing reconstruction method. In the method, four correlation functions, which include the two-point probability function, the linear-path functions for the pore phase and the solid phase, and the fractal system function for the solid phase, were employed for better reproduction of the complex well-connected porous structures. In addition, a random sphere packing method and a self-developed pre-conditioning method were incorporated to cast the initial reconstructed model and select independent interchanging pairs for parallel multi-thread calculation, respectively. The accuracy of the proposed algorithm was evaluated by examining the similarity between the reconstructed structure and a prototype in terms of their geometrical, topological, and mechanical properties. Comparisons of the reconstruction efficiency of porous models with various scales indicated that the parallel multi-thread scheme significantly shortened the execution time for reconstruction of a large-scale well-connected porous model compared to a sequential single-thread procedure.

Microstructures and Mechanical Properties of as-Drawn and Laboratory Annealed Pearlitic Steel Wires

NASA Astrophysics Data System (ADS)

Durgaprasad, A.; Giri, S.; Lenka, S.; Kundu, S.; Mishra, S.; Chandra, S.; Doherty, R. D.; Samajdar, I.

2017-10-01

Near eutectoid fully pearlitic wire rod (5.5 mm diameter) was taken through six stages of wire drawing (drawing strains of 0 to 2.47). The as-drawn (AD) wires were further laboratory annealed (LA) to re-austenitize and reform the pearlite. AD and LA grades, for respective wire diameters, had similar pearlite microstructure: interlamellar spacing ( λ) and pearlite alignment with the wire axis. However, LA grade had lower hardness (for both phases) and slightly lower fiber texture and residual stresses in ferrite. Surprisingly, essentially identical tensile yield strengths in AD and LA wires, measured at equivalent spacing, were found. The work hardened AD had, as expected, higher torsional yield strengths and lower tensile and torsional ductilities than LA. In both wires, stronger pearlite alignment gave significantly increased torsional ductility.

Nucleic acid extraction techniques and application to the microchip.

PubMed

Price, Carol W; Leslie, Daniel C; Landers, James P

2009-09-07

As recently as the early 1990s, DNA purification was time-consuming, requiring the use of toxic, hazardous reagents. The advent of solid phase extraction techniques and the availability of commercial kits for quick and reliable DNA extraction has relegated those early techniques largely to the history books. High quality DNA can now be extracted from whole blood, serum, saliva, urine, stool, cerebral spinal fluid, tissues, and cells in less time without sacrificing recovery. Having achieved such a radical change in the methodology of DNA extraction, focus has shifted to adapting these methods to a miniaturized system, or "lab-on-a-chip" (A. Manz, N. Graber and H. M. Widmer, Sens. Actuators, B, 1990, 1, 244-248). Manz et al.'s concept of a "miniaturized total chemical analysis system" (microTAS) involved a silicon chip that incorporated sample pretreatment, separation and detection. This review will focus on the first of these steps, sample pretreatment in the form of DNA purification. The intention of this review is to provide an overview of the fundamentals of nucleic acid purification and solid phase extraction (SPE) and to discuss specific microchip DNA extraction successes and challenges. In order to fully appreciate the advances in DNA purification, a brief review of the history of DNA extraction is provided so that the reader has an understanding of the impact that the development of SPE techniques have had. This review will highlight the different methods of nucleic acid extraction (Table 1), including relevant citations, but without an exhaustive summary of the literature. A recent review by Wen et al. (J. Wen, L. A. Legendre, J. M. Bienvenue and J. P. Landers, Anal. Chem., 2008, 80, 6472-6479) covers solid phase extraction methods with a greater focus on their incorporation into integrated microfluidic systems.

Measurements of cross-sectional instantaneous phase distribution in gas-liquid pipe flow

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roitberg, E.; Shemer, L.; Barnea, D.

Two novel complementing methods that enable experimental study of gas and liquid phases distribution in two-phase pipe flow are considered. The first measuring technique uses a wire-mesh sensor that, in addition to providing data on instantaneous phase distribution in the pipe cross-section, also allows measuring instantaneous propagation velocities of the phase interface. A novel algorithm for processing the wire-mesh sensor data is suggested to determine the instantaneous boundaries of gas-liquid interface. The second method applied here takes advantage of the existence of sharp visible boundaries between the two phases. This optical instrument is based on a borescope that is connectedmore » to a digital video camera. Laser light sheet illumination makes it possible to obtain images in the illuminated pipe cross-section only. It is demonstrated that the wire-mesh-derived results based on application of the new algorithm improve the effective spatial resolution of the instrument and are in agreement with those obtained using the borescope. Advantages and limitations of both measuring techniques for the investigations of cross-sectional instantaneous phase distribution in two-phase pipe flows are discussed. (author)« less

Engineered pinning landscapes for enhanced 2G coil wire

DOE PAGES

Rupich, Martin W.; Sathyamurthy, Srivatsan; Fleshler, Steven; ...

2016-04-01

We demonstrate a twofold increase in the in-field critical current of AMSC's standard 2G coil wire by irradiation with 18-MeV Au ions. The optimum pinning enhancement is achieved with a dose of 6 × 10 11 Au ions/cm 2. Although the 77 K, self-field critical current is reduced by about 35%, the in-field critical current (H//c) shows a significant enhancement between 4 and 50 K in fields > 1 T. The process was used for the roll-to-roll irradiation of AMSC's standard 46-mm-wide production coated conductor strips, which were further processed into standard copper laminated coil wire. The long-length wires showmore » the same enhancement as attained with short static irradiated samples. The roll-to-roll irradiation process can be incorporated in the standard 2G wire manufacturing, with no modifications to the current process. In conclusion, the enhanced performance of the wire will benefit rotating machine and magnet applications.« less

Network Management and FDIR for SpaceWire Networks (N-MaSS)

NASA Astrophysics Data System (ADS)

Montano, Giuseppe; Jameux, David; Cook, Barry; Peel, Rodger; McCormick, Ecaterina; Walker, Paul; Kollias, Vangelis; Pogkas, Nikos

2014-08-01

The SpaceWire network management layer, which manages network topology and routing, is not yet standardised. This paper presents the European Space Agency (ESA) N-MaSS study, which focuses on implementation and standardisation of Fault Detection, Isolation and Recovery (FDIR) functions within the SpaceWire network management layer. N-MaSS provides an autonomous FDIR solution. It is defined at the SpaceWire network layer in order to achieve efficient re-use for heterogeneous missions, allowing for the incorporation of legacy equipment. The N-MaSS FDIR functions identify SpaceWire link and node failures and provide recovery using redundant nodes.This paper provides an overview of the overall N- MaSS study. In particular, the following topics are discussed: (a) how user requirements have been captured from the industry, SpaceWire Working Group and ESA; (b) how the N-MaSS architecture was organically shaped on the basis of the requirements captured; (c) how the N-MaSS concept is currently being implemented in a demonstrator and verified.

Equations of state for hydrogen and deuterium.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kerley, Gerald Irwin

2003-12-01

This report describes the complete revision of a deuterium equation of state (EOS) model published in 1972. It uses the same general approach as the 1972 EOS, i.e., the so-called 'chemical model,' but incorporates a number of theoretical advances that have taken place during the past thirty years. Three phases are included: a molecular solid, an atomic solid, and a fluid phase consisting of both molecular and atomic species. Ionization and the insulator-metal transition are also included. The most important improvements are in the liquid perturbation theory, the treatment of molecular vibrations and rotations, and the ionization equilibrium and mixturemore » models. In addition, new experimental data and theoretical calculations are used to calibrate certain model parameters, notably the zero-Kelvin isotherms for the molecular and atomic solids, and the quantum corrections to the liquid phase. The report gives a general overview of the model, followed by detailed discussions of the most important theoretical issues and extensive comparisons with the many experimental data that have been obtained during the last thirty years. Questions about the validity of the chemical model are also considered. Implications for modeling the 'giant planets' are also discussed.« less

Fabrication of MgB2 monofilament wire by in-situ using powder-in-tube (PIT) method

NASA Astrophysics Data System (ADS)

Rasyadi, Muhammad Emir Hanif; Yudanto, Sigit Dwi; Imaduddin, Agung; Sawitri, Dyah

2018-04-01

In this research we have studied the making of MgB2 superconducting monofilament wire using powder-in-tube method with variation of Mg composition to B ie 0.90, 1.00 and 1.10, while Boron remains The precursor used is Mg powder (98%) and powder B (95%) Both materials are mixed and then crushed with agate mortar for 30 minutes and then put into stainless steel tube 316. The tube is then subjected to a mechanical treatment of rolling to form its monofilament wire. The wire is then cut and sintered at a temperature of 800o C for 2 hours. After that we measure the critical temperature then characterize the samples by XRD and SEM. From the result of this research it was found that in-situ wire-making by powder-in-tube method can make MgB2 superconducting monofilament wire with MgB2 as the dominant phase around 95% and MgO as the impurity phase around 5%. MgO is formed due to the oxidation occurring in the MgB2 powder inside the wire. The optimal Mg:B composition to make this wire is in the 1:2 composition Because it has a good resistivity curve with a high enough Tc Onset that is 41,67 K and Tc Zero 40,89 K. However, there is a porosity in the wire due to the volume reduction of the Mg + 2B reaction plus the evaporation of Mg.

Microstructural studies of 35 degrees C copper Ni-Ti orthodontic wire and TEM confirmation of low-temperature martensite transformation.

PubMed

Brantley, William A; Guo, Wenhua; Clark, William A T; Iijima, Masahiro

2008-02-01

Previous temperature-modulated differential scanning calorimetry (TMDSC) study of nickel-titanium orthodontic wires revealed a large exothermic low-temperature peak that was attributed to transformation within martensitic NiTi. The purpose of this study was to use transmission electron microscopy (TEM) to verify this phase transformation in a clinically popular nickel-titanium wire, identify its mechanism and confirm other phase transformations found by TMDSC, and to provide detailed information about the microstructure of this wire. The 35 degrees C Copper nickel-titanium wire (Ormco) with cross-section dimensions of 0.016 in. x 0.022 in. used in the earlier TMDSC investigation was selected. Foils were prepared for TEM analyses by mechanical grinding, polishing, dimpling, ion milling and plasma cleaning. Standard bright-field and dark-field TEM images were obtained, along with convergent-beam electron diffraction patterns. A cryo-stage with the electron microscope (Phillips CM 200) permitted the specimen to be observed at -187, -45, and 50 degrees C, as well as at room temperature. Microstructures were also observed with an optical microscope and a scanning electron microscope. Room temperature microstructures had randomly oriented, elongated grains that were twinned. Electron diffraction patterns confirmed that phase transformations took place over temperature ranges previously found by TMDSC. TEM observations revealed a high dislocation density and fine-scale oxide particles, and that twinning is the mechanism for the low-temperature transformation in martensitic NiTi. TEM confirmed the low-temperature peak and other phase transformations observed by TMDSC, and revealed that twinning in martensite is the mechanism for the low-temperature peak. The high dislocation density and fine-scale oxide particles in the microstructure are the result of the wire manufacturing process.

An interactive modeling program for the generation of planar polygons for boundary type solids representations of wire frame models

NASA Technical Reports Server (NTRS)

Ozsoy, T.; Ochs, J. B.

1984-01-01

The development of a general link between three dimensional wire frame models and rigid solid models is discussed. An interactive computer graphics program was developed to serve as a front end to an algorithm (COSMIC Program No. ARC-11446) which offers a general solution to the hidden line problem where the input data is either line segments of n-sided planar polygons of the most general type with internal boundaries. The program provides a general interface to CAD/CAM data bases and is implemented for models created on the Unigraphics VAX 11/780-based CAD/CAM systems with the display software written for DEC's VS11 color graphics devices.

Dewetting of patterned solid films: Towards a predictive modelling approach

NASA Astrophysics Data System (ADS)

Trautmann, M.; Cheynis, F.; Leroy, F.; Curiotto, S.; Pierre-Louis, O.; Müller, P.

2017-06-01

Owing to its ability to produce an assembly of nanoislands with controllable size and locations, the solid state dewetting of patterned films has recently received great attention. A simple Kinetic Monte Carlo model based on two reduced energetic parameters allows one to reproduce experimental observations of the dewetting morphological evolution of patterned films of Si(001) on SiO2 (or SOI for Silicon-on-Insulator) with various pattern designs. Thus, it is now possible to use KMC to drive further experiments and to optimize the pattern shapes to reach a desired dewetted structure. Comparisons between KMC simulations and dewetting experiments, at least for wire-shaped patterns, show that the prevailing dewetting mechanism depends on the wire width.

An Experimental Study of Ignition Effects and Flame Growth Over a Thin Solid Fuel in Low-Speed Concurrent Flow Using Drop-Tower Facilities

NASA Technical Reports Server (NTRS)

Pettegrew, Richard Dale

1996-01-01

An experimental study of ignition and flame growth over a thin solid fuel in oxidizer flow speeds from 0 to 10 cm/sec concurrent flow was performed. This study examined the differences between ignition using a resistively heated wire (woven in a sawtooth pattern over the leading edge of the fuel), and a straight resistively heated wire augmented by a chemical ignitor doped onto the leading edge of the fuel. Results showed that the chemical system yielded non-uniform ignition bursts, while the system using only the hotwire gave more uniform ignition. At speeds up to 2.5 cm/sec, the chemical system yielded non-uniform pyrolysis fronts, while the hotwire system gave more uniform pyrolysis fronts. At speeds of 5 cm/sec or greater, both systems gave uniform pyrolysis fronts. The chemically-ignited flames tended to become too dim to see faster than the hotwire-ignited flames, and the flame lengths were observed to be shorter (after the initial burst subsided) for the chemical system for all speeds. Flame and pyrolysis element velocities were measured. Temperature profiles for selected tests were measured using thermocouples at the fuel surface and in the gas phase. Comparisons between the flame element velocities and peak temperatures recorded in these tests with calculated spread rates and peak temperatures from a steady-state model are presented. Agreement was found to be within 20% for most flame elements for nominal velocities of 5 cm/sec and 7.5 cm/sec.

Dynamic characterization of Galfenol

NASA Astrophysics Data System (ADS)

Scheidler, Justin J.; Asnani, Vivake M.; Deng, Zhangxian; Dapino, Marcelo J.

2015-04-01

A novel and precise characterization of the constitutive behavior of solid and laminated research-grade, polycrystalline Galfenol (Fe81:6Ga18:4) under under quasi-static (1 Hz) and dynamic (4 to 1000 Hz) stress loadings was recently conducted by the authors. This paper summarizes the characterization by focusing on the experimental design and the dynamic sensing response of the solid Galfenol specimen. Mechanical loads are applied using a high frequency load frame. The dynamic stress amplitude for minor and major loops is 2.88 and 31.4 MPa, respectively. Dynamic minor and major loops are measured for the bias condition resulting in maximum, quasi-static sensitivity. Three key sources of error in the dynamic measurements are accounted for: (1) electromagnetic noise in strain signals due to Galfenol's magnetic response, (2) error in load signals due to the inertial force of fixturing, and (3) time delays imposed by conditioning electronics. For dynamic characterization, strain error is kept below 1.2 % of full scale by wiring two collocated gauges in series (noise cancellation) and through lead wire weaving. Inertial force error is kept below 0.41 % by measuring the dynamic force in the specimen using a nearly collocated piezoelectric load washer. The phase response of all conditioning electronics is explicitly measured and corrected for. In general, as frequency increases, the sensing response becomes more linear due to an increase in eddy currents. The location of positive and negative saturation is the same at all frequencies. As frequency increases above about 100 Hz, the elbow in the strain versus stress response disappears as the active (soft) regime stiffens toward the passive (hard) regime.

Dynamic Characterization of Galfenol

NASA Technical Reports Server (NTRS)

Scheidler, Justin; Asnani, Vivake M.; Deng, Zhangxian; Dapino, Marcelo J.

2015-01-01

A novel and precise characterization of the constitutive behavior of solid and laminated research-grade, polycrystalline Galfenol (Fe81:6Ga18:4) under under quasi-static (1 Hz) and dynamic (4 to 1000 Hz) stress loadings was recently conducted by the authors. This paper summarizes the characterization by focusing on the experimental design and the dynamic sensing response of the solid Galfenol specimen. Mechanical loads are applied using a high frequency load frame. The dynamic stress amplitude for minor and major loops is 2.88 and 31.4 MPa, respectively. Dynamic minor and major loops are measured for the bias condition resulting in maximum, quasi-static sensitivity. Three key sources of error in the dynamic measurements are accounted for: (1) electromagnetic noise in strain signals due to Galfenol's magnetic response, (2) error in load signals due to the inertial force of fixturing, and (3) time delays imposed by conditioning electronics. For dynamic characterization, strain error is kept below 1.2 % of full scale by wiring two collocated gauges in series (noise cancellation) and through lead wire weaving. Inertial force error is kept below 0.41 % by measuring the dynamic force in the specimen using a nearly collocated piezoelectric load washer. The phase response of all conditioning electronics is explicitly measured and corrected for. In general, as frequency increases, the sensing response becomes more linear due to an increase in eddy currents. The location of positive and negative saturation is the same at all frequencies. As frequency increases above about 100 Hz, the elbow in the strain versus stress response disappears as the active (soft) regime stiffens toward the passive (hard) regime.

Casting of superconducting composite materials (M-4)

NASA Technical Reports Server (NTRS)

Togano, Kazumasa

1993-01-01

An aluminum-lead-bismuth alloy is a flexible alloy and is promising for easily workable embedded-type, filament-dispersed superconducting wire material. It is difficult to produce homogeneous ingots of this material because it is easily separated into elements when melted on Earth due to the large specific gravity differences. In this experiment, a homogeneous alloy will first be produced in molten state in microgravity. It will then be returned to Earth and processed into a wire or tape form. It will then be dispersed as the second phase in micro texture form into the primary phase of aluminum. Superconducting wire material with high-critical-magnetic-field characteristics will be produced. The texture of the material will be observed, and its performance will be evaluated. In addition to the above alloy, a four-element alloy will be produced from silver, a rare Earth element, barium, and copper. The alloys will be oxidized and drawn into wire after being returned to Earth. The materials are expected to be forerunners in obtaining superconducting wire materials from oxide superconductors.

Triclinic-monoclinic-orthorhombic (T-M-O) structural transitions in phase diagram of FeVO4-CrVO4 solid solutions

NASA Astrophysics Data System (ADS)

Bera, Ganesh; Reddy, V. R.; Rambabu, P.; Mal, P.; Das, Pradip; Mohapatra, N.; Padmaja, G.; Turpu, G. R.

2017-09-01

Phase diagram of FeVO4-CrVO4 solid solutions pertinent with structural and magnetic phases is presented with unambiguous experimental evidences. Solid solutions Fe1-xCrxVO4 (0 ≤ x ≤ 1.0) were synthesized through the standard solid state route and studied by X-ray diffraction, scanning electron microscopy, energy dispersive spectra of X-rays, Raman spectroscopy, d.c. magnetization, and 57Fe Mössbauer spectroscopic studies. FeVO4 and CrVO4 were found to be in triclinic (P-1 space group) and orthorhombic structures (Cmcm space group), respectively. Cr incorporation into the FeVO4 lattice leads to the emergence of a new monoclinic phase dissimilar to the both end members of the solid solutions. In Fe1-xCrxVO4 up to x = 0.10, no discernible changes in the triclinic structure were found. A new structural monoclinic phase (C2/m space group) emerges within the triclinic phase at x = 0.125, and with the increase in Cr content, it gets stabilized with clear single phase signatures in the range of x = 0.175-0.25 as evidenced by the Rietveld analysis of the structures. Beyond x = 0.33, orthorhombic phase similar to CrVO4 (Cmcm space group) emerges and coexists with a monoclinic structure up to x = 0.85, which finally tends to stabilize in the range of x = 0.90-1.00. The Raman spectroscopic studies also confirm the structural transition. FeVO4 Raman spectra show the modes related to three nonequivalent V ions in the triclinic structure, where up to 42 Raman modes are observed in the present study. With the stabilization of structures having higher symmetry, the number of Raman modes decreases and the modes related to symmetry inequivalent sites collate into singular modes from the doublet structure. A systematic crossover from two magnetic transitions in FeVO4, at 21.5 K and 15.4 K to single magnetic transition in CrVO4, at 71 K (antiferromagnetic transition), is observed in magnetization studies. The intermediate solid solution with x = 0.15 shows two magnetic transitions, whereas in the compound with x = 0.33 one of the magnetic transitions disappears. 57Fe Mössbauer spectroscopic studies show a finger print evidence for disappearance of non-equivalent sites of Fe as the structure changes from Triclinic-Monoclinic-Orthorhombic phases with the increasing Cr content in Fe1-xCrxVO4. Comprehensive studies related to the structural changes in Fe1-xCrxVO4 solid solutions lead us to detailed phase diagrams which shall be characteristic for room temperature structural and temperature dependent magnetic transitions in these solid solutions, respectively.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rupich, Martin W.; Sathyamurthy, Srivatsan; Fleshler, Steven

We demonstrate a twofold increase in the in-field critical current of AMSC's standard 2G coil wire by irradiation with 18-MeV Au ions. The optimum pinning enhancement is achieved with a dose of 6 × 10 11 Au ions/cm 2. Although the 77 K, self-field critical current is reduced by about 35%, the in-field critical current (H//c) shows a significant enhancement between 4 and 50 K in fields > 1 T. The process was used for the roll-to-roll irradiation of AMSC's standard 46-mm-wide production coated conductor strips, which were further processed into standard copper laminated coil wire. The long-length wires showmore » the same enhancement as attained with short static irradiated samples. The roll-to-roll irradiation process can be incorporated in the standard 2G wire manufacturing, with no modifications to the current process. In conclusion, the enhanced performance of the wire will benefit rotating machine and magnet applications.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rupich, Martin W.; Sathyamurthy, Srivatsan; Fleshler, Steven

We demonstrate a twofold increase in the in-field critical current of AMSC's standard 2G coil wire by irradiation with 18-MeV Au ions. The optimum pinning enhancement is achieved with a dose of 6 x 10(11) Au ions/cm(2). Although the 77 K, self-field critical current is reduced by about 35%, the in-field critical current (H//c) shows a significant enhancement between 4 and 50 K in fields > 1 T. The process was used for the roll-to-roll irradiation of AMSC's standard 46-mm-wide production coated conductor strips, which were further processed into standard copper laminated coil wire. The long-length wires show the samemore » enhancement as attained with short static irradiated samples. The roll-to-roll irradiation process can be incorporated in the standard 2G wire manufacturing, with no modifications to the current process. The enhanced performance of the wire will benefit rotating machine and magnet applications.« less

Charge transfer kinetics at the solid-solid interface in porous electrodes

NASA Astrophysics Data System (ADS)

Bai, Peng; Bazant, Martin Z.

2014-04-01

Interfacial charge transfer is widely assumed to obey the Butler-Volmer kinetics. For certain liquid-solid interfaces, the Marcus-Hush-Chidsey theory is more accurate and predictive, but it has not been applied to porous electrodes. Here we report a simple method to extract the charge transfer rates in carbon-coated LiFePO4 porous electrodes from chronoamperometry experiments, obtaining curved Tafel plots that contradict the Butler-Volmer equation but fit the Marcus-Hush-Chidsey prediction over a range of temperatures. The fitted reorganization energy matches the Born solvation energy for electron transfer from carbon to the iron redox site. The kinetics are thus limited by electron transfer at the solid-solid (carbon-LixFePO4) interface rather than by ion transfer at the liquid-solid interface, as previously assumed. The proposed experimental method generalizes Chidsey’s method for phase-transforming particles and porous electrodes, and the results show the need to incorporate Marcus kinetics in modelling batteries and other electrochemical systems.

