WorldWideScience

Sample records for sacrificial layer materials

  1. Dendritic materials as a dry release sacrificial layer

    Science.gov (United States)

    Suh, Hyuk-Jeen

    2001-07-01

    A class of polymers known as dendritic materials has been studied for use as a sacrificial layer in microelectromechanical systems (MEMS) fabrication. This thesis describes the material characterization and process development of dendritic materials for a dry sacrificial layer etching process. A less structured type of dendritic material known as hyperbranched polymers in particular was studied to prevent stiction. Chapter 2 provides a quick overview of stiction theory and some of the current techniques used to address the problem. A particular hyperbranched polymer known as HB560 was synthesized at the University of Illinois at Urbana-Champaign. HB560 has a high glass transition temperature so that the material decomposes without passing through a liquid phase. The lack of a liquid phase transition allows the material to be used as a dry sacrificial layer for MEMS fabrication. Material characterization of HBPs is described in Chapter 3 and process development and integration with MEMS fabrication are outlined in Chapter 4. Various test devices were successfully fabricated using the developed process to demonstrate a dry sacrificial etching technique. An array of cantilever beams 100 mum in width by 1000 mum in length was successfully released in 10 min. In addition, an array of microchannels was fabricated to better understand the limitations of HB560 decomposition. A full 1-cm-long microchannel with longitudinal aspect ratio of 16 600 was successfully realized in 10 min. A comparison study with other techniques shows that HB560 etching is on the order of 200 times faster than a 49% HF wet etching techniques used in MEMS fabrication. A published process with a faster etch rate could not be found. In order to demonstrate the large sacrificial etching capabilities of HB560 as well as its unique material characteristics, a microblister pack chamber, 5000 mum in diameter and nearly 2 cm in length, was successfully fabricated. A lateral aspect ratio of 8300 and a longitudinal aspect ratio of 31 000 were achieved and described in Chapter 5. Chapter 6 summarizes the thesis with discussions pertaining to future work.

  2. SU-8 Based MEMS Process with Two Metal Layers using α-Si as a Sacrificial Material

    KAUST Repository

    Ramadan, Khaled S.

    2012-04-01

    Polymer based microelectromechanical systems (MEMS) micromachining is finding more interest in research and applications. This is due to its low cost and less time processing compared with silicon MEMS. SU-8 is a photo-patternable polymer that is used as a structural layer for MEMS and microfluidic devices. In addition to being processed with low cost, it is a biocompatible material with good mechanical properties. Also, amorphous silicon (α-Si) has found use as a sacrificial layer in silicon MEMS applications. α-Si can be deposited at large thicknesses for MEMS applications and also can be released in a dry method using XeF2 which can solve stiction problems related to MEMS applications. In this thesis, an SU-8 MEMS process is developed using amorphous silicon (α-Si) as a sacrificial layer. Electrostatic actuation and sensing is used in many MEMS applications. SU-8 is a dielectric material which limits its direct use in electrostatic actuation. This thesis provides a MEMS process with two conductive metal electrodes that can be used for out-of-plane electrostatic applications like MEMS switches and variable capacitors. The process provides the fabrication of dimples that can be conductive or non-conductive to facilitate more flexibility for MEMS designers. This SU-8 process can fabricate SU-8 MEMS structures of a single layer of two different thicknesses. Process parameters were tuned for two sets of thicknesses which are thin (5-10μm) and thick (130μm). Chevron bent-beam structures and different suspended beams (cantilevers and bridges) were fabricated to characterize the SU-8 process through extracting the density, Young’s Modulus and the Coefficient of Thermal Expansion (CTE) of SU-8. Also, the process was tested and used as an educational tool through which different MEMS structures were fabricated including MEMS switches, variable capacitors and thermal actuators.

  3. Fabrication of polyimide sacrificial layers with inclined sidewalls based on reactive ion etching

    OpenAIRE

    Yuanjing Chen; Haiyang Mao; Qiulin Tan; Chenyang Xue; Wen Ou; Jin Liu; Dapeng Chen

    2014-01-01

    Polyimide is used as a sacrificial material because of its low stress, its removable ability and its compatibility with standard micromachining processes. In this work, polyimide structures with inclined sidewalls are fabricated with a reactive ion etching process, where SiO2 is used as the hard-mask material. The structures can be further used as sacrificial layers in micro-electro-mechanical systems infrared (IR) sensors to support IR absorbers, to realize the thermal connections between th...

  4. PostCMOS compatible sacrificial layers for aluminum nitride microcantilevers

    Science.gov (United States)

    Prez-Campos, Ana; Iriarte, Gonzalo Fuentes; Lebedev, Vadim; Calle, Fernando

    2014-10-01

    This report shows different fabrication procedures followed to obtain piezoelectric microcantilevers. The proposed microcantilever is a sandwich structure composed of chromium (Cr) electrodes (from 50 to 300-nm thick) and a reactive sputtered piezoelectric aluminum nitride (AlN) thin film (from 350 nm to 600-nm thick). The microcantilevers top-view dimensions ranged from 50 to 300 ?m in width and from to 250 to 700 ?m in length. Several materials such as nickel silicide and nickel, as well as a photoresist, and finally the silicon substrate surface have been investigated to discern their possibilities and limitations when used as sacrificial layers. These materials have been studied to determine the optimal processing steps and chemistries required for each of them. The easiest and the only successful microcantilevers release was finally obtained using the top silicon substrate surface as a sacrificial layer. The structural and morphological characteristics of the microcantilevers are presented as well as their piezoelectric character. The main difference of this work resides in the Si surface-based microcantilever release technique. This, along with the synthesis of AlN at room temperature by reactive sputtering, establishes a manufacturing procedure for piezoelectric microbeams, which makes possible the integration of such MEMS devices into postCMOS technology.

  5. Methods of producing free-standing semiconductors using sacrificial buffer layers and recyclable substrates

    Science.gov (United States)

    Ptak, Aaron Joseph; Lin, Yong; Norman, Andrew; Alberi, Kirstin

    2015-05-26

    A method of producing semiconductor materials and devices that incorporate the semiconductor materials are provided. In particular, a method is provided of producing a semiconductor material, such as a III-V semiconductor, on a spinel substrate using a sacrificial buffer layer, and devices such as photovoltaic cells that incorporate the semiconductor materials. The sacrificial buffer material and semiconductor materials may be deposited using lattice-matching epitaxy or coincident site lattice-matching epitaxy, resulting in a close degree of lattice matching between the substrate material and deposited material for a wide variety of material compositions. The sacrificial buffer layer may be dissolved using an epitaxial liftoff technique in order to separate the semiconductor device from the spinel substrate, and the spinel substrate may be reused in the subsequent fabrication of other semiconductor devices. The low-defect density semiconductor materials produced using this method result in the enhanced performance of the semiconductor devices that incorporate the semiconductor materials.

  6. Performance characterization of geopolymer composites for hot sodium exposed sacrificial layer in fast breeder reactors

    International Nuclear Information System (INIS)

    Highlights: Performance evaluation of geopolymers subjected to hot liquid sodium is performed. Apart from mechanical properties, micro-analytical techniques are used for material characterization. The geopolymer composite showed comparatively lesser damage than conventional cement composites. Geopolymer technology can emerge as a new choice for sacrificial layer in SCFBRs. - Abstract: A sacrificial layer of concrete is used in sodium cooled fast breeder reactors (SCFBRs) to mitigate thermo-chemical effect of accidentally spilled sodium at and above 550 C on structural concrete. Performance of this layer is governed by thermo-chemical stability of the ingredients of sacrificial layer concrete. Concrete with limestone aggregate is generally used as a sacrificial layer. Conventional cement based systems exhibit instability in hot liquid sodium environment. Geo-polymer composites are well known to perform excellently at elevated temperatures compared to conventional cement systems. This paper discusses performance of such composites subjected to exposure of hot liquid sodium in air. The investigation includes comprehensive evaluation of various geo-polymer composites before any exposure, after heating to 550 C in air, and after immersing in hot liquid sodium initially heated to 550 C in air. Results from the current study indicate that hot liquid sodium produces less damage to geopolymer composites than to the existing conventional cement based system. Hence, the geopolymer technology has potential application in mitigating the degrading effects of sodium fires and can emerge as a new choice for sodium exposed sacrificial layer in SCFBRs

  7. Performance characterization of geopolymer composites for hot sodium exposed sacrificial layer in fast breeder reactors

    Energy Technology Data Exchange (ETDEWEB)

    Haneefa, K. Mohammed, E-mail: mhkolakkadan@gmail.com [Department of Civil Engineering, IIT Madras, Chennai (India); Santhanam, Manu [Department of Civil Engineering, IIT Madras, Chennai (India); Parida, F.C. [Radiological Safety Division, Indira Gandhi Centre for Atomic Research, Kalpakkam (India)

    2013-12-15

    Highlights: Performance evaluation of geopolymers subjected to hot liquid sodium is performed. Apart from mechanical properties, micro-analytical techniques are used for material characterization. The geopolymer composite showed comparatively lesser damage than conventional cement composites. Geopolymer technology can emerge as a new choice for sacrificial layer in SCFBRs. - Abstract: A sacrificial layer of concrete is used in sodium cooled fast breeder reactors (SCFBRs) to mitigate thermo-chemical effect of accidentally spilled sodium at and above 550 C on structural concrete. Performance of this layer is governed by thermo-chemical stability of the ingredients of sacrificial layer concrete. Concrete with limestone aggregate is generally used as a sacrificial layer. Conventional cement based systems exhibit instability in hot liquid sodium environment. Geo-polymer composites are well known to perform excellently at elevated temperatures compared to conventional cement systems. This paper discusses performance of such composites subjected to exposure of hot liquid sodium in air. The investigation includes comprehensive evaluation of various geo-polymer composites before any exposure, after heating to 550 C in air, and after immersing in hot liquid sodium initially heated to 550 C in air. Results from the current study indicate that hot liquid sodium produces less damage to geopolymer composites than to the existing conventional cement based system. Hence, the geopolymer technology has potential application in mitigating the degrading effects of sodium fires and can emerge as a new choice for sodium exposed sacrificial layer in SCFBRs.

  8. Use of silicon oxynitride as a sacrificial material for microelectromechanical devices

    Science.gov (United States)

    Habermehl, Scott D. (Corrales, NM); Sniegowski, Jeffry J. (Edgewood, NM)

    2001-01-01

    The use of silicon oxynitride (SiO.sub.x N.sub.y) as a sacrificial material for forming a microelectromechanical (MEM) device is disclosed. Whereas conventional sacrificial materials such as silicon dioxide and silicate glasses are compressively strained, the composition of silicon oxynitride can be selected to be either tensile-strained or substantially-stress-free. Thus, silicon oxynitride can be used in combination with conventional sacrificial materials to limit an accumulation of compressive stress in a MEM device; or alternately the MEM device can be formed entirely with silicon oxynitride. Advantages to be gained from the use of silicon oxynitride as a sacrificial material for a MEM device include the formation of polysilicon members that are substantially free from residual stress, thereby improving the reliability of the MEM device; an ability to form the MEM device with a higher degree of complexity and more layers of structural polysilicon than would be possible using conventional compressively-strained sacrificial materials; and improved manufacturability resulting from the elimination of wafer distortion that can arise from an excess of accumulated stress in conventional sacrificial materials. The present invention is useful for forming many different types of MEM devices including accelerometers, sensors, motors, switches, coded locks, and flow-control devices, with or without integrated electronic circuitry.

  9. Formulation and processing of screen-printing vehicles for sacrificial layers on thick-film and LTCC substrates

    OpenAIRE

    Maeder, Thomas; Jacq, Caroline; Fournier, Yannick; Ryser, Peter

    2008-01-01

    Ceramic technologies such as thick-film and LTCC (Low Temperature Cofired Ceramic) are excellent platforms for the fabrication of mesoscale devices such as sensors, actuators, microreactors and MEMS packaging. This work presents two alternative screen-printing vehicles for the processing of sacrificial materials and low-firing thick films: 1) a non-aggressive glycol-based vehicle for screen printing thick sacrificial layers onto thin LTCC, and 2) a "high non-evaporables" vehicle for mineral /...

  10. Fabrication of polyimide sacrificial layers with inclined sidewalls based on reactive ion etching

    Directory of Open Access Journals (Sweden)

    Yuanjing Chen

    2014-03-01

    Full Text Available Polyimide is used as a sacrificial material because of its low stress, its removable ability and its compatibility with standard micromachining processes. In this work, polyimide structures with inclined sidewalls are fabricated with a reactive ion etching process, where SiO2 is used as the hard-mask material. The structures can be further used as sacrificial layers in micro-electro-mechanical systems infrared (IR sensors to support IR absorbers, to realize the thermal connections between the absorbers and the thermopiles, and to scale down the size of the sensors. As a result, IR sensors with low-residual-stress absorption, high structural stability, low heat loss and small dimensions can be achieved.

  11. Fabrication of polyimide sacrificial layers with inclined sidewalls based on reactive ion etching

    Science.gov (United States)

    Chen, Yuanjing; Mao, Haiyang; Tan, Qiulin; Xue, Chenyang; Ou, Wen; Liu, Jin; Chen, Dapeng

    2014-03-01

    Polyimide is used as a sacrificial material because of its low stress, its removable ability and its compatibility with standard micromachining processes. In this work, polyimide structures with inclined sidewalls are fabricated with a reactive ion etching process, where SiO2 is used as the hard-mask material. The structures can be further used as sacrificial layers in micro-electro-mechanical systems infrared (IR) sensors to support IR absorbers, to realize the thermal connections between the absorbers and the thermopiles, and to scale down the size of the sensors. As a result, IR sensors with low-residual-stress absorption, high structural stability, low heat loss and small dimensions can be achieved.

  12. Selective etchant for oxide sacrificial material in semiconductor device fabrication

    Science.gov (United States)

    Clews, Peggy J.; Mani, Seethambal S.

    2005-05-17

    An etching composition and method is disclosed for removing an oxide sacrificial material during manufacture of semiconductor devices including micromechanical, microelectromechanical or microfluidic devices. The etching composition and method are based on the combination of hydrofluoric acid (HF) and sulfuric acid (H.sub.2 SO.sub.4). These acids can be used in the ratio of 1:3 to 3:1 HF:H.sub.2 SO.sub.4 to remove all or part of the oxide sacrificial material while providing a high etch selectivity for non-oxide materials including polysilicon, silicon nitride and metals comprising aluminum. Both the HF and H.sub.2 SO.sub.4 can be provided as "semiconductor grade" acids in concentrations of generally 40-50% by weight HF, and at least 90% by weight H.sub.2 SO.sub.4.

  13. Structuration of zero-shrinkage LTCC using mineral sacrificial materials

    OpenAIRE

    Maeder, Thomas; Jacq, Caroline; Fournier, Yannick; Hraiz, Wassim; Ryser, Peter

    2009-01-01

    Recently, LTCC (low-temperature co-fired ceramic) technology has increasingly found applications beyond pure electronics, in fields such as microfluidics, sensors and actuators, due to the ease of shaping the tapes in the green (unfired) state. Accurate control of hollow structures such as channels, membranes, cavities and gaps below cantilevers has remained difficult, however, although carbon-based sacrificial materials and adhesive/solvent-assisted low-pressure lamination techni...

  14. A novel method for sacrificial layer release in MEMS devices fabrication

    International Nuclear Information System (INIS)

    During the forming process of the free-standing structure or the functional cavity when releasing the high aspect ratio sacrificial layer, such structures tend to stick to the substrate due to capillary force. This paper describes the application of pull-in length conception as design rules to a novel 'dimpled' method in releasing sacrificial layer. Based on the conception of pull-in length in adhering phenomenon, the fabrication and releasing sacrificial layer methods using micro bumps based on the silicon substrate were presented. According to the thermal isolation performances of one kind of micro electromechanical system device thermal shear stress sensor, the sacrificial layers were validated to be successfully released. (condensed matter: structure, thermal and mechanical properties)

  15. New sacrificial material for ex-vessel core catcher

    Science.gov (United States)

    Komlev, Andrei A.; Almjashev, Vyacheslav I.; Bechta, Sevostian V.; Khabensky, Vladimir B.; Granovsky, Vladimir S.; Gusarov, Victor V.

    2015-12-01

    A new functional (sacrificial) material has been developed in the Fe2O3-SrO-Al2O3-CaO system based on strontium hexaferrite ceramic in concrete matrix. The method of producing SM has been advanced technologically; this technological effectiveness allows the SM to be used in ex-vessel core catchers with corium spreading as well as in crucible-type core catchers. Critical properties regarding the efficiency of SM in ex-vessel core catchers, such as porosity, pycnometric density, apparent density, solidus and liquidus temperatures, and water content have been measured. Suitable fractions of SrFe12O19 and high alumina cement (HAC) were found in the SM based on thermodynamic analysis of the SM/corium interaction. The use of sacrificial steel as an additional heat adsorption component in the core catcher allowed us to increase the mass fraction range of SrFe12O19 in the SM from 0.3-0.5 to 0.3-0.85. The activation temperature of the SM/corium interaction has been shown to correspond to the liquidus temperature of the local composition at the SM/corium interface. The calculated value of this temperature was 1716 °C. Analysis of phase transformations in the SrO-Fe2O3 system revealed advantages of the SrFe12O19-based sacrificial material compared with the Fe2O3-contained material owing to the time proximity of SrFe12O19 decomposition and corium interaction activation.

  16. Formation of thick spin-on glass (SOG) sacrificial layer for capacitive accelerometer encapsulation

    Science.gov (United States)

    Hamzah, Azrul A.; Majlis, Burhanuddin Y.; Ahmad, Ibrahim

    2006-01-01

    This paper presents a method to form thick spin-on glass (SOG) sacrificial layer for accelerometer encapsulation fabrication. SOG is chosen as the sacrificial material because it is easy to apply, has good thickness uniformity, and can be easily etched back before densification. Siloxane type SOG is applied on blank wafers and accelerometer patterns by multiple spin, bake, and cure processes. A series of gradual hot plate baking up to 250C are experimented for each spun layer. After multiple spin and bake, the SOG layers are etched back in hydrofluoric acid (HF) solution of various concentrations to form rectangular encapsulation bases. 25 samples are prepared for SOG thickness uniformity characterization. Center thickness and four perimeter thickness measurements are taken for each sample using thin-film mapper. These five measurements are averaged to get sample thickness. Two surface profiler measurements are taken for each sample perpendicularly to each other using Tencor surface profiler. The minimum reading is subtracted from the maximum reading to get sample variation. Upon SEM inspection, mildly sloped etched walls from HF etching are observed. No surface cracking was visible. Shallow trench patterns are apparent on SOG deposited on accelerometer pattern. The average sample thickness is 5 ?m with 3.7% thickness variation across samples. The average variation within each sample is 0.14 ?m with an average of 2.6% thickness variation within sample. These thickness variations are acceptable for encapsulation structure deposition.

  17. Method of Manufacturing A Porous Polymer Component Involving Use of A Dissolvable, Sacrificial Material

    DEFF Research Database (Denmark)

    Mohanty, Soumyaranjan Technical University of Denmark,

    The present invention relates to a method of manufacturing a porous polymer component 1 with structured and/or random pores 4 and/or channels 5. The method comprises arranging a dissolvable, sacrificial material 2 in a geometrical arrangement corresponding to an inner structure to be obtained in the polymer component 1. A component material 3, which is to form the final component 1, is arranged so that it surrounds at least a majority of the sacrificial material 2, and subsequently the sacrificial material 2 is dissolved and removed from the component material 3. The sacrificial material 2 and thereby the resulting inner structure of the component 1 is arranged in a controlled and reproducible manner. The sacrificial material 2 and possibly also the component material 3 may e.g. be arranged by use of a 3D-printer or manually. The method may e.g. be used to manufacture a three-dimensional scaffold for tissue engineering.

  18. Method of using sacrificial materials for fabricating internal cavities in laminated dielectric structures

    Science.gov (United States)

    Peterson, Kenneth A. (Albuquerque, NM)

    2009-02-24

    A method of using sacrificial materials for fabricating internal cavities and channels in laminated dielectric structures, which can be used as dielectric substrates and package mounts for microelectronic and microfluidic devices. A sacrificial mandrel is placed in-between two or more sheets of a deformable dielectric material (e.g., unfired LTCC glass/ceramic dielectric), wherein the sacrificial mandrel is not inserted into a cutout made in any of the sheets. The stack of sheets is laminated together, which deforms the sheet or sheets around the sacrificial mandrel. After lamination, the mandrel is removed, (e.g., during LTCC burnout), thereby creating a hollow internal cavity in the monolithic ceramic structure.

  19. Homeotropic Alignment of a Discotic Liquid Crystal Induced by a Sacrificial Layer

    DEFF Research Database (Denmark)

    Pouzet, Eric; De Cupere, Vinciane; Heintz, Christophe; Andreasen, Jens Wenzel; Breiby, Dag Werner; Nielsen, Martin Meedom; Viville, Pascal; Lazzaroni, Roberto; Gbabode, Gabin; Geerts, Yves H.

    2009-01-01

    A convenient method to induce face-on orientation of an alkoxy phtalocyanine discotic mesogen is described. The alignment is imposed by the confinement of the discotic thin films with a top sacrificial polymer layer that is easily removed by washing with a selective solvent, after thermal anneali...

  20. Homeotropic Alignment of a Discotic Liquid Crystal Induced by a Sacrificial Layer

    DEFF Research Database (Denmark)

    Pouzet, Eric; De Cupere, Vinciane

    2009-01-01

    A convenient method to induce face-on orientation of an alkoxy phtalocyanine discotic mesogen is described. The alignment is imposed by the confinement of the discotic thin films with a top sacrificial polymer layer that is easily removed by washing with a selective solvent, after thermal annealing. Thin films have been characterized by optical and atomic force microscopy, UV-Vis absorption spectroscopy, and grazing incidence wide angle X-ray scattering. The data converge in showing the central role of the sacrificial layer in promoting alignment with the planar molecules orienting parallel to the substrate in an essentially homeotropic arrangement over large lateral length scales and the persistence of this desirable alignment after removal of the layer.

  1. Development of an SU-8 MEMS process with two metal electrodes using amorphous silicon as a sacrificial material

    KAUST Repository

    Ramadan, Khaled S.

    2013-02-08

    This work presents an SU-8 surface micromachining process using amorphous silicon as a sacrificial material, which also incorporates two metal layers for electrical excitation. SU-8 is a photo-patternable polymer that is used as a structural layer for MEMS and microfluidic applications due to its mechanical properties, biocompatibility and low cost. Amorphous silicon is used as a sacrificial layer in MEMS applications because it can be deposited in large thicknesses, and can be released in a dry method using XeF2, which alleviates release-based stiction problems related to MEMS applications. In this work, an SU-8 MEMS process was developed using ;-Si as a sacrificial layer. Two conductive metal electrodes were integrated in this process to allow out-of-plane electrostatic actuation for applications like MEMS switches and variable capacitors. In order to facilitate more flexibility for MEMS designers, the process can fabricate dimples that can be conductive or nonconductive. Additionally, this SU-8 process can fabricate SU-8 MEMS structures of a single layer of two different thicknesses. Process parameters were optimized for two sets of thicknesses: thin (5-10 m) and thick (130 m). The process was tested fabricating MEMS switches, capacitors and thermal actuators. © 2013 IOP Publishing Ltd.

  2. Fabrication of LTCC Micro-fluidic Devices Using Sacrificial Carbon Layers

    OpenAIRE

    Birol, Hansu; Maeder, Thomas; Jacq, Caroline; Corradini, Giancarlo; Passerini, Reynald; Fournier, Yannick; Strssler, Sigfrid; Ryser, Peter

    2005-01-01

    Ease of fabrication and design flexibility are two attractive features of low temperature co-fired ceramics (LTCC) technology for fabrication of complex micro-fluidic devices. Such structures are designed and processed using different shaping methods, the extent and complexity of which depends on the final device specifications (dimensions, mechanical and functional properties). In this work, we propose a sacrificial layer method based on carbon-black paste, which burns out during the L...

  3. A novel sacrificial-layer process based on anodic bonding and its application in an accelerometer

    Science.gov (United States)

    Wang, Lingyun; He, Yong; Zhan, Zhan; Yu, Lingke; Wang, Huan; Chen, Daner

    2015-04-01

    It is found in our experiments that the depletion layer of anodic bonding is etched faster than the bulk glass (Pyrex 7740) in hydrofluoric acid (HF). Based on this interesting phenomenon, a novel process of a sacrificial layer is proposed in this paper. In order to deeply understand and investigate the rules concerning the influence of bonding parameters on this effect, firstly the width of the depletion layer under different bonding voltages and temperatures and the selection ratio of etching are revealed. To validate the feasibility of the method, a micro-machined accelerometer is designed and fabricated. The test results of resonant frequency and sensitivity of the fabricated accelerometer are 3254.5 Hz and 829.85-844.93 mV/g, respectively. This was further evidence that the depletion layer could be used as a sacrificial layer and the removable structure could be successfully released by fast etching this layer. The important feature of this method is that only one mask is needed in the whole process and therefore it could greatly simplify the fabrication process of the device.

  4. Method of Manufacturing A Porous Polymer Component Involving Use of A Dissolvable, Sacrificial Material

    DEFF Research Database (Denmark)

    and thereby the resulting inner structure of the component 1 is arranged in a controlled and reproducible manner. The sacrificial material 2 and possibly also the component material 3 may e.g. be arranged by use of a 3D-printer or manually. The method may e.g. be used to manufacture a three...

  5. Fabrication of relaxer-based piezoelectric energy harvesters using a sacrificial poly-Si seeding layer

    KAUST Repository

    Fuentes-Fernandez, E. M A

    2014-08-07

    The effect of a polycrystalline silicon (poly-Si) seeding layer on the properties of relaxor Pb(Zr0.53,Ti0.47)O3-Pb(Zn1/3,Nb2/3)O3 (PZT-PZN) thin films and energy-harvesting cantilevers was studied. We deposited thin films of the relaxor on two substrates, with and without a poly-Si seeding layer. The seeding layer, which also served as a sacrificial layer to facilitate cantilever release, was found to improve morphology, phase purity, crystal orientation, and electrical properties. We attributed these results to reduction of the number of nucleation sites and, therefore, to an increase in relaxor film grain size. The areal power density of the wet-based released harvester was measured. The power density output of the energy harvester with this relaxor composition and the poly-Si seeding layer was 325 μW/cm2.

  6. Rolled-Up Nanotech: Illumination-Controlled Hydrofluoric Acid Etching of AlAs Sacrificial Layers

    OpenAIRE

    Costescu Ruxandra; Deneke Christoph; Thurmer Dominic; Schmidt Oliver

    2009-01-01

    Abstract The effect of illumination on the hydrofluoric acid etching of AlAs sacrificial layers with systematically varied thicknesses in order to release and roll up InGaAs/GaAs bilayers was studied. For thicknesses of AlAs below 10 nm, there were two etching regimes for the area under illumination: one at low illumination intensities, in which the etching and releasing proceeds as expected and one at higher intensities in which the etching and any releasing are completely suppressed. The &#...

  7. Enhancing mechanical performance of a covalent self-healing material by sacrificial noncovalent bonds.

    Science.gov (United States)

    Neal, James A; Mozhdehi, Davoud; Guan, Zhibin

    2015-04-15

    Polymers that repair themselves after mechanical damage can significantly improve their durability and safety. A major goal in the field of self-healing materials is to combine robust mechanical and efficient healing properties. Here, we show that incorporation of sacrificial bonds into a self-repairable network dramatically improves the overall mechanical properties. Specifically, we use simple secondary amide side chains to create dynamic energy dissipative hydrogen bonds in a covalently cross-linked polymer network, which can self-heal via olefin cross-metathesis. We envision that this straightforward sacrificial bonding strategy can be employed to improve mechanical properties in a variety of self-healing systems. PMID:25790015

  8. Film transfer enabled by nanosheet seed layers on arbitrary sacrificial substrates

    Energy Technology Data Exchange (ETDEWEB)

    Dral, A. P.; Nijland, M.; Koster, G.; Elshof, J. E. ten, E-mail: j.e.tenelshof@utwente.nl [MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede (Netherlands)

    2015-05-01

    An approach for film transfer is demonstrated that makes use of seed layers of nanosheets on arbitrary sacrificial substrates. Epitaxial SrTiO{sub 3}, SrRuO{sub 3}, and BiFeO{sub 3} films were grown on Ca{sub 2}Nb{sub 3}O{sub 10} nanosheet seed layers on phlogopite mica substrates. Cleavage of the mica substrates enabled film transfer to flexible polyethylene terephthalate substrates. Electron backscatter diffraction, X-ray diffraction, and atomic force microscopy confirmed that crystal orientation and film morphology remained intact during transfer. The generic nature of this approach is illustrated by growing films on zinc oxide substrates with a nanosheet seed layer. Film transfer to a flexible substrate was accomplished via acid etching.

  9. Film transfer enabled by nanosheet seed layers on arbitrary sacrificial substrates

    Directory of Open Access Journals (Sweden)

    A. P. Dral

    2015-05-01

    Full Text Available An approach for film transfer is demonstrated that makes use of seed layers of nanosheets on arbitrary sacrificial substrates. Epitaxial SrTiO3, SrRuO3, and BiFeO3 films were grown on Ca2Nb3O10 nanosheet seed layers on phlogopite mica substrates. Cleavage of the mica substrates enabled film transfer to flexible polyethylene terephthalate substrates. Electron backscatter diffraction, X-ray diffraction, and atomic force microscopy confirmed that crystal orientation and film morphology remained intact during transfer. The generic nature of this approach is illustrated by growing films on zinc oxide substrates with a nanosheet seed layer. Film transfer to a flexible substrate was accomplished via acid etching.

  10. Multiscale ommatidial arrays with broadband and omnidirectional antireflection and antifogging properties by sacrificial layer mediated nanoimprinting.

    Science.gov (United States)

    Raut, Hemant Kumar; Dinachali, Saman Safari; Loke, Yee Chong; Ganesan, Ramakrishnan; Ansah-Antwi, Kwadwo Konadu; Gra, Aleksander; Khoo, Eng Huat; Ganesh, V Anand; Saifullah, Mohammad S M; Ramakrishna, Seeram

    2015-02-24

    Moth's eye inspired multiscale ommatidial arrays offer multifunctional properties of great significance in optoelectronic devices. However, a major challenge remains in fabricating these arrays on large-area substrates using a simple and scalable technique. Here we present the fabrication of these multiscale ommatidial arrays over large areas by a distinct approach called sacrificial layer mediated nanoimprinting, which involves nanoimprinting aided by a sacrificial layer. The fabricated arrays exhibited excellent pattern uniformity over the entire patterned area. Optimum dimensions of the multiscale ommatidial arrays determined by the finite-difference time domain simulations served as the design parameters for replicating the arrays on glass. A broadband suppression of reflectance to a minimum of ?1.4% and omnidirectional antireflection for highly oblique angles of incidence up to 70 were achieved. In addition, superhydrophobicity and superior antifogging characteristics enabled the retention of optical properties even in wet and humid conditions, suggesting reliable optical performance in practical outdoor conditions. We anticipate that these properties could potentially enhance the performance of optoelectronic devices and minimize the influence of in-service conditions. Additionally, as our technique is solely nanoimprinting-based, it may enable scalable and high-throughput fabrication of multiscale ommatidial arrays. PMID:25634665

  11. Thermophysical property calculation of core melt diluted by oxide sacrificial material

    International Nuclear Information System (INIS)

    Diluting the core melt with oxide sacrificial material (OSM) during in-vessel retention (IVR) is a newly proposed severe-accident-management strategy of advanced LWR. When severe accident occurs, the OSM is melted by the relocated core melt. resulting in the formation of a ternary liquid mixture of core melt and OSM in the corium. To select OSM and evaluate the heat flux on the vessel outer surface, and to assess the feasibility of the dilution design scheme, the thermophysical properties of the formed multi-component mixture should be obtained first. In this paper, the thermophysical properties of Fe3O4, TiO2 and Al2O3 were compared. Density, specific heat, thermal conductivity and viscosity of the molten ternary mixture UO2-ZrO2-OSM were also calculated. The results show that to ensure the inverse stratification to occur, implying that the oxide layer locates on top of the metallic layer, the required minimum mass of Fe3O4 should be larger than that of TiO2 and Al2O3. The specific heat and thermal conductivity of the ternary mixture increase with OSM mass, while the viscosity decreases as the mass of OSM increases. Moreover at a given temperature, the molten mixture with a lower melting point also has a smaller viscosity. (authors)

  12. Rolled-Up Nanotech: Illumination-Controlled Hydrofluoric Acid Etching of AlAs Sacrificial Layers

    Directory of Open Access Journals (Sweden)

    Costescu Ruxandra

    2009-01-01

    Full Text Available Abstract The effect of illumination on the hydrofluoric acid etching of AlAs sacrificial layers with systematically varied thicknesses in order to release and roll up InGaAs/GaAs bilayers was studied. For thicknesses of AlAs below 10 nm, there were two etching regimes for the area under illumination: one at low illumination intensities, in which the etching and releasing proceeds as expected and one at higher intensities in which the etching and any releasing are completely suppressed. The etch suppression area is well defined by the illumination spot, a feature that can be used to create heterogeneously etched regions with a high degree of control, shown here on patterned samples. Together with the studied self-limitation effect, the technique offers a way to determine the position of rolled-up micro- and nanotubes independently from the predefined lithographic pattern.

  13. Rolled-Up Nanotech: Illumination-Controlled Hydrofluoric Acid Etching of AlAs Sacrificial Layers

    Science.gov (United States)

    Costescu, Ruxandra M.; Deneke, Christoph; Thurmer, Dominic J.; Schmidt, Oliver G.

    2009-12-01

    The effect of illumination on the hydrofluoric acid etching of AlAs sacrificial layers with systematically varied thicknesses in order to release and roll up InGaAs/GaAs bilayers was studied. For thicknesses of AlAs below 10 nm, there were two etching regimes for the area under illumination: one at low illumination intensities, in which the etching and releasing proceeds as expected and one at higher intensities in which the etching and any releasing are completely suppressed. The etch suppression area is well defined by the illumination spot, a feature that can be used to create heterogeneously etched regions with a high degree of control, shown here on patterned samples. Together with the studied self-limitation effect, the technique offers a way to determine the position of rolled-up micro- and nanotubes independently from the predefined lithographic pattern.

  14. Layered materials

    Science.gov (United States)

    Johnson, David; Clarke, Simon; Wiley, John; Koumoto, Kunihito

    2014-06-01

    Layered compounds, materials with a large anisotropy to their bonding, electrical and/or magnetic properties, have been important in the development of solid state chemistry, physics and engineering applications. Layered materials were the initial test bed where chemists developed intercalation chemistry that evolved into the field of topochemical reactions where researchers are able to perform sequential steps to arrive at kinetically stable products that cannot be directly prepared by other approaches. Physicists have used layered compounds to discover and understand novel phenomena made more apparent through reduced dimensionality. The discovery of charge and spin density waves and more recently the remarkable discovery in condensed matter physics of the two-dimensional topological insulating state were discovered in two-dimensional materials. The understanding developed in two-dimensional materials enabled subsequent extension of these and other phenomena into three-dimensional materials. Layered compounds have also been used in many technologies as engineers and scientists used their unique properties to solve challenging technical problems (low temperature ion conduction for batteries, easy shear planes for lubrication in vacuum, edge decorated catalyst sites for catalytic removal of sulfur from oil, etc). The articles that are published in this issue provide an excellent overview of the spectrum of activities that are being pursued, as well as an introduction to some of the most established achievements in the field. Clusters of papers discussing thermoelectric properties, electronic structure and transport properties, growth of single two-dimensional layers, intercalation and more extensive topochemical reactions and the interleaving of two structures to form new materials highlight the breadth of current research in this area. These papers will hopefully serve as a useful guideline for the interested reader to different important aspects in this field and an overview of current areas of research interest.

  15. Generation of cavities in silicon wafers by laser ablation using silicon nitride as sacrificial layer

    Energy Technology Data Exchange (ETDEWEB)

    Lerner, B., E-mail: blerner@cnea.gov.ar [Grupo MEMS, Comision Nacional de Energia Atomica, Buenos Aires (Argentina); Perez, M.S.; Toro, C.; Lasorsa, C.; Rinaldi, C.A.; Boselli, A.; Lamagna, A. [Grupo MEMS, Comision Nacional de Energia Atomica, Buenos Aires (Argentina)

    2012-01-15

    Throughout this investigation, experiments on laser ablation with silicon (Si) wafers have been performed using silicon nitride (Si{sub 3}N{sub 4}) as a sacrificial layer to find the optimal fluence capable of removing the Si{sub 3}N{sub 4}, which allows the subsequent anisotropic etching in Si with potassium hydroxide. As a result, an alternative to the traditional micromachining techniques that require more steps and processing times has been introduced. The effect of the pulse numbers on Si wafers has been studied and it has been observed that when increasing the pulse numbers at the same fluence, the capacity of the pyramidal cavity formed was greater than using only one pulse at higher fluences. Microcavities were performed with a floating Si{sub 3}N{sub 4} layer. This happens to be very useful for the development of drug delivery systems and the manufacture of microarrays. Microcavities were also used as masters for the fabrication of microionizers in polydimethyl siloxane (PDMS).

  16. Using top graphene layer as sacrificial protection during dielectric atomic layer deposition

    OpenAIRE

    Tang, Xiaohui; Reckinger, Nicolas; Poncelet, Olivier; Louette, Pierre; Colomer, Jean-Franois; Raskin, Jean-Pierre; Hackens, Benoit; Francis, Laurent A.

    2014-01-01

    We investigate the structural damage of graphene underlying dielectrics (HfO2 and Al2O3) by remote plasma-enhanced atomic layer deposition (PE-ALD). Dielectric film is grown on bilayer graphene without inducing significant damage to the bottom graphene layer. Based on Raman spectra, we demonstrate that the bottom graphene layer has the salient features of single layer graphene. During the initial half-cycle PE-ALD, the upper graphene layer reacts with the metal precursor, fo...

  17. Evaluation of Ablation rate by the change of Sacrificial Material for PECS in EU-APR

    International Nuclear Information System (INIS)

    EU-APR, modified and improved from its original design of APR1400, has been developed to comply with European Utility Requirements (EUR) and nuclear design requirements of the European countries. In EU-APR, Severe Accident Mitigation Systems are dedicated to providing an independent defense line from that of Engineered Safety Feature (ESF) and Diverse Safety Feature (DSF). They consist of Emergency Reactor Depressurization System (ERDS), Passive Ex-vessel corium retaining and Cooling System (PECS), Severe Accident Containment Spray System (SACSS), Hydrogen Mitigation System (HMS) and Containment Filtered Vent System (CFVS). The PECS, so called core catcher, was introduced to prevent the Molten Core Concrete Interaction (MCCI) after Reactor Vessel (RV) failure. The PECS has experienced a lot of changes from its original design. Recently, the most significant change was that as a SM, limestone concrete is installed on PECS's body wall instead of previous sacrificial material rich in Fe2O3. The main reason of this design change is to overcome the issue that the sacrificial material is ablated rather too fast when reacting with corium that contains a large fraction of Zr metal. Other changes in the geometry of PECS's wall and downcomer design are considered as minor ones. In this paper, the comparison of ablation rates between previous SM and limestone concrete is carried out using MAAP5 code with respective MCCI model according to the material. In this paper, major improvements of MAAP5 model for PECS in EU-APR are presented and the evaluation of ablation rate for the previous SM model and the new LC model is carried out by means of ablation depths with LBLOCA sequence. Two models have respective unique ablation process. The ablation of LC model proceeds at a constant rate regardless of water while the ablation of SM model proceeds at a faster rate before the arrival of cooling water for corium and SM mixture. The change of sacrificial material also takes advantages of the high gaseous content, high melting temperature and latent heat of ablation of limestone concrete. It means that the corium may be stabilized with limited concrete ablation depth so that the amount of sacrificial material to be installed on PECS can be reduced in case of using limestone concrete. In the near future, a study will be carried out to derive a 3-dimensional flux distribution based on the result of MAAP5 analysis for PECS in EU-APR

  18. UV-Enhanced Sacrificial Layer Stabilised Graphene Oxide Hollow Fibre Membranes for Nanofiltration.

    Science.gov (United States)

    Chong, J Y; Aba, N F D; Wang, B; Mattevi, C; Li, K

    2015-01-01

    Graphene oxide (GO) membranes have demonstrated great potential in gas separation and liquid filtration. For upscale applications, GO membranes in a hollow fibre geometry are of particular interest due to the high-efficiency and easy-assembly features at module level. However, GO membranes were found unstable in dry state on ceramic hollow fibre substrates, mainly due to the drying-related shrinkage, which has limited the applications and post-treatments of GO membranes. We demonstrate here that GO hollow fibre membranes can be stabilised by using a porous poly(methyl methacrylate) (PMMA) sacrificial layer, which creates a space between the hollow fibre substrate and the GO membrane thus allowing stress-free shrinkage. Defect-free GO hollow fibre membrane was successfully determined and the membrane was stable in a long term (1200?hours) gas-tight stability test. Post-treatment of the GO membranes with UV light was also successfully accomplished in air, which induced the creation of controlled microstructural defects in the membrane and increased the roughness factor of the membrane surface. The permeability of the UV-treated GO membranes was greatly enhanced from 0.07 to 2.8?L m(-2) h(-1) bar(-1) for water, and 0.14 to 7.5?L m(-2) h(-1) bar(-1) for acetone, with an unchanged low molecular weight cut off (~250?Da). PMID:26527173

  19. UV-Enhanced Sacrificial Layer Stabilised Graphene Oxide Hollow Fibre Membranes for Nanofiltration

    Science.gov (United States)

    Chong, J. Y.; Aba, N. F. D.; Wang, B.; Mattevi, C.; Li, K.

    2015-11-01

    Graphene oxide (GO) membranes have demonstrated great potential in gas separation and liquid filtration. For upscale applications, GO membranes in a hollow fibre geometry are of particular interest due to the high-efficiency and easy-assembly features at module level. However, GO membranes were found unstable in dry state on ceramic hollow fibre substrates, mainly due to the drying-related shrinkage, which has limited the applications and post-treatments of GO membranes. We demonstrate here that GO hollow fibre membranes can be stabilised by using a porous poly(methyl methacrylate) (PMMA) sacrificial layer, which creates a space between the hollow fibre substrate and the GO membrane thus allowing stress-free shrinkage. Defect-free GO hollow fibre membrane was successfully determined and the membrane was stable in a long term (1200?hours) gas-tight stability test. Post-treatment of the GO membranes with UV light was also successfully accomplished in air, which induced the creation of controlled microstructural defects in the membrane and increased the roughness factor of the membrane surface. The permeability of the UV-treated GO membranes was greatly enhanced from 0.07 to 2.8?L m?2 h?1 bar?1 for water, and 0.14 to 7.5?L m?2 h?1 bar?1 for acetone, with an unchanged low molecular weight cut off (~250?Da).

  20. Fabrication of low-temperature co-fired ceramics micro-fluidic devices using sacrificial carbon layers

    OpenAIRE

    Birol, Hansu; Maeder, Thomas; Jacq, Caroline; Straessler, Sigfrid; Ryser, Peter

    2005-01-01

    Ease of fabrication and design flexibility are two attractive features of low temperature co-fired ceramics (LTCC) technology for fabrication of complex micro-fluidic devices. Such structures are designed and processed using different shaping methods, the extent and complexity of which depends on the final device specifications (dimensions, mechanical and functional properties). In this work, we propose a sacrificial layer method based on carbon-black paste, which burns out during the LTCC fi...

  1. Screen printing of a capacitive cantilever-based motion sensor on fabric using a novel sacrificial layer process for smart fabric applications

    Science.gov (United States)

    Wei, Yang; Torah, Russel; Yang, Kai; Beeby, Steve; Tudor, John

    2013-07-01

    Free-standing cantilevers have been fabricated by screen printing sacrificial and structural layers onto a standard polyester cotton fabric. By printing additional conductive layers, a complete capacitive motion sensor on fabric using only screen printing has been fabricated. This type of free-standing structure cannot currently be fabricated using conventional fabric manufacturing processes. In addition, compared to conventional smart fabric fabrication processes (e.g. weaving and knitting), screen printing offers the advantages of geometric design flexibility and the ability to simultaneously print multiple devices of the same or different designs. Furthermore, a range of active inks exists from the printed electronics industry which can potentially be applied to create many types of smart fabric. Four cantilevers with different lengths have been printed on fabric using a five-layer structure with a sacrificial material underneath the cantilever. The sacrificial layer is subsequently removed at 160 C for 30 min to achieve a freestanding cantilever above the fabric. Two silver electrodes, one on top of the cantilever and the other on top of the fabric, are used to capacitively detect the movement of the cantilever. In this way, an entirely printed motion sensor is produced on a standard fabric. The motion sensor was initially tested on an electromechanical shaker rig at a low frequency range to examine the linearity and the sensitivity of each design. Then, these sensors were individually attached to a moving human forearm to evaluate more representative results. A commercial accelerometer (Microstrain G-link) was mounted alongside for comparison. The printed sensors have a similar motion response to the commercial accelerometer, demonstrating the potential of a printed smart fabric motion sensor for use in intelligent clothing applications.

  2. Screen printing of a capacitive cantilever-based motion sensor on fabric using a novel sacrificial layer process for smart fabric applications

    International Nuclear Information System (INIS)

    Free-standing cantilevers have been fabricated by screen printing sacrificial and structural layers onto a standard polyester cotton fabric. By printing additional conductive layers, a complete capacitive motion sensor on fabric using only screen printing has been fabricated. This type of free-standing structure cannot currently be fabricated using conventional fabric manufacturing processes. In addition, compared to conventional smart fabric fabrication processes (e.g. weaving and knitting), screen printing offers the advantages of geometric design flexibility and the ability to simultaneously print multiple devices of the same or different designs. Furthermore, a range of active inks exists from the printed electronics industry which can potentially be applied to create many types of smart fabric. Four cantilevers with different lengths have been printed on fabric using a five-layer structure with a sacrificial material underneath the cantilever. The sacrificial layer is subsequently removed at 160 C for 30 min to achieve a freestanding cantilever above the fabric. Two silver electrodes, one on top of the cantilever and the other on top of the fabric, are used to capacitively detect the movement of the cantilever. In this way, an entirely printed motion sensor is produced on a standard fabric. The motion sensor was initially tested on an electromechanical shaker rig at a low frequency range to examine the linearity and the sensitivity of each design. Then, these sensors were individually attached to a moving human forearm to evaluate more representative results. A commercial accelerometer (Microstrain G-link) was mounted alongside for comparison. The printed sensors have a similar motion response to the commercial accelerometer, demonstrating the potential of a printed smart fabric motion sensor for use in intelligent clothing applications. (paper)

  3. Creation of freestanding wrinkled nano-films with desired deformation properties by controlling the surface morphology of a sacrificial layer

    Science.gov (United States)

    Hirakata, Hiroyuki; Maruyama, Tomohiro; Yonezu, Akio; Minoshima, Kohji

    2013-05-01

    Various wrinkle patterns can be formed due to the buckling of a stiff thin film on a compliant substrate. However, most wrinkled films previously reported were fixed on a large deformable substrate and thereby the potential deformability of the film was mechanically constrained by the substrate. In this study, we developed a technique for forming various wrinkled structures on the surface of a sacrificial resin layer. Since the sacrificial layer can be subsequently removed with a solvent, freestanding wrinkled films are created using the sacrificial layer. We found that a wrinkled structure is formed on the surface of the layer by applying a compressive strain to the resin layer at the appropriate moment during the hardening process. The wrinkle pattern depends on the curing time and the timing of the straining in two in-plane orthogonal directions. In addition to conventional stripe and labyrinth patterns by simple uniaxial and equi-biaxial strains, respectively, it was found that independent biaxial strains induce interesting structures, such as an orthogonally ordered wrinkle pattern and a nonsymmetrical buckling structure, in which the stripe array produced by the first straining remains and many finer wrinkles appear in each stripe by the second straining in the orthogonal direction. We conducted tensile experiments for 300-nm-thick freestanding Cu films having these wrinkled structures. The wrinkled nano-films have a variety of mechanical properties: the stripe structure has extremely high deformability (more than 10% strain) and reversibility, the labyrinth structure shows planar isotropic deformation, and the nonsymmetrical buckling structure has an anisotropic modulus and strength. Finite element analysis on the wrinkle structures revealed that the local stress concentration dominates the fracture limits.

  4. A potential method of containing rockburst damage and enhancing safety using a sacrificial layer

    Scientific Electronic Library Online (English)

    T.R., Stacey; E., Rojas.

    Full Text Available Rockbursts continue to be a scourge in the mining industry, being responsible for accidents and damage to mining excavations. Although the problem has been present for more than a century, and although much research has been carried out, a solution is still elusive. Determination of, firstly, the de [...] mand on the support system imposed in the rockburst and, secondly, the capacity of the support system, cannot be carried out with any confidence, and therefore rockburst support cannot be designed using a conventional design approach. In contrast with the conventional approach, observations of rockburst damage in a mine have revealed a possible alternative approach to rockburst support - sacrificial support. It was observed, in rockburst events, that a support system consisting of concrete panels restrained by grouted cables was destroyed, and the concrete panels were ejected. However, the rock behind the panels remained apparently undamaged and in place. This behaviour reignited the concept of sacrificial support, conceived more than 20 years ago, and which is described in this paper. The remedial solution implemented on the mine, involving cables wrapped over the panels and retained by grouting into boreholes, has been subjected to rockburst loading and has confirmed the validity of the sacrificial support concept. The concept of sacrificial support may be controversial, but is deliberately presented here with the aim of generating discussions and contributions, and with the ultimate aim of improving safety and reducing rockburst damage in mines.

  5. Heat Transfer Calculation of core melt diluted by oxide sacrificial material during in-vessel retention

    International Nuclear Information System (INIS)

    Diluting the core melt with oxide sacrificial material (OSM) during in-vessel retention (IVR) is a newly proposed severe-accident-management strategy of advanced LWRs. When severe accident occurs, the relocated core melt is diluted by OSM, resulting in the inverse stratification of melt pool configuration. Therefore, the researches on the calculations of heat transfer of melt pool are essential to optimize the component of OSM and evaluate the effectiveness of the strategy. The heat flux on the vessel outer surface after diluting the core melt with Fe3O4, TiO2 and Al2O3, respectively was calculated. The results show that the structure of upper plenum will melt due to the intense heat radiation after OSM is used. The maximum heat flux on the vessel outer surface reduces with the increase of OSM. When the volume of the OSM ceramics reaches 15 m3, the reactor vessel length should be increased by approximately 2 m. In this case, the heat flux reduces about 45% compared to the reactors without OSM. Moreover, the reduction of heat flux is most pronounced as Fe3O4 is used. In addition, the melting point of UO2-ZrO2-OSM affects the appearance of a crust on the surface of the oxide mixture, which in turn influences the maximum heat flux on the vessel outer surface. (authors)

  6. BEOL compatible high tunnel magneto resistance perpendicular magnetic tunnel junctions using a sacrificial Mg layer as CoFeB free layer cap

    Science.gov (United States)

    Swerts, J.; Mertens, S.; Lin, T.; Couet, S.; Tomczak, Y.; Sankaran, K.; Pourtois, G.; Kim, W.; Meersschaut, J.; Souriau, L.; Radisic, D.; Van Elshocht, S.; Kar, G.; Furnemont, A.

    2015-06-01

    Perpendicularly magnetized MgO-based tunnel junctions are envisaged for future generation spin-torque transfer magnetoresistive random access memory devices. Achieving a high tunnel magneto resistance and preserving it together with the perpendicular magnetic anisotropy during BEOL CMOS processing are key challenges to overcome. The industry standard technique to deposit the CoFeB/MgO/CoFeB tunnel junctions is physical vapor deposition. In this letter, we report on the use of an ultrathin Mg layer as free layer cap to protect the CoFeB free layer from sputtering induced damage during the Ta electrode deposition. When Ta is deposited directly on CoFeB, a fraction of the surface of the CoFeB is sputtered even when Ta is deposited with very low deposition rates. When depositing a thin Mg layer prior to Ta deposition, the sputtering of CoFeB is prevented. The ultra-thin Mg layer is sputtered completely after Ta deposition. Therefore, the Mg acts as a sacrificial layer that protects the CoFeB from sputter-induced damage during the Ta deposition. The Ta-capped CoFeB free layer using the sacrificial Mg interlayer has significantly better electrical and magnetic properties than the equivalent stack without protective layer. We demonstrate a tunnel magneto resistance increase up to 30% in bottom pinned magnetic tunnel junctions and tunnel magneto resistance values of 160% at resistance area product of 5 ?.?m2. Moreover, the free layer maintains perpendicular magnetic anisotropy after 400 C annealing.

  7. Silica sacrificial layer-assisted in-plane incorporation of Au nanoparticles into mesoporous titania thin films through different reduction methods.

    Science.gov (United States)

    Liang, Chih-Peng; Yamauchi, Yusuke; Liu, Chia-Hung; Wu, Kevin C-W

    2013-06-28

    This study focuses on the incorporation of gold nanoparticles (Au NPs) into our previously synthesized mesoporous titania thin films consisting of titania nanopillars and inverse mesospace (C. W. Wu, T. Ohsuna, M. Kuwabara and K. Kuroda, J. Am. Chem. Soc., 2006, 128, 4544-4545, denoted as MTTFs). Recently, mesoporous titania materials doped with noble metals such as gold have attracted considerable attention because noble metals can enhance the efficiency of mesoporous titania-based devices. In this research, we attempted to use four different reduction methods (i.e., thermal treatment, photo irradiation, liquid immersion, and vapor contacting) to introduce gold nanoparticles (Au NPs) into MTTFs. The synthesized Au@MTTFs were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). We further systematically investigated the formation mechanism of gold nanoparticles on the external and internal surfaces of the MTTFs. With the assistance of a silica sacrificial layer, well-dispersed Au NPs with sizes of 4.1 nm were obtained inside the MTTF by photo irradiation. The synthesized Au@MTTF materials show great potential in various photo-electronic and photo-catalytic applications. PMID:23633080

  8. Platinum ion implantation into single crystal zirconia with a carbon sacrificial layer on the surface

    International Nuclear Information System (INIS)

    Single crystal samples of (100) oriented yttria stabilized cubic zirconia are implanted with Pt ions to doses up to 6 x 1017/cm2. The previous studies showed that the retained Pt dose was too small due to the sputter limit. To overcome this problem, a C film was deposited on the surface of some samples before implantation. The implanted samples were annealed isothermally in air at 400--1,200 C, and were analyzed with RBS-C and TEM. The C-layer has been found to be very effective for protecting the sample surface from sputtering and thus increasing the Pt concentration by a factor of two, up to 33 mol.% Pt. The as-implanted Pt was nonsubstitutional. After annealing at 1,200 C for 1 h, Pt diffused to large depths, and showed a substitutional fraction of about 23%. The detailed TEM measurements on the microstructure and damage of the implanted layer show that after annealing at these temperatures the recovery of ion damage is incomplete. Pt atoms undergo substantial migration concurrently. The Pt at first dissolves in the matrix (though not substitutionally), diffuses and precipitates again at high temperature

  9. Fabrication of 3-nm-thick Si3N4 membranes for solid-state nanopores using the poly-Si sacrificial layer process

    Science.gov (United States)

    Yanagi, Itaru; Ishida, Takeshi; Fujisaki, Koji; Takeda, Ken-Ichi

    2015-10-01

    To improve the spatial resolution of solid-state nanopores, thinning the membrane is a very important issue. The most commonly used membrane material for solid-state nanopores is silicon nitride (Si3N4). However, until now, stable wafer-scale fabrication of Si3N4 membranes with a thickness of less than 5?nm has not been reported, although a further reduction in thickness is desired to improve spatial resolution. In the present study, to fabricate thinner Si3N4 membranes with a thickness of less than 5?nm in a wafer, a new fabrication process that employs a polycrystalline-Si (poly-Si) sacrificial layer was developed. This process enables the stable fabrication of Si3N4 membranes with thicknesses of 3?nm. Nanopores were fabricated in the membrane using a transmission electron microscope (TEM) beam. Based on the relationship between the ionic current through the nanopores and their diameter, the effective thickness of the nanopores was estimated to range from 0.6 to 2.2?nm. Moreover, DNA translocation through the nanopores was observed.

  10. Buckle-driven delamination of hydrophobic micro-, nano-, and heterostructured membranes without a sacrificial layer

    Science.gov (United States)

    Larsen, George K.; Zhao, Yiping

    2013-10-01

    A fabrication method, based on thin film buckling, is demonstrated to form unique membranes that can be used for applications in optics and biosensing. This method should be applicable to a variety of material systems, which, along with its simplicity and compatibility with different film architectures, allows for widespread implementation.A fabrication method, based on thin film buckling, is demonstrated to form unique membranes that can be used for applications in optics and biosensing. This method should be applicable to a variety of material systems, which, along with its simplicity and compatibility with different film architectures, allows for widespread implementation. Electronic supplementary information (ESI) available: Monolayer characterization and details; morphological parameters of the membranes; diffraction pattern images; rigorous coupled wave analysis; pattern transfer fidelity; experimental details. See DOI: 10.1039/c3nr03933a

  11. The case for using a sacrificial layer of absorbent insulation in the design of flat and low-sloped roofing

    Science.gov (United States)

    Stockton, Gregory R.

    2013-05-01

    Beginning about twenty-five years ago, there was a marked increase in the number of single-ply membrane roof designs used to cover and waterproof flat and low-sloped building roofs. Over the past ten years, there has been a substantial increase in the number of installations of white and more reflective single-ply roof systems, mostly using high density cellular foam insulation in the substrate for insulation. A major factor in the increase in the popularity of these highly insulated and more reflective roof systems is the fact that many governments began offering incentives for building owners to use reflective coverings and better insulated roofs. Now, owing to the energy efficient requirements for the design and construction of new buildings put forth in ASHRAE Standard 90.1, "Energy Standard for Buildings Except Low-Rise Residential Buildings" and the world's apparent desire to be "green" (or at least appear to be), more and more roof designs will include these reflective single-ply membranes, which use the cellular foam insulation boards to meet these requirements. Using a lower density traditional insulation will mean that the roof will have to be very thick to comply, increasing the costs of installation. High density cellular foams do not absorb water until time, vapor pressure drive, UV and thermal shock break down the foam and it becomes more absorbent. This could be 5-7 years or longer, depending on the roof construction and other factors. This means that any water that enters the roof through a breach (leak) in the membrane goes straight into the building. This is not a good consequence since the failure mode of any roof is water entering the building. Keeping the water out of the building is the purpose of the waterproofing layer. This paper reviews the techniques of moisture testing on building roofs and infrared (IR) thermography, and puts forth the idea and reasoning behind having a sacrificial layer of very absorbent insulation installed in every flat and low-sloped roof so that when a breach occurs, it can easily be found, documented and repaired during an annual infrared inspection; as IR is an effective predictive maintenance technique and condition monitoring best practice for roof maintenance.

  12. Comparison of solvent and sacrificial volume-material-based lamination processes of low-temperature co-fired ceramics tapes

    International Nuclear Information System (INIS)

    The lamination process determines the quality of low temperature co-fired ceramics (LTCC) based spatial structures. This paper compares two methods of the microchannel fabrication process in zero-shrinkage LTCC substrates. The first one is based on a two-step lamination process and uses various sacrificial volume materials (SVM). The second one is based on the cold chemical lamination (CCL) process. On the one hand, the SVM gives the possibility of decreasing the deformation of the three-dimensional (3D) structures during the lamination process. The channel volume is filled with a special fugitive material. It protects the spatial structure from deformation during lamination, and evaporates completely during the co-firing process. The bonding quality and strength depend strongly on the fugitive phase type. On the other hand, the CCL is a solvent-based method. It is another alternative for bonding of green ceramic tapes. A special liquid agent is screen printed on the green tape, which melts the tape surface. Then the tapes are stacked and compressed at room temperature by a printing roll. The influence of each method on the microchannel geometry is analyzed in this paper. The resulting structures' bonding quality and mechanical properties are examined by a scanning electron microscope (SEM)

  13. A concave-patterned TiN/PECVD-Si3N4?/TiN diaphragm MEMS acoustic sensor based on a polyimide sacrificial layer

    Science.gov (United States)

    Lee, Jaewoo; Jeon, J. H.; Je, C. H.; Kim, Y.-G.; Lee, S. Q.; Yang, W. S.; Lee, J. S.; Lee, S.-G.

    2015-12-01

    In this paper, we present a concave-patterned TiN/PECVD-Si3N4?/TiN diaphragm micro-electro-mechanical system (MEMS) acoustic sensor based on a polyimide sacrificial layer. The use of the spin-coated polyimide eliminates the additional Al pad process of conventional device fabrication due to simple O2 ashing to release the sacrificial layer, simplifying the photolithography process. Also, to adjust the acoustic sensor for a bottom-ported package, its diaphragm was implemented to be placed over the back-plate. The TiN/PECVD-Si3N4/TiN multi-layer diaphragm was formed with the stress controllability of PECVD-Si3N4 from???162?MPa to??+109?MPa. Furthermore, a parallel-plate capacitance model on the basis of an approximately linearized electric field method (ALEM) is proposed to evaluate the capacitance of two plates. The modelled capacitance showed less than 3.7% error in FEM simulation, demonstrating the validity of the proposed model. At a zero-bias voltage, the effective intrinsic and parasitic capacitances in the active area were 1.656 pF and 0.388 pF, respectively. Moreover, with a pull-in analytical model by using ALEM, the effective tensile stress for the diaphragm was extracted to??+31.5?MPa, where the pull-in voltage was 10.7?V. In succession, the dynamic response for the open-circuit sensitivity was modelled with an equivalent circuit model based on lumped parameters. The measured open-circuit sensitivity of???45.1 dBV Pa?1 at 1?kHz with a bias of 9.6?V was only slightly different from the modelled sensitivity of???45.0 dBV Pa?1. Thus, these results demonstrate that the proposed sensor is suitable for a front-end voice capture module.

  14. Structuration of thin bridge and cantilever structures in thick-film technology using mineral sacrificial materials

    OpenAIRE

    Maeder, Thomas; Jacq, Caroline; Fournier, Yannick; Hraiz, Wassim; Ryser, Peter

    2009-01-01

    Thick-film and LTCC (Low Temperature Cofired Ceramic) technologies find increasing use in meso-scale sensors, actuators and related devices that feature excellent dimensional, thermal and chemical stability at moderate cost. While several materials and processes allow fabrication of structures such as channels, membranes and relatively short bridges, obtaining slender bridges and cantilevers with good shape control for applications such as microforce sensors has hitherto remained ...

  15. High-reflectivity GaN/air vertical distributed Bragg reflectors fabricated by wet etching of sacrificial AlInN layers

    International Nuclear Information System (INIS)

    Microstructures containing GaN/air distributed Bragg reflector (DBR) regions were fabricated by a selective wet etch to remove sacrificial AlInN layers from GaNAlInN multilayers. The epitaxial multilayers were grown on free-standing GaN substrates, and contained AlInN essentially lattice matched with GaN in order to minimize strain. Two geometries were defined for study by standard lithographic techniques and dry etching: cylindrical pillars and doubly anchored rectangular bridges. Microreflectivity spectra were recorded from the air-gap DBRs, and indicated peak reflectivities exceeding 70% for a typical 3-period microbridge. These values are likely to be limited by the small scale of the features in comparison with the measurement spot. The stopband in this case was centred at 409 nm, and the reflectivity exceeded 90% of the maximum over 73 nm. Simulations of reflectance spectra, including iterations to layer thicknesses, gave insight into the tolerances achievable in processing, in particular indicating bounds on the parasitic removal of GaN layers during wet etching. Air-gap nitride DBRs as described can be further developed in various ways, including adaptation for electrostatic tuning, incorporation into microcavities, and integration with active emitters. (rapid communication)

  16. Manufacture of micro-electro-mechanical-system using sacrificial layer made of silicon, useful for micro-electro-mechanical-system device architecture, e.g. radio-frequency capacitive switch and current switch

    OpenAIRE

    IONESCU, M.A.; FLUCKIGER, PH; HIBERT, C; FRITSCHI, R; POTT, V

    2002-01-01

    NOVELTY - A micro-electro-mechanical-system (MEMS) is manufactured by the use of a sacrificial layer that is made of silicon. USE - The invention is used in surface micromachining for the manufacture of a MEMS containing a suspended metal layer or MEMS device architecture. MEMS device is a suspended gate metal oxide semiconductor field effect transistor (SG-MOSFET). It is used as radio-frequency capacitive switch, current switch, radio-frequency tuneable capacitor, magnetic field sensor, acce...

  17. Hot sodium-triggered thermo-chemical degradation of concrete aggregates in the sodium resistant sacrificial layers of fast breeder reactors

    International Nuclear Information System (INIS)

    Highlights: Concrete aggregates were exposed to liquid sodium exposure at 550 C. Thermal and chemical effects were studied using megascopic and micro-analytical techniques. Aggregates underwent significant thermo-chemical degradation upon exposure. Limestone found more suitable for sodium environment than siliceous aggregate. - Abstract: Sodium is used as an efficient coolant in fast breeder reactor (FBR) for extracting nuclear heat from its high power density core to steam generator, to produce electricity. Accidentally spilled Sodium at elevated temperatures of 550 C or above may interact with concrete leading to its deterioration. A sacrificial concrete layer is provided on the structural concrete to mitigate the harmful impacts of these interactions. Locally available crushed rocks like limestone and granite are employed as aggregates in sacrificial and structural concrete respectively. Rocks are naturally occurring multi-mineral and multiphase inorganic systems of the earth. Aggregates are the main constituents of concrete accounting for 7080% of its mass. In this paper, an attempt is made to study the physico-chemical modifications that may occur in the aggregates during the interactions between liquid sodium and the aggregates of concrete. The experimental strategy consists of heating of granite, limestone and river sand aggregates at 550 C for 30 min and further treating them with 1 Normal aqueous solution of NaOH, to differentiate thermal and chemical effects. Furthermore, sodium-aggregate interaction study at 550 C was conducted to characterize the combined effects of heat and sodium. Siliceous aggregates (granite and river sand) were found to be easily attacked by ferric oxidation during heating in air and also subjected to rapid chemical reactions with liquid NaOH, producing mineral phases of sodium silicate, sodium orthosilicates, calcium orthosilicates and sodium carbonates. Initiation and propagation of cracking in the siliceous aggregates are sustained due to differential thermal expansion of minerals and chemical invasion of inter-granular structures. Limestone, on the other hand, was mostly stable, and its thermal performance was affected by the fraction of deleterious accessory minerals present in it. Combined action of corrosive NaOH and heat induced cracks in hot sodium environment at 550 C may lead to more drastic degradation of concrete with siliceous aggregate than with limestone aggregate

  18. Building biomedical materials layer-by-layer

    Directory of Open Access Journals (Sweden)

    Paula T. Hammond

    2012-05-01

    Full Text Available In this materials perspective, the promise of water based layer-by-layer (LbL assembly as a means of generating drug-releasing surfaces for biomedical applications, from small molecule therapeutics to biologic drugs and nucleic acids, is examined. Specific advantages of the use of LbL assembly versus traditional polymeric blend encapsulation are discussed. Examples are provided to present potential new directions. Translational opportunities are discussed to examine the impact and potential for true biomedical translation using rapid assembly methods, and applications are discussed with high need and medical return.

  19. CMUTs with High-K Atomic Layer Deposition Dielectric Material Insulation Layer

    Science.gov (United States)

    Xu, Toby; Tekes, Coskun; Degertekin, F. Levent

    2014-01-01

    Use of high-? dielectric, atomic layer deposition (ALD) materials as an insulation layer material for capacitive micromachined ultrasonic transducers (CMUTs) is investigated. The effect of insulation layer material and thickness on CMUT performance is evaluated using a simple parallel plate model. The model shows that both high dielectric constant and the electrical breakdown strength are important for the dielectric material, and significant performance improvement can be achieved, especially as the vacuum gap thickness is reduced. In particular, ALD hafnium oxide (HfO2) is evaluated and used as an improvement over plasma-enhanced chemical vapor deposition (PECVD) silicon nitride (SixNy) for CMUTs fabricated by a low-temperature, complementary metal oxide semiconductor transistor-compatible, sacrificial release method. Relevant properties of ALD HfO2 such as dielectric constant and breakdown strength are characterized to further guide CMUT design. Experiments are performed on parallel fabricated test CMUTs with 50-nm gap and 16.5-MHz center frequency to measure and compare pressure output and receive sensitivity for 200-nm PECVD SixNy and 100-nm HfO2 insulation layers. Results for this particular design show a 6-dB improvement in receiver output with the collapse voltage reduced by one-half; while in transmit mode, half the input voltage is needed to achieve the same maximum output pressure. PMID:25474786

  20. CMUTs with high-K atomic layer deposition dielectric material insulation layer.

    Science.gov (United States)

    Xu, Toby; Tekes, Coskun; Degertekin, F

    2014-12-01

    Use of high-? dielectric, atomic layer deposition (ALD) materials as an insulation layer material for capacitive micromachined ultrasonic transducers (CMUTs) is investigated. The effect of insulation layer material and thickness on CMUT performance is evaluated using a simple parallel plate model. The model shows that both high dielectric constant and the electrical breakdown strength are important for the dielectric material, and significant performance improvement can be achieved, especially as the vacuum gap thickness is reduced. In particular, ALD hafnium oxide (HfO2) is evaluated and used as an improvement over plasma-enhanced chemical vapor deposition (PECVD) silicon nitride (Six)Ny)) for CMUTs fabricated by a low-temperature, complementary metal oxide semiconductor transistor-compatible, sacrificial release method. Relevant properties of ALD HfO2) such as dielectric constant and breakdown strength are characterized to further guide CMUT design. Experiments are performed on parallel fabricated test CMUTs with 50-nm gap and 16.5-MHz center frequency to measure and compare pressure output and receive sensitivity for 200-nm PECVD Six)Ny) and 100-nm HfO2) insulation layers. Results for this particular design show a 6-dB improvement in receiver output with the collapse voltage reduced by one-half; while in transmit mode, half the input voltage is needed to achieve the same maximum output pressure. PMID:25474786

  1. A sacrificial SU-8 mask for direct metallization on PDMS

    International Nuclear Information System (INIS)

    A new fabrication technology utilizing SU-8 as a sacrificial mask for metallization of the PDMS surface is presented. The sacrificial SU-8 layer process offers superior performance for reliable and repeatable metallization on the PDMS layer. Sacrificial SU-8 masks from 45 m to 250 m thickness are successfully fabricated on the PDMS layer to pattern gold on the PDMS surface. These layers are successfully peeled off from the PDMS surface after a metal deposition step. Metal lines from 10 m to 500 m wide and 1 mm to 50 mm long are successfully patterned and tested. Furthermore, the sacrificial SU-8 mask can be removed within minutes to realize metal patterns on the PDMS surface and does not leave any residue after removal of the SU-8 layer. As this new process is intended for use in fabrication of microfluidic and biomedical microdevices, electrodes of an electro-enzymatic glucose sensor are presented to demonstrate the technology

  2. Liquid phase epitaxy monocrystalline silicon thin film on sacrificial layers for carrying out cheap photovoltaic devices; Croissance de silicium monocristallin en couche mince par epitaxie en phase liquide sur couches sacrificielles pour report sur substrat faible cout pour applications photovoltaiques

    Energy Technology Data Exchange (ETDEWEB)

    Berger, S.

