Structural and electrical characteristics of high-k/metal gate metal oxide semiconductor capacitors fabricated on flexible, semi-transparent silicon (100) fabric

KAUST Repository

Rojas, Jhonathan Prieto

2013-02-12

In pursuit of flexible computers with high performance devices, we demonstrate a generic process to fabricate 10 000 metal-oxide-semiconductor capacitors (MOSCAPs) with semiconductor industry\\'s most advanced high-k/metal gate stacks on widely used, inexpensive bulk silicon (100) wafers and then using a combination of iso-/anisotropic etching to release the top portion of the silicon with the already fabricated devices as a mechanically flexible (bending curvature of 133 m−1), optically semi-transparent silicon fabric (1.5 cm × 3 cm × 25 μm). The electrical characteristics show 3.7 nm effective oxide thickness, −0.2 V flat band voltage, and no hysteresis from the fabricated MOSCAPs.

Structural and electrical characteristics of high-k/metal gate metal oxide semiconductor capacitors fabricated on flexible, semi-transparent silicon (100) fabric

KAUST Repository

Rojas, Jhonathan Prieto; Hussain, Muhammad Mustafa; Sevilla, Galo T.

2013-01-01

In pursuit of flexible computers with high performance devices, we demonstrate a generic process to fabricate 10 000 metal-oxide-semiconductor capacitors (MOSCAPs) with semiconductor industry's most advanced high-k/metal gate stacks on widely used, inexpensive bulk silicon (100) wafers and then using a combination of iso-/anisotropic etching to release the top portion of the silicon with the already fabricated devices as a mechanically flexible (bending curvature of 133 m−1), optically semi-transparent silicon fabric (1.5 cm × 3 cm × 25 μm). The electrical characteristics show 3.7 nm effective oxide thickness, −0.2 V flat band voltage, and no hysteresis from the fabricated MOSCAPs.

Flexible high-κ/Metal gate metal/insulator/metal capacitors on silicon (100) fabric

KAUST Repository

Rojas, Jhonathan Prieto

2013-10-01

Implementation of memory on bendable substrates is an important step toward a complete and fully developed notion of mechanically flexible computational systems. In this paper, we have demonstrated a simple fabrication flow to build metal-insulator-metal capacitors, key components of dynamic random access memory, on a mechanically flexible silicon (100) fabric. We rely on standard microfabrication processes to release a thin sheet of bendable silicon (area: 18 {\\ m cm}2 and thickness: 25 \\\\mu{\\ m m}) in an inexpensive and reliable way. On such platform, we fabricated and characterized the devices showing mechanical robustness (minimum bending radius of 10 mm at an applied strain of 83.33% and nominal strain of 0.125%) and consistent electrical behavior regardless of the applied mechanical stress. Furthermore, and for the first time, we performed a reliability study suggesting no significant difference in performance and showing an improvement in lifetime projections. © 1963-2012 IEEE.

Controlled Fabrication of Metallic Electrodes with Atomic Separation

DEFF Research Database (Denmark)

Morpurgo, A.; Robinson, D.; M. Marcus, C.

1998-01-01

We report a new technique for fabricating metallic electrodes on insulating substrates with separations on the 1 nm scale. The fabrication technique, which combines lithographic and electrochemical methods, provides atomic resolution without requiring sophisticated instrumentation. The process is...

Improvements in the fabrication of metallic fuels

International Nuclear Information System (INIS)

Tracy, D.B.; Henslee, S.P.; Dodds, N.E.; Longua, K.J.

1989-01-01

Argonne National Laboratory (ANL) is currently developing a new liquid-metal-cooled breeder reactor known as the Integral Fast Reactor (IFR). The IFR represents the state of the art in metal-fueled reactor technology. Improvements in the fabrication of metal fuel, discussed in this paper, will support ANL-West's (ANL-W) fully remote fuel cycle facility, which is an integral part of the IFR concept

Ordered metal nanotube arrays fabricated by PVD.

Science.gov (United States)

Marquez, F; Morant, C; Campo, T; Sanz, J M; Elizalde, E

2010-02-01

In this work we report a simple method to fabricate ordered arrays of metal nanotubes. This method is based on the deposition of a metal by PVD onto an anodized aluminum oxide (AAO) template. The dimensions of the synthesized nanotubes depend both on the AAO template and on the deposited metal. In fact, it is observed that the aspect ratios of the nanotubes clearly depend significantly on the metal, ranging from 0.6 (Fe) to at least 3 (Zr).

Fabrication of metallic channel-containing UO2 fuels

International Nuclear Information System (INIS)

Yang, Jae Ho; Song, Kun Woo; Kim, Keon Sik; Jung, Youn Ho

2004-01-01

The uranium dioxide is widely used as a fuel material in the nuclear industry, owing to many advantages. But it has a disadvantage of having the lowest thermal conductivity of all kinds of nuclear fuels; metal, carbide, nitride. It is well known that the thermal conductivity of UO 2 fuel is enhanced by making, so called, the CERMET (ceramic-metal) composite which consists of both continuous body of highly thermal-conducting metal and UO 2 islands. The CERMET fuel fabrication technique needs metal phase of at least 30%, mostly more than 50%, of the volume of the pellet in order to keep the metal phase interconnected. This high volume fraction of metal requires such a high enrichment of U that the parasitic effect of metal should be compensated. Therefore, it is attractive to develop an innovative composite fuel that can form continuous metal phase with a small amount of metal. In this investigation, a feasibility study was made on how to make such an innovative fuel. Candidate metals (W, Mo, Cr) were selected, and fabrication process was conceptually designed from thermodynamic calculations. We have experimentally found that a metal phase envelops perfectly UO 2 grains, forming continuous channel throughout the pellet, and improving the thermal conductivity of pellet

Fabrication of Arrays of Metal and Metal Oxide Nanotubes by Shadow Evaporation

NARCIS (Netherlands)

Dickey, Michael D.; Weiss, Emily A.; Smythe, Elizabeth J.; Chiechi, Ryan C.; Capasso, Federico; Whitesides, George M.

2008-01-01

This paper describes a simple technique for fabricating uniform arrays of metal and metal oxide nanotubes with controlled heights and diameters. The technique involves depositing material onto an anodized aluminum oxide (AAO) membrane template using a collimated electron beam evaporation source. The

Indirect Fabrication of Lattice Metals with Thin Sections Using Centrifugal Casting.

Science.gov (United States)

Mun, Jiwon; Ju, Jaehyung; Thurman, James

2016-05-14

One of the typical methods to manufacture 3D lattice metals is the direct-metal additive manufacturing (AM) process such as Selective Laser Melting (SLM) and Electron Beam Melting (EBM). In spite of its potential processing capability, the direct AM method has several disadvantages such as high cost, poor surface finish of final products, limitation in material selection, high thermal stress, and anisotropic properties of parts. We propose a cost-effective method to manufacture 3D lattice metals. The objective of this study is to provide a detailed protocol on fabrication of 3D lattice metals having a complex shape and a thin wall thickness; e.g., octet truss made of Al and Cu alloys having a unit cell length of 5 mm and a cell wall thickness of 0.5 mm. An overall experimental procedure is divided into eight sections: (a) 3D printing of sacrificial patterns (b) melt-out of support materials (c) removal of residue of support materials (d) pattern assembly (e) investment (f) burn-out of sacrificial patterns (g) centrifugal casting (h) post-processing for final products. The suggested indirect AM technique provides the potential to manufacture ultra-lightweight lattice metals; e.g., lattice structures with Al alloys. It appears that the process parameters should be properly controlled depending on materials and lattice geometry, observing the final products of octet truss metals by the indirect AM technique.

Metal nanoparticle direct inkjet printing for low-temperature 3D micro metal structure fabrication

International Nuclear Information System (INIS)

Ko, Seung Hwan; Nam, Koo Hyun; Chung, Jaewon; Hotz, Nico; Grigoropoulos, Costas P

2010-01-01

Inkjet printing of functional materials is a key technology toward ultra-low-cost, large-area electronics. We demonstrate low-temperature 3D micro metal structure fabrication by direct inkjet printing of metal nanoparticles (NPs) as a versatile, direct 3D metal structuring approach representing an alternative to conventional vacuum deposition and photolithographic methods. Metal NP ink was inkjet-printed to exploit the large melting temperature drop of the nanomaterial and the ease of the NP ink formulation. Parametric studies on the basic conditions for stable 3D inkjet printing of NP ink were carried out. Furthermore, diverse 3D metal microstructures, including micro metal pillar arrays, helices, zigzag and micro bridges were demonstrated and electrical characterization was performed. Since the process requires low temperature, it carries substantial potential for fabrication of electronics on a plastic substrate

Photo-Curable Metal-Chelating Coatings Offer a Scalable Approach to Production of Antioxidant Active Packaging.

Science.gov (United States)

Lin, Zhuangsheng; Goddard, Julie

2018-02-01

Synthetic metal chelators (for example, ethylenediaminetetraacetic acid, EDTA) are widely used as additives to control trace transition metal induced oxidation in consumer products. To enable removal of synthetic chelators in response to increasing consumer demand for clean label products, metal-chelating active food packaging technologies have been developed with demonstrated antioxidant efficacy in simulated food systems. However, prior work in fabrication of metal-chelating materials leveraged batch chemical reactions to tether metal-chelating ligands, a process with limited industrial translatability for large-scale fabrication. To improve the industrial translatability, we have designed a 2-step laminated photo-grafting process to introduce metal chelating functionality onto common polymeric packaging materials. Iminodiacetic acid (IDA) functionalized materials were fabricated by photo-grafting poly(acrylic acid) onto polypropylene (PP) films, followed by a second photo-grafting process to graft-polymerize an IDA functionalized vinyl monomer (GMA-IDA). The photo-grafting was conducted under atmospheric conditions and was completed in 2 min. The resulting IDA functionalized metal-chelating material was able to chelate iron and copper, and showed antioxidant efficacy against ascorbic acid degradation, supporting its potential to be used synergistically with natural antioxidants for preservation of food and beverage products. The 2-step photo-grafting process improves the throughput of active packaging coatings, enabling potential roll-to-roll fabrication of metal-chelating active packaging materials for antioxidant food packaging applications. To address consumer and retail demands for "clean label" foods and beverages without a corresponding loss in product quality and shelf life, producers are seeking next generation technologies such as active packaging. In this work, we will report the synthesis of metal-chelating active packaging films, which enable removal

Fabrication of particulate metal fuel for fast burner reactors

International Nuclear Information System (INIS)

Ryu, Ho Jin; Lee, Sun Yong; Kim, Jong Hwan; Woo, Yoon Myung; Ko, Young Mo; Kim, Ki Hwan; Park, Jong Man; Lee, Chan Bok

2012-01-01

U Zr metallic fuel for sodium cooled fast reactors is now being developed by KAERI as a national R and D program of Korea. In order to recycle transuranic elements (TRU) retained in spent nuclear fuel, remote fabrication capability in a shielded hot cell should be prepared. Moreover, generation of long lived radioactive wastes and loss of volatile species should be minimized during the recycled fuel fabrication step. Therefore, innovative fuel concepts should be developed to address the fabrication challenges pertaining to TRU while maintaining good performances of metallic fuel. Particulate fuel concepts have already been proposed and tested at several experimental fast reactor systems and vipac ceramic fuel of RIAR, Russia is one of the examples. However, much less work has been reported for particulate metallic fuel development. Spherical uranium alloy particles with various diameters can be easily produced by the centrifugal atomization technique developed by KAERI. Using the atomized uranium and uranium zirconium alloy particles, we fabricated various kinds of powder pack, powder compacts and sintered pellets. The microstructures and properties of the powder pack and pellets are presented

Fabrication of novel cryomill for synthesis of high purity metallic nanoparticles

Science.gov (United States)

Kumar, Nirmal; Biswas, Krishanu

2015-08-01

The successful preparation of free standing metal nanoparticles with high purity in bulk quantity is the pre-requisite for any potential application. This is possible by using ball milling at cryogenic temperature. However, the most of ball mills available in the market do not allow preparing high purity metal nanoparticles by this route. In addition, it is not possible to carry out in situ measurements of process parameters as well as diagnostic of the process. In the present investigation, we present a detailed study on the fabrication of a cryomill, which is capable of avoiding contaminations in the product. It also provides in situ measurements and diagnostic of the low temperature milling process. Online monitoring of the milling temperature and observation of ball motion are the important aspects in the newly designed mill. The nanoparticles prepared using this fabricated mill have been found to be free standing and also free from contaminations.

Fabrication of metallic microstructures by micromolding nanoparticles

Science.gov (United States)

Morales, Alfredo M.; Winter, Michael R.; Domeier, Linda A.; Allan, Shawn M.; Skala, Dawn M.

2002-01-01

A method is provided for fabricating metallic microstructures, i.e., microcomponents of micron or submicron dimensions. A molding composition is prepared containing an optional binder and nanometer size (1 to 1000 nm in diameter) metallic particles. A mold, such as a lithographically patterned mold, preferably a LIGA or a negative photoresist mold, is filled with the molding composition and compressed. The resulting microstructures are then removed from the mold and the resulting metallic microstructures so provided are then sintered.

Fabrication of metallic fuel for fast breeder reactor

International Nuclear Information System (INIS)

Saify, M.T.; Jha, S.K.; Abdulla, K.K.; Kumar, Arbind; Mittal, R.K.; Prasad, R.S.; Mahule, N.; Kumar, Arun; Prasad, G.J.

2012-01-01

Natural uranium oxide fuelled PHWRs comprises of first stage of Indian nuclear power programme. Liquid metal fast breeder reactors fuelled by Pu (from PHWR's) form the second stage. A shorter reactor doubling time is essential in order to accelerate the nuclear power growth in India. Metallic fuels are known to provide shorter doubling times, necessitating to be used as driver fuel for fast breeder reactors. One of the fabrication routes for metallic fuels having random grain orientation, is injection casting technique. The technique finds its basis in an elementary physical concept - the possibility of supporting a liquid column within a tube, by the application of a pressure difference across the liquid interface inside and outside the tube. At AFD, BARC a facility has been set-up for injection casting of uranium rods in quartz tube moulds, demoulding of cast rods, end-shearing of rods and an automated inspection system for inspection of fuel rods with respect to mass, length, diameter and diameter variation along the length and internal and external porosities/voids. All the above facilities have been set-up in glove boxes and have successfully been used for fabrication of uranium bearing fuel rods. The facility has been designed for fabrication and inspection of Pu-bearing metallic fuels also, if required

Direct fabrication of rigid microstructures on a metallic roller using a dry film resist

International Nuclear Information System (INIS)

Jiang, Liang-Ting; Huang, Tzu-Chien; Chang, Chih-Yuan; Ciou, Jian-Ren; Yang, Sen-Yeu; Huang, Po-Hsun

2008-01-01

This paper presents a novel method to fabricate a metallic roller mold with microstructures on its surface using a dry film resist (DFR). The DFR is laminated uniformly onto the curvy surface of a copper roller. After that, the micro-scale photoresist on the surface of the roller can be patterned by non-planar lithography using a flexible film photomask, followed by ferric chloride wet etching to obtain the desired microstructures. This method overcomes the uniformity issue of photoresist coating on rollers, and solves the molds sliding problem during the embossing process because the microstructures are fabricated directly on the roller surface. Furthermore, the rigid metallic roller mold has excellent strength durability and temperature endurance, which can be used in roller hot embossing with a high embossing pressure. The fabricated microstructure roller mold is used as a mold in the hybrid extrusion roller embossing process and successfully fabricates uniform micro-scale prominent line arrays on PC films. This result proves that the roller fabricated by this method can be successfully used in roller embossing for microstructure mass production. The excellent flatness of dry film resist laminating is the key in this fabrication process. The flexible film photomask can be easily designed using CAD software; this roller fabrication method enhances the design flexibility and reduces the cost and time

On-chip fabrication of alkali-metal vapor cells utilizing an alkali-metal source tablet

International Nuclear Information System (INIS)

Tsujimoto, K; Hirai, Y; Sugano, K; Tsuchiya, T; Tabata, O; Ban, K; Mizutani, N

2013-01-01

We describe a novel on-chip microfabrication technique for the alkali-metal vapor cell of an optically pumped atomic magnetometer (OPAM), utilizing an alkali-metal source tablet (AMST). The newly proposed AMST is a millimeter-sized piece of porous alumina whose considerable surface area holds deposited alkali-metal chloride (KCl) and barium azide (BaN 6 ), source materials that effectively produce alkali-metal vapor at less than 400 °C. Our experiments indicated that the most effective pore size of the AMST is between 60 and 170 µm. The thickness of an insulating glass spacer holding the AMST was designed to confine generated alkali metal to the interior of the vapor cell during its production, and an integrated silicon heater was designed to seal the device using a glass frit, melted at an optimum temperature range of 460–490 °C that was determined by finite element method thermal simulation. The proposed design and AMST were used to successfully fabricate a K cell that was then operated as an OPAM with a measured sensitivity of 50 pT. These results demonstrate that the proposed concept for on-chip microfabrication of alkali-metal vapor cells may lead to effective replacement of conventional glassworking approaches. (paper)

Design and fabrication of metal-insulator-metal diode for high frequency applications

Science.gov (United States)

Azad, Ibrahim; Ram, Manoj K.; Goswami, D. Yogi; Stefanakos, Elias

2017-02-01

Metal-insulator-metal (MIM) diodes play significant role in high speed electronics where high frequency rectification is needed. Quantum based tunneling mechanism helps MIM diodes to rectify at high frequency signals. Rectenna, antenna coupled MIM diodes are becoming popular due to their potential use as IR detectors and energy harvesters. Because of small active area, MIM diodes could easily be incorporated into integrated circuits (IC's). The objective of the work is to design and develop MIM diodes for high frequency rectification. In this work, thin insulating layer of ZnO was fabricated using Langmuir-Blodgett (LB) technique which facilitates ultrathin thin, uniform and pinhole free fabrication of insulating layer. The ZnO layer was synthesized from organic precursor of zinc acetate layer. The optimization in the LB technique of fabrication process led to fabricate MIM diodes with high non-linearity and sensitivity. Moreover, the top and bottom electrodes as well as active area of the diodes were patterned using UV-tunneling conduction mechanism. The highest sensitivity of the diode was measured around 37 (A/W), and the rectification ratio was found around 36 under low applied bias at +/-100 mV.

40 CFR Appendix A to Part 438 - Typical Products in Metal Products and Machinery Sectors

Science.gov (United States)

2010-07-01

... INDUSTRIAL EQUIPMENT Air & Gas Compressors Automatic Vending Machines Ball & Roller Bearings Blowers... Fields, & Services BUS & TRUCK Bus Terminal & Service Facilities Courier Services, Except by Air Freight... Work Bolts, Nuts, Screws, Rivets & Washers Crowns & Closures Cutlery Fabricated Metal Products...

Forging of metallic nano-objects for the fabrication of submicron-size components

International Nuclear Information System (INIS)

Roesler, J; Mukherji, D; Schock, K; Kleindiek, S

2007-01-01

In recent years, nanoscale fabrication has developed considerably, but the fabrication of free-standing nanosize components is still a great challenge. The fabrication of metallic nanocomponents utilizing three basic steps is demonstrated here. First, metallic alloys are used as factories to produce a metallic raw stock of nano-objects/nanoparticles in large numbers. These objects are then isolated from the powder containing thousands of such objects inside a scanning electron microscope using manipulators, and placed on a micro-anvil or a die. Finally, the shape of the individual nano-object is changed by nanoforging using a microhammer. In this way free-standing, high-strength, metallic nano-objects may be shaped into components with dimensions in the 100 nm range. By assembling such nanocomponents, high-performance microsystems can be fabricated, which are truly in the micrometre scale (the size ratio of a system to its component is typically 10:1)

The Metal-Zirconia Implant Fixed Hybrid Full-Arch Prosthesis: An Alternative Technique for Fabrication.

Science.gov (United States)

Stumpel, Lambert J; Haechler, Walter

2018-03-01

The metal-resin hybrid full-arch prosthesis has been a traditionally used type of restoration for full-arch implant fixed dentures. A newer development has centered around the use of monolithic zirconia or zirconia veneered with porcelain. Being a ceramic, zirconia has the potential for fracture. This article describes a technique that utilizes a metal substructure to support a chemically and mechanically resinbonded shell of zirconia. The workflow is discussed, ranging from in-office master cast fabrication to the CAD/ CAM production of the provisional and the definitive metal-zirconia prosthesis. The article also highlights the advantages and disadvantages of various materials used for hybrid prostheses.

Antifungal activity of fabrics knitted by metalized Silver/Polyester composite yarn

Science.gov (United States)

Özkan, İ.; Duru Baykal, P.

2017-10-01

In this study, antifungal properties of fabric knitted from metalized silver/polyester composite yarn were investigated. Intermingling is an alternative technique for yarn blending process. Yarns having different features can be combined by feeding the same intermingling jet. This process is defined as commingling. In the study, intermingling process was used to produce metalized silver/polyester composite yarn. Commingled yarns were knitted to single jersey fabrics by IPM brand sample type circular knitting machine. Antifungal activity test was applied to samples against Aspergillus Niger according to AATCC 30 test procedure. It has been identified that the application provides antifungal activity to fabric.

Investigation of the fabrication parameters of thick film metal oxide-polymer pH electrodes

International Nuclear Information System (INIS)

Gac, Arnaud

2002-01-01

This thesis describes a study into the development of an optimum material and fabrication process for the production of thick film pH electrodes. These devices consist of low cost, miniature and rugged pH sensors formed by screen printing a metal oxide bearing paste onto a high temperature (∼850 deg C) fired metal back contact supported on a standard alumina substrate. The pH sensitive metal oxide layer must be fabricated at relatively low temperatures (<300 deg C) in order to maintain the pH sensitivity of the layer and hence requires the use of a suitably stable low temperature curing binder. Bespoke fabricated inks are derived from a Taguchi style factorial experimental plans in which, different binder types, curing temperatures, hydration level and percentage mixtures of different metal oxides and layer thicknesses were investigated. The pH responses of 18 printed electrodes per batch were assessed in buffer solutions with respect to a commercial reference electrode forming a complete potentiometric circuit. The evaluation criteria used in the study included the device-to-device variation in sensitivity of the pH sensors and their sensitivity variation as a function of time. The results indicated the importance of the choice of binder type in particular on the performance characteristics. Reproducible device-to-device variation in sensitivity was determined for the best inks found, whatever the ink fabrication batch. A reduction in the sensitivity variation with time has been determined using the mathematical models derived from an experimental plan. The lack of reproducibility of the sensitivity magnitude, regardless of the ink manufacturing batch, seems to be a recurrent problem with prototype inks. Experimental sub-Nernstian responses are discussed in the light of possible pH mechanisms. (author)

Fabrication of ultrahigh density metal-cell-metal crossbar memory devices with only two cycles of lithography and dry-etch procedures

KAUST Repository

Zong, Baoyu; Goh, J. Y.; Guo, Zaibing; Luo, Ping; Wang, Chenchen; Qiu, Jinjun; Ho, Pin; Chen, Yunjie; Zhang, Mingsheng; Han, Guchang

2013-01-01

A novel approach to the fabrication of metal-cell-metal trilayer memory devices was demonstrated by using only two cycles of lithography and dry-etch procedures. The fabricated ultrahigh density crossbar devices can be scaled down to ≤70 nm in half

Research on plant of metal fuel fabrication using casting process

International Nuclear Information System (INIS)

Senda, Yasuhide; Mori, Yukihide

2003-12-01

This document presents the plant concept of metal fuel fabrication system (38tHM/y) using casting process in electrolytic recycle, which based on recent studies of its equipment design and quality control system. And we estimate the cost of its construction and operation, including costs of maintenance, consumed hardware and management of waste. The content of this work is as follows. (1) Designing of fuel fabrication equipment: We make material flow diagrams of the fuel fabrication plant and rough designs of the injection casting furnace, demolder and inspection equipment. (2) Designing of resolution system of liquid waste, which comes from analytical process facility. Increased analytical items, we rearrange analytical process facility, estimate its chemicals and amount of waste. (3) Arrangement of equipments: We made a arrangement diagram of the metal fuel fabrication equipments in cells. (4) Estimation of cost data: We estimated cost to construct the facility and to operate it. (author)

Scanning probe lithography for fabrication of Ti metal nanodot arrays

International Nuclear Information System (INIS)

Jung, B.; Jo, W.; Gwon, M.J.; Lee, E.; Kim, D.-W.

2010-01-01

We report fabrication of Ti metal nanodot arrays by scanning probe microscopic indentation. A thin poly-methylmethacrylate (PMMA) layer was spin-coated on Si substrates with thickness of 70 nm. Nanometer-size pore arrays were formed by indenting the PMMA layer using a cantilever of a scanning probe microscope. Protuberances with irregular boundaries appeared during the indentation process. Control of approach and pulling-out speed during indentation was able to dispose of the protrusions. Ti metal films were deposited on the patterned PMMA layers by a radio-frequency sputtering method and subsequently lifted off to obtain metal nanodot arrays. The fabricated metal nanodot arrays have 200 nm of diameter and 500 nm of interdistance, which corresponds to a density of 4x10 8 /cm 2 . Scanning probe-based measurement of current-voltage (I-V) behaviors for a single Ti metal nanodot showed asymmetric characteristics. Applying external bias is likely to induce oxidation of Ti metal, since the conductance decreased and volume change of the dots was observed. I-V behaviors of Ti metal nanodots by conventional e-beam lithography were also characterized for comparison.

Antimicrobial and Thermal Properties of Metal Complexes of Grafted Fabrics with Acrylic Acid by Gamma Irradiation

International Nuclear Information System (INIS)

Hassan, M.S.; Attia, R.M.; Zohdy, M.H.

2008-01-01

Cotton, cotton/PET blend and PET fabrics were treated against microbial effect by radiation - induced grafting of acrylic acid followed by metal complexation with some divalent transition metal ions Co (II), Ni (II) and Cu (II). The microbial resistance was evaluated by testing the mechanical properties of the treated fabrics after burring for one and two weeks in a moist soil reach with microorganisms. Also, the growth of microorganisms was examined by scanning electron microscope (SEM). Moreover, the effect of this treatment on the thermal decomposition behavior was investigated by thermogravimetric analysis (TGA). On the basis of microbial studies, it was found that the metal complexation of the grafted fabrics with acrylic acid enhanced the antimicrobial resistance of the fabrics and the antimicrobial resistance could be arranged according to the metal ions as follows: copper> nickel> cobalt. Also, the thermal stability of different fabrics could be arranged as follow: grafted fabrics complexed with Cu (II) > grafted fabrics complexed with Ni (II) > grafted fabrics complexed with Co (II)

Recent developments in metal and alloy fabrication. Influence on the utilization

International Nuclear Information System (INIS)

1983-01-01

The program of the colloquium includes three parts. In the first part are given developments of metals and alloys elaboration leading to a better productivity, a more precise chemical composition of alloys a greater homogeneity of micro and macrostructure and a decrease of inclusion contents. These improvement in quality are obtained by smelting, refining, ingot solidification and hot working (forging and rolling). The second part shows the consequences of fabrication processes on uses and analyses with more details these improvements by few examples: stainless steels for nuclear industry microalloyed steels, aluminum and titanium alloys. The third part treats chemical analysis to follow the evolution of alloy composition during fabrication and to modify eventually the composition of the melt. New analysis methods are necessary for their adjustment to the nature and the quantity of elements and obtain the required accuracy [fr

Fabrication of BN/Al(-Mg) metal matrix composite (MMC) by pressureless infiltration technique

Energy Technology Data Exchange (ETDEWEB)

Jung, W.G.; Kwon, H. [School of Advanced Materials Eng., Kookmin Univ., Seoul (Korea)

2004-07-01

BN/Al(-Mg) metal matrix composite (MMC) was fabricated by the pressureless infiltration technique. The phase characterizations of the composites were analyzed using the SEM, TEM, EDS and EPMA on reaction products after the electrochemical dissolution of the matrix. It is confirmed that aluminum nitride (AlN) was formed by the reaction of Mg{sub 3}N{sub 2} and Al alloy melt. Plate type AlN and polyhedral type Mg(-Al) boride were formed by the reaction between Mg{sub 3}N{sub 2}, BN and molten Al in the composite. The reaction mechanism in the fabrication of BN/Al(-Mg) MMC was derived from the phase analysis results and the thermodynamic investigation. (orig.)

All-solid-state lithium-ion and lithium metal batteries - paving the way to large-scale production

Science.gov (United States)

Schnell, Joscha; Günther, Till; Knoche, Thomas; Vieider, Christoph; Köhler, Larissa; Just, Alexander; Keller, Marlou; Passerini, Stefano; Reinhart, Gunther

2018-04-01

Challenges and requirements for the large-scale production of all-solid-state lithium-ion and lithium metal batteries are herein evaluated via workshops with experts from renowned research institutes, material suppliers, and automotive manufacturers. Aiming to bridge the gap between materials research and industrial mass production, possible solutions for the production chains of sulfide and oxide based all-solid-state batteries from electrode fabrication to cell assembly and quality control are presented. Based on these findings, a detailed comparison of the production processes for a sulfide based all-solid-state battery with conventional lithium-ion cell production is given, showing that processes for composite electrode fabrication can be adapted with some effort, while the fabrication of the solid electrolyte separator layer and the integration of a lithium metal anode will require completely new processes. This work identifies the major steps towards mass production of all-solid-state batteries, giving insight into promising manufacturing technologies and helping stakeholders, such as machine engineering, cell producers, and original equipment manufacturers, to plan the next steps towards safer batteries with increased storage capacity.

Bacterial contamination of fabric and metal-bead identity card lanyards: A cross-sectional study

Directory of Open Access Journals (Sweden)

Thomas Pepper

2014-11-01

Full Text Available Summary: In healthcare, fabric or metal-bead lanyards are universally used for carrying identity cards. However there is little information on microbial contamination with potential pathogens that may readily re-contaminate disinfected hands. We examined 108 lanyards from hospital staff. Most grew skin flora but 7/108 (6% had potentially pathogenic bacteria: four grew methicillin-susceptible Staphylococcus aureus, and four grew probable fecal flora: 3 Clostridium perfringens and 1 Clostridium bifermentans (one lanyard grew both S. aureus and C. bifermentans. Unused (control lanyards had little or no such contamination. The median duration of lanyard wear was 12 months (interquartile range 3–36 months. 17/108 (16% of the lanyards had reportedly undergone decontamination including wiping with alcohol, chlorhexidine or chlorine dioxide; and washing with soap and water or by washing machine. Metal-bead lanyards had significantly lower median bacterial counts than those from fabric lanyards (1 vs. 4 CFU/cm2; Mann–Whitney U = 300.5; P < 0.001. 12/32 (38% of the metal-bead lanyards grew no bacteria, compared with 2/76 (3% of fabric lanyards. We recommend that an effective decontamination regimen be instituted by those who use fabric lanyards, or that fabric lanyards be discarded altogether in preference for metal-bead lanyards or clip-on identity cards. Keywords: Lanyard, Contamination, Identity card, Metal, Fabric

Antimicrobial and thermal properties of metal complexes of grafted fabrics with acrylic acid by gamma irradiation

International Nuclear Information System (INIS)

Hassan, M.S.; Attia, R.M.; Zohdy, M.H.; Khalil, E.M.

2009-01-01

Cotton, cotton/ ET blend and PET fabrics were treated against microbial effect by radiation -induced grafting of acrylic acid followed by metal complexation with some divalent transition metal ions like Co (l l), Ni(l l) and Cu(l l).The microbial resistance was evaluated by testing the mechanical properties of the treated fabrics after burring for one and two weeks in a moist soil reach with microorganisms. Also, the structural damage of the fabrics caused by biodegradation was examined by scanning electron microscope (SEM). Moreover, the effect of this treatment on the thermal decomposition behaviour was investigated by thermogravimetric analysis (TGA). On the basis of microbial studies, it was found that the metal complexation of the grafted fabrics with acrylic acid enhanced the microbial resistance of the fabrics and the microbial resistance could be arranged according to the complexed metal ions as follows: copper> nickel> cobalt. Also, the thermal stability of different fabrics could be arranged as follow: grafted fabrics complexes with Cu (l l) grafted fabrics complexes with Co (l l)

Stormwater Pollution Prevention Plan for the TA-03-38 Metals Fabrication Shop, Los Alamos National Laboratory, Revision 3, January 2018

Energy Technology Data Exchange (ETDEWEB)

Burgin, Jillian Elizabeth [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2018-02-01

This Storm Water Pollution Prevention Plan (SWPPP) was developed in accordance with the provisions of the Clean Water Act (33 U.S.C. §§1251 et seq., as amended), and the Multi-Sector General Permit for Storm Water Discharges Associated with Industrial Activity (U.S. EPA, June 2015) issued by the U.S. Environmental Protection Agency (EPA) for the National Pollutant Discharge Elimination System (NPDES) and using the industry specific permit requirements for Sector AA-Fabricated Metal Products as a guide. This SWPPP applies to discharges of stormwater from the operational areas of the TA-03-38 Metals Fabrication Shop at Los Alamos National Laboratory. Los Alamos National Laboratory (also referred to as LANL or the “Laboratory”) is owned by the Department of Energy (DOE), and is operated by Los Alamos National Security, LLC (LANS). Throughout this document, the term “facility” refers to the TA-03-38 Metals Fabrication Shop and associated areas. The current permit expires at midnight on June 4, 2020.

Fabrication of ultrahigh density metal-cell-metal crossbar memory devices with only two cycles of lithography and dry-etch procedures

KAUST Repository

Zong, Baoyu

2013-05-20

A novel approach to the fabrication of metal-cell-metal trilayer memory devices was demonstrated by using only two cycles of lithography and dry-etch procedures. The fabricated ultrahigh density crossbar devices can be scaled down to ≤70 nm in half-pitch without alignment issues. Depending on the different dry-etch mechanisms in transferring high and low density nanopatterns, suitable dry-etch angles and methods are studied for the transfer of high density nanopatterns. Some novel process methods have also been developed to eliminate the sidewall and other conversion obstacles for obtaining high density of uniform metallic nanopatterns. With these methods, ultrahigh density trilayer crossbar devices (∼2 × 1010 bit cm-2-kilobit electronic memory), which are composed of built-in practical magnetoresistive nanocells, have been achieved. This scalable process that we have developed provides the relevant industries with a cheap means to commercially fabricate three-dimensional high density metal-cell-metal nanodevices. © 2013 IOP Publishing Ltd.

Measurement of Electromagnetic Shielding Effectiveness of Woven Fabrics Containing Metallic Yarns by Mobile Devices

Directory of Open Access Journals (Sweden)

Erhan Kenan ÇEVEN

2016-10-01

Full Text Available In this study, we introduce an alternative method to evaluate the electromagnetic shielding effectiveness (EMSE of woven fabrics containing metal wires. For experimental measurements, hybrid silk viscose yarns containing metal wires were first produced. Conductive test fabrics were then produced using the hybrid weft yarns and polyester warp yarns. The produced fabrics were separated in two parts and laminated together after rotating one fabric by 90 degrees to create a grid structure. The laminated fabrics were then folded by several times to create multiple layers such as 2,4,8,12,16. The EMSE of the multiple layered fabrics was measured over GSM signals received by a mobile device. For EMSE evaluation, the mobile device was placed between the laminated fabrics. The EMSE values of the fabrics were then calculated in accordance with the power variations of GSM signals.

Engineered Metallic Nanostructures: Fabrication, Characterization, and Applications

Science.gov (United States)

Bohloul, Arash

Metallic nanostructures have garnered a great deal of attention due to their fascinating optical properties, which differ from the bulk metal. They have been proven to exceed expectations in wide variety of applications including chemical and biological sensing. Nevertheless, high-throughput and low cost nanofabrication techniques are required to implant metallic nanostructures in widespread applications. With that vision, this thesis presents a versatile and reliable method for scalable fabrication of gold nanostructures. In this approach, a plasma-treated ordered array of polystyrene nanospheres acts as an initial mask. The key step in this process is the vapor-deposition of nickel as a sacrificial mask. Thereby, gold nanostructures are directly formed on the substrate through the nickel mask. This is an easy, powerful, and straightforward method that offers several degrees of freedom to precisely control the shape and size of nanostructures. We made a library of nanostructures including gold nanocrescents, double crescents, nanorings, and nanodisks with the ability to tune the size in the range of 150 to 650 nm. The fabricated nanostructures are highly packed and uniformly cover the centimeter scale substrate. The optical properties of metallic nanostructures were extensively studied by a combination of UV-Vis-NIR and Fourier transform infrared (FTIR) spectroscopies, and correlation between optical response and geometrical parameters were investigated. In the next part of this thesis, highly sensitive surface enhanced infrared absorption (SEIRA) analysis was demonstrated on gold nanocrescent arrays. Theoretical modeling was confirmed that these substrates provide highly dense and strong hot-spots over the substrate, which is required for surface enhanced spectroscopic studies. Gold nanocrescent arrays exhibit highly tunable plasmon resonance to cover desired molecular vibrational bands. These substrates experimentally illustrated 3 orders of magnitude

Fabrication of large area homogeneous metallic nanostructures for optical sensing using colloidal lithography

DEFF Research Database (Denmark)

Eriksen, René Lynge; Pors, Anders; Dreier, Jes

2010-01-01

We propose a simple and reproducible method for fabricating large area metal films with inter-connected nanostructures using a combination of colloidal lithography, metal deposition and a template stripping technique. The method is generic in the sense that it is possible to produce a variety...... to fabricate metal films with inter-connected nanostructures consisting of either partial spherical shells or the inverted structures: spherical cavities. The substrates are characterized by optical reflectance and transmittance spectroscopy. We demonstrate, in the case of partial spherical shells...

Optimal fabrication processes for unidirectional metal-matrix composites: A computational simulation

Science.gov (United States)

Saravanos, D. A.; Murthy, P. L. N.; Morel, M.

1990-01-01

A method is proposed for optimizing the fabrication process of unidirectional metal matrix composites. The temperature and pressure histories are optimized such that the residual microstresses of the composite at the end of the fabrication process are minimized and the material integrity throughout the process is ensured. The response of the composite during the fabrication is simulated based on a nonlinear micromechanics theory. The optimal fabrication problem is formulated and solved with non-linear programming. Application cases regarding the optimization of the fabrication cool-down phases of unidirectional ultra-high modulus graphite/copper and silicon carbide/titanium composites are presented.

Optimal fabrication processes for unidirectional metal-matrix composites - A computational simulation

Science.gov (United States)

Saravanos, D. A.; Murthy, P. L. N.; Morel, M.

1990-01-01

A method is proposed for optimizing the fabrication process of unidirectional metal matrix composites. The temperature and pressure histories are optimized such that the residual microstresses of the composite at the end of the fabrication process are minimized and the material integrity throughout the process is ensured. The response of the composite during the fabrication is simulated based on a nonlinear micromechanics theory. The optimal fabrication problem is formulated and solved with nonlinear programming. Application cases regarding the optimization of the fabrication cool-down phases of unidirectional ultra-high modulus graphite/copper and silicon carbide/titanium composites are presented.

Direct metal transfer printing on flexible substrate for fabricating optics functional devices

Science.gov (United States)

Jiang, Yingjie; Zhou, Xiaohong; Zhang, Feng; Shi, Zhenwu; Chen, Linsen; Peng, Changsi

2015-11-01

New functional materials and devices based on metal patterns can be widely used in many new and expanding industries,such as flat panel displays, alternative energy,sensors and so on. In this paper, we introduce a new transfer printing method for fabricating metal optics functional devices. This method can directly transfer a metal pattern from a polyethylene terephthalate (PET)supported UV or polydimethylsiloxane (PDMS) pattern to another PET substrate. Purely taking advantage of the anaerobic UV curing adhesive (a-UV) on PET substrate, metal film can be easily peeled off from micro/nano-structured surface. As a result, metal film on the protrusion can be selectively transferred onto the target substrate, to make it the metal functional surface. But which on the bottom can not be transferred. This method provides low cost fabrication of metal thin film devices by avoiding high cost lithography process. Compared with conventional approach, this method can get more smooth rough edges and has wider tolerance range for the original master mold. Future developments and potential applications of this metal transfer method will be addressed.

Accuracy evaluation of metal copings fabricated by computer-aided milling and direct metal laser sintering systems.

Science.gov (United States)

Park, Jong-Kyoung; Lee, Wan-Sun; Kim, Hae-Young; Kim, Woong-Chul; Kim, Ji-Hwan

2015-04-01

To assess the marginal and internal gaps of the copings fabricated by computer-aided milling and direct metal laser sintering (DMLS) systems in comparison to casting method. Ten metal copings were fabricated by casting, computer-aided milling, and DMLS. Seven mesiodistal and labiolingual positions were then measured, and each of these were divided into the categories; marginal gap (MG), cervical gap (CG), axial wall at internal gap (AG), and incisal edge at internal gap (IG). Evaluation was performed by a silicone replica technique. A digital microscope was used for measurement of silicone layer. Statistical analyses included one-way and repeated measure ANOVA to test the difference between the fabrication methods and categories of measured points (α=.05), respectively. The mean gap differed significantly with fabrication methods (P<.001). Casting produced the narrowest gap in each of the four measured positions, whereas CG, AG, and IG proved narrower in computer-aided milling than in DMLS. Thus, with the exception of MG, all positions exhibited a significant difference between computer-aided milling and DMLS (P<.05). Although the gap was found to vary with fabrication methods, the marginal and internal gaps of the copings fabricated by computer-aided milling and DMLS fell within the range of clinical acceptance (<120 µm). However, the statistically significant difference to conventional casting indicates that the gaps in computer-aided milling and DMLS fabricated restorations still need to be further reduced.

Natural uranium metallic fuel elements: fabrication and operating experience

International Nuclear Information System (INIS)

Hammad, F.H.; Abou-Zahra, A.A.; Sharkawy, S.W.

1980-01-01

The main reactor types based on natural uranium metallic fuel element, particularly the early types, are reviewed in this report. The reactor types are: graphite moderated air cooled, graphite moderated gas cooled and heavy water moderated reactors. The design features, fabrication technology of these reactor fuel elements and the operating experience gained during reactor operation are described and discussed. The interrelation between operating experience, fuel design and fabrication was also discussed with emphasis on improving fuel performance. (author)

Criticality safety studies for plutonium–uranium metal fuel pin fabrication facility

International Nuclear Information System (INIS)

Stephen, Neethu Hanna; Reddy, C.P.

2013-01-01

Highlights: ► Criticality safety limits for PUMP-F facility is identified. ► The fissile mass which can be handled safely during alloy preparation is 10.5 kg. ► The number of fuel slugs which can be handled safely during injection casting is 53. ► The number of fuel slugs which can be handled safely after fuel fabrication is 71. - Abstract: This study focuses on the criticality safety during the fabrication of fast reactor metal fuel pins comprising of the fuel type U–15Pu, U–19Pu and U–19Pu–6Zr in the Plutonium–Uranium Metal fuel Pin fabrication Facility (PUMP-F). Maximum amount of fissile mass which can be handled safely during master alloy preparation, Injection casting and fuel slug preparation following fuel pin fabrication were identified and fixed based on this study. In the induction melting furnace, the fissile mass can be limited to 10.5 kg. During fuel slug preparation and fuel pin fabrication, fuel slugs and pins were arranged in hexagonal and square lattices to identify the most reactive configuration. The number of fuel slugs which can be handled safely after injection casting can be fixed to be 53, whereas after fuel fabrication it is 71

Fabrication of Metallic Fuel Slugs for Irradiation Experiments in Fast Breeder Test Reactor

International Nuclear Information System (INIS)

Saify, M.T.; Jha, S.K.; Abdulla, K.K.; Kumar, Arun; Prasad, G.J.

2013-01-01

Advantages of Metallic fuels for future FBR: → High heavy metal atom density; → Higher thermal conductivity at room temperature that increases with temperature; → Metal fuels can be relatively easily fabricated with close dimensional tolerances; → They have excellent compatibility with liquid metal coolants

Fabrication of arrays of metal and metal oxide nanotubes by shadow evaporation.

Science.gov (United States)

Dickey, Michael D; Weiss, Emily A; Smythe, Elizabeth J; Chiechi, Ryan C; Capasso, Federico; Whitesides, George M

2008-04-01

This paper describes a simple technique for fabricating uniform arrays of metal and metal oxide nanotubes with controlled heights and diameters. The technique involves depositing material onto an anodized aluminum oxide (AAO) membrane template using a collimated electron beam evaporation source. The evaporating material enters the porous openings of the AAO membrane and deposits onto the walls of the pores. The membrane is tilted with respect to the column of evaporating material, so the shadows cast by the openings of the pores onto the inside walls of the pores define the geometry of the tubes. Rotation of the membrane during evaporation ensures uniform deposition inside the pores. After evaporation, dissolution of the AAO in base easily removes the template to yield an array of nanotubes connected by a thin backing of the same metal or metal oxide. The diameter of the pores dictates the diameter of the tubes, and the incident angle of evaporation determines the height of the tubes. Tubes up to approximately 1.5 mum in height and 20-200 nm in diameter were fabricated. This method is adaptable to any material that can be vapor-deposited, including indium-tin oxide (ITO), a conductive, transparent material that is useful for many opto-electronic applications. An array of gold nanotubes produced by this technique served as a substrate for surface-enhanced Raman spectroscopy: the Raman signal (per molecule) from a monolayer of benzenethiolate was a factor of approximately 5 x 10(5) greater than that obtained using bulk liquid benzenethiol.

Direct Fabrication of Inkjet-Printed Dielectric Film for Metal-Insulator-Metal Capacitors

Science.gov (United States)

Cho, Cheng-Lin; Kao, Hsuan-ling; Wu, Yung-Hsien; Chang, Li-Chun; Cheng, Chun-Hu

2018-01-01

In this study, an inkjet-printed dielectric film that used a polymer-based SU-8 ink was fabricated for use in a metal-insulator-metal (MIM) capacitor. Thermal treatment of the inkjet-printed SU-8 polymer film affected its surface morphology, chemical structure, and surface wettability. A 20-min soft-bake at 60°C was applied to eliminate inkjet-printed bubbles and ripples. The ultraviolet-exposed SU-8 polymer film was crosslinked at temperatures between 120°C and 220°C and became disordered at 270°C, demonstrated using Fourier-transform infrared spectroscopy. A maximum SU-8 polymer film hard-bake temperature of 120°C was identified, and a printing process was subsequently employed because the appropriate water contact angle of the printed film was 79°. Under the appropriate inkjet printing conditions, the two-transmission-line method was used to extract the dielectric and electrical properties of the SU-8 polymer film, and the electrical behavior of the fabricated MIM capacitor was also characterized.

Improvement of formability for fabricating thin continuously corrugated structures in sheet metal forming process

International Nuclear Information System (INIS)

Choi, Sung Woo; Park, Sang Hu; Park, Seong Hun; Ha, Man Yeong; Jeong, Ho Seung; Cho, Jong Rae

2012-01-01

A stamping process is widely used for fabricating various sheet metal parts for vehicles, airplanes, and electronic devices by the merit of low processing cost and high productivity. Recently, the use of thin sheets with a corrugated structure for sheet metal parts has rapidly increased for use in energy management devices, such as heat exchangers, separators in fuel cells, and many others. However, it is not easy to make thin corrugated structures directly using a single step stamping process due to their geometrical complexity and very thin thickness. To solve this problem, a multi step stamping (MSS) process that includes a heat treatment process to improve formability is proposed in this work: the sequential process is the initial stamping, heat treatment, and final shaping. By the proposed method, we achieved successful results in fabricating thin corrugated structures with an average thickness of 75μm and increased formability of about 31% compared to the single step stamping process. Such structures can be used in a plate-type heat exchanger requiring low weight and a compact shape

Fabrication of Metallic Microneedle by Electroplating and Sharpening of it by Electrochemical Etching

Science.gov (United States)

Huang, Chih-Hao; Tanaka, Takahiro; Takaoki, Yutaka; Izumi, Hayato; Takahashi, Tomokazu; Suzuki, Masato; Aoyagi, Seiji

Aiming at the use in low-invasive medical treatments, this paper reports a fabrication of metallic microneedle, which has a three-dimensionally sharp tip. Compared to a silicon or polymer needle which we previously proposed, a metallic needle has toughness to evade breakage. Even if it is broken, it does not become small pieces thanks to its ductility, which increases the safety for a human body. A nickel needle was fabricated using electroplating, followed by sharpening it by electrochemical etching. A smooth tip surface is obtained due to electrochemical etching reactions. Sharpness and smoothness of the tip are effective for easy insertion in the viewpoint of large stress concentration and small friction, respectively. An experiment of inserting the fabricated needle into an artificial skin of silicone rubber was carried out. The resistance force during insertion was much reduced compared to that of commercial stainless needle (23 G: shank diameter 650 µm). Although a fabricated metallic needle was inserted and pulled-out for several times, it was not broken in any trial. By changing the angle between object surface and needle axis, the insertion experiments were carried out. Fabricated nickel needle was not broken for any angle, while silicon needle was broken in case the angle is small, i.e., the needle is much inclined from normal direction of the surface, which ensures the safety of metallic microneedle to human body in the viewpoint of breakage.

Fabrication of metal-matrix composites and adaptive composites using ultrasonic consolidation process

International Nuclear Information System (INIS)

Kong, C.Y.; Soar, R.C.

2005-01-01

Ultrasonic consolidation (UC) has been used to embed thermally sensitive and damage intolerant fibres within aluminium matrix structures using high frequency, low amplitude, mechanical vibrations. The UC process can induce plastic flow in the metal foils being bonded, to allow the embedding of fibres at typically 25% of the melting temperature of the base metal and at a fraction of the clamping force when compared to fusion processes. To date, the UC process has successfully embedded Sigma silicon carbide (SiC) fibres, shape memory alloy wires and optical fibres, which are presented in this paper. The eventual aim of this research is targeted at the fabrication of adaptive composite structures having the ability to measure external stimuli and respond by adapting their structure accordingly, through the action of embedded active and passive functional fibres within a freeform fabricated metal-matrix structure. This paper presents the fundamental studies of this research to identify embedding methods and working range for the fabrication of adaptive composite structures. The methods considered have produced embedded fibre specimens in which large amounts of plastic flow have been observed, within the matrix, as it is deformed around the fibres, resulting in fully consolidated specimens without damage to the fibres. The microscopic observation techniques and macroscopic functionality tests confirms that the UC process could be applied to the fabrication of metal-matrix composites and adaptive composites, where fusion techniques are not feasible and where a 'cold' process is necessary

A novel fabrication method for surface integration of metal structures into polymers (SIMSIP)

Science.gov (United States)

Carrion-Gonzalez, Hector

Recently developed flexible electronics applications require that the thin metal films embedded on elastomer substrates also be flexible. These electronic systems are radically different in terms of performance and functionality than conventional silicon-based devices. A key question is whether the metal deposited on flexible films can survive large strains without rupture. Cumbersome macro-fabrication methods have been developed for functional and bendable electronics (e.g., interconnects) encapsulated between layers of polymer films. However, future electronic applications may require electronic flexible devices to be in intimate contact with curved surfaces (e.g., retinal implants) and to be robust enough to withstand large and repeated mechanical deformations. In this research, a novel technique for surface integration of metal structures into polymers (SIMSIP) was developed. Surface embedding, as opposed to placing metal on polymers, provides better adherence while leaving the surface accessible for contacts. This was accomplished by first fabricating the micro-scale metal patterns on a quartz or Teflon mother substrate, and then embedding them to a flexible polyimide thin film. The technique was successfully used to embed micro-metal structures of gold (Au), silver (Ag), and copper (Cu) into polyimide films without affecting the functional properties of the either the metals or the polymers. Experimental results confirm the successful surface-embedding of metal structures as narrow as 0.6 microm wide for different geometries commonly used in circuit design. Although similar approaches exist in literature, the proposed methodology provides a simpler and more reliable way of producing flexible circuits/electronics that is also suitable for high volume manufacturing. In order to demonstrate the flexibility of metal interconnects fabricated using the SIMSIP technique, multiple Au electrodes (5 microm and 2.5 microm wide) were tested using the X-theta bending

Three-dimensional metallic opals fabricated by double templating

International Nuclear Information System (INIS)

Yan Qingfeng; Nukala, Pavan; Chiang, Yet-Ming; Wong, C.C.

2009-01-01

We report a simple and cost-effective double templating method for fabricating large-area three-dimensional metallic photonic crystals of controlled thickness. A self-assembled polystyrene opal was used as the first template to fabricate a silica inverse opal on a gold-coated glass substrate via sol-gel processing. Gold was subsequently infiltrated to the pores of the silica inverse opal using electrochemical deposition. A high-quality three-dimensional gold photonic crystal was obtained after removal of the secondary template (silica inverse opal). The effects of template sphere size and deposition current density on the gold growth rate, and the resulting morphology and growth mechanism of the gold opal, were investigated.

Stacking metal nano-patterns and fabrication of moth-eye structure

Science.gov (United States)

Taniguchi, Jun

2018-01-01

Nanoimprint lithography (NIL) can be used as a tool for three-dimensional nanoscale fabrication. In particular, complex metal pattern structures in polymer material are demanded as plasmonic effect devices and metamaterials. To fabricate of metallic color filter, we used silver ink and NIL techniques. Metallic color filter was composed of stacking of nanoscale silver disc patterns and polymer layers, thus, controlling of polymer layer thickness is necessary. To control of thickness of polymer layer, we used spin-coating of UV-curable polymer and NIL. As a result, ten stacking layers with 1000 nm layer thickness was obtained and red color was observed. Ultraviolet nanoimprint lithography (UV-NIL) is the most effective technique for mass fabrication of antireflection structure (ARS) films. For the use of ARS films in mobile phones and tablet PCs, which are touch-screen devices, it is important to protect the films from fingerprints and dust. In addition, as the nanoscale ARS that is touched by the hand is fragile, it is very important to obtain a high abrasion resistance. To solve these problems, a UV-curable epoxy resin has been developed that exhibits antifouling properties and high hardness. The high abrasion resistance ARS films are shown to withstand a load of 250 g/cm2 in the steel wool scratch test, and the reflectance is less than 0.4%.