Activated microporous materials through polymerization of microemulsion precursors

NASA Astrophysics Data System (ADS)

Venkatesan, Arunkumar

Microemulsions have been well studied for their unique characteristics. They are isotropic, thermodynamically stable and microstructured mixtures of oil and water stabilized by one or more surfactant species. They are formed spontaneously and are thermodynamically stable. Microemulsion precursors can be polymerized to make microporous solids with controlled pore structure and sizes. These polymeric solids have been studied extensively in the past. Although the fundamental properties of the microporous solids have been studied in depth, the development of specific applications that will utilize the unique properties of these solids has not been exhaustively researched. The current work establishes the feasibility of making activated microporous solids from microemulsion precursors, by the use of a ligand that chelates metals and also attaches itself to the polymer monolith. It also uses a novel 'in-situ' incorporation by combining the formulation and incorporation steps into one. The research objectives are, to formulate a microemulsion system that can yield useful microporous solids upon polymerization and activation, to characterize these solids using existing techniques available for analysis of similar microporous solids, to identify and understand the effect of the variables in the system and to study the influence of these variables on the performance characteristics of this material. Characterization techniques like Differential Scanning Calorimetry, Thermogravimetric Analysis and Scanning Electron Microscopy were used. A hydroxyethylmethylmethacrylate/methylmethacrylate/aqueous phase containing 10% SDS' system was chosen as the precursor microemulsion and the corresponding microporous solids were made. A metal chelating ligand, Congo Red, was incorporated onto the microporous polymer using NaOH as a binding agent. The ability of the resultant 'activated' microporous solid to remove metal ions from solution, was evaluated. The metal ion chosen was chromium and the influence of variables such as NaOH loading, Congo Red loading, Cross linker content etc. were studied. It was found that the microporous solids were effective in removing chromium from solution. They outperformed similar polymeric solids with ligands (reported in literature) in chromium removal. A removal of about 1500 micro moles of chromium ions per gram of dry polymer from a solution of 5 mMol/L initial concentration of chromium was observed. This is much more than the removal of 340 micro moles/gram of dry polymer reported in literature for comparable non-microporous systems.

Laser Indirect Shock Welding of Fine Wire to Metal Sheet

PubMed Central

Wang, Xiao; Huang, Tao; Luo, Yapeng; Liu, Huixia

2017-01-01

The purpose of this paper is to present an advanced method for welding fine wire to metal sheet, namely laser indirect shock welding (LISW). This process uses silica gel as driver sheet to accelerate the metal sheet toward the wire to obtain metallurgical bonding. A series of experiments were implemented to validate the welding ability of Al sheet/Cu wire and Al sheet/Ag wire. It was found that the use of a driver sheet can maintain high surface quality of the metal sheet. With the increase of laser pulse energy, the bonding area of the sheet/wire increased and the welding interfaces were nearly flat. Energy dispersive spectroscopy (EDS) results show that the intermetallic phases were absent and a short element diffusion layer which would limit the formation of the intermetallic phases emerging at the welding interface. A tensile shear test was used to measure the mechanical strength of the welding joints. The influence of laser pulse energy on the tensile failure modes was investigated, and two failure modes, including interfacial failure and failure through the wire, were observed. The nanoindentation test results indicate that as the distance to the welding interface decreased, the microhardness increased due to the plastic deformation becoming more violent. PMID:28895900

Transition mechanism of sH to filled-ice Ih structure of methane hydrate under fixed pressure condition

NASA Astrophysics Data System (ADS)

Kadobayashi, H.; Hirai, H.; Ohfuji, H.; Kojima, Y.; Ohishi, Y.; Hirao, N.; Ohtake, M.; Yamamoto, Y.

2017-10-01

The phase transition mechanism of methane hydrate from sH to filled-ice Ih structure was examined using a combination of time-resolved X-ray diffractometry (XRD) and Raman spectroscopy in conjunction with charge-coupled device (CCD) camera observation under fixed pressure conditions. Prior to time-resolved Raman experiments, the typical C-H vibration modes and their pressure dependence of three methane hydrate structures, fluid methane and solid methane were measured using Raman spectroscopy to distinguish the phase transitions of methane hydrates from decomposition to solid methane and ice VI or VII. Experimental results by XRD, Raman spectroscopy and CCD camera observation revealed that the structural transition of sH to filled-ice Ih occurs through a collapse of the sH framework followed by the release of fluid methane that is then gradually incorporated into the filled-ice Ih to reconstruct its structure. These observations suggest that the phase transition of sH to filled-ice Ih takes place by a typical reconstructive mechanism.

Comparison between wire mesh sensor and gamma densitometry void measurements in two-phase flows

NASA Astrophysics Data System (ADS)

Sharaf, S.; Da Silva, M.; Hampel, U.; Zippe, C.; Beyer, M.; Azzopardi, B.

2011-10-01

Wire mesh sensors (WMS) are fast imaging instruments that are used for gas-liquid and liquid-liquid two-phase flow measurements and experimental investigations. Experimental tests were conducted at Helmholtz-Zentrum Dresden-Rossendorf to test both the capacitance and conductance WMS against a gamma densitometer (GD). A small gas-liquid test facility was utilized. This consisted of a vertical round pipe approximately 1 m in length, and 50 mm internal diameter. A 16 × 16 WMS was used with high spatial and temporal resolutions. Air-deionized water was the two-phase mixture. The gas superficial velocity was varied between 0.05 m s-1 and 1.4 m s-1 at two liquid velocities of 0.2 and 0.7 m s-1. The GD consisted of a collimated source and a collimated detector. The GD was placed on a moving platform close to the plane of wires of the sensor, in order to align it accurately using a counter mechanism, with each of the wires of the WMS, and the platform could scan the full section of the pipe. The WMS was operated as a conductivity WMS for a half-plane with eight wires and as a capacitance WMS for the other half. For the cross-sectional void (time and space averaged), along each wire, there was good agreement between WMS and the GD chordal void fraction near the centre of the pipe.

Metal-organic frameworks for analytical chemistry: from sample collection to chromatographic separation.

PubMed

Gu, Zhi-Yuan; Yang, Cheng-Xiong; Chang, Na; Yan, Xiu-Ping

2012-05-15

In modern analytical chemistry researchers pursue novel materials to meet analytical challenges such as improvements in sensitivity, selectivity, and detection limit. Metal-organic frameworks (MOFs) are an emerging class of microporous materials, and their unusual properties such as high surface area, good thermal stability, uniform structured nanoscale cavities, and the availability of in-pore functionality and outer-surface modification are attractive for diverse analytical applications. This Account summarizes our research on the analytical applications of MOFs ranging from sampling to chromatographic separation. MOFs have been either directly used or engineered to meet the demands of various analytical applications. Bulk MOFs with microsized crystals are convenient sorbents for direct application to in-field sampling and solid-phase extraction. Quartz tubes packed with MOF-5 have shown excellent stability, adsorption efficiency, and reproducibility for in-field sampling and trapping of atmospheric formaldehyde. The 2D copper(II) isonicotinate packed microcolumn has demonstrated large enhancement factors and good shape- and size-selectivity when applied to on-line solid-phase extraction of polycyclic aromatic hydrocarbons in water samples. We have explored the molecular sieving effect of MOFs for the efficient enrichment of peptides with simultaneous exclusion of proteins from biological fluids. These results show promise for the future of MOFs in peptidomics research. Moreover, nanosized MOFs and engineered thin films of MOFs are promising materials as novel coatings for solid-phase microextraction. We have developed an in situ hydrothermal growth approach to fabricate thin films of MOF-199 on etched stainless steel wire for solid-phase microextraction of volatile benzene homologues with large enhancement factors and wide linearity. Their high thermal stability and easy-to-engineer nanocrystals make MOFs attractive as new stationary phases to fabricate MOF-coated capillaries for high-resolution gas chromatography (GC). We have explored a dynamic coating approach to fabricate a MOF-coated capillary for the GC separation of important raw chemicals and persistent organic pollutants with high resolution and excellent selectivity. We have combined a MOF-coated fiber for solid-phase microextraction with a MOF-coated capillary for GC separation, which provides an effective MOF-based tandem molecular sieve platform for selective microextraction and high-resolution GC separation of target analytes in complex samples. Microsized MOFs with good solvent stability are attractive stationary phases for high-performance liquid chromatography (HPLC). These materials have shown high resolution and good selectivity and reproducibility in both the normal-phase HPLC separation of fullerenes and substituted aromatics on MIL-101 packed columns and position isomers on a MIL-53(Al) packed column and the reversed-phase HPLC separation of a wide range of analytes from nonpolar to polar and acidic to basic solutes. Despite the above achievements, further exploration of MOFs in analytical chemistry is needed. Especially, analytical application-oriented engineering of MOFs is imperative for specific applications.

Effect of Reaction Pathway on the Extent and Mechanism of Uranium(VI) Immobilization with Calcium and Phosphate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mehta, Vrajesh S.; Maillot, Fabien; Wang, Zheming

Phosphate addition to subsurface environments contaminated with uranium can be used as an in situ remediation approach. Batch experiments were conducted to evaluate the dependence of the extent and mechanism of uranium uptake on the pathway for reaction with calcium phosphates. At pH 4.0 and 6.0 uranium uptake occurred via autunite (Ca(UO2)(PO4)3) precipitation irrespective of the starting forms of calcium and phosphate. At pH 7.5, the uptake mechanism depended on the nature of the calcium and phosphate. When dissolved uranium, calcium, and phosphate were added simultaneously, uranium was structurally incorporated into a newly formed amorphous calcium phosphate solid. Adsorption wasmore » the dominant removal mechanism for uranium contacted with pre-formed amorphous calcium phosphate solids,. When U(VI) was added to a suspension containing amorphous calcium phosphate solids as well as dissolved calcium and phosphate, then removal occurred through precipitation (57±4 %) of autunite and adsorption (43±4 %) onto calcium phosphate. The solid phase speciation of the uranium was determined using X-ray absorption spectroscopy and laser induced fluorescence spectroscopy. Dissolved uranium, calcium, and phosphate concentrations with saturation index calculations helped identify removal mechanisms and determine thermodynamically favorable solid phases.« less

Analyses of Diamond Wire Sawn Wafers: Effect of Various Cutting Parameters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sopori, Bhushan; Basnyat, Prakash; Devayajanam, Srinivas

We have evaluated surface characteristics of diamond wire cut (DWC) wafers sawn under a variety of cutting parameters. These characteristics include surface roughness, spatial frequencies of surface profiles, phase changes, damage depth, and lateral non-uniformities in the surface damage. Various cutting parameters investigated are: wire size, diamond grit size, reciprocating frequency, feed rate, and wire usage. Spatial frequency components of surface topography/roughness are influenced by individual cutting parameters as manifested by distinct peaks in the Fourier transforms of the Dektak profiles. The depth of damage is strongly controlled by diamond grit size and wire usage and to a smaller degreemore » by the wire size.« less

On the roles of solid wall in the thermal analysis of micro heat pipes

NASA Astrophysics Data System (ADS)

Hung, Yew Mun

Micro heat pipe is a small-scale passive heat transfer device of very high thermal conductance that uses phase change and circulation of its working fluid to transfer thermal energy. Different from conventional heat pipe, a micro heat pipe does not contain any wick structure. In this thesis, a one-dimensional, steady-state mathematical model of a single triangular micro heat pipe is developed, with the main purpose of establishing a series of analytical studies on the roles of the solid wall of micro heat pipes in conjunction with the characterization of the thermal performance under the effects of various design and operational parameters. The energy equation of the solid wall is solved analytically to obtain the temperature distribution. The liquid phase is coupled with the solid wall through the continuity of heat flux at their interface, and the continuity, momentum and energy equations of the liquid and vapour phases, together with the Young-Laplace equation for capillary pressure, are solve numerically to yield the heat and fluid flow characteristics of the micro heat pipe. By coupling this mathematical model with the phase-change interfacial resistance model, the relationships for the axial temperature distributions of the liquid and vapour phases throughout the longitudinal direction of a micro heat pipe are also formulated. Four major aspects associated with the operational performance of micro heat pipes are discussed. Firstly, the investigation of the effects of axial conduction in the solid wall reveals that the presence of the solid wall induces change in the phase-change heat transport of the working fluid besides facilitating axial heat conduction in the solid wall. The analysis also highlights the effects of the thickness and thermal conductivity of the solid wall on the axial temperature distribution of solid wall, in the wake of the effects of the axial heat conduction induced on the phase-change heat transport of the working fluid. Secondly, analysis on thermal performance and physical phenomena of an overloaded micro heat pipes incorporating the effects of axial conduction in the solid wall is carried out. The thermal effects of the solid material are investigated and it is observed that the behaviour of the solid wall temperature distribution varies drastically as the applied heat load exceeds the heat transport capacity. The abrupt change in the temperature profile of an overloaded micro heat pipe is of considerable practical significance in which the occurrence of dryout can be identified by physically measuring the solid wall temperatures along the axial direction. Thirdly, by taking into account the axial conduction in the solid wall, the effect of gravity on the thermal performance of an inclined micro heat pipe is explored. Attributed to the occurrence of dryout, an abrupt temperature rise is observed at the evaporator end when the micro heat pipe is negatively inclined. Therefore, the orientation of a micro heat pipe can be determined by physically measuring the solid wall temperature. Lastly, by coupling the heat transfer model of phase-change phenomena at the liquid-vapour interface, the model with axial conduction in the solid wall of the micro heat pipe is extended to predict the axial liquid and vapour temperature distributions of the working fluid, which is useful for the verification of certain assumptions made in the derivation of the mathematical model besides for analyzing the heat transfer characteristics of the evaporation process.

A comparison study of exploding a Cu wire in air, water, and solid powders

NASA Astrophysics Data System (ADS)

Han, Ruoyu; Wu, Jiawei; Ding, Weidong; Zhou, Haibin; Qiu, Aici; Wang, Yanan

2017-11-01

In this paper, an experimental study on exploding a copper wire in air, water, incombustible powders, and energetic materials is performed. We examined the effects of the surrounding media on the explosion process and its related phenomena. Experiments were first carried out with copper wire explosions driven by microsecond timescale pulsed currents in air, water, and the half-half case. Then, the copper wires were exploded in air, water, SiO2 powders, quartz sand, NaCl powders, and energetic-material cylinders, respectively. Our experimental results indicated that the explosion process was significantly influenced by the surrounding media, resulting in noticeable differences in energy deposition, optical emission, and shock waves. In particular, incombustible powders could throttle the current flow completely when a fine wire was adopted. We also found that an air or incombustible-powder layer could drastically attenuate the shock wave generated by a wire explosion. As for energetic-material loads, obvious discrepancies were found in voltage/current waveforms from vaporization when compared with a wire explosion in air/water, which meant the metal vapor/liquid drops play a significant role in the ignition process.

Development of a Flapping Wing Design Incorporating Shape Memory Alloy Actuation

DTIC Science & Technology

2010-03-01

blimp platform. The Methodology section describes the manner in which functional kinematics of Nitinol were determined, the design and fabrication...functional kinematics of Nitinol . The direction of this research aimed at quantifying the stroke length of selected diameter Nitinol wires as a function...of cycling rate. Several Nitinol wires, trademarked as FlexinolTM and advertised as 50:50 Nickel-Titanium in composition, were purchased online

Nanolayered Features of Collagen-like Peptides

NASA Technical Reports Server (NTRS)

Valluzzi, Regina; Bini, Elisabetta; Haas, Terry; Cebe, Peggy; Kaplan, David L.

2003-01-01

We have been investigating collagen-like model oligopeptides as molecular bases for complex ordered biomimetic materials. The collagen-like molecules incorporate aspects of native collagen sequence and secondary structure. Designed modifications to native primary and secondary structure have been incorporated to control the nanostructure and microstructure of the collagen-like materials produced. We find that the collagen-like molecules form a number of lyotropic rod liquid crystalline phases, which because of their strong temperature dependence in the liquid state can also be viewed as solvent intercalated thermotropic liquid crystals. The liquid crystalline phases formed by the molecules can be captured in the solid state by drying off solvent, resulting in solid nanopatterned (chemically and physically) thermally stable (to greater than 100 C) materials. Designed sequences which stabilize smectic phases have allowed a variety of nanoscale multilayered biopolymeric materials to be developed. Preliminary investigations suggest that chemical patterns running perpendicular to the smectic layer plane can be functionalized and used to localize a variety of organic, inorganic, and organometallic moieties in very simple multilayered nanocomposites. The phase behavior of collagen-like oligopeptide materials is described, emphasizing the correlation between mesophase, molecular orientation, and chemical patterning at the microscale and nanoscale. In many cases, the textures observed for smectic and hexatic phase collagens are remarkably similar to the complex (and not fully understood) helicoids observed in biological collagen-based tissues. Comparisons between biological morphologies and collagen model liquid crystalline (and solidified materials) textures may help us understand the molecular features which impart order and function to the extracellular matrix and to collagen-based mineralized tissues. Initial studies have utilized synthetic collagen-like peptides while future work will also focus on similar sequences generated via genetic engineering methods.

Energy efficient engine high-pressure turbine single crystal vane and blade fabrication technology report

NASA Technical Reports Server (NTRS)

Giamei, A. F.; Salkeld, R. W.; Hayes, C. W.

1981-01-01

The objective of the High-Pressure Turbine Fabrication Program was to demonstrate the application and feasibility of Pratt & Whitney Aircraft-developed two-piece, single crystal casting and bonding technology on the turbine blade and vane configurations required for the high-pressure turbine in the Energy Efficient Engine. During the first phase of the program, casting feasibility was demonstrated. Several blade and vane halves were made for the bonding trials, plus solid blades and vanes were successfully cast for materials evaluation tests. Specimens exhibited the required microstructure and chemical composition. Bonding feasibility was demonstrated in the second phase of the effort. Bonding yields of 75 percent for the vane and 30 percent for the blade were achieved, and methods for improving these yield percentages were identified. A bond process was established for PWA 1480 single crystal material which incorporated a transient liquid phase interlayer. Bond properties were substantiated and sensitivities determined. Tooling die materials were identified, and an advanced differential thermal expansion tooling concept was incorporated into the bond process.

One step growth of GaN/SiO2 core/shell nanowire in vapor-liquid-solid route by chemical vapor deposition technique

NASA Astrophysics Data System (ADS)

Barick, B. K.; Yadav, Shivesh; Dhar, S.

2017-11-01

GaN/SiO2 core/shell nanowires are grown by cobalt phthalocyanine catalyst assisted vapor-liquid-solid route, in which Si wafer coated with a mixture of gallium and indium is used as the source for Ga and Si and ammonia is used as the precursor for nitrogen and hydrogen. Gallium in the presence of indium and hydrogen, which results from the dissociation of ammonia, forms Si-Ga-In alloy at the growth temperature ∼910 °C. This alloy acts as the source of Si, Ga and In. A detailed study using a variety of characterization tools reveals that these wires, which are several tens of micron long, has a diameter distribution of the core ranging from 20 to 50 nm, while the thickness of the amorphous SiO2 shell layer is about 10 nm. These wires grow along [ 1 0 1 bar 0 ] direction. It has also been observed that the average diameter of these wires decreases, while their density increases as the gallium proportion in the Ga-In mixture is increased.

Droplet monitoring probe

NASA Technical Reports Server (NTRS)

Baughman, J. R.; Thys, P. C.

1973-01-01

A droplet monitoring system is disclosed for analysis of mixed-phase fluid flow in development of gas turbines. The system uses a probe comprising two electrical wires spaced a known distance apart and connected at one end to means for establishing a dc potential between the wires. A drop in the fluid stream momentarily contacting both wires simultaneously causes and electrical signal which is amplified, detected and counted.

Depositing High-T(sub c) Superconductors On Normal-Conductor Wires

NASA Technical Reports Server (NTRS)

Kirlin, Peter S.

1994-01-01

Experiments have demonstrated feasibility of depositing thin layers of high-T(sub c) superconductor on normally electrically conductive wires. Superconductivity evident at and below critical temperature (T{sub c}) of 71 K. OMCVD, organometallic vapor deposition, apparatus coats Ag wire with layer high-T(sub c) superconductor. Superconductive phase of this material formed subsequently by annealing under controlled conditions.

Analytical methods to characterize heterogeneous raw material for thermal spray process: cored wire Inconel 625

NASA Astrophysics Data System (ADS)

Lindner, T.; Bonebeau, S.; Drehmann, R.; Grund, T.; Pawlowski, L.; Lampke, T.

2016-03-01

In wire arc spraying, the raw material needs to exhibit sufficient formability and ductility in order to be processed. By using an electrically conductive, metallic sheath, it is also possible to handle non-conductive and/or brittle materials such as ceramics. In comparison to massive wire, a cored wire has a heterogeneous material distribution. Due to this fact and the complex thermodynamic processes during wire arc spraying, it is very difficult to predict the resulting chemical composition in the coating with sufficient accuracy. An Inconel 625 cored wire was used to investigate this issue. In a comparative study, the analytical results of the raw material were compared to arc sprayed coatings and droplets, which were remelted in an arc furnace under argon atmosphere. Energy-dispersive X-ray spectroscopy (EDX) and X-ray fluorescence (XRF) analysis were used to determine the chemical composition. The phase determination was performed by X-ray diffraction (XRD). The results were related to the manufacturer specifications and evaluated in respect to differences in the chemical composition. The comparison between the feedstock powder, the remelted droplets and the thermally sprayed coatings allows to evaluate the influence of the processing methods on the resulting chemical and phase composition.

Deliberate and Accidental Gas-Phase Alkali Doping of Chalcogenide Semiconductors: Cu(In,Ga)Se2

PubMed Central

Colombara, Diego; Berner, Ulrich; Ciccioli, Andrea; Malaquias, João C.; Bertram, Tobias; Crossay, Alexandre; Schöneich, Michael; Meadows, Helene J.; Regesch, David; Delsante, Simona; Gigli, Guido; Valle, Nathalie; Guillot, Jérome; El Adib, Brahime; Grysan, Patrick; Dale, Phillip J.

2017-01-01

Alkali metal doping is essential to achieve highly efficient energy conversion in Cu(In,Ga)Se2 (CIGSe) solar cells. Doping is normally achieved through solid state reactions, but recent observations of gas-phase alkali transport in the kesterite sulfide (Cu2ZnSnS4) system (re)open the way to a novel gas-phase doping strategy. However, the current understanding of gas-phase alkali transport is very limited. This work (i) shows that CIGSe device efficiency can be improved from 2% to 8% by gas-phase sodium incorporation alone, (ii) identifies the most likely routes for gas-phase alkali transport based on mass spectrometric studies, (iii) provides thermochemical computations to rationalize the observations and (iv) critically discusses the subject literature with the aim to better understand the chemical basis of the phenomenon. These results suggest that accidental alkali metal doping occurs all the time, that a controlled vapor pressure of alkali metal could be applied during growth to dope the semiconductor, and that it may have to be accounted for during the currently used solid state doping routes. It is concluded that alkali gas-phase transport occurs through a plurality of routes and cannot be attributed to one single source. PMID:28233864

Deliberate and Accidental Gas-Phase Alkali Doping of Chalcogenide Semiconductors: Cu(In,Ga)Se2.