    2003-07-01

    This work deals with the use of sacrificial layers obtained by liquid phase epitaxy for manufacturing solar cells. Three kinds of sacrificial layers are studied: the macroporous silicon or grids, the nano-porous silicon and the layers embrittled by ionic implantation. The macroporous silicon allows to control the porosity and then the embrittlement of the layer. It is easily transferable and detachable. The used substrate is recyclable. The transfer is carried out before the growth. A study on silicon for allowing an electrochemical attack has been carried out. The wished characteristics of the grids have been defined in order to be able to make a growth above it. The transfer, followed by the growth, has been carried out. The orientation of the support being (100), the morphology of the layer is an assembly of pyramids. The adjustment of the parameters allows to improve the coalescence between the pyramids. During this work, a phenomenon has been observed: the consumption of the growth substrate silicon. A study has been carried out on SOI supports for adjusting the growth parameters. In order to decrease the costs, it has been considered to carry out the epitaxy before the transfer. The nano-porous silicon layers have then appeared as the continuity of the study. The characteristics of this porous silicon have been studied to allow the detachment of the epitaxied layer. The layers obtained on the substrate (100) are formed of pyramids whose coalescence depends of the parameters of the epitaxy. On the substrate (111), the layers obtained are continuous and homogeneous and the detachment is carried out. Another solution is to adapt the SMART-CUT ionic implantation technique to the photovoltaic field. (O.M.)

  3. Application of graphite-based sacrificial layers for fabrication of LTCC (low temperature co-fired ceramic) membranes and micro-channels

    OpenAIRE

    Birol, Hansu; Maeder, Thomas; Ryser, Peter

    2007-01-01

    Fabrication of sensors and micro-fluidic structures from low temperature co- fired ceramic (LTCC) sheets is a growing interest in the micro-packaging community. Such devices usually have inner cavities, whose production is quite complicated. The most elegant method to build such structures so far achieved is by a fugitive phase that is introduced into the multilayer and removed during firing. This paper, therefore, is aimed to introduce the graphite-based sacrificial paste developed for ...

  4. Metal-Organic Framework Nanocrystals as Sacrificial Templates for Hollow and Exceptionally Porous Titania and Composite Materials.

    Science.gov (United States)

    Yang, Hui; Kruger, Paul E; Telfer, Shane G

    2015-10-01

    We report a strategy that employs metal-organic framework (MOF) crystals in two roles for the fabrication of hollow nanomaterials. In the first role the MOF crystals provide a template on which a shell of material can be deposited. Etching of the MOF produces a hollow structure with a predetermined size and morphology. In combination with this strategy, the MOF crystals, including guest molecules in their pores, can provide the components of a secondary material that is deposited inside the initially formed shell. We used this approach to develop a straightforward and reproducible method for constructing well-defined, nonspherical hollow and exceptionally porous titania and titania-based composite nanomaterials. Uniform hollow nanostructures of amorphous titania, which assume the cubic or polyhedral shape of the original template, are delivered using nano- and microsized ZIF-8 and ZIF-67 crystal templates. These materials exhibit outstanding textural properties including hierarchical pore structures and BET surface areas of up to 800 m(2)/g. As a proof of principle, we further demonstrate that metal nanoparticles such as Pt nanoparticles, can be encapsulated into the TiO2 shell during the digestion process and used for subsequent heterogeneous catalysis. In addition, we show that the core components of the ZIF nanocrystals, along with their adsorbed guests, can be used as precursors for the formation of secondary materials, following their thermal decomposition, to produce hollow and porous metal sulfide/titania or metal oxide/titania composite nanostructures. PMID:26365676

  5. Application of the GEMINI2 code to Develop the Sacrificial Concrete for the Core-catcher Experiment by KAERI

    International Nuclear Information System (INIS)

    In the late phase of a severe accident, the reactor lower vessel may fail, the hot molten corium discharging into the reactor cavity can threaten the integrity of the containment due to the combustible gas generation, the fission product release and the large amount of steam generation from the MCCI (molten core concrete interaction). Therefore, it is important to make the relocated hot molten corium cool-down in a safe and fast manner. For this purpose, KAERI has proposed a new cooling concept for the corium in a cavity by simultaneously injecting water and non-condensable gas into the nozzles embedded in the concrete basement from the bottom. From the COMET experimental results, the most important condition to achieve a cooling for a melt by a 'bottom injection' will be whether the melt can be changed into a porous structure or not. It means that the phenomena for forming a porous structure by a fuel coolant interaction during a bottom injection are the crucial mechanisms that need to be identified. The possible scenario to form a porous layer may be a 'local pressure build-up' by a strong steam generation. This pressure build-up may propagate and expand in a lateral direction. Also, this steam filled void region may iterate an expansion and shrinkage. In addition, this strong vibration and steaming may produce a porous layer. KAERI is planning to perform a core-catcher experiment for identifying the debris coolability by a bottom injection. To fulfill this experiment successfully, it is necessary to develop sacrificial concrete. The sacrificial concrete can decrease not only the corium temperature but also the viscosity. An enhanced mobility can provide a higher possibility to form a porous layer. The purpose of this study is to elucidate the CaO content in the sacrificial concrete using the GEMINI2 code. Figure 1 is the conceptual picture for the core-catcher experiment. The melt from the termite reactions will be relocated over the sacrificial concrete. The water will be injected from the bottom after the melt has eroded the sacrificial concrete. The purpose of the experiment is to estimate whether a porous layer can be formed or not. The main ingredient of the sacrificial concrete is CaO. The application of the sacrificial concrete can decrease not only the solidus temperature but also the viscosity. If the molten corium has a high solidification temperature, then even a small cooling at the begin of the bottom injection may make the most of the molten material freeze immediately. A lower viscosity can provide more mobility to a molten material. An enhanced mobility and a lowered solidification temperature can provide an enhanced possibility of forming a porous layer. Consequently, the purpose of this study is to elucidate the CaO content for the sacrificial concrete, which can make the solidus and liquidus temperature low using the GEMINI-2 code. This sacrificial concrete will be applied to a test for estimating the corium coolability under a bottom injection based on the new cooling concept developed by KAERI

  6. Surface micromachined PDMS microfluidic devices fabricated using a sacrificial photoresist

    International Nuclear Information System (INIS)

    PDMS is a widely used material for construction of microfluidic devices. The traditional PDMS microfabrication process, although versatile, cannot be used to form microfluidic devices with embedded tall topological features, such as thick-film electrodes and porous reactor beds. This paper presents an elegant surface micromachining process for microfluidic devices that allows complete leak-proof sealing and a conformal contact of the PDMS with tall pre-existing topographical features and demonstrates this approach by embedding 6 m thick Ag/AgCl (high capacity 1680 A s) electrodes inside the microchannels. In this process, thin spin-cast films of the PDMS are used as the structural material and a photoresist is used as the sacrificial material. A crucial parameter, namely adhesion of the spun-cast structural layer to the substrate, was characterized for different pre-polymer ratios using a standard tensile test, and a 1:3 (curing agent:base) combination was found to be the best with a maximum adhesion strength of 7.2 MPa. The elastic property of the PDMS allowed extremely fast release times of ?1 min of the fabricated microchannels. The versatility of this process was demonstrated by the fabrication of a pneumatic microvalve with multi-layered microchannel geometry. The valve closure occurred at 6.37 kPa

  7. Surface micromachined PDMS microfluidic devices fabricated using a sacrificial photoresist

    Science.gov (United States)

    Ganapathy Subramani, Balasubramanian; Selvaganapathy, Ponnambalam Ravi

    2009-01-01

    PDMS is a widely used material for construction of microfluidic devices. The traditional PDMS microfabrication process, although versatile, cannot be used to form microfluidic devices with embedded tall topological features, such as thick-film electrodes and porous reactor beds. This paper presents an elegant surface micromachining process for microfluidic devices that allows complete leak-proof sealing and a conformal contact of the PDMS with tall pre-existing topographical features and demonstrates this approach by embedding 6 m thick Ag/AgCl (high capacity 1680 A s) electrodes inside the microchannels. In this process, thin spin-cast films of the PDMS are used as the structural material and a photoresist is used as the sacrificial material. A crucial parameter, namely adhesion of the spun-cast structural layer to the substrate, was characterized for different pre-polymer ratios using a standard tensile test, and a 1:3 (curing agent:base) combination was found to be the best with a maximum adhesion strength of 7.2 MPa. The elastic property of the PDMS allowed extremely fast release times of ~1 min of the fabricated microchannels. The versatility of this process was demonstrated by the fabrication of a pneumatic microvalve with multi-layered microchannel geometry. The valve closure occurred at 6.37 kPa. Preliminary results of this paper have been presented at the Canadian Workshop on MEMS and Microfluidics, Montral, Canada, August 2007.

  8. Compressive Failure Mechanisms in Layered Materials

    DEFF Research Database (Denmark)

    Srensen, Kim Dalsten

    Two important failure modes in fiber reinforced composite materials in cluding layers and laminates occur under loading conditions dominated by compression in the layer direction. These two distinctly different failure modes are 1. buckling driven delamination 2. failure by strain localization into...

  9. Thin film of Poly(acrylic acid-co-allyl acrylate as a Sacrificial Protective Layer for Hydrophilic Self Cleaning Glass

    Directory of Open Access Journals (Sweden)

    J?nis Lejnieks

    2010-05-01

    Full Text Available Poly(acrylic acid-co-allyl acrylate statistical copolymers were synthesized in a controlled manner in two steps: first tert.butyl acrylate and allyl acrylate were polymerized via atom transfer radical polymerization (ATRP and afterwords the tert.butyl protective groups were removed via hydrolysis. Samples of self cleaning glass (SCG were coated with thin films of poly(acrylic acid-co-allyl acrylate and cross-linked afterwards by UV irradiation (in the presence of a photoinitiator and an accelerator. Solution cast thin films were transparent and homogeneous before and after UV cross-linking. The irradiated samples were found to be hydrophilic (? < 20 and water insoluble. The coating prevented the spontaneous hydrophobization of the SCG by residual silicon exhaled from the sealing material. The TiO2 photocatalyst that covers the glass surface was found to strip the protective coating. The rate of the photooxidation process was measured by IR spectroscopy. The real field performance of the protective coating was also tested.

  10. KAPOOL experiments to simulate molten corium - sacrificial concrete interaction

    International Nuclear Information System (INIS)

    In future Light Water Reactors special devices (core catchers) might be required to prevent containment failure by basement erosion after reactor pressure vessel melt-through during a core meltdown accident. In the planned European Pressurized Reactor (EPR) the core melt is retained in the reactor cavity for ? 1 h to pick up late melts after the failure of the reactor pressure vessel. The reactor cavity is protected by a layer of sacrificial concrete and closed by a melt gate at the bottom towards the spreading compartment. After erosion of the sacrificial concrete and melt-through of the gate the core melt should be distributed homogeneously into the spreading compartment. There the melt is cooled by flooding with water. The knowledge of the sacrificial concrete erosion phase in the reactor cavity is essential for the severe accident assessment. Several KAPOOL experiments have been performed to investigate the erosion of two possible compositions of sacrificial concretes using alumina-iron thermite melts as a simulant for the core melt. Erosion rates as a function of the melt temperature and the inhomogeneity of the melt front are presented in this paper. (authors)

  11. Preface "Layer silicate materials and clays"

    OpenAIRE

    Valdre, G

    2010-01-01

    Abstract Here we report the preface entitled "Layer silicate materials and clays" related to the 14th International Clay Conference, Castellaneta Marina, Italy, June 2009. A special issue of the Philosophical Magazine collects some selected works of Clay Science with the purpose to show the wide range of applications and/or new fields, or recent relevant achievements in traditional, well-established subjects, or prospects of future developments, all related to material scienc...

  12. Layered zeolite materials and methods related thereto

    Science.gov (United States)

    Tsapatsis, Michael; Maheshwari, Sudeep; Bates, Frank S; Koros, William J

    2013-08-06

    A novel oxide material (MIN-I) comprising YO.sub.2; and X.sub.2O.sub.3, wherein Y is a tetravalent element and X is a trivalent element, wherein X/Y=O or Y/X=30 to 100 is provided. Surprisingly, MIN-I can be reversibly deswollen. MIN-I can further be combined with a polymer to produce a nanocomposite, depolymerized to produce predominantly fully exfoliated layers (MIN-2), and pillared to produce a pillared oxide material (MIN-3), analogous to MCM-36. The materials are useful in a wide range of applications, such as catalysts, thin films, membranes, and coatings.

  13. Nano transfer and nanoreplication using deterministically grown sacrificial nanotemplates

    Science.gov (United States)

    Melechko, Anatoli V. (Oak Ridge, TN); McKnight, Timothy E. (Greenback, TN); Guillorn, Michael A. (Ithaca, NY); Ilic, Bojan (Ithaca, NY); Merkulov, Vladimir I. (Knoxville, TX); Doktycz, Mitchel J. (Knoxville, TN); Lowndes, Douglas H. (Knoxville, TN); Simpson, Michael L. (Knoxville, TN)

    2012-03-27

    Methods, manufactures, machines and compositions are described for nanotransfer and nanoreplication using deterministically grown sacrificial nanotemplates. An apparatus, includes a substrate and a nanoconduit material coupled to a surface of the substrate. The substrate defines an aperture and the nanoconduit material defines a nanoconduit that is i) contiguous with the aperture and ii) aligned substantially non-parallel to a plane defined by the surface of the substrate.

  14. Atomic Layer Thermopile Materials: Physics and Application

    Directory of Open Access Journals (Sweden)

    H.-U. Habermeier

    2008-11-01

    Full Text Available New types of thermoelectric materials characterized by highly anisotropic Fermi surfaces and thus anisotropic Seebeck coefficients are reviewed. Early studies revealed that there is an induced voltage in high TC oxide superconductors when the surface of the films is exposed to short light pulses. Subsequent investigations proved that the effect is due to anisotropic components of the Seebeck tensor, and the type of materials is referred to atomic layer thermopile (ALT. Our recent studies indicate that multilayer thin films at the nanoscale demonstrate enhanced ALT properties. This is in agreement with the prediction in seeking the larger figure of merit (ZT thermoelectric materials in nanostructures. The study of ALT materials provides both deep insight of anisotropic transport property of these materials and at the same time potential materials for applications, such as light detector and microcooler. By measuring the ALT properties under various perturbations, it is found that the information on anisotropic transport properties can be provided. The information sometimes is not easily obtained by other tools due to the nanoscale phase coexistence in these materials. Also, some remained open questions and future development in this research direction have been well discussed.

  15. Toughening elastomers with sacrificial bonds and watching them break.

    Science.gov (United States)

    Ducrot, Etienne; Chen, Yulan; Bulters, Markus; Sijbesma, Rint P; Creton, Costantino

    2014-04-11

    Elastomers are widely used because of their large-strain reversible deformability. Most unfilled elastomers suffer from a poor mechanical strength, which limits their use. Using sacrificial bonds, we show how brittle, unfilled elastomers can be strongly reinforced in stiffness and toughness (up to 4 megapascals and 9 kilojoules per square meter) by introducing a variable proportion of isotropically prestretched chains that can break and dissipate energy before the material fails. Chemoluminescent cross-linking molecules, which emit light as they break, map in real time where and when many of these internal bonds break ahead of a propagating crack. The simple methodology that we use to introduce sacrificial bonds, combined with the mapping of where bonds break, has the potential to stimulate the development of new classes of unfilled tough elastomers and better molecular models of the fracture of soft materials. PMID:24723609

  16. Nanomanufacturing : nano-structured materials made layer-by-layer.

    Energy Technology Data Exchange (ETDEWEB)

    Cox, James V.; Cheng, Shengfeng; Grest, Gary Stephen; Tjiptowidjojo, Kristianto (University of New Mexico); Reedy, Earl David, Jr.; Fan, Hongyou; Schunk, Peter Randall; Chandross, Michael Evan; Roberts, Scott A.

    2011-10-01

    Large-scale, high-throughput production of nano-structured materials (i.e. nanomanufacturing) is a strategic area in manufacturing, with markets projected to exceed $1T by 2015. Nanomanufacturing is still in its infancy; process/product developments are costly and only touch on potential opportunities enabled by growing nanoscience discoveries. The greatest promise for high-volume manufacturing lies in age-old coating and imprinting operations. For materials with tailored nm-scale structure, imprinting/embossing must be achieved at high speeds (roll-to-roll) and/or over large areas (batch operation) with feature sizes less than 100 nm. Dispersion coatings with nanoparticles can also tailor structure through self- or directed-assembly. Layering films structured with these processes have tremendous potential for efficient manufacturing of microelectronics, photovoltaics and other topical nano-structured devices. This project is designed to perform the requisite R and D to bring Sandia's technology base in computational mechanics to bear on this scale-up problem. Project focus is enforced by addressing a promising imprinting process currently being commercialized.

  17. Radionuclide separations using pillared layered materials

    International Nuclear Information System (INIS)

    This is the final report of a two-year Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Pillared Layered Materials (PLMs) are layered inorganic ion exchangers propped apart by metal oxide pillars. PLMs have been synthesized to sorb strontium from liquid nuclear wastes. A study that compared over 60 sorbers for their ability to sorb strontium from Hanford simulants showed that PLMs were the best sorbers; strontium distribution coefficients (SrKd) > 20000 mL/g were obtained. In addition, PLMs showed a high degree of selectivity for strontium over cesium, transition metals, lanthanides and actinides. The sorption of strontium is, however, inhibited by complexants (EDTA); SrKd values drop to d values for Sr2+ and Ba2+ show a strong pH dependence; Kd values increase to >104 above pH 12. The general surface complexation mechanism explains the sorption of these cations on PLMs

  18. Protective nitrided layers for thermonuclear reactor materials

    International Nuclear Information System (INIS)

    Radiation resistance and hydrogen permeability of nitrided layer of steel 08Kh18N10T-perspective material for the first wall of thermonuclear reactor-have been investigated. The nitrided layer was produced in the flow of high-purity nitrogen at 1000 deg C for 80 min, 8h 10 min and 22 h; diffusion zones 50, 150 and 200 ?m wide respectively were obtained. It is established, that irradiation with helium and hydrogen ions at 400-450 deg C by the doses up to 5x1019 cm-1 practically does not change the sample surface. The zone of internal nitridation, containing fine dispersed particles of Cr2N, decreases noticeally the steel hydrogen permeability

  19. Layered Atom Arrangements in Complex Materials

    Energy Technology Data Exchange (ETDEWEB)

    K.E. Sikafus; R.W.Grimes; S.M.Corish; A.R. Cleave; M.Tang; C.R.Stanek; B.P. Uberuaga; J.A.Valdez

    2005-04-15

    In this report, we develop an atom layer stacking model to describe systematically the crystal structures of complex materials. To illustrate the concepts, we consider a sequence of oxide compounds in which the metal cations progress in oxidation state from monovalent (M{sup 1+}) to tetravalent (M{sup 4+}). We use concepts relating to geometric subdivisions of a triangular atom net to describe the layered atom patterns in these compounds (concepts originally proposed by Shuichi Iida). We demonstrate that as a function of increasing oxidation state (from M{sup 1+} to M{sup 4+}), the layer stacking motifs used to generate each successive structure (specifically, motifs along a 3 symmetry axis), progress through the following sequence: MMO, MO, M{sub r}O, MO{sub r/s}O{sub u/v}, MOO (where M and O represent fully dense triangular atom nets and r/s and u/v are fractions used to describe partially filled triangular atom nets). We also develop complete crystallographic descriptions for the compounds in our oxidation sequence using trigonal space group R{bar 3}.

  20. The role of topology and thermal backbone fluctuations on sacrificial bond efficacy in mechanical metalloproteins

    International Nuclear Information System (INIS)

    Sacrificial bonding is a ubiquitous cross-linking strategy for increasing toughness that is found throughout nature in various biological materials such as bone, wood, silk and mussel byssal threads. However, the molecular mechanism of sacrificial bonding remains only poorly understood. Molecular modeling possesses a strong potential to provide insights into the behavior of these cross-links. Here we use Monte Carlo simulations to investigate the effect of reversible sacrificial binding sites on the mechanical properties of single linear polymer chains based on load-bearing metalloproteins found in the mussel byssus. It is shown that the topology of the bonds determines the position and spacing of sacrificial force peaks, while the height of these peaks is intimately tied to the magnitude of thermal fluctuations in the chain that are dependent on effective chain length. These results bear important implications for understanding natural systems and for the generation of strong and ductile biomimetic polymers. (paper)

  1. Electrically actuated sacrificial membranes for valving in microsystems

    Science.gov (United States)

    Allain, M.; Berthier, J.; Basrour, S.; Pouteau, P.

    2010-03-01

    Valving is essential to microflow circuits and networks in microsystem technology. Many different types of valves have been designed and fabricated. Membranes of sacrificial material have already been designed for one-shot valving. However, the new design proposed here, based on sacrificial micro-membranes with embedded electrodes, has the advantages of being efficient, easily controllable and requiring very low energy levels. We have shown that a 100 µm × 100 µm × 500 nm Si3N4 membrane with a platinum electrode can be actuated to break up with an energy input of only 6 µJ, during an actuation time of 200 µs. At rest, in the absence of actuation, such membranes can withstand a pressure of 1 bar. The goal of the development of such membranes is to hydrodynamically connect, one by one, a series of initially isolated micro-chambers implemented in a silicon chip.

  2. Atomic layer deposition of metal sulfide materials.

    Science.gov (United States)

    Dasgupta, Neil P; Meng, Xiangbo; Elam, Jeffrey W; Martinson, Alex B F

    2015-02-17

    CONSPECTUS: The field of nanoscience is delivering increasingly intricate yet elegant geometric structures incorporating an ever-expanding palette of materials. Atomic layer deposition (ALD) is a powerful driver of this field, providing exceptionally conformal coatings spanning the periodic table and atomic-scale precision independent of substrate geometry. This versatility is intrinsic to ALD and results from sequential and self-limiting surface reactions. This characteristic facilitates digital synthesis, in which the film grows linearly with the number of reaction cycles. While the majority of ALD processes identified to date produce metal oxides, novel applications in areas such as energy storage, catalysis, and nanophotonics are motivating interest in sulfide materials. Recent progress in ALD of sulfides has expanded the diversity of accessible materials as well as a more complete understanding of the unique chalcogenide surface chemistry. ALD of sulfide materials typically uses metalorganic precursors and hydrogen sulfide (H2S). As in oxide ALD, the precursor chemistry is critical to controlling both the film growth and properties including roughness, crystallinity, and impurity levels. By modification of the precursor sequence, multicomponent sulfides have been deposited, although challenges remain because of the higher propensity for cation exchange reactions, greater diffusion rates, and unintentional annealing of this more labile class of materials. A deeper understanding of these surface chemical reactions has been achieved through a combination of in situ studies and quantum-chemical calculations. As this understanding matures, so does our ability to deterministically tailor film properties to new applications and more sophisticated devices. This Account highlights the attributes of ALD chemistry that are unique to metal sulfides and surveys recent applications of these materials in photovoltaics, energy storage, and photonics. Within each application space, the benefits and challenges of novel ALD processes are emphasized and common trends are summarized. We conclude with a perspective on potential future directions for metal chalcogenide ALD as well as untapped opportunities. Finally, we consider challenges that must be addressed prior to implementing ALD metal sulfides into future device architectures. PMID:25581295

  3. Atomic layer deposition of nanostructured materials

    CERN Document Server

    Pinna, Nicola

    2012-01-01

    Atomic layer deposition, formerly called atomic layer epitaxy, was developed in the 1970s to meet the needs of producing high-quality, large-area fl at displays with perfect structure and process controllability. Nowadays, creating nanomaterials and producing nanostructures with structural perfection is an important goal for many applications in nanotechnology. As ALD is one of the important techniques which offers good control over the surface structures created, it is more and more in the focus of scientists. The book is structured in such a way to fi t both the need of the expert reader (du

  4. Quantifying the Stacking Registry Matching in Layered Materials

    CERN Document Server

    Hod, Oded

    2010-01-01

    A detailed account of a recently developed method [Marom et al., Phys. Rev. Lett. 105, 046801 (2010)] to quantify the registry mismatch in layered materials is presented. The registry index, which was originally defined for planar hexagonal boron-nitride, is extended to treat graphitic systems and generalized to describe multi-layered nanotubes. It is shown that using simple geometric considerations it is possible to capture the complex physical features of interlayer sliding in layered materials. The intuitive nature of the presented model and the efficiency of the related computations suggest that the method can be used as a powerful characterization tool for interlayer interactions in complex layered systems.

  5. Examples of material solutions in bimetallic layered castings

    OpenAIRE

    S. Tenerowicz; M. Cholewa; T. Wróbela

    2011-01-01

    In paper is presented technology of bimetallic layered castings based on founding method of layer coating directly in cast process so-called method of mould cavity preparation. Prepared castings consist two fundamental parts i.e. bearing part and working part (layer). The bearing part of bimetallic layered casting is typical foundry material i.e. pearlitic grey cast iron, whereas working part (layer) is depending on accepted variant plates of alloy steels sort X6Cr13, X12Cr13, X10CrNi18-8 and...

  6. Redox buffered hydrofluoric acid etchant for the reduction of galvanic attack during release etching of MEMS devices having noble material films

    Science.gov (United States)

    Hankins, Matthew G. (Albuquerque, NM)

    2009-10-06

    Etchant solutions comprising a redox buffer can be used during the release etch step to reduce damage to the structural layers of a MEMS device that has noble material films. A preferred redox buffer comprises a soluble thiophosphoric acid, ester, or salt that maintains the electrochemical potential of the etchant solution at a level that prevents oxidation of the structural material. Therefore, the redox buffer preferentially oxidizes in place of the structural material. The sacrificial redox buffer thereby protects the exposed structural layers while permitting the dissolution of sacrificial oxide layers during the release etch.

  7. Nanoprocessing of layered crystalline materials by atomic force microscopy

    Science.gov (United States)

    Miyake, Shojiro; Wang, Mei

    2015-03-01

    By taking advantage of the mechanical anisotropy of crystalline materials, processing at a single-layer level can be realized for layered crystalline materials with periodically weak bonds. Mica (muscovite), graphite, molybdenum disulfide (MoS2), and boron nitride have layered structures, and there is little interaction between the cleavage planes existing in the basal planes of these materials. Moreover, it is easy to image the atoms on the basal plane, where the processed shape can be observed on the atomic level. This study reviews research evaluating the nanometer-scale wear and friction as well as the nanometer-scale mechanical processing of muscovite using atomic force microscopy (AFM). It also summarizes recent AFM results obtained by our research group regarding the atomic-scale mechanical processing of layered materials including mica, graphite, MoS2, and highly oriented pyrolytic graphite.

  8. Method for depositing layers of high quality semiconductor material

    Science.gov (United States)

    Guha, Subhendu (Troy, MI); Yang, Chi C. (Troy, MI)

    2001-08-14

    Plasma deposition of substantially amorphous semiconductor materials is carried out under a set of deposition parameters which are selected so that the process operates near the amorphous/microcrystalline threshold. This threshold varies as a function of the thickness of the depositing semiconductor layer; and, deposition parameters, such as diluent gas concentrations, must be adjusted as a function of layer thickness. Also, this threshold varies as a function of the composition of the depositing layer, and in those instances where the layer composition is profiled throughout its thickness, deposition parameters must be adjusted accordingly so as to maintain the amorphous/microcrystalline threshold.

  9. Ablative Laser Propulsion Using Multi-Layered Material Systems

    Science.gov (United States)

    Nehls, Mary; Edwards, David; Gray, Perry; Schneider, T.

    2002-01-01

    Experimental investigations are ongoing to study the force imparted to materials when subjected to laser ablation. When a laser pulse of sufficient energy density impacts a material, a small amount of the material is ablated. A torsion balance is used to measure the momentum produced by the ablation process. The balance consists of a thin metal wire with a rotating pendulum suspended in the middle. The wire is fixed at both ends. Recently, multi-layered material systems were investigated. These multi-layered materials were composed of a transparent front surface and opaque sub surface. The laser pulse penetrates the transparent outer surface with minimum photon loss and vaporizes the underlying opaque layer.

  10. Examples of material solutions in bimetallic layered castings

    Directory of Open Access Journals (Sweden)

    S. Tenerowicz

    2011-07-01

    Full Text Available In paper is presented technology of bimetallic layered castings based on founding method of layer coating directly in cast process so-called method of mould cavity preparation. Prepared castings consist two fundamental parts i.e. bearing part and working part (layer. The bearing part of bimetallic layered casting is typical foundry material i.e. pearlitic grey cast iron, whereas working part (layer is depending on accepted variant plates of alloy steels sort X6Cr13, X12Cr13, X10CrNi18-8 and X2CrNiMoN22-5-3. The ratio of thickness between bearing and working part is 8:1. The verification of the bimetallic layered castings was evaluated on the basis of ultrasonic NDT (non-destructive testing, structure and macro- and microhardness researches.

  11. Crystallographic dependence of the lateral undercut wet etch rate of Al0.5In0.5P in diluted HCl for III-V sacrificial release

    DEFF Research Database (Denmark)

    Ansbk, Thor; Semenova, Elizaveta; Yvind, Kresten; Hansen, Ole

    2013-01-01

    The authors investigated the use of InAlP as a sacrificial layer lattice-matched to GaAs when diluted hydrochloric acid is used for sacrificial etching. They show that InAlP can be used to fabricate submicrometer air gaps in micro-opto-electro-mechanical systems and that a selectivity toward Ga...

  12. Epitaxially Grown Layered MFI–Bulk MFI Hybrid Zeolitic Materials

    KAUST Repository

    Kim, Wun-gwi

    2012-11-27

    The synthesis of hybrid zeolitic materials with complex micropore-mesopore structures and morphologies is an expanding area of recent interest for a number of applications. Here we report a new type of hybrid zeolite material, composed of a layered zeolite material grown epitaxially on the surface of a bulk zeolite material. Specifically, layered (2-D) MFI sheets were grown on the surface of bulk MFI crystals of different sizes (300 nm and 10 μm), thereby resulting in a hybrid material containing a unique morphology of interconnected micropores (∼0.55 nm) and mesopores (∼3 nm). The structure and morphology of this material, referred to as a "bulk MFI-layered MFI" (BMLM) material, was elucidated by a combination of XRD, TEM, HRTEM, SEM, TGA, and N2 physisorption techniques. It is conclusively shown that epitaxial growth of the 2-D layered MFI sheets occurs in at least two principal crystallographic directions of the bulk MFI crystal and possibly in the third direction as well. The BMLM material combines the properties of bulk MFI (micropore network and mechanical support) and 2-D layered MFI (large surface roughness, external surface area, and mesoporosity). As an example of the uses of the BMLM material, it was incorporated into a polyimide and fabricated into a composite membrane with enhanced permeability for CO2 and good CO2/CH4 selectivity for gas separations. SEM-EDX imaging and composition analysis showed that the polyimide and the BMLM interpenetrate into each other, thereby forming a well-adhered polymer/particle microstructure, in contrast with the defective interfacial microstructure obtained using bare MFI particles. Analysis of the gas permeation data with the modified Maxwell model also allows the estimation of the effective volume of the BMLM particles, as well as the CO2 and CH4 gas permeabilities of the interpenetrated layer at the BMLM/polyimide interface. © 2012 American Chemical Society.

  13. Love wave propagation in functionally graded piezoelectric material layer.

    Science.gov (United States)

    Du, Jianke; Jin, Xiaoying; Wang, Ji; Xian, Kai

    2007-03-01

    An exact approach is used to investigate Love waves in functionally graded piezoelectric material (FGPM) layer bonded to a semi-infinite homogeneous solid. The piezoelectric material is polarized in z-axis direction and the material properties change gradually with the thickness of the layer. We here assume that all material properties of the piezoelectric layer have the same exponential function distribution along the x-axis direction. The analytical solutions of dispersion relations are obtained for electrically open or short circuit conditions. The effects of the gradient variation of material constants on the phase velocity, the group velocity, and the coupled electromechanical factor are discussed in detail. The displacement, electric potential, and stress distributions along thickness of the graded layer are calculated and plotted. Numerical examples indicate that appropriate gradient distributing of the material properties make Love waves to propagate along the surface of the piezoelectric layer, or a bigger electromechanical coupling factor can be obtained, which is in favor of acquiring a better performance in surface acoustic wave (SAW) devices. PMID:17107699

  14. A Cosserat multiparticle model for periodically layered materials

    OpenAIRE

    Lebee, Arthur; Sab, Karam

    2010-01-01

    In this paper, the Cosserat multiparticle model (CM2) for 3D periodically layered materials is proposed in order to reproduce both size and boundary effects in these materials. This model can handle n- phase periodically layered materials with 4n+1 kinematic variables at each 3D geometric point: two in-plane displacements and two rotations per phase plus one common out-of-plane displacement. The model gives excellent agreement with full finite element results for out-of-plane shearing.

  15. Electromagnetic cloaking by layered structure of homogeneous isotropic materials

    CERN Document Server

    Huang, Ying; Jian, Tian

    2007-01-01

    Electromagnetic invisibility cloak requires material with anisotropic distribution of the constitutive parameters deduced from a geometrical transformation as first proposed by Pendry et al. [Science 312, 1780 (2006)]. In this paper, we proposed a useful method to realize the required radius-dependent, anisotropic material parameters and to construct an electromagnetic cloak through concentric layered structure of thin, alternating layers of homogeneous isotropic materials. With proper design of the permittivity or the thickness ratio of the alternating layers, we demonstrated the low-reflection and power-flow bending properties of the proposed cloaking structure through rigorous analysis of the scattered electromagnetic fields. The proposed cloaking structure does not require anisotropy or inhomogeneity of the material constitutive parameters usually realized by metamaterials with subwavelength structured inclusions, therefore may lead to a practical path to an experimental demonstration of electromagnetic c...

  16. Dark material in the polar layered deposits on Mars

    Science.gov (United States)

    Herkenhoff, Ken

    1992-12-01

    The Martian polar layered deposits probably record periodic variations in the deposition of dust and ice caused by climate changes over the past 10 to 100 million years. The polar layered deposits appear to be the source of dark, saltating material that has been distributed over the surface of Mars, but the mechanisms by which this material is incorporated and eroded from the layered deposits is unknown. These mechanisms must be understood before the processes that formed and modified the layered deposits can be inferred and related to Martian climate changes. In summary, weathering of the Martian layered deposits by sublimation of water ice may account for the geologic relationships observed in the Martian polar regions. The non-volatile components of the layered deposits appears to consist mainly of bright red dust, with small amounts of dark dust or sand. Alternatively, dark sand-sized basaltic particles may occasionally be transported onto the layered deposits, forming thin layers. Once eroded, particles of either type may saltate to form the dark dunes found in both polar regions.

  17. Plasma assisted synthesis of hollow nanofibers using electrospun sacrificial templates

    Energy Technology Data Exchange (ETDEWEB)

    Rahmathullah, Aflal M.; Jason Robinette, E.; Chen Hong; Elabd, Yossef A. [Department of Chemical and Biological Engineering, Drexel University, PA 19104 (United States); Palmese, Giuseppe R. [Department of Chemical and Biological Engineering, Drexel University, PA 19104 (United States)], E-mail: palmese@coe.drexel.edu

    2007-12-15

    In this work, we describe the synthesis of nanostructured polymeric materials of controlled tubular geometries using oxygen plasma and polysiloxane-grafting onto electrospun fiber sacrificial templates. The fibers were characterized using Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) to determine the extent of grafting, graft chemistry and the influence of plasma treatment. Scanning electron microscopy (SEM) was used to determine the morphology and size of the electrospun fibers and nanotubes. The average diameter of the electrospun fibers employed ranged between 300 nm and 1500 nm. The micrographs revealed differences that are dependent on the type of grafting chemistry as well as plasma treatment times. The template synthesis of polysiloxane nanotubes using polyester track-etched membranes also shows that the technique is applicable to different substrates.

  18. Incorporating microorganisms into polymer layers provides bioinspired functional living materials

    OpenAIRE

    Gerber, Lukas C.; Koehler, Fabian M.; Grass, Robert N; Stark, Wendelin J.

    2011-01-01

    Artificial two-dimensional biological habitats were prepared from porous polymer layers and inoculated with the fungus Penicillium roqueforti to provide a living material. Such composites of classical industrial ingredients and living microorganisms can provide a novel form of functional or smart materials with capability for evolutionary adaptation. This allows realization of most complex responses to environmental stimuli. As a conceptual design, we prepared a material surface with self-cle...

  19. Sacrificial component fabrication for optimised production of micro-vascular polymer composite

    Science.gov (United States)

    Dalton, B.; Dixon, D.; McIlhagger, A.; Archer, E.

    2015-02-01

    Smart functional materials are a viable future goal for advanced applications in aerospace, space and medical applications. In this work micro-vascular polymer composite systems have been developed using sacrificial fibres produced from catalyst loaded Poly(lactic acid). The sacrificial fibres have been produced via a published technique which treated PLA in a solvent catalyst mixture of 60% Trifluoroethanol, 40% H2O dispersed with 10 wt% tin (II) oxalate catalyst. A second process of polymer extrusion of PLA using graded fill contents of tin (II) oxalate has also been developed for the up scaled production of fibres as an alternative to solution treatment. Thermal analysis (TGA) was used to compare sacrificial fibre specimens. PLA fibres produced via the polymer extrusion method outperformed solution treated fibres displaying a lower degradation onset temperature (average 25C lower), higher degradation rates (observed through a derivative curve comparison) and lower residual catalyst content (0.67% solvent treated fibre against 0.16% extruded fibre). The continuous extrusion process is solvent free and is suitable for high volume production. This work has been carried out to fully understand the fabrication issues with sacrificial components.

  20. Contact mechanics of layered elastic materials: experiment and theory

    International Nuclear Information System (INIS)

    This paper reports an experimental and theoretical investigation of the indentation of a layered elastic solid, with special reference to the surface force apparatus (SFA). The contacting surfaces of the SFA comprise a 3-layer material: a thin mica surface layer on a thicker epoxy layer supported by a thick silica substrate. An existing finite element analysis of the deformation of ideal mica/epoxy/silica surfaces used in the SFA is adapted to compare with the experimental measurements of the variation of contact size with load, both with and without adhesion at the interface. This is in marked difference to the Johnson, Kendall and Roberts (JKR) theory for homogeneous solids. Experiments and finite element calculations were also carried out on the elastic indentation of a thin (5.5 ?m) layer of mica on a very thick layer of epoxy (>100 ?m). As input data for the calculations, the elastic moduli of the mica and epoxy were measured in separate indentation experiments. The stiffness of a layered solid can be expressed by an 'effective modulus' Ee*, which has been deduced from the experimental measurements and compared with the theoretical values with fair success. The work of adhesion is commonly measured in the SFA by observing the 'pull-off force' to separate the surfaces. The theory shows that, for a layered solid, the pull-force can vary significantly from the JKR value for a homogeneous solid. In particular, it was found that the mica surface energy, ?sv, measured by SFA experiments using crossed cylinders of mean radius R, where the materials are layered and the mica/mica adhesion is high, can vary with the pull-off force Fp according to Fp/4?R sv p/2?R, and for this particular experiment was given as ?sv = Fp/3.5 ?R as compared with ?sv = Fp/3?R for homogeneous materials

  1. Layered material characterization using ultrasonic transmission. An inverse estimation methodology.

    Science.gov (United States)

    Messineo, María G; Rus, Guillermo; Eliçabe, Guillermo E; Frontini, Gloria L

    2016-02-01

    This paper presents an inverse methodology with the aim to characterize a layered material through the identification of acoustical and mechanical properties of its layers. The framework to accomplish this objective is provided by the Inverse Problems (IPs) theory. Material characterization refers to the detection and localization of discontinuities, as well as to the identification of physical properties, in order to predict the material behaviour. In this particular case, the IP is solved in the form of a parameter estimation problem, in which the goal is the estimation of the characteristic acoustic impedance, transit time, and attenuation of each layer. These parameters are directly related to relevant material properties, such as the speed of sound, density, elastic modulus and elastic energy dissipation constants. The IP solution is obtained by minimizing a cost functional formulated as the least squares error between the waveform calculated using an equivalent model, and the measured waveform obtained from ultrasonic transmission tests. The applied methodology allowed the accurate estimation of the desired parameters in materials composed of up to three layers. As a second contribution, a power law frequency dependence of the wave attenuation was identified for several homogeneous materials, based on the same ultrasonic transmission experiments. PMID:26456278

  2. Designing high-performance layered thermoelectric materials through orbital engineering.

    Science.gov (United States)

    Zhang, Jiawei; Song, Lirong; Madsen, Georg K H; Fischer, Karl F F; Zhang, Wenqing; Shi, Xun; Iversen, Bo B

    2016-01-01

    Thermoelectric technology, which possesses potential application in recycling industrial waste heat as energy, calls for novel high-performance materials. The systematic exploration of novel thermoelectric materials with excellent electronic transport properties is severely hindered by limited insight into the underlying bonding orbitals of atomic structures. Here we propose a simple yet successful strategy to discover and design high-performance layered thermoelectric materials through minimizing the crystal field splitting energy of orbitals to realize high orbital degeneracy. The approach naturally leads to design maps for optimizing the thermoelectric power factor through forming solid solutions and biaxial strain. Using this approach, we predict a series of potential thermoelectric candidates from layered CaAl2Si2-type Zintl compounds. Several of them contain nontoxic, low-cost and earth-abundant elements. Moreover, the approach can be extended to several other non-cubic materials, thereby substantially accelerating the screening and design of new thermoelectric materials. PMID:26948043

  3. Visibility of two-dimensional layered materials on various substrates

    Science.gov (United States)

    Mller, M. R.; Gumprich, A.; Ecik, E.; Kallis, K. T.; Winkler, F.; Kardynal, B.; Petrov, I.; Kunze, U.; Knoch, J.

    2015-10-01

    For the investigation of 2D layered materials such as graphene, transition-metal dichalcogenides, boron nitride, and their heterostructures, dedicated substrates are required to enable unambiguous identification through optical microscopy. A systematic study is conducted, focusing on various 2D layered materials and substrates. The simulated colors are displayed and compared with microscopy images. Additionally, the issue of defining an appropriate index for measuring the degree of visibility is discussed. For a wide range of substrate stacks, layer thicknesses for optimum visibility are given along with the resulting sRGB colors. Further simulations of customized stacks can be conducted using our simulation tool, which is available for download and contains a database featuring a wide range of materials.

  4. Enhanced Raman Scattering on In-Plane Anisotropic Layered Materials.

    Science.gov (United States)

    Lin, Jingjing; Liang, Liangbo; Ling, Xi; Zhang, Shuqing; Mao, Nannan; Zhang, Na; Sumpter, Bobby G; Meunier, Vincent; Tong, Lianming; Zhang, Jin

    2015-12-16

    Surface-enhanced Raman scattering (SERS) on two-dimensional (2D) layered materials has provided a unique platform to study the chemical mechanism (CM) of the enhancement due to its natural separation from electromagnetic enhancement. The CM stems from the charge interactions between the substrate and molecules. Despite the extensive studies of the energy alignment between 2D materials and molecules, an understanding of how the electronic properties of the substrate are explicitly involved in the charge interaction is still unclear. Lately, a new group of 2D layered materials with anisotropic structures, including orthorhombic black phosphorus (BP) and triclinic rhenium disulfide (ReS2), has attracted great interest due to their unique anisotropic electrical and optical properties. Herein, we report a unique anisotropic Raman enhancement on few-layered BP and ReS2 using copper phthalocyanine (CuPc) molecules as a Raman probe, which is absent on isotropic graphene and h-BN. According to detailed Raman tensor analysis and density functional theory calculations, anisotropic charge interactions between the 2D materials and molecules are responsible for the angular dependence of the Raman enhancement. Our findings not only provide new insights into the CM process in SERS, but also open up new avenues for the exploration and application of the electronic properties of anisotropic 2D layered materials. PMID:26583533

  5. Interlayer commensurability and superlubricity in rigid layered materials

    Science.gov (United States)

    Hod, Oded

    2012-08-01

    Superlubricity is a frictionless tribological state sometimes occurring in nanoscale material junctions. It is often associated with incommensurate surface lattice structures appearing at the interface. Here, by using the recently introduced registry-index concept that quantifies the registry mismatch in layered materials and reproduces their interlayer sliding energy landscape, we prove the existence of a direct relation between interlayer commensurability and wearless friction in rigid layered materials. We show that our simple and intuitive model is able to capture, down to fine details, the experimentally measured frictional behavior of a hexagonal graphene flake sliding on top of the surface of graphite. We further predict that superlubricity is expected to occur in hexagonal boron nitride as well with tribological characteristics very similar to those observed for the graphitic system. The success of our method in predicting experimental results along with its high computational efficiency marks the registry index as a promising tool for studying tribological properties of nanoscale material interfaces.

  6. Structure, Orientation and Stability of Lysozyme Confined in layered Materials

    OpenAIRE

    Balme, Sbastien; Gugan, Rgis; Janot, Jean-Marc; Jaber, Maguy; Lepoitevin, Mathilde; Dejardin, Philippe; Bourrat, Xavier; Motelica-Heino, Mikael

    2013-01-01

    The confinement of lysozyme in 3 layered materials based on montmorillonite and lamellar double hydroxide exhibiting different surface charges was studied. The protein structure and orientation in these materials were determined by X-Ray diffraction, time resolved fluorescence and fluorescence anisotropy. For both Montmorillonite exchanged with sodium and modified with non-ionic surfactant (tri-ethylene glycol mono n-decyl ether), the lysozyme was found to be located in the interlayer space w...

  7. The effect of gamma irradiation on few layered graphene materials

    OpenAIRE

    Ansn Casaos, Alejandro; Purtolas, J. A.; Pascual, F.J.; Hernndez-Ferrer, J.; Castell, Pere; Benito,Ana M.; Maser, Wolfgang K.; Martnez, M. Teresa

    2014-01-01

    The effect of -irradiation on the structure and composition of chemically synthesized few-layered graphene materials was studied. Fully oxidized graphene oxide and graphene nanoribbons, as well as their respective chemically post-reduced forms, were treated under -irradiation in an air-sealed environment. Three different irradiation doses of 60, 90 and 150 kGy were applied. Structure and composition of the irradiated materials were analyzed by X-ray diffraction (XRD), Fourier...

  8. Mechanics of freely-suspended ultrathin layered materials

    Energy Technology Data Exchange (ETDEWEB)

    Castellanos-Gomez, Andres [Kavli Institute of Nanoscience, Delft University of Technology (Netherlands); Instituto Madrileno de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Madrid (Spain); Singh, Vibhor; Zant, Herre S.J. van der; Steele, Gary A. [Kavli Institute of Nanoscience, Delft University of Technology (Netherlands)

    2015-01-01

    The study of atomically thin two-dimensional materials is a young and rapidly growing field. In the past years, a great advance in the study of the remarkable electrical and optical properties of 2D materials fabricated by exfoliation of bulk layered materials has been achieved. Due to the extraordinary mechanical properties of these atomically thin materials, they also hold a great promise for future applications such as flexible electronics. For example, this family of materials can sustain very large deformations without breaking. Due to the combination of small dimensions, high Young's modulus and high crystallinity of 2D materials, they have attracted the attention of the field of nanomechanical systems as high frequency and high quality factor resonators. In this article, we review experiments on static and dynamic response of 2D materials. We provide an overview and comparison of the mechanics of different materials, and highlight the unique properties of these thin crystalline layers. We conclude with an outlook of the mechanics of 2D materials and future research directions such as the coupling of the mechanical deformation to their electronic structure. (copyright 2014 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Hydrogen retention in ITER relevant mixed material layers

    International Nuclear Information System (INIS)

    D retention in mixed layers of ITER first wall materials, i.e. Be2C (prepared by annealing C film on Be substrate sample at 773 K), Be12W (by annealing W film on Be substrate at 1073 K) and tungsten carbide (by annealing W film on graphite substrate annealed at 1373 K) was investigated under controlled laboratory conditions. D retention in Be2C and Be12W layers was similar to that of Be rather than that of graphite or W respectively, while D retention in tungsten carbide layers was similar to that of polycrystalline W rather than that of graphite. The fluence dependence of the retained D fraction in each mixed layer showed no clear saturation in the experimentally accessible implantation fluence range (23 D/m2), and increased with incident fluence as ??0.2 in Be2C, Be12W and ??0.5 in tungsten carbide.

  10. Thin layer laser bonding using spin-on-glass materials

    International Nuclear Information System (INIS)

    We developed and characterized a new laser bonding process with a nano adhesive layer for transparent materials. The adhesive is spin-coated on a glass substrate and cured locally with a focused laser beam. The minimum viscosity of the adhesive is very low, so that a thin layer only a few hundred nanometers thick can be coated on a cover substrate. Laser irradiation from a Nd:YAG laser system with a wavelength of 1064 nm is employed as the curing source for the localized nano layer bonding process. The measured thickness of the bonding layer is in the range of 400 nm to 3 ?m. This process can be applied to the nano or micro bonding of various transparent systems such as flat panel displays, biochips, and heat-sensitive microelectronics. We present experimental results and discuss the process characteristics

  11. Epitaxial Growth of GaN-based LEDs on Simple Sacrificial Substrates

    Energy Technology Data Exchange (ETDEWEB)

    Ian Ferguson; Chris Summers

    2009-12-31

    The objective of this project is to produce alternative substrate technologies for GaN-based LEDs by developing an ALD interlayer of Al{sub 2}O{sub 3} on sacrificial substrates such as ZnO and Si. A sacrificial substrate is used for device growth that can easily be removed using a wet chemical etchant leaving only the thin GaN epi-layer. After substrate removal, the GaN LED chip can then be mounted in several different ways to a metal heat sink/reflector and light extraction techniques can then be applied to the chip and compared for performance. Success in this work will lead to high efficiency LED devices with a simple low cost fabrication method and high product yield as stated by DOE goals for its solid state lighting portfolio.

  12. Antitumoral materials with regenerative function obtained using a layer-by-layer technique

    Directory of Open Access Journals (Sweden)

    Ficai D

    2015-03-01

    Full Text Available Denisa Ficai,1 Maria Sonmez,1,2 Madalina Georgiana Albu,2 Dan Eduard Mihaiescu,1 Anton Ficai,1 Coralia Bleotu3 1Faculty of Applied Chemistry and Material Science, Politehnica University of Bucharest, 2Leather and Footwear Research Institute, National Research and Development Institute for Textiles and Leather, 3Stefan S Nicolau Institute of Virology, Romanian Academy, Bucharest, Romania Abstract: A layer-by layer technique was successfully used to obtain collagen/hydroxyapatite-magnetite-cisplatin (COLL/HAn-Fe3O4-CisPt, n=17 composite materials with a variable content of hydroxyapatite intended for use in the treatment of bone cancer. The main advantages of this system are the possibility of controlling the rate of delivery of cytostatic agents, the presence of collagen and hydroxyapatite to ensure more rapid healing of the injured bone tissue, and the potential for magnetite to be a passive antitumoral component that can be activated when an appropriate external electromagnetic field is applied. In vitro cytotoxicity assays performed on the COLL/HAn-Fe3O4-CisPt materials obtained using a layer-by layer method confirmed their antitumoral activity. Samples with a higher content of hydroxyapatite had more antitumoral activity because of their better absorption of cisplatin and consequently a higher amount of cisplatin being present in the matrices. Keywords: multifunctional materials, antitumoral activity, scaffold, bone grafts

  13. A 3D interconnected microchannel network formed in gelatin by sacrificial shellac microfibers

    OpenAIRE

    Leon M. Bellan; Pearsall, Matthew; Cropek, Donald; Langer, Robert

    2012-01-01

    3D microfluidic networks are fabricated in a gelatin hydrogel using sacrificial melt-spun microfibers made from a material with pH-dependent solubility. The fibers, after being embedded within the gel, can be removed by changing the gel pH to induce dissolution. This process is performed in an entirely aqueous environment, avoiding extreme temperatures, low pressures, and toxic organic solvents.

  14. 10th International School of Materials Science and Technology : Intercalation in Layered Materials "Ettore Majorana"

    CERN Document Server

    1986-01-01

    This volume is prepared from lecture notes for the course "Intercalation in Layered Materials" which was held at the Ettore Majorana Centre for Scientific Culture at Erice, Sicily in July, 1986, as part of the International School of Materials Science and Tech­ nology. The course itself consisted of formal tutorial lectures, workshops, and informal discussions. Lecture notes were prepared for the formal lectures, and short summaries of many of the workshop presentations were prepared. This volume is based on these lecture notes and research summaries. The material is addressed to advanced graduate students and postdoctoral researchers and assumes a background in basic solid state physics. The goals of this volume on Intercalation in Layered Materials include an introduc­ tion to the field for potential new participants, an in-depth and broad exposure for stu­ dents and young investigators already working in the field, a basis for cross-fertilization between workers on various layered host materials...

  15. Antitumoral materials with regenerative function obtained using a layer-by-layer technique

    OpenAIRE

    Ficai, Denisa; Sonmez, Maria; Albu, Madalina Georgiana; Mihaiescu, Dan Eduard; Ficai, Anton; Bleotu, Coralia

    2015-01-01

    A layer-by layer technique was successfully used to obtain collagen/hydroxyapatite-magnetite-cisplatin (COLL/HAn-Fe3O4-CisPt, n=17) composite materials with a variable content of hydroxyapatite intended for use in the treatment of bone cancer. The main advantages of this system are the possibility of controlling the rate of delivery of cytostatic agents, the presence of collagen and hydroxyapatite to ensure more rapid healing of the injured bone tissue, and the potential for magnetite to be ...

  16. Optical modulators with two-dimensional layered materials

    CERN Document Server

    Sun, Zhipei; Wang, Feng

    2016-01-01

    Light modulation is an essential operation in photonics and optoelectronics. With existing and emerging technologies increasingly demanding compact, efficient, fast and broadband optical modulators, high-performance light modulation solutions are becoming indispensable. The recent realization that two-dimensional layered materials could modulate light with superior performance has prompted intense research and significant advances, paving the way for realistic applications. In this review, we cover the state-of-the-art of optical modulators based on two-dimensional layered materials including graphene, transition metal dichalcogenides and black phosphorus. We discuss recent advances employing hybrid structures, such as two-dimensional heterostructures, plasmonic structures, and silicon/fibre integrated structures. We also take a look at future perspectives and discuss the potential of yet relatively unexplored mechanisms such as magneto-optic and acousto-optic modulation.

  17. Ultralight Weight Optical Systems Using Nano-Layered Synthesized Materials

    Science.gov (United States)

    Clark, Natalie; Breckinridge, James

    2014-01-01

    Optical imaging is important for many NASA science missions. Even though complex optical systems have advanced, the optics, based on conventional glass and mirrors, require components that are thick, heavy and expensive. As the need for higher performance expands, glass and mirrors are fast approaching the point where they will be too large, heavy and costly for spacecraft, especially small satellite systems. NASA Langley Research Center is developing a wide range of novel nano-layered synthesized materials that enable the development and fabrication of ultralight weight optical device systems that enable many NASA missions to collect science data imagery using small satellites. In addition to significantly reducing weight, the nano-layered synthesized materials offer advantages in performance, size, and cost.

  18. Atomic layer deposited aluminum oxide barrier coatings for packaging materials

    International Nuclear Information System (INIS)

    Thin aluminum oxide coatings have been deposited at a low temperature of 80 oC on various uncoated papers, polymer-coated papers and boards and plain polymer films using the atomic layer deposition (ALD) technique. The work demonstrates that such ALD-grown Al2O3 coatings efficiently enhance the gas-diffusion barrier performance of the studied porous and non-porous materials towards oxygen, water vapor and aromas.

  19. Optical Phonon Limited High Field Transport in Layered Materials

    OpenAIRE

    Chandrasekar, Hareesh; Ganapathi, Kolla L.; Bhattacharjee, Shubhadeep; Bhat, Navakanta; Nath, Digbijoy N.

    2015-01-01

    An optical phonon limited velocity model has been employed to investigate high-field transport in a selection of layered 2D materials for both, low-power logic switches with scaled supply voltages, and high-power, high-frequency transistors. Drain currents, effective electron velocities and intrinsic cut-off frequencies as a function of carrier density have been predicted thus providing a benchmark for the optical phonon limited high-field performance limits of these materia...

  20. Study of materials for using at waste layer in repositories

    International Nuclear Information System (INIS)

    This research has an objective to characterize Brazilian clays and to implant a data base containing the information obtained form tests and suppliers. Such information will allow to buy and and to select optimum material for its utilization in the stuffing layer. Brazilian suppliers were contacted for obtaining information and samples, the various clays were tested and these tests comprehend the following: identification of the mineral constituents, determination of the compaction curve as function of the humidity, hydraulic conductivity, humidity and organic material contents, cationic exchange capacity, specific surface, and etc

  1. Nanotubes Motion on Layered Materials: A Registry Perspective

    CERN Document Server

    Oz, Inbal; Itkin, Yaron; Buchwalter, Asaf; Akulov, Katherine; Hod, Oded

    2015-01-01

    At dry and clean material junctions of rigid materials the corrugation of the sliding energy landscape is dominated by variations of Pauli repulsions. These occur when electron clouds centered around atoms in adjacent layers overlap as they slide across each other. In such cases there exists a direct relation between interfacial surface (in)commensurability and superlubricity, a frictionless and wearless tribological state. The Registry Index is a purely geometrical parameter that quanti?es the degree of interlayer commensurability, thus providing a simple and intuitive method for the prediction of sliding energy landscapes at rigid material interfaces. In the present study, we extend the applicability of the Registry Index to non-parallel surfaces, using a model system of nanotubes motion on ?at hexagonal materials. Our method successfully reproduces sliding energy landscapes of carbon nanotubes on Graphene calculated using a Lennard-Jones type and the Kolmogorov-Crespi interlayer potentials. Furthermore, it...

  2. Monolithic multilayer microfluidics via sacrificial molding of 3D-printed isomalt.

    Science.gov (United States)

    Gelber, Matthew K; Bhargava, Rohit

    2015-04-01

    Here we demonstrate a method for creating multilayer or 3D microfluidics by casting a curable resin around a water-soluble, freestanding sacrificial mold. We use a purpose-built 3D printer to pattern self-supporting filaments of the sugar alcohol isomalt, which we then back-fill with a transparent epoxy resin. Dissolving the sacrificial mold leaves a network of cylindrical channels as well as input and output ports. We use this technique to fabricate a combinatorial mixer capable of producing 8 combinations of two fluids in ratios ranging from 1?:?100 to 100?:?1. This approach allows rapid iteration on microfluidic chip design and enables the use of geometry and materials not accessible using conventional soft lithography. The ability to precisely pattern round channels in all three dimensions in hard and soft media may prove enabling for many organ-on-chip systems. PMID:25671493

  3. Self assembled multi-layer nanocomposite of graphene and metal oxide materials

    Science.gov (United States)

    Liu, Jun; Aksay, Ilhan A; Choi, Daiwon; Kou, Rong; Nie, Zimin; Wang, Donghai; Yang, Zhenguo

    2015-04-28

    Nanocomposite materials having at least two layers, each layer consisting of one metal oxide bonded to at least one graphene layer were developed. The nanocomposite materials will typically have many alternating layers of metal oxides and graphene layers, bonded in a sandwich type construction and will be incorporated into an electrochemical or energy storage device.

  4. Capacitive micro force sensors manufactured with mineral sacrificial layers

    OpenAIRE

    Fournier, Yannick; Wiedmer, Simon; Maeder, Thomas; Ryser, Peter

    2007-01-01

    In this work a prototype of micro force sensor of range ?N...mN is presented. Instead of the traditional piezoresistive strain sensing through thick-film resistors used for higher forces, a more effective principle is used: measurement of beam displacement rather than strain. A design of a cantilever sensor with capacitive electrodes, optionally coupled with an electrostatic force cancelling to achieve higher sensitivity, is proposed and discussed. The structuration of the device ...

  5. Antitumoral materials with regenerative function obtained using a layer-by-layer technique.

    Science.gov (United States)

    Ficai, Denisa; Sonmez, Maria; Albu, Madalina Georgiana; Mihaiescu, Dan Eduard; Ficai, Anton; Bleotu, Coralia

    2015-01-01

    A layer-by layer technique was successfully used to obtain collagen/hydroxyapatite-magnetite-cisplatin (COLL/HAn-Fe3O4-CisPt, n=1-7) composite materials with a variable content of hydroxyapatite intended for use in the treatment of bone cancer. The main advantages of this system are the possibility of controlling the rate of delivery of cytostatic agents, the presence of collagen and hydroxyapatite to ensure more rapid healing of the injured bone tissue, and the potential for magnetite to be a passive antitumoral component that can be activated when an appropriate external electromagnetic field is applied. In vitro cytotoxicity assays performed on the COLL/HAn-Fe3O4-CisPt materials obtained using a layer-by layer method confirmed their antitumoral activity. Samples with a higher content of hydroxyapatite had more antitumoral activity because of their better absorption of cisplatin and consequently a higher amount of cisplatin being present in the matrices. PMID:25767374

  6. Evaluation of layer-by-layer graphene structures as supercapacitor electrode materials

    Science.gov (United States)

    Zang, Xiaobei; Li, Peixu; Chen, Qiao; Wang, Kunlin; Wei, Jinquan; Wu, Dehai; Zhu, Hongwei

    2014-01-01

    Very less attention has been paid recently to the electrochemical properties of graphene films with intrinsic flat structure prepared by chemical vapor deposition (CVD). In this work, button supercapacitors were fabricated using ionic liquid as electrolytes and layer-by-layer graphene structures as electrodes. The specific capacitances of the supercapacitors increased with the increase of layer number. The areal specific capacitance of ten-layer graphene supercapacitor was 0.29 mF/cm2 at the scan rate of 50 mV/s, which was about three times of that of monolayer graphene supercapacitor (0.1 mF/cm2). The sandwiched multi-layer structures with oxide deposition further improved the device performance. However, the polycrystalline nature of CVD-grown graphene films introduced structural instability during charge-discharge process, resulting in degraded capacitive performance and cycling stability. Our results suggest that graphene films with intrinsic "in-plane" structure might not be ideal candidates for electrode materials.

  7. Sacrificial template method of fabricating a nanotube

    Science.gov (United States)

    Yang, Peidong (Berkeley, CA); He, Rongrui (Berkeley, CA); Goldberger, Joshua (Berkeley, CA); Fan, Rong (El Cerrito, CA); Wu, Yi-Ying (Albany, CA); Li, Deyu (Albany, CA); Majumdar, Arun (Orinda, CA)

    2007-05-01

    Methods of fabricating uniform nanotubes are described in which nanotubes were synthesized as sheaths over nanowire templates, such as using a chemical vapor deposition process. For example, single-crystalline zinc oxide (ZnO) nanowires are utilized as templates over which gallium nitride (GaN) is epitaxially grown. The ZnO templates are then removed, such as by thermal reduction and evaporation. The completed single-crystalline GaN nanotubes preferably have inner diameters ranging from 30 nm to 200 nm, and wall thicknesses between 5 and 50 nm. Transmission electron microscopy studies show that the resultant nanotubes are single-crystalline with a wurtzite structure, and are oriented along the direction. The present invention exemplifies single-crystalline nanotubes of materials with a non-layered crystal structure. Similar "epitaxial-casting" approaches could be used to produce arrays and single-crystalline nanotubes of other solid materials and semiconductors. Furthermore, the fabrication of multi-sheath nanotubes are described as well as nanotubes having multiple longitudinal segments.

  8. Materials science and technology strained-layer superlattices materials science and technology

    CERN Document Server

    Beer, Albert C; Pearsall, Thomas P

    1991-01-01

    The following blurb to be used for the AP Report and ATI only as both volumes will not appear together there.****Strained-layer superlattices have been developed as an important new form of semiconducting material with applications in integrated electro-optics and electronics. Edited by a pioneer in the field, Thomas Pearsall, this volume offers a comprehensive discussion of strained-layer superlattices and focuses on fabrication technology and applications of the material. This volume combines with Volume 32, Strained-Layer Superlattices: Physics, in this series to cover a broad spectrum of topics, including molecular beam epitaxy, quantum wells and superlattices, strain-effects in semiconductors, optical and electrical properties of semiconductors, and semiconductor devices.****The following previously approved blurb is to be used in all other direct mail and advertising as both volumes will be promoted together.****Strained-layer superlattices have been developed as an important new form of semiconducting ...

  9. Ni-P-NiO electrolytic layers as anode materials

    Energy Technology Data Exchange (ETDEWEB)

    Niedbala, J. [Institute of Physics and Chemistry of Metals (IPCM), Katowice (Poland); Budniok, A. [Institute of Physics and Chemistry of Metals (IPCM), Katowice (Poland); Gierlotka, D. [Institute of Physics and Chemistry of Metals (IPCM), Katowice (Poland); Surowka, J. [Institute of Physics and Chemistry of Metals (IPCM), Katowice (Poland); Matyja, P. [Institute of Physics and Chemistry of Metals (IPCM), Katowice (Poland)

    1995-10-01

    Composite electrolytic layers were obtained on an amorphous nickel base with the addition of nickel oxide, in galvanostatic conditions at a temperature of 293 K, from a nickel-plating electrolyte in the coating containing a suspension of nickel oxide. The content of nickel oxide in the coatings depends on the conditions in which they were obtained. Using the potentiodynamic method, for these composite layers the polarisation curves of the oxygen electroevolution process from the 1 M KOH solution were determined. For comparison, curves were also plotted for copper and an amorphous Ni-P electrode. The electrodes were subjected to anode-cathode cycling in the range from the potential of oxygen evolution to the potential of hydrogen evolution. For the modified electrode materials, the characteristics of the oxygen electroevolution process were again determined. From these results the influence of the electrode material, and also the influence and advantage of preliminary modification of the surfaces of the electrodes on the process of oxygen evolution in an alkaline environment, were estimated. It was indicated that a correlation exists between the values of the exchange current of the oxygen electroevolution reaction and the electro-oxidation ability of ethanoloamine on the electrode materials studied. (orig.)

  10. Sacrificial bonds in stacked-cup carbon nanofibers: biomimetic toughening mechanisms for composite systems.

    Science.gov (United States)

    Palmeri, Marc J; Putz, Karl W; Brinson, L Catherine

    2010-07-27

    Many natural composites, such as nacre or bone, achieve exceptional toughening enhancements through the rupture of noncovalent secondary bonds between chain segments in the organic phase. This "sacrificial bond" rupture dissipates enormous amounts of energy and reveals significant hidden lengths due to unraveling of the highly coiled macromolecules, leaving the structural integrity of their covalent backbones intact to large extensions. In this work, we present the first evidence of similar sacrificial bond mechanisms in the inorganic phase of composites using inexpensive stacked-cup carbon nanofibers (CNF), which are composed of helically coiled graphene sheets with graphitic spacing between adjacent layers. These CNFs are dispersed in a series of high-performance epoxy systems containing trifunctional and tetrafunctional resins, which are traditionally difficult to toughen in light of their highly cross-linked networks. Nonetheless, the addition of only 0.68 wt % CNF yields toughness enhancements of 43-112% for the various blends. Analysis of the relevant toughening mechanisms reveals two heretofore unseen mechanisms using sacrificial bonds that complement the observed crack deflection, rupture, and debonding/pullout that are common to many composite systems. First, embedded nanofibers can splay discretely between adjacent graphitic layers in the side walls; second, crack-bridging nanofibers can unravel continuously. Both of these mechanisms entail the dissipation of the pi-pi interactions between layers in the side walls without compromising the structural integrity of the graphene sheets. Moreover, increases in electrical conductivity of approximately 7-10 orders of magnitude were found, highlighting the multifunctionality of CNFs as reinforcements for the design of tough, inexpensive nanocomposites with improved electrical properties. PMID:20568708

  11. Nanoscale engineering materials by supercritical fluid and atomic layer deposition

    Science.gov (United States)

    Peng, Qing

    With the development of material science and technology, modification of substrates, which have random geometry and high aspect ratio three dimensional (3D) complex structures, with desired functional, reactive and stable coatings becomes important and challenging. The ability to fabricate mono- or multi-layers of functional materials with precisely controlled dimensions, finely tuned composition and molecular structures, attracts significant interests in materials science and is the key to construct such devices and structures at nano- and micro-scale with desired properties. In this study, supercritical carbon dioxide (scCO2) has been studied as an alternative route for modifying substrates due to the unique gas-like (low viscosity, high diffusivity and zero surface tension) and liquid-like properties (high density). (1) The reaction kinetics of metal oxides thin film deposition from pyrolysis of metal organics in scCO2 was studied in detail. This method was demonstrated as a powerful technique to coat oxides, including Al2O3, Ga2O3 and others, into 3D high aspect ratio complex structure of carbon nanotubes (CNTs) forest. (2) The low temperature scCO 2 based hydrogenolysis process was developed as a useful way to functionalize aligned CNTs forest with dense Nickel nanoparticles. On the second part of this work, atomic layer deposition (ALD)/molecular layer deposition (MLD), as a vapor phase, stepwise and self-limiting vacuum based deposition process, was demonstrated as a powerful way to form highly conformal and uniform film onto substrates, even into highly complex 3D complex structures. In this study, (4) Metal oxide ALD is applied onto 3D electrospun polymer microfiber mats template to illustrate an effective and robust strategy to fabricate long and uniform metal oxide microtubes with precisely controllable wall thickness. Designer tubes of various sizes and different materials were demonstrated by using this method. (5) By further extending this technique, complex coaxial Al2O3/ZnO/Al2O3 multilayed microtubular structure is fabricated, which provides an unique platform to study the solid state reaction and diffusion process (Kirkendall Effect) between Al2 O3 shells and the confined middle ZnO layers by annealing the samples at 700C. (6) The extension of ALD-MLD process of polyamides, zinc hybrid, aminosilane self assembly monolayers were studied by various techniques to illustrate the surface reaction mechanism.

  12. KAPOOL experiments to simulate molten corium sacrificial-concrete interaction and gate opening in the EPR core catcher concept

    International Nuclear Information System (INIS)

    In future light water reactors special devices (core catchers) might be required to prevent containment failure by basement erosion after reactor pressure vessel meltthrough during a core meltdown accident. In the case of a postulated core melt down accident in the EPR (European pressurized water reactor) the ex-vessel melt shall be retained and cooled in a special compartment inside the containment to exclude significant radioactive release to the environment. After failure of the reactor pressure vessel the core melt is retained in the reactor cavity for ? 1 h to pick up late melt releases. The reactor cavity is protected by a layer of sacrificial concrete and closed by a steel gate at the bottom. After meltthrough of this gate the core melt should be distributed homogeneously in a special spreading room. A series of experiments has been performed to investigate the erosion of the sacrificial concrete as well as the gate ablation using alumina-iron thermite melts as a simulant for the core melt. Two different sorts of sacrificial concrete have been studied so far: boro-silicate glass concrete and a concrete based on Fe2O3/SiO2. Erosion velocities of the sacrificial concrete, the homogeneity of the melt front and steel gate ablation results are presented in this report. (orig.)