The flashcal process for the fabrication of fuel-metal oxides using the whiteshell roto-spray calciner

International Nuclear Information System (INIS)

Sridhar, T.S.

1988-01-01

A one-step, continuous, thermochemical calcination process, called the FLASHCAL (Flash Calcination) process has been developed for the production of single- and mixed-oxide powders of fuel metals (uranium, thorium and plutonium) from the respective nitrate solutions using the Whiteshell Roto-Spray Calciner (RSC). The metal-nitrate feed solution, either by itself or mixed with a suitable chemical reactant or additive, is converted to its oxide powder in the RSC at temperatures between 300 and 600 0 C. Rapid denitration takes place in the calciner, yielding the metal-oxide powders while simultaneously destroying any excess chemical additive and reaction by-products. In the production of precursor oxide powders suitable for fuel fabrication, the FLASHCAL process has advantages over batch calcination and other processes that involve precipitation and filtration steps because fewer processing and handling operations are needed. Results obtained with thorium nitrate and uranium nitrate-thorium nitrate mixtures indicate that some measure of control over the size distribution and morphology of the oxide product powders is possible in this process with the proper selection of chemical additive, as well as the operating parameters of the calciner

Fabrication and modification of metal nanocluster composites using ion and laser beams

International Nuclear Information System (INIS)

Haglund, R.F. Jr.; Osborne, D.H. Jr.; Magruder, R.H. III; White, C.W.; Zuhr, R.A.; Townsend, P.D.; Hole, D.E.; Leuchtner, R.E.

1994-12-01

Metal nanocluster composites have attractive properties for applications in nonlinear optics. However, traditional fabrication techniques -- using melt-glass substrates -- are severely constrained by equilibrium thermodynamics and kinetics. This paper describes the fabrication of metal nanoclusters in both crystalline and glassy hosts by ion implantation and pulsed laser deposition. The size and size distribution of the metal nanoclusters can be modified by controlling substrate temperature during implantation, by subsequent thermal annealing, or by laser irradiation. The authors have characterized the optical response of the composites by absorption and third-order nonlinear-optical spectroscopies; electron and scanning-probe microscopies have been used to benchmark the physical characteristics of the composites. The outlook for controlling the structure and nonlinear optical response properties of these nanophase materials appears increasingly promising

Flexible semi-transparent silicon (100) fabric with high-k/metal gate devices

KAUST Repository

Rojas, Jhonathan Prieto

2013-01-07

Can we build a flexible and transparent truly high performance computer? High-k/metal gate stack based metal-oxide-semiconductor capacitor devices are monolithically fabricated on industry\\'s most widely used low-cost bulk single-crystalline silicon (100) wafers and then released as continuous, mechanically flexible, optically semi-transparent and high thermal budget compatible silicon fabric with devices. This is the first ever demonstration with this set of materials which allows full degree of freedom to fabricate nanoelectronics devices using state-of-the-art CMOS compatible processes and then to utilize them in an unprecedented way for wide deployment over nearly any kind of shape and architecture surfaces. Electrical characterization shows uncompromising performance of post release devices. Mechanical characterization shows extra-ordinary flexibility (minimum bending radius of 1 cm) making this generic process attractive to extend the horizon of flexible electronics for truly high performance computers. Schematic and photograph of flexible high-k/metal gate MOSCAPs showing high flexibility and C-V plot showing uncompromised performance. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Trial fabrication and preliminary characterization of electrical insulator for liquid metal system

International Nuclear Information System (INIS)

Nakamichi, Masaru; Kawamura, Hiroshi; Oyamada, Rokuro

1995-03-01

In the design of the liquid metal blanket, MHD pressure drop is one of critical issues. Ceramic coating on the surface of structural material is considered as an electrical insulator to reduce the MHD pressure drop. Ceramic coating such as Y 2 O 3 is a promising electrical insulator due to its high electrical resistivity and good compatibility with liquid lithium. This report describes the trial fabrication and preliminary characterization of electrical insulator for a design study of the liquid metal system. From the results of trial fabrication and preliminary characterization, it is concluded that densified atmospheric plasma spray Y 2 O 3 coating with 410SS undercoating between 316SS substrate and Y 2 O 3 coating is suitable for Y 2 O 3 coating fabrication. (author)

Fabrication of sub-micrometric metallic hollow-core structures by laser interference lithography

International Nuclear Information System (INIS)

Pérez, Noemí; Tavera, Txaber; Rodríguez, Ainara; Ellman, Miguel; Ayerdi, Isabel; Olaizola, Santiago M.

2012-01-01

Highlights: ► Arrays of hollow-core sub-micrometric structures are fabricated. ► Laser interference lithography is used for the pattering of the resist sacrificial layer. ► The removal of the sacrificial layer gives rise to metallic channels with a maximum crosssectional area of 0.1 μm 2 . ► These structures can be used in nanofluidics. - Abstract: This work presents the fabrication of hollow-core metallic structures with a complete laser interference lithography (LIL) process. A negative photoresist is used as sacrificial layer. It is exposed to the pattern resulting from the interference of two laser beams, which produces a structure of photoresist lines with a period of 600 nm. After development of the resist, platinum is deposited on the samples by DC sputtering and the resist is removed with acetone. The resulting metallic structures consist in a continuous platinum film that replicates the photoresist relief with a hollow core. The cross section of the channels is up to 0.1 μm 2 . The fabricated samples are characterized by FESEM and FIB. This last tool helps to provide a clear picture of the shape and size of the channels. Conveniently dimensioned, this array of metallic submicrometric channels can be used in microfluidic or IC cooling applications.

Thermal and mechanical properties of aluminized fabrics for use in ferrous metal handling operations.

Science.gov (United States)

Wren, J E; Scott, W D; Bates, C E

1977-11-01

Protective garments are normally worn in molten handling operations to provide some protection against molten metal splashes. These garments are also intended to provide protection against radiant heat, and they should be as heat resistant and comfortable as possible. Asbestos-based fabrics have been employed for many years, but recently some concern has been expressed over possible asbestos exposure. This program was undertaken to explore the ability of several types of fabrics to resist heat transfer during molten metal impact. A molten metal splash test, along with standard methods for determining tensile strength, flame resistance, and abrasion-flexing resistance were used to evaluate several classes of protective fabrics. The results indicate that there are materials available that offer equal or better mechanical properties and thermal protection compared to aluminized asbestos.

Metallic dielectric photonic crystals and methods of fabrication

Energy Technology Data Exchange (ETDEWEB)

Chou, Jeffrey Brian; Kim, Sang-Gook

2016-12-20

A metallic-dielectric photonic crystal is formed with a periodic structure defining a plurality of resonant cavities to selectively absorb incident radiation. A metal layer is deposited on the inner surfaces of the resonant cavities and a dielectric material fills inside the resonant cavities. This photonic crystal can be used to selectively absorb broadband solar radiation and then reemit absorbed radiation in a wavelength band that matches the absorption band of a photovoltaic cell. The photonic crystal can be fabricated by patterning a sacrificial layer with a plurality of holes, into which is deposited a supporting material. Removing the rest of the sacrificial layer creates a supporting structure, on which a layer of metal is deposited to define resonant cavities. A dielectric material then fills the cavities to form the photonic crystal.

Metallic dielectric photonic crystals and methods of fabrication

Energy Technology Data Exchange (ETDEWEB)

Chou, Jeffrey Brian; Kim, Sang-Gook

2017-12-05

A metallic-dielectric photonic crystal is formed with a periodic structure defining a plurality of resonant cavities to selectively absorb incident radiation. A metal layer is deposited on the inner surfaces of the resonant cavities and a dielectric material fills inside the resonant cavities. This photonic crystal can be used to selectively absorb broadband solar radiation and then reemit absorbed radiation in a wavelength band that matches the absorption band of a photovoltaic cell. The photonic crystal can be fabricated by patterning a sacrificial layer with a plurality of holes, into which is deposited a supporting material. Removing the rest of the sacrificial layer creates a supporting structure, on which a layer of metal is deposited to define resonant cavities. A dielectric material then fills the cavities to form the photonic crystal.

The fabrication of metal silicide nanodot arrays using localized ion implantation

International Nuclear Information System (INIS)

Han, Jin; Kim, Tae-Gon; Min, Byung-Kwon; Lee, Sang Jo

2010-01-01

We propose a process for fabricating nanodot arrays with a pitch size of less than 25 nm. The process consists of localized ion implantation in a metal thin film on a Si wafer using a focused ion beam (FIB), followed by chemical etching. This process utilizes the etching resistivity changes of the ion beam irradiated region that result from metal silicide formation by ion implantation. To control the nanodot diameter, a threshold ion dose model is proposed using the Gaussian distribution of the ion beam intensities. The process is verified by fabricating nanodots with various diameters. The mechanism of etching resistivity is investigated via x-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES).

Super Lightweight, Metal Rubber Fabric for Extreme Space Environments, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — NanoSonic has fabricated revolutionary nanostructured, yet macroscale, multifunctional Metal RubberTM films via layer-by-layer, molecular self-assembly, which...

Fabrication and properties of gallium metallic photonic crystals

International Nuclear Information System (INIS)

Kozhevnikov, V.F.; Diwekar, M.; Kamaev, V.P.; Shi, J.; Vardeny, Z.V.

2003-01-01

Gallium metallic photonic crystals with 100% filling factor have been fabricated via infiltration of liquid gallium into opals of 300-nm silica spheres using a novel high pressure-high temperature technique. The electrical resistance of the Ga-opal crystals was measured at temperatures from 10 to 280 K. The data obtained show that Ga-opal crystals are metallic network with slightly smaller temperature coefficient of resistivity than that for bulk gallium. Optical reflectivity of bulk gallium, plain opal and several Ga-opal crystals were measured at photon energies from 0.3 to 6 eV. A pronounced photonic stop band in the visible spectral range was found in both the plain and Ga infiltrated opals. The reflectivity spectra also show increase in reflectivity below 0.6 eV; which we interpret as a significantly lower effective plasma frequency of the metallic mesh in the infiltrated opal compare to the plasma frequency in the pure metal

16 CFR 303.24 - Pile fabrics and products composed thereof.

Science.gov (United States)

2010-01-01

... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Pile fabrics and products composed thereof... CONGRESS RULES AND REGULATIONS UNDER THE TEXTILE FIBER PRODUCTS IDENTIFICATION ACT § 303.24 Pile fabrics and products composed thereof. The fiber content of pile fabrics or products composed thereof may be...

Design and characterization of a fully differential MEMS accelerometer fabricated using MetalMUMPs technology.

Science.gov (United States)

Qu, Peng; Qu, Hongwei

2013-05-02

This paper presents a fully differential single-axis accelerometer fabricated using the MetalMUMPs process. The unique structural configuration and common-centriod wiring of the metal electrodes enables a fully differential sensing scheme with robust metal sensing structures. CoventorWare is used in structural and electrical design and simulation of the fully differential accelerometer. The MUMPs foundry fabrication process of the sensor allows for high yield, good process consistency and provides 20 μm structural thickness of the sensing element, which makes the capacitive sensing eligible. In device characterization, surface profile of the fabricated device is measured using a Veeco surface profilometer; and mean and gradient residual stress in the nickel structure are calculated as approximately 94.7 MPa and -5.27 MPa/μm, respectively. Dynamic characterization of the sensor is performed using a vibration shaker with a high-end commercial calibrating accelerometer as reference. The sensitivity of the sensor is measured as 0.52 mV/g prior to off-chip amplification. Temperature dependence of the sensing capacitance is also characterized. A -0.021fF/°C is observed. The findings in the presented work will provide useful information for design of sensors and actuators such as accelerometers, gyroscopes and electrothermal actuators that are to be fabricated using MetalMUMPs technology.

Metal-ceramic bond strength between a feldspathic porcelain and a Co-Cr alloy fabricated with Direct Metal Laser Sintering technique.

Science.gov (United States)

Dimitriadis, Konstantinos; Spyropoulos, Konstantinos; Papadopoulos, Triantafillos

2018-02-01

The aim of the present study was to record the metal-ceramic bond strength of a feldspathic dental porcelain and a Co-Cr alloy, using the Direct Metal Laser Sintering technique (DMLS) for the fabrication of metal substrates. Ten metal substrates were fabricated with powder of a dental Co-Cr alloy using DMLS technique (test group) in dimensions according to ISO 9693. Another ten substrates were fabricated with a casing dental Co-Cr alloy using classic casting technique (control group) for comparison. Another three substrates were fabricated using each technique to record the Modulus of Elasticity ( E ) of the used alloys. All substrates were examined to record external and internal porosity. Feldspathic porcelain was applied on the substrates. Specimens were tested using the three-point bending test. The failure mode was determined using optical and scanning electron microscopy. The statistical analysis was performed using t-test. Substrates prepared using DMLS technique did not show internal porosity as compared to those produced using the casting technique. The E of control and test group was 222 ± 5.13 GPa and 227 ± 3 GPa, respectively. The bond strength was 51.87 ± 7.50 MPa for test group and 54.60 ± 6.20 MPa for control group. No statistically significant differences between the two groups were recorded. The mode of failure was mainly cohesive for all specimens. Specimens produced by the DMLS technique cover the lowest acceptable metal-ceramic bond strength of 25 MPa specified in ISO 9693 and present satisfactory bond strength for clinical use.

Characterization and fabrication of fully metal-coated scanning near-field optical microscopy SiO2 tips.

Science.gov (United States)

Aeschimann, L; Akiyama, T; Staufer, U; De Rooij, N F; Thiery, L; Eckert, R; Heinzelmann, H

2003-03-01

The fabrication of silicon cantilever-based scanning near-field optical microscope probes with fully aluminium-coated quartz tips was optimized to increase production yield. Different cantilever designs for dynamic- and contact-mode force feedback were implemented. Light transmission through the tips was investigated experimentally in terms of the metal coating and the tip cone-angle. We found that transmittance varies with the skin depth of the metal coating and is inverse to the cone angle, meaning that slender tips showed higher transmission. Near-field optical images of individual fluorescing molecules showed a resolution thermocouple showed no evidence of mechanical defect or orifice formation by thermal effects.

16 CFR 300.26 - Pile fabrics and products composed thereof.

Science.gov (United States)

2010-01-01

... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Pile fabrics and products composed thereof... CONGRESS RULES AND REGULATIONS UNDER THE WOOL PRODUCTS LABELING ACT OF 1939 Labeling § 300.26 Pile fabrics and products composed thereof. The fiber content of pile fabrics or products made thereof may be...

Processing and Electromagnetic Shielding Properties of Multifunctional Metal Composite Knitted Fabric used as Socks

Directory of Open Access Journals (Sweden)

Yu Zhicai

2016-01-01

Full Text Available In this research, a type of bamboo charcoal polyester (BC-PET/antibacterial nylon(AN/stainless steel wire (SSW metal composite yarn was prepared with a hollow spindle spinning machine, which using the SSW as the core material, the BC-PET and AN as the outer and inner wrapped yarns, respectively. The wrapping numbers was set at 8.0turns/cm for the produced metal composite yarns. Furthermore, a type of plated knitted fabric was designed and produced by using the automatic jacquard knitting machine. The plated knitted fabric presents the BC-PET/AN/SSW metal composite yarn on the knitted fabric face and the crisscross-section polyester (CSP on the knit back. The effect of lamination numbers and angles on the electromagnetic shielding effectiveness (EMSE were discussed in this study. EMSE measurement showed that the lamination angles will influence the EMSE, but not affect the air permeability. Finally, a novel EM shielding socks was designed with the produced plated knitted fabric. Finally, the performance of thermal resistance and evaporation resistance was also test usingThe sweating guarded hot plate apparatus.

Fabrication of Superhydrophobic Metallic Surface by Wire Electrical Discharge Machining for Seamless Roll-to-Roll Printing

Directory of Open Access Journals (Sweden)

Jin-Young So

2018-04-01

Full Text Available This paper presents a proposal of a direct one-step method to fabricate a multi-scale superhydrophobic metallic seamless roll mold. The mold was fabricated using the wire electrical discharge machining (WEDM technique for a roll-to-roll imprinting application to produce a large superhydrophobic surface. Taking advantage of the exfoliating characteristic of the metallic surface, nano-sized surface roughness was spontaneously formed while manufacturing the micro-sized structure: that is, a dual-scale hierarchical structure was easily produced in a simple one-step fabrication with a large area on the aluminum metal surface. This hierarchical structure showed superhydrophobicity without chemical coating. A roll-type seamless mold for the roll-to-roll process was fabricated through engraving the patterns on the cylindrical substrate, thereby enabling to make a continuous film with superhydrophobicity.

Process for the fabrication of aluminum metallized pyrolytic graphite sputtering targets

Science.gov (United States)

Makowiecki, Daniel M.; Ramsey, Philip B.; Juntz, Robert S.

1995-01-01

An improved method for fabricating pyrolytic graphite sputtering targets with superior heat transfer ability, longer life, and maximum energy transmission. Anisotropic pyrolytic graphite is contoured and/or segmented to match the erosion profile of the sputter target and then oriented such that the graphite's high thermal conductivity planes are in maximum contact with a thermally conductive metal backing. The graphite contact surface is metallized, using high rate physical vapor deposition (HRPVD), with an aluminum coating and the thermally conductive metal backing is joined to the metallized graphite target by one of four low-temperature bonding methods; liquid-metal casting, powder metallurgy compaction, eutectic brazing, and laser welding.

Development of uranium metal targets for 99Mo production

International Nuclear Information System (INIS)

Wiencek, T.C.; Hofman, G.L.

1993-10-01

A substantial amount of high enriched uranium (HEU) is used for the production of medical-grade 99 Mo. Promising methods of producing irradiation targets are being developed and may lead to the reduction or elimination of this HEU use. To substitute low enriched uranium (LEU) for HEU in the production of 99 Mo, the target material may be changed to uranium metal foil. Methods of fabrication are being developed to simplify assembly and disassembly of the targets. Removal of the uranium foil after irradiation without dissolution of the cladding is a primary goal in order to reduce the amount of liquid radioactive waste material produced in the process. Proof-of-concept targets have been fabricated. Destructive testing indicates that acceptable contact between the uranium foil and the cladding can be achieved. Thermal annealing tests, which simulate the cladding/uranium diffusion conditions during irradiation, are underway. Plans are being made to irradiate test targets

Fabrication of sub-micrometric metallic hollow-core structures by laser interference lithography

Energy Technology Data Exchange (ETDEWEB)

Perez, Noemi; Tavera, Txaber [CEIT and Tecnun (University of Navarra) Manuel de Lardizabal 15, 20018 San Sebastian (Spain); Rodriguez, Ainara [CIC Microgune, Paseo Mikeletegi 48, 20009 San Sebastian (Spain); Ellman, Miguel; Ayerdi, Isabel; Olaizola, Santiago M. [CEIT and Tecnun (University of Navarra) Manuel de Lardizabal 15, 20018 San Sebastian (Spain)

2012-09-15

Highlights: Black-Right-Pointing-Pointer Arrays of hollow-core sub-micrometric structures are fabricated. Black-Right-Pointing-Pointer Laser interference lithography is used for the pattering of the resist sacrificial layer. Black-Right-Pointing-Pointer The removal of the sacrificial layer gives rise to metallic channels with a maximum crosssectional area of 0.1 {mu}m{sup 2}. Black-Right-Pointing-Pointer These structures can be used in nanofluidics. - Abstract: This work presents the fabrication of hollow-core metallic structures with a complete laser interference lithography (LIL) process. A negative photoresist is used as sacrificial layer. It is exposed to the pattern resulting from the interference of two laser beams, which produces a structure of photoresist lines with a period of 600 nm. After development of the resist, platinum is deposited on the samples by DC sputtering and the resist is removed with acetone. The resulting metallic structures consist in a continuous platinum film that replicates the photoresist relief with a hollow core. The cross section of the channels is up to 0.1 {mu}m{sup 2}. The fabricated samples are characterized by FESEM and FIB. This last tool helps to provide a clear picture of the shape and size of the channels. Conveniently dimensioned, this array of metallic submicrometric channels can be used in microfluidic or IC cooling applications.

Mass production compatible fabrication techniques of single-crystalline silver metamaterials and plasmonics devices

Science.gov (United States)

Rodionov, Ilya A.; Baburin, Alexander S.; Zverev, Alexander V.; Philippov, Ivan A.; Gabidulin, Aidar R.; Dobronosova, Alina A.; Ryzhova, Elena V.; Vinogradov, Alexey P.; Ivanov, Anton I.; Maklakov, Sergey S.; Baryshev, Alexander V.; Trofimov, Igor V.; Merzlikin, Alexander M.; Orlikovsky, Nikolay A.; Rizhikov, Ilya A.

2017-08-01

During last 20 years, great results in metamaterials and plasmonic nanostructures fabrication were obtained. However, large ohmic losses in metals and mass production compatibility still represent the most serious challenge that obstruct progress in the fields of metamaterials and plasmonics. Many recent research are primarily focused on developing low-loss alternative materials, such as nitrides, II-VI semiconductor oxides, high-doped semiconductors, or two-dimensional materials. In this work, we demonstrate that our perfectly fabricated silver films can be an effective low-loss material system, as theoretically well-known. We present a fabrication technology of plasmonic and metamaterial nanodevices on transparent (quartz, mica) and non-transparent (silicon) substrates by means of e-beam lithography and ICP dry etch instead of a commonly-used focused ion beam (FIB) technology. We eliminate negative influence of litho-etch steps on silver films quality and fabricate square millimeter area devices with different topologies and perfect sub-100 nm dimensions reproducibility. Our silver non-damage fabrication scheme is tested on trial manufacture of spasers, plasmonic sensors and waveguides, metasurfaces, etc. These results can be used as a flexible device manufacture platform for a broad range of practical applications in optoelectronics, communications, photovoltaics and biotechnology.

Systems and Methods for Fabricating Structures Including Metallic Glass-Based Materials Using Low Pressure Casting

Science.gov (United States)

Hofmann, Douglas C. (Inventor); Kennett, Andrew (Inventor)

2018-01-01

Systems and methods to fabricate objects including metallic glass-based materials using low-pressure casting techniques are described. In one embodiment, a method of fabricating an object that includes a metallic glass-based material includes: introducing molten alloy into a mold cavity defined by a mold using a low enough pressure such that the molten alloy does not conform to features of the mold cavity that are smaller than 100 microns; and cooling the molten alloy such that it solidifies, the solid including a metallic glass-based material.

Design and Characterization of a Fully Differential MEMS Accelerometer Fabricated Using MetalMUMPs Technology

Directory of Open Access Journals (Sweden)

Hongwei Qu

2013-05-01

Full Text Available This paper presents a fully differential single-axis accelerometer fabricated using the MetalMUMPs process. The unique structural configuration and common-centriod wiring of the metal electrodes enables a fully differential sensing scheme with robust metal sensing structures. CoventorWare is used in structural and electrical design and simulation of the fully differential accelerometer. The MUMPs foundry fabrication process of the sensor allows for high yield, good process consistency and provides 20 μm structural thickness of the sensing element, which makes the capacitive sensing eligible. In device characterization, surface profile of the fabricated device is measured using a Veeco surface profilometer; and mean and gradient residual stress in the nickel structure are calculated as approximately 94.7 MPa and −5.27 MPa/μm, respectively. Dynamic characterization of the sensor is performed using a vibration shaker with a high-end commercial calibrating accelerometer as reference. The sensitivity of the sensor is measured as 0.52 mV/g prior to off-chip amplification. Temperature dependence of the sensing capacitance is also characterized. A −0.021fF/°C is observed. The findings in the presented work will provide useful information for design of sensors and actuators such as accelerometers, gyroscopes and electrothermal actuators that are to be fabricated using MetalMUMPs technology.

Layerless fabrication with continuous liquid interface production.

Science.gov (United States)

Janusziewicz, Rima; Tumbleston, John R; Quintanilla, Adam L; Mecham, Sue J; DeSimone, Joseph M

2016-10-18

Despite the increasing popularity of 3D printing, also known as additive manufacturing (AM), the technique has not developed beyond the realm of rapid prototyping. This confinement of the field can be attributed to the inherent flaws of layer-by-layer printing and, in particular, anisotropic mechanical properties that depend on print direction, visible by the staircasing surface finish effect. Continuous liquid interface production (CLIP) is an alternative approach to AM that capitalizes on the fundamental principle of oxygen-inhibited photopolymerization to generate a continual liquid interface of uncured resin between the growing part and the exposure window. This interface eliminates the necessity of an iterative layer-by-layer process, allowing for continuous production. Herein we report the advantages of continuous production, specifically the fabrication of layerless parts. These advantages enable the fabrication of large overhangs without the use of supports, reduction of the staircasing effect without compromising fabrication time, and isotropic mechanical properties. Combined, these advantages result in multiple indicators of layerless and monolithic fabrication using CLIP technology.

Superconducting materials fabrication process and products obtained. Procede de fabrication de materiaux supraconducteurs et produits ainsi obtenus

Energy Technology Data Exchange (ETDEWEB)

Dubois, B; Odier, P

1989-09-15

A fabrication process of a fine superconducting powder easy to sinter is claimed. It consists in thermal treatment of an aerosol containing an organic and/or inorganic salt and/or a hydroxide of a rare earth, an alkaline earth metal and a transition metal in a ratio corresponding to the stoichiometry of the superconducting materials.

A top-down approach for fabricating three-dimensional closed hollow nanostructures with permeable thin metal walls

Directory of Open Access Journals (Sweden)

Carlos Angulo Barrios

2017-06-01

Full Text Available We report on a top-down method for the controlled fabrication of three-dimensional (3D, closed, thin-shelled, hollow nanostructures (nanocages on planar supports. The presented approach is based on conventional microelectronic fabrication processes and exploits the permeability of thin metal films to hollow-out polymer-filled metal nanocages through an oxygen-plasma process. The technique is used for fabricating arrays of cylindrical nanocages made of thin Al shells on silicon substrates. This hollow metal configuration features optical resonance as revealed by spectral reflectance measurements and numerical simulations. The fabricated nanocages were demonstrated as a refractometric sensor with a measured bulk sensitivity of 327 nm/refractive index unit (RIU. The pattern design flexibility and controllability offered by top-down nanofabrication techniques opens the door to the possibility of massive integration of these hollow 3D nano-objects on a chip for applications such as nanocontainers, nanoreactors, nanofluidics, nano-biosensors and photonic devices.

A top-down approach for fabricating three-dimensional closed hollow nanostructures with permeable thin metal walls.

Science.gov (United States)

Barrios, Carlos Angulo; Canalejas-Tejero, Víctor

2017-01-01

We report on a top-down method for the controlled fabrication of three-dimensional (3D), closed, thin-shelled, hollow nanostructures (nanocages) on planar supports. The presented approach is based on conventional microelectronic fabrication processes and exploits the permeability of thin metal films to hollow-out polymer-filled metal nanocages through an oxygen-plasma process. The technique is used for fabricating arrays of cylindrical nanocages made of thin Al shells on silicon substrates. This hollow metal configuration features optical resonance as revealed by spectral reflectance measurements and numerical simulations. The fabricated nanocages were demonstrated as a refractometric sensor with a measured bulk sensitivity of 327 nm/refractive index unit (RIU). The pattern design flexibility and controllability offered by top-down nanofabrication techniques opens the door to the possibility of massive integration of these hollow 3D nano-objects on a chip for applications such as nanocontainers, nanoreactors, nanofluidics, nano-biosensors and photonic devices.

Silica needle template fabrication of metal hollow microneedle arrays

International Nuclear Information System (INIS)

Zhu, M W; Li, H W; Chen, X L; Tang, Y F; Lu, M H; Chen, Y F

2009-01-01

Drug delivery through hollow microneedle (HMN) arrays has now been recognized as one of the most promising techniques because it minimizes the shortcomings of the traditional drug delivery methods and has many exciting advantages—pain free and tunable release rates, for example. However, this drug delivery method has been hindered greatly from mass clinical application because of the high fabrication cost of HMN arrays. Hence, we developed a simple and cost-effective procedure using silica needles as templates to massively fabricate HMN arrays by using popular materials and industrially applicable processes of micro- imprint, hot embossing, electroplating and polishing. Metal HMN arrays with high quality are prepared with great flexibility with tunable parameters of area, length of needle, size of hollow and array dimension. This efficient and cost-effective fabrication method can also be applied to other applications after minor alterations, such as preparation of optic, acoustic and solar harvesting materials and devices

Silica needle template fabrication of metal hollow microneedle arrays

Science.gov (United States)

Zhu, M. W.; Li, H. W.; Chen, X. L.; Tang, Y. F.; Lu, M. H.; Chen, Y. F.

2009-11-01

Drug delivery through hollow microneedle (HMN) arrays has now been recognized as one of the most promising techniques because it minimizes the shortcomings of the traditional drug delivery methods and has many exciting advantages—pain free and tunable release rates, for example. However, this drug delivery method has been hindered greatly from mass clinical application because of the high fabrication cost of HMN arrays. Hence, we developed a simple and cost-effective procedure using silica needles as templates to massively fabricate HMN arrays by using popular materials and industrially applicable processes of micro- imprint, hot embossing, electroplating and polishing. Metal HMN arrays with high quality are prepared with great flexibility with tunable parameters of area, length of needle, size of hollow and array dimension. This efficient and cost-effective fabrication method can also be applied to other applications after minor alterations, such as preparation of optic, acoustic and solar harvesting materials and devices.

Near-Earth asteroids: Metals occurrence, extraction, and fabrication

Science.gov (United States)

Westfall, Richard

Near-earth asteroids occur in three principle types of orbits: Amor, Apollo, and Aten. Amor asteroids make relatively close (within 0.3 AU) approaches to the earth's orbit, but do not actually overlap it. Apollo asteroids spend most of their time outside the earth's orbital path, but at some point of close approach to the sun, they cross the orbit of the earth. Aten asteroids are those whose orbits remain inside the earth's path for the majority of their time, with semi-major axes less than 0.1 AU. Near-earth orbit asteroids include: stones, stony-irons, irons, carbonaceous, and super-carbonaceous. Metals within these asteroids include: iron, nickel, cobalt, the platinum group, aluminum, titanium, and others. Focus is on the extraction of ferrous and platinum group metals from the stony-iron asteroids, and the iron asteroids. Extraction of the metal fraction can be accomplished through the use of tunnel-boring-machines (TBM) in the case of the stony-irons. The metals within the story-iron asteroids occur as dispersed granules, which can be separated from the stony fraction through magnetic and gaseous digestion separation techniques. The metal asteroids are processes by drilling and gaseous digestion or by gaseous digestion alone. Manufacturing of structures, housings, framing networks, pressure vessels, mirrors, and other products is accomplished through the chemical vapor deposition (CVD) of metal coating on advanced composites and on the inside of contour-defining inflatables (CDI). Metal coatings on advanced composites provide: resistance to degradation in the hostile environments of space; superior optical properties; superior heat dissipation; service as wear coatings; and service as evidential coatings. Metal coatings on the inside of CDI produce metal load-bearing products. Fibers such as graphite, kevlar, glass, ceramic, metal, etc., can be incorporated in the metal coatings on the inside of CDI producing metal matrix products which exhibit high strength

Mould insert fabrication of a single-mode fibre connector alignment structure optimized by justified partial metallization

International Nuclear Information System (INIS)

Wissmann, Markus; Barié, Nicole; Guttmann, Markus; Schneider, Marc; Kolew, Alexander; Besser, Heino; Pfleging, Wilhelm; Hofmann, Andreas; Van Erps, Jürgen; Beri, Stefano; Watté, Jan

2015-01-01

For mass production of multiscale-optical components, microstructured moulding tools are needed. Metal tools are used for hot embossing or injection moulding of microcomponents made of a thermoplastic polymer. Microstructures with extremely tight specifications, e.g. low side wall roughness and high aspect ratios are generally made by lithographic procedures such as x-ray lithography or deep proton writing. However, these processes are unsuitable for low-cost mass production. An alternative manufacturing method of moulding tools has been developed at the Karlsruhe Institute of Technology (KIT). This article describes a mould insert fabrication and a new replication process for self-centring fibre alignment structures for low loss field installable single-mode fibre connectors, developed and fabricated by the Vrije Universiteit Brussel (VUB) in collaboration with TE Connectivity. These components are to be used in fibre-to-the-home networks and support the deployment and maintenance of fibre optic links. The special feature of this particular fibre connector is a self-centring fibre alignment, achieved by means of a through hole with deflectable cantilevers acting as micro-springs. The particular challenge is the electroforming of through holes with a centre hole diameter smaller than 125 µm. The fibre connector structure is prototyped by deep proton writing in polymethylmethacrylate and used as a sacrificial part. Using joining, physical vapour deposition and electroforming technology, a negative copy of the prototyped connector is transferred into nickel to be used as a moulding tool. The benefits of this replication technique are a rapid and economical fabrication of moulding tools with high-precision microstructures and a long tool life. With these moulding tools low-cost mass production is possible. We present the manufacturing chain we have established. Each individual manufacturing step of the mould insert fabrication will be shown in this report. The

Directed light fabrication of refractory metals and alloys

International Nuclear Information System (INIS)

Fonseca, J.C.; Lewis, G.K.; Dickerson, P.G.; Nemec, R.B.

1999-01-01

This report covers deposition of refractory pure metals and alloys using the Directed Light Fabrication (DLF) process and represents progress in depositing these materials through September 1998. In extending the DLF process technology to refractory metals for producing fully dense, structurally sound deposits, several problems have become evident. (1) Control of porosity in DLF-deposited refractory metal is difficult because of gases, apparently present in commercially purchased refractory metal powder starting materials. (2) The radiant heat from the molten pool during deposition melts the DLF powder feed nozzle. (3) The high reflectivity of molten refractory metals, at the Nd-YAG laser wavelength (1.06microm), produces damaging back reflections to the optical train and fiber optic delivery system that can terminate DLF processing. (4) The current limits on the maximum available laser power to prevent back reflection damage limit the parameter range available for densification of refractory metals. The work to date concentrated on niobium, W-25Re, and spherodized tungsten. Niobium samples, made from hydride-dehydride powder, had minimal gas porosity and the deposition parameters were optimized; however, test plates were not made at this time. W-25Re samples, containing sodium and potassium from a precipitation process, were made and porosity was a problem for all samples although minimized with some process parameters. Deposits made from potassium reduced tungsten that was plasma spherodized were made with minimized porosity. Results of this work indicate that further gas analysis of starting powders and de-gassing of starting powders and/or gas removal during deposition of refractory metals is required

The marginal fit of selective laser melting-fabricated metal crowns: an in vitro study.

Science.gov (United States)

Xu, Dan; Xiang, Nan; Wei, Bin

2014-12-01

The selective laser melting technique is attracting interest in prosthetic dentistry. The marginal fit is a key criterion for fixed restorations. The purpose of the study was to evaluate the marginal fit of cast cobalt-chromium alloy crowns versus the fit of selective laser melting-fabricated crowns. The marginal gap widths of 36 single crowns (18 selective laser melting-fabricated cobalt-chromium metal crowns and 18 cobalt-chromium cast crowns) were determined with a silicone replica technique. Each crown specimen was cut into 4 sections, and the marginal gap width of each cross section was evaluated by stereomicroscopy (× 100). The Student t test was used to evaluate whether significant differences occurred in the marginal gap widths between the selective laser melting-fabricated and cast cobalt-chromium metal crowns (α=.05). The mean marginal gap width of the cast crowns (170.19 μm) was significantly wider than that of the selective laser melting-fabricated crowns (102.86 μm). Selective laser melting-fabricate cobalt-chromium dental crowns found improved marginal gap widths compared with traditional cast crowns. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

The fabrication of short metallic nanotubes by templated electrodeposition

Energy Technology Data Exchange (ETDEWEB)

Chienwen, Huang; Hao Yaowu, E-mail: yhao@uta.ed [Department of Materials Science and Engineering, University of Texas at Arlington, Arlington, TX 76051 (United States)

2009-11-04

Template-based electrochemical synthesis has widely been used to produce metal nanowires and nanorods. Commercially available filtration membranes, such as anodic aluminum oxide (AAO) and polycarbonate track etch membranes, have commonly been utilized as hard templates for this purpose. In this process, a thick metal film is usually sputtered or vacuum evaporated onto one side of the membrane to block the pores and serve as the working electrode for the subsequent electrodeposition. Here, we show that during the deposition of the metal electrode for AAO membranes, the electrode metal diffuses into the pores and is deposited on the pore walls which leads to preferential electrodeposition of metal on the walls and therefore forms metal tubes. This phenomenon has been utilized to fabricate short nanotubes by carefully controlling the electrodeposition conditions. The process is a straightforward method for any electroplatable materials to form nanoscale tubular structures. The effects of working electrodes and electrodeposition conditions on the formation of tubular structures are discussed in detail. A new mechanism based on this simple fact is proposed to explain the formation of Ni tubes by Ni-Cu co-deposition. Also, we demonstrate how to distinguish magnetic nanotubes from nanorods by a simple magnetic measurement.

The fabrication of short metallic nanotubes by templated electrodeposition

International Nuclear Information System (INIS)

Huang Chienwen; Hao Yaowu

2009-01-01

Template-based electrochemical synthesis has widely been used to produce metal nanowires and nanorods. Commercially available filtration membranes, such as anodic aluminum oxide (AAO) and polycarbonate track etch membranes, have commonly been utilized as hard templates for this purpose. In this process, a thick metal film is usually sputtered or vacuum evaporated onto one side of the membrane to block the pores and serve as the working electrode for the subsequent electrodeposition. Here, we show that during the deposition of the metal electrode for AAO membranes, the electrode metal diffuses into the pores and is deposited on the pore walls which leads to preferential electrodeposition of metal on the walls and therefore forms metal tubes. This phenomenon has been utilized to fabricate short nanotubes by carefully controlling the electrodeposition conditions. The process is a straightforward method for any electroplatable materials to form nanoscale tubular structures. The effects of working electrodes and electrodeposition conditions on the formation of tubular structures are discussed in detail. A new mechanism based on this simple fact is proposed to explain the formation of Ni tubes by Ni-Cu co-deposition. Also, we demonstrate how to distinguish magnetic nanotubes from nanorods by a simple magnetic measurement.

Communication methods and production techniques in fixed prosthesis fabrication: a UK based survey. Part 2: Production techniques

Science.gov (United States)

Berry, J.; Nesbit, M.; Saberi, S.; Petridis, H.

2014-01-01

Aim The aim of this study was to identify the communication methods and production techniques used by dentists and dental technicians for the fabrication of fixed prostheses within the UK from the dental technicians' perspective. This second paper reports on the production techniques utilised. Materials and methods Seven hundred and eighty-two online questionnaires were distributed to the Dental Laboratories Association membership and included a broad range of topics, such as demographics, impression disinfection and suitability, and various production techniques. Settings were managed in order to ensure anonymity of respondents. Statistical analysis was undertaken to test the influence of various demographic variables such as the source of information, the location, and the size of the dental laboratory. Results The number of completed responses totalled 248 (32% response rate). Ninety percent of the respondents were based in England and the majority of dental laboratories were categorised as small sized (working with up to 25 dentists). Concerns were raised regarding inadequate disinfection protocols between dentists and dental laboratories and the poor quality of master impressions. Full arch plastic trays were the most popular impression tray used by dentists in the fabrication of crowns (61%) and bridgework (68%). The majority (89%) of jaw registration records were considered inaccurate. Forty-four percent of dental laboratories preferred using semi-adjustable articulators. Axial and occlusal under-preparation of abutment teeth was reported as an issue in about 25% of cases. Base metal alloy was the most (52%) commonly used alloy material. Metal-ceramic crowns were the most popular choice for anterior (69%) and posterior (70%) cases. The various factors considered did not have any statistically significant effect on the answers provided. The only notable exception was the fact that more methods of communicating the size and shape of crowns were utilised for

The Danish fabricated metal industry:

DEFF Research Database (Denmark)

Hansen, Teis

2010-01-01

This paper aims to contribute to the knowledge on innovation processes in low- and medium-low-tech industries. Today, industries characterised as high-tech are perceived to be central to economic development, as the research intensity shields them from competition from low-wage countries....... This is less the case for low-tech industries, but their economic importance continues to be large, however. It is thus interesting to analyse how they manage to remain competitive. The analysis focuses on a case study of the fabricated metal industry by identifying the innovation strategies followed by firms...... located in a part of Jutland, where this industry has experienced growth. It is found that the ability to create tailor-made solutions is central to the competitiveness of these medium-low-tech firms. Knowledge is thus highly important, yet in different ways than for high-tech industries. This illustrates...

Directed light fabrication of refractory metals and alloys

International Nuclear Information System (INIS)

Fonseca, J.C.; Lewis, G.K.; Dickerson, P.G.; Nemec, R.B.

1999-01-01

This report covers work performed under Order No. FA0000020 AN Contract DE-AC12-76SN00052 for deposition of refractory pure metals and alloys using the Directed Light Fabrication (DLF) process and represents the progress in depositing these materials through September 1998. In extending the DLF process technology to refractory metals for producing fully dense, structurally sound deposits, several problems have become evident. 1. Control of porosity in DLF-deposited refractory metal is difficult because of gases, apparently present in commercially purchased refractory metal powder starting materials. 2. The radiant heat from the molten pool during deposition melts the DLF powder feed nozzle. 3. The high reflectivity of molten refractory metals, at the Nd-YAG laser wavelength (1.06microm), produces damaging back reflections to the optical train and fiber optic delivery system that can terminate DLF processing. 4. The current limits on the maximum available laser power to prevent back reflection damage limit the parameter range available for densification of refractory metals. The work to date concentrated on niobium, W-25Re, and spherodized tungsten. Niobium samples, made from hydride-dehydride powder, had minimal gas porosity and the deposition parameters were optimized; however, test plates were not made at this time. W-25Re samples, containing sodium and potassium from a precipitation process, were made and porosity was a problem for all samples although minimized with some process parameters. Deposits made from potassium reduced tungsten that was plasma spherodized were made with minimized porosity. Results of this work indicate that further gas analysis of starting powders and de-gassing of starting powders and/or gas removal during deposition of refractory metals is required

Imprinting of metal receptors into multilayer polyelectrolyte films: fabrication and applications in marine antifouling

NARCIS (Netherlands)

Puniredd, S.R.; Janczewski, D.; Go, D.P.; Zhu, X.; Guo, S.; Teo, S.L-M.; Lee, S.S.C.; Vancso, Gyula J.

2015-01-01

Polymeric films constructed using the layer-by-layer (LbL) fabrication process were employed as a platform for metal ion immobilization and applied as a marine antifouling coating. The novel Cu2+ ion imprinting process described is based on the use of metal ion templates and LbL multilayer covalent

Optimization benefits analysis in production process of fabrication components

Science.gov (United States)

Prasetyani, R.; Rafsanjani, A. Y.; Rimantho, D.

2017-12-01

The determination of an optimal number of product combinations is important. The main problem at part and service department in PT. United Tractors Pandu Engineering (shortened to PT.UTPE) Is the optimization of the combination of fabrication component products (known as Liner Plate) which influence to the profit that will be obtained by the company. Liner Plate is a fabrication component that serves as a protector of core structure for heavy duty attachment, such as HD Vessel, HD Bucket, HD Shovel, and HD Blade. The graph of liner plate sales from January to December 2016 has fluctuated and there is no direct conclusion about the optimization of production of such fabrication components. The optimal product combination can be achieved by calculating and plotting the amount of production output and input appropriately. The method that used in this study is linear programming methods with primal, dual, and sensitivity analysis using QM software for Windows to obtain optimal fabrication components. In the optimal combination of components, PT. UTPE provide the profit increase of Rp. 105,285,000.00 for a total of Rp. 3,046,525,000.00 per month and the production of a total combination of 71 units per unit variance per month.

Metal-nanoparticle single-electron transistors fabricated using electromigration

DEFF Research Database (Denmark)

Bolotin, K I; Kuemmeth, Ferdinand; Pasupathy, A N

2004-01-01

We have fabricated single-electron transistors from individual metal nanoparticles using a geometry that provides improved coupling between the particle and the gate electrode. This is accomplished by incorporating a nanoparticle into a gap created between two electrodes using electromigration, all...... on top of an oxidized aluminum gate. We achieve sufficient gate coupling to access more than ten charge states of individual gold nanoparticles (5–15 nm in diameter). The devices are sufficiently stable to permit spectroscopic studies of the electron-in-a-box level spectra within the nanoparticle as its...

LCA of metal nanomaterial production

DEFF Research Database (Denmark)

Miseljic, Mirko; Diaz, Elsa Gabriela Alvarado; Olsen, Stig Irving

The use of engineered nanomaterials (ENMs) in commercial product has reached a new stage, where consumers in their daily life are frequently encountered with products containing this new material class. Metal and metal-oxide nanomaterials are among the most commonly used ENMs in products. Potential......(OH)2 applied as additives in polypropylene (PP), and the production of PP with conventional additives that provide similar properties as the ENMs. Different scenarios of nanoproducts consisting of metal ENMs and PP were compared with current use of additives in PP products through a detailed cradle...

Mechanical anomaly impact on metal-oxide-semiconductor capacitors on flexible silicon fabric

KAUST Repository

Ghoneim, Mohamed T.; Kutbee, Arwa T.; Ghodsi Nasseri, Seyed Faizelldin; Bersuker, G.; Hussain, Muhammad Mustafa

2014-01-01

We report the impact of mechanical anomaly on high-κ/metal-oxide-semiconductor capacitors built on flexible silicon (100) fabric. The mechanical tests include studying the effect of bending radius up to 5 mm minimum bending radius with respect

Fabrication of metallic nanoparticles by spinodal dewetting of thin films: A high-throughput approach

Energy Technology Data Exchange (ETDEWEB)

Michalak, William D.; Miller, James B. [U.S. Department of Energy, National Energy Technology Laboratory, Pittsburgh, PA 15262 (United States); Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213 (United States); Yolcu, Cem [Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213 (United States); Gellman, Andrew J., E-mail: gellman@cmu.edu [U.S. Department of Energy, National Energy Technology Laboratory, Pittsburgh, PA 15262 (United States); Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213 (United States)

2012-11-01

Metal nanoparticles on structured supports are used in a variety of technological applications including biosensing, energy harvesting, and electronics. In every case, the functions and properties of the metallic nanostructures depend on both their composition and structure (i.e. size, shape, and spatial distribution). Among the challenges to the development of metal nanoparticles for these applications is the characterization of relationships between their structure and their functional properties over multiple structural degrees of freedom spanning a large range of values. In this work, a method for creating a morphological gradient of metal nanoparticles on a substrate is described. The approach, suited for high-throughput fabrication and characterization, is based on spinodal dewetting of a metallic thin film from its substrate. Through control of initial film thickness, anneal temperature, and anneal time, spinodal dewetting results in supported nanoparticles with well-defined and controlled structure. The approach is demonstrated through its application to preparation of Pd nanoparticles on a silicon nitride substrate. The morphologies of the particles were characterized by scanning electron and atomic force microscopies. Free energy-based stability and topological analyses were used to confirm the dewetting mechanism. In addition, the stability theory provides a connection to the thermophysical properties of the resulting nanoparticle array. The dewetting approach is general to any metal/support system and provides an alternative, inexpensive, and robust means to rapidly create metal nanostructures with control of morphology. It shows promise for large scale production of metal nanoparticles structures, as well as understanding basic stability properties of thin metal films. - Highlights: Black-Right-Pointing-Pointer Pd dewetting from SiN occurs by a spinodal dewetting mechanism. Black-Right-Pointing-Pointer Dewetting occurs at temperatures well below the

Fabrication of metallic nanoparticles by spinodal dewetting of thin films: A high-throughput approach

International Nuclear Information System (INIS)

Michalak, William D.; Miller, James B.; Yolcu, Cem; Gellman, Andrew J.

2012-01-01

Metal nanoparticles on structured supports are used in a variety of technological applications including biosensing, energy harvesting, and electronics. In every case, the functions and properties of the metallic nanostructures depend on both their composition and structure (i.e. size, shape, and spatial distribution). Among the challenges to the development of metal nanoparticles for these applications is the characterization of relationships between their structure and their functional properties over multiple structural degrees of freedom spanning a large range of values. In this work, a method for creating a morphological gradient of metal nanoparticles on a substrate is described. The approach, suited for high-throughput fabrication and characterization, is based on spinodal dewetting of a metallic thin film from its substrate. Through control of initial film thickness, anneal temperature, and anneal time, spinodal dewetting results in supported nanoparticles with well-defined and controlled structure. The approach is demonstrated through its application to preparation of Pd nanoparticles on a silicon nitride substrate. The morphologies of the particles were characterized by scanning electron and atomic force microscopies. Free energy-based stability and topological analyses were used to confirm the dewetting mechanism. In addition, the stability theory provides a connection to the thermophysical properties of the resulting nanoparticle array. The dewetting approach is general to any metal/support system and provides an alternative, inexpensive, and robust means to rapidly create metal nanostructures with control of morphology. It shows promise for large scale production of metal nanoparticles structures, as well as understanding basic stability properties of thin metal films. - Highlights: ► Pd dewetting from SiN occurs by a spinodal dewetting mechanism. ► Dewetting occurs at temperatures well below the melting point of Pd. ► Spinodal dewetting allows

Fabrication and characterization of NiO based metal-insulator-metal diode using Langmuir-Blodgett method for high frequency rectification

Science.gov (United States)

Azad, Ibrahim; Ram, Manoj K.; Goswami, D. Yogi; Stefanakos, Elias

2018-04-01

Thin film metal-insulator-metal (MIM) diodes have attracted significant attention for use in infrared energy harvesting and detection applications. As demonstrated over the past decades, MIM or metal-insulator-insulator-metal (MIIM) diodes can operate at the THz frequencies range by quantum tunneling of electrons. The aim of this work is to synthesize required ultra-thin insulating layers and fabricate MIM diodes using the Langmuir-Blodgett (LB) technique. The nickel stearate (NiSt) LB precursor film was deposited on glass, silicon (Si), ITO glass and gold coated silicon substrates. The photodesorption (UV exposure) and the thermodesorption (annealing at 100 °C and 350 °C) methods were used to remove organic components from the NiSt LB film and to achieve a uniform homogenous nickel oxide (NiO) film. These ultrathin NiO films were characterized by EDS, AFM, FTIR and cyclic voltammetry methods, respectively. The MIM diode was fabricated by depositing nickel (Ni) on the NiO film, all on a gold (Au) plated silicon (Si) substrate. The current (I)-voltage (V) characteristics of the fabricated diode were studied to understand the conduction mechanism assumed to be tunneling of electron through the ultra-thin insulating layer. The sensitivity of the diode was measured to be as high as 35 V-1. The diode resistance was ˜100 ohms (at a bias voltage of 0.60 V), and the rectification ratio was about 22 (for a signal voltage of ±200 mV). At the bias point, the diode response demonstrated significant non-linearity and high asymmetry, which are very desirable characteristics for applications in infrared detection and harvesting.

The Use of Particulate Injection Moulding for Fabrication of Sports and Leisure Equipment from Titanium Metals

Directory of Open Access Journals (Sweden)

Paul D. Ewart

2018-02-01

Full Text Available Advanced materials such as metal alloys, carbon fibre composites and engineered polymers have improved athlete performances in all sporting applications. Advances in manufacturing has enabled increases in design complexity and the ability to rapidly prototype bespoke products using additive manufacturing also known as 3D printing. Another recent fabrication method widely used by medical, electronics and armaments manufacturers is particulate injection moulding. This process uses exact quantities of the required material, in powder form, minimising resource and energy requirements in comparison to conventional manufacturing techniques. The process utilises injection moulding techniques and tooling methods developed and used in the plastics industry. It can produce highly complex component geometries with excellent repeatability and reduced cost where volume manufacturing is required. This is especially important when considering materials such as titanium that are not only expensive in comparison to other metals but are difficult to process by regular machining and fabrication methods. This work presents a review of titanium use in the sporting sector with a focus on sporting devices and equipment. It also proposes that the sports engineering sector could increase performance and enable improvements in safety by switching to design methods appropriate to processing via the particulate injection moulding route.

The Production of Uranium Metal by Metal Hydrides Incorporated

Energy Technology Data Exchange (ETDEWEB)

Alexander, P. P.

1943-01-01

Metal Hydrides Incorporated was a pioneer in the production of uranium metal on a commercial scale and supplied it to all the laboratories interested in the original research, before other methods for its production were developed. Metal Hydrides Inc. supplied the major part of the metal for the construction of the first experimental pile which, on December 2, 1942, demonstrated the feasibility of the self-sustaining chain reaction and the release of atomic energy.

Fabrication and characterization of nanostructured metallic arrays with multi-shapes in monolayer and bilayer

Energy Technology Data Exchange (ETDEWEB)

Zhu Shaoli, E-mail: slzhu@ntu.edu.s [Nanyang Technological University, School of Electronic and Electrical Engineering (Singapore); Fu Yongqi [University of Electronic Science and Technology of China, School of Physical Electronics (China)

2010-06-15

Fabrication and characterization of nanostructured metallic arrays with different shapes in monolayer and bilayer were presented in this article. Nano-rhombic, nano-hexagon, and nano-column metallic arrays with the tunable shapes and in-plane dimensions were fabricated by means of vertical reactive ion etching and nanosphere lithography. The nanosize range of nanoparticles is from 50 to 300 nm. Optical characterization of these arrays was performed experimentally by spectroscopy. Specifically, we compared spectra width at site of full width at half maximum (FWHM) of the measured extinction spectra in the visible range to that of the traditional hexagonal-arranged triangular nanoparticles. The results show that the combination of vertical reactive ion etching and nanosphere lithography approach yields as tunable masks and provides an easy way for a flexible nanofabrication. These metallic arrays have narrower FWHM of the spectra which makes them potential applications in biosensors, data storage, and bioreactors.