PubMed

Colombara, Diego; Berner, Ulrich; Ciccioli, Andrea; Malaquias, João C; Bertram, Tobias; Crossay, Alexandre; Schöneich, Michael; Meadows, Helene J; Regesch, David; Delsante, Simona; Gigli, Guido; Valle, Nathalie; Guillot, Jérome; El Adib, Brahime; Grysan, Patrick; Dale, Phillip J

2017-02-24

Alkali metal doping is essential to achieve highly efficient energy conversion in Cu(In,Ga)Se 2 (CIGSe) solar cells. Doping is normally achieved through solid state reactions, but recent observations of gas-phase alkali transport in the kesterite sulfide (Cu 2 ZnSnS 4 ) system (re)open the way to a novel gas-phase doping strategy. However, the current understanding of gas-phase alkali transport is very limited. This work (i) shows that CIGSe device efficiency can be improved from 2% to 8% by gas-phase sodium incorporation alone, (ii) identifies the most likely routes for gas-phase alkali transport based on mass spectrometric studies, (iii) provides thermochemical computations to rationalize the observations and (iv) critically discusses the subject literature with the aim to better understand the chemical basis of the phenomenon. These results suggest that accidental alkali metal doping occurs all the time, that a controlled vapor pressure of alkali metal could be applied during growth to dope the semiconductor, and that it may have to be accounted for during the currently used solid state doping routes. It is concluded that alkali gas-phase transport occurs through a plurality of routes and cannot be attributed to one single source.

Sensors for monitoring waste glass quality and method of using the same

DOEpatents

Bickford, Dennis F.

1994-01-01

A set of three electrical probes for monitoring alkali and oxygen activity of a glass melt. On-line, real time measurements of the potential difference among the probes when they are placed in electrical contact with the melt yield the activity information and can be used to adjust the composition of the melt in order to produce higher quality glass. The first two probes each has a reference gas and a reference electrolyte and a pair of wires in electrical connection with each other in the reference gas but having one of the wires extending further into the reference electrolyte. The reference gases both include a known concentration of oxygen. The third electrode has a pair of wires extending through an otherwise solid body to join electrically just past the body but having one of the wires extend past this junction. Measuring the potential difference between wires of the first and second probes provides the alkali activity; measurement of the potential difference between wires of the second and third probes provides the oxygen activity of the melt.

Sensors for monitoring waste glass quality and method of using the same

DOEpatents

Bickford, D.F.

1994-03-15

A set of three electrical probes is described for monitoring alkali and oxygen activity of a glass melt. On-line, real time measurements of the potential difference among the probes when they are placed in electrical contact with the melt yield the activity information and can be used to adjust the composition of the melt in order to produce higher quality glass. The first two probes each has a reference gas and a reference electrolyte and a pair of wires in electrical connection with each other in the reference gas but having one of the wires extending further into the reference electrolyte. The reference gases both include a known concentration of oxygen. The third electrode has a pair of wires extending through an otherwise solid body to join electrically just past the body but having one of the wires extend past this junction. Measuring the potential difference between wires of the first and second probes provides the alkali activity; measurement of the potential difference between wires of the second and third probes provides the oxygen activity of the melt. 1 figure.

Metallurgical investigation of wire breakage of tyre bead grade.

PubMed

Palit, Piyas; Das, Souvik; Mathur, Jitendra

2015-10-01

Tyre bead grade wire is used for tyre making application. The wire is used as reinforcement inside the polymer of tyre. The wire is available in different size/section such as 1.6-0.80 mm thin Cu coated wire. During tyre making operation at tyre manufacturer company, wire failed frequently. In this present study, different broken/defective wire samples were collected from wire mill for detailed investigation of the defect. The natures of the defects were localized and similar in nature. The fracture surface was of finger nail type. Crow feet like defects including button like surface abnormalities were also observed on the broken wire samples. The defect was studied at different directions under microscope. Different advanced metallographic techniques have been used for detail investigation. The analysis revealed that, white layer of surface martensite was formed and it caused the final breakage of wire. In this present study we have also discussed about the possible reason for the formation of such kind of surface martensite (hard-phase).

Reliability improvement of 1 mil aluminum wire bonds for semiconductors, technical performance summary

NASA Technical Reports Server (NTRS)

1971-01-01

The reliability of semiconductor devices as influenced by the reliability of wire bonds used in the assembly of the devices is investigated. The specific type of failure dealt with involves fracture of wire bonds as a result of repeated flexure of the wire at the heel of the bond when the devices are operated in an on-off mode. The mechanism of failure is one of induced fracture of the wire. To improve the reliability of a chosen transistor, one-mil diameter wires of aluminum with various alloy additions were studied using an accelerated fatigue testing machine. In addition, the electroprobe was used to study the metallurgy of the wires as to microstructure and kinetics of the growth of insoluble phases. Thermocompression and ultrasonic bonding techniques were also investigated.

Method for starting operation of a resistance melter

DOEpatents

Chapman, Christopher Charles

1977-01-01

A method for starting the operation of a resistance furnace, where heating occurs by passing a current through the charge between two furnace electrodes and the charge is a material which is essentially electrically nonconductive when in a solid physical state but which becomes more electrically conductive when in a molten physical state, by connecting electrical resistance heating wire between the furnace electrodes, placing the wire in contact with the charge material between the electrodes and passing a current through the wire to heat the wire to a temperature sufficient to melt the material between the furnace electrodes so that as the material melts, current begins to pass between the electrodes through the melted material, further heating and melting more material until all current between the electrodes passes through the charge material without the aid or presence of the resistance element.

Hot wire anemometer measurements in the unheated air flow tests of the SRB nozzle-to-case joint

NASA Technical Reports Server (NTRS)

Ramachandran, N.

1988-01-01

Hot-Wire Anemometer measurements made in the Solid Rocket Booster (SRB) nozzle-to-case joint are discussed. The study was undertaken to glean additional information on the circumferential flow induced in the SRB nozzle joint and the effect of this flow on the insulation bonding flaws. The tests were conducted on a full-scale, 2-D representation of a 65-in long segment of the SRB nozzle joint, with unheated air as the working fluid. Both the flight Mach number and Reynolds number were matched simultaneously and different pressure gradients imposed along the joint face were investigated. Hot-wire anemometers were used to obtain velocity data for different joint gaps and debond configurations. The procedure adopted for hot-wire calibration and use is outlined and the results from the tests summarized.

Structural Characterisation and Mechanical FE Analysis of Conventional and M-Wire Ni-Ti Alloys Used in Endodontic Rotary Instruments

PubMed Central

Montalvão, Diogo; Alçada, Francisca Sena; Braz Fernandes, Francisco Manuel; de Vilaverde-Correia, Sancho

2014-01-01

The purpose of this study is to understand how the M-Wire alloy conditions the mechanical flexibility of endodontic rotary files at body temperature.Two different rotary instruments, a Profile GT 20/.06 and a Profile GT Series X 20/.06, were selected due to their geometrical similarity and their different constituent alloy. GT series X files are made from M-Wire, a Ni-Ti alloy allegedly having higher flexibility at body temperature. Both files were analysed by X-Ray Diffraction and Differential Scanning Calorimetry to investigate phase transformations and the effects of working temperature on these different alloys. Mechanical behaviour was assessed by means of static bending and torsional Finite Element simulations, taking into account the nonlinear superelastic behaviour of Ni-Ti materials. It was found that GT files present austenitic phase at body temperature, whereas GT series X present R-phase at temperatures under 40°C with a potential for larger flexibility. For the same load conditions, simulations showed that the slight geometrical differences between the two files do not introduce great disagreement in the instruments' mechanical response. It was confirmed that M-Wire increases the instrument's flexibility, mainly due to the presence of R-phase at body temperature. PMID:24574937

Structural characterisation and mechanical FE analysis of conventional and M-Wire Ni-Ti alloys used in endodontic rotary instruments.

PubMed

Montalvão, Diogo; Alçada, Francisca Sena; Braz Fernandes, Francisco Manuel; de Vilaverde-Correia, Sancho

2014-01-01

The purpose of this study is to understand how the M-Wire alloy conditions the mechanical flexibility of endodontic rotary files at body temperature.Two different rotary instruments, a Profile GT 20/.06 and a Profile GT Series X 20/.06, were selected due to their geometrical similarity and their different constituent alloy. GT series X files are made from M-Wire, a Ni-Ti alloy allegedly having higher flexibility at body temperature. Both files were analysed by X-Ray Diffraction and Differential Scanning Calorimetry to investigate phase transformations and the effects of working temperature on these different alloys. Mechanical behaviour was assessed by means of static bending and torsional Finite Element simulations, taking into account the nonlinear superelastic behaviour of Ni-Ti materials. It was found that GT files present austenitic phase at body temperature, whereas GT series X present R-phase at temperatures under 40 °C with a potential for larger flexibility. For the same load conditions, simulations showed that the slight geometrical differences between the two files do not introduce great disagreement in the instruments' mechanical response. It was confirmed that M-Wire increases the instrument's flexibility, mainly due to the presence of R-phase at body temperature.

Trace water sensor

NASA Technical Reports Server (NTRS)

Stephens, James B. (Inventor); Yang, Mary M. (Inventor); Laue, Eric G. (Inventor)

1985-01-01

A solid electrolytic type hygrometer is described, which operates with high reliability while providing rapid and sensitive response. A gold foil electrode (16) is wrapped about a hollow glass cylinder (18), a sheet (12) of hygroscopic-electrolytic material is wrapped about the foil, and a wire (14) is wound around the outside of the electrolytic sheet. Moisture passing between wire turns can be absorbed by the electrolytic material (12), and then dissociated by current passed by the electrodes (14, 16) through the electrolytic material. The cylinder has a slit (20) extending along its length, to allow resilient expansion to press the sheet of electrolytic material firmly against the electrodes. The wire turns lie against one another to cause rapid dissociation of moisture throughout the electrolytic material. Additional guard wires (42,44, FIG. 2) lie at opposite ends of the electrolytic sheet, and currents pass through them to avoid moisture buildup at the ends of the main wire coil. The electrical current through the sheet or membrane is proportional to the partial pressure of the water-vapor.

Platinum atomic wire encapsulated in gold nanotubes: A first principle study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nigam, Sandeep, E-mail: snigam@barc.gov.in; Majumder, Chiranjib; Sahoo, Suman K.

2014-04-24

The nanotubes of gold incorporated with platinum atomic wire have been investigated by means of firstprinciples density functional theory with plane wave pseudopotential approximation. The structure with zig-zag chain of Pt atoms in side gold is found to be 0.73 eV lower in energy in comparison to straight chain of platinum atoms. The Fermi level of the composite tube was consisting of d-orbitals of Pt atoms. Further interaction of oxygen with these tubes reveals that while tube with zig-zag Pt prefers dissociative adsorption of oxygen molecule, the gold tube with linear Pt wire favors molecular adsorption.

Factors affecting energy deposition and expansion in single wire low current experiments

NASA Astrophysics Data System (ADS)

Duselis, Peter U.; Vaughan, Jeffrey A.; Kusse, Bruce R.

2004-08-01

Single wire experiments were performed on a low current pulse generator at Cornell University. A 220 nF capacitor charged to 15-25 kV was used to drive single wire experiments. The capacitor and wire holder were connected in series through an external variable inductor to control the current rise rate. This external series inductance was adjustable from 0.2 to 2 μH. When coupled with the range of charging voltages this results in current rise rates from 5 to 50 A/ns. The current heated the wire through liquid and vapor phases until plasma formed around the wire. Energy deposition and expansion rates were measured as functions of the current rise rate. These results indicated better energy deposition and higher expansion rates with faster current rise rates. Effects of the wire-electrode connection method and wire polarity were also studied.

46 CFR 154.801 - Pressure relief systems.

Code of Federal Regulations, 2011 CFR

2011-10-01

... than the MARVS; (3) Have a fitting for sealing wire that prevents the set pressure from being changed without breaking the sealing wire; (4) Be fitted on the cargo tank to remain in the vapor phase under...

46 CFR 154.801 - Pressure relief systems.

Code of Federal Regulations, 2012 CFR

2012-10-01

... than the MARVS; (3) Have a fitting for sealing wire that prevents the set pressure from being changed without breaking the sealing wire; (4) Be fitted on the cargo tank to remain in the vapor phase under...

46 CFR 154.801 - Pressure relief systems.

Code of Federal Regulations, 2013 CFR

2013-10-01

... than the MARVS; (3) Have a fitting for sealing wire that prevents the set pressure from being changed without breaking the sealing wire; (4) Be fitted on the cargo tank to remain in the vapor phase under...

46 CFR 154.801 - Pressure relief systems.

Code of Federal Regulations, 2014 CFR

2014-10-01

... than the MARVS; (3) Have a fitting for sealing wire that prevents the set pressure from being changed without breaking the sealing wire; (4) Be fitted on the cargo tank to remain in the vapor phase under...

Technetium incorporation into goethite (α-FeOOH): An atomic-scale investigation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Frances N.; Taylor, Christopher D.; Um, Wooyong

2015-11-17

During the processing of low-activity radioactive waste to generate solid waste forms (e.g., glass), technetium-99 (Tc) is of concern because of its volatility. A variety of materials are under consideration to capture Tc from waste streams, including the iron oxyhydroxide, goethite (α-FeOOH), which was experimentally shown to sequester Tc(IV). This material could ultimately be incorporated into glass or other low-temperature waste form matrices. However, questions remain regarding the incorporation mechanism for Tc(IV) in goethite, which has implications for predicting the long-term stability of Tc in waste forms under changing conditions. Here, quantum-mechanical calculations were used to evaluate the energy ofmore » five different charge-compensated Tc(IV) incorporation scenarios in goethite. The two most stable incorporation mechanisms involve direct substitution of Tc(IV) onto Fe(III) lattice sites and charge balancing either by removing one nearby H+ (i.e., within 5 Å), or by creating an Fe(III) vacancy when substituting 3 Tc(IV) for 4 Fe(III), with the former being preferred over the latter relative to gas-phase ions. When corrections for hydrated references phases are applied, the Fe(III)-vacancy mechanism becomes more energetically competitive. Calculated incorporation energies and optimized bond-lengths are presented. Proton movement is observed to satisfy under-coordinated bonds surrounding vacancies in the goethite structure.« less

Impact of different welding techniques on biological effect markers in exhaled breath condensate of 58 mild steel welders.

PubMed

Hoffmeyer, Frank; Raulf-Heimsoth, Monika; Lehnert, Martin; Kendzia, Benjamin; Bernard, Sabine; Berresheim, Hans; Düser, Maria; Henry, Jana; Weiss, Tobias; Koch, Holger M; Pesch, Beate; Brüning, Thomas

2012-01-01

Total mass and composition of welding fumes are predominantly dependent on the welding technique and welding wire applied. The objective of this study was to investigate the impact of welding techniques on biological effect markers in exhaled breath condensate (EBC) of 58 healthy welders. The welding techniques applied were gas metal arc welding with solid wire (GMAW) (n=29) or flux cored wire (FCAW) (n=29). Welding fume particles were collected with personal samplers in the breathing zone inside the helmets. Levels of leukotriene B(4) (LTB(4)), prostaglandin E(2) (PGE(2)), and 8-isoprostane (8-iso-PGF(2α)) were measured with immunoassay kits and the EBC pH was measured after deaeration. Significantly higher 8-iso-PGF(2α) concentrations and a less acid pH were detected in EBC of welders using the FCAW than in EBC of welders using the GMAW technique. The lowest LTB(4) concentrations were measured in nonsmoking welders applying a solid wire. No significant influences were found in EBC concentrations of PGE(2) based upon smoking status or type of welding technique. This study suggests an enhanced irritative effect in the lower airways of mild steel welders due to the application of FCAW compared to GMAW, most likely associated with a higher emission of welding fumes.

Effect of Sulfate on Rhenium Partitioning during Melting of Low-Activity Waste Glass Feeds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jin, Tongan; Kim, Dong-Sang; Schweiger, Michael J.

2015-10-01

The volatile loss of technetium-99 (99Tc) is a major concern of the low-activity waste (LAW) vitrification at Hanford. We investigated the incorporation and volatile loss of Re (a nonradioactive surrogate for 99Tc) during batch-to-glass conversion up to 1100°C. The AN-102 feed, which is one of the representative Hanford LAW feeds, containing 0.59 wt% of SO3 (in glass if 100% retained) was used. The modified sulfate-free AN-102_0S feed was also tested to investigate the effect of sulfate on Re partitioning and retention during melting. After heating of the dried melter feed (mixture of LAW simulant and glass forming/modifying additives) to differentmore » temperatures, the heat-treated samples were quenched. For each heat-treated sample, the salts (soluble components in room temperature leaching), early glass forming melt (soluble components in 80°C leaching), and insoluble solids were separated by a two-step leaching and the chemical compositions of each phase were quantitatively analyzed. The final retention ratio of AN-102 and AN-102_0S in glass (insoluble solids) are 32% and 63% respectively. The presence of sulfate in the salt phase between 600 and 800°C leads to a significantly higher Re loss via volatilization from the salt layer. At ≥800°C, for both samples, there is no more incorporation of Re into the insoluble phase because: for AN-102_0S there is no salt left i.e., the split into the insoluble and gas phases is complete by 800°C and for AN-102 all the Re contained in the remaining salt phase is lost through volatilization. The present results on the effect of sulfate, although not directly applicable to LAW vitrification in the melter, will be used to understand the mechanism of Re incorporation into glass to eventually develop the methods that can increase the 99Tc retention during LAW vitrification at Hanford.« less

Update on High-Temperature Coils for Electromagnets

NASA Technical Reports Server (NTRS)

Kascak, Albert F.; Montague, Gerald T.; Palazzolo, Alan; Preuss, Jason; Carter, Bart; Tucker, Randall; Hunt, Andrew

2005-01-01

A report revisits the subject matter of "High-Temperature Coils for Electromagnets" (LEW-17164), NASA Tech Briefs, Vol. 26, No. 8, (August 2002) page 38. To recapitulate: Wires have been developed for use in electromagnets that operate at high temperatures. The starting material for a wire of this type can be either a nickel-clad, ceramic-insulated copper wire or a bare silver wire. The wire is covered by electrical-insulation material that is intended to withstand operating temperatures in the range from 800 to 1,300 F (.430 to .700 C): The starting wire is either primarily wrapped with S-glass as an insulating material or else covered with another insulating material wrapped in S-glass prior to the winding process. A ceramic binding agent is applied as a slurry during the winding process to provide further insulating capability. The turns are pre-bent during winding to prevent damage to the insulation. The coil is then heated to convert the binder into ceramic. The instant report mostly reiterates the prior information and presents some additional information on the application of the ceramic binding agent and the incorporation of high-temperature wire into the windings.

Electro-Optic Fabrics for the Warrior of the 21st Century - Phase II

DTIC Science & Technology

2010-01-01

46 28. Effect of 1000 cycles of hex- abrasion testing on Fire Wire cable .................................... 46 UNCLASSIFIED vi 29. Close...49 32. Effect of 2000 cycles of hex- abrasion testing on Fire Wire cable .................................... 49 33. Effect of 4000 cycles of...hex- abrasion testing on Fire Wire cable .................................... 50 34. Effect of 2000 cycles of hex- abrasion testing on USB v2 cable

Retention of coded wire tags, and their effect on maturation and survival of yellow mealworms (Coleoptera: Tenebrionidae)

USGS Publications Warehouse

Schaffler, James J.; Isely, J.J.

2001-01-01

This study demonstrates that coded wire tags can be used to mark certain insect larvae without adverse effects on maturation, and that tags are retained through the adult phase in high enough proportion for practical application. Coded wire tags also offer the benefit that marked organisms can be identified to the batch or individual level.

Shape-retainment control using an antagonistic shape memory alloy system

NASA Astrophysics Data System (ADS)

Ikeda, T.; Sawamura, K.; Senba, A.; Tamayama, M.

2015-04-01

Since shape memory alloy (SMA) actuators can generate large force per unit weight, they are expected as one of the next generation actuators for aircraft. To keep a position of conventional control surfaces or morphing wings with SMA actuators, the SMA actuators must keep being heated, and the heating energy is not small. To save the energy, a new control method proposed for piezoelectric actuators utilizing hysteresis in deformation [Ikeda and Takahashi, Proc. SPIE 8689 (2013), 86890C] is applied to an antagonistic SMA system. By using the control method any position can be an equilibrium point within hysteresis of stress-strain diagrams. To confirm a feasibility of the control method, a fundamental experiment is performed. The SMA wires are heated by applying electric current to the wires. When a pulsed current is applied to the two SMA wires alternately, the equilibrium position changes between two positions alternately, and when a series of pulse whose amplitude increases gradually is applied to one SMA wire, the equilibrium position changes like a staircase. However, just after the pulse the position returns slightly, that is, overshoot takes place. To investigate such a behavior of the system, numerical simulation is also performed. The one-dimensional phase transformation model [Ikeda, Proc. SPIE 5757 (2005), 344-352] is used for a constitutive model of the SMA wires. The simulated result agrees with the experiment qualitatively, including the overshoot. By examining volume fraction of each phase, it is found that the overshoot is caused by that austenite phase transforms into stress-induced martensite phase during the cooling process after the pulse.

Metallurgical characterization of a new nickel-titanium wire for rotary endodontic instruments.

PubMed

Alapati, Satish B; Brantley, William A; Iijima, Masahiro; Clark, William A T; Kovarik, Libor; Buie, Caesar; Liu, Jie; Ben Johnson, William

2009-11-01

A novel thermomechanical processing procedure has been developed that yields a superelastic (SE) nickel-titanium (NiTi) wire (M-Wire) that laboratory testing shows has improved mechanical properties compared with conventional SE austenitic NiTi wires used for manufacture of rotary instruments. The objective of this study was to determine the origin of the improved mechanical properties. Specimens from 2 batches of M-Wire prepared under different processing conditions and from 1 batch of standard-processed SE wire for rotary instruments were examined by scanning transmission electron microscopy, temperature-modulated differential scanning calorimetry, micro-x-ray diffraction, and scanning electron microscopy with x-ray energy-dispersive spectrometric analyses. The processing for M-Wire yields a microstructure containing martensite, that the proportions of NiTi phases depend on processing conditions, and that the microstructure exhibits pronounced evidence of alloy strengthening. The presence of Ti(2)Ni precipitates in both microstructures indicates that M-Wire and the conventional SE wire for rotary instruments are titanium-rich.

Equation of State for Solid Phase I of Carbon Dioxide Valid for Temperatures up to 800 K and Pressures up to 12 GPa

NASA Astrophysics Data System (ADS)

Martin Trusler, J. P.

2011-12-01

The available thermodynamic-property data for solid phase I of carbon dioxide ("dry ice") are reviewed and used to determine the parameters of a new fundamental equation of state constructed in the form of a Helmholtz energy function with temperature and molar volume as the independent variables. The experimental data considered include the pressure, molar volume, and isobaric heat capacity along the sublimation curve, the melting-pressure curve, and molar volume in the compressed solid at temperatures from 295 to 764 K and pressures up to 12 GPa. The equation of state is based on the quasi-harmonic approximation, incorporating a Debye oscillator distribution for the vibrons, two discrete modes for the librons and a further three distinct modes for the internal vibrations of the CO2 molecule. A small anharmonic correction term is included, which is significant mainly in the region of the triple point. The estimated relative uncertainty of molar volume at specified temperature and pressure calculated from the equation of state is 0.02% on the sublimation curve and 1.5% in the compressed solid; for isobaric heat capacity on the sublimation curve, the uncertainty varies from 5.0% to 0.5% between 2 and 195 K. Auxiliary equations for the pressure and molar volume on the sublimation and melting curves are given. The equation of state is valid at temperatures from 0 to 800 K and at pressures from the solid-fluid phase boundary to 12 GPa.