  13. Failure modes and materials design for biomechanical layer structures

    Science.gov (United States)

    Deng, Yan

    Ceramic materials are finding increasing usage in the area of biomechanical replacements---dental crowns, hip and bone implants, etc.---where strength, wear resistance, biocompatibility, chemical durability and even aesthetics are critical issues. Aesthetic ceramic crowns have been widely used in dentistry to replace damaged or missing teeth. However, the failure rates of ceramic crowns, especially all-ceramic crowns, can be 1%6% per year, which is not satisfactory to patients. The materials limitations and underlying fracture mechanisms of these prostheses are not well understood. In this thesis, fundamental fracture and damage mechanisms in model dental bilayer and trilayer structures are studied. Principle failure modes are identified from in situ experimentation and confirmed by fracture mechanics analysis. In bilayer structures of ceramic/polycarbonate (representative of ceramic crown/dentin structure), three major damage sources are identified: (i) top-surface cone cracks or (ii) quasiplasticity, dominating in thick ceramic bilayers; (iii) bottom-surface radial cracks, dominating in thin ceramic bilayers. Critical load P for each damage mode are measured in six dental ceramics: Y-TZP zirconia, glass-infiltrated zirconia and alumina (InCeram), glass-ceramic (Empress II), Porcelain (Mark II and Empress) bonded to polymer substrates, as a function of ceramic thickness d in the range of 100 mum to 10 mm. P is found independent of d for mode (i) and (ii), but has a d 2 relations for mode (iii)---bottom surface radial cracking. In trilayer structures of glass/core-ceramic/polycarbonate (representing veneer porcelain/core/dentin structures), three inner fracture origins are identified: radial cracks from the bottom surface in the (i) first and (ii) second layers; and (iii) quasiplasticity in core-ceramic layer. The role of relative veneer/core thickness, d1/d 2 and materials properties is investigated for three core materials with different modulus (114--270GPa) and strength (400--1400MPa): Y-TZP zirconia, InCeram alumina and Empress II glass-ceramic. Explicit relations for the critical loads P to produce these different damage modes in bilayer and trilayer structures are developed in terms of basic material properties (modulus E, strength, hardness H and toughness T) and geometrical variables (thickness d and contact sphere radius r). These experimentally validated relations are used to design of optimal material combinations for improved fracture resistance and to predict mechanical performance of current dental materials.

  14. Utilization of Industrial Waste Material in GSB Layer

    Directory of Open Access Journals (Sweden)

    U Arun Kumar

    2014-08-01

    Full Text Available India has series of steel plant clusters located along its length and breadth of the territory. Several million metric tons of iron and steel are produced in these plants annually. Along with the production of iron and steel, huge quantities of solid wastes like blast furnace slag and steel slag as well as other wastes such as flue dust, blast furnace sludge, and refractories are also being produced in these plants. These solid wastes can be used as non-traditional/non-conventional aggregates in pavement construction due to acute scarcity of traditional/conventional road construction materials. A study was conducted to investigate the possibility of using Granulated Blast Furnace Slag (GBFS with various blended mixes of traditional/conventional aggregates in subbase layer with different percentages. This study also presents the result of experimental investigation on the influence of Rice husk ash (RHA on the index properties of Red soil which is used as filler material in subbase layer.

  15. Cellulose Nanofibril Hydrogel Tubes as Sacrificial Templates for Freestanding Tubular Cell Constructs.

    Science.gov (United States)

    Torres-Rendon, Jose Guillermo; Köpf, Marius; Gehlen, David; Blaeser, Andreas; Fischer, Horst; De Laporte, Laura; Walther, Andreas

    2016-03-14

    The merging of defined nanoscale building blocks with advanced additive manufacturing techniques is of eminent importance for the preparation of multiscale and highly functional materials with de novo designed hierarchical architectures. Here, we demonstrate that hydrogels of cellulose nanofibrils (CNF) can be processed into complex shapes, and used as a sacrificial template to prepare freestanding cell constructs. We showcase our approach for the fabrication of hollow fibers using a controlled extrusion through a circular die into a coagulation bath. The dimensions of the hollow fibers are tunable, and the final tubes combine the nanofibrillar porosity of the CNF hydrogel with a submillimeter wall thickness and centimeter-scale length provided by the additive manufacturing technique. We demonstrate that covalent and supramolecular cross-linking of the CNFs can be used to tailor the mechanical properties of the hydrogel tubes within 1 order of magnitude and in an attractive range for the mechanosensation of cells. The resulting tubes are highly biocompatible and allow for the growth of mouse fibroblasts into confluent cell layers in their inner lumen. A detailed screening of several cellulases enables degradation of the scaffolding, temporary CNF hydrogel tube in a quick and highly cell-friendly way, and allows the isolation of coherent cell tubes. We foresee that the growing capabilities of hydrogel printing techniques in combination with the attractive features of CNFs-sustainable, globally abundant, biocompatible and enzymatically degradable-will allow making plant-based biomaterials with hierarchical structures and on-demand degradation useful, for instance, to engineer complex tissue structures to replace animal models, and for implants. PMID:26812393

  16. Ion doping of surface layers in conducting electrical materials

    International Nuclear Information System (INIS)

    The presented article gives basic component elements of an implanter MKPCz-99, its parameters and methods for doping surface layers of conducting electrical materials. The discussed device makes possible to dope the materials with ions of gaseous elements. At the application of cones made of solid-element sheets it is possible to perform doping with atoms that do not chemically react with the modified material. By performing voltage drop measurements with a specialized circuit between a movable testing electrode and the modified sample the dependence of transition resistance on pressure force of the testing electrode on the sample can be determined. The testing can be performed at the current passage of a determined value for surfaces modified with ions of gaseous elements or atoms of solid elements. A computer stand for switch testing makes possible to measure temperature of switch contacts and voltage drop at the contact and thereby to determine contact resistance of a switch depending on the number of switch cycles (ON-OFF). Pattern recording of current and voltage at the switch contacts and the application of an adequate computer software makes possible to determined the value of energy between fixed and moving contacts at their getting apart. In order to eliminate action of the environment onto the switch operation measurements can be performed at placing the tested switch together with the driving system in an atmosphere of noble gas like argon. (authors)

  17. Theoretical Study of Layered Oxychalcogenides as Thermoelectric Materials

    Science.gov (United States)

    Funashima, Hiroki

    2015-03-01

    In order to restrain global warming and realize a sustainable global energy system, the researches of various energy resources are done. In these various energy resources, attracted technology is thermoelectric technology. Recently Layered oxychalcogenides has interesting properties useful for new type thermoelectric materials. Firstly, from DFT and DFPT calculations, we performed the electronic structure calculation and the thermal structure calculation about layered oxychalcogenides. In addition, we calculated thermoelectric properties Blotch-Boltzmann equation, semi-classically. We indicate the mechanism behind the high power factor from calculation about the transport properties. The key to understanding the power factor is that different effective masses contribute to different transport phenomena in the crystal. The discrepancy between the effective mass for the conductivity and the thermoelectric power showed that the conductivity and thermoelectric power are conveyed by electrons with different effective masses in the Brillouin zone. In point of view the thermal conductivity ?, we discuss the electronic part ?el from Bloch-Boltzmann equations, and ?ph from DFTP calculations.

  18. Layered cathode materials for lithium ion rechargeable batteries

    Science.gov (United States)

    Kang, Sun-Ho (Naperville, IL); Amine, Khalil (Downers Grove, IL)

    2007-04-17

    A number of materials with the composition Li.sub.1+xNi.sub..alpha.Mn.sub..beta.Co.sub..gamma.M'.sub..delta.O.sub.2-- zF.sub.z (M'=Mg,Zn,Al,Ga,B,Zr,Ti) for use with rechargeable batteries, wherein x is between about 0 and 0.3, .alpha. is between about 0.2 and 0.6, .beta. is between about 0.2 and 0.6, .gamma. is between about 0 and 0.3, .delta. is between about 0 and 0.15, and z is between about 0 and 0.2. Adding the above metal and fluorine dopants affects capacity, impedance, and stability of the layered oxide structure during electrochemical cycling.

  19. Advanced Lithium Ion Battery Materials Prepared with Atomic Layer Deposition

    Science.gov (United States)

    Cavanagh, Andrew S.

    As the world consumes the dwindling supply of fossil fuels, an alternative to gasoline powered vehicles will become necessary. Lithium ion batteries (LIBs) are emerging as the dominant power source for portable electronics, and are seen as a promising energy source in the development of electric vehicles. Current LIB technology is not well suited for vehicles, increases in the energy density, power density and durability are needed before LIB are ready for widespread use in electric vehicles. LiCoO2 and graphite are the dominant cathode and anode active materials, respectively in LIBs. On the cathode side, instabilities in LiCoO 2 can lead to the deterioration of the LIB. Decomposition of electrolyte on the graphite anode surface to form a solid-electrolyte interphase (SEI) consumes lithium from the cathode resulting in a lower battery capacity. Instabilities in the in the SEI can result in catastrophic battery failure. Previous studies have employed metal oxides films, typically grown with wet chemical techniques, to stabilize LiCoO2 and mitigate the formation of the SEI on graphite. The thicknesses of films grown with wet chemical techniques was typically 50--1000 A. In order to achieve higher power densities, the particle size of LIB active materials is being scaled down. As active materials get smaller the mass contribution of a protective film can become a significant fraction of the total mass. Atomic layer deposition (ALD) has been used to grow ultra thin films of Al2O3 on LiCoO2 and graphite. By altering the interaction between the active material and the battery electrolyte it was possible to improve the stability of both LiCoO2 and graphite electrodes in LIBs. In the case of graphite, the Al2O3 film may be thought of as an artificial SEI. During the initial charge-discharge cycle of a LIB, the electrolyte decomposes on the anode to form the SEI. The formation of the SEI is believed to prevent further decomposition of the electrolyte on the anode surface. The SEI contains electrolyte decomposition products including Li2CO3, Li2O, LiOH, LiF and R-OLi. In order to grow a truly artificial SEI on the graphite anode, i.e. grow a film that mimics the SEI that forms during charge-discharge cycling, new ALD chemistries for the growth of Li2CO3 and LiOH have been developed. The ALD of an artificial SEI layer may limit lithium loss and improve the capacity stability during charge-discharge cycles.

  20. Layer-by-layer analysis of hydrogen in structural materials on the base of reflected electron spectroscopy

    International Nuclear Information System (INIS)

    On the base of reflected electron spectroscopy the techniques of layer-by-layer analysis of hydrogen concentration in structural materials affected to thermonuclear plasma are developed. The given technique of nondestructive control may be used for analysis of thermonuclear reactor nodes and components connecting with plasma and for studying of hydrogen interaction with different materials using in hydrogen energetics. The program of statistical simulation of spectra of elastically reflected electrons from inhomogeneous media are created

  1. Estimation of stresses in layers of dentures relining materials

    Directory of Open Access Journals (Sweden)

    J. ?mudzki

    2008-03-01

    Full Text Available Purpose: Durability tests of materials relining dentures should be carried out in conditions reflecting the realloading that accompanies bite force transmission. The influence of geometry resulting from a denture foundationshape on real stresses in relining has not been so far found.Design/methodology/approach: Using FEM modeling, identified were the stress levels in relining layers inconditions reflecting biting loading for two opposite cases of bone foundation atrophy.Findings: The equivalent Huber-Mises` stresses have not reached their critical values, although tangentialstresses on the interfacial where relining is bonded with denture base have reached 440kPa, which, for some of thecommercial types of relining denotes the bonding strength.Research limitations/implications: The linear elastic mechanical characteristics were assumed. Hence,during further research, taken into account should be the stiffening of characteristics in the upper loadings range,which is typical for silicones.Practical implications: In case of a convex foundation the biggest danger will be caused by any bond defectsoccurring in the central area because in that area shear of bond has reached the highest values.Originality/value: Values of stresses components identified in this paper reflect the real shear conditions ofrelining bonding with denture base and might constitute a determinant for strength tests.

  2. Sacrificial bonds and hidden length in biomaterials -- a kinetic, constitutive description of strength and toughness in bone

    CERN Document Server

    Lieou, Charles K C; Carlson, Jean M

    2013-01-01

    Sacrificial bonds and hidden length in structural molecules account for the greatly increased fracture toughness of biological materials compared to synthetic materials without such structural features, by providing a molecular-scale mechanism for energy dissipation. One example is in the polymeric glue connection between collagen fibrils in animal bone. In this paper, we propose a simple kinetic model that describes the breakage of sacrificial bonds and the release of hidden length, based on Bell's theory. We postulate a master equation governing the rates of bond breakage and formation. This enables us to predict the mechanical behavior of a quasi-one-dimensional ensemble of polymers at different stretching rates. We find that both the rupture peak heights and maximum stretching distance increase with the stretching rate. In addition, our theory naturally permits the possibility of self-healing in such biological structures.

  3. Three-dimensional silicone microfluidic interconnection scheme using sacrificial wax filaments

    Science.gov (United States)

    Dharmatilleke, Saman; Henderson, H. Thurman; Bhansali, Shekhar; Ahn, Chong H.

    2000-08-01

    A very simple room-temperature procedure is presented herein for formation of true three-dimensionality of microplumbing in plastic (silicone elastomer in this case), by molding the plastic to simply encapsulate a pre-formed network of sacrificial wax threads or other connected wax configurations which are ultimately to become micro channels and cavities in the plastic motherboard. When these wax sacrificial areas are etched away with acetone, precise cavities, channels, and capillaries results with direct arbitrary three- dimensionality for the first time. This method leads also to a simple and effective external interconnect scheme where ordinary fused silica tubes may be press-fitted into the surface opening to withstand high pressure. This method may be extended for connection of multiple levels of silicone motherboards together using small sections of fused silica tubing, with no loss of stacking volume because of the lack of any connector lips or bosses. An array of micro channels having circular cross sections with diameters of 100, 150 and 200 microns were molded on silicone elastomer using wax thread. The wax thread was dissolved in acetone after the silicon elastometer became components (motherboards) while being able to control the channel lengths within the stacks as desired. Mixing chambers were also molded in a single silicone elastomer layer, because true three-dimensionality is trivially possible without the complexity of multi stacked lithography.

  4. Carbon and titanium based layers for wood-based material

    OpenAIRE

    W. Kaczorowski; D. Batory

    2008-01-01

    Purpose: The main purpose of this work was to work out the technology of manufacturing carbon and titanium based layers on the surfaces of sintered carbides machining edges used in furniture industry.Design/methodology/approach: A hybrid deposition system employing DC magnetron sputtering and radio frequency plasma assisted chemical vapour deposition (RF PACVD) in one reaction chamber was used to manufacture Ti:C gradient layers. For the laboratory investigation layers were deposited on sinte...

  5. Fabrication of Meso-Porous Sintered Metal Thin Films by Selective Etching of Silica Based Sacrificial Template

    OpenAIRE

    Ludovic F. Dumee; Fenghua She; Mikel Duke; Stephen Gray,; Peter Hodgson; Lingxue Kong

    2014-01-01

    Meso-porous metal materials have enhanced surface energies offering unique surface properties with potential applications in chemical catalysis, molecular sensing and selective separation. In this paper, commercial 20 nm diameter metal nano-particles, including silver and copper were blended with 7 nm silica nano-particles by shear mixing. The resulted powders were cold-sintered to form dense, hybrid thin films. The sacrificial silica template was then removed by selective etching in 12 wt% h...

  6. Bioactive gyroid scaffolds formed by sacrificial templating of nanocellulose and nanochitin hydrogels as instructive platforms for biomimetic tissue engineering.

    Science.gov (United States)

    Torres-Rendon, Jose Guillermo; Femmer, Tim; De Laporte, Laura; Tigges, Thomas; Rahimi, Khosrow; Gremse, Felix; Zafarnia, Sara; Lederle, Wiltrud; Ifuku, Shinsuke; Wessling, Matthias; Hardy, John G; Walther, Andreas

    2015-05-20

    A sacrificial templating process using lithographically printed minimal surface structures allows complex de novo geo-metries of delicate hydrogel materials. The hydrogel scaffolds based on cellulose and chitin nanofibrils show differences in terms of attachment of human mesenchymal stem cells, and allow their differentiation into osteogenic outcomes. The approach here serves as a first example toward designer hydrogel scaffolds viable for biomimetic tissue engineering. PMID:25833165

  7. Replication of optical MEMS structures in sol–gel materials

    OpenAIRE

    Obi, S.; Gale, M. T.; Kuoni, A.; De Rooij, Nicolaas F

    2010-01-01

    A replication method of fabrication for micro electro mechanical systems (MEMS) structures is presented, for use as an alternative to silicon processing. UV-curable ORMOCER® sol–gel is used as base material. The basic fabrication process involves deposition and patterning of a sacrificial spacer layer and a combined molding and photolithography step. This method allows creation of free-standing micro-mechanical elements with monolithic integration of high resolution micro-optical structures. ...

  8. Arhaeoastronomical analysis of Levinsadovka sacrificial complex (South Russia)

    CERN Document Server

    Vodolazhskaya, Larisa

    2013-01-01

    The article presents research data using arhaeoastronomical methods of Levinsadovka settlement sacrificial complex in Northern Black Sea coast. In this work, new method of accounting terrain elevations using topographic maps was developed in arhaeoastronomical studies. Calculations of azimuths of the sun and moon rise and set in the astronomically significant moments of the year were made and astronomical regularities in the organization of the sacrificial complex identified. Related to the moon directions, as the most dedicated, identified. Revealed that the stone tools and fragments, used as sacrifices, mark the direction to the northern minor standstill moonrise. A similar situation was found on two archaeological sites: in Bezymennoye II settlement South sanctuary and in Pustynka settlement religious building. Drawing on ethnographic and folklore data, it is concluded about semiotic connection of stone tools, found in these religious constructions, with the "thunderstones" and meteorites.

  9. PDMS as a sacrificial substrate for SU-8-based biomedical and microfluidic applications

    International Nuclear Information System (INIS)

    We describe a new fabrication process utilizing polydimethylesiloxane (PDMS) as a sacrificial substrate layer for fabricating free-standing SU-8-based biomedical and microfluidic devices. The PDMS-on-glass substrate permits SU-8 photo patterning and layer-to-layer bonding. We have developed a novel PDMS-based process which allows the SU-8 structures to be easily peeled off from the substrate after complete fabrication. As an example, a fully enclosed microfluidic chip has been successfully fabricated utilizing the presented new process. The enclosed microfluidic chip uses adhesive bonding technology and the SU-8 layers from 10 µm to 450 µm thick for fully enclosed microchannels. SU-8 layers as large as the glass substrate are successfully fabricated and peeled off from the PDMS layer as single continuous sheets. The fabrication results are supported by optical microscopy and profilometry. The peel-off force for the 120 µm thick SU-8-based chips is measured using a voice coil actuator (VCA). As an additional benefit the release step leaves the input and the output of the microchannels accessible to the outside world facilitating interconnecting to the external devices

  10. The effect of sacrificial bonds on the mechanical behavior of a single polymer chain - A Monte Carlo study

    International Nuclear Information System (INIS)

    Full text: Understanding the basic building principles of biological materials from a fundamental point of view is a necessary prerequisite for possible transfer of these principles to technology. The byssal thread is an especially fascinating material showing high toughness, stiffness and extensibility. The byssal thread is secreted by marine mussels to adhere to rocky substrates. Being covered with a hard coating providing wear resistance, it shows an extensibility of more than 100 % with the ability of self-healing. Experimental studies on this system suggest that the high extensibility is due to so called 'sacrificial bonds' (SBs). Sacrificial Bonds are weaker than the covalent bonds holding the structure together and they can thermally induced open and close reversibly. The SBs break before the covalent bond rupture, providing hidden length and allowing for efficient energy dissipation. By this effect the toughness of the structure is significantly enhanced. These findings motivate the following simple model. The basic unit is a linear, covalently bonded polymer chain. Some of the monomers (so called sticky sites) can additionally form sacrificial bonds. Starting from a collapsed chain cyclic loading experiments were mimicked by determination of load-displacement curves by calculation of the mean force exerted by the chain for several end-to-end distances. The effect of the density and of the arrangement (ordered, random) of sticky sites on the mechanical behavior of the chain was investigated. For sufficiently high sticky site densities a pronounced hysteresis between stretching and relaxing of the chain could be observed. (author)

  11. Evaluation of proton conductivity by random walk approach in MOFs and layered materials.

    Czech Academy of Sciences Publication Activity Database

    Konale, M.S.; Lin, C.H.; Patil, D.; Zima, Vt?zslav; Shimakawa, K.; Svoboda, Jan

    Mulhouse : Univ. Haute Alsace, 2014. [International Workshop on Layered Materials /5./. 27.08.2014-29.08.2014, Mulhouse] R&D Projects: GA ?R(CZ) GA14-13368S Institutional support: RVO:61389013 Keywords : layered materials * metal organic framework * impedance analysis Subject RIV: CA - Inorganic Chemistry

  12. Protective nitrided layers for the structural materials of thermonuclear reactors

    International Nuclear Information System (INIS)

    Application of protective coatings based on light elements having strong interatomic bonds is one of the most practical and promising methods of decreasing the rate of erosion (wear) of the first wall of thermonuclear reactors due to ion sputtering and blistering. We carried out experiments for determining the surface radiation resistance and hydrogen permeability of a steel having a protective nitrided layer. In order to develop the protective layer on the 08Kh18N10T steel, it was subjected to nitriding in a stream of high purity nitrogen at 10000C. The specimens having a nitride layer were bombarded simultaneously with helium and hydrogen ions; besides this, hydrogen permeability of the specimens having a zone of internal nitriding was studied

  13. A rational design of cosolvent exfoliation of layered materials by directly probing liquidsolid interaction

    OpenAIRE

    Halim, Udayabagya; Zheng, Chu Ran; Chen, Yu; Lin, Zhaoyang; Shan JIANG; Cheng, Rui; Huang, Yu; Duan, Xiangfeng

    2013-01-01

    Exfoliation of layered materials such as graphite and transition metal dichalcogenides into mono- or few-layers is of significant interest for both the fundamental studies and potential applications. Here we report a systematic investigation of the fundamental factors governing the liquid exfoliation process and the rational design of a cosolvent approach for the exfoliation of layered materials. We show that Youngs equation can be used to predict the optimal cosolvent concentration for the ...

  14. Laminated metal composite formed from low flow stress layers and high flow stress layers using flow constraining elements and making same

    Science.gov (United States)

    Syn, Chol K. (Moraga, CA); Lesuer, Donald R. (Livermore, CA)

    1995-01-01

    A laminated metal composite of low flow stress layers and high flow stress layers is described which is formed using flow constraining elements, preferably in the shape of rings, individually placed around each of the low flow stress layers while pressure is applied to the stack to bond the layers of the composite together, to thereby restrain the flow of the low flow stress layers from the stack during the bonding. The laminated metal composite of the invention is made by the steps of forming a stack of alternate layers of low flow stress layers and high flow stress layers with each layer of low flow stress material surrounded by an individual flow constraining element, such as a ring, and then applying pressure to the top and bottom surfaces of the resulting stack to bond the dissimilar layers together, for example, by compression rolling the stack. In a preferred embodiment, the individual flow constraining elements surrounding the layers of low flow stress material are formed of a material which may either be the same material as the material comprising the high flow stress layers, or have similar flow stress characteristics to the material comprising the high flow stress layers. Additional sacrificial layers may be added to the top and bottom of the stack to avoid damage to the stack during the bonding step; and these additional layers may then be removed after the bonding step.

  15. Sacrificial amphiphiles: Eco-friendly chemical herders as oil spill mitigation chemicals.

    Science.gov (United States)

    Gupta, Deeksha; Sarker, Bivas; Thadikaran, Keith; John, Vijay; Maldarelli, Charles; John, George

    2015-06-01

    Crude oil spills are a major threat to marine biota and the environment. When light crude oil spills on water, it forms a thin layer that is difficult to clean by any methods of oil spill response. Under these circumstances, a special type of amphiphile termed as "chemical herder" is sprayed onto the water surrounding the spilled oil. The amphiphile forms a monomolecular layer on the water surface, reducing the air-sea surface tension and causing the oil slick to retract into a thick mass that can be burnt in situ. The current best-known chemical herders are chemically stable and nonbiodegradable, and hence remain in the marine ecosystem for years. We architect an eco-friendly, sacrificial, and effective green herder derived from the plant-based small-molecule phytol, which is abundant in the marine environment, as an alternative to the current chemical herders. Phytol consists of a regularly branched chain of isoprene units that form the hydrophobe of the amphiphile; the chain is esterified to cationic groups to form the polar group. The ester linkage is proximal to an allyl bond in phytol, which facilitates the hydrolysis of the amphiphile after adsorption to the sea surface into the phytol hydrophobic tail, which along with the unhydrolyzed herder, remains on the surface to maintain herding action, and the cationic group, which dissolves into the water column. Eventual degradation of the phytol tail and dilution of the cation make these sacrificial amphiphiles eco-friendly. The herding behavior of phytol-based amphiphiles is evaluated as a function of time, temperature, and water salinity to examine their versatility under different conditions, ranging from ice-cold water to hot water. The green chemical herder retracted oil slicks by up to ~500, 700, and 2500% at 5, 20, and 35C, respectively, during the first 10 min of the experiment, which is on a par with the current best chemical herders in practice. PMID:26601197

  16. Sacrificial amphiphiles: Eco-friendly chemical herders as oil spill mitigation chemicals

    Science.gov (United States)

    Gupta, Deeksha; Sarker, Bivas; Thadikaran, Keith; John, Vijay; Maldarelli, Charles; John, George

    2015-01-01

    Crude oil spills are a major threat to marine biota and the environment. When light crude oil spills on water, it forms a thin layer that is difficult to clean by any methods of oil spill response. Under these circumstances, a special type of amphiphile termed as chemical herder is sprayed onto the water surrounding the spilled oil. The amphiphile forms a monomolecular layer on the water surface, reducing the airsea surface tension and causing the oil slick to retract into a thick mass that can be burnt in situ. The current best-known chemical herders are chemically stable and nonbiodegradable, and hence remain in the marine ecosystem for years. We architect an eco-friendly, sacrificial, and effective green herder derived from the plant-based small-molecule phytol, which is abundant in the marine environment, as an alternative to the current chemical herders. Phytol consists of a regularly branched chain of isoprene units that form the hydrophobe of the amphiphile; the chain is esterified to cationic groups to form the polar group. The ester linkage is proximal to an allyl bond in phytol, which facilitates the hydrolysis of the amphiphile after adsorption to the sea surface into the phytol hydrophobic tail, which along with the unhydrolyzed herder, remains on the surface to maintain herding action, and the cationic group, which dissolves into the water column. Eventual degradation of the phytol tail and dilution of the cation make these sacrificial amphiphiles eco-friendly. The herding behavior of phytol-based amphiphiles is evaluated as a function of time, temperature, and water salinity to examine their versatility under different conditions, ranging from ice-cold water to hot water. The green chemical herder retracted oil slicks by up to ~500, 700, and 2500% at 5, 20, and 35C, respectively, during the first 10 min of the experiment, which is on a par with the current best chemical herders in practice. PMID:26601197

  17. Layered HydroxidePorphyrin Hybrid Materials: Synthesis, Structure, and Properties.

    Czech Academy of Sciences Publication Activity Database

    Demel, Jan; Lang, Kamil

    2012-01-01

    Ro?. 2012, ?. 32 (2012), s. 5154-5164. ISSN 1434-1948 R&D Projects: GA ?R GAP207/10/1447 Institutional support: RVO:61388980 Keywords : layered compounds * intercalations * porphyrinoids * phthalocyanines * singlet oxygen Subject RIV: CA - Inorganic Chemistry Impact factor: 3.120, year: 2012

  18. Layered materials with improved magnesium intercalation for rechargeable magnesium ion cells

    Science.gov (United States)

    Doe, Robert Ellis; Downie, Craig Michael; Fischer, Christopher; Lane, George Hamilton; Morgan, Dane; Nevin, Josh; Cedar, Gerbrand; Persson, Kristin Aslaug; Eaglesham, David

    2015-11-05

    Electrochemical devices which incorporate cathode materials that include layered crystalline compounds for which a structural modification has been achieved which increases the diffusion rate of multi-valent ions into and out of the cathode materials. Examples in which the layer spacing of the layered electrode materials is modified to have a specific spacing range such that the spacing is optimal for diffusion of magnesium ions are presented. An electrochemical cell comprised of a positive intercalation electrode, a negative metal electrode, and a separator impregnated with a nonaqeuous electrolyte solution containing multi-valent ions and arranged between the positive electrode and the negative electrode active material is described.

  19. Layered materials with improved magnesium intercalation for rechargeable magnesium ion cells

    Energy Technology Data Exchange (ETDEWEB)

    Doe, Robert Ellis; Downie, Craig Michael; Fischer, Christopher; Lane, George Hamilton; Morgan, Dane; Nevin, Josh; Ceder, Gerbrand; Persson, Kristin Aslaug; Eaglesham, David

    2015-10-27

    Electrochemical devices which incorporate cathode materials that include layered crystalline compounds for which a structural modification has been achieved which increases the diffusion rate of multi-valent ions into and out of the cathode materials. Examples in which the layer spacing of the layered electrode materials is modified to have a specific spacing range such that the spacing is optimal for diffusion of magnesium ions are presented. An electrochemical cell comprised of a positive intercalation electrode, a negative metal electrode, and a separator impregnated with a nonaqeuous electrolyte solution containing multi-valent ions and arranged between the positive electrode and the negative electrode active material is described.

  20. Layered materials with improved magnesium intercalation for rechargeable magnesium ion cells

    Energy Technology Data Exchange (ETDEWEB)

    Doe, Robert E.; Downie, Craig M.; Fischer, Christopher; Lane, George H.; Morgan, Dane; Nevin, Josh; Ceder, Gerbrand; Persson, Kristin A.; Eaglesham, David

    2016-01-19

    Electrochemical devices which incorporate cathode materials that include layered crystalline compounds for which a structural modification has been achieved which increases the diffusion rate of multi-valent ions into and out of the cathode materials. Examples in which the layer spacing of the layered electrode materials is modified to have a specific spacing range such that the spacing is optimal for diffusion of magnesium ions are presented. An electrochemical cell comprised of a positive intercalation electrode, a negative metal electrode, and a separator impregnated with a nonaqueous electrolyte solution containing multi-valent ions and arranged between the positive electrode and the negative electrode active material is described.

  1. Layer-by-layer polyelectrolyte deposition: a mechanism for forming biocomposite materials

    OpenAIRE

    Tan, YerPeng; Yildiz, Umit Hakan; Wei, Wei; Waite, J. Herbert; Miserez, Ali

    2013-01-01

    Complex coacervates prepared from poly-Aspartic acid (polyAsp) and poly-L-Histidine (polyHis) were investigated as models of the metastable protein phases used in the formation of biological structures such as squid beak. When mixed, polyHis and polyAsp form coacervates whereas poly-L-Glutamic acid (polyGlu) forms precipitates with polyHis. Layer-by-layer (LbL) structures of polyHis-polyAsp on gold substrates were compared with those of precipitate-forming polyHis-polyGlu by monitoring with i...

  2. A rational design of cosolvent exfoliation of layered materials by directly probing liquid-solid interaction.

    Science.gov (United States)

    Halim, Udayabagya; Zheng, Chu Ran; Chen, Yu; Lin, Zhaoyang; Jiang, Shan; Cheng, Rui; Huang, Yu; Duan, Xiangfeng

    2013-01-01

    Exfoliation of layered materials such as graphite and transition metal dichalcogenides into mono- or few-layers is of significant interest for both the fundamental studies and potential applications. Here we report a systematic investigation of the fundamental factors governing the liquid exfoliation process and the rational design of a cosolvent approach for the exfoliation of layered materials. We show that Young's equation can be used to predict the optimal cosolvent concentration for the effective exfoliation of graphite and molybdenum disulphide in water mixtures with methanol, ethanol, isopropanol and t-butyl alcohol. Moreover, we find that the cosolvent molecular size has an important role in the exfoliation yield, attributed to the larger steric repulsion provided by the larger cosolvent molecules. Our study provides critical insight into the exfoliation of layered materials, and defines a rational strategy for the design of an environmentally friendly pathway to the high yield exfoliation of layered materials. PMID:23896793

  3. Electrical Transport of Field-Effect Transistors Based on CVD Grown Two-Dimensional Layered Materials

    Science.gov (United States)

    Lin, Ming-Wei; Li, Xufan; Wang, Kai; Puretzky, Alexander; Rouleau, Christopher; Geohegan, David; Xiao, Kai; CNMS, ORNL Team

    2015-03-01

    By changing the layer numbers, the electrical transport of field effect transistors based on CVD grown two-dimensional (2D) layered materials of transition metal dichalcongenides (TMDCs) such as MoSe2, WSe2 and WS2 shown the different characteristics will be demonstrated. The transport measurements show that the altered semiconductor characteristics of these 2D materials can be possibly attributed to the shift of Fermi level when changing the number of layers. Besides, the transport characteristics can be tuned by adjusting the W/Mo doping level and mobility is also increased with increasing the layer numbers. In addition, the annealing effect on these CVD grown 2D layered materials will be discussed. This work is conducted at the Center for Nanophase Materials Sciences, which is sponsored at Oak Ridge National Laboratory by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy.

  4. Shrinking device realized by using layered structures of homogeneous isotropic materials

    International Nuclear Information System (INIS)

    We propose the practical realization of a shrinking device by using layered structures of homogeneous isotropic materials. By mimicking the shrinking device with concentric alternating thin layers of isotropic dielectrics, the permittivity and the permeability in each isotropic layer can be properly determined from the effective medium theory in order to achieve the shrinking effect. The device realized by multilayer coating with dielectrics is validated by TE wave simulation, and good shrinking performance is demonstrated with only a few layers of homogeneous isotropic materials. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  5. Fabrication of sacrificial anode cathodic protection through casting method

    International Nuclear Information System (INIS)

    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)

  6. Tribological and Wear Properties of Multi-Layered Materials

    Directory of Open Access Journals (Sweden)

    V. Bria

    2011-09-01

    Full Text Available The usage of fabrics as reinforcements in composites is spreading due to fabrics properties. The use of fabrics allows obtaining of sinuous surfaces, for instance, unlike the use of prepregs. Using fabrics as reinforcements it is also possible to obtain laminate-like materials having the same matrix in all their volume. In the case of pre-pregs usage always it is necessary to discuss about the bonding between individual plies. For this study eight materials were formed. The forming method consisted in placing the pre-polymer imbued fabric pieces into a mould to obtain plates of composites. Two types of fabric were used: one simple type of untwisted tows of carbon fibres and the second one simple type of alternated untwisted tows of carbon and aramide fibres. Both fabrics were prepared in order to ensure the matrix adherence. The polymer matrix is realised from epoxy system EPIPHEN RE 4020 / EPIPHEN DE 4020 filled with clay and talc in equal amounts of 5% (weight ratio. The use of clay and talc were meant to improve the thermal dimensional stability of final materials. Tribological properties of formed materials were studied using pin-on-disk method with steel disk and pins made of materials. Both orientation of reinforcement fibres relative to friction direction were taken into account. Results are encouraging further studies in order to identify the best solution of forming a multi-component material with more than one designable property.

  7. A multifluid mix model for the layered incompressible materials

    International Nuclear Information System (INIS)

    In this paper, a model for the unstable mixing of n parallel or concentric incompressible fluid layers is proposed. The approach to constructing this model is pairwise, based on a known two incompressible fluid mixing model. The problem complexity increases significantly in going from two to three fluids, but the increase in complexity is relatively small thereafter. We present a detailed study of the n=3 problem, which displays all of the difficult modeling issues applicable to arbitrary n?3 while still being reasonably tractable.

  8. A multifluid mix model for the layered incompressible materials

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, B L; Sharp, D H [Los Alamos National Laboratory, Los Alamos, NM 87544 (United States); Glimm, J; Yu, Y [Department of Applied Mathematics and Statistics, University at Stony Brook, Stony Brook, NY 11794-3600 (United States)], E-mail: bcheng@lanl.gov

    2008-12-15

    In this paper, a model for the unstable mixing of n parallel or concentric incompressible fluid layers is proposed. The approach to constructing this model is pairwise, based on a known two incompressible fluid mixing model. The problem complexity increases significantly in going from two to three fluids, but the increase in complexity is relatively small thereafter. We present a detailed study of the n=3 problem, which displays all of the difficult modeling issues applicable to arbitrary n{>=}3 while still being reasonably tractable.

  9. Layered packaging: A synergistic method of transporting radioactive material

    International Nuclear Information System (INIS)

    The DOE certification for a transportation cask used to ship radioactive Krypton 85 from the Idaho Chemical Processing Plant (ICPP) to Oak Ridge National Laboratory (ORNL), was allowed to expire in 1987. The Westinghouse Idaho Nuclear Company (WINCO) was charged by DOE with modifying this cask to meet all current NRC requirements and preparing an updated Safety Analysis Report for Packaging, which would be submitted by DOE to the NRC for certification. However, an urgent need arose for ORNL to receive Krypton 85 which was in storage at the ICPP, which would not allow time to obtain certification of the modified shipping cask. WINCO elected to use a layered shipping configuration in which the gaseous Krypton 85 was placed in the uncertified, modified shipping cask to make use of its shielding and thermal insulation properties. This cask was then inserted into the Model No. 6400 (Super Tiger) packaging using a specially constructed plywood box and polyurethane foam dunnage. Structural evaluations were completed to assure the Super Tiger would provide the necessary impact, puncture, and thermal protection during maximum credible accidents. Analyses were also completed to determine the uncertified Krypton shipping cask would provide the necessary containment and shielding for up to 3.7 E+14 Bq of Krypton 85 when packaged inside the Super Tiger. The resulting reports, based upon this layered packaging concept, were adequate to first obtain DOE certification for several restricted shipments of Krypton 85 and then NRC certification for unrestricted shipments

  10. Radionuclide separations using pillared layered materials. Final report

    International Nuclear Information System (INIS)

    The objective of this project is to prepare an all inorganic strontium specific sorbent or ion exchanger for the removal of highly alkaline nuclear waste solutions. A series of clays and layered titanates were pillared and calcined to convert their essentially two dimensional structure to three dimensional porous structures with high surface areas. The pillaring agents were alumina, zirconia, chromia and silica based. The pillared clays, particularly those containing Zr pillars, achieved moderate (Kd as high at 13,700 ml/g with V:m = 28) selectivities for Sr2+. In contrast, the silica pillared titanates showed exceptional affinities for Sr2+ with Kd values in excess of 100,000 ml/g in 5M NaNO3 + 1M NaOH. These latter results suggest a more detailed study of the pillared titanates in the presence of simulants closely resembling real waste solutions

  11. Magnetization and Electronic Structure of FeAs Layered Material

    International Nuclear Information System (INIS)

    Magnetic induction in the superconductor (B=H +4?M) in the zero field cooled samples (ZFC) is not equal to zero. Depending upon the chemical environment it has negative value in some and positive values in some others. In the field cooled samples, the magnetization becomes paramagnetic. We have calculated the band structure of one layer of FeAs lattice with spin polarized as well as unpolarized orbitals as a function of doping by Li atoms. For n number of Li atoms (n=0, 1,..., 4), we calculated the band gap at all of the k-points as well as the Fermi energy. The reduced normal state gap was found to lead to superconductivity. (author)

  12. Standard test method for laboratory evaluation of magnesium sacrificial anode test specimens for underground applications

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1997-01-01

    1.1 This test method covers a laboratory procedure that measures the two fundamental performance properties of magnesium sacrificial anode test specimens operating in a saturated calcium sulfate, saturated magnesium hydroxide environment. The two fundamental properties are electrode (oxidation potential) and ampere hours (Ah) obtained per unit mass of specimen consumed. Magnesium anodes installed underground are usually surrounded by a backfill material that typically consists of 75 % gypsum (CaSO42H2O), 20 % bentonite clay, and 5 % sodium sulfate (Na2SO4). The calcium sulfate, magnesium hydroxide test electrolyte simulates the long term environment around an anode installed in the gypsum-bentonite-sodium sulfate backfill. 1.2 This test method is intended to be used for quality assurance by anode manufacturers or anode users. However, long term field performance properties may not be identical to property measurements obtained using this laboratory test. Note 1Refer to Terminology G 15 for terms used ...

  13. Scanning tunnelling microscopy observations of biomolecules on layered materials.

    Science.gov (United States)

    Jungblut, H; Campbell, S A; Giersig, M; Mller, D J; Lewerenz, H J

    1992-01-01

    Scanning tunnelling microscopy (STM) has been performed on the reverse transcriptases of the human immunodeficiency virus (HIV-1) and the moloney murine leukaemia virus (MuLV). The biological molecules are adsorbed on n-type semiconducting MoTe2. The p66 (66 kD) subunit of the RT of HIV-1 is imaged by STM. Both STM and processed transmission electron microscopy (TEM) data show a spherical and horseshoe-like shape of external diameter ca. 65 A, depending on the angle of observation. The STM results show a larger diameter which is related to the curvature radius of the tip of the probing needle. The RTs of HIV-1 and MuLV exhibit a circular hole of ca. 20 A diameter in accordance with structure predictions and functioning considerations. The surface-molecule interaction is discussed in terms of the electronic properties of the semiconductor surface including the influence of small defect sites at the layered crystal surface. PMID:1285040

  14. Teo-iconologa del poder sacrificial entre los mochica Teo-iconology of sacrificial power among the Moche

    Directory of Open Access Journals (Sweden)

    Adolfo Chaparro Amaya

    2011-12-01

    Full Text Available Partiendo de las evidencias icnicas del rasgo predatorio y sus equivalentes narrativos presentes en diferentes piezas de la cultura mochica, el texto busca establecer (i una metodologa de aproximacin al sacrificio canbal que tenga en cuenta diversas formas icnicas de escritura, y (ii una explicacin so-ciocsmica de la poltica sacrificial. Al articular lo escritural y lo poltico, es posible aportar una nueva perspectiva a la rica discusin que sobre las relaciones entre canibalismo y poder han venido proponiendo los arquelogos, los semiticos y los antroplogos de las culturas prehispnicas.Based on the iconographic evidences of predation and their narrative equivalents, present in different aspects of the Mochica culture, this essay seeks to establish (i a methodology for approaching the cannibal sacrifice taking into account different forms of iconic writing; and (ii establish a socio-cosmic explanation to sacrificial politics. By articulating these scriptural and political aspects, the paper will provide a new perspective to the rich discussion on the relationship between cannibalism and power that has been proposed by archaeologists, anthropologists and studies on the semiotic of Prehispanic cultures.

  15. Geologic Evolution of Mars' North Polar Layered Deposits and Related Materials from Mars Odyssey THEMIS

    Science.gov (United States)

    Vasavada, A. R.; Richardson, M. I.; Byrne, S.; Ivanov, A. B.; Christensen, P. R.

    2003-01-01

    The presence of a thick sequence of horizontal layers of ice-rich material at Mars north pole, dissected by troughs and eroding at its margins, is undoubtedly telling us something about the evolution of Mars climate we just don't know what yet. The North Polar Layered Deposits (NPLD) most likely formed as astronomically driven climate variations led to the deposition of conformable, areally extensive layers of ice and dust over the polar region. More recently, the balance seems to have fundamentally shifted to net erosion, as evidenced by the many troughs within the NPLD and the steep, arcuate scarps present near its margins, both of which expose layering.

  16. Crystallographic dependence of the lateral undercut wet etch rate of Al0.5In0.5P in diluted HCl for III-V sacrificial release

    OpenAIRE

    Ansbk, Thor; Semenova, Elizaveta; Yvind, Kresten; Hansen, Ole

    2013-01-01

    The authors investigated the use of InAlP as a sacrificial layer lattice-matched to GaAs when diluted hydrochloric acid is used for sacrificial etching. They show that InAlP can be used to fabricate submicrometer air gaps in micro-opto-electro-mechanical systems and that a selectivity toward GaAs larger than 500 is achieved. This selectivity enables fabrication control of the nanometer-size structures required in photonic crystal and high-index contrast subwavelength grating structures. The c...

  17. TiO?/ZnO inner/outer double-layer hollow fibers for improved detection of reducing gases.

    Science.gov (United States)

    Katoch, Akash; Kim, Jae-Hun; Kim, Sang Sub

    2014-12-10

    TiO2/ZnO double-layer hollow fibers (DLHFs) are proposed as a superior sensor material in comparison to regular single-layer hollow fibers (HFs) for the detection of reducing gases. DLHFs were synthesized on sacrificial polymer fibers via atomic layer deposition of a first layer of TiO2 followed by a second layer of ZnO and by a final thermal treatment. The inner TiO2 receives electrons from the ZnO outer layer, which becomes more resistive due to the significant loss of electrons. This highly resistive ZnO layer partially regains its original resistivity when exposed to reducing gases such as CO, thus enabling more resistance variation in DLHFs. DLHFs are a novel material compared to HFs and can be successfully employed to fabricate chemical sensors for the accurate detection of reducing gases. PMID:25379680

  18. Anomalous elastic buckling of layered crystalline materials in the absence of structure slenderness

    Science.gov (United States)

    Ren, Manrui; Liu, Yilun; Zhe Liu, Jefferson; Wang, Lifeng; Zheng, Quanshui

    2016-03-01

    Layered crystalline materials, such as graphene, boron nitride, tungsten sulfate, phosphorene, etc., have attracted enormous attentions, due to their unique crystal structures and superior mechanical, thermal, and physical properties. Making use of mechanical buckling is a promising route to control their structural morphology and thus tune their physical properties, giving rise to many novel applications. In this paper, we employ molecular dynamics (MD) simulations and theoretical modeling to study the compressive buckling of a column made of layered crystalline materials with the crystal layers parallel to the compressive direction. We find that the mechanical buckling of the layered crystalline materials exhibits two anomalous and counter-intuitive features as approaching the zero slenderness ratio. First, the critical buckling strain ?cr has a finite value that is much lower than the material's elastic limit strain. A continuum mechanics model (by homogenizing the layered materials) is proposed for the ?cr, which agrees well with the results of MD simulations. We find that the ?cr solely depends on elastic constants without any structural dimension, which appears to be an intrinsic material property and thus is defined as intrinsic buckling strain (IBS), ?crIBS, in this paper. Second, below a certain nanoscale length, l0, in the compressive direction (e.g., about 20 nm for graphite), the critical buckling strain ?cr shows a size effect, i.e., increasing as the column length L decreases. To account for the size effect, inspired by our recently developed multi-beam shear model (Liu et al., 2011), a bending energy term of individual crystal layer is introduced in our continuum model. The theoretical model of ?cr agrees well with the size effects observed in MD simulations. This study could lay a ground for engineering layered crystalline materials in various nano-materials and nano-devices via mechanical buckling.

  19. A estrutura sacrificial do compadrio: uma ontologia da desigualdade?

    Directory of Open Access Journals (Sweden)

    Marcos Lanna

    2009-01-01

    It is shown that god-parenthood is not only a religious or kinship institution and that it does not reinforce inequalities that supposedly pre-exist it, but rather it is a structure that generates inequalities. God-parenthood is understood as a structure by the description of reciprocity circuits. Understood as the circulation of a child from biological towards spiritual parents, to be returned by "grace", it implies asymmetries and inequalities. It also evokes the ontology of the social, founded on non-mercantile values' circulation, and on what Sahlins (2008 designates "elementary structure of political life". It is shown that reciprocity is related to the sacrificial aspect of the child's gift, and also to other types of considerations, such as that present in the catholic vows. Finally, it is demonstrated the relevancy of this type of analysis for future understandings of other benefits and categories often taken as purely economic ones, such as "labor".

  20. Living bacterial sacrificial porogens to engineer decellularized porous scaffolds.

    Science.gov (United States)

    Xu, Feng; Sridharan, BanuPriya; Durmus, Naside Gozde; Wang, ShuQi; Yavuz, Ahmet Sinan; Gurkan, Umut Atakan; Demirci, Utkan

    2011-01-01

    Decellularization and cellularization of organs have emerged as disruptive methods in tissue engineering and regenerative medicine. Porous hydrogel scaffolds have widespread applications in tissue engineering, regenerative medicine and drug discovery as viable tissue mimics. However, the existing hydrogel fabrication techniques suffer from limited control over pore interconnectivity, density and size, which leads to inefficient nutrient and oxygen transport to cells embedded in the scaffolds. Here, we demonstrated an innovative approach to develop a new platform for tissue engineered constructs using live bacteria as sacrificial porogens. E.coli were patterned and cultured in an interconnected three-dimensional (3D) hydrogel network. The growing bacteria created interconnected micropores and microchannels. Then, the scafold was decellularized, and bacteria were eliminated from the scaffold through lysing and washing steps. This 3D porous network method combined with bioprinting has the potential to be broadly applicable and compatible with tissue specific applications allowing seeding of stem cells and other cell types. PMID:21552485

  1. An advanced tunnel oxide layer process for 65 nm NOR floating-gate flash memories

    Science.gov (United States)

    Chiu, Shengfen; Xu, Yue; Ji, Xiaoli; Liao, Yiming; Wu, Fuwei; Yan, Feng

    2015-10-01

    An advanced tunnel oxide layer process for 65 nm NOR-type floating-gate flash memory is proposed to improve tunnel oxide quality by an additive sacrificial oxide layer growth. The sacrificial oxide layer process effectively controls the thickness variation of tunnel oxide and improves the flatness of the SiO2/Si interface across the active area. The interface traps generation during program/erase cycling of flash cells is found to be reduced, and the reliability property is significantly improved as compared to flash cells without the sacrificial oxide layer process. The technology is applicable to further scaled floating-gate flash memories.

  2. The correlation of layer waviness defect on compression strength of carbon fiber composite material

    International Nuclear Information System (INIS)

    As advanced composite materials having superior physical and mechanical properties are being developed, optimization of their production process is eagerly being sought. One of the most common defects in production of structural composites is layer waviness. Layer waviness is more pronounced in thick section flat and cylindrical laminates that are extensively used in missile casings. Submersibles and space platforms. Layer waviness undulates the entire layer of a multidirectional laminate in through-the-thickness direction leading to gross deterioration of its compression strength. This research investigates the influence of multiple layer waviness in a double nest formation on the compression strength of a composite laminate. Different wave fractions of wavy 0 degree layer were fabricated in IM/855 1- 7 carbon- epoxy composite laminate on a steel mold using single step fabrication procedure. The laminate was cured on a heated press according to specific curing cycle. Static compression testing was performed using short block compression fixture on an universal testing machine. The purpose of these tests was to determine the effects of multiple layer wave regions on the compression strength of composite laminate. The experimental and analytical results revealed that up to about 35% fraction of wavy 0 degree layers. The reduction in compression strength of composite laminate was constant after fraction of wavy 0 degree layers exceeded 35%. This analysis indicated that the percentage of 0 degree wavy layer may be used to estimate the reduction in compression strength of a composite laminate under restricted conditions. (author)

  3. Type II strained layer superlattice: a potential infrared sensor material for space

    Science.gov (United States)

    Zheng, L.; Tidrow, M. Z.; Novello, A.; Weichel, H.; Vohra, S.

    2008-02-01

    The Missile Defense Agency's Advanced Technology Office is developing advanced passive electro-optical and infrared sensors for future space-based seekers by exploring new infrared detector materials. A Type II strained layer superlattice, one of the materials under development, has shown great potential for space applications. Theoretical results indicate that strained layer superlattice has the promise to be superior to current infrared sensor materials, such as HgCdTe, quantum well infrared photodetectors, and Si:As. Strained layer superlattice-based infrared detector materials combine the advantages of HgCdTe and quantum well infrared photodetectors. The bandgap of strained layer superlattice can be tuned for strong broadband absorption throughout the short-, mid-, long-, and very long wavelength infrared bands. The electronic band structure can be engineered to suppress Auger recombination noise and reduce the tunneling current. The device structures can be easily stacked for multicolor focal plane arrays. The III-V semiconductor fabrication offers the potential of producing low-defect-density, large-format focal plane arrays with high uniformity and high operability. A current program goal is to extend wavelengths to longer than 14 ?m for space applications. This paper discusses the advantages of strained layer superlattice materials and describes efforts to improve the material quality, device design, and device processing.

  4. Optimized cylindrical invisibility cloak with minimum layers of non-magnetic isotropic materials

    Energy Technology Data Exchange (ETDEWEB)

    Yu Zhenzhong; Feng Yijun; Xu Xiaofei; Zhao Junming; Jiang Tian, E-mail: yjfeng@nju.edu.cn [Department of Electronic Engineering, School of Electronic Science and Engineering, Nanjing University, Nanjing, 210093 (China)

    2011-05-11

    We present optimized design of cylindrical invisibility cloak with minimum layers of non-magnetic isotropic materials. Through an optimization procedure based on genetic algorithm, simpler cloak structure and more realizable material parameters can be achieved with better cloak performance than that of an ideal non-magnetic cloak with a reduced set of parameters. We demonstrate that a cloak shell with only five layers of two normal materials can result in an average 20 dB reduction in the scattering width for all directions when covering the inner conducting cylinder with the cloak. The optimized design can substantially simplify the realization of the invisibility cloak, especially in the optical range.

  5. Optimized cylindrical invisibility cloak with minimum layers of non-magnetic isotropic materials

    International Nuclear Information System (INIS)

    We present optimized design of cylindrical invisibility cloak with minimum layers of non-magnetic isotropic materials. Through an optimization procedure based on genetic algorithm, simpler cloak structure and more realizable material parameters can be achieved with better cloak performance than that of an ideal non-magnetic cloak with a reduced set of parameters. We demonstrate that a cloak shell with only five layers of two normal materials can result in an average 20 dB reduction in the scattering width for all directions when covering the inner conducting cylinder with the cloak. The optimized design can substantially simplify the realization of the invisibility cloak, especially in the optical range.

  6. Sacrificial adhesive bonding: a powerful method for fabrication of glass microchips

    Science.gov (United States)

    Lima, Renato S.; Leo, Paulo A. G. C.; Piazzetta, Maria H. O.; Monteiro, Alessandra M.; Shiroma, Leandro Y.; Gobbi, Angelo L.; Carrilho, Emanuel

    2015-08-01

    A new protocol for fabrication of glass microchips is addressed in this research paper. Initially, the method involves the use of an uncured SU-8 intermediate to seal two glass slides irreversibly as in conventional adhesive bonding-based approaches. Subsequently, an additional step removes the adhesive layer from the channels. This step relies on a selective development to remove the SU-8 only inside the microchannel, generating glass-like surface properties as demonstrated by specific tests. Named sacrificial adhesive layer (SAB), the protocol meets the requirements of an ideal microfabrication technique such as throughput, relatively low cost, feasibility for ultra large-scale integration (ULSI), and high adhesion strength, supporting pressures on the order of 5?MPa. Furthermore, SAB eliminates the use of high temperature, pressure, or potential, enabling the deposition of thin films for electrical or electrochemical experiments. Finally, the SAB protocol is an improvement on SU-8-based bondings described in the literature. Aspects such as substrate/resist adherence, formation of bubbles, and thermal stress were effectively solved by using simple and inexpensive alternatives.

  7. The influence of double nested layer waviness on compression strength of carbon fiber composite materials

    International Nuclear Information System (INIS)

    As advanced composite materials having superior physical and mechanical properties are being developed, optimization of their production processes in eagerly being sought. One of the most common defect in production of structural composites is layer waviness. Layer waviness is more pronounced in thick section flat and cylindrical laminates that are extensively used in missile casings, submersibles and space platforms. Layer waviness undulates the entire layers of a multidirectional laminate in through-the-thickness direction leading to gross deterioration of its compression strength. This research investigates the influence of multiple layer waviness in a double nest formation on the compression strength of a composite laminate. Different wave fractions of wave 0 degree centigrade layer fabricated in IM/85510-7 carbon - epoxy composite laminate on a steel mold using single step fabrication procedure. The laminate was cured on a heated press according to specific curing cycle. Static compression testing was performed using NASA short block compression fixture on an MTS servo Hydraulic machine. The purpose of these tests was to determine the effects of multiple layer wave regions on the compression strength of composite laminate. The experimental and analytical results revealed that up to about 35% fraction of wave 0 degree layer exceeded 35%. This analysis indicated that the percentage of 0 degree wavy layer may be used to estimate the reduction in compression strength of a composite laminate under restricted conditions. (author)

  8. Optimisation of the material properties of indium tin oxide layers for use in organic photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Doggart, P.; Bristow, N.; Kettle, J., E-mail: j.kettle@bangor.ac.uk [School of Electronic Engineering, Bangor University, Dean St., Bangor, Gwynedd, Wales LL57 1UT (United Kingdom)

    2014-09-14

    The influence of indium tin oxide [(In{sub 2}O{sub 3}:Sn), ITO] material properties on the output performance of organic photovoltaic (OPV) devices has been modelled and investigated. In particular, the effect of altering carrier concentration (n), thickness (t), and mobility (μ{sub e}) in ITO films and their impact on the optical performance, parasitic resistances and overall efficiency in OPVs was studied. This enables optimal values of these parameters to be calculated for solar cells made with P3HT:PC{sub 61}BM and PCPDTBT:PC{sub 71}BM active layers. The optimal values of n, t and μ{sub e} are not constant between different OPV active layers and depend on the absorption spectrum of the underlying active layer material system. Consequently, design rules for these optimal values as a function of donor bandgap in bulk-heterojunction active layers have been formulated.

  9. Improvement of Cylindrical Cloak by Layered Structure of Homogeneous Isotropic Materials

    OpenAIRE

    Ding, Jun; Liu, Yang; Chenjiang GUO; Xu, Qian

    2009-01-01

    The perfect cylindrical cloak requires three spatial variant material parameters, which is very difficult to realize in practice [Science 312, 1780 (2006)]. The approach of realizing the electromagnetic cloaking by concentric layered structures instead of using the metamaterial was presented [Optics Express, Vol. 15, No. 18 (2007)]. We use the concentric layered structures to realize a simplified cylindrical cloak with improved parameters and an ideal cylindrical cloak with spatially invarian...

  10. Material properties and field-effect transistor characteristics of hybrid organic/graphene active layers

    Science.gov (United States)

    Ha, Tae-Jun; Lee, Jongho; Chowdhury, Sk. Fahad; Akinwande, Deji; Dodabalapur, Ananth

    2012-10-01

    We report on the material properties and device characteristics of field-effect transistors (FETs) consisting of hybrid mono-layer graphene/organic semiconductor active layers. By capping with selected organic and polymeric layers, transformation of the electronic characteristics of mono-layer graphene FETs was observed. The off-state current is reduced while the on-state current and field-effect mobility are either unaffected or increased after depositing ?-conjugated organic semiconductors. Significantly, capping mono-layer graphene FETs with fluoropolymer improved the on-off current ratio from 5 to 10 as well as increased the field-effect mobility by factor of two compared to plain graphene FETs. Removal of ?-conjugated organic semiconductors or fluoropolymer from graphene FETs results in a return to the original electronic properties of mono-layer graphene FETs. This suggests that weak reversible electronic interactions between graphene and ?-conjugated organic semiconductors/fluoropolymer favorably tune the material and electrical characteristics of mono-layer graphene.

  11. Heterostructures based on two-dimensional layered materials and their potential applications

    KAUST Repository

    Li, Ming-yang

    2015-12-04

    The development of two-dimensional (2D) layered materials is driven by fundamental interest and their potential applications. Atomically thin 2D materials provide a wide range of basic building blocks with unique electrical, optical, and thermal properties which do not exist in their bulk counterparts. The van der Waals interlayer interaction enables the possibility to exfoliate and reassemble different 2D materials into arbitrarily and vertically stacked heterostructures. Recently developed vapor phase growth of 2D materials further paves the way of directly synthesizing vertical and lateral heterojunctions. This review provides insights into the layered 2D heterostructures, with a concise introduction to preparative approaches for 2D materials and heterostructures. These unique 2D heterostructures have abundant implications for many potential applications.

  12. Analysis of Photothermal Characterization of Layered Materials: Design of Optimal Experiments

    Science.gov (United States)

    Cole, Kevin D.

    2003-01-01

    In this paper numerical calculations are presented for the steady-periodic temperature in layered materials and functionally-graded materials to simulate photothermal methods for the measurement of thermal properties. No laboratory experiments were performed. The temperature is found from a new Green s function formulation which is particularly well-suited to machine calculation. The simulation method is verified by comparison with literature data for a layered material. The method is applied to a class of two-component functionally-graded materials and results for temperature and sensitivity coefficients are presented. An optimality criterion, based on the sensitivity coefficients, is used for choosing what experimental conditions will be needed for photothermal measurements to determine the spatial distribution of thermal properties. This method for optimal experiment design is completely general and may be applied to any photothermal technique and to any functionally-graded material.

  13. Different materials as a cathode modification layer on the impact of organic solar cells

    Science.gov (United States)

    Zhong, Jian; Huang, Qiuyan; Yu, Junsheng; Jiang, Yadong

    2010-10-01

    Organic thin film solar cells based on conjugated polymer or small molecules have showed an interesting approach to energy conversion since Tang reported a single donor-accepter hetero-junction solar cell. The power conversion efficiency of organic solar cells has increased steadily over last decade. Small-molecular weight organic double heterojunction donor-acceptor layer organic solar cells (OSC) with a structure of indium-tin-oxide (ITO)/CuPc(200)/C60(400)/x/Ag(1000), using CuPc(copper Phthalocyanine)as donor layer, and Alq3(8-Hydroxyquinoline aluminum salt), BCP(Bromocresol purple sodium salt) and Bphen(4'7-diphyenyl-1,10-phenanthroline) as cathode modification layer, respectively were fabricated. The performance of OSC was studied as a function of the different materials as an cathode modification layer to optimize the structure. The current-voltage characteristic of the solar cell under AM1.5 solar illumination at an intensity of 100 mw/cm2 showed that the power conversion efficiency (PCE) was dependent of the different materials of the cathode modification layer. the efficiency along with the different materials as an cathode modification layer will diminish under that standard solar illumination(AM1.5)was obtained. Using a double heterostructure of ITO/CuPc(200)/C60(400)/Alq3(60)/Ag(1000) with high-vacuum evaporation technology, the efficiency was 0.587%.the efficiency was 0.967% when the material of the cathode modification layer was BCP, with the structure of ITO/CuPc(200)/C60(400)/BCP(35)/Ag(1000), and the efficiency was 0.742% when the material of the cathode modification layer was Bphen, with the structure of ITO/CuPc(200)/C60(400)/ Bphen(50)/Ag(1000).Using different materials as a cathode modification layer, it can be seen that the material which matches the energy level could even eventually be able to improve the energy conversion efficiency more.

  14. Antifouling and Antibacterial Multifunctional Polyzwitterion/Enzyme Coating on Silicone Catheter Material Prepared by Electrostatic Layer-by-Layer Assembly.

    Science.gov (United States)

    Vaterrodt, Anne; Thallinger, Barbara; Daumann, Kevin; Koch, Dereck; Guebitz, Georg M; Ulbricht, Mathias

    2016-02-01

    The formation of bacterial biofilms on indwelling medical devices generally causes high risks for adverse complications such as catheter-associated urinary tract infections. In this work, a strategy for synthesizing innovative coatings of poly(dimethylsiloxane) (PDMS) catheter material, using layer-by-layer assembly with three novel functional polymeric building blocks, is reported, i.e., an antifouling copolymer with zwitterionic and quaternary ammonium side groups, a contact biocidal derivative of that polymer with octyl groups, and the antibacterial hydrogen peroxide (H2O2) producing enzyme cellobiose dehydrogenase (CDH). CDH oxidizes oligosaccharides by transferring electrons to oxygen, resulting in the production of H2O2. The design and synthesis of random copolymers which combine segments that have antifouling properties by zwitterionic groups and can be used for electrostatically driven layer-by-layer (LbL) assembly at the same time were based on the atom-transfer radical polymerization of dimethylaminoethyl methacrylate and subsequent partial sulfobetainization with 1,3-propane sultone followed by quaternization with methyl iodide only or octyl bromide and thereafter methyl iodide. The alternating multilayer systems were formed by consecutive adsorption of the novel polycations with up to 50% zwitterionic groups and of poly(styrenesulfonate) as the polyanion. Due to its negative charge, enzyme CDH was also firmly embedded as a polyanionic layer in the multilayer system. This LbL coating procedure was first performed on prefunctionalized silicon wafers and studied in detail with ellipsometry as well as contact angle (CA) and zetapotential (ZP) measurements before it was transferred to prefunctionalized PDMS and analyzed by CA and ZP measurements as well as atomic force microscopy. The coatings comprising six layers were stable and yielded a more neutral and hydrophilic surface than did PDMS, the polycation with 50% zwitterionic groups having the largest effect. Enzyme activity was found to be dependent on the depth of embedment in the multilayer coating. Depending on the used polymeric building block, up to a 60% reduction in the amount of adhering bacteria and clear evidence for killed bacteria due to the antimicrobial functionality of the coating could be confirmed. Overall, this work demonstrates the feasibility of an easy to perform and shape-independent method for preparing an antifouling and antimicrobial coating for the significant reduction of biofilm formation and thus reducing the risk of acquiring infections by using urinary catheters. PMID:26766428

  15. Development of a Biocompatible Layer-by-Layer Film System Using Aptamer Technology for Smart Material Applications

    Directory of Open Access Journals (Sweden)

    Amanda Foster

    2014-05-01

    Full Text Available Aptamers are short, single-stranded nucleic acids that fold into well-defined three dimensional (3D structures that allow for binding to a target molecule with affinities and specificities that can rival or in some cases exceed those of antibodies. The compatibility of aptamers with nanostructures such as thin films, in combination with their affinity, selectivity, and conformational changes upon target interaction, could set the foundation for the development of novel smart materials. In this study, the development of a biocompatible aptamer-polyelectrolyte film system was investigated using a layer-by-layer approach. Using fluorescence microscopy, we demonstrated the ability of the sulforhodamine B aptamer to bind its cognate target while sequestered in a chitosan-hyaluronan film matrix. Studies using Ultraviolet-visible (UV-Vis spectrophotometry also suggest that deposition conditions such as rinsing time and volume play a strong role in the internal film interactions and growth mechanisms of chitosan-hyaluronan films. The continued study and development of aptamer-functionalized thin films provides endless new opportunities for novel smart materials and has the potential to revolutionize the field of controlled release.

  16. Two-dimensional nanosheets produced by liquid exfoliation of layered materials.

    OpenAIRE

    Coleman, JN; Lotya, M; O'Neill, A; Bergin, SD; King, PJ; Khan, U.; Young, K.; Gaucher, A; De, S; Smith, RJ; Shvets, IV; Arora, SK; Stanton, G; Kim, HY; Lee, K.

    2011-01-01

    If they could be easily exfoliated, layered materials would become a diverse source of two-dimensional crystals whose properties would be useful in applications ranging from electronics to energy storage. We show that layered compounds such as MoS(2), WS(2), MoSe(2), MoTe(2), TaSe(2), NbSe(2), NiTe(2), BN, and Bi(2)Te(3) can be efficiently dispersed in common solvents and can be deposited as individual flakes or formed into films. Electron microscopy strongly suggests that the material is exf...

  17. Investigation of Materials for Boundary Layer Control in a Supersonic Wind Tunnel

    Science.gov (United States)

    Braafladt, Alexander; Lucero, John M.; Hirt, Stefanie M.

    2013-01-01

    During operation of the NASA Glenn Research Center 15- by 15-Centimeter Supersonic Wind Tunnel (SWT), a significant, undesirable corner flow separation is created by the three-dimensional interaction of the wall and floor boundary layers in the tunnel corners following an oblique-shock/ boundary-layer interaction. A method to minimize this effect was conceived by connecting the wall and floor boundary layers with a radius of curvature in the corners. The results and observations of a trade study to determine the effectiveness of candidate materials for creating the radius of curvature in the SWT are presented. The experiments in the study focus on the formation of corner fillets of four different radii of curvature, 6.35 mm (0.25 in.), 9.525 mm (0.375 in.), 12.7 mm (0.5 in.), and 15.875 mm (0.625 in.), based on the observed boundary layer thickness of 11.43 mm (0.45 in.). Tests were performed on ten candidate materials to determine shrinkage, surface roughness, cure time, ease of application and removal, adhesion, eccentricity, formability, and repeatability. Of the ten materials, the four materials which exhibited characteristics most promising for effective use were the heavy body and regular type dental impression materials, the basic sculpting epoxy, and the polyurethane sealant. Of these, the particular material which was most effective, the heavy body dental impression material, was tested in the SWT in Mach 2 flow, and was observed to satisfy all requirements for use in creating the corner fillets in the upcoming experiments on shock-wave/boundary-layer interaction.

  18. Investigation of helium ions release processes from surface layer of lithium containing materials of fusion reactors

    International Nuclear Information System (INIS)

    Full text: The lithium-containing materials are considered as materials, which can be used to solve many pressing issues of creating fusion reactor. Each of these materials has its own specific advantages and disadvantages, but they have in common the ability of realization of the nuclear reactions on lithium isotopes to produce tritium and helium. All the data on the release of helium ions from the surface layer of lithium-containing materials under reactor irradiation were analyzed. To explain the effect of the intensive release of helium ions the experiments with different cooling rates of lead-lithium eutectics were performed

  19. Mixed-layered bismuth--oxygen--iodine materials for capture and waste disposal of radioactive iodine

    Science.gov (United States)

    Krumhansl, James L; Nenoff, Tina M

    2015-01-06

    Materials and methods of synthesizing mixed-layered bismuth oxy-iodine materials, which can be synthesized in the presence of aqueous radioactive iodine species found in caustic solutions (e.g. NaOH or KOH). This technology provides a one-step process for both iodine sequestration and storage from nuclear fuel cycles. It results in materials that will be durable for repository conditions much like those found in Waste Isolation Pilot Plant (WIPP) and estimated for Yucca Mountain (YMP). By controlled reactant concentrations, optimized compositions of these mixed-layered bismuth oxy-iodine inorganic materials are produced that have both a high iodine weight percentage and a low solubility in groundwater environments.