Fabricating Zr-Based Bulk Metallic Glass Microcomponent by Suction Casting Using Silicon Micromold

Directory of Open Access Journals (Sweden)

Zhijing Zhu

2014-08-01

Full Text Available A suction casting process for fabricating Zr55Cu30Al10Ni5 bulk metallic glass microcomponent using silicon micromold has been studied. A complicated BMG microgear with 50 μm in module has been cast successfully. Observed by scanning electron microscopy and laser scanning confocal microscopy, we find that the cast microgear duplicates the silicon micromold including the microstructure on the surface. The amorphous state of the microgear is confirmed by transmission election microscopy. The nanoindentation hardness and elasticity modulus of the microgear reach 6.5 GPa and 94.5 GPa. The simulation and experimental results prove that the suction casting process with the silicon micromold is a promising one-step method to fabricate bulk metallic glass microcomponents with high performance for applications in microelectromechanical system.

What is the Potential for More Copper Fabrication in Zambia?

OpenAIRE

World Bank

2011-01-01

The copper fabrication industry lies between: (1) the industry that produces copper (as a commodity metal from mined ores as well as from recycling), and (2) the users of copper in finished products such as electronic goods. Copper fabrication involves the manufacture of products such as copper wire, wire rod, low-voltage cable, and other copper based semi-manufactures. Copper is clearly a...

Light metal production

Science.gov (United States)

Fan, Qinbai

2016-04-19

An electrochemical process for the production of light metals, particularly aluminum. Such a process involves contacting a light metal source material with an inorganic acid to form a solution containing the light metal ions in high concentration. The solution is fed to an electrochemical reactor assembly having an anode side containing an anode and a cathode side containing a cathode, with anode side and the cathode side separated by a bipolar membrane, with the solution being fed to the anode side. Light metal ions are electrochemically transferred through the bipolar membrane to the cathode side. The process further involves reducing the light metal ions to light metal powder. An associated processing system is also provided.

Concurrent material-fabrication optimization of metal-matrix laminates under thermo-mechanical loading

Science.gov (United States)

Saravanos, D. A.; Morel, M. R.; Chamis, C. C.

1991-01-01

A methodology is developed to tailor fabrication and material parameters of metal-matrix laminates for maximum loading capacity under thermomechanical loads. The stresses during the thermomechanical response are minimized subject to failure constrains and bounds on the laminate properties. The thermomechanical response of the laminate is simulated using nonlinear composite mechanics. Evaluations of the method on a graphite/copper symmetric cross-ply laminate were performed. The cross-ply laminate required different optimum fabrication procedures than a unidirectional composite. Also, the consideration of the thermomechanical cycle had a significant effect on the predicted optimal process.

Imprinting of metal receptors into multilayer polyelectrolyte films: fabrication and applications in marine antifouling

OpenAIRE

Puniredd, S.R.; Janczewski, D.; Go, D.P.; Zhu, X.; Guo, S.; Teo, S.L-M.; Lee, S.S.C.; Vancso, Gyula J.

2015-01-01

Polymeric films constructed using the layer-by-layer (LbL) fabrication process were employed as a platform for metal ion immobilization and applied as a marine antifouling coating. The novel Cu2+ ion imprinting process described is based on the use of metal ion templates and LbL multilayer covalent cross-linking. Custom synthesized, peptide mimicking polycations composed of histidine grafted poly(allylamine) (PAH) to bind metal ions, and methyl ester containing polyanions for convenient cross...

Fabrication and electrical characterization of partially metallized vias fabricated by inkjet

International Nuclear Information System (INIS)

Khorramdel, B; Mäntysalo, M

2016-01-01

Through silicon vias (TSVs), acting as vertical interconnections, play an important role in micro-electro-mechanical systems (MEMS) 3D wafer level packaging. Today, taking advantage of nanoparticle inks, inkjet technologies as local filling methods could be used to plate the inside the vias with a conductive material, rather than using a current method, such as chemical vapor deposition or electrolytic growth. This could decrease the processing time, cost and waste material produced. In this work, we have fabricated and demonstrated electrical characterization of TSVs with a top diameter of 85 μm, and partially metallized on their inside walls using silver nanoparticle ink and drop-on-demand inkjet printing. Electrical measurement showed that the resistance of a single via with a void free coverage from top to bottom could be less than 4 Ω, which is still acceptable for MEMS applications. (paper)

Fabrication and electrical characterization of partially metallized vias fabricated by inkjet

Science.gov (United States)

Khorramdel, B.; Mäntysalo, M.

2016-04-01

Through silicon vias (TSVs), acting as vertical interconnections, play an important role in micro-electro-mechanical systems (MEMS) 3D wafer level packaging. Today, taking advantage of nanoparticle inks, inkjet technologies as local filling methods could be used to plate the inside the vias with a conductive material, rather than using a current method, such as chemical vapor deposition or electrolytic growth. This could decrease the processing time, cost and waste material produced. In this work, we have fabricated and demonstrated electrical characterization of TSVs with a top diameter of 85 μm, and partially metallized on their inside walls using silver nanoparticle ink and drop-on-demand inkjet printing. Electrical measurement showed that the resistance of a single via with a void free coverage from top to bottom could be less than 4 Ω, which is still acceptable for MEMS applications.

A Passive Pressure Sensor Fabricated by Post-Fire Metallization on Zirconia Ceramic for High-Temperature Applications

Directory of Open Access Journals (Sweden)

Tao Luo

2014-09-01

Full Text Available A high-temperature pressure sensor realized by the post-fire metallization on zirconia ceramic is presented. The pressure signal can be read out wirelessly through the magnetic coupling between the reader antenna and the sensor due to that the sensor is equivalent to an inductive-capacitive (LC resonance circuit which has a pressure-sensitive resonance frequency. Considering the excellent mechanical properties in high-temperature environment, multilayered zirconia ceramic tapes were used to fabricate the pressure-sensitive structure. Owing to its low resistivity, sliver paste was chosen to form the electrical circuit via post-fire metallization, thereby enhancing the quality factor compared to sensors fabricated by cofiring with a high-melting-point metal such as platinum, tungsten or manganese. The design, fabrication, and experiments are demonstrated and discussed in detail. Experimental results showed that the sensor can operate at 600 °C with quite good coupling. Furthermore, the average sensitivity is as high as 790 kHz/bar within the measurement range between 0 and 1 Bar.

Fabrication of a 40-inch diameter ceramic to metal seal for PLT

International Nuclear Information System (INIS)

Lewin, G.; Mullaney, D.

1976-01-01

The design and fabrication details for the ceramic to metal seal for PLT are presented. The method used for the successful casting and firing of the 90% Al 2 O 3 ceramic body and the subsequent grinding and brazing of the ceramic to 430 S.S. are discussed

Fabrication and metallization of 3D electrospun nanofiberous architecture with gold and silver coating for applications related to electrochemical supercapacitors

Energy Technology Data Exchange (ETDEWEB)

Park, Keon Young [University of Pennsylvania, 3451 Walnut Street, Philadelphia, PA 19104 (United States); Ramaraj, B. [Research and Development Department, Central Institute of Plastics Engineering and Technology (CIPET), 630, Phase IV, GIDC, Vatva, Ahmedabad 382445 (India); Choi, Won Suk [Department of Chemistry, Hannam University, 461-6 Jeon min-dong, Yuseoung-gu, Daejeon 305-811 (Korea, Republic of); Yoon, Kuk Ro, E-mail: kryoon@hannam.ac.kr [Department of Chemistry, Hannam University, 461-6 Jeon min-dong, Yuseoung-gu, Daejeon 305-811 (Korea, Republic of)

2013-11-01

We have engineered a metallic architecture with high surface area and ultralow density for applications related to electrochemical supercapacitors. This is achieved first by design and fabrication of new annular collector template for electrospinning process, then the extrusion of polystyrene (PS) nanofiber through the fabricated annulus collector template followed by electroless plating of nanofiber assembly with gold and silver. The resultant three dimensional structures were characterized by optical microscopy (OM), Fourier-transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). The OM images suggest that the fabrication process causes the electrospun fibers to be hinged to one another, maximizing contact junctions enhancing mechanical stability. The coated structure has a superior surface area, is robust, and is freestanding – making it an attractive architectural design for an electrode. The SEM images show interlocking of nanofibers to one another, further indicating the potential application for this system as a high surface area, low density charge collector ideal for nanostructured growths. - Graphical abstract: A new annular collector template was designed and fabricated to create a 3D electrospun nanofiber assembly. This ultralight 3D architecture with high surface was electroless plated with silver and gold to assess its suitability for applications related to electrochemical supercapacitors. This structure is highly conductive leading us to believe that this product can be utilized as an alternate electrode charge collector. - Highlights: • A metallic architecture with high surface area and ultralow density was fabricated. • A new annular collector template for electrospinning was designed and fabricated. • Electrospun PS nanofibers with 3D structure were coated with silver and gold. • The coated structure is

Fabrication and metallization of 3D electrospun nanofiberous architecture with gold and silver coating for applications related to electrochemical supercapacitors

International Nuclear Information System (INIS)

Park, Keon Young; Ramaraj, B.; Choi, Won Suk; Yoon, Kuk Ro

2013-01-01

We have engineered a metallic architecture with high surface area and ultralow density for applications related to electrochemical supercapacitors. This is achieved first by design and fabrication of new annular collector template for electrospinning process, then the extrusion of polystyrene (PS) nanofiber through the fabricated annulus collector template followed by electroless plating of nanofiber assembly with gold and silver. The resultant three dimensional structures were characterized by optical microscopy (OM), Fourier-transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). The OM images suggest that the fabrication process causes the electrospun fibers to be hinged to one another, maximizing contact junctions enhancing mechanical stability. The coated structure has a superior surface area, is robust, and is freestanding – making it an attractive architectural design for an electrode. The SEM images show interlocking of nanofibers to one another, further indicating the potential application for this system as a high surface area, low density charge collector ideal for nanostructured growths. - Graphical abstract: A new annular collector template was designed and fabricated to create a 3D electrospun nanofiber assembly. This ultralight 3D architecture with high surface was electroless plated with silver and gold to assess its suitability for applications related to electrochemical supercapacitors. This structure is highly conductive leading us to believe that this product can be utilized as an alternate electrode charge collector. - Highlights: • A metallic architecture with high surface area and ultralow density was fabricated. • A new annular collector template for electrospinning was designed and fabricated. • Electrospun PS nanofibers with 3D structure were coated with silver and gold. • The coated structure is

Fabrication of functional superhydrophobic engineering materials via an extremely rapid and simple route.

Science.gov (United States)

Guo, Jie; Yu, Shen; Li, Jing; Guo, Zhiguang

2015-04-18

As important and irreplaceable engineering materials, metals are widely used in our daily life. Therefore, fabricating superhydrophobic surfaces on metal materials is of great significance, and applicable methods for industrial production are in urgent need. In this work, we provide a rapid and easy route for fabricating superhydrophobic films on metal materials through simple displacement deposition. This method includes two simple steps with each step being as short as one second. The obtained superhydrophobic surfaces are homogeneous and easy to repair. A miniature boat and a miniature box were used to test the buoyancy-increasing and oil absorption properties, respectively. This method is feasible for massive production of superhydrophobic metal materials applied to water transportation and oil spill clean-up areas.

Best practices in energy management: Experience with IAC assessments in the metals fabrication industry

International Nuclear Information System (INIS)

Clark, W.J.; Birkmire, L.K.

1999-01-01

The Industrial Technology and Energy Management (ITEM) division of the University City Science Center played a managerial role in founding and establishing the Energy Analysis and Diagnostic Center (EADC) program, now known as the Industrial Assessment Center (IAC) program. ITEM is responsible for the field management of 15 IACs in the western US. This DOE funded program utilizes teams of engineering faculty and students to conduct assessments of small to medium-size plants to identify cost savings by conserving energy, minimizing waste, and improving productivity. These assessments are provided at no direct cost to participating manufacturers, who are under no obligation to act on any recommendations. Centers managed by ITEM have conducted assessments in more than 700 plants in the metals fabrication industry (SIC 34). Recommendations made have the potential to reduce energy costs by about 10% on average. The average metals fabrication plant served achieved a 5.7% reduction in annual energy costs. These cost savings are accompanied by a reduction in energy usage of about 1.2 x 10 12 Btu/yr. Another benefit of the program is that it provides hands-on industrial experience and energy efficiency training for engineering students who will take these skills into industry. Since the program began more than 20 years ago, IACs have served less than 2% of the plants in this industry. To provide an effective means for plant managers to access and utilize the knowledge gained over the years ITEM has summarized recommendations that identify specific actions that plant management can take to save money

One-process fabrication of metal hierarchical nanostructures with rich nanogaps for highly-sensitive surface-enhanced Raman scattering

International Nuclear Information System (INIS)

Liu, Gui-qiang; Yu, Mei-dong; Liu, Zheng-qi; Liu, Xiao-shan; Huang, Shan; Pan, Ping-ping; Wang, Yan; Liu, Mu-lin; Gu, Gang

2015-01-01

One-process fabrication of highly active and reproducible surface-enhanced Raman scattering (SERS) substrates via ion beam deposition is reported. The fabricated metal–dielectric–metal (MDM) hierarchical nanostructure possesses rich nanogaps and a tunable resonant cavity. Raman scattering signals of analytes are dramatically strengthened due to the strong near-field coupling of localized surface plasmon resonances (LSPRs) and the strong interaction of LSPRs of metal NPs with surface plasmon polaritons (SPPs) on the underlying metal film by crossing over the dielectric spacer. The maximum Raman enhancement for the highest Raman peak at 1650 cm −1 is 13.5 times greater than that of a single metal nanoparticle (NP) array. Moreover, the SERS activity can be efficiently tailored by varying the size and number of voids between adjacent metal NPs and the thickness of the dielectric spacer. These findings may broaden the scope of SERS applications of MDM hierarchical nanostructures in biomedical and analytical chemistry. (paper)

Aerosol based direct-write micro-additive fabrication method for sub-mm 3D metal-dielectric structures

Science.gov (United States)

Rahman, Taibur; Renaud, Luke; Heo, Deuk; Renn, Michael; Panat, Rahul

2015-10-01

The fabrication of 3D metal-dielectric structures at sub-mm length scale is highly important in order to realize low-loss passives and GHz wavelength antennas with applications in wearable and Internet-of-Things (IoT) devices. The inherent 2D nature of lithographic processes severely limits the available manufacturing routes to fabricate 3D structures. Further, the lithographic processes are subtractive and require the use of environmentally harmful chemicals. In this letter, we demonstrate an additive manufacturing method to fabricate 3D metal-dielectric structures at sub-mm length scale. A UV curable dielectric is dispensed from an Aerosol Jet system at 10-100 µm length scale and instantaneously cured to build complex 3D shapes at a length scale  <1 mm. A metal nanoparticle ink is then dispensed over the 3D dielectric using a combination of jetting action and tilted dispense head, also using the Aerosol Jet technique and at a length scale 10-100 µm, followed by the nanoparticle sintering. Simulation studies are carried out to demonstrate the feasibility of using such structures as mm-wave antennas. The manufacturing method described in this letter opens up the possibility of fabricating an entirely new class of custom-shaped 3D structures at a sub-mm length scale with potential applications in 3D antennas and passives.

Aerosol based direct-write micro-additive fabrication method for sub-mm 3D metal-dielectric structures

International Nuclear Information System (INIS)

Rahman, Taibur; Panat, Rahul; Renaud, Luke; Heo, Deuk; Renn, Michael

2015-01-01

The fabrication of 3D metal-dielectric structures at sub-mm length scale is highly important in order to realize low-loss passives and GHz wavelength antennas with applications in wearable and Internet-of-Things (IoT) devices. The inherent 2D nature of lithographic processes severely limits the available manufacturing routes to fabricate 3D structures. Further, the lithographic processes are subtractive and require the use of environmentally harmful chemicals. In this letter, we demonstrate an additive manufacturing method to fabricate 3D metal-dielectric structures at sub-mm length scale. A UV curable dielectric is dispensed from an Aerosol Jet system at 10–100 µm length scale and instantaneously cured to build complex 3D shapes at a length scale  <1 mm. A metal nanoparticle ink is then dispensed over the 3D dielectric using a combination of jetting action and tilted dispense head, also using the Aerosol Jet technique and at a length scale 10–100 µm, followed by the nanoparticle sintering. Simulation studies are carried out to demonstrate the feasibility of using such structures as mm-wave antennas. The manufacturing method described in this letter opens up the possibility of fabricating an entirely new class of custom-shaped 3D structures at a sub-mm length scale with potential applications in 3D antennas and passives. (technical note)

Fabrication of WCp/NiBSi metal matrix composite by electron beam melting

Energy Technology Data Exchange (ETDEWEB)

Peng, Hui, E-mail: penghui@buaa.edu.cn [School of Materials Science and Engineering, Beihang University (BUAA), No. 37 Xueyuan Road, Beijing 100191 (China); Beijing Key Laboratory for Advanced Functional Material and Thin Film Technology, Beihang University, No. 37 Xueyuan Road, Beijing 100191 (China); Key Laboratory of Aerospace Materials & Performance (Ministry of Education), Beihang University, No. 37 Xueyuan Road, Beijing 100191 (China); Liu, Chang [School of Materials Science and Engineering, Beihang University (BUAA), No. 37 Xueyuan Road, Beijing 100191 (China); Guo, Hongbo, E-mail: guo.hongbo@buaa.edu.cn [School of Materials Science and Engineering, Beihang University (BUAA), No. 37 Xueyuan Road, Beijing 100191 (China); Beijing Key Laboratory for Advanced Functional Material and Thin Film Technology, Beihang University, No. 37 Xueyuan Road, Beijing 100191 (China); Key Laboratory of Aerospace Materials & Performance (Ministry of Education), Beihang University, No. 37 Xueyuan Road, Beijing 100191 (China); Yuan, Yuan [Zhuzhou Seed Cemented Carbide Technology Co. Ltd, No. 1099 Xiangda Road, Zhuzhou, Hunan 412000 (China); Gong, Shengkai; Xu, Huibin [School of Materials Science and Engineering, Beihang University (BUAA), No. 37 Xueyuan Road, Beijing 100191 (China); Beijing Key Laboratory for Advanced Functional Material and Thin Film Technology, Beihang University, No. 37 Xueyuan Road, Beijing 100191 (China); Key Laboratory of Aerospace Materials & Performance (Ministry of Education), Beihang University, No. 37 Xueyuan Road, Beijing 100191 (China)

2016-06-01

A blend of NiBSi and WC powders was used as raw material for fabricating a metal matrix composite (MMC) by electron beam melting (EBM). Dense and crack-free microstructure was produced with evenly distributed WC reinforcements. Mechanical properties, including macro- and micro-hardness, flexural strength, impact toughness and compressive strength, were investigated.

Fabrication of WCp/NiBSi metal matrix composite by electron beam melting

International Nuclear Information System (INIS)

Peng, Hui; Liu, Chang; Guo, Hongbo; Yuan, Yuan; Gong, Shengkai; Xu, Huibin

2016-01-01

A blend of NiBSi and WC powders was used as raw material for fabricating a metal matrix composite (MMC) by electron beam melting (EBM). Dense and crack-free microstructure was produced with evenly distributed WC reinforcements. Mechanical properties, including macro- and micro-hardness, flexural strength, impact toughness and compressive strength, were investigated.

Rapid selective metal patterning on polydimethylsiloxane (PDMS) fabricated by capillarity-assisted laser direct write

KAUST Repository

Lee, Ming-Tsang

2011-08-12

In this study we demonstrate a novel approach for the rapid fabricating micro scale metal (silver) patterning directly on a polydimethylsiloxane (PDMS) substrate. Silver nanoparticles were sintered on PDMS to form conductive metal films using laser direct write (LDW) technology. To achieve good metal film quality, a capillarity-assisted laser direct writing (CALDW) of nanoparticle suspensions on a low surface energy material (PDMS) was utilized. Experimental results showed controllable electrical conductivities and good film properties of the sintered silver patterns. This study reveals an advanced method of metal patterning on PDMS, and proposes a new research application of LDW in a nanoparticle colloidal environment. © 2011 IOP Publishing Ltd.

Fabrication of Metallic Quantum Dot Arrays For Nanoscale Nonlinear Optics

Science.gov (United States)

McMahon, M. D.; Hmelo, A. B.; Lopez Magruder, R., III; Weller Haglund, R. A., Jr.; Feldman, L. C.

2003-03-01

Ordered arrays of metal nanocrystals embedded in or sequestered on dielectric hosts have potential applications as elements of nonlinear or near-field optical circuits, as sensitizers for fluorescence emitters and photo detectors, and as anchor points for arrays of biological molecules. Metal nanocrystals are strongly confined electronic systems with size-, shape and spatial orientation-dependent optical responses. At the smallest scales (below about 15 nm diameter), their band structure is drastically altered by the small size of the system, and the reduced population of conduction-band electrons. Here we report on the fabrication of two-dimensional ordered metallic nanocrystal arrays, and one-dimensional nanocrystal-loaded waveguides for optical investigations. We have employed strategies for synthesizing metal nanocrystal composites that capitalize on the best features of focused ion beam (FIB) machining and pulsed laser deposition (PLD). The FIB generates arrays of specialized sites; PLD vapor deposition results in the directed self-assembly of Ag nanoparticles nucleated at the FIB generated sites on silicon substrates. We present results based on the SEM, AFM and optical characterization of prototype composites. This research has been supported by the U.S. Department of Energy under grant DE-FG02-01ER45916.

Characterization of complementary patterned metallic membranes produced simultaneously by a dual fabrication process

Science.gov (United States)

Hao, Qingzhen; Zeng, Yong; Wang, Xiande; Zhao, Yanhui; Wang, Bei; Chiang, I.-Kao; Werner, Douglas H.; Crespi, Vincent; Huang, Tony Jun

2010-11-01

An efficient technique is developed to fabricate optically thin metallic films with subwavelength patterns and their complements simultaneously. By comparing the spectra of the complementary films, we show that Babinet's principle nearly holds for these structures in the optical domain. Rigorous full-wave simulations are employed to verify the experimental observations. It is further demonstrated that a discrete-dipole approximation can qualitatively describe the spectral dependence of the metallic membranes on the geometry of the constituent particles as well as the illuminating polarization.

PZT Films Fabricated by Metal Organic Decomposition Method

Science.gov (United States)

Sobolev, Vladimir; Ishchuk, Valeriy

2014-03-01

High quality lead zirconate titanate films have been fabricated on different substrates by metal organic decomposition method and their ferroelectric properties have been investigated. Main attention was paid to studies of the influence of the buffer layer with conditional composition Pb1.3(Zr0.5Ti0.5) O3 on the properties of Pb(Zr0.5Ti0.5) O3 films fabricated on the polycrystalline titanium and platinum substrates. It is found that in the films on the Pt substrate (with or without the buffer layer) the dependencies of the remanent polarization and the coercivity field on the number of switching cycles do not manifest fatigue up to 109 cycles. The remanent polarization dependencies for films on the Ti substrate with the buffer layer containing an excess of PbO demonstrate an fundamentally new feature that consists of a remanent polarization increase after 108 switching cycles. The increase of remanent polarization is about 50% when the number of cycles approaches 1010, while the increase of the coercivity field is small. A monotonic increase of dielectric losses has been observed in all cases.

Design of conveyor utilization monitoring system: a case study of powder coating line in sheet metal fabrication

Science.gov (United States)

Prasetyo, Hoedi; Sugiarto, Yohanes; Nur Rosyidi, Cucuk

2018-03-01

Conveyor is a very useful equipment to replace manpower in transporting the goods. It highly influences the productivity, production capacity utilization and eventually the production cost. This paper proposes a system to monitor the utilization of conveyor at a low cost through a case study at powder coating process line in a sheet metal fabrication. Preliminary observation was conducted to identify the problems. The monitoring system was then built and executed. The system consists of two sub systems. First is sub system for collecting and transmitting the required data and the second is sub system for displaying the data. The system utilizes sensors, wireless data transfer and windows-based application. The test results showed that the whole system works properly. By this system, the productivity and status of the conveyor can be monitored in real time. This research enriches the development of conveyor monitoring system especially for implementation in small and medium enterprises.

Metal-ceramic alloys in dentistry: a review.

Science.gov (United States)

Roberts, Howard W; Berzins, David W; Moore, B Keith; Charlton, David G

2009-02-01

The purpose of this article is to review basic information about the alloys used for fabricating metal-ceramic restorations in dentistry. Their compositions, properties, advantages, and disadvantages are presented and compared. In addition to reviewing traditional noble-metal and base-metal metal-ceramic alloys, titanium and gold composite alloys are also discussed. A broad search of the published literature was performed using Medline to identify pertinent current articles on metal-ceramic alloys as well as articles providing a historical background about the development of these alloys. Textbooks, the internet, and manufacturers' literature were also used to supplement this information. The review discusses traditional as well as more recently-developed alloys and technologies used in dentistry for fabricating metal-ceramic restorations. Clear advantages and disadvantages for these alloy types are provided and discussed as well as the role that compositional variations have on the alloys' performance. This information should enable clinicians and technicians to easily identify the important physical properties of each type and their primary clinical indications. A number of alloys and metals are available for metal-ceramic use in dentistry. Each has its advantages and disadvantages, primarily based on its specific composition. Continuing research and development are resulting in the production of new technologies and products, giving clinicians even more choices in designing and fabricating metal-ceramic restorations.

Fabrication of full-color GaN-based light-emitting diodes on nearly lattice-matched flexible metal foils.

Science.gov (United States)

Kim, Hyeryun; Ohta, Jitsuo; Ueno, Kohei; Kobayashi, Atsushi; Morita, Mari; Tokumoto, Yuki; Fujioka, Hiroshi

2017-05-18

GaN-based light-emitting diodes (LEDs) have been widely accepted as highly efficient solid-state light sources capable of replacing conventional incandescent and fluorescent lamps. However, their applications are limited to small devices because their fabrication process is expensive as it involves epitaxial growth of GaN by metal-organic chemical vapor deposition (MOCVD) on single crystalline sapphire wafers. If a low-cost epitaxial growth process such as sputtering on a metal foil can be used, it will be possible to fabricate large-area and flexible GaN-based light-emitting displays. Here we report preparation of GaN films on nearly lattice-matched flexible Hf foils using pulsed sputtering deposition (PSD) and demonstrate feasibility of fabricating full-color GaN-based LEDs. It was found that introduction of low-temperature (LT) grown layers suppressed the interfacial reaction between GaN and Hf, allowing the growth of high-quality GaN films on Hf foils. We fabricated blue, green, and red LEDs on Hf foils and confirmed their normal operation. The present results indicate that GaN films on Hf foils have potential applications in fabrication of future large-area flexible GaN-based optoelectronics.

Bioactive Ti metal analogous to human cancellous bone: Fabrication by selective laser melting and chemical treatments.

Science.gov (United States)

Pattanayak, Deepak K; Fukuda, A; Matsushita, T; Takemoto, M; Fujibayashi, S; Sasaki, K; Nishida, N; Nakamura, T; Kokubo, T

2011-03-01

Selective laser melting (SLM) is a useful technique for preparing three-dimensional porous bodies with complicated internal structures directly from titanium (Ti) powders without any intermediate processing steps, with the products being expected to be useful as a bone substitute. In this study the necessary SLM processing conditions to obtain a dense product, such as the laser power, scanning speed, and hatching pattern, were investigated using a Ti powder of less than 45 μm particle size. The results show that a fully dense plate thinner than 1.8 mm was obtained when the laser power to scanning speed ratio was greater than 0.5 and the hatch spacing was less than the laser diameter, with a 30 μm thick powder layer. Porous Ti metals with structures analogous to human cancellous bone were fabricated and the compressive strength measured. The compressive strength was in the range 35-120 MPa when the porosity was in the range 75-55%. Porous Ti metals fabricated by SLM were heat-treated at 1300 °C for 1h in an argon gas atmosphere to smooth the surface. Such prepared specimens were subjected to NaOH, HCl, and heat treatment to provide bioactivity. Field emission scanning electron micrographs showed that fine networks of titanium oxide were formed over the whole surface of the porous body. These treated porous bodies formed bone-like apatite on their surfaces in a simulated body fluid within 3 days. In vivo studies showed that new bone penetrated into the pores and directly bonded to the walls within 12 weeks after implantation into the femur of Japanese white rabbits. The percentage bone affinity indices of the chemical- and heat-treated porous bodies were significantly higher than that of untreated implants. Copyright © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

International conference on design, fabrication and economy of metal structures

CERN Document Server

Farkas, József

2013-01-01

These are the proceedings of the International Conference on Design, Fabrication and Economy of Metal Structures held on 24-26 April 2013 in Miskolc, Hungary which contain 99 papers covering: Structural optimization Thin-walled structures Stability Fatigue Frames Fire Fabrication Welding technology Applications Steel-concrete composite Special problems The authors are from 23 different countries, ensuring that the themes covered are of worldwide interest and importance. The International Institute of Welding (IIW), the International Society of Structural and Multidisciplinary Optimization (ISSMO), the TÁMOP 4.2.1.B-10/2/KONV-2010-0001 project entitled “Increasing the quality of higher education through the development of research - development and innovation program at the University of Miskolc supported by the European Union, co-financed by the European Social Fund” and many other sponsors helped organizers to collect these valuable studies, the results of which will provoke discussion, and provide an i...

Scheme for the fabrication of ultrashort channel metal-oxide-semiconductor field-effect transistors

International Nuclear Information System (INIS)

Appenzeller, J.; Martel, R.; Solomon, P.; Chan, K.; Avouris, Ph.; Knoch, J.; Benedict, J.; Tanner, M.; Thomas, S.; Wang, K. L.

2000-01-01

We present a scheme for the fabrication of ultrashort channel length metal-oxide-semiconductor field-effect transistors (MOSFETs) involving nanolithography and molecular-beam epitaxy. The active channel is undoped and is defined by a combination of nanometer-scale patterning and anisotropic etching of an n ++ layer grown on a silicon on insulator wafer. The method is self-limiting and can produce MOSFET devices with channel lengths of less than 10 nm. Measurements on the first batch of n-MOSFET devices fabricated with this approach show very good output characteristics and good control of short-channel effects. (c) 2000 American Institute of Physics

Fabrication of sacrificial anode cathodic protection through casting method

International Nuclear Information System (INIS)

Mohd Sharif Sattar; Muhamad Daud; Siti Radiah Mohd Kamarudin; Azali Muhamad; Zaiton Selamat; Rusni Rejab

2007-01-01

Aluminum is one of the few metals that can be cast by all of the processes used in casting metals. These processes consist of die casting, permanent mold casting, sand casting (green sand and dry sand), plaster casting, investment casting, and continuous casting. Other processes such as lost foam, squeeze casting, and hot isostatic pressing are also used. Permanent mold casting method was selected in which used for fabricating of sacrificial anode cathodic protection. This product was ground for surface finished and fabricated in the cylindrical form and reinforced with carbon steel at a center of the anode. (Author)

Research on plant of metal fuel fabrication using casting process (2)

International Nuclear Information System (INIS)

Senda, Yasuhide; Yamada, Seiya

2005-02-01

In this research work for the metal fuel fabrication system (38 tHM/y), the studies of the concept of the main process equipments were performed based on the previous studies on the process design and the quality control system design. In this study the handling equipment of the products were also designed, according to these designs the handling periods were evaluated. Consequently the numbers of the equipments were assessed taking into account for the method of the blending the fuel composition. (1) Structural concept design of the major equipments, the fuel handling machine and the gravimetries in the main fabrication process. The structural concept were designed for the fuel composition blending equipment, the fuel pin assembling equipment, the sodium bonding equipment, the handling equipment for fuel slug palettes, the handling equipment for fuel pins and the gravimetries. (2) Re-assessment of the numbers of the equipments taking account of the handling periods. Based on the results of item (1) the periods were evaluated for the fuel slug and pin handling. Processing time of demolder is short, then the number of it is increased to two. Three vehicles are also added to transfer the slugs and a heel smoothly. (3) Design of the buffer storages. The buffer storages among the equipments were designed through the comparison of the process speed between the equipments taking into account for the handling periods. The required amount of the structural parts (for example cladding materials) was assessed for the buffer in the same manner and the amount of the buffer facilities were optimized. (author)

Recovery and use of fission product noble metals

International Nuclear Information System (INIS)

Jensen, G.A.; Rohmann, C.A.; Perrigo, L.D.

1980-06-01

Noble metals in fission products are of strategic value. Market prices for noble metals are rising more rapidly than recovery costs. A promising concept has been developed for recovery of noble metals from fission product waste. Although the assessment was made only for the three noble metal fission products (Rh, Pd, Ru), there are other fission products and actinides which have potential value

Process for fabrication of cermets

Science.gov (United States)

Landingham, Richard L [Livermore, CA

2011-02-01

Cermet comprising ceramic and metal components and a molten metal infiltration method and process for fabrication thereof. The light weight cermets having improved porosity, strength, durability, toughness, elasticity fabricated from presintered ceramic powder infiltrated with a molten metal or metal alloy. Alumina titanium cermets biocompatible with the human body suitable for bone and joint replacements.

Fabricating High-Quality 3D-Printed Alloys for Dental Applications

Directory of Open Access Journals (Sweden)

Min-Ho Hong

2017-07-01

Full Text Available Metal additive manufacturing (AM, especially selective laser melting (SLM, has been receiving particular attention because metallic functional structures with complicated configurations can be effectively fabricated using the technique. However, there still exist some future challenges for the fabrication of high-quality SLM products for dental applications. First, the surface quality of SLM products should be further improved by standardizing the laser process parameters or by appropriately post-treating the surface. Second, it should be guaranteed that dental SLM restorations have good dimensional accuracy and, in particular, a good marginal fit. Third, a definitive standard regarding building and scanning strategies, which affect the anisotropy, should be established to optimize the mechanical properties and fatigue resistance of SLM dental structures. Fourth, the SLM substructure’s bonding and support to veneering ceramic should be further studied to facilitate the use of esthetic dental restorations. Finally, the biocompatibility of SLM dental alloys should be carefully examined and improved to minimize the potential release of toxic metal ions from the alloys. Future research of SLM should focus on solving the above challenges, as well as on fabricating dental structures with “controlled” porosity.

Gel Fabrication of Molybdenum “Beads”

Energy Technology Data Exchange (ETDEWEB)

Lowden, Richard Andrew [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division; Armstrong, Beth L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division; Cooley, Kevin M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division

2016-11-01

Spherical molybdenum particles or “beads” of various diameters are of interest as feedstock materials for the additive manufacture of targets and assemblies used in the production of ⁹⁹Mo medical isotopes using accelerator technology. Small metallic beads or ball bearings are typically fabricated from wire; however, small molybdenum spheres cannot readily be produced in this manner. Sol-gel processes are often employed to produce small dense microspheres of metal oxides across a broad diameter range that in the case of molybdenum could be reduced and sintered to produce metallic spheres. These Sol-gel type processes were examined for forming molybdenum oxide beads; however, the molybdenum trioxide was chemically incompatible with commonly used gelation materials. As an alternative, an aqueous alginate process being assessed for the fabrication of oxide spheres for catalyst applications was employed to form molybdenum trioxide beads that were successfully reduced and sintered to produce small molybdenum spheres.

Fabrication of a Ti porous microneedle array by metal injection molding for transdermal drug delivery.

Science.gov (United States)

Li, Jiyu; Liu, Bin; Zhou, Yingying; Chen, Zhipeng; Jiang, Lelun; Yuan, Wei; Liang, Liang

2017-01-01

Microneedle arrays (MA) have been extensively investigated in recent decades for transdermal drug delivery due to their pain-free delivery, minimal skin trauma, and reduced risk of infection. However, porous MA received relatively less attention due to their complex fabrication process and ease of fracturing. Here, we present a titanium porous microneedle array (TPMA) fabricated by modified metal injection molding (MIM) technology. The sintering process is simple and suitable for mass production. TPMA was sintered at a sintering temperature of 1250°C for 2 h. The porosity of TPMA was approximately 30.1% and its average pore diameter was about 1.3 μm. The elements distributed on the surface of TPMA were only Ti and O, which may guarantee the biocompatibility of TPMA. TPMA could easily penetrate the skin of a human forearm without fracture. TPMA could diffuse dry Rhodamine B stored in micropores into rabbit skin. The cumulative permeated flux of calcein across TPMA with punctured skin was 27 times greater than that across intact skin. Thus, TPMA can continually and efficiently deliver a liquid drug through open micropores in skin.

Fabrication of a Ti porous microneedle array by metal injection molding for transdermal drug delivery.

Directory of Open Access Journals (Sweden)

Jiyu Li

Full Text Available Microneedle arrays (MA have been extensively investigated in recent decades for transdermal drug delivery due to their pain-free delivery, minimal skin trauma, and reduced risk of infection. However, porous MA received relatively less attention due to their complex fabrication process and ease of fracturing. Here, we present a titanium porous microneedle array (TPMA fabricated by modified metal injection molding (MIM technology. The sintering process is simple and suitable for mass production. TPMA was sintered at a sintering temperature of 1250°C for 2 h. The porosity of TPMA was approximately 30.1% and its average pore diameter was about 1.3 μm. The elements distributed on the surface of TPMA were only Ti and O, which may guarantee the biocompatibility of TPMA. TPMA could easily penetrate the skin of a human forearm without fracture. TPMA could diffuse dry Rhodamine B stored in micropores into rabbit skin. The cumulative permeated flux of calcein across TPMA with punctured skin was 27 times greater than that across intact skin. Thus, TPMA can continually and efficiently deliver a liquid drug through open micropores in skin.

Fabrication criteria applicable to Carem pods production

International Nuclear Information System (INIS)

Bianchi, D R; Azzinari, D; Gongora, P; Sabio Calvete, M; Ilarri, M; Perazzo, M; Duarte, J; Duarte, A; Rojas, J; Fleitas, G; Szieber, W C; Vizcaino, P

2012-01-01

In relation CAREM 25 project, PPFAE, CNEA, has been fabricated pods for fuel rods for that reactor. They were used the same fuel rods that to be irradiate and evaluate their behavior with that the same Uranium pellets. The scope of the agreement signed between the authorities of the CNEA and Institutt for Energiteknikk (IFE) in Norway, it contemplated irradiated fuel rods type CAREM fabricated from these fuel pods in the OECD Halden Reactor Project (HRP, venture led by IFE and integrate more than 16 countries). The work contemplates the production of two experimental item fuel pods. From the second item fuel pods will be used in the fuel rods. In this paper we analyze the sequences used; the results obtained and the general conditions for the development of the final process to be applied in the production phase for a reactor CAREM 25 (author)

Development of advanced spent fuel management process. The fabrication and oxidation behavior of simulated metallized spent fuel

Energy Technology Data Exchange (ETDEWEB)

Ro, Seung Gy; Shin, Y.J.; You, G.S.; Joo, J.S.; Min, D.K.; Chun, Y.B.; Lee, E.P.; Seo, H.S.; Ahn, S.B

1999-03-01

The simulated metallized spent fuel ingots were fabricated and evaluated the oxidation rates and the activation energies under several temperature conditions to develop an advanced spent fuel management process. It was also checked the alloying characteristics of the some elements with metal uranium. (Author). 3 refs., 1 tab., 36 figs.

Simple process to fabricate nitride alloy powders

International Nuclear Information System (INIS)

Yang, Jae Ho; Kim, Dong-Joo; Kim, Keon Sik; Rhee, Young Woo; Oh, Jang-Soo; Kim, Jong Hun; Koo, Yang Hyun

2013-01-01

Uranium mono-nitride (UN) is considered as a fuel material [1] for accident-tolerant fuel to compensate for the loss of fissile fuel material caused by adopting a thickened cladding such as SiC composites. Uranium nitride powders can be fabricated by a carbothermic reduction of the oxide powders, or the nitriding of metal uranium. Among them, a direct nitriding process of metal is more attractive because it has advantages in the mass production of high-purity powders and the reusing of expensive 15 N 2 gas. However, since metal uranium is usually fabricated in the form of bulk ingots, it has a drawback in the fabrication of fine powders. The Korea Atomic Energy Research Institute (KAERI) has a centrifugal atomisation technique to fabricate uranium and uranium alloy powders. In this study, a simple reaction method was tested to fabricate nitride fuel powders directly from uranium metal alloy powders. Spherical powder and flake of uranium metal alloys were fabricated using a centrifugal atomisation method. The nitride powders were obtained by thermal treating the metal particles under nitrogen containing gas. The phase and morphology evolutions of powders were investigated during the nitriding process. A phase analysis of nitride powders was also part of the present work. KAERI has developed the centrifugal rotating disk atomisation process to fabricate spherical uranium metal alloy powders which are used as advanced fuel materials for research reactors. The rotating disk atomisation system involves the tasks of melting, atomising, and collecting. A nozzle in the bottom of melting crucible introduces melt at the center of a spinning disk. The centrifugal force carries the melt to the edge of the disk and throws the melt off the edge. Size and shape of droplets can be controlled by changing the nozzle size, the disk diameter and disk speed independently or simultaneously. By adjusting the processing parameters of the centrifugal atomiser, a spherical and flake shape

Ultrastable Photoelectrodes for Solar Water Splitting Based on Organic Metal Halide Perovskite Fabricated by Lift-Off Process.

Science.gov (United States)

Nam, SeongSik; Mai, Cuc Thi Kim; Oh, Ilwhan

2018-05-02

Herein, we report an integrated photoelectrolysis of water employing organic metal halide (OMH) perovskite material. As generic OMH perovskite material and device architecture are highly susceptible to degradation by aqueous electrolytes, we have developed a versatile mold-cast and lift-off process to fabricate and assemble multipurpose metal encapsulation onto perovskite devices. With the metal encapsulation effectively protecting the perovskite cell and also functioning as electrocatalyst, the high-performance perovskite photoelectrodes exhibit high photovoltage and photocurrent that are effectively inherited from the original solid-state solar cell. More importantly, thus-fabricated perovskite photoelectrode demonstrates record-long unprecedented stability even at highly oxidizing potential in strong alkaline electrolyte. We expect that this versatile lift-off process can be adapted in a wide variety of photoelectrochemical devices to protect the material surfaces from corroding electrolyte and facilitate various electrochemical reactions.

Fabrication of nano-sized metal patterns on flexible polyethylene-terephthalate substrate using bi-layer nanoimprint lithography

Energy Technology Data Exchange (ETDEWEB)

Hwang, Seon Yong; Jung, Ho Yong [Department of Materials Science and Engineering, Korea University, Seoul, 136-701 (Korea, Republic of); Jeong, Jun-Ho [Nano-Mechanical Systems Research Center, Korea Institute of Machinery and Materials, Yuseong-gu Daejeon, 305-343 (Korea, Republic of); Lee, Heon, E-mail: heonlee@korea.ac.k [Department of Materials Science and Engineering, Korea University, Seoul, 136-701 (Korea, Republic of)

2009-05-29

Polymer films are widely used as a substrate for displays and for solar cells since they are cheap, transparent and flexible, and their material properties are easy to design. Polyethylene-terephthalate (PET) is especially useful for various applications requiring transparency, flexibility and good thermal and chemical resistance. In this study, nano-sized metal patterns were fabricated on flexible PET film by using nanoimprint lithography (NIL). Water-soluble poly-vinyl alcohol (PVA) resin was used as a planarization and sacrificial layer for the lift-off process, as it does not damage the PET films and can easily be etched off by using oxygen plasma. NIL was used to fabricate the nano-sized patterns on the non-planar or flexible substrate. Finally, a nano-sized metal pattern was successfully formed by depositing the metal layer over the imprinted resist patterns and applying the lift-off process, which is economic and environmentally friendly, to the PET films.

Simple and fast fabrication of superhydrophobic metal wire mesh for efficiently gravity-driven oil/water separation.

Science.gov (United States)

Song, Botao

2016-12-15

Superhydrophobic metal wire mesh (SMWM) has frequently been applied for the selective and efficient separation of oil/water mixture due to its porous structure and special wettability. However, current methods for the modification of metal wire mesh to be superhydrophobic suffered from problems with respect to complex experimental procedures or time-consuming process. In this study, a very simple, time-saving and single-step electrospray method was proposed to fabricate SMWM and the whole procedure required about only 2min. The morphology, surface composition and wettability of the SMWM were all evaluated, and the oil/water separation ability was further investigated. In addition, a commercial available sponge covered with SMWM was fabricated as an oil adsorbent for the purpose of oil recovery. This study demonstrated a convenient and fast method to modify the metal wire mesh to be superhydrophobic and such simple method might find practical applications in the large-scale removal of oils. Copyright © 2016 Elsevier Ltd. All rights reserved.

Facile 3D Metal Electrode Fabrication for Energy Applications via Inkjet Printing and Shape Memory Polymer

International Nuclear Information System (INIS)

Roberts, R C; Wu, J; Li, D C; Hau, N Y; Chang, Y H; Feng, S P

2014-01-01

This paper reports on a simple 3D metal electrode fabrication technique via inkjet printing onto a thermally contracting shape memory polymer (SMP) substrate. Inkjet printing allows for the direct patterning of structures from metal nanoparticle bearing liquid inks. After deposition, these inks require thermal curing steps to render a stable conductive film. By printing onto a SMP substrate, the metal nanoparticle ink can be cured and substrate shrunk simultaneously to create 3D metal microstructures, forming a large surface area topology well suited for energy applications. Polystyrene SMP shrinkage was characterized in a laboratory oven from 150-240°C, resulting in a size reduction of 1.97-2.58. Silver nanoparticle ink was patterned into electrodes, shrunk, and the topology characterized using scanning electron microscopy. Zinc-Silver Oxide microbatteries were fabricated to demonstrate the 3D electrodes compared to planar references. Characterization was performed using 10M potassium hydroxide electrolyte solution doped with zinc oxide (57g/L). After a 300s oxidation at 3Vdc, the 3D electrode battery demonstrated a 125% increased capacity over the reference cell. Reference cells degraded with longer oxidations, but the 3D electrodes were fully oxidized for 4 hours, and exhibited a capacity of 5.5mA-hr/cm 2 with stable metal performance

Mechanical anomaly impact on metal-oxide-semiconductor capacitors on flexible silicon fabric

KAUST Repository

Ghoneim, Mohamed T.

2014-06-09

We report the impact of mechanical anomaly on high-κ/metal-oxide-semiconductor capacitors built on flexible silicon (100) fabric. The mechanical tests include studying the effect of bending radius up to 5 mm minimum bending radius with respect to breakdown voltage and leakage current of the devices. We also report the effect of continuous mechanical stress on the breakdown voltage over extended periods of times.

Fabrication of Functionally Graded Ti and γ-TiAl by Laser Metal Deposition

Science.gov (United States)

Yan, Lei; Chen, Xueyang; Zhang, Yunlu; Newkirk, Joseph W.; Liou, Frank

2017-12-01

TiAl alloys have become a popular choice in the aerospace and automotive industries, owing to their high specific yield strength, specific modulus, and oxidation resistance over titanium alloys and Ni-based super alloys at elevated temperatures. Although laser metal deposition (LMD) techniques have been available for manufacturing metal alloys for a decade, limited research has been focused on joining intermetallic materials with dissimilar materials using LMD. Here, LMD was used to join titanium aluminide Ti-48Al-2Cr-2Nb and commercially pure titanium with an innovative transition path. The theorized transition was implemented by fabricating functionally graded material (FGM). Porosity- and crack-free deposits were successfully fabricated. Energy dispersive x-ray spectroscopy analysis revealed the final composition was very close to the design composition. X-ray diffraction showed the expected phases were formed. The Vickers hardness, ultimate tensile strength, and coefficient of thermal expansion were evaluated to characterize the FGM's mechanical and physical properties. The properties of the material were comparable to those of as-cast material as reported in the literature.

Fabrication and condensation characteristics of metallic superhydrophobic surface with hierarchical micro-nano structures

Science.gov (United States)

Chu, Fuqiang; Wu, Xiaomin

2016-05-01

Metallic superhydrophobic surfaces have various applications in aerospace, refrigeration and other engineering fields due to their excellent water repellent characteristics. This study considers a simple but widely applicable fabrication method using a two simultaneous chemical reactions method to prepare the acid-salt mixed solutions to process the metal surfaces with surface deposition and surface etching to construct hierarchical micro-nano structures on the surface and then modify the surface with low surface-energy materials. Al-based and Cu-based superhydrophobic surfaces were fabricated using this method. The Al-based superhydrophobic surface had a water contact angle of 164° with hierarchical micro-nano structures similar to the lotus leaves. The Cu-based surface had a water contact angle of 157° with moss-like hierarchical micro-nano structures. Droplet condensation experiments were also performed on these two superhydrophobic surfaces to investigate their condensation characteristics. The results show that the Al-based superhydrophobic surface has lower droplet density, higher droplet jumping probability, slower droplet growth rate and lower surface coverage due to the more structured hierarchical structures.

Fabrication of metallic surfaces with long-term superhydrophilic property using one-stop laser method

International Nuclear Information System (INIS)

Guan, Y.C.; Luo, F.F.; Lim, G.C.; Hong, M.H.; Zheng, H.Y.; Qi, Bojin

2015-01-01

Highlights: • One-stop laser method is presented to fabricate superhydrophilic surface on metals. • Wettability study shows the longest superhydrophilic duration as more than 1 month. • Water-soluble compounds, polar functional groups and dual-scale structures were formed. • Surface roughness shows an amplification effect of the wetting behavior. - Abstract: A simple method for fabricating stable superhydrophilic surface at metallic substrates is reported. This technique comprises irradiating the surface with multiple laser pulses. Surface wettability can be taylored through controlling laser parameters and processing conditions. The substrates were selected as aluminum alloy and stainless steel. Physical morphology and chemical composition of laser-textured surfaces were characterized by SEM, XPS, and 3D profiler measurements. Results showed that the longest wettability duration was achieved as more than 1 month for stainless steel and more than 200 h for Al alloy, respectively. The possible mechanism of hydrophilic behavior of laser-textured surfaces was discussed. The effect of surface topography on superhydrophilicity property was also evaluated. This study presents a promising method in fabricating long-term superhydrophilic surfaces, which is useful for improving adhesion or achieving water-assisted flow in industrial applications as well as developing cell-based technologies in biomedical applications

Application of siliceous metal product for preliminary deoxidizing of metal in open-hearth furnaces

International Nuclear Information System (INIS)

Luk'yanenko, A.A.; Evdokimov, A.V.; Kornilov, V.N.; Il'in, V.I.; Kuleshov, Yu.V.

1995-01-01

Metal wastes of abrasive processes-concomitant product of synthetic corundum production containing approximately 10 % Si - were tested for preliminary deoxidizing of metal in furnace to reduce manganese loss in burning and to increase the steel deoxidizing. The technology of preliminary deoxidizing of metal by siliceous metal product was mastered in the course of low carbon steel melting (st3sp, st4sp). The results of the study has shown that the use of siliceous metal product permits reducing the consumption of manganese-containing ferroalloys. 1 tab

Leading research on super metal. 3. Amorphous and nanostructured metallic materials; Super metal no sendo kenkyu. 3. Kogata buzai

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-03-01

Very fine structure control technique for amorphous and nanostructured metallic materials was reviewed to exceed the marginal performance of small metallic member materials. In Japan, high strength alloys and anticorrosion alloys are currently developed as an amorphous structure control technique, and ultra fine powder production and nano-compaction molding are studied for nanostructured materials. Fabrication of amorphous alloy wire materials and metal glass in USA are also introduced. Fabrication of metallic nanocrystals deposited within gas phase in Germany are attracting attention. The strength and abrasion resistance are remarkably enhanced by making nanostructured crystals and dispersing them. It may be most suitable to utilize amorphous and nanostructured metallic materials for earth-friendly materials having anticorrosion, and catalyst and biomaterial affinities, and also for magnetic materials. It is important for controlling micro-structures to clarify the formation mechanism of structures. For their processing techniques, the diversity and possibility are suggested, as to the condensation and solidification of gaseous and liquid phase metals, the molding and processing of very fine solid phase alloys, and the manufacturing members by heat treatment. 324 refs., 109 figs., 21 tabs.

THE BEHAVIOUR OF FABRICS USED FOR ANTIMIS PRODUCTION TO PILLING

Directory of Open Access Journals (Sweden)

CHIRILĂ Mihai Maxim

2016-05-01

Full Text Available The present study about the behaviour of plain textiles used for the production of antimis (Christian-orthodox liturgical item used in the liturgy to pilling explores the functional classification of different types of antimis as a textile product made out the following different types of fabrics: natural silk, flax, viscose, polyamide 6.6. Pilling is a phenomenon which consists of the formation of small balls made out of fibre congeries on the textile’s surface due to attrition and fatigue. For textiles used as liturgical items, the process of pilling formation includes the following stages: the emergence of the pilling surfaces (the formation of fuzzy, fibre tangle (appearance of small balls, and the detachment of small balls from the fabric’s surface. The analysis method of pilling for liturgical items made out the four types of fabrics mentioned above consists of stereoscopic microscopy techniques and electronic microscopy methods (SEM. The images of textiles samples (yarns and fabrics will be captured using a video microscope. Quantitative tests have been done to determine the metric number and the tex title of the above-mentioned fabrics. The increased resistance of silk to pilling compared to nylon, flax, and viscose can be attributed to the chemical properties of fibres and structural characteristics of silk fabric. The structural compactness of the same fiber mixture of natural silk fabric with bonded fabric will have a higher resistance coefficient to pilling compared to the other mentioned fabrics. Through this, the value of use and durability of the antimis will increase.

Fabrication of γ-Fe2O3 Nanoparticles by Solid-State Thermolysis of a Metal-Organic Framework, MIL-100(Fe, for Heavy Metal Ions Removal

Directory of Open Access Journals (Sweden)

Shengtao Hei

2014-01-01

Full Text Available Porous γ-Fe2O3 nanoparticles were prepared via a solid-state conversion process of a mesoporous iron(III carboxylate crystal, MIL-100(Fe. First, the MIL-100(Fe crystal that served as the template of the metal oxide was synthesized by a low-temperature (<100°C synthesis route. Subsequently, the porous γ-Fe2O3 nanoparticles were fabricated by facile thermolysis of the MIL-100(Fe powders via a two-step calcination treatment. The obtained γ-Fe2O3 was characterized by X-ray diffraction (XRD, N2 adsorption, X-ray photoelectron spectroscopy (XPS, and scanning electron microscopy (SEM techniques, and then used as an adsorbent for heavy metal ions removal in water treatment. This study illustrates that the metal-organic frameworks may be suitable precursors for the fabrication of metal oxides nanomaterials with large specific surface area, and the prepared porous γ-Fe2O3 exhibits a superior adsorption performance for As(V and As(III ions removal in water treatment.