Effect of fiber blends, total solids, heat treatment, whey protein concentrate and stage of sugar incorporation on dietary fiber-fortified Kheer.

PubMed

Arora, Simran Kaur; Patel, A A

2017-10-01

Owing to the proven beneficial role of dietary fiber (DF) on human health, feasibility of incorporating commercially available soluble and insoluble DF preparations into rice-milk-pudding ( kheer, a popular Indian delicacy) was studied through process modification. The novel approach of preparing reduced fat DF-fortified- kheer (DFFK) by developing liquid/cream phase and particulate/rice phase separately, and subsequently blending the two was developed. The major processing variables studied were total solids (TS) in the liquid phase, type of fiber blend, flavor-simulation through heat treatment or added whey protein, and the presence of sugar in water for pre-cooking of rice. Reduced fat DFFK made from three different pre-standardized fiber blends was quite acceptable to the sensory panel (overall rating 7.5). With increasing TS in milk up to 16.5%, sensory acceptability of DFFK increased. There was a small but perceivable improvement in the flavour of DFFK when precooking of rice was carried out in sweetened water. Reduced fat DFFK from different fiber blends was found to be reasonably close to conventional kheer . DFFK prepared from Blend-I provided 3.31 g dietary fiber/100 kcal (suitable for the claim "High-in-Fiber") with 38.71% Reduced-Fat. With the developed process of fortification of kheer with DF, it is possible to reduce fat (and thus calories) to cater to the needs of consumers seeking good health.

The effect of hydrocarbons on the microstructural evolution in rock salt: a case study on hydrocarbon bearing Ara salt from the South Oman Salt Basin

NASA Astrophysics Data System (ADS)

Schmatz, Joyce; Urai, Janos L.; Wübbeler, Franziska M. M.; Sadler, Marc

2014-05-01

It has been shown that dilatant deformation promotes the incorporation of hydrocarbons into typically low permeable rock salt (Schoenherr et al., 2007). However, there is not much knowledge on subsequent mechanisms related to recrystallization processes, which cause morphological and chemical changes of the carbonic inclusions. This work aims to contribute to an increased understanding of fluid inclusion dynamics related to grain boundary migration recrystallization and hence to facilitate the interpretation of complex microstructures in recrystallized, multiphase salt rocks. In this case study we investigate hydrocarbon-impregnated salt from the Cambrian Ara Group in the South Oman Salt Basin. The samples were cored from cm-m thick anhydrite-salt sequences overlying hydrocarbon bearing carbonate stringers in 3300 m depth. The anhydrite layers consist mainly of fine-grained anhydrite, which contains calcite, dolomite, and olivine inclusions. Solid bitumen and lighter hydrocarbon phases are observed in between the anhydrite grains and along cracks. Anhydrite layers host salt veins, which contain fragments of anhydrite. These fragments do not differ in composition or structure from the host material and the related vein microstructures indicate crack-seal mechanisms. Halite in the salt layers is almost entirely recrystallized with solid inclusions consisting of anhydrite, calcite, dolomite and olivine with hydrocarbon-coatings present inside grains and along grain boundaries. Solid inclusions cause pinning indicated by a decreased recrystallized grain size and by the presence of grains with preserved substructures representing earlier deformation phases. We observe two types of carbonic inclusions: I) solid bitumen coatings along grain boundaries and microcracks, interpreted to be incorporated into the salt in an overpressure state that allowed dilatancy of the salt, and II) less degraded, liquid hydrocarbons along grain boundaries in the vicinity of the anhydrite, interpreted to be incorporated into the salt in a subsequent deformation phase. Type II inclusions usually form arrays of isolated inclusions (liquid hydrocarbons, vapor, and aqueous phases in minor proportions) along grain boundaries of the recrystallized grains, presumably formed in a surface-energy controlled shrinking process from thin fluid films. Here, the contact with mobile grain boundaries promoted necking down and decomposition of multiphase inclusions. We present a model, which describes the dynamic behavior of liquid hydrocarbons in mobile grain boundaries after their enclosure into the salt layers. The model is based on numerous microanalytical methods, such as optical microscopy, fluorescence microscopy, cryo-SEM, and EDX. Schoenherr, J., et al. (2007), Limits to the sealing capacity of rock salt: A case study of the infra-Cambrian Ara Salt from the South Oman salt basin, AAPG Bulletin, 91(11), 1541-1557

A Solid Nitrogen Cooled MgB2 “Demonstration” Coil for MRI Applications

PubMed Central

Yao, Weijun; Bascuñán, Juan; Kim, Woo-Seok; Hahn, Seungyong; Lee, Haigun; Iwasa, Yukikazu

2009-01-01

A 700-mm bore superconducting magnet was built and operated in our laboratory to demonstrate the feasibility of newly developed MgB2 superconductor wire for fabricating MRI magnets. The magnet, an assembly of 10 coils each wound with a reacted and s-glass insulated wire ~1-km long, was immersed in solid nitrogen rather than in a bath of liquid cryogen. This MgB2 magnet was designed to operate in the temperature range 10–15 K, maintained by a cryocooler. A combination of this “wide” temperature range and immersion of the winding in solid nitrogen enables this magnet to operate under conditions not possible with a low temperature superconductor (LTS) counterpart. Tested individually at 13 K, each coil could carry current up to 100 A. When assembled into the magnet, some coils, however, became resistive, causing the magnet to prematurely quench at currents ranging from 79 A to 88 A, at which point the magnet generated a center field of 0.54 T. Despite the presence of a large volume (50 liters) of solid nitrogen in the cold body, cooldown from 77 K to 10 K went smoothly. PMID:20390056

Studies on copper-yttria nanocomposites: high-energy ball milling versus chemical reduction method.

PubMed

Joshi, P B; Rehani, Bharati; Naik, Palak; Patel, Swati; Khanna, P K

2012-03-01

Oxide dispersion-strengthened copper-base composites are widely used for applications demanding high tensile strength, high hardness along with good electrical and thermal conductivity. Oxides of metals like aluminium, cerium, yttrium and zirconium are often used for this purpose as fine and uniformly distributed dispersoid particles in soft and ductile copper matrix. Such composites find applications as electrical contacts, resistance-welding tips, lead wires, continuous casting moulds, etc. In this investigation an attempt has been made to produce copper-yttria nanocomposites using two different morphologies of copper powder and two different processing routes namely, high-energy milling and in-situ chemical reduction. The synthesized powders were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) for their phase identification and morphological study. The nanocomposite powders in each case were subsequently processed to obtain bulk solids by classical powder metallurgy route of press-sinter-repress. The resultant bulk solid compacts were subjected to property evaluation. The study revealed that the properties of Cu-Y2O3 nanocomposites depend on the processing route used and in turn on the resultant powder morphology.

Composite superconducting wires obtained by high-rate tinning in molten Bi-Pb-Sr-Ca-Cu-O system

NASA Technical Reports Server (NTRS)

Grozav, A. D.; Konopko, L. A.; Leporda, N. I.

1990-01-01

The preparation of high-T(sub c) superconducting long composite wires by short-time tinning of the metal wires in a molten Bi-Pb-Sr-Ca-Cu-O compound is discussed. The application of this method to the high-T(sub c) materials is tested, possibly for the first time. The initial materials used for this experiment were ceramic samples with nominal composition Bi(1.5)Pb(0.5)Sr2Ca2Cu3O(x) and T(sub c) = 80 K prepared by the ordinary solid-state reaction, and industrial copper wires from 100 to 400 microns in diameter and from 0.5 to 1 m long. The continuously moving wires were let through a small molten zone (approximately 100 cubic mm). The Bi-based high-T(sub c) ceramics in a molten state is a viscous liquid and it has a strongly pronounced ability to spread on metal wire surfaces. The maximum draw rate of the Cu-wire, at which a dense covering is still possible, corresponds to the time of direct contact of wire surfaces and liquid ceramics for less than 0.1 s. A high-rate draw of the wire permits a decrease in the reaction of the oxide melt and Cu-wire. This method of manufacture led to the fabrication of wire with a copper core in a dense covering with uniform thickness of about h approximately equal to 5 to 50 microns. Composite wires with h approximately equal to 10 microns (h/d approximately equal to 0.1) sustained bending on a 15 mm radius frame without cracking during flexing.

Ab-initio study of high temperature lattice dynamics of BCC zirconium (β-Zr) and uranium (γ-U)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghosh, Partha S., E-mail: parthasarathi13@gmail.com; Arya, A., E-mail: parthasarathi13@gmail.com; Dey, G. K., E-mail: parthasarathi13@gmail.com

2014-04-24

Using self consistent ab-initio lattice dynamics calculations, we show that bcc structures of Zr and U phases become stable at high temperature by phonon-phonon interactions. The calculated temperature dependent phonon dispersion curve (PDC) of β-Zr match excellently with experimental PDC. But the calculated PDC for γ-U shows negative phonon frequencies even at solid to liquid transition temperature. We show that this discrepancy is due to an overestimation of instability depth of bcc U phase which is removed by incorporation of spin-orbit coupling in the electronic structure calculations.

Intravascular migration of a broken cerclage wire into the left heart.

PubMed

Leonardi, Francesco; Rivera, Fabrizio

2014-10-01

This article describes a patient in whom a broken cerclage wire migrated from the left hip into the left ventricle. A 71-year-old woman was admitted to the authors' hospital for preoperative examination before femoral hernia repair. Chest radiograph showed a metallic wire in the left ventricle. Twenty-four years earlier, she had a revision arthroplasty. During revision surgery, fragments of the osteotomy were fixed to the femur with multiple cerclage wires. During the past 5 years, radiographic follow-up showed progressive multiple ruptures of cerclage wires. The cerclage wiring was not removed because the patient had no related clinical symptoms. Radiograph of the left hip showed a well-fixed cemented acetabular ring and an uncemented femoral stem with a healed trochanteric osteotomy. All cerclage wires were broken into multiple parts, and it was very difficult to determine which part had migrated into the heart. Thoracic computed tomography scan showed wire that had migrated into the anterior left ventricular myocardial wall at the atrioventricular level. The patient had no clinical symptoms. Electrocardiogram showed a normal sinus rhythm and right bundle branch block. Because of the high risk of surgical left ventriculotomy associated with searching for wire that had migrated into the myocardial wall, patient monitoring was planned. Definitive management of this complication constitutes a dilemma. Although this complication is highly unusual, the possibility of intracardiac migration of broken wire should be considered when deciding on prophylactic surgical removal of hardware after fracture or osteotomy healing. Copyright 2014, SLACK Incorporated.

In Vivo Assessment of Phage and Linezolid Based Implant Coatings for Treatment of Methicillin Resistant S. aureus (MRSA) Mediated Orthopaedic Device Related Infections

PubMed Central

Kaur, Sandeep; Harjai, Kusum; Chhibber, Sanjay

2016-01-01

Staphylococcus comprises up to two-thirds of all pathogens in orthopaedic implant infections with two species respectively Staphylococcus aureus and Staphylococcus epidermidis, being the predominate etiological agents isolated. Further, with the emergence of methicillin-resistant S. aureus (MRSA), treatment of S. aureus implant infections has become more difficult, thus representing a devastating complication. Use of local delivery system consisting of S.aureus specific phage along with linezolid (incorporated in biopolymer) allowing gradual release of the two agents at the implant site represents a new, still unexplored treatment option (against orthopaedic implant infections) that has been studied in an animal model of prosthetic joint infection. Naked wire, hydroxypropyl methylcellulose (HPMC) coated wire and phage and /or linezolid coated K-wire were surgically implanted into the intra-medullary canal of mouse femur bone of respective groups followed by inoculation of S.aureus ATCC 43300(MRSA). Mice implanted with K-wire coated with both the agents i.e phage as well as linezolid (dual coated wires) showed maximum reduction in bacterial adherence, associated inflammation of the joint as well as faster resumption of locomotion and motor function of the limb. Also, all the coating treatments showed no emergence of resistant mutants. Use of dual coated implants incorporating lytic phage (capable of self-multiplication) as well as linezolid presents an attractive and aggressive early approach in preventing as well as treating implant associated infections caused by methicillin resistant S. aureus strains as assessed in a murine model of experimental joint infection. PMID:27333300

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kabalka, George W

The goal of this research was on the development of new, rapid, and efficient synthetic methods for incorporating short-lived radionuclides into agents of use in measuring dynamic processes. The initial project period (Year 1) was focused on the preparation of stable, solid state precursors that could be used to efficiently incorporate short-lived radioisotopes into small molecules of use in biological applications (environmental, plant, and animal). The investigation included development and evaluation of new methods for preparing carbon-carbon and carbon-halogen bonds for use in constructing the substrates to be radiolabeled. The second phase (Year 2) was focused on developing isotope incorporationmore » techniques using the stable, boronated polymeric precursors. The final phase (Year 3), was focused on the preparation of specific radiolabeled agents and evaluation of their biodistribution using micro-PET and micro-SPECT. In addition, we began the development of a new series of polymeric borane reagents based on polyethylene glycol backbones.« less

Phase diagram of the frustrated J 1 ‑ J 2 transverse field Ising model on the square lattice

NASA Astrophysics Data System (ADS)

Sadrzadeh, M.; Langari, A.

2018-03-01

We study the zero-temperature phase diagram of transverse field Ising model on the J 1 ‑ J 2 square lattice. In zero magnetic field, the model has a classical Néel phase for J 2/J 1 < 0.5 and an antiferromagnetic collinear phase for J 2/J 1 > 0.5. We incorporate harmonic fluctuations by using linear spin wave theory (LSWT) with single spin flip excitations above a magnetic order background and obtain the phase diagram of the model in this approximation. We find that harmonic quantum fluctuations of LSWT fail to lift the large degeneracy at J 2/J 1 = 0.5 and exhibit some inconsistent regions on the phase diagram. However, we show that anharmonic fluctuations of cluster operator approach (COA) resolve the inconsistency of the LSWT, which reveals a string-valence bond solid ordered phase for the highly frustrated region.

Memory alloy heat engine and method of operation

DOEpatents

Johnson, Alfred Davis

1977-01-01

A heat engine and method of operation employing an alloy having a shape memory effect. A memory alloy element such as one or more wire loops are cyclically moved through a heat source, along a path toward a heat sink, through the heat sink and then along another path in counter-flow heat exchange relationship with the wire in the first path. The portion of the wire along the first path is caused to elongate to its trained length under minimum tension as it is cooled. The portion of the wire along the second path is caused to contract under maximum tension as it is heated. The resultant tension differential between the wires in the two paths is applied as a force through a distance to produce mechanical work. In one embodiment a first set of endless memory alloy wires are reeved in non-slip engagement between a pair of pulleys which are mounted for conjoint rotation within respective hot and cold reservoirs. Another set of endless memory alloy wires are reeved in non-slip engagement about another pair of pulleys which are mounted in the respective hot and cold reservoirs. The pulleys in the cold reservoir are of a larger diameter than those in the hot reservoir and the opposite reaches of the wires between the two sets of pulleys extend in closely spaced-apart relationship in counter-flow heat regenerator zones. The pulleys are turned to move the two sets of wires in opposite directions. The wires are stretched as they are cooled upon movement through the heat regenerator toward the cold reservoirs, and the wires contract as they are heated upon movement through the regenerator zones toward the hot reservoir. This contraction of wires exerts a larger torque on the greater diameter pulleys for turning the pulleys and supplying mechanical power. Means is provided for applying a variable tension to the wires. Phase change means is provided for controlling the angular phase of the pulleys of each set for purposes of start up procedure as well as for optimizing engine operation under varying conditions of load, speed and temperatures.

Thermal Dispersion Within a Porous Medium Near a Solid Wall

NASA Technical Reports Server (NTRS)

Simon, T.; McFadden, G.; Ibrahim, M.

2006-01-01

The regenerator is a key component to Stirling cycle machine efficiency. Typical regenerators are of sintered fine wires or layers of fine-wire screens. Such porous materials are contained within solid-waH casings. Thermal energy exchange between the regenerator and the casing is important to cycle performance for the matrix and casing would not have the same axial temperature profile in an actual machine. Exchange from one to the other may allow shunting of thermal energy, reducing cycle efficiency. In this paper, temperature profiles within the near-wall region of the matrix are measured and thermal energy transport, termed thermal dispersion, is inferred. The data show how the wall affects thermal transport. Transport normal to the mean flow direction is by conduction within the solid and fluid and by advective transport within the matrix. In the near-wall region, both may be interrupted from their normal in-core pattern. Solid conduction paths are broken and scales of advective transport are damped. An equation is presented which describes this change for a wire screen mesh. The near-wall layer typically acts as an insulating layer. This should be considered in design or analysis. Effective thermal conductivity within the core is uniform. In-core transverse thermal effective conductivity values are compared to direct and indirect measurements reported elsewhere and to 3D numerical simulation results, computed previously and reported elsewhere. The 3-D CFD model is composed of six cylinders in cross flow, staggered in arrangement to match the dimensions and porosity of the matrix used in the experiments. The commercial code FLUENT is used to obtain the flow and thermal fields. The thermal dispersion and effective thermal conductivities for the matrix are computed from the results.

Rapid Screening of Volatile Organic Compounds from Aframomum danielli Seeds Using Headspace Solid Phase Microextraction Coupled to Gas Chromatography Mass Spectrometry

PubMed Central

Njobeh, Patrick B.; Gbashi, Sefater; Adegoke, Gabriel O.; Dubery, Ian A.

2018-01-01

Volatile organic compounds (VOCs) derived from plants have been used in the fragrance industry since time immemorial. Herein we report on the rapid screening of VOCs from seeds of ripe Aframomum danielli (family, Zingiberaceae) using a polydimethylsiloxane fibre headspace solid phase microextraction coupled to a gas chromatography mass spectrometry (SPME-GC/MS) instrument. Portions of 0.25, 0.35, and 0.50 g of ground sample were weighed and extraction of volatile organic compounds (VOCs) was achieved using a 100 μm polydimethylsiloxane solid phase microextraction (PDMS SPME) fibre, with the equilibrium time of 40 minutes and extraction temperature of 50°C; the following compounds with their respective relative abundances were obtained as the top ten most abundant and annotated ones using NIST, Wiley, and Fragrances Libraries: eucalyptol (58%); β-pinene (22%); α-pinene (7.5%); α-terpineol (4%), α-terpinyl acetate (2%); α-bergamotene (1%); pinocarveol (0.39%); α-copaene (0.35%); caryophyllene (0.34); and β-bisabolene (0.31%). These compounds have been reported elsewhere in the literature and listed in the Fragrances Library, incorporated into the Saturn QP2020 GCMS Solution® software used for their analysis. PMID:29849643

Solution of magnetohydrodynamic flow and heat transfer of radiative viscoelastic fluid with temperature dependent viscosity in wire coating analysis

PubMed Central

Khan, Muhammad Altaf; Siddiqui, Nasir; Ullah, Murad; Shah, Qayyum

2018-01-01

Wire coating process is a continuous extrusion process for primary insulation of conducting wires with molten polymers for mechanical strength and protection in aggressive environments. In the present study, radiative melt polymer satisfying third grade fluid model is used for wire coating process. The effect of magnetic parameter, thermal radiation parameter and temperature dependent viscosity on wire coating analysis has been investigated. Reynolds model and Vogel’s models have been incorporated for variable viscosity. The governing equations characterizing the flow and heat transfer phenomena are solved analytically by utilizing homotopy analysis method (HAM). The computed results are also verified by ND-Solve method (Numerical technique) and Adomian Decomposition Method (ADM). The effect of pertinent parameters is shown graphically. In addition, the instability of the flow in the flows of the wall of the extrusion die is well marked in the case of the Vogel model as pointed by Nhan-Phan-Thien. PMID:29596448

X-ray diffraction study of low-temperature phase transformations in nickel-titanium orthodontic wires.

PubMed

Iijima, M; Brantley, W A; Guo, W H; Clark, W A T; Yuasa, T; Mizoguchi, I

2008-11-01

Employ conventional X-ray diffraction (XRD) to analyze three clinically important nickel-titanium orthodontic wire alloys over a range of temperatures between 25 and -110 degrees C, for comparison with previous results from temperature-modulated differential scanning calorimetry (TMDSC) studies. The archwires selected were 35 degrees C Copper Ni-Ti (Ormco), Neo Sentalloy (GAC International), and Nitinol SE (3M Unitek). Neo Sentalloy, which exhibits superelastic behavior, is marketed as having shape memory in the oral environment, and Nitinol SE and 35 degrees C Copper Ni-Ti also exhibit superelastic behavior. All archwires had dimensions of 0.016in.x0.022in. (0.41 mm x 0.56 mm). Straight segments cut with a water-cooled diamond saw were placed side-by-side to yield a 1 cm x 1cm test sample of each wire product for XRD analysis (Rint-Ultima(+), Rigaku) over a 2theta range from 30 degrees to 130 degrees and at successive temperatures of 25, -110, -60, -20, 0 and 25 degrees C. The phases revealed by XRD at the different analysis temperatures were in good agreement with those found in previous TMDSC studies of transformations in these alloys, in particular verifying the presence of R-phase at 25 degrees C. Precise comparisons are not possible because of the approximate nature of the transformation temperatures determined by TMDSC and the preferred crystallographic orientation present in the wires. New XRD peaks appear to result from low-temperature transformation in martensite, which a recent transmission electron microscopy (TEM) study has shown to arise from twinning. While XRD is a useful technique to study phases in nickel-titanium orthodontic wires and their transformations as a function of temperature, optimum insight is obtained when XRD analyses are combined with complementary TMDSC and TEM study of the wires.

Application of Ultrasonic Guided Waves for Evaluating Aging Wire Insulation

NASA Technical Reports Server (NTRS)

Anastasi, Robert F.; Madaras, Eric I.

2005-01-01

Aging wiring has become a critical issue to the aerospace and aircraft industries due to Shuttle and aircraft incidents. The problem is that over time the insulation on wire becomes brittle and cracks. This exposes the underlying conductive wire to the potential for short circuits and fire. Popular methods of monitoring aging wire problems focuses on applying electrical sensing techniques that are sensitive to the conductor's condition, but not very sensitive to the wire insulation's condition. Measurement of wire insulation stiffness and ultrasonic properties by ultrasonic guided waves is being examined. Experimental measurements showed that the lowest order extensional mode could be sensitive to stiffness changes in the wire insulation. To test this theory conventional wire samples were heat damaged in an oven, in a range of heating conditions. The samples were 12, 16, and 20 gauge and the heat damage introduced material changes in the wire insulation that made the originally flexible insulation brittle and darker in color. Results showed that extensional mode phase velocity increased for the samples that were exposed to heat for longer duration.

Solid-phase microextraction Ni-Ti fibers coated with functionalised silica particles immobilized in a sol-gel matrix.