  20. Formation of a screening layer under irradiation of solid materials by power plasma flows

    International Nuclear Information System (INIS)

    The dynamics of the target plasma, formed by irradiation of solid-state materials by high-temperature currents of hydrogen plasma with the power density of W ? 10 MW/cm2, is experimentally studied. Interaction of the plasma with the materials proceeded in the magnetic field, oriented perpendicular to the surface. Graphite, plexiglas, quartz, boron nitride, aluminium, stainless steel, copper, molybdenum, tungsten were used as the target material. It is shown that a dense layer (n > 1017 cm-3) of the target plasma, screening the surface from the direct impact of the plasma current, is formed during t = 1-2 ?s on the irradiated surface. The magnetic field limits the target plasma expansion across the power lines and establishes unidimensional hydrodynamical behavior of the plasma. The dynamics and parameters of the screening layer plasma essentially depend on the target materials

  1. Elastic properties of a material composed of alternating layers of negative and positive Poisson's ratio

    International Nuclear Information System (INIS)

    The theory of elasticity predicts a variety of phenomena associated with solids that possess a negative Poisson's ratio. The fabrication of metamaterials with a 'designed' microstructure that exhibit a Poisson's ratio approaching the thermodynamic limits of 1/2 and -1 increases the likelihood of realising these phenomena for applications. In this work, we investigate the properties of a layered composite, with alternating layers of materials with negative and positive Poisson's ratio approaching the thermodynamic limits. Using the finite element method to simulate uniaxial loading and indentation of a free standing composite, we observed an increase in the resistance to mechanical deformation above the average value of the two materials. Even though the greatest increase in stiffness is gained as the thermodynamic limits are approached, a significant amount of added stiffness can be attained, provided that the Young's modulus of the negative Poisson's ratio material is not less than that of the positive Poisson's ratio material

  2. Mixed-layered bismuth-oxygen-iodine materials for capture and waste disposal of radioactive iodine

    Science.gov (United States)

    Krumhansl, James L; Nenoff, Tina M

    2013-02-26

    Materials and methods of synthesizing mixed-layered bismuth oxy-iodine materials, which can be synthesized in the presence of aqueous radioactive iodine species found in caustic solutions (e.g. NaOH or KOH). This technology provides a one-step process for both iodine sequestration and storage from nuclear fuel cycles. It results in materials that will be durable for repository conditions much like those found in Waste Isolation Pilot Plant (WIPP) and estimated for Yucca Mountain (YMP). By controlled reactant concentrations, optimized compositions of these mixed-layered bismuth oxy-iodine inorganic materials are produced that have both a high iodine weight percentage and a low solubility in groundwater environments.

  3. Nanotubes from Misfit Layered Compounds: A New Family of Materials with Low Dimensionality.

    Science.gov (United States)

    Panchakarla, Leela S; Radovsky, Gal; Houben, Lothar; Popovitz-Biro, Ronit; Dunin-Borkowski, Rafal E; Tenne, Reshef

    2014-11-01

    Nanotubes that are formed from layered materials have emerged to be exciting one-dimensional materials in the last two decades due to their remarkable structures and properties. Misfit layered compounds (MLC) can be produced from alternating assemblies of two different molecular slabs with different periodicities with the general formula [(MX)1+x]m[TX2]n (or more simply MS-TS2), where M is Sn, Pb, Bi, Sb, rare earths, T is Sn, Nb, Ta, Ti, V, Cr, and so on, and X is S, Se. The presence of misfit stresses between adjacent layers in MLC provides a driving force for curling of the layers that acts in addition to the elimination of dangling bonds. The combination of these two independent forces leads to the synthesis of misfit layered nanotubes, which are newcomers to the broad field of one-dimensional nanostructures and nanotubes. The synthesis, characterization, and microscopic details of misfit layered nanotubes are discussed, and directions for future research are presented. PMID:26278742

  4. Effect of biomolecules adsorption on oxide layers developed on metallic materials used in cooling water systems

    International Nuclear Information System (INIS)

    This thesis was carried out in the frame of the BIOCOR ITN European project, in collaboration with the industrial partner RSE S.p.A. (Italy). Metallic materials commonly used in cooling systems of power plants may be affected by bio-corrosion induced by biofilm formation. The objective of this work was to study the influence of biomolecules adsorption, which is the initial stage of biofilm formation, on the electrochemical behaviour and the surface chemical composition of three metallic materials (70Cu-30Ni alloy, 304L stainless steel and titanium) in seawater environments. In a first step, the interactions between a model protein, the bovine serum albumin (BSA), and the surface of these materials were investigated. Secondly, tightly bound (TB) and loosely bound (LB) extracellular polymeric substances (EPS), that play a fundamental role in the different stages of biofilm formation, maturation and maintenance, were extracted from Pseudomonas NCIMB 2021 marine strain, and their effects on oxide layers were also evaluated. For that purpose, electrochemical measurements (corrosion potential E(corr) vs time, polarization curves and electrochemical impedance spectroscopy (EIS)) performed during the very first steps of oxide layers formation (1 h immersion time) were combined to surface analysis by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ions mass spectrometry (ToF-SIMS). Compared to 70Cu-30Ni alloy in static artificial seawater (ASW) without biomolecules, for which a thick duplex oxide layer (outer redeposited Cu2O layer and inner oxidized nickel layer) is shown, the presence of BSA, TB EPS and LB EPS leads to a mixed oxide layer (oxidized copper and nickel) with a lower thickness. In the biomolecules-containing solutions, this oxide layer is covered by an adsorbed organic layer, mainly composed of proteins. A model is proposed to analyse impedance data obtained at E(corr). The results show a slow-down of the anodic reaction in the presence of biomolecules (BSA, TB EPS and LB EPS), and a corrosion inhibition effect by LB EPS and to a lesser extent by BSA. No detrimental effect is evidenced with TB EPS. On the other hand, the effect of TB EPS and BSA on the passivation behaviour of Ti in ASW and of 304L stainless steel in chloride-free solution was studied. From EIS data, resistivity profiles within oxide films can be plotted. For both materials, oxide layers are more protective with BSA and less protective with TB EPS compared to the solution without biomolecules. At last, biomolecules induce no significant differences in oxide layer composition and thickness. (author)

  5. Fatigue crack growth and fracture mechanics analysis of a working roll surface layer material

    OpenAIRE

    M. Drobne; Vuherer, T.; I. Samardi?; S Glode

    2014-01-01

    Fatigue crack growth and fracture mechanics analysis of a working roll surface layer material is presented in this paper. The research is done on a hot strip mill working roll where High Chromium Steel is used for rolls shell material. To obtain corresponding parameters, a rectangular single edge notched bend specimens SENB, according to standard BS 7448, were used. The fatigue crack growth analysis was done on a resonant testing machine with use of special crack gauges, while for fracture...

  6. Multi-layered Poly-Dimethylsiloxane As A Non-Hermetic Packaging Material For Medical MEMS

    OpenAIRE

    Lachhman, S.; Zorman, C.A.; Ko, W. H.

    2012-01-01

    Poly-dimethylsiloxane (PDMS) is an attractive material for packaging implantable biomedical microdevices owing to its biocompatibility, ease in application, and bio-friendly mechanical properties. Unfortunately, devices encapsulated by PDMS lack the longevity for use in chronic implant applications due to defect-related moisture penetration through the packaging layer. This paper describes an effort to improve the performance of PDMS as packaging material by constructing the encapsulant from ...

  7. Hybrid magnetic materials based on layered double hydroxides: from the chemistry towards the applications

    OpenAIRE

    Abellán Sáez, Gonzalo

    2014-01-01

    Layered double hydroxides (LDHs) are the leitmotiv of this dissertation. Contradicting the assertion that “any past was better”, LDHs have been continuously revisited from the middle of the twentieth century, and represent an excellent example of the never-ending beauty of Chemistry. New synthetic perspectives are giving a new impetus to LDH chemistry, which among hybrid materials, are finding their heyday. This is resulting in novel materials and also paving the way for new fundamental and p...

  8. Film of lignocellulosic carbon material for self-supporting electrodes in electric double-layer capacitors

    OpenAIRE

    Tsubasa Funabashi; Jun Mizuno; Masamichi Sato; Masao Kitajima; Makoto Matsuura; Shuichi Shoji

    2013-01-01

    A novel thin, wood-based carbon material with heterogeneous pores, film of lignocellulosic carbon material (FLCM), was successfully fabricated by carbonizing softwood samples of Picea jezoensis (Jezo spruce). Simultaneous increase in the specific surface area of FLCM and its affinity for electrolyte solvents in an electric double-layer capacitor (EDLC) were achieved by the vacuum ultraviolet/ozone (VUV/O3) treatment. This treatment increased the specific surface area of FLCM by 50% over that ...

  9. Suitability of Structural Aluminium Profiles as Sacrificial Anode for Carbon Steel

    OpenAIRE

    Iyiola O. OTUNNIYI; Daniel T. Oloruntoba

    2012-01-01

    The life of low carbon steels in many small scale structures can be remarkably prolonged by complementary sacrificial anode cathodic protection (SACP) but for constraints in availability of specialty anodes. Suitability of commonly available structural aluminium profiles as sacrificial anodes for low carbon steel has been investigated. Three different profiles were studied. Bare and coated steel samples were found to migrate clearly too cathodic potential regimes when coupled with the press-f...

  10. Efficiency of a Multi-Soil-Layering System on Wastewater Treatment Using Environment-Friendly Filter Materials

    OpenAIRE

    Ho, Chia-Chun; Wang, Pei-Hao

    2015-01-01

    The multi-soil-layering (MSL) system primarily comprises two parts, specifically, the soil mixture layer (SML) and the permeable layer (PL). In Japan, zeolite is typically used as the permeable layer material. In the present study, zeolite was substituted with comparatively cheaper and more environmentally friendly materials, such as expanded clay aggregates, oyster shells, and already-used granular activated carbon collected from water purification plants. A series of indoor tests indicated ...

  11. Preparation of textured layers of ferroelectric materials by means of high-frequency spraying technique

    International Nuclear Information System (INIS)

    The optimal conditions for producing the layers of multicomponent ferroelectrics oriented on an amorphous (glass) substrate by using the method of high-frequency sputtering of LiNbO3, LiTaO3 and BaTiO3 have been established. At the temperature of the substrate between 400 and 450 deg C and at sputtering rates from 20 to 35 A/min perfect textured layers of ferroelectrics for all these compounds have been obtained. The electrophysical and optical properties of layers of these materials with the film thickness from 0.4 to 0.7 have been studied. The most likely mechanism by which these layers are produced is discussed

  12. Struvite precipitation and phosphorus removal using magnesium sacrificial anode.

    Science.gov (United States)

    Kruk, Damian J; Elektorowicz, Maria; Oleszkiewicz, Jan A

    2014-04-01

    Struvite precipitation using magnesium sacrificial anode as the only source of magnesium is presented. High-purity magnesium alloy cast anode was found to be very effective in recovery of high-quality struvite from water solutions and from supernatant of fermented waste activated sludge from a wastewater treatment plant that does not practice enhanced biological phosphorus removal. Struvite purity was strongly dependent on the pH and the electric current density. Optimum pH of the 24 mM phosphorus and 46 mM ammonia solution (1:1.9 P:N ratio) was in the broad range between 7.5 and 9.3, with struvite purity exceeding 90%. Increasing the current density resulted in elevated struvite purity. No upper limits were observed in the studied current range of 0.05-0.2 A. Phosphorus removal rate was proportional to the current density and comparable for tests with water solutions and with the supernatant from fermented sludge. The highest P-removal rate achieved was 4.0 mg PO4-P cm(-2) h(-1) at electric current density of 45 A m(-2). Initial substrate concentrations affected the rate of phosphorus removal. The precipitated struvite accumulated in bulk liquid with significant portions attached to the anode surface from which regular detachment occurred. PMID:24387911

  13. Test of the material for radon seal layer at the mine waste disposal site Jazbec

    International Nuclear Information System (INIS)

    About 1.4 million t of mine waste was deposited at the mine waste disposal site Jazbec during the mining of ore at the Zirovski vrh uranium mine. The average concentration of uranium in the mine waste is about 60 g/t, the average specific activity of 226Ra is 730 Bq/m3. To reduce the radon exhalation rate and the penetration of rainfall water into the waste pile, it should be covered with an appropriate material. The surface of the waste pile is about 5 ha. The thickness of the cover should be about 2 m. A test field on the waste pile Jazbec (100 m long and 12-20 m wide) was constructed in 2003. The surface of the test field was separated into two parts: one part with a multi-layer cover (5 layers), the second part with only two layers. For the seal layer, fine clayey silt and sand were used. Measurements of radon exhalation were carried out on the mine waste material, on the seal layer, on the protection layer and finally on the humus layer. For the radon exhalation measurements, the method with charcoal absorbers was applied. The time of exposure was 48 h. The results of the radon exhalation rates confirmed that clayey silt and sand mixture is an adequate material to use as a radon barrier. The average results of the radon exhalation rates were 50% and more lower than the prescribed authorized limit of 0.1 Bqm2s-1. The results of the water penetration measurements were not as low as is required by the regulations. The improvement of clayey silt and sand characteristics with bentonite was also evaluated. (author)

  14. A fluorescent, photochromic and thermochromic trifunctional material based on a layered metal-viologen complex.

    Science.gov (United States)

    Wan, Fang; Qiu, Li-Xia; Zhou, Liang-Liang; Sun, Yan-Qiong; You, Yi

    2015-11-14

    The azide anion as an energy acceptor and an electron donor has been introduced into a metal-viologen compound to form a 2D layered viologen-based trifunctional material, which exhibits the rare discolored function of reversible photochromism and thermochromism. Interestingly, its fluorescence can be switched by visible light irradiation and heating in air. PMID:26445888

  15. Thermophysical Properties of Mars' North Polar Layered Deposits and Related Materials from Mars Odyssey THEMIS

    Science.gov (United States)

    Vasavada, A. R.; Richardson, M. I.; Byrne, S.; Ivanov, A. B.; Christensen, P. R.

    2003-01-01

    The presence of a thick sequence of horizontal layers of ice-rich material at Mars north pole, dissected by troughs and eroding at its margins, is undoubtedly telling us something about the evolution of Mars climate [1,2] we just don t know what yet. The North Polar Layered Deposits (NPLD) most likely formed as astronomically driven climate variations led to the deposition of conformable, areally extensive layers of ice and dust over the polar region. More recently, the balance seems to have fundamentally shifted to net erosion, as evidenced by the many troughs within the NPLD and the steep, arcuate scarps present near its margins, both of which expose layering. We defined a number of Regions of Interest ROI) for THEMIS to target as part of the Mars Odyssey Participating Scientist program. We use these THEMIS data in order to understand the morphology and color/thermal properties of the NPLD and related materials over relevant (i.e., m to km) spatial scales. We have assembled color mosaics of our ROIs in order to map the distribution of ices, the different layered units, dark material, and underlying basement. The color information from THEMIS is crucial for distinguishing these different units which are less distinct on Mars Orbiter Camera images. We wish to understand the nature of the marginal scarps and their relationship to the dark material. Our next, more ambitious goal is to derive the thermophysical properties of the different geologic materials using THEMIS and Mars Global Surveyor Thermal Emission Spectrometer TES) data.

  16. Film of lignocellulosic carbon material for self-supporting electrodes in electric double-layer capacitors

    Directory of Open Access Journals (Sweden)

    Tsubasa Funabashi

    2013-09-01

    Full Text Available A novel thin, wood-based carbon material with heterogeneous pores, film of lignocellulosic carbon material (FLCM, was successfully fabricated by carbonizing softwood samples of Picea jezoensis (Jezo spruce. Simultaneous increase in the specific surface area of FLCM and its affinity for electrolyte solvents in an electric double-layer capacitor (EDLC were achieved by the vacuum ultraviolet/ozone (VUV/O3 treatment. This treatment increased the specific surface area of FLCM by 50% over that of original FLCM. The results obtained in this study confirmed that FLCM is an appropriate self-supporting EDLC electrode material without any warps and cracks.

  17. Comparison of some coating techniques to fabricate barrier layers on packaging materials

    International Nuclear Information System (INIS)

    Atomic layer deposition (ALD), electron beam evaporation, magnetron sputtering and a sol-gel method were used to deposit thin aluminum oxide coatings onto two different fiber-based packaging materials of commercial board grades coated with synthetic and biodegradable polymers. Significant decreases in both the water vapor and oxygen permeation rates were observed. With each technique the barrier performance was improved. However, among the techniques tested ALD was found to be most suitable. Our results moreover revealed that biodegradable polylactic acid-coated paperboard with a 25-nm thick layer of aluminum oxide grown by ALD on top of it showed promising barrier characteristics against water vapor and oxygen.

  18. Metallic layered composite materials produced by explosion welding: Structure, properties, and structure of the transition zone

    Science.gov (United States)

    Mal'tseva, L. A.; Tyushlyaeva, D. S.; Mal'tseva, T. V.; Pastukhov, M. V.; Lozhkin, N. N.; Inyakin, D. V.; Marshuk, L. A.

    2014-10-01

    The structure, morphology, and microhardness of the transition zone in multilayer metallic composite joints are studied, and the cohesion strength of the plates to be joined, the mechanical properties of the formed composite materials, and fracture surfaces are analyzed. The materials to be joined are plates (0.1-1 mm thick) made of D16 aluminum alloy, high-strength maraging ZI90-VI (03Kh12N9K4M2YuT) steel, BrB2 beryllium bronze, and OT4-1 titanium alloy. Composite materials made of different materials are shown to be produced by explosion welding. The dependence of the interface shape (smooth or wavelike) on the physicomechanical properties of the materials to be joined is found. The formation of a wavelike interface is shown to result in the formation of intense-mixing regions in transition zones. Possible mechanisms of layer adhesion are discussed.

  19. Modelling of sacrificial spin-on glass (SOG) etching in non-straight microchannels using hydrofluoric acid

    Science.gov (United States)

    Hamzah, Azrul A.; Majlis, Burhanuddin Y.; Ahmad, Ibrahim

    2006-01-01

    This paper studies spin-on glass (SOG) etching in T-shaped microchannels by hydrofluoric acid (HF). Since oxide etching by HF in microchannels is both reaction and diffusion limited, an etching model based on non-first order chemical reaction/steady-state diffusion sacrificial layer etching mechanism is presented to compensate for the etching effect at channel junction. Microchannels are formed on silicon substrate by deep reactive ion etching (DRIE). Samples with channel depth varying from 1?m to 6 ?m are prepared by varying exposure time to reactant gas in DRIE chamber. Channel widths prior to the junction are varied from 2 ?m to 10 ?m while channel width beyond the junction is fixed at 5 ?m. The channels are then filled with SOG by multiple spin, bake and cure processes. After etchback planarization using 5% HF solution, the samples are coated with 1.5 ?m thick positive photoresist. An etch window is opened at channel fronts to expose underlying SOG. The samples are then time-etched in 5% HF solution and etch front propagation is observed under optical microscope through the transparent photoresist layer. It is observed that SOG etch rate in the microchannels is independent of channel width or channel depth. SOG etch rate at channel's T-junction is 0.67 times lower than etch rate in the straight channels preceding it due to HF concentration variation and etch product transfer rate variation effects. The proposed model fits experimental data well. Offset crosses vent pattern is determined as a good candidate for removing sacrificial oxide under an enclosed cap structure.

  20. Formation of nanocrystalline surface layers in various metallic materials by near surface severe plastic deformation

    Directory of Open Access Journals (Sweden)

    Masahide Sato, Nobuhiro Tsuji, Yoritoshi Minamino and Yuichiro Koizumi

    2004-01-01

    Full Text Available The surface of the various kinds of metallic materials sheets were severely deformed by wire-brushing at ambient temperature to achieve nanocrystalline surface layer. The surface layers of the metallic materials developed by the near surface severe plastic deformation (NS-SPD were characterized by means of TEM. Nearly equiaxed nanocrystals with grain sizes ranging from 30 to 200 nm were observed in the near surface regions of all the severely scratched metallic materials, which are Ti-added ultra-low carbon interstitial free steel, austenitic stainless steel (SUS304, 99.99 wt.%Al, commercial purity aluminum (A1050 and A1100, AlMg alloy (A5083, Al-4 wt.%Cu alloy, OFHC-Cu (C1020, CuZn alloy (C2600 and Pb-1.5%Sn alloy. In case of the 1050-H24 aluminum, the depth of the surface nanocrystalline layer was about 15 ?m. It was clarified that wire-brushing is an effective way of NS-SPD, and surface nanocrystallization can be easily achieved in most of metallic materials.

  1. The Influnece of Peat Layer on Hidrogen and Aluminium Concentration Originating from the Substratum Sulphidic Materials

    Directory of Open Access Journals (Sweden)

    Benito Heru Purwanto

    2012-09-01

    Full Text Available Much of peatland in Indonesia has sulphidic materials as substratum. Soil acidity and metal elements in peatland may originate from the sulphidic materials which occur underneath of the peat layer. Peat soil buffering capacity and chelating ability of the peat materials regulate the soil acidity and metal solubility in the peatland. The study was aimed to examine the influence of peat thickness and land hydrological conditions on the concentrations of exchangeable aluminium (Al and hidrogen (H in the peatland. The study was carried out on peaty acid sulphate soil, deep peat, moderate peat and shallow peat. Exchangeable Al and H were observed in the wet season, transition from wet to dry season and dry season. The results showed that exchangeables of Al and H were mainly originated from sulphidic material which were occured underneath of the peat layer. Peat layer had an important role on the solubility of Al and H in the peatland. Peat thickness had influence on exchangeable-Al and H, 50 cm of the peat thickness (shallow peat was the critical for peat function to reduce the Al and H solubility in the peatland. Hydrological condition factor did not influence on the solubility of Al and H.

  2. Frequency characterization of thin soft magnetic material layers used in spiral inductors

    Energy Technology Data Exchange (ETDEWEB)

    Kriga, Adoum; Allassem, Desire [Universite de Lyon, F-42023 Saint Etienne (France); Universite de Saint Etienne, Jean Monnet, F-42023 Saint Etienne (France); LT2C, F-42023 Saint Etienne (France); Soultan, Malloum [Universite de N' Djamena N' Djamena (Chad); Chatelon, Jean-Pierre; Siblini, Ali [Universite de Lyon, F-42023 Saint Etienne (France); Universite de Saint Etienne, Jean Monnet, F-42023 Saint Etienne (France); LT2C, F-42023 Saint Etienne (France); Allard, Bruno [Laboratoire Ampere INSA-Lyon 20, avenue Einstein 69621 Villeurbanne Cedex France (France); Rousseau, Jean Jacques, E-mail: rousseau@univ-st-etienne.fr [Universite de Lyon, F-42023 Saint Etienne (France); Universite de Saint Etienne, Jean Monnet, F-42023 Saint Etienne (France); LT2C, F-42023 Saint Etienne (France)

    2012-07-15

    The paper details the characterization of thin magnetic materials layers, particularly soft materials, with respect to their behaviour in frequency (from 10 MHz to 1 GHz). The proposed method is suitable for any soft but insulating magnetic material; Yttrium Iron Garnet (YIG) is used as an example. The principle is based on a comparison between simulations for different values of the permeability and measurement values versus frequency of planar inductor structures; an experimental validation is proposed as well. Thin magnetic material is first deposited on an alumina substrate using RF sputtering technique; a planar spiral winding of copper is then deposited on the magnetic material by the same technique. The effective permeability versus frequency is obtained by comparing two samples of spiral windings with and without magnetic material. Network analyser measurements on samples of various geometrical dimensions and of different thicknesses are necessary to determine the effective magnetic permeability; we have obtained a relative effective permeability of about 30 for seven turns spiral inductor of a 17 {mu}m YIG film. - Highlights: Black-Right-Pointing-Pointer A simple and original method is presented for the characterization of soft magnetic layer. Black-Right-Pointing-Pointer This is a non-destructive method based on standard equipment. Black-Right-Pointing-Pointer The principle is based on a comparison between simulations and measurement. Black-Right-Pointing-Pointer An experimental validation is proposed as well.

  3. 3D-printed silicate porous bioceramics using a non-sacrificial preceramic polymer binder.

    Science.gov (United States)

    Zocca, A; Elsayed, H; Bernardo, E; Gomes, C M; Lopez-Heredia, M A; Knabe, C; Colombo, P; Gnster, J

    2015-06-01

    Silicate bioceramics possess an excellent bioactivity; however, shaping them into complex geometries is still challenging. Therefore, this paper aims to present a new strategy for the shaping of a bioglass-ceramic with controlled geometry and properties starting from a glass powder combined with a preceramic polymer, i.e. a silicon resin, and reactive fillers. The powder-based three-dimensional (3D)-printing of wollastonite (CaSiO3)-based silicate bioceramic parts was demonstrated in this work. The resin plays a dual role, as it not only acts as a non-sacrificial binder for the filler powders in the printing process but it also reacts with the fillers to generate the desired bioceramic phases. The mechanical and physical properties, i.e. ball-on-three-balls test, density, porosity and morphology, were evaluated in 3D-printed discs. These samples possessed a total porosity around 64 vol% and a biaxial flexural strength around 6 MPa. The raw materials used in this work also enabled the 3D-printing of scaffolds possessing a designed multi-scale porosity, suitable bioceramic phase assemblage and a compressive strength of 1 MPa (for cylindrical scaffolds with total porosity ~80 vol%). Solubility in TRIS/HCl and in vitro assays, i.e. viability, cytotoxicity and apoptosis assays, were also performed. In vitro tests indicated good cell viability and no cytotoxicity effect on the cells. PMID:26000907

  4. Restricted equivalence of paired epsilon-negative and mu-negative layers to a negative phase-velocity material ({\\em alias} left-handed material)

    OpenAIRE

    Lakhtakia, A.; Krowne, C. M.

    2003-01-01

    The time-harmonic electromagnetic responses of (a) a bilayer made of an epsilon-negative layer and a mu-negative layer, and (b) a single layer of a negative phase-velocity material are compared. Provided all layers are electrically thin, a restricted equivalence between (a) and (b) exists. The restricted equivalence depends on the linear polarization state and the transverse wavenumber. Implications for perfect lenses and parallel-plate waveguides are considered.

  5. Characterization of spatially modulated multicomponent materials deposited by atomic layer deposition

    Science.gov (United States)

    Becker, Nicholas

    CHARACTERIZATION OF SPATIALLY MODULATED MULTICOMPONENT MATERIALS DEPOSITED BY ATOMIC LAYER DEPOSITION Nicholas G. Becker, Ph.D. Illinois Institute of Technology, July 2014 Adviser: Dr. John F. Zasadzinski Spatially modulated multicomponent materials are used in a variety of fields and industries. In this dissertation Atomic Layer Deposition (ALD) will be used to create two types of spatially modulated materials: Erbium doped Yttrium Oxide (Er +3:Y2O3) for high-energy lasers and standard reference materials for Synchrotron based X-ray Fluorescence (SXRF) and Scanning Transmission X-ray Microscopy (STXM). Er+3:Y2O 3 was produced and the inter- and intra-layer doping of each film was controlled by the cycle ration of ALD grown Er2O3:Y 2O3 and the steric hinderance of erbium precursor ligands, respectively. Photoluminescent spectroscopy and x-ray diffraction measurements showed that all films of Er+3:Y2O3 were crystalline as deposited, with no evidence of amorphous, or glassy, emission lines in the PLS spectra. Photoluminescent Lifetime (PLL) measurements were performed to prove that ALD can be used to control both the inter- and intra-layer doping. PLL was shown to vary with both Er2O3:Y 2O3 cycle ratio ad with erbium precursor growth rate, increasing to a maximum of 6.5ms. This is the longest PLL reported for ALD grown Er +3:Y 2O3. Results from Rutherford backscattering spectroscopy, x-ray absorption fine structure spectroscopy, and ultraviolet to visible light spectroscopy are presented to verify inter- and intra-layer doping control. Standard reference materials for SXRF and STXM were produced via ALD on transmission electron microscopy windows and native oxide silicon. Materials produced were Fe203, TiO2, ZnO, AlO 3, and Y2O3. Films were analyzed with SXRF, and STXM to determine the optical density and from this the areal density was calculated using preexisting standard reference materials and absorption value charts. It was found that the RBS measurements were more precise, and were within the error associated with the SXRF and STXM measurements.

  6. Crystallographic dependence of the lateral undercut wet etch rate of Al0.5In0.5P in diluted HCl for III-V sacrificial release

    DEFF Research Database (Denmark)

    Ansbk, Thor; Semenova, Elizaveta

    2013-01-01

    The authors investigated the use of InAlP as a sacrificial layer lattice-matched to GaAs when diluted hydrochloric acid is used for sacrificial etching. They show that InAlP can be used to fabricate submicrometer air gaps in micro-opto-electro-mechanical systems and that a selectivity toward GaAs larger than 500 is achieved. This selectivity enables fabrication control of the nanometer-size structures required in photonic crystal and high-index contrast subwavelength grating structures. The crystallographic dependence of the lateral etch rate in InAlP is shown to be symmetric around the ?110? directions where an etch rate of 0.5??m/min is obtained at 22?C in HCl:2H2O. Since the etch rate in the ?100? directions exceeds by ten times that of the ?110? directions, InAlP may be used in sacrificial release of high-aspect ratio structures. Free-hanging structures with length to air-gap aspect ratios above 600 are demonstrated by use of critical point drying following the sacrificial etch.

  7. Electrochemical reactions of layered niobate material as novel anode for sodium ion batteries

    Science.gov (United States)

    Nakayama, Hideki; Nose, Masafumi; Nakanishi, Shinji; Iba, Hideki

    2015-08-01

    The electrochemical performances of layered niobium oxide materials were investigated for the first time as novel anode active materials for the sodium-ion battery. The layered niobate with the formula KNb3O8 was synthesized by a solid-state reaction and has been evaluated as an anode electrode by a cyclic voltammetry technique and galvanostatic charge/discharge tests. The crystal structure of KNb3O8 contains the NbO6 octahedral units and potassium alkali-metal ions interlayer to form the layered structure. KNb3O8 has a redox reaction around 1 V vs. Na/Na+ and has a reversible capacity of 104 mAh/g corresponding to the 1.7 Na+ insertion/extraction in the KNb3O8 structure. The Nb K-edge X-ray absorption near edge structure (XANES) shows that the Nb oxidation state is converted from Nb5+ to Nb4+ during the Na+ insertion stage, and reversibly recovered to Nb5+ during the Na+ extraction stage. This is the first report that the layered niobate of KNb3O8 reversibly reacts with Na+ at the potential around 1 V vs. Na/Na+ via the Nb5+/4+ redox reaction.

  8. DETERMINATION OF MECHANICAL STRENGTH OF SAME MATERIAL DOUBLE-LAYER RECTANGULAR TABLETS

    Directory of Open Access Journals (Sweden)

    ISMAEL HARTRIAN

    2000-07-01

    Full Text Available The mechanical strength of same material composite beams of Avicel PHI02, Starch 1500 and Emcompress were assessed by three-point bending test. To provide an improved method of comparing the strength of the tablets, the tensile strength of the specimens was calculated by equations based on stress analysis. Increasing the compaction pressure led to decrease of the porosity of the compacted tablets while the overall mass of the composite tablets were kept constant. Meanwhile, the values of fracture load and strengths (including tensile and shear raised by increasing the compaction pressure. However, when the lower layer was compacted twice, the value of tensile stress of the lower layer was more than its value in a single compacted tablet with the same material. This observation was attributed to the extent of the reduction of porosity during compaction of the single tablets which raised in their tensile strength values.

  9. New layered metal oxides as positive electrode materials for room-temperature sodium-ion batteries

    Science.gov (United States)

    Mu, Lin-Qin; Hu, Yong-Sheng; Chen, Li-Quan

    2015-03-01

    In order to achieve better Na storage performance, most layered oxide positive electrode materials contain toxic and expensive transition metals Ni and/or Co, which are also widely used for lithium-ion batteries. Here we report a new quaternary layered oxide consisting of Cu, Fe, Mn, and Ti transition metals with O3-type oxygen stacking as a positive electrode for room-temperature sodium-ion batteries. The material can be simply prepared by a high-temperature solid-state reaction route and delivers a reversible capacity of 94 mAh/g with an average storage voltage of 3.2 V. This paves the way for cheaper and non-toxic batteries with high Na storage performance. Project supported by the National Natural Science Foundation of China (Grant Nos. 51222210 and 11234013) and the One Hundred Talent Project of the Chinese Academy of Sciences.

  10. Sound transmission through double cylindrical shells lined with porous material under turbulent boundary layer excitation

    Science.gov (United States)

    Zhou, Jie; Bhaskar, Atul; Zhang, Xin

    2015-11-01

    This paper investigates sound transmission through double-walled cylindrical shell lined with poroelastic material in the core, excited by pressure fluctuations due to the exterior turbulent boundary layer (TBL). Biot's model is used to describe the sound wave propagating in the porous material. Three types of constructions, bonded-bonded, bonded-unbonded and unbonded-unbonded, are considered in this study. The power spectral density (PSD) of the inner shell kinetic energy is predicted for two turbulent boundary layer models, different air gap depths and three types of polyimide foams, respectively. The peaks of the inner shell kinetic energy due to shell resonance, hydrodynamic coincidence and acoustic coincidence are discussed. The results show that if the frequency band over the ring frequency is of interest, an air gap, even if very thin, should exist between the two elastic shells for better sound insulation. And if small density foam has a high flow resistance, a superior sound insulation can still be maintained.

  11. Microstructural characterization of mixed-material deposition layer on the LHD divertor tiles by using nano-geological diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Tokitani, M., E-mail: tokitani.masayuki@LHD.nifs.ac.jp [National Institute for Fusion Science, Oroshi, Toki, Gifu 509-5292 (Japan); Masuzaki, S. [National Institute for Fusion Science, Oroshi, Toki, Gifu 509-5292 (Japan); Yoshida, N. [Research Institute for Applied Mechanics, Kyushu University, Kasuga-Koen, Kasuga, Fukuoka 816-8580 (Japan); Sagara, A.; Noda, N.; Yamada, H. [National Institute for Fusion Science, Oroshi, Toki, Gifu 509-5292 (Japan)

    2013-07-15

    Fusion plasma research crucially needs to understand the characteristics of the deposition layer that forms in the vacuum vessel because of the migration of plasma-facing materials. Such a deposition layer can accumulate on the fuel particles on account of a co-deposition process and can be a source of dust in the plasma. In this study, nano-geological diagnosis which uses a focused ion beam (FIB) fabrication technique and transmission electron microscope (TEM) observations, has been applied to the mixed-material deposition layer formed in a large helical device (LHD). A cross-sectional view of the deposition layer with nanometer resolution was successfully observed. The total thickness of the layer was estimated at ?8 ?m, and it has very fine and stratified layer structures in the nanometer level. The characteristics of each layer are indicative of the operational history of the LHD and the mechanism of dust formation by layer flaking.

  12. Layer-dependent wall properties of abdominal aortic aneurysms: Experimental study and material characterization.

    Science.gov (United States)

    Sassani, Sophia G; Kakisis, John; Tsangaris, Sokrates; Sokolis, Dimitrios P

    2015-09-01

    Mechanical testing and in-depth characterization of the abdominal aortic aneurysm wall from fifteen patients undergoing open surgery was performed to establish the layer-dependent tissue properties that are non-available in the literature. Quantitative microscopic evaluation was performed to identify the spatial organization of collagen-fiber network. Among a number of candidate models, the four-fiber family (microstructure-motivated) model, especially that including dispersions of fiber angles about the main directions, was superior to the Fung- and Gasser-type models in the fitting quality allowed, though it presented a practical difficulty in parameter estimation, so that an analysis was conducted aiding the identification of a more specific diagonal- and circumferential-fiber family model for all three layers. The adventitia was stiffer and stronger than the other layers, owing to its increased collagen content, and its contribution to the response of the intact wall was augmented being under greater residual tension than the media, whereas the intima was under residual compression. All layers were stiffer circumferentially than longitudinally, due to preferential collagen arrangement along that axis. The histologically-guided material characterization of layered wall presented herein is expected to assist clinical decision, by developing reliable criteria to predict the rupture risk of abdominal aortic aneurysms, and optimize endovascular interventions. PMID:26011656

  13. Synthesis and characterisation of gas sensor materials obtained from Pt/Zn/Al layered double hydroxides

    OpenAIRE

    GHIOTTI, Giovanna; MORANDI, Sara; PRINETTO, Federica

    2006-01-01

    We reported about the possibility to employ Zn(Al)O and PtZn(Al)O mixed oxides obtained from layered double hydroxides (LDH) as gas sensor materials. We prepared the samples following two different routes: a classical co-precipitation and a solgel method. After structural and textural characterisation, the powders were studied by FT-IR spectroscopy under different controlled atmospheres at different temperatures. Eventually, conductance measurements were performed on thick films of these...

  14. Polycrystalline SiC as source material for the growth of fluorescent SiC layers

    DEFF Research Database (Denmark)

    Kaiser, M.; Hupfer, T.

    2013-01-01

    Polycrystalline doped SiC act as source for fluorescent SiC. We have studied the growth of individual grains with different polytypes in the source material. We show an evolution and orientation of grains of different polytypes in polycrystalline SiC ingots grown by the Physical Vapor Transport method. The grain influence on the growth rate of fluorescent SiC layers grown by a sublimation epitaxial process is discussed in respect of surface kinetics.

  15. Automatic identification of single- and/or few-layer thin-film material

    DEFF Research Database (Denmark)

    One or more digital representations of single- (101) and/or few-layer (102) thin- film material are automatically identified robustly and reliably in a digital image (100), the digital image (100) having a predetermined number of colour components, by - determining (304) a background colour...... component of the digital image (100) for each colour component, and - determining or estimating (306) a colour component of thin-film material to be identified in the digital image (100) for each colour component by obtaining a pre-determined contrast value (C R; C G; C B) for each colour component and...

  16. Fatigue crack growth and fracture mechanics analysis of a working roll surface layer material

    Directory of Open Access Journals (Sweden)

    M. Drobne

    2014-10-01

    Full Text Available Fatigue crack growth and fracture mechanics analysis of a working roll surface layer material is presented in this paper. The research is done on a hot strip mill working roll where High Chromium Steel is used for rolls shell material. To obtain corresponding parameters, a rectangular single edge notched bend specimens SENB, according to standard BS 7448, were used. The fatigue crack growth analysis was done on a resonant testing machine with use of special crack gauges, while for fracture mechanics parameters the electromechanical testing machine was used.

  17. Casimir Piston of Real Materials and its Application to Multi-Layer Models

    OpenAIRE

    L.P. Teo

    2009-01-01

    In this article, we derive the formula for the Casimir force acting on a piston made of real material moving inside a perfectly conducting rectangular box. It is shown that by taking suitable limits, one recovers the formula for the Casimir force acting on a perfectly conducting piston or an infinitely permeable piston. Lifshitz formula for finite temperature Casimir force acting on parallel plates made of real materials is re-derived by considering the five-layer model in the context of pist...

  18. Development of N-layer materials for SNS junction and SQUID applications

    International Nuclear Information System (INIS)

    Materials characteristics including water reactivity, oxygen loss, electromigration of oxide ions, and interfacial reactivity problems have plagued attempts to produce reliable and reproducible cuprate SNS superconductor junctions. In an effort to solve some of these formidable problems, new N-layer compounds from the family of R1-xCaxBa2-yLayCu3-zMzO7-? (R = Y, Gd and Pr; M = Co, Ni and Zn; 0 2Cu3O7-? phase and the modified materials exhibit enhanced durability properties. The compounds have been utilized to make both SNS junctions and SQUID devices

  19. Examination of a phase change material's layer efficiency when applied in a building's envelope

    Science.gov (United States)

    Briola, Maria

    2015-02-01

    This paper consists of both a theoretical and an experimental study of phase change materials. Specifically, the theoretical part starts with a reference to the need of using new energy-saving technologies with phase change materials and an introduction to thermal energy storage. Then, follows the presentation of the properties of these materials and the methods of their measurement, their classification in categories as well as the methods of simulating PCM. After that, the paper analyzes the most common PCM applications in buildings. The experimental part examines the efficiency of a phase change material (PCM) layer, embedded in a south, east, west and north-oriented wall which is charged externally by the sun, in relation to various parameters. Summing up, this paper brings together the results and final conclusions drawn by the experimental study, presenting several recommendations for future work.

  20. New Material Development for Surface Layer and Surface Technology in Tribology Science to Improve Energy Efficiency

    Science.gov (United States)

    Ismail, R.; Tauviqirrahman, M.; Jamari, Jamari; Schipper, D. J.

    2009-09-01

    This paper reviews the development of new material and surface technology in tribology and its contribution to energy efficiency. Two examples of the economic benefits, resulted from the optimum tribology in the transportation sector and the manufacturing industry are discussed. The new materials are proposed to modify the surface property by laminating the bulk material with thin layer/coating. Under a suitable condition, the thin layer on a surface can provide a combination of good wear, a low friction and corrosion resistance for the mechanical components. The innovation in layer technology results molybdenum disulfide (MoS2), diamond like carbon (DLC), cubic boron nitride (CBN) and diamond which perform satisfactory outcome. The application of the metallic coatings to carbon fibre reinforced polymer matrix composites (CFRP) has the capacity to provide considerable weight and power savings for many engineering components. The green material for lubricant and additives such as the use of sunflower oil which possesses good oxidation resistance and the use of mallee leaves as bio-degradable solvent are used to answer the demand of the environmentally friendly material with good performance. The tribology research implementation for energy efficiency also touches the simple things around us such as: erasing the laser-print in a paper with different abrasion techniques. For the technology in the engineering surface, the consideration for generating the suitable surface of the components in running-in period has been discussed in order to prolong the components life and reduce the machine downtime. The conclusion, tribology can result in reducing manufacturing time, reducing the maintenance requirements, prolonging the service interval, improving durability, reliability and mechanical components life, and reducing harmful exhaust emission and waste. All of these advantages will increase the energy efficiency and the economic benefits.

  1. Biomacromolecule immobilization and self-assembled monolayer chemistry on atomic layer deposited metal oxide materials

    Science.gov (United States)

    Bergkvist, Magnus

    2009-10-01

    Many biotechnology applications involve interfacing proteins, DNA and other macromolecules to non-biological material surfaces acting as supports. Support materials employed for this purpose span the periodic table and range from polymeric membranes/hydrogels to metals and ceramics, for example gold and hydroxyapatite. Lab-on-a-chip and other sensing/detection applications based on lithography and semiconductor technology typically rely on alkanethiol and organosilane chemistry to immobilize biological material to gold and silica. While successful in many instances, organosilane chemistry offers limited options for orthogonal chemistry and often results in multilayer film buildup. Self-assembly on gold is straight forward but gold is often undesirable from a device perspective. Recent developments in atomic layer deposition (ALD) allow fabrication of high quality thin films of alumina and high-k oxide materials that are compatible with clean room operations and are interesting emerging materials for integrated optical, electronic and biological applications. Here we will show alternative self-assembly chemistries on ALD materials for biological immobilization than those used on gold/silica and also demonstrate direct biological interfacing to high-K materials for potential use in bioscreening and detection.

  2. he sacrificial emplotment of national identity. Pdraic Pearse and the 1916 Easter uprising

    Directory of Open Access Journals (Sweden)

    Patrick Colm Hogan

    2014-06-01

    Full Text Available A sense of national identification remains amorphous and inert unless it is cognitively structured and motivationally oriented. Perhaps the most consequential way of structuring and orienting nationalism is through emplotment (organizing in the form of a story. Emplotment commonly follows one of a few cross-culturally recurring genres. In nationalist contexts, the heroic genretreating military conflict, loss or potential loss, and reasserted sovereigntyis the default form. However, this default may be overridden in particular circumstances. When social devastation precludes heroic achievement, a sacrificial emplotmenttreating collective sin, punishment, sacrifice, and redemptionis often particularly salient. Earlier work has examined cases of sacrificial emplotment in its most extreme varieties (treating Hitler and Gandhi. The following essay considers a more ordinary case, the sacrificial nationalism of the prominent Irish anti-colonial revolutionary, Pdraic Pearse, as represented in his plays.

  3. Suitability of Structural Aluminium Profiles as Sacrificial Anode for Carbon Steel

    Directory of Open Access Journals (Sweden)

    Iyiola O. OTUNNIYI

    2012-11-01

    Full Text Available The life of low carbon steels in many small scale structures can be remarkably prolonged by complementary sacrificial anode cathodic protection (SACP but for constraints in availability of specialty anodes. Suitability of commonly available structural aluminium profiles as sacrificial anodes for low carbon steel has been investigated. Three different profiles were studied. Bare and coated steel samples were found to migrate clearly too cathodic potential regimes when coupled with the press-finish BS1470:6000 AlMgSi series alloy in a chloride medium. No weight loss was observed for the coated steel sample, while the aluminium profile showed dissolution. This alloy, commonly available in press-finish profiles for structural purposes, is therefore recommendable as sacrificial anodes for complementary SACP of low carbon steel structures under atmospheric or aqueous exposures.

  4. Preparation of a hologram composed of a striped gold layer using photographic materials

    Science.gov (United States)

    Kuge, Ken'ichi; Nakao, Tomoaki; Goto, Yoshimasa; Omatsu, Takashige; Hasegawa, Akira

    2006-07-01

    We prepare a diffraction grating composed of the gold layer on a glass plate using the gold deposition development in photographic materials and following baking process. A high-resolution image with a spatial resolution of over 4000lines/mm was obtained. A diffraction grating composed of gold particles in a gelatin layer was prepared by development in a gold-thiocyanate complex solution. The grating was then baked to burn out the gelatin layer and fuse the gold particles. The thickness of the grating composed of the gold layer was less than 10nm. After baking the grating had a bright gold luster and showed a clear higher-order diffraction on the reflecting side, while it showed only first-order diffraction before baking. The maximum efficiency of the first-order diffraction beam on the grating before baking was 8.8%. After baking, the maximum efficiency of the reflected diffraction beam was 1.6%. Using this method, it is possible to prepare stable holograms even in severe environments.

  5. A proposed method to determine the adherence for the layers made out of thermal sprayed materials on internal cylindrical surfaces

    Directory of Open Access Journals (Sweden)

    Adrian V. Petrica

    2005-10-01

    Full Text Available The paper presents an investigation method for the adherence of the layers made out of thermal sprayed materials on the inner surface of some parts. The base material is made of steel. The deposition procedure was the electric arc thermal spraying, flame spraying asnd plasma spraying and the filler materials used were: copper, brass and aluminum bronze. The proposed method analyses the adherence force by measuring the shear unit fracture stress of the deposited layers.

  6. Vertically stacked multi-heterostructures of layered materials for logic transistors and complementary inverters

    Science.gov (United States)

    Yu, Woo Jong; Li, Zheng; Zhou, Hailong; Chen, Yu; Wang, Yang; Huang, Yu; Duan, Xiangfeng

    2013-03-01

    Graphene has attracted considerable interest for future electronics, but the absence of a bandgap limits its direct applicability in transistors and logic devices. Recently, other layered materials such as molybdenum disulphide (MoS2) have been investigated to address this challenge. Here, we report the vertical integration of multi-heterostructures of layered materials for the fabrication of a new generation of vertical field-effect transistors (VFETs) with a room temperature on-off ratio > 103 and a high current density of up to 5,000?A?cm-2. An n-channel VFET is created by sandwiching few-layer MoS2 as the semiconducting channel between a monolayer graphene sheet and a metal thin film. This approach offers a general strategy for the vertical integration of p- and n-channel transistors for high-performance logic applications. As an example, we demonstrate a complementary inverter with a larger-than-unity voltage gain by vertically stacking graphene, Bi2Sr2Co2O8 (p-channel), graphene, MoS2 (n-channel) and a metal thin film in sequence. The ability to simultaneously achieve a high on-off ratio, a high current density and a logic function in such vertically stacked multi-heterostructures can open up possibilities for three-dimensional integration in future electronics.

  7. Strain–displacement relations for strain engineering in single-layer 2d materials

    Science.gov (United States)

    Midtvedt, Daniel; Lewenkopf, Caio H.; Croy, Alexander

    2016-03-01

    We investigate the electromechanical coupling in single-layer 2d materials. For non-Bravais lattices, we find important corrections to the standard macroscopic strain-microscopic atomic-displacement theory. We put forward a general and systematic approach to calculate strain–displacement relations for several classes of 2d materials. We apply our findings to graphene as a study case, by combining a tight binding and a valence force-field model to calculate electronic and mechanical properties of graphene nanoribbons under strain. The results show good agreement with the predictions of the Dirac equation coupled to continuum mechanics. For this long wave-limit effective theory, we find that the strain–displacement relations lead to a renormalization correction to the strain-induced pseudo-magnetic fields. A similar renormalization is found for the strain-induced band-gap of black phosphorous. Implications for nanomechanical properties and electromechanical coupling in 2d materials are discussed.

  8. Layered oxychalcogenide in the BiCuOSe system as good thermoelectric materials

    International Nuclear Information System (INIS)

    Since 2010, we have evidenced the very promising thermoelectric properties of layered oxychalcogenides, with parent compound BiCuSeO, which could be used in thermoelectric conversion systems in the 300600C temperature range. These materials, that were first studied in the early 2000s for their optoelectronic properties, exhibit thermoelectric figure of merit values around 1.4 at 650C, which makes them the best lead- or tellurium-free p-type thermoelectric materials ever reported to date. In this paper, we will review the chemical, structural and physical properties of this family of materials, with an emphasis on the links between crystal structure, electronic structure and functional properties. (paper)

  9. Friction of sheared granular layers: Role of particle dimensionality, surface roughness, and material properties

    Science.gov (United States)

    Knuth, Matthew; Marone, Chris

    2007-03-01

    We report on laboratory experiments designed to investigate three fundamental deformation mechanisms for frictional shear of granular fault gouge: sliding, rolling, and dilation. Mechanisms were isolated by shearing layers composed of rods in geometric configurations that resulted in one-dimensional, two-dimensional, and rolling-only particle interactions. Results of digital video are presented with measurements of friction and strain to illuminate the distribution of shear and the relationship between particle motions and friction. The double-direct-shear configuration was used with boundary conditions of constant layer normal stress (1 MPa) and controlled shear loading rate (10 ?m/s) with initial layer thickness of 6 mm. Layers were sheared in a servo-hydraulic testing machine at room temperature (22C) and relative humidity (5 to 10%). Three materials were studied: alloy 260 brass, dried semolina pasta, and hardwood dowels, with particle diameters of 1.59 mm, 1.86 mm, and 2.06 mm, respectively. Pasta layers had mean sliding friction coefficients of 0.24, 0.11, and 0.02 in 2-D, 1-D, and rolling configurations, respectively. Layers of brass rods had average friction coefficients of 0.23, 0.15, and 0.01, respectively, in 2-D, 1-D, and rolling configurations; and the wood samples exhibited friction values of 0.18, 0.19, and 0.09, respectively. Evolution of strength during shear correlated strongly with the displacement derivative of layer thickness. SEM images document the role of surface finish on frictional properties. Rapid reorientations of particles correspond to stick-slip stress drops and may be related to the collapse and reformation of granular force chains. We find a systematic relationship between the strength of granular layers and (1) the surface roughness of particles and (2) the number of particle contact dimensions. Our data provide important insights on the mechanics of granular fault gouge and constraints on the fundamental parameters used in numerical models of tectonic faulting.

  10. Polymer magnetic microactuators fabricated with hot embossing and layer-by-layer nano self-assembly.

    Science.gov (United States)

    Xue, Wei; Cui, Tianhong

    2007-08-01

    Polymer-based magnetic microactuators have been fabricated with hot embossing technique and layer-by-layer (LbL) nano self-assembly. Silicon molds are fabricated with conventional UV lithography and wet etching techniques. Hot embossing is used to transfer the patterns from silicon molds to polymethylmethacrylate (PMMA) sheets. The overall processing time for the pattern transfer is less than 20 min. Low-cost devices with massive and rapid replication can be fabricated. Six layers of magnetic iron oxide (Fe2O3) nanoparticles are LbL self-assembled on the PMMA surface as the magnetically sensitive material. Positive photoresist PR1813 is used as the sacrificial layer to protect the gold electrode on the back side of the membrane. LbL nano self-assembly technique provides a simple method to obtain the magnetic film with low cost, short processing time, simple fabrication steps at room temperature. The volume of the magnetic material can be precisely controlled by the number of nano-assembled iron oxide layers. The mechanical, electrical, and magnetic properties of the microactuator are characterized by a laser interferometer. The natural frequency of the actuator is approximately 151 Hz; and the maximum deflection amplitude is about 34 nm. At all frequencies, the increase of the magnetic field increases the deflection amplitude which is in agreement with the theoretical equation. PMID:17685279

  11. Microscopic observation of pattern attack by aggressive ions on finished surface of aluminium alloy sacrificial anode

    International Nuclear Information System (INIS)

    This paper presents the results of a microscopic observation on submerged finished surface of aluminium alloy sacrificial anode. Experimental tests were carried out on polished surface aluminium anode exposed to seawater containing aggressive ions in order to observe of pattern corrosion attack on corroding surface of anode. Results have shown, at least under the present testing condition, that surface of sacrificial anode were attack by an aggressive ion such as chloride along grain boundaries. In addition, results of microanalysis showed that the corrosion products on surface of aluminium alloy have Al, Zn and O element for all sample and within the pit was consists of Al, Zn, O and Cl element. (author)

  12. Monolithic multilayer microfluidics via sacrificial molding of 3D-printed isomalt

    OpenAIRE

    Gelber, Matthew K.; Bhargava, Rohit

    2015-01-01

    Here we demonstrate a method for creating multilayer or 3D microfluidics by casting a curable resin around a water-soluble, freestanding sacrificial mold. We use a purpose-built 3D printer to pattern self-supporting filaments of the sugar alcohol isomalt, which we then back-fill with a transparent epoxy resin. Dissolving the sacrificial mold leaves a network of cylindrical channels as well as input and output ports. We use this technique to fabricate a combinatorial mixer capable of producing...

  13. Tuning the Transport Properties of Layered Materials for Thermoelectric Applications using First-Principles Calculations

    KAUST Repository

    Saeed, Yasir

    2014-05-11

    Thermoelectric materials can convert waste heat into electric power and thus provide a way to reduce the dependence on fossil fuels. Our aim is to model the underlying materials properties and, in particular, the transport as controlled by electrons and lattice vibrations. The goal is to develop an understanding of the thermoelectric properties of selected materials at a fundamental level. The structural, electronic, optical, and phononic properties are studied in order to tune the transport, focusing on KxRhO2, NaxRhO2, PtSb2 and Bi2Se3. The investigations are based on density functional theory as implemented in the all electron linearized augmented plane wave plus local orbitals WIEN2k and pseudo potential Quantum-ESPRESSO codes. The thermoelectric properties are derived from Boltzmann transport theory under the constant relaxation time approximation, using the BoltzTraP code. We will discuss first the changes in the electronic band structure under variation of the cation concentration in layered KxRhO2 in the 2H phase and NaxRhO2 in the 3R phase. We will also study the hydrated phase. The deformations of the RhO6 octahedra turn out to govern the thermoelectric properties, where the high Seebeck coefficient results from ”pudding mold" bands. We investigate the thermoelectric properties of electron and hole doped PtSb2, which is not a layered material but shares “pudding mold" bands. PtSb2 has a high Seebeck coefficient at room temperature, which increases significantly under As alloying by bandgap opening and reduction of the lattice thermal conductivity. Bi2Se3 (bulk and thin film) has a larger bandgap then the well-known thermoelectric material Bi2Te3, which is important at high temperature. The structural stability, electronic structure, and transport properties of one to six quintuple layers of Bi2Se3 will be discussed. We also address the effect of strain on a single quintuple layer by phonon band structures. We will analyze the electronic and transport properties of Tl-doped Bi2Se3 under strain, focusing on the giant Rashba spin splitting (Tl doping breaks the inversion symmetry in Bi2Se3) and its dependence on biaxial tensile and compressive strain.

  14. Few layer epitaxial germanene: a novel two-dimensional Dirac material

    Science.gov (United States)

    Dávila, María Eugenia; Le Lay, Guy

    2016-02-01

    Monolayer germanene, a novel graphene-like germanium allotrope akin to silicene has been recently grown on metallic substrates. Lying directly on the metal surfaces the reconstructed atom-thin sheets are prone to lose the massless Dirac fermion character and unique associated physical properties of free standing germanene. Here, we show that few layer germanene, which we create by dry epitaxy on a gold template, possesses Dirac cones thanks to a reduced interaction. This finding established on synchrotron-radiation-based photoemission, scanning tunneling microscopy imaging and surface electron diffraction places few layer germanene among the rare two-dimensional Dirac materials. Since germanium is currently used in the mainstream Si-based electronics, perspectives of using germanene for scaling down beyond the 5 nm node appear very promising. Other fascinating properties seem at hand, typically the robust quantum spin Hall effect for applications in spintronics and the engineering of Floquet Majorana fermions by light for quantum computing.

  15. Li-rich layer-structured cathode materials for high energy Li-ion batteries

    Science.gov (United States)

    Li, Liu; Lee, Kim Seng; Lu, Li

    2014-08-01

    Li-rich layer-structured xLi2MnO3 ? (1 - x)LiMO2 (M = Mn, Ni, Co, etc.) materials have attracted much attention due to their extraordinarily high reversible capacity as the cathode material in Li-ion batteries. To better understand the nature of this type of materials, this paper reviews history of development of the Li-rich cathode materials, and provides in-depth study on complicated crystal structures and reaction mechanisms during electrochemical charge/discharge cycling. Despite the fabulous capability at low rate, several drawbacks still gap this type of high-capacity cathode materials from practical applications, for instance the large irreversible capacity loss at first cycle, poor rate capability, severe voltage decay and capacity fade during electrochemical charge/discharge cycling. This review will also address mechanisms for these inferior properties and propose various possible solutions to solve above issues for future utilization of these cathode materials in commercial Li-ion batteries.

  16. Understanding the Anchoring Effect of Two-Dimensional Layered Materials for Lithium-Sulfur Batteries.

    Science.gov (United States)

    Zhang, Qianfan; Wang, Yapeng; Seh, Zhi Wei; Fu, Zhongheng; Zhang, Ruifeng; Cui, Yi

    2015-06-10

    Although the rechargeable lithium-sulfur battery system has attracted significant attention due to its high theoretical specific energy, its implementation has been impeded by multiple challenges, especially the dissolution of intermediate lithium polysulfide (Li2Sn) species into the electrolyte. Introducing anchoring materials, which can induce strong binding interaction with Li2Sn species, has been demonstrated as an effective way to overcome this problem and achieve long-term cycling stability and high-rate performance. The interaction between Li2Sn species and anchoring materials should be studied at the atomic level in order to understand the mechanism behind the anchoring effect and to identify ideal anchoring materials to further improve the performance of Li-S batteries. Using first-principles approach with van der Waals interaction included, we systematically investigate the adsorption of Li2Sn species on various two-dimensional layered materials (oxides, sulfides, and chlorides) and study the detailed interaction and electronic structure, including binding strength, configuration distortion, and charge transfer. We gain insight into how van der Waals interaction and chemical binding contribute to the adsorption of Li2Sn species for anchoring materials with strong, medium, and weak interactions. We understand why the anchoring materials can avoid the detachment of Li2S as in carbon substrate, and we discover that too strong binding strength can cause decomposition of Li2Sn species. PMID:25961805

  17. Suitability of polystyrene as a functional barrier layer in coloured food contact materials.

    Science.gov (United States)

    Genualdi, Susan; Addo Ntim, Susana; Begley, Timothy

    2015-01-01

    Functional barriers in food contact materials (FCMs) are used to prevent or reduce migration from inner layers in multilayer structures to food. The effectiveness of functional barrier layers was investigated in coloured polystyrene (PS) bowls due to their intended condition of use with hot liquids such as soups or stew. Migration experiments were performed over a 10-day period using USFDA-recommended food simulants (10% ethanol, 50% ethanol, corn oil and Miglyol) along with several other food oils. At the end of the 10 days, solvent dyes had migrated from the PS bowls at 12, 1 and 31,000 ng cm(-)(2) into coconut oil, palm kernel oil and Miglyol respectively, and in coconut oil and Miglyol the colour change was visible to the human eye. Scanning electron microscope (SEM) images revealed that the functional barrier was no longer intact for the bowls exposed to coconut oil, palm kernel oil, Miglyol, 10% ethanol, 50% ethanol and goat's milk. Additional tests showed that 1-dodecanol, a lauryl alcohol derived from palm kernel oil and coconut oil, was present in the PS bowls at an average concentration of 11 mg kg(-1). This compound is likely to have been used as a dispersing agent for the solvent dye and aided the migration of the solvent dye from the PS bowl into the food simulant. The solvent dye was not found in the 10% ethanol, 50% ethanol and goat's milk food simulants above their respective limits of detection, which is likely to be due to its insolubility in aqueous solutions. A disrupted barrier layer is of concern because if there are unregulated materials in the inner layers of the laminate, they may migrate to food, and therefore be considered unapproved food additives resulting in the food being deemed adulterated under the Federal Food Drug and Cosmetic Act. PMID:25569333

  18. Heat transfer from an internally heated liquid layer

    International Nuclear Information System (INIS)

    This paper is concerned with the development of methods for analyzing the postaccident heat removal characteristics of a fast breeder reactor, specifically, the problem of predicting melting rates of a structural material heated from above by a horizontal layer of molten fuel. There are two important phases of postaccident behavior to which this work particularly applies: penetration of the reactor vessel by molten fuel, and penetration of sacrificial protective barriers. The paper describes the results of analyses of the available experimental correlations of heat transfer in horizontal fluid layers with uniform internal heat sources and develops means to apply the information to analyses of postaccident heat removal in fast reactors. Data and correlations are presented which relate upward and downward heat fluxes from an internally heated liquid layer to the heat generation rate in and thickness of the heated layer and the thermophysical properties of the heated layer. The paper also describes the results of experiments undertaken to assess the feasibility of using microwave heating of liquids to simulate decay heating by fission products in molten fuel. Experimental data are reported on the melting attack on simulant structural materials including paraffin wax and naphthalene by simulant fuel layers, glycerine and ethylene glycol, internally heated by microwave energy. Results are explained in terms of the newly developed correlations for layer heat transfer. Examples of the application to prediction of melting rates of steel structures by mixed-oxide fuel, internally heated by radioactive decay, are described

  19. Atomic-scale friction modulated by potential corrugation in multi-layered graphene materials

    Energy Technology Data Exchange (ETDEWEB)

    Zhuang, Chunqiang, E-mail: chunqiang.zhuang@bjut.edu.cn [Beijing Key Laboratory of Microstructure and Properties of Advanced Materials, Beijing University of Technology, Beijing 100124 (China); Liu, Lei [Institute of Earthquake Science, China Earthquake Administration, Beijing 10036 (China)

    2015-03-21

    Friction is an important issue that has to be carefully treated for the fabrication of graphene-based nano-scale devices. So far, the friction mechanism of graphene materials on the atomic scale has not yet been clearly presented. Here, first-principles calculations were employed to unveil the friction behaviors and their atomic-scale mechanism. We found that potential corrugations on sliding surfaces dominate the friction force and the friction anisotropy of graphene materials. Higher friction forces correspond to larger corrugations of potential energy, which are tuned by the number of graphene layers. The friction anisotropy is determined by the regular distributions of potential energy. The sliding along a fold-line path (hollow-atop-hollow) has a relatively small potential energy barrier. Thus, the linear sliding observed in macroscopic friction experiments may probably be attributed to the fold-line sliding mode on the atomic scale. These findings can also be extended to other layer-structure materials, such as molybdenum disulfide (MoS{sub 2}) and graphene-like BN sheets.

  20. Finite Element Analysis of Layered Fiber Composite Structures Accounting for the Material's Microstructure and Delamination

    Science.gov (United States)

    Stier, Bertram; Simon, Jaan-Willem; Reese, Stefanie

    2015-04-01

    The present paper focuses on composite structures which consist of several layers of carbon fiber reinforced plastics (CFRP). For such layered composite structures, delamination constitutes one of the major failure modes. Predicting its initiation is essential for the design of these composites. Evaluating stress-strength relation based onset criteria requires an accurate representation of the through-the-thickness stress distribution, which can be particularly delicate in the case of shell-like structures. Thus, in this paper, a solid-shell finite element formulation is utilized which allows to incorporate a fully three-dimensional material model while still being suitable for applications involving thin structures. Moreover, locking phenomena are cured by using both the EAS and the ANS concept, and numerical efficiency is ensured through reduced integration. The proposed anisotropic material model accounts for the material's micro-structure by using the concept of structural tensors. It is validated by comparison to experimental data as well as by application to numerical examples.

  1. Visibility of atomically-thin layered materials buried in silicon dioxide

    Science.gov (United States)

    Simsek, Ergun; Mukherjee, Bablu

    2015-11-01

    Recently, the coating of thin oxide or nitride film on top of crystals of atomically-thin layered material (ATLM) has been introduced, which benefits optical and electrical properties of the materials and shields them from environmental contact, and has important implications for optoelectronics applications of layered materials. By calculating the reflection contrast, we show the possibility of using an additional oxide film on top of ATLM with good average optical color contrast in broad- and narrow-band wavelength ranges. Our work presents a more comprehensive map of optical color contrast of various ATLMs including graphene, MoS2, MoSe2, WS2, and WSe2 when kept in a sandwich structure between two thin SiO2 films on a Si substrate. The average color contrasts of ATLMs with varying thicknesses of SiO2 films at three different wavelength ranges (i.e. broadband range, range for green filtering and range for red filtering) have been discussed with a summary of optimized thicknesses of the top and bottom oxide films in order to achieve the highest color contrast from the sandwich structures.

  2. Surface loading on and internal defects in layered magneto-electro-elastic materials and structures

    Science.gov (United States)

    Sangghaleh, Ali

    Magneto-electro-elastic (MEE) materials belong to the category of multi-phase materials where different phases within the materials including elastic, electric, and magnetic ones can interact for the optimal response. These materials are usually composites made of multi-phases or laminae and exhibit magnetoelectric (ME) coupling effect that is not present in the single-phase piezoelectric or piezomagnetic material. Piezoelectric materials display coupling effect between mechanical and electric fields and magnetostrictive materials display coupling effect between mechanical and magnetic fields. Material with an ME effect can exhibit an electric polarization under a magnetic field or a magnetization under an electric field. Natural ME effect is rare and the applications are limited due to the relatively small ME effect and response at low temperature. A few single-phase materials exhibit a weak ME effect. In contrast, a composite with piezoelectric and piezomagnetic phases can demonstrate a strong ME effect. The research on MEE materials started from 1970s and the development of MEEs picked up the pace since the production of high-quality single crystals as well as the improvement of techniques of thin film growth. Computational analyses have also helped to understand the coupling among elastic, electric, and magnetic orderings. In this study, new theoretical method is developed to understand the characteristics of anisotropic MEE materials under circular surface loadings. Numerical results demonstrate interesting features associated with different surface loads and could serve as benchmarks for future numerical methods where indentation research is involved. In addition, the analytical method is extended to analyze the fields produced by three-dimensional (3D) charged dislocations in MEE and piezoelectric (PE) bimaterials in which the materials are taken to be homogeneous and of general anisotropy. The solution is expressed in terms of simple line integrals along the dislocation loop with the integrand being the corresponding point-force Green's functions. The solution contains the piezoelectric, piezomagnetic, and purely elastic responses as special cases. The presented analytical solution and the obtained numerical results will provide a brilliant prospect to understand mechanical and physical behaviors of layered materials/structures and to improve the design and fabrication of novel semiconductors and photovoltaic devices.

  3. Design and Optimization of Passive UHF RFID Tag Antenna for Mounting on or inside Material Layers

    Science.gov (United States)

    Shao, Shuai

    There is great desire to employ passive UHF RFID tags for inventory tracking and sensing in a diversity of applications and environments. Owing to its battery-free operation, non-line-of sight detection, low cost, long read range and small form factor, each year billions of RFID tags are being deployed in retail, logistics, manufacturing, biomedical inventories, among many other applications. However, the performance of these RFID systems has not met expectations. This is because a tag's performance deteriorates significantly when mounted on or inside arbitrary materials. The tag antenna is optimized only for a given type of material at a certain location of placement, and detuning takes place when attached to or embedded in materials with dielectric properties outside the design range. Thereby, different customized tags may be needed for identifying objects even within the same class of products. This increases the overall cost of the system. Furthermore, conventional copper foil-based RFID tag antennas are prone to metal fatigue and wear, and cannot survive hostile environments where antennas could be deformed by external forces and failures occur. Therefore, it is essential to understand the interaction between the antenna and the material in the vicinity of the tag, and design general purpose RFID tag antennas possessing excellent electrical performance as well as robust mechanical structure. A particularly challenging application addressed here is designing passive RFID tag antennas for automotive tires. Tires are composed of multiple layers of rubber with different dielectric properties and thicknesses. Furthermore, metallic plies are embedded in the sidewalls and steel belts lie beneath the tread to enforce mechanical integrity. To complicate matters even more, a typical tire experiences a 10% stretching during the construction process. This dissertation focuses on intuitively understanding the interaction between the antenna and the material in the proximity and designing broad band and mechanically robust RFID tag antennas for elastic materials. As a first step, the effects of dielectric materials on an antenna's impedance match and radiation pattern are investigated. The detuning effect is quantified based on the theoretical frequency scaling and effective permittivity of a dielectric material of finite thickness. Using simple formulas, the operational range of a tag can be predicted without intensive full-wave simulations of different materials. Next, a spectral domain Green's function is applied to compute the antenna pattern when the tag is mounted on or inside a layered medium. The optimal placement of the tag is found based on the focusing effect that the material has on the gain pattern of the antenna. For tires, the steel ply in the sidewall of a tire looks like a periodic wire grating. The performance of an antenna placed close to a wire grating is predicted using Floquet theory. The results indicate that steel plies embedded in the tire can be utilized as a reflector to further focus the gain pattern and increase the read range of a tag. Using these design tools and theoretical analysis, several broadband RFID tag antennas are designed for multi-layered materials. A novel stretchable conductive textile (E-fiber) based tag antenna is also developed for placement in elastic materials. Prototype antennas are fabricated and embedded in a tire during the tire manufacturing process. Experimental results indicate that tags with the new antennas achieve significant improvement compared with commercially available tags.

  4. Crystal Chemical Concept of Arrangement and Function of Layered Superconducting Materials

    OpenAIRE

    Volkova, L. M.; Polyshchuk, S. A.; Magarill, S. A.; Herbeck, F. E.

    2002-01-01

    The crystal chemical concept of arrangement and function of layered superconducting materials is supposed. The concept is based on results of our investigation of crystal chemistry of high-temperature superconductors (HTSC) cuprates, diborides AB2 and borocarbides of nickel RNi2B2C. According to these results: (1) the main role in appearance of superconductivity played by the structural fragments - sandwiches A2(CuO2) in HTSC cuprates, A2(B2) in diborides and RB(Ni) in nicke...

  5. Understanding the Origin of Enhanced Performances in Core-Shell and Concentration-Gradient Layered Oxide Cathode Materials.