National Machine Guarding Program: Part 1. Machine safeguarding practices in small metal fabrication businesses.

Science.gov (United States)

Parker, David L; Yamin, Samuel C; Brosseau, Lisa M; Xi, Min; Gordon, Robert; Most, Ivan G; Stanley, Rodney

2015-11-01

Metal fabrication workers experience high rates of traumatic occupational injuries. Machine operators in particular face high risks, often stemming from the absence or improper use of machine safeguarding or the failure to implement lockout procedures. The National Machine Guarding Program (NMGP) was a translational research initiative implemented in conjunction with two workers' compensation insures. Insurance safety consultants trained in machine guarding used standardized checklists to conduct a baseline inspection of machine-related hazards in 221 business. Safeguards at the point of operation were missing or inadequate on 33% of machines. Safeguards for other mechanical hazards were missing on 28% of machines. Older machines were both widely used and less likely than newer machines to be properly guarded. Lockout/tagout procedures were posted at only 9% of machine workstations. The NMGP demonstrates a need for improvement in many aspects of machine safety and lockout in small metal fabrication businesses. © 2015 The Authors. American Journal of Industrial Medicine published by Wiley Periodicals, Inc.

Fabrication of metal matrix composite by semi-solid powder processing

Energy Technology Data Exchange (ETDEWEB)

Wu, Yufeng [Iowa State Univ., Ames, IA (United States)

2011-01-01

Various metal matrix composites (MMCs) are widely used in the automotive, aerospace and electrical industries due to their capability and flexibility in improving the mechanical, thermal and electrical properties of a component. However, current manufacturing technologies may suffer from insufficient process stability and reliability and inadequate economic efficiency and may not be able to satisfy the increasing demands placed on MMCs. Semi-solid powder processing (SPP), a technology that combines traditional powder metallurgy and semi-solid forming methods, has potential to produce MMCs with low cost and high efficiency. In this work, the analytical study and experimental investigation of SPP on the fabrication of MMCs were explored. An analytical model was developed to understand the deformation mechanism of the powder compact in the semi-solid state. The densification behavior of the Al6061 and SiC powder mixtures was investigated with different liquid fractions and SiC volume fractions. The limits of SPP were analyzed in terms of reinforcement phase loading and its impact on the composite microstructure. To explore adoption of new materials, carbon nanotube (CNT) was investigated as a reinforcing material in aluminum matrix using SPP. The process was successfully modeled for the mono-phase powder (Al6061) compaction and the density and density distribution were predicted. The deformation mechanism at low and high liquid fractions was discussed. In addition, the compaction behavior of the ceramic-metal powder mixture was understood, and the SiC loading limit was identified by parametric study. For the fabrication of CNT reinforced Al6061 composite, the mechanical alloying of Al6061-CNT powders was first investigated. A mathematical model was developed to predict the CNT length change during the mechanical alloying process. The effects of mechanical alloying time and processing temperature during SPP were studied on the mechanical, microstructural and

Metal Production by Molten Salt Electrolysis

DEFF Research Database (Denmark)

Grjotheim, K.; Kvande, H.; Qingfeng, Li

Chemistry and electrochemistry of molten salts are reviewed. Technological aspects of electrolytic production of aluminium, magnesium, and other metals are comprehensively surveyed.......Chemistry and electrochemistry of molten salts are reviewed. Technological aspects of electrolytic production of aluminium, magnesium, and other metals are comprehensively surveyed....

Evaluation of metal-ceramic bond characteristics of three dental Co-Cr alloys prepared with different fabrication techniques.

Science.gov (United States)

Wang, Hongmei; Feng, Qing; Li, Ning; Xu, Sheng

2016-12-01

Limited information is available regarding the metal-ceramic bond strength of dental Co-Cr alloys fabricated by casting (CAST), computer numerical control (CNC) milling, and selective laser melting (SLM). The purpose of this in vitro study was to evaluate the metal-ceramic bond characteristics of 3 dental Co-Cr alloys fabricated by casting, computer numerical control milling, and selective laser melting techniques using the 3-point bend test (International Organization for Standardization [ISO] standard 9693). Forty-five specimens (25×3×0.5 mm) made of dental Co-Cr alloys were prepared by CAST, CNC milling, and SLM techniques. The morphology of the oxidation surface of metal specimens was evaluated by scanning electron microscopy (SEM). After porcelain application, the interfacial characterization was evaluated by SEM equipped with energy-dispersive spectrometry (EDS) analysis, and the metal-ceramic bond strength was assessed with the 3-point bend test. Failure type and elemental composition on the debonding interface were assessed by SEM/EDS. The bond strength was statistically analyzed by 1-way ANOVA and Tukey honest significant difference test (α=.05). The oxidation surfaces of the CAST, CNC, and SLM groups were different. They were porous in the CAST group but compact and irregular in the CNC and SLM groups. The metal-ceramic interfaces of the SLM and CNC groups showed excellent combination compared with those of the CAST group. The bond strength was 37.7 ±6.5 MPa for CAST, 43.3 ±9.2 MPa for CNC, and 46.8 ±5.1 MPa for the SLM group. Statistically significant differences were found among the 3 groups tested (P=.028). The debonding surfaces of all specimens exhibited cohesive failure mode. The oxidation surface morphologies and thicknesses of dental Co-Cr alloys are dependent on the different fabrication techniques used. The bond strength of all 3 groups exceed the minimum acceptable value of 25 MPa recommended by ISO 9693; hence, dental Co-Cr alloy

Fabrication and testing history prototypes and production units

Energy Technology Data Exchange (ETDEWEB)

1954-09-01

From April, 1951 to Aug, 1954, New York Shipbuilding Corp. carried out a subcontract with E.I. du Pont de Nemours & Company that was without parallel in the shipyard`s history. The work, designated the NYX Project for reasons of security, was vital to the operations of the Savannah River Plant, Aiken, S.C., which was then being designed and constructed by du Pont for the Atomic Energy Commission. It consisted of three broad parts: developmental and experimental work; fabrication and testing of a prototype unit; fabrication of production units. Five production units were ultimately built, one of them converted from the prototype. All were fabricated from stainless steel, and involved welding techniques, control of thermal distortion and tolerances never previously attempted on assemblies of comparable size. Du Pont`s technical experience and the background of New York Ship in heavy construction, particularly in the fabrication of naval gun turrets, were combined from the outset to resolve the difficult fabrication problems that occurred almost daily. Representatives of both companies worked together as a team in the shops and at supervisory levels to an unprecedented extent. The report is intended primarily to summarize New York Ship`s part in the project, but also includes some of du Pont`s activities since the work of the two organizations was so interrelated. Because of the scope of the program, it will not always be possible to provide detailed information, but rather to record what happened in general terms. Where the reader desires more specific data, he should refer to original plans and records, including various reports compiled during the course of the project.

Fabrication of conductive metallized nanostructures from self-assembled amphiphilic triblock copolymer templates: Nanospheres, nanowires, nanorings

International Nuclear Information System (INIS)

Zhu Jintao; Jiang Wei

2007-01-01

Various metallized nanostructures (such as rings, wires with controllable lengths, spheres) have been successfully fabricated by coating metallic nanolayers onto soft nanotemplates through simple electroless methods. In particular, bimetallic nanostructures have been obtained by using simple methods. The multiple functional polymeric nanostructures were obtained through the self-assembly of polystyrene/poly(4-vinyl pyridine) triblock copolymer (P4VP-b-PS-b-P4VP) in selective media by changing the common solvent properties. By combining field emission scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) characterization, it was confirmed that polymer/metal and bimetallic (Au at Ag) core-shell nanostructures could be achieved by chemical metal deposition method

Luminance enhancement in quantum dot light-emitting diodes fabricated with Field’s metal as the cathode

Science.gov (United States)

Basilio, Carlos; Oliva, Jorge; Lopez-Luke, Tzarara; Pu, Ying-Chih; Zhang, Jin Z.; Rodriguez, C. E.; de la Rosa, E.

2017-03-01

This work reports the fabrication and characterization of blue-green quantum dot light-emitting diodes (QD-LEDs) by using core/shell/shell Cd1-x Zn x Se/ZnSe/ZnS quantum dots. Poly [(9,9-bis(3‧-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] (PFN) was introduced in order to enhance the electron injection and also acted as a protecting layer during the deposition of the cathode (a Field’s metal sheet) on the organic/inorganic active layers at low temperature (63 °C). This procedure permitted us to eliminate the process of thermal evaporation for the deposition of metallic cathodes, which is typically used in the fabrication of OLEDs. The performance of devices made with an aluminum cathode was compared with that of devices which employed Field’s metal (FM) as the cathode. We found that the luminance and efficiency of devices with FM was ~70% higher with respect to those that employed aluminum as the cathode and their consumption of current was similar up to 13 V. We also demonstrated that the simultaneous presence of 1,2-ethanedethiol (EDT) and PFN enhanced the luminance in our devices and improved the current injection in QD-LEDs. Hence, the architecture for QD-LEDs presented in this work could be useful for the fabrication of low-cost luminescent devices.

Refining of crude uranium by solvent extraction for production of nuclear pure uranium metal

International Nuclear Information System (INIS)

Gupta, S.K.; Manna, S.; Singha, M.; Hareendran, K.N.; Chowdhury, S.; Satpati, S.K.; Kumar, K.

2007-01-01

Uranium is the primary fuel material for any nuclear fission energy program. Natural uranium contains only 0.712% of 235 U as fissile constituent. This low concentration of fissile isotope in natural uranium calls for a very high level of purity, especially with respect to neutron poisons like B, Cd, Gd etc. before it can be used as nuclear fuel. Solvent extraction is a widely used technique by which crude uranium is purified for reactor use. Uranium metal plant (UMP), BARC, Trombay is engaged in refining of uranium concentrate for production of nuclear pure uranium metal for fabrication of fuel for research reactors. This paper reviews some of the fundamental aspects of this refining process with some special references to UMP, BARC. (author)

Impact of process temperature on GaSb metal-oxide-semiconductor interface properties fabricated by ex-situ process

Energy Technology Data Exchange (ETDEWEB)

Yokoyama, Masafumi, E-mail: yokoyama@mosfet.t.u-tokyo.ac.jp; Takenaka, Mitsuru; Takagi, Shinichi [Department of Electrical Engineering and Information Systems, The University of Tokyo, Yayoi 2-11-16, Bunkyo, Tokyo 113-0032 (Japan); JST-CREST, Yayoi 2-11-16, Bunkyo, Tokyo 113-0032 (Japan); Asakura, Yuji [Department of Electrical Engineering and Information Systems, The University of Tokyo, Yayoi 2-11-16, Bunkyo, Tokyo 113-0032 (Japan); Yokoyama, Haruki [NTT Photonics Laboratories, NTT Corporation, Atsugi 243-0198 (Japan)

2014-06-30

We have studied the impact of process temperature on interface properties of GaSb metal-oxide-semiconductor (MOS) structures fabricated by an ex-situ atomic-layer-deposition (ALD) process. We have found that the ALD temperature strongly affects the Al{sub 2}O{sub 3}/GaSb MOS interface properties. The Al{sub 2}O{sub 3}/GaSb MOS interfaces fabricated at the low ALD temperature of 150 °C have the minimum interface-trap density (D{sub it}) of ∼4.5 × 10{sup 13 }cm{sup −2} eV{sup −1}. We have also found that the post-metalization annealing at temperature higher than 200 °C degrades the Al{sub 2}O{sub 3}/GaSb MOS interface properties. The low-temperature process is preferable in fabricating GaSb MOS interfaces in the ex-situ ALD process to avoid the high-temperature-induced degradations.

Ferrite control--Measurement problems and solutions during stainless steel fabrication

International Nuclear Information System (INIS)

Pickering, E.W.

1986-01-01

Ferrite is one of the magnetic phases found in many grades of otherwise nonmagnetic austenitic stainless steel weldments. Control of ferrite during the fabrication of cryogenic component parts is necessary to produce a reliable product, free of cracking and microfissuring. This is accomplished by balancing compositions in order to produce a small amount of ferrite which is generally accompanied with reduced toughness. Control of ferrite is essential during the fabrication of component parts. The means to accomplish this will vary with the type of material being welded, thickness, welding process, method of measurement and fabrication procedures. An application used during the fabrication of component parts for the Fast Flux Test Facility (FFTF) required specially formulated shielded manual arc welding (SMAW) electrodes and consumable inserts. Control of ferrite measurements and shop welding procedures were essential. The special materials and techniques were used to weld Type 316 stainless steel pipe joints, 28 in. (0.71 m) in diameter. By using three lots of electrodes, each with a different ferrite level, a compatible range of ferrite was achieved throughout the layers of weld metal. By extensive use of the Schaeffler and DeLong modified constitution diagrams for stainless steel weld metal, E-16-8-2 SMAW electrodes were developed with ''0'' ferrite level. The electrodes were used during fabrication of the Liquid Metal Fast Breader Reactor (LMFBR) component parts of Type 316 stainless steel. Metallographic evaluation of laboratory specimens, control of shop welding techniques and individual laboratory training of shop welders combined to produce a quality product

Production of metal particles and clusters

Science.gov (United States)

Mcmanus, S. P.

1982-01-01

The feasibility of producing novel metals or metal clusters in a low gravity environment was studied. The production of coordinately unsaturated metal carbonyls by thermolysis or photolysis of stable metal carbonyls has the potential to generate novel catalysts by this technique. Laser irradiation of available metal carbonyls was investigated. It is found that laser induced decomposition of metal carbonyls is feasible for producing a variety of coordinately unsaturated species. Formation of clustered species does occur but is hampered by weak metal-metal bonds.

Risk assessment of allergen metals in cosmetic products.

Science.gov (United States)

Sipahi, Hande; Charehsaz, Mohammad; Güngör, Zerrin; Erdem, Onur; Soykut, Buğra; Akay, Cemal; Aydin, Ahmet

2015-01-01

Cosmetics are one of the most common reasons for hospital referrals with allergic contact dermatitis. Because of the increased use of cosmetics within the population and an increase in allergy cases, monitoring of heavy metals, especially allergen metals, is crucial. The aim of this study was to investigate the concentration of allergen metals, nickel (Ni), cobalt (Co), and chromium (Cr), in the most commonly used cosmetic products including mascara, eyeliner, eye shadow, lipstick, and nail polish. In addition, for safety assessment of cosmetic products, margin of safety of the metals was evaluated. Forty-eight makeup products were purchased randomly from local markets and large cosmetic stores in Istanbul, Turkey, and an atomic absorption spectrometer was used for metal content determination. Risk assessment of the investigated cosmetic products was performed by calculating the systemic exposure dosage (SED) using Scientific Committee on Consumer Safety guideline. According to the results of this investigation in all the samples tested, at least two of the allergen metals, Ni and/or Co and/or Cr were detected. Moreover, 97% of the Ni-detected products, 96% of Cr- and 54% of Co-detected products, contained over 1 μg/g of this metals, which is the suggested ultimate target value for sensitive population and thereby can be considered as the possible allergen. On the basis of the results of this study, SED of the metals was negligible; however, contact dermatitis caused by cosmetics is most probably due to the allergen metal content of the products. In conclusion, to assess the safety of the finished products, postmarketing vigilance and routine monitoring of allergen metals are very important to protect public health.

POLYMER COMPOSITE FILMS WITH SIZE-SELECTED METAL NANOPARTICLES FABRICATED BY CLUSTER BEAM TECHNIQUE

DEFF Research Database (Denmark)

Ceynowa, F. A.; Chirumamilla, Manohar; Popok, Vladimir

2017-01-01

Formation of polymer films with size-selected silver and copper nanoparticles (NPs) is studied. Polymers are prepared by spin coating while NPs are fabricated and deposited utilizing a magnetron sputtering cluster apparatus. The particle embedding into the films is provided by thermal annealing...... after the deposition. The degree of immersion can be controlled by the annealing temperature and time. Together with control of cluster coverage the described approach represents an efficient method for the synthesis of thin polymer composite layers with either partially or fully embedded metal NPs....... Combining electron beam lithography, cluster beam deposition and thermal annealing allows to form ordered arrays of metal NPs on polymer films. Plasticity and flexibility of polymer host and specific properties added by coinage metal NPs open a way for different applications of such composite materials...

Method and device for fabricating dispersion fuel comprising fission product collection spaces

Science.gov (United States)

Shaber, Eric L; Fielding, Randall S

2015-05-05

A method of fabricating a nuclear fuel comprising a fissile material, one or more hollow microballoons, a phenolic resin, and metal matrix. The fissile material, phenolic resin and the one or more hollow microballoons are combined. The combined fissile material, phenolic resin and the hollow microballoons are heated sufficiently to form at least some fissile material carbides creating a nuclear fuel particle. The resulting nuclear fuel particle comprises one or more fission product collection spaces. In a preferred embodiment, the fissile material, phenolic resin and the one or more hollow microballoons are combined by forming the fissile material into microspheres. The fissile material microspheres are then overcoated with the phenolic resin and microballoon. In another preferred embodiment, the fissile material, phenolic resin and the one or more hollow microballoons are combined by overcoating the microballoon with the fissile material, and phenolic resin.

Explosive-emission cathode fabricated using track method

International Nuclear Information System (INIS)

Akap'ev, G.N.; Korenev, S.A.

1989-01-01

Fabrication technique for large area multipoint cathodes is described. The technique is based on channels filling with metal in the ion-irradiated dielectric film producted after channel etching. It is shown, that cathode may be used under explosive emission conditions. Characteristics of diode with the mentioned type cathodes are measured

Globally sustainable manganese metal production and use.

Science.gov (United States)

Hagelstein, Karen

2009-09-01

The "cradle to grave" concept of managing chemicals and wastes has been a descriptive analogy of proper environmental stewardship since the 1970s. The concept incorporates environmentally sustainable product choices-such as metal alloys utilized steel products which civilization is dependent upon. Manganese consumption is related to the increasing production of raw steel and upgrading ferroalloys. Nonferrous applications of manganese include production of dry-cell batteries, plant fertilizer components, animal feed and colorant for bricks. The manganese ore (high grade 35% manganese) production world wide is about 6 million ton/year and electrolytic manganese metal demand is about 0.7 million ton/year. The total manganese demand is consumed globally by industries including construction (23%), machinery (14%), and transportation (11%). Manganese is recycled within scrap of iron and steel, a small amount is recycled within aluminum used beverage cans. Recycling rate is 37% and efficiency is estimated as 53% [Roskill Metals and Minerals Reports, January 13, 2005. Manganese Report: rapid rise in output caused by Chinese crude steel production. Available from: http://www.roskill.com/reports/manganese.]. Environmentally sustainable management choices include identifying raw material chemistry, utilizing clean production processes, minimizing waste generation, recycling materials, controlling occupational exposures, and collecting representative environmental data. This paper will discuss two electrolytically produced manganese metals, the metal production differences, and environmental impacts cited to date. The two electrolytic manganese processes differ due to the addition of sulfur dioxide or selenium dioxide. Adverse environmental impacts due to use of selenium dioxide methodology include increased water consumption and order of magnitude greater solid waste generation per ton of metal processed. The use of high grade manganese ores in the electrolytic process also

Nanoparticles with tunable shape and composition fabricated by nanoimprint lithography.

Science.gov (United States)

Alayo, Nerea; Conde-Rubio, Ana; Bausells, Joan; Borrisé, Xavier; Labarta, Amilcar; Batlle, Xavier; Pérez-Murano, Francesc

2015-11-06

Cone-like and empty cup-shaped nanoparticles of noble metals have been demonstrated to provide extraordinary optical properties for use as optical nanoanntenas or nanoresonators. However, their large-scale production is difficult via standard nanofabrication methods. We present a fabrication approach to achieve arrays of nanoparticles with tunable shape and composition by a combination of nanoimprint lithography, hard-mask definition and various forms of metal deposition. In particular, we have obtained arrays of empty cup-shaped Au nanoparticles showing an optical response with distinguishable features associated with the excitations of localized surface plasmons. Finally, this route avoids the most common drawbacks found in the fabrication of nanoparticles by conventional top-down methods, such as aspect ratio limitation, blurring, and low throughput, and it can be used to fabricate nanoparticles with heterogeneous composition.

Nanoparticles with tunable shape and composition fabricated by nanoimprint lithography

International Nuclear Information System (INIS)

Alayo, Nerea; Bausells, Joan; Pérez-Murano, Francesc; Conde-Rubio, Ana; Labarta, Amilcar; Batlle, Xavier; Borrisé, Xavier

2015-01-01

Cone-like and empty cup-shaped nanoparticles of noble metals have been demonstrated to provide extraordinary optical properties for use as optical nanoanntenas or nanoresonators. However, their large-scale production is difficult via standard nanofabrication methods. We present a fabrication approach to achieve arrays of nanoparticles with tunable shape and composition by a combination of nanoimprint lithography, hard-mask definition and various forms of metal deposition. In particular, we have obtained arrays of empty cup-shaped Au nanoparticles showing an optical response with distinguishable features associated with the excitations of localized surface plasmons. Finally, this route avoids the most common drawbacks found in the fabrication of nanoparticles by conventional top-down methods, such as aspect ratio limitation, blurring, and low throughput, and it can be used to fabricate nanoparticles with heterogeneous composition. (paper)

Fabrication of dissimilar metal electrodes with nanometer interelectrode distance for molecular electronic device characterization

International Nuclear Information System (INIS)

Guillorn, Michael A.; Carr, Dustin W.; Tiberio, Richard C.; Greenbaum, Elias; Simpson, Michael L.

2000-01-01

We report a versatile process for the fabrication of dissimilar metal electrodes with a minimum interelectrode distance of less than 6 nm using electron beam lithography and liftoff pattern transfer. This technique provides a controllable and reproducible method for creating structures suited for the electrical characterization of asymmetric molecules for molecular electronics applications. Electrode structures employing pairs of Au electrodes and non-Au electrodes were fabricated in three different patterns. Parallel electrode structures 300 μm long with interelectrode distances as low as 10 nm, 75 nm wide electrode pairs with interelectrode distances less than 6 nm, and a multiterminal electrode structure with reproducible interelectrode distances of 8 nm were realized using this technique. The processing issues associated with the fabrication of these structures are discussed along with the intended application of these devices. (c) 2000 American Vacuum Society

Review on progressive microforming of bulk metal parts directly using sheet metals (Keynote Paper

Directory of Open Access Journals (Sweden)

Fu M.W.

2015-01-01

Full Text Available Due to the ubiquitous trend of product miniaturization, energy saving and weight reduction, micro/meso-scale parts have been widely used in many industrial clusters. Micromanufacturing processes for production of such micro/meso-scale parts are thus critically needed. Microforming, as one of these micro manufacturing processes, is a promising process and thus got many explorations and researches. Compared with the research on size effect affected deformation behaviours, less attention has been paid to the process development for mass production of micro-parts. The product quality and fabrication productivity of micro-parts depend on the involved process chain. To address the difficulty in handling and transporting of the micro-sized workpiece, development of a progressive microforming process for directly fabricating bulk micro-parts using sheet metals seems quite promising as it avoids or facilitates billet handling, transportation, positioning, and ejection in the process chain. In this paper, an intensive review on the latest development of progressive microforming technologies is presented. First of all, the paper summarizes the characteristic of progressive microforming directly using sheet metal. The size effect-affected deformation behaviour and the dimensional accuracy, deformation load, ductile fracture, and the surface finish of the microformed parts by progressive microforming using sheet metals are then presented. Finally, some research issues from the implementation of mass production perspective are also discussed.

A randomized, controlled intervention of machine guarding and related safety programs in small metal-fabrication businesses.

Science.gov (United States)

Parker, David L; Brosseau, Lisa M; Samant, Yogindra; Xi, Min; Pan, Wei; Haugan, David

2009-01-01

Metal fabrication employs an estimated 3.1 million workers in the United States. The absence of machine guarding and related programs such as lockout/tagout may result in serious injury or death. The purpose of this study was to improve machine-related safety in small metal-fabrication businesses. We used a randomized trial with two groups: management only and management-employee. We evaluated businesses for the adequacy of machine guarding (machine scorecard) and related safety programs (safety audit). We provided all businesses with a report outlining deficiencies and prioritizing their remediation. In addition, the management-employee group received four one-hour interactive training sessions from a peer educator. We evaluated 40 metal-fabrication businesses at baseline and 37 (93%) one year later. Of the three nonparticipants, two had gone out of business. More than 40% of devices required for adequate guarding were missing or inadequate, and 35% of required safety programs and practices were absent at baseline. Both measures improved significantly during the course of the intervention. No significant differences in changes occurred between the two intervention groups. Machine-guarding practices and programs improved by up to 13% and safety audit scores by up to 23%. Businesses that added safety committees or those that started with the lowest baseline measures showed the greatest improvements. Simple and easy-to-use assessment tools allowed businesses to significantly improve their safety practices, and safety committees facilitated this process.

National machine guarding program: Part 1. Machine safeguarding practices in small metal fabrication businesses

Science.gov (United States)

Yamin, Samuel C.; Brosseau, Lisa M.; Xi, Min; Gordon, Robert; Most, Ivan G.; Stanley, Rodney

2015-01-01

Background Metal fabrication workers experience high rates of traumatic occupational injuries. Machine operators in particular face high risks, often stemming from the absence or improper use of machine safeguarding or the failure to implement lockout procedures. Methods The National Machine Guarding Program (NMGP) was a translational research initiative implemented in conjunction with two workers' compensation insures. Insurance safety consultants trained in machine guarding used standardized checklists to conduct a baseline inspection of machine‐related hazards in 221 business. Results Safeguards at the point of operation were missing or inadequate on 33% of machines. Safeguards for other mechanical hazards were missing on 28% of machines. Older machines were both widely used and less likely than newer machines to be properly guarded. Lockout/tagout procedures were posted at only 9% of machine workstations. Conclusions The NMGP demonstrates a need for improvement in many aspects of machine safety and lockout in small metal fabrication businesses. Am. J. Ind. Med. 58:1174–1183, 2015. © 2015 The Authors. American Journal of Industrial Medicine published by Wiley Periodicals, Inc. PMID:26332060

Metal contact engineering and registration-free fabrication of complementary metal-oxide semiconductor integrated circuits using aligned carbon nanotubes.

Science.gov (United States)

Wang, Chuan; Ryu, Koungmin; Badmaev, Alexander; Zhang, Jialu; Zhou, Chongwu

2011-02-22

Complementary metal-oxide semiconductor (CMOS) operation is very desirable for logic circuit applications as it offers rail-to-rail swing, larger noise margin, and small static power consumption. However, it remains to be a challenging task for nanotube-based devices. Here in this paper, we report our progress on metal contact engineering for n-type nanotube transistors and CMOS integrated circuits using aligned carbon nanotubes. By using Pd as source/drain contacts for p-type transistors, small work function metal Gd as source/drain contacts for n-type transistors, and evaporated SiO(2) as a passivation layer, we have achieved n-type transistor, PN diode, and integrated CMOS inverter with an air-stable operation. Compared with other nanotube n-doping techniques, such as potassium doping, PEI doping, hydrazine doping, etc., using low work function metal contacts for n-type nanotube devices is not only air stable but also integrated circuit fabrication compatible. Moreover, our aligned nanotube platform for CMOS integrated circuits shows significant advantage over the previously reported individual nanotube platforms with respect to scalability and reproducibility and suggests a practical and realistic approach for nanotube-based CMOS integrated circuit applications.

PLC and SCADA based automation of injection casting process for casting of uranium-zirconium blanket fuel slugs for metallic fuel fabrication

International Nuclear Information System (INIS)

Yathish Kumar, G.; Jagadeeschandran, J.; Avvaru, Prafulla Kumar; Yadaw, Abhishek Kumar; Lavakumar, R.; Prabhu, T.V.; Muralidharan, P.; Anthonysamy, S.

2016-01-01

Fabrication of metallic (U-6wt.%Zr) slugs involves melting of binary alloy under vacuum and injection casting into quartz moulds at high pressure. Injection casting system housed inside glove box comprises of high vacuum, induction melting, high pressure control, motion control, mould preheating, chamber cooling, crucible handling and glove box pressure control systems. The technology development for process automation of injection casting system and process optimisation for fabrication of metallic (U-6%Zr) slugs is outlined in this paper. (author)

Physical masking process for integrating micro metallic structures on polymer substrate

DEFF Research Database (Denmark)

Islam, Mohammad Aminul; Hansen, Hans Nørgaard

2009-01-01

plasmon devices need micro metallic structures on a polymer substrate with an uniform metal layer thickness in the nanometer range. A well known fabrication process to achieve such metallic surface pattern on polymer substrate is photolithography which involves an expensive mask and toxic chemicals......Integration of micro metallic structures in polymer devices is a broad multi-disciplinary research field, consisting of various combinations of mechanical, chemical and physical fabrication methods. Each of the methods has its specific advantages and disadvantages. Some applications like surface....... The current study shows a novel approach for fabricating thin micro metallic structures on polymer substrates using a simple physical mask and a PVD equipment. The new process involves fewer process steps, it is cost effective and suitable for high volume industrial production. Current study suggests...

Fabrication of sub-wavelength photonic structures by nanoimprint lithography

Energy Technology Data Exchange (ETDEWEB)

Kontio, J.

2013-11-01

Nanoimprint lithography (NIL) is a novel but already a mature lithography technique. In this thesis it is applied to the fabrication of nanophotonic devices using its main advantage: the fast production of sub-micron features in high volume in a cost-effective way. In this thesis, fabrication methods for conical metal structures for plasmonic applications and sub-wavelength grating based broad-band mirrors are presented. Conical metal structures, nanocones, with plasmonic properties are interesting because they enable concentrating the energy of light in very tight spots resulting in very high local intensities of electromagnetic energy. The nanocone formation process is studied with several metals. Enhanced second harmonic generation using gold nanocones is presented. Bridged-nanocones are used to enhance Raman scattering from a dye solution. The sub-wavelength grating mirror is an interesting structure for photonics because it is very simple to fabricate and its reflectivity can be extended to the far infrared wavelength range. It also has polarization dependent properties which are used in this thesis to stabilize the output beam of infrared semiconductor disk laser. NIL is shown to be useful a technique in the fabrication of nanophotonic devices in the novel and rapidly growing field of plasmonics and also in more traditional, but still developing, semiconductor laser applications (orig.)

Fabrication of Three Dimensional Cu Metallic Photonic Crystal by Electroless Plating

International Nuclear Information System (INIS)

Wu, S-C; Hou, F-J; Jian, P-C Jang-; Tsai, M-S; Chen, M-C; Li, L-S; Huang, J-Y; Lin, S-Y

2007-01-01

A 3D copper (Cu) metallic photonic crystal (MPC) with 180nm line width was fabricated by electroless plating. The mold of 3D MPC for Cu replacement is poly-Si. It has been verified as an enhancing thermal photovoltaic effect while the mold was transferred into tungsten MPC by chemical vapor deposition method. The 5 layers structure of Cu MPC was clear observed with scanning electron microscopy. The photonic band-gap ranged from 1.5 to 13 μm was measured by Fourier transform infrared spectroscopy (FTIR) instrument

Large scale metal-free synthesis of graphene on sapphire and transfer-free device fabrication.

Science.gov (United States)

Song, Hyun Jae; Son, Minhyeok; Park, Chibeom; Lim, Hyunseob; Levendorf, Mark P; Tsen, Adam W; Park, Jiwoong; Choi, Hee Cheul

2012-05-21

Metal catalyst-free growth of large scale single layer graphene film on a sapphire substrate by a chemical vapor deposition (CVD) process at 950 °C is demonstrated. A top-gated graphene field effect transistor (FET) device is successfully fabricated without any transfer process. The detailed growth process is investigated by the atomic force microscopy (AFM) studies.

Microbial Metabolite Production for Accelerated Metal and Radionuclide Bioremediation (Microbial Metabolite Production Report)

International Nuclear Information System (INIS)

TURICK, CHARLES

2004-01-01

Biogeochemical activity is an ongoing and dynamic process due to bacterial activity in the subsurface. Bacteria contribute significantly to biotransformation of metals and radionuclides. As basic science reveals more information about specific mechanisms of bacterial-metal reduction, an even greater contribution of bacteria to biogeochemical activities is realized. An understanding and application of the mechanisms of metal and radionuclide reduction offers tremendous potential for development into bioremedial processes and technologies. Most bacteria are capable of biogeochemical transformation as a result of meeting nutrient requirements. These assimilatory mechanisms for metals transformation include production of small molecules that serve as electron shuttles for metal reduction. This contribution to biogeochemistry is small however due to only trace requirements for minerals by bacteria. Dissimilatory metal reducing bacteria (DMRB) reduce oxidized metals and insoluble mineral oxides as a means for biological energy production during growth. These types of bacteria offer considerable potential for bioremediation of environments contaminated with toxic metals and radionuclides because of the relatively large amount of metal biotransformation they require for growth. One of the mechanisms employed by some DMRB for electron transfer to insoluble metal oxides is melanin production. The electrochemical properties of melanin provide this polymeric, humic-type compound with electron shuttling properties. Melanin, specifically, pyomelanin, increases the rate and degree of metal reduction in DMRB as a function of pyomelanin concentration. Due to its electron shuttling behavior, only low femtogram quantities per cell are required to significantly increase metal reduction capacity of DMRB. Melanin production is not limited to DMRB. In fact melanin is one of the most common pigments produced by biological systems. Numerous soil microorganisms produce melanin, contributing

Fabrication of U-10wt.%Zr Fuel slug for SFR by Injection Casting

International Nuclear Information System (INIS)

Kim, Jong Hwan; Song, Hoon; Kim, Hyung Tae; Ko, Young Mo; Kim, Ki Hwan; Lee, Chan B.

2013-01-01

The fabrication technology of metal fuel has been developed by various methods such as rolling, swaging, wire drawing, and co-extrusion, but each of these methods had process limitations requiring an additional subsequent process, and needing the fabrication equipment is complex, which is not favorable for remote use. A practical process of metallic fuel fabrication for an SFR needs to be cost efficient, suitable for remote operation, and capable of mass production while reducing the amount of radioactive waste. Injection casting was chosen as the most promising technique, in the early 1950s, and this technique has been applied to fuel slug fabrication for the Experimental Breeder Reactor-II (EBR-II) driver and the Fast Flux Test Facility (FFTF) fuel pins. Because of the simplistic nature of the process and equipment, compared to other processes examined, this process has been successfully used in a remote operation environment for fueling of the EBR-II reactor. In this study, vacuum injection casting suitable for remote operation has been developed to fabricate metallic fuel for an SFR. Vacuum injection casting technique was developed to fabricate metallic fuel for an SFR. The appearance of the fabricated U-10wt.%Zr fuel was generally sound and the internal integrity was found to be satisfactory through gamma-ray radiography. Minimum fuel losses after casting relative to the initial charge amount of U-10wt.%Zr fuel slugs met the proposed goal of less than 0.1% fuel losses during fabrication. Modifications of the current facility system and advanced casting techniques are underway to produce higher quality fuel slugs

Fabrication of U-10wt.%Zr Fuel slug for SFR by Injection Casting

Energy Technology Data Exchange (ETDEWEB)

Kim, Jong Hwan; Song, Hoon; Kim, Hyung Tae; Ko, Young Mo; Kim, Ki Hwan; Lee, Chan B. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2013-10-15

The fabrication technology of metal fuel has been developed by various methods such as rolling, swaging, wire drawing, and co-extrusion, but each of these methods had process limitations requiring an additional subsequent process, and needing the fabrication equipment is complex, which is not favorable for remote use. A practical process of metallic fuel fabrication for an SFR needs to be cost efficient, suitable for remote operation, and capable of mass production while reducing the amount of radioactive waste. Injection casting was chosen as the most promising technique, in the early 1950s, and this technique has been applied to fuel slug fabrication for the Experimental Breeder Reactor-II (EBR-II) driver and the Fast Flux Test Facility (FFTF) fuel pins. Because of the simplistic nature of the process and equipment, compared to other processes examined, this process has been successfully used in a remote operation environment for fueling of the EBR-II reactor. In this study, vacuum injection casting suitable for remote operation has been developed to fabricate metallic fuel for an SFR. Vacuum injection casting technique was developed to fabricate metallic fuel for an SFR. The appearance of the fabricated U-10wt.%Zr fuel was generally sound and the internal integrity was found to be satisfactory through gamma-ray radiography. Minimum fuel losses after casting relative to the initial charge amount of U-10wt.%Zr fuel slugs met the proposed goal of less than 0.1% fuel losses during fabrication. Modifications of the current facility system and advanced casting techniques are underway to produce higher quality fuel slugs.

75 FR 70689 - Kaiser Aluminum Fabricated Products, LLC; Kaiser Aluminum-Greenwood Forge Division; Currently...

Science.gov (United States)

2010-11-18

... DEPARTMENT OF LABOR Employment and Training Administration [TA-W-70,376] Kaiser Aluminum Fabricated Products, LLC; Kaiser Aluminum- Greenwood Forge Division; Currently Known As Contech Forgings, LLC..., applicable to workers of Kaiser Aluminum Fabricated Products, LLC, Kaiser Aluminum-Greenwood Forge Division...

Production of magnesium metal

Science.gov (United States)

Blencoe, James G [Harriman, TN; Anovitz, Lawrence M [Knoxville, TN; Palmer, Donald A [Oliver Springs, TN; Beard, James S [Martinsville, VA

2010-02-23

A process of producing magnesium metal includes providing magnesium carbonate, and reacting the magnesium carbonate to produce a magnesium-containing compound and carbon dioxide. The magnesium-containing compound is reacted to produce magnesium metal. The carbon dioxide is used as a reactant in a second process. In another embodiment of the process, a magnesium silicate is reacted with a caustic material to produce magnesium hydroxide. The magnesium hydroxide is reacted with a source of carbon dioxide to produce magnesium carbonate. The magnesium carbonate is reacted to produce a magnesium-containing compound and carbon dioxide. The magnesium-containing compound is reacted to produce magnesium metal. The invention further relates to a process for production of magnesium metal or a magnesium compound where an external source of carbon dioxide is not used in any of the reactions of the process. The invention also relates to the magnesium metal produced by the processes described herein.

Synthesis of Uranium nitride powders using metal uranium powders

International Nuclear Information System (INIS)

Yang, Jae Ho; Kim, Dong Joo; Oh, Jang Soo; Rhee, Young Woo; Kim, Jong Hun; Kim, Keon Sik

2012-01-01

Uranium nitride (UN) is a potential fuel material for advanced nuclear reactors because of their high fuel density, high thermal conductivity, high melting temperature, and considerable breeding capability in LWRs. Uranium nitride powders can be fabricated by a carbothermic reduction of the oxide powders, or the nitriding of metal uranium. The carbothermic reduction has an advantage in the production of fine powders. However it has many drawbacks such as an inevitable engagement of impurities, process burden, and difficulties in reusing of expensive N 15 gas. Manufacturing concerns issued in the carbothermic reduction process can be solved by changing the starting materials from oxide powder to metals. However, in nitriding process of metal, it is difficult to obtain fine nitride powders because metal uranium is usually fabricated in the form of bulk ingots. In this study, a simple reaction method was tested to fabricate uranium nitride powders directly from uranium metal powders. We fabricated uranium metal spherical powder and flake using a centrifugal atomization method. The nitride powders were obtained by thermal treating those metal particles under nitrogen containing gas. We investigated the phase and morphology evolutions of powders during the nitriding process. A phase analysis of nitride powders was also a part of the present work

Fabrication of cermet fuel for fast reactor

International Nuclear Information System (INIS)

Mishra, Sudhir; Kumar, Arun; Kutty, T.R.G.; Kamath, H.S.

2011-01-01

Mixed oxide (MOX) (U,Pu)O 2 , and metallic (U,Pu ,Zr) fuels are considered promising fuels for the fast reactor. The fuel cycle of MOX is well established. The advantages of the oxide fuel are its easy fabricability, good performance in the reactor and a well established reprocessing technology. However the problems lie in low thermal conductivity , low density of the fuel leading to low breeding ratio and consequently longer doubling time. The metallic fuel has the advantages of high thermal conductivity, higher metal density and higher coefficient of linear expansion. The higher coefficient of linear expansion is good from the safety consideration (negative reactivity factor). Because of higher metal density it offers highest breeding ratio and shortest doubling time. Metallic fuel disadvantages comprise large swelling at high burnup, fuel cladding interaction and lower margin between operating and melting temperature. The optimal solution may lie in cermet fuel (U, PuO 2 ), where PuO 2 is dispersed in U metal matrix and combines the favorable features of both the fuel types. The advantages of this fuel include high thermal conductivity, larger margin between melting and operating temperature, ability to retain fission product etc. The matrix being of high density metal the advantage of high breeding ratio is also maintained. In this report some results of fabrication of cermet pellet comprising of UO 2 /PuO 2 dispersed in U metal powder through classical powder metallurgy route and characterization are presented. (author)

Noble metal-free RGO/TiO2 composite nanofiber with enhanced photocatalytic H2-production performance

Science.gov (United States)

Xu, Difa; Li, Lingling; He, Rongan; Qi, Lifang; Zhang, Liuyang; Cheng, Bei

2018-03-01

1D reduced graphene oxide (RGO)/TiO2 nanocomposite fibers were fabricated by a facile two-step method. These samples demonstrated high photocatalytic H2-production activity from methanol aqueous solution, even without the aid of noble metal. When the ratio of RGO is 0.25 wt%, the highest H2-production rate was achieved. It increased by 10 fold than bare TiO2, reaching 149 μmol h-1 g-1 with quantum efficiency (QE) of 0.75%. The reasons were as follows. Firstly, the RGO nanosheets acted as electron acceptors. Secondly, some shallow trap states at the surface or interface of TiO2 were created by the reduction of GO during calcination. Thirdly, the redox potential position of graphene/graphene- was suitable. Fourthly, RGO could efficiently promote the separation of photogenerated electron-hole pairs and significantly enhance the photocatalytic H2-production activity. This interpretation was corroborated by transient photocurrent response. The aforementioned marvelous results provided a probable solution to replace noble metals (such as Pt) by graphene as an effective cocatalyst.

Role of configuration management in improving quality of metal products

International Nuclear Information System (INIS)

Ali, U.; Kalsoom, T.

2007-01-01

The Configuration Management (CM) is an imperative discipline which helps in producing quality metal products for the customers. CM implements a graded approach to Configuration Items whose failure poses human as well as product losses. Effective CM provides information to Project Management, Quality Control, and Quality Assurance in identifying schedules and processes related to metal component production. The CM is a supportive function, mostly working side by side with Quality Assurance and Quality Control in the development / production of metal parts. The CM provides tools and guidelines for managing a product while Quality Assurance verifies and validates the same outside the scope of Configuration Audits. Configuration Management raises productivity of metal product, makes-available design reuse, reduces service and support costs, enhances visibility and eliminates rework on metal products. The elements of CM i.e. Identification, Control, Status Accounting and Audits playa vital role to enhance the quality of metal products. Only established CM System can make it possible to swing initial development criteria to final user friendly metal products. The challenges of today in our metal industry are to design and develop state-of-the-art products, for which, CM ideas given in this paper, will help to achieve all the set goals. (author)

Rare earth metal alloy magnets

International Nuclear Information System (INIS)

Harris, I.R.; Evans, J.M.; Nyholm, P.S.

1979-01-01

This invention relates to rare earth metal alloy magnets and to methods for their production. The technique is based on the fact that rare earth metal alloys (for e.g. cerium or yttrium) which have been crumbled to form a powder by hydride formation and decomposition can be used for the fabrication of magnets without the disadvantages inherent in alloy particle size reduction by mechanical milling. (UK)

Metal-Free 2D/2D Phosphorene/g-C3 N4 Van der Waals Heterojunction for Highly Enhanced Visible-Light Photocatalytic H2 Production.

Science.gov (United States)

Ran, Jingrun; Guo, Weiwei; Wang, Hailong; Zhu, Bicheng; Yu, Jiaguo; Qiao, Shi-Zhang

2018-04-30

The generation of green hydrogen (H 2 ) energy using sunlight is of great significance to solve the worldwide energy and environmental issues. Particularly, photocatalytic H 2 production is a highly promising strategy for solar-to-H 2 conversion. Recently, various heterostructured photocatalysts with high efficiency and good stability have been fabricated. Among them, 2D/2D van der Waals (VDW) heterojunctions have received tremendous attention, since this architecture can promote the interfacial charge separation and transfer and provide massive reactive centers. On the other hand, currently, most photocatalysts are composed of metal elements with high cost, limited reserves, and hazardous environmental impact. Hence, the development of metal-free photocatalysts is desirable. Here, a novel 2D/2D VDW heterostructure of metal-free phosphorene/graphitic carbon nitride (g-C 3 N 4 ) is fabricated. The phosphorene/g-C 3 N 4 nanocomposite shows an enhanced visible-light photocatalytic H 2 production activity of 571 µmol h -1 g -1 in 18 v% lactic acid aqueous solution. This improved performance arises from the intimate electronic coupling at the 2D/2D interface, corroborated by the advanced characterizations techniques, e.g., synchrotron-based X-ray absorption near-edge structure, and theoretical calculations. This work not only reports a new metal-free phosphorene/g-C 3 N 4 photocatalyst but also sheds lights on the design and fabrication of 2D/2D VDW heterojunction for applications in catalysis, electronics, and optoelectronics. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fabrication of electroslag welded Magnox fuel transport flasks

International Nuclear Information System (INIS)

Tuliani, S.S.

1979-01-01

The high weld metal deposition rate of the electroslag welding process offers an attractive method of fabricating nuclear fuel transport flasks from 370 mm (14.5in) thick steel plates. The paper describes pre-production trials carried out on full scale corner-section joints to establish that the weld metal meets the exacting mechanical property requirements for the Nuclear Industry. The paper presents results obtained on welds produced using two base metal compositions and two wires, one recommended for submerged-arc and the other for electroslag welding processes. Details of mechanical tests and metallographic examinations are given which led to the selection of the latter type of wire. It was found that while the weld metal deposited by this process may be sensitive to cracking, this can be avoided by careful selection of welding consumables and sound joints can be obtained under production conditions. (author)

Fit accuracy of metal partial removable dental prosthesis frameworks fabricated by traditional or light curing modeling material technique: An in vitro study

Science.gov (United States)

Anan, Mohammad Tarek M.; Al-Saadi, Mohannad H.

2015-01-01

Objective The aim of this study was to compare the fit accuracies of metal partial removable dental prosthesis (PRDP) frameworks fabricated by the traditional technique (TT) or the light-curing modeling material technique (LCMT). Materials and methods A metal model of a Kennedy class III modification 1 mandibular dental arch with two edentulous spaces of different spans, short and long, was used for the study. Thirty identical working casts were used to produce 15 PRDP frameworks each by TT and by LCMT. Every framework was transferred to a metal master cast to measure the gap between the metal base of the framework and the crest of the alveolar ridge of the cast. Gaps were measured at three points on each side by a USB digital intraoral camera at ×16.5 magnification. Images were transferred to a graphics editing program. A single examiner performed all measurements. The two-tailed t-test was performed at the 5% significance level. Results The mean gap value was significantly smaller in the LCMT group compared to the TT group. The mean value of the short edentulous span was significantly smaller than that of the long edentulous span in the LCMT group, whereas the opposite result was obtained in the TT group. Conclusion Within the limitations of this study, it can be concluded that the fit of the LCMT-fabricated frameworks was better than the fit of the TT-fabricated frameworks. The framework fit can differ according to the span of the edentate ridge and the fabrication technique for the metal framework. PMID:26236129

Methods for Fabricating Gradient Alloy Articles with Multi-Functional Properties

Science.gov (United States)

Hofmann, Douglas C. (Inventor); Borgonia, John Paul C. (Inventor); Dillon, Robert P. (Inventor); Suh, Eric J. (Inventor); Mulder, Jerry L. (Inventor); Gardner, Paul B. (Inventor)

2015-01-01

Systems and methods for fabricating multi-functional articles comprised of additively formed gradient materials are provided. The fabrication of multi-functional articles using the additive deposition of gradient alloys represents a paradigm shift from the traditional way that metal alloys and metal/metal alloy parts are fabricated. Since a gradient alloy that transitions from one metal to a different metal cannot be fabricated through any conventional metallurgy techniques, the technique presents many applications. Moreover, the embodiments described identify a broad range of properties and applications.

Description of Latvian Metal Production and Processing Enterprises' Air Emissions

OpenAIRE

Pubule, J; Zahare, D; Blumberga, D

2010-01-01

The metal production and processing sector in Latvia has acquired a stable position in the national economy. Smelting of ferrous and nonferrous metals, production of metalware, galvanisation, etc. are developed in Latvia. The metal production and processing sector has an impact on air quality due to polluting substances which are released in the air from metal treatment processes. Therefore it is necessary to determine the total volume of emissions produced by the metal production and process...

Marginal and internal fit of cobalt-chromium copings fabricated using the conventional and the direct metal laser sintering techniques: A comparative in vitro study.

Science.gov (United States)

Ullattuthodi, Sujana; Cherian, Kandathil Phillip; Anandkumar, R; Nambiar, M Sreedevi

2017-01-01

This in vitro study seeks to evaluate and compare the marginal and internal fit of cobalt-chromium copings fabricated using the conventional and direct metal laser sintering (DMLS) techniques. A master model of a prepared molar tooth was made using cobalt-chromium alloy. Silicone impression of the master model was made and thirty standardized working models were then produced; twenty working models for conventional lost-wax technique and ten working models for DMLS technique. A total of twenty metal copings were fabricated using two different production techniques: conventional lost-wax method and DMLS; ten samples in each group. The conventional and DMLS copings were cemented to the working models using glass ionomer cement. Marginal gap of the copings were measured at predetermined four points. The die with the cemented copings are standardized-sectioned with a heavy duty lathe. Then, each sectioned samples were analyzed for the internal gap between the die and the metal coping using a metallurgical microscope. Digital photographs were taken at ×50 magnification and analyzed using measurement software. Statistical analysis was done by unpaired t -test and analysis of variance (ANOVA). The results of this study reveal that no significant difference was present in the marginal gap of conventional and DMLS copings ( P > 0.05) by means of ANOVA. The mean values of internal gap of DMLS copings were significantly greater than that of conventional copings ( P < 0.05). Within the limitations of this in vitro study, it was concluded that the internal fit of conventional copings was superior to that of the DMLS copings. Marginal fit of the copings fabricated by two different techniques had no significant difference.

Transfer-Free Fabrication of Graphene Scaffolds on High-k Dielectrics from Metal-Organic Oligomers.

Science.gov (United States)

Pang, Qingqing; Wang, Deyan; Wang, Xiuyan; Feng, Shaoguang; Clark, Michael B; Li, Qiaowei

2016-09-28

In situ fabrication of graphene scaffold-ZrO2 nanofilms is achieved by thermal annealing of Zr-based metal-organic oligomers on SiO2 substrates. The structural similarities of the aromatic moieties in the ligand (phenyl-, naphthyl-, anthryl-, and pyrenyl-) compared to graphene play a major role in the ordering of the graphene scaffolds obtained. The depth profiling analysis reveals ultrathin carbon-pure or carbon-rich surfaces of the graphene scaffold-ZrO2 nanofilms. The graphene scaffolds with ∼96.0% transmittance in the visible region and 4.8 nm in thickness can be grown with this non-chemical vapor deposition method. Furthermore, the heterogeneous graphene scaffold-ZrO2 nanofilms show a low sheet resistance of 17.0 kΩ per square, corresponding to electrical conductivity of 3197 S m(-1). The strategy provides a facile method to fabricate graphene scaffolds directly on high-k dielectrics without transferring process, paving the way for its application in fabricating electronic devices.

Production of metal waste forms from spent fuel treatment

International Nuclear Information System (INIS)

Westphal, B.R.; Keiser, D.D.; Rigg, R.H.; Laug, D.V.

1995-01-01

Treatment of spent nuclear fuel at Argonne National Laboratory consists of a pyroprocessing scheme in which the development of suitable waste forms is being advanced. Of the two waste forms being proposed, metal and mineral, the production of the metal waste form utilizes induction melting to stabilize the waste product. Alloying of metallic nuclear materials by induction melting has long been an Argonne strength and thus, the transition to metallic waste processing seems compatible. A test program is being initiated to coalesce the production of the metal waste forms with current induction melting capabilities

Triangular metal wedges for subwavelength plasmon-polariton guiding at telecom wavelengths

DEFF Research Database (Denmark)

Boltasseva, Alexandra; Volkov, V.S.; Nielsen, Rasmus Bundgaard

2008-01-01

We report on subwavelength plasmon-polariton guiding by triangular metal wedges at telecom wavelengths. A high-quality fabrication procedure for making gold wedge waveguides, which is also mass- production compatible offering large-scale parallel fabrication of plasmonic components, is developed...

Fabrication of Gold-coated 3-D Woodpile Structures for Mid-IR Thermal Emitters

Science.gov (United States)

Li, Shengkai; Moridani, Amir; Kothari, Rohit; Lee, Jae-Hwang; Watkins, James

3-D metallic woodpile nanostructures possess enhancements in thermal radiation that are both wavelength and polarization specific and are promising for thermal-optical devices for various applications including thermal photovoltaics, self-cooling devices, and chemical and bio-sensors. However, current fabrication techniques for such structures are limited by slow speed, small area capability, the need for expensive facilities and, in general, are not suitable for high-throughput mass production. Here we demonstrate a new strategy for the fabrication of 3D metallic woodpile structures. Well-defined TiO2 woodpile structures were fabricated using a layer-by-layer nanoimprint method using TiO2 nanoparticle ink dispersions. The TiO2 woodpile was then coated with a high purity, conformal gold film via reactive deposition in supercritical carbon dioxide. The final gold-coated woodpile structures exhibit strong spectral and polarization specific thermal emission enhancements. The fabrication method demonstrated here is promising for high-throughput, low-cost preparation of 3D metallic woodpile structures and other 3D nanostructures. Center for Hierarchical Manufacturing, NSF.