PubMed

Azenha, Manuel; Ornelas, Mariana; Fernando Silva, A

2009-03-20

One of the possible approaches for the development of novel solid-phase microextraction (SPME) fibers is the physical deposition of porous materials onto a support using high-temperature epoxy glue. However, a major drawback arises from decomposition of epoxy glue at temperatures below 300 degrees C and instability in some organic solvents. This limitation motivated us to explore the possibility of replacing the epoxy glue with a sol-gel film, thermally more stable and resistant to organic solvents. We found that functionalised silica particles could be successfully attached to a robust Ni-Ti wire by using a UV-curable sol-gel film. The particles were found to be more important than the sol-gel layer during the microextraction process, as shown by competitive extraction trials and by the different extraction profiles observed with differently functionalised particles. If a quality control microscopic-check aiming at the rejection of fibers exhibiting unacceptably low particle load was conducted, acceptable (6-14%) reproducibility of preparation of C(18)-silica fibers was observed, and a strong indication of the durability of the fibers was also obtained. A cyclohexyldiol-silica fiber was used, as a simple example of applicability, for the successful determination of benzaldehyde, acetophenone and dimethylphenol at trace level in spiked tap water. Recoveries: 95-109%; limits of detection: 2-7 microg/L; no competition effects within the studied range (

Barley husk carbon as the fiber coating for the solid-phase microextraction of twelve pesticides in vegetables prior to gas chromatography-mass spectrometric detection.

PubMed

Liang, Weiqian; Wang, Juntao; Zang, Xiaohuan; Dong, Wenhuan; Wang, Chun; Wang, Zhi

2017-03-31

In this work, a barley husk biomaterial was successfully carbonized by hydrothermal method. The carbon had a high specific surface area and good stability. It was coated onto a stainless steel wire through sol-gel technique to prepare a solid-phase microextraction fiber for the extraction of trace levels of twelve pesticides (tsumacide, fenobucarb, indoxacarb, diethofencarb, thimet, terbufos, malathion, thiamethoxam, imidacloprid, buprofezin, acetamiprid, thiamethoxam) from vegetable samples prior to gas chromatography-mass spectrometric (GC-MS) detection. The main experimental parameters that could influence the extraction efficiency such as extraction time, extraction temperature, sample pH, sample salinity, stirring rate, desorption temperature and desorption time, were investigated. Under the optimized conditions, the linearity was observed in the range of 0.2-75.0μgkg -1 for tomato samples, and 0.3-60.0μgkg -1 for cucumber samples, with the correlation coefficients (r) ranging from 0.9959 to 0.9983. The limits of detection of the method were 0.01-0.05μgkg -1 for tomato samples, and 0.03-0.10μgkg -1 for cucumber samples. The recoveries of the analytes for the method from spiked samples were in the range of 76%-104%, and the precision, expressed as the relative standard deviations, was less than 12%. Copyright © 2017 Elsevier B.V. All rights reserved.

Doping of three-dimensional porous carbon nanotube-graphene-ionic liquid composite into polyaniline for the headspace solid-phase microextraction and gas chromatography determination of alcohols.

PubMed

Li, Lulu; Wu, Mian; Feng, Yingying; Zhao, Faqiong; Zeng, Baizhao

2016-12-15

In this work, ionic liquid (IL, i.e. 1-hydroxyethyl-3-methylimidazolium tetrafluoroborate), carboxyl multiwall carbon nanotubes (MWCNTs) and reduced graphene oxide (rGO) were used to prepare three-dimensional porous material (MWCNTs-rGO-IL) by one-step self-assembly, then it was co-electrodeposited with polyaniline (PANI) on stainless steel wires by cyclic voltammetry. The resulting coating (PANI-MWCNTs-rGO-IL) was characterized by using FT-IR and scanning electron microscopy etc, and it showed porous structure and had high thermal stability. Furthermore, it was found to be very suitable for the headspace solid-phase microextraction of alcohols (i.e. octanol, nonanol, geraniol, decanol, undecanol and dodecanol). By coupling with gas chromatography, wide linear ranges and low limits of detection (i.e. 2.2-28.3 ng L -1 ) were obtained for the alcohols. The coating also presented good repeatability and reproducibility; the relative standard deviations for intra-fiber and fiber-to-fiber were less than 5.6% (n = 5) and 7.0% (n = 5) respectively. In addition, the proposed method was successfully applied to the determination of alcohols in tea drinks, and the recoveries for standards added were 85.6-114%. Copyright © 2016 Elsevier B.V. All rights reserved.

Electrochemical fabrication of a novel polycarbazole coating for the headspace solid-phase microextraction and GC determination of some chlorobenzenes.

PubMed

Wang, Meng; Zhao, Fa-Qiong; Zeng, Bai-Zhao

2014-04-01

A novel polycarbazole coating was prepared by cyclic voltammetry on a platinum wire. The solution for electropolymerization contained N,N-dimethylformamide, propylene carbonate (v/v = 1:9), 0.10 M carbazole and 0.10 M tetrabutylammonium perchlorate; the cyclic scan potential range was 0.8-2.0 V (versus Ag/AgCl). The resulting polycarbazole coating showed a porous structure and had a large specific surface area. When it was used for the headspace solid-phase microextraction of chlorobenzenes (i.e. chlorobenzene, 2-chlorotoluene, 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,2,4-trichlorobenzene) followed by GC analysis, it presented excellent analytical performance. Under the optimized conditions the linear ranges were 0.25-250 μg/L with correlation coefficients >0.985, and the low detection limits were 15-61 ng/L (S/N = 3) for different chlorobenzenes. The RSDs were 2.4-4.9% for five successive measurements with a single fiber, and for fiber-to-fiber they were 6.3-13.1% (n = 5). Furthermore, the polycarbazole coating displayed good thermal stability (>350°C) and durability (more than 250 times). The proposed method was successfully applied to the extraction and determination of chlorobenzenes in waste water and lake water, and the recoveries for standards added were 86-114% for different analytes. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mesoporous carbon-zirconium oxide nanocomposite derived from carbonized metal organic framework: A coating for solid-phase microextraction.

PubMed

Saraji, Mohammad; Mehrafza, Narges

2016-08-19

In this paper, a mesoporous carbon-ZrO2 nanocomposite was fabricated on a stainless steel wire for the first time and used as the solid-phase microextraction coating. The fiber was synthesized with the direct carbonization of a Zr-based metal organic framework. With the utilization of the metal organic framework as the precursor, no additional carbon source was used for the synthesis of the mesoporous carbon-ZrO2 nanocomposite coating. The fiber was applied for the determination of BTEX compounds (benzene, toluene, ethylbenzene and m, p-xylenes) in different water samples prior to gas chromatography-flame ionization detection. Such important experimental factors as synthesis time and temperature, salt concentration, equilibrium and extraction time, extraction temperature, desorption time and desorption temperature were studied and optimized. Good linearity in the concentration range of 0.2-200μgL(-1) and detection limits in the range of 0.05-0.56μgL(-1) was achieved for BTEX compounds. The intra- and inter-day relative standard deviations were in the range of 3.5-4.8% and 4.9-6.7%, respectively. The prepared fiber showed high capability for the analysis of BTEX compounds in different water and wastewater samples with good relative recoveries in the range of 93-107%. Copyright © 2016 Elsevier B.V. All rights reserved.

Mobility of arsenic in a Bangladesh aquifer: Inferences from geochemical profiles, leaching data, and mineralogical characterization

NASA Astrophysics Data System (ADS)

Swartz, Christopher H.; Blute, Nicole Keon; Badruzzman, Borhan; Ali, Ashraf; Brabander, Daniel; Jay, Jenny; Besancon, James; Islam, Shafiqul; Hemond, Harold F.; Harvey, Charles F.

2004-11-01

Aquifer geochemistry was characterized at a field site in the Munshiganj district of Bangladesh where the groundwater is severely contaminated by As. Vertical profiles of aqueous and solid phase parameters were measured in a sandy deep aquifer (depth >150 m) below a thick confining clay (119 to 150 m), a sandy upper aquifer (3.5 to 119 m) above this confining layer, and a surficial clay layer (<3.5 m). In the deep aquifer and near the top of the upper aquifer, aqueous As levels are low (<10 μg/L), but aqueous As approaches a maximum of 640 μg/L at a depth of 30 to 40 m and falls to 58 μg/L near the base (107 m) of the upper aquifer. In contrast, solid phase As concentrations are uniformly low, rarely exceeding 2 μg/g in the two sandy aquifers and never exceeding 10 μg/g in the clay layers. Solid phase As is also similarly distributed among a variety of reservoirs in the deep and upper aquifer, including adsorbed As, As coprecipitated in solids leachable by mild acids and reductants, and As incorporated in silicates and other more recalcitrant phases. One notable difference among depths is that sorbed As loads, considered with respect to solid phase Fe extractable with 1 N HCl, 0.2 M oxalic acid, and a 0.5 M Ti(III)-citrate-EDTA solution, appear to be at capacity at depths where aqueous As is highest; this suggests that sorption limitations may, in part, explain the aqueous As depth profile at this site. Competition for sorption sites by silicate, phosphate, and carbonate oxyanions appear to sustain elevated aqueous As levels in the upper aquifer. Furthermore, geochemical profiles are consistent with the hypothesis that past or ongoing reductive dissolution of Fe(III) oxyhydroxides acts synergistically with competitive sorption to maintain elevated dissolved As levels in the upper aquifer. Microprobe data indicate substantial spatial comapping between As and Fe in both the upper and deep aquifer sediments, and microscopic observations reveal ubiquitous Fe coatings on most solid phases, including quartz, feldspars, and aluminosilicates. Extraction results and XRD analysis of density/magnetic separates suggest that these coatings may comprise predominantly Fe(II) and mixed valence Fe solids, although the presence of Fe(III) oxyhydroxides can not be ruled out. These data suggest As release may continue to be linked to dissolution processes targeting Fe, or Fe-rich, phases in these aquifers.

Surface topography, hardness, and frictional properties of GFRP for esthetic orthodontic wires.

PubMed

Inami, Toshihiro; Tanimoto, Yasuhiro; Yamaguchi, Masaru; Shibata, Yo; Nishiyama, Norihiro; Kasai, Kazutaka

2016-01-01

In our previous study, glass-fiber-reinforced plastics (GFRPs) made from polycarbonate and glass fiber for esthetic orthodontic wires were prepared by using pultrusion. The purpose of the present study was to investigate the surface topography, hardness, and frictional properties of GFRPs. To investigate how fiber diameter affects surface properties, GFRP round wires with a diameter of 0.45 mm (0.018 in.) were prepared incorporating either 13 μm (GFRP-13) or 7 μm (GFRP-7) glass fibers. As controls, stainless steel (SS), cobalt-chromium-nickel alloy, β-titanium (β-Ti) alloy, and nickel-titanium (Ni-Ti) alloy were also evaluated. Under scanning electron microscopy and scanning probe microscopy, the β-Ti samples exhibited greater surface roughness than the other metallic wires and the GFRP wires. The dynamic hardness and elastic modulus of GFRP wires obtained by the dynamic micro-indentation method were much lower than those of metallic wires (p < 0.05). Frictional forces against the polymeric composite brackets of GFRP-13 and GFRP-7 were 3.45 ± 0.49 and 3.60 ± 0.38 N, respectively; frictional forces against the ceramic brackets of GFRP-13 and GFRP-7 were 3.39 ± 0.58 and 3.87 ± 0.48 N, respectively. For both bracket types, frictional forces of GFRP wires and Ni-Ti wire were nearly half as low as those of SS, Co-Cr, and β-Ti wires. In conclusion, there was no significant difference in surface properties between GFRP-13 and GFRP-7; presumably because both share the same polycarbonate matrix. We expect that GFRP wires will deliver superior sliding mechanics with low frictional resistance between the wire and bracket during orthodontic treatment. © 2015 Wiley Periodicals, Inc.

Multiwire Thermocouples in Reversing Flow

NASA Technical Reports Server (NTRS)

Forney, L. J.; Fralick, G. C.

1995-01-01

Measurements are recorded for multiwire thermocouples consisting of either two or three wires of unequal diameters. Signals from the multiwire probe are recorded for a reversing gas flow with both a periodic temperature and time constant fluctuation. It is demonstrated that the reconstructed signal from the multiwire thermocouple requires no compensation provided omega/omega(sub 1) less than 2.3 for two wires or omega/omega(sub 1) less than 3.6 for three wires where omega(sub 1) (= 2(pi)f) is the natural frequency of the smaller wire based on the maximum gas velocity. The latter results were possible provided Fourier transformed data from the wires were used and knowledge of the gas velocity phase angle was available.

Longitudinal magnet forces?

NASA Astrophysics Data System (ADS)

Graneau, P.

1984-03-01

The Ampere electrodynamics of metallic conductors and experiments supporting it predict that the interaction of a current-carrying wire with its own magnetic field should produce longitudinal mechanical forces in the conductor, existing in addition to the transverse Lorentz forces. The longitudinal forces should stretch the conductor and have been referred to as Ampere tension. In 1964 it was discovered that a current pulse would break a straight copper wire into many fragments without visible melting. A metallurgical examination of the pieces confirmed that the metal parted in the solid state. The same observation has now been made with aluminum wires. In the latest experiments the wire was bent into a semicircle and arc-connected to a capacitor discharge circuit. The arc connections ruled out rupture by Lorentz hoop tension and indicated the longitudinal forces may also arise in circular magnet windings. Explanations of wire fragmentation by thermal shock, longitudinal stress waves, Lorentz pinch-off, bending stresses, and material defects have been considered and found unconvincing. Computed Ampere tensions would be sufficient to fracture hot wires. The Ampere tension would double the hoop tension normally expected in dipole magnets. This should be borne in mind in the design of large dipole magnets contemplated for MHD power generators and railgun accelerators.

Strengthening of Aluminum Wires Treated with A206/Alumina Nanocomposites.

PubMed

Florián-Algarín, David; Marrero, Raúl; Li, Xiaochun; Choi, Hongseok; Suárez, Oscar Marcelo

2018-03-10

This study sought to characterize aluminum nanocomposite wires that were fabricated through a cold-rolling process, having potential applications in TIG (tungsten inert gas) welding of aluminum. A206 (Al-4.5Cu-0.25Mg) master nanocomposites with 5 wt % γAl₂O₃ nanoparticles were first manufactured through a hybrid process combining semi-solid mixing and ultrasonic processing. A206/1 wt % γAl₂O₃ nanocomposites were fabricated by diluting the prepared master nanocomposites with a monolithic A206 alloy, which was then added to a pure aluminum melt. The fabricated Al-γAl₂O₃ nanocomposite billet was cold-rolled to produce an Al nanocomposite wire with a 1 mm diameter and a transverse area reduction of 96%. Containing different levels of nanocomposites, the fabricated samples were mechanically and electrically characterized. The results demonstrate a significantly higher strength of the aluminum wires with the nanocomposite addition. Further, the addition of alumina nanoparticles affected the wires' electrical conductivity compared with that of pure aluminum and aluminum-copper alloys. The overall properties of the new material demonstrate that these wires could be an appealing alternative for fillers intended for aluminum welding.

Gas-Phase Synthesis of Gold- and Silica-Coated Nanoparticles

NASA Astrophysics Data System (ADS)

Boies, Adam Meyer

2011-12-01

Composite nanoparticles consisting of separate core-shell materials are of interest for a variety of biomedical and industrial applications. By combining different materials at the nanoscale, particles can exhibit enhanced or multi-functional behavior such as plasmon resonance combined with superparamagnetism. Gas-phase nanoparticle synthesis processes are promising because they can continuously produce particles with high mass-yield rates. In this dissertation, new methods are investigated for producing gas-phase coatings of nanoparticles in an "assembly-line" fashion. Separate processes are developed to create coatings from silica and gold that can be used with a variety of core-particle chemistries. A photoinduced chemical vapor deposition (photo-CVD) method is used to produce silica coatings from tetraethyl orthosilicate (TEOS) on the surface of nanoparticles (diameter ˜5--70 nm). Tandem differential mobility analysis (TDMA) of the process demonstrates that particle coatings can be produced with controllable thicknesses (˜1--10 nm) by varying system parameters such as precursor flow rate. Electron microscopy and infrared spectroscopy confirm that the photo-CVD films uniformly coat the particles and that the coatings are silica. In order to describe the coating process a chemical mechanism is proposed that includes gas-phase, surface and photochemical reactions. A chemical kinetics model of the mechanism indicates that photo-CVD coating proceeds primarily through the photodecomposition of TEOS which removes ethyl groups, thus creating activated TEOS species. The activated TEOS then adsorbs onto the surface of the particle where a series of subsequent reactions remove the remaining ethyl groups to produce a silica film with an open site for further attachment. The model results show good agreement with the experimentally measured coating trends, where increased TEOS flow increases coating thickness and increased nitrogen flow decreases coating thickness. Gold decoration of nanoparticles is accomplished by evaporation of solid gold in the presence of an aerosol flow. A hot-wire generation method is developed where gold particles are produced from a composite gold-platinum wire. Investigations of the hot-wire generator show that it can produce particles with a range of sizes and that more uniform, non-agglomerated particles are produced when using smaller diameter tubes where gas velocities across the wire are higher and recirculation zones are diminished. When gold is evaporated in the presence of silica nanoparticles, the silica aerosol is decorated by gold through either homogeneous gold nucleation and subsequent scavenging by the silica nanoparticles, or by heterogeneous nucleation on the silica surface in which the gold "balls up" due to the high surface tension of gold on silica. In both cases the resulting particles exhibit a plasmon absorbance resonance typical of gold nanoparticles (lambda˜550 nm). Finally, the silica coating and gold decoration processes are combined with a thermal plasma technique for synthesizing iron-oxide to produce tri-layer nanoparticles.

Disorderly Light.

ERIC Educational Resources Information Center

Peterson, Ivars

1991-01-01

The relationship between theories about electrical conductivity in microscopic wires and laser speckle patterns is described. Practical applications of laser speckle patterns are included. Wave ideas are being used to describe and predict novel phenomena in disordered solids. (KR)

9 CFR 3.3 - Sheltered housing facilities.

Code of Federal Regulations, 2012 CFR

2012-01-01

... attending veterinarian. Dry bedding, solid resting boards, or other methods of conserving body heat must be... wire, wood, metal, or concrete; and (iii) All walls, boxes, houses, dens, and other surfaces in contact...

9 CFR 3.3 - Sheltered housing facilities.

Code of Federal Regulations, 2013 CFR

2013-01-01

... attending veterinarian. Dry bedding, solid resting boards, or other methods of conserving body heat must be... wire, wood, metal, or concrete; and (iii) All walls, boxes, houses, dens, and other surfaces in contact...

9 CFR 3.3 - Sheltered housing facilities.

Code of Federal Regulations, 2014 CFR

2014-01-01

... attending veterinarian. Dry bedding, solid resting boards, or other methods of conserving body heat must be... wire, wood, metal, or concrete; and (iii) All walls, boxes, houses, dens, and other surfaces in contact...

5' modification of duplex DNA with a ruthenium electron donor-acceptor pair using solid-phase DNA synthesis

NASA Technical Reports Server (NTRS)

Frank, Natia L.; Meade, Thomas J.

2003-01-01

Incorporation of metalated nucleosides into DNA through covalent modification is crucial to measurement of thermal electron-transfer rates and the dependence of these rates with structure, distance, and position. Here, we report the first synthesis of an electron donor-acceptor pair of 5' metallonucleosides and their subsequent incorporation into oligonucleotides using solid-phase DNA synthesis techniques. Large-scale syntheses of metal-containing oligonucleotides are achieved using 5' modified phosporamidites containing [Ru(acac)(2)(IMPy)](2+) (acac is acetylacetonato; IMPy is 2'-iminomethylpyridyl-2'-deoxyuridine) (3) and [Ru(bpy)(2)(IMPy)](2+) (bpy is 2,2'-bipyridine; IMPy is 2'-iminomethylpyridyl-2'-deoxyuridine) (4). Duplexes formed with the metal-containing oligonucleotides exhibit thermal stability comparable to the corresponding unmetalated duplexes (T(m) of modified duplex = 49 degrees C vs T(m) of unmodified duplex = 47 degrees C). Electrochemical (3, E(1/2) = -0.04 V vs NHE; 4, E(1/2) = 1.12 V vs NHE), absorption (3, lambda(max) = 568, 369 nm; 4, lambda(max) = 480 nm), and emission (4, lambda(max) = 720 nm, tau = 55 ns, Phi = 1.2 x 10(-)(4)) data for the ruthenium-modified nucleosides and oligonucleotides indicate that incorporation into an oligonucleotide does not perturb the electronic properties of the ruthenium complex or the DNA significantly. In addition, the absence of any change in the emission properties upon metalated duplex formation suggests that the [Ru(bpy)(2)(IMPy)](2+)[Ru(acac)(2)(IMPy)](2+) pair will provide a valuable probe for DNA-mediated electron-transfer studies.

Nondestructive x-ray Scattering Characterization of High Temperature Superconducting Wires

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thurston, T R

The purpose of this CRADA was to characterize the structural properties of the superconductor material within the wires in order to determine which processing procedures produce the best superconductor texture and phase development, and hence the best ultimate current carrying capacity.

YBCO Coated Conductor with an Integrated Optical Fiber Sensor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sathyamurthy, Srivatsan; Rupich, Marty; Schwartz, Justin

2016-03-31

The primary objectives of the Phase I Project was to develop a proof-of-principle for a concept of integrating an optical fiber sensor into the laminated 2G wire, there by producing a functionalized 2G wire with self-monitoring capabilities

Equivalence of electronic and mechanical stresses in structural phase stabilization: A case study of indium wires on Si(111)

NASA Astrophysics Data System (ADS)

Kim, Sun-Woo; Kim, Hyun-Jung; Ming, Fangfei; Jia, Yu; Zeng, Changgan; Cho, Jun-Hyung; Zhang, Zhenyu

2015-05-01

It was recently proposed that the stress state of a material can also be altered via electron or hole doping, a concept termed electronic stress (ES), which is different from the traditional mechanical stress (MS) due to lattice contraction or expansion. Here we demonstrate the equivalence of ES and MS in structural stabilization, using In wires on Si(111) as a prototypical example. Our systematic density-functional theory calculations reveal that, first, for the same degrees of carrier doping into the In wires, the ES of the high-temperature metallic 4 ×1 structure is only slightly compressive, while that of the low-temperature insulating 8 ×2 structure is much larger and highly anisotropic. As a consequence, the intrinsic energy difference between the two phases is significantly reduced towards electronically phase-separated ground states. Our calculations further demonstrate quantitatively that such intriguing phase tunabilities can be achieved equivalently via lattice-contraction induced MS in the absence of charge doping. We also validate the equivalence through our detailed scanning tunneling microscopy experiments. The present findings have important implications for understanding the underlying driving forces involved in various phase transitions of simple and complex systems alike.