    Science.gov (United States)

    Song, Dawei; Hou, Peiyu; Wang, Xiaoqing; Shi, Xixi; Zhang, Lianqi

    2015-06-17

    Core-shell and concentration-gradient layered oxide cathode materials deliver superior electrochemical properties such as long cycle life and outstanding thermal stability. However, the origin of enhanced performance is not clear and seldom investigated until now. Here, a specific structured layered oxide (LiNi0.5Co0.2Mn0.3O2) consisting of concentration-gradient core, transition layer, and stable outer shell, is designed and achieved from double-shelled precursors to overcome the great challenge by comparison with the normal layered LiNi0.5Co0.2Mn0.3O2. As expected, the specific structured layered oxide displays excellent cycle life and thermal stability. After numerous cycles, the valence state of Ni and Co at normal layered oxide surface tends to a higher oxidation state than that of the specific structured oxide, and the spinel phase is observed on particle surface of normal layered oxide. Also, the deficient spinel/layered mixed phases lead to high surface film and charge-transfer resistance for normal layered oxide, whereas the specific structured one still remains a layered structure. Those results first illustrate the origin of improved electrochemical performance of layered core-shell and concentration-gradient cathode materials for lithium-ion batteries. PMID:26017733

  6. Optical properties of PbS-doped silica optical fiber materials based on atomic layer deposition

    International Nuclear Information System (INIS)

    Highlights: PbS-doped silica optical fiber materials have been fabricated by ALD technique. PbS-doped silica optical fiber materials are characterized through XPS, Raman and optical properties. The local structure model of PbS-3MR for the PbS-doped optical fiber materials is built, and its optical properties are investigated using DFT. The computed results of absorption and emission peaks are at 325.7 and 769.8 nm, which are good agreement with our experiment results. - Abstract: Optical properties of PbS-doped silica optical fiber materials and theoretical simulation are investigated. PbS is deposited on silica optical fiber materials by Atomic Layer Deposition (ALD) technique with Pb(tmhd)2 and H2S as Pb and S precursors, respectively. Its stoichiometry is confirmed by X-ray photoelectron spectroscopy (XPS). The valence states of S and Pb element are ?2 and +2, respectively. The Raman spectra further reveal that PbS has been doped into optical fiber materials almost without destroying irregular rings structure in silica material network. And there are distinct absorption bands at 248 and 352 nm. Fluorescence spectra are obtained with 330 and 350 nm pumping, two fluorescence peaks at 768 and 808 nm, respectively. In addition, the microstructure models for PbS-doped optical fiber materials are built on Gaussian09 platform, and its optical properties of the absorption and emission spectra are calculated using density functional theory (DFT) and time-dependent density functional theory (TDDFT) methods. There are obvious absorption and emission peaks at 325.7 and 769.8 nm, respectively, which are in good agreement with experiments

  7. Optical properties of PbS-doped silica optical fiber materials based on atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Yanhua; Wen, Jianxiang; Pang, Fufei; Chen, Zhenyi; Wang, Jie; Luo, Yanhua [Key Laboratory of Specialty Fiber Optics and Optical Access Networks, Shanghai University, Shanghai 200072 (China); Peng, Gangding [Photonics and Optical Communications, School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney 2052, NSW (Australia); Wang, Tingyun, E-mail: tywang@mail.shu.edu.cn [Key Laboratory of Specialty Fiber Optics and Optical Access Networks, Shanghai University, Shanghai 200072 (China)

    2014-11-30

    Highlights: PbS-doped silica optical fiber materials have been fabricated by ALD technique. PbS-doped silica optical fiber materials are characterized through XPS, Raman and optical properties. The local structure model of PbS-3MR for the PbS-doped optical fiber materials is built, and its optical properties are investigated using DFT. The computed results of absorption and emission peaks are at 325.7 and 769.8 nm, which are good agreement with our experiment results. - Abstract: Optical properties of PbS-doped silica optical fiber materials and theoretical simulation are investigated. PbS is deposited on silica optical fiber materials by Atomic Layer Deposition (ALD) technique with Pb(tmhd){sub 2} and H{sub 2}S as Pb and S precursors, respectively. Its stoichiometry is confirmed by X-ray photoelectron spectroscopy (XPS). The valence states of S and Pb element are ?2 and +2, respectively. The Raman spectra further reveal that PbS has been doped into optical fiber materials almost without destroying irregular rings structure in silica material network. And there are distinct absorption bands at 248 and 352 nm. Fluorescence spectra are obtained with 330 and 350 nm pumping, two fluorescence peaks at 768 and 808 nm, respectively. In addition, the microstructure models for PbS-doped optical fiber materials are built on Gaussian09 platform, and its optical properties of the absorption and emission spectra are calculated using density functional theory (DFT) and time-dependent density functional theory (TDDFT) methods. There are obvious absorption and emission peaks at 325.7 and 769.8 nm, respectively, which are in good agreement with experiments.

  8. Characteristics of Photonic Bandgap Fibres with Hollow Core's Inner Surface Coated by a Layer Material

    International Nuclear Information System (INIS)

    Hollow core's inner surface coating in a photonic bandgap fibre (PBGF) is investigated by means of finite element method. The coat material and thickness-dependence dispersion curve and group velocity dispersion are numerically studied. The coating with materials of low index or small thickness will rise up the dispersion curve but will not induce surface modes. However, coating with materials of high index or big coat thickness will induce surface modes and avoided-crossings. By varying coat material's refractive index and thickness, the appearances of surface modes and avoided-crossings can be changed. It is found that the avoided-crossing can enormously enlarge the negative dispersion which can find applications in dispersion compensation. We numerically achieve a negative dispersion as large as -21416.15 ps/nm/km. The results give a physical insight into the propagation properties of PBGFs with the hollow core coated by a layer of material and are of crucial significance in the applications of PBGF coating

  9. Los Alamos MAWST software layered on Westinghouse Savannah River Company's nuclear materials accountability system

    International Nuclear Information System (INIS)

    The Los Alamos Safeguards Systems Group's Materials Accounting With Sequential Testing (MAWST) computer program was developed to fulfill DOE Order 5633.3B requiring that inventory-difference control limits be based on variance propagation or any other statistically valid technique. Westinghouse Savannah River Company (WSRC) developed a generic computerized accountability system, NucMAS, to satisfy accounting and reporting requirements for material balance areas. NucMAS maintains the calculation methods and the measurement information required to compute nuclear material transactions in elemental and isotopic masses by material type code. The Safeguards Systems Group designed and implemented to WSRC's specifications a software interface application, called NucMASloe. It is a layered product for NucMAS that automatically formats a NucMAS data set to a format compatible with MAWST and runs MAWST. This paper traces the development of NucMASloe from the Software Requirements through the testing and demonstration stages. The general design constraints are described as well as the difficulties encountered on interfacing an external software product (MAWST) with an existing classical accounting structure (NucMAS). The lessons learned from this effort, the design, and some of the software are directly applicable to the Local Area Network Material Accountability System (LANMAS) being sponsored by DOE

  10. The effect of gamma-irradiation on few-layered graphene materials

    Energy Technology Data Exchange (ETDEWEB)

    Ansn-Casaos, A., E-mail: alanson@icb.csic.es [Instituto de Carboqumica, ICB-CSIC, Miguel Luesma Castn 4, 50018 Zaragoza (Spain); Purtolas, J.A. [Department of Materials Science and Technology-EINA, Instituto de Investigacin en Ingeniera de Aragn, I3A, Universidad de Zaragoza, E-50018 Zaragoza (Spain); Pascual, F.J. [Department of Materials Science and Technology-EINA, Instituto de Investigacin en Ingeniera de Aragn, I3A, Universidad de Zaragoza, E-50018 Zaragoza (Spain); Centro Universitario de la Defensa de Zaragoza, Academia General Militar, Carretera de Huesca s/n, E-50090 Zaragoza (Spain); Hernndez-Ferrer, J. [Instituto de Carboqumica, ICB-CSIC, Miguel Luesma Castn 4, 50018 Zaragoza (Spain); Castell, P. [AITIIP Technological Center, Polgono Industrial Empresarium, C/Romero 12, 50720 Zaragoza (Spain); Benito, A.M.; Maser, W.K.; Martnez, M.T. [Instituto de Carboqumica, ICB-CSIC, Miguel Luesma Castn 4, 50018 Zaragoza (Spain)

    2014-05-01

    Highlights: The effect of ?-irradiation was studied on two graphene materials. Both graphene materials were examined in their oxidized and post-reduced forms. We comparatively characterized ?-irradiation and chemical reduction effects. Irradiation caused modifications in the graphene carbon lattice. Small changes in the oxygen content occurred during irradiation. - Abstract: The effect of ?-irradiation on the structure and composition of chemically synthesized few-layered graphene materials was studied. Fully oxidized graphene oxide and graphene nanoribbons, as well as their respective chemically post-reduced forms, were treated under ?-irradiation in an air-sealed environment. Three different irradiation doses of 60, 90 and 150 kGy were applied. Structure and composition of the irradiated materials were analyzed by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The XRD patterns were not affected by ?-irradiation, and small changes were observed in the FTIR and TGA results. However, significant modifications were detected by Raman spectroscopy and XPS, particularly in the Raman G/D band intensity ratios and in the C 1s XPS profiles. Comparatively, the changes in Raman and XPS spectra after ?-irradiation were even greater than those occurring during the chemical reduction of graphene oxides. Our results indicate that the graphene carbon lattice was strongly affected by ?-irradiation, but the materials experienced small variations in their oxygen content.

  11. The effect of gamma-irradiation on few-layered graphene materials

    International Nuclear Information System (INIS)

    Highlights: The effect of ?-irradiation was studied on two graphene materials. Both graphene materials were examined in their oxidized and post-reduced forms. We comparatively characterized ?-irradiation and chemical reduction effects. Irradiation caused modifications in the graphene carbon lattice. Small changes in the oxygen content occurred during irradiation. - Abstract: The effect of ?-irradiation on the structure and composition of chemically synthesized few-layered graphene materials was studied. Fully oxidized graphene oxide and graphene nanoribbons, as well as their respective chemically post-reduced forms, were treated under ?-irradiation in an air-sealed environment. Three different irradiation doses of 60, 90 and 150 kGy were applied. Structure and composition of the irradiated materials were analyzed by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The XRD patterns were not affected by ?-irradiation, and small changes were observed in the FTIR and TGA results. However, significant modifications were detected by Raman spectroscopy and XPS, particularly in the Raman G/D band intensity ratios and in the C 1s XPS profiles. Comparatively, the changes in Raman and XPS spectra after ?-irradiation were even greater than those occurring during the chemical reduction of graphene oxides. Our results indicate that the graphene carbon lattice was strongly affected by ?-irradiation, but the materials experienced small variations in their oxygen content

  12. Colloidal-chemical properties of layer silicate dispersions used for production of highly porous glass-ceramic materials

    International Nuclear Information System (INIS)

    We study the processes of structure formation in dispersions of layered silicate montmorillonite for the production of highly porous materials with the addition of glass powder by duplication of a polyurethane matrix. Rheological properties of dispersions were regulated by polyvinyl alcohol. It is established that the dense layer of glass powder is formed after the application of glass containing a dispersion on the surface of a polymer template. The thickness of this layer depends on the PVA concentration in the system.

  13. A fluidized layer of granular material used for the separation of particulate impurities in drinking water treatment

    OpenAIRE

    Pivokonsk, Martin; Bubkov, Petra; Hna?ukov, Petra; Knesl, Bohuslav

    2011-01-01

    This paper deals with the application of a fluidized layer of granular material (FLGM) for the direct separation of destabilized impurities during drinking water treatment. Further, it investigates the effect of operation parameters (fluidized layer grain size, technological arrangement, velocity gradient, retention time, dosage of destabilisation reagent and temperature) on the aggregation and separation efficiency of the layer. The tests were carried out in a pilot plant scale. Aluminium su...

  14. Cooperation of micro- and meso-porous carbon electrode materials in electric double-layer capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Cheng [State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun 130022, Jilin Province (China); Graduate University of Chinese Academy of Sciences, Beijing 100039 (China); Qi, Li; Wang, Hongyu [State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun 130022, Jilin Province (China); Yoshio, Masaki [Advanced Research Center, Saga University, 1341 Yoga-machi, Saga 840-0047 (Japan)

    2010-07-01

    The capacitive characteristics of micro- and meso-porous carbon materials have been compared in cyclic voltammetric studies and galvanostatic charge-discharge tests. Meso-porous carbon can keep certain high capacitance values at high scan rates, whereas micro-porous carbon possesses very high capacitance values at low scan rates but fades quickly as the scan rate rises up. For better performance of electric double-layer capacitors (EDLCs), the cooperative application of both kinds of carbon materials has been proposed in the following two ways: mixing both kinds of carbons in the same electrode or using the asymmetric configuration of carbon electrodes in the same EDLC. The cooperative effect on the electrochemical performance has also been addressed. (author)

  15. Electrochemical Effects of Atomic Layer Deposition on Cathode Materials for Lithium Batteries

    Science.gov (United States)

    Scott, Isaac David

    One of the greatest challenges of modern society is to stabilize a consistent energy supply that will meet our growing energy demand while decreasing the use of fossil fuels and the harmful green house gases which they produce. Developing reliable and safe solutions has driven research into exploring alternative energy sources for transportation including fuel cells, hydrogen storage, and lithium-ion batteries (LIBs). For the foreseeable future, though, rechargeable batteries appear to be the most practically viable power source. To deploy LIBs in next-generation vehicles, it is essential to develop electrodes with durability, high energy density, and high power. Unfortunately, the power capability of LIBs is generally hindered by Li+-ion diffusion in micrometer-sized materials and the formation of an insulating solid electrolyte interface (SEI) layer on the surface of the active material. In addition, degradation of the battery material due to chemical and electrochemical reactions with the electrolyte lead to both capacity fade and safety concerns both at room and higher temperatures. The current study focuses on mitigating these issues for high voltage cathode materials by both using nanoscale particles to improve Li+-ion diffusion and using ultrathin nanoscale coatings to protect the battery materials from undesirable side reactions. The electrode material is coated with Al2O3 using atomic layer deposition (ALD), which is a method to grow conformal thin films with atomic thickness (angstrom level control) using sequential, self-limiting surface reactions. First, nano-LiCoO 2 is employed to demonstrate the effectiveness of ALD coatings and demonstrates a profound increase in rate performance (>250% improvement) over generally employed micrometer-sized particles. Second, the cathode materials LiNi 0.8Co0.15Al0.05O2, LiNi0.33Mn 0.33Co0.33O2, LiMn2O4, and LiNi0.5Mn1.5O4 were used to demonstrate the benefits ALD coatings have on thermal runaway. The results show a decrease in exothermic reactions at elevated temperatures (>180 C) for the coated versus uncoated material. Third, impedance studies were carried out on LiNi0.5Mn1.5O 4 to study the kinetic effects the ALD layer has on battery performance. These studies show that despite Al2O3 being electrically resistive in the bulk; the ultrathin coatings do not impede battery reaction kinetics. Finally, ALD coatings were studied for use in Li-O2 batteries. The results from these studies provide new opportunities for the battery industry to design other novel electrodes that are highly durable, safe, and provide good power performance. It also demonstrates that many of the issues that are detrimental to LIBs may simply be addressed by employing the scalable technique of atomic layer deposition.

  16. Casimir Piston of Real Materials and its Application to Multi-Layer Models

    CERN Document Server

    Teo, L P

    2009-01-01

    In this article, we derive the formula for the Casimir force acting on a piston made of real material moving inside a perfectly conducting rectangular box. It is shown that by taking suitable limits, one recovers the formula for the Casimir force acting on a perfectly conducting piston or an infinitely permeable piston. Lipshitz formula for finite temperature Casimir force acting on parallel plates made of real materials is re-derived by considering the five-layer model in the context of piston approach. It is observed that the divergences of the Casimir force will only cancel under certain conditions, for example, when the regions separated by the plates are filled with isorefractive media.

  17. Holographic recording characteristics and applications of single-layer panchromatic dichromated gelatin material

    Science.gov (United States)

    Zhu, Jianhua; Xu, Min; Chen, Ligong; Guo, Yongkang; Guo, Lurong

    2005-09-01

    A high-quality single-layer panchromatic dichromated gelatin material is achieved successfully by employing new types of multi-color photosensitizers and photochemical promoters to conventional photo-crosslinking gelatin system. Its holographic recording characteristics such as spectral response, the photosensitivity of three primary colors, spectral selectivity of volume reflection hologram, angular and wavelength selectivity of volume transmission hologram, are studied in detail. Using red, green and blue lasers, namely three primary colors, the bright volume transmission and reflection holograms can be recorded on the panchromatic material at the exposure level of 30 mJ/cm2. Some preliminary results of space, angle and wavelength multiplexing holographic storage for storing multiple binary and grey-tone optical images, are also reported in this paper.

  18. Process for forming one or more substantially pure layers in substrate material using ion implantation

    International Nuclear Information System (INIS)

    This patent describes a process for forming a substantially pure, monocrystalline layer of an implantable element in a monocrystalline substrate. It comprises selecting an implantable element and a monocrystalline substrate to be implanted wherein, at the temperature to be used for the implantation and annealing; the solubilities of the implantable element and the substrate material in one another are less than 10 at. %; and no intermediate phases containing both the implantable element and the substrate material exist; implanting, at a temperature ranging from about -196 degrees C to about 10 degrees C below the melting point of the substrate, at least about 5 x 1016 atoms/cm2 of the implantable element in the substrate; and annealing the implanted substrate at a temperature ranging from about 20 degrees C to about 10 degrees C below the melting point of the substrate for a period of time of about 1 second to about 100 hours

  19. Novel magnetic materials prepared by electrodeposition techniques: arrays of nanowires and multi-layered microwires

    International Nuclear Information System (INIS)

    The fabrication process by electrodeposition routes and the study of general magnetic properties is reported for two types of nanostructured magnetic materials: (a) nickel-filled highly-ordered nanoporous alumina templates, and (b) electrodeposited Ni layers onto glass coated amorphous microwires. Arrays of Ni nanowires, about 30 nm in diameter and separated by about 100 nm, are obtained by electrodeposition into the pores of alumina membranes prepared by two-steps anodization process from highly pure aluminum substrates. Morphological studies have been performed by high resolution scanning electron microscopy (HRSEM). The study includes the optimization of preparation parameters and the magnetic characterization of the hexagonally arranged nanowire arrays, i.e. the influence of the pore diameter and the interwire distance on the coercivity of the whole nanowire array. On the other hand, multi-layered magnetic microwires have been prepared in the following sequence: a nanometric Au coat is first sputtered onto Pyrex coated FeSiB amorphous microwires followed by electrodeposition of a 500 nm thick Ni external cover. While in as-cast microwires the hysteresis loop is squared shaped (magnetic bistability), in the case of the multilayer microwire, a transverse magnetic anisotropy is induced when reducing the measuring temperature as a consequence of the stresses induced by the different thermal expansion coefficients of the various layers

  20. Responses of benthic macroinvertebrates to thin-layer disposal of dredged material in Mississippi Sound, USA.

    Science.gov (United States)

    Wilber, Dara H; Clarke, Douglas G; Rees, Susan I

    2007-01-01

    Benthic community responses to thin-layer disposal of dredged material were assessed at three sites in Mississippi Sound, USA. Community composition differed between disposal and reference sites (ANOSIM) for each disposal event. Oweniid sand worms, Amphinomid fire worms, and brittle stars (Ophiuriodea) contributed the most to community distinctions between disposal and reference sites (SIMPER), with higher abundances at the disposal sites. Total infaunal abundance was similar to pre-disposal and reference conditions within 3-10 months of thin-layer disposal. Distinctions in community composition between disposal and reference sites (nMDS) persisted throughout the 16-month study period, but were less pronounced at the site where sediment composition was unchanged by disposal. Size distributions of some taxa (e.g., gastropod and hemichordate) suggest adults recolonized the newly deposited sediments either through vertical migration or lateral immigration from adjacent areas. Thin-layer disposal offers a viable alternative to conventional open-water disposal practices and warrants further exploration for other areas with deeper bathymetries and different hydrodynamic regimes. PMID:17052734

  1. In Situ XRD Investigations on Structural Change of P2-Layered Materials during Electrochemical Sodiation/Desodiation

    DEFF Research Database (Denmark)

    Jung, Young Hwa; Johnsen, Rune E.; Christiansen, Ane Slland; Norby, Poul; Kim, Do Kyung

    Sodium layered oxides (NaxMO2) are attractive as positive electrode materials for rechargeable sodium-ion batteries (SIBs) due to high capacity, fast ionic diffusion and simple synthetic process. O3-layered lithium compounds have led successful commercialization of current lithium-ion batteries; ...

  2. A Method to Estimate the Dynamic Displacement and Stress of a Multi-layered Pavement with Bituminous or Concrete Materials

    Directory of Open Access Journals (Sweden)

    Zheng LU

    2014-12-01

    Full Text Available In this research work, a method to estimate the dynamic characteristics of a multilayered pavement with bituminous or concrete materials is proposed. A mechanical model is established to investigate the dynamic displacement and stress of the multi-layered pavement structure. Both the flexible and the rigid pavements, corresponding to bituminous materials and concrete materials, respectively, are studied. The theoretical solutions of the multi-layered pavement structure are deduced considering the compatibility condition at the interface of the structural layers. By introducing FFT (Fast Fourier Transform algorithm, some numerical results are presented. Comparisons of the theoretical and experimental result implied that the proposed method is reasonable in predicting the stress and displacement of a multi-layered pavement with bituminous or concrete materials. DOI: http://dx.doi.org/10.5755/j01.ms.20.4.6071

  3. Fabrication of scalable and structured tissue engineering scaffolds using water dissolvable sacrificial 3D printed moulds

    DEFF Research Database (Denmark)

    Mohanty, Soumyaranjan; Larsen, Layla Bashir; Trifol Guzman, Jon; Szabo, Peter; Burri, Harsha Vardhan Reddy; Canali, Chiara; Dufva, Martin; Emnéus, Jenny; Wolff, Anders

    2015-01-01

    One of the major challenges in producing large scale engineered tissue is the lack of ability to create large highly perfused scaffolds in which cells can grow at a high cell density and viability. Here, we explore 3D printed polyvinyl alcohol (PVA) as a sacrificial mould in a polymer casting...

  4. Sidetracked by trolleys: Why sacrificial moral dilemmas tell us little (or nothing) about utilitarian judgment

    Science.gov (United States)

    Kahane, Guy

    2015-01-01

    Research into moral decision-making has been dominated by sacrificial dilemmas where, in order to save several lives, it is necessary to sacrifice the life of another person. It is widely assumed that these dilemmas draw a sharp contrast between utilitarian and deontological approaches to morality, and thereby enable us to study the psychological and neural basis of utilitarian judgment. However, it has been previously shown that some sacrificial dilemmas fail to present a genuine contrast between utilitarian and deontological options. Here, I raise deeper problems for this research paradigm. Even when sacrificial dilemmas present a contrast between utilitarian and deontological options at a philosophical level, it is misleading to interpret the responses of ordinary folk in these terms. What is currently classified as utilitarian judgment does not in fact share essential features of a genuine utilitarian outlook, and is better explained in terms of commonsensical moral notions. When subjects deliberate about such dilemmas, they are not deciding between opposing utilitarian and deontological solutions, but engaging in a richer process of weighing opposing moral reasons. Sacrificial dilemmas therefore tell us little about utilitarian decision-making. An alternative approach to studying proto-utilitarian tendencies in everyday moral thinking is proposed. PMID:25791902

  5. New efficient preparation of arylzinc compounds from aryl halides using cobalt catalysis and sacrificial anode process

    Science.gov (United States)

    Gosmini; Rollin; Nedelec; Perichon

    2000-09-22

    Electroreduction of aryl-chlorides or -bromides in an electrochemical cell fitted with a sacrificial zinc anode and in the presence of cobalt halide associated with pyridine as ligand in DMF or acetonitrile as solvent affords the corresponding organozinc species in good yields. PMID:10987936

  6. Simplified method of analysis of sacrificial shield wall for pipe whip restraint load

    International Nuclear Information System (INIS)

    the purpose of this paper is to analyze the sacrificial shield wall for the pipe whip load which is particularly important for the safety analysis and failure predictions of concrete reactor pressure vessel. The location of the shield wall makes it a very important structure for the support of the pipe whip restraints. The sacrificial shield wall is a composite structural steel and plain concrete, open-ended cylindrical shell structure stiffened by stiffening rings and vertical stiffeners. The restraint reaction loads act over a small area and are assumed to be concentrated and local loads on the sacrificial shield wall. The response of the sacrificial shield wall to the restraint-reaction load is assessed in terms of local effects and overall structural response which can be treated separately but are interrelated in actuality. Due to the complex physical processes involved with the analysis, local effects are evaluated primarily by the application of ring theory and the overall structural response by the beam theory. Local effects are evaluated considering a sector (-4500) of a ring of mean radius 'a' and subjected to a concentrated (two-pulse loading) dynamic load of magnitude 'F' at center (theta=00). Overall effects are evaluated by considering a cantilever cylindrical beam of mean radius 'a'. An effective spring and effective mass are used to represent the most contributing ring mode from the ring analysis described earlier into the beam model. The results of the simplified approach are compared with the results by the bending theory of

  7. Radioactive Materials Monitoring on Superficial Layer Soils in Gyeongsangnam-Do

    International Nuclear Information System (INIS)

    In this paper, for the purpose of investigating the effects of artificial radioactive materials between 2012 and 2013 year, analysis on 80 superficial layer soils in total collected in industrial estates, farmlands, mining areas located in Gyeongsangnam-Do were conducted by using HPGe(High Purification Germanuim Gamma-ray Spectrometer). Before investigation, the calibrations on the HPGe detector were conducted twice a year with a view to confirming the normal operation of measuring equipment. And, based on the calibration results, the effects of artificial radioactive materials were analyzed. Also, to ensure reliability on analysis results, a comparative analysis was conducted using the analysis results presented by KINS(Korea Institute of Nuclear Safety), and using the MDA(Minimum Detectable Activity) values specified by related regulations. In this investigation, 131I, 134Cs, 137Cs, and so on, were selected as examination nuclides. By analyzing results on total 80 superficial layer soils, because all of nuclides satisfied the MDA requirements specified in the Nuclear Safety Committee Notification No. 2012-5, it is judged that there is no problem related with the reliability of the analyzed results. Also, 134Cs was detected infinitesimally only in the industrial complex soil sample of Tongyeong region. Therefore, it is judged that continuously monitoring on the soil samples of Gyeongsangnam-Do is required from now on

  8. Assessment of doses caused by electrons in thin layers of tissue-equivalent materials, using MCNP.

    Science.gov (United States)

    Heide, Bernd

    2013-10-01

    Absorbed doses caused by electron irradiation were calculated with Monte Carlo N-Particle transport code (MCNP) for thin layers of tissue-equivalent materials. The layers were so thin that the calculation of energy deposition was on the border of the scope of MCNP. Therefore, in this article application of three different methods of calculation of energy deposition is discussed. This was done by means of two scenarios: in the first one, electrons were emitted from the centre of a sphere of water and also recorded in that sphere; and in the second, an irradiation with the PTB Secondary Standard BSS2 was modelled, where electrons were emitted from an (90)Sr/(90)Y area source and recorded inside a cuboid phantom made of tissue-equivalent material. The speed and accuracy of the different methods were of interest. While a significant difference in accuracy was visible for one method in the first scenario, the difference in accuracy of the three methods was insignificant for the second one. Considerable differences in speed were found for both scenarios. In order to demonstrate the need for calculating the dose in thin small zones, a third scenario was constructed and simulated as well. The third scenario was nearly equal to the second one, but a pike of lead was assumed to be inside the phantom in addition. A dose enhancement (caused by the pike of lead) of ?113 % was recorded for a thin hollow cylinder at a depth of 0.007 cm, which the basal-skin layer is referred to in particular. Dose enhancements between 68 and 88 % were found for a slab with a radius of 0.09 cm for all depths. All dose enhancements were hardly noticeable for a slab with a cross-sectional area of 1 cm(2), which is usually applied to operational radiation protection. PMID:23576794

  9. Material transport in a convective surface mixed layer under weak wind forcing

    Science.gov (United States)

    Mensa, Jean A.; zgkmen, Tamay M.; Poje, Andrew C.; Imberger, Jrg

    2015-12-01

    Flows in the upper ocean mixed layer are responsible for the transport and dispersion of biogeochemical tracers, phytoplankton and buoyant pollutants, such as hydrocarbons from an oil spill. Material dispersion in mixed layer flows subject to diurnal buoyancy forcing and weak winds (| u10 | = 5m s-1) are investigated using a non-hydrostatic model. Both purely buoyancy-forced and combined wind- and buoyancy-forced flows are sampled using passive tracers, as well as 2D and 3D particles to explore characteristics of horizontal and vertical dispersion. It is found that the surface tracer patterns are determined by the convergence zones created by convection cells within a time scale of just a few hours. For pure convection, the results displayed the classic signature of Rayleigh-Benard cells. When combined with a wind stress, the convective cells become anisotropic in that the along-wind length scale gets much larger than the cross-wind scale. Horizontal relative dispersion computed by sampling the flow fields using both 2D and 3D passive particles is found to be consistent with the Richardson regime. Relative dispersion is an order of magnitude higher and 2D surface releases transition to Richardson regime faster in the wind-forced case. We also show that the buoyancy-forced case results in significantly lower amplitudes of scale-dependent horizontal relative diffusivity, kD(?), than those reported by Okubo (1970), while the wind- and buoyancy-forced case shows a good agreement with Okubo's diffusivity amplitude, and the scaling is consistent with Richardson's 4/3rd law, kD ? ?4/3. These modeling results provide a framework for measuring material dispersion by mixed layer flows in future observational programs.

  10. Gigantic swelling of inorganic layered materials: a bridge to molecularly thin two-dimensional nanosheets.

    Science.gov (United States)

    Geng, Fengxia; Ma, Renzhi; Ebina, Yasuo; Yamauchi, Yusuke; Miyamoto, Nobuyoshi; Sasaki, Takayoshi

    2014-04-01

    Platy microcrystals of a typical layered material, protonated titanate, have been shown to undergo an enormous degree of swelling in aqueous solutions of various amines, including tertiary amines, quaternary ammonium hydroxides, and primary amines. Introducing these solutions expanded the crystal gallery height by up to ~100-fold. Through systematic analysis, we determined that ammonium ion intercalation is predominantly affected by the acid-base equilibrium and that the degree of swelling or inflow of H2O is controlled by the osmotic pressure balance between the gallery and the solution environment, both of which are relatively independent of electrolyte identity but substantially dependent on molarity. In solutions of tertiary amines and quaternary ammonium hydroxides, the uptake of ammonium ions increases nearly linearly with increasing external concentration before reaching a saturation plateau, i.e., ~40% relative to the cation-exchange capacity of the crystals used. The only exception is tetrabutylammonium ions, which yield a lower saturation value, ~30%, owing to steric effects. The swelling behaviors in some primary amine solutions differ as a result of the effect of attractive forces between amine solute molecules on the solution osmotic pressure. Although the swelling is essentially colligative in nature, the stability of the resultant swollen structure is heavily dependent on the chemical nature of the guest ions. Intercalated ions of higher polarity and smaller size help stabilize the swollen structure, whereas ions of lower polarity and larger size lead readily to exfoliation. The insight gained from this study sheds new light on both the incorporation of guest molecules into a gallery of layered structures in general and the exfoliation of materials into elementary single-layer nanosheets. PMID:24635385

  11. Material and Doping Dependence of the Nodal and Anti-Nodal Dispersion Renormalizations in Single- and Multi-Layer Cuprates

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, S.; /Waterloo U. /SLAC; Lee, W.S.; /Stanford U., Geballe Lab. /SLAC; Nowadnick, E.A.; /SLAC /Stanford U., Phys. Dept.; Moritz, B.; /SLAC /North Dakota U.; Shen, Z.-X.; /Stanford U., Geballe Lab. /SLAC /Stanford U., Phys. Dept. /Stanford U., Appl. Phys. Dept.; Devereaux, T.P.; /Stanford U., Geballe Lab. /SLAC

    2010-02-15

    In this paper we present a review of bosonic renormalization effects on electronic carriers observed from angle-resolved photoemission spectra in the cuprates. Specifically, we discuss the viewpoint that these renormalizations represent coupling of the electrons to the lattice and review how materials dependence, such as the number of CuO{sub 2} layers, and doping dependence can be understood straightforwardly in terms of several aspects of electron-phonon coupling in layered correlated materials.

  12. MODELLING OF ACOUSTIC EMISSION SIGNALS FOR THE CASE OF MATERIAL SURFACE LAYERS DISTRACTION IN THE PROCESS OF FRICTION

    Directory of Open Access Journals (Sweden)

    Sergey F. Filonenko

    2008-02-01

    Full Text Available The obtained data of the resulting acoustic signals emission at the prevailing mechanism of the material surface layer wear under friction have been considered. It has been shown that the form and parameters of the acoustic emission resulting signals depend on the time of the initiation of type-I or type-II secondary structures fracture (rotation velocity of friction pair, as well as the stressed-deformed state of the materials surface layers of friction pairs.

  13. Distinguishing crystallite size effects from those of structural disorder on the powder X-ray diffraction patterns of layered materials

    Indian Academy of Sciences (India)

    Sylvia Britto; Sumy Joseph; P Vishnu Kamath

    2010-09-01

    Both crystallite size effects and structural disorder contribute to the broadening of lines in the powder X-ray diffraction (PXRD) patterns of layered materials. Stacking faults, in particular, are ubiquitous in layered materials and aside from broadening also induce peaks due to select reflections to shift away from the Bragg positions. The effect of structural disorder has to be suitably discounted before the application of the Scherrer formula for the estimation of crystallite size.

  14. Fluorine uptake into the human tooth from a thin layer of F-releasing material

    International Nuclear Information System (INIS)

    Using the proton induced gamma-ray emission (PIGE) method (TIARA, Japan), we have studied fluorine (F) distribution in the human tooth under various conditions. Here, we report F uptake into the human tooth from a thin layer of F-releasing low viscous resin (FLVR). Crowns of human teeth were horizontally cut and the dentin of the cut surface was first covered with four kinds of FLVR (FL-Bond, Reactmer Bond, Xeno Bond, and Protect Liner F; thickness, 50-150 μm) according to the manufacturers' instructions. Non-F-releasing and F-releasing filling resins were also hardened, on the cut surfaces of crowns covered with four kinds of FLVR thin layers. The type of the non-F-releasing filling materials used was LITE FIL IIP: G1-A (FL-Bond and LITE FIL IIP), G2-A (Reactmer Bond and LITE FIL IIP), G3-A (Xeno Bond and LITE FIL IIP), and G4-A (Protect Liner F and LITE FIL IIP). The types of F-releasing filling materials used were G1-B (FL-Bond and Beautifil), G2-B (Reactmer Bond and Reactmer Paste), G3-B (Xeno Bond and Xeno CF Paste), and G4-B (Protect Liner F and Teethmate F-1). Treatment and measurements of specimens were the same as previously reported [H. Yamamoto, M. Nomahci, K. Yasuda, Y. Iwami, S. Ebisu, N. Yamamoto, T. Sakai, T. Kamiya, Nucl. Instr. and Meth. B 210 (2003) 388]. F uptake from specimens following one month of application was estimated from 2-D maps. F penetration was observed in all teeth of G1-A-G4-A groups. The maximum values of F concentration in each tooth and F penetration depth were larger for larger F concentrations in FLVR. FLVR was useful for the F uptake into the tooth, and the F distribution near the thin layer of FLVR depended on the materials used. Between G1-A and G1-B or G4-A and G4-B, the F uptake was significantly different. We were able to obtain fundamental data, which were useful for the analysis of F transportation relating to prevention of caries

  15. Fluorine uptake into the human tooth from a thin layer of F-releasing material

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, H. [Department of Restorative Dentistry and Endodontology, Graduate School of Dentistry, Osaka University, 1-8 Yamadaoka, Suita, Osaka, 565-0871 (Japan)]. E-mail: yhiroko@dent.osaka-u.ac.jp; Nomachi, M. [Graduate School of Science, Osaka University, Toyonaka, Osaka, 560-0043 (Japan); Yasuda, K. [Wakasa Wan Energy Research Center, Tsuruga, Fukui, 914-0192 (Japan); Iwami, Y. [Department of Restorative Dentistry and Endodontology, Graduate School of Dentistry, Osaka University, 1-8 Yamadaoka, Suita, Osaka, 565-0871 (Japan); Ebisu, S. [Department of Restorative Dentistry and Endodontology, Graduate School of Dentistry, Osaka University, 1-8 Yamadaoka, Suita, Osaka, 565-0871 (Japan); Komatsu, H. [Graduate School of Dental Medicine, Hokkaido University, Sapporo, Hokkaido, 060-8585 (Japan); Sakai, T. [Advanced Radiation Technology Center, JAERI, Takasaki, Gunma, 370-1292 (Japan); Kamiya, T. [Advanced Radiation Technology Center, JAERI, Takasaki, Gunma, 370-1292 (Japan)

    2007-07-15

    Using the proton induced gamma-ray emission (PIGE) method (TIARA, Japan), we have studied fluorine (F) distribution in the human tooth under various conditions. Here, we report F uptake into the human tooth from a thin layer of F-releasing low viscous resin (FLVR). Crowns of human teeth were horizontally cut and the dentin of the cut surface was first covered with four kinds of FLVR (FL-Bond, Reactmer Bond, Xeno Bond, and Protect Liner F; thickness, 50-150 {mu}m) according to the manufacturers' instructions. Non-F-releasing and F-releasing filling resins were also hardened, on the cut surfaces of crowns covered with four kinds of FLVR thin layers. The type of the non-F-releasing filling materials used was LITE FIL IIP: G1-A (FL-Bond and LITE FIL IIP), G2-A (Reactmer Bond and LITE FIL IIP), G3-A (Xeno Bond and LITE FIL IIP), and G4-A (Protect Liner F and LITE FIL IIP). The types of F-releasing filling materials used were G1-B (FL-Bond and Beautifil), G2-B (Reactmer Bond and Reactmer Paste), G3-B (Xeno Bond and Xeno CF Paste), and G4-B (Protect Liner F and Teethmate F-1). Treatment and measurements of specimens were the same as previously reported [H. Yamamoto, M. Nomahci, K. Yasuda, Y. Iwami, S. Ebisu, N. Yamamoto, T. Sakai, T. Kamiya, Nucl. Instr. and Meth. B 210 (2003) 388]. F uptake from specimens following one month of application was estimated from 2-D maps. F penetration was observed in all teeth of G1-A-G4-A groups. The maximum values of F concentration in each tooth and F penetration depth were larger for larger F concentrations in FLVR. FLVR was useful for the F uptake into the tooth, and the F distribution near the thin layer of FLVR depended on the materials used. Between G1-A and G1-B or G4-A and G4-B, the F uptake was significantly different. We were able to obtain fundamental data, which were useful for the analysis of F transportation relating to prevention of caries.

  16. Cleaning of conveyor belt materials using ultrasound in a thin layer of water.

    Science.gov (United States)

    Axelsson, L; Holck, A; Rud, I; Samah, D; Tierce, P; Favre, M; Kure, C F

    2013-08-01

    Cleaning of conveyor belts in the food industry is imperative for preventing the buildup of microorganisms that can contaminate food. New technologies for decreasing water and energy consumption of cleaning systems are desired. Ultrasound can be used for cleaning a wide range of materials. Most commonly, baths containing fairly large amounts of water are used. One possibility to reduce water consumption is to use ultrasonic cavitation in a thin water film on a flat surface, like a conveyor belt. In order to test this possibility, a model system was set up, consisting of an ultrasound transducer/probe with a 70-mm-diameter flat bottom, operating at 19.8 kHz, and contaminated conveyor belt materials in the form of coupons covered with a thin layer of water or water with detergent. Ultrasound was then applied on the water surface at different power levels (from 46 to 260 W), exposure times (10 and 20 s), and distances (2 to 20 mm). The model was used to test two different belt materials with various contamination types, such as biofilms formed by bacteria in carbohydrate- or protein-fat-based soils, dried microorganisms (bacteria, yeasts, and mold spores), and allergens. Ultrasound treatment increased the reduction of bacteria and yeast by 1 to 2 log CFU under the most favorable conditions compared with water or water-detergent controls. The effect was dependent on the type of belt material, the power applied, the exposure time, and the distance between the probe and the belt coupon. Generally, dried microorganisms were more easily removed than biofilms. The effect on mold spores was variable and appeared to be species and material dependent. Spiked allergens were also efficiently removed by using ultrasound. The results in this study pave the way for new cleaning designs for flat conveyor belts, with possibilities for savings of water, detergent, and energy consumption. PMID:23905796

  17. Enhanced photoconductivity in organic single-layered photoreceptors with bipolar charge transport materials

    International Nuclear Information System (INIS)

    The organic single-layered photoreceptors (SLPRs) consisting of polycarbonate (PC) matrix containing dispersed N,N'-diethyl-4-aminobenzaldehyde-1-phenyl-1'-(?-naphthyl)-hydrazone (BAH) and 2,4,7-trinitrylfluorenone (TNF) as bipolar charge (hole and electron) transport materials, as well as oxotitanium phthalocyanine (TiOPc) as charge generation materials (CGMs), were prepared. The influence of organic electron transport material (ETM) on the photosensitivity in the photoreceptors was investigated. It was found that small amount of TNF (TNF/BAH ?0.005) could improve the photosensitivity of photoreceptors greatly, i.e. the enhanced photoconductive effect, but the further increase of TNF concentration would lead to the decline of the photosensitivity. Differential scanning calorimeter (DSC), UV-Vis and cyclic voltammograms (CV) study showed that the enhanced photoconductivity might be resulted from the improvement of the separation efficiency of electron-hole pairs, and the decline of photosensitivity was due to the formation of the charge transfer complex (CTC) of TNF-BAH

  18. Synthesis of polyaniline/carbon black hybrid hollow microspheres by layer-by-layer assembly used as electrode materials for supercapacitors

    International Nuclear Information System (INIS)

    Graphical abstract: The polyaniline/carbon black hybrid hollow microspheres with a external diameter about 3.0 ?m were prepared via layer-by-layer assembly technique, and the electrochemical tests showed that polyaniline/carbon black hybrid hollow microspheres would be a potential candidates of electrode materials for supercapacitors with high specific capacitance. Highlights: ? The PAn/CB hybrid hollow microspheres were prepared via LBL technique. ? The specific capacitance increased with the increase in the adsorption of PAn and CB. ? The hollow structure and synergistic effect of shell enhance the specific capacitance. ? The PAn/CB hollow microsphere is a candidate of electrode material for supercapacitor. -- Abstract: The polyaniline (PAn)/carbon black (CB) hybrid hollow microspheres have been prepared by the layer-by-layer assembly technique alternately adsorbing of PAn and CB onto the polystyrene sulfonate microsphere templates after etching the templates by dialysis. The hollow structure of the obtained hybrid hollow microspheres was characterized by transmission electron microscopy, which indicated that the external diameter of the hollow microspheres was about 3.0 ?m. When the hybrid hollow microsphere were used as the electrode material for supercapacitors, the results showed that the specific capacitance increased with the increase in the adsorption numbers of PAn and CB, which was as high as 532 F g?1 at a chargedischarge current density of 10 mA cm?2 in 1.0 M H2SO4 electrolyte after alternately adsorbing of PAn and CB six times

  19. Few-layered MoSe2 nanosheets as an advanced electrode material for supercapacitors.

    Science.gov (United States)

    Balasingam, Suresh Kannan; Lee, Jae Sung; Jun, Yongseok

    2015-09-21

    We report the synthesis of few-layered MoSe2 nanosheets using a facile hydrothermal method and their electrochemical charge storage behavior. A systematic study of the structure and morphology of the as-synthesized MoSe2 nanosheets was performed. The downward peak shift in the Raman spectrum and the high-resolution transmission electron microscopy images confirmed the formation of few-layered nanosheets. The electrochemical energy-storage behavior of MoSe2 nanosheets was also investigated for supercapacitor applications in a symmetric cell configuration. The MoSe2 nanosheet electrode exhibited a maximum specific capacitance of 198.9 F g(-1) and the symmetric device showed 49.7 F g(-1) at a scan rate of 2 mV s(-1). A capacitance retention of approximately 75% was observed even after 10 000 cycles at a high charge-discharge current density of 5 A g(-1). The two-dimensional MoSe2 nanosheets exhibited a high specific capacitance and good cyclic stability, which makes it a promising electrode material for supercapacitor applications. PMID:26239099

  20. Oscillatory motion in layered materials: graphene, boron nitride, and molybdenum disulfide

    Science.gov (United States)

    Ye, Zhijiang; Otero-de-la-Roza, Alberto; Johnson, Erin R.; Martini, Ashlie

    2015-04-01

    Offset-driven self-retraction and oscillatory motion of bilayer graphene has been observed experimentally and is potentially relevant for nanoscale technological applications. In a previous article, we showed that friction between laterally offset graphene layers is controlled by roughness and proposed a simple reduced-order model based on density-functional theory (DFT) and molecular dynamics (MD) data, with which predictions on the experimental size-scale could be made. In this article, we extend our study to other layered materials, with emphasis on boron nitride (BN) and molybdenum disulfide (MoS2). Using MD and DFT simulations of these systems and a generalized version of the reduced-order model, we predict that BN will exhibit behavior similar to graphene (heavily-damped oscillation with a decay rate that increases with roughness) and that MoS2 shows no oscillatory behavior even in the absence of roughness. This is attributed to the higher energy barrier for sliding in MoS2 as well as the surface structure. Our generalized reduced-order model provides a guide to predicting and tuning experimental oscillation behavior using a few parameters that can be derived from simulation data.

  1. Non-destructive characterization of surface layers on non ferromagnetic materials

    International Nuclear Information System (INIS)

    Electromagnetic nondestructive techniques are usually applied to solve many inspection problems in industry. In particular, eddy currents are used for the detection of defects and the characterization of physical properties of metallic materials and components. One such application is the measurement of thickness of non conductive layers on a conducting substrate. A laboratory device for the quantitative determination of those thicknesses was developed at our laboratory. It works in the range from 0 to 100 ?m and was calibrated with a micro metre screw. This task involved the design and construction of the sensors their characterization (working frequency, resolution, sensitivity, etc.) and the setup of the mechanical system and the electronic signal generation and measurement circuit. (author)

  2. Local structure of layered oxide electrode materials for lithium-ion batteries.

    Science.gov (United States)

    Bareo, J; Lei, C H; Wen, J G; Kang, S-H; Petrov, I; Abraham, D P

    2010-03-12

    Li-ion batteries are promising candidates for electrical energy storage in applications ranging from portable electronics to hybrid and electric vehicles. In this context, layered compounds in the Li(1+delta)(TM(x)Mn(1-x))(1-delta)O(2) family (TM = transition metal) have received much attention due to their high capacity and stability. In this Research News article we describe recent advances on structural characterization of Li-ion electrode materials using state-of-the-art electron microscopy. Direct evidence of the monoclinic nature of Li(2)MnO(3) has been provided. It has been demonstrated that differences in Z-contrast imaging between Li(2)MnO(3) and LiTMO(2) may be used to screen samples for phase separation in the 10-100 nm scale. PMID:20401936

  3. Zinc oxide grown by atomic layer deposition - a material for novel 3D electronics

    Energy Technology Data Exchange (ETDEWEB)

    Guziewicz, Elzbieta; Krajewski, Tomasz A.; Wachnicki, Lukasz; Luka, Grzegorz; Domagala, Jaroslaw Z.; Paszkowicz, Wojciech; Kowalski, Bogdan J.; Witkowski, Bartlomiej S.; Suchocki, Andrzej [Institute of Physics, Polish Academy of Sciences, Warsaw (Poland); Godlewski, Marek [Institute of Physics, Polish Academy of Sciences, Warsaw (Poland); Department of Mathematics and Natural Sciences, College of Science Cardinal Stefan Wyszynski University, Warsaw (Poland); Duzynska, Anna [Department of Mathematics and Natural Sciences, College of Science Cardinal Stefan Wyszynski University, Warsaw (Poland)

    2010-07-15

    Last years we observe a booming interest in materials which can be successfully grown at low temperature limits showing good structural and electrical characteristics. This trend is closely related to the novel three-dimensional (3D) architecture which seems to be a prospective solution for miniaturization of electronic devices after the 22 nm node. We demonstrate that electrical parameters of ZnO grown by the atomic layer deposition (ALD) method at low temperature limit (100-200 C) fulfil requirements for 3D electronic devices, because electron carrier mobility is above 10 cm{sup 2}/Vs and n concentration at the level of 1 x 10{sup 17} cm{sup -3}. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  4. The measurement of surface erosion of D9 material during laser ablation process by thin layer activation technique

    International Nuclear Information System (INIS)

    Thin layer activation (TLA) has been applied to study the surface erosion of D9 stainless steel material of fuel tube used in Indian nuclear power reactor, in micron order during laser ablation process. A beam of 15 MeV proton was chosen to produce a thin layer of activity in the surface (depth of activation ?428.6 ?m) of D9 material. The laser ablation of active sample was carried out with Nd-YAG laser (wavelength 1064 nm) with suitable parameters for satisfactory decontamination and also ablation. The surface loss of D9 material was less than 50 nm for the laser energy chosen for decontamination processes. (author)

  5. Transfer Printed P3HT/PCBM Photoactive Layers: From Material Intermixing to Device Characteristics.

    Science.gov (United States)

    Abdellah, Alaa; Falco, Aniello; Schwarzenberger, Ulrich; Scarpa, Giuseppe; Lugli, Paolo

    2016-02-01

    The fabrication of organic electronic devices involving complex stacks of solution-processable functional materials has proven challenging. Significant material intermixing often occurs as a result of cross-solubility and postdeposition treatments, rendering the realization of even the simplest bilayer architectures rather cumbersome. In this study we investigate the feasibility of a dry transfer printing process for producing abrupt bilayer organic photodiodes (OPDs) and the effect of thermal annealing on the integrity of the bilayer. The process involves the transfer of readily deposited thin films of poly(3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-phenyl C61 butyric acid methyl ester (PCBM) using a polydimethylsiloxane (PDMS) stamp. Fabricated structures are characterized by means of cross-sectional scanning electron microscopy (SEM), UV/vis absorption spectroscopy, and time-of-flight secondary ion mass spectrometry (TOF-SIMS). Joint consideration of all results unveils abrupt interfaces with no thermal treatment applied and significant material intermixing for samples annealed above 100 C. The role of the thermally assisted intermixing in determining the performance of complete devices is evaluated through the comparison of J-V characteristics and external quantum efficiencies (EQEs) of identical photodiodes subject to different annealing conditions. It is shown that the performance of such devices approaches the one of bulk heterojunction photodiodes upon thermal annealing at 140 C for 5 min. Our results demonstrate that transfer printing is a reliable and simple process for the realization of functional multilayers, paving the way for organic electronic devices incorporating complex stacks. It further contributes to a fundamental understanding of material composition within photoactive layers by elucidating the process of thermally assisted intermixing. PMID:26754413

  6. In Situ XRD Investigations on Structural Change of P2-Layered Materials during Electrochemical Sodiation/Desodiation

    DEFF Research Database (Denmark)

    Jung, Young Hwa; Johnsen, Rune E.

    2014-01-01

    Sodium layered oxides (NaxMO2) are attractive as positive electrode materials for rechargeable sodium-ion batteries (SIBs) due to high capacity, fast ionic diffusion and simple synthetic process. O3-layered lithium compounds have led successful commercialization of current lithium-ion batteries; as a result, rich experiences for structural studies of O3-layered compounds have been accumulated over the past decades. For sodium layered oxides, however, P2-layered compounds have been reported for better cyclability and structural stability during electrochemical reactions than O3-structure. Therefore, systematic studies on P2-layered materials for SIBs are highly required. In this study, we report the structural and electrochemical property of P2-NaxFeyMnyCo1-2yO2 synthesized by simple solid state reaction. The X-ray diffraction pattern of as-synthesized powder is indexed as a hexagonal lattice (P63/mmc, No.194), which is identical to P2-layered structure. The structural changes in hexagonal P2-layered oxides have been investigated during electrochemical sodiation/desodiation by in-situ synchrotron X-ray diffractions of a capillary based micro battery cell. From the result of in-situ studies, the initial layered structure is maintained from 2.0 to 4.0 V vs. Na+/Na during first desodiation. The phase transformation is observed over the 4.0 V, but the original P2 structure is completely restored at the following sodiation process. The relationship between structural and electrochemical properties of this P2-layered material will be discussed.

  7. Sacrificial Tamper Slows Down Sample Explosion in FLASH Diffraction Experiments

    International Nuclear Information System (INIS)

    Intense and ultrashort x-ray pulses from free-electron lasers open up the possibility for near-atomic resolution imaging without the need for crystallization. Such experiments require high photon fluences and pulses shorter than the time to destroy the sample. We describe results with a new femtosecond pump-probe diffraction technique employing coherent 0.1 keV x rays from the FLASH soft x-ray free-electron laser. We show that the lifetime of a nanostructured sample can be extended to several picoseconds by a tamper layer to dampen and quench the sample explosion, making <1 nm resolution imaging feasible.

  8. Stacking sequence determines Raman intensities of observed interlayer shear modes in 2D layered materials - A general bond polarizability model

    Science.gov (United States)

    Luo, Xin; Lu, Xin; Cong, Chunxiao; Yu, Ting; Xiong, Qihua; Ying Quek, Su

    2015-10-01

    2D layered materials have recently attracted tremendous interest due to their fascinating properties and potential applications. The interlayer interactions are much weaker than the intralayer bonds, allowing the as-synthesized materials to exhibit different stacking sequences, leading to different physical properties. Here, we show that regardless of the space group of the 2D materials, the Raman frequencies of the interlayer shear modes observed under the typical configuration blue shift for AB stacked materials, and red shift for ABC stacked materials, as the number of layers increases. Our predictions are made using an intuitive bond polarizability model which shows that stacking sequence plays a key role in determining which interlayer shear modes lead to the largest change in polarizability (Raman intensity); the modes with the largest Raman intensity determining the frequency trends. We present direct evidence for these conclusions by studying the Raman modes in few layer graphene, MoS2, MoSe2, WSe2 and Bi2Se3, using both first principles calculations and Raman spectroscopy. This study sheds light on the influence of stacking sequence on the Raman intensities of intrinsic interlayer modes in 2D layered materials in general, and leads to a practical way of identifying the stacking sequence in these materials.

  9. Stacking sequence determines Raman intensities of observed interlayer shear modes in 2D layered materials A general bond polarizability model

    Science.gov (United States)

    Luo, Xin; Lu, Xin; Cong, Chunxiao; Yu, Ting; Xiong, Qihua; Ying Quek, Su

    2015-01-01

    2D layered materials have recently attracted tremendous interest due to their fascinating properties and potential applications. The interlayer interactions are much weaker than the intralayer bonds, allowing the as-synthesized materials to exhibit different stacking sequences, leading to different physical properties. Here, we show that regardless of the space group of the 2D materials, the Raman frequencies of the interlayer shear modes observed under the typical configuration blue shift for AB stacked materials, and red shift for ABC stacked materials, as the number of layers increases. Our predictions are made using an intuitive bond polarizability model which shows that stacking sequence plays a key role in determining which interlayer shear modes lead to the largest change in polarizability (Raman intensity); the modes with the largest Raman intensity determining the frequency trends. We present direct evidence for these conclusions by studying the Raman modes in few layer graphene, MoS2, MoSe2, WSe2 and Bi2Se3, using both first principles calculations and Raman spectroscopy. This study sheds light on the influence of stacking sequence on the Raman intensities of intrinsic interlayer modes in 2D layered materials in general, and leads to a practical way of identifying the stacking sequence in these materials. PMID:26469313

  10. Natural convection around a horizontal solid cylinder wrapped with a layer of fibrous or porous material

    International Nuclear Information System (INIS)

    Heat losses in duct flow and heat transfer enhancement are investigated through an analysis of natural convection about a horizontal cylinder with a porous or fibrous coating. The porous substrate may be used for two purposes. According to its properties, it may be employed as an insulating material or as a means to surface augmentation. An optimization study is then carried out in order to find the best conditions that allow good thermal insulation or heat transfer rate improvement. The flow motion and heat transfer coefficient are predicted for various conditions. The results show that an efficient insulation which means less than 10% in heat losses is obtained for a porous layer thickness of 0.8x tube diameter and a permeability corresponding to Da ? 10-7. Nevertheless, there is a Darcy number limit above which convection must be accounted for. Porous or fibrous materials may also be used as a heat transfer augmentation technique. To achieve this goal, porous media with high permeability and/or high effective thermal conductivity must be selected

  11. Improving quality of textile wastewater with organic materials as multi soil layering

    Science.gov (United States)

    Supriyadi; Widijanto, H.; Pranoto; Dewi, AK

    2016-02-01

    On agricultural land, fresh water is needed especially for irrigation. Alternative ways to fulfill needs of fresh water is by utilizing wastewater from industry. Wastewater that produced in the industry in Surakarta is over flowing especially textile wastewater. Wastewater that produced from industry has many pollutants that affected decreasing fresh water quality for irrigation. Multi Soil Layering (MSL) is one of method that utilize the soil ability as main media by increasing its function of soil structure to purify wastewater, so it does not contaminate the environment and reusable. This research was purposed to know affectivity of organic materials (such as rice straw, baggase, sawdust, coconut fibre, and corncob) and dosage (5%, 10% and 25%) in MSL, also get alternative purification ways with easy and cheaper price as natural adsorbent. This study using field and laboratory experiment. The result shows that MSL can be an alternative method of purification of wastewater. The appropriate composition of organic materials that can be used as adsorbent is MSL with wood sawdust 10% dosage because it can increase pH, decrease the number of Cr, ammonia, and phosphate but less effective to decrease BOD and COD.

  12. Fabrication of Meso-Porous Sintered Metal Thin Films by Selective Etching of Silica Based Sacrificial Template

    Directory of Open Access Journals (Sweden)

    Ludovic F. Dumee

    2014-08-01

    Full Text Available Meso-porous metal materials have enhanced surface energies offering unique surface properties with potential applications in chemical catalysis, molecular sensing and selective separation. In this paper, commercial 20 nm diameter metal nano-particles, including silver and copper were blended with 7 nm silica nano-particles by shear mixing. The resulted powders were cold-sintered to form dense, hybrid thin films. The sacrificial silica template was then removed by selective etching in 12 wt% hydrofluoric acid solutions for 15 min to reveal a purely metallic meso-porous thin film material. The impact of the initial silica nano-particle diameter (720 nm as well as the sintering pressure (520tonm?2 and etching conditions on the morphology and properties of the final nano-porous thin films were investigated by porometry, pyknometery, gas and liquid permeation and electron microscopy. Furthermore, the morphology of the pores and particle aggregation during shear mixing were assessed through cross-sectioning by focus ion beam milling. It is demonstrated that meso-pores ranging between 50 and 320 nm in average diameter and porosities up to 47% can be successfully formed for the range of materialstested.

  13. Comparative Study of Charge Trapping Type SOI-FinFET Flash Memories with Different Blocking Layer Materials

    Directory of Open Access Journals (Sweden)

    Yongxun Liu

    2014-06-01

    Full Text Available The scaled charge trapping (CT type silicon on insulator (SOI FinFET flash memories with different blocking layer materials of Al2O3 and SiO2 have successfully been fabricated, and their electrical characteristics including short-channel effect (SCE immunity, threshold voltage (Vt variability, and the memory characteristics have been comparatively investigated. It was experimentally found that the better SCE immunity and a larger memory window are obtained by introducing a high-k Al2O3 blocking layer instead of a SiO2 blocking layer. It was also confirmed that the variability of Vt before and after one program/erase (P/E cycle is almost independent of the blocking layer materials.

  14. Chemical Fouling Reduction of a Submersible Steel Spectrophotometer in Estuarine Environments Using a Sacrificial Zinc Anode.

    Science.gov (United States)

    Tait, Zachary S; Thompson, Megan; Stubbins, Aron

    2015-07-01

    The availability of in situ spectrophotometers, such as the S::CAN spectro::lyser, has expanded the possibilities for high-frequency water quality data collection. However, biological and chemical fouling can degrade the performance of in situ spectrophotometers, especially in saline environments with rapid flow rates. A complex freshwater washing system has been previously designed to reduce chemical fouling for the S::CAN spectro::lyser spectrophotometer. In the current study, we present a simpler, cheaper alternative: the attachment of a sacrificial zinc anode. Results are presented detailing the S::CAN spectro::lyser performance with and without the addition of the sacrificial anode. Attachment of the zinc anode provided efficient corrosion protection during 2-wk deployments in a highly dynamic (average tidal range, 2.5 m) saline tidal saltmarsh creek at Groves Creek, Skidaway Institute of Oceanography, Savannah, GA. PMID:26437114

  15. Monitoring the Startup of a Sacrificial Concrete Sewer for Odor Control

    DEFF Research Database (Denmark)

    Nielsen, Asbjørn Haaning; Vollertsen, Jes

    2014-01-01

    The use of a sacrificial concrete sewer for controlling sulphide-related odour downstream of a pressure sewer was investigated in this study. The investigated sewer is located in a rural catchment and is intended to alleviate odour problems downstream of a small diameter pressure sewer with...... extended retention time. For the purpose of the study, a 50-m long sacrificial concrete gravity sewer was constructed using a high alkalinity concrete pipe. The monitoring campaign reported in this paper covers the first 9 months of operation. The results clearly demonstrate the ability of the system to...... (95 percentile) were reduced from several hundred ppmv in the discharge manhole to approximately 10 ppmv at the downstream end. Thus, the odour potential has been significantly reduced. A visual inspection of the system revealed that even after 9 months of operation not all of the concrete surfaces...

  16. Processing of Nanosensors Using a Sacrificial Template Approach

    Science.gov (United States)

    Biaggi-Labiosa, Azlin M.; Hunter, Gary W.

    2012-01-01

    A new microsensor fabrication approach has been demonstrated based upon the use of nanostructures as templates. The fundamental idea is that existing nanostructures, such as carbon nano tubes or biological structures, have a material structure that can be used advantageously in order to provide new sensor systems but lack the advantages of some materials to, for example, operate at high temperatures. The approach is to start with a template using nanostructures such as a carbon nanotube. This template can then be coated by an oxide material with higher temperature capabilities. Upon heating in air, the carbon nanotube template is burned off, leaving only the metal oxide nanostructure. The resulting structure has a combination of the crystal structure and surface morphology of the carbon nanotube, combined with the material durability and hightemperature- sensing properties of the metal oxide. Further, since the metal oxide nanocrystals are deposited on the carbon nanotube, after burn-off what is left is a metal oxide porous nanostructure. This makes both the interior and the exterior of this nano structured sensor available for gas species detection. This, in effect, increases the surface area available for sensing, which has been shown in the past to significantly increase sensor performance.

  17. Understanding the key parameters for the rational design of layered oxide materials by composite sol-gel procedures

    OpenAIRE

    Ould-Chikh, Samy; Brodusch, Nicolas; Crozet, Nathalie; Hemati, Mehrdji; Rouleau, Loc

    2013-01-01

    Previous works have well demonstrated that particle size of the filler used in layered oxide formulation is the first important parameter and must be decreased below 5 ?m (Agrafiotis, 1999-2000 [10]). But once the particle size is set what are the next formulation parameters to highlight as critical? How do we improve cohesion and adhesion of the coatings? To highlight the key parameters driving the quality of coating, a model layered oxide material was prepared inside a pan granulator. The m...

  18. Structural and Chemical Evolution of Li- and Mn-rich Layered Cathode Material

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Jianming; Xu, Pinghong; Gu, Meng; Xiao, Jie; Browning, Nigel D.; Yan, Pengfei; Wang, Chong M.; Zhang, Jiguang

    2015-02-24

    Lithium (Li)- and manganese-rich (LMR) layered-structure materials are very promising cathodes for high energy density lithium-ion batteries. However, their voltage fading mechanism and its relationships with fundamental structural changes are far from being sufficiently understood. Here we report the detailed phase transformation pathway in the LMR cathode (Li[Li0.2Ni0.2Mn0.6]O2) during cycling for the samples prepared by hydro-thermal assistant method. It is found the transformation pathway of LMR cathode is closely correlated to its initial structure and preparation conditions. The results reveal that LMR cathode prepared by HA approach experiences a phase transformation from the layered structure to a LT-LiCoO2 type defect spinel-like structure (Fd-3m space group) and then to a disordered rock-salt structure (Fm-3m space group). The voltage fade can be well correlated with the Li ion insertion into octahedral sites, rather than tetrahedral sites, in both defect spinel-like structure and disordered rock-salt structure. The reversible Li insertion/removal into/from the disordered rock-salt structure is ascribed to the Li excess environment that can satisfy the Li percolating in the disordered rock-salt structure despite the increased kinetic barrier. Meanwhile, because of the presence of a great amount of oxygen vacancies, a significant decrease of Mn valence is detected in the cycled particle, which is below that anticipated for a potentially damaging Jahn-Teller distortion (+3.5). Clarification of the phase transformation pathway, cation redistribution, oxygen vacancy and Mn valence change undoubtedly provides insights into a profound understanding on the voltage fade, and capacity degradation of LMR cathode. The results also inspire us to further enhance the reversibility of LMR cathode via improving its surface structural stability.

  19. Magnesium-Based Sacrificial Anode Cathodic Protection Coatings (Mg-Rich Primers) for Aluminum Alloys

    OpenAIRE

    Michael D. Blanton; James W. Rawlins; Shashi S. Pathak; Sharathkumar K. Mendon

    2012-01-01

    Magnesium is electrochemically the most active metal employed in common structural alloys of iron and aluminum. Mg is widely used as a sacrificial anode to provide cathodic protection of underground and undersea metallic structures, ships, submarines, bridges, decks, aircraft and ground transportation systems. Following the same principle of utilizing Mg characteristics in engineering advantages in a decade-long successful R&D effort, Mg powder is now employed in organic coatings (termed ...

  20. EFFECTIVE LAYERED MATERIALS WITH TRANZITION ZONE FROM NANOPARTICLES CREATED IN VOLUME OF COMPOSITE / ??????????? ???????? ????????? ? ?????????? ????? ?? ??????????, ????????????? ? ?????? ?????????

    Directory of Open Access Journals (Sweden)

    Sokov V. N. / ????? ?????? ??????????

    2014-10-01

    Full Text Available The authors describe the developed energy-effective and speedy technology of three-layered monolithic products with developed specific surface area and nanostructured transition zone between layers created by hydro thermal and power field / ??????? ????????????? ????????????????? ? ?????????? ?????????? ??????????? ?????????? ??????? ? ???????? ???????? ???????????? ? ????????????????????? ?????????? ????? ????? ??????, ??????????? ????????????????? ?????

  1. 'Utilitarian' judgments in sacrificial moral dilemmas do not reflect impartial concern for the greater good.

    Science.gov (United States)

    Kahane, Guy; Everett, Jim A C; Earp, Brian D; Farias, Miguel; Savulescu, Julian

    2015-01-01

    A growing body of research has focused on so-called 'utilitarian' judgments in moral dilemmas in which participants have to choose whether to sacrifice one person in order to save the lives of a greater number. However, the relation between such 'utilitarian' judgments and genuine utilitarian impartial concern for the greater good remains unclear. Across four studies, we investigated the relationship between 'utilitarian' judgment in such sacrificial dilemmas and a range of traits, attitudes, judgments and behaviors that either reflect or reject an impartial concern for the greater good of all. In Study 1, we found that rates of 'utilitarian' judgment were associated with a broadly immoral outlook concerning clear ethical transgressions in a business context, as well as with sub-clinical psychopathy. In Study 2, we found that 'utilitarian' judgment was associated with greater endorsement of rational egoism, less donation of money to a charity, and less identification with the whole of humanity, a core feature of classical utilitarianism. In Studies 3 and 4, we found no association between 'utilitarian' judgments in sacrificial dilemmas and characteristic utilitarian judgments relating to assistance to distant people in need, self-sacrifice and impartiality, even when the utilitarian justification for these judgments was made explicit and unequivocal. This lack of association remained even when we controlled for the antisocial element in 'utilitarian' judgment. Taken together, these results suggest that there is very little relation between sacrificial judgments in the hypothetical dilemmas that dominate current research, and a genuine utilitarian approach to ethics. PMID:25460392

  2. Utilitarian judgments in sacrificial moral dilemmas do not reflect impartial concern for the greater good

    Science.gov (United States)

    Kahane, Guy; Everett, Jim A.C.; Earp, Brian D.; Farias, Miguel; Savulescu, Julian

    2015-01-01

    A growing body of research has focused on so-called utilitarian judgments in moral dilemmas in which participants have to choose whether to sacrifice one person in order to save the lives of a greater number. However, the relation between such utilitarian judgments and genuine utilitarian impartial concern for the greater good remains unclear. Across four studies, we investigated the relationship between utilitarian judgment in such sacrificial dilemmas and a range of traits, attitudes, judgments and behaviors that either reflect or reject an impartial concern for the greater good of all. In Study 1, we found that rates of utilitarian judgment were associated with a broadly immoral outlook concerning clear ethical transgressions in a business context, as well as with sub-clinical psychopathy. In Study 2, we found that utilitarian judgment was associated with greater endorsement of rational egoism, less donation of money to a charity, and less identification with the whole of humanity, a core feature of classical utilitarianism. In Studies 3 and 4, we found no association between utilitarian judgments in sacrificial dilemmas and characteristic utilitarian judgments relating to assistance to distant people in need, self-sacrifice and impartiality, even when the utilitarian justification for these judgments was made explicit and unequivocal. This lack of association remained even when we controlled for the antisocial element in utilitarian judgment. Taken together, these results suggest that there is very little relation between sacrificial judgments in the hypothetical dilemmas that dominate current research, and a genuine utilitarian approach to ethics. PMID:25460392

  3. Development of a Biocompatible Layer-by-Layer Film System Using Aptamer Technology for Smart Material Applications

    OpenAIRE

    Amanda Foster; Maria C. DeRosa

    2014-01-01

    Aptamers are short, single-stranded nucleic acids that fold into well-defined three dimensional (3D) structures that allow for binding to a target molecule with affinities and specificities that can rival or in some cases exceed those of antibodies. The compatibility of aptamers with nanostructures such as thin films, in combination with their affinity, selectivity, and conformational changes upon target interaction, could set the foundation for the development of novel smart materials. In th...

  4. New PACVD-hard material layers for wear protection of high-speed steel

    Energy Technology Data Exchange (ETDEWEB)

    Bartsch, K.; Leonhardt, A. [Institut fuer Festkoerper- und Werkstofforschung Dresden e.V. (Germany); Langer, U.; Kuenanz, K. [Technische Universitaet Dresden, Institut fuer Produktionstechnik, D-01062, Dresden (Germany)

    1997-10-01

    TiC/C, (Ti,Al)N and (Ti,Al)C layers have been deposited employing PACVD under dc-pulse discharge conditions and were investigated with respect to their composition and structure. The layer hardness can be varied in a large range by varying the Al content and the C content in the case of the TiC/C layers. By incorporation of C in TiC layers the friction coefficient can be decreased. Analogously to TiN layers, oxygen impurities cause a drastic hardness decrease in (Ti,Al)N layers. It was demonstrated that by multilayer deposition including TiN, TiCN and (Ti,Al)N with single layers of 100-300 nm thickness the layer stress decreases by about 50%, which results in an increase in layer adhesion. PACVD (Ti,Al)N and TiC/C layers yielded comparable or even better results than PVD layers in drilling 41Cr4 steel and the Al-alloy AlSi9Cu3. (orig.) 11 refs.