Titanium Metal Powder Production by the Plasma Quench Process

Energy Technology Data Exchange (ETDEWEB)

R. A. Cordes; A. Donaldson

2000-09-01

The goals of this project included the scale-up of the titanium hydride production process to a production rate of 50 kg/hr at a purity level of 99+%. This goal was to be achieved by incrementally increasing the production capability of a series of reactor systems. This methodic approach was designed to allow Idaho Titanium Technologies to systematically address the engineering issues associated with plasma system performance, and powder collection system design and performance. With quality powder available, actual fabrication with the titanium hydride was to be pursued. Finally, with a successful titanium production system in place, the production of titanium aluminide was to be pursued by the simultaneously injection of titanium and aluminum precursors into the reactor system. Some significant accomplishments of the project are: A unique and revolutionary torch/reactor capable of withstanding temperatures up to 5000 C with high thermal efficiency has been operated. The dissociation of titanium tetrachloride into titanium powder and HC1 has been demonstrated, and a one-megawatt reactor potentially capable of producing 100 pounds per hour has been built, but not yet operated at the powder level. The removal of residual subchlorides and adsorbed HC1 and the sintering of powder to form solid bodies have been demonstrated. The production system has been operated at production rates up to 40 pounds per hour. Subsequent to the end of the project, Idaho Titanium Technologies demonstrated that titanium hydride powder can indeed be sintered into solid titanium metal at 1500 C without sintering aids.

National machine guarding program: Part 1. Machine safeguarding practices in small metal fabrication businesses

OpenAIRE

Parker, David L.; Yamin, Samuel C.; Brosseau, Lisa M.; Xi, Min; Gordon, Robert; Most, Ivan G.; Stanley, Rodney

2015-01-01

Background Metal fabrication workers experience high rates of traumatic occupational injuries. Machine operators in particular face high risks, often stemming from the absence or improper use of machine safeguarding or the failure to implement lockout procedures. Methods The National Machine Guarding Program (NMGP) was a translational research initiative implemented in conjunction with two workers' compensation insures. Insurance safety consultants trained in machine guarding used standardize...

Direct CVD Graphene Growth on Semiconductors and Dielectrics for Transfer-Free Device Fabrication.

Science.gov (United States)

Wang, Huaping; Yu, Gui

2016-07-01

Graphene is the most broadly discussed and studied two-dimensional material because of its preeminent physical, mechanical, optical, and thermal properties. Until now, metal-catalyzed chemical vapor deposition (CVD) has been widely employed for the scalable production of high-quality graphene. However, in order to incorporate the graphene into electronic devices, a transfer process from metal substrates to targeted substrates is inevitable. This process usually results in contamination, wrinkling, and breakage of graphene samples - undesirable in graphene-based technology and not compatible with industrial production. Therefore, direct graphene growth on desired semiconductor and dielectric substrates is considered as an effective alternative. Over the past years, there have been intensive investigations to realize direct graphene growth using CVD methods without the catalytic role of metals. Owing to the low catalytic activity of non-metal substrates for carbon precursor decomposition and graphene growth, several strategies have been designed to facilitate and engineer graphene fabrication on semiconductors and insulators. Here, those developed strategies for direct CVD graphene growth on semiconductors and dielectrics for transfer-free fabrication of electronic devices are reviewed. By employing these methods, various graphene-related structures can be directly prepared on desired substrates and exhibit excellent performance, providing versatile routes for varied graphene-based materials fabrication. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Universal liquid-phase laser fabrication of various nano-metals encapsulated by ultrathin carbon shells for deep-UV plasmonics.

Science.gov (United States)

Yu, Miao; Yang, Chao; Li, Xiao-Ming; Lei, Tian-Yu; Sun, Hao-Xuan; Dai, Li-Ping; Gu, Yu; Ning, Xue; Zhou, Ting; Wang, Chao; Zeng, Hai-Bo; Xiong, Jie

2017-06-29

The exploration of localized surface plasmon resonance (LSPR) beyond the usual visible waveband, for example within the ultraviolet (UV) or deep-ultraviolet (D-UV) regions, is of great significance due to its unique applications in secret communications and optics. However, it is still challenging to universally synthesize the corresponding metal nanostructures due to their high activity. Herein, we report a universal, eco-friendly, facile and rapid synthesis of various nano-metals encapsulated by ultrathin carbon shells, significantly with a remarkable deep-UV LSPR characteristic, via a liquid-phase laser fabrication method. Firstly, a new generation of the laser ablation in liquid (LAL) method has been developed with an emphasis on the elaborate selection of solvents to generate ultrathin carbon shells, and hence to stabilize the formed metal nanocrystals. As a result, a series of metal@carbon nanoparticles (NPs), including Cr@C, Ti@C, Fe@C, V@C, Al@C, Sn@C, Mn@C and Pd@C, can be fabricated by this modified LAL method. Interestingly, these NPs exhibit LSPR peaks in the range of 200-330 nm, which are very rare for localized surface plasmon resonance. Consequently, the UV plasmonic effects of these metal@carbon NPs were demonstrated both by the observed enhancement in UV photoluminescence (PL) from the carbon nanoshells and by the improvement of the photo-responsivity of UV GaN photodetectors. This work could provide a universal method for carbon shelled metal NPs and expand plasmonics into the D-UV waveband.

Comparison of Jacket Production Processes Designed by Fabric Materials and Leather

Directory of Open Access Journals (Sweden)

Emine Utkun

2011-02-01

Full Text Available Leather and leather products industry has shown a significant improvement in export area, as a result of intensive shuttle trades and demand that comes from crumbling Eastern Bloc countries in 1990's. This development has caused capacity increasing and thus makes large investments in this sector. Leather garment industry differs from woven or fabrics industry at various points. Differantation seems in raw materials features such as size, thickness, biological, chemical or physical homogenity. Due to the natural structure, leather shows different attributes in different regions. This study examines the diversity of production processes of leather and fabric designed jacket.

[Research progress in CoCr metal-ceramic alloy fabricated by selective laser melting].

Science.gov (United States)

Yan, X; Lin, H

2018-02-09

Cobalt-chromium alloys have been applied to dental porcelain fused to metal (PFM) restorations over the past decades owing to their excellent corrosion resistance, good biocompatibility and low price. The production of CoCr metal-ceramic restorations has always been based on traditional lost-wax casting techniques. However, in recent years, selective laser melting (SLM) is becoming more and more highly valued by dental laboratories and dental practitioners due to its individuation, precision and efficiency. This paper mainly reviews the recent researches on the production process of copings, microstructure, mechanical property, metal-ceramic bond strength, fit of copings, corrosion resistance and biocompatibility of SLM CoCr metal-ceramic alloy.

Method of fabricating zirconium metal for use in composite type fuel cans

International Nuclear Information System (INIS)

Imahashi, Hiromichi; Inagaki, Masatoshi; Akabori, Kimihiko; Tada, Naofumi; Yasuda, Tetsuro.

1985-01-01

Purpose: To mass produce zirconium metal for fuel cans with less radiation hardening. Method: Zirconium sponges as raw material are inserted in a hearth mold and a procedure of melting the zirconium sponges portionwise by using a melting furnace having electron beams as a heat source while moving the hearth is repeated at least for once. Then, the rod-like ingot after melting is melted again in a vacuum or inert gas atmosphere into an ingot of a low oxygen density capable of fabrication. A composite fuel can billet is formed by using the thus obtained zirconium ingot and a zircalloy, and a predetermined composite type fuel can is manufactured by way of hot extrusion and pipe drawing fabrication. The raw material usable herein is zirconium sponge with an oxygen density of 400 ppm or higher and the content of impurity other than oxygen is between 1000 - 5000 ppm in total, or the molten material thereof. (Kamimura, M.)

Fabrication of three-dimensional freestanding metal micropipes for microfluidics and microreaction technology

International Nuclear Information System (INIS)

Lang, P; Neiß, S; Woias, P

2011-01-01

In this paper, we describe a simple and novel fabrication process to produce three-dimensional freestanding metal micropipes. This process is based on conventional micromachining and electroless nickel plating inside a microfluidic channel of structured and stacked silicon substrates. The nickel micropipe resists an etching with KOH, which facilitates to fabricate freestanding, functional micropipes. The in-channel electroless plating achieves a continuous and homogeneous deposition of nickel and shows an accurate coating of small microstructures down to 20 µm. Furthermore, the deposited nickel layers possess a high tensile strength for bonding (>200–300 N mm −2 ), are chemically inert against fluorine gas and withstand pressures up to 6 bar. Thermal measurements have shown that released micropipes show better heat flux densities than embedded micropipes with 86% at a cooling flow rate of 16 ml h −1 . Hence, released micropipes feature accurate control of the temperature in the micropipe via a variance of the cooling fluid flow rate.

Principles and practices of lean production applied in a metal structures production system

OpenAIRE

Carvalho, Rogério; Alves, Anabela Carvalho; Lopes, Isabel da Silva

2011-01-01

This paper presents a work undertaken in a metal structures production system in a company producing several assorted products for the civil construction. The work aim was to improve the production process, solving several productive problems encountered in the production system, such as: deliveries delays, long lead times, too many material handling, high stocks, errors and defects in metal structures assembly and production, and unnecessary motions. The identified problems were analyzed and...

Marginal discrepancy of noble metal-ceramic fixed dental prosthesis frameworks fabricated by conventional and digital technologies.

Science.gov (United States)

Afify, Ahmed; Haney, Stephan; Verrett, Ronald; Mansueto, Michael; Cray, James; Johnson, Russell

2018-02-01

Studies evaluating the marginal adaptation of available computer-aided design and computer-aided manufacturing (CAD-CAM) noble alloys for metal-ceramic prostheses are lacking. The purpose of this in vitro study was to evaluate the vertical marginal adaptation of cast, milled, and direct metal laser sintered (DMLS) noble metal-ceramic 3-unit fixed partial denture (FDP) frameworks before and after fit adjustments. Two typodont teeth were prepared for metal-ceramic FDP abutments. An acrylic resin pattern of the prepared teeth was fabricated and cast in nickel-chromium (Ni-Cr) alloy. Each specimen group (cast, milled, DMLS) was composed of 12 casts made from 12 impressions (n=12). A single design for the FDP substructure was created on a laboratory scanner and used for designing the specimens in the 3 groups. Each specimen was fitted to its corresponding cast by using up to 5 adjustment cycles, and marginal discrepancies were measured on the master Ni-Cr model before and after laboratory fit adjustments. The milled and DMLS groups had smaller marginal discrepancy measurements than those of the cast group (PDMLS and cast groups (F=30.643, P<.001). Metal-ceramic noble alloy frameworks fabricated by using a CAD-CAM workflow had significantly smaller marginal discrepancies compared with those with a traditional cast workflow, with the milled group demonstrating the best marginal fit among the 3 test groups. Manual refining significantly enhanced the marginal fit of all groups. All 3 groups demonstrated marginal discrepancies within the range of clinical acceptability. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Problems of zirconium metal production in Czechoslovakia

International Nuclear Information System (INIS)

Vareka, J.; Vaclavik, E.

1975-01-01

The problems are summed up of the production and quality control of zirconium sponge. A survey is given of industrial applications of zirconium in form of pure metal or alloys in nuclear power production, ferrous and non-ferrous metallurgy, chemical engineering and electrical engineering. A survey is also presented of the manufacture of zirconium metal in advanced capitalist countries. (J.B.)

Fabrication and characterization of metal-packaged fiber Bragg grating sensor by one-step ultrasonic welding

Science.gov (United States)

Zhang, Yumin; Zhu, Lianqing; Luo, Fei; Dong, Mingli; Ding, Xiangdong; He, Wei

2016-06-01

A metallic packaging technique of fiber Bragg grating (FBG) sensors is developed for measurement of strain and temperature, and it can be simply achieved via one-step ultrasonic welding. The average strain transfer rate of the metal-packaged sensor is theoretically evaluated by a proposed model aiming at surface-bonded metallic packaging FBG. According to analytical results, the metallic packaging shows higher average strain transfer rate compared with traditional adhesive packaging under the same packaging conditions. Strain tests are performed on an elaborate uniform strength beam for both tensile and compressive strains; strain sensitivities of approximately 1.16 and 1.30 pm/μɛ are obtained for the tensile and compressive situations, respectively. Temperature rising and cooling tests are also executed from 50°C to 200°C, and the sensitivity of temperature is 36.59 pm/°C. All the measurements of strain and temperature exhibit good linearity and stability. These results demonstrate that the metal-packaged sensors can be successfully fabricated by one-step welding technique and provide great promise for long-term and high-precision structural health monitoring.

Effect of repeated ceramic firings on the marginal and internal adaptation of metal-ceramic restorations fabricated with different CAD-CAM technologies.

Science.gov (United States)

Kocaağaoğlu, Hasan; Albayrak, Haydar; Kilinc, Halil Ibrahim; Gümüs, Hasan Önder

2017-11-01

The use of computer-aided design and computer-aided manufacturing (CAD-CAM) for metal-ceramic restorations has increased with advances in the technology. However, little is known about the marginal and internal adaptation of restorations fabricated using laser sintering (LS) and soft milling (SM). Moreover, the effects of repeated ceramic firings on the marginal and internal adaptation of metal-ceramic restorations fabricated with LS and SM is also unknown. The purpose of this in vitro study was to investigate the effects of repeated ceramic firings on the marginal and internal adaptation of metal-ceramic copings fabricated using the lost wax (LW), LS, and SM techniques. Ten LW, 10 LS, and 10 SM cobalt-chromium (Co-Cr) copings were fabricated for an artificial tooth (Frasaco GmbH). After the application of veneering ceramic (VITA VMK Master; VITA Zahnfabrik), the marginal and internal discrepancies of these copings were measured with a silicone indicator paste and a stereomicroscope at ×100 magnification after the first, second, and third clinical simulated ceramic firing cycles. Repeated measures 2-way ANOVA and the Fisher LSD post hoc test were used to evaluate differences in marginal and internal discrepancies (α=.05). Neither fabrication protocol nor repeated ceramic firings had any statistically significant effect on internal discrepancy values (P>.05). Marginal discrepancy values were also statistically unaffected by repeated ceramic firings (P>.05); however, the fabrication protocol had a significant effect on marginal discrepancy values (Pmarginal discrepancy values than LS or SM (PMarginal discrepancy values did not vary between LS and SM (P>.05). All groups demonstrated clinically acceptable marginal adaptation after repeated ceramic firing cycles; however, the LS and SM groups demonstrated better marginal adaptation than that of LW group and may be appropriate clinical alternatives to LW. Copyright © 2017 Editorial Council for the Journal of

Commercial production of metal hafnium and hafnium-based products

International Nuclear Information System (INIS)

Negodin, D.A.; Shtutsa, M.G.; Akhtonov, S.G.; Il'enko, E.V.; Kobyzev, A.M.

2012-01-01

Hafnium possesses a unique complex of physical and chemical properties which allow the application of products on its basis in various industries. Joint Stock Company 'Chepetsky Mechanical Plant' is the single enterprise which produces hafnium on the territory of Russia. The manufacture of metal hafnium with the total content of zirconium and hafnium, at least, 99,8 % of weights is developed at the present time at Joint Stock Company CHMZ. The weight of melted hafnium ingots is up to 1 ton. Manufacture of wide range of products from hafnium is implemented. The plates from a hafnium with thickness of 0.60 mm which are used for emergency control cartridges of VVER-440 reactors are the most critical product. It is shown that ingots and products obtained from metal hafnium correspond to the Russian and international standards for reactor materials in chemical composition, mechanical and corrosion properties.

Inherent health and environmental risk assessment of nanostructured metal oxide production processes.

Science.gov (United States)

Torabifard, Mina; Arjmandi, Reza; Rashidi, Alimorad; Nouri, Jafar; Mohammadfam, Iraj

2018-01-10

The health and environmental effects of chemical processes can be assessed during the initial stage of their production. In this paper, the Chemical Screening Tool for Exposure and Environmental Release (ChemSTEER) software was used to compare the health and environmental risks of spray pyrolysis and wet chemical techniques for the fabrication of nanostructured metal oxide on a semi-industrial scale with a capacity of 300 kg/day in Iran. The pollution sources identified in each production process were pairwise compared in Expert Choice software using indicators including respiratory damage, skin damage, and environmental damages including air, water, and soil pollution. The synthesis of nanostructured zinc oxide using the wet chemical technique (with 0.523 wt%) leads to lower health and environmental risks compared to when spray pyrolysis is used (with 0.477 wt%). The health and environmental risk assessment of nanomaterial production processes can help select safer processes, modify the operation conditions, and select or modify raw materials that can help eliminate the risks.

THE MINING ACTIVITIES AND THE METAL PRODUCTION IN ARYCANDA IN LYCIA

OpenAIRE

B.S. Alptekin Oransay

2012-01-01

Arycanda lies in eastern Lycia, which is in 35.th km of the modern Elmalı – Finike highway. During the excavations since 1971, there were found so many metal artifacts and metal slags especially from the late Roman layers in the city. These finds revealed that there was a specific metal production in Arykanda. This production covers not only the tool production from pure metal, but also includes metal purification process around the city. This metal production industry of Arykanda adds so man...

Structural Engineering of Metal-Mesh Structure Applicable for Transparent Electrodes Fabricated by Self-Formable Cracked Template

Directory of Open Access Journals (Sweden)

Yeong-gyu Kim

2017-08-01

Full Text Available Flexible and transparent conducting electrodes are essential for future electronic devices. In this study, we successfully fabricated a highly-interconnected metal-mesh structure (MMS using a self-formable cracked template. The template—fabricated from colloidal silica—can be easily formed and removed, presenting a simple and cost-effective way to construct a randomly and uniformly networked MMS. The structure of the MMS can be controlled by varying the spin-coating speed during the coating of the template solution or by stacking of metal-mesh layers. Through these techniques, the optical transparency and sheet resistance of the MMS can be designed for a specific purpose. A double-layered Al MMS showed high optical transparency (~80% in the visible region, low sheet resistance (~20 Ω/sq, and good flexibility under bending test compared with a single-layered MMS, because of its highly-interconnected wire structure. Additionally, we identified the applicability of the MMS in the case of practical devices by applying it to electrodes of thin-film transistors (TFTs. The TFTs with MMS electrodes showed comparable electrical characteristics to those with conventional film-type electrodes. The cracked template can be used for the fabrication of a mesh structure consisting of any material, so it can be used for not only transparent electrodes, but also various applications such as solar cells, sensors, etc.

Recovery of noble metals from fission products

International Nuclear Information System (INIS)

Jenson, G.A.; Platt, A.M.; Mellinger, G.B.; Bjorklund, W.J.

1982-11-01

Scoping studies were started in 1979 to develop a cost-effective, waste-management-compatible process to extract noble metals from fission products. The process, involving the reaction with glassmelting chemicals, a metal oxide (PbO), and a reducing agent (charcoal), was demonstrated for recovering noble metals from simulated high-level waste oxides. The process has now been demonstrated on a laboratory scale (100 g) using irradiated fuels. Recoveries in the recovered lead averaged 80% for Pd, 60% for Rh, and 14% Ru. The resulting glass product was homogeneous in appearance, and the chemical durability was comparable to other waste oxides

Production of Plutonium Metal from Aqueous Solutions

Energy Technology Data Exchange (ETDEWEB)

Orth, D.A.

2003-01-16

The primary separation of plutonium from irradiated uranium by the Purex solvent extraction process at the Savannah River Plant produces a dilute plutonium solution containing residual fission products and uranium. A cation exchange process is used for concentration and further decontamination of the plutonium, as the first step in the final preparation of metal. This paper discusses the production of plutonium metal from the aqueous solutions.

Comparative Study of Laboratory-Scale and Prototypic Production-Scale Fuel Fabrication Processes and Product Characteristics

International Nuclear Information System (INIS)

2014-01-01

An objective of the High Temperature Gas Reactor fuel development and qualification program for the United States Department of Energy has been to qualify fuel fabricated in prototypic production-scale equipment. The quality and characteristics of the tristructural isotropic coatings on fuel kernels are influenced by the equipment scale and processing parameters. Some characteristics affecting product quality were suppressed while others have become more significant in the larger equipment. Changes to the composition and method of producing resinated graphite matrix material has eliminated the use of hazardous, flammable liquids and enabled it to be procured as a vendor-supplied feed stock. A new method of overcoating TRISO particles with the resinated graphite matrix eliminates the use of hazardous, flammable liquids, produces highly spherical particles with a narrow size distribution, and attains product yields in excess of 99%. Compact fabrication processes have been scaled-up and automated with relatively minor changes to compact quality to manual laboratory-scale processes. The impact on statistical variability of the processes and the products as equipment was scaled are discussed. The prototypic production-scale processes produce test fuels that meet fuel quality specifications.

Trace metal contents in barbeque (BBQ) charcoal products

Energy Technology Data Exchange (ETDEWEB)

Kabir, Ehsanul [Department of Environment and Energy, Sejong University, 98 Goon Ja Dong, Seoul 143-747 (Korea, Republic of); Kim, Ki-Hyun, E-mail: khkim@sejong.ac.kr [Department of Environment and Energy, Sejong University, 98 Goon Ja Dong, Seoul 143-747 (Korea, Republic of); Yoon, H.O. [Korea Basic Science Institute, Seoul Center, Seoul 136-701 (Korea, Republic of)

2011-01-30

In this study, the concentrations of trace elements contained in solid barbeque (BBQ) charcoal products have been investigated. Eleven brands of charcoal products were analyzed, consisting of both Korean (3 types) and imported products (eight types from three countries) commonly available in the Korean market places. The concentrations of trace metals in solid charcoal varied widely across metal types and between samples with the overall range of 5 {mu}g kg{sup -1} (As) to 118 mg kg{sup -1} (Zn). The patterns of metal distribution between different products appeared to be affected by the properties of raw materials and/or the processes involved in their production. Although concentrations of certain trace metals were significantly high in certain charcoal samples, their emission concentrations were below legislative guidelines (e.g., the permissible exposure limit (PEL) set by the Occupational Safety and Health Administration (OSHA)). In light of the potential harm of grilling activities, proper regulation should be considered to control the use of BBQ charcoal from a toxicological viewpoint to help reduce the potential health risks associated with its use.

Trace metal contents in barbeque (BBQ) charcoal products

International Nuclear Information System (INIS)

Kabir, Ehsanul; Kim, Ki-Hyun; Yoon, H.O.

2011-01-01

In this study, the concentrations of trace elements contained in solid barbeque (BBQ) charcoal products have been investigated. Eleven brands of charcoal products were analyzed, consisting of both Korean (3 types) and imported products (eight types from three countries) commonly available in the Korean market places. The concentrations of trace metals in solid charcoal varied widely across metal types and between samples with the overall range of 5 μg kg -1 (As) to 118 mg kg -1 (Zn). The patterns of metal distribution between different products appeared to be affected by the properties of raw materials and/or the processes involved in their production. Although concentrations of certain trace metals were significantly high in certain charcoal samples, their emission concentrations were below legislative guidelines (e.g., the permissible exposure limit (PEL) set by the Occupational Safety and Health Administration (OSHA)). In light of the potential harm of grilling activities, proper regulation should be considered to control the use of BBQ charcoal from a toxicological viewpoint to help reduce the potential health risks associated with its use.

Testing the electrostatic characteristics of polypropylene fabric with metallic yarns, intended for use in coal mines threatened by the explosion hazard. Part 2: Tests in coal mine

International Nuclear Information System (INIS)

Talarek, M; Orzech, L

2011-01-01

The aim of this paper was to assess the electrostatic safety of polypropylene fabric with metallic yarns intended for use in coal mines. Such fabrics have not been used in the Polish mining industry yet. The tests conducted have been divided into two subgroups: laboratory tests and tests in a coal mine. This paper presents the results of tests in a coal mine, where we have focused on the resistance-to-ground in some specific situations. Bags made of fabric at the roadway face were tested, as well as the roll of fabric during transport and carried by a miner. The results obtained allow the reliable assessment of the risk of using fabrics with metallic yarns in the explosive atmosphere which often occurs in coal mines.

Electrophoretic Deposition for the Fabrication of High-Performance Metal-Ceramic Hybrid Cladding

International Nuclear Information System (INIS)

Park, Junghwan; Jung, Yangil; Park, Dongjun; Kim, Hyungil; Park, Jeongyong; Koo, Yanghyun

2014-01-01

Metal-ceramic hybrid cladding consisting of a Zr liner and SiC f /SiC composite is one of the candidate systems. To achieve a high-performance metal-ceramic hybrid cladding, it is important to synthesize the SiC f /SiC composites with high flexural strength. The most common interphases, such as pyrolytic carbon (PyC) and boron nitride (BN) coating, have been applied on the surface of SiC fibers by chemical vapor deposition (CVD) or chemical vapor infiltration (CVI). In addition, the SiC matrix phase for SiC f /SiC composites has been commonly formed by CVI and polymer infiltration and pyrolysis (PIP), which are very costly and complicated processes. For this reason, the fabrication process of SiC f /SiC composites that is low-cost and simple has been strongly needed. In this study, weak phase coating using a commercial colloidal carbon black suspension was performed on SiC fibers through electrophoretic deposition (EPD), and carbon-coated SiC f /SiC composites were fabricated by EPD. The mechanical properties at room temperature were evaluated to investigate the effect of the carbon interfacial layer on the mechanical properties of carbon-coated SiC f /SiC composites. In this study, it was concluded that the EPD method is effective for homogeneous carbon black coating on SiC fibers, and that the carbon coating layer on SiC fibers plays an important role in optimizing the interface between fibers and the matrix, and enhances the toughness of carbon-coated SiC f /SiC composites during fracture

Manufacturing processes in the textile industry. Expert Systems for fabrics production

OpenAIRE

Bullon, Juan; González Arrieta, Angélica; Hernández Encinas, Ascensión; Queiruga Dios, Araceli

2017-01-01

The textile industry is characterized by the economic activity whose objective is the production of fibres, yarns, fabrics, clothing and textile goods for home and decoration,as well as technical and industrial purposes. Within manufacturing, the Textile is one of the oldest and most complex sectors which includes a large number of sub-sectors covering the entire production cycle, from raw materials and intermediate products, to the production of final products. Textile industry activities pr...

Clinical acceptability of metal-ceramic fixed partial dental prosthesis fabricated with direct metal laser sintering technique-5 year follow-up.

Science.gov (United States)

Prabhu, Radhakrishnan; Prabhu, Geetha; Baskaran, Eswaran; Arumugam, Eswaran M

2016-01-01

In recent years, direct metal laser sintered (DMLS) metal-ceramic-based fixed partial denture prostheses have been used as an alternative to conventional metal-ceramic fixed partial denture prostheses. However, clinical studies for evaluating their long-term clinical survivability and acceptability are limited. The aim of this study was to assess the efficacy of metal-ceramic fixed dental prosthesis fabricated with DMLS technique, and its clinical acceptance on long-term clinical use. The study group consisted of 45 patients who were restored with posterior three-unit fixed partial denture prosthesis made using direct laser sintered metal-ceramic restorations. Patient recall and clinical examination of the restorations were done after 6months and every 12 months thereafter for the period of 60 months. Clinical examination for evaluation of longevity of restorations was done using modified Ryge criteria which included chipping of the veneered ceramic, connector failure occurring in the fixed partial denture prosthesis, discoloration at the marginal areas of the veneered ceramic, and marginal adaptation of the metal and ceramic of the fixed denture prosthesis. Periapical status was assessed using periodical radiographs during the study period. Survival analysis was made using the Kaplan-Meier method. None of the patients had failure of the connector of the fixed partial denture prostheses during the study period. Two exhibited biological changes which included periapical changes and proximal caries adjacent to the abutments. DMLS metal-ceramic fixed partial denture prosthesis had a survival rate of 95.5% and yielded promising results during the 5-year clinical study.

Roll-to-Roll Nanoforming of Metals Using Laser-Induced Superplasticity.

Science.gov (United States)

Goswami, Debkalpa; Munera, Juan C; Pal, Aniket; Sadri, Behnam; Scarpetti, Caio Lui P G; Martinez, Ramses V

2018-05-24

This Letter describes a low-cost, scalable nanomanufacturing process that enables the continuous forming of thin metallic layers with nanoscale accuracy using roll-to-roll, laser-induced superplasticity (R2RLIS). R2RLIS uses a laser shock to induce the ultrahigh-strain-rate deformation of metallic films at room temperature into low-cost polymeric nanomolds, independently of the original grain size of the metal. This simple and inexpensive nanoforming method does not require access to cleanrooms and associated facilities, and can be easily implemented on conventional CO 2 lasers, enabling laser systems commonly used for rapid prototyping or industrial cutting and engraving to fabricate uniform and three-dimensional crystalline metallic nanostructures over large areas. Tuning the laser power during the R2RLIS process enables the control of the aspect ratio and the mechanical and optical properties of the fabricated nanostructures. This roll-to-roll technique successfully fabricates mechanically strengthened gold plasmonic nanostructures with aspect ratios as high as 5 that exhibit high oxidation resistance and strong optical field enhancements. The CO 2 laser used in R2RLIS can also integrate the fabricated nanostructures on transparent flexible substrates with robust interfacial contact. The ability to fabricate ultrasmooth metallic nanostructures using roll-to-roll manufacturing enables the large scale production, at a relatively low-cost, of flexible plasmonic devices toward emerging applications.

Fabrication of High Temperature Cermet Materials for Nuclear Thermal Propulsion

Science.gov (United States)

Hickman, Robert; Panda, Binayak; Shah, Sandeep

2005-01-01

Processing techniques are being developed to fabricate refractory metal and ceramic cermet materials for Nuclear Thermal Propulsion (NTP). Significant advances have been made in the area of high-temperature cermet fuel processing since RoverNERVA. Cermet materials offer several advantages such as retention of fission products and fuels, thermal shock resistance, hydrogen compatibility, high conductivity, and high strength. Recent NASA h d e d research has demonstrated the net shape fabrication of W-Re-HfC and other refractory metal and ceramic components that are similar to UN/W-Re cermet fuels. This effort is focused on basic research and characterization to identify the most promising compositions and processing techniques. A particular emphasis is being placed on low cost processes to fabricate near net shape parts of practical size. Several processing methods including Vacuum Plasma Spray (VPS) and conventional PM processes are being evaluated to fabricate material property samples and components. Surrogate W-Re/ZrN cermet fuel materials are being used to develop processing techniques for both coated and uncoated ceramic particles. After process optimization, depleted uranium-based cermets will be fabricated and tested to evaluate mechanical, thermal, and hot H2 erosion properties. This paper provides details on the current results of the project.

Noble-metal nanoparticles produced with colloidal lithography: fabrication, optical properties and applications

Energy Technology Data Exchange (ETDEWEB)

Bocchio, Noelia Laura

2008-08-15

In this work, metal nanoparticles produced by nanosphere lithography were studied in terms of their optical properties (in connection to their plasmon resonances), their potential application in sensing platforms - for thin layer sensing and bio-recognition events -, and for a particular case (the nanocrescents), for enhanced spectroscopy studies. The general preparation procedures introduced early in 2005 by Shumaker-Parry et al. to produce metallic nanocrescents were extended to give rise to more complex (isolated) structures, and also, by combining colloidal monolayer fabrication and plasma etching techniques, to arrays of them. The fabrication methods presented in this work were extended not only to new shapes or arrangements of particles, but included also a targeted surface tailoring of the substrates and the structures, using different thiol and silane compounds as linkers for further attachment of, i.e. polyelectrolyte layers, which allow for a controlled tailoring of their nanoenvironment. The optical properties of the nanocrescents were studied with conventional transmission spectroscopy; a simple multipole model was adapted to explain their behaviour qualitatively. In terms of applications, the results on thin film sensing using these particles show that the crescents present an interesting mode-dependent sensitivity and spatial extension. Parallel to this, the penetrations depths were modeled with two simplified schemes, obtaining good agreement with theory. The multiple modes of the particles with their characteristic decay lengths and sensitivities represent a major improvement for particle-sensing platforms compared to previous single resonance systems. The nanocrescents were also used to alter the emission properties of fluorophores placed close to them. In this work, green emitting dyes were placed at controlled distances from the structures and excited using a pulsed laser emitting in the near infrared. The fluorescence signal obtained in this

Fabrication and characterisation of embedded metal nanostructures by ion implantation with nanoporous anodic alumina masks

Energy Technology Data Exchange (ETDEWEB)

Guan, Wei [NanoLAB, Department of Materials Science and Engineering, University of Sheffield, Sheffield S1 3JD (United Kingdom); School of Physics and Astronomy, University of Edinburgh, Mayfield Road, Edinburgh EH9 3JZ (United Kingdom); Peng, Nianhua, E-mail: n.peng@surrey.ac.uk [Surrey Ion Beam Centre, Surrey University, Guildford GU2 7XH (United Kingdom); Jeynes, Christopher [Surrey Ion Beam Centre, Surrey University, Guildford GU2 7XH (United Kingdom); Ghatak, Jay [NanoLAB, Department of Materials Science and Engineering, University of Sheffield, Sheffield S1 3JD (United Kingdom); Peng, Yong [NanoLAB, Department of Materials Science and Engineering, University of Sheffield, Sheffield S1 3JD (United Kingdom); School of Physical Science and Technology, Lanzhou University, 222 Tianshui Road, Lanzhou 730000 (China); Ross, Ian M. [Department of Electronic and Electric Engineering, University of Sheffield, Sheffield S1 3JD (United Kingdom); Bhatta, Umananda M.; Inkson, Beverley J.; Möbus, Günter [NanoLAB, Department of Materials Science and Engineering, University of Sheffield, Sheffield S1 3JD (United Kingdom)

2013-07-15

Lateral ordered Co, Pt and Co/Pt nanostructures were fabricated in SiO{sub 2} and Si{sub 3}N{sub 4} substrates by high fluence metal ion implantation through periodic nanochannel membrane masks based on anodic aluminium oxides (AAO). The quality of nanopatterning transfer defined by various AAO masks in different substrates was examined by transmission electron microscopy (TEM) in both imaging and spectroscopy modes.

Low-loss integrated electrical surface plasmon source with ultra-smooth metal film fabricated by polymethyl methacrylate ‘bond and peel’ method

Science.gov (United States)

Liu, Wenjie; Hu, Xiaolong; Zou, Qiushun; Wu, Shaoying; Jin, Chongjun

2018-06-01

External light sources are mostly employed to functionalize the plasmonic components, resulting in a bulky footprint. Electrically driven integrated plasmonic devices, combining ultra-compact critical feature sizes with extremely high transmission speeds and low power consumption, can link plasmonics with the present-day electronic world. In an effort to achieve this prospect, suppressing the losses in the plasmonic devices becomes a pressing issue. In this work, we developed a novel polymethyl methacrylate ‘bond and peel’ method to fabricate metal films with sub-nanometer smooth surfaces on semiconductor wafers. Based on this method, we further fabricated a compact plasmonic source containing a metal-insulator-metal (MIM) waveguide with an ultra-smooth metal surface on a GaAs-based light-emitting diode wafer. An increase in propagation length of the SPP mode by a factor of 2.95 was achieved as compared with the conventional device containing a relatively rough metal surface. Numerical calculations further confirmed that the propagation length is comparable to the theoretical prediction on the MIM waveguide with perfectly smooth metal surfaces. This method facilitates low-loss and high-integration of electrically driven plasmonic devices, thus provides an immediate opportunity for the practical application of on-chip integrated plasmonic circuits.

A comparative study of nitride purity and Am fabrication losses in PuN materials by the powder and internal gelation production routes

Energy Technology Data Exchange (ETDEWEB)

Hedberg, Marcus, E-mail: marhed@chalmers.se; Ekberg, Christian

2016-12-15

Fabrication of plutonium containing fuels through the internal gelation method has mostly been studied in mixed metal systems such as U, Pu or Zr,Pu. In this work production of undiluted PuN has been performed by carbothermal reduction on both oxide powder and Pu microspheres produced by the internal gelation method. Nitride purities reached using the different methods have been studied together with final densities achieved during pellet fabrication as well as losses of ingrown Am during the different production steps. Formation of Pu microspheres was successfully performed using the internal gelation method, although extensive microsphere fracturing occurred during thermal treatment. Final densities of PuN pellets produced by cold pressing and sintering reached 70–80% of theoretical density. Am losses during the carbothermal reduction step was on average about 3.7%. After sintering about 11% of Am was lost in total through the entire production process if sintering in N{sub 2} + 5% H{sub 2} atmosphere while about 50% of the Am in total was lost when using Ar as sintering atmosphere. - Highlights: • Internal gelation Pu based sols was performed. • Nitride formation by carbothermal reduction on Pu microspheres and powders was performed. • Pelletization and sintering of pellets was performed. • Am losses were measured throughout the production steps.

Fabrication of magnetic nano liquid metal fluid through loading of Ni nanoparticles into gallium or its alloy

Energy Technology Data Exchange (ETDEWEB)

Xiong, Mingfeng; Gao, Yunxia [Key Lab of Cryogenics and Beijing Key Lab of CryoBiomedical Engineering, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Liu, Jing, E-mail: jliu@mail.ipc.ac.cn [Key Lab of Cryogenics and Beijing Key Lab of CryoBiomedical Engineering, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing 100084 (China)

2014-03-15

In this study, Ni nanoparticles were loaded into the partially oxidized gallium and its alloys to fabricate desired magnetic nanofluid. It was disclosed that the Ni nanoparticles sharply increased the freezing temperature and latent heat of the obtained magnetic nano liquid metal fluid, while the melting process was less affected. For the gallium sample added with 10 vol% coated Ni particles, a hysteresis loop was observed and the magnetization intensity decreased with the increase of the temperature. The slope for the magnetization-temperature curve within 10–30 K was about 20 times of that from 40 K to 400 K. Further, the dynamic impact experiments of striking magnetic liquid metal droplets on the magnet revealed that the regurgitating of the leading edge of the liquid disk and the subsequent wave that often occurred in the gallium-indium droplets would disappear for the magnetic fluids case due to attraction force of the magnet. - Graphical abstract: High speed videos for the impact of striking GaIn{sub 24.5} based magnetic liquid metal droplets on a magnet plate. - Highlights: • A feasible way to fabricate magnetic nano liquid metal fluid was presented. • Ni nanoparticles sharply increased freezing temperature and latent heat of magnetic nanofluid. • A hysteresis loop phenomenon was observed for the magnetic nanofluid. • Temperature dependent magnetization spanning from 10 K to 400 K was measured. • Impact phenomena of striking magnetic droplets on magnet were disclosed.

Fabrication of a metal-free ceramic restoration utilizing the monobloc technique.

Science.gov (United States)

Pissis, P

1995-01-01

This article presents a new technique which utilizes a porcelain core/crown unit, fabricated in the laboratory as a single component. The monobloc technique was developed by the author to replace the traditional metal post and core which prevents the transmission of light through porcelain crowns, creating a dark color effect. Between 1989 and 1992, a number of cases were successfully treated with several variations of the monobloc technique. Approximately 50 cases were completed with vitro-ceramic and followed up. The learning objective of this article is to introduce this novel technique. The article discusses the development of the technique, its advantages, disadvantages, and the potential failures. The clinical procedure is illustrated with several case presentations.

Development and fabrication of seamless Aluminium finned clad tubes for metallic uranium fuel rods for research reactor

International Nuclear Information System (INIS)

Singh, A.K.; Hussain, M.M.; Jayachandran, N.K.; Abdulla, K.K.

2012-01-01

Natural uranium metal or its alloy is used as fuel in nuclear reactors. Usually fuel is clad with compatible material to prevent its direct contact with coolant which prevents spread of activity. One of the methods of producing fuel for nuclear reactor is by co-drawing finished uranium rods with aluminum clad tube to develop intimate contact for effective heat removal during reactor operation. Presently seam welded Aluminium tubes are used as clad for Research Reactor fuel. The paper will highlight entire fabrication process followed for the fabrication of seamless Aluminium finned tubes along with relevant characterisation results

Integration of Heat Treatment with Shot Peening of 17-4 Stainless Steel Fabricated by Direct Metal Laser Sintering

Science.gov (United States)

AlMangour, Bandar; Yang, Jenn-Ming

2017-11-01

Direct metal laser sintering (DMLS) is a promising powder-based additive manufacturing process for fabrication of near-net-shape parts. However, the typically poor fatigue performance of DMLS parts must be addressed for use in demanding industrial applications. Post-treatment can be applied to enhance the performance of such components. Earlier attempts at inducing grain refinement through severe plastic deformation of part surfaces using shot peening improved the physical and mechanical properties of metals without chemical alteration. However, heat treatment can modify the surface-hardening effects attained by shot peening. Hence, we examined the feasibility of applying shot peening combined with heat treatment to improve the performance of DMLS-fabricated 17-4 stainless steel parts through microstructural evolution studies and hardness measurements. Compared to a specimen treated only by shot peening, the sample exposed to additional heat treatment showed increased hardness due to aging of the dominant phase.

Innovative cellular distance structures from polymeric and metallic threads

Science.gov (United States)

Wieczorek, F.; Trümper, W.; Cherif, C.

2017-10-01

Knitting allows a high individual adaptability of the geometry and properties of flat-knitted spacer fabrics. This offers advantages for the specific adjustment of the mechanical properties of innovative composites based on highly viscous matrix systems such as bone cement, elastomer or foam and cellular reinforcing structures made from e. g. polymeric monofilaments or metallic wires. The prerequisite is the availability of binding solutions for highly productive production of functional, cellular, self-stabilized spacer flat knitted fabrics as supporting and functionalized structures.

Fabrication and Mechanical Properties of Silicon Carbide Micropillars

International Nuclear Information System (INIS)

Shin, Chan Sun; Jin, Hyung Ha; Kwon, Jun Hyun; Kim, Don Jin

2011-01-01

Silicon carbide (SiC) has outstanding thermal and mechanical properties under high temperature and high neutron irradiation. SiC and SiC/SiC composites have been proposed as a promising candidate material for structural components in fusion reactors. Characterization of the mechanical properties such as fracture strength is important in ensuring the reliability of these ceramic structures. This study demonstrates a micro-compression test of SiC micropillars which are fabricated by mask and dryetching technique. Our fabrication method involves lithographic pattering of spun and baked photoresist on chemically vapor-deposited (CVD) polycrystalline beta-SiC substrates, followed by lift-off process of electroplated metal into the prescribed photoresist template. This metal works as an etch cap for inductively coupled plasma (ICP) etching. Our fabrication method enables the production of more than a few hundred micropillars under an identical fabrication condition, which is a great benefit for the statistical analysis of the fracture properties of brittle ceramic materials. The diameters of fabricated SiC micropillars range from 6 down to 0.5 μm. The ratio of micropillar diameter to height is set to 1:3 ∼ 1:4. Uniaxial compression tests have been conducted using flat punch nanoindentation at room temperature. We observed the specimen size effect on the measured fracture stress of SiC micropillars. In this paper we present the results of the micro-compression tests of SiC micropillars with the diameters of 0.8 and 2.6 μm

Estimating product-to-product variations in metal forming using force measurements

NARCIS (Netherlands)

Havinga, Gosse Tjipke; Van Den Boogaard, Ton

2017-01-01

The limits of production accuracy of metal forming processes can be stretched by the development of control systems for compensation of product-to-product variations. Such systems require the use of measurements from each semi-finished product. These measurements must be used to estimate the final

Process for improving metal production in steelmaking processes

Science.gov (United States)

Pal, Uday B.; Gazula, Gopala K. M.; Hasham, Ali

1996-01-01

A process and apparatus for improving metal production in ironmaking and steelmaking processes is disclosed. The use of an inert metallic conductor in the slag containing crucible and the addition of a transition metal oxide to the slag are the disclosed process improvements.

A rapid process of Yba2Cu3O7-δ thin film fabrication using trifluoroacetate metal-organic deposition with polyethylene glycol additive

DEFF Research Database (Denmark)

Wu, Wei; Feng, Feng; Shi, Kai

2013-01-01

Trifluoroacetate metal-organic deposition (TFA-MOD) is a promising technique to fabricate YBa2Cu3O7-δ (YBCO) superconducting films. However, its slow pyrolysis process, which usually takes more than 10 h, constitutes a barrier for industrial production. In this study, polyethylene glycol (PEG......) was utilized to reduce the stress generation inside the coated films when the strong pyrolysis reactions happen. With the addition of 30 wt% PEG2000 to the precursor solution, a smooth film surface could be obtained through a rapid pyrolysis process of 15 min. After the optimizations of the crystallization...... and oxygenation processes, mass percentage and molecular weight of PEG additive, YBCO thin films with Jc of about 4.5 MA cm-2 (77 K, self-field) could be routinely fabricated using (20-30) wt% PEG(1000-2000) additive with a total treatment time of about 2 h including the 15 min pyrolysis process time. The effects...

Fabrication of preliminary fuel rods for SFR

International Nuclear Information System (INIS)

Kim, Sun Ki; Oh, Seok Jin; Ko, Young Mo; Woo, Youn Myung; Kim, Ki Hwan

2012-01-01

Metal fuels was selected for fueling many of the first reactors in the US, including the Experimental Breeder Reactor-I (EBR-I) and the Experimental Breeder Reactor-II (EBR-II) in Idaho, the FERMI-I reactor, and the Dounreay Fast Reactor (DFR) in the UK. Metallic U.Pu.Zr alloys were the reference fuel for the US Integral Fast Reactor (IFR) program. Metallic fuel has advantages such as simple fabrication procedures, good neutron economy, high thermal conductivity, excellent compatibility with a Na coolant and inherent passive safety. U-Zr-Pu alloy fuels have been used for SFR (sodium-cooled fast reactor) related to the closed fuel cycle for managing minor actinides and reducing a high radioactivity levels since the 1980s. Fabrication technology of metallic fuel for SFR has been in development in Korea as a national nuclear R and D program since 2007. For the final goal of SFR fuel rod fabrication with good performance, recently, three preliminary fuel rods were fabricated. In this paper, the preliminary fuel rods were fabricated, and then the inspection for QC(quality control) of the fuel rods was performed

Low Loss Advanced Metallic Fuel Casting Evaluation

International Nuclear Information System (INIS)

Kim, Kihwan; Ko, Youngmo; Kim, Jonghwan; Song, Hoon; Lee Chanbock

2014-01-01

The fabrication process for SFR fuel is composed of fuel slug casting, loading and fabrication of the fuel rods, and the fabrication of the final fuel assemblies. Fuel slug casting is the dominant source of fuel losses and recycles streams in the fabrication process. Recycle streams include fuel slug reworks, returned scraps, and fuel casting heels, which are a special concern in the counter gravity injection casting process because of the large masses involved. Large recycle and waste streams result in lowering the productivity and the economic efficiency of fuel production. To increase efficiency the fuel losses in the furnace chamber, crucible, and the mold, after casting a considerable amount of fuel alloy in the casting furnace, will be quantitatively evaluated. After evaluation the losses will be identified and minimized. It is expected that this study will contribute to the minimization of fuel losses and the wastes streams in the fabrication process of the fuel slugs. Also through this study the technical readiness level of the metallic fuel fabrication process will be further enhanced. In this study, U-Zr alloy system fuel slugs were fabricated by a gravity casting method. Metallic fuel slugs were successfully fabricated with 19 slugs/batch with diameter of 5mm and length of 300mm. Fuel losses was quantitatively evaluated in casting process for the fuel slugs. Fuel losses of the fuel slugs were so low, 0.1∼1.0%. Injection casting experiments have been performed to reduce the fuel loss and improve the casting method. U-Zr fuel slug having φ5.4-L250mm was soundly fabricated with 0.1% in fuel loss. The fuel losses could be minimized to 0.1%, which showed that casting technology of fuel slugs can be a feasible approach to reach the goal of the fuel losses of 0.1% or less in commercial scale

Production of pure metals

Science.gov (United States)

Philipp, W. H.; Marsik, S. J.; May, C. E. (Inventor)

1974-01-01

A process for depositing elements by irradiating liquids is reported. Ultra pure elements are precipitated from aqueous solutions or suspensions of compounds. A solution of a salt of a metal to be prepared is irradiated, and the insoluble reaction product settles out. Some chemical compounds may also be prepared in this manner.

Ultrafast Laser Engraving Method to Fabricate Gravure Plate for Printed Metal-Mesh Touch Panel

Directory of Open Access Journals (Sweden)

Weiyuan Chen

2015-10-01

Full Text Available In order to engrave gravure plate with fine lines structures, conventional art used lithography with dry/wet etching. Lithography with dry/wet etching method allows to engrave lines with smooth concave shape, but its disadvantages include difficulty in controlling aspect ratio, high and uniform in large size process, substrate material limitation due to etching solution availability, and process complexity. We developed ultra-fast laser technology to directly engrave a stainless plate, a gravure plate, to be used for fabricating 23 in. metal-mesh touch panel by gravure offset printing process. The technology employs high energy pulse to ablate materials from a substrate. Because the ultra-fast laser pulse duration is shorter than the energy dissipation time between material lattices, there is no heating issue during the ablation process. Therefore, no volcano-type protrusion on the engraved line edges occurs, leading to good printing quality. After laser engraving, we then reduce surface roughness of the gravure plate using electro-polishing process. Diamond like carbon (DLC coating layer is then added onto the surface to increase scratch resistance. We show that this procedure can fabricate gravure plate for gravure offset printing process with minimum printing linewidth 10.7 μm. A 23 in. metal-mesh pattern was printed using such gravure plate and fully functional touch panel was demonstrated in this work.

Fabrication of an artificial nanosucker device with a large area nanotube array of metallic glass.

Science.gov (United States)

Chen, Wei-Ting; Manivannan, Karthikeyan; Yu, Chia-Chi; Chu, Jinn P; Chen, Jem-Kun

2018-01-18

The concurrent attachment and detachment movements of geckos on virtually any type of surface via their foot pads have inspired us to develop a thermal device with numerous arrangements of a multi-layer thin film together with electrodes that can help modify the temperature of the surface via application of a voltage. A sequential fabrication process was employed on a large-scale integration to generate well-defined contact hole arrays of photoresist for use as templates on the electrode-based device. The photoresist templates were then subjected to sputter deposition of the metallic glass Zr 55 Cu 30 Al 10 Ni 5 . Consequently, a metallic glass nanotube (MGNT) array having a nominal wall thickness of 100 nm was obtained after removal of the photoresist template. When a water droplet was placed on the MGNT array, close nanochambers of metallic glass were formed. By applying voltage, the surface was heated to increase the pressure inside the nanochambers; this generated an expanding force that raised the droplet; thus, the static water contact angle (SWCA) was increased. In contrast, a sucking force was generated during surface cooling, which decreased the SWCA. Our fabrication strategy exploits the MGNT array surface as nanosuckers, which can mimic the climbing aptitude of geckos as they attach to (>10 N m -2 ) and detach from (0.26 N m -2 ) surfaces at 0.5 and 3 V of applied voltage, respectively. Thus, the climbing aptitude of geckos can be mimicked by employing the processing strategy presented herein for the development of artificial foot pads.

Electrophoretic Deposition for the Fabrication of High-Performance Metal-Ceramic Hybrid Cladding

Energy Technology Data Exchange (ETDEWEB)

Park, Junghwan; Jung, Yangil; Park, Dongjun; Kim, Hyungil; Park, Jeongyong; Koo, Yanghyun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2014-05-15

Metal-ceramic hybrid cladding consisting of a Zr liner and SiC{sub f}/SiC composite is one of the candidate systems. To achieve a high-performance metal-ceramic hybrid cladding, it is important to synthesize the SiC{sub f}/SiC composites with high flexural strength. The most common interphases, such as pyrolytic carbon (PyC) and boron nitride (BN) coating, have been applied on the surface of SiC fibers by chemical vapor deposition (CVD) or chemical vapor infiltration (CVI). In addition, the SiC matrix phase for SiC{sub f}/SiC composites has been commonly formed by CVI and polymer infiltration and pyrolysis (PIP), which are very costly and complicated processes. For this reason, the fabrication process of SiC{sub f}/SiC composites that is low-cost and simple has been strongly needed. In this study, weak phase coating using a commercial colloidal carbon black suspension was performed on SiC fibers through electrophoretic deposition (EPD), and carbon-coated SiC{sub f}/SiC composites were fabricated by EPD. The mechanical properties at room temperature were evaluated to investigate the effect of the carbon interfacial layer on the mechanical properties of carbon-coated SiC{sub f}/SiC composites. In this study, it was concluded that the EPD method is effective for homogeneous carbon black coating on SiC fibers, and that the carbon coating layer on SiC fibers plays an important role in optimizing the interface between fibers and the matrix, and enhances the toughness of carbon-coated SiC{sub f}/SiC composites during fracture.

CMOS MEMS Fabrication Technologies and Devices

Directory of Open Access Journals (Sweden)

Hongwei Qu

2016-01-01

Full Text Available This paper reviews CMOS (complementary metal-oxide-semiconductor MEMS (micro-electro-mechanical systems fabrication technologies and enabled micro devices of various sensors and actuators. The technologies are classified based on the sequence of the fabrication of CMOS circuitry and MEMS elements, while SOI (silicon-on-insulator CMOS MEMS are introduced separately. Introduction of associated devices follows the description of the respective CMOS MEMS technologies. Due to the vast array of CMOS MEMS devices, this review focuses only on the most typical MEMS sensors and actuators including pressure sensors, inertial sensors, frequency reference devices and actuators utilizing different physics effects and the fabrication processes introduced. Moreover, the incorporation of MEMS and CMOS is limited to monolithic integration, meaning wafer-bonding-based stacking and other integration approaches, despite their advantages, are excluded from the discussion. Both competitive industrial products and state-of-the-art research results on CMOS MEMS are covered.

Nonvacuum, maskless fabrication of a flexible metal grid transparent conductor by low-temperature selective laser sintering of nanoparticle ink.

Science.gov (United States)

Hong, Sukjoon; Yeo, Junyeob; Kim, Gunho; Kim, Dongkyu; Lee, Habeom; Kwon, Jinhyeong; Lee, Hyungman; Lee, Phillip; Ko, Seung Hwan

2013-06-25

We introduce a facile approach to fabricate a metallic grid transparent conductor on a flexible substrate using selective laser sintering of metal nanoparticle ink. The metallic grid transparent conductors with high transmittance (>85%) and low sheet resistance (30 Ω/sq) are readily produced on glass and polymer substrates at large scale without any vacuum or high-temperature environment. Being a maskless direct writing method, the shape and the parameters of the grid can be easily changed by CAD data. The resultant metallic grid also showed a superior stability in terms of adhesion and bending. This transparent conductor is further applied to the touch screen panel, and it is confirmed that the final device operates firmly under continuous mechanical stress.