Recent advances in theoretical and numerical studies of wire array Z-pinch in the IAPCM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ding, Ning, E-mail: ding-ning@iapcm.ac.cn; Zhang, Yang, E-mail: ding-ning@iapcm.ac.cn; Xiao, Delong, E-mail: ding-ning@iapcm.ac.cn

2014-12-15

Fast Z-pinch has produced the most powerful X-ray radiation source in laboratory and also shows the possibility to drive inertial confinement fusion (ICF). Recent advances in wire-array Z-pinch researches at the Institute of Applied Physics and Computational Mathematics are presented in this paper. A typical wire array Z-pinch process has three phases: wire plasma formation and ablation, implosion and the MRT instability development, stagnation and radiation. A mass injection model with azimuthal modulation coefficient is used to describe the wire initiation, and the dynamics of ablated plasmas of wire-array Z-pinches in (r, θ) geometry is numerically studied. In the implosionmore » phase, a two-dimensional(r, z) three temperature radiation MHD code MARED has been developed to investigate the development of the Magneto-Rayleigh-Taylor(MRT) instability. We also analyze the implosion modes of nested wire-array and find that the inner wire-array is hardly affected before the impaction of the outer wire-array. While the plasma accelerated to high speed in the implosion stage stagnates on the axis, abundant x-ray radiation is produced. The energy spectrum of the radiation and the production mechanism are investigated. The computational x-ray pulse shows a reasonable agreement with the experimental result. We also suggest that using alloyed wire-arrays can increase multi-keV K-shell yield by decreasing the opacity of K-shell lines. In addition, we use a detailed circuit model to study the energy coupling between the generator and the Z-pinch implosion. Recently, we are concentrating on the problems of Z-pinch driven ICF, such as dynamic hohlraum and capsule implosions. Our numerical investigations on the interaction of wire-array Z-pinches on foam convertors show qualitative agreements with experimental results on the “Qiangguang I” facility. An integrated two-dimensional simulation of dynamic hohlraum driven capsule implosion provides us the physical insights of wire-array plasma acceleration, shock generation and production, hohlraum formation, radiation ablation and fuel compression.« less

Effect of three-body interactions on the zero-temperature equation of state of HCP solid 4He

NASA Astrophysics Data System (ADS)

Barnes, Ashleigh L.; Hinde, Robert J.

2017-03-01

Previous studies have pointed to the importance of three-body interactions in high density 4He solids. However the computational cost often makes it unfeasible to incorporate these interactions into the simulation of large systems. We report the implementation and evaluation of a computationally efficient perturbative treatment of three-body interactions in hexagonal close packed solid 4He utilizing the recently developed nonadditive three-body potential of Cencek et al. This study represents the first application of the Cencek three-body potential to condensed phase 4He systems. Ground state energies from quantum Monte Carlo simulations, with either fully incorporated or perturbatively treated three-body interactions, are calculated in systems with molar volumes ranging from 21.3 cm3/mol down to 2.5 cm3/mol. These energies are used to derive the zero-temperature equation of state for comparison against existing experimental and theoretical data. The equations of state derived from both perturbative and fully incorporated three-body interactions are found to be in very good agreement with one another, and reproduce the experimental pressure-volume data with significantly better accuracy than is obtained when only two-body interactions are considered. At molar volumes below approximately 4.0 cm3/mol, neither two-body nor three-body equations of state are able to accurately reproduce the experimental pressure-volume data, suggesting that below this molar volume four-body and higher many-body interactions are becoming important.

Synthesis of Ti3AuC2, Ti3Au2C2 and Ti3IrC2 by noble metal substitution reaction in Ti3SiC2 for high-temperature-stable Ohmic contacts to SiC

NASA Astrophysics Data System (ADS)

Fashandi, Hossein; Dahlqvist, Martin; Lu, Jun; Palisaitis, Justinas; Simak, Sergei I.; Abrikosov, Igor A.; Rosen, Johanna; Hultman, Lars; Andersson, Mike; Lloyd Spetz, Anita; Eklund, Per

2017-08-01

The large class of layered ceramics encompasses both van der Waals (vdW) and non-vdW solids. While intercalation of noble metals in vdW solids is known, formation of compounds by incorporation of noble-metal layers in non-vdW layered solids is largely unexplored. Here, we show formation of Ti3AuC2 and Ti3Au2C2 phases with up to 31% lattice swelling by a substitutional solid-state reaction of Au into Ti3SiC2 single-crystal thin films with simultaneous out-diffusion of Si. Ti3IrC2 is subsequently produced by a substitution reaction of Ir for Au in Ti3Au2C2. These phases form Ohmic electrical contacts to SiC and remain stable after 1,000 h of ageing at 600 °C in air. The present results, by combined analytical electron microscopy and ab initio calculations, open avenues for processing of noble-metal-containing layered ceramics that have not been synthesized from elemental sources, along with tunable properties such as stable electrical contacts for high-temperature power electronics or gas sensors.

Medial malleolar fractures: a biomechanical study of fixation techniques.

PubMed

Fowler, T Ty; Pugh, Kevin J; Litsky, Alan S; Taylor, Benjamin C; French, Bruce G

2011-08-08

Fracture fixation of the medial malleolus in rotationally unstable ankle fractures typically results in healing with current fixation methods. However, when failure occurs, pullout of the screws from tension, compression, and rotational forces is predictable. We sought to biomechanically test a relatively new technique of bicortical screw fixation for medial malleoli fractures. Also, the AO group recommends tension-band fixation of small avulsion type fractures of the medial malleolus that are unacceptable for screw fixation. A well-documented complication of this technique is prominent symptomatic implants and secondary surgery for implant removal. Replacing stainless steel 18-gauge wire with FiberWire suture could theoretically decrease symptomatic implants. Therefore, a second goal was to biomechanically compare these 2 tension-band constructs. Using a tibial Sawbones model, 2 bicortical screws were compared with 2 unicortical cancellous screws on a servohydraulic test frame in offset axial, transverse, and tension loading. Second, tension-band fixation using stainless steel wire was compared with FiberWire under tensile loads. Bicortical screw fixation was statistically the stiffest construct under tension loading conditions compared to unicortical screw fixation and tension-band techniques with FiberWire or stainless steel wire. In fact, unicortical screw fixation had only 10% of the stiffness as demonstrated in the bicortical technique. In a direct comparison, tension-band fixation using stainless steel wire was statistically stiffer than the FiberWire construct. Copyright 2011, SLACK Incorporated.

Scavenging of acidic gases (HCOOH, CH3COOH, HNO3, HCl, and SO2) and ammonia in mixed liquid-solid water clouds at the Puy de Do‸me mountain (France)

NASA Astrophysics Data System (ADS)

Voisin, Didier; Legrand, Michel; Chaumerliac, Nadine

2000-03-01

In order to study scavenging processes of chemical species in mixed phase clouds, in-cloud field measurements were conducted in December 1997 at the Puy de Dôme mountain (center of France, 1465 m above sea level). Soluble species including NH+4, Cl-;, NO3-3, SO-4, HCOO-, CH3COO-, and C2O-4 present in the different phases (supercooled water droplets, rimed snowflakes, interstitial gases, and aerosols) of cold clouds have been investigated. Conducted in parallel to microphysical studies of clouds (liquid water and ice contents, and size distribution of hydrometeors), these chemical investigations allow us to examine the partitioning of strong (HNO3 and HCl) and weak (SO2, HCOOH, and CH3COOH) acids as well as ammonia between interstitial air and the condensed phases (liquid and solid water particles) in mixed clouds present during winter at midlatitude regions. From that, we discuss the processes by which these key atmospheric species are taken up from the gas phase by the condensed phases (liquid and ice) in these cold clouds. We examine several factors which are of importance in driving the final composition of cloud ice. They include the partitioning of species between gaseous and supercooled liquid phases, the amount of rimed ice collected by snowflakes, and the retention of gas during shock freezing of supercooled droplets onto ice particles. Strong acids (HCl and HNO3) as well as NH3, being sufficiently soluble in water, are mainly partitioned into supercooled water droplets. Furthermore, being subsaturated in liquid droplets, these species are well retained in rimed ice. For these species, riming is found to be the main process driving the final composition of snowflakes, direct incorporation from the gas phase during growth of snowflakes remaining insignificant because of low concentrations in the gas phase. For light carboxylic acids the riming process mainly determines the composition of the snowflakes, but an additional significant contribution by gas incorporation during the growth of snowflakes cannot be excluded. SO2 is also present at significant levels in the interstitial air and is poorly retained in ice during riming of supercooled water droplets. However, hydroxymethanesulfonate (HMSA) was likely present in supercooled liquid droplets, making it difficult to evaluate by which mechanism S(IV) (i.e., HMSA plus SO2) has been incorporated into snowflakes.

Optical phonon effect in quasi-one-dimensional semiconductor quantum wires: Band-gap renormalization

NASA Astrophysics Data System (ADS)

Dan, Nguyen Trung; Bechstedt, F.

1996-02-01

We present theoretical studies of dynamical screening in quasi-one-dimensional semiconductor quantum wires including electron-electron and electron-LO-phonon interactions. Within the random-phase approximation we obtain analytical expressions for screened interaction potentials. These expressions can be used to calculate the band-gap renormalization of quantum wires, which depends on the free-carrier density and temperature. We find that the optical phonon interaction effect plays a significant role in band-gap renormalization of quantum wires. The numerical results are compared with some recent experiment measurements as well as available theories.

Texturing of high T(sub c) superconducting polycrystalline fibers/wires by laser-driven directional solidification in an thermal gradient

NASA Technical Reports Server (NTRS)

Varshney, Usha; Eichelberger, B. Davis, III

1995-01-01

This paper summarizes the technique of laser-driven directional solidification in a controlled thermal gradient of yttria stabilized zirconia core coated Y-Ba-Cu-O materials to produce textured high T(sub c) superconducting polycrystalline fibers/wires with improved critical current densities in the extended range of magnetic fields at temperatures greater than 77 K. The approach involves laser heating to minimize phase segregation by heating very rapidly through the two-phase incongruent melt region to the single phase melt region and directionally solidifying in a controlled thermal gradient to achieve highly textured grains in the fiber axis direction. The technique offers a higher grain growth rate and a lower thermal budget compared with a conventional thermal gradient and is amenable as a continuous process for improving the J(sub c) of high T(sub c) superconducting polycrystalline fibers/wires. The technique has the advantage of suppressing weak-link behavior by orientation of crystals, formation of dense structures with enhanced connectivity, formation of fewer and cleaner grain boundaries, and minimization of phase segregation in the incongruent melt region.

A unified heteronuclear decoupling strategy for magic-angle-spinning solid-state NMR spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Equbal, Asif; Bjerring, Morten; Nielsen, Niels Chr., E-mail: madhu@tifr.res.in, E-mail: ncn@inano.au.dk

2015-05-14

A unified strategy of two-pulse based heteronuclear decoupling for solid-state magic-angle spinning nuclear magnetic resonance is presented. The analysis presented here shows that different decoupling sequences like two-pulse phase-modulation (TPPM), X-inverse-X (XiX), and finite pulse refocused continuous wave (rCW{sup A}) are basically specific solutions of a more generalized decoupling scheme which incorporates the concept of time-modulation along with phase-modulation. A plethora of other good decoupling conditions apart from the standard, TPPM, XiX, and rCW{sup A} decoupling conditions are available from the unified decoupling approach. The importance of combined time- and phase-modulation in order to achieve the best decoupling conditions ismore » delineated. The consequences of different indirect dipolar interactions arising from cross terms comprising of heteronuclear and homonuclear dipolar coupling terms and also those between heteronuclear dipolar coupling and chemical-shift anisotropy terms are presented in order to unfold the effects of anisotropic interactions under different decoupling conditions. Extensive numerical simulation results are corroborated with experiments on standard amino acids.« less

Magnetic hysteresis in small-grained CoxPd1-x nanowire arrays

NASA Astrophysics Data System (ADS)

Viqueira, M. S.; Pozo-López, G.; Urreta, S. E.; Condó, A. M.; Cornejo, D. R.; Fabietti, L. M.

2015-11-01

Co-Pd nanowires with small grain size are fabricated by AC electrodeposition into hexagonally ordered alumina pores, 20-35 nm in diameter and about 1 μm long. The effects of the alloy composition, the nanowire diameter and the grain size on the hysteresis properties are considered. X-ray diffraction indicates that the nanowires are single phase, a fcc Co-Pd solid solution; electron microscopy results show that they are polycrystalline, with randomly oriented grains (7-12 nm), smaller than the wire diameter. Nanowire arrays are ferromagnetic, with an easy magnetization axis parallel to the nanowire long axis. Both, the coercive field and the loop squareness monotonously increase with the Co content and with the grain size, but no clear correlation with the wire diameter is found. The Co and Co-rich nanowire arrays exhibit coercive fields and reduced remanence values quite insensitive to temperature in the range 4 K-300 K; on the contrary, in Pd-rich nanowires both magnitudes are smaller and they largely increase during cooling below 100 K. These behaviors are systematized by considering the strong dependences displayed by the magneto-crystalline anisotropy and the saturation magnetostriction on composition and temperature. At low temperatures the effective anisotropy value and the domain-wall width to grain size ratio drastically change, promoting less cooperative and harder nucleation modes.

BAE Systems Radiation Hardened SpaceWire ASIC and Roadmap

NASA Technical Reports Server (NTRS)

Berger, Richard; Milliser, Myrna; Kapcio, Paul; Stanley, Dan; Moser, David; Koehler, Jennifer; Rakow, Glenn; Schnurr, Richard

2006-01-01

An Application Specific Integrated Circuit (ASIC) that implements the SpaceWire protocol has been developed in a radiation hardened 0.25 micron CMOS, technology. This effort began in March 2003 as a joint development between the NASA Goddard Space Flight Center (GSFC) and BAE Systems. The BAE Systems SpaceWire ASlC is comprised entirely of reusable core elements, many of which are already flight-proven. It incorporates a 4-port SpaceWire router with two local ports, dual PC1 bus interfaces, a microcontroller, 32KB of internal memory, -and a memory controller for additional external memory use. The SpaceWire ASlC is planned for use on both the Geostationary Operational Environmental Satellites (GOES)-R and the Lunar Reconnaissance Orbiter (LRO). Engineering parts have already been delivered to both programs. This paper discusses the SpaceWire protocol and those elements of it that have been built into the current SpaceWire reusable core. There are features within the core that go beyond the current standard that can be enabled or disabled by the user and these will be described. The adaptation of SpaceWire to BAE Systems' On Chip Bus (OCB) for compatibility with the other reusable cores will be discussed. Optional configurations within user systems will be shown. The physical imp!ementation of the design will be described and test results from the hardware will be discussed. Finally, the BAE Systems roadmap for SpaceWire developments will be discussed, including some products already in design as well as longer term plans.

Detoxification and immobilization of chromite ore processing residue in spinel-based glass-ceramic.

PubMed

Liao, Chang-Zhong; Tang, Yuanyuan; Lee, Po-Heng; Liu, Chengshuai; Shih, Kaimin; Li, Fangbai

2017-01-05

A promising strategy for the detoxification and immobilization of chromite ore processing residue (COPR) in a spinel-based glass-ceramic matrix is reported in this study. In the search for a more chemically durable matrix for COPR, the most critical crystalline phase for Cr immobilization was found to be a spinel solid solution with a chemical composition of MgCr 1.32 Fe 0.19 Al 0.49 O 4 . Using Rietveld quantitative X-ray diffraction analysis, we identified this final product is with the phases of spinel (3.5wt.%), diopside (5.2wt.%), and some amorphous contents (91.2wt.%). The partitioning ratio of Cr reveals that about 77% of the Cr was incorporated into the more chemically durable spinel phase. The results of Cr K-edge X-ray absorption near-edge spectroscopy show that no Cr(VI) was observed after conversion of COPR into a glass-ceramic, which indicates successful detoxification of Cr(VI) into Cr(III) in the COPR-incorporated glass-ceramic. The leaching performances of Cr 2 O 3 and COPR-incorporated glass-ceramic were compared with a prolonged acid-leaching test, and the results demonstrate the superiority of the COPR-incorporated glass-ceramic matrix in the immobilization of Cr. The overall results suggest that the use of affordable additives has potential in more reliably immobilizing COPR with a spinel-based glass-ceramic for safer disposal of this hazardous waste. Copyright © 2016 Elsevier B.V. All rights reserved.

Antenna coupled photonic wire lasers

DOE PAGES

Kao, Tsung-Kao; Cai, Xiaowei; Lee, Alan W. M.; ...

2015-06-22

Slope efficiency (SE) is an important performance metric for lasers. In conventional semiconductor lasers, SE can be optimized by careful designs of the facet (or the modulation for DFB lasers) dimension and surface. However, photonic wire lasers intrinsically suffer low SE due to their deep sub-wavelength emitting facets. Inspired by microwave engineering techniques, we show a novel method to extract power from wire lasers using monolithically integrated antennas. These integrated antennas significantly increase the effective radiation area, and consequently enhance the power extraction efficiency. When applied to wire lasers at THz frequency, we achieved the highest single-side slope efficiency (~450more » mW/A) in pulsed mode for DFB lasers at 4 THz and a ~4x increase in output power at 3 THz compared with a similar structure without antennas. This work demonstrates the versatility of incorporating microwave engineering techniques into laser designs, enabling significant performance enhancements.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rossi, Adriana; et al.

Long-range beam-beam (LRBB) interactions can be a source of emittance growth and beam losses in the LHC during physics and will become even more relevant with the smaller '* and higher bunch intensities foreseen for the High Luminosity LHC upgrade (HL-LHC), in particular if operated without crab cavities. Both beam losses and emittance growth could be mitigated by compensat-ing the non-linear LRBB kick with a correctly placed current carrying wire. Such a compensation scheme is currently being studied in the LHC through a demonstration test using current-bearing wires embedded into col-limator jaws, installed either side of the high luminosity interactionmore » regions. For HL-LHC two options are considered, a current-bearing wire as for the demonstrator, or electron lenses, as the ideal distance between the particle beam and compensating current may be too small to allow the use of solid materials. This paper reports on the ongoing activities for both options, covering the progress of the wire-in-jaw collimators, the foreseen LRBB experiments at the LHC, and first considerations for the design of the electron lenses to ultimately replace material wires for HL-LHC.« less

Fundamental phenomena on fuel decomposition and boundary-layer combustion processes with applications to hybrid rocket motors

NASA Technical Reports Server (NTRS)

Kuo, Kenneth K.; Lu, Yeu-Cherng; Chiaverini, Martin J.; Harting, George C.; Johnson, David K.; Serin, Nadir

1995-01-01

The experimental study on the fundamental processes involved in fuel decomposition and boundary-layer combustion in hybrid rocket motors is continuously being conducted at the High Pressure Combustion Laboratory of The Pennsylvania State University. This research will provide a useful engineering technology base in the development of hybrid rocket motors as well as a fundamental understanding of the complex processes involved in hybrid propulsion. A high-pressure, 2-D slab motor has been designed, manufactured, and utilized for conducting seven test firings using HTPB fuel processed at PSU. A total of 20 fuel slabs have been received from the Mcdonnell Douglas Aerospace Corporation. Ten of these fuel slabs contain an array of fine-wire thermocouples for measuring solid fuel surface and subsurface temperatures. Diagnostic instrumentation used in the test include high-frequency pressure transducers for measuring static and dynamic motor pressures and fine-wire thermocouples for measuring solid fuel surface and subsurface temperatures. The ultrasonic pulse-echo technique as well as a real-time x-ray radiography system have been used to obtain independent measurements of instantaneous solid fuel regression rates.

Fundamental phenomena on fuel decomposition and boundary-layer combustion processes with applications to hybrid rocket motors

NASA Astrophysics Data System (ADS)

Kuo, Kenneth K.; Lu, Yeu-Cherng; Chiaverini, Martin J.; Harting, George C.; Johnson, David K.; Serin, Nadir

The experimental study on the fundamental processes involved in fuel decomposition and boundary-layer combustion in hybrid rocket motors is continuously being conducted at the High Pressure Combustion Laboratory of The Pennsylvania State University. This research will provide a useful engineering technology base in the development of hybrid rocket motors as well as a fundamental understanding of the complex processes involved in hybrid propulsion. A high-pressure, 2-D slab motor has been designed, manufactured, and utilized for conducting seven test firings using HTPB fuel processed at PSU. A total of 20 fuel slabs have been received from the Mcdonnell Douglas Aerospace Corporation. Ten of these fuel slabs contain an array of fine-wire thermocouples for measuring solid fuel surface and subsurface temperatures. Diagnostic instrumentation used in the test include high-frequency pressure transducers for measuring static and dynamic motor pressures and fine-wire thermocouples for measuring solid fuel surface and subsurface temperatures. The ultrasonic pulse-echo technique as well as a real-time x-ray radiography system have been used to obtain independent measurements of instantaneous solid fuel regression rates.

Study of thermomechanical treatment on mechanical-induced phase transformation of NiTi and TiNiCu wires.

PubMed

Seyyed Aghamiri, S M; Nili Ahmadabadi, M; Shahmir, H; Naghdi, F; Raygan, Sh

2013-05-01

The nickel-titanium shape memory alloys have been used in orthodontic application due to their unique properties like superelasticity and biocompatibility. The phase transformation behavior of these alloys can be changed by alloying elements and thermomechanical processing conditions. In this study, two types of NiTi and TiNiCu wires of 0.4mm diameter were produced via thermomechanical treatments with final step of 20% cold drawing followed by annealing at different temperatures of 300 and 400 °C for varying times of 10, 30 and 60 min. The processed wires were characterized by oral cavity configuration three point bending (OCTPB) test at 37 °C to specify the mechanical transformation features. Also, differential scanning calorimetry (DSC) was used to analyze the thermal transformation temperatures of selected wires. The results showed the thermomechanical treatment at 300 °C for 30 min was the suitable process in terms of superelasticity and transformation temperatures for orthodontic application. Copyright © 2013 Elsevier Ltd. All rights reserved.

Ionization Electron Signal Processing in Single Phase LArTPCs I. Algorithm Description and Quantitative Evaluation with MicroBooNE Simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adams, C.; et al.

We describe the concept and procedure of drifted-charge extraction developed in the MicroBooNE experiment, a single-phase liquid argon time projection chamber (LArTPC). This technique converts the raw digitized TPC waveform to the number of ionization electrons passing through a wire plane at a given time. A robust recovery of the number of ionization electrons from both induction and collection anode wire planes will augment the 3D reconstruction, and is particularly important for tomographic reconstruction algorithms. A number of building blocks of the overall procedure are described. The performance of the signal processing is quantitatively evaluated by comparing extracted charge withmore » the true charge through a detailed TPC detector simulation taking into account position-dependent induced current inside a single wire region and across multiple wires. Some areas for further improvement of the performance of the charge extraction procedure are also discussed.« less

Crystal growth of argyrodite-type phases Cu 8-xGeS 6-xI x and Cu 8-xGeSe 6-xI x (0⩽ x⩽0.8)

NASA Astrophysics Data System (ADS)

Tomm, Yvonne; Schorr, Susan; Fiechter, Sebastian

2008-04-01

The growth of single crystalline argyrodites of type Cu 8-xGeX 6-xY x ( X=S, Se; Y=I) is reported. These materials undergo solid-solid phase transitions at temperatures ranging from 30 to 90 °C. In the high temperature phase, Cu 8GeS 6 crystallizes in the cubic space group F4¯3m. In the low temperature phase, the compound is present in the orthorhombic space group Pmn2 1. Cu 8GeSe 6 appears exclusively in the hexagonal space groups P6 3mc or P6 3cm, respectively. Single crystals of these argyrodites were obtained by chemical vapor transport in a temperature gradient Δ T=980-950 and Δ T=700-620 °C for sulfides and selenides, respectively. As a result of the growth process, the high temperature phase remains stable even at ambient temperature by incorporation of the transport agent iodine during the growth process. As determined by energy dispersive X-ray analysis (EDAX), the composition of the sulfide crystals grown ranges from Cu 8GeS 6 to Cu 7.16GeS 5.16I 0.84. The selenide crystallizes as Cu 7.69GeSe 5.69I 0.31. In contrast, the solid state reaction of the elements Cu, Ge and X produces a material in the low temperature modification with an ideal composition of Cu 8GeX 6.

Tracing bacterial metabolism using multi-nuclear (1H, 2H, and 13C) Solid State NMR: Realizing an Idea Initiated by James Scott

NASA Astrophysics Data System (ADS)

Cody, G.; Fogel, M. L.; Jin, K.; Griffen, P.; Steele, A.; Wang, Y.