  5. Preparation and biological evaluation of a fibroblast growth factor-2-apatite composite layer on polymeric material

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Kenkichi; Kamitakahara, Masanobu; Ioku, Koji [Graduate School of Environmental Studies, Tohoku University, Aoba 6-6-20, Aramaki, Aoba-ku, Sendai 980-8579 (Japan); Oyane, Ayako [Nanosystem Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Central 4, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8562 (Japan); Hyodo, Koji [Human Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-2-1 Namiki, Tsukuba, Ibaraki 305-8564 (Japan); Ito, Atsuo; Sogo, Yu, E-mail: a-oyane@aist.go.j [Human Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Central 6, 1-1-1, Higashi, Tsukuba, Ibaraki 305-8566 (Japan)

    2010-12-15

    A polymeric percutaneous device with good biocompatibility and resistance to bacterial infection is required clinically. In this study, a fibroblast growth factor-2 (FGF-2)-hydroxyapatite (HAp) composite layer (FHAp layer) was formed on the surfaces of ethylene-vinyl alcohol copolymer (EVOH) specimens using a coating process in a supersaturated calcium phosphate solution supplemented with FGF-2. FGF-2 in the FHAp layer retained its biological activity to promote proliferation of fibroblasts. The EVOH specimens coated with HAp and FHAp layers were percutaneously implanted in the scalp of rats. Not only the HAp layer but also the FHAp layer showed good biocompatibility, and FGF-2 showed no harmful effects on the skin tissue responses to the implanted specimen as long as 14 d. No significantly higher infection resistance was verified for the FHAp layer over the HAp layer, although an FHAp layer coated on a metallic percutaneous device for bone fixation demonstrated higher resistance to bacterial infection over an HAp layer in the previous study. The efficacy of FHAp layers coated on percutaneous implants in resistance to bacterial infection depends on physical factors including fixation condition, stiffness and movement of implants.

  6. Preparation and biological evaluation of a fibroblast growth factor-2-apatite composite layer on polymeric material.

    Science.gov (United States)

    Sasaki, Kenkichi; Oyane, Ayako; Hyodo, Koji; Ito, Atsuo; Sogo, Yu; Kamitakahara, Masanobu; Ioku, Koji

    2010-12-01

    A polymeric percutaneous device with good biocompatibility and resistance to bacterial infection is required clinically. In this study, a fibroblast growth factor-2 (FGF-2)-hydroxyapatite (HAp) composite layer (FHAp layer) was formed on the surfaces of ethylene-vinyl alcohol copolymer (EVOH) specimens using a coating process in a supersaturated calcium phosphate solution supplemented with FGF-2. FGF-2 in the FHAp layer retained its biological activity to promote proliferation of fibroblasts. The EVOH specimens coated with HAp and FHAp layers were percutaneously implanted in the scalp of rats. Not only the HAp layer but also the FHAp layer showed good biocompatibility, and FGF-2 showed no harmful effects on the skin tissue responses to the implanted specimen as long as 14 d. No significantly higher infection resistance was verified for the FHAp layer over the HAp layer, although an FHAp layer coated on a metallic percutaneous device for bone fixation demonstrated higher resistance to bacterial infection over an HAp layer in the previous study. The efficacy of FHAp layers coated on percutaneous implants in resistance to bacterial infection depends on physical factors including fixation condition, stiffness and movement of implants. PMID:20966534

  7. Preparation and biological evaluation of a fibroblast growth factor-2-apatite composite layer on polymeric material

    International Nuclear Information System (INIS)

    A polymeric percutaneous device with good biocompatibility and resistance to bacterial infection is required clinically. In this study, a fibroblast growth factor-2 (FGF-2)-hydroxyapatite (HAp) composite layer (FHAp layer) was formed on the surfaces of ethylene-vinyl alcohol copolymer (EVOH) specimens using a coating process in a supersaturated calcium phosphate solution supplemented with FGF-2. FGF-2 in the FHAp layer retained its biological activity to promote proliferation of fibroblasts. The EVOH specimens coated with HAp and FHAp layers were percutaneously implanted in the scalp of rats. Not only the HAp layer but also the FHAp layer showed good biocompatibility, and FGF-2 showed no harmful effects on the skin tissue responses to the implanted specimen as long as 14 d. No significantly higher infection resistance was verified for the FHAp layer over the HAp layer, although an FHAp layer coated on a metallic percutaneous device for bone fixation demonstrated higher resistance to bacterial infection over an HAp layer in the previous study. The efficacy of FHAp layers coated on percutaneous implants in resistance to bacterial infection depends on physical factors including fixation condition, stiffness and movement of implants.

  8. Thin layer activation of non-metallic materials by using nuclear implantation

    International Nuclear Information System (INIS)

    Nuclear implantation of the cyclotron produced 7Be isotope was used for labeling of plastic and other materials that cannot be activated in nuclear wear measurements. In our experiments boron of natural composition was used in the form of a NiBSi metallic-glass foil as implantation target through the natB(p,x)7Be nuclear reactions. Kapton (C22H10O5N2) and beryllium targets are also suitable by using a 3He beam [through 12C(3He,2?)7Be and 9Be(3He,?n)7Be reactions, respectively] to produce a high flux of radioactive 7Be in order to implant a very thin surface layer of the secondary target. The chosen secondary target should have a composition which does not contain elements which can be activated by the bombarding beam. This condition was controlled separately by the bombardment with the same beam. This control-irradiation is also useful to make corrections for possible interferences. Based on our early and recent experiences we have chosen Be as implantation target, having the most proper conditions for nuclear implantation. (orig.)

  9. Low temperature silicon dioxide by thermal atomic layer deposition: Investigation of material properties

    Science.gov (United States)

    Hiller, D.; Zierold, R.; Bachmann, J.; Alexe, M.; Yang, Y.; Gerlach, J. W.; Stesmans, A.; Jivanescu, M.; Mller, U.; Vogt, J.; Hilmer, H.; Lper, P.; Knle, M.; Munnik, F.; Nielsch, K.; Zacharias, M.

    2010-03-01

    SiO2 is the most widely used dielectric material but its growth or deposition involves high thermal budgets or suffers from shadowing effects. The low-temperature method presented here (150 C) for the preparation of SiO2 by thermal atomic layer deposition (ALD) provides perfect uniformity and surface coverage even into nanoscale pores, which may well suit recent demands in nanoelectronics and nanotechnology. The ALD reaction based on 3-aminopropyltriethoxysilane, water, and ozone provides outstanding SiO2 quality and is free of catalysts or corrosive by-products. A variety of optical, structural, and electrical properties are investigated by means of infrared spectroscopy, UV-Vis spectroscopy, secondary ion mass spectrometry, capacitance-voltage and current-voltage measurements, electron spin resonance, Rutherford backscattering, elastic recoil detection analysis, atomic force microscopy, and variable angle spectroscopic ellipsometry. Many features, such as the optical constants (n, k) and optical transmission and surface roughness (1.5 ), are found to be similar to thermal oxide quality. Rapid thermal annealing (RTA) at 1000 C is demonstrated to significantly improve certain properties, in particular by reducing the etch rate in hydrofluoric acid, oxide charges, and interface defects. Besides a small amount of OH groups and a few atomic per mille of nitrogen in the oxide remaining from the growth and curable by RTA no impurities could be traced. Altogether, the data point to a first reliable low temperature ALD-growth process for silicon dioxide.

  10. Characterization of material properties of soft solid thin layers with acoustic radiation force and wave propagation.

    Science.gov (United States)

    Urban, Matthew W; Nenadic, Ivan Z; Qiang, Bo; Bernal, Miguel; Chen, Shigao; Greenleaf, James F

    2015-10-01

    Evaluation of tissue engineering constructs is performed by a series of different tests. In many cases it is important to match the mechanical properties of these constructs to those of native tissues. However, many mechanical testing methods are destructive in nature which increases cost for evaluation because of the need for additional samples reserved for these assessments. A wave propagation method is proposed for characterizing the shear elasticity of thin layers bounded by a rigid substrate and fluid-loading, similar to the configuration for many tissue engineering applications. An analytic wave propagation model was derived for this configuration and compared against finite element model simulations and numerical solutions from the software package Disperse. The results from the different models found very good agreement. Experiments were performed in tissue-mimicking gelatin phantoms with thicknesses of 1 and 4?mm and found that the wave propagation method could resolve the shear modulus with very good accuracy, no more than 4.10% error. This method could be used in tissue engineering applications to monitor tissue engineering construct maturation with a nondestructive wave propagation method to evaluate the shear modulus of a material. PMID:26520332

  11. A sodium layered manganese oxides as 3 V cathode materials for secondary lithium batteries

    International Nuclear Information System (INIS)

    The synthesis of a new anhydrous sodium manganese oxide ?-Na0.66MnO2.13 obtained via a sol-gel process in organic medium is reported. The partial and limited removal of sodium ions from the layered host lattice (hexagonal symmetry; a = 2.84 A, c = 11.09 A) allows to get a high and stable specific capacity of 180 mAh g-1 at C/20 in the cycling limits 4.3/2 V with a mean working voltage of 3 V without the emergence of a spinel phase. By introducing acetylene black in solution during the sol-gel reaction, a composite material containing 8 wt.% AB has been obtained. The rate capability is shown to be significantly improved leading to an increase of the available specific capacity with for instance 200 and 90 mAh g-1 at C/20 and C rate. This effect is ascribed to a better electronic contact between particles and/or the modification of the oxide surface which makes the intercalation process more homogeneous and more efficient

  12. Compound surface-plasmon-polariton waves guided by a thin metal layer sandwiched between a homogeneous isotropic dielectric material and a periodically multilayered isotropic dielectric material

    CERN Document Server

    Chiadini, Francesco; Scaglione, Antonio; Lakhtakia, Akhlesh

    2015-01-01

    Multiple p- and s-polarized compound surface plasmon-polariton (SPP) waves at a fixed frequency can be guided by a structure consisting of a metal layer sandwiched between a homogeneous isotropic dielectric (HID) material and a periodic multilayered isotropic dielectric (PMLID) material. For any thickness of the metal layer, at least one compound SPP wave must exist. It possesses the p-polarization state, is strongly bound to the metal/HID interface when the metal thickness is large but to both metal/dielectric interfaces when the metal thickness is small. When the metal layer vanishes, this compound SPP wave transmutes into a Tamm wave. Additional compound SPP waves exist, depending on the thickness of the metal layer, the relative permittivity of the HID material, and the period and the composition of the PMLID material. Some of these are p polarized, the others being s polarized. All of them differ in phase speed, attenuation rate, and field profile, even though all are excitable at the same frequency. The...

  13. Determination of interfacial layers in high - k ALD nanolaminate materials by ARXPS and SRXPS measurements

    International Nuclear Information System (INIS)

    The interfacial layers of high dielectric constant (high-k) nanolaminate films are here explored. Problems concerning ALD nanolaminate layers deals mainly with lack of accurate methods to determine in depth profile of few nm thick stacks. Modified angle resolved XPS (ARXPS) and synchrotron radiation XPS(SRXPS) are proposed as methods suitable in layer profiling. Studied stacks containing ZrO/HfO or AlO/ZrO, were prepared on Si substrates by atomic layer deposition (ALD). Two sets of experiments were covered. First dealt with initial growth (up to 20 cycles, with thickness d<2 nm) of AlO/ZrO and included layer by layer insitu investigation by SRXPS. Second experiment refer to industrial grown ZrO/HfO films (d?3 nm) processed with various parameters resulting in both, layer by layer and homogenous depositions. For those samples ex situ XPS, with angle dependent variation of probing depth, measurements were covered. By comparing obtained intensity ratios for different angles with computational developed stack model it was found that no simple layer by layer but some intermixing growth occurred including interaction with silicon substrate.

  14. Determination of interfacial layers in high - k ALD nanolaminate materials by ARXPS and SRXPS measurements.

    Energy Technology Data Exchange (ETDEWEB)

    Wyrodek, Jakub; Tallarida, Massimo; Schmeisser, Dieter [Brandenburgische Technische Universitaet, Angewandte Physik-Sensorik, Cottbus (Germany); Weisheit, Martin [GLOBALFOUNDRIES, Dresden (Germany)

    2010-07-01

    The interfacial layers of high dielectric constant (high-k) nanolaminate films are here explored. Problems concerning ALD nanolaminate layers deals mainly with lack of accurate methods to determine in depth profile of few nm thick stacks. Modified angle resolved XPS (ARXPS) and synchrotron radiation XPS(SRXPS) are proposed as methods suitable in layer profiling. Studied stacks containing ZrO/HfO or AlO/ZrO, were prepared on Si substrates by atomic layer deposition (ALD). Two sets of experiments were covered. First dealt with initial growth (up to 20 cycles, with thickness d<2 nm) of AlO/ZrO and included layer by layer insitu investigation by SRXPS. Second experiment refer to industrial grown ZrO/HfO films (d{proportional_to}3 nm) processed with various parameters resulting in both, layer by layer and homogenous depositions. For those samples ex situ XPS, with angle dependent variation of probing depth, measurements were covered. By comparing obtained intensity ratios for different angles with computational developed stack model it was found that no simple layer by layer but some intermixing growth occurred including interaction with silicon substrate.

  15. Layer by Layer Ex-Situ Deposited Cobalt-Manganese Oxide as Composite Electrode Material for Electrochemical Capacitor.

    Science.gov (United States)

    Rusi; Chan, P Y; Majid, S R

    2015-01-01

    The composite metal oxide electrode films were fabricated using ex situ electrodeposition method with further heating treatment at 300C. The obtained composite metal oxide film had a spherical structure with mass loading from 0.13 to 0.21 mg cm(-2). The structure and elements of the composite was investigated using X-ray diffraction (XRD) and energy dispersive X-ray (EDX). The electrochemical performance of different composite metal oxides was studied by cyclic voltammetry (CV) and galvanostatic charge-discharge (CD). As an active electrode material for a supercapacitor, the Co-Mn composite electrode exhibits a specific capacitance of 285 Fg(-1) at current density of 1.85 Ag(-1) in 0.5 M Na2SO4 electrolyte. The best composite electrode, Co-Mn electrode was then further studied in various electrolytes (i.e., 0.5 M KOH and 0.5 M KOH/0.04 M K3Fe(CN) 6 electrolytes). The pseudocapacitive nature of the material of Co-Mn lead to a high specific capacitance of 2.2 x 10(3) Fg(-1) and an energy density of 309 Whkg(-1) in a 0.5 M KOH/0.04 M K3Fe(CN) 6 electrolyte at a current density of 10 Ag(-1). The specific capacitance retention obtained 67% of its initial value after 750 cycles. The results indicate that the ex situ deposited composite metal oxide nanoparticles have promising potential in future practical applications. PMID:26158447

  16. Hybrid magnetic/superconducting materials obtained by insertion of a single-molecule magnet into TaS2 layers

    International Nuclear Information System (INIS)

    A material in which superconducting and magnetic properties coexist is synthesized by the intercalation of single-molecule magnets into the layered structure of a group V metal dichalcogenide. A molecule-based/solid-state hybrid strategy is here employed, proving as a promising chemical approach for preparing new materials in which superconductivity coexists with different molecule-intrinsic functionalities. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. Numerical simulation of phase change material composite wallboard in a multi-layered building envelope

    International Nuclear Information System (INIS)

    Highlights: ? A numerical method to study the heat transfer through a PCM composite wallboard is presented. ? PCM wallboard can reduce energy consumption and shift peak electricity load. ? There is an optimal location for the PCM wallboard in the building envelop. ? The PCM wallboard performance depends on weather conditions. - Abstract: Phase change materials (PCMs) have the capability to store/release massive latent heat when undergoing phase change. When impregnated or encapsulated into wallboard or concrete systems, PCMs can greatly enhance their thermal energy storage capacity and effective thermal mass. When used in the building envelope PCM wallboard has the potential to improve building operation by reducing the energy requirement for maintaining thermal comfort, downsizing the AC/heating equipment, and shifting the peak load from the electrical grid. In this work we numerically studied the potential of PCM on energy saving for residential homes. For that purpose we solved the one-dimensional, transient heat equation through the multi-layered building envelope using the CrankNicolson discretization scheme. A source term is incorporated to account for the thermal-physical properties of the composite PCM wallboard. Using this code we examined a PCM composite wallboard incorporated into the walls and roof of a typical residential building across various climate zones. The PCM performance was studied under all seasonal conditions using the latest typical meteorological year (TMY3) data for exterior boundary conditions. Our simulations show that PCM performance highly depends on the weather conditions, emphasizing the necessity to choose different PCMs at different climate zones. Comparisons were also made between different PCM wallboard locations. Our work shows that there exists an optimal location for PCM placement within building envelope dependent upon the resistance values between the PCM layer and the exterior boundary conditions. We further identified the energy savings potential by comparing the performance of the PCM wallboard against the performance of a building envelope without PCM. Our study shows that PCM composite wallboard can reduce the energy consumption in summer and winter and can shift the peak electricity load in the summer

  18. Thermal stress in a bi-material assembly with a 'piecewise-continuous' bonding layer: theorem of three axial forces

    International Nuclear Information System (INIS)

    We consider a bi-material assembly with a 'piecewise-continuous' bonding layer. The layer is characterized by different elastic constants of its 'pieces' (segments) and is assumed to be thin. Young's moduli of all the 'pieces' of the bonding layer are significantly lower than the moduli of the adherend materials. In such a situation the coefficient of thermal expansion (CTE) of the bonding material need not be accounted for. Only the interfacial compliance of the bonding layer is important. This is indeed the case for the majority of electronic, opto-electronic or photonic assemblies. We consider the situation when the assembly is manufactured at an elevated temperature and is subsequently cooled down to a low (say, room) temperature. The objective of the analysis is to develop a simple, easy-to-use and physically meaningful analytical ('mathematical') predictive model for the evaluation of the interfacial shearing stresses that arise at the boundaries of the 'pieces' (segments) of the bonding layer and at the assembly edge. The basic equation is obtained for the thermally induced forces acting in the adherends' cross-sections that correspond to the boundaries between the dissimilar portions of the bonding layer. This equation has the form of the theorem of three (bending) moments in the theory of multi-span beams lying on separate simple supports and could therefore be called the 'theorem of three axial forces'. We show, as an illustration, how this equation could be employed to design a bi-material assembly with an inhomogeneous bonding layer and with low interfacial shearing stresses. Low shearing stresses will certainly result in lower peeling stresses as well. The numerical example is carried out for an assembly with a relatively high-modulus bonding material in its mid-portion (aimed primarily at providing good adhesion and, if necessary, good heat transfer as well) and a low-modulus material in its peripheral portions (aimed primarily at bringing down the interfacial stresses). The maximum interfacial shearing stress in the assembly with the inhomogeneous bonding layer turned out to be only about 30% of the maximum shearing stress in an assembly with a homogeneous bonding layer having throughout its length the same modulus as the bonding material in the mid-portion of an assembly with an inhomogeneous bond. We would like to emphasize that the inhomogeneous bonding material addressed in this analysis does not necessarily have to be an epoxy one. Many other bonding materials with different moduli in the mid-portion and at the peripheral portions of the assembly could be considered for various practical applications. For instance, a high-modulus solder material such as, say, a tin-silver-copper (SAC) solder can be employed in the mid-portion of an assembly and a low-modulus solder (e.g. an indium-based alloy) at its peripheral portions. In other applications a high-modulus solder material could be considered for the mid-portion of the assembly and a low-modulus epoxy adhesive at its peripheral portions. We would also like to point out that the developed concept can be easily generalized for the situations when the bonding material is not a continuous one, but is of the ball-grid-array (BGA) or a pad-grid-array (PGA) type. Our concept could also be easily generalized for a two-dimensional case, for the situation when bending deformations should be accounted for, for non-uniform distribution of temperature (i.e. for assemblies with temperature gradients in the through-thickness and/or in the longitudinal direction), for situations when time-dependent effects (visco-elasticity, creep, stress relaxation) in the bonding material are important and for numerous other more complicated and practically important situations that might be encountered in engineering practice.

  19. Multi-oxide active layer deposition using Applied Materials Pivot array coater for high-mobility metal oxide TFT

    Science.gov (United States)

    Park, Hyun Chan; Scheer, Evelyn; Witting, Karin; Hanika, Markus; Bender, Marcus; Hsu, Hao Chien; Yim, Dong Kil

    2015-09-01

    By controlling a thin indium tin oxide (ITO), indium zinc oxide interface layer between gate insulator and indium gallium zinc oxide (IGZO), the thin-film transistor (TFT) performance can reach higher mobility as conventional IGZO as well as superior stability. For large-area display application, Applied Materials static PVD array coater (Applied Materials GmbH & Co. KG, Alzenau, Germany) using rotary targets has been developed to enable uniform thin layer deposition in display industry. Unique magnet motion parameter optimization in Pivot sputtering coater is shown to provide very uniform thin ITO layer to reach TFT performance with high mobility, not only on small scale, but also on Gen8.5 (2500 2200 mm glass size) production system.

  20. Elimination of initial stress-induced curvature in a micromachined bi-material composite-layered cantilever

    Science.gov (United States)

    Liu, Ruiwen; Jiao, Binbin; Kong, Yanmei; Li, Zhigang; Shang, Haiping; Lu, Dike; Gao, Chaoqun; Chen, Dapeng

    2013-09-01

    Micro-devices with a bi-material-cantilever (BMC) commonly suffer initial curvature due to the mismatch of residual stress. Traditional corrective methods to reduce the residual stress mismatch generally involve the development of different material deposition recipes. In this paper, a new method for reducing residual stress mismatch in a BMC is proposed based on various previously developed deposition recipes. An initial material film is deposited using two or more developed deposition recipes. This first film is designed to introduce a stepped stress gradient, which is then balanced by overlapping a second material film on the first and using appropriate deposition recipes to form a nearly stress-balanced structure. A theoretical model is proposed based on both the moment balance principle and total equal strain at the interface of two adjacent layers. Experimental results and analytical models suggest that the proposed method is effective in producing multi-layer micro cantilevers that display balanced residual stresses. The method provides a generic solution to the problem of mismatched initial stresses which universally exists in micro-electro-mechanical systems (MEMS) devices based on a BMC. Moreover, the method can be incorporated into a MEMS design automation package for efficient design of various multiple material layer devices from MEMS material library and developed deposition recipes.

  1. Compound surface-plasmon-polariton waves guided by a thin metal layer sandwiched between a homogeneous isotropic dielectric material and a structurally chiral material

    CERN Document Server

    Chiadini, Francesco; Scaglione, Antonio; Lakhtakia, Akhlesh

    2015-01-01

    Multiple compound surface plasmon-polariton (SPP) waves can be guided by a structure consisting of a sufficiently thick layer of metal sandwiched between a homogeneous isotropic dielectric (HID) material and a dielectric structurally chiral material (SCM). The compound SPP waves are strongly bound to both metal/dielectric interfaces when the thickness of the metal layer is comparable to the skin depth but just to one of the two interfaces when the thickness is much larger. The compound SPP waves differ in phase speed, attenuation rate, and field profile, even though all are excitable at the same frequency. Some compound SPP waves are not greatly affected by the choice of the direction of propagation in the transverse plane but others are, depending on metal thickness. For fixed metal thickness, the number of compound SPP waves depends on the relative permittivity of the HID material, which can be useful for sensing applications.

  2. Thermal stability of gold nanoparticles embedded within metal oxide frameworks fabricated by hybrid modifications onto sacrificial textile templates.

    Science.gov (United States)

    Padbury, Richard P; Halbur, Jonathan C; Krommenhoek, Peter J; Tracy, Joseph B; Jur, Jesse S

    2015-01-27

    The stability and spatial separation of nanoparticles (NP's) is essential for employing their advantageous nanoscale properties. This work demonstrates the entrapment of gold NP's embedded in a porous inorganic matrix. Initially, gold NP's are decorated on fibrous nylon-6, which is used as an inexpensive sacrificial template. This is followed by inorganic modification using a novel single exposure cycle vapor phase technique resulting in distributed NP's embedded within a hybrid organic-inorganic matrix. The processing is extended to the synthesis of porous nanoflakes after calcination of the modified nylon-6 yielding a porous metal oxide framework surrounding the disconnected NP's with a surface area of 250 m(2)/g. A unique feature of this work is the use of a transmission electron microscope (TEM) equipped with an in situ annealing sample holder. The apparatus affords the opportunity to explore the underlying nanoscopic stability of NP's embedded in these frameworks in a single step. TEM analysis indicates thermal stability up to 670 C and agglomeration characteristics thereafter. The vapor phase processes developed in this work will facilitate new complex NP/oxide materials useful for catalytic platforms. PMID:25557142

  3. Templating Sol-Gel Hematite Films with Sacrificial Copper Oxide: Enhancing Photoanode Performance with Nanostructure and Oxygen Vacancies.

    Science.gov (United States)

    Li, Yang; Guijarro, Nstor; Zhang, Xiaoli; Prvot, Mathieu S; Jeanbourquin, Xavier A; Sivula, Kevin; Chen, Hong; Li, Yongdan

    2015-08-12

    Nanostructuring hematite films is a critical step for enhancing photoelectrochemical performance by circumventing the intrinsic limitations on minority carrier transport. Herein, we present a novel sol-gel approach that affords nanostructured hematite films by including CuO as sacrificial templating agent. First, by annealing in air at 450 C a film comprising an intimate mixture of CuO and Fe2O3 nanoparticles is obtained. The subsequent treatment with NaCl and annealing at 700 C under Argon reveals a nanostructured highly crystalline hematite film devoid of copper. Photoelectrochemical investigations reveal that the incorporation of CuO as templating agent and the inert conditions employed during the annealing play a crucial role in the performance of the hematite electrodes. Mott-Schottky analysis shows a higher donor concentration when annealing in inert conditions, and even higher when combined with the NaCl treatment. These findings agree well with the presence of an oxygen-deficient shell on the material's surface evidenced by FT-IR and XPS measurements. Likewise, the incorporation of the CuO enhances the photocurrent obtained at 1.23 V from 0.55 to 0.8 mAcm(-2) because of an improved nanostructure. Optimized films demonstrate an incident photon-to-current efficiency (IPCE) of 52% at 380 nm when applying 1.23 V versus RHE, and a faradaic efficiency for water splitting close to unity. PMID:26186065

  4. Cyclododecane as support material for clean and facile transfer of large-area few-layer graphene

    Energy Technology Data Exchange (ETDEWEB)

    Capasso, A.; Leoni, E.; Dikonimos, T.; Buonocore, F.; Lisi, N. [ENEA, Materials Technology Unit, Surface Technology Laboratory, Casaccia Research Centre, Via Anguillarese 301, 00060 Rome (Italy); De Francesco, M. [ENEA, Technical Unit for Renewable Energies Sources, Casaccia Research Center, Via Anguillarese 301, 00060 Rome (Italy); Lancellotti, L.; Bobeico, E. [ENEA, Portici Research Centre, P.le E. Fermi 1, 80055 Portici (Italy); Sarto, M. S.; Tamburrano, A.; De Bellis, G. [Research Center on Nanotechnology Applied to Engineering of Sapienza (CNIS), SSNLab, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome (Italy)

    2014-09-15

    The transfer of chemical vapor deposited graphene is a crucial process, which can affect the quality of the transferred films and compromise their application in devices. Finding a robust and intrinsically clean material capable of easing the transfer of graphene without interfering with its properties remains a challenge. We here propose the use of an organic compound, cyclododecane, as a transfer material. This material can be easily spin coated on graphene and assist the transfer, leaving no residues and requiring no further removal processes. The effectiveness of this transfer method for few-layer graphene on a large area was evaluated and confirmed by microscopy, Raman spectroscopy, x-ray photoemission spectroscopy, and four-point probe measurements. Schottky-barrier solar cells with few-layer graphene were fabricated on silicon wafers by using the cyclododecane transfer method and outperformed reference cells made by standard methods.

  5. Tribological Investigations of Hard-Faced Layers and Base Materials of Forging Dies with Different Kinds of Lubricants Applied

    Directory of Open Access Journals (Sweden)

    V. Lazić

    2010-12-01

    Full Text Available This paper gives a procedure for choosing the right technology for reparative hard facing of damaged forging dies. Since they are subject to impact loads and cyclic temperature elevations, forging dies should be made of steel that is able to withstand great impact loads, maintain good mechanical properties at elevated temperatures and that is resistant to wear and thermal fatigue. For these reasons, forging dies are made of conditionally weldable alloy tool steels; however it makes hard facing of damaged tools even more difficult. In this paper, wear resistance of base materials, hard-faced layers and heat-affected zones are tribologically investigated when two different lubricants - pure synthetical oil LM 76 and LM 76 with 6% molybdenum disulfide (MoS2 are applied. Tribological investigations have shown that the wear resistance of the hard faced layers is considerably greater than the wear resistance of the base material. However, the base material has better properties concerning friction.

  6. Fabrication of functionally graded materials between P21 tool steel and Cu by using laser aided layered manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Jong Seol; Shin, Ki Hoon [Seoul Nat' l Univ., Seoul (Korea, Republic of)

    2013-01-15

    With the development of layered manufacturing, thermally conductive molds or molds embedding conformal cooling channels can be directly fabricated. Although P21 tool steel is widely used as a mold material because of its dimensional stability, it is not efficient for cooling molds owing to its low thermal conductivity. Hence, the use of functionally graded materials (FGMs) between P21 and Cu may circumvent a tradeoff between the strength and the heat transfer rate. As a preliminary study for the layered manufacturing of thermally conductive molds having FGM structures, one dimensional P21 Cu FGMs were fabricated by using laser aided direct metal tooling (DMT), and then, material properties such as the thermal conductivity and specific heat that are related to the heat transfer were measured and analyzed.

  7. Fabrication of functionally graded materials between P21 tool steel and Cu by using laser aided layered manufacturing

    International Nuclear Information System (INIS)

    With the development of layered manufacturing, thermally conductive molds or molds embedding conformal cooling channels can be directly fabricated. Although P21 tool steel is widely used as a mold material because of its dimensional stability, it is not efficient for cooling molds owing to its low thermal conductivity. Hence, the use of functionally graded materials (FGMs) between P21 and Cu may circumvent a tradeoff between the strength and the heat transfer rate. As a preliminary study for the layered manufacturing of thermally conductive molds having FGM structures, one dimensional P21 Cu FGMs were fabricated by using laser aided direct metal tooling (DMT), and then, material properties such as the thermal conductivity and specific heat that are related to the heat transfer were measured and analyzed

  8. Biofabrication of multi-material anatomically shaped tissue constructs

    International Nuclear Information System (INIS)

    Additive manufacturing in the field of regenerative medicine aims to fabricate organized tissue-equivalents. However, the control over shape and composition of biofabricated constructs is still a challenge and needs to be improved. The current research aims to improve shape, by converging a number of biocompatible, quality construction materials into a single three-dimensional fiber deposition process. To demonstrate this, several models of complex anatomically shaped constructs were fabricated by combined deposition of poly(vinyl alcohol), poly(?-caprolactone), gelatin methacrylamide/gellan gum and alginate hydrogel. Sacrificial components were co-deposited as temporary support for overhang geometries and were removed after fabrication by immersion in aqueous solutions. Embedding of chondrocytes in the gelatin methacrylamide/gellan component demonstrated that the fabrication and the sacrificing procedure did not affect cell viability. Further, it was shown that anatomically shaped constructs can be successfully fabricated, yielding advanced porous thermoplastic polymer scaffolds, layered porous hydrogel constructs, as well as reinforced cell-laden hydrogel structures. In conclusion, anatomically shaped tissue constructs of clinically relevant sizes can be generated when employing multiple building and sacrificial materials in a single biofabrication session. The current techniques offer improved control over both internal and external construct architecture underscoring its potential to generate customized implants for human tissue regeneration. (paper)

  9. Tube Formation in Nanoscale Materials

    Directory of Open Access Journals (Sweden)

    Yan Chenglin

    2008-01-01

    Full Text Available Abstract The formation of tubular nanostructures normally requires layered, anisotropic, or pseudo-layered crystal structures, while inorganic compounds typically do not possess such structures, inorganic nanotubes thus have been a hot topic in the past decade. In this article, we review recent research activities on nanotubes fabrication and focus on three novel synthetic strategies for generating nanotubes from inorganic materials that do not have a layered structure. Specifically, thermal oxidation method based on gassolid reaction to porous CuO nanotubes has been successfully established, semiconductor ZnS and Nb2O5nanotubes have been prepared by employing sacrificial template strategy based on liquidsolid reaction, and an in situ template method has been developed for the preparation of ZnO taper tubes through a chemical etching reaction. We have described the nanotube formation processes and illustrated the detailed key factors during their growth. The proposed mechanisms are presented for nanotube fabrication and the important pioneering studies are discussed on the rational design and fabrication of functional materials with tubular structures. It is the intention of this contribution to provide a brief account of these research activities.

  10. Layered-Layered-Spinel Cathode Materials Prepared by a High-Energy Ball-Milling Process for Lithium-ion Batteries.

    Science.gov (United States)

    Kim, Soo; Noh, Jae-Kyo; Aykol, Muratahan; Lu, Zhi; Kim, Haesik; Choi, Wonchang; Kim, Chunjoong; Chung, Kyung Yoon; Wolverton, Chris; Cho, Byung-Won

    2016-01-13

    In this work, we report the electrochemical properties of 0.5Li2MnO30.25LiNi0.5Co0.2Mn0.3O20.25LiNi0.5Mn1.5O4 and 0.333Li2MnO30.333LiNi0.5Co0.2Mn0.3O20.333LiNi0.5Mn1.5O4 layered-layered-spinel (L*LS) cathode materials prepared by a high-energy ball-milling process. Our L*LS cathode materials can deliver a large and stable capacity of ?200 mAh?g(-1) at high voltages up to 4.9 V, and do not show the anomalous capacity increase upon cycling observed in previously reported three-component cathode materials synthesized with different routes. Furthermore, we have performed synchrotron-based in situ X-ray diffraction measurements and found that there are no significant structural distortions during charge/discharge runs. Lastly, we carry out (opt-type) van der Waals-corrected density functional theory (DFT) calculations to explain the enhanced cycle characteristics and reduced phase transformations in our ball-milled L*LS cathode materials. Our simple synthesis method brings a new perspective on the use of the high-power L*LS cathodes in practical devices. PMID:26645115

  11. Novel hetero-layered materials with tunable direct band gaps by sandwiching different metal disulfides and diselenides

    Science.gov (United States)

    Terrones, Humberto; Lpez-Uras, Florentino; Terrones, Mauricio

    2013-01-01

    Although bulk hexagonal phases of layered semiconducting transition metal dichalcogenides (STMD) such as MoS2, WS2, WSe2 and MoSe2 exhibit indirect band gaps, a mono-layer of STMD possesses a direct band gap which could be used in the construction of novel optoelectronic devices, catalysts, sensors and valleytronic components. Unfortunately, the direct band gap only occurs for mono-layered STMD. We have found, using first principles calculations, that by alternating individual layers of different STMD (MoS2, WS2, WSe2 and MoSe2) with particular stackings, it is possible to generate direct band gap bi-layers ranging from 0.79 eV to 1.157?eV. Interestingly, in this direct band gap, electrons and holes are physically separated and localized in different layers. We foresee that the alternation of different STMD would result in the fabrication of materials with unprecedented optical and physico-chemical properties that would need further experimental and theoretical investigations. PMID:23528957

  12. Effect of Soft Material Hardness and Hard Material Surface Morphology on Friction and Transfer Layer Formation; Dry Condition

    Directory of Open Access Journals (Sweden)

    Mr.M Basavaraju

    2013-09-01

    Full Text Available The morphological features of the surface in both micro and macro levels are important factors governing the tribological behavior of the contacting surfaces. Surface hardness is also an important factor which governs the friction and wear behaviors of the contacting surfaces. Surface morphology of a tool is an important factor as it primarily controls the tribological behavior at the interface which in turn controls the surface finish of products. In the present investigation a pin-on-plate sliding tester was used to identify the effect of surface morphology and hardness on co-efficient of friction and transfer layer which characterizes the tribological behavior. The morphology of mild steel (EN8 plate surfaces were modified by employing three different surface modification methods like grinding (silicon carbide wheel polishing, shot blasting and electric discharge machining methods. Surface roughness parameters which characterize the morphology of the steel plates were measured using a three dimensional optical profilometer. Role of hardness is studied by employing lead, copper and Aluminum (Al6082 pins which were slid against steel plates. Experiments were conducted for plate inclination angles of 1, 1.5,2 and 2.5 degrees. Normal load was varied from 1 to 150N during the tests. Experiments were conducted under dry condition in ambient environment. Scanning electron microscope was used to study the formation of transfer layer on plate and pin surfaces. It was observed that the co-efficient of friction and transfer layer formation were found to depend on the surface morphology of the harder surface. The quantum of transfer layer formation on the surfaces is found to increase with increase in surface roughness

  13. Effect of Soft Material Hardness and Hard Material Surface Morphology on Friction and Transfer Layer Formation; Lubricated Condition

    Directory of Open Access Journals (Sweden)

    Dr.S Ranganatha

    2013-09-01

    Full Text Available Hot and cold forming of metals is carried out in industry for manufacturing engineering components. Such manufacturing processes employ dies, whose surface condition is one of the factors which characterize the surface finish of engineering components. The surface finish of engineering components is largely influenced by the tribological phenomenon at die and components interface. Lubrication, morphology and hardness of die surface are found to control surface finish of the products. In the present investigation a pin-on-plate sliding tester was used to identify the effect of surface morphology, lubrication and hardness on co-efficient of friction and transfer layer which characterizes the tribological behaviour. The morphology of mild steel (EN8 plate surfaces were modified by employing three different surface modification methods like grinding (silicon carbide wheel polishing, shot blasting and electric discharge machining methods. Surface roughness parameters which characterize the morphology of the steel plates were measured using a three dimensional optical profilometer. Role of hardness is studied by employing lead, copper and Aluminum (Al6082 pins which were slid against steel plates. Experiments were conducted for plate inclination angles of 1, 1.5,2 and 2.5 degrees. Normal load was varied from 1 to 150N during the tests. Experiments were conducted under lubricated condition in ambient environment. Scanning electron microscope was used to study the formation of transfer layer on plate and pin surfaces. It was observed that the co-efficient of friction and transfer layer formation were found to depend on the surface morphology of the harder surface under lubricated condition. The quantum of transfer layer formation on the surfaces is found to increase with increase in surface roughness.

  14. A study of Al-Zn-Sn alloy sacrificial anode cathodic protection requirements for structure used in seawater

    International Nuclear Information System (INIS)

    Full text: The study will be focused on the alloying of Aluminum alloy sacrificial anode. The work will explore, evaluate and assess the effectiveness of Al-Zn-Sn alloy sacrificial anode tested in tropical seawater. This study is directed toward the development of new and more comprehensive data that will provide a technical basis for improved, more cost - effective guidelines for prediction, verification and optimization of cathodic protection requirements for structures used in tropical seawater. Furthermore, this study will also evaluate the potential and benefits of laboratory research upon marine corrosion without needed to be in the actual marine environment. The influence of alloy composition on the electrochemical properties of this Al-Zn-Sn will be determined by various tasks of testing which fully conducted in the laboratory. SEM and EDAX analysis will be employed in order to characterize surface structure of Al-Zn-Sn alloy. The corrosion measurement analyzer will be used by means to identify the electrochemical properties such as potential, corrosion rate and passivation of Al-Zn-Sn sacrificial anode when immersed in seawater. The relationship between morphological structure and electrochemical results will be examined. The data obtained will be used to evaluate the performance of Al-Zn-Sn alloy as a sacrificial anode cathodic protection for structure used in tropical seawater. Further verification will be made to testify that the Al-Zn-Sn alloy meets the quality requirements to be used as a sacrificial anode in tropical seawater. (author)

  15. Long-term performance of different aluminum alloy designs as sacrificial anodes for rebars

    International Nuclear Information System (INIS)

    This paper presents the performance of various cathodic-protection designs using Aluminum alloys to protect prestressed piles. The results obtained with different system designs (bracelete type-Al/Zn/In alloy, thermo sprayed aluminum (3-year evaluation) and conventional Al/Zn/In anodes in an epoxy-painted steel bracelet (12-year evaluation), indicated that all of these systems may be used as sacrificial anodes for pile protection. However, the thermo sprayed aluminum type can not be used in prestressed concrete piles because the very negative potentials (4) they supply to the reinforcement could lead to hydrogen embrittlement. (Author) 16 refs

  16. Gas purification by the plasma-oxidation of a rotating sacrificial electrode

    Science.gov (United States)

    Dahle, S.; Hirschberg, J.; Vil, W.; Maus-Friedrichs, W.

    2015-06-01

    A novel approach for the purification of inert gases by means of a dielectric barrier discharge (DBD) plasma has been demonstrated for argon and nitrogen. A rotating sacrificial electrode has been employed together with an electrode cleaning system to remove passivating product films during the plasma processing and thus enhance capacity and reaction rates. The purification of nitrogen using this approach was shown to be quite successful. The conditioning of technical argon yielded rotational temperatures well beyond 150?C, thus being unable to remove the water content effectively.

  17. Encapsulation of sacrificial silicon containing particles for SH oxide ceramics via a boehmite precursor route:

    OpenAIRE

    Carabat, A.L.; Zwaag, S. van der; Sloof, W. G.

    2013-01-01

    Easy crack propagation in oxide ceramic coatings limits their application in high temperature environment (e.g. such as engines and gas turbine components) [1]. In order to overcome this problem, incorporation of sacrificial particles into an oxide ceramic coating may be a viable option. Particles of silicon compounds, such as: Si3N4, SiC, MoSi2, TaSi2 and WSi2 are attractive due to their unique features of producing a reaction product (i.e. SiO2) which fills the crack and bonds well to the s...

  18. Ciprofloxacin-intercalated Zinc Layered Hydroxides Hybrid Material: Synthesis and in Vitro Release Profiles of an Antibiotic Compound

    International Nuclear Information System (INIS)

    The intriguing anion exchange properties of layered hydroxides salts, combined with its high layer charge density have provided strong motivations for the potential use of the inorganic layered host material in drug delivery applications. Ciprofloxacin (CFX), a wide spectrum antibiotic has been anion exchanged with nitrate of zinc hydroxide nitrate (ZHN), which belongs to the LHS family, resulted in the expansion of the basal spacing from 9.92 Amstrom of ZHN to 21.5 Angstrom of ZCFX, the obtained hybrid material. Other characterizations, such as Fourier transform infra red spectroscopy (FTIR), CHNS analysis and TGA/ DTG have further corroborated this finding. Electron microscopy study reveals the plate-like structure of the nano hybrid material. The in vitro release of CFX was performed in phosphate saline buffer at pH 7.4 and it behaves in a slow and sustained release profile over a period of 72 hours. This study suggests that ZHN, which demonstrates a controlled release behavior, could be a potential host material in the drug delivery applications. (author)

  19. Efficiency of a Multi-Soil-Layering System on Wastewater Treatment Using Environment-Friendly Filter Materials

    Directory of Open Access Journals (Sweden)

    Chia-Chun Ho

    2015-03-01

    Full Text Available The multi-soil-layering (MSL system primarily comprises two parts, specifically, the soil mixture layer (SML and the permeable layer (PL. In Japan, zeolite is typically used as the permeable layer material. In the present study, zeolite was substituted with comparatively cheaper and more environmentally friendly materials, such as expanded clay aggregates, oyster shells, and already-used granular activated carbon collected from water purification plants. A series of indoor tests indicated that the suspended solid (SS removal efficiency of granular activated carbon was between 76.2% and 94.6%; zeolite and expanded clay aggregates achieved similar efficiencies that were between 53.7% and 87.4%, and oyster shells presented the lowest efficiency that was between 29.8% and 61.8%. Further results show that the oyster shell system required an increase of wastewater retention time by 2 to 4 times that of the zeolite system to maintain similar chemical oxygen demand (COD removal efficiency. Among the four MSL samples, the zeolite system and granular activated carbon system demonstrated a stable NH3-N removal performance at 92.3%99.8%. The expanded clay aggregate system present lower removal performance because of its low adsorption capacity and excessively large pores, causing NO3?-N to be leached away under high hydraulic loading rate conditions. The total phosphorous (TP removal efficiency of the MSL systems demonstrated no direct correlation with the permeable layer material. Therefore, all MSL samples achieved a TP efficiency of between 92.1% and 99.2%.

  20. Efficiency of a multi-soil-layering system on wastewater treatment using environment-friendly filter materials.

    Science.gov (United States)

    Ho, Chia-Chun; Wang, Pei-Hao

    2015-03-01

    The multi-soil-layering (MSL) system primarily comprises two parts, specifically, the soil mixture layer (SML) and the permeable layer (PL). In Japan, zeolite is typically used as the permeable layer material. In the present study, zeolite was substituted with comparatively cheaper and more environmentally friendly materials, such as expanded clay aggregates, oyster shells, and already-used granular activated carbon collected from water purification plants. A series of indoor tests indicated that the suspended solid (SS) removal efficiency of granular activated carbon was between 76.2% and 94.6%; zeolite and expanded clay aggregates achieved similar efficiencies that were between 53.7% and 87.4%, and oyster shells presented the lowest efficiency that was between 29.8% and 61.8%. Further results show that the oyster shell system required an increase of wastewater retention time by 2 to 4 times that of the zeolite system to maintain similar chemical oxygen demand (COD) removal efficiency. Among the four MSL samples, the zeolite system and granular activated carbon system demonstrated a stable NH3-N removal performance at 92.3%-99.8%. The expanded clay aggregate system present lower removal performance because of its low adsorption capacity and excessively large pores, causing NO3--N to be leached away under high hydraulic loading rate conditions. The total phosphorous (TP) removal efficiency of the MSL systems demonstrated no direct correlation with the permeable layer material. Therefore, all MSL samples achieved a TP efficiency of between 92.1% and 99.2%. PMID:25809517

  1. Molecular plating of thin lanthanide layers with improved material properties for nuclear applications

    Energy Technology Data Exchange (ETDEWEB)

    Vascon, Alessio

    2013-06-26

    This work describes experiments to gain an improved understanding of the processes associated with the electrochemical production of thin lanthanide layers for nuclear science investigations, i.e., nuclear targets. Nd, Sm, and Gd layers were prepared by means of the so-called molecular plating (MP) technique, where electrodeposition from an organic medium is usually performed in the constant current mode using two-electrode cells. The obtained results allowed the identification of optimized production conditions, which led to a significantly improved layer quality. Constant current density MP is a mass-transport controlled process. The applied current is maintained constant by constant fluxes of electroactive species towards the cathode - where the layer is grown - and the anode. The investigations showed the cell potentials of the electrodeposition systems to be always dominated by the ohmic drop produced by the resistance of the solutions used for the studies. This allowed to derive an expression relating cell potential with concentration of the electroactive species. This expression is able to explain the trends recorded with different electrolyte concentrations and it serves as a basis to get towards a full understanding of the reasons leading to the characteristic minima observed in the evolution of the cell potential curves with time. The minima were found to correspond to an almost complete depletion of the Nd ions obtained by dissolution of the model salt used for the investigations. Nd was confirmed to be deposited at the cathode as derivatives of Nd{sup 3+} - possibly as carboxylate, oxide or hydroxide. This fact was interpreted on the basis of the highly negative values of the standard redox potentials typical for lanthanide cations. Among the different electroactive species present in the complex MP solutions, the Nd{sup 3+} ions were found to contribute to less than 20% to the total current. Because of electrolysis, also the mixed solvent contributed to the applied constant current as an electroactive species. The presence of electrolyzed solvent was confirmed by the analysis of the produced deposits, which were always covered by both chemisorbed and physisorbed solvent molecules. Target characterizations showed the surfaces of the layers to present severe cracks, which were found to form during the drying time after completion of the MP. Different drying environments, i.e., air or Ar, did not affect the deposits. The drying-related nature of cracking and the solvent composition of the produced layers suggested to perform constant current density MPs using solvents with significantly different physical properties, most notably the boiling point. N,N-dimethylformamide (DMF), i.e., the highest boiling point solvent, proved to be very effective for the production of crack-free surfaces. DMF, in combination with the use of very smooth deposition substrates, allowed the growth of smooth, defectless layers, which likely underwent smaller stress during drying than the deposits produced by using rougher substrates and more volatile solvents. The roughness of the deposition substrate and the solvent used for the platings proved then to be core factors for the preparation of high quality layers. MP thus showed to be very effective for the production of uniform and homogeneous targets with excellent yield. Tests of the performance of layers produced by MP as ?-particle sources were also carried out. {sup 147}Sm was used as model isotope for the ? spectroscopy investigations. Both peak resolution and the fraction of ? particles reaching the detector were found to be influenced by source effects. These effects were categorized according to different ''layer variables'', i.e., variables influencing the ? spectra by means of ''layer effects'', and were found to be promoted by the plating solvent and the roughness of the deposition substrate used to perform the MPs. These parameters likely affected thickness, morphology, and growth mode of the layers. The layer variables proved to

  2. Structural characterization of thin layered materials using x-ray standing wave enhanced elastic and inelastic scattering measurements

    International Nuclear Information System (INIS)

    By measuring the intensities of the x-ray standing wave induced elastic and inelastic x-ray scattering from thin multilayer structures, we show that structural characterizations of the high and low z (atomic number) material layers can be performed independently. The method has been tested by analyzing the structural properties of an Nb/C/Nb trilayer and an Mo/Si periodic multilayer structure. The results of the x-ray scattering measurements have been compared with those obtained using x-ray reflectivity and conventional x-ray standing wave fluorescence techniques. It has been demonstrated that the present approach is especially suitable for studying multilayer structures comprising low atomic number layers, as it eliminates the requirement of a fluorescence signal, which is very weak in the case of low z materials.

  3. Flaw investigation in a multi-layered, multi-material composite: Using air-coupled ultrasonic resonance imaging

    Science.gov (United States)

    Livings, R. A.; Dayal, V.; Barnard, D. J.; Hsu, D. K.

    2012-05-01

    Ceramic tiles are the main ingredient of a multi-material, multi-layered composite being considered for the modernization of tank armors. The high stiffness, low attenuation, and precise dimensions of these uniform tiles make them remarkable resonators when driven to vibrate. Defects in the tile, during manufacture or after usage, are expected to change the resonance frequencies and resonance images of the tile. The comparison of the resonance frequencies and resonance images of a pristine tile/lay-up to a defective tile/lay-up will thus be a quantitative damage metric. By examining the vibrational behavior of these tiles and the composite lay-up with Finite Element Modeling and analytical plate vibration equations, the development of a new Nondestructive Evaluation technique is possible. This study examines the development of the Air-Coupled Ultrasonic Resonance Imaging technique as applied to a hexagonal ceramic tile and a multi-material, multi-layered composite.

  4. Role of atomic layer deposited aluminum oxide as oxidation barrier for silicon based materials

    Energy Technology Data Exchange (ETDEWEB)

    Fiorentino, Giuseppe, E-mail: g.fiorentino@tudelft.nl; Morana, Bruno [Department of Microelectronic, Delft University of Technology, Feldmannweg 17, 2628 CT Delft (Netherlands); Forte, Salvatore [Department of Electronic, University of Naples Federico II, Piazzale Tecchio, 80125 Napoli (Italy); Sarro, Pasqualina Maria [Department of Microelectronic, Delft University of Technology, Feldmannweg 17, 2628 CT, Delft (Netherlands)

    2015-01-15

    In this paper, the authors study the protective effect against oxidation of a thin layer of atomic layer deposited (ALD) aluminum oxide (Al{sub 2}O{sub 3}). Nitrogen doped silicon carbide (poly-SiC:N) based microheaters coated with ALD Al{sub 2}O{sub 3} are used as test structure to investigate the barrier effect of the alumina layers to oxygen and water vapor at very high temperature (up to 1000?C). Different device sets have been fabricated changing the doping levels, to evaluate possible interaction between the dopants and the alumina layer. The as-deposited alumina layer morphology has been evaluated by means of AFM analysis and compared to an annealed sample (8 h at 1000?C) to estimate the change in the grain structure and the film density. The coated microheaters are subjected to very long oxidation time in dry and wet environment (up to 8 h at 900 and 1000?C). By evaluating the electrical resistance variation between uncoated reference devices and the ALD coated devices, the oxide growth on the SiC is estimated. The results show that the ALD alumina coating completely prevents the oxidation of the SiC up to 900?C in wet environment, while an oxide thickness reduction of 50% is observed at 1000?C compared to uncoated devices.

  5. Role of atomic layer deposited aluminum oxide as oxidation barrier for silicon based materials

    International Nuclear Information System (INIS)

    In this paper, the authors study the protective effect against oxidation of a thin layer of atomic layer deposited (ALD) aluminum oxide (Al2O3). Nitrogen doped silicon carbide (poly-SiC:N) based microheaters coated with ALD Al2O3 are used as test structure to investigate the barrier effect of the alumina layers to oxygen and water vapor at very high temperature (up to 1000?C). Different device sets have been fabricated changing the doping levels, to evaluate possible interaction between the dopants and the alumina layer. The as-deposited alumina layer morphology has been evaluated by means of AFM analysis and compared to an annealed sample (8 h at 1000?C) to estimate the change in the grain structure and the film density. The coated microheaters are subjected to very long oxidation time in dry and wet environment (up to 8 h at 900 and 1000?C). By evaluating the electrical resistance variation between uncoated reference devices and the ALD coated devices, the oxide growth on the SiC is estimated. The results show that the ALD alumina coating completely prevents the oxidation of the SiC up to 900?C in wet environment, while an oxide thickness reduction of 50% is observed at 1000?C compared to uncoated devices

  6. Poromechanical modelling of hygric shrinkage and crystallization swelling in layered porous materials

    OpenAIRE

    Derluyn, Hannelore; Poupeleer, Anne-Sverine; Moonen, Peter; Carmeliet, Jan

    2007-01-01

    Salt ions may penetrate into building materials due to diffusive and convective transport processes through cracks or uncracked material parts. When drying occurs, the salts present in the material may crystallize first in coarse pores and subsequently in finer pores causing increasing expansive forces on the solid material. This process may finally lead to damage and cracking. Understanding the damage mechanism due to salt crystallization will contribute to a better knowledge on how to preve...

  7. Adhesive and stress-strain properties of the polymeric layered materials reinforced by the knitted net

    International Nuclear Information System (INIS)

    It is known that the textile materials (woven fabric and mesh) used for reinforcing of various polymer films and coatings. This paper discusses reinforcement of thermoplastic polymers based on PE (polyethylene) and PVC (polyvinyl Chloride) with a knitted mesh weave loin. According by the research identified adhesion, strength and deformation properties of new polymer laminates. The production of such materials has been discussed in detail and performance of resultant composites material is analyzed and compared with other materials. (author)

  8. Wrinkling micropatterns regulated by a hard skin layer with a periodic stiffness distribution on a soft material

    Science.gov (United States)

    Wang, Jiawen; Li, Bo; Cao, Yan-Ping; Feng, Xi-Qiao; Gao, Huajian

    2016-01-01

    A wrinkling-based method is proposed to create various surface micropatterns regulated by a hardened skin layer with a periodic stiffness distribution on a soft material. It is shown that the surface patterns generated by this technique are controlled by three fundamental surface deformation modes that involve sinusoidal wrinkling, Euler buckling, and rigid rotation of the skin. Systematic experiments and a phase diagram validate the efficacy and robustness of the proposed method.

  9. Dual catalysis with magnetic chitosan: direct synthesis of cyclic carbonates from olefins with carbon dioxide using isobutyraldehyde as the sacrificial reductant.

    Science.gov (United States)

    Kumar, Subodh; Singhal, Nikita; Singh, Raj K; Gupta, Piyush; Singh, Raghuvir; Jain, Suman L

    2015-07-14

    Chitosan coated magnetic nanoparticles were synthesized and used as a support for the immobilization of the cobalt(II) acetylacetonate complex [Co(acac)2] and quaternary triphenylphosphonium bromide [P(+)Ph3Br(-)] targeting -NH2 and -OH moieties located on the surface of chitosan. The synthesized material was used as a catalyst for one pot direct synthesis of cyclic carbonates from olefins via an oxidative carboxylation approach with carbon dioxide using isobutyraldehyde as the sacrificial reductant and molecular oxygen as the oxidant. After the reaction, the catalyst was recovered by applying an external magnet and reused for several runs without significant loss in catalytic activity and no leaching was observed during this course. PMID:26055991

  10. Antibacterial activity of microstructured Ag/Au sacrificial anode thin films.

    Science.gov (United States)

    Kller, Manfred; Sengstock, Christina; Motemani, Yahya; Khare, Chinmay; Buenconsejo, Pio J S; Geukes, Jonathan; Schildhauer, Thomas A; Ludwig, Alfred

    2015-01-01

    Ten different Ag dot arrays (16 to 625 microstructured dots per square mm) were fabricated on a continuous Au thin film and for comparison also on Ti film by sputter deposition and photolithographic patterning. To analyze the antibacterial activity of these microstructured films Escherichia coli and Staphylococcus aureus were placed onto the array surfaces and cultivated overnight. To analyze the viability of planktonic as well as surface adherent bacteria, the applied bacterial fluid was subsequently aspirated, plated on blood agar plates and adherent bacteria were detected by fluorescence microscopy. A particular antibacterial effect towards both bacterial strains was induced by Ag dot arrays on fabricated Au thin film (sacrificial anode system for Ag), due to the release of Ag ions from dissolution of Ag dots in contrast to Ag dot arrays fabricated on the Ti thin films (non-sacrificial anode system for Ag) which remained intact to the original dot shape. The required number of Ag dots on gold film to achieve complete bactericidal effects for both bacterial strains was seven times lower than that observed with Ag dot arrays on Ti film. PMID:25491988

  11. Fabrication of scalable and structured tissue engineering scaffolds using water dissolvable sacrificial 3D printed moulds

    DEFF Research Database (Denmark)

    Mohanty, Soumyaranjan; Larsen, Layla Bashir

    2015-01-01

    One of the major challenges in producing large scale engineered tissue is the lack of ability to create large highly perfused scaffolds in which cells can grow at a high cell density and viability. Here, we explore 3D printed polyvinyl alcohol (PVA) as a sacrificial mould in a polymer casting process. The PVA mould network defines the channels and is dissolved after curing the polymer casted around it. The printing parameters determined the PVA filament density in the sacrificial structure and this density resulted in different stiffness of the corresponding elastomer replica. It was possible to achieve 80% porosity corresponding to about 150 cm2/cm3 surface to volume ratio. The process is easily scalable as demonstrated by fabricating a 75 cm3 scaffold with about 16,000 interconnected channels (about 1 m2 surface area) and with a channel to channel distance of only 78 ?m. To our knowledge this is the largest scaffold ever to be produced with such small feature sizes and with so many structuredchannels. The fabricated scaffoldswere applied for in-vitro culturing of hepatocytes over a 12-day culture period. Smaller scaffolds (6 4mm) were tested for cell culturing and could support homogeneous cell growth throughoutthe scaffold. Presumably, the diffusion of oxygen and nutrient throughout the channel network is rapid enough to support cell growth. In conclusion, the described process is scalable, compatible with cell culture, rapid, and inexpensive.

  12. Fabrication of scalable and structured tissue engineering scaffolds using water dissolvable sacrificial 3D printed moulds.

    Science.gov (United States)

    Mohanty, Soumyaranjan; Larsen, Layla Bashir; Trifol, Jon; Szabo, Peter; Burri, Harsha Vardhan Reddy; Canali, Chiara; Dufva, Marin; Emnus, Jenny; Wolff, Anders

    2015-10-01

    One of the major challenges in producing large scale engineered tissue is the lack of ability to create large highly perfused scaffolds in which cells can grow at a high cell density and viability. Here, we explore 3D printed polyvinyl alcohol (PVA) as a sacrificial mould in a polymer casting process. The PVA mould network defines the channels and is dissolved after curing the polymer casted around it. The printing parameters determined the PVA filament density in the sacrificial structure and this density resulted in different stiffness of the corresponding elastomer replica. It was possible to achieve 80% porosity corresponding to about 150 cm(2)/cm(3) surface to volume ratio. The process is easily scalable as demonstrated by fabricating a 75 cm(3) scaffold with about 16,000 interconnected channels (about 1m(2) surface area) and with a channel to channel distance of only 78 ?m. To our knowledge this is the largest scaffold ever to be produced with such small feature sizes and with so many structured channels. The fabricated scaffolds were applied for in-vitro culturing of hepatocytes over a 12-day culture period. Smaller scaffolds (64 mm) were tested for cell culturing and could support homogeneous cell growth throughout the scaffold. Presumably, the diffusion of oxygen and nutrient throughout the channel network is rapid enough to support cell growth. In conclusion, the described process is scalable, compatible with cell culture, rapid, and inexpensive. PMID:26117791

  13. From a Philosophical point of view, can the Budism Be An Anti-Sacrificial Science?

    Directory of Open Access Journals (Sweden)

    Francisco Felizol Marques

    2014-04-01

    Full Text Available Both on Buddhist tradition and Ren Girards thought ignorance and desire are on the basis of suffering and violence. The Buddhist tradition puts/takes ignorance, that nothing exists in and by itself, avydia as the cause of all sufferings because it generates a chain of desire / aversion that leads us to an imprisonment where we move from desiring an object to another. Girards perspective founds violences origin on the ignorance of our mimetic desire. The subject ignores that, far from being free, autonomous and differentiated, as the "romantic lie" prays, he only desires and wants by imitating a model. Neither the subject nor the object, which the subject freely thinks to desire, exist free for themselves. While this model prevails, he will react more and more violently to the claims of the subject; and even if the subject overtakes its model, he will greedily seek another and another model, always doomed to deception. If we add to this the proximity of the two anti-sacrificial perspectives, displayed on the descriptive closeness of the samsaras wheel and the circular and sacrificial time of a pagan society, we find between Girard and the buddhist tradition enough common points for their mutual understanding.

  14. Magnesium-Based Sacrificial Anode Cathodic Protection Coatings (Mg-Rich Primers for Aluminum Alloys

    Directory of Open Access Journals (Sweden)

    Michael D. Blanton

    2012-09-01

    Full Text Available Magnesium is electrochemically the most active metal employed in common structural alloys of iron and aluminum. Mg is widely used as a sacrificial anode to provide cathodic protection of underground and undersea metallic structures, ships, submarines, bridges, decks, aircraft and ground transportation systems. Following the same principle of utilizing Mg characteristics in engineering advantages in a decade-long successful R&D effort, Mg powder is now employed in organic coatings (termed as Mg-rich primers as a sacrificial anode pigment to protect aerospace grade aluminum alloys against corrosion. Mg-rich primers have performed very well on aluminum alloys when compared against the current chromate standard, but the carcinogenic chromate-based coatings/pretreatments are being widely used by the Department of Defense (DoD to protect its infrastructure and fleets against corrosion damage. Factors such as reactivity of Mg particles in the coating matrix during exposure to aggressive corrosion environments, interaction of atmospheric gases with Mg particles and the impact of Mg dissolution, increases in pH and hydrogen gas liberation at coating-metal interface, and primer adhesion need to be considered for further development of Mg-rich primer technology.

  15. Monitoring the Startup of a Sacrificial Concrete Sewer for Odor Control

    DEFF Research Database (Denmark)

    Nielsen, Asbjrn Haaning; Vollertsen, Jes

    2014-01-01

    The use of a sacrificial concrete sewer for controlling sulphide-related odour downstream of a pressure sewer was investigated in this study. The investigated sewer is located in a rural catchment and is intended to alleviate odour problems downstream of a small diameter pressure sewer with extended retention time. For the purpose of the study, a 50-m long sacrificial concrete gravity sewer was constructed using a high alkalinity concrete pipe. The monitoring campaign reported in this paper covers the first 9 months of operation. The results clearly demonstrate the ability of the system to reduce hydrogen sulphide gas (H2S (g)) concentrations in the sewer headspace. After being in operation for approximately half a year, the system was able to maintain average H2S (g) levels of less than 1 ppmv at the downstream end, which is the first place air can escape. The daily maximum H2S (g) levels (95 percentile) were reduced from several hundred ppmv in the discharge manhole to approximately 10 ppmv at the downstream end. Thus, the odour potential has been significantly reduced. A visual inspection of the system revealed that even after 9 months of operation not all of the concrete surfaces were corroding. The removal efficiency is therefore expected to increase further.

  16. Ab initio and thermodynamic modelling of alloying effects on activity of sacrificial aluminium anodes

    International Nuclear Information System (INIS)

    Research highlights: ? Effect of alloying on the corrosion activity of sacrificial Al anodes. ? Sn in solid solution form is a key alloying element for activation of Al anodes. ? Ternary additions that increase Sn solubility decrease the potential of Al alloys. ? Elements bigger than Al expand the Al lattice and allow more Sn to dissolve in Al. ? Large ternary dopants can reduce Sn's solubility in Al if they form compounds with Sn. - Abstract: This work summarizes the experimental literature to date on Al-alloy sacrificial anodes and shows that the presence of Sn as an alloying element in solid solution form consistently debases the alloy corrosion potential. This study then assesses the lattice expander theory, which states that lattice-expanding dopants can be used to increase Sn solubility in Al and thereby reduce passivation. The thermodynamic effects on Sn solubility of lattice expanders (Ga, Mg, Zr, In and Bi) are predicted with ab-initio methods. Our results support lattice expander theory although we demonstrate that Sn solubility can decrease by alloying with even large dopants if they form compounds with Sn.

  17. Heat transfer and material flow during laser assisted multi-layer additive manufacturing

    International Nuclear Information System (INIS)

    A three-dimensional, transient, heat transfer, and fluid flow model is developed for the laser assisted multilayer additive manufacturing process with coaxially fed austenitic stainless steel powder. Heat transfer between the laser beam and the powder particles is considered both during their flight between the nozzle and the growth surface and after they deposit on the surface. The geometry of the build layer obtained from independent experiments is compared with that obtained from the model. The spatial variation of melt geometry, cooling rate, and peak temperatures is examined in various layers. The computed cooling rates and solidification parameters are used to estimate the cell spacings and hardness in various layers of the structure. Good agreement is achieved between the computed geometry, cell spacings, and hardness with the corresponding independent experimental results.

  18. Influence of the type of ceramic moulding materials on the top layer of titanium precision castings

    Directory of Open Access Journals (Sweden)

    Myszka D.

    2007-01-01

    Full Text Available The article presents the results of the research which was executed to describe the conditions specific of the formation of surface of certain micro-geometry and of the upper layers on precision titanium castings for medical industry. On the ready precision castings some tests were carried out to obtain the surface micro-geometry satisfying the requirements of implants to be used in human organism. The surfaces with specific spherical macro-unevenness were formed as well as plane surfaces of 2 6 ?m roughness. With the help of the light and electron microscopy, the possibility of formation of upper layers directly through an interaction of liquid titanium or Ti6Al4V alloy with the first layer of ceramic mould made from the ceramic mixtures based on Ekosil binder and molochite or zirconia has been confirmed.

  19. A WOOD REPLACEMENT MATERIAL OF SANDWICH STRUCTURE USING COIR FIBER MATS AND FIBERGLASS FABRICS AS CORE LAYER

    Directory of Open Access Journals (Sweden)

    Jia Yao,

    2011-12-01

    Full Text Available The tensile strength and bending strength of natural coir fiber are lower than many other natural fibers. Therefore, coir fiber is unsuitable for many fiber reinforcement applications. This study exploits the better shock resistance and toughness of coir fiber, which suggest that coir fiber can be used as a type of replacement material in plywood. Fast-growing poplar was chosen as the surface material, and coir fiber was selected as the core layer material for their buffering ability and toughness, and fiberglass fabrics were added in the core layer as strengthening components. The optimization of this plywood structure was carried out with an orthogonal experiment and the intuitive analysis method. The mechanical performance of some samples even exceeded that of natural wood. Through analysis of test results and scanning electron microscope (SEM observations, the buffering and toughening mechanisms of the coir fiber mats were revealed. This new material can be used to replace wood in plywood and in the transportation industry as a packaging material and as platform floors for freight vehicles.

  20. Production of Quasicomposite Surface Layer of a Metal Material by Shock Wave Strain Hardening

    Directory of Open Access Journals (Sweden)

    A.V.Kirichek

    2014-07-01

    Full Text Available Quite often in order to improve the performance of a product it is necessary to form a strengthened structure that will be extremely hard and have good plasticity at the same time. One way to meet this challenge is to apply shock wave mechanical hardening to produce micro- or nanocrystalline heterogeneous structures in homogeneous metals or alloys. A peculiar feature of such structure is its layer-by-layer formation with smooth transition between hard and plastic areas, which improves the performance of the strengthened item significantly

  1. Sacrificial structures for deep reactive ion etching of high-aspect ratio kinoform silicon x-ray lenses

    DEFF Research Database (Denmark)

    Sthr, Frederik; Michael-Lindhard, Jonas; Hbner, Jrg; Jensen, Flemming; Simons, Hugh; Jakobsen, Anders Clemen; Poulsen, Henning Friis; Hansen, Ole

    2015-01-01

    investigated how sacrificial structures in the form of guarding walls and pillars may be utilized to facilitate accurate control of the etch profile. Unlike other sacrificial structuring approaches, no silicon-on-insulator substrates or multiple lithography steps are required. In addition, the safe removal of......This article describes the realization of complex high-aspect ratio silicon structures with feature dimensions from 100 lm to 100nm by deep reactive ion etching using the Bosch process. As the exact shape of the sidewall profiles can be crucial for the proper functioning of a device, the authors...

  2. [Ru(bpy)3]2+-doped silica nanoparticles within layer-by-layer biomolecular coatings and their application as a biocompatible electrochemiluminescent tag material.

    Science.gov (United States)

    Wei, Hui; Liu, Jifeng; Zhou, Lingling; Li, Jing; Jiang, Xiue; Kang, Jianzhen; Yang, Xiurong; Dong, Shaojun; Wang, Erkang

    2008-01-01

    [Ru(bpy)3]2+-doped silica (RuSi) nanoparticles were synthesized by using a water/oil microemulsion method. Stable electrochemiluminescence (ECL) was obtained when the RuSi nanoparticles were immobilized on a glassy carbon electrode by using tripropylamine (TPA) as a coreactant. Furthermore, the ECL of the RuSi nanoparticles with layer-by-layer biomolecular coatings was investigated. Squential self-assembly of the polyelectrolytes and biomolecules on the RuSi nanoparticles gave nanocomposite suspensions, the ECL of which decreased on increasing the number of bilayers. Moreover, factors that affected the assembly and ECL signals were investigated. The decrease in ECL could be assigned to steric hindrance and limited diffusion of the coreactant molecules in the silica matrix after they were attached to the biomolecules. Since surface modification of the RuSi nanoparticles can improve their biocompatibility and prevent leaking of the [Ru(bpy)3]2+ ions, the RuSi nanoparticles can be readily used as efficient and stable ECL tag materials in immunoassay and DNA detection. PMID:18306266

  3. N-trimethylchitosan/alginate layer-by-layer self assembly coatings act as "fungal repellents" to prevent biofilm formation on healthcare materials.

    Science.gov (United States)

    Jiang, Fuguang; Yeh, Chih-Ko; Wen, Jianchuan; Sun, Yuyu

    2015-02-18

    Fungal biofilm formation on healthcare materials is a significant clinical concern, often leading to medical-device-related infections, which are difficult to treat. A novel fungal repellent strategy is developed to control fungal biofilm formation. Methylacrylic acid (MAA) is grated onto poly methyl methacrylate (PMMA)-based biomaterials via plasma-initiated grafting polymerization. A cationic polymer, trimethylchitosan (TMC), is synthesized by reacting chitosan with methyl iodide. Sodium alginate (SA) is used as an anionic polymer. TMC/SA multilayers are coated onto the MAA-grafted PMMA via layer-by-layer self-assembly. The TMC/SA multilayer coatings significantly reduce fungal initial adhesion, and effectively prevent fungal biofilm formation. It is concluded that the anti-adhesive property of the surface is due to its hydrophilicity, and that the biofilm-inhibiting action is attributed to the antifungal activity of TMC as well as the chelating function of TMC and SA, which may have acted as fungal repellents. Phosphate buffered saline (PBS)-immersion tests show that the biofilm-modulating effect of the multilayer coatings is stable for more than 4 weeks. Furthermore, the presence of TMC/SA multilayer coatings improves the biocompatibility of the original PMMA, offering a simple, yet effective, strategy for controlling fungal biofilm formation. PMID:25295485

  4. Controllable fabrication of nanostructured materials for photoelectrochemical water splitting via atomic layer deposition.