Dimensional accuracy of internal cooling channel made by selective laser melting (SLM And direct metal laser sintering (DMLS processes in fabrication of internally cooled cutting tools

Directory of Open Access Journals (Sweden)

Ghani S. A. C.

2017-01-01

Full Text Available Selective laser melting(SLM and direct metal laser sintering(DMLS are preferred additive manufacturing processes in producing complex physical products directly from CAD computer data, nowadays. The advancement of additive manufacturing promotes the design of internally cooled cutting tool for effectively used in removing generated heat in metal machining. Despite the utilisation of SLM and DMLS in a fabrication of internally cooled cutting tool, the level of accuracy of the parts produced remains uncertain. This paper aims at comparing the dimensional accuracy of SLM and DMLS in machining internally cooled cutting tool with a special focus on geometrical dimensions such as hole diameter. The surface roughness produced by the two processes are measured with contact perthometer. To achieve the objectives, geometrical dimensions of identical tool holders for internally cooled cutting tools fabricated by SLM and DMLS have been determined by using digital vernier calliper and various magnification of a portable microscope. In the current study, comparing internally cooled cutting tools made of SLM and DMLS showed that generally the higher degree of accuracy could be obtained with DMLS process. However, the observed differences in surface roughness between SLM and DMLS in this study were not significant. The most obvious finding to emerge from this study is that the additive manufacturing processes selected for fabricating the tool holders for internally cooled cutting tool in this research are capable of producing the desired internal channel shape of internally cooled cutting tool.

Superconductor-normal metal-superconductor process development for the fabrication of small Josephson junctions in ramp type configuration

International Nuclear Information System (INIS)

Poepel, R.; Hagedorn, D.; Weimann, T.; Buchholz, F.-I.; Niemeyer, J.

2000-01-01

At PTB, a fabrication process has been developed in SNS Nb/PdAu/Nb technology for the verification of small Josephson junctions (JJs) in the deep sub-micron range to enable the implementation of JJs as active elements in highly integrated superconducting circuits. Two steps of this technological development are described with regard to appropriately designed circuit layouts of JJ series arrays (JJAs), the first one in a conventional window type junction (WTJ) configuration and the second one in a ramp type junction (RTJ) configuration. Test circuits of JJAs containing up to 10 000 JJs have been fabricated and experimentally tested. In WTJ configuration, the circuits proved to be sensitive to external perturbing effects affecting the stability of circuit operation. In contrast to that, in RTJ configuration, the circuits realized showed correct function and a high grade of reliability of operation. To produce RTJ circuits, the technology parameters have been set to realize JJs with contact areas of A=0.25μmx1.3μm. At a thickness of the PdAu normal metal layer of d = 40 nm, the values achieved for the critical current density and for the product of critical current and normal state resistance are about j c = 200 k Acm -2 and about I c R N = 21 μV. (author)

Isolation plan for the southern end of the 313 Metal Fabrication Building

International Nuclear Information System (INIS)

Smith, D.S.

1997-02-01

The 313 Metal Fabrication Building was originally constructed as part of the Manhattan Project and underwent major remodeling and expansion in 1954. The building is divided into two sections that were separated by a fire wall. The first characterization of the 313(S) Building was conducted in 1995 to identify radiological, chemical, and other hazardous substances that may be encountered during the isolation activities. The intent of the isolation plan is to identify all known issues and reasonable solutions to these issues. Some issues will be solved during the building isolation activity, and other issues will remain unsolved until the actual demolition activity occurs

Production and use of metals and oxygen for lunar propulsion

Science.gov (United States)

Hepp, Aloysius F.; Linne, Diane L.; Groth, Mary F.; Landis, Geoffrey A.; Colvin, James E.

1991-01-01

Production, power, and propulsion technologies for using oxygen and metals derived from lunar resources are discussed. The production process is described, and several of the more developed processes are discussed. Power requirements for chemical, thermal, and electrical production methods are compared. The discussion includes potential impact of ongoing power technology programs on lunar production requirements. The performance potential of several possible metal fuels including aluminum, silicon, iron, and titanium are compared. Space propulsion technology in the area of metal/oxygen rocket engines is discussed.

Statistical methods to assess and control processes and products during nuclear fuel fabrication

International Nuclear Information System (INIS)

Weidinger, H.

1999-01-01

Very good statistical tools and techniques are available today to access the quality and the reliability of fabrication process as the original sources for a good and reliable quality of the fabricated processes. Quality control charts of different types play a key role and the high capability of modern electronic data acquisition technologies proved, at least potentially, a high efficiency in the more or less online application of these methods. These techniques focus mainly on stability and the reliability of the fabrication process. In addition, relatively simple statistical tolls are available to access the capability of fabrication process, assuming they are stable, to fulfill the product specifications. All these techniques can only result in as good a product as the product design is able to describe the product requirements necessary for good performance. Therefore it is essential that product design is strictly and closely performance oriented. However, performance orientation is only successful through an open and effective cooperation with the customer who uses or applies those products. During the last one to two decades in the west, a multi-vendor strategy has been developed by the utility, sometimes leading to three different fuel vendors for one reactor core. This development resulted in better economic conditions for the user but did not necessarily increase an open attitude with the vendor toward the using utility. The responsibility of the utility increased considerably to ensure an adequate quality of the fuel they received. As a matter of fact, sometimes the utilities had to pay a high price because of unexpected performance problems. Thus the utilities are now learning that they need to increase their knowledge and experience in the area of nuclear fuel quality management and technology. This process started some time ago in the west. However, it now also reaches the utilities in the eastern countries. (author)

Nonvolatile memory characteristics in metal-oxide-semiconductors containing metal nanoparticles fabricated by using a unique laser irradiation method

International Nuclear Information System (INIS)

Yang, JungYup; Yoon, KapSoo; Kim, JuHyung; Choi, WonJun; Do, YoungHo; Kim, ChaeOk; Hong, JinPyo

2006-01-01

Metal-oxide-semiconductor (MOS) capacitors with metal nanoparticles (Co NP) were successfully fabricated by utilizing an external laser exposure technique for application of non-volatile memories. Images of high-resolution transmission electron microscopy reveal that the spherically shaped Co NP are clearly embedded in the gate oxide layer. Capacitance-voltage measurements exhibit typical charging and discharging effects with a large flat-band shift. The effects of the tunnel oxide thickness and the different tunnel materials are analyzed using capacitance-voltage and retention characteristics. In addition, the memory characteristics of the NP embedded in a high-permittivity material are investigated because the thickness of conventionally available SiO 2 gates is approaching the quantum tunneling limit as devices are scaled down. Finally, the suitability of NP memory devices for nonvolatile memory applications is also discussed. The present results suggest that our unique laser exposure technique holds promise for the NP formation as floating gate elements in nonvolatile NP memories and that the quality of the tunnel oxide is very important for enhancing the retention properties of nonvolatile memory.

Aromatic plant production on metal contaminated soils

International Nuclear Information System (INIS)

Zheljazkov, Valtcho D.; Craker, Lyle E.; Xing Baoshan; Nielsen, Niels E.; Wilcox, Andrew

2008-01-01

Field and container experiments were conducted to assess the feasibility of growing aromatic crops in metal contaminated areas and the effect of metals on herbage and oil productivity. The field experiments were conducted in the vicinities of the Non-Ferrous Metals Combine (Zn-Cu smelter) near Plovdiv, Bulgaria using coriander, sage, dill, basil, hyssop, lemon balm, and chamomile grown at various distances from the smelter. Herbage essential oil yields of basil, chamomile, dill, and sage were reduced when they were grown closer to the smelter. Metal removal from the site with the harvestable plant parts was as high as 180 g ha -1 for Cd, 660 g ha -1 for Pb, 180 g ha -1 for Cu, 350 g ha -1 for Mn, and 205 g ha -1 for Zn. Sequential extraction of soil demonstrated that metal fractionation was affected by the distance to the smelter. With decreasing distance to the smelter, the transfer factor (TF) for Cu and Zn decreased but increased for Cd, while the bioavailability factor (BF) for Cd, Pb, Cu, Mn, and Zn decreased. Scanning electron microscopy and X-ray microanalyses of contaminated soil verified that most of the Pb, Cd, Mn, Cu, and Zn were in the form of small (< 1 μm) particles, although there were larger particles (1-5 μm) with high concentrations of individual metals. This study demonstrated that high concentrations of heavy metals in soil or growth medium did not result in metal transfer into the essential oil. Of the tested metals, only Cu at high concentrations may reduce oil content. Our results demonstrated that aromatic crops may not have significant phytoremediation potential, but growth of these crops in metal contaminated agricultural soils is a feasible alternative. Aromatic crops can provide economic return and metal-free final product, the essential oil

Aromatic plant production on metal contaminated soils

Energy Technology Data Exchange (ETDEWEB)

Zheljazkov, Valtcho D. [Mississippi State, Department of Plant and Soil Sciences and North Mississippi Research and Extension Center, 5421 Highway 145 South, Verona, MS 38879 (United States)], E-mail: vj40@pss.msstate.edu; Craker, Lyle E.; Xing Baoshan [Department of Plant and Soil Sciences, 12 Stockbridge Hall, University of Massachusetts, Amherst, MA 01003 (United States); Nielsen, Niels E. [Plant Nutrition and Soil Fertility Lab, Department of Agricultural Sciences, Royal Veterinary and Agricultural University, Thorvaldsensvej 40, DK1871, Copenhagen (Denmark); Wilcox, Andrew [Harper Adams University College, Newport, Shropshire, TF10 8NB (United Kingdom)

2008-06-01

Field and container experiments were conducted to assess the feasibility of growing aromatic crops in metal contaminated areas and the effect of metals on herbage and oil productivity. The field experiments were conducted in the vicinities of the Non-Ferrous Metals Combine (Zn-Cu smelter) near Plovdiv, Bulgaria using coriander, sage, dill, basil, hyssop, lemon balm, and chamomile grown at various distances from the smelter. Herbage essential oil yields of basil, chamomile, dill, and sage were reduced when they were grown closer to the smelter. Metal removal from the site with the harvestable plant parts was as high as 180 g ha{sup -1} for Cd, 660 g ha{sup -1} for Pb, 180 g ha{sup -1} for Cu, 350 g ha{sup -1} for Mn, and 205 g ha{sup -1} for Zn. Sequential extraction of soil demonstrated that metal fractionation was affected by the distance to the smelter. With decreasing distance to the smelter, the transfer factor (TF) for Cu and Zn decreased but increased for Cd, while the bioavailability factor (BF) for Cd, Pb, Cu, Mn, and Zn decreased. Scanning electron microscopy and X-ray microanalyses of contaminated soil verified that most of the Pb, Cd, Mn, Cu, and Zn were in the form of small (< 1 {mu}m) particles, although there were larger particles (1-5 {mu}m) with high concentrations of individual metals. This study demonstrated that high concentrations of heavy metals in soil or growth medium did not result in metal transfer into the essential oil. Of the tested metals, only Cu at high concentrations may reduce oil content. Our results demonstrated that aromatic crops may not have significant phytoremediation potential, but growth of these crops in metal contaminated agricultural soils is a feasible alternative. Aromatic crops can provide economic return and metal-free final product, the essential oil.

Effect of shock pressure on the structure and superconducting properties of Y-Ba-Cu-O in explosively fabricated bulk metal-matrix composites

Science.gov (United States)

Murr, L. E.; Niou, C. S.; Pradhan-Advani, M.

1991-01-01

While it is now well established that copper-oxide-based power, or virtually any other ceramic superconductor powder, can be consolidated and encapsulated within a metal matrix by explosive consolidation, the erratic superconductivity following fabrication has posed a major problem for bulk applications. The nature of this behavior was found to arise from microstructural damage created in the shock wave front, and the residual degradation in superconductivity was demonstrated to be directly related to the peak shock pressure. The explosively fabricated or shock loaded YBa2Cu3Ox examples exhibit drastically altered rho (or R) - T curves. The deterioration in superconductivity is even more noticeable in the measurement of ac magnetic susceptibility and flux exclusion or shielding fraction which is also reduced in proportion to increasing peak shock pressure. The high frequency surface resistance (in the GHz range) is also correspondingly compromised in explosively fabricated, bulk metal-matrix composites based on YBa2Cu3O7. Transmission electron microscopy (including lattice imaging techniques) is being applied in an effort to elucidate the fundamental (microstructural) nature of the shock-induced degradation of superconductivity and normal state conductivity. One focus of TEM observations has assumed that oxygen displaced from b-chains rather than oxygen-vacancy disorder in the basal plane of oxygen deficient YBa2Cu3Ox may be a prime mechanism. Shock-wave displaced oxygen may also be locked into new positions or interstitial clusters or chemically bound to displaced metal (possibly copper) atoms to form precipitates, or such displacements may cause the equivalent of local lattice cell changes as a result of stoichiometric changes. While the shock-induced suppression of T(sub c) is not desirable in the explosive fabrication of bulk metal-matrix superconductors, it may be turned into an advantage if the atomic-scale distortion can be understood and controlled as local

The industrial production of fuel elements; La fabrication en france des elements combustibles

Energy Technology Data Exchange (ETDEWEB)

Boussard, R [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires; Nadal, J [Societe Industrielle de Combustible Nucleaire (SICN), 75 - Paris (France); Pellen, A [Compagnie pour l' Etude et la Realisation de Combustibles Atomiques (CERCA), 75 - Paris (France)

1964-07-01

-pool type reactors. The authors show how the problem of the industrial production of rolled fuel elements has been solved in France, and give the three steps involved: 1 - Assembly of the plates made in the U.S.A., 2 - Rolling of the cores made in the U.S.A. to obtain the plates, 3 - Fabrication of the U-Al alloy and production of the cores. They then recall briefly the characteristics of the different fuel elements now in production. A description is given of the various stages of the production including information about the equipment; stress is laid on the extent of the controls carried out at each stage. In conclusion the authors consider the future development of this type of production taking into account the improvements planned and those which are possible. (authors) [French] Les auteurs traitent successivement de la fabrication industrielle des elements combustibles pour reacteurs de puissance de la filiere U naturel graphite-gaz et plus particulierement pour les centrales energetiques d'E.D.F. et de celle des elements combustibles a base d'U enrichi destines aux reacteurs experimentaux du type 'piscine'. 1ere Partie - LES ELEMENTS COMBUSTIBLES AVANCES POUR LES REACTEURS E.D.F.: Apres un bref rappel des caracteristiques des elements combustibles actuellement fabriques industriellement pour les reacteurs de MARCOULE et de CHINON, les auteurs indiquent les differentes etapes suivies pour aboutir au stade de la fabrication industrielle d'un element combustible nouveau, tant en ce qui concerne la gaine et eventuellement la chemise de graphite que le combustible lui-meme. Pour ce qui est de l'elaboration du combustible, ils decrivent les differentes operations en insistant sur les points originaux de la fabrication et de l'appareillage tels que: - coulees en moules chauds, - traitement thermique des alliages U.Mo 1 p. 100, - soudure des pastilles de fermeture des tubes, - gainage - controle aux differents stades. En ce qui concerne la fabrication des gaines, ils

Adaptive Robotic Fabrication for Conditions of Material Inconsistency

DEFF Research Database (Denmark)

Nicholas, Paul; Zwierzycki, Mateusz; Clausen Nørgaard, Esben

2017-01-01

This paper describes research that addresses the variable behaviour of industrial quality metals and the extension of computational techniques into the fabrication process. It describes the context of robotic incremental sheet metal forming, a freeform method for imparting 3D form onto a 2D thin...... and the fabrication process? Here, two adaptive methods are presented that aim to increase forming accuracy with only a minimum increase in fabrication time, and that maintain ongoing input from the results of the fabrication process. The first method is an online sensor-based strategy and the second method...

Energy and materials flows in the fabrication of iron and steel semifinished products

Energy Technology Data Exchange (ETDEWEB)

Darby, J.B. Jr.; Arons, R.M.

1979-08-01

The flow of energy and materials in the fabrication of iron and steel semifinished products from molten metal is discussed. The focus is on techniques to reduce the amount of energy required to produce the typical products of integrated steel plants and iron and steel foundries. In integrated steel plants, if only 50% of the steel being cast were continuously cast, industry-wide energy consumption would be reduced by 6 to 15%. Further major energy savings could be achieved by increased use of by-product gases and regenerators in the various reheat operations. Finally, systems optimization studies to maintain the even flow of materials at full capacity should yield further improvements in energy efficiency. In foundry operations, alternate heating methods in forging operations and the use of no-bake molding and core materials should result in substantial energy savings. Studies of specific operations will suggest housekeeping changes to minimize wasted energy. These changes might include fixing heat leaks, reducing floor space requirements, improving temperature regulation, lowering working temperatures in some steel-forming operations, redesigning products, and minimizing scrap generation. There is also a need for new, energy conserving technologies. A good example would be the development of nondestructive testing to determine the existence, location, and size of defects in ingots at elevated temperatures. A second example is the need to reduce, through system studies, the large amount of scrap typical of foundry operations. Finally, computer control of steel mill operations (materials flow, furnace residence times, excessive heating or overheating, and full capacity utilization of all facilities at all times) deserves further study.

Inert anode containing base metal and noble metal useful for the electrolytic production of aluminum

Science.gov (United States)

Ray, Siba P.; Liu, Xinghua

2000-01-01

An inert anode for production of metals such as aluminum is disclosed. The inert anode comprises a base metal selected from Cu and Ag, and at least one noble metal selected from Ag, Pd, Pt, Au, Rh, Ru, Ir and Os. The inert anode may optionally be formed of sintered particles having interior portions containing more base metal than noble metal and exterior portions containing more noble metal than base metal. In a preferred embodiment, the base metal comprises Cu, and the noble metal comprises Ag, Pd or a combination thereof.

In-process fault detection for textile fabric production: onloom imaging

Science.gov (United States)

Neumann, Florian; Holtermann, Timm; Schneider, Dorian; Kulczycki, Ashley; Gries, Thomas; Aach, Til

2011-05-01

Constant and traceable high fabric quality is of high importance both for technical and for high-quality conventional fabrics. Usually, quality inspection is carried out by trained personal, whose detection rate and maximum period of concentration are limited. Low resolution automated fabric inspection machines using texture analysis were developed. Since 2003, systems for the in-process inspection on weaving machines ("onloom") are commercially available. With these defects can be detected, but not measured quantitative precisely. Most systems are also prone to inevitable machine vibrations. Feedback loops for fault prevention are not established. Technology has evolved since 2003: Camera and computer prices dropped, resolutions were enhanced, recording speeds increased. These are the preconditions for real-time processing of high-resolution images. So far, these new technological achievements are not used in textile fabric production. For efficient use, a measurement system must be integrated into the weaving process; new algorithms for defect detection and measurement must be developed. The goal of the joint project is the development of a modern machine vision system for nondestructive onloom fabric inspection. The system consists of a vibration-resistant machine integration, a high-resolution machine vision system, and new, reliable, and robust algorithms with quality database for defect documentation. The system is meant to detect, measure, and classify at least 80 % of economically relevant defects. Concepts for feedback loops into the weaving process will be pointed out.

Two-photon polymerization of metal ions doped acrylate monomers and oligomers for three-dimensional structure fabrication

International Nuclear Information System (INIS)

Duan Xuanming; Sun Hongbo; Kaneko, Koshiro; Kawata, Satoshi

2004-01-01

We have investigated two-photon polymerization of metal ions doped acrylate monomers and oligomers which is applied for three-dimensional (3D) micro/nano-structure fabrication. Titanium (IV) ions doped urethane acrylate photopolymerizable resins were synthesized, and their optical and polymerization properties were investigated. The resolution of two-photon polymerization for micro/nanofabrication was evaluated. Titanium dioxide (TiO 2 ) nanoparticles were generated in the polymer matrix of micron-sized polymer structures. A 3D diamond photonic crystal structure, which consisted of polymer composite materials of TiO 2 nanoparticles, was successfully fabricated by direct laser writing and its photonic bandgap was confirmed. This work would give us a new solution for producing 3D micro/nanodevices of functional polymer composite materials

Lunar Metal Oxide Electrolysis with Oxygen and Photovoltaic Array Production Applications

Science.gov (United States)

Curreri, P. A.; Ethridge, E.; Hudson, S.; Sen, S.

2006-01-01

This paper presents the results of a Marshall Space Flight Center funded effort to conduct an experimental demonstration of the processing of simulated lunar resources by the molten oxide electrolysis (MOE) process to produce oxygen and metal from lunar resources to support human exploration of space. Oxygen extracted from lunar materials can be used for life support and propellant, and silicon and metallic elements produced can be used for in situ fabrication of thin-film solar cells for power production. The Moon is rich in mineral resources, but it is almost devoid of chemical reducing agents, therefore, molten oxide electrolysis, MOE, is chosen for extraction, since the electron is the most practical reducing agent. MOE was also chosen for following reasons. First, electrolytic processing offers uncommon versatility in its insensitivity to feedstock composition. Secondly, oxide melts boast the twin key attributes of highest solubilizing capacity for regolith and lowest volatility of any candidate electrolytes. The former is critical in ensuring high productivity since cell current is limited by reactant solubility, while the latter simplifies cell design by obviating the need for a gas-tight reactor to contain evaporation losses as would be the case with a gas or liquid phase fluoride reagent operating at such high temperatures. In the experiments reported here, melts containing iron oxide were electrolyzed in a low temperature supporting oxide electrolyte (developed by D. Sadoway, MIT). The production of oxygen and reduced iron were observed. Electrolysis was also performed on the supporting electrolyte with JSC-1 Lunar Simulant. The cell current for the supporting electrolyte alone is negligible while the current for the electrolyte with JSC-1 shows significant current and a peak at about -0.6 V indicating reductive reaction in the simulant.

Transparent Substrates for Plasmonic Sensing by Lithography-Free Fabrication

DEFF Research Database (Denmark)

Thilsted, Anil Haraksingh

This Ph.D. thesis presents fabrication and optimization of transparent plasmonic substrates that can be used for biological and chemical sensing by surface enhanced Raman spectroscopy (SERS) sensing and localized surface plasmon resonance refractive index (LSPR RI) sensing. These substrates are......-free fabrication methods, and resulted in large-area, high throughput and low cost production techniques. The fabrication techniques consisted of using aluminum patterned areas and reactive ion etching (RIE) to achieve nanopillars or nanocylinders in glass; using RIE to achieve nanopillars in silicon as a mould......, respectively. As the substrates were transparent, measurements from the backside were possible, showing a 44%, 1:7% and 71% Raman signal intensity in comparison to the measurements from the front, for the glass nanopillars, the polymer injected nanopillars and the transferred metal nanocaps, respectively...

Effect of Metals, Metalloids and Metallic Nanoparticles on Microalgae Growth and Industrial Product Biosynthesis: A Review.

Science.gov (United States)

Miazek, Krystian; Iwanek, Waldemar; Remacle, Claire; Richel, Aurore; Goffin, Dorothee

2015-10-09

Microalgae are a source of numerous compounds that can be used in many branches of industry. Synthesis of such compounds in microalgal cells can be amplified under stress conditions. Exposure to various metals can be one of methods applied to induce cell stress and synthesis of target products in microalgae cultures. In this review, the potential of producing diverse biocompounds (pigments, lipids, exopolymers, peptides, phytohormones, arsenoorganics, nanoparticles) from microalgae cultures upon exposure to various metals, is evaluated. Additionally, different methods to alter microalgae response towards metals and metal stress are described. Finally, possibilities to sustain high growth rates and productivity of microalgal cultures in the presence of metals are discussed.

40 CFR 415.110 - Applicability; description of the potassium metal production subcategory.

Science.gov (United States)

2010-07-01

... potassium metal production subcategory. 415.110 Section 415.110 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Potassium Metal Production Subcategory § 415.110 Applicability; description of the potassium metal production subcategory. The provisions of this subpart are applicable to discharges...

Nanorobotic end-effectors: Design, fabrication, and in situ characterization

Science.gov (United States)

Fan, Zheng

Nano-robotic end-effectors have promising applications for nano-fabrication, nano-manufacturing, nano-optics, nano-medical, and nano-sensing; however, low performances of the conventional end-effectors have prevented the widespread utilization of them in various fields. There are two major difficulties in developing the end-effectors: their nano-fabrication and their advanced characterization in the nanoscale. Here we introduce six types of end-effectors: the nanotube fountain pen (NFP), the super-fine nanoprobe, the metal-filled carbon nanotube (m CNT)-based sphere-on-pillar (SOP) nanoantennas, the tunneling nanosensor, and the nanowire-based memristor. The investigations on the NFP are focused on nano-fluidics and nano-fabrications. The NFP could direct write metallic "inks" and fabricating complex metal nanostructures from 0D to 3D with a position servo control, which is critically important to future large-scale, high-throughput nanodevice production. With the help of NFP, we could fabricate the end-effectors such as super-fine nanoprobe and m CNT-based SOP nanoantennas. Those end-effectors are able to detect local flaws or characterize the electrical/mechanical properties of the nanostructure. Moreover, using electron-energy-loss-spectroscopy (EELS) technique during the operation of the SOP optical antenna opens a new basis for the application of nano-robotic end-effectors. The technique allows advanced characterization of the physical changes, such as carrier diffusion, that are directly responsible for the device's properties. As the device was coupled with characterization techniques of scanning-trasmission-electron-microscopy (STEM), the development of tunneling nanosensor advances this field of science into quantum world. Furthermore, the combined STEM-EELS technique plays an important role in our understanding of the memristive switching performance in the nanowire-based memristor. The developments of those nano-robotic end-effectors expend the study

Distance-dependent metal enhanced fluorescence by flowerlike silver nanostructures fabricated in liquid crystalline phase

Science.gov (United States)

Zhang, Ying; Yang, Chengliang; Zhang, Guiyang; Peng, Zenghui; Yao, Lishuang; Wang, Qidong; Cao, Zhaoliang; Mu, Quanquan; Xuan, Li

2017-10-01

Flowerlike silver nanostructure substrates were fabricated in liquid crystalline phase and the distance dependent property of metal enhanced fluorescence for such substrate was studied for the first time. The distance between silver nanostructures and fluorophore was controlled by the well-established layer-by-layer (LbL) technique constructing alternate layers of poly (allylamine hydrochloride) (PAH) and poly (sodium 4-styrenesulfonate) (PSS). The Rhodamine 6G (R6G) molecules were electrostatically attached to the outmost negative charged PSS layer. The fluorescence enhancement factor of flowerlike nanostructure substrate increased firstly and then decreased with the distance increasing. The best enhanced fluorescence intensity of 71 fold was obtained at a distance of 5.2 nm from the surface of flowerlike silver nanostructure. The distance for best enhancement effect is an instructive parameter for the applications of such substrates and could be used in the practical MEF applications with the flowerlike nanostructure substrates fabricated in such way which is simple, controllable and cost-effective.

Manufacturing processes in the textile industry. Expert Systems for fabrics production

Directory of Open Access Journals (Sweden)

Juan BULLON

2017-03-01

Full Text Available The textile industry is characterized by the economic activity whose objective is the production of fibres, yarns, fabrics, clothing and textile goods for home and decoration,as well as technical and industrial purposes. Within manufacturing, the Textile is one of the oldest and most complex sectors which includes a large number of sub-sectors covering the entire production cycle, from raw materials and intermediate products, to the production of final products. Textile industry activities present different subdivisions, each with its own traits. The length of the textile process and the variety of its technical processes lead to the coexistence of different sub-sectors in regards to their business structure and integration. The textile industry is developing expert systems applications to increase production, improve quality and reduce costs. The analysis of textile designs or structures includes the use of mathematical models to simulate the behavior of the textile structures (yarns, fabrics and knitting. The Finite Element Method (FEM has largely facilitated the prediction of the behavior of that textile structure under mechanical loads. For classification problems Artificial Neural Networks (ANNs haveproved to be a very effective tool as a quick and accurate solution. The Case-Based Reasoning (CBR method proposed in this study complements the results of the finite element simulation, mathematical modeling and neural networks methods.

Silver Nanowire Arrays : Fabrication and Applications

OpenAIRE

Feng, Yuyi

2016-01-01

Nanowire arrays have increasingly received attention for their use in a variety of applications such as surface-enhanced Raman scattering (SERS), plasmonic sensing, and electrodes for photoelectric devices. However, until now, large scale fabrication of device-suitable metallic nanowire arrays on supporting substrates has seen very limited success. This thesis describes my work rst on the development of a novel successful processing route for the fabrication of uniform noble metallic (e.g. A...

V-groove plasmonic waveguides fabricated by nanoimprint lithography

DEFF Research Database (Denmark)

Fernandez-Cuesta, I.; Nielsen, R.B.; Boltasseva, Alexandra

2007-01-01

Propagation of channel plasmon-polariton modes in the bottom of a metal V groove has been recently demonstrated. It provides a unique way of manipulating light at nanometer length scale. In this work, we present a method based on nanoimprint lithography that allows parallel fabrication of integra...... of integrated optical devices composed of metal V grooves. This method represents an improvement with respect to previous works, where the V grooves were fabricated by direct milling of the metal, in terms of robustness and throughput. © 2007 American Vacuum Society......Propagation of channel plasmon-polariton modes in the bottom of a metal V groove has been recently demonstrated. It provides a unique way of manipulating light at nanometer length scale. In this work, we present a method based on nanoimprint lithography that allows parallel fabrication...

Clinical marginal and internal fit of metal ceramic crowns fabricated with a selective laser melting technology.

Science.gov (United States)

Huang, Zhuoli; Zhang, Lu; Zhu, Jingwei; Zhang, Xiuyin

2015-06-01

Selective laser melting (SLM) technology has been introduced to fabricate dental restorations. However, the fit of these restorations still needs further study. The purpose of this in vivo investigation was to compare the marginal and internal fit of SLM metal ceramic crowns with 2 lost-wax cast metal ceramic crowns and to evaluate the influence of tooth type on the marginal and internal fit of these crowns. A total of 330 metal ceramic crowns were evaluated. The metal copings were fabricated with SLM Co-Cr, cast Au-Pt, and cast Co-Cr alloy (n=110). The marginal and internal gaps of crowns were recorded by using a replica technique. The anterior and premolar replicas were sectioned 2 times, and molar replicas were sectioned 4 times. The marginal and internal gap width of each cross section was examined by stereomicroscope at ×30 magnification. Two-way analysis of variance was performed to identify the statistical difference among the groups. The marginal fit of the SLM Co-Cr group (75.6 ±32.6 μm) was not different from the cast Au-Pt group (76.8 ±32.1 μm) (P>.05) but was better than the cast Co-Cr group (91.0 ±36.3 μm) (P.05). The mean occlusal gap width of the SLM Co-Cr group (309.8 ±106.6 μm) was significantly higher than that of the cast Au-Pt group (254.6 ±109.6 μm) and the cast Co-Cr group (249.6 ±110.4 μm) (P.05). Also, no significant difference was found in the axial fit among the anterior group (138.3 ±52.5 μm), the premolar group (132.9 ±50.4 μm), and the molar group (134.4 ±52.5 μm) (P>.05). The anterior group (267.6 ±110.2 μm) did not differ from the premolar group (270.2 ±112.8 μm) and the molar group (268.6 ±110.5 μm) in occlusal fit (P>.05). The marginal fit of SLM Co-Cr metal ceramic crowns was similar to that of the cast Au-Pt metal ceramic crowns and was better than that of the cast Co-Cr metal ceramic crowns. The SLM Co-Cr metal ceramic crowns were not significantly different from the 2 cast metal ceramic crowns in axial

Effect of Metals, Metalloids and Metallic Nanoparticles on Microalgae Growth and Industrial Product Biosynthesis: A Review

Science.gov (United States)

Miazek, Krystian; Iwanek, Waldemar; Remacle, Claire; Richel, Aurore; Goffin, Dorothee

2015-01-01

Microalgae are a source of numerous compounds that can be used in many branches of industry. Synthesis of such compounds in microalgal cells can be amplified under stress conditions. Exposure to various metals can be one of methods applied to induce cell stress and synthesis of target products in microalgae cultures. In this review, the potential of producing diverse biocompounds (pigments, lipids, exopolymers, peptides, phytohormones, arsenoorganics, nanoparticles) from microalgae cultures upon exposure to various metals, is evaluated. Additionally, different methods to alter microalgae response towards metals and metal stress are described. Finally, possibilities to sustain high growth rates and productivity of microalgal cultures in the presence of metals are discussed. PMID:26473834

Effect of Metals, Metalloids and Metallic Nanoparticles on Microalgae Growth and Industrial Product Biosynthesis: A Review

Directory of Open Access Journals (Sweden)

Krystian Miazek

2015-10-01

Full Text Available Microalgae are a source of numerous compounds that can be used in many branches of industry. Synthesis of such compounds in microalgal cells can be amplified under stress conditions. Exposure to various metals can be one of methods applied to induce cell stress and synthesis of target products in microalgae cultures. In this review, the potential of producing diverse biocompounds (pigments, lipids, exopolymers, peptides, phytohormones, arsenoorganics, nanoparticles from microalgae cultures upon exposure to various metals, is evaluated. Additionally, different methods to alter microalgae response towards metals and metal stress are described. Finally, possibilities to sustain high growth rates and productivity of microalgal cultures in the presence of metals are discussed.

Freeform Fabrication of Magnetophotonic Crystals with Diamond Lattices of Oxide and Metallic Glasses for Terahertz Wave Control by Micro Patterning Stereolithography and Low Temperature Sintering

Directory of Open Access Journals (Sweden)

Maasa Nakano

2013-04-01

Full Text Available Micrometer order magnetophotonic crystals with periodic arranged metallic glass and oxide glass composite materials were fabricated by stereolithographic method to reflect electromagnetic waves in terahertz frequency ranges through Bragg diffraction. In the fabrication process, the photo sensitive acrylic resin paste mixed with micrometer sized metallic glass of Fe72B14.4Si9.6Nb4 and oxide glass of B2O3·Bi2O3 particles was spread on a metal substrate, and cross sectional images of ultra violet ray were exposed. Through the layer by layer stacking, micro lattice structures with a diamond type periodic arrangement were successfully formed. The composite structures could be obtained through the dewaxing and sintering process with the lower temperature under the transition point of metallic glass. Transmission spectra of the terahertz waves through the magnetophotonic crystals were measured by using a terahertz time domain spectroscopy.

Product Conversion: The Link between Separations and Fuel Fabrication

International Nuclear Information System (INIS)

Felker, L.K.; Vedder, R.J.; Walker, E.A.; Collins, E.D.

2008-01-01

Several chemical processing flowsheets are under development for the separation and isolation of the actinide, lanthanide, and fission product streams in spent nuclear fuel. The conversion of these product streams to solid forms, typically oxides, is desired for waste disposition and recycle of product fractions back into transmutation fuels or targets. The modified direct denitration (MDD) process developed at Oak Ridge National Laboratory (ORNL) in the 1980's offers significant advantages for the conversion of the spent fuel products to powder form suitable for direct fabrication into recycle fuels. A glove-box-contained MDD system and a fume-hood-contained system have been assembled at ORNL for the purposes of testing the co-conversion of uranium and mixed-actinide products. The current activities are focused on the conversion of the first products from the processing of spent nuclear fuel in the Coupled End-to-End Demonstration currently being conducted at ORNL. (authors)

Determination of Toxic Metals in Indian Smokeless Tobacco Products

Directory of Open Access Journals (Sweden)

Dhanashri Dhaware

2009-01-01

Full Text Available This study targets the lesser-known ingredients of smokeless tobacco products, i.e., the toxic metals, in Indian brands. The metals selected in the study included lead (Pb, cadmium (Cd, arsenic (As, copper (Cu, mercury (Hg, and selenium (Se. The differential pulse anodic stripping voltammetry (DPASV technique was used for estimating the metals Pb, Cd, and Cu; square wave voltammetry for As; and the cold vapor atomic absorption technique for Hg. The resulting levels of the metals were compared to the daily consumption of the smokeless tobacco products. It was observed that almost 30% of gutkha brand samples exceeded the permissible levels of metals Pb and Cu, when compared to the provisional tolerable intake limits determined by the FAO/WHO. The reliability of data was assured by analyzing standard reference materials.

Nanowire-decorated microscale metallic electrodes

DEFF Research Database (Denmark)

Vlad, A.; Mátéfi-Tempfli, M.; Antohe, V.A.

2008-01-01

The fabrication of metallic nanowire patterns within anodic alumina oxide (AAO) membranes on top of continuous conducting substrates are discussed. The fabrication protocol is based on the realization of nanowire patterns using supported nanoporous alumina templates (SNAT) prepared on top...... of lithographically defined metallic microelectrodes. The anodization of the aluminum permits electroplating only on top of the metallic electrodes, leading to the nanowire patterns having the same shape as the underlying metallic tracks. The variation in the fabricated structures between the patterned and non......-patterned substrates can be interpreted in terms of different behavior during anodization. The improved quality of fabricated nanowire patterns is clearly demonstrated by the SEM imaging and the uniform growth of nanowires inside the alumina template is observed without any significant height variation....

Role of modern analytical techniques in the production of uranium metal

International Nuclear Information System (INIS)

Hareendran, K.N.; Roy, S.B.

2009-01-01

Production of nuclear grade uranium metal conforming to its stringent specification with respect to metallic and non metallic impurities necessitates implementation of a comprehensive quality control regime. Founding members of Uranium Metal Plant realised the importance of this aspect of metal production and a quality control laboratory was set up as part of the production plant. In the initial stages of its existence, the laboratory mainly catered to the process control analysis of the plant process samples and Spectroscopy Division and Analytical Division of BARC provided analysis of trace metallic impurities in the intermediates as well as in the product uranium metal. This laboratory also provided invaluable R and D support for the optimization of the process involving both calciothermy and magnesiothermy. Prior to 1985, analytical procedures used were limited to classical methods of analysis with minimal instrumental procedures. The first major analytical instrument, a Flame AAS was installed in 1985 and a beginning to the trace analysis was made. However during the last 15 years the Quality Control Section has modernized the analytical set up by acquiring appropriate instruments. Presently the facility has implemented a complete quality control and quality assurance program required to cover all aspects of uranium metal production viz analysis of raw materials, process samples, waste disposal samples and also determination of all the specification elements in uranium metal. The current analytical practices followed in QCS are presented here

A novel coping metal material CoCrCu alloy fabricated by selective laser melting with antimicrobial and antibiofilm properties

Energy Technology Data Exchange (ETDEWEB)

Ren, Ling [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Memarzadeh, Kaveh [Institute of Dentistry, Barts and The London School of Medicine & Dentistry, Queen Mary University of London, Newark Street, London E1 2AT (United Kingdom); Zhang, Shuyuan; Sun, Ziqing; Yang, Chunguang [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Ren, Guogang [University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); Allaker, Robert P., E-mail: r.p.allaker@qmul.ac.uk [Institute of Dentistry, Barts and The London School of Medicine & Dentistry, Queen Mary University of London, Newark Street, London E1 2AT (United Kingdom); Yang, Ke, E-mail: kyang@imr.ac.cn [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China)

2016-10-01

Objective: The aim of this study was to fabricate a novel coping metal CoCrCu alloy using a selective laser melting (SLM) technique with antimicrobial and antibiofilm activities and to investigate its microstructure, mechanical properties, corrosion resistance and biocompatibility. Methods: Novel CoCrCu alloy was fabricated using SLM from a mixture of commercial CoCr based alloy and elemental Cu powders. SLM CoCr without Cu served as control. Antibacterial activity was analyzed using standard antimicrobial tests, and antibiofilm properties were investigated using confocal laser scanning microscope. Cu distribution and microstructure were determined using scanning electron microscope, optical microscopy and X-ray diffraction. Corrosion resistance was evaluated by potential dynamic polarization and biocompatibility measured using an MTT assay. Results: SLM CoCrCu alloys were found to be bactericidal and able to inhibit biofilm formation. Other factors such as microstructure, mechanical properties, corrosion resistance and biocompatibility were similar to those of SLM CoCr alloys. Significance: The addition of appropriate amounts of Cu not only maintains normal beneficial properties of CoCr based alloys, but also provides SLM CoCrCu alloys with excellent antibacterial and antibiofilm capabilities. This material has the potential to be used as a coping metal for dental applications. - Highlights: • Novel CoCrCu alloys were fabricated by using selective laser melting (SLM). • SLM CoCrCu alloys showed satisfied antimicrobial and antibiofilm activities. • SLM CoCrCu alloys have no cytotoxic effect on normal cells. • Other properties of SLM CoCrCu alloys were similar to SLM CoCr alloys. • SLM CoCrCu alloys have the potential to be used as coping metals.

Fabrication and characterization of NiO based metal−insulator−metal diode using Langmuir-Blodgett method for high frequency rectification

Directory of Open Access Journals (Sweden)

Ibrahim Azad

2018-04-01

Full Text Available Thin film metal–insulator–metal (MIM diodes have attracted significant attention for use in infrared energy harvesting and detection applications. As demonstrated over the past decades, MIM or metal-insulator-insulator-metal (MIIM diodes can operate at the THz frequencies range by quantum tunneling of electrons. The aim of this work is to synthesize required ultra-thin insulating layers and fabricate MIM diodes using the Langmuir-Blodgett (LB technique. The nickel stearate (NiSt LB precursor film was deposited on glass, silicon (Si, ITO glass and gold coated silicon substrates. The photodesorption (UV exposure and the thermodesorption (annealing at 100 °C and 350 °C methods were used to remove organic components from the NiSt LB film and to achieve a uniform homogenous nickel oxide (NiO film. These ultrathin NiO films were characterized by EDS, AFM, FTIR and cyclic voltammetry methods, respectively. The MIM diode was fabricated by depositing nickel (Ni on the NiO film, all on a gold (Au plated silicon (Si substrate. The current (I-voltage (V characteristics of the fabricated diode were studied to understand the conduction mechanism assumed to be tunneling of electron through the ultra-thin insulating layer. The sensitivity of the diode was measured to be as high as 35 V-1. The diode resistance was ∼100 ohms (at a bias voltage of 0.60 V, and the rectification ratio was about 22 (for a signal voltage of ±200 mV. At the bias point, the diode response demonstrated significant non-linearity and high asymmetry, which are very desirable characteristics for applications in infrared detection and harvesting.

A novel coping metal material CoCrCu alloy fabricated by selective laser melting with antimicrobial and antibiofilm properties

International Nuclear Information System (INIS)

Ren, Ling; Memarzadeh, Kaveh; Zhang, Shuyuan; Sun, Ziqing; Yang, Chunguang; Ren, Guogang; Allaker, Robert P.; Yang, Ke

2016-01-01

Objective: The aim of this study was to fabricate a novel coping metal CoCrCu alloy using a selective laser melting (SLM) technique with antimicrobial and antibiofilm activities and to investigate its microstructure, mechanical properties, corrosion resistance and biocompatibility. Methods: Novel CoCrCu alloy was fabricated using SLM from a mixture of commercial CoCr based alloy and elemental Cu powders. SLM CoCr without Cu served as control. Antibacterial activity was analyzed using standard antimicrobial tests, and antibiofilm properties were investigated using confocal laser scanning microscope. Cu distribution and microstructure were determined using scanning electron microscope, optical microscopy and X-ray diffraction. Corrosion resistance was evaluated by potential dynamic polarization and biocompatibility measured using an MTT assay. Results: SLM CoCrCu alloys were found to be bactericidal and able to inhibit biofilm formation. Other factors such as microstructure, mechanical properties, corrosion resistance and biocompatibility were similar to those of SLM CoCr alloys. Significance: The addition of appropriate amounts of Cu not only maintains normal beneficial properties of CoCr based alloys, but also provides SLM CoCrCu alloys with excellent antibacterial and antibiofilm capabilities. This material has the potential to be used as a coping metal for dental applications. - Highlights: • Novel CoCrCu alloys were fabricated by using selective laser melting (SLM). • SLM CoCrCu alloys showed satisfied antimicrobial and antibiofilm activities. • SLM CoCrCu alloys have no cytotoxic effect on normal cells. • Other properties of SLM CoCrCu alloys were similar to SLM CoCr alloys. • SLM CoCrCu alloys have the potential to be used as coping metals.

Directed light fabrication of rhenium components

Energy Technology Data Exchange (ETDEWEB)

Milewski, J.O.; Thoma, D.J.; Lewis, G.K.

1997-02-01

Directed Light Fabrication (DLF) is a direct metal deposition process that fuses powder, delivered by gas into the focal zone of a high powered laser beam to form fully dense near-net shaped components. This is accomplished in one step without the use of molds, dies, forming, pressing, sintering or forging equipment. DLF is performed in a high purity inert environment free from the contaminants associated with conventional processing such as oxide and carbon pickup, lubricants, binding agents, cooling or cleaning agents. Applications using rhenium have historically been limited in part by its workability and cost. This study demonstrates the ability to fuse rhenium metal powder, using a DLF machine, into free standing rods and describes the associated parameter study. Microstructural comparisons between DLF deposited rhenium and commercial rhenium sheet product is performed. This research combined with existing DLF technology demonstrates the feasibility of forming complex rhenium, metal shapes directly from powder.

antimicrobial properties of some natural and synthetic fabrics modified by radiation treatments

International Nuclear Information System (INIS)

Mohamed, R.M.A.

2008-01-01

natural and synthetic fabrics have been treated with different antimicrobial metal complexes under the effect of gamma radiation . in this regard, cotton, cotton/PET blend and PET were grafted with acrylic acid by gamma radiation and this grafted fabrics were complexed with Cu(ll),Ni(ll)and Co(ll) metal ions . the antimicrobial properties were evaluated by the measurement of tensile strength of fabrics after burring in a soil for one and two weeks as well as the effect of this treatment on the growth of certain bacteria and fungi incubated on a culture for 48 hours. the results showed that the highest protection to cotton, cotton/PET blend and PET fabrics by using Cu(ll) ion in the complexation process, where the order of protection by metals is Cu(ll) > Co(ll)> Ni(ll), moreover, the more grafted fabrics the more complexed fabrics with metal ions and is higher protection against microorganisms . the treatment with the metal ions has nearly no effect on the chemical and physical properties of the natural or the synthetic fabrics as indicated from the analysis by TGA, sem, ion exchange testing and wettability testing.

Adaptive Robotic Fabrication for Conditions of Material Inconsistency

DEFF Research Database (Denmark)

Nicholas, Paul; Zwierzycki, Mateusz; Clausen Nørgaard, Esben

2017-01-01

This paper describes research that addresses the variable behaviour of industrial quality metals and the extension of computational techniques into the fabrication process. It describes the context of robotic incremental sheet metal forming, a freeform method for imparting 3D form onto a 2D thin ...... is an offline predictive strategy based on machine learning. Rigidisation of thin metal skins......This paper describes research that addresses the variable behaviour of industrial quality metals and the extension of computational techniques into the fabrication process. It describes the context of robotic incremental sheet metal forming, a freeform method for imparting 3D form onto a 2D thin...

Development of Metallic Fuels for Actinide Transmutation

Energy Technology Data Exchange (ETDEWEB)

Hayes, Steven Lowe [Idaho National Laboratory; Fielding, Randall Sidney [Idaho National Laboratory; Benson, Michael Timothy [Idaho National Laboratory; Chichester, Heather Jean MacLean [Idaho National Laboratory; Carmack, William Jonathan [Idaho National Laboratory

2015-09-01

Research and development activities on metallic fuels are focused on their potential use for actinide transmutation in future sodium fast reactors. As part of this application, there is also a need for a near zero-loss fabrication process and a desire to demonstrate a multifold increase in burnup potential. The incorporation of Am and Np into the traditional U-20Pu-10Zr metallic fuel alloy was demonstrated in the US during the Integral Fast Reactor Program of the 1980’s and early 1990’s. However, the conventional counter gravity injection casting method performed under vacuum, previously used to fabricate these metallic fuel alloys, was not optimized for mitigating loss of the volatile Am constituent in the casting charge; as a result, approximately 40% of the Am casting charge failed to be incorporated into the as-cast fuel alloys. Fabrication development efforts of the past few years have pursued an optimized bottom-pour casting method to increase utilization of the melted charge to near 100%, and a differential pressure casting approach, performed under an argon overpressure, has been demonstrated to result in essentially no loss of Am due to volatilization during fabrication. In short, a path toward zero-loss fabrication of metallic fuels including minor actinides has been shown to be feasible. Irradiation testing of advanced metallic fuel alloys in the Advanced Test Reactor (ATR) has been underway since 2003. Testing in the ATR is performed inside of cadmium-shrouded positions to remove >99% of the thermal flux incident on the test fuels, resulting in an epi-thermal driven fuel test that is free from gross flux depression and producing an essentially prototypic radial temperature profile inside the fuel rodlets. To date, three irradiation test series (AFC-1,2,3) have been completed. Over 20 different metallic fuel alloys have been tested to burnups as high as 30% with constituent compositions of Pu up to 30%, Am up to 12%, Np up to 10%, and Zr between 10

LIFE CYCLE INVENTORY ANALYSIS IN THE PRODUCTION OF METALS USED IN PHOTOVOLTAICS.

Energy Technology Data Exchange (ETDEWEB)

FTHENAKIS,V.M.; KIM, H.C.; WANG, W.

2007-03-30

Material flows and emissions in all the stages of production of zinc, copper, aluminum, cadmium, indium, germanium, gallium, selenium, tellurium, and molybdenum were investigated. These metals are used selectively in the manufacture of solar cells, and emission and energy factors in their production are used in the Life Cycle Analysis (LCA) of photovoltaics. Significant changes have occurred in the production and associated emissions for these metals over the last 10 years, which are not described in the LCA databases. Furthermore, emission and energy factors for several of the by-products of the base metal production were lacking. This report aims in updating the life-cycle inventories associated with the production of the base metals (Zn, Cu, Al, Mo) and in defining the emission and energy allocations for the minor metals (Cd, In, Ge, Se, Te and Ga) used in photovoltaics.

Design, fabrication, and application of a directional thermal processing system for controlled devitrification of metallic glasses

Science.gov (United States)

Meyer, Megan Anne Lamb

The potential of using metallic glass as a pathway to obtaining novel morphologies and metastable phases has been garnering attention since their discovery. Several rapid solidification techniques; such as gas atomization, melt spinning, laser melting, and splat quenching produce amorphous alloys. A directional thermal processing system (DTPS) was designed, fabricated and characterized for the use of zone processing or gradient-zone processing of materials. Melt-spun CuZr metallic glass alloy was subjected to the DTPS and the relaxation and crystallization responses of the metallic glass were characterized. A range of processing parameters were developed and analyzed that would allow for devitrification to occur. The relaxation and crystallization responses were compared with traditional heat treatment methods of metallic glasses. The new processing method accessed equilibrium and non-equilibrium phases of the alloy and the structures were found to be controllable and sensitive to processing conditions. Crystallized fraction, crystallization onset temperature, and structural relaxation were controlled through adjusting the processing conditions, such as the hot zone temperature and sample velocity. Reaction rates computed from isothermal (TTT) transformation data were not found to be reliable, suggesting that the reaction kinetics are not additive. This new processing method allows for future studying of the thermal history effects of metallic glasses.

An automated flow injection system for metal determination by flame atomic absorption spectrometry involving on-line fabric disk sorptive extraction technique.

Science.gov (United States)

Anthemidis, A; Kazantzi, V; Samanidou, V; Kabir, A; Furton, K G

2016-08-15

A novel flow injection-fabric disk sorptive extraction (FI-FDSE) system was developed for automated determination of trace metals. The platform was based on a minicolumn packed with sol-gel coated fabric media in the form of disks, incorporated into an on-line solid-phase extraction system, coupled with flame atomic absorption spectrometry (FAAS). This configuration provides minor backpressure, resulting in high loading flow rates and shorter analytical cycles. The potentials of this technique were demonstrated for trace lead and cadmium determination in environmental water samples. The applicability of different sol-gel coated FPSE media was investigated. The on-line formed complex of metal with ammonium pyrrolidine dithiocarbamate (APDC) was retained onto the fabric surface and methyl isobutyl ketone (MIBK) was used to elute the analytes prior to atomization. For 90s preconcentration time, enrichment factors of 140 and 38 and detection limits (3σ) of 1.8 and 0.4μgL(-1) were achieved for lead and cadmium determination, respectively, with a sampling frequency of 30h(-1). The accuracy of the proposed method was estimated by analyzing standard reference materials and spiked water samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Direct fabrication of metal-free hollow graphene balls with a self-supporting structure as efficient cathode catalysts of fuel cell

Energy Technology Data Exchange (ETDEWEB)

Lu, Yanqi; Liu, Mingda; Nie, Huagui, E-mail: huaguinie@126.com; Gu, Cancan; Liu, Ming; Yang, Zhi, E-mail: yang201079@126.com; Yang, Keqin; Chen, Xi’an; Huang, Shaoming, E-mail: smhuang@wzu.edu.cn [Wenzhou University, Nanomaterials and Chemistry Key Laboratory (China)

2016-06-15

Despite the good progress in developing carbon catalysts for oxygen reduction reaction (ORR), the current metal-free carbon catalysts are still far from satisfactory for large-scale applications of fuel cell. Developing hollow graphene balls with a self-supporting structure is considered to be an ideal method to inhibit graphene stacking and improve their catalytic performance. Herein, we fabricated metal-free hollow graphene balls with a self-supporting structure, through using a new strategy that involves direct metal-free catalytic growth from assembly of SiO{sub 2} spheres. To our knowledge, although much researches involving the synthesis of graphene balls have been reported, investigations into the direct metal-free catalytic growth of hollow graphene balls are rare. Furthermore, the electrocatalytic performance shows that the resulting hollow graphene balls have significantly high catalytic activity. More importantly, such catalysts also possess much improved stability and better methanol tolerance in alkaline media during the ORR compared with commercial Pt/C catalysts. The outstanding performances coupled with an easy and inexpensive preparing method indicated the great potential of the hollow graphene balls with a self-supporting structure in large-scale applications of fuel cell.Graphical AbstractHollow graphene balls with a self-supporting structure have been successfully fabricated, through using a new strategy that involves direct metal-free catalytic growth from 3D assembly of SiO{sub 2} spheres. The hollow graphene balls can exhibit a high catalytic activity, long-term stability, and an excellent methanol tolerance for the oxygen reduction reaction.