2011-12-01

Approximately 6 years ago, while at the Geophysical Laboratory, James Scott became interested in the application of Solid State Nuclear Magnetic Resonance Spectroscopy to study bacterial metabolism. As often happens, other experiments intervened and the NMR experiments were not pursued. We have revisited Jame's question and find that using a multi-nuclear approach (1H, 2H, and 13C Solid State NMR) on laboratory cell culture has some distinct advantages. Our experiments involved batch cultures of E. coli (MG1655) harvested at stationary phase. In all experiments the growth medium consisted of MOPS medium for enterobacteria, where the substrate is glucose. In one set of experiments, 10 % of the water was D2O; in another 10 % of the glucose was per-deuterated. The control experiment used both water and glucose at natural isotopic abundance. A kill control of dead E. coli immersed in pure D2O for an extended period exhibited no deuterium incorporation. In both deuterium enriched experiments, considerable incorporation of deuterium into E. coli's biomolecular constituents was detected via 2H Solid State NMR. In the case of the D2O enriched experiment, 58 % of the incorporated deuterium is observed in a sharp peak at a frequency of 0.31 ppm, consistent with D incorporation in the cell membrane lipids, the remainder is observed in a broad peak at a higher frequency (centered at 5.4 ppm, but spanning out to beyond 10 ppm) that is consistent with D incorporation into predominantly DNA and RNA. In the case of the D-glucose experiments, 61 % of the deuterium is observed in a sharp resonance peak at 0.34 ppm, also consistent with D incorporation into membrane lipids, the remainder of the D is observed at a broad resonance peak centered at 4.3 ppm, consistent with D enrichment in glycogen. Deuterium abundance in the E. coli cells grown in 10 % D2O is nearly 2X greater than that grown with 10 % D-glucose. Very subtle differences are observed in both the 1H and 13C solid-state NMR experiments, most notably in the spectral region corresponding to glycogen H and C, respectively. Interestingly, whereas in both experiments the predominant site of incorporation was in the membrane lipids, the line width of the aliphatic-D resonance in the D2O enriched experiment is 67 % wider than that observed in the D-glucose enriched experiment. This difference could be due to greater residual 1H-2H dipolar coupling in membrane lipids synthesized with 10 % D2O due to D being incorporated during NADP(D) reduction of the fatty acid precursor during synthesis and the H-glucose being the source of carbon and hydrogen starting with acetyl-CoA. In the case of the D-glucose experiment, the narrower absorption line may be consistent with individual FA's being more homogeneously deuterated. Analysis of the membrane lipids is currently being performed via GCMS in order to gain potentially more insight to guide interpretation of the 2H solid state NMR spectra.

Three-dimensional Imaging for Large LArTPCs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chao, C.; Qian, X.; Viren, B.

2017-12-14

High-performance event reconstruction is critical for current and future massive liquid argon time projection chambers (LArTPCs) to realize their full scientic potential. LArTPCs with readout using wire planes provides a limited number of 2D projections. In general, without a pixel-type readout it is challenging to achieve unambiguous 3D event reconstruction. As a remedy, we present a novel 3D imaging method, Wire-Cell, which incorporates the charge and sparsity information in addition to the time and geometry through simple and robust mathematics.

Impact Study of Synthetic and Alternative Fuel Usage in Army Aircraft Propulsion Systems.

DTIC Science & Technology

1981-07-01

oil were Included for comparison. The elastomers tested represented all of the non- metallic materials found in aircraft fuel systems. The study on...a Buna N liner (adjacent to the fuel)surrounded by a wire braid and a special butyl-rubber outer hose . These hoses comformed to the following...or Stratoflex Incorporated. The hose usually has a nylon or wire braid on the outside conforming to MIL-C-83291 or MIL-C-83797. Two hose designs are

Online Cable Tester and Rerouter

NASA Technical Reports Server (NTRS)

Lewis, Mark; Medelius, Pedro

2012-01-01

Hardware and algorithms have been developed to transfer electrical power and data connectivity safely, efficiently, and automatically from an identified damaged/defective wire in a cable to an alternate wire path. The combination of online cable testing capabilities, along with intelligent signal rerouting algorithms, allows the user to overcome the inherent difficulty of maintaining system integrity and configuration control, while autonomously rerouting signals and functions without introducing new failure modes. The incorporation of this capability will increase the reliability of systems by ensuring system availability during operations.

A One Chip Hardened Solution for High Speed SpaceWire System Implementations. Session: Components

NASA Technical Reports Server (NTRS)

Marshall, Joseph R.; Berger, Richard W.; Rakow, Glenn P.

2007-01-01

An Application Specific Integrated Circuit (ASIC) that implements the SpaceWire protocol has been developed in a radiation hardened 0.25 micron CMOS technology. This effort began in March 2003 as a joint development between the NASA Goddard Space Flight Center (GSFC) and BAE Systems. The BAE Systems SpaceWire ASIC is comprised entirely of reusable core elements, many of which are already flight-proven. It incorporates a router with 4 SpaceWire ports and two local ports, dual PC1 bus interfaces, a microcontroller, 32KB of internal memory, and a memory controller for additional external memory use. The SpaceWire cores are also reused in other ASICs under development. The SpaceWire ASIC is planned for use on the Geostationary Operational Environmental Satellites (GOES)-R, the Lunar Reconnaissance Orbiter (LRO) and other missions. Engineering and flight parts have been delivered to programs and users. This paper reviews the SpaceWire protocol and those elements of it that have been built into the current and next SpaceWire reusable cores and features within the core that go beyond the current standard and can be enabled or disabled by the user. The adaptation of SpaceWire to BAE Systems' On Chip Bus (OCB) for compatibility with the other reusable cores will be reviewed and highlighted. Optional configurations within user systems and test boards will be shown. The physical implementation of the design will be described and test results from the hardware will be discussed. Application of this ASIC and other ASICs containing the SpaceWire cores and embedded microcontroller to Plug and Play and reconfigurable implementations will be described. Finally, the BAE Systems roadmap for SpaceWire developments will be updated, including some products already in design as well as longer term plans.

Phase slips in superconducting weak links

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kimmel, Gregory; Glatz, Andreas; Aranson, Igor S.

2017-01-01

Superconducting vortices and phase slips are primary mechanisms of dissipation in superconducting, superfluid, and cold-atom systems. While the dynamics of vortices is fairly well described, phase slips occurring in quasi-one- dimensional superconducting wires still elude understanding. The main reason is that phase slips are strongly nonlinear time-dependent phenomena that cannot be cast in terms of small perturbations of the superconducting state. Here we study phase slips occurring in superconducting weak links. Thanks to partial suppression of superconductivity in weak links, we employ a weakly nonlinear approximation for dynamic phase slips. This approximation is not valid for homogeneous superconducting wires andmore » slabs. Using the numerical solution of the time-dependent Ginzburg-Landau equation and bifurcation analysis of stationary solutions, we show that the onset of phase slips occurs via an infinite period bifurcation, which is manifested in a specific voltage-current dependence. Our analytical results are in good agreement with simulations.« less

Power and energy of exploding wires

DOE PAGES

Valancius, Cole J.; Garasi, Christopher J.; O?Malley, Patrick D.

2017-01-01

Exploding wires are used in many high-energy applications, such as initiating explosives. Previous work analyzing gold wire burst in detonator applications has shown burst current and action metrics to be inconsistent with burst phenomenon across multiple firing-sets. Energy density better captures the correlation between different wire geometries, different electrical inputs, and explosive initiation. This idea has been expanded upon, to analyze the burst properties in power-energy space. Further inconsistencies in the understanding of wire burst and its relation to peak voltage have been found. An argument will be made for redefining the definition of burst. The result is a moremore » broad understanding of rapid metal phase transition and the initiation of explosives in EBW applications.« less

Power and energy of exploding wires

DOE Office of Scientific and Technical Information (OSTI.GOV)

Valancius, Cole J.; Garasi, Christopher J.; O?Malley, Patrick D.

Exploding wires are used in many high-energy applications, such as initiating explosives. Previous work analyzing gold wire burst in detonator applications has shown burst current and action metrics to be inconsistent with burst phenomenon across multiple firing-sets. Energy density better captures the correlation between different wire geometries, different electrical inputs, and explosive initiation. This idea has been expanded upon, to analyze the burst properties in power-energy space. Further inconsistencies in the understanding of wire burst and its relation to peak voltage have been found. An argument will be made for redefining the definition of burst. The result is a moremore » broad understanding of rapid metal phase transition and the initiation of explosives in EBW applications.« less

Microwave Power Combiners for Signals of Arbitrary Amplitude

NASA Technical Reports Server (NTRS)

Conroy, Bruce; Hoppe, Daniel

2009-01-01

Schemes for combining power from coherent microwave sources of arbitrary (unequal or equal) amplitude have been proposed. Most prior microwave-power-combining schemes are limited to sources of equal amplitude. The basic principle of the schemes now proposed is to use quasi-optical components to manipulate the polarizations and phases of two arbitrary-amplitude input signals in such a way as to combine them into one output signal having a specified, fixed polarization. To combine power from more than two sources, one could use multiple powercombining stages based on this principle, feeding the outputs of lower-power stages as inputs to higher-power stages. Quasi-optical components suitable for implementing these schemes include grids of parallel wires, vane polarizers, and a variety of waveguide structures. For the sake of brevity, the remainder of this article illustrates the basic principle by focusing on one scheme in which a wire grid and two vane polarizers would be used. Wire grids are the key quasi-optical elements in many prior equal-power combiners. In somewhat oversimplified terms, a wire grid reflects an incident beam having an electric field parallel to the wires and passes an incident beam having an electric field perpendicular to the wires. In a typical prior equal-power combining scheme, one provides for two properly phased, equal-amplitude signals having mutually perpendicular linear polarizations to impinge from two mutually perpendicular directions on a wire grid in a plane oriented at an angle of 45 with respect to both beam axes. The wires in the grid are oriented to pass one of the incident beams straight through onto the output path and to reflect the other incident beam onto the output path along with the first-mentioned beam.

Characterization and application of Shape Memory Alloy wires for micro and meso positioning systems

NASA Astrophysics Data System (ADS)

Khan, Afzal

The properties of Shape Memory Alloy (SMA) wires are determined by experimentation, and previously used experimental equipment contributes to measurement errors in data. In this study, various characterization experiments are designed and carried out using a precision characterization instrument for shape memory alloy wires to determine the properties and parameters of the alloy. These experiments demonstrate the behavior of SMA wires under different thermal and loading conditions as they occur in actuation applications. As SMA wires go through phase transformation, a significant amount of contraction force is produced. This actuation force has been used in bias spring actuators and differential actuators. In this dissertation, the force generated during the twinning of martensite is used to actuate positioning systems with small displacements at the micrometer level. A micropositioning system is designed and tested that has a positioning accuracy of about +/-0.15 mum. A relation between the current input and the displacement output is determined for the specific preload. The transformation force generated during the phase change from martensite to austenite is used as an actuation force for a second positioning system that uses linear bearing with a displacement range of about a millimeter. This positioning system actuated with a single nitinol wire and guided by symmetric parallel diaphragm flexures, was designed and tested. The actuation is repeatable to about +/-15 mum with variation of about +/-5 mum in postion at steady temperature.

Evaluation of in vivo solid phase microextraction for minimally invasive analysis of nonvolatile phytochemicals in Amazonian plants.

PubMed

Musteata, Florin Marcel; Sandoval, Manuel; Ruiz-Macedo, Juan C; Harrison, Kathleen; McKenna, Dennis; Millington, William

2016-08-24

Although solid phase microextraction (SPME) has been used extensively for fingerprinting volatile compounds emitted by plants, there are very few such reports for direct insertion SPME. In this research, direct contact of SPME probes with the interstitial fluid of plants was investigated as a method for phytochemical analysis. Medicinal plants from the Amazon have been the source of numerous drugs used in western medicine. However, a large number of species used in traditional medicine have not been characterized chemically, partly due to the difficulty of field work. In this project, the phytochemical composition of plants from several genera was fingerprinted by combining convenient field sampling by solid phase microextraction (SPME) with laboratory analysis by LC-MS. The new method was compared with classical sampling followed by liquid extraction (LE). SPME probes were prepared by coating stainless steel wires with a mixture of polyacrylonitrile and either RP-amide or HS-F5 silica particles. Sampling was performed by inserting the microextraction probes into various tissues of living plants in their natural environment. After in vivo extraction, the probes were sealed under vacuum and refrigerated until analyzed. The probes were desorbed in mobile phase and analyzed on a Waters Acquity UPLC with triple quadrupole mass spectrometer in positive ion mode. Twenty Amazonian plant species were sampled and unique metabolomic fingerprints were obtained. In addition, quantitative analysis was performed for previously identified compounds in three species. Comparison of the fingerprints obtained by in vivo SPME with those obtained by LE showed that 27% of the chromatographic features were unique to SPME, 57% were unique to LE, and 16% were common to both methods. In vivo SPME caused minimal damage to the plants, was much faster than traditional liquid extraction, and provided unique fingerprints for all investigated plants. SPME revealed unique chromatographic features, undetected by traditional extraction, although it produced only half as many peaks as ethanol extraction. Copyright © 2016 Elsevier B.V. All rights reserved.

Electrical control of a solid-state flying qubit.

PubMed

Yamamoto, Michihisa; Takada, Shintaro; Bäuerle, Christopher; Watanabe, Kenta; Wieck, Andreas D; Tarucha, Seigo

2012-03-18

Solid-state approaches to quantum information technology are attractive because they are scalable. The coherent transport of quantum information over large distances is a requirement for any practical quantum computer and has been demonstrated by coupling super-conducting qubits to photons. Single electrons have also been transferred between distant quantum dots in times shorter than their spin coherence time. However, until now, there have been no demonstrations of scalable 'flying qubit' architectures-systems in which it is possible to perform quantum operations on qubits while they are being coherently transferred-in solid-state systems. These architectures allow for control over qubit separation and for non-local entanglement, which makes them more amenable to integration and scaling than static qubit approaches. Here, we report the transport and manipulation of qubits over distances of 6 µm within 40 ps, in an Aharonov-Bohm ring connected to two-channel wires that have a tunable tunnel coupling between channels. The flying qubit state is defined by the presence of a travelling electron in either channel of the wire, and can be controlled without a magnetic field. Our device has shorter quantum gates (<1 µm), longer coherence lengths (∼86 µm at 70 mK) and higher operating frequencies (∼100 GHz) than other solid-state implementations of flying qubits.

Review of Slow-Wave Structures

NASA Technical Reports Server (NTRS)

Wallett, Thomas M.; Qureshi, A. Haq

1994-01-01

The majority of recent theoretical and experimental reports published in the literature dealing with helical slow-wave structures focus on the dispersion characteristics and their effects due to the finite helix wire thickness and attenuation, dielectric loading, metal loading, and the introduction of plasma. In many papers, an effective dielectric constant is used to take into account helix wire dimensions and conductivity losses, while the propagation constant of the signal and the interaction impedance of the structure are found to depend on the surface resistivity of the helix. Also, various dielectric supporting rods are simulated by one or several uniform cylinders having an effective dielectric constant, while metal vane loading and plasma effects are incorporated in the effective dielectric constant. The papers dealing with coupled cavities and folded or loaded wave guides describe equivalent circuit models, efficiency enhancement, and the prediction of instabilities for these structures. Equivalent circuit models of various structures are found using computer software programs SUPERFISH and TOUCHSTONE. Efficiency enhancement in tubes is achieved through dynamic velocity and phase adjusted tapers using computer techniques. The stability threshold of unwanted antisymmetric and higher order modes is predicted using SOS and MAGIC codes and the dependence of higher order modes on beam conductance, section length, and effective Q of a cavity is shown.

Evaluation of the slurry management strategy and the integration of the composting technology in a pig farm - Agronomical and environmental implications.

PubMed

Sáez, José A; Clemente, Rafael; Bustamante, M Ángeles; Yañez, David; Bernal, M Pilar

2017-05-01

The changes in livestock production systems towards intensification frequently lead to an excess of manure generation with respect to the agricultural land available for its soil application. However, treatment technologies can help in the management of manures, especially in N-surplus areas. An integrated slurry treatment system based on solid-liquid separation, aerobic treatment of the liquid and composting the solid fraction was evaluated in a pig farm (sows and piglets) in the South of Spain. Solid fraction separation using a filter band connected to a screw press had low efficiency (38%), which was greatly improved incorporating a rotatory sieve (61%). The depuration system was very efficient for the liquid, with total removal of 84% total solids, 87% volatile solids, and 98% phosphorus. Two composting systems were tested through mechanical turning of: 1- a mixture of solid fraction stored for 1 month after solid-liquid separation and cereal straw; 2- recently-separated solid fraction mixed with cotton gin waste. System 2 was recommended for the farm, as it exhibited a fast temperature rise and a long thermophilic phase to ensure compost sanitisation, and high recovery of nutrients (TN 77%, P and K > 85%) and organic matter (45%). The composts obtained were mature, stable and showed a high degree of humification of their organic matter, absence of phytotoxicity and concentrations of nutrients similar to other composts from pig manure or separated slurry solids. However, the introduction of slurry from piglets into the solid-liquid separation system should be avoided in order to reduce the content of Zn in the compost, which lowers its quality. The slurry separation followed by composting of the solid fraction using a passive windrow system, and aeration of the liquid phase, was the most recommendable procedure for the reduction of GHG emissions on the farm. Copyright © 2017 Elsevier Ltd. All rights reserved.

Probing spin helical surface states in topological HgTe nanowires

NASA Astrophysics Data System (ADS)

Ziegler, J.; Kozlovsky, R.; Gorini, C.; Liu, M.-H.; Weishäupl, S.; Maier, H.; Fischer, R.; Kozlov, D. A.; Kvon, Z. D.; Mikhailov, N.; Dvoretsky, S. A.; Richter, K.; Weiss, D.

2018-01-01

Nanowires with helical surface states represent key prerequisites for observing and exploiting phase-coherent topological conductance phenomena, such as spin-momentum locked quantum transport or topological superconductivity. We demonstrate in a joint experimental and theoretical study that gated nanowires fabricated from high-mobility strained HgTe, known as a bulk topological insulator, indeed preserve the topological nature of the surface states, that moreover extend phase-coherently across the entire wire geometry. The phase-coherence lengths are enhanced up to 5 μ m when tuning the wires into the bulk gap, so as to single out topological transport. The nanowires exhibit distinct conductance oscillations, both as a function of the flux due to an axial magnetic field and of a gate voltage. The observed h /e -periodic Aharonov-Bohm-type modulations indicate surface-mediated quasiballistic transport. Furthermore, an in-depth analysis of the scaling of the observed gate-dependent conductance oscillations reveals the topological nature of these surface states. To this end we combined numerical tight-binding calculations of the quantum magnetoconductance with simulations of the electrostatics, accounting for the gate-induced inhomogeneous charge carrier densities around the wires. We find that helical transport prevails even for strongly inhomogeneous gating and is governed by flux-sensitive high-angular momentum surface states that extend around the entire wire circumference.

Enhancing electron transport in molecular wires by insertion of a ferrocene center.

PubMed

Sun, Yan-Yan; Peng, Zheng-Lian; Hou, Rong; Liang, Jing-Hong; Zheng, Ju-Fang; Zhou, Xiao-Yi; Zhou, Xiao-Shun; Jin, Shan; Niu, Zhen-Jiang; Mao, Bing-Wei

2014-02-14

We have determined the conductance of alkane-linked ferrocene molecules with carboxylic acid anchoring groups using the STM break junction technique, and three sets of conductance values were found, i.e. high conductance (HC), medium conductance (MC) and low conductance (LC) values. The enhancing effect of the incorporated ferrocene on the electron transport in saturated alkane molecular wires is demonstrated by the increased conductance of the ferrocene molecules, attributed to the reduction of the tunneling barrier and the HOMO-LUMO gap induced by the insertion of ferrocene. Furthermore, the electron-withdrawing carbonyl group on the unconjugated backbone has little or no influence on single-molecule conductance. The current work provides a feasible approach for the design of high-performance molecular wires.

Nanostructures Enabled by On-Wire Lithography (OWL)

PubMed Central

Braunschweig, Adam B.; Schmucker, Abrin L.; Wei, Wei David; Mirkin, Chad A.

2010-01-01

Nanostructures fabricated by a novel technique, termed On-Wire-Lithography (OWL), can be combined with organic and biological molecules to create systems with emergent and highly functional properties. OWL is a template-based, electrochemical process for forming gapped cylindrical structures on a solid support, with feature sizes (both gap and segment length) that can be controlled on the sub-100 nm length scale. Structures prepared by this method have provided valuable insight into the plasmonic properties of noble metal nanomaterials and have formed the basis for novel molecular electronic, encoding, and biological detection devices. PMID:20396668

Nail-like targets for laser plasma interaction experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pasley, J; Wei, M; Shipton, E

2007-12-18

The interaction of ultra-high power picosecond laser pulses with solid targets is of interest both for benchmarking the results of hybrid particle in cell (PIC) codes and also for applications to re-entrant cone guided fast ignition. We describe the construction of novel targets in which copper/titanium wires are formed into 'nail-like' objects by a process of melting and micromachining, so that energy can be reliably coupled to a 24 {micro}m diameter wire. An extreme-ultraviolet image of the interaction of the Titan laser with such a target is shown.

Influence of encapsulated functional lipids on crystal structure and chemical stability in solid lipid nanoparticles: Towards bioactive-based design of delivery systems.

PubMed

Salminen, Hanna; Gömmel, Christina; Leuenberger, Bruno H; Weiss, Jochen

2016-01-01

We investigated the influence of physicochemical properties of encapsulated functional lipids--vitamin A, β-carotene and ω-3 fish oil--on the structural arrangement of solid lipid nanoparticles (SLN). The relationship between the crystal structure and chemical stability of the incorporated bioactive lipids was evaluated with different emulsifier compositions of a saponin-rich, food-grade Quillaja extract alone or combined with high-melting or low-melting lecithins. The major factors influencing the structural arrangement and chemical stability of functional lipids in solid lipid dispersions were their solubility in the aqueous phase and their crystallization temperature in relation to that of the carrier lipid. The results showed that the stabilization of the α-subcell crystals in the lattice of the carrier lipid is a key parameter for forming stable solid lipid dispersions. This study contributes to a better understanding of SLN as a function of the bioactive lipid. Copyright © 2015 Elsevier Ltd. All rights reserved.

Necessary Conditions for Accurate, Transient Hot-Wire Measurements of the Apparent Thermal Conductivity of Nanofluids are Seldom Satisfied

NASA Astrophysics Data System (ADS)

Antoniadis, Konstantinos D.; Tertsinidou, Georgia J.; Assael, Marc J.; Wakeham, William A.

2016-08-01

The paper considers the conditions that are necessary to secure accurate measurement of the apparent thermal conductivity of two-phase systems comprising nanoscale particles of one material suspended in a fluid phase of a different material. It is shown that instruments operating according to the transient hot-wire technique can, indeed, produce excellent measurements when a finite element method (FEM) is employed to describe the instrument for the exact geometry of the hot wire. Furthermore, it is shown that an approximate analytic solution can be employed with equal success, over the time range of 0.1 s to 1 s, provided that (a) two wires are employed, so that end effects are canceled, (b) each wire is very thin, less than 30 \\upmu m diameter, so that the line source model and the corresponding corrections are valid, (c) low values of the temperature rise, less than 4 K, are employed in order to minimize the effect of convection on the heat transfer in the time of measurement of 1 s, and (d) insulated wires are employed for measurements in electrically conducting or polar liquids to avoid current leakage or other electrical distortions. According to these criteria, a transient hot-wire instrument has been designed, constructed, and employed for the measurement of the enhancement of the thermal conductivity of water when TiO2 or multi-wall carbon nanotubes (MWCNT) are added. These new results, together with a critical evaluation of other measurements, demonstrate the importance of proper implementation of the technique.