    Science.gov (United States)

    Wang, Tuo; Luo, Zhibin; Li, Chengcheng; Gong, Jinlong

    2014-11-21

    Photoelectrochemical (PEC) water splitting is an attractive approach to generate hydrogen as a clean chemical fuel from solar energy. But there remain many fundamental issues to be solved, including inadequate photon absorption, short carrier diffusion length, surface recombination, vulnerability to photo-corrosion, and unfavorable reaction kinetics. Owing to its self-limiting surface reaction mechanism, atomic layer deposition (ALD) is capable of depositing thin films in a highly controllable manner, which makes it an enabling technique to overcome some of the key challenges confronted by PEC water splitting. This tutorial review describes some unique and representative applications of ALD in fabricating high performance PEC electrodes with various nanostructures, including (i) coating conformal thin films on three-dimensional scaffolds to facilitate the separation and migration of photocarriers and enhance light trapping, as well as realizing controllable doping for bandgap engineering and forming homojunctions for carrier separation; (ii) achieving surface modification through deposition of anti-corrosion layers, surface state passivation layers, and surface catalytic layers; and (iii) identifying the main rate limiting steps with model electrodes with highly defined thickness, composition, and interfacial structure. PMID:24500041

  5. Trapping and depth profile of tritium in surface layers of metallic materials

    Energy Technology Data Exchange (ETDEWEB)

    Matsuyama, M., E-mail: masao@ctg.u-toyama.ac.jp [Hydrogen Isotope Research Center, University of Toyama, Gofuku 3190, Toyama 930-8555 (Japan); Chen, Z. [The Southwestern Institute of Physics, Chengdu 610041, Sichuan (China); Nisimura, K. [National Institute for Fusion Science, Toki 509-5292 (Japan); Akamaru, S.; Torikai, Y.; Hatano, Y. [Hydrogen Isotope Research Center, University of Toyama, Gofuku 3190, Toyama 930-8555 (Japan); Ashikawa, N. [National Institute for Fusion Science, Toki 509-5292 (Japan); Oya, Y.; Okuno, K. [Radiochemistry Research Laboratory, Shizuoka University, Shizuoka 422-8529 (Japan); Hino, T. [Laboratory of Plasma Physics and Engineering, Hokkaido University, Sapporo 060-8628 (Japan)

    2011-10-01

    Tritium amount retained in surface layers and release behavior from surface layers were examined using SS316L samples exposed to plasmas in the Large Helical Device and a commercial Cu-Be alloy plate. BIXS analyses and observation by SEM indicate that carbon and titanium deposited on the plasma-facing surface of the SS316L samples. Larger amount of tritium was trapped in the plasma-facing surface in comparison with the polished surface. Higher enrichment of tritium in surface layers was similarly found in the polished surface of both samples. The amount of surface tritium in both samples was almost same, while the bulk concentration of tritium in Cu-Be was much lower than that in SS316L. Tritium release from the SS316L and Cu-Be samples into water was examined by immersion experiments. Tritium elution was observed for both samples, but changes in the residual tritium amount in surface layers were different from each other.

  6. Molecular plating of thin lanthanide layers with improved material properties for nuclear applications

    International Nuclear Information System (INIS)

    This work describes experiments to gain an improved understanding of the processes associated with the electrochemical production of thin lanthanide layers for nuclear science investigations, i.e., nuclear targets. Nd, Sm, and Gd layers were prepared by means of the so-called molecular plating (MP) technique, where electrodeposition from an organic medium is usually performed in the constant current mode using two-electrode cells. The obtained results allowed the identification of optimized production conditions, which led to a significantly improved layer quality. Constant current density MP is a mass-transport controlled process. The applied current is maintained constant by constant fluxes of electroactive species towards the cathode - where the layer is grown - and the anode. The investigations showed the cell potentials of the electrodeposition systems to be always dominated by the ohmic drop produced by the resistance of the solutions used for the studies. This allowed to derive an expression relating cell potential with concentration of the electroactive species. This expression is able to explain the trends recorded with different electrolyte concentrations and it serves as a basis to get towards a full understanding of the reasons leading to the characteristic minima observed in the evolution of the cell potential curves with time. The minima were found to correspond to an almost complete depletion of the Nd ions obtained by dissolution of the model salt used for the investigations. Nd was confirmed to be deposited at the cathode as derivatives of Nd3+ - possibly as carboxylate, oxide or hydroxide. This fact was interpreted on the basis of the highly negative values of the standard redox potentials typical for lanthanide cations. Among the different electroactive species present in the complex MP solutions, the Nd3+ ions were found to contribute to less than 20% to the total current. Because of electrolysis, also the mixed solvent contributed to the applied constant current as an electroactive species. The presence of electrolyzed solvent was confirmed by the analysis of the produced deposits, which were always covered by both chemisorbed and physisorbed solvent molecules. Target characterizations showed the surfaces of the layers to present severe cracks, which were found to form during the drying time after completion of the MP. Different drying environments, i.e., air or Ar, did not affect the deposits. The drying-related nature of cracking and the solvent composition of the produced layers suggested to perform constant current density MPs using solvents with significantly different physical properties, most notably the boiling point. N,N-dimethylformamide (DMF), i.e., the highest boiling point solvent, proved to be very effective for the production of crack-free surfaces. DMF, in combination with the use of very smooth deposition substrates, allowed the growth of smooth, defectless layers, which likely underwent smaller stress during drying than the deposits produced by using rougher substrates and more volatile solvents. The roughness of the deposition substrate and the solvent used for the platings proved then to be core factors for the preparation of high quality layers. MP thus showed to be very effective for the production of uniform and homogeneous targets with excellent yield. Tests of the performance of layers produced by MP as α-particle sources were also carried out. 147Sm was used as model isotope for the α spectroscopy investigations. Both peak resolution and the fraction of α particles reaching the detector were found to be influenced by source effects. These effects were categorized according to different ''layer variables'', i.e., variables influencing the α spectra by means of ''layer effects'', and were found to be promoted by the plating solvent and the roughness of the deposition substrate used to perform the MPs. These parameters likely affected thickness, morphology, and growth mode of the layers. The layer variables proved to alter the relative detection efficiencies of the α measurements by as much as 15%. Only the uniform and homogeneous layers produced by MP from DMF using the smoothest deposition substrate available turned out to be optimum α-particle sources. The results obtained from this work open the way to an improved production of nuclear targets by means of molecular plating. Future applications include in particular the preparation of targets to be used in neutron-induced fission experiments and in low-background, low-activity α measurements.

  7. Fundamental degradation mechanisms of layered oxide Li-ion battery cathode materials: Methodology, insights and novel approaches

    Energy Technology Data Exchange (ETDEWEB)

    Hausbrand, R., E-mail: hausbrand@surface.tu-darmstadt.de; Cherkashinin, G.; Ehrenberg, H.; Grting, M.; Albe, K.; Hess, C.; Jaegermann, W.

    2015-02-15

    Graphical abstract: - Highlights: Description of recent in operando and in situ analysis methodology. Surface science approach using photoemission for analysis of cathode surfaces and interfaces. Ageing and fatigue of layered oxide Li-ion battery cathode materials from the atomistic point of view. Defect formation and electronic structure evolution as causes for cathode degradation. Significance of interfacial energy alignment and contact potential for side reactions. - Abstract: This overview addresses the atomistic aspects of degradation of layered LiMO{sub 2} (M = Ni, Co, Mn) oxide Li-ion battery cathode materials, aiming to shed light on the fundamental degradation mechanisms especially inside active cathode materials and at their interfaces. It includes recent results obtained by novel in situ/in operando diffraction methods, modelling, and quasi in situ surface science analysis. Degradation of the active cathode material occurs upon overcharge, resulting from a positive potential shift of the anode. Oxygen loss and eventual phase transformation resulting in dead regions are ascribed to changes in electronic structure and defect formation. The anode potential shift results from loss of free lithium due to side reactions occurring at electrode/electrolyte interfaces. Such side reactions are caused by electron transfer, and depend on the electron energy level alignment at the interface. Side reactions at electrode/electrolyte interfaces and capacity fade may be overcome by the use of suitable solid-state electrolytes and Li-containing anodes.

  8. Fundamental degradation mechanisms of layered oxide Li-ion battery cathode materials: Methodology, insights and novel approaches

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: Description of recent in operando and in situ analysis methodology. Surface science approach using photoemission for analysis of cathode surfaces and interfaces. Ageing and fatigue of layered oxide Li-ion battery cathode materials from the atomistic point of view. Defect formation and electronic structure evolution as causes for cathode degradation. Significance of interfacial energy alignment and contact potential for side reactions. - Abstract: This overview addresses the atomistic aspects of degradation of layered LiMO2 (M = Ni, Co, Mn) oxide Li-ion battery cathode materials, aiming to shed light on the fundamental degradation mechanisms especially inside active cathode materials and at their interfaces. It includes recent results obtained by novel in situ/in operando diffraction methods, modelling, and quasi in situ surface science analysis. Degradation of the active cathode material occurs upon overcharge, resulting from a positive potential shift of the anode. Oxygen loss and eventual phase transformation resulting in dead regions are ascribed to changes in electronic structure and defect formation. The anode potential shift results from loss of free lithium due to side reactions occurring at electrode/electrolyte interfaces. Such side reactions are caused by electron transfer, and depend on the electron energy level alignment at the interface. Side reactions at electrode/electrolyte interfaces and capacity fade may be overcome by the use of suitable solid-state electrolytes and Li-containing anodes

  9. Fixed, Fluid, and Transient: Negotiating Layers of Art Classroom Material Culture

    Science.gov (United States)

    Woywod, Christine

    2015-01-01

    Objects of material culture have meaning. American flags, worktables, bulletin boards, interactive whiteboards, and large white-faced clocks signify "classroom" while color wheels, cupboards, cabinets, sinks, drawing supplies, and that particular scent that lingers after years of exposure to painting materials even more specifically

  10. A sparse digital signal model for ultrasonic nondestructive evaluation of layered materials.

    Science.gov (United States)

    Bochud, N; Gomez, A M; Rus, G; Peinado, A M

    2015-09-01

    Signal modeling has been proven to be an useful tool to characterize damaged materials under ultrasonic nondestructive evaluation (NDE). In this paper, we introduce a novel digital signal model for ultrasonic NDE of multilayered materials. This model borrows concepts from lattice filter theory, and bridges them to the physics involved in the wave-material interactions. In particular, the proposed theoretical framework shows that any multilayered material can be characterized by a transfer function with sparse coefficients. The filter coefficients are linked to the physical properties of the material and are analytically obtained from them, whereas a sparse distribution naturally arises and does not rely on heuristic approaches. The developed model is first validated with experimental measurements obtained from multilayered media consisting of homogeneous solids. Then, the sparse structure of the obtained digital filter is exploited through a model-based inverse problem for damage identification in a carbon fiber-reinforced polymer (CFRP) plate. PMID:26092090

  11. Bulk and surface acoustic waves in solid-fluid Fibonacci layered materials.

    Science.gov (United States)

    Quotane, I; El Boudouti, E H; Djafari-Rouhani, B; El Hassouani, Y; Velasco, V R

    2015-08-01

    We study theoretically the propagation and localization of acoustic waves in quasi-periodic structures made of solid and fluid layers arranged according to a Fibonacci sequence. We consider two types of structures: either a given Fibonacci sequence or a periodic repetition of a given sequence called Fibonacci superlattice. Various properties of these systems such as: the scaling law and the self-similarity of the transmission spectra or the power law behavior of the measure of the energy spectrum have been highlighted for waves of sagittal polarization in normal and oblique incidence. In addition to the allowed modes which propagate along the system, we study surface modes induced by the surface of the Fibonacci superlattice. In comparison with solid-solid layered structures, the solid-fluid systems exhibit transmission zeros which can break the self-similarity behavior in the transmission spectra for a given sequence or induce additional gaps other than Bragg gaps in a periodic structure. PMID:25819878

  12. Experimental study of shielding layer plasma radiation at high power plasma-material interaction

    International Nuclear Information System (INIS)

    Some results of the study of radiation of shielding layer plasma in visible and VUV regions of spectrum during high power (Pirr ? 10 MW/cm2) plasma irradiation to targets (graphite and tungsten) are given in the report. It is observed the difference of some radiation characteristics in dependence of registration direction. It is concluded that visible radiation power flux on the target surface can be characterised by quasistationary level during irradiation. (author)

  13. Mass exchange in adjacent layers of grain material stored in silo

    Directory of Open Access Journals (Sweden)

    Bilański W.K.

    1998-06-01

    Full Text Available The paper presents the results of a study on the process of moisture diffusion during barley grain storage in a grain storage silo. The moisture migration was caused by concentration gradient. The study was conducted using a model test station and consisted in the measurement of barley grain moisture and temperature in a silo, and in measuring the pressure exerted by the grain bulk on the silo wall. Analysis of the results showed that none of the parameters studied was stable. It was found that when the grain moisture content applied was 16% in the bottom layer and 10% in the upper layer the average value of grain moisture content in the silo increased from 13.2% to 14.1% over the ten days of the process, while with reverse positioning of the layers in the silo the corresponding increase reached 13.8%. This was due to additional precipitation of water in the course of the process of grain respiration. Moisture diffusion caused an increase in the temperature of the grain within the silo (up to 33°C at ambient temperature of 16°C. Another important effect of the moisture diffusion was the swelling of grains, which caused an increase in the pressure of the barley grain bulk against the silo wall. The highest increase in the wall load was observed at the boundary line between layers of grain of different moisture content levels. The changes in the values of the parameters under study were described by means of regression equations.

  14. Long-term self-assembly of inorganic layered materials influenced by the local states of the interlayer cations.

    Science.gov (United States)

    Sato, Kiminori; Numata, Kazuomi; Dai, Weili; Hunger, Michael

    2014-06-14

    A wide variety of parameters as, e.g., temperature, humidity, particle size, and cation state are known to influence the agglomeration process of two-dimensional (2D) nanosheets, called self-assembly, in inorganic layered materials. The detailed studies on which parameters are decisive and how they influence the self-assembly, however, have not been performed yet. Here, the long-term self-assembly was studied for layered stevensite and hectorite, and compared with our previous data of saponite for elucidating an influence of local states of the interlayer cations. The results were analyzed with respect to a recently established rheological model, in which 2D nanosheets migrate parallel to the layer direction aided by water molecules as lubricants [K. Sato et al., J. Phys. Chem. C, 2012, 116, 22954]. With decreasing the strength of the local electric fields facing to the interlayer spaces, cation positions split into two or three, which makes the distribution of water molecules more uniformly. These water molecules enhance the rheological motion of the 2D nanosheets parallel to the layer direction, thus accelerating the self-assembly process. PMID:24770790

  15. Preparation and Characterization of TiO2/CdS Layers as Potential Photoelectrocatalytic Materials

    Directory of Open Access Journals (Sweden)

    Teofil-Danut Silipas

    2011-01-01

    Full Text Available The TiO2/CdS semiconductor composites were prepared on
    indium tin oxide (ITO substrates in di®erent mass proportions via wet-chemical techniques using bi-distilled water, acetyl-acetone, poly-propylene-glycol and Triton X-100 as additives. The composite layers were annealed in normal conditions at the temperature of 450±C, 120 min. with a rate of temperature increasing of 5±C/min. The structural and optical properties of all the TiO2/CdS ayers were characterized by X-ray di®raction, UV-VIS spectroscopy, spectrofluorimetry and FT/IR microscopy. The microstructural properties of the deposited TiO2/CdS layers can be modi¯ed by varying the mass proportions of TiO2:CdS. The good crystallinity level and the high optical adsorption of
    the TiO2/CdS layers make them attractive for photoelectrochemical cell applications.

  16. Effect of constraining layer stiffness on performance of damping tile materials using finite element modelling with Rayleigh integral

    Science.gov (United States)

    Orzechowski, Jeffrey M.; Landmann, Alan E.

    Three different materials are proposed as options for high-leverage constrained-layer acoustical damping tiles when applied to an aircraft skin with stringers. The finite element method is used to calculate the complex velocity at an array of positions on the surface of the structure. Far-field radiated mean square pressure, between 350 and 1000 Hz, is then calculated from these complex velocities using the Rayleigh integral. This methodology is applied to evaluate damping tile performance as a function of material flexural modulus. Each configuration studied has identical geometry and viscoelastic material but varies in tile flexural modulus only. The results indicate that sound transmission reduction performance increases significantly with increasing damping tile flexural modulus.

  17. A Monte Carlo code for simulating soft X-ray absorption in pure and two-layer materials

    International Nuclear Information System (INIS)

    The present paper describes a Monte Carlo code to simulate the cascade of electron-hole pairs and phonons generated when a low-energy X-ray photon is absorbed by a material. The model has been applied to study the response to UV or soft X-ray radiation of diamond and silicon, focused on the case of two-layer material made of diamond film grown on silicon. Typically the statistical distribution of the electron-hole cascade is macroscopically parameterized by the mean energy required to create an electron-hole pair W and the Fano factor F. The results for the pure materials are in agreement with the values present in the literature. Moreover we found an enhancement of the Fano factor and a super-Poissonian behaviour of the statistical distribution of the pairs, typical of correlated systems.

  18. Characterization of candidate materials in SCWR conditions - Estimation of kinetic parameters of individual corrosion layer constituents

    International Nuclear Information System (INIS)

    Understanding of corrosion phenomena of candidate materials under SCWR (Supercritical Water Reactor) conditions necessitates a reliable experimental testing of such materials and also a development of modelling techniques for the relevant conditions. The long term objective of this work is to perform a study that would serve as a guide for the selection of in-core materials for the European HPLWR (High Performance Light Water Reactor). One of the key performance indicators for the material selection is the corrosion and oxidation behaviour of materials in SCWR conditions. Therefore, a combination of in-situ studies with ex-situ analytical characterisation of the oxide films forming on the internal component candidate materials in contact with supercritical water are needed. In the present paper, a first step towards employing a model for the in-depth contents of individual metallic constituents (i.e. Fe, Cr, Ni, Mn) to estimate the kinetic and transport parameters of the oxidation process in SCWR conditions is performed. A preliminary description of the model concept and the calculation procedure for ferritic-martensitic (F/M) steel P91 and austenitic stainless steel AISI 316L(NG) are presented. For the purpose, selected material samples were analyzed using glow discharge optical emission spectroscopy (GDOES) and scanning electron microscopy (SEM) to determine the in-depth composition of the formed oxides. (authors)

  19. Bonding Semiconductor Laser Chips: Substrate Material Figure of Merit and Die Attach Layer Influence

    OpenAIRE

    Pliska, A.-C.; Mottin, J.; Matuschek, N.; Bosshard, C.

    2005-01-01

    The coefficient of thermal expansion (CTE) and the thermal conductivity are the two key parameters to consider when selecting a particular substrate material for a die bonding process. We will discuss here a model to determine the substrate material giving the best chip reliability expectations for GaAs and InP laser chips. In that respect, a comparison of the thermo-mechanical stresses induced during the soldering process of GaAs and InP semiconductor chips on different substrate materials u...

  20. Three-Dimensional Finite Element Simulations for the Thermal Characteristics of PCRAMs with Different Buffer Layer Materials

    International Nuclear Information System (INIS)

    Simulation of the heat consumption in phase change random access memories (PCRAMs) is investigated by a three-dimensional finite element model. It is revealed that the thermal conductivity and electrical conductivity of the buffer layer are crucial in controlling the heating efficiency in RESET process. The buffer layer materials W, TiN, WO3, TiO2 and poly-germanium (poly-Ge) are applied in the simulation respectively, and compared with each other. The simulation results show that limitation of electrical conductivity is effective on heating efficiency and the limitation of thermal conductivity is important on the reliable RESET process. (cross-disciplinary physics and related areas of science and technology)

  1. Highly condensed fluorinated methacrylate hybrid material for transparent low-kappa passivation layer in LCD-TFT.

    Science.gov (United States)

    Oh, Ji-Hoon; Kwak, Seung-Yeon; Yang, Seung-Cheol; Bae, Byeong-Soo

    2010-03-01

    Photocurable and highly condensed fluorinated methacrylate oligosiloxane, with a low dielectric constant (kappa = 2.54), was prepared by a nonhydrolytic sol-gel condensation reaction. The oligosiloxane resin was then spin-coated, photocured, and thermally baked in order to fabricate a fluorinated methacrylate hybrid material (FM hybrimer) thin film. This study investigated the application of this FM hybrimer film as a low-kappa passivation layer in LCD-based thin film transistors (TFT). It was found that a dielectric constant as low as kappa = 2.54 could be obtained, without introducing pores in the dense FM hybrimer films. This study compares FM hybrimer film characteristics with those required for passivation layers in LCD-TFTs, including thermal stability, optical transmittance, hydrophobicity, gap fill, and planarization effects as well as electrical insulation. PMID:20356298

  2. New diffusion protective layers on constructional materials used in aggressive chemical environments

    International Nuclear Information System (INIS)

    The review of materials and protective coatings for constructions working in aggressive chemical conditions have been done. The new trends and solutions have been performed. Manufacturing and properties of Si-B protective coatings in comparison with other corrosion resistant materials have been described. It has been shown the better anticorrosive properties of elaborated Si-B coatings manufactured in the diffusion powder process than specified for stainless steels dedicated for working in chemical aggressive conditions. (author)

  3. Sacrificial structures for deep reactive ion etching of high-aspect ratio kinoform silicon x-ray lenses

    DEFF Research Database (Denmark)

    Sthr, Frederik; Michael-Lindhard, Jonas

    2015-01-01

    This article describes the realization of complex high-aspect ratio silicon structures with feature dimensions from 100 lm to 100nm by deep reactive ion etching using the Bosch process. As the exact shape of the sidewall profiles can be crucial for the proper functioning of a device, the authors investigated how sacrificial structures in the form of guarding walls and pillars may be utilized to facilitate accurate control of the etch profile. Unlike other sacrificial structuring approaches, no silicon-on-insulator substrates or multiple lithography steps are required. In addition, the safe removal of the sacrificial structures was accomplished by thermal oxidation and subsequent selective wet etching. The effects of the dimensions and relative placement of sacrificial walls and pillars on the etching result were determined through systematic experiments. The authors applied this process for exact sidewall control in the manufacture of x-ray lenses that are very sensitive to sidewall shape nonuniformities. Compound kinoform lenses for focusing hard x-rays with structure heights of 200 lm were manufactured, and the lenses were tested in terms of their focusing ability and refracting qualities using synchrotron radiation at a photon energy of 17 keV. A 180 lm long line focus with a waist of 430 nm at a focal length of 215mm was obtained.

  4. Enhanced photon absorption in spiral nanostructured solar cells using layered 2D materials

    Science.gov (United States)

    Tahersima, Mohammad H.; Sorger, Volker J.

    2015-08-01

    Recent investigations of semiconducting two-dimensional (2D) transition metal dichalcogenides have provided evidence for strong light absorption relative to its thickness attributed to high density of states. Stacking a combination of metallic, insulating, and semiconducting 2D materials enables functional devices with atomic thicknesses. While photovoltaic cells based on 2D materials have been demonstrated, the reported absorption is still just a few percent of the incident light due to their sub-wavelength thickness leading to low cell efficiencies. Here we show that taking advantage of the mechanical flexibility of 2D materials by rolling a molybdenum disulfide (MoS2)/graphene (Gr)/hexagonal boron nitride stack to a spiral solar cell allows for optical absorption up to 90%. The optical absorption of a 1 ?m long hetero-material spiral cell consisting of the aforementioned hetero stack is about 50% stronger compared to a planar MoS2 cell of the same thickness; although the volumetric absorbing material ratio is only 6%. A core-shell structure exhibits enhanced absorption and pronounced absorption peaks with respect to a spiral structure without metallic contacts. We anticipate these results to provide guidance for photonic structures that take advantage of the unique properties of 2D materials in solar energy conversion applications.

  5. Simulation of Sputtering Damage of Tungsten Coating Layer on First Wall Materials of a Fusion Reactor

    International Nuclear Information System (INIS)

    First Wall (FW) structural materials of fusion reactors, such as International Thermonuclear Experimental Reactor (ITER), are subjected to transient loads (disruptions, ELMs, and VDE) resulting in the loss of integrity from erosion/deposition processes. The dominant mechanism for erosion of Plasma Facing Component (PFC) materials is sputtering by which atoms from the surface of solid are ejected due to interaction with energetic plasma ions. Simulation of such trajectories of ions is used to calculate sputtering yields further estimating lifetime of materials. Tungsten coating on FW materials such as tungsten (W) and Carbon Fiber Composites (CFC) has been considered to compensate for this loss of eroded materials. In this study, a computational simulation of sputtering of W coating on W and CFC target was performed to incorporate physical interpretation of impact of coating density and surface binding energy (adhesion) on target damage behaviors. In variation of tungsten coating density, TRIM simulation on 3D target damage on tungsten substrate is carried out. For the higher coating density, the less target damage occurs. Surface binding energy modification seems to have no effect on sputtering yield of coating at all. Balancing of coating density and adhesion needs to be optimized Experimental validation of such results is to carry out for FW candidate target materials such as CFC and W by PS and PVD coating technique

  6. Simulation of Sputtering Damage of Tungsten Coating Layer on First Wall Materials of a Fusion Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyunmyung; Lee, Ho Jung; Jang, Changheui [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2014-05-15

    First Wall (FW) structural materials of fusion reactors, such as International Thermonuclear Experimental Reactor (ITER), are subjected to transient loads (disruptions, ELMs, and VDE) resulting in the loss of integrity from erosion/deposition processes. The dominant mechanism for erosion of Plasma Facing Component (PFC) materials is sputtering by which atoms from the surface of solid are ejected due to interaction with energetic plasma ions. Simulation of such trajectories of ions is used to calculate sputtering yields further estimating lifetime of materials. Tungsten coating on FW materials such as tungsten (W) and Carbon Fiber Composites (CFC) has been considered to compensate for this loss of eroded materials. In this study, a computational simulation of sputtering of W coating on W and CFC target was performed to incorporate physical interpretation of impact of coating density and surface binding energy (adhesion) on target damage behaviors. In variation of tungsten coating density, TRIM simulation on 3D target damage on tungsten substrate is carried out. For the higher coating density, the less target damage occurs. Surface binding energy modification seems to have no effect on sputtering yield of coating at all. Balancing of coating density and adhesion needs to be optimized Experimental validation of such results is to carry out for FW candidate target materials such as CFC and W by PS and PVD coating technique.

  7. Shape-selective sieving layers on an oxide catalyst surface

    Science.gov (United States)

    Canlas, Christian P.; Lu, Junling; Ray, Natalie A.; Grosso-Giordano, Nicolas A.; Lee, Sungsik; Elam, Jeffrey W.; Winans, Randall E.; van Duyne, Richard P.; Stair, Peter C.; Notestein, Justin M.

    2012-12-01

    New porous materials such as zeolites, metal-organic frameworks and mesostructured oxides are of immense practical utility for gas storage, separations and heterogeneous catalysis. Their extended pore structures enable selective uptake of molecules or can modify the product selectivity (regioselectivity or enantioselectivity) of catalyst sites contained within. However, diffusion within pores can be problematic for biomass and fine chemicals, and not all catalyst classes can be readily synthesized with pores of the correct dimensions. Here, we present a novel approach that adds reactant selectivity to existing, non-porous oxide catalysts by first grafting the catalyst particles with single-molecule sacrificial templates, then partially overcoating the catalyst with a second oxide through atomic layer deposition. This technique is used to create sieving layers of Al2O3 (thickness, 0.4-0.7 nm) with nanocavities (<2 nm in diameter) on a TiO2 photocatalyst. The additional layers result in selectivity (up to 9:1) towards less hindered reactants in otherwise unselective, competitive photocatalytic oxidations and transfer hydrogenations.

  8. New hybrid material based on layered double hydroxides and biogenic silver nanoparticles: antimicrobial activity and cytotoxic effect

    Scientific Electronic Library Online (English)

    Priscyla D., Marcato; Natlia V., Parizotto; Diego Stfani T., Martinez; Amauri J., Paula; Iasmin R., Ferreira; Patrcia S., Melo; Nelson, Durn; Oswaldo L., Alves.

    2013-02-01

    Full Text Available Hidrxidos duplos lamelares (HDLs) tm sido amplamente investigados devido s suas diversas aplicaes nas indstrias de materiais e biotecnologia. A combinao de nanopartculas de prata com o material biocompatvel HDL pode criar um novo material hbrido com novas propriedades sinergsticas. Neste [...] trabalho, nanopartculas de prata biognicas (AgNPbio) foram associadas com Mg-Al HDL para obter o material hbrido HDL-AgNPbio. O novo material hbrido obtido foi caracterizado por difratometria de raios X (XRD), microscopias eletrnica de transmisso (TEM) e de varredura com espectroscopia de energia dispersiva por raios-X (MEV-EDS), espectrometria de emisso atmica por plasma acoplado indutivamente (ICP-OES) e espectroscopia na regio do infravermelho com transformada de Fourier (FTIR). O HDL foi eficiente em adsorver nanopartculas de prata devido carga superficial oposta entre as AgNPbio (? = -13,2 mV) e o HDL (? = +3,2 mV). Alm disso, as AgNPbio no foram lixiviadas do material hbrido, mesmo aps cinco ciclos de lavagem, indicando uma forte interao. Uma importante propriedade deste material hbrido foi a sua atividade antimicrobiana contra Staphylococcus aureus e Escherichia coli e ausncia de efeito citotxico em clulas de fibroblastos (V79). Este material hbrido um interessante e promissor nanobiocompsito para aplicaes biomdicas e cosmticas. Abstract in english Layered double hydroxides (LDHs) have been widely investigated due to their several applications in the material and biotechnology industries. The combination of silver nanoparticles with biocompatible LDH material can create a new hybrid material with new properties. In this work, biogenic silver n [...] anoparticles (AgNPbio) were associated with Mg-Al LDH to obtain the hybrid material LDH-AgNPbio. The new hybrid material obtained was characterized by X-ray diffractometry (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), transmission electron microscopy (TEM), inductively coupled plasma optical emission spectrometry (ICP-OES) and Fourier transform infrared spectroscopy (FTIR). LDH was efficient to absorb silver nanoparticles due to an opposite surface charge between AgNPbio (? = -13.2 mV) and LDH (? = +3.2 mV). Furthermore, AgNPbio was not lixiviated from LDH-AgNPbio, even after five washes, indicating a strong interaction. An important property of this hybrid material was its antimicrobial activity against Staphylococcus aureus and Escherichia coli and absence of cytotoxic effect to fibroblast cell (V79). This hybrid material is an interesting and promising nanobiocomposite for biomedical and cosmetic applications.

  9. Transport properties of Layer-Antiferromagnet CuCrS2: A possible thermoelectric material

    OpenAIRE

    Tewari, G. C.; Tripathi, T S; Rastogi, A. K.

    2009-01-01

    The electrical, thermal conductivity and Seebeck coefficient of the quenched, annealed and slowly cooled phases of the layer compound CuCrS2 have been reported between 15K to 300K. We also confirm the antiferromagnetic transition at 40K in them by our magnetic measurements between 2K and 300K. The crystal flakes show a minimum around 100K in their in-plane resistance behavior. For the polycrystalline pellets the resistivity depends on their flaky texture and it attains at mo...

  10. Aligned carbon nanotube film enables thermally induced state transformations in layered polymeric materials.

    Science.gov (United States)

    Lee, Jeonyoon; Stein, Itai Y; Kessler, Seth S; Wardle, Brian L

    2015-04-29

    The energy losses and geometric constraints associated with conventional curing techniques of polymeric systems motivate the study of a highly scalable out-of-oven curing method using a nanostructured resistive heater comprised of aligned carbon nanotubes (A-CNT). The experimental results indicate that, when compared to conventional oven based techniques, the use of an "out-of-oven" A-CNT integrated heater leads to orders of magnitude reductions in the energy required to process polymeric layered structures such as composites. Integration of this technology into structural systems enables the in situ curing of large-scale polymeric systems at high efficiencies, while adding sensing and control capabilities. PMID:25872577

  11. Thermal shock problem of a generalized thermoelastic layered composite material with variable thermal conductivity

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available The dynamic treatment of one-dimensional generalized thermoelastic problem of heat conduction is made for a layered thin plate which is exposed to a uniform thermal shock taking into account variable thermal conductivity. The basic equations are transformed by Laplace transform and solved by a direct method. The solution was applied for a plate of sandwich structure, which is thermally shocked, and is traction-free in the outer sides. The inverses of Laplace transforms are obtained numerically. The temperature, the stress, and the displacement distributions are represented graphically.

  12. Preparation and Characterization of TiO2/CdS Layers as Potential Photoelectrocatalytic Materials

    OpenAIRE

    Teofil-Danut Silipas; Ioan Bratu; Simina-Virginia Dreve; Ramona-Crina Suciu; Marcela-Corina Rosu; Emil Indrea

    2011-01-01

    The TiO2/CdS semiconductor composites were prepared on
    indium tin oxide (ITO) substrates in dierent mass proportions via wet-chemical techniques using bi-distilled water, acetyl-acetone, poly-propylene-glycol and Triton X-100 as additives. The composite layers were annealed in normal conditions at the temperature of 450C, 120 min. with a rate of temperature increasing of 5C/min. The structural and optical properties of all the TiO2/CdS ayers were ch...

  13. Mass transfer across combustion gas thermal boundary layers - Power production and materials processing implications

    Science.gov (United States)

    Rosner, D. E.

    1985-01-01

    The effects of Soret diffusion (for vapors) and thermophoresis (for particles) are illustrated using recent optical experiments and boundary layer computations. Mass transfer rate augmentations of up to a factor of 1000 were observed and predicted for submicron-particle capture by cooled solid surfaces, while mass transfer suppressions of more than 10 to the -10th-fold were predicted for 'overheated' surfaces. It is noted that the results obtained are of interest in connection with such technological applications as fly-ash capture in power generation equipment and glass droplet deposition in optical-waveguide manufacture.

  14. Forward problem of resonant ultrasound spectroscopy for identification of material properties of thin layers.

    Czech Academy of Sciences Publication Activity Database

    Kruisov, Alena; R?ek, M.; Sedlk, Petr; Seiner, Hanu; Landa, Michal; Kolman, Radek

    Pilsen : University of West Bohemia, Pilsen, 2010 - (Admek, V.; Zaj?ek, M.). s. 1-2 ISBN 978-80-7043-919-7. [Conference with international parcipationCM 2010 /26./. 08.11.2010-10.11.2010, Ne?tiny] R&D Projects: GA ?R(CZ) GA101/09/0702 Institutional research plan: CEZ:AV0Z20760514 Keywords : resonant ultrasound spectroscopy (RUS) * elastic properties of thin layers Subject RIV: BI - Acoustics http://www.kme.zcu.cz/vm2010

  15. Engineering topological superconductors using surface atomic-layer/molecule hybrid materials.

    Science.gov (United States)

    Uchihashi, Takashi

    2015-08-28

    Surface atomic-layer (SAL) superconductors consisting of epitaxially grown metal adatoms on a clean semiconductor surface have been recently established. Compared to conventional metal thin films, they have two important features: (i) space-inversion symmetry-breaking throughout the system and (ii) high sensitivity to surface adsorption of foreign species. These potentially lead to manifestation of the Rashba effect and a Zeeman field exerted by adsorbed magnetic organic molecules. After introduction of the archetypical SAL superconductor Si(111)-(√7 × √3)-In, we describe how these features are utilized to engineer a topological superconductor with Majorana fermions and discuss its promises and expected challenges. PMID:26234824

  16. Flexible n-type thermoelectric materials by organic intercalation of layered transition metal dichalcogenide TiS2

    Science.gov (United States)

    Wan, Chunlei; Gu, Xiaokun; Dang, Feng; Itoh, Tomohiro; Wang, Yifeng; Sasaki, Hitoshi; Kondo, Mami; Koga, Kenji; Yabuki, Kazuhisa; Snyder, G. Jeffrey; Yang, Ronggui; Koumoto, Kunihito

    2015-06-01

    Organic semiconductors are attracting increasing interest as flexible thermoelectric materials owing to material abundance, easy processing and low thermal conductivity. Although progress in p-type polymers and composites has been reported, their n-type counterpart has fallen behind owing to difficulties in n-type doping of organic semiconductors. Here, we present an approach to synthesize n-type flexible thermoelectric materials through a facile electrochemical intercalation method, fabricating a hybrid superlattice of alternating inorganic TiS2 monolayers and organic cations. Electrons were externally injected into the inorganic layers and then stabilized by organic cations, providing n-type carriers for current and energy transport. An electrical conductivity of 790 S cm-1 and a power factor of 0.45 mW m-1 K-2 were obtained for a hybrid superlattice of TiS2/[(hexylammonium)x(H2O)y(DMSO)z], with an in-plane lattice thermal conductivity of 0.12 0.03 W m-1 K-1, which is two orders of magnitude smaller than the thermal conductivities of the single-layer and bulk TiS2. High power factor and low thermal conductivity contributed to a thermoelectric figure of merit, ZT, of 0.28 at 373 K, which might find application in wearable electronics.

  17. Flexible n-type thermoelectric materials by organic intercalation of layered transition metaldichalcogenide TiS2.

    Science.gov (United States)

    Wan, Chunlei; Gu, Xiaokun; Dang, Feng; Itoh, Tomohiro; Wang, Yifeng; Sasaki, Hitoshi; Kondo, Mami; Koga, Kenji; Yabuki, Kazuhisa; Snyder, G Jeffrey; Yang, Ronggui; Koumoto, Kunihito

    2015-06-01

    Organic semiconductors are attracting increasing interest as flexible thermoelectric materials owing to material abundance, easy processing and low thermal conductivity. Although progress in p-type polymers and composites has been reported, their n-type counterpart has fallen behind owing to difficulties in n-type doping of organic semiconductors. Here, we present an approach to synthesize n-type flexible thermoelectric materials through a facile electrochemical intercalation method, fabricating a hybrid superlattice of alternating inorganic TiS2 monolayers and organic cations. Electrons were externally injected into the inorganic layers and then stabilized by organic cations, providing n-type carriers for current and energy transport. An electrical conductivity of 790 S cm(-1) and a power factor of 0.45 mW m(-1) K(-2) were obtained for a hybrid superlattice of TiS2/[(hexylammonium)x(H2O)y(DMSO)z], with an in-plane lattice thermal conductivity of 0.12 0.03 W m(-1) K(-1), which is two orders of magnitude smaller than the thermal conductivities of the single-layer and bulk TiS2. High power factor and low thermal conductivity contributed to a thermoelectric figure of merit, ZT, of 0.28 at 373 K, which might find application in wearable electronics. PMID:25849369

  18. Multi-layered organic light-emitting diode fabrication using low molecular weight materials by electrospray method

    International Nuclear Information System (INIS)

    Active technology development efforts to improve the productivity of organic light emitting diode (OLED) fabrication using wet processes based on ink-jet technology have been conducted by taking advantage of the low cost and large area processability of organic materials. However, OLEDs formed by conventional wet processes have been unable to reproduce the high performance levels of OLEDs that were mass-produced by dry processes based on vacuum deposition. We have therefore focused on the electrospray (ES) method as a potential fabrication technology. In this paper, we report on a multilayer thin-film fabrication process with low molecular-weight materials using an ES method that allows atomization of the organic materials by Coulomb repulsion and successive adhesion of solid-state multi-layered thin films. We demonstrate OLED fabrication by this ES method and the characteristics of the resulting devices. - Highlights: We fabricated multilayers of small organic molecules using electrospray (ES) method. ES method allows a film formation without erosion of the underlying organic layers. We evaluate the characteristics of OLEDs fabricated by ES method

  19. Multi-layered organic light-emitting diode fabrication using low molecular weight materials by electrospray method

    Energy Technology Data Exchange (ETDEWEB)

    Koishikawa, Yasushi; Miyazaki, Hiroshi [Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395 (Japan); Nippon Steel and Sumikin Chemical Co., Ltd., 46-80 Nakabaru Sakinohama, Tobata, Kitakyushu, Fukuoka 804-8503 (Japan); Yahiro, Masayuki [Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395 (Japan); Institute of Systems, Information Technologies and Nanotechnologies (ISIT), 2-1-22 Momochihama, Sawara, Fukuoka 814-0001 (Japan); Adachi, Chihaya, E-mail: adachi@cstf.kyushu-u.ac.jp [Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395 (Japan); International Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395 (Japan)

    2013-10-31

    Active technology development efforts to improve the productivity of organic light emitting diode (OLED) fabrication using wet processes based on ink-jet technology have been conducted by taking advantage of the low cost and large area processability of organic materials. However, OLEDs formed by conventional wet processes have been unable to reproduce the high performance levels of OLEDs that were mass-produced by dry processes based on vacuum deposition. We have therefore focused on the electrospray (ES) method as a potential fabrication technology. In this paper, we report on a multilayer thin-film fabrication process with low molecular-weight materials using an ES method that allows atomization of the organic materials by Coulomb repulsion and successive adhesion of solid-state multi-layered thin films. We demonstrate OLED fabrication by this ES method and the characteristics of the resulting devices. - Highlights: We fabricated multilayers of small organic molecules using electrospray (ES) method. ES method allows a film formation without erosion of the underlying organic layers. We evaluate the characteristics of OLEDs fabricated by ES method.

  20. Material identification in x-ray microscopy and micro CT using multi-layer, multi-color scintillation detectors.

    Science.gov (United States)

    Modgil, Dimple; Rigie, David S; Wang, Yuxin; Xiao, Xianghui; Vargas, Phillip A; La Rivire, Patrick J

    2015-10-21

    We demonstrate that a dual-layer, dual-color scintillator construct for microscopic CT, originally proposed to increase sensitivity in synchrotron imaging, can also be used to perform material quantification and classification when coupled with polychromatic illumination. We consider two different approaches to data handling: (1) a data-domain material decomposition whose estimation performance can be characterized by the Cramer-Rao lower bound formalism but which requires careful calibration and (2) an image-domain material classification approach that is more robust to calibration errors. The data-domain analysis indicates that useful levels of SNR (>5) could be achieved in one second or less at typical bending magnet fluxes for relatively large amounts of contrast (several mm path length, such as in a fluid flow experiment) and at typical undulator fluxes for small amount of contrast (tens of microns path length, such as an angiography experiment). The tools introduced could of course be used to study and optimize parameters for a wider range of potential applications. The image domain approach was analyzed in terms of its ability to distinguish different elemental stains by characterizing the angle between the lines traced out in a two-dimensional space of effective attenuation coefficient in the front and back layer images. This approach was implemented at a synchrotron and the results were consistent with simulation predictions. PMID:26422059

  1. Nanostructured layers of anion-defective gammaalumina New perspective TL and OSL materials for skin dosimetry. Preliminary results

    International Nuclear Information System (INIS)

    Thin- layer material based on nanostructured Al2O3 of the surface density 5mg/cm2 was obtained. The material is characterized by high OSL and TL yields comparable with those for TLD-500 which is one of the leaders among the TL and OSL detectors. The dose response, fading and dependence of TL yield on heating rate was studied. It is established that high luminescence yield of the samples under study correlates with the content of anion vacancies and ?-phase of Al2O3. The data for time-resolved luminescent spectroscopy are presented, which evidence for possible correlation between high TL and OSL activity and the F-type centers. It is noted that the material needs to be modified for successful use in dosimetry. In addition further studies to decrease the contribution of unstable (at 300K) components to OSL and TL yields are required. - Highlights: Thin nanostructured layers (TNL) of Al2O3 with thickness of 5mg/cm2 were obtained. Its TL and OSL yields are related to contents of ?-phase and anion vacancies. Dose response of TNL shows linear behavior in a range of 105000mGy. Luminescence properties of TNL are similar to such of anion-defective corundum. These properties are associated with centers of F-type

  2. De un sendero sacrificial surcado de goce // from a sacrificed path plow through of pleasure

    Directory of Open Access Journals (Sweden)

    Mario Orozco Guzmn

    2011-06-01

    Full Text Available El presente trabajo discierne un semblante maldito del sacrificio. En nombre del amor se ha idealizado el sacrificio como paradigma de su audacia y herosmo, mientras la cultura se ha encargado de enaltecer la proeza sacrificial como puesta en acto del amor. El destinatario de esta inmolacin suprema inscribe la produccin del goce divino en calidad de objeto a, tal como lo revelan sacrificios paradigmticos presentes en la historia y la literatura. // The current work discerns a cursed countenance from the sacrifice. The sacrifice has been idealized in love's name, as paradigm of its courage and heroism, meanwhile the culture has taken charge of dignifying the sacrificed feat as event in the love act. The addressee of this supreme immolation registers the production of the divine enjoyment as a object, just as it is revealed by paradigmatic sacrifices present on history and literature.

  3. Sacrificial limbs of sovereignty: disabled veterans, masculinity, and nationalist politics in Turkey.

    Science.gov (United States)

    Aiksz, Salih Can

    2012-03-01

    Over the last decade, disabled veterans of the Turkish Army who were injured while fighting against the Partiya Karkern Kurdistan (PKK; Kurdistan Workers' Party) have become national icons and leading ultranationalist actors. While being valorized as sacrificial heroes in nationalist discourse, they have also confronted socioeconomic marginalization, corporeal otherness, and emasculation anxieties. Against this backdrop, disabled veterans' organizations have become the locus of an ultranationalist campaign against dissident intellectuals. Building on two years of ethnographic research with disabled veterans in Turkey, this article analyzes these processes through the analytical lens of the body. Locating the disabled veteran body at the intersection of state welfare practices, nationalist discourses on heroism and sacrifice, and cultural norms of masculinity and disability, I illustrate how disabled veterans' gendered and classed experiences of disability are hardened into a political identity. Consequently, I show how violence generates new modalities of masculinity and political agency through its corporeal effects. PMID:22574389

  4. Cathodic protection by zinc sacrificial anodes: impact on marine sediment metallic contamination.

    Science.gov (United States)

    Rousseau, C; Baraud, F; Leleyter, L; Gil, O

    2009-08-15

    Cathodic protection by sacrificial zinc anodes is often applied to prevent immerged metallic structures from corrosion. But this technique induces the zinc anodes dissolution, which can induce marine sediments and seawater contamination. A large scale experiment, in natural seawater, was conducted during 12 months, in order to evaluate the potential environmental impact of this continuous zinc dissolution, and of some necessary cleaning operations of the anodes surfaces. The heavy metal (Cr, Cu, Pb and Zn) concentration in water and sediment samples was monitored. A sequential extraction procedure was applied on sediment samples to differentiate the zinc mobile fractions from the residual one. A significant increase of zinc concentration was observed in water as well as in the surface sediments under the specific operating conditions. Sediments then become a secondary pollution source, as the sorbed labile zinc can be remobilized to seawater. PMID:19250740

  5. New efficient electrochemical synthesis of 1,5-dithioxylopyranosides in the presence of a sacrificial anode.

    Science.gov (United States)

    Brevet, David; Mugnier, Yves; Samreth, Soth; Dellis, Philippe

    2003-07-22

    Electroreduction of the disulfide derivative RSSR (5, R= [bond]C(6)H(4)[bond]CO[bond]C(6)H(4)[bond]CN) on a mercury pool or a carbon gauze electrode in the presence of 2,3,4-tri-O-acetyl-5-thio-D-xylopyranosyl bromide (1), using a sacrificial zinc anode gave an alpha,beta anomeric mixture of [4-(4-cyanobenzoylphenyl)] 2,3,4-tri-O-acetyl-1,5-dithio-D-xylopyranoside (6) in 40-70% yield, according to the experimental conditions used (nature of solvent, electrolyte salt, and temperature). High selectivity favouring the alpha anomer of 6 is observed starting from the alpha anomer of 1. Mechanistic aspects are discussed. PMID:12860425

  6. Preliminary Study on Piezoresistive and Piezoelectric Properties of a Double-layer Soft Material for Tactile Sensing

    Directory of Open Access Journals (Sweden)

    Weiting LIU

    2015-07-01

    Full Text Available This paper describes a double-layer simplified sensor unit with interesting electromechanical properties, which consists of a film made from multiwalled carbon nanotube (MWNT mixed by polymer composite and a thin film of polyvinylidene fluoride (PVDF. It is envisaged to imitate the distributed tactile receptors of human hands so as to help the disabled to recover the basic tactile perception. This paper shows the fabrication and performance research of such a new piezoelectric-piezoresistive composite material, which indicates a promising application in prosthetic hand.

  7. Study of surfaces and surface layers on high temperature materials after short-time thermal loads

    International Nuclear Information System (INIS)

    Being part of the plasma-wall interaction during TOKAMAK operation, erosion- and redeposition processes of First Wall materials substantially influence plasma parameters as well as the properties of the First Wall. An important redeposition process of eroded material is the formation of thin films by atomic condensation. Examinations of First Wall components after TOKAMAK operation lead to the assumption that these thin metallic films tend to agglomerate to small particles under subsequent heat load. In laboratory experiments it is shown that thin metallic films on various substrates can agglomerate under short time high heat fluxes and also under longer lasting lower thermal loads, thus verifying the ''agglomeration hypothesis''. (orig.)

  8. Localized corrosion of metallic materials and ? radiation effects in passive layers under simulated radwaste repository conditions. Final report

    International Nuclear Information System (INIS)

    The task of the project was to simulate the conditions in a radwaste repository and to perform local analyses in order to detect the critical conditions and material susceptibilities leading to localized corrosion of materials. The information thus obtained was to yield more precise data on the long-term stability of materials for the intended purpose, in order to be able to appropriately select or optimize the materials (Ti, TiO.2Pd, Hastelloy C4, fine-grained structural steel). A major aspect to be examined was natural inhomogeneities of the electrode surfaces, as determined by the grain structure of the selected materials. Thus a laterally inhomogeneous composition in the welded zone induces an inhomogeneous current distribution, and hence strong susceptibility to localized corrosion. This effect was to be quantified, and the localized corrosion processes had to be identified by means of novel, electrochemical methods with a resolution power of ?m. The investigations were to be made under conditions as near to practice as possible, for instance by simulating radwaste repository conditions and performing measurements at elevated temperatures (170 C) in an autoclave. Another task was to examine the radiation effects of ? radiation on passive layers, and describe the possible modifications induced by recrystallisation, photocorrosion, or oxide formation. (orig./MM)

  9. The impact of porosity on the formation of manganese based copper diffusion barrier layers on low-? dielectric materials

    Science.gov (United States)

    McCoy, A. P.; Bogan, J.; Walsh, L.; Byrne, C.; O'Connor, R.; Woicik, J. C.; Hughes, G.

    2015-08-01

    This work investigates the impact of porosity in low-? dielectric materials on the chemical and structural properties of deposited Mn thin films for copper diffusion barrier layer applications. X-ray photoelectron spectrscopy (XPS) results highlight the difficulty in distinguishing between the various Mn oxidation states which form at the interlayer dielectric (ILD)/Mn interface. The presence of MnSiO3 and MnO were identified using x-ray absorption spectroscopy (XAS) measurements on both porous and non-porous dielectric materials with evidence of Mn2O3 and Mn3O4 in the deposited film on the latter surface. It is shown that a higher proportion of deposited Mn converts to Mn silicate on an ILD film which has 50% porosity compared with the same dielectric material with no porosity, which is attributed to an enhanced chemical interaction with the effective larger surface area of porous dielectric materials. Transmission electron microscopy (TEM) and energy-dispersive x-ray spectroscopy (EDX) data shows that the Mn overlayer remains predominately surface localised on both porous and non-porous materials.

  10. Features in Energy Accumulation in Double Layer on the surface of Graphene Material

    CERN Document Server

    Kompan, Mikhail Evgenievich; Maslov, Alexander Yurievich; Kuznetsov, Viktor Petrovich; Krivchenko, Viktor Aleksandrovich

    2015-01-01

    An application of quantum size carbon structures--graphenes as electrodes of supercapacitors is studied. A fundamental limit of energy and power density arising from quantum nature of objects due to singularity in graphene density of states near Dirac point is determined and technical solutions to partially offset the negative factors are considered. The maximum possible specific capacitance of nanostructured electrode materials is determined.

  11. Processing of brittle materials in the nanometer range of thickness of layers cut

    Science.gov (United States)

    Shavva, M. A.; Lapshin, V. V.; Grubyy, S. V.

    2015-09-01

    The article deals with the results of experimental research in the ultra-precision diamond machining of brittle materials - potassium dihydrogen phosphate, single-crystal quartz, quartz glass, crystalline glass, sapphire, and germanium. The processing modes at which the nanometer roughness of the processed surface was achieved are specified.

  12. Comparative study on electrical properties of atomic layer deposited high-permittivity materials on silicon substrates

    International Nuclear Information System (INIS)

    Deep level transient spectroscopy, capacitance-voltage and conductance transient measurement techniques have been applied in order to evaluate the electrical quality of thin high-permittivity oxide layers on silicon. The oxides studied included HfO2 film grown from two different oxygen-free metal precursors and Ta2O5 and Nb2O5 nanolaminates. The interface trap densities correlated to the oxide growth chemistry and semiconductor substrate treatment. No gap state densities induced by structural disorder were measured in the films grown on chemical SiO2. Trap densities were also clearly lower in HfO2 films compared to Ta2O5-Nb2O5

  13. Multifunctional-layered materials for creating membrane-restricted nanodomains and nanoscale imaging

    Science.gov (United States)

    Srinivasan, P.

    2016-01-01

    Experimental platform that allows precise spatial positioning of biomolecules with an exquisite control at nanometer length scales is a valuable tool to study the molecular mechanisms of membrane bound signaling. Using micromachined thin film gold (Au) in layered architecture, it is possible to add both optical and biochemical functionalities in in vitro. Towards this goal, here, I show that docking of complementary DNA tethered giant phospholiposomes on Au surface can create membrane-restricted nanodomains. These nanodomains are critical features to dissect molecular choreography of membrane signaling complexes. The excited surface plasmon resonance modes of Au allow label-free imaging at diffraction-limited resolution of stably docked DNA tethered phospholiposomes, and lipid-detergent bicelle structures. Such multifunctional building block enables realizing rigorously controlled in vitro set-up to model membrane anchored biological signaling, besides serving as an optical tool for nanoscale imaging.

  14. The effect of fibre layering pattern in resisting bending loads of natural fibre-based hybrid composite materials

    Directory of Open Access Journals (Sweden)

    Jusoh Muhamad Shahirul Mat

    2016-01-01

    Full Text Available The effect of fibre layering pattern and hybridization on the flexural properties of composite hybrid laminates between natural fibres of basalt, jute and flax with synthetic fibre of E-glass reinforced epoxy have been investigated experimentally. Results showed that the effect fibre layering pattern was highly significant on the flexural strength and modulus, which were strongly dependent on the hybrid configuration between sandwich-like (SL and intercalation (IC sequence of fibre layers. In addition, specific modulus based on the variation densities of the hybrid laminates was used to discover the best combination either basalt, jute or flax with E-glass exhibits superior properties concerning on the strength to weight-ratio. Generally, SL sequence of glass/basalt exhibited superior strength and stiffness compared with glass/jute and glass/flax in resisting bending loads. In terms of hybridization effect, glass/jute was found to be the best combination with E-glass compared to the rest of natural fibres investigated in the present study. Hence, the proper stacking sequences and material selection are among predominant factors that influence on mechanical properties and very crucial in designing composite hybrid system to meet the desired requirements.

  15. A functionalized phosphonate-rich organosilica layered hybrid material (PSLM) fabricated through a mild process for heavy metal uptake

    Energy Technology Data Exchange (ETDEWEB)

    Daikopoulos, Chris [Department of Materials Science and Engineering, University of Ioannina, Ioannina 45110 (Greece); Bourlinos, Athanasios B. [Institute of Materials Science, NCSR Demokritos, Ag. Paraskevi Attikis, Athens 15310 (Greece); Georgiou, Yiannis [Laboratory of Physical Chemistry, Department of Environmental and Natural Resources Management, University of Patras, Seferi 2, Agrinio 30100 (Greece); Deligiannakis, Yiannis, E-mail: ideligia@cc.uoi.gr [Laboratory of Physical Chemistry, Department of Environmental and Natural Resources Management, University of Patras, Seferi 2, Agrinio 30100 (Greece); Zboril, Radek [Regional Centre of Advanced Technologies and Materials, Faculty of Science, Department of Physical Chemistry and Experimental Physics, Palacky University, Olomouc 77146 (Czech Republic); Karakassides, Michael A. [Department of Materials Science and Engineering, University of Ioannina, Ioannina 45110 (Greece)

    2014-04-01

    Highlights: Novel phosphonate-rich organosilica layered hybrid material (PSLM) fabricated through a mild xerogel process. Surface Complexation Modeling reveals that PSLM bears 2 types of functional groups able to bind heavy metal. Maximum metal uptake capacities were found 2.72 mmol g{sup ?1} for Cu{sup 2+}, 1.67 mmol g{sup ?1} for Pb{sup 2+} and 1.00 mmol g{sup ?1} for Cd{sup 2+} at pH 7. EPR spectroscopy reveals local coordination environment for Cu{sup 2+} ions. - Abstract: A phosphonate-rich organosilica layered hybrid material (PSLM) made of 3-(trihydroxysilyl)propyl methylphosphonate, monosodium salt, as the single silica source, has been obtained from its aqueous solution through a xerogel process and mild thermal aging. The method is simple, affording bulk quantities of powdered PSLM in a single-step. The hybrid is stable in water and possesses a high content of phosphonate groups fixed on the solid matrix. In addition, PSLM shows good thermal stability, which exceeds 300 C in air. The material was characterized using SEM, TEM, XRD, FT-IR and TGA techniques. Potentiometric titrations show that PSLM bears high-surface density of phosphonate groups (3 mmol g{sup ?1}). As a result, the material displays high metal uptake capacity for heavy metal ions such as Cu{sup 2+} (2.72 mmol g{sup ?1}), Pb{sup 2+} (1.67 mmol g{sup ?1}) and Cd{sup 2+} (1.00 mmol g{sup ?1}) at neutral pH values e.g. the pH of natural waters. Detailed theoretical modeling using a Surface Complexation Model combined with Electron Paramagnetic Resonance (EPR) spectroscopy shows that the surface distribution of surface bound Cu{sup 2+} ions is rather homogeneous e.g. copper-binding phosphonate sites are arranged in average distances 58 ?.

  16. A novel class of strain gauges based on layered percolative films of 2D materials.

    Science.gov (United States)

    Hempel, Marek; Nezich, Daniel; Kong, Jing; Hofmann, Mario

    2012-11-14

    Here we report on the fabrication and characterization of a novel type of strain gauge based on percolative networks of 2D materials. The high sensitivity of the percolative carrier transport to strain induced morphology changes was exploited in strain sensors that can be produced from a wide variety of materials. Highly reliable and sensitive graphene-based thin film strain gauges were produced from solution processed graphene flakes by spray deposition. Control of the gauge sensitivity could be exerted through deposition-induced changes to the film morphology. This exceptional property was explained through modeling of the strain induced changes to the flake-flake overlap for different percolation networks. The ability to directly deposit strain gauges on complex-shaped and transparent surfaces was presented. The demonstrated scalable fabrication, superior sensitivity over conventional sensors, and unique properties of the described strain gauges have the potential to improve existing technology and open up new fields of applications for strain sensors. PMID:23045955

  17. Development of photocatalytic ceramic materials through the deposition of TiO2 nanoparticles layers

    OpenAIRE

    Carneiro, Joaquim A. O.; Teixeira, Vasco M. P.; Azevedo, Sofia; Fernandes, Filipa; Neves, Jorge

    2012-01-01

    Urbanism and communities centralization enlarges atmospheric pollution that affects both human beings as well as their constructed buildings. Different scientific and technological studies are being conducted, both in academic and construction industry, aiming the development of new construction materials with properties that can decrease visual pollution of cities, reducing also the number of cleanings required. The present research work aims the study and the production of self-cleaning ...

  18. A green synthesis of a layered titanate, potassium lithium titanate; lower temperature solid-state reaction and improved materials performance

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, Makoto, E-mail: waseda.ogawa@gmail.com [Graduate School of Creative Science and Engineering, Waseda University, 1-6-1 Nishiwaseda, Shinjuku-ku, Tokyo 169-8050 (Japan); Department of Earth Sciences, Waseda University, 1-6-1 Nishiwaseda, Shinjuku-ku, Tokyo 169-8050 (Japan); Morita, Masashi, E-mail: m-masashi@y.akane.waseda.jp [Graduate School of Creative Science and Engineering, Waseda University, 1-6-1 Nishiwaseda, Shinjuku-ku, Tokyo 169-8050 (Japan); Igarashi, Shota, E-mail: uxei_yoshi_yoshi@yahoo.co.jp [Graduate School of Creative Science and Engineering, Waseda University, 1-6-1 Nishiwaseda, Shinjuku-ku, Tokyo 169-8050 (Japan); Sato, Soh, E-mail: rookie_so_sleepy@yahoo.co.jp [Graduate School of Creative Science and Engineering, Waseda University, 1-6-1 Nishiwaseda, Shinjuku-ku, Tokyo 169-8050 (Japan)

    2013-10-15

    A layered titanate, potassium lithium titanate, with the size range from 0.1 to 30 m was prepared to show the effects of the particle size on the materials performance. The potassium lithium titanate was prepared by solid-state reaction as reported previously, where the reaction temperature was varied. The reported temperature for the titanate preparation was higher than 800 C, though 600 C is good enough to obtain single-phase potassium lithium titanate. The lower temperature synthesis is cost effective and the product exhibit better performance as photocatalysts due to surface reactivity. - Graphical abstract: Finite particle of a layered titanate, potassium lithium titanate, was prepared by solid-state reaction at lower temperature to show modified materials performance. Display Omitted - Highlights: Potassium lithium titanate was prepared by solid-state reaction. Lower temperature reaction resulted in smaller sized particles of titanate. 600 C was good enough to obtain single phased potassium lithium titanate. The product exhibited better performance as photocatalyst.

  19. Determining the humidity profiles in thick layers of building materials by means of prompt gamma neutron activation analysis

    International Nuclear Information System (INIS)

    A new non-destructive and quantitative test method for determining the humidity profiles of thick layers (0.2-0.8 m) of building materials and structures is proposed. The method is based on spectrometric detection of hard prompt gamma rays (2.23 MeV) from the absorption of thermalised fast neutrons in hydrogen nuclei. For scanning the object, e.g.: A thick layer made of concrete or bricks etc. in the X, Y direction, one uses a collimated bundle of fast neutrons (14 MeV) from a mobile neutron generator. The humidity profile is determined by gamma spectrometer scanning of the prompt gamma source density along the optical path of the neutron bundle in the object, by means of a gas spectrometer equipped with a collimator (ID tomography). The method makes the simultaneous detection of different nests of salts and structural materials, e.g. steel bars, copper or aluminium plates, possible. Based on the transport properties of the neutrons and the properties of the PGNAA method, the characteristic properties and experimental possibilities of the proposed method are described. The plans for researching and developing the method and the adaptation of the measuring apparatus are explained. (orig./HP)

  20. Phenylvinyl-Substituted Carbazole Twin Compounds as Efficient Materials for the Charge-Transporting Layers of OLED Devices

    Science.gov (United States)

    Tavgeniene, D.; Liu, L.; Krucaite, G.; Volyniuk, D.; Grazulevicius, J. V.; Xie, Z.; Zhang, B.; Grigalevicius, S.

    2015-10-01

    Twin compounds containing two phenylvinyl-substituted carbazole rings were synthesized by multi-step synthesis. The compounds were characterized by thermogravimetric analysis, differential scanning calorimetry, and electron photoemission spectroscopy. The thermal stability of the materials was very high; initial thermal degradation temperatures were in the range 411-419C. The glass-transition temperatures of the amorphous materials were in the range 74-119C. Electron photoemission spectra of thin layers of the compounds revealed ionization potentials were in the range 5.05-5.45 eV. The hole-transporting properties of thin amorphous layers of the twin compounds were tested in organic light-emitting diodes with Alq3 as green emitter. The best overall performance was observed for a device based on the twin compound containing 3-[2-(4-methylphenyl)vinyl]carbazole groups; the turn-on voltage was 2.6 V, the maximum photometric efficiency 2.34 cd/A, and maximum brightness approximately 7380 cd/m2. At a brightness of 1000 cd/m2 the photometric efficiency was 23% higher than for a PEDOT:PSS-based device.

  1. Imaging of phase change materials below a capping layer using correlative infrared near-field microscopy and electron microscopy

    Science.gov (United States)

    Lewin, M.; Hauer, B.; Bornhfft, M.; Jung, L.; Benke, J.; Michel, A.-K. U.; Mayer, J.; Wuttig, M.; Taubner, T.

    2015-10-01

    Phase Change Materials (PCM) show two stable states in the solid phase with significantly different optical and electronic properties. They can be switched reversibly between those two states and are promising candidates for future non-volatile memory applications. The development of phase change devices demands characterization tools, yielding information about the switching process at high spatial resolution. Scattering-type Scanning Near-field Optical Microscopy (s-SNOM) allows for spectroscopic analyses of the different optical properties of the PCMs on the nm-scale. By correlating the optical s-SNOM images with transmission electron microscopy images of the same sample, we unambiguously demonstrate the correlation of the infrared optical contrast with the structural state of the phase change material. The investigated sample consists of sandwiched amorphous and crystalline regions of Ag 4 In 3 Sb 67 Te 26 below a 100 nm thick ( ZnS ) 80 - ( SiO2 ) 20 capping layer. Our results demonstrate the sensitivity of s-SNOM to small dielectric near-field contrasts even below a comparably thick capping layer ( 100 nm ).

  2. A green synthesis of a layered titanate, potassium lithium titanate; lower temperature solid-state reaction and improved materials performance

    International Nuclear Information System (INIS)

    A layered titanate, potassium lithium titanate, with the size range from 0.1 to 30 m was prepared to show the effects of the particle size on the materials performance. The potassium lithium titanate was prepared by solid-state reaction as reported previously, where the reaction temperature was varied. The reported temperature for the titanate preparation was higher than 800 C, though 600 C is good enough to obtain single-phase potassium lithium titanate. The lower temperature synthesis is cost effective and the product exhibit better performance as photocatalysts due to surface reactivity. - Graphical abstract: Finite particle of a layered titanate, potassium lithium titanate, was prepared by solid-state reaction at lower temperature to show modified materials performance. Display Omitted - Highlights: Potassium lithium titanate was prepared by solid-state reaction. Lower temperature reaction resulted in smaller sized particles of titanate. 600 C was good enough to obtain single phased potassium lithium titanate. The product exhibited better performance as photocatalyst

  3. Positron annihilation lifetime spectroscopy (PALS) application in metal barrier layer integrity for porous low- k materials

    CERN Document Server

    Simon, Lin; Gidley, D W; Wetzel, J T; Monnig, K A; Ryan, E T; Simon, Jang; Douglas, Yu; Liang, M S; En, W G; Jones, E C; Sturm, J C; Chan, M J; Tiwari, S C; Hirose, M

    2002-01-01

    Positron Annihilation Lifetime Spectroscopy (PALS) is a useful tool to pre-screen metal barrier integrity for Si-based porous low-k dielectrics. Pore size of low-k, thickness of metal barrier Ta, positronium (Ps) leakage from PALS, trench sidewall morphology, electrical test from one level metal (1LM) pattern wafer and Cu diffusion analysis were all correlated. Macro-porous low-k (pore size >=200 AA) and large scale meso-porous low-k (>50~200 AA) encounter both Ps leakage and Cu diffusion into low-k dielectric in the 0.25 mu mL/0.3 mu mS structures when using SEMATECH in-house PVD Ta 250 AA as barrier layer. For small scale meso-porous (>20~50 AA) and micro- porous (<=20 AA) low-k, no Ps leakage and no Cu diffusion into low-k were observed even with PVD Ta 50 AA, which is proved also owing to sidewall densification to seal all sidewall pores due to plasma etch and ash. For future technology, smaller pore size of porous Si-based low-k (=<50 AA) will be preferential for dense low-k like trench sidewall to...

  4. Impact of Carbon and Tungsten as Divertor Materials on the Scrape-off Layer Conditions in JET

    International Nuclear Information System (INIS)

    Full text: In detached divertor conditions, a five-fold stronger reduction of the ion current to the low-field side target plate and a 30% increase in the density limit were observed in neutral-beam heated, low-confinement mode plasmas with the ITER-like Wall compared to the previous carbon wall. These significant differences occurred at higher core densities despite the fact that nearly identical scrape-off layer parameters were measured in attached divertor conditions. When attached, the magnitude and distribution of radiative power as well as the total ion currents to the divertor target plates were measured the same for a range of divertor plasma geometries, including configurations with the high field side strike point on the vertical plate and the low field side strike point on the horizontal plate, and configurations with both strike points on the vertical plates. The 5-to-10-fold reduction of the scrape-off layer carbon content as inferred from low charge state carbon emission, and the fact that both beryllium and tungsten have a low radiation potential in the scrape-off layer, would indicate that the deuterium emission was and still is the dominating radiator. Simulations of deuterium gas fuelling scans with the fluid edge code EDGE2/EIRENE show that replacing carbon with beryllium and tungsten as wall materials leads to reduced impurity radiation, as expected, and translates into an increase in the power conducted to the plates. The ion currents to the plates, however, are predicted to be similar in both materials configurations. Saturation of the ion currents is predicted at the highest achievable density; the simulations do not predict the reduction of the currents close to the density limit as observed in the experiments. Since the JET ITER-like wall constitutes the same materials and their poloidal distribution as foreseen for the nuclear phase of ITER, understanding the observed differences in the SOL conditions between the two materials configuration, and clarifying the discrepancy between the experimental data and simulations are instrumental for erosion and power handling in ITER. (author)

  5. Gate-tunable diode and photovoltaic effect in an organic-2D layered material p-n junction

    Science.gov (United States)

    Vlez, Sal; Ciudad, David; Island, Joshua; Buscema, Michele; Txoperena, Oihana; Parui, Subir; Steele, Gary A.; Casanova, Flix; van der Zant, Herre S. J.; Castellanos-Gomez, Andres; Hueso, Luis E.

    2015-09-01

    The semiconducting p-n junction is a simple device structure with great relevance for electronic and optoelectronic applications. The successful integration of low-dimensional materials in electronic circuits has opened the way forward for producing gate-tunable p-n junctions. In that context, we present here an organic (Cu-phthalocyanine)-2D layered material (MoS2) hybrid p-n junction with both gate-tunable diode characteristics and photovoltaic effect. Our proof-of-principle devices show multifunctional properties with diode rectifying factors of up to 104, while under light exposure they exhibit photoresponse with a measured external quantum efficiency of ~11%. As for their photovoltaic properties, we found open circuit voltages of up to 0.6 V and optical-to-electrical power conversion efficiency of 0.7%. The extended catalogue of known organic semiconductors and two-dimensional materials offer the prospect for tailoring the properties and the performance of the resulting devices, making organic-2D p-n junctions promising candidates for future technological applications.The semiconducting p-n junction is a simple device structure with great relevance for electronic and optoelectronic applications. The successful integration of low-dimensional materials in electronic circuits has opened the way forward for producing gate-tunable p-n junctions. In that context, we present here an organic (Cu-phthalocyanine)-2D layered material (MoS2) hybrid p-n junction with both gate-tunable diode characteristics and photovoltaic effect. Our proof-of-principle devices show multifunctional properties with diode rectifying factors of up to 104, while under light exposure they exhibit photoresponse with a measured external quantum efficiency of ~11%. As for their photovoltaic properties, we found open circuit voltages of up to 0.6 V and optical-to-electrical power conversion efficiency of 0.7%. The extended catalogue of known organic semiconductors and two-dimensional materials offer the prospect for tailoring the properties and the performance of the resulting devices, making organic-2D p-n junctions promising candidates for future technological applications. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr04083c

  6. The Effect of the Thickness of the Low Temperature AlN Nucleation Layer on the Material Properties of GaN Grown on a Double-Step AlN Buffer Layer by the MOCVD Method

    Science.gov (United States)

    Huang, Wei-Ching; Chu, Chung-Ming; Hsieh, Chi-Feng; Wong, Yuen-Yee; Chen, Kai-wei; Lee, Wei-I.; Tu, Yung-Yi; Chang, Edward-Yi; Dee, Chang Fu; Majlis, B. Y.; Yap, S. L.

    2016-02-01

    The influence of low-temperature AlN (LT-AlN) nucleation layer thickness on the material properties of the GaN layer grown on the double-step AlN layer is investigated. When GaN was grown without the LT-AlN nucleation layer, the GaN layer has low sheet resistance of 464 ohm/sq and the surface was decorated with pitted region. On the other hand, when a LT-AlN layer with a thickness of 5 nm was inserted, a GaN layer with sheet resistance higher than 106 ohm/sq was achieved. This thin nucleation layer also improved the GaN morphology, suppressed inversion domain formation, and reduced oxygen impurity incorporation. However, the surface morphology and quality of the GaN crystal were severely degraded when the LT-AlN thickness was increased to 10 nm due to the formation of disorientated grains in the LT-AlN layer.

  7. Measurement method for high-temperature infrared optical constants of ZnS crystal materials in a multi-layer structure

    Science.gov (United States)

    Fu, Tairan; Liu, Jiangfan

    2015-03-01

    An inverse method was used to calculate the optical constants of high-temperature semi-transparent materials in the infrared spectra based on the angle dependent transmittances of multi-layer structure. The radiative transfer model for the multi-layer semi-transparent structure was established. A three-layer structure composed by zinc sulfide (ZnS) infrared optical materials was investigated with a numerical analysis of the radiation characteristics to analyze the effects of the two side layers (defined as optical windows) on the radiation properties of the three-layer structure. The inverse calculations of the optical constants of ZnS materials were carried out based on the total transmittances of the three-layer structure at different incidence angles using the Levenberg-Marquardt algorithm. The inverse accuracy for the optical constants was numerically verified. This research works provides a reference for measurements of high-temperature radiation properties of semi-transparent materials in multi-layer structure.

  8. Investigation into the manufacturing of female blanking dies made of multi-layers of steel and superplastic Materials

    International Nuclear Information System (INIS)

    Superplasticity is a feature which means the ability of deforming up to large strains at relatively low stresses when the material is deformed under certain condition of temperature and strain rate. This superplastic characteristic of metals and alloys is invested in manufacturing parts mainly used in the automobile industry. Superplastic tin-lead eutectic alloy is usually used for the laboratory investigations due to its low melting point, high ductility, and very low strength. In this paper, the utilization of superplastic tin-lead alloy is used to investigate the possibility of manufacturing female blanking dies. These dies are mainly machined with loss of materials with time consuming and high cost particularly in case of complicated and intricate shapes of dies. The idea was brought about from a previous work of one of the authors on the blanking of this superplastic materials where the best quality blanks (i.e. minimum dishing, doming and edge taper) of the blanks at zero radial clearance percentage. Hence, the pierced sheet will have the same dimensions and details of the punch. Multi layered plate made of alternative laminates of steel and tin-lead superplastic material joined at their interfaces by an adhesive material of high shear strength, araldite, were used in producing the female dies, by piercing the plate by a punch of the required shape. Three different shapes of blanking dies were produced the details of the punches appeared clearly in the pierced plate. This newly reported method has the following advantages, high accuracy is achieved, low force and energy are required for production of the dies, and hence low production cost. (author)

  9. Characterization of dielectric materials in thin layers for the development of S.O.I. (Silicon on Insulator) substrates

    International Nuclear Information System (INIS)

    This thesis deals with the characterization of oxide layer placed inside S.O.I. substrates and submitted to irradiation. This type of material is used for the development of hardened electronic components, that is to say components able to be used in a radiative environment. The irradiation induces charges (electrons or holes) in the recovered oxide. A part of these charges is trapped which leads to changes of the characteristics of the electronic components made on these substrates. The main topic of this study is the characterization of trapping properties of recovered oxides and more particularly of 'Unibond' material carried out with a new fabrication process: the 'smart-cut' process. This work is divided into three parts: - study with one carrier: this case is limited to low radiation doses where is only observed holes trapping. The evolution of the physical and chemical properties of the 'Unibond' material recovered oxide has been revealed, this evolution being due to the fabrication process. - Study with two carriers: in this case, there is trapping of holes and electrons. This type of trapping is observed in the case of strong radiation doses. A new type of electrons traps has been identified with the 'Unibond' material oxide. The transport and the trapping of holes and electrons have been studied in the case of transient phenomena created by short radiative pulses. This study has been carried out using a new measurement method. - Study with three carriers: here are added to holes and electrons the protons introduced in the recovered oxide by the annealing under hydrogen. These protons are movable when they are submitted to the effect of an electric field and they induce a memory effect according to their position in the oxide. These different works show that the 'Unibond' material is a very good solution for the future development of S.O.I. (author)

  10. Controllable synthesis of graphene sheets with different numbers of layers and effect of the number of graphene layers on the specific capacity of anode material in lithium-ion batteries

    International Nuclear Information System (INIS)

    High quality graphene sheets are synthesized through efficient oxidation process followed by rapid thermal expansion and reduction by H2. The number of graphene layers is controlled by tuning the oxidation degree of GOs. The higher the oxidation degree of GOs is getting, the fewer the numbers of graphene layers can be obtained. The material is characterized by elemental analysis, thermo-gravimetric analysis, scanning electron microscopy, atomic force microscopy, transmission electron microscopy and Fourier transform infrared spectroscopies. The obtained graphene sheets with single, triple and quintuplicate layers as anode materials exhibit a high reversible capacity of 1175, 1007, and 842 mA h g-1, respectively, which show that the graphene sheets with fewer layers have higher reversible capacity. -- Graphical abstract: The typical TEM images of the graphene sheets derived from GO3(a), GO2(b) and GO1(c). Display Omitted Highlights: ? With the oxidation degree of GO increasing, the numbers of graphene layers decreased. ? With the numbers of graphene layers decreasing, the reversible capacity improved. ? Graphene sheets with single-layer exhibit the best electrochemical performances.

  11. Nano-sized structured layered positive electrode materials to enable high energy density and high rate capability lithium batteries

    Science.gov (United States)

    Deng, Haixia; Belharouak, Ilias; Amine, Khalil

    2012-10-02

    Nano-sized structured dense and spherical layered positive active materials provide high energy density and high rate capability electrodes in lithium-ion batteries. Such materials are spherical second particles made from agglomerated primary particles that are Li.sub.1+.alpha.(Ni.sub.xCo.sub.yMn.sub.z).sub.1-tM.sub.tO.sub.2-dR.sub.d- , where M is selected from can be Al, Mg, Fe, Cu, Zn, Cr, Ag, Ca, Na, K, In, Ga, Ge, V, Mo, Nb, Si, Ti, Zr, or a mixture of any two or more thereof, R is selected from F, Cl, Br, I, H, S, N, or a mixture of any two or more thereof, and 0.ltoreq..alpha..ltoreq.0.50; 0materials and their use in electrochemical devices are also described.

  12. Sensitivity study of multi-layer active magnetic regenerators using first order magnetocaloric material La(Fe,Mn,Si)13Hy

    Science.gov (United States)

    Lei, Tian; Nielsen, Kaspar K.; Engelbrecht, Kurt; Bahl, Christian R. H.; Neves Bez, Henrique; Veje, Christian T.

    2015-07-01

    We present simulation results of multi-layer active magnetic regenerators using the solid-state refrigerant La(Fe,Mn,Si)13Hy. This material presents a large, however quite sharp, isothermal entropy change that requires a careful choice of number of layers and working temperature for multi-layer regenerators. The impact of the number of layers and the sensitivity to the working temperature as well as the temperature span are quantified using a one dimensional numerical model. A study of the sensitivity of variation in Curie temperature through a uniform and normal distribution is also presented. The results show that the nominal cooling power is very sensitive to the Curie temperature variation in the multi-layer regenerators. A standard deviation of the Curie temperature variation for a normal distribution less than 0.6 K is suggested in order to achieve sufficient performance of a 15-layer regenerator with Curie temperature spacing of 2 K.

  13. Sensitivity study of multi-layer active magnetic regenerators using first order magnetocaloric material La(Fe,Mn,Si)13Hy

    DEFF Research Database (Denmark)

    Lei, Tian; Nielsen, Kaspar Kirstein

    2015-01-01

    We present simulation results of multi-layer active magnetic regenerators using the solid-state refrigerant La(Fe,Mn,Si)13Hy. This material presents a large, however quite sharp, isothermal entropy change that requires a careful choice of number of layers and working temperature for multi-layer regenerators. The impact of the number of layers and the sensitivity to the working temperature as well as the temperature span are quantified using a one dimensional numerical model. A study of the sensitivity of variation in Curie temperature through a uniform and normal distribution is also presented. The results show that the nominal cooling power is very sensitive to the Curie temperature variation in the multi-layer regenerators. A standard deviation of the Curie temperature variation for a normal distribution less than 0.6 K is suggested in order to achieve sufficient performance of a 15-layer regenerator with Curie temperature spacing of 2 K.

  14. Influence of fouling on the efficiency of sacrificial anodes in providing cathodic protection in Southeast Asian tropical seawater.

    Science.gov (United States)

    Blackwood, D J; Lim, C S; Teo, S L M

    2010-10-01

    Aluminum and zinc based sacrificial anodes are routinely used to provide corrosion protection to metals (typically steel) exposed to seawater, for example in steel pipelines and storage tanks. However, the high fouling rates experienced in South East Asia means that both the anodes and the metals to be protected rapidly become coated with macrofoulers, which could potentially prevent the anodes from being effective. The present study, involving exposure tests of up to 18 months, indicates that both aluminum and zinc sacrificial anodes remain effective even after being completely coated with biofouling. Furthermore, it was easier to remove the biofouling on the cathodically protected samples than on their unprotected counterparts, possibly due to the higher local pH produced by cathodic protection at the metal and seawater interface. PMID:20818571

  15. Growth of type II strained layer superlattice, bulk InAs and GaSb materials for minority lifetime characterization

    Science.gov (United States)

    Svensson, S. P.; Donetsky, D.; Wang, D.; Hier, H.; Crowne, F. J.; Belenky, G.

    2011-11-01

    We have examined the growth of strained layer superlattice (SLS) structures for the purpose of characterizing and improving the minority carrier lifetime. Structures with different SL periods but with same absorption wavelength were first studied. Despite a doubling of the number of interfaces per thickness unit, no significant change was seen in the carrier lifetime. This observation points away from the interfaces as the location of lifetime limiting defect centers. To gain further insights into the spatial location of the defect centers, a series of binary InAs and GaSb layers grown with different substrate temperatures, were studied. We found that higher growth temperatures were beneficial for both binaries, although the improvement for GaSb was less than that of InAs. The substrate temperature was also varied in SLS structures and characterized with high-resolution x-ray diffraction. By using the peak width from the SLS zero-order diffraction as a figure of merit, we found a shallow growth window of ?20 around an optimum temperature of 440 C. Outside this temperature window the material quality deteriorated very rapidly. Unfortunately, the substrate temperatures that would provide an improvement in the binary lifetimes fall mainly above the SLS growth window, thus limiting this parameter as a means of improving lifetimes in the SLS. A model that qualitatively relates bulk and SLS lifetimes through native defects is proposed and strategies for improving the lifetimes are discussed.

  16. Enhancement of electrochemical performance with Zn-Al-Bi layered hydrotalcites as anode material for Zn/Ni secondary battery

    International Nuclear Information System (INIS)

    Bi-doped Zn-Al layered double hydroxides (Zn-Al-Bi LDH) are prepared by the constant pH hydrothermal method and proposed as a novel anodic material in Zn/Ni secondary cells. The Fourier transform infrared spectra (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) images reveal that the as-prepared samples are well-crystallized and hexagon layer structure. The electrochemical performances of the Zn-Al-Bi LDH were analyzed by cyclic voltammetry, tafel plot, electrochemical impedance spectroscopy (EIS) and galvanostatic charge-discharge tests. Compared with Zn-Al LDH, Zn-Al-Bi LDH with different Zn/Al/Bi molar rations, especially the sample of Zn/Al/Bi = 3:0.8:0.2 (molar ration) have higher discharge capacity and more stable cycling performances. Cyclic voltammograms clearly illuminated that the Zn-Al-Bi LDHs could decrease polarization, maintain the electrochemical activity, and enhance the discharge capacity of Zn-Al LDH. This battery can undergo at least 800 charge-discharge cycles at constant current of 1C without dendrite and short circuits. The discharge capacity of Zn-Al-Bi LDH after the 800th cycle remains about 380 mAh g−1 and the hexagonal crystal structure have no much changed after cycles

  17. In situ high-temperature TEM observation of material escape from a surface of CoFeNi/Cu/ZrAlO composite into the amorphous carbon layer

    International Nuclear Information System (INIS)

    Highlights: We observed a moment of CoFeNi particle movement from surface into the carbon layer. Liquid-like behavior of the CoFeNi particles was detected. After heating, carbon layer became tightly packed with small particles and single atoms. Three main phases, CoFeNi, FePt, and W, were detected in the carbon layer. - Abstract: We observed the moment of material escape from a surface of CoFeNi/Cu/Zr(Al)O2 composite into the amorphous carbon layer when we studied the phase transformation of the structure using in situ transmission electron microscopy (TEM) technique at 800 C. To protect the top surface of the TEM specimen against focused-ion beam process damage, the specimen had been coated with an amorphous carbon layer, a thin Pt film and a W protective layer. During our high-temperature experiments at 800 C, we detected that the CoFeNi nanoparticles moved from the surface of the TEM specimen into the amorphous carbon layer. A porous amorphous carbon layer had a large impact on the visualization of this phenomenon. Liquid-like behavior of the CoFeNi phase, which possessed some crystalline order, was detected before the material escaped from the surface. After heating, the carbon layer became tightly packed with small particles and single atoms. The majority of the particles in the carbon layer were in the size range of 14 nm. The particles were assigned to the CoFeNi, FePt, and W phases. The CoFeNi particles escaped directly from the specimen surface, while the FePt and W particles were formed in the carbon layer during heating as a result of atomic reactions. The single atoms observed in the carbon layer were attributed to the heavy elements Pt and W

  18. Effect of initial stress on Love waves in a piezoelectric structure carrying a functionally graded material layer.

    Science.gov (United States)

    Qian, Zheng-Hua; Jin, Feng; Lu, Tianjian; Kishimoto, Kikuo; Hirose, Sohichi

    2010-01-01

    The effect of initial stress on the propagation behavior of Love waves in a piezoelectric half-space of polarized ceramics carrying a functionally graded material (FGM) layer is analytically investigated in this paper from the three-dimensional equations of linear piezoelectricity. The analytical solutions are obtained for the dispersion relations of Love wave propagating in this kind of structure with initial stress for both electrical open case and electrical short case, respectively. One numerical example is given to graphically illustrate the effect of initial stress on dispersive curve, phase velocity and electromechanical coupling factor of the Love wave propagation. The results reported here are meaningful for the design of surface acoustic wave (SAW) devices with high performance. PMID:19828172

  19. Flaw detection in a multi-material multi-layered composite: using fem and air-coupled ut

    International Nuclear Information System (INIS)

    Ceramic tiles are the main ingredient of a multi-layer multi-material composite being considered for the modernization of tank armors. The high stiffness, low attenuation, and precise dimensions of these uniform tiles make them remarkable resonators when driven to vibrate. This study is aimed at modeling the vibration modes of the tiles and the composite lay-up with finite element analysis and comparing the results with the resonance modes observed in air-coupled ultrasonic excitation of the tiles and armor samples. Defects in the tile, during manufacturing and/or after usage, are expected to change the resonance modes. The comparison of a pristine tile/lay-up and a defective tile/lay-up will thus be a quantitative damage metric. The understanding of the vibration behavior of the tile, both by itself and in the composite lay-up, can provide useful guidance to the nondestructive evaluation of armor panels containing ceramic tiles.

  20. Flaw Detection in a Multi-Material Multi-Layered Composite: Using FEM and Air-Coupled UT

    Science.gov (United States)

    Livings, R. A.; Dayal, V.; Barnard, D. J.; Hsu, D. K.

    2011-06-01

    Ceramic tiles are the main ingredient of a multi-layer multi-material composite being considered for the modernization of tank armors. The high stiffness, low attenuation, and precise dimensions of these uniform tiles make them remarkable resonators when driven to vibrate. This study is aimed at modeling the vibration modes of the tiles and the composite lay-up with finite element analysis and comparing the results with the resonance modes observed in air-coupled ultrasonic excitation of the tiles and armor samples. Defects in the tile, during manufacturing and/or after usage, are expected to change the resonance modes. The comparison of a pristine tile/lay-up and a defective tile/lay-up will thus be a quantitative damage metric. The understanding of the vibration behavior of the tile, both by itself and in the composite lay-up, can provide useful guidance to the nondestructive evaluation of armor panels containing ceramic tiles.

  1. Development of composite zirconium materials with increased level of properties and protective layers for new generation LWR active core components

    International Nuclear Information System (INIS)

    Methods are investigated to increase operation properties of zirconium items by modifying their structure-phase state: by liquid metal reinforcement by ordered structures, by methods of solid phase alloying by carbon nanostructures, by methods of granular metallurgy; and also by modifying the surface conditions: using dynamic impact of microbodies and applying of fine surface layers (coatings) by electroarc and magnetron sputtering. The investigations have resulted in obtaining several versions of composite materials based on Russian industrial zirconium alloys having an increased level of properties. The processes have been developed to modify surface and to make protective coatings on the surface of zirconium items. The developed modification methods can be used to increase operation properties and prolong service life of zirconium components of new generation LWR active cores. (author)

  2. Mechanically stacked 1 nm thick carbon nanosheets: Ultrathin layered materials with tunable optical, chemical and electrical properties

    CERN Document Server

    Nottbohm, Christoph T; Beyer, Andre; Stosch, Rainer; Golzhauser, Armin; 10.1002/smll.201001993

    2011-01-01

    Carbon nanosheets are mechanically stable free-standing two-dimensional materials with a thickness of ~1 nm and well defined physical and chemical properties. They are made by radiation induced cross-linking of aromatic self-assembled monolayers. Here we present a route to the scalable fabrication of multilayer nanosheets with tunable electrical, optical and chemical properties on insulating substrates. Stacks up to five nanosheets with sizes of ~1 cm^2 on oxidized silicon were studied. Their optical characteristics were investigated by visual inspection, optical microscopy, UV/Vis reflection spectroscopy and model calculations. Their chemical composition was studied by X-ray photoelectron spectroscopy. The multilayer samples were then annealed in ultra high vacuum at various temperatures up to 1100 K. A subsequent investigation by Raman, X-ray photoelectron and UV/Vis reflection spectroscopy as well as by electrical four-point probe measurements demonstrates that the layered nanosheets transform into nanocry...

  3. Ballistic impact properties of mixed multi-layered amorphous surface alloyed materials fabricated by high-energy electron-beam irradiation

    International Nuclear Information System (INIS)

    The objective of this study is to investigate ballistic impact properties of multi-layered amorphous surface alloyed materials fabricated by high-energy electron-beam irradiation. The mixture of Zr-based amorphous alloy powders and LiF+MgF2 flux powders was deposited on a Ti alloy substrate, and then electron beam was irradiated on this powder mixture to fabricate an one-layered surface alloyed material. On top of this layer, the powder mixture was deposited again and then irradiated with electron beam whose beam current was decreased to fabricate the multi-layered surface alloyed material. In the mixed multi-layered surface alloyed materials fabricated with LM1 alloy powders and LM2 or LM10 alloy powders, the surface region consisted of amorphous phases, together with a small amount of crystalline particles, whereas the center region was complicatedly composed of amorphous phases, crystallized phases, and dendritic ? phases. Since the surface region mostly composed of amorphous matrix was quite hard, the alloyed materials sufficiently blocked the travel of a projectile. When cracks formed at the surface region propagated into the center region, the formation of many cracks or debris was accelerated, which could beneficially work for absorbing the ballistic impact energy, thereby leading to the higher ballistic impact properties than the surface alloyed materials fabricated with LM1 or LM2 alloy powders

  4. Ballistic impact properties of mixed multi-layered amorphous surface alloyed materials fabricated by high-energy electron-beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Do, Jeonghyeon [High Temperature Materials Group, Korea Institute of Materials Science, Changwon 642-832 (Korea, Republic of); Jeon, Changwoo [Center for Advanced Aerospace Materials, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Song, Young Buem [Agency for Defense Development, Daejeon 300-600 (Korea, Republic of); Lee, Sunghak, E-mail: shlee@postech.ac.kr [Center for Advanced Aerospace Materials, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of)

    2014-03-01

    The objective of this study is to investigate ballistic impact properties of multi-layered amorphous surface alloyed materials fabricated by high-energy electron-beam irradiation. The mixture of Zr-based amorphous alloy powders and LiF+MgF{sub 2} flux powders was deposited on a Ti alloy substrate, and then electron beam was irradiated on this powder mixture to fabricate an one-layered surface alloyed material. On top of this layer, the powder mixture was deposited again and then irradiated with electron beam whose beam current was decreased to fabricate the multi-layered surface alloyed material. In the mixed multi-layered surface alloyed materials fabricated with LM1 alloy powders and LM2 or LM10 alloy powders, the surface region consisted of amorphous phases, together with a small amount of crystalline particles, whereas the center region was complicatedly composed of amorphous phases, crystallized phases, and dendritic ? phases. Since the surface region mostly composed of amorphous matrix was quite hard, the alloyed materials sufficiently blocked the travel of a projectile. When cracks formed at the surface region propagated into the center region, the formation of many cracks or debris was accelerated, which could beneficially work for absorbing the ballistic impact energy, thereby leading to the higher ballistic impact properties than the surface alloyed materials fabricated with LM1 or LM2 alloy powders.

  5. Long-term performance of different aluminum alloy designs as sacrificial anodes for rebars

    Directory of Open Access Journals (Sweden)

    de Rincn, O.

    2003-12-01

    Full Text Available This paper presents the performance of various cathodic-protection designs using Aluminum alloys to protect prestressed piles. The results obtained with different system designs (bracelete type-Al/Zn/In alloy, thermosprayed aluminum (3-year evaluation and conventional Al/Zn/In anocies in an epoxy-painted steel bracelet (12-year evaluation, indicated that all of these systems may be used as sacrificial anodes for pile protection. However, the thermosprayed aluminum type can not be used in prestressed concrete piles because the very negative potentials ( < -1100 mV vs. Cu/CuSO4 they supply to the reinforcement could lead to hydrogen embrittlement.

    Este trabajo presenta la realizacin de varios diseos de proteccin catdica utilizando aleaciones de aluminio para la proteccin de pilotes pretensados. Los resultados obtenidos con diferentes diseos (aleacin de Al/Zn/In, tipo brazalete y aluminio termorociado (3 aos de evaluacin y nodos convencionales de Al/Zn/In colocados en un brazalete de acero pintado con epoxy (12 aos de evaluacin, indicaron que todos estos sistemas pueden ser utilizados como nodos de sacrificio para la proteccin de los pilotes. Sin embargo, el sistema con aluminio termorociado no puede ser utilizado en pilotes de acero pretensado debido al potencial muy negativo alcanzado por la armadura (<-1100 mV vs Cu/CuSO4, lo cual podra inducir a daos por hidrgeno.

  6. Electrochemical treatment of Orange II dye solution-Use of aluminum sacrificial electrodes and floc characterization

    International Nuclear Information System (INIS)

    Electrocoagulation (EC) of Orange II dye in a flow through cell with aluminum as sacrificial electrodes was carried out under varying conditions of dye concentration, current density, flow rate, conductivity, and the initial pH of the solution in order to optimize the operating parameters for maximum benefits. Maximum removal efficiency of 94.5% was obtained at the following conditions: dye concentration = 10 ppm, current density = 160 A/m2, initial pH 6.5, conductance = 7.1 mS/cm, flow rate = 350 mL/min, and concentration of added NaCl = 4.0 g/L of dye solution. The EC-floc was characterized using Fourier transform infrared spectroscopy, scanning electron microscopy/energy dispersive X-ray spectroscopy, and powder X-ray diffraction techniques. The removal mechanism has been proposed that is in compliance with the Pourbaix diagram, solubility curve of aluminum oxides/hydroxides, and physico-chemical properties of the EC-floc.

  7. Colloidal processing and CO2 capture performance of sacrificially templated zeolite monoliths

    International Nuclear Information System (INIS)

    Highlights: ? We demonstrate structuring of hierarchically porous zeolite monoliths. ? Structured zeolite monoliths show high CO2 adsorption capacity. ? Addition of 5 wt% of kaolin to zeolite monoliths ensures a mechanical stability. ? Cyclic adsorption and regeneration show that structured monoliths are robust. -- Abstract: Sacrificial templating of suspension cast and subsequently thermally treated zeolite monoliths with glassy carbon spheres and fibers yielded zeolite 13X and silicalite-1 monoliths with macroporosities up to 50 vol%. Homogeneous distribution of the macroporosity in hierarchically porous monoliths was obtained by tailoring the surface chemistry of the carbon particles by polyelectrolyte-assisted adsorption of zeolite particles. The effect of amount of kaolin binder and temperature for the thermal treatment on the monoliths strength, surface area and CO2 uptake was studied by diametral compression tests, electron microscopy, X-ray diffraction and gas adsorption. Cyclic adsorption and regeneration measurements showed that zeolite 13X monoliths display a high CO2 uptake while the silicalite-1 monoliths could be regenerated with a relatively low energy penalty.

  8. Deoxyguanosine phosphate mediated sacrificial bonds promote synergistic mechanical properties in nacre-mimetic nanocomposites.

    Science.gov (United States)

    Martikainen, Lahja; Walther, Andreas; Seitsonen, Jani; Berglund, Lars; Ikkala, Olli

    2013-08-12

    We show that functionalizing polymer-coated colloidal nanoplatelets with guanosine groups allows synergistic increase of mechanical properties in nacre-mimetic lamellar self-assemblies. Anionic montmorillonite (MTM) was first coated using cationic poly(diallyldimethylammonium chloride) (PDADMAC) to prepare core-shell colloidal platelets, and subsequently the remaining chloride counterions allowed exchange to functional anionic 2'-deoxyguanosine 5'-monophosphate (dGMP) counterions, containing hydrogen bonding donors and acceptors. The compositions were studied using elemental analysis, scanning and transmission electron microscopy, wide-angle X-ray scattering, and tensile testing. The lamellar spacing between the clays increases from 1.85 to 2.14 nm upon addition of the dGMP. Adding dGMP increases the elastic modulus, tensile strength, and strain 33.0%, 40.9%, and 5.6%, respectively, to 13.5 GPa, 67 MPa, and 1.24%, at 50% relative humidity. This leads to an improved toughness seen as a ca. 50% increase of the work-to-failure. This is noteworthy, as previously it has been observed that connecting the core-shell nanoclay platelets covalently or ionically leads to increase of the stiffness but to reduced strain. We suggest that the dynamic supramolecular bonds allow slippage and sacrificial bonds between the self-assembling nanoplatelets, thus promoting toughness, still providing dynamic interactions between the platelets. PMID:23822180

  9. Synthesis of porous silica hollow spheres using sacrificial template for drug delivery applications

    Directory of Open Access Journals (Sweden)

    Rasoul Safdari

    2014-06-01

    Full Text Available In this work, we report on the synthesis of SiO2 hollow spheres using carbon nanospheres as the sacrificial template by hydrothermal method. The synthesized substrates are in a spherical morphology and uniform size distribution. The effects of hydrothermal process, concentration and the reaction temperature were optimized during synthesis of carbon nanospheres. Infrared spectroscopy (IR, and scanning electronic microscopy (SEM methods were used for identification of the synthesized products. The synthesized SiO2 nanospheres were used as drug carrier to investigate in vitro release behavior of monoterpenic phenol isomers, carvacrol and thymol, in simulated body fluid (SBF. Ultraviolet-visible spectroscopy (UV-vis method was carried out to determine the amount of the drugs entrapped in the carrier. The results indicated that SiO2 nanospheres have high ability to adsorb the drugs and there is no need for adjusting the pH during the adsorption process. The drug release profile shows a three stages pattern and indicates a delayed release action.

  10. The properties of thickness-twist (TT) wave modes in a rotated Y-cut quartz plate with a functionally graded material top layer.

    Science.gov (United States)

    Wang, Bin; Qian, Zhenghua; Li, Nian; Sarraf, Hamid

    2016-01-01

    We propose the use of thickness-twist (TT) wave modes of an AT-cut quartz crystal plate resonator for measurement of material parameters, such as stiffness, density and material gradient, of a functionally graded material (FGM) layer on its surface, whose material property varies exponentially in thickness direction. A theoretical analysis of dispersion relations for TT waves is presented using Mindlin's plate theory, with displacement mode shapes plotted, and the existence of face-shear (FS) wave modes discussed. Through numerical examples, the effects of material parameters (stiffness, density and material gradient) on dispersion curves, cutoff frequencies and mode shapes are thoroughly examined, which can act as a theoretical reference for measurements of unknown properties of FGM layer. PMID:26254981

  11. Stacking sequence determines Raman intensities of observed interlayer shear modes in 2D layered materials--A general bond polarizability model.

    Science.gov (United States)

    Luo, Xin; Lu, Xin; Cong, Chunxiao; Yu, Ting; Xiong, Qihua; Quek, Su Ying

    2015-01-01

    2D layered materials have recently attracted tremendous interest due to their fascinating properties and potential applications. The interlayer interactions are much weaker than the intralayer bonds, allowing the as-synthesized materials to exhibit different stacking sequences, leading to different physical properties. Here, we show that regardless of the space group of the 2D materials, the Raman frequencies of the interlayer shear modes observed under the typical z(xx)z configuration blue shift for AB stacked materials, and red shift for ABC stacked materials, as the number of layers increases. Our predictions are made using an intuitive bond polarizability model which shows that stacking sequence plays a key role in determining which interlayer shear modes lead to the largest change in polarizability (Raman intensity); the modes with the largest Raman intensity determining the frequency trends. We present direct evidence for these conclusions by studying the Raman modes in few layer graphene, MoS2, MoSe2, WSe2 and Bi2Se3, using both first principles calculations and Raman spectroscopy. This study sheds light on the influence of stacking sequence on the Raman intensities of intrinsic interlayer modes in 2D layered materials in general, and leads to a practical way of identifying the stacking sequence in these materials. PMID:26469313

  12. Properties of the material spontaneously formed in interfacial layer of system at extraction of rare-earth elements

    Science.gov (United States)

    Kizim, N. F.; Golubina, E. N.; Chekmarev, A. M.

    2013-03-01

    The wetting ability of the material formed spontaneously in the interface layer of an aqueous solution of a rare-earth element (REE) salt/solution of di-(2-ethylhexyl)phosphoric acid (D2EHPA) extraction system adhered onto a glass plate is investigated. It is found that its properties depend on the natures of the REE and the solvent, and the initial concentrations of the REE and the extracting reactant. It is shown that the material formed at the interface and adhered onto a glass plate has controlled wetting ability. The difference between the properties of interface REE formations for yttrium and cerium subgroups is established. The electric conductivity of interphase formations in the same systems is measured and shown to display an extreme dependence on time in systems with heptane but a monotonically increasing one in systems with toluene. It is shown that the electric conductivity of interphase formations diminishes sharply with an increase in the ratio of the initial concentrations of REE salt and D2EHPA. It is concluded that an increase in the relative gain of the average molar mass of interphase formations indicates coagulation and the formation of polymers.

  13. High-performance hierarchical LiNi1/3Mn1/3Co1/3O2 microspheres synthesized via a facile template-sacrificial route

    International Nuclear Information System (INIS)

    Highlights: Microsphere hierarchical LiNi1/3Mn1/3Co1/3O2 was fabricated. A facile in situ route with MnO2 as the sacrificial template was developed. Conventional co-precipitate synthesis method was compared. The hierarchical microsphere sample exhibits superior electrochemical performance. -- Abstract: LiNi1/3Mn1/3Co1/3O2 microspheres have been successfully synthesized via a facile in situ route with MnO2 as the sacrificial template. The as-obtained sample shows a unique nano/micro-hierarchical structure. As a cathode material for lithium-ion battery, the sample exhibits excellent electrochemical performance with higher capacity, superior cycling stability and rate capability as compared with that prepared by conventional co-precipitate reaction method. The discharge specific capacities for the first cycle are 196, 187, 182 and 176 mA h g?1 at 0.1, 0.2, 0.5 and 1 C, respectively. The superior performance can be ascribed to the unique microstructure with numerous nanosized primary particles that can provide rapid pathway for Li+ and e? diffusion, and facilitate the penetration of the electrolyte

  14. Materials and proportion's design of self-compacting mortar used for low diffusion layer in sub-surface radioactive waste disposal facility in Japan

    International Nuclear Information System (INIS)

    This paper describes the design procedure for the material selection and mix proportion of the self-compacting mortar used for low diffusion layer cementitious material in the sub-surface radioactive waste disposal facility in Japan. The low diffusion layer is required for reducing transportation by controlling diffusion of a radionuclide. Therefore the low diffusion, cracks control, and low leaching are the important matters in the mix design. The process to select mortar mix design of the low diffusion layer is explained in detail. Of 33 kinds mix proportions used in laboratory comparative testing, the combinations of low heat portland cement, fly ash, lime powder and expansive addition was provisionally set to the mix proportion of the self-compacting mortar used for low diffusion layer. (author)

  15. High-efficiency exfoliation of layered materials into 2D nanosheets in switchable CO2/Surfactant/H2O system

    Science.gov (United States)

    Wang, Nan; Xu, Qun; Xu, Shanshan; Qi, Yuhang; Chen, Meng; Li, Hongxiang; Han, Buxing

    2015-11-01

    Layered materials present attractive and important properties due to their two-dimensional (2D) structure, allowing potential applications including electronics, optoelectronics, and catalysis. However, fully exploiting the outstanding properties will require a method for their efficient exfoliation. Here we present that a series of layered materials can be successfully exfoliated into single- and few-layer nanosheets using the driving forces coming from the phase inversion, i.e., from micelles to reverse micelles in the emulsion microenvironment built by supercritical carbon dioxide (SC CO2). The effect of variable experimental parameters including CO2 pressure, ethanol/water ratio, and initial concentration of bulk materials on the exfoliation yield have been investigated. Moreover, we demonstrate that the exfoliated 2D nanosheets have their worthwhile applications, for example, graphene can be used to prepare conductive paper, MoS2 can be used as fluorescent label to perform cellular labelling, and BN can effectively reinforce polymers leading to the promising mechanical properties.

  16. Diseo de aleaciones para nodos de sacrificio sustentables / Designing alloys for sustainable sacrificial anodes

    Scientific Electronic Library Online (English)

    Guillermo, Salas-Banuet; Laura, Verduzco-Flores.

    2013-06-01

    Full Text Available Se presenta: un proceso de diseo de aleaciones para fabricar nodos de sacrificio, usados en ambientes marinos; la propuesta de sustituir al In con Ag, en aleaciones Al-Zn-In, buscando sustentar el medio ambiente; y la proposicin de incluir los parmetros de los procesos de fabricacin de nodos y [...] los estructurales en la normatividad sobre nodos de sacrificio. Se manufacturaron en el laboratorio, se ensayaron y compararon ocho aleaciones Al-Zn 2% (contenido menor al que seala la norma para aleaciones con In (de 3.5 a 5%) y con Sn (de 4 a 5%), buscando mayor sustentabilidad); cuatro se alearon con In (de 0.59 a 0.766%) y cuatro con Ag (de 0.23 a 0.428%). Se usaron dos rapideces de enfriamiento durante la solidificacin, buscando modificar la estructura y cambiar propiedades y comportamientos ante la corrosin -el potencial de corrosin, la rapidez de corrosin, la activacin del nodo, el tipo de corrosin y la eficiencia de corriente-. se evaluaron las estructuras y se midieron sus potenciales; se encontr que la variacin de la rapidez de enfriamiento modific la estructura de las aleaciones, sus propiedades y comportamientos ante la corrosin y que el comportamiento general de algunas de las aleaciones con Ag es superior a las que contienen in. Las mayores eficiencias se dieron en las aleaciones con menor contenido de In (69%) y de Ag (71%). Abstract in english In this paper we present: a) a design process for manufacturing alloys to be used as sacrificial anodes in marine environments; b) the proposal to replace in with Ag, in search of alloys that could contribute to environmental sustain; and c) the proposal to include the parameters related to anode st [...] ructure and their manufacturing process in the regulation of sacrificial anodes. Eight Al-Zn 2% alloys were manufactured, tested, and compared in our laboratory. These had a lower content than the one indicated by the alloy standards - 3.5-5% and 4-5% content for in and Sn respectively- looking for a more sustainable environment. Four of them were alloyed with In (from 0.59 to 0.766%), and four with Ag (from 0.23 to 0.428%). in order to modify the structure, two cooling rates were used during solidification, seeking to modify their properties, and hence their behavior against corrosion, i.e. corrosion potential, corrosion rate, anode activation, type of corrosion and current efficiency. It was found that the variation of the cooling rate changes the structure of the alloys, their properties and corrosion behaviors. The overall behavior of some of the Ag alloys is superior to those containing In. The higher efficiencies were obtained for alloys with the lower amount of In (69%) and Ag (71%).

  17. A potential role for endogenous proteins as sacrificial sunscreens and antioxidants in human tissues.

    Science.gov (United States)

    Hibbert, Sarah A; Watson, Rachel E B; Gibbs, Neil K; Costello, Patrick; Baldock, Clair; Weiss, Anthony S; Griffiths, Christopher E M; Sherratt, Michael J

    2015-08-01

    Excessive ultraviolet radiation (UVR) exposure of the skin is associated with adverse clinical outcomes. Although both exogenous sunscreens and endogenous tissue components (including melanins and tryptophan-derived compounds) reduce UVR penetration, the role of endogenous proteins in absorbing environmental UV wavelengths is poorly defined. Having previously demonstrated that proteins which are rich in UVR-absorbing amino acid residues are readily degraded by broadband UVB-radiation (containing UVA, UVB and UVC wavelengths) here we hypothesised that UV chromophore (Cys, Trp and Tyr) content can predict the susceptibility of structural proteins in skin and the eye to damage by physiologically relevant doses (up to 15.4J/cm(2)) of solar UVR (95% UVA, 5% UVB). We show that: i) purified suspensions of UV-chromophore-rich fibronectin dimers, fibrillin microfibrils and ?- and ?-lens crystallins undergo solar simulated radiation (SSR)-induced aggregation and/or decomposition and ii) exposure to identical doses of SSR has minimal effect on the size or ultrastructure of UV chromophore-poor tropoelastin, collagen I, collagen VI microfibrils and ?-crystallin. If UV chromophore content is a factor in determining protein stability in vivo, we would expect that the tissue distribution of Cys, Trp and Tyr-rich proteins would correlate with regional UVR exposure. From bioinformatic analysis of 244 key structural proteins we identified several biochemically distinct, yet UV chromophore-rich, protein families. The majority of these putative UV-absorbing proteins (including the late cornified envelope proteins, keratin associated proteins, elastic fibre-associated components and ?- and ?-crystallins) are localised and/or particularly abundant in tissues that are exposed to the highest doses of environmental UVR, specifically the stratum corneum, hair, papillary dermis and lens. We therefore propose that UV chromophore-rich proteins are localised in regions of high UVR exposure as a consequence of an evolutionary pressure to express sacrificial protein sunscreens which reduce UVR penetration and hence mitigate tissue damage. PMID:25911998

  18. Effect of Capping Front Layer Materials on the Penetration Resistance of Q&T Steel Welded Joints Against 7.62-mm Armor-Piercing Projectile

    Science.gov (United States)

    Balakrishnan, M.; Balasubramanian, V.; Madhusudhan Reddy, G.; Parameswaran, P.

    2013-09-01

    In the present investigation, an attempt has been made to study the effect of capping front layers on the ballistic performance of shielded metal arc-welded armor steel joints which were fabricated with a chromium carbide-rich hardfaced middle layer on the buttered/beveled edge. Two different capping front layer materials were chosen for achieving better ballistic performance, namely, low hydrogen ferritic (LHF) and austenitic stainless steel (SS) fillers. On the other hand, the bottom layers are welded with SS filler for both joints. The consequent sandwiched joint served the dual purpose of weld integrity and penetration resistance of the bullet. It is observed that the penetration resistance is due to the high hardness of the hardfacing layer on the one hand and the energy-absorbing capacity of the soft backing SS weld deposits on the other hand. The complementary effect of layers successfully provided resistance to the projectile penetration. On a comparative analysis, the joint fabricated using the LHF filler capping front layer offered superior ballistic performance with respect to depth of penetration. This is mainly due to the presence of acicular ferrite along the bainitic structure in the LHF capping front layer, which caused a shallow hardness gradient along the weld center line.

  19. Sodium Montmorillonite/Amine-Containing Drugs Complexes: New Insights on Intercalated Drugs Arrangement into Layered Carrier Material

    Science.gov (United States)

    Vieira, Brbara A.; Dias, Luiza R. S.; de Sousa, Valria P.; Castro, Helena C.; Rodrigues, Carlos R.; Cabral, Lucio M.

    2015-01-01

    Layered drug delivery carriers are current targets of nanotechnology studies since they are able to accommodate pharmacologically active substances and are effective at modulating drug release. Sodium montmorillonite (Na-MMT) is a clay that has suitable properties for developing new pharmaceutical materials due to its high degree of surface area and high capacity for cation exchange. Therefore Na-MMT is a versatile material for the preparation of new drug delivery systems, especially for slow release of protonable drugs. Herein, we describe the intercalation of several amine-containing drugs with Na-MMT so we can derive a better understanding of how these drugs molecules interact with and distribute throughout the Na-MMT interlayer space. Therefore, for this purpose nine sodium montmorillonite/amine-containing drugs complexes (Na-MMT/drug) were prepared and characterized. In addition, the physicochemical properties of the drugs molecules in combination with different experimental conditions were assessed to determine how these factors influenced experimental outcomes (e.g. increase of the interlayer spacing versus drugs arrangement and orientation). We also performed a molecular modeling study of these amine-containing drugs associated with different Na-MMT/drug complex models to analyze the orientation and arrangement of the drugs molecules in the complexes studied. Six amine-containing drugs (rivastigmine, doxazosin, 5-fluorouracil, chlorhexidine, dapsone, nystatin) were found to successfully intercalate Na-MMT. These findings provide important insights on the interlayer aspect of the molecular systems formed and may contribute to produce more efficient drug delivery nanosystems. PMID:25803292

  20. Highly Dispersed Ultrafine Pt Nanoparticles on Reduced Graphene Oxide Nanosheets: In Situ Sacrificial Template Synthesis and Superior Electrocatalytic Performance for Methanol Oxidation.

    Science.gov (United States)

    Wu, Shouliang; Liu, Jun; Tian, Zhenfei; Cai, Yunyu; Ye, Yixing; Yuan, Qinglin; Liang, Changhao

    2015-10-21

    We report a simple and environmentally friendly route to prepare platinum/reduced graphene oxide (Pt/rGO) nanocomposites (NCs) with highly reactive MnOx colloids as reducing agents and sacrificial templates. The colloids are obtained by laser ablation of a metallic Mn target in graphene oxide (GO)-containing solution. Structural and morphological investigations of the as-prepared NCs revealed that ultrafine Pt nanoparticles (NPs) with an average size of 1.8 (0.6) nm are uniformly dispersed on the surfaces of rGO nanosheets. Compared with commercial Pt/C catalysts, Pt/rGO NCs with highly electrochemically active surface areas show remarkably improved catalytic activity and durability toward methanol oxidation. All of these superior characteristics can be attributed to the small particle size and uniform distribution of the Pt NPs, as well as the excellent electrical conductivity and stability of the rGO catalyst support. These findings suggest that Pt/rGO electrocatalysts are promising candidate materials for practical use in fuel cells. PMID:26435201

  1. Photomultiplication photodetectors with P3HT:fullerene-free material as the active layers exhibiting a broad response

    Science.gov (United States)

    Wang, Wenbin; Zhang, Fujun; Bai, Huitao; Li, Lingliang; Gao, Mile; Zhang, Miao; Zhan, Xiaowei

    2016-03-01

    A series of polymer photodetectors (PPDs) are fabricated based on P3HT as an electron donor and fullerene-free material DC-IDT2T as an electron acceptor. The only difference among these PPDs is the P3HT:DC-IDT2T doping weight ratios from 2 : 1 to 150 : 1. The PPDs with P3HT:DC-IDT2T (100 : 1, w/w) as the active layers exhibit champion external quantum efficiency (EQE) of 28 000% and 4000% corresponding to 390 nm and 750 nm light illumination at -20 V bias, respectively. The photomultiplication (PM) phenomenon should be attributed to the enhanced hole tunneling injection due to the interfacial band bending, which is induced by the trapped electrons in DC-IDT2T near the Al cathode. The high EQE value in the long wavelength range is due to the effect of DC-IDT2T photon harvesting and exciton dissociation on the interfacial trap-assisted hole tunneling injection. Meanwhile, the PPDs with DC-IDT2T as the electron acceptor exhibit superior stability compared with the PPDs with PC71BM as the electron acceptor.A series of polymer photodetectors (PPDs) are fabricated based on P3HT as an electron donor and fullerene-free material DC-IDT2T as an electron acceptor. The only difference among these PPDs is the P3HT:DC-IDT2T doping weight ratios from 2 : 1 to 150 : 1. The PPDs with P3HT:DC-IDT2T (100 : 1, w/w) as the active layers exhibit champion external quantum efficiency (EQE) of 28 000% and 4000% corresponding to 390 nm and 750 nm light illumination at -20 V bias, respectively. The photomultiplication (PM) phenomenon should be attributed to the enhanced hole tunneling injection due to the interfacial band bending, which is induced by the trapped electrons in DC-IDT2T near the Al cathode. The high EQE value in the long wavelength range is due to the effect of DC-IDT2T photon harvesting and exciton dissociation on the interfacial trap-assisted hole tunneling injection. Meanwhile, the PPDs with DC-IDT2T as the electron acceptor exhibit superior stability compared with the PPDs with PC71BM as the electron acceptor. Electronic supplementary information (ESI) available: J-V curves of PPDs; J-V curves of the electron-only and hole-only devices; EQE spectra of the PPDs with different thicknesses of P3HT : DC-IDT2T (2 : 1, w/w) as the active layers under -10 V bias; light intensity spectrum of the monochromatic light through a monochromator; EQE spectra of the PPDs measured under -10 V bias after different storage times. See DOI: 10.1039/c6nr00079g

  2. Theory of the axi-symmetric extrusion process of multi-layer materials with a strong plastic nonhomogeneity

    Directory of Open Access Journals (Sweden)

    J. Piwnik

    2008-03-01

    Full Text Available A novel simplified r hcorctical solution is found lor thc strcss starcs accompanying thc proccss of cxt ri~siono f ma![ i-laycr matcrialsunder rhc conditions af axial symmetry. Thc solution i~ bawd nn ~ h mc n dcl of pcrfcct plastic material satisfying thc Trcsca yicld condition.thc Haar-Karman conditions bcing sntisficd in each layer. Thc laycrs arc chnnctcrizcd by difrercnt yicld limits and stmng plasticnonhomogeneity. In thc ncighhoi~rhoorol f thc interfaces conrinuous variation of rhc yicld limit i s a~sunicdZ. hc form of thc plastic zonc nndpsitions or the contact surfi~ccss eparating rhc laycrs nrc assumcd. Shcaring strcsscs and mcan prcssurc in a longitudinal scclion o f t hccxrruded rod arc cxprcsscd in tcrms of filnctions of the axial coordinatc z. Unknown fttnctions of thc singlc coordinatc z arc dctcrmincdFrom thc yicld conditions writtcn for thc contour of thc die. Accitratc analytical relations arc dcrivcd For tllc normal strcss distribution atthc surface of contact bctwccn thc dic and thc matcrial cxlrudcd, Using thc known normal and shcar stress dislrihutions (due to Iriclion,accuratc valuc of thc lower cstimate of thc cxtrusion forcc is dctcrrnincd. Thc sotution may hc applicd lo ~ h cca scs of arbitrary numhcr oflaycrs and arbitrary h rm oithc dic. I t may bc used to a rational analysis o f ~ h pcro ccss of cxirnsiol~o f multi-lnycr cylindrical rods.

  3. Design and performance of a cryogenic scanning tunneling microscope in high magnetic field for 2D layered materials study

    Science.gov (United States)

    Chuang, Tien-Ming; Chung, Pei-Fang; Guan, Syu-You; Yu, Shan-An; Liu, Che-An; Hsu, Chia-Sheng; Su, Chih-Chuan; Sankar, Raman; Chou, Fang-Cheng

    2015-03-01

    We will describe the design and performance of a cryogenic scanning tunneling microscope (STM) system in a high magnetic field. A Pan-type STM is mounted on a homemade low vibration 4He pot refrigerator, which can be operated in continuous flow mode at T ~ 1.6K and in a magnetic field of up to 9 Tesla. A cleavage device at T =4.2K stage is used to cleave the 2D layered materials before inserting into STM as well as functioning as the radiation shield. The liquid helium boil rate of 4.6 liters per day is achieved due to our careful design, which allows the measurement at base temperature up to 10 days. We will demonstrate its capability of measuring atomically registered energy resolved spectroscopic maps in both real space and momentum space by our recent results on Rashba BiTeI. This work is supported by Ministry of Science and Technology, Taiwan and Kenda Foundation, Taiwan.

  4. Atomic-Resolution Visualization of Distinctive Chemical Mixing Behavior of Ni, Co and Mn with Li in Layered Lithium Transition-Metal Oxide Cathode Materials

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Pengfei; Zheng, Jianming; Lv, Dongping; Wei, Yi; Zheng, Jiaxin; Wang, Zhiguo; Kuppan, Saravanan; Yu, Jianguo; Luo, Langli; Edwards, Danny J.; Olszta, Matthew J.; Amine, Khalil; Liu, Jun; Xiao, Jie; Pan, Feng; Chen, Guoying; Zhang, Jiguang; Wang, Chong M.

    2015-07-06

    Capacity and voltage fading of layer structured cathode based on lithium transition metal oxide is closely related to the lattice position and migration behavior of the transition metal ions. However, it is scarcely clear about the behavior of each of these transition metal ions. We report direct atomic resolution visualization of interatomic layer mixing of transition metal (Ni, Co, Mn) and lithium ions in layer structured oxide cathodes for lithium ion batteries. Using chemical imaging with aberration corrected scanning transmission electron microscope (STEM) and DFT calculations, we discovered that in the layered cathodes, Mn and Co tend to reside almost exclusively at the lattice site of transition metal (TM) layer in the structure or little interlayer mixing with Li. In contrast, Ni shows high degree of interlayer mixing with Li. The fraction of Ni ions reside in the Li layer followed a near linear dependence on total Ni concentration before reaching saturation. The observed distinctively different behavior of Ni with respect to Co and Mn provides new insights on both capacity and voltage fade in this class of cathode materials based on lithium and TM oxides, therefore providing scientific basis for selective tailoring of oxide cathode materials for enhanced performance.

  5. Analysis of the Deformability of Two-Layer Materials AZ31/Eutectic / Analiza Mo?liwo?ci Odkszta?cania Plastycznego Materia?u Dwuwarstwowego AZ31/Eutektyka

    Directory of Open Access Journals (Sweden)

    Mola R.

    2015-12-01

    Full Text Available The paper present the results of physical simulation of the deformation of the two-layered AZ31/eutectic material using the Gleeble 3800 metallurgical processes simulator. The eutectic layer was produced on the AZ31 substrate using thermochemical treatment. The specimens of AZ31 alloy were heat treated in contact with aluminium powder at 445C in a vacuum furnace. Depending on the heating time, Al-enriched surface layers with a thickness of 400, 700 and 1100 ?m were fabricated on a substrate which was characterized by an eutectic structure composed of the Mg17Al12 phase and a solid solution of aluminium in magnesium. In the study, physical simulation of the fabricated two-layered specimens with a varying thickness of the eutectic layer were deformed using the plane strain compression test at various values of strain rates. The testing results have revealed that it is possible to deform the two-layered AZ31/eutectic material at low strain rates and small deformation values.

  6. Methodological research with ion beams and thin layer activation techniques for materials characterization at micrometric and submicrometric depth

    International Nuclear Information System (INIS)

    Analysis and materials characterization is a permanent concern of our department. Advantages and complementarity as compared to conventional technologies are due to the high sensitivity, quick results and nondestructive character of most ion beam technologies. Regarding technical parameters of IFIN-HH accelerators (Tandem and Cyclotron) there were three main objectives: 1. Updating cyclotron dedicated extension for Thin Layer Activation (TLA) techniques used in wear/corrosion studies and other tribological phenomenon. This technique permits radioactive surface labelling of metallic structures at depths up to 300 micrometers, and spectroscopic techniques with dedicated electromechanical installations allows wear/corrosion determinations to be made for various mechanical parts. During 1992-1998 this issue was part of two international research programs coordinated by IAEA Vienna. In cooperation with JRC-IAM from Ispra Italy, CNRS-CERI from Orleans France, MASTER SA and ICTCM from Bucharest, Romania, we proposed a TTQM project; 2. Method and irradiating device for developing implant recoil technique used in tribological studies (wear/corrosion, material transfer, diffusion etc.) at submicrometric depths. This technique which do not require a direct interaction of ion beam with the target, permits radioactive labelling of materials such as metals, plastics and ceramic at depths of 100-300 nanometers. The calibration operations for radioactivity/depth correlation, request RBS, ERDA, PIXE and XRF techniques; 3. The positron source project were continued with the experiments on the on and off-line version using positron sources produced in the cyclotron, to gain experience with detection chains and to study and design the different versions for the on-line production of positrons with cyclotron. In the first stage the nuclear reaction 48Ti(p,n)48V was used. 48V radioisotope decays with a 56% branching ratio by emitting positrons with the maximum energy of 0.7 MeV with a half-time of 16 days. We use these sources for testing the performances of our installations and detectors in Doppler broadening measurements on copper, lead, aluminum and indium. In the frame of a Cooperation Agreement with the Institute for Applied Physics from Chisinau, some positron lifetime preliminaries measurements were made, for which we needed also a fast coincidence device equipped with two fast detectors. (authors)

  7. Development of a helium-cooled divertor: Material choice and technological studies

    International Nuclear Information System (INIS)

    Within the framework of the EU power plant conceptual study (PPCS), a He-cooled divertor concept has been investigated at Forschungszentrum Karlsruhe in cooperation with the Efremov Institute. The design goal is to remove a high heat load of at least 10 MW/m2. The design is based on a modular construction of cooling finger unit that helps reduce thermal stresses. The divertor finger unit, which is cooled by high pressure helium, consists of a tungsten tile as thermal shield and sacrificial layer, and a thimble made of tungsten alloy. The success of this design depends strongly on the effectiveness of the cooling technology and on the availability of appropriate structural materials such as tungsten alloy and oxide-dispersion-strengthened (ODS) steel as well as the related fabrication and joining technology. Results of this investigation are discussed in the paper

  8. Influence of positive active material type and grid alloy on corrosion layer structure and composition in the valve regulated lead/acid battery

    Science.gov (United States)

    Ball, R. J.; Kurian, R.; Evans, R.; Stevens, R.

    Performance of a valve regulated lead/acid battery is affected by the properties of the positive grid corrosion layer. An investigation has been carried out using a range of experimental techniques to study the influence of corrosion layer composition and structure on cyclic performance. A number of designs of battery were manufactured with different grids and positive active materials (PAMs). Two grid types were used consisting of either pure lead or a lead/tin alloy. Variations in PAM composition and structure were obtained by forming electrodes from grey oxide pastes containing additions of, red lead, tetrabasic lead sulphate, or sulphuric acid (sulphated). Results indicated that both grid alloy composition and PAM type affect the corrosion layer properties. Ultra-microtoming was used to prepare sections of the grid/corrosion layer interface. Results showed that corrosion propagated along tin rich grain boundaries.

  9. Layer Transfer of Cu(In,Ga)Se2 Thin Film and Solar Cell Fabrication

    Science.gov (United States)

    Minemoto, Takashi; Anegawa, Takaya; Osada, Shintaro; Takakura, Hideyuki

    2010-01-01

    Cu(In,Ga)Se2 (CIGS) thin films were transferred to alternative substrates by a lift-off process, and solar cells were fabricated using the transferred films. CIGS films were grown on Mo/soda-lime glass (SLG) substrates by a three-stage evaporation process. The CIGS films were transferred to two alternative substrates: a rigid SLG and a flexible polyimide film. In the lift-off process, an intentional sacrificial layer between CIGS and Mo back contact layers was not prepared. CIGS solar cells with In2O3:Sn/ZnO/CdS/CIGS/Mo/conductive-epoxy/alternative-substrates structure were fabricated. Both solar cells showed almost half of the conversion efficiencies of a CIGS solar cell fabricated by a standard process. This is because of poor short circuit current and fill factor due to voltage-dependent current collection and high series resistance. Modifications of the composition profile of the CIGS layer and back contact property will improve the device performance. These results demonstrated the possibility of using the lift-off process for CIGS solar cells to widen the variety of substrate material choice.

  10. A potential role for endogenous proteins as sacrificial sunscreens and antioxidants in human tissues

    Directory of Open Access Journals (Sweden)

    Sarah A. Hibbert

    2015-08-01

    Full Text Available Excessive ultraviolet radiation (UVR exposure of the skin is associated with adverse clinical outcomes. Although both exogenous sunscreens and endogenous tissue components (including melanins and tryptophan-derived compounds reduce UVR penetration, the role of endogenous proteins in absorbing environmental UV wavelengths is poorly defined. Having previously demonstrated that proteins which are rich in UVR-absorbing amino acid residues are readily degraded by broadband UVB-radiation (containing UVA, UVB and UVC wavelengths here we hypothesised that UV chromophore (Cys, Trp and Tyr content can predict the susceptibility of structural proteins in skin and the eye to damage by physiologically relevant doses (up to 15.4 J/cm2 of solar UVR (95% UVA, 5% UVB. We show that: i purified suspensions of UV-chromophore-rich fibronectin dimers, fibrillin microfibrils and β- and γ-lens crystallins undergo solar simulated radiation (SSR-induced aggregation and/or decomposition and ii exposure to identical doses of SSR has minimal effect on the size or ultrastructure of UV chromophore-poor tropoelastin, collagen I, collagen VI microfibrils and α-crystallin. If UV chromophore content is a factor in determining protein stability in vivo, we would expect that the tissue distribution of Cys, Trp and Tyr-rich proteins would correlate with regional UVR exposure. From bioinformatic analysis of 244 key structural proteins we identified several biochemically distinct, yet UV chromophore-rich, protein families. The majority of these putative UV-absorbing proteins (including the late cornified envelope proteins, keratin associated proteins, elastic fibre-associated components and β- and γ-crystallins are localised and/or particularly abundant in tissues that are exposed to the highest doses of environmental UVR, specifically the stratum corneum, hair, papillary dermis and lens. We therefore propose that UV chromophore-rich proteins are localised in regions of high UVR exposure as a consequence of an evolutionary pressure to express sacrificial protein sunscreens which reduce UVR penetration and hence mitigate tissue damage.

  11. Magnesium-containing layered double hydroxides as orthopaedic implant coating materials-An in vitro and in vivo study.

    Science.gov (United States)

    Weizbauer, Andreas; Kieke, Marc; Rahim, Muhammad Imran; Angrisani, Gian Luigi; Willbold, Elmar; Diekmann, Julia; Flrkemeier, Thilo; Windhagen, Henning; Mller, Peter Paul; Behrens, Peter; Budde, Stefan

    2016-04-01

    The total hip arthroplasty is one of the most common artificial joint replacement procedures. Several different surface coatings have been shown to improve implant fixation by facilitating bone ingrowth and consequently enhancing the longevity of uncemented orthopaedic hip prostheses. In the present study, two different layered double hydroxides (LDHs), Mg-Fe- and Mg-Al-LDH, were investigated as potential magnesium (Mg)-containing coating materials for orthopaedic applications in comparison to Mg hydroxide (Mg(OH)2 ). In vitro direct cell compatibility tests were carried out using the murine fibroblast cell line NIH 3T3 and the mouse osteosarcoma cell line MG 63. The host response of bone tissue was evaluated in in vivo experiments with nine rabbits. Two cylindrical pellets (3 3 mm) were implanted into each femoral condyle of the left hind leg. The samples were analyzed histologically and with ?-computed tomography (?-CT) 6 weeks after surgery. An in vitro cytotoxicity test determined that more cells grew on the LDH pellets than on the Mg(OH)2 -pellets. The pH value and the Mg(2+) content of the cell culture media were increased after incubation of the cells on the degradable samples. The in vivo tests demonstrated the formation of fibrous capsules around Mg(OH)2 and Mg-Fe-LDH. In contrast, the host response of the Mg-Al-LDH samples indicated that this Mg-containing biomaterial is a potential candidate for implant coating. 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 525-531, 2016. PMID:25939995

  12. Fast and robust infiltration of functional material inside titania nanotube layers: case study of a chalcogenide glass sensitizer

    OpenAIRE

    Macák, M. Jan; Kohoutek, Tomáš; Wang, Lidong; Beránek, Radim

    2013-01-01

    Fast and robust infiltration of anodic TiO2 nanotube layers with a model chalcogenide As3S7 glass via spin-coating is reported for the first time. Effective sensitization leads to a significant visible light photocurrent response. This easy and cheap infiltration method can be extended for deposition of other absorbers into nanotubular layers.

  13. The effect of doping (Mn,B)3O4 materials as protective layers in different metallic interconnects for Solid Oxide Fuel Cells

    Science.gov (United States)

    Miguel-Prez, Vernica; Martnez-Amesti, Ana; N, Mara Luisa; Larraaga, Aitor; Arriortua, Mara Isabel

    2013-12-01

    Spinel oxides with the general formula of (Mn,B)3O4 (B = Co, Fe) were used as barrier materials between the cathode and the metallic interconnect to reduce the rate of cathode degradation by Cr poisoning. The effect of doping at the B position was investigated terms of microstructure and electrical conductivity to determine its behaviour and effectiveness as a protective layer in contact with three metallic materials (Crofer 22 APU, SS430 and Conicro 4023 W 188). The analysis showed that the use of these materials considerably decreased the reactivity and diffusion of Cr between the cathode and the metallic interconnects. The protective layer doped with Fe at the B position exhibited the least amount of reactivity with the interconnector and cathode materials. The worst results were observed for SS430 cells coated with a protective layer perhaps due to their low Cr content. The Crofer 22 APU and Conicro 4023 W 188 samples exhibited very similar conductivity results in the presence of the MnCo1.9Fe0.1O4 protective coating. As a result, these two material combinations are a promising option for use as bipolar plates in SOFC.

  14. Simultaneous control of thermoelectric properties in p-type and n-type materials by electric double-layer gating : New design for thermoelectric device

    OpenAIRE

    Takayanagi, Ryohei; Fujii, Takenori; Asamitsu, Atsushi

    2015-01-01

    We report novel design for thermoelectric device which can control thermoelectric properties of p-type and n-type materials simultaneously by electric double-layer gating. Here, p-type Cu2O and n-type ZnO were used as positive and negative electrodes of the electric double-layer capacitor structure. When the gate voltage was applied between two electrodes, the holes and electrons were accumulated on the surface of Cu2O and ZnO, respectively. The thermopower was measured by applying thermal gr...

  15. Microstructure of interdiffused layer formed by electron beam self-material brazing of Nb-1Zr alloy and 1Cr18Ni9 stainless steel

    International Nuclear Information System (INIS)

    The microstructure and the element profiles of the interdiffused layer formed by electron beam self-material brazing of Nb-1Zr alloy to 1Cr18Ni9 stainless steel was examined by SEM, TEM and EDS. It is found that constituent element interdiffusion is strongly occurred through interface between two materials and an interdiffused layer is formed during electron beam self-materials brazing. The transmission electron morphologies of interdiffused layer shows two sets of microstructures in it, one is a strip precipitated phase and the other is a matrix phase based on bulk material. Moreover, the strip precipitation is a full laminated structure which contains two kinds of full laminated precipitated phases. From indexing of the SADP patterns of precipitated phases, it may conclude that the two full laminated precipitated phases are SADP patterns of precipitated phases, it may conclude that the two full laminated precipitated phases are ?-Fe(Ni)7Nb6 and ?-FeCr, respectively, the matrix phase is belong to ?-Fe(Cr, Ni, Nb, C) phase. (author)

  16. Study of deuterium retention in/release from ITER-relevant Be-containing mixed material layers implanted at elevated temperatures

    International Nuclear Information System (INIS)

    D implantation into Be-containing mixed material layers: Be, BeW (W: ?6 at.%) and BeC (C: ?50 at.%), was performed at elevated temperatures. The temperature dependence of D retention varied depending on the admixed element. D retention in Be and BeW layers decreases with increasing implantation temperature, while the BeC layers maintained rather high D retention in the present investigated temperature range (up to 623 K). D desorption behaviour from BeC suggests the contribution of CD bonds to D retention. W admixture into Be can significantly suppress D retention in Be. Long-term isothermal annealing at 513 and 623 K for D removal was also performed to simulate the ITER-wall-baking scenario. Even extended annealing at temperatures comparable to or lower than the implantation temperature does not lead to a significant release of retained D

  17. Flaw detection in multi-layer, multi-material composites by resonance imaging: Utilizing Air-coupled Ultrasonics and Finite Element Modeling

    Science.gov (United States)

    Livings, Richard Andrew

    2011-12-01

    Ceramic tiles are the main ingredient of a multi-material, multi-layered composite being considered for the modernization of tank armors. The high stiffness, low attenuation, and precise dimensions of these uniform tiles make them remarkable resonators when driven to vibrate. Defects in the tile, during manufacture or after usage, are expected to change the resonance frequencies and resonance images of the tile. The comparison of the resonance frequencies and resonance images of a pristine tile/lay-up to a defective tile/lay-up will thus be a quantitative damage metric. By examining the vibrational behavior of these tiles and the composite lay-up with Finite Element Modeling and analytical plate vibration equations, the development of a new Nondestructive Evaluation technique is possible. This study examines the development of the Air-Coupled Ultrasonic Resonance Imaging technique as applied to a hexagonal ceramic tile and a multi-material, multi-layered composite.

  18. The performance of a two-layer biotrickling filter filled with new mixed packing materials for the removal of H2S from air.

    Science.gov (United States)

    Chen, Yingwen; Wang, Xiaojun; He, Shuo; Zhu, Shemin; Shen, Shubao

    2016-01-01

    In the work described here, a two-layer biotrickling filter filled with new packing materials was used to remove H2S from air. The upper layer of the filter was packed with activated carbon-loaded polyurethane, whereas the lower layer was filled with modified organism-suspended fillers. The effects of inlet load, empty bed residence time (EBRT) from 79s to 53s, pH and contaminant starvation time were investigated. For loads of 15-50g/(m(3)h), the average removal efficiency (RE) was higher than 96% under a consistent supply of pollutants. The critical elimination capacity was 39.95g/(m(3)h) for an EBRT of 53s with an RE of 99.9%. The two-layer BTF was capable of withstanding contaminant starvation periods for 1.5d and 7d with only a few hours of recovery time. The biodegradation kinetics was studied using Michaelis-Menten type equations under different EBRTs. At an EBRT of 66s, the optimal kinetic constants rmax and Km were 333.3g/(m(3)h) and 0.93g/m(3), respectively. During the operation, the two-layer BTF performed well under various reasonable conditions. PMID:26397031

  19. Material properties of interfacial silicate layer and its influence on the electrical characteristics of MOS devices using hafnia as the gate dielectric

    International Nuclear Information System (INIS)

    This work deals with some fundamental material properties of the hafnia or hafnium oxide and the silicate layer at the Si/HfO2 interface. It is realized that one of the fundamental features of the HfO2 film is that its lowest conduction band states are composed mainly by d states instead of s and p states as is in the case for SiO2. There is only a very small covalent component contributed from Hf d and O 2p states and the Hf-O bond is predominantly ionic. This is the reason for the small band gap and small conduction band offset energy. This feature also gives rise to thermal instabilities and the formation of an interfacial silicate layer. Although the formation of the silicate structure will help to build a more stable interface, long metallic silicide bonds will result as a by-product when the metal oxide reacts with the Si substrate to form this silicate layer. The existence of metallic silicide bonds is one of the major reasons for the observed high-interface trap density of the HfO2/Si structure. Because of the large difference in dielectric constant between the bulk hafnia and interfacial silicate, the electric field will be distributed mainly across the low-? interface layer, which in effect reduces the interface barrier height for electron tunneling injection and the effective breakdown voltage of the low-? layer

  20. Spherical natural graphite coated by a thick layer of carbonaceous mesophase for use as an anode material in lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Wan, C.Y.; Li, H.; Wu, M.C.; Zhao, C.J. [Shanghai Institute of Technology, Shanghai (China)

    2009-07-15

    A method for coating a thick layer of carbonaceous mesophase was developed to treat spherical natural graphite (SNG) for use as anodes in lithium ion batteries. The carbonaceous mesophase layer was fabricated by heat treatment of a mixture of SNG and coal tar pitch. The thickness of the carbonaceous mesophase on the surface of the SNG was approximately 2.5 {mu} m, which is effective for enhancing the strength of the carbonaceous mesophase shell and for allowing the shell to maintain good integrity at a high anode density (1.6 g cm{sup -3}). The mesophase layer increased the initial columbic efficiency from approximately 90% to 95%, dramatically improved the capacity retention and reduced the irreversible capacity by greatly decreasing the SNG surface area. The initial efficiency, cycle life and rate capability for the SNG anode covered by a thick mesophase layer gave comparable results as the mesocarbon microbeads (MCMB) anode, while the SNG anode reversible capacity of 341 mAh g{sup -1} was higher than that of MCMB, 319 mAh g{sup -1}. Electrochemical measurements showed that SNG particles coated by a thick carbonaceous mesophase layer are strong candidates for use as possible anode materials in high energy density lithium ion batteries.