Direct fabrication of metal-free hollow graphene balls with a self-supporting structure as efficient cathode catalysts of fuel cell

International Nuclear Information System (INIS)

Lu, Yanqi; Liu, Mingda; Nie, Huagui; Gu, Cancan; Liu, Ming; Yang, Zhi; Yang, Keqin; Chen, Xi’an; Huang, Shaoming

2016-01-01

Despite the good progress in developing carbon catalysts for oxygen reduction reaction (ORR), the current metal-free carbon catalysts are still far from satisfactory for large-scale applications of fuel cell. Developing hollow graphene balls with a self-supporting structure is considered to be an ideal method to inhibit graphene stacking and improve their catalytic performance. Herein, we fabricated metal-free hollow graphene balls with a self-supporting structure, through using a new strategy that involves direct metal-free catalytic growth from assembly of SiO_2 spheres. To our knowledge, although much researches involving the synthesis of graphene balls have been reported, investigations into the direct metal-free catalytic growth of hollow graphene balls are rare. Furthermore, the electrocatalytic performance shows that the resulting hollow graphene balls have significantly high catalytic activity. More importantly, such catalysts also possess much improved stability and better methanol tolerance in alkaline media during the ORR compared with commercial Pt/C catalysts. The outstanding performances coupled with an easy and inexpensive preparing method indicated the great potential of the hollow graphene balls with a self-supporting structure in large-scale applications of fuel cell.Graphical AbstractHollow graphene balls with a self-supporting structure have been successfully fabricated, through using a new strategy that involves direct metal-free catalytic growth from 3D assembly of SiO_2 spheres. The hollow graphene balls can exhibit a high catalytic activity, long-term stability, and an excellent methanol tolerance for the oxygen reduction reaction

State-of-art of modern technologies for metals production

Energy Technology Data Exchange (ETDEWEB)

Holappa, L [Helsinki Univ. of Technology, Otaniemi (Finland). Lab. of Metallurgy

1996-12-31

The future raw materials are becoming lower in metal content and more complex, multimetal concentrates will be utilized. This will give challenges for metallurgists to develop new, efficient and energy saving processes. The main impacts for current and future production technologies come from energy need and environmental issues of the production processes themselves as well as the inevitable energy production for the metal making. Metals production consumes huge amount of energy, roughly 10 pct of the global energy consumption is caused by metallurgists. That is the necessity but it also means energy saving is one of the metallurgical industry have been enormous when looking back to the history. Since the 1960`s the efforts of the industry together with the strict legislation in the industrialized countries have conducted to greatly decreased emissions and improved pollution control. Breakthrough of new processes like copper flash smelting has aided this positive progress

State-of-art of modern technologies for metals production

Energy Technology Data Exchange (ETDEWEB)

Holappa, L. [Helsinki Univ. of Technology, Otaniemi (Finland). Lab. of Metallurgy

1995-12-31

The future raw materials are becoming lower in metal content and more complex, multimetal concentrates will be utilized. This will give challenges for metallurgists to develop new, efficient and energy saving processes. The main impacts for current and future production technologies come from energy need and environmental issues of the production processes themselves as well as the inevitable energy production for the metal making. Metals production consumes huge amount of energy, roughly 10 pct of the global energy consumption is caused by metallurgists. That is the necessity but it also means energy saving is one of the metallurgical industry have been enormous when looking back to the history. Since the 1960`s the efforts of the industry together with the strict legislation in the industrialized countries have conducted to greatly decreased emissions and improved pollution control. Breakthrough of new processes like copper flash smelting has aided this positive progress

Automobile sheet metal part production with incremental sheet forming

Directory of Open Access Journals (Sweden)

İsmail DURGUN

2016-02-01

Full Text Available Nowadays, effect of global warming is increasing drastically so it leads to increased interest on energy efficiency and sustainable production methods. As a result of adverse conditions, national and international project platforms, OEMs (Original Equipment Manufacturers, SMEs (Small and Mid-size Manufacturers perform many studies or improve existing methodologies in scope of advanced manufacturing techniques. In this study, advanced manufacturing and sustainable production method "Incremental Sheet Metal Forming (ISF" was used for sheet metal forming process. A vehicle fender was manufactured with or without die by using different toolpath strategies and die sets. At the end of the study, Results have been investigated under the influence of method and parameters used.Keywords: Template incremental sheet metal, Metal forming

Crack and wear behavior of SiC particulate reinforced aluminium based metal matrix composite fabricated by direct metal laser sintering process

International Nuclear Information System (INIS)

Ghosh, Subrata Kumar; Saha, Partha

2011-01-01

In this investigation, crack density and wear performance of SiC particulate (SiCp) reinforced Al-based metal matrix composite (Al-MMC) fabricated by direct metal laser sintering (DMLS) process have been studied. Mainly, size and volume fraction of SiCp have been varied to analyze the crack and wear behavior of the composite. The study has suggested that crack density increases significantly after 15 volume percentage (vol.%) of SiCp. The paper has also suggested that when size (mesh) of reinforcement increases, wear resistance of the composite drops. Three hundred mesh of SiCp offers better wear resistance; above 300 mesh the specific wear rate increases significantly. Similarly, there has been no improvement of wear resistance after 20 vol.% of reinforcement. The scanning electron micrographs of the worn surfaces have revealed that during the wear test SiCp fragments into small pieces which act as abrasives to result in abrasive wear in the specimen.

For cermet inert anode containing oxide and metal phases useful for the electrolytic production of metals

Science.gov (United States)

Ray, Siba P.; Liu, Xinghua; Weirauch, Douglas A.

2002-01-01

A cermet inert anode for the electrolytic production of metals such as aluminum is disclosed. The inert anode comprises a ceramic phase including an oxide of Ni, Fe and M, where M is at least one metal selected from Zn, Co, Al, Li, Cu, Ti, V, Cr, Zr, Nb, Ta, W, Mo, Hf and rare earths, preferably Zn and/or Co. Preferred ceramic compositions comprise Fe.sub.2 O.sub.3, NiO and ZnO or CoO. The cermet inert anode also comprises a metal phase such as Cu, Ag, Pd, Pt, Au, Rh, Ru, Ir and/or Os. A preferred metal phase comprises Cu and Ag. The cermet inert anodes may be used in electrolytic reduction cells for the production of commercial purity aluminum as well as other metals.

Fabrication of mesoporous metal oxide coated-nanocarbon hybrid materials via a polyol-mediated self-assembly process

Science.gov (United States)

Feng, Bingmei; Wang, Huixin; Wang, Dongniu; Yu, Huilong; Chu, Yi; Fang, Hai-Tao

2014-11-01

After clarifying the formation mechanism of a typical metal glycolate precipitate, Ti glycolate, in a polyol-mediated synthesis using acetone as a precipitation medium, we describe a simple template-free approach based on an ethylene glycol-mediated synthesis to fabricate mesoporous metal oxide coated-nanocarbon hybrid materials including TiO2 coated-carbon nanotube (CNT), SnO2 coated-CNT, Cu2O/CuO coated-CNT and TiO2 coated-graphene sheet (GS). In the approach, metal oxide precursors, metal glycolates, were first deposited on CNTs or GSs, and subsequently transformed to the metal oxide coatings by pyrolysis or hydrolysis. By a comparison between the characterization of two TiO2-CNT hybrid materials using carboxylated CNTs and pristine CNTs without carboxyl groups, the driving force for initiating the deposition of metal glycolates on the carboxylated CNTs is confirmed to be the hydrogen bonding between the carboxyl groups and the polymer chains in metal glycolate sols. The electrochemical performances of the mesoporous TiO2 coated-carboxylated CNTs and TiO2-pristine CNT hybrid materials were investigated. The results show that the mesoporous TiO2 coated-carboxylated CNT with a uniform core-shell nanostructure exhibits substantial improvement in the rate performance in comparison with its counterpart from 0.5 C to 100 C because of its higher electronic conductivity and shorter diffusion path for the lithium ion. At the extremely high rate of 100 C, the specific capacity of TiO2 of the former reaches 85 mA h g-1, twice as high as that of the latter.After clarifying the formation mechanism of a typical metal glycolate precipitate, Ti glycolate, in a polyol-mediated synthesis using acetone as a precipitation medium, we describe a simple template-free approach based on an ethylene glycol-mediated synthesis to fabricate mesoporous metal oxide coated-nanocarbon hybrid materials including TiO2 coated-carbon nanotube (CNT), SnO2 coated-CNT, Cu2O/CuO coated-CNT and TiO2

Impact of heavy metals on the oil products biodegradation process.

Science.gov (United States)

Zukauskaite, Audrone; Jakubauskaite, Viktorija; Belous, Olga; Ambrazaitiene, Dalia; Stasiskiene, Zaneta

2008-12-01

Oil products continue to be used as a principal source of energy. Wide-scale production, transport, global use and disposal of petroleum have made them major contaminants in prevalence and quantity in the environment. In accidental spills, actions are taken to remove or remediate or recover the contaminants immediately, especially if they occur in environmentally sensitive areas, for example, in coastal zones. Traditional methods to cope with oil spills are confined to physical containment. Biological methods can have an advantage over the physical-chemical treatment regimes in removing spills in situ as they offer biodegradation of oil fractions by the micro-organisms. Recently, biological methods have been known to play a significant role in bioremediation of oil-polluted coastal areas. Such systems are likely to be of significance in the effective management of sensitive coastal ecosystems chronically subjected to oil spillage. For this reason the aim of this paper is to present an impact of Mn, Cu, Co and Mo quantities on oil biodegradation effectiveness in coastal soil and to determine the relationship between metal concentrations and degradation of two oil products (black oil and diesel fuel). Soil was collected in the Baltic Sea coastal zone oil products degradation area (Klaipeda, Lithuania). The experiment consisted of two parts: study on the influence of micro-elements on the oil product biodegradation process; and analysis of the influence of metal concentration on the number of HDMs. The analysis performed and results obtained address the following areas: impact of metal on a population of hydrocarbon degrading micro-organisms, impact of metals on residual concentrations of oil products, influence of metals on the growth of micro-organisms, inter-relation of metal concentrations with degradation rates. Statistical analysis was made using ;Statgraphics plus' software. The influence of metals on the growth of micro-organisms, the biodegradation process

A Metal Matrix CNTS Modified Electrode Fabricated Using Micromachining-Based Implantation Method for Improving Sensitivity and Stability

Directory of Open Access Journals (Sweden)

Yan Wang

2013-01-01

Full Text Available The metal matrix carbon nanotubes modified electrode (MCME has been fabricated by a novel process involving preparation of carbon nanotubes (CNTs/polyimide (PI composite film, wet, etching, sputtering, electroplating, and wet-etch releasing. Pretreated CNTs are dispersed in PI by mechanical ball milling and then CNTs solution is spin-coated on the substrate. The CNTs/PI composite film is etched away a layer of PI to expose tips of CNTs using buffering solution. These exposed tips of CNTs are covered by metal particles in sputtering process as metal seed layer, followed by metal supporting film formed by electroplating. The MCME is obtained after releasing PI film from the metal supporting film. The MCME shows well morphology of uniform distributional protruding tips of CNTs and increased electron transfer efficiency with strong bonding connection between CNTs and metal matrix, which greatly improves sensitivity and stability of the MCME. The oxidation peak of the MCME in cyclic voltammeter (CV test is 1.7 times more than that of CNTs suspension spin-coated metal electrode (SCME. The decline of peak current of the MCME after fifty cycles is only 1.8% much less than 67% of the SCME. Better sensitivity and stability may be helpful for CNTs modified electrodes wide application for trace test of many special materials.

Production of aluminum metal by electrolysis of aluminum sulfide

Science.gov (United States)

Minh, Nguyen Q.; Loutfy, Raouf O.; Yao, Neng-Ping

1984-01-01

Production of metallic aluminum by the electrolysis of Al.sub.2 S.sub.3 at 700.degree.-800.degree. C. in a chloride melt composed of one or more alkali metal chlorides, and one or more alkaline earth metal chlorides and/or aluminum chloride to provide improved operating characteristics of the process.

Comparative Study of Laboratory-Scale and Prototypic Production-Scale Fuel Fabrication Processes and Product Characteristics

International Nuclear Information System (INIS)

Marshall, Douglas W.

2014-01-01

An objective of the High Temperature Gas Reactor fuel development and qualification program for the United States Department of Energy has been to qualify fuel fabricated in prototypic production-scale equipment. The quality and characteristics of the tristructural isotropic (TRISO) coatings on fuel kernels are influenced by the equipment scale and processing parameters. The standard deviations of some TRISO layer characteristics were diminished while others have become more significant in the larger processing equipment. The impact on statistical variability of the processes and the products, as equipment was scaled, are discussed. The prototypic production-scale processes produce test fuels meeting all fuel quality specifications. (author)

Metal-doped single-walled carbon nanotubes and production thereof

Science.gov (United States)

Dillon, Anne C.; Heben, Michael J.; Gennett, Thomas; Parilla, Philip A.

2007-01-09

Metal-doped single-walled carbon nanotubes and production thereof. The metal-doped single-walled carbon nanotubes may be produced according to one embodiment of the invention by combining single-walled carbon nanotube precursor material and metal in a solution, and mixing the solution to incorporate at least a portion of the metal with the single-walled carbon nanotube precursor material. Other embodiments may comprise sputter deposition, evaporation, and other mixing techniques.

Fabricating plasmonic components for nano-and meta-photonics

DEFF Research Database (Denmark)

Boltasseva, Alexandra; Nielsen, Rasmus Bundgaard; Jeppesen, Claus

2009-01-01

Different fabrication approaches for realization of metal-dielectric structures supporting propagating and localized surface plasmons are described including fabrication of nanophotonic waveguides and plasmonic nanoantennae....

Ion traps fabricated in a CMOS foundry

Energy Technology Data Exchange (ETDEWEB)

Mehta, K. K.; Ram, R. J. [Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Eltony, A. M.; Chuang, I. L. [Center for Ultracold Atoms, Research Laboratory of Electronics and Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Bruzewicz, C. D.; Sage, J. M., E-mail: jsage@ll.mit.edu; Chiaverini, J., E-mail: john.chiaverini@ll.mit.edu [Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, Massachusetts 02420 (United States)

2014-07-28

We demonstrate trapping in a surface-electrode ion trap fabricated in a 90-nm CMOS (complementary metal-oxide-semiconductor) foundry process utilizing the top metal layer of the process for the trap electrodes. The process includes doped active regions and metal interconnect layers, allowing for co-fabrication of standard CMOS circuitry as well as devices for optical control and measurement. With one of the interconnect layers defining a ground plane between the trap electrode layer and the p-type doped silicon substrate, ion loading is robust and trapping is stable. We measure a motional heating rate comparable to those seen in surface-electrode traps of similar size. This demonstration of scalable quantum computing hardware utilizing a commercial CMOS process opens the door to integration and co-fabrication of electronics and photonics for large-scale quantum processing in trapped-ion arrays.

Development of metallic fuel fabrication

Energy Technology Data Exchange (ETDEWEB)

Kang, Young Ho; Lee, Chong Yak; Lee, Myung Ho and others

1999-03-01

With the vacuum melting and casting of the U-10wt%Zr alloy which is metallic fuel for liquid metal fast breeder reactor, we studied the microstructure of the alloy and the parameters of the melting and casting for the fuel rods. Internal defects of the U-10wt%Zr fuel by gravity casting, were inspected by non-destructive test. U-10wt%Zr alloy has been prepared for the thermal stability test in order to estimate the decomposition of the lamellar structure with relation to swelling under irradiation condition. (author)

Cold-crucible fabrication of nuclear glasses

International Nuclear Information System (INIS)

Boen, R.

2010-01-01

Vitrification has stood the nuclear industry in good stead, for many years now, as a safe long-term conditioning technology for high-level waste. Major advances are nonetheless still being made, with the development of the cold-crucible technology, affording as it does new possibilities, in terms of volume reduction, and of extending the range of waste products amenable to incorporation. Indeed, by allowing higher melting temperatures to be achieved (1200 - 1400 C degrees), this process opens the way to a considerable increase in glass production capacities, and the fabrication of novel matrices, involving higher incorporation rates than current glasses. In the cold-crucible technology, materials put into the crucible are heated directly through induction. The crucible made of metal is cooled by water circulation. Where the glass comes into contact with the cold wall, a thin layer of solidified glass forms, with a thickness of 5-10 mm preventing the metal forming the crucible from coming into contact with the molten glass. A full scale pilot of the cold crucible was constructed at the La Hague vitrification workshop

Updated Life-Cycle Assessment of Aluminum Production and Semi-fabrication for the GREET Model

Energy Technology Data Exchange (ETDEWEB)

Dai, Qiang [Argonne National Lab. (ANL), Argonne, IL (United States); Kelly, Jarod C. [Argonne National Lab. (ANL), Argonne, IL (United States); Burnham, Andrew [Argonne National Lab. (ANL), Argonne, IL (United States); Elgowainy, Amgad [Argonne National Lab. (ANL), Argonne, IL (United States)

2015-09-01

This report serves as an update for the life-cycle analysis (LCA) of aluminum production based on the most recent data representing the state-of-the-art of the industry in North America. The 2013 Aluminum Association (AA) LCA report on the environmental footprint of semifinished aluminum products in North America provides the basis for the update (The Aluminum Association, 2013). The scope of this study covers primary aluminum production, secondary aluminum production, as well as aluminum semi-fabrication processes including hot rolling, cold rolling, extrusion and shape casting. This report focuses on energy consumptions, material inputs and criteria air pollutant emissions for each process from the cradle-to-gate of aluminum, which starts from bauxite extraction, and ends with manufacturing of semi-fabricated aluminum products. The life-cycle inventory (LCI) tables compiled are to be incorporated into the vehicle cycle model of Argonne National Laboratory’s Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) Model for the release of its 2015 version.

Mass production of polymer nano-wires filled with metal nano-particles.

Science.gov (United States)

Lomadze, Nino; Kopyshev, Alexey; Bargheer, Matias; Wollgarten, Markus; Santer, Svetlana

2017-08-17

Despite the ongoing progress in nanotechnology and its applications, the development of strategies for connecting nano-scale systems to micro- or macroscale elements is hampered by the lack of structural components that have both, nano- and macroscale dimensions. The production of nano-scale wires with macroscale length is one of the most interesting challenges here. There are a lot of strategies to fabricate long nanoscopic stripes made of metals, polymers or ceramics but none is suitable for mass production of ordered and dense arrangements of wires at large numbers. In this paper, we report on a technique for producing arrays of ordered, flexible and free-standing polymer nano-wires filled with different types of nano-particles. The process utilizes the strong response of photosensitive polymer brushes to irradiation with UV-interference patterns, resulting in a substantial mass redistribution of the polymer material along with local rupturing of polymer chains. The chains can wind up in wires of nano-scale thickness and a length of up to several centimeters. When dispersing nano-particles within the film, the final arrangement is similar to a core-shell geometry with mainly nano-particles found in the core region and the polymer forming a dielectric jacket.

Three-dimensional metamaterials fabricated using Proton Beam Writing

Energy Technology Data Exchange (ETDEWEB)

Bettiol, A.A., E-mail: a.bettiol@nus.edu.sg [Centre for Ion Beam Applications, Department of Physics, National University of Singapore, 2 Science Dr. 3, Singapore 117542 (Singapore); Turaga, S.P.; Yan, Y.; Vanga, S.K. [Centre for Ion Beam Applications, Department of Physics, National University of Singapore, 2 Science Dr. 3, Singapore 117542 (Singapore); Chiam, S.Y. [NUS High School for Maths and Science, 20 Clementi Avenue 1, Singapore 129957 (Singapore)

2013-07-01

Proton Beam Writing (PBW) is a direct write lithographic technique that has recently been applied to the fabrication of three dimensional metamaterials. In this work, we show that the unique capabilities of PBW, namely the ability to fabricate arrays of high resolution, high aspect ratio microstructures in polymer or replicated into metal, is well suited to metamaterials research. We have also developed a novel method for selectively electroless plating silver directly onto polymer structures that were fabricated using PBW. This method opens up new avenues for utilizing PBW for making metamaterials and other sub-wavelength metallic structures. Several potential applications of three dimensional metamaterials fabricated using PBW are discussed, including sensing and negative refractive index materials.

Fabrication of Metallic Glass Powder for Brazing Paste for High-Temperature Thermoelectric Modules

Science.gov (United States)

Seo, Seung-Ho; Kim, Suk Jun; Lee, Soonil; Seo, Won-Seon; Kim, Il-Ho; Choi, Soon-Mok

2018-06-01

Metallic glass (MG) offers the advantage of outstanding oxidation resistance, since it has disordered atomic-scale structure without grain boundaries. We fabricated Al-based MG ribbons (Al84.5Y10Ni5.5) by a melt spinning process. We evaluated the adhesion strength of interfaces between the Al-based MG and a Ni-coated Cu electrode formed under various conditions at high temperature. In addition, we attempted to optimize the process conditions for pulverizing MG ribbons to high-energy ball milling and planetary milling. We confirmed that the electrical resistivity of the Al-based MG ribbon was substantially reduced after annealing at high temperature (over 300°C) due to crystallization.

Sorption techniques for production of high purity refractory metals

International Nuclear Information System (INIS)

Shatalov, V.V.; Peganov, V.A.; Logvinenko, I.A.; Molchanova, T.V.

2004-01-01

A consideration is given to potentialities of sorption processes tot provide a high quality of refractory metal and their alloys when using hydrometallurgical methods for raw material processing. The efficiency of application of ion exchange technology is shown for complex solutions reprocessing for various types of polymetallic raw materials, among them uranium ores, enriched concentrates of refractory metal ores, intermediate products, waste solutions. Based on investigation results on the behaviour of elements in process solutions and the mechanism of their sorption and elution, the process of pure chemical compounds production are developed which provide thereafter manufacturing compact metals. The flowsheets developed are mastered on a commercial scale [ru

Fabrication and Optical Characterization of Silicon Nanostructure Arrays by Laser Interference Lithography and Metal-Assisted Chemical Etching

Directory of Open Access Journals (Sweden)

P. Heydari

2014-10-01

Full Text Available In this paper metal-assisted chemical etching has been applied to pattern porous silicon regions and silicon nanohole arrays in submicron period simply by using positive photoresist as a mask layer. In order to define silicon nanostructures, Metal-assisted chemical etching (MaCE was carried out with silver catalyst. Provided solution (or materiel in combination with laser interference lithography (LIL fabricated different reproducible pillars, holes and rhomboidal structures. As a result, Submicron patterning of porous areas and nanohole arrays on Si substrate with a minimum feature size of 600nm was achieved. Measured reflection spectra of the samples present different optical characteristics which is dependent on the shape, thickness of metal catalyst and periodicity of the structure. These structures can be designed to reach a photonic bandgap in special range or antireflection layer in energy harvesting applications. The resulted reflection spectra of applied method are comparable to conventional expensive and complicated dry etching techniques.

Additive manufacturing technology (direct metal laser sintering) as a novel approach to fabricate functionally graded titanium implants: preliminary investigation of fabrication parameters.

Science.gov (United States)

Lin, Wei-Shao; Starr, Thomas L; Harris, Bryan T; Zandinejad, Amirali; Morton, Dean

2013-01-01

This article describes the preliminary findings of the mechanical properties of functionally graded titanium with controlled distribution of porosity and a reduced Young's modulus on the basis of a computeraided design (CAD) file, using the rapid-prototyping, direct metal laser sintering (DMLS) technique. Sixty specimens of Ti-6Al-4V were created using a DMLS machine (M270) following the standard for tensile testing of metals. One group was fabricated with only 170 W of laser energy to create fully dense specimens (control group). The remaining specimens all featured an outer fully dense "skin" layer and a partially sintered porous inner "core" region. The outer "skin" of each specimen was scanned at 170 W and set at a thickness of 0.35, 1.00, or 1.50 mm for different specimen groups. The inner "core" of each specimen was scanned at a lower laser power (43 or 85 W). The partially sintered core was clearly visible in all specimens, with somewhat greater porosity with the lower laser power. However, the amount of porosity in the core region was not related to the laser power alone; thinner skin layers resulted in higher porosity for the same power values in the core structure. The lowest Young's modulus achieved, 35 GPa, is close to that of bone and was achieved with a laser power of 43 W and a skin thickness of 0.35 mm, producing a core that comprised 74% of the total volume. Additive manufacturing technology may provide an efficient alternative way to fabricate customized dental implants based on a CAD file with a functionally graded structure that may minimize stress shielding and improve the long-term performance of dental implants.

Alternative fabrication scheme to study effects of rework of nonconforming products and delayed differentiation on a multiproduct supply-chain system

Directory of Open Access Journals (Sweden)

Yuan-Shyi Peter Chiu

2017-07-01

Full Text Available This study uses an alternative fabrication scheme to study the effect of rework of nonconforming items and delayed differentiation on a multiproduct supply-chain system. Traditional economic production quantity model focuses on a single-product inventory system where all products made are assumed to be perfect quality and finished products are issued continuously. To increase machine utilization, lower quality costs in production, and reflect the real-world vendor-buyer integrated systems Chiu et al. (2016a [Chiu, Y-S.P., Kuo, J-S., Chiu, S. W., Hsieh, Y-T. (2016a. Effect of delayed differentiation on a multiproduct vendor–buyer integrated inventory system with rework. Advances in Production Engineering & Management, 11(4, 333-344.] employed a single-machine two-stage production scheme to study the effects of rework and delayed differentiation on a multi-product supply-chain system. With the intention of further reducing fabrication cycle time, this study considers an alternative two-machine two-stage fabrication scheme to re-explore the problem in Chiu et al. (2016a. Machine one solely produces all common parts for multiple end products. Then, machine two fabricates the customized multiproduct using a common cycle time strategy. Through the use of mathematical modeling and analyses, the optimal production cycle length and distribution policy are derived. Numerical examples are provided to demonstrate practical usage of the research results, and show its significant benefit in reducing fabrication cycle time compared to that obtained from prior studies that used different schemes.

Analysis of toxic metals in branded Pakistani herbal products

International Nuclear Information System (INIS)

Saeed, M.; Muhammad, N.; Khan, H.

2010-01-01

The present study was designed to estimate the concentration of heavy toxic metals in Pakistani herbal products frequently used for the treatment of various ailments. For this purpose, twenty five herbal products of well reputed herbal manufacturers were selected. The results of our investigation revealed that the concentrations of lead, cadmium, nickel and chromium were far beyond the permissible limits proposed by the International Regulatory Authorities for herbal drugs. Therefore, this study conveys a strong message to the ministry of health to establish proper rules and regulations for the validation of herbal products on scientific grounds in order to protect the general public from the harmful effects of these heavy metals in herbal products. (author)

Low-Cost and Rapid Fabrication of Metallic Nanostructures for Sensitive Biosensors Using Hot-Embossing and Dielectric-Heating Nanoimprint Methods

Directory of Open Access Journals (Sweden)

Kuang-Li Lee

2017-07-01

Full Text Available We propose two approaches—hot-embossing and dielectric-heating nanoimprinting methods—for low-cost and rapid fabrication of periodic nanostructures. Each nanofabrication process for the imprinted plastic nanostructures is completed within several seconds without the use of release agents and epoxy. Low-cost, large-area, and highly sensitive aluminum nanostructures on A4 size plastic films are fabricated by evaporating aluminum film on hot-embossing nanostructures. The narrowest bandwidth of the Fano resonance is only 2.7 nm in the visible light region. The periodic aluminum nanostructure achieves a figure of merit of 150, and an intensity sensitivity of 29,345%/RIU (refractive index unit. The rapid fabrication is also achieved by using radio-frequency (RF sensitive plastic films and a commercial RF welding machine. The dielectric-heating, using RF power, takes advantage of the rapid heating/cooling process and lower electric power consumption. The fabricated capped aluminum nanoslit array has a 5 nm Fano linewidth and 490.46 nm/RIU wavelength sensitivity. The biosensing capabilities of the metallic nanostructures are further verified by measuring antigen–antibody interactions using bovine serum albumin (BSA and anti-BSA. These rapid and high-throughput fabrication methods can benefit low-cost, highly sensitive biosensors and other sensing applications.

Marginal accuracy of nickel chromium copings fabricated by conventional and accelerated casting procedures, produced with ringless and metal ring investment procedures: A comparative in vitro study

Directory of Open Access Journals (Sweden)

Deepa Alex

2015-01-01

Conclusion: The Ni-Cr cast copings fabricated with the conventional casting using ringless investment system showed significantly better marginal fit than that of cast copings fabricated from conventional and accelerated casting with metal ring investment and accelerated casting using ringless investment since those copings had shown the least vertical marginal discrepancies among the four methods evaluated in this study.

Fabrication and non-covalent modification of highly oriented thin films of a zeolite-like metal-organic framework (ZMOF) with rho topology

KAUST Repository

Shekhah, Osama; Cadiau, Amandine; Eddaoudi, Mohamed

2015-01-01

Here we report the fabrication of the first thin film of a zeolite-like metal-organic framework (ZMOF) with rho topology (rho-ZMOF-1, ([In48(HImDC)96]48-)n) in a highly oriented fashion on a gold-functionalized substrate. The oriented rho-ZMOF-1

Fabrication and Microstructure of Metal-Metal Syntactic Foams

National Research Council Canada - National Science Library

Nadler, J

1998-01-01

.... The composite microstructure consists of thin-wall, hollow Fe-Cr stainless steel spheres cast in various metal matrices including aluminum alloys 6061, 7075, 413, magnesium alloy AZ31B, and unalloyed...

Irradiation tests of 99Mo isotope production targets employing uranium metal foils

International Nuclear Information System (INIS)

Hofman, G.L.; Wiencek, T.C.; Wood, E.L.; Snelgrove, J.L.; Suripto, A.; Nasution, H.; Lufti-Amin, D.; Gogo, A.

1996-01-01

Most of the world's supply of 99 mTc for medical purposes is currently produced from the decay of 99 Mo derived from the fissioning of high-enriched uranium (HEU). Substitution of low-enriched uranium (LEU) metal foils for the HEU UO 2 used in current target designs will allow equivalent 99 Mo yields with little change in target geometries. Substitution of uranium metal for uranium alloy and aluminide in other target designs will also allow the conversion of HEU to LEU. Several uranium-metal-foil targets have been fabricated at ANL and irradiated to prototypic burnup in the Indonesian RSG-GAS reactor. Postirradiation examination of the initial test indicated that design modifications were required to allow the irradiated foil to be removed for chemical processing. The latest test has shown good irradiation behavior, satisfactory dismantling and foil removal when the U-foil is separated from its containment by metallic, fission-recoil absorbing barriers. (author)

Irradiation tests of 99Mo isotope production targets employing uranium metal foils

International Nuclear Information System (INIS)

Hofman, G.L.; Wiencek, T.C.; Wood, E.L.; Snelgrove, J.L.; Suripto, A.; Nasution, H.; Lufti-Amin, D.; Gogo, A.

1996-01-01

Most of the world's supply of 99m Tc for medical purposes is currently produced form the decay of 99 Mo derived from the fissioning of high-enriched uranium (HEU). Substitution of low-enriched uranium (LEU) metal foils for the HEU UO 2 used in current target designs will allow equivalent 99 Mo yields with little change in target geometries. Substitution of uranium metal for uranium alloy and aluminide in other target designs will also allow the conversion of HEU to LEU. Several uranium-metal-foil targets have been fabricated at ANL and irradiated to prototypic burnup in the Indonesian RSG-GAS reactor. Postirradiation examination of the initial test indicated that design modifications were required to allow the irradiated foil to be removed for chemical processing. The latest test has shown good irradiation behavior, satisfactory dismantling and foil removal when the U-foil is separated from its containment by metallic, fission-recoil absorbing barriers

Status of Research on Selective Laser Sintering of Nanomaterials for Flexible Electronics Fabrication

International Nuclear Information System (INIS)

Ko, Seung Hwan

2011-01-01

A plastic-compatible low-temperature metal deposition and patterning process is essential for the fabrication of flexible electronics because they are usually built on a heat-sensitive flexible substrate, for example plastic, fabric, paper, or metal foil. There is considerable interest in solution-processible metal nanoparticle ink deposition and patterning by selective laser sintering. It provides flexible electronics fabrication without the use of conventional photolithography or vacuum deposition techniques. We summarize our recent progress on the selective laser sintering of metals and metal oxide nanoparticles on a polymer substrate to realize flexible electronics such as flexible displays and flexible solar cells. Future research directions are also discussed

From Oxygen Generation to Metals Production: In Situ Resource Utilization by Molten Oxide Electrolysis

Science.gov (United States)

Khetpal, Deepak; Ducret, Andrew C.; Sadoway, Donald R.

2003-01-01

For the exploration of other bodies in the solar system, electrochemical processing is arguably the most versatile technology for conversion of local resources into usable commodities: by electrolysis one can, in principle, produce (1) breathable oxygen, (2) silicon for the fabrication of solar cells, (3) various reactive metals for use as electrodes in advanced storage batteries, and (4) structural metals such as steel and aluminum. Even so, to date there has been no sustained effort to develop such processes, in part due to the inadequacy of the database. The objective here is to identify chemistries capable of sustaining molten oxide electrolysis in the cited applications and to examine the behavior of laboratory-scale cells designed to generate oxygen and to produce metal. The basic research includes the study of the underlying high-temperature physical chemistry of oxide melts representative of lunar regolith and of Martian soil. To move beyond empirical approaches to process development, the thermodynamic and transport properties of oxide melts are being studied to help set the limits of composition and temperature for the processing trials conducted in laboratory-scale electrolysis cells. The goal of this investigation is to deliver a working prototype cell that can use lunar regolith and Martian soil to produce breathable oxygen along with metal by-product. Additionally, the process can be generalized to permit adaptation to accommodate different feedstock chemistries, such as those that will be encountered on other bodies in the solar system. The expected results of this research include: (1) the identification of appropriate electrolyte chemistries; (2) the selection of candidate anode and cathode materials compatible with electrolytes named above; and (3) performance data from a laboratory-scale cell producing oxygen and metal. On the strength of these results it should be possible to assess the technical viability of molten oxide electrolysis for in

Interactive influences of bioactive trace metals on biological production in oceanic waters

International Nuclear Information System (INIS)

Bruland, K.W.; Donat, J.R.; Hutchins, D.A.

1991-01-01

The authors present an overview of the oceanic chemistries of the bioactive trace metals, Mn, Fe, Co, Ni, Cu, and Zn; the authors combine field data with results from laboratory phytoplankton culture-trace metal studies and speculate on the potential influences of these trace metals on oceanic plankton production and species composition. Most field studies have focused on the effects of single metals. However, they propose that synergistic and antagonistic interactions between multiple trace metals could be very important in the oceans. Trace metal antagonisms that may prove particularly important are those between Cu and the potential biolimiting metals Fe, Mn, and Zn. These antagonistic interactions could have the greatest influence on biological productivity in areas of the open ocean isolated from terrestrial inputs, such as the remote high nutrient regions of the Pacific and Antarctic Oceans. The emerging picture of trace metal-biota interactions in these oceanic areas is one in which biology strongly influences distribution and chemical speciation of all these bioactive trace metals. It also seems likely that many of these bioactive trace metals and their speciation may influence levels of primary productivity, species composition, and trophic structure. Future investigations should give more complete consideration to the interactive effects of biologically important trace metals

Current developments of fuel fabrication technologies at the plutonium fuel production facility, PFPF

International Nuclear Information System (INIS)

Asakura, K.; Aono, S.; Yamaguchi, T.; Deguchi, M.

2000-01-01

The Japan Nuclear Cycle Development Institute, JNC, designed, constructed and has operated the Plutonium Fuel Production Facility, PFPF, at the JNC Tokai Works to supply MOX fuels to the proto-type Fast Breeder Reactor, FBR, 'MONJU' and the experimental FBR 'JOYO' with 5 tonMOX/year of fabrication capability. Reduction of personal radiation exposure to a large amount of plutonium is one of the most important subjects in the development of MOX fabrication facility on a large scale. As the solution of this issue, the PFPF has introduced automated and/or remote controlled equipment in conjunction with computer controlled operation scheme. The PFPF started its operation in 1988 with JOYO reload fuel fabrication and has demonstrated MOX fuel fabrication on a large scale through JOYO and MONJU fuel fabrication for this decade. Through these operations, it has become obvious that several numbers of equipment initially installed in the PFPF need improvements in their performance and maintenance for commercial utilization of plutonium in the future. Furthermore, fuel fabrication of low density MOX pellets adopted in the MONJU fuel required a complete inspection because of difficulties in pellet fabrication compared with high density pellet for JOYO. This paper describes new pressing equipment with a powder recovery system, and pellet finishing and inspection equipment which has multiple functions, such as grinding measurements of outer diameter and density, and inspection of appearance to improve efficiency in the pellet finishing and inspection steps. Another development of technology concerning an annular pellet and an innovative process for MOX fuel fabrication are also described in this paper. (author)

Synthesis, fabrication, and spectroscopy of nano-scale photonic noble metal materials

Science.gov (United States)

Egusa, Shunji

Nanometer is an interesting scale for physicists, chemists, and materials scientists, in a sense that it lies between the macroscopic and the atomic scales. In this regime, materials exhibit distinct physical and chemical properties that are clearly different from those of atoms or macroscopic bulk. This thesis is concerned about both physics and chemistry of noble metal nano-structures. Novel chemical syntheses and physical fabrications of various noble metal nano-structures, and the development of spectroscopic techniques for nano-structures are presented. Scanning microscopy/spectroscopy techniques inherently perturbs the true optical responses of the nano-structures. However, by using scanning tunneling microscope (STM) tip as the nanometer-confined excitation source of surface plasmons in the samples, and subsequently collecting the signals in the Fourier space, it is shown that the tip-perturbed part of the signals can be deconvoluted. As a result, the collected signal in this approach is the pure response of the sample. Coherent light is employed to study the optical response of nano-structures, in order to avoid complication from tip-perturbation as discussed above. White-light super-continuum excites the nano-structure, the monolayer of Au nanoparticles self-assembled on silicon nitride membrane substrates. The coherent excitation reveals asymmetric surface plasmon resonance in the nano-structures. One of the most important issues in nano-scale science is to gain control over the shape, size, and assembly of nanoparticles. A novel method is developed to chemically synthesize ligand-passivated atomic noble metal clusters in solution phase. The method, named thermal decomposition method, enables facile yet robust synthesis of fluorescent atomic clusters. Thus synthesized atomic clusters are very stable, and show behaviors of quantum dots. A novel and versatile approach for creation of nanoparticle arrays is developed. This method is different from the

APPARATUS FOR THE PRODUCTION OF LITHIUM METAL

Science.gov (United States)

Baker, P.S.; Duncan, F.R.; Greene, H.B.

1961-08-22

Methods and apparatus for the production of high-purity lithium from lithium halides are described. The apparatus is provided for continuously contacting a molten lithium halide with molten barium, thereby forming lithium metal and a barium halide, establishing separate layers of these reaction products and unreacted barium and lithium halide, and continuously withdrawing lithium and barium halide from the reaction zone. (AEC)

Development of IN-RAFM steel and fabrication technologies for Indian TBM

Energy Technology Data Exchange (ETDEWEB)

Albert, S.K., E-mail: shaju@igcar.gov.in [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam 603 102 (India); Laha, K.; Bhaduri, A.K.; Jayakumar, T. [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam 603 102 (India); Rajendrakumar, E. [TBM Division, Institute of Plasma Research, Bhat, Gandhinagar 382428 (India)

2016-11-01

Highlights: • India specific RAFM steel IN-RAFM has been produced in commercial scale and physical property data for the same have been generated. • Mechanical properties of the commercial heats are comparable to that of the laboratory heats. • IN-RAFM steel filler wires has been produced indigenously. • Process parameters have been optimized so that toughness of the fusion zone of the EB and laser welds is comparable to that of the base metal even at sub-zero temperatures. • Fabrication of the mock ups of different components of Indian TBM has been initiated. - Abstract: India has indigenously developed its own Indian Reduced Activation Ferritic Martensitic Steel (IN-RAFM steel) which, it is proposed to use for fabrication of Indian TBM to be installed in ITER. With an objective of qualifying this material for use in ITER, extensive testing of this material to generate the necessary data required to offer this material for Particular Material Appraisal of ITER has been undertaken. Accordingly, data generation on creep, fatigue and physical properties of this steel is in progress. Physical properties like thermal diffusivity, heat capacity and thermal expansion coefficient for this steel at various temperatures have been measured and thermal conductivity estimated from the measured physical properties. Values obtained for these physical properties are comparable with those reported for other RAFM steels. Results of creep tests that are in progress also indicate that creep is comparable to that of other RAFM steels. Low cycle fatigue (LCF) behaviour of this steel has been studied in air with total strain control in the strain amplitude range of ±0.25–1% and temperatures range of 300–873 K at a constant strain rate of 3 × 10{sup −3} s{sup −1}. Results confirm that fatigue life of IN-RAFM steel is at par with that of the European Union grade Eurofer 97 RAFM steel. During production of IN-RAFM steel plates of different thicknesses, it is observed

Modernity Evaluation of the Machines Used During Production Process of Metal Products

OpenAIRE

Ingaldi, Manuela; Dziuba, Szymon T.

2015-01-01

Most manufacturing companies realize its technologies, implemented through concrete machinery parts. They differ in terms of importance, the relevance of their selection and the level of their modernity. Modernity and efficiency of the machine are also very important during production process of the metal products. They have an influence on the quality of these products. The purpose of this article is to analyse the chosen production machine (CNC machine AFE-3D8-T) used during pro...

Understanding the Thermal Properties of Precursor-Ionomers to Optimize Fabrication Processes for Ionic Polymer-Metal Composites (IPMCs

Directory of Open Access Journals (Sweden)

Sarah Trabia

2018-04-01

Full Text Available Ionic polymer-metal composites (IPMCs are one of many smart materials and have ionomer bases with a noble metal plated on the surface. The ionomer is usually Nafion, but recently Aquivion has been shown to be a promising alternative. Ionomers are available in the form of precursor pellets. This is an un-activated form that is able to melt, unlike the activated form. However, there is little study on the thermal characteristics of these precursor ionomers. This lack of knowledge causes issues when trying to fabricate ionomer shapes using methods such as extrusion, hot-pressing, and more recently, injection molding and 3D printing. To understand the two precursor-ionomers, a set of tests were conducted to measure the thermal degradation temperature, viscosity, melting temperature, and glass transition. The results have shown that the precursor Aquivion has a higher melting temperature (240 °C than precursor Nafion (200 °C and a larger glass transition range (32–65°C compared with 21–45 °C. The two have the same thermal degradation temperature (~400 °C. Precursor Aquivion is more viscous than precursor Nafion as temperature increases. Based on the results gathered, it seems that the precursor Aquivion is more stable as temperature increases, facilitating the manufacturing processes. This paper presents the data collected to assist researchers in thermal-based fabrication processes.

Effect of metal ions on the growth and metabolites production of ...

African Journals Online (AJOL)

Effect of metal ions on the growth and metabolites production of Ganoderma lucidum in submerged culture. YH Cui, KC Zhang. Abstract. The effects of several metal ions on the cell growth, production of polysaccharides by Ganoderma lucidum in submerged fermentation were studied. The results showed that 50 ppm Se2+ ...

Microscale metallization on conducting polyaniline patterns

International Nuclear Information System (INIS)

Uh, Kyung Chan; Lee, Joosub; Kim, Tae Geun; Lee, Chan Woo; Kim, Jong Man

2016-01-01

Fabrication of metallic nanomaterial patterns is very important in the electronic industry. A variety of techniques for producing these metallic nanoparticle patterns have been developed, such as ink-jet printing, 2 direct writing, 3,4 electroplati ng, 5,6 screen printing, 7 and soft lithography including micro-contact printing (μCP) 8–10 and we developed a simple and facile strategy for the fabrication of silver micropatterns on the surface of PANI patterns which were prepared by employing a photo- lithographic method. The silver was metallized along the PANI pattern through the oxidation-reduction reaction without requiring any reducing agent. The straightforward approach described above could open new avenues for the fabrication of metal micropatterns

Microscale metallization on conducting polyaniline patterns

Energy Technology Data Exchange (ETDEWEB)

Uh, Kyung Chan; Lee, Joosub; Kim, Tae Geun; Lee, Chan Woo; Kim, Jong Man [Hanyang University, Seoul (Korea, Republic of)

2016-12-15

Fabrication of metallic nanomaterial patterns is very important in the electronic industry. A variety of techniques for producing these metallic nanoparticle patterns have been developed, such as ink-jet printing, 2 direct writing, 3,4 electroplati ng, 5,6 screen printing, 7 and soft lithography including micro-contact printing (μCP) 8–10 and we developed a simple and facile strategy for the fabrication of silver micropatterns on the surface of PANI patterns which were prepared by employing a photo- lithographic method. The silver was metallized along the PANI pattern through the oxidation-reduction reaction without requiring any reducing agent. The straightforward approach described above could open new avenues for the fabrication of metal micropatterns.

Quantum confinement effect in cheese like silicon nano structure fabricated by metal induced etching

Energy Technology Data Exchange (ETDEWEB)

Saxena, Shailendra K., E-mail: phd1211512@iiti.ac.in; Sahu, Gayatri; Sagdeo, Pankaj R.; Kumar, Rajesh [Material Research Laboratory, Discipline of Physics & MSEG, Indian Institute of Technology Indore, Madhya Pradesh-452017 (India)

2015-08-28

Quantum confinement effect has been studied in cheese like silicon nano-structures (Ch-SiNS) fabricated by metal induced chemical etching using different etching times. Scanning electron microscopy is used for the morphological study of these Ch-SiNS. A visible photoluminescence (PL) emission is observed from the samples under UV excitation at room temperature due to quantum confinement effect. The average size of Silicon Nanostructures (SiNS) present in the samples has been estimated by bond polarizability model using Raman Spectroscopy from the red-shift observed from SiNSs as compared to its bulk counterpart. The sizes of SiNS present in the samples decreases as etching time increase from 45 to 75 mintunes.

Characterization of Schottky barrier diodes fabricated from electrochemical oxidation of {alpha} phase brass

Energy Technology Data Exchange (ETDEWEB)

Bond, John W., E-mail: jwb13@le.ac.u [Forensic Research Centre, University of Leicester, Leicester LE1 7 EA (United Kingdom)

2011-04-01

By careful selection of chloride ion concentration in aqueous sodium chloride, electrochemical oxidation of {alpha} phase brass is shown to permit fabrication of either p-type copper (I) oxide/metal or n-type zinc oxide/metal Schottky barrier diodes. X-ray photoelectron and Auger electron spectroscopies provide evidence that barrier formation and rectifying qualities depend on the relative surface abundance of copper (I) oxide and zinc oxide. X-ray diffraction of the resulting diodes shows polycrystalline oxides embedded in amorphous oxidation products that have a lower relative abundance than the diode forming oxide. Conventional I/V characteristics of these diodes show good rectifying qualities. When neither of the oxides dominate, the semiconductor/metal junction displays an absence of rectification.

Antibacterial properties of modified biodegradable PHB non-woven fabric.

Science.gov (United States)

Slepička, P; Malá, Z; Rimpelová, S; Švorčík, V

2016-08-01

The antibacterial properties of poly(hydroxybutyrate) (PHB) non-woven fabric were explored in this study. The PHB was activated by plasma modification and subsequently processed with either immersion into a solution of nanoparticles or direct metallization. The wettability and surface chemistry of the PHB surface was determined. The thickness of the sputtered nanolayer on PHB fabric was characterized. It was found that plasma modification led to a formation of strongly hydrophilic surface, while the subsequent metallization by silver or gold resulted in a significantly increased water contact angle. Further, it was found that antibacterial activity may be controlled by the type of a metal and deposition method used. The immersion of plasma modified fabric into Ag nanoparticle solution led to enhanced antibacterial efficiency of PHB against Escherichia coli (E. coli). Direct silver sputtering on PHB fabric was proved to be a simple method for construction of a surface with strong antibacterial potency against both Escherichia coli (E. coli) and Staphylococcus epidermidis (S. epidermidis). We demonstrated the antibacterial activity of PHB fabric modified by plasma activation and consecutive selection of a treatment method for an effective antibacterial surface construction. Copyright © 2016 Elsevier B.V. All rights reserved.

Bioethanol production from recovered napier grass with heavy metals.

Science.gov (United States)

Ko, Chun-Han; Yu, Fan-Chun; Chang, Fang-Chih; Yang, Bing-Yuan; Chen, Wen-Hua; Hwang, Wen-Song; Tu, Ta-Chih

2017-12-01

Using plants to absorb and accumulate heavy metals from polluted soil, followed by the recycling of explants containing heavy metals, can help achieve the goal of reverting contaminated soil to low heavy-metal content soil. However, the re-use of recovered explants can also be problematic. Meanwhile, bioethanol has become a popular energy source. In this study, napier grass was used for the remediation of soil contaminated with heavy metals (artificially contaminated soil). The influence of bioethanol production from napier grass after phytoremediation was also investigated. The concentration of Zn, Cd, and Cr in the contaminated soil was 1000, 100, and 250 mg/kg, respectively. After napier grass phytoremediation, the concentration (dry biomass) of Zn, Cd, and Cr in the explants was 2701.97 ± 173.49, 6.1 ± 2.3, and 74.24 ± 1.42 mg/kg, respectively. Biomass production in the unpolluted soil was 861.13 ± 4.23 g. The biomass production ratio in high Zn-polluted soil was only 3.89%, while it was 4.68% for Cd and 21.4% for Cr. The biomass obtained after napier grass phytoremediation was pretreated using the steam explosion conditions of 180 °C, for 10 min, with 1.5% H 2 SO 2 , followed by enzymatic hydrolysis. The efficiency of enzymatic hydrolysis for Zn-polluted biomass was 90% of the unpolluted biomass, while it was 77% for Cd, and approximately the same for Cr. The fermentation efficiency of the heavy-metal-containing biomass was higher than the control biomass. The fermentation ethanol concentration obtained was 8.69-12.68, 13.03-15.50, and 18.48-19.31 g/L in Zn, Cd, and Cr environments, respectively. Results show that the heavy metals had a positive effect on bacteria fermentation. However, the fermentation efficiency was lower for biomass with severe heavy metal pollution. Thus, the utilization of napier grass phytoremediation for bioethanol production has a positive effect on the sustainability of environmental resources. Copyright © 2017

Breeder reactor fuel fabrication system development

International Nuclear Information System (INIS)

Bennett, D.W.; Fritz, R.L.; McLemore, D.R.; Yatabe, J.M.

1981-01-01

Significant progress has been made in the design and development of remotely operated breeder reactor fuel fabrication and support systems (e.g., analytical chemistry). These activities are focused by the Secure Automated Fabrication (SAF) Program sponsored by the Department of Energy to provide: a reliable supply of fuel pins to support US liquid metal cooled breeder reactors and at the same time demonstrate the fabrication of mixed uranium/plutonium fuel by remotely operated and automated methods

A Comparison of Biocompatibility of a Titanium Alloy Fabricated by Electron Beam Melting and Selective Laser Melting.

Science.gov (United States)

Wang, Hong; Zhao, Bingjing; Liu, Changkui; Wang, Chao; Tan, Xinying; Hu, Min

2016-01-01

Electron beam melting (EBM) and selective laser melting (SLM) are two advanced rapid prototyping manufacturing technologies capable of fabricating complex structures and geometric shapes from metallic materials using computer tomography (CT) and Computer-aided Design (CAD) data. Compared to traditional technologies used for metallic products, EBM and SLM alter the mechanical, physical and chemical properties, which are closely related to the biocompatibility of metallic products. In this study, we evaluate and compare the biocompatibility, including cytocompatibility, haemocompatibility, skin irritation and skin sensitivity of Ti6Al4V fabricated by EBM and SLM. The results were analysed using one-way ANOVA and Tukey's multiple comparison test. Both the EBM and SLM Ti6Al4V exhibited good cytobiocompatibility. The haemolytic ratios of the SLM and EBM were 2.24% and 2.46%, respectively, which demonstrated good haemocompatibility. The EBM and SLM Ti6Al4V samples showed no dermal irritation when exposed to rabbits. In a delayed hypersensitivity test, no skin allergic reaction from the EBM or the SLM Ti6Al4V was observed in guinea pigs. Based on these results, Ti6Al4V fabricated by EBM and SLM were good cytobiocompatible, haemocompatible, non-irritant and non-sensitizing materials. Although the data for cell adhesion, proliferation, ALP activity and the haemolytic ratio was higher for the SLM group, there were no significant differences between the different manufacturing methods.

Silicone nanocomposite coatings for fabrics

Science.gov (United States)

Eberts, Kenneth (Inventor); Lee, Stein S. (Inventor); Singhal, Amit (Inventor); Ou, Runqing (Inventor)

2011-01-01

A silicone based coating for fabrics utilizing dual nanocomposite fillers providing enhanced mechanical and thermal properties to the silicone base. The first filler includes nanoclusters of polydimethylsiloxane (PDMS) and a metal oxide and a second filler of exfoliated clay nanoparticles. The coating is particularly suitable for inflatable fabrics used in several space, military, and consumer applications, including airbags, parachutes, rafts, boat sails, and inflatable shelters.

Process for production of a metal hydride

Science.gov (United States)

Allen, Nathan Tait; Butterick, III, Robert; Chin, Arthur Achhing; Millar, Dean Michael; Molzahn, David Craig

2014-08-12

A process for production of a metal hydride compound MH.sub.x, wherein x is one or two and M is an alkali metal, Be or Mg. The process comprises combining a compound of formula (R.sup.1O).sub.xM with aluminum, hydrogen and at least one metal selected from among titanium, zirconium, hafnium, niobium, vanadium, tantalum and iron to produce a compound of formula MH.sub.x. R.sup.1 is phenyl or phenyl substituted by at least one alkyl or alkoxy group. A mole ratio of aluminum to (R.sup.1O).sub.xM is from 0.1:1 to 1:1. The catalyst is present at a level of at least 200 ppm based on weight of aluminum.

Soft liquid phase adsorption for fabrication of organic semiconductor films on wettability patterned surfaces.

Science.gov (United States)

Watanabe, Satoshi; Akiyoshi, Yuri; Matsumoto, Mutsuyoshi

2014-01-01

We report a soft liquid-phase adsorption (SLPA) technique for the fabrication of organic semiconductor films on wettability-patterned substrates using toluene/water emulsions. Wettability-patterned substrates were obtained by the UV-ozone treatment of self-assembled monolayers of silane coupling agents on glass plates using a metal mask. Organic semiconductor polymer films were formed selectively on the hydrophobic part of the wettability-patterned substrates. The thickness of the films fabricated by the SLPA technique is significantly larger than that of the films fabricated by dip-coating and spin-coating techniques. The film thickness can be controlled by adjusting the volume ratio of toluene to water, immersion angle, immersion temperature, and immersion time. The SLPA technique allows for the direct production of organic semiconductor films on wettability-patterned substrates with minimized material consumption and reduced number of fabrication steps.

Fabrication and characterisation of ligand-functionalised ultrapure monodispersed metal nanoparticle nanoassemblies employing advanced gas deposition technique

Science.gov (United States)

Geremariam Welearegay, Tesfalem; Cindemir, Umut; Österlund, Lars; Ionescu, Radu

2018-02-01

Here, we report for the first time the fabrication of ligand-functionalised ultrapure monodispersed metal nanoparticles (Au, Cu, and Pt) from their pure metal precursors using the advanced gas deposition technique. The experimental conditions during nanoparticle formation were adjusted in order to obtain ultrafine isolated nanoparticles on different substrates. The morphology and surface analysis of the as-deposited metal nanoparticles were investigated using scanning electron microscopy, x-ray diffraction and Fourier transform infra-red spectroscopy, which demonstrated the formation of highly ordered pure crystalline nanoparticles with a relatively uniform size distribution of ∼10 nm (Au), ∼4 nm (Cu) and ∼3 nm (Pt), respectively. A broad range of organic ligands containing thiol or amine functional groups were attached to the nanoparticles to form continuous networks of nanoparticle-ligand nanoassemblies, which were characterised by scanning electron microscopy and x-ray photoelectron spectroscopy. The electrical resistance of the functional nanoassemblies deposited in the gap spacing of two microfabricated parallel Au electrodes patterned on silicon substrates ranged between tens of kΩ and tens of MΩ, which is suitable for use in many applications including (bio)chemical sensors, surface-enhanced Raman spectroscopy and molecular electronic rectifiers.

Optimization of Additive-Powder Characteristics for Metallic Micro-Cell UO{sub 2} Fuel Pellet Fabrication

Energy Technology Data Exchange (ETDEWEB)

Kim, Dong-Joo; Kim, Keon Sik; Rhee, Young Woo; Kim, Jong Hun; Oh, Jang Soo; Yang, Jae Ho; Koo, Yang-Hyun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2015-05-15

The improvement in the thermal conductivity of the UO{sub 2} fuel pellet can enhance the fuel performance in various aspects. The mobility of the fission gases is reduced by the lower temperature gradient in the UO{sub 2} fuel pellet. That is to say, the capability of the fission gas retention of the fuel pellet can increase. In addition, the lower centerline temperature of the fuel pellet affects the accident tolerance for nuclear fuel as well as the enhancement of fuel safety and fuel pellet integrity under normal operation conditions. The nuclear reactor power can be uprated owing to the higher safety margin. Thus, many researches on enhancing the thermal conductivity of a nuclear fuel pellet for LWRs have been performed. Typically, an enhancement of the thermal conductivity of the UO{sub 2} fuel pellet can be obtained by the addition of a higher thermal conductive material in the fuel pellet. To maximize the effect of the thermal conductivity enhancement, a continuous and uniform channel of the thermal conductive material in the UO{sub 2} matrix must be formed. To enhance the thermal conductivity of a UO{sub 2} fuel pellet, the development of fabrication process of a Cr metallic micro-cell UO{sub 2} pellet with a continuous and uniform channel of the Cr metallic phase was carried out. The formation of the Cr-oxide phases was prevented and the uniformity of the Cr-metal phase distribution was enhanced simultaneously, through the optimization of the additive-powder characteristics. In the results, the Cr metallic micro-cell pellet with continuous and uniform Cr metallic channel could be obtained.

Metal deposition by electroless plating on polydopamine functionalized micro- and nanoparticles.

Science.gov (United States)

Mondin, Giovanni; Wisser, Florian M; Leifert, Annika; Mohamed-Noriega, Nasser; Grothe, Julia; Dörfler, Susanne; Kaskel, Stefan

2013-12-01

A novel approach for the fabrication of metal coated micro- and nanoparticles by functionalization with a thin polydopamine layer followed by electroless plating is reported. The particles are initially coated with polydopamine via self-polymerization. The resulting polydopamine coated particles have a surface rich in catechols and amino groups, resulting in a high affinity toward metal ions. Thus, they provide an effective platform for selective electroless metal deposition without further activation and sensitization steps. The combination of a polydopamine-based functionalization with electroless plating ensures a simple, scalable, and cost-effective metal coating strategy. Silver-plated tungsten carbide microparticles, copper-plated tungsten carbide microparticles, and copper-plated alumina nanoparticles were successfully fabricated, showing also the high versatility of the method, since the polymerization of dopamine leads to the formation of an adherent polydopamine layer on the surface of particles of any material and size. The metal coated particles produced with this process are particularly well suited for the production of metal matrix composites, since the metal coating increases the wettability of the particles by the metal, promoting their integration within the matrix. Such composite materials are used in a variety of applications including electrical contacts, components for the automotive industries, magnets, and electromagnetic interference shielding. Copyright © 2013 Elsevier Inc. All rights reserved.

Metallic DFB lasers

NARCIS (Netherlands)

Marell, M.J.H.; Nötzel, R.; Smit, M.K.; Hill, M.T.; Pozo, J.; Mortensen, M.; Urbach, P.; Leijtens, X.; Yousefi, M.

2010-01-01

In this paper we present our latest results on the design, fabrication and characterization of metal coated DFB lasers. These devices are based on a specialform of the metal-insulator-metal waveguides, which support plasmon gap modes. The distributed feedback provides control over the laser ~

Immobilizer-assisted management of metal-contaminated agricultural soils for safer food production.

Science.gov (United States)

Kim, Kwon-Rae; Kim, Jeong-Gyu; Park, Jeong-Sik; Kim, Min-Suk; Owens, Gary; Youn, Gyu-Hoon; Lee, Jin-Su

2012-07-15

Production of food crops on metal contaminated agricultural soils is of concern because consumers are potentially exposed to hazardous metals via dietary intake of such crops or crop derived products. Therefore, the current study was conducted to develop management protocols for crop cultivation to allow safer food production. Metal uptake, as influenced by pH change-induced immobilizing agents (dolomite, steel slag, and agricultural lime) and sorption agents (zeolite and compost), was monitored in three common plants representative of leafy (Chinese cabbage), root (spring onion) and fruit (red pepper) vegetables, in a field experiment. The efficiency of the immobilizing agents was assessed by their ability to decrease the phytoavailability of metals (Cd, Pb, and Zn). The fruit vegetable (red pepper) showed the least accumulation of Cd (0.16-0.29 mgkg(-1) DW) and Pb (0.2-0.9 mgkg(-1) DW) in edible parts regardless of treatment, indicating selection of low metal accumulating crops was a reasonable strategy for safer food production. However, safer food production was more likely to be achievable by combining crop selection with immobilizing agent amendment of soils. Among the immobilizing agents, pH change-induced immobilizers were more effective than sorption agents, showing decreases in Cd and Pb concentrations in each plant well below standard limits. The efficiency of pH change-induced immobilizers was also comparable to reductions obtained by 'clean soil cover' where the total metal concentrations of the plow layer was reduced via capping the surface with uncontaminated soil, implying that pH change-induced immobilizers can be practically applied to metal contaminated agricultural soils for safer food production. Copyright © 2012 Elsevier Ltd. All rights reserved.

European Metals Conference

CERN Document Server

Vereecken, Jean

1991-01-01

This volume contains the papers that will be presented at 'EMC '91 '-the European Metals Conference-to be held in Brussels, Belgium, from 15 to 20 September 1991, and organized by Benelux Metallurgie, GDMB (Gesellschaft Deutscher Metallhutten­ und Bergleute) and IMM (the Institution of Mining and Metallurgy). 'EMC '91' is the first of an intended major series organized at the European level with the aim of bringing together all those who are involved with the extraction and processing of non-ferrous metals-European metallurgists and their international colleagues-to provide them with the opportunity to exchange views on the state and evolution of their industry. The programme covers all the different aspects of the metallurgy of non-ferrous metals from mining to fabricated products. Particular attention is being paid to the European non -ferrous industry with respect to changes in demand, the technology used, pressures on the environment and the competitive position of manufacturers. The contributions of the...

Chemical Separation of Fission Products in Uranium Metal Ingots from Electrolytic Reduction Process

International Nuclear Information System (INIS)

Lee, Chang-Heon; Kim, Min-Jae; Choi, Kwang-Soon; Jee, Kwang-Yong; Kim, Won-Ho

2006-01-01

Chemical characterization of various process materials is required for the optimization of the electrolytic reduction process in which uranium dioxide, a matrix of spent PWR fuels, is electrolytically reduced to uranium metal in a medium of LiCl-Li 2 O molten at 650 .deg. C. In the uranium metal ingots of interest in this study, residual process materials and corrosion products as well as fission products are involved to some extent, which further adds difficulties to the determination of trace fission products. Besides it, direct inductively coupled plasma atomic emission spectrometric (ICP-AES) analysis of uranium bearing materials such as the uranium metal ingots is not possible because a severe spectral interference is found in the intensely complex atomic emission spectra of uranium. Thus an adequate separation procedure for the fission products should be employed prior to their determinations. In present study ion exchange and extraction chromatographic methods were adopted for selective separation of the fission products from residual process materials, corrosion products and uranium matrix. The sorption behaviour of anion and tri-nbutylphosphate (TBP) extraction chromatographic resins for the metals in acidic solutions simulated for the uranium metal ingot solutions was investigated. Then the validity of the separation procedure for its reliability and applicability was evaluated by measuring recoveries of the metals added

A study on compound contents for plastic injection molding products of metallic resin pigment

International Nuclear Information System (INIS)

Park, Young Whan; Kwak, Jae Seob; Lee, Gyu Sang

2016-01-01

Injection molding process is widely used for producing most plastic products. In order to make a metal-colored plastic product especially in modern luxury home alliances, metallic pigments which are mixed to a basic resin material for injection molding are available. However, the process control for the metal-colored plastic product is extremely difficult due to non-uniform melt flow of the metallic resin pigments. To improve the process efficiency, a rapid mold cooling method by a compressed cryogenic fluid and electricity mold are also proposed to decrease undesired compound contents within a molded plastic product. In this study, a quality of the metal-colored plastic product is evaluated with process parameters; injection speed, injection pressure, and pigment contents, and an influence of the rapid cooling and heating system is demonstrated

A study on compound contents for plastic injection molding products of metallic resin pigment

Energy Technology Data Exchange (ETDEWEB)

Park, Young Whan; Kwak, Jae Seob [Dept. of Mechanical Engineering, Pukyong National University, Busan (Korea, Republic of); Lee, Gyu Sang [Alliance Molding Engineering TeamLG Electronics Inc., Osan (Korea, Republic of)

2016-12-15

Injection molding process is widely used for producing most plastic products. In order to make a metal-colored plastic product especially in modern luxury home alliances, metallic pigments which are mixed to a basic resin material for injection molding are available. However, the process control for the metal-colored plastic product is extremely difficult due to non-uniform melt flow of the metallic resin pigments. To improve the process efficiency, a rapid mold cooling method by a compressed cryogenic fluid and electricity mold are also proposed to decrease undesired compound contents within a molded plastic product. In this study, a quality of the metal-colored plastic product is evaluated with process parameters; injection speed, injection pressure, and pigment contents, and an influence of the rapid cooling and heating system is demonstrated.

Three techniques for the fabrication of high precision, mm-sized metal components based on two-photon lithography, applied for manufacturing horn antennas for THz transceivers

Science.gov (United States)

Standaert, Alexander; Brancato, Luigi; Lips, Bram; Ceyssens, Frederik; Puers, Robert; Reynaert, Patrick

2018-03-01

This paper proposes a novel packaging solution which integrates micro-machined 3D horn antennas with millimeter-wave and THz tranceivers. This packaging solution is shown to be a valid competitor to existing technologies like metallic split-block waveguides and low temperature cofired ceramics. Three different fabrication methods based on two-photon lithography are presented to form the horn antennas. The first uses two-photon lithography to form the bulk of the antenna. This structure is then metalised through physical vapor deposition (PVD) and copper plating. The second fabrication method makes use of a soft polydimethylsiloxane (PDMS) mold to easily replicate structures and the third method forms the horn antenna through electroforming. A prototype is accurately positioned on top of a 400 GHz 28 nm CMOS transmitter and glued in place with epoxy, thus providing a fully packaged solution. Measurement results show a 12 dB increase in the antenna gain when using the packaged solution. The fabrication processes are not limited to horn antennas alone and can be used to form a wide range of mm-sized metal components.

Fabrication of high precision metallic freeform mirrors with magnetorheological finishing (MRF)

Science.gov (United States)

Beier, Matthias; Scheiding, Sebastian; Gebhardt, Andreas; Loose, Roman; Risse, Stefan; Eberhardt, Ramona; Tünnermann, Andreas

2013-09-01

The fabrication of complex shaped metal mirrors for optical imaging is a classical application area of diamond machining techniques. Aspherical and freeform shaped optical components up to several 100 mm in diameter can be manufactured with high precision in an acceptable amount of time. However, applications are naturally limited to the infrared spectral region due to scatter losses for shorter wavelengths as a result of the remaining periodic diamond turning structure. Achieving diffraction limited performance in the visible spectrum demands for the application of additional polishing steps. Magnetorheological Finishing (MRF) is a powerful tool to improve figure and finish of complex shaped optics at the same time in a single processing step. The application of MRF as a figuring tool for precise metal mirrors is a nontrivial task since the technology was primarily developed for figuring and finishing a variety of other optical materials, such as glasses or glass ceramics. In the presented work, MRF is used as a figuring tool for diamond turned aluminum lightweight mirrors with electroless nickel plating. It is applied as a direct follow-up process after diamond machining of the mirrors. A high precision measurement setup, composed of an interferometer and an advanced Computer Generated Hologram with additional alignment features, allows for precise metrology of the freeform shaped optics in short measuring cycles. Shape deviations less than 150 nm PV / 20 nm rms are achieved reliably for freeform mirrors with apertures of more than 300 mm. Characterization of removable and induced spatial frequencies is carried out by investigating the Power Spectral Density.

Micromechanical Structures Fabrication; FINAL

International Nuclear Information System (INIS)

Rajic, S

2001-01-01

Work in materials other than silicon for MEMS applications has typically been restricted to metals and metal oxides instead of more ''exotic'' semiconductors. However, group III-V and II-VI semiconductors form a very important and versatile collection of material and electronic parameters available to the MEMS and MOEMS designer. With these materials, not only are the traditional mechanical material variables (thermal conductivity, thermal expansion, Young's modulus, etc.) available, but also chemical constituents can be varied in ternary and quaternary materials. This flexibility can be extremely important for both friction and chemical compatibility issues for MEMS. In addition, the ability to continually vary the bandgap energy can be particularly useful for many electronics and infrared detection applications. However, there are two major obstacles associated with alternate semiconductor material MEMS. The first issue is the actual fabrication of non-silicon micro-devices and the second impediment is communicating with these novel devices. We have implemented an essentially material independent fabrication method that is amenable to most group III-V and II-VI semiconductors. This technique uses a combination of non-traditional direct write precision fabrication processes such as diamond turning, ion milling, laser ablation, etc. This type of deterministic fabrication approach lends itself to an almost trivial assembly process. We also implemented a mechanical, electrical, and optical self-aligning hybridization technique for these alternate-material MEMS substrates

The computer-aided design of rubber-metal products

Directory of Open Access Journals (Sweden)

Pavlo S. Shvets

2015-12-01

Full Text Available The important problem in design of rubber-metal products is the optimization of their mass without sacrificing of proportionality factor is in the limits of standard. Aim: The aim of this work is to improve the computer-aided systems by development and implementation of improved optimization method in rubber-metal CAD systems for designers based on the reverse optimization. Materials and Methods: The paper studies the matters of computer-aided structural design of technical composite products composed of anisotropic materials that are essentially different in properties. Results: The structure of CAD systems for designers solving the problems of such design is offered and the work principles of its subsystems are described. It is shown that complicated systems optimization in CAD systems must consider as restrictions the entitative connection between separate elements of these systems within the area of the optimizing arguments. Conclusions: The problem of the “reverse” optimization when objective functions are the connectivity area parameters is considered. In many cases, this allows receiving solutions that are more effective during the computer-aided design process. The developed CAD system for designers was used during the production of rubber-metal shock absorbers at the Odessa Rubber Technical Articles Plant. The positive technical and economic effect was obtained.

Fabrication of ruthenium metal nanosheets via topotactic metallization of exfoliated ruthenate nanosheets.

Science.gov (United States)

Fukuda, Katsutoshi; Sato, Jun; Saida, Takahiro; Sugimoto, Wataru; Ebina, Yasuo; Shibata, Tatsuo; Osada, Minoru; Sasaki, Takayoshi

2013-03-04

The metallization behavior of molecularly thin RuO2 nanosheets obtained from complete delamination of layered ruthenates was studied. Interestingly, the RuO2 nanosheets in a monolayer state topotactically transformed into a single layer of Ru atoms, i.e., ruthenium metal nanosheets, which can be regarded as a new family of nanosized metals.

Fabrication of smooth patterned structures of refractory metals, semiconductors, and oxides via template stripping.

Science.gov (United States)

Park, Jong Hyuk; Nagpal, Prashant; McPeak, Kevin M; Lindquist, Nathan C; Oh, Sang-Hyun; Norris, David J

2013-10-09

The template-stripping method can yield smooth patterned films without surface contamination. However, the process is typically limited to coinage metals such as silver and gold because other materials cannot be readily stripped from silicon templates due to strong adhesion. Herein, we report a more general template-stripping method that is applicable to a larger variety of materials, including refractory metals, semiconductors, and oxides. To address the adhesion issue, we introduce a thin gold layer between the template and the deposited materials. After peeling off the combined film from the template, the gold layer can be selectively removed via wet etching to reveal a smooth patterned structure of the desired material. Further, we demonstrate template-stripped multilayer structures that have potential applications for photovoltaics and solar absorbers. An entire patterned device, which can include a transparent conductor, semiconductor absorber, and back contact, can be fabricated. Since our approach can also produce many copies of the patterned structure with high fidelity by reusing the template, a low-cost and high-throughput process in micro- and nanofabrication is provided that is useful for electronics, plasmonics, and nanophotonics.

Topological superconductivity in metallic nanowires fabricated with a scanning tunneling microscope

International Nuclear Information System (INIS)

Rodrigo, J G; Crespo, V; Suderow, H; Vieira, S; Guinea, F

2013-01-01

We report on several low-temperature experiments supporting the presence of Majorana fermions in superconducting lead nanowires fabricated with a scanning tunneling microscope (STM). These nanowires are the connecting bridges between the STM tip and the sample resulting from indentation–retraction processes. We show here that by a controlled tuning of the nanowire region, in which superconductivity is confined by applied magnetic fields, the conductance curves obtained in these situations are indicative of topological superconductivity and Majorana fermions. The most prominent feature of this behavior is the emergence of a zero bias peak in the conductance curves, superimposed on a background characteristic of the conductance between a normal metal and a superconductor in the Andreev regime. The zero bias peak emerges in some nanowires when a magnetic field larger than the lead bulk critical field is applied. This field drives one of the electrodes into the normal state while the other, the tip, remains superconducting on its apex. Meanwhile a topological superconducting state appears in the connecting nanowire of nanometric size. (paper)

Thermodynamic evaluation of highly exothermic reactions for the fabrication of ceramic metal composites

International Nuclear Information System (INIS)

Rodrigues, J.A.; Pandolfelli, V.C.; Botta Filho, W.J.; Tomasi, R.; Stevens, R.; Brook, R.J.

1990-01-01

Highly exothermic reactions allow the synthesis or production of materials. Which present advantages regarding to energy saving, simplicity of process and higher purity of the products. Considering adiabatic conditions these reactions give off a large amount of heat which will raise the temperature of the system, allowing the production of highly refractory materials. This paper presents a thermodynamic forecast of reactants are Nb2O5, Al e Zr. The objective is to produce high toughness alumina matrix composites containing ZrO2 particles and Nb metal. (author)

Investigation of cadmium pollution in the spruce saplings near the metal production factory.

Science.gov (United States)

Hashemi, Seyed Armin; Farajpour, Ghasem

2016-02-01

Toxic metals such as lead and cadmium are among the pollutants that are created by the metal production factories and disseminated in the nature. In order to study the quantity of cadmium pollution in the environment of the metal production factories, 50 saplings of the spruce species at the peripheries of the metal production factories were examined and the samples of the leaves, roots, and stems of saplings planted around the factory and the soil of the environment of the factory were studied to investigate pollution with cadmium. They were compared to the soil and saplings of the spruce trees planted outside the factory as observer region. The results showed that the quantity of pollution in the leaves, stems, and roots of the trees planted inside the factory environment were estimated at 1.1, 1.5, and 2.5 mg/kg, respectively, and this indicated a significant difference with the observer region (p metal production factory was estimated at 6.8 mg/kg in the depth of 0-10 cm beneath the level of the soil. The length of roots in the saplings planted around the factory of metal production stood at 11 and 14.5 cm in the observer region which had a significant difference with the observer region (p production processes in the factory. © The Author(s) 2013.

A novel coping metal material CoCrCu alloy fabricated by selective laser melting with antimicrobial and antibiofilm properties.

Science.gov (United States)

Ren, Ling; Memarzadeh, Kaveh; Zhang, Shuyuan; Sun, Ziqing; Yang, Chunguang; Ren, Guogang; Allaker, Robert P; Yang, Ke

2016-10-01

The aim of this study was to fabricate a novel coping metal CoCrCu alloy using a selective laser melting (SLM) technique with antimicrobial and antibiofilm activities and to investigate its microstructure, mechanical properties, corrosion resistance and biocompatibility. Novel CoCrCu alloy was fabricated using SLM from a mixture of commercial CoCr based alloy and elemental Cu powders. SLM CoCr without Cu served as control. Antibacterial activity was analyzed using standard antimicrobial tests, and antibiofilm properties were investigated using confocal laser scanning microscope. Cu distribution and microstructure were determined using scanning electron microscope, optical microscopy and X-ray diffraction. Corrosion resistance was evaluated by potential dynamic polarization and biocompatibility measured using an MTT assay. SLM CoCrCu alloys were found to be bactericidal and able to inhibit biofilm formation. Other factors such as microstructure, mechanical properties, corrosion resistance and biocompatibility were similar to those of SLM CoCr alloys. The addition of appropriate amounts of Cu not only maintains normal beneficial properties of CoCr based alloys, but also provides SLM CoCrCu alloys with excellent antibacterial and antibiofilm capabilities. This material has the potential to be used as a coping metal for dental applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Biogas production as affected by heavy metals in the anaerobic digestion of sludge

Directory of Open Access Journals (Sweden)

Hussein I. Abdel-Shafy

2014-12-01

The sewage sludge samples were separated from the sewage water of the pilot plant at the National Research Centre, TDC site. The effect of heavy metals on the biogas production of the anaerobic digester was studied. The inhibitory effect on the biogas production and toxic level of metals was determined in this study. The general ranking of heavy metal toxicity appears to be Hg > Cd > Cr (III. The present investigation reveals that heavy metals in addition to the anaerobic digester decreased the biogas production as an indication of efficiency of the process. A significant decrease in gas production and volatile organic matter removal was obtained. It was also noted that an accumulation of organic acid intermediates was obtained as a result of methanogenic bacterial inhibition. This accumulation was limited during the pulse feed of metals. This is due to the rapid poisoning of the active bacterial forms in the digester.

Fabrication of off-axis parabolic mirrors

International Nuclear Information System (INIS)

Bezik, M.J.; Gerth, H.L.; Sladky, R.E.; Washington, C.A.

1978-08-01

The report describes the fabrication process, including metal preparation, copper electroplating, single-crystal-diamond turning, optical inspection, and polishing, used to manufacture the focusing mirrors for the 10-kJ laser fusion experiment being conducted by the Los Alamos Scientific Laboratory. Fabrication of these mirrors by the techniques described resulted in diffraction-limited optics at a 10.6 μm wavelength

Microbial and heavy metal contamination of pineapple products ...

African Journals Online (AJOL)

SAM

Quantitative determination of heavy metals: zinc, iron, lead, copper, cadmium and aluminium ...... consumption of dairy products, fish/seafood and meat from Ismailia ... Contamination in Green Leafy Vegetables Grown in Bangalore Urban.

Design and fabrication of zeolite macro- and micromembranes

Science.gov (United States)

Chau, Lik Hang Joseph

2001-07-01

The chemical nature of the support surface influences zeolite nucleation, crystal growth and elm adhesion. It had been demonstrated that chemical modification of support surface can significantly alter the zeolite film and has a good potential for large-scale applications for zeolite membrane production. The incorporation of titanium and vanadium metal ions into the structural framework of MFI zeolite imparts the material with catalytic properties. The effects of silica and metal (i.e., Ti and V) content, template concentration and temperature on the zeolite membrane growth and morphology were investigated. Single-gas permeation experiments were conducted for noble gases (He and Ar), inorganic gases (H2, N2, SF6) and hydrocarbons (methane, n-C4, i-C4) to determine the separation performance of these membranes. Using a new fabrication method based on microelectronic fabrication and zeolite thin film technologies, complex microchannel geometry and network (supported zeolite films. The zeolite micropatterns were stable even after repeated thermal cycling between 303 K and 873 K for prolonged periods of time. This work also demonstrates that zeolites (i.e., Sil-1, ZSM-5 and TS-1) can be employed as catalyst, membrane or structural materials in miniature chemical devices. Traditional semiconductor fabrication technology was employed in micromachining the device architecture. Four strategies for the manufacture of zeolite catalytic microreactors were discussed: zeolite powder coating, uniform zeolite film growth, localized zeolite growth, and etching of zeolite-silicon composite film growth inhibitors. Silicalite-1 was also prepared as free-standing membrane for zeolite membrane microseparators.

Low-cost zinc-plated photoanode for fabric-type dye-sensitized solar cells

Energy Technology Data Exchange (ETDEWEB)

Kong, Lingfeng; Bao, Yunna; Guo, Wanwan; Cheng, Li; Du, Jun; Liu, Renlong [College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400030 (China); Wang, Yundong [Department of Chemical Engineering, Tsinghua University, State Key Lab of Chemical Engineering, Beijing 100084 (China); Fan, Xing, E-mail: foxcqdx@cqu.edu.cn [College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400030 (China); Tao, Changyuan [College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400030 (China)

2016-02-15

Graphical abstract: - Highlights: • Fabric-type flexible solar cells have been assembled on Zn-plated wires and meshes. • Metal Zn can improve the carriers transfer over the metal/ZnO nanoarrays interface. • A current increase by ∼6 mA/cm{sup 2} was realized by plating Zn on various metal substrates. • All-solid fabric-type DSSC was also assembled on Zn-plated metal wires. - Abstract: Fabric-type flexible solar cells have been recently proposed as a very promising power source for wearable electronics. To increase the photocurrent of fabric-type flexible solar cells, low-cost zinc-plated wire and mesh photoanodes are assembled for the first time through a mild wet process. Given the protection of the compact protection layer, the DSSC device could benefit from the low work function of Zn and self-repairing behavior on the Zn/ZnO interface. An evident current increase by ∼6 mA/cm{sup 2} could be observed after coating a layer of metal Zn on various metal substrates, such as traditional stainless steel wire. Given the self-repairing behavior on Zn/ZnO interface, the Zn layer can help to improve the interfacial carrier transfer, leading to better photovoltaic performance, for both liquid-type and solid-type cells.

Low-cost zinc-plated photoanode for fabric-type dye-sensitized solar cells

International Nuclear Information System (INIS)

Kong, Lingfeng; Bao, Yunna; Guo, Wanwan; Cheng, Li; Du, Jun; Liu, Renlong; Wang, Yundong; Fan, Xing; Tao, Changyuan

2016-01-01

Graphical abstract: - Highlights: • Fabric-type flexible solar cells have been assembled on Zn-plated wires and meshes. • Metal Zn can improve the carriers transfer over the metal/ZnO nanoarrays interface. • A current increase by ∼6 mA/cm"2 was realized by plating Zn on various metal substrates. • All-solid fabric-type DSSC was also assembled on Zn-plated metal wires. - Abstract: Fabric-type flexible solar cells have been recently proposed as a very promising power source for wearable electronics. To increase the photocurrent of fabric-type flexible solar cells, low-cost zinc-plated wire and mesh photoanodes are assembled for the first time through a mild wet process. Given the protection of the compact protection layer, the DSSC device could benefit from the low work function of Zn and self-repairing behavior on the Zn/ZnO interface. An evident current increase by ∼6 mA/cm"2 could be observed after coating a layer of metal Zn on various metal substrates, such as traditional stainless steel wire. Given the self-repairing behavior on Zn/ZnO interface, the Zn layer can help to improve the interfacial carrier transfer, leading to better photovoltaic performance, for both liquid-type and solid-type cells.

Fabrication of Hierarchically Micro- and Nano-structured Mold Surfaces Using Laser Ablation for Mass Production of Superhydrophobic Surfaces

Science.gov (United States)

Noh, Jiwhan; Lee, Jae-Hoon; Na, Suckjoo; Lim, Hyuneui; Jung, Dae-Hwan

2010-10-01

Many studies have examined the formation of surfaces with mixed patterns of micro- and nano-sized lotus leaves that have hydrophobic properties. In this study, micro- and nano-shapes such as lotus leaves were fabricated on a metal mold surface using laser ablation and ripple formation. A microstructure on the mold surface was replicated onto poly(dimethylsiloxane) (PDMS) using the polymer casting method to manufacture low-cost hydrophobic surfaces. A PDMS surface with micro- and nano-structures that were the inverse image of a lotus leaf showed hydrophobic characteristics (water contact angle: 157°). From these results, we deduced that portions of the microstructures were wet and that air gaps existed between the microstructures and the water drops. In this paper we suggest the possibility of the mass production of hydrophobic plastic surfaces and the development of a methodology for the hydrophobic texturing of various polymer surfaces, using the polymer casting method with laser-processed molds.

Advances in Metallic Fuels for High Burnup and Actinide Transmutation

Energy Technology Data Exchange (ETDEWEB)

Hayes, S. L.; Harp, J. M.; Chichester, H. J. M.; Fielding, R. S.; Mariani, R. D.; Carmack, W. J.

2016-10-01

Research and development activities on metallic fuels in the US are focused on their potential use for actinide transmutation in future sodium fast reactors. As part of this application, there is a desire to demonstrate a multifold increase in burnup potential. A number of metallic fuel design innovations are under investigation with a view toward significantly increasing the burnup potential of metallic fuels, since higher discharge burnups equate to lower potential actinide losses during recycle. Promising innovations under investigation include: 1) lowering the fuel smeared density in order to accommodate the additional swelling expected as burnups increase, 2) utilizing an annular fuel geometry for better geometrical stability at low smeared densities, as well as the potential to eliminate the need for a sodium bond, and 3) minor alloy additions to immobilize lanthanide fission products inside the metallic fuel matrix and prevent their transport to the cladding resulting in fuel-cladding chemical interaction. This paper presents results from these efforts to advance metallic fuel technology in support of high burnup and actinide transmutation objectives. Highlights include examples of fabrication of low smeared density annular metallic fuels, experiments to identify alloy additions effective in immobilizing lanthanide fission products, and early postirradiation examinations of annular metallic fuels having low smeared densities and palladium additions for fission product immobilization.

Fabrication of sealed radiation sources

International Nuclear Information System (INIS)

Mars, Jean.

1977-01-01

The description is given for fabricating a sealed radiation source, consisting in depositing on a metal substrate a thin active coat of a radioelement, termed first coat, submitting this coated substrate to an oxidation treatment in order to obtain on the first coat an inactive coat of an oxide of the metal, termed second coat, and depositing a coat of varnish on this second inactive coat [fr

Proposed industrial recovered materials utilization targets for the metals and metal products industry

Energy Technology Data Exchange (ETDEWEB)

None

1979-05-01

Set targets for increased utilization of energy-saving recovered materials in the metals and metal products industries (ferrous, aluminium, copper, zinc, and lead) are discussed. Data preparation and methodology development and analysis of the technological and economic factors in order to prepare draft targets for the use of recovered materials are covered. Chapter 2 provides an introductory discussion of the factors that affect the recovery and reuse of secondary materials and the competition between the primary and secondary metals industries. Chapter 3 presents general profiles for the major industrial segments comprising SIC 33, including industry structure, process technology, materials and recycling flow, and future trends for the 5 industries: ferrous, aluminium, copper, zinc, and lead. Chapter 4 presents the evaluation of recycling targets for those industries. (MCW)

A wearable 12-lead ECG acquisition system with fabric electrodes.

Science.gov (United States)

Haoshi Zhang; Lan Tian; Huiyang Lu; Ming Zhou; Haiqing Zou; Peng Fang; Fuan Yao; Guanglin Li

2017-07-01

Continuous electrocardiogram (ECG) monitoring is significant for prevention of heart disease and is becoming an important part of personal and family health care. In most of the existing wearable solutions, conventional metal sensors and corresponding chips are simply integrated into clothes and usually could only collect few leads of ECG signals that could not provide enough information for diagnosis of cardiac diseases such as arrhythmia and myocardial ischemia. In this study, a wearable 12-lead ECG acquisition system with fabric electrodes was developed and could simultaneously process 12 leads of ECG signals. By integrating the fabric electrodes into a T-shirt, the wearable system would provide a comfortable and convenient user interface for ECG recording. For comparison, the proposed fabric electrode and the gelled traditional metal electrodes were used to collect ECG signals on a subject, respectively. The approximate entropy (ApEn) of ECG signals from both types of electrodes were calculated. The experimental results show that the fabric electrodes could achieve similar performance as the gelled metal electrodes. This preliminary work has demonstrated that the developed ECG system with fabric electrodes could be utilized for wearable health management and telemedicine applications.

Fabricating plasmonic components for nanophotonics

DEFF Research Database (Denmark)

Boltasseva, Alexandra; Nielsen, Rasmus Bundgaard; Jeppesen, Claus

2009-01-01

We report on experimental realization of different metal-dielectric structures that are used as surface plasmon polariton waveguides and as plasmonic metamaterials. Fabrication approaches based on different lithographic and deposition techniques are discussed....

Analysis of roll-stamped light guide plate fabricated with laser-ablated stamper

Science.gov (United States)

Na, Hyunjun; Hong, Seokkwan; Kim, Jongsun; Hwang, Jeongho; Joo, Byungyun; Yoon, Kyunghwan; Kang, Jeongjin

2017-12-01

LGP (light guide plate) is one of the major components of LCD (liquid crystal display), and it makes surface illumination for LCD backlit. LGP is a transparent plastic plate usually produced by injection molding process. On the back of LGP there are micron size patterns for extraction of light. Recently a roll-stamping process has achieved the high mass productivity of thinner LGPs. In order to fabricate optical patterns on LGPs, a fabricating tool called as a stamper is used. Micro patterns on metallic stampers are made by several micro machining processes such as chemical etching, LIGA-reflow, and laser ablation. In this study, a roll-stamping process by using a laser ablated metallic stamper was dealt with in consideration of the compatibility with the roll-stamping process. LGP fabricating tests were performed using a roll-stamping process with four different roll pressures. Pattern shapes on the stamper fabricated by laser ablation and transcription ratios of the roll-stamping process were analyzed, and LGP luminance was evaluated. Based on the evaluation, optical simulation model for LGP was made and simulation accuracy was evaluated. Simulation results showed good agreements with optical performance of LGPs in the brightness and uniformity. It was also shown that the roll-stamped LGP has the possibility of better optical performance than the conventional injection molded LGP. It was also shown that the roll-stamped LGP with the laser ablated stamper is potential to have better optical performance than the conventional injection molded LGP.

Production of Liquid Metal Spheres by Molding

Directory of Open Access Journals (Sweden)

Mohammed G. Mohammed

2014-10-01

Full Text Available This paper demonstrates a molding technique for producing spheres composed of eutectic gallium-indium (EGaIn with diameters ranging from hundreds of microns to a couple millimeters. The technique starts by spreading EGaIn across an elastomeric sheet featuring cylindrical reservoirs defined by replica molding. The metal flows into these features during spreading. The spontaneous formation of a thin oxide layer on the liquid metal keeps the metal flush inside these reservoirs. Subsequent exposure to acid removes the oxide and causes the metal to bead up into a sphere with a size dictated by the volume of the reservoirs. This technique allows for the production and patterning of droplets with a wide range of volumes, from tens of nanoliters up to a few microliters. EGaIn spheres can be embedded or encased subsequently in polymer matrices using this technique. These spheres may be useful as solder bumps, electrodes, thermal contacts or components in microfluidic devices (valves, switches, pumps. The ease of parallel-processing and the ability to control the location of the droplets during their formation distinguishes this technique.

Development of the production of lead and precious metals in Central Asia

Directory of Open Access Journals (Sweden)

Nikolić Branislav

2014-01-01

Full Text Available There were several rich deposits of polymetal ores of non-ferrous and precious metals in the region of Imperial Russia and the Soviet Union. Metallurgical production of these metals was developed even a thousand years ago and was in the top of the world at the beginning of the fourth quarter of the twentieth century. The disintegration of the Soviet Union and the change of government structures caused a reduction of metallurgical production, but there are all conditions to intensify and increase the production of non-ferrous and precious metals in Russia and other former Soviet republics, which are now middle-asian countries.

A Review on Metal Nanoparticles Nucleation and Growth on/in Graphene

Directory of Open Access Journals (Sweden)

Francesco Ruffino

2017-07-01

Full Text Available In this review, the fundamental aspects (with particular focus to the microscopic thermodynamics and kinetics mechanisms concerning the fabrication of graphene-metal nanoparticles composites are discussed. In particular, the attention is devoted to those fabrication methods involving vapor-phase depositions of metals on/in graphene-based materials. Graphene-metal nanoparticles composites are, nowadays, widely investigated both from a basic scientific and from several technological point of views. In fact, these graphene-based systems present wide-range tunable and functional electrical, optical, and mechanical properties which can be exploited for the design and production of innovative and high-efficiency devices. This research field is, so, a wide and multidisciplinary section in the nanotechnology field of study. So, this review aims to discuss, in a synthetic and systematic framework, the basic microscopic mechanisms and processes involved in metal nanoparticles formation on graphene sheets by physical vapor deposition methods and on their evolution by post-deposition processes. This is made by putting at the basis of the discussions some specific examples to draw insights on the common general physical and chemical properties and parameters involved in the synergistic interaction processes between graphene and metals.

Metal spectra as indicators of development

Science.gov (United States)

Graedel, T. E.; Cao, J.

2010-01-01

We have assembled extensive information on the cycles of seven industrial metals in 49 countries, territories, or groups of countries, drawn from a database of some 200,000 material flows, and have devised analytical approaches to treat the suite of metals as composing an approach to a national “materials metabolism.” We demonstrate that in some of the more developed countries, per capita metal use is more than 10 times the global average. Additionally, countries that use more than the per capita world average of any metal do so for all metals, and vice versa, and countries that are above global average rates of use are very likely to be above global average rates at all stages of metal life cycles from fabrication onward. We show that all countries are strongly dependent on international trade to supply the spectrum of nonrenewable resources that modern technology requires, regardless of their level of development. We also find that the rate of use of the spectrum of metals stock is highly correlated to per capita gross domestic product, as well as to the Human Development Index and the Global Competitiveness Innovation Index. The implication is that as wealth and technology increase in developing countries, strong demand will be created not for a few key resources, but across the entire spectrum of the industrial metals. Long-term metal demand can be estimated given gross domestic product projections; the results suggest overall metal flow into use in 2050 of 5–10 times today’s level should supplies permit. PMID:21098309

Catalytic cracking of vegetable oil with metal oxides for biofuel production

International Nuclear Information System (INIS)

Yigezu, Zerihun Demrew; Muthukumar, Karuppan

2014-01-01

Highlights: • Biofuel was synthesized from vegetable oil by catalytic cracking. • Performance of six different metal catalysts was studied. • Influence of temperature and reaction time on the process was evaluated. • Methyl and ethyl esters are the major components of the biofuel synthesized. - Abstract: This study presents the utilization of metal oxides for the biofuel production from vegetable oil. The physical and chemical properties of the diesel-like products obtained, and the influence of reaction variables on the product distribution were investigated. Six different metal oxides (Co 3 O 4 , KOH, MoO 3 , NiO, V 2 O 5 , and ZnO) were employed as catalysts and the results indicated that the metal oxides are suitable for catalyzing the conversion of oil into organic liquid products (OLPs). The maximum conversion (87.6%) was obtained with V 2 O 5 at 320 °C in 40 min whereas a minimum conversion (55.1%) was obtained with MoO 3 at 390 °C in 30 min. The physical characteristics of the product obtained (density, specific gravity, higher heat value, flash point and kinematic viscosity), were in line with ASTM D6751 (B100) standards. The hydrocarbons majorly present in the product were found to be methyl and ethyl esters. Furthermore, OLPs obtained were distilled and separated into four components. The amount of light hydrocarbons, gasoline, kerosene and heavy oil like components obtained were 18.73%, 33.62%, 24.91% and 90.93%, respectively

Fabrication of transparent ceramics using nanoparticles

Science.gov (United States)

Cherepy, Nerine J; Tillotson, Thomas M; Kuntz, Joshua D; Payne, Stephen A

2012-09-18

A method of fabrication of a transparent ceramic using nanoparticles synthesized via organic acid complexation-combustion includes providing metal salts, dissolving said metal salts to produce an aqueous salt solution, adding an organic chelating agent to produce a complexed-metal sol, heating said complexed-metal sol to produce a gel, drying said gel to produce a powder, combusting said powder to produce nano-particles, calcining said nano-particles to produce oxide nano-particles, forming said oxide nano-particles into a green body, and sintering said green body to produce the transparent ceramic.

Ceramic nanostructures and methods of fabrication

Science.gov (United States)

Ripley, Edward B [Knoxville, TN; Seals, Roland D [Oak Ridge, TN; Morrell, Jonathan S [Knoxville, TN

2009-11-24

Structures and methods for the fabrication of ceramic nanostructures. Structures include metal particles, preferably comprising copper, disposed on a ceramic substrate. The structures are heated, preferably in the presence of microwaves, to a temperature that softens the metal particles and preferably forms a pool of molten ceramic under the softened metal particle. A nano-generator is created wherein ceramic material diffuses through the molten particle and forms ceramic nanostructures on a polar site of the metal particle. The nanostructures may comprise silica, alumina, titania, or compounds or mixtures thereof.

Surface area and chemical reactivity characteristics of uranium metal corrosion products

International Nuclear Information System (INIS)

Totemeier, T. C.

1998-01-01

The results of an initial characterization of hydride-containing corrosion products from uranium metal Zero Power Physics Reactor (ZPPR) fuel plates are presented. Sorption analyses using the BET method with a Kr adsorbate were performed to measure the specific areas of corrosion product samples. The specific surface areas of the corrosion products varied from 0.66 to 1.01 m 2 /g. The reactivity of the products in Ar-9%O 2 and Ar-20%O 2 were measured at temperatures between 35 C and 150 C using a thermo-gravimetric analyzer. Ignition of the products occurred at temperatures of 150 C and above. The oxidation rates below ignition were comparable to rates observed for uranium metal

Development of indigenous laboratory scale gas atomizer for producing metal powders

International Nuclear Information System (INIS)

Khan, K.K.; Qasim, A.M.; Ahmed, P.

2011-01-01

Gas atomization is one of the methods for production of clean metal powders at relatively moderate cost. A laboratory scale gas atomizer was designed and fabricated indigenously to produce metal powders with a batch capacity of 500 g of copper (Cu). The design includes several features regarding fabrication and operation to provide optimum conditions for atomization. The inner diameter of atomizing chamber is 440 mm and its height is 1200 mm. The atomizing nozzle is of annular confined convergent type with an angle of 25 degree. Argon gas at desired pressure has been used for atomizing the metals to produce relatively clean powders. A provision has also been made to view the atomization process. The indigenous laboratory scale gas atomizer was used to produce tin (Sn) and copper (Cu) powders with different atomizing gas pressures ranging from 2 to 10 bar. The particle size of different powders produced ranges from 40 to 400 im. (author)

In situ fabrication of electrochemically grown mesoporous metallic thin films by anodic dissolution in deep eutectic solvents.

Science.gov (United States)

Renjith, Anu; Roy, Arun; Lakshminarayanan, V

2014-07-15

We describe here a simple electrodeposition process of forming thin films of noble metallic nanoparticles such as Au, Ag and Pd in deep eutectic solvents (DES). The method consists of anodic dissolution of the corresponding metal in DES followed by the deposition on the cathodic surface. The anodic dissolution process in DES overcomes the problems associated with copious hydrogen and oxygen evolution on the electrode surface when carried out in aqueous medium. The proposed method utilizes the inherent abilities of DES to act as a reducing medium while simultaneously stabilizing the nanoparticles that are formed. The mesoporous metal films were characterized by SEM, XRD and electrochemical techniques. Potential applications of these substrates in surface enhanced Raman spectroscopy and electrocatalysis have been investigated. A large enhancement of Raman signal of analyte was achieved on the mesoporous silver substrate after removing all the stabilizer molecules from the surface by calcination. The highly porous texture of the electrodeposited film provides superior electro catalytic performance for hydrogen evolution reaction (HER). The mechanisms of HER on the fabricated substrates were studied by Tafel analysis and electrochemical impedance spectroscopy (EIS). Copyright © 2014 Elsevier Inc. All rights reserved.

Thermal simulation of the magnesium thermal of metallic uranium reduction

International Nuclear Information System (INIS)

Borges, W.A.; Saliba-Silva, A.M.

2008-01-01

Metallic uranium production is vital to fabricate fuel elements for nuclear research reactors and to produce radioisotopes and radiopharmaceuticals. Metallic uranium is got via magnesiothermal reduction of UF 4 . This reaction is carried out inside a closed graphite crucible inserted in a metallic reactor adequately sealed without any outside contact. The assembled set is gradually heated up inside a pit furnace up to reach the reaction ignition temperature (between 600-650 deg C). The optimization of the reactive system depends on the mathematical modeling using simulation by finite elements and computational calculation with specialized programs. In this way, the reactants' thermal behavior is forecast until they reach the ignition temperature. The optimization of the uranium production reaction is based on minimization of thermal losses using better the exo thermal reaction heat. As lower the thermal losses, as higher would be the heat amount to raise the temperature of reaction products. This promotes the adequate melting of uranium and slag, so allowing better metal/slag separation with higher metallic yield. This work shows how the mathematical simulation is made and supplies some preliminary results. (author)

Math on the Job. Metal Product Assembler.

Science.gov (United States)

Ohio State Univ., Columbus. National Center for Research in Vocational Education.

This booklet is intended to help mainstreamed mentally retarded, emotionally disturbed, or learning disabled high school students acquire a basic understanding of the responsibilities and working conditions of metal product assemblers and to practice basic math skills necessary in the occupation. The first section provides a brief introduction to…

PRODUCTION OF PROTOTYPE PARTS USING DIRECT METAL LASER SINTERING TECHNOLOGY

Directory of Open Access Journals (Sweden)

Josef Sedlak

2015-08-01

Full Text Available Unconventional methods of modern materials preparation include additive technologies which involve the sintering of powders of different chemical composition, granularity, physical, chemical and other utility properties. The technology called Rapid Prototyping, which uses different technological principles of producing components, belongs to this type of material preparation. The Rapid Prototyping technology facilities use photopolymers, thermoplastics, specially treated paper or metal powders. The advantage is the direct production of metal parts from input data and the fact that there is no need for the production of special tools (moulds, press tools, etc.. Unused powder from sintering technologies is re-used for production 98% of the time, which means that the process is economical, as well as ecological.The present paper discusses the technology of Direct Metal Laser Sintering (DMLS, which falls into the group of additive technologies of Rapid Prototyping (RP. The major objective is a detailed description of DMLS, pointing out the benefits it offers and its application in practice. The practical part describes the production and provides an economic comparison of several prototype parts that were designed for testing in the automotive industry.

Comparison of Jacket Production Processes Designed by Fabric Materials and Leather

OpenAIRE

Emine Utkun; Ziynet Öndoğan

2011-01-01

Leather and leather products industry has shown a significant improvement in export area, as a result of intensive shuttle trades and demand that comes from crumbling Eastern Bloc countries in 1990's. This development has caused capacity increasing and thus makes large investments in this sector. Leather garment industry differs from woven or fabrics industry at various points. Differantation seems in raw materials features such as size, thickness, biological, chemical or physical homogenity....

Injectable dextran hydrogels fabricated by metal-free click chemistry for cartilage tissue engineering.

Science.gov (United States)

Wang, Xiaoyu; Li, Zihan; Shi, Ting; Zhao, Peng; An, Kangkang; Lin, Chao; Liu, Hongwei

2017-04-01

Injectable dextran-based hydrogels were prepared for the first time by bioorthogonal click chemistry for cartilage tissue engineering. Click-crosslinked injectable hydrogels based on cyto-compatible dextran (Mw=10kDa) were successfully fabricated under physiological conditions by metal-free alkyne-azide cycloaddition (click) reaction between azadibenzocyclooctyne-modified dextran (Dex-ADIBO) and azide-modified dextran (Dex-N 3 ). Gelation time of these dextran hydrogels could be regulated in the range of approximately 1.1 to 10.2min, depending on the polymer concentrations (5% or 10%) and ADIBO substitution degree (DS, 5 or 10) of Dex-ADIBO. Rheological analysis indicated that the dextran hydrogels were elastic and had storage moduli from 2.1 to 6.0kPa with increasing DS of ADIBO from 5 to 10. The in vitro tests revealed that the dextran hydrogel crosslinked from Dex-ADIBO DS 10 and Dex-N 3 DS 10 at a polymer concentration of 10% could support high viability of individual rabbit chondrocytes and the chondrocyte spheroids encapsulated in the hydrogel over 21days. Individual chondrocytes and chondrocyte spheroids in the hydrogel could produce cartilage matrices such as collagen and glycosaminoglycans. However, the chondrocyte spheroids produced a higher content of matrices than individual chondrocytes. This study indicates that metal-free click chemistry is effective to produce injectable dextran hydrogels for cartilage tissue engineering. Copyright © 2016 Elsevier B.V. All rights reserved.

Fabrication of Metal Nanoparticle Arrays in the ZrO2(Y, HfO2(Y, and GeOx Films by Magnetron Sputtering

Directory of Open Access Journals (Sweden)

Oleg Gorshkov

2017-01-01

Full Text Available The single sheet arrays of Au nanoparticles (NPs embedded into the ZrO2(Y, HfO2(Y, and GeOx (x≈2 films have been fabricated by the alternating deposition of the nanometer-thick dielectric and metal films using Magnetron Sputtering followed by annealing. The structure and optical properties of the NP arrays have been studied, subject to the fabrication technology parameters. The possibility of fabricating dense single sheet Au NP arrays in the matrices listed above with controlled NP sizes (within 1 to 3 nm and surface density has been demonstrated. A red shift of the plasmonic optical absorption peak in the optical transmission spectra of the nanocomposite films (in the wavelength band of 500 to 650 nm has been observed. The effect was attributed to the excitation of the collective surface plasmon-polaritons in the dense Au NP arrays. The nanocomposite films fabricated in the present study can find various applications in nanoelectronics (e.g., single electronics, nonvolatile memory devices, integrated optics, and plasmonics.

Fabrication of multilayer nanowires

Energy Technology Data Exchange (ETDEWEB)

Kaur, Jasveer, E-mail: kaurjasveer89@gmail.com; Singh, Avtar; Kumar, Davinder [Department of Physics, Punjabi University Patiala, 147002, Punjab (India); Thakur, Anup; Kaur, Raminder, E-mail: raminder-k-saini@yahoo.com [Department of Basic and Applied Sciences, Punjabi University Patiala, 147002, Punjab (India)

2016-05-06

Multilayer nanowires were fabricated by potentiostate ectrodeposition template synthesis method into the pores of polycarbonate membrane. In present work layer by layer deposition of two different metals Ni and Cu in polycarbonate membrane having pore size of 600 nm were carried out. It is found that the growth of nanowires is not constant, it varies with deposition time. Scanning electron microscopy (SEM) is used to study the morphology of fabricated multilayer nanowires. An energy dispersive X-ray spectroscopy (EDS) results confirm the composition of multilayer nanowires. The result shows that multilayer nanowires formed is dense.

Fabrication of multilayer nanowires

International Nuclear Information System (INIS)

Kaur, Jasveer; Singh, Avtar; Kumar, Davinder; Thakur, Anup; Kaur, Raminder

2016-01-01

Multilayer nanowires were fabricated by potentiostate ectrodeposition template synthesis method into the pores of polycarbonate membrane. In present work layer by layer deposition of two different metals Ni and Cu in polycarbonate membrane having pore size of 600 nm were carried out. It is found that the growth of nanowires is not constant, it varies with deposition time. Scanning electron microscopy (SEM) is used to study the morphology of fabricated multilayer nanowires. An energy dispersive X-ray spectroscopy (EDS) results confirm the composition of multilayer nanowires. The result shows that multilayer nanowires formed is dense.