The Modeling of Vibration Damping in SMA Wires

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reynolds, D R; Kloucek, P; Seidman, T I

Through a mathematical and computational model of the physical behavior of shape memory alloy wires, this study shows that localized heating and cooling of such materials provides an effective means of damping vibrational energy. The thermally induced pseudo-elastic behavior of a shape memory wire is modeled using a continuum thermodynamic model and solved computationally as described by the authors in [23]. Computational experiments confirm that up to 80% of an initial shock of vibrational energy can be eliminated at the onset of a thermally-induced phase transformation through the use of spatially-distributed transformation regions along the length of a shape memorymore » alloy wire.« less

Incorporation of thorium in the rhabdophane structure: Synthesis and characterization of Pr1-2xCaxThxPO4·nH2O solid solutions

NASA Astrophysics Data System (ADS)

Qin, Danwen; Mesbah, Adel; Gausse, Clémence; Szenknect, Stéphanie; Dacheux, Nicolas; Clavier, Nicolas

2017-08-01

Thorium incorporation in the rhabdophane structure as Pr1-2xCaxThxPO4·nH2O solid solutions was successfully achieved and resulted in the preparation of a low temperature precursor of the monazite-cheralite type Pr1-2xCaxThxPO4. The rhabdophane compounds are considered as potential neoformed phases in case of release of actinides from the phosphate-based ceramic wasteforms envisaged to host radionuclides in the back-end of the nuclear fuel cycle. A multiparametric study was thus undertaken to specify the wet chemistry conditions (starting stoichiometry, temperature, heating time) leading to single phase Pr1-2xCaxThxPO4·nH2O powdered samples. The excess of calcium appeared to be a prevailing factor with a suggested initial Ca:Th ratio being equal to 10. Similarly, the recommended heating time should exceed 4 days while the optimal temperature of synthesis is 110 °C. Under these conditions, the stability domain of Pr1-2xCaxThxPO4·nH2O ranged from x = 0.00 to x = 0.15. After heating at 1100 °C under air during 6 h, rhabdophane-type samples were fully converted into the highly durable Pr1-2xCaxThxPO4 cheralite ceramic wasteform.

Composite electrolyte with proton conductivity for low-temperature solid oxide fuel cell

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raza, Rizwan, E-mail: razahussaini786@gmail.com; Department of Energy Technology, Royal Institute of Technology, KTH, Stockholm 10044; Ahmed, Akhlaq

In the present work, cost-effective nanocomposite electrolyte (Ba-SDC) oxide is developed for efficient low-temperature solid oxide fuel cells (LTSOFCs). Analysis has shown that dual phase conduction of O{sup −2} (oxygen ions) and H{sup +} (protons) plays a significant role in the development of advanced LTSOFCs. Comparatively high proton ion conductivity (0.19 s/cm) for LTSOFCs was achieved at low temperature (460 °C). In this article, the ionic conduction behaviour of LTSOFCs is explained by carrying out electrochemical impedance spectroscopy measurements. Further, the phase and structure analysis are investigated by X-ray diffraction and scanning electron microscopy techniques. Finally, we achieved an ionic transport numbermore » of the composite electrolyte for LTSOFCs as high as 0.95 and energy and power density of 90% and 550 mW/cm{sup 2}, respectively, after sintering the composite electrolyte at 800 °C for 4 h, which is promising. Our current effort toward the development of an efficient, green, low-temperature solid oxide fuel cell with the incorporation of high proton conductivity composite electrolyte may open frontiers in the fields of energy and fuel cell technology.« less

Preconditioned wire array Z-pinches driven by a double pulse current generator

NASA Astrophysics Data System (ADS)

Wu, Jian; Lu, Yihan; Sun, Fengju; Li, Xingwen; Jiang, Xiaofeng; Wang, Zhiguo; Zhang, Daoyuan; Qiu, Aici; Lebedev, Sergey

2018-07-01

Suppression of the core-corona structure and wire ablation in wire array Z-pinches is investigated using a novel double pulse current generator ‘Qin-1’ facility. The ‘Qin-1’ facility allows coupling a ∼10 kA 20 ns prepulse generator with a ∼0.8 MA 160 ns main current generator. The tailored prepulse current preheats wires to a gaseous state and the time interval between the prepulse and the main current pulse allows formation of a more uniform mass distribution for the implosion. The implosion of a gasified two aluminum-wire array showed no ablation phase and allowed all array mass to participate in the implosion. The initial perturbations formed from the inhomogeneous ablation were suppressed, however, the magneto Rayleigh–Taylor (MRT) instability during the implosion was still significant and further researches on the generation and development of the MRT instabilities of this gasified wire array are needed.

Seeded Nanowire and Microwire Growth from Lithium Alloys.

PubMed

Han, Sang Yun; Boebinger, Matthew G; Kondekar, Neha P; Worthy, Trevor J; McDowell, Matthew T

2018-06-06

Although vapor-liquid-solid (VLS) growth of nanowires from alloy seed particles is common in various semiconductor systems, related wire growth in all-metal systems is rare. Here, we report the spontaneous growth of nano- and microwires from metal seed particles during the cooling of Li-rich bulk alloys containing Au, Ag, or In. The as-grown wires feature Au-, Ag-, or In-rich metal tips and LiOH shafts; the results indicate that the wires grow as Li metal and are converted to polycrystalline LiOH during and/or after growth due to exposure to H 2 O and O 2 . This new process is a simple way to create nanostructures, and the findings suggest that metal nanowire growth from alloy seeds is possible in a variety of systems.

Wiring up pre-characterized single-photon emitters by laser lithography

NASA Astrophysics Data System (ADS)

Shi, Q.; Sontheimer, B.; Nikolay, N.; Schell, A. W.; Fischer, J.; Naber, A.; Benson, O.; Wegener, M.

2016-08-01

Future quantum optical chips will likely be hybrid in nature and include many single-photon emitters, waveguides, filters, as well as single-photon detectors. Here, we introduce a scalable optical localization-selection-lithography procedure for wiring up a large number of single-photon emitters via polymeric photonic wire bonds in three dimensions. First, we localize and characterize nitrogen vacancies in nanodiamonds inside a solid photoresist exhibiting low background fluorescence. Next, without intermediate steps and using the same optical instrument, we perform aligned three-dimensional laser lithography. As a proof of concept, we design, fabricate, and characterize three-dimensional functional waveguide elements on an optical chip. Each element consists of one single-photon emitter centered in a crossed-arc waveguide configuration, allowing for integrated optical excitation and efficient background suppression at the same time.

Proceedings of the International Wire and Cable Symposium (40th) Held in St. Louis, Missouri on 18-21 November 1991

DTIC Science & Technology

1991-11-01

S. Windeler, Bell Laboratories- 1970 Dr. 0. Leuchs, Kable and Metalwerke-"A New Self -Ex- "A Low Capacitance Cable for the T2 Digital Trans...Pickering is a member implementation as well as test and evaluation, of the New York Rubber Group, the Wire production base planning and product assurance...metallic German power utilities. ground or phase wire. The thus created new aerial cable changes in its mechanical characteristics only unimportantly

Suppression of superconductivity in disordered interacting wires.

PubMed

Pesin, D A; Andreev, A V

2006-09-15

We study superconductivity suppression due to thermal fluctuations in disordered wires using the replica nonlinear sigma-model (NLsigmaM). We show that in addition to the thermal phase slips there is another type of fluctuations that result in a finite resistivity. These fluctuations are described by saddle points in NLsigmaM and cannot be treated within the Ginzburg-Landau approach. The contribution of such fluctuations to the wire resistivity is evaluated with exponential accuracy. The magnetoresistance associated with this contribution is negative.

Experimental Constraints on Reconstruction of Archean Seawater Ni Isotopic Composition from Banded Iron Formations

NASA Astrophysics Data System (ADS)

Wang, S.; Wasylenki, L.

2016-12-01

Ni isotope systematics in banded iron formations (BIFs) potentially recorded the Ni isotopic composition of ancient seawater during the Precambrian Eon[1]. The use of BIFs as seawater proxies requires knowing how Ni isotopes fractionated during initial incorporation into iron-rich sediments and during early diagenesis. We conducted experiments to investigate Ni isotope behavior during coprecipitation with ferrihydrite and transformation of ferrihydrite to hematite. Ferrihydrite synthesis at neutral pH demonstrated that dissolved Ni was variably heavier than coprecipitated Ni (Δ60/58Ni = +0.08 to +0.50 ‰), in contrast to the constant offset observed earlier during adsorption to pre-existing ferrihydrite[2]. Experiments at lower pH (<7) yielded negative values of Δ60/58Ni ( -0.18 ‰), suggesting enrichment in heavier isotopes of structurally incorporated Ni relative to dissolved and adsorbed Ni, possibly due to the presence of a small amount of highly fractionated tetrahedral Ni2+ in the ferrihydrite structure. We model our results as equilibrium fractionation among three pools of Ni with systematically varied proportions. We synthesized hematite by transforming Ni-bearing ferrihydrite in aqueous solution at 100 °C and observed significant Ni release from solids (up to 60 %) as pH dropped from 7 to 4.5 - 5.5 during phase transformation. Rinsing hematite with acetic acid released very little Ni (presumably surface-adsorbed) compared to the amounts remaining in solid residues (presumably incorporated). We infer that Δ60/58Ni values (-0.04 to +0.77 ‰) observed in hematite experiments likely reflect Rayleigh fractionation between incorporated and dissolved Ni. The final hematite was slightly lighter than the ferrihydrite had been (by 0.08 ‰), indicating that this phase transformation results in very limited change in Ni isotopic composition, given current analytical uncertainty of ± 0.09 ‰. [1] Wasylenki and Wang (2016) Goldschmidt; [2] Wasylenki et al. (2015) ChemGeol.

The Quantum Socket: Wiring for Superconducting Qubits - Part 1

NASA Astrophysics Data System (ADS)

McConkey, T. G.; Bejanin, J. H.; Rinehart, J. R.; Bateman, J. D.; Earnest, C. T.; McRae, C. H.; Rohanizadegan, Y.; Shiri, D.; Mariantoni, M.; Penava, B.; Breul, P.; Royak, S.; Zapatka, M.; Fowler, A. G.

Quantum systems with ten superconducting quantum bits (qubits) have been realized, making it possible to show basic quantum error correction (QEC) algorithms. However, a truly scalable architecture has not been developed yet. QEC requires a two-dimensional array of qubits, restricting any interconnection to external classical systems to the third axis. In this talk, we introduce an interconnect solution for solid-state qubits: The quantum socket. The quantum socket employs three-dimensional wires and makes it possible to connect classical electronics with quantum circuits more densely and accurately than methods based on wire bonding. The three-dimensional wires are based on spring-loaded pins engineered to insure compatibility with quantum computing applications. Extensive design work and machining was required, with focus on material quality to prevent magnetic impurities. Microwave simulations were undertaken to optimize the design, focusing on the interface between the micro-connector and an on-chip coplanar waveguide pad. Simulations revealed good performance from DC to 10 GHz and were later confirmed against experimental measurements.

n-hydrocarbons conversions over metal-modified solid acid catalysts

NASA Astrophysics Data System (ADS)

Zarubica, A.; Ranđelović, M.; Momčilović, M.; Radulović, N.; Putanov, P.

2013-12-01

The quality of a straight-run fuel oil can be improved if saturated n-hydrocarbons of low octane number are converted to their branched counterparts. Poor reactivity of traditional catalysts in isomerization reactions imposed the need for the development of new catalysts among which noble metal promoted acid catalysts, liquid and/or solid acid catalysts take a prominent place. Sulfated zirconia and metal promoted sulfated zirconia exhibit high activity for the isomerization of light alkanes at low temperatures. The present paper highlights the original results which indicate that the modification of sulfated zirconia by incorporation of metals (platinum and rhenium) significantly affects catalytic performances in n-hydrocarbon conversion reactions. Favourable activity/selectivity of the promoted sulfated zirconia depends on the crystal phase composition, critical crystallites sizes, platinum dispersion, total acidity and type of acidity. Attention is also paid to the recently developed solid acid catalysts used in other conversion reactions of hydrocarbons.

Ion-Selective Electrodes.

ERIC Educational Resources Information Center

Arnold, Mark A.; Meyerhoff, Mark E.

1984-01-01

Literature on ion-selective electrodes (ISEs) is reviewed in seven sections: books, conferences, reviews; potentiometric membrane electrodes; glass and solid-state membrane electrodes; liquid and polymer membrane ISEs; coated wire electrodes, ion-selective field effect transistors, and microelectrodes; gas sensors and selective bioelectrode…

30 CFR 77.704-1 - Work on high-voltage lines.

Code of Federal Regulations, 2011 CFR

2011-07-01

... grounded or solid wye-connected systems, the neutral wire is the system grounding medium. In the case of an ungrounded power system, either the steel armor or conduit enclosing the system or a surface grounding field...

30 CFR 77.704-1 - Work on high-voltage lines.

Code of Federal Regulations, 2010 CFR

2010-07-01

... grounded or solid wye-connected systems, the neutral wire is the system grounding medium. In the case of an ungrounded power system, either the steel armor or conduit enclosing the system or a surface grounding field...

Tuning of shell thickness of solid lipid particles impacts the chemical stability of encapsulated ω-3 fish oil.

PubMed

Salminen, Hanna; Helgason, Thrandur; Kristinsson, Bjarki; Kristbergsson, Kristberg; Weiss, Jochen

2017-03-15

This study demonstrates that tuning the shell thickness of lipid particles can modulate their oxidative stability. We hypothesized that a thick crystallized shell around the incorporated fish oil would improve the oxidative stability due to the reduced diffusion of prooxidants and oxygen. We prepared solid lipid nanoparticles (5%w/w lipid phase, 1.5%w/w surfactant, pH 7) by using different ratios of tristearin as carrier lipid and ω-3 fish oil as incorporated liquid lipid stabilized by high- or low-melting lecithin. The physical, polymorphic and oxidative stability of the lipid particles was assessed. The high-melting lecithin was the key in inducing the formation of a solidified tristearin shell around the lipid particles by interfacial heterogeneous nucleation. Lipid particles containing a higher ratio of tristearin showed a better oxidative stability. The results revealed that a crystallized tristearin layer above 10nm was required to inhibit oxidation of the incorporated fish oil. This cut-off was shown for lipid particles containing 50-60% fish oil. This research gives important insights into understanding the relation between the thickness of the crystallized shell around the lipid particles and their chemical stability. Copyright © 2016 Elsevier Inc. All rights reserved.

Gold-Catalyzed Solid-Phase Synthesis of 3,4-Dihydropyrazin-2(1H)-ones: Relevant Pharmacophores and Peptide Backbone Constraints.

PubMed

Přibylka, Adam; Krchňák, Viktor

2017-11-13

Here, we report the efficient solid-phase synthesis of N-propargyl peptides using Fmoc-amino acids and propargyl alcohol as key building blocks. Gold-catalyzed nucleophilic addition to the triple bond induced C-N bond formation, which triggered intramolecular cyclization, yielding 1,3,4-trisubstituted-5-methyl-3,4-dihydropyrazin-2(1H)-ones. Conformations of acyclic and constrained peptides were compared using a two-step conformer distribution analysis at the molecular mechanics level and density functional theory. The results indicated that the incorporation of heterocyclic molecular scaffold into a short peptide sequence adopted extended conformation of peptide chain. The amide bond adjacent to the constraint did not show significant preference for either cis or trans isomerism. Prepared model compounds demonstrate a proof of concept for gold-catalyzed polymer-supported synthesis of variously substituted 3,4-dihydropyrazin-2(1H)-ones for applications in drug discovery and peptide backbone constraints.

Hi-rel lead-free printed wiring assemblies

NASA Technical Reports Server (NTRS)

Mehta, A. C.; Bonner, J. K.; Castillo, L. del

2002-01-01

The use of lead in electronics has come under increasing scrutiny. Given the trends in both Japan and Europe, it is highly likely that the U.S. will be driven by commercial interests to phase out of lead in electronics usage. This paper presents data collected on a recent NASA project to focus on finding suitable alternatives to eutectic tin-lead solders and solder pastes. The first phase of this project dealt with determining the most feasible candidates to replace tin-lead and to determine suitable processing operations in assemblies printed wiring boards.

Force delivery of NiTi orthodontic arch wire at different magnitude of deflections and temperatures: A finite element study.

PubMed

Razali, M F; Mahmud, A S; Mokhtar, N

2018-01-01

NiTi arch wires are used widely in orthodontic treatment due to its superelastic and biocompatibility properties. In brackets configuration, the force released from the arch wire is influenced by the sliding resistances developed on the arch wire-bracket contact. This study investigated the evolution of the forces released by a rectangular NiTi arch wire towards possible intraoral temperature and deflection changes. A three dimensional finite element model was developed to measure the force-deflection behavior of superelastic arch wire. Finite element analysis was used to distinguish the martensite fraction and phase state of arch wire microstructure in relation to the magnitude of wire deflection. The predicted tensile and bending results from the numerical model showed a good agreement with the experimental results. As contact developed between the wire and bracket, binding influenced the force-deflection curve by changing the martensitic transformation plateau into a slope. The arch wire recovered from greater magnitude of deflection released lower force than one recovered from smaller deflection. In contrast, it was observed that the plateau slope increased from 0.66N/mm to 1.1N/mm when the temperature was increased from 26°C to 46°C. Copyright © 2017 Elsevier Ltd. All rights reserved.

Highly sensitive copper fiber-in-tube solid-phase microextraction for online selective analysis of polycyclic aromatic hydrocarbons coupled with high performance liquid chromatography.

PubMed

Sun, Min; Feng, Juanjuan; Bu, Yanan; Luo, Chuannan

2015-08-21

A fiber-in-tube solid-phase microextraction (SPME) device was developed with copper wire and copper tube, which was served as both the substrate and sorbent with high physical strength and good flexibility. Its morphology and surface properties were characterized by scanning electron microscopy and energy dispersive X-ray spectrometry. It was coupled with high performance liquid chromatography (HPLC) equipment by replacing the sample loop of six-port injection valve, building the online SPME-HPLC system conveniently. Using ten polycyclic aromatic hydrocarbons (PAHs) as model analytes, extraction conditions including sampling rate, extraction time, organic content and desorption time were investigated and optimized. The copper fiber-in-tube exhibits excellent extraction efficiency toward PAHs, with enrichment factors from 268 to 2497. The established online SPME-HPLC method provides good linearity (0.05-100μgL(-1)) and low detection limits (0.001-0.01μgL(-1)) for PAHs. It has been used to determine PAHs in water samples, with recoveries in the range of 86.2-115%. Repeatability on the same extraction tube is in the range of 0.6-3.6%, and repeatability among three tubes is in the range of 5.6-20.1%. Compared with phthalates, anilines and phenols, the copper fiber-in-tube possesses good extraction selectivity for PAHs. The extraction mechanism is probably related to hydrophobic interaction and π-electron-metal interaction. Copyright © 2015 Elsevier B.V. All rights reserved.

Solution synthesis of lead seeded germanium nanowires and branched nanowire networks and their application as Li-ion battery anodes

NASA Astrophysics Data System (ADS)

Flynn, Grace; Palaniappan, Kumaranand; Sheehan, Martin; Kennedy, Tadhg; Ryan, Kevin M.

2017-06-01

Herein, we report the high density growth of lead seeded germanium nanowires (NWs) and their development into branched nanowire networks suitable for application as lithium ion battery anodes. The synthesis of the NWs from lead seeds occurs simultaneously in both the liquid zone (solution-liquid-solid (SLS) growth) and solvent rich vapor zone (vapor-liquid-solid (VLS) growth) of a high boiling point solvent growth system. The reaction is sufficiently versatile to allow for the growth of NWs directly from either an evaporated catalyst layer or from pre-defined nanoparticle seeds and can be extended to allowing extensive branched nanowire formation in a secondary reaction where these seeds are coated onto existing wires. The NWs are characterized using TEM, SEM, XRD and DF-STEM. Electrochemical analysis was carried out on both the single crystal Pb-Ge NWs and the branched Pb-Ge NWs to assess their suitability for use as anodes in a Li-ion battery. Differential capacity plots show both the germanium wires and the lead seeds cycle lithium and contribute to the specific capacity that is approximately 900 mAh g-1 for the single crystal wires, rising to approximately 1100 mAh g-1 for the branched nanowire networks.

Letter: Entrapment and interaction of an air bubble with an oscillating cavitation bubble

NASA Astrophysics Data System (ADS)

Kannan, Y. S.; Karri, Badarinath; Sahu, Kirti Chandra

2018-04-01

The mechanism of the formation of an air bubble due to an oscillating cavitation bubble in its vicinity is reported from an experimental study using high-speed imaging. The cavitation bubble is created close to the free surface of water using a low-voltage spark circuit comprising two copper electrodes in contact with each other. Before the bubble is created, a third copper wire is positioned in contact with the free surface of water close to the two crossing electrodes. Due to the surface tension at the triple point (wire-water-air) interface, a small dip is observed in the free surface at the point where the wire is immersed. When the cavitation bubble is created, the bubble pushes at the dip while expanding and pulls at it while collapsing. The collapse phase leads to the entrapment of an air bubble at the wire immersion point. During this phase, the air bubble undergoes a "catapult" effect, i.e., it expands to a maximum size and then collapses with a microjet at the free surface. To the best of our knowledge, this mechanism has not been reported so far. A parametric study is also conducted to understand the effects of wire orientation and bubble distance from the free surface.

Low cost, formable, high T(sub c) superconducting wire

NASA Technical Reports Server (NTRS)

Smialek, James L. (Inventor)

1991-01-01

A ceramic superconductivity part such as a wire is produced through the partial oxidation of a specially formulated copper alloy in the core. The alloys contain low level quantities of rare earth and alkaline earth dopant elements. Upon oxidation at high temperature, superconducting oxide phases are formed as a thin film.

Industrial Education. Electricity/Electronics Curriculum Guide, Phase II. Instructional Modules, Level I (9 Week).

ERIC Educational Resources Information Center

Lillo, Robert E.; Soffiotto, Nicholas S.

Designed for students in grades 7 and 8, this electricity/electronics curriculum guide contains instructional modules for ten units of instruction (nine-week class): (1) orientation; (2) understanding electricity; (3) safety; (4) methods to generate electricity; (5) wiring tools and wire; (6) soldering; (7) magnetism and electromagnetism; (8)…

Industrial Education. Electricity/Electronics Curriculum Guide, Phase II. Instructional Modules, Level I (18 Week).

ERIC Educational Resources Information Center

Lillo, Robert E.; Soffiotto, Nicholas S.

Designed for students in grades 7 and 8, this electricity/electronics curriculum guide contains instructional modules for twelve units of instruction: (1) orientation; (2) understanding electricity; (3) safety; (4) methods to generate electricity; (5) wiring tools and wire; (6) soldering; (7) magnetism and electromagnetism; (8) circuits, symbols